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Diffstat (limited to 'fs/ubifs/key.h')
| -rw-r--r-- | fs/ubifs/key.h | 533 |
1 files changed, 533 insertions, 0 deletions
diff --git a/fs/ubifs/key.h b/fs/ubifs/key.h new file mode 100644 index 000000000000..8f7476007549 --- /dev/null +++ b/fs/ubifs/key.h @@ -0,0 +1,533 @@ +/* + * 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++; + } + + a &= UBIFS_S_KEY_HASH_MASK; + + /* + * 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. + */ + 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); + a &= UBIFS_S_KEY_HASH_MASK; + 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 << 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 + */ +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); + + ubifs_assert(!(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(!(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 qstr *nm) +{ + union ubifs_key *key = k; + uint32_t hash = c->key_hash(nm->name, nm->len); + + ubifs_assert(!(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 qstr *nm) +{ + uint32_t hash = c->key_hash(nm->name, nm->len); + + ubifs_assert(!(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_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) +{ + ubifs_assert(!(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 qstr *nm) +{ + union ubifs_key *key = k; + uint32_t hash = c->key_hash(nm->name, nm->len); + + ubifs_assert(!(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(!(block & ~UBIFS_S_KEY_BLOCK_MASK)); + key->u32[0] = inum; + key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS); +} + +/** + * 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; + + ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK)); + key->j32[0] = cpu_to_le32(inum); + key->j32[1] = cpu_to_le32(block | + (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS)); + 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 + * + * 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; +} + +/** + * 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->u32[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 int 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 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]) & 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->u32[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; +} + +/** + * 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__ */ |