Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762890AbYC0NR3 (ORCPT ); Thu, 27 Mar 2008 09:17:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760804AbYC0NKY (ORCPT ); Thu, 27 Mar 2008 09:10:24 -0400 Received: from smtp.nokia.com ([192.100.122.233]:50106 "EHLO mgw-mx06.nokia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760801AbYC0NKV (ORCPT ); Thu, 27 Mar 2008 09:10:21 -0400 From: Artem Bityutskiy To: LKML Cc: Adrian Hunter , Artem Bityutskiy Subject: [RFC PATCH 09/26] UBIFS: add key helpers Date: Thu, 27 Mar 2008 16:55:29 +0200 Message-Id: <1206629746-4298-10-git-send-email-Artem.Bityutskiy@nokia.com> X-Mailer: git-send-email 1.5.4.1 In-Reply-To: <1206629746-4298-1-git-send-email-Artem.Bityutskiy@nokia.com> References: <1206629746-4298-1-git-send-email-Artem.Bityutskiy@nokia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=unknown-8bit Content-Transfer-Encoding: 8bit X-OriginalArrivalTime: 27 Mar 2008 13:06:30.0748 (UTC) FILETIME=[5FDDF1C0:01C8900B] X-Nokia-AV: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 14798 Lines: 532 This file implement various helper functions to work with UBIFS keys. The keys are part of the UBIFS index which is a B-tree. For example, directory entry key consists of the parent inode number and directory entry hash. Signed-off-by: Artem Bityutskiy Signed-off-by: Adrian Hunter --- fs/ubifs/key.h | 507 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 507 insertions(+), 0 deletions(-) diff --git a/fs/ubifs/key.h b/fs/ubifs/key.h new file mode 100644 index 0000000..679cb80 --- /dev/null +++ b/fs/ubifs/key.h @@ -0,0 +1,507 @@ +/* + * This file is part of UBIFS. + * + * Copyright (C) 2006-2008 Nokia Corporation. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., 51 + * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + * 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. + */ + +#ifndef __UBIFS_KEY_H__ +#define __UBIFS_KEY_H__ + +/** + * 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 (*str) { + a += *str << 4; + a += *str >> 4; + a *= 11; + str++; + } + + /* + * We use hash values as offset in directories, so offsets 0 and 1 are + * reserved for "." and "..". Offset 2 is also reserved for readdir() + * purposes. + */ + if (unlikely(a >= 0 && a <= 2)) + a += 3; + return 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); + if (unlikely(a >= 0 && a <= 2)) + a += 3; + return 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 << 29; +} + +/** + * 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 << 29); + 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 + */ +static inline void dent_key_init(const struct ubifs_info *c, + union ubifs_key *key, ino_t inum, + const struct qstr *nm) +{ + uint32_t hash = c->key_hash(nm->name, nm->len); + + key->u32[0] = inum; + key->u32[1] = (hash & 0x01FFFFFF) | (UBIFS_DENT_KEY << 29); +} + +/** + * 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) +{ + key->u32[0] = inum; + key->u32[1] = (hash & 0x01FFFFFF) | (UBIFS_DENT_KEY << 29); +} + +/** + * 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 qstr *nm) +{ + union ubifs_key *key = k; + uint32_t hash = c->key_hash(nm->name, nm->len); + + key->j32[0] = cpu_to_le32(inum); + key->j32[1] = cpu_to_le32((hash & 0x01FFFFFF) | (UBIFS_DENT_KEY << 29)); + 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 << 29; +} + +/** + * 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 qstr *nm) +{ + uint32_t hash = c->key_hash(nm->name, nm->len); + + key->u32[0] = inum; + key->u32[1] = (hash & 0x01FFFFFF) | (UBIFS_XENT_KEY << 29); +} + +/** + * xent_key_init_hash - initialize extended attribute entry key without + * re-calculating hash function. + * @c: UBIFS file-system description object + * @key: key to initialize + * @inum: host inode number + * @hash: extended attribute entry name hash + */ +static inline void xent_key_init_hash(const struct ubifs_info *c, + union ubifs_key *key, ino_t inum, + uint32_t hash) +{ + key->u32[0] = inum; + key->u32[1] = (hash & 0x01FFFFFF) | (UBIFS_XENT_KEY << 29); +} + +/** + * 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 qstr *nm) +{ + union ubifs_key *key = k; + uint32_t hash = c->key_hash(nm->name, nm->len); + + key->j32[0] = cpu_to_le32(inum); + key->j32[1] = cpu_to_le32((hash & 0x01FFFFFF) | (UBIFS_XENT_KEY << 29)); + 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 << 29; +} + +/** + * 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) +{ + key->u32[0] = inum; + key->u32[1] = (block & 0x01FFFFFF) | (UBIFS_DATA_KEY << 29); +} + +/** + * data_key_init_flash - initialize on-flash data key. + * @c: UBIFS file-system description object + * @k: key to initialize + * @inum: inode number + * @block: block number + */ +static inline void data_key_init_flash(const struct ubifs_info *c, void *k, + ino_t inum, unsigned int block) +{ + union ubifs_key *key = k; + + key->j32[0] = cpu_to_le32(inum); + key->j32[1] = cpu_to_le32((block & 0x01FFFFFF) | + (UBIFS_DATA_KEY << 29)); + memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8); +} + +/** + * trun_key_init - initialize truncation node key. + * @c: UBIFS file-system description object + * @key: key to initialize + * @inum: inode number + */ +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 << 29; +} + +/** + * trun_key_init_flash - initialize on-flash truncation node key. + * @c: UBIFS file-system description object + * @k: key to initialize + * @inum: inode number + */ +static inline void trun_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_TRUN_KEY << 29); + memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8); +} + +/** + * 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] >> 29; +} + +/** + * 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->u32[1]) >> 29; +} + +/** + * key_ino - fetch inode number from key. + * @c: UBIFS file-system description object + * @k: key to fetch inode number from + */ +static inline ino_t key_ino(const struct ubifs_info *c, const void *k) +{ + const union ubifs_key *key = k; + + return key->u32[0]; +} + +/** + * key_ino_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_ino_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 int key_hash(const struct ubifs_info *c, + const union ubifs_key *key) +{ + return key->u32[1] & 0x01FFFFFF; +} + +/** + * 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 int key_hash_flash(const struct ubifs_info *c, const void *k) +{ + const union ubifs_key *key = k; + + return le32_to_cpu(key->j32[1]) & 0x01FFFFFF; +} + +/** + * 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] & 0x01FFFFFF; +} + +/** + * 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 then + * @key2, 0 if the keys are equivalent and %1 if @key1 is greater then @key2. + */ +static inline int keys_cmp(const struct ubifs_info *c, + const union ubifs_key *key1, + const union ubifs_key *key2) +{ + int i; + + for (i = 0; i < 2; i++) { + if (key1->u32[i] < key2->u32[i]) + return -1; + if (key1->u32[i] > key2->u32[i]) + return 1; + } + + return 0; +} + +/** + * 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; +} + +#endif /* !__UBIFS_KEY_H__ */ -- 1.5.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/