1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * This file is part of UBIFS. 4 * 5 * Copyright (C) 2006-2008 Nokia Corporation. 6 * 7 * Authors: Adrian Hunter 8 * Artem Bityutskiy (Битюцкий Артём) 9 */ 10 11 /* 12 * This file contains miscelanious TNC-related functions shared betweend 13 * different files. This file does not form any logically separate TNC 14 * sub-system. The file was created because there is a lot of TNC code and 15 * putting it all in one file would make that file too big and unreadable. 16 */ 17 18 #include "ubifs.h" 19 20 /** 21 * ubifs_tnc_levelorder_next - next TNC tree element in levelorder traversal. 22 * @c: UBIFS file-system description object 23 * @zr: root of the subtree to traverse 24 * @znode: previous znode 25 * 26 * This function implements levelorder TNC traversal. The LNC is ignored. 27 * Returns the next element or %NULL if @znode is already the last one. 28 */ 29 struct ubifs_znode *ubifs_tnc_levelorder_next(const struct ubifs_info *c, 30 struct ubifs_znode *zr, 31 struct ubifs_znode *znode) 32 { 33 int level, iip, level_search = 0; 34 struct ubifs_znode *zn; 35 36 ubifs_assert(c, zr); 37 38 if (unlikely(!znode)) 39 return zr; 40 41 if (unlikely(znode == zr)) { 42 if (znode->level == 0) 43 return NULL; 44 return ubifs_tnc_find_child(zr, 0); 45 } 46 47 level = znode->level; 48 49 iip = znode->iip; 50 while (1) { 51 ubifs_assert(c, znode->level <= zr->level); 52 53 /* 54 * First walk up until there is a znode with next branch to 55 * look at. 56 */ 57 while (znode->parent != zr && iip >= znode->parent->child_cnt) { 58 znode = znode->parent; 59 iip = znode->iip; 60 } 61 62 if (unlikely(znode->parent == zr && 63 iip >= znode->parent->child_cnt)) { 64 /* This level is done, switch to the lower one */ 65 level -= 1; 66 if (level_search || level < 0) 67 /* 68 * We were already looking for znode at lower 69 * level ('level_search'). As we are here 70 * again, it just does not exist. Or all levels 71 * were finished ('level < 0'). 72 */ 73 return NULL; 74 75 level_search = 1; 76 iip = -1; 77 znode = ubifs_tnc_find_child(zr, 0); 78 ubifs_assert(c, znode); 79 } 80 81 /* Switch to the next index */ 82 zn = ubifs_tnc_find_child(znode->parent, iip + 1); 83 if (!zn) { 84 /* No more children to look at, we have walk up */ 85 iip = znode->parent->child_cnt; 86 continue; 87 } 88 89 /* Walk back down to the level we came from ('level') */ 90 while (zn->level != level) { 91 znode = zn; 92 zn = ubifs_tnc_find_child(zn, 0); 93 if (!zn) { 94 /* 95 * This path is not too deep so it does not 96 * reach 'level'. Try next path. 97 */ 98 iip = znode->iip; 99 break; 100 } 101 } 102 103 if (zn) { 104 ubifs_assert(c, zn->level >= 0); 105 return zn; 106 } 107 } 108 } 109 110 /** 111 * ubifs_search_zbranch - search znode branch. 112 * @c: UBIFS file-system description object 113 * @znode: znode to search in 114 * @key: key to search for 115 * @n: znode branch slot number is returned here 116 * 117 * This is a helper function which search branch with key @key in @znode using 118 * binary search. The result of the search may be: 119 * o exact match, then %1 is returned, and the slot number of the branch is 120 * stored in @n; 121 * o no exact match, then %0 is returned and the slot number of the left 122 * closest branch is returned in @n; the slot if all keys in this znode are 123 * greater than @key, then %-1 is returned in @n. 124 */ 125 int ubifs_search_zbranch(const struct ubifs_info *c, 126 const struct ubifs_znode *znode, 127 const union ubifs_key *key, int *n) 128 { 129 int beg = 0, end = znode->child_cnt, mid; 130 int cmp; 131 const struct ubifs_zbranch *zbr = &znode->zbranch[0]; 132 133 ubifs_assert(c, end > beg); 134 135 while (end > beg) { 136 mid = (beg + end) >> 1; 137 cmp = keys_cmp(c, key, &zbr[mid].key); 138 if (cmp > 0) 139 beg = mid + 1; 140 else if (cmp < 0) 141 end = mid; 142 else { 143 *n = mid; 144 return 1; 145 } 146 } 147 148 *n = end - 1; 149 150 /* The insert point is after *n */ 151 ubifs_assert(c, *n >= -1 && *n < znode->child_cnt); 152 if (*n == -1) 153 ubifs_assert(c, keys_cmp(c, key, &zbr[0].key) < 0); 154 else 155 ubifs_assert(c, keys_cmp(c, key, &zbr[*n].key) > 0); 156 if (*n + 1 < znode->child_cnt) 157 ubifs_assert(c, keys_cmp(c, key, &zbr[*n + 1].key) < 0); 158 159 return 0; 160 } 161 162 /** 163 * ubifs_tnc_postorder_first - find first znode to do postorder tree traversal. 164 * @znode: znode to start at (root of the sub-tree to traverse) 165 * 166 * Find the lowest leftmost znode in a subtree of the TNC tree. The LNC is 167 * ignored. 168 */ 169 struct ubifs_znode *ubifs_tnc_postorder_first(struct ubifs_znode *znode) 170 { 171 if (unlikely(!znode)) 172 return NULL; 173 174 while (znode->level > 0) { 175 struct ubifs_znode *child; 176 177 child = ubifs_tnc_find_child(znode, 0); 178 if (!child) 179 return znode; 180 znode = child; 181 } 182 183 return znode; 184 } 185 186 /** 187 * ubifs_tnc_postorder_next - next TNC tree element in postorder traversal. 188 * @c: UBIFS file-system description object 189 * @znode: previous znode 190 * 191 * This function implements postorder TNC traversal. The LNC is ignored. 192 * Returns the next element or %NULL if @znode is already the last one. 193 */ 194 struct ubifs_znode *ubifs_tnc_postorder_next(const struct ubifs_info *c, 195 struct ubifs_znode *znode) 196 { 197 struct ubifs_znode *zn; 198 199 ubifs_assert(c, znode); 200 if (unlikely(!znode->parent)) 201 return NULL; 202 203 /* Switch to the next index in the parent */ 204 zn = ubifs_tnc_find_child(znode->parent, znode->iip + 1); 205 if (!zn) 206 /* This is in fact the last child, return parent */ 207 return znode->parent; 208 209 /* Go to the first znode in this new subtree */ 210 return ubifs_tnc_postorder_first(zn); 211 } 212 213 /** 214 * ubifs_destroy_tnc_subtree - destroy all znodes connected to a subtree. 215 * @c: UBIFS file-system description object 216 * @znode: znode defining subtree to destroy 217 * 218 * This function destroys subtree of the TNC tree. Returns number of clean 219 * znodes in the subtree. 220 */ 221 long ubifs_destroy_tnc_subtree(const struct ubifs_info *c, 222 struct ubifs_znode *znode) 223 { 224 struct ubifs_znode *zn = ubifs_tnc_postorder_first(znode); 225 long clean_freed = 0; 226 int n; 227 228 ubifs_assert(c, zn); 229 while (1) { 230 for (n = 0; n < zn->child_cnt; n++) { 231 if (!zn->zbranch[n].znode) 232 continue; 233 234 if (zn->level > 0 && 235 !ubifs_zn_dirty(zn->zbranch[n].znode)) 236 clean_freed += 1; 237 238 cond_resched(); 239 kfree(zn->zbranch[n].znode); 240 } 241 242 if (zn == znode) { 243 if (!ubifs_zn_dirty(zn)) 244 clean_freed += 1; 245 kfree(zn); 246 return clean_freed; 247 } 248 249 zn = ubifs_tnc_postorder_next(c, zn); 250 } 251 } 252 253 /** 254 * ubifs_destroy_tnc_tree - destroy all znodes connected to the TNC tree. 255 * @c: UBIFS file-system description object 256 * 257 * This function destroys the whole TNC tree and updates clean global znode 258 * count. 259 */ 260 void ubifs_destroy_tnc_tree(struct ubifs_info *c) 261 { 262 long n, freed; 263 264 if (!c->zroot.znode) 265 return; 266 267 n = atomic_long_read(&c->clean_zn_cnt); 268 freed = ubifs_destroy_tnc_subtree(c, c->zroot.znode); 269 ubifs_assert(c, freed == n); 270 atomic_long_sub(n, &ubifs_clean_zn_cnt); 271 272 c->zroot.znode = NULL; 273 } 274 275 /** 276 * read_znode - read an indexing node from flash and fill znode. 277 * @c: UBIFS file-system description object 278 * @zzbr: the zbranch describing the node to read 279 * @znode: znode to read to 280 * 281 * This function reads an indexing node from the flash media and fills znode 282 * with the read data. Returns zero in case of success and a negative error 283 * code in case of failure. The read indexing node is validated and if anything 284 * is wrong with it, this function prints complaint messages and returns 285 * %-EINVAL. 286 */ 287 static int read_znode(struct ubifs_info *c, struct ubifs_zbranch *zzbr, 288 struct ubifs_znode *znode) 289 { 290 int lnum = zzbr->lnum; 291 int offs = zzbr->offs; 292 int len = zzbr->len; 293 int i, err, type, cmp; 294 struct ubifs_idx_node *idx; 295 296 idx = kmalloc(c->max_idx_node_sz, GFP_NOFS); 297 if (!idx) 298 return -ENOMEM; 299 300 err = ubifs_read_node(c, idx, UBIFS_IDX_NODE, len, lnum, offs); 301 if (err < 0) { 302 kfree(idx); 303 return err; 304 } 305 306 err = ubifs_node_check_hash(c, idx, zzbr->hash); 307 if (err) { 308 ubifs_bad_hash(c, idx, zzbr->hash, lnum, offs); 309 kfree(idx); 310 return err; 311 } 312 313 znode->child_cnt = le16_to_cpu(idx->child_cnt); 314 znode->level = le16_to_cpu(idx->level); 315 316 dbg_tnc("LEB %d:%d, level %d, %d branch", 317 lnum, offs, znode->level, znode->child_cnt); 318 319 if (znode->child_cnt > c->fanout || znode->level > UBIFS_MAX_LEVELS) { 320 ubifs_err(c, "current fanout %d, branch count %d", 321 c->fanout, znode->child_cnt); 322 ubifs_err(c, "max levels %d, znode level %d", 323 UBIFS_MAX_LEVELS, znode->level); 324 goto out_dump; 325 } 326 327 for (i = 0; i < znode->child_cnt; i++) { 328 struct ubifs_branch *br = ubifs_idx_branch(c, idx, i); 329 struct ubifs_zbranch *zbr = &znode->zbranch[i]; 330 331 key_read(c, &br->key, &zbr->key); 332 zbr->lnum = le32_to_cpu(br->lnum); 333 zbr->offs = le32_to_cpu(br->offs); 334 zbr->len = le32_to_cpu(br->len); 335 ubifs_copy_hash(c, ubifs_branch_hash(c, br), zbr->hash); 336 zbr->znode = NULL; 337 338 /* Validate branch */ 339 340 if (zbr->lnum < c->main_first || 341 zbr->lnum >= c->leb_cnt || zbr->offs < 0 || 342 zbr->offs + zbr->len > c->leb_size || zbr->offs & 7) { 343 ubifs_err(c, "bad branch %d", i); 344 goto out_dump; 345 } 346 347 switch (key_type(c, &zbr->key)) { 348 case UBIFS_INO_KEY: 349 case UBIFS_DATA_KEY: 350 case UBIFS_DENT_KEY: 351 case UBIFS_XENT_KEY: 352 break; 353 default: 354 ubifs_err(c, "bad key type at slot %d: %d", 355 i, key_type(c, &zbr->key)); 356 goto out_dump; 357 } 358 359 if (znode->level) 360 continue; 361 362 type = key_type(c, &zbr->key); 363 if (c->ranges[type].max_len == 0) { 364 if (zbr->len != c->ranges[type].len) { 365 ubifs_err(c, "bad target node (type %d) length (%d)", 366 type, zbr->len); 367 ubifs_err(c, "have to be %d", c->ranges[type].len); 368 goto out_dump; 369 } 370 } else if (zbr->len < c->ranges[type].min_len || 371 zbr->len > c->ranges[type].max_len) { 372 ubifs_err(c, "bad target node (type %d) length (%d)", 373 type, zbr->len); 374 ubifs_err(c, "have to be in range of %d-%d", 375 c->ranges[type].min_len, 376 c->ranges[type].max_len); 377 goto out_dump; 378 } 379 } 380 381 /* 382 * Ensure that the next key is greater or equivalent to the 383 * previous one. 384 */ 385 for (i = 0; i < znode->child_cnt - 1; i++) { 386 const union ubifs_key *key1, *key2; 387 388 key1 = &znode->zbranch[i].key; 389 key2 = &znode->zbranch[i + 1].key; 390 391 cmp = keys_cmp(c, key1, key2); 392 if (cmp > 0) { 393 ubifs_err(c, "bad key order (keys %d and %d)", i, i + 1); 394 goto out_dump; 395 } else if (cmp == 0 && !is_hash_key(c, key1)) { 396 /* These can only be keys with colliding hash */ 397 ubifs_err(c, "keys %d and %d are not hashed but equivalent", 398 i, i + 1); 399 goto out_dump; 400 } 401 } 402 403 kfree(idx); 404 return 0; 405 406 out_dump: 407 ubifs_err(c, "bad indexing node at LEB %d:%d", lnum, offs); 408 ubifs_dump_node(c, idx, c->max_idx_node_sz); 409 kfree(idx); 410 return -EINVAL; 411 } 412 413 /** 414 * ubifs_load_znode - load znode to TNC cache. 415 * @c: UBIFS file-system description object 416 * @zbr: znode branch 417 * @parent: znode's parent 418 * @iip: index in parent 419 * 420 * This function loads znode pointed to by @zbr into the TNC cache and 421 * returns pointer to it in case of success and a negative error code in case 422 * of failure. 423 */ 424 struct ubifs_znode *ubifs_load_znode(struct ubifs_info *c, 425 struct ubifs_zbranch *zbr, 426 struct ubifs_znode *parent, int iip) 427 { 428 int err; 429 struct ubifs_znode *znode; 430 431 ubifs_assert(c, !zbr->znode); 432 /* 433 * A slab cache is not presently used for znodes because the znode size 434 * depends on the fanout which is stored in the superblock. 435 */ 436 znode = kzalloc(c->max_znode_sz, GFP_NOFS); 437 if (!znode) 438 return ERR_PTR(-ENOMEM); 439 440 err = read_znode(c, zbr, znode); 441 if (err) 442 goto out; 443 444 atomic_long_inc(&c->clean_zn_cnt); 445 446 /* 447 * Increment the global clean znode counter as well. It is OK that 448 * global and per-FS clean znode counters may be inconsistent for some 449 * short time (because we might be preempted at this point), the global 450 * one is only used in shrinker. 451 */ 452 atomic_long_inc(&ubifs_clean_zn_cnt); 453 454 zbr->znode = znode; 455 znode->parent = parent; 456 znode->time = ktime_get_seconds(); 457 znode->iip = iip; 458 459 return znode; 460 461 out: 462 kfree(znode); 463 return ERR_PTR(err); 464 } 465 466 /** 467 * ubifs_tnc_read_node - read a leaf node from the flash media. 468 * @c: UBIFS file-system description object 469 * @zbr: key and position of the node 470 * @node: node is returned here 471 * 472 * This function reads a node defined by @zbr from the flash media. Returns 473 * zero in case of success or a negative error code in case of failure. 474 */ 475 int ubifs_tnc_read_node(struct ubifs_info *c, struct ubifs_zbranch *zbr, 476 void *node) 477 { 478 union ubifs_key key1, *key = &zbr->key; 479 int err, type = key_type(c, key); 480 struct ubifs_wbuf *wbuf; 481 482 /* 483 * 'zbr' has to point to on-flash node. The node may sit in a bud and 484 * may even be in a write buffer, so we have to take care about this. 485 */ 486 wbuf = ubifs_get_wbuf(c, zbr->lnum); 487 if (wbuf) 488 err = ubifs_read_node_wbuf(wbuf, node, type, zbr->len, 489 zbr->lnum, zbr->offs); 490 else 491 err = ubifs_read_node(c, node, type, zbr->len, zbr->lnum, 492 zbr->offs); 493 494 if (err) { 495 dbg_tnck(key, "key "); 496 return err; 497 } 498 499 /* Make sure the key of the read node is correct */ 500 key_read(c, node + UBIFS_KEY_OFFSET, &key1); 501 if (!keys_eq(c, key, &key1)) { 502 ubifs_err(c, "bad key in node at LEB %d:%d", 503 zbr->lnum, zbr->offs); 504 dbg_tnck(key, "looked for key "); 505 dbg_tnck(&key1, "but found node's key "); 506 ubifs_dump_node(c, node, zbr->len); 507 return -EINVAL; 508 } 509 510 err = ubifs_node_check_hash(c, node, zbr->hash); 511 if (err) { 512 ubifs_bad_hash(c, node, zbr->hash, zbr->lnum, zbr->offs); 513 return err; 514 } 515 516 return 0; 517 } 518