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Artem Bityutskiy1e517642008-07-14 19:08:37 +03001/*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 *
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.
9 *
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.
14 *
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
18 *
19 * Authors: Artem Bityutskiy (Битюцкий Артём)
20 * Adrian Hunter
21 */
22
23/*
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.
27 *
28 * Simple key scheme
29 * ~~~~~~~~~~~~~~~~~
30 *
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.
35 */
36
37#ifndef __UBIFS_KEY_H__
38#define __UBIFS_KEY_H__
39
40/**
Kukkonen Mika5dd7cbc2008-12-02 11:32:49 +020041 * key_mask_hash - mask a valid hash value.
42 * @val: value to be masked
43 *
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.
47 */
48static inline uint32_t key_mask_hash(uint32_t hash)
49{
50 hash &= UBIFS_S_KEY_HASH_MASK;
51 if (unlikely(hash <= 2))
52 hash += 3;
53 return hash;
54}
55
56/**
Artem Bityutskiy1e517642008-07-14 19:08:37 +030057 * key_r5_hash - R5 hash function (borrowed from reiserfs).
58 * @s: direntry name
59 * @len: name length
60 */
61static inline uint32_t key_r5_hash(const char *s, int len)
62{
63 uint32_t a = 0;
64 const signed char *str = (const signed char *)s;
65
66 while (*str) {
67 a += *str << 4;
68 a += *str >> 4;
69 a *= 11;
70 str++;
71 }
72
Kukkonen Mika5dd7cbc2008-12-02 11:32:49 +020073 return key_mask_hash(a);
Artem Bityutskiy1e517642008-07-14 19:08:37 +030074}
75
76/**
77 * key_test_hash - testing hash function.
78 * @str: direntry name
79 * @len: name length
80 */
81static inline uint32_t key_test_hash(const char *str, int len)
82{
83 uint32_t a = 0;
84
85 len = min_t(uint32_t, len, 4);
86 memcpy(&a, str, len);
Kukkonen Mika5dd7cbc2008-12-02 11:32:49 +020087 return key_mask_hash(a);
Artem Bityutskiy1e517642008-07-14 19:08:37 +030088}
89
90/**
91 * ino_key_init - initialize inode key.
92 * @c: UBIFS file-system description object
93 * @key: key to initialize
94 * @inum: inode number
95 */
96static inline void ino_key_init(const struct ubifs_info *c,
97 union ubifs_key *key, ino_t inum)
98{
99 key->u32[0] = inum;
100 key->u32[1] = UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS;
101}
102
103/**
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
108 */
109static inline void ino_key_init_flash(const struct ubifs_info *c, void *k,
110 ino_t inum)
111{
112 union ubifs_key *key = k;
113
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);
117}
118
119/**
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
124 */
125static inline void lowest_ino_key(const struct ubifs_info *c,
126 union ubifs_key *key, ino_t inum)
127{
128 key->u32[0] = inum;
129 key->u32[1] = 0;
130}
131
132/**
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
137 */
138static inline void highest_ino_key(const struct ubifs_info *c,
139 union ubifs_key *key, ino_t inum)
140{
141 key->u32[0] = inum;
142 key->u32[1] = 0xffffffff;
143}
144
145/**
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
151 */
152static inline void dent_key_init(const struct ubifs_info *c,
153 union ubifs_key *key, ino_t inum,
154 const struct qstr *nm)
155{
156 uint32_t hash = c->key_hash(nm->name, nm->len);
157
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);
161}
162
163/**
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
170 */
171static inline void dent_key_init_hash(const struct ubifs_info *c,
172 union ubifs_key *key, ino_t inum,
173 uint32_t hash)
174{
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);
178}
179
180/**
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
186 */
187static inline void dent_key_init_flash(const struct ubifs_info *c, void *k,
188 ino_t inum, const struct qstr *nm)
189{
190 union ubifs_key *key = k;
191 uint32_t hash = c->key_hash(nm->name, nm->len);
192
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);
198}
199
200/**
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
205 */
206static inline void lowest_dent_key(const struct ubifs_info *c,
207 union ubifs_key *key, ino_t inum)
208{
209 key->u32[0] = inum;
210 key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS;
211}
212
213/**
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
219 */
220static inline void xent_key_init(const struct ubifs_info *c,
221 union ubifs_key *key, ino_t inum,
222 const struct qstr *nm)
223{
224 uint32_t hash = c->key_hash(nm->name, nm->len);
225
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);
229}
230
231/**
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300232 * 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
237 */
238static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,
239 ino_t inum, const struct qstr *nm)
240{
241 union ubifs_key *key = k;
242 uint32_t hash = c->key_hash(nm->name, nm->len);
243
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);
249}
250
251/**
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
256 */
257static inline void lowest_xent_key(const struct ubifs_info *c,
258 union ubifs_key *key, ino_t inum)
259{
260 key->u32[0] = inum;
261 key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS;
262}
263
264/**
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
270 */
271static inline void data_key_init(const struct ubifs_info *c,
272 union ubifs_key *key, ino_t inum,
273 unsigned int block)
274{
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);
278}
279
280/**
Artem Bityutskiye3c3efc2009-08-27 16:34:19 +0300281 * 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
285 */
286static inline void highest_data_key(const struct ubifs_info *c,
287 union ubifs_key *key, ino_t inum)
288{
289 data_key_init(c, key, inum, UBIFS_S_KEY_BLOCK_MASK);
290}
291
292/**
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300293 * trun_key_init - initialize truncation node key.
294 * @c: UBIFS file-system description object
295 * @key: key to initialize
296 * @inum: inode number
297 *
298 * Note, UBIFS does not have truncation keys on the media and this function is
299 * only used for purposes of replay.
300 */
301static inline void trun_key_init(const struct ubifs_info *c,
302 union ubifs_key *key, ino_t inum)
303{
304 key->u32[0] = inum;
305 key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS;
306}
307
308/**
309 * key_type - get key type.
310 * @c: UBIFS file-system description object
311 * @key: key to get type of
312 */
313static inline int key_type(const struct ubifs_info *c,
314 const union ubifs_key *key)
315{
316 return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS;
317}
318
319/**
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
323 */
324static inline int key_type_flash(const struct ubifs_info *c, const void *k)
325{
326 const union ubifs_key *key = k;
327
Harvey Harrison0ecb9522008-10-24 10:52:57 -0700328 return le32_to_cpu(key->j32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300329}
330
331/**
332 * key_inum - fetch inode number from key.
333 * @c: UBIFS file-system description object
334 * @k: key to fetch inode number from
335 */
336static inline ino_t key_inum(const struct ubifs_info *c, const void *k)
337{
338 const union ubifs_key *key = k;
339
340 return key->u32[0];
341}
342
343/**
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
347 */
348static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k)
349{
350 const union ubifs_key *key = k;
351
352 return le32_to_cpu(key->j32[0]);
353}
354
355/**
356 * key_hash - get directory entry hash.
357 * @c: UBIFS file-system description object
358 * @key: the key to get hash from
359 */
Artem Bityutskiycb4f9522009-03-07 20:53:41 +0200360static inline uint32_t key_hash(const struct ubifs_info *c,
361 const union ubifs_key *key)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300362{
363 return key->u32[1] & UBIFS_S_KEY_HASH_MASK;
364}
365
366/**
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
370 */
Artem Bityutskiycb4f9522009-03-07 20:53:41 +0200371static inline uint32_t key_hash_flash(const struct ubifs_info *c, const void *k)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300372{
373 const union ubifs_key *key = k;
374
375 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK;
376}
377
378/**
379 * key_block - get data block number.
380 * @c: UBIFS file-system description object
381 * @key: the key to get the block number from
382 */
383static inline unsigned int key_block(const struct ubifs_info *c,
384 const union ubifs_key *key)
385{
386 return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK;
387}
388
389/**
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
393 */
394static inline unsigned int key_block_flash(const struct ubifs_info *c,
395 const void *k)
396{
397 const union ubifs_key *key = k;
398
Harvey Harrison0ecb9522008-10-24 10:52:57 -0700399 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_BLOCK_MASK;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300400}
401
402/**
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
407 */
408static inline void key_read(const struct ubifs_info *c, const void *from,
409 union ubifs_key *to)
410{
411 const union ubifs_key *f = from;
412
413 to->u32[0] = le32_to_cpu(f->j32[0]);
414 to->u32[1] = le32_to_cpu(f->j32[1]);
415}
416
417/**
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
422 */
423static inline void key_write(const struct ubifs_info *c,
424 const union ubifs_key *from, void *to)
425{
426 union ubifs_key *t = to;
427
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);
431}
432
433/**
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
438 */
439static inline void key_write_idx(const struct ubifs_info *c,
440 const union ubifs_key *from, void *to)
441{
442 union ubifs_key *t = to;
443
444 t->j32[0] = cpu_to_le32(from->u32[0]);
445 t->j32[1] = cpu_to_le32(from->u32[1]);
446}
447
448/**
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
453 */
454static inline void key_copy(const struct ubifs_info *c,
455 const union ubifs_key *from, union ubifs_key *to)
456{
457 to->u64[0] = from->u64[0];
458}
459
460/**
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
465 *
466 * This function compares 2 keys and returns %-1 if @key1 is less than
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300467 * @key2, %0 if the keys are equivalent and %1 if @key1 is greater than @key2.
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300468 */
469static inline int keys_cmp(const struct ubifs_info *c,
470 const union ubifs_key *key1,
471 const union ubifs_key *key2)
472{
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;
481
482 return 0;
483}
484
485/**
Adrian Hunter4793e7c2008-09-02 16:29:46 +0300486 * 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
490 *
491 * This function compares 2 keys and returns %1 if @key1 is equal to @key2 and
492 * %0 if not.
493 */
494static inline int keys_eq(const struct ubifs_info *c,
495 const union ubifs_key *key1,
496 const union ubifs_key *key2)
497{
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;
503}
504
505/**
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300506 * is_hash_key - is a key vulnerable to hash collisions.
507 * @c: UBIFS file-system description object
508 * @key: key
509 *
510 * This function returns %1 if @key is a hashed key or %0 otherwise.
511 */
512static inline int is_hash_key(const struct ubifs_info *c,
513 const union ubifs_key *key)
514{
515 int type = key_type(c, key);
516
517 return type == UBIFS_DENT_KEY || type == UBIFS_XENT_KEY;
518}
519
520/**
521 * key_max_inode_size - get maximum file size allowed by current key format.
522 * @c: UBIFS file-system description object
523 */
524static inline unsigned long long key_max_inode_size(const struct ubifs_info *c)
525{
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;
531 }
532}
Artem Bityutskiye3c3efc2009-08-27 16:34:19 +0300533
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300534#endif /* !__UBIFS_KEY_H__ */