Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932857AbcLAWC4 (ORCPT ); Thu, 1 Dec 2016 17:02:56 -0500 Received: from mail.sigma-star.at ([95.130.255.111]:45999 "EHLO mail.sigma-star.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761082AbcLAWCn (ORCPT ); Thu, 1 Dec 2016 17:02:43 -0500 From: Richard Weinberger To: linux-mtd@lists.infradead.org Cc: david@sigma-star.at, tytso@mit.edu, dedekind1@gmail.com, adrian.hunter@intel.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, adilger.kernel@dilger.ca, akpm@linux-foundation.org, linux-ext4@vger.kernel.org, Richard Weinberger Subject: [PATCH 3/6] ubifs: Use 64bit readdir cookies Date: Thu, 1 Dec 2016 23:02:18 +0100 Message-Id: <1480629741-18375-4-git-send-email-richard@nod.at> X-Mailer: git-send-email 2.7.3 In-Reply-To: <1480629741-18375-1-git-send-email-richard@nod.at> References: <1480629741-18375-1-git-send-email-richard@nod.at> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5363 Lines: 180 This is the first step to support proper telldir/seekdir() in UBIFS. Let's report 64bit cookies in readdir(). The cookie is a combination of the entry key plus the double hash value. Signed-off-by: Richard Weinberger --- fs/ubifs/dir.c | 46 +++++++++++++++++++++++++++++++------------ fs/ubifs/key.h | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ fs/ubifs/ubifs.h | 1 + 3 files changed, 94 insertions(+), 12 deletions(-) diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index 883b2fdf51df..3b8c08dad75b 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -539,7 +539,7 @@ static int ubifs_readdir(struct file *file, struct dir_context *ctx) dbg_gen("dir ino %lu, f_pos %#llx", dir->i_ino, ctx->pos); - if (ctx->pos > UBIFS_S_KEY_HASH_MASK || ctx->pos == 2) + if (ctx->pos == 2) /* * The directory was seek'ed to a senseless position or there * are no more entries. @@ -594,7 +594,7 @@ static int ubifs_readdir(struct file *file, struct dir_context *ctx) goto out; } - ctx->pos = key_hash_flash(c, &dent->key); + ctx->pos = key_get_dir_pos(c, file, dent); file->private_data = dent; } @@ -604,21 +604,43 @@ static int ubifs_readdir(struct file *file, struct dir_context *ctx) * 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; + dent_key_init_hash(c, &key, dir->i_ino, + key_get_hash_from_dir_pos(c, file, ctx->pos)); + + if (key_want_short_hash(file)) { + err = -ENOENT; + } else { + dent = kmalloc(UBIFS_MAX_DENT_NODE_SZ, GFP_NOFS); + if (!dent) { + err = -ENOMEM; + goto out; + } + + err = ubifs_tnc_lookup_dh(c, &key, dent, + key_get_cookie_from_dir_pos(c, ctx->pos)); + } + if (err) { + kfree(dent); + + if (err < 0 && err != -ENOENT && err != -EOPNOTSUPP) + goto out; + + 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); + + ctx->pos = key_get_dir_pos(c, file, dent); file->private_data = dent; } while (1) { - dbg_gen("feed '%s', ino %llu, new f_pos %#x", + dbg_gen("feed '%s', ino %llu, new f_pos %#lx", dent->name, (unsigned long long)le64_to_cpu(dent->inum), - key_hash_flash(c, &dent->key)); + (unsigned long)key_get_dir_pos(c, file, dent)); ubifs_assert(le64_to_cpu(dent->ch.sqnum) > ubifs_inode(dir)->creat_sqnum); @@ -656,7 +678,7 @@ static int ubifs_readdir(struct file *file, struct dir_context *ctx) } kfree(file->private_data); - ctx->pos = key_hash_flash(c, &dent->key); + ctx->pos = key_get_dir_pos(c, file, dent); file->private_data = dent; cond_resched(); } diff --git a/fs/ubifs/key.h b/fs/ubifs/key.h index 7547be512db2..2788e36ce832 100644 --- a/fs/ubifs/key.h +++ b/fs/ubifs/key.h @@ -397,6 +397,65 @@ static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k) } /** + * key_want_short_hash - tests whether we can emit a 64bit hash or not. + * @file: the file handle of the directory + */ +static inline bool key_want_short_hash(struct file *file) +{ + if (file->f_mode & FMODE_32BITHASH) + return true; + + if (!(file->f_mode & FMODE_64BITHASH) && is_32bit_api()) + return true; + + return false; +} + +/** + * key_dir_pos - compute a 64bit directory cookie for readdir() + * @c: UBIFS file-system description object + * @file: the file handle of the directory + * @dent: the directory entry + */ +static inline loff_t key_get_dir_pos(const struct ubifs_info *c, + struct file *file, + struct ubifs_dent_node *dent) +{ + BUILD_BUG_ON(sizeof(loff_t) < 8); + + if (key_want_short_hash(file)) + return key_hash_flash(c, &dent->key); + + return ((loff_t)key_hash_flash(c, &dent->key)) << UBIFS_DH_BITS | le32_to_cpu(dent->cookie); +} + +/** + * key_get_hash_from_dir_pos - extracts the flash key from a directory offset. + * @c: UBIFS file-system description object + * @file: the file handle of the directory + * @pos: the directory offset provied by VFS + */ +static inline uint32_t key_get_hash_from_dir_pos(const struct ubifs_info *c, + struct file *file, loff_t pos) +{ + if (key_want_short_hash(file)) + return pos & UBIFS_S_KEY_HASH_MASK; + + return (pos >> UBIFS_DH_BITS) & UBIFS_S_KEY_HASH_MASK; +} + +/** + * key_get_cookie_from_dir_pos - extracts the double hash cookie from a directory offset. + * @c: UBIFS file-system description object + * @pos: the directory offset provied by VFS + */ +static inline uint32_t key_get_cookie_from_dir_pos(const struct ubifs_info *c, + loff_t pos) +{ + return pos & UBIFS_DH_MASK; +} + +/** * key_block - get data block number. * @c: UBIFS file-system description object * @key: the key to get the block number from diff --git a/fs/ubifs/ubifs.h b/fs/ubifs/ubifs.h index 12f3df3ced0e..0532a6f82b1d 100644 --- a/fs/ubifs/ubifs.h +++ b/fs/ubifs/ubifs.h @@ -40,6 +40,7 @@ #include #include #include +#include #include "ubifs-media.h" /* Version of this UBIFS implementation */ -- 2.7.3