Artem Bityutskiy | 1e51764 | 2008-07-14 19:08:37 +0300 | [diff] [blame] | 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 | */ |
| 45 | static 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 | */ |
| 74 | static 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 | */ |
| 92 | static 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 | */ |
| 105 | static 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 | */ |
| 121 | static 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 | */ |
| 134 | static 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 | */ |
| 148 | static 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 | */ |
| 167 | static 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 | */ |
| 183 | static 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 | */ |
| 202 | static 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 | */ |
| 216 | static 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 | */ |
| 235 | static 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 | */ |
| 251 | static 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 | */ |
| 270 | static 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 | */ |
| 284 | static 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 | */ |
| 300 | static 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 | */ |
| 321 | static 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 | */ |
| 333 | static 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 | */ |
| 344 | static 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 | */ |
| 356 | static 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 | */ |
| 368 | static 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 | */ |
| 380 | static 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 | */ |
| 391 | static 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 | */ |
| 403 | static 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 | */ |
| 414 | static 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 | */ |
| 428 | static 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 | */ |
| 443 | static 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 | */ |
| 459 | static 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 | */ |
| 474 | static 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 | */ |
| 489 | static 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 | */ |
| 512 | static 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 | */ |
| 524 | static 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__ */ |