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From: Zhihao Cheng <chengzhihao1@huawei.com>
To: <richard@nod.at>, <david.oberhollenzer@sigma-star.at>,
	<miquel.raynal@bootlin.com>, <yi.zhang@huawei.com>, <xiangyang3@huawei.com>,
	<huangxiaojia2@huawei.com>
CC: <linux-mtd@lists.infradead.org>, <linux-kernel@vger.kernel.org>
Subject: [RFC PATCH mtd-utils 016/110] ubifs-utils: Import UBIFS libs from linux kernel
Date: Fri, 7 Jun 2024 12:24:41 +0800
Message-ID: <20240607042615.2069840-17-chengzhihao1@huawei.com>
In-Reply-To: <20240607042615.2069840-1-chengzhihao1@huawei.com>
References: <20240607042615.2069840-1-chengzhihao1@huawei.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8bit

Import UBIFS libs from linux kernel. Next patches will replace ubifs
related source code with implementation of linux kernel, which makes
userspace implementation be same with linux kernel, then fsck.ubifs
can resuse the code.

Notice: lpt.c is modified with [1] applied. ubifs.h and orphan.c are
modified with [2] applied, journal.c is modified with [3] reverted(
because fsck runs in a single thread, so waitqueue is not needed to
be implemented in userspace.).
[1] https://lore.kernel.org/linux-mtd/20231228014112.2836317-13-chengzhihao1@huawei.com/
[2] https://lore.kernel.org/linux-mtd/20240410073751.2522830-1-chengzhihao1@huawei.com/
[3] https://lore.kernel.org/linux-mtd/20240122063103.359501-1-chengzhihao1@huawei.com/

Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com>
---
 ubifs-utils/libubifs/auth.c       |  545 ++++++
 ubifs-utils/libubifs/budget.c     |  714 ++++++++
 ubifs-utils/libubifs/commit.c     |  733 ++++++++
 ubifs-utils/libubifs/debug.c      | 3051 +++++++++++++++++++++++++++++++
 ubifs-utils/libubifs/debug.h      |  304 ++++
 ubifs-utils/libubifs/dir.c        | 1744 ++++++++++++++++++
 ubifs-utils/libubifs/find.c       |  963 ++++++++++
 ubifs-utils/libubifs/gc.c         | 1017 +++++++++++
 ubifs-utils/libubifs/io.c         | 1268 +++++++++++++
 ubifs-utils/libubifs/journal.c    | 1928 ++++++++++++++++++++
 ubifs-utils/libubifs/key.h        |  543 ++++++
 ubifs-utils/libubifs/log.c        |  762 ++++++++
 ubifs-utils/libubifs/lprops.c     | 1307 ++++++++++++++
 ubifs-utils/libubifs/lpt.c        | 2451 +++++++++++++++++++++++++
 ubifs-utils/libubifs/lpt_commit.c | 1997 +++++++++++++++++++++
 ubifs-utils/libubifs/master.c     |  473 +++++
 ubifs-utils/libubifs/misc.h       |  289 +++
 ubifs-utils/libubifs/orphan.c     |  947 ++++++++++
 ubifs-utils/libubifs/recovery.c   | 1588 +++++++++++++++++
 ubifs-utils/libubifs/replay.c     | 1250 +++++++++++++
 ubifs-utils/libubifs/sb.c         |  956 ++++++++++
 ubifs-utils/libubifs/scan.c       |  366 ++++
 ubifs-utils/libubifs/super.c      | 2505 ++++++++++++++++++++++++++
 ubifs-utils/libubifs/tnc.c        | 3553 +++++++++++++++++++++++++++++++++++++
 ubifs-utils/libubifs/tnc_commit.c | 1111 ++++++++++++
 ubifs-utils/libubifs/tnc_misc.c   |  524 ++++++
 ubifs-utils/libubifs/ubifs.h      | 2164 ++++++++++++++++++++++
 27 files changed, 35053 insertions(+)
 create mode 100644 ubifs-utils/libubifs/auth.c
 create mode 100644 ubifs-utils/libubifs/budget.c
 create mode 100644 ubifs-utils/libubifs/commit.c
 create mode 100644 ubifs-utils/libubifs/debug.c
 create mode 100644 ubifs-utils/libubifs/debug.h
 create mode 100644 ubifs-utils/libubifs/dir.c
 create mode 100644 ubifs-utils/libubifs/find.c
 create mode 100644 ubifs-utils/libubifs/gc.c
 create mode 100644 ubifs-utils/libubifs/io.c
 create mode 100644 ubifs-utils/libubifs/journal.c
 create mode 100644 ubifs-utils/libubifs/key.h
 create mode 100644 ubifs-utils/libubifs/log.c
 create mode 100644 ubifs-utils/libubifs/lprops.c
 create mode 100644 ubifs-utils/libubifs/lpt.c
 create mode 100644 ubifs-utils/libubifs/lpt_commit.c
 create mode 100644 ubifs-utils/libubifs/master.c
 create mode 100644 ubifs-utils/libubifs/misc.h
 create mode 100644 ubifs-utils/libubifs/orphan.c
 create mode 100644 ubifs-utils/libubifs/recovery.c
 create mode 100644 ubifs-utils/libubifs/replay.c
 create mode 100644 ubifs-utils/libubifs/sb.c
 create mode 100644 ubifs-utils/libubifs/scan.c
 create mode 100644 ubifs-utils/libubifs/super.c
 create mode 100644 ubifs-utils/libubifs/tnc.c
 create mode 100644 ubifs-utils/libubifs/tnc_commit.c
 create mode 100644 ubifs-utils/libubifs/tnc_misc.c
 create mode 100644 ubifs-utils/libubifs/ubifs.h

diff --git a/ubifs-utils/libubifs/auth.c b/ubifs-utils/libubifs/auth.c
new file mode 100644
index 00000000..0d561ecb
--- /dev/null
+++ b/ubifs-utils/libubifs/auth.c
@@ -0,0 +1,545 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2018 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
+ */
+
+/*
+ * This file implements various helper functions for UBIFS authentication support
+ */
+
+#include <linux/verification.h>
+#include <crypto/hash.h>
+#include <crypto/utils.h>
+#include <keys/user-type.h>
+#include <keys/asymmetric-type.h>
+
+#include "ubifs.h"
+
+/**
+ * ubifs_node_calc_hash - calculate the hash of a UBIFS node
+ * @c: UBIFS file-system description object
+ * @node: the node to calculate a hash for
+ * @hash: the returned hash
+ *
+ * Returns 0 for success or a negative error code otherwise.
+ */
+int __ubifs_node_calc_hash(const struct ubifs_info *c, const void *node,
+			    u8 *hash)
+{
+	const struct ubifs_ch *ch = node;
+
+	return crypto_shash_tfm_digest(c->hash_tfm, node, le32_to_cpu(ch->len),
+				       hash);
+}
+
+/**
+ * ubifs_hash_calc_hmac - calculate a HMAC from a hash
+ * @c: UBIFS file-system description object
+ * @hash: the node to calculate a HMAC for
+ * @hmac: the returned HMAC
+ *
+ * Returns 0 for success or a negative error code otherwise.
+ */
+static int ubifs_hash_calc_hmac(const struct ubifs_info *c, const u8 *hash,
+				 u8 *hmac)
+{
+	return crypto_shash_tfm_digest(c->hmac_tfm, hash, c->hash_len, hmac);
+}
+
+/**
+ * ubifs_prepare_auth_node - Prepare an authentication node
+ * @c: UBIFS file-system description object
+ * @node: the node to calculate a hash for
+ * @inhash: input hash of previous nodes
+ *
+ * This function prepares an authentication node for writing onto flash.
+ * It creates a HMAC from the given input hash and writes it to the node.
+ *
+ * Returns 0 for success or a negative error code otherwise.
+ */
+int ubifs_prepare_auth_node(struct ubifs_info *c, void *node,
+			     struct shash_desc *inhash)
+{
+	struct ubifs_auth_node *auth = node;
+	u8 hash[UBIFS_HASH_ARR_SZ];
+	int err;
+
+	{
+		SHASH_DESC_ON_STACK(hash_desc, c->hash_tfm);
+
+		hash_desc->tfm = c->hash_tfm;
+		ubifs_shash_copy_state(c, inhash, hash_desc);
+
+		err = crypto_shash_final(hash_desc, hash);
+		if (err)
+			return err;
+	}
+
+	err = ubifs_hash_calc_hmac(c, hash, auth->hmac);
+	if (err)
+		return err;
+
+	auth->ch.node_type = UBIFS_AUTH_NODE;
+	ubifs_prepare_node(c, auth, ubifs_auth_node_sz(c), 0);
+	return 0;
+}
+
+static struct shash_desc *ubifs_get_desc(const struct ubifs_info *c,
+					 struct crypto_shash *tfm)
+{
+	struct shash_desc *desc;
+	int err;
+
+	if (!ubifs_authenticated(c))
+		return NULL;
+
+	desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(tfm), GFP_KERNEL);
+	if (!desc)
+		return ERR_PTR(-ENOMEM);
+
+	desc->tfm = tfm;
+
+	err = crypto_shash_init(desc);
+	if (err) {
+		kfree(desc);
+		return ERR_PTR(err);
+	}
+
+	return desc;
+}
+
+/**
+ * __ubifs_hash_get_desc - get a descriptor suitable for hashing a node
+ * @c: UBIFS file-system description object
+ *
+ * This function returns a descriptor suitable for hashing a node. Free after use
+ * with kfree.
+ */
+struct shash_desc *__ubifs_hash_get_desc(const struct ubifs_info *c)
+{
+	return ubifs_get_desc(c, c->hash_tfm);
+}
+
+/**
+ * ubifs_bad_hash - Report hash mismatches
+ * @c: UBIFS file-system description object
+ * @node: the node
+ * @hash: the expected hash
+ * @lnum: the LEB @node was read from
+ * @offs: offset in LEB @node was read from
+ *
+ * This function reports a hash mismatch when a node has a different hash than
+ * expected.
+ */
+void ubifs_bad_hash(const struct ubifs_info *c, const void *node, const u8 *hash,
+		    int lnum, int offs)
+{
+	int len = min(c->hash_len, 20);
+	int cropped = len != c->hash_len;
+	const char *cont = cropped ? "..." : "";
+
+	u8 calc[UBIFS_HASH_ARR_SZ];
+
+	__ubifs_node_calc_hash(c, node, calc);
+
+	ubifs_err(c, "hash mismatch on node at LEB %d:%d", lnum, offs);
+	ubifs_err(c, "hash expected:   %*ph%s", len, hash, cont);
+	ubifs_err(c, "hash calculated: %*ph%s", len, calc, cont);
+}
+
+/**
+ * __ubifs_node_check_hash - check the hash of a node against given hash
+ * @c: UBIFS file-system description object
+ * @node: the node
+ * @expected: the expected hash
+ *
+ * This function calculates a hash over a node and compares it to the given hash.
+ * Returns 0 if both hashes are equal or authentication is disabled, otherwise a
+ * negative error code is returned.
+ */
+int __ubifs_node_check_hash(const struct ubifs_info *c, const void *node,
+			    const u8 *expected)
+{
+	u8 calc[UBIFS_HASH_ARR_SZ];
+	int err;
+
+	err = __ubifs_node_calc_hash(c, node, calc);
+	if (err)
+		return err;
+
+	if (ubifs_check_hash(c, expected, calc))
+		return -EPERM;
+
+	return 0;
+}
+
+/**
+ * ubifs_sb_verify_signature - verify the signature of a superblock
+ * @c: UBIFS file-system description object
+ * @sup: The superblock node
+ *
+ * To support offline signed images the superblock can be signed with a
+ * PKCS#7 signature. The signature is placed directly behind the superblock
+ * node in an ubifs_sig_node.
+ *
+ * Returns 0 when the signature can be successfully verified or a negative
+ * error code if not.
+ */
+int ubifs_sb_verify_signature(struct ubifs_info *c,
+			      const struct ubifs_sb_node *sup)
+{
+	int err;
+	struct ubifs_scan_leb *sleb;
+	struct ubifs_scan_node *snod;
+	const struct ubifs_sig_node *signode;
+
+	sleb = ubifs_scan(c, UBIFS_SB_LNUM, UBIFS_SB_NODE_SZ, c->sbuf, 0);
+	if (IS_ERR(sleb)) {
+		err = PTR_ERR(sleb);
+		return err;
+	}
+
+	if (sleb->nodes_cnt == 0) {
+		ubifs_err(c, "Unable to find signature node");
+		err = -EINVAL;
+		goto out_destroy;
+	}
+
+	snod = list_first_entry(&sleb->nodes, struct ubifs_scan_node, list);
+
+	if (snod->type != UBIFS_SIG_NODE) {
+		ubifs_err(c, "Signature node is of wrong type");
+		err = -EINVAL;
+		goto out_destroy;
+	}
+
+	signode = snod->node;
+
+	if (le32_to_cpu(signode->len) > snod->len + sizeof(struct ubifs_sig_node)) {
+		ubifs_err(c, "invalid signature len %d", le32_to_cpu(signode->len));
+		err = -EINVAL;
+		goto out_destroy;
+	}
+
+	if (le32_to_cpu(signode->type) != UBIFS_SIGNATURE_TYPE_PKCS7) {
+		ubifs_err(c, "Signature type %d is not supported\n",
+			  le32_to_cpu(signode->type));
+		err = -EINVAL;
+		goto out_destroy;
+	}
+
+	err = verify_pkcs7_signature(sup, sizeof(struct ubifs_sb_node),
+				     signode->sig, le32_to_cpu(signode->len),
+				     NULL, VERIFYING_UNSPECIFIED_SIGNATURE,
+				     NULL, NULL);
+
+	if (err)
+		ubifs_err(c, "Failed to verify signature");
+	else
+		ubifs_msg(c, "Successfully verified super block signature");
+
+out_destroy:
+	ubifs_scan_destroy(sleb);
+
+	return err;
+}
+
+/**
+ * ubifs_init_authentication - initialize UBIFS authentication support
+ * @c: UBIFS file-system description object
+ *
+ * This function returns 0 for success or a negative error code otherwise.
+ */
+int ubifs_init_authentication(struct ubifs_info *c)
+{
+	struct key *keyring_key;
+	const struct user_key_payload *ukp;
+	int err;
+	char hmac_name[CRYPTO_MAX_ALG_NAME];
+
+	if (!c->auth_hash_name) {
+		ubifs_err(c, "authentication hash name needed with authentication");
+		return -EINVAL;
+	}
+
+	c->auth_hash_algo = match_string(hash_algo_name, HASH_ALGO__LAST,
+					 c->auth_hash_name);
+	if ((int)c->auth_hash_algo < 0) {
+		ubifs_err(c, "Unknown hash algo %s specified",
+			  c->auth_hash_name);
+		return -EINVAL;
+	}
+
+	snprintf(hmac_name, CRYPTO_MAX_ALG_NAME, "hmac(%s)",
+		 c->auth_hash_name);
+
+	keyring_key = request_key(&key_type_logon, c->auth_key_name, NULL);
+
+	if (IS_ERR(keyring_key)) {
+		ubifs_err(c, "Failed to request key: %ld",
+			  PTR_ERR(keyring_key));
+		return PTR_ERR(keyring_key);
+	}
+
+	down_read(&keyring_key->sem);
+
+	if (keyring_key->type != &key_type_logon) {
+		ubifs_err(c, "key type must be logon");
+		err = -ENOKEY;
+		goto out;
+	}
+
+	ukp = user_key_payload_locked(keyring_key);
+	if (!ukp) {
+		/* key was revoked before we acquired its semaphore */
+		err = -EKEYREVOKED;
+		goto out;
+	}
+
+	c->hash_tfm = crypto_alloc_shash(c->auth_hash_name, 0, 0);
+	if (IS_ERR(c->hash_tfm)) {
+		err = PTR_ERR(c->hash_tfm);
+		ubifs_err(c, "Can not allocate %s: %d",
+			  c->auth_hash_name, err);
+		goto out;
+	}
+
+	c->hash_len = crypto_shash_digestsize(c->hash_tfm);
+	if (c->hash_len > UBIFS_HASH_ARR_SZ) {
+		ubifs_err(c, "hash %s is bigger than maximum allowed hash size (%d > %d)",
+			  c->auth_hash_name, c->hash_len, UBIFS_HASH_ARR_SZ);
+		err = -EINVAL;
+		goto out_free_hash;
+	}
+
+	c->hmac_tfm = crypto_alloc_shash(hmac_name, 0, 0);
+	if (IS_ERR(c->hmac_tfm)) {
+		err = PTR_ERR(c->hmac_tfm);
+		ubifs_err(c, "Can not allocate %s: %d", hmac_name, err);
+		goto out_free_hash;
+	}
+
+	c->hmac_desc_len = crypto_shash_digestsize(c->hmac_tfm);
+	if (c->hmac_desc_len > UBIFS_HMAC_ARR_SZ) {
+		ubifs_err(c, "hmac %s is bigger than maximum allowed hmac size (%d > %d)",
+			  hmac_name, c->hmac_desc_len, UBIFS_HMAC_ARR_SZ);
+		err = -EINVAL;
+		goto out_free_hmac;
+	}
+
+	err = crypto_shash_setkey(c->hmac_tfm, ukp->data, ukp->datalen);
+	if (err)
+		goto out_free_hmac;
+
+	c->authenticated = true;
+
+	c->log_hash = ubifs_hash_get_desc(c);
+	if (IS_ERR(c->log_hash)) {
+		err = PTR_ERR(c->log_hash);
+		goto out_free_hmac;
+	}
+
+	err = 0;
+
+out_free_hmac:
+	if (err)
+		crypto_free_shash(c->hmac_tfm);
+out_free_hash:
+	if (err)
+		crypto_free_shash(c->hash_tfm);
+out:
+	up_read(&keyring_key->sem);
+	key_put(keyring_key);
+
+	return err;
+}
+
+/**
+ * __ubifs_exit_authentication - release resource
+ * @c: UBIFS file-system description object
+ *
+ * This function releases the authentication related resources.
+ */
+void __ubifs_exit_authentication(struct ubifs_info *c)
+{
+	if (!ubifs_authenticated(c))
+		return;
+
+	crypto_free_shash(c->hmac_tfm);
+	crypto_free_shash(c->hash_tfm);
+	kfree(c->log_hash);
+}
+
+/**
+ * ubifs_node_calc_hmac - calculate the HMAC of a UBIFS node
+ * @c: UBIFS file-system description object
+ * @node: the node to insert a HMAC into.
+ * @len: the length of the node
+ * @ofs_hmac: the offset in the node where the HMAC is inserted
+ * @hmac: returned HMAC
+ *
+ * This function calculates a HMAC of a UBIFS node. The HMAC is expected to be
+ * embedded into the node, so this area is not covered by the HMAC. Also not
+ * covered is the UBIFS_NODE_MAGIC and the CRC of the node.
+ */
+static int ubifs_node_calc_hmac(const struct ubifs_info *c, const void *node,
+				int len, int ofs_hmac, void *hmac)
+{
+	SHASH_DESC_ON_STACK(shash, c->hmac_tfm);
+	int hmac_len = c->hmac_desc_len;
+	int err;
+
+	ubifs_assert(c, ofs_hmac > 8);
+	ubifs_assert(c, ofs_hmac + hmac_len < len);
+
+	shash->tfm = c->hmac_tfm;
+
+	err = crypto_shash_init(shash);
+	if (err)
+		return err;
+
+	/* behind common node header CRC up to HMAC begin */
+	err = crypto_shash_update(shash, node + 8, ofs_hmac - 8);
+	if (err < 0)
+		return err;
+
+	/* behind HMAC, if any */
+	if (len - ofs_hmac - hmac_len > 0) {
+		err = crypto_shash_update(shash, node + ofs_hmac + hmac_len,
+			    len - ofs_hmac - hmac_len);
+		if (err < 0)
+			return err;
+	}
+
+	return crypto_shash_final(shash, hmac);
+}
+
+/**
+ * __ubifs_node_insert_hmac - insert a HMAC into a UBIFS node
+ * @c: UBIFS file-system description object
+ * @node: the node to insert a HMAC into.
+ * @len: the length of the node
+ * @ofs_hmac: the offset in the node where the HMAC is inserted
+ *
+ * This function inserts a HMAC at offset @ofs_hmac into the node given in
+ * @node.
+ *
+ * This function returns 0 for success or a negative error code otherwise.
+ */
+int __ubifs_node_insert_hmac(const struct ubifs_info *c, void *node, int len,
+			    int ofs_hmac)
+{
+	return ubifs_node_calc_hmac(c, node, len, ofs_hmac, node + ofs_hmac);
+}
+
+/**
+ * __ubifs_node_verify_hmac - verify the HMAC of UBIFS node
+ * @c: UBIFS file-system description object
+ * @node: the node to insert a HMAC into.
+ * @len: the length of the node
+ * @ofs_hmac: the offset in the node where the HMAC is inserted
+ *
+ * This function verifies the HMAC at offset @ofs_hmac of the node given in
+ * @node. Returns 0 if successful or a negative error code otherwise.
+ */
+int __ubifs_node_verify_hmac(const struct ubifs_info *c, const void *node,
+			     int len, int ofs_hmac)
+{
+	int hmac_len = c->hmac_desc_len;
+	u8 *hmac;
+	int err;
+
+	hmac = kmalloc(hmac_len, GFP_NOFS);
+	if (!hmac)
+		return -ENOMEM;
+
+	err = ubifs_node_calc_hmac(c, node, len, ofs_hmac, hmac);
+	if (err) {
+		kfree(hmac);
+		return err;
+	}
+
+	err = crypto_memneq(hmac, node + ofs_hmac, hmac_len);
+
+	kfree(hmac);
+
+	if (!err)
+		return 0;
+
+	return -EPERM;
+}
+
+int __ubifs_shash_copy_state(const struct ubifs_info *c, struct shash_desc *src,
+			     struct shash_desc *target)
+{
+	u8 *state;
+	int err;
+
+	state = kmalloc(crypto_shash_descsize(src->tfm), GFP_NOFS);
+	if (!state)
+		return -ENOMEM;
+
+	err = crypto_shash_export(src, state);
+	if (err)
+		goto out;
+
+	err = crypto_shash_import(target, state);
+
+out:
+	kfree(state);
+
+	return err;
+}
+
+/**
+ * ubifs_hmac_wkm - Create a HMAC of the well known message
+ * @c: UBIFS file-system description object
+ * @hmac: The HMAC of the well known message
+ *
+ * This function creates a HMAC of a well known message. This is used
+ * to check if the provided key is suitable to authenticate a UBIFS
+ * image. This is only a convenience to the user to provide a better
+ * error message when the wrong key is provided.
+ *
+ * This function returns 0 for success or a negative error code otherwise.
+ */
+int ubifs_hmac_wkm(struct ubifs_info *c, u8 *hmac)
+{
+	SHASH_DESC_ON_STACK(shash, c->hmac_tfm);
+	int err;
+	const char well_known_message[] = "UBIFS";
+
+	if (!ubifs_authenticated(c))
+		return 0;
+
+	shash->tfm = c->hmac_tfm;
+
+	err = crypto_shash_init(shash);
+	if (err)
+		return err;
+
+	err = crypto_shash_update(shash, well_known_message,
+				  sizeof(well_known_message) - 1);
+	if (err < 0)
+		return err;
+
+	err = crypto_shash_final(shash, hmac);
+	if (err)
+		return err;
+	return 0;
+}
+
+/*
+ * ubifs_hmac_zero - test if a HMAC is zero
+ * @c: UBIFS file-system description object
+ * @hmac: the HMAC to test
+ *
+ * This function tests if a HMAC is zero and returns true if it is
+ * and false otherwise.
+ */
+bool ubifs_hmac_zero(struct ubifs_info *c, const u8 *hmac)
+{
+	return !memchr_inv(hmac, 0, c->hmac_desc_len);
+}
diff --git a/ubifs-utils/libubifs/budget.c b/ubifs-utils/libubifs/budget.c
new file mode 100644
index 00000000..d76eb7b3
--- /dev/null
+++ b/ubifs-utils/libubifs/budget.c
@@ -0,0 +1,714 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file implements the budgeting sub-system which is responsible for UBIFS
+ * space management.
+ *
+ * Factors such as compression, wasted space at the ends of LEBs, space in other
+ * journal heads, the effect of updates on the index, and so on, make it
+ * impossible to accurately predict the amount of space needed. Consequently
+ * approximations are used.
+ */
+
+#include "ubifs.h"
+#include <linux/writeback.h>
+#include <linux/math64.h>
+
+/*
+ * When pessimistic budget calculations say that there is no enough space,
+ * UBIFS starts writing back dirty inodes and pages, doing garbage collection,
+ * or committing. The below constant defines maximum number of times UBIFS
+ * repeats the operations.
+ */
+#define MAX_MKSPC_RETRIES 3
+
+/*
+ * The below constant defines amount of dirty pages which should be written
+ * back at when trying to shrink the liability.
+ */
+#define NR_TO_WRITE 16
+
+/**
+ * shrink_liability - write-back some dirty pages/inodes.
+ * @c: UBIFS file-system description object
+ * @nr_to_write: how many dirty pages to write-back
+ *
+ * This function shrinks UBIFS liability by means of writing back some amount
+ * of dirty inodes and their pages.
+ *
+ * Note, this function synchronizes even VFS inodes which are locked
+ * (@i_mutex) by the caller of the budgeting function, because write-back does
+ * not touch @i_mutex.
+ */
+static void shrink_liability(struct ubifs_info *c, int nr_to_write)
+{
+	down_read(&c->vfs_sb->s_umount);
+	writeback_inodes_sb_nr(c->vfs_sb, nr_to_write, WB_REASON_FS_FREE_SPACE);
+	up_read(&c->vfs_sb->s_umount);
+}
+
+/**
+ * run_gc - run garbage collector.
+ * @c: UBIFS file-system description object
+ *
+ * This function runs garbage collector to make some more free space. Returns
+ * zero if a free LEB has been produced, %-EAGAIN if commit is required, and a
+ * negative error code in case of failure.
+ */
+static int run_gc(struct ubifs_info *c)
+{
+	int lnum;
+
+	/* Make some free space by garbage-collecting dirty space */
+	down_read(&c->commit_sem);
+	lnum = ubifs_garbage_collect(c, 1);
+	up_read(&c->commit_sem);
+	if (lnum < 0)
+		return lnum;
+
+	/* GC freed one LEB, return it to lprops */
+	dbg_budg("GC freed LEB %d", lnum);
+	return ubifs_return_leb(c, lnum);
+}
+
+/**
+ * get_liability - calculate current liability.
+ * @c: UBIFS file-system description object
+ *
+ * This function calculates and returns current UBIFS liability, i.e. the
+ * amount of bytes UBIFS has "promised" to write to the media.
+ */
+static long long get_liability(struct ubifs_info *c)
+{
+	long long liab;
+
+	spin_lock(&c->space_lock);
+	liab = c->bi.idx_growth + c->bi.data_growth + c->bi.dd_growth;
+	spin_unlock(&c->space_lock);
+	return liab;
+}
+
+/**
+ * make_free_space - make more free space on the file-system.
+ * @c: UBIFS file-system description object
+ *
+ * This function is called when an operation cannot be budgeted because there
+ * is supposedly no free space. But in most cases there is some free space:
+ *   o budgeting is pessimistic, so it always budgets more than it is actually
+ *     needed, so shrinking the liability is one way to make free space - the
+ *     cached data will take less space then it was budgeted for;
+ *   o GC may turn some dark space into free space (budgeting treats dark space
+ *     as not available);
+ *   o commit may free some LEB, i.e., turn freeable LEBs into free LEBs.
+ *
+ * So this function tries to do the above. Returns %-EAGAIN if some free space
+ * was presumably made and the caller has to re-try budgeting the operation.
+ * Returns %-ENOSPC if it couldn't do more free space, and other negative error
+ * codes on failures.
+ */
+static int make_free_space(struct ubifs_info *c)
+{
+	int err, retries = 0;
+	long long liab1, liab2;
+
+	do {
+		liab1 = get_liability(c);
+		/*
+		 * We probably have some dirty pages or inodes (liability), try
+		 * to write them back.
+		 */
+		dbg_budg("liability %lld, run write-back", liab1);
+		shrink_liability(c, NR_TO_WRITE);
+
+		liab2 = get_liability(c);
+		if (liab2 < liab1)
+			return -EAGAIN;
+
+		dbg_budg("new liability %lld (not shrunk)", liab2);
+
+		/* Liability did not shrink again, try GC */
+		dbg_budg("Run GC");
+		err = run_gc(c);
+		if (!err)
+			return -EAGAIN;
+
+		if (err != -EAGAIN && err != -ENOSPC)
+			/* Some real error happened */
+			return err;
+
+		dbg_budg("Run commit (retries %d)", retries);
+		err = ubifs_run_commit(c);
+		if (err)
+			return err;
+	} while (retries++ < MAX_MKSPC_RETRIES);
+
+	return -ENOSPC;
+}
+
+/**
+ * ubifs_calc_min_idx_lebs - calculate amount of LEBs for the index.
+ * @c: UBIFS file-system description object
+ *
+ * This function calculates and returns the number of LEBs which should be kept
+ * for index usage.
+ */
+int ubifs_calc_min_idx_lebs(struct ubifs_info *c)
+{
+	int idx_lebs;
+	long long idx_size;
+
+	idx_size = c->bi.old_idx_sz + c->bi.idx_growth + c->bi.uncommitted_idx;
+	/* And make sure we have thrice the index size of space reserved */
+	idx_size += idx_size << 1;
+	/*
+	 * We do not maintain 'old_idx_size' as 'old_idx_lebs'/'old_idx_bytes'
+	 * pair, nor similarly the two variables for the new index size, so we
+	 * have to do this costly 64-bit division on fast-path.
+	 */
+	idx_lebs = div_u64(idx_size + c->idx_leb_size - 1, c->idx_leb_size);
+	/*
+	 * The index head is not available for the in-the-gaps method, so add an
+	 * extra LEB to compensate.
+	 */
+	idx_lebs += 1;
+	if (idx_lebs < MIN_INDEX_LEBS)
+		idx_lebs = MIN_INDEX_LEBS;
+	return idx_lebs;
+}
+
+/**
+ * ubifs_calc_available - calculate available FS space.
+ * @c: UBIFS file-system description object
+ * @min_idx_lebs: minimum number of LEBs reserved for the index
+ *
+ * This function calculates and returns amount of FS space available for use.
+ */
+long long ubifs_calc_available(const struct ubifs_info *c, int min_idx_lebs)
+{
+	int subtract_lebs;
+	long long available;
+
+	available = c->main_bytes - c->lst.total_used;
+
+	/*
+	 * Now 'available' contains theoretically available flash space
+	 * assuming there is no index, so we have to subtract the space which
+	 * is reserved for the index.
+	 */
+	subtract_lebs = min_idx_lebs;
+
+	/* Take into account that GC reserves one LEB for its own needs */
+	subtract_lebs += 1;
+
+	/*
+	 * Since different write types go to different heads, we should
+	 * reserve one leb for each head.
+	 */
+	subtract_lebs += c->jhead_cnt;
+
+	/* We also reserve one LEB for deletions, which bypass budgeting */
+	subtract_lebs += 1;
+
+	available -= (long long)subtract_lebs * c->leb_size;
+
+	/* Subtract the dead space which is not available for use */
+	available -= c->lst.total_dead;
+
+	/*
+	 * Subtract dark space, which might or might not be usable - it depends
+	 * on the data which we have on the media and which will be written. If
+	 * this is a lot of uncompressed or not-compressible data, the dark
+	 * space cannot be used.
+	 */
+	available -= c->lst.total_dark;
+
+	/*
+	 * However, there is more dark space. The index may be bigger than
+	 * @min_idx_lebs. Those extra LEBs are assumed to be available, but
+	 * their dark space is not included in total_dark, so it is subtracted
+	 * here.
+	 */
+	if (c->lst.idx_lebs > min_idx_lebs) {
+		subtract_lebs = c->lst.idx_lebs - min_idx_lebs;
+		available -= subtract_lebs * c->dark_wm;
+	}
+
+	/* The calculations are rough and may end up with a negative number */
+	return available > 0 ? available : 0;
+}
+
+/**
+ * can_use_rp - check whether the user is allowed to use reserved pool.
+ * @c: UBIFS file-system description object
+ *
+ * UBIFS has so-called "reserved pool" which is flash space reserved
+ * for the superuser and for uses whose UID/GID is recorded in UBIFS superblock.
+ * This function checks whether current user is allowed to use reserved pool.
+ * Returns %1  current user is allowed to use reserved pool and %0 otherwise.
+ */
+static int can_use_rp(struct ubifs_info *c)
+{
+	if (uid_eq(current_fsuid(), c->rp_uid) || capable(CAP_SYS_RESOURCE) ||
+	    (!gid_eq(c->rp_gid, GLOBAL_ROOT_GID) && in_group_p(c->rp_gid)))
+		return 1;
+	return 0;
+}
+
+/**
+ * do_budget_space - reserve flash space for index and data growth.
+ * @c: UBIFS file-system description object
+ *
+ * This function makes sure UBIFS has enough free LEBs for index growth and
+ * data.
+ *
+ * When budgeting index space, UBIFS reserves thrice as many LEBs as the index
+ * would take if it was consolidated and written to the flash. This guarantees
+ * that the "in-the-gaps" commit method always succeeds and UBIFS will always
+ * be able to commit dirty index. So this function basically adds amount of
+ * budgeted index space to the size of the current index, multiplies this by 3,
+ * and makes sure this does not exceed the amount of free LEBs.
+ *
+ * Notes about @c->bi.min_idx_lebs and @c->lst.idx_lebs variables:
+ * o @c->lst.idx_lebs is the number of LEBs the index currently uses. It might
+ *    be large, because UBIFS does not do any index consolidation as long as
+ *    there is free space. IOW, the index may take a lot of LEBs, but the LEBs
+ *    will contain a lot of dirt.
+ * o @c->bi.min_idx_lebs is the number of LEBS the index presumably takes. IOW,
+ *    the index may be consolidated to take up to @c->bi.min_idx_lebs LEBs.
+ *
+ * This function returns zero in case of success, and %-ENOSPC in case of
+ * failure.
+ */
+static int do_budget_space(struct ubifs_info *c)
+{
+	long long outstanding, available;
+	int lebs, rsvd_idx_lebs, min_idx_lebs;
+
+	/* First budget index space */
+	min_idx_lebs = ubifs_calc_min_idx_lebs(c);
+
+	/* Now 'min_idx_lebs' contains number of LEBs to reserve */
+	if (min_idx_lebs > c->lst.idx_lebs)
+		rsvd_idx_lebs = min_idx_lebs - c->lst.idx_lebs;
+	else
+		rsvd_idx_lebs = 0;
+
+	/*
+	 * The number of LEBs that are available to be used by the index is:
+	 *
+	 *    @c->lst.empty_lebs + @c->freeable_cnt + @c->idx_gc_cnt -
+	 *    @c->lst.taken_empty_lebs
+	 *
+	 * @c->lst.empty_lebs are available because they are empty.
+	 * @c->freeable_cnt are available because they contain only free and
+	 * dirty space, @c->idx_gc_cnt are available because they are index
+	 * LEBs that have been garbage collected and are awaiting the commit
+	 * before they can be used. And the in-the-gaps method will grab these
+	 * if it needs them. @c->lst.taken_empty_lebs are empty LEBs that have
+	 * already been allocated for some purpose.
+	 *
+	 * Note, @c->idx_gc_cnt is included to both @c->lst.empty_lebs (because
+	 * these LEBs are empty) and to @c->lst.taken_empty_lebs (because they
+	 * are taken until after the commit).
+	 *
+	 * Note, @c->lst.taken_empty_lebs may temporarily be higher by one
+	 * because of the way we serialize LEB allocations and budgeting. See a
+	 * comment in 'ubifs_find_free_space()'.
+	 */
+	lebs = c->lst.empty_lebs + c->freeable_cnt + c->idx_gc_cnt -
+	       c->lst.taken_empty_lebs;
+	if (unlikely(rsvd_idx_lebs > lebs)) {
+		dbg_budg("out of indexing space: min_idx_lebs %d (old %d), rsvd_idx_lebs %d",
+			 min_idx_lebs, c->bi.min_idx_lebs, rsvd_idx_lebs);
+		return -ENOSPC;
+	}
+
+	available = ubifs_calc_available(c, min_idx_lebs);
+	outstanding = c->bi.data_growth + c->bi.dd_growth;
+
+	if (unlikely(available < outstanding)) {
+		dbg_budg("out of data space: available %lld, outstanding %lld",
+			 available, outstanding);
+		return -ENOSPC;
+	}
+
+	if (available - outstanding <= c->rp_size && !can_use_rp(c))
+		return -ENOSPC;
+
+	c->bi.min_idx_lebs = min_idx_lebs;
+	return 0;
+}
+
+/**
+ * calc_idx_growth - calculate approximate index growth from budgeting request.
+ * @c: UBIFS file-system description object
+ * @req: budgeting request
+ *
+ * For now we assume each new node adds one znode. But this is rather poor
+ * approximation, though.
+ */
+static int calc_idx_growth(const struct ubifs_info *c,
+			   const struct ubifs_budget_req *req)
+{
+	int znodes;
+
+	znodes = req->new_ino + (req->new_page << UBIFS_BLOCKS_PER_PAGE_SHIFT) +
+		 req->new_dent;
+	return znodes * c->max_idx_node_sz;
+}
+
+/**
+ * calc_data_growth - calculate approximate amount of new data from budgeting
+ * request.
+ * @c: UBIFS file-system description object
+ * @req: budgeting request
+ */
+static int calc_data_growth(const struct ubifs_info *c,
+			    const struct ubifs_budget_req *req)
+{
+	int data_growth;
+
+	data_growth = req->new_ino  ? c->bi.inode_budget : 0;
+	if (req->new_page)
+		data_growth += c->bi.page_budget;
+	if (req->new_dent)
+		data_growth += c->bi.dent_budget;
+	data_growth += req->new_ino_d;
+	return data_growth;
+}
+
+/**
+ * calc_dd_growth - calculate approximate amount of data which makes other data
+ * dirty from budgeting request.
+ * @c: UBIFS file-system description object
+ * @req: budgeting request
+ */
+static int calc_dd_growth(const struct ubifs_info *c,
+			  const struct ubifs_budget_req *req)
+{
+	int dd_growth;
+
+	dd_growth = req->dirtied_page ? c->bi.page_budget : 0;
+
+	if (req->dirtied_ino)
+		dd_growth += c->bi.inode_budget * req->dirtied_ino;
+	if (req->mod_dent)
+		dd_growth += c->bi.dent_budget;
+	dd_growth += req->dirtied_ino_d;
+	return dd_growth;
+}
+
+/**
+ * ubifs_budget_space - ensure there is enough space to complete an operation.
+ * @c: UBIFS file-system description object
+ * @req: budget request
+ *
+ * This function allocates budget for an operation. It uses pessimistic
+ * approximation of how much flash space the operation needs. The goal of this
+ * function is to make sure UBIFS always has flash space to flush all dirty
+ * pages, dirty inodes, and dirty znodes (liability). This function may force
+ * commit, garbage-collection or write-back. Returns zero in case of success,
+ * %-ENOSPC if there is no free space and other negative error codes in case of
+ * failures.
+ */
+int ubifs_budget_space(struct ubifs_info *c, struct ubifs_budget_req *req)
+{
+	int err, idx_growth, data_growth, dd_growth, retried = 0;
+
+	ubifs_assert(c, req->new_page <= 1);
+	ubifs_assert(c, req->dirtied_page <= 1);
+	ubifs_assert(c, req->new_dent <= 1);
+	ubifs_assert(c, req->mod_dent <= 1);
+	ubifs_assert(c, req->new_ino <= 1);
+	ubifs_assert(c, req->new_ino_d <= UBIFS_MAX_INO_DATA);
+	ubifs_assert(c, req->dirtied_ino <= 4);
+	ubifs_assert(c, req->dirtied_ino_d <= UBIFS_MAX_INO_DATA * 4);
+	ubifs_assert(c, !(req->new_ino_d & 7));
+	ubifs_assert(c, !(req->dirtied_ino_d & 7));
+
+	data_growth = calc_data_growth(c, req);
+	dd_growth = calc_dd_growth(c, req);
+	if (!data_growth && !dd_growth)
+		return 0;
+	idx_growth = calc_idx_growth(c, req);
+
+again:
+	spin_lock(&c->space_lock);
+	ubifs_assert(c, c->bi.idx_growth >= 0);
+	ubifs_assert(c, c->bi.data_growth >= 0);
+	ubifs_assert(c, c->bi.dd_growth >= 0);
+
+	if (unlikely(c->bi.nospace) && (c->bi.nospace_rp || !can_use_rp(c))) {
+		dbg_budg("no space");
+		spin_unlock(&c->space_lock);
+		return -ENOSPC;
+	}
+
+	c->bi.idx_growth += idx_growth;
+	c->bi.data_growth += data_growth;
+	c->bi.dd_growth += dd_growth;
+
+	err = do_budget_space(c);
+	if (likely(!err)) {
+		req->idx_growth = idx_growth;
+		req->data_growth = data_growth;
+		req->dd_growth = dd_growth;
+		spin_unlock(&c->space_lock);
+		return 0;
+	}
+
+	/* Restore the old values */
+	c->bi.idx_growth -= idx_growth;
+	c->bi.data_growth -= data_growth;
+	c->bi.dd_growth -= dd_growth;
+	spin_unlock(&c->space_lock);
+
+	if (req->fast) {
+		dbg_budg("no space for fast budgeting");
+		return err;
+	}
+
+	err = make_free_space(c);
+	cond_resched();
+	if (err == -EAGAIN) {
+		dbg_budg("try again");
+		goto again;
+	} else if (err == -ENOSPC) {
+		if (!retried) {
+			retried = 1;
+			dbg_budg("-ENOSPC, but anyway try once again");
+			goto again;
+		}
+		dbg_budg("FS is full, -ENOSPC");
+		c->bi.nospace = 1;
+		if (can_use_rp(c) || c->rp_size == 0)
+			c->bi.nospace_rp = 1;
+		smp_wmb();
+	} else
+		ubifs_err(c, "cannot budget space, error %d", err);
+	return err;
+}
+
+/**
+ * ubifs_release_budget - release budgeted free space.
+ * @c: UBIFS file-system description object
+ * @req: budget request
+ *
+ * This function releases the space budgeted by 'ubifs_budget_space()'. Note,
+ * since the index changes (which were budgeted for in @req->idx_growth) will
+ * only be written to the media on commit, this function moves the index budget
+ * from @c->bi.idx_growth to @c->bi.uncommitted_idx. The latter will be zeroed
+ * by the commit operation.
+ */
+void ubifs_release_budget(struct ubifs_info *c, struct ubifs_budget_req *req)
+{
+	ubifs_assert(c, req->new_page <= 1);
+	ubifs_assert(c, req->dirtied_page <= 1);
+	ubifs_assert(c, req->new_dent <= 1);
+	ubifs_assert(c, req->mod_dent <= 1);
+	ubifs_assert(c, req->new_ino <= 1);
+	ubifs_assert(c, req->new_ino_d <= UBIFS_MAX_INO_DATA);
+	ubifs_assert(c, req->dirtied_ino <= 4);
+	ubifs_assert(c, req->dirtied_ino_d <= UBIFS_MAX_INO_DATA * 4);
+	ubifs_assert(c, !(req->new_ino_d & 7));
+	ubifs_assert(c, !(req->dirtied_ino_d & 7));
+	if (!req->recalculate) {
+		ubifs_assert(c, req->idx_growth >= 0);
+		ubifs_assert(c, req->data_growth >= 0);
+		ubifs_assert(c, req->dd_growth >= 0);
+	}
+
+	if (req->recalculate) {
+		req->data_growth = calc_data_growth(c, req);
+		req->dd_growth = calc_dd_growth(c, req);
+		req->idx_growth = calc_idx_growth(c, req);
+	}
+
+	if (!req->data_growth && !req->dd_growth)
+		return;
+
+	c->bi.nospace = c->bi.nospace_rp = 0;
+	smp_wmb();
+
+	spin_lock(&c->space_lock);
+	c->bi.idx_growth -= req->idx_growth;
+	c->bi.uncommitted_idx += req->idx_growth;
+	c->bi.data_growth -= req->data_growth;
+	c->bi.dd_growth -= req->dd_growth;
+	c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
+
+	ubifs_assert(c, c->bi.idx_growth >= 0);
+	ubifs_assert(c, c->bi.data_growth >= 0);
+	ubifs_assert(c, c->bi.dd_growth >= 0);
+	ubifs_assert(c, c->bi.min_idx_lebs < c->main_lebs);
+	ubifs_assert(c, !(c->bi.idx_growth & 7));
+	ubifs_assert(c, !(c->bi.data_growth & 7));
+	ubifs_assert(c, !(c->bi.dd_growth & 7));
+	spin_unlock(&c->space_lock);
+}
+
+/**
+ * ubifs_convert_page_budget - convert budget of a new page.
+ * @c: UBIFS file-system description object
+ *
+ * This function converts budget which was allocated for a new page of data to
+ * the budget of changing an existing page of data. The latter is smaller than
+ * the former, so this function only does simple re-calculation and does not
+ * involve any write-back.
+ */
+void ubifs_convert_page_budget(struct ubifs_info *c)
+{
+	spin_lock(&c->space_lock);
+	/* Release the index growth reservation */
+	c->bi.idx_growth -= c->max_idx_node_sz << UBIFS_BLOCKS_PER_PAGE_SHIFT;
+	/* Release the data growth reservation */
+	c->bi.data_growth -= c->bi.page_budget;
+	/* Increase the dirty data growth reservation instead */
+	c->bi.dd_growth += c->bi.page_budget;
+	/* And re-calculate the indexing space reservation */
+	c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
+	spin_unlock(&c->space_lock);
+}
+
+/**
+ * ubifs_release_dirty_inode_budget - release dirty inode budget.
+ * @c: UBIFS file-system description object
+ * @ui: UBIFS inode to release the budget for
+ *
+ * This function releases budget corresponding to a dirty inode. It is usually
+ * called when after the inode has been written to the media and marked as
+ * clean. It also causes the "no space" flags to be cleared.
+ */
+void ubifs_release_dirty_inode_budget(struct ubifs_info *c,
+				      struct ubifs_inode *ui)
+{
+	struct ubifs_budget_req req;
+
+	memset(&req, 0, sizeof(struct ubifs_budget_req));
+	/* The "no space" flags will be cleared because dd_growth is > 0 */
+	req.dd_growth = c->bi.inode_budget + ALIGN(ui->data_len, 8);
+	ubifs_release_budget(c, &req);
+}
+
+/**
+ * ubifs_reported_space - calculate reported free space.
+ * @c: the UBIFS file-system description object
+ * @free: amount of free space
+ *
+ * This function calculates amount of free space which will be reported to
+ * user-space. User-space application tend to expect that if the file-system
+ * (e.g., via the 'statfs()' call) reports that it has N bytes available, they
+ * are able to write a file of size N. UBIFS attaches node headers to each data
+ * node and it has to write indexing nodes as well. This introduces additional
+ * overhead, and UBIFS has to report slightly less free space to meet the above
+ * expectations.
+ *
+ * This function assumes free space is made up of uncompressed data nodes and
+ * full index nodes (one per data node, tripled because we always allow enough
+ * space to write the index thrice).
+ *
+ * Note, the calculation is pessimistic, which means that most of the time
+ * UBIFS reports less space than it actually has.
+ */
+long long ubifs_reported_space(const struct ubifs_info *c, long long free)
+{
+	int divisor, factor, f;
+
+	/*
+	 * Reported space size is @free * X, where X is UBIFS block size
+	 * divided by UBIFS block size + all overhead one data block
+	 * introduces. The overhead is the node header + indexing overhead.
+	 *
+	 * Indexing overhead calculations are based on the following formula:
+	 * I = N/(f - 1) + 1, where I - number of indexing nodes, N - number
+	 * of data nodes, f - fanout. Because effective UBIFS fanout is twice
+	 * as less than maximum fanout, we assume that each data node
+	 * introduces 3 * @c->max_idx_node_sz / (@c->fanout/2 - 1) bytes.
+	 * Note, the multiplier 3 is because UBIFS reserves thrice as more space
+	 * for the index.
+	 */
+	f = c->fanout > 3 ? c->fanout >> 1 : 2;
+	factor = UBIFS_BLOCK_SIZE;
+	divisor = UBIFS_MAX_DATA_NODE_SZ;
+	divisor += (c->max_idx_node_sz * 3) / (f - 1);
+	free *= factor;
+	return div_u64(free, divisor);
+}
+
+/**
+ * ubifs_get_free_space_nolock - return amount of free space.
+ * @c: UBIFS file-system description object
+ *
+ * This function calculates amount of free space to report to user-space.
+ *
+ * Because UBIFS may introduce substantial overhead (the index, node headers,
+ * alignment, wastage at the end of LEBs, etc), it cannot report real amount of
+ * free flash space it has (well, because not all dirty space is reclaimable,
+ * UBIFS does not actually know the real amount). If UBIFS did so, it would
+ * bread user expectations about what free space is. Users seem to accustomed
+ * to assume that if the file-system reports N bytes of free space, they would
+ * be able to fit a file of N bytes to the FS. This almost works for
+ * traditional file-systems, because they have way less overhead than UBIFS.
+ * So, to keep users happy, UBIFS tries to take the overhead into account.
+ */
+long long ubifs_get_free_space_nolock(struct ubifs_info *c)
+{
+	int rsvd_idx_lebs, lebs;
+	long long available, outstanding, free;
+
+	ubifs_assert(c, c->bi.min_idx_lebs == ubifs_calc_min_idx_lebs(c));
+	outstanding = c->bi.data_growth + c->bi.dd_growth;
+	available = ubifs_calc_available(c, c->bi.min_idx_lebs);
+
+	/*
+	 * When reporting free space to user-space, UBIFS guarantees that it is
+	 * possible to write a file of free space size. This means that for
+	 * empty LEBs we may use more precise calculations than
+	 * 'ubifs_calc_available()' is using. Namely, we know that in empty
+	 * LEBs we would waste only @c->leb_overhead bytes, not @c->dark_wm.
+	 * Thus, amend the available space.
+	 *
+	 * Note, the calculations below are similar to what we have in
+	 * 'do_budget_space()', so refer there for comments.
+	 */
+	if (c->bi.min_idx_lebs > c->lst.idx_lebs)
+		rsvd_idx_lebs = c->bi.min_idx_lebs - c->lst.idx_lebs;
+	else
+		rsvd_idx_lebs = 0;
+	lebs = c->lst.empty_lebs + c->freeable_cnt + c->idx_gc_cnt -
+	       c->lst.taken_empty_lebs;
+	lebs -= rsvd_idx_lebs;
+	available += lebs * (c->dark_wm - c->leb_overhead);
+
+	if (available > outstanding)
+		free = ubifs_reported_space(c, available - outstanding);
+	else
+		free = 0;
+	return free;
+}
+
+/**
+ * ubifs_get_free_space - return amount of free space.
+ * @c: UBIFS file-system description object
+ *
+ * This function calculates and returns amount of free space to report to
+ * user-space.
+ */
+long long ubifs_get_free_space(struct ubifs_info *c)
+{
+	long long free;
+
+	spin_lock(&c->space_lock);
+	free = ubifs_get_free_space_nolock(c);
+	spin_unlock(&c->space_lock);
+
+	return free;
+}
diff --git a/ubifs-utils/libubifs/commit.c b/ubifs-utils/libubifs/commit.c
new file mode 100644
index 00000000..5b3a8400
--- /dev/null
+++ b/ubifs-utils/libubifs/commit.c
@@ -0,0 +1,733 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file implements functions that manage the running of the commit process.
+ * Each affected module has its own functions to accomplish their part in the
+ * commit and those functions are called here.
+ *
+ * The commit is the process whereby all updates to the index and LEB properties
+ * are written out together and the journal becomes empty. This keeps the
+ * file system consistent - at all times the state can be recreated by reading
+ * the index and LEB properties and then replaying the journal.
+ *
+ * The commit is split into two parts named "commit start" and "commit end".
+ * During commit start, the commit process has exclusive access to the journal
+ * by holding the commit semaphore down for writing. As few I/O operations as
+ * possible are performed during commit start, instead the nodes that are to be
+ * written are merely identified. During commit end, the commit semaphore is no
+ * longer held and the journal is again in operation, allowing users to continue
+ * to use the file system while the bulk of the commit I/O is performed. The
+ * purpose of this two-step approach is to prevent the commit from causing any
+ * latency blips. Note that in any case, the commit does not prevent lookups
+ * (as permitted by the TNC mutex), or access to VFS data structures e.g. page
+ * cache.
+ */
+
+#include <linux/freezer.h>
+#include <linux/kthread.h>
+#include <linux/slab.h>
+#include "ubifs.h"
+
+/*
+ * nothing_to_commit - check if there is nothing to commit.
+ * @c: UBIFS file-system description object
+ *
+ * This is a helper function which checks if there is anything to commit. It is
+ * used as an optimization to avoid starting the commit if it is not really
+ * necessary. Indeed, the commit operation always assumes flash I/O (e.g.,
+ * writing the commit start node to the log), and it is better to avoid doing
+ * this unnecessarily. E.g., 'ubifs_sync_fs()' runs the commit, but if there is
+ * nothing to commit, it is more optimal to avoid any flash I/O.
+ *
+ * This function has to be called with @c->commit_sem locked for writing -
+ * this function does not take LPT/TNC locks because the @c->commit_sem
+ * guarantees that we have exclusive access to the TNC and LPT data structures.
+ *
+ * This function returns %1 if there is nothing to commit and %0 otherwise.
+ */
+static int nothing_to_commit(struct ubifs_info *c)
+{
+	/*
+	 * During mounting or remounting from R/O mode to R/W mode we may
+	 * commit for various recovery-related reasons.
+	 */
+	if (c->mounting || c->remounting_rw)
+		return 0;
+
+	/*
+	 * If the root TNC node is dirty, we definitely have something to
+	 * commit.
+	 */
+	if (c->zroot.znode && ubifs_zn_dirty(c->zroot.znode))
+		return 0;
+
+	/*
+	 * Increasing @c->dirty_pn_cnt/@c->dirty_nn_cnt and marking
+	 * nnodes/pnodes as dirty in run_gc() could race with following
+	 * checking, which leads inconsistent states between @c->nroot
+	 * and @c->dirty_pn_cnt/@c->dirty_nn_cnt, holding @c->lp_mutex
+	 * to avoid that.
+	 */
+	mutex_lock(&c->lp_mutex);
+	/*
+	 * Even though the TNC is clean, the LPT tree may have dirty nodes. For
+	 * example, this may happen if the budgeting subsystem invoked GC to
+	 * make some free space, and the GC found an LEB with only dirty and
+	 * free space. In this case GC would just change the lprops of this
+	 * LEB (by turning all space into free space) and unmap it.
+	 */
+	if (c->nroot && test_bit(DIRTY_CNODE, &c->nroot->flags)) {
+		mutex_unlock(&c->lp_mutex);
+		return 0;
+	}
+
+	ubifs_assert(c, atomic_long_read(&c->dirty_zn_cnt) == 0);
+	ubifs_assert(c, c->dirty_pn_cnt == 0);
+	ubifs_assert(c, c->dirty_nn_cnt == 0);
+	mutex_unlock(&c->lp_mutex);
+
+	return 1;
+}
+
+/**
+ * do_commit - commit the journal.
+ * @c: UBIFS file-system description object
+ *
+ * This function implements UBIFS commit. It has to be called with commit lock
+ * locked. Returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+static int do_commit(struct ubifs_info *c)
+{
+	int err, new_ltail_lnum, old_ltail_lnum, i;
+	struct ubifs_zbranch zroot;
+	struct ubifs_lp_stats lst;
+
+	dbg_cmt("start");
+	ubifs_assert(c, !c->ro_media && !c->ro_mount);
+
+	if (c->ro_error) {
+		err = -EROFS;
+		goto out_up;
+	}
+
+	if (nothing_to_commit(c)) {
+		up_write(&c->commit_sem);
+		err = 0;
+		goto out_cancel;
+	}
+
+	/* Sync all write buffers (necessary for recovery) */
+	for (i = 0; i < c->jhead_cnt; i++) {
+		err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
+		if (err)
+			goto out_up;
+	}
+
+	c->cmt_no += 1;
+	err = ubifs_gc_start_commit(c);
+	if (err)
+		goto out_up;
+	err = dbg_check_lprops(c);
+	if (err)
+		goto out_up;
+	err = ubifs_log_start_commit(c, &new_ltail_lnum);
+	if (err)
+		goto out_up;
+	err = ubifs_tnc_start_commit(c, &zroot);
+	if (err)
+		goto out_up;
+	err = ubifs_lpt_start_commit(c);
+	if (err)
+		goto out_up;
+	err = ubifs_orphan_start_commit(c);
+	if (err)
+		goto out_up;
+
+	ubifs_get_lp_stats(c, &lst);
+
+	up_write(&c->commit_sem);
+
+	err = ubifs_tnc_end_commit(c);
+	if (err)
+		goto out;
+	err = ubifs_lpt_end_commit(c);
+	if (err)
+		goto out;
+	err = ubifs_orphan_end_commit(c);
+	if (err)
+		goto out;
+	err = dbg_check_old_index(c, &zroot);
+	if (err)
+		goto out;
+
+	c->mst_node->cmt_no      = cpu_to_le64(c->cmt_no);
+	c->mst_node->log_lnum    = cpu_to_le32(new_ltail_lnum);
+	c->mst_node->root_lnum   = cpu_to_le32(zroot.lnum);
+	c->mst_node->root_offs   = cpu_to_le32(zroot.offs);
+	c->mst_node->root_len    = cpu_to_le32(zroot.len);
+	c->mst_node->ihead_lnum  = cpu_to_le32(c->ihead_lnum);
+	c->mst_node->ihead_offs  = cpu_to_le32(c->ihead_offs);
+	c->mst_node->index_size  = cpu_to_le64(c->bi.old_idx_sz);
+	c->mst_node->lpt_lnum    = cpu_to_le32(c->lpt_lnum);
+	c->mst_node->lpt_offs    = cpu_to_le32(c->lpt_offs);
+	c->mst_node->nhead_lnum  = cpu_to_le32(c->nhead_lnum);
+	c->mst_node->nhead_offs  = cpu_to_le32(c->nhead_offs);
+	c->mst_node->ltab_lnum   = cpu_to_le32(c->ltab_lnum);
+	c->mst_node->ltab_offs   = cpu_to_le32(c->ltab_offs);
+	c->mst_node->lsave_lnum  = cpu_to_le32(c->lsave_lnum);
+	c->mst_node->lsave_offs  = cpu_to_le32(c->lsave_offs);
+	c->mst_node->lscan_lnum  = cpu_to_le32(c->lscan_lnum);
+	c->mst_node->empty_lebs  = cpu_to_le32(lst.empty_lebs);
+	c->mst_node->idx_lebs    = cpu_to_le32(lst.idx_lebs);
+	c->mst_node->total_free  = cpu_to_le64(lst.total_free);
+	c->mst_node->total_dirty = cpu_to_le64(lst.total_dirty);
+	c->mst_node->total_used  = cpu_to_le64(lst.total_used);
+	c->mst_node->total_dead  = cpu_to_le64(lst.total_dead);
+	c->mst_node->total_dark  = cpu_to_le64(lst.total_dark);
+	if (c->no_orphs)
+		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
+	else
+		c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_NO_ORPHS);
+
+	old_ltail_lnum = c->ltail_lnum;
+	err = ubifs_log_end_commit(c, new_ltail_lnum);
+	if (err)
+		goto out;
+
+	err = ubifs_log_post_commit(c, old_ltail_lnum);
+	if (err)
+		goto out;
+	err = ubifs_gc_end_commit(c);
+	if (err)
+		goto out;
+	err = ubifs_lpt_post_commit(c);
+	if (err)
+		goto out;
+
+out_cancel:
+	spin_lock(&c->cs_lock);
+	c->cmt_state = COMMIT_RESTING;
+	wake_up(&c->cmt_wq);
+	dbg_cmt("commit end");
+	spin_unlock(&c->cs_lock);
+	return 0;
+
+out_up:
+	up_write(&c->commit_sem);
+out:
+	ubifs_err(c, "commit failed, error %d", err);
+	spin_lock(&c->cs_lock);
+	c->cmt_state = COMMIT_BROKEN;
+	wake_up(&c->cmt_wq);
+	spin_unlock(&c->cs_lock);
+	ubifs_ro_mode(c, err);
+	return err;
+}
+
+/**
+ * run_bg_commit - run background commit if it is needed.
+ * @c: UBIFS file-system description object
+ *
+ * This function runs background commit if it is needed. Returns zero in case
+ * of success and a negative error code in case of failure.
+ */
+static int run_bg_commit(struct ubifs_info *c)
+{
+	spin_lock(&c->cs_lock);
+	/*
+	 * Run background commit only if background commit was requested or if
+	 * commit is required.
+	 */
+	if (c->cmt_state != COMMIT_BACKGROUND &&
+	    c->cmt_state != COMMIT_REQUIRED)
+		goto out;
+	spin_unlock(&c->cs_lock);
+
+	down_write(&c->commit_sem);
+	spin_lock(&c->cs_lock);
+	if (c->cmt_state == COMMIT_REQUIRED)
+		c->cmt_state = COMMIT_RUNNING_REQUIRED;
+	else if (c->cmt_state == COMMIT_BACKGROUND)
+		c->cmt_state = COMMIT_RUNNING_BACKGROUND;
+	else
+		goto out_cmt_unlock;
+	spin_unlock(&c->cs_lock);
+
+	return do_commit(c);
+
+out_cmt_unlock:
+	up_write(&c->commit_sem);
+out:
+	spin_unlock(&c->cs_lock);
+	return 0;
+}
+
+/**
+ * ubifs_bg_thread - UBIFS background thread function.
+ * @info: points to the file-system description object
+ *
+ * This function implements various file-system background activities:
+ * o when a write-buffer timer expires it synchronizes the appropriate
+ *   write-buffer;
+ * o when the journal is about to be full, it starts in-advance commit.
+ *
+ * Note, other stuff like background garbage collection may be added here in
+ * future.
+ */
+int ubifs_bg_thread(void *info)
+{
+	int err;
+	struct ubifs_info *c = info;
+
+	ubifs_msg(c, "background thread \"%s\" started, PID %d",
+		  c->bgt_name, current->pid);
+	set_freezable();
+
+	while (1) {
+		if (kthread_should_stop())
+			break;
+
+		if (try_to_freeze())
+			continue;
+
+		set_current_state(TASK_INTERRUPTIBLE);
+		/* Check if there is something to do */
+		if (!c->need_bgt) {
+			/*
+			 * Nothing prevents us from going sleep now and
+			 * be never woken up and block the task which
+			 * could wait in 'kthread_stop()' forever.
+			 */
+			if (kthread_should_stop())
+				break;
+			schedule();
+			continue;
+		} else
+			__set_current_state(TASK_RUNNING);
+
+		c->need_bgt = 0;
+		err = ubifs_bg_wbufs_sync(c);
+		if (err)
+			ubifs_ro_mode(c, err);
+
+		run_bg_commit(c);
+		cond_resched();
+	}
+
+	ubifs_msg(c, "background thread \"%s\" stops", c->bgt_name);
+	return 0;
+}
+
+/**
+ * ubifs_commit_required - set commit state to "required".
+ * @c: UBIFS file-system description object
+ *
+ * This function is called if a commit is required but cannot be done from the
+ * calling function, so it is just flagged instead.
+ */
+void ubifs_commit_required(struct ubifs_info *c)
+{
+	spin_lock(&c->cs_lock);
+	switch (c->cmt_state) {
+	case COMMIT_RESTING:
+	case COMMIT_BACKGROUND:
+		dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
+			dbg_cstate(COMMIT_REQUIRED));
+		c->cmt_state = COMMIT_REQUIRED;
+		break;
+	case COMMIT_RUNNING_BACKGROUND:
+		dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
+			dbg_cstate(COMMIT_RUNNING_REQUIRED));
+		c->cmt_state = COMMIT_RUNNING_REQUIRED;
+		break;
+	case COMMIT_REQUIRED:
+	case COMMIT_RUNNING_REQUIRED:
+	case COMMIT_BROKEN:
+		break;
+	}
+	spin_unlock(&c->cs_lock);
+}
+
+/**
+ * ubifs_request_bg_commit - notify the background thread to do a commit.
+ * @c: UBIFS file-system description object
+ *
+ * This function is called if the journal is full enough to make a commit
+ * worthwhile, so background thread is kicked to start it.
+ */
+void ubifs_request_bg_commit(struct ubifs_info *c)
+{
+	spin_lock(&c->cs_lock);
+	if (c->cmt_state == COMMIT_RESTING) {
+		dbg_cmt("old: %s, new: %s", dbg_cstate(c->cmt_state),
+			dbg_cstate(COMMIT_BACKGROUND));
+		c->cmt_state = COMMIT_BACKGROUND;
+		spin_unlock(&c->cs_lock);
+		ubifs_wake_up_bgt(c);
+	} else
+		spin_unlock(&c->cs_lock);
+}
+
+/**
+ * wait_for_commit - wait for commit.
+ * @c: UBIFS file-system description object
+ *
+ * This function sleeps until the commit operation is no longer running.
+ */
+static int wait_for_commit(struct ubifs_info *c)
+{
+	dbg_cmt("pid %d goes sleep", current->pid);
+
+	/*
+	 * The following sleeps if the condition is false, and will be woken
+	 * when the commit ends. It is possible, although very unlikely, that we
+	 * will wake up and see the subsequent commit running, rather than the
+	 * one we were waiting for, and go back to sleep.  However, we will be
+	 * woken again, so there is no danger of sleeping forever.
+	 */
+	wait_event(c->cmt_wq, c->cmt_state != COMMIT_RUNNING_BACKGROUND &&
+			      c->cmt_state != COMMIT_RUNNING_REQUIRED);
+	dbg_cmt("commit finished, pid %d woke up", current->pid);
+	return 0;
+}
+
+/**
+ * ubifs_run_commit - run or wait for commit.
+ * @c: UBIFS file-system description object
+ *
+ * This function runs commit and returns zero in case of success and a negative
+ * error code in case of failure.
+ */
+int ubifs_run_commit(struct ubifs_info *c)
+{
+	int err = 0;
+
+	spin_lock(&c->cs_lock);
+	if (c->cmt_state == COMMIT_BROKEN) {
+		err = -EROFS;
+		goto out;
+	}
+
+	if (c->cmt_state == COMMIT_RUNNING_BACKGROUND)
+		/*
+		 * We set the commit state to 'running required' to indicate
+		 * that we want it to complete as quickly as possible.
+		 */
+		c->cmt_state = COMMIT_RUNNING_REQUIRED;
+
+	if (c->cmt_state == COMMIT_RUNNING_REQUIRED) {
+		spin_unlock(&c->cs_lock);
+		return wait_for_commit(c);
+	}
+	spin_unlock(&c->cs_lock);
+
+	/* Ok, the commit is indeed needed */
+
+	down_write(&c->commit_sem);
+	spin_lock(&c->cs_lock);
+	/*
+	 * Since we unlocked 'c->cs_lock', the state may have changed, so
+	 * re-check it.
+	 */
+	if (c->cmt_state == COMMIT_BROKEN) {
+		err = -EROFS;
+		goto out_cmt_unlock;
+	}
+
+	if (c->cmt_state == COMMIT_RUNNING_BACKGROUND)
+		c->cmt_state = COMMIT_RUNNING_REQUIRED;
+
+	if (c->cmt_state == COMMIT_RUNNING_REQUIRED) {
+		up_write(&c->commit_sem);
+		spin_unlock(&c->cs_lock);
+		return wait_for_commit(c);
+	}
+	c->cmt_state = COMMIT_RUNNING_REQUIRED;
+	spin_unlock(&c->cs_lock);
+
+	err = do_commit(c);
+	return err;
+
+out_cmt_unlock:
+	up_write(&c->commit_sem);
+out:
+	spin_unlock(&c->cs_lock);
+	return err;
+}
+
+/**
+ * ubifs_gc_should_commit - determine if it is time for GC to run commit.
+ * @c: UBIFS file-system description object
+ *
+ * This function is called by garbage collection to determine if commit should
+ * be run. If commit state is @COMMIT_BACKGROUND, which means that the journal
+ * is full enough to start commit, this function returns true. It is not
+ * absolutely necessary to commit yet, but it feels like this should be better
+ * then to keep doing GC. This function returns %1 if GC has to initiate commit
+ * and %0 if not.
+ */
+int ubifs_gc_should_commit(struct ubifs_info *c)
+{
+	int ret = 0;
+
+	spin_lock(&c->cs_lock);
+	if (c->cmt_state == COMMIT_BACKGROUND) {
+		dbg_cmt("commit required now");
+		c->cmt_state = COMMIT_REQUIRED;
+	} else
+		dbg_cmt("commit not requested");
+	if (c->cmt_state == COMMIT_REQUIRED)
+		ret = 1;
+	spin_unlock(&c->cs_lock);
+	return ret;
+}
+
+/*
+ * Everything below is related to debugging.
+ */
+
+/**
+ * struct idx_node - hold index nodes during index tree traversal.
+ * @list: list
+ * @iip: index in parent (slot number of this indexing node in the parent
+ *       indexing node)
+ * @upper_key: all keys in this indexing node have to be less or equivalent to
+ *             this key
+ * @idx: index node (8-byte aligned because all node structures must be 8-byte
+ *       aligned)
+ */
+struct idx_node {
+	struct list_head list;
+	int iip;
+	union ubifs_key upper_key;
+	struct ubifs_idx_node idx __aligned(8);
+};
+
+/**
+ * dbg_old_index_check_init - get information for the next old index check.
+ * @c: UBIFS file-system description object
+ * @zroot: root of the index
+ *
+ * This function records information about the index that will be needed for the
+ * next old index check i.e. 'dbg_check_old_index()'.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int dbg_old_index_check_init(struct ubifs_info *c, struct ubifs_zbranch *zroot)
+{
+	struct ubifs_idx_node *idx;
+	int lnum, offs, len, err = 0;
+	struct ubifs_debug_info *d = c->dbg;
+
+	d->old_zroot = *zroot;
+	lnum = d->old_zroot.lnum;
+	offs = d->old_zroot.offs;
+	len = d->old_zroot.len;
+
+	idx = kmalloc(c->max_idx_node_sz, GFP_NOFS);
+	if (!idx)
+		return -ENOMEM;
+
+	err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
+	if (err)
+		goto out;
+
+	d->old_zroot_level = le16_to_cpu(idx->level);
+	d->old_zroot_sqnum = le64_to_cpu(idx->ch.sqnum);
+out:
+	kfree(idx);
+	return err;
+}
+
+/**
+ * dbg_check_old_index - check the old copy of the index.
+ * @c: UBIFS file-system description object
+ * @zroot: root of the new index
+ *
+ * In order to be able to recover from an unclean unmount, a complete copy of
+ * the index must exist on flash. This is the "old" index. The commit process
+ * must write the "new" index to flash without overwriting or destroying any
+ * part of the old index. This function is run at commit end in order to check
+ * that the old index does indeed exist completely intact.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int dbg_check_old_index(struct ubifs_info *c, struct ubifs_zbranch *zroot)
+{
+	int lnum, offs, len, err = 0, last_level, child_cnt;
+	int first = 1, iip;
+	struct ubifs_debug_info *d = c->dbg;
+	union ubifs_key lower_key, upper_key, l_key, u_key;
+	unsigned long long last_sqnum;
+	struct ubifs_idx_node *idx;
+	struct list_head list;
+	struct idx_node *i;
+	size_t sz;
+
+	if (!dbg_is_chk_index(c))
+		return 0;
+
+	INIT_LIST_HEAD(&list);
+
+	sz = sizeof(struct idx_node) + ubifs_idx_node_sz(c, c->fanout) -
+	     UBIFS_IDX_NODE_SZ;
+
+	/* Start at the old zroot */
+	lnum = d->old_zroot.lnum;
+	offs = d->old_zroot.offs;
+	len = d->old_zroot.len;
+	iip = 0;
+
+	/*
+	 * Traverse the index tree preorder depth-first i.e. do a node and then
+	 * its subtrees from left to right.
+	 */
+	while (1) {
+		struct ubifs_branch *br;
+
+		/* Get the next index node */
+		i = kmalloc(sz, GFP_NOFS);
+		if (!i) {
+			err = -ENOMEM;
+			goto out_free;
+		}
+		i->iip = iip;
+		/* Keep the index nodes on our path in a linked list */
+		list_add_tail(&i->list, &list);
+		/* Read the index node */
+		idx = &i->idx;
+		err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
+		if (err)
+			goto out_free;
+		/* Validate index node */
+		child_cnt = le16_to_cpu(idx->child_cnt);
+		if (child_cnt < 1 || child_cnt > c->fanout) {
+			err = 1;
+			goto out_dump;
+		}
+		if (first) {
+			first = 0;
+			/* Check root level and sqnum */
+			if (le16_to_cpu(idx->level) != d->old_zroot_level) {
+				err = 2;
+				goto out_dump;
+			}
+			if (le64_to_cpu(idx->ch.sqnum) != d->old_zroot_sqnum) {
+				err = 3;
+				goto out_dump;
+			}
+			/* Set last values as though root had a parent */
+			last_level = le16_to_cpu(idx->level) + 1;
+			last_sqnum = le64_to_cpu(idx->ch.sqnum) + 1;
+			key_read(c, ubifs_idx_key(c, idx), &lower_key);
+			highest_ino_key(c, &upper_key, INUM_WATERMARK);
+		}
+		key_copy(c, &upper_key, &i->upper_key);
+		if (le16_to_cpu(idx->level) != last_level - 1) {
+			err = 3;
+			goto out_dump;
+		}
+		/*
+		 * The index is always written bottom up hence a child's sqnum
+		 * is always less than the parents.
+		 */
+		if (le64_to_cpu(idx->ch.sqnum) >= last_sqnum) {
+			err = 4;
+			goto out_dump;
+		}
+		/* Check key range */
+		key_read(c, ubifs_idx_key(c, idx), &l_key);
+		br = ubifs_idx_branch(c, idx, child_cnt - 1);
+		key_read(c, &br->key, &u_key);
+		if (keys_cmp(c, &lower_key, &l_key) > 0) {
+			err = 5;
+			goto out_dump;
+		}
+		if (keys_cmp(c, &upper_key, &u_key) < 0) {
+			err = 6;
+			goto out_dump;
+		}
+		if (keys_cmp(c, &upper_key, &u_key) == 0)
+			if (!is_hash_key(c, &u_key)) {
+				err = 7;
+				goto out_dump;
+			}
+		/* Go to next index node */
+		if (le16_to_cpu(idx->level) == 0) {
+			/* At the bottom, so go up until can go right */
+			while (1) {
+				/* Drop the bottom of the list */
+				list_del(&i->list);
+				kfree(i);
+				/* No more list means we are done */
+				if (list_empty(&list))
+					goto out;
+				/* Look at the new bottom */
+				i = list_entry(list.prev, struct idx_node,
+					       list);
+				idx = &i->idx;
+				/* Can we go right */
+				if (iip + 1 < le16_to_cpu(idx->child_cnt)) {
+					iip = iip + 1;
+					break;
+				} else
+					/* Nope, so go up again */
+					iip = i->iip;
+			}
+		} else
+			/* Go down left */
+			iip = 0;
+		/*
+		 * We have the parent in 'idx' and now we set up for reading the
+		 * child pointed to by slot 'iip'.
+		 */
+		last_level = le16_to_cpu(idx->level);
+		last_sqnum = le64_to_cpu(idx->ch.sqnum);
+		br = ubifs_idx_branch(c, idx, iip);
+		lnum = le32_to_cpu(br->lnum);
+		offs = le32_to_cpu(br->offs);
+		len = le32_to_cpu(br->len);
+		key_read(c, &br->key, &lower_key);
+		if (iip + 1 < le16_to_cpu(idx->child_cnt)) {
+			br = ubifs_idx_branch(c, idx, iip + 1);
+			key_read(c, &br->key, &upper_key);
+		} else
+			key_copy(c, &i->upper_key, &upper_key);
+	}
+out:
+	err = dbg_old_index_check_init(c, zroot);
+	if (err)
+		goto out_free;
+
+	return 0;
+
+out_dump:
+	ubifs_err(c, "dumping index node (iip=%d)", i->iip);
+	ubifs_dump_node(c, idx, ubifs_idx_node_sz(c, c->fanout));
+	list_del(&i->list);
+	kfree(i);
+	if (!list_empty(&list)) {
+		i = list_entry(list.prev, struct idx_node, list);
+		ubifs_err(c, "dumping parent index node");
+		ubifs_dump_node(c, &i->idx, ubifs_idx_node_sz(c, c->fanout));
+	}
+out_free:
+	while (!list_empty(&list)) {
+		i = list_entry(list.next, struct idx_node, list);
+		list_del(&i->list);
+		kfree(i);
+	}
+	ubifs_err(c, "failed, error %d", err);
+	if (err > 0)
+		err = -EINVAL;
+	return err;
+}
diff --git a/ubifs-utils/libubifs/debug.c b/ubifs-utils/libubifs/debug.c
new file mode 100644
index 00000000..ac77ac1f
--- /dev/null
+++ b/ubifs-utils/libubifs/debug.c
@@ -0,0 +1,3051 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ */
+
+/*
+ * This file implements most of the debugging stuff which is compiled in only
+ * when it is enabled. But some debugging check functions are implemented in
+ * corresponding subsystem, just because they are closely related and utilize
+ * various local functions of those subsystems.
+ */
+
+#include <linux/module.h>
+#include <linux/debugfs.h>
+#include <linux/math64.h>
+#include <linux/uaccess.h>
+#include <linux/random.h>
+#include <linux/ctype.h>
+#include "ubifs.h"
+
+static DEFINE_SPINLOCK(dbg_lock);
+
+static const char *get_key_fmt(int fmt)
+{
+	switch (fmt) {
+	case UBIFS_SIMPLE_KEY_FMT:
+		return "simple";
+	default:
+		return "unknown/invalid format";
+	}
+}
+
+static const char *get_key_hash(int hash)
+{
+	switch (hash) {
+	case UBIFS_KEY_HASH_R5:
+		return "R5";
+	case UBIFS_KEY_HASH_TEST:
+		return "test";
+	default:
+		return "unknown/invalid name hash";
+	}
+}
+
+static const char *get_key_type(int type)
+{
+	switch (type) {
+	case UBIFS_INO_KEY:
+		return "inode";
+	case UBIFS_DENT_KEY:
+		return "direntry";
+	case UBIFS_XENT_KEY:
+		return "xentry";
+	case UBIFS_DATA_KEY:
+		return "data";
+	case UBIFS_TRUN_KEY:
+		return "truncate";
+	default:
+		return "unknown/invalid key";
+	}
+}
+
+static const char *get_dent_type(int type)
+{
+	switch (type) {
+	case UBIFS_ITYPE_REG:
+		return "file";
+	case UBIFS_ITYPE_DIR:
+		return "dir";
+	case UBIFS_ITYPE_LNK:
+		return "symlink";
+	case UBIFS_ITYPE_BLK:
+		return "blkdev";
+	case UBIFS_ITYPE_CHR:
+		return "char dev";
+	case UBIFS_ITYPE_FIFO:
+		return "fifo";
+	case UBIFS_ITYPE_SOCK:
+		return "socket";
+	default:
+		return "unknown/invalid type";
+	}
+}
+
+const char *dbg_snprintf_key(const struct ubifs_info *c,
+			     const union ubifs_key *key, char *buffer, int len)
+{
+	char *p = buffer;
+	int type = key_type(c, key);
+
+	if (c->key_fmt == UBIFS_SIMPLE_KEY_FMT) {
+		switch (type) {
+		case UBIFS_INO_KEY:
+			len -= snprintf(p, len, "(%lu, %s)",
+					(unsigned long)key_inum(c, key),
+					get_key_type(type));
+			break;
+		case UBIFS_DENT_KEY:
+		case UBIFS_XENT_KEY:
+			len -= snprintf(p, len, "(%lu, %s, %#08x)",
+					(unsigned long)key_inum(c, key),
+					get_key_type(type), key_hash(c, key));
+			break;
+		case UBIFS_DATA_KEY:
+			len -= snprintf(p, len, "(%lu, %s, %u)",
+					(unsigned long)key_inum(c, key),
+					get_key_type(type), key_block(c, key));
+			break;
+		case UBIFS_TRUN_KEY:
+			len -= snprintf(p, len, "(%lu, %s)",
+					(unsigned long)key_inum(c, key),
+					get_key_type(type));
+			break;
+		default:
+			len -= snprintf(p, len, "(bad key type: %#08x, %#08x)",
+					key->u32[0], key->u32[1]);
+		}
+	} else
+		len -= snprintf(p, len, "bad key format %d", c->key_fmt);
+	ubifs_assert(c, len > 0);
+	return p;
+}
+
+const char *dbg_ntype(int type)
+{
+	switch (type) {
+	case UBIFS_PAD_NODE:
+		return "padding node";
+	case UBIFS_SB_NODE:
+		return "superblock node";
+	case UBIFS_MST_NODE:
+		return "master node";
+	case UBIFS_REF_NODE:
+		return "reference node";
+	case UBIFS_INO_NODE:
+		return "inode node";
+	case UBIFS_DENT_NODE:
+		return "direntry node";
+	case UBIFS_XENT_NODE:
+		return "xentry node";
+	case UBIFS_DATA_NODE:
+		return "data node";
+	case UBIFS_TRUN_NODE:
+		return "truncate node";
+	case UBIFS_IDX_NODE:
+		return "indexing node";
+	case UBIFS_CS_NODE:
+		return "commit start node";
+	case UBIFS_ORPH_NODE:
+		return "orphan node";
+	case UBIFS_AUTH_NODE:
+		return "auth node";
+	default:
+		return "unknown node";
+	}
+}
+
+static const char *dbg_gtype(int type)
+{
+	switch (type) {
+	case UBIFS_NO_NODE_GROUP:
+		return "no node group";
+	case UBIFS_IN_NODE_GROUP:
+		return "in node group";
+	case UBIFS_LAST_OF_NODE_GROUP:
+		return "last of node group";
+	default:
+		return "unknown";
+	}
+}
+
+const char *dbg_cstate(int cmt_state)
+{
+	switch (cmt_state) {
+	case COMMIT_RESTING:
+		return "commit resting";
+	case COMMIT_BACKGROUND:
+		return "background commit requested";
+	case COMMIT_REQUIRED:
+		return "commit required";
+	case COMMIT_RUNNING_BACKGROUND:
+		return "BACKGROUND commit running";
+	case COMMIT_RUNNING_REQUIRED:
+		return "commit running and required";
+	case COMMIT_BROKEN:
+		return "broken commit";
+	default:
+		return "unknown commit state";
+	}
+}
+
+const char *dbg_jhead(int jhead)
+{
+	switch (jhead) {
+	case GCHD:
+		return "0 (GC)";
+	case BASEHD:
+		return "1 (base)";
+	case DATAHD:
+		return "2 (data)";
+	default:
+		return "unknown journal head";
+	}
+}
+
+static void dump_ch(const struct ubifs_ch *ch)
+{
+	pr_err("\tmagic          %#x\n", le32_to_cpu(ch->magic));
+	pr_err("\tcrc            %#x\n", le32_to_cpu(ch->crc));
+	pr_err("\tnode_type      %d (%s)\n", ch->node_type,
+	       dbg_ntype(ch->node_type));
+	pr_err("\tgroup_type     %d (%s)\n", ch->group_type,
+	       dbg_gtype(ch->group_type));
+	pr_err("\tsqnum          %llu\n",
+	       (unsigned long long)le64_to_cpu(ch->sqnum));
+	pr_err("\tlen            %u\n", le32_to_cpu(ch->len));
+}
+
+void ubifs_dump_inode(struct ubifs_info *c, const struct inode *inode)
+{
+	const struct ubifs_inode *ui = ubifs_inode(inode);
+	struct fscrypt_name nm = {0};
+	union ubifs_key key;
+	struct ubifs_dent_node *dent, *pdent = NULL;
+	int count = 2;
+
+	pr_err("Dump in-memory inode:");
+	pr_err("\tinode          %lu\n", inode->i_ino);
+	pr_err("\tsize           %llu\n",
+	       (unsigned long long)i_size_read(inode));
+	pr_err("\tnlink          %u\n", inode->i_nlink);
+	pr_err("\tuid            %u\n", (unsigned int)i_uid_read(inode));
+	pr_err("\tgid            %u\n", (unsigned int)i_gid_read(inode));
+	pr_err("\tatime          %u.%u\n",
+	       (unsigned int) inode_get_atime_sec(inode),
+	       (unsigned int) inode_get_atime_nsec(inode));
+	pr_err("\tmtime          %u.%u\n",
+	       (unsigned int) inode_get_mtime_sec(inode),
+	       (unsigned int) inode_get_mtime_nsec(inode));
+	pr_err("\tctime          %u.%u\n",
+	       (unsigned int) inode_get_ctime_sec(inode),
+	       (unsigned int) inode_get_ctime_nsec(inode));
+	pr_err("\tcreat_sqnum    %llu\n", ui->creat_sqnum);
+	pr_err("\txattr_size     %u\n", ui->xattr_size);
+	pr_err("\txattr_cnt      %u\n", ui->xattr_cnt);
+	pr_err("\txattr_names    %u\n", ui->xattr_names);
+	pr_err("\tdirty          %u\n", ui->dirty);
+	pr_err("\txattr          %u\n", ui->xattr);
+	pr_err("\tbulk_read      %u\n", ui->bulk_read);
+	pr_err("\tsynced_i_size  %llu\n",
+	       (unsigned long long)ui->synced_i_size);
+	pr_err("\tui_size        %llu\n",
+	       (unsigned long long)ui->ui_size);
+	pr_err("\tflags          %d\n", ui->flags);
+	pr_err("\tcompr_type     %d\n", ui->compr_type);
+	pr_err("\tlast_page_read %lu\n", ui->last_page_read);
+	pr_err("\tread_in_a_row  %lu\n", ui->read_in_a_row);
+	pr_err("\tdata_len       %d\n", ui->data_len);
+
+	if (!S_ISDIR(inode->i_mode))
+		return;
+
+	pr_err("List of directory entries:\n");
+	ubifs_assert(c, !mutex_is_locked(&c->tnc_mutex));
+
+	lowest_dent_key(c, &key, inode->i_ino);
+	while (1) {
+		dent = ubifs_tnc_next_ent(c, &key, &nm);
+		if (IS_ERR(dent)) {
+			if (PTR_ERR(dent) != -ENOENT)
+				pr_err("error %ld\n", PTR_ERR(dent));
+			break;
+		}
+
+		pr_err("\t%d: inode %llu, type %s, len %d\n",
+		       count++, (unsigned long long) le64_to_cpu(dent->inum),
+		       get_dent_type(dent->type),
+		       le16_to_cpu(dent->nlen));
+
+		fname_name(&nm) = dent->name;
+		fname_len(&nm) = le16_to_cpu(dent->nlen);
+		kfree(pdent);
+		pdent = dent;
+		key_read(c, &dent->key, &key);
+	}
+	kfree(pdent);
+}
+
+void ubifs_dump_node(const struct ubifs_info *c, const void *node, int node_len)
+{
+	int i, n, type, safe_len, max_node_len, min_node_len;
+	union ubifs_key key;
+	const struct ubifs_ch *ch = node;
+	char key_buf[DBG_KEY_BUF_LEN];
+
+	/* If the magic is incorrect, just hexdump the first bytes */
+	if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC) {
+		pr_err("Not a node, first %zu bytes:", UBIFS_CH_SZ);
+		print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 32, 1,
+			       (void *)node, UBIFS_CH_SZ, 1);
+		return;
+	}
+
+	/* Skip dumping unknown type node */
+	type = ch->node_type;
+	if (type < 0 || type >= UBIFS_NODE_TYPES_CNT) {
+		pr_err("node type %d was not recognized\n", type);
+		return;
+	}
+
+	spin_lock(&dbg_lock);
+	dump_ch(node);
+
+	if (c->ranges[type].max_len == 0) {
+		max_node_len = min_node_len = c->ranges[type].len;
+	} else {
+		max_node_len = c->ranges[type].max_len;
+		min_node_len = c->ranges[type].min_len;
+	}
+	safe_len = le32_to_cpu(ch->len);
+	safe_len = safe_len > 0 ? safe_len : 0;
+	safe_len = min3(safe_len, max_node_len, node_len);
+	if (safe_len < min_node_len) {
+		pr_err("node len(%d) is too short for %s, left %d bytes:\n",
+		       safe_len, dbg_ntype(type),
+		       safe_len > UBIFS_CH_SZ ?
+		       safe_len - (int)UBIFS_CH_SZ : 0);
+		if (safe_len > UBIFS_CH_SZ)
+			print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 32, 1,
+				       (void *)node + UBIFS_CH_SZ,
+				       safe_len - UBIFS_CH_SZ, 0);
+		goto out_unlock;
+	}
+	if (safe_len != le32_to_cpu(ch->len))
+		pr_err("\ttruncated node length      %d\n", safe_len);
+
+	switch (type) {
+	case UBIFS_PAD_NODE:
+	{
+		const struct ubifs_pad_node *pad = node;
+
+		pr_err("\tpad_len        %u\n", le32_to_cpu(pad->pad_len));
+		break;
+	}
+	case UBIFS_SB_NODE:
+	{
+		const struct ubifs_sb_node *sup = node;
+		unsigned int sup_flags = le32_to_cpu(sup->flags);
+
+		pr_err("\tkey_hash       %d (%s)\n",
+		       (int)sup->key_hash, get_key_hash(sup->key_hash));
+		pr_err("\tkey_fmt        %d (%s)\n",
+		       (int)sup->key_fmt, get_key_fmt(sup->key_fmt));
+		pr_err("\tflags          %#x\n", sup_flags);
+		pr_err("\tbig_lpt        %u\n",
+		       !!(sup_flags & UBIFS_FLG_BIGLPT));
+		pr_err("\tspace_fixup    %u\n",
+		       !!(sup_flags & UBIFS_FLG_SPACE_FIXUP));
+		pr_err("\tmin_io_size    %u\n", le32_to_cpu(sup->min_io_size));
+		pr_err("\tleb_size       %u\n", le32_to_cpu(sup->leb_size));
+		pr_err("\tleb_cnt        %u\n", le32_to_cpu(sup->leb_cnt));
+		pr_err("\tmax_leb_cnt    %u\n", le32_to_cpu(sup->max_leb_cnt));
+		pr_err("\tmax_bud_bytes  %llu\n",
+		       (unsigned long long)le64_to_cpu(sup->max_bud_bytes));
+		pr_err("\tlog_lebs       %u\n", le32_to_cpu(sup->log_lebs));
+		pr_err("\tlpt_lebs       %u\n", le32_to_cpu(sup->lpt_lebs));
+		pr_err("\torph_lebs      %u\n", le32_to_cpu(sup->orph_lebs));
+		pr_err("\tjhead_cnt      %u\n", le32_to_cpu(sup->jhead_cnt));
+		pr_err("\tfanout         %u\n", le32_to_cpu(sup->fanout));
+		pr_err("\tlsave_cnt      %u\n", le32_to_cpu(sup->lsave_cnt));
+		pr_err("\tdefault_compr  %u\n",
+		       (int)le16_to_cpu(sup->default_compr));
+		pr_err("\trp_size        %llu\n",
+		       (unsigned long long)le64_to_cpu(sup->rp_size));
+		pr_err("\trp_uid         %u\n", le32_to_cpu(sup->rp_uid));
+		pr_err("\trp_gid         %u\n", le32_to_cpu(sup->rp_gid));
+		pr_err("\tfmt_version    %u\n", le32_to_cpu(sup->fmt_version));
+		pr_err("\ttime_gran      %u\n", le32_to_cpu(sup->time_gran));
+		pr_err("\tUUID           %pUB\n", sup->uuid);
+		break;
+	}
+	case UBIFS_MST_NODE:
+	{
+		const struct ubifs_mst_node *mst = node;
+
+		pr_err("\thighest_inum   %llu\n",
+		       (unsigned long long)le64_to_cpu(mst->highest_inum));
+		pr_err("\tcommit number  %llu\n",
+		       (unsigned long long)le64_to_cpu(mst->cmt_no));
+		pr_err("\tflags          %#x\n", le32_to_cpu(mst->flags));
+		pr_err("\tlog_lnum       %u\n", le32_to_cpu(mst->log_lnum));
+		pr_err("\troot_lnum      %u\n", le32_to_cpu(mst->root_lnum));
+		pr_err("\troot_offs      %u\n", le32_to_cpu(mst->root_offs));
+		pr_err("\troot_len       %u\n", le32_to_cpu(mst->root_len));
+		pr_err("\tgc_lnum        %u\n", le32_to_cpu(mst->gc_lnum));
+		pr_err("\tihead_lnum     %u\n", le32_to_cpu(mst->ihead_lnum));
+		pr_err("\tihead_offs     %u\n", le32_to_cpu(mst->ihead_offs));
+		pr_err("\tindex_size     %llu\n",
+		       (unsigned long long)le64_to_cpu(mst->index_size));
+		pr_err("\tlpt_lnum       %u\n", le32_to_cpu(mst->lpt_lnum));
+		pr_err("\tlpt_offs       %u\n", le32_to_cpu(mst->lpt_offs));
+		pr_err("\tnhead_lnum     %u\n", le32_to_cpu(mst->nhead_lnum));
+		pr_err("\tnhead_offs     %u\n", le32_to_cpu(mst->nhead_offs));
+		pr_err("\tltab_lnum      %u\n", le32_to_cpu(mst->ltab_lnum));
+		pr_err("\tltab_offs      %u\n", le32_to_cpu(mst->ltab_offs));
+		pr_err("\tlsave_lnum     %u\n", le32_to_cpu(mst->lsave_lnum));
+		pr_err("\tlsave_offs     %u\n", le32_to_cpu(mst->lsave_offs));
+		pr_err("\tlscan_lnum     %u\n", le32_to_cpu(mst->lscan_lnum));
+		pr_err("\tleb_cnt        %u\n", le32_to_cpu(mst->leb_cnt));
+		pr_err("\tempty_lebs     %u\n", le32_to_cpu(mst->empty_lebs));
+		pr_err("\tidx_lebs       %u\n", le32_to_cpu(mst->idx_lebs));
+		pr_err("\ttotal_free     %llu\n",
+		       (unsigned long long)le64_to_cpu(mst->total_free));
+		pr_err("\ttotal_dirty    %llu\n",
+		       (unsigned long long)le64_to_cpu(mst->total_dirty));
+		pr_err("\ttotal_used     %llu\n",
+		       (unsigned long long)le64_to_cpu(mst->total_used));
+		pr_err("\ttotal_dead     %llu\n",
+		       (unsigned long long)le64_to_cpu(mst->total_dead));
+		pr_err("\ttotal_dark     %llu\n",
+		       (unsigned long long)le64_to_cpu(mst->total_dark));
+		break;
+	}
+	case UBIFS_REF_NODE:
+	{
+		const struct ubifs_ref_node *ref = node;
+
+		pr_err("\tlnum           %u\n", le32_to_cpu(ref->lnum));
+		pr_err("\toffs           %u\n", le32_to_cpu(ref->offs));
+		pr_err("\tjhead          %u\n", le32_to_cpu(ref->jhead));
+		break;
+	}
+	case UBIFS_INO_NODE:
+	{
+		const struct ubifs_ino_node *ino = node;
+
+		key_read(c, &ino->key, &key);
+		pr_err("\tkey            %s\n",
+		       dbg_snprintf_key(c, &key, key_buf, DBG_KEY_BUF_LEN));
+		pr_err("\tcreat_sqnum    %llu\n",
+		       (unsigned long long)le64_to_cpu(ino->creat_sqnum));
+		pr_err("\tsize           %llu\n",
+		       (unsigned long long)le64_to_cpu(ino->size));
+		pr_err("\tnlink          %u\n", le32_to_cpu(ino->nlink));
+		pr_err("\tatime          %lld.%u\n",
+		       (long long)le64_to_cpu(ino->atime_sec),
+		       le32_to_cpu(ino->atime_nsec));
+		pr_err("\tmtime          %lld.%u\n",
+		       (long long)le64_to_cpu(ino->mtime_sec),
+		       le32_to_cpu(ino->mtime_nsec));
+		pr_err("\tctime          %lld.%u\n",
+		       (long long)le64_to_cpu(ino->ctime_sec),
+		       le32_to_cpu(ino->ctime_nsec));
+		pr_err("\tuid            %u\n", le32_to_cpu(ino->uid));
+		pr_err("\tgid            %u\n", le32_to_cpu(ino->gid));
+		pr_err("\tmode           %u\n", le32_to_cpu(ino->mode));
+		pr_err("\tflags          %#x\n", le32_to_cpu(ino->flags));
+		pr_err("\txattr_cnt      %u\n", le32_to_cpu(ino->xattr_cnt));
+		pr_err("\txattr_size     %u\n", le32_to_cpu(ino->xattr_size));
+		pr_err("\txattr_names    %u\n", le32_to_cpu(ino->xattr_names));
+		pr_err("\tcompr_type     %#x\n",
+		       (int)le16_to_cpu(ino->compr_type));
+		pr_err("\tdata len       %u\n", le32_to_cpu(ino->data_len));
+		break;
+	}
+	case UBIFS_DENT_NODE:
+	case UBIFS_XENT_NODE:
+	{
+		const struct ubifs_dent_node *dent = node;
+		int nlen = le16_to_cpu(dent->nlen);
+
+		key_read(c, &dent->key, &key);
+		pr_err("\tkey            %s\n",
+		       dbg_snprintf_key(c, &key, key_buf, DBG_KEY_BUF_LEN));
+		pr_err("\tinum           %llu\n",
+		       (unsigned long long)le64_to_cpu(dent->inum));
+		pr_err("\ttype           %d\n", (int)dent->type);
+		pr_err("\tnlen           %d\n", nlen);
+		pr_err("\tname           ");
+
+		if (nlen > UBIFS_MAX_NLEN ||
+		    nlen > safe_len - UBIFS_DENT_NODE_SZ)
+			pr_err("(bad name length, not printing, bad or corrupted node)");
+		else {
+			for (i = 0; i < nlen && dent->name[i]; i++)
+				pr_cont("%c", isprint(dent->name[i]) ?
+					dent->name[i] : '?');
+		}
+		pr_cont("\n");
+
+		break;
+	}
+	case UBIFS_DATA_NODE:
+	{
+		const struct ubifs_data_node *dn = node;
+
+		key_read(c, &dn->key, &key);
+		pr_err("\tkey            %s\n",
+		       dbg_snprintf_key(c, &key, key_buf, DBG_KEY_BUF_LEN));
+		pr_err("\tsize           %u\n", le32_to_cpu(dn->size));
+		pr_err("\tcompr_typ      %d\n",
+		       (int)le16_to_cpu(dn->compr_type));
+		pr_err("\tdata size      %u\n",
+		       le32_to_cpu(ch->len) - (unsigned int)UBIFS_DATA_NODE_SZ);
+		pr_err("\tdata (length = %d):\n",
+		       safe_len - (int)UBIFS_DATA_NODE_SZ);
+		print_hex_dump(KERN_ERR, "\t", DUMP_PREFIX_OFFSET, 32, 1,
+			       (void *)&dn->data,
+			       safe_len - (int)UBIFS_DATA_NODE_SZ, 0);
+		break;
+	}
+	case UBIFS_TRUN_NODE:
+	{
+		const struct ubifs_trun_node *trun = node;
+
+		pr_err("\tinum           %u\n", le32_to_cpu(trun->inum));
+		pr_err("\told_size       %llu\n",
+		       (unsigned long long)le64_to_cpu(trun->old_size));
+		pr_err("\tnew_size       %llu\n",
+		       (unsigned long long)le64_to_cpu(trun->new_size));
+		break;
+	}
+	case UBIFS_IDX_NODE:
+	{
+		const struct ubifs_idx_node *idx = node;
+		int max_child_cnt = (safe_len - UBIFS_IDX_NODE_SZ) /
+				    (ubifs_idx_node_sz(c, 1) -
+				    UBIFS_IDX_NODE_SZ);
+
+		n = min_t(int, le16_to_cpu(idx->child_cnt), max_child_cnt);
+		pr_err("\tchild_cnt      %d\n", (int)le16_to_cpu(idx->child_cnt));
+		pr_err("\tlevel          %d\n", (int)le16_to_cpu(idx->level));
+		pr_err("\tBranches:\n");
+
+		for (i = 0; i < n && i < c->fanout; i++) {
+			const struct ubifs_branch *br;
+
+			br = ubifs_idx_branch(c, idx, i);
+			key_read(c, &br->key, &key);
+			pr_err("\t%d: LEB %d:%d len %d key %s\n",
+			       i, le32_to_cpu(br->lnum), le32_to_cpu(br->offs),
+			       le32_to_cpu(br->len),
+			       dbg_snprintf_key(c, &key, key_buf,
+						DBG_KEY_BUF_LEN));
+		}
+		break;
+	}
+	case UBIFS_CS_NODE:
+		break;
+	case UBIFS_ORPH_NODE:
+	{
+		const struct ubifs_orph_node *orph = node;
+
+		pr_err("\tcommit number  %llu\n",
+		       (unsigned long long)
+				le64_to_cpu(orph->cmt_no) & LLONG_MAX);
+		pr_err("\tlast node flag %llu\n",
+		       (unsigned long long)(le64_to_cpu(orph->cmt_no)) >> 63);
+		n = (safe_len - UBIFS_ORPH_NODE_SZ) >> 3;
+		pr_err("\t%d orphan inode numbers:\n", n);
+		for (i = 0; i < n; i++)
+			pr_err("\t  ino %llu\n",
+			       (unsigned long long)le64_to_cpu(orph->inos[i]));
+		break;
+	}
+	case UBIFS_AUTH_NODE:
+	{
+		break;
+	}
+	default:
+		pr_err("node type %d was not recognized\n", type);
+	}
+
+out_unlock:
+	spin_unlock(&dbg_lock);
+}
+
+void ubifs_dump_budget_req(const struct ubifs_budget_req *req)
+{
+	spin_lock(&dbg_lock);
+	pr_err("Budgeting request: new_ino %d, dirtied_ino %d\n",
+	       req->new_ino, req->dirtied_ino);
+	pr_err("\tnew_ino_d   %d, dirtied_ino_d %d\n",
+	       req->new_ino_d, req->dirtied_ino_d);
+	pr_err("\tnew_page    %d, dirtied_page %d\n",
+	       req->new_page, req->dirtied_page);
+	pr_err("\tnew_dent    %d, mod_dent     %d\n",
+	       req->new_dent, req->mod_dent);
+	pr_err("\tidx_growth  %d\n", req->idx_growth);
+	pr_err("\tdata_growth %d dd_growth     %d\n",
+	       req->data_growth, req->dd_growth);
+	spin_unlock(&dbg_lock);
+}
+
+void ubifs_dump_lstats(const struct ubifs_lp_stats *lst)
+{
+	spin_lock(&dbg_lock);
+	pr_err("(pid %d) Lprops statistics: empty_lebs %d, idx_lebs  %d\n",
+	       current->pid, lst->empty_lebs, lst->idx_lebs);
+	pr_err("\ttaken_empty_lebs %d, total_free %lld, total_dirty %lld\n",
+	       lst->taken_empty_lebs, lst->total_free, lst->total_dirty);
+	pr_err("\ttotal_used %lld, total_dark %lld, total_dead %lld\n",
+	       lst->total_used, lst->total_dark, lst->total_dead);
+	spin_unlock(&dbg_lock);
+}
+
+void ubifs_dump_budg(struct ubifs_info *c, const struct ubifs_budg_info *bi)
+{
+	int i;
+	struct rb_node *rb;
+	struct ubifs_bud *bud;
+	struct ubifs_gced_idx_leb *idx_gc;
+	long long available, outstanding, free;
+
+	spin_lock(&c->space_lock);
+	spin_lock(&dbg_lock);
+	pr_err("(pid %d) Budgeting info: data budget sum %lld, total budget sum %lld\n",
+	       current->pid, bi->data_growth + bi->dd_growth,
+	       bi->data_growth + bi->dd_growth + bi->idx_growth);
+	pr_err("\tbudg_data_growth %lld, budg_dd_growth %lld, budg_idx_growth %lld\n",
+	       bi->data_growth, bi->dd_growth, bi->idx_growth);
+	pr_err("\tmin_idx_lebs %d, old_idx_sz %llu, uncommitted_idx %lld\n",
+	       bi->min_idx_lebs, bi->old_idx_sz, bi->uncommitted_idx);
+	pr_err("\tpage_budget %d, inode_budget %d, dent_budget %d\n",
+	       bi->page_budget, bi->inode_budget, bi->dent_budget);
+	pr_err("\tnospace %u, nospace_rp %u\n", bi->nospace, bi->nospace_rp);
+	pr_err("\tdark_wm %d, dead_wm %d, max_idx_node_sz %d\n",
+	       c->dark_wm, c->dead_wm, c->max_idx_node_sz);
+
+	if (bi != &c->bi)
+		/*
+		 * If we are dumping saved budgeting data, do not print
+		 * additional information which is about the current state, not
+		 * the old one which corresponded to the saved budgeting data.
+		 */
+		goto out_unlock;
+
+	pr_err("\tfreeable_cnt %d, calc_idx_sz %lld, idx_gc_cnt %d\n",
+	       c->freeable_cnt, c->calc_idx_sz, c->idx_gc_cnt);
+	pr_err("\tdirty_pg_cnt %ld, dirty_zn_cnt %ld, clean_zn_cnt %ld\n",
+	       atomic_long_read(&c->dirty_pg_cnt),
+	       atomic_long_read(&c->dirty_zn_cnt),
+	       atomic_long_read(&c->clean_zn_cnt));
+	pr_err("\tgc_lnum %d, ihead_lnum %d\n", c->gc_lnum, c->ihead_lnum);
+
+	/* If we are in R/O mode, journal heads do not exist */
+	if (c->jheads)
+		for (i = 0; i < c->jhead_cnt; i++)
+			pr_err("\tjhead %s\t LEB %d\n",
+			       dbg_jhead(c->jheads[i].wbuf.jhead),
+			       c->jheads[i].wbuf.lnum);
+	for (rb = rb_first(&c->buds); rb; rb = rb_next(rb)) {
+		bud = rb_entry(rb, struct ubifs_bud, rb);
+		pr_err("\tbud LEB %d\n", bud->lnum);
+	}
+	list_for_each_entry(bud, &c->old_buds, list)
+		pr_err("\told bud LEB %d\n", bud->lnum);
+	list_for_each_entry(idx_gc, &c->idx_gc, list)
+		pr_err("\tGC'ed idx LEB %d unmap %d\n",
+		       idx_gc->lnum, idx_gc->unmap);
+	pr_err("\tcommit state %d\n", c->cmt_state);
+
+	/* Print budgeting predictions */
+	available = ubifs_calc_available(c, c->bi.min_idx_lebs);
+	outstanding = c->bi.data_growth + c->bi.dd_growth;
+	free = ubifs_get_free_space_nolock(c);
+	pr_err("Budgeting predictions:\n");
+	pr_err("\tavailable: %lld, outstanding %lld, free %lld\n",
+	       available, outstanding, free);
+out_unlock:
+	spin_unlock(&dbg_lock);
+	spin_unlock(&c->space_lock);
+}
+
+void ubifs_dump_lprop(const struct ubifs_info *c, const struct ubifs_lprops *lp)
+{
+	int i, spc, dark = 0, dead = 0;
+	struct rb_node *rb;
+	struct ubifs_bud *bud;
+
+	spc = lp->free + lp->dirty;
+	if (spc < c->dead_wm)
+		dead = spc;
+	else
+		dark = ubifs_calc_dark(c, spc);
+
+	if (lp->flags & LPROPS_INDEX)
+		pr_err("LEB %-7d free %-8d dirty %-8d used %-8d free + dirty %-8d flags %#x (",
+		       lp->lnum, lp->free, lp->dirty, c->leb_size - spc, spc,
+		       lp->flags);
+	else
+		pr_err("LEB %-7d free %-8d dirty %-8d used %-8d free + dirty %-8d dark %-4d dead %-4d nodes fit %-3d flags %#-4x (",
+		       lp->lnum, lp->free, lp->dirty, c->leb_size - spc, spc,
+		       dark, dead, (int)(spc / UBIFS_MAX_NODE_SZ), lp->flags);
+
+	if (lp->flags & LPROPS_TAKEN) {
+		if (lp->flags & LPROPS_INDEX)
+			pr_cont("index, taken");
+		else
+			pr_cont("taken");
+	} else {
+		const char *s;
+
+		if (lp->flags & LPROPS_INDEX) {
+			switch (lp->flags & LPROPS_CAT_MASK) {
+			case LPROPS_DIRTY_IDX:
+				s = "dirty index";
+				break;
+			case LPROPS_FRDI_IDX:
+				s = "freeable index";
+				break;
+			default:
+				s = "index";
+			}
+		} else {
+			switch (lp->flags & LPROPS_CAT_MASK) {
+			case LPROPS_UNCAT:
+				s = "not categorized";
+				break;
+			case LPROPS_DIRTY:
+				s = "dirty";
+				break;
+			case LPROPS_FREE:
+				s = "free";
+				break;
+			case LPROPS_EMPTY:
+				s = "empty";
+				break;
+			case LPROPS_FREEABLE:
+				s = "freeable";
+				break;
+			default:
+				s = NULL;
+				break;
+			}
+		}
+		pr_cont("%s", s);
+	}
+
+	for (rb = rb_first((struct rb_root *)&c->buds); rb; rb = rb_next(rb)) {
+		bud = rb_entry(rb, struct ubifs_bud, rb);
+		if (bud->lnum == lp->lnum) {
+			int head = 0;
+			for (i = 0; i < c->jhead_cnt; i++) {
+				/*
+				 * Note, if we are in R/O mode or in the middle
+				 * of mounting/re-mounting, the write-buffers do
+				 * not exist.
+				 */
+				if (c->jheads &&
+				    lp->lnum == c->jheads[i].wbuf.lnum) {
+					pr_cont(", jhead %s", dbg_jhead(i));
+					head = 1;
+				}
+			}
+			if (!head)
+				pr_cont(", bud of jhead %s",
+				       dbg_jhead(bud->jhead));
+		}
+	}
+	if (lp->lnum == c->gc_lnum)
+		pr_cont(", GC LEB");
+	pr_cont(")\n");
+}
+
+void ubifs_dump_lprops(struct ubifs_info *c)
+{
+	int lnum, err;
+	struct ubifs_lprops lp;
+	struct ubifs_lp_stats lst;
+
+	pr_err("(pid %d) start dumping LEB properties\n", current->pid);
+	ubifs_get_lp_stats(c, &lst);
+	ubifs_dump_lstats(&lst);
+
+	for (lnum = c->main_first; lnum < c->leb_cnt; lnum++) {
+		err = ubifs_read_one_lp(c, lnum, &lp);
+		if (err) {
+			ubifs_err(c, "cannot read lprops for LEB %d", lnum);
+			continue;
+		}
+
+		ubifs_dump_lprop(c, &lp);
+	}
+	pr_err("(pid %d) finish dumping LEB properties\n", current->pid);
+}
+
+void ubifs_dump_lpt_info(struct ubifs_info *c)
+{
+	int i;
+
+	spin_lock(&dbg_lock);
+	pr_err("(pid %d) dumping LPT information\n", current->pid);
+	pr_err("\tlpt_sz:        %lld\n", c->lpt_sz);
+	pr_err("\tpnode_sz:      %d\n", c->pnode_sz);
+	pr_err("\tnnode_sz:      %d\n", c->nnode_sz);
+	pr_err("\tltab_sz:       %d\n", c->ltab_sz);
+	pr_err("\tlsave_sz:      %d\n", c->lsave_sz);
+	pr_err("\tbig_lpt:       %u\n", c->big_lpt);
+	pr_err("\tlpt_hght:      %d\n", c->lpt_hght);
+	pr_err("\tpnode_cnt:     %d\n", c->pnode_cnt);
+	pr_err("\tnnode_cnt:     %d\n", c->nnode_cnt);
+	pr_err("\tdirty_pn_cnt:  %d\n", c->dirty_pn_cnt);
+	pr_err("\tdirty_nn_cnt:  %d\n", c->dirty_nn_cnt);
+	pr_err("\tlsave_cnt:     %d\n", c->lsave_cnt);
+	pr_err("\tspace_bits:    %d\n", c->space_bits);
+	pr_err("\tlpt_lnum_bits: %d\n", c->lpt_lnum_bits);
+	pr_err("\tlpt_offs_bits: %d\n", c->lpt_offs_bits);
+	pr_err("\tlpt_spc_bits:  %d\n", c->lpt_spc_bits);
+	pr_err("\tpcnt_bits:     %d\n", c->pcnt_bits);
+	pr_err("\tlnum_bits:     %d\n", c->lnum_bits);
+	pr_err("\tLPT root is at %d:%d\n", c->lpt_lnum, c->lpt_offs);
+	pr_err("\tLPT head is at %d:%d\n",
+	       c->nhead_lnum, c->nhead_offs);
+	pr_err("\tLPT ltab is at %d:%d\n", c->ltab_lnum, c->ltab_offs);
+	if (c->big_lpt)
+		pr_err("\tLPT lsave is at %d:%d\n",
+		       c->lsave_lnum, c->lsave_offs);
+	for (i = 0; i < c->lpt_lebs; i++)
+		pr_err("\tLPT LEB %d free %d dirty %d tgc %d cmt %d\n",
+		       i + c->lpt_first, c->ltab[i].free, c->ltab[i].dirty,
+		       c->ltab[i].tgc, c->ltab[i].cmt);
+	spin_unlock(&dbg_lock);
+}
+
+void ubifs_dump_leb(const struct ubifs_info *c, int lnum)
+{
+	struct ubifs_scan_leb *sleb;
+	struct ubifs_scan_node *snod;
+	void *buf;
+
+	pr_err("(pid %d) start dumping LEB %d\n", current->pid, lnum);
+
+	buf = __vmalloc(c->leb_size, GFP_NOFS);
+	if (!buf) {
+		ubifs_err(c, "cannot allocate memory for dumping LEB %d", lnum);
+		return;
+	}
+
+	sleb = ubifs_scan(c, lnum, 0, buf, 0);
+	if (IS_ERR(sleb)) {
+		ubifs_err(c, "scan error %d", (int)PTR_ERR(sleb));
+		goto out;
+	}
+
+	pr_err("LEB %d has %d nodes ending at %d\n", lnum,
+	       sleb->nodes_cnt, sleb->endpt);
+
+	list_for_each_entry(snod, &sleb->nodes, list) {
+		cond_resched();
+		pr_err("Dumping node at LEB %d:%d len %d\n", lnum,
+		       snod->offs, snod->len);
+		ubifs_dump_node(c, snod->node, c->leb_size - snod->offs);
+	}
+
+	pr_err("(pid %d) finish dumping LEB %d\n", current->pid, lnum);
+	ubifs_scan_destroy(sleb);
+
+out:
+	vfree(buf);
+	return;
+}
+
+void ubifs_dump_znode(const struct ubifs_info *c,
+		      const struct ubifs_znode *znode)
+{
+	int n;
+	const struct ubifs_zbranch *zbr;
+	char key_buf[DBG_KEY_BUF_LEN];
+
+	spin_lock(&dbg_lock);
+	if (znode->parent)
+		zbr = &znode->parent->zbranch[znode->iip];
+	else
+		zbr = &c->zroot;
+
+	pr_err("znode %p, LEB %d:%d len %d parent %p iip %d level %d child_cnt %d flags %lx\n",
+	       znode, zbr->lnum, zbr->offs, zbr->len, znode->parent, znode->iip,
+	       znode->level, znode->child_cnt, znode->flags);
+
+	if (znode->child_cnt <= 0 || znode->child_cnt > c->fanout) {
+		spin_unlock(&dbg_lock);
+		return;
+	}
+
+	pr_err("zbranches:\n");
+	for (n = 0; n < znode->child_cnt; n++) {
+		zbr = &znode->zbranch[n];
+		if (znode->level > 0)
+			pr_err("\t%d: znode %p LEB %d:%d len %d key %s\n",
+			       n, zbr->znode, zbr->lnum, zbr->offs, zbr->len,
+			       dbg_snprintf_key(c, &zbr->key, key_buf,
+						DBG_KEY_BUF_LEN));
+		else
+			pr_err("\t%d: LNC %p LEB %d:%d len %d key %s\n",
+			       n, zbr->znode, zbr->lnum, zbr->offs, zbr->len,
+			       dbg_snprintf_key(c, &zbr->key, key_buf,
+						DBG_KEY_BUF_LEN));
+	}
+	spin_unlock(&dbg_lock);
+}
+
+void ubifs_dump_heap(struct ubifs_info *c, struct ubifs_lpt_heap *heap, int cat)
+{
+	int i;
+
+	pr_err("(pid %d) start dumping heap cat %d (%d elements)\n",
+	       current->pid, cat, heap->cnt);
+	for (i = 0; i < heap->cnt; i++) {
+		struct ubifs_lprops *lprops = heap->arr[i];
+
+		pr_err("\t%d. LEB %d hpos %d free %d dirty %d flags %d\n",
+		       i, lprops->lnum, lprops->hpos, lprops->free,
+		       lprops->dirty, lprops->flags);
+	}
+	pr_err("(pid %d) finish dumping heap\n", current->pid);
+}
+
+void ubifs_dump_pnode(struct ubifs_info *c, struct ubifs_pnode *pnode,
+		      struct ubifs_nnode *parent, int iip)
+{
+	int i;
+
+	pr_err("(pid %d) dumping pnode:\n", current->pid);
+	pr_err("\taddress %zx parent %zx cnext %zx\n",
+	       (size_t)pnode, (size_t)parent, (size_t)pnode->cnext);
+	pr_err("\tflags %lu iip %d level %d num %d\n",
+	       pnode->flags, iip, pnode->level, pnode->num);
+	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+		struct ubifs_lprops *lp = &pnode->lprops[i];
+
+		pr_err("\t%d: free %d dirty %d flags %d lnum %d\n",
+		       i, lp->free, lp->dirty, lp->flags, lp->lnum);
+	}
+}
+
+void ubifs_dump_tnc(struct ubifs_info *c)
+{
+	struct ubifs_znode *znode;
+	int level;
+
+	pr_err("\n");
+	pr_err("(pid %d) start dumping TNC tree\n", current->pid);
+	znode = ubifs_tnc_levelorder_next(c, c->zroot.znode, NULL);
+	level = znode->level;
+	pr_err("== Level %d ==\n", level);
+	while (znode) {
+		if (level != znode->level) {
+			level = znode->level;
+			pr_err("== Level %d ==\n", level);
+		}
+		ubifs_dump_znode(c, znode);
+		znode = ubifs_tnc_levelorder_next(c, c->zroot.znode, znode);
+	}
+	pr_err("(pid %d) finish dumping TNC tree\n", current->pid);
+}
+
+static int dump_znode(struct ubifs_info *c, struct ubifs_znode *znode,
+		      void *priv)
+{
+	ubifs_dump_znode(c, znode);
+	return 0;
+}
+
+/**
+ * ubifs_dump_index - dump the on-flash index.
+ * @c: UBIFS file-system description object
+ *
+ * This function dumps whole UBIFS indexing B-tree, unlike 'ubifs_dump_tnc()'
+ * which dumps only in-memory znodes and does not read znodes which from flash.
+ */
+void ubifs_dump_index(struct ubifs_info *c)
+{
+	dbg_walk_index(c, NULL, dump_znode, NULL);
+}
+
+/**
+ * dbg_save_space_info - save information about flash space.
+ * @c: UBIFS file-system description object
+ *
+ * This function saves information about UBIFS free space, dirty space, etc, in
+ * order to check it later.
+ */
+void dbg_save_space_info(struct ubifs_info *c)
+{
+	struct ubifs_debug_info *d = c->dbg;
+	int freeable_cnt;
+
+	spin_lock(&c->space_lock);
+	memcpy(&d->saved_lst, &c->lst, sizeof(struct ubifs_lp_stats));
+	memcpy(&d->saved_bi, &c->bi, sizeof(struct ubifs_budg_info));
+	d->saved_idx_gc_cnt = c->idx_gc_cnt;
+
+	/*
+	 * We use a dirty hack here and zero out @c->freeable_cnt, because it
+	 * affects the free space calculations, and UBIFS might not know about
+	 * all freeable eraseblocks. Indeed, we know about freeable eraseblocks
+	 * only when we read their lprops, and we do this only lazily, upon the
+	 * need. So at any given point of time @c->freeable_cnt might be not
+	 * exactly accurate.
+	 *
+	 * Just one example about the issue we hit when we did not zero
+	 * @c->freeable_cnt.
+	 * 1. The file-system is mounted R/O, c->freeable_cnt is %0. We save the
+	 *    amount of free space in @d->saved_free
+	 * 2. We re-mount R/W, which makes UBIFS to read the "lsave"
+	 *    information from flash, where we cache LEBs from various
+	 *    categories ('ubifs_remount_fs()' -> 'ubifs_lpt_init()'
+	 *    -> 'lpt_init_wr()' -> 'read_lsave()' -> 'ubifs_lpt_lookup()'
+	 *    -> 'ubifs_get_pnode()' -> 'update_cats()'
+	 *    -> 'ubifs_add_to_cat()').
+	 * 3. Lsave contains a freeable eraseblock, and @c->freeable_cnt
+	 *    becomes %1.
+	 * 4. We calculate the amount of free space when the re-mount is
+	 *    finished in 'dbg_check_space_info()' and it does not match
+	 *    @d->saved_free.
+	 */
+	freeable_cnt = c->freeable_cnt;
+	c->freeable_cnt = 0;
+	d->saved_free = ubifs_get_free_space_nolock(c);
+	c->freeable_cnt = freeable_cnt;
+	spin_unlock(&c->space_lock);
+}
+
+/**
+ * dbg_check_space_info - check flash space information.
+ * @c: UBIFS file-system description object
+ *
+ * This function compares current flash space information with the information
+ * which was saved when the 'dbg_save_space_info()' function was called.
+ * Returns zero if the information has not changed, and %-EINVAL if it has
+ * changed.
+ */
+int dbg_check_space_info(struct ubifs_info *c)
+{
+	struct ubifs_debug_info *d = c->dbg;
+	struct ubifs_lp_stats lst;
+	long long free;
+	int freeable_cnt;
+
+	spin_lock(&c->space_lock);
+	freeable_cnt = c->freeable_cnt;
+	c->freeable_cnt = 0;
+	free = ubifs_get_free_space_nolock(c);
+	c->freeable_cnt = freeable_cnt;
+	spin_unlock(&c->space_lock);
+
+	if (free != d->saved_free) {
+		ubifs_err(c, "free space changed from %lld to %lld",
+			  d->saved_free, free);
+		goto out;
+	}
+
+	return 0;
+
+out:
+	ubifs_msg(c, "saved lprops statistics dump");
+	ubifs_dump_lstats(&d->saved_lst);
+	ubifs_msg(c, "saved budgeting info dump");
+	ubifs_dump_budg(c, &d->saved_bi);
+	ubifs_msg(c, "saved idx_gc_cnt %d", d->saved_idx_gc_cnt);
+	ubifs_msg(c, "current lprops statistics dump");
+	ubifs_get_lp_stats(c, &lst);
+	ubifs_dump_lstats(&lst);
+	ubifs_msg(c, "current budgeting info dump");
+	ubifs_dump_budg(c, &c->bi);
+	dump_stack();
+	return -EINVAL;
+}
+
+/**
+ * dbg_check_synced_i_size - check synchronized inode size.
+ * @c: UBIFS file-system description object
+ * @inode: inode to check
+ *
+ * If inode is clean, synchronized inode size has to be equivalent to current
+ * inode size. This function has to be called only for locked inodes (@i_mutex
+ * has to be locked). Returns %0 if synchronized inode size if correct, and
+ * %-EINVAL if not.
+ */
+int dbg_check_synced_i_size(const struct ubifs_info *c, struct inode *inode)
+{
+	int err = 0;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+
+	if (!dbg_is_chk_gen(c))
+		return 0;
+	if (!S_ISREG(inode->i_mode))
+		return 0;
+
+	mutex_lock(&ui->ui_mutex);
+	spin_lock(&ui->ui_lock);
+	if (ui->ui_size != ui->synced_i_size && !ui->dirty) {
+		ubifs_err(c, "ui_size is %lld, synced_i_size is %lld, but inode is clean",
+			  ui->ui_size, ui->synced_i_size);
+		ubifs_err(c, "i_ino %lu, i_mode %#x, i_size %lld", inode->i_ino,
+			  inode->i_mode, i_size_read(inode));
+		dump_stack();
+		err = -EINVAL;
+	}
+	spin_unlock(&ui->ui_lock);
+	mutex_unlock(&ui->ui_mutex);
+	return err;
+}
+
+/*
+ * dbg_check_dir - check directory inode size and link count.
+ * @c: UBIFS file-system description object
+ * @dir: the directory to calculate size for
+ * @size: the result is returned here
+ *
+ * This function makes sure that directory size and link count are correct.
+ * Returns zero in case of success and a negative error code in case of
+ * failure.
+ *
+ * Note, it is good idea to make sure the @dir->i_mutex is locked before
+ * calling this function.
+ */
+int dbg_check_dir(struct ubifs_info *c, const struct inode *dir)
+{
+	unsigned int nlink = 2;
+	union ubifs_key key;
+	struct ubifs_dent_node *dent, *pdent = NULL;
+	struct fscrypt_name nm = {0};
+	loff_t size = UBIFS_INO_NODE_SZ;
+
+	if (!dbg_is_chk_gen(c))
+		return 0;
+
+	if (!S_ISDIR(dir->i_mode))
+		return 0;
+
+	lowest_dent_key(c, &key, dir->i_ino);
+	while (1) {
+		int err;
+
+		dent = ubifs_tnc_next_ent(c, &key, &nm);
+		if (IS_ERR(dent)) {
+			err = PTR_ERR(dent);
+			if (err == -ENOENT)
+				break;
+			kfree(pdent);
+			return err;
+		}
+
+		fname_name(&nm) = dent->name;
+		fname_len(&nm) = le16_to_cpu(dent->nlen);
+		size += CALC_DENT_SIZE(fname_len(&nm));
+		if (dent->type == UBIFS_ITYPE_DIR)
+			nlink += 1;
+		kfree(pdent);
+		pdent = dent;
+		key_read(c, &dent->key, &key);
+	}
+	kfree(pdent);
+
+	if (i_size_read(dir) != size) {
+		ubifs_err(c, "directory inode %lu has size %llu, but calculated size is %llu",
+			  dir->i_ino, (unsigned long long)i_size_read(dir),
+			  (unsigned long long)size);
+		ubifs_dump_inode(c, dir);
+		dump_stack();
+		return -EINVAL;
+	}
+	if (dir->i_nlink != nlink) {
+		ubifs_err(c, "directory inode %lu has nlink %u, but calculated nlink is %u",
+			  dir->i_ino, dir->i_nlink, nlink);
+		ubifs_dump_inode(c, dir);
+		dump_stack();
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * dbg_check_key_order - make sure that colliding keys are properly ordered.
+ * @c: UBIFS file-system description object
+ * @zbr1: first zbranch
+ * @zbr2: following zbranch
+ *
+ * In UBIFS indexing B-tree colliding keys has to be sorted in binary order of
+ * names of the direntries/xentries which are referred by the keys. This
+ * function reads direntries/xentries referred by @zbr1 and @zbr2 and makes
+ * sure the name of direntry/xentry referred by @zbr1 is less than
+ * direntry/xentry referred by @zbr2. Returns zero if this is true, %1 if not,
+ * and a negative error code in case of failure.
+ */
+static int dbg_check_key_order(struct ubifs_info *c, struct ubifs_zbranch *zbr1,
+			       struct ubifs_zbranch *zbr2)
+{
+	int err, nlen1, nlen2, cmp;
+	struct ubifs_dent_node *dent1, *dent2;
+	union ubifs_key key;
+	char key_buf[DBG_KEY_BUF_LEN];
+
+	ubifs_assert(c, !keys_cmp(c, &zbr1->key, &zbr2->key));
+	dent1 = kmalloc(UBIFS_MAX_DENT_NODE_SZ, GFP_NOFS);
+	if (!dent1)
+		return -ENOMEM;
+	dent2 = kmalloc(UBIFS_MAX_DENT_NODE_SZ, GFP_NOFS);
+	if (!dent2) {
+		err = -ENOMEM;
+		goto out_free;
+	}
+
+	err = ubifs_tnc_read_node(c, zbr1, dent1);
+	if (err)
+		goto out_free;
+	err = ubifs_validate_entry(c, dent1);
+	if (err)
+		goto out_free;
+
+	err = ubifs_tnc_read_node(c, zbr2, dent2);
+	if (err)
+		goto out_free;
+	err = ubifs_validate_entry(c, dent2);
+	if (err)
+		goto out_free;
+
+	/* Make sure node keys are the same as in zbranch */
+	err = 1;
+	key_read(c, &dent1->key, &key);
+	if (keys_cmp(c, &zbr1->key, &key)) {
+		ubifs_err(c, "1st entry at %d:%d has key %s", zbr1->lnum,
+			  zbr1->offs, dbg_snprintf_key(c, &key, key_buf,
+						       DBG_KEY_BUF_LEN));
+		ubifs_err(c, "but it should have key %s according to tnc",
+			  dbg_snprintf_key(c, &zbr1->key, key_buf,
+					   DBG_KEY_BUF_LEN));
+		ubifs_dump_node(c, dent1, UBIFS_MAX_DENT_NODE_SZ);
+		goto out_free;
+	}
+
+	key_read(c, &dent2->key, &key);
+	if (keys_cmp(c, &zbr2->key, &key)) {
+		ubifs_err(c, "2nd entry at %d:%d has key %s", zbr1->lnum,
+			  zbr1->offs, dbg_snprintf_key(c, &key, key_buf,
+						       DBG_KEY_BUF_LEN));
+		ubifs_err(c, "but it should have key %s according to tnc",
+			  dbg_snprintf_key(c, &zbr2->key, key_buf,
+					   DBG_KEY_BUF_LEN));
+		ubifs_dump_node(c, dent2, UBIFS_MAX_DENT_NODE_SZ);
+		goto out_free;
+	}
+
+	nlen1 = le16_to_cpu(dent1->nlen);
+	nlen2 = le16_to_cpu(dent2->nlen);
+
+	cmp = memcmp(dent1->name, dent2->name, min_t(int, nlen1, nlen2));
+	if (cmp < 0 || (cmp == 0 && nlen1 < nlen2)) {
+		err = 0;
+		goto out_free;
+	}
+	if (cmp == 0 && nlen1 == nlen2)
+		ubifs_err(c, "2 xent/dent nodes with the same name");
+	else
+		ubifs_err(c, "bad order of colliding key %s",
+			  dbg_snprintf_key(c, &key, key_buf, DBG_KEY_BUF_LEN));
+
+	ubifs_msg(c, "first node at %d:%d\n", zbr1->lnum, zbr1->offs);
+	ubifs_dump_node(c, dent1, UBIFS_MAX_DENT_NODE_SZ);
+	ubifs_msg(c, "second node at %d:%d\n", zbr2->lnum, zbr2->offs);
+	ubifs_dump_node(c, dent2, UBIFS_MAX_DENT_NODE_SZ);
+
+out_free:
+	kfree(dent2);
+	kfree(dent1);
+	return err;
+}
+
+/**
+ * dbg_check_znode - check if znode is all right.
+ * @c: UBIFS file-system description object
+ * @zbr: zbranch which points to this znode
+ *
+ * This function makes sure that znode referred to by @zbr is all right.
+ * Returns zero if it is, and %-EINVAL if it is not.
+ */
+static int dbg_check_znode(struct ubifs_info *c, struct ubifs_zbranch *zbr)
+{
+	struct ubifs_znode *znode = zbr->znode;
+	struct ubifs_znode *zp = znode->parent;
+	int n, err, cmp;
+
+	if (znode->child_cnt <= 0 || znode->child_cnt > c->fanout) {
+		err = 1;
+		goto out;
+	}
+	if (znode->level < 0) {
+		err = 2;
+		goto out;
+	}
+	if (znode->iip < 0 || znode->iip >= c->fanout) {
+		err = 3;
+		goto out;
+	}
+
+	if (zbr->len == 0)
+		/* Only dirty zbranch may have no on-flash nodes */
+		if (!ubifs_zn_dirty(znode)) {
+			err = 4;
+			goto out;
+		}
+
+	if (ubifs_zn_dirty(znode)) {
+		/*
+		 * If znode is dirty, its parent has to be dirty as well. The
+		 * order of the operation is important, so we have to have
+		 * memory barriers.
+		 */
+		smp_mb();
+		if (zp && !ubifs_zn_dirty(zp)) {
+			/*
+			 * The dirty flag is atomic and is cleared outside the
+			 * TNC mutex, so znode's dirty flag may now have
+			 * been cleared. The child is always cleared before the
+			 * parent, so we just need to check again.
+			 */
+			smp_mb();
+			if (ubifs_zn_dirty(znode)) {
+				err = 5;
+				goto out;
+			}
+		}
+	}
+
+	if (zp) {
+		const union ubifs_key *min, *max;
+
+		if (znode->level != zp->level - 1) {
+			err = 6;
+			goto out;
+		}
+
+		/* Make sure the 'parent' pointer in our znode is correct */
+		err = ubifs_search_zbranch(c, zp, &zbr->key, &n);
+		if (!err) {
+			/* This zbranch does not exist in the parent */
+			err = 7;
+			goto out;
+		}
+
+		if (znode->iip >= zp->child_cnt) {
+			err = 8;
+			goto out;
+		}
+
+		if (znode->iip != n) {
+			/* This may happen only in case of collisions */
+			if (keys_cmp(c, &zp->zbranch[n].key,
+				     &zp->zbranch[znode->iip].key)) {
+				err = 9;
+				goto out;
+			}
+			n = znode->iip;
+		}
+
+		/*
+		 * Make sure that the first key in our znode is greater than or
+		 * equal to the key in the pointing zbranch.
+		 */
+		min = &zbr->key;
+		cmp = keys_cmp(c, min, &znode->zbranch[0].key);
+		if (cmp == 1) {
+			err = 10;
+			goto out;
+		}
+
+		if (n + 1 < zp->child_cnt) {
+			max = &zp->zbranch[n + 1].key;
+
+			/*
+			 * Make sure the last key in our znode is less or
+			 * equivalent than the key in the zbranch which goes
+			 * after our pointing zbranch.
+			 */
+			cmp = keys_cmp(c, max,
+				&znode->zbranch[znode->child_cnt - 1].key);
+			if (cmp == -1) {
+				err = 11;
+				goto out;
+			}
+		}
+	} else {
+		/* This may only be root znode */
+		if (zbr != &c->zroot) {
+			err = 12;
+			goto out;
+		}
+	}
+
+	/*
+	 * Make sure that next key is greater or equivalent then the previous
+	 * one.
+	 */
+	for (n = 1; n < znode->child_cnt; n++) {
+		cmp = keys_cmp(c, &znode->zbranch[n - 1].key,
+			       &znode->zbranch[n].key);
+		if (cmp > 0) {
+			err = 13;
+			goto out;
+		}
+		if (cmp == 0) {
+			/* This can only be keys with colliding hash */
+			if (!is_hash_key(c, &znode->zbranch[n].key)) {
+				err = 14;
+				goto out;
+			}
+
+			if (znode->level != 0 || c->replaying)
+				continue;
+
+			/*
+			 * Colliding keys should follow binary order of
+			 * corresponding xentry/dentry names.
+			 */
+			err = dbg_check_key_order(c, &znode->zbranch[n - 1],
+						  &znode->zbranch[n]);
+			if (err < 0)
+				return err;
+			if (err) {
+				err = 15;
+				goto out;
+			}
+		}
+	}
+
+	for (n = 0; n < znode->child_cnt; n++) {
+		if (!znode->zbranch[n].znode &&
+		    (znode->zbranch[n].lnum == 0 ||
+		     znode->zbranch[n].len == 0)) {
+			err = 16;
+			goto out;
+		}
+
+		if (znode->zbranch[n].lnum != 0 &&
+		    znode->zbranch[n].len == 0) {
+			err = 17;
+			goto out;
+		}
+
+		if (znode->zbranch[n].lnum == 0 &&
+		    znode->zbranch[n].len != 0) {
+			err = 18;
+			goto out;
+		}
+
+		if (znode->zbranch[n].lnum == 0 &&
+		    znode->zbranch[n].offs != 0) {
+			err = 19;
+			goto out;
+		}
+
+		if (znode->level != 0 && znode->zbranch[n].znode)
+			if (znode->zbranch[n].znode->parent != znode) {
+				err = 20;
+				goto out;
+			}
+	}
+
+	return 0;
+
+out:
+	ubifs_err(c, "failed, error %d", err);
+	ubifs_msg(c, "dump of the znode");
+	ubifs_dump_znode(c, znode);
+	if (zp) {
+		ubifs_msg(c, "dump of the parent znode");
+		ubifs_dump_znode(c, zp);
+	}
+	dump_stack();
+	return -EINVAL;
+}
+
+/**
+ * dbg_check_tnc - check TNC tree.
+ * @c: UBIFS file-system description object
+ * @extra: do extra checks that are possible at start commit
+ *
+ * This function traverses whole TNC tree and checks every znode. Returns zero
+ * if everything is all right and %-EINVAL if something is wrong with TNC.
+ */
+int dbg_check_tnc(struct ubifs_info *c, int extra)
+{
+	struct ubifs_znode *znode;
+	long clean_cnt = 0, dirty_cnt = 0;
+	int err, last;
+
+	if (!dbg_is_chk_index(c))
+		return 0;
+
+	ubifs_assert(c, mutex_is_locked(&c->tnc_mutex));
+	if (!c->zroot.znode)
+		return 0;
+
+	znode = ubifs_tnc_postorder_first(c->zroot.znode);
+	while (1) {
+		struct ubifs_znode *prev;
+		struct ubifs_zbranch *zbr;
+
+		if (!znode->parent)
+			zbr = &c->zroot;
+		else
+			zbr = &znode->parent->zbranch[znode->iip];
+
+		err = dbg_check_znode(c, zbr);
+		if (err)
+			return err;
+
+		if (extra) {
+			if (ubifs_zn_dirty(znode))
+				dirty_cnt += 1;
+			else
+				clean_cnt += 1;
+		}
+
+		prev = znode;
+		znode = ubifs_tnc_postorder_next(c, znode);
+		if (!znode)
+			break;
+
+		/*
+		 * If the last key of this znode is equivalent to the first key
+		 * of the next znode (collision), then check order of the keys.
+		 */
+		last = prev->child_cnt - 1;
+		if (prev->level == 0 && znode->level == 0 && !c->replaying &&
+		    !keys_cmp(c, &prev->zbranch[last].key,
+			      &znode->zbranch[0].key)) {
+			err = dbg_check_key_order(c, &prev->zbranch[last],
+						  &znode->zbranch[0]);
+			if (err < 0)
+				return err;
+			if (err) {
+				ubifs_msg(c, "first znode");
+				ubifs_dump_znode(c, prev);
+				ubifs_msg(c, "second znode");
+				ubifs_dump_znode(c, znode);
+				return -EINVAL;
+			}
+		}
+	}
+
+	if (extra) {
+		if (clean_cnt != atomic_long_read(&c->clean_zn_cnt)) {
+			ubifs_err(c, "incorrect clean_zn_cnt %ld, calculated %ld",
+				  atomic_long_read(&c->clean_zn_cnt),
+				  clean_cnt);
+			return -EINVAL;
+		}
+		if (dirty_cnt != atomic_long_read(&c->dirty_zn_cnt)) {
+			ubifs_err(c, "incorrect dirty_zn_cnt %ld, calculated %ld",
+				  atomic_long_read(&c->dirty_zn_cnt),
+				  dirty_cnt);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * dbg_walk_index - walk the on-flash index.
+ * @c: UBIFS file-system description object
+ * @leaf_cb: called for each leaf node
+ * @znode_cb: called for each indexing node
+ * @priv: private data which is passed to callbacks
+ *
+ * This function walks the UBIFS index and calls the @leaf_cb for each leaf
+ * node and @znode_cb for each indexing node. Returns zero in case of success
+ * and a negative error code in case of failure.
+ *
+ * It would be better if this function removed every znode it pulled to into
+ * the TNC, so that the behavior more closely matched the non-debugging
+ * behavior.
+ */
+int dbg_walk_index(struct ubifs_info *c, dbg_leaf_callback leaf_cb,
+		   dbg_znode_callback znode_cb, void *priv)
+{
+	int err;
+	struct ubifs_zbranch *zbr;
+	struct ubifs_znode *znode, *child;
+
+	mutex_lock(&c->tnc_mutex);
+	/* If the root indexing node is not in TNC - pull it */
+	if (!c->zroot.znode) {
+		c->zroot.znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
+		if (IS_ERR(c->zroot.znode)) {
+			err = PTR_ERR(c->zroot.znode);
+			c->zroot.znode = NULL;
+			goto out_unlock;
+		}
+	}
+
+	/*
+	 * We are going to traverse the indexing tree in the postorder manner.
+	 * Go down and find the leftmost indexing node where we are going to
+	 * start from.
+	 */
+	znode = c->zroot.znode;
+	while (znode->level > 0) {
+		zbr = &znode->zbranch[0];
+		child = zbr->znode;
+		if (!child) {
+			child = ubifs_load_znode(c, zbr, znode, 0);
+			if (IS_ERR(child)) {
+				err = PTR_ERR(child);
+				goto out_unlock;
+			}
+		}
+
+		znode = child;
+	}
+
+	/* Iterate over all indexing nodes */
+	while (1) {
+		int idx;
+
+		cond_resched();
+
+		if (znode_cb) {
+			err = znode_cb(c, znode, priv);
+			if (err) {
+				ubifs_err(c, "znode checking function returned error %d",
+					  err);
+				ubifs_dump_znode(c, znode);
+				goto out_dump;
+			}
+		}
+		if (leaf_cb && znode->level == 0) {
+			for (idx = 0; idx < znode->child_cnt; idx++) {
+				zbr = &znode->zbranch[idx];
+				err = leaf_cb(c, zbr, priv);
+				if (err) {
+					ubifs_err(c, "leaf checking function returned error %d, for leaf at LEB %d:%d",
+						  err, zbr->lnum, zbr->offs);
+					goto out_dump;
+				}
+			}
+		}
+
+		if (!znode->parent)
+			break;
+
+		idx = znode->iip + 1;
+		znode = znode->parent;
+		if (idx < znode->child_cnt) {
+			/* Switch to the next index in the parent */
+			zbr = &znode->zbranch[idx];
+			child = zbr->znode;
+			if (!child) {
+				child = ubifs_load_znode(c, zbr, znode, idx);
+				if (IS_ERR(child)) {
+					err = PTR_ERR(child);
+					goto out_unlock;
+				}
+				zbr->znode = child;
+			}
+			znode = child;
+		} else
+			/*
+			 * This is the last child, switch to the parent and
+			 * continue.
+			 */
+			continue;
+
+		/* Go to the lowest leftmost znode in the new sub-tree */
+		while (znode->level > 0) {
+			zbr = &znode->zbranch[0];
+			child = zbr->znode;
+			if (!child) {
+				child = ubifs_load_znode(c, zbr, znode, 0);
+				if (IS_ERR(child)) {
+					err = PTR_ERR(child);
+					goto out_unlock;
+				}
+				zbr->znode = child;
+			}
+			znode = child;
+		}
+	}
+
+	mutex_unlock(&c->tnc_mutex);
+	return 0;
+
+out_dump:
+	if (znode->parent)
+		zbr = &znode->parent->zbranch[znode->iip];
+	else
+		zbr = &c->zroot;
+	ubifs_msg(c, "dump of znode at LEB %d:%d", zbr->lnum, zbr->offs);
+	ubifs_dump_znode(c, znode);
+out_unlock:
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * add_size - add znode size to partially calculated index size.
+ * @c: UBIFS file-system description object
+ * @znode: znode to add size for
+ * @priv: partially calculated index size
+ *
+ * This is a helper function for 'dbg_check_idx_size()' which is called for
+ * every indexing node and adds its size to the 'long long' variable pointed to
+ * by @priv.
+ */
+static int add_size(struct ubifs_info *c, struct ubifs_znode *znode, void *priv)
+{
+	long long *idx_size = priv;
+	int add;
+
+	add = ubifs_idx_node_sz(c, znode->child_cnt);
+	add = ALIGN(add, 8);
+	*idx_size += add;
+	return 0;
+}
+
+/**
+ * dbg_check_idx_size - check index size.
+ * @c: UBIFS file-system description object
+ * @idx_size: size to check
+ *
+ * This function walks the UBIFS index, calculates its size and checks that the
+ * size is equivalent to @idx_size. Returns zero in case of success and a
+ * negative error code in case of failure.
+ */
+int dbg_check_idx_size(struct ubifs_info *c, long long idx_size)
+{
+	int err;
+	long long calc = 0;
+
+	if (!dbg_is_chk_index(c))
+		return 0;
+
+	err = dbg_walk_index(c, NULL, add_size, &calc);
+	if (err) {
+		ubifs_err(c, "error %d while walking the index", err);
+		goto out_err;
+	}
+
+	if (calc != idx_size) {
+		ubifs_err(c, "index size check failed: calculated size is %lld, should be %lld",
+			  calc, idx_size);
+		dump_stack();
+		err = -EINVAL;
+		goto out_err;
+	}
+
+	return 0;
+
+out_err:
+	ubifs_destroy_tnc_tree(c);
+	return err;
+}
+
+/**
+ * struct fsck_inode - information about an inode used when checking the file-system.
+ * @rb: link in the RB-tree of inodes
+ * @inum: inode number
+ * @mode: inode type, permissions, etc
+ * @nlink: inode link count
+ * @xattr_cnt: count of extended attributes
+ * @references: how many directory/xattr entries refer this inode (calculated
+ *              while walking the index)
+ * @calc_cnt: for directory inode count of child directories
+ * @size: inode size (read from on-flash inode)
+ * @xattr_sz: summary size of all extended attributes (read from on-flash
+ *            inode)
+ * @calc_sz: for directories calculated directory size
+ * @calc_xcnt: count of extended attributes
+ * @calc_xsz: calculated summary size of all extended attributes
+ * @xattr_nms: sum of lengths of all extended attribute names belonging to this
+ *             inode (read from on-flash inode)
+ * @calc_xnms: calculated sum of lengths of all extended attribute names
+ */
+struct fsck_inode {
+	struct rb_node rb;
+	ino_t inum;
+	umode_t mode;
+	unsigned int nlink;
+	unsigned int xattr_cnt;
+	int references;
+	int calc_cnt;
+	long long size;
+	unsigned int xattr_sz;
+	long long calc_sz;
+	long long calc_xcnt;
+	long long calc_xsz;
+	unsigned int xattr_nms;
+	long long calc_xnms;
+};
+
+/**
+ * struct fsck_data - private FS checking information.
+ * @inodes: RB-tree of all inodes (contains @struct fsck_inode objects)
+ */
+struct fsck_data {
+	struct rb_root inodes;
+};
+
+/**
+ * add_inode - add inode information to RB-tree of inodes.
+ * @c: UBIFS file-system description object
+ * @fsckd: FS checking information
+ * @ino: raw UBIFS inode to add
+ *
+ * This is a helper function for 'check_leaf()' which adds information about
+ * inode @ino to the RB-tree of inodes. Returns inode information pointer in
+ * case of success and a negative error code in case of failure.
+ */
+static struct fsck_inode *add_inode(struct ubifs_info *c,
+				    struct fsck_data *fsckd,
+				    struct ubifs_ino_node *ino)
+{
+	struct rb_node **p, *parent = NULL;
+	struct fsck_inode *fscki;
+	ino_t inum = key_inum_flash(c, &ino->key);
+	struct inode *inode;
+	struct ubifs_inode *ui;
+
+	p = &fsckd->inodes.rb_node;
+	while (*p) {
+		parent = *p;
+		fscki = rb_entry(parent, struct fsck_inode, rb);
+		if (inum < fscki->inum)
+			p = &(*p)->rb_left;
+		else if (inum > fscki->inum)
+			p = &(*p)->rb_right;
+		else
+			return fscki;
+	}
+
+	if (inum > c->highest_inum) {
+		ubifs_err(c, "too high inode number, max. is %lu",
+			  (unsigned long)c->highest_inum);
+		return ERR_PTR(-EINVAL);
+	}
+
+	fscki = kzalloc(sizeof(struct fsck_inode), GFP_NOFS);
+	if (!fscki)
+		return ERR_PTR(-ENOMEM);
+
+	inode = ilookup(c->vfs_sb, inum);
+
+	fscki->inum = inum;
+	/*
+	 * If the inode is present in the VFS inode cache, use it instead of
+	 * the on-flash inode which might be out-of-date. E.g., the size might
+	 * be out-of-date. If we do not do this, the following may happen, for
+	 * example:
+	 *   1. A power cut happens
+	 *   2. We mount the file-system R/O, the replay process fixes up the
+	 *      inode size in the VFS cache, but on on-flash.
+	 *   3. 'check_leaf()' fails because it hits a data node beyond inode
+	 *      size.
+	 */
+	if (!inode) {
+		fscki->nlink = le32_to_cpu(ino->nlink);
+		fscki->size = le64_to_cpu(ino->size);
+		fscki->xattr_cnt = le32_to_cpu(ino->xattr_cnt);
+		fscki->xattr_sz = le32_to_cpu(ino->xattr_size);
+		fscki->xattr_nms = le32_to_cpu(ino->xattr_names);
+		fscki->mode = le32_to_cpu(ino->mode);
+	} else {
+		ui = ubifs_inode(inode);
+		fscki->nlink = inode->i_nlink;
+		fscki->size = inode->i_size;
+		fscki->xattr_cnt = ui->xattr_cnt;
+		fscki->xattr_sz = ui->xattr_size;
+		fscki->xattr_nms = ui->xattr_names;
+		fscki->mode = inode->i_mode;
+		iput(inode);
+	}
+
+	if (S_ISDIR(fscki->mode)) {
+		fscki->calc_sz = UBIFS_INO_NODE_SZ;
+		fscki->calc_cnt = 2;
+	}
+
+	rb_link_node(&fscki->rb, parent, p);
+	rb_insert_color(&fscki->rb, &fsckd->inodes);
+
+	return fscki;
+}
+
+/**
+ * search_inode - search inode in the RB-tree of inodes.
+ * @fsckd: FS checking information
+ * @inum: inode number to search
+ *
+ * This is a helper function for 'check_leaf()' which searches inode @inum in
+ * the RB-tree of inodes and returns an inode information pointer or %NULL if
+ * the inode was not found.
+ */
+static struct fsck_inode *search_inode(struct fsck_data *fsckd, ino_t inum)
+{
+	struct rb_node *p;
+	struct fsck_inode *fscki;
+
+	p = fsckd->inodes.rb_node;
+	while (p) {
+		fscki = rb_entry(p, struct fsck_inode, rb);
+		if (inum < fscki->inum)
+			p = p->rb_left;
+		else if (inum > fscki->inum)
+			p = p->rb_right;
+		else
+			return fscki;
+	}
+	return NULL;
+}
+
+/**
+ * read_add_inode - read inode node and add it to RB-tree of inodes.
+ * @c: UBIFS file-system description object
+ * @fsckd: FS checking information
+ * @inum: inode number to read
+ *
+ * This is a helper function for 'check_leaf()' which finds inode node @inum in
+ * the index, reads it, and adds it to the RB-tree of inodes. Returns inode
+ * information pointer in case of success and a negative error code in case of
+ * failure.
+ */
+static struct fsck_inode *read_add_inode(struct ubifs_info *c,
+					 struct fsck_data *fsckd, ino_t inum)
+{
+	int n, err;
+	union ubifs_key key;
+	struct ubifs_znode *znode;
+	struct ubifs_zbranch *zbr;
+	struct ubifs_ino_node *ino;
+	struct fsck_inode *fscki;
+
+	fscki = search_inode(fsckd, inum);
+	if (fscki)
+		return fscki;
+
+	ino_key_init(c, &key, inum);
+	err = ubifs_lookup_level0(c, &key, &znode, &n);
+	if (!err) {
+		ubifs_err(c, "inode %lu not found in index", (unsigned long)inum);
+		return ERR_PTR(-ENOENT);
+	} else if (err < 0) {
+		ubifs_err(c, "error %d while looking up inode %lu",
+			  err, (unsigned long)inum);
+		return ERR_PTR(err);
+	}
+
+	zbr = &znode->zbranch[n];
+	if (zbr->len < UBIFS_INO_NODE_SZ) {
+		ubifs_err(c, "bad node %lu node length %d",
+			  (unsigned long)inum, zbr->len);
+		return ERR_PTR(-EINVAL);
+	}
+
+	ino = kmalloc(zbr->len, GFP_NOFS);
+	if (!ino)
+		return ERR_PTR(-ENOMEM);
+
+	err = ubifs_tnc_read_node(c, zbr, ino);
+	if (err) {
+		ubifs_err(c, "cannot read inode node at LEB %d:%d, error %d",
+			  zbr->lnum, zbr->offs, err);
+		kfree(ino);
+		return ERR_PTR(err);
+	}
+
+	fscki = add_inode(c, fsckd, ino);
+	kfree(ino);
+	if (IS_ERR(fscki)) {
+		ubifs_err(c, "error %ld while adding inode %lu node",
+			  PTR_ERR(fscki), (unsigned long)inum);
+		return fscki;
+	}
+
+	return fscki;
+}
+
+/**
+ * check_leaf - check leaf node.
+ * @c: UBIFS file-system description object
+ * @zbr: zbranch of the leaf node to check
+ * @priv: FS checking information
+ *
+ * This is a helper function for 'dbg_check_filesystem()' which is called for
+ * every single leaf node while walking the indexing tree. It checks that the
+ * leaf node referred from the indexing tree exists, has correct CRC, and does
+ * some other basic validation. This function is also responsible for building
+ * an RB-tree of inodes - it adds all inodes into the RB-tree. It also
+ * calculates reference count, size, etc for each inode in order to later
+ * compare them to the information stored inside the inodes and detect possible
+ * inconsistencies. Returns zero in case of success and a negative error code
+ * in case of failure.
+ */
+static int check_leaf(struct ubifs_info *c, struct ubifs_zbranch *zbr,
+		      void *priv)
+{
+	ino_t inum;
+	void *node;
+	struct ubifs_ch *ch;
+	int err, type = key_type(c, &zbr->key);
+	struct fsck_inode *fscki;
+
+	if (zbr->len < UBIFS_CH_SZ) {
+		ubifs_err(c, "bad leaf length %d (LEB %d:%d)",
+			  zbr->len, zbr->lnum, zbr->offs);
+		return -EINVAL;
+	}
+
+	node = kmalloc(zbr->len, GFP_NOFS);
+	if (!node)
+		return -ENOMEM;
+
+	err = ubifs_tnc_read_node(c, zbr, node);
+	if (err) {
+		ubifs_err(c, "cannot read leaf node at LEB %d:%d, error %d",
+			  zbr->lnum, zbr->offs, err);
+		goto out_free;
+	}
+
+	/* If this is an inode node, add it to RB-tree of inodes */
+	if (type == UBIFS_INO_KEY) {
+		fscki = add_inode(c, priv, node);
+		if (IS_ERR(fscki)) {
+			err = PTR_ERR(fscki);
+			ubifs_err(c, "error %d while adding inode node", err);
+			goto out_dump;
+		}
+		goto out;
+	}
+
+	if (type != UBIFS_DENT_KEY && type != UBIFS_XENT_KEY &&
+	    type != UBIFS_DATA_KEY) {
+		ubifs_err(c, "unexpected node type %d at LEB %d:%d",
+			  type, zbr->lnum, zbr->offs);
+		err = -EINVAL;
+		goto out_free;
+	}
+
+	ch = node;
+	if (le64_to_cpu(ch->sqnum) > c->max_sqnum) {
+		ubifs_err(c, "too high sequence number, max. is %llu",
+			  c->max_sqnum);
+		err = -EINVAL;
+		goto out_dump;
+	}
+
+	if (type == UBIFS_DATA_KEY) {
+		long long blk_offs;
+		struct ubifs_data_node *dn = node;
+
+		ubifs_assert(c, zbr->len >= UBIFS_DATA_NODE_SZ);
+
+		/*
+		 * Search the inode node this data node belongs to and insert
+		 * it to the RB-tree of inodes.
+		 */
+		inum = key_inum_flash(c, &dn->key);
+		fscki = read_add_inode(c, priv, inum);
+		if (IS_ERR(fscki)) {
+			err = PTR_ERR(fscki);
+			ubifs_err(c, "error %d while processing data node and trying to find inode node %lu",
+				  err, (unsigned long)inum);
+			goto out_dump;
+		}
+
+		/* Make sure the data node is within inode size */
+		blk_offs = key_block_flash(c, &dn->key);
+		blk_offs <<= UBIFS_BLOCK_SHIFT;
+		blk_offs += le32_to_cpu(dn->size);
+		if (blk_offs > fscki->size) {
+			ubifs_err(c, "data node at LEB %d:%d is not within inode size %lld",
+				  zbr->lnum, zbr->offs, fscki->size);
+			err = -EINVAL;
+			goto out_dump;
+		}
+	} else {
+		int nlen;
+		struct ubifs_dent_node *dent = node;
+		struct fsck_inode *fscki1;
+
+		ubifs_assert(c, zbr->len >= UBIFS_DENT_NODE_SZ);
+
+		err = ubifs_validate_entry(c, dent);
+		if (err)
+			goto out_dump;
+
+		/*
+		 * Search the inode node this entry refers to and the parent
+		 * inode node and insert them to the RB-tree of inodes.
+		 */
+		inum = le64_to_cpu(dent->inum);
+		fscki = read_add_inode(c, priv, inum);
+		if (IS_ERR(fscki)) {
+			err = PTR_ERR(fscki);
+			ubifs_err(c, "error %d while processing entry node and trying to find inode node %lu",
+				  err, (unsigned long)inum);
+			goto out_dump;
+		}
+
+		/* Count how many direntries or xentries refers this inode */
+		fscki->references += 1;
+
+		inum = key_inum_flash(c, &dent->key);
+		fscki1 = read_add_inode(c, priv, inum);
+		if (IS_ERR(fscki1)) {
+			err = PTR_ERR(fscki1);
+			ubifs_err(c, "error %d while processing entry node and trying to find parent inode node %lu",
+				  err, (unsigned long)inum);
+			goto out_dump;
+		}
+
+		nlen = le16_to_cpu(dent->nlen);
+		if (type == UBIFS_XENT_KEY) {
+			fscki1->calc_xcnt += 1;
+			fscki1->calc_xsz += CALC_DENT_SIZE(nlen);
+			fscki1->calc_xsz += CALC_XATTR_BYTES(fscki->size);
+			fscki1->calc_xnms += nlen;
+		} else {
+			fscki1->calc_sz += CALC_DENT_SIZE(nlen);
+			if (dent->type == UBIFS_ITYPE_DIR)
+				fscki1->calc_cnt += 1;
+		}
+	}
+
+out:
+	kfree(node);
+	return 0;
+
+out_dump:
+	ubifs_msg(c, "dump of node at LEB %d:%d", zbr->lnum, zbr->offs);
+	ubifs_dump_node(c, node, zbr->len);
+out_free:
+	kfree(node);
+	return err;
+}
+
+/**
+ * free_inodes - free RB-tree of inodes.
+ * @fsckd: FS checking information
+ */
+static void free_inodes(struct fsck_data *fsckd)
+{
+	struct fsck_inode *fscki, *n;
+
+	rbtree_postorder_for_each_entry_safe(fscki, n, &fsckd->inodes, rb)
+		kfree(fscki);
+}
+
+/**
+ * check_inodes - checks all inodes.
+ * @c: UBIFS file-system description object
+ * @fsckd: FS checking information
+ *
+ * This is a helper function for 'dbg_check_filesystem()' which walks the
+ * RB-tree of inodes after the index scan has been finished, and checks that
+ * inode nlink, size, etc are correct. Returns zero if inodes are fine,
+ * %-EINVAL if not, and a negative error code in case of failure.
+ */
+static int check_inodes(struct ubifs_info *c, struct fsck_data *fsckd)
+{
+	int n, err;
+	union ubifs_key key;
+	struct ubifs_znode *znode;
+	struct ubifs_zbranch *zbr;
+	struct ubifs_ino_node *ino;
+	struct fsck_inode *fscki;
+	struct rb_node *this = rb_first(&fsckd->inodes);
+
+	while (this) {
+		fscki = rb_entry(this, struct fsck_inode, rb);
+		this = rb_next(this);
+
+		if (S_ISDIR(fscki->mode)) {
+			/*
+			 * Directories have to have exactly one reference (they
+			 * cannot have hardlinks), although root inode is an
+			 * exception.
+			 */
+			if (fscki->inum != UBIFS_ROOT_INO &&
+			    fscki->references != 1) {
+				ubifs_err(c, "directory inode %lu has %d direntries which refer it, but should be 1",
+					  (unsigned long)fscki->inum,
+					  fscki->references);
+				goto out_dump;
+			}
+			if (fscki->inum == UBIFS_ROOT_INO &&
+			    fscki->references != 0) {
+				ubifs_err(c, "root inode %lu has non-zero (%d) direntries which refer it",
+					  (unsigned long)fscki->inum,
+					  fscki->references);
+				goto out_dump;
+			}
+			if (fscki->calc_sz != fscki->size) {
+				ubifs_err(c, "directory inode %lu size is %lld, but calculated size is %lld",
+					  (unsigned long)fscki->inum,
+					  fscki->size, fscki->calc_sz);
+				goto out_dump;
+			}
+			if (fscki->calc_cnt != fscki->nlink) {
+				ubifs_err(c, "directory inode %lu nlink is %d, but calculated nlink is %d",
+					  (unsigned long)fscki->inum,
+					  fscki->nlink, fscki->calc_cnt);
+				goto out_dump;
+			}
+		} else {
+			if (fscki->references != fscki->nlink) {
+				ubifs_err(c, "inode %lu nlink is %d, but calculated nlink is %d",
+					  (unsigned long)fscki->inum,
+					  fscki->nlink, fscki->references);
+				goto out_dump;
+			}
+		}
+		if (fscki->xattr_sz != fscki->calc_xsz) {
+			ubifs_err(c, "inode %lu has xattr size %u, but calculated size is %lld",
+				  (unsigned long)fscki->inum, fscki->xattr_sz,
+				  fscki->calc_xsz);
+			goto out_dump;
+		}
+		if (fscki->xattr_cnt != fscki->calc_xcnt) {
+			ubifs_err(c, "inode %lu has %u xattrs, but calculated count is %lld",
+				  (unsigned long)fscki->inum,
+				  fscki->xattr_cnt, fscki->calc_xcnt);
+			goto out_dump;
+		}
+		if (fscki->xattr_nms != fscki->calc_xnms) {
+			ubifs_err(c, "inode %lu has xattr names' size %u, but calculated names' size is %lld",
+				  (unsigned long)fscki->inum, fscki->xattr_nms,
+				  fscki->calc_xnms);
+			goto out_dump;
+		}
+	}
+
+	return 0;
+
+out_dump:
+	/* Read the bad inode and dump it */
+	ino_key_init(c, &key, fscki->inum);
+	err = ubifs_lookup_level0(c, &key, &znode, &n);
+	if (!err) {
+		ubifs_err(c, "inode %lu not found in index",
+			  (unsigned long)fscki->inum);
+		return -ENOENT;
+	} else if (err < 0) {
+		ubifs_err(c, "error %d while looking up inode %lu",
+			  err, (unsigned long)fscki->inum);
+		return err;
+	}
+
+	zbr = &znode->zbranch[n];
+	ino = kmalloc(zbr->len, GFP_NOFS);
+	if (!ino)
+		return -ENOMEM;
+
+	err = ubifs_tnc_read_node(c, zbr, ino);
+	if (err) {
+		ubifs_err(c, "cannot read inode node at LEB %d:%d, error %d",
+			  zbr->lnum, zbr->offs, err);
+		kfree(ino);
+		return err;
+	}
+
+	ubifs_msg(c, "dump of the inode %lu sitting in LEB %d:%d",
+		  (unsigned long)fscki->inum, zbr->lnum, zbr->offs);
+	ubifs_dump_node(c, ino, zbr->len);
+	kfree(ino);
+	return -EINVAL;
+}
+
+/**
+ * dbg_check_filesystem - check the file-system.
+ * @c: UBIFS file-system description object
+ *
+ * This function checks the file system, namely:
+ * o makes sure that all leaf nodes exist and their CRCs are correct;
+ * o makes sure inode nlink, size, xattr size/count are correct (for all
+ *   inodes).
+ *
+ * The function reads whole indexing tree and all nodes, so it is pretty
+ * heavy-weight. Returns zero if the file-system is consistent, %-EINVAL if
+ * not, and a negative error code in case of failure.
+ */
+int dbg_check_filesystem(struct ubifs_info *c)
+{
+	int err;
+	struct fsck_data fsckd;
+
+	if (!dbg_is_chk_fs(c))
+		return 0;
+
+	fsckd.inodes = RB_ROOT;
+	err = dbg_walk_index(c, check_leaf, NULL, &fsckd);
+	if (err)
+		goto out_free;
+
+	err = check_inodes(c, &fsckd);
+	if (err)
+		goto out_free;
+
+	free_inodes(&fsckd);
+	return 0;
+
+out_free:
+	ubifs_err(c, "file-system check failed with error %d", err);
+	dump_stack();
+	free_inodes(&fsckd);
+	return err;
+}
+
+/**
+ * dbg_check_data_nodes_order - check that list of data nodes is sorted.
+ * @c: UBIFS file-system description object
+ * @head: the list of nodes ('struct ubifs_scan_node' objects)
+ *
+ * This function returns zero if the list of data nodes is sorted correctly,
+ * and %-EINVAL if not.
+ */
+int dbg_check_data_nodes_order(struct ubifs_info *c, struct list_head *head)
+{
+	struct list_head *cur;
+	struct ubifs_scan_node *sa, *sb;
+
+	if (!dbg_is_chk_gen(c))
+		return 0;
+
+	for (cur = head->next; cur->next != head; cur = cur->next) {
+		ino_t inuma, inumb;
+		uint32_t blka, blkb;
+
+		cond_resched();
+		sa = container_of(cur, struct ubifs_scan_node, list);
+		sb = container_of(cur->next, struct ubifs_scan_node, list);
+
+		if (sa->type != UBIFS_DATA_NODE) {
+			ubifs_err(c, "bad node type %d", sa->type);
+			ubifs_dump_node(c, sa->node, c->leb_size - sa->offs);
+			return -EINVAL;
+		}
+		if (sb->type != UBIFS_DATA_NODE) {
+			ubifs_err(c, "bad node type %d", sb->type);
+			ubifs_dump_node(c, sb->node, c->leb_size - sb->offs);
+			return -EINVAL;
+		}
+
+		inuma = key_inum(c, &sa->key);
+		inumb = key_inum(c, &sb->key);
+
+		if (inuma < inumb)
+			continue;
+		if (inuma > inumb) {
+			ubifs_err(c, "larger inum %lu goes before inum %lu",
+				  (unsigned long)inuma, (unsigned long)inumb);
+			goto error_dump;
+		}
+
+		blka = key_block(c, &sa->key);
+		blkb = key_block(c, &sb->key);
+
+		if (blka > blkb) {
+			ubifs_err(c, "larger block %u goes before %u", blka, blkb);
+			goto error_dump;
+		}
+		if (blka == blkb) {
+			ubifs_err(c, "two data nodes for the same block");
+			goto error_dump;
+		}
+	}
+
+	return 0;
+
+error_dump:
+	ubifs_dump_node(c, sa->node, c->leb_size - sa->offs);
+	ubifs_dump_node(c, sb->node, c->leb_size - sb->offs);
+	return -EINVAL;
+}
+
+/**
+ * dbg_check_nondata_nodes_order - check that list of data nodes is sorted.
+ * @c: UBIFS file-system description object
+ * @head: the list of nodes ('struct ubifs_scan_node' objects)
+ *
+ * This function returns zero if the list of non-data nodes is sorted correctly,
+ * and %-EINVAL if not.
+ */
+int dbg_check_nondata_nodes_order(struct ubifs_info *c, struct list_head *head)
+{
+	struct list_head *cur;
+	struct ubifs_scan_node *sa, *sb;
+
+	if (!dbg_is_chk_gen(c))
+		return 0;
+
+	for (cur = head->next; cur->next != head; cur = cur->next) {
+		ino_t inuma, inumb;
+		uint32_t hasha, hashb;
+
+		cond_resched();
+		sa = container_of(cur, struct ubifs_scan_node, list);
+		sb = container_of(cur->next, struct ubifs_scan_node, list);
+
+		if (sa->type != UBIFS_INO_NODE && sa->type != UBIFS_DENT_NODE &&
+		    sa->type != UBIFS_XENT_NODE) {
+			ubifs_err(c, "bad node type %d", sa->type);
+			ubifs_dump_node(c, sa->node, c->leb_size - sa->offs);
+			return -EINVAL;
+		}
+		if (sb->type != UBIFS_INO_NODE && sb->type != UBIFS_DENT_NODE &&
+		    sb->type != UBIFS_XENT_NODE) {
+			ubifs_err(c, "bad node type %d", sb->type);
+			ubifs_dump_node(c, sb->node, c->leb_size - sb->offs);
+			return -EINVAL;
+		}
+
+		if (sa->type != UBIFS_INO_NODE && sb->type == UBIFS_INO_NODE) {
+			ubifs_err(c, "non-inode node goes before inode node");
+			goto error_dump;
+		}
+
+		if (sa->type == UBIFS_INO_NODE && sb->type != UBIFS_INO_NODE)
+			continue;
+
+		if (sa->type == UBIFS_INO_NODE && sb->type == UBIFS_INO_NODE) {
+			/* Inode nodes are sorted in descending size order */
+			if (sa->len < sb->len) {
+				ubifs_err(c, "smaller inode node goes first");
+				goto error_dump;
+			}
+			continue;
+		}
+
+		/*
+		 * This is either a dentry or xentry, which should be sorted in
+		 * ascending (parent ino, hash) order.
+		 */
+		inuma = key_inum(c, &sa->key);
+		inumb = key_inum(c, &sb->key);
+
+		if (inuma < inumb)
+			continue;
+		if (inuma > inumb) {
+			ubifs_err(c, "larger inum %lu goes before inum %lu",
+				  (unsigned long)inuma, (unsigned long)inumb);
+			goto error_dump;
+		}
+
+		hasha = key_block(c, &sa->key);
+		hashb = key_block(c, &sb->key);
+
+		if (hasha > hashb) {
+			ubifs_err(c, "larger hash %u goes before %u",
+				  hasha, hashb);
+			goto error_dump;
+		}
+	}
+
+	return 0;
+
+error_dump:
+	ubifs_msg(c, "dumping first node");
+	ubifs_dump_node(c, sa->node, c->leb_size - sa->offs);
+	ubifs_msg(c, "dumping second node");
+	ubifs_dump_node(c, sb->node, c->leb_size - sb->offs);
+	return -EINVAL;
+}
+
+static inline int chance(unsigned int n, unsigned int out_of)
+{
+	return !!(get_random_u32_below(out_of) + 1 <= n);
+
+}
+
+static int power_cut_emulated(struct ubifs_info *c, int lnum, int write)
+{
+	struct ubifs_debug_info *d = c->dbg;
+
+	ubifs_assert(c, dbg_is_tst_rcvry(c));
+
+	if (!d->pc_cnt) {
+		/* First call - decide delay to the power cut */
+		if (chance(1, 2)) {
+			unsigned long delay;
+
+			if (chance(1, 2)) {
+				d->pc_delay = 1;
+				/* Fail within 1 minute */
+				delay = get_random_u32_below(60000);
+				d->pc_timeout = jiffies;
+				d->pc_timeout += msecs_to_jiffies(delay);
+				ubifs_warn(c, "failing after %lums", delay);
+			} else {
+				d->pc_delay = 2;
+				delay = get_random_u32_below(10000);
+				/* Fail within 10000 operations */
+				d->pc_cnt_max = delay;
+				ubifs_warn(c, "failing after %lu calls", delay);
+			}
+		}
+
+		d->pc_cnt += 1;
+	}
+
+	/* Determine if failure delay has expired */
+	if (d->pc_delay == 1 && time_before(jiffies, d->pc_timeout))
+			return 0;
+	if (d->pc_delay == 2 && d->pc_cnt++ < d->pc_cnt_max)
+			return 0;
+
+	if (lnum == UBIFS_SB_LNUM) {
+		if (write && chance(1, 2))
+			return 0;
+		if (chance(19, 20))
+			return 0;
+		ubifs_warn(c, "failing in super block LEB %d", lnum);
+	} else if (lnum == UBIFS_MST_LNUM || lnum == UBIFS_MST_LNUM + 1) {
+		if (chance(19, 20))
+			return 0;
+		ubifs_warn(c, "failing in master LEB %d", lnum);
+	} else if (lnum >= UBIFS_LOG_LNUM && lnum <= c->log_last) {
+		if (write && chance(99, 100))
+			return 0;
+		if (chance(399, 400))
+			return 0;
+		ubifs_warn(c, "failing in log LEB %d", lnum);
+	} else if (lnum >= c->lpt_first && lnum <= c->lpt_last) {
+		if (write && chance(7, 8))
+			return 0;
+		if (chance(19, 20))
+			return 0;
+		ubifs_warn(c, "failing in LPT LEB %d", lnum);
+	} else if (lnum >= c->orph_first && lnum <= c->orph_last) {
+		if (write && chance(1, 2))
+			return 0;
+		if (chance(9, 10))
+			return 0;
+		ubifs_warn(c, "failing in orphan LEB %d", lnum);
+	} else if (lnum == c->ihead_lnum) {
+		if (chance(99, 100))
+			return 0;
+		ubifs_warn(c, "failing in index head LEB %d", lnum);
+	} else if (c->jheads && lnum == c->jheads[GCHD].wbuf.lnum) {
+		if (chance(9, 10))
+			return 0;
+		ubifs_warn(c, "failing in GC head LEB %d", lnum);
+	} else if (write && !RB_EMPTY_ROOT(&c->buds) &&
+		   !ubifs_search_bud(c, lnum)) {
+		if (chance(19, 20))
+			return 0;
+		ubifs_warn(c, "failing in non-bud LEB %d", lnum);
+	} else if (c->cmt_state == COMMIT_RUNNING_BACKGROUND ||
+		   c->cmt_state == COMMIT_RUNNING_REQUIRED) {
+		if (chance(999, 1000))
+			return 0;
+		ubifs_warn(c, "failing in bud LEB %d commit running", lnum);
+	} else {
+		if (chance(9999, 10000))
+			return 0;
+		ubifs_warn(c, "failing in bud LEB %d commit not running", lnum);
+	}
+
+	d->pc_happened = 1;
+	ubifs_warn(c, "========== Power cut emulated ==========");
+	dump_stack();
+	return 1;
+}
+
+static int corrupt_data(const struct ubifs_info *c, const void *buf,
+			unsigned int len)
+{
+	unsigned int from, to, ffs = chance(1, 2);
+	unsigned char *p = (void *)buf;
+
+	from = get_random_u32_below(len);
+	/* Corruption span max to end of write unit */
+	to = min(len, ALIGN(from + 1, c->max_write_size));
+
+	ubifs_warn(c, "filled bytes %u-%u with %s", from, to - 1,
+		   ffs ? "0xFFs" : "random data");
+
+	if (ffs)
+		memset(p + from, 0xFF, to - from);
+	else
+		get_random_bytes(p + from, to - from);
+
+	return to;
+}
+
+int dbg_leb_write(struct ubifs_info *c, int lnum, const void *buf,
+		  int offs, int len)
+{
+	int err, failing;
+
+	if (dbg_is_power_cut(c))
+		return -EROFS;
+
+	failing = power_cut_emulated(c, lnum, 1);
+	if (failing) {
+		len = corrupt_data(c, buf, len);
+		ubifs_warn(c, "actually write %d bytes to LEB %d:%d (the buffer was corrupted)",
+			   len, lnum, offs);
+	}
+	err = ubi_leb_write(c->ubi, lnum, buf, offs, len);
+	if (err)
+		return err;
+	if (failing)
+		return -EROFS;
+	return 0;
+}
+
+int dbg_leb_change(struct ubifs_info *c, int lnum, const void *buf,
+		   int len)
+{
+	int err;
+
+	if (dbg_is_power_cut(c))
+		return -EROFS;
+	if (power_cut_emulated(c, lnum, 1))
+		return -EROFS;
+	err = ubi_leb_change(c->ubi, lnum, buf, len);
+	if (err)
+		return err;
+	if (power_cut_emulated(c, lnum, 1))
+		return -EROFS;
+	return 0;
+}
+
+int dbg_leb_unmap(struct ubifs_info *c, int lnum)
+{
+	int err;
+
+	if (dbg_is_power_cut(c))
+		return -EROFS;
+	if (power_cut_emulated(c, lnum, 0))
+		return -EROFS;
+	err = ubi_leb_unmap(c->ubi, lnum);
+	if (err)
+		return err;
+	if (power_cut_emulated(c, lnum, 0))
+		return -EROFS;
+	return 0;
+}
+
+int dbg_leb_map(struct ubifs_info *c, int lnum)
+{
+	int err;
+
+	if (dbg_is_power_cut(c))
+		return -EROFS;
+	if (power_cut_emulated(c, lnum, 0))
+		return -EROFS;
+	err = ubi_leb_map(c->ubi, lnum);
+	if (err)
+		return err;
+	if (power_cut_emulated(c, lnum, 0))
+		return -EROFS;
+	return 0;
+}
+
+/*
+ * Root directory for UBIFS stuff in debugfs. Contains sub-directories which
+ * contain the stuff specific to particular file-system mounts.
+ */
+static struct dentry *dfs_rootdir;
+
+static int dfs_file_open(struct inode *inode, struct file *file)
+{
+	file->private_data = inode->i_private;
+	return nonseekable_open(inode, file);
+}
+
+/**
+ * provide_user_output - provide output to the user reading a debugfs file.
+ * @val: boolean value for the answer
+ * @u: the buffer to store the answer at
+ * @count: size of the buffer
+ * @ppos: position in the @u output buffer
+ *
+ * This is a simple helper function which stores @val boolean value in the user
+ * buffer when the user reads one of UBIFS debugfs files. Returns amount of
+ * bytes written to @u in case of success and a negative error code in case of
+ * failure.
+ */
+static int provide_user_output(int val, char __user *u, size_t count,
+			       loff_t *ppos)
+{
+	char buf[3];
+
+	if (val)
+		buf[0] = '1';
+	else
+		buf[0] = '0';
+	buf[1] = '\n';
+	buf[2] = 0x00;
+
+	return simple_read_from_buffer(u, count, ppos, buf, 2);
+}
+
+static ssize_t dfs_file_read(struct file *file, char __user *u, size_t count,
+			     loff_t *ppos)
+{
+	struct dentry *dent = file->f_path.dentry;
+	struct ubifs_info *c = file->private_data;
+	struct ubifs_debug_info *d = c->dbg;
+	int val;
+
+	if (dent == d->dfs_chk_gen)
+		val = d->chk_gen;
+	else if (dent == d->dfs_chk_index)
+		val = d->chk_index;
+	else if (dent == d->dfs_chk_orph)
+		val = d->chk_orph;
+	else if (dent == d->dfs_chk_lprops)
+		val = d->chk_lprops;
+	else if (dent == d->dfs_chk_fs)
+		val = d->chk_fs;
+	else if (dent == d->dfs_tst_rcvry)
+		val = d->tst_rcvry;
+	else if (dent == d->dfs_ro_error)
+		val = c->ro_error;
+	else
+		return -EINVAL;
+
+	return provide_user_output(val, u, count, ppos);
+}
+
+/**
+ * interpret_user_input - interpret user debugfs file input.
+ * @u: user-provided buffer with the input
+ * @count: buffer size
+ *
+ * This is a helper function which interpret user input to a boolean UBIFS
+ * debugfs file. Returns %0 or %1 in case of success and a negative error code
+ * in case of failure.
+ */
+static int interpret_user_input(const char __user *u, size_t count)
+{
+	size_t buf_size;
+	char buf[8];
+
+	buf_size = min_t(size_t, count, (sizeof(buf) - 1));
+	if (copy_from_user(buf, u, buf_size))
+		return -EFAULT;
+
+	if (buf[0] == '1')
+		return 1;
+	else if (buf[0] == '0')
+		return 0;
+
+	return -EINVAL;
+}
+
+static ssize_t dfs_file_write(struct file *file, const char __user *u,
+			      size_t count, loff_t *ppos)
+{
+	struct ubifs_info *c = file->private_data;
+	struct ubifs_debug_info *d = c->dbg;
+	struct dentry *dent = file->f_path.dentry;
+	int val;
+
+	if (file->f_path.dentry == d->dfs_dump_lprops) {
+		ubifs_dump_lprops(c);
+		return count;
+	}
+	if (file->f_path.dentry == d->dfs_dump_budg) {
+		ubifs_dump_budg(c, &c->bi);
+		return count;
+	}
+	if (file->f_path.dentry == d->dfs_dump_tnc) {
+		mutex_lock(&c->tnc_mutex);
+		ubifs_dump_tnc(c);
+		mutex_unlock(&c->tnc_mutex);
+		return count;
+	}
+
+	val = interpret_user_input(u, count);
+	if (val < 0)
+		return val;
+
+	if (dent == d->dfs_chk_gen)
+		d->chk_gen = val;
+	else if (dent == d->dfs_chk_index)
+		d->chk_index = val;
+	else if (dent == d->dfs_chk_orph)
+		d->chk_orph = val;
+	else if (dent == d->dfs_chk_lprops)
+		d->chk_lprops = val;
+	else if (dent == d->dfs_chk_fs)
+		d->chk_fs = val;
+	else if (dent == d->dfs_tst_rcvry)
+		d->tst_rcvry = val;
+	else if (dent == d->dfs_ro_error)
+		c->ro_error = !!val;
+	else
+		return -EINVAL;
+
+	return count;
+}
+
+static const struct file_operations dfs_fops = {
+	.open = dfs_file_open,
+	.read = dfs_file_read,
+	.write = dfs_file_write,
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+};
+
+/**
+ * dbg_debugfs_init_fs - initialize debugfs for UBIFS instance.
+ * @c: UBIFS file-system description object
+ *
+ * This function creates all debugfs files for this instance of UBIFS.
+ *
+ * Note, the only reason we have not merged this function with the
+ * 'ubifs_debugging_init()' function is because it is better to initialize
+ * debugfs interfaces at the very end of the mount process, and remove them at
+ * the very beginning of the mount process.
+ */
+void dbg_debugfs_init_fs(struct ubifs_info *c)
+{
+	int n;
+	const char *fname;
+	struct ubifs_debug_info *d = c->dbg;
+
+	n = snprintf(d->dfs_dir_name, UBIFS_DFS_DIR_LEN + 1, UBIFS_DFS_DIR_NAME,
+		     c->vi.ubi_num, c->vi.vol_id);
+	if (n > UBIFS_DFS_DIR_LEN) {
+		/* The array size is too small */
+		return;
+	}
+
+	fname = d->dfs_dir_name;
+	d->dfs_dir = debugfs_create_dir(fname, dfs_rootdir);
+
+	fname = "dump_lprops";
+	d->dfs_dump_lprops = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, c,
+						 &dfs_fops);
+
+	fname = "dump_budg";
+	d->dfs_dump_budg = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, c,
+					       &dfs_fops);
+
+	fname = "dump_tnc";
+	d->dfs_dump_tnc = debugfs_create_file(fname, S_IWUSR, d->dfs_dir, c,
+					      &dfs_fops);
+
+	fname = "chk_general";
+	d->dfs_chk_gen = debugfs_create_file(fname, S_IRUSR | S_IWUSR,
+					     d->dfs_dir, c, &dfs_fops);
+
+	fname = "chk_index";
+	d->dfs_chk_index = debugfs_create_file(fname, S_IRUSR | S_IWUSR,
+					       d->dfs_dir, c, &dfs_fops);
+
+	fname = "chk_orphans";
+	d->dfs_chk_orph = debugfs_create_file(fname, S_IRUSR | S_IWUSR,
+					      d->dfs_dir, c, &dfs_fops);
+
+	fname = "chk_lprops";
+	d->dfs_chk_lprops = debugfs_create_file(fname, S_IRUSR | S_IWUSR,
+						d->dfs_dir, c, &dfs_fops);
+
+	fname = "chk_fs";
+	d->dfs_chk_fs = debugfs_create_file(fname, S_IRUSR | S_IWUSR,
+					    d->dfs_dir, c, &dfs_fops);
+
+	fname = "tst_recovery";
+	d->dfs_tst_rcvry = debugfs_create_file(fname, S_IRUSR | S_IWUSR,
+					       d->dfs_dir, c, &dfs_fops);
+
+	fname = "ro_error";
+	d->dfs_ro_error = debugfs_create_file(fname, S_IRUSR | S_IWUSR,
+					      d->dfs_dir, c, &dfs_fops);
+}
+
+/**
+ * dbg_debugfs_exit_fs - remove all debugfs files.
+ * @c: UBIFS file-system description object
+ */
+void dbg_debugfs_exit_fs(struct ubifs_info *c)
+{
+	debugfs_remove_recursive(c->dbg->dfs_dir);
+}
+
+struct ubifs_global_debug_info ubifs_dbg;
+
+static struct dentry *dfs_chk_gen;
+static struct dentry *dfs_chk_index;
+static struct dentry *dfs_chk_orph;
+static struct dentry *dfs_chk_lprops;
+static struct dentry *dfs_chk_fs;
+static struct dentry *dfs_tst_rcvry;
+
+static ssize_t dfs_global_file_read(struct file *file, char __user *u,
+				    size_t count, loff_t *ppos)
+{
+	struct dentry *dent = file->f_path.dentry;
+	int val;
+
+	if (dent == dfs_chk_gen)
+		val = ubifs_dbg.chk_gen;
+	else if (dent == dfs_chk_index)
+		val = ubifs_dbg.chk_index;
+	else if (dent == dfs_chk_orph)
+		val = ubifs_dbg.chk_orph;
+	else if (dent == dfs_chk_lprops)
+		val = ubifs_dbg.chk_lprops;
+	else if (dent == dfs_chk_fs)
+		val = ubifs_dbg.chk_fs;
+	else if (dent == dfs_tst_rcvry)
+		val = ubifs_dbg.tst_rcvry;
+	else
+		return -EINVAL;
+
+	return provide_user_output(val, u, count, ppos);
+}
+
+static ssize_t dfs_global_file_write(struct file *file, const char __user *u,
+				     size_t count, loff_t *ppos)
+{
+	struct dentry *dent = file->f_path.dentry;
+	int val;
+
+	val = interpret_user_input(u, count);
+	if (val < 0)
+		return val;
+
+	if (dent == dfs_chk_gen)
+		ubifs_dbg.chk_gen = val;
+	else if (dent == dfs_chk_index)
+		ubifs_dbg.chk_index = val;
+	else if (dent == dfs_chk_orph)
+		ubifs_dbg.chk_orph = val;
+	else if (dent == dfs_chk_lprops)
+		ubifs_dbg.chk_lprops = val;
+	else if (dent == dfs_chk_fs)
+		ubifs_dbg.chk_fs = val;
+	else if (dent == dfs_tst_rcvry)
+		ubifs_dbg.tst_rcvry = val;
+	else
+		return -EINVAL;
+
+	return count;
+}
+
+static const struct file_operations dfs_global_fops = {
+	.read = dfs_global_file_read,
+	.write = dfs_global_file_write,
+	.owner = THIS_MODULE,
+	.llseek = no_llseek,
+};
+
+/**
+ * dbg_debugfs_init - initialize debugfs file-system.
+ *
+ * UBIFS uses debugfs file-system to expose various debugging knobs to
+ * user-space. This function creates "ubifs" directory in the debugfs
+ * file-system.
+ */
+void dbg_debugfs_init(void)
+{
+	const char *fname;
+
+	fname = "ubifs";
+	dfs_rootdir = debugfs_create_dir(fname, NULL);
+
+	fname = "chk_general";
+	dfs_chk_gen = debugfs_create_file(fname, S_IRUSR | S_IWUSR, dfs_rootdir,
+					  NULL, &dfs_global_fops);
+
+	fname = "chk_index";
+	dfs_chk_index = debugfs_create_file(fname, S_IRUSR | S_IWUSR,
+					    dfs_rootdir, NULL, &dfs_global_fops);
+
+	fname = "chk_orphans";
+	dfs_chk_orph = debugfs_create_file(fname, S_IRUSR | S_IWUSR,
+					   dfs_rootdir, NULL, &dfs_global_fops);
+
+	fname = "chk_lprops";
+	dfs_chk_lprops = debugfs_create_file(fname, S_IRUSR | S_IWUSR,
+					     dfs_rootdir, NULL, &dfs_global_fops);
+
+	fname = "chk_fs";
+	dfs_chk_fs = debugfs_create_file(fname, S_IRUSR | S_IWUSR, dfs_rootdir,
+					 NULL, &dfs_global_fops);
+
+	fname = "tst_recovery";
+	dfs_tst_rcvry = debugfs_create_file(fname, S_IRUSR | S_IWUSR,
+					    dfs_rootdir, NULL, &dfs_global_fops);
+}
+
+/**
+ * dbg_debugfs_exit - remove the "ubifs" directory from debugfs file-system.
+ */
+void dbg_debugfs_exit(void)
+{
+	debugfs_remove_recursive(dfs_rootdir);
+}
+
+void ubifs_assert_failed(struct ubifs_info *c, const char *expr,
+			 const char *file, int line)
+{
+	ubifs_err(c, "UBIFS assert failed: %s, in %s:%u", expr, file, line);
+
+	switch (c->assert_action) {
+		case ASSACT_PANIC:
+		BUG();
+		break;
+
+		case ASSACT_RO:
+		ubifs_ro_mode(c, -EINVAL);
+		break;
+
+		case ASSACT_REPORT:
+		default:
+		dump_stack();
+		break;
+
+	}
+}
+
+/**
+ * ubifs_debugging_init - initialize UBIFS debugging.
+ * @c: UBIFS file-system description object
+ *
+ * This function initializes debugging-related data for the file system.
+ * Returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+int ubifs_debugging_init(struct ubifs_info *c)
+{
+	c->dbg = kzalloc(sizeof(struct ubifs_debug_info), GFP_KERNEL);
+	if (!c->dbg)
+		return -ENOMEM;
+
+	return 0;
+}
+
+/**
+ * ubifs_debugging_exit - free debugging data.
+ * @c: UBIFS file-system description object
+ */
+void ubifs_debugging_exit(struct ubifs_info *c)
+{
+	kfree(c->dbg);
+}
diff --git a/ubifs-utils/libubifs/debug.h b/ubifs-utils/libubifs/debug.h
new file mode 100644
index 00000000..ed966108
--- /dev/null
+++ b/ubifs-utils/libubifs/debug.h
@@ -0,0 +1,304 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ */
+
+#ifndef __UBIFS_DEBUG_H__
+#define __UBIFS_DEBUG_H__
+
+/* Checking helper functions */
+typedef int (*dbg_leaf_callback)(struct ubifs_info *c,
+				 struct ubifs_zbranch *zbr, void *priv);
+typedef int (*dbg_znode_callback)(struct ubifs_info *c,
+				  struct ubifs_znode *znode, void *priv);
+
+/*
+ * The UBIFS debugfs directory name pattern and maximum name length (3 for "ubi"
+ * + 1 for "_" and plus 2x2 for 2 UBI numbers and 1 for the trailing zero byte.
+ */
+#define UBIFS_DFS_DIR_NAME "ubi%d_%d"
+#define UBIFS_DFS_DIR_LEN  (3 + 1 + 2*2 + 1)
+
+/**
+ * ubifs_debug_info - per-FS debugging information.
+ * @old_zroot: old index root - used by 'dbg_check_old_index()'
+ * @old_zroot_level: old index root level - used by 'dbg_check_old_index()'
+ * @old_zroot_sqnum: old index root sqnum - used by 'dbg_check_old_index()'
+ *
+ * @pc_happened: non-zero if an emulated power cut happened
+ * @pc_delay: 0=>don't delay, 1=>delay a time, 2=>delay a number of calls
+ * @pc_timeout: time in jiffies when delay of failure mode expires
+ * @pc_cnt: current number of calls to failure mode I/O functions
+ * @pc_cnt_max: number of calls by which to delay failure mode
+ *
+ * @chk_lpt_sz: used by LPT tree size checker
+ * @chk_lpt_sz2: used by LPT tree size checker
+ * @chk_lpt_wastage: used by LPT tree size checker
+ * @chk_lpt_lebs: used by LPT tree size checker
+ * @new_nhead_offs: used by LPT tree size checker
+ * @new_ihead_lnum: used by debugging to check @c->ihead_lnum
+ * @new_ihead_offs: used by debugging to check @c->ihead_offs
+ *
+ * @saved_lst: saved lprops statistics (used by 'dbg_save_space_info()')
+ * @saved_bi: saved budgeting information
+ * @saved_free: saved amount of free space
+ * @saved_idx_gc_cnt: saved value of @c->idx_gc_cnt
+ *
+ * @chk_gen: if general extra checks are enabled
+ * @chk_index: if index xtra checks are enabled
+ * @chk_orph: if orphans extra checks are enabled
+ * @chk_lprops: if lprops extra checks are enabled
+ * @chk_fs: if UBIFS contents extra checks are enabled
+ * @tst_rcvry: if UBIFS recovery testing mode enabled
+ *
+ * @dfs_dir_name: name of debugfs directory containing this file-system's files
+ * @dfs_dir: direntry object of the file-system debugfs directory
+ * @dfs_dump_lprops: "dump lprops" debugfs knob
+ * @dfs_dump_budg: "dump budgeting information" debugfs knob
+ * @dfs_dump_tnc: "dump TNC" debugfs knob
+ * @dfs_chk_gen: debugfs knob to enable UBIFS general extra checks
+ * @dfs_chk_index: debugfs knob to enable UBIFS index extra checks
+ * @dfs_chk_orph: debugfs knob to enable UBIFS orphans extra checks
+ * @dfs_chk_lprops: debugfs knob to enable UBIFS LEP properties extra checks
+ * @dfs_chk_fs: debugfs knob to enable UBIFS contents extra checks
+ * @dfs_tst_rcvry: debugfs knob to enable UBIFS recovery testing
+ * @dfs_ro_error: debugfs knob to switch UBIFS to R/O mode (different to
+ *                re-mounting to R/O mode because it does not flush any buffers
+ *                and UBIFS just starts returning -EROFS on all write
+ *               operations)
+ */
+struct ubifs_debug_info {
+	struct ubifs_zbranch old_zroot;
+	int old_zroot_level;
+	unsigned long long old_zroot_sqnum;
+
+	int pc_happened;
+	int pc_delay;
+	unsigned long pc_timeout;
+	unsigned int pc_cnt;
+	unsigned int pc_cnt_max;
+
+	long long chk_lpt_sz;
+	long long chk_lpt_sz2;
+	long long chk_lpt_wastage;
+	int chk_lpt_lebs;
+	int new_nhead_offs;
+	int new_ihead_lnum;
+	int new_ihead_offs;
+
+	struct ubifs_lp_stats saved_lst;
+	struct ubifs_budg_info saved_bi;
+	long long saved_free;
+	int saved_idx_gc_cnt;
+
+	unsigned int chk_gen:1;
+	unsigned int chk_index:1;
+	unsigned int chk_orph:1;
+	unsigned int chk_lprops:1;
+	unsigned int chk_fs:1;
+	unsigned int tst_rcvry:1;
+
+	char dfs_dir_name[UBIFS_DFS_DIR_LEN + 1];
+	struct dentry *dfs_dir;
+	struct dentry *dfs_dump_lprops;
+	struct dentry *dfs_dump_budg;
+	struct dentry *dfs_dump_tnc;
+	struct dentry *dfs_chk_gen;
+	struct dentry *dfs_chk_index;
+	struct dentry *dfs_chk_orph;
+	struct dentry *dfs_chk_lprops;
+	struct dentry *dfs_chk_fs;
+	struct dentry *dfs_tst_rcvry;
+	struct dentry *dfs_ro_error;
+};
+
+/**
+ * ubifs_global_debug_info - global (not per-FS) UBIFS debugging information.
+ *
+ * @chk_gen: if general extra checks are enabled
+ * @chk_index: if index xtra checks are enabled
+ * @chk_orph: if orphans extra checks are enabled
+ * @chk_lprops: if lprops extra checks are enabled
+ * @chk_fs: if UBIFS contents extra checks are enabled
+ * @tst_rcvry: if UBIFS recovery testing mode enabled
+ */
+struct ubifs_global_debug_info {
+	unsigned int chk_gen:1;
+	unsigned int chk_index:1;
+	unsigned int chk_orph:1;
+	unsigned int chk_lprops:1;
+	unsigned int chk_fs:1;
+	unsigned int tst_rcvry:1;
+};
+
+void ubifs_assert_failed(struct ubifs_info *c, const char *expr,
+	const char *file, int line);
+
+#define ubifs_assert(c, expr) do {                                             \
+	if (unlikely(!(expr))) {                                               \
+		ubifs_assert_failed((struct ubifs_info *)c, #expr, __FILE__,   \
+		 __LINE__);                                                    \
+	}                                                                      \
+} while (0)
+
+#define ubifs_assert_cmt_locked(c) do {                                        \
+	if (unlikely(down_write_trylock(&(c)->commit_sem))) {                  \
+		up_write(&(c)->commit_sem);                                    \
+		ubifs_err(c, "commit lock is not locked!\n");                  \
+		ubifs_assert(c, 0);                                            \
+	}                                                                      \
+} while (0)
+
+#define ubifs_dbg_msg(type, fmt, ...) \
+	pr_debug("UBIFS DBG " type " (pid %d): " fmt "\n", current->pid,       \
+		 ##__VA_ARGS__)
+
+#define DBG_KEY_BUF_LEN 48
+#define ubifs_dbg_msg_key(type, key, fmt, ...) do {                            \
+	char __tmp_key_buf[DBG_KEY_BUF_LEN];                                   \
+	pr_debug("UBIFS DBG " type " (pid %d): " fmt "%s\n", current->pid,     \
+		 ##__VA_ARGS__,                                                \
+		 dbg_snprintf_key(c, key, __tmp_key_buf, DBG_KEY_BUF_LEN));    \
+} while (0)
+
+/* General messages */
+#define dbg_gen(fmt, ...)   ubifs_dbg_msg("gen", fmt, ##__VA_ARGS__)
+/* Additional journal messages */
+#define dbg_jnl(fmt, ...)   ubifs_dbg_msg("jnl", fmt, ##__VA_ARGS__)
+#define dbg_jnlk(key, fmt, ...) \
+	ubifs_dbg_msg_key("jnl", key, fmt, ##__VA_ARGS__)
+/* Additional TNC messages */
+#define dbg_tnc(fmt, ...)   ubifs_dbg_msg("tnc", fmt, ##__VA_ARGS__)
+#define dbg_tnck(key, fmt, ...) \
+	ubifs_dbg_msg_key("tnc", key, fmt, ##__VA_ARGS__)
+/* Additional lprops messages */
+#define dbg_lp(fmt, ...)    ubifs_dbg_msg("lp", fmt, ##__VA_ARGS__)
+/* Additional LEB find messages */
+#define dbg_find(fmt, ...)  ubifs_dbg_msg("find", fmt, ##__VA_ARGS__)
+/* Additional mount messages */
+#define dbg_mnt(fmt, ...)   ubifs_dbg_msg("mnt", fmt, ##__VA_ARGS__)
+#define dbg_mntk(key, fmt, ...) \
+	ubifs_dbg_msg_key("mnt", key, fmt, ##__VA_ARGS__)
+/* Additional I/O messages */
+#define dbg_io(fmt, ...)    ubifs_dbg_msg("io", fmt, ##__VA_ARGS__)
+/* Additional commit messages */
+#define dbg_cmt(fmt, ...)   ubifs_dbg_msg("cmt", fmt, ##__VA_ARGS__)
+/* Additional budgeting messages */
+#define dbg_budg(fmt, ...)  ubifs_dbg_msg("budg", fmt, ##__VA_ARGS__)
+/* Additional log messages */
+#define dbg_log(fmt, ...)   ubifs_dbg_msg("log", fmt, ##__VA_ARGS__)
+/* Additional gc messages */
+#define dbg_gc(fmt, ...)    ubifs_dbg_msg("gc", fmt, ##__VA_ARGS__)
+/* Additional scan messages */
+#define dbg_scan(fmt, ...)  ubifs_dbg_msg("scan", fmt, ##__VA_ARGS__)
+/* Additional recovery messages */
+#define dbg_rcvry(fmt, ...) ubifs_dbg_msg("rcvry", fmt, ##__VA_ARGS__)
+
+extern struct ubifs_global_debug_info ubifs_dbg;
+
+static inline int dbg_is_chk_gen(const struct ubifs_info *c)
+{
+	return !!(ubifs_dbg.chk_gen || c->dbg->chk_gen);
+}
+static inline int dbg_is_chk_index(const struct ubifs_info *c)
+{
+	return !!(ubifs_dbg.chk_index || c->dbg->chk_index);
+}
+static inline int dbg_is_chk_orph(const struct ubifs_info *c)
+{
+	return !!(ubifs_dbg.chk_orph || c->dbg->chk_orph);
+}
+static inline int dbg_is_chk_lprops(const struct ubifs_info *c)
+{
+	return !!(ubifs_dbg.chk_lprops || c->dbg->chk_lprops);
+}
+static inline int dbg_is_chk_fs(const struct ubifs_info *c)
+{
+	return !!(ubifs_dbg.chk_fs || c->dbg->chk_fs);
+}
+static inline int dbg_is_tst_rcvry(const struct ubifs_info *c)
+{
+	return !!(ubifs_dbg.tst_rcvry || c->dbg->tst_rcvry);
+}
+static inline int dbg_is_power_cut(const struct ubifs_info *c)
+{
+	return !!c->dbg->pc_happened;
+}
+
+int ubifs_debugging_init(struct ubifs_info *c);
+void ubifs_debugging_exit(struct ubifs_info *c);
+
+/* Dump functions */
+const char *dbg_ntype(int type);
+const char *dbg_cstate(int cmt_state);
+const char *dbg_jhead(int jhead);
+const char *dbg_get_key_dump(const struct ubifs_info *c,
+			     const union ubifs_key *key);
+const char *dbg_snprintf_key(const struct ubifs_info *c,
+			     const union ubifs_key *key, char *buffer, int len);
+void ubifs_dump_inode(struct ubifs_info *c, const struct inode *inode);
+void ubifs_dump_node(const struct ubifs_info *c, const void *node,
+		     int node_len);
+void ubifs_dump_budget_req(const struct ubifs_budget_req *req);
+void ubifs_dump_lstats(const struct ubifs_lp_stats *lst);
+void ubifs_dump_budg(struct ubifs_info *c, const struct ubifs_budg_info *bi);
+void ubifs_dump_lprop(const struct ubifs_info *c,
+		      const struct ubifs_lprops *lp);
+void ubifs_dump_lprops(struct ubifs_info *c);
+void ubifs_dump_lpt_info(struct ubifs_info *c);
+void ubifs_dump_leb(const struct ubifs_info *c, int lnum);
+void ubifs_dump_znode(const struct ubifs_info *c,
+		      const struct ubifs_znode *znode);
+void ubifs_dump_heap(struct ubifs_info *c, struct ubifs_lpt_heap *heap,
+		     int cat);
+void ubifs_dump_pnode(struct ubifs_info *c, struct ubifs_pnode *pnode,
+		      struct ubifs_nnode *parent, int iip);
+void ubifs_dump_tnc(struct ubifs_info *c);
+void ubifs_dump_index(struct ubifs_info *c);
+void ubifs_dump_lpt_lebs(const struct ubifs_info *c);
+
+int dbg_walk_index(struct ubifs_info *c, dbg_leaf_callback leaf_cb,
+		   dbg_znode_callback znode_cb, void *priv);
+
+/* Checking functions */
+void dbg_save_space_info(struct ubifs_info *c);
+int dbg_check_space_info(struct ubifs_info *c);
+int dbg_check_lprops(struct ubifs_info *c);
+int dbg_old_index_check_init(struct ubifs_info *c, struct ubifs_zbranch *zroot);
+int dbg_check_old_index(struct ubifs_info *c, struct ubifs_zbranch *zroot);
+int dbg_check_cats(struct ubifs_info *c);
+int dbg_check_ltab(struct ubifs_info *c);
+int dbg_chk_lpt_free_spc(struct ubifs_info *c);
+int dbg_chk_lpt_sz(struct ubifs_info *c, int action, int len);
+int dbg_check_synced_i_size(const struct ubifs_info *c, struct inode *inode);
+int dbg_check_dir(struct ubifs_info *c, const struct inode *dir);
+int dbg_check_tnc(struct ubifs_info *c, int extra);
+int dbg_check_idx_size(struct ubifs_info *c, long long idx_size);
+int dbg_check_filesystem(struct ubifs_info *c);
+void dbg_check_heap(struct ubifs_info *c, struct ubifs_lpt_heap *heap, int cat,
+		    int add_pos);
+int dbg_check_lpt_nodes(struct ubifs_info *c, struct ubifs_cnode *cnode,
+			int row, int col);
+int dbg_check_inode_size(struct ubifs_info *c, const struct inode *inode,
+			 loff_t size);
+int dbg_check_data_nodes_order(struct ubifs_info *c, struct list_head *head);
+int dbg_check_nondata_nodes_order(struct ubifs_info *c, struct list_head *head);
+
+int dbg_leb_write(struct ubifs_info *c, int lnum, const void *buf, int offs,
+		  int len);
+int dbg_leb_change(struct ubifs_info *c, int lnum, const void *buf, int len);
+int dbg_leb_unmap(struct ubifs_info *c, int lnum);
+int dbg_leb_map(struct ubifs_info *c, int lnum);
+
+/* Debugfs-related stuff */
+void dbg_debugfs_init(void);
+void dbg_debugfs_exit(void);
+void dbg_debugfs_init_fs(struct ubifs_info *c);
+void dbg_debugfs_exit_fs(struct ubifs_info *c);
+
+#endif /* !__UBIFS_DEBUG_H__ */
diff --git a/ubifs-utils/libubifs/dir.c b/ubifs-utils/libubifs/dir.c
new file mode 100644
index 00000000..c77ea57f
--- /dev/null
+++ b/ubifs-utils/libubifs/dir.c
@@ -0,0 +1,1744 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ * Copyright (C) 2006, 2007 University of Szeged, Hungary
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ *          Zoltan Sogor
+ */
+
+/*
+ * This file implements directory operations.
+ *
+ * All FS operations in this file allocate budget before writing anything to the
+ * media. If they fail to allocate it, the error is returned. The only
+ * exceptions are 'ubifs_unlink()' and 'ubifs_rmdir()' which keep working even
+ * if they unable to allocate the budget, because deletion %-ENOSPC failure is
+ * not what users are usually ready to get. UBIFS budgeting subsystem has some
+ * space reserved for these purposes.
+ *
+ * All operations in this file write all inodes which they change straight
+ * away, instead of marking them dirty. For example, 'ubifs_link()' changes
+ * @i_size of the parent inode and writes the parent inode together with the
+ * target inode. This was done to simplify file-system recovery which would
+ * otherwise be very difficult to do. The only exception is rename which marks
+ * the re-named inode dirty (because its @i_ctime is updated) but does not
+ * write it, but just marks it as dirty.
+ */
+
+#include "ubifs.h"
+
+/**
+ * inherit_flags - inherit flags of the parent inode.
+ * @dir: parent inode
+ * @mode: new inode mode flags
+ *
+ * This is a helper function for 'ubifs_new_inode()' which inherits flag of the
+ * parent directory inode @dir. UBIFS inodes inherit the following flags:
+ * o %UBIFS_COMPR_FL, which is useful to switch compression on/of on
+ *   sub-directory basis;
+ * o %UBIFS_SYNC_FL - useful for the same reasons;
+ * o %UBIFS_DIRSYNC_FL - similar, but relevant only to directories.
+ *
+ * This function returns the inherited flags.
+ */
+static int inherit_flags(const struct inode *dir, umode_t mode)
+{
+	int flags;
+	const struct ubifs_inode *ui = ubifs_inode(dir);
+
+	if (!S_ISDIR(dir->i_mode))
+		/*
+		 * The parent is not a directory, which means that an extended
+		 * attribute inode is being created. No flags.
+		 */
+		return 0;
+
+	flags = ui->flags & (UBIFS_COMPR_FL | UBIFS_SYNC_FL | UBIFS_DIRSYNC_FL);
+	if (!S_ISDIR(mode))
+		/* The "DIRSYNC" flag only applies to directories */
+		flags &= ~UBIFS_DIRSYNC_FL;
+	return flags;
+}
+
+/**
+ * ubifs_new_inode - allocate new UBIFS inode object.
+ * @c: UBIFS file-system description object
+ * @dir: parent directory inode
+ * @mode: inode mode flags
+ * @is_xattr: whether the inode is xattr inode
+ *
+ * This function finds an unused inode number, allocates new inode and
+ * initializes it. Non-xattr new inode may be written with xattrs(selinux/
+ * encryption) before writing dentry, which could cause inconsistent problem
+ * when powercut happens between two operations. To deal with it, non-xattr
+ * new inode is initialized with zero-nlink and added into orphan list, caller
+ * should make sure that inode is relinked later, and make sure that orphan
+ * removing and journal writing into an committing atomic operation. Returns
+ * new inode in case of success and an error code in case of failure.
+ */
+struct inode *ubifs_new_inode(struct ubifs_info *c, struct inode *dir,
+			      umode_t mode, bool is_xattr)
+{
+	int err;
+	struct inode *inode;
+	struct ubifs_inode *ui;
+	bool encrypted = false;
+
+	inode = new_inode(c->vfs_sb);
+	ui = ubifs_inode(inode);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+
+	/*
+	 * Set 'S_NOCMTIME' to prevent VFS form updating [mc]time of inodes and
+	 * marking them dirty in file write path (see 'file_update_time()').
+	 * UBIFS has to fully control "clean <-> dirty" transitions of inodes
+	 * to make budgeting work.
+	 */
+	inode->i_flags |= S_NOCMTIME;
+
+	inode_init_owner(&nop_mnt_idmap, inode, dir, mode);
+	simple_inode_init_ts(inode);
+	inode->i_mapping->nrpages = 0;
+
+	if (!is_xattr) {
+		err = fscrypt_prepare_new_inode(dir, inode, &encrypted);
+		if (err) {
+			ubifs_err(c, "fscrypt_prepare_new_inode failed: %i", err);
+			goto out_iput;
+		}
+	}
+
+	switch (mode & S_IFMT) {
+	case S_IFREG:
+		inode->i_mapping->a_ops = &ubifs_file_address_operations;
+		inode->i_op = &ubifs_file_inode_operations;
+		inode->i_fop = &ubifs_file_operations;
+		break;
+	case S_IFDIR:
+		inode->i_op  = &ubifs_dir_inode_operations;
+		inode->i_fop = &ubifs_dir_operations;
+		inode->i_size = ui->ui_size = UBIFS_INO_NODE_SZ;
+		break;
+	case S_IFLNK:
+		inode->i_op = &ubifs_symlink_inode_operations;
+		break;
+	case S_IFSOCK:
+	case S_IFIFO:
+	case S_IFBLK:
+	case S_IFCHR:
+		inode->i_op  = &ubifs_file_inode_operations;
+		break;
+	default:
+		BUG();
+	}
+
+	ui->flags = inherit_flags(dir, mode);
+	ubifs_set_inode_flags(inode);
+	if (S_ISREG(mode))
+		ui->compr_type = c->default_compr;
+	else
+		ui->compr_type = UBIFS_COMPR_NONE;
+	ui->synced_i_size = 0;
+
+	spin_lock(&c->cnt_lock);
+	/* Inode number overflow is currently not supported */
+	if (c->highest_inum >= INUM_WARN_WATERMARK) {
+		if (c->highest_inum >= INUM_WATERMARK) {
+			spin_unlock(&c->cnt_lock);
+			ubifs_err(c, "out of inode numbers");
+			err = -EINVAL;
+			goto out_iput;
+		}
+		ubifs_warn(c, "running out of inode numbers (current %lu, max %u)",
+			   (unsigned long)c->highest_inum, INUM_WATERMARK);
+	}
+
+	inode->i_ino = ++c->highest_inum;
+	/*
+	 * The creation sequence number remains with this inode for its
+	 * lifetime. All nodes for this inode have a greater sequence number,
+	 * and so it is possible to distinguish obsolete nodes belonging to a
+	 * previous incarnation of the same inode number - for example, for the
+	 * purpose of rebuilding the index.
+	 */
+	ui->creat_sqnum = ++c->max_sqnum;
+	spin_unlock(&c->cnt_lock);
+
+	if (!is_xattr) {
+		set_nlink(inode, 0);
+		err = ubifs_add_orphan(c, inode->i_ino);
+		if (err) {
+			ubifs_err(c, "ubifs_add_orphan failed: %i", err);
+			goto out_iput;
+		}
+		down_read(&c->commit_sem);
+		ui->del_cmtno = c->cmt_no;
+		up_read(&c->commit_sem);
+	}
+
+	if (encrypted) {
+		err = fscrypt_set_context(inode, NULL);
+		if (err) {
+			if (!is_xattr) {
+				set_nlink(inode, 1);
+				ubifs_delete_orphan(c, inode->i_ino);
+			}
+			ubifs_err(c, "fscrypt_set_context failed: %i", err);
+			goto out_iput;
+		}
+	}
+
+	return inode;
+
+out_iput:
+	make_bad_inode(inode);
+	iput(inode);
+	return ERR_PTR(err);
+}
+
+static int dbg_check_name(const struct ubifs_info *c,
+			  const struct ubifs_dent_node *dent,
+			  const struct fscrypt_name *nm)
+{
+	if (!dbg_is_chk_gen(c))
+		return 0;
+	if (le16_to_cpu(dent->nlen) != fname_len(nm))
+		return -EINVAL;
+	if (memcmp(dent->name, fname_name(nm), fname_len(nm)))
+		return -EINVAL;
+	return 0;
+}
+
+static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry,
+				   unsigned int flags)
+{
+	int err;
+	union ubifs_key key;
+	struct inode *inode = NULL;
+	struct ubifs_dent_node *dent = NULL;
+	struct ubifs_info *c = dir->i_sb->s_fs_info;
+	struct fscrypt_name nm;
+
+	dbg_gen("'%pd' in dir ino %lu", dentry, dir->i_ino);
+
+	err = fscrypt_prepare_lookup(dir, dentry, &nm);
+	if (err == -ENOENT)
+		return d_splice_alias(NULL, dentry);
+	if (err)
+		return ERR_PTR(err);
+
+	if (fname_len(&nm) > UBIFS_MAX_NLEN) {
+		inode = ERR_PTR(-ENAMETOOLONG);
+		goto done;
+	}
+
+	dent = kmalloc(UBIFS_MAX_DENT_NODE_SZ, GFP_NOFS);
+	if (!dent) {
+		inode = ERR_PTR(-ENOMEM);
+		goto done;
+	}
+
+	if (fname_name(&nm) == NULL) {
+		if (nm.hash & ~UBIFS_S_KEY_HASH_MASK)
+			goto done; /* ENOENT */
+		dent_key_init_hash(c, &key, dir->i_ino, nm.hash);
+		err = ubifs_tnc_lookup_dh(c, &key, dent, nm.minor_hash);
+	} else {
+		dent_key_init(c, &key, dir->i_ino, &nm);
+		err = ubifs_tnc_lookup_nm(c, &key, dent, &nm);
+	}
+
+	if (err) {
+		if (err == -ENOENT)
+			dbg_gen("not found");
+		else
+			inode = ERR_PTR(err);
+		goto done;
+	}
+
+	if (dbg_check_name(c, dent, &nm)) {
+		inode = ERR_PTR(-EINVAL);
+		goto done;
+	}
+
+	inode = ubifs_iget(dir->i_sb, le64_to_cpu(dent->inum));
+	if (IS_ERR(inode)) {
+		/*
+		 * This should not happen. Probably the file-system needs
+		 * checking.
+		 */
+		err = PTR_ERR(inode);
+		ubifs_err(c, "dead directory entry '%pd', error %d",
+			  dentry, err);
+		ubifs_ro_mode(c, err);
+		goto done;
+	}
+
+	if (IS_ENCRYPTED(dir) &&
+	    (S_ISDIR(inode->i_mode) || S_ISLNK(inode->i_mode)) &&
+	    !fscrypt_has_permitted_context(dir, inode)) {
+		ubifs_warn(c, "Inconsistent encryption contexts: %lu/%lu",
+			   dir->i_ino, inode->i_ino);
+		iput(inode);
+		inode = ERR_PTR(-EPERM);
+	}
+
+done:
+	kfree(dent);
+	fscrypt_free_filename(&nm);
+	return d_splice_alias(inode, dentry);
+}
+
+static int ubifs_prepare_create(struct inode *dir, struct dentry *dentry,
+				struct fscrypt_name *nm)
+{
+	if (fscrypt_is_nokey_name(dentry))
+		return -ENOKEY;
+
+	return fscrypt_setup_filename(dir, &dentry->d_name, 0, nm);
+}
+
+static int ubifs_create(struct mnt_idmap *idmap, struct inode *dir,
+			struct dentry *dentry, umode_t mode, bool excl)
+{
+	struct inode *inode;
+	struct ubifs_info *c = dir->i_sb->s_fs_info;
+	struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
+					.dirtied_ino = 1 };
+	struct ubifs_inode *dir_ui = ubifs_inode(dir);
+	struct fscrypt_name nm;
+	int err, sz_change;
+
+	/*
+	 * Budget request settings: new inode, new direntry, changing the
+	 * parent directory inode.
+	 */
+
+	dbg_gen("dent '%pd', mode %#hx in dir ino %lu",
+		dentry, mode, dir->i_ino);
+
+	err = ubifs_budget_space(c, &req);
+	if (err)
+		return err;
+
+	err = ubifs_prepare_create(dir, dentry, &nm);
+	if (err)
+		goto out_budg;
+
+	sz_change = CALC_DENT_SIZE(fname_len(&nm));
+
+	inode = ubifs_new_inode(c, dir, mode, false);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto out_fname;
+	}
+
+	err = ubifs_init_security(dir, inode, &dentry->d_name);
+	if (err)
+		goto out_inode;
+
+	set_nlink(inode, 1);
+	mutex_lock(&dir_ui->ui_mutex);
+	dir->i_size += sz_change;
+	dir_ui->ui_size = dir->i_size;
+	inode_set_mtime_to_ts(dir,
+			      inode_set_ctime_to_ts(dir, inode_get_ctime(inode)));
+	err = ubifs_jnl_update(c, dir, &nm, inode, 0, 0, 1);
+	if (err)
+		goto out_cancel;
+	mutex_unlock(&dir_ui->ui_mutex);
+
+	ubifs_release_budget(c, &req);
+	fscrypt_free_filename(&nm);
+	insert_inode_hash(inode);
+	d_instantiate(dentry, inode);
+	return 0;
+
+out_cancel:
+	dir->i_size -= sz_change;
+	dir_ui->ui_size = dir->i_size;
+	mutex_unlock(&dir_ui->ui_mutex);
+	set_nlink(inode, 0);
+out_inode:
+	iput(inode);
+out_fname:
+	fscrypt_free_filename(&nm);
+out_budg:
+	ubifs_release_budget(c, &req);
+	ubifs_err(c, "cannot create regular file, error %d", err);
+	return err;
+}
+
+static struct inode *create_whiteout(struct inode *dir, struct dentry *dentry)
+{
+	int err;
+	umode_t mode = S_IFCHR | WHITEOUT_MODE;
+	struct inode *inode;
+	struct ubifs_info *c = dir->i_sb->s_fs_info;
+
+	/*
+	 * Create an inode('nlink = 1') for whiteout without updating journal,
+	 * let ubifs_jnl_rename() store it on flash to complete rename whiteout
+	 * atomically.
+	 */
+
+	dbg_gen("dent '%pd', mode %#hx in dir ino %lu",
+		dentry, mode, dir->i_ino);
+
+	inode = ubifs_new_inode(c, dir, mode, false);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto out_free;
+	}
+
+	init_special_inode(inode, inode->i_mode, WHITEOUT_DEV);
+	ubifs_assert(c, inode->i_op == &ubifs_file_inode_operations);
+
+	err = ubifs_init_security(dir, inode, &dentry->d_name);
+	if (err)
+		goto out_inode;
+
+	/* The dir size is updated by do_rename. */
+	insert_inode_hash(inode);
+
+	return inode;
+
+out_inode:
+	iput(inode);
+out_free:
+	ubifs_err(c, "cannot create whiteout file, error %d", err);
+	return ERR_PTR(err);
+}
+
+/**
+ * lock_2_inodes - a wrapper for locking two UBIFS inodes.
+ * @inode1: first inode
+ * @inode2: second inode
+ *
+ * We do not implement any tricks to guarantee strict lock ordering, because
+ * VFS has already done it for us on the @i_mutex. So this is just a simple
+ * wrapper function.
+ */
+static void lock_2_inodes(struct inode *inode1, struct inode *inode2)
+{
+	mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_1);
+	mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_2);
+}
+
+/**
+ * unlock_2_inodes - a wrapper for unlocking two UBIFS inodes.
+ * @inode1: first inode
+ * @inode2: second inode
+ */
+static void unlock_2_inodes(struct inode *inode1, struct inode *inode2)
+{
+	mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
+	mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
+}
+
+static int ubifs_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
+			 struct file *file, umode_t mode)
+{
+	struct dentry *dentry = file->f_path.dentry;
+	struct inode *inode;
+	struct ubifs_info *c = dir->i_sb->s_fs_info;
+	struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
+					.dirtied_ino = 1};
+	struct ubifs_budget_req ino_req = { .dirtied_ino = 1 };
+	struct ubifs_inode *ui;
+	int err, instantiated = 0;
+	struct fscrypt_name nm;
+
+	/*
+	 * Budget request settings: new inode, new direntry, changing the
+	 * parent directory inode.
+	 * Allocate budget separately for new dirtied inode, the budget will
+	 * be released via writeback.
+	 */
+
+	dbg_gen("dent '%pd', mode %#hx in dir ino %lu",
+		dentry, mode, dir->i_ino);
+
+	err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+	if (err)
+		return err;
+
+	err = ubifs_budget_space(c, &req);
+	if (err) {
+		fscrypt_free_filename(&nm);
+		return err;
+	}
+
+	err = ubifs_budget_space(c, &ino_req);
+	if (err) {
+		ubifs_release_budget(c, &req);
+		fscrypt_free_filename(&nm);
+		return err;
+	}
+
+	inode = ubifs_new_inode(c, dir, mode, false);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto out_budg;
+	}
+	ui = ubifs_inode(inode);
+
+	err = ubifs_init_security(dir, inode, &dentry->d_name);
+	if (err)
+		goto out_inode;
+
+	set_nlink(inode, 1);
+	mutex_lock(&ui->ui_mutex);
+	insert_inode_hash(inode);
+	d_tmpfile(file, inode);
+	ubifs_assert(c, ui->dirty);
+
+	instantiated = 1;
+	mutex_unlock(&ui->ui_mutex);
+
+	lock_2_inodes(dir, inode);
+	err = ubifs_jnl_update(c, dir, &nm, inode, 1, 0, 1);
+	if (err)
+		goto out_cancel;
+	unlock_2_inodes(dir, inode);
+
+	ubifs_release_budget(c, &req);
+	fscrypt_free_filename(&nm);
+
+	return finish_open_simple(file, 0);
+
+out_cancel:
+	unlock_2_inodes(dir, inode);
+out_inode:
+	if (!instantiated)
+		iput(inode);
+out_budg:
+	ubifs_release_budget(c, &req);
+	if (!instantiated)
+		ubifs_release_budget(c, &ino_req);
+	fscrypt_free_filename(&nm);
+	ubifs_err(c, "cannot create temporary file, error %d", err);
+	return err;
+}
+
+/**
+ * vfs_dent_type - get VFS directory entry type.
+ * @type: UBIFS directory entry type
+ *
+ * This function converts UBIFS directory entry type into VFS directory entry
+ * type.
+ */
+static unsigned int vfs_dent_type(uint8_t type)
+{
+	switch (type) {
+	case UBIFS_ITYPE_REG:
+		return DT_REG;
+	case UBIFS_ITYPE_DIR:
+		return DT_DIR;
+	case UBIFS_ITYPE_LNK:
+		return DT_LNK;
+	case UBIFS_ITYPE_BLK:
+		return DT_BLK;
+	case UBIFS_ITYPE_CHR:
+		return DT_CHR;
+	case UBIFS_ITYPE_FIFO:
+		return DT_FIFO;
+	case UBIFS_ITYPE_SOCK:
+		return DT_SOCK;
+	default:
+		BUG();
+	}
+	return 0;
+}
+
+/*
+ * The classical Unix view for directory is that it is a linear array of
+ * (name, inode number) entries. Linux/VFS assumes this model as well.
+ * Particularly, 'readdir()' call wants us to return a directory entry offset
+ * which later may be used to continue 'readdir()'ing the directory or to
+ * 'seek()' to that specific direntry. Obviously UBIFS does not really fit this
+ * model because directory entries are identified by keys, which may collide.
+ *
+ * UBIFS uses directory entry hash value for directory offsets, so
+ * 'seekdir()'/'telldir()' may not always work because of possible key
+ * collisions. But UBIFS guarantees that consecutive 'readdir()' calls work
+ * properly by means of saving full directory entry name in the private field
+ * of the file description object.
+ *
+ * This means that UBIFS cannot support NFS which requires full
+ * 'seekdir()'/'telldir()' support.
+ */
+static int ubifs_readdir(struct file *file, struct dir_context *ctx)
+{
+	int fstr_real_len = 0, err = 0;
+	struct fscrypt_name nm;
+	struct fscrypt_str fstr = {0};
+	union ubifs_key key;
+	struct ubifs_dent_node *dent;
+	struct inode *dir = file_inode(file);
+	struct ubifs_info *c = dir->i_sb->s_fs_info;
+	bool encrypted = IS_ENCRYPTED(dir);
+
+	dbg_gen("dir ino %lu, f_pos %#llx", dir->i_ino, ctx->pos);
+
+	if (ctx->pos > UBIFS_S_KEY_HASH_MASK || ctx->pos == 2)
+		/*
+		 * The directory was seek'ed to a senseless position or there
+		 * are no more entries.
+		 */
+		return 0;
+
+	if (encrypted) {
+		err = fscrypt_prepare_readdir(dir);
+		if (err)
+			return err;
+
+		err = fscrypt_fname_alloc_buffer(UBIFS_MAX_NLEN, &fstr);
+		if (err)
+			return err;
+
+		fstr_real_len = fstr.len;
+	}
+
+	if (file->f_version == 0) {
+		/*
+		 * The file was seek'ed, which means that @file->private_data
+		 * is now invalid. This may also be just the first
+		 * 'ubifs_readdir()' invocation, in which case
+		 * @file->private_data is NULL, and the below code is
+		 * basically a no-op.
+		 */
+		kfree(file->private_data);
+		file->private_data = NULL;
+	}
+
+	/*
+	 * 'generic_file_llseek()' unconditionally sets @file->f_version to
+	 * zero, and we use this for detecting whether the file was seek'ed.
+	 */
+	file->f_version = 1;
+
+	/* File positions 0 and 1 correspond to "." and ".." */
+	if (ctx->pos < 2) {
+		ubifs_assert(c, !file->private_data);
+		if (!dir_emit_dots(file, ctx)) {
+			if (encrypted)
+				fscrypt_fname_free_buffer(&fstr);
+			return 0;
+		}
+
+		/* Find the first entry in TNC and save it */
+		lowest_dent_key(c, &key, dir->i_ino);
+		fname_len(&nm) = 0;
+		dent = ubifs_tnc_next_ent(c, &key, &nm);
+		if (IS_ERR(dent)) {
+			err = PTR_ERR(dent);
+			goto out;
+		}
+
+		ctx->pos = key_hash_flash(c, &dent->key);
+		file->private_data = dent;
+	}
+
+	dent = file->private_data;
+	if (!dent) {
+		/*
+		 * The directory was seek'ed to and is now readdir'ed.
+		 * Find the entry corresponding to @ctx->pos or the closest one.
+		 */
+		dent_key_init_hash(c, &key, dir->i_ino, ctx->pos);
+		fname_len(&nm) = 0;
+		dent = ubifs_tnc_next_ent(c, &key, &nm);
+		if (IS_ERR(dent)) {
+			err = PTR_ERR(dent);
+			goto out;
+		}
+		ctx->pos = key_hash_flash(c, &dent->key);
+		file->private_data = dent;
+	}
+
+	while (1) {
+		dbg_gen("ino %llu, new f_pos %#x",
+			(unsigned long long)le64_to_cpu(dent->inum),
+			key_hash_flash(c, &dent->key));
+		ubifs_assert(c, le64_to_cpu(dent->ch.sqnum) >
+			     ubifs_inode(dir)->creat_sqnum);
+
+		fname_len(&nm) = le16_to_cpu(dent->nlen);
+		fname_name(&nm) = dent->name;
+
+		if (encrypted) {
+			fstr.len = fstr_real_len;
+
+			err = fscrypt_fname_disk_to_usr(dir, key_hash_flash(c,
+							&dent->key),
+							le32_to_cpu(dent->cookie),
+							&nm.disk_name, &fstr);
+			if (err)
+				goto out;
+		} else {
+			fstr.len = fname_len(&nm);
+			fstr.name = fname_name(&nm);
+		}
+
+		if (!dir_emit(ctx, fstr.name, fstr.len,
+			       le64_to_cpu(dent->inum),
+			       vfs_dent_type(dent->type))) {
+			if (encrypted)
+				fscrypt_fname_free_buffer(&fstr);
+			return 0;
+		}
+
+		/* Switch to the next entry */
+		key_read(c, &dent->key, &key);
+		dent = ubifs_tnc_next_ent(c, &key, &nm);
+		if (IS_ERR(dent)) {
+			err = PTR_ERR(dent);
+			goto out;
+		}
+
+		kfree(file->private_data);
+		ctx->pos = key_hash_flash(c, &dent->key);
+		file->private_data = dent;
+		cond_resched();
+	}
+
+out:
+	kfree(file->private_data);
+	file->private_data = NULL;
+
+	if (encrypted)
+		fscrypt_fname_free_buffer(&fstr);
+
+	if (err != -ENOENT)
+		ubifs_err(c, "cannot find next direntry, error %d", err);
+	else
+		/*
+		 * -ENOENT is a non-fatal error in this context, the TNC uses
+		 * it to indicate that the cursor moved past the current directory
+		 * and readdir() has to stop.
+		 */
+		err = 0;
+
+
+	/* 2 is a special value indicating that there are no more direntries */
+	ctx->pos = 2;
+	return err;
+}
+
+/* Free saved readdir() state when the directory is closed */
+static int ubifs_dir_release(struct inode *dir, struct file *file)
+{
+	kfree(file->private_data);
+	file->private_data = NULL;
+	return 0;
+}
+
+static int ubifs_link(struct dentry *old_dentry, struct inode *dir,
+		      struct dentry *dentry)
+{
+	struct ubifs_info *c = dir->i_sb->s_fs_info;
+	struct inode *inode = d_inode(old_dentry);
+	struct ubifs_inode *ui = ubifs_inode(inode);
+	struct ubifs_inode *dir_ui = ubifs_inode(dir);
+	int err, sz_change;
+	struct ubifs_budget_req req = { .new_dent = 1, .dirtied_ino = 2,
+				.dirtied_ino_d = ALIGN(ui->data_len, 8) };
+	struct fscrypt_name nm;
+
+	/*
+	 * Budget request settings: new direntry, changing the target inode,
+	 * changing the parent inode.
+	 */
+
+	dbg_gen("dent '%pd' to ino %lu (nlink %d) in dir ino %lu",
+		dentry, inode->i_ino,
+		inode->i_nlink, dir->i_ino);
+	ubifs_assert(c, inode_is_locked(dir));
+	ubifs_assert(c, inode_is_locked(inode));
+
+	err = fscrypt_prepare_link(old_dentry, dir, dentry);
+	if (err)
+		return err;
+
+	err = fscrypt_setup_filename(dir, &dentry->d_name, 0, &nm);
+	if (err)
+		return err;
+
+	sz_change = CALC_DENT_SIZE(fname_len(&nm));
+
+	err = dbg_check_synced_i_size(c, inode);
+	if (err)
+		goto out_fname;
+
+	err = ubifs_budget_space(c, &req);
+	if (err)
+		goto out_fname;
+
+	lock_2_inodes(dir, inode);
+
+	inc_nlink(inode);
+	ihold(inode);
+	inode_set_ctime_current(inode);
+	dir->i_size += sz_change;
+	dir_ui->ui_size = dir->i_size;
+	inode_set_mtime_to_ts(dir,
+			      inode_set_ctime_to_ts(dir, inode_get_ctime(inode)));
+	err = ubifs_jnl_update(c, dir, &nm, inode, 0, 0, inode->i_nlink == 1);
+	if (err)
+		goto out_cancel;
+	unlock_2_inodes(dir, inode);
+
+	ubifs_release_budget(c, &req);
+	d_instantiate(dentry, inode);
+	fscrypt_free_filename(&nm);
+	return 0;
+
+out_cancel:
+	dir->i_size -= sz_change;
+	dir_ui->ui_size = dir->i_size;
+	drop_nlink(inode);
+	unlock_2_inodes(dir, inode);
+	ubifs_release_budget(c, &req);
+	iput(inode);
+out_fname:
+	fscrypt_free_filename(&nm);
+	return err;
+}
+
+static int ubifs_unlink(struct inode *dir, struct dentry *dentry)
+{
+	struct ubifs_info *c = dir->i_sb->s_fs_info;
+	struct inode *inode = d_inode(dentry);
+	struct ubifs_inode *dir_ui = ubifs_inode(dir);
+	int err, sz_change, budgeted = 1;
+	struct ubifs_budget_req req = { .mod_dent = 1, .dirtied_ino = 2 };
+	unsigned int saved_nlink = inode->i_nlink;
+	struct fscrypt_name nm;
+
+	/*
+	 * Budget request settings: deletion direntry, deletion inode (+1 for
+	 * @dirtied_ino), changing the parent directory inode. If budgeting
+	 * fails, go ahead anyway because we have extra space reserved for
+	 * deletions.
+	 */
+
+	dbg_gen("dent '%pd' from ino %lu (nlink %d) in dir ino %lu",
+		dentry, inode->i_ino,
+		inode->i_nlink, dir->i_ino);
+
+	err = fscrypt_setup_filename(dir, &dentry->d_name, 1, &nm);
+	if (err)
+		return err;
+
+	err = ubifs_purge_xattrs(inode);
+	if (err)
+		return err;
+
+	sz_change = CALC_DENT_SIZE(fname_len(&nm));
+
+	ubifs_assert(c, inode_is_locked(dir));
+	ubifs_assert(c, inode_is_locked(inode));
+	err = dbg_check_synced_i_size(c, inode);
+	if (err)
+		goto out_fname;
+
+	err = ubifs_budget_space(c, &req);
+	if (err) {
+		if (err != -ENOSPC)
+			goto out_fname;
+		budgeted = 0;
+	}
+
+	lock_2_inodes(dir, inode);
+	inode_set_ctime_current(inode);
+	drop_nlink(inode);
+	dir->i_size -= sz_change;
+	dir_ui->ui_size = dir->i_size;
+	inode_set_mtime_to_ts(dir,
+			      inode_set_ctime_to_ts(dir, inode_get_ctime(inode)));
+	err = ubifs_jnl_update(c, dir, &nm, inode, 1, 0, 0);
+	if (err)
+		goto out_cancel;
+	unlock_2_inodes(dir, inode);
+
+	if (budgeted)
+		ubifs_release_budget(c, &req);
+	else {
+		/* We've deleted something - clean the "no space" flags */
+		c->bi.nospace = c->bi.nospace_rp = 0;
+		smp_wmb();
+	}
+	fscrypt_free_filename(&nm);
+	return 0;
+
+out_cancel:
+	dir->i_size += sz_change;
+	dir_ui->ui_size = dir->i_size;
+	set_nlink(inode, saved_nlink);
+	unlock_2_inodes(dir, inode);
+	if (budgeted)
+		ubifs_release_budget(c, &req);
+out_fname:
+	fscrypt_free_filename(&nm);
+	return err;
+}
+
+/**
+ * ubifs_check_dir_empty - check if a directory is empty or not.
+ * @dir: VFS inode object of the directory to check
+ *
+ * This function checks if directory @dir is empty. Returns zero if the
+ * directory is empty, %-ENOTEMPTY if it is not, and other negative error codes
+ * in case of errors.
+ */
+int ubifs_check_dir_empty(struct inode *dir)
+{
+	struct ubifs_info *c = dir->i_sb->s_fs_info;
+	struct fscrypt_name nm = { 0 };
+	struct ubifs_dent_node *dent;
+	union ubifs_key key;
+	int err;
+
+	lowest_dent_key(c, &key, dir->i_ino);
+	dent = ubifs_tnc_next_ent(c, &key, &nm);
+	if (IS_ERR(dent)) {
+		err = PTR_ERR(dent);
+		if (err == -ENOENT)
+			err = 0;
+	} else {
+		kfree(dent);
+		err = -ENOTEMPTY;
+	}
+	return err;
+}
+
+static int ubifs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+	struct ubifs_info *c = dir->i_sb->s_fs_info;
+	struct inode *inode = d_inode(dentry);
+	int err, sz_change, budgeted = 1;
+	struct ubifs_inode *dir_ui = ubifs_inode(dir);
+	struct ubifs_budget_req req = { .mod_dent = 1, .dirtied_ino = 2 };
+	struct fscrypt_name nm;
+
+	/*
+	 * Budget request settings: deletion direntry, deletion inode and
+	 * changing the parent inode. If budgeting fails, go ahead anyway
+	 * because we have extra space reserved for deletions.
+	 */
+
+	dbg_gen("directory '%pd', ino %lu in dir ino %lu", dentry,
+		inode->i_ino, dir->i_ino);
+	ubifs_assert(c, inode_is_locked(dir));
+	ubifs_assert(c, inode_is_locked(inode));
+	err = ubifs_check_dir_empty(d_inode(dentry));
+	if (err)
+		return err;
+
+	err = fscrypt_setup_filename(dir, &dentry->d_name, 1, &nm);
+	if (err)
+		return err;
+
+	err = ubifs_purge_xattrs(inode);
+	if (err)
+		return err;
+
+	sz_change = CALC_DENT_SIZE(fname_len(&nm));
+
+	err = ubifs_budget_space(c, &req);
+	if (err) {
+		if (err != -ENOSPC)
+			goto out_fname;
+		budgeted = 0;
+	}
+
+	lock_2_inodes(dir, inode);
+	inode_set_ctime_current(inode);
+	clear_nlink(inode);
+	drop_nlink(dir);
+	dir->i_size -= sz_change;
+	dir_ui->ui_size = dir->i_size;
+	inode_set_mtime_to_ts(dir,
+			      inode_set_ctime_to_ts(dir, inode_get_ctime(inode)));
+	err = ubifs_jnl_update(c, dir, &nm, inode, 1, 0, 0);
+	if (err)
+		goto out_cancel;
+	unlock_2_inodes(dir, inode);
+
+	if (budgeted)
+		ubifs_release_budget(c, &req);
+	else {
+		/* We've deleted something - clean the "no space" flags */
+		c->bi.nospace = c->bi.nospace_rp = 0;
+		smp_wmb();
+	}
+	fscrypt_free_filename(&nm);
+	return 0;
+
+out_cancel:
+	dir->i_size += sz_change;
+	dir_ui->ui_size = dir->i_size;
+	inc_nlink(dir);
+	set_nlink(inode, 2);
+	unlock_2_inodes(dir, inode);
+	if (budgeted)
+		ubifs_release_budget(c, &req);
+out_fname:
+	fscrypt_free_filename(&nm);
+	return err;
+}
+
+static int ubifs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
+		       struct dentry *dentry, umode_t mode)
+{
+	struct inode *inode;
+	struct ubifs_inode *dir_ui = ubifs_inode(dir);
+	struct ubifs_info *c = dir->i_sb->s_fs_info;
+	int err, sz_change;
+	struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
+					.dirtied_ino = 1};
+	struct fscrypt_name nm;
+
+	/*
+	 * Budget request settings: new inode, new direntry and changing parent
+	 * directory inode.
+	 */
+
+	dbg_gen("dent '%pd', mode %#hx in dir ino %lu",
+		dentry, mode, dir->i_ino);
+
+	err = ubifs_budget_space(c, &req);
+	if (err)
+		return err;
+
+	err = ubifs_prepare_create(dir, dentry, &nm);
+	if (err)
+		goto out_budg;
+
+	sz_change = CALC_DENT_SIZE(fname_len(&nm));
+
+	inode = ubifs_new_inode(c, dir, S_IFDIR | mode, false);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto out_fname;
+	}
+
+	err = ubifs_init_security(dir, inode, &dentry->d_name);
+	if (err)
+		goto out_inode;
+
+	set_nlink(inode, 1);
+	mutex_lock(&dir_ui->ui_mutex);
+	insert_inode_hash(inode);
+	inc_nlink(inode);
+	inc_nlink(dir);
+	dir->i_size += sz_change;
+	dir_ui->ui_size = dir->i_size;
+	inode_set_mtime_to_ts(dir,
+			      inode_set_ctime_to_ts(dir, inode_get_ctime(inode)));
+	err = ubifs_jnl_update(c, dir, &nm, inode, 0, 0, 1);
+	if (err) {
+		ubifs_err(c, "cannot create directory, error %d", err);
+		goto out_cancel;
+	}
+	mutex_unlock(&dir_ui->ui_mutex);
+
+	ubifs_release_budget(c, &req);
+	d_instantiate(dentry, inode);
+	fscrypt_free_filename(&nm);
+	return 0;
+
+out_cancel:
+	dir->i_size -= sz_change;
+	dir_ui->ui_size = dir->i_size;
+	drop_nlink(dir);
+	mutex_unlock(&dir_ui->ui_mutex);
+	set_nlink(inode, 0);
+out_inode:
+	iput(inode);
+out_fname:
+	fscrypt_free_filename(&nm);
+out_budg:
+	ubifs_release_budget(c, &req);
+	return err;
+}
+
+static int ubifs_mknod(struct mnt_idmap *idmap, struct inode *dir,
+		       struct dentry *dentry, umode_t mode, dev_t rdev)
+{
+	struct inode *inode;
+	struct ubifs_inode *ui;
+	struct ubifs_inode *dir_ui = ubifs_inode(dir);
+	struct ubifs_info *c = dir->i_sb->s_fs_info;
+	union ubifs_dev_desc *dev = NULL;
+	int sz_change;
+	int err, devlen = 0;
+	struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
+					.dirtied_ino = 1 };
+	struct fscrypt_name nm;
+
+	/*
+	 * Budget request settings: new inode, new direntry and changing parent
+	 * directory inode.
+	 */
+
+	dbg_gen("dent '%pd' in dir ino %lu", dentry, dir->i_ino);
+
+	if (S_ISBLK(mode) || S_ISCHR(mode)) {
+		dev = kmalloc(sizeof(union ubifs_dev_desc), GFP_NOFS);
+		if (!dev)
+			return -ENOMEM;
+		devlen = ubifs_encode_dev(dev, rdev);
+	}
+
+	req.new_ino_d = ALIGN(devlen, 8);
+	err = ubifs_budget_space(c, &req);
+	if (err) {
+		kfree(dev);
+		return err;
+	}
+
+	err = ubifs_prepare_create(dir, dentry, &nm);
+	if (err) {
+		kfree(dev);
+		goto out_budg;
+	}
+
+	sz_change = CALC_DENT_SIZE(fname_len(&nm));
+
+	inode = ubifs_new_inode(c, dir, mode, false);
+	if (IS_ERR(inode)) {
+		kfree(dev);
+		err = PTR_ERR(inode);
+		goto out_fname;
+	}
+
+	err = ubifs_init_security(dir, inode, &dentry->d_name);
+	if (err) {
+		kfree(dev);
+		goto out_inode;
+	}
+
+	init_special_inode(inode, inode->i_mode, rdev);
+	inode->i_size = ubifs_inode(inode)->ui_size = devlen;
+	ui = ubifs_inode(inode);
+	ui->data = dev;
+	ui->data_len = devlen;
+	set_nlink(inode, 1);
+
+	mutex_lock(&dir_ui->ui_mutex);
+	dir->i_size += sz_change;
+	dir_ui->ui_size = dir->i_size;
+	inode_set_mtime_to_ts(dir,
+			      inode_set_ctime_to_ts(dir, inode_get_ctime(inode)));
+	err = ubifs_jnl_update(c, dir, &nm, inode, 0, 0, 1);
+	if (err)
+		goto out_cancel;
+	mutex_unlock(&dir_ui->ui_mutex);
+
+	ubifs_release_budget(c, &req);
+	insert_inode_hash(inode);
+	d_instantiate(dentry, inode);
+	fscrypt_free_filename(&nm);
+	return 0;
+
+out_cancel:
+	dir->i_size -= sz_change;
+	dir_ui->ui_size = dir->i_size;
+	mutex_unlock(&dir_ui->ui_mutex);
+	set_nlink(inode, 0);
+out_inode:
+	iput(inode);
+out_fname:
+	fscrypt_free_filename(&nm);
+out_budg:
+	ubifs_release_budget(c, &req);
+	return err;
+}
+
+static int ubifs_symlink(struct mnt_idmap *idmap, struct inode *dir,
+			 struct dentry *dentry, const char *symname)
+{
+	struct inode *inode;
+	struct ubifs_inode *ui;
+	struct ubifs_inode *dir_ui = ubifs_inode(dir);
+	struct ubifs_info *c = dir->i_sb->s_fs_info;
+	int err, sz_change, len = strlen(symname);
+	struct fscrypt_str disk_link;
+	struct ubifs_budget_req req = { .new_ino = 1, .new_dent = 1,
+					.dirtied_ino = 1 };
+	struct fscrypt_name nm;
+
+	dbg_gen("dent '%pd', target '%s' in dir ino %lu", dentry,
+		symname, dir->i_ino);
+
+	err = fscrypt_prepare_symlink(dir, symname, len, UBIFS_MAX_INO_DATA,
+				      &disk_link);
+	if (err)
+		return err;
+
+	/*
+	 * Budget request settings: new inode, new direntry and changing parent
+	 * directory inode.
+	 */
+	req.new_ino_d = ALIGN(disk_link.len - 1, 8);
+	err = ubifs_budget_space(c, &req);
+	if (err)
+		return err;
+
+	err = ubifs_prepare_create(dir, dentry, &nm);
+	if (err)
+		goto out_budg;
+
+	sz_change = CALC_DENT_SIZE(fname_len(&nm));
+
+	inode = ubifs_new_inode(c, dir, S_IFLNK | S_IRWXUGO, false);
+	if (IS_ERR(inode)) {
+		err = PTR_ERR(inode);
+		goto out_fname;
+	}
+
+	err = ubifs_init_security(dir, inode, &dentry->d_name);
+	if (err)
+		goto out_inode;
+
+	ui = ubifs_inode(inode);
+	ui->data = kmalloc(disk_link.len, GFP_NOFS);
+	if (!ui->data) {
+		err = -ENOMEM;
+		goto out_inode;
+	}
+
+	if (IS_ENCRYPTED(inode)) {
+		disk_link.name = ui->data; /* encrypt directly into ui->data */
+		err = fscrypt_encrypt_symlink(inode, symname, len, &disk_link);
+		if (err)
+			goto out_inode;
+	} else {
+		memcpy(ui->data, disk_link.name, disk_link.len);
+		inode->i_link = ui->data;
+	}
+
+	/*
+	 * The terminating zero byte is not written to the flash media and it
+	 * is put just to make later in-memory string processing simpler. Thus,
+	 * data length is @disk_link.len - 1, not @disk_link.len.
+	 */
+	ui->data_len = disk_link.len - 1;
+	inode->i_size = ubifs_inode(inode)->ui_size = disk_link.len - 1;
+	set_nlink(inode, 1);
+
+	mutex_lock(&dir_ui->ui_mutex);
+	dir->i_size += sz_change;
+	dir_ui->ui_size = dir->i_size;
+	inode_set_mtime_to_ts(dir,
+			      inode_set_ctime_to_ts(dir, inode_get_ctime(inode)));
+	err = ubifs_jnl_update(c, dir, &nm, inode, 0, 0, 1);
+	if (err)
+		goto out_cancel;
+	mutex_unlock(&dir_ui->ui_mutex);
+
+	insert_inode_hash(inode);
+	d_instantiate(dentry, inode);
+	err = 0;
+	goto out_fname;
+
+out_cancel:
+	dir->i_size -= sz_change;
+	dir_ui->ui_size = dir->i_size;
+	mutex_unlock(&dir_ui->ui_mutex);
+	set_nlink(inode, 0);
+out_inode:
+	/* Free inode->i_link before inode is marked as bad. */
+	fscrypt_free_inode(inode);
+	iput(inode);
+out_fname:
+	fscrypt_free_filename(&nm);
+out_budg:
+	ubifs_release_budget(c, &req);
+	return err;
+}
+
+/**
+ * lock_4_inodes - a wrapper for locking three UBIFS inodes.
+ * @inode1: first inode
+ * @inode2: second inode
+ * @inode3: third inode
+ * @inode4: fourth inode
+ *
+ * This function is used for 'ubifs_rename()' and @inode1 may be the same as
+ * @inode2 whereas @inode3 and @inode4 may be %NULL.
+ *
+ * We do not implement any tricks to guarantee strict lock ordering, because
+ * VFS has already done it for us on the @i_mutex. So this is just a simple
+ * wrapper function.
+ */
+static void lock_4_inodes(struct inode *inode1, struct inode *inode2,
+			  struct inode *inode3, struct inode *inode4)
+{
+	mutex_lock_nested(&ubifs_inode(inode1)->ui_mutex, WB_MUTEX_1);
+	if (inode2 != inode1)
+		mutex_lock_nested(&ubifs_inode(inode2)->ui_mutex, WB_MUTEX_2);
+	if (inode3)
+		mutex_lock_nested(&ubifs_inode(inode3)->ui_mutex, WB_MUTEX_3);
+	if (inode4)
+		mutex_lock_nested(&ubifs_inode(inode4)->ui_mutex, WB_MUTEX_4);
+}
+
+/**
+ * unlock_4_inodes - a wrapper for unlocking three UBIFS inodes for rename.
+ * @inode1: first inode
+ * @inode2: second inode
+ * @inode3: third inode
+ * @inode4: fourth inode
+ */
+static void unlock_4_inodes(struct inode *inode1, struct inode *inode2,
+			    struct inode *inode3, struct inode *inode4)
+{
+	if (inode4)
+		mutex_unlock(&ubifs_inode(inode4)->ui_mutex);
+	if (inode3)
+		mutex_unlock(&ubifs_inode(inode3)->ui_mutex);
+	if (inode1 != inode2)
+		mutex_unlock(&ubifs_inode(inode2)->ui_mutex);
+	mutex_unlock(&ubifs_inode(inode1)->ui_mutex);
+}
+
+static int do_rename(struct inode *old_dir, struct dentry *old_dentry,
+		     struct inode *new_dir, struct dentry *new_dentry,
+		     unsigned int flags)
+{
+	struct ubifs_info *c = old_dir->i_sb->s_fs_info;
+	struct inode *old_inode = d_inode(old_dentry);
+	struct inode *new_inode = d_inode(new_dentry);
+	struct inode *whiteout = NULL;
+	struct ubifs_inode *old_inode_ui = ubifs_inode(old_inode);
+	struct ubifs_inode *whiteout_ui = NULL;
+	int err, release, sync = 0, move = (new_dir != old_dir);
+	int is_dir = S_ISDIR(old_inode->i_mode);
+	int unlink = !!new_inode, new_sz, old_sz;
+	struct ubifs_budget_req req = { .new_dent = 1, .mod_dent = 1,
+					.dirtied_ino = 3 };
+	struct ubifs_budget_req ino_req = { .dirtied_ino = 1,
+			.dirtied_ino_d = ALIGN(old_inode_ui->data_len, 8) };
+	struct ubifs_budget_req wht_req;
+	unsigned int saved_nlink;
+	struct fscrypt_name old_nm, new_nm;
+
+	/*
+	 * Budget request settings:
+	 *   req: deletion direntry, new direntry, removing the old inode,
+	 *   and changing old and new parent directory inodes.
+	 *
+	 *   wht_req: new whiteout inode for RENAME_WHITEOUT.
+	 *
+	 *   ino_req: marks the target inode as dirty and does not write it.
+	 */
+
+	dbg_gen("dent '%pd' ino %lu in dir ino %lu to dent '%pd' in dir ino %lu flags 0x%x",
+		old_dentry, old_inode->i_ino, old_dir->i_ino,
+		new_dentry, new_dir->i_ino, flags);
+
+	if (unlink) {
+		ubifs_assert(c, inode_is_locked(new_inode));
+
+		/* Budget for old inode's data when its nlink > 1. */
+		req.dirtied_ino_d = ALIGN(ubifs_inode(new_inode)->data_len, 8);
+		err = ubifs_purge_xattrs(new_inode);
+		if (err)
+			return err;
+	}
+
+	if (unlink && is_dir) {
+		err = ubifs_check_dir_empty(new_inode);
+		if (err)
+			return err;
+	}
+
+	err = fscrypt_setup_filename(old_dir, &old_dentry->d_name, 0, &old_nm);
+	if (err)
+		return err;
+
+	err = fscrypt_setup_filename(new_dir, &new_dentry->d_name, 0, &new_nm);
+	if (err) {
+		fscrypt_free_filename(&old_nm);
+		return err;
+	}
+
+	new_sz = CALC_DENT_SIZE(fname_len(&new_nm));
+	old_sz = CALC_DENT_SIZE(fname_len(&old_nm));
+
+	err = ubifs_budget_space(c, &req);
+	if (err) {
+		fscrypt_free_filename(&old_nm);
+		fscrypt_free_filename(&new_nm);
+		return err;
+	}
+	err = ubifs_budget_space(c, &ino_req);
+	if (err) {
+		fscrypt_free_filename(&old_nm);
+		fscrypt_free_filename(&new_nm);
+		ubifs_release_budget(c, &req);
+		return err;
+	}
+
+	if (flags & RENAME_WHITEOUT) {
+		union ubifs_dev_desc *dev = NULL;
+
+		dev = kmalloc(sizeof(union ubifs_dev_desc), GFP_NOFS);
+		if (!dev) {
+			err = -ENOMEM;
+			goto out_release;
+		}
+
+		/*
+		 * The whiteout inode without dentry is pinned in memory,
+		 * umount won't happen during rename process because we
+		 * got parent dentry.
+		 */
+		whiteout = create_whiteout(old_dir, old_dentry);
+		if (IS_ERR(whiteout)) {
+			err = PTR_ERR(whiteout);
+			kfree(dev);
+			goto out_release;
+		}
+
+		whiteout_ui = ubifs_inode(whiteout);
+		whiteout_ui->data = dev;
+		whiteout_ui->data_len = ubifs_encode_dev(dev, MKDEV(0, 0));
+		ubifs_assert(c, !whiteout_ui->dirty);
+
+		memset(&wht_req, 0, sizeof(struct ubifs_budget_req));
+		wht_req.new_ino = 1;
+		wht_req.new_ino_d = ALIGN(whiteout_ui->data_len, 8);
+		/*
+		 * To avoid deadlock between space budget (holds ui_mutex and
+		 * waits wb work) and writeback work(waits ui_mutex), do space
+		 * budget before ubifs inodes locked.
+		 */
+		err = ubifs_budget_space(c, &wht_req);
+		if (err) {
+			iput(whiteout);
+			goto out_release;
+		}
+		set_nlink(whiteout, 1);
+
+		/* Add the old_dentry size to the old_dir size. */
+		old_sz -= CALC_DENT_SIZE(fname_len(&old_nm));
+	}
+
+	lock_4_inodes(old_dir, new_dir, new_inode, whiteout);
+
+	/*
+	 * Like most other Unix systems, set the @i_ctime for inodes on a
+	 * rename.
+	 */
+	simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry);
+
+	/* We must adjust parent link count when renaming directories */
+	if (is_dir) {
+		if (move) {
+			/*
+			 * @old_dir loses a link because we are moving
+			 * @old_inode to a different directory.
+			 */
+			drop_nlink(old_dir);
+			/*
+			 * @new_dir only gains a link if we are not also
+			 * overwriting an existing directory.
+			 */
+			if (!unlink)
+				inc_nlink(new_dir);
+		} else {
+			/*
+			 * @old_inode is not moving to a different directory,
+			 * but @old_dir still loses a link if we are
+			 * overwriting an existing directory.
+			 */
+			if (unlink)
+				drop_nlink(old_dir);
+		}
+	}
+
+	old_dir->i_size -= old_sz;
+	ubifs_inode(old_dir)->ui_size = old_dir->i_size;
+
+	/*
+	 * And finally, if we unlinked a direntry which happened to have the
+	 * same name as the moved direntry, we have to decrement @i_nlink of
+	 * the unlinked inode.
+	 */
+	if (unlink) {
+		/*
+		 * Directories cannot have hard-links, so if this is a
+		 * directory, just clear @i_nlink.
+		 */
+		saved_nlink = new_inode->i_nlink;
+		if (is_dir)
+			clear_nlink(new_inode);
+		else
+			drop_nlink(new_inode);
+	} else {
+		new_dir->i_size += new_sz;
+		ubifs_inode(new_dir)->ui_size = new_dir->i_size;
+	}
+
+	/*
+	 * Do not ask 'ubifs_jnl_rename()' to flush write-buffer if @old_inode
+	 * is dirty, because this will be done later on at the end of
+	 * 'ubifs_rename()'.
+	 */
+	if (IS_SYNC(old_inode)) {
+		sync = IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir);
+		if (unlink && IS_SYNC(new_inode))
+			sync = 1;
+		/*
+		 * S_SYNC flag of whiteout inherits from the old_dir, and we
+		 * have already checked the old dir inode. So there is no need
+		 * to check whiteout.
+		 */
+	}
+
+	err = ubifs_jnl_rename(c, old_dir, old_inode, &old_nm, new_dir,
+			       new_inode, &new_nm, whiteout, sync, !!whiteout);
+	if (err)
+		goto out_cancel;
+
+	unlock_4_inodes(old_dir, new_dir, new_inode, whiteout);
+	ubifs_release_budget(c, &req);
+
+	if (whiteout) {
+		ubifs_release_budget(c, &wht_req);
+		iput(whiteout);
+	}
+
+	mutex_lock(&old_inode_ui->ui_mutex);
+	release = old_inode_ui->dirty;
+	mark_inode_dirty_sync(old_inode);
+	mutex_unlock(&old_inode_ui->ui_mutex);
+
+	if (release)
+		ubifs_release_budget(c, &ino_req);
+	if (IS_SYNC(old_inode))
+		/*
+		 * Rename finished here. Although old inode cannot be updated
+		 * on flash, old ctime is not a big problem, don't return err
+		 * code to userspace.
+		 */
+		old_inode->i_sb->s_op->write_inode(old_inode, NULL);
+
+	fscrypt_free_filename(&old_nm);
+	fscrypt_free_filename(&new_nm);
+	return 0;
+
+out_cancel:
+	if (unlink) {
+		set_nlink(new_inode, saved_nlink);
+	} else {
+		new_dir->i_size -= new_sz;
+		ubifs_inode(new_dir)->ui_size = new_dir->i_size;
+	}
+	old_dir->i_size += old_sz;
+	ubifs_inode(old_dir)->ui_size = old_dir->i_size;
+	if (is_dir) {
+		if (move) {
+			inc_nlink(old_dir);
+			if (!unlink)
+				drop_nlink(new_dir);
+		} else {
+			if (unlink)
+				inc_nlink(old_dir);
+		}
+	}
+	unlock_4_inodes(old_dir, new_dir, new_inode, whiteout);
+	if (whiteout) {
+		ubifs_release_budget(c, &wht_req);
+		set_nlink(whiteout, 0);
+		iput(whiteout);
+	}
+out_release:
+	ubifs_release_budget(c, &ino_req);
+	ubifs_release_budget(c, &req);
+	fscrypt_free_filename(&old_nm);
+	fscrypt_free_filename(&new_nm);
+	return err;
+}
+
+static int ubifs_xrename(struct inode *old_dir, struct dentry *old_dentry,
+			struct inode *new_dir, struct dentry *new_dentry)
+{
+	struct ubifs_info *c = old_dir->i_sb->s_fs_info;
+	struct ubifs_budget_req req = { .new_dent = 1, .mod_dent = 1,
+				.dirtied_ino = 2 };
+	int sync = IS_DIRSYNC(old_dir) || IS_DIRSYNC(new_dir);
+	struct inode *fst_inode = d_inode(old_dentry);
+	struct inode *snd_inode = d_inode(new_dentry);
+	int err;
+	struct fscrypt_name fst_nm, snd_nm;
+
+	ubifs_assert(c, fst_inode && snd_inode);
+
+	/*
+	 * Budget request settings: changing two direntries, changing the two
+	 * parent directory inodes.
+	 */
+
+	dbg_gen("dent '%pd' ino %lu in dir ino %lu exchange dent '%pd' ino %lu in dir ino %lu",
+		old_dentry, fst_inode->i_ino, old_dir->i_ino,
+		new_dentry, snd_inode->i_ino, new_dir->i_ino);
+
+	err = fscrypt_setup_filename(old_dir, &old_dentry->d_name, 0, &fst_nm);
+	if (err)
+		return err;
+
+	err = fscrypt_setup_filename(new_dir, &new_dentry->d_name, 0, &snd_nm);
+	if (err) {
+		fscrypt_free_filename(&fst_nm);
+		return err;
+	}
+
+	err = ubifs_budget_space(c, &req);
+	if (err)
+		goto out;
+
+	lock_4_inodes(old_dir, new_dir, NULL, NULL);
+
+	simple_rename_timestamp(old_dir, old_dentry, new_dir, new_dentry);
+
+	if (old_dir != new_dir) {
+		if (S_ISDIR(fst_inode->i_mode) && !S_ISDIR(snd_inode->i_mode)) {
+			inc_nlink(new_dir);
+			drop_nlink(old_dir);
+		}
+		else if (!S_ISDIR(fst_inode->i_mode) && S_ISDIR(snd_inode->i_mode)) {
+			drop_nlink(new_dir);
+			inc_nlink(old_dir);
+		}
+	}
+
+	err = ubifs_jnl_xrename(c, old_dir, fst_inode, &fst_nm, new_dir,
+				snd_inode, &snd_nm, sync);
+
+	unlock_4_inodes(old_dir, new_dir, NULL, NULL);
+	ubifs_release_budget(c, &req);
+
+out:
+	fscrypt_free_filename(&fst_nm);
+	fscrypt_free_filename(&snd_nm);
+	return err;
+}
+
+static int ubifs_rename(struct mnt_idmap *idmap,
+			struct inode *old_dir, struct dentry *old_dentry,
+			struct inode *new_dir, struct dentry *new_dentry,
+			unsigned int flags)
+{
+	int err;
+	struct ubifs_info *c = old_dir->i_sb->s_fs_info;
+
+	if (flags & ~(RENAME_NOREPLACE | RENAME_WHITEOUT | RENAME_EXCHANGE))
+		return -EINVAL;
+
+	ubifs_assert(c, inode_is_locked(old_dir));
+	ubifs_assert(c, inode_is_locked(new_dir));
+
+	err = fscrypt_prepare_rename(old_dir, old_dentry, new_dir, new_dentry,
+				     flags);
+	if (err)
+		return err;
+
+	if (flags & RENAME_EXCHANGE)
+		return ubifs_xrename(old_dir, old_dentry, new_dir, new_dentry);
+
+	return do_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
+}
+
+int ubifs_getattr(struct mnt_idmap *idmap, const struct path *path,
+		  struct kstat *stat, u32 request_mask, unsigned int flags)
+{
+	loff_t size;
+	struct inode *inode = d_inode(path->dentry);
+	struct ubifs_inode *ui = ubifs_inode(inode);
+
+	mutex_lock(&ui->ui_mutex);
+
+	if (ui->flags & UBIFS_APPEND_FL)
+		stat->attributes |= STATX_ATTR_APPEND;
+	if (ui->flags & UBIFS_COMPR_FL)
+		stat->attributes |= STATX_ATTR_COMPRESSED;
+	if (ui->flags & UBIFS_CRYPT_FL)
+		stat->attributes |= STATX_ATTR_ENCRYPTED;
+	if (ui->flags & UBIFS_IMMUTABLE_FL)
+		stat->attributes |= STATX_ATTR_IMMUTABLE;
+
+	stat->attributes_mask |= (STATX_ATTR_APPEND |
+				STATX_ATTR_COMPRESSED |
+				STATX_ATTR_ENCRYPTED |
+				STATX_ATTR_IMMUTABLE);
+
+	generic_fillattr(&nop_mnt_idmap, request_mask, inode, stat);
+	stat->blksize = UBIFS_BLOCK_SIZE;
+	stat->size = ui->ui_size;
+
+	/*
+	 * Unfortunately, the 'stat()' system call was designed for block
+	 * device based file systems, and it is not appropriate for UBIFS,
+	 * because UBIFS does not have notion of "block". For example, it is
+	 * difficult to tell how many block a directory takes - it actually
+	 * takes less than 300 bytes, but we have to round it to block size,
+	 * which introduces large mistake. This makes utilities like 'du' to
+	 * report completely senseless numbers. This is the reason why UBIFS
+	 * goes the same way as JFFS2 - it reports zero blocks for everything
+	 * but regular files, which makes more sense than reporting completely
+	 * wrong sizes.
+	 */
+	if (S_ISREG(inode->i_mode)) {
+		size = ui->xattr_size;
+		size += stat->size;
+		size = ALIGN(size, UBIFS_BLOCK_SIZE);
+		/*
+		 * Note, user-space expects 512-byte blocks count irrespectively
+		 * of what was reported in @stat->size.
+		 */
+		stat->blocks = size >> 9;
+	} else
+		stat->blocks = 0;
+	mutex_unlock(&ui->ui_mutex);
+	return 0;
+}
+
+const struct inode_operations ubifs_dir_inode_operations = {
+	.lookup      = ubifs_lookup,
+	.create      = ubifs_create,
+	.link        = ubifs_link,
+	.symlink     = ubifs_symlink,
+	.unlink      = ubifs_unlink,
+	.mkdir       = ubifs_mkdir,
+	.rmdir       = ubifs_rmdir,
+	.mknod       = ubifs_mknod,
+	.rename      = ubifs_rename,
+	.setattr     = ubifs_setattr,
+	.getattr     = ubifs_getattr,
+	.listxattr   = ubifs_listxattr,
+	.update_time = ubifs_update_time,
+	.tmpfile     = ubifs_tmpfile,
+	.fileattr_get = ubifs_fileattr_get,
+	.fileattr_set = ubifs_fileattr_set,
+};
+
+const struct file_operations ubifs_dir_operations = {
+	.llseek         = generic_file_llseek,
+	.release        = ubifs_dir_release,
+	.read           = generic_read_dir,
+	.iterate_shared = ubifs_readdir,
+	.fsync          = ubifs_fsync,
+	.unlocked_ioctl = ubifs_ioctl,
+#ifdef CONFIG_COMPAT
+	.compat_ioctl   = ubifs_compat_ioctl,
+#endif
+};
diff --git a/ubifs-utils/libubifs/find.c b/ubifs-utils/libubifs/find.c
new file mode 100644
index 00000000..873e6e1c
--- /dev/null
+++ b/ubifs-utils/libubifs/find.c
@@ -0,0 +1,963 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ */
+
+/*
+ * This file contains functions for finding LEBs for various purposes e.g.
+ * garbage collection. In general, lprops category heaps and lists are used
+ * for fast access, falling back on scanning the LPT as a last resort.
+ */
+
+#include <linux/sort.h>
+#include "ubifs.h"
+
+/**
+ * struct scan_data - data provided to scan callback functions
+ * @min_space: minimum number of bytes for which to scan
+ * @pick_free: whether it is OK to scan for empty LEBs
+ * @lnum: LEB number found is returned here
+ * @exclude_index: whether to exclude index LEBs
+ */
+struct scan_data {
+	int min_space;
+	int pick_free;
+	int lnum;
+	int exclude_index;
+};
+
+/**
+ * valuable - determine whether LEB properties are valuable.
+ * @c: the UBIFS file-system description object
+ * @lprops: LEB properties
+ *
+ * This function return %1 if the LEB properties should be added to the LEB
+ * properties tree in memory. Otherwise %0 is returned.
+ */
+static int valuable(struct ubifs_info *c, const struct ubifs_lprops *lprops)
+{
+	int n, cat = lprops->flags & LPROPS_CAT_MASK;
+	struct ubifs_lpt_heap *heap;
+
+	switch (cat) {
+	case LPROPS_DIRTY:
+	case LPROPS_DIRTY_IDX:
+	case LPROPS_FREE:
+		heap = &c->lpt_heap[cat - 1];
+		if (heap->cnt < heap->max_cnt)
+			return 1;
+		if (lprops->free + lprops->dirty >= c->dark_wm)
+			return 1;
+		return 0;
+	case LPROPS_EMPTY:
+		n = c->lst.empty_lebs + c->freeable_cnt -
+		    c->lst.taken_empty_lebs;
+		if (n < c->lsave_cnt)
+			return 1;
+		return 0;
+	case LPROPS_FREEABLE:
+		return 1;
+	case LPROPS_FRDI_IDX:
+		return 1;
+	}
+	return 0;
+}
+
+/**
+ * scan_for_dirty_cb - dirty space scan callback.
+ * @c: the UBIFS file-system description object
+ * @lprops: LEB properties to scan
+ * @in_tree: whether the LEB properties are in main memory
+ * @data: information passed to and from the caller of the scan
+ *
+ * This function returns a code that indicates whether the scan should continue
+ * (%LPT_SCAN_CONTINUE), whether the LEB properties should be added to the tree
+ * in main memory (%LPT_SCAN_ADD), or whether the scan should stop
+ * (%LPT_SCAN_STOP).
+ */
+static int scan_for_dirty_cb(struct ubifs_info *c,
+			     const struct ubifs_lprops *lprops, int in_tree,
+			     struct scan_data *data)
+{
+	int ret = LPT_SCAN_CONTINUE;
+
+	/* Exclude LEBs that are currently in use */
+	if (lprops->flags & LPROPS_TAKEN)
+		return LPT_SCAN_CONTINUE;
+	/* Determine whether to add these LEB properties to the tree */
+	if (!in_tree && valuable(c, lprops))
+		ret |= LPT_SCAN_ADD;
+	/* Exclude LEBs with too little space */
+	if (lprops->free + lprops->dirty < data->min_space)
+		return ret;
+	/* If specified, exclude index LEBs */
+	if (data->exclude_index && lprops->flags & LPROPS_INDEX)
+		return ret;
+	/* If specified, exclude empty or freeable LEBs */
+	if (lprops->free + lprops->dirty == c->leb_size) {
+		if (!data->pick_free)
+			return ret;
+	/* Exclude LEBs with too little dirty space (unless it is empty) */
+	} else if (lprops->dirty < c->dead_wm)
+		return ret;
+	/* Finally we found space */
+	data->lnum = lprops->lnum;
+	return LPT_SCAN_ADD | LPT_SCAN_STOP;
+}
+
+/**
+ * scan_for_dirty - find a data LEB with free space.
+ * @c: the UBIFS file-system description object
+ * @min_space: minimum amount free plus dirty space the returned LEB has to
+ *             have
+ * @pick_free: if it is OK to return a free or freeable LEB
+ * @exclude_index: whether to exclude index LEBs
+ *
+ * This function returns a pointer to the LEB properties found or a negative
+ * error code.
+ */
+static const struct ubifs_lprops *scan_for_dirty(struct ubifs_info *c,
+						 int min_space, int pick_free,
+						 int exclude_index)
+{
+	const struct ubifs_lprops *lprops;
+	struct ubifs_lpt_heap *heap;
+	struct scan_data data;
+	int err, i;
+
+	/* There may be an LEB with enough dirty space on the free heap */
+	heap = &c->lpt_heap[LPROPS_FREE - 1];
+	for (i = 0; i < heap->cnt; i++) {
+		lprops = heap->arr[i];
+		if (lprops->free + lprops->dirty < min_space)
+			continue;
+		if (lprops->dirty < c->dead_wm)
+			continue;
+		return lprops;
+	}
+	/*
+	 * A LEB may have fallen off of the bottom of the dirty heap, and ended
+	 * up as uncategorized even though it has enough dirty space for us now,
+	 * so check the uncategorized list. N.B. neither empty nor freeable LEBs
+	 * can end up as uncategorized because they are kept on lists not
+	 * finite-sized heaps.
+	 */
+	list_for_each_entry(lprops, &c->uncat_list, list) {
+		if (lprops->flags & LPROPS_TAKEN)
+			continue;
+		if (lprops->free + lprops->dirty < min_space)
+			continue;
+		if (exclude_index && (lprops->flags & LPROPS_INDEX))
+			continue;
+		if (lprops->dirty < c->dead_wm)
+			continue;
+		return lprops;
+	}
+	/* We have looked everywhere in main memory, now scan the flash */
+	if (c->pnodes_have >= c->pnode_cnt)
+		/* All pnodes are in memory, so skip scan */
+		return ERR_PTR(-ENOSPC);
+	data.min_space = min_space;
+	data.pick_free = pick_free;
+	data.lnum = -1;
+	data.exclude_index = exclude_index;
+	err = ubifs_lpt_scan_nolock(c, -1, c->lscan_lnum,
+				    (ubifs_lpt_scan_callback)scan_for_dirty_cb,
+				    &data);
+	if (err)
+		return ERR_PTR(err);
+	ubifs_assert(c, data.lnum >= c->main_first && data.lnum < c->leb_cnt);
+	c->lscan_lnum = data.lnum;
+	lprops = ubifs_lpt_lookup_dirty(c, data.lnum);
+	if (IS_ERR(lprops))
+		return lprops;
+	ubifs_assert(c, lprops->lnum == data.lnum);
+	ubifs_assert(c, lprops->free + lprops->dirty >= min_space);
+	ubifs_assert(c, lprops->dirty >= c->dead_wm ||
+		     (pick_free &&
+		      lprops->free + lprops->dirty == c->leb_size));
+	ubifs_assert(c, !(lprops->flags & LPROPS_TAKEN));
+	ubifs_assert(c, !exclude_index || !(lprops->flags & LPROPS_INDEX));
+	return lprops;
+}
+
+/**
+ * ubifs_find_dirty_leb - find a dirty LEB for the Garbage Collector.
+ * @c: the UBIFS file-system description object
+ * @ret_lp: LEB properties are returned here on exit
+ * @min_space: minimum amount free plus dirty space the returned LEB has to
+ *             have
+ * @pick_free: controls whether it is OK to pick empty or index LEBs
+ *
+ * This function tries to find a dirty logical eraseblock which has at least
+ * @min_space free and dirty space. It prefers to take an LEB from the dirty or
+ * dirty index heap, and it falls-back to LPT scanning if the heaps are empty
+ * or do not have an LEB which satisfies the @min_space criteria.
+ *
+ * Note, LEBs which have less than dead watermark of free + dirty space are
+ * never picked by this function.
+ *
+ * The additional @pick_free argument controls if this function has to return a
+ * free or freeable LEB if one is present. For example, GC must to set it to %1,
+ * when called from the journal space reservation function, because the
+ * appearance of free space may coincide with the loss of enough dirty space
+ * for GC to succeed anyway.
+ *
+ * In contrast, if the Garbage Collector is called from budgeting, it should
+ * just make free space, not return LEBs which are already free or freeable.
+ *
+ * In addition @pick_free is set to %2 by the recovery process in order to
+ * recover gc_lnum in which case an index LEB must not be returned.
+ *
+ * This function returns zero and the LEB properties of found dirty LEB in case
+ * of success, %-ENOSPC if no dirty LEB was found and a negative error code in
+ * case of other failures. The returned LEB is marked as "taken".
+ */
+int ubifs_find_dirty_leb(struct ubifs_info *c, struct ubifs_lprops *ret_lp,
+			 int min_space, int pick_free)
+{
+	int err = 0, sum, exclude_index = pick_free == 2 ? 1 : 0;
+	const struct ubifs_lprops *lp = NULL, *idx_lp = NULL;
+	struct ubifs_lpt_heap *heap, *idx_heap;
+
+	ubifs_get_lprops(c);
+
+	if (pick_free) {
+		int lebs, rsvd_idx_lebs = 0;
+
+		spin_lock(&c->space_lock);
+		lebs = c->lst.empty_lebs + c->idx_gc_cnt;
+		lebs += c->freeable_cnt - c->lst.taken_empty_lebs;
+
+		/*
+		 * Note, the index may consume more LEBs than have been reserved
+		 * for it. It is OK because it might be consolidated by GC.
+		 * But if the index takes fewer LEBs than it is reserved for it,
+		 * this function must avoid picking those reserved LEBs.
+		 */
+		if (c->bi.min_idx_lebs >= c->lst.idx_lebs) {
+			rsvd_idx_lebs = c->bi.min_idx_lebs -  c->lst.idx_lebs;
+			exclude_index = 1;
+		}
+		spin_unlock(&c->space_lock);
+
+		/* Check if there are enough free LEBs for the index */
+		if (rsvd_idx_lebs < lebs) {
+			/* OK, try to find an empty LEB */
+			lp = ubifs_fast_find_empty(c);
+			if (lp)
+				goto found;
+
+			/* Or a freeable LEB */
+			lp = ubifs_fast_find_freeable(c);
+			if (lp)
+				goto found;
+		} else
+			/*
+			 * We cannot pick free/freeable LEBs in the below code.
+			 */
+			pick_free = 0;
+	} else {
+		spin_lock(&c->space_lock);
+		exclude_index = (c->bi.min_idx_lebs >= c->lst.idx_lebs);
+		spin_unlock(&c->space_lock);
+	}
+
+	/* Look on the dirty and dirty index heaps */
+	heap = &c->lpt_heap[LPROPS_DIRTY - 1];
+	idx_heap = &c->lpt_heap[LPROPS_DIRTY_IDX - 1];
+
+	if (idx_heap->cnt && !exclude_index) {
+		idx_lp = idx_heap->arr[0];
+		sum = idx_lp->free + idx_lp->dirty;
+		/*
+		 * Since we reserve thrice as much space for the index than it
+		 * actually takes, it does not make sense to pick indexing LEBs
+		 * with less than, say, half LEB of dirty space. May be half is
+		 * not the optimal boundary - this should be tested and
+		 * checked. This boundary should determine how much we use
+		 * in-the-gaps to consolidate the index comparing to how much
+		 * we use garbage collector to consolidate it. The "half"
+		 * criteria just feels to be fine.
+		 */
+		if (sum < min_space || sum < c->half_leb_size)
+			idx_lp = NULL;
+	}
+
+	if (heap->cnt) {
+		lp = heap->arr[0];
+		if (lp->dirty + lp->free < min_space)
+			lp = NULL;
+	}
+
+	/* Pick the LEB with most space */
+	if (idx_lp && lp) {
+		if (idx_lp->free + idx_lp->dirty >= lp->free + lp->dirty)
+			lp = idx_lp;
+	} else if (idx_lp && !lp)
+		lp = idx_lp;
+
+	if (lp) {
+		ubifs_assert(c, lp->free + lp->dirty >= c->dead_wm);
+		goto found;
+	}
+
+	/* Did not find a dirty LEB on the dirty heaps, have to scan */
+	dbg_find("scanning LPT for a dirty LEB");
+	lp = scan_for_dirty(c, min_space, pick_free, exclude_index);
+	if (IS_ERR(lp)) {
+		err = PTR_ERR(lp);
+		goto out;
+	}
+	ubifs_assert(c, lp->dirty >= c->dead_wm ||
+		     (pick_free && lp->free + lp->dirty == c->leb_size));
+
+found:
+	dbg_find("found LEB %d, free %d, dirty %d, flags %#x",
+		 lp->lnum, lp->free, lp->dirty, lp->flags);
+
+	lp = ubifs_change_lp(c, lp, LPROPS_NC, LPROPS_NC,
+			     lp->flags | LPROPS_TAKEN, 0);
+	if (IS_ERR(lp)) {
+		err = PTR_ERR(lp);
+		goto out;
+	}
+
+	memcpy(ret_lp, lp, sizeof(struct ubifs_lprops));
+
+out:
+	ubifs_release_lprops(c);
+	return err;
+}
+
+/**
+ * scan_for_free_cb - free space scan callback.
+ * @c: the UBIFS file-system description object
+ * @lprops: LEB properties to scan
+ * @in_tree: whether the LEB properties are in main memory
+ * @data: information passed to and from the caller of the scan
+ *
+ * This function returns a code that indicates whether the scan should continue
+ * (%LPT_SCAN_CONTINUE), whether the LEB properties should be added to the tree
+ * in main memory (%LPT_SCAN_ADD), or whether the scan should stop
+ * (%LPT_SCAN_STOP).
+ */
+static int scan_for_free_cb(struct ubifs_info *c,
+			    const struct ubifs_lprops *lprops, int in_tree,
+			    struct scan_data *data)
+{
+	int ret = LPT_SCAN_CONTINUE;
+
+	/* Exclude LEBs that are currently in use */
+	if (lprops->flags & LPROPS_TAKEN)
+		return LPT_SCAN_CONTINUE;
+	/* Determine whether to add these LEB properties to the tree */
+	if (!in_tree && valuable(c, lprops))
+		ret |= LPT_SCAN_ADD;
+	/* Exclude index LEBs */
+	if (lprops->flags & LPROPS_INDEX)
+		return ret;
+	/* Exclude LEBs with too little space */
+	if (lprops->free < data->min_space)
+		return ret;
+	/* If specified, exclude empty LEBs */
+	if (!data->pick_free && lprops->free == c->leb_size)
+		return ret;
+	/*
+	 * LEBs that have only free and dirty space must not be allocated
+	 * because they may have been unmapped already or they may have data
+	 * that is obsolete only because of nodes that are still sitting in a
+	 * wbuf.
+	 */
+	if (lprops->free + lprops->dirty == c->leb_size && lprops->dirty > 0)
+		return ret;
+	/* Finally we found space */
+	data->lnum = lprops->lnum;
+	return LPT_SCAN_ADD | LPT_SCAN_STOP;
+}
+
+/**
+ * do_find_free_space - find a data LEB with free space.
+ * @c: the UBIFS file-system description object
+ * @min_space: minimum amount of free space required
+ * @pick_free: whether it is OK to scan for empty LEBs
+ * @squeeze: whether to try to find space in a non-empty LEB first
+ *
+ * This function returns a pointer to the LEB properties found or a negative
+ * error code.
+ */
+static
+const struct ubifs_lprops *do_find_free_space(struct ubifs_info *c,
+					      int min_space, int pick_free,
+					      int squeeze)
+{
+	const struct ubifs_lprops *lprops;
+	struct ubifs_lpt_heap *heap;
+	struct scan_data data;
+	int err, i;
+
+	if (squeeze) {
+		lprops = ubifs_fast_find_free(c);
+		if (lprops && lprops->free >= min_space)
+			return lprops;
+	}
+	if (pick_free) {
+		lprops = ubifs_fast_find_empty(c);
+		if (lprops)
+			return lprops;
+	}
+	if (!squeeze) {
+		lprops = ubifs_fast_find_free(c);
+		if (lprops && lprops->free >= min_space)
+			return lprops;
+	}
+	/* There may be an LEB with enough free space on the dirty heap */
+	heap = &c->lpt_heap[LPROPS_DIRTY - 1];
+	for (i = 0; i < heap->cnt; i++) {
+		lprops = heap->arr[i];
+		if (lprops->free >= min_space)
+			return lprops;
+	}
+	/*
+	 * A LEB may have fallen off of the bottom of the free heap, and ended
+	 * up as uncategorized even though it has enough free space for us now,
+	 * so check the uncategorized list. N.B. neither empty nor freeable LEBs
+	 * can end up as uncategorized because they are kept on lists not
+	 * finite-sized heaps.
+	 */
+	list_for_each_entry(lprops, &c->uncat_list, list) {
+		if (lprops->flags & LPROPS_TAKEN)
+			continue;
+		if (lprops->flags & LPROPS_INDEX)
+			continue;
+		if (lprops->free >= min_space)
+			return lprops;
+	}
+	/* We have looked everywhere in main memory, now scan the flash */
+	if (c->pnodes_have >= c->pnode_cnt)
+		/* All pnodes are in memory, so skip scan */
+		return ERR_PTR(-ENOSPC);
+	data.min_space = min_space;
+	data.pick_free = pick_free;
+	data.lnum = -1;
+	err = ubifs_lpt_scan_nolock(c, -1, c->lscan_lnum,
+				    (ubifs_lpt_scan_callback)scan_for_free_cb,
+				    &data);
+	if (err)
+		return ERR_PTR(err);
+	ubifs_assert(c, data.lnum >= c->main_first && data.lnum < c->leb_cnt);
+	c->lscan_lnum = data.lnum;
+	lprops = ubifs_lpt_lookup_dirty(c, data.lnum);
+	if (IS_ERR(lprops))
+		return lprops;
+	ubifs_assert(c, lprops->lnum == data.lnum);
+	ubifs_assert(c, lprops->free >= min_space);
+	ubifs_assert(c, !(lprops->flags & LPROPS_TAKEN));
+	ubifs_assert(c, !(lprops->flags & LPROPS_INDEX));
+	return lprops;
+}
+
+/**
+ * ubifs_find_free_space - find a data LEB with free space.
+ * @c: the UBIFS file-system description object
+ * @min_space: minimum amount of required free space
+ * @offs: contains offset of where free space starts on exit
+ * @squeeze: whether to try to find space in a non-empty LEB first
+ *
+ * This function looks for an LEB with at least @min_space bytes of free space.
+ * It tries to find an empty LEB if possible. If no empty LEBs are available,
+ * this function searches for a non-empty data LEB. The returned LEB is marked
+ * as "taken".
+ *
+ * This function returns found LEB number in case of success, %-ENOSPC if it
+ * failed to find a LEB with @min_space bytes of free space and other a negative
+ * error codes in case of failure.
+ */
+int ubifs_find_free_space(struct ubifs_info *c, int min_space, int *offs,
+			  int squeeze)
+{
+	const struct ubifs_lprops *lprops;
+	int lebs, rsvd_idx_lebs, pick_free = 0, err, lnum, flags;
+
+	dbg_find("min_space %d", min_space);
+	ubifs_get_lprops(c);
+
+	/* Check if there are enough empty LEBs for commit */
+	spin_lock(&c->space_lock);
+	if (c->bi.min_idx_lebs > c->lst.idx_lebs)
+		rsvd_idx_lebs = c->bi.min_idx_lebs -  c->lst.idx_lebs;
+	else
+		rsvd_idx_lebs = 0;
+	lebs = c->lst.empty_lebs + c->freeable_cnt + c->idx_gc_cnt -
+	       c->lst.taken_empty_lebs;
+	if (rsvd_idx_lebs < lebs)
+		/*
+		 * OK to allocate an empty LEB, but we still don't want to go
+		 * looking for one if there aren't any.
+		 */
+		if (c->lst.empty_lebs - c->lst.taken_empty_lebs > 0) {
+			pick_free = 1;
+			/*
+			 * Because we release the space lock, we must account
+			 * for this allocation here. After the LEB properties
+			 * flags have been updated, we subtract one. Note, the
+			 * result of this is that lprops also decreases
+			 * @taken_empty_lebs in 'ubifs_change_lp()', so it is
+			 * off by one for a short period of time which may
+			 * introduce a small disturbance to budgeting
+			 * calculations, but this is harmless because at the
+			 * worst case this would make the budgeting subsystem
+			 * be more pessimistic than needed.
+			 *
+			 * Fundamentally, this is about serialization of the
+			 * budgeting and lprops subsystems. We could make the
+			 * @space_lock a mutex and avoid dropping it before
+			 * calling 'ubifs_change_lp()', but mutex is more
+			 * heavy-weight, and we want budgeting to be as fast as
+			 * possible.
+			 */
+			c->lst.taken_empty_lebs += 1;
+		}
+	spin_unlock(&c->space_lock);
+
+	lprops = do_find_free_space(c, min_space, pick_free, squeeze);
+	if (IS_ERR(lprops)) {
+		err = PTR_ERR(lprops);
+		goto out;
+	}
+
+	lnum = lprops->lnum;
+	flags = lprops->flags | LPROPS_TAKEN;
+
+	lprops = ubifs_change_lp(c, lprops, LPROPS_NC, LPROPS_NC, flags, 0);
+	if (IS_ERR(lprops)) {
+		err = PTR_ERR(lprops);
+		goto out;
+	}
+
+	if (pick_free) {
+		spin_lock(&c->space_lock);
+		c->lst.taken_empty_lebs -= 1;
+		spin_unlock(&c->space_lock);
+	}
+
+	*offs = c->leb_size - lprops->free;
+	ubifs_release_lprops(c);
+
+	if (*offs == 0) {
+		/*
+		 * Ensure that empty LEBs have been unmapped. They may not have
+		 * been, for example, because of an unclean unmount.  Also
+		 * LEBs that were freeable LEBs (free + dirty == leb_size) will
+		 * not have been unmapped.
+		 */
+		err = ubifs_leb_unmap(c, lnum);
+		if (err)
+			return err;
+	}
+
+	dbg_find("found LEB %d, free %d", lnum, c->leb_size - *offs);
+	ubifs_assert(c, *offs <= c->leb_size - min_space);
+	return lnum;
+
+out:
+	if (pick_free) {
+		spin_lock(&c->space_lock);
+		c->lst.taken_empty_lebs -= 1;
+		spin_unlock(&c->space_lock);
+	}
+	ubifs_release_lprops(c);
+	return err;
+}
+
+/**
+ * scan_for_idx_cb - callback used by the scan for a free LEB for the index.
+ * @c: the UBIFS file-system description object
+ * @lprops: LEB properties to scan
+ * @in_tree: whether the LEB properties are in main memory
+ * @data: information passed to and from the caller of the scan
+ *
+ * This function returns a code that indicates whether the scan should continue
+ * (%LPT_SCAN_CONTINUE), whether the LEB properties should be added to the tree
+ * in main memory (%LPT_SCAN_ADD), or whether the scan should stop
+ * (%LPT_SCAN_STOP).
+ */
+static int scan_for_idx_cb(struct ubifs_info *c,
+			   const struct ubifs_lprops *lprops, int in_tree,
+			   struct scan_data *data)
+{
+	int ret = LPT_SCAN_CONTINUE;
+
+	/* Exclude LEBs that are currently in use */
+	if (lprops->flags & LPROPS_TAKEN)
+		return LPT_SCAN_CONTINUE;
+	/* Determine whether to add these LEB properties to the tree */
+	if (!in_tree && valuable(c, lprops))
+		ret |= LPT_SCAN_ADD;
+	/* Exclude index LEBS */
+	if (lprops->flags & LPROPS_INDEX)
+		return ret;
+	/* Exclude LEBs that cannot be made empty */
+	if (lprops->free + lprops->dirty != c->leb_size)
+		return ret;
+	/*
+	 * We are allocating for the index so it is safe to allocate LEBs with
+	 * only free and dirty space, because write buffers are sync'd at commit
+	 * start.
+	 */
+	data->lnum = lprops->lnum;
+	return LPT_SCAN_ADD | LPT_SCAN_STOP;
+}
+
+/**
+ * scan_for_leb_for_idx - scan for a free LEB for the index.
+ * @c: the UBIFS file-system description object
+ */
+static const struct ubifs_lprops *scan_for_leb_for_idx(struct ubifs_info *c)
+{
+	const struct ubifs_lprops *lprops;
+	struct scan_data data;
+	int err;
+
+	data.lnum = -1;
+	err = ubifs_lpt_scan_nolock(c, -1, c->lscan_lnum,
+				    (ubifs_lpt_scan_callback)scan_for_idx_cb,
+				    &data);
+	if (err)
+		return ERR_PTR(err);
+	ubifs_assert(c, data.lnum >= c->main_first && data.lnum < c->leb_cnt);
+	c->lscan_lnum = data.lnum;
+	lprops = ubifs_lpt_lookup_dirty(c, data.lnum);
+	if (IS_ERR(lprops))
+		return lprops;
+	ubifs_assert(c, lprops->lnum == data.lnum);
+	ubifs_assert(c, lprops->free + lprops->dirty == c->leb_size);
+	ubifs_assert(c, !(lprops->flags & LPROPS_TAKEN));
+	ubifs_assert(c, !(lprops->flags & LPROPS_INDEX));
+	return lprops;
+}
+
+/**
+ * ubifs_find_free_leb_for_idx - find a free LEB for the index.
+ * @c: the UBIFS file-system description object
+ *
+ * This function looks for a free LEB and returns that LEB number. The returned
+ * LEB is marked as "taken", "index".
+ *
+ * Only empty LEBs are allocated. This is for two reasons. First, the commit
+ * calculates the number of LEBs to allocate based on the assumption that they
+ * will be empty. Secondly, free space at the end of an index LEB is not
+ * guaranteed to be empty because it may have been used by the in-the-gaps
+ * method prior to an unclean unmount.
+ *
+ * If no LEB is found %-ENOSPC is returned. For other failures another negative
+ * error code is returned.
+ */
+int ubifs_find_free_leb_for_idx(struct ubifs_info *c)
+{
+	const struct ubifs_lprops *lprops;
+	int lnum = -1, err, flags;
+
+	ubifs_get_lprops(c);
+
+	lprops = ubifs_fast_find_empty(c);
+	if (!lprops) {
+		lprops = ubifs_fast_find_freeable(c);
+		if (!lprops) {
+			/*
+			 * The first condition means the following: go scan the
+			 * LPT if there are uncategorized lprops, which means
+			 * there may be freeable LEBs there (UBIFS does not
+			 * store the information about freeable LEBs in the
+			 * master node).
+			 */
+			if (c->in_a_category_cnt != c->main_lebs ||
+			    c->lst.empty_lebs - c->lst.taken_empty_lebs > 0) {
+				ubifs_assert(c, c->freeable_cnt == 0);
+				lprops = scan_for_leb_for_idx(c);
+				if (IS_ERR(lprops)) {
+					err = PTR_ERR(lprops);
+					goto out;
+				}
+			}
+		}
+	}
+
+	if (!lprops) {
+		err = -ENOSPC;
+		goto out;
+	}
+
+	lnum = lprops->lnum;
+
+	dbg_find("found LEB %d, free %d, dirty %d, flags %#x",
+		 lnum, lprops->free, lprops->dirty, lprops->flags);
+
+	flags = lprops->flags | LPROPS_TAKEN | LPROPS_INDEX;
+	lprops = ubifs_change_lp(c, lprops, c->leb_size, 0, flags, 0);
+	if (IS_ERR(lprops)) {
+		err = PTR_ERR(lprops);
+		goto out;
+	}
+
+	ubifs_release_lprops(c);
+
+	/*
+	 * Ensure that empty LEBs have been unmapped. They may not have been,
+	 * for example, because of an unclean unmount. Also LEBs that were
+	 * freeable LEBs (free + dirty == leb_size) will not have been unmapped.
+	 */
+	err = ubifs_leb_unmap(c, lnum);
+	if (err) {
+		ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
+				    LPROPS_TAKEN | LPROPS_INDEX, 0);
+		return err;
+	}
+
+	return lnum;
+
+out:
+	ubifs_release_lprops(c);
+	return err;
+}
+
+static int cmp_dirty_idx(const struct ubifs_lprops **a,
+			 const struct ubifs_lprops **b)
+{
+	const struct ubifs_lprops *lpa = *a;
+	const struct ubifs_lprops *lpb = *b;
+
+	return lpa->dirty + lpa->free - lpb->dirty - lpb->free;
+}
+
+/**
+ * ubifs_save_dirty_idx_lnums - save an array of the most dirty index LEB nos.
+ * @c: the UBIFS file-system description object
+ *
+ * This function is called each commit to create an array of LEB numbers of
+ * dirty index LEBs sorted in order of dirty and free space.  This is used by
+ * the in-the-gaps method of TNC commit.
+ */
+int ubifs_save_dirty_idx_lnums(struct ubifs_info *c)
+{
+	int i;
+
+	ubifs_get_lprops(c);
+	/* Copy the LPROPS_DIRTY_IDX heap */
+	c->dirty_idx.cnt = c->lpt_heap[LPROPS_DIRTY_IDX - 1].cnt;
+	memcpy(c->dirty_idx.arr, c->lpt_heap[LPROPS_DIRTY_IDX - 1].arr,
+	       sizeof(void *) * c->dirty_idx.cnt);
+	/* Sort it so that the dirtiest is now at the end */
+	sort(c->dirty_idx.arr, c->dirty_idx.cnt, sizeof(void *),
+	     (int (*)(const void *, const void *))cmp_dirty_idx, NULL);
+	dbg_find("found %d dirty index LEBs", c->dirty_idx.cnt);
+	if (c->dirty_idx.cnt)
+		dbg_find("dirtiest index LEB is %d with dirty %d and free %d",
+			 c->dirty_idx.arr[c->dirty_idx.cnt - 1]->lnum,
+			 c->dirty_idx.arr[c->dirty_idx.cnt - 1]->dirty,
+			 c->dirty_idx.arr[c->dirty_idx.cnt - 1]->free);
+	/* Replace the lprops pointers with LEB numbers */
+	for (i = 0; i < c->dirty_idx.cnt; i++)
+		c->dirty_idx.arr[i] = (void *)(size_t)c->dirty_idx.arr[i]->lnum;
+	ubifs_release_lprops(c);
+	return 0;
+}
+
+/**
+ * scan_dirty_idx_cb - callback used by the scan for a dirty index LEB.
+ * @c: the UBIFS file-system description object
+ * @lprops: LEB properties to scan
+ * @in_tree: whether the LEB properties are in main memory
+ * @data: information passed to and from the caller of the scan
+ *
+ * This function returns a code that indicates whether the scan should continue
+ * (%LPT_SCAN_CONTINUE), whether the LEB properties should be added to the tree
+ * in main memory (%LPT_SCAN_ADD), or whether the scan should stop
+ * (%LPT_SCAN_STOP).
+ */
+static int scan_dirty_idx_cb(struct ubifs_info *c,
+			   const struct ubifs_lprops *lprops, int in_tree,
+			   struct scan_data *data)
+{
+	int ret = LPT_SCAN_CONTINUE;
+
+	/* Exclude LEBs that are currently in use */
+	if (lprops->flags & LPROPS_TAKEN)
+		return LPT_SCAN_CONTINUE;
+	/* Determine whether to add these LEB properties to the tree */
+	if (!in_tree && valuable(c, lprops))
+		ret |= LPT_SCAN_ADD;
+	/* Exclude non-index LEBs */
+	if (!(lprops->flags & LPROPS_INDEX))
+		return ret;
+	/* Exclude LEBs with too little space */
+	if (lprops->free + lprops->dirty < c->min_idx_node_sz)
+		return ret;
+	/* Finally we found space */
+	data->lnum = lprops->lnum;
+	return LPT_SCAN_ADD | LPT_SCAN_STOP;
+}
+
+/**
+ * find_dirty_idx_leb - find a dirty index LEB.
+ * @c: the UBIFS file-system description object
+ *
+ * This function returns LEB number upon success and a negative error code upon
+ * failure.  In particular, -ENOSPC is returned if a dirty index LEB is not
+ * found.
+ *
+ * Note that this function scans the entire LPT but it is called very rarely.
+ */
+static int find_dirty_idx_leb(struct ubifs_info *c)
+{
+	const struct ubifs_lprops *lprops;
+	struct ubifs_lpt_heap *heap;
+	struct scan_data data;
+	int err, i, ret;
+
+	/* Check all structures in memory first */
+	data.lnum = -1;
+	heap = &c->lpt_heap[LPROPS_DIRTY_IDX - 1];
+	for (i = 0; i < heap->cnt; i++) {
+		lprops = heap->arr[i];
+		ret = scan_dirty_idx_cb(c, lprops, 1, &data);
+		if (ret & LPT_SCAN_STOP)
+			goto found;
+	}
+	list_for_each_entry(lprops, &c->frdi_idx_list, list) {
+		ret = scan_dirty_idx_cb(c, lprops, 1, &data);
+		if (ret & LPT_SCAN_STOP)
+			goto found;
+	}
+	list_for_each_entry(lprops, &c->uncat_list, list) {
+		ret = scan_dirty_idx_cb(c, lprops, 1, &data);
+		if (ret & LPT_SCAN_STOP)
+			goto found;
+	}
+	if (c->pnodes_have >= c->pnode_cnt)
+		/* All pnodes are in memory, so skip scan */
+		return -ENOSPC;
+	err = ubifs_lpt_scan_nolock(c, -1, c->lscan_lnum,
+				    (ubifs_lpt_scan_callback)scan_dirty_idx_cb,
+				    &data);
+	if (err)
+		return err;
+found:
+	ubifs_assert(c, data.lnum >= c->main_first && data.lnum < c->leb_cnt);
+	c->lscan_lnum = data.lnum;
+	lprops = ubifs_lpt_lookup_dirty(c, data.lnum);
+	if (IS_ERR(lprops))
+		return PTR_ERR(lprops);
+	ubifs_assert(c, lprops->lnum == data.lnum);
+	ubifs_assert(c, lprops->free + lprops->dirty >= c->min_idx_node_sz);
+	ubifs_assert(c, !(lprops->flags & LPROPS_TAKEN));
+	ubifs_assert(c, (lprops->flags & LPROPS_INDEX));
+
+	dbg_find("found dirty LEB %d, free %d, dirty %d, flags %#x",
+		 lprops->lnum, lprops->free, lprops->dirty, lprops->flags);
+
+	lprops = ubifs_change_lp(c, lprops, LPROPS_NC, LPROPS_NC,
+				 lprops->flags | LPROPS_TAKEN, 0);
+	if (IS_ERR(lprops))
+		return PTR_ERR(lprops);
+
+	return lprops->lnum;
+}
+
+/**
+ * get_idx_gc_leb - try to get a LEB number from trivial GC.
+ * @c: the UBIFS file-system description object
+ */
+static int get_idx_gc_leb(struct ubifs_info *c)
+{
+	const struct ubifs_lprops *lp;
+	int err, lnum;
+
+	err = ubifs_get_idx_gc_leb(c);
+	if (err < 0)
+		return err;
+	lnum = err;
+	/*
+	 * The LEB was due to be unmapped after the commit but
+	 * it is needed now for this commit.
+	 */
+	lp = ubifs_lpt_lookup_dirty(c, lnum);
+	if (IS_ERR(lp))
+		return PTR_ERR(lp);
+	lp = ubifs_change_lp(c, lp, LPROPS_NC, LPROPS_NC,
+			     lp->flags | LPROPS_INDEX, -1);
+	if (IS_ERR(lp))
+		return PTR_ERR(lp);
+	dbg_find("LEB %d, dirty %d and free %d flags %#x",
+		 lp->lnum, lp->dirty, lp->free, lp->flags);
+	return lnum;
+}
+
+/**
+ * find_dirtiest_idx_leb - find dirtiest index LEB from dirtiest array.
+ * @c: the UBIFS file-system description object
+ */
+static int find_dirtiest_idx_leb(struct ubifs_info *c)
+{
+	const struct ubifs_lprops *lp;
+	int lnum;
+
+	while (1) {
+		if (!c->dirty_idx.cnt)
+			return -ENOSPC;
+		/* The lprops pointers were replaced by LEB numbers */
+		lnum = (size_t)c->dirty_idx.arr[--c->dirty_idx.cnt];
+		lp = ubifs_lpt_lookup(c, lnum);
+		if (IS_ERR(lp))
+			return PTR_ERR(lp);
+		if ((lp->flags & LPROPS_TAKEN) || !(lp->flags & LPROPS_INDEX))
+			continue;
+		lp = ubifs_change_lp(c, lp, LPROPS_NC, LPROPS_NC,
+				     lp->flags | LPROPS_TAKEN, 0);
+		if (IS_ERR(lp))
+			return PTR_ERR(lp);
+		break;
+	}
+	dbg_find("LEB %d, dirty %d and free %d flags %#x", lp->lnum, lp->dirty,
+		 lp->free, lp->flags);
+	ubifs_assert(c, lp->flags & LPROPS_TAKEN);
+	ubifs_assert(c, lp->flags & LPROPS_INDEX);
+	return lnum;
+}
+
+/**
+ * ubifs_find_dirty_idx_leb - try to find dirtiest index LEB as at last commit.
+ * @c: the UBIFS file-system description object
+ *
+ * This function attempts to find an untaken index LEB with the most free and
+ * dirty space that can be used without overwriting index nodes that were in the
+ * last index committed.
+ */
+int ubifs_find_dirty_idx_leb(struct ubifs_info *c)
+{
+	int err;
+
+	ubifs_get_lprops(c);
+
+	/*
+	 * We made an array of the dirtiest index LEB numbers as at the start of
+	 * last commit.  Try that array first.
+	 */
+	err = find_dirtiest_idx_leb(c);
+
+	/* Next try scanning the entire LPT */
+	if (err == -ENOSPC)
+		err = find_dirty_idx_leb(c);
+
+	/* Finally take any index LEBs awaiting trivial GC */
+	if (err == -ENOSPC)
+		err = get_idx_gc_leb(c);
+
+	ubifs_release_lprops(c);
+	return err;
+}
diff --git a/ubifs-utils/libubifs/gc.c b/ubifs-utils/libubifs/gc.c
new file mode 100644
index 00000000..3134d070
--- /dev/null
+++ b/ubifs-utils/libubifs/gc.c
@@ -0,0 +1,1017 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file implements garbage collection. The procedure for garbage collection
+ * is different depending on whether a LEB as an index LEB (contains index
+ * nodes) or not. For non-index LEBs, garbage collection finds a LEB which
+ * contains a lot of dirty space (obsolete nodes), and copies the non-obsolete
+ * nodes to the journal, at which point the garbage-collected LEB is free to be
+ * reused. For index LEBs, garbage collection marks the non-obsolete index nodes
+ * dirty in the TNC, and after the next commit, the garbage-collected LEB is
+ * to be reused. Garbage collection will cause the number of dirty index nodes
+ * to grow, however sufficient space is reserved for the index to ensure the
+ * commit will never run out of space.
+ *
+ * Notes about dead watermark. At current UBIFS implementation we assume that
+ * LEBs which have less than @c->dead_wm bytes of free + dirty space are full
+ * and not worth garbage-collecting. The dead watermark is one min. I/O unit
+ * size, or min. UBIFS node size, depending on what is greater. Indeed, UBIFS
+ * Garbage Collector has to synchronize the GC head's write buffer before
+ * returning, so this is about wasting one min. I/O unit. However, UBIFS GC can
+ * actually reclaim even very small pieces of dirty space by garbage collecting
+ * enough dirty LEBs, but we do not bother doing this at this implementation.
+ *
+ * Notes about dark watermark. The results of GC work depends on how big are
+ * the UBIFS nodes GC deals with. Large nodes make GC waste more space. Indeed,
+ * if GC move data from LEB A to LEB B and nodes in LEB A are large, GC would
+ * have to waste large pieces of free space at the end of LEB B, because nodes
+ * from LEB A would not fit. And the worst situation is when all nodes are of
+ * maximum size. So dark watermark is the amount of free + dirty space in LEB
+ * which are guaranteed to be reclaimable. If LEB has less space, the GC might
+ * be unable to reclaim it. So, LEBs with free + dirty greater than dark
+ * watermark are "good" LEBs from GC's point of view. The other LEBs are not so
+ * good, and GC takes extra care when moving them.
+ */
+
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/list_sort.h>
+#include "ubifs.h"
+
+/*
+ * GC may need to move more than one LEB to make progress. The below constants
+ * define "soft" and "hard" limits on the number of LEBs the garbage collector
+ * may move.
+ */
+#define SOFT_LEBS_LIMIT 4
+#define HARD_LEBS_LIMIT 32
+
+/**
+ * switch_gc_head - switch the garbage collection journal head.
+ * @c: UBIFS file-system description object
+ *
+ * This function switch the GC head to the next LEB which is reserved in
+ * @c->gc_lnum. Returns %0 in case of success, %-EAGAIN if commit is required,
+ * and other negative error code in case of failures.
+ */
+static int switch_gc_head(struct ubifs_info *c)
+{
+	int err, gc_lnum = c->gc_lnum;
+	struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
+
+	ubifs_assert(c, gc_lnum != -1);
+	dbg_gc("switch GC head from LEB %d:%d to LEB %d (waste %d bytes)",
+	       wbuf->lnum, wbuf->offs + wbuf->used, gc_lnum,
+	       c->leb_size - wbuf->offs - wbuf->used);
+
+	err = ubifs_wbuf_sync_nolock(wbuf);
+	if (err)
+		return err;
+
+	/*
+	 * The GC write-buffer was synchronized, we may safely unmap
+	 * 'c->gc_lnum'.
+	 */
+	err = ubifs_leb_unmap(c, gc_lnum);
+	if (err)
+		return err;
+
+	err = ubifs_add_bud_to_log(c, GCHD, gc_lnum, 0);
+	if (err)
+		return err;
+
+	c->gc_lnum = -1;
+	err = ubifs_wbuf_seek_nolock(wbuf, gc_lnum, 0);
+	return err;
+}
+
+/**
+ * data_nodes_cmp - compare 2 data nodes.
+ * @priv: UBIFS file-system description object
+ * @a: first data node
+ * @b: second data node
+ *
+ * This function compares data nodes @a and @b. Returns %1 if @a has greater
+ * inode or block number, and %-1 otherwise.
+ */
+static int data_nodes_cmp(void *priv, const struct list_head *a,
+			  const struct list_head *b)
+{
+	ino_t inuma, inumb;
+	struct ubifs_info *c = priv;
+	struct ubifs_scan_node *sa, *sb;
+
+	cond_resched();
+	if (a == b)
+		return 0;
+
+	sa = list_entry(a, struct ubifs_scan_node, list);
+	sb = list_entry(b, struct ubifs_scan_node, list);
+
+	ubifs_assert(c, key_type(c, &sa->key) == UBIFS_DATA_KEY);
+	ubifs_assert(c, key_type(c, &sb->key) == UBIFS_DATA_KEY);
+	ubifs_assert(c, sa->type == UBIFS_DATA_NODE);
+	ubifs_assert(c, sb->type == UBIFS_DATA_NODE);
+
+	inuma = key_inum(c, &sa->key);
+	inumb = key_inum(c, &sb->key);
+
+	if (inuma == inumb) {
+		unsigned int blka = key_block(c, &sa->key);
+		unsigned int blkb = key_block(c, &sb->key);
+
+		if (blka <= blkb)
+			return -1;
+	} else if (inuma <= inumb)
+		return -1;
+
+	return 1;
+}
+
+/*
+ * nondata_nodes_cmp - compare 2 non-data nodes.
+ * @priv: UBIFS file-system description object
+ * @a: first node
+ * @a: second node
+ *
+ * This function compares nodes @a and @b. It makes sure that inode nodes go
+ * first and sorted by length in descending order. Directory entry nodes go
+ * after inode nodes and are sorted in ascending hash valuer order.
+ */
+static int nondata_nodes_cmp(void *priv, const struct list_head *a,
+			     const struct list_head *b)
+{
+	ino_t inuma, inumb;
+	struct ubifs_info *c = priv;
+	struct ubifs_scan_node *sa, *sb;
+
+	cond_resched();
+	if (a == b)
+		return 0;
+
+	sa = list_entry(a, struct ubifs_scan_node, list);
+	sb = list_entry(b, struct ubifs_scan_node, list);
+
+	ubifs_assert(c, key_type(c, &sa->key) != UBIFS_DATA_KEY &&
+		     key_type(c, &sb->key) != UBIFS_DATA_KEY);
+	ubifs_assert(c, sa->type != UBIFS_DATA_NODE &&
+		     sb->type != UBIFS_DATA_NODE);
+
+	/* Inodes go before directory entries */
+	if (sa->type == UBIFS_INO_NODE) {
+		if (sb->type == UBIFS_INO_NODE)
+			return sb->len - sa->len;
+		return -1;
+	}
+	if (sb->type == UBIFS_INO_NODE)
+		return 1;
+
+	ubifs_assert(c, key_type(c, &sa->key) == UBIFS_DENT_KEY ||
+		     key_type(c, &sa->key) == UBIFS_XENT_KEY);
+	ubifs_assert(c, key_type(c, &sb->key) == UBIFS_DENT_KEY ||
+		     key_type(c, &sb->key) == UBIFS_XENT_KEY);
+	ubifs_assert(c, sa->type == UBIFS_DENT_NODE ||
+		     sa->type == UBIFS_XENT_NODE);
+	ubifs_assert(c, sb->type == UBIFS_DENT_NODE ||
+		     sb->type == UBIFS_XENT_NODE);
+
+	inuma = key_inum(c, &sa->key);
+	inumb = key_inum(c, &sb->key);
+
+	if (inuma == inumb) {
+		uint32_t hasha = key_hash(c, &sa->key);
+		uint32_t hashb = key_hash(c, &sb->key);
+
+		if (hasha <= hashb)
+			return -1;
+	} else if (inuma <= inumb)
+		return -1;
+
+	return 1;
+}
+
+/**
+ * sort_nodes - sort nodes for GC.
+ * @c: UBIFS file-system description object
+ * @sleb: describes nodes to sort and contains the result on exit
+ * @nondata: contains non-data nodes on exit
+ * @min: minimum node size is returned here
+ *
+ * This function sorts the list of inodes to garbage collect. First of all, it
+ * kills obsolete nodes and separates data and non-data nodes to the
+ * @sleb->nodes and @nondata lists correspondingly.
+ *
+ * Data nodes are then sorted in block number order - this is important for
+ * bulk-read; data nodes with lower inode number go before data nodes with
+ * higher inode number, and data nodes with lower block number go before data
+ * nodes with higher block number;
+ *
+ * Non-data nodes are sorted as follows.
+ *   o First go inode nodes - they are sorted in descending length order.
+ *   o Then go directory entry nodes - they are sorted in hash order, which
+ *     should supposedly optimize 'readdir()'. Direntry nodes with lower parent
+ *     inode number go before direntry nodes with higher parent inode number,
+ *     and direntry nodes with lower name hash values go before direntry nodes
+ *     with higher name hash values.
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+static int sort_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
+		      struct list_head *nondata, int *min)
+{
+	int err;
+	struct ubifs_scan_node *snod, *tmp;
+
+	*min = INT_MAX;
+
+	/* Separate data nodes and non-data nodes */
+	list_for_each_entry_safe(snod, tmp, &sleb->nodes, list) {
+		ubifs_assert(c, snod->type == UBIFS_INO_NODE  ||
+			     snod->type == UBIFS_DATA_NODE ||
+			     snod->type == UBIFS_DENT_NODE ||
+			     snod->type == UBIFS_XENT_NODE ||
+			     snod->type == UBIFS_TRUN_NODE ||
+			     snod->type == UBIFS_AUTH_NODE);
+
+		if (snod->type != UBIFS_INO_NODE  &&
+		    snod->type != UBIFS_DATA_NODE &&
+		    snod->type != UBIFS_DENT_NODE &&
+		    snod->type != UBIFS_XENT_NODE) {
+			/* Probably truncation node, zap it */
+			list_del(&snod->list);
+			kfree(snod);
+			continue;
+		}
+
+		ubifs_assert(c, key_type(c, &snod->key) == UBIFS_DATA_KEY ||
+			     key_type(c, &snod->key) == UBIFS_INO_KEY  ||
+			     key_type(c, &snod->key) == UBIFS_DENT_KEY ||
+			     key_type(c, &snod->key) == UBIFS_XENT_KEY);
+
+		err = ubifs_tnc_has_node(c, &snod->key, 0, sleb->lnum,
+					 snod->offs, 0);
+		if (err < 0)
+			return err;
+
+		if (!err) {
+			/* The node is obsolete, remove it from the list */
+			list_del(&snod->list);
+			kfree(snod);
+			continue;
+		}
+
+		if (snod->len < *min)
+			*min = snod->len;
+
+		if (key_type(c, &snod->key) != UBIFS_DATA_KEY)
+			list_move_tail(&snod->list, nondata);
+	}
+
+	/* Sort data and non-data nodes */
+	list_sort(c, &sleb->nodes, &data_nodes_cmp);
+	list_sort(c, nondata, &nondata_nodes_cmp);
+
+	err = dbg_check_data_nodes_order(c, &sleb->nodes);
+	if (err)
+		return err;
+	err = dbg_check_nondata_nodes_order(c, nondata);
+	if (err)
+		return err;
+	return 0;
+}
+
+/**
+ * move_node - move a node.
+ * @c: UBIFS file-system description object
+ * @sleb: describes the LEB to move nodes from
+ * @snod: the mode to move
+ * @wbuf: write-buffer to move node to
+ *
+ * This function moves node @snod to @wbuf, changes TNC correspondingly, and
+ * destroys @snod. Returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+static int move_node(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
+		     struct ubifs_scan_node *snod, struct ubifs_wbuf *wbuf)
+{
+	int err, new_lnum = wbuf->lnum, new_offs = wbuf->offs + wbuf->used;
+
+	cond_resched();
+	err = ubifs_wbuf_write_nolock(wbuf, snod->node, snod->len);
+	if (err)
+		return err;
+
+	err = ubifs_tnc_replace(c, &snod->key, sleb->lnum,
+				snod->offs, new_lnum, new_offs,
+				snod->len);
+	list_del(&snod->list);
+	kfree(snod);
+	return err;
+}
+
+/**
+ * move_nodes - move nodes.
+ * @c: UBIFS file-system description object
+ * @sleb: describes the LEB to move nodes from
+ *
+ * This function moves valid nodes from data LEB described by @sleb to the GC
+ * journal head. This function returns zero in case of success, %-EAGAIN if
+ * commit is required, and other negative error codes in case of other
+ * failures.
+ */
+static int move_nodes(struct ubifs_info *c, struct ubifs_scan_leb *sleb)
+{
+	int err, min;
+	LIST_HEAD(nondata);
+	struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
+
+	if (wbuf->lnum == -1) {
+		/*
+		 * The GC journal head is not set, because it is the first GC
+		 * invocation since mount.
+		 */
+		err = switch_gc_head(c);
+		if (err)
+			return err;
+	}
+
+	err = sort_nodes(c, sleb, &nondata, &min);
+	if (err)
+		goto out;
+
+	/* Write nodes to their new location. Use the first-fit strategy */
+	while (1) {
+		int avail, moved = 0;
+		struct ubifs_scan_node *snod, *tmp;
+
+		/* Move data nodes */
+		list_for_each_entry_safe(snod, tmp, &sleb->nodes, list) {
+			avail = c->leb_size - wbuf->offs - wbuf->used -
+					ubifs_auth_node_sz(c);
+			if  (snod->len > avail)
+				/*
+				 * Do not skip data nodes in order to optimize
+				 * bulk-read.
+				 */
+				break;
+
+			err = ubifs_shash_update(c, c->jheads[GCHD].log_hash,
+						 snod->node, snod->len);
+			if (err)
+				goto out;
+
+			err = move_node(c, sleb, snod, wbuf);
+			if (err)
+				goto out;
+			moved = 1;
+		}
+
+		/* Move non-data nodes */
+		list_for_each_entry_safe(snod, tmp, &nondata, list) {
+			avail = c->leb_size - wbuf->offs - wbuf->used -
+					ubifs_auth_node_sz(c);
+			if (avail < min)
+				break;
+
+			if  (snod->len > avail) {
+				/*
+				 * Keep going only if this is an inode with
+				 * some data. Otherwise stop and switch the GC
+				 * head. IOW, we assume that data-less inode
+				 * nodes and direntry nodes are roughly of the
+				 * same size.
+				 */
+				if (key_type(c, &snod->key) == UBIFS_DENT_KEY ||
+				    snod->len == UBIFS_INO_NODE_SZ)
+					break;
+				continue;
+			}
+
+			err = ubifs_shash_update(c, c->jheads[GCHD].log_hash,
+						 snod->node, snod->len);
+			if (err)
+				goto out;
+
+			err = move_node(c, sleb, snod, wbuf);
+			if (err)
+				goto out;
+			moved = 1;
+		}
+
+		if (ubifs_authenticated(c) && moved) {
+			struct ubifs_auth_node *auth;
+
+			auth = kmalloc(ubifs_auth_node_sz(c), GFP_NOFS);
+			if (!auth) {
+				err = -ENOMEM;
+				goto out;
+			}
+
+			err = ubifs_prepare_auth_node(c, auth,
+						c->jheads[GCHD].log_hash);
+			if (err) {
+				kfree(auth);
+				goto out;
+			}
+
+			err = ubifs_wbuf_write_nolock(wbuf, auth,
+						      ubifs_auth_node_sz(c));
+			if (err) {
+				kfree(auth);
+				goto out;
+			}
+
+			ubifs_add_dirt(c, wbuf->lnum, ubifs_auth_node_sz(c));
+		}
+
+		if (list_empty(&sleb->nodes) && list_empty(&nondata))
+			break;
+
+		/*
+		 * Waste the rest of the space in the LEB and switch to the
+		 * next LEB.
+		 */
+		err = switch_gc_head(c);
+		if (err)
+			goto out;
+	}
+
+	return 0;
+
+out:
+	list_splice_tail(&nondata, &sleb->nodes);
+	return err;
+}
+
+/**
+ * gc_sync_wbufs - sync write-buffers for GC.
+ * @c: UBIFS file-system description object
+ *
+ * We must guarantee that obsoleting nodes are on flash. Unfortunately they may
+ * be in a write-buffer instead. That is, a node could be written to a
+ * write-buffer, obsoleting another node in a LEB that is GC'd. If that LEB is
+ * erased before the write-buffer is sync'd and then there is an unclean
+ * unmount, then an existing node is lost. To avoid this, we sync all
+ * write-buffers.
+ *
+ * This function returns %0 on success or a negative error code on failure.
+ */
+static int gc_sync_wbufs(struct ubifs_info *c)
+{
+	int err, i;
+
+	for (i = 0; i < c->jhead_cnt; i++) {
+		if (i == GCHD)
+			continue;
+		err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
+		if (err)
+			return err;
+	}
+	return 0;
+}
+
+/**
+ * ubifs_garbage_collect_leb - garbage-collect a logical eraseblock.
+ * @c: UBIFS file-system description object
+ * @lp: describes the LEB to garbage collect
+ *
+ * This function garbage-collects an LEB and returns one of the @LEB_FREED,
+ * @LEB_RETAINED, etc positive codes in case of success, %-EAGAIN if commit is
+ * required, and other negative error codes in case of failures.
+ */
+int ubifs_garbage_collect_leb(struct ubifs_info *c, struct ubifs_lprops *lp)
+{
+	struct ubifs_scan_leb *sleb;
+	struct ubifs_scan_node *snod;
+	struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
+	int err = 0, lnum = lp->lnum;
+
+	ubifs_assert(c, c->gc_lnum != -1 || wbuf->offs + wbuf->used == 0 ||
+		     c->need_recovery);
+	ubifs_assert(c, c->gc_lnum != lnum);
+	ubifs_assert(c, wbuf->lnum != lnum);
+
+	if (lp->free + lp->dirty == c->leb_size) {
+		/* Special case - a free LEB  */
+		dbg_gc("LEB %d is free, return it", lp->lnum);
+		ubifs_assert(c, !(lp->flags & LPROPS_INDEX));
+
+		if (lp->free != c->leb_size) {
+			/*
+			 * Write buffers must be sync'd before unmapping
+			 * freeable LEBs, because one of them may contain data
+			 * which obsoletes something in 'lp->lnum'.
+			 */
+			err = gc_sync_wbufs(c);
+			if (err)
+				return err;
+			err = ubifs_change_one_lp(c, lp->lnum, c->leb_size,
+						  0, 0, 0, 0);
+			if (err)
+				return err;
+		}
+		err = ubifs_leb_unmap(c, lp->lnum);
+		if (err)
+			return err;
+
+		if (c->gc_lnum == -1) {
+			c->gc_lnum = lnum;
+			return LEB_RETAINED;
+		}
+
+		return LEB_FREED;
+	}
+
+	/*
+	 * We scan the entire LEB even though we only really need to scan up to
+	 * (c->leb_size - lp->free).
+	 */
+	sleb = ubifs_scan(c, lnum, 0, c->sbuf, 0);
+	if (IS_ERR(sleb))
+		return PTR_ERR(sleb);
+
+	ubifs_assert(c, !list_empty(&sleb->nodes));
+	snod = list_entry(sleb->nodes.next, struct ubifs_scan_node, list);
+
+	if (snod->type == UBIFS_IDX_NODE) {
+		struct ubifs_gced_idx_leb *idx_gc;
+
+		dbg_gc("indexing LEB %d (free %d, dirty %d)",
+		       lnum, lp->free, lp->dirty);
+		list_for_each_entry(snod, &sleb->nodes, list) {
+			struct ubifs_idx_node *idx = snod->node;
+			int level = le16_to_cpu(idx->level);
+
+			ubifs_assert(c, snod->type == UBIFS_IDX_NODE);
+			key_read(c, ubifs_idx_key(c, idx), &snod->key);
+			err = ubifs_dirty_idx_node(c, &snod->key, level, lnum,
+						   snod->offs);
+			if (err)
+				goto out;
+		}
+
+		idx_gc = kmalloc(sizeof(struct ubifs_gced_idx_leb), GFP_NOFS);
+		if (!idx_gc) {
+			err = -ENOMEM;
+			goto out;
+		}
+
+		idx_gc->lnum = lnum;
+		idx_gc->unmap = 0;
+		list_add(&idx_gc->list, &c->idx_gc);
+
+		/*
+		 * Don't release the LEB until after the next commit, because
+		 * it may contain data which is needed for recovery. So
+		 * although we freed this LEB, it will become usable only after
+		 * the commit.
+		 */
+		err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0,
+					  LPROPS_INDEX, 1);
+		if (err)
+			goto out;
+		err = LEB_FREED_IDX;
+	} else {
+		dbg_gc("data LEB %d (free %d, dirty %d)",
+		       lnum, lp->free, lp->dirty);
+
+		err = move_nodes(c, sleb);
+		if (err)
+			goto out_inc_seq;
+
+		err = gc_sync_wbufs(c);
+		if (err)
+			goto out_inc_seq;
+
+		err = ubifs_change_one_lp(c, lnum, c->leb_size, 0, 0, 0, 0);
+		if (err)
+			goto out_inc_seq;
+
+		/* Allow for races with TNC */
+		c->gced_lnum = lnum;
+		smp_wmb();
+		c->gc_seq += 1;
+		smp_wmb();
+
+		if (c->gc_lnum == -1) {
+			c->gc_lnum = lnum;
+			err = LEB_RETAINED;
+		} else {
+			err = ubifs_wbuf_sync_nolock(wbuf);
+			if (err)
+				goto out;
+
+			err = ubifs_leb_unmap(c, lnum);
+			if (err)
+				goto out;
+
+			err = LEB_FREED;
+		}
+	}
+
+out:
+	ubifs_scan_destroy(sleb);
+	return err;
+
+out_inc_seq:
+	/* We may have moved at least some nodes so allow for races with TNC */
+	c->gced_lnum = lnum;
+	smp_wmb();
+	c->gc_seq += 1;
+	smp_wmb();
+	goto out;
+}
+
+/**
+ * ubifs_garbage_collect - UBIFS garbage collector.
+ * @c: UBIFS file-system description object
+ * @anyway: do GC even if there are free LEBs
+ *
+ * This function does out-of-place garbage collection. The return codes are:
+ *   o positive LEB number if the LEB has been freed and may be used;
+ *   o %-EAGAIN if the caller has to run commit;
+ *   o %-ENOSPC if GC failed to make any progress;
+ *   o other negative error codes in case of other errors.
+ *
+ * Garbage collector writes data to the journal when GC'ing data LEBs, and just
+ * marking indexing nodes dirty when GC'ing indexing LEBs. Thus, at some point
+ * commit may be required. But commit cannot be run from inside GC, because the
+ * caller might be holding the commit lock, so %-EAGAIN is returned instead;
+ * And this error code means that the caller has to run commit, and re-run GC
+ * if there is still no free space.
+ *
+ * There are many reasons why this function may return %-EAGAIN:
+ * o the log is full and there is no space to write an LEB reference for
+ *   @c->gc_lnum;
+ * o the journal is too large and exceeds size limitations;
+ * o GC moved indexing LEBs, but they can be used only after the commit;
+ * o the shrinker fails to find clean znodes to free and requests the commit;
+ * o etc.
+ *
+ * Note, if the file-system is close to be full, this function may return
+ * %-EAGAIN infinitely, so the caller has to limit amount of re-invocations of
+ * the function. E.g., this happens if the limits on the journal size are too
+ * tough and GC writes too much to the journal before an LEB is freed. This
+ * might also mean that the journal is too large, and the TNC becomes to big,
+ * so that the shrinker is constantly called, finds not clean znodes to free,
+ * and requests commit. Well, this may also happen if the journal is all right,
+ * but another kernel process consumes too much memory. Anyway, infinite
+ * %-EAGAIN may happen, but in some extreme/misconfiguration cases.
+ */
+int ubifs_garbage_collect(struct ubifs_info *c, int anyway)
+{
+	int i, err, ret, min_space = c->dead_wm;
+	struct ubifs_lprops lp;
+	struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
+
+	ubifs_assert_cmt_locked(c);
+	ubifs_assert(c, !c->ro_media && !c->ro_mount);
+
+	if (ubifs_gc_should_commit(c))
+		return -EAGAIN;
+
+	mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
+
+	if (c->ro_error) {
+		ret = -EROFS;
+		goto out_unlock;
+	}
+
+	/* We expect the write-buffer to be empty on entry */
+	ubifs_assert(c, !wbuf->used);
+
+	for (i = 0; ; i++) {
+		int space_before, space_after;
+
+		/* Maybe continue after find and break before find */
+		lp.lnum = -1;
+
+		cond_resched();
+
+		/* Give the commit an opportunity to run */
+		if (ubifs_gc_should_commit(c)) {
+			ret = -EAGAIN;
+			break;
+		}
+
+		if (i > SOFT_LEBS_LIMIT && !list_empty(&c->idx_gc)) {
+			/*
+			 * We've done enough iterations. Indexing LEBs were
+			 * moved and will be available after the commit.
+			 */
+			dbg_gc("soft limit, some index LEBs GC'ed, -EAGAIN");
+			ubifs_commit_required(c);
+			ret = -EAGAIN;
+			break;
+		}
+
+		if (i > HARD_LEBS_LIMIT) {
+			/*
+			 * We've moved too many LEBs and have not made
+			 * progress, give up.
+			 */
+			dbg_gc("hard limit, -ENOSPC");
+			ret = -ENOSPC;
+			break;
+		}
+
+		/*
+		 * Empty and freeable LEBs can turn up while we waited for
+		 * the wbuf lock, or while we have been running GC. In that
+		 * case, we should just return one of those instead of
+		 * continuing to GC dirty LEBs. Hence we request
+		 * 'ubifs_find_dirty_leb()' to return an empty LEB if it can.
+		 */
+		ret = ubifs_find_dirty_leb(c, &lp, min_space, anyway ? 0 : 1);
+		if (ret) {
+			if (ret == -ENOSPC)
+				dbg_gc("no more dirty LEBs");
+			break;
+		}
+
+		dbg_gc("found LEB %d: free %d, dirty %d, sum %d (min. space %d)",
+		       lp.lnum, lp.free, lp.dirty, lp.free + lp.dirty,
+		       min_space);
+
+		space_before = c->leb_size - wbuf->offs - wbuf->used;
+		if (wbuf->lnum == -1)
+			space_before = 0;
+
+		ret = ubifs_garbage_collect_leb(c, &lp);
+		if (ret < 0) {
+			if (ret == -EAGAIN) {
+				/*
+				 * This is not error, so we have to return the
+				 * LEB to lprops. But if 'ubifs_return_leb()'
+				 * fails, its failure code is propagated to the
+				 * caller instead of the original '-EAGAIN'.
+				 */
+				err = ubifs_return_leb(c, lp.lnum);
+				if (err) {
+					ret = err;
+					/*
+					 * An LEB may always be "taken",
+					 * so setting ubifs to read-only,
+					 * and then executing sync wbuf will
+					 * return -EROFS and enter the "out"
+					 * error branch.
+					 */
+					ubifs_ro_mode(c, ret);
+				}
+				/*  Maybe double return LEB if goto out */
+				lp.lnum = -1;
+				break;
+			}
+			goto out;
+		}
+
+		if (ret == LEB_FREED) {
+			/* An LEB has been freed and is ready for use */
+			dbg_gc("LEB %d freed, return", lp.lnum);
+			ret = lp.lnum;
+			break;
+		}
+
+		if (ret == LEB_FREED_IDX) {
+			/*
+			 * This was an indexing LEB and it cannot be
+			 * immediately used. And instead of requesting the
+			 * commit straight away, we try to garbage collect some
+			 * more.
+			 */
+			dbg_gc("indexing LEB %d freed, continue", lp.lnum);
+			continue;
+		}
+
+		ubifs_assert(c, ret == LEB_RETAINED);
+		space_after = c->leb_size - wbuf->offs - wbuf->used;
+		dbg_gc("LEB %d retained, freed %d bytes", lp.lnum,
+		       space_after - space_before);
+
+		if (space_after > space_before) {
+			/* GC makes progress, keep working */
+			min_space >>= 1;
+			if (min_space < c->dead_wm)
+				min_space = c->dead_wm;
+			continue;
+		}
+
+		dbg_gc("did not make progress");
+
+		/*
+		 * GC moved an LEB bud have not done any progress. This means
+		 * that the previous GC head LEB contained too few free space
+		 * and the LEB which was GC'ed contained only large nodes which
+		 * did not fit that space.
+		 *
+		 * We can do 2 things:
+		 * 1. pick another LEB in a hope it'll contain a small node
+		 *    which will fit the space we have at the end of current GC
+		 *    head LEB, but there is no guarantee, so we try this out
+		 *    unless we have already been working for too long;
+		 * 2. request an LEB with more dirty space, which will force
+		 *    'ubifs_find_dirty_leb()' to start scanning the lprops
+		 *    table, instead of just picking one from the heap
+		 *    (previously it already picked the dirtiest LEB).
+		 */
+		if (i < SOFT_LEBS_LIMIT) {
+			dbg_gc("try again");
+			continue;
+		}
+
+		min_space <<= 1;
+		if (min_space > c->dark_wm)
+			min_space = c->dark_wm;
+		dbg_gc("set min. space to %d", min_space);
+	}
+
+	if (ret == -ENOSPC && !list_empty(&c->idx_gc)) {
+		dbg_gc("no space, some index LEBs GC'ed, -EAGAIN");
+		ubifs_commit_required(c);
+		ret = -EAGAIN;
+	}
+
+	err = ubifs_wbuf_sync_nolock(wbuf);
+	if (!err)
+		err = ubifs_leb_unmap(c, c->gc_lnum);
+	if (err) {
+		ret = err;
+		goto out;
+	}
+out_unlock:
+	mutex_unlock(&wbuf->io_mutex);
+	return ret;
+
+out:
+	ubifs_assert(c, ret < 0);
+	ubifs_assert(c, ret != -ENOSPC && ret != -EAGAIN);
+	ubifs_wbuf_sync_nolock(wbuf);
+	ubifs_ro_mode(c, ret);
+	mutex_unlock(&wbuf->io_mutex);
+	if (lp.lnum != -1)
+		ubifs_return_leb(c, lp.lnum);
+	return ret;
+}
+
+/**
+ * ubifs_gc_start_commit - garbage collection at start of commit.
+ * @c: UBIFS file-system description object
+ *
+ * If a LEB has only dirty and free space, then we may safely unmap it and make
+ * it free.  Note, we cannot do this with indexing LEBs because dirty space may
+ * correspond index nodes that are required for recovery.  In that case, the
+ * LEB cannot be unmapped until after the next commit.
+ *
+ * This function returns %0 upon success and a negative error code upon failure.
+ */
+int ubifs_gc_start_commit(struct ubifs_info *c)
+{
+	struct ubifs_gced_idx_leb *idx_gc;
+	const struct ubifs_lprops *lp;
+	int err = 0, flags;
+
+	ubifs_get_lprops(c);
+
+	/*
+	 * Unmap (non-index) freeable LEBs. Note that recovery requires that all
+	 * wbufs are sync'd before this, which is done in 'do_commit()'.
+	 */
+	while (1) {
+		lp = ubifs_fast_find_freeable(c);
+		if (!lp)
+			break;
+		ubifs_assert(c, !(lp->flags & LPROPS_TAKEN));
+		ubifs_assert(c, !(lp->flags & LPROPS_INDEX));
+		err = ubifs_leb_unmap(c, lp->lnum);
+		if (err)
+			goto out;
+		lp = ubifs_change_lp(c, lp, c->leb_size, 0, lp->flags, 0);
+		if (IS_ERR(lp)) {
+			err = PTR_ERR(lp);
+			goto out;
+		}
+		ubifs_assert(c, !(lp->flags & LPROPS_TAKEN));
+		ubifs_assert(c, !(lp->flags & LPROPS_INDEX));
+	}
+
+	/* Mark GC'd index LEBs OK to unmap after this commit finishes */
+	list_for_each_entry(idx_gc, &c->idx_gc, list)
+		idx_gc->unmap = 1;
+
+	/* Record index freeable LEBs for unmapping after commit */
+	while (1) {
+		lp = ubifs_fast_find_frdi_idx(c);
+		if (IS_ERR(lp)) {
+			err = PTR_ERR(lp);
+			goto out;
+		}
+		if (!lp)
+			break;
+		idx_gc = kmalloc(sizeof(struct ubifs_gced_idx_leb), GFP_NOFS);
+		if (!idx_gc) {
+			err = -ENOMEM;
+			goto out;
+		}
+		ubifs_assert(c, !(lp->flags & LPROPS_TAKEN));
+		ubifs_assert(c, lp->flags & LPROPS_INDEX);
+		/* Don't release the LEB until after the next commit */
+		flags = (lp->flags | LPROPS_TAKEN) ^ LPROPS_INDEX;
+		lp = ubifs_change_lp(c, lp, c->leb_size, 0, flags, 1);
+		if (IS_ERR(lp)) {
+			err = PTR_ERR(lp);
+			kfree(idx_gc);
+			goto out;
+		}
+		ubifs_assert(c, lp->flags & LPROPS_TAKEN);
+		ubifs_assert(c, !(lp->flags & LPROPS_INDEX));
+		idx_gc->lnum = lp->lnum;
+		idx_gc->unmap = 1;
+		list_add(&idx_gc->list, &c->idx_gc);
+	}
+out:
+	ubifs_release_lprops(c);
+	return err;
+}
+
+/**
+ * ubifs_gc_end_commit - garbage collection at end of commit.
+ * @c: UBIFS file-system description object
+ *
+ * This function completes out-of-place garbage collection of index LEBs.
+ */
+int ubifs_gc_end_commit(struct ubifs_info *c)
+{
+	struct ubifs_gced_idx_leb *idx_gc, *tmp;
+	struct ubifs_wbuf *wbuf;
+	int err = 0;
+
+	wbuf = &c->jheads[GCHD].wbuf;
+	mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
+	list_for_each_entry_safe(idx_gc, tmp, &c->idx_gc, list)
+		if (idx_gc->unmap) {
+			dbg_gc("LEB %d", idx_gc->lnum);
+			err = ubifs_leb_unmap(c, idx_gc->lnum);
+			if (err)
+				goto out;
+			err = ubifs_change_one_lp(c, idx_gc->lnum, LPROPS_NC,
+					  LPROPS_NC, 0, LPROPS_TAKEN, -1);
+			if (err)
+				goto out;
+			list_del(&idx_gc->list);
+			kfree(idx_gc);
+		}
+out:
+	mutex_unlock(&wbuf->io_mutex);
+	return err;
+}
+
+/**
+ * ubifs_destroy_idx_gc - destroy idx_gc list.
+ * @c: UBIFS file-system description object
+ *
+ * This function destroys the @c->idx_gc list. It is called when unmounting
+ * so locks are not needed. Returns zero in case of success and a negative
+ * error code in case of failure.
+ */
+void ubifs_destroy_idx_gc(struct ubifs_info *c)
+{
+	while (!list_empty(&c->idx_gc)) {
+		struct ubifs_gced_idx_leb *idx_gc;
+
+		idx_gc = list_entry(c->idx_gc.next, struct ubifs_gced_idx_leb,
+				    list);
+		c->idx_gc_cnt -= 1;
+		list_del(&idx_gc->list);
+		kfree(idx_gc);
+	}
+}
+
+/**
+ * ubifs_get_idx_gc_leb - get a LEB from GC'd index LEB list.
+ * @c: UBIFS file-system description object
+ *
+ * Called during start commit so locks are not needed.
+ */
+int ubifs_get_idx_gc_leb(struct ubifs_info *c)
+{
+	struct ubifs_gced_idx_leb *idx_gc;
+	int lnum;
+
+	if (list_empty(&c->idx_gc))
+		return -ENOSPC;
+	idx_gc = list_entry(c->idx_gc.next, struct ubifs_gced_idx_leb, list);
+	lnum = idx_gc->lnum;
+	/* c->idx_gc_cnt is updated by the caller when lprops are updated */
+	list_del(&idx_gc->list);
+	kfree(idx_gc);
+	return lnum;
+}
diff --git a/ubifs-utils/libubifs/io.c b/ubifs-utils/libubifs/io.c
new file mode 100644
index 00000000..01d8eb17
--- /dev/null
+++ b/ubifs-utils/libubifs/io.c
@@ -0,0 +1,1268 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ * Copyright (C) 2006, 2007 University of Szeged, Hungary
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ *          Zoltan Sogor
+ */
+
+/*
+ * This file implements UBIFS I/O subsystem which provides various I/O-related
+ * helper functions (reading/writing/checking/validating nodes) and implements
+ * write-buffering support. Write buffers help to save space which otherwise
+ * would have been wasted for padding to the nearest minimal I/O unit boundary.
+ * Instead, data first goes to the write-buffer and is flushed when the
+ * buffer is full or when it is not used for some time (by timer). This is
+ * similar to the mechanism is used by JFFS2.
+ *
+ * UBIFS distinguishes between minimum write size (@c->min_io_size) and maximum
+ * write size (@c->max_write_size). The latter is the maximum amount of bytes
+ * the underlying flash is able to program at a time, and writing in
+ * @c->max_write_size units should presumably be faster. Obviously,
+ * @c->min_io_size <= @c->max_write_size. Write-buffers are of
+ * @c->max_write_size bytes in size for maximum performance. However, when a
+ * write-buffer is flushed, only the portion of it (aligned to @c->min_io_size
+ * boundary) which contains data is written, not the whole write-buffer,
+ * because this is more space-efficient.
+ *
+ * This optimization adds few complications to the code. Indeed, on the one
+ * hand, we want to write in optimal @c->max_write_size bytes chunks, which
+ * also means aligning writes at the @c->max_write_size bytes offsets. On the
+ * other hand, we do not want to waste space when synchronizing the write
+ * buffer, so during synchronization we writes in smaller chunks. And this makes
+ * the next write offset to be not aligned to @c->max_write_size bytes. So the
+ * have to make sure that the write-buffer offset (@wbuf->offs) becomes aligned
+ * to @c->max_write_size bytes again. We do this by temporarily shrinking
+ * write-buffer size (@wbuf->size).
+ *
+ * Write-buffers are defined by 'struct ubifs_wbuf' objects and protected by
+ * mutexes defined inside these objects. Since sometimes upper-level code
+ * has to lock the write-buffer (e.g. journal space reservation code), many
+ * functions related to write-buffers have "nolock" suffix which means that the
+ * caller has to lock the write-buffer before calling this function.
+ *
+ * UBIFS stores nodes at 64 bit-aligned addresses. If the node length is not
+ * aligned, UBIFS starts the next node from the aligned address, and the padded
+ * bytes may contain any rubbish. In other words, UBIFS does not put padding
+ * bytes in those small gaps. Common headers of nodes store real node lengths,
+ * not aligned lengths. Indexing nodes also store real lengths in branches.
+ *
+ * UBIFS uses padding when it pads to the next min. I/O unit. In this case it
+ * uses padding nodes or padding bytes, if the padding node does not fit.
+ *
+ * All UBIFS nodes are protected by CRC checksums and UBIFS checks CRC when
+ * they are read from the flash media.
+ */
+
+#include <linux/crc32.h>
+#include <linux/slab.h>
+#include "ubifs.h"
+
+/**
+ * ubifs_ro_mode - switch UBIFS to read read-only mode.
+ * @c: UBIFS file-system description object
+ * @err: error code which is the reason of switching to R/O mode
+ */
+void ubifs_ro_mode(struct ubifs_info *c, int err)
+{
+	if (!c->ro_error) {
+		c->ro_error = 1;
+		c->no_chk_data_crc = 0;
+		c->vfs_sb->s_flags |= SB_RDONLY;
+		ubifs_warn(c, "switched to read-only mode, error %d", err);
+		dump_stack();
+	}
+}
+
+/*
+ * Below are simple wrappers over UBI I/O functions which include some
+ * additional checks and UBIFS debugging stuff. See corresponding UBI function
+ * for more information.
+ */
+
+int ubifs_leb_read(const struct ubifs_info *c, int lnum, void *buf, int offs,
+		   int len, int even_ebadmsg)
+{
+	int err;
+
+	err = ubi_read(c->ubi, lnum, buf, offs, len);
+	/*
+	 * In case of %-EBADMSG print the error message only if the
+	 * @even_ebadmsg is true.
+	 */
+	if (err && (err != -EBADMSG || even_ebadmsg)) {
+		ubifs_err(c, "reading %d bytes from LEB %d:%d failed, error %d",
+			  len, lnum, offs, err);
+		dump_stack();
+	}
+	return err;
+}
+
+int ubifs_leb_write(struct ubifs_info *c, int lnum, const void *buf, int offs,
+		    int len)
+{
+	int err;
+
+	ubifs_assert(c, !c->ro_media && !c->ro_mount);
+	if (c->ro_error)
+		return -EROFS;
+	if (!dbg_is_tst_rcvry(c))
+		err = ubi_leb_write(c->ubi, lnum, buf, offs, len);
+	else
+		err = dbg_leb_write(c, lnum, buf, offs, len);
+	if (err) {
+		ubifs_err(c, "writing %d bytes to LEB %d:%d failed, error %d",
+			  len, lnum, offs, err);
+		ubifs_ro_mode(c, err);
+		dump_stack();
+	}
+	return err;
+}
+
+int ubifs_leb_change(struct ubifs_info *c, int lnum, const void *buf, int len)
+{
+	int err;
+
+	ubifs_assert(c, !c->ro_media && !c->ro_mount);
+	if (c->ro_error)
+		return -EROFS;
+	if (!dbg_is_tst_rcvry(c))
+		err = ubi_leb_change(c->ubi, lnum, buf, len);
+	else
+		err = dbg_leb_change(c, lnum, buf, len);
+	if (err) {
+		ubifs_err(c, "changing %d bytes in LEB %d failed, error %d",
+			  len, lnum, err);
+		ubifs_ro_mode(c, err);
+		dump_stack();
+	}
+	return err;
+}
+
+int ubifs_leb_unmap(struct ubifs_info *c, int lnum)
+{
+	int err;
+
+	ubifs_assert(c, !c->ro_media && !c->ro_mount);
+	if (c->ro_error)
+		return -EROFS;
+	if (!dbg_is_tst_rcvry(c))
+		err = ubi_leb_unmap(c->ubi, lnum);
+	else
+		err = dbg_leb_unmap(c, lnum);
+	if (err) {
+		ubifs_err(c, "unmap LEB %d failed, error %d", lnum, err);
+		ubifs_ro_mode(c, err);
+		dump_stack();
+	}
+	return err;
+}
+
+int ubifs_leb_map(struct ubifs_info *c, int lnum)
+{
+	int err;
+
+	ubifs_assert(c, !c->ro_media && !c->ro_mount);
+	if (c->ro_error)
+		return -EROFS;
+	if (!dbg_is_tst_rcvry(c))
+		err = ubi_leb_map(c->ubi, lnum);
+	else
+		err = dbg_leb_map(c, lnum);
+	if (err) {
+		ubifs_err(c, "mapping LEB %d failed, error %d", lnum, err);
+		ubifs_ro_mode(c, err);
+		dump_stack();
+	}
+	return err;
+}
+
+int ubifs_is_mapped(const struct ubifs_info *c, int lnum)
+{
+	int err;
+
+	err = ubi_is_mapped(c->ubi, lnum);
+	if (err < 0) {
+		ubifs_err(c, "ubi_is_mapped failed for LEB %d, error %d",
+			  lnum, err);
+		dump_stack();
+	}
+	return err;
+}
+
+static void record_magic_error(struct ubifs_stats_info *stats)
+{
+	if (stats)
+		stats->magic_errors++;
+}
+
+static void record_node_error(struct ubifs_stats_info *stats)
+{
+	if (stats)
+		stats->node_errors++;
+}
+
+static void record_crc_error(struct ubifs_stats_info *stats)
+{
+	if (stats)
+		stats->crc_errors++;
+}
+
+/**
+ * ubifs_check_node - check node.
+ * @c: UBIFS file-system description object
+ * @buf: node to check
+ * @len: node length
+ * @lnum: logical eraseblock number
+ * @offs: offset within the logical eraseblock
+ * @quiet: print no messages
+ * @must_chk_crc: indicates whether to always check the CRC
+ *
+ * This function checks node magic number and CRC checksum. This function also
+ * validates node length to prevent UBIFS from becoming crazy when an attacker
+ * feeds it a file-system image with incorrect nodes. For example, too large
+ * node length in the common header could cause UBIFS to read memory outside of
+ * allocated buffer when checking the CRC checksum.
+ *
+ * This function may skip data nodes CRC checking if @c->no_chk_data_crc is
+ * true, which is controlled by corresponding UBIFS mount option. However, if
+ * @must_chk_crc is true, then @c->no_chk_data_crc is ignored and CRC is
+ * checked. Similarly, if @c->mounting or @c->remounting_rw is true (we are
+ * mounting or re-mounting to R/W mode), @c->no_chk_data_crc is ignored and CRC
+ * is checked. This is because during mounting or re-mounting from R/O mode to
+ * R/W mode we may read journal nodes (when replying the journal or doing the
+ * recovery) and the journal nodes may potentially be corrupted, so checking is
+ * required.
+ *
+ * This function returns zero in case of success and %-EUCLEAN in case of bad
+ * CRC or magic.
+ */
+int ubifs_check_node(const struct ubifs_info *c, const void *buf, int len,
+		     int lnum, int offs, int quiet, int must_chk_crc)
+{
+	int err = -EINVAL, type, node_len;
+	uint32_t crc, node_crc, magic;
+	const struct ubifs_ch *ch = buf;
+
+	ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
+	ubifs_assert(c, !(offs & 7) && offs < c->leb_size);
+
+	magic = le32_to_cpu(ch->magic);
+	if (magic != UBIFS_NODE_MAGIC) {
+		if (!quiet)
+			ubifs_err(c, "bad magic %#08x, expected %#08x",
+				  magic, UBIFS_NODE_MAGIC);
+		record_magic_error(c->stats);
+		err = -EUCLEAN;
+		goto out;
+	}
+
+	type = ch->node_type;
+	if (type < 0 || type >= UBIFS_NODE_TYPES_CNT) {
+		if (!quiet)
+			ubifs_err(c, "bad node type %d", type);
+		record_node_error(c->stats);
+		goto out;
+	}
+
+	node_len = le32_to_cpu(ch->len);
+	if (node_len + offs > c->leb_size)
+		goto out_len;
+
+	if (c->ranges[type].max_len == 0) {
+		if (node_len != c->ranges[type].len)
+			goto out_len;
+	} else if (node_len < c->ranges[type].min_len ||
+		   node_len > c->ranges[type].max_len)
+		goto out_len;
+
+	if (!must_chk_crc && type == UBIFS_DATA_NODE && !c->mounting &&
+	    !c->remounting_rw && c->no_chk_data_crc)
+		return 0;
+
+	crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
+	node_crc = le32_to_cpu(ch->crc);
+	if (crc != node_crc) {
+		if (!quiet)
+			ubifs_err(c, "bad CRC: calculated %#08x, read %#08x",
+				  crc, node_crc);
+		record_crc_error(c->stats);
+		err = -EUCLEAN;
+		goto out;
+	}
+
+	return 0;
+
+out_len:
+	if (!quiet)
+		ubifs_err(c, "bad node length %d", node_len);
+out:
+	if (!quiet) {
+		ubifs_err(c, "bad node at LEB %d:%d", lnum, offs);
+		ubifs_dump_node(c, buf, len);
+		dump_stack();
+	}
+	return err;
+}
+
+/**
+ * ubifs_pad - pad flash space.
+ * @c: UBIFS file-system description object
+ * @buf: buffer to put padding to
+ * @pad: how many bytes to pad
+ *
+ * The flash media obliges us to write only in chunks of %c->min_io_size and
+ * when we have to write less data we add padding node to the write-buffer and
+ * pad it to the next minimal I/O unit's boundary. Padding nodes help when the
+ * media is being scanned. If the amount of wasted space is not enough to fit a
+ * padding node which takes %UBIFS_PAD_NODE_SZ bytes, we write padding bytes
+ * pattern (%UBIFS_PADDING_BYTE).
+ *
+ * Padding nodes are also used to fill gaps when the "commit-in-gaps" method is
+ * used.
+ */
+void ubifs_pad(const struct ubifs_info *c, void *buf, int pad)
+{
+	uint32_t crc;
+
+	ubifs_assert(c, pad >= 0);
+
+	if (pad >= UBIFS_PAD_NODE_SZ) {
+		struct ubifs_ch *ch = buf;
+		struct ubifs_pad_node *pad_node = buf;
+
+		ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
+		ch->node_type = UBIFS_PAD_NODE;
+		ch->group_type = UBIFS_NO_NODE_GROUP;
+		ch->padding[0] = ch->padding[1] = 0;
+		ch->sqnum = 0;
+		ch->len = cpu_to_le32(UBIFS_PAD_NODE_SZ);
+		pad -= UBIFS_PAD_NODE_SZ;
+		pad_node->pad_len = cpu_to_le32(pad);
+		crc = crc32(UBIFS_CRC32_INIT, buf + 8, UBIFS_PAD_NODE_SZ - 8);
+		ch->crc = cpu_to_le32(crc);
+		memset(buf + UBIFS_PAD_NODE_SZ, 0, pad);
+	} else if (pad > 0)
+		/* Too little space, padding node won't fit */
+		memset(buf, UBIFS_PADDING_BYTE, pad);
+}
+
+/**
+ * next_sqnum - get next sequence number.
+ * @c: UBIFS file-system description object
+ */
+static unsigned long long next_sqnum(struct ubifs_info *c)
+{
+	unsigned long long sqnum;
+
+	spin_lock(&c->cnt_lock);
+	sqnum = ++c->max_sqnum;
+	spin_unlock(&c->cnt_lock);
+
+	if (unlikely(sqnum >= SQNUM_WARN_WATERMARK)) {
+		if (sqnum >= SQNUM_WATERMARK) {
+			ubifs_err(c, "sequence number overflow %llu, end of life",
+				  sqnum);
+			ubifs_ro_mode(c, -EINVAL);
+		}
+		ubifs_warn(c, "running out of sequence numbers, end of life soon");
+	}
+
+	return sqnum;
+}
+
+void ubifs_init_node(struct ubifs_info *c, void *node, int len, int pad)
+{
+	struct ubifs_ch *ch = node;
+	unsigned long long sqnum = next_sqnum(c);
+
+	ubifs_assert(c, len >= UBIFS_CH_SZ);
+
+	ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
+	ch->len = cpu_to_le32(len);
+	ch->group_type = UBIFS_NO_NODE_GROUP;
+	ch->sqnum = cpu_to_le64(sqnum);
+	ch->padding[0] = ch->padding[1] = 0;
+
+	if (pad) {
+		len = ALIGN(len, 8);
+		pad = ALIGN(len, c->min_io_size) - len;
+		ubifs_pad(c, node + len, pad);
+	}
+}
+
+void ubifs_crc_node(struct ubifs_info *c, void *node, int len)
+{
+	struct ubifs_ch *ch = node;
+	uint32_t crc;
+
+	crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);
+	ch->crc = cpu_to_le32(crc);
+}
+
+/**
+ * ubifs_prepare_node_hmac - prepare node to be written to flash.
+ * @c: UBIFS file-system description object
+ * @node: the node to pad
+ * @len: node length
+ * @hmac_offs: offset of the HMAC in the node
+ * @pad: if the buffer has to be padded
+ *
+ * This function prepares node at @node to be written to the media - it
+ * calculates node CRC, fills the common header, and adds proper padding up to
+ * the next minimum I/O unit if @pad is not zero. if @hmac_offs is positive then
+ * a HMAC is inserted into the node at the given offset.
+ *
+ * This function returns 0 for success or a negative error code otherwise.
+ */
+int ubifs_prepare_node_hmac(struct ubifs_info *c, void *node, int len,
+			    int hmac_offs, int pad)
+{
+	int err;
+
+	ubifs_init_node(c, node, len, pad);
+
+	if (hmac_offs > 0) {
+		err = ubifs_node_insert_hmac(c, node, len, hmac_offs);
+		if (err)
+			return err;
+	}
+
+	ubifs_crc_node(c, node, len);
+
+	return 0;
+}
+
+/**
+ * ubifs_prepare_node - prepare node to be written to flash.
+ * @c: UBIFS file-system description object
+ * @node: the node to pad
+ * @len: node length
+ * @pad: if the buffer has to be padded
+ *
+ * This function prepares node at @node to be written to the media - it
+ * calculates node CRC, fills the common header, and adds proper padding up to
+ * the next minimum I/O unit if @pad is not zero.
+ */
+void ubifs_prepare_node(struct ubifs_info *c, void *node, int len, int pad)
+{
+	/*
+	 * Deliberately ignore return value since this function can only fail
+	 * when a hmac offset is given.
+	 */
+	ubifs_prepare_node_hmac(c, node, len, 0, pad);
+}
+
+/**
+ * ubifs_prep_grp_node - prepare node of a group to be written to flash.
+ * @c: UBIFS file-system description object
+ * @node: the node to pad
+ * @len: node length
+ * @last: indicates the last node of the group
+ *
+ * This function prepares node at @node to be written to the media - it
+ * calculates node CRC and fills the common header.
+ */
+void ubifs_prep_grp_node(struct ubifs_info *c, void *node, int len, int last)
+{
+	uint32_t crc;
+	struct ubifs_ch *ch = node;
+	unsigned long long sqnum = next_sqnum(c);
+
+	ubifs_assert(c, len >= UBIFS_CH_SZ);
+
+	ch->magic = cpu_to_le32(UBIFS_NODE_MAGIC);
+	ch->len = cpu_to_le32(len);
+	if (last)
+		ch->group_type = UBIFS_LAST_OF_NODE_GROUP;
+	else
+		ch->group_type = UBIFS_IN_NODE_GROUP;
+	ch->sqnum = cpu_to_le64(sqnum);
+	ch->padding[0] = ch->padding[1] = 0;
+	crc = crc32(UBIFS_CRC32_INIT, node + 8, len - 8);
+	ch->crc = cpu_to_le32(crc);
+}
+
+/**
+ * wbuf_timer_callback_nolock - write-buffer timer callback function.
+ * @timer: timer data (write-buffer descriptor)
+ *
+ * This function is called when the write-buffer timer expires.
+ */
+static enum hrtimer_restart wbuf_timer_callback_nolock(struct hrtimer *timer)
+{
+	struct ubifs_wbuf *wbuf = container_of(timer, struct ubifs_wbuf, timer);
+
+	dbg_io("jhead %s", dbg_jhead(wbuf->jhead));
+	wbuf->need_sync = 1;
+	wbuf->c->need_wbuf_sync = 1;
+	ubifs_wake_up_bgt(wbuf->c);
+	return HRTIMER_NORESTART;
+}
+
+/**
+ * new_wbuf_timer_nolock - start new write-buffer timer.
+ * @c: UBIFS file-system description object
+ * @wbuf: write-buffer descriptor
+ */
+static void new_wbuf_timer_nolock(struct ubifs_info *c, struct ubifs_wbuf *wbuf)
+{
+	ktime_t softlimit = ms_to_ktime(dirty_writeback_interval * 10);
+	unsigned long long delta = dirty_writeback_interval;
+
+	/* centi to milli, milli to nano, then 10% */
+	delta *= 10ULL * NSEC_PER_MSEC / 10ULL;
+
+	ubifs_assert(c, !hrtimer_active(&wbuf->timer));
+	ubifs_assert(c, delta <= ULONG_MAX);
+
+	if (wbuf->no_timer)
+		return;
+	dbg_io("set timer for jhead %s, %llu-%llu millisecs",
+	       dbg_jhead(wbuf->jhead),
+	       div_u64(ktime_to_ns(softlimit), USEC_PER_SEC),
+	       div_u64(ktime_to_ns(softlimit) + delta, USEC_PER_SEC));
+	hrtimer_start_range_ns(&wbuf->timer, softlimit, delta,
+			       HRTIMER_MODE_REL);
+}
+
+/**
+ * cancel_wbuf_timer_nolock - cancel write-buffer timer.
+ * @wbuf: write-buffer descriptor
+ */
+static void cancel_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)
+{
+	if (wbuf->no_timer)
+		return;
+	wbuf->need_sync = 0;
+	hrtimer_cancel(&wbuf->timer);
+}
+
+/**
+ * ubifs_wbuf_sync_nolock - synchronize write-buffer.
+ * @wbuf: write-buffer to synchronize
+ *
+ * This function synchronizes write-buffer @buf and returns zero in case of
+ * success or a negative error code in case of failure.
+ *
+ * Note, although write-buffers are of @c->max_write_size, this function does
+ * not necessarily writes all @c->max_write_size bytes to the flash. Instead,
+ * if the write-buffer is only partially filled with data, only the used part
+ * of the write-buffer (aligned on @c->min_io_size boundary) is synchronized.
+ * This way we waste less space.
+ */
+int ubifs_wbuf_sync_nolock(struct ubifs_wbuf *wbuf)
+{
+	struct ubifs_info *c = wbuf->c;
+	int err, dirt, sync_len;
+
+	cancel_wbuf_timer_nolock(wbuf);
+	if (!wbuf->used || wbuf->lnum == -1)
+		/* Write-buffer is empty or not seeked */
+		return 0;
+
+	dbg_io("LEB %d:%d, %d bytes, jhead %s",
+	       wbuf->lnum, wbuf->offs, wbuf->used, dbg_jhead(wbuf->jhead));
+	ubifs_assert(c, !(wbuf->avail & 7));
+	ubifs_assert(c, wbuf->offs + wbuf->size <= c->leb_size);
+	ubifs_assert(c, wbuf->size >= c->min_io_size);
+	ubifs_assert(c, wbuf->size <= c->max_write_size);
+	ubifs_assert(c, wbuf->size % c->min_io_size == 0);
+	ubifs_assert(c, !c->ro_media && !c->ro_mount);
+	if (c->leb_size - wbuf->offs >= c->max_write_size)
+		ubifs_assert(c, !((wbuf->offs + wbuf->size) % c->max_write_size));
+
+	if (c->ro_error)
+		return -EROFS;
+
+	/*
+	 * Do not write whole write buffer but write only the minimum necessary
+	 * amount of min. I/O units.
+	 */
+	sync_len = ALIGN(wbuf->used, c->min_io_size);
+	dirt = sync_len - wbuf->used;
+	if (dirt)
+		ubifs_pad(c, wbuf->buf + wbuf->used, dirt);
+	err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs, sync_len);
+	if (err)
+		return err;
+
+	spin_lock(&wbuf->lock);
+	wbuf->offs += sync_len;
+	/*
+	 * Now @wbuf->offs is not necessarily aligned to @c->max_write_size.
+	 * But our goal is to optimize writes and make sure we write in
+	 * @c->max_write_size chunks and to @c->max_write_size-aligned offset.
+	 * Thus, if @wbuf->offs is not aligned to @c->max_write_size now, make
+	 * sure that @wbuf->offs + @wbuf->size is aligned to
+	 * @c->max_write_size. This way we make sure that after next
+	 * write-buffer flush we are again at the optimal offset (aligned to
+	 * @c->max_write_size).
+	 */
+	if (c->leb_size - wbuf->offs < c->max_write_size)
+		wbuf->size = c->leb_size - wbuf->offs;
+	else if (wbuf->offs & (c->max_write_size - 1))
+		wbuf->size = ALIGN(wbuf->offs, c->max_write_size) - wbuf->offs;
+	else
+		wbuf->size = c->max_write_size;
+	wbuf->avail = wbuf->size;
+	wbuf->used = 0;
+	wbuf->next_ino = 0;
+	spin_unlock(&wbuf->lock);
+
+	if (wbuf->sync_callback)
+		err = wbuf->sync_callback(c, wbuf->lnum,
+					  c->leb_size - wbuf->offs, dirt);
+	return err;
+}
+
+/**
+ * ubifs_wbuf_seek_nolock - seek write-buffer.
+ * @wbuf: write-buffer
+ * @lnum: logical eraseblock number to seek to
+ * @offs: logical eraseblock offset to seek to
+ *
+ * This function targets the write-buffer to logical eraseblock @lnum:@offs.
+ * The write-buffer has to be empty. Returns zero in case of success and a
+ * negative error code in case of failure.
+ */
+int ubifs_wbuf_seek_nolock(struct ubifs_wbuf *wbuf, int lnum, int offs)
+{
+	const struct ubifs_info *c = wbuf->c;
+
+	dbg_io("LEB %d:%d, jhead %s", lnum, offs, dbg_jhead(wbuf->jhead));
+	ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt);
+	ubifs_assert(c, offs >= 0 && offs <= c->leb_size);
+	ubifs_assert(c, offs % c->min_io_size == 0 && !(offs & 7));
+	ubifs_assert(c, lnum != wbuf->lnum);
+	ubifs_assert(c, wbuf->used == 0);
+
+	spin_lock(&wbuf->lock);
+	wbuf->lnum = lnum;
+	wbuf->offs = offs;
+	if (c->leb_size - wbuf->offs < c->max_write_size)
+		wbuf->size = c->leb_size - wbuf->offs;
+	else if (wbuf->offs & (c->max_write_size - 1))
+		wbuf->size = ALIGN(wbuf->offs, c->max_write_size) - wbuf->offs;
+	else
+		wbuf->size = c->max_write_size;
+	wbuf->avail = wbuf->size;
+	wbuf->used = 0;
+	spin_unlock(&wbuf->lock);
+
+	return 0;
+}
+
+/**
+ * ubifs_bg_wbufs_sync - synchronize write-buffers.
+ * @c: UBIFS file-system description object
+ *
+ * This function is called by background thread to synchronize write-buffers.
+ * Returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+int ubifs_bg_wbufs_sync(struct ubifs_info *c)
+{
+	int err, i;
+
+	ubifs_assert(c, !c->ro_media && !c->ro_mount);
+	if (!c->need_wbuf_sync)
+		return 0;
+	c->need_wbuf_sync = 0;
+
+	if (c->ro_error) {
+		err = -EROFS;
+		goto out_timers;
+	}
+
+	dbg_io("synchronize");
+	for (i = 0; i < c->jhead_cnt; i++) {
+		struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
+
+		cond_resched();
+
+		/*
+		 * If the mutex is locked then wbuf is being changed, so
+		 * synchronization is not necessary.
+		 */
+		if (mutex_is_locked(&wbuf->io_mutex))
+			continue;
+
+		mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
+		if (!wbuf->need_sync) {
+			mutex_unlock(&wbuf->io_mutex);
+			continue;
+		}
+
+		err = ubifs_wbuf_sync_nolock(wbuf);
+		mutex_unlock(&wbuf->io_mutex);
+		if (err) {
+			ubifs_err(c, "cannot sync write-buffer, error %d", err);
+			ubifs_ro_mode(c, err);
+			goto out_timers;
+		}
+	}
+
+	return 0;
+
+out_timers:
+	/* Cancel all timers to prevent repeated errors */
+	for (i = 0; i < c->jhead_cnt; i++) {
+		struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
+
+		mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
+		cancel_wbuf_timer_nolock(wbuf);
+		mutex_unlock(&wbuf->io_mutex);
+	}
+	return err;
+}
+
+/**
+ * ubifs_wbuf_write_nolock - write data to flash via write-buffer.
+ * @wbuf: write-buffer
+ * @buf: node to write
+ * @len: node length
+ *
+ * This function writes data to flash via write-buffer @wbuf. This means that
+ * the last piece of the node won't reach the flash media immediately if it
+ * does not take whole max. write unit (@c->max_write_size). Instead, the node
+ * will sit in RAM until the write-buffer is synchronized (e.g., by timer, or
+ * because more data are appended to the write-buffer).
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure. If the node cannot be written because there is no more
+ * space in this logical eraseblock, %-ENOSPC is returned.
+ */
+int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len)
+{
+	struct ubifs_info *c = wbuf->c;
+	int err, n, written = 0, aligned_len = ALIGN(len, 8);
+
+	dbg_io("%d bytes (%s) to jhead %s wbuf at LEB %d:%d", len,
+	       dbg_ntype(((struct ubifs_ch *)buf)->node_type),
+	       dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs + wbuf->used);
+	ubifs_assert(c, len > 0 && wbuf->lnum >= 0 && wbuf->lnum < c->leb_cnt);
+	ubifs_assert(c, wbuf->offs >= 0 && wbuf->offs % c->min_io_size == 0);
+	ubifs_assert(c, !(wbuf->offs & 7) && wbuf->offs <= c->leb_size);
+	ubifs_assert(c, wbuf->avail > 0 && wbuf->avail <= wbuf->size);
+	ubifs_assert(c, wbuf->size >= c->min_io_size);
+	ubifs_assert(c, wbuf->size <= c->max_write_size);
+	ubifs_assert(c, wbuf->size % c->min_io_size == 0);
+	ubifs_assert(c, mutex_is_locked(&wbuf->io_mutex));
+	ubifs_assert(c, !c->ro_media && !c->ro_mount);
+	ubifs_assert(c, !c->space_fixup);
+	if (c->leb_size - wbuf->offs >= c->max_write_size)
+		ubifs_assert(c, !((wbuf->offs + wbuf->size) % c->max_write_size));
+
+	if (c->leb_size - wbuf->offs - wbuf->used < aligned_len) {
+		err = -ENOSPC;
+		goto out;
+	}
+
+	cancel_wbuf_timer_nolock(wbuf);
+
+	if (c->ro_error)
+		return -EROFS;
+
+	if (aligned_len <= wbuf->avail) {
+		/*
+		 * The node is not very large and fits entirely within
+		 * write-buffer.
+		 */
+		memcpy(wbuf->buf + wbuf->used, buf, len);
+		if (aligned_len > len) {
+			ubifs_assert(c, aligned_len - len < 8);
+			ubifs_pad(c, wbuf->buf + wbuf->used + len, aligned_len - len);
+		}
+
+		if (aligned_len == wbuf->avail) {
+			dbg_io("flush jhead %s wbuf to LEB %d:%d",
+			       dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs);
+			err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf,
+					      wbuf->offs, wbuf->size);
+			if (err)
+				goto out;
+
+			spin_lock(&wbuf->lock);
+			wbuf->offs += wbuf->size;
+			if (c->leb_size - wbuf->offs >= c->max_write_size)
+				wbuf->size = c->max_write_size;
+			else
+				wbuf->size = c->leb_size - wbuf->offs;
+			wbuf->avail = wbuf->size;
+			wbuf->used = 0;
+			wbuf->next_ino = 0;
+			spin_unlock(&wbuf->lock);
+		} else {
+			spin_lock(&wbuf->lock);
+			wbuf->avail -= aligned_len;
+			wbuf->used += aligned_len;
+			spin_unlock(&wbuf->lock);
+		}
+
+		goto exit;
+	}
+
+	if (wbuf->used) {
+		/*
+		 * The node is large enough and does not fit entirely within
+		 * current available space. We have to fill and flush
+		 * write-buffer and switch to the next max. write unit.
+		 */
+		dbg_io("flush jhead %s wbuf to LEB %d:%d",
+		       dbg_jhead(wbuf->jhead), wbuf->lnum, wbuf->offs);
+		memcpy(wbuf->buf + wbuf->used, buf, wbuf->avail);
+		err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs,
+				      wbuf->size);
+		if (err)
+			goto out;
+
+		wbuf->offs += wbuf->size;
+		len -= wbuf->avail;
+		aligned_len -= wbuf->avail;
+		written += wbuf->avail;
+	} else if (wbuf->offs & (c->max_write_size - 1)) {
+		/*
+		 * The write-buffer offset is not aligned to
+		 * @c->max_write_size and @wbuf->size is less than
+		 * @c->max_write_size. Write @wbuf->size bytes to make sure the
+		 * following writes are done in optimal @c->max_write_size
+		 * chunks.
+		 */
+		dbg_io("write %d bytes to LEB %d:%d",
+		       wbuf->size, wbuf->lnum, wbuf->offs);
+		err = ubifs_leb_write(c, wbuf->lnum, buf, wbuf->offs,
+				      wbuf->size);
+		if (err)
+			goto out;
+
+		wbuf->offs += wbuf->size;
+		len -= wbuf->size;
+		aligned_len -= wbuf->size;
+		written += wbuf->size;
+	}
+
+	/*
+	 * The remaining data may take more whole max. write units, so write the
+	 * remains multiple to max. write unit size directly to the flash media.
+	 * We align node length to 8-byte boundary because we anyway flash wbuf
+	 * if the remaining space is less than 8 bytes.
+	 */
+	n = aligned_len >> c->max_write_shift;
+	if (n) {
+		int m = n - 1;
+
+		dbg_io("write %d bytes to LEB %d:%d", n, wbuf->lnum,
+		       wbuf->offs);
+
+		if (m) {
+			/* '(n-1)<<c->max_write_shift < len' is always true. */
+			m <<= c->max_write_shift;
+			err = ubifs_leb_write(c, wbuf->lnum, buf + written,
+					      wbuf->offs, m);
+			if (err)
+				goto out;
+			wbuf->offs += m;
+			aligned_len -= m;
+			len -= m;
+			written += m;
+		}
+
+		/*
+		 * The non-written len of buf may be less than 'n' because
+		 * parameter 'len' is not 8 bytes aligned, so here we read
+		 * min(len, n) bytes from buf.
+		 */
+		n = 1 << c->max_write_shift;
+		memcpy(wbuf->buf, buf + written, min(len, n));
+		if (n > len) {
+			ubifs_assert(c, n - len < 8);
+			ubifs_pad(c, wbuf->buf + len, n - len);
+		}
+
+		err = ubifs_leb_write(c, wbuf->lnum, wbuf->buf, wbuf->offs, n);
+		if (err)
+			goto out;
+		wbuf->offs += n;
+		aligned_len -= n;
+		len -= min(len, n);
+		written += n;
+	}
+
+	spin_lock(&wbuf->lock);
+	if (aligned_len) {
+		/*
+		 * And now we have what's left and what does not take whole
+		 * max. write unit, so write it to the write-buffer and we are
+		 * done.
+		 */
+		memcpy(wbuf->buf, buf + written, len);
+		if (aligned_len > len) {
+			ubifs_assert(c, aligned_len - len < 8);
+			ubifs_pad(c, wbuf->buf + len, aligned_len - len);
+		}
+	}
+
+	if (c->leb_size - wbuf->offs >= c->max_write_size)
+		wbuf->size = c->max_write_size;
+	else
+		wbuf->size = c->leb_size - wbuf->offs;
+	wbuf->avail = wbuf->size - aligned_len;
+	wbuf->used = aligned_len;
+	wbuf->next_ino = 0;
+	spin_unlock(&wbuf->lock);
+
+exit:
+	if (wbuf->sync_callback) {
+		int free = c->leb_size - wbuf->offs - wbuf->used;
+
+		err = wbuf->sync_callback(c, wbuf->lnum, free, 0);
+		if (err)
+			goto out;
+	}
+
+	if (wbuf->used)
+		new_wbuf_timer_nolock(c, wbuf);
+
+	return 0;
+
+out:
+	ubifs_err(c, "cannot write %d bytes to LEB %d:%d, error %d",
+		  len, wbuf->lnum, wbuf->offs, err);
+	ubifs_dump_node(c, buf, written + len);
+	dump_stack();
+	ubifs_dump_leb(c, wbuf->lnum);
+	return err;
+}
+
+/**
+ * ubifs_write_node_hmac - write node to the media.
+ * @c: UBIFS file-system description object
+ * @buf: the node to write
+ * @len: node length
+ * @lnum: logical eraseblock number
+ * @offs: offset within the logical eraseblock
+ * @hmac_offs: offset of the HMAC within the node
+ *
+ * This function automatically fills node magic number, assigns sequence
+ * number, and calculates node CRC checksum. The length of the @buf buffer has
+ * to be aligned to the minimal I/O unit size. This function automatically
+ * appends padding node and padding bytes if needed. Returns zero in case of
+ * success and a negative error code in case of failure.
+ */
+int ubifs_write_node_hmac(struct ubifs_info *c, void *buf, int len, int lnum,
+			  int offs, int hmac_offs)
+{
+	int err, buf_len = ALIGN(len, c->min_io_size);
+
+	dbg_io("LEB %d:%d, %s, length %d (aligned %d)",
+	       lnum, offs, dbg_ntype(((struct ubifs_ch *)buf)->node_type), len,
+	       buf_len);
+	ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
+	ubifs_assert(c, offs % c->min_io_size == 0 && offs < c->leb_size);
+	ubifs_assert(c, !c->ro_media && !c->ro_mount);
+	ubifs_assert(c, !c->space_fixup);
+
+	if (c->ro_error)
+		return -EROFS;
+
+	err = ubifs_prepare_node_hmac(c, buf, len, hmac_offs, 1);
+	if (err)
+		return err;
+
+	err = ubifs_leb_write(c, lnum, buf, offs, buf_len);
+	if (err)
+		ubifs_dump_node(c, buf, len);
+
+	return err;
+}
+
+/**
+ * ubifs_write_node - write node to the media.
+ * @c: UBIFS file-system description object
+ * @buf: the node to write
+ * @len: node length
+ * @lnum: logical eraseblock number
+ * @offs: offset within the logical eraseblock
+ *
+ * This function automatically fills node magic number, assigns sequence
+ * number, and calculates node CRC checksum. The length of the @buf buffer has
+ * to be aligned to the minimal I/O unit size. This function automatically
+ * appends padding node and padding bytes if needed. Returns zero in case of
+ * success and a negative error code in case of failure.
+ */
+int ubifs_write_node(struct ubifs_info *c, void *buf, int len, int lnum,
+		     int offs)
+{
+	return ubifs_write_node_hmac(c, buf, len, lnum, offs, -1);
+}
+
+/**
+ * ubifs_read_node_wbuf - read node from the media or write-buffer.
+ * @wbuf: wbuf to check for un-written data
+ * @buf: buffer to read to
+ * @type: node type
+ * @len: node length
+ * @lnum: logical eraseblock number
+ * @offs: offset within the logical eraseblock
+ *
+ * This function reads a node of known type and length, checks it and stores
+ * in @buf. If the node partially or fully sits in the write-buffer, this
+ * function takes data from the buffer, otherwise it reads the flash media.
+ * Returns zero in case of success, %-EUCLEAN if CRC mismatched and a negative
+ * error code in case of failure.
+ */
+int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
+			 int lnum, int offs)
+{
+	const struct ubifs_info *c = wbuf->c;
+	int err, rlen, overlap;
+	struct ubifs_ch *ch = buf;
+
+	dbg_io("LEB %d:%d, %s, length %d, jhead %s", lnum, offs,
+	       dbg_ntype(type), len, dbg_jhead(wbuf->jhead));
+	ubifs_assert(c, wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
+	ubifs_assert(c, !(offs & 7) && offs < c->leb_size);
+	ubifs_assert(c, type >= 0 && type < UBIFS_NODE_TYPES_CNT);
+
+	spin_lock(&wbuf->lock);
+	overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
+	if (!overlap) {
+		/* We may safely unlock the write-buffer and read the data */
+		spin_unlock(&wbuf->lock);
+		return ubifs_read_node(c, buf, type, len, lnum, offs);
+	}
+
+	/* Don't read under wbuf */
+	rlen = wbuf->offs - offs;
+	if (rlen < 0)
+		rlen = 0;
+
+	/* Copy the rest from the write-buffer */
+	memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
+	spin_unlock(&wbuf->lock);
+
+	if (rlen > 0) {
+		/* Read everything that goes before write-buffer */
+		err = ubifs_leb_read(c, lnum, buf, offs, rlen, 0);
+		if (err && err != -EBADMSG)
+			return err;
+	}
+
+	if (type != ch->node_type) {
+		ubifs_err(c, "bad node type (%d but expected %d)",
+			  ch->node_type, type);
+		goto out;
+	}
+
+	err = ubifs_check_node(c, buf, len, lnum, offs, 0, 0);
+	if (err) {
+		ubifs_err(c, "expected node type %d", type);
+		return err;
+	}
+
+	rlen = le32_to_cpu(ch->len);
+	if (rlen != len) {
+		ubifs_err(c, "bad node length %d, expected %d", rlen, len);
+		goto out;
+	}
+
+	return 0;
+
+out:
+	ubifs_err(c, "bad node at LEB %d:%d", lnum, offs);
+	ubifs_dump_node(c, buf, len);
+	dump_stack();
+	return -EINVAL;
+}
+
+/**
+ * ubifs_read_node - read node.
+ * @c: UBIFS file-system description object
+ * @buf: buffer to read to
+ * @type: node type
+ * @len: node length (not aligned)
+ * @lnum: logical eraseblock number
+ * @offs: offset within the logical eraseblock
+ *
+ * This function reads a node of known type and length, checks it and
+ * stores in @buf. Returns zero in case of success, %-EUCLEAN if CRC mismatched
+ * and a negative error code in case of failure.
+ */
+int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,
+		    int lnum, int offs)
+{
+	int err, l;
+	struct ubifs_ch *ch = buf;
+
+	dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
+	ubifs_assert(c, lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
+	ubifs_assert(c, len >= UBIFS_CH_SZ && offs + len <= c->leb_size);
+	ubifs_assert(c, !(offs & 7) && offs < c->leb_size);
+	ubifs_assert(c, type >= 0 && type < UBIFS_NODE_TYPES_CNT);
+
+	err = ubifs_leb_read(c, lnum, buf, offs, len, 0);
+	if (err && err != -EBADMSG)
+		return err;
+
+	if (type != ch->node_type) {
+		ubifs_errc(c, "bad node type (%d but expected %d)",
+			   ch->node_type, type);
+		goto out;
+	}
+
+	err = ubifs_check_node(c, buf, len, lnum, offs, 0, 0);
+	if (err) {
+		ubifs_errc(c, "expected node type %d", type);
+		return err;
+	}
+
+	l = le32_to_cpu(ch->len);
+	if (l != len) {
+		ubifs_errc(c, "bad node length %d, expected %d", l, len);
+		goto out;
+	}
+
+	return 0;
+
+out:
+	ubifs_errc(c, "bad node at LEB %d:%d, LEB mapping status %d", lnum,
+		   offs, ubi_is_mapped(c->ubi, lnum));
+	if (!c->probing) {
+		ubifs_dump_node(c, buf, len);
+		dump_stack();
+	}
+	return -EINVAL;
+}
+
+/**
+ * ubifs_wbuf_init - initialize write-buffer.
+ * @c: UBIFS file-system description object
+ * @wbuf: write-buffer to initialize
+ *
+ * This function initializes write-buffer. Returns zero in case of success
+ * %-ENOMEM in case of failure.
+ */
+int ubifs_wbuf_init(struct ubifs_info *c, struct ubifs_wbuf *wbuf)
+{
+	size_t size;
+
+	wbuf->buf = kmalloc(c->max_write_size, GFP_KERNEL);
+	if (!wbuf->buf)
+		return -ENOMEM;
+
+	size = (c->max_write_size / UBIFS_CH_SZ + 1) * sizeof(ino_t);
+	wbuf->inodes = kmalloc(size, GFP_KERNEL);
+	if (!wbuf->inodes) {
+		kfree(wbuf->buf);
+		wbuf->buf = NULL;
+		return -ENOMEM;
+	}
+
+	wbuf->used = 0;
+	wbuf->lnum = wbuf->offs = -1;
+	/*
+	 * If the LEB starts at the max. write size aligned address, then
+	 * write-buffer size has to be set to @c->max_write_size. Otherwise,
+	 * set it to something smaller so that it ends at the closest max.
+	 * write size boundary.
+	 */
+	size = c->max_write_size - (c->leb_start % c->max_write_size);
+	wbuf->avail = wbuf->size = size;
+	wbuf->sync_callback = NULL;
+	mutex_init(&wbuf->io_mutex);
+	spin_lock_init(&wbuf->lock);
+	wbuf->c = c;
+	wbuf->next_ino = 0;
+
+	hrtimer_init(&wbuf->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	wbuf->timer.function = wbuf_timer_callback_nolock;
+	return 0;
+}
+
+/**
+ * ubifs_wbuf_add_ino_nolock - add an inode number into the wbuf inode array.
+ * @wbuf: the write-buffer where to add
+ * @inum: the inode number
+ *
+ * This function adds an inode number to the inode array of the write-buffer.
+ */
+void ubifs_wbuf_add_ino_nolock(struct ubifs_wbuf *wbuf, ino_t inum)
+{
+	if (!wbuf->buf)
+		/* NOR flash or something similar */
+		return;
+
+	spin_lock(&wbuf->lock);
+	if (wbuf->used)
+		wbuf->inodes[wbuf->next_ino++] = inum;
+	spin_unlock(&wbuf->lock);
+}
+
+/**
+ * wbuf_has_ino - returns if the wbuf contains data from the inode.
+ * @wbuf: the write-buffer
+ * @inum: the inode number
+ *
+ * This function returns with %1 if the write-buffer contains some data from the
+ * given inode otherwise it returns with %0.
+ */
+static int wbuf_has_ino(struct ubifs_wbuf *wbuf, ino_t inum)
+{
+	int i, ret = 0;
+
+	spin_lock(&wbuf->lock);
+	for (i = 0; i < wbuf->next_ino; i++)
+		if (inum == wbuf->inodes[i]) {
+			ret = 1;
+			break;
+		}
+	spin_unlock(&wbuf->lock);
+
+	return ret;
+}
+
+/**
+ * ubifs_sync_wbufs_by_inode - synchronize write-buffers for an inode.
+ * @c: UBIFS file-system description object
+ * @inode: inode to synchronize
+ *
+ * This function synchronizes write-buffers which contain nodes belonging to
+ * @inode. Returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+int ubifs_sync_wbufs_by_inode(struct ubifs_info *c, struct inode *inode)
+{
+	int i, err = 0;
+
+	for (i = 0; i < c->jhead_cnt; i++) {
+		struct ubifs_wbuf *wbuf = &c->jheads[i].wbuf;
+
+		if (i == GCHD)
+			/*
+			 * GC head is special, do not look at it. Even if the
+			 * head contains something related to this inode, it is
+			 * a _copy_ of corresponding on-flash node which sits
+			 * somewhere else.
+			 */
+			continue;
+
+		if (!wbuf_has_ino(wbuf, inode->i_ino))
+			continue;
+
+		mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
+		if (wbuf_has_ino(wbuf, inode->i_ino))
+			err = ubifs_wbuf_sync_nolock(wbuf);
+		mutex_unlock(&wbuf->io_mutex);
+
+		if (err) {
+			ubifs_ro_mode(c, err);
+			return err;
+		}
+	}
+	return 0;
+}
diff --git a/ubifs-utils/libubifs/journal.c b/ubifs-utils/libubifs/journal.c
new file mode 100644
index 00000000..4590d616
--- /dev/null
+++ b/ubifs-utils/libubifs/journal.c
@@ -0,0 +1,1928 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ */
+
+/*
+ * This file implements UBIFS journal.
+ *
+ * The journal consists of 2 parts - the log and bud LEBs. The log has fixed
+ * length and position, while a bud logical eraseblock is any LEB in the main
+ * area. Buds contain file system data - data nodes, inode nodes, etc. The log
+ * contains only references to buds and some other stuff like commit
+ * start node. The idea is that when we commit the journal, we do
+ * not copy the data, the buds just become indexed. Since after the commit the
+ * nodes in bud eraseblocks become leaf nodes of the file system index tree, we
+ * use term "bud". Analogy is obvious, bud eraseblocks contain nodes which will
+ * become leafs in the future.
+ *
+ * The journal is multi-headed because we want to write data to the journal as
+ * optimally as possible. It is nice to have nodes belonging to the same inode
+ * in one LEB, so we may write data owned by different inodes to different
+ * journal heads, although at present only one data head is used.
+ *
+ * For recovery reasons, the base head contains all inode nodes, all directory
+ * entry nodes and all truncate nodes. This means that the other heads contain
+ * only data nodes.
+ *
+ * Bud LEBs may be half-indexed. For example, if the bud was not full at the
+ * time of commit, the bud is retained to continue to be used in the journal,
+ * even though the "front" of the LEB is now indexed. In that case, the log
+ * reference contains the offset where the bud starts for the purposes of the
+ * journal.
+ *
+ * The journal size has to be limited, because the larger is the journal, the
+ * longer it takes to mount UBIFS (scanning the journal) and the more memory it
+ * takes (indexing in the TNC).
+ *
+ * All the journal write operations like 'ubifs_jnl_update()' here, which write
+ * multiple UBIFS nodes to the journal at one go, are atomic with respect to
+ * unclean reboots. Should the unclean reboot happen, the recovery code drops
+ * all the nodes.
+ */
+
+#include "ubifs.h"
+
+/**
+ * zero_ino_node_unused - zero out unused fields of an on-flash inode node.
+ * @ino: the inode to zero out
+ */
+static inline void zero_ino_node_unused(struct ubifs_ino_node *ino)
+{
+	memset(ino->padding1, 0, 4);
+	memset(ino->padding2, 0, 26);
+}
+
+/**
+ * zero_dent_node_unused - zero out unused fields of an on-flash directory
+ *                         entry node.
+ * @dent: the directory entry to zero out
+ */
+static inline void zero_dent_node_unused(struct ubifs_dent_node *dent)
+{
+	dent->padding1 = 0;
+}
+
+/**
+ * zero_trun_node_unused - zero out unused fields of an on-flash truncation
+ *                         node.
+ * @trun: the truncation node to zero out
+ */
+static inline void zero_trun_node_unused(struct ubifs_trun_node *trun)
+{
+	memset(trun->padding, 0, 12);
+}
+
+static void ubifs_add_auth_dirt(struct ubifs_info *c, int lnum)
+{
+	if (ubifs_authenticated(c))
+		ubifs_add_dirt(c, lnum, ubifs_auth_node_sz(c));
+}
+
+/**
+ * reserve_space - reserve space in the journal.
+ * @c: UBIFS file-system description object
+ * @jhead: journal head number
+ * @len: node length
+ *
+ * This function reserves space in journal head @head. If the reservation
+ * succeeded, the journal head stays locked and later has to be unlocked using
+ * 'release_head()'. Returns zero in case of success, %-EAGAIN if commit has to
+ * be done, and other negative error codes in case of other failures.
+ */
+static int reserve_space(struct ubifs_info *c, int jhead, int len)
+{
+	int err = 0, err1, retries = 0, avail, lnum, offs, squeeze;
+	struct ubifs_wbuf *wbuf = &c->jheads[jhead].wbuf;
+
+	/*
+	 * Typically, the base head has smaller nodes written to it, so it is
+	 * better to try to allocate space at the ends of eraseblocks. This is
+	 * what the squeeze parameter does.
+	 */
+	ubifs_assert(c, !c->ro_media && !c->ro_mount);
+	squeeze = (jhead == BASEHD);
+again:
+	mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
+
+	if (c->ro_error) {
+		err = -EROFS;
+		goto out_unlock;
+	}
+
+	avail = c->leb_size - wbuf->offs - wbuf->used;
+	if (wbuf->lnum != -1 && avail >= len)
+		return 0;
+
+	/*
+	 * Write buffer wasn't seek'ed or there is no enough space - look for an
+	 * LEB with some empty space.
+	 */
+	lnum = ubifs_find_free_space(c, len, &offs, squeeze);
+	if (lnum >= 0)
+		goto out;
+
+	err = lnum;
+	if (err != -ENOSPC)
+		goto out_unlock;
+
+	/*
+	 * No free space, we have to run garbage collector to make
+	 * some. But the write-buffer mutex has to be unlocked because
+	 * GC also takes it.
+	 */
+	dbg_jnl("no free space in jhead %s, run GC", dbg_jhead(jhead));
+	mutex_unlock(&wbuf->io_mutex);
+
+	lnum = ubifs_garbage_collect(c, 0);
+	if (lnum < 0) {
+		err = lnum;
+		if (err != -ENOSPC)
+			return err;
+
+		/*
+		 * GC could not make a free LEB. But someone else may
+		 * have allocated new bud for this journal head,
+		 * because we dropped @wbuf->io_mutex, so try once
+		 * again.
+		 */
+		dbg_jnl("GC couldn't make a free LEB for jhead %s",
+			dbg_jhead(jhead));
+		if (retries++ < 2) {
+			dbg_jnl("retry (%d)", retries);
+			goto again;
+		}
+
+		dbg_jnl("return -ENOSPC");
+		return err;
+	}
+
+	mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
+	dbg_jnl("got LEB %d for jhead %s", lnum, dbg_jhead(jhead));
+	avail = c->leb_size - wbuf->offs - wbuf->used;
+
+	if (wbuf->lnum != -1 && avail >= len) {
+		/*
+		 * Someone else has switched the journal head and we have
+		 * enough space now. This happens when more than one process is
+		 * trying to write to the same journal head at the same time.
+		 */
+		dbg_jnl("return LEB %d back, already have LEB %d:%d",
+			lnum, wbuf->lnum, wbuf->offs + wbuf->used);
+		err = ubifs_return_leb(c, lnum);
+		if (err)
+			goto out_unlock;
+		return 0;
+	}
+
+	offs = 0;
+
+out:
+	/*
+	 * Make sure we synchronize the write-buffer before we add the new bud
+	 * to the log. Otherwise we may have a power cut after the log
+	 * reference node for the last bud (@lnum) is written but before the
+	 * write-buffer data are written to the next-to-last bud
+	 * (@wbuf->lnum). And the effect would be that the recovery would see
+	 * that there is corruption in the next-to-last bud.
+	 */
+	err = ubifs_wbuf_sync_nolock(wbuf);
+	if (err)
+		goto out_return;
+	err = ubifs_add_bud_to_log(c, jhead, lnum, offs);
+	if (err)
+		goto out_return;
+	err = ubifs_wbuf_seek_nolock(wbuf, lnum, offs);
+	if (err)
+		goto out_unlock;
+
+	return 0;
+
+out_unlock:
+	mutex_unlock(&wbuf->io_mutex);
+	return err;
+
+out_return:
+	/* An error occurred and the LEB has to be returned to lprops */
+	ubifs_assert(c, err < 0);
+	err1 = ubifs_return_leb(c, lnum);
+	if (err1 && err == -EAGAIN)
+		/*
+		 * Return original error code only if it is not %-EAGAIN,
+		 * which is not really an error. Otherwise, return the error
+		 * code of 'ubifs_return_leb()'.
+		 */
+		err = err1;
+	mutex_unlock(&wbuf->io_mutex);
+	return err;
+}
+
+static int ubifs_hash_nodes(struct ubifs_info *c, void *node,
+			     int len, struct shash_desc *hash)
+{
+	int auth_node_size = ubifs_auth_node_sz(c);
+	int err;
+
+	while (1) {
+		const struct ubifs_ch *ch = node;
+		int nodelen = le32_to_cpu(ch->len);
+
+		ubifs_assert(c, len >= auth_node_size);
+
+		if (len == auth_node_size)
+			break;
+
+		ubifs_assert(c, len > nodelen);
+		ubifs_assert(c, ch->magic == cpu_to_le32(UBIFS_NODE_MAGIC));
+
+		err = ubifs_shash_update(c, hash, (void *)node, nodelen);
+		if (err)
+			return err;
+
+		node += ALIGN(nodelen, 8);
+		len -= ALIGN(nodelen, 8);
+	}
+
+	return ubifs_prepare_auth_node(c, node, hash);
+}
+
+/**
+ * write_head - write data to a journal head.
+ * @c: UBIFS file-system description object
+ * @jhead: journal head
+ * @buf: buffer to write
+ * @len: length to write
+ * @lnum: LEB number written is returned here
+ * @offs: offset written is returned here
+ * @sync: non-zero if the write-buffer has to by synchronized
+ *
+ * This function writes data to the reserved space of journal head @jhead.
+ * Returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+static int write_head(struct ubifs_info *c, int jhead, void *buf, int len,
+		      int *lnum, int *offs, int sync)
+{
+	int err;
+	struct ubifs_wbuf *wbuf = &c->jheads[jhead].wbuf;
+
+	ubifs_assert(c, jhead != GCHD);
+
+	*lnum = c->jheads[jhead].wbuf.lnum;
+	*offs = c->jheads[jhead].wbuf.offs + c->jheads[jhead].wbuf.used;
+	dbg_jnl("jhead %s, LEB %d:%d, len %d",
+		dbg_jhead(jhead), *lnum, *offs, len);
+
+	if (ubifs_authenticated(c)) {
+		err = ubifs_hash_nodes(c, buf, len, c->jheads[jhead].log_hash);
+		if (err)
+			return err;
+	}
+
+	err = ubifs_wbuf_write_nolock(wbuf, buf, len);
+	if (err)
+		return err;
+	if (sync)
+		err = ubifs_wbuf_sync_nolock(wbuf);
+	return err;
+}
+
+/**
+ * make_reservation - reserve journal space.
+ * @c: UBIFS file-system description object
+ * @jhead: journal head
+ * @len: how many bytes to reserve
+ *
+ * This function makes space reservation in journal head @jhead. The function
+ * takes the commit lock and locks the journal head, and the caller has to
+ * unlock the head and finish the reservation with 'finish_reservation()'.
+ * Returns zero in case of success and a negative error code in case of
+ * failure.
+ *
+ * Note, the journal head may be unlocked as soon as the data is written, while
+ * the commit lock has to be released after the data has been added to the
+ * TNC.
+ */
+static int make_reservation(struct ubifs_info *c, int jhead, int len)
+{
+	int err, cmt_retries = 0, nospc_retries = 0;
+
+again:
+	down_read(&c->commit_sem);
+	err = reserve_space(c, jhead, len);
+	if (!err)
+		/* c->commit_sem will get released via finish_reservation(). */
+		return 0;
+	up_read(&c->commit_sem);
+
+	if (err == -ENOSPC) {
+		/*
+		 * GC could not make any progress. We should try to commit
+		 * once because it could make some dirty space and GC would
+		 * make progress, so make the error -EAGAIN so that the below
+		 * will commit and re-try.
+		 */
+		if (nospc_retries++ < 2) {
+			dbg_jnl("no space, retry");
+			err = -EAGAIN;
+		}
+
+		/*
+		 * This means that the budgeting is incorrect. We always have
+		 * to be able to write to the media, because all operations are
+		 * budgeted. Deletions are not budgeted, though, but we reserve
+		 * an extra LEB for them.
+		 */
+	}
+
+	if (err != -EAGAIN)
+		goto out;
+
+	/*
+	 * -EAGAIN means that the journal is full or too large, or the above
+	 * code wants to do one commit. Do this and re-try.
+	 */
+	if (cmt_retries > 128) {
+		/*
+		 * This should not happen unless the journal size limitations
+		 * are too tough.
+		 */
+		ubifs_err(c, "stuck in space allocation");
+		err = -ENOSPC;
+		goto out;
+	} else if (cmt_retries > 32)
+		ubifs_warn(c, "too many space allocation re-tries (%d)",
+			   cmt_retries);
+
+	dbg_jnl("-EAGAIN, commit and retry (retried %d times)",
+		cmt_retries);
+	cmt_retries += 1;
+
+	err = ubifs_run_commit(c);
+	if (err)
+		return err;
+	goto again;
+
+out:
+	ubifs_err(c, "cannot reserve %d bytes in jhead %d, error %d",
+		  len, jhead, err);
+	if (err == -ENOSPC) {
+		/* This are some budgeting problems, print useful information */
+		down_write(&c->commit_sem);
+		dump_stack();
+		ubifs_dump_budg(c, &c->bi);
+		ubifs_dump_lprops(c);
+		cmt_retries = dbg_check_lprops(c);
+		up_write(&c->commit_sem);
+	}
+	return err;
+}
+
+/**
+ * release_head - release a journal head.
+ * @c: UBIFS file-system description object
+ * @jhead: journal head
+ *
+ * This function releases journal head @jhead which was locked by
+ * the 'make_reservation()' function. It has to be called after each successful
+ * 'make_reservation()' invocation.
+ */
+static inline void release_head(struct ubifs_info *c, int jhead)
+{
+	mutex_unlock(&c->jheads[jhead].wbuf.io_mutex);
+}
+
+/**
+ * finish_reservation - finish a reservation.
+ * @c: UBIFS file-system description object
+ *
+ * This function finishes journal space reservation. It must be called after
+ * 'make_reservation()'.
+ */
+static void finish_reservation(struct ubifs_info *c)
+{
+	up_read(&c->commit_sem);
+}
+
+/**
+ * get_dent_type - translate VFS inode mode to UBIFS directory entry type.
+ * @mode: inode mode
+ */
+static int get_dent_type(int mode)
+{
+	switch (mode & S_IFMT) {
+	case S_IFREG:
+		return UBIFS_ITYPE_REG;
+	case S_IFDIR:
+		return UBIFS_ITYPE_DIR;
+	case S_IFLNK:
+		return UBIFS_ITYPE_LNK;
+	case S_IFBLK:
+		return UBIFS_ITYPE_BLK;
+	case S_IFCHR:
+		return UBIFS_ITYPE_CHR;
+	case S_IFIFO:
+		return UBIFS_ITYPE_FIFO;
+	case S_IFSOCK:
+		return UBIFS_ITYPE_SOCK;
+	default:
+		BUG();
+	}
+	return 0;
+}
+
+/**
+ * pack_inode - pack an inode node.
+ * @c: UBIFS file-system description object
+ * @ino: buffer in which to pack inode node
+ * @inode: inode to pack
+ * @last: indicates the last node of the group
+ */
+static void pack_inode(struct ubifs_info *c, struct ubifs_ino_node *ino,
+		       const struct inode *inode, int last)
+{
+	int data_len = 0, last_reference = !inode->i_nlink;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+
+	ino->ch.node_type = UBIFS_INO_NODE;
+	ino_key_init_flash(c, &ino->key, inode->i_ino);
+	ino->creat_sqnum = cpu_to_le64(ui->creat_sqnum);
+	ino->atime_sec  = cpu_to_le64(inode_get_atime_sec(inode));
+	ino->atime_nsec = cpu_to_le32(inode_get_atime_nsec(inode));
+	ino->ctime_sec  = cpu_to_le64(inode_get_ctime_sec(inode));
+	ino->ctime_nsec = cpu_to_le32(inode_get_ctime_nsec(inode));
+	ino->mtime_sec  = cpu_to_le64(inode_get_mtime_sec(inode));
+	ino->mtime_nsec = cpu_to_le32(inode_get_mtime_nsec(inode));
+	ino->uid   = cpu_to_le32(i_uid_read(inode));
+	ino->gid   = cpu_to_le32(i_gid_read(inode));
+	ino->mode  = cpu_to_le32(inode->i_mode);
+	ino->flags = cpu_to_le32(ui->flags);
+	ino->size  = cpu_to_le64(ui->ui_size);
+	ino->nlink = cpu_to_le32(inode->i_nlink);
+	ino->compr_type  = cpu_to_le16(ui->compr_type);
+	ino->data_len    = cpu_to_le32(ui->data_len);
+	ino->xattr_cnt   = cpu_to_le32(ui->xattr_cnt);
+	ino->xattr_size  = cpu_to_le32(ui->xattr_size);
+	ino->xattr_names = cpu_to_le32(ui->xattr_names);
+	zero_ino_node_unused(ino);
+
+	/*
+	 * Drop the attached data if this is a deletion inode, the data is not
+	 * needed anymore.
+	 */
+	if (!last_reference) {
+		memcpy(ino->data, ui->data, ui->data_len);
+		data_len = ui->data_len;
+	}
+
+	ubifs_prep_grp_node(c, ino, UBIFS_INO_NODE_SZ + data_len, last);
+}
+
+/**
+ * mark_inode_clean - mark UBIFS inode as clean.
+ * @c: UBIFS file-system description object
+ * @ui: UBIFS inode to mark as clean
+ *
+ * This helper function marks UBIFS inode @ui as clean by cleaning the
+ * @ui->dirty flag and releasing its budget. Note, VFS may still treat the
+ * inode as dirty and try to write it back, but 'ubifs_write_inode()' would
+ * just do nothing.
+ */
+static void mark_inode_clean(struct ubifs_info *c, struct ubifs_inode *ui)
+{
+	if (ui->dirty)
+		ubifs_release_dirty_inode_budget(c, ui);
+	ui->dirty = 0;
+}
+
+static void set_dent_cookie(struct ubifs_info *c, struct ubifs_dent_node *dent)
+{
+	if (c->double_hash)
+		dent->cookie = (__force __le32) get_random_u32();
+	else
+		dent->cookie = 0;
+}
+
+/**
+ * ubifs_jnl_update - update inode.
+ * @c: UBIFS file-system description object
+ * @dir: parent inode or host inode in case of extended attributes
+ * @nm: directory entry name
+ * @inode: inode to update
+ * @deletion: indicates a directory entry deletion i.e unlink or rmdir
+ * @xent: non-zero if the directory entry is an extended attribute entry
+ * @in_orphan: indicates whether the @inode is in orphan list
+ *
+ * This function updates an inode by writing a directory entry (or extended
+ * attribute entry), the inode itself, and the parent directory inode (or the
+ * host inode) to the journal.
+ *
+ * The function writes the host inode @dir last, which is important in case of
+ * extended attributes. Indeed, then we guarantee that if the host inode gets
+ * synchronized (with 'fsync()'), and the write-buffer it sits in gets flushed,
+ * the extended attribute inode gets flushed too. And this is exactly what the
+ * user expects - synchronizing the host inode synchronizes its extended
+ * attributes. Similarly, this guarantees that if @dir is synchronized, its
+ * directory entry corresponding to @nm gets synchronized too.
+ *
+ * If the inode (@inode) or the parent directory (@dir) are synchronous, this
+ * function synchronizes the write-buffer.
+ *
+ * This function marks the @dir and @inode inodes as clean and returns zero on
+ * success. In case of failure, a negative error code is returned.
+ */
+int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
+		     const struct fscrypt_name *nm, const struct inode *inode,
+		     int deletion, int xent, int in_orphan)
+{
+	int err, dlen, ilen, len, lnum, ino_offs, dent_offs, orphan_added = 0;
+	int aligned_dlen, aligned_ilen, sync = IS_DIRSYNC(dir);
+	int last_reference = !!(deletion && inode->i_nlink == 0);
+	struct ubifs_inode *ui = ubifs_inode(inode);
+	struct ubifs_inode *host_ui = ubifs_inode(dir);
+	struct ubifs_dent_node *dent;
+	struct ubifs_ino_node *ino;
+	union ubifs_key dent_key, ino_key;
+	u8 hash_dent[UBIFS_HASH_ARR_SZ];
+	u8 hash_ino[UBIFS_HASH_ARR_SZ];
+	u8 hash_ino_host[UBIFS_HASH_ARR_SZ];
+
+	ubifs_assert(c, mutex_is_locked(&host_ui->ui_mutex));
+
+	dlen = UBIFS_DENT_NODE_SZ + fname_len(nm) + 1;
+	ilen = UBIFS_INO_NODE_SZ;
+
+	/*
+	 * If the last reference to the inode is being deleted, then there is
+	 * no need to attach and write inode data, it is being deleted anyway.
+	 * And if the inode is being deleted, no need to synchronize
+	 * write-buffer even if the inode is synchronous.
+	 */
+	if (!last_reference) {
+		ilen += ui->data_len;
+		sync |= IS_SYNC(inode);
+	}
+
+	aligned_dlen = ALIGN(dlen, 8);
+	aligned_ilen = ALIGN(ilen, 8);
+
+	len = aligned_dlen + aligned_ilen + UBIFS_INO_NODE_SZ;
+	/* Make sure to also account for extended attributes */
+	if (ubifs_authenticated(c))
+		len += ALIGN(host_ui->data_len, 8) + ubifs_auth_node_sz(c);
+	else
+		len += host_ui->data_len;
+
+	dent = kzalloc(len, GFP_NOFS);
+	if (!dent)
+		return -ENOMEM;
+
+	/* Make reservation before allocating sequence numbers */
+	err = make_reservation(c, BASEHD, len);
+	if (err)
+		goto out_free;
+
+	if (!xent) {
+		dent->ch.node_type = UBIFS_DENT_NODE;
+		if (fname_name(nm) == NULL)
+			dent_key_init_hash(c, &dent_key, dir->i_ino, nm->hash);
+		else
+			dent_key_init(c, &dent_key, dir->i_ino, nm);
+	} else {
+		dent->ch.node_type = UBIFS_XENT_NODE;
+		xent_key_init(c, &dent_key, dir->i_ino, nm);
+	}
+
+	key_write(c, &dent_key, dent->key);
+	dent->inum = deletion ? 0 : cpu_to_le64(inode->i_ino);
+	dent->type = get_dent_type(inode->i_mode);
+	dent->nlen = cpu_to_le16(fname_len(nm));
+	memcpy(dent->name, fname_name(nm), fname_len(nm));
+	dent->name[fname_len(nm)] = '\0';
+	set_dent_cookie(c, dent);
+
+	zero_dent_node_unused(dent);
+	ubifs_prep_grp_node(c, dent, dlen, 0);
+	err = ubifs_node_calc_hash(c, dent, hash_dent);
+	if (err)
+		goto out_release;
+
+	ino = (void *)dent + aligned_dlen;
+	pack_inode(c, ino, inode, 0);
+	err = ubifs_node_calc_hash(c, ino, hash_ino);
+	if (err)
+		goto out_release;
+
+	ino = (void *)ino + aligned_ilen;
+	pack_inode(c, ino, dir, 1);
+	err = ubifs_node_calc_hash(c, ino, hash_ino_host);
+	if (err)
+		goto out_release;
+
+	if (last_reference && !in_orphan) {
+		err = ubifs_add_orphan(c, inode->i_ino);
+		if (err) {
+			release_head(c, BASEHD);
+			goto out_finish;
+		}
+		ui->del_cmtno = c->cmt_no;
+		orphan_added = 1;
+	}
+
+	err = write_head(c, BASEHD, dent, len, &lnum, &dent_offs, sync);
+	if (err)
+		goto out_release;
+	if (!sync) {
+		struct ubifs_wbuf *wbuf = &c->jheads[BASEHD].wbuf;
+
+		ubifs_wbuf_add_ino_nolock(wbuf, inode->i_ino);
+		ubifs_wbuf_add_ino_nolock(wbuf, dir->i_ino);
+	}
+	release_head(c, BASEHD);
+	kfree(dent);
+	ubifs_add_auth_dirt(c, lnum);
+
+	if (deletion) {
+		if (fname_name(nm) == NULL)
+			err = ubifs_tnc_remove_dh(c, &dent_key, nm->minor_hash);
+		else
+			err = ubifs_tnc_remove_nm(c, &dent_key, nm);
+		if (err)
+			goto out_ro;
+		err = ubifs_add_dirt(c, lnum, dlen);
+	} else
+		err = ubifs_tnc_add_nm(c, &dent_key, lnum, dent_offs, dlen,
+				       hash_dent, nm);
+	if (err)
+		goto out_ro;
+
+	/*
+	 * Note, we do not remove the inode from TNC even if the last reference
+	 * to it has just been deleted, because the inode may still be opened.
+	 * Instead, the inode has been added to orphan lists and the orphan
+	 * subsystem will take further care about it.
+	 */
+	ino_key_init(c, &ino_key, inode->i_ino);
+	ino_offs = dent_offs + aligned_dlen;
+	err = ubifs_tnc_add(c, &ino_key, lnum, ino_offs, ilen, hash_ino);
+	if (err)
+		goto out_ro;
+
+	ino_key_init(c, &ino_key, dir->i_ino);
+	ino_offs += aligned_ilen;
+	err = ubifs_tnc_add(c, &ino_key, lnum, ino_offs,
+			    UBIFS_INO_NODE_SZ + host_ui->data_len, hash_ino_host);
+	if (err)
+		goto out_ro;
+
+	if (in_orphan && inode->i_nlink)
+		ubifs_delete_orphan(c, inode->i_ino);
+
+	finish_reservation(c);
+	spin_lock(&ui->ui_lock);
+	ui->synced_i_size = ui->ui_size;
+	spin_unlock(&ui->ui_lock);
+	if (xent) {
+		spin_lock(&host_ui->ui_lock);
+		host_ui->synced_i_size = host_ui->ui_size;
+		spin_unlock(&host_ui->ui_lock);
+	}
+	mark_inode_clean(c, ui);
+	mark_inode_clean(c, host_ui);
+	return 0;
+
+out_finish:
+	finish_reservation(c);
+out_free:
+	kfree(dent);
+	return err;
+
+out_release:
+	release_head(c, BASEHD);
+	kfree(dent);
+out_ro:
+	ubifs_ro_mode(c, err);
+	if (orphan_added)
+		ubifs_delete_orphan(c, inode->i_ino);
+	finish_reservation(c);
+	return err;
+}
+
+/**
+ * ubifs_jnl_write_data - write a data node to the journal.
+ * @c: UBIFS file-system description object
+ * @inode: inode the data node belongs to
+ * @key: node key
+ * @buf: buffer to write
+ * @len: data length (must not exceed %UBIFS_BLOCK_SIZE)
+ *
+ * This function writes a data node to the journal. Returns %0 if the data node
+ * was successfully written, and a negative error code in case of failure.
+ */
+int ubifs_jnl_write_data(struct ubifs_info *c, const struct inode *inode,
+			 const union ubifs_key *key, const void *buf, int len)
+{
+	struct ubifs_data_node *data;
+	int err, lnum, offs, compr_type, out_len, compr_len, auth_len;
+	int dlen = COMPRESSED_DATA_NODE_BUF_SZ, allocated = 1;
+	int write_len;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+	bool encrypted = IS_ENCRYPTED(inode);
+	u8 hash[UBIFS_HASH_ARR_SZ];
+
+	dbg_jnlk(key, "ino %lu, blk %u, len %d, key ",
+		(unsigned long)key_inum(c, key), key_block(c, key), len);
+	ubifs_assert(c, len <= UBIFS_BLOCK_SIZE);
+
+	if (encrypted)
+		dlen += UBIFS_CIPHER_BLOCK_SIZE;
+
+	auth_len = ubifs_auth_node_sz(c);
+
+	data = kmalloc(dlen + auth_len, GFP_NOFS | __GFP_NOWARN);
+	if (!data) {
+		/*
+		 * Fall-back to the write reserve buffer. Note, we might be
+		 * currently on the memory reclaim path, when the kernel is
+		 * trying to free some memory by writing out dirty pages. The
+		 * write reserve buffer helps us to guarantee that we are
+		 * always able to write the data.
+		 */
+		allocated = 0;
+		mutex_lock(&c->write_reserve_mutex);
+		data = c->write_reserve_buf;
+	}
+
+	data->ch.node_type = UBIFS_DATA_NODE;
+	key_write(c, key, &data->key);
+	data->size = cpu_to_le32(len);
+
+	if (!(ui->flags & UBIFS_COMPR_FL))
+		/* Compression is disabled for this inode */
+		compr_type = UBIFS_COMPR_NONE;
+	else
+		compr_type = ui->compr_type;
+
+	out_len = compr_len = dlen - UBIFS_DATA_NODE_SZ;
+	ubifs_compress(c, buf, len, &data->data, &compr_len, &compr_type);
+	ubifs_assert(c, compr_len <= UBIFS_BLOCK_SIZE);
+
+	if (encrypted) {
+		err = ubifs_encrypt(inode, data, compr_len, &out_len, key_block(c, key));
+		if (err)
+			goto out_free;
+
+	} else {
+		data->compr_size = 0;
+		out_len = compr_len;
+	}
+
+	dlen = UBIFS_DATA_NODE_SZ + out_len;
+	if (ubifs_authenticated(c))
+		write_len = ALIGN(dlen, 8) + auth_len;
+	else
+		write_len = dlen;
+
+	data->compr_type = cpu_to_le16(compr_type);
+
+	/* Make reservation before allocating sequence numbers */
+	err = make_reservation(c, DATAHD, write_len);
+	if (err)
+		goto out_free;
+
+	ubifs_prepare_node(c, data, dlen, 0);
+	err = write_head(c, DATAHD, data, write_len, &lnum, &offs, 0);
+	if (err)
+		goto out_release;
+
+	err = ubifs_node_calc_hash(c, data, hash);
+	if (err)
+		goto out_release;
+
+	ubifs_wbuf_add_ino_nolock(&c->jheads[DATAHD].wbuf, key_inum(c, key));
+	release_head(c, DATAHD);
+
+	ubifs_add_auth_dirt(c, lnum);
+
+	err = ubifs_tnc_add(c, key, lnum, offs, dlen, hash);
+	if (err)
+		goto out_ro;
+
+	finish_reservation(c);
+	if (!allocated)
+		mutex_unlock(&c->write_reserve_mutex);
+	else
+		kfree(data);
+	return 0;
+
+out_release:
+	release_head(c, DATAHD);
+out_ro:
+	ubifs_ro_mode(c, err);
+	finish_reservation(c);
+out_free:
+	if (!allocated)
+		mutex_unlock(&c->write_reserve_mutex);
+	else
+		kfree(data);
+	return err;
+}
+
+/**
+ * ubifs_jnl_write_inode - flush inode to the journal.
+ * @c: UBIFS file-system description object
+ * @inode: inode to flush
+ *
+ * This function writes inode @inode to the journal. If the inode is
+ * synchronous, it also synchronizes the write-buffer. Returns zero in case of
+ * success and a negative error code in case of failure.
+ */
+int ubifs_jnl_write_inode(struct ubifs_info *c, const struct inode *inode)
+{
+	int err, lnum, offs;
+	struct ubifs_ino_node *ino, *ino_start;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+	int sync = 0, write_len = 0, ilen = UBIFS_INO_NODE_SZ;
+	int last_reference = !inode->i_nlink;
+	int kill_xattrs = ui->xattr_cnt && last_reference;
+	u8 hash[UBIFS_HASH_ARR_SZ];
+
+	dbg_jnl("ino %lu, nlink %u", inode->i_ino, inode->i_nlink);
+
+	/*
+	 * If the inode is being deleted, do not write the attached data. No
+	 * need to synchronize the write-buffer either.
+	 */
+	if (!last_reference) {
+		ilen += ui->data_len;
+		sync = IS_SYNC(inode);
+	} else if (kill_xattrs) {
+		write_len += UBIFS_INO_NODE_SZ * ui->xattr_cnt;
+	}
+
+	if (ubifs_authenticated(c))
+		write_len += ALIGN(ilen, 8) + ubifs_auth_node_sz(c);
+	else
+		write_len += ilen;
+
+	ino_start = ino = kmalloc(write_len, GFP_NOFS);
+	if (!ino)
+		return -ENOMEM;
+
+	/* Make reservation before allocating sequence numbers */
+	err = make_reservation(c, BASEHD, write_len);
+	if (err)
+		goto out_free;
+
+	if (kill_xattrs) {
+		union ubifs_key key;
+		struct fscrypt_name nm = {0};
+		struct inode *xino;
+		struct ubifs_dent_node *xent, *pxent = NULL;
+
+		if (ui->xattr_cnt > ubifs_xattr_max_cnt(c)) {
+			err = -EPERM;
+			ubifs_err(c, "Cannot delete inode, it has too much xattrs!");
+			goto out_release;
+		}
+
+		lowest_xent_key(c, &key, inode->i_ino);
+		while (1) {
+			xent = ubifs_tnc_next_ent(c, &key, &nm);
+			if (IS_ERR(xent)) {
+				err = PTR_ERR(xent);
+				if (err == -ENOENT)
+					break;
+
+				kfree(pxent);
+				goto out_release;
+			}
+
+			fname_name(&nm) = xent->name;
+			fname_len(&nm) = le16_to_cpu(xent->nlen);
+
+			xino = ubifs_iget(c->vfs_sb, le64_to_cpu(xent->inum));
+			if (IS_ERR(xino)) {
+				err = PTR_ERR(xino);
+				ubifs_err(c, "dead directory entry '%s', error %d",
+					  xent->name, err);
+				ubifs_ro_mode(c, err);
+				kfree(pxent);
+				kfree(xent);
+				goto out_release;
+			}
+			ubifs_assert(c, ubifs_inode(xino)->xattr);
+
+			clear_nlink(xino);
+			pack_inode(c, ino, xino, 0);
+			ino = (void *)ino + UBIFS_INO_NODE_SZ;
+			iput(xino);
+
+			kfree(pxent);
+			pxent = xent;
+			key_read(c, &xent->key, &key);
+		}
+		kfree(pxent);
+	}
+
+	pack_inode(c, ino, inode, 1);
+	err = ubifs_node_calc_hash(c, ino, hash);
+	if (err)
+		goto out_release;
+
+	err = write_head(c, BASEHD, ino_start, write_len, &lnum, &offs, sync);
+	if (err)
+		goto out_release;
+	if (!sync)
+		ubifs_wbuf_add_ino_nolock(&c->jheads[BASEHD].wbuf,
+					  inode->i_ino);
+	release_head(c, BASEHD);
+
+	if (last_reference) {
+		err = ubifs_tnc_remove_ino(c, inode->i_ino);
+		if (err)
+			goto out_ro;
+		ubifs_delete_orphan(c, inode->i_ino);
+		err = ubifs_add_dirt(c, lnum, write_len);
+	} else {
+		union ubifs_key key;
+
+		ubifs_add_auth_dirt(c, lnum);
+
+		ino_key_init(c, &key, inode->i_ino);
+		err = ubifs_tnc_add(c, &key, lnum, offs, ilen, hash);
+	}
+	if (err)
+		goto out_ro;
+
+	finish_reservation(c);
+	spin_lock(&ui->ui_lock);
+	ui->synced_i_size = ui->ui_size;
+	spin_unlock(&ui->ui_lock);
+	kfree(ino_start);
+	return 0;
+
+out_release:
+	release_head(c, BASEHD);
+out_ro:
+	ubifs_ro_mode(c, err);
+	finish_reservation(c);
+out_free:
+	kfree(ino_start);
+	return err;
+}
+
+/**
+ * ubifs_jnl_delete_inode - delete an inode.
+ * @c: UBIFS file-system description object
+ * @inode: inode to delete
+ *
+ * This function deletes inode @inode which includes removing it from orphans,
+ * deleting it from TNC and, in some cases, writing a deletion inode to the
+ * journal.
+ *
+ * When regular file inodes are unlinked or a directory inode is removed, the
+ * 'ubifs_jnl_update()' function writes a corresponding deletion inode and
+ * direntry to the media, and adds the inode to orphans. After this, when the
+ * last reference to this inode has been dropped, this function is called. In
+ * general, it has to write one more deletion inode to the media, because if
+ * a commit happened between 'ubifs_jnl_update()' and
+ * 'ubifs_jnl_delete_inode()', the deletion inode is not in the journal
+ * anymore, and in fact it might not be on the flash anymore, because it might
+ * have been garbage-collected already. And for optimization reasons UBIFS does
+ * not read the orphan area if it has been unmounted cleanly, so it would have
+ * no indication in the journal that there is a deleted inode which has to be
+ * removed from TNC.
+ *
+ * However, if there was no commit between 'ubifs_jnl_update()' and
+ * 'ubifs_jnl_delete_inode()', then there is no need to write the deletion
+ * inode to the media for the second time. And this is quite a typical case.
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+int ubifs_jnl_delete_inode(struct ubifs_info *c, const struct inode *inode)
+{
+	int err;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+
+	ubifs_assert(c, inode->i_nlink == 0);
+
+	if (ui->xattr_cnt || ui->del_cmtno != c->cmt_no)
+		/* A commit happened for sure or inode hosts xattrs */
+		return ubifs_jnl_write_inode(c, inode);
+
+	down_read(&c->commit_sem);
+	/*
+	 * Check commit number again, because the first test has been done
+	 * without @c->commit_sem, so a commit might have happened.
+	 */
+	if (ui->del_cmtno != c->cmt_no) {
+		up_read(&c->commit_sem);
+		return ubifs_jnl_write_inode(c, inode);
+	}
+
+	err = ubifs_tnc_remove_ino(c, inode->i_ino);
+	if (err)
+		ubifs_ro_mode(c, err);
+	else
+		ubifs_delete_orphan(c, inode->i_ino);
+	up_read(&c->commit_sem);
+	return err;
+}
+
+/**
+ * ubifs_jnl_xrename - cross rename two directory entries.
+ * @c: UBIFS file-system description object
+ * @fst_dir: parent inode of 1st directory entry to exchange
+ * @fst_inode: 1st inode to exchange
+ * @fst_nm: name of 1st inode to exchange
+ * @snd_dir: parent inode of 2nd directory entry to exchange
+ * @snd_inode: 2nd inode to exchange
+ * @snd_nm: name of 2nd inode to exchange
+ * @sync: non-zero if the write-buffer has to be synchronized
+ *
+ * This function implements the cross rename operation which may involve
+ * writing 2 inodes and 2 directory entries. It marks the written inodes as clean
+ * and returns zero on success. In case of failure, a negative error code is
+ * returned.
+ */
+int ubifs_jnl_xrename(struct ubifs_info *c, const struct inode *fst_dir,
+		      const struct inode *fst_inode,
+		      const struct fscrypt_name *fst_nm,
+		      const struct inode *snd_dir,
+		      const struct inode *snd_inode,
+		      const struct fscrypt_name *snd_nm, int sync)
+{
+	union ubifs_key key;
+	struct ubifs_dent_node *dent1, *dent2;
+	int err, dlen1, dlen2, lnum, offs, len, plen = UBIFS_INO_NODE_SZ;
+	int aligned_dlen1, aligned_dlen2;
+	int twoparents = (fst_dir != snd_dir);
+	void *p;
+	u8 hash_dent1[UBIFS_HASH_ARR_SZ];
+	u8 hash_dent2[UBIFS_HASH_ARR_SZ];
+	u8 hash_p1[UBIFS_HASH_ARR_SZ];
+	u8 hash_p2[UBIFS_HASH_ARR_SZ];
+
+	ubifs_assert(c, ubifs_inode(fst_dir)->data_len == 0);
+	ubifs_assert(c, ubifs_inode(snd_dir)->data_len == 0);
+	ubifs_assert(c, mutex_is_locked(&ubifs_inode(fst_dir)->ui_mutex));
+	ubifs_assert(c, mutex_is_locked(&ubifs_inode(snd_dir)->ui_mutex));
+
+	dlen1 = UBIFS_DENT_NODE_SZ + fname_len(snd_nm) + 1;
+	dlen2 = UBIFS_DENT_NODE_SZ + fname_len(fst_nm) + 1;
+	aligned_dlen1 = ALIGN(dlen1, 8);
+	aligned_dlen2 = ALIGN(dlen2, 8);
+
+	len = aligned_dlen1 + aligned_dlen2 + ALIGN(plen, 8);
+	if (twoparents)
+		len += plen;
+
+	len += ubifs_auth_node_sz(c);
+
+	dent1 = kzalloc(len, GFP_NOFS);
+	if (!dent1)
+		return -ENOMEM;
+
+	/* Make reservation before allocating sequence numbers */
+	err = make_reservation(c, BASEHD, len);
+	if (err)
+		goto out_free;
+
+	/* Make new dent for 1st entry */
+	dent1->ch.node_type = UBIFS_DENT_NODE;
+	dent_key_init_flash(c, &dent1->key, snd_dir->i_ino, snd_nm);
+	dent1->inum = cpu_to_le64(fst_inode->i_ino);
+	dent1->type = get_dent_type(fst_inode->i_mode);
+	dent1->nlen = cpu_to_le16(fname_len(snd_nm));
+	memcpy(dent1->name, fname_name(snd_nm), fname_len(snd_nm));
+	dent1->name[fname_len(snd_nm)] = '\0';
+	set_dent_cookie(c, dent1);
+	zero_dent_node_unused(dent1);
+	ubifs_prep_grp_node(c, dent1, dlen1, 0);
+	err = ubifs_node_calc_hash(c, dent1, hash_dent1);
+	if (err)
+		goto out_release;
+
+	/* Make new dent for 2nd entry */
+	dent2 = (void *)dent1 + aligned_dlen1;
+	dent2->ch.node_type = UBIFS_DENT_NODE;
+	dent_key_init_flash(c, &dent2->key, fst_dir->i_ino, fst_nm);
+	dent2->inum = cpu_to_le64(snd_inode->i_ino);
+	dent2->type = get_dent_type(snd_inode->i_mode);
+	dent2->nlen = cpu_to_le16(fname_len(fst_nm));
+	memcpy(dent2->name, fname_name(fst_nm), fname_len(fst_nm));
+	dent2->name[fname_len(fst_nm)] = '\0';
+	set_dent_cookie(c, dent2);
+	zero_dent_node_unused(dent2);
+	ubifs_prep_grp_node(c, dent2, dlen2, 0);
+	err = ubifs_node_calc_hash(c, dent2, hash_dent2);
+	if (err)
+		goto out_release;
+
+	p = (void *)dent2 + aligned_dlen2;
+	if (!twoparents) {
+		pack_inode(c, p, fst_dir, 1);
+		err = ubifs_node_calc_hash(c, p, hash_p1);
+		if (err)
+			goto out_release;
+	} else {
+		pack_inode(c, p, fst_dir, 0);
+		err = ubifs_node_calc_hash(c, p, hash_p1);
+		if (err)
+			goto out_release;
+		p += ALIGN(plen, 8);
+		pack_inode(c, p, snd_dir, 1);
+		err = ubifs_node_calc_hash(c, p, hash_p2);
+		if (err)
+			goto out_release;
+	}
+
+	err = write_head(c, BASEHD, dent1, len, &lnum, &offs, sync);
+	if (err)
+		goto out_release;
+	if (!sync) {
+		struct ubifs_wbuf *wbuf = &c->jheads[BASEHD].wbuf;
+
+		ubifs_wbuf_add_ino_nolock(wbuf, fst_dir->i_ino);
+		ubifs_wbuf_add_ino_nolock(wbuf, snd_dir->i_ino);
+	}
+	release_head(c, BASEHD);
+
+	ubifs_add_auth_dirt(c, lnum);
+
+	dent_key_init(c, &key, snd_dir->i_ino, snd_nm);
+	err = ubifs_tnc_add_nm(c, &key, lnum, offs, dlen1, hash_dent1, snd_nm);
+	if (err)
+		goto out_ro;
+
+	offs += aligned_dlen1;
+	dent_key_init(c, &key, fst_dir->i_ino, fst_nm);
+	err = ubifs_tnc_add_nm(c, &key, lnum, offs, dlen2, hash_dent2, fst_nm);
+	if (err)
+		goto out_ro;
+
+	offs += aligned_dlen2;
+
+	ino_key_init(c, &key, fst_dir->i_ino);
+	err = ubifs_tnc_add(c, &key, lnum, offs, plen, hash_p1);
+	if (err)
+		goto out_ro;
+
+	if (twoparents) {
+		offs += ALIGN(plen, 8);
+		ino_key_init(c, &key, snd_dir->i_ino);
+		err = ubifs_tnc_add(c, &key, lnum, offs, plen, hash_p2);
+		if (err)
+			goto out_ro;
+	}
+
+	finish_reservation(c);
+
+	mark_inode_clean(c, ubifs_inode(fst_dir));
+	if (twoparents)
+		mark_inode_clean(c, ubifs_inode(snd_dir));
+	kfree(dent1);
+	return 0;
+
+out_release:
+	release_head(c, BASEHD);
+out_ro:
+	ubifs_ro_mode(c, err);
+	finish_reservation(c);
+out_free:
+	kfree(dent1);
+	return err;
+}
+
+/**
+ * ubifs_jnl_rename - rename a directory entry.
+ * @c: UBIFS file-system description object
+ * @old_dir: parent inode of directory entry to rename
+ * @old_inode: directory entry's inode to rename
+ * @old_nm: name of the old directory entry to rename
+ * @new_dir: parent inode of directory entry to rename
+ * @new_inode: new directory entry's inode (or directory entry's inode to
+ *		replace)
+ * @new_nm: new name of the new directory entry
+ * @whiteout: whiteout inode
+ * @sync: non-zero if the write-buffer has to be synchronized
+ * @delete_orphan: indicates an orphan entry deletion for @whiteout
+ *
+ * This function implements the re-name operation which may involve writing up
+ * to 4 inodes(new inode, whiteout inode, old and new parent directory inodes)
+ * and 2 directory entries. It marks the written inodes as clean and returns
+ * zero on success. In case of failure, a negative error code is returned.
+ */
+int ubifs_jnl_rename(struct ubifs_info *c, const struct inode *old_dir,
+		     const struct inode *old_inode,
+		     const struct fscrypt_name *old_nm,
+		     const struct inode *new_dir,
+		     const struct inode *new_inode,
+		     const struct fscrypt_name *new_nm,
+		     const struct inode *whiteout, int sync, int delete_orphan)
+{
+	void *p;
+	union ubifs_key key;
+	struct ubifs_dent_node *dent, *dent2;
+	int err, dlen1, dlen2, ilen, wlen, lnum, offs, len, orphan_added = 0;
+	int aligned_dlen1, aligned_dlen2, plen = UBIFS_INO_NODE_SZ;
+	int last_reference = !!(new_inode && new_inode->i_nlink == 0);
+	int move = (old_dir != new_dir);
+	struct ubifs_inode *new_ui, *whiteout_ui;
+	u8 hash_old_dir[UBIFS_HASH_ARR_SZ];
+	u8 hash_new_dir[UBIFS_HASH_ARR_SZ];
+	u8 hash_new_inode[UBIFS_HASH_ARR_SZ];
+	u8 hash_whiteout_inode[UBIFS_HASH_ARR_SZ];
+	u8 hash_dent1[UBIFS_HASH_ARR_SZ];
+	u8 hash_dent2[UBIFS_HASH_ARR_SZ];
+
+	ubifs_assert(c, ubifs_inode(old_dir)->data_len == 0);
+	ubifs_assert(c, ubifs_inode(new_dir)->data_len == 0);
+	ubifs_assert(c, mutex_is_locked(&ubifs_inode(old_dir)->ui_mutex));
+	ubifs_assert(c, mutex_is_locked(&ubifs_inode(new_dir)->ui_mutex));
+
+	dlen1 = UBIFS_DENT_NODE_SZ + fname_len(new_nm) + 1;
+	dlen2 = UBIFS_DENT_NODE_SZ + fname_len(old_nm) + 1;
+	if (new_inode) {
+		new_ui = ubifs_inode(new_inode);
+		ubifs_assert(c, mutex_is_locked(&new_ui->ui_mutex));
+		ilen = UBIFS_INO_NODE_SZ;
+		if (!last_reference)
+			ilen += new_ui->data_len;
+	} else
+		ilen = 0;
+
+	if (whiteout) {
+		whiteout_ui = ubifs_inode(whiteout);
+		ubifs_assert(c, mutex_is_locked(&whiteout_ui->ui_mutex));
+		ubifs_assert(c, whiteout->i_nlink == 1);
+		ubifs_assert(c, !whiteout_ui->dirty);
+		wlen = UBIFS_INO_NODE_SZ;
+		wlen += whiteout_ui->data_len;
+	} else
+		wlen = 0;
+
+	aligned_dlen1 = ALIGN(dlen1, 8);
+	aligned_dlen2 = ALIGN(dlen2, 8);
+	len = aligned_dlen1 + aligned_dlen2 + ALIGN(ilen, 8) +
+	      ALIGN(wlen, 8) + ALIGN(plen, 8);
+	if (move)
+		len += plen;
+
+	len += ubifs_auth_node_sz(c);
+
+	dent = kzalloc(len, GFP_NOFS);
+	if (!dent)
+		return -ENOMEM;
+
+	/* Make reservation before allocating sequence numbers */
+	err = make_reservation(c, BASEHD, len);
+	if (err)
+		goto out_free;
+
+	/* Make new dent */
+	dent->ch.node_type = UBIFS_DENT_NODE;
+	dent_key_init_flash(c, &dent->key, new_dir->i_ino, new_nm);
+	dent->inum = cpu_to_le64(old_inode->i_ino);
+	dent->type = get_dent_type(old_inode->i_mode);
+	dent->nlen = cpu_to_le16(fname_len(new_nm));
+	memcpy(dent->name, fname_name(new_nm), fname_len(new_nm));
+	dent->name[fname_len(new_nm)] = '\0';
+	set_dent_cookie(c, dent);
+	zero_dent_node_unused(dent);
+	ubifs_prep_grp_node(c, dent, dlen1, 0);
+	err = ubifs_node_calc_hash(c, dent, hash_dent1);
+	if (err)
+		goto out_release;
+
+	dent2 = (void *)dent + aligned_dlen1;
+	dent2->ch.node_type = UBIFS_DENT_NODE;
+	dent_key_init_flash(c, &dent2->key, old_dir->i_ino, old_nm);
+
+	if (whiteout) {
+		dent2->inum = cpu_to_le64(whiteout->i_ino);
+		dent2->type = get_dent_type(whiteout->i_mode);
+	} else {
+		/* Make deletion dent */
+		dent2->inum = 0;
+		dent2->type = DT_UNKNOWN;
+	}
+	dent2->nlen = cpu_to_le16(fname_len(old_nm));
+	memcpy(dent2->name, fname_name(old_nm), fname_len(old_nm));
+	dent2->name[fname_len(old_nm)] = '\0';
+	set_dent_cookie(c, dent2);
+	zero_dent_node_unused(dent2);
+	ubifs_prep_grp_node(c, dent2, dlen2, 0);
+	err = ubifs_node_calc_hash(c, dent2, hash_dent2);
+	if (err)
+		goto out_release;
+
+	p = (void *)dent2 + aligned_dlen2;
+	if (new_inode) {
+		pack_inode(c, p, new_inode, 0);
+		err = ubifs_node_calc_hash(c, p, hash_new_inode);
+		if (err)
+			goto out_release;
+
+		p += ALIGN(ilen, 8);
+	}
+
+	if (whiteout) {
+		pack_inode(c, p, whiteout, 0);
+		err = ubifs_node_calc_hash(c, p, hash_whiteout_inode);
+		if (err)
+			goto out_release;
+
+		p += ALIGN(wlen, 8);
+	}
+
+	if (!move) {
+		pack_inode(c, p, old_dir, 1);
+		err = ubifs_node_calc_hash(c, p, hash_old_dir);
+		if (err)
+			goto out_release;
+	} else {
+		pack_inode(c, p, old_dir, 0);
+		err = ubifs_node_calc_hash(c, p, hash_old_dir);
+		if (err)
+			goto out_release;
+
+		p += ALIGN(plen, 8);
+		pack_inode(c, p, new_dir, 1);
+		err = ubifs_node_calc_hash(c, p, hash_new_dir);
+		if (err)
+			goto out_release;
+	}
+
+	if (last_reference) {
+		err = ubifs_add_orphan(c, new_inode->i_ino);
+		if (err) {
+			release_head(c, BASEHD);
+			goto out_finish;
+		}
+		new_ui->del_cmtno = c->cmt_no;
+		orphan_added = 1;
+	}
+
+	err = write_head(c, BASEHD, dent, len, &lnum, &offs, sync);
+	if (err)
+		goto out_release;
+	if (!sync) {
+		struct ubifs_wbuf *wbuf = &c->jheads[BASEHD].wbuf;
+
+		ubifs_wbuf_add_ino_nolock(wbuf, new_dir->i_ino);
+		ubifs_wbuf_add_ino_nolock(wbuf, old_dir->i_ino);
+		if (new_inode)
+			ubifs_wbuf_add_ino_nolock(&c->jheads[BASEHD].wbuf,
+						  new_inode->i_ino);
+		if (whiteout)
+			ubifs_wbuf_add_ino_nolock(&c->jheads[BASEHD].wbuf,
+						  whiteout->i_ino);
+	}
+	release_head(c, BASEHD);
+
+	ubifs_add_auth_dirt(c, lnum);
+
+	dent_key_init(c, &key, new_dir->i_ino, new_nm);
+	err = ubifs_tnc_add_nm(c, &key, lnum, offs, dlen1, hash_dent1, new_nm);
+	if (err)
+		goto out_ro;
+
+	offs += aligned_dlen1;
+	if (whiteout) {
+		dent_key_init(c, &key, old_dir->i_ino, old_nm);
+		err = ubifs_tnc_add_nm(c, &key, lnum, offs, dlen2, hash_dent2, old_nm);
+		if (err)
+			goto out_ro;
+	} else {
+		err = ubifs_add_dirt(c, lnum, dlen2);
+		if (err)
+			goto out_ro;
+
+		dent_key_init(c, &key, old_dir->i_ino, old_nm);
+		err = ubifs_tnc_remove_nm(c, &key, old_nm);
+		if (err)
+			goto out_ro;
+	}
+
+	offs += aligned_dlen2;
+	if (new_inode) {
+		ino_key_init(c, &key, new_inode->i_ino);
+		err = ubifs_tnc_add(c, &key, lnum, offs, ilen, hash_new_inode);
+		if (err)
+			goto out_ro;
+		offs += ALIGN(ilen, 8);
+	}
+
+	if (whiteout) {
+		ino_key_init(c, &key, whiteout->i_ino);
+		err = ubifs_tnc_add(c, &key, lnum, offs, wlen,
+				    hash_whiteout_inode);
+		if (err)
+			goto out_ro;
+		offs += ALIGN(wlen, 8);
+	}
+
+	ino_key_init(c, &key, old_dir->i_ino);
+	err = ubifs_tnc_add(c, &key, lnum, offs, plen, hash_old_dir);
+	if (err)
+		goto out_ro;
+
+	if (move) {
+		offs += ALIGN(plen, 8);
+		ino_key_init(c, &key, new_dir->i_ino);
+		err = ubifs_tnc_add(c, &key, lnum, offs, plen, hash_new_dir);
+		if (err)
+			goto out_ro;
+	}
+
+	if (delete_orphan)
+		ubifs_delete_orphan(c, whiteout->i_ino);
+
+	finish_reservation(c);
+	if (new_inode) {
+		mark_inode_clean(c, new_ui);
+		spin_lock(&new_ui->ui_lock);
+		new_ui->synced_i_size = new_ui->ui_size;
+		spin_unlock(&new_ui->ui_lock);
+	}
+	/*
+	 * No need to mark whiteout inode clean.
+	 * Whiteout doesn't have non-zero size, no need to update
+	 * synced_i_size for whiteout_ui.
+	 */
+	mark_inode_clean(c, ubifs_inode(old_dir));
+	if (move)
+		mark_inode_clean(c, ubifs_inode(new_dir));
+	kfree(dent);
+	return 0;
+
+out_release:
+	release_head(c, BASEHD);
+out_ro:
+	ubifs_ro_mode(c, err);
+	if (orphan_added)
+		ubifs_delete_orphan(c, new_inode->i_ino);
+out_finish:
+	finish_reservation(c);
+out_free:
+	kfree(dent);
+	return err;
+}
+
+/**
+ * truncate_data_node - re-compress/encrypt a truncated data node.
+ * @c: UBIFS file-system description object
+ * @inode: inode which refers to the data node
+ * @block: data block number
+ * @dn: data node to re-compress
+ * @new_len: new length
+ * @dn_size: size of the data node @dn in memory
+ *
+ * This function is used when an inode is truncated and the last data node of
+ * the inode has to be re-compressed/encrypted and re-written.
+ */
+static int truncate_data_node(const struct ubifs_info *c, const struct inode *inode,
+			      unsigned int block, struct ubifs_data_node *dn,
+			      int *new_len, int dn_size)
+{
+	void *buf;
+	int err, dlen, compr_type, out_len, data_size;
+
+	out_len = le32_to_cpu(dn->size);
+	buf = kmalloc_array(out_len, WORST_COMPR_FACTOR, GFP_NOFS);
+	if (!buf)
+		return -ENOMEM;
+
+	dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
+	data_size = dn_size - UBIFS_DATA_NODE_SZ;
+	compr_type = le16_to_cpu(dn->compr_type);
+
+	if (IS_ENCRYPTED(inode)) {
+		err = ubifs_decrypt(inode, dn, &dlen, block);
+		if (err)
+			goto out;
+	}
+
+	if (compr_type == UBIFS_COMPR_NONE) {
+		out_len = *new_len;
+	} else {
+		err = ubifs_decompress(c, &dn->data, dlen, buf, &out_len, compr_type);
+		if (err)
+			goto out;
+
+		ubifs_compress(c, buf, *new_len, &dn->data, &out_len, &compr_type);
+	}
+
+	if (IS_ENCRYPTED(inode)) {
+		err = ubifs_encrypt(inode, dn, out_len, &data_size, block);
+		if (err)
+			goto out;
+
+		out_len = data_size;
+	} else {
+		dn->compr_size = 0;
+	}
+
+	ubifs_assert(c, out_len <= UBIFS_BLOCK_SIZE);
+	dn->compr_type = cpu_to_le16(compr_type);
+	dn->size = cpu_to_le32(*new_len);
+	*new_len = UBIFS_DATA_NODE_SZ + out_len;
+	err = 0;
+out:
+	kfree(buf);
+	return err;
+}
+
+/**
+ * ubifs_jnl_truncate - update the journal for a truncation.
+ * @c: UBIFS file-system description object
+ * @inode: inode to truncate
+ * @old_size: old size
+ * @new_size: new size
+ *
+ * When the size of a file decreases due to truncation, a truncation node is
+ * written, the journal tree is updated, and the last data block is re-written
+ * if it has been affected. The inode is also updated in order to synchronize
+ * the new inode size.
+ *
+ * This function marks the inode as clean and returns zero on success. In case
+ * of failure, a negative error code is returned.
+ */
+int ubifs_jnl_truncate(struct ubifs_info *c, const struct inode *inode,
+		       loff_t old_size, loff_t new_size)
+{
+	union ubifs_key key, to_key;
+	struct ubifs_ino_node *ino;
+	struct ubifs_trun_node *trun;
+	struct ubifs_data_node *dn;
+	int err, dlen, len, lnum, offs, bit, sz, sync = IS_SYNC(inode);
+	int dn_size;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+	ino_t inum = inode->i_ino;
+	unsigned int blk;
+	u8 hash_ino[UBIFS_HASH_ARR_SZ];
+	u8 hash_dn[UBIFS_HASH_ARR_SZ];
+
+	dbg_jnl("ino %lu, size %lld -> %lld",
+		(unsigned long)inum, old_size, new_size);
+	ubifs_assert(c, !ui->data_len);
+	ubifs_assert(c, S_ISREG(inode->i_mode));
+	ubifs_assert(c, mutex_is_locked(&ui->ui_mutex));
+
+	dn_size = COMPRESSED_DATA_NODE_BUF_SZ;
+
+	if (IS_ENCRYPTED(inode))
+		dn_size += UBIFS_CIPHER_BLOCK_SIZE;
+
+	sz =  UBIFS_TRUN_NODE_SZ + UBIFS_INO_NODE_SZ +
+		dn_size + ubifs_auth_node_sz(c);
+
+	ino = kmalloc(sz, GFP_NOFS);
+	if (!ino)
+		return -ENOMEM;
+
+	trun = (void *)ino + UBIFS_INO_NODE_SZ;
+	trun->ch.node_type = UBIFS_TRUN_NODE;
+	trun->inum = cpu_to_le32(inum);
+	trun->old_size = cpu_to_le64(old_size);
+	trun->new_size = cpu_to_le64(new_size);
+	zero_trun_node_unused(trun);
+
+	dlen = new_size & (UBIFS_BLOCK_SIZE - 1);
+	if (dlen) {
+		/* Get last data block so it can be truncated */
+		dn = (void *)trun + UBIFS_TRUN_NODE_SZ;
+		blk = new_size >> UBIFS_BLOCK_SHIFT;
+		data_key_init(c, &key, inum, blk);
+		dbg_jnlk(&key, "last block key ");
+		err = ubifs_tnc_lookup(c, &key, dn);
+		if (err == -ENOENT)
+			dlen = 0; /* Not found (so it is a hole) */
+		else if (err)
+			goto out_free;
+		else {
+			int dn_len = le32_to_cpu(dn->size);
+
+			if (dn_len <= 0 || dn_len > UBIFS_BLOCK_SIZE) {
+				ubifs_err(c, "bad data node (block %u, inode %lu)",
+					  blk, inode->i_ino);
+				ubifs_dump_node(c, dn, dn_size);
+				err = -EUCLEAN;
+				goto out_free;
+			}
+
+			if (dn_len <= dlen)
+				dlen = 0; /* Nothing to do */
+			else {
+				err = truncate_data_node(c, inode, blk, dn,
+						&dlen, dn_size);
+				if (err)
+					goto out_free;
+			}
+		}
+	}
+
+	/* Must make reservation before allocating sequence numbers */
+	len = UBIFS_TRUN_NODE_SZ + UBIFS_INO_NODE_SZ;
+
+	if (ubifs_authenticated(c))
+		len += ALIGN(dlen, 8) + ubifs_auth_node_sz(c);
+	else
+		len += dlen;
+
+	err = make_reservation(c, BASEHD, len);
+	if (err)
+		goto out_free;
+
+	pack_inode(c, ino, inode, 0);
+	err = ubifs_node_calc_hash(c, ino, hash_ino);
+	if (err)
+		goto out_release;
+
+	ubifs_prep_grp_node(c, trun, UBIFS_TRUN_NODE_SZ, dlen ? 0 : 1);
+	if (dlen) {
+		ubifs_prep_grp_node(c, dn, dlen, 1);
+		err = ubifs_node_calc_hash(c, dn, hash_dn);
+		if (err)
+			goto out_release;
+	}
+
+	err = write_head(c, BASEHD, ino, len, &lnum, &offs, sync);
+	if (err)
+		goto out_release;
+	if (!sync)
+		ubifs_wbuf_add_ino_nolock(&c->jheads[BASEHD].wbuf, inum);
+	release_head(c, BASEHD);
+
+	ubifs_add_auth_dirt(c, lnum);
+
+	if (dlen) {
+		sz = offs + UBIFS_INO_NODE_SZ + UBIFS_TRUN_NODE_SZ;
+		err = ubifs_tnc_add(c, &key, lnum, sz, dlen, hash_dn);
+		if (err)
+			goto out_ro;
+	}
+
+	ino_key_init(c, &key, inum);
+	err = ubifs_tnc_add(c, &key, lnum, offs, UBIFS_INO_NODE_SZ, hash_ino);
+	if (err)
+		goto out_ro;
+
+	err = ubifs_add_dirt(c, lnum, UBIFS_TRUN_NODE_SZ);
+	if (err)
+		goto out_ro;
+
+	bit = new_size & (UBIFS_BLOCK_SIZE - 1);
+	blk = (new_size >> UBIFS_BLOCK_SHIFT) + (bit ? 1 : 0);
+	data_key_init(c, &key, inum, blk);
+
+	bit = old_size & (UBIFS_BLOCK_SIZE - 1);
+	blk = (old_size >> UBIFS_BLOCK_SHIFT) - (bit ? 0 : 1);
+	data_key_init(c, &to_key, inum, blk);
+
+	err = ubifs_tnc_remove_range(c, &key, &to_key);
+	if (err)
+		goto out_ro;
+
+	finish_reservation(c);
+	spin_lock(&ui->ui_lock);
+	ui->synced_i_size = ui->ui_size;
+	spin_unlock(&ui->ui_lock);
+	mark_inode_clean(c, ui);
+	kfree(ino);
+	return 0;
+
+out_release:
+	release_head(c, BASEHD);
+out_ro:
+	ubifs_ro_mode(c, err);
+	finish_reservation(c);
+out_free:
+	kfree(ino);
+	return err;
+}
+
+
+/**
+ * ubifs_jnl_delete_xattr - delete an extended attribute.
+ * @c: UBIFS file-system description object
+ * @host: host inode
+ * @inode: extended attribute inode
+ * @nm: extended attribute entry name
+ *
+ * This function delete an extended attribute which is very similar to
+ * un-linking regular files - it writes a deletion xentry, a deletion inode and
+ * updates the target inode. Returns zero in case of success and a negative
+ * error code in case of failure.
+ */
+int ubifs_jnl_delete_xattr(struct ubifs_info *c, const struct inode *host,
+			   const struct inode *inode,
+			   const struct fscrypt_name *nm)
+{
+	int err, xlen, hlen, len, lnum, xent_offs, aligned_xlen, write_len;
+	struct ubifs_dent_node *xent;
+	struct ubifs_ino_node *ino;
+	union ubifs_key xent_key, key1, key2;
+	int sync = IS_DIRSYNC(host);
+	struct ubifs_inode *host_ui = ubifs_inode(host);
+	u8 hash[UBIFS_HASH_ARR_SZ];
+
+	ubifs_assert(c, inode->i_nlink == 0);
+	ubifs_assert(c, mutex_is_locked(&host_ui->ui_mutex));
+
+	/*
+	 * Since we are deleting the inode, we do not bother to attach any data
+	 * to it and assume its length is %UBIFS_INO_NODE_SZ.
+	 */
+	xlen = UBIFS_DENT_NODE_SZ + fname_len(nm) + 1;
+	aligned_xlen = ALIGN(xlen, 8);
+	hlen = host_ui->data_len + UBIFS_INO_NODE_SZ;
+	len = aligned_xlen + UBIFS_INO_NODE_SZ + ALIGN(hlen, 8);
+
+	write_len = len + ubifs_auth_node_sz(c);
+
+	xent = kzalloc(write_len, GFP_NOFS);
+	if (!xent)
+		return -ENOMEM;
+
+	/* Make reservation before allocating sequence numbers */
+	err = make_reservation(c, BASEHD, write_len);
+	if (err) {
+		kfree(xent);
+		return err;
+	}
+
+	xent->ch.node_type = UBIFS_XENT_NODE;
+	xent_key_init(c, &xent_key, host->i_ino, nm);
+	key_write(c, &xent_key, xent->key);
+	xent->inum = 0;
+	xent->type = get_dent_type(inode->i_mode);
+	xent->nlen = cpu_to_le16(fname_len(nm));
+	memcpy(xent->name, fname_name(nm), fname_len(nm));
+	xent->name[fname_len(nm)] = '\0';
+	zero_dent_node_unused(xent);
+	ubifs_prep_grp_node(c, xent, xlen, 0);
+
+	ino = (void *)xent + aligned_xlen;
+	pack_inode(c, ino, inode, 0);
+	ino = (void *)ino + UBIFS_INO_NODE_SZ;
+	pack_inode(c, ino, host, 1);
+	err = ubifs_node_calc_hash(c, ino, hash);
+	if (err)
+		goto out_release;
+
+	err = write_head(c, BASEHD, xent, write_len, &lnum, &xent_offs, sync);
+	if (!sync && !err)
+		ubifs_wbuf_add_ino_nolock(&c->jheads[BASEHD].wbuf, host->i_ino);
+	release_head(c, BASEHD);
+
+	ubifs_add_auth_dirt(c, lnum);
+	kfree(xent);
+	if (err)
+		goto out_ro;
+
+	/* Remove the extended attribute entry from TNC */
+	err = ubifs_tnc_remove_nm(c, &xent_key, nm);
+	if (err)
+		goto out_ro;
+	err = ubifs_add_dirt(c, lnum, xlen);
+	if (err)
+		goto out_ro;
+
+	/*
+	 * Remove all nodes belonging to the extended attribute inode from TNC.
+	 * Well, there actually must be only one node - the inode itself.
+	 */
+	lowest_ino_key(c, &key1, inode->i_ino);
+	highest_ino_key(c, &key2, inode->i_ino);
+	err = ubifs_tnc_remove_range(c, &key1, &key2);
+	if (err)
+		goto out_ro;
+	err = ubifs_add_dirt(c, lnum, UBIFS_INO_NODE_SZ);
+	if (err)
+		goto out_ro;
+
+	/* And update TNC with the new host inode position */
+	ino_key_init(c, &key1, host->i_ino);
+	err = ubifs_tnc_add(c, &key1, lnum, xent_offs + len - hlen, hlen, hash);
+	if (err)
+		goto out_ro;
+
+	finish_reservation(c);
+	spin_lock(&host_ui->ui_lock);
+	host_ui->synced_i_size = host_ui->ui_size;
+	spin_unlock(&host_ui->ui_lock);
+	mark_inode_clean(c, host_ui);
+	return 0;
+
+out_release:
+	kfree(xent);
+	release_head(c, BASEHD);
+out_ro:
+	ubifs_ro_mode(c, err);
+	finish_reservation(c);
+	return err;
+}
+
+/**
+ * ubifs_jnl_change_xattr - change an extended attribute.
+ * @c: UBIFS file-system description object
+ * @inode: extended attribute inode
+ * @host: host inode
+ *
+ * This function writes the updated version of an extended attribute inode and
+ * the host inode to the journal (to the base head). The host inode is written
+ * after the extended attribute inode in order to guarantee that the extended
+ * attribute will be flushed when the inode is synchronized by 'fsync()' and
+ * consequently, the write-buffer is synchronized. This function returns zero
+ * in case of success and a negative error code in case of failure.
+ */
+int ubifs_jnl_change_xattr(struct ubifs_info *c, const struct inode *inode,
+			   const struct inode *host)
+{
+	int err, len1, len2, aligned_len, aligned_len1, lnum, offs;
+	struct ubifs_inode *host_ui = ubifs_inode(host);
+	struct ubifs_ino_node *ino;
+	union ubifs_key key;
+	int sync = IS_DIRSYNC(host);
+	u8 hash_host[UBIFS_HASH_ARR_SZ];
+	u8 hash[UBIFS_HASH_ARR_SZ];
+
+	dbg_jnl("ino %lu, ino %lu", host->i_ino, inode->i_ino);
+	ubifs_assert(c, inode->i_nlink > 0);
+	ubifs_assert(c, mutex_is_locked(&host_ui->ui_mutex));
+
+	len1 = UBIFS_INO_NODE_SZ + host_ui->data_len;
+	len2 = UBIFS_INO_NODE_SZ + ubifs_inode(inode)->data_len;
+	aligned_len1 = ALIGN(len1, 8);
+	aligned_len = aligned_len1 + ALIGN(len2, 8);
+
+	aligned_len += ubifs_auth_node_sz(c);
+
+	ino = kzalloc(aligned_len, GFP_NOFS);
+	if (!ino)
+		return -ENOMEM;
+
+	/* Make reservation before allocating sequence numbers */
+	err = make_reservation(c, BASEHD, aligned_len);
+	if (err)
+		goto out_free;
+
+	pack_inode(c, ino, host, 0);
+	err = ubifs_node_calc_hash(c, ino, hash_host);
+	if (err)
+		goto out_release;
+	pack_inode(c, (void *)ino + aligned_len1, inode, 1);
+	err = ubifs_node_calc_hash(c, (void *)ino + aligned_len1, hash);
+	if (err)
+		goto out_release;
+
+	err = write_head(c, BASEHD, ino, aligned_len, &lnum, &offs, 0);
+	if (!sync && !err) {
+		struct ubifs_wbuf *wbuf = &c->jheads[BASEHD].wbuf;
+
+		ubifs_wbuf_add_ino_nolock(wbuf, host->i_ino);
+		ubifs_wbuf_add_ino_nolock(wbuf, inode->i_ino);
+	}
+	release_head(c, BASEHD);
+	if (err)
+		goto out_ro;
+
+	ubifs_add_auth_dirt(c, lnum);
+
+	ino_key_init(c, &key, host->i_ino);
+	err = ubifs_tnc_add(c, &key, lnum, offs, len1, hash_host);
+	if (err)
+		goto out_ro;
+
+	ino_key_init(c, &key, inode->i_ino);
+	err = ubifs_tnc_add(c, &key, lnum, offs + aligned_len1, len2, hash);
+	if (err)
+		goto out_ro;
+
+	finish_reservation(c);
+	spin_lock(&host_ui->ui_lock);
+	host_ui->synced_i_size = host_ui->ui_size;
+	spin_unlock(&host_ui->ui_lock);
+	mark_inode_clean(c, host_ui);
+	kfree(ino);
+	return 0;
+
+out_release:
+	release_head(c, BASEHD);
+out_ro:
+	ubifs_ro_mode(c, err);
+	finish_reservation(c);
+out_free:
+	kfree(ino);
+	return err;
+}
+
diff --git a/ubifs-utils/libubifs/key.h b/ubifs-utils/libubifs/key.h
new file mode 100644
index 00000000..8142d9d6
--- /dev/null
+++ b/ubifs-utils/libubifs/key.h
@@ -0,0 +1,543 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ */
+
+/*
+ * This header contains various key-related definitions and helper function.
+ * UBIFS allows several key schemes, so we access key fields only via these
+ * helpers. At the moment only one key scheme is supported.
+ *
+ * Simple key scheme
+ * ~~~~~~~~~~~~~~~~~
+ *
+ * Keys are 64-bits long. First 32-bits are inode number (parent inode number
+ * in case of direntry key). Next 3 bits are node type. The last 29 bits are
+ * 4KiB offset in case of inode node, and direntry hash in case of a direntry
+ * node. We use "r5" hash borrowed from reiserfs.
+ */
+
+/*
+ * Lot's of the key helpers require a struct ubifs_info *c as the first parameter.
+ * But we are not using it at all currently. That's designed for future extensions of
+ * different c->key_format. But right now, there is only one key type, UBIFS_SIMPLE_KEY_FMT.
+ */
+
+#ifndef __UBIFS_KEY_H__
+#define __UBIFS_KEY_H__
+
+/**
+ * key_mask_hash - mask a valid hash value.
+ * @val: value to be masked
+ *
+ * We use hash values as offset in directories, so values %0 and %1 are
+ * reserved for "." and "..". %2 is reserved for "end of readdir" marker. This
+ * function makes sure the reserved values are not used.
+ */
+static inline uint32_t key_mask_hash(uint32_t hash)
+{
+	hash &= UBIFS_S_KEY_HASH_MASK;
+	if (unlikely(hash <= 2))
+		hash += 3;
+	return hash;
+}
+
+/**
+ * key_r5_hash - R5 hash function (borrowed from reiserfs).
+ * @s: direntry name
+ * @len: name length
+ */
+static inline uint32_t key_r5_hash(const char *s, int len)
+{
+	uint32_t a = 0;
+	const signed char *str = (const signed char *)s;
+
+	while (len--) {
+		a += *str << 4;
+		a += *str >> 4;
+		a *= 11;
+		str++;
+	}
+
+	return key_mask_hash(a);
+}
+
+/**
+ * key_test_hash - testing hash function.
+ * @str: direntry name
+ * @len: name length
+ */
+static inline uint32_t key_test_hash(const char *str, int len)
+{
+	uint32_t a = 0;
+
+	len = min_t(uint32_t, len, 4);
+	memcpy(&a, str, len);
+	return key_mask_hash(a);
+}
+
+/**
+ * ino_key_init - initialize inode key.
+ * @c: UBIFS file-system description object
+ * @key: key to initialize
+ * @inum: inode number
+ */
+static inline void ino_key_init(const struct ubifs_info *c,
+				union ubifs_key *key, ino_t inum)
+{
+	key->u32[0] = inum;
+	key->u32[1] = UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS;
+}
+
+/**
+ * ino_key_init_flash - initialize on-flash inode key.
+ * @c: UBIFS file-system description object
+ * @k: key to initialize
+ * @inum: inode number
+ */
+static inline void ino_key_init_flash(const struct ubifs_info *c, void *k,
+				      ino_t inum)
+{
+	union ubifs_key *key = k;
+
+	key->j32[0] = cpu_to_le32(inum);
+	key->j32[1] = cpu_to_le32(UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS);
+	memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
+}
+
+/**
+ * lowest_ino_key - get the lowest possible inode key.
+ * @c: UBIFS file-system description object
+ * @key: key to initialize
+ * @inum: inode number
+ */
+static inline void lowest_ino_key(const struct ubifs_info *c,
+				union ubifs_key *key, ino_t inum)
+{
+	key->u32[0] = inum;
+	key->u32[1] = 0;
+}
+
+/**
+ * highest_ino_key - get the highest possible inode key.
+ * @c: UBIFS file-system description object
+ * @key: key to initialize
+ * @inum: inode number
+ */
+static inline void highest_ino_key(const struct ubifs_info *c,
+				union ubifs_key *key, ino_t inum)
+{
+	key->u32[0] = inum;
+	key->u32[1] = 0xffffffff;
+}
+
+/**
+ * dent_key_init - initialize directory entry key.
+ * @c: UBIFS file-system description object
+ * @key: key to initialize
+ * @inum: parent inode number
+ * @nm: direntry name and length. Not a string when encrypted!
+ */
+static inline void dent_key_init(const struct ubifs_info *c,
+				 union ubifs_key *key, ino_t inum,
+				 const struct fscrypt_name *nm)
+{
+	uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
+
+	ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
+	key->u32[0] = inum;
+	key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
+}
+
+/**
+ * dent_key_init_hash - initialize directory entry key without re-calculating
+ *                      hash function.
+ * @c: UBIFS file-system description object
+ * @key: key to initialize
+ * @inum: parent inode number
+ * @hash: direntry name hash
+ */
+static inline void dent_key_init_hash(const struct ubifs_info *c,
+				      union ubifs_key *key, ino_t inum,
+				      uint32_t hash)
+{
+	ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
+	key->u32[0] = inum;
+	key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
+}
+
+/**
+ * dent_key_init_flash - initialize on-flash directory entry key.
+ * @c: UBIFS file-system description object
+ * @k: key to initialize
+ * @inum: parent inode number
+ * @nm: direntry name and length
+ */
+static inline void dent_key_init_flash(const struct ubifs_info *c, void *k,
+				       ino_t inum,
+				       const struct fscrypt_name *nm)
+{
+	union ubifs_key *key = k;
+	uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
+
+	ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
+	key->j32[0] = cpu_to_le32(inum);
+	key->j32[1] = cpu_to_le32(hash |
+				  (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS));
+	memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
+}
+
+/**
+ * lowest_dent_key - get the lowest possible directory entry key.
+ * @c: UBIFS file-system description object
+ * @key: where to store the lowest key
+ * @inum: parent inode number
+ */
+static inline void lowest_dent_key(const struct ubifs_info *c,
+				   union ubifs_key *key, ino_t inum)
+{
+	key->u32[0] = inum;
+	key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS;
+}
+
+/**
+ * xent_key_init - initialize extended attribute entry key.
+ * @c: UBIFS file-system description object
+ * @key: key to initialize
+ * @inum: host inode number
+ * @nm: extended attribute entry name and length
+ */
+static inline void xent_key_init(const struct ubifs_info *c,
+				 union ubifs_key *key, ino_t inum,
+				 const struct fscrypt_name *nm)
+{
+	uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
+
+	ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
+	key->u32[0] = inum;
+	key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);
+}
+
+/**
+ * xent_key_init_flash - initialize on-flash extended attribute entry key.
+ * @c: UBIFS file-system description object
+ * @k: key to initialize
+ * @inum: host inode number
+ * @nm: extended attribute entry name and length
+ */
+static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,
+				       ino_t inum, const struct fscrypt_name *nm)
+{
+	union ubifs_key *key = k;
+	uint32_t hash = c->key_hash(fname_name(nm), fname_len(nm));
+
+	ubifs_assert(c, !(hash & ~UBIFS_S_KEY_HASH_MASK));
+	key->j32[0] = cpu_to_le32(inum);
+	key->j32[1] = cpu_to_le32(hash |
+				  (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS));
+	memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
+}
+
+/**
+ * lowest_xent_key - get the lowest possible extended attribute entry key.
+ * @c: UBIFS file-system description object
+ * @key: where to store the lowest key
+ * @inum: host inode number
+ */
+static inline void lowest_xent_key(const struct ubifs_info *c,
+				   union ubifs_key *key, ino_t inum)
+{
+	key->u32[0] = inum;
+	key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS;
+}
+
+/**
+ * data_key_init - initialize data key.
+ * @c: UBIFS file-system description object
+ * @key: key to initialize
+ * @inum: inode number
+ * @block: block number
+ */
+static inline void data_key_init(const struct ubifs_info *c,
+				 union ubifs_key *key, ino_t inum,
+				 unsigned int block)
+{
+	ubifs_assert(c, !(block & ~UBIFS_S_KEY_BLOCK_MASK));
+	key->u32[0] = inum;
+	key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS);
+}
+
+/**
+ * highest_data_key - get the highest possible data key for an inode.
+ * @c: UBIFS file-system description object
+ * @key: key to initialize
+ * @inum: inode number
+ */
+static inline void highest_data_key(const struct ubifs_info *c,
+				   union ubifs_key *key, ino_t inum)
+{
+	data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK);
+}
+
+/**
+ * trun_key_init - initialize truncation node key.
+ * @c: UBIFS file-system description object
+ * @key: key to initialize
+ * @inum: inode number
+ *
+ * Note, UBIFS does not have truncation keys on the media and this function is
+ * only used for purposes of replay.
+ */
+static inline void trun_key_init(const struct ubifs_info *c,
+				 union ubifs_key *key, ino_t inum)
+{
+	key->u32[0] = inum;
+	key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS;
+}
+
+/**
+ * invalid_key_init - initialize invalid node key.
+ * @c: UBIFS file-system description object
+ * @key: key to initialize
+ *
+ * This is a helper function which marks a @key object as invalid.
+ */
+static inline void invalid_key_init(const struct ubifs_info *c,
+				    union ubifs_key *key)
+{
+	key->u32[0] = 0xDEADBEAF;
+	key->u32[1] = UBIFS_INVALID_KEY;
+}
+
+/**
+ * key_type - get key type.
+ * @c: UBIFS file-system description object
+ * @key: key to get type of
+ */
+static inline int key_type(const struct ubifs_info *c,
+			   const union ubifs_key *key)
+{
+	return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS;
+}
+
+/**
+ * key_type_flash - get type of a on-flash formatted key.
+ * @c: UBIFS file-system description object
+ * @k: key to get type of
+ */
+static inline int key_type_flash(const struct ubifs_info *c, const void *k)
+{
+	const union ubifs_key *key = k;
+
+	return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
+}
+
+/**
+ * key_inum - fetch inode number from key.
+ * @c: UBIFS file-system description object
+ * @k: key to fetch inode number from
+ */
+static inline ino_t key_inum(const struct ubifs_info *c, const void *k)
+{
+	const union ubifs_key *key = k;
+
+	return key->u32[0];
+}
+
+/**
+ * key_inum_flash - fetch inode number from an on-flash formatted key.
+ * @c: UBIFS file-system description object
+ * @k: key to fetch inode number from
+ */
+static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k)
+{
+	const union ubifs_key *key = k;
+
+	return le32_to_cpu(key->j32[0]);
+}
+
+/**
+ * key_hash - get directory entry hash.
+ * @c: UBIFS file-system description object
+ * @key: the key to get hash from
+ */
+static inline uint32_t key_hash(const struct ubifs_info *c,
+				const union ubifs_key *key)
+{
+	return key->u32[1] & UBIFS_S_KEY_HASH_MASK;
+}
+
+/**
+ * key_hash_flash - get directory entry hash from an on-flash formatted key.
+ * @c: UBIFS file-system description object
+ * @k: the key to get hash from
+ */
+static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k)
+{
+	const union ubifs_key *key = k;
+
+	return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK;
+}
+
+/**
+ * key_block - get data block number.
+ * @c: UBIFS file-system description object
+ * @key: the key to get the block number from
+ */
+static inline unsigned int key_block(const struct ubifs_info *c,
+				     const union ubifs_key *key)
+{
+	return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK;
+}
+
+/**
+ * key_block_flash - get data block number from an on-flash formatted key.
+ * @c: UBIFS file-system description object
+ * @k: the key to get the block number from
+ */
+static inline unsigned int key_block_flash(const struct ubifs_info *c,
+					   const void *k)
+{
+	const union ubifs_key *key = k;
+
+	return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK;
+}
+
+/**
+ * key_read - transform a key to in-memory format.
+ * @c: UBIFS file-system description object
+ * @from: the key to transform
+ * @to: the key to store the result
+ */
+static inline void key_read(const struct ubifs_info *c, const void *from,
+			    union ubifs_key *to)
+{
+	const union ubifs_key *f = from;
+
+	to->u32[0] = le32_to_cpu(f->j32[0]);
+	to->u32[1] = le32_to_cpu(f->j32[1]);
+}
+
+/**
+ * key_write - transform a key from in-memory format.
+ * @c: UBIFS file-system description object
+ * @from: the key to transform
+ * @to: the key to store the result
+ */
+static inline void key_write(const struct ubifs_info *c,
+			     const union ubifs_key *from, void *to)
+{
+	union ubifs_key *t = to;
+
+	t->j32[0] = cpu_to_le32(from->u32[0]);
+	t->j32[1] = cpu_to_le32(from->u32[1]);
+	memset(to + 8, 0, UBIFS_MAX_KEY_LEN - 8);
+}
+
+/**
+ * key_write_idx - transform a key from in-memory format for the index.
+ * @c: UBIFS file-system description object
+ * @from: the key to transform
+ * @to: the key to store the result
+ */
+static inline void key_write_idx(const struct ubifs_info *c,
+				 const union ubifs_key *from, void *to)
+{
+	union ubifs_key *t = to;
+
+	t->j32[0] = cpu_to_le32(from->u32[0]);
+	t->j32[1] = cpu_to_le32(from->u32[1]);
+}
+
+/**
+ * key_copy - copy a key.
+ * @c: UBIFS file-system description object
+ * @from: the key to copy from
+ * @to: the key to copy to
+ */
+static inline void key_copy(const struct ubifs_info *c,
+			    const union ubifs_key *from, union ubifs_key *to)
+{
+	to->u64[0] = from->u64[0];
+}
+
+/**
+ * keys_cmp - compare keys.
+ * @c: UBIFS file-system description object
+ * @key1: the first key to compare
+ * @key2: the second key to compare
+ *
+ * This function compares 2 keys and returns %-1 if @key1 is less than
+ * @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2.
+ */
+static inline int keys_cmp(const struct ubifs_info *c,
+			   const union ubifs_key *key1,
+			   const union ubifs_key *key2)
+{
+	if (key1->u32[0] < key2->u32[0])
+		return -1;
+	if (key1->u32[0] > key2->u32[0])
+		return 1;
+	if (key1->u32[1] < key2->u32[1])
+		return -1;
+	if (key1->u32[1] > key2->u32[1])
+		return 1;
+
+	return 0;
+}
+
+/**
+ * keys_eq - determine if keys are equivalent.
+ * @c: UBIFS file-system description object
+ * @key1: the first key to compare
+ * @key2: the second key to compare
+ *
+ * This function compares 2 keys and returns %1 if @key1 is equal to @key2 and
+ * %0 if not.
+ */
+static inline int keys_eq(const struct ubifs_info *c,
+			  const union ubifs_key *key1,
+			  const union ubifs_key *key2)
+{
+	if (key1->u32[0] != key2->u32[0])
+		return 0;
+	if (key1->u32[1] != key2->u32[1])
+		return 0;
+	return 1;
+}
+
+/**
+ * is_hash_key - is a key vulnerable to hash collisions.
+ * @c: UBIFS file-system description object
+ * @key: key
+ *
+ * This function returns %1 if @key is a hashed key or %0 otherwise.
+ */
+static inline int is_hash_key(const struct ubifs_info *c,
+			      const union ubifs_key *key)
+{
+	int type = key_type(c, key);
+
+	return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY;
+}
+
+/**
+ * key_max_inode_size - get maximum file size allowed by current key format.
+ * @c: UBIFS file-system description object
+ */
+static inline unsigned long long key_max_inode_size(const struct ubifs_info *c)
+{
+	switch (c->key_fmt) {
+	case UBIFS_SIMPLE_KEY_FMT:
+		return (1ULL << UBIFS_S_KEY_BLOCK_BITS) * UBIFS_BLOCK_SIZE;
+	default:
+		return 0;
+	}
+}
+
+#endif /* !__UBIFS_KEY_H__ */
diff --git a/ubifs-utils/libubifs/log.c b/ubifs-utils/libubifs/log.c
new file mode 100644
index 00000000..b6ac9c42
--- /dev/null
+++ b/ubifs-utils/libubifs/log.c
@@ -0,0 +1,762 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ */
+
+/*
+ * This file is a part of UBIFS journal implementation and contains various
+ * functions which manipulate the log. The log is a fixed area on the flash
+ * which does not contain any data but refers to buds. The log is a part of the
+ * journal.
+ */
+
+#include "ubifs.h"
+
+static int dbg_check_bud_bytes(struct ubifs_info *c);
+
+/**
+ * ubifs_search_bud - search bud LEB.
+ * @c: UBIFS file-system description object
+ * @lnum: logical eraseblock number to search
+ *
+ * This function searches bud LEB @lnum. Returns bud description object in case
+ * of success and %NULL if there is no bud with this LEB number.
+ */
+struct ubifs_bud *ubifs_search_bud(struct ubifs_info *c, int lnum)
+{
+	struct rb_node *p;
+	struct ubifs_bud *bud;
+
+	spin_lock(&c->buds_lock);
+	p = c->buds.rb_node;
+	while (p) {
+		bud = rb_entry(p, struct ubifs_bud, rb);
+		if (lnum < bud->lnum)
+			p = p->rb_left;
+		else if (lnum > bud->lnum)
+			p = p->rb_right;
+		else {
+			spin_unlock(&c->buds_lock);
+			return bud;
+		}
+	}
+	spin_unlock(&c->buds_lock);
+	return NULL;
+}
+
+/**
+ * ubifs_get_wbuf - get the wbuf associated with a LEB, if there is one.
+ * @c: UBIFS file-system description object
+ * @lnum: logical eraseblock number to search
+ *
+ * This functions returns the wbuf for @lnum or %NULL if there is not one.
+ */
+struct ubifs_wbuf *ubifs_get_wbuf(struct ubifs_info *c, int lnum)
+{
+	struct rb_node *p;
+	struct ubifs_bud *bud;
+	int jhead;
+
+	if (!c->jheads)
+		return NULL;
+
+	spin_lock(&c->buds_lock);
+	p = c->buds.rb_node;
+	while (p) {
+		bud = rb_entry(p, struct ubifs_bud, rb);
+		if (lnum < bud->lnum)
+			p = p->rb_left;
+		else if (lnum > bud->lnum)
+			p = p->rb_right;
+		else {
+			jhead = bud->jhead;
+			spin_unlock(&c->buds_lock);
+			return &c->jheads[jhead].wbuf;
+		}
+	}
+	spin_unlock(&c->buds_lock);
+	return NULL;
+}
+
+/**
+ * empty_log_bytes - calculate amount of empty space in the log.
+ * @c: UBIFS file-system description object
+ */
+static inline long long empty_log_bytes(const struct ubifs_info *c)
+{
+	long long h, t;
+
+	h = (long long)c->lhead_lnum * c->leb_size + c->lhead_offs;
+	t = (long long)c->ltail_lnum * c->leb_size;
+
+	if (h > t)
+		return c->log_bytes - h + t;
+	else if (h != t)
+		return t - h;
+	else if (c->lhead_lnum != c->ltail_lnum)
+		return 0;
+	else
+		return c->log_bytes;
+}
+
+/**
+ * ubifs_add_bud - add bud LEB to the tree of buds and its journal head list.
+ * @c: UBIFS file-system description object
+ * @bud: the bud to add
+ */
+void ubifs_add_bud(struct ubifs_info *c, struct ubifs_bud *bud)
+{
+	struct rb_node **p, *parent = NULL;
+	struct ubifs_bud *b;
+	struct ubifs_jhead *jhead;
+
+	spin_lock(&c->buds_lock);
+	p = &c->buds.rb_node;
+	while (*p) {
+		parent = *p;
+		b = rb_entry(parent, struct ubifs_bud, rb);
+		ubifs_assert(c, bud->lnum != b->lnum);
+		if (bud->lnum < b->lnum)
+			p = &(*p)->rb_left;
+		else
+			p = &(*p)->rb_right;
+	}
+
+	rb_link_node(&bud->rb, parent, p);
+	rb_insert_color(&bud->rb, &c->buds);
+	if (c->jheads) {
+		jhead = &c->jheads[bud->jhead];
+		list_add_tail(&bud->list, &jhead->buds_list);
+	} else
+		ubifs_assert(c, c->replaying && c->ro_mount);
+
+	/*
+	 * Note, although this is a new bud, we anyway account this space now,
+	 * before any data has been written to it, because this is about to
+	 * guarantee fixed mount time, and this bud will anyway be read and
+	 * scanned.
+	 */
+	c->bud_bytes += c->leb_size - bud->start;
+
+	dbg_log("LEB %d:%d, jhead %s, bud_bytes %lld", bud->lnum,
+		bud->start, dbg_jhead(bud->jhead), c->bud_bytes);
+	spin_unlock(&c->buds_lock);
+}
+
+/**
+ * ubifs_add_bud_to_log - add a new bud to the log.
+ * @c: UBIFS file-system description object
+ * @jhead: journal head the bud belongs to
+ * @lnum: LEB number of the bud
+ * @offs: starting offset of the bud
+ *
+ * This function writes a reference node for the new bud LEB @lnum to the log,
+ * and adds it to the buds trees. It also makes sure that log size does not
+ * exceed the 'c->max_bud_bytes' limit. Returns zero in case of success,
+ * %-EAGAIN if commit is required, and a negative error code in case of
+ * failure.
+ */
+int ubifs_add_bud_to_log(struct ubifs_info *c, int jhead, int lnum, int offs)
+{
+	int err;
+	struct ubifs_bud *bud;
+	struct ubifs_ref_node *ref;
+
+	bud = kmalloc(sizeof(struct ubifs_bud), GFP_NOFS);
+	if (!bud)
+		return -ENOMEM;
+	ref = kzalloc(c->ref_node_alsz, GFP_NOFS);
+	if (!ref) {
+		kfree(bud);
+		return -ENOMEM;
+	}
+
+	mutex_lock(&c->log_mutex);
+	ubifs_assert(c, !c->ro_media && !c->ro_mount);
+	if (c->ro_error) {
+		err = -EROFS;
+		goto out_unlock;
+	}
+
+	/* Make sure we have enough space in the log */
+	if (empty_log_bytes(c) - c->ref_node_alsz < c->min_log_bytes) {
+		dbg_log("not enough log space - %lld, required %d",
+			empty_log_bytes(c), c->min_log_bytes);
+		ubifs_commit_required(c);
+		err = -EAGAIN;
+		goto out_unlock;
+	}
+
+	/*
+	 * Make sure the amount of space in buds will not exceed the
+	 * 'c->max_bud_bytes' limit, because we want to guarantee mount time
+	 * limits.
+	 *
+	 * It is not necessary to hold @c->buds_lock when reading @c->bud_bytes
+	 * because we are holding @c->log_mutex. All @c->bud_bytes take place
+	 * when both @c->log_mutex and @c->bud_bytes are locked.
+	 */
+	if (c->bud_bytes + c->leb_size - offs > c->max_bud_bytes) {
+		dbg_log("bud bytes %lld (%lld max), require commit",
+			c->bud_bytes, c->max_bud_bytes);
+		ubifs_commit_required(c);
+		err = -EAGAIN;
+		goto out_unlock;
+	}
+
+	/*
+	 * If the journal is full enough - start background commit. Note, it is
+	 * OK to read 'c->cmt_state' without spinlock because integer reads
+	 * are atomic in the kernel.
+	 */
+	if (c->bud_bytes >= c->bg_bud_bytes &&
+	    c->cmt_state == COMMIT_RESTING) {
+		dbg_log("bud bytes %lld (%lld max), initiate BG commit",
+			c->bud_bytes, c->max_bud_bytes);
+		ubifs_request_bg_commit(c);
+	}
+
+	bud->lnum = lnum;
+	bud->start = offs;
+	bud->jhead = jhead;
+	bud->log_hash = NULL;
+
+	ref->ch.node_type = UBIFS_REF_NODE;
+	ref->lnum = cpu_to_le32(bud->lnum);
+	ref->offs = cpu_to_le32(bud->start);
+	ref->jhead = cpu_to_le32(jhead);
+
+	if (c->lhead_offs > c->leb_size - c->ref_node_alsz) {
+		c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
+		ubifs_assert(c, c->lhead_lnum != c->ltail_lnum);
+		c->lhead_offs = 0;
+	}
+
+	if (c->lhead_offs == 0) {
+		/* Must ensure next log LEB has been unmapped */
+		err = ubifs_leb_unmap(c, c->lhead_lnum);
+		if (err)
+			goto out_unlock;
+	}
+
+	if (bud->start == 0) {
+		/*
+		 * Before writing the LEB reference which refers an empty LEB
+		 * to the log, we have to make sure it is mapped, because
+		 * otherwise we'd risk to refer an LEB with garbage in case of
+		 * an unclean reboot, because the target LEB might have been
+		 * unmapped, but not yet physically erased.
+		 */
+		err = ubifs_leb_map(c, bud->lnum);
+		if (err)
+			goto out_unlock;
+	}
+
+	dbg_log("write ref LEB %d:%d",
+		c->lhead_lnum, c->lhead_offs);
+	err = ubifs_write_node(c, ref, UBIFS_REF_NODE_SZ, c->lhead_lnum,
+			       c->lhead_offs);
+	if (err)
+		goto out_unlock;
+
+	err = ubifs_shash_update(c, c->log_hash, ref, UBIFS_REF_NODE_SZ);
+	if (err)
+		goto out_unlock;
+
+	err = ubifs_shash_copy_state(c, c->log_hash, c->jheads[jhead].log_hash);
+	if (err)
+		goto out_unlock;
+
+	c->lhead_offs += c->ref_node_alsz;
+
+	ubifs_add_bud(c, bud);
+
+	mutex_unlock(&c->log_mutex);
+	kfree(ref);
+	return 0;
+
+out_unlock:
+	mutex_unlock(&c->log_mutex);
+	kfree(ref);
+	kfree(bud);
+	return err;
+}
+
+/**
+ * remove_buds - remove used buds.
+ * @c: UBIFS file-system description object
+ *
+ * This function removes use buds from the buds tree. It does not remove the
+ * buds which are pointed to by journal heads.
+ */
+static void remove_buds(struct ubifs_info *c)
+{
+	struct rb_node *p;
+
+	ubifs_assert(c, list_empty(&c->old_buds));
+	c->cmt_bud_bytes = 0;
+	spin_lock(&c->buds_lock);
+	p = rb_first(&c->buds);
+	while (p) {
+		struct rb_node *p1 = p;
+		struct ubifs_bud *bud;
+		struct ubifs_wbuf *wbuf;
+
+		p = rb_next(p);
+		bud = rb_entry(p1, struct ubifs_bud, rb);
+		wbuf = &c->jheads[bud->jhead].wbuf;
+
+		if (wbuf->lnum == bud->lnum) {
+			/*
+			 * Do not remove buds which are pointed to by journal
+			 * heads (non-closed buds).
+			 */
+			c->cmt_bud_bytes += wbuf->offs - bud->start;
+			dbg_log("preserve %d:%d, jhead %s, bud bytes %d, cmt_bud_bytes %lld",
+				bud->lnum, bud->start, dbg_jhead(bud->jhead),
+				wbuf->offs - bud->start, c->cmt_bud_bytes);
+			bud->start = wbuf->offs;
+		} else {
+			c->cmt_bud_bytes += c->leb_size - bud->start;
+			dbg_log("remove %d:%d, jhead %s, bud bytes %d, cmt_bud_bytes %lld",
+				bud->lnum, bud->start, dbg_jhead(bud->jhead),
+				c->leb_size - bud->start, c->cmt_bud_bytes);
+			rb_erase(p1, &c->buds);
+			/*
+			 * If the commit does not finish, the recovery will need
+			 * to replay the journal, in which case the old buds
+			 * must be unchanged. Do not release them until post
+			 * commit i.e. do not allow them to be garbage
+			 * collected.
+			 */
+			list_move(&bud->list, &c->old_buds);
+		}
+	}
+	spin_unlock(&c->buds_lock);
+}
+
+/**
+ * ubifs_log_start_commit - start commit.
+ * @c: UBIFS file-system description object
+ * @ltail_lnum: return new log tail LEB number
+ *
+ * The commit operation starts with writing "commit start" node to the log and
+ * reference nodes for all journal heads which will define new journal after
+ * the commit has been finished. The commit start and reference nodes are
+ * written in one go to the nearest empty log LEB (hence, when commit is
+ * finished UBIFS may safely unmap all the previous log LEBs). This function
+ * returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+int ubifs_log_start_commit(struct ubifs_info *c, int *ltail_lnum)
+{
+	void *buf;
+	struct ubifs_cs_node *cs;
+	struct ubifs_ref_node *ref;
+	int err, i, max_len, len;
+
+	err = dbg_check_bud_bytes(c);
+	if (err)
+		return err;
+
+	max_len = UBIFS_CS_NODE_SZ + c->jhead_cnt * UBIFS_REF_NODE_SZ;
+	max_len = ALIGN(max_len, c->min_io_size);
+	buf = cs = kmalloc(max_len, GFP_NOFS);
+	if (!buf)
+		return -ENOMEM;
+
+	cs->ch.node_type = UBIFS_CS_NODE;
+	cs->cmt_no = cpu_to_le64(c->cmt_no);
+	ubifs_prepare_node(c, cs, UBIFS_CS_NODE_SZ, 0);
+
+	err = ubifs_shash_init(c, c->log_hash);
+	if (err)
+		goto out;
+
+	err = ubifs_shash_update(c, c->log_hash, cs, UBIFS_CS_NODE_SZ);
+	if (err < 0)
+		goto out;
+
+	/*
+	 * Note, we do not lock 'c->log_mutex' because this is the commit start
+	 * phase and we are exclusively using the log. And we do not lock
+	 * write-buffer because nobody can write to the file-system at this
+	 * phase.
+	 */
+
+	len = UBIFS_CS_NODE_SZ;
+	for (i = 0; i < c->jhead_cnt; i++) {
+		int lnum = c->jheads[i].wbuf.lnum;
+		int offs = c->jheads[i].wbuf.offs;
+
+		if (lnum == -1 || offs == c->leb_size)
+			continue;
+
+		dbg_log("add ref to LEB %d:%d for jhead %s",
+			lnum, offs, dbg_jhead(i));
+		ref = buf + len;
+		ref->ch.node_type = UBIFS_REF_NODE;
+		ref->lnum = cpu_to_le32(lnum);
+		ref->offs = cpu_to_le32(offs);
+		ref->jhead = cpu_to_le32(i);
+
+		ubifs_prepare_node(c, ref, UBIFS_REF_NODE_SZ, 0);
+		len += UBIFS_REF_NODE_SZ;
+
+		err = ubifs_shash_update(c, c->log_hash, ref,
+					 UBIFS_REF_NODE_SZ);
+		if (err)
+			goto out;
+		ubifs_shash_copy_state(c, c->log_hash, c->jheads[i].log_hash);
+	}
+
+	ubifs_pad(c, buf + len, ALIGN(len, c->min_io_size) - len);
+
+	/* Switch to the next log LEB */
+	if (c->lhead_offs) {
+		c->lhead_lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
+		ubifs_assert(c, c->lhead_lnum != c->ltail_lnum);
+		c->lhead_offs = 0;
+	}
+
+	/* Must ensure next LEB has been unmapped */
+	err = ubifs_leb_unmap(c, c->lhead_lnum);
+	if (err)
+		goto out;
+
+	len = ALIGN(len, c->min_io_size);
+	dbg_log("writing commit start at LEB %d:0, len %d", c->lhead_lnum, len);
+	err = ubifs_leb_write(c, c->lhead_lnum, cs, 0, len);
+	if (err)
+		goto out;
+
+	*ltail_lnum = c->lhead_lnum;
+
+	c->lhead_offs += len;
+	ubifs_assert(c, c->lhead_offs < c->leb_size);
+
+	remove_buds(c);
+
+	/*
+	 * We have started the commit and now users may use the rest of the log
+	 * for new writes.
+	 */
+	c->min_log_bytes = 0;
+
+out:
+	kfree(buf);
+	return err;
+}
+
+/**
+ * ubifs_log_end_commit - end commit.
+ * @c: UBIFS file-system description object
+ * @ltail_lnum: new log tail LEB number
+ *
+ * This function is called on when the commit operation was finished. It
+ * moves log tail to new position and updates the master node so that it stores
+ * the new log tail LEB number. Returns zero in case of success and a negative
+ * error code in case of failure.
+ */
+int ubifs_log_end_commit(struct ubifs_info *c, int ltail_lnum)
+{
+	int err;
+
+	/*
+	 * At this phase we have to lock 'c->log_mutex' because UBIFS allows FS
+	 * writes during commit. Its only short "commit" start phase when
+	 * writers are blocked.
+	 */
+	mutex_lock(&c->log_mutex);
+
+	dbg_log("old tail was LEB %d:0, new tail is LEB %d:0",
+		c->ltail_lnum, ltail_lnum);
+
+	c->ltail_lnum = ltail_lnum;
+	/*
+	 * The commit is finished and from now on it must be guaranteed that
+	 * there is always enough space for the next commit.
+	 */
+	c->min_log_bytes = c->leb_size;
+
+	spin_lock(&c->buds_lock);
+	c->bud_bytes -= c->cmt_bud_bytes;
+	spin_unlock(&c->buds_lock);
+
+	err = dbg_check_bud_bytes(c);
+	if (err)
+		goto out;
+
+	err = ubifs_write_master(c);
+
+out:
+	mutex_unlock(&c->log_mutex);
+	return err;
+}
+
+/**
+ * ubifs_log_post_commit - things to do after commit is completed.
+ * @c: UBIFS file-system description object
+ * @old_ltail_lnum: old log tail LEB number
+ *
+ * Release buds only after commit is completed, because they must be unchanged
+ * if recovery is needed.
+ *
+ * Unmap log LEBs only after commit is completed, because they may be needed for
+ * recovery.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_log_post_commit(struct ubifs_info *c, int old_ltail_lnum)
+{
+	int lnum, err = 0;
+
+	while (!list_empty(&c->old_buds)) {
+		struct ubifs_bud *bud;
+
+		bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
+		err = ubifs_return_leb(c, bud->lnum);
+		if (err)
+			return err;
+		list_del(&bud->list);
+		kfree(bud->log_hash);
+		kfree(bud);
+	}
+	mutex_lock(&c->log_mutex);
+	for (lnum = old_ltail_lnum; lnum != c->ltail_lnum;
+	     lnum = ubifs_next_log_lnum(c, lnum)) {
+		dbg_log("unmap log LEB %d", lnum);
+		err = ubifs_leb_unmap(c, lnum);
+		if (err)
+			goto out;
+	}
+out:
+	mutex_unlock(&c->log_mutex);
+	return err;
+}
+
+/**
+ * struct done_ref - references that have been done.
+ * @rb: rb-tree node
+ * @lnum: LEB number
+ */
+struct done_ref {
+	struct rb_node rb;
+	int lnum;
+};
+
+/**
+ * done_already - determine if a reference has been done already.
+ * @done_tree: rb-tree to store references that have been done
+ * @lnum: LEB number of reference
+ *
+ * This function returns %1 if the reference has been done, %0 if not, otherwise
+ * a negative error code is returned.
+ */
+static int done_already(struct rb_root *done_tree, int lnum)
+{
+	struct rb_node **p = &done_tree->rb_node, *parent = NULL;
+	struct done_ref *dr;
+
+	while (*p) {
+		parent = *p;
+		dr = rb_entry(parent, struct done_ref, rb);
+		if (lnum < dr->lnum)
+			p = &(*p)->rb_left;
+		else if (lnum > dr->lnum)
+			p = &(*p)->rb_right;
+		else
+			return 1;
+	}
+
+	dr = kzalloc(sizeof(struct done_ref), GFP_NOFS);
+	if (!dr)
+		return -ENOMEM;
+
+	dr->lnum = lnum;
+
+	rb_link_node(&dr->rb, parent, p);
+	rb_insert_color(&dr->rb, done_tree);
+
+	return 0;
+}
+
+/**
+ * destroy_done_tree - destroy the done tree.
+ * @done_tree: done tree to destroy
+ */
+static void destroy_done_tree(struct rb_root *done_tree)
+{
+	struct done_ref *dr, *n;
+
+	rbtree_postorder_for_each_entry_safe(dr, n, done_tree, rb)
+		kfree(dr);
+}
+
+/**
+ * add_node - add a node to the consolidated log.
+ * @c: UBIFS file-system description object
+ * @buf: buffer to which to add
+ * @lnum: LEB number to which to write is passed and returned here
+ * @offs: offset to where to write is passed and returned here
+ * @node: node to add
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int add_node(struct ubifs_info *c, void *buf, int *lnum, int *offs,
+		    void *node)
+{
+	struct ubifs_ch *ch = node;
+	int len = le32_to_cpu(ch->len), remains = c->leb_size - *offs;
+
+	if (len > remains) {
+		int sz = ALIGN(*offs, c->min_io_size), err;
+
+		ubifs_pad(c, buf + *offs, sz - *offs);
+		err = ubifs_leb_change(c, *lnum, buf, sz);
+		if (err)
+			return err;
+		*lnum = ubifs_next_log_lnum(c, *lnum);
+		*offs = 0;
+	}
+	memcpy(buf + *offs, node, len);
+	*offs += ALIGN(len, 8);
+	return 0;
+}
+
+/**
+ * ubifs_consolidate_log - consolidate the log.
+ * @c: UBIFS file-system description object
+ *
+ * Repeated failed commits could cause the log to be full, but at least 1 LEB is
+ * needed for commit. This function rewrites the reference nodes in the log
+ * omitting duplicates, and failed CS nodes, and leaving no gaps.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_consolidate_log(struct ubifs_info *c)
+{
+	struct ubifs_scan_leb *sleb;
+	struct ubifs_scan_node *snod;
+	struct rb_root done_tree = RB_ROOT;
+	int lnum, err, first = 1, write_lnum, offs = 0;
+	void *buf;
+
+	dbg_rcvry("log tail LEB %d, log head LEB %d", c->ltail_lnum,
+		  c->lhead_lnum);
+	buf = vmalloc(c->leb_size);
+	if (!buf)
+		return -ENOMEM;
+	lnum = c->ltail_lnum;
+	write_lnum = lnum;
+	while (1) {
+		sleb = ubifs_scan(c, lnum, 0, c->sbuf, 0);
+		if (IS_ERR(sleb)) {
+			err = PTR_ERR(sleb);
+			goto out_free;
+		}
+		list_for_each_entry(snod, &sleb->nodes, list) {
+			switch (snod->type) {
+			case UBIFS_REF_NODE: {
+				struct ubifs_ref_node *ref = snod->node;
+				int ref_lnum = le32_to_cpu(ref->lnum);
+
+				err = done_already(&done_tree, ref_lnum);
+				if (err < 0)
+					goto out_scan;
+				if (err != 1) {
+					err = add_node(c, buf, &write_lnum,
+						       &offs, snod->node);
+					if (err)
+						goto out_scan;
+				}
+				break;
+			}
+			case UBIFS_CS_NODE:
+				if (!first)
+					break;
+				err = add_node(c, buf, &write_lnum, &offs,
+					       snod->node);
+				if (err)
+					goto out_scan;
+				first = 0;
+				break;
+			}
+		}
+		ubifs_scan_destroy(sleb);
+		if (lnum == c->lhead_lnum)
+			break;
+		lnum = ubifs_next_log_lnum(c, lnum);
+	}
+	if (offs) {
+		int sz = ALIGN(offs, c->min_io_size);
+
+		ubifs_pad(c, buf + offs, sz - offs);
+		err = ubifs_leb_change(c, write_lnum, buf, sz);
+		if (err)
+			goto out_free;
+		offs = ALIGN(offs, c->min_io_size);
+	}
+	destroy_done_tree(&done_tree);
+	vfree(buf);
+	if (write_lnum == c->lhead_lnum) {
+		ubifs_err(c, "log is too full");
+		return -EINVAL;
+	}
+	/* Unmap remaining LEBs */
+	lnum = write_lnum;
+	do {
+		lnum = ubifs_next_log_lnum(c, lnum);
+		err = ubifs_leb_unmap(c, lnum);
+		if (err)
+			return err;
+	} while (lnum != c->lhead_lnum);
+	c->lhead_lnum = write_lnum;
+	c->lhead_offs = offs;
+	dbg_rcvry("new log head at %d:%d", c->lhead_lnum, c->lhead_offs);
+	return 0;
+
+out_scan:
+	ubifs_scan_destroy(sleb);
+out_free:
+	destroy_done_tree(&done_tree);
+	vfree(buf);
+	return err;
+}
+
+/**
+ * dbg_check_bud_bytes - make sure bud bytes calculation are all right.
+ * @c: UBIFS file-system description object
+ *
+ * This function makes sure the amount of flash space used by closed buds
+ * ('c->bud_bytes' is correct). Returns zero in case of success and %-EINVAL in
+ * case of failure.
+ */
+static int dbg_check_bud_bytes(struct ubifs_info *c)
+{
+	int i, err = 0;
+	struct ubifs_bud *bud;
+	long long bud_bytes = 0;
+
+	if (!dbg_is_chk_gen(c))
+		return 0;
+
+	spin_lock(&c->buds_lock);
+	for (i = 0; i < c->jhead_cnt; i++)
+		list_for_each_entry(bud, &c->jheads[i].buds_list, list)
+			bud_bytes += c->leb_size - bud->start;
+
+	if (c->bud_bytes != bud_bytes) {
+		ubifs_err(c, "bad bud_bytes %lld, calculated %lld",
+			  c->bud_bytes, bud_bytes);
+		err = -EINVAL;
+	}
+	spin_unlock(&c->buds_lock);
+
+	return err;
+}
diff --git a/ubifs-utils/libubifs/lprops.c b/ubifs-utils/libubifs/lprops.c
new file mode 100644
index 00000000..6d6cd85c
--- /dev/null
+++ b/ubifs-utils/libubifs/lprops.c
@@ -0,0 +1,1307 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file implements the functions that access LEB properties and their
+ * categories. LEBs are categorized based on the needs of UBIFS, and the
+ * categories are stored as either heaps or lists to provide a fast way of
+ * finding a LEB in a particular category. For example, UBIFS may need to find
+ * an empty LEB for the journal, or a very dirty LEB for garbage collection.
+ */
+
+#include "ubifs.h"
+
+/**
+ * get_heap_comp_val - get the LEB properties value for heap comparisons.
+ * @lprops: LEB properties
+ * @cat: LEB category
+ */
+static int get_heap_comp_val(struct ubifs_lprops *lprops, int cat)
+{
+	switch (cat) {
+	case LPROPS_FREE:
+		return lprops->free;
+	case LPROPS_DIRTY_IDX:
+		return lprops->free + lprops->dirty;
+	default:
+		return lprops->dirty;
+	}
+}
+
+/**
+ * move_up_lpt_heap - move a new heap entry up as far as possible.
+ * @c: UBIFS file-system description object
+ * @heap: LEB category heap
+ * @lprops: LEB properties to move
+ * @cat: LEB category
+ *
+ * New entries to a heap are added at the bottom and then moved up until the
+ * parent's value is greater.  In the case of LPT's category heaps, the value
+ * is either the amount of free space or the amount of dirty space, depending
+ * on the category.
+ */
+static void move_up_lpt_heap(struct ubifs_info *c, struct ubifs_lpt_heap *heap,
+			     struct ubifs_lprops *lprops, int cat)
+{
+	int val1, val2, hpos;
+
+	hpos = lprops->hpos;
+	if (!hpos)
+		return; /* Already top of the heap */
+	val1 = get_heap_comp_val(lprops, cat);
+	/* Compare to parent and, if greater, move up the heap */
+	do {
+		int ppos = (hpos - 1) / 2;
+
+		val2 = get_heap_comp_val(heap->arr[ppos], cat);
+		if (val2 >= val1)
+			return;
+		/* Greater than parent so move up */
+		heap->arr[ppos]->hpos = hpos;
+		heap->arr[hpos] = heap->arr[ppos];
+		heap->arr[ppos] = lprops;
+		lprops->hpos = ppos;
+		hpos = ppos;
+	} while (hpos);
+}
+
+/**
+ * adjust_lpt_heap - move a changed heap entry up or down the heap.
+ * @c: UBIFS file-system description object
+ * @heap: LEB category heap
+ * @lprops: LEB properties to move
+ * @hpos: heap position of @lprops
+ * @cat: LEB category
+ *
+ * Changed entries in a heap are moved up or down until the parent's value is
+ * greater.  In the case of LPT's category heaps, the value is either the amount
+ * of free space or the amount of dirty space, depending on the category.
+ */
+static void adjust_lpt_heap(struct ubifs_info *c, struct ubifs_lpt_heap *heap,
+			    struct ubifs_lprops *lprops, int hpos, int cat)
+{
+	int val1, val2, val3, cpos;
+
+	val1 = get_heap_comp_val(lprops, cat);
+	/* Compare to parent and, if greater than parent, move up the heap */
+	if (hpos) {
+		int ppos = (hpos - 1) / 2;
+
+		val2 = get_heap_comp_val(heap->arr[ppos], cat);
+		if (val1 > val2) {
+			/* Greater than parent so move up */
+			while (1) {
+				heap->arr[ppos]->hpos = hpos;
+				heap->arr[hpos] = heap->arr[ppos];
+				heap->arr[ppos] = lprops;
+				lprops->hpos = ppos;
+				hpos = ppos;
+				if (!hpos)
+					return;
+				ppos = (hpos - 1) / 2;
+				val2 = get_heap_comp_val(heap->arr[ppos], cat);
+				if (val1 <= val2)
+					return;
+				/* Still greater than parent so keep going */
+			}
+		}
+	}
+
+	/* Not greater than parent, so compare to children */
+	while (1) {
+		/* Compare to left child */
+		cpos = hpos * 2 + 1;
+		if (cpos >= heap->cnt)
+			return;
+		val2 = get_heap_comp_val(heap->arr[cpos], cat);
+		if (val1 < val2) {
+			/* Less than left child, so promote biggest child */
+			if (cpos + 1 < heap->cnt) {
+				val3 = get_heap_comp_val(heap->arr[cpos + 1],
+							 cat);
+				if (val3 > val2)
+					cpos += 1; /* Right child is bigger */
+			}
+			heap->arr[cpos]->hpos = hpos;
+			heap->arr[hpos] = heap->arr[cpos];
+			heap->arr[cpos] = lprops;
+			lprops->hpos = cpos;
+			hpos = cpos;
+			continue;
+		}
+		/* Compare to right child */
+		cpos += 1;
+		if (cpos >= heap->cnt)
+			return;
+		val3 = get_heap_comp_val(heap->arr[cpos], cat);
+		if (val1 < val3) {
+			/* Less than right child, so promote right child */
+			heap->arr[cpos]->hpos = hpos;
+			heap->arr[hpos] = heap->arr[cpos];
+			heap->arr[cpos] = lprops;
+			lprops->hpos = cpos;
+			hpos = cpos;
+			continue;
+		}
+		return;
+	}
+}
+
+/**
+ * add_to_lpt_heap - add LEB properties to a LEB category heap.
+ * @c: UBIFS file-system description object
+ * @lprops: LEB properties to add
+ * @cat: LEB category
+ *
+ * This function returns %1 if @lprops is added to the heap for LEB category
+ * @cat, otherwise %0 is returned because the heap is full.
+ */
+static int add_to_lpt_heap(struct ubifs_info *c, struct ubifs_lprops *lprops,
+			   int cat)
+{
+	struct ubifs_lpt_heap *heap = &c->lpt_heap[cat - 1];
+
+	if (heap->cnt >= heap->max_cnt) {
+		const int b = LPT_HEAP_SZ / 2 - 1;
+		int cpos, val1, val2;
+
+		/* Compare to some other LEB on the bottom of heap */
+		/* Pick a position kind of randomly */
+		cpos = (((size_t)lprops >> 4) & b) + b;
+		ubifs_assert(c, cpos >= b);
+		ubifs_assert(c, cpos < LPT_HEAP_SZ);
+		ubifs_assert(c, cpos < heap->cnt);
+
+		val1 = get_heap_comp_val(lprops, cat);
+		val2 = get_heap_comp_val(heap->arr[cpos], cat);
+		if (val1 > val2) {
+			struct ubifs_lprops *lp;
+
+			lp = heap->arr[cpos];
+			lp->flags &= ~LPROPS_CAT_MASK;
+			lp->flags |= LPROPS_UNCAT;
+			list_add(&lp->list, &c->uncat_list);
+			lprops->hpos = cpos;
+			heap->arr[cpos] = lprops;
+			move_up_lpt_heap(c, heap, lprops, cat);
+			dbg_check_heap(c, heap, cat, lprops->hpos);
+			return 1; /* Added to heap */
+		}
+		dbg_check_heap(c, heap, cat, -1);
+		return 0; /* Not added to heap */
+	} else {
+		lprops->hpos = heap->cnt++;
+		heap->arr[lprops->hpos] = lprops;
+		move_up_lpt_heap(c, heap, lprops, cat);
+		dbg_check_heap(c, heap, cat, lprops->hpos);
+		return 1; /* Added to heap */
+	}
+}
+
+/**
+ * remove_from_lpt_heap - remove LEB properties from a LEB category heap.
+ * @c: UBIFS file-system description object
+ * @lprops: LEB properties to remove
+ * @cat: LEB category
+ */
+static void remove_from_lpt_heap(struct ubifs_info *c,
+				 struct ubifs_lprops *lprops, int cat)
+{
+	struct ubifs_lpt_heap *heap;
+	int hpos = lprops->hpos;
+
+	heap = &c->lpt_heap[cat - 1];
+	ubifs_assert(c, hpos >= 0 && hpos < heap->cnt);
+	ubifs_assert(c, heap->arr[hpos] == lprops);
+	heap->cnt -= 1;
+	if (hpos < heap->cnt) {
+		heap->arr[hpos] = heap->arr[heap->cnt];
+		heap->arr[hpos]->hpos = hpos;
+		adjust_lpt_heap(c, heap, heap->arr[hpos], hpos, cat);
+	}
+	dbg_check_heap(c, heap, cat, -1);
+}
+
+/**
+ * lpt_heap_replace - replace lprops in a category heap.
+ * @c: UBIFS file-system description object
+ * @new_lprops: LEB properties with which to replace
+ * @cat: LEB category
+ *
+ * During commit it is sometimes necessary to copy a pnode (see dirty_cow_pnode)
+ * and the lprops that the pnode contains.  When that happens, references in
+ * the category heaps to those lprops must be updated to point to the new
+ * lprops.  This function does that.
+ */
+static void lpt_heap_replace(struct ubifs_info *c,
+			     struct ubifs_lprops *new_lprops, int cat)
+{
+	struct ubifs_lpt_heap *heap;
+	int hpos = new_lprops->hpos;
+
+	heap = &c->lpt_heap[cat - 1];
+	heap->arr[hpos] = new_lprops;
+}
+
+/**
+ * ubifs_add_to_cat - add LEB properties to a category list or heap.
+ * @c: UBIFS file-system description object
+ * @lprops: LEB properties to add
+ * @cat: LEB category to which to add
+ *
+ * LEB properties are categorized to enable fast find operations.
+ */
+void ubifs_add_to_cat(struct ubifs_info *c, struct ubifs_lprops *lprops,
+		      int cat)
+{
+	switch (cat) {
+	case LPROPS_DIRTY:
+	case LPROPS_DIRTY_IDX:
+	case LPROPS_FREE:
+		if (add_to_lpt_heap(c, lprops, cat))
+			break;
+		/* No more room on heap so make it un-categorized */
+		cat = LPROPS_UNCAT;
+		fallthrough;
+	case LPROPS_UNCAT:
+		list_add(&lprops->list, &c->uncat_list);
+		break;
+	case LPROPS_EMPTY:
+		list_add(&lprops->list, &c->empty_list);
+		break;
+	case LPROPS_FREEABLE:
+		list_add(&lprops->list, &c->freeable_list);
+		c->freeable_cnt += 1;
+		break;
+	case LPROPS_FRDI_IDX:
+		list_add(&lprops->list, &c->frdi_idx_list);
+		break;
+	default:
+		ubifs_assert(c, 0);
+	}
+
+	lprops->flags &= ~LPROPS_CAT_MASK;
+	lprops->flags |= cat;
+	c->in_a_category_cnt += 1;
+	ubifs_assert(c, c->in_a_category_cnt <= c->main_lebs);
+}
+
+/**
+ * ubifs_remove_from_cat - remove LEB properties from a category list or heap.
+ * @c: UBIFS file-system description object
+ * @lprops: LEB properties to remove
+ * @cat: LEB category from which to remove
+ *
+ * LEB properties are categorized to enable fast find operations.
+ */
+static void ubifs_remove_from_cat(struct ubifs_info *c,
+				  struct ubifs_lprops *lprops, int cat)
+{
+	switch (cat) {
+	case LPROPS_DIRTY:
+	case LPROPS_DIRTY_IDX:
+	case LPROPS_FREE:
+		remove_from_lpt_heap(c, lprops, cat);
+		break;
+	case LPROPS_FREEABLE:
+		c->freeable_cnt -= 1;
+		ubifs_assert(c, c->freeable_cnt >= 0);
+		fallthrough;
+	case LPROPS_UNCAT:
+	case LPROPS_EMPTY:
+	case LPROPS_FRDI_IDX:
+		ubifs_assert(c, !list_empty(&lprops->list));
+		list_del(&lprops->list);
+		break;
+	default:
+		ubifs_assert(c, 0);
+	}
+
+	c->in_a_category_cnt -= 1;
+	ubifs_assert(c, c->in_a_category_cnt >= 0);
+}
+
+/**
+ * ubifs_replace_cat - replace lprops in a category list or heap.
+ * @c: UBIFS file-system description object
+ * @old_lprops: LEB properties to replace
+ * @new_lprops: LEB properties with which to replace
+ *
+ * During commit it is sometimes necessary to copy a pnode (see dirty_cow_pnode)
+ * and the lprops that the pnode contains. When that happens, references in
+ * category lists and heaps must be replaced. This function does that.
+ */
+void ubifs_replace_cat(struct ubifs_info *c, struct ubifs_lprops *old_lprops,
+		       struct ubifs_lprops *new_lprops)
+{
+	int cat;
+
+	cat = new_lprops->flags & LPROPS_CAT_MASK;
+	switch (cat) {
+	case LPROPS_DIRTY:
+	case LPROPS_DIRTY_IDX:
+	case LPROPS_FREE:
+		lpt_heap_replace(c, new_lprops, cat);
+		break;
+	case LPROPS_UNCAT:
+	case LPROPS_EMPTY:
+	case LPROPS_FREEABLE:
+	case LPROPS_FRDI_IDX:
+		list_replace(&old_lprops->list, &new_lprops->list);
+		break;
+	default:
+		ubifs_assert(c, 0);
+	}
+}
+
+/**
+ * ubifs_ensure_cat - ensure LEB properties are categorized.
+ * @c: UBIFS file-system description object
+ * @lprops: LEB properties
+ *
+ * A LEB may have fallen off of the bottom of a heap, and ended up as
+ * un-categorized even though it has enough space for us now. If that is the
+ * case this function will put the LEB back onto a heap.
+ */
+void ubifs_ensure_cat(struct ubifs_info *c, struct ubifs_lprops *lprops)
+{
+	int cat = lprops->flags & LPROPS_CAT_MASK;
+
+	if (cat != LPROPS_UNCAT)
+		return;
+	cat = ubifs_categorize_lprops(c, lprops);
+	if (cat == LPROPS_UNCAT)
+		return;
+	ubifs_remove_from_cat(c, lprops, LPROPS_UNCAT);
+	ubifs_add_to_cat(c, lprops, cat);
+}
+
+/**
+ * ubifs_categorize_lprops - categorize LEB properties.
+ * @c: UBIFS file-system description object
+ * @lprops: LEB properties to categorize
+ *
+ * LEB properties are categorized to enable fast find operations. This function
+ * returns the LEB category to which the LEB properties belong. Note however
+ * that if the LEB category is stored as a heap and the heap is full, the
+ * LEB properties may have their category changed to %LPROPS_UNCAT.
+ */
+int ubifs_categorize_lprops(const struct ubifs_info *c,
+			    const struct ubifs_lprops *lprops)
+{
+	if (lprops->flags & LPROPS_TAKEN)
+		return LPROPS_UNCAT;
+
+	if (lprops->free == c->leb_size) {
+		ubifs_assert(c, !(lprops->flags & LPROPS_INDEX));
+		return LPROPS_EMPTY;
+	}
+
+	if (lprops->free + lprops->dirty == c->leb_size) {
+		if (lprops->flags & LPROPS_INDEX)
+			return LPROPS_FRDI_IDX;
+		else
+			return LPROPS_FREEABLE;
+	}
+
+	if (lprops->flags & LPROPS_INDEX) {
+		if (lprops->dirty + lprops->free >= c->min_idx_node_sz)
+			return LPROPS_DIRTY_IDX;
+	} else {
+		if (lprops->dirty >= c->dead_wm &&
+		    lprops->dirty > lprops->free)
+			return LPROPS_DIRTY;
+		if (lprops->free > 0)
+			return LPROPS_FREE;
+	}
+
+	return LPROPS_UNCAT;
+}
+
+/**
+ * change_category - change LEB properties category.
+ * @c: UBIFS file-system description object
+ * @lprops: LEB properties to re-categorize
+ *
+ * LEB properties are categorized to enable fast find operations. When the LEB
+ * properties change they must be re-categorized.
+ */
+static void change_category(struct ubifs_info *c, struct ubifs_lprops *lprops)
+{
+	int old_cat = lprops->flags & LPROPS_CAT_MASK;
+	int new_cat = ubifs_categorize_lprops(c, lprops);
+
+	if (old_cat == new_cat) {
+		struct ubifs_lpt_heap *heap;
+
+		/* lprops on a heap now must be moved up or down */
+		if (new_cat < 1 || new_cat > LPROPS_HEAP_CNT)
+			return; /* Not on a heap */
+		heap = &c->lpt_heap[new_cat - 1];
+		adjust_lpt_heap(c, heap, lprops, lprops->hpos, new_cat);
+	} else {
+		ubifs_remove_from_cat(c, lprops, old_cat);
+		ubifs_add_to_cat(c, lprops, new_cat);
+	}
+}
+
+/**
+ * ubifs_calc_dark - calculate LEB dark space size.
+ * @c: the UBIFS file-system description object
+ * @spc: amount of free and dirty space in the LEB
+ *
+ * This function calculates and returns amount of dark space in an LEB which
+ * has @spc bytes of free and dirty space.
+ *
+ * UBIFS is trying to account the space which might not be usable, and this
+ * space is called "dark space". For example, if an LEB has only %512 free
+ * bytes, it is dark space, because it cannot fit a large data node.
+ */
+int ubifs_calc_dark(const struct ubifs_info *c, int spc)
+{
+	ubifs_assert(c, !(spc & 7));
+
+	if (spc < c->dark_wm)
+		return spc;
+
+	/*
+	 * If we have slightly more space then the dark space watermark, we can
+	 * anyway safely assume it we'll be able to write a node of the
+	 * smallest size there.
+	 */
+	if (spc - c->dark_wm < MIN_WRITE_SZ)
+		return spc - MIN_WRITE_SZ;
+
+	return c->dark_wm;
+}
+
+/**
+ * is_lprops_dirty - determine if LEB properties are dirty.
+ * @c: the UBIFS file-system description object
+ * @lprops: LEB properties to test
+ */
+static int is_lprops_dirty(struct ubifs_info *c, struct ubifs_lprops *lprops)
+{
+	struct ubifs_pnode *pnode;
+	int pos;
+
+	pos = (lprops->lnum - c->main_first) & (UBIFS_LPT_FANOUT - 1);
+	pnode = (struct ubifs_pnode *)container_of(lprops - pos,
+						   struct ubifs_pnode,
+						   lprops[0]);
+	return !test_bit(COW_CNODE, &pnode->flags) &&
+	       test_bit(DIRTY_CNODE, &pnode->flags);
+}
+
+/**
+ * ubifs_change_lp - change LEB properties.
+ * @c: the UBIFS file-system description object
+ * @lp: LEB properties to change
+ * @free: new free space amount
+ * @dirty: new dirty space amount
+ * @flags: new flags
+ * @idx_gc_cnt: change to the count of @idx_gc list
+ *
+ * This function changes LEB properties (@free, @dirty or @flag). However, the
+ * property which has the %LPROPS_NC value is not changed. Returns a pointer to
+ * the updated LEB properties on success and a negative error code on failure.
+ *
+ * Note, the LEB properties may have had to be copied (due to COW) and
+ * consequently the pointer returned may not be the same as the pointer
+ * passed.
+ */
+const struct ubifs_lprops *ubifs_change_lp(struct ubifs_info *c,
+					   const struct ubifs_lprops *lp,
+					   int free, int dirty, int flags,
+					   int idx_gc_cnt)
+{
+	/*
+	 * This is the only function that is allowed to change lprops, so we
+	 * discard the "const" qualifier.
+	 */
+	struct ubifs_lprops *lprops = (struct ubifs_lprops *)lp;
+
+	dbg_lp("LEB %d, free %d, dirty %d, flags %d",
+	       lprops->lnum, free, dirty, flags);
+
+	ubifs_assert(c, mutex_is_locked(&c->lp_mutex));
+	ubifs_assert(c, c->lst.empty_lebs >= 0 &&
+		     c->lst.empty_lebs <= c->main_lebs);
+	ubifs_assert(c, c->freeable_cnt >= 0);
+	ubifs_assert(c, c->freeable_cnt <= c->main_lebs);
+	ubifs_assert(c, c->lst.taken_empty_lebs >= 0);
+	ubifs_assert(c, c->lst.taken_empty_lebs <= c->lst.empty_lebs);
+	ubifs_assert(c, !(c->lst.total_free & 7) && !(c->lst.total_dirty & 7));
+	ubifs_assert(c, !(c->lst.total_dead & 7) && !(c->lst.total_dark & 7));
+	ubifs_assert(c, !(c->lst.total_used & 7));
+	ubifs_assert(c, free == LPROPS_NC || free >= 0);
+	ubifs_assert(c, dirty == LPROPS_NC || dirty >= 0);
+
+	if (!is_lprops_dirty(c, lprops)) {
+		lprops = ubifs_lpt_lookup_dirty(c, lprops->lnum);
+		if (IS_ERR(lprops))
+			return lprops;
+	} else
+		ubifs_assert(c, lprops == ubifs_lpt_lookup_dirty(c, lprops->lnum));
+
+	ubifs_assert(c, !(lprops->free & 7) && !(lprops->dirty & 7));
+
+	spin_lock(&c->space_lock);
+	if ((lprops->flags & LPROPS_TAKEN) && lprops->free == c->leb_size)
+		c->lst.taken_empty_lebs -= 1;
+
+	if (!(lprops->flags & LPROPS_INDEX)) {
+		int old_spc;
+
+		old_spc = lprops->free + lprops->dirty;
+		if (old_spc < c->dead_wm)
+			c->lst.total_dead -= old_spc;
+		else
+			c->lst.total_dark -= ubifs_calc_dark(c, old_spc);
+
+		c->lst.total_used -= c->leb_size - old_spc;
+	}
+
+	if (free != LPROPS_NC) {
+		free = ALIGN(free, 8);
+		c->lst.total_free += free - lprops->free;
+
+		/* Increase or decrease empty LEBs counter if needed */
+		if (free == c->leb_size) {
+			if (lprops->free != c->leb_size)
+				c->lst.empty_lebs += 1;
+		} else if (lprops->free == c->leb_size)
+			c->lst.empty_lebs -= 1;
+		lprops->free = free;
+	}
+
+	if (dirty != LPROPS_NC) {
+		dirty = ALIGN(dirty, 8);
+		c->lst.total_dirty += dirty - lprops->dirty;
+		lprops->dirty = dirty;
+	}
+
+	if (flags != LPROPS_NC) {
+		/* Take care about indexing LEBs counter if needed */
+		if ((lprops->flags & LPROPS_INDEX)) {
+			if (!(flags & LPROPS_INDEX))
+				c->lst.idx_lebs -= 1;
+		} else if (flags & LPROPS_INDEX)
+			c->lst.idx_lebs += 1;
+		lprops->flags = flags;
+	}
+
+	if (!(lprops->flags & LPROPS_INDEX)) {
+		int new_spc;
+
+		new_spc = lprops->free + lprops->dirty;
+		if (new_spc < c->dead_wm)
+			c->lst.total_dead += new_spc;
+		else
+			c->lst.total_dark += ubifs_calc_dark(c, new_spc);
+
+		c->lst.total_used += c->leb_size - new_spc;
+	}
+
+	if ((lprops->flags & LPROPS_TAKEN) && lprops->free == c->leb_size)
+		c->lst.taken_empty_lebs += 1;
+
+	change_category(c, lprops);
+	c->idx_gc_cnt += idx_gc_cnt;
+	spin_unlock(&c->space_lock);
+	return lprops;
+}
+
+/**
+ * ubifs_get_lp_stats - get lprops statistics.
+ * @c: UBIFS file-system description object
+ * @lst: return statistics
+ */
+void ubifs_get_lp_stats(struct ubifs_info *c, struct ubifs_lp_stats *lst)
+{
+	spin_lock(&c->space_lock);
+	memcpy(lst, &c->lst, sizeof(struct ubifs_lp_stats));
+	spin_unlock(&c->space_lock);
+}
+
+/**
+ * ubifs_change_one_lp - change LEB properties.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB to change properties for
+ * @free: amount of free space
+ * @dirty: amount of dirty space
+ * @flags_set: flags to set
+ * @flags_clean: flags to clean
+ * @idx_gc_cnt: change to the count of idx_gc list
+ *
+ * This function changes properties of LEB @lnum. It is a helper wrapper over
+ * 'ubifs_change_lp()' which hides lprops get/release. The arguments are the
+ * same as in case of 'ubifs_change_lp()'. Returns zero in case of success and
+ * a negative error code in case of failure.
+ */
+int ubifs_change_one_lp(struct ubifs_info *c, int lnum, int free, int dirty,
+			int flags_set, int flags_clean, int idx_gc_cnt)
+{
+	int err = 0, flags;
+	const struct ubifs_lprops *lp;
+
+	ubifs_get_lprops(c);
+
+	lp = ubifs_lpt_lookup_dirty(c, lnum);
+	if (IS_ERR(lp)) {
+		err = PTR_ERR(lp);
+		goto out;
+	}
+
+	flags = (lp->flags | flags_set) & ~flags_clean;
+	lp = ubifs_change_lp(c, lp, free, dirty, flags, idx_gc_cnt);
+	if (IS_ERR(lp))
+		err = PTR_ERR(lp);
+
+out:
+	ubifs_release_lprops(c);
+	if (err)
+		ubifs_err(c, "cannot change properties of LEB %d, error %d",
+			  lnum, err);
+	return err;
+}
+
+/**
+ * ubifs_update_one_lp - update LEB properties.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB to change properties for
+ * @free: amount of free space
+ * @dirty: amount of dirty space to add
+ * @flags_set: flags to set
+ * @flags_clean: flags to clean
+ *
+ * This function is the same as 'ubifs_change_one_lp()' but @dirty is added to
+ * current dirty space, not substitutes it.
+ */
+int ubifs_update_one_lp(struct ubifs_info *c, int lnum, int free, int dirty,
+			int flags_set, int flags_clean)
+{
+	int err = 0, flags;
+	const struct ubifs_lprops *lp;
+
+	ubifs_get_lprops(c);
+
+	lp = ubifs_lpt_lookup_dirty(c, lnum);
+	if (IS_ERR(lp)) {
+		err = PTR_ERR(lp);
+		goto out;
+	}
+
+	flags = (lp->flags | flags_set) & ~flags_clean;
+	lp = ubifs_change_lp(c, lp, free, lp->dirty + dirty, flags, 0);
+	if (IS_ERR(lp))
+		err = PTR_ERR(lp);
+
+out:
+	ubifs_release_lprops(c);
+	if (err)
+		ubifs_err(c, "cannot update properties of LEB %d, error %d",
+			  lnum, err);
+	return err;
+}
+
+/**
+ * ubifs_read_one_lp - read LEB properties.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB to read properties for
+ * @lp: where to store read properties
+ *
+ * This helper function reads properties of a LEB @lnum and stores them in @lp.
+ * Returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+int ubifs_read_one_lp(struct ubifs_info *c, int lnum, struct ubifs_lprops *lp)
+{
+	int err = 0;
+	const struct ubifs_lprops *lpp;
+
+	ubifs_get_lprops(c);
+
+	lpp = ubifs_lpt_lookup(c, lnum);
+	if (IS_ERR(lpp)) {
+		err = PTR_ERR(lpp);
+		ubifs_err(c, "cannot read properties of LEB %d, error %d",
+			  lnum, err);
+		goto out;
+	}
+
+	memcpy(lp, lpp, sizeof(struct ubifs_lprops));
+
+out:
+	ubifs_release_lprops(c);
+	return err;
+}
+
+/**
+ * ubifs_fast_find_free - try to find a LEB with free space quickly.
+ * @c: the UBIFS file-system description object
+ *
+ * This function returns LEB properties for a LEB with free space or %NULL if
+ * the function is unable to find a LEB quickly.
+ */
+const struct ubifs_lprops *ubifs_fast_find_free(struct ubifs_info *c)
+{
+	struct ubifs_lprops *lprops;
+	struct ubifs_lpt_heap *heap;
+
+	ubifs_assert(c, mutex_is_locked(&c->lp_mutex));
+
+	heap = &c->lpt_heap[LPROPS_FREE - 1];
+	if (heap->cnt == 0)
+		return NULL;
+
+	lprops = heap->arr[0];
+	ubifs_assert(c, !(lprops->flags & LPROPS_TAKEN));
+	ubifs_assert(c, !(lprops->flags & LPROPS_INDEX));
+	return lprops;
+}
+
+/**
+ * ubifs_fast_find_empty - try to find an empty LEB quickly.
+ * @c: the UBIFS file-system description object
+ *
+ * This function returns LEB properties for an empty LEB or %NULL if the
+ * function is unable to find an empty LEB quickly.
+ */
+const struct ubifs_lprops *ubifs_fast_find_empty(struct ubifs_info *c)
+{
+	struct ubifs_lprops *lprops;
+
+	ubifs_assert(c, mutex_is_locked(&c->lp_mutex));
+
+	if (list_empty(&c->empty_list))
+		return NULL;
+
+	lprops = list_entry(c->empty_list.next, struct ubifs_lprops, list);
+	ubifs_assert(c, !(lprops->flags & LPROPS_TAKEN));
+	ubifs_assert(c, !(lprops->flags & LPROPS_INDEX));
+	ubifs_assert(c, lprops->free == c->leb_size);
+	return lprops;
+}
+
+/**
+ * ubifs_fast_find_freeable - try to find a freeable LEB quickly.
+ * @c: the UBIFS file-system description object
+ *
+ * This function returns LEB properties for a freeable LEB or %NULL if the
+ * function is unable to find a freeable LEB quickly.
+ */
+const struct ubifs_lprops *ubifs_fast_find_freeable(struct ubifs_info *c)
+{
+	struct ubifs_lprops *lprops;
+
+	ubifs_assert(c, mutex_is_locked(&c->lp_mutex));
+
+	if (list_empty(&c->freeable_list))
+		return NULL;
+
+	lprops = list_entry(c->freeable_list.next, struct ubifs_lprops, list);
+	ubifs_assert(c, !(lprops->flags & LPROPS_TAKEN));
+	ubifs_assert(c, !(lprops->flags & LPROPS_INDEX));
+	ubifs_assert(c, lprops->free + lprops->dirty == c->leb_size);
+	ubifs_assert(c, c->freeable_cnt > 0);
+	return lprops;
+}
+
+/**
+ * ubifs_fast_find_frdi_idx - try to find a freeable index LEB quickly.
+ * @c: the UBIFS file-system description object
+ *
+ * This function returns LEB properties for a freeable index LEB or %NULL if the
+ * function is unable to find a freeable index LEB quickly.
+ */
+const struct ubifs_lprops *ubifs_fast_find_frdi_idx(struct ubifs_info *c)
+{
+	struct ubifs_lprops *lprops;
+
+	ubifs_assert(c, mutex_is_locked(&c->lp_mutex));
+
+	if (list_empty(&c->frdi_idx_list))
+		return NULL;
+
+	lprops = list_entry(c->frdi_idx_list.next, struct ubifs_lprops, list);
+	ubifs_assert(c, !(lprops->flags & LPROPS_TAKEN));
+	ubifs_assert(c, (lprops->flags & LPROPS_INDEX));
+	ubifs_assert(c, lprops->free + lprops->dirty == c->leb_size);
+	return lprops;
+}
+
+/*
+ * Everything below is related to debugging.
+ */
+
+/**
+ * dbg_check_cats - check category heaps and lists.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int dbg_check_cats(struct ubifs_info *c)
+{
+	struct ubifs_lprops *lprops;
+	struct list_head *pos;
+	int i, cat;
+
+	if (!dbg_is_chk_gen(c) && !dbg_is_chk_lprops(c))
+		return 0;
+
+	list_for_each_entry(lprops, &c->empty_list, list) {
+		if (lprops->free != c->leb_size) {
+			ubifs_err(c, "non-empty LEB %d on empty list (free %d dirty %d flags %d)",
+				  lprops->lnum, lprops->free, lprops->dirty,
+				  lprops->flags);
+			return -EINVAL;
+		}
+		if (lprops->flags & LPROPS_TAKEN) {
+			ubifs_err(c, "taken LEB %d on empty list (free %d dirty %d flags %d)",
+				  lprops->lnum, lprops->free, lprops->dirty,
+				  lprops->flags);
+			return -EINVAL;
+		}
+	}
+
+	i = 0;
+	list_for_each_entry(lprops, &c->freeable_list, list) {
+		if (lprops->free + lprops->dirty != c->leb_size) {
+			ubifs_err(c, "non-freeable LEB %d on freeable list (free %d dirty %d flags %d)",
+				  lprops->lnum, lprops->free, lprops->dirty,
+				  lprops->flags);
+			return -EINVAL;
+		}
+		if (lprops->flags & LPROPS_TAKEN) {
+			ubifs_err(c, "taken LEB %d on freeable list (free %d dirty %d flags %d)",
+				  lprops->lnum, lprops->free, lprops->dirty,
+				  lprops->flags);
+			return -EINVAL;
+		}
+		i += 1;
+	}
+	if (i != c->freeable_cnt) {
+		ubifs_err(c, "freeable list count %d expected %d", i,
+			  c->freeable_cnt);
+		return -EINVAL;
+	}
+
+	i = 0;
+	list_for_each(pos, &c->idx_gc)
+		i += 1;
+	if (i != c->idx_gc_cnt) {
+		ubifs_err(c, "idx_gc list count %d expected %d", i,
+			  c->idx_gc_cnt);
+		return -EINVAL;
+	}
+
+	list_for_each_entry(lprops, &c->frdi_idx_list, list) {
+		if (lprops->free + lprops->dirty != c->leb_size) {
+			ubifs_err(c, "non-freeable LEB %d on frdi_idx list (free %d dirty %d flags %d)",
+				  lprops->lnum, lprops->free, lprops->dirty,
+				  lprops->flags);
+			return -EINVAL;
+		}
+		if (lprops->flags & LPROPS_TAKEN) {
+			ubifs_err(c, "taken LEB %d on frdi_idx list (free %d dirty %d flags %d)",
+				  lprops->lnum, lprops->free, lprops->dirty,
+				  lprops->flags);
+			return -EINVAL;
+		}
+		if (!(lprops->flags & LPROPS_INDEX)) {
+			ubifs_err(c, "non-index LEB %d on frdi_idx list (free %d dirty %d flags %d)",
+				  lprops->lnum, lprops->free, lprops->dirty,
+				  lprops->flags);
+			return -EINVAL;
+		}
+	}
+
+	for (cat = 1; cat <= LPROPS_HEAP_CNT; cat++) {
+		struct ubifs_lpt_heap *heap = &c->lpt_heap[cat - 1];
+
+		for (i = 0; i < heap->cnt; i++) {
+			lprops = heap->arr[i];
+			if (!lprops) {
+				ubifs_err(c, "null ptr in LPT heap cat %d", cat);
+				return -EINVAL;
+			}
+			if (lprops->hpos != i) {
+				ubifs_err(c, "bad ptr in LPT heap cat %d", cat);
+				return -EINVAL;
+			}
+			if (lprops->flags & LPROPS_TAKEN) {
+				ubifs_err(c, "taken LEB in LPT heap cat %d", cat);
+				return -EINVAL;
+			}
+		}
+	}
+
+	return 0;
+}
+
+void dbg_check_heap(struct ubifs_info *c, struct ubifs_lpt_heap *heap, int cat,
+		    int add_pos)
+{
+	int i = 0, j, err = 0;
+
+	if (!dbg_is_chk_gen(c) && !dbg_is_chk_lprops(c))
+		return;
+
+	for (i = 0; i < heap->cnt; i++) {
+		struct ubifs_lprops *lprops = heap->arr[i];
+		struct ubifs_lprops *lp;
+
+		if (i != add_pos)
+			if ((lprops->flags & LPROPS_CAT_MASK) != cat) {
+				err = 1;
+				goto out;
+			}
+		if (lprops->hpos != i) {
+			err = 2;
+			goto out;
+		}
+		lp = ubifs_lpt_lookup(c, lprops->lnum);
+		if (IS_ERR(lp)) {
+			err = 3;
+			goto out;
+		}
+		if (lprops != lp) {
+			ubifs_err(c, "lprops %zx lp %zx lprops->lnum %d lp->lnum %d",
+				  (size_t)lprops, (size_t)lp, lprops->lnum,
+				  lp->lnum);
+			err = 4;
+			goto out;
+		}
+		for (j = 0; j < i; j++) {
+			lp = heap->arr[j];
+			if (lp == lprops) {
+				err = 5;
+				goto out;
+			}
+			if (lp->lnum == lprops->lnum) {
+				err = 6;
+				goto out;
+			}
+		}
+	}
+out:
+	if (err) {
+		ubifs_err(c, "failed cat %d hpos %d err %d", cat, i, err);
+		dump_stack();
+		ubifs_dump_heap(c, heap, cat);
+	}
+}
+
+/**
+ * scan_check_cb - scan callback.
+ * @c: the UBIFS file-system description object
+ * @lp: LEB properties to scan
+ * @in_tree: whether the LEB properties are in main memory
+ * @lst: lprops statistics to update
+ *
+ * This function returns a code that indicates whether the scan should continue
+ * (%LPT_SCAN_CONTINUE), whether the LEB properties should be added to the tree
+ * in main memory (%LPT_SCAN_ADD), or whether the scan should stop
+ * (%LPT_SCAN_STOP).
+ */
+static int scan_check_cb(struct ubifs_info *c,
+			 const struct ubifs_lprops *lp, int in_tree,
+			 struct ubifs_lp_stats *lst)
+{
+	struct ubifs_scan_leb *sleb;
+	struct ubifs_scan_node *snod;
+	int cat, lnum = lp->lnum, is_idx = 0, used = 0, free, dirty, ret;
+	void *buf = NULL;
+
+	cat = lp->flags & LPROPS_CAT_MASK;
+	if (cat != LPROPS_UNCAT) {
+		cat = ubifs_categorize_lprops(c, lp);
+		if (cat != (lp->flags & LPROPS_CAT_MASK)) {
+			ubifs_err(c, "bad LEB category %d expected %d",
+				  (lp->flags & LPROPS_CAT_MASK), cat);
+			return -EINVAL;
+		}
+	}
+
+	/* Check lp is on its category list (if it has one) */
+	if (in_tree) {
+		struct list_head *list = NULL;
+
+		switch (cat) {
+		case LPROPS_EMPTY:
+			list = &c->empty_list;
+			break;
+		case LPROPS_FREEABLE:
+			list = &c->freeable_list;
+			break;
+		case LPROPS_FRDI_IDX:
+			list = &c->frdi_idx_list;
+			break;
+		case LPROPS_UNCAT:
+			list = &c->uncat_list;
+			break;
+		}
+		if (list) {
+			struct ubifs_lprops *lprops;
+			int found = 0;
+
+			list_for_each_entry(lprops, list, list) {
+				if (lprops == lp) {
+					found = 1;
+					break;
+				}
+			}
+			if (!found) {
+				ubifs_err(c, "bad LPT list (category %d)", cat);
+				return -EINVAL;
+			}
+		}
+	}
+
+	/* Check lp is on its category heap (if it has one) */
+	if (in_tree && cat > 0 && cat <= LPROPS_HEAP_CNT) {
+		struct ubifs_lpt_heap *heap = &c->lpt_heap[cat - 1];
+
+		if ((lp->hpos != -1 && heap->arr[lp->hpos]->lnum != lnum) ||
+		    lp != heap->arr[lp->hpos]) {
+			ubifs_err(c, "bad LPT heap (category %d)", cat);
+			return -EINVAL;
+		}
+	}
+
+	/*
+	 * After an unclean unmount, empty and freeable LEBs
+	 * may contain garbage - do not scan them.
+	 */
+	if (lp->free == c->leb_size) {
+		lst->empty_lebs += 1;
+		lst->total_free += c->leb_size;
+		lst->total_dark += ubifs_calc_dark(c, c->leb_size);
+		return LPT_SCAN_CONTINUE;
+	}
+	if (lp->free + lp->dirty == c->leb_size &&
+	    !(lp->flags & LPROPS_INDEX)) {
+		lst->total_free  += lp->free;
+		lst->total_dirty += lp->dirty;
+		lst->total_dark  +=  ubifs_calc_dark(c, c->leb_size);
+		return LPT_SCAN_CONTINUE;
+	}
+
+	buf = __vmalloc(c->leb_size, GFP_NOFS);
+	if (!buf)
+		return -ENOMEM;
+
+	sleb = ubifs_scan(c, lnum, 0, buf, 0);
+	if (IS_ERR(sleb)) {
+		ret = PTR_ERR(sleb);
+		if (ret == -EUCLEAN) {
+			ubifs_dump_lprops(c);
+			ubifs_dump_budg(c, &c->bi);
+		}
+		goto out;
+	}
+
+	is_idx = -1;
+	list_for_each_entry(snod, &sleb->nodes, list) {
+		int found, level = 0;
+
+		cond_resched();
+
+		if (is_idx == -1)
+			is_idx = (snod->type == UBIFS_IDX_NODE) ? 1 : 0;
+
+		if (is_idx && snod->type != UBIFS_IDX_NODE) {
+			ubifs_err(c, "indexing node in data LEB %d:%d",
+				  lnum, snod->offs);
+			goto out_destroy;
+		}
+
+		if (snod->type == UBIFS_IDX_NODE) {
+			struct ubifs_idx_node *idx = snod->node;
+
+			key_read(c, ubifs_idx_key(c, idx), &snod->key);
+			level = le16_to_cpu(idx->level);
+		}
+
+		found = ubifs_tnc_has_node(c, &snod->key, level, lnum,
+					   snod->offs, is_idx);
+		if (found) {
+			if (found < 0)
+				goto out_destroy;
+			used += ALIGN(snod->len, 8);
+		}
+	}
+
+	free = c->leb_size - sleb->endpt;
+	dirty = sleb->endpt - used;
+
+	if (free > c->leb_size || free < 0 || dirty > c->leb_size ||
+	    dirty < 0) {
+		ubifs_err(c, "bad calculated accounting for LEB %d: free %d, dirty %d",
+			  lnum, free, dirty);
+		goto out_destroy;
+	}
+
+	if (lp->free + lp->dirty == c->leb_size &&
+	    free + dirty == c->leb_size)
+		if ((is_idx && !(lp->flags & LPROPS_INDEX)) ||
+		    (!is_idx && free == c->leb_size) ||
+		    lp->free == c->leb_size) {
+			/*
+			 * Empty or freeable LEBs could contain index
+			 * nodes from an uncompleted commit due to an
+			 * unclean unmount. Or they could be empty for
+			 * the same reason. Or it may simply not have been
+			 * unmapped.
+			 */
+			free = lp->free;
+			dirty = lp->dirty;
+			is_idx = 0;
+		    }
+
+	if (is_idx && lp->free + lp->dirty == free + dirty &&
+	    lnum != c->ihead_lnum) {
+		/*
+		 * After an unclean unmount, an index LEB could have a different
+		 * amount of free space than the value recorded by lprops. That
+		 * is because the in-the-gaps method may use free space or
+		 * create free space (as a side-effect of using ubi_leb_change
+		 * and not writing the whole LEB). The incorrect free space
+		 * value is not a problem because the index is only ever
+		 * allocated empty LEBs, so there will never be an attempt to
+		 * write to the free space at the end of an index LEB - except
+		 * by the in-the-gaps method for which it is not a problem.
+		 */
+		free = lp->free;
+		dirty = lp->dirty;
+	}
+
+	if (lp->free != free || lp->dirty != dirty)
+		goto out_print;
+
+	if (is_idx && !(lp->flags & LPROPS_INDEX)) {
+		if (free == c->leb_size)
+			/* Free but not unmapped LEB, it's fine */
+			is_idx = 0;
+		else {
+			ubifs_err(c, "indexing node without indexing flag");
+			goto out_print;
+		}
+	}
+
+	if (!is_idx && (lp->flags & LPROPS_INDEX)) {
+		ubifs_err(c, "data node with indexing flag");
+		goto out_print;
+	}
+
+	if (free == c->leb_size)
+		lst->empty_lebs += 1;
+
+	if (is_idx)
+		lst->idx_lebs += 1;
+
+	if (!(lp->flags & LPROPS_INDEX))
+		lst->total_used += c->leb_size - free - dirty;
+	lst->total_free += free;
+	lst->total_dirty += dirty;
+
+	if (!(lp->flags & LPROPS_INDEX)) {
+		int spc = free + dirty;
+
+		if (spc < c->dead_wm)
+			lst->total_dead += spc;
+		else
+			lst->total_dark += ubifs_calc_dark(c, spc);
+	}
+
+	ubifs_scan_destroy(sleb);
+	vfree(buf);
+	return LPT_SCAN_CONTINUE;
+
+out_print:
+	ubifs_err(c, "bad accounting of LEB %d: free %d, dirty %d flags %#x, should be free %d, dirty %d",
+		  lnum, lp->free, lp->dirty, lp->flags, free, dirty);
+	ubifs_dump_leb(c, lnum);
+out_destroy:
+	ubifs_scan_destroy(sleb);
+	ret = -EINVAL;
+out:
+	vfree(buf);
+	return ret;
+}
+
+/**
+ * dbg_check_lprops - check all LEB properties.
+ * @c: UBIFS file-system description object
+ *
+ * This function checks all LEB properties and makes sure they are all correct.
+ * It returns zero if everything is fine, %-EINVAL if there is an inconsistency
+ * and other negative error codes in case of other errors. This function is
+ * called while the file system is locked (because of commit start), so no
+ * additional locking is required. Note that locking the LPT mutex would cause
+ * a circular lock dependency with the TNC mutex.
+ */
+int dbg_check_lprops(struct ubifs_info *c)
+{
+	int i, err;
+	struct ubifs_lp_stats lst;
+
+	if (!dbg_is_chk_lprops(c))
+		return 0;
+
+	/*
+	 * As we are going to scan the media, the write buffers have to be
+	 * synchronized.
+	 */
+	for (i = 0; i < c->jhead_cnt; i++) {
+		err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
+		if (err)
+			return err;
+	}
+
+	memset(&lst, 0, sizeof(struct ubifs_lp_stats));
+	err = ubifs_lpt_scan_nolock(c, c->main_first, c->leb_cnt - 1,
+				    (ubifs_lpt_scan_callback)scan_check_cb,
+				    &lst);
+	if (err && err != -ENOSPC)
+		goto out;
+
+	if (lst.empty_lebs != c->lst.empty_lebs ||
+	    lst.idx_lebs != c->lst.idx_lebs ||
+	    lst.total_free != c->lst.total_free ||
+	    lst.total_dirty != c->lst.total_dirty ||
+	    lst.total_used != c->lst.total_used) {
+		ubifs_err(c, "bad overall accounting");
+		ubifs_err(c, "calculated: empty_lebs %d, idx_lebs %d, total_free %lld, total_dirty %lld, total_used %lld",
+			  lst.empty_lebs, lst.idx_lebs, lst.total_free,
+			  lst.total_dirty, lst.total_used);
+		ubifs_err(c, "read from lprops: empty_lebs %d, idx_lebs %d, total_free %lld, total_dirty %lld, total_used %lld",
+			  c->lst.empty_lebs, c->lst.idx_lebs, c->lst.total_free,
+			  c->lst.total_dirty, c->lst.total_used);
+		err = -EINVAL;
+		goto out;
+	}
+
+	if (lst.total_dead != c->lst.total_dead ||
+	    lst.total_dark != c->lst.total_dark) {
+		ubifs_err(c, "bad dead/dark space accounting");
+		ubifs_err(c, "calculated: total_dead %lld, total_dark %lld",
+			  lst.total_dead, lst.total_dark);
+		ubifs_err(c, "read from lprops: total_dead %lld, total_dark %lld",
+			  c->lst.total_dead, c->lst.total_dark);
+		err = -EINVAL;
+		goto out;
+	}
+
+	err = dbg_check_cats(c);
+out:
+	return err;
+}
diff --git a/ubifs-utils/libubifs/lpt.c b/ubifs-utils/libubifs/lpt.c
new file mode 100644
index 00000000..1889170b
--- /dev/null
+++ b/ubifs-utils/libubifs/lpt.c
@@ -0,0 +1,2451 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file implements the LEB properties tree (LPT) area. The LPT area
+ * contains the LEB properties tree, a table of LPT area eraseblocks (ltab), and
+ * (for the "big" model) a table of saved LEB numbers (lsave). The LPT area sits
+ * between the log and the orphan area.
+ *
+ * The LPT area is like a miniature self-contained file system. It is required
+ * that it never runs out of space, is fast to access and update, and scales
+ * logarithmically. The LEB properties tree is implemented as a wandering tree
+ * much like the TNC, and the LPT area has its own garbage collection.
+ *
+ * The LPT has two slightly different forms called the "small model" and the
+ * "big model". The small model is used when the entire LEB properties table
+ * can be written into a single eraseblock. In that case, garbage collection
+ * consists of just writing the whole table, which therefore makes all other
+ * eraseblocks reusable. In the case of the big model, dirty eraseblocks are
+ * selected for garbage collection, which consists of marking the clean nodes in
+ * that LEB as dirty, and then only the dirty nodes are written out. Also, in
+ * the case of the big model, a table of LEB numbers is saved so that the entire
+ * LPT does not to be scanned looking for empty eraseblocks when UBIFS is first
+ * mounted.
+ */
+
+#include "ubifs.h"
+#include <linux/crc16.h>
+#include <linux/math64.h>
+#include <linux/slab.h>
+
+/**
+ * do_calc_lpt_geom - calculate sizes for the LPT area.
+ * @c: the UBIFS file-system description object
+ *
+ * Calculate the sizes of LPT bit fields, nodes, and tree, based on the
+ * properties of the flash and whether LPT is "big" (c->big_lpt).
+ */
+static void do_calc_lpt_geom(struct ubifs_info *c)
+{
+	int i, n, bits, per_leb_wastage, max_pnode_cnt;
+	long long sz, tot_wastage;
+
+	n = c->main_lebs + c->max_leb_cnt - c->leb_cnt;
+	max_pnode_cnt = DIV_ROUND_UP(n, UBIFS_LPT_FANOUT);
+
+	c->lpt_hght = 1;
+	n = UBIFS_LPT_FANOUT;
+	while (n < max_pnode_cnt) {
+		c->lpt_hght += 1;
+		n <<= UBIFS_LPT_FANOUT_SHIFT;
+	}
+
+	c->pnode_cnt = DIV_ROUND_UP(c->main_lebs, UBIFS_LPT_FANOUT);
+
+	n = DIV_ROUND_UP(c->pnode_cnt, UBIFS_LPT_FANOUT);
+	c->nnode_cnt = n;
+	for (i = 1; i < c->lpt_hght; i++) {
+		n = DIV_ROUND_UP(n, UBIFS_LPT_FANOUT);
+		c->nnode_cnt += n;
+	}
+
+	c->space_bits = fls(c->leb_size) - 3;
+	c->lpt_lnum_bits = fls(c->lpt_lebs);
+	c->lpt_offs_bits = fls(c->leb_size - 1);
+	c->lpt_spc_bits = fls(c->leb_size);
+
+	n = DIV_ROUND_UP(c->max_leb_cnt, UBIFS_LPT_FANOUT);
+	c->pcnt_bits = fls(n - 1);
+
+	c->lnum_bits = fls(c->max_leb_cnt - 1);
+
+	bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
+	       (c->big_lpt ? c->pcnt_bits : 0) +
+	       (c->space_bits * 2 + 1) * UBIFS_LPT_FANOUT;
+	c->pnode_sz = (bits + 7) / 8;
+
+	bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
+	       (c->big_lpt ? c->pcnt_bits : 0) +
+	       (c->lpt_lnum_bits + c->lpt_offs_bits) * UBIFS_LPT_FANOUT;
+	c->nnode_sz = (bits + 7) / 8;
+
+	bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
+	       c->lpt_lebs * c->lpt_spc_bits * 2;
+	c->ltab_sz = (bits + 7) / 8;
+
+	bits = UBIFS_LPT_CRC_BITS + UBIFS_LPT_TYPE_BITS +
+	       c->lnum_bits * c->lsave_cnt;
+	c->lsave_sz = (bits + 7) / 8;
+
+	/* Calculate the minimum LPT size */
+	c->lpt_sz = (long long)c->pnode_cnt * c->pnode_sz;
+	c->lpt_sz += (long long)c->nnode_cnt * c->nnode_sz;
+	c->lpt_sz += c->ltab_sz;
+	if (c->big_lpt)
+		c->lpt_sz += c->lsave_sz;
+
+	/* Add wastage */
+	sz = c->lpt_sz;
+	per_leb_wastage = max_t(int, c->pnode_sz, c->nnode_sz);
+	sz += per_leb_wastage;
+	tot_wastage = per_leb_wastage;
+	while (sz > c->leb_size) {
+		sz += per_leb_wastage;
+		sz -= c->leb_size;
+		tot_wastage += per_leb_wastage;
+	}
+	tot_wastage += ALIGN(sz, c->min_io_size) - sz;
+	c->lpt_sz += tot_wastage;
+}
+
+/**
+ * ubifs_calc_lpt_geom - calculate and check sizes for the LPT area.
+ * @c: the UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_calc_lpt_geom(struct ubifs_info *c)
+{
+	int lebs_needed;
+	long long sz;
+
+	do_calc_lpt_geom(c);
+
+	/* Verify that lpt_lebs is big enough */
+	sz = c->lpt_sz * 2; /* Must have at least 2 times the size */
+	lebs_needed = div_u64(sz + c->leb_size - 1, c->leb_size);
+	if (lebs_needed > c->lpt_lebs) {
+		ubifs_err(c, "too few LPT LEBs");
+		return -EINVAL;
+	}
+
+	/* Verify that ltab fits in a single LEB (since ltab is a single node */
+	if (c->ltab_sz > c->leb_size) {
+		ubifs_err(c, "LPT ltab too big");
+		return -EINVAL;
+	}
+
+	c->check_lpt_free = c->big_lpt;
+	return 0;
+}
+
+/**
+ * calc_dflt_lpt_geom - calculate default LPT geometry.
+ * @c: the UBIFS file-system description object
+ * @main_lebs: number of main area LEBs is passed and returned here
+ * @big_lpt: whether the LPT area is "big" is returned here
+ *
+ * The size of the LPT area depends on parameters that themselves are dependent
+ * on the size of the LPT area. This function, successively recalculates the LPT
+ * area geometry until the parameters and resultant geometry are consistent.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int calc_dflt_lpt_geom(struct ubifs_info *c, int *main_lebs,
+			      int *big_lpt)
+{
+	int i, lebs_needed;
+	long long sz;
+
+	/* Start by assuming the minimum number of LPT LEBs */
+	c->lpt_lebs = UBIFS_MIN_LPT_LEBS;
+	c->main_lebs = *main_lebs - c->lpt_lebs;
+	if (c->main_lebs <= 0)
+		return -EINVAL;
+
+	/* And assume we will use the small LPT model */
+	c->big_lpt = 0;
+
+	/*
+	 * Calculate the geometry based on assumptions above and then see if it
+	 * makes sense
+	 */
+	do_calc_lpt_geom(c);
+
+	/* Small LPT model must have lpt_sz < leb_size */
+	if (c->lpt_sz > c->leb_size) {
+		/* Nope, so try again using big LPT model */
+		c->big_lpt = 1;
+		do_calc_lpt_geom(c);
+	}
+
+	/* Now check there are enough LPT LEBs */
+	for (i = 0; i < 64 ; i++) {
+		sz = c->lpt_sz * 4; /* Allow 4 times the size */
+		lebs_needed = div_u64(sz + c->leb_size - 1, c->leb_size);
+		if (lebs_needed > c->lpt_lebs) {
+			/* Not enough LPT LEBs so try again with more */
+			c->lpt_lebs = lebs_needed;
+			c->main_lebs = *main_lebs - c->lpt_lebs;
+			if (c->main_lebs <= 0)
+				return -EINVAL;
+			do_calc_lpt_geom(c);
+			continue;
+		}
+		if (c->ltab_sz > c->leb_size) {
+			ubifs_err(c, "LPT ltab too big");
+			return -EINVAL;
+		}
+		*main_lebs = c->main_lebs;
+		*big_lpt = c->big_lpt;
+		return 0;
+	}
+	return -EINVAL;
+}
+
+/**
+ * pack_bits - pack bit fields end-to-end.
+ * @c: UBIFS file-system description object
+ * @addr: address at which to pack (passed and next address returned)
+ * @pos: bit position at which to pack (passed and next position returned)
+ * @val: value to pack
+ * @nrbits: number of bits of value to pack (1-32)
+ */
+static void pack_bits(const struct ubifs_info *c, uint8_t **addr, int *pos, uint32_t val, int nrbits)
+{
+	uint8_t *p = *addr;
+	int b = *pos;
+
+	ubifs_assert(c, nrbits > 0);
+	ubifs_assert(c, nrbits <= 32);
+	ubifs_assert(c, *pos >= 0);
+	ubifs_assert(c, *pos < 8);
+	ubifs_assert(c, (val >> nrbits) == 0 || nrbits == 32);
+	if (b) {
+		*p |= ((uint8_t)val) << b;
+		nrbits += b;
+		if (nrbits > 8) {
+			*++p = (uint8_t)(val >>= (8 - b));
+			if (nrbits > 16) {
+				*++p = (uint8_t)(val >>= 8);
+				if (nrbits > 24) {
+					*++p = (uint8_t)(val >>= 8);
+					if (nrbits > 32)
+						*++p = (uint8_t)(val >>= 8);
+				}
+			}
+		}
+	} else {
+		*p = (uint8_t)val;
+		if (nrbits > 8) {
+			*++p = (uint8_t)(val >>= 8);
+			if (nrbits > 16) {
+				*++p = (uint8_t)(val >>= 8);
+				if (nrbits > 24)
+					*++p = (uint8_t)(val >>= 8);
+			}
+		}
+	}
+	b = nrbits & 7;
+	if (b == 0)
+		p++;
+	*addr = p;
+	*pos = b;
+}
+
+/**
+ * ubifs_unpack_bits - unpack bit fields.
+ * @c: UBIFS file-system description object
+ * @addr: address at which to unpack (passed and next address returned)
+ * @pos: bit position at which to unpack (passed and next position returned)
+ * @nrbits: number of bits of value to unpack (1-32)
+ *
+ * This functions returns the value unpacked.
+ */
+uint32_t ubifs_unpack_bits(const struct ubifs_info *c, uint8_t **addr, int *pos, int nrbits)
+{
+	const int k = 32 - nrbits;
+	uint8_t *p = *addr;
+	int b = *pos;
+	uint32_t val;
+	const int bytes = (nrbits + b + 7) >> 3;
+
+	ubifs_assert(c, nrbits > 0);
+	ubifs_assert(c, nrbits <= 32);
+	ubifs_assert(c, *pos >= 0);
+	ubifs_assert(c, *pos < 8);
+	if (b) {
+		switch (bytes) {
+		case 2:
+			val = p[1];
+			break;
+		case 3:
+			val = p[1] | ((uint32_t)p[2] << 8);
+			break;
+		case 4:
+			val = p[1] | ((uint32_t)p[2] << 8) |
+				     ((uint32_t)p[3] << 16);
+			break;
+		case 5:
+			val = p[1] | ((uint32_t)p[2] << 8) |
+				     ((uint32_t)p[3] << 16) |
+				     ((uint32_t)p[4] << 24);
+		}
+		val <<= (8 - b);
+		val |= *p >> b;
+		nrbits += b;
+	} else {
+		switch (bytes) {
+		case 1:
+			val = p[0];
+			break;
+		case 2:
+			val = p[0] | ((uint32_t)p[1] << 8);
+			break;
+		case 3:
+			val = p[0] | ((uint32_t)p[1] << 8) |
+				     ((uint32_t)p[2] << 16);
+			break;
+		case 4:
+			val = p[0] | ((uint32_t)p[1] << 8) |
+				     ((uint32_t)p[2] << 16) |
+				     ((uint32_t)p[3] << 24);
+			break;
+		}
+	}
+	val <<= k;
+	val >>= k;
+	b = nrbits & 7;
+	p += nrbits >> 3;
+	*addr = p;
+	*pos = b;
+	ubifs_assert(c, (val >> nrbits) == 0 || nrbits - b == 32);
+	return val;
+}
+
+/**
+ * ubifs_pack_pnode - pack all the bit fields of a pnode.
+ * @c: UBIFS file-system description object
+ * @buf: buffer into which to pack
+ * @pnode: pnode to pack
+ */
+void ubifs_pack_pnode(struct ubifs_info *c, void *buf,
+		      struct ubifs_pnode *pnode)
+{
+	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
+	int i, pos = 0;
+	uint16_t crc;
+
+	pack_bits(c, &addr, &pos, UBIFS_LPT_PNODE, UBIFS_LPT_TYPE_BITS);
+	if (c->big_lpt)
+		pack_bits(c, &addr, &pos, pnode->num, c->pcnt_bits);
+	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+		pack_bits(c, &addr, &pos, pnode->lprops[i].free >> 3,
+			  c->space_bits);
+		pack_bits(c, &addr, &pos, pnode->lprops[i].dirty >> 3,
+			  c->space_bits);
+		if (pnode->lprops[i].flags & LPROPS_INDEX)
+			pack_bits(c, &addr, &pos, 1, 1);
+		else
+			pack_bits(c, &addr, &pos, 0, 1);
+	}
+	crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
+		    c->pnode_sz - UBIFS_LPT_CRC_BYTES);
+	addr = buf;
+	pos = 0;
+	pack_bits(c, &addr, &pos, crc, UBIFS_LPT_CRC_BITS);
+}
+
+/**
+ * ubifs_pack_nnode - pack all the bit fields of a nnode.
+ * @c: UBIFS file-system description object
+ * @buf: buffer into which to pack
+ * @nnode: nnode to pack
+ */
+void ubifs_pack_nnode(struct ubifs_info *c, void *buf,
+		      struct ubifs_nnode *nnode)
+{
+	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
+	int i, pos = 0;
+	uint16_t crc;
+
+	pack_bits(c, &addr, &pos, UBIFS_LPT_NNODE, UBIFS_LPT_TYPE_BITS);
+	if (c->big_lpt)
+		pack_bits(c, &addr, &pos, nnode->num, c->pcnt_bits);
+	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+		int lnum = nnode->nbranch[i].lnum;
+
+		if (lnum == 0)
+			lnum = c->lpt_last + 1;
+		pack_bits(c, &addr, &pos, lnum - c->lpt_first, c->lpt_lnum_bits);
+		pack_bits(c, &addr, &pos, nnode->nbranch[i].offs,
+			  c->lpt_offs_bits);
+	}
+	crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
+		    c->nnode_sz - UBIFS_LPT_CRC_BYTES);
+	addr = buf;
+	pos = 0;
+	pack_bits(c, &addr, &pos, crc, UBIFS_LPT_CRC_BITS);
+}
+
+/**
+ * ubifs_pack_ltab - pack the LPT's own lprops table.
+ * @c: UBIFS file-system description object
+ * @buf: buffer into which to pack
+ * @ltab: LPT's own lprops table to pack
+ */
+void ubifs_pack_ltab(struct ubifs_info *c, void *buf,
+		     struct ubifs_lpt_lprops *ltab)
+{
+	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
+	int i, pos = 0;
+	uint16_t crc;
+
+	pack_bits(c, &addr, &pos, UBIFS_LPT_LTAB, UBIFS_LPT_TYPE_BITS);
+	for (i = 0; i < c->lpt_lebs; i++) {
+		pack_bits(c, &addr, &pos, ltab[i].free, c->lpt_spc_bits);
+		pack_bits(c, &addr, &pos, ltab[i].dirty, c->lpt_spc_bits);
+	}
+	crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
+		    c->ltab_sz - UBIFS_LPT_CRC_BYTES);
+	addr = buf;
+	pos = 0;
+	pack_bits(c, &addr, &pos, crc, UBIFS_LPT_CRC_BITS);
+}
+
+/**
+ * ubifs_pack_lsave - pack the LPT's save table.
+ * @c: UBIFS file-system description object
+ * @buf: buffer into which to pack
+ * @lsave: LPT's save table to pack
+ */
+void ubifs_pack_lsave(struct ubifs_info *c, void *buf, int *lsave)
+{
+	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
+	int i, pos = 0;
+	uint16_t crc;
+
+	pack_bits(c, &addr, &pos, UBIFS_LPT_LSAVE, UBIFS_LPT_TYPE_BITS);
+	for (i = 0; i < c->lsave_cnt; i++)
+		pack_bits(c, &addr, &pos, lsave[i], c->lnum_bits);
+	crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
+		    c->lsave_sz - UBIFS_LPT_CRC_BYTES);
+	addr = buf;
+	pos = 0;
+	pack_bits(c, &addr, &pos, crc, UBIFS_LPT_CRC_BITS);
+}
+
+/**
+ * ubifs_add_lpt_dirt - add dirty space to LPT LEB properties.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number to which to add dirty space
+ * @dirty: amount of dirty space to add
+ */
+void ubifs_add_lpt_dirt(struct ubifs_info *c, int lnum, int dirty)
+{
+	if (!dirty || !lnum)
+		return;
+	dbg_lp("LEB %d add %d to %d",
+	       lnum, dirty, c->ltab[lnum - c->lpt_first].dirty);
+	ubifs_assert(c, lnum >= c->lpt_first && lnum <= c->lpt_last);
+	c->ltab[lnum - c->lpt_first].dirty += dirty;
+}
+
+/**
+ * set_ltab - set LPT LEB properties.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number
+ * @free: amount of free space
+ * @dirty: amount of dirty space
+ */
+static void set_ltab(struct ubifs_info *c, int lnum, int free, int dirty)
+{
+	dbg_lp("LEB %d free %d dirty %d to %d %d",
+	       lnum, c->ltab[lnum - c->lpt_first].free,
+	       c->ltab[lnum - c->lpt_first].dirty, free, dirty);
+	ubifs_assert(c, lnum >= c->lpt_first && lnum <= c->lpt_last);
+	c->ltab[lnum - c->lpt_first].free = free;
+	c->ltab[lnum - c->lpt_first].dirty = dirty;
+}
+
+/**
+ * ubifs_add_nnode_dirt - add dirty space to LPT LEB properties.
+ * @c: UBIFS file-system description object
+ * @nnode: nnode for which to add dirt
+ */
+void ubifs_add_nnode_dirt(struct ubifs_info *c, struct ubifs_nnode *nnode)
+{
+	struct ubifs_nnode *np = nnode->parent;
+
+	if (np)
+		ubifs_add_lpt_dirt(c, np->nbranch[nnode->iip].lnum,
+				   c->nnode_sz);
+	else {
+		ubifs_add_lpt_dirt(c, c->lpt_lnum, c->nnode_sz);
+		if (!(c->lpt_drty_flgs & LTAB_DIRTY)) {
+			c->lpt_drty_flgs |= LTAB_DIRTY;
+			ubifs_add_lpt_dirt(c, c->ltab_lnum, c->ltab_sz);
+		}
+	}
+}
+
+/**
+ * add_pnode_dirt - add dirty space to LPT LEB properties.
+ * @c: UBIFS file-system description object
+ * @pnode: pnode for which to add dirt
+ */
+static void add_pnode_dirt(struct ubifs_info *c, struct ubifs_pnode *pnode)
+{
+	ubifs_add_lpt_dirt(c, pnode->parent->nbranch[pnode->iip].lnum,
+			   c->pnode_sz);
+}
+
+/**
+ * calc_nnode_num - calculate nnode number.
+ * @row: the row in the tree (root is zero)
+ * @col: the column in the row (leftmost is zero)
+ *
+ * The nnode number is a number that uniquely identifies a nnode and can be used
+ * easily to traverse the tree from the root to that nnode.
+ *
+ * This function calculates and returns the nnode number for the nnode at @row
+ * and @col.
+ */
+static int calc_nnode_num(int row, int col)
+{
+	int num, bits;
+
+	num = 1;
+	while (row--) {
+		bits = (col & (UBIFS_LPT_FANOUT - 1));
+		col >>= UBIFS_LPT_FANOUT_SHIFT;
+		num <<= UBIFS_LPT_FANOUT_SHIFT;
+		num |= bits;
+	}
+	return num;
+}
+
+/**
+ * calc_nnode_num_from_parent - calculate nnode number.
+ * @c: UBIFS file-system description object
+ * @parent: parent nnode
+ * @iip: index in parent
+ *
+ * The nnode number is a number that uniquely identifies a nnode and can be used
+ * easily to traverse the tree from the root to that nnode.
+ *
+ * This function calculates and returns the nnode number based on the parent's
+ * nnode number and the index in parent.
+ */
+static int calc_nnode_num_from_parent(const struct ubifs_info *c,
+				      struct ubifs_nnode *parent, int iip)
+{
+	int num, shft;
+
+	if (!parent)
+		return 1;
+	shft = (c->lpt_hght - parent->level) * UBIFS_LPT_FANOUT_SHIFT;
+	num = parent->num ^ (1 << shft);
+	num |= (UBIFS_LPT_FANOUT + iip) << shft;
+	return num;
+}
+
+/**
+ * calc_pnode_num_from_parent - calculate pnode number.
+ * @c: UBIFS file-system description object
+ * @parent: parent nnode
+ * @iip: index in parent
+ *
+ * The pnode number is a number that uniquely identifies a pnode and can be used
+ * easily to traverse the tree from the root to that pnode.
+ *
+ * This function calculates and returns the pnode number based on the parent's
+ * nnode number and the index in parent.
+ */
+static int calc_pnode_num_from_parent(const struct ubifs_info *c,
+				      struct ubifs_nnode *parent, int iip)
+{
+	int i, n = c->lpt_hght - 1, pnum = parent->num, num = 0;
+
+	for (i = 0; i < n; i++) {
+		num <<= UBIFS_LPT_FANOUT_SHIFT;
+		num |= pnum & (UBIFS_LPT_FANOUT - 1);
+		pnum >>= UBIFS_LPT_FANOUT_SHIFT;
+	}
+	num <<= UBIFS_LPT_FANOUT_SHIFT;
+	num |= iip;
+	return num;
+}
+
+/**
+ * ubifs_create_lpt - create lpt acccording to lprops array.
+ * @c: UBIFS file-system description object
+ * @lps: array of logical eraseblock properties
+ * @lp_cnt: the length of @lps
+ * @hash: hash of the LPT is returned here
+ *
+ * This function creates lpt, the pnode will be initialized based on
+ * corresponding elements in @lps. If there are no corresponding lprops
+ * (eg. @lp_cnt is smaller than @c->main_lebs), the LEB property is set
+ * as free state.
+ */
+int ubifs_create_lpt(struct ubifs_info *c, struct ubifs_lprops *lps, int lp_cnt,
+		     u8 *hash)
+{
+	int lnum, err = 0, i, j, cnt, len, alen, row;
+	int blnum, boffs, bsz, bcnt;
+	struct ubifs_pnode *pnode = NULL;
+	struct ubifs_nnode *nnode = NULL;
+	void *buf = NULL, *p;
+	struct ubifs_lpt_lprops *ltab = NULL;
+	int *lsave = NULL;
+	struct shash_desc *desc;
+
+	desc = ubifs_hash_get_desc(c);
+	if (IS_ERR(desc))
+		return PTR_ERR(desc);
+
+	lsave = kmalloc_array(c->lsave_cnt, sizeof(int), GFP_KERNEL);
+	pnode = kzalloc(sizeof(struct ubifs_pnode), GFP_KERNEL);
+	nnode = kzalloc(sizeof(struct ubifs_nnode), GFP_KERNEL);
+	buf = vmalloc(c->leb_size);
+	ltab = vmalloc(array_size(sizeof(struct ubifs_lpt_lprops),
+				  c->lpt_lebs));
+	if (!pnode || !nnode || !buf || !ltab || !lsave) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	ubifs_assert(c, !c->ltab);
+	c->ltab = ltab; /* Needed by set_ltab */
+
+	/* Initialize LPT's own lprops */
+	for (i = 0; i < c->lpt_lebs; i++) {
+		ltab[i].free = c->leb_size;
+		ltab[i].dirty = 0;
+		ltab[i].tgc = 0;
+		ltab[i].cmt = 0;
+	}
+
+	lnum = c->lpt_first;
+	p = buf;
+	len = 0;
+	/* Number of leaf nodes (pnodes) */
+	cnt = c->pnode_cnt;
+
+	/*
+	 * To calculate the internal node branches, we keep information about
+	 * the level below.
+	 */
+	blnum = lnum; /* LEB number of level below */
+	boffs = 0; /* Offset of level below */
+	bcnt = cnt; /* Number of nodes in level below */
+	bsz = c->pnode_sz; /* Size of nodes in level below */
+
+	/* Add all pnodes */
+	for (i = 0; i < cnt; i++) {
+		if (len + c->pnode_sz > c->leb_size) {
+			alen = ALIGN(len, c->min_io_size);
+			set_ltab(c, lnum, c->leb_size - alen, alen - len);
+			memset(p, 0xff, alen - len);
+			err = ubifs_leb_change(c, lnum++, buf, alen);
+			if (err)
+				goto out;
+			p = buf;
+			len = 0;
+		}
+		/* Fill in the pnode */
+		for (j = 0; j < UBIFS_LPT_FANOUT; j++) {
+			int k = (i << UBIFS_LPT_FANOUT_SHIFT) + j;
+
+			if (k < lp_cnt) {
+				pnode->lprops[j].free = lps[k].free;
+				pnode->lprops[j].dirty = lps[k].dirty;
+				pnode->lprops[j].flags = lps[k].flags;
+			} else {
+				pnode->lprops[j].free = c->leb_size;
+				pnode->lprops[j].dirty = 0;
+				pnode->lprops[j].flags = 0;
+			}
+		}
+		ubifs_pack_pnode(c, p, pnode);
+		err = ubifs_shash_update(c, desc, p, c->pnode_sz);
+		if (err)
+			goto out;
+
+		p += c->pnode_sz;
+		len += c->pnode_sz;
+		/*
+		 * pnodes are simply numbered left to right starting at zero,
+		 * which means the pnode number can be used easily to traverse
+		 * down the tree to the corresponding pnode.
+		 */
+		pnode->num += 1;
+	}
+
+	row = 0;
+	for (i = UBIFS_LPT_FANOUT; cnt > i; i <<= UBIFS_LPT_FANOUT_SHIFT)
+		row += 1;
+	/* Add all nnodes, one level at a time */
+	while (1) {
+		/* Number of internal nodes (nnodes) at next level */
+		cnt = DIV_ROUND_UP(cnt, UBIFS_LPT_FANOUT);
+		for (i = 0; i < cnt; i++) {
+			if (len + c->nnode_sz > c->leb_size) {
+				alen = ALIGN(len, c->min_io_size);
+				set_ltab(c, lnum, c->leb_size - alen,
+					    alen - len);
+				memset(p, 0xff, alen - len);
+				err = ubifs_leb_change(c, lnum++, buf, alen);
+				if (err)
+					goto out;
+				p = buf;
+				len = 0;
+			}
+			/* Only 1 nnode at this level, so it is the root */
+			if (cnt == 1) {
+				c->lpt_lnum = lnum;
+				c->lpt_offs = len;
+			}
+			/* Set branches to the level below */
+			for (j = 0; j < UBIFS_LPT_FANOUT; j++) {
+				if (bcnt) {
+					if (boffs + bsz > c->leb_size) {
+						blnum += 1;
+						boffs = 0;
+					}
+					nnode->nbranch[j].lnum = blnum;
+					nnode->nbranch[j].offs = boffs;
+					boffs += bsz;
+					bcnt--;
+				} else {
+					nnode->nbranch[j].lnum = 0;
+					nnode->nbranch[j].offs = 0;
+				}
+			}
+			nnode->num = calc_nnode_num(row, i);
+			ubifs_pack_nnode(c, p, nnode);
+			p += c->nnode_sz;
+			len += c->nnode_sz;
+		}
+		/* Only 1 nnode at this level, so it is the root */
+		if (cnt == 1)
+			break;
+		/* Update the information about the level below */
+		bcnt = cnt;
+		bsz = c->nnode_sz;
+		row -= 1;
+	}
+
+	if (c->big_lpt) {
+		/* Need to add LPT's save table */
+		if (len + c->lsave_sz > c->leb_size) {
+			alen = ALIGN(len, c->min_io_size);
+			set_ltab(c, lnum, c->leb_size - alen, alen - len);
+			memset(p, 0xff, alen - len);
+			err = ubifs_leb_change(c, lnum++, buf, alen);
+			if (err)
+				goto out;
+			p = buf;
+			len = 0;
+		}
+
+		c->lsave_lnum = lnum;
+		c->lsave_offs = len;
+
+		for (i = 0; i < c->lsave_cnt && i < c->main_lebs; i++)
+			lsave[i] = c->main_first + i;
+		for (; i < c->lsave_cnt; i++)
+			lsave[i] = c->main_first;
+
+		ubifs_pack_lsave(c, p, lsave);
+		p += c->lsave_sz;
+		len += c->lsave_sz;
+	}
+
+	/* Need to add LPT's own LEB properties table */
+	if (len + c->ltab_sz > c->leb_size) {
+		alen = ALIGN(len, c->min_io_size);
+		set_ltab(c, lnum, c->leb_size - alen, alen - len);
+		memset(p, 0xff, alen - len);
+		err = ubifs_leb_change(c, lnum++, buf, alen);
+		if (err)
+			goto out;
+		p = buf;
+		len = 0;
+	}
+
+	c->ltab_lnum = lnum;
+	c->ltab_offs = len;
+
+	/* Update ltab before packing it */
+	len += c->ltab_sz;
+	alen = ALIGN(len, c->min_io_size);
+	set_ltab(c, lnum, c->leb_size - alen, alen - len);
+
+	ubifs_pack_ltab(c, p, ltab);
+	p += c->ltab_sz;
+
+	/* Write remaining buffer */
+	memset(p, 0xff, alen - len);
+	err = ubifs_leb_change(c, lnum, buf, alen);
+	if (err)
+		goto out;
+
+	err = ubifs_shash_final(c, desc, hash);
+	if (err)
+		goto out;
+
+	c->nhead_lnum = lnum;
+	c->nhead_offs = ALIGN(len, c->min_io_size);
+
+	dbg_lp("space_bits %d", c->space_bits);
+	dbg_lp("lpt_lnum_bits %d", c->lpt_lnum_bits);
+	dbg_lp("lpt_offs_bits %d", c->lpt_offs_bits);
+	dbg_lp("lpt_spc_bits %d", c->lpt_spc_bits);
+	dbg_lp("pcnt_bits %d", c->pcnt_bits);
+	dbg_lp("lnum_bits %d", c->lnum_bits);
+	dbg_lp("pnode_sz %d", c->pnode_sz);
+	dbg_lp("nnode_sz %d", c->nnode_sz);
+	dbg_lp("ltab_sz %d", c->ltab_sz);
+	dbg_lp("lsave_sz %d", c->lsave_sz);
+	dbg_lp("lsave_cnt %d", c->lsave_cnt);
+	dbg_lp("lpt_hght %d", c->lpt_hght);
+	dbg_lp("big_lpt %u", c->big_lpt);
+	dbg_lp("LPT root is at %d:%d", c->lpt_lnum, c->lpt_offs);
+	dbg_lp("LPT head is at %d:%d", c->nhead_lnum, c->nhead_offs);
+	dbg_lp("LPT ltab is at %d:%d", c->ltab_lnum, c->ltab_offs);
+	if (c->big_lpt)
+		dbg_lp("LPT lsave is at %d:%d", c->lsave_lnum, c->lsave_offs);
+out:
+	c->ltab = NULL;
+	kfree(desc);
+	kfree(lsave);
+	vfree(ltab);
+	vfree(buf);
+	kfree(nnode);
+	kfree(pnode);
+	return err;
+}
+
+/**
+ * ubifs_create_dflt_lpt - create default LPT.
+ * @c: UBIFS file-system description object
+ * @main_lebs: number of main area LEBs is passed and returned here
+ * @lpt_first: LEB number of first LPT LEB
+ * @lpt_lebs: number of LEBs for LPT is passed and returned here
+ * @big_lpt: use big LPT model is passed and returned here
+ * @hash: hash of the LPT is returned here
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_create_dflt_lpt(struct ubifs_info *c, int *main_lebs, int lpt_first,
+			  int *lpt_lebs, int *big_lpt, u8 *hash)
+{
+	int node_sz, iopos, err = 0;
+	struct ubifs_lprops lps[2];
+
+	err = calc_dflt_lpt_geom(c, main_lebs, big_lpt);
+	if (err)
+		return err;
+	*lpt_lebs = c->lpt_lebs;
+
+	/* Needed by 'ubifs_pack_nnode()' and 'set_ltab()' */
+	c->lpt_first = lpt_first;
+	/* Needed by 'set_ltab()' */
+	c->lpt_last = lpt_first + c->lpt_lebs - 1;
+	/* Needed by 'ubifs_pack_lsave()' */
+	c->main_first = c->leb_cnt - *main_lebs;
+
+	/*
+	 * The first pnode contains the LEB properties for the LEBs that contain
+	 * the root inode node and the root index node of the index tree.
+	 */
+	node_sz = ALIGN(ubifs_idx_node_sz(c, 1), 8);
+	iopos = ALIGN(node_sz, c->min_io_size);
+	lps[0].free = c->leb_size - iopos;
+	lps[0].dirty = iopos - node_sz;
+	lps[0].flags = LPROPS_INDEX;
+
+	node_sz = UBIFS_INO_NODE_SZ;
+	iopos = ALIGN(node_sz, c->min_io_size);
+	lps[1].free = c->leb_size - iopos;
+	lps[1].dirty = iopos - node_sz;
+	lps[1].flags = 0;
+
+	return ubifs_create_lpt(c, lps, 2, hash);
+}
+
+/**
+ * update_cats - add LEB properties of a pnode to LEB category lists and heaps.
+ * @c: UBIFS file-system description object
+ * @pnode: pnode
+ *
+ * When a pnode is loaded into memory, the LEB properties it contains are added,
+ * by this function, to the LEB category lists and heaps.
+ */
+static void update_cats(struct ubifs_info *c, struct ubifs_pnode *pnode)
+{
+	int i;
+
+	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+		int cat = pnode->lprops[i].flags & LPROPS_CAT_MASK;
+		int lnum = pnode->lprops[i].lnum;
+
+		if (!lnum)
+			return;
+		ubifs_add_to_cat(c, &pnode->lprops[i], cat);
+	}
+}
+
+/**
+ * replace_cats - add LEB properties of a pnode to LEB category lists and heaps.
+ * @c: UBIFS file-system description object
+ * @old_pnode: pnode copied
+ * @new_pnode: pnode copy
+ *
+ * During commit it is sometimes necessary to copy a pnode
+ * (see dirty_cow_pnode).  When that happens, references in
+ * category lists and heaps must be replaced.  This function does that.
+ */
+static void replace_cats(struct ubifs_info *c, struct ubifs_pnode *old_pnode,
+			 struct ubifs_pnode *new_pnode)
+{
+	int i;
+
+	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+		if (!new_pnode->lprops[i].lnum)
+			return;
+		ubifs_replace_cat(c, &old_pnode->lprops[i],
+				  &new_pnode->lprops[i]);
+	}
+}
+
+/**
+ * check_lpt_crc - check LPT node crc is correct.
+ * @c: UBIFS file-system description object
+ * @buf: buffer containing node
+ * @len: length of node
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int check_lpt_crc(const struct ubifs_info *c, void *buf, int len)
+{
+	int pos = 0;
+	uint8_t *addr = buf;
+	uint16_t crc, calc_crc;
+
+	crc = ubifs_unpack_bits(c, &addr, &pos, UBIFS_LPT_CRC_BITS);
+	calc_crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
+			 len - UBIFS_LPT_CRC_BYTES);
+	if (crc != calc_crc) {
+		ubifs_err(c, "invalid crc in LPT node: crc %hx calc %hx",
+			  crc, calc_crc);
+		dump_stack();
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/**
+ * check_lpt_type - check LPT node type is correct.
+ * @c: UBIFS file-system description object
+ * @addr: address of type bit field is passed and returned updated here
+ * @pos: position of type bit field is passed and returned updated here
+ * @type: expected type
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int check_lpt_type(const struct ubifs_info *c, uint8_t **addr,
+			  int *pos, int type)
+{
+	int node_type;
+
+	node_type = ubifs_unpack_bits(c, addr, pos, UBIFS_LPT_TYPE_BITS);
+	if (node_type != type) {
+		ubifs_err(c, "invalid type (%d) in LPT node type %d",
+			  node_type, type);
+		dump_stack();
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/**
+ * unpack_pnode - unpack a pnode.
+ * @c: UBIFS file-system description object
+ * @buf: buffer containing packed pnode to unpack
+ * @pnode: pnode structure to fill
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int unpack_pnode(const struct ubifs_info *c, void *buf,
+			struct ubifs_pnode *pnode)
+{
+	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
+	int i, pos = 0, err;
+
+	err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_PNODE);
+	if (err)
+		return err;
+	if (c->big_lpt)
+		pnode->num = ubifs_unpack_bits(c, &addr, &pos, c->pcnt_bits);
+	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+		struct ubifs_lprops * const lprops = &pnode->lprops[i];
+
+		lprops->free = ubifs_unpack_bits(c, &addr, &pos, c->space_bits);
+		lprops->free <<= 3;
+		lprops->dirty = ubifs_unpack_bits(c, &addr, &pos, c->space_bits);
+		lprops->dirty <<= 3;
+
+		if (ubifs_unpack_bits(c, &addr, &pos, 1))
+			lprops->flags = LPROPS_INDEX;
+		else
+			lprops->flags = 0;
+		lprops->flags |= ubifs_categorize_lprops(c, lprops);
+	}
+	err = check_lpt_crc(c, buf, c->pnode_sz);
+	return err;
+}
+
+/**
+ * ubifs_unpack_nnode - unpack a nnode.
+ * @c: UBIFS file-system description object
+ * @buf: buffer containing packed nnode to unpack
+ * @nnode: nnode structure to fill
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_unpack_nnode(const struct ubifs_info *c, void *buf,
+		       struct ubifs_nnode *nnode)
+{
+	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
+	int i, pos = 0, err;
+
+	err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_NNODE);
+	if (err)
+		return err;
+	if (c->big_lpt)
+		nnode->num = ubifs_unpack_bits(c, &addr, &pos, c->pcnt_bits);
+	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+		int lnum;
+
+		lnum = ubifs_unpack_bits(c, &addr, &pos, c->lpt_lnum_bits) +
+		       c->lpt_first;
+		if (lnum == c->lpt_last + 1)
+			lnum = 0;
+		nnode->nbranch[i].lnum = lnum;
+		nnode->nbranch[i].offs = ubifs_unpack_bits(c, &addr, &pos,
+						     c->lpt_offs_bits);
+	}
+	err = check_lpt_crc(c, buf, c->nnode_sz);
+	return err;
+}
+
+/**
+ * unpack_ltab - unpack the LPT's own lprops table.
+ * @c: UBIFS file-system description object
+ * @buf: buffer from which to unpack
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int unpack_ltab(const struct ubifs_info *c, void *buf)
+{
+	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
+	int i, pos = 0, err;
+
+	err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_LTAB);
+	if (err)
+		return err;
+	for (i = 0; i < c->lpt_lebs; i++) {
+		int free = ubifs_unpack_bits(c, &addr, &pos, c->lpt_spc_bits);
+		int dirty = ubifs_unpack_bits(c, &addr, &pos, c->lpt_spc_bits);
+
+		if (free < 0 || free > c->leb_size || dirty < 0 ||
+		    dirty > c->leb_size || free + dirty > c->leb_size)
+			return -EINVAL;
+
+		c->ltab[i].free = free;
+		c->ltab[i].dirty = dirty;
+		c->ltab[i].tgc = 0;
+		c->ltab[i].cmt = 0;
+	}
+	err = check_lpt_crc(c, buf, c->ltab_sz);
+	return err;
+}
+
+/**
+ * unpack_lsave - unpack the LPT's save table.
+ * @c: UBIFS file-system description object
+ * @buf: buffer from which to unpack
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int unpack_lsave(const struct ubifs_info *c, void *buf)
+{
+	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
+	int i, pos = 0, err;
+
+	err = check_lpt_type(c, &addr, &pos, UBIFS_LPT_LSAVE);
+	if (err)
+		return err;
+	for (i = 0; i < c->lsave_cnt; i++) {
+		int lnum = ubifs_unpack_bits(c, &addr, &pos, c->lnum_bits);
+
+		if (lnum < c->main_first || lnum >= c->leb_cnt)
+			return -EINVAL;
+		c->lsave[i] = lnum;
+	}
+	err = check_lpt_crc(c, buf, c->lsave_sz);
+	return err;
+}
+
+/**
+ * validate_nnode - validate a nnode.
+ * @c: UBIFS file-system description object
+ * @nnode: nnode to validate
+ * @parent: parent nnode (or NULL for the root nnode)
+ * @iip: index in parent
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int validate_nnode(const struct ubifs_info *c, struct ubifs_nnode *nnode,
+			  struct ubifs_nnode *parent, int iip)
+{
+	int i, lvl, max_offs;
+
+	if (c->big_lpt) {
+		int num = calc_nnode_num_from_parent(c, parent, iip);
+
+		if (nnode->num != num)
+			return -EINVAL;
+	}
+	lvl = parent ? parent->level - 1 : c->lpt_hght;
+	if (lvl < 1)
+		return -EINVAL;
+	if (lvl == 1)
+		max_offs = c->leb_size - c->pnode_sz;
+	else
+		max_offs = c->leb_size - c->nnode_sz;
+	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+		int lnum = nnode->nbranch[i].lnum;
+		int offs = nnode->nbranch[i].offs;
+
+		if (lnum == 0) {
+			if (offs != 0)
+				return -EINVAL;
+			continue;
+		}
+		if (lnum < c->lpt_first || lnum > c->lpt_last)
+			return -EINVAL;
+		if (offs < 0 || offs > max_offs)
+			return -EINVAL;
+	}
+	return 0;
+}
+
+/**
+ * validate_pnode - validate a pnode.
+ * @c: UBIFS file-system description object
+ * @pnode: pnode to validate
+ * @parent: parent nnode
+ * @iip: index in parent
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int validate_pnode(const struct ubifs_info *c, struct ubifs_pnode *pnode,
+			  struct ubifs_nnode *parent, int iip)
+{
+	int i;
+
+	if (c->big_lpt) {
+		int num = calc_pnode_num_from_parent(c, parent, iip);
+
+		if (pnode->num != num)
+			return -EINVAL;
+	}
+	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+		int free = pnode->lprops[i].free;
+		int dirty = pnode->lprops[i].dirty;
+
+		if (free < 0 || free > c->leb_size || free % c->min_io_size ||
+		    (free & 7))
+			return -EINVAL;
+		if (dirty < 0 || dirty > c->leb_size || (dirty & 7))
+			return -EINVAL;
+		if (dirty + free > c->leb_size)
+			return -EINVAL;
+	}
+	return 0;
+}
+
+/**
+ * set_pnode_lnum - set LEB numbers on a pnode.
+ * @c: UBIFS file-system description object
+ * @pnode: pnode to update
+ *
+ * This function calculates the LEB numbers for the LEB properties it contains
+ * based on the pnode number.
+ */
+static void set_pnode_lnum(const struct ubifs_info *c,
+			   struct ubifs_pnode *pnode)
+{
+	int i, lnum;
+
+	lnum = (pnode->num << UBIFS_LPT_FANOUT_SHIFT) + c->main_first;
+	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+		if (lnum >= c->leb_cnt)
+			return;
+		pnode->lprops[i].lnum = lnum++;
+	}
+}
+
+/**
+ * ubifs_read_nnode - read a nnode from flash and link it to the tree in memory.
+ * @c: UBIFS file-system description object
+ * @parent: parent nnode (or NULL for the root)
+ * @iip: index in parent
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_read_nnode(struct ubifs_info *c, struct ubifs_nnode *parent, int iip)
+{
+	struct ubifs_nbranch *branch = NULL;
+	struct ubifs_nnode *nnode = NULL;
+	void *buf = c->lpt_nod_buf;
+	int err, lnum, offs;
+
+	if (parent) {
+		branch = &parent->nbranch[iip];
+		lnum = branch->lnum;
+		offs = branch->offs;
+	} else {
+		lnum = c->lpt_lnum;
+		offs = c->lpt_offs;
+	}
+	nnode = kzalloc(sizeof(struct ubifs_nnode), GFP_NOFS);
+	if (!nnode) {
+		err = -ENOMEM;
+		goto out;
+	}
+	if (lnum == 0) {
+		/*
+		 * This nnode was not written which just means that the LEB
+		 * properties in the subtree below it describe empty LEBs. We
+		 * make the nnode as though we had read it, which in fact means
+		 * doing almost nothing.
+		 */
+		if (c->big_lpt)
+			nnode->num = calc_nnode_num_from_parent(c, parent, iip);
+	} else {
+		err = ubifs_leb_read(c, lnum, buf, offs, c->nnode_sz, 1);
+		if (err)
+			goto out;
+		err = ubifs_unpack_nnode(c, buf, nnode);
+		if (err)
+			goto out;
+	}
+	err = validate_nnode(c, nnode, parent, iip);
+	if (err)
+		goto out;
+	if (!c->big_lpt)
+		nnode->num = calc_nnode_num_from_parent(c, parent, iip);
+	if (parent) {
+		branch->nnode = nnode;
+		nnode->level = parent->level - 1;
+	} else {
+		c->nroot = nnode;
+		nnode->level = c->lpt_hght;
+	}
+	nnode->parent = parent;
+	nnode->iip = iip;
+	return 0;
+
+out:
+	ubifs_err(c, "error %d reading nnode at %d:%d", err, lnum, offs);
+	dump_stack();
+	kfree(nnode);
+	return err;
+}
+
+/**
+ * read_pnode - read a pnode from flash and link it to the tree in memory.
+ * @c: UBIFS file-system description object
+ * @parent: parent nnode
+ * @iip: index in parent
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int read_pnode(struct ubifs_info *c, struct ubifs_nnode *parent, int iip)
+{
+	struct ubifs_nbranch *branch;
+	struct ubifs_pnode *pnode = NULL;
+	void *buf = c->lpt_nod_buf;
+	int err, lnum, offs;
+
+	branch = &parent->nbranch[iip];
+	lnum = branch->lnum;
+	offs = branch->offs;
+	pnode = kzalloc(sizeof(struct ubifs_pnode), GFP_NOFS);
+	if (!pnode)
+		return -ENOMEM;
+
+	if (lnum == 0) {
+		/*
+		 * This pnode was not written which just means that the LEB
+		 * properties in it describe empty LEBs. We make the pnode as
+		 * though we had read it.
+		 */
+		int i;
+
+		if (c->big_lpt)
+			pnode->num = calc_pnode_num_from_parent(c, parent, iip);
+		for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+			struct ubifs_lprops * const lprops = &pnode->lprops[i];
+
+			lprops->free = c->leb_size;
+			lprops->flags = ubifs_categorize_lprops(c, lprops);
+		}
+	} else {
+		err = ubifs_leb_read(c, lnum, buf, offs, c->pnode_sz, 1);
+		if (err)
+			goto out;
+		err = unpack_pnode(c, buf, pnode);
+		if (err)
+			goto out;
+	}
+	err = validate_pnode(c, pnode, parent, iip);
+	if (err)
+		goto out;
+	if (!c->big_lpt)
+		pnode->num = calc_pnode_num_from_parent(c, parent, iip);
+	branch->pnode = pnode;
+	pnode->parent = parent;
+	pnode->iip = iip;
+	set_pnode_lnum(c, pnode);
+	c->pnodes_have += 1;
+	return 0;
+
+out:
+	ubifs_err(c, "error %d reading pnode at %d:%d", err, lnum, offs);
+	ubifs_dump_pnode(c, pnode, parent, iip);
+	dump_stack();
+	ubifs_err(c, "calc num: %d", calc_pnode_num_from_parent(c, parent, iip));
+	kfree(pnode);
+	return err;
+}
+
+/**
+ * read_ltab - read LPT's own lprops table.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int read_ltab(struct ubifs_info *c)
+{
+	int err;
+	void *buf;
+
+	buf = vmalloc(c->ltab_sz);
+	if (!buf)
+		return -ENOMEM;
+	err = ubifs_leb_read(c, c->ltab_lnum, buf, c->ltab_offs, c->ltab_sz, 1);
+	if (err)
+		goto out;
+	err = unpack_ltab(c, buf);
+out:
+	vfree(buf);
+	return err;
+}
+
+/**
+ * read_lsave - read LPT's save table.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int read_lsave(struct ubifs_info *c)
+{
+	int err, i;
+	void *buf;
+
+	buf = vmalloc(c->lsave_sz);
+	if (!buf)
+		return -ENOMEM;
+	err = ubifs_leb_read(c, c->lsave_lnum, buf, c->lsave_offs,
+			     c->lsave_sz, 1);
+	if (err)
+		goto out;
+	err = unpack_lsave(c, buf);
+	if (err)
+		goto out;
+	for (i = 0; i < c->lsave_cnt; i++) {
+		int lnum = c->lsave[i];
+		struct ubifs_lprops *lprops;
+
+		/*
+		 * Due to automatic resizing, the values in the lsave table
+		 * could be beyond the volume size - just ignore them.
+		 */
+		if (lnum >= c->leb_cnt)
+			continue;
+		lprops = ubifs_lpt_lookup(c, lnum);
+		if (IS_ERR(lprops)) {
+			err = PTR_ERR(lprops);
+			goto out;
+		}
+	}
+out:
+	vfree(buf);
+	return err;
+}
+
+/**
+ * ubifs_get_nnode - get a nnode.
+ * @c: UBIFS file-system description object
+ * @parent: parent nnode (or NULL for the root)
+ * @iip: index in parent
+ *
+ * This function returns a pointer to the nnode on success or a negative error
+ * code on failure.
+ */
+struct ubifs_nnode *ubifs_get_nnode(struct ubifs_info *c,
+				    struct ubifs_nnode *parent, int iip)
+{
+	struct ubifs_nbranch *branch;
+	struct ubifs_nnode *nnode;
+	int err;
+
+	branch = &parent->nbranch[iip];
+	nnode = branch->nnode;
+	if (nnode)
+		return nnode;
+	err = ubifs_read_nnode(c, parent, iip);
+	if (err)
+		return ERR_PTR(err);
+	return branch->nnode;
+}
+
+/**
+ * ubifs_get_pnode - get a pnode.
+ * @c: UBIFS file-system description object
+ * @parent: parent nnode
+ * @iip: index in parent
+ *
+ * This function returns a pointer to the pnode on success or a negative error
+ * code on failure.
+ */
+struct ubifs_pnode *ubifs_get_pnode(struct ubifs_info *c,
+				    struct ubifs_nnode *parent, int iip)
+{
+	struct ubifs_nbranch *branch;
+	struct ubifs_pnode *pnode;
+	int err;
+
+	branch = &parent->nbranch[iip];
+	pnode = branch->pnode;
+	if (pnode)
+		return pnode;
+	err = read_pnode(c, parent, iip);
+	if (err)
+		return ERR_PTR(err);
+	update_cats(c, branch->pnode);
+	return branch->pnode;
+}
+
+/**
+ * ubifs_pnode_lookup - lookup a pnode in the LPT.
+ * @c: UBIFS file-system description object
+ * @i: pnode number (0 to (main_lebs - 1) / UBIFS_LPT_FANOUT)
+ *
+ * This function returns a pointer to the pnode on success or a negative
+ * error code on failure.
+ */
+struct ubifs_pnode *ubifs_pnode_lookup(struct ubifs_info *c, int i)
+{
+	int err, h, iip, shft;
+	struct ubifs_nnode *nnode;
+
+	if (!c->nroot) {
+		err = ubifs_read_nnode(c, NULL, 0);
+		if (err)
+			return ERR_PTR(err);
+	}
+	i <<= UBIFS_LPT_FANOUT_SHIFT;
+	nnode = c->nroot;
+	shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
+	for (h = 1; h < c->lpt_hght; h++) {
+		iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
+		shft -= UBIFS_LPT_FANOUT_SHIFT;
+		nnode = ubifs_get_nnode(c, nnode, iip);
+		if (IS_ERR(nnode))
+			return ERR_CAST(nnode);
+	}
+	iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
+	return ubifs_get_pnode(c, nnode, iip);
+}
+
+/**
+ * ubifs_lpt_lookup - lookup LEB properties in the LPT.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number to lookup
+ *
+ * This function returns a pointer to the LEB properties on success or a
+ * negative error code on failure.
+ */
+struct ubifs_lprops *ubifs_lpt_lookup(struct ubifs_info *c, int lnum)
+{
+	int i, iip;
+	struct ubifs_pnode *pnode;
+
+	i = lnum - c->main_first;
+	pnode = ubifs_pnode_lookup(c, i >> UBIFS_LPT_FANOUT_SHIFT);
+	if (IS_ERR(pnode))
+		return ERR_CAST(pnode);
+	iip = (i & (UBIFS_LPT_FANOUT - 1));
+	dbg_lp("LEB %d, free %d, dirty %d, flags %d", lnum,
+	       pnode->lprops[iip].free, pnode->lprops[iip].dirty,
+	       pnode->lprops[iip].flags);
+	return &pnode->lprops[iip];
+}
+
+/**
+ * dirty_cow_nnode - ensure a nnode is not being committed.
+ * @c: UBIFS file-system description object
+ * @nnode: nnode to check
+ *
+ * Returns dirtied nnode on success or negative error code on failure.
+ */
+static struct ubifs_nnode *dirty_cow_nnode(struct ubifs_info *c,
+					   struct ubifs_nnode *nnode)
+{
+	struct ubifs_nnode *n;
+	int i;
+
+	if (!test_bit(COW_CNODE, &nnode->flags)) {
+		/* nnode is not being committed */
+		if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
+			c->dirty_nn_cnt += 1;
+			ubifs_add_nnode_dirt(c, nnode);
+		}
+		return nnode;
+	}
+
+	/* nnode is being committed, so copy it */
+	n = kmemdup(nnode, sizeof(struct ubifs_nnode), GFP_NOFS);
+	if (unlikely(!n))
+		return ERR_PTR(-ENOMEM);
+
+	n->cnext = NULL;
+	__set_bit(DIRTY_CNODE, &n->flags);
+	__clear_bit(COW_CNODE, &n->flags);
+
+	/* The children now have new parent */
+	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+		struct ubifs_nbranch *branch = &n->nbranch[i];
+
+		if (branch->cnode)
+			branch->cnode->parent = n;
+	}
+
+	ubifs_assert(c, !test_bit(OBSOLETE_CNODE, &nnode->flags));
+	__set_bit(OBSOLETE_CNODE, &nnode->flags);
+
+	c->dirty_nn_cnt += 1;
+	ubifs_add_nnode_dirt(c, nnode);
+	if (nnode->parent)
+		nnode->parent->nbranch[n->iip].nnode = n;
+	else
+		c->nroot = n;
+	return n;
+}
+
+/**
+ * dirty_cow_pnode - ensure a pnode is not being committed.
+ * @c: UBIFS file-system description object
+ * @pnode: pnode to check
+ *
+ * Returns dirtied pnode on success or negative error code on failure.
+ */
+static struct ubifs_pnode *dirty_cow_pnode(struct ubifs_info *c,
+					   struct ubifs_pnode *pnode)
+{
+	struct ubifs_pnode *p;
+
+	if (!test_bit(COW_CNODE, &pnode->flags)) {
+		/* pnode is not being committed */
+		if (!test_and_set_bit(DIRTY_CNODE, &pnode->flags)) {
+			c->dirty_pn_cnt += 1;
+			add_pnode_dirt(c, pnode);
+		}
+		return pnode;
+	}
+
+	/* pnode is being committed, so copy it */
+	p = kmemdup(pnode, sizeof(struct ubifs_pnode), GFP_NOFS);
+	if (unlikely(!p))
+		return ERR_PTR(-ENOMEM);
+
+	p->cnext = NULL;
+	__set_bit(DIRTY_CNODE, &p->flags);
+	__clear_bit(COW_CNODE, &p->flags);
+	replace_cats(c, pnode, p);
+
+	ubifs_assert(c, !test_bit(OBSOLETE_CNODE, &pnode->flags));
+	__set_bit(OBSOLETE_CNODE, &pnode->flags);
+
+	c->dirty_pn_cnt += 1;
+	add_pnode_dirt(c, pnode);
+	pnode->parent->nbranch[p->iip].pnode = p;
+	return p;
+}
+
+/**
+ * ubifs_lpt_lookup_dirty - lookup LEB properties in the LPT.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number to lookup
+ *
+ * This function returns a pointer to the LEB properties on success or a
+ * negative error code on failure.
+ */
+struct ubifs_lprops *ubifs_lpt_lookup_dirty(struct ubifs_info *c, int lnum)
+{
+	int err, i, h, iip, shft;
+	struct ubifs_nnode *nnode;
+	struct ubifs_pnode *pnode;
+
+	if (!c->nroot) {
+		err = ubifs_read_nnode(c, NULL, 0);
+		if (err)
+			return ERR_PTR(err);
+	}
+	nnode = c->nroot;
+	nnode = dirty_cow_nnode(c, nnode);
+	if (IS_ERR(nnode))
+		return ERR_CAST(nnode);
+	i = lnum - c->main_first;
+	shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
+	for (h = 1; h < c->lpt_hght; h++) {
+		iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
+		shft -= UBIFS_LPT_FANOUT_SHIFT;
+		nnode = ubifs_get_nnode(c, nnode, iip);
+		if (IS_ERR(nnode))
+			return ERR_CAST(nnode);
+		nnode = dirty_cow_nnode(c, nnode);
+		if (IS_ERR(nnode))
+			return ERR_CAST(nnode);
+	}
+	iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
+	pnode = ubifs_get_pnode(c, nnode, iip);
+	if (IS_ERR(pnode))
+		return ERR_CAST(pnode);
+	pnode = dirty_cow_pnode(c, pnode);
+	if (IS_ERR(pnode))
+		return ERR_CAST(pnode);
+	iip = (i & (UBIFS_LPT_FANOUT - 1));
+	dbg_lp("LEB %d, free %d, dirty %d, flags %d", lnum,
+	       pnode->lprops[iip].free, pnode->lprops[iip].dirty,
+	       pnode->lprops[iip].flags);
+	ubifs_assert(c, test_bit(DIRTY_CNODE, &pnode->flags));
+	return &pnode->lprops[iip];
+}
+
+/**
+ * ubifs_lpt_calc_hash - Calculate hash of the LPT pnodes
+ * @c: UBIFS file-system description object
+ * @hash: the returned hash of the LPT pnodes
+ *
+ * This function iterates over the LPT pnodes and creates a hash over them.
+ * Returns 0 for success or a negative error code otherwise.
+ */
+int ubifs_lpt_calc_hash(struct ubifs_info *c, u8 *hash)
+{
+	struct ubifs_nnode *nnode, *nn;
+	struct ubifs_cnode *cnode;
+	struct shash_desc *desc;
+	int iip = 0, i;
+	int bufsiz = max_t(int, c->nnode_sz, c->pnode_sz);
+	void *buf;
+	int err;
+
+	if (!ubifs_authenticated(c))
+		return 0;
+
+	if (!c->nroot) {
+		err = ubifs_read_nnode(c, NULL, 0);
+		if (err)
+			return err;
+	}
+
+	desc = ubifs_hash_get_desc(c);
+	if (IS_ERR(desc))
+		return PTR_ERR(desc);
+
+	buf = kmalloc(bufsiz, GFP_NOFS);
+	if (!buf) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	cnode = (struct ubifs_cnode *)c->nroot;
+
+	while (cnode) {
+		nnode = cnode->parent;
+		nn = (struct ubifs_nnode *)cnode;
+		if (cnode->level > 1) {
+			while (iip < UBIFS_LPT_FANOUT) {
+				if (nn->nbranch[iip].lnum == 0) {
+					/* Go right */
+					iip++;
+					continue;
+				}
+
+				nnode = ubifs_get_nnode(c, nn, iip);
+				if (IS_ERR(nnode)) {
+					err = PTR_ERR(nnode);
+					goto out;
+				}
+
+				/* Go down */
+				iip = 0;
+				cnode = (struct ubifs_cnode *)nnode;
+				break;
+			}
+			if (iip < UBIFS_LPT_FANOUT)
+				continue;
+		} else {
+			struct ubifs_pnode *pnode;
+
+			for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+				if (nn->nbranch[i].lnum == 0)
+					continue;
+				pnode = ubifs_get_pnode(c, nn, i);
+				if (IS_ERR(pnode)) {
+					err = PTR_ERR(pnode);
+					goto out;
+				}
+
+				ubifs_pack_pnode(c, buf, pnode);
+				err = ubifs_shash_update(c, desc, buf,
+							 c->pnode_sz);
+				if (err)
+					goto out;
+			}
+		}
+		/* Go up and to the right */
+		iip = cnode->iip + 1;
+		cnode = (struct ubifs_cnode *)nnode;
+	}
+
+	err = ubifs_shash_final(c, desc, hash);
+out:
+	kfree(desc);
+	kfree(buf);
+
+	return err;
+}
+
+/**
+ * lpt_check_hash - check the hash of the LPT.
+ * @c: UBIFS file-system description object
+ *
+ * This function calculates a hash over all pnodes in the LPT and compares it with
+ * the hash stored in the master node. Returns %0 on success and a negative error
+ * code on failure.
+ */
+static int lpt_check_hash(struct ubifs_info *c)
+{
+	int err;
+	u8 hash[UBIFS_HASH_ARR_SZ];
+
+	if (!ubifs_authenticated(c))
+		return 0;
+
+	err = ubifs_lpt_calc_hash(c, hash);
+	if (err)
+		return err;
+
+	if (ubifs_check_hash(c, c->mst_node->hash_lpt, hash)) {
+		err = -EPERM;
+		ubifs_err(c, "Failed to authenticate LPT");
+	} else {
+		err = 0;
+	}
+
+	return err;
+}
+
+/**
+ * lpt_init_rd - initialize the LPT for reading.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int lpt_init_rd(struct ubifs_info *c)
+{
+	int err, i;
+
+	c->ltab = vmalloc(array_size(sizeof(struct ubifs_lpt_lprops),
+				     c->lpt_lebs));
+	if (!c->ltab)
+		return -ENOMEM;
+
+	i = max_t(int, c->nnode_sz, c->pnode_sz);
+	c->lpt_nod_buf = kmalloc(i, GFP_KERNEL);
+	if (!c->lpt_nod_buf)
+		return -ENOMEM;
+
+	for (i = 0; i < LPROPS_HEAP_CNT; i++) {
+		c->lpt_heap[i].arr = kmalloc_array(LPT_HEAP_SZ,
+						   sizeof(void *),
+						   GFP_KERNEL);
+		if (!c->lpt_heap[i].arr)
+			return -ENOMEM;
+		c->lpt_heap[i].cnt = 0;
+		c->lpt_heap[i].max_cnt = LPT_HEAP_SZ;
+	}
+
+	c->dirty_idx.arr = kmalloc_array(LPT_HEAP_SZ, sizeof(void *),
+					 GFP_KERNEL);
+	if (!c->dirty_idx.arr)
+		return -ENOMEM;
+	c->dirty_idx.cnt = 0;
+	c->dirty_idx.max_cnt = LPT_HEAP_SZ;
+
+	err = read_ltab(c);
+	if (err)
+		return err;
+
+	err = lpt_check_hash(c);
+	if (err)
+		return err;
+
+	dbg_lp("space_bits %d", c->space_bits);
+	dbg_lp("lpt_lnum_bits %d", c->lpt_lnum_bits);
+	dbg_lp("lpt_offs_bits %d", c->lpt_offs_bits);
+	dbg_lp("lpt_spc_bits %d", c->lpt_spc_bits);
+	dbg_lp("pcnt_bits %d", c->pcnt_bits);
+	dbg_lp("lnum_bits %d", c->lnum_bits);
+	dbg_lp("pnode_sz %d", c->pnode_sz);
+	dbg_lp("nnode_sz %d", c->nnode_sz);
+	dbg_lp("ltab_sz %d", c->ltab_sz);
+	dbg_lp("lsave_sz %d", c->lsave_sz);
+	dbg_lp("lsave_cnt %d", c->lsave_cnt);
+	dbg_lp("lpt_hght %d", c->lpt_hght);
+	dbg_lp("big_lpt %u", c->big_lpt);
+	dbg_lp("LPT root is at %d:%d", c->lpt_lnum, c->lpt_offs);
+	dbg_lp("LPT head is at %d:%d", c->nhead_lnum, c->nhead_offs);
+	dbg_lp("LPT ltab is at %d:%d", c->ltab_lnum, c->ltab_offs);
+	if (c->big_lpt)
+		dbg_lp("LPT lsave is at %d:%d", c->lsave_lnum, c->lsave_offs);
+
+	return 0;
+}
+
+/**
+ * lpt_init_wr - initialize the LPT for writing.
+ * @c: UBIFS file-system description object
+ *
+ * 'lpt_init_rd()' must have been called already.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int lpt_init_wr(struct ubifs_info *c)
+{
+	int err, i;
+
+	c->ltab_cmt = vmalloc(array_size(sizeof(struct ubifs_lpt_lprops),
+					 c->lpt_lebs));
+	if (!c->ltab_cmt)
+		return -ENOMEM;
+
+	c->lpt_buf = vmalloc(c->leb_size);
+	if (!c->lpt_buf)
+		return -ENOMEM;
+
+	if (c->big_lpt) {
+		c->lsave = kmalloc_array(c->lsave_cnt, sizeof(int), GFP_NOFS);
+		if (!c->lsave)
+			return -ENOMEM;
+		err = read_lsave(c);
+		if (err)
+			return err;
+	}
+
+	for (i = 0; i < c->lpt_lebs; i++)
+		if (c->ltab[i].free == c->leb_size) {
+			err = ubifs_leb_unmap(c, i + c->lpt_first);
+			if (err)
+				return err;
+		}
+
+	return 0;
+}
+
+/**
+ * ubifs_lpt_init - initialize the LPT.
+ * @c: UBIFS file-system description object
+ * @rd: whether to initialize lpt for reading
+ * @wr: whether to initialize lpt for writing
+ *
+ * For mounting 'rw', @rd and @wr are both true. For mounting 'ro', @rd is true
+ * and @wr is false. For mounting from 'ro' to 'rw', @rd is false and @wr is
+ * true.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_lpt_init(struct ubifs_info *c, int rd, int wr)
+{
+	int err;
+
+	if (rd) {
+		err = lpt_init_rd(c);
+		if (err)
+			goto out_err;
+	}
+
+	if (wr) {
+		err = lpt_init_wr(c);
+		if (err)
+			goto out_err;
+	}
+
+	return 0;
+
+out_err:
+	if (wr)
+		ubifs_lpt_free(c, 1);
+	if (rd)
+		ubifs_lpt_free(c, 0);
+	return err;
+}
+
+/**
+ * struct lpt_scan_node - somewhere to put nodes while we scan LPT.
+ * @nnode: where to keep a nnode
+ * @pnode: where to keep a pnode
+ * @cnode: where to keep a cnode
+ * @in_tree: is the node in the tree in memory
+ * @ptr.nnode: pointer to the nnode (if it is an nnode) which may be here or in
+ * the tree
+ * @ptr.pnode: ditto for pnode
+ * @ptr.cnode: ditto for cnode
+ */
+struct lpt_scan_node {
+	union {
+		struct ubifs_nnode nnode;
+		struct ubifs_pnode pnode;
+		struct ubifs_cnode cnode;
+	};
+	int in_tree;
+	union {
+		struct ubifs_nnode *nnode;
+		struct ubifs_pnode *pnode;
+		struct ubifs_cnode *cnode;
+	} ptr;
+};
+
+/**
+ * scan_get_nnode - for the scan, get a nnode from either the tree or flash.
+ * @c: the UBIFS file-system description object
+ * @path: where to put the nnode
+ * @parent: parent of the nnode
+ * @iip: index in parent of the nnode
+ *
+ * This function returns a pointer to the nnode on success or a negative error
+ * code on failure.
+ */
+static struct ubifs_nnode *scan_get_nnode(struct ubifs_info *c,
+					  struct lpt_scan_node *path,
+					  struct ubifs_nnode *parent, int iip)
+{
+	struct ubifs_nbranch *branch;
+	struct ubifs_nnode *nnode;
+	void *buf = c->lpt_nod_buf;
+	int err;
+
+	branch = &parent->nbranch[iip];
+	nnode = branch->nnode;
+	if (nnode) {
+		path->in_tree = 1;
+		path->ptr.nnode = nnode;
+		return nnode;
+	}
+	nnode = &path->nnode;
+	path->in_tree = 0;
+	path->ptr.nnode = nnode;
+	memset(nnode, 0, sizeof(struct ubifs_nnode));
+	if (branch->lnum == 0) {
+		/*
+		 * This nnode was not written which just means that the LEB
+		 * properties in the subtree below it describe empty LEBs. We
+		 * make the nnode as though we had read it, which in fact means
+		 * doing almost nothing.
+		 */
+		if (c->big_lpt)
+			nnode->num = calc_nnode_num_from_parent(c, parent, iip);
+	} else {
+		err = ubifs_leb_read(c, branch->lnum, buf, branch->offs,
+				     c->nnode_sz, 1);
+		if (err)
+			return ERR_PTR(err);
+		err = ubifs_unpack_nnode(c, buf, nnode);
+		if (err)
+			return ERR_PTR(err);
+	}
+	err = validate_nnode(c, nnode, parent, iip);
+	if (err)
+		return ERR_PTR(err);
+	if (!c->big_lpt)
+		nnode->num = calc_nnode_num_from_parent(c, parent, iip);
+	nnode->level = parent->level - 1;
+	nnode->parent = parent;
+	nnode->iip = iip;
+	return nnode;
+}
+
+/**
+ * scan_get_pnode - for the scan, get a pnode from either the tree or flash.
+ * @c: the UBIFS file-system description object
+ * @path: where to put the pnode
+ * @parent: parent of the pnode
+ * @iip: index in parent of the pnode
+ *
+ * This function returns a pointer to the pnode on success or a negative error
+ * code on failure.
+ */
+static struct ubifs_pnode *scan_get_pnode(struct ubifs_info *c,
+					  struct lpt_scan_node *path,
+					  struct ubifs_nnode *parent, int iip)
+{
+	struct ubifs_nbranch *branch;
+	struct ubifs_pnode *pnode;
+	void *buf = c->lpt_nod_buf;
+	int err;
+
+	branch = &parent->nbranch[iip];
+	pnode = branch->pnode;
+	if (pnode) {
+		path->in_tree = 1;
+		path->ptr.pnode = pnode;
+		return pnode;
+	}
+	pnode = &path->pnode;
+	path->in_tree = 0;
+	path->ptr.pnode = pnode;
+	memset(pnode, 0, sizeof(struct ubifs_pnode));
+	if (branch->lnum == 0) {
+		/*
+		 * This pnode was not written which just means that the LEB
+		 * properties in it describe empty LEBs. We make the pnode as
+		 * though we had read it.
+		 */
+		int i;
+
+		if (c->big_lpt)
+			pnode->num = calc_pnode_num_from_parent(c, parent, iip);
+		for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+			struct ubifs_lprops * const lprops = &pnode->lprops[i];
+
+			lprops->free = c->leb_size;
+			lprops->flags = ubifs_categorize_lprops(c, lprops);
+		}
+	} else {
+		ubifs_assert(c, branch->lnum >= c->lpt_first &&
+			     branch->lnum <= c->lpt_last);
+		ubifs_assert(c, branch->offs >= 0 && branch->offs < c->leb_size);
+		err = ubifs_leb_read(c, branch->lnum, buf, branch->offs,
+				     c->pnode_sz, 1);
+		if (err)
+			return ERR_PTR(err);
+		err = unpack_pnode(c, buf, pnode);
+		if (err)
+			return ERR_PTR(err);
+	}
+	err = validate_pnode(c, pnode, parent, iip);
+	if (err)
+		return ERR_PTR(err);
+	if (!c->big_lpt)
+		pnode->num = calc_pnode_num_from_parent(c, parent, iip);
+	pnode->parent = parent;
+	pnode->iip = iip;
+	set_pnode_lnum(c, pnode);
+	return pnode;
+}
+
+/**
+ * ubifs_lpt_scan_nolock - scan the LPT.
+ * @c: the UBIFS file-system description object
+ * @start_lnum: LEB number from which to start scanning
+ * @end_lnum: LEB number at which to stop scanning
+ * @scan_cb: callback function called for each lprops
+ * @data: data to be passed to the callback function
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_lpt_scan_nolock(struct ubifs_info *c, int start_lnum, int end_lnum,
+			  ubifs_lpt_scan_callback scan_cb, void *data)
+{
+	int err = 0, i, h, iip, shft;
+	struct ubifs_nnode *nnode;
+	struct ubifs_pnode *pnode;
+	struct lpt_scan_node *path;
+
+	if (start_lnum == -1) {
+		start_lnum = end_lnum + 1;
+		if (start_lnum >= c->leb_cnt)
+			start_lnum = c->main_first;
+	}
+
+	ubifs_assert(c, start_lnum >= c->main_first && start_lnum < c->leb_cnt);
+	ubifs_assert(c, end_lnum >= c->main_first && end_lnum < c->leb_cnt);
+
+	if (!c->nroot) {
+		err = ubifs_read_nnode(c, NULL, 0);
+		if (err)
+			return err;
+	}
+
+	path = kmalloc_array(c->lpt_hght + 1, sizeof(struct lpt_scan_node),
+			     GFP_NOFS);
+	if (!path)
+		return -ENOMEM;
+
+	path[0].ptr.nnode = c->nroot;
+	path[0].in_tree = 1;
+again:
+	/* Descend to the pnode containing start_lnum */
+	nnode = c->nroot;
+	i = start_lnum - c->main_first;
+	shft = c->lpt_hght * UBIFS_LPT_FANOUT_SHIFT;
+	for (h = 1; h < c->lpt_hght; h++) {
+		iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
+		shft -= UBIFS_LPT_FANOUT_SHIFT;
+		nnode = scan_get_nnode(c, path + h, nnode, iip);
+		if (IS_ERR(nnode)) {
+			err = PTR_ERR(nnode);
+			goto out;
+		}
+	}
+	iip = ((i >> shft) & (UBIFS_LPT_FANOUT - 1));
+	pnode = scan_get_pnode(c, path + h, nnode, iip);
+	if (IS_ERR(pnode)) {
+		err = PTR_ERR(pnode);
+		goto out;
+	}
+	iip = (i & (UBIFS_LPT_FANOUT - 1));
+
+	/* Loop for each lprops */
+	while (1) {
+		struct ubifs_lprops *lprops = &pnode->lprops[iip];
+		int ret, lnum = lprops->lnum;
+
+		ret = scan_cb(c, lprops, path[h].in_tree, data);
+		if (ret < 0) {
+			err = ret;
+			goto out;
+		}
+		if (ret & LPT_SCAN_ADD) {
+			/* Add all the nodes in path to the tree in memory */
+			for (h = 1; h < c->lpt_hght; h++) {
+				const size_t sz = sizeof(struct ubifs_nnode);
+				struct ubifs_nnode *parent;
+
+				if (path[h].in_tree)
+					continue;
+				nnode = kmemdup(&path[h].nnode, sz, GFP_NOFS);
+				if (!nnode) {
+					err = -ENOMEM;
+					goto out;
+				}
+				parent = nnode->parent;
+				parent->nbranch[nnode->iip].nnode = nnode;
+				path[h].ptr.nnode = nnode;
+				path[h].in_tree = 1;
+				path[h + 1].cnode.parent = nnode;
+			}
+			if (path[h].in_tree)
+				ubifs_ensure_cat(c, lprops);
+			else {
+				const size_t sz = sizeof(struct ubifs_pnode);
+				struct ubifs_nnode *parent;
+
+				pnode = kmemdup(&path[h].pnode, sz, GFP_NOFS);
+				if (!pnode) {
+					err = -ENOMEM;
+					goto out;
+				}
+				parent = pnode->parent;
+				parent->nbranch[pnode->iip].pnode = pnode;
+				path[h].ptr.pnode = pnode;
+				path[h].in_tree = 1;
+				update_cats(c, pnode);
+				c->pnodes_have += 1;
+			}
+			err = dbg_check_lpt_nodes(c, (struct ubifs_cnode *)
+						  c->nroot, 0, 0);
+			if (err)
+				goto out;
+			err = dbg_check_cats(c);
+			if (err)
+				goto out;
+		}
+		if (ret & LPT_SCAN_STOP) {
+			err = 0;
+			break;
+		}
+		/* Get the next lprops */
+		if (lnum == end_lnum) {
+			/*
+			 * We got to the end without finding what we were
+			 * looking for
+			 */
+			err = -ENOSPC;
+			goto out;
+		}
+		if (lnum + 1 >= c->leb_cnt) {
+			/* Wrap-around to the beginning */
+			start_lnum = c->main_first;
+			goto again;
+		}
+		if (iip + 1 < UBIFS_LPT_FANOUT) {
+			/* Next lprops is in the same pnode */
+			iip += 1;
+			continue;
+		}
+		/* We need to get the next pnode. Go up until we can go right */
+		iip = pnode->iip;
+		while (1) {
+			h -= 1;
+			ubifs_assert(c, h >= 0);
+			nnode = path[h].ptr.nnode;
+			if (iip + 1 < UBIFS_LPT_FANOUT)
+				break;
+			iip = nnode->iip;
+		}
+		/* Go right */
+		iip += 1;
+		/* Descend to the pnode */
+		h += 1;
+		for (; h < c->lpt_hght; h++) {
+			nnode = scan_get_nnode(c, path + h, nnode, iip);
+			if (IS_ERR(nnode)) {
+				err = PTR_ERR(nnode);
+				goto out;
+			}
+			iip = 0;
+		}
+		pnode = scan_get_pnode(c, path + h, nnode, iip);
+		if (IS_ERR(pnode)) {
+			err = PTR_ERR(pnode);
+			goto out;
+		}
+		iip = 0;
+	}
+out:
+	kfree(path);
+	return err;
+}
+
+/**
+ * dbg_chk_pnode - check a pnode.
+ * @c: the UBIFS file-system description object
+ * @pnode: pnode to check
+ * @col: pnode column
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int dbg_chk_pnode(struct ubifs_info *c, struct ubifs_pnode *pnode,
+			 int col)
+{
+	int i;
+
+	if (pnode->num != col) {
+		ubifs_err(c, "pnode num %d expected %d parent num %d iip %d",
+			  pnode->num, col, pnode->parent->num, pnode->iip);
+		return -EINVAL;
+	}
+	for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+		struct ubifs_lprops *lp, *lprops = &pnode->lprops[i];
+		int lnum = (pnode->num << UBIFS_LPT_FANOUT_SHIFT) + i +
+			   c->main_first;
+		int found, cat = lprops->flags & LPROPS_CAT_MASK;
+		struct ubifs_lpt_heap *heap;
+		struct list_head *list = NULL;
+
+		if (lnum >= c->leb_cnt)
+			continue;
+		if (lprops->lnum != lnum) {
+			ubifs_err(c, "bad LEB number %d expected %d",
+				  lprops->lnum, lnum);
+			return -EINVAL;
+		}
+		if (lprops->flags & LPROPS_TAKEN) {
+			if (cat != LPROPS_UNCAT) {
+				ubifs_err(c, "LEB %d taken but not uncat %d",
+					  lprops->lnum, cat);
+				return -EINVAL;
+			}
+			continue;
+		}
+		if (lprops->flags & LPROPS_INDEX) {
+			switch (cat) {
+			case LPROPS_UNCAT:
+			case LPROPS_DIRTY_IDX:
+			case LPROPS_FRDI_IDX:
+				break;
+			default:
+				ubifs_err(c, "LEB %d index but cat %d",
+					  lprops->lnum, cat);
+				return -EINVAL;
+			}
+		} else {
+			switch (cat) {
+			case LPROPS_UNCAT:
+			case LPROPS_DIRTY:
+			case LPROPS_FREE:
+			case LPROPS_EMPTY:
+			case LPROPS_FREEABLE:
+				break;
+			default:
+				ubifs_err(c, "LEB %d not index but cat %d",
+					  lprops->lnum, cat);
+				return -EINVAL;
+			}
+		}
+		switch (cat) {
+		case LPROPS_UNCAT:
+			list = &c->uncat_list;
+			break;
+		case LPROPS_EMPTY:
+			list = &c->empty_list;
+			break;
+		case LPROPS_FREEABLE:
+			list = &c->freeable_list;
+			break;
+		case LPROPS_FRDI_IDX:
+			list = &c->frdi_idx_list;
+			break;
+		}
+		found = 0;
+		switch (cat) {
+		case LPROPS_DIRTY:
+		case LPROPS_DIRTY_IDX:
+		case LPROPS_FREE:
+			heap = &c->lpt_heap[cat - 1];
+			if (lprops->hpos < heap->cnt &&
+			    heap->arr[lprops->hpos] == lprops)
+				found = 1;
+			break;
+		case LPROPS_UNCAT:
+		case LPROPS_EMPTY:
+		case LPROPS_FREEABLE:
+		case LPROPS_FRDI_IDX:
+			list_for_each_entry(lp, list, list)
+				if (lprops == lp) {
+					found = 1;
+					break;
+				}
+			break;
+		}
+		if (!found) {
+			ubifs_err(c, "LEB %d cat %d not found in cat heap/list",
+				  lprops->lnum, cat);
+			return -EINVAL;
+		}
+		switch (cat) {
+		case LPROPS_EMPTY:
+			if (lprops->free != c->leb_size) {
+				ubifs_err(c, "LEB %d cat %d free %d dirty %d",
+					  lprops->lnum, cat, lprops->free,
+					  lprops->dirty);
+				return -EINVAL;
+			}
+			break;
+		case LPROPS_FREEABLE:
+		case LPROPS_FRDI_IDX:
+			if (lprops->free + lprops->dirty != c->leb_size) {
+				ubifs_err(c, "LEB %d cat %d free %d dirty %d",
+					  lprops->lnum, cat, lprops->free,
+					  lprops->dirty);
+				return -EINVAL;
+			}
+			break;
+		}
+	}
+	return 0;
+}
+
+/**
+ * dbg_check_lpt_nodes - check nnodes and pnodes.
+ * @c: the UBIFS file-system description object
+ * @cnode: next cnode (nnode or pnode) to check
+ * @row: row of cnode (root is zero)
+ * @col: column of cnode (leftmost is zero)
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int dbg_check_lpt_nodes(struct ubifs_info *c, struct ubifs_cnode *cnode,
+			int row, int col)
+{
+	struct ubifs_nnode *nnode, *nn;
+	struct ubifs_cnode *cn;
+	int num, iip = 0, err;
+
+	if (!dbg_is_chk_lprops(c))
+		return 0;
+
+	while (cnode) {
+		ubifs_assert(c, row >= 0);
+		nnode = cnode->parent;
+		if (cnode->level) {
+			/* cnode is a nnode */
+			num = calc_nnode_num(row, col);
+			if (cnode->num != num) {
+				ubifs_err(c, "nnode num %d expected %d parent num %d iip %d",
+					  cnode->num, num,
+					  (nnode ? nnode->num : 0), cnode->iip);
+				return -EINVAL;
+			}
+			nn = (struct ubifs_nnode *)cnode;
+			while (iip < UBIFS_LPT_FANOUT) {
+				cn = nn->nbranch[iip].cnode;
+				if (cn) {
+					/* Go down */
+					row += 1;
+					col <<= UBIFS_LPT_FANOUT_SHIFT;
+					col += iip;
+					iip = 0;
+					cnode = cn;
+					break;
+				}
+				/* Go right */
+				iip += 1;
+			}
+			if (iip < UBIFS_LPT_FANOUT)
+				continue;
+		} else {
+			struct ubifs_pnode *pnode;
+
+			/* cnode is a pnode */
+			pnode = (struct ubifs_pnode *)cnode;
+			err = dbg_chk_pnode(c, pnode, col);
+			if (err)
+				return err;
+		}
+		/* Go up and to the right */
+		row -= 1;
+		col >>= UBIFS_LPT_FANOUT_SHIFT;
+		iip = cnode->iip + 1;
+		cnode = (struct ubifs_cnode *)nnode;
+	}
+	return 0;
+}
diff --git a/ubifs-utils/libubifs/lpt_commit.c b/ubifs-utils/libubifs/lpt_commit.c
new file mode 100644
index 00000000..c4d07932
--- /dev/null
+++ b/ubifs-utils/libubifs/lpt_commit.c
@@ -0,0 +1,1997 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file implements commit-related functionality of the LEB properties
+ * subsystem.
+ */
+
+#include <linux/crc16.h>
+#include <linux/slab.h>
+#include <linux/random.h>
+#include "ubifs.h"
+
+static int dbg_populate_lsave(struct ubifs_info *c);
+
+/**
+ * first_dirty_cnode - find first dirty cnode.
+ * @c: UBIFS file-system description object
+ * @nnode: nnode at which to start
+ *
+ * This function returns the first dirty cnode or %NULL if there is not one.
+ */
+static struct ubifs_cnode *first_dirty_cnode(const struct ubifs_info *c, struct ubifs_nnode *nnode)
+{
+	ubifs_assert(c, nnode);
+	while (1) {
+		int i, cont = 0;
+
+		for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+			struct ubifs_cnode *cnode;
+
+			cnode = nnode->nbranch[i].cnode;
+			if (cnode &&
+			    test_bit(DIRTY_CNODE, &cnode->flags)) {
+				if (cnode->level == 0)
+					return cnode;
+				nnode = (struct ubifs_nnode *)cnode;
+				cont = 1;
+				break;
+			}
+		}
+		if (!cont)
+			return (struct ubifs_cnode *)nnode;
+	}
+}
+
+/**
+ * next_dirty_cnode - find next dirty cnode.
+ * @c: UBIFS file-system description object
+ * @cnode: cnode from which to begin searching
+ *
+ * This function returns the next dirty cnode or %NULL if there is not one.
+ */
+static struct ubifs_cnode *next_dirty_cnode(const struct ubifs_info *c, struct ubifs_cnode *cnode)
+{
+	struct ubifs_nnode *nnode;
+	int i;
+
+	ubifs_assert(c, cnode);
+	nnode = cnode->parent;
+	if (!nnode)
+		return NULL;
+	for (i = cnode->iip + 1; i < UBIFS_LPT_FANOUT; i++) {
+		cnode = nnode->nbranch[i].cnode;
+		if (cnode && test_bit(DIRTY_CNODE, &cnode->flags)) {
+			if (cnode->level == 0)
+				return cnode; /* cnode is a pnode */
+			/* cnode is a nnode */
+			return first_dirty_cnode(c, (struct ubifs_nnode *)cnode);
+		}
+	}
+	return (struct ubifs_cnode *)nnode;
+}
+
+/**
+ * get_cnodes_to_commit - create list of dirty cnodes to commit.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns the number of cnodes to commit.
+ */
+static int get_cnodes_to_commit(struct ubifs_info *c)
+{
+	struct ubifs_cnode *cnode, *cnext;
+	int cnt = 0;
+
+	if (!c->nroot)
+		return 0;
+
+	if (!test_bit(DIRTY_CNODE, &c->nroot->flags))
+		return 0;
+
+	c->lpt_cnext = first_dirty_cnode(c, c->nroot);
+	cnode = c->lpt_cnext;
+	if (!cnode)
+		return 0;
+	cnt += 1;
+	while (1) {
+		ubifs_assert(c, !test_bit(COW_CNODE, &cnode->flags));
+		__set_bit(COW_CNODE, &cnode->flags);
+		cnext = next_dirty_cnode(c, cnode);
+		if (!cnext) {
+			cnode->cnext = c->lpt_cnext;
+			break;
+		}
+		cnode->cnext = cnext;
+		cnode = cnext;
+		cnt += 1;
+	}
+	dbg_cmt("committing %d cnodes", cnt);
+	dbg_lp("committing %d cnodes", cnt);
+	ubifs_assert(c, cnt == c->dirty_nn_cnt + c->dirty_pn_cnt);
+	return cnt;
+}
+
+/**
+ * upd_ltab - update LPT LEB properties.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number
+ * @free: amount of free space
+ * @dirty: amount of dirty space to add
+ */
+static void upd_ltab(struct ubifs_info *c, int lnum, int free, int dirty)
+{
+	dbg_lp("LEB %d free %d dirty %d to %d +%d",
+	       lnum, c->ltab[lnum - c->lpt_first].free,
+	       c->ltab[lnum - c->lpt_first].dirty, free, dirty);
+	ubifs_assert(c, lnum >= c->lpt_first && lnum <= c->lpt_last);
+	c->ltab[lnum - c->lpt_first].free = free;
+	c->ltab[lnum - c->lpt_first].dirty += dirty;
+}
+
+/**
+ * alloc_lpt_leb - allocate an LPT LEB that is empty.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number is passed and returned here
+ *
+ * This function finds the next empty LEB in the ltab starting from @lnum. If a
+ * an empty LEB is found it is returned in @lnum and the function returns %0.
+ * Otherwise the function returns -ENOSPC.  Note however, that LPT is designed
+ * never to run out of space.
+ */
+static int alloc_lpt_leb(struct ubifs_info *c, int *lnum)
+{
+	int i, n;
+
+	n = *lnum - c->lpt_first + 1;
+	for (i = n; i < c->lpt_lebs; i++) {
+		if (c->ltab[i].tgc || c->ltab[i].cmt)
+			continue;
+		if (c->ltab[i].free == c->leb_size) {
+			c->ltab[i].cmt = 1;
+			*lnum = i + c->lpt_first;
+			return 0;
+		}
+	}
+
+	for (i = 0; i < n; i++) {
+		if (c->ltab[i].tgc || c->ltab[i].cmt)
+			continue;
+		if (c->ltab[i].free == c->leb_size) {
+			c->ltab[i].cmt = 1;
+			*lnum = i + c->lpt_first;
+			return 0;
+		}
+	}
+	return -ENOSPC;
+}
+
+/**
+ * layout_cnodes - layout cnodes for commit.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int layout_cnodes(struct ubifs_info *c)
+{
+	int lnum, offs, len, alen, done_lsave, done_ltab, err;
+	struct ubifs_cnode *cnode;
+
+	err = dbg_chk_lpt_sz(c, 0, 0);
+	if (err)
+		return err;
+	cnode = c->lpt_cnext;
+	if (!cnode)
+		return 0;
+	lnum = c->nhead_lnum;
+	offs = c->nhead_offs;
+	/* Try to place lsave and ltab nicely */
+	done_lsave = !c->big_lpt;
+	done_ltab = 0;
+	if (!done_lsave && offs + c->lsave_sz <= c->leb_size) {
+		done_lsave = 1;
+		c->lsave_lnum = lnum;
+		c->lsave_offs = offs;
+		offs += c->lsave_sz;
+		dbg_chk_lpt_sz(c, 1, c->lsave_sz);
+	}
+
+	if (offs + c->ltab_sz <= c->leb_size) {
+		done_ltab = 1;
+		c->ltab_lnum = lnum;
+		c->ltab_offs = offs;
+		offs += c->ltab_sz;
+		dbg_chk_lpt_sz(c, 1, c->ltab_sz);
+	}
+
+	do {
+		if (cnode->level) {
+			len = c->nnode_sz;
+			c->dirty_nn_cnt -= 1;
+		} else {
+			len = c->pnode_sz;
+			c->dirty_pn_cnt -= 1;
+		}
+		while (offs + len > c->leb_size) {
+			alen = ALIGN(offs, c->min_io_size);
+			upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
+			err = alloc_lpt_leb(c, &lnum);
+			if (err)
+				goto no_space;
+			offs = 0;
+			ubifs_assert(c, lnum >= c->lpt_first &&
+				     lnum <= c->lpt_last);
+			/* Try to place lsave and ltab nicely */
+			if (!done_lsave) {
+				done_lsave = 1;
+				c->lsave_lnum = lnum;
+				c->lsave_offs = offs;
+				offs += c->lsave_sz;
+				dbg_chk_lpt_sz(c, 1, c->lsave_sz);
+				continue;
+			}
+			if (!done_ltab) {
+				done_ltab = 1;
+				c->ltab_lnum = lnum;
+				c->ltab_offs = offs;
+				offs += c->ltab_sz;
+				dbg_chk_lpt_sz(c, 1, c->ltab_sz);
+				continue;
+			}
+			break;
+		}
+		if (cnode->parent) {
+			cnode->parent->nbranch[cnode->iip].lnum = lnum;
+			cnode->parent->nbranch[cnode->iip].offs = offs;
+		} else {
+			c->lpt_lnum = lnum;
+			c->lpt_offs = offs;
+		}
+		offs += len;
+		dbg_chk_lpt_sz(c, 1, len);
+		cnode = cnode->cnext;
+	} while (cnode && cnode != c->lpt_cnext);
+
+	/* Make sure to place LPT's save table */
+	if (!done_lsave) {
+		if (offs + c->lsave_sz > c->leb_size) {
+			alen = ALIGN(offs, c->min_io_size);
+			upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
+			err = alloc_lpt_leb(c, &lnum);
+			if (err)
+				goto no_space;
+			offs = 0;
+			ubifs_assert(c, lnum >= c->lpt_first &&
+				     lnum <= c->lpt_last);
+		}
+		done_lsave = 1;
+		c->lsave_lnum = lnum;
+		c->lsave_offs = offs;
+		offs += c->lsave_sz;
+		dbg_chk_lpt_sz(c, 1, c->lsave_sz);
+	}
+
+	/* Make sure to place LPT's own lprops table */
+	if (!done_ltab) {
+		if (offs + c->ltab_sz > c->leb_size) {
+			alen = ALIGN(offs, c->min_io_size);
+			upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
+			err = alloc_lpt_leb(c, &lnum);
+			if (err)
+				goto no_space;
+			offs = 0;
+			ubifs_assert(c, lnum >= c->lpt_first &&
+				     lnum <= c->lpt_last);
+		}
+		c->ltab_lnum = lnum;
+		c->ltab_offs = offs;
+		offs += c->ltab_sz;
+		dbg_chk_lpt_sz(c, 1, c->ltab_sz);
+	}
+
+	alen = ALIGN(offs, c->min_io_size);
+	upd_ltab(c, lnum, c->leb_size - alen, alen - offs);
+	dbg_chk_lpt_sz(c, 4, alen - offs);
+	err = dbg_chk_lpt_sz(c, 3, alen);
+	if (err)
+		return err;
+	return 0;
+
+no_space:
+	ubifs_err(c, "LPT out of space at LEB %d:%d needing %d, done_ltab %d, done_lsave %d",
+		  lnum, offs, len, done_ltab, done_lsave);
+	ubifs_dump_lpt_info(c);
+	ubifs_dump_lpt_lebs(c);
+	dump_stack();
+	return err;
+}
+
+/**
+ * realloc_lpt_leb - allocate an LPT LEB that is empty.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number is passed and returned here
+ *
+ * This function duplicates exactly the results of the function alloc_lpt_leb.
+ * It is used during end commit to reallocate the same LEB numbers that were
+ * allocated by alloc_lpt_leb during start commit.
+ *
+ * This function finds the next LEB that was allocated by the alloc_lpt_leb
+ * function starting from @lnum. If a LEB is found it is returned in @lnum and
+ * the function returns %0. Otherwise the function returns -ENOSPC.
+ * Note however, that LPT is designed never to run out of space.
+ */
+static int realloc_lpt_leb(struct ubifs_info *c, int *lnum)
+{
+	int i, n;
+
+	n = *lnum - c->lpt_first + 1;
+	for (i = n; i < c->lpt_lebs; i++)
+		if (c->ltab[i].cmt) {
+			c->ltab[i].cmt = 0;
+			*lnum = i + c->lpt_first;
+			return 0;
+		}
+
+	for (i = 0; i < n; i++)
+		if (c->ltab[i].cmt) {
+			c->ltab[i].cmt = 0;
+			*lnum = i + c->lpt_first;
+			return 0;
+		}
+	return -ENOSPC;
+}
+
+/**
+ * write_cnodes - write cnodes for commit.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int write_cnodes(struct ubifs_info *c)
+{
+	int lnum, offs, len, from, err, wlen, alen, done_ltab, done_lsave;
+	struct ubifs_cnode *cnode;
+	void *buf = c->lpt_buf;
+
+	cnode = c->lpt_cnext;
+	if (!cnode)
+		return 0;
+	lnum = c->nhead_lnum;
+	offs = c->nhead_offs;
+	from = offs;
+	/* Ensure empty LEB is unmapped */
+	if (offs == 0) {
+		err = ubifs_leb_unmap(c, lnum);
+		if (err)
+			return err;
+	}
+	/* Try to place lsave and ltab nicely */
+	done_lsave = !c->big_lpt;
+	done_ltab = 0;
+	if (!done_lsave && offs + c->lsave_sz <= c->leb_size) {
+		done_lsave = 1;
+		ubifs_pack_lsave(c, buf + offs, c->lsave);
+		offs += c->lsave_sz;
+		dbg_chk_lpt_sz(c, 1, c->lsave_sz);
+	}
+
+	if (offs + c->ltab_sz <= c->leb_size) {
+		done_ltab = 1;
+		ubifs_pack_ltab(c, buf + offs, c->ltab_cmt);
+		offs += c->ltab_sz;
+		dbg_chk_lpt_sz(c, 1, c->ltab_sz);
+	}
+
+	/* Loop for each cnode */
+	do {
+		if (cnode->level)
+			len = c->nnode_sz;
+		else
+			len = c->pnode_sz;
+		while (offs + len > c->leb_size) {
+			wlen = offs - from;
+			if (wlen) {
+				alen = ALIGN(wlen, c->min_io_size);
+				memset(buf + offs, 0xff, alen - wlen);
+				err = ubifs_leb_write(c, lnum, buf + from, from,
+						       alen);
+				if (err)
+					return err;
+			}
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
+			err = realloc_lpt_leb(c, &lnum);
+			if (err)
+				goto no_space;
+			offs = from = 0;
+			ubifs_assert(c, lnum >= c->lpt_first &&
+				     lnum <= c->lpt_last);
+			err = ubifs_leb_unmap(c, lnum);
+			if (err)
+				return err;
+			/* Try to place lsave and ltab nicely */
+			if (!done_lsave) {
+				done_lsave = 1;
+				ubifs_pack_lsave(c, buf + offs, c->lsave);
+				offs += c->lsave_sz;
+				dbg_chk_lpt_sz(c, 1, c->lsave_sz);
+				continue;
+			}
+			if (!done_ltab) {
+				done_ltab = 1;
+				ubifs_pack_ltab(c, buf + offs, c->ltab_cmt);
+				offs += c->ltab_sz;
+				dbg_chk_lpt_sz(c, 1, c->ltab_sz);
+				continue;
+			}
+			break;
+		}
+		if (cnode->level)
+			ubifs_pack_nnode(c, buf + offs,
+					 (struct ubifs_nnode *)cnode);
+		else
+			ubifs_pack_pnode(c, buf + offs,
+					 (struct ubifs_pnode *)cnode);
+		/*
+		 * The reason for the barriers is the same as in case of TNC.
+		 * See comment in 'write_index()'. 'dirty_cow_nnode()' and
+		 * 'dirty_cow_pnode()' are the functions for which this is
+		 * important.
+		 */
+		clear_bit(DIRTY_CNODE, &cnode->flags);
+		smp_mb__before_atomic();
+		clear_bit(COW_CNODE, &cnode->flags);
+		smp_mb__after_atomic();
+		offs += len;
+		dbg_chk_lpt_sz(c, 1, len);
+		cnode = cnode->cnext;
+	} while (cnode && cnode != c->lpt_cnext);
+
+	/* Make sure to place LPT's save table */
+	if (!done_lsave) {
+		if (offs + c->lsave_sz > c->leb_size) {
+			wlen = offs - from;
+			alen = ALIGN(wlen, c->min_io_size);
+			memset(buf + offs, 0xff, alen - wlen);
+			err = ubifs_leb_write(c, lnum, buf + from, from, alen);
+			if (err)
+				return err;
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
+			err = realloc_lpt_leb(c, &lnum);
+			if (err)
+				goto no_space;
+			offs = from = 0;
+			ubifs_assert(c, lnum >= c->lpt_first &&
+				     lnum <= c->lpt_last);
+			err = ubifs_leb_unmap(c, lnum);
+			if (err)
+				return err;
+		}
+		done_lsave = 1;
+		ubifs_pack_lsave(c, buf + offs, c->lsave);
+		offs += c->lsave_sz;
+		dbg_chk_lpt_sz(c, 1, c->lsave_sz);
+	}
+
+	/* Make sure to place LPT's own lprops table */
+	if (!done_ltab) {
+		if (offs + c->ltab_sz > c->leb_size) {
+			wlen = offs - from;
+			alen = ALIGN(wlen, c->min_io_size);
+			memset(buf + offs, 0xff, alen - wlen);
+			err = ubifs_leb_write(c, lnum, buf + from, from, alen);
+			if (err)
+				return err;
+			dbg_chk_lpt_sz(c, 2, c->leb_size - offs);
+			err = realloc_lpt_leb(c, &lnum);
+			if (err)
+				goto no_space;
+			offs = from = 0;
+			ubifs_assert(c, lnum >= c->lpt_first &&
+				     lnum <= c->lpt_last);
+			err = ubifs_leb_unmap(c, lnum);
+			if (err)
+				return err;
+		}
+		ubifs_pack_ltab(c, buf + offs, c->ltab_cmt);
+		offs += c->ltab_sz;
+		dbg_chk_lpt_sz(c, 1, c->ltab_sz);
+	}
+
+	/* Write remaining data in buffer */
+	wlen = offs - from;
+	alen = ALIGN(wlen, c->min_io_size);
+	memset(buf + offs, 0xff, alen - wlen);
+	err = ubifs_leb_write(c, lnum, buf + from, from, alen);
+	if (err)
+		return err;
+
+	dbg_chk_lpt_sz(c, 4, alen - wlen);
+	err = dbg_chk_lpt_sz(c, 3, ALIGN(offs, c->min_io_size));
+	if (err)
+		return err;
+
+	c->nhead_lnum = lnum;
+	c->nhead_offs = ALIGN(offs, c->min_io_size);
+
+	dbg_lp("LPT root is at %d:%d", c->lpt_lnum, c->lpt_offs);
+	dbg_lp("LPT head is at %d:%d", c->nhead_lnum, c->nhead_offs);
+	dbg_lp("LPT ltab is at %d:%d", c->ltab_lnum, c->ltab_offs);
+	if (c->big_lpt)
+		dbg_lp("LPT lsave is at %d:%d", c->lsave_lnum, c->lsave_offs);
+
+	return 0;
+
+no_space:
+	ubifs_err(c, "LPT out of space mismatch at LEB %d:%d needing %d, done_ltab %d, done_lsave %d",
+		  lnum, offs, len, done_ltab, done_lsave);
+	ubifs_dump_lpt_info(c);
+	ubifs_dump_lpt_lebs(c);
+	dump_stack();
+	return err;
+}
+
+/**
+ * next_pnode_to_dirty - find next pnode to dirty.
+ * @c: UBIFS file-system description object
+ * @pnode: pnode
+ *
+ * This function returns the next pnode to dirty or %NULL if there are no more
+ * pnodes.  Note that pnodes that have never been written (lnum == 0) are
+ * skipped.
+ */
+static struct ubifs_pnode *next_pnode_to_dirty(struct ubifs_info *c,
+					       struct ubifs_pnode *pnode)
+{
+	struct ubifs_nnode *nnode;
+	int iip;
+
+	/* Try to go right */
+	nnode = pnode->parent;
+	for (iip = pnode->iip + 1; iip < UBIFS_LPT_FANOUT; iip++) {
+		if (nnode->nbranch[iip].lnum)
+			return ubifs_get_pnode(c, nnode, iip);
+	}
+
+	/* Go up while can't go right */
+	do {
+		iip = nnode->iip + 1;
+		nnode = nnode->parent;
+		if (!nnode)
+			return NULL;
+		for (; iip < UBIFS_LPT_FANOUT; iip++) {
+			if (nnode->nbranch[iip].lnum)
+				break;
+		}
+	} while (iip >= UBIFS_LPT_FANOUT);
+
+	/* Go right */
+	nnode = ubifs_get_nnode(c, nnode, iip);
+	if (IS_ERR(nnode))
+		return (void *)nnode;
+
+	/* Go down to level 1 */
+	while (nnode->level > 1) {
+		for (iip = 0; iip < UBIFS_LPT_FANOUT; iip++) {
+			if (nnode->nbranch[iip].lnum)
+				break;
+		}
+		if (iip >= UBIFS_LPT_FANOUT) {
+			/*
+			 * Should not happen, but we need to keep going
+			 * if it does.
+			 */
+			iip = 0;
+		}
+		nnode = ubifs_get_nnode(c, nnode, iip);
+		if (IS_ERR(nnode))
+			return (void *)nnode;
+	}
+
+	for (iip = 0; iip < UBIFS_LPT_FANOUT; iip++)
+		if (nnode->nbranch[iip].lnum)
+			break;
+	if (iip >= UBIFS_LPT_FANOUT)
+		/* Should not happen, but we need to keep going if it does */
+		iip = 0;
+	return ubifs_get_pnode(c, nnode, iip);
+}
+
+/**
+ * add_pnode_dirt - add dirty space to LPT LEB properties.
+ * @c: UBIFS file-system description object
+ * @pnode: pnode for which to add dirt
+ */
+static void add_pnode_dirt(struct ubifs_info *c, struct ubifs_pnode *pnode)
+{
+	ubifs_add_lpt_dirt(c, pnode->parent->nbranch[pnode->iip].lnum,
+			   c->pnode_sz);
+}
+
+/**
+ * do_make_pnode_dirty - mark a pnode dirty.
+ * @c: UBIFS file-system description object
+ * @pnode: pnode to mark dirty
+ */
+static void do_make_pnode_dirty(struct ubifs_info *c, struct ubifs_pnode *pnode)
+{
+	/* Assumes cnext list is empty i.e. not called during commit */
+	if (!test_and_set_bit(DIRTY_CNODE, &pnode->flags)) {
+		struct ubifs_nnode *nnode;
+
+		c->dirty_pn_cnt += 1;
+		add_pnode_dirt(c, pnode);
+		/* Mark parent and ancestors dirty too */
+		nnode = pnode->parent;
+		while (nnode) {
+			if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
+				c->dirty_nn_cnt += 1;
+				ubifs_add_nnode_dirt(c, nnode);
+				nnode = nnode->parent;
+			} else
+				break;
+		}
+	}
+}
+
+/**
+ * make_tree_dirty - mark the entire LEB properties tree dirty.
+ * @c: UBIFS file-system description object
+ *
+ * This function is used by the "small" LPT model to cause the entire LEB
+ * properties tree to be written.  The "small" LPT model does not use LPT
+ * garbage collection because it is more efficient to write the entire tree
+ * (because it is small).
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int make_tree_dirty(struct ubifs_info *c)
+{
+	struct ubifs_pnode *pnode;
+
+	pnode = ubifs_pnode_lookup(c, 0);
+	if (IS_ERR(pnode))
+		return PTR_ERR(pnode);
+
+	while (pnode) {
+		do_make_pnode_dirty(c, pnode);
+		pnode = next_pnode_to_dirty(c, pnode);
+		if (IS_ERR(pnode))
+			return PTR_ERR(pnode);
+	}
+	return 0;
+}
+
+/**
+ * need_write_all - determine if the LPT area is running out of free space.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns %1 if the LPT area is running out of free space and %0
+ * if it is not.
+ */
+static int need_write_all(struct ubifs_info *c)
+{
+	long long free = 0;
+	int i;
+
+	for (i = 0; i < c->lpt_lebs; i++) {
+		if (i + c->lpt_first == c->nhead_lnum)
+			free += c->leb_size - c->nhead_offs;
+		else if (c->ltab[i].free == c->leb_size)
+			free += c->leb_size;
+		else if (c->ltab[i].free + c->ltab[i].dirty == c->leb_size)
+			free += c->leb_size;
+	}
+	/* Less than twice the size left */
+	if (free <= c->lpt_sz * 2)
+		return 1;
+	return 0;
+}
+
+/**
+ * lpt_tgc_start - start trivial garbage collection of LPT LEBs.
+ * @c: UBIFS file-system description object
+ *
+ * LPT trivial garbage collection is where a LPT LEB contains only dirty and
+ * free space and so may be reused as soon as the next commit is completed.
+ * This function is called during start commit to mark LPT LEBs for trivial GC.
+ */
+static void lpt_tgc_start(struct ubifs_info *c)
+{
+	int i;
+
+	for (i = 0; i < c->lpt_lebs; i++) {
+		if (i + c->lpt_first == c->nhead_lnum)
+			continue;
+		if (c->ltab[i].dirty > 0 &&
+		    c->ltab[i].free + c->ltab[i].dirty == c->leb_size) {
+			c->ltab[i].tgc = 1;
+			c->ltab[i].free = c->leb_size;
+			c->ltab[i].dirty = 0;
+			dbg_lp("LEB %d", i + c->lpt_first);
+		}
+	}
+}
+
+/**
+ * lpt_tgc_end - end trivial garbage collection of LPT LEBs.
+ * @c: UBIFS file-system description object
+ *
+ * LPT trivial garbage collection is where a LPT LEB contains only dirty and
+ * free space and so may be reused as soon as the next commit is completed.
+ * This function is called after the commit is completed (master node has been
+ * written) and un-maps LPT LEBs that were marked for trivial GC.
+ */
+static int lpt_tgc_end(struct ubifs_info *c)
+{
+	int i, err;
+
+	for (i = 0; i < c->lpt_lebs; i++)
+		if (c->ltab[i].tgc) {
+			err = ubifs_leb_unmap(c, i + c->lpt_first);
+			if (err)
+				return err;
+			c->ltab[i].tgc = 0;
+			dbg_lp("LEB %d", i + c->lpt_first);
+		}
+	return 0;
+}
+
+/**
+ * populate_lsave - fill the lsave array with important LEB numbers.
+ * @c: the UBIFS file-system description object
+ *
+ * This function is only called for the "big" model. It records a small number
+ * of LEB numbers of important LEBs.  Important LEBs are ones that are (from
+ * most important to least important): empty, freeable, freeable index, dirty
+ * index, dirty or free. Upon mount, we read this list of LEB numbers and bring
+ * their pnodes into memory.  That will stop us from having to scan the LPT
+ * straight away. For the "small" model we assume that scanning the LPT is no
+ * big deal.
+ */
+static void populate_lsave(struct ubifs_info *c)
+{
+	struct ubifs_lprops *lprops;
+	struct ubifs_lpt_heap *heap;
+	int i, cnt = 0;
+
+	ubifs_assert(c, c->big_lpt);
+	if (!(c->lpt_drty_flgs & LSAVE_DIRTY)) {
+		c->lpt_drty_flgs |= LSAVE_DIRTY;
+		ubifs_add_lpt_dirt(c, c->lsave_lnum, c->lsave_sz);
+	}
+
+	if (dbg_populate_lsave(c))
+		return;
+
+	list_for_each_entry(lprops, &c->empty_list, list) {
+		c->lsave[cnt++] = lprops->lnum;
+		if (cnt >= c->lsave_cnt)
+			return;
+	}
+	list_for_each_entry(lprops, &c->freeable_list, list) {
+		c->lsave[cnt++] = lprops->lnum;
+		if (cnt >= c->lsave_cnt)
+			return;
+	}
+	list_for_each_entry(lprops, &c->frdi_idx_list, list) {
+		c->lsave[cnt++] = lprops->lnum;
+		if (cnt >= c->lsave_cnt)
+			return;
+	}
+	heap = &c->lpt_heap[LPROPS_DIRTY_IDX - 1];
+	for (i = 0; i < heap->cnt; i++) {
+		c->lsave[cnt++] = heap->arr[i]->lnum;
+		if (cnt >= c->lsave_cnt)
+			return;
+	}
+	heap = &c->lpt_heap[LPROPS_DIRTY - 1];
+	for (i = 0; i < heap->cnt; i++) {
+		c->lsave[cnt++] = heap->arr[i]->lnum;
+		if (cnt >= c->lsave_cnt)
+			return;
+	}
+	heap = &c->lpt_heap[LPROPS_FREE - 1];
+	for (i = 0; i < heap->cnt; i++) {
+		c->lsave[cnt++] = heap->arr[i]->lnum;
+		if (cnt >= c->lsave_cnt)
+			return;
+	}
+	/* Fill it up completely */
+	while (cnt < c->lsave_cnt)
+		c->lsave[cnt++] = c->main_first;
+}
+
+/**
+ * nnode_lookup - lookup a nnode in the LPT.
+ * @c: UBIFS file-system description object
+ * @i: nnode number
+ *
+ * This function returns a pointer to the nnode on success or a negative
+ * error code on failure.
+ */
+static struct ubifs_nnode *nnode_lookup(struct ubifs_info *c, int i)
+{
+	int err, iip;
+	struct ubifs_nnode *nnode;
+
+	if (!c->nroot) {
+		err = ubifs_read_nnode(c, NULL, 0);
+		if (err)
+			return ERR_PTR(err);
+	}
+	nnode = c->nroot;
+	while (1) {
+		iip = i & (UBIFS_LPT_FANOUT - 1);
+		i >>= UBIFS_LPT_FANOUT_SHIFT;
+		if (!i)
+			break;
+		nnode = ubifs_get_nnode(c, nnode, iip);
+		if (IS_ERR(nnode))
+			return nnode;
+	}
+	return nnode;
+}
+
+/**
+ * make_nnode_dirty - find a nnode and, if found, make it dirty.
+ * @c: UBIFS file-system description object
+ * @node_num: nnode number of nnode to make dirty
+ * @lnum: LEB number where nnode was written
+ * @offs: offset where nnode was written
+ *
+ * This function is used by LPT garbage collection.  LPT garbage collection is
+ * used only for the "big" LPT model (c->big_lpt == 1).  Garbage collection
+ * simply involves marking all the nodes in the LEB being garbage-collected as
+ * dirty.  The dirty nodes are written next commit, after which the LEB is free
+ * to be reused.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int make_nnode_dirty(struct ubifs_info *c, int node_num, int lnum,
+			    int offs)
+{
+	struct ubifs_nnode *nnode;
+
+	nnode = nnode_lookup(c, node_num);
+	if (IS_ERR(nnode))
+		return PTR_ERR(nnode);
+	if (nnode->parent) {
+		struct ubifs_nbranch *branch;
+
+		branch = &nnode->parent->nbranch[nnode->iip];
+		if (branch->lnum != lnum || branch->offs != offs)
+			return 0; /* nnode is obsolete */
+	} else if (c->lpt_lnum != lnum || c->lpt_offs != offs)
+			return 0; /* nnode is obsolete */
+	/* Assumes cnext list is empty i.e. not called during commit */
+	if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
+		c->dirty_nn_cnt += 1;
+		ubifs_add_nnode_dirt(c, nnode);
+		/* Mark parent and ancestors dirty too */
+		nnode = nnode->parent;
+		while (nnode) {
+			if (!test_and_set_bit(DIRTY_CNODE, &nnode->flags)) {
+				c->dirty_nn_cnt += 1;
+				ubifs_add_nnode_dirt(c, nnode);
+				nnode = nnode->parent;
+			} else
+				break;
+		}
+	}
+	return 0;
+}
+
+/**
+ * make_pnode_dirty - find a pnode and, if found, make it dirty.
+ * @c: UBIFS file-system description object
+ * @node_num: pnode number of pnode to make dirty
+ * @lnum: LEB number where pnode was written
+ * @offs: offset where pnode was written
+ *
+ * This function is used by LPT garbage collection.  LPT garbage collection is
+ * used only for the "big" LPT model (c->big_lpt == 1).  Garbage collection
+ * simply involves marking all the nodes in the LEB being garbage-collected as
+ * dirty.  The dirty nodes are written next commit, after which the LEB is free
+ * to be reused.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int make_pnode_dirty(struct ubifs_info *c, int node_num, int lnum,
+			    int offs)
+{
+	struct ubifs_pnode *pnode;
+	struct ubifs_nbranch *branch;
+
+	pnode = ubifs_pnode_lookup(c, node_num);
+	if (IS_ERR(pnode))
+		return PTR_ERR(pnode);
+	branch = &pnode->parent->nbranch[pnode->iip];
+	if (branch->lnum != lnum || branch->offs != offs)
+		return 0;
+	do_make_pnode_dirty(c, pnode);
+	return 0;
+}
+
+/**
+ * make_ltab_dirty - make ltab node dirty.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number where ltab was written
+ * @offs: offset where ltab was written
+ *
+ * This function is used by LPT garbage collection.  LPT garbage collection is
+ * used only for the "big" LPT model (c->big_lpt == 1).  Garbage collection
+ * simply involves marking all the nodes in the LEB being garbage-collected as
+ * dirty.  The dirty nodes are written next commit, after which the LEB is free
+ * to be reused.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int make_ltab_dirty(struct ubifs_info *c, int lnum, int offs)
+{
+	if (lnum != c->ltab_lnum || offs != c->ltab_offs)
+		return 0; /* This ltab node is obsolete */
+	if (!(c->lpt_drty_flgs & LTAB_DIRTY)) {
+		c->lpt_drty_flgs |= LTAB_DIRTY;
+		ubifs_add_lpt_dirt(c, c->ltab_lnum, c->ltab_sz);
+	}
+	return 0;
+}
+
+/**
+ * make_lsave_dirty - make lsave node dirty.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number where lsave was written
+ * @offs: offset where lsave was written
+ *
+ * This function is used by LPT garbage collection.  LPT garbage collection is
+ * used only for the "big" LPT model (c->big_lpt == 1).  Garbage collection
+ * simply involves marking all the nodes in the LEB being garbage-collected as
+ * dirty.  The dirty nodes are written next commit, after which the LEB is free
+ * to be reused.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int make_lsave_dirty(struct ubifs_info *c, int lnum, int offs)
+{
+	if (lnum != c->lsave_lnum || offs != c->lsave_offs)
+		return 0; /* This lsave node is obsolete */
+	if (!(c->lpt_drty_flgs & LSAVE_DIRTY)) {
+		c->lpt_drty_flgs |= LSAVE_DIRTY;
+		ubifs_add_lpt_dirt(c, c->lsave_lnum, c->lsave_sz);
+	}
+	return 0;
+}
+
+/**
+ * make_node_dirty - make node dirty.
+ * @c: UBIFS file-system description object
+ * @node_type: LPT node type
+ * @node_num: node number
+ * @lnum: LEB number where node was written
+ * @offs: offset where node was written
+ *
+ * This function is used by LPT garbage collection.  LPT garbage collection is
+ * used only for the "big" LPT model (c->big_lpt == 1).  Garbage collection
+ * simply involves marking all the nodes in the LEB being garbage-collected as
+ * dirty.  The dirty nodes are written next commit, after which the LEB is free
+ * to be reused.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int make_node_dirty(struct ubifs_info *c, int node_type, int node_num,
+			   int lnum, int offs)
+{
+	switch (node_type) {
+	case UBIFS_LPT_NNODE:
+		return make_nnode_dirty(c, node_num, lnum, offs);
+	case UBIFS_LPT_PNODE:
+		return make_pnode_dirty(c, node_num, lnum, offs);
+	case UBIFS_LPT_LTAB:
+		return make_ltab_dirty(c, lnum, offs);
+	case UBIFS_LPT_LSAVE:
+		return make_lsave_dirty(c, lnum, offs);
+	}
+	return -EINVAL;
+}
+
+/**
+ * get_lpt_node_len - return the length of a node based on its type.
+ * @c: UBIFS file-system description object
+ * @node_type: LPT node type
+ */
+static int get_lpt_node_len(const struct ubifs_info *c, int node_type)
+{
+	switch (node_type) {
+	case UBIFS_LPT_NNODE:
+		return c->nnode_sz;
+	case UBIFS_LPT_PNODE:
+		return c->pnode_sz;
+	case UBIFS_LPT_LTAB:
+		return c->ltab_sz;
+	case UBIFS_LPT_LSAVE:
+		return c->lsave_sz;
+	}
+	return 0;
+}
+
+/**
+ * get_pad_len - return the length of padding in a buffer.
+ * @c: UBIFS file-system description object
+ * @buf: buffer
+ * @len: length of buffer
+ */
+static int get_pad_len(const struct ubifs_info *c, uint8_t *buf, int len)
+{
+	int offs, pad_len;
+
+	if (c->min_io_size == 1)
+		return 0;
+	offs = c->leb_size - len;
+	pad_len = ALIGN(offs, c->min_io_size) - offs;
+	return pad_len;
+}
+
+/**
+ * get_lpt_node_type - return type (and node number) of a node in a buffer.
+ * @c: UBIFS file-system description object
+ * @buf: buffer
+ * @node_num: node number is returned here
+ */
+static int get_lpt_node_type(const struct ubifs_info *c, uint8_t *buf,
+			     int *node_num)
+{
+	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
+	int pos = 0, node_type;
+
+	node_type = ubifs_unpack_bits(c, &addr, &pos, UBIFS_LPT_TYPE_BITS);
+	*node_num = ubifs_unpack_bits(c, &addr, &pos, c->pcnt_bits);
+	return node_type;
+}
+
+/**
+ * is_a_node - determine if a buffer contains a node.
+ * @c: UBIFS file-system description object
+ * @buf: buffer
+ * @len: length of buffer
+ *
+ * This function returns %1 if the buffer contains a node or %0 if it does not.
+ */
+static int is_a_node(const struct ubifs_info *c, uint8_t *buf, int len)
+{
+	uint8_t *addr = buf + UBIFS_LPT_CRC_BYTES;
+	int pos = 0, node_type, node_len;
+	uint16_t crc, calc_crc;
+
+	if (len < UBIFS_LPT_CRC_BYTES + (UBIFS_LPT_TYPE_BITS + 7) / 8)
+		return 0;
+	node_type = ubifs_unpack_bits(c, &addr, &pos, UBIFS_LPT_TYPE_BITS);
+	if (node_type == UBIFS_LPT_NOT_A_NODE)
+		return 0;
+	node_len = get_lpt_node_len(c, node_type);
+	if (!node_len || node_len > len)
+		return 0;
+	pos = 0;
+	addr = buf;
+	crc = ubifs_unpack_bits(c, &addr, &pos, UBIFS_LPT_CRC_BITS);
+	calc_crc = crc16(-1, buf + UBIFS_LPT_CRC_BYTES,
+			 node_len - UBIFS_LPT_CRC_BYTES);
+	if (crc != calc_crc)
+		return 0;
+	return 1;
+}
+
+/**
+ * lpt_gc_lnum - garbage collect a LPT LEB.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number to garbage collect
+ *
+ * LPT garbage collection is used only for the "big" LPT model
+ * (c->big_lpt == 1).  Garbage collection simply involves marking all the nodes
+ * in the LEB being garbage-collected as dirty.  The dirty nodes are written
+ * next commit, after which the LEB is free to be reused.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int lpt_gc_lnum(struct ubifs_info *c, int lnum)
+{
+	int err, len = c->leb_size, node_type, node_num, node_len, offs;
+	void *buf = c->lpt_buf;
+
+	dbg_lp("LEB %d", lnum);
+
+	err = ubifs_leb_read(c, lnum, buf, 0, c->leb_size, 1);
+	if (err)
+		return err;
+
+	while (1) {
+		if (!is_a_node(c, buf, len)) {
+			int pad_len;
+
+			pad_len = get_pad_len(c, buf, len);
+			if (pad_len) {
+				buf += pad_len;
+				len -= pad_len;
+				continue;
+			}
+			return 0;
+		}
+		node_type = get_lpt_node_type(c, buf, &node_num);
+		node_len = get_lpt_node_len(c, node_type);
+		offs = c->leb_size - len;
+		ubifs_assert(c, node_len != 0);
+		mutex_lock(&c->lp_mutex);
+		err = make_node_dirty(c, node_type, node_num, lnum, offs);
+		mutex_unlock(&c->lp_mutex);
+		if (err)
+			return err;
+		buf += node_len;
+		len -= node_len;
+	}
+	return 0;
+}
+
+/**
+ * lpt_gc - LPT garbage collection.
+ * @c: UBIFS file-system description object
+ *
+ * Select a LPT LEB for LPT garbage collection and call 'lpt_gc_lnum()'.
+ * Returns %0 on success and a negative error code on failure.
+ */
+static int lpt_gc(struct ubifs_info *c)
+{
+	int i, lnum = -1, dirty = 0;
+
+	mutex_lock(&c->lp_mutex);
+	for (i = 0; i < c->lpt_lebs; i++) {
+		ubifs_assert(c, !c->ltab[i].tgc);
+		if (i + c->lpt_first == c->nhead_lnum ||
+		    c->ltab[i].free + c->ltab[i].dirty == c->leb_size)
+			continue;
+		if (c->ltab[i].dirty > dirty) {
+			dirty = c->ltab[i].dirty;
+			lnum = i + c->lpt_first;
+		}
+	}
+	mutex_unlock(&c->lp_mutex);
+	if (lnum == -1)
+		return -ENOSPC;
+	return lpt_gc_lnum(c, lnum);
+}
+
+/**
+ * ubifs_lpt_start_commit - UBIFS commit starts.
+ * @c: the UBIFS file-system description object
+ *
+ * This function has to be called when UBIFS starts the commit operation.
+ * This function "freezes" all currently dirty LEB properties and does not
+ * change them anymore. Further changes are saved and tracked separately
+ * because they are not part of this commit. This function returns zero in case
+ * of success and a negative error code in case of failure.
+ */
+int ubifs_lpt_start_commit(struct ubifs_info *c)
+{
+	int err, cnt;
+
+	dbg_lp("");
+
+	mutex_lock(&c->lp_mutex);
+	err = dbg_chk_lpt_free_spc(c);
+	if (err)
+		goto out;
+	err = dbg_check_ltab(c);
+	if (err)
+		goto out;
+
+	if (c->check_lpt_free) {
+		/*
+		 * We ensure there is enough free space in
+		 * ubifs_lpt_post_commit() by marking nodes dirty. That
+		 * information is lost when we unmount, so we also need
+		 * to check free space once after mounting also.
+		 */
+		c->check_lpt_free = 0;
+		while (need_write_all(c)) {
+			mutex_unlock(&c->lp_mutex);
+			err = lpt_gc(c);
+			if (err)
+				return err;
+			mutex_lock(&c->lp_mutex);
+		}
+	}
+
+	lpt_tgc_start(c);
+
+	if (!c->dirty_pn_cnt) {
+		dbg_cmt("no cnodes to commit");
+		err = 0;
+		goto out;
+	}
+
+	if (!c->big_lpt && need_write_all(c)) {
+		/* If needed, write everything */
+		err = make_tree_dirty(c);
+		if (err)
+			goto out;
+		lpt_tgc_start(c);
+	}
+
+	if (c->big_lpt)
+		populate_lsave(c);
+
+	cnt = get_cnodes_to_commit(c);
+	ubifs_assert(c, cnt != 0);
+
+	err = layout_cnodes(c);
+	if (err)
+		goto out;
+
+	err = ubifs_lpt_calc_hash(c, c->mst_node->hash_lpt);
+	if (err)
+		goto out;
+
+	/* Copy the LPT's own lprops for end commit to write */
+	memcpy(c->ltab_cmt, c->ltab,
+	       sizeof(struct ubifs_lpt_lprops) * c->lpt_lebs);
+	c->lpt_drty_flgs &= ~(LTAB_DIRTY | LSAVE_DIRTY);
+
+out:
+	mutex_unlock(&c->lp_mutex);
+	return err;
+}
+
+/**
+ * free_obsolete_cnodes - free obsolete cnodes for commit end.
+ * @c: UBIFS file-system description object
+ */
+static void free_obsolete_cnodes(struct ubifs_info *c)
+{
+	struct ubifs_cnode *cnode, *cnext;
+
+	cnext = c->lpt_cnext;
+	if (!cnext)
+		return;
+	do {
+		cnode = cnext;
+		cnext = cnode->cnext;
+		if (test_bit(OBSOLETE_CNODE, &cnode->flags))
+			kfree(cnode);
+		else
+			cnode->cnext = NULL;
+	} while (cnext != c->lpt_cnext);
+	c->lpt_cnext = NULL;
+}
+
+/**
+ * ubifs_lpt_end_commit - finish the commit operation.
+ * @c: the UBIFS file-system description object
+ *
+ * This function has to be called when the commit operation finishes. It
+ * flushes the changes which were "frozen" by 'ubifs_lprops_start_commit()' to
+ * the media. Returns zero in case of success and a negative error code in case
+ * of failure.
+ */
+int ubifs_lpt_end_commit(struct ubifs_info *c)
+{
+	int err;
+
+	dbg_lp("");
+
+	if (!c->lpt_cnext)
+		return 0;
+
+	err = write_cnodes(c);
+	if (err)
+		return err;
+
+	mutex_lock(&c->lp_mutex);
+	free_obsolete_cnodes(c);
+	mutex_unlock(&c->lp_mutex);
+
+	return 0;
+}
+
+/**
+ * ubifs_lpt_post_commit - post commit LPT trivial GC and LPT GC.
+ * @c: UBIFS file-system description object
+ *
+ * LPT trivial GC is completed after a commit. Also LPT GC is done after a
+ * commit for the "big" LPT model.
+ */
+int ubifs_lpt_post_commit(struct ubifs_info *c)
+{
+	int err;
+
+	mutex_lock(&c->lp_mutex);
+	err = lpt_tgc_end(c);
+	if (err)
+		goto out;
+	if (c->big_lpt)
+		while (need_write_all(c)) {
+			mutex_unlock(&c->lp_mutex);
+			err = lpt_gc(c);
+			if (err)
+				return err;
+			mutex_lock(&c->lp_mutex);
+		}
+out:
+	mutex_unlock(&c->lp_mutex);
+	return err;
+}
+
+/**
+ * first_nnode - find the first nnode in memory.
+ * @c: UBIFS file-system description object
+ * @hght: height of tree where nnode found is returned here
+ *
+ * This function returns a pointer to the nnode found or %NULL if no nnode is
+ * found. This function is a helper to 'ubifs_lpt_free()'.
+ */
+static struct ubifs_nnode *first_nnode(struct ubifs_info *c, int *hght)
+{
+	struct ubifs_nnode *nnode;
+	int h, i, found;
+
+	nnode = c->nroot;
+	*hght = 0;
+	if (!nnode)
+		return NULL;
+	for (h = 1; h < c->lpt_hght; h++) {
+		found = 0;
+		for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+			if (nnode->nbranch[i].nnode) {
+				found = 1;
+				nnode = nnode->nbranch[i].nnode;
+				*hght = h;
+				break;
+			}
+		}
+		if (!found)
+			break;
+	}
+	return nnode;
+}
+
+/**
+ * next_nnode - find the next nnode in memory.
+ * @c: UBIFS file-system description object
+ * @nnode: nnode from which to start.
+ * @hght: height of tree where nnode is, is passed and returned here
+ *
+ * This function returns a pointer to the nnode found or %NULL if no nnode is
+ * found. This function is a helper to 'ubifs_lpt_free()'.
+ */
+static struct ubifs_nnode *next_nnode(struct ubifs_info *c,
+				      struct ubifs_nnode *nnode, int *hght)
+{
+	struct ubifs_nnode *parent;
+	int iip, h, i, found;
+
+	parent = nnode->parent;
+	if (!parent)
+		return NULL;
+	if (nnode->iip == UBIFS_LPT_FANOUT - 1) {
+		*hght -= 1;
+		return parent;
+	}
+	for (iip = nnode->iip + 1; iip < UBIFS_LPT_FANOUT; iip++) {
+		nnode = parent->nbranch[iip].nnode;
+		if (nnode)
+			break;
+	}
+	if (!nnode) {
+		*hght -= 1;
+		return parent;
+	}
+	for (h = *hght + 1; h < c->lpt_hght; h++) {
+		found = 0;
+		for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+			if (nnode->nbranch[i].nnode) {
+				found = 1;
+				nnode = nnode->nbranch[i].nnode;
+				*hght = h;
+				break;
+			}
+		}
+		if (!found)
+			break;
+	}
+	return nnode;
+}
+
+/**
+ * ubifs_lpt_free - free resources owned by the LPT.
+ * @c: UBIFS file-system description object
+ * @wr_only: free only resources used for writing
+ */
+void ubifs_lpt_free(struct ubifs_info *c, int wr_only)
+{
+	struct ubifs_nnode *nnode;
+	int i, hght;
+
+	/* Free write-only things first */
+
+	free_obsolete_cnodes(c); /* Leftover from a failed commit */
+
+	vfree(c->ltab_cmt);
+	c->ltab_cmt = NULL;
+	vfree(c->lpt_buf);
+	c->lpt_buf = NULL;
+	kfree(c->lsave);
+	c->lsave = NULL;
+
+	if (wr_only)
+		return;
+
+	/* Now free the rest */
+
+	nnode = first_nnode(c, &hght);
+	while (nnode) {
+		for (i = 0; i < UBIFS_LPT_FANOUT; i++)
+			kfree(nnode->nbranch[i].nnode);
+		nnode = next_nnode(c, nnode, &hght);
+	}
+	for (i = 0; i < LPROPS_HEAP_CNT; i++)
+		kfree(c->lpt_heap[i].arr);
+	kfree(c->dirty_idx.arr);
+	kfree(c->nroot);
+	vfree(c->ltab);
+	kfree(c->lpt_nod_buf);
+}
+
+/*
+ * Everything below is related to debugging.
+ */
+
+/**
+ * dbg_is_all_ff - determine if a buffer contains only 0xFF bytes.
+ * @buf: buffer
+ * @len: buffer length
+ */
+static int dbg_is_all_ff(uint8_t *buf, int len)
+{
+	int i;
+
+	for (i = 0; i < len; i++)
+		if (buf[i] != 0xff)
+			return 0;
+	return 1;
+}
+
+/**
+ * dbg_is_nnode_dirty - determine if a nnode is dirty.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB number where nnode was written
+ * @offs: offset where nnode was written
+ */
+static int dbg_is_nnode_dirty(struct ubifs_info *c, int lnum, int offs)
+{
+	struct ubifs_nnode *nnode;
+	int hght;
+
+	/* Entire tree is in memory so first_nnode / next_nnode are OK */
+	nnode = first_nnode(c, &hght);
+	for (; nnode; nnode = next_nnode(c, nnode, &hght)) {
+		struct ubifs_nbranch *branch;
+
+		cond_resched();
+		if (nnode->parent) {
+			branch = &nnode->parent->nbranch[nnode->iip];
+			if (branch->lnum != lnum || branch->offs != offs)
+				continue;
+			if (test_bit(DIRTY_CNODE, &nnode->flags))
+				return 1;
+			return 0;
+		} else {
+			if (c->lpt_lnum != lnum || c->lpt_offs != offs)
+				continue;
+			if (test_bit(DIRTY_CNODE, &nnode->flags))
+				return 1;
+			return 0;
+		}
+	}
+	return 1;
+}
+
+/**
+ * dbg_is_pnode_dirty - determine if a pnode is dirty.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB number where pnode was written
+ * @offs: offset where pnode was written
+ */
+static int dbg_is_pnode_dirty(struct ubifs_info *c, int lnum, int offs)
+{
+	int i, cnt;
+
+	cnt = DIV_ROUND_UP(c->main_lebs, UBIFS_LPT_FANOUT);
+	for (i = 0; i < cnt; i++) {
+		struct ubifs_pnode *pnode;
+		struct ubifs_nbranch *branch;
+
+		cond_resched();
+		pnode = ubifs_pnode_lookup(c, i);
+		if (IS_ERR(pnode))
+			return PTR_ERR(pnode);
+		branch = &pnode->parent->nbranch[pnode->iip];
+		if (branch->lnum != lnum || branch->offs != offs)
+			continue;
+		if (test_bit(DIRTY_CNODE, &pnode->flags))
+			return 1;
+		return 0;
+	}
+	return 1;
+}
+
+/**
+ * dbg_is_ltab_dirty - determine if a ltab node is dirty.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB number where ltab node was written
+ * @offs: offset where ltab node was written
+ */
+static int dbg_is_ltab_dirty(struct ubifs_info *c, int lnum, int offs)
+{
+	if (lnum != c->ltab_lnum || offs != c->ltab_offs)
+		return 1;
+	return (c->lpt_drty_flgs & LTAB_DIRTY) != 0;
+}
+
+/**
+ * dbg_is_lsave_dirty - determine if a lsave node is dirty.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB number where lsave node was written
+ * @offs: offset where lsave node was written
+ */
+static int dbg_is_lsave_dirty(struct ubifs_info *c, int lnum, int offs)
+{
+	if (lnum != c->lsave_lnum || offs != c->lsave_offs)
+		return 1;
+	return (c->lpt_drty_flgs & LSAVE_DIRTY) != 0;
+}
+
+/**
+ * dbg_is_node_dirty - determine if a node is dirty.
+ * @c: the UBIFS file-system description object
+ * @node_type: node type
+ * @lnum: LEB number where node was written
+ * @offs: offset where node was written
+ */
+static int dbg_is_node_dirty(struct ubifs_info *c, int node_type, int lnum,
+			     int offs)
+{
+	switch (node_type) {
+	case UBIFS_LPT_NNODE:
+		return dbg_is_nnode_dirty(c, lnum, offs);
+	case UBIFS_LPT_PNODE:
+		return dbg_is_pnode_dirty(c, lnum, offs);
+	case UBIFS_LPT_LTAB:
+		return dbg_is_ltab_dirty(c, lnum, offs);
+	case UBIFS_LPT_LSAVE:
+		return dbg_is_lsave_dirty(c, lnum, offs);
+	}
+	return 1;
+}
+
+/**
+ * dbg_check_ltab_lnum - check the ltab for a LPT LEB number.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB number where node was written
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int dbg_check_ltab_lnum(struct ubifs_info *c, int lnum)
+{
+	int err, len = c->leb_size, dirty = 0, node_type, node_num, node_len;
+	int ret;
+	void *buf, *p;
+
+	if (!dbg_is_chk_lprops(c))
+		return 0;
+
+	buf = p = __vmalloc(c->leb_size, GFP_NOFS);
+	if (!buf) {
+		ubifs_err(c, "cannot allocate memory for ltab checking");
+		return 0;
+	}
+
+	dbg_lp("LEB %d", lnum);
+
+	err = ubifs_leb_read(c, lnum, buf, 0, c->leb_size, 1);
+	if (err)
+		goto out;
+
+	while (1) {
+		if (!is_a_node(c, p, len)) {
+			int i, pad_len;
+
+			pad_len = get_pad_len(c, p, len);
+			if (pad_len) {
+				p += pad_len;
+				len -= pad_len;
+				dirty += pad_len;
+				continue;
+			}
+			if (!dbg_is_all_ff(p, len)) {
+				ubifs_err(c, "invalid empty space in LEB %d at %d",
+					  lnum, c->leb_size - len);
+				err = -EINVAL;
+			}
+			i = lnum - c->lpt_first;
+			if (len != c->ltab[i].free) {
+				ubifs_err(c, "invalid free space in LEB %d (free %d, expected %d)",
+					  lnum, len, c->ltab[i].free);
+				err = -EINVAL;
+			}
+			if (dirty != c->ltab[i].dirty) {
+				ubifs_err(c, "invalid dirty space in LEB %d (dirty %d, expected %d)",
+					  lnum, dirty, c->ltab[i].dirty);
+				err = -EINVAL;
+			}
+			goto out;
+		}
+		node_type = get_lpt_node_type(c, p, &node_num);
+		node_len = get_lpt_node_len(c, node_type);
+		ret = dbg_is_node_dirty(c, node_type, lnum, c->leb_size - len);
+		if (ret == 1)
+			dirty += node_len;
+		p += node_len;
+		len -= node_len;
+	}
+
+	err = 0;
+out:
+	vfree(buf);
+	return err;
+}
+
+/**
+ * dbg_check_ltab - check the free and dirty space in the ltab.
+ * @c: the UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int dbg_check_ltab(struct ubifs_info *c)
+{
+	int lnum, err, i, cnt;
+
+	if (!dbg_is_chk_lprops(c))
+		return 0;
+
+	/* Bring the entire tree into memory */
+	cnt = DIV_ROUND_UP(c->main_lebs, UBIFS_LPT_FANOUT);
+	for (i = 0; i < cnt; i++) {
+		struct ubifs_pnode *pnode;
+
+		pnode = ubifs_pnode_lookup(c, i);
+		if (IS_ERR(pnode))
+			return PTR_ERR(pnode);
+		cond_resched();
+	}
+
+	/* Check nodes */
+	err = dbg_check_lpt_nodes(c, (struct ubifs_cnode *)c->nroot, 0, 0);
+	if (err)
+		return err;
+
+	/* Check each LEB */
+	for (lnum = c->lpt_first; lnum <= c->lpt_last; lnum++) {
+		err = dbg_check_ltab_lnum(c, lnum);
+		if (err) {
+			ubifs_err(c, "failed at LEB %d", lnum);
+			return err;
+		}
+	}
+
+	dbg_lp("succeeded");
+	return 0;
+}
+
+/**
+ * dbg_chk_lpt_free_spc - check LPT free space is enough to write entire LPT.
+ * @c: the UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int dbg_chk_lpt_free_spc(struct ubifs_info *c)
+{
+	long long free = 0;
+	int i;
+
+	if (!dbg_is_chk_lprops(c))
+		return 0;
+
+	for (i = 0; i < c->lpt_lebs; i++) {
+		if (c->ltab[i].tgc || c->ltab[i].cmt)
+			continue;
+		if (i + c->lpt_first == c->nhead_lnum)
+			free += c->leb_size - c->nhead_offs;
+		else if (c->ltab[i].free == c->leb_size)
+			free += c->leb_size;
+	}
+	if (free < c->lpt_sz) {
+		ubifs_err(c, "LPT space error: free %lld lpt_sz %lld",
+			  free, c->lpt_sz);
+		ubifs_dump_lpt_info(c);
+		ubifs_dump_lpt_lebs(c);
+		dump_stack();
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/**
+ * dbg_chk_lpt_sz - check LPT does not write more than LPT size.
+ * @c: the UBIFS file-system description object
+ * @action: what to do
+ * @len: length written
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ * The @action argument may be one of:
+ *   o %0 - LPT debugging checking starts, initialize debugging variables;
+ *   o %1 - wrote an LPT node, increase LPT size by @len bytes;
+ *   o %2 - switched to a different LEB and wasted @len bytes;
+ *   o %3 - check that we've written the right number of bytes.
+ *   o %4 - wasted @len bytes;
+ */
+int dbg_chk_lpt_sz(struct ubifs_info *c, int action, int len)
+{
+	struct ubifs_debug_info *d = c->dbg;
+	long long chk_lpt_sz, lpt_sz;
+	int err = 0;
+
+	if (!dbg_is_chk_lprops(c))
+		return 0;
+
+	switch (action) {
+	case 0:
+		d->chk_lpt_sz = 0;
+		d->chk_lpt_sz2 = 0;
+		d->chk_lpt_lebs = 0;
+		d->chk_lpt_wastage = 0;
+		if (c->dirty_pn_cnt > c->pnode_cnt) {
+			ubifs_err(c, "dirty pnodes %d exceed max %d",
+				  c->dirty_pn_cnt, c->pnode_cnt);
+			err = -EINVAL;
+		}
+		if (c->dirty_nn_cnt > c->nnode_cnt) {
+			ubifs_err(c, "dirty nnodes %d exceed max %d",
+				  c->dirty_nn_cnt, c->nnode_cnt);
+			err = -EINVAL;
+		}
+		return err;
+	case 1:
+		d->chk_lpt_sz += len;
+		return 0;
+	case 2:
+		d->chk_lpt_sz += len;
+		d->chk_lpt_wastage += len;
+		d->chk_lpt_lebs += 1;
+		return 0;
+	case 3:
+		chk_lpt_sz = c->leb_size;
+		chk_lpt_sz *= d->chk_lpt_lebs;
+		chk_lpt_sz += len - c->nhead_offs;
+		if (d->chk_lpt_sz != chk_lpt_sz) {
+			ubifs_err(c, "LPT wrote %lld but space used was %lld",
+				  d->chk_lpt_sz, chk_lpt_sz);
+			err = -EINVAL;
+		}
+		if (d->chk_lpt_sz > c->lpt_sz) {
+			ubifs_err(c, "LPT wrote %lld but lpt_sz is %lld",
+				  d->chk_lpt_sz, c->lpt_sz);
+			err = -EINVAL;
+		}
+		if (d->chk_lpt_sz2 && d->chk_lpt_sz != d->chk_lpt_sz2) {
+			ubifs_err(c, "LPT layout size %lld but wrote %lld",
+				  d->chk_lpt_sz, d->chk_lpt_sz2);
+			err = -EINVAL;
+		}
+		if (d->chk_lpt_sz2 && d->new_nhead_offs != len) {
+			ubifs_err(c, "LPT new nhead offs: expected %d was %d",
+				  d->new_nhead_offs, len);
+			err = -EINVAL;
+		}
+		lpt_sz = (long long)c->pnode_cnt * c->pnode_sz;
+		lpt_sz += (long long)c->nnode_cnt * c->nnode_sz;
+		lpt_sz += c->ltab_sz;
+		if (c->big_lpt)
+			lpt_sz += c->lsave_sz;
+		if (d->chk_lpt_sz - d->chk_lpt_wastage > lpt_sz) {
+			ubifs_err(c, "LPT chk_lpt_sz %lld + waste %lld exceeds %lld",
+				  d->chk_lpt_sz, d->chk_lpt_wastage, lpt_sz);
+			err = -EINVAL;
+		}
+		if (err) {
+			ubifs_dump_lpt_info(c);
+			ubifs_dump_lpt_lebs(c);
+			dump_stack();
+		}
+		d->chk_lpt_sz2 = d->chk_lpt_sz;
+		d->chk_lpt_sz = 0;
+		d->chk_lpt_wastage = 0;
+		d->chk_lpt_lebs = 0;
+		d->new_nhead_offs = len;
+		return err;
+	case 4:
+		d->chk_lpt_sz += len;
+		d->chk_lpt_wastage += len;
+		return 0;
+	default:
+		return -EINVAL;
+	}
+}
+
+/**
+ * dump_lpt_leb - dump an LPT LEB.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number to dump
+ *
+ * This function dumps an LEB from LPT area. Nodes in this area are very
+ * different to nodes in the main area (e.g., they do not have common headers,
+ * they do not have 8-byte alignments, etc), so we have a separate function to
+ * dump LPT area LEBs. Note, LPT has to be locked by the caller.
+ */
+static void dump_lpt_leb(const struct ubifs_info *c, int lnum)
+{
+	int err, len = c->leb_size, node_type, node_num, node_len, offs;
+	void *buf, *p;
+
+	pr_err("(pid %d) start dumping LEB %d\n", current->pid, lnum);
+	buf = p = __vmalloc(c->leb_size, GFP_NOFS);
+	if (!buf) {
+		ubifs_err(c, "cannot allocate memory to dump LPT");
+		return;
+	}
+
+	err = ubifs_leb_read(c, lnum, buf, 0, c->leb_size, 1);
+	if (err)
+		goto out;
+
+	while (1) {
+		offs = c->leb_size - len;
+		if (!is_a_node(c, p, len)) {
+			int pad_len;
+
+			pad_len = get_pad_len(c, p, len);
+			if (pad_len) {
+				pr_err("LEB %d:%d, pad %d bytes\n",
+				       lnum, offs, pad_len);
+				p += pad_len;
+				len -= pad_len;
+				continue;
+			}
+			if (len)
+				pr_err("LEB %d:%d, free %d bytes\n",
+				       lnum, offs, len);
+			break;
+		}
+
+		node_type = get_lpt_node_type(c, p, &node_num);
+		switch (node_type) {
+		case UBIFS_LPT_PNODE:
+		{
+			node_len = c->pnode_sz;
+			if (c->big_lpt)
+				pr_err("LEB %d:%d, pnode num %d\n",
+				       lnum, offs, node_num);
+			else
+				pr_err("LEB %d:%d, pnode\n", lnum, offs);
+			break;
+		}
+		case UBIFS_LPT_NNODE:
+		{
+			int i;
+			struct ubifs_nnode nnode;
+
+			node_len = c->nnode_sz;
+			if (c->big_lpt)
+				pr_err("LEB %d:%d, nnode num %d, ",
+				       lnum, offs, node_num);
+			else
+				pr_err("LEB %d:%d, nnode, ",
+				       lnum, offs);
+			err = ubifs_unpack_nnode(c, p, &nnode);
+			if (err) {
+				pr_err("failed to unpack_node, error %d\n",
+				       err);
+				break;
+			}
+			for (i = 0; i < UBIFS_LPT_FANOUT; i++) {
+				pr_cont("%d:%d", nnode.nbranch[i].lnum,
+				       nnode.nbranch[i].offs);
+				if (i != UBIFS_LPT_FANOUT - 1)
+					pr_cont(", ");
+			}
+			pr_cont("\n");
+			break;
+		}
+		case UBIFS_LPT_LTAB:
+			node_len = c->ltab_sz;
+			pr_err("LEB %d:%d, ltab\n", lnum, offs);
+			break;
+		case UBIFS_LPT_LSAVE:
+			node_len = c->lsave_sz;
+			pr_err("LEB %d:%d, lsave len\n", lnum, offs);
+			break;
+		default:
+			ubifs_err(c, "LPT node type %d not recognized", node_type);
+			goto out;
+		}
+
+		p += node_len;
+		len -= node_len;
+	}
+
+	pr_err("(pid %d) finish dumping LEB %d\n", current->pid, lnum);
+out:
+	vfree(buf);
+	return;
+}
+
+/**
+ * ubifs_dump_lpt_lebs - dump LPT lebs.
+ * @c: UBIFS file-system description object
+ *
+ * This function dumps all LPT LEBs. The caller has to make sure the LPT is
+ * locked.
+ */
+void ubifs_dump_lpt_lebs(const struct ubifs_info *c)
+{
+	int i;
+
+	pr_err("(pid %d) start dumping all LPT LEBs\n", current->pid);
+	for (i = 0; i < c->lpt_lebs; i++)
+		dump_lpt_leb(c, i + c->lpt_first);
+	pr_err("(pid %d) finish dumping all LPT LEBs\n", current->pid);
+}
+
+/**
+ * dbg_populate_lsave - debugging version of 'populate_lsave()'
+ * @c: UBIFS file-system description object
+ *
+ * This is a debugging version for 'populate_lsave()' which populates lsave
+ * with random LEBs instead of useful LEBs, which is good for test coverage.
+ * Returns zero if lsave has not been populated (this debugging feature is
+ * disabled) an non-zero if lsave has been populated.
+ */
+static int dbg_populate_lsave(struct ubifs_info *c)
+{
+	struct ubifs_lprops *lprops;
+	struct ubifs_lpt_heap *heap;
+	int i;
+
+	if (!dbg_is_chk_gen(c))
+		return 0;
+	if (get_random_u32_below(4))
+		return 0;
+
+	for (i = 0; i < c->lsave_cnt; i++)
+		c->lsave[i] = c->main_first;
+
+	list_for_each_entry(lprops, &c->empty_list, list)
+		c->lsave[get_random_u32_below(c->lsave_cnt)] = lprops->lnum;
+	list_for_each_entry(lprops, &c->freeable_list, list)
+		c->lsave[get_random_u32_below(c->lsave_cnt)] = lprops->lnum;
+	list_for_each_entry(lprops, &c->frdi_idx_list, list)
+		c->lsave[get_random_u32_below(c->lsave_cnt)] = lprops->lnum;
+
+	heap = &c->lpt_heap[LPROPS_DIRTY_IDX - 1];
+	for (i = 0; i < heap->cnt; i++)
+		c->lsave[get_random_u32_below(c->lsave_cnt)] = heap->arr[i]->lnum;
+	heap = &c->lpt_heap[LPROPS_DIRTY - 1];
+	for (i = 0; i < heap->cnt; i++)
+		c->lsave[get_random_u32_below(c->lsave_cnt)] = heap->arr[i]->lnum;
+	heap = &c->lpt_heap[LPROPS_FREE - 1];
+	for (i = 0; i < heap->cnt; i++)
+		c->lsave[get_random_u32_below(c->lsave_cnt)] = heap->arr[i]->lnum;
+
+	return 1;
+}
diff --git a/ubifs-utils/libubifs/master.c b/ubifs-utils/libubifs/master.c
new file mode 100644
index 00000000..7adc37c1
--- /dev/null
+++ b/ubifs-utils/libubifs/master.c
@@ -0,0 +1,473 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ */
+
+/* This file implements reading and writing the master node */
+
+#include "ubifs.h"
+
+/**
+ * ubifs_compare_master_node - compare two UBIFS master nodes
+ * @c: UBIFS file-system description object
+ * @m1: the first node
+ * @m2: the second node
+ *
+ * This function compares two UBIFS master nodes. Returns 0 if they are equal
+ * and nonzero if not.
+ */
+int ubifs_compare_master_node(struct ubifs_info *c, void *m1, void *m2)
+{
+	int ret;
+	int behind;
+	int hmac_offs = offsetof(struct ubifs_mst_node, hmac);
+
+	/*
+	 * Do not compare the common node header since the sequence number and
+	 * hence the CRC are different.
+	 */
+	ret = memcmp(m1 + UBIFS_CH_SZ, m2 + UBIFS_CH_SZ,
+		     hmac_offs - UBIFS_CH_SZ);
+	if (ret)
+		return ret;
+
+	/*
+	 * Do not compare the embedded HMAC as well which also must be different
+	 * due to the different common node header.
+	 */
+	behind = hmac_offs + UBIFS_MAX_HMAC_LEN;
+
+	if (UBIFS_MST_NODE_SZ > behind)
+		return memcmp(m1 + behind, m2 + behind, UBIFS_MST_NODE_SZ - behind);
+
+	return 0;
+}
+
+/* mst_node_check_hash - Check hash of a master node
+ * @c: UBIFS file-system description object
+ * @mst: The master node
+ * @expected: The expected hash of the master node
+ *
+ * This checks the hash of a master node against a given expected hash.
+ * Note that we have two master nodes on a UBIFS image which have different
+ * sequence numbers and consequently different CRCs. To be able to match
+ * both master nodes we exclude the common node header containing the sequence
+ * number and CRC from the hash.
+ *
+ * Returns 0 if the hashes are equal, a negative error code otherwise.
+ */
+static int mst_node_check_hash(const struct ubifs_info *c,
+			       const struct ubifs_mst_node *mst,
+			       const u8 *expected)
+{
+	u8 calc[UBIFS_MAX_HASH_LEN];
+	const void *node = mst;
+
+	crypto_shash_tfm_digest(c->hash_tfm, node + sizeof(struct ubifs_ch),
+				UBIFS_MST_NODE_SZ - sizeof(struct ubifs_ch),
+				calc);
+
+	if (ubifs_check_hash(c, expected, calc))
+		return -EPERM;
+
+	return 0;
+}
+
+/**
+ * scan_for_master - search the valid master node.
+ * @c: UBIFS file-system description object
+ *
+ * This function scans the master node LEBs and search for the latest master
+ * node. Returns zero in case of success, %-EUCLEAN if there master area is
+ * corrupted and requires recovery, and a negative error code in case of
+ * failure.
+ */
+static int scan_for_master(struct ubifs_info *c)
+{
+	struct ubifs_scan_leb *sleb;
+	struct ubifs_scan_node *snod;
+	int lnum, offs = 0, nodes_cnt, err;
+
+	lnum = UBIFS_MST_LNUM;
+
+	sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
+	if (IS_ERR(sleb))
+		return PTR_ERR(sleb);
+	nodes_cnt = sleb->nodes_cnt;
+	if (nodes_cnt > 0) {
+		snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
+				  list);
+		if (snod->type != UBIFS_MST_NODE)
+			goto out_dump;
+		memcpy(c->mst_node, snod->node, snod->len);
+		offs = snod->offs;
+	}
+	ubifs_scan_destroy(sleb);
+
+	lnum += 1;
+
+	sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
+	if (IS_ERR(sleb))
+		return PTR_ERR(sleb);
+	if (sleb->nodes_cnt != nodes_cnt)
+		goto out;
+	if (!sleb->nodes_cnt)
+		goto out;
+	snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node, list);
+	if (snod->type != UBIFS_MST_NODE)
+		goto out_dump;
+	if (snod->offs != offs)
+		goto out;
+	if (ubifs_compare_master_node(c, c->mst_node, snod->node))
+		goto out;
+
+	c->mst_offs = offs;
+	ubifs_scan_destroy(sleb);
+
+	if (!ubifs_authenticated(c))
+		return 0;
+
+	if (ubifs_hmac_zero(c, c->mst_node->hmac)) {
+		err = mst_node_check_hash(c, c->mst_node,
+					  c->sup_node->hash_mst);
+		if (err)
+			ubifs_err(c, "Failed to verify master node hash");
+	} else {
+		err = ubifs_node_verify_hmac(c, c->mst_node,
+					sizeof(struct ubifs_mst_node),
+					offsetof(struct ubifs_mst_node, hmac));
+		if (err)
+			ubifs_err(c, "Failed to verify master node HMAC");
+	}
+
+	if (err)
+		return -EPERM;
+
+	return 0;
+
+out:
+	ubifs_scan_destroy(sleb);
+	return -EUCLEAN;
+
+out_dump:
+	ubifs_err(c, "unexpected node type %d master LEB %d:%d",
+		  snod->type, lnum, snod->offs);
+	ubifs_scan_destroy(sleb);
+	return -EINVAL;
+}
+
+/**
+ * validate_master - validate master node.
+ * @c: UBIFS file-system description object
+ *
+ * This function validates data which was read from master node. Returns zero
+ * if the data is all right and %-EINVAL if not.
+ */
+static int validate_master(const struct ubifs_info *c)
+{
+	long long main_sz;
+	int err;
+
+	if (c->max_sqnum >= SQNUM_WATERMARK) {
+		err = 1;
+		goto out;
+	}
+
+	if (c->cmt_no >= c->max_sqnum) {
+		err = 2;
+		goto out;
+	}
+
+	if (c->highest_inum >= INUM_WATERMARK) {
+		err = 3;
+		goto out;
+	}
+
+	if (c->lhead_lnum < UBIFS_LOG_LNUM ||
+	    c->lhead_lnum >= UBIFS_LOG_LNUM + c->log_lebs ||
+	    c->lhead_offs < 0 || c->lhead_offs >= c->leb_size ||
+	    c->lhead_offs & (c->min_io_size - 1)) {
+		err = 4;
+		goto out;
+	}
+
+	if (c->zroot.lnum >= c->leb_cnt || c->zroot.lnum < c->main_first ||
+	    c->zroot.offs >= c->leb_size || c->zroot.offs & 7) {
+		err = 5;
+		goto out;
+	}
+
+	if (c->zroot.len < c->ranges[UBIFS_IDX_NODE].min_len ||
+	    c->zroot.len > c->ranges[UBIFS_IDX_NODE].max_len) {
+		err = 6;
+		goto out;
+	}
+
+	if (c->gc_lnum >= c->leb_cnt || c->gc_lnum < c->main_first) {
+		err = 7;
+		goto out;
+	}
+
+	if (c->ihead_lnum >= c->leb_cnt || c->ihead_lnum < c->main_first ||
+	    c->ihead_offs % c->min_io_size || c->ihead_offs < 0 ||
+	    c->ihead_offs > c->leb_size || c->ihead_offs & 7) {
+		err = 8;
+		goto out;
+	}
+
+	main_sz = (long long)c->main_lebs * c->leb_size;
+	if (c->bi.old_idx_sz & 7 || c->bi.old_idx_sz >= main_sz) {
+		err = 9;
+		goto out;
+	}
+
+	if (c->lpt_lnum < c->lpt_first || c->lpt_lnum > c->lpt_last ||
+	    c->lpt_offs < 0 || c->lpt_offs + c->nnode_sz > c->leb_size) {
+		err = 10;
+		goto out;
+	}
+
+	if (c->nhead_lnum < c->lpt_first || c->nhead_lnum > c->lpt_last ||
+	    c->nhead_offs < 0 || c->nhead_offs % c->min_io_size ||
+	    c->nhead_offs > c->leb_size) {
+		err = 11;
+		goto out;
+	}
+
+	if (c->ltab_lnum < c->lpt_first || c->ltab_lnum > c->lpt_last ||
+	    c->ltab_offs < 0 ||
+	    c->ltab_offs + c->ltab_sz > c->leb_size) {
+		err = 12;
+		goto out;
+	}
+
+	if (c->big_lpt && (c->lsave_lnum < c->lpt_first ||
+	    c->lsave_lnum > c->lpt_last || c->lsave_offs < 0 ||
+	    c->lsave_offs + c->lsave_sz > c->leb_size)) {
+		err = 13;
+		goto out;
+	}
+
+	if (c->lscan_lnum < c->main_first || c->lscan_lnum >= c->leb_cnt) {
+		err = 14;
+		goto out;
+	}
+
+	if (c->lst.empty_lebs < 0 || c->lst.empty_lebs > c->main_lebs - 2) {
+		err = 15;
+		goto out;
+	}
+
+	if (c->lst.idx_lebs < 0 || c->lst.idx_lebs > c->main_lebs - 1) {
+		err = 16;
+		goto out;
+	}
+
+	if (c->lst.total_free < 0 || c->lst.total_free > main_sz ||
+	    c->lst.total_free & 7) {
+		err = 17;
+		goto out;
+	}
+
+	if (c->lst.total_dirty < 0 || (c->lst.total_dirty & 7)) {
+		err = 18;
+		goto out;
+	}
+
+	if (c->lst.total_used < 0 || (c->lst.total_used & 7)) {
+		err = 19;
+		goto out;
+	}
+
+	if (c->lst.total_free + c->lst.total_dirty +
+	    c->lst.total_used > main_sz) {
+		err = 20;
+		goto out;
+	}
+
+	if (c->lst.total_dead + c->lst.total_dark +
+	    c->lst.total_used + c->bi.old_idx_sz > main_sz) {
+		err = 21;
+		goto out;
+	}
+
+	if (c->lst.total_dead < 0 ||
+	    c->lst.total_dead > c->lst.total_free + c->lst.total_dirty ||
+	    c->lst.total_dead & 7) {
+		err = 22;
+		goto out;
+	}
+
+	if (c->lst.total_dark < 0 ||
+	    c->lst.total_dark > c->lst.total_free + c->lst.total_dirty ||
+	    c->lst.total_dark & 7) {
+		err = 23;
+		goto out;
+	}
+
+	return 0;
+
+out:
+	ubifs_err(c, "bad master node at offset %d error %d", c->mst_offs, err);
+	ubifs_dump_node(c, c->mst_node, c->mst_node_alsz);
+	return -EINVAL;
+}
+
+/**
+ * ubifs_read_master - read master node.
+ * @c: UBIFS file-system description object
+ *
+ * This function finds and reads the master node during file-system mount. If
+ * the flash is empty, it creates default master node as well. Returns zero in
+ * case of success and a negative error code in case of failure.
+ */
+int ubifs_read_master(struct ubifs_info *c)
+{
+	int err, old_leb_cnt;
+
+	c->mst_node = kzalloc(c->mst_node_alsz, GFP_KERNEL);
+	if (!c->mst_node)
+		return -ENOMEM;
+
+	err = scan_for_master(c);
+	if (err) {
+		if (err == -EUCLEAN)
+			err = ubifs_recover_master_node(c);
+		if (err)
+			/*
+			 * Note, we do not free 'c->mst_node' here because the
+			 * unmount routine will take care of this.
+			 */
+			return err;
+	}
+
+	/* Make sure that the recovery flag is clear */
+	c->mst_node->flags &= cpu_to_le32(~UBIFS_MST_RCVRY);
+
+	c->max_sqnum       = le64_to_cpu(c->mst_node->ch.sqnum);
+	c->highest_inum    = le64_to_cpu(c->mst_node->highest_inum);
+	c->cmt_no          = le64_to_cpu(c->mst_node->cmt_no);
+	c->zroot.lnum      = le32_to_cpu(c->mst_node->root_lnum);
+	c->zroot.offs      = le32_to_cpu(c->mst_node->root_offs);
+	c->zroot.len       = le32_to_cpu(c->mst_node->root_len);
+	c->lhead_lnum      = le32_to_cpu(c->mst_node->log_lnum);
+	c->gc_lnum         = le32_to_cpu(c->mst_node->gc_lnum);
+	c->ihead_lnum      = le32_to_cpu(c->mst_node->ihead_lnum);
+	c->ihead_offs      = le32_to_cpu(c->mst_node->ihead_offs);
+	c->bi.old_idx_sz   = le64_to_cpu(c->mst_node->index_size);
+	c->lpt_lnum        = le32_to_cpu(c->mst_node->lpt_lnum);
+	c->lpt_offs        = le32_to_cpu(c->mst_node->lpt_offs);
+	c->nhead_lnum      = le32_to_cpu(c->mst_node->nhead_lnum);
+	c->nhead_offs      = le32_to_cpu(c->mst_node->nhead_offs);
+	c->ltab_lnum       = le32_to_cpu(c->mst_node->ltab_lnum);
+	c->ltab_offs       = le32_to_cpu(c->mst_node->ltab_offs);
+	c->lsave_lnum      = le32_to_cpu(c->mst_node->lsave_lnum);
+	c->lsave_offs      = le32_to_cpu(c->mst_node->lsave_offs);
+	c->lscan_lnum      = le32_to_cpu(c->mst_node->lscan_lnum);
+	c->lst.empty_lebs  = le32_to_cpu(c->mst_node->empty_lebs);
+	c->lst.idx_lebs    = le32_to_cpu(c->mst_node->idx_lebs);
+	old_leb_cnt        = le32_to_cpu(c->mst_node->leb_cnt);
+	c->lst.total_free  = le64_to_cpu(c->mst_node->total_free);
+	c->lst.total_dirty = le64_to_cpu(c->mst_node->total_dirty);
+	c->lst.total_used  = le64_to_cpu(c->mst_node->total_used);
+	c->lst.total_dead  = le64_to_cpu(c->mst_node->total_dead);
+	c->lst.total_dark  = le64_to_cpu(c->mst_node->total_dark);
+
+	ubifs_copy_hash(c, c->mst_node->hash_root_idx, c->zroot.hash);
+
+	c->calc_idx_sz = c->bi.old_idx_sz;
+
+	if (c->mst_node->flags & cpu_to_le32(UBIFS_MST_NO_ORPHS))
+		c->no_orphs = 1;
+
+	if (old_leb_cnt != c->leb_cnt) {
+		/* The file system has been resized */
+		int growth = c->leb_cnt - old_leb_cnt;
+
+		if (c->leb_cnt < old_leb_cnt ||
+		    c->leb_cnt < UBIFS_MIN_LEB_CNT) {
+			ubifs_err(c, "bad leb_cnt on master node");
+			ubifs_dump_node(c, c->mst_node, c->mst_node_alsz);
+			return -EINVAL;
+		}
+
+		dbg_mnt("Auto resizing (master) from %d LEBs to %d LEBs",
+			old_leb_cnt, c->leb_cnt);
+		c->lst.empty_lebs += growth;
+		c->lst.total_free += growth * (long long)c->leb_size;
+		c->lst.total_dark += growth * (long long)c->dark_wm;
+
+		/*
+		 * Reflect changes back onto the master node. N.B. the master
+		 * node gets written immediately whenever mounting (or
+		 * remounting) in read-write mode, so we do not need to write it
+		 * here.
+		 */
+		c->mst_node->leb_cnt = cpu_to_le32(c->leb_cnt);
+		c->mst_node->empty_lebs = cpu_to_le32(c->lst.empty_lebs);
+		c->mst_node->total_free = cpu_to_le64(c->lst.total_free);
+		c->mst_node->total_dark = cpu_to_le64(c->lst.total_dark);
+	}
+
+	err = validate_master(c);
+	if (err)
+		return err;
+
+	err = dbg_old_index_check_init(c, &c->zroot);
+
+	return err;
+}
+
+/**
+ * ubifs_write_master - write master node.
+ * @c: UBIFS file-system description object
+ *
+ * This function writes the master node. Returns zero in case of success and a
+ * negative error code in case of failure. The master node is written twice to
+ * enable recovery.
+ */
+int ubifs_write_master(struct ubifs_info *c)
+{
+	int err, lnum, offs, len;
+
+	ubifs_assert(c, !c->ro_media && !c->ro_mount);
+	if (c->ro_error)
+		return -EROFS;
+
+	lnum = UBIFS_MST_LNUM;
+	offs = c->mst_offs + c->mst_node_alsz;
+	len = UBIFS_MST_NODE_SZ;
+
+	if (offs + UBIFS_MST_NODE_SZ > c->leb_size) {
+		err = ubifs_leb_unmap(c, lnum);
+		if (err)
+			return err;
+		offs = 0;
+	}
+
+	c->mst_offs = offs;
+	c->mst_node->highest_inum = cpu_to_le64(c->highest_inum);
+
+	ubifs_copy_hash(c, c->zroot.hash, c->mst_node->hash_root_idx);
+	err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs,
+				    offsetof(struct ubifs_mst_node, hmac));
+	if (err)
+		return err;
+
+	lnum += 1;
+
+	if (offs == 0) {
+		err = ubifs_leb_unmap(c, lnum);
+		if (err)
+			return err;
+	}
+	err = ubifs_write_node_hmac(c, c->mst_node, len, lnum, offs,
+				    offsetof(struct ubifs_mst_node, hmac));
+
+	return err;
+}
diff --git a/ubifs-utils/libubifs/misc.h b/ubifs-utils/libubifs/misc.h
new file mode 100644
index 00000000..615878e8
--- /dev/null
+++ b/ubifs-utils/libubifs/misc.h
@@ -0,0 +1,289 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ */
+
+/*
+ * This file contains miscellaneous helper functions.
+ */
+
+#ifndef __UBIFS_MISC_H__
+#define __UBIFS_MISC_H__
+
+/**
+ * ubifs_zn_dirty - check if znode is dirty.
+ * @znode: znode to check
+ *
+ * This helper function returns %1 if @znode is dirty and %0 otherwise.
+ */
+static inline int ubifs_zn_dirty(const struct ubifs_znode *znode)
+{
+	return !!test_bit(DIRTY_ZNODE, &znode->flags);
+}
+
+/**
+ * ubifs_zn_obsolete - check if znode is obsolete.
+ * @znode: znode to check
+ *
+ * This helper function returns %1 if @znode is obsolete and %0 otherwise.
+ */
+static inline int ubifs_zn_obsolete(const struct ubifs_znode *znode)
+{
+	return !!test_bit(OBSOLETE_ZNODE, &znode->flags);
+}
+
+/**
+ * ubifs_zn_cow - check if znode has to be copied on write.
+ * @znode: znode to check
+ *
+ * This helper function returns %1 if @znode is has COW flag set and %0
+ * otherwise.
+ */
+static inline int ubifs_zn_cow(const struct ubifs_znode *znode)
+{
+	return !!test_bit(COW_ZNODE, &znode->flags);
+}
+
+/**
+ * ubifs_wake_up_bgt - wake up background thread.
+ * @c: UBIFS file-system description object
+ */
+static inline void ubifs_wake_up_bgt(struct ubifs_info *c)
+{
+	if (c->bgt && !c->need_bgt) {
+		c->need_bgt = 1;
+		wake_up_process(c->bgt);
+	}
+}
+
+/**
+ * ubifs_tnc_find_child - find next child in znode.
+ * @znode: znode to search at
+ * @start: the zbranch index to start at
+ *
+ * This helper function looks for znode child starting at index @start. Returns
+ * the child or %NULL if no children were found.
+ */
+static inline struct ubifs_znode *
+ubifs_tnc_find_child(struct ubifs_znode *znode, int start)
+{
+	while (start < znode->child_cnt) {
+		if (znode->zbranch[start].znode)
+			return znode->zbranch[start].znode;
+		start += 1;
+	}
+
+	return NULL;
+}
+
+/**
+ * ubifs_inode - get UBIFS inode information by VFS 'struct inode' object.
+ * @inode: the VFS 'struct inode' pointer
+ */
+static inline struct ubifs_inode *ubifs_inode(const struct inode *inode)
+{
+	return container_of(inode, struct ubifs_inode, vfs_inode);
+}
+
+/**
+ * ubifs_compr_present - check if compressor was compiled in.
+ * @compr_type: compressor type to check
+ * @c: the UBIFS file-system description object
+ *
+ * This function returns %1 of compressor of type @compr_type is present, and
+ * %0 if not.
+ */
+static inline int ubifs_compr_present(struct ubifs_info *c, int compr_type)
+{
+	ubifs_assert(c, compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
+	return !!ubifs_compressors[compr_type]->capi_name;
+}
+
+/**
+ * ubifs_compr_name - get compressor name string by its type.
+ * @compr_type: compressor type
+ * @c: the UBIFS file-system description object
+ *
+ * This function returns compressor type string.
+ */
+static inline const char *ubifs_compr_name(struct ubifs_info *c, int compr_type)
+{
+	ubifs_assert(c, compr_type >= 0 && compr_type < UBIFS_COMPR_TYPES_CNT);
+	return ubifs_compressors[compr_type]->name;
+}
+
+/**
+ * ubifs_wbuf_sync - synchronize write-buffer.
+ * @wbuf: write-buffer to synchronize
+ *
+ * This is the same as 'ubifs_wbuf_sync_nolock()' but it does not assume
+ * that the write-buffer is already locked.
+ */
+static inline int ubifs_wbuf_sync(struct ubifs_wbuf *wbuf)
+{
+	int err;
+
+	mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
+	err = ubifs_wbuf_sync_nolock(wbuf);
+	mutex_unlock(&wbuf->io_mutex);
+	return err;
+}
+
+/**
+ * ubifs_encode_dev - encode device node IDs.
+ * @dev: UBIFS device node information
+ * @rdev: device IDs to encode
+ *
+ * This is a helper function which encodes major/minor numbers of a device node
+ * into UBIFS device node description. We use standard Linux "new" and "huge"
+ * encodings.
+ */
+static inline int ubifs_encode_dev(union ubifs_dev_desc *dev, dev_t rdev)
+{
+	dev->new = cpu_to_le32(new_encode_dev(rdev));
+	return sizeof(dev->new);
+}
+
+/**
+ * ubifs_add_dirt - add dirty space to LEB properties.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB to add dirty space for
+ * @dirty: dirty space to add
+ *
+ * This is a helper function which increased amount of dirty LEB space. Returns
+ * zero in case of success and a negative error code in case of failure.
+ */
+static inline int ubifs_add_dirt(struct ubifs_info *c, int lnum, int dirty)
+{
+	return ubifs_update_one_lp(c, lnum, LPROPS_NC, dirty, 0, 0);
+}
+
+/**
+ * ubifs_return_leb - return LEB to lprops.
+ * @c: the UBIFS file-system description object
+ * @lnum: LEB to return
+ *
+ * This helper function cleans the "taken" flag of a logical eraseblock in the
+ * lprops. Returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+static inline int ubifs_return_leb(struct ubifs_info *c, int lnum)
+{
+	return ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
+				   LPROPS_TAKEN, 0);
+}
+
+/**
+ * ubifs_idx_node_sz - return index node size.
+ * @c: the UBIFS file-system description object
+ * @child_cnt: number of children of this index node
+ */
+static inline int ubifs_idx_node_sz(const struct ubifs_info *c, int child_cnt)
+{
+	return UBIFS_IDX_NODE_SZ + (UBIFS_BRANCH_SZ + c->key_len + c->hash_len)
+				   * child_cnt;
+}
+
+/**
+ * ubifs_idx_branch - return pointer to an index branch.
+ * @c: the UBIFS file-system description object
+ * @idx: index node
+ * @bnum: branch number
+ */
+static inline
+struct ubifs_branch *ubifs_idx_branch(const struct ubifs_info *c,
+				      const struct ubifs_idx_node *idx,
+				      int bnum)
+{
+	return (struct ubifs_branch *)((void *)idx->branches +
+			(UBIFS_BRANCH_SZ + c->key_len + c->hash_len) * bnum);
+}
+
+/**
+ * ubifs_idx_key - return pointer to an index key.
+ * @c: the UBIFS file-system description object
+ * @idx: index node
+ */
+static inline void *ubifs_idx_key(const struct ubifs_info *c,
+				  const struct ubifs_idx_node *idx)
+{
+	return (void *)((struct ubifs_branch *)idx->branches)->key;
+}
+
+/**
+ * ubifs_tnc_lookup - look up a file-system node.
+ * @c: UBIFS file-system description object
+ * @key: node key to lookup
+ * @node: the node is returned here
+ *
+ * This function look up and reads node with key @key. The caller has to make
+ * sure the @node buffer is large enough to fit the node. Returns zero in case
+ * of success, %-ENOENT if the node was not found, and a negative error code in
+ * case of failure.
+ */
+static inline int ubifs_tnc_lookup(struct ubifs_info *c,
+				   const union ubifs_key *key, void *node)
+{
+	return ubifs_tnc_locate(c, key, node, NULL, NULL);
+}
+
+/**
+ * ubifs_get_lprops - get reference to LEB properties.
+ * @c: the UBIFS file-system description object
+ *
+ * This function locks lprops. Lprops have to be unlocked by
+ * 'ubifs_release_lprops()'.
+ */
+static inline void ubifs_get_lprops(struct ubifs_info *c)
+{
+	mutex_lock(&c->lp_mutex);
+}
+
+/**
+ * ubifs_release_lprops - release lprops lock.
+ * @c: the UBIFS file-system description object
+ *
+ * This function has to be called after each 'ubifs_get_lprops()' call to
+ * unlock lprops.
+ */
+static inline void ubifs_release_lprops(struct ubifs_info *c)
+{
+	ubifs_assert(c, mutex_is_locked(&c->lp_mutex));
+	ubifs_assert(c, c->lst.empty_lebs >= 0 &&
+		     c->lst.empty_lebs <= c->main_lebs);
+	mutex_unlock(&c->lp_mutex);
+}
+
+/**
+ * ubifs_next_log_lnum - switch to the next log LEB.
+ * @c: UBIFS file-system description object
+ * @lnum: current log LEB
+ *
+ * This helper function returns the log LEB number which goes next after LEB
+ * 'lnum'.
+ */
+static inline int ubifs_next_log_lnum(const struct ubifs_info *c, int lnum)
+{
+	lnum += 1;
+	if (lnum > c->log_last)
+		lnum = UBIFS_LOG_LNUM;
+
+	return lnum;
+}
+
+static inline int ubifs_xattr_max_cnt(struct ubifs_info *c)
+{
+	int max_xattrs = (c->leb_size / 2) / UBIFS_INO_NODE_SZ;
+
+	ubifs_assert(c, max_xattrs < c->max_orphans);
+	return max_xattrs;
+}
+
+const char *ubifs_assert_action_name(struct ubifs_info *c);
+
+#endif /* __UBIFS_MISC_H__ */
diff --git a/ubifs-utils/libubifs/orphan.c b/ubifs-utils/libubifs/orphan.c
new file mode 100644
index 00000000..fb957d96
--- /dev/null
+++ b/ubifs-utils/libubifs/orphan.c
@@ -0,0 +1,947 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Author: Adrian Hunter
+ */
+
+#include "ubifs.h"
+
+/*
+ * An orphan is an inode number whose inode node has been committed to the index
+ * with a link count of zero. That happens when an open file is deleted
+ * (unlinked) and then a commit is run. In the normal course of events the inode
+ * would be deleted when the file is closed. However in the case of an unclean
+ * unmount, orphans need to be accounted for. After an unclean unmount, the
+ * orphans' inodes must be deleted which means either scanning the entire index
+ * looking for them, or keeping a list on flash somewhere. This unit implements
+ * the latter approach.
+ *
+ * The orphan area is a fixed number of LEBs situated between the LPT area and
+ * the main area. The number of orphan area LEBs is specified when the file
+ * system is created. The minimum number is 1. The size of the orphan area
+ * should be so that it can hold the maximum number of orphans that are expected
+ * to ever exist at one time.
+ *
+ * The number of orphans that can fit in a LEB is:
+ *
+ *         (c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64)
+ *
+ * For example: a 15872 byte LEB can fit 1980 orphans so 1 LEB may be enough.
+ *
+ * Orphans are accumulated in a rb-tree. When an inode's link count drops to
+ * zero, the inode number is added to the rb-tree. It is removed from the tree
+ * when the inode is deleted.  Any new orphans that are in the orphan tree when
+ * the commit is run, are written to the orphan area in 1 or more orphan nodes.
+ * If the orphan area is full, it is consolidated to make space.  There is
+ * always enough space because validation prevents the user from creating more
+ * than the maximum number of orphans allowed.
+ */
+
+static int dbg_check_orphans(struct ubifs_info *c);
+
+/**
+ * ubifs_add_orphan - add an orphan.
+ * @c: UBIFS file-system description object
+ * @inum: orphan inode number
+ *
+ * Add an orphan. This function is called when an inodes link count drops to
+ * zero.
+ */
+int ubifs_add_orphan(struct ubifs_info *c, ino_t inum)
+{
+	struct ubifs_orphan *orphan, *o;
+	struct rb_node **p, *parent = NULL;
+
+	orphan = kzalloc(sizeof(struct ubifs_orphan), GFP_NOFS);
+	if (!orphan)
+		return -ENOMEM;
+	orphan->inum = inum;
+	orphan->new = 1;
+
+	spin_lock(&c->orphan_lock);
+	if (c->tot_orphans >= c->max_orphans) {
+		spin_unlock(&c->orphan_lock);
+		kfree(orphan);
+		return -ENFILE;
+	}
+	p = &c->orph_tree.rb_node;
+	while (*p) {
+		parent = *p;
+		o = rb_entry(parent, struct ubifs_orphan, rb);
+		if (inum < o->inum)
+			p = &(*p)->rb_left;
+		else if (inum > o->inum)
+			p = &(*p)->rb_right;
+		else {
+			ubifs_err(c, "orphaned twice");
+			spin_unlock(&c->orphan_lock);
+			kfree(orphan);
+			return -EINVAL;
+		}
+	}
+	c->tot_orphans += 1;
+	c->new_orphans += 1;
+	rb_link_node(&orphan->rb, parent, p);
+	rb_insert_color(&orphan->rb, &c->orph_tree);
+	list_add_tail(&orphan->list, &c->orph_list);
+	list_add_tail(&orphan->new_list, &c->orph_new);
+
+	spin_unlock(&c->orphan_lock);
+	dbg_gen("ino %lu", (unsigned long)inum);
+	return 0;
+}
+
+static struct ubifs_orphan *lookup_orphan(struct ubifs_info *c, ino_t inum)
+{
+	struct ubifs_orphan *o;
+	struct rb_node *p;
+
+	p = c->orph_tree.rb_node;
+	while (p) {
+		o = rb_entry(p, struct ubifs_orphan, rb);
+		if (inum < o->inum)
+			p = p->rb_left;
+		else if (inum > o->inum)
+			p = p->rb_right;
+		else {
+			return o;
+		}
+	}
+	return NULL;
+}
+
+static void __orphan_drop(struct ubifs_info *c, struct ubifs_orphan *o)
+{
+	rb_erase(&o->rb, &c->orph_tree);
+	list_del(&o->list);
+	c->tot_orphans -= 1;
+
+	if (o->new) {
+		list_del(&o->new_list);
+		c->new_orphans -= 1;
+	}
+
+	kfree(o);
+}
+
+static void orphan_delete(struct ubifs_info *c, struct ubifs_orphan *orph)
+{
+	if (orph->del) {
+		dbg_gen("deleted twice ino %lu", (unsigned long)orph->inum);
+		return;
+	}
+
+	if (orph->cmt) {
+		orph->del = 1;
+		rb_erase(&orph->rb, &c->orph_tree);
+		orph->dnext = c->orph_dnext;
+		c->orph_dnext = orph;
+		dbg_gen("delete later ino %lu", (unsigned long)orph->inum);
+		return;
+	}
+
+	__orphan_drop(c, orph);
+}
+
+/**
+ * ubifs_delete_orphan - delete an orphan.
+ * @c: UBIFS file-system description object
+ * @inum: orphan inode number
+ *
+ * Delete an orphan. This function is called when an inode is deleted.
+ */
+void ubifs_delete_orphan(struct ubifs_info *c, ino_t inum)
+{
+	struct ubifs_orphan *orph;
+
+	spin_lock(&c->orphan_lock);
+
+	orph = lookup_orphan(c, inum);
+	if (!orph) {
+		spin_unlock(&c->orphan_lock);
+		ubifs_err(c, "missing orphan ino %lu", (unsigned long)inum);
+		dump_stack();
+
+		return;
+	}
+
+	orphan_delete(c, orph);
+
+	spin_unlock(&c->orphan_lock);
+}
+
+/**
+ * ubifs_orphan_start_commit - start commit of orphans.
+ * @c: UBIFS file-system description object
+ *
+ * Start commit of orphans.
+ */
+int ubifs_orphan_start_commit(struct ubifs_info *c)
+{
+	struct ubifs_orphan *orphan, **last;
+
+	spin_lock(&c->orphan_lock);
+	last = &c->orph_cnext;
+	list_for_each_entry(orphan, &c->orph_new, new_list) {
+		ubifs_assert(c, orphan->new);
+		ubifs_assert(c, !orphan->cmt);
+		orphan->new = 0;
+		orphan->cmt = 1;
+		*last = orphan;
+		last = &orphan->cnext;
+	}
+	*last = NULL;
+	c->cmt_orphans = c->new_orphans;
+	c->new_orphans = 0;
+	dbg_cmt("%d orphans to commit", c->cmt_orphans);
+	INIT_LIST_HEAD(&c->orph_new);
+	if (c->tot_orphans == 0)
+		c->no_orphs = 1;
+	else
+		c->no_orphs = 0;
+	spin_unlock(&c->orphan_lock);
+	return 0;
+}
+
+/**
+ * avail_orphs - calculate available space.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns the number of orphans that can be written in the
+ * available space.
+ */
+static int avail_orphs(struct ubifs_info *c)
+{
+	int avail_lebs, avail, gap;
+
+	avail_lebs = c->orph_lebs - (c->ohead_lnum - c->orph_first) - 1;
+	avail = avail_lebs *
+	       ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
+	gap = c->leb_size - c->ohead_offs;
+	if (gap >= UBIFS_ORPH_NODE_SZ + sizeof(__le64))
+		avail += (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
+	return avail;
+}
+
+/**
+ * tot_avail_orphs - calculate total space.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns the number of orphans that can be written in half
+ * the total space. That leaves half the space for adding new orphans.
+ */
+static int tot_avail_orphs(struct ubifs_info *c)
+{
+	int avail_lebs, avail;
+
+	avail_lebs = c->orph_lebs;
+	avail = avail_lebs *
+	       ((c->leb_size - UBIFS_ORPH_NODE_SZ) / sizeof(__le64));
+	return avail / 2;
+}
+
+/**
+ * do_write_orph_node - write a node to the orphan head.
+ * @c: UBIFS file-system description object
+ * @len: length of node
+ * @atomic: write atomically
+ *
+ * This function writes a node to the orphan head from the orphan buffer. If
+ * %atomic is not zero, then the write is done atomically. On success, %0 is
+ * returned, otherwise a negative error code is returned.
+ */
+static int do_write_orph_node(struct ubifs_info *c, int len, int atomic)
+{
+	int err = 0;
+
+	if (atomic) {
+		ubifs_assert(c, c->ohead_offs == 0);
+		ubifs_prepare_node(c, c->orph_buf, len, 1);
+		len = ALIGN(len, c->min_io_size);
+		err = ubifs_leb_change(c, c->ohead_lnum, c->orph_buf, len);
+	} else {
+		if (c->ohead_offs == 0) {
+			/* Ensure LEB has been unmapped */
+			err = ubifs_leb_unmap(c, c->ohead_lnum);
+			if (err)
+				return err;
+		}
+		err = ubifs_write_node(c, c->orph_buf, len, c->ohead_lnum,
+				       c->ohead_offs);
+	}
+	return err;
+}
+
+/**
+ * write_orph_node - write an orphan node.
+ * @c: UBIFS file-system description object
+ * @atomic: write atomically
+ *
+ * This function builds an orphan node from the cnext list and writes it to the
+ * orphan head. On success, %0 is returned, otherwise a negative error code
+ * is returned.
+ */
+static int write_orph_node(struct ubifs_info *c, int atomic)
+{
+	struct ubifs_orphan *orphan, *cnext;
+	struct ubifs_orph_node *orph;
+	int gap, err, len, cnt, i;
+
+	ubifs_assert(c, c->cmt_orphans > 0);
+	gap = c->leb_size - c->ohead_offs;
+	if (gap < UBIFS_ORPH_NODE_SZ + sizeof(__le64)) {
+		c->ohead_lnum += 1;
+		c->ohead_offs = 0;
+		gap = c->leb_size;
+		if (c->ohead_lnum > c->orph_last) {
+			/*
+			 * We limit the number of orphans so that this should
+			 * never happen.
+			 */
+			ubifs_err(c, "out of space in orphan area");
+			return -EINVAL;
+		}
+	}
+	cnt = (gap - UBIFS_ORPH_NODE_SZ) / sizeof(__le64);
+	if (cnt > c->cmt_orphans)
+		cnt = c->cmt_orphans;
+	len = UBIFS_ORPH_NODE_SZ + cnt * sizeof(__le64);
+	ubifs_assert(c, c->orph_buf);
+	orph = c->orph_buf;
+	orph->ch.node_type = UBIFS_ORPH_NODE;
+	spin_lock(&c->orphan_lock);
+	cnext = c->orph_cnext;
+	for (i = 0; i < cnt; i++) {
+		orphan = cnext;
+		ubifs_assert(c, orphan->cmt);
+		orph->inos[i] = cpu_to_le64(orphan->inum);
+		orphan->cmt = 0;
+		cnext = orphan->cnext;
+		orphan->cnext = NULL;
+	}
+	c->orph_cnext = cnext;
+	c->cmt_orphans -= cnt;
+	spin_unlock(&c->orphan_lock);
+	if (c->cmt_orphans)
+		orph->cmt_no = cpu_to_le64(c->cmt_no);
+	else
+		/* Mark the last node of the commit */
+		orph->cmt_no = cpu_to_le64((c->cmt_no) | (1ULL << 63));
+	ubifs_assert(c, c->ohead_offs + len <= c->leb_size);
+	ubifs_assert(c, c->ohead_lnum >= c->orph_first);
+	ubifs_assert(c, c->ohead_lnum <= c->orph_last);
+	err = do_write_orph_node(c, len, atomic);
+	c->ohead_offs += ALIGN(len, c->min_io_size);
+	c->ohead_offs = ALIGN(c->ohead_offs, 8);
+	return err;
+}
+
+/**
+ * write_orph_nodes - write orphan nodes until there are no more to commit.
+ * @c: UBIFS file-system description object
+ * @atomic: write atomically
+ *
+ * This function writes orphan nodes for all the orphans to commit. On success,
+ * %0 is returned, otherwise a negative error code is returned.
+ */
+static int write_orph_nodes(struct ubifs_info *c, int atomic)
+{
+	int err;
+
+	while (c->cmt_orphans > 0) {
+		err = write_orph_node(c, atomic);
+		if (err)
+			return err;
+	}
+	if (atomic) {
+		int lnum;
+
+		/* Unmap any unused LEBs after consolidation */
+		for (lnum = c->ohead_lnum + 1; lnum <= c->orph_last; lnum++) {
+			err = ubifs_leb_unmap(c, lnum);
+			if (err)
+				return err;
+		}
+	}
+	return 0;
+}
+
+/**
+ * consolidate - consolidate the orphan area.
+ * @c: UBIFS file-system description object
+ *
+ * This function enables consolidation by putting all the orphans into the list
+ * to commit. The list is in the order that the orphans were added, and the
+ * LEBs are written atomically in order, so at no time can orphans be lost by
+ * an unclean unmount.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int consolidate(struct ubifs_info *c)
+{
+	int tot_avail = tot_avail_orphs(c), err = 0;
+
+	spin_lock(&c->orphan_lock);
+	dbg_cmt("there is space for %d orphans and there are %d",
+		tot_avail, c->tot_orphans);
+	if (c->tot_orphans - c->new_orphans <= tot_avail) {
+		struct ubifs_orphan *orphan, **last;
+		int cnt = 0;
+
+		/* Change the cnext list to include all non-new orphans */
+		last = &c->orph_cnext;
+		list_for_each_entry(orphan, &c->orph_list, list) {
+			if (orphan->new)
+				continue;
+			orphan->cmt = 1;
+			*last = orphan;
+			last = &orphan->cnext;
+			cnt += 1;
+		}
+		*last = NULL;
+		ubifs_assert(c, cnt == c->tot_orphans - c->new_orphans);
+		c->cmt_orphans = cnt;
+		c->ohead_lnum = c->orph_first;
+		c->ohead_offs = 0;
+	} else {
+		/*
+		 * We limit the number of orphans so that this should
+		 * never happen.
+		 */
+		ubifs_err(c, "out of space in orphan area");
+		err = -EINVAL;
+	}
+	spin_unlock(&c->orphan_lock);
+	return err;
+}
+
+/**
+ * commit_orphans - commit orphans.
+ * @c: UBIFS file-system description object
+ *
+ * This function commits orphans to flash. On success, %0 is returned,
+ * otherwise a negative error code is returned.
+ */
+static int commit_orphans(struct ubifs_info *c)
+{
+	int avail, atomic = 0, err;
+
+	ubifs_assert(c, c->cmt_orphans > 0);
+	avail = avail_orphs(c);
+	if (avail < c->cmt_orphans) {
+		/* Not enough space to write new orphans, so consolidate */
+		err = consolidate(c);
+		if (err)
+			return err;
+		atomic = 1;
+	}
+	err = write_orph_nodes(c, atomic);
+	return err;
+}
+
+/**
+ * erase_deleted - erase the orphans marked for deletion.
+ * @c: UBIFS file-system description object
+ *
+ * During commit, the orphans being committed cannot be deleted, so they are
+ * marked for deletion and deleted by this function. Also, the recovery
+ * adds killed orphans to the deletion list, and therefore they are deleted
+ * here too.
+ */
+static void erase_deleted(struct ubifs_info *c)
+{
+	struct ubifs_orphan *orphan, *dnext;
+
+	spin_lock(&c->orphan_lock);
+	dnext = c->orph_dnext;
+	while (dnext) {
+		orphan = dnext;
+		dnext = orphan->dnext;
+		ubifs_assert(c, !orphan->new);
+		ubifs_assert(c, orphan->del);
+		list_del(&orphan->list);
+		c->tot_orphans -= 1;
+		dbg_gen("deleting orphan ino %lu", (unsigned long)orphan->inum);
+		kfree(orphan);
+	}
+	c->orph_dnext = NULL;
+	spin_unlock(&c->orphan_lock);
+}
+
+/**
+ * ubifs_orphan_end_commit - end commit of orphans.
+ * @c: UBIFS file-system description object
+ *
+ * End commit of orphans.
+ */
+int ubifs_orphan_end_commit(struct ubifs_info *c)
+{
+	int err;
+
+	if (c->cmt_orphans != 0) {
+		err = commit_orphans(c);
+		if (err)
+			return err;
+	}
+	erase_deleted(c);
+	err = dbg_check_orphans(c);
+	return err;
+}
+
+/**
+ * ubifs_clear_orphans - erase all LEBs used for orphans.
+ * @c: UBIFS file-system description object
+ *
+ * If recovery is not required, then the orphans from the previous session
+ * are not needed. This function locates the LEBs used to record
+ * orphans, and un-maps them.
+ */
+int ubifs_clear_orphans(struct ubifs_info *c)
+{
+	int lnum, err;
+
+	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
+		err = ubifs_leb_unmap(c, lnum);
+		if (err)
+			return err;
+	}
+	c->ohead_lnum = c->orph_first;
+	c->ohead_offs = 0;
+	return 0;
+}
+
+/**
+ * do_kill_orphans - remove orphan inodes from the index.
+ * @c: UBIFS file-system description object
+ * @sleb: scanned LEB
+ * @last_cmt_no: cmt_no of last orphan node read is passed and returned here
+ * @outofdate: whether the LEB is out of date is returned here
+ * @last_flagged: whether the end orphan node is encountered
+ *
+ * This function is a helper to the 'kill_orphans()' function. It goes through
+ * every orphan node in a LEB and for every inode number recorded, removes
+ * all keys for that inode from the TNC.
+ */
+static int do_kill_orphans(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
+			   unsigned long long *last_cmt_no, int *outofdate,
+			   int *last_flagged)
+{
+	struct ubifs_scan_node *snod;
+	struct ubifs_orph_node *orph;
+	struct ubifs_ino_node *ino = NULL;
+	unsigned long long cmt_no;
+	ino_t inum;
+	int i, n, err, first = 1;
+
+	ino = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
+	if (!ino)
+		return -ENOMEM;
+
+	list_for_each_entry(snod, &sleb->nodes, list) {
+		if (snod->type != UBIFS_ORPH_NODE) {
+			ubifs_err(c, "invalid node type %d in orphan area at %d:%d",
+				  snod->type, sleb->lnum, snod->offs);
+			ubifs_dump_node(c, snod->node,
+					c->leb_size - snod->offs);
+			err = -EINVAL;
+			goto out_free;
+		}
+
+		orph = snod->node;
+
+		/* Check commit number */
+		cmt_no = le64_to_cpu(orph->cmt_no) & LLONG_MAX;
+		/*
+		 * The commit number on the master node may be less, because
+		 * of a failed commit. If there are several failed commits in a
+		 * row, the commit number written on orphan nodes will continue
+		 * to increase (because the commit number is adjusted here) even
+		 * though the commit number on the master node stays the same
+		 * because the master node has not been re-written.
+		 */
+		if (cmt_no > c->cmt_no)
+			c->cmt_no = cmt_no;
+		if (cmt_no < *last_cmt_no && *last_flagged) {
+			/*
+			 * The last orphan node had a higher commit number and
+			 * was flagged as the last written for that commit
+			 * number. That makes this orphan node, out of date.
+			 */
+			if (!first) {
+				ubifs_err(c, "out of order commit number %llu in orphan node at %d:%d",
+					  cmt_no, sleb->lnum, snod->offs);
+				ubifs_dump_node(c, snod->node,
+						c->leb_size - snod->offs);
+				err = -EINVAL;
+				goto out_free;
+			}
+			dbg_rcvry("out of date LEB %d", sleb->lnum);
+			*outofdate = 1;
+			err = 0;
+			goto out_free;
+		}
+
+		if (first)
+			first = 0;
+
+		n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
+		for (i = 0; i < n; i++) {
+			union ubifs_key key;
+
+			inum = le64_to_cpu(orph->inos[i]);
+
+			ino_key_init(c, &key, inum);
+			err = ubifs_tnc_lookup(c, &key, ino);
+			if (err && err != -ENOENT)
+				goto out_free;
+
+			/*
+			 * Check whether an inode can really get deleted.
+			 * linkat() with O_TMPFILE allows rebirth of an inode.
+			 */
+			if (err == 0 && ino->nlink == 0) {
+				dbg_rcvry("deleting orphaned inode %lu",
+					  (unsigned long)inum);
+
+				err = ubifs_tnc_remove_ino(c, inum);
+				if (err)
+					goto out_ro;
+			}
+		}
+
+		*last_cmt_no = cmt_no;
+		if (le64_to_cpu(orph->cmt_no) & (1ULL << 63)) {
+			dbg_rcvry("last orph node for commit %llu at %d:%d",
+				  cmt_no, sleb->lnum, snod->offs);
+			*last_flagged = 1;
+		} else
+			*last_flagged = 0;
+	}
+
+	err = 0;
+out_free:
+	kfree(ino);
+	return err;
+
+out_ro:
+	ubifs_ro_mode(c, err);
+	kfree(ino);
+	return err;
+}
+
+/**
+ * kill_orphans - remove all orphan inodes from the index.
+ * @c: UBIFS file-system description object
+ *
+ * If recovery is required, then orphan inodes recorded during the previous
+ * session (which ended with an unclean unmount) must be deleted from the index.
+ * This is done by updating the TNC, but since the index is not updated until
+ * the next commit, the LEBs where the orphan information is recorded are not
+ * erased until the next commit.
+ */
+static int kill_orphans(struct ubifs_info *c)
+{
+	unsigned long long last_cmt_no = 0;
+	int lnum, err = 0, outofdate = 0, last_flagged = 0;
+
+	c->ohead_lnum = c->orph_first;
+	c->ohead_offs = 0;
+	/* Check no-orphans flag and skip this if no orphans */
+	if (c->no_orphs) {
+		dbg_rcvry("no orphans");
+		return 0;
+	}
+	/*
+	 * Orph nodes always start at c->orph_first and are written to each
+	 * successive LEB in turn. Generally unused LEBs will have been unmapped
+	 * but may contain out of date orphan nodes if the unmap didn't go
+	 * through. In addition, the last orphan node written for each commit is
+	 * marked (top bit of orph->cmt_no is set to 1). It is possible that
+	 * there are orphan nodes from the next commit (i.e. the commit did not
+	 * complete successfully). In that case, no orphans will have been lost
+	 * due to the way that orphans are written, and any orphans added will
+	 * be valid orphans anyway and so can be deleted.
+	 */
+	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
+		struct ubifs_scan_leb *sleb;
+
+		dbg_rcvry("LEB %d", lnum);
+		sleb = ubifs_scan(c, lnum, 0, c->sbuf, 1);
+		if (IS_ERR(sleb)) {
+			if (PTR_ERR(sleb) == -EUCLEAN)
+				sleb = ubifs_recover_leb(c, lnum, 0,
+							 c->sbuf, -1);
+			if (IS_ERR(sleb)) {
+				err = PTR_ERR(sleb);
+				break;
+			}
+		}
+		err = do_kill_orphans(c, sleb, &last_cmt_no, &outofdate,
+				      &last_flagged);
+		if (err || outofdate) {
+			ubifs_scan_destroy(sleb);
+			break;
+		}
+		if (sleb->endpt) {
+			c->ohead_lnum = lnum;
+			c->ohead_offs = sleb->endpt;
+		}
+		ubifs_scan_destroy(sleb);
+	}
+	return err;
+}
+
+/**
+ * ubifs_mount_orphans - delete orphan inodes and erase LEBs that recorded them.
+ * @c: UBIFS file-system description object
+ * @unclean: indicates recovery from unclean unmount
+ * @read_only: indicates read only mount
+ *
+ * This function is called when mounting to erase orphans from the previous
+ * session. If UBIFS was not unmounted cleanly, then the inodes recorded as
+ * orphans are deleted.
+ */
+int ubifs_mount_orphans(struct ubifs_info *c, int unclean, int read_only)
+{
+	int err = 0;
+
+	c->max_orphans = tot_avail_orphs(c);
+
+	if (!read_only) {
+		c->orph_buf = vmalloc(c->leb_size);
+		if (!c->orph_buf)
+			return -ENOMEM;
+	}
+
+	if (unclean)
+		err = kill_orphans(c);
+	else if (!read_only)
+		err = ubifs_clear_orphans(c);
+
+	return err;
+}
+
+/*
+ * Everything below is related to debugging.
+ */
+
+struct check_orphan {
+	struct rb_node rb;
+	ino_t inum;
+};
+
+struct check_info {
+	unsigned long last_ino;
+	unsigned long tot_inos;
+	unsigned long missing;
+	unsigned long long leaf_cnt;
+	struct ubifs_ino_node *node;
+	struct rb_root root;
+};
+
+static bool dbg_find_orphan(struct ubifs_info *c, ino_t inum)
+{
+	bool found = false;
+
+	spin_lock(&c->orphan_lock);
+	found = !!lookup_orphan(c, inum);
+	spin_unlock(&c->orphan_lock);
+
+	return found;
+}
+
+static int dbg_ins_check_orphan(struct rb_root *root, ino_t inum)
+{
+	struct check_orphan *orphan, *o;
+	struct rb_node **p, *parent = NULL;
+
+	orphan = kzalloc(sizeof(struct check_orphan), GFP_NOFS);
+	if (!orphan)
+		return -ENOMEM;
+	orphan->inum = inum;
+
+	p = &root->rb_node;
+	while (*p) {
+		parent = *p;
+		o = rb_entry(parent, struct check_orphan, rb);
+		if (inum < o->inum)
+			p = &(*p)->rb_left;
+		else if (inum > o->inum)
+			p = &(*p)->rb_right;
+		else {
+			kfree(orphan);
+			return 0;
+		}
+	}
+	rb_link_node(&orphan->rb, parent, p);
+	rb_insert_color(&orphan->rb, root);
+	return 0;
+}
+
+static int dbg_find_check_orphan(struct rb_root *root, ino_t inum)
+{
+	struct check_orphan *o;
+	struct rb_node *p;
+
+	p = root->rb_node;
+	while (p) {
+		o = rb_entry(p, struct check_orphan, rb);
+		if (inum < o->inum)
+			p = p->rb_left;
+		else if (inum > o->inum)
+			p = p->rb_right;
+		else
+			return 1;
+	}
+	return 0;
+}
+
+static void dbg_free_check_tree(struct rb_root *root)
+{
+	struct check_orphan *o, *n;
+
+	rbtree_postorder_for_each_entry_safe(o, n, root, rb)
+		kfree(o);
+}
+
+static int dbg_orphan_check(struct ubifs_info *c, struct ubifs_zbranch *zbr,
+			    void *priv)
+{
+	struct check_info *ci = priv;
+	ino_t inum;
+	int err;
+
+	inum = key_inum(c, &zbr->key);
+	if (inum != ci->last_ino) {
+		/*
+		 * Lowest node type is the inode node or xattr entry(when
+		 * selinux/encryption is enabled), so it comes first
+		 */
+		if (key_type(c, &zbr->key) != UBIFS_INO_KEY &&
+		    key_type(c, &zbr->key) != UBIFS_XENT_KEY)
+			ubifs_err(c, "found orphan node ino %lu, type %d",
+				  (unsigned long)inum, key_type(c, &zbr->key));
+		ci->last_ino = inum;
+		ci->tot_inos += 1;
+		err = ubifs_tnc_read_node(c, zbr, ci->node);
+		if (err) {
+			ubifs_err(c, "node read failed, error %d", err);
+			return err;
+		}
+		if (ci->node->nlink == 0)
+			/* Must be recorded as an orphan */
+			if (!dbg_find_check_orphan(&ci->root, inum) &&
+			    !dbg_find_orphan(c, inum)) {
+				ubifs_err(c, "missing orphan, ino %lu",
+					  (unsigned long)inum);
+				ci->missing += 1;
+			}
+	}
+	ci->leaf_cnt += 1;
+	return 0;
+}
+
+static int dbg_read_orphans(struct check_info *ci, struct ubifs_scan_leb *sleb)
+{
+	struct ubifs_scan_node *snod;
+	struct ubifs_orph_node *orph;
+	ino_t inum;
+	int i, n, err;
+
+	list_for_each_entry(snod, &sleb->nodes, list) {
+		cond_resched();
+		if (snod->type != UBIFS_ORPH_NODE)
+			continue;
+		orph = snod->node;
+		n = (le32_to_cpu(orph->ch.len) - UBIFS_ORPH_NODE_SZ) >> 3;
+		for (i = 0; i < n; i++) {
+			inum = le64_to_cpu(orph->inos[i]);
+			err = dbg_ins_check_orphan(&ci->root, inum);
+			if (err)
+				return err;
+		}
+	}
+	return 0;
+}
+
+static int dbg_scan_orphans(struct ubifs_info *c, struct check_info *ci)
+{
+	int lnum, err = 0;
+	void *buf;
+
+	/* Check no-orphans flag and skip this if no orphans */
+	if (c->no_orphs)
+		return 0;
+
+	buf = __vmalloc(c->leb_size, GFP_NOFS);
+	if (!buf) {
+		ubifs_err(c, "cannot allocate memory to check orphans");
+		return 0;
+	}
+
+	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
+		struct ubifs_scan_leb *sleb;
+
+		sleb = ubifs_scan(c, lnum, 0, buf, 0);
+		if (IS_ERR(sleb)) {
+			err = PTR_ERR(sleb);
+			break;
+		}
+
+		err = dbg_read_orphans(ci, sleb);
+		ubifs_scan_destroy(sleb);
+		if (err)
+			break;
+	}
+
+	vfree(buf);
+	return err;
+}
+
+static int dbg_check_orphans(struct ubifs_info *c)
+{
+	struct check_info ci;
+	int err;
+
+	if (!dbg_is_chk_orph(c))
+		return 0;
+
+	ci.last_ino = 0;
+	ci.tot_inos = 0;
+	ci.missing  = 0;
+	ci.leaf_cnt = 0;
+	ci.root = RB_ROOT;
+	ci.node = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
+	if (!ci.node) {
+		ubifs_err(c, "out of memory");
+		return -ENOMEM;
+	}
+
+	err = dbg_scan_orphans(c, &ci);
+	if (err)
+		goto out;
+
+	err = dbg_walk_index(c, &dbg_orphan_check, NULL, &ci);
+	if (err) {
+		ubifs_err(c, "cannot scan TNC, error %d", err);
+		goto out;
+	}
+
+	if (ci.missing) {
+		ubifs_err(c, "%lu missing orphan(s)", ci.missing);
+		err = -EINVAL;
+		goto out;
+	}
+
+	dbg_cmt("last inode number is %lu", ci.last_ino);
+	dbg_cmt("total number of inodes is %lu", ci.tot_inos);
+	dbg_cmt("total number of leaf nodes is %llu", ci.leaf_cnt);
+
+out:
+	dbg_free_check_tree(&ci.root);
+	kfree(ci.node);
+	return err;
+}
diff --git a/ubifs-utils/libubifs/recovery.c b/ubifs-utils/libubifs/recovery.c
new file mode 100644
index 00000000..f0d51dd2
--- /dev/null
+++ b/ubifs-utils/libubifs/recovery.c
@@ -0,0 +1,1588 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file implements functions needed to recover from unclean un-mounts.
+ * When UBIFS is mounted, it checks a flag on the master node to determine if
+ * an un-mount was completed successfully. If not, the process of mounting
+ * incorporates additional checking and fixing of on-flash data structures.
+ * UBIFS always cleans away all remnants of an unclean un-mount, so that
+ * errors do not accumulate. However UBIFS defers recovery if it is mounted
+ * read-only, and the flash is not modified in that case.
+ *
+ * The general UBIFS approach to the recovery is that it recovers from
+ * corruptions which could be caused by power cuts, but it refuses to recover
+ * from corruption caused by other reasons. And UBIFS tries to distinguish
+ * between these 2 reasons of corruptions and silently recover in the former
+ * case and loudly complain in the latter case.
+ *
+ * UBIFS writes only to erased LEBs, so it writes only to the flash space
+ * containing only 0xFFs. UBIFS also always writes strictly from the beginning
+ * of the LEB to the end. And UBIFS assumes that the underlying flash media
+ * writes in @c->max_write_size bytes at a time.
+ *
+ * Hence, if UBIFS finds a corrupted node at offset X, it expects only the min.
+ * I/O unit corresponding to offset X to contain corrupted data, all the
+ * following min. I/O units have to contain empty space (all 0xFFs). If this is
+ * not true, the corruption cannot be the result of a power cut, and UBIFS
+ * refuses to mount.
+ */
+
+#include <linux/crc32.h>
+#include <linux/slab.h>
+#include "ubifs.h"
+
+/**
+ * is_empty - determine whether a buffer is empty (contains all 0xff).
+ * @buf: buffer to clean
+ * @len: length of buffer
+ *
+ * This function returns %1 if the buffer is empty (contains all 0xff) otherwise
+ * %0 is returned.
+ */
+static int is_empty(void *buf, int len)
+{
+	uint8_t *p = buf;
+	int i;
+
+	for (i = 0; i < len; i++)
+		if (*p++ != 0xff)
+			return 0;
+	return 1;
+}
+
+/**
+ * first_non_ff - find offset of the first non-0xff byte.
+ * @buf: buffer to search in
+ * @len: length of buffer
+ *
+ * This function returns offset of the first non-0xff byte in @buf or %-1 if
+ * the buffer contains only 0xff bytes.
+ */
+static int first_non_ff(void *buf, int len)
+{
+	uint8_t *p = buf;
+	int i;
+
+	for (i = 0; i < len; i++)
+		if (*p++ != 0xff)
+			return i;
+	return -1;
+}
+
+/**
+ * get_master_node - get the last valid master node allowing for corruption.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number
+ * @pbuf: buffer containing the LEB read, is returned here
+ * @mst: master node, if found, is returned here
+ * @cor: corruption, if found, is returned here
+ *
+ * This function allocates a buffer, reads the LEB into it, and finds and
+ * returns the last valid master node allowing for one area of corruption.
+ * The corrupt area, if there is one, must be consistent with the assumption
+ * that it is the result of an unclean unmount while the master node was being
+ * written. Under those circumstances, it is valid to use the previously written
+ * master node.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int get_master_node(const struct ubifs_info *c, int lnum, void **pbuf,
+			   struct ubifs_mst_node **mst, void **cor)
+{
+	const int sz = c->mst_node_alsz;
+	int err, offs, len;
+	void *sbuf, *buf;
+
+	sbuf = vmalloc(c->leb_size);
+	if (!sbuf)
+		return -ENOMEM;
+
+	err = ubifs_leb_read(c, lnum, sbuf, 0, c->leb_size, 0);
+	if (err && err != -EBADMSG)
+		goto out_free;
+
+	/* Find the first position that is definitely not a node */
+	offs = 0;
+	buf = sbuf;
+	len = c->leb_size;
+	while (offs + UBIFS_MST_NODE_SZ <= c->leb_size) {
+		struct ubifs_ch *ch = buf;
+
+		if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC)
+			break;
+		offs += sz;
+		buf  += sz;
+		len  -= sz;
+	}
+	/* See if there was a valid master node before that */
+	if (offs) {
+		int ret;
+
+		offs -= sz;
+		buf  -= sz;
+		len  += sz;
+		ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1);
+		if (ret != SCANNED_A_NODE && offs) {
+			/* Could have been corruption so check one place back */
+			offs -= sz;
+			buf  -= sz;
+			len  += sz;
+			ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1);
+			if (ret != SCANNED_A_NODE)
+				/*
+				 * We accept only one area of corruption because
+				 * we are assuming that it was caused while
+				 * trying to write a master node.
+				 */
+				goto out_err;
+		}
+		if (ret == SCANNED_A_NODE) {
+			struct ubifs_ch *ch = buf;
+
+			if (ch->node_type != UBIFS_MST_NODE)
+				goto out_err;
+			dbg_rcvry("found a master node at %d:%d", lnum, offs);
+			*mst = buf;
+			offs += sz;
+			buf  += sz;
+			len  -= sz;
+		}
+	}
+	/* Check for corruption */
+	if (offs < c->leb_size) {
+		if (!is_empty(buf, min_t(int, len, sz))) {
+			*cor = buf;
+			dbg_rcvry("found corruption at %d:%d", lnum, offs);
+		}
+		offs += sz;
+		buf  += sz;
+		len  -= sz;
+	}
+	/* Check remaining empty space */
+	if (offs < c->leb_size)
+		if (!is_empty(buf, len))
+			goto out_err;
+	*pbuf = sbuf;
+	return 0;
+
+out_err:
+	err = -EINVAL;
+out_free:
+	vfree(sbuf);
+	*mst = NULL;
+	*cor = NULL;
+	return err;
+}
+
+/**
+ * write_rcvrd_mst_node - write recovered master node.
+ * @c: UBIFS file-system description object
+ * @mst: master node
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int write_rcvrd_mst_node(struct ubifs_info *c,
+				struct ubifs_mst_node *mst)
+{
+	int err = 0, lnum = UBIFS_MST_LNUM, sz = c->mst_node_alsz;
+	__le32 save_flags;
+
+	dbg_rcvry("recovery");
+
+	save_flags = mst->flags;
+	mst->flags |= cpu_to_le32(UBIFS_MST_RCVRY);
+
+	err = ubifs_prepare_node_hmac(c, mst, UBIFS_MST_NODE_SZ,
+				      offsetof(struct ubifs_mst_node, hmac), 1);
+	if (err)
+		goto out;
+	err = ubifs_leb_change(c, lnum, mst, sz);
+	if (err)
+		goto out;
+	err = ubifs_leb_change(c, lnum + 1, mst, sz);
+	if (err)
+		goto out;
+out:
+	mst->flags = save_flags;
+	return err;
+}
+
+/**
+ * ubifs_recover_master_node - recover the master node.
+ * @c: UBIFS file-system description object
+ *
+ * This function recovers the master node from corruption that may occur due to
+ * an unclean unmount.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_recover_master_node(struct ubifs_info *c)
+{
+	void *buf1 = NULL, *buf2 = NULL, *cor1 = NULL, *cor2 = NULL;
+	struct ubifs_mst_node *mst1 = NULL, *mst2 = NULL, *mst;
+	const int sz = c->mst_node_alsz;
+	int err, offs1, offs2;
+
+	dbg_rcvry("recovery");
+
+	err = get_master_node(c, UBIFS_MST_LNUM, &buf1, &mst1, &cor1);
+	if (err)
+		goto out_free;
+
+	err = get_master_node(c, UBIFS_MST_LNUM + 1, &buf2, &mst2, &cor2);
+	if (err)
+		goto out_free;
+
+	if (mst1) {
+		offs1 = (void *)mst1 - buf1;
+		if ((le32_to_cpu(mst1->flags) & UBIFS_MST_RCVRY) &&
+		    (offs1 == 0 && !cor1)) {
+			/*
+			 * mst1 was written by recovery at offset 0 with no
+			 * corruption.
+			 */
+			dbg_rcvry("recovery recovery");
+			mst = mst1;
+		} else if (mst2) {
+			offs2 = (void *)mst2 - buf2;
+			if (offs1 == offs2) {
+				/* Same offset, so must be the same */
+				if (ubifs_compare_master_node(c, mst1, mst2))
+					goto out_err;
+				mst = mst1;
+			} else if (offs2 + sz == offs1) {
+				/* 1st LEB was written, 2nd was not */
+				if (cor1)
+					goto out_err;
+				mst = mst1;
+			} else if (offs1 == 0 &&
+				   c->leb_size - offs2 - sz < sz) {
+				/* 1st LEB was unmapped and written, 2nd not */
+				if (cor1)
+					goto out_err;
+				mst = mst1;
+			} else
+				goto out_err;
+		} else {
+			/*
+			 * 2nd LEB was unmapped and about to be written, so
+			 * there must be only one master node in the first LEB
+			 * and no corruption.
+			 */
+			if (offs1 != 0 || cor1)
+				goto out_err;
+			mst = mst1;
+		}
+	} else {
+		if (!mst2)
+			goto out_err;
+		/*
+		 * 1st LEB was unmapped and about to be written, so there must
+		 * be no room left in 2nd LEB.
+		 */
+		offs2 = (void *)mst2 - buf2;
+		if (offs2 + sz + sz <= c->leb_size)
+			goto out_err;
+		mst = mst2;
+	}
+
+	ubifs_msg(c, "recovered master node from LEB %d",
+		  (mst == mst1 ? UBIFS_MST_LNUM : UBIFS_MST_LNUM + 1));
+
+	memcpy(c->mst_node, mst, UBIFS_MST_NODE_SZ);
+
+	if (c->ro_mount) {
+		/* Read-only mode. Keep a copy for switching to rw mode */
+		c->rcvrd_mst_node = kmalloc(sz, GFP_KERNEL);
+		if (!c->rcvrd_mst_node) {
+			err = -ENOMEM;
+			goto out_free;
+		}
+		memcpy(c->rcvrd_mst_node, c->mst_node, UBIFS_MST_NODE_SZ);
+
+		/*
+		 * We had to recover the master node, which means there was an
+		 * unclean reboot. However, it is possible that the master node
+		 * is clean at this point, i.e., %UBIFS_MST_DIRTY is not set.
+		 * E.g., consider the following chain of events:
+		 *
+		 * 1. UBIFS was cleanly unmounted, so the master node is clean
+		 * 2. UBIFS is being mounted R/W and starts changing the master
+		 *    node in the first (%UBIFS_MST_LNUM). A power cut happens,
+		 *    so this LEB ends up with some amount of garbage at the
+		 *    end.
+		 * 3. UBIFS is being mounted R/O. We reach this place and
+		 *    recover the master node from the second LEB
+		 *    (%UBIFS_MST_LNUM + 1). But we cannot update the media
+		 *    because we are being mounted R/O. We have to defer the
+		 *    operation.
+		 * 4. However, this master node (@c->mst_node) is marked as
+		 *    clean (since the step 1). And if we just return, the
+		 *    mount code will be confused and won't recover the master
+		 *    node when it is re-mounter R/W later.
+		 *
+		 *    Thus, to force the recovery by marking the master node as
+		 *    dirty.
+		 */
+		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
+	} else {
+		/* Write the recovered master node */
+		c->max_sqnum = le64_to_cpu(mst->ch.sqnum) - 1;
+		err = write_rcvrd_mst_node(c, c->mst_node);
+		if (err)
+			goto out_free;
+	}
+
+	vfree(buf2);
+	vfree(buf1);
+
+	return 0;
+
+out_err:
+	err = -EINVAL;
+out_free:
+	ubifs_err(c, "failed to recover master node");
+	if (mst1) {
+		ubifs_err(c, "dumping first master node");
+		ubifs_dump_node(c, mst1, c->leb_size - ((void *)mst1 - buf1));
+	}
+	if (mst2) {
+		ubifs_err(c, "dumping second master node");
+		ubifs_dump_node(c, mst2, c->leb_size - ((void *)mst2 - buf2));
+	}
+	vfree(buf2);
+	vfree(buf1);
+	return err;
+}
+
+/**
+ * ubifs_write_rcvrd_mst_node - write the recovered master node.
+ * @c: UBIFS file-system description object
+ *
+ * This function writes the master node that was recovered during mounting in
+ * read-only mode and must now be written because we are remounting rw.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_write_rcvrd_mst_node(struct ubifs_info *c)
+{
+	int err;
+
+	if (!c->rcvrd_mst_node)
+		return 0;
+	c->rcvrd_mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
+	c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
+	err = write_rcvrd_mst_node(c, c->rcvrd_mst_node);
+	if (err)
+		return err;
+	kfree(c->rcvrd_mst_node);
+	c->rcvrd_mst_node = NULL;
+	return 0;
+}
+
+/**
+ * is_last_write - determine if an offset was in the last write to a LEB.
+ * @c: UBIFS file-system description object
+ * @buf: buffer to check
+ * @offs: offset to check
+ *
+ * This function returns %1 if @offs was in the last write to the LEB whose data
+ * is in @buf, otherwise %0 is returned. The determination is made by checking
+ * for subsequent empty space starting from the next @c->max_write_size
+ * boundary.
+ */
+static int is_last_write(const struct ubifs_info *c, void *buf, int offs)
+{
+	int empty_offs, check_len;
+	uint8_t *p;
+
+	/*
+	 * Round up to the next @c->max_write_size boundary i.e. @offs is in
+	 * the last wbuf written. After that should be empty space.
+	 */
+	empty_offs = ALIGN(offs + 1, c->max_write_size);
+	check_len = c->leb_size - empty_offs;
+	p = buf + empty_offs - offs;
+	return is_empty(p, check_len);
+}
+
+/**
+ * clean_buf - clean the data from an LEB sitting in a buffer.
+ * @c: UBIFS file-system description object
+ * @buf: buffer to clean
+ * @lnum: LEB number to clean
+ * @offs: offset from which to clean
+ * @len: length of buffer
+ *
+ * This function pads up to the next min_io_size boundary (if there is one) and
+ * sets empty space to all 0xff. @buf, @offs and @len are updated to the next
+ * @c->min_io_size boundary.
+ */
+static void clean_buf(const struct ubifs_info *c, void **buf, int lnum,
+		      int *offs, int *len)
+{
+	int empty_offs, pad_len;
+
+	dbg_rcvry("cleaning corruption at %d:%d", lnum, *offs);
+
+	ubifs_assert(c, !(*offs & 7));
+	empty_offs = ALIGN(*offs, c->min_io_size);
+	pad_len = empty_offs - *offs;
+	ubifs_pad(c, *buf, pad_len);
+	*offs += pad_len;
+	*buf += pad_len;
+	*len -= pad_len;
+	memset(*buf, 0xff, c->leb_size - empty_offs);
+}
+
+/**
+ * no_more_nodes - determine if there are no more nodes in a buffer.
+ * @c: UBIFS file-system description object
+ * @buf: buffer to check
+ * @len: length of buffer
+ * @lnum: LEB number of the LEB from which @buf was read
+ * @offs: offset from which @buf was read
+ *
+ * This function ensures that the corrupted node at @offs is the last thing
+ * written to a LEB. This function returns %1 if more data is not found and
+ * %0 if more data is found.
+ */
+static int no_more_nodes(const struct ubifs_info *c, void *buf, int len,
+			int lnum, int offs)
+{
+	struct ubifs_ch *ch = buf;
+	int skip, dlen = le32_to_cpu(ch->len);
+
+	/* Check for empty space after the corrupt node's common header */
+	skip = ALIGN(offs + UBIFS_CH_SZ, c->max_write_size) - offs;
+	if (is_empty(buf + skip, len - skip))
+		return 1;
+	/*
+	 * The area after the common header size is not empty, so the common
+	 * header must be intact. Check it.
+	 */
+	if (ubifs_check_node(c, buf, len, lnum, offs, 1, 0) != -EUCLEAN) {
+		dbg_rcvry("unexpected bad common header at %d:%d", lnum, offs);
+		return 0;
+	}
+	/* Now we know the corrupt node's length we can skip over it */
+	skip = ALIGN(offs + dlen, c->max_write_size) - offs;
+	/* After which there should be empty space */
+	if (is_empty(buf + skip, len - skip))
+		return 1;
+	dbg_rcvry("unexpected data at %d:%d", lnum, offs + skip);
+	return 0;
+}
+
+/**
+ * fix_unclean_leb - fix an unclean LEB.
+ * @c: UBIFS file-system description object
+ * @sleb: scanned LEB information
+ * @start: offset where scan started
+ */
+static int fix_unclean_leb(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
+			   int start)
+{
+	int lnum = sleb->lnum, endpt = start;
+
+	/* Get the end offset of the last node we are keeping */
+	if (!list_empty(&sleb->nodes)) {
+		struct ubifs_scan_node *snod;
+
+		snod = list_entry(sleb->nodes.prev,
+				  struct ubifs_scan_node, list);
+		endpt = snod->offs + snod->len;
+	}
+
+	if (c->ro_mount && !c->remounting_rw) {
+		/* Add to recovery list */
+		struct ubifs_unclean_leb *ucleb;
+
+		dbg_rcvry("need to fix LEB %d start %d endpt %d",
+			  lnum, start, sleb->endpt);
+		ucleb = kzalloc(sizeof(struct ubifs_unclean_leb), GFP_NOFS);
+		if (!ucleb)
+			return -ENOMEM;
+		ucleb->lnum = lnum;
+		ucleb->endpt = endpt;
+		list_add_tail(&ucleb->list, &c->unclean_leb_list);
+	} else {
+		/* Write the fixed LEB back to flash */
+		int err;
+
+		dbg_rcvry("fixing LEB %d start %d endpt %d",
+			  lnum, start, sleb->endpt);
+		if (endpt == 0) {
+			err = ubifs_leb_unmap(c, lnum);
+			if (err)
+				return err;
+		} else {
+			int len = ALIGN(endpt, c->min_io_size);
+
+			if (start) {
+				err = ubifs_leb_read(c, lnum, sleb->buf, 0,
+						     start, 1);
+				if (err)
+					return err;
+			}
+			/* Pad to min_io_size */
+			if (len > endpt) {
+				int pad_len = len - ALIGN(endpt, 8);
+
+				if (pad_len > 0) {
+					void *buf = sleb->buf + len - pad_len;
+
+					ubifs_pad(c, buf, pad_len);
+				}
+			}
+			err = ubifs_leb_change(c, lnum, sleb->buf, len);
+			if (err)
+				return err;
+		}
+	}
+	return 0;
+}
+
+/**
+ * drop_last_group - drop the last group of nodes.
+ * @sleb: scanned LEB information
+ * @offs: offset of dropped nodes is returned here
+ *
+ * This is a helper function for 'ubifs_recover_leb()' which drops the last
+ * group of nodes of the scanned LEB.
+ */
+static void drop_last_group(struct ubifs_scan_leb *sleb, int *offs)
+{
+	while (!list_empty(&sleb->nodes)) {
+		struct ubifs_scan_node *snod;
+		struct ubifs_ch *ch;
+
+		snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
+				  list);
+		ch = snod->node;
+		if (ch->group_type != UBIFS_IN_NODE_GROUP)
+			break;
+
+		dbg_rcvry("dropping grouped node at %d:%d",
+			  sleb->lnum, snod->offs);
+		*offs = snod->offs;
+		list_del(&snod->list);
+		kfree(snod);
+		sleb->nodes_cnt -= 1;
+	}
+}
+
+/**
+ * drop_last_node - drop the last node.
+ * @sleb: scanned LEB information
+ * @offs: offset of dropped nodes is returned here
+ *
+ * This is a helper function for 'ubifs_recover_leb()' which drops the last
+ * node of the scanned LEB.
+ */
+static void drop_last_node(struct ubifs_scan_leb *sleb, int *offs)
+{
+	struct ubifs_scan_node *snod;
+
+	if (!list_empty(&sleb->nodes)) {
+		snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
+				  list);
+
+		dbg_rcvry("dropping last node at %d:%d",
+			  sleb->lnum, snod->offs);
+		*offs = snod->offs;
+		list_del(&snod->list);
+		kfree(snod);
+		sleb->nodes_cnt -= 1;
+	}
+}
+
+/**
+ * ubifs_recover_leb - scan and recover a LEB.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number
+ * @offs: offset
+ * @sbuf: LEB-sized buffer to use
+ * @jhead: journal head number this LEB belongs to (%-1 if the LEB does not
+ *         belong to any journal head)
+ *
+ * This function does a scan of a LEB, but caters for errors that might have
+ * been caused by the unclean unmount from which we are attempting to recover.
+ * Returns the scanned information on success and a negative error code on
+ * failure.
+ */
+struct ubifs_scan_leb *ubifs_recover_leb(struct ubifs_info *c, int lnum,
+					 int offs, void *sbuf, int jhead)
+{
+	int ret = 0, err, len = c->leb_size - offs, start = offs, min_io_unit;
+	int grouped = jhead == -1 ? 0 : c->jheads[jhead].grouped;
+	struct ubifs_scan_leb *sleb;
+	void *buf = sbuf + offs;
+
+	dbg_rcvry("%d:%d, jhead %d, grouped %d", lnum, offs, jhead, grouped);
+
+	sleb = ubifs_start_scan(c, lnum, offs, sbuf);
+	if (IS_ERR(sleb))
+		return sleb;
+
+	ubifs_assert(c, len >= 8);
+	while (len >= 8) {
+		dbg_scan("look at LEB %d:%d (%d bytes left)",
+			 lnum, offs, len);
+
+		cond_resched();
+
+		/*
+		 * Scan quietly until there is an error from which we cannot
+		 * recover
+		 */
+		ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1);
+		if (ret == SCANNED_A_NODE) {
+			/* A valid node, and not a padding node */
+			struct ubifs_ch *ch = buf;
+			int node_len;
+
+			err = ubifs_add_snod(c, sleb, buf, offs);
+			if (err)
+				goto error;
+			node_len = ALIGN(le32_to_cpu(ch->len), 8);
+			offs += node_len;
+			buf += node_len;
+			len -= node_len;
+		} else if (ret > 0) {
+			/* Padding bytes or a valid padding node */
+			offs += ret;
+			buf += ret;
+			len -= ret;
+		} else if (ret == SCANNED_EMPTY_SPACE ||
+			   ret == SCANNED_GARBAGE     ||
+			   ret == SCANNED_A_BAD_PAD_NODE ||
+			   ret == SCANNED_A_CORRUPT_NODE) {
+			dbg_rcvry("found corruption (%d) at %d:%d",
+				  ret, lnum, offs);
+			break;
+		} else {
+			ubifs_err(c, "unexpected return value %d", ret);
+			err = -EINVAL;
+			goto error;
+		}
+	}
+
+	if (ret == SCANNED_GARBAGE || ret == SCANNED_A_BAD_PAD_NODE) {
+		if (!is_last_write(c, buf, offs))
+			goto corrupted_rescan;
+	} else if (ret == SCANNED_A_CORRUPT_NODE) {
+		if (!no_more_nodes(c, buf, len, lnum, offs))
+			goto corrupted_rescan;
+	} else if (!is_empty(buf, len)) {
+		if (!is_last_write(c, buf, offs)) {
+			int corruption = first_non_ff(buf, len);
+
+			/*
+			 * See header comment for this file for more
+			 * explanations about the reasons we have this check.
+			 */
+			ubifs_err(c, "corrupt empty space LEB %d:%d, corruption starts at %d",
+				  lnum, offs, corruption);
+			/* Make sure we dump interesting non-0xFF data */
+			offs += corruption;
+			buf += corruption;
+			goto corrupted;
+		}
+	}
+
+	min_io_unit = round_down(offs, c->min_io_size);
+	if (grouped)
+		/*
+		 * If nodes are grouped, always drop the incomplete group at
+		 * the end.
+		 */
+		drop_last_group(sleb, &offs);
+
+	if (jhead == GCHD) {
+		/*
+		 * If this LEB belongs to the GC head then while we are in the
+		 * middle of the same min. I/O unit keep dropping nodes. So
+		 * basically, what we want is to make sure that the last min.
+		 * I/O unit where we saw the corruption is dropped completely
+		 * with all the uncorrupted nodes which may possibly sit there.
+		 *
+		 * In other words, let's name the min. I/O unit where the
+		 * corruption starts B, and the previous min. I/O unit A. The
+		 * below code tries to deal with a situation when half of B
+		 * contains valid nodes or the end of a valid node, and the
+		 * second half of B contains corrupted data or garbage. This
+		 * means that UBIFS had been writing to B just before the power
+		 * cut happened. I do not know how realistic is this scenario
+		 * that half of the min. I/O unit had been written successfully
+		 * and the other half not, but this is possible in our 'failure
+		 * mode emulation' infrastructure at least.
+		 *
+		 * So what is the problem, why we need to drop those nodes? Why
+		 * can't we just clean-up the second half of B by putting a
+		 * padding node there? We can, and this works fine with one
+		 * exception which was reproduced with power cut emulation
+		 * testing and happens extremely rarely.
+		 *
+		 * Imagine the file-system is full, we run GC which starts
+		 * moving valid nodes from LEB X to LEB Y (obviously, LEB Y is
+		 * the current GC head LEB). The @c->gc_lnum is -1, which means
+		 * that GC will retain LEB X and will try to continue. Imagine
+		 * that LEB X is currently the dirtiest LEB, and the amount of
+		 * used space in LEB Y is exactly the same as amount of free
+		 * space in LEB X.
+		 *
+		 * And a power cut happens when nodes are moved from LEB X to
+		 * LEB Y. We are here trying to recover LEB Y which is the GC
+		 * head LEB. We find the min. I/O unit B as described above.
+		 * Then we clean-up LEB Y by padding min. I/O unit. And later
+		 * 'ubifs_rcvry_gc_commit()' function fails, because it cannot
+		 * find a dirty LEB which could be GC'd into LEB Y! Even LEB X
+		 * does not match because the amount of valid nodes there does
+		 * not fit the free space in LEB Y any more! And this is
+		 * because of the padding node which we added to LEB Y. The
+		 * user-visible effect of this which I once observed and
+		 * analysed is that we cannot mount the file-system with
+		 * -ENOSPC error.
+		 *
+		 * So obviously, to make sure that situation does not happen we
+		 * should free min. I/O unit B in LEB Y completely and the last
+		 * used min. I/O unit in LEB Y should be A. This is basically
+		 * what the below code tries to do.
+		 */
+		while (offs > min_io_unit)
+			drop_last_node(sleb, &offs);
+	}
+
+	buf = sbuf + offs;
+	len = c->leb_size - offs;
+
+	clean_buf(c, &buf, lnum, &offs, &len);
+	ubifs_end_scan(c, sleb, lnum, offs);
+
+	err = fix_unclean_leb(c, sleb, start);
+	if (err)
+		goto error;
+
+	return sleb;
+
+corrupted_rescan:
+	/* Re-scan the corrupted data with verbose messages */
+	ubifs_err(c, "corruption %d", ret);
+	ubifs_scan_a_node(c, buf, len, lnum, offs, 0);
+corrupted:
+	ubifs_scanned_corruption(c, lnum, offs, buf);
+	err = -EUCLEAN;
+error:
+	ubifs_err(c, "LEB %d scanning failed", lnum);
+	ubifs_scan_destroy(sleb);
+	return ERR_PTR(err);
+}
+
+/**
+ * get_cs_sqnum - get commit start sequence number.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number of commit start node
+ * @offs: offset of commit start node
+ * @cs_sqnum: commit start sequence number is returned here
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int get_cs_sqnum(struct ubifs_info *c, int lnum, int offs,
+			unsigned long long *cs_sqnum)
+{
+	struct ubifs_cs_node *cs_node = NULL;
+	int err, ret;
+
+	dbg_rcvry("at %d:%d", lnum, offs);
+	cs_node = kmalloc(UBIFS_CS_NODE_SZ, GFP_KERNEL);
+	if (!cs_node)
+		return -ENOMEM;
+	if (c->leb_size - offs < UBIFS_CS_NODE_SZ)
+		goto out_err;
+	err = ubifs_leb_read(c, lnum, (void *)cs_node, offs,
+			     UBIFS_CS_NODE_SZ, 0);
+	if (err && err != -EBADMSG)
+		goto out_free;
+	ret = ubifs_scan_a_node(c, cs_node, UBIFS_CS_NODE_SZ, lnum, offs, 0);
+	if (ret != SCANNED_A_NODE) {
+		ubifs_err(c, "Not a valid node");
+		goto out_err;
+	}
+	if (cs_node->ch.node_type != UBIFS_CS_NODE) {
+		ubifs_err(c, "Not a CS node, type is %d", cs_node->ch.node_type);
+		goto out_err;
+	}
+	if (le64_to_cpu(cs_node->cmt_no) != c->cmt_no) {
+		ubifs_err(c, "CS node cmt_no %llu != current cmt_no %llu",
+			  (unsigned long long)le64_to_cpu(cs_node->cmt_no),
+			  c->cmt_no);
+		goto out_err;
+	}
+	*cs_sqnum = le64_to_cpu(cs_node->ch.sqnum);
+	dbg_rcvry("commit start sqnum %llu", *cs_sqnum);
+	kfree(cs_node);
+	return 0;
+
+out_err:
+	err = -EINVAL;
+out_free:
+	ubifs_err(c, "failed to get CS sqnum");
+	kfree(cs_node);
+	return err;
+}
+
+/**
+ * ubifs_recover_log_leb - scan and recover a log LEB.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number
+ * @offs: offset
+ * @sbuf: LEB-sized buffer to use
+ *
+ * This function does a scan of a LEB, but caters for errors that might have
+ * been caused by unclean reboots from which we are attempting to recover
+ * (assume that only the last log LEB can be corrupted by an unclean reboot).
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+struct ubifs_scan_leb *ubifs_recover_log_leb(struct ubifs_info *c, int lnum,
+					     int offs, void *sbuf)
+{
+	struct ubifs_scan_leb *sleb;
+	int next_lnum;
+
+	dbg_rcvry("LEB %d", lnum);
+	next_lnum = lnum + 1;
+	if (next_lnum >= UBIFS_LOG_LNUM + c->log_lebs)
+		next_lnum = UBIFS_LOG_LNUM;
+	if (next_lnum != c->ltail_lnum) {
+		/*
+		 * We can only recover at the end of the log, so check that the
+		 * next log LEB is empty or out of date.
+		 */
+		sleb = ubifs_scan(c, next_lnum, 0, sbuf, 0);
+		if (IS_ERR(sleb))
+			return sleb;
+		if (sleb->nodes_cnt) {
+			struct ubifs_scan_node *snod;
+			unsigned long long cs_sqnum = c->cs_sqnum;
+
+			snod = list_entry(sleb->nodes.next,
+					  struct ubifs_scan_node, list);
+			if (cs_sqnum == 0) {
+				int err;
+
+				err = get_cs_sqnum(c, lnum, offs, &cs_sqnum);
+				if (err) {
+					ubifs_scan_destroy(sleb);
+					return ERR_PTR(err);
+				}
+			}
+			if (snod->sqnum > cs_sqnum) {
+				ubifs_err(c, "unrecoverable log corruption in LEB %d",
+					  lnum);
+				ubifs_scan_destroy(sleb);
+				return ERR_PTR(-EUCLEAN);
+			}
+		}
+		ubifs_scan_destroy(sleb);
+	}
+	return ubifs_recover_leb(c, lnum, offs, sbuf, -1);
+}
+
+/**
+ * recover_head - recover a head.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number of head to recover
+ * @offs: offset of head to recover
+ * @sbuf: LEB-sized buffer to use
+ *
+ * This function ensures that there is no data on the flash at a head location.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int recover_head(struct ubifs_info *c, int lnum, int offs, void *sbuf)
+{
+	int len = c->max_write_size, err;
+
+	if (offs + len > c->leb_size)
+		len = c->leb_size - offs;
+
+	if (!len)
+		return 0;
+
+	/* Read at the head location and check it is empty flash */
+	err = ubifs_leb_read(c, lnum, sbuf, offs, len, 1);
+	if (err || !is_empty(sbuf, len)) {
+		dbg_rcvry("cleaning head at %d:%d", lnum, offs);
+		if (offs == 0)
+			return ubifs_leb_unmap(c, lnum);
+		err = ubifs_leb_read(c, lnum, sbuf, 0, offs, 1);
+		if (err)
+			return err;
+		return ubifs_leb_change(c, lnum, sbuf, offs);
+	}
+
+	return 0;
+}
+
+/**
+ * ubifs_recover_inl_heads - recover index and LPT heads.
+ * @c: UBIFS file-system description object
+ * @sbuf: LEB-sized buffer to use
+ *
+ * This function ensures that there is no data on the flash at the index and
+ * LPT head locations.
+ *
+ * This deals with the recovery of a half-completed journal commit. UBIFS is
+ * careful never to overwrite the last version of the index or the LPT. Because
+ * the index and LPT are wandering trees, data from a half-completed commit will
+ * not be referenced anywhere in UBIFS. The data will be either in LEBs that are
+ * assumed to be empty and will be unmapped anyway before use, or in the index
+ * and LPT heads.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_recover_inl_heads(struct ubifs_info *c, void *sbuf)
+{
+	int err;
+
+	ubifs_assert(c, !c->ro_mount || c->remounting_rw);
+
+	dbg_rcvry("checking index head at %d:%d", c->ihead_lnum, c->ihead_offs);
+	err = recover_head(c, c->ihead_lnum, c->ihead_offs, sbuf);
+	if (err)
+		return err;
+
+	dbg_rcvry("checking LPT head at %d:%d", c->nhead_lnum, c->nhead_offs);
+
+	return recover_head(c, c->nhead_lnum, c->nhead_offs, sbuf);
+}
+
+/**
+ * clean_an_unclean_leb - read and write a LEB to remove corruption.
+ * @c: UBIFS file-system description object
+ * @ucleb: unclean LEB information
+ * @sbuf: LEB-sized buffer to use
+ *
+ * This function reads a LEB up to a point pre-determined by the mount recovery,
+ * checks the nodes, and writes the result back to the flash, thereby cleaning
+ * off any following corruption, or non-fatal ECC errors.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int clean_an_unclean_leb(struct ubifs_info *c,
+				struct ubifs_unclean_leb *ucleb, void *sbuf)
+{
+	int err, lnum = ucleb->lnum, offs = 0, len = ucleb->endpt, quiet = 1;
+	void *buf = sbuf;
+
+	dbg_rcvry("LEB %d len %d", lnum, len);
+
+	if (len == 0) {
+		/* Nothing to read, just unmap it */
+		return ubifs_leb_unmap(c, lnum);
+	}
+
+	err = ubifs_leb_read(c, lnum, buf, offs, len, 0);
+	if (err && err != -EBADMSG)
+		return err;
+
+	while (len >= 8) {
+		int ret;
+
+		cond_resched();
+
+		/* Scan quietly until there is an error */
+		ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet);
+
+		if (ret == SCANNED_A_NODE) {
+			/* A valid node, and not a padding node */
+			struct ubifs_ch *ch = buf;
+			int node_len;
+
+			node_len = ALIGN(le32_to_cpu(ch->len), 8);
+			offs += node_len;
+			buf += node_len;
+			len -= node_len;
+			continue;
+		}
+
+		if (ret > 0) {
+			/* Padding bytes or a valid padding node */
+			offs += ret;
+			buf += ret;
+			len -= ret;
+			continue;
+		}
+
+		if (ret == SCANNED_EMPTY_SPACE) {
+			ubifs_err(c, "unexpected empty space at %d:%d",
+				  lnum, offs);
+			return -EUCLEAN;
+		}
+
+		if (quiet) {
+			/* Redo the last scan but noisily */
+			quiet = 0;
+			continue;
+		}
+
+		ubifs_scanned_corruption(c, lnum, offs, buf);
+		return -EUCLEAN;
+	}
+
+	/* Pad to min_io_size */
+	len = ALIGN(ucleb->endpt, c->min_io_size);
+	if (len > ucleb->endpt) {
+		int pad_len = len - ALIGN(ucleb->endpt, 8);
+
+		if (pad_len > 0) {
+			buf = c->sbuf + len - pad_len;
+			ubifs_pad(c, buf, pad_len);
+		}
+	}
+
+	/* Write back the LEB atomically */
+	err = ubifs_leb_change(c, lnum, sbuf, len);
+	if (err)
+		return err;
+
+	dbg_rcvry("cleaned LEB %d", lnum);
+
+	return 0;
+}
+
+/**
+ * ubifs_clean_lebs - clean LEBs recovered during read-only mount.
+ * @c: UBIFS file-system description object
+ * @sbuf: LEB-sized buffer to use
+ *
+ * This function cleans a LEB identified during recovery that needs to be
+ * written but was not because UBIFS was mounted read-only. This happens when
+ * remounting to read-write mode.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_clean_lebs(struct ubifs_info *c, void *sbuf)
+{
+	dbg_rcvry("recovery");
+	while (!list_empty(&c->unclean_leb_list)) {
+		struct ubifs_unclean_leb *ucleb;
+		int err;
+
+		ucleb = list_entry(c->unclean_leb_list.next,
+				   struct ubifs_unclean_leb, list);
+		err = clean_an_unclean_leb(c, ucleb, sbuf);
+		if (err)
+			return err;
+		list_del(&ucleb->list);
+		kfree(ucleb);
+	}
+	return 0;
+}
+
+/**
+ * grab_empty_leb - grab an empty LEB to use as GC LEB and run commit.
+ * @c: UBIFS file-system description object
+ *
+ * This is a helper function for 'ubifs_rcvry_gc_commit()' which grabs an empty
+ * LEB to be used as GC LEB (@c->gc_lnum), and then runs the commit. Returns
+ * zero in case of success and a negative error code in case of failure.
+ */
+static int grab_empty_leb(struct ubifs_info *c)
+{
+	int lnum, err;
+
+	/*
+	 * Note, it is very important to first search for an empty LEB and then
+	 * run the commit, not vice-versa. The reason is that there might be
+	 * only one empty LEB at the moment, the one which has been the
+	 * @c->gc_lnum just before the power cut happened. During the regular
+	 * UBIFS operation (not now) @c->gc_lnum is marked as "taken", so no
+	 * one but GC can grab it. But at this moment this single empty LEB is
+	 * not marked as taken, so if we run commit - what happens? Right, the
+	 * commit will grab it and write the index there. Remember that the
+	 * index always expands as long as there is free space, and it only
+	 * starts consolidating when we run out of space.
+	 *
+	 * IOW, if we run commit now, we might not be able to find a free LEB
+	 * after this.
+	 */
+	lnum = ubifs_find_free_leb_for_idx(c);
+	if (lnum < 0) {
+		ubifs_err(c, "could not find an empty LEB");
+		ubifs_dump_lprops(c);
+		ubifs_dump_budg(c, &c->bi);
+		return lnum;
+	}
+
+	/* Reset the index flag */
+	err = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
+				  LPROPS_INDEX, 0);
+	if (err)
+		return err;
+
+	c->gc_lnum = lnum;
+	dbg_rcvry("found empty LEB %d, run commit", lnum);
+
+	return ubifs_run_commit(c);
+}
+
+/**
+ * ubifs_rcvry_gc_commit - recover the GC LEB number and run the commit.
+ * @c: UBIFS file-system description object
+ *
+ * Out-of-place garbage collection requires always one empty LEB with which to
+ * start garbage collection. The LEB number is recorded in c->gc_lnum and is
+ * written to the master node on unmounting. In the case of an unclean unmount
+ * the value of gc_lnum recorded in the master node is out of date and cannot
+ * be used. Instead, recovery must allocate an empty LEB for this purpose.
+ * However, there may not be enough empty space, in which case it must be
+ * possible to GC the dirtiest LEB into the GC head LEB.
+ *
+ * This function also runs the commit which causes the TNC updates from
+ * size-recovery and orphans to be written to the flash. That is important to
+ * ensure correct replay order for subsequent mounts.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_rcvry_gc_commit(struct ubifs_info *c)
+{
+	struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
+	struct ubifs_lprops lp;
+	int err;
+
+	dbg_rcvry("GC head LEB %d, offs %d", wbuf->lnum, wbuf->offs);
+
+	c->gc_lnum = -1;
+	if (wbuf->lnum == -1 || wbuf->offs == c->leb_size)
+		return grab_empty_leb(c);
+
+	err = ubifs_find_dirty_leb(c, &lp, wbuf->offs, 2);
+	if (err) {
+		if (err != -ENOSPC)
+			return err;
+
+		dbg_rcvry("could not find a dirty LEB");
+		return grab_empty_leb(c);
+	}
+
+	ubifs_assert(c, !(lp.flags & LPROPS_INDEX));
+	ubifs_assert(c, lp.free + lp.dirty >= wbuf->offs);
+
+	/*
+	 * We run the commit before garbage collection otherwise subsequent
+	 * mounts will see the GC and orphan deletion in a different order.
+	 */
+	dbg_rcvry("committing");
+	err = ubifs_run_commit(c);
+	if (err)
+		return err;
+
+	dbg_rcvry("GC'ing LEB %d", lp.lnum);
+	mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
+	err = ubifs_garbage_collect_leb(c, &lp);
+	if (err >= 0) {
+		int err2 = ubifs_wbuf_sync_nolock(wbuf);
+
+		if (err2)
+			err = err2;
+	}
+	mutex_unlock(&wbuf->io_mutex);
+	if (err < 0) {
+		ubifs_err(c, "GC failed, error %d", err);
+		if (err == -EAGAIN)
+			err = -EINVAL;
+		return err;
+	}
+
+	ubifs_assert(c, err == LEB_RETAINED);
+	if (err != LEB_RETAINED)
+		return -EINVAL;
+
+	err = ubifs_leb_unmap(c, c->gc_lnum);
+	if (err)
+		return err;
+
+	dbg_rcvry("allocated LEB %d for GC", lp.lnum);
+	return 0;
+}
+
+/**
+ * struct size_entry - inode size information for recovery.
+ * @rb: link in the RB-tree of sizes
+ * @inum: inode number
+ * @i_size: size on inode
+ * @d_size: maximum size based on data nodes
+ * @exists: indicates whether the inode exists
+ * @inode: inode if pinned in memory awaiting rw mode to fix it
+ */
+struct size_entry {
+	struct rb_node rb;
+	ino_t inum;
+	loff_t i_size;
+	loff_t d_size;
+	int exists;
+	struct inode *inode;
+};
+
+/**
+ * add_ino - add an entry to the size tree.
+ * @c: UBIFS file-system description object
+ * @inum: inode number
+ * @i_size: size on inode
+ * @d_size: maximum size based on data nodes
+ * @exists: indicates whether the inode exists
+ */
+static int add_ino(struct ubifs_info *c, ino_t inum, loff_t i_size,
+		   loff_t d_size, int exists)
+{
+	struct rb_node **p = &c->size_tree.rb_node, *parent = NULL;
+	struct size_entry *e;
+
+	while (*p) {
+		parent = *p;
+		e = rb_entry(parent, struct size_entry, rb);
+		if (inum < e->inum)
+			p = &(*p)->rb_left;
+		else
+			p = &(*p)->rb_right;
+	}
+
+	e = kzalloc(sizeof(struct size_entry), GFP_KERNEL);
+	if (!e)
+		return -ENOMEM;
+
+	e->inum = inum;
+	e->i_size = i_size;
+	e->d_size = d_size;
+	e->exists = exists;
+
+	rb_link_node(&e->rb, parent, p);
+	rb_insert_color(&e->rb, &c->size_tree);
+
+	return 0;
+}
+
+/**
+ * find_ino - find an entry on the size tree.
+ * @c: UBIFS file-system description object
+ * @inum: inode number
+ */
+static struct size_entry *find_ino(struct ubifs_info *c, ino_t inum)
+{
+	struct rb_node *p = c->size_tree.rb_node;
+	struct size_entry *e;
+
+	while (p) {
+		e = rb_entry(p, struct size_entry, rb);
+		if (inum < e->inum)
+			p = p->rb_left;
+		else if (inum > e->inum)
+			p = p->rb_right;
+		else
+			return e;
+	}
+	return NULL;
+}
+
+/**
+ * remove_ino - remove an entry from the size tree.
+ * @c: UBIFS file-system description object
+ * @inum: inode number
+ */
+static void remove_ino(struct ubifs_info *c, ino_t inum)
+{
+	struct size_entry *e = find_ino(c, inum);
+
+	if (!e)
+		return;
+	rb_erase(&e->rb, &c->size_tree);
+	kfree(e);
+}
+
+/**
+ * ubifs_destroy_size_tree - free resources related to the size tree.
+ * @c: UBIFS file-system description object
+ */
+void ubifs_destroy_size_tree(struct ubifs_info *c)
+{
+	struct size_entry *e, *n;
+
+	rbtree_postorder_for_each_entry_safe(e, n, &c->size_tree, rb) {
+		iput(e->inode);
+		kfree(e);
+	}
+
+	c->size_tree = RB_ROOT;
+}
+
+/**
+ * ubifs_recover_size_accum - accumulate inode sizes for recovery.
+ * @c: UBIFS file-system description object
+ * @key: node key
+ * @deletion: node is for a deletion
+ * @new_size: inode size
+ *
+ * This function has two purposes:
+ *     1) to ensure there are no data nodes that fall outside the inode size
+ *     2) to ensure there are no data nodes for inodes that do not exist
+ * To accomplish those purposes, a rb-tree is constructed containing an entry
+ * for each inode number in the journal that has not been deleted, and recording
+ * the size from the inode node, the maximum size of any data node (also altered
+ * by truncations) and a flag indicating a inode number for which no inode node
+ * was present in the journal.
+ *
+ * Note that there is still the possibility that there are data nodes that have
+ * been committed that are beyond the inode size, however the only way to find
+ * them would be to scan the entire index. Alternatively, some provision could
+ * be made to record the size of inodes at the start of commit, which would seem
+ * very cumbersome for a scenario that is quite unlikely and the only negative
+ * consequence of which is wasted space.
+ *
+ * This functions returns %0 on success and a negative error code on failure.
+ */
+int ubifs_recover_size_accum(struct ubifs_info *c, union ubifs_key *key,
+			     int deletion, loff_t new_size)
+{
+	ino_t inum = key_inum(c, key);
+	struct size_entry *e;
+	int err;
+
+	switch (key_type(c, key)) {
+	case UBIFS_INO_KEY:
+		if (deletion)
+			remove_ino(c, inum);
+		else {
+			e = find_ino(c, inum);
+			if (e) {
+				e->i_size = new_size;
+				e->exists = 1;
+			} else {
+				err = add_ino(c, inum, new_size, 0, 1);
+				if (err)
+					return err;
+			}
+		}
+		break;
+	case UBIFS_DATA_KEY:
+		e = find_ino(c, inum);
+		if (e) {
+			if (new_size > e->d_size)
+				e->d_size = new_size;
+		} else {
+			err = add_ino(c, inum, 0, new_size, 0);
+			if (err)
+				return err;
+		}
+		break;
+	case UBIFS_TRUN_KEY:
+		e = find_ino(c, inum);
+		if (e)
+			e->d_size = new_size;
+		break;
+	}
+	return 0;
+}
+
+/**
+ * fix_size_in_place - fix inode size in place on flash.
+ * @c: UBIFS file-system description object
+ * @e: inode size information for recovery
+ */
+static int fix_size_in_place(struct ubifs_info *c, struct size_entry *e)
+{
+	struct ubifs_ino_node *ino = c->sbuf;
+	unsigned char *p;
+	union ubifs_key key;
+	int err, lnum, offs, len;
+	loff_t i_size;
+	uint32_t crc;
+
+	/* Locate the inode node LEB number and offset */
+	ino_key_init(c, &key, e->inum);
+	err = ubifs_tnc_locate(c, &key, ino, &lnum, &offs);
+	if (err)
+		goto out;
+	/*
+	 * If the size recorded on the inode node is greater than the size that
+	 * was calculated from nodes in the journal then don't change the inode.
+	 */
+	i_size = le64_to_cpu(ino->size);
+	if (i_size >= e->d_size)
+		return 0;
+	/* Read the LEB */
+	err = ubifs_leb_read(c, lnum, c->sbuf, 0, c->leb_size, 1);
+	if (err)
+		goto out;
+	/* Change the size field and recalculate the CRC */
+	ino = c->sbuf + offs;
+	ino->size = cpu_to_le64(e->d_size);
+	len = le32_to_cpu(ino->ch.len);
+	crc = crc32(UBIFS_CRC32_INIT, (void *)ino + 8, len - 8);
+	ino->ch.crc = cpu_to_le32(crc);
+	/* Work out where data in the LEB ends and free space begins */
+	p = c->sbuf;
+	len = c->leb_size - 1;
+	while (p[len] == 0xff)
+		len -= 1;
+	len = ALIGN(len + 1, c->min_io_size);
+	/* Atomically write the fixed LEB back again */
+	err = ubifs_leb_change(c, lnum, c->sbuf, len);
+	if (err)
+		goto out;
+	dbg_rcvry("inode %lu at %d:%d size %lld -> %lld",
+		  (unsigned long)e->inum, lnum, offs, i_size, e->d_size);
+	return 0;
+
+out:
+	ubifs_warn(c, "inode %lu failed to fix size %lld -> %lld error %d",
+		   (unsigned long)e->inum, e->i_size, e->d_size, err);
+	return err;
+}
+
+/**
+ * inode_fix_size - fix inode size
+ * @c: UBIFS file-system description object
+ * @e: inode size information for recovery
+ */
+static int inode_fix_size(struct ubifs_info *c, struct size_entry *e)
+{
+	struct inode *inode;
+	struct ubifs_inode *ui;
+	int err;
+
+	if (c->ro_mount)
+		ubifs_assert(c, !e->inode);
+
+	if (e->inode) {
+		/* Remounting rw, pick up inode we stored earlier */
+		inode = e->inode;
+	} else {
+		inode = ubifs_iget(c->vfs_sb, e->inum);
+		if (IS_ERR(inode))
+			return PTR_ERR(inode);
+
+		if (inode->i_size >= e->d_size) {
+			/*
+			 * The original inode in the index already has a size
+			 * big enough, nothing to do
+			 */
+			iput(inode);
+			return 0;
+		}
+
+		dbg_rcvry("ino %lu size %lld -> %lld",
+			  (unsigned long)e->inum,
+			  inode->i_size, e->d_size);
+
+		ui = ubifs_inode(inode);
+
+		inode->i_size = e->d_size;
+		ui->ui_size = e->d_size;
+		ui->synced_i_size = e->d_size;
+
+		e->inode = inode;
+	}
+
+	/*
+	 * In readonly mode just keep the inode pinned in memory until we go
+	 * readwrite. In readwrite mode write the inode to the journal with the
+	 * fixed size.
+	 */
+	if (c->ro_mount)
+		return 0;
+
+	err = ubifs_jnl_write_inode(c, inode);
+
+	iput(inode);
+
+	if (err)
+		return err;
+
+	rb_erase(&e->rb, &c->size_tree);
+	kfree(e);
+
+	return 0;
+}
+
+/**
+ * ubifs_recover_size - recover inode size.
+ * @c: UBIFS file-system description object
+ * @in_place: If true, do a in-place size fixup
+ *
+ * This function attempts to fix inode size discrepancies identified by the
+ * 'ubifs_recover_size_accum()' function.
+ *
+ * This functions returns %0 on success and a negative error code on failure.
+ */
+int ubifs_recover_size(struct ubifs_info *c, bool in_place)
+{
+	struct rb_node *this = rb_first(&c->size_tree);
+
+	while (this) {
+		struct size_entry *e;
+		int err;
+
+		e = rb_entry(this, struct size_entry, rb);
+
+		this = rb_next(this);
+
+		if (!e->exists) {
+			union ubifs_key key;
+
+			ino_key_init(c, &key, e->inum);
+			err = ubifs_tnc_lookup(c, &key, c->sbuf);
+			if (err && err != -ENOENT)
+				return err;
+			if (err == -ENOENT) {
+				/* Remove data nodes that have no inode */
+				dbg_rcvry("removing ino %lu",
+					  (unsigned long)e->inum);
+				err = ubifs_tnc_remove_ino(c, e->inum);
+				if (err)
+					return err;
+			} else {
+				struct ubifs_ino_node *ino = c->sbuf;
+
+				e->exists = 1;
+				e->i_size = le64_to_cpu(ino->size);
+			}
+		}
+
+		if (e->exists && e->i_size < e->d_size) {
+			ubifs_assert(c, !(c->ro_mount && in_place));
+
+			/*
+			 * We found data that is outside the found inode size,
+			 * fixup the inode size
+			 */
+
+			if (in_place) {
+				err = fix_size_in_place(c, e);
+				if (err)
+					return err;
+				iput(e->inode);
+			} else {
+				err = inode_fix_size(c, e);
+				if (err)
+					return err;
+				continue;
+			}
+		}
+
+		rb_erase(&e->rb, &c->size_tree);
+		kfree(e);
+	}
+
+	return 0;
+}
diff --git a/ubifs-utils/libubifs/replay.c b/ubifs-utils/libubifs/replay.c
new file mode 100644
index 00000000..c59d47fe
--- /dev/null
+++ b/ubifs-utils/libubifs/replay.c
@@ -0,0 +1,1250 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file contains journal replay code. It runs when the file-system is being
+ * mounted and requires no locking.
+ *
+ * The larger is the journal, the longer it takes to scan it, so the longer it
+ * takes to mount UBIFS. This is why the journal has limited size which may be
+ * changed depending on the system requirements. But a larger journal gives
+ * faster I/O speed because it writes the index less frequently. So this is a
+ * trade-off. Also, the journal is indexed by the in-memory index (TNC), so the
+ * larger is the journal, the more memory its index may consume.
+ */
+
+#include "ubifs.h"
+#include <linux/list_sort.h>
+#include <crypto/hash.h>
+
+/**
+ * struct replay_entry - replay list entry.
+ * @lnum: logical eraseblock number of the node
+ * @offs: node offset
+ * @len: node length
+ * @deletion: non-zero if this entry corresponds to a node deletion
+ * @sqnum: node sequence number
+ * @list: links the replay list
+ * @key: node key
+ * @nm: directory entry name
+ * @old_size: truncation old size
+ * @new_size: truncation new size
+ *
+ * The replay process first scans all buds and builds the replay list, then
+ * sorts the replay list in nodes sequence number order, and then inserts all
+ * the replay entries to the TNC.
+ */
+struct replay_entry {
+	int lnum;
+	int offs;
+	int len;
+	u8 hash[UBIFS_HASH_ARR_SZ];
+	unsigned int deletion:1;
+	unsigned long long sqnum;
+	struct list_head list;
+	union ubifs_key key;
+	union {
+		struct fscrypt_name nm;
+		struct {
+			loff_t old_size;
+			loff_t new_size;
+		};
+	};
+};
+
+/**
+ * struct bud_entry - entry in the list of buds to replay.
+ * @list: next bud in the list
+ * @bud: bud description object
+ * @sqnum: reference node sequence number
+ * @free: free bytes in the bud
+ * @dirty: dirty bytes in the bud
+ */
+struct bud_entry {
+	struct list_head list;
+	struct ubifs_bud *bud;
+	unsigned long long sqnum;
+	int free;
+	int dirty;
+};
+
+/**
+ * set_bud_lprops - set free and dirty space used by a bud.
+ * @c: UBIFS file-system description object
+ * @b: bud entry which describes the bud
+ *
+ * This function makes sure the LEB properties of bud @b are set correctly
+ * after the replay. Returns zero in case of success and a negative error code
+ * in case of failure.
+ */
+static int set_bud_lprops(struct ubifs_info *c, struct bud_entry *b)
+{
+	const struct ubifs_lprops *lp;
+	int err = 0, dirty;
+
+	ubifs_get_lprops(c);
+
+	lp = ubifs_lpt_lookup_dirty(c, b->bud->lnum);
+	if (IS_ERR(lp)) {
+		err = PTR_ERR(lp);
+		goto out;
+	}
+
+	dirty = lp->dirty;
+	if (b->bud->start == 0 && (lp->free != c->leb_size || lp->dirty != 0)) {
+		/*
+		 * The LEB was added to the journal with a starting offset of
+		 * zero which means the LEB must have been empty. The LEB
+		 * property values should be @lp->free == @c->leb_size and
+		 * @lp->dirty == 0, but that is not the case. The reason is that
+		 * the LEB had been garbage collected before it became the bud,
+		 * and there was no commit in between. The garbage collector
+		 * resets the free and dirty space without recording it
+		 * anywhere except lprops, so if there was no commit then
+		 * lprops does not have that information.
+		 *
+		 * We do not need to adjust free space because the scan has told
+		 * us the exact value which is recorded in the replay entry as
+		 * @b->free.
+		 *
+		 * However we do need to subtract from the dirty space the
+		 * amount of space that the garbage collector reclaimed, which
+		 * is the whole LEB minus the amount of space that was free.
+		 */
+		dbg_mnt("bud LEB %d was GC'd (%d free, %d dirty)", b->bud->lnum,
+			lp->free, lp->dirty);
+		dbg_gc("bud LEB %d was GC'd (%d free, %d dirty)", b->bud->lnum,
+			lp->free, lp->dirty);
+		dirty -= c->leb_size - lp->free;
+		/*
+		 * If the replay order was perfect the dirty space would now be
+		 * zero. The order is not perfect because the journal heads
+		 * race with each other. This is not a problem but is does mean
+		 * that the dirty space may temporarily exceed c->leb_size
+		 * during the replay.
+		 */
+		if (dirty != 0)
+			dbg_mnt("LEB %d lp: %d free %d dirty replay: %d free %d dirty",
+				b->bud->lnum, lp->free, lp->dirty, b->free,
+				b->dirty);
+	}
+	lp = ubifs_change_lp(c, lp, b->free, dirty + b->dirty,
+			     lp->flags | LPROPS_TAKEN, 0);
+	if (IS_ERR(lp)) {
+		err = PTR_ERR(lp);
+		goto out;
+	}
+
+	/* Make sure the journal head points to the latest bud */
+	err = ubifs_wbuf_seek_nolock(&c->jheads[b->bud->jhead].wbuf,
+				     b->bud->lnum, c->leb_size - b->free);
+
+out:
+	ubifs_release_lprops(c);
+	return err;
+}
+
+/**
+ * set_buds_lprops - set free and dirty space for all replayed buds.
+ * @c: UBIFS file-system description object
+ *
+ * This function sets LEB properties for all replayed buds. Returns zero in
+ * case of success and a negative error code in case of failure.
+ */
+static int set_buds_lprops(struct ubifs_info *c)
+{
+	struct bud_entry *b;
+	int err;
+
+	list_for_each_entry(b, &c->replay_buds, list) {
+		err = set_bud_lprops(c, b);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+/**
+ * trun_remove_range - apply a replay entry for a truncation to the TNC.
+ * @c: UBIFS file-system description object
+ * @r: replay entry of truncation
+ */
+static int trun_remove_range(struct ubifs_info *c, struct replay_entry *r)
+{
+	unsigned min_blk, max_blk;
+	union ubifs_key min_key, max_key;
+	ino_t ino;
+
+	min_blk = r->new_size / UBIFS_BLOCK_SIZE;
+	if (r->new_size & (UBIFS_BLOCK_SIZE - 1))
+		min_blk += 1;
+
+	max_blk = r->old_size / UBIFS_BLOCK_SIZE;
+	if ((r->old_size & (UBIFS_BLOCK_SIZE - 1)) == 0)
+		max_blk -= 1;
+
+	ino = key_inum(c, &r->key);
+
+	data_key_init(c, &min_key, ino, min_blk);
+	data_key_init(c, &max_key, ino, max_blk);
+
+	return ubifs_tnc_remove_range(c, &min_key, &max_key);
+}
+
+/**
+ * inode_still_linked - check whether inode in question will be re-linked.
+ * @c: UBIFS file-system description object
+ * @rino: replay entry to test
+ *
+ * O_TMPFILE files can be re-linked, this means link count goes from 0 to 1.
+ * This case needs special care, otherwise all references to the inode will
+ * be removed upon the first replay entry of an inode with link count 0
+ * is found.
+ */
+static bool inode_still_linked(struct ubifs_info *c, struct replay_entry *rino)
+{
+	struct replay_entry *r;
+
+	ubifs_assert(c, rino->deletion);
+	ubifs_assert(c, key_type(c, &rino->key) == UBIFS_INO_KEY);
+
+	/*
+	 * Find the most recent entry for the inode behind @rino and check
+	 * whether it is a deletion.
+	 */
+	list_for_each_entry_reverse(r, &c->replay_list, list) {
+		ubifs_assert(c, r->sqnum >= rino->sqnum);
+		if (key_inum(c, &r->key) == key_inum(c, &rino->key) &&
+		    key_type(c, &r->key) == UBIFS_INO_KEY)
+			return r->deletion == 0;
+
+	}
+
+	ubifs_assert(c, 0);
+	return false;
+}
+
+/**
+ * apply_replay_entry - apply a replay entry to the TNC.
+ * @c: UBIFS file-system description object
+ * @r: replay entry to apply
+ *
+ * Apply a replay entry to the TNC.
+ */
+static int apply_replay_entry(struct ubifs_info *c, struct replay_entry *r)
+{
+	int err;
+
+	dbg_mntk(&r->key, "LEB %d:%d len %d deletion %d sqnum %llu key ",
+		 r->lnum, r->offs, r->len, r->deletion, r->sqnum);
+
+	if (is_hash_key(c, &r->key)) {
+		if (r->deletion)
+			err = ubifs_tnc_remove_nm(c, &r->key, &r->nm);
+		else
+			err = ubifs_tnc_add_nm(c, &r->key, r->lnum, r->offs,
+					       r->len, r->hash, &r->nm);
+	} else {
+		if (r->deletion)
+			switch (key_type(c, &r->key)) {
+			case UBIFS_INO_KEY:
+			{
+				ino_t inum = key_inum(c, &r->key);
+
+				if (inode_still_linked(c, r)) {
+					err = 0;
+					break;
+				}
+
+				err = ubifs_tnc_remove_ino(c, inum);
+				break;
+			}
+			case UBIFS_TRUN_KEY:
+				err = trun_remove_range(c, r);
+				break;
+			default:
+				err = ubifs_tnc_remove(c, &r->key);
+				break;
+			}
+		else
+			err = ubifs_tnc_add(c, &r->key, r->lnum, r->offs,
+					    r->len, r->hash);
+		if (err)
+			return err;
+
+		if (c->need_recovery)
+			err = ubifs_recover_size_accum(c, &r->key, r->deletion,
+						       r->new_size);
+	}
+
+	return err;
+}
+
+/**
+ * replay_entries_cmp - compare 2 replay entries.
+ * @priv: UBIFS file-system description object
+ * @a: first replay entry
+ * @b: second replay entry
+ *
+ * This is a comparios function for 'list_sort()' which compares 2 replay
+ * entries @a and @b by comparing their sequence number.  Returns %1 if @a has
+ * greater sequence number and %-1 otherwise.
+ */
+static int replay_entries_cmp(void *priv, const struct list_head *a,
+			      const struct list_head *b)
+{
+	struct ubifs_info *c = priv;
+	struct replay_entry *ra, *rb;
+
+	cond_resched();
+	if (a == b)
+		return 0;
+
+	ra = list_entry(a, struct replay_entry, list);
+	rb = list_entry(b, struct replay_entry, list);
+	ubifs_assert(c, ra->sqnum != rb->sqnum);
+	if (ra->sqnum > rb->sqnum)
+		return 1;
+	return -1;
+}
+
+/**
+ * apply_replay_list - apply the replay list to the TNC.
+ * @c: UBIFS file-system description object
+ *
+ * Apply all entries in the replay list to the TNC. Returns zero in case of
+ * success and a negative error code in case of failure.
+ */
+static int apply_replay_list(struct ubifs_info *c)
+{
+	struct replay_entry *r;
+	int err;
+
+	list_sort(c, &c->replay_list, &replay_entries_cmp);
+
+	list_for_each_entry(r, &c->replay_list, list) {
+		cond_resched();
+
+		err = apply_replay_entry(c, r);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+/**
+ * destroy_replay_list - destroy the replay.
+ * @c: UBIFS file-system description object
+ *
+ * Destroy the replay list.
+ */
+static void destroy_replay_list(struct ubifs_info *c)
+{
+	struct replay_entry *r, *tmp;
+
+	list_for_each_entry_safe(r, tmp, &c->replay_list, list) {
+		if (is_hash_key(c, &r->key))
+			kfree(fname_name(&r->nm));
+		list_del(&r->list);
+		kfree(r);
+	}
+}
+
+/**
+ * insert_node - insert a node to the replay list
+ * @c: UBIFS file-system description object
+ * @lnum: node logical eraseblock number
+ * @offs: node offset
+ * @len: node length
+ * @key: node key
+ * @sqnum: sequence number
+ * @deletion: non-zero if this is a deletion
+ * @used: number of bytes in use in a LEB
+ * @old_size: truncation old size
+ * @new_size: truncation new size
+ *
+ * This function inserts a scanned non-direntry node to the replay list. The
+ * replay list contains @struct replay_entry elements, and we sort this list in
+ * sequence number order before applying it. The replay list is applied at the
+ * very end of the replay process. Since the list is sorted in sequence number
+ * order, the older modifications are applied first. This function returns zero
+ * in case of success and a negative error code in case of failure.
+ */
+static int insert_node(struct ubifs_info *c, int lnum, int offs, int len,
+		       const u8 *hash, union ubifs_key *key,
+		       unsigned long long sqnum, int deletion, int *used,
+		       loff_t old_size, loff_t new_size)
+{
+	struct replay_entry *r;
+
+	dbg_mntk(key, "add LEB %d:%d, key ", lnum, offs);
+
+	if (key_inum(c, key) >= c->highest_inum)
+		c->highest_inum = key_inum(c, key);
+
+	r = kzalloc(sizeof(struct replay_entry), GFP_KERNEL);
+	if (!r)
+		return -ENOMEM;
+
+	if (!deletion)
+		*used += ALIGN(len, 8);
+	r->lnum = lnum;
+	r->offs = offs;
+	r->len = len;
+	ubifs_copy_hash(c, hash, r->hash);
+	r->deletion = !!deletion;
+	r->sqnum = sqnum;
+	key_copy(c, key, &r->key);
+	r->old_size = old_size;
+	r->new_size = new_size;
+
+	list_add_tail(&r->list, &c->replay_list);
+	return 0;
+}
+
+/**
+ * insert_dent - insert a directory entry node into the replay list.
+ * @c: UBIFS file-system description object
+ * @lnum: node logical eraseblock number
+ * @offs: node offset
+ * @len: node length
+ * @key: node key
+ * @name: directory entry name
+ * @nlen: directory entry name length
+ * @sqnum: sequence number
+ * @deletion: non-zero if this is a deletion
+ * @used: number of bytes in use in a LEB
+ *
+ * This function inserts a scanned directory entry node or an extended
+ * attribute entry to the replay list. Returns zero in case of success and a
+ * negative error code in case of failure.
+ */
+static int insert_dent(struct ubifs_info *c, int lnum, int offs, int len,
+		       const u8 *hash, union ubifs_key *key,
+		       const char *name, int nlen, unsigned long long sqnum,
+		       int deletion, int *used)
+{
+	struct replay_entry *r;
+	char *nbuf;
+
+	dbg_mntk(key, "add LEB %d:%d, key ", lnum, offs);
+	if (key_inum(c, key) >= c->highest_inum)
+		c->highest_inum = key_inum(c, key);
+
+	r = kzalloc(sizeof(struct replay_entry), GFP_KERNEL);
+	if (!r)
+		return -ENOMEM;
+
+	nbuf = kmalloc(nlen + 1, GFP_KERNEL);
+	if (!nbuf) {
+		kfree(r);
+		return -ENOMEM;
+	}
+
+	if (!deletion)
+		*used += ALIGN(len, 8);
+	r->lnum = lnum;
+	r->offs = offs;
+	r->len = len;
+	ubifs_copy_hash(c, hash, r->hash);
+	r->deletion = !!deletion;
+	r->sqnum = sqnum;
+	key_copy(c, key, &r->key);
+	fname_len(&r->nm) = nlen;
+	memcpy(nbuf, name, nlen);
+	nbuf[nlen] = '\0';
+	fname_name(&r->nm) = nbuf;
+
+	list_add_tail(&r->list, &c->replay_list);
+	return 0;
+}
+
+/**
+ * ubifs_validate_entry - validate directory or extended attribute entry node.
+ * @c: UBIFS file-system description object
+ * @dent: the node to validate
+ *
+ * This function validates directory or extended attribute entry node @dent.
+ * Returns zero if the node is all right and a %-EINVAL if not.
+ */
+int ubifs_validate_entry(struct ubifs_info *c,
+			 const struct ubifs_dent_node *dent)
+{
+	int key_type = key_type_flash(c, dent->key);
+	int nlen = le16_to_cpu(dent->nlen);
+
+	if (le32_to_cpu(dent->ch.len) != nlen + UBIFS_DENT_NODE_SZ + 1 ||
+	    dent->type >= UBIFS_ITYPES_CNT ||
+	    nlen > UBIFS_MAX_NLEN || dent->name[nlen] != 0 ||
+	    (key_type == UBIFS_XENT_KEY && strnlen(dent->name, nlen) != nlen) ||
+	    le64_to_cpu(dent->inum) > MAX_INUM) {
+		ubifs_err(c, "bad %s node", key_type == UBIFS_DENT_KEY ?
+			  "directory entry" : "extended attribute entry");
+		return -EINVAL;
+	}
+
+	if (key_type != UBIFS_DENT_KEY && key_type != UBIFS_XENT_KEY) {
+		ubifs_err(c, "bad key type %d", key_type);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * is_last_bud - check if the bud is the last in the journal head.
+ * @c: UBIFS file-system description object
+ * @bud: bud description object
+ *
+ * This function checks if bud @bud is the last bud in its journal head. This
+ * information is then used by 'replay_bud()' to decide whether the bud can
+ * have corruptions or not. Indeed, only last buds can be corrupted by power
+ * cuts. Returns %1 if this is the last bud, and %0 if not.
+ */
+static int is_last_bud(struct ubifs_info *c, struct ubifs_bud *bud)
+{
+	struct ubifs_jhead *jh = &c->jheads[bud->jhead];
+	struct ubifs_bud *next;
+	uint32_t data;
+	int err;
+
+	if (list_is_last(&bud->list, &jh->buds_list))
+		return 1;
+
+	/*
+	 * The following is a quirk to make sure we work correctly with UBIFS
+	 * images used with older UBIFS.
+	 *
+	 * Normally, the last bud will be the last in the journal head's list
+	 * of bud. However, there is one exception if the UBIFS image belongs
+	 * to older UBIFS. This is fairly unlikely: one would need to use old
+	 * UBIFS, then have a power cut exactly at the right point, and then
+	 * try to mount this image with new UBIFS.
+	 *
+	 * The exception is: it is possible to have 2 buds A and B, A goes
+	 * before B, and B is the last, bud B is contains no data, and bud A is
+	 * corrupted at the end. The reason is that in older versions when the
+	 * journal code switched the next bud (from A to B), it first added a
+	 * log reference node for the new bud (B), and only after this it
+	 * synchronized the write-buffer of current bud (A). But later this was
+	 * changed and UBIFS started to always synchronize the write-buffer of
+	 * the bud (A) before writing the log reference for the new bud (B).
+	 *
+	 * But because older UBIFS always synchronized A's write-buffer before
+	 * writing to B, we can recognize this exceptional situation but
+	 * checking the contents of bud B - if it is empty, then A can be
+	 * treated as the last and we can recover it.
+	 *
+	 * TODO: remove this piece of code in a couple of years (today it is
+	 * 16.05.2011).
+	 */
+	next = list_entry(bud->list.next, struct ubifs_bud, list);
+	if (!list_is_last(&next->list, &jh->buds_list))
+		return 0;
+
+	err = ubifs_leb_read(c, next->lnum, (char *)&data, next->start, 4, 1);
+	if (err)
+		return 0;
+
+	return data == 0xFFFFFFFF;
+}
+
+/* authenticate_sleb_hash is split out for stack usage */
+static int noinline_for_stack
+authenticate_sleb_hash(struct ubifs_info *c,
+		       struct shash_desc *log_hash, u8 *hash)
+{
+	SHASH_DESC_ON_STACK(hash_desc, c->hash_tfm);
+
+	hash_desc->tfm = c->hash_tfm;
+
+	ubifs_shash_copy_state(c, log_hash, hash_desc);
+	return crypto_shash_final(hash_desc, hash);
+}
+
+/**
+ * authenticate_sleb - authenticate one scan LEB
+ * @c: UBIFS file-system description object
+ * @sleb: the scan LEB to authenticate
+ * @log_hash:
+ * @is_last: if true, this is the last LEB
+ *
+ * This function iterates over the buds of a single LEB authenticating all buds
+ * with the authentication nodes on this LEB. Authentication nodes are written
+ * after some buds and contain a HMAC covering the authentication node itself
+ * and the buds between the last authentication node and the current
+ * authentication node. It can happen that the last buds cannot be authenticated
+ * because a powercut happened when some nodes were written but not the
+ * corresponding authentication node. This function returns the number of nodes
+ * that could be authenticated or a negative error code.
+ */
+static int authenticate_sleb(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
+			     struct shash_desc *log_hash, int is_last)
+{
+	int n_not_auth = 0;
+	struct ubifs_scan_node *snod;
+	int n_nodes = 0;
+	int err;
+	u8 hash[UBIFS_HASH_ARR_SZ];
+	u8 hmac[UBIFS_HMAC_ARR_SZ];
+
+	if (!ubifs_authenticated(c))
+		return sleb->nodes_cnt;
+
+	list_for_each_entry(snod, &sleb->nodes, list) {
+
+		n_nodes++;
+
+		if (snod->type == UBIFS_AUTH_NODE) {
+			struct ubifs_auth_node *auth = snod->node;
+
+			err = authenticate_sleb_hash(c, log_hash, hash);
+			if (err)
+				goto out;
+
+			err = crypto_shash_tfm_digest(c->hmac_tfm, hash,
+						      c->hash_len, hmac);
+			if (err)
+				goto out;
+
+			err = ubifs_check_hmac(c, auth->hmac, hmac);
+			if (err) {
+				err = -EPERM;
+				goto out;
+			}
+			n_not_auth = 0;
+		} else {
+			err = crypto_shash_update(log_hash, snod->node,
+						  snod->len);
+			if (err)
+				goto out;
+			n_not_auth++;
+		}
+	}
+
+	/*
+	 * A powercut can happen when some nodes were written, but not yet
+	 * the corresponding authentication node. This may only happen on
+	 * the last bud though.
+	 */
+	if (n_not_auth) {
+		if (is_last) {
+			dbg_mnt("%d unauthenticated nodes found on LEB %d, Ignoring them",
+				n_not_auth, sleb->lnum);
+			err = 0;
+		} else {
+			dbg_mnt("%d unauthenticated nodes found on non-last LEB %d",
+				n_not_auth, sleb->lnum);
+			err = -EPERM;
+		}
+	} else {
+		err = 0;
+	}
+out:
+	return err ? err : n_nodes - n_not_auth;
+}
+
+/**
+ * replay_bud - replay a bud logical eraseblock.
+ * @c: UBIFS file-system description object
+ * @b: bud entry which describes the bud
+ *
+ * This function replays bud @bud, recovers it if needed, and adds all nodes
+ * from this bud to the replay list. Returns zero in case of success and a
+ * negative error code in case of failure.
+ */
+static int replay_bud(struct ubifs_info *c, struct bud_entry *b)
+{
+	int is_last = is_last_bud(c, b->bud);
+	int err = 0, used = 0, lnum = b->bud->lnum, offs = b->bud->start;
+	int n_nodes, n = 0;
+	struct ubifs_scan_leb *sleb;
+	struct ubifs_scan_node *snod;
+
+	dbg_mnt("replay bud LEB %d, head %d, offs %d, is_last %d",
+		lnum, b->bud->jhead, offs, is_last);
+
+	if (c->need_recovery && is_last)
+		/*
+		 * Recover only last LEBs in the journal heads, because power
+		 * cuts may cause corruptions only in these LEBs, because only
+		 * these LEBs could possibly be written to at the power cut
+		 * time.
+		 */
+		sleb = ubifs_recover_leb(c, lnum, offs, c->sbuf, b->bud->jhead);
+	else
+		sleb = ubifs_scan(c, lnum, offs, c->sbuf, 0);
+	if (IS_ERR(sleb))
+		return PTR_ERR(sleb);
+
+	n_nodes = authenticate_sleb(c, sleb, b->bud->log_hash, is_last);
+	if (n_nodes < 0) {
+		err = n_nodes;
+		goto out;
+	}
+
+	ubifs_shash_copy_state(c, b->bud->log_hash,
+			       c->jheads[b->bud->jhead].log_hash);
+
+	/*
+	 * The bud does not have to start from offset zero - the beginning of
+	 * the 'lnum' LEB may contain previously committed data. One of the
+	 * things we have to do in replay is to correctly update lprops with
+	 * newer information about this LEB.
+	 *
+	 * At this point lprops thinks that this LEB has 'c->leb_size - offs'
+	 * bytes of free space because it only contain information about
+	 * committed data.
+	 *
+	 * But we know that real amount of free space is 'c->leb_size -
+	 * sleb->endpt', and the space in the 'lnum' LEB between 'offs' and
+	 * 'sleb->endpt' is used by bud data. We have to correctly calculate
+	 * how much of these data are dirty and update lprops with this
+	 * information.
+	 *
+	 * The dirt in that LEB region is comprised of padding nodes, deletion
+	 * nodes, truncation nodes and nodes which are obsoleted by subsequent
+	 * nodes in this LEB. So instead of calculating clean space, we
+	 * calculate used space ('used' variable).
+	 */
+
+	list_for_each_entry(snod, &sleb->nodes, list) {
+		u8 hash[UBIFS_HASH_ARR_SZ];
+		int deletion = 0;
+
+		cond_resched();
+
+		if (snod->sqnum >= SQNUM_WATERMARK) {
+			ubifs_err(c, "file system's life ended");
+			goto out_dump;
+		}
+
+		ubifs_node_calc_hash(c, snod->node, hash);
+
+		if (snod->sqnum > c->max_sqnum)
+			c->max_sqnum = snod->sqnum;
+
+		switch (snod->type) {
+		case UBIFS_INO_NODE:
+		{
+			struct ubifs_ino_node *ino = snod->node;
+			loff_t new_size = le64_to_cpu(ino->size);
+
+			if (le32_to_cpu(ino->nlink) == 0)
+				deletion = 1;
+			err = insert_node(c, lnum, snod->offs, snod->len, hash,
+					  &snod->key, snod->sqnum, deletion,
+					  &used, 0, new_size);
+			break;
+		}
+		case UBIFS_DATA_NODE:
+		{
+			struct ubifs_data_node *dn = snod->node;
+			loff_t new_size = le32_to_cpu(dn->size) +
+					  key_block(c, &snod->key) *
+					  UBIFS_BLOCK_SIZE;
+
+			err = insert_node(c, lnum, snod->offs, snod->len, hash,
+					  &snod->key, snod->sqnum, deletion,
+					  &used, 0, new_size);
+			break;
+		}
+		case UBIFS_DENT_NODE:
+		case UBIFS_XENT_NODE:
+		{
+			struct ubifs_dent_node *dent = snod->node;
+
+			err = ubifs_validate_entry(c, dent);
+			if (err)
+				goto out_dump;
+
+			err = insert_dent(c, lnum, snod->offs, snod->len, hash,
+					  &snod->key, dent->name,
+					  le16_to_cpu(dent->nlen), snod->sqnum,
+					  !le64_to_cpu(dent->inum), &used);
+			break;
+		}
+		case UBIFS_TRUN_NODE:
+		{
+			struct ubifs_trun_node *trun = snod->node;
+			loff_t old_size = le64_to_cpu(trun->old_size);
+			loff_t new_size = le64_to_cpu(trun->new_size);
+			union ubifs_key key;
+
+			/* Validate truncation node */
+			if (old_size < 0 || old_size > c->max_inode_sz ||
+			    new_size < 0 || new_size > c->max_inode_sz ||
+			    old_size <= new_size) {
+				ubifs_err(c, "bad truncation node");
+				goto out_dump;
+			}
+
+			/*
+			 * Create a fake truncation key just to use the same
+			 * functions which expect nodes to have keys.
+			 */
+			trun_key_init(c, &key, le32_to_cpu(trun->inum));
+			err = insert_node(c, lnum, snod->offs, snod->len, hash,
+					  &key, snod->sqnum, 1, &used,
+					  old_size, new_size);
+			break;
+		}
+		case UBIFS_AUTH_NODE:
+			break;
+		default:
+			ubifs_err(c, "unexpected node type %d in bud LEB %d:%d",
+				  snod->type, lnum, snod->offs);
+			err = -EINVAL;
+			goto out_dump;
+		}
+		if (err)
+			goto out;
+
+		n++;
+		if (n == n_nodes)
+			break;
+	}
+
+	ubifs_assert(c, ubifs_search_bud(c, lnum));
+	ubifs_assert(c, sleb->endpt - offs >= used);
+	ubifs_assert(c, sleb->endpt % c->min_io_size == 0);
+
+	b->dirty = sleb->endpt - offs - used;
+	b->free = c->leb_size - sleb->endpt;
+	dbg_mnt("bud LEB %d replied: dirty %d, free %d",
+		lnum, b->dirty, b->free);
+
+out:
+	ubifs_scan_destroy(sleb);
+	return err;
+
+out_dump:
+	ubifs_err(c, "bad node is at LEB %d:%d", lnum, snod->offs);
+	ubifs_dump_node(c, snod->node, c->leb_size - snod->offs);
+	ubifs_scan_destroy(sleb);
+	return -EINVAL;
+}
+
+/**
+ * replay_buds - replay all buds.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+static int replay_buds(struct ubifs_info *c)
+{
+	struct bud_entry *b;
+	int err;
+	unsigned long long prev_sqnum = 0;
+
+	list_for_each_entry(b, &c->replay_buds, list) {
+		err = replay_bud(c, b);
+		if (err)
+			return err;
+
+		ubifs_assert(c, b->sqnum > prev_sqnum);
+		prev_sqnum = b->sqnum;
+	}
+
+	return 0;
+}
+
+/**
+ * destroy_bud_list - destroy the list of buds to replay.
+ * @c: UBIFS file-system description object
+ */
+static void destroy_bud_list(struct ubifs_info *c)
+{
+	struct bud_entry *b;
+
+	while (!list_empty(&c->replay_buds)) {
+		b = list_entry(c->replay_buds.next, struct bud_entry, list);
+		list_del(&b->list);
+		kfree(b);
+	}
+}
+
+/**
+ * add_replay_bud - add a bud to the list of buds to replay.
+ * @c: UBIFS file-system description object
+ * @lnum: bud logical eraseblock number to replay
+ * @offs: bud start offset
+ * @jhead: journal head to which this bud belongs
+ * @sqnum: reference node sequence number
+ *
+ * This function returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+static int add_replay_bud(struct ubifs_info *c, int lnum, int offs, int jhead,
+			  unsigned long long sqnum)
+{
+	struct ubifs_bud *bud;
+	struct bud_entry *b;
+	int err;
+
+	dbg_mnt("add replay bud LEB %d:%d, head %d", lnum, offs, jhead);
+
+	bud = kmalloc(sizeof(struct ubifs_bud), GFP_KERNEL);
+	if (!bud)
+		return -ENOMEM;
+
+	b = kmalloc(sizeof(struct bud_entry), GFP_KERNEL);
+	if (!b) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	bud->lnum = lnum;
+	bud->start = offs;
+	bud->jhead = jhead;
+	bud->log_hash = ubifs_hash_get_desc(c);
+	if (IS_ERR(bud->log_hash)) {
+		err = PTR_ERR(bud->log_hash);
+		goto out;
+	}
+
+	ubifs_shash_copy_state(c, c->log_hash, bud->log_hash);
+
+	ubifs_add_bud(c, bud);
+
+	b->bud = bud;
+	b->sqnum = sqnum;
+	list_add_tail(&b->list, &c->replay_buds);
+
+	return 0;
+out:
+	kfree(bud);
+	kfree(b);
+
+	return err;
+}
+
+/**
+ * validate_ref - validate a reference node.
+ * @c: UBIFS file-system description object
+ * @ref: the reference node to validate
+ *
+ * This function returns %1 if a bud reference already exists for the LEB. %0 is
+ * returned if the reference node is new, otherwise %-EINVAL is returned if
+ * validation failed.
+ */
+static int validate_ref(struct ubifs_info *c, const struct ubifs_ref_node *ref)
+{
+	struct ubifs_bud *bud;
+	int lnum = le32_to_cpu(ref->lnum);
+	unsigned int offs = le32_to_cpu(ref->offs);
+	unsigned int jhead = le32_to_cpu(ref->jhead);
+
+	/*
+	 * ref->offs may point to the end of LEB when the journal head points
+	 * to the end of LEB and we write reference node for it during commit.
+	 * So this is why we require 'offs > c->leb_size'.
+	 */
+	if (jhead >= c->jhead_cnt || lnum >= c->leb_cnt ||
+	    lnum < c->main_first || offs > c->leb_size ||
+	    offs & (c->min_io_size - 1))
+		return -EINVAL;
+
+	/* Make sure we have not already looked at this bud */
+	bud = ubifs_search_bud(c, lnum);
+	if (bud) {
+		if (bud->jhead == jhead && bud->start <= offs)
+			return 1;
+		ubifs_err(c, "bud at LEB %d:%d was already referred", lnum, offs);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/**
+ * replay_log_leb - replay a log logical eraseblock.
+ * @c: UBIFS file-system description object
+ * @lnum: log logical eraseblock to replay
+ * @offs: offset to start replaying from
+ * @sbuf: scan buffer
+ *
+ * This function replays a log LEB and returns zero in case of success, %1 if
+ * this is the last LEB in the log, and a negative error code in case of
+ * failure.
+ */
+static int replay_log_leb(struct ubifs_info *c, int lnum, int offs, void *sbuf)
+{
+	int err;
+	struct ubifs_scan_leb *sleb;
+	struct ubifs_scan_node *snod;
+	const struct ubifs_cs_node *node;
+
+	dbg_mnt("replay log LEB %d:%d", lnum, offs);
+	sleb = ubifs_scan(c, lnum, offs, sbuf, c->need_recovery);
+	if (IS_ERR(sleb)) {
+		if (PTR_ERR(sleb) != -EUCLEAN || !c->need_recovery)
+			return PTR_ERR(sleb);
+		/*
+		 * Note, the below function will recover this log LEB only if
+		 * it is the last, because unclean reboots can possibly corrupt
+		 * only the tail of the log.
+		 */
+		sleb = ubifs_recover_log_leb(c, lnum, offs, sbuf);
+		if (IS_ERR(sleb))
+			return PTR_ERR(sleb);
+	}
+
+	if (sleb->nodes_cnt == 0) {
+		err = 1;
+		goto out;
+	}
+
+	node = sleb->buf;
+	snod = list_entry(sleb->nodes.next, struct ubifs_scan_node, list);
+	if (c->cs_sqnum == 0) {
+		/*
+		 * This is the first log LEB we are looking at, make sure that
+		 * the first node is a commit start node. Also record its
+		 * sequence number so that UBIFS can determine where the log
+		 * ends, because all nodes which were have higher sequence
+		 * numbers.
+		 */
+		if (snod->type != UBIFS_CS_NODE) {
+			ubifs_err(c, "first log node at LEB %d:%d is not CS node",
+				  lnum, offs);
+			goto out_dump;
+		}
+		if (le64_to_cpu(node->cmt_no) != c->cmt_no) {
+			ubifs_err(c, "first CS node at LEB %d:%d has wrong commit number %llu expected %llu",
+				  lnum, offs,
+				  (unsigned long long)le64_to_cpu(node->cmt_no),
+				  c->cmt_no);
+			goto out_dump;
+		}
+
+		c->cs_sqnum = le64_to_cpu(node->ch.sqnum);
+		dbg_mnt("commit start sqnum %llu", c->cs_sqnum);
+
+		err = ubifs_shash_init(c, c->log_hash);
+		if (err)
+			goto out;
+
+		err = ubifs_shash_update(c, c->log_hash, node, UBIFS_CS_NODE_SZ);
+		if (err < 0)
+			goto out;
+	}
+
+	if (snod->sqnum < c->cs_sqnum) {
+		/*
+		 * This means that we reached end of log and now
+		 * look to the older log data, which was already
+		 * committed but the eraseblock was not erased (UBIFS
+		 * only un-maps it). So this basically means we have to
+		 * exit with "end of log" code.
+		 */
+		err = 1;
+		goto out;
+	}
+
+	/* Make sure the first node sits at offset zero of the LEB */
+	if (snod->offs != 0) {
+		ubifs_err(c, "first node is not at zero offset");
+		goto out_dump;
+	}
+
+	list_for_each_entry(snod, &sleb->nodes, list) {
+		cond_resched();
+
+		if (snod->sqnum >= SQNUM_WATERMARK) {
+			ubifs_err(c, "file system's life ended");
+			goto out_dump;
+		}
+
+		if (snod->sqnum < c->cs_sqnum) {
+			ubifs_err(c, "bad sqnum %llu, commit sqnum %llu",
+				  snod->sqnum, c->cs_sqnum);
+			goto out_dump;
+		}
+
+		if (snod->sqnum > c->max_sqnum)
+			c->max_sqnum = snod->sqnum;
+
+		switch (snod->type) {
+		case UBIFS_REF_NODE: {
+			const struct ubifs_ref_node *ref = snod->node;
+
+			err = validate_ref(c, ref);
+			if (err == 1)
+				break; /* Already have this bud */
+			if (err)
+				goto out_dump;
+
+			err = ubifs_shash_update(c, c->log_hash, ref,
+						 UBIFS_REF_NODE_SZ);
+			if (err)
+				goto out;
+
+			err = add_replay_bud(c, le32_to_cpu(ref->lnum),
+					     le32_to_cpu(ref->offs),
+					     le32_to_cpu(ref->jhead),
+					     snod->sqnum);
+			if (err)
+				goto out;
+
+			break;
+		}
+		case UBIFS_CS_NODE:
+			/* Make sure it sits at the beginning of LEB */
+			if (snod->offs != 0) {
+				ubifs_err(c, "unexpected node in log");
+				goto out_dump;
+			}
+			break;
+		default:
+			ubifs_err(c, "unexpected node in log");
+			goto out_dump;
+		}
+	}
+
+	if (sleb->endpt || c->lhead_offs >= c->leb_size) {
+		c->lhead_lnum = lnum;
+		c->lhead_offs = sleb->endpt;
+	}
+
+	err = !sleb->endpt;
+out:
+	ubifs_scan_destroy(sleb);
+	return err;
+
+out_dump:
+	ubifs_err(c, "log error detected while replaying the log at LEB %d:%d",
+		  lnum, offs + snod->offs);
+	ubifs_dump_node(c, snod->node, c->leb_size - snod->offs);
+	ubifs_scan_destroy(sleb);
+	return -EINVAL;
+}
+
+/**
+ * take_ihead - update the status of the index head in lprops to 'taken'.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns the amount of free space in the index head LEB or a
+ * negative error code.
+ */
+static int take_ihead(struct ubifs_info *c)
+{
+	const struct ubifs_lprops *lp;
+	int err, free;
+
+	ubifs_get_lprops(c);
+
+	lp = ubifs_lpt_lookup_dirty(c, c->ihead_lnum);
+	if (IS_ERR(lp)) {
+		err = PTR_ERR(lp);
+		goto out;
+	}
+
+	free = lp->free;
+
+	lp = ubifs_change_lp(c, lp, LPROPS_NC, LPROPS_NC,
+			     lp->flags | LPROPS_TAKEN, 0);
+	if (IS_ERR(lp)) {
+		err = PTR_ERR(lp);
+		goto out;
+	}
+
+	err = free;
+out:
+	ubifs_release_lprops(c);
+	return err;
+}
+
+/**
+ * ubifs_replay_journal - replay journal.
+ * @c: UBIFS file-system description object
+ *
+ * This function scans the journal, replays and cleans it up. It makes sure all
+ * memory data structures related to uncommitted journal are built (dirty TNC
+ * tree, tree of buds, modified lprops, etc).
+ */
+int ubifs_replay_journal(struct ubifs_info *c)
+{
+	int err, lnum, free;
+
+	BUILD_BUG_ON(UBIFS_TRUN_KEY > 5);
+
+	/* Update the status of the index head in lprops to 'taken' */
+	free = take_ihead(c);
+	if (free < 0)
+		return free; /* Error code */
+
+	if (c->ihead_offs != c->leb_size - free) {
+		ubifs_err(c, "bad index head LEB %d:%d", c->ihead_lnum,
+			  c->ihead_offs);
+		return -EINVAL;
+	}
+
+	dbg_mnt("start replaying the journal");
+	c->replaying = 1;
+	lnum = c->ltail_lnum = c->lhead_lnum;
+
+	do {
+		err = replay_log_leb(c, lnum, 0, c->sbuf);
+		if (err == 1) {
+			if (lnum != c->lhead_lnum)
+				/* We hit the end of the log */
+				break;
+
+			/*
+			 * The head of the log must always start with the
+			 * "commit start" node on a properly formatted UBIFS.
+			 * But we found no nodes at all, which means that
+			 * something went wrong and we cannot proceed mounting
+			 * the file-system.
+			 */
+			ubifs_err(c, "no UBIFS nodes found at the log head LEB %d:%d, possibly corrupted",
+				  lnum, 0);
+			err = -EINVAL;
+		}
+		if (err)
+			goto out;
+		lnum = ubifs_next_log_lnum(c, lnum);
+	} while (lnum != c->ltail_lnum);
+
+	err = replay_buds(c);
+	if (err)
+		goto out;
+
+	err = apply_replay_list(c);
+	if (err)
+		goto out;
+
+	err = set_buds_lprops(c);
+	if (err)
+		goto out;
+
+	/*
+	 * UBIFS budgeting calculations use @c->bi.uncommitted_idx variable
+	 * to roughly estimate index growth. Things like @c->bi.min_idx_lebs
+	 * depend on it. This means we have to initialize it to make sure
+	 * budgeting works properly.
+	 */
+	c->bi.uncommitted_idx = atomic_long_read(&c->dirty_zn_cnt);
+	c->bi.uncommitted_idx *= c->max_idx_node_sz;
+
+	ubifs_assert(c, c->bud_bytes <= c->max_bud_bytes || c->need_recovery);
+	dbg_mnt("finished, log head LEB %d:%d, max_sqnum %llu, highest_inum %lu",
+		c->lhead_lnum, c->lhead_offs, c->max_sqnum,
+		(unsigned long)c->highest_inum);
+out:
+	destroy_replay_list(c);
+	destroy_bud_list(c);
+	c->replaying = 0;
+	return err;
+}
diff --git a/ubifs-utils/libubifs/sb.c b/ubifs-utils/libubifs/sb.c
new file mode 100644
index 00000000..e7693b94
--- /dev/null
+++ b/ubifs-utils/libubifs/sb.c
@@ -0,0 +1,956 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ */
+
+/*
+ * This file implements UBIFS superblock. The superblock is stored at the first
+ * LEB of the volume and is never changed by UBIFS. Only user-space tools may
+ * change it. The superblock node mostly contains geometry information.
+ */
+
+#include "ubifs.h"
+#include <linux/slab.h>
+#include <linux/math64.h>
+#include <linux/uuid.h>
+
+/*
+ * Default journal size in logical eraseblocks as a percent of total
+ * flash size.
+ */
+#define DEFAULT_JNL_PERCENT 5
+
+/* Default maximum journal size in bytes */
+#define DEFAULT_MAX_JNL (32*1024*1024)
+
+/* Default indexing tree fanout */
+#define DEFAULT_FANOUT 8
+
+/* Default number of data journal heads */
+#define DEFAULT_JHEADS_CNT 1
+
+/* Default positions of different LEBs in the main area */
+#define DEFAULT_IDX_LEB  0
+#define DEFAULT_DATA_LEB 1
+#define DEFAULT_GC_LEB   2
+
+/* Default number of LEB numbers in LPT's save table */
+#define DEFAULT_LSAVE_CNT 256
+
+/* Default reserved pool size as a percent of maximum free space */
+#define DEFAULT_RP_PERCENT 5
+
+/* The default maximum size of reserved pool in bytes */
+#define DEFAULT_MAX_RP_SIZE (5*1024*1024)
+
+/* Default time granularity in nanoseconds */
+#define DEFAULT_TIME_GRAN 1000000000
+
+static int get_default_compressor(struct ubifs_info *c)
+{
+	if (ubifs_compr_present(c, UBIFS_COMPR_ZSTD))
+		return UBIFS_COMPR_ZSTD;
+
+	if (ubifs_compr_present(c, UBIFS_COMPR_LZO))
+		return UBIFS_COMPR_LZO;
+
+	if (ubifs_compr_present(c, UBIFS_COMPR_ZLIB))
+		return UBIFS_COMPR_ZLIB;
+
+	return UBIFS_COMPR_NONE;
+}
+
+/**
+ * create_default_filesystem - format empty UBI volume.
+ * @c: UBIFS file-system description object
+ *
+ * This function creates default empty file-system. Returns zero in case of
+ * success and a negative error code in case of failure.
+ */
+static int create_default_filesystem(struct ubifs_info *c)
+{
+	struct ubifs_sb_node *sup;
+	struct ubifs_mst_node *mst;
+	struct ubifs_idx_node *idx;
+	struct ubifs_branch *br;
+	struct ubifs_ino_node *ino;
+	struct ubifs_cs_node *cs;
+	union ubifs_key key;
+	int err, tmp, jnl_lebs, log_lebs, max_buds, main_lebs, main_first;
+	int lpt_lebs, lpt_first, orph_lebs, big_lpt, ino_waste, sup_flags = 0;
+	int min_leb_cnt = UBIFS_MIN_LEB_CNT;
+	int idx_node_size;
+	long long tmp64, main_bytes;
+	__le64 tmp_le64;
+	struct timespec64 ts;
+	u8 hash[UBIFS_HASH_ARR_SZ];
+	u8 hash_lpt[UBIFS_HASH_ARR_SZ];
+
+	/* Some functions called from here depend on the @c->key_len filed */
+	c->key_len = UBIFS_SK_LEN;
+
+	/*
+	 * First of all, we have to calculate default file-system geometry -
+	 * log size, journal size, etc.
+	 */
+	if (c->leb_cnt < 0x7FFFFFFF / DEFAULT_JNL_PERCENT)
+		/* We can first multiply then divide and have no overflow */
+		jnl_lebs = c->leb_cnt * DEFAULT_JNL_PERCENT / 100;
+	else
+		jnl_lebs = (c->leb_cnt / 100) * DEFAULT_JNL_PERCENT;
+
+	if (jnl_lebs < UBIFS_MIN_JNL_LEBS)
+		jnl_lebs = UBIFS_MIN_JNL_LEBS;
+	if (jnl_lebs * c->leb_size > DEFAULT_MAX_JNL)
+		jnl_lebs = DEFAULT_MAX_JNL / c->leb_size;
+
+	/*
+	 * The log should be large enough to fit reference nodes for all bud
+	 * LEBs. Because buds do not have to start from the beginning of LEBs
+	 * (half of the LEB may contain committed data), the log should
+	 * generally be larger, make it twice as large.
+	 */
+	tmp = 2 * (c->ref_node_alsz * jnl_lebs) + c->leb_size - 1;
+	log_lebs = tmp / c->leb_size;
+	/* Plus one LEB reserved for commit */
+	log_lebs += 1;
+	if (c->leb_cnt - min_leb_cnt > 8) {
+		/* And some extra space to allow writes while committing */
+		log_lebs += 1;
+		min_leb_cnt += 1;
+	}
+
+	max_buds = jnl_lebs - log_lebs;
+	if (max_buds < UBIFS_MIN_BUD_LEBS)
+		max_buds = UBIFS_MIN_BUD_LEBS;
+
+	/*
+	 * Orphan nodes are stored in a separate area. One node can store a lot
+	 * of orphan inode numbers, but when new orphan comes we just add a new
+	 * orphan node. At some point the nodes are consolidated into one
+	 * orphan node.
+	 */
+	orph_lebs = UBIFS_MIN_ORPH_LEBS;
+	if (c->leb_cnt - min_leb_cnt > 1)
+		/*
+		 * For debugging purposes it is better to have at least 2
+		 * orphan LEBs, because the orphan subsystem would need to do
+		 * consolidations and would be stressed more.
+		 */
+		orph_lebs += 1;
+
+	main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS - log_lebs;
+	main_lebs -= orph_lebs;
+
+	lpt_first = UBIFS_LOG_LNUM + log_lebs;
+	c->lsave_cnt = DEFAULT_LSAVE_CNT;
+	c->max_leb_cnt = c->leb_cnt;
+	err = ubifs_create_dflt_lpt(c, &main_lebs, lpt_first, &lpt_lebs,
+				    &big_lpt, hash_lpt);
+	if (err)
+		return err;
+
+	dbg_gen("LEB Properties Tree created (LEBs %d-%d)", lpt_first,
+		lpt_first + lpt_lebs - 1);
+
+	main_first = c->leb_cnt - main_lebs;
+
+	sup = kzalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_KERNEL);
+	mst = kzalloc(c->mst_node_alsz, GFP_KERNEL);
+	idx_node_size = ubifs_idx_node_sz(c, 1);
+	idx = kzalloc(ALIGN(idx_node_size, c->min_io_size), GFP_KERNEL);
+	ino = kzalloc(ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size), GFP_KERNEL);
+	cs = kzalloc(ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size), GFP_KERNEL);
+
+	if (!sup || !mst || !idx || !ino || !cs) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	/* Create default superblock */
+
+	tmp64 = (long long)max_buds * c->leb_size;
+	if (big_lpt)
+		sup_flags |= UBIFS_FLG_BIGLPT;
+	if (ubifs_default_version > 4)
+		sup_flags |= UBIFS_FLG_DOUBLE_HASH;
+
+	if (ubifs_authenticated(c)) {
+		sup_flags |= UBIFS_FLG_AUTHENTICATION;
+		sup->hash_algo = cpu_to_le16(c->auth_hash_algo);
+		err = ubifs_hmac_wkm(c, sup->hmac_wkm);
+		if (err)
+			goto out;
+	} else {
+		sup->hash_algo = cpu_to_le16(0xffff);
+	}
+
+	sup->ch.node_type  = UBIFS_SB_NODE;
+	sup->key_hash      = UBIFS_KEY_HASH_R5;
+	sup->flags         = cpu_to_le32(sup_flags);
+	sup->min_io_size   = cpu_to_le32(c->min_io_size);
+	sup->leb_size      = cpu_to_le32(c->leb_size);
+	sup->leb_cnt       = cpu_to_le32(c->leb_cnt);
+	sup->max_leb_cnt   = cpu_to_le32(c->max_leb_cnt);
+	sup->max_bud_bytes = cpu_to_le64(tmp64);
+	sup->log_lebs      = cpu_to_le32(log_lebs);
+	sup->lpt_lebs      = cpu_to_le32(lpt_lebs);
+	sup->orph_lebs     = cpu_to_le32(orph_lebs);
+	sup->jhead_cnt     = cpu_to_le32(DEFAULT_JHEADS_CNT);
+	sup->fanout        = cpu_to_le32(DEFAULT_FANOUT);
+	sup->lsave_cnt     = cpu_to_le32(c->lsave_cnt);
+	sup->fmt_version   = cpu_to_le32(ubifs_default_version);
+	sup->time_gran     = cpu_to_le32(DEFAULT_TIME_GRAN);
+	if (c->mount_opts.override_compr)
+		sup->default_compr = cpu_to_le16(c->mount_opts.compr_type);
+	else
+		sup->default_compr = cpu_to_le16(get_default_compressor(c));
+
+	generate_random_uuid(sup->uuid);
+
+	main_bytes = (long long)main_lebs * c->leb_size;
+	tmp64 = div_u64(main_bytes * DEFAULT_RP_PERCENT, 100);
+	if (tmp64 > DEFAULT_MAX_RP_SIZE)
+		tmp64 = DEFAULT_MAX_RP_SIZE;
+	sup->rp_size = cpu_to_le64(tmp64);
+	sup->ro_compat_version = cpu_to_le32(UBIFS_RO_COMPAT_VERSION);
+
+	dbg_gen("default superblock created at LEB 0:0");
+
+	/* Create default master node */
+
+	mst->ch.node_type = UBIFS_MST_NODE;
+	mst->log_lnum     = cpu_to_le32(UBIFS_LOG_LNUM);
+	mst->highest_inum = cpu_to_le64(UBIFS_FIRST_INO);
+	mst->cmt_no       = 0;
+	mst->root_lnum    = cpu_to_le32(main_first + DEFAULT_IDX_LEB);
+	mst->root_offs    = 0;
+	tmp = ubifs_idx_node_sz(c, 1);
+	mst->root_len     = cpu_to_le32(tmp);
+	mst->gc_lnum      = cpu_to_le32(main_first + DEFAULT_GC_LEB);
+	mst->ihead_lnum   = cpu_to_le32(main_first + DEFAULT_IDX_LEB);
+	mst->ihead_offs   = cpu_to_le32(ALIGN(tmp, c->min_io_size));
+	mst->index_size   = cpu_to_le64(ALIGN(tmp, 8));
+	mst->lpt_lnum     = cpu_to_le32(c->lpt_lnum);
+	mst->lpt_offs     = cpu_to_le32(c->lpt_offs);
+	mst->nhead_lnum   = cpu_to_le32(c->nhead_lnum);
+	mst->nhead_offs   = cpu_to_le32(c->nhead_offs);
+	mst->ltab_lnum    = cpu_to_le32(c->ltab_lnum);
+	mst->ltab_offs    = cpu_to_le32(c->ltab_offs);
+	mst->lsave_lnum   = cpu_to_le32(c->lsave_lnum);
+	mst->lsave_offs   = cpu_to_le32(c->lsave_offs);
+	mst->lscan_lnum   = cpu_to_le32(main_first);
+	mst->empty_lebs   = cpu_to_le32(main_lebs - 2);
+	mst->idx_lebs     = cpu_to_le32(1);
+	mst->leb_cnt      = cpu_to_le32(c->leb_cnt);
+	ubifs_copy_hash(c, hash_lpt, mst->hash_lpt);
+
+	/* Calculate lprops statistics */
+	tmp64 = main_bytes;
+	tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size);
+	tmp64 -= ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size);
+	mst->total_free = cpu_to_le64(tmp64);
+
+	tmp64 = ALIGN(ubifs_idx_node_sz(c, 1), c->min_io_size);
+	ino_waste = ALIGN(UBIFS_INO_NODE_SZ, c->min_io_size) -
+			  UBIFS_INO_NODE_SZ;
+	tmp64 += ino_waste;
+	tmp64 -= ALIGN(ubifs_idx_node_sz(c, 1), 8);
+	mst->total_dirty = cpu_to_le64(tmp64);
+
+	/*  The indexing LEB does not contribute to dark space */
+	tmp64 = ((long long)(c->main_lebs - 1) * c->dark_wm);
+	mst->total_dark = cpu_to_le64(tmp64);
+
+	mst->total_used = cpu_to_le64(UBIFS_INO_NODE_SZ);
+
+	dbg_gen("default master node created at LEB %d:0", UBIFS_MST_LNUM);
+
+	/* Create the root indexing node */
+
+	c->key_fmt = UBIFS_SIMPLE_KEY_FMT;
+	c->key_hash = key_r5_hash;
+
+	idx->ch.node_type = UBIFS_IDX_NODE;
+	idx->child_cnt = cpu_to_le16(1);
+	ino_key_init(c, &key, UBIFS_ROOT_INO);
+	br = ubifs_idx_branch(c, idx, 0);
+	key_write_idx(c, &key, &br->key);
+	br->lnum = cpu_to_le32(main_first + DEFAULT_DATA_LEB);
+	br->len  = cpu_to_le32(UBIFS_INO_NODE_SZ);
+
+	dbg_gen("default root indexing node created LEB %d:0",
+		main_first + DEFAULT_IDX_LEB);
+
+	/* Create default root inode */
+
+	ino_key_init_flash(c, &ino->key, UBIFS_ROOT_INO);
+	ino->ch.node_type = UBIFS_INO_NODE;
+	ino->creat_sqnum = cpu_to_le64(++c->max_sqnum);
+	ino->nlink = cpu_to_le32(2);
+
+	ktime_get_coarse_real_ts64(&ts);
+	tmp_le64 = cpu_to_le64(ts.tv_sec);
+	ino->atime_sec   = tmp_le64;
+	ino->ctime_sec   = tmp_le64;
+	ino->mtime_sec   = tmp_le64;
+	ino->atime_nsec  = 0;
+	ino->ctime_nsec  = 0;
+	ino->mtime_nsec  = 0;
+	ino->mode = cpu_to_le32(S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO);
+	ino->size = cpu_to_le64(UBIFS_INO_NODE_SZ);
+
+	/* Set compression enabled by default */
+	ino->flags = cpu_to_le32(UBIFS_COMPR_FL);
+
+	dbg_gen("root inode created at LEB %d:0",
+		main_first + DEFAULT_DATA_LEB);
+
+	/*
+	 * The first node in the log has to be the commit start node. This is
+	 * always the case during normal file-system operation. Write a fake
+	 * commit start node to the log.
+	 */
+
+	cs->ch.node_type = UBIFS_CS_NODE;
+
+	err = ubifs_write_node_hmac(c, sup, UBIFS_SB_NODE_SZ, 0, 0,
+				    offsetof(struct ubifs_sb_node, hmac));
+	if (err)
+		goto out;
+
+	err = ubifs_write_node(c, ino, UBIFS_INO_NODE_SZ,
+			       main_first + DEFAULT_DATA_LEB, 0);
+	if (err)
+		goto out;
+
+	ubifs_node_calc_hash(c, ino, hash);
+	ubifs_copy_hash(c, hash, ubifs_branch_hash(c, br));
+
+	err = ubifs_write_node(c, idx, idx_node_size, main_first + DEFAULT_IDX_LEB, 0);
+	if (err)
+		goto out;
+
+	ubifs_node_calc_hash(c, idx, hash);
+	ubifs_copy_hash(c, hash, mst->hash_root_idx);
+
+	err = ubifs_write_node_hmac(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM, 0,
+		offsetof(struct ubifs_mst_node, hmac));
+	if (err)
+		goto out;
+
+	err = ubifs_write_node_hmac(c, mst, UBIFS_MST_NODE_SZ, UBIFS_MST_LNUM + 1,
+			       0, offsetof(struct ubifs_mst_node, hmac));
+	if (err)
+		goto out;
+
+	err = ubifs_write_node(c, cs, UBIFS_CS_NODE_SZ, UBIFS_LOG_LNUM, 0);
+	if (err)
+		goto out;
+
+	ubifs_msg(c, "default file-system created");
+
+	err = 0;
+out:
+	kfree(sup);
+	kfree(mst);
+	kfree(idx);
+	kfree(ino);
+	kfree(cs);
+
+	return err;
+}
+
+/**
+ * validate_sb - validate superblock node.
+ * @c: UBIFS file-system description object
+ * @sup: superblock node
+ *
+ * This function validates superblock node @sup. Since most of data was read
+ * from the superblock and stored in @c, the function validates fields in @c
+ * instead. Returns zero in case of success and %-EINVAL in case of validation
+ * failure.
+ */
+static int validate_sb(struct ubifs_info *c, struct ubifs_sb_node *sup)
+{
+	long long max_bytes;
+	int err = 1, min_leb_cnt;
+
+	if (!c->key_hash) {
+		err = 2;
+		goto failed;
+	}
+
+	if (sup->key_fmt != UBIFS_SIMPLE_KEY_FMT) {
+		err = 3;
+		goto failed;
+	}
+
+	if (le32_to_cpu(sup->min_io_size) != c->min_io_size) {
+		ubifs_err(c, "min. I/O unit mismatch: %d in superblock, %d real",
+			  le32_to_cpu(sup->min_io_size), c->min_io_size);
+		goto failed;
+	}
+
+	if (le32_to_cpu(sup->leb_size) != c->leb_size) {
+		ubifs_err(c, "LEB size mismatch: %d in superblock, %d real",
+			  le32_to_cpu(sup->leb_size), c->leb_size);
+		goto failed;
+	}
+
+	if (c->log_lebs < UBIFS_MIN_LOG_LEBS ||
+	    c->lpt_lebs < UBIFS_MIN_LPT_LEBS ||
+	    c->orph_lebs < UBIFS_MIN_ORPH_LEBS ||
+	    c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
+		err = 4;
+		goto failed;
+	}
+
+	/*
+	 * Calculate minimum allowed amount of main area LEBs. This is very
+	 * similar to %UBIFS_MIN_LEB_CNT, but we take into account real what we
+	 * have just read from the superblock.
+	 */
+	min_leb_cnt = UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs;
+	min_leb_cnt += c->lpt_lebs + c->orph_lebs + c->jhead_cnt + 6;
+
+	if (c->leb_cnt < min_leb_cnt || c->leb_cnt > c->vi.size) {
+		ubifs_err(c, "bad LEB count: %d in superblock, %d on UBI volume, %d minimum required",
+			  c->leb_cnt, c->vi.size, min_leb_cnt);
+		goto failed;
+	}
+
+	if (c->max_leb_cnt < c->leb_cnt) {
+		ubifs_err(c, "max. LEB count %d less than LEB count %d",
+			  c->max_leb_cnt, c->leb_cnt);
+		goto failed;
+	}
+
+	if (c->main_lebs < UBIFS_MIN_MAIN_LEBS) {
+		ubifs_err(c, "too few main LEBs count %d, must be at least %d",
+			  c->main_lebs, UBIFS_MIN_MAIN_LEBS);
+		goto failed;
+	}
+
+	max_bytes = (long long)c->leb_size * UBIFS_MIN_BUD_LEBS;
+	if (c->max_bud_bytes < max_bytes) {
+		ubifs_err(c, "too small journal (%lld bytes), must be at least %lld bytes",
+			  c->max_bud_bytes, max_bytes);
+		goto failed;
+	}
+
+	max_bytes = (long long)c->leb_size * c->main_lebs;
+	if (c->max_bud_bytes > max_bytes) {
+		ubifs_err(c, "too large journal size (%lld bytes), only %lld bytes available in the main area",
+			  c->max_bud_bytes, max_bytes);
+		goto failed;
+	}
+
+	if (c->jhead_cnt < NONDATA_JHEADS_CNT + 1 ||
+	    c->jhead_cnt > NONDATA_JHEADS_CNT + UBIFS_MAX_JHEADS) {
+		err = 9;
+		goto failed;
+	}
+
+	if (c->fanout < UBIFS_MIN_FANOUT ||
+	    ubifs_idx_node_sz(c, c->fanout) > c->leb_size) {
+		err = 10;
+		goto failed;
+	}
+
+	if (c->lsave_cnt < 0 || (c->lsave_cnt > DEFAULT_LSAVE_CNT &&
+	    c->lsave_cnt > c->max_leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS -
+	    c->log_lebs - c->lpt_lebs - c->orph_lebs)) {
+		err = 11;
+		goto failed;
+	}
+
+	if (UBIFS_SB_LEBS + UBIFS_MST_LEBS + c->log_lebs + c->lpt_lebs +
+	    c->orph_lebs + c->main_lebs != c->leb_cnt) {
+		err = 12;
+		goto failed;
+	}
+
+	if (c->default_compr >= UBIFS_COMPR_TYPES_CNT) {
+		err = 13;
+		goto failed;
+	}
+
+	if (c->rp_size < 0 || max_bytes < c->rp_size) {
+		err = 14;
+		goto failed;
+	}
+
+	if (le32_to_cpu(sup->time_gran) > 1000000000 ||
+	    le32_to_cpu(sup->time_gran) < 1) {
+		err = 15;
+		goto failed;
+	}
+
+	if (!c->double_hash && c->fmt_version >= 5) {
+		err = 16;
+		goto failed;
+	}
+
+	if (c->encrypted && c->fmt_version < 5) {
+		err = 17;
+		goto failed;
+	}
+
+	return 0;
+
+failed:
+	ubifs_err(c, "bad superblock, error %d", err);
+	ubifs_dump_node(c, sup, ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size));
+	return -EINVAL;
+}
+
+/**
+ * ubifs_read_sb_node - read superblock node.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns a pointer to the superblock node or a negative error
+ * code. Note, the user of this function is responsible of kfree()'ing the
+ * returned superblock buffer.
+ */
+static struct ubifs_sb_node *ubifs_read_sb_node(struct ubifs_info *c)
+{
+	struct ubifs_sb_node *sup;
+	int err;
+
+	sup = kmalloc(ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size), GFP_NOFS);
+	if (!sup)
+		return ERR_PTR(-ENOMEM);
+
+	err = ubifs_read_node(c, sup, UBIFS_SB_NODE, UBIFS_SB_NODE_SZ,
+			      UBIFS_SB_LNUM, 0);
+	if (err) {
+		kfree(sup);
+		return ERR_PTR(err);
+	}
+
+	return sup;
+}
+
+static int authenticate_sb_node(struct ubifs_info *c,
+				const struct ubifs_sb_node *sup)
+{
+	unsigned int sup_flags = le32_to_cpu(sup->flags);
+	u8 hmac_wkm[UBIFS_HMAC_ARR_SZ];
+	int authenticated = !!(sup_flags & UBIFS_FLG_AUTHENTICATION);
+	int hash_algo;
+	int err;
+
+	if (c->authenticated && !authenticated) {
+		ubifs_err(c, "authenticated FS forced, but found FS without authentication");
+		return -EINVAL;
+	}
+
+	if (!c->authenticated && authenticated) {
+		ubifs_err(c, "authenticated FS found, but no key given");
+		return -EINVAL;
+	}
+
+	ubifs_msg(c, "Mounting in %sauthenticated mode",
+		  c->authenticated ? "" : "un");
+
+	if (!c->authenticated)
+		return 0;
+
+	if (!IS_ENABLED(CONFIG_UBIFS_FS_AUTHENTICATION))
+		return -EOPNOTSUPP;
+
+	hash_algo = le16_to_cpu(sup->hash_algo);
+	if (hash_algo >= HASH_ALGO__LAST) {
+		ubifs_err(c, "superblock uses unknown hash algo %d",
+			  hash_algo);
+		return -EINVAL;
+	}
+
+	if (strcmp(hash_algo_name[hash_algo], c->auth_hash_name)) {
+		ubifs_err(c, "This filesystem uses %s for hashing,"
+			     " but %s is specified", hash_algo_name[hash_algo],
+			     c->auth_hash_name);
+		return -EINVAL;
+	}
+
+	/*
+	 * The super block node can either be authenticated by a HMAC or
+	 * by a signature in a ubifs_sig_node directly following the
+	 * super block node to support offline image creation.
+	 */
+	if (ubifs_hmac_zero(c, sup->hmac)) {
+		err = ubifs_sb_verify_signature(c, sup);
+	} else {
+		err = ubifs_hmac_wkm(c, hmac_wkm);
+		if (err)
+			return err;
+		if (ubifs_check_hmac(c, hmac_wkm, sup->hmac_wkm)) {
+			ubifs_err(c, "provided key does not fit");
+			return -ENOKEY;
+		}
+		err = ubifs_node_verify_hmac(c, sup, sizeof(*sup),
+					     offsetof(struct ubifs_sb_node,
+						      hmac));
+	}
+
+	if (err)
+		ubifs_err(c, "Failed to authenticate superblock: %d", err);
+
+	return err;
+}
+
+/**
+ * ubifs_write_sb_node - write superblock node.
+ * @c: UBIFS file-system description object
+ * @sup: superblock node read with 'ubifs_read_sb_node()'
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_write_sb_node(struct ubifs_info *c, struct ubifs_sb_node *sup)
+{
+	int len = ALIGN(UBIFS_SB_NODE_SZ, c->min_io_size);
+	int err;
+
+	err = ubifs_prepare_node_hmac(c, sup, UBIFS_SB_NODE_SZ,
+				      offsetof(struct ubifs_sb_node, hmac), 1);
+	if (err)
+		return err;
+
+	return ubifs_leb_change(c, UBIFS_SB_LNUM, sup, len);
+}
+
+/**
+ * ubifs_read_superblock - read superblock.
+ * @c: UBIFS file-system description object
+ *
+ * This function finds, reads and checks the superblock. If an empty UBI volume
+ * is being mounted, this function creates default superblock. Returns zero in
+ * case of success, and a negative error code in case of failure.
+ */
+int ubifs_read_superblock(struct ubifs_info *c)
+{
+	int err, sup_flags;
+	struct ubifs_sb_node *sup;
+
+	if (c->empty) {
+		err = create_default_filesystem(c);
+		if (err)
+			return err;
+	}
+
+	sup = ubifs_read_sb_node(c);
+	if (IS_ERR(sup))
+		return PTR_ERR(sup);
+
+	c->sup_node = sup;
+
+	c->fmt_version = le32_to_cpu(sup->fmt_version);
+	c->ro_compat_version = le32_to_cpu(sup->ro_compat_version);
+
+	/*
+	 * The software supports all previous versions but not future versions,
+	 * due to the unavailability of time-travelling equipment.
+	 */
+	if (c->fmt_version > UBIFS_FORMAT_VERSION) {
+		ubifs_assert(c, !c->ro_media || c->ro_mount);
+		if (!c->ro_mount ||
+		    c->ro_compat_version > UBIFS_RO_COMPAT_VERSION) {
+			ubifs_err(c, "on-flash format version is w%d/r%d, but software only supports up to version w%d/r%d",
+				  c->fmt_version, c->ro_compat_version,
+				  UBIFS_FORMAT_VERSION,
+				  UBIFS_RO_COMPAT_VERSION);
+			if (c->ro_compat_version <= UBIFS_RO_COMPAT_VERSION) {
+				ubifs_msg(c, "only R/O mounting is possible");
+				err = -EROFS;
+			} else
+				err = -EINVAL;
+			goto out;
+		}
+
+		/*
+		 * The FS is mounted R/O, and the media format is
+		 * R/O-compatible with the UBIFS implementation, so we can
+		 * mount.
+		 */
+		c->rw_incompat = 1;
+	}
+
+	if (c->fmt_version < 3) {
+		ubifs_err(c, "on-flash format version %d is not supported",
+			  c->fmt_version);
+		err = -EINVAL;
+		goto out;
+	}
+
+	switch (sup->key_hash) {
+	case UBIFS_KEY_HASH_R5:
+		c->key_hash = key_r5_hash;
+		c->key_hash_type = UBIFS_KEY_HASH_R5;
+		break;
+
+	case UBIFS_KEY_HASH_TEST:
+		c->key_hash = key_test_hash;
+		c->key_hash_type = UBIFS_KEY_HASH_TEST;
+		break;
+	}
+
+	c->key_fmt = sup->key_fmt;
+
+	switch (c->key_fmt) {
+	case UBIFS_SIMPLE_KEY_FMT:
+		c->key_len = UBIFS_SK_LEN;
+		break;
+	default:
+		ubifs_err(c, "unsupported key format");
+		err = -EINVAL;
+		goto out;
+	}
+
+	c->leb_cnt       = le32_to_cpu(sup->leb_cnt);
+	c->max_leb_cnt   = le32_to_cpu(sup->max_leb_cnt);
+	c->max_bud_bytes = le64_to_cpu(sup->max_bud_bytes);
+	c->log_lebs      = le32_to_cpu(sup->log_lebs);
+	c->lpt_lebs      = le32_to_cpu(sup->lpt_lebs);
+	c->orph_lebs     = le32_to_cpu(sup->orph_lebs);
+	c->jhead_cnt     = le32_to_cpu(sup->jhead_cnt) + NONDATA_JHEADS_CNT;
+	c->fanout        = le32_to_cpu(sup->fanout);
+	c->lsave_cnt     = le32_to_cpu(sup->lsave_cnt);
+	c->rp_size       = le64_to_cpu(sup->rp_size);
+	c->rp_uid        = make_kuid(&init_user_ns, le32_to_cpu(sup->rp_uid));
+	c->rp_gid        = make_kgid(&init_user_ns, le32_to_cpu(sup->rp_gid));
+	sup_flags        = le32_to_cpu(sup->flags);
+	if (!c->mount_opts.override_compr)
+		c->default_compr = le16_to_cpu(sup->default_compr);
+
+	c->vfs_sb->s_time_gran = le32_to_cpu(sup->time_gran);
+	memcpy(&c->uuid, &sup->uuid, 16);
+	c->big_lpt = !!(sup_flags & UBIFS_FLG_BIGLPT);
+	c->space_fixup = !!(sup_flags & UBIFS_FLG_SPACE_FIXUP);
+	c->double_hash = !!(sup_flags & UBIFS_FLG_DOUBLE_HASH);
+	c->encrypted = !!(sup_flags & UBIFS_FLG_ENCRYPTION);
+
+	err = authenticate_sb_node(c, sup);
+	if (err)
+		goto out;
+
+	if ((sup_flags & ~UBIFS_FLG_MASK) != 0) {
+		ubifs_err(c, "Unknown feature flags found: %#x",
+			  sup_flags & ~UBIFS_FLG_MASK);
+		err = -EINVAL;
+		goto out;
+	}
+
+	if (!IS_ENABLED(CONFIG_FS_ENCRYPTION) && c->encrypted) {
+		ubifs_err(c, "file system contains encrypted files but UBIFS"
+			     " was built without crypto support.");
+		err = -EINVAL;
+		goto out;
+	}
+
+	/* Automatically increase file system size to the maximum size */
+	if (c->leb_cnt < c->vi.size && c->leb_cnt < c->max_leb_cnt) {
+		int old_leb_cnt = c->leb_cnt;
+
+		c->leb_cnt = min_t(int, c->max_leb_cnt, c->vi.size);
+		sup->leb_cnt = cpu_to_le32(c->leb_cnt);
+
+		c->superblock_need_write = 1;
+
+		dbg_mnt("Auto resizing from %d LEBs to %d LEBs",
+			old_leb_cnt, c->leb_cnt);
+	}
+
+	c->log_bytes = (long long)c->log_lebs * c->leb_size;
+	c->log_last = UBIFS_LOG_LNUM + c->log_lebs - 1;
+	c->lpt_first = UBIFS_LOG_LNUM + c->log_lebs;
+	c->lpt_last = c->lpt_first + c->lpt_lebs - 1;
+	c->orph_first = c->lpt_last + 1;
+	c->orph_last = c->orph_first + c->orph_lebs - 1;
+	c->main_lebs = c->leb_cnt - UBIFS_SB_LEBS - UBIFS_MST_LEBS;
+	c->main_lebs -= c->log_lebs + c->lpt_lebs + c->orph_lebs;
+	c->main_first = c->leb_cnt - c->main_lebs;
+
+	err = validate_sb(c, sup);
+out:
+	return err;
+}
+
+/**
+ * fixup_leb - fixup/unmap an LEB containing free space.
+ * @c: UBIFS file-system description object
+ * @lnum: the LEB number to fix up
+ * @len: number of used bytes in LEB (starting at offset 0)
+ *
+ * This function reads the contents of the given LEB number @lnum, then fixes
+ * it up, so that empty min. I/O units in the end of LEB are actually erased on
+ * flash (rather than being just all-0xff real data). If the LEB is completely
+ * empty, it is simply unmapped.
+ */
+static int fixup_leb(struct ubifs_info *c, int lnum, int len)
+{
+	int err;
+
+	ubifs_assert(c, len >= 0);
+	ubifs_assert(c, len % c->min_io_size == 0);
+	ubifs_assert(c, len < c->leb_size);
+
+	if (len == 0) {
+		dbg_mnt("unmap empty LEB %d", lnum);
+		return ubifs_leb_unmap(c, lnum);
+	}
+
+	dbg_mnt("fixup LEB %d, data len %d", lnum, len);
+	err = ubifs_leb_read(c, lnum, c->sbuf, 0, len, 1);
+	if (err)
+		return err;
+
+	return ubifs_leb_change(c, lnum, c->sbuf, len);
+}
+
+/**
+ * fixup_free_space - find & remap all LEBs containing free space.
+ * @c: UBIFS file-system description object
+ *
+ * This function walks through all LEBs in the filesystem and fiexes up those
+ * containing free/empty space.
+ */
+static int fixup_free_space(struct ubifs_info *c)
+{
+	int lnum, err = 0;
+	struct ubifs_lprops *lprops;
+
+	ubifs_get_lprops(c);
+
+	/* Fixup LEBs in the master area */
+	for (lnum = UBIFS_MST_LNUM; lnum < UBIFS_LOG_LNUM; lnum++) {
+		err = fixup_leb(c, lnum, c->mst_offs + c->mst_node_alsz);
+		if (err)
+			goto out;
+	}
+
+	/* Unmap unused log LEBs */
+	lnum = ubifs_next_log_lnum(c, c->lhead_lnum);
+	while (lnum != c->ltail_lnum) {
+		err = fixup_leb(c, lnum, 0);
+		if (err)
+			goto out;
+		lnum = ubifs_next_log_lnum(c, lnum);
+	}
+
+	/*
+	 * Fixup the log head which contains the only a CS node at the
+	 * beginning.
+	 */
+	err = fixup_leb(c, c->lhead_lnum,
+			ALIGN(UBIFS_CS_NODE_SZ, c->min_io_size));
+	if (err)
+		goto out;
+
+	/* Fixup LEBs in the LPT area */
+	for (lnum = c->lpt_first; lnum <= c->lpt_last; lnum++) {
+		int free = c->ltab[lnum - c->lpt_first].free;
+
+		if (free > 0) {
+			err = fixup_leb(c, lnum, c->leb_size - free);
+			if (err)
+				goto out;
+		}
+	}
+
+	/* Unmap LEBs in the orphans area */
+	for (lnum = c->orph_first; lnum <= c->orph_last; lnum++) {
+		err = fixup_leb(c, lnum, 0);
+		if (err)
+			goto out;
+	}
+
+	/* Fixup LEBs in the main area */
+	for (lnum = c->main_first; lnum < c->leb_cnt; lnum++) {
+		lprops = ubifs_lpt_lookup(c, lnum);
+		if (IS_ERR(lprops)) {
+			err = PTR_ERR(lprops);
+			goto out;
+		}
+
+		if (lprops->free > 0) {
+			err = fixup_leb(c, lnum, c->leb_size - lprops->free);
+			if (err)
+				goto out;
+		}
+	}
+
+out:
+	ubifs_release_lprops(c);
+	return err;
+}
+
+/**
+ * ubifs_fixup_free_space - find & fix all LEBs with free space.
+ * @c: UBIFS file-system description object
+ *
+ * This function fixes up LEBs containing free space on first mount, if the
+ * appropriate flag was set when the FS was created. Each LEB with one or more
+ * empty min. I/O unit (i.e. free-space-count > 0) is re-written, to make sure
+ * the free space is actually erased. E.g., this is necessary for some NAND
+ * chips, since the free space may have been programmed like real "0xff" data
+ * (generating a non-0xff ECC), causing future writes to the not-really-erased
+ * NAND pages to behave badly. After the space is fixed up, the superblock flag
+ * is cleared, so that this is skipped for all future mounts.
+ */
+int ubifs_fixup_free_space(struct ubifs_info *c)
+{
+	int err;
+	struct ubifs_sb_node *sup = c->sup_node;
+
+	ubifs_assert(c, c->space_fixup);
+	ubifs_assert(c, !c->ro_mount);
+
+	ubifs_msg(c, "start fixing up free space");
+
+	err = fixup_free_space(c);
+	if (err)
+		return err;
+
+	/* Free-space fixup is no longer required */
+	c->space_fixup = 0;
+	sup->flags &= cpu_to_le32(~UBIFS_FLG_SPACE_FIXUP);
+
+	c->superblock_need_write = 1;
+
+	ubifs_msg(c, "free space fixup complete");
+	return err;
+}
+
+int ubifs_enable_encryption(struct ubifs_info *c)
+{
+	int err;
+	struct ubifs_sb_node *sup = c->sup_node;
+
+	if (!IS_ENABLED(CONFIG_FS_ENCRYPTION))
+		return -EOPNOTSUPP;
+
+	if (c->encrypted)
+		return 0;
+
+	if (c->ro_mount || c->ro_media)
+		return -EROFS;
+
+	if (c->fmt_version < 5) {
+		ubifs_err(c, "on-flash format version 5 is needed for encryption");
+		return -EINVAL;
+	}
+
+	sup->flags |= cpu_to_le32(UBIFS_FLG_ENCRYPTION);
+
+	err = ubifs_write_sb_node(c, sup);
+	if (!err)
+		c->encrypted = 1;
+
+	return err;
+}
diff --git a/ubifs-utils/libubifs/scan.c b/ubifs-utils/libubifs/scan.c
new file mode 100644
index 00000000..84a9157d
--- /dev/null
+++ b/ubifs-utils/libubifs/scan.c
@@ -0,0 +1,366 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file implements the scan which is a general-purpose function for
+ * determining what nodes are in an eraseblock. The scan is used to replay the
+ * journal, to do garbage collection. for the TNC in-the-gaps method, and by
+ * debugging functions.
+ */
+
+#include "ubifs.h"
+
+/**
+ * scan_padding_bytes - scan for padding bytes.
+ * @buf: buffer to scan
+ * @len: length of buffer
+ *
+ * This function returns the number of padding bytes on success and
+ * %SCANNED_GARBAGE on failure.
+ */
+static int scan_padding_bytes(void *buf, int len)
+{
+	int pad_len = 0, max_pad_len = min_t(int, UBIFS_PAD_NODE_SZ, len);
+	uint8_t *p = buf;
+
+	dbg_scan("not a node");
+
+	while (pad_len < max_pad_len && *p++ == UBIFS_PADDING_BYTE)
+		pad_len += 1;
+
+	if (!pad_len || (pad_len & 7))
+		return SCANNED_GARBAGE;
+
+	dbg_scan("%d padding bytes", pad_len);
+
+	return pad_len;
+}
+
+/**
+ * ubifs_scan_a_node - scan for a node or padding.
+ * @c: UBIFS file-system description object
+ * @buf: buffer to scan
+ * @len: length of buffer
+ * @lnum: logical eraseblock number
+ * @offs: offset within the logical eraseblock
+ * @quiet: print no messages
+ *
+ * This function returns a scanning code to indicate what was scanned.
+ */
+int ubifs_scan_a_node(const struct ubifs_info *c, void *buf, int len, int lnum,
+		      int offs, int quiet)
+{
+	struct ubifs_ch *ch = buf;
+	uint32_t magic;
+
+	magic = le32_to_cpu(ch->magic);
+
+	if (magic == 0xFFFFFFFF) {
+		dbg_scan("hit empty space at LEB %d:%d", lnum, offs);
+		return SCANNED_EMPTY_SPACE;
+	}
+
+	if (magic != UBIFS_NODE_MAGIC)
+		return scan_padding_bytes(buf, len);
+
+	if (len < UBIFS_CH_SZ)
+		return SCANNED_GARBAGE;
+
+	dbg_scan("scanning %s at LEB %d:%d",
+		 dbg_ntype(ch->node_type), lnum, offs);
+
+	if (ubifs_check_node(c, buf, len, lnum, offs, quiet, 1))
+		return SCANNED_A_CORRUPT_NODE;
+
+	if (ch->node_type == UBIFS_PAD_NODE) {
+		struct ubifs_pad_node *pad = buf;
+		int pad_len = le32_to_cpu(pad->pad_len);
+		int node_len = le32_to_cpu(ch->len);
+
+		/* Validate the padding node */
+		if (pad_len < 0 ||
+		    offs + node_len + pad_len > c->leb_size) {
+			if (!quiet) {
+				ubifs_err(c, "bad pad node at LEB %d:%d",
+					  lnum, offs);
+				ubifs_dump_node(c, pad, len);
+			}
+			return SCANNED_A_BAD_PAD_NODE;
+		}
+
+		/* Make the node pads to 8-byte boundary */
+		if ((node_len + pad_len) & 7) {
+			if (!quiet)
+				ubifs_err(c, "bad padding length %d - %d",
+					  offs, offs + node_len + pad_len);
+			return SCANNED_A_BAD_PAD_NODE;
+		}
+
+		dbg_scan("%d bytes padded at LEB %d:%d, offset now %d", pad_len,
+			 lnum, offs, ALIGN(offs + node_len + pad_len, 8));
+
+		return node_len + pad_len;
+	}
+
+	return SCANNED_A_NODE;
+}
+
+/**
+ * ubifs_start_scan - create LEB scanning information at start of scan.
+ * @c: UBIFS file-system description object
+ * @lnum: logical eraseblock number
+ * @offs: offset to start at (usually zero)
+ * @sbuf: scan buffer (must be c->leb_size)
+ *
+ * This function returns the scanned information on success and a negative error
+ * code on failure.
+ */
+struct ubifs_scan_leb *ubifs_start_scan(const struct ubifs_info *c, int lnum,
+					int offs, void *sbuf)
+{
+	struct ubifs_scan_leb *sleb;
+	int err;
+
+	dbg_scan("scan LEB %d:%d", lnum, offs);
+
+	sleb = kzalloc(sizeof(struct ubifs_scan_leb), GFP_NOFS);
+	if (!sleb)
+		return ERR_PTR(-ENOMEM);
+
+	sleb->lnum = lnum;
+	INIT_LIST_HEAD(&sleb->nodes);
+	sleb->buf = sbuf;
+
+	err = ubifs_leb_read(c, lnum, sbuf + offs, offs, c->leb_size - offs, 0);
+	if (err && err != -EBADMSG) {
+		ubifs_err(c, "cannot read %d bytes from LEB %d:%d, error %d",
+			  c->leb_size - offs, lnum, offs, err);
+		kfree(sleb);
+		return ERR_PTR(err);
+	}
+
+	/*
+	 * Note, we ignore integrity errors (EBASMSG) because all the nodes are
+	 * protected by CRC checksums.
+	 */
+	return sleb;
+}
+
+/**
+ * ubifs_end_scan - update LEB scanning information at end of scan.
+ * @c: UBIFS file-system description object
+ * @sleb: scanning information
+ * @lnum: logical eraseblock number
+ * @offs: offset to start at (usually zero)
+ */
+void ubifs_end_scan(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
+		    int lnum, int offs)
+{
+	dbg_scan("stop scanning LEB %d at offset %d", lnum, offs);
+	ubifs_assert(c, offs % c->min_io_size == 0);
+
+	sleb->endpt = ALIGN(offs, c->min_io_size);
+}
+
+/**
+ * ubifs_add_snod - add a scanned node to LEB scanning information.
+ * @c: UBIFS file-system description object
+ * @sleb: scanning information
+ * @buf: buffer containing node
+ * @offs: offset of node on flash
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+int ubifs_add_snod(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
+		   void *buf, int offs)
+{
+	struct ubifs_ch *ch = buf;
+	struct ubifs_ino_node *ino = buf;
+	struct ubifs_scan_node *snod;
+
+	snod = kmalloc(sizeof(struct ubifs_scan_node), GFP_NOFS);
+	if (!snod)
+		return -ENOMEM;
+
+	snod->sqnum = le64_to_cpu(ch->sqnum);
+	snod->type = ch->node_type;
+	snod->offs = offs;
+	snod->len = le32_to_cpu(ch->len);
+	snod->node = buf;
+
+	switch (ch->node_type) {
+	case UBIFS_INO_NODE:
+	case UBIFS_DENT_NODE:
+	case UBIFS_XENT_NODE:
+	case UBIFS_DATA_NODE:
+		/*
+		 * The key is in the same place in all keyed
+		 * nodes.
+		 */
+		key_read(c, &ino->key, &snod->key);
+		break;
+	default:
+		invalid_key_init(c, &snod->key);
+		break;
+	}
+	list_add_tail(&snod->list, &sleb->nodes);
+	sleb->nodes_cnt += 1;
+	return 0;
+}
+
+/**
+ * ubifs_scanned_corruption - print information after UBIFS scanned corruption.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number of corruption
+ * @offs: offset of corruption
+ * @buf: buffer containing corruption
+ */
+void ubifs_scanned_corruption(const struct ubifs_info *c, int lnum, int offs,
+			      void *buf)
+{
+	int len;
+
+	ubifs_err(c, "corruption at LEB %d:%d", lnum, offs);
+	len = c->leb_size - offs;
+	if (len > 8192)
+		len = 8192;
+	ubifs_err(c, "first %d bytes from LEB %d:%d", len, lnum, offs);
+	print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 4, buf, len, 1);
+}
+
+/**
+ * ubifs_scan - scan a logical eraseblock.
+ * @c: UBIFS file-system description object
+ * @lnum: logical eraseblock number
+ * @offs: offset to start at (usually zero)
+ * @sbuf: scan buffer (must be of @c->leb_size bytes in size)
+ * @quiet: print no messages
+ *
+ * This function scans LEB number @lnum and returns complete information about
+ * its contents. Returns the scanned information in case of success and,
+ * %-EUCLEAN if the LEB neads recovery, and other negative error codes in case
+ * of failure.
+ *
+ * If @quiet is non-zero, this function does not print large and scary
+ * error messages and flash dumps in case of errors.
+ */
+struct ubifs_scan_leb *ubifs_scan(const struct ubifs_info *c, int lnum,
+				  int offs, void *sbuf, int quiet)
+{
+	void *buf = sbuf + offs;
+	int err, len = c->leb_size - offs;
+	struct ubifs_scan_leb *sleb;
+
+	sleb = ubifs_start_scan(c, lnum, offs, sbuf);
+	if (IS_ERR(sleb))
+		return sleb;
+
+	while (len >= 8) {
+		struct ubifs_ch *ch = buf;
+		int node_len, ret;
+
+		dbg_scan("look at LEB %d:%d (%d bytes left)",
+			 lnum, offs, len);
+
+		cond_resched();
+
+		ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet);
+		if (ret > 0) {
+			/* Padding bytes or a valid padding node */
+			offs += ret;
+			buf += ret;
+			len -= ret;
+			continue;
+		}
+
+		if (ret == SCANNED_EMPTY_SPACE)
+			/* Empty space is checked later */
+			break;
+
+		switch (ret) {
+		case SCANNED_GARBAGE:
+			ubifs_err(c, "garbage");
+			goto corrupted;
+		case SCANNED_A_NODE:
+			break;
+		case SCANNED_A_CORRUPT_NODE:
+		case SCANNED_A_BAD_PAD_NODE:
+			ubifs_err(c, "bad node");
+			goto corrupted;
+		default:
+			ubifs_err(c, "unknown");
+			err = -EINVAL;
+			goto error;
+		}
+
+		err = ubifs_add_snod(c, sleb, buf, offs);
+		if (err)
+			goto error;
+
+		node_len = ALIGN(le32_to_cpu(ch->len), 8);
+		offs += node_len;
+		buf += node_len;
+		len -= node_len;
+	}
+
+	if (offs % c->min_io_size) {
+		if (!quiet)
+			ubifs_err(c, "empty space starts at non-aligned offset %d",
+				  offs);
+		goto corrupted;
+	}
+
+	ubifs_end_scan(c, sleb, lnum, offs);
+
+	for (; len > 4; offs += 4, buf = buf + 4, len -= 4)
+		if (*(uint32_t *)buf != 0xffffffff)
+			break;
+	for (; len; offs++, buf++, len--)
+		if (*(uint8_t *)buf != 0xff) {
+			if (!quiet)
+				ubifs_err(c, "corrupt empty space at LEB %d:%d",
+					  lnum, offs);
+			goto corrupted;
+		}
+
+	return sleb;
+
+corrupted:
+	if (!quiet) {
+		ubifs_scanned_corruption(c, lnum, offs, buf);
+		ubifs_err(c, "LEB %d scanning failed", lnum);
+	}
+	err = -EUCLEAN;
+	ubifs_scan_destroy(sleb);
+	return ERR_PTR(err);
+
+error:
+	ubifs_err(c, "LEB %d scanning failed, error %d", lnum, err);
+	ubifs_scan_destroy(sleb);
+	return ERR_PTR(err);
+}
+
+/**
+ * ubifs_scan_destroy - destroy LEB scanning information.
+ * @sleb: scanning information to free
+ */
+void ubifs_scan_destroy(struct ubifs_scan_leb *sleb)
+{
+	struct ubifs_scan_node *node;
+	struct list_head *head;
+
+	head = &sleb->nodes;
+	while (!list_empty(head)) {
+		node = list_entry(head->next, struct ubifs_scan_node, list);
+		list_del(&node->list);
+		kfree(node);
+	}
+	kfree(sleb);
+}
diff --git a/ubifs-utils/libubifs/super.c b/ubifs-utils/libubifs/super.c
new file mode 100644
index 00000000..09e270d6
--- /dev/null
+++ b/ubifs-utils/libubifs/super.c
@@ -0,0 +1,2505 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ */
+
+/*
+ * This file implements UBIFS initialization and VFS superblock operations. Some
+ * initialization stuff which is rather large and complex is placed at
+ * corresponding subsystems, but most of it is here.
+ */
+
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/ctype.h>
+#include <linux/kthread.h>
+#include <linux/parser.h>
+#include <linux/seq_file.h>
+#include <linux/mount.h>
+#include <linux/math64.h>
+#include <linux/writeback.h>
+#include "ubifs.h"
+
+static int ubifs_default_version_set(const char *val, const struct kernel_param *kp)
+{
+	int n = 0, ret;
+
+	ret = kstrtoint(val, 10, &n);
+	if (ret != 0 || n < 4 || n > UBIFS_FORMAT_VERSION)
+		return -EINVAL;
+	return param_set_int(val, kp);
+}
+
+static const struct kernel_param_ops ubifs_default_version_ops = {
+	.set = ubifs_default_version_set,
+	.get = param_get_int,
+};
+
+int ubifs_default_version = UBIFS_FORMAT_VERSION;
+module_param_cb(default_version, &ubifs_default_version_ops, &ubifs_default_version, 0600);
+
+/*
+ * Maximum amount of memory we may 'kmalloc()' without worrying that we are
+ * allocating too much.
+ */
+#define UBIFS_KMALLOC_OK (128*1024)
+
+/* Slab cache for UBIFS inodes */
+static struct kmem_cache *ubifs_inode_slab;
+
+/* UBIFS TNC shrinker description */
+static struct shrinker *ubifs_shrinker_info;
+
+/**
+ * validate_inode - validate inode.
+ * @c: UBIFS file-system description object
+ * @inode: the inode to validate
+ *
+ * This is a helper function for 'ubifs_iget()' which validates various fields
+ * of a newly built inode to make sure they contain sane values and prevent
+ * possible vulnerabilities. Returns zero if the inode is all right and
+ * a non-zero error code if not.
+ */
+static int validate_inode(struct ubifs_info *c, const struct inode *inode)
+{
+	int err;
+	const struct ubifs_inode *ui = ubifs_inode(inode);
+
+	if (inode->i_size > c->max_inode_sz) {
+		ubifs_err(c, "inode is too large (%lld)",
+			  (long long)inode->i_size);
+		return 1;
+	}
+
+	if (ui->compr_type >= UBIFS_COMPR_TYPES_CNT) {
+		ubifs_err(c, "unknown compression type %d", ui->compr_type);
+		return 2;
+	}
+
+	if (ui->xattr_names + ui->xattr_cnt > XATTR_LIST_MAX)
+		return 3;
+
+	if (ui->data_len < 0 || ui->data_len > UBIFS_MAX_INO_DATA)
+		return 4;
+
+	if (ui->xattr && !S_ISREG(inode->i_mode))
+		return 5;
+
+	if (!ubifs_compr_present(c, ui->compr_type)) {
+		ubifs_warn(c, "inode %lu uses '%s' compression, but it was not compiled in",
+			   inode->i_ino, ubifs_compr_name(c, ui->compr_type));
+	}
+
+	err = dbg_check_dir(c, inode);
+	return err;
+}
+
+struct inode *ubifs_iget(struct super_block *sb, unsigned long inum)
+{
+	int err;
+	union ubifs_key key;
+	struct ubifs_ino_node *ino;
+	struct ubifs_info *c = sb->s_fs_info;
+	struct inode *inode;
+	struct ubifs_inode *ui;
+
+	dbg_gen("inode %lu", inum);
+
+	inode = iget_locked(sb, inum);
+	if (!inode)
+		return ERR_PTR(-ENOMEM);
+	if (!(inode->i_state & I_NEW))
+		return inode;
+	ui = ubifs_inode(inode);
+
+	ino = kmalloc(UBIFS_MAX_INO_NODE_SZ, GFP_NOFS);
+	if (!ino) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	ino_key_init(c, &key, inode->i_ino);
+
+	err = ubifs_tnc_lookup(c, &key, ino);
+	if (err)
+		goto out_ino;
+
+	inode->i_flags |= S_NOCMTIME;
+
+	if (!IS_ENABLED(CONFIG_UBIFS_ATIME_SUPPORT))
+		inode->i_flags |= S_NOATIME;
+
+	set_nlink(inode, le32_to_cpu(ino->nlink));
+	i_uid_write(inode, le32_to_cpu(ino->uid));
+	i_gid_write(inode, le32_to_cpu(ino->gid));
+	inode_set_atime(inode, (int64_t)le64_to_cpu(ino->atime_sec),
+			le32_to_cpu(ino->atime_nsec));
+	inode_set_mtime(inode, (int64_t)le64_to_cpu(ino->mtime_sec),
+			le32_to_cpu(ino->mtime_nsec));
+	inode_set_ctime(inode, (int64_t)le64_to_cpu(ino->ctime_sec),
+			le32_to_cpu(ino->ctime_nsec));
+	inode->i_mode = le32_to_cpu(ino->mode);
+	inode->i_size = le64_to_cpu(ino->size);
+
+	ui->data_len    = le32_to_cpu(ino->data_len);
+	ui->flags       = le32_to_cpu(ino->flags);
+	ui->compr_type  = le16_to_cpu(ino->compr_type);
+	ui->creat_sqnum = le64_to_cpu(ino->creat_sqnum);
+	ui->xattr_cnt   = le32_to_cpu(ino->xattr_cnt);
+	ui->xattr_size  = le32_to_cpu(ino->xattr_size);
+	ui->xattr_names = le32_to_cpu(ino->xattr_names);
+	ui->synced_i_size = ui->ui_size = inode->i_size;
+
+	ui->xattr = (ui->flags & UBIFS_XATTR_FL) ? 1 : 0;
+
+	err = validate_inode(c, inode);
+	if (err)
+		goto out_invalid;
+
+	switch (inode->i_mode & S_IFMT) {
+	case S_IFREG:
+		inode->i_mapping->a_ops = &ubifs_file_address_operations;
+		inode->i_op = &ubifs_file_inode_operations;
+		inode->i_fop = &ubifs_file_operations;
+		if (ui->xattr) {
+			ui->data = kmalloc(ui->data_len + 1, GFP_NOFS);
+			if (!ui->data) {
+				err = -ENOMEM;
+				goto out_ino;
+			}
+			memcpy(ui->data, ino->data, ui->data_len);
+			((char *)ui->data)[ui->data_len] = '\0';
+		} else if (ui->data_len != 0) {
+			err = 10;
+			goto out_invalid;
+		}
+		break;
+	case S_IFDIR:
+		inode->i_op  = &ubifs_dir_inode_operations;
+		inode->i_fop = &ubifs_dir_operations;
+		if (ui->data_len != 0) {
+			err = 11;
+			goto out_invalid;
+		}
+		break;
+	case S_IFLNK:
+		inode->i_op = &ubifs_symlink_inode_operations;
+		if (ui->data_len <= 0 || ui->data_len > UBIFS_MAX_INO_DATA) {
+			err = 12;
+			goto out_invalid;
+		}
+		ui->data = kmalloc(ui->data_len + 1, GFP_NOFS);
+		if (!ui->data) {
+			err = -ENOMEM;
+			goto out_ino;
+		}
+		memcpy(ui->data, ino->data, ui->data_len);
+		((char *)ui->data)[ui->data_len] = '\0';
+		break;
+	case S_IFBLK:
+	case S_IFCHR:
+	{
+		dev_t rdev;
+		union ubifs_dev_desc *dev;
+
+		ui->data = kmalloc(sizeof(union ubifs_dev_desc), GFP_NOFS);
+		if (!ui->data) {
+			err = -ENOMEM;
+			goto out_ino;
+		}
+
+		dev = (union ubifs_dev_desc *)ino->data;
+		if (ui->data_len == sizeof(dev->new))
+			rdev = new_decode_dev(le32_to_cpu(dev->new));
+		else if (ui->data_len == sizeof(dev->huge))
+			rdev = huge_decode_dev(le64_to_cpu(dev->huge));
+		else {
+			err = 13;
+			goto out_invalid;
+		}
+		memcpy(ui->data, ino->data, ui->data_len);
+		inode->i_op = &ubifs_file_inode_operations;
+		init_special_inode(inode, inode->i_mode, rdev);
+		break;
+	}
+	case S_IFSOCK:
+	case S_IFIFO:
+		inode->i_op = &ubifs_file_inode_operations;
+		init_special_inode(inode, inode->i_mode, 0);
+		if (ui->data_len != 0) {
+			err = 14;
+			goto out_invalid;
+		}
+		break;
+	default:
+		err = 15;
+		goto out_invalid;
+	}
+
+	kfree(ino);
+	ubifs_set_inode_flags(inode);
+	unlock_new_inode(inode);
+	return inode;
+
+out_invalid:
+	ubifs_err(c, "inode %lu validation failed, error %d", inode->i_ino, err);
+	ubifs_dump_node(c, ino, UBIFS_MAX_INO_NODE_SZ);
+	ubifs_dump_inode(c, inode);
+	err = -EINVAL;
+out_ino:
+	kfree(ino);
+out:
+	ubifs_err(c, "failed to read inode %lu, error %d", inode->i_ino, err);
+	iget_failed(inode);
+	return ERR_PTR(err);
+}
+
+static struct inode *ubifs_alloc_inode(struct super_block *sb)
+{
+	struct ubifs_inode *ui;
+
+	ui = alloc_inode_sb(sb, ubifs_inode_slab, GFP_NOFS);
+	if (!ui)
+		return NULL;
+
+	memset((void *)ui + sizeof(struct inode), 0,
+	       sizeof(struct ubifs_inode) - sizeof(struct inode));
+	mutex_init(&ui->ui_mutex);
+	init_rwsem(&ui->xattr_sem);
+	spin_lock_init(&ui->ui_lock);
+	return &ui->vfs_inode;
+};
+
+static void ubifs_free_inode(struct inode *inode)
+{
+	struct ubifs_inode *ui = ubifs_inode(inode);
+
+	kfree(ui->data);
+	fscrypt_free_inode(inode);
+
+	kmem_cache_free(ubifs_inode_slab, ui);
+}
+
+/*
+ * Note, Linux write-back code calls this without 'i_mutex'.
+ */
+static int ubifs_write_inode(struct inode *inode, struct writeback_control *wbc)
+{
+	int err = 0;
+	struct ubifs_info *c = inode->i_sb->s_fs_info;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+
+	ubifs_assert(c, !ui->xattr);
+	if (is_bad_inode(inode))
+		return 0;
+
+	mutex_lock(&ui->ui_mutex);
+	/*
+	 * Due to races between write-back forced by budgeting
+	 * (see 'sync_some_inodes()') and background write-back, the inode may
+	 * have already been synchronized, do not do this again. This might
+	 * also happen if it was synchronized in an VFS operation, e.g.
+	 * 'ubifs_link()'.
+	 */
+	if (!ui->dirty) {
+		mutex_unlock(&ui->ui_mutex);
+		return 0;
+	}
+
+	/*
+	 * As an optimization, do not write orphan inodes to the media just
+	 * because this is not needed.
+	 */
+	dbg_gen("inode %lu, mode %#x, nlink %u",
+		inode->i_ino, (int)inode->i_mode, inode->i_nlink);
+	if (inode->i_nlink) {
+		err = ubifs_jnl_write_inode(c, inode);
+		if (err)
+			ubifs_err(c, "can't write inode %lu, error %d",
+				  inode->i_ino, err);
+		else
+			err = dbg_check_inode_size(c, inode, ui->ui_size);
+	}
+
+	ui->dirty = 0;
+	mutex_unlock(&ui->ui_mutex);
+	ubifs_release_dirty_inode_budget(c, ui);
+	return err;
+}
+
+static int ubifs_drop_inode(struct inode *inode)
+{
+	int drop = generic_drop_inode(inode);
+
+	if (!drop)
+		drop = fscrypt_drop_inode(inode);
+
+	return drop;
+}
+
+static void ubifs_evict_inode(struct inode *inode)
+{
+	int err;
+	struct ubifs_info *c = inode->i_sb->s_fs_info;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+
+	if (ui->xattr)
+		/*
+		 * Extended attribute inode deletions are fully handled in
+		 * 'ubifs_removexattr()'. These inodes are special and have
+		 * limited usage, so there is nothing to do here.
+		 */
+		goto out;
+
+	dbg_gen("inode %lu, mode %#x", inode->i_ino, (int)inode->i_mode);
+	ubifs_assert(c, !atomic_read(&inode->i_count));
+
+	truncate_inode_pages_final(&inode->i_data);
+
+	if (inode->i_nlink)
+		goto done;
+
+	if (is_bad_inode(inode))
+		goto out;
+
+	ui->ui_size = inode->i_size = 0;
+	err = ubifs_jnl_delete_inode(c, inode);
+	if (err)
+		/*
+		 * Worst case we have a lost orphan inode wasting space, so a
+		 * simple error message is OK here.
+		 */
+		ubifs_err(c, "can't delete inode %lu, error %d",
+			  inode->i_ino, err);
+
+out:
+	if (ui->dirty)
+		ubifs_release_dirty_inode_budget(c, ui);
+	else {
+		/* We've deleted something - clean the "no space" flags */
+		c->bi.nospace = c->bi.nospace_rp = 0;
+		smp_wmb();
+	}
+done:
+	clear_inode(inode);
+	fscrypt_put_encryption_info(inode);
+}
+
+static void ubifs_dirty_inode(struct inode *inode, int flags)
+{
+	struct ubifs_info *c = inode->i_sb->s_fs_info;
+	struct ubifs_inode *ui = ubifs_inode(inode);
+
+	ubifs_assert(c, mutex_is_locked(&ui->ui_mutex));
+	if (!ui->dirty) {
+		ui->dirty = 1;
+		dbg_gen("inode %lu",  inode->i_ino);
+	}
+}
+
+static int ubifs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+	struct ubifs_info *c = dentry->d_sb->s_fs_info;
+	unsigned long long free;
+	__le32 *uuid = (__le32 *)c->uuid;
+
+	free = ubifs_get_free_space(c);
+	dbg_gen("free space %lld bytes (%lld blocks)",
+		free, free >> UBIFS_BLOCK_SHIFT);
+
+	buf->f_type = UBIFS_SUPER_MAGIC;
+	buf->f_bsize = UBIFS_BLOCK_SIZE;
+	buf->f_blocks = c->block_cnt;
+	buf->f_bfree = free >> UBIFS_BLOCK_SHIFT;
+	if (free > c->report_rp_size)
+		buf->f_bavail = (free - c->report_rp_size) >> UBIFS_BLOCK_SHIFT;
+	else
+		buf->f_bavail = 0;
+	buf->f_files = 0;
+	buf->f_ffree = 0;
+	buf->f_namelen = UBIFS_MAX_NLEN;
+	buf->f_fsid.val[0] = le32_to_cpu(uuid[0]) ^ le32_to_cpu(uuid[2]);
+	buf->f_fsid.val[1] = le32_to_cpu(uuid[1]) ^ le32_to_cpu(uuid[3]);
+	ubifs_assert(c, buf->f_bfree <= c->block_cnt);
+	return 0;
+}
+
+static int ubifs_show_options(struct seq_file *s, struct dentry *root)
+{
+	struct ubifs_info *c = root->d_sb->s_fs_info;
+
+	if (c->mount_opts.unmount_mode == 2)
+		seq_puts(s, ",fast_unmount");
+	else if (c->mount_opts.unmount_mode == 1)
+		seq_puts(s, ",norm_unmount");
+
+	if (c->mount_opts.bulk_read == 2)
+		seq_puts(s, ",bulk_read");
+	else if (c->mount_opts.bulk_read == 1)
+		seq_puts(s, ",no_bulk_read");
+
+	if (c->mount_opts.chk_data_crc == 2)
+		seq_puts(s, ",chk_data_crc");
+	else if (c->mount_opts.chk_data_crc == 1)
+		seq_puts(s, ",no_chk_data_crc");
+
+	if (c->mount_opts.override_compr) {
+		seq_printf(s, ",compr=%s",
+			   ubifs_compr_name(c, c->mount_opts.compr_type));
+	}
+
+	seq_printf(s, ",assert=%s", ubifs_assert_action_name(c));
+	seq_printf(s, ",ubi=%d,vol=%d", c->vi.ubi_num, c->vi.vol_id);
+
+	return 0;
+}
+
+static int ubifs_sync_fs(struct super_block *sb, int wait)
+{
+	int i, err;
+	struct ubifs_info *c = sb->s_fs_info;
+
+	/*
+	 * Zero @wait is just an advisory thing to help the file system shove
+	 * lots of data into the queues, and there will be the second
+	 * '->sync_fs()' call, with non-zero @wait.
+	 */
+	if (!wait)
+		return 0;
+
+	/*
+	 * Synchronize write buffers, because 'ubifs_run_commit()' does not
+	 * do this if it waits for an already running commit.
+	 */
+	for (i = 0; i < c->jhead_cnt; i++) {
+		err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
+		if (err)
+			return err;
+	}
+
+	/*
+	 * Strictly speaking, it is not necessary to commit the journal here,
+	 * synchronizing write-buffers would be enough. But committing makes
+	 * UBIFS free space predictions much more accurate, so we want to let
+	 * the user be able to get more accurate results of 'statfs()' after
+	 * they synchronize the file system.
+	 */
+	err = ubifs_run_commit(c);
+	if (err)
+		return err;
+
+	return ubi_sync(c->vi.ubi_num);
+}
+
+/**
+ * init_constants_early - initialize UBIFS constants.
+ * @c: UBIFS file-system description object
+ *
+ * This function initialize UBIFS constants which do not need the superblock to
+ * be read. It also checks that the UBI volume satisfies basic UBIFS
+ * requirements. Returns zero in case of success and a negative error code in
+ * case of failure.
+ */
+static int init_constants_early(struct ubifs_info *c)
+{
+	if (c->vi.corrupted) {
+		ubifs_warn(c, "UBI volume is corrupted - read-only mode");
+		c->ro_media = 1;
+	}
+
+	if (c->di.ro_mode) {
+		ubifs_msg(c, "read-only UBI device");
+		c->ro_media = 1;
+	}
+
+	if (c->vi.vol_type == UBI_STATIC_VOLUME) {
+		ubifs_msg(c, "static UBI volume - read-only mode");
+		c->ro_media = 1;
+	}
+
+	c->leb_cnt = c->vi.size;
+	c->leb_size = c->vi.usable_leb_size;
+	c->leb_start = c->di.leb_start;
+	c->half_leb_size = c->leb_size / 2;
+	c->min_io_size = c->di.min_io_size;
+	c->min_io_shift = fls(c->min_io_size) - 1;
+	c->max_write_size = c->di.max_write_size;
+	c->max_write_shift = fls(c->max_write_size) - 1;
+
+	if (c->leb_size < UBIFS_MIN_LEB_SZ) {
+		ubifs_errc(c, "too small LEBs (%d bytes), min. is %d bytes",
+			   c->leb_size, UBIFS_MIN_LEB_SZ);
+		return -EINVAL;
+	}
+
+	if (c->leb_cnt < UBIFS_MIN_LEB_CNT) {
+		ubifs_errc(c, "too few LEBs (%d), min. is %d",
+			   c->leb_cnt, UBIFS_MIN_LEB_CNT);
+		return -EINVAL;
+	}
+
+	if (!is_power_of_2(c->min_io_size)) {
+		ubifs_errc(c, "bad min. I/O size %d", c->min_io_size);
+		return -EINVAL;
+	}
+
+	/*
+	 * Maximum write size has to be greater or equivalent to min. I/O
+	 * size, and be multiple of min. I/O size.
+	 */
+	if (c->max_write_size < c->min_io_size ||
+	    c->max_write_size % c->min_io_size ||
+	    !is_power_of_2(c->max_write_size)) {
+		ubifs_errc(c, "bad write buffer size %d for %d min. I/O unit",
+			   c->max_write_size, c->min_io_size);
+		return -EINVAL;
+	}
+
+	/*
+	 * UBIFS aligns all node to 8-byte boundary, so to make function in
+	 * io.c simpler, assume minimum I/O unit size to be 8 bytes if it is
+	 * less than 8.
+	 */
+	if (c->min_io_size < 8) {
+		c->min_io_size = 8;
+		c->min_io_shift = 3;
+		if (c->max_write_size < c->min_io_size) {
+			c->max_write_size = c->min_io_size;
+			c->max_write_shift = c->min_io_shift;
+		}
+	}
+
+	c->ref_node_alsz = ALIGN(UBIFS_REF_NODE_SZ, c->min_io_size);
+	c->mst_node_alsz = ALIGN(UBIFS_MST_NODE_SZ, c->min_io_size);
+
+	/*
+	 * Initialize node length ranges which are mostly needed for node
+	 * length validation.
+	 */
+	c->ranges[UBIFS_PAD_NODE].len  = UBIFS_PAD_NODE_SZ;
+	c->ranges[UBIFS_SB_NODE].len   = UBIFS_SB_NODE_SZ;
+	c->ranges[UBIFS_MST_NODE].len  = UBIFS_MST_NODE_SZ;
+	c->ranges[UBIFS_REF_NODE].len  = UBIFS_REF_NODE_SZ;
+	c->ranges[UBIFS_TRUN_NODE].len = UBIFS_TRUN_NODE_SZ;
+	c->ranges[UBIFS_CS_NODE].len   = UBIFS_CS_NODE_SZ;
+	c->ranges[UBIFS_AUTH_NODE].min_len = UBIFS_AUTH_NODE_SZ;
+	c->ranges[UBIFS_AUTH_NODE].max_len = UBIFS_AUTH_NODE_SZ +
+				UBIFS_MAX_HMAC_LEN;
+	c->ranges[UBIFS_SIG_NODE].min_len = UBIFS_SIG_NODE_SZ;
+	c->ranges[UBIFS_SIG_NODE].max_len = c->leb_size - UBIFS_SB_NODE_SZ;
+
+	c->ranges[UBIFS_INO_NODE].min_len  = UBIFS_INO_NODE_SZ;
+	c->ranges[UBIFS_INO_NODE].max_len  = UBIFS_MAX_INO_NODE_SZ;
+	c->ranges[UBIFS_ORPH_NODE].min_len =
+				UBIFS_ORPH_NODE_SZ + sizeof(__le64);
+	c->ranges[UBIFS_ORPH_NODE].max_len = c->leb_size;
+	c->ranges[UBIFS_DENT_NODE].min_len = UBIFS_DENT_NODE_SZ;
+	c->ranges[UBIFS_DENT_NODE].max_len = UBIFS_MAX_DENT_NODE_SZ;
+	c->ranges[UBIFS_XENT_NODE].min_len = UBIFS_XENT_NODE_SZ;
+	c->ranges[UBIFS_XENT_NODE].max_len = UBIFS_MAX_XENT_NODE_SZ;
+	c->ranges[UBIFS_DATA_NODE].min_len = UBIFS_DATA_NODE_SZ;
+	c->ranges[UBIFS_DATA_NODE].max_len = UBIFS_MAX_DATA_NODE_SZ;
+	/*
+	 * Minimum indexing node size is amended later when superblock is
+	 * read and the key length is known.
+	 */
+	c->ranges[UBIFS_IDX_NODE].min_len = UBIFS_IDX_NODE_SZ + UBIFS_BRANCH_SZ;
+	/*
+	 * Maximum indexing node size is amended later when superblock is
+	 * read and the fanout is known.
+	 */
+	c->ranges[UBIFS_IDX_NODE].max_len = INT_MAX;
+
+	/*
+	 * Initialize dead and dark LEB space watermarks. See gc.c for comments
+	 * about these values.
+	 */
+	c->dead_wm = ALIGN(MIN_WRITE_SZ, c->min_io_size);
+	c->dark_wm = ALIGN(UBIFS_MAX_NODE_SZ, c->min_io_size);
+
+	/*
+	 * Calculate how many bytes would be wasted at the end of LEB if it was
+	 * fully filled with data nodes of maximum size. This is used in
+	 * calculations when reporting free space.
+	 */
+	c->leb_overhead = c->leb_size % UBIFS_MAX_DATA_NODE_SZ;
+
+	/* Buffer size for bulk-reads */
+	c->max_bu_buf_len = UBIFS_MAX_BULK_READ * UBIFS_MAX_DATA_NODE_SZ;
+	if (c->max_bu_buf_len > c->leb_size)
+		c->max_bu_buf_len = c->leb_size;
+
+	/* Log is ready, preserve one LEB for commits. */
+	c->min_log_bytes = c->leb_size;
+
+	return 0;
+}
+
+/**
+ * bud_wbuf_callback - bud LEB write-buffer synchronization call-back.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB the write-buffer was synchronized to
+ * @free: how many free bytes left in this LEB
+ * @pad: how many bytes were padded
+ *
+ * This is a callback function which is called by the I/O unit when the
+ * write-buffer is synchronized. We need this to correctly maintain space
+ * accounting in bud logical eraseblocks. This function returns zero in case of
+ * success and a negative error code in case of failure.
+ *
+ * This function actually belongs to the journal, but we keep it here because
+ * we want to keep it static.
+ */
+static int bud_wbuf_callback(struct ubifs_info *c, int lnum, int free, int pad)
+{
+	return ubifs_update_one_lp(c, lnum, free, pad, 0, 0);
+}
+
+/*
+ * init_constants_sb - initialize UBIFS constants.
+ * @c: UBIFS file-system description object
+ *
+ * This is a helper function which initializes various UBIFS constants after
+ * the superblock has been read. It also checks various UBIFS parameters and
+ * makes sure they are all right. Returns zero in case of success and a
+ * negative error code in case of failure.
+ */
+static int init_constants_sb(struct ubifs_info *c)
+{
+	int tmp, err;
+	long long tmp64;
+
+	c->main_bytes = (long long)c->main_lebs * c->leb_size;
+	c->max_znode_sz = sizeof(struct ubifs_znode) +
+				c->fanout * sizeof(struct ubifs_zbranch);
+
+	tmp = ubifs_idx_node_sz(c, 1);
+	c->ranges[UBIFS_IDX_NODE].min_len = tmp;
+	c->min_idx_node_sz = ALIGN(tmp, 8);
+
+	tmp = ubifs_idx_node_sz(c, c->fanout);
+	c->ranges[UBIFS_IDX_NODE].max_len = tmp;
+	c->max_idx_node_sz = ALIGN(tmp, 8);
+
+	/* Make sure LEB size is large enough to fit full commit */
+	tmp = UBIFS_CS_NODE_SZ + UBIFS_REF_NODE_SZ * c->jhead_cnt;
+	tmp = ALIGN(tmp, c->min_io_size);
+	if (tmp > c->leb_size) {
+		ubifs_err(c, "too small LEB size %d, at least %d needed",
+			  c->leb_size, tmp);
+		return -EINVAL;
+	}
+
+	/*
+	 * Make sure that the log is large enough to fit reference nodes for
+	 * all buds plus one reserved LEB.
+	 */
+	tmp64 = c->max_bud_bytes + c->leb_size - 1;
+	c->max_bud_cnt = div_u64(tmp64, c->leb_size);
+	tmp = (c->ref_node_alsz * c->max_bud_cnt + c->leb_size - 1);
+	tmp /= c->leb_size;
+	tmp += 1;
+	if (c->log_lebs < tmp) {
+		ubifs_err(c, "too small log %d LEBs, required min. %d LEBs",
+			  c->log_lebs, tmp);
+		return -EINVAL;
+	}
+
+	/*
+	 * When budgeting we assume worst-case scenarios when the pages are not
+	 * be compressed and direntries are of the maximum size.
+	 *
+	 * Note, data, which may be stored in inodes is budgeted separately, so
+	 * it is not included into 'c->bi.inode_budget'.
+	 */
+	c->bi.page_budget = UBIFS_MAX_DATA_NODE_SZ * UBIFS_BLOCKS_PER_PAGE;
+	c->bi.inode_budget = UBIFS_INO_NODE_SZ;
+	c->bi.dent_budget = UBIFS_MAX_DENT_NODE_SZ;
+
+	/*
+	 * When the amount of flash space used by buds becomes
+	 * 'c->max_bud_bytes', UBIFS just blocks all writers and starts commit.
+	 * The writers are unblocked when the commit is finished. To avoid
+	 * writers to be blocked UBIFS initiates background commit in advance,
+	 * when number of bud bytes becomes above the limit defined below.
+	 */
+	c->bg_bud_bytes = (c->max_bud_bytes * 13) >> 4;
+
+	/*
+	 * Ensure minimum journal size. All the bytes in the journal heads are
+	 * considered to be used, when calculating the current journal usage.
+	 * Consequently, if the journal is too small, UBIFS will treat it as
+	 * always full.
+	 */
+	tmp64 = (long long)(c->jhead_cnt + 1) * c->leb_size + 1;
+	if (c->bg_bud_bytes < tmp64)
+		c->bg_bud_bytes = tmp64;
+	if (c->max_bud_bytes < tmp64 + c->leb_size)
+		c->max_bud_bytes = tmp64 + c->leb_size;
+
+	err = ubifs_calc_lpt_geom(c);
+	if (err)
+		return err;
+
+	/* Initialize effective LEB size used in budgeting calculations */
+	c->idx_leb_size = c->leb_size - c->max_idx_node_sz;
+	return 0;
+}
+
+/*
+ * init_constants_master - initialize UBIFS constants.
+ * @c: UBIFS file-system description object
+ *
+ * This is a helper function which initializes various UBIFS constants after
+ * the master node has been read. It also checks various UBIFS parameters and
+ * makes sure they are all right.
+ */
+static void init_constants_master(struct ubifs_info *c)
+{
+	long long tmp64;
+
+	c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
+	c->report_rp_size = ubifs_reported_space(c, c->rp_size);
+
+	/*
+	 * Calculate total amount of FS blocks. This number is not used
+	 * internally because it does not make much sense for UBIFS, but it is
+	 * necessary to report something for the 'statfs()' call.
+	 *
+	 * Subtract the LEB reserved for GC, the LEB which is reserved for
+	 * deletions, minimum LEBs for the index, and assume only one journal
+	 * head is available.
+	 */
+	tmp64 = c->main_lebs - 1 - 1 - MIN_INDEX_LEBS - c->jhead_cnt + 1;
+	tmp64 *= (long long)c->leb_size - c->leb_overhead;
+	tmp64 = ubifs_reported_space(c, tmp64);
+	c->block_cnt = tmp64 >> UBIFS_BLOCK_SHIFT;
+}
+
+/**
+ * take_gc_lnum - reserve GC LEB.
+ * @c: UBIFS file-system description object
+ *
+ * This function ensures that the LEB reserved for garbage collection is marked
+ * as "taken" in lprops. We also have to set free space to LEB size and dirty
+ * space to zero, because lprops may contain out-of-date information if the
+ * file-system was un-mounted before it has been committed. This function
+ * returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+static int take_gc_lnum(struct ubifs_info *c)
+{
+	int err;
+
+	if (c->gc_lnum == -1) {
+		ubifs_err(c, "no LEB for GC");
+		return -EINVAL;
+	}
+
+	/* And we have to tell lprops that this LEB is taken */
+	err = ubifs_change_one_lp(c, c->gc_lnum, c->leb_size, 0,
+				  LPROPS_TAKEN, 0, 0);
+	return err;
+}
+
+/**
+ * alloc_wbufs - allocate write-buffers.
+ * @c: UBIFS file-system description object
+ *
+ * This helper function allocates and initializes UBIFS write-buffers. Returns
+ * zero in case of success and %-ENOMEM in case of failure.
+ */
+static int alloc_wbufs(struct ubifs_info *c)
+{
+	int i, err;
+
+	c->jheads = kcalloc(c->jhead_cnt, sizeof(struct ubifs_jhead),
+			    GFP_KERNEL);
+	if (!c->jheads)
+		return -ENOMEM;
+
+	/* Initialize journal heads */
+	for (i = 0; i < c->jhead_cnt; i++) {
+		INIT_LIST_HEAD(&c->jheads[i].buds_list);
+		err = ubifs_wbuf_init(c, &c->jheads[i].wbuf);
+		if (err)
+			goto out_wbuf;
+
+		c->jheads[i].wbuf.sync_callback = &bud_wbuf_callback;
+		c->jheads[i].wbuf.jhead = i;
+		c->jheads[i].grouped = 1;
+		c->jheads[i].log_hash = ubifs_hash_get_desc(c);
+		if (IS_ERR(c->jheads[i].log_hash)) {
+			err = PTR_ERR(c->jheads[i].log_hash);
+			goto out_log_hash;
+		}
+	}
+
+	/*
+	 * Garbage Collector head does not need to be synchronized by timer.
+	 * Also GC head nodes are not grouped.
+	 */
+	c->jheads[GCHD].wbuf.no_timer = 1;
+	c->jheads[GCHD].grouped = 0;
+
+	return 0;
+
+out_log_hash:
+	kfree(c->jheads[i].wbuf.buf);
+	kfree(c->jheads[i].wbuf.inodes);
+
+out_wbuf:
+	while (i--) {
+		kfree(c->jheads[i].wbuf.buf);
+		kfree(c->jheads[i].wbuf.inodes);
+		kfree(c->jheads[i].log_hash);
+	}
+	kfree(c->jheads);
+	c->jheads = NULL;
+
+	return err;
+}
+
+/**
+ * free_wbufs - free write-buffers.
+ * @c: UBIFS file-system description object
+ */
+static void free_wbufs(struct ubifs_info *c)
+{
+	int i;
+
+	if (c->jheads) {
+		for (i = 0; i < c->jhead_cnt; i++) {
+			kfree(c->jheads[i].wbuf.buf);
+			kfree(c->jheads[i].wbuf.inodes);
+			kfree(c->jheads[i].log_hash);
+		}
+		kfree(c->jheads);
+		c->jheads = NULL;
+	}
+}
+
+/**
+ * free_orphans - free orphans.
+ * @c: UBIFS file-system description object
+ */
+static void free_orphans(struct ubifs_info *c)
+{
+	struct ubifs_orphan *orph;
+
+	while (c->orph_dnext) {
+		orph = c->orph_dnext;
+		c->orph_dnext = orph->dnext;
+		list_del(&orph->list);
+		kfree(orph);
+	}
+
+	while (!list_empty(&c->orph_list)) {
+		orph = list_entry(c->orph_list.next, struct ubifs_orphan, list);
+		list_del(&orph->list);
+		kfree(orph);
+		ubifs_err(c, "orphan list not empty at unmount");
+	}
+
+	vfree(c->orph_buf);
+	c->orph_buf = NULL;
+}
+
+/**
+ * free_buds - free per-bud objects.
+ * @c: UBIFS file-system description object
+ */
+static void free_buds(struct ubifs_info *c)
+{
+	struct ubifs_bud *bud, *n;
+
+	rbtree_postorder_for_each_entry_safe(bud, n, &c->buds, rb) {
+		kfree(bud->log_hash);
+		kfree(bud);
+	}
+}
+
+/**
+ * check_volume_empty - check if the UBI volume is empty.
+ * @c: UBIFS file-system description object
+ *
+ * This function checks if the UBIFS volume is empty by looking if its LEBs are
+ * mapped or not. The result of checking is stored in the @c->empty variable.
+ * Returns zero in case of success and a negative error code in case of
+ * failure.
+ */
+static int check_volume_empty(struct ubifs_info *c)
+{
+	int lnum, err;
+
+	c->empty = 1;
+	for (lnum = 0; lnum < c->leb_cnt; lnum++) {
+		err = ubifs_is_mapped(c, lnum);
+		if (unlikely(err < 0))
+			return err;
+		if (err == 1) {
+			c->empty = 0;
+			break;
+		}
+
+		cond_resched();
+	}
+
+	return 0;
+}
+
+/*
+ * UBIFS mount options.
+ *
+ * Opt_fast_unmount: do not run a journal commit before un-mounting
+ * Opt_norm_unmount: run a journal commit before un-mounting
+ * Opt_bulk_read: enable bulk-reads
+ * Opt_no_bulk_read: disable bulk-reads
+ * Opt_chk_data_crc: check CRCs when reading data nodes
+ * Opt_no_chk_data_crc: do not check CRCs when reading data nodes
+ * Opt_override_compr: override default compressor
+ * Opt_assert: set ubifs_assert() action
+ * Opt_auth_key: The key name used for authentication
+ * Opt_auth_hash_name: The hash type used for authentication
+ * Opt_err: just end of array marker
+ */
+enum {
+	Opt_fast_unmount,
+	Opt_norm_unmount,
+	Opt_bulk_read,
+	Opt_no_bulk_read,
+	Opt_chk_data_crc,
+	Opt_no_chk_data_crc,
+	Opt_override_compr,
+	Opt_assert,
+	Opt_auth_key,
+	Opt_auth_hash_name,
+	Opt_ignore,
+	Opt_err,
+};
+
+static const match_table_t tokens = {
+	{Opt_fast_unmount, "fast_unmount"},
+	{Opt_norm_unmount, "norm_unmount"},
+	{Opt_bulk_read, "bulk_read"},
+	{Opt_no_bulk_read, "no_bulk_read"},
+	{Opt_chk_data_crc, "chk_data_crc"},
+	{Opt_no_chk_data_crc, "no_chk_data_crc"},
+	{Opt_override_compr, "compr=%s"},
+	{Opt_auth_key, "auth_key=%s"},
+	{Opt_auth_hash_name, "auth_hash_name=%s"},
+	{Opt_ignore, "ubi=%s"},
+	{Opt_ignore, "vol=%s"},
+	{Opt_assert, "assert=%s"},
+	{Opt_err, NULL},
+};
+
+/**
+ * parse_standard_option - parse a standard mount option.
+ * @option: the option to parse
+ *
+ * Normally, standard mount options like "sync" are passed to file-systems as
+ * flags. However, when a "rootflags=" kernel boot parameter is used, they may
+ * be present in the options string. This function tries to deal with this
+ * situation and parse standard options. Returns 0 if the option was not
+ * recognized, and the corresponding integer flag if it was.
+ *
+ * UBIFS is only interested in the "sync" option, so do not check for anything
+ * else.
+ */
+static int parse_standard_option(const char *option)
+{
+
+	pr_notice("UBIFS: parse %s\n", option);
+	if (!strcmp(option, "sync"))
+		return SB_SYNCHRONOUS;
+	return 0;
+}
+
+/**
+ * ubifs_parse_options - parse mount parameters.
+ * @c: UBIFS file-system description object
+ * @options: parameters to parse
+ * @is_remount: non-zero if this is FS re-mount
+ *
+ * This function parses UBIFS mount options and returns zero in case success
+ * and a negative error code in case of failure.
+ */
+static int ubifs_parse_options(struct ubifs_info *c, char *options,
+			       int is_remount)
+{
+	char *p;
+	substring_t args[MAX_OPT_ARGS];
+
+	if (!options)
+		return 0;
+
+	while ((p = strsep(&options, ","))) {
+		int token;
+
+		if (!*p)
+			continue;
+
+		token = match_token(p, tokens, args);
+		switch (token) {
+		/*
+		 * %Opt_fast_unmount and %Opt_norm_unmount options are ignored.
+		 * We accept them in order to be backward-compatible. But this
+		 * should be removed at some point.
+		 */
+		case Opt_fast_unmount:
+			c->mount_opts.unmount_mode = 2;
+			break;
+		case Opt_norm_unmount:
+			c->mount_opts.unmount_mode = 1;
+			break;
+		case Opt_bulk_read:
+			c->mount_opts.bulk_read = 2;
+			c->bulk_read = 1;
+			break;
+		case Opt_no_bulk_read:
+			c->mount_opts.bulk_read = 1;
+			c->bulk_read = 0;
+			break;
+		case Opt_chk_data_crc:
+			c->mount_opts.chk_data_crc = 2;
+			c->no_chk_data_crc = 0;
+			break;
+		case Opt_no_chk_data_crc:
+			c->mount_opts.chk_data_crc = 1;
+			c->no_chk_data_crc = 1;
+			break;
+		case Opt_override_compr:
+		{
+			char *name = match_strdup(&args[0]);
+
+			if (!name)
+				return -ENOMEM;
+			if (!strcmp(name, "none"))
+				c->mount_opts.compr_type = UBIFS_COMPR_NONE;
+			else if (!strcmp(name, "lzo"))
+				c->mount_opts.compr_type = UBIFS_COMPR_LZO;
+			else if (!strcmp(name, "zlib"))
+				c->mount_opts.compr_type = UBIFS_COMPR_ZLIB;
+			else if (!strcmp(name, "zstd"))
+				c->mount_opts.compr_type = UBIFS_COMPR_ZSTD;
+			else {
+				ubifs_err(c, "unknown compressor \"%s\"", name); //FIXME: is c ready?
+				kfree(name);
+				return -EINVAL;
+			}
+			kfree(name);
+			c->mount_opts.override_compr = 1;
+			c->default_compr = c->mount_opts.compr_type;
+			break;
+		}
+		case Opt_assert:
+		{
+			char *act = match_strdup(&args[0]);
+
+			if (!act)
+				return -ENOMEM;
+			if (!strcmp(act, "report"))
+				c->assert_action = ASSACT_REPORT;
+			else if (!strcmp(act, "read-only"))
+				c->assert_action = ASSACT_RO;
+			else if (!strcmp(act, "panic"))
+				c->assert_action = ASSACT_PANIC;
+			else {
+				ubifs_err(c, "unknown assert action \"%s\"", act);
+				kfree(act);
+				return -EINVAL;
+			}
+			kfree(act);
+			break;
+		}
+		case Opt_auth_key:
+			if (!is_remount) {
+				c->auth_key_name = kstrdup(args[0].from,
+								GFP_KERNEL);
+				if (!c->auth_key_name)
+					return -ENOMEM;
+			}
+			break;
+		case Opt_auth_hash_name:
+			if (!is_remount) {
+				c->auth_hash_name = kstrdup(args[0].from,
+								GFP_KERNEL);
+				if (!c->auth_hash_name)
+					return -ENOMEM;
+			}
+			break;
+		case Opt_ignore:
+			break;
+		default:
+		{
+			unsigned long flag;
+			struct super_block *sb = c->vfs_sb;
+
+			flag = parse_standard_option(p);
+			if (!flag) {
+				ubifs_err(c, "unrecognized mount option \"%s\" or missing value",
+					  p);
+				return -EINVAL;
+			}
+			sb->s_flags |= flag;
+			break;
+		}
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * ubifs_release_options - release mount parameters which have been dumped.
+ * @c: UBIFS file-system description object
+ */
+static void ubifs_release_options(struct ubifs_info *c)
+{
+	kfree(c->auth_key_name);
+	c->auth_key_name = NULL;
+	kfree(c->auth_hash_name);
+	c->auth_hash_name = NULL;
+}
+
+/**
+ * destroy_journal - destroy journal data structures.
+ * @c: UBIFS file-system description object
+ *
+ * This function destroys journal data structures including those that may have
+ * been created by recovery functions.
+ */
+static void destroy_journal(struct ubifs_info *c)
+{
+	while (!list_empty(&c->unclean_leb_list)) {
+		struct ubifs_unclean_leb *ucleb;
+
+		ucleb = list_entry(c->unclean_leb_list.next,
+				   struct ubifs_unclean_leb, list);
+		list_del(&ucleb->list);
+		kfree(ucleb);
+	}
+	while (!list_empty(&c->old_buds)) {
+		struct ubifs_bud *bud;
+
+		bud = list_entry(c->old_buds.next, struct ubifs_bud, list);
+		list_del(&bud->list);
+		kfree(bud->log_hash);
+		kfree(bud);
+	}
+	ubifs_destroy_idx_gc(c);
+	ubifs_destroy_size_tree(c);
+	ubifs_tnc_close(c);
+	free_buds(c);
+}
+
+/**
+ * bu_init - initialize bulk-read information.
+ * @c: UBIFS file-system description object
+ */
+static void bu_init(struct ubifs_info *c)
+{
+	ubifs_assert(c, c->bulk_read == 1);
+
+	if (c->bu.buf)
+		return; /* Already initialized */
+
+again:
+	c->bu.buf = kmalloc(c->max_bu_buf_len, GFP_KERNEL | __GFP_NOWARN);
+	if (!c->bu.buf) {
+		if (c->max_bu_buf_len > UBIFS_KMALLOC_OK) {
+			c->max_bu_buf_len = UBIFS_KMALLOC_OK;
+			goto again;
+		}
+
+		/* Just disable bulk-read */
+		ubifs_warn(c, "cannot allocate %d bytes of memory for bulk-read, disabling it",
+			   c->max_bu_buf_len);
+		c->mount_opts.bulk_read = 1;
+		c->bulk_read = 0;
+		return;
+	}
+}
+
+/**
+ * check_free_space - check if there is enough free space to mount.
+ * @c: UBIFS file-system description object
+ *
+ * This function makes sure UBIFS has enough free space to be mounted in
+ * read/write mode. UBIFS must always have some free space to allow deletions.
+ */
+static int check_free_space(struct ubifs_info *c)
+{
+	ubifs_assert(c, c->dark_wm > 0);
+	if (c->lst.total_free + c->lst.total_dirty < c->dark_wm) {
+		ubifs_err(c, "insufficient free space to mount in R/W mode");
+		ubifs_dump_budg(c, &c->bi);
+		ubifs_dump_lprops(c);
+		return -ENOSPC;
+	}
+	return 0;
+}
+
+/**
+ * mount_ubifs - mount UBIFS file-system.
+ * @c: UBIFS file-system description object
+ *
+ * This function mounts UBIFS file system. Returns zero in case of success and
+ * a negative error code in case of failure.
+ */
+static int mount_ubifs(struct ubifs_info *c)
+{
+	int err;
+	long long x, y;
+	size_t sz;
+
+	c->ro_mount = !!sb_rdonly(c->vfs_sb);
+	/* Suppress error messages while probing if SB_SILENT is set */
+	c->probing = !!(c->vfs_sb->s_flags & SB_SILENT);
+
+	err = init_constants_early(c);
+	if (err)
+		return err;
+
+	err = ubifs_debugging_init(c);
+	if (err)
+		return err;
+
+	err = ubifs_sysfs_register(c);
+	if (err)
+		goto out_debugging;
+
+	err = check_volume_empty(c);
+	if (err)
+		goto out_free;
+
+	if (c->empty && (c->ro_mount || c->ro_media)) {
+		/*
+		 * This UBI volume is empty, and read-only, or the file system
+		 * is mounted read-only - we cannot format it.
+		 */
+		ubifs_err(c, "can't format empty UBI volume: read-only %s",
+			  c->ro_media ? "UBI volume" : "mount");
+		err = -EROFS;
+		goto out_free;
+	}
+
+	if (c->ro_media && !c->ro_mount) {
+		ubifs_err(c, "cannot mount read-write - read-only media");
+		err = -EROFS;
+		goto out_free;
+	}
+
+	/*
+	 * The requirement for the buffer is that it should fit indexing B-tree
+	 * height amount of integers. We assume the height if the TNC tree will
+	 * never exceed 64.
+	 */
+	err = -ENOMEM;
+	c->bottom_up_buf = kmalloc_array(BOTTOM_UP_HEIGHT, sizeof(int),
+					 GFP_KERNEL);
+	if (!c->bottom_up_buf)
+		goto out_free;
+
+	c->sbuf = vmalloc(c->leb_size);
+	if (!c->sbuf)
+		goto out_free;
+
+	if (!c->ro_mount) {
+		c->ileb_buf = vmalloc(c->leb_size);
+		if (!c->ileb_buf)
+			goto out_free;
+	}
+
+	if (c->bulk_read == 1)
+		bu_init(c);
+
+	if (!c->ro_mount) {
+		c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ + \
+					       UBIFS_CIPHER_BLOCK_SIZE,
+					       GFP_KERNEL);
+		if (!c->write_reserve_buf)
+			goto out_free;
+	}
+
+	c->mounting = 1;
+
+	if (c->auth_key_name) {
+		if (IS_ENABLED(CONFIG_UBIFS_FS_AUTHENTICATION)) {
+			err = ubifs_init_authentication(c);
+			if (err)
+				goto out_free;
+		} else {
+			ubifs_err(c, "auth_key_name, but UBIFS is built without"
+				  " authentication support");
+			err = -EINVAL;
+			goto out_free;
+		}
+	}
+
+	err = ubifs_read_superblock(c);
+	if (err)
+		goto out_auth;
+
+	c->probing = 0;
+
+	/*
+	 * Make sure the compressor which is set as default in the superblock
+	 * or overridden by mount options is actually compiled in.
+	 */
+	if (!ubifs_compr_present(c, c->default_compr)) {
+		ubifs_err(c, "'compressor \"%s\" is not compiled in",
+			  ubifs_compr_name(c, c->default_compr));
+		err = -ENOTSUPP;
+		goto out_auth;
+	}
+
+	err = init_constants_sb(c);
+	if (err)
+		goto out_auth;
+
+	sz = ALIGN(c->max_idx_node_sz, c->min_io_size) * 2;
+	c->cbuf = kmalloc(sz, GFP_NOFS);
+	if (!c->cbuf) {
+		err = -ENOMEM;
+		goto out_auth;
+	}
+
+	err = alloc_wbufs(c);
+	if (err)
+		goto out_cbuf;
+
+	sprintf(c->bgt_name, BGT_NAME_PATTERN, c->vi.ubi_num, c->vi.vol_id);
+	if (!c->ro_mount) {
+		/* Create background thread */
+		c->bgt = kthread_run(ubifs_bg_thread, c, "%s", c->bgt_name);
+		if (IS_ERR(c->bgt)) {
+			err = PTR_ERR(c->bgt);
+			c->bgt = NULL;
+			ubifs_err(c, "cannot spawn \"%s\", error %d",
+				  c->bgt_name, err);
+			goto out_wbufs;
+		}
+	}
+
+	err = ubifs_read_master(c);
+	if (err)
+		goto out_master;
+
+	init_constants_master(c);
+
+	if ((c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY)) != 0) {
+		ubifs_msg(c, "recovery needed");
+		c->need_recovery = 1;
+	}
+
+	if (c->need_recovery && !c->ro_mount) {
+		err = ubifs_recover_inl_heads(c, c->sbuf);
+		if (err)
+			goto out_master;
+	}
+
+	err = ubifs_lpt_init(c, 1, !c->ro_mount);
+	if (err)
+		goto out_master;
+
+	if (!c->ro_mount && c->space_fixup) {
+		err = ubifs_fixup_free_space(c);
+		if (err)
+			goto out_lpt;
+	}
+
+	if (!c->ro_mount && !c->need_recovery) {
+		/*
+		 * Set the "dirty" flag so that if we reboot uncleanly we
+		 * will notice this immediately on the next mount.
+		 */
+		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
+		err = ubifs_write_master(c);
+		if (err)
+			goto out_lpt;
+	}
+
+	/*
+	 * Handle offline signed images: Now that the master node is
+	 * written and its validation no longer depends on the hash
+	 * in the superblock, we can update the offline signed
+	 * superblock with a HMAC version,
+	 */
+	if (ubifs_authenticated(c) && ubifs_hmac_zero(c, c->sup_node->hmac)) {
+		err = ubifs_hmac_wkm(c, c->sup_node->hmac_wkm);
+		if (err)
+			goto out_lpt;
+		c->superblock_need_write = 1;
+	}
+
+	if (!c->ro_mount && c->superblock_need_write) {
+		err = ubifs_write_sb_node(c, c->sup_node);
+		if (err)
+			goto out_lpt;
+		c->superblock_need_write = 0;
+	}
+
+	err = dbg_check_idx_size(c, c->bi.old_idx_sz);
+	if (err)
+		goto out_lpt;
+
+	err = ubifs_replay_journal(c);
+	if (err)
+		goto out_journal;
+
+	/* Calculate 'min_idx_lebs' after journal replay */
+	c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
+
+	err = ubifs_mount_orphans(c, c->need_recovery, c->ro_mount);
+	if (err)
+		goto out_orphans;
+
+	if (!c->ro_mount) {
+		int lnum;
+
+		err = check_free_space(c);
+		if (err)
+			goto out_orphans;
+
+		/* Check for enough log space */
+		lnum = c->lhead_lnum + 1;
+		if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
+			lnum = UBIFS_LOG_LNUM;
+		if (lnum == c->ltail_lnum) {
+			err = ubifs_consolidate_log(c);
+			if (err)
+				goto out_orphans;
+		}
+
+		if (c->need_recovery) {
+			if (!ubifs_authenticated(c)) {
+				err = ubifs_recover_size(c, true);
+				if (err)
+					goto out_orphans;
+			}
+
+			err = ubifs_rcvry_gc_commit(c);
+			if (err)
+				goto out_orphans;
+
+			if (ubifs_authenticated(c)) {
+				err = ubifs_recover_size(c, false);
+				if (err)
+					goto out_orphans;
+			}
+		} else {
+			err = take_gc_lnum(c);
+			if (err)
+				goto out_orphans;
+
+			/*
+			 * GC LEB may contain garbage if there was an unclean
+			 * reboot, and it should be un-mapped.
+			 */
+			err = ubifs_leb_unmap(c, c->gc_lnum);
+			if (err)
+				goto out_orphans;
+		}
+
+		err = dbg_check_lprops(c);
+		if (err)
+			goto out_orphans;
+	} else if (c->need_recovery) {
+		err = ubifs_recover_size(c, false);
+		if (err)
+			goto out_orphans;
+	} else {
+		/*
+		 * Even if we mount read-only, we have to set space in GC LEB
+		 * to proper value because this affects UBIFS free space
+		 * reporting. We do not want to have a situation when
+		 * re-mounting from R/O to R/W changes amount of free space.
+		 */
+		err = take_gc_lnum(c);
+		if (err)
+			goto out_orphans;
+	}
+
+	spin_lock(&ubifs_infos_lock);
+	list_add_tail(&c->infos_list, &ubifs_infos);
+	spin_unlock(&ubifs_infos_lock);
+
+	if (c->need_recovery) {
+		if (c->ro_mount)
+			ubifs_msg(c, "recovery deferred");
+		else {
+			c->need_recovery = 0;
+			ubifs_msg(c, "recovery completed");
+			/*
+			 * GC LEB has to be empty and taken at this point. But
+			 * the journal head LEBs may also be accounted as
+			 * "empty taken" if they are empty.
+			 */
+			ubifs_assert(c, c->lst.taken_empty_lebs > 0);
+		}
+	} else
+		ubifs_assert(c, c->lst.taken_empty_lebs > 0);
+
+	err = dbg_check_filesystem(c);
+	if (err)
+		goto out_infos;
+
+	dbg_debugfs_init_fs(c);
+
+	c->mounting = 0;
+
+	ubifs_msg(c, "UBIFS: mounted UBI device %d, volume %d, name \"%s\"%s",
+		  c->vi.ubi_num, c->vi.vol_id, c->vi.name,
+		  c->ro_mount ? ", R/O mode" : "");
+	x = (long long)c->main_lebs * c->leb_size;
+	y = (long long)c->log_lebs * c->leb_size + c->max_bud_bytes;
+	ubifs_msg(c, "LEB size: %d bytes (%d KiB), min./max. I/O unit sizes: %d bytes/%d bytes",
+		  c->leb_size, c->leb_size >> 10, c->min_io_size,
+		  c->max_write_size);
+	ubifs_msg(c, "FS size: %lld bytes (%lld MiB, %d LEBs), max %d LEBs, journal size %lld bytes (%lld MiB, %d LEBs)",
+		  x, x >> 20, c->main_lebs, c->max_leb_cnt,
+		  y, y >> 20, c->log_lebs + c->max_bud_cnt);
+	ubifs_msg(c, "reserved for root: %llu bytes (%llu KiB)",
+		  c->report_rp_size, c->report_rp_size >> 10);
+	ubifs_msg(c, "media format: w%d/r%d (latest is w%d/r%d), UUID %pUB%s",
+		  c->fmt_version, c->ro_compat_version,
+		  UBIFS_FORMAT_VERSION, UBIFS_RO_COMPAT_VERSION, c->uuid,
+		  c->big_lpt ? ", big LPT model" : ", small LPT model");
+
+	dbg_gen("default compressor:  %s", ubifs_compr_name(c, c->default_compr));
+	dbg_gen("data journal heads:  %d",
+		c->jhead_cnt - NONDATA_JHEADS_CNT);
+	dbg_gen("log LEBs:            %d (%d - %d)",
+		c->log_lebs, UBIFS_LOG_LNUM, c->log_last);
+	dbg_gen("LPT area LEBs:       %d (%d - %d)",
+		c->lpt_lebs, c->lpt_first, c->lpt_last);
+	dbg_gen("orphan area LEBs:    %d (%d - %d)",
+		c->orph_lebs, c->orph_first, c->orph_last);
+	dbg_gen("main area LEBs:      %d (%d - %d)",
+		c->main_lebs, c->main_first, c->leb_cnt - 1);
+	dbg_gen("index LEBs:          %d", c->lst.idx_lebs);
+	dbg_gen("total index bytes:   %llu (%llu KiB, %llu MiB)",
+		c->bi.old_idx_sz, c->bi.old_idx_sz >> 10,
+		c->bi.old_idx_sz >> 20);
+	dbg_gen("key hash type:       %d", c->key_hash_type);
+	dbg_gen("tree fanout:         %d", c->fanout);
+	dbg_gen("reserved GC LEB:     %d", c->gc_lnum);
+	dbg_gen("max. znode size      %d", c->max_znode_sz);
+	dbg_gen("max. index node size %d", c->max_idx_node_sz);
+	dbg_gen("node sizes:          data %zu, inode %zu, dentry %zu",
+		UBIFS_DATA_NODE_SZ, UBIFS_INO_NODE_SZ, UBIFS_DENT_NODE_SZ);
+	dbg_gen("node sizes:          trun %zu, sb %zu, master %zu",
+		UBIFS_TRUN_NODE_SZ, UBIFS_SB_NODE_SZ, UBIFS_MST_NODE_SZ);
+	dbg_gen("node sizes:          ref %zu, cmt. start %zu, orph %zu",
+		UBIFS_REF_NODE_SZ, UBIFS_CS_NODE_SZ, UBIFS_ORPH_NODE_SZ);
+	dbg_gen("max. node sizes:     data %zu, inode %zu dentry %zu, idx %d",
+		UBIFS_MAX_DATA_NODE_SZ, UBIFS_MAX_INO_NODE_SZ,
+		UBIFS_MAX_DENT_NODE_SZ, ubifs_idx_node_sz(c, c->fanout));
+	dbg_gen("dead watermark:      %d", c->dead_wm);
+	dbg_gen("dark watermark:      %d", c->dark_wm);
+	dbg_gen("LEB overhead:        %d", c->leb_overhead);
+	x = (long long)c->main_lebs * c->dark_wm;
+	dbg_gen("max. dark space:     %lld (%lld KiB, %lld MiB)",
+		x, x >> 10, x >> 20);
+	dbg_gen("maximum bud bytes:   %lld (%lld KiB, %lld MiB)",
+		c->max_bud_bytes, c->max_bud_bytes >> 10,
+		c->max_bud_bytes >> 20);
+	dbg_gen("BG commit bud bytes: %lld (%lld KiB, %lld MiB)",
+		c->bg_bud_bytes, c->bg_bud_bytes >> 10,
+		c->bg_bud_bytes >> 20);
+	dbg_gen("current bud bytes    %lld (%lld KiB, %lld MiB)",
+		c->bud_bytes, c->bud_bytes >> 10, c->bud_bytes >> 20);
+	dbg_gen("max. seq. number:    %llu", c->max_sqnum);
+	dbg_gen("commit number:       %llu", c->cmt_no);
+	dbg_gen("max. xattrs per inode: %d", ubifs_xattr_max_cnt(c));
+	dbg_gen("max orphans:           %d", c->max_orphans);
+
+	return 0;
+
+out_infos:
+	spin_lock(&ubifs_infos_lock);
+	list_del(&c->infos_list);
+	spin_unlock(&ubifs_infos_lock);
+out_orphans:
+	free_orphans(c);
+out_journal:
+	destroy_journal(c);
+out_lpt:
+	ubifs_lpt_free(c, 0);
+out_master:
+	kfree(c->mst_node);
+	kfree(c->rcvrd_mst_node);
+	if (c->bgt)
+		kthread_stop(c->bgt);
+out_wbufs:
+	free_wbufs(c);
+out_cbuf:
+	kfree(c->cbuf);
+out_auth:
+	ubifs_exit_authentication(c);
+out_free:
+	kfree(c->write_reserve_buf);
+	kfree(c->bu.buf);
+	vfree(c->ileb_buf);
+	vfree(c->sbuf);
+	kfree(c->bottom_up_buf);
+	kfree(c->sup_node);
+	ubifs_sysfs_unregister(c);
+out_debugging:
+	ubifs_debugging_exit(c);
+	return err;
+}
+
+/**
+ * ubifs_umount - un-mount UBIFS file-system.
+ * @c: UBIFS file-system description object
+ *
+ * Note, this function is called to free allocated resourced when un-mounting,
+ * as well as free resources when an error occurred while we were half way
+ * through mounting (error path cleanup function). So it has to make sure the
+ * resource was actually allocated before freeing it.
+ */
+static void ubifs_umount(struct ubifs_info *c)
+{
+	dbg_gen("un-mounting UBI device %d, volume %d", c->vi.ubi_num,
+		c->vi.vol_id);
+
+	dbg_debugfs_exit_fs(c);
+	spin_lock(&ubifs_infos_lock);
+	list_del(&c->infos_list);
+	spin_unlock(&ubifs_infos_lock);
+
+	if (c->bgt)
+		kthread_stop(c->bgt);
+
+	destroy_journal(c);
+	free_wbufs(c);
+	free_orphans(c);
+	ubifs_lpt_free(c, 0);
+	ubifs_exit_authentication(c);
+
+	ubifs_release_options(c);
+	kfree(c->cbuf);
+	kfree(c->rcvrd_mst_node);
+	kfree(c->mst_node);
+	kfree(c->write_reserve_buf);
+	kfree(c->bu.buf);
+	vfree(c->ileb_buf);
+	vfree(c->sbuf);
+	kfree(c->bottom_up_buf);
+	kfree(c->sup_node);
+	ubifs_debugging_exit(c);
+	ubifs_sysfs_unregister(c);
+}
+
+/**
+ * ubifs_remount_rw - re-mount in read-write mode.
+ * @c: UBIFS file-system description object
+ *
+ * UBIFS avoids allocating many unnecessary resources when mounted in read-only
+ * mode. This function allocates the needed resources and re-mounts UBIFS in
+ * read-write mode.
+ */
+static int ubifs_remount_rw(struct ubifs_info *c)
+{
+	int err, lnum;
+
+	if (c->rw_incompat) {
+		ubifs_err(c, "the file-system is not R/W-compatible");
+		ubifs_msg(c, "on-flash format version is w%d/r%d, but software only supports up to version w%d/r%d",
+			  c->fmt_version, c->ro_compat_version,
+			  UBIFS_FORMAT_VERSION, UBIFS_RO_COMPAT_VERSION);
+		return -EROFS;
+	}
+
+	mutex_lock(&c->umount_mutex);
+	dbg_save_space_info(c);
+	c->remounting_rw = 1;
+	c->ro_mount = 0;
+
+	if (c->space_fixup) {
+		err = ubifs_fixup_free_space(c);
+		if (err)
+			goto out;
+	}
+
+	err = check_free_space(c);
+	if (err)
+		goto out;
+
+	if (c->need_recovery) {
+		ubifs_msg(c, "completing deferred recovery");
+		err = ubifs_write_rcvrd_mst_node(c);
+		if (err)
+			goto out;
+		if (!ubifs_authenticated(c)) {
+			err = ubifs_recover_size(c, true);
+			if (err)
+				goto out;
+		}
+		err = ubifs_clean_lebs(c, c->sbuf);
+		if (err)
+			goto out;
+		err = ubifs_recover_inl_heads(c, c->sbuf);
+		if (err)
+			goto out;
+	} else {
+		/* A readonly mount is not allowed to have orphans */
+		ubifs_assert(c, c->tot_orphans == 0);
+		err = ubifs_clear_orphans(c);
+		if (err)
+			goto out;
+	}
+
+	if (!(c->mst_node->flags & cpu_to_le32(UBIFS_MST_DIRTY))) {
+		c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
+		err = ubifs_write_master(c);
+		if (err)
+			goto out;
+	}
+
+	if (c->superblock_need_write) {
+		struct ubifs_sb_node *sup = c->sup_node;
+
+		err = ubifs_write_sb_node(c, sup);
+		if (err)
+			goto out;
+
+		c->superblock_need_write = 0;
+	}
+
+	c->ileb_buf = vmalloc(c->leb_size);
+	if (!c->ileb_buf) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	c->write_reserve_buf = kmalloc(COMPRESSED_DATA_NODE_BUF_SZ + \
+				       UBIFS_CIPHER_BLOCK_SIZE, GFP_KERNEL);
+	if (!c->write_reserve_buf) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	err = ubifs_lpt_init(c, 0, 1);
+	if (err)
+		goto out;
+
+	/* Create background thread */
+	c->bgt = kthread_run(ubifs_bg_thread, c, "%s", c->bgt_name);
+	if (IS_ERR(c->bgt)) {
+		err = PTR_ERR(c->bgt);
+		c->bgt = NULL;
+		ubifs_err(c, "cannot spawn \"%s\", error %d",
+			  c->bgt_name, err);
+		goto out;
+	}
+
+	c->orph_buf = vmalloc(c->leb_size);
+	if (!c->orph_buf) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	/* Check for enough log space */
+	lnum = c->lhead_lnum + 1;
+	if (lnum >= UBIFS_LOG_LNUM + c->log_lebs)
+		lnum = UBIFS_LOG_LNUM;
+	if (lnum == c->ltail_lnum) {
+		err = ubifs_consolidate_log(c);
+		if (err)
+			goto out;
+	}
+
+	if (c->need_recovery) {
+		err = ubifs_rcvry_gc_commit(c);
+		if (err)
+			goto out;
+
+		if (ubifs_authenticated(c)) {
+			err = ubifs_recover_size(c, false);
+			if (err)
+				goto out;
+		}
+	} else {
+		err = ubifs_leb_unmap(c, c->gc_lnum);
+	}
+	if (err)
+		goto out;
+
+	dbg_gen("re-mounted read-write");
+	c->remounting_rw = 0;
+
+	if (c->need_recovery) {
+		c->need_recovery = 0;
+		ubifs_msg(c, "deferred recovery completed");
+	} else {
+		/*
+		 * Do not run the debugging space check if the were doing
+		 * recovery, because when we saved the information we had the
+		 * file-system in a state where the TNC and lprops has been
+		 * modified in memory, but all the I/O operations (including a
+		 * commit) were deferred. So the file-system was in
+		 * "non-committed" state. Now the file-system is in committed
+		 * state, and of course the amount of free space will change
+		 * because, for example, the old index size was imprecise.
+		 */
+		err = dbg_check_space_info(c);
+	}
+
+	mutex_unlock(&c->umount_mutex);
+	return err;
+
+out:
+	c->ro_mount = 1;
+	vfree(c->orph_buf);
+	c->orph_buf = NULL;
+	if (c->bgt) {
+		kthread_stop(c->bgt);
+		c->bgt = NULL;
+	}
+	kfree(c->write_reserve_buf);
+	c->write_reserve_buf = NULL;
+	vfree(c->ileb_buf);
+	c->ileb_buf = NULL;
+	ubifs_lpt_free(c, 1);
+	c->remounting_rw = 0;
+	mutex_unlock(&c->umount_mutex);
+	return err;
+}
+
+/**
+ * ubifs_remount_ro - re-mount in read-only mode.
+ * @c: UBIFS file-system description object
+ *
+ * We assume VFS has stopped writing. Possibly the background thread could be
+ * running a commit, however kthread_stop will wait in that case.
+ */
+static void ubifs_remount_ro(struct ubifs_info *c)
+{
+	int i, err;
+
+	ubifs_assert(c, !c->need_recovery);
+	ubifs_assert(c, !c->ro_mount);
+
+	mutex_lock(&c->umount_mutex);
+	if (c->bgt) {
+		kthread_stop(c->bgt);
+		c->bgt = NULL;
+	}
+
+	dbg_save_space_info(c);
+
+	for (i = 0; i < c->jhead_cnt; i++) {
+		err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
+		if (err)
+			ubifs_ro_mode(c, err);
+	}
+
+	c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
+	c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
+	c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
+	err = ubifs_write_master(c);
+	if (err)
+		ubifs_ro_mode(c, err);
+
+	vfree(c->orph_buf);
+	c->orph_buf = NULL;
+	kfree(c->write_reserve_buf);
+	c->write_reserve_buf = NULL;
+	vfree(c->ileb_buf);
+	c->ileb_buf = NULL;
+	ubifs_lpt_free(c, 1);
+	c->ro_mount = 1;
+	err = dbg_check_space_info(c);
+	if (err)
+		ubifs_ro_mode(c, err);
+	mutex_unlock(&c->umount_mutex);
+}
+
+static void ubifs_put_super(struct super_block *sb)
+{
+	int i;
+	struct ubifs_info *c = sb->s_fs_info;
+
+	ubifs_msg(c, "un-mount UBI device %d", c->vi.ubi_num);
+
+	/*
+	 * The following asserts are only valid if there has not been a failure
+	 * of the media. For example, there will be dirty inodes if we failed
+	 * to write them back because of I/O errors.
+	 */
+	if (!c->ro_error) {
+		ubifs_assert(c, c->bi.idx_growth == 0);
+		ubifs_assert(c, c->bi.dd_growth == 0);
+		ubifs_assert(c, c->bi.data_growth == 0);
+	}
+
+	/*
+	 * The 'c->umount_lock' prevents races between UBIFS memory shrinker
+	 * and file system un-mount. Namely, it prevents the shrinker from
+	 * picking this superblock for shrinking - it will be just skipped if
+	 * the mutex is locked.
+	 */
+	mutex_lock(&c->umount_mutex);
+	if (!c->ro_mount) {
+		/*
+		 * First of all kill the background thread to make sure it does
+		 * not interfere with un-mounting and freeing resources.
+		 */
+		if (c->bgt) {
+			kthread_stop(c->bgt);
+			c->bgt = NULL;
+		}
+
+		/*
+		 * On fatal errors c->ro_error is set to 1, in which case we do
+		 * not write the master node.
+		 */
+		if (!c->ro_error) {
+			int err;
+
+			/* Synchronize write-buffers */
+			for (i = 0; i < c->jhead_cnt; i++) {
+				err = ubifs_wbuf_sync(&c->jheads[i].wbuf);
+				if (err)
+					ubifs_ro_mode(c, err);
+			}
+
+			/*
+			 * We are being cleanly unmounted which means the
+			 * orphans were killed - indicate this in the master
+			 * node. Also save the reserved GC LEB number.
+			 */
+			c->mst_node->flags &= ~cpu_to_le32(UBIFS_MST_DIRTY);
+			c->mst_node->flags |= cpu_to_le32(UBIFS_MST_NO_ORPHS);
+			c->mst_node->gc_lnum = cpu_to_le32(c->gc_lnum);
+			err = ubifs_write_master(c);
+			if (err)
+				/*
+				 * Recovery will attempt to fix the master area
+				 * next mount, so we just print a message and
+				 * continue to unmount normally.
+				 */
+				ubifs_err(c, "failed to write master node, error %d",
+					  err);
+		} else {
+			for (i = 0; i < c->jhead_cnt; i++)
+				/* Make sure write-buffer timers are canceled */
+				hrtimer_cancel(&c->jheads[i].wbuf.timer);
+		}
+	}
+
+	ubifs_umount(c);
+	ubi_close_volume(c->ubi);
+	mutex_unlock(&c->umount_mutex);
+}
+
+static int ubifs_remount_fs(struct super_block *sb, int *flags, char *data)
+{
+	int err;
+	struct ubifs_info *c = sb->s_fs_info;
+
+	sync_filesystem(sb);
+	dbg_gen("old flags %#lx, new flags %#x", sb->s_flags, *flags);
+
+	err = ubifs_parse_options(c, data, 1);
+	if (err) {
+		ubifs_err(c, "invalid or unknown remount parameter");
+		return err;
+	}
+
+	if (c->ro_mount && !(*flags & SB_RDONLY)) {
+		if (c->ro_error) {
+			ubifs_msg(c, "cannot re-mount R/W due to prior errors");
+			return -EROFS;
+		}
+		if (c->ro_media) {
+			ubifs_msg(c, "cannot re-mount R/W - UBI volume is R/O");
+			return -EROFS;
+		}
+		err = ubifs_remount_rw(c);
+		if (err)
+			return err;
+	} else if (!c->ro_mount && (*flags & SB_RDONLY)) {
+		if (c->ro_error) {
+			ubifs_msg(c, "cannot re-mount R/O due to prior errors");
+			return -EROFS;
+		}
+		ubifs_remount_ro(c);
+	}
+
+	if (c->bulk_read == 1)
+		bu_init(c);
+	else {
+		dbg_gen("disable bulk-read");
+		mutex_lock(&c->bu_mutex);
+		kfree(c->bu.buf);
+		c->bu.buf = NULL;
+		mutex_unlock(&c->bu_mutex);
+	}
+
+	if (!c->need_recovery)
+		ubifs_assert(c, c->lst.taken_empty_lebs > 0);
+
+	return 0;
+}
+
+const struct super_operations ubifs_super_operations = {
+	.alloc_inode   = ubifs_alloc_inode,
+	.free_inode    = ubifs_free_inode,
+	.put_super     = ubifs_put_super,
+	.write_inode   = ubifs_write_inode,
+	.drop_inode    = ubifs_drop_inode,
+	.evict_inode   = ubifs_evict_inode,
+	.statfs        = ubifs_statfs,
+	.dirty_inode   = ubifs_dirty_inode,
+	.remount_fs    = ubifs_remount_fs,
+	.show_options  = ubifs_show_options,
+	.sync_fs       = ubifs_sync_fs,
+};
+
+/**
+ * open_ubi - parse UBI device name string and open the UBI device.
+ * @name: UBI volume name
+ * @mode: UBI volume open mode
+ *
+ * The primary method of mounting UBIFS is by specifying the UBI volume
+ * character device node path. However, UBIFS may also be mounted without any
+ * character device node using one of the following methods:
+ *
+ * o ubiX_Y    - mount UBI device number X, volume Y;
+ * o ubiY      - mount UBI device number 0, volume Y;
+ * o ubiX:NAME - mount UBI device X, volume with name NAME;
+ * o ubi:NAME  - mount UBI device 0, volume with name NAME.
+ *
+ * Alternative '!' separator may be used instead of ':' (because some shells
+ * like busybox may interpret ':' as an NFS host name separator). This function
+ * returns UBI volume description object in case of success and a negative
+ * error code in case of failure.
+ */
+static struct ubi_volume_desc *open_ubi(const char *name, int mode)
+{
+	struct ubi_volume_desc *ubi;
+	int dev, vol;
+	char *endptr;
+
+	if (!name || !*name)
+		return ERR_PTR(-EINVAL);
+
+	/* First, try to open using the device node path method */
+	ubi = ubi_open_volume_path(name, mode);
+	if (!IS_ERR(ubi))
+		return ubi;
+
+	/* Try the "nodev" method */
+	if (name[0] != 'u' || name[1] != 'b' || name[2] != 'i')
+		return ERR_PTR(-EINVAL);
+
+	/* ubi:NAME method */
+	if ((name[3] == ':' || name[3] == '!') && name[4] != '\0')
+		return ubi_open_volume_nm(0, name + 4, mode);
+
+	if (!isdigit(name[3]))
+		return ERR_PTR(-EINVAL);
+
+	dev = simple_strtoul(name + 3, &endptr, 0);
+
+	/* ubiY method */
+	if (*endptr == '\0')
+		return ubi_open_volume(0, dev, mode);
+
+	/* ubiX_Y method */
+	if (*endptr == '_' && isdigit(endptr[1])) {
+		vol = simple_strtoul(endptr + 1, &endptr, 0);
+		if (*endptr != '\0')
+			return ERR_PTR(-EINVAL);
+		return ubi_open_volume(dev, vol, mode);
+	}
+
+	/* ubiX:NAME method */
+	if ((*endptr == ':' || *endptr == '!') && endptr[1] != '\0')
+		return ubi_open_volume_nm(dev, ++endptr, mode);
+
+	return ERR_PTR(-EINVAL);
+}
+
+static struct ubifs_info *alloc_ubifs_info(struct ubi_volume_desc *ubi)
+{
+	struct ubifs_info *c;
+
+	c = kzalloc(sizeof(struct ubifs_info), GFP_KERNEL);
+	if (c) {
+		spin_lock_init(&c->cnt_lock);
+		spin_lock_init(&c->cs_lock);
+		spin_lock_init(&c->buds_lock);
+		spin_lock_init(&c->space_lock);
+		spin_lock_init(&c->orphan_lock);
+		init_rwsem(&c->commit_sem);
+		mutex_init(&c->lp_mutex);
+		mutex_init(&c->tnc_mutex);
+		mutex_init(&c->log_mutex);
+		mutex_init(&c->umount_mutex);
+		mutex_init(&c->bu_mutex);
+		mutex_init(&c->write_reserve_mutex);
+		init_waitqueue_head(&c->cmt_wq);
+		c->buds = RB_ROOT;
+		c->old_idx = RB_ROOT;
+		c->size_tree = RB_ROOT;
+		c->orph_tree = RB_ROOT;
+		INIT_LIST_HEAD(&c->infos_list);
+		INIT_LIST_HEAD(&c->idx_gc);
+		INIT_LIST_HEAD(&c->replay_list);
+		INIT_LIST_HEAD(&c->replay_buds);
+		INIT_LIST_HEAD(&c->uncat_list);
+		INIT_LIST_HEAD(&c->empty_list);
+		INIT_LIST_HEAD(&c->freeable_list);
+		INIT_LIST_HEAD(&c->frdi_idx_list);
+		INIT_LIST_HEAD(&c->unclean_leb_list);
+		INIT_LIST_HEAD(&c->old_buds);
+		INIT_LIST_HEAD(&c->orph_list);
+		INIT_LIST_HEAD(&c->orph_new);
+		c->no_chk_data_crc = 1;
+		c->assert_action = ASSACT_RO;
+
+		c->highest_inum = UBIFS_FIRST_INO;
+		c->lhead_lnum = c->ltail_lnum = UBIFS_LOG_LNUM;
+
+		ubi_get_volume_info(ubi, &c->vi);
+		ubi_get_device_info(c->vi.ubi_num, &c->di);
+	}
+	return c;
+}
+
+static int ubifs_fill_super(struct super_block *sb, void *data, int silent)
+{
+	struct ubifs_info *c = sb->s_fs_info;
+	struct inode *root;
+	int err;
+
+	c->vfs_sb = sb;
+	/* Re-open the UBI device in read-write mode */
+	c->ubi = ubi_open_volume(c->vi.ubi_num, c->vi.vol_id, UBI_READWRITE);
+	if (IS_ERR(c->ubi)) {
+		err = PTR_ERR(c->ubi);
+		goto out;
+	}
+
+	err = ubifs_parse_options(c, data, 0);
+	if (err)
+		goto out_close;
+
+	/*
+	 * UBIFS provides 'backing_dev_info' in order to disable read-ahead. For
+	 * UBIFS, I/O is not deferred, it is done immediately in read_folio,
+	 * which means the user would have to wait not just for their own I/O
+	 * but the read-ahead I/O as well i.e. completely pointless.
+	 *
+	 * Read-ahead will be disabled because @sb->s_bdi->ra_pages is 0. Also
+	 * @sb->s_bdi->capabilities are initialized to 0 so there won't be any
+	 * writeback happening.
+	 */
+	err = super_setup_bdi_name(sb, "ubifs_%d_%d", c->vi.ubi_num,
+				   c->vi.vol_id);
+	if (err)
+		goto out_close;
+	sb->s_bdi->ra_pages = 0;
+	sb->s_bdi->io_pages = 0;
+
+	sb->s_fs_info = c;
+	sb->s_magic = UBIFS_SUPER_MAGIC;
+	sb->s_blocksize = UBIFS_BLOCK_SIZE;
+	sb->s_blocksize_bits = UBIFS_BLOCK_SHIFT;
+	sb->s_maxbytes = c->max_inode_sz = key_max_inode_size(c);
+	if (c->max_inode_sz > MAX_LFS_FILESIZE)
+		sb->s_maxbytes = c->max_inode_sz = MAX_LFS_FILESIZE;
+	sb->s_op = &ubifs_super_operations;
+	sb->s_xattr = ubifs_xattr_handlers;
+	fscrypt_set_ops(sb, &ubifs_crypt_operations);
+
+	mutex_lock(&c->umount_mutex);
+	err = mount_ubifs(c);
+	if (err) {
+		ubifs_assert(c, err < 0);
+		goto out_unlock;
+	}
+
+	/* Read the root inode */
+	root = ubifs_iget(sb, UBIFS_ROOT_INO);
+	if (IS_ERR(root)) {
+		err = PTR_ERR(root);
+		goto out_umount;
+	}
+
+	sb->s_root = d_make_root(root);
+	if (!sb->s_root) {
+		err = -ENOMEM;
+		goto out_umount;
+	}
+
+	import_uuid(&sb->s_uuid, c->uuid);
+
+	mutex_unlock(&c->umount_mutex);
+	return 0;
+
+out_umount:
+	ubifs_umount(c);
+out_unlock:
+	mutex_unlock(&c->umount_mutex);
+out_close:
+	ubifs_release_options(c);
+	ubi_close_volume(c->ubi);
+out:
+	return err;
+}
+
+static int sb_test(struct super_block *sb, void *data)
+{
+	struct ubifs_info *c1 = data;
+	struct ubifs_info *c = sb->s_fs_info;
+
+	return c->vi.cdev == c1->vi.cdev;
+}
+
+static int sb_set(struct super_block *sb, void *data)
+{
+	sb->s_fs_info = data;
+	return set_anon_super(sb, NULL);
+}
+
+static struct dentry *ubifs_mount(struct file_system_type *fs_type, int flags,
+			const char *name, void *data)
+{
+	struct ubi_volume_desc *ubi;
+	struct ubifs_info *c;
+	struct super_block *sb;
+	int err;
+
+	dbg_gen("name %s, flags %#x", name, flags);
+
+	/*
+	 * Get UBI device number and volume ID. Mount it read-only so far
+	 * because this might be a new mount point, and UBI allows only one
+	 * read-write user at a time.
+	 */
+	ubi = open_ubi(name, UBI_READONLY);
+	if (IS_ERR(ubi)) {
+		if (!(flags & SB_SILENT))
+			pr_err("UBIFS error (pid: %d): cannot open \"%s\", error %d",
+			       current->pid, name, (int)PTR_ERR(ubi));
+		return ERR_CAST(ubi);
+	}
+
+	c = alloc_ubifs_info(ubi);
+	if (!c) {
+		err = -ENOMEM;
+		goto out_close;
+	}
+
+	dbg_gen("opened ubi%d_%d", c->vi.ubi_num, c->vi.vol_id);
+
+	sb = sget(fs_type, sb_test, sb_set, flags, c);
+	if (IS_ERR(sb)) {
+		err = PTR_ERR(sb);
+		kfree(c);
+		goto out_close;
+	}
+
+	if (sb->s_root) {
+		struct ubifs_info *c1 = sb->s_fs_info;
+		kfree(c);
+		/* A new mount point for already mounted UBIFS */
+		dbg_gen("this ubi volume is already mounted");
+		if (!!(flags & SB_RDONLY) != c1->ro_mount) {
+			err = -EBUSY;
+			goto out_deact;
+		}
+	} else {
+		err = ubifs_fill_super(sb, data, flags & SB_SILENT ? 1 : 0);
+		if (err)
+			goto out_deact;
+		/* We do not support atime */
+		sb->s_flags |= SB_ACTIVE;
+		if (IS_ENABLED(CONFIG_UBIFS_ATIME_SUPPORT))
+			ubifs_msg(c, "full atime support is enabled.");
+		else
+			sb->s_flags |= SB_NOATIME;
+	}
+
+	/* 'fill_super()' opens ubi again so we must close it here */
+	ubi_close_volume(ubi);
+
+	return dget(sb->s_root);
+
+out_deact:
+	deactivate_locked_super(sb);
+out_close:
+	ubi_close_volume(ubi);
+	return ERR_PTR(err);
+}
+
+static void kill_ubifs_super(struct super_block *s)
+{
+	struct ubifs_info *c = s->s_fs_info;
+	kill_anon_super(s);
+	kfree(c);
+}
+
+static struct file_system_type ubifs_fs_type = {
+	.name    = "ubifs",
+	.owner   = THIS_MODULE,
+	.mount   = ubifs_mount,
+	.kill_sb = kill_ubifs_super,
+};
+MODULE_ALIAS_FS("ubifs");
+
+/*
+ * Inode slab cache constructor.
+ */
+static void inode_slab_ctor(void *obj)
+{
+	struct ubifs_inode *ui = obj;
+	inode_init_once(&ui->vfs_inode);
+}
+
+static int __init ubifs_init(void)
+{
+	int err = -ENOMEM;
+
+	BUILD_BUG_ON(sizeof(struct ubifs_ch) != 24);
+
+	/* Make sure node sizes are 8-byte aligned */
+	BUILD_BUG_ON(UBIFS_CH_SZ        & 7);
+	BUILD_BUG_ON(UBIFS_INO_NODE_SZ  & 7);
+	BUILD_BUG_ON(UBIFS_DENT_NODE_SZ & 7);
+	BUILD_BUG_ON(UBIFS_XENT_NODE_SZ & 7);
+	BUILD_BUG_ON(UBIFS_DATA_NODE_SZ & 7);
+	BUILD_BUG_ON(UBIFS_TRUN_NODE_SZ & 7);
+	BUILD_BUG_ON(UBIFS_SB_NODE_SZ   & 7);
+	BUILD_BUG_ON(UBIFS_MST_NODE_SZ  & 7);
+	BUILD_BUG_ON(UBIFS_REF_NODE_SZ  & 7);
+	BUILD_BUG_ON(UBIFS_CS_NODE_SZ   & 7);
+	BUILD_BUG_ON(UBIFS_ORPH_NODE_SZ & 7);
+
+	BUILD_BUG_ON(UBIFS_MAX_DENT_NODE_SZ & 7);
+	BUILD_BUG_ON(UBIFS_MAX_XENT_NODE_SZ & 7);
+	BUILD_BUG_ON(UBIFS_MAX_DATA_NODE_SZ & 7);
+	BUILD_BUG_ON(UBIFS_MAX_INO_NODE_SZ  & 7);
+	BUILD_BUG_ON(UBIFS_MAX_NODE_SZ      & 7);
+	BUILD_BUG_ON(MIN_WRITE_SZ           & 7);
+
+	/* Check min. node size */
+	BUILD_BUG_ON(UBIFS_INO_NODE_SZ  < MIN_WRITE_SZ);
+	BUILD_BUG_ON(UBIFS_DENT_NODE_SZ < MIN_WRITE_SZ);
+	BUILD_BUG_ON(UBIFS_XENT_NODE_SZ < MIN_WRITE_SZ);
+	BUILD_BUG_ON(UBIFS_TRUN_NODE_SZ < MIN_WRITE_SZ);
+
+	BUILD_BUG_ON(UBIFS_MAX_DENT_NODE_SZ > UBIFS_MAX_NODE_SZ);
+	BUILD_BUG_ON(UBIFS_MAX_XENT_NODE_SZ > UBIFS_MAX_NODE_SZ);
+	BUILD_BUG_ON(UBIFS_MAX_DATA_NODE_SZ > UBIFS_MAX_NODE_SZ);
+	BUILD_BUG_ON(UBIFS_MAX_INO_NODE_SZ  > UBIFS_MAX_NODE_SZ);
+
+	/* Defined node sizes */
+	BUILD_BUG_ON(UBIFS_SB_NODE_SZ  != 4096);
+	BUILD_BUG_ON(UBIFS_MST_NODE_SZ != 512);
+	BUILD_BUG_ON(UBIFS_INO_NODE_SZ != 160);
+	BUILD_BUG_ON(UBIFS_REF_NODE_SZ != 64);
+
+	/*
+	 * We use 2 bit wide bit-fields to store compression type, which should
+	 * be amended if more compressors are added. The bit-fields are:
+	 * @compr_type in 'struct ubifs_inode', @default_compr in
+	 * 'struct ubifs_info' and @compr_type in 'struct ubifs_mount_opts'.
+	 */
+	BUILD_BUG_ON(UBIFS_COMPR_TYPES_CNT > 4);
+
+	/*
+	 * We require that PAGE_SIZE is greater-than-or-equal-to
+	 * UBIFS_BLOCK_SIZE. It is assumed that both are powers of 2.
+	 */
+	if (PAGE_SIZE < UBIFS_BLOCK_SIZE) {
+		pr_err("UBIFS error (pid %d): VFS page cache size is %u bytes, but UBIFS requires at least 4096 bytes",
+		       current->pid, (unsigned int)PAGE_SIZE);
+		return -EINVAL;
+	}
+
+	ubifs_inode_slab = kmem_cache_create("ubifs_inode_slab",
+				sizeof(struct ubifs_inode), 0,
+				SLAB_MEM_SPREAD | SLAB_RECLAIM_ACCOUNT |
+				SLAB_ACCOUNT, &inode_slab_ctor);
+	if (!ubifs_inode_slab)
+		return -ENOMEM;
+
+	ubifs_shrinker_info = shrinker_alloc(0, "ubifs-slab");
+	if (!ubifs_shrinker_info)
+		goto out_slab;
+
+	ubifs_shrinker_info->count_objects = ubifs_shrink_count;
+	ubifs_shrinker_info->scan_objects = ubifs_shrink_scan;
+
+	shrinker_register(ubifs_shrinker_info);
+
+	err = ubifs_compressors_init();
+	if (err)
+		goto out_shrinker;
+
+	dbg_debugfs_init();
+
+	err = ubifs_sysfs_init();
+	if (err)
+		goto out_dbg;
+
+	err = register_filesystem(&ubifs_fs_type);
+	if (err) {
+		pr_err("UBIFS error (pid %d): cannot register file system, error %d",
+		       current->pid, err);
+		goto out_sysfs;
+	}
+	return 0;
+
+out_sysfs:
+	ubifs_sysfs_exit();
+out_dbg:
+	dbg_debugfs_exit();
+	ubifs_compressors_exit();
+out_shrinker:
+	shrinker_free(ubifs_shrinker_info);
+out_slab:
+	kmem_cache_destroy(ubifs_inode_slab);
+	return err;
+}
+/* late_initcall to let compressors initialize first */
+late_initcall(ubifs_init);
+
+static void __exit ubifs_exit(void)
+{
+	WARN_ON(!list_empty(&ubifs_infos));
+	WARN_ON(atomic_long_read(&ubifs_clean_zn_cnt) != 0);
+
+	dbg_debugfs_exit();
+	ubifs_sysfs_exit();
+	ubifs_compressors_exit();
+	shrinker_free(ubifs_shrinker_info);
+
+	/*
+	 * Make sure all delayed rcu free inodes are flushed before we
+	 * destroy cache.
+	 */
+	rcu_barrier();
+	kmem_cache_destroy(ubifs_inode_slab);
+	unregister_filesystem(&ubifs_fs_type);
+}
+module_exit(ubifs_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_VERSION(__stringify(UBIFS_VERSION));
+MODULE_AUTHOR("Artem Bityutskiy, Adrian Hunter");
+MODULE_DESCRIPTION("UBIFS - UBI File System");
diff --git a/ubifs-utils/libubifs/tnc.c b/ubifs-utils/libubifs/tnc.c
new file mode 100644
index 00000000..0fabecd9
--- /dev/null
+++ b/ubifs-utils/libubifs/tnc.c
@@ -0,0 +1,3553 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file implements TNC (Tree Node Cache) which caches indexing nodes of
+ * the UBIFS B-tree.
+ *
+ * At the moment the locking rules of the TNC tree are quite simple and
+ * straightforward. We just have a mutex and lock it when we traverse the
+ * tree. If a znode is not in memory, we read it from flash while still having
+ * the mutex locked.
+ */
+
+#include <linux/crc32.h>
+#include <linux/slab.h>
+#include "ubifs.h"
+
+static int try_read_node(const struct ubifs_info *c, void *buf, int type,
+			 struct ubifs_zbranch *zbr);
+static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
+			      struct ubifs_zbranch *zbr, void *node);
+
+/*
+ * Returned codes of 'matches_name()' and 'fallible_matches_name()' functions.
+ * @NAME_LESS: name corresponding to the first argument is less than second
+ * @NAME_MATCHES: names match
+ * @NAME_GREATER: name corresponding to the second argument is greater than
+ *                first
+ * @NOT_ON_MEDIA: node referred by zbranch does not exist on the media
+ *
+ * These constants were introduce to improve readability.
+ */
+enum {
+	NAME_LESS    = 0,
+	NAME_MATCHES = 1,
+	NAME_GREATER = 2,
+	NOT_ON_MEDIA = 3,
+};
+
+static void do_insert_old_idx(struct ubifs_info *c,
+			      struct ubifs_old_idx *old_idx)
+{
+	struct ubifs_old_idx *o;
+	struct rb_node **p, *parent = NULL;
+
+	p = &c->old_idx.rb_node;
+	while (*p) {
+		parent = *p;
+		o = rb_entry(parent, struct ubifs_old_idx, rb);
+		if (old_idx->lnum < o->lnum)
+			p = &(*p)->rb_left;
+		else if (old_idx->lnum > o->lnum)
+			p = &(*p)->rb_right;
+		else if (old_idx->offs < o->offs)
+			p = &(*p)->rb_left;
+		else if (old_idx->offs > o->offs)
+			p = &(*p)->rb_right;
+		else {
+			ubifs_err(c, "old idx added twice!");
+			kfree(old_idx);
+			return;
+		}
+	}
+	rb_link_node(&old_idx->rb, parent, p);
+	rb_insert_color(&old_idx->rb, &c->old_idx);
+}
+
+/**
+ * insert_old_idx - record an index node obsoleted since the last commit start.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number of obsoleted index node
+ * @offs: offset of obsoleted index node
+ *
+ * Returns %0 on success, and a negative error code on failure.
+ *
+ * For recovery, there must always be a complete intact version of the index on
+ * flash at all times. That is called the "old index". It is the index as at the
+ * time of the last successful commit. Many of the index nodes in the old index
+ * may be dirty, but they must not be erased until the next successful commit
+ * (at which point that index becomes the old index).
+ *
+ * That means that the garbage collection and the in-the-gaps method of
+ * committing must be able to determine if an index node is in the old index.
+ * Most of the old index nodes can be found by looking up the TNC using the
+ * 'lookup_znode()' function. However, some of the old index nodes may have
+ * been deleted from the current index or may have been changed so much that
+ * they cannot be easily found. In those cases, an entry is added to an RB-tree.
+ * That is what this function does. The RB-tree is ordered by LEB number and
+ * offset because they uniquely identify the old index node.
+ */
+static int insert_old_idx(struct ubifs_info *c, int lnum, int offs)
+{
+	struct ubifs_old_idx *old_idx;
+
+	old_idx = kmalloc(sizeof(struct ubifs_old_idx), GFP_NOFS);
+	if (unlikely(!old_idx))
+		return -ENOMEM;
+	old_idx->lnum = lnum;
+	old_idx->offs = offs;
+	do_insert_old_idx(c, old_idx);
+
+	return 0;
+}
+
+/**
+ * insert_old_idx_znode - record a znode obsoleted since last commit start.
+ * @c: UBIFS file-system description object
+ * @znode: znode of obsoleted index node
+ *
+ * Returns %0 on success, and a negative error code on failure.
+ */
+int insert_old_idx_znode(struct ubifs_info *c, struct ubifs_znode *znode)
+{
+	if (znode->parent) {
+		struct ubifs_zbranch *zbr;
+
+		zbr = &znode->parent->zbranch[znode->iip];
+		if (zbr->len)
+			return insert_old_idx(c, zbr->lnum, zbr->offs);
+	} else
+		if (c->zroot.len)
+			return insert_old_idx(c, c->zroot.lnum,
+					      c->zroot.offs);
+	return 0;
+}
+
+/**
+ * ins_clr_old_idx_znode - record a znode obsoleted since last commit start.
+ * @c: UBIFS file-system description object
+ * @znode: znode of obsoleted index node
+ *
+ * Returns %0 on success, and a negative error code on failure.
+ */
+static int ins_clr_old_idx_znode(struct ubifs_info *c,
+				 struct ubifs_znode *znode)
+{
+	int err;
+
+	if (znode->parent) {
+		struct ubifs_zbranch *zbr;
+
+		zbr = &znode->parent->zbranch[znode->iip];
+		if (zbr->len) {
+			err = insert_old_idx(c, zbr->lnum, zbr->offs);
+			if (err)
+				return err;
+			zbr->lnum = 0;
+			zbr->offs = 0;
+			zbr->len = 0;
+		}
+	} else
+		if (c->zroot.len) {
+			err = insert_old_idx(c, c->zroot.lnum, c->zroot.offs);
+			if (err)
+				return err;
+			c->zroot.lnum = 0;
+			c->zroot.offs = 0;
+			c->zroot.len = 0;
+		}
+	return 0;
+}
+
+/**
+ * destroy_old_idx - destroy the old_idx RB-tree.
+ * @c: UBIFS file-system description object
+ *
+ * During start commit, the old_idx RB-tree is used to avoid overwriting index
+ * nodes that were in the index last commit but have since been deleted.  This
+ * is necessary for recovery i.e. the old index must be kept intact until the
+ * new index is successfully written.  The old-idx RB-tree is used for the
+ * in-the-gaps method of writing index nodes and is destroyed every commit.
+ */
+void destroy_old_idx(struct ubifs_info *c)
+{
+	struct ubifs_old_idx *old_idx, *n;
+
+	rbtree_postorder_for_each_entry_safe(old_idx, n, &c->old_idx, rb)
+		kfree(old_idx);
+
+	c->old_idx = RB_ROOT;
+}
+
+/**
+ * copy_znode - copy a dirty znode.
+ * @c: UBIFS file-system description object
+ * @znode: znode to copy
+ *
+ * A dirty znode being committed may not be changed, so it is copied.
+ */
+static struct ubifs_znode *copy_znode(struct ubifs_info *c,
+				      struct ubifs_znode *znode)
+{
+	struct ubifs_znode *zn;
+
+	zn = kmemdup(znode, c->max_znode_sz, GFP_NOFS);
+	if (unlikely(!zn))
+		return ERR_PTR(-ENOMEM);
+
+	zn->cnext = NULL;
+	__set_bit(DIRTY_ZNODE, &zn->flags);
+	__clear_bit(COW_ZNODE, &zn->flags);
+
+	return zn;
+}
+
+/**
+ * add_idx_dirt - add dirt due to a dirty znode.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number of index node
+ * @dirt: size of index node
+ *
+ * This function updates lprops dirty space and the new size of the index.
+ */
+static int add_idx_dirt(struct ubifs_info *c, int lnum, int dirt)
+{
+	c->calc_idx_sz -= ALIGN(dirt, 8);
+	return ubifs_add_dirt(c, lnum, dirt);
+}
+
+/**
+ * replace_znode - replace old znode with new znode.
+ * @c: UBIFS file-system description object
+ * @new_zn: new znode
+ * @old_zn: old znode
+ * @zbr: the branch of parent znode
+ *
+ * Replace old znode with new znode in TNC.
+ */
+static void replace_znode(struct ubifs_info *c, struct ubifs_znode *new_zn,
+			  struct ubifs_znode *old_zn, struct ubifs_zbranch *zbr)
+{
+	ubifs_assert(c, !ubifs_zn_obsolete(old_zn));
+	__set_bit(OBSOLETE_ZNODE, &old_zn->flags);
+
+	if (old_zn->level != 0) {
+		int i;
+		const int n = new_zn->child_cnt;
+
+		/* The children now have new parent */
+		for (i = 0; i < n; i++) {
+			struct ubifs_zbranch *child = &new_zn->zbranch[i];
+
+			if (child->znode)
+				child->znode->parent = new_zn;
+		}
+	}
+
+	zbr->znode = new_zn;
+	zbr->lnum = 0;
+	zbr->offs = 0;
+	zbr->len = 0;
+
+	atomic_long_inc(&c->dirty_zn_cnt);
+}
+
+/**
+ * dirty_cow_znode - ensure a znode is not being committed.
+ * @c: UBIFS file-system description object
+ * @zbr: branch of znode to check
+ *
+ * Returns dirtied znode on success or negative error code on failure.
+ */
+static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c,
+					   struct ubifs_zbranch *zbr)
+{
+	struct ubifs_znode *znode = zbr->znode;
+	struct ubifs_znode *zn;
+	int err;
+
+	if (!ubifs_zn_cow(znode)) {
+		/* znode is not being committed */
+		if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) {
+			atomic_long_inc(&c->dirty_zn_cnt);
+			atomic_long_dec(&c->clean_zn_cnt);
+			atomic_long_dec(&ubifs_clean_zn_cnt);
+			err = add_idx_dirt(c, zbr->lnum, zbr->len);
+			if (unlikely(err))
+				return ERR_PTR(err);
+		}
+		return znode;
+	}
+
+	zn = copy_znode(c, znode);
+	if (IS_ERR(zn))
+		return zn;
+
+	if (zbr->len) {
+		struct ubifs_old_idx *old_idx;
+
+		old_idx = kmalloc(sizeof(struct ubifs_old_idx), GFP_NOFS);
+		if (unlikely(!old_idx)) {
+			err = -ENOMEM;
+			goto out;
+		}
+		old_idx->lnum = zbr->lnum;
+		old_idx->offs = zbr->offs;
+
+		err = add_idx_dirt(c, zbr->lnum, zbr->len);
+		if (err) {
+			kfree(old_idx);
+			goto out;
+		}
+
+		do_insert_old_idx(c, old_idx);
+	}
+
+	replace_znode(c, zn, znode, zbr);
+
+	return zn;
+
+out:
+	kfree(zn);
+	return ERR_PTR(err);
+}
+
+/**
+ * lnc_add - add a leaf node to the leaf node cache.
+ * @c: UBIFS file-system description object
+ * @zbr: zbranch of leaf node
+ * @node: leaf node
+ *
+ * Leaf nodes are non-index nodes directory entry nodes or data nodes. The
+ * purpose of the leaf node cache is to save re-reading the same leaf node over
+ * and over again. Most things are cached by VFS, however the file system must
+ * cache directory entries for readdir and for resolving hash collisions. The
+ * present implementation of the leaf node cache is extremely simple, and
+ * allows for error returns that are not used but that may be needed if a more
+ * complex implementation is created.
+ *
+ * Note, this function does not add the @node object to LNC directly, but
+ * allocates a copy of the object and adds the copy to LNC. The reason for this
+ * is that @node has been allocated outside of the TNC subsystem and will be
+ * used with @c->tnc_mutex unlock upon return from the TNC subsystem. But LNC
+ * may be changed at any time, e.g. freed by the shrinker.
+ */
+static int lnc_add(struct ubifs_info *c, struct ubifs_zbranch *zbr,
+		   const void *node)
+{
+	int err;
+	void *lnc_node;
+	const struct ubifs_dent_node *dent = node;
+
+	ubifs_assert(c, !zbr->leaf);
+	ubifs_assert(c, zbr->len != 0);
+	ubifs_assert(c, is_hash_key(c, &zbr->key));
+
+	err = ubifs_validate_entry(c, dent);
+	if (err) {
+		dump_stack();
+		ubifs_dump_node(c, dent, zbr->len);
+		return err;
+	}
+
+	lnc_node = kmemdup(node, zbr->len, GFP_NOFS);
+	if (!lnc_node)
+		/* We don't have to have the cache, so no error */
+		return 0;
+
+	zbr->leaf = lnc_node;
+	return 0;
+}
+
+ /**
+ * lnc_add_directly - add a leaf node to the leaf-node-cache.
+ * @c: UBIFS file-system description object
+ * @zbr: zbranch of leaf node
+ * @node: leaf node
+ *
+ * This function is similar to 'lnc_add()', but it does not create a copy of
+ * @node but inserts @node to TNC directly.
+ */
+static int lnc_add_directly(struct ubifs_info *c, struct ubifs_zbranch *zbr,
+			    void *node)
+{
+	int err;
+
+	ubifs_assert(c, !zbr->leaf);
+	ubifs_assert(c, zbr->len != 0);
+
+	err = ubifs_validate_entry(c, node);
+	if (err) {
+		dump_stack();
+		ubifs_dump_node(c, node, zbr->len);
+		return err;
+	}
+
+	zbr->leaf = node;
+	return 0;
+}
+
+/**
+ * lnc_free - remove a leaf node from the leaf node cache.
+ * @zbr: zbranch of leaf node
+ */
+static void lnc_free(struct ubifs_zbranch *zbr)
+{
+	if (!zbr->leaf)
+		return;
+	kfree(zbr->leaf);
+	zbr->leaf = NULL;
+}
+
+/**
+ * tnc_read_hashed_node - read a "hashed" leaf node.
+ * @c: UBIFS file-system description object
+ * @zbr: key and position of the node
+ * @node: node is returned here
+ *
+ * This function reads a "hashed" node defined by @zbr from the leaf node cache
+ * (in it is there) or from the hash media, in which case the node is also
+ * added to LNC. Returns zero in case of success or a negative error
+ * code in case of failure.
+ */
+static int tnc_read_hashed_node(struct ubifs_info *c, struct ubifs_zbranch *zbr,
+				void *node)
+{
+	int err;
+
+	ubifs_assert(c, is_hash_key(c, &zbr->key));
+
+	if (zbr->leaf) {
+		/* Read from the leaf node cache */
+		ubifs_assert(c, zbr->len != 0);
+		memcpy(node, zbr->leaf, zbr->len);
+		return 0;
+	}
+
+	if (c->replaying) {
+		err = fallible_read_node(c, &zbr->key, zbr, node);
+		/*
+		 * When the node was not found, return -ENOENT, 0 otherwise.
+		 * Negative return codes stay as-is.
+		 */
+		if (err == 0)
+			err = -ENOENT;
+		else if (err == 1)
+			err = 0;
+	} else {
+		err = ubifs_tnc_read_node(c, zbr, node);
+	}
+	if (err)
+		return err;
+
+	/* Add the node to the leaf node cache */
+	err = lnc_add(c, zbr, node);
+	return err;
+}
+
+/**
+ * try_read_node - read a node if it is a node.
+ * @c: UBIFS file-system description object
+ * @buf: buffer to read to
+ * @type: node type
+ * @zbr: the zbranch describing the node to read
+ *
+ * This function tries to read a node of known type and length, checks it and
+ * stores it in @buf. This function returns %1 if a node is present and %0 if
+ * a node is not present. A negative error code is returned for I/O errors.
+ * This function performs that same function as ubifs_read_node except that
+ * it does not require that there is actually a node present and instead
+ * the return code indicates if a node was read.
+ *
+ * Note, this function does not check CRC of data nodes if @c->no_chk_data_crc
+ * is true (it is controlled by corresponding mount option). However, if
+ * @c->mounting or @c->remounting_rw is true (we are mounting or re-mounting to
+ * R/W mode), @c->no_chk_data_crc is ignored and CRC is checked. This is
+ * because during mounting or re-mounting from R/O mode to R/W mode we may read
+ * journal nodes (when replying the journal or doing the recovery) and the
+ * journal nodes may potentially be corrupted, so checking is required.
+ */
+static int try_read_node(const struct ubifs_info *c, void *buf, int type,
+			 struct ubifs_zbranch *zbr)
+{
+	int len = zbr->len;
+	int lnum = zbr->lnum;
+	int offs = zbr->offs;
+	int err, node_len;
+	struct ubifs_ch *ch = buf;
+	uint32_t crc, node_crc;
+
+	dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
+
+	err = ubifs_leb_read(c, lnum, buf, offs, len, 1);
+	if (err) {
+		ubifs_err(c, "cannot read node type %d from LEB %d:%d, error %d",
+			  type, lnum, offs, err);
+		return err;
+	}
+
+	if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC)
+		return 0;
+
+	if (ch->node_type != type)
+		return 0;
+
+	node_len = le32_to_cpu(ch->len);
+	if (node_len != len)
+		return 0;
+
+	if (type != UBIFS_DATA_NODE || !c->no_chk_data_crc || c->mounting ||
+	    c->remounting_rw) {
+		crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
+		node_crc = le32_to_cpu(ch->crc);
+		if (crc != node_crc)
+			return 0;
+	}
+
+	err = ubifs_node_check_hash(c, buf, zbr->hash);
+	if (err) {
+		ubifs_bad_hash(c, buf, zbr->hash, lnum, offs);
+		return 0;
+	}
+
+	return 1;
+}
+
+/**
+ * fallible_read_node - try to read a leaf node.
+ * @c: UBIFS file-system description object
+ * @key:  key of node to read
+ * @zbr:  position of node
+ * @node: node returned
+ *
+ * This function tries to read a node and returns %1 if the node is read, %0
+ * if the node is not present, and a negative error code in the case of error.
+ */
+static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
+			      struct ubifs_zbranch *zbr, void *node)
+{
+	int ret;
+
+	dbg_tnck(key, "LEB %d:%d, key ", zbr->lnum, zbr->offs);
+
+	ret = try_read_node(c, node, key_type(c, key), zbr);
+	if (ret == 1) {
+		union ubifs_key node_key;
+		struct ubifs_dent_node *dent = node;
+
+		/* All nodes have key in the same place */
+		key_read(c, &dent->key, &node_key);
+		if (keys_cmp(c, key, &node_key) != 0)
+			ret = 0;
+	}
+	if (ret == 0 && c->replaying)
+		dbg_mntk(key, "dangling branch LEB %d:%d len %d, key ",
+			zbr->lnum, zbr->offs, zbr->len);
+	return ret;
+}
+
+/**
+ * matches_name - determine if a direntry or xattr entry matches a given name.
+ * @c: UBIFS file-system description object
+ * @zbr: zbranch of dent
+ * @nm: name to match
+ *
+ * This function checks if xentry/direntry referred by zbranch @zbr matches name
+ * @nm. Returns %NAME_MATCHES if it does, %NAME_LESS if the name referred by
+ * @zbr is less than @nm, and %NAME_GREATER if it is greater than @nm. In case
+ * of failure, a negative error code is returned.
+ */
+static int matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr,
+			const struct fscrypt_name *nm)
+{
+	struct ubifs_dent_node *dent;
+	int nlen, err;
+
+	/* If possible, match against the dent in the leaf node cache */
+	if (!zbr->leaf) {
+		dent = kmalloc(zbr->len, GFP_NOFS);
+		if (!dent)
+			return -ENOMEM;
+
+		err = ubifs_tnc_read_node(c, zbr, dent);
+		if (err)
+			goto out_free;
+
+		/* Add the node to the leaf node cache */
+		err = lnc_add_directly(c, zbr, dent);
+		if (err)
+			goto out_free;
+	} else
+		dent = zbr->leaf;
+
+	nlen = le16_to_cpu(dent->nlen);
+	err = memcmp(dent->name, fname_name(nm), min_t(int, nlen, fname_len(nm)));
+	if (err == 0) {
+		if (nlen == fname_len(nm))
+			return NAME_MATCHES;
+		else if (nlen < fname_len(nm))
+			return NAME_LESS;
+		else
+			return NAME_GREATER;
+	} else if (err < 0)
+		return NAME_LESS;
+	else
+		return NAME_GREATER;
+
+out_free:
+	kfree(dent);
+	return err;
+}
+
+/**
+ * get_znode - get a TNC znode that may not be loaded yet.
+ * @c: UBIFS file-system description object
+ * @znode: parent znode
+ * @n: znode branch slot number
+ *
+ * This function returns the znode or a negative error code.
+ */
+static struct ubifs_znode *get_znode(struct ubifs_info *c,
+				     struct ubifs_znode *znode, int n)
+{
+	struct ubifs_zbranch *zbr;
+
+	zbr = &znode->zbranch[n];
+	if (zbr->znode)
+		znode = zbr->znode;
+	else
+		znode = ubifs_load_znode(c, zbr, znode, n);
+	return znode;
+}
+
+/**
+ * tnc_next - find next TNC entry.
+ * @c: UBIFS file-system description object
+ * @zn: znode is passed and returned here
+ * @n: znode branch slot number is passed and returned here
+ *
+ * This function returns %0 if the next TNC entry is found, %-ENOENT if there is
+ * no next entry, or a negative error code otherwise.
+ */
+static int tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
+{
+	struct ubifs_znode *znode = *zn;
+	int nn = *n;
+
+	nn += 1;
+	if (nn < znode->child_cnt) {
+		*n = nn;
+		return 0;
+	}
+	while (1) {
+		struct ubifs_znode *zp;
+
+		zp = znode->parent;
+		if (!zp)
+			return -ENOENT;
+		nn = znode->iip + 1;
+		znode = zp;
+		if (nn < znode->child_cnt) {
+			znode = get_znode(c, znode, nn);
+			if (IS_ERR(znode))
+				return PTR_ERR(znode);
+			while (znode->level != 0) {
+				znode = get_znode(c, znode, 0);
+				if (IS_ERR(znode))
+					return PTR_ERR(znode);
+			}
+			nn = 0;
+			break;
+		}
+	}
+	*zn = znode;
+	*n = nn;
+	return 0;
+}
+
+/**
+ * tnc_prev - find previous TNC entry.
+ * @c: UBIFS file-system description object
+ * @zn: znode is returned here
+ * @n: znode branch slot number is passed and returned here
+ *
+ * This function returns %0 if the previous TNC entry is found, %-ENOENT if
+ * there is no next entry, or a negative error code otherwise.
+ */
+static int tnc_prev(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
+{
+	struct ubifs_znode *znode = *zn;
+	int nn = *n;
+
+	if (nn > 0) {
+		*n = nn - 1;
+		return 0;
+	}
+	while (1) {
+		struct ubifs_znode *zp;
+
+		zp = znode->parent;
+		if (!zp)
+			return -ENOENT;
+		nn = znode->iip - 1;
+		znode = zp;
+		if (nn >= 0) {
+			znode = get_znode(c, znode, nn);
+			if (IS_ERR(znode))
+				return PTR_ERR(znode);
+			while (znode->level != 0) {
+				nn = znode->child_cnt - 1;
+				znode = get_znode(c, znode, nn);
+				if (IS_ERR(znode))
+					return PTR_ERR(znode);
+			}
+			nn = znode->child_cnt - 1;
+			break;
+		}
+	}
+	*zn = znode;
+	*n = nn;
+	return 0;
+}
+
+/**
+ * resolve_collision - resolve a collision.
+ * @c: UBIFS file-system description object
+ * @key: key of a directory or extended attribute entry
+ * @zn: znode is returned here
+ * @n: zbranch number is passed and returned here
+ * @nm: name of the entry
+ *
+ * This function is called for "hashed" keys to make sure that the found key
+ * really corresponds to the looked up node (directory or extended attribute
+ * entry). It returns %1 and sets @zn and @n if the collision is resolved.
+ * %0 is returned if @nm is not found and @zn and @n are set to the previous
+ * entry, i.e. to the entry after which @nm could follow if it were in TNC.
+ * This means that @n may be set to %-1 if the leftmost key in @zn is the
+ * previous one. A negative error code is returned on failures.
+ */
+static int resolve_collision(struct ubifs_info *c, const union ubifs_key *key,
+			     struct ubifs_znode **zn, int *n,
+			     const struct fscrypt_name *nm)
+{
+	int err;
+
+	err = matches_name(c, &(*zn)->zbranch[*n], nm);
+	if (unlikely(err < 0))
+		return err;
+	if (err == NAME_MATCHES)
+		return 1;
+
+	if (err == NAME_GREATER) {
+		/* Look left */
+		while (1) {
+			err = tnc_prev(c, zn, n);
+			if (err == -ENOENT) {
+				ubifs_assert(c, *n == 0);
+				*n = -1;
+				return 0;
+			}
+			if (err < 0)
+				return err;
+			if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
+				/*
+				 * We have found the branch after which we would
+				 * like to insert, but inserting in this znode
+				 * may still be wrong. Consider the following 3
+				 * znodes, in the case where we are resolving a
+				 * collision with Key2.
+				 *
+				 *                  znode zp
+				 *            ----------------------
+				 * level 1     |  Key0  |  Key1  |
+				 *            -----------------------
+				 *                 |            |
+				 *       znode za  |            |  znode zb
+				 *          ------------      ------------
+				 * level 0  |  Key0  |        |  Key2  |
+				 *          ------------      ------------
+				 *
+				 * The lookup finds Key2 in znode zb. Lets say
+				 * there is no match and the name is greater so
+				 * we look left. When we find Key0, we end up
+				 * here. If we return now, we will insert into
+				 * znode za at slot n = 1.  But that is invalid
+				 * according to the parent's keys.  Key2 must
+				 * be inserted into znode zb.
+				 *
+				 * Note, this problem is not relevant for the
+				 * case when we go right, because
+				 * 'tnc_insert()' would correct the parent key.
+				 */
+				if (*n == (*zn)->child_cnt - 1) {
+					err = tnc_next(c, zn, n);
+					if (err) {
+						/* Should be impossible */
+						ubifs_assert(c, 0);
+						if (err == -ENOENT)
+							err = -EINVAL;
+						return err;
+					}
+					ubifs_assert(c, *n == 0);
+					*n = -1;
+				}
+				return 0;
+			}
+			err = matches_name(c, &(*zn)->zbranch[*n], nm);
+			if (err < 0)
+				return err;
+			if (err == NAME_LESS)
+				return 0;
+			if (err == NAME_MATCHES)
+				return 1;
+			ubifs_assert(c, err == NAME_GREATER);
+		}
+	} else {
+		int nn = *n;
+		struct ubifs_znode *znode = *zn;
+
+		/* Look right */
+		while (1) {
+			err = tnc_next(c, &znode, &nn);
+			if (err == -ENOENT)
+				return 0;
+			if (err < 0)
+				return err;
+			if (keys_cmp(c, &znode->zbranch[nn].key, key))
+				return 0;
+			err = matches_name(c, &znode->zbranch[nn], nm);
+			if (err < 0)
+				return err;
+			if (err == NAME_GREATER)
+				return 0;
+			*zn = znode;
+			*n = nn;
+			if (err == NAME_MATCHES)
+				return 1;
+			ubifs_assert(c, err == NAME_LESS);
+		}
+	}
+}
+
+/**
+ * fallible_matches_name - determine if a dent matches a given name.
+ * @c: UBIFS file-system description object
+ * @zbr: zbranch of dent
+ * @nm: name to match
+ *
+ * This is a "fallible" version of 'matches_name()' function which does not
+ * panic if the direntry/xentry referred by @zbr does not exist on the media.
+ *
+ * This function checks if xentry/direntry referred by zbranch @zbr matches name
+ * @nm. Returns %NAME_MATCHES it does, %NAME_LESS if the name referred by @zbr
+ * is less than @nm, %NAME_GREATER if it is greater than @nm, and @NOT_ON_MEDIA
+ * if xentry/direntry referred by @zbr does not exist on the media. A negative
+ * error code is returned in case of failure.
+ */
+static int fallible_matches_name(struct ubifs_info *c,
+				 struct ubifs_zbranch *zbr,
+				 const struct fscrypt_name *nm)
+{
+	struct ubifs_dent_node *dent;
+	int nlen, err;
+
+	/* If possible, match against the dent in the leaf node cache */
+	if (!zbr->leaf) {
+		dent = kmalloc(zbr->len, GFP_NOFS);
+		if (!dent)
+			return -ENOMEM;
+
+		err = fallible_read_node(c, &zbr->key, zbr, dent);
+		if (err < 0)
+			goto out_free;
+		if (err == 0) {
+			/* The node was not present */
+			err = NOT_ON_MEDIA;
+			goto out_free;
+		}
+		ubifs_assert(c, err == 1);
+
+		err = lnc_add_directly(c, zbr, dent);
+		if (err)
+			goto out_free;
+	} else
+		dent = zbr->leaf;
+
+	nlen = le16_to_cpu(dent->nlen);
+	err = memcmp(dent->name, fname_name(nm), min_t(int, nlen, fname_len(nm)));
+	if (err == 0) {
+		if (nlen == fname_len(nm))
+			return NAME_MATCHES;
+		else if (nlen < fname_len(nm))
+			return NAME_LESS;
+		else
+			return NAME_GREATER;
+	} else if (err < 0)
+		return NAME_LESS;
+	else
+		return NAME_GREATER;
+
+out_free:
+	kfree(dent);
+	return err;
+}
+
+/**
+ * fallible_resolve_collision - resolve a collision even if nodes are missing.
+ * @c: UBIFS file-system description object
+ * @key: key
+ * @zn: znode is returned here
+ * @n: branch number is passed and returned here
+ * @nm: name of directory entry
+ * @adding: indicates caller is adding a key to the TNC
+ *
+ * This is a "fallible" version of the 'resolve_collision()' function which
+ * does not panic if one of the nodes referred to by TNC does not exist on the
+ * media. This may happen when replaying the journal if a deleted node was
+ * Garbage-collected and the commit was not done. A branch that refers to a node
+ * that is not present is called a dangling branch. The following are the return
+ * codes for this function:
+ *  o if @nm was found, %1 is returned and @zn and @n are set to the found
+ *    branch;
+ *  o if we are @adding and @nm was not found, %0 is returned;
+ *  o if we are not @adding and @nm was not found, but a dangling branch was
+ *    found, then %1 is returned and @zn and @n are set to the dangling branch;
+ *  o a negative error code is returned in case of failure.
+ */
+static int fallible_resolve_collision(struct ubifs_info *c,
+				      const union ubifs_key *key,
+				      struct ubifs_znode **zn, int *n,
+				      const struct fscrypt_name *nm,
+				      int adding)
+{
+	struct ubifs_znode *o_znode = NULL, *znode = *zn;
+	int o_n, err, cmp, unsure = 0, nn = *n;
+
+	cmp = fallible_matches_name(c, &znode->zbranch[nn], nm);
+	if (unlikely(cmp < 0))
+		return cmp;
+	if (cmp == NAME_MATCHES)
+		return 1;
+	if (cmp == NOT_ON_MEDIA) {
+		o_znode = znode;
+		o_n = nn;
+		/*
+		 * We are unlucky and hit a dangling branch straight away.
+		 * Now we do not really know where to go to find the needed
+		 * branch - to the left or to the right. Well, let's try left.
+		 */
+		unsure = 1;
+	} else if (!adding)
+		unsure = 1; /* Remove a dangling branch wherever it is */
+
+	if (cmp == NAME_GREATER || unsure) {
+		/* Look left */
+		while (1) {
+			err = tnc_prev(c, zn, n);
+			if (err == -ENOENT) {
+				ubifs_assert(c, *n == 0);
+				*n = -1;
+				break;
+			}
+			if (err < 0)
+				return err;
+			if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
+				/* See comments in 'resolve_collision()' */
+				if (*n == (*zn)->child_cnt - 1) {
+					err = tnc_next(c, zn, n);
+					if (err) {
+						/* Should be impossible */
+						ubifs_assert(c, 0);
+						if (err == -ENOENT)
+							err = -EINVAL;
+						return err;
+					}
+					ubifs_assert(c, *n == 0);
+					*n = -1;
+				}
+				break;
+			}
+			err = fallible_matches_name(c, &(*zn)->zbranch[*n], nm);
+			if (err < 0)
+				return err;
+			if (err == NAME_MATCHES)
+				return 1;
+			if (err == NOT_ON_MEDIA) {
+				o_znode = *zn;
+				o_n = *n;
+				continue;
+			}
+			if (!adding)
+				continue;
+			if (err == NAME_LESS)
+				break;
+			else
+				unsure = 0;
+		}
+	}
+
+	if (cmp == NAME_LESS || unsure) {
+		/* Look right */
+		*zn = znode;
+		*n = nn;
+		while (1) {
+			err = tnc_next(c, &znode, &nn);
+			if (err == -ENOENT)
+				break;
+			if (err < 0)
+				return err;
+			if (keys_cmp(c, &znode->zbranch[nn].key, key))
+				break;
+			err = fallible_matches_name(c, &znode->zbranch[nn], nm);
+			if (err < 0)
+				return err;
+			if (err == NAME_GREATER)
+				break;
+			*zn = znode;
+			*n = nn;
+			if (err == NAME_MATCHES)
+				return 1;
+			if (err == NOT_ON_MEDIA) {
+				o_znode = znode;
+				o_n = nn;
+			}
+		}
+	}
+
+	/* Never match a dangling branch when adding */
+	if (adding || !o_znode)
+		return 0;
+
+	dbg_mntk(key, "dangling match LEB %d:%d len %d key ",
+		o_znode->zbranch[o_n].lnum, o_znode->zbranch[o_n].offs,
+		o_znode->zbranch[o_n].len);
+	*zn = o_znode;
+	*n = o_n;
+	return 1;
+}
+
+/**
+ * matches_position - determine if a zbranch matches a given position.
+ * @zbr: zbranch of dent
+ * @lnum: LEB number of dent to match
+ * @offs: offset of dent to match
+ *
+ * This function returns %1 if @lnum:@offs matches, and %0 otherwise.
+ */
+static int matches_position(struct ubifs_zbranch *zbr, int lnum, int offs)
+{
+	if (zbr->lnum == lnum && zbr->offs == offs)
+		return 1;
+	else
+		return 0;
+}
+
+/**
+ * resolve_collision_directly - resolve a collision directly.
+ * @c: UBIFS file-system description object
+ * @key: key of directory entry
+ * @zn: znode is passed and returned here
+ * @n: zbranch number is passed and returned here
+ * @lnum: LEB number of dent node to match
+ * @offs: offset of dent node to match
+ *
+ * This function is used for "hashed" keys to make sure the found directory or
+ * extended attribute entry node is what was looked for. It is used when the
+ * flash address of the right node is known (@lnum:@offs) which makes it much
+ * easier to resolve collisions (no need to read entries and match full
+ * names). This function returns %1 and sets @zn and @n if the collision is
+ * resolved, %0 if @lnum:@offs is not found and @zn and @n are set to the
+ * previous directory entry. Otherwise a negative error code is returned.
+ */
+static int resolve_collision_directly(struct ubifs_info *c,
+				      const union ubifs_key *key,
+				      struct ubifs_znode **zn, int *n,
+				      int lnum, int offs)
+{
+	struct ubifs_znode *znode;
+	int nn, err;
+
+	znode = *zn;
+	nn = *n;
+	if (matches_position(&znode->zbranch[nn], lnum, offs))
+		return 1;
+
+	/* Look left */
+	while (1) {
+		err = tnc_prev(c, &znode, &nn);
+		if (err == -ENOENT)
+			break;
+		if (err < 0)
+			return err;
+		if (keys_cmp(c, &znode->zbranch[nn].key, key))
+			break;
+		if (matches_position(&znode->zbranch[nn], lnum, offs)) {
+			*zn = znode;
+			*n = nn;
+			return 1;
+		}
+	}
+
+	/* Look right */
+	znode = *zn;
+	nn = *n;
+	while (1) {
+		err = tnc_next(c, &znode, &nn);
+		if (err == -ENOENT)
+			return 0;
+		if (err < 0)
+			return err;
+		if (keys_cmp(c, &znode->zbranch[nn].key, key))
+			return 0;
+		*zn = znode;
+		*n = nn;
+		if (matches_position(&znode->zbranch[nn], lnum, offs))
+			return 1;
+	}
+}
+
+/**
+ * dirty_cow_bottom_up - dirty a znode and its ancestors.
+ * @c: UBIFS file-system description object
+ * @znode: znode to dirty
+ *
+ * If we do not have a unique key that resides in a znode, then we cannot
+ * dirty that znode from the top down (i.e. by using lookup_level0_dirty)
+ * This function records the path back to the last dirty ancestor, and then
+ * dirties the znodes on that path.
+ */
+static struct ubifs_znode *dirty_cow_bottom_up(struct ubifs_info *c,
+					       struct ubifs_znode *znode)
+{
+	struct ubifs_znode *zp;
+	int *path = c->bottom_up_buf, p = 0;
+
+	ubifs_assert(c, c->zroot.znode);
+	ubifs_assert(c, znode);
+	if (c->zroot.znode->level > BOTTOM_UP_HEIGHT) {
+		kfree(c->bottom_up_buf);
+		c->bottom_up_buf = kmalloc_array(c->zroot.znode->level,
+						 sizeof(int),
+						 GFP_NOFS);
+		if (!c->bottom_up_buf)
+			return ERR_PTR(-ENOMEM);
+		path = c->bottom_up_buf;
+	}
+	if (c->zroot.znode->level) {
+		/* Go up until parent is dirty */
+		while (1) {
+			int n;
+
+			zp = znode->parent;
+			if (!zp)
+				break;
+			n = znode->iip;
+			ubifs_assert(c, p < c->zroot.znode->level);
+			path[p++] = n;
+			if (!zp->cnext && ubifs_zn_dirty(znode))
+				break;
+			znode = zp;
+		}
+	}
+
+	/* Come back down, dirtying as we go */
+	while (1) {
+		struct ubifs_zbranch *zbr;
+
+		zp = znode->parent;
+		if (zp) {
+			ubifs_assert(c, path[p - 1] >= 0);
+			ubifs_assert(c, path[p - 1] < zp->child_cnt);
+			zbr = &zp->zbranch[path[--p]];
+			znode = dirty_cow_znode(c, zbr);
+		} else {
+			ubifs_assert(c, znode == c->zroot.znode);
+			znode = dirty_cow_znode(c, &c->zroot);
+		}
+		if (IS_ERR(znode) || !p)
+			break;
+		ubifs_assert(c, path[p - 1] >= 0);
+		ubifs_assert(c, path[p - 1] < znode->child_cnt);
+		znode = znode->zbranch[path[p - 1]].znode;
+	}
+
+	return znode;
+}
+
+/**
+ * ubifs_lookup_level0 - search for zero-level znode.
+ * @c: UBIFS file-system description object
+ * @key:  key to lookup
+ * @zn: znode is returned here
+ * @n: znode branch slot number is returned here
+ *
+ * This function looks up the TNC tree and search for zero-level znode which
+ * refers key @key. The found zero-level znode is returned in @zn. There are 3
+ * cases:
+ *   o exact match, i.e. the found zero-level znode contains key @key, then %1
+ *     is returned and slot number of the matched branch is stored in @n;
+ *   o not exact match, which means that zero-level znode does not contain
+ *     @key, then %0 is returned and slot number of the closest branch or %-1
+ *     is stored in @n; In this case calling tnc_next() is mandatory.
+ *   o @key is so small that it is even less than the lowest key of the
+ *     leftmost zero-level node, then %0 is returned and %0 is stored in @n.
+ *
+ * Note, when the TNC tree is traversed, some znodes may be absent, then this
+ * function reads corresponding indexing nodes and inserts them to TNC. In
+ * case of failure, a negative error code is returned.
+ */
+int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
+			struct ubifs_znode **zn, int *n)
+{
+	int err, exact;
+	struct ubifs_znode *znode;
+	time64_t time = ktime_get_seconds();
+
+	dbg_tnck(key, "search key ");
+	ubifs_assert(c, key_type(c, key) < UBIFS_INVALID_KEY);
+
+	znode = c->zroot.znode;
+	if (unlikely(!znode)) {
+		znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
+		if (IS_ERR(znode))
+			return PTR_ERR(znode);
+	}
+
+	znode->time = time;
+
+	while (1) {
+		struct ubifs_zbranch *zbr;
+
+		exact = ubifs_search_zbranch(c, znode, key, n);
+
+		if (znode->level == 0)
+			break;
+
+		if (*n < 0)
+			*n = 0;
+		zbr = &znode->zbranch[*n];
+
+		if (zbr->znode) {
+			znode->time = time;
+			znode = zbr->znode;
+			continue;
+		}
+
+		/* znode is not in TNC cache, load it from the media */
+		znode = ubifs_load_znode(c, zbr, znode, *n);
+		if (IS_ERR(znode))
+			return PTR_ERR(znode);
+	}
+
+	*zn = znode;
+	if (exact || !is_hash_key(c, key) || *n != -1) {
+		dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
+		return exact;
+	}
+
+	/*
+	 * Here is a tricky place. We have not found the key and this is a
+	 * "hashed" key, which may collide. The rest of the code deals with
+	 * situations like this:
+	 *
+	 *                  | 3 | 5 |
+	 *                  /       \
+	 *          | 3 | 5 |      | 6 | 7 | (x)
+	 *
+	 * Or more a complex example:
+	 *
+	 *                | 1 | 5 |
+	 *                /       \
+	 *       | 1 | 3 |         | 5 | 8 |
+	 *              \           /
+	 *          | 5 | 5 |   | 6 | 7 | (x)
+	 *
+	 * In the examples, if we are looking for key "5", we may reach nodes
+	 * marked with "(x)". In this case what we have do is to look at the
+	 * left and see if there is "5" key there. If there is, we have to
+	 * return it.
+	 *
+	 * Note, this whole situation is possible because we allow to have
+	 * elements which are equivalent to the next key in the parent in the
+	 * children of current znode. For example, this happens if we split a
+	 * znode like this: | 3 | 5 | 5 | 6 | 7 |, which results in something
+	 * like this:
+	 *                      | 3 | 5 |
+	 *                       /     \
+	 *                | 3 | 5 |   | 5 | 6 | 7 |
+	 *                              ^
+	 * And this becomes what is at the first "picture" after key "5" marked
+	 * with "^" is removed. What could be done is we could prohibit
+	 * splitting in the middle of the colliding sequence. Also, when
+	 * removing the leftmost key, we would have to correct the key of the
+	 * parent node, which would introduce additional complications. Namely,
+	 * if we changed the leftmost key of the parent znode, the garbage
+	 * collector would be unable to find it (GC is doing this when GC'ing
+	 * indexing LEBs). Although we already have an additional RB-tree where
+	 * we save such changed znodes (see 'ins_clr_old_idx_znode()') until
+	 * after the commit. But anyway, this does not look easy to implement
+	 * so we did not try this.
+	 */
+	err = tnc_prev(c, &znode, n);
+	if (err == -ENOENT) {
+		dbg_tnc("found 0, lvl %d, n -1", znode->level);
+		*n = -1;
+		return 0;
+	}
+	if (unlikely(err < 0))
+		return err;
+	if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
+		dbg_tnc("found 0, lvl %d, n -1", znode->level);
+		*n = -1;
+		return 0;
+	}
+
+	dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
+	*zn = znode;
+	return 1;
+}
+
+/**
+ * lookup_level0_dirty - search for zero-level znode dirtying.
+ * @c: UBIFS file-system description object
+ * @key:  key to lookup
+ * @zn: znode is returned here
+ * @n: znode branch slot number is returned here
+ *
+ * This function looks up the TNC tree and search for zero-level znode which
+ * refers key @key. The found zero-level znode is returned in @zn. There are 3
+ * cases:
+ *   o exact match, i.e. the found zero-level znode contains key @key, then %1
+ *     is returned and slot number of the matched branch is stored in @n;
+ *   o not exact match, which means that zero-level znode does not contain @key
+ *     then %0 is returned and slot number of the closed branch is stored in
+ *     @n;
+ *   o @key is so small that it is even less than the lowest key of the
+ *     leftmost zero-level node, then %0 is returned and %-1 is stored in @n.
+ *
+ * Additionally all znodes in the path from the root to the located zero-level
+ * znode are marked as dirty.
+ *
+ * Note, when the TNC tree is traversed, some znodes may be absent, then this
+ * function reads corresponding indexing nodes and inserts them to TNC. In
+ * case of failure, a negative error code is returned.
+ */
+static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key,
+			       struct ubifs_znode **zn, int *n)
+{
+	int err, exact;
+	struct ubifs_znode *znode;
+	time64_t time = ktime_get_seconds();
+
+	dbg_tnck(key, "search and dirty key ");
+
+	znode = c->zroot.znode;
+	if (unlikely(!znode)) {
+		znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
+		if (IS_ERR(znode))
+			return PTR_ERR(znode);
+	}
+
+	znode = dirty_cow_znode(c, &c->zroot);
+	if (IS_ERR(znode))
+		return PTR_ERR(znode);
+
+	znode->time = time;
+
+	while (1) {
+		struct ubifs_zbranch *zbr;
+
+		exact = ubifs_search_zbranch(c, znode, key, n);
+
+		if (znode->level == 0)
+			break;
+
+		if (*n < 0)
+			*n = 0;
+		zbr = &znode->zbranch[*n];
+
+		if (zbr->znode) {
+			znode->time = time;
+			znode = dirty_cow_znode(c, zbr);
+			if (IS_ERR(znode))
+				return PTR_ERR(znode);
+			continue;
+		}
+
+		/* znode is not in TNC cache, load it from the media */
+		znode = ubifs_load_znode(c, zbr, znode, *n);
+		if (IS_ERR(znode))
+			return PTR_ERR(znode);
+		znode = dirty_cow_znode(c, zbr);
+		if (IS_ERR(znode))
+			return PTR_ERR(znode);
+	}
+
+	*zn = znode;
+	if (exact || !is_hash_key(c, key) || *n != -1) {
+		dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
+		return exact;
+	}
+
+	/*
+	 * See huge comment at 'lookup_level0_dirty()' what is the rest of the
+	 * code.
+	 */
+	err = tnc_prev(c, &znode, n);
+	if (err == -ENOENT) {
+		*n = -1;
+		dbg_tnc("found 0, lvl %d, n -1", znode->level);
+		return 0;
+	}
+	if (unlikely(err < 0))
+		return err;
+	if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
+		*n = -1;
+		dbg_tnc("found 0, lvl %d, n -1", znode->level);
+		return 0;
+	}
+
+	if (znode->cnext || !ubifs_zn_dirty(znode)) {
+		znode = dirty_cow_bottom_up(c, znode);
+		if (IS_ERR(znode))
+			return PTR_ERR(znode);
+	}
+
+	dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
+	*zn = znode;
+	return 1;
+}
+
+/**
+ * maybe_leb_gced - determine if a LEB may have been garbage collected.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number
+ * @gc_seq1: garbage collection sequence number
+ *
+ * This function determines if @lnum may have been garbage collected since
+ * sequence number @gc_seq1. If it may have been then %1 is returned, otherwise
+ * %0 is returned.
+ */
+static int maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1)
+{
+	int gc_seq2, gced_lnum;
+
+	gced_lnum = c->gced_lnum;
+	smp_rmb();
+	gc_seq2 = c->gc_seq;
+	/* Same seq means no GC */
+	if (gc_seq1 == gc_seq2)
+		return 0;
+	/* Different by more than 1 means we don't know */
+	if (gc_seq1 + 1 != gc_seq2)
+		return 1;
+	/*
+	 * We have seen the sequence number has increased by 1. Now we need to
+	 * be sure we read the right LEB number, so read it again.
+	 */
+	smp_rmb();
+	if (gced_lnum != c->gced_lnum)
+		return 1;
+	/* Finally we can check lnum */
+	if (gced_lnum == lnum)
+		return 1;
+	return 0;
+}
+
+/**
+ * ubifs_tnc_locate - look up a file-system node and return it and its location.
+ * @c: UBIFS file-system description object
+ * @key: node key to lookup
+ * @node: the node is returned here
+ * @lnum: LEB number is returned here
+ * @offs: offset is returned here
+ *
+ * This function looks up and reads node with key @key. The caller has to make
+ * sure the @node buffer is large enough to fit the node. Returns zero in case
+ * of success, %-ENOENT if the node was not found, and a negative error code in
+ * case of failure. The node location can be returned in @lnum and @offs.
+ */
+int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key,
+		     void *node, int *lnum, int *offs)
+{
+	int found, n, err;
+	struct ubifs_znode *znode;
+	struct ubifs_zbranch *zt;
+
+	mutex_lock(&c->tnc_mutex);
+	found = ubifs_lookup_level0(c, key, &znode, &n);
+	if (!found) {
+		err = -ENOENT;
+		goto out;
+	} else if (found < 0) {
+		err = found;
+		goto out;
+	}
+	zt = &znode->zbranch[n];
+	if (lnum) {
+		*lnum = zt->lnum;
+		*offs = zt->offs;
+	}
+	if (is_hash_key(c, key)) {
+		/*
+		 * In this case the leaf node cache gets used, so we pass the
+		 * address of the zbranch and keep the mutex locked
+		 */
+		err = tnc_read_hashed_node(c, zt, node);
+		goto out;
+	}
+	err = ubifs_tnc_read_node(c, zt, node);
+
+out:
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * ubifs_tnc_get_bu_keys - lookup keys for bulk-read.
+ * @c: UBIFS file-system description object
+ * @bu: bulk-read parameters and results
+ *
+ * Lookup consecutive data node keys for the same inode that reside
+ * consecutively in the same LEB. This function returns zero in case of success
+ * and a negative error code in case of failure.
+ *
+ * Note, if the bulk-read buffer length (@bu->buf_len) is known, this function
+ * makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares
+ * maximum possible amount of nodes for bulk-read.
+ */
+int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)
+{
+	int n, err = 0, lnum = -1, offs;
+	int len;
+	unsigned int block = key_block(c, &bu->key);
+	struct ubifs_znode *znode;
+
+	bu->cnt = 0;
+	bu->blk_cnt = 0;
+	bu->eof = 0;
+
+	mutex_lock(&c->tnc_mutex);
+	/* Find first key */
+	err = ubifs_lookup_level0(c, &bu->key, &znode, &n);
+	if (err < 0)
+		goto out;
+	if (err) {
+		/* Key found */
+		len = znode->zbranch[n].len;
+		/* The buffer must be big enough for at least 1 node */
+		if (len > bu->buf_len) {
+			err = -EINVAL;
+			goto out;
+		}
+		/* Add this key */
+		bu->zbranch[bu->cnt++] = znode->zbranch[n];
+		bu->blk_cnt += 1;
+		lnum = znode->zbranch[n].lnum;
+		offs = ALIGN(znode->zbranch[n].offs + len, 8);
+	}
+	while (1) {
+		struct ubifs_zbranch *zbr;
+		union ubifs_key *key;
+		unsigned int next_block;
+
+		/* Find next key */
+		err = tnc_next(c, &znode, &n);
+		if (err)
+			goto out;
+		zbr = &znode->zbranch[n];
+		key = &zbr->key;
+		/* See if there is another data key for this file */
+		if (key_inum(c, key) != key_inum(c, &bu->key) ||
+		    key_type(c, key) != UBIFS_DATA_KEY) {
+			err = -ENOENT;
+			goto out;
+		}
+		if (lnum < 0) {
+			/* First key found */
+			lnum = zbr->lnum;
+			offs = ALIGN(zbr->offs + zbr->len, 8);
+			len = zbr->len;
+			if (len > bu->buf_len) {
+				err = -EINVAL;
+				goto out;
+			}
+		} else {
+			/*
+			 * The data nodes must be in consecutive positions in
+			 * the same LEB.
+			 */
+			if (zbr->lnum != lnum || zbr->offs != offs)
+				goto out;
+			offs += ALIGN(zbr->len, 8);
+			len = ALIGN(len, 8) + zbr->len;
+			/* Must not exceed buffer length */
+			if (len > bu->buf_len)
+				goto out;
+		}
+		/* Allow for holes */
+		next_block = key_block(c, key);
+		bu->blk_cnt += (next_block - block - 1);
+		if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
+			goto out;
+		block = next_block;
+		/* Add this key */
+		bu->zbranch[bu->cnt++] = *zbr;
+		bu->blk_cnt += 1;
+		/* See if we have room for more */
+		if (bu->cnt >= UBIFS_MAX_BULK_READ)
+			goto out;
+		if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
+			goto out;
+	}
+out:
+	if (err == -ENOENT) {
+		bu->eof = 1;
+		err = 0;
+	}
+	bu->gc_seq = c->gc_seq;
+	mutex_unlock(&c->tnc_mutex);
+	if (err)
+		return err;
+	/*
+	 * An enormous hole could cause bulk-read to encompass too many
+	 * page cache pages, so limit the number here.
+	 */
+	if (bu->blk_cnt > UBIFS_MAX_BULK_READ)
+		bu->blk_cnt = UBIFS_MAX_BULK_READ;
+	/*
+	 * Ensure that bulk-read covers a whole number of page cache
+	 * pages.
+	 */
+	if (UBIFS_BLOCKS_PER_PAGE == 1 ||
+	    !(bu->blk_cnt & (UBIFS_BLOCKS_PER_PAGE - 1)))
+		return 0;
+	if (bu->eof) {
+		/* At the end of file we can round up */
+		bu->blk_cnt += UBIFS_BLOCKS_PER_PAGE - 1;
+		return 0;
+	}
+	/* Exclude data nodes that do not make up a whole page cache page */
+	block = key_block(c, &bu->key) + bu->blk_cnt;
+	block &= ~(UBIFS_BLOCKS_PER_PAGE - 1);
+	while (bu->cnt) {
+		if (key_block(c, &bu->zbranch[bu->cnt - 1].key) < block)
+			break;
+		bu->cnt -= 1;
+	}
+	return 0;
+}
+
+/**
+ * read_wbuf - bulk-read from a LEB with a wbuf.
+ * @wbuf: wbuf that may overlap the read
+ * @buf: buffer into which to read
+ * @len: read length
+ * @lnum: LEB number from which to read
+ * @offs: offset from which to read
+ *
+ * This functions returns %0 on success or a negative error code on failure.
+ */
+static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum,
+		     int offs)
+{
+	const struct ubifs_info *c = wbuf->c;
+	int rlen, overlap;
+
+	dbg_io("LEB %d:%d, length %d", lnum, offs, len);
+	ubifs_assert(c, wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
+	ubifs_assert(c, !(offs & 7) && offs < c->leb_size);
+	ubifs_assert(c, offs + len <= c->leb_size);
+
+	spin_lock(&wbuf->lock);
+	overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
+	if (!overlap) {
+		/* We may safely unlock the write-buffer and read the data */
+		spin_unlock(&wbuf->lock);
+		return ubifs_leb_read(c, lnum, buf, offs, len, 0);
+	}
+
+	/* Don't read under wbuf */
+	rlen = wbuf->offs - offs;
+	if (rlen < 0)
+		rlen = 0;
+
+	/* Copy the rest from the write-buffer */
+	memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
+	spin_unlock(&wbuf->lock);
+
+	if (rlen > 0)
+		/* Read everything that goes before write-buffer */
+		return ubifs_leb_read(c, lnum, buf, offs, rlen, 0);
+
+	return 0;
+}
+
+/**
+ * validate_data_node - validate data nodes for bulk-read.
+ * @c: UBIFS file-system description object
+ * @buf: buffer containing data node to validate
+ * @zbr: zbranch of data node to validate
+ *
+ * This functions returns %0 on success or a negative error code on failure.
+ */
+static int validate_data_node(struct ubifs_info *c, void *buf,
+			      struct ubifs_zbranch *zbr)
+{
+	union ubifs_key key1;
+	struct ubifs_ch *ch = buf;
+	int err, len;
+
+	if (ch->node_type != UBIFS_DATA_NODE) {
+		ubifs_err(c, "bad node type (%d but expected %d)",
+			  ch->node_type, UBIFS_DATA_NODE);
+		goto out_err;
+	}
+
+	err = ubifs_check_node(c, buf, zbr->len, zbr->lnum, zbr->offs, 0, 0);
+	if (err) {
+		ubifs_err(c, "expected node type %d", UBIFS_DATA_NODE);
+		goto out;
+	}
+
+	err = ubifs_node_check_hash(c, buf, zbr->hash);
+	if (err) {
+		ubifs_bad_hash(c, buf, zbr->hash, zbr->lnum, zbr->offs);
+		return err;
+	}
+
+	len = le32_to_cpu(ch->len);
+	if (len != zbr->len) {
+		ubifs_err(c, "bad node length %d, expected %d", len, zbr->len);
+		goto out_err;
+	}
+
+	/* Make sure the key of the read node is correct */
+	key_read(c, buf + UBIFS_KEY_OFFSET, &key1);
+	if (!keys_eq(c, &zbr->key, &key1)) {
+		ubifs_err(c, "bad key in node at LEB %d:%d",
+			  zbr->lnum, zbr->offs);
+		dbg_tnck(&zbr->key, "looked for key ");
+		dbg_tnck(&key1, "found node's key ");
+		goto out_err;
+	}
+
+	return 0;
+
+out_err:
+	err = -EINVAL;
+out:
+	ubifs_err(c, "bad node at LEB %d:%d", zbr->lnum, zbr->offs);
+	ubifs_dump_node(c, buf, zbr->len);
+	dump_stack();
+	return err;
+}
+
+/**
+ * ubifs_tnc_bulk_read - read a number of data nodes in one go.
+ * @c: UBIFS file-system description object
+ * @bu: bulk-read parameters and results
+ *
+ * This functions reads and validates the data nodes that were identified by the
+ * 'ubifs_tnc_get_bu_keys()' function. This functions returns %0 on success,
+ * -EAGAIN to indicate a race with GC, or another negative error code on
+ * failure.
+ */
+int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu)
+{
+	int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i;
+	struct ubifs_wbuf *wbuf;
+	void *buf;
+
+	len = bu->zbranch[bu->cnt - 1].offs;
+	len += bu->zbranch[bu->cnt - 1].len - offs;
+	if (len > bu->buf_len) {
+		ubifs_err(c, "buffer too small %d vs %d", bu->buf_len, len);
+		return -EINVAL;
+	}
+
+	/* Do the read */
+	wbuf = ubifs_get_wbuf(c, lnum);
+	if (wbuf)
+		err = read_wbuf(wbuf, bu->buf, len, lnum, offs);
+	else
+		err = ubifs_leb_read(c, lnum, bu->buf, offs, len, 0);
+
+	/* Check for a race with GC */
+	if (maybe_leb_gced(c, lnum, bu->gc_seq))
+		return -EAGAIN;
+
+	if (err && err != -EBADMSG) {
+		ubifs_err(c, "failed to read from LEB %d:%d, error %d",
+			  lnum, offs, err);
+		dump_stack();
+		dbg_tnck(&bu->key, "key ");
+		return err;
+	}
+
+	/* Validate the nodes read */
+	buf = bu->buf;
+	for (i = 0; i < bu->cnt; i++) {
+		err = validate_data_node(c, buf, &bu->zbranch[i]);
+		if (err)
+			return err;
+		buf = buf + ALIGN(bu->zbranch[i].len, 8);
+	}
+
+	return 0;
+}
+
+/**
+ * do_lookup_nm- look up a "hashed" node.
+ * @c: UBIFS file-system description object
+ * @key: node key to lookup
+ * @node: the node is returned here
+ * @nm: node name
+ *
+ * This function looks up and reads a node which contains name hash in the key.
+ * Since the hash may have collisions, there may be many nodes with the same
+ * key, so we have to sequentially look to all of them until the needed one is
+ * found. This function returns zero in case of success, %-ENOENT if the node
+ * was not found, and a negative error code in case of failure.
+ */
+static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
+			void *node, const struct fscrypt_name *nm)
+{
+	int found, n, err;
+	struct ubifs_znode *znode;
+
+	dbg_tnck(key, "key ");
+	mutex_lock(&c->tnc_mutex);
+	found = ubifs_lookup_level0(c, key, &znode, &n);
+	if (!found) {
+		err = -ENOENT;
+		goto out_unlock;
+	} else if (found < 0) {
+		err = found;
+		goto out_unlock;
+	}
+
+	ubifs_assert(c, n >= 0);
+
+	err = resolve_collision(c, key, &znode, &n, nm);
+	dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
+	if (unlikely(err < 0))
+		goto out_unlock;
+	if (err == 0) {
+		err = -ENOENT;
+		goto out_unlock;
+	}
+
+	err = tnc_read_hashed_node(c, &znode->zbranch[n], node);
+
+out_unlock:
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * ubifs_tnc_lookup_nm - look up a "hashed" node.
+ * @c: UBIFS file-system description object
+ * @key: node key to lookup
+ * @node: the node is returned here
+ * @nm: node name
+ *
+ * This function looks up and reads a node which contains name hash in the key.
+ * Since the hash may have collisions, there may be many nodes with the same
+ * key, so we have to sequentially look to all of them until the needed one is
+ * found. This function returns zero in case of success, %-ENOENT if the node
+ * was not found, and a negative error code in case of failure.
+ */
+int ubifs_tnc_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
+			void *node, const struct fscrypt_name *nm)
+{
+	int err, len;
+	const struct ubifs_dent_node *dent = node;
+
+	/*
+	 * We assume that in most of the cases there are no name collisions and
+	 * 'ubifs_tnc_lookup()' returns us the right direntry.
+	 */
+	err = ubifs_tnc_lookup(c, key, node);
+	if (err)
+		return err;
+
+	len = le16_to_cpu(dent->nlen);
+	if (fname_len(nm) == len && !memcmp(dent->name, fname_name(nm), len))
+		return 0;
+
+	/*
+	 * Unluckily, there are hash collisions and we have to iterate over
+	 * them look at each direntry with colliding name hash sequentially.
+	 */
+
+	return do_lookup_nm(c, key, node, nm);
+}
+
+static int search_dh_cookie(struct ubifs_info *c, const union ubifs_key *key,
+			    struct ubifs_dent_node *dent, uint32_t cookie,
+			    struct ubifs_znode **zn, int *n, int exact)
+{
+	int err;
+	struct ubifs_znode *znode = *zn;
+	struct ubifs_zbranch *zbr;
+	union ubifs_key *dkey;
+
+	if (!exact) {
+		err = tnc_next(c, &znode, n);
+		if (err)
+			return err;
+	}
+
+	for (;;) {
+		zbr = &znode->zbranch[*n];
+		dkey = &zbr->key;
+
+		if (key_inum(c, dkey) != key_inum(c, key) ||
+		    key_type(c, dkey) != key_type(c, key)) {
+			return -ENOENT;
+		}
+
+		err = tnc_read_hashed_node(c, zbr, dent);
+		if (err)
+			return err;
+
+		if (key_hash(c, key) == key_hash(c, dkey) &&
+		    le32_to_cpu(dent->cookie) == cookie) {
+			*zn = znode;
+			return 0;
+		}
+
+		err = tnc_next(c, &znode, n);
+		if (err)
+			return err;
+	}
+}
+
+static int do_lookup_dh(struct ubifs_info *c, const union ubifs_key *key,
+			struct ubifs_dent_node *dent, uint32_t cookie)
+{
+	int n, err;
+	struct ubifs_znode *znode;
+	union ubifs_key start_key;
+
+	ubifs_assert(c, is_hash_key(c, key));
+
+	lowest_dent_key(c, &start_key, key_inum(c, key));
+
+	mutex_lock(&c->tnc_mutex);
+	err = ubifs_lookup_level0(c, &start_key, &znode, &n);
+	if (unlikely(err < 0))
+		goto out_unlock;
+
+	err = search_dh_cookie(c, key, dent, cookie, &znode, &n, err);
+
+out_unlock:
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * ubifs_tnc_lookup_dh - look up a "double hashed" node.
+ * @c: UBIFS file-system description object
+ * @key: node key to lookup
+ * @node: the node is returned here
+ * @cookie: node cookie for collision resolution
+ *
+ * This function looks up and reads a node which contains name hash in the key.
+ * Since the hash may have collisions, there may be many nodes with the same
+ * key, so we have to sequentially look to all of them until the needed one
+ * with the same cookie value is found.
+ * This function returns zero in case of success, %-ENOENT if the node
+ * was not found, and a negative error code in case of failure.
+ */
+int ubifs_tnc_lookup_dh(struct ubifs_info *c, const union ubifs_key *key,
+			void *node, uint32_t cookie)
+{
+	int err;
+	const struct ubifs_dent_node *dent = node;
+
+	if (!c->double_hash)
+		return -EOPNOTSUPP;
+
+	/*
+	 * We assume that in most of the cases there are no name collisions and
+	 * 'ubifs_tnc_lookup()' returns us the right direntry.
+	 */
+	err = ubifs_tnc_lookup(c, key, node);
+	if (err)
+		return err;
+
+	if (le32_to_cpu(dent->cookie) == cookie)
+		return 0;
+
+	/*
+	 * Unluckily, there are hash collisions and we have to iterate over
+	 * them look at each direntry with colliding name hash sequentially.
+	 */
+	return do_lookup_dh(c, key, node, cookie);
+}
+
+/**
+ * correct_parent_keys - correct parent znodes' keys.
+ * @c: UBIFS file-system description object
+ * @znode: znode to correct parent znodes for
+ *
+ * This is a helper function for 'tnc_insert()'. When the key of the leftmost
+ * zbranch changes, keys of parent znodes have to be corrected. This helper
+ * function is called in such situations and corrects the keys if needed.
+ */
+static void correct_parent_keys(const struct ubifs_info *c,
+				struct ubifs_znode *znode)
+{
+	union ubifs_key *key, *key1;
+
+	ubifs_assert(c, znode->parent);
+	ubifs_assert(c, znode->iip == 0);
+
+	key = &znode->zbranch[0].key;
+	key1 = &znode->parent->zbranch[0].key;
+
+	while (keys_cmp(c, key, key1) < 0) {
+		key_copy(c, key, key1);
+		znode = znode->parent;
+		znode->alt = 1;
+		if (!znode->parent || znode->iip)
+			break;
+		key1 = &znode->parent->zbranch[0].key;
+	}
+}
+
+/**
+ * insert_zbranch - insert a zbranch into a znode.
+ * @c: UBIFS file-system description object
+ * @znode: znode into which to insert
+ * @zbr: zbranch to insert
+ * @n: slot number to insert to
+ *
+ * This is a helper function for 'tnc_insert()'. UBIFS does not allow "gaps" in
+ * znode's array of zbranches and keeps zbranches consolidated, so when a new
+ * zbranch has to be inserted to the @znode->zbranches[]' array at the @n-th
+ * slot, zbranches starting from @n have to be moved right.
+ */
+static void insert_zbranch(struct ubifs_info *c, struct ubifs_znode *znode,
+			   const struct ubifs_zbranch *zbr, int n)
+{
+	int i;
+
+	ubifs_assert(c, ubifs_zn_dirty(znode));
+
+	if (znode->level) {
+		for (i = znode->child_cnt; i > n; i--) {
+			znode->zbranch[i] = znode->zbranch[i - 1];
+			if (znode->zbranch[i].znode)
+				znode->zbranch[i].znode->iip = i;
+		}
+		if (zbr->znode)
+			zbr->znode->iip = n;
+	} else
+		for (i = znode->child_cnt; i > n; i--)
+			znode->zbranch[i] = znode->zbranch[i - 1];
+
+	znode->zbranch[n] = *zbr;
+	znode->child_cnt += 1;
+
+	/*
+	 * After inserting at slot zero, the lower bound of the key range of
+	 * this znode may have changed. If this znode is subsequently split
+	 * then the upper bound of the key range may change, and furthermore
+	 * it could change to be lower than the original lower bound. If that
+	 * happens, then it will no longer be possible to find this znode in the
+	 * TNC using the key from the index node on flash. That is bad because
+	 * if it is not found, we will assume it is obsolete and may overwrite
+	 * it. Then if there is an unclean unmount, we will start using the
+	 * old index which will be broken.
+	 *
+	 * So we first mark znodes that have insertions at slot zero, and then
+	 * if they are split we add their lnum/offs to the old_idx tree.
+	 */
+	if (n == 0)
+		znode->alt = 1;
+}
+
+/**
+ * tnc_insert - insert a node into TNC.
+ * @c: UBIFS file-system description object
+ * @znode: znode to insert into
+ * @zbr: branch to insert
+ * @n: slot number to insert new zbranch to
+ *
+ * This function inserts a new node described by @zbr into znode @znode. If
+ * znode does not have a free slot for new zbranch, it is split. Parent znodes
+ * are splat as well if needed. Returns zero in case of success or a negative
+ * error code in case of failure.
+ */
+static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode,
+		      struct ubifs_zbranch *zbr, int n)
+{
+	struct ubifs_znode *zn, *zi, *zp;
+	int i, keep, move, appending = 0;
+	union ubifs_key *key = &zbr->key, *key1;
+
+	ubifs_assert(c, n >= 0 && n <= c->fanout);
+
+	/* Implement naive insert for now */
+again:
+	zp = znode->parent;
+	if (znode->child_cnt < c->fanout) {
+		ubifs_assert(c, n != c->fanout);
+		dbg_tnck(key, "inserted at %d level %d, key ", n, znode->level);
+
+		insert_zbranch(c, znode, zbr, n);
+
+		/* Ensure parent's key is correct */
+		if (n == 0 && zp && znode->iip == 0)
+			correct_parent_keys(c, znode);
+
+		return 0;
+	}
+
+	/*
+	 * Unfortunately, @znode does not have more empty slots and we have to
+	 * split it.
+	 */
+	dbg_tnck(key, "splitting level %d, key ", znode->level);
+
+	if (znode->alt)
+		/*
+		 * We can no longer be sure of finding this znode by key, so we
+		 * record it in the old_idx tree.
+		 */
+		ins_clr_old_idx_znode(c, znode);
+
+	zn = kzalloc(c->max_znode_sz, GFP_NOFS);
+	if (!zn)
+		return -ENOMEM;
+	zn->parent = zp;
+	zn->level = znode->level;
+
+	/* Decide where to split */
+	if (znode->level == 0 && key_type(c, key) == UBIFS_DATA_KEY) {
+		/* Try not to split consecutive data keys */
+		if (n == c->fanout) {
+			key1 = &znode->zbranch[n - 1].key;
+			if (key_inum(c, key1) == key_inum(c, key) &&
+			    key_type(c, key1) == UBIFS_DATA_KEY)
+				appending = 1;
+		} else
+			goto check_split;
+	} else if (appending && n != c->fanout) {
+		/* Try not to split consecutive data keys */
+		appending = 0;
+check_split:
+		if (n >= (c->fanout + 1) / 2) {
+			key1 = &znode->zbranch[0].key;
+			if (key_inum(c, key1) == key_inum(c, key) &&
+			    key_type(c, key1) == UBIFS_DATA_KEY) {
+				key1 = &znode->zbranch[n].key;
+				if (key_inum(c, key1) != key_inum(c, key) ||
+				    key_type(c, key1) != UBIFS_DATA_KEY) {
+					keep = n;
+					move = c->fanout - keep;
+					zi = znode;
+					goto do_split;
+				}
+			}
+		}
+	}
+
+	if (appending) {
+		keep = c->fanout;
+		move = 0;
+	} else {
+		keep = (c->fanout + 1) / 2;
+		move = c->fanout - keep;
+	}
+
+	/*
+	 * Although we don't at present, we could look at the neighbors and see
+	 * if we can move some zbranches there.
+	 */
+
+	if (n < keep) {
+		/* Insert into existing znode */
+		zi = znode;
+		move += 1;
+		keep -= 1;
+	} else {
+		/* Insert into new znode */
+		zi = zn;
+		n -= keep;
+		/* Re-parent */
+		if (zn->level != 0)
+			zbr->znode->parent = zn;
+	}
+
+do_split:
+
+	__set_bit(DIRTY_ZNODE, &zn->flags);
+	atomic_long_inc(&c->dirty_zn_cnt);
+
+	zn->child_cnt = move;
+	znode->child_cnt = keep;
+
+	dbg_tnc("moving %d, keeping %d", move, keep);
+
+	/* Move zbranch */
+	for (i = 0; i < move; i++) {
+		zn->zbranch[i] = znode->zbranch[keep + i];
+		/* Re-parent */
+		if (zn->level != 0)
+			if (zn->zbranch[i].znode) {
+				zn->zbranch[i].znode->parent = zn;
+				zn->zbranch[i].znode->iip = i;
+			}
+	}
+
+	/* Insert new key and branch */
+	dbg_tnck(key, "inserting at %d level %d, key ", n, zn->level);
+
+	insert_zbranch(c, zi, zbr, n);
+
+	/* Insert new znode (produced by spitting) into the parent */
+	if (zp) {
+		if (n == 0 && zi == znode && znode->iip == 0)
+			correct_parent_keys(c, znode);
+
+		/* Locate insertion point */
+		n = znode->iip + 1;
+
+		/* Tail recursion */
+		zbr->key = zn->zbranch[0].key;
+		zbr->znode = zn;
+		zbr->lnum = 0;
+		zbr->offs = 0;
+		zbr->len = 0;
+		znode = zp;
+
+		goto again;
+	}
+
+	/* We have to split root znode */
+	dbg_tnc("creating new zroot at level %d", znode->level + 1);
+
+	zi = kzalloc(c->max_znode_sz, GFP_NOFS);
+	if (!zi)
+		return -ENOMEM;
+
+	zi->child_cnt = 2;
+	zi->level = znode->level + 1;
+
+	__set_bit(DIRTY_ZNODE, &zi->flags);
+	atomic_long_inc(&c->dirty_zn_cnt);
+
+	zi->zbranch[0].key = znode->zbranch[0].key;
+	zi->zbranch[0].znode = znode;
+	zi->zbranch[0].lnum = c->zroot.lnum;
+	zi->zbranch[0].offs = c->zroot.offs;
+	zi->zbranch[0].len = c->zroot.len;
+	zi->zbranch[1].key = zn->zbranch[0].key;
+	zi->zbranch[1].znode = zn;
+
+	c->zroot.lnum = 0;
+	c->zroot.offs = 0;
+	c->zroot.len = 0;
+	c->zroot.znode = zi;
+
+	zn->parent = zi;
+	zn->iip = 1;
+	znode->parent = zi;
+	znode->iip = 0;
+
+	return 0;
+}
+
+/**
+ * ubifs_tnc_add - add a node to TNC.
+ * @c: UBIFS file-system description object
+ * @key: key to add
+ * @lnum: LEB number of node
+ * @offs: node offset
+ * @len: node length
+ * @hash: The hash over the node
+ *
+ * This function adds a node with key @key to TNC. The node may be new or it may
+ * obsolete some existing one. Returns %0 on success or negative error code on
+ * failure.
+ */
+int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum,
+		  int offs, int len, const u8 *hash)
+{
+	int found, n, err = 0;
+	struct ubifs_znode *znode;
+
+	mutex_lock(&c->tnc_mutex);
+	dbg_tnck(key, "%d:%d, len %d, key ", lnum, offs, len);
+	found = lookup_level0_dirty(c, key, &znode, &n);
+	if (!found) {
+		struct ubifs_zbranch zbr;
+
+		zbr.znode = NULL;
+		zbr.lnum = lnum;
+		zbr.offs = offs;
+		zbr.len = len;
+		ubifs_copy_hash(c, hash, zbr.hash);
+		key_copy(c, key, &zbr.key);
+		err = tnc_insert(c, znode, &zbr, n + 1);
+	} else if (found == 1) {
+		struct ubifs_zbranch *zbr = &znode->zbranch[n];
+
+		lnc_free(zbr);
+		err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
+		zbr->lnum = lnum;
+		zbr->offs = offs;
+		zbr->len = len;
+		ubifs_copy_hash(c, hash, zbr->hash);
+	} else
+		err = found;
+	if (!err)
+		err = dbg_check_tnc(c, 0);
+	mutex_unlock(&c->tnc_mutex);
+
+	return err;
+}
+
+/**
+ * ubifs_tnc_replace - replace a node in the TNC only if the old node is found.
+ * @c: UBIFS file-system description object
+ * @key: key to add
+ * @old_lnum: LEB number of old node
+ * @old_offs: old node offset
+ * @lnum: LEB number of node
+ * @offs: node offset
+ * @len: node length
+ *
+ * This function replaces a node with key @key in the TNC only if the old node
+ * is found.  This function is called by garbage collection when node are moved.
+ * Returns %0 on success or negative error code on failure.
+ */
+int ubifs_tnc_replace(struct ubifs_info *c, const union ubifs_key *key,
+		      int old_lnum, int old_offs, int lnum, int offs, int len)
+{
+	int found, n, err = 0;
+	struct ubifs_znode *znode;
+
+	mutex_lock(&c->tnc_mutex);
+	dbg_tnck(key, "old LEB %d:%d, new LEB %d:%d, len %d, key ", old_lnum,
+		 old_offs, lnum, offs, len);
+	found = lookup_level0_dirty(c, key, &znode, &n);
+	if (found < 0) {
+		err = found;
+		goto out_unlock;
+	}
+
+	if (found == 1) {
+		struct ubifs_zbranch *zbr = &znode->zbranch[n];
+
+		found = 0;
+		if (zbr->lnum == old_lnum && zbr->offs == old_offs) {
+			lnc_free(zbr);
+			err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
+			if (err)
+				goto out_unlock;
+			zbr->lnum = lnum;
+			zbr->offs = offs;
+			zbr->len = len;
+			found = 1;
+		} else if (is_hash_key(c, key)) {
+			found = resolve_collision_directly(c, key, &znode, &n,
+							   old_lnum, old_offs);
+			dbg_tnc("rc returned %d, znode %p, n %d, LEB %d:%d",
+				found, znode, n, old_lnum, old_offs);
+			if (found < 0) {
+				err = found;
+				goto out_unlock;
+			}
+
+			if (found) {
+				/* Ensure the znode is dirtied */
+				if (znode->cnext || !ubifs_zn_dirty(znode)) {
+					znode = dirty_cow_bottom_up(c, znode);
+					if (IS_ERR(znode)) {
+						err = PTR_ERR(znode);
+						goto out_unlock;
+					}
+				}
+				zbr = &znode->zbranch[n];
+				lnc_free(zbr);
+				err = ubifs_add_dirt(c, zbr->lnum,
+						     zbr->len);
+				if (err)
+					goto out_unlock;
+				zbr->lnum = lnum;
+				zbr->offs = offs;
+				zbr->len = len;
+			}
+		}
+	}
+
+	if (!found)
+		err = ubifs_add_dirt(c, lnum, len);
+
+	if (!err)
+		err = dbg_check_tnc(c, 0);
+
+out_unlock:
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * ubifs_tnc_add_nm - add a "hashed" node to TNC.
+ * @c: UBIFS file-system description object
+ * @key: key to add
+ * @lnum: LEB number of node
+ * @offs: node offset
+ * @len: node length
+ * @hash: The hash over the node
+ * @nm: node name
+ *
+ * This is the same as 'ubifs_tnc_add()' but it should be used with keys which
+ * may have collisions, like directory entry keys.
+ */
+int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
+		     int lnum, int offs, int len, const u8 *hash,
+		     const struct fscrypt_name *nm)
+{
+	int found, n, err = 0;
+	struct ubifs_znode *znode;
+
+	mutex_lock(&c->tnc_mutex);
+	dbg_tnck(key, "LEB %d:%d, key ", lnum, offs);
+	found = lookup_level0_dirty(c, key, &znode, &n);
+	if (found < 0) {
+		err = found;
+		goto out_unlock;
+	}
+
+	if (found == 1) {
+		if (c->replaying)
+			found = fallible_resolve_collision(c, key, &znode, &n,
+							   nm, 1);
+		else
+			found = resolve_collision(c, key, &znode, &n, nm);
+		dbg_tnc("rc returned %d, znode %p, n %d", found, znode, n);
+		if (found < 0) {
+			err = found;
+			goto out_unlock;
+		}
+
+		/* Ensure the znode is dirtied */
+		if (znode->cnext || !ubifs_zn_dirty(znode)) {
+			znode = dirty_cow_bottom_up(c, znode);
+			if (IS_ERR(znode)) {
+				err = PTR_ERR(znode);
+				goto out_unlock;
+			}
+		}
+
+		if (found == 1) {
+			struct ubifs_zbranch *zbr = &znode->zbranch[n];
+
+			lnc_free(zbr);
+			err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
+			zbr->lnum = lnum;
+			zbr->offs = offs;
+			zbr->len = len;
+			ubifs_copy_hash(c, hash, zbr->hash);
+			goto out_unlock;
+		}
+	}
+
+	if (!found) {
+		struct ubifs_zbranch zbr;
+
+		zbr.znode = NULL;
+		zbr.lnum = lnum;
+		zbr.offs = offs;
+		zbr.len = len;
+		ubifs_copy_hash(c, hash, zbr.hash);
+		key_copy(c, key, &zbr.key);
+		err = tnc_insert(c, znode, &zbr, n + 1);
+		if (err)
+			goto out_unlock;
+		if (c->replaying) {
+			/*
+			 * We did not find it in the index so there may be a
+			 * dangling branch still in the index. So we remove it
+			 * by passing 'ubifs_tnc_remove_nm()' the same key but
+			 * an unmatchable name.
+			 */
+			struct fscrypt_name noname = { .disk_name = { .name = "", .len = 1 } };
+
+			err = dbg_check_tnc(c, 0);
+			mutex_unlock(&c->tnc_mutex);
+			if (err)
+				return err;
+			return ubifs_tnc_remove_nm(c, key, &noname);
+		}
+	}
+
+out_unlock:
+	if (!err)
+		err = dbg_check_tnc(c, 0);
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * tnc_delete - delete a znode form TNC.
+ * @c: UBIFS file-system description object
+ * @znode: znode to delete from
+ * @n: zbranch slot number to delete
+ *
+ * This function deletes a leaf node from @n-th slot of @znode. Returns zero in
+ * case of success and a negative error code in case of failure.
+ */
+static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n)
+{
+	struct ubifs_zbranch *zbr;
+	struct ubifs_znode *zp;
+	int i, err;
+
+	/* Delete without merge for now */
+	ubifs_assert(c, znode->level == 0);
+	ubifs_assert(c, n >= 0 && n < c->fanout);
+	dbg_tnck(&znode->zbranch[n].key, "deleting key ");
+
+	zbr = &znode->zbranch[n];
+	lnc_free(zbr);
+
+	err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
+	if (err) {
+		ubifs_dump_znode(c, znode);
+		return err;
+	}
+
+	/* We do not "gap" zbranch slots */
+	for (i = n; i < znode->child_cnt - 1; i++)
+		znode->zbranch[i] = znode->zbranch[i + 1];
+	znode->child_cnt -= 1;
+
+	if (znode->child_cnt > 0)
+		return 0;
+
+	/*
+	 * This was the last zbranch, we have to delete this znode from the
+	 * parent.
+	 */
+
+	do {
+		ubifs_assert(c, !ubifs_zn_obsolete(znode));
+		ubifs_assert(c, ubifs_zn_dirty(znode));
+
+		zp = znode->parent;
+		n = znode->iip;
+
+		atomic_long_dec(&c->dirty_zn_cnt);
+
+		err = insert_old_idx_znode(c, znode);
+		if (err)
+			return err;
+
+		if (znode->cnext) {
+			__set_bit(OBSOLETE_ZNODE, &znode->flags);
+			atomic_long_inc(&c->clean_zn_cnt);
+			atomic_long_inc(&ubifs_clean_zn_cnt);
+		} else
+			kfree(znode);
+		znode = zp;
+	} while (znode->child_cnt == 1); /* while removing last child */
+
+	/* Remove from znode, entry n - 1 */
+	znode->child_cnt -= 1;
+	ubifs_assert(c, znode->level != 0);
+	for (i = n; i < znode->child_cnt; i++) {
+		znode->zbranch[i] = znode->zbranch[i + 1];
+		if (znode->zbranch[i].znode)
+			znode->zbranch[i].znode->iip = i;
+	}
+
+	/*
+	 * If this is the root and it has only 1 child then
+	 * collapse the tree.
+	 */
+	if (!znode->parent) {
+		while (znode->child_cnt == 1 && znode->level != 0) {
+			zp = znode;
+			zbr = &znode->zbranch[0];
+			znode = get_znode(c, znode, 0);
+			if (IS_ERR(znode))
+				return PTR_ERR(znode);
+			znode = dirty_cow_znode(c, zbr);
+			if (IS_ERR(znode))
+				return PTR_ERR(znode);
+			znode->parent = NULL;
+			znode->iip = 0;
+			if (c->zroot.len) {
+				err = insert_old_idx(c, c->zroot.lnum,
+						     c->zroot.offs);
+				if (err)
+					return err;
+			}
+			c->zroot.lnum = zbr->lnum;
+			c->zroot.offs = zbr->offs;
+			c->zroot.len = zbr->len;
+			c->zroot.znode = znode;
+			ubifs_assert(c, !ubifs_zn_obsolete(zp));
+			ubifs_assert(c, ubifs_zn_dirty(zp));
+			atomic_long_dec(&c->dirty_zn_cnt);
+
+			if (zp->cnext) {
+				__set_bit(OBSOLETE_ZNODE, &zp->flags);
+				atomic_long_inc(&c->clean_zn_cnt);
+				atomic_long_inc(&ubifs_clean_zn_cnt);
+			} else
+				kfree(zp);
+		}
+	}
+
+	return 0;
+}
+
+/**
+ * ubifs_tnc_remove - remove an index entry of a node.
+ * @c: UBIFS file-system description object
+ * @key: key of node
+ *
+ * Returns %0 on success or negative error code on failure.
+ */
+int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key)
+{
+	int found, n, err = 0;
+	struct ubifs_znode *znode;
+
+	mutex_lock(&c->tnc_mutex);
+	dbg_tnck(key, "key ");
+	found = lookup_level0_dirty(c, key, &znode, &n);
+	if (found < 0) {
+		err = found;
+		goto out_unlock;
+	}
+	if (found == 1)
+		err = tnc_delete(c, znode, n);
+	if (!err)
+		err = dbg_check_tnc(c, 0);
+
+out_unlock:
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * ubifs_tnc_remove_nm - remove an index entry for a "hashed" node.
+ * @c: UBIFS file-system description object
+ * @key: key of node
+ * @nm: directory entry name
+ *
+ * Returns %0 on success or negative error code on failure.
+ */
+int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
+			const struct fscrypt_name *nm)
+{
+	int n, err;
+	struct ubifs_znode *znode;
+
+	mutex_lock(&c->tnc_mutex);
+	dbg_tnck(key, "key ");
+	err = lookup_level0_dirty(c, key, &znode, &n);
+	if (err < 0)
+		goto out_unlock;
+
+	if (err) {
+		if (c->replaying)
+			err = fallible_resolve_collision(c, key, &znode, &n,
+							 nm, 0);
+		else
+			err = resolve_collision(c, key, &znode, &n, nm);
+		dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
+		if (err < 0)
+			goto out_unlock;
+		if (err) {
+			/* Ensure the znode is dirtied */
+			if (znode->cnext || !ubifs_zn_dirty(znode)) {
+				znode = dirty_cow_bottom_up(c, znode);
+				if (IS_ERR(znode)) {
+					err = PTR_ERR(znode);
+					goto out_unlock;
+				}
+			}
+			err = tnc_delete(c, znode, n);
+		}
+	}
+
+out_unlock:
+	if (!err)
+		err = dbg_check_tnc(c, 0);
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * ubifs_tnc_remove_dh - remove an index entry for a "double hashed" node.
+ * @c: UBIFS file-system description object
+ * @key: key of node
+ * @cookie: node cookie for collision resolution
+ *
+ * Returns %0 on success or negative error code on failure.
+ */
+int ubifs_tnc_remove_dh(struct ubifs_info *c, const union ubifs_key *key,
+			uint32_t cookie)
+{
+	int n, err;
+	struct ubifs_znode *znode;
+	struct ubifs_dent_node *dent;
+	struct ubifs_zbranch *zbr;
+
+	if (!c->double_hash)
+		return -EOPNOTSUPP;
+
+	mutex_lock(&c->tnc_mutex);
+	err = lookup_level0_dirty(c, key, &znode, &n);
+	if (err <= 0)
+		goto out_unlock;
+
+	zbr = &znode->zbranch[n];
+	dent = kmalloc(UBIFS_MAX_DENT_NODE_SZ, GFP_NOFS);
+	if (!dent) {
+		err = -ENOMEM;
+		goto out_unlock;
+	}
+
+	err = tnc_read_hashed_node(c, zbr, dent);
+	if (err)
+		goto out_free;
+
+	/* If the cookie does not match, we're facing a hash collision. */
+	if (le32_to_cpu(dent->cookie) != cookie) {
+		union ubifs_key start_key;
+
+		lowest_dent_key(c, &start_key, key_inum(c, key));
+
+		err = ubifs_lookup_level0(c, &start_key, &znode, &n);
+		if (unlikely(err < 0))
+			goto out_free;
+
+		err = search_dh_cookie(c, key, dent, cookie, &znode, &n, err);
+		if (err)
+			goto out_free;
+	}
+
+	if (znode->cnext || !ubifs_zn_dirty(znode)) {
+		znode = dirty_cow_bottom_up(c, znode);
+		if (IS_ERR(znode)) {
+			err = PTR_ERR(znode);
+			goto out_free;
+		}
+	}
+	err = tnc_delete(c, znode, n);
+
+out_free:
+	kfree(dent);
+out_unlock:
+	if (!err)
+		err = dbg_check_tnc(c, 0);
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * key_in_range - determine if a key falls within a range of keys.
+ * @c: UBIFS file-system description object
+ * @key: key to check
+ * @from_key: lowest key in range
+ * @to_key: highest key in range
+ *
+ * This function returns %1 if the key is in range and %0 otherwise.
+ */
+static int key_in_range(struct ubifs_info *c, union ubifs_key *key,
+			union ubifs_key *from_key, union ubifs_key *to_key)
+{
+	if (keys_cmp(c, key, from_key) < 0)
+		return 0;
+	if (keys_cmp(c, key, to_key) > 0)
+		return 0;
+	return 1;
+}
+
+/**
+ * ubifs_tnc_remove_range - remove index entries in range.
+ * @c: UBIFS file-system description object
+ * @from_key: lowest key to remove
+ * @to_key: highest key to remove
+ *
+ * This function removes index entries starting at @from_key and ending at
+ * @to_key.  This function returns zero in case of success and a negative error
+ * code in case of failure.
+ */
+int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key,
+			   union ubifs_key *to_key)
+{
+	int i, n, k, err = 0;
+	struct ubifs_znode *znode;
+	union ubifs_key *key;
+
+	mutex_lock(&c->tnc_mutex);
+	while (1) {
+		/* Find first level 0 znode that contains keys to remove */
+		err = ubifs_lookup_level0(c, from_key, &znode, &n);
+		if (err < 0)
+			goto out_unlock;
+
+		if (err)
+			key = from_key;
+		else {
+			err = tnc_next(c, &znode, &n);
+			if (err == -ENOENT) {
+				err = 0;
+				goto out_unlock;
+			}
+			if (err < 0)
+				goto out_unlock;
+			key = &znode->zbranch[n].key;
+			if (!key_in_range(c, key, from_key, to_key)) {
+				err = 0;
+				goto out_unlock;
+			}
+		}
+
+		/* Ensure the znode is dirtied */
+		if (znode->cnext || !ubifs_zn_dirty(znode)) {
+			znode = dirty_cow_bottom_up(c, znode);
+			if (IS_ERR(znode)) {
+				err = PTR_ERR(znode);
+				goto out_unlock;
+			}
+		}
+
+		/* Remove all keys in range except the first */
+		for (i = n + 1, k = 0; i < znode->child_cnt; i++, k++) {
+			key = &znode->zbranch[i].key;
+			if (!key_in_range(c, key, from_key, to_key))
+				break;
+			lnc_free(&znode->zbranch[i]);
+			err = ubifs_add_dirt(c, znode->zbranch[i].lnum,
+					     znode->zbranch[i].len);
+			if (err) {
+				ubifs_dump_znode(c, znode);
+				goto out_unlock;
+			}
+			dbg_tnck(key, "removing key ");
+		}
+		if (k) {
+			for (i = n + 1 + k; i < znode->child_cnt; i++)
+				znode->zbranch[i - k] = znode->zbranch[i];
+			znode->child_cnt -= k;
+		}
+
+		/* Now delete the first */
+		err = tnc_delete(c, znode, n);
+		if (err)
+			goto out_unlock;
+	}
+
+out_unlock:
+	if (!err)
+		err = dbg_check_tnc(c, 0);
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * ubifs_tnc_remove_ino - remove an inode from TNC.
+ * @c: UBIFS file-system description object
+ * @inum: inode number to remove
+ *
+ * This function remove inode @inum and all the extended attributes associated
+ * with the anode from TNC and returns zero in case of success or a negative
+ * error code in case of failure.
+ */
+int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum)
+{
+	union ubifs_key key1, key2;
+	struct ubifs_dent_node *xent, *pxent = NULL;
+	struct fscrypt_name nm = {0};
+
+	dbg_tnc("ino %lu", (unsigned long)inum);
+
+	/*
+	 * Walk all extended attribute entries and remove them together with
+	 * corresponding extended attribute inodes.
+	 */
+	lowest_xent_key(c, &key1, inum);
+	while (1) {
+		ino_t xattr_inum;
+		int err;
+
+		xent = ubifs_tnc_next_ent(c, &key1, &nm);
+		if (IS_ERR(xent)) {
+			err = PTR_ERR(xent);
+			if (err == -ENOENT)
+				break;
+			kfree(pxent);
+			return err;
+		}
+
+		xattr_inum = le64_to_cpu(xent->inum);
+		dbg_tnc("xent '%s', ino %lu", xent->name,
+			(unsigned long)xattr_inum);
+
+		ubifs_evict_xattr_inode(c, xattr_inum);
+
+		fname_name(&nm) = xent->name;
+		fname_len(&nm) = le16_to_cpu(xent->nlen);
+		err = ubifs_tnc_remove_nm(c, &key1, &nm);
+		if (err) {
+			kfree(pxent);
+			kfree(xent);
+			return err;
+		}
+
+		lowest_ino_key(c, &key1, xattr_inum);
+		highest_ino_key(c, &key2, xattr_inum);
+		err = ubifs_tnc_remove_range(c, &key1, &key2);
+		if (err) {
+			kfree(pxent);
+			kfree(xent);
+			return err;
+		}
+
+		kfree(pxent);
+		pxent = xent;
+		key_read(c, &xent->key, &key1);
+	}
+
+	kfree(pxent);
+	lowest_ino_key(c, &key1, inum);
+	highest_ino_key(c, &key2, inum);
+
+	return ubifs_tnc_remove_range(c, &key1, &key2);
+}
+
+/**
+ * ubifs_tnc_next_ent - walk directory or extended attribute entries.
+ * @c: UBIFS file-system description object
+ * @key: key of last entry
+ * @nm: name of last entry found or %NULL
+ *
+ * This function finds and reads the next directory or extended attribute entry
+ * after the given key (@key) if there is one. @nm is used to resolve
+ * collisions.
+ *
+ * If the name of the current entry is not known and only the key is known,
+ * @nm->name has to be %NULL. In this case the semantics of this function is a
+ * little bit different and it returns the entry corresponding to this key, not
+ * the next one. If the key was not found, the closest "right" entry is
+ * returned.
+ *
+ * If the fist entry has to be found, @key has to contain the lowest possible
+ * key value for this inode and @name has to be %NULL.
+ *
+ * This function returns the found directory or extended attribute entry node
+ * in case of success, %-ENOENT is returned if no entry was found, and a
+ * negative error code is returned in case of failure.
+ */
+struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c,
+					   union ubifs_key *key,
+					   const struct fscrypt_name *nm)
+{
+	int n, err, type = key_type(c, key);
+	struct ubifs_znode *znode;
+	struct ubifs_dent_node *dent;
+	struct ubifs_zbranch *zbr;
+	union ubifs_key *dkey;
+
+	dbg_tnck(key, "key ");
+	ubifs_assert(c, is_hash_key(c, key));
+
+	mutex_lock(&c->tnc_mutex);
+	err = ubifs_lookup_level0(c, key, &znode, &n);
+	if (unlikely(err < 0))
+		goto out_unlock;
+
+	if (fname_len(nm) > 0) {
+		if (err) {
+			/* Handle collisions */
+			if (c->replaying)
+				err = fallible_resolve_collision(c, key, &znode, &n,
+							 nm, 0);
+			else
+				err = resolve_collision(c, key, &znode, &n, nm);
+			dbg_tnc("rc returned %d, znode %p, n %d",
+				err, znode, n);
+			if (unlikely(err < 0))
+				goto out_unlock;
+		}
+
+		/* Now find next entry */
+		err = tnc_next(c, &znode, &n);
+		if (unlikely(err))
+			goto out_unlock;
+	} else {
+		/*
+		 * The full name of the entry was not given, in which case the
+		 * behavior of this function is a little different and it
+		 * returns current entry, not the next one.
+		 */
+		if (!err) {
+			/*
+			 * However, the given key does not exist in the TNC
+			 * tree and @znode/@n variables contain the closest
+			 * "preceding" element. Switch to the next one.
+			 */
+			err = tnc_next(c, &znode, &n);
+			if (err)
+				goto out_unlock;
+		}
+	}
+
+	zbr = &znode->zbranch[n];
+	dent = kmalloc(zbr->len, GFP_NOFS);
+	if (unlikely(!dent)) {
+		err = -ENOMEM;
+		goto out_unlock;
+	}
+
+	/*
+	 * The above 'tnc_next()' call could lead us to the next inode, check
+	 * this.
+	 */
+	dkey = &zbr->key;
+	if (key_inum(c, dkey) != key_inum(c, key) ||
+	    key_type(c, dkey) != type) {
+		err = -ENOENT;
+		goto out_free;
+	}
+
+	err = tnc_read_hashed_node(c, zbr, dent);
+	if (unlikely(err))
+		goto out_free;
+
+	mutex_unlock(&c->tnc_mutex);
+	return dent;
+
+out_free:
+	kfree(dent);
+out_unlock:
+	mutex_unlock(&c->tnc_mutex);
+	return ERR_PTR(err);
+}
+
+/**
+ * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit.
+ * @c: UBIFS file-system description object
+ *
+ * Destroy left-over obsolete znodes from a failed commit.
+ */
+static void tnc_destroy_cnext(struct ubifs_info *c)
+{
+	struct ubifs_znode *cnext;
+
+	if (!c->cnext)
+		return;
+	ubifs_assert(c, c->cmt_state == COMMIT_BROKEN);
+	cnext = c->cnext;
+	do {
+		struct ubifs_znode *znode = cnext;
+
+		cnext = cnext->cnext;
+		if (ubifs_zn_obsolete(znode))
+			kfree(znode);
+		else if (!ubifs_zn_cow(znode)) {
+			/*
+			 * Don't forget to update clean znode count after
+			 * committing failed, because ubifs will check this
+			 * count while closing tnc. Non-obsolete znode could
+			 * be re-dirtied during committing process, so dirty
+			 * flag is untrustable. The flag 'COW_ZNODE' is set
+			 * for each dirty znode before committing, and it is
+			 * cleared as long as the znode become clean, so we
+			 * can statistic clean znode count according to this
+			 * flag.
+			 */
+			atomic_long_inc(&c->clean_zn_cnt);
+			atomic_long_inc(&ubifs_clean_zn_cnt);
+		}
+	} while (cnext && cnext != c->cnext);
+}
+
+/**
+ * ubifs_tnc_close - close TNC subsystem and free all related resources.
+ * @c: UBIFS file-system description object
+ */
+void ubifs_tnc_close(struct ubifs_info *c)
+{
+	tnc_destroy_cnext(c);
+	ubifs_destroy_tnc_tree(c);
+	kfree(c->gap_lebs);
+	kfree(c->ilebs);
+	destroy_old_idx(c);
+}
+
+/**
+ * left_znode - get the znode to the left.
+ * @c: UBIFS file-system description object
+ * @znode: znode
+ *
+ * This function returns a pointer to the znode to the left of @znode or NULL if
+ * there is not one. A negative error code is returned on failure.
+ */
+static struct ubifs_znode *left_znode(struct ubifs_info *c,
+				      struct ubifs_znode *znode)
+{
+	int level = znode->level;
+
+	while (1) {
+		int n = znode->iip - 1;
+
+		/* Go up until we can go left */
+		znode = znode->parent;
+		if (!znode)
+			return NULL;
+		if (n >= 0) {
+			/* Now go down the rightmost branch to 'level' */
+			znode = get_znode(c, znode, n);
+			if (IS_ERR(znode))
+				return znode;
+			while (znode->level != level) {
+				n = znode->child_cnt - 1;
+				znode = get_znode(c, znode, n);
+				if (IS_ERR(znode))
+					return znode;
+			}
+			break;
+		}
+	}
+	return znode;
+}
+
+/**
+ * right_znode - get the znode to the right.
+ * @c: UBIFS file-system description object
+ * @znode: znode
+ *
+ * This function returns a pointer to the znode to the right of @znode or NULL
+ * if there is not one. A negative error code is returned on failure.
+ */
+static struct ubifs_znode *right_znode(struct ubifs_info *c,
+				       struct ubifs_znode *znode)
+{
+	int level = znode->level;
+
+	while (1) {
+		int n = znode->iip + 1;
+
+		/* Go up until we can go right */
+		znode = znode->parent;
+		if (!znode)
+			return NULL;
+		if (n < znode->child_cnt) {
+			/* Now go down the leftmost branch to 'level' */
+			znode = get_znode(c, znode, n);
+			if (IS_ERR(znode))
+				return znode;
+			while (znode->level != level) {
+				znode = get_znode(c, znode, 0);
+				if (IS_ERR(znode))
+					return znode;
+			}
+			break;
+		}
+	}
+	return znode;
+}
+
+/**
+ * lookup_znode - find a particular indexing node from TNC.
+ * @c: UBIFS file-system description object
+ * @key: index node key to lookup
+ * @level: index node level
+ * @lnum: index node LEB number
+ * @offs: index node offset
+ *
+ * This function searches an indexing node by its first key @key and its
+ * address @lnum:@offs. It looks up the indexing tree by pulling all indexing
+ * nodes it traverses to TNC. This function is called for indexing nodes which
+ * were found on the media by scanning, for example when garbage-collecting or
+ * when doing in-the-gaps commit. This means that the indexing node which is
+ * looked for does not have to have exactly the same leftmost key @key, because
+ * the leftmost key may have been changed, in which case TNC will contain a
+ * dirty znode which still refers the same @lnum:@offs. This function is clever
+ * enough to recognize such indexing nodes.
+ *
+ * Note, if a znode was deleted or changed too much, then this function will
+ * not find it. For situations like this UBIFS has the old index RB-tree
+ * (indexed by @lnum:@offs).
+ *
+ * This function returns a pointer to the znode found or %NULL if it is not
+ * found. A negative error code is returned on failure.
+ */
+static struct ubifs_znode *lookup_znode(struct ubifs_info *c,
+					union ubifs_key *key, int level,
+					int lnum, int offs)
+{
+	struct ubifs_znode *znode, *zn;
+	int n, nn;
+
+	ubifs_assert(c, key_type(c, key) < UBIFS_INVALID_KEY);
+
+	/*
+	 * The arguments have probably been read off flash, so don't assume
+	 * they are valid.
+	 */
+	if (level < 0)
+		return ERR_PTR(-EINVAL);
+
+	/* Get the root znode */
+	znode = c->zroot.znode;
+	if (!znode) {
+		znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
+		if (IS_ERR(znode))
+			return znode;
+	}
+	/* Check if it is the one we are looking for */
+	if (c->zroot.lnum == lnum && c->zroot.offs == offs)
+		return znode;
+	/* Descend to the parent level i.e. (level + 1) */
+	if (level >= znode->level)
+		return NULL;
+	while (1) {
+		ubifs_search_zbranch(c, znode, key, &n);
+		if (n < 0) {
+			/*
+			 * We reached a znode where the leftmost key is greater
+			 * than the key we are searching for. This is the same
+			 * situation as the one described in a huge comment at
+			 * the end of the 'ubifs_lookup_level0()' function. And
+			 * for exactly the same reasons we have to try to look
+			 * left before giving up.
+			 */
+			znode = left_znode(c, znode);
+			if (!znode)
+				return NULL;
+			if (IS_ERR(znode))
+				return znode;
+			ubifs_search_zbranch(c, znode, key, &n);
+			ubifs_assert(c, n >= 0);
+		}
+		if (znode->level == level + 1)
+			break;
+		znode = get_znode(c, znode, n);
+		if (IS_ERR(znode))
+			return znode;
+	}
+	/* Check if the child is the one we are looking for */
+	if (znode->zbranch[n].lnum == lnum && znode->zbranch[n].offs == offs)
+		return get_znode(c, znode, n);
+	/* If the key is unique, there is nowhere else to look */
+	if (!is_hash_key(c, key))
+		return NULL;
+	/*
+	 * The key is not unique and so may be also in the znodes to either
+	 * side.
+	 */
+	zn = znode;
+	nn = n;
+	/* Look left */
+	while (1) {
+		/* Move one branch to the left */
+		if (n)
+			n -= 1;
+		else {
+			znode = left_znode(c, znode);
+			if (!znode)
+				break;
+			if (IS_ERR(znode))
+				return znode;
+			n = znode->child_cnt - 1;
+		}
+		/* Check it */
+		if (znode->zbranch[n].lnum == lnum &&
+		    znode->zbranch[n].offs == offs)
+			return get_znode(c, znode, n);
+		/* Stop if the key is less than the one we are looking for */
+		if (keys_cmp(c, &znode->zbranch[n].key, key) < 0)
+			break;
+	}
+	/* Back to the middle */
+	znode = zn;
+	n = nn;
+	/* Look right */
+	while (1) {
+		/* Move one branch to the right */
+		if (++n >= znode->child_cnt) {
+			znode = right_znode(c, znode);
+			if (!znode)
+				break;
+			if (IS_ERR(znode))
+				return znode;
+			n = 0;
+		}
+		/* Check it */
+		if (znode->zbranch[n].lnum == lnum &&
+		    znode->zbranch[n].offs == offs)
+			return get_znode(c, znode, n);
+		/* Stop if the key is greater than the one we are looking for */
+		if (keys_cmp(c, &znode->zbranch[n].key, key) > 0)
+			break;
+	}
+	return NULL;
+}
+
+/**
+ * is_idx_node_in_tnc - determine if an index node is in the TNC.
+ * @c: UBIFS file-system description object
+ * @key: key of index node
+ * @level: index node level
+ * @lnum: LEB number of index node
+ * @offs: offset of index node
+ *
+ * This function returns %0 if the index node is not referred to in the TNC, %1
+ * if the index node is referred to in the TNC and the corresponding znode is
+ * dirty, %2 if an index node is referred to in the TNC and the corresponding
+ * znode is clean, and a negative error code in case of failure.
+ *
+ * Note, the @key argument has to be the key of the first child. Also note,
+ * this function relies on the fact that 0:0 is never a valid LEB number and
+ * offset for a main-area node.
+ */
+int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level,
+		       int lnum, int offs)
+{
+	struct ubifs_znode *znode;
+
+	znode = lookup_znode(c, key, level, lnum, offs);
+	if (!znode)
+		return 0;
+	if (IS_ERR(znode))
+		return PTR_ERR(znode);
+
+	return ubifs_zn_dirty(znode) ? 1 : 2;
+}
+
+/**
+ * is_leaf_node_in_tnc - determine if a non-indexing not is in the TNC.
+ * @c: UBIFS file-system description object
+ * @key: node key
+ * @lnum: node LEB number
+ * @offs: node offset
+ *
+ * This function returns %1 if the node is referred to in the TNC, %0 if it is
+ * not, and a negative error code in case of failure.
+ *
+ * Note, this function relies on the fact that 0:0 is never a valid LEB number
+ * and offset for a main-area node.
+ */
+static int is_leaf_node_in_tnc(struct ubifs_info *c, union ubifs_key *key,
+			       int lnum, int offs)
+{
+	struct ubifs_zbranch *zbr;
+	struct ubifs_znode *znode, *zn;
+	int n, found, err, nn;
+	const int unique = !is_hash_key(c, key);
+
+	found = ubifs_lookup_level0(c, key, &znode, &n);
+	if (found < 0)
+		return found; /* Error code */
+	if (!found)
+		return 0;
+	zbr = &znode->zbranch[n];
+	if (lnum == zbr->lnum && offs == zbr->offs)
+		return 1; /* Found it */
+	if (unique)
+		return 0;
+	/*
+	 * Because the key is not unique, we have to look left
+	 * and right as well
+	 */
+	zn = znode;
+	nn = n;
+	/* Look left */
+	while (1) {
+		err = tnc_prev(c, &znode, &n);
+		if (err == -ENOENT)
+			break;
+		if (err)
+			return err;
+		if (keys_cmp(c, key, &znode->zbranch[n].key))
+			break;
+		zbr = &znode->zbranch[n];
+		if (lnum == zbr->lnum && offs == zbr->offs)
+			return 1; /* Found it */
+	}
+	/* Look right */
+	znode = zn;
+	n = nn;
+	while (1) {
+		err = tnc_next(c, &znode, &n);
+		if (err) {
+			if (err == -ENOENT)
+				return 0;
+			return err;
+		}
+		if (keys_cmp(c, key, &znode->zbranch[n].key))
+			break;
+		zbr = &znode->zbranch[n];
+		if (lnum == zbr->lnum && offs == zbr->offs)
+			return 1; /* Found it */
+	}
+	return 0;
+}
+
+/**
+ * ubifs_tnc_has_node - determine whether a node is in the TNC.
+ * @c: UBIFS file-system description object
+ * @key: node key
+ * @level: index node level (if it is an index node)
+ * @lnum: node LEB number
+ * @offs: node offset
+ * @is_idx: non-zero if the node is an index node
+ *
+ * This function returns %1 if the node is in the TNC, %0 if it is not, and a
+ * negative error code in case of failure. For index nodes, @key has to be the
+ * key of the first child. An index node is considered to be in the TNC only if
+ * the corresponding znode is clean or has not been loaded.
+ */
+int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level,
+		       int lnum, int offs, int is_idx)
+{
+	int err;
+
+	mutex_lock(&c->tnc_mutex);
+	if (is_idx) {
+		err = is_idx_node_in_tnc(c, key, level, lnum, offs);
+		if (err < 0)
+			goto out_unlock;
+		if (err == 1)
+			/* The index node was found but it was dirty */
+			err = 0;
+		else if (err == 2)
+			/* The index node was found and it was clean */
+			err = 1;
+		else
+			BUG_ON(err != 0);
+	} else
+		err = is_leaf_node_in_tnc(c, key, lnum, offs);
+
+out_unlock:
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * ubifs_dirty_idx_node - dirty an index node.
+ * @c: UBIFS file-system description object
+ * @key: index node key
+ * @level: index node level
+ * @lnum: index node LEB number
+ * @offs: index node offset
+ *
+ * This function loads and dirties an index node so that it can be garbage
+ * collected. The @key argument has to be the key of the first child. This
+ * function relies on the fact that 0:0 is never a valid LEB number and offset
+ * for a main-area node. Returns %0 on success and a negative error code on
+ * failure.
+ */
+int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level,
+			 int lnum, int offs)
+{
+	struct ubifs_znode *znode;
+	int err = 0;
+
+	mutex_lock(&c->tnc_mutex);
+	znode = lookup_znode(c, key, level, lnum, offs);
+	if (!znode)
+		goto out_unlock;
+	if (IS_ERR(znode)) {
+		err = PTR_ERR(znode);
+		goto out_unlock;
+	}
+	znode = dirty_cow_bottom_up(c, znode);
+	if (IS_ERR(znode)) {
+		err = PTR_ERR(znode);
+		goto out_unlock;
+	}
+
+out_unlock:
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * dbg_check_inode_size - check if inode size is correct.
+ * @c: UBIFS file-system description object
+ * @inode: inode to check
+ * @size: inode size
+ *
+ * This function makes sure that the inode size (@size) is correct and it does
+ * not have any pages beyond @size. Returns zero if the inode is OK, %-EINVAL
+ * if it has a data page beyond @size, and other negative error code in case of
+ * other errors.
+ */
+int dbg_check_inode_size(struct ubifs_info *c, const struct inode *inode,
+			 loff_t size)
+{
+	int err, n;
+	union ubifs_key from_key, to_key, *key;
+	struct ubifs_znode *znode;
+	unsigned int block;
+
+	if (!S_ISREG(inode->i_mode))
+		return 0;
+	if (!dbg_is_chk_gen(c))
+		return 0;
+
+	block = (size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT;
+	data_key_init(c, &from_key, inode->i_ino, block);
+	highest_data_key(c, &to_key, inode->i_ino);
+
+	mutex_lock(&c->tnc_mutex);
+	err = ubifs_lookup_level0(c, &from_key, &znode, &n);
+	if (err < 0)
+		goto out_unlock;
+
+	if (err) {
+		key = &from_key;
+		goto out_dump;
+	}
+
+	err = tnc_next(c, &znode, &n);
+	if (err == -ENOENT) {
+		err = 0;
+		goto out_unlock;
+	}
+	if (err < 0)
+		goto out_unlock;
+
+	ubifs_assert(c, err == 0);
+	key = &znode->zbranch[n].key;
+	if (!key_in_range(c, key, &from_key, &to_key))
+		goto out_unlock;
+
+out_dump:
+	block = key_block(c, key);
+	ubifs_err(c, "inode %lu has size %lld, but there are data at offset %lld",
+		  (unsigned long)inode->i_ino, size,
+		  ((loff_t)block) << UBIFS_BLOCK_SHIFT);
+	mutex_unlock(&c->tnc_mutex);
+	ubifs_dump_inode(c, inode);
+	dump_stack();
+	return -EINVAL;
+
+out_unlock:
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
diff --git a/ubifs-utils/libubifs/tnc_commit.c b/ubifs-utils/libubifs/tnc_commit.c
new file mode 100644
index 00000000..a55e0482
--- /dev/null
+++ b/ubifs-utils/libubifs/tnc_commit.c
@@ -0,0 +1,1111 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/* This file implements TNC functions for committing */
+
+#include <linux/random.h>
+#include "ubifs.h"
+
+/**
+ * make_idx_node - make an index node for fill-the-gaps method of TNC commit.
+ * @c: UBIFS file-system description object
+ * @idx: buffer in which to place new index node
+ * @znode: znode from which to make new index node
+ * @lnum: LEB number where new index node will be written
+ * @offs: offset where new index node will be written
+ * @len: length of new index node
+ */
+static int make_idx_node(struct ubifs_info *c, struct ubifs_idx_node *idx,
+			 struct ubifs_znode *znode, int lnum, int offs, int len)
+{
+	struct ubifs_znode *zp;
+	u8 hash[UBIFS_HASH_ARR_SZ];
+	int i, err;
+
+	/* Make index node */
+	idx->ch.node_type = UBIFS_IDX_NODE;
+	idx->child_cnt = cpu_to_le16(znode->child_cnt);
+	idx->level = cpu_to_le16(znode->level);
+	for (i = 0; i < znode->child_cnt; i++) {
+		struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
+		struct ubifs_zbranch *zbr = &znode->zbranch[i];
+
+		key_write_idx(c, &zbr->key, &br->key);
+		br->lnum = cpu_to_le32(zbr->lnum);
+		br->offs = cpu_to_le32(zbr->offs);
+		br->len = cpu_to_le32(zbr->len);
+		ubifs_copy_hash(c, zbr->hash, ubifs_branch_hash(c, br));
+		if (!zbr->lnum || !zbr->len) {
+			ubifs_err(c, "bad ref in znode");
+			ubifs_dump_znode(c, znode);
+			if (zbr->znode)
+				ubifs_dump_znode(c, zbr->znode);
+
+			return -EINVAL;
+		}
+	}
+	ubifs_prepare_node(c, idx, len, 0);
+	ubifs_node_calc_hash(c, idx, hash);
+
+	znode->lnum = lnum;
+	znode->offs = offs;
+	znode->len = len;
+
+	err = insert_old_idx_znode(c, znode);
+
+	/* Update the parent */
+	zp = znode->parent;
+	if (zp) {
+		struct ubifs_zbranch *zbr;
+
+		zbr = &zp->zbranch[znode->iip];
+		zbr->lnum = lnum;
+		zbr->offs = offs;
+		zbr->len = len;
+		ubifs_copy_hash(c, hash, zbr->hash);
+	} else {
+		c->zroot.lnum = lnum;
+		c->zroot.offs = offs;
+		c->zroot.len = len;
+		ubifs_copy_hash(c, hash, c->zroot.hash);
+	}
+	c->calc_idx_sz += ALIGN(len, 8);
+
+	atomic_long_dec(&c->dirty_zn_cnt);
+
+	ubifs_assert(c, ubifs_zn_dirty(znode));
+	ubifs_assert(c, ubifs_zn_cow(znode));
+
+	/*
+	 * Note, unlike 'write_index()' we do not add memory barriers here
+	 * because this function is called with @c->tnc_mutex locked.
+	 */
+	__clear_bit(DIRTY_ZNODE, &znode->flags);
+	__clear_bit(COW_ZNODE, &znode->flags);
+
+	return err;
+}
+
+/**
+ * fill_gap - make index nodes in gaps in dirty index LEBs.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number that gap appears in
+ * @gap_start: offset of start of gap
+ * @gap_end: offset of end of gap
+ * @dirt: adds dirty space to this
+ *
+ * This function returns the number of index nodes written into the gap.
+ */
+static int fill_gap(struct ubifs_info *c, int lnum, int gap_start, int gap_end,
+		    int *dirt)
+{
+	int len, gap_remains, gap_pos, written, pad_len;
+
+	ubifs_assert(c, (gap_start & 7) == 0);
+	ubifs_assert(c, (gap_end & 7) == 0);
+	ubifs_assert(c, gap_end >= gap_start);
+
+	gap_remains = gap_end - gap_start;
+	if (!gap_remains)
+		return 0;
+	gap_pos = gap_start;
+	written = 0;
+	while (c->enext) {
+		len = ubifs_idx_node_sz(c, c->enext->child_cnt);
+		if (len < gap_remains) {
+			struct ubifs_znode *znode = c->enext;
+			const int alen = ALIGN(len, 8);
+			int err;
+
+			ubifs_assert(c, alen <= gap_remains);
+			err = make_idx_node(c, c->ileb_buf + gap_pos, znode,
+					    lnum, gap_pos, len);
+			if (err)
+				return err;
+			gap_remains -= alen;
+			gap_pos += alen;
+			c->enext = znode->cnext;
+			if (c->enext == c->cnext)
+				c->enext = NULL;
+			written += 1;
+		} else
+			break;
+	}
+	if (gap_end == c->leb_size) {
+		c->ileb_len = ALIGN(gap_pos, c->min_io_size);
+		/* Pad to end of min_io_size */
+		pad_len = c->ileb_len - gap_pos;
+	} else
+		/* Pad to end of gap */
+		pad_len = gap_remains;
+	dbg_gc("LEB %d:%d to %d len %d nodes written %d wasted bytes %d",
+	       lnum, gap_start, gap_end, gap_end - gap_start, written, pad_len);
+	ubifs_pad(c, c->ileb_buf + gap_pos, pad_len);
+	*dirt += pad_len;
+	return written;
+}
+
+/**
+ * find_old_idx - find an index node obsoleted since the last commit start.
+ * @c: UBIFS file-system description object
+ * @lnum: LEB number of obsoleted index node
+ * @offs: offset of obsoleted index node
+ *
+ * Returns %1 if found and %0 otherwise.
+ */
+static int find_old_idx(struct ubifs_info *c, int lnum, int offs)
+{
+	struct ubifs_old_idx *o;
+	struct rb_node *p;
+
+	p = c->old_idx.rb_node;
+	while (p) {
+		o = rb_entry(p, struct ubifs_old_idx, rb);
+		if (lnum < o->lnum)
+			p = p->rb_left;
+		else if (lnum > o->lnum)
+			p = p->rb_right;
+		else if (offs < o->offs)
+			p = p->rb_left;
+		else if (offs > o->offs)
+			p = p->rb_right;
+		else
+			return 1;
+	}
+	return 0;
+}
+
+/**
+ * is_idx_node_in_use - determine if an index node can be overwritten.
+ * @c: UBIFS file-system description object
+ * @key: key of index node
+ * @level: index node level
+ * @lnum: LEB number of index node
+ * @offs: offset of index node
+ *
+ * If @key / @lnum / @offs identify an index node that was not part of the old
+ * index, then this function returns %0 (obsolete).  Else if the index node was
+ * part of the old index but is now dirty %1 is returned, else if it is clean %2
+ * is returned. A negative error code is returned on failure.
+ */
+static int is_idx_node_in_use(struct ubifs_info *c, union ubifs_key *key,
+			      int level, int lnum, int offs)
+{
+	int ret;
+
+	ret = is_idx_node_in_tnc(c, key, level, lnum, offs);
+	if (ret < 0)
+		return ret; /* Error code */
+	if (ret == 0)
+		if (find_old_idx(c, lnum, offs))
+			return 1;
+	return ret;
+}
+
+/**
+ * layout_leb_in_gaps - layout index nodes using in-the-gaps method.
+ * @c: UBIFS file-system description object
+ * @p: return LEB number in @c->gap_lebs[p]
+ *
+ * This function lays out new index nodes for dirty znodes using in-the-gaps
+ * method of TNC commit.
+ * This function merely puts the next znode into the next gap, making no attempt
+ * to try to maximise the number of znodes that fit.
+ * This function returns the number of index nodes written into the gaps, or a
+ * negative error code on failure.
+ */
+static int layout_leb_in_gaps(struct ubifs_info *c, int p)
+{
+	struct ubifs_scan_leb *sleb;
+	struct ubifs_scan_node *snod;
+	int lnum, dirt = 0, gap_start, gap_end, err, written, tot_written;
+
+	tot_written = 0;
+	/* Get an index LEB with lots of obsolete index nodes */
+	lnum = ubifs_find_dirty_idx_leb(c);
+	if (lnum < 0)
+		/*
+		 * There also may be dirt in the index head that could be
+		 * filled, however we do not check there at present.
+		 */
+		return lnum; /* Error code */
+	c->gap_lebs[p] = lnum;
+	dbg_gc("LEB %d", lnum);
+	/*
+	 * Scan the index LEB.  We use the generic scan for this even though
+	 * it is more comprehensive and less efficient than is needed for this
+	 * purpose.
+	 */
+	sleb = ubifs_scan(c, lnum, 0, c->ileb_buf, 0);
+	c->ileb_len = 0;
+	if (IS_ERR(sleb))
+		return PTR_ERR(sleb);
+	gap_start = 0;
+	list_for_each_entry(snod, &sleb->nodes, list) {
+		struct ubifs_idx_node *idx;
+		int in_use, level;
+
+		ubifs_assert(c, snod->type == UBIFS_IDX_NODE);
+		idx = snod->node;
+		key_read(c, ubifs_idx_key(c, idx), &snod->key);
+		level = le16_to_cpu(idx->level);
+		/* Determine if the index node is in use (not obsolete) */
+		in_use = is_idx_node_in_use(c, &snod->key, level, lnum,
+					    snod->offs);
+		if (in_use < 0) {
+			ubifs_scan_destroy(sleb);
+			return in_use; /* Error code */
+		}
+		if (in_use) {
+			if (in_use == 1)
+				dirt += ALIGN(snod->len, 8);
+			/*
+			 * The obsolete index nodes form gaps that can be
+			 * overwritten.  This gap has ended because we have
+			 * found an index node that is still in use
+			 * i.e. not obsolete
+			 */
+			gap_end = snod->offs;
+			/* Try to fill gap */
+			written = fill_gap(c, lnum, gap_start, gap_end, &dirt);
+			if (written < 0) {
+				ubifs_scan_destroy(sleb);
+				return written; /* Error code */
+			}
+			tot_written += written;
+			gap_start = ALIGN(snod->offs + snod->len, 8);
+		}
+	}
+	ubifs_scan_destroy(sleb);
+	c->ileb_len = c->leb_size;
+	gap_end = c->leb_size;
+	/* Try to fill gap */
+	written = fill_gap(c, lnum, gap_start, gap_end, &dirt);
+	if (written < 0)
+		return written; /* Error code */
+	tot_written += written;
+	if (tot_written == 0) {
+		struct ubifs_lprops lp;
+
+		dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written);
+		err = ubifs_read_one_lp(c, lnum, &lp);
+		if (err)
+			return err;
+		if (lp.free == c->leb_size) {
+			/*
+			 * We must have snatched this LEB from the idx_gc list
+			 * so we need to correct the free and dirty space.
+			 */
+			err = ubifs_change_one_lp(c, lnum,
+						  c->leb_size - c->ileb_len,
+						  dirt, 0, 0, 0);
+			if (err)
+				return err;
+		}
+		return 0;
+	}
+	err = ubifs_change_one_lp(c, lnum, c->leb_size - c->ileb_len, dirt,
+				  0, 0, 0);
+	if (err)
+		return err;
+	err = ubifs_leb_change(c, lnum, c->ileb_buf, c->ileb_len);
+	if (err)
+		return err;
+	dbg_gc("LEB %d wrote %d index nodes", lnum, tot_written);
+	return tot_written;
+}
+
+/**
+ * get_leb_cnt - calculate the number of empty LEBs needed to commit.
+ * @c: UBIFS file-system description object
+ * @cnt: number of znodes to commit
+ *
+ * This function returns the number of empty LEBs needed to commit @cnt znodes
+ * to the current index head.  The number is not exact and may be more than
+ * needed.
+ */
+static int get_leb_cnt(struct ubifs_info *c, int cnt)
+{
+	int d;
+
+	/* Assume maximum index node size (i.e. overestimate space needed) */
+	cnt -= (c->leb_size - c->ihead_offs) / c->max_idx_node_sz;
+	if (cnt < 0)
+		cnt = 0;
+	d = c->leb_size / c->max_idx_node_sz;
+	return DIV_ROUND_UP(cnt, d);
+}
+
+/**
+ * layout_in_gaps - in-the-gaps method of committing TNC.
+ * @c: UBIFS file-system description object
+ * @cnt: number of dirty znodes to commit.
+ *
+ * This function lays out new index nodes for dirty znodes using in-the-gaps
+ * method of TNC commit.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int layout_in_gaps(struct ubifs_info *c, int cnt)
+{
+	int err, leb_needed_cnt, written, p = 0, old_idx_lebs, *gap_lebs;
+
+	dbg_gc("%d znodes to write", cnt);
+
+	c->gap_lebs = kmalloc_array(c->lst.idx_lebs + 1, sizeof(int),
+				    GFP_NOFS);
+	if (!c->gap_lebs)
+		return -ENOMEM;
+
+	old_idx_lebs = c->lst.idx_lebs;
+	do {
+		ubifs_assert(c, p < c->lst.idx_lebs);
+		written = layout_leb_in_gaps(c, p);
+		if (written < 0) {
+			err = written;
+			if (err != -ENOSPC) {
+				kfree(c->gap_lebs);
+				c->gap_lebs = NULL;
+				return err;
+			}
+			if (!dbg_is_chk_index(c)) {
+				/*
+				 * Do not print scary warnings if the debugging
+				 * option which forces in-the-gaps is enabled.
+				 */
+				ubifs_warn(c, "out of space");
+				ubifs_dump_budg(c, &c->bi);
+				ubifs_dump_lprops(c);
+			}
+			/* Try to commit anyway */
+			break;
+		}
+		p++;
+		cnt -= written;
+		leb_needed_cnt = get_leb_cnt(c, cnt);
+		dbg_gc("%d znodes remaining, need %d LEBs, have %d", cnt,
+		       leb_needed_cnt, c->ileb_cnt);
+		/*
+		 * Dynamically change the size of @c->gap_lebs to prevent
+		 * oob, because @c->lst.idx_lebs could be increased by
+		 * function @get_idx_gc_leb (called by layout_leb_in_gaps->
+		 * ubifs_find_dirty_idx_leb) during loop. Only enlarge
+		 * @c->gap_lebs when needed.
+		 *
+		 */
+		if (leb_needed_cnt > c->ileb_cnt && p >= old_idx_lebs &&
+		    old_idx_lebs < c->lst.idx_lebs) {
+			old_idx_lebs = c->lst.idx_lebs;
+			gap_lebs = krealloc(c->gap_lebs, sizeof(int) *
+					       (old_idx_lebs + 1), GFP_NOFS);
+			if (!gap_lebs) {
+				kfree(c->gap_lebs);
+				c->gap_lebs = NULL;
+				return -ENOMEM;
+			}
+			c->gap_lebs = gap_lebs;
+		}
+	} while (leb_needed_cnt > c->ileb_cnt);
+
+	c->gap_lebs[p] = -1;
+	return 0;
+}
+
+/**
+ * layout_in_empty_space - layout index nodes in empty space.
+ * @c: UBIFS file-system description object
+ *
+ * This function lays out new index nodes for dirty znodes using empty LEBs.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int layout_in_empty_space(struct ubifs_info *c)
+{
+	struct ubifs_znode *znode, *cnext, *zp;
+	int lnum, offs, len, next_len, buf_len, buf_offs, used, avail;
+	int wlen, blen, err;
+
+	cnext = c->enext;
+	if (!cnext)
+		return 0;
+
+	lnum = c->ihead_lnum;
+	buf_offs = c->ihead_offs;
+
+	buf_len = ubifs_idx_node_sz(c, c->fanout);
+	buf_len = ALIGN(buf_len, c->min_io_size);
+	used = 0;
+	avail = buf_len;
+
+	/* Ensure there is enough room for first write */
+	next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
+	if (buf_offs + next_len > c->leb_size)
+		lnum = -1;
+
+	while (1) {
+		znode = cnext;
+
+		len = ubifs_idx_node_sz(c, znode->child_cnt);
+
+		/* Determine the index node position */
+		if (lnum == -1) {
+			if (c->ileb_nxt >= c->ileb_cnt) {
+				ubifs_err(c, "out of space");
+				return -ENOSPC;
+			}
+			lnum = c->ilebs[c->ileb_nxt++];
+			buf_offs = 0;
+			used = 0;
+			avail = buf_len;
+		}
+
+		offs = buf_offs + used;
+
+		znode->lnum = lnum;
+		znode->offs = offs;
+		znode->len = len;
+
+		/* Update the parent */
+		zp = znode->parent;
+		if (zp) {
+			struct ubifs_zbranch *zbr;
+			int i;
+
+			i = znode->iip;
+			zbr = &zp->zbranch[i];
+			zbr->lnum = lnum;
+			zbr->offs = offs;
+			zbr->len = len;
+		} else {
+			c->zroot.lnum = lnum;
+			c->zroot.offs = offs;
+			c->zroot.len = len;
+		}
+		c->calc_idx_sz += ALIGN(len, 8);
+
+		/*
+		 * Once lprops is updated, we can decrease the dirty znode count
+		 * but it is easier to just do it here.
+		 */
+		atomic_long_dec(&c->dirty_zn_cnt);
+
+		/*
+		 * Calculate the next index node length to see if there is
+		 * enough room for it
+		 */
+		cnext = znode->cnext;
+		if (cnext == c->cnext)
+			next_len = 0;
+		else
+			next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
+
+		/* Update buffer positions */
+		wlen = used + len;
+		used += ALIGN(len, 8);
+		avail -= ALIGN(len, 8);
+
+		if (next_len != 0 &&
+		    buf_offs + used + next_len <= c->leb_size &&
+		    avail > 0)
+			continue;
+
+		if (avail <= 0 && next_len &&
+		    buf_offs + used + next_len <= c->leb_size)
+			blen = buf_len;
+		else
+			blen = ALIGN(wlen, c->min_io_size);
+
+		/* The buffer is full or there are no more znodes to do */
+		buf_offs += blen;
+		if (next_len) {
+			if (buf_offs + next_len > c->leb_size) {
+				err = ubifs_update_one_lp(c, lnum,
+					c->leb_size - buf_offs, blen - used,
+					0, 0);
+				if (err)
+					return err;
+				lnum = -1;
+			}
+			used -= blen;
+			if (used < 0)
+				used = 0;
+			avail = buf_len - used;
+			continue;
+		}
+		err = ubifs_update_one_lp(c, lnum, c->leb_size - buf_offs,
+					  blen - used, 0, 0);
+		if (err)
+			return err;
+		break;
+	}
+
+	c->dbg->new_ihead_lnum = lnum;
+	c->dbg->new_ihead_offs = buf_offs;
+
+	return 0;
+}
+
+/**
+ * layout_commit - determine positions of index nodes to commit.
+ * @c: UBIFS file-system description object
+ * @no_space: indicates that insufficient empty LEBs were allocated
+ * @cnt: number of znodes to commit
+ *
+ * Calculate and update the positions of index nodes to commit.  If there were
+ * an insufficient number of empty LEBs allocated, then index nodes are placed
+ * into the gaps created by obsolete index nodes in non-empty index LEBs.  For
+ * this purpose, an obsolete index node is one that was not in the index as at
+ * the end of the last commit.  To write "in-the-gaps" requires that those index
+ * LEBs are updated atomically in-place.
+ */
+static int layout_commit(struct ubifs_info *c, int no_space, int cnt)
+{
+	int err;
+
+	if (no_space) {
+		err = layout_in_gaps(c, cnt);
+		if (err)
+			return err;
+	}
+	err = layout_in_empty_space(c);
+	return err;
+}
+
+/**
+ * find_first_dirty - find first dirty znode.
+ * @znode: znode to begin searching from
+ */
+static struct ubifs_znode *find_first_dirty(struct ubifs_znode *znode)
+{
+	int i, cont;
+
+	if (!znode)
+		return NULL;
+
+	while (1) {
+		if (znode->level == 0) {
+			if (ubifs_zn_dirty(znode))
+				return znode;
+			return NULL;
+		}
+		cont = 0;
+		for (i = 0; i < znode->child_cnt; i++) {
+			struct ubifs_zbranch *zbr = &znode->zbranch[i];
+
+			if (zbr->znode && ubifs_zn_dirty(zbr->znode)) {
+				znode = zbr->znode;
+				cont = 1;
+				break;
+			}
+		}
+		if (!cont) {
+			if (ubifs_zn_dirty(znode))
+				return znode;
+			return NULL;
+		}
+	}
+}
+
+/**
+ * find_next_dirty - find next dirty znode.
+ * @znode: znode to begin searching from
+ */
+static struct ubifs_znode *find_next_dirty(struct ubifs_znode *znode)
+{
+	int n = znode->iip + 1;
+
+	znode = znode->parent;
+	if (!znode)
+		return NULL;
+	for (; n < znode->child_cnt; n++) {
+		struct ubifs_zbranch *zbr = &znode->zbranch[n];
+
+		if (zbr->znode && ubifs_zn_dirty(zbr->znode))
+			return find_first_dirty(zbr->znode);
+	}
+	return znode;
+}
+
+/**
+ * get_znodes_to_commit - create list of dirty znodes to commit.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns the number of znodes to commit.
+ */
+static int get_znodes_to_commit(struct ubifs_info *c)
+{
+	struct ubifs_znode *znode, *cnext;
+	int cnt = 0;
+
+	c->cnext = find_first_dirty(c->zroot.znode);
+	znode = c->enext = c->cnext;
+	if (!znode) {
+		dbg_cmt("no znodes to commit");
+		return 0;
+	}
+	cnt += 1;
+	while (1) {
+		ubifs_assert(c, !ubifs_zn_cow(znode));
+		__set_bit(COW_ZNODE, &znode->flags);
+		znode->alt = 0;
+		cnext = find_next_dirty(znode);
+		if (!cnext) {
+			znode->cnext = c->cnext;
+			break;
+		}
+		znode->cparent = znode->parent;
+		znode->ciip = znode->iip;
+		znode->cnext = cnext;
+		znode = cnext;
+		cnt += 1;
+	}
+	dbg_cmt("committing %d znodes", cnt);
+	ubifs_assert(c, cnt == atomic_long_read(&c->dirty_zn_cnt));
+	return cnt;
+}
+
+/**
+ * alloc_idx_lebs - allocate empty LEBs to be used to commit.
+ * @c: UBIFS file-system description object
+ * @cnt: number of znodes to commit
+ *
+ * This function returns %-ENOSPC if it cannot allocate a sufficient number of
+ * empty LEBs.  %0 is returned on success, otherwise a negative error code
+ * is returned.
+ */
+static int alloc_idx_lebs(struct ubifs_info *c, int cnt)
+{
+	int i, leb_cnt, lnum;
+
+	c->ileb_cnt = 0;
+	c->ileb_nxt = 0;
+	leb_cnt = get_leb_cnt(c, cnt);
+	dbg_cmt("need about %d empty LEBS for TNC commit", leb_cnt);
+	if (!leb_cnt)
+		return 0;
+	c->ilebs = kmalloc_array(leb_cnt, sizeof(int), GFP_NOFS);
+	if (!c->ilebs)
+		return -ENOMEM;
+	for (i = 0; i < leb_cnt; i++) {
+		lnum = ubifs_find_free_leb_for_idx(c);
+		if (lnum < 0)
+			return lnum;
+		c->ilebs[c->ileb_cnt++] = lnum;
+		dbg_cmt("LEB %d", lnum);
+	}
+	if (dbg_is_chk_index(c) && !get_random_u32_below(8))
+		return -ENOSPC;
+	return 0;
+}
+
+/**
+ * free_unused_idx_lebs - free unused LEBs that were allocated for the commit.
+ * @c: UBIFS file-system description object
+ *
+ * It is possible that we allocate more empty LEBs for the commit than we need.
+ * This functions frees the surplus.
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int free_unused_idx_lebs(struct ubifs_info *c)
+{
+	int i, err = 0, lnum, er;
+
+	for (i = c->ileb_nxt; i < c->ileb_cnt; i++) {
+		lnum = c->ilebs[i];
+		dbg_cmt("LEB %d", lnum);
+		er = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
+					 LPROPS_INDEX | LPROPS_TAKEN, 0);
+		if (!err)
+			err = er;
+	}
+	return err;
+}
+
+/**
+ * free_idx_lebs - free unused LEBs after commit end.
+ * @c: UBIFS file-system description object
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int free_idx_lebs(struct ubifs_info *c)
+{
+	int err;
+
+	err = free_unused_idx_lebs(c);
+	kfree(c->ilebs);
+	c->ilebs = NULL;
+	return err;
+}
+
+/**
+ * ubifs_tnc_start_commit - start TNC commit.
+ * @c: UBIFS file-system description object
+ * @zroot: new index root position is returned here
+ *
+ * This function prepares the list of indexing nodes to commit and lays out
+ * their positions on flash. If there is not enough free space it uses the
+ * in-gap commit method. Returns zero in case of success and a negative error
+ * code in case of failure.
+ */
+int ubifs_tnc_start_commit(struct ubifs_info *c, struct ubifs_zbranch *zroot)
+{
+	int err = 0, cnt;
+
+	mutex_lock(&c->tnc_mutex);
+	err = dbg_check_tnc(c, 1);
+	if (err)
+		goto out;
+	cnt = get_znodes_to_commit(c);
+	if (cnt != 0) {
+		int no_space = 0;
+
+		err = alloc_idx_lebs(c, cnt);
+		if (err == -ENOSPC)
+			no_space = 1;
+		else if (err)
+			goto out_free;
+		err = layout_commit(c, no_space, cnt);
+		if (err)
+			goto out_free;
+		ubifs_assert(c, atomic_long_read(&c->dirty_zn_cnt) == 0);
+		err = free_unused_idx_lebs(c);
+		if (err)
+			goto out;
+	}
+	destroy_old_idx(c);
+	memcpy(zroot, &c->zroot, sizeof(struct ubifs_zbranch));
+
+	err = ubifs_save_dirty_idx_lnums(c);
+	if (err)
+		goto out;
+
+	spin_lock(&c->space_lock);
+	/*
+	 * Although we have not finished committing yet, update size of the
+	 * committed index ('c->bi.old_idx_sz') and zero out the index growth
+	 * budget. It is OK to do this now, because we've reserved all the
+	 * space which is needed to commit the index, and it is save for the
+	 * budgeting subsystem to assume the index is already committed,
+	 * even though it is not.
+	 */
+	ubifs_assert(c, c->bi.min_idx_lebs == ubifs_calc_min_idx_lebs(c));
+	c->bi.old_idx_sz = c->calc_idx_sz;
+	c->bi.uncommitted_idx = 0;
+	c->bi.min_idx_lebs = ubifs_calc_min_idx_lebs(c);
+	spin_unlock(&c->space_lock);
+	mutex_unlock(&c->tnc_mutex);
+
+	dbg_cmt("number of index LEBs %d", c->lst.idx_lebs);
+	dbg_cmt("size of index %llu", c->calc_idx_sz);
+	return err;
+
+out_free:
+	free_idx_lebs(c);
+out:
+	mutex_unlock(&c->tnc_mutex);
+	return err;
+}
+
+/**
+ * write_index - write index nodes.
+ * @c: UBIFS file-system description object
+ *
+ * This function writes the index nodes whose positions were laid out in the
+ * layout_in_empty_space function.
+ */
+static int write_index(struct ubifs_info *c)
+{
+	struct ubifs_idx_node *idx;
+	struct ubifs_znode *znode, *cnext;
+	int i, lnum, offs, len, next_len, buf_len, buf_offs, used;
+	int avail, wlen, err, lnum_pos = 0, blen, nxt_offs;
+
+	cnext = c->enext;
+	if (!cnext)
+		return 0;
+
+	/*
+	 * Always write index nodes to the index head so that index nodes and
+	 * other types of nodes are never mixed in the same erase block.
+	 */
+	lnum = c->ihead_lnum;
+	buf_offs = c->ihead_offs;
+
+	/* Allocate commit buffer */
+	buf_len = ALIGN(c->max_idx_node_sz, c->min_io_size);
+	used = 0;
+	avail = buf_len;
+
+	/* Ensure there is enough room for first write */
+	next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
+	if (buf_offs + next_len > c->leb_size) {
+		err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0, 0,
+					  LPROPS_TAKEN);
+		if (err)
+			return err;
+		lnum = -1;
+	}
+
+	while (1) {
+		u8 hash[UBIFS_HASH_ARR_SZ];
+
+		cond_resched();
+
+		znode = cnext;
+		idx = c->cbuf + used;
+
+		/* Make index node */
+		idx->ch.node_type = UBIFS_IDX_NODE;
+		idx->child_cnt = cpu_to_le16(znode->child_cnt);
+		idx->level = cpu_to_le16(znode->level);
+		for (i = 0; i < znode->child_cnt; i++) {
+			struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
+			struct ubifs_zbranch *zbr = &znode->zbranch[i];
+
+			key_write_idx(c, &zbr->key, &br->key);
+			br->lnum = cpu_to_le32(zbr->lnum);
+			br->offs = cpu_to_le32(zbr->offs);
+			br->len = cpu_to_le32(zbr->len);
+			ubifs_copy_hash(c, zbr->hash, ubifs_branch_hash(c, br));
+			if (!zbr->lnum || !zbr->len) {
+				ubifs_err(c, "bad ref in znode");
+				ubifs_dump_znode(c, znode);
+				if (zbr->znode)
+					ubifs_dump_znode(c, zbr->znode);
+
+				return -EINVAL;
+			}
+		}
+		len = ubifs_idx_node_sz(c, znode->child_cnt);
+		ubifs_prepare_node(c, idx, len, 0);
+		ubifs_node_calc_hash(c, idx, hash);
+
+		mutex_lock(&c->tnc_mutex);
+
+		if (znode->cparent)
+			ubifs_copy_hash(c, hash,
+					znode->cparent->zbranch[znode->ciip].hash);
+
+		if (znode->parent) {
+			if (!ubifs_zn_obsolete(znode))
+				ubifs_copy_hash(c, hash,
+					znode->parent->zbranch[znode->iip].hash);
+		} else {
+			ubifs_copy_hash(c, hash, c->zroot.hash);
+		}
+
+		mutex_unlock(&c->tnc_mutex);
+
+		/* Determine the index node position */
+		if (lnum == -1) {
+			lnum = c->ilebs[lnum_pos++];
+			buf_offs = 0;
+			used = 0;
+			avail = buf_len;
+		}
+		offs = buf_offs + used;
+
+		if (lnum != znode->lnum || offs != znode->offs ||
+		    len != znode->len) {
+			ubifs_err(c, "inconsistent znode posn");
+			return -EINVAL;
+		}
+
+		/* Grab some stuff from znode while we still can */
+		cnext = znode->cnext;
+
+		ubifs_assert(c, ubifs_zn_dirty(znode));
+		ubifs_assert(c, ubifs_zn_cow(znode));
+
+		/*
+		 * It is important that other threads should see %DIRTY_ZNODE
+		 * flag cleared before %COW_ZNODE. Specifically, it matters in
+		 * the 'dirty_cow_znode()' function. This is the reason for the
+		 * first barrier. Also, we want the bit changes to be seen to
+		 * other threads ASAP, to avoid unnecessary copying, which is
+		 * the reason for the second barrier.
+		 */
+		clear_bit(DIRTY_ZNODE, &znode->flags);
+		smp_mb__before_atomic();
+		clear_bit(COW_ZNODE, &znode->flags);
+		smp_mb__after_atomic();
+
+		/*
+		 * We have marked the znode as clean but have not updated the
+		 * @c->clean_zn_cnt counter. If this znode becomes dirty again
+		 * before 'free_obsolete_znodes()' is called, then
+		 * @c->clean_zn_cnt will be decremented before it gets
+		 * incremented (resulting in 2 decrements for the same znode).
+		 * This means that @c->clean_zn_cnt may become negative for a
+		 * while.
+		 *
+		 * Q: why we cannot increment @c->clean_zn_cnt?
+		 * A: because we do not have the @c->tnc_mutex locked, and the
+		 *    following code would be racy and buggy:
+		 *
+		 *    if (!ubifs_zn_obsolete(znode)) {
+		 *            atomic_long_inc(&c->clean_zn_cnt);
+		 *            atomic_long_inc(&ubifs_clean_zn_cnt);
+		 *    }
+		 *
+		 *    Thus, we just delay the @c->clean_zn_cnt update until we
+		 *    have the mutex locked.
+		 */
+
+		/* Do not access znode from this point on */
+
+		/* Update buffer positions */
+		wlen = used + len;
+		used += ALIGN(len, 8);
+		avail -= ALIGN(len, 8);
+
+		/*
+		 * Calculate the next index node length to see if there is
+		 * enough room for it
+		 */
+		if (cnext == c->cnext)
+			next_len = 0;
+		else
+			next_len = ubifs_idx_node_sz(c, cnext->child_cnt);
+
+		nxt_offs = buf_offs + used + next_len;
+		if (next_len && nxt_offs <= c->leb_size) {
+			if (avail > 0)
+				continue;
+			else
+				blen = buf_len;
+		} else {
+			wlen = ALIGN(wlen, 8);
+			blen = ALIGN(wlen, c->min_io_size);
+			ubifs_pad(c, c->cbuf + wlen, blen - wlen);
+		}
+
+		/* The buffer is full or there are no more znodes to do */
+		err = ubifs_leb_write(c, lnum, c->cbuf, buf_offs, blen);
+		if (err)
+			return err;
+		buf_offs += blen;
+		if (next_len) {
+			if (nxt_offs > c->leb_size) {
+				err = ubifs_update_one_lp(c, lnum, LPROPS_NC, 0,
+							  0, LPROPS_TAKEN);
+				if (err)
+					return err;
+				lnum = -1;
+			}
+			used -= blen;
+			if (used < 0)
+				used = 0;
+			avail = buf_len - used;
+			memmove(c->cbuf, c->cbuf + blen, used);
+			continue;
+		}
+		break;
+	}
+
+	if (lnum != c->dbg->new_ihead_lnum ||
+	    buf_offs != c->dbg->new_ihead_offs) {
+		ubifs_err(c, "inconsistent ihead");
+		return -EINVAL;
+	}
+
+	c->ihead_lnum = lnum;
+	c->ihead_offs = buf_offs;
+
+	return 0;
+}
+
+/**
+ * free_obsolete_znodes - free obsolete znodes.
+ * @c: UBIFS file-system description object
+ *
+ * At the end of commit end, obsolete znodes are freed.
+ */
+static void free_obsolete_znodes(struct ubifs_info *c)
+{
+	struct ubifs_znode *znode, *cnext;
+
+	cnext = c->cnext;
+	do {
+		znode = cnext;
+		cnext = znode->cnext;
+		if (ubifs_zn_obsolete(znode))
+			kfree(znode);
+		else {
+			znode->cnext = NULL;
+			atomic_long_inc(&c->clean_zn_cnt);
+			atomic_long_inc(&ubifs_clean_zn_cnt);
+		}
+	} while (cnext != c->cnext);
+}
+
+/**
+ * return_gap_lebs - return LEBs used by the in-gap commit method.
+ * @c: UBIFS file-system description object
+ *
+ * This function clears the "taken" flag for the LEBs which were used by the
+ * "commit in-the-gaps" method.
+ */
+static int return_gap_lebs(struct ubifs_info *c)
+{
+	int *p, err;
+
+	if (!c->gap_lebs)
+		return 0;
+
+	dbg_cmt("");
+	for (p = c->gap_lebs; *p != -1; p++) {
+		err = ubifs_change_one_lp(c, *p, LPROPS_NC, LPROPS_NC, 0,
+					  LPROPS_TAKEN, 0);
+		if (err)
+			return err;
+	}
+
+	kfree(c->gap_lebs);
+	c->gap_lebs = NULL;
+	return 0;
+}
+
+/**
+ * ubifs_tnc_end_commit - update the TNC for commit end.
+ * @c: UBIFS file-system description object
+ *
+ * Write the dirty znodes.
+ */
+int ubifs_tnc_end_commit(struct ubifs_info *c)
+{
+	int err;
+
+	if (!c->cnext)
+		return 0;
+
+	err = return_gap_lebs(c);
+	if (err)
+		return err;
+
+	err = write_index(c);
+	if (err)
+		return err;
+
+	mutex_lock(&c->tnc_mutex);
+
+	dbg_cmt("TNC height is %d", c->zroot.znode->level + 1);
+
+	free_obsolete_znodes(c);
+
+	c->cnext = NULL;
+	kfree(c->ilebs);
+	c->ilebs = NULL;
+
+	mutex_unlock(&c->tnc_mutex);
+
+	return 0;
+}
diff --git a/ubifs-utils/libubifs/tnc_misc.c b/ubifs-utils/libubifs/tnc_misc.c
new file mode 100644
index 00000000..d3f8a6aa
--- /dev/null
+++ b/ubifs-utils/libubifs/tnc_misc.c
@@ -0,0 +1,524 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation.
+ *
+ * Authors: Adrian Hunter
+ *          Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/*
+ * This file contains miscelanious TNC-related functions shared betweend
+ * different files. This file does not form any logically separate TNC
+ * sub-system. The file was created because there is a lot of TNC code and
+ * putting it all in one file would make that file too big and unreadable.
+ */
+
+#include "ubifs.h"
+
+/**
+ * ubifs_tnc_levelorder_next - next TNC tree element in levelorder traversal.
+ * @c: UBIFS file-system description object
+ * @zr: root of the subtree to traverse
+ * @znode: previous znode
+ *
+ * This function implements levelorder TNC traversal. The LNC is ignored.
+ * Returns the next element or %NULL if @znode is already the last one.
+ */
+struct ubifs_znode *ubifs_tnc_levelorder_next(const struct ubifs_info *c,
+					      struct ubifs_znode *zr,
+					      struct ubifs_znode *znode)
+{
+	int level, iip, level_search = 0;
+	struct ubifs_znode *zn;
+
+	ubifs_assert(c, zr);
+
+	if (unlikely(!znode))
+		return zr;
+
+	if (unlikely(znode == zr)) {
+		if (znode->level == 0)
+			return NULL;
+		return ubifs_tnc_find_child(zr, 0);
+	}
+
+	level = znode->level;
+
+	iip = znode->iip;
+	while (1) {
+		ubifs_assert(c, znode->level <= zr->level);
+
+		/*
+		 * First walk up until there is a znode with next branch to
+		 * look at.
+		 */
+		while (znode->parent != zr && iip >= znode->parent->child_cnt) {
+			znode = znode->parent;
+			iip = znode->iip;
+		}
+
+		if (unlikely(znode->parent == zr &&
+			     iip >= znode->parent->child_cnt)) {
+			/* This level is done, switch to the lower one */
+			level -= 1;
+			if (level_search || level < 0)
+				/*
+				 * We were already looking for znode at lower
+				 * level ('level_search'). As we are here
+				 * again, it just does not exist. Or all levels
+				 * were finished ('level < 0').
+				 */
+				return NULL;
+
+			level_search = 1;
+			iip = -1;
+			znode = ubifs_tnc_find_child(zr, 0);
+			ubifs_assert(c, znode);
+		}
+
+		/* Switch to the next index */
+		zn = ubifs_tnc_find_child(znode->parent, iip + 1);
+		if (!zn) {
+			/* No more children to look at, we have walk up */
+			iip = znode->parent->child_cnt;
+			continue;
+		}
+
+		/* Walk back down to the level we came from ('level') */
+		while (zn->level != level) {
+			znode = zn;
+			zn = ubifs_tnc_find_child(zn, 0);
+			if (!zn) {
+				/*
+				 * This path is not too deep so it does not
+				 * reach 'level'. Try next path.
+				 */
+				iip = znode->iip;
+				break;
+			}
+		}
+
+		if (zn) {
+			ubifs_assert(c, zn->level >= 0);
+			return zn;
+		}
+	}
+}
+
+/**
+ * ubifs_search_zbranch - search znode branch.
+ * @c: UBIFS file-system description object
+ * @znode: znode to search in
+ * @key: key to search for
+ * @n: znode branch slot number is returned here
+ *
+ * This is a helper function which search branch with key @key in @znode using
+ * binary search. The result of the search may be:
+ *   o exact match, then %1 is returned, and the slot number of the branch is
+ *     stored in @n;
+ *   o no exact match, then %0 is returned and the slot number of the left
+ *     closest branch is returned in @n; the slot if all keys in this znode are
+ *     greater than @key, then %-1 is returned in @n.
+ */
+int ubifs_search_zbranch(const struct ubifs_info *c,
+			 const struct ubifs_znode *znode,
+			 const union ubifs_key *key, int *n)
+{
+	int beg = 0, end = znode->child_cnt, mid;
+	int cmp;
+	const struct ubifs_zbranch *zbr = &znode->zbranch[0];
+
+	ubifs_assert(c, end > beg);
+
+	while (end > beg) {
+		mid = (beg + end) >> 1;
+		cmp = keys_cmp(c, key, &zbr[mid].key);
+		if (cmp > 0)
+			beg = mid + 1;
+		else if (cmp < 0)
+			end = mid;
+		else {
+			*n = mid;
+			return 1;
+		}
+	}
+
+	*n = end - 1;
+
+	/* The insert point is after *n */
+	ubifs_assert(c, *n >= -1 && *n < znode->child_cnt);
+	if (*n == -1)
+		ubifs_assert(c, keys_cmp(c, key, &zbr[0].key) < 0);
+	else
+		ubifs_assert(c, keys_cmp(c, key, &zbr[*n].key) > 0);
+	if (*n + 1 < znode->child_cnt)
+		ubifs_assert(c, keys_cmp(c, key, &zbr[*n + 1].key) < 0);
+
+	return 0;
+}
+
+/**
+ * ubifs_tnc_postorder_first - find first znode to do postorder tree traversal.
+ * @znode: znode to start at (root of the sub-tree to traverse)
+ *
+ * Find the lowest leftmost znode in a subtree of the TNC tree. The LNC is
+ * ignored.
+ */
+struct ubifs_znode *ubifs_tnc_postorder_first(struct ubifs_znode *znode)
+{
+	if (unlikely(!znode))
+		return NULL;
+
+	while (znode->level > 0) {
+		struct ubifs_znode *child;
+
+		child = ubifs_tnc_find_child(znode, 0);
+		if (!child)
+			return znode;
+		znode = child;
+	}
+
+	return znode;
+}
+
+/**
+ * ubifs_tnc_postorder_next - next TNC tree element in postorder traversal.
+ * @c: UBIFS file-system description object
+ * @znode: previous znode
+ *
+ * This function implements postorder TNC traversal. The LNC is ignored.
+ * Returns the next element or %NULL if @znode is already the last one.
+ */
+struct ubifs_znode *ubifs_tnc_postorder_next(const struct ubifs_info *c,
+					     struct ubifs_znode *znode)
+{
+	struct ubifs_znode *zn;
+
+	ubifs_assert(c, znode);
+	if (unlikely(!znode->parent))
+		return NULL;
+
+	/* Switch to the next index in the parent */
+	zn = ubifs_tnc_find_child(znode->parent, znode->iip + 1);
+	if (!zn)
+		/* This is in fact the last child, return parent */
+		return znode->parent;
+
+	/* Go to the first znode in this new subtree */
+	return ubifs_tnc_postorder_first(zn);
+}
+
+/**
+ * ubifs_destroy_tnc_subtree - destroy all znodes connected to a subtree.
+ * @c: UBIFS file-system description object
+ * @znode: znode defining subtree to destroy
+ *
+ * This function destroys subtree of the TNC tree. Returns number of clean
+ * znodes in the subtree.
+ */
+long ubifs_destroy_tnc_subtree(const struct ubifs_info *c,
+			       struct ubifs_znode *znode)
+{
+	struct ubifs_znode *zn = ubifs_tnc_postorder_first(znode);
+	long clean_freed = 0;
+	int n;
+
+	ubifs_assert(c, zn);
+	while (1) {
+		for (n = 0; n < zn->child_cnt; n++) {
+			if (!zn->zbranch[n].znode)
+				continue;
+
+			if (zn->level > 0 &&
+			    !ubifs_zn_dirty(zn->zbranch[n].znode))
+				clean_freed += 1;
+
+			cond_resched();
+			kfree(zn->zbranch[n].znode);
+		}
+
+		if (zn == znode) {
+			if (!ubifs_zn_dirty(zn))
+				clean_freed += 1;
+			kfree(zn);
+			return clean_freed;
+		}
+
+		zn = ubifs_tnc_postorder_next(c, zn);
+	}
+}
+
+/**
+ * ubifs_destroy_tnc_tree - destroy all znodes connected to the TNC tree.
+ * @c: UBIFS file-system description object
+ *
+ * This function destroys the whole TNC tree and updates clean global znode
+ * count.
+ */
+void ubifs_destroy_tnc_tree(struct ubifs_info *c)
+{
+	long n, freed;
+
+	if (!c->zroot.znode)
+		return;
+
+	n = atomic_long_read(&c->clean_zn_cnt);
+	freed = ubifs_destroy_tnc_subtree(c, c->zroot.znode);
+	ubifs_assert(c, freed == n);
+	atomic_long_sub(n, &ubifs_clean_zn_cnt);
+
+	c->zroot.znode = NULL;
+}
+
+/**
+ * read_znode - read an indexing node from flash and fill znode.
+ * @c: UBIFS file-system description object
+ * @zzbr: the zbranch describing the node to read
+ * @znode: znode to read to
+ *
+ * This function reads an indexing node from the flash media and fills znode
+ * with the read data. Returns zero in case of success and a negative error
+ * code in case of failure. The read indexing node is validated and if anything
+ * is wrong with it, this function prints complaint messages and returns
+ * %-EINVAL.
+ */
+static int read_znode(struct ubifs_info *c, struct ubifs_zbranch *zzbr,
+		      struct ubifs_znode *znode)
+{
+	int lnum = zzbr->lnum;
+	int offs = zzbr->offs;
+	int len = zzbr->len;
+	int i, err, type, cmp;
+	struct ubifs_idx_node *idx;
+
+	idx = kmalloc(c->max_idx_node_sz, GFP_NOFS);
+	if (!idx)
+		return -ENOMEM;
+
+	err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs);
+	if (err < 0) {
+		kfree(idx);
+		return err;
+	}
+
+	err = ubifs_node_check_hash(c, idx, zzbr->hash);
+	if (err) {
+		ubifs_bad_hash(c, idx, zzbr->hash, lnum, offs);
+		kfree(idx);
+		return err;
+	}
+
+	znode->child_cnt = le16_to_cpu(idx->child_cnt);
+	znode->level = le16_to_cpu(idx->level);
+
+	dbg_tnc("LEB %d:%d, level %d, %d branch",
+		lnum, offs, znode->level, znode->child_cnt);
+
+	if (znode->child_cnt > c->fanout || znode->level > UBIFS_MAX_LEVELS) {
+		ubifs_err(c, "current fanout %d, branch count %d",
+			  c->fanout, znode->child_cnt);
+		ubifs_err(c, "max levels %d, znode level %d",
+			  UBIFS_MAX_LEVELS, znode->level);
+		err = 1;
+		goto out_dump;
+	}
+
+	for (i = 0; i < znode->child_cnt; i++) {
+		struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);
+		struct ubifs_zbranch *zbr = &znode->zbranch[i];
+
+		key_read(c, &br->key, &zbr->key);
+		zbr->lnum = le32_to_cpu(br->lnum);
+		zbr->offs = le32_to_cpu(br->offs);
+		zbr->len  = le32_to_cpu(br->len);
+		ubifs_copy_hash(c, ubifs_branch_hash(c, br), zbr->hash);
+		zbr->znode = NULL;
+
+		/* Validate branch */
+
+		if (zbr->lnum < c->main_first ||
+		    zbr->lnum >= c->leb_cnt || zbr->offs < 0 ||
+		    zbr->offs + zbr->len > c->leb_size || zbr->offs & 7) {
+			ubifs_err(c, "bad branch %d", i);
+			err = 2;
+			goto out_dump;
+		}
+
+		switch (key_type(c, &zbr->key)) {
+		case UBIFS_INO_KEY:
+		case UBIFS_DATA_KEY:
+		case UBIFS_DENT_KEY:
+		case UBIFS_XENT_KEY:
+			break;
+		default:
+			ubifs_err(c, "bad key type at slot %d: %d",
+				  i, key_type(c, &zbr->key));
+			err = 3;
+			goto out_dump;
+		}
+
+		if (znode->level)
+			continue;
+
+		type = key_type(c, &zbr->key);
+		if (c->ranges[type].max_len == 0) {
+			if (zbr->len != c->ranges[type].len) {
+				ubifs_err(c, "bad target node (type %d) length (%d)",
+					  type, zbr->len);
+				ubifs_err(c, "have to be %d", c->ranges[type].len);
+				err = 4;
+				goto out_dump;
+			}
+		} else if (zbr->len < c->ranges[type].min_len ||
+			   zbr->len > c->ranges[type].max_len) {
+			ubifs_err(c, "bad target node (type %d) length (%d)",
+				  type, zbr->len);
+			ubifs_err(c, "have to be in range of %d-%d",
+				  c->ranges[type].min_len,
+				  c->ranges[type].max_len);
+			err = 5;
+			goto out_dump;
+		}
+	}
+
+	/*
+	 * Ensure that the next key is greater or equivalent to the
+	 * previous one.
+	 */
+	for (i = 0; i < znode->child_cnt - 1; i++) {
+		const union ubifs_key *key1, *key2;
+
+		key1 = &znode->zbranch[i].key;
+		key2 = &znode->zbranch[i + 1].key;
+
+		cmp = keys_cmp(c, key1, key2);
+		if (cmp > 0) {
+			ubifs_err(c, "bad key order (keys %d and %d)", i, i + 1);
+			err = 6;
+			goto out_dump;
+		} else if (cmp == 0 && !is_hash_key(c, key1)) {
+			/* These can only be keys with colliding hash */
+			ubifs_err(c, "keys %d and %d are not hashed but equivalent",
+				  i, i + 1);
+			err = 7;
+			goto out_dump;
+		}
+	}
+
+	kfree(idx);
+	return 0;
+
+out_dump:
+	ubifs_err(c, "bad indexing node at LEB %d:%d, error %d", lnum, offs, err);
+	ubifs_dump_node(c, idx, c->max_idx_node_sz);
+	kfree(idx);
+	return -EINVAL;
+}
+
+/**
+ * ubifs_load_znode - load znode to TNC cache.
+ * @c: UBIFS file-system description object
+ * @zbr: znode branch
+ * @parent: znode's parent
+ * @iip: index in parent
+ *
+ * This function loads znode pointed to by @zbr into the TNC cache and
+ * returns pointer to it in case of success and a negative error code in case
+ * of failure.
+ */
+struct ubifs_znode *ubifs_load_znode(struct ubifs_info *c,
+				     struct ubifs_zbranch *zbr,
+				     struct ubifs_znode *parent, int iip)
+{
+	int err;
+	struct ubifs_znode *znode;
+
+	ubifs_assert(c, !zbr->znode);
+	/*
+	 * A slab cache is not presently used for znodes because the znode size
+	 * depends on the fanout which is stored in the superblock.
+	 */
+	znode = kzalloc(c->max_znode_sz, GFP_NOFS);
+	if (!znode)
+		return ERR_PTR(-ENOMEM);
+
+	err = read_znode(c, zbr, znode);
+	if (err)
+		goto out;
+
+	atomic_long_inc(&c->clean_zn_cnt);
+
+	/*
+	 * Increment the global clean znode counter as well. It is OK that
+	 * global and per-FS clean znode counters may be inconsistent for some
+	 * short time (because we might be preempted at this point), the global
+	 * one is only used in shrinker.
+	 */
+	atomic_long_inc(&ubifs_clean_zn_cnt);
+
+	zbr->znode = znode;
+	znode->parent = parent;
+	znode->time = ktime_get_seconds();
+	znode->iip = iip;
+
+	return znode;
+
+out:
+	kfree(znode);
+	return ERR_PTR(err);
+}
+
+/**
+ * ubifs_tnc_read_node - read a leaf node from the flash media.
+ * @c: UBIFS file-system description object
+ * @zbr: key and position of the node
+ * @node: node is returned here
+ *
+ * This function reads a node defined by @zbr from the flash media. Returns
+ * zero in case of success or a negative error code in case of failure.
+ */
+int ubifs_tnc_read_node(struct ubifs_info *c, struct ubifs_zbranch *zbr,
+			void *node)
+{
+	union ubifs_key key1, *key = &zbr->key;
+	int err, type = key_type(c, key);
+	struct ubifs_wbuf *wbuf;
+
+	/*
+	 * 'zbr' has to point to on-flash node. The node may sit in a bud and
+	 * may even be in a write buffer, so we have to take care about this.
+	 */
+	wbuf = ubifs_get_wbuf(c, zbr->lnum);
+	if (wbuf)
+		err = ubifs_read_node_wbuf(wbuf, node, type, zbr->len,
+					   zbr->lnum, zbr->offs);
+	else
+		err = ubifs_read_node(c, node, type, zbr->len, zbr->lnum,
+				      zbr->offs);
+
+	if (err) {
+		dbg_tnck(key, "key ");
+		return err;
+	}
+
+	/* Make sure the key of the read node is correct */
+	key_read(c, node + UBIFS_KEY_OFFSET, &key1);
+	if (!keys_eq(c, key, &key1)) {
+		ubifs_err(c, "bad key in node at LEB %d:%d",
+			  zbr->lnum, zbr->offs);
+		dbg_tnck(key, "looked for key ");
+		dbg_tnck(&key1, "but found node's key ");
+		ubifs_dump_node(c, node, zbr->len);
+		return -EINVAL;
+	}
+
+	err = ubifs_node_check_hash(c, node, zbr->hash);
+	if (err) {
+		ubifs_bad_hash(c, node, zbr->hash, zbr->lnum, zbr->offs);
+		return err;
+	}
+
+	return 0;
+}
diff --git a/ubifs-utils/libubifs/ubifs.h b/ubifs-utils/libubifs/ubifs.h
new file mode 100644
index 00000000..4226b21e
--- /dev/null
+++ b/ubifs-utils/libubifs/ubifs.h
@@ -0,0 +1,2164 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * This file is part of UBIFS.
+ *
+ * Copyright (C) 2006-2008 Nokia Corporation
+ *
+ * Authors: Artem Bityutskiy (Битюцкий Артём)
+ *          Adrian Hunter
+ */
+
+#ifndef __UBIFS_H__
+#define __UBIFS_H__
+
+#include <asm/div64.h>
+#include <linux/statfs.h>
+#include <linux/fs.h>
+#include <linux/err.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/rwsem.h>
+#include <linux/mtd/ubi.h>
+#include <linux/pagemap.h>
+#include <linux/backing-dev.h>
+#include <linux/security.h>
+#include <linux/xattr.h>
+#include <linux/random.h>
+#include <linux/sysfs.h>
+#include <linux/completion.h>
+#include <crypto/hash_info.h>
+#include <crypto/hash.h>
+#include <crypto/utils.h>
+
+#include <linux/fscrypt.h>
+
+#include "ubifs-media.h"
+
+/* Version of this UBIFS implementation */
+#define UBIFS_VERSION 1
+
+/* UBIFS file system VFS magic number */
+#define UBIFS_SUPER_MAGIC 0x24051905
+
+/* Number of UBIFS blocks per VFS page */
+#define UBIFS_BLOCKS_PER_PAGE (PAGE_SIZE / UBIFS_BLOCK_SIZE)
+#define UBIFS_BLOCKS_PER_PAGE_SHIFT (PAGE_SHIFT - UBIFS_BLOCK_SHIFT)
+
+/* "File system end of life" sequence number watermark */
+#define SQNUM_WARN_WATERMARK 0xFFFFFFFF00000000ULL
+#define SQNUM_WATERMARK      0xFFFFFFFFFF000000ULL
+
+/*
+ * Minimum amount of LEBs reserved for the index. At present the index needs at
+ * least 2 LEBs: one for the index head and one for in-the-gaps method (which
+ * currently does not cater for the index head and so excludes it from
+ * consideration).
+ */
+#define MIN_INDEX_LEBS 2
+
+/* Minimum amount of data UBIFS writes to the flash */
+#define MIN_WRITE_SZ (UBIFS_DATA_NODE_SZ + 8)
+
+/*
+ * Currently we do not support inode number overlapping and re-using, so this
+ * watermark defines dangerous inode number level. This should be fixed later,
+ * although it is difficult to exceed current limit. Another option is to use
+ * 64-bit inode numbers, but this means more overhead.
+ */
+#define INUM_WARN_WATERMARK 0xFFF00000
+#define INUM_WATERMARK      0xFFFFFF00
+
+/* Maximum number of entries in each LPT (LEB category) heap */
+#define LPT_HEAP_SZ 256
+
+/*
+ * Background thread name pattern. The numbers are UBI device and volume
+ * numbers.
+ */
+#define BGT_NAME_PATTERN "ubifs_bgt%d_%d"
+
+/* Maximum possible inode number (only 32-bit inodes are supported now) */
+#define MAX_INUM 0xFFFFFFFF
+
+/* Number of non-data journal heads */
+#define NONDATA_JHEADS_CNT 2
+
+/* Shorter names for journal head numbers for internal usage */
+#define GCHD   UBIFS_GC_HEAD
+#define BASEHD UBIFS_BASE_HEAD
+#define DATAHD UBIFS_DATA_HEAD
+
+/* 'No change' value for 'ubifs_change_lp()' */
+#define LPROPS_NC 0x80000001
+
+/*
+ * There is no notion of truncation key because truncation nodes do not exist
+ * in TNC. However, when replaying, it is handy to introduce fake "truncation"
+ * keys for truncation nodes because the code becomes simpler. So we define
+ * %UBIFS_TRUN_KEY type.
+ *
+ * But otherwise, out of the journal reply scope, the truncation keys are
+ * invalid.
+ */
+#define UBIFS_TRUN_KEY    UBIFS_KEY_TYPES_CNT
+#define UBIFS_INVALID_KEY UBIFS_KEY_TYPES_CNT
+
+/*
+ * How much a directory entry/extended attribute entry adds to the parent/host
+ * inode.
+ */
+#define CALC_DENT_SIZE(name_len) ALIGN(UBIFS_DENT_NODE_SZ + (name_len) + 1, 8)
+
+/* How much an extended attribute adds to the host inode */
+#define CALC_XATTR_BYTES(data_len) ALIGN(UBIFS_INO_NODE_SZ + (data_len) + 1, 8)
+
+/*
+ * Znodes which were not touched for 'OLD_ZNODE_AGE' seconds are considered
+ * "old", and znode which were touched last 'YOUNG_ZNODE_AGE' seconds ago are
+ * considered "young". This is used by shrinker when selecting znode to trim
+ * off.
+ */
+#define OLD_ZNODE_AGE 20
+#define YOUNG_ZNODE_AGE 5
+
+/*
+ * Some compressors, like LZO, may end up with more data then the input buffer.
+ * So UBIFS always allocates larger output buffer, to be sure the compressor
+ * will not corrupt memory in case of worst case compression.
+ */
+#define WORST_COMPR_FACTOR 2
+
+#ifdef CONFIG_FS_ENCRYPTION
+#define UBIFS_CIPHER_BLOCK_SIZE FSCRYPT_CONTENTS_ALIGNMENT
+#else
+#define UBIFS_CIPHER_BLOCK_SIZE 0
+#endif
+
+/*
+ * How much memory is needed for a buffer where we compress a data node.
+ */
+#define COMPRESSED_DATA_NODE_BUF_SZ \
+	(UBIFS_DATA_NODE_SZ + UBIFS_BLOCK_SIZE * WORST_COMPR_FACTOR)
+
+/* Maximum expected tree height for use by bottom_up_buf */
+#define BOTTOM_UP_HEIGHT 64
+
+/* Maximum number of data nodes to bulk-read */
+#define UBIFS_MAX_BULK_READ 32
+
+#ifdef CONFIG_UBIFS_FS_AUTHENTICATION
+#define UBIFS_HASH_ARR_SZ UBIFS_MAX_HASH_LEN
+#define UBIFS_HMAC_ARR_SZ UBIFS_MAX_HMAC_LEN
+#else
+#define UBIFS_HASH_ARR_SZ 0
+#define UBIFS_HMAC_ARR_SZ 0
+#endif
+
+/*
+ * The UBIFS sysfs directory name pattern and maximum name length (3 for "ubi"
+ * + 1 for "_" and plus 2x2 for 2 UBI numbers and 1 for the trailing zero byte.
+ */
+#define UBIFS_DFS_DIR_NAME "ubi%d_%d"
+#define UBIFS_DFS_DIR_LEN  (3 + 1 + 2*2 + 1)
+
+/*
+ * Lockdep classes for UBIFS inode @ui_mutex.
+ */
+enum {
+	WB_MUTEX_1 = 0,
+	WB_MUTEX_2 = 1,
+	WB_MUTEX_3 = 2,
+	WB_MUTEX_4 = 3,
+};
+
+/*
+ * Znode flags (actually, bit numbers which store the flags).
+ *
+ * DIRTY_ZNODE: znode is dirty
+ * COW_ZNODE: znode is being committed and a new instance of this znode has to
+ *            be created before changing this znode
+ * OBSOLETE_ZNODE: znode is obsolete, which means it was deleted, but it is
+ *                 still in the commit list and the ongoing commit operation
+ *                 will commit it, and delete this znode after it is done
+ */
+enum {
+	DIRTY_ZNODE    = 0,
+	COW_ZNODE      = 1,
+	OBSOLETE_ZNODE = 2,
+};
+
+/*
+ * Commit states.
+ *
+ * COMMIT_RESTING: commit is not wanted
+ * COMMIT_BACKGROUND: background commit has been requested
+ * COMMIT_REQUIRED: commit is required
+ * COMMIT_RUNNING_BACKGROUND: background commit is running
+ * COMMIT_RUNNING_REQUIRED: commit is running and it is required
+ * COMMIT_BROKEN: commit failed
+ */
+enum {
+	COMMIT_RESTING = 0,
+	COMMIT_BACKGROUND,
+	COMMIT_REQUIRED,
+	COMMIT_RUNNING_BACKGROUND,
+	COMMIT_RUNNING_REQUIRED,
+	COMMIT_BROKEN,
+};
+
+/*
+ * 'ubifs_scan_a_node()' return values.
+ *
+ * SCANNED_GARBAGE:  scanned garbage
+ * SCANNED_EMPTY_SPACE: scanned empty space
+ * SCANNED_A_NODE: scanned a valid node
+ * SCANNED_A_CORRUPT_NODE: scanned a corrupted node
+ * SCANNED_A_BAD_PAD_NODE: scanned a padding node with invalid pad length
+ *
+ * Greater than zero means: 'scanned that number of padding bytes'
+ */
+enum {
+	SCANNED_GARBAGE        = 0,
+	SCANNED_EMPTY_SPACE    = -1,
+	SCANNED_A_NODE         = -2,
+	SCANNED_A_CORRUPT_NODE = -3,
+	SCANNED_A_BAD_PAD_NODE = -4,
+};
+
+/*
+ * LPT cnode flag bits.
+ *
+ * DIRTY_CNODE: cnode is dirty
+ * OBSOLETE_CNODE: cnode is being committed and has been copied (or deleted),
+ *                 so it can (and must) be freed when the commit is finished
+ * COW_CNODE: cnode is being committed and must be copied before writing
+ */
+enum {
+	DIRTY_CNODE    = 0,
+	OBSOLETE_CNODE = 1,
+	COW_CNODE      = 2,
+};
+
+/*
+ * Dirty flag bits (lpt_drty_flgs) for LPT special nodes.
+ *
+ * LTAB_DIRTY: ltab node is dirty
+ * LSAVE_DIRTY: lsave node is dirty
+ */
+enum {
+	LTAB_DIRTY  = 1,
+	LSAVE_DIRTY = 2,
+};
+
+/*
+ * Return codes used by the garbage collector.
+ * @LEB_FREED: the logical eraseblock was freed and is ready to use
+ * @LEB_FREED_IDX: indexing LEB was freed and can be used only after the commit
+ * @LEB_RETAINED: the logical eraseblock was freed and retained for GC purposes
+ */
+enum {
+	LEB_FREED,
+	LEB_FREED_IDX,
+	LEB_RETAINED,
+};
+
+/*
+ * Action taken upon a failed ubifs_assert().
+ * @ASSACT_REPORT: just report the failed assertion
+ * @ASSACT_RO: switch to read-only mode
+ * @ASSACT_PANIC: call BUG() and possible panic the kernel
+ */
+enum {
+	ASSACT_REPORT = 0,
+	ASSACT_RO,
+	ASSACT_PANIC,
+};
+
+/**
+ * struct ubifs_old_idx - index node obsoleted since last commit start.
+ * @rb: rb-tree node
+ * @lnum: LEB number of obsoleted index node
+ * @offs: offset of obsoleted index node
+ */
+struct ubifs_old_idx {
+	struct rb_node rb;
+	int lnum;
+	int offs;
+};
+
+/* The below union makes it easier to deal with keys */
+union ubifs_key {
+	uint8_t u8[UBIFS_SK_LEN];
+	uint32_t u32[UBIFS_SK_LEN/4];
+	uint64_t u64[UBIFS_SK_LEN/8];
+	__le32 j32[UBIFS_SK_LEN/4];
+};
+
+/**
+ * struct ubifs_scan_node - UBIFS scanned node information.
+ * @list: list of scanned nodes
+ * @key: key of node scanned (if it has one)
+ * @sqnum: sequence number
+ * @type: type of node scanned
+ * @offs: offset with LEB of node scanned
+ * @len: length of node scanned
+ * @node: raw node
+ */
+struct ubifs_scan_node {
+	struct list_head list;
+	union ubifs_key key;
+	unsigned long long sqnum;
+	int type;
+	int offs;
+	int len;
+	void *node;
+};
+
+/**
+ * struct ubifs_scan_leb - UBIFS scanned LEB information.
+ * @lnum: logical eraseblock number
+ * @nodes_cnt: number of nodes scanned
+ * @nodes: list of struct ubifs_scan_node
+ * @endpt: end point (and therefore the start of empty space)
+ * @buf: buffer containing entire LEB scanned
+ */
+struct ubifs_scan_leb {
+	int lnum;
+	int nodes_cnt;
+	struct list_head nodes;
+	int endpt;
+	void *buf;
+};
+
+/**
+ * struct ubifs_gced_idx_leb - garbage-collected indexing LEB.
+ * @list: list
+ * @lnum: LEB number
+ * @unmap: OK to unmap this LEB
+ *
+ * This data structure is used to temporary store garbage-collected indexing
+ * LEBs - they are not released immediately, but only after the next commit.
+ * This is needed to guarantee recoverability.
+ */
+struct ubifs_gced_idx_leb {
+	struct list_head list;
+	int lnum;
+	int unmap;
+};
+
+/**
+ * struct ubifs_inode - UBIFS in-memory inode description.
+ * @vfs_inode: VFS inode description object
+ * @creat_sqnum: sequence number at time of creation
+ * @del_cmtno: commit number corresponding to the time the inode was deleted,
+ *             protected by @c->commit_sem;
+ * @xattr_size: summarized size of all extended attributes in bytes
+ * @xattr_cnt: count of extended attributes this inode has
+ * @xattr_names: sum of lengths of all extended attribute names belonging to
+ *               this inode
+ * @dirty: non-zero if the inode is dirty
+ * @xattr: non-zero if this is an extended attribute inode
+ * @bulk_read: non-zero if bulk-read should be used
+ * @ui_mutex: serializes inode write-back with the rest of VFS operations,
+ *            serializes "clean <-> dirty" state changes, serializes bulk-read,
+ *            protects @dirty, @bulk_read, @ui_size, and @xattr_size
+ * @xattr_sem: serilizes write operations (remove|set|create) on xattr
+ * @ui_lock: protects @synced_i_size
+ * @synced_i_size: synchronized size of inode, i.e. the value of inode size
+ *                 currently stored on the flash; used only for regular file
+ *                 inodes
+ * @ui_size: inode size used by UBIFS when writing to flash
+ * @flags: inode flags (@UBIFS_COMPR_FL, etc)
+ * @compr_type: default compression type used for this inode
+ * @last_page_read: page number of last page read (for bulk read)
+ * @read_in_a_row: number of consecutive pages read in a row (for bulk read)
+ * @data_len: length of the data attached to the inode
+ * @data: inode's data
+ *
+ * @ui_mutex exists for two main reasons. At first it prevents inodes from
+ * being written back while UBIFS changing them, being in the middle of an VFS
+ * operation. This way UBIFS makes sure the inode fields are consistent. For
+ * example, in 'ubifs_rename()' we change 4 inodes simultaneously, and
+ * write-back must not write any of them before we have finished.
+ *
+ * The second reason is budgeting - UBIFS has to budget all operations. If an
+ * operation is going to mark an inode dirty, it has to allocate budget for
+ * this. It cannot just mark it dirty because there is no guarantee there will
+ * be enough flash space to write the inode back later. This means UBIFS has
+ * to have full control over inode "clean <-> dirty" transitions (and pages
+ * actually). But unfortunately, VFS marks inodes dirty in many places, and it
+ * does not ask the file-system if it is allowed to do so (there is a notifier,
+ * but it is not enough), i.e., there is no mechanism to synchronize with this.
+ * So UBIFS has its own inode dirty flag and its own mutex to serialize
+ * "clean <-> dirty" transitions.
+ *
+ * The @synced_i_size field is used to make sure we never write pages which are
+ * beyond last synchronized inode size. See 'ubifs_writepage()' for more
+ * information.
+ *
+ * The @ui_size is a "shadow" variable for @inode->i_size and UBIFS uses
+ * @ui_size instead of @inode->i_size. The reason for this is that UBIFS cannot
+ * make sure @inode->i_size is always changed under @ui_mutex, because it
+ * cannot call 'truncate_setsize()' with @ui_mutex locked, because it would
+ * deadlock with 'ubifs_writepage()' (see file.c). All the other inode fields
+ * are changed under @ui_mutex, so they do not need "shadow" fields. Note, one
+ * could consider to rework locking and base it on "shadow" fields.
+ */
+struct ubifs_inode {
+	struct inode vfs_inode;
+	unsigned long long creat_sqnum;
+	unsigned long long del_cmtno;
+	unsigned int xattr_size;
+	unsigned int xattr_cnt;
+	unsigned int xattr_names;
+	unsigned int dirty:1;
+	unsigned int xattr:1;
+	unsigned int bulk_read:1;
+	unsigned int compr_type:2;
+	struct mutex ui_mutex;
+	struct rw_semaphore xattr_sem;
+	spinlock_t ui_lock;
+	loff_t synced_i_size;
+	loff_t ui_size;
+	int flags;
+	pgoff_t last_page_read;
+	pgoff_t read_in_a_row;
+	int data_len;
+	void *data;
+};
+
+/**
+ * struct ubifs_unclean_leb - records a LEB recovered under read-only mode.
+ * @list: list
+ * @lnum: LEB number of recovered LEB
+ * @endpt: offset where recovery ended
+ *
+ * This structure records a LEB identified during recovery that needs to be
+ * cleaned but was not because UBIFS was mounted read-only. The information
+ * is used to clean the LEB when remounting to read-write mode.
+ */
+struct ubifs_unclean_leb {
+	struct list_head list;
+	int lnum;
+	int endpt;
+};
+
+/*
+ * LEB properties flags.
+ *
+ * LPROPS_UNCAT: not categorized
+ * LPROPS_DIRTY: dirty > free, dirty >= @c->dead_wm, not index
+ * LPROPS_DIRTY_IDX: dirty + free > @c->min_idx_node_sze and index
+ * LPROPS_FREE: free > 0, dirty < @c->dead_wm, not empty, not index
+ * LPROPS_HEAP_CNT: number of heaps used for storing categorized LEBs
+ * LPROPS_EMPTY: LEB is empty, not taken
+ * LPROPS_FREEABLE: free + dirty == leb_size, not index, not taken
+ * LPROPS_FRDI_IDX: free + dirty == leb_size and index, may be taken
+ * LPROPS_CAT_MASK: mask for the LEB categories above
+ * LPROPS_TAKEN: LEB was taken (this flag is not saved on the media)
+ * LPROPS_INDEX: LEB contains indexing nodes (this flag also exists on flash)
+ */
+enum {
+	LPROPS_UNCAT     =  0,
+	LPROPS_DIRTY     =  1,
+	LPROPS_DIRTY_IDX =  2,
+	LPROPS_FREE      =  3,
+	LPROPS_HEAP_CNT  =  3,
+	LPROPS_EMPTY     =  4,
+	LPROPS_FREEABLE  =  5,
+	LPROPS_FRDI_IDX  =  6,
+	LPROPS_CAT_MASK  = 15,
+	LPROPS_TAKEN     = 16,
+	LPROPS_INDEX     = 32,
+};
+
+/**
+ * struct ubifs_lprops - logical eraseblock properties.
+ * @free: amount of free space in bytes
+ * @dirty: amount of dirty space in bytes
+ * @flags: LEB properties flags (see above)
+ * @lnum: LEB number
+ * @list: list of same-category lprops (for LPROPS_EMPTY and LPROPS_FREEABLE)
+ * @hpos: heap position in heap of same-category lprops (other categories)
+ */
+struct ubifs_lprops {
+	int free;
+	int dirty;
+	int flags;
+	int lnum;
+	union {
+		struct list_head list;
+		int hpos;
+	};
+};
+
+/**
+ * struct ubifs_lpt_lprops - LPT logical eraseblock properties.
+ * @free: amount of free space in bytes
+ * @dirty: amount of dirty space in bytes
+ * @tgc: trivial GC flag (1 => unmap after commit end)
+ * @cmt: commit flag (1 => reserved for commit)
+ */
+struct ubifs_lpt_lprops {
+	int free;
+	int dirty;
+	unsigned tgc:1;
+	unsigned cmt:1;
+};
+
+/**
+ * struct ubifs_lp_stats - statistics of eraseblocks in the main area.
+ * @empty_lebs: number of empty LEBs
+ * @taken_empty_lebs: number of taken LEBs
+ * @idx_lebs: number of indexing LEBs
+ * @total_free: total free space in bytes (includes all LEBs)
+ * @total_dirty: total dirty space in bytes (includes all LEBs)
+ * @total_used: total used space in bytes (does not include index LEBs)
+ * @total_dead: total dead space in bytes (does not include index LEBs)
+ * @total_dark: total dark space in bytes (does not include index LEBs)
+ *
+ * The @taken_empty_lebs field counts the LEBs that are in the transient state
+ * of having been "taken" for use but not yet written to. @taken_empty_lebs is
+ * needed to account correctly for @gc_lnum, otherwise @empty_lebs could be
+ * used by itself (in which case 'unused_lebs' would be a better name). In the
+ * case of @gc_lnum, it is "taken" at mount time or whenever a LEB is retained
+ * by GC, but unlike other empty LEBs that are "taken", it may not be written
+ * straight away (i.e. before the next commit start or unmount), so either
+ * @gc_lnum must be specially accounted for, or the current approach followed
+ * i.e. count it under @taken_empty_lebs.
+ *
+ * @empty_lebs includes @taken_empty_lebs.
+ *
+ * @total_used, @total_dead and @total_dark fields do not account indexing
+ * LEBs.
+ */
+struct ubifs_lp_stats {
+	int empty_lebs;
+	int taken_empty_lebs;
+	int idx_lebs;
+	long long total_free;
+	long long total_dirty;
+	long long total_used;
+	long long total_dead;
+	long long total_dark;
+};
+
+struct ubifs_nnode;
+
+/**
+ * struct ubifs_cnode - LEB Properties Tree common node.
+ * @parent: parent nnode
+ * @cnext: next cnode to commit
+ * @flags: flags (%DIRTY_LPT_NODE or %OBSOLETE_LPT_NODE)
+ * @iip: index in parent
+ * @level: level in the tree (zero for pnodes, greater than zero for nnodes)
+ * @num: node number
+ */
+struct ubifs_cnode {
+	struct ubifs_nnode *parent;
+	struct ubifs_cnode *cnext;
+	unsigned long flags;
+	int iip;
+	int level;
+	int num;
+};
+
+/**
+ * struct ubifs_pnode - LEB Properties Tree leaf node.
+ * @parent: parent nnode
+ * @cnext: next cnode to commit
+ * @flags: flags (%DIRTY_LPT_NODE or %OBSOLETE_LPT_NODE)
+ * @iip: index in parent
+ * @level: level in the tree (always zero for pnodes)
+ * @num: node number
+ * @lprops: LEB properties array
+ */
+struct ubifs_pnode {
+	struct ubifs_nnode *parent;
+	struct ubifs_cnode *cnext;
+	unsigned long flags;
+	int iip;
+	int level;
+	int num;
+	struct ubifs_lprops lprops[UBIFS_LPT_FANOUT];
+};
+
+/**
+ * struct ubifs_nbranch - LEB Properties Tree internal node branch.
+ * @lnum: LEB number of child
+ * @offs: offset of child
+ * @nnode: nnode child
+ * @pnode: pnode child
+ * @cnode: cnode child
+ */
+struct ubifs_nbranch {
+	int lnum;
+	int offs;
+	union {
+		struct ubifs_nnode *nnode;
+		struct ubifs_pnode *pnode;
+		struct ubifs_cnode *cnode;
+	};
+};
+
+/**
+ * struct ubifs_nnode - LEB Properties Tree internal node.
+ * @parent: parent nnode
+ * @cnext: next cnode to commit
+ * @flags: flags (%DIRTY_LPT_NODE or %OBSOLETE_LPT_NODE)
+ * @iip: index in parent
+ * @level: level in the tree (always greater than zero for nnodes)
+ * @num: node number
+ * @nbranch: branches to child nodes
+ */
+struct ubifs_nnode {
+	struct ubifs_nnode *parent;
+	struct ubifs_cnode *cnext;
+	unsigned long flags;
+	int iip;
+	int level;
+	int num;
+	struct ubifs_nbranch nbranch[UBIFS_LPT_FANOUT];
+};
+
+/**
+ * struct ubifs_lpt_heap - heap of categorized lprops.
+ * @arr: heap array
+ * @cnt: number in heap
+ * @max_cnt: maximum number allowed in heap
+ *
+ * There are %LPROPS_HEAP_CNT heaps.
+ */
+struct ubifs_lpt_heap {
+	struct ubifs_lprops **arr;
+	int cnt;
+	int max_cnt;
+};
+
+/*
+ * Return codes for LPT scan callback function.
+ *
+ * LPT_SCAN_CONTINUE: continue scanning
+ * LPT_SCAN_ADD: add the LEB properties scanned to the tree in memory
+ * LPT_SCAN_STOP: stop scanning
+ */
+enum {
+	LPT_SCAN_CONTINUE = 0,
+	LPT_SCAN_ADD = 1,
+	LPT_SCAN_STOP = 2,
+};
+
+struct ubifs_info;
+
+/* Callback used by the 'ubifs_lpt_scan_nolock()' function */
+typedef int (*ubifs_lpt_scan_callback)(struct ubifs_info *c,
+				       const struct ubifs_lprops *lprops,
+				       int in_tree, void *data);
+
+/**
+ * struct ubifs_wbuf - UBIFS write-buffer.
+ * @c: UBIFS file-system description object
+ * @buf: write-buffer (of min. flash I/O unit size)
+ * @lnum: logical eraseblock number the write-buffer points to
+ * @offs: write-buffer offset in this logical eraseblock
+ * @avail: number of bytes available in the write-buffer
+ * @used:  number of used bytes in the write-buffer
+ * @size: write-buffer size (in [@c->min_io_size, @c->max_write_size] range)
+ * @jhead: journal head the mutex belongs to (note, needed only to shut lockdep
+ *         up by 'mutex_lock_nested()).
+ * @sync_callback: write-buffer synchronization callback
+ * @io_mutex: serializes write-buffer I/O
+ * @lock: serializes @buf, @lnum, @offs, @avail, @used, @next_ino and @inodes
+ *        fields
+ * @timer: write-buffer timer
+ * @no_timer: non-zero if this write-buffer does not have a timer
+ * @need_sync: non-zero if the timer expired and the wbuf needs sync'ing
+ * @next_ino: points to the next position of the following inode number
+ * @inodes: stores the inode numbers of the nodes which are in wbuf
+ *
+ * The write-buffer synchronization callback is called when the write-buffer is
+ * synchronized in order to notify how much space was wasted due to
+ * write-buffer padding and how much free space is left in the LEB.
+ *
+ * Note: the fields @buf, @lnum, @offs, @avail and @used can be read under
+ * spin-lock or mutex because they are written under both mutex and spin-lock.
+ * @buf is appended to under mutex but overwritten under both mutex and
+ * spin-lock. Thus the data between @buf and @buf + @used can be read under
+ * spinlock.
+ */
+struct ubifs_wbuf {
+	struct ubifs_info *c;
+	void *buf;
+	int lnum;
+	int offs;
+	int avail;
+	int used;
+	int size;
+	int jhead;
+	int (*sync_callback)(struct ubifs_info *c, int lnum, int free, int pad);
+	struct mutex io_mutex;
+	spinlock_t lock;
+	struct hrtimer timer;
+	unsigned int no_timer:1;
+	unsigned int need_sync:1;
+	int next_ino;
+	ino_t *inodes;
+};
+
+/**
+ * struct ubifs_bud - bud logical eraseblock.
+ * @lnum: logical eraseblock number
+ * @start: where the (uncommitted) bud data starts
+ * @jhead: journal head number this bud belongs to
+ * @list: link in the list buds belonging to the same journal head
+ * @rb: link in the tree of all buds
+ * @log_hash: the log hash from the commit start node up to this bud
+ */
+struct ubifs_bud {
+	int lnum;
+	int start;
+	int jhead;
+	struct list_head list;
+	struct rb_node rb;
+	struct shash_desc *log_hash;
+};
+
+/**
+ * struct ubifs_jhead - journal head.
+ * @wbuf: head's write-buffer
+ * @buds_list: list of bud LEBs belonging to this journal head
+ * @grouped: non-zero if UBIFS groups nodes when writing to this journal head
+ * @log_hash: the log hash from the commit start node up to this journal head
+ *
+ * Note, the @buds list is protected by the @c->buds_lock.
+ */
+struct ubifs_jhead {
+	struct ubifs_wbuf wbuf;
+	struct list_head buds_list;
+	unsigned int grouped:1;
+	struct shash_desc *log_hash;
+};
+
+/**
+ * struct ubifs_zbranch - key/coordinate/length branch stored in znodes.
+ * @key: key
+ * @znode: znode address in memory
+ * @lnum: LEB number of the target node (indexing node or data node)
+ * @offs: target node offset within @lnum
+ * @len: target node length
+ * @hash: the hash of the target node
+ */
+struct ubifs_zbranch {
+	union ubifs_key key;
+	union {
+		struct ubifs_znode *znode;
+		void *leaf;
+	};
+	int lnum;
+	int offs;
+	int len;
+	u8 hash[UBIFS_HASH_ARR_SZ];
+};
+
+/**
+ * struct ubifs_znode - in-memory representation of an indexing node.
+ * @parent: parent znode or NULL if it is the root
+ * @cnext: next znode to commit
+ * @cparent: parent node for this commit
+ * @ciip: index in cparent's zbranch array
+ * @flags: znode flags (%DIRTY_ZNODE, %COW_ZNODE or %OBSOLETE_ZNODE)
+ * @time: last access time (seconds)
+ * @level: level of the entry in the TNC tree
+ * @child_cnt: count of child znodes
+ * @iip: index in parent's zbranch array
+ * @alt: lower bound of key range has altered i.e. child inserted at slot 0
+ * @lnum: LEB number of the corresponding indexing node
+ * @offs: offset of the corresponding indexing node
+ * @len: length  of the corresponding indexing node
+ * @zbranch: array of znode branches (@c->fanout elements)
+ *
+ * Note! The @lnum, @offs, and @len fields are not really needed - we have them
+ * only for internal consistency check. They could be removed to save some RAM.
+ */
+struct ubifs_znode {
+	struct ubifs_znode *parent;
+	struct ubifs_znode *cnext;
+	struct ubifs_znode *cparent;
+	int ciip;
+	unsigned long flags;
+	time64_t time;
+	int level;
+	int child_cnt;
+	int iip;
+	int alt;
+	int lnum;
+	int offs;
+	int len;
+	struct ubifs_zbranch zbranch[];
+};
+
+/**
+ * struct bu_info - bulk-read information.
+ * @key: first data node key
+ * @zbranch: zbranches of data nodes to bulk read
+ * @buf: buffer to read into
+ * @buf_len: buffer length
+ * @gc_seq: GC sequence number to detect races with GC
+ * @cnt: number of data nodes for bulk read
+ * @blk_cnt: number of data blocks including holes
+ * @oef: end of file reached
+ */
+struct bu_info {
+	union ubifs_key key;
+	struct ubifs_zbranch zbranch[UBIFS_MAX_BULK_READ];
+	void *buf;
+	int buf_len;
+	int gc_seq;
+	int cnt;
+	int blk_cnt;
+	int eof;
+};
+
+/**
+ * struct ubifs_node_range - node length range description data structure.
+ * @len: fixed node length
+ * @min_len: minimum possible node length
+ * @max_len: maximum possible node length
+ *
+ * If @max_len is %0, the node has fixed length @len.
+ */
+struct ubifs_node_range {
+	union {
+		int len;
+		int min_len;
+	};
+	int max_len;
+};
+
+/**
+ * struct ubifs_compressor - UBIFS compressor description structure.
+ * @compr_type: compressor type (%UBIFS_COMPR_LZO, etc)
+ * @cc: cryptoapi compressor handle
+ * @comp_mutex: mutex used during compression
+ * @decomp_mutex: mutex used during decompression
+ * @name: compressor name
+ * @capi_name: cryptoapi compressor name
+ */
+struct ubifs_compressor {
+	int compr_type;
+	struct crypto_comp *cc;
+	struct mutex *comp_mutex;
+	struct mutex *decomp_mutex;
+	const char *name;
+	const char *capi_name;
+};
+
+/**
+ * struct ubifs_budget_req - budget requirements of an operation.
+ *
+ * @fast: non-zero if the budgeting should try to acquire budget quickly and
+ *        should not try to call write-back
+ * @recalculate: non-zero if @idx_growth, @data_growth, and @dd_growth fields
+ *               have to be re-calculated
+ * @new_page: non-zero if the operation adds a new page
+ * @dirtied_page: non-zero if the operation makes a page dirty
+ * @new_dent: non-zero if the operation adds a new directory entry
+ * @mod_dent: non-zero if the operation removes or modifies an existing
+ *            directory entry
+ * @new_ino: non-zero if the operation adds a new inode
+ * @new_ino_d: how much data newly created inode contains
+ * @dirtied_ino: how many inodes the operation makes dirty
+ * @dirtied_ino_d: how much data dirtied inode contains
+ * @idx_growth: how much the index will supposedly grow
+ * @data_growth: how much new data the operation will supposedly add
+ * @dd_growth: how much data that makes other data dirty the operation will
+ *             supposedly add
+ *
+ * @idx_growth, @data_growth and @dd_growth are not used in budget request. The
+ * budgeting subsystem caches index and data growth values there to avoid
+ * re-calculating them when the budget is released. However, if @idx_growth is
+ * %-1, it is calculated by the release function using other fields.
+ *
+ * An inode may contain 4KiB of data at max., thus the widths of @new_ino_d
+ * is 13 bits, and @dirtied_ino_d - 15, because up to 4 inodes may be made
+ * dirty by the re-name operation.
+ *
+ * Note, UBIFS aligns node lengths to 8-bytes boundary, so the requester has to
+ * make sure the amount of inode data which contribute to @new_ino_d and
+ * @dirtied_ino_d fields are aligned.
+ */
+struct ubifs_budget_req {
+	unsigned int fast:1;
+	unsigned int recalculate:1;
+#ifndef UBIFS_DEBUG
+	unsigned int new_page:1;
+	unsigned int dirtied_page:1;
+	unsigned int new_dent:1;
+	unsigned int mod_dent:1;
+	unsigned int new_ino:1;
+	unsigned int new_ino_d:13;
+	unsigned int dirtied_ino:4;
+	unsigned int dirtied_ino_d:15;
+#else
+	/* Not bit-fields to check for overflows */
+	unsigned int new_page;
+	unsigned int dirtied_page;
+	unsigned int new_dent;
+	unsigned int mod_dent;
+	unsigned int new_ino;
+	unsigned int new_ino_d;
+	unsigned int dirtied_ino;
+	unsigned int dirtied_ino_d;
+#endif
+	int idx_growth;
+	int data_growth;
+	int dd_growth;
+};
+
+/**
+ * struct ubifs_orphan - stores the inode number of an orphan.
+ * @rb: rb-tree node of rb-tree of orphans sorted by inode number
+ * @list: list head of list of orphans in order added
+ * @new_list: list head of list of orphans added since the last commit
+ * @cnext: next orphan to commit
+ * @dnext: next orphan to delete
+ * @inum: inode number
+ * @new: %1 => added since the last commit, otherwise %0
+ * @cmt: %1 => commit pending, otherwise %0
+ * @del: %1 => delete pending, otherwise %0
+ */
+struct ubifs_orphan {
+	struct rb_node rb;
+	struct list_head list;
+	struct list_head new_list;
+	struct ubifs_orphan *cnext;
+	struct ubifs_orphan *dnext;
+	ino_t inum;
+	unsigned new:1;
+	unsigned cmt:1;
+	unsigned del:1;
+};
+
+/**
+ * struct ubifs_mount_opts - UBIFS-specific mount options information.
+ * @unmount_mode: selected unmount mode (%0 default, %1 normal, %2 fast)
+ * @bulk_read: enable/disable bulk-reads (%0 default, %1 disable, %2 enable)
+ * @chk_data_crc: enable/disable CRC data checking when reading data nodes
+ *                (%0 default, %1 disable, %2 enable)
+ * @override_compr: override default compressor (%0 - do not override and use
+ *                  superblock compressor, %1 - override and use compressor
+ *                  specified in @compr_type)
+ * @compr_type: compressor type to override the superblock compressor with
+ *              (%UBIFS_COMPR_NONE, etc)
+ */
+struct ubifs_mount_opts {
+	unsigned int unmount_mode:2;
+	unsigned int bulk_read:2;
+	unsigned int chk_data_crc:2;
+	unsigned int override_compr:1;
+	unsigned int compr_type:2;
+};
+
+/**
+ * struct ubifs_budg_info - UBIFS budgeting information.
+ * @idx_growth: amount of bytes budgeted for index growth
+ * @data_growth: amount of bytes budgeted for cached data
+ * @dd_growth: amount of bytes budgeted for cached data that will make
+ *             other data dirty
+ * @uncommitted_idx: amount of bytes were budgeted for growth of the index, but
+ *                   which still have to be taken into account because the index
+ *                   has not been committed so far
+ * @old_idx_sz: size of index on flash
+ * @min_idx_lebs: minimum number of LEBs required for the index
+ * @nospace: non-zero if the file-system does not have flash space (used as
+ *           optimization)
+ * @nospace_rp: the same as @nospace, but additionally means that even reserved
+ *              pool is full
+ * @page_budget: budget for a page (constant, never changed after mount)
+ * @inode_budget: budget for an inode (constant, never changed after mount)
+ * @dent_budget: budget for a directory entry (constant, never changed after
+ *               mount)
+ */
+struct ubifs_budg_info {
+	long long idx_growth;
+	long long data_growth;
+	long long dd_growth;
+	long long uncommitted_idx;
+	unsigned long long old_idx_sz;
+	int min_idx_lebs;
+	unsigned int nospace:1;
+	unsigned int nospace_rp:1;
+	int page_budget;
+	int inode_budget;
+	int dent_budget;
+};
+
+/**
+ * ubifs_stats_info - per-FS statistics information.
+ * @magic_errors: number of bad magic numbers (will be reset with a new mount).
+ * @node_errors: number of bad nodes (will be reset with a new mount).
+ * @crc_errors: number of bad crcs (will be reset with a new mount).
+ */
+struct ubifs_stats_info {
+	unsigned int magic_errors;
+	unsigned int node_errors;
+	unsigned int crc_errors;
+};
+
+struct ubifs_debug_info;
+
+/**
+ * struct ubifs_info - UBIFS file-system description data structure
+ * (per-superblock).
+ * @vfs_sb: VFS @struct super_block object
+ * @sup_node: The super block node as read from the device
+ *
+ * @highest_inum: highest used inode number
+ * @max_sqnum: current global sequence number
+ * @cmt_no: commit number of the last successfully completed commit, protected
+ *          by @commit_sem
+ * @cnt_lock: protects @highest_inum and @max_sqnum counters
+ * @fmt_version: UBIFS on-flash format version
+ * @ro_compat_version: R/O compatibility version
+ * @uuid: UUID from super block
+ *
+ * @lhead_lnum: log head logical eraseblock number
+ * @lhead_offs: log head offset
+ * @ltail_lnum: log tail logical eraseblock number (offset is always 0)
+ * @log_mutex: protects the log, @lhead_lnum, @lhead_offs, @ltail_lnum, and
+ *             @bud_bytes
+ * @min_log_bytes: minimum required number of bytes in the log
+ * @cmt_bud_bytes: used during commit to temporarily amount of bytes in
+ *                 committed buds
+ *
+ * @buds: tree of all buds indexed by bud LEB number
+ * @bud_bytes: how many bytes of flash is used by buds
+ * @buds_lock: protects the @buds tree, @bud_bytes, and per-journal head bud
+ *             lists
+ * @jhead_cnt: count of journal heads
+ * @jheads: journal heads (head zero is base head)
+ * @max_bud_bytes: maximum number of bytes allowed in buds
+ * @bg_bud_bytes: number of bud bytes when background commit is initiated
+ * @old_buds: buds to be released after commit ends
+ * @max_bud_cnt: maximum number of buds
+ *
+ * @commit_sem: synchronizes committer with other processes
+ * @cmt_state: commit state
+ * @cs_lock: commit state lock
+ * @cmt_wq: wait queue to sleep on if the log is full and a commit is running
+ *
+ * @big_lpt: flag that LPT is too big to write whole during commit
+ * @space_fixup: flag indicating that free space in LEBs needs to be cleaned up
+ * @double_hash: flag indicating that we can do lookups by hash
+ * @encrypted: flag indicating that this file system contains encrypted files
+ * @no_chk_data_crc: do not check CRCs when reading data nodes (except during
+ *                   recovery)
+ * @bulk_read: enable bulk-reads
+ * @default_compr: default compression algorithm (%UBIFS_COMPR_LZO, etc)
+ * @rw_incompat: the media is not R/W compatible
+ * @assert_action: action to take when a ubifs_assert() fails
+ * @authenticated: flag indigating the FS is mounted in authenticated mode
+ *
+ * @tnc_mutex: protects the Tree Node Cache (TNC), @zroot, @cnext, @enext, and
+ *             @calc_idx_sz
+ * @zroot: zbranch which points to the root index node and znode
+ * @cnext: next znode to commit
+ * @enext: next znode to commit to empty space
+ * @gap_lebs: array of LEBs used by the in-gaps commit method
+ * @cbuf: commit buffer
+ * @ileb_buf: buffer for commit in-the-gaps method
+ * @ileb_len: length of data in ileb_buf
+ * @ihead_lnum: LEB number of index head
+ * @ihead_offs: offset of index head
+ * @ilebs: pre-allocated index LEBs
+ * @ileb_cnt: number of pre-allocated index LEBs
+ * @ileb_nxt: next pre-allocated index LEBs
+ * @old_idx: tree of index nodes obsoleted since the last commit start
+ * @bottom_up_buf: a buffer which is used by 'dirty_cow_bottom_up()' in tnc.c
+ *
+ * @mst_node: master node
+ * @mst_offs: offset of valid master node
+ *
+ * @max_bu_buf_len: maximum bulk-read buffer length
+ * @bu_mutex: protects the pre-allocated bulk-read buffer and @c->bu
+ * @bu: pre-allocated bulk-read information
+ *
+ * @write_reserve_mutex: protects @write_reserve_buf
+ * @write_reserve_buf: on the write path we allocate memory, which might
+ *                     sometimes be unavailable, in which case we use this
+ *                     write reserve buffer
+ *
+ * @log_lebs: number of logical eraseblocks in the log
+ * @log_bytes: log size in bytes
+ * @log_last: last LEB of the log
+ * @lpt_lebs: number of LEBs used for lprops table
+ * @lpt_first: first LEB of the lprops table area
+ * @lpt_last: last LEB of the lprops table area
+ * @orph_lebs: number of LEBs used for the orphan area
+ * @orph_first: first LEB of the orphan area
+ * @orph_last: last LEB of the orphan area
+ * @main_lebs: count of LEBs in the main area
+ * @main_first: first LEB of the main area
+ * @main_bytes: main area size in bytes
+ *
+ * @key_hash_type: type of the key hash
+ * @key_hash: direntry key hash function
+ * @key_fmt: key format
+ * @key_len: key length
+ * @hash_len: The length of the index node hashes
+ * @fanout: fanout of the index tree (number of links per indexing node)
+ *
+ * @min_io_size: minimal input/output unit size
+ * @min_io_shift: number of bits in @min_io_size minus one
+ * @max_write_size: maximum amount of bytes the underlying flash can write at a
+ *                  time (MTD write buffer size)
+ * @max_write_shift: number of bits in @max_write_size minus one
+ * @leb_size: logical eraseblock size in bytes
+ * @leb_start: starting offset of logical eraseblocks within physical
+ *             eraseblocks
+ * @half_leb_size: half LEB size
+ * @idx_leb_size: how many bytes of an LEB are effectively available when it is
+ *                used to store indexing nodes (@leb_size - @max_idx_node_sz)
+ * @leb_cnt: count of logical eraseblocks
+ * @max_leb_cnt: maximum count of logical eraseblocks
+ * @ro_media: the underlying UBI volume is read-only
+ * @ro_mount: the file-system was mounted as read-only
+ * @ro_error: UBIFS switched to R/O mode because an error happened
+ *
+ * @dirty_pg_cnt: number of dirty pages (not used)
+ * @dirty_zn_cnt: number of dirty znodes
+ * @clean_zn_cnt: number of clean znodes
+ *
+ * @space_lock: protects @bi and @lst
+ * @lst: lprops statistics
+ * @bi: budgeting information
+ * @calc_idx_sz: temporary variable which is used to calculate new index size
+ *               (contains accurate new index size at end of TNC commit start)
+ *
+ * @ref_node_alsz: size of the LEB reference node aligned to the min. flash
+ *                 I/O unit
+ * @mst_node_alsz: master node aligned size
+ * @min_idx_node_sz: minimum indexing node aligned on 8-bytes boundary
+ * @max_idx_node_sz: maximum indexing node aligned on 8-bytes boundary
+ * @max_inode_sz: maximum possible inode size in bytes
+ * @max_znode_sz: size of znode in bytes
+ *
+ * @leb_overhead: how many bytes are wasted in an LEB when it is filled with
+ *                data nodes of maximum size - used in free space reporting
+ * @dead_wm: LEB dead space watermark
+ * @dark_wm: LEB dark space watermark
+ * @block_cnt: count of 4KiB blocks on the FS
+ *
+ * @ranges: UBIFS node length ranges
+ * @ubi: UBI volume descriptor
+ * @di: UBI device information
+ * @vi: UBI volume information
+ *
+ * @orph_tree: rb-tree of orphan inode numbers
+ * @orph_list: list of orphan inode numbers in order added
+ * @orph_new: list of orphan inode numbers added since last commit
+ * @orph_cnext: next orphan to commit
+ * @orph_dnext: next orphan to delete
+ * @orphan_lock: lock for orph_tree and orph_new
+ * @orph_buf: buffer for orphan nodes
+ * @new_orphans: number of orphans since last commit
+ * @cmt_orphans: number of orphans being committed
+ * @tot_orphans: number of orphans in the rb_tree
+ * @max_orphans: maximum number of orphans allowed
+ * @ohead_lnum: orphan head LEB number
+ * @ohead_offs: orphan head offset
+ * @no_orphs: non-zero if there are no orphans
+ *
+ * @bgt: UBIFS background thread
+ * @bgt_name: background thread name
+ * @need_bgt: if background thread should run
+ * @need_wbuf_sync: if write-buffers have to be synchronized
+ *
+ * @gc_lnum: LEB number used for garbage collection
+ * @sbuf: a buffer of LEB size used by GC and replay for scanning
+ * @idx_gc: list of index LEBs that have been garbage collected
+ * @idx_gc_cnt: number of elements on the idx_gc list
+ * @gc_seq: incremented for every non-index LEB garbage collected
+ * @gced_lnum: last non-index LEB that was garbage collected
+ *
+ * @infos_list: links all 'ubifs_info' objects
+ * @umount_mutex: serializes shrinker and un-mount
+ * @shrinker_run_no: shrinker run number
+ *
+ * @space_bits: number of bits needed to record free or dirty space
+ * @lpt_lnum_bits: number of bits needed to record a LEB number in the LPT
+ * @lpt_offs_bits: number of bits needed to record an offset in the LPT
+ * @lpt_spc_bits: number of bits needed to space in the LPT
+ * @pcnt_bits: number of bits needed to record pnode or nnode number
+ * @lnum_bits: number of bits needed to record LEB number
+ * @nnode_sz: size of on-flash nnode
+ * @pnode_sz: size of on-flash pnode
+ * @ltab_sz: size of on-flash LPT lprops table
+ * @lsave_sz: size of on-flash LPT save table
+ * @pnode_cnt: number of pnodes
+ * @nnode_cnt: number of nnodes
+ * @lpt_hght: height of the LPT
+ * @pnodes_have: number of pnodes in memory
+ *
+ * @lp_mutex: protects lprops table and all the other lprops-related fields
+ * @lpt_lnum: LEB number of the root nnode of the LPT
+ * @lpt_offs: offset of the root nnode of the LPT
+ * @nhead_lnum: LEB number of LPT head
+ * @nhead_offs: offset of LPT head
+ * @lpt_drty_flgs: dirty flags for LPT special nodes e.g. ltab
+ * @dirty_nn_cnt: number of dirty nnodes
+ * @dirty_pn_cnt: number of dirty pnodes
+ * @check_lpt_free: flag that indicates LPT GC may be needed
+ * @lpt_sz: LPT size
+ * @lpt_nod_buf: buffer for an on-flash nnode or pnode
+ * @lpt_buf: buffer of LEB size used by LPT
+ * @nroot: address in memory of the root nnode of the LPT
+ * @lpt_cnext: next LPT node to commit
+ * @lpt_heap: array of heaps of categorized lprops
+ * @dirty_idx: a (reverse sorted) copy of the LPROPS_DIRTY_IDX heap as at
+ *             previous commit start
+ * @uncat_list: list of un-categorized LEBs
+ * @empty_list: list of empty LEBs
+ * @freeable_list: list of freeable non-index LEBs (free + dirty == @leb_size)
+ * @frdi_idx_list: list of freeable index LEBs (free + dirty == @leb_size)
+ * @freeable_cnt: number of freeable LEBs in @freeable_list
+ * @in_a_category_cnt: count of lprops which are in a certain category, which
+ *                     basically meants that they were loaded from the flash
+ *
+ * @ltab_lnum: LEB number of LPT's own lprops table
+ * @ltab_offs: offset of LPT's own lprops table
+ * @ltab: LPT's own lprops table
+ * @ltab_cmt: LPT's own lprops table (commit copy)
+ * @lsave_cnt: number of LEB numbers in LPT's save table
+ * @lsave_lnum: LEB number of LPT's save table
+ * @lsave_offs: offset of LPT's save table
+ * @lsave: LPT's save table
+ * @lscan_lnum: LEB number of last LPT scan
+ *
+ * @rp_size: size of the reserved pool in bytes
+ * @report_rp_size: size of the reserved pool reported to user-space
+ * @rp_uid: reserved pool user ID
+ * @rp_gid: reserved pool group ID
+ *
+ * @hash_tfm: the hash transformation used for hashing nodes
+ * @hmac_tfm: the HMAC transformation for this filesystem
+ * @hmac_desc_len: length of the HMAC used for authentication
+ * @auth_key_name: the authentication key name
+ * @auth_hash_name: the name of the hash algorithm used for authentication
+ * @auth_hash_algo: the authentication hash used for this fs
+ * @log_hash: the log hash from the commit start node up to the latest reference
+ *            node.
+ *
+ * @empty: %1 if the UBI device is empty
+ * @need_recovery: %1 if the file-system needs recovery
+ * @replaying: %1 during journal replay
+ * @mounting: %1 while mounting
+ * @probing: %1 while attempting to mount if SB_SILENT mount flag is set
+ * @remounting_rw: %1 while re-mounting from R/O mode to R/W mode
+ * @replay_list: temporary list used during journal replay
+ * @replay_buds: list of buds to replay
+ * @cs_sqnum: sequence number of first node in the log (commit start node)
+ * @unclean_leb_list: LEBs to recover when re-mounting R/O mounted FS to R/W
+ *                    mode
+ * @rcvrd_mst_node: recovered master node to write when re-mounting R/O mounted
+ *                  FS to R/W mode
+ * @size_tree: inode size information for recovery
+ * @mount_opts: UBIFS-specific mount options
+ *
+ * @dbg: debugging-related information
+ * @stats: statistics exported over sysfs
+ *
+ * @kobj: kobject for /sys/fs/ubifs/
+ * @kobj_unregister: completion to unregister sysfs kobject
+ */
+struct ubifs_info {
+	struct super_block *vfs_sb;
+	struct ubifs_sb_node *sup_node;
+
+	ino_t highest_inum;
+	unsigned long long max_sqnum;
+	unsigned long long cmt_no;
+	spinlock_t cnt_lock;
+	int fmt_version;
+	int ro_compat_version;
+	unsigned char uuid[16];
+
+	int lhead_lnum;
+	int lhead_offs;
+	int ltail_lnum;
+	struct mutex log_mutex;
+	int min_log_bytes;
+	long long cmt_bud_bytes;
+
+	struct rb_root buds;
+	long long bud_bytes;
+	spinlock_t buds_lock;
+	int jhead_cnt;
+	struct ubifs_jhead *jheads;
+	long long max_bud_bytes;
+	long long bg_bud_bytes;
+	struct list_head old_buds;
+	int max_bud_cnt;
+
+	struct rw_semaphore commit_sem;
+	int cmt_state;
+	spinlock_t cs_lock;
+	wait_queue_head_t cmt_wq;
+
+	struct kobject kobj;
+	struct completion kobj_unregister;
+
+	unsigned int big_lpt:1;
+	unsigned int space_fixup:1;
+	unsigned int double_hash:1;
+	unsigned int encrypted:1;
+	unsigned int no_chk_data_crc:1;
+	unsigned int bulk_read:1;
+	unsigned int default_compr:2;
+	unsigned int rw_incompat:1;
+	unsigned int assert_action:2;
+	unsigned int authenticated:1;
+	unsigned int superblock_need_write:1;
+
+	struct mutex tnc_mutex;
+	struct ubifs_zbranch zroot;
+	struct ubifs_znode *cnext;
+	struct ubifs_znode *enext;
+	int *gap_lebs;
+	void *cbuf;
+	void *ileb_buf;
+	int ileb_len;
+	int ihead_lnum;
+	int ihead_offs;
+	int *ilebs;
+	int ileb_cnt;
+	int ileb_nxt;
+	struct rb_root old_idx;
+	int *bottom_up_buf;
+
+	struct ubifs_mst_node *mst_node;
+	int mst_offs;
+
+	int max_bu_buf_len;
+	struct mutex bu_mutex;
+	struct bu_info bu;
+
+	struct mutex write_reserve_mutex;
+	void *write_reserve_buf;
+
+	int log_lebs;
+	long long log_bytes;
+	int log_last;
+	int lpt_lebs;
+	int lpt_first;
+	int lpt_last;
+	int orph_lebs;
+	int orph_first;
+	int orph_last;
+	int main_lebs;
+	int main_first;
+	long long main_bytes;
+
+	uint8_t key_hash_type;
+	uint32_t (*key_hash)(const char *str, int len);
+	int key_fmt;
+	int key_len;
+	int hash_len;
+	int fanout;
+
+	int min_io_size;
+	int min_io_shift;
+	int max_write_size;
+	int max_write_shift;
+	int leb_size;
+	int leb_start;
+	int half_leb_size;
+	int idx_leb_size;
+	int leb_cnt;
+	int max_leb_cnt;
+	unsigned int ro_media:1;
+	unsigned int ro_mount:1;
+	unsigned int ro_error:1;
+
+	atomic_long_t dirty_pg_cnt;
+	atomic_long_t dirty_zn_cnt;
+	atomic_long_t clean_zn_cnt;
+
+	spinlock_t space_lock;
+	struct ubifs_lp_stats lst;
+	struct ubifs_budg_info bi;
+	unsigned long long calc_idx_sz;
+
+	int ref_node_alsz;
+	int mst_node_alsz;
+	int min_idx_node_sz;
+	int max_idx_node_sz;
+	long long max_inode_sz;
+	int max_znode_sz;
+
+	int leb_overhead;
+	int dead_wm;
+	int dark_wm;
+	int block_cnt;
+
+	struct ubifs_node_range ranges[UBIFS_NODE_TYPES_CNT];
+	struct ubi_volume_desc *ubi;
+	struct ubi_device_info di;
+	struct ubi_volume_info vi;
+
+	struct rb_root orph_tree;
+	struct list_head orph_list;
+	struct list_head orph_new;
+	struct ubifs_orphan *orph_cnext;
+	struct ubifs_orphan *orph_dnext;
+	spinlock_t orphan_lock;
+	void *orph_buf;
+	int new_orphans;
+	int cmt_orphans;
+	int tot_orphans;
+	int max_orphans;
+	int ohead_lnum;
+	int ohead_offs;
+	int no_orphs;
+
+	struct task_struct *bgt;
+	char bgt_name[sizeof(BGT_NAME_PATTERN) + 9];
+	int need_bgt;
+	int need_wbuf_sync;
+
+	int gc_lnum;
+	void *sbuf;
+	struct list_head idx_gc;
+	int idx_gc_cnt;
+	int gc_seq;
+	int gced_lnum;
+
+	struct list_head infos_list;
+	struct mutex umount_mutex;
+	unsigned int shrinker_run_no;
+
+	int space_bits;
+	int lpt_lnum_bits;
+	int lpt_offs_bits;
+	int lpt_spc_bits;
+	int pcnt_bits;
+	int lnum_bits;
+	int nnode_sz;
+	int pnode_sz;
+	int ltab_sz;
+	int lsave_sz;
+	int pnode_cnt;
+	int nnode_cnt;
+	int lpt_hght;
+	int pnodes_have;
+
+	struct mutex lp_mutex;
+	int lpt_lnum;
+	int lpt_offs;
+	int nhead_lnum;
+	int nhead_offs;
+	int lpt_drty_flgs;
+	int dirty_nn_cnt;
+	int dirty_pn_cnt;
+	int check_lpt_free;
+	long long lpt_sz;
+	void *lpt_nod_buf;
+	void *lpt_buf;
+	struct ubifs_nnode *nroot;
+	struct ubifs_cnode *lpt_cnext;
+	struct ubifs_lpt_heap lpt_heap[LPROPS_HEAP_CNT];
+	struct ubifs_lpt_heap dirty_idx;
+	struct list_head uncat_list;
+	struct list_head empty_list;
+	struct list_head freeable_list;
+	struct list_head frdi_idx_list;
+	int freeable_cnt;
+	int in_a_category_cnt;
+
+	int ltab_lnum;
+	int ltab_offs;
+	struct ubifs_lpt_lprops *ltab;
+	struct ubifs_lpt_lprops *ltab_cmt;
+	int lsave_cnt;
+	int lsave_lnum;
+	int lsave_offs;
+	int *lsave;
+	int lscan_lnum;
+
+	long long rp_size;
+	long long report_rp_size;
+	kuid_t rp_uid;
+	kgid_t rp_gid;
+
+	struct crypto_shash *hash_tfm;
+	struct crypto_shash *hmac_tfm;
+	int hmac_desc_len;
+	char *auth_key_name;
+	char *auth_hash_name;
+	enum hash_algo auth_hash_algo;
+
+	struct shash_desc *log_hash;
+
+	/* The below fields are used only during mounting and re-mounting */
+	unsigned int empty:1;
+	unsigned int need_recovery:1;
+	unsigned int replaying:1;
+	unsigned int mounting:1;
+	unsigned int remounting_rw:1;
+	unsigned int probing:1;
+	struct list_head replay_list;
+	struct list_head replay_buds;
+	unsigned long long cs_sqnum;
+	struct list_head unclean_leb_list;
+	struct ubifs_mst_node *rcvrd_mst_node;
+	struct rb_root size_tree;
+	struct ubifs_mount_opts mount_opts;
+
+	struct ubifs_debug_info *dbg;
+	struct ubifs_stats_info *stats;
+};
+
+extern struct list_head ubifs_infos;
+extern spinlock_t ubifs_infos_lock;
+extern atomic_long_t ubifs_clean_zn_cnt;
+extern const struct super_operations ubifs_super_operations;
+extern const struct address_space_operations ubifs_file_address_operations;
+extern const struct file_operations ubifs_file_operations;
+extern const struct inode_operations ubifs_file_inode_operations;
+extern const struct file_operations ubifs_dir_operations;
+extern const struct inode_operations ubifs_dir_inode_operations;
+extern const struct inode_operations ubifs_symlink_inode_operations;
+extern struct ubifs_compressor *ubifs_compressors[UBIFS_COMPR_TYPES_CNT];
+extern int ubifs_default_version;
+
+/* auth.c */
+static inline int ubifs_authenticated(const struct ubifs_info *c)
+{
+	return (IS_ENABLED(CONFIG_UBIFS_FS_AUTHENTICATION)) && c->authenticated;
+}
+
+struct shash_desc *__ubifs_hash_get_desc(const struct ubifs_info *c);
+static inline struct shash_desc *ubifs_hash_get_desc(const struct ubifs_info *c)
+{
+	return ubifs_authenticated(c) ? __ubifs_hash_get_desc(c) : NULL;
+}
+
+static inline int ubifs_shash_init(const struct ubifs_info *c,
+				   struct shash_desc *desc)
+{
+	if (ubifs_authenticated(c))
+		return crypto_shash_init(desc);
+	else
+		return 0;
+}
+
+static inline int ubifs_shash_update(const struct ubifs_info *c,
+				      struct shash_desc *desc, const void *buf,
+				      unsigned int len)
+{
+	int err = 0;
+
+	if (ubifs_authenticated(c)) {
+		err = crypto_shash_update(desc, buf, len);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
+static inline int ubifs_shash_final(const struct ubifs_info *c,
+				    struct shash_desc *desc, u8 *out)
+{
+	return ubifs_authenticated(c) ? crypto_shash_final(desc, out) : 0;
+}
+
+int __ubifs_node_calc_hash(const struct ubifs_info *c, const void *buf,
+			  u8 *hash);
+static inline int ubifs_node_calc_hash(const struct ubifs_info *c,
+					const void *buf, u8 *hash)
+{
+	if (ubifs_authenticated(c))
+		return __ubifs_node_calc_hash(c, buf, hash);
+	else
+		return 0;
+}
+
+int ubifs_prepare_auth_node(struct ubifs_info *c, void *node,
+			     struct shash_desc *inhash);
+
+/**
+ * ubifs_check_hash - compare two hashes
+ * @c: UBIFS file-system description object
+ * @expected: first hash
+ * @got: second hash
+ *
+ * Compare two hashes @expected and @got. Returns 0 when they are equal, a
+ * negative error code otherwise.
+ */
+static inline int ubifs_check_hash(const struct ubifs_info *c,
+				   const u8 *expected, const u8 *got)
+{
+	return crypto_memneq(expected, got, c->hash_len);
+}
+
+/**
+ * ubifs_check_hmac - compare two HMACs
+ * @c: UBIFS file-system description object
+ * @expected: first HMAC
+ * @got: second HMAC
+ *
+ * Compare two hashes @expected and @got. Returns 0 when they are equal, a
+ * negative error code otherwise.
+ */
+static inline int ubifs_check_hmac(const struct ubifs_info *c,
+				   const u8 *expected, const u8 *got)
+{
+	return crypto_memneq(expected, got, c->hmac_desc_len);
+}
+
+#ifdef CONFIG_UBIFS_FS_AUTHENTICATION
+void ubifs_bad_hash(const struct ubifs_info *c, const void *node,
+		    const u8 *hash, int lnum, int offs);
+#else
+static inline void ubifs_bad_hash(const struct ubifs_info *c, const void *node,
+				  const u8 *hash, int lnum, int offs) {};
+#endif
+
+int __ubifs_node_check_hash(const struct ubifs_info *c, const void *buf,
+			  const u8 *expected);
+static inline int ubifs_node_check_hash(const struct ubifs_info *c,
+					const void *buf, const u8 *expected)
+{
+	if (ubifs_authenticated(c))
+		return __ubifs_node_check_hash(c, buf, expected);
+	else
+		return 0;
+}
+
+int ubifs_init_authentication(struct ubifs_info *c);
+void __ubifs_exit_authentication(struct ubifs_info *c);
+static inline void ubifs_exit_authentication(struct ubifs_info *c)
+{
+	if (ubifs_authenticated(c))
+		__ubifs_exit_authentication(c);
+}
+
+/**
+ * ubifs_branch_hash - returns a pointer to the hash of a branch
+ * @c: UBIFS file-system description object
+ * @br: branch to get the hash from
+ *
+ * This returns a pointer to the hash of a branch. Since the key already is a
+ * dynamically sized object we cannot use a struct member here.
+ */
+static inline u8 *ubifs_branch_hash(struct ubifs_info *c,
+				    struct ubifs_branch *br)
+{
+	return (void *)br + sizeof(*br) + c->key_len;
+}
+
+/**
+ * ubifs_copy_hash - copy a hash
+ * @c: UBIFS file-system description object
+ * @from: source hash
+ * @to: destination hash
+ *
+ * With authentication this copies a hash, otherwise does nothing.
+ */
+static inline void ubifs_copy_hash(const struct ubifs_info *c, const u8 *from,
+				   u8 *to)
+{
+	if (ubifs_authenticated(c))
+		memcpy(to, from, c->hash_len);
+}
+
+int __ubifs_node_insert_hmac(const struct ubifs_info *c, void *buf,
+			      int len, int ofs_hmac);
+static inline int ubifs_node_insert_hmac(const struct ubifs_info *c, void *buf,
+					  int len, int ofs_hmac)
+{
+	if (ubifs_authenticated(c))
+		return __ubifs_node_insert_hmac(c, buf, len, ofs_hmac);
+	else
+		return 0;
+}
+
+int __ubifs_node_verify_hmac(const struct ubifs_info *c, const void *buf,
+			     int len, int ofs_hmac);
+static inline int ubifs_node_verify_hmac(const struct ubifs_info *c,
+					 const void *buf, int len, int ofs_hmac)
+{
+	if (ubifs_authenticated(c))
+		return __ubifs_node_verify_hmac(c, buf, len, ofs_hmac);
+	else
+		return 0;
+}
+
+/**
+ * ubifs_auth_node_sz - returns the size of an authentication node
+ * @c: UBIFS file-system description object
+ *
+ * This function returns the size of an authentication node which can
+ * be 0 for unauthenticated filesystems or the real size of an auth node
+ * authentication is enabled.
+ */
+static inline int ubifs_auth_node_sz(const struct ubifs_info *c)
+{
+	if (ubifs_authenticated(c))
+		return sizeof(struct ubifs_auth_node) + c->hmac_desc_len;
+	else
+		return 0;
+}
+int ubifs_sb_verify_signature(struct ubifs_info *c,
+			      const struct ubifs_sb_node *sup);
+bool ubifs_hmac_zero(struct ubifs_info *c, const u8 *hmac);
+
+int ubifs_hmac_wkm(struct ubifs_info *c, u8 *hmac);
+
+int __ubifs_shash_copy_state(const struct ubifs_info *c, struct shash_desc *src,
+			     struct shash_desc *target);
+static inline int ubifs_shash_copy_state(const struct ubifs_info *c,
+					   struct shash_desc *src,
+					   struct shash_desc *target)
+{
+	if (ubifs_authenticated(c))
+		return __ubifs_shash_copy_state(c, src, target);
+	else
+		return 0;
+}
+
+/* io.c */
+void ubifs_ro_mode(struct ubifs_info *c, int err);
+int ubifs_leb_read(const struct ubifs_info *c, int lnum, void *buf, int offs,
+		   int len, int even_ebadmsg);
+int ubifs_leb_write(struct ubifs_info *c, int lnum, const void *buf, int offs,
+		    int len);
+int ubifs_leb_change(struct ubifs_info *c, int lnum, const void *buf, int len);
+int ubifs_leb_unmap(struct ubifs_info *c, int lnum);
+int ubifs_leb_map(struct ubifs_info *c, int lnum);
+int ubifs_is_mapped(const struct ubifs_info *c, int lnum);
+int ubifs_wbuf_write_nolock(struct ubifs_wbuf *wbuf, void *buf, int len);
+int ubifs_wbuf_seek_nolock(struct ubifs_wbuf *wbuf, int lnum, int offs);
+int ubifs_wbuf_init(struct ubifs_info *c, struct ubifs_wbuf *wbuf);
+int ubifs_read_node(const struct ubifs_info *c, void *buf, int type, int len,
+		    int lnum, int offs);
+int ubifs_read_node_wbuf(struct ubifs_wbuf *wbuf, void *buf, int type, int len,
+			 int lnum, int offs);
+int ubifs_write_node(struct ubifs_info *c, void *node, int len, int lnum,
+		     int offs);
+int ubifs_write_node_hmac(struct ubifs_info *c, void *buf, int len, int lnum,
+			  int offs, int hmac_offs);
+int ubifs_check_node(const struct ubifs_info *c, const void *buf, int len,
+		     int lnum, int offs, int quiet, int must_chk_crc);
+void ubifs_init_node(struct ubifs_info *c, void *buf, int len, int pad);
+void ubifs_crc_node(struct ubifs_info *c, void *buf, int len);
+void ubifs_prepare_node(struct ubifs_info *c, void *buf, int len, int pad);
+int ubifs_prepare_node_hmac(struct ubifs_info *c, void *node, int len,
+			    int hmac_offs, int pad);
+void ubifs_prep_grp_node(struct ubifs_info *c, void *node, int len, int last);
+int ubifs_io_init(struct ubifs_info *c);
+void ubifs_pad(const struct ubifs_info *c, void *buf, int pad);
+int ubifs_wbuf_sync_nolock(struct ubifs_wbuf *wbuf);
+int ubifs_bg_wbufs_sync(struct ubifs_info *c);
+void ubifs_wbuf_add_ino_nolock(struct ubifs_wbuf *wbuf, ino_t inum);
+int ubifs_sync_wbufs_by_inode(struct ubifs_info *c, struct inode *inode);
+
+/* scan.c */
+struct ubifs_scan_leb *ubifs_scan(const struct ubifs_info *c, int lnum,
+				  int offs, void *sbuf, int quiet);
+void ubifs_scan_destroy(struct ubifs_scan_leb *sleb);
+int ubifs_scan_a_node(const struct ubifs_info *c, void *buf, int len, int lnum,
+		      int offs, int quiet);
+struct ubifs_scan_leb *ubifs_start_scan(const struct ubifs_info *c, int lnum,
+					int offs, void *sbuf);
+void ubifs_end_scan(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
+		    int lnum, int offs);
+int ubifs_add_snod(const struct ubifs_info *c, struct ubifs_scan_leb *sleb,
+		   void *buf, int offs);
+void ubifs_scanned_corruption(const struct ubifs_info *c, int lnum, int offs,
+			      void *buf);
+
+/* log.c */
+void ubifs_add_bud(struct ubifs_info *c, struct ubifs_bud *bud);
+void ubifs_create_buds_lists(struct ubifs_info *c);
+int ubifs_add_bud_to_log(struct ubifs_info *c, int jhead, int lnum, int offs);
+struct ubifs_bud *ubifs_search_bud(struct ubifs_info *c, int lnum);
+struct ubifs_wbuf *ubifs_get_wbuf(struct ubifs_info *c, int lnum);
+int ubifs_log_start_commit(struct ubifs_info *c, int *ltail_lnum);
+int ubifs_log_end_commit(struct ubifs_info *c, int new_ltail_lnum);
+int ubifs_log_post_commit(struct ubifs_info *c, int old_ltail_lnum);
+int ubifs_consolidate_log(struct ubifs_info *c);
+
+/* journal.c */
+int ubifs_jnl_update(struct ubifs_info *c, const struct inode *dir,
+		     const struct fscrypt_name *nm, const struct inode *inode,
+		     int deletion, int xent);
+int ubifs_jnl_write_data(struct ubifs_info *c, const struct inode *inode,
+			 const union ubifs_key *key, const void *buf, int len);
+int ubifs_jnl_write_inode(struct ubifs_info *c, const struct inode *inode);
+int ubifs_jnl_delete_inode(struct ubifs_info *c, const struct inode *inode);
+int ubifs_jnl_xrename(struct ubifs_info *c, const struct inode *fst_dir,
+		      const struct inode *fst_inode,
+		      const struct fscrypt_name *fst_nm,
+		      const struct inode *snd_dir,
+		      const struct inode *snd_inode,
+		      const struct fscrypt_name *snd_nm, int sync);
+int ubifs_jnl_rename(struct ubifs_info *c, const struct inode *old_dir,
+		     const struct inode *old_inode,
+		     const struct fscrypt_name *old_nm,
+		     const struct inode *new_dir,
+		     const struct inode *new_inode,
+		     const struct fscrypt_name *new_nm,
+		     const struct inode *whiteout, int sync);
+int ubifs_jnl_truncate(struct ubifs_info *c, const struct inode *inode,
+		       loff_t old_size, loff_t new_size);
+int ubifs_jnl_delete_xattr(struct ubifs_info *c, const struct inode *host,
+			   const struct inode *inode, const struct fscrypt_name *nm);
+int ubifs_jnl_change_xattr(struct ubifs_info *c, const struct inode *inode1,
+			   const struct inode *inode2);
+
+/* budget.c */
+int ubifs_budget_space(struct ubifs_info *c, struct ubifs_budget_req *req);
+void ubifs_release_budget(struct ubifs_info *c, struct ubifs_budget_req *req);
+void ubifs_release_dirty_inode_budget(struct ubifs_info *c,
+				      struct ubifs_inode *ui);
+int ubifs_budget_inode_op(struct ubifs_info *c, struct inode *inode,
+			  struct ubifs_budget_req *req);
+void ubifs_release_ino_dirty(struct ubifs_info *c, struct inode *inode,
+				struct ubifs_budget_req *req);
+void ubifs_cancel_ino_op(struct ubifs_info *c, struct inode *inode,
+			 struct ubifs_budget_req *req);
+long long ubifs_get_free_space(struct ubifs_info *c);
+long long ubifs_get_free_space_nolock(struct ubifs_info *c);
+int ubifs_calc_min_idx_lebs(struct ubifs_info *c);
+void ubifs_convert_page_budget(struct ubifs_info *c);
+long long ubifs_reported_space(const struct ubifs_info *c, long long free);
+long long ubifs_calc_available(const struct ubifs_info *c, int min_idx_lebs);
+
+/* find.c */
+int ubifs_find_free_space(struct ubifs_info *c, int min_space, int *offs,
+			  int squeeze);
+int ubifs_find_free_leb_for_idx(struct ubifs_info *c);
+int ubifs_find_dirty_leb(struct ubifs_info *c, struct ubifs_lprops *ret_lp,
+			 int min_space, int pick_free);
+int ubifs_find_dirty_idx_leb(struct ubifs_info *c);
+int ubifs_save_dirty_idx_lnums(struct ubifs_info *c);
+
+/* tnc.c */
+int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
+			struct ubifs_znode **zn, int *n);
+int ubifs_tnc_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
+			void *node, const struct fscrypt_name *nm);
+int ubifs_tnc_lookup_dh(struct ubifs_info *c, const union ubifs_key *key,
+			void *node, uint32_t secondary_hash);
+int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key,
+		     void *node, int *lnum, int *offs);
+int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum,
+		  int offs, int len, const u8 *hash);
+int ubifs_tnc_replace(struct ubifs_info *c, const union ubifs_key *key,
+		      int old_lnum, int old_offs, int lnum, int offs, int len);
+int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
+		     int lnum, int offs, int len, const u8 *hash,
+		     const struct fscrypt_name *nm);
+int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key);
+int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
+			const struct fscrypt_name *nm);
+int ubifs_tnc_remove_dh(struct ubifs_info *c, const union ubifs_key *key,
+			uint32_t cookie);
+int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key,
+			   union ubifs_key *to_key);
+int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum);
+struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c,
+					   union ubifs_key *key,
+					   const struct fscrypt_name *nm);
+void ubifs_tnc_close(struct ubifs_info *c);
+int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level,
+		       int lnum, int offs, int is_idx);
+int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level,
+			 int lnum, int offs);
+/* Shared by tnc.c for tnc_commit.c */
+void destroy_old_idx(struct ubifs_info *c);
+int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level,
+		       int lnum, int offs);
+int insert_old_idx_znode(struct ubifs_info *c, struct ubifs_znode *znode);
+int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu);
+int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu);
+
+/* tnc_misc.c */
+struct ubifs_znode *ubifs_tnc_levelorder_next(const struct ubifs_info *c,
+					      struct ubifs_znode *zr,
+					      struct ubifs_znode *znode);
+int ubifs_search_zbranch(const struct ubifs_info *c,
+			 const struct ubifs_znode *znode,
+			 const union ubifs_key *key, int *n);
+struct ubifs_znode *ubifs_tnc_postorder_first(struct ubifs_znode *znode);
+struct ubifs_znode *ubifs_tnc_postorder_next(const struct ubifs_info *c,
+					     struct ubifs_znode *znode);
+long ubifs_destroy_tnc_subtree(const struct ubifs_info *c,
+			       struct ubifs_znode *zr);
+void ubifs_destroy_tnc_tree(struct ubifs_info *c);
+struct ubifs_znode *ubifs_load_znode(struct ubifs_info *c,
+				     struct ubifs_zbranch *zbr,
+				     struct ubifs_znode *parent, int iip);
+int ubifs_tnc_read_node(struct ubifs_info *c, struct ubifs_zbranch *zbr,
+			void *node);
+
+/* tnc_commit.c */
+int ubifs_tnc_start_commit(struct ubifs_info *c, struct ubifs_zbranch *zroot);
+int ubifs_tnc_end_commit(struct ubifs_info *c);
+
+/* shrinker.c */
+unsigned long ubifs_shrink_scan(struct shrinker *shrink,
+				struct shrink_control *sc);
+unsigned long ubifs_shrink_count(struct shrinker *shrink,
+				 struct shrink_control *sc);
+
+/* commit.c */
+int ubifs_bg_thread(void *info);
+void ubifs_commit_required(struct ubifs_info *c);
+void ubifs_request_bg_commit(struct ubifs_info *c);
+int ubifs_run_commit(struct ubifs_info *c);
+void ubifs_recovery_commit(struct ubifs_info *c);
+int ubifs_gc_should_commit(struct ubifs_info *c);
+void ubifs_wait_for_commit(struct ubifs_info *c);
+
+/* master.c */
+int ubifs_compare_master_node(struct ubifs_info *c, void *m1, void *m2);
+int ubifs_read_master(struct ubifs_info *c);
+int ubifs_write_master(struct ubifs_info *c);
+
+/* sb.c */
+int ubifs_read_superblock(struct ubifs_info *c);
+int ubifs_write_sb_node(struct ubifs_info *c, struct ubifs_sb_node *sup);
+int ubifs_fixup_free_space(struct ubifs_info *c);
+int ubifs_enable_encryption(struct ubifs_info *c);
+
+/* replay.c */
+int ubifs_validate_entry(struct ubifs_info *c,
+			 const struct ubifs_dent_node *dent);
+int ubifs_replay_journal(struct ubifs_info *c);
+
+/* gc.c */
+int ubifs_garbage_collect(struct ubifs_info *c, int anyway);
+int ubifs_gc_start_commit(struct ubifs_info *c);
+int ubifs_gc_end_commit(struct ubifs_info *c);
+void ubifs_destroy_idx_gc(struct ubifs_info *c);
+int ubifs_get_idx_gc_leb(struct ubifs_info *c);
+int ubifs_garbage_collect_leb(struct ubifs_info *c, struct ubifs_lprops *lp);
+
+/* orphan.c */
+int ubifs_add_orphan(struct ubifs_info *c, ino_t inum);
+void ubifs_delete_orphan(struct ubifs_info *c, ino_t inum);
+int ubifs_orphan_start_commit(struct ubifs_info *c);
+int ubifs_orphan_end_commit(struct ubifs_info *c);
+int ubifs_mount_orphans(struct ubifs_info *c, int unclean, int read_only);
+int ubifs_clear_orphans(struct ubifs_info *c);
+
+/* lpt.c */
+int ubifs_calc_lpt_geom(struct ubifs_info *c);
+int ubifs_create_lpt(struct ubifs_info *c, struct ubifs_lprops *lps, int lp_cnt,
+		     u8 *hash);
+int ubifs_create_dflt_lpt(struct ubifs_info *c, int *main_lebs, int lpt_first,
+			  int *lpt_lebs, int *big_lpt, u8 *hash);
+int ubifs_lpt_init(struct ubifs_info *c, int rd, int wr);
+struct ubifs_lprops *ubifs_lpt_lookup(struct ubifs_info *c, int lnum);
+struct ubifs_lprops *ubifs_lpt_lookup_dirty(struct ubifs_info *c, int lnum);
+int ubifs_lpt_scan_nolock(struct ubifs_info *c, int start_lnum, int end_lnum,
+			  ubifs_lpt_scan_callback scan_cb, void *data);
+
+/* Shared by lpt.c for lpt_commit.c */
+void ubifs_pack_lsave(struct ubifs_info *c, void *buf, int *lsave);
+void ubifs_pack_ltab(struct ubifs_info *c, void *buf,
+		     struct ubifs_lpt_lprops *ltab);
+void ubifs_pack_pnode(struct ubifs_info *c, void *buf,
+		      struct ubifs_pnode *pnode);
+void ubifs_pack_nnode(struct ubifs_info *c, void *buf,
+		      struct ubifs_nnode *nnode);
+struct ubifs_pnode *ubifs_get_pnode(struct ubifs_info *c,
+				    struct ubifs_nnode *parent, int iip);
+struct ubifs_nnode *ubifs_get_nnode(struct ubifs_info *c,
+				    struct ubifs_nnode *parent, int iip);
+struct ubifs_pnode *ubifs_pnode_lookup(struct ubifs_info *c, int i);
+int ubifs_read_nnode(struct ubifs_info *c, struct ubifs_nnode *parent, int iip);
+void ubifs_add_lpt_dirt(struct ubifs_info *c, int lnum, int dirty);
+void ubifs_add_nnode_dirt(struct ubifs_info *c, struct ubifs_nnode *nnode);
+uint32_t ubifs_unpack_bits(const struct ubifs_info *c, uint8_t **addr, int *pos, int nrbits);
+struct ubifs_nnode *ubifs_first_nnode(struct ubifs_info *c, int *hght);
+/* Needed only in debugging code in lpt_commit.c */
+int ubifs_unpack_nnode(const struct ubifs_info *c, void *buf,
+		       struct ubifs_nnode *nnode);
+int ubifs_lpt_calc_hash(struct ubifs_info *c, u8 *hash);
+
+/* lpt_commit.c */
+int ubifs_lpt_start_commit(struct ubifs_info *c);
+int ubifs_lpt_end_commit(struct ubifs_info *c);
+int ubifs_lpt_post_commit(struct ubifs_info *c);
+void ubifs_lpt_free(struct ubifs_info *c, int wr_only);
+
+/* lprops.c */
+const struct ubifs_lprops *ubifs_change_lp(struct ubifs_info *c,
+					   const struct ubifs_lprops *lp,
+					   int free, int dirty, int flags,
+					   int idx_gc_cnt);
+void ubifs_get_lp_stats(struct ubifs_info *c, struct ubifs_lp_stats *lst);
+void ubifs_add_to_cat(struct ubifs_info *c, struct ubifs_lprops *lprops,
+		      int cat);
+void ubifs_replace_cat(struct ubifs_info *c, struct ubifs_lprops *old_lprops,
+		       struct ubifs_lprops *new_lprops);
+void ubifs_ensure_cat(struct ubifs_info *c, struct ubifs_lprops *lprops);
+int ubifs_categorize_lprops(const struct ubifs_info *c,
+			    const struct ubifs_lprops *lprops);
+int ubifs_change_one_lp(struct ubifs_info *c, int lnum, int free, int dirty,
+			int flags_set, int flags_clean, int idx_gc_cnt);
+int ubifs_update_one_lp(struct ubifs_info *c, int lnum, int free, int dirty,
+			int flags_set, int flags_clean);
+int ubifs_read_one_lp(struct ubifs_info *c, int lnum, struct ubifs_lprops *lp);
+const struct ubifs_lprops *ubifs_fast_find_free(struct ubifs_info *c);
+const struct ubifs_lprops *ubifs_fast_find_empty(struct ubifs_info *c);
+const struct ubifs_lprops *ubifs_fast_find_freeable(struct ubifs_info *c);
+const struct ubifs_lprops *ubifs_fast_find_frdi_idx(struct ubifs_info *c);
+int ubifs_calc_dark(const struct ubifs_info *c, int spc);
+
+/* file.c */
+int ubifs_fsync(struct file *file, loff_t start, loff_t end, int datasync);
+int ubifs_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+		  struct iattr *attr);
+int ubifs_update_time(struct inode *inode, int flags);
+
+/* dir.c */
+struct inode *ubifs_new_inode(struct ubifs_info *c, struct inode *dir,
+			      umode_t mode, bool is_xattr);
+int ubifs_getattr(struct mnt_idmap *idmap, const struct path *path,
+		  struct kstat *stat, u32 request_mask, unsigned int flags);
+int ubifs_check_dir_empty(struct inode *dir);
+
+/* xattr.c */
+int ubifs_xattr_set(struct inode *host, const char *name, const void *value,
+		    size_t size, int flags, bool check_lock);
+ssize_t ubifs_xattr_get(struct inode *host, const char *name, void *buf,
+			size_t size);
+
+#ifdef CONFIG_UBIFS_FS_XATTR
+extern const struct xattr_handler * const ubifs_xattr_handlers[];
+ssize_t ubifs_listxattr(struct dentry *dentry, char *buffer, size_t size);
+void ubifs_evict_xattr_inode(struct ubifs_info *c, ino_t xattr_inum);
+int ubifs_purge_xattrs(struct inode *host);
+#else
+#define ubifs_listxattr NULL
+#define ubifs_xattr_handlers NULL
+static inline void ubifs_evict_xattr_inode(struct ubifs_info *c,
+					   ino_t xattr_inum) { }
+static inline int ubifs_purge_xattrs(struct inode *host)
+{
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_UBIFS_FS_SECURITY
+extern int ubifs_init_security(struct inode *dentry, struct inode *inode,
+			const struct qstr *qstr);
+#else
+static inline int ubifs_init_security(struct inode *dentry,
+			struct inode *inode, const struct qstr *qstr)
+{
+	return 0;
+}
+#endif
+
+
+/* super.c */
+struct inode *ubifs_iget(struct super_block *sb, unsigned long inum);
+
+/* recovery.c */
+int ubifs_recover_master_node(struct ubifs_info *c);
+int ubifs_write_rcvrd_mst_node(struct ubifs_info *c);
+struct ubifs_scan_leb *ubifs_recover_leb(struct ubifs_info *c, int lnum,
+					 int offs, void *sbuf, int jhead);
+struct ubifs_scan_leb *ubifs_recover_log_leb(struct ubifs_info *c, int lnum,
+					     int offs, void *sbuf);
+int ubifs_recover_inl_heads(struct ubifs_info *c, void *sbuf);
+int ubifs_clean_lebs(struct ubifs_info *c, void *sbuf);
+int ubifs_rcvry_gc_commit(struct ubifs_info *c);
+int ubifs_recover_size_accum(struct ubifs_info *c, union ubifs_key *key,
+			     int deletion, loff_t new_size);
+int ubifs_recover_size(struct ubifs_info *c, bool in_place);
+void ubifs_destroy_size_tree(struct ubifs_info *c);
+
+/* ioctl.c */
+int ubifs_fileattr_get(struct dentry *dentry, struct fileattr *fa);
+int ubifs_fileattr_set(struct mnt_idmap *idmap,
+		       struct dentry *dentry, struct fileattr *fa);
+long ubifs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
+void ubifs_set_inode_flags(struct inode *inode);
+#ifdef CONFIG_COMPAT
+long ubifs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
+#endif
+
+/* compressor.c */
+int __init ubifs_compressors_init(void);
+void ubifs_compressors_exit(void);
+void ubifs_compress(const struct ubifs_info *c, const void *in_buf, int in_len,
+		    void *out_buf, int *out_len, int *compr_type);
+int ubifs_decompress(const struct ubifs_info *c, const void *buf, int len,
+		     void *out, int *out_len, int compr_type);
+
+/* sysfs.c */
+int ubifs_sysfs_init(void);
+void ubifs_sysfs_exit(void);
+int ubifs_sysfs_register(struct ubifs_info *c);
+void ubifs_sysfs_unregister(struct ubifs_info *c);
+
+#include "debug.h"
+#include "misc.h"
+#include "key.h"
+
+#ifndef CONFIG_FS_ENCRYPTION
+static inline int ubifs_encrypt(const struct inode *inode,
+				struct ubifs_data_node *dn,
+				unsigned int in_len, unsigned int *out_len,
+				int block)
+{
+	struct ubifs_info *c = inode->i_sb->s_fs_info;
+	ubifs_assert(c, 0);
+	return -EOPNOTSUPP;
+}
+static inline int ubifs_decrypt(const struct inode *inode,
+				struct ubifs_data_node *dn,
+				unsigned int *out_len, int block)
+{
+	struct ubifs_info *c = inode->i_sb->s_fs_info;
+	ubifs_assert(c, 0);
+	return -EOPNOTSUPP;
+}
+#else
+/* crypto.c */
+int ubifs_encrypt(const struct inode *inode, struct ubifs_data_node *dn,
+		  unsigned int in_len, unsigned int *out_len, int block);
+int ubifs_decrypt(const struct inode *inode, struct ubifs_data_node *dn,
+		  unsigned int *out_len, int block);
+#endif
+
+extern const struct fscrypt_operations ubifs_crypt_operations;
+
+/* Normal UBIFS messages */
+__printf(2, 3)
+void ubifs_msg(const struct ubifs_info *c, const char *fmt, ...);
+__printf(2, 3)
+void ubifs_err(const struct ubifs_info *c, const char *fmt, ...);
+__printf(2, 3)
+void ubifs_warn(const struct ubifs_info *c, const char *fmt, ...);
+/*
+ * A conditional variant of 'ubifs_err()' which doesn't output anything
+ * if probing (ie. SB_SILENT set).
+ */
+#define ubifs_errc(c, fmt, ...)						\
+do {									\
+	if (!(c)->probing)						\
+		ubifs_err(c, fmt, ##__VA_ARGS__);			\
+} while (0)
+
+#endif /* !__UBIFS_H__ */
-- 
2.13.6