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