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(znode: zr, start: 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(znode: zr, start: 0); |
78 | ubifs_assert(c, znode); |
79 | } |
80 | |
81 | /* Switch to the next index */ |
82 | zn = ubifs_tnc_find_child(znode: znode->parent, start: 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(znode: zn, start: 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, key1: key, key2: &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, start: 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: znode->parent, start: 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(znode: 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(znode: zn->zbranch[n].znode)) |
236 | clean_freed += 1; |
237 | |
238 | cond_resched(); |
239 | kfree(objp: zn->zbranch[n].znode); |
240 | } |
241 | |
242 | if (zn == znode) { |
243 | if (!ubifs_zn_dirty(znode: zn)) |
244 | clean_freed += 1; |
245 | kfree(objp: zn); |
246 | return clean_freed; |
247 | } |
248 | |
249 | zn = ubifs_tnc_postorder_next(c, znode: 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(v: &c->clean_zn_cnt); |
268 | freed = ubifs_destroy_tnc_subtree(c, znode: c->zroot.znode); |
269 | ubifs_assert(c, freed == n); |
270 | atomic_long_sub(i: n, v: &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(size: c->max_idx_node_sz, GFP_NOFS); |
297 | if (!idx) |
298 | return -ENOMEM; |
299 | |
300 | err = ubifs_read_node(c, buf: idx, type: UBIFS_IDX_NODE, len, lnum, offs); |
301 | if (err < 0) { |
302 | kfree(objp: idx); |
303 | return err; |
304 | } |
305 | |
306 | err = ubifs_node_check_hash(c, buf: idx, expected: zzbr->hash); |
307 | if (err) { |
308 | ubifs_bad_hash(c, node: idx, hash: zzbr->hash, lnum, offs); |
309 | kfree(objp: 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, fmt: "current fanout %d, branch count %d" , |
321 | c->fanout, znode->child_cnt); |
322 | ubifs_err(c, fmt: "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, bnum: i); |
330 | struct ubifs_zbranch *zbr = &znode->zbranch[i]; |
331 | |
332 | key_read(c, from: &br->key, to: &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, from: ubifs_branch_hash(c, br), to: 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, fmt: "bad branch %d" , i); |
345 | err = 2; |
346 | goto out_dump; |
347 | } |
348 | |
349 | switch (key_type(c, key: &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, fmt: "bad key type at slot %d: %d" , |
357 | i, key_type(c, key: &zbr->key)); |
358 | err = 3; |
359 | goto out_dump; |
360 | } |
361 | |
362 | if (znode->level) |
363 | continue; |
364 | |
365 | type = key_type(c, key: &zbr->key); |
366 | if (c->ranges[type].max_len == 0) { |
367 | if (zbr->len != c->ranges[type].len) { |
368 | ubifs_err(c, fmt: "bad target node (type %d) length (%d)" , |
369 | type, zbr->len); |
370 | ubifs_err(c, fmt: "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, fmt: "bad target node (type %d) length (%d)" , |
377 | type, zbr->len); |
378 | ubifs_err(c, fmt: "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 the |
388 | * 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, fmt: "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, key: key1)) { |
402 | /* These can only be keys with colliding hash */ |
403 | ubifs_err(c, fmt: "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(objp: idx); |
411 | return 0; |
412 | |
413 | out_dump: |
414 | ubifs_err(c, fmt: "bad indexing node at LEB %d:%d, error %d" , lnum, offs, err); |
415 | ubifs_dump_node(c, node: idx, node_len: c->max_idx_node_sz); |
416 | kfree(objp: idx); |
417 | return -EINVAL; |
418 | } |
419 | |
420 | /** |
421 | * ubifs_load_znode - load znode to TNC cache. |
422 | * @c: UBIFS file-system description object |
423 | * @zbr: znode branch |
424 | * @parent: znode's parent |
425 | * @iip: index in parent |
426 | * |
427 | * This function loads znode pointed to by @zbr into the TNC cache and |
428 | * returns pointer to it in case of success and a negative error code in case |
429 | * of failure. |
430 | */ |
431 | struct 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 size |
441 | * depends on the fanout which is stored in the superblock. |
442 | */ |
443 | znode = kzalloc(size: c->max_znode_sz, GFP_NOFS); |
444 | if (!znode) |
445 | return ERR_PTR(error: -ENOMEM); |
446 | |
447 | err = read_znode(c, zzbr: zbr, znode); |
448 | if (err) |
449 | goto out; |
450 | |
451 | atomic_long_inc(v: &c->clean_zn_cnt); |
452 | |
453 | /* |
454 | * Increment the global clean znode counter as well. It is OK that |
455 | * global and per-FS clean znode counters may be inconsistent for some |
456 | * short time (because we might be preempted at this point), the global |
457 | * one is only used in shrinker. |
458 | */ |
459 | atomic_long_inc(v: &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 | |
468 | out: |
469 | kfree(objp: znode); |
470 | return ERR_PTR(error: err); |
471 | } |
472 | |
473 | /** |
474 | * ubifs_tnc_read_node - read a leaf node from the flash media. |
475 | * @c: UBIFS file-system description object |
476 | * @zbr: key and position of the node |
477 | * @node: node is returned here |
478 | * |
479 | * This function reads a node defined by @zbr from the flash media. Returns |
480 | * zero in case of success or a negative error code in case of failure. |
481 | */ |
482 | int 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 and |
491 | * may even be in a write buffer, so we have to take care about this. |
492 | */ |
493 | wbuf = ubifs_get_wbuf(c, lnum: zbr->lnum); |
494 | if (wbuf) |
495 | err = ubifs_read_node_wbuf(wbuf, buf: node, type, len: zbr->len, |
496 | lnum: zbr->lnum, offs: zbr->offs); |
497 | else |
498 | err = ubifs_read_node(c, buf: node, type, len: zbr->len, lnum: zbr->lnum, |
499 | offs: 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, from: node + UBIFS_KEY_OFFSET, to: &key1); |
508 | if (!keys_eq(c, key1: key, key2: &key1)) { |
509 | ubifs_err(c, fmt: "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, node_len: zbr->len); |
514 | return -EINVAL; |
515 | } |
516 | |
517 | err = ubifs_node_check_hash(c, buf: node, expected: zbr->hash); |
518 | if (err) { |
519 | ubifs_bad_hash(c, node, hash: zbr->hash, lnum: zbr->lnum, offs: zbr->offs); |
520 | return err; |
521 | } |
522 | |
523 | return 0; |
524 | } |
525 | |