Merge branch 'kvm-updates/2.6.33' of git://git.kernel.org/pub/scm/virt/kvm/kvm
[linux-2.6/linux-2.6-openrd.git] / fs / ubifs / key.h
blob0f530c684f0ba13c99c1424c6614d54f0f3ae23b
1 /*
2 * This file is part of UBIFS.
4 * Copyright (C) 2006-2008 Nokia Corporation.
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
19 * Authors: Artem Bityutskiy (Битюцкий Артём)
20 * Adrian Hunter
24 * This header contains various key-related definitions and helper function.
25 * UBIFS allows several key schemes, so we access key fields only via these
26 * helpers. At the moment only one key scheme is supported.
28 * Simple key scheme
29 * ~~~~~~~~~~~~~~~~~
31 * Keys are 64-bits long. First 32-bits are inode number (parent inode number
32 * in case of direntry key). Next 3 bits are node type. The last 29 bits are
33 * 4KiB offset in case of inode node, and direntry hash in case of a direntry
34 * node. We use "r5" hash borrowed from reiserfs.
37 #ifndef __UBIFS_KEY_H__
38 #define __UBIFS_KEY_H__
40 /**
41 * key_mask_hash - mask a valid hash value.
42 * @val: value to be masked
44 * We use hash values as offset in directories, so values %0 and %1 are
45 * reserved for "." and "..". %2 is reserved for "end of readdir" marker. This
46 * function makes sure the reserved values are not used.
48 static inline uint32_t key_mask_hash(uint32_t hash)
50 hash &= UBIFS_S_KEY_HASH_MASK;
51 if (unlikely(hash <= 2))
52 hash += 3;
53 return hash;
56 /**
57 * key_r5_hash - R5 hash function (borrowed from reiserfs).
58 * @s: direntry name
59 * @len: name length
61 static inline uint32_t key_r5_hash(const char *s, int len)
63 uint32_t a = 0;
64 const signed char *str = (const signed char *)s;
66 while (*str) {
67 a += *str << 4;
68 a += *str >> 4;
69 a *= 11;
70 str++;
73 return key_mask_hash(a);
76 /**
77 * key_test_hash - testing hash function.
78 * @str: direntry name
79 * @len: name length
81 static inline uint32_t key_test_hash(const char *str, int len)
83 uint32_t a = 0;
85 len = min_t(uint32_t, len, 4);
86 memcpy(&a, str, len);
87 return key_mask_hash(a);
90 /**
91 * ino_key_init - initialize inode key.
92 * @c: UBIFS file-system description object
93 * @key: key to initialize
94 * @inum: inode number
96 static inline void ino_key_init(const struct ubifs_info *c,
97 union ubifs_key *key, ino_t inum)
99 key->u32[0] = inum;
100 key->u32[1] = UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS;
104 * ino_key_init_flash - initialize on-flash inode key.
105 * @c: UBIFS file-system description object
106 * @k: key to initialize
107 * @inum: inode number
109 static inline void ino_key_init_flash(const struct ubifs_info *c, void *k,
110 ino_t inum)
112 union ubifs_key *key = k;
114 key->j32[0] = cpu_to_le32(inum);
115 key->j32[1] = cpu_to_le32(UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS);
116 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
120 * lowest_ino_key - get the lowest possible inode key.
121 * @c: UBIFS file-system description object
122 * @key: key to initialize
123 * @inum: inode number
125 static inline void lowest_ino_key(const struct ubifs_info *c,
126 union ubifs_key *key, ino_t inum)
128 key->u32[0] = inum;
129 key->u32[1] = 0;
133 * highest_ino_key - get the highest possible inode key.
134 * @c: UBIFS file-system description object
135 * @key: key to initialize
136 * @inum: inode number
138 static inline void highest_ino_key(const struct ubifs_info *c,
139 union ubifs_key *key, ino_t inum)
141 key->u32[0] = inum;
142 key->u32[1] = 0xffffffff;
146 * dent_key_init - initialize directory entry key.
147 * @c: UBIFS file-system description object
148 * @key: key to initialize
149 * @inum: parent inode number
150 * @nm: direntry name and length
152 static inline void dent_key_init(const struct ubifs_info *c,
153 union ubifs_key *key, ino_t inum,
154 const struct qstr *nm)
156 uint32_t hash = c->key_hash(nm->name, nm->len);
158 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
159 key->u32[0] = inum;
160 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
164 * dent_key_init_hash - initialize directory entry key without re-calculating
165 * hash function.
166 * @c: UBIFS file-system description object
167 * @key: key to initialize
168 * @inum: parent inode number
169 * @hash: direntry name hash
171 static inline void dent_key_init_hash(const struct ubifs_info *c,
172 union ubifs_key *key, ino_t inum,
173 uint32_t hash)
175 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
176 key->u32[0] = inum;
177 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
181 * dent_key_init_flash - initialize on-flash directory entry key.
182 * @c: UBIFS file-system description object
183 * @k: key to initialize
184 * @inum: parent inode number
185 * @nm: direntry name and length
187 static inline void dent_key_init_flash(const struct ubifs_info *c, void *k,
188 ino_t inum, const struct qstr *nm)
190 union ubifs_key *key = k;
191 uint32_t hash = c->key_hash(nm->name, nm->len);
193 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
194 key->j32[0] = cpu_to_le32(inum);
195 key->j32[1] = cpu_to_le32(hash |
196 (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS));
197 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
201 * lowest_dent_key - get the lowest possible directory entry key.
202 * @c: UBIFS file-system description object
203 * @key: where to store the lowest key
204 * @inum: parent inode number
206 static inline void lowest_dent_key(const struct ubifs_info *c,
207 union ubifs_key *key, ino_t inum)
209 key->u32[0] = inum;
210 key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS;
214 * xent_key_init - initialize extended attribute entry key.
215 * @c: UBIFS file-system description object
216 * @key: key to initialize
217 * @inum: host inode number
218 * @nm: extended attribute entry name and length
220 static inline void xent_key_init(const struct ubifs_info *c,
221 union ubifs_key *key, ino_t inum,
222 const struct qstr *nm)
224 uint32_t hash = c->key_hash(nm->name, nm->len);
226 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
227 key->u32[0] = inum;
228 key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);
232 * xent_key_init_flash - initialize on-flash extended attribute entry key.
233 * @c: UBIFS file-system description object
234 * @k: key to initialize
235 * @inum: host inode number
236 * @nm: extended attribute entry name and length
238 static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,
239 ino_t inum, const struct qstr *nm)
241 union ubifs_key *key = k;
242 uint32_t hash = c->key_hash(nm->name, nm->len);
244 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
245 key->j32[0] = cpu_to_le32(inum);
246 key->j32[1] = cpu_to_le32(hash |
247 (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS));
248 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
252 * lowest_xent_key - get the lowest possible extended attribute entry key.
253 * @c: UBIFS file-system description object
254 * @key: where to store the lowest key
255 * @inum: host inode number
257 static inline void lowest_xent_key(const struct ubifs_info *c,
258 union ubifs_key *key, ino_t inum)
260 key->u32[0] = inum;
261 key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS;
265 * data_key_init - initialize data key.
266 * @c: UBIFS file-system description object
267 * @key: key to initialize
268 * @inum: inode number
269 * @block: block number
271 static inline void data_key_init(const struct ubifs_info *c,
272 union ubifs_key *key, ino_t inum,
273 unsigned int block)
275 ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK));
276 key->u32[0] = inum;
277 key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS);
281 * highest_data_key - get the highest possible data key for an inode.
282 * @c: UBIFS file-system description object
283 * @key: key to initialize
284 * @inum: inode number
286 static inline void highest_data_key(const struct ubifs_info *c,
287 union ubifs_key *key, ino_t inum)
289 data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK);
293 * trun_key_init - initialize truncation node key.
294 * @c: UBIFS file-system description object
295 * @key: key to initialize
296 * @inum: inode number
298 * Note, UBIFS does not have truncation keys on the media and this function is
299 * only used for purposes of replay.
301 static inline void trun_key_init(const struct ubifs_info *c,
302 union ubifs_key *key, ino_t inum)
304 key->u32[0] = inum;
305 key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS;
309 * key_type - get key type.
310 * @c: UBIFS file-system description object
311 * @key: key to get type of
313 static inline int key_type(const struct ubifs_info *c,
314 const union ubifs_key *key)
316 return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS;
320 * key_type_flash - get type of a on-flash formatted key.
321 * @c: UBIFS file-system description object
322 * @k: key to get type of
324 static inline int key_type_flash(const struct ubifs_info *c, const void *k)
326 const union ubifs_key *key = k;
328 return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
332 * key_inum - fetch inode number from key.
333 * @c: UBIFS file-system description object
334 * @k: key to fetch inode number from
336 static inline ino_t key_inum(const struct ubifs_info *c, const void *k)
338 const union ubifs_key *key = k;
340 return key->u32[0];
344 * key_inum_flash - fetch inode number from an on-flash formatted key.
345 * @c: UBIFS file-system description object
346 * @k: key to fetch inode number from
348 static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k)
350 const union ubifs_key *key = k;
352 return le32_to_cpu(key->j32[0]);
356 * key_hash - get directory entry hash.
357 * @c: UBIFS file-system description object
358 * @key: the key to get hash from
360 static inline uint32_t key_hash(const struct ubifs_info *c,
361 const union ubifs_key *key)
363 return key->u32[1] & UBIFS_S_KEY_HASH_MASK;
367 * key_hash_flash - get directory entry hash from an on-flash formatted key.
368 * @c: UBIFS file-system description object
369 * @k: the key to get hash from
371 static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k)
373 const union ubifs_key *key = k;
375 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK;
379 * key_block - get data block number.
380 * @c: UBIFS file-system description object
381 * @key: the key to get the block number from
383 static inline unsigned int key_block(const struct ubifs_info *c,
384 const union ubifs_key *key)
386 return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK;
390 * key_block_flash - get data block number from an on-flash formatted key.
391 * @c: UBIFS file-system description object
392 * @k: the key to get the block number from
394 static inline unsigned int key_block_flash(const struct ubifs_info *c,
395 const void *k)
397 const union ubifs_key *key = k;
399 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK;
403 * key_read - transform a key to in-memory format.
404 * @c: UBIFS file-system description object
405 * @from: the key to transform
406 * @to: the key to store the result
408 static inline void key_read(const struct ubifs_info *c, const void *from,
409 union ubifs_key *to)
411 const union ubifs_key *f = from;
413 to->u32[0] = le32_to_cpu(f->j32[0]);
414 to->u32[1] = le32_to_cpu(f->j32[1]);
418 * key_write - transform a key from in-memory format.
419 * @c: UBIFS file-system description object
420 * @from: the key to transform
421 * @to: the key to store the result
423 static inline void key_write(const struct ubifs_info *c,
424 const union ubifs_key *from, void *to)
426 union ubifs_key *t = to;
428 t->j32[0] = cpu_to_le32(from->u32[0]);
429 t->j32[1] = cpu_to_le32(from->u32[1]);
430 memset(to + 8, 0, UBIFS_MAX_KEY_LEN - 8);
434 * key_write_idx - transform a key from in-memory format for the index.
435 * @c: UBIFS file-system description object
436 * @from: the key to transform
437 * @to: the key to store the result
439 static inline void key_write_idx(const struct ubifs_info *c,
440 const union ubifs_key *from, void *to)
442 union ubifs_key *t = to;
444 t->j32[0] = cpu_to_le32(from->u32[0]);
445 t->j32[1] = cpu_to_le32(from->u32[1]);
449 * key_copy - copy a key.
450 * @c: UBIFS file-system description object
451 * @from: the key to copy from
452 * @to: the key to copy to
454 static inline void key_copy(const struct ubifs_info *c,
455 const union ubifs_key *from, union ubifs_key *to)
457 to->u64[0] = from->u64[0];
461 * keys_cmp - compare keys.
462 * @c: UBIFS file-system description object
463 * @key1: the first key to compare
464 * @key2: the second key to compare
466 * This function compares 2 keys and returns %-1 if @key1 is less than
467 * @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2.
469 static inline int keys_cmp(const struct ubifs_info *c,
470 const union ubifs_key *key1,
471 const union ubifs_key *key2)
473 if (key1->u32[0] < key2->u32[0])
474 return -1;
475 if (key1->u32[0] > key2->u32[0])
476 return 1;
477 if (key1->u32[1] < key2->u32[1])
478 return -1;
479 if (key1->u32[1] > key2->u32[1])
480 return 1;
482 return 0;
486 * keys_eq - determine if keys are equivalent.
487 * @c: UBIFS file-system description object
488 * @key1: the first key to compare
489 * @key2: the second key to compare
491 * This function compares 2 keys and returns %1 if @key1 is equal to @key2 and
492 * %0 if not.
494 static inline int keys_eq(const struct ubifs_info *c,
495 const union ubifs_key *key1,
496 const union ubifs_key *key2)
498 if (key1->u32[0] != key2->u32[0])
499 return 0;
500 if (key1->u32[1] != key2->u32[1])
501 return 0;
502 return 1;
506 * is_hash_key - is a key vulnerable to hash collisions.
507 * @c: UBIFS file-system description object
508 * @key: key
510 * This function returns %1 if @key is a hashed key or %0 otherwise.
512 static inline int is_hash_key(const struct ubifs_info *c,
513 const union ubifs_key *key)
515 int type = key_type(c, key);
517 return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY;
521 * key_max_inode_size - get maximum file size allowed by current key format.
522 * @c: UBIFS file-system description object
524 static inline unsigned long long key_max_inode_size(const struct ubifs_info *c)
526 switch (c->key_fmt) {
527 case UBIFS_SIMPLE_KEY_FMT:
528 return (1ULL << UBIFS_S_KEY_BLOCK_BITS) * UBIFS_BLOCK_SIZE;
529 default:
530 return 0;
534 #endif /* !__UBIFS_KEY_H__ */