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authorArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2008-07-14 12:08:37 -0400
committerArtem Bityutskiy <Artem.Bityutskiy@nokia.com>2008-07-15 10:35:15 -0400
commit1e51764a3c2ac05a23a22b2a95ddee4d9bffb16d (patch)
tree919debdd48aef9eee9ff0e8f465ef2649325b993 /fs/ubifs/key.h
parente56a99d5a42dcb91e622ae7a0289d8fb2ddabffb (diff)
UBIFS: add new flash file system
This is a new flash file system. See http://www.linux-mtd.infradead.org/doc/ubifs.html Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com> Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Diffstat (limited to 'fs/ubifs/key.h')
-rw-r--r--fs/ubifs/key.h533
1 files changed, 533 insertions, 0 deletions
diff --git a/fs/ubifs/key.h b/fs/ubifs/key.h
new file mode 100644
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+++ b/fs/ubifs/key.h
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1/*
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/**
41 * key_r5_hash - R5 hash function (borrowed from reiserfs).
42 * @s: direntry name
43 * @len: name length
44 */
45static inline uint32_t key_r5_hash(const char *s, int len)
46{
47 uint32_t a = 0;
48 const signed char *str = (const signed char *)s;
49
50 while (*str) {
51 a += *str << 4;
52 a += *str >> 4;
53 a *= 11;
54 str++;
55 }
56
57 a &= UBIFS_S_KEY_HASH_MASK;
58
59 /*
60 * We use hash values as offset in directories, so values %0 and %1 are
61 * reserved for "." and "..". %2 is reserved for "end of readdir"
62 * marker.
63 */
64 if (unlikely(a >= 0 && a <= 2))
65 a += 3;
66 return a;
67}
68
69/**
70 * key_test_hash - testing hash function.
71 * @str: direntry name
72 * @len: name length
73 */
74static inline uint32_t key_test_hash(const char *str, int len)
75{
76 uint32_t a = 0;
77
78 len = min_t(uint32_t, len, 4);
79 memcpy(&a, str, len);
80 a &= UBIFS_S_KEY_HASH_MASK;
81 if (unlikely(a >= 0 && a <= 2))
82 a += 3;
83 return a;
84}
85
86/**
87 * ino_key_init - initialize inode key.
88 * @c: UBIFS file-system description object
89 * @key: key to initialize
90 * @inum: inode number
91 */
92static inline void ino_key_init(const struct ubifs_info *c,
93 union ubifs_key *key, ino_t inum)
94{
95 key->u32[0] = inum;
96 key->u32[1] = UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS;
97}
98
99/**
100 * ino_key_init_flash - initialize on-flash inode key.
101 * @c: UBIFS file-system description object
102 * @k: key to initialize
103 * @inum: inode number
104 */
105static inline void ino_key_init_flash(const struct ubifs_info *c, void *k,
106 ino_t inum)
107{
108 union ubifs_key *key = k;
109
110 key->j32[0] = cpu_to_le32(inum);
111 key->j32[1] = cpu_to_le32(UBIFS_INO_KEY << UBIFS_S_KEY_BLOCK_BITS);
112 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
113}
114
115/**
116 * lowest_ino_key - get the lowest possible inode key.
117 * @c: UBIFS file-system description object
118 * @key: key to initialize
119 * @inum: inode number
120 */
121static inline void lowest_ino_key(const struct ubifs_info *c,
122 union ubifs_key *key, ino_t inum)
123{
124 key->u32[0] = inum;
125 key->u32[1] = 0;
126}
127
128/**
129 * highest_ino_key - get the highest possible inode key.
130 * @c: UBIFS file-system description object
131 * @key: key to initialize
132 * @inum: inode number
133 */
134static inline void highest_ino_key(const struct ubifs_info *c,
135 union ubifs_key *key, ino_t inum)
136{
137 key->u32[0] = inum;
138 key->u32[1] = 0xffffffff;
139}
140
141/**
142 * dent_key_init - initialize directory entry key.
143 * @c: UBIFS file-system description object
144 * @key: key to initialize
145 * @inum: parent inode number
146 * @nm: direntry name and length
147 */
148static inline void dent_key_init(const struct ubifs_info *c,
149 union ubifs_key *key, ino_t inum,
150 const struct qstr *nm)
151{
152 uint32_t hash = c->key_hash(nm->name, nm->len);
153
154 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
155 key->u32[0] = inum;
156 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
157}
158
159/**
160 * dent_key_init_hash - initialize directory entry key without re-calculating
161 * hash function.
162 * @c: UBIFS file-system description object
163 * @key: key to initialize
164 * @inum: parent inode number
165 * @hash: direntry name hash
166 */
167static inline void dent_key_init_hash(const struct ubifs_info *c,
168 union ubifs_key *key, ino_t inum,
169 uint32_t hash)
170{
171 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
172 key->u32[0] = inum;
173 key->u32[1] = hash | (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS);
174}
175
176/**
177 * dent_key_init_flash - initialize on-flash directory entry key.
178 * @c: UBIFS file-system description object
179 * @k: key to initialize
180 * @inum: parent inode number
181 * @nm: direntry name and length
182 */
183static inline void dent_key_init_flash(const struct ubifs_info *c, void *k,
184 ino_t inum, const struct qstr *nm)
185{
186 union ubifs_key *key = k;
187 uint32_t hash = c->key_hash(nm->name, nm->len);
188
189 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
190 key->j32[0] = cpu_to_le32(inum);
191 key->j32[1] = cpu_to_le32(hash |
192 (UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS));
193 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
194}
195
196/**
197 * lowest_dent_key - get the lowest possible directory entry key.
198 * @c: UBIFS file-system description object
199 * @key: where to store the lowest key
200 * @inum: parent inode number
201 */
202static inline void lowest_dent_key(const struct ubifs_info *c,
203 union ubifs_key *key, ino_t inum)
204{
205 key->u32[0] = inum;
206 key->u32[1] = UBIFS_DENT_KEY << UBIFS_S_KEY_HASH_BITS;
207}
208
209/**
210 * xent_key_init - initialize extended attribute entry key.
211 * @c: UBIFS file-system description object
212 * @key: key to initialize
213 * @inum: host inode number
214 * @nm: extended attribute entry name and length
215 */
216static inline void xent_key_init(const struct ubifs_info *c,
217 union ubifs_key *key, ino_t inum,
218 const struct qstr *nm)
219{
220 uint32_t hash = c->key_hash(nm->name, nm->len);
221
222 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
223 key->u32[0] = inum;
224 key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);
225}
226
227/**
228 * xent_key_init_hash - initialize extended attribute entry key without
229 * re-calculating hash function.
230 * @c: UBIFS file-system description object
231 * @key: key to initialize
232 * @inum: host inode number
233 * @hash: extended attribute entry name hash
234 */
235static inline void xent_key_init_hash(const struct ubifs_info *c,
236 union ubifs_key *key, ino_t inum,
237 uint32_t hash)
238{
239 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
240 key->u32[0] = inum;
241 key->u32[1] = hash | (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS);
242}
243
244/**
245 * xent_key_init_flash - initialize on-flash extended attribute entry key.
246 * @c: UBIFS file-system description object
247 * @k: key to initialize
248 * @inum: host inode number
249 * @nm: extended attribute entry name and length
250 */
251static inline void xent_key_init_flash(const struct ubifs_info *c, void *k,
252 ino_t inum, const struct qstr *nm)
253{
254 union ubifs_key *key = k;
255 uint32_t hash = c->key_hash(nm->name, nm->len);
256
257 ubifs_assert(!(hash & ~UBIFS_S_KEY_HASH_MASK));
258 key->j32[0] = cpu_to_le32(inum);
259 key->j32[1] = cpu_to_le32(hash |
260 (UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS));
261 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
262}
263
264/**
265 * lowest_xent_key - get the lowest possible extended attribute entry key.
266 * @c: UBIFS file-system description object
267 * @key: where to store the lowest key
268 * @inum: host inode number
269 */
270static inline void lowest_xent_key(const struct ubifs_info *c,
271 union ubifs_key *key, ino_t inum)
272{
273 key->u32[0] = inum;
274 key->u32[1] = UBIFS_XENT_KEY << UBIFS_S_KEY_HASH_BITS;
275}
276
277/**
278 * data_key_init - initialize data key.
279 * @c: UBIFS file-system description object
280 * @key: key to initialize
281 * @inum: inode number
282 * @block: block number
283 */
284static inline void data_key_init(const struct ubifs_info *c,
285 union ubifs_key *key, ino_t inum,
286 unsigned int block)
287{
288 ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK));
289 key->u32[0] = inum;
290 key->u32[1] = block | (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS);
291}
292
293/**
294 * data_key_init_flash - initialize on-flash data key.
295 * @c: UBIFS file-system description object
296 * @k: key to initialize
297 * @inum: inode number
298 * @block: block number
299 */
300static inline void data_key_init_flash(const struct ubifs_info *c, void *k,
301 ino_t inum, unsigned int block)
302{
303 union ubifs_key *key = k;
304
305 ubifs_assert(!(block & ~UBIFS_S_KEY_BLOCK_MASK));
306 key->j32[0] = cpu_to_le32(inum);
307 key->j32[1] = cpu_to_le32(block |
308 (UBIFS_DATA_KEY << UBIFS_S_KEY_BLOCK_BITS));
309 memset(k + 8, 0, UBIFS_MAX_KEY_LEN - 8);
310}
311
312/**
313 * trun_key_init - initialize truncation node key.
314 * @c: UBIFS file-system description object
315 * @key: key to initialize
316 * @inum: inode number
317 *
318 * Note, UBIFS does not have truncation keys on the media and this function is
319 * only used for purposes of replay.
320 */
321static inline void trun_key_init(const struct ubifs_info *c,
322 union ubifs_key *key, ino_t inum)
323{
324 key->u32[0] = inum;
325 key->u32[1] = UBIFS_TRUN_KEY << UBIFS_S_KEY_BLOCK_BITS;
326}
327
328/**
329 * key_type - get key type.
330 * @c: UBIFS file-system description object
331 * @key: key to get type of
332 */
333static inline int key_type(const struct ubifs_info *c,
334 const union ubifs_key *key)
335{
336 return key->u32[1] >> UBIFS_S_KEY_BLOCK_BITS;
337}
338
339/**
340 * key_type_flash - get type of a on-flash formatted key.
341 * @c: UBIFS file-system description object
342 * @k: key to get type of
343 */
344static inline int key_type_flash(const struct ubifs_info *c, const void *k)
345{
346 const union ubifs_key *key = k;
347
348 return le32_to_cpu(key->u32[1]) >> UBIFS_S_KEY_BLOCK_BITS;
349}
350
351/**
352 * key_inum - fetch inode number from key.
353 * @c: UBIFS file-system description object
354 * @k: key to fetch inode number from
355 */
356static inline ino_t key_inum(const struct ubifs_info *c, const void *k)
357{
358 const union ubifs_key *key = k;
359
360 return key->u32[0];
361}
362
363/**
364 * key_inum_flash - fetch inode number from an on-flash formatted key.
365 * @c: UBIFS file-system description object
366 * @k: key to fetch inode number from
367 */
368static inline ino_t key_inum_flash(const struct ubifs_info *c, const void *k)
369{
370 const union ubifs_key *key = k;
371
372 return le32_to_cpu(key->j32[0]);
373}
374
375/**
376 * key_hash - get directory entry hash.
377 * @c: UBIFS file-system description object
378 * @key: the key to get hash from
379 */
380static inline int key_hash(const struct ubifs_info *c,
381 const union ubifs_key *key)
382{
383 return key->u32[1] & UBIFS_S_KEY_HASH_MASK;
384}
385
386/**
387 * key_hash_flash - get directory entry hash from an on-flash formatted key.
388 * @c: UBIFS file-system description object
389 * @k: the key to get hash from
390 */
391static inline int key_hash_flash(const struct ubifs_info *c, const void *k)
392{
393 const union ubifs_key *key = k;
394
395 return le32_to_cpu(key->j32[1]) & UBIFS_S_KEY_HASH_MASK;
396}
397
398/**
399 * key_block - get data block number.
400 * @c: UBIFS file-system description object
401 * @key: the key to get the block number from
402 */
403static inline unsigned int key_block(const struct ubifs_info *c,
404 const union ubifs_key *key)
405{
406 return key->u32[1] & UBIFS_S_KEY_BLOCK_MASK;
407}
408
409/**
410 * key_block_flash - get data block number from an on-flash formatted key.
411 * @c: UBIFS file-system description object
412 * @k: the key to get the block number from
413 */
414static inline unsigned int key_block_flash(const struct ubifs_info *c,
415 const void *k)
416{
417 const union ubifs_key *key = k;
418
419 return le32_to_cpu(key->u32[1]) & UBIFS_S_KEY_BLOCK_MASK;
420}
421
422/**
423 * key_read - transform a key to in-memory format.
424 * @c: UBIFS file-system description object
425 * @from: the key to transform
426 * @to: the key to store the result
427 */
428static inline void key_read(const struct ubifs_info *c, const void *from,
429 union ubifs_key *to)
430{
431 const union ubifs_key *f = from;
432
433 to->u32[0] = le32_to_cpu(f->j32[0]);
434 to->u32[1] = le32_to_cpu(f->j32[1]);
435}
436
437/**
438 * key_write - transform a key from in-memory format.
439 * @c: UBIFS file-system description object
440 * @from: the key to transform
441 * @to: the key to store the result
442 */
443static inline void key_write(const struct ubifs_info *c,
444 const union ubifs_key *from, void *to)
445{
446 union ubifs_key *t = to;
447
448 t->j32[0] = cpu_to_le32(from->u32[0]);
449 t->j32[1] = cpu_to_le32(from->u32[1]);
450 memset(to + 8, 0, UBIFS_MAX_KEY_LEN - 8);
451}
452
453/**
454 * key_write_idx - transform a key from in-memory format for the index.
455 * @c: UBIFS file-system description object
456 * @from: the key to transform
457 * @to: the key to store the result
458 */
459static inline void key_write_idx(const struct ubifs_info *c,
460 const union ubifs_key *from, void *to)
461{
462 union ubifs_key *t = to;
463
464 t->j32[0] = cpu_to_le32(from->u32[0]);
465 t->j32[1] = cpu_to_le32(from->u32[1]);
466}
467
468/**
469 * key_copy - copy a key.
470 * @c: UBIFS file-system description object
471 * @from: the key to copy from
472 * @to: the key to copy to
473 */
474static inline void key_copy(const struct ubifs_info *c,
475 const union ubifs_key *from, union ubifs_key *to)
476{
477 to->u64[0] = from->u64[0];
478}
479
480/**
481 * keys_cmp - compare keys.
482 * @c: UBIFS file-system description object
483 * @key1: the first key to compare
484 * @key2: the second key to compare
485 *
486 * This function compares 2 keys and returns %-1 if @key1 is less than
487 * @key2, 0 if the keys are equivalent and %1 if @key1 is greater than @key2.
488 */
489static inline int keys_cmp(const struct ubifs_info *c,
490 const union ubifs_key *key1,
491 const union ubifs_key *key2)
492{
493 if (key1->u32[0] < key2->u32[0])
494 return -1;
495 if (key1->u32[0] > key2->u32[0])
496 return 1;
497 if (key1->u32[1] < key2->u32[1])
498 return -1;
499 if (key1->u32[1] > key2->u32[1])
500 return 1;
501
502 return 0;
503}
504
505/**
506 * 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}
533#endif /* !__UBIFS_KEY_H__ */