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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * This file is part of UBIFS.4 *5 * Copyright (C) 2006-2008 Nokia Corporation.6 *7 * Authors: Adrian Hunter8 * Artem Bityutskiy (Битюцкий Артём)9 */10 11/*12 * This file contains miscelanious TNC-related functions shared betweend13 * different files. This file does not form any logically separate TNC14 * sub-system. The file was created because there is a lot of TNC code and15 * 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 object23 * @zr: root of the subtree to traverse24 * @znode: previous znode25 *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 */29struct 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 to55 * 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 lower69 * level ('level_search'). As we are here70 * again, it just does not exist. Or all levels71 * 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 not96 * 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 object113 * @znode: znode to search in114 * @key: key to search for115 * @n: znode branch slot number is returned here116 *117 * This is a helper function which search branch with key @key in @znode using118 * binary search. The result of the search may be:119 * o exact match, then %1 is returned, and the slot number of the branch is120 * stored in @n;121 * o no exact match, then %0 is returned and the slot number of the left122 * closest branch is returned in @n; the slot if all keys in this znode are123 * greater than @key, then %-1 is returned in @n.124 */125int 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 else155 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 is167 * ignored.168 */169struct 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 object189 * @znode: previous znode190 *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 */194struct 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 object216 * @znode: znode defining subtree to destroy217 *218 * This function destroys subtree of the TNC tree. Returns number of clean219 * znodes in the subtree.220 */221long 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 object256 *257 * This function destroys the whole TNC tree and updates clean global znode258 * count.259 */260void 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 object278 * @zzbr: the zbranch describing the node to read279 * @znode: znode to read to280 *281 * This function reads an indexing node from the flash media and fills znode282 * with the read data. Returns zero in case of success and a negative error283 * code in case of failure. The read indexing node is validated and if anything284 * is wrong with it, this function prints complaint messages and returns285 * %-EINVAL.286 */287static 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 err = 1;325 goto out_dump;326 }327 328 for (i = 0; i < znode->child_cnt; i++) {329 struct ubifs_branch *br = ubifs_idx_branch(c, idx, i);330 struct ubifs_zbranch *zbr = &znode->zbranch[i];331 332 key_read(c, &br->key, &zbr->key);333 zbr->lnum = le32_to_cpu(br->lnum);334 zbr->offs = le32_to_cpu(br->offs);335 zbr->len = le32_to_cpu(br->len);336 ubifs_copy_hash(c, ubifs_branch_hash(c, br), zbr->hash);337 zbr->znode = NULL;338 339 /* Validate branch */340 341 if (zbr->lnum < c->main_first ||342 zbr->lnum >= c->leb_cnt || zbr->offs < 0 ||343 zbr->offs + zbr->len > c->leb_size || zbr->offs & 7) {344 ubifs_err(c, "bad branch %d", i);345 err = 2;346 goto out_dump;347 }348 349 switch (key_type(c, &zbr->key)) {350 case UBIFS_INO_KEY:351 case UBIFS_DATA_KEY:352 case UBIFS_DENT_KEY:353 case UBIFS_XENT_KEY:354 break;355 default:356 ubifs_err(c, "bad key type at slot %d: %d",357 i, key_type(c, &zbr->key));358 err = 3;359 goto out_dump;360 }361 362 if (znode->level)363 continue;364 365 type = key_type(c, &zbr->key);366 if (c->ranges[type].max_len == 0) {367 if (zbr->len != c->ranges[type].len) {368 ubifs_err(c, "bad target node (type %d) length (%d)",369 type, zbr->len);370 ubifs_err(c, "have to be %d", c->ranges[type].len);371 err = 4;372 goto out_dump;373 }374 } else if (zbr->len < c->ranges[type].min_len ||375 zbr->len > c->ranges[type].max_len) {376 ubifs_err(c, "bad target node (type %d) length (%d)",377 type, zbr->len);378 ubifs_err(c, "have to be in range of %d-%d",379 c->ranges[type].min_len,380 c->ranges[type].max_len);381 err = 5;382 goto out_dump;383 }384 }385 386 /*387 * Ensure that the next key is greater or equivalent to the388 * previous one.389 */390 for (i = 0; i < znode->child_cnt - 1; i++) {391 const union ubifs_key *key1, *key2;392 393 key1 = &znode->zbranch[i].key;394 key2 = &znode->zbranch[i + 1].key;395 396 cmp = keys_cmp(c, key1, key2);397 if (cmp > 0) {398 ubifs_err(c, "bad key order (keys %d and %d)", i, i + 1);399 err = 6;400 goto out_dump;401 } else if (cmp == 0 && !is_hash_key(c, key1)) {402 /* These can only be keys with colliding hash */403 ubifs_err(c, "keys %d and %d are not hashed but equivalent",404 i, i + 1);405 err = 7;406 goto out_dump;407 }408 }409 410 kfree(idx);411 return 0;412 413out_dump:414 ubifs_err(c, "bad indexing node at LEB %d:%d, error %d", lnum, offs, err);415 ubifs_dump_node(c, idx, c->max_idx_node_sz);416 kfree(idx);417 return -EINVAL;418}419 420/**421 * ubifs_load_znode - load znode to TNC cache.422 * @c: UBIFS file-system description object423 * @zbr: znode branch424 * @parent: znode's parent425 * @iip: index in parent426 *427 * This function loads znode pointed to by @zbr into the TNC cache and428 * returns pointer to it in case of success and a negative error code in case429 * of failure.430 */431struct ubifs_znode *ubifs_load_znode(struct ubifs_info *c,432 struct ubifs_zbranch *zbr,433 struct ubifs_znode *parent, int iip)434{435 int err;436 struct ubifs_znode *znode;437 438 ubifs_assert(c, !zbr->znode);439 /*440 * A slab cache is not presently used for znodes because the znode size441 * depends on the fanout which is stored in the superblock.442 */443 znode = kzalloc(c->max_znode_sz, GFP_NOFS);444 if (!znode)445 return ERR_PTR(-ENOMEM);446 447 err = read_znode(c, zbr, znode);448 if (err)449 goto out;450 451 atomic_long_inc(&c->clean_zn_cnt);452 453 /*454 * Increment the global clean znode counter as well. It is OK that455 * global and per-FS clean znode counters may be inconsistent for some456 * short time (because we might be preempted at this point), the global457 * one is only used in shrinker.458 */459 atomic_long_inc(&ubifs_clean_zn_cnt);460 461 zbr->znode = znode;462 znode->parent = parent;463 znode->time = ktime_get_seconds();464 znode->iip = iip;465 466 return znode;467 468out:469 kfree(znode);470 return ERR_PTR(err);471}472 473/**474 * ubifs_tnc_read_node - read a leaf node from the flash media.475 * @c: UBIFS file-system description object476 * @zbr: key and position of the node477 * @node: node is returned here478 *479 * This function reads a node defined by @zbr from the flash media. Returns480 * zero in case of success or a negative error code in case of failure.481 */482int ubifs_tnc_read_node(struct ubifs_info *c, struct ubifs_zbranch *zbr,483 void *node)484{485 union ubifs_key key1, *key = &zbr->key;486 int err, type = key_type(c, key);487 struct ubifs_wbuf *wbuf;488 489 /*490 * 'zbr' has to point to on-flash node. The node may sit in a bud and491 * may even be in a write buffer, so we have to take care about this.492 */493 wbuf = ubifs_get_wbuf(c, zbr->lnum);494 if (wbuf)495 err = ubifs_read_node_wbuf(wbuf, node, type, zbr->len,496 zbr->lnum, zbr->offs);497 else498 err = ubifs_read_node(c, node, type, zbr->len, zbr->lnum,499 zbr->offs);500 501 if (err) {502 dbg_tnck(key, "key ");503 return err;504 }505 506 /* Make sure the key of the read node is correct */507 key_read(c, node + UBIFS_KEY_OFFSET, &key1);508 if (!keys_eq(c, key, &key1)) {509 ubifs_err(c, "bad key in node at LEB %d:%d",510 zbr->lnum, zbr->offs);511 dbg_tnck(key, "looked for key ");512 dbg_tnck(&key1, "but found node's key ");513 ubifs_dump_node(c, node, zbr->len);514 return -EINVAL;515 }516 517 err = ubifs_node_check_hash(c, node, zbr->hash);518 if (err) {519 ubifs_bad_hash(c, node, zbr->hash, zbr->lnum, zbr->offs);520 return err;521 }522 523 return 0;524}525