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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: Adrian Hunter |
20 | * Artem Bityutskiy (Битюцкий Артём) |
21 | */ |
22 | |
23 | /* |
24 | * This file implements TNC (Tree Node Cache) which caches indexing nodes of |
25 | * the UBIFS B-tree. |
26 | * |
27 | * At the moment the locking rules of the TNC tree are quite simple and |
28 | * straightforward. We just have a mutex and lock it when we traverse the |
29 | * tree. If a znode is not in memory, we read it from flash while still having |
30 | * the mutex locked. |
31 | */ |
32 | |
33 | #include <linux/crc32.h> |
34 | #include <linux/slab.h> |
35 | #include "ubifs.h" |
36 | |
37 | /* |
38 | * Returned codes of 'matches_name()' and 'fallible_matches_name()' functions. |
39 | * @NAME_LESS: name corresponding to the first argument is less than second |
40 | * @NAME_MATCHES: names match |
41 | * @NAME_GREATER: name corresponding to the second argument is greater than |
42 | * first |
43 | * @NOT_ON_MEDIA: node referred by zbranch does not exist on the media |
44 | * |
45 | * These constants were introduce to improve readability. |
46 | */ |
47 | enum { |
48 | NAME_LESS = 0, |
49 | NAME_MATCHES = 1, |
50 | NAME_GREATER = 2, |
51 | NOT_ON_MEDIA = 3, |
52 | }; |
53 | |
54 | /** |
55 | * insert_old_idx - record an index node obsoleted since the last commit start. |
56 | * @c: UBIFS file-system description object |
57 | * @lnum: LEB number of obsoleted index node |
58 | * @offs: offset of obsoleted index node |
59 | * |
60 | * Returns %0 on success, and a negative error code on failure. |
61 | * |
62 | * For recovery, there must always be a complete intact version of the index on |
63 | * flash at all times. That is called the "old index". It is the index as at the |
64 | * time of the last successful commit. Many of the index nodes in the old index |
65 | * may be dirty, but they must not be erased until the next successful commit |
66 | * (at which point that index becomes the old index). |
67 | * |
68 | * That means that the garbage collection and the in-the-gaps method of |
69 | * committing must be able to determine if an index node is in the old index. |
70 | * Most of the old index nodes can be found by looking up the TNC using the |
71 | * 'lookup_znode()' function. However, some of the old index nodes may have |
72 | * been deleted from the current index or may have been changed so much that |
73 | * they cannot be easily found. In those cases, an entry is added to an RB-tree. |
74 | * That is what this function does. The RB-tree is ordered by LEB number and |
75 | * offset because they uniquely identify the old index node. |
76 | */ |
77 | static int insert_old_idx(struct ubifs_info *c, int lnum, int offs) |
78 | { |
79 | struct ubifs_old_idx *old_idx, *o; |
80 | struct rb_node **p, *parent = NULL; |
81 | |
82 | old_idx = kmalloc(sizeof(struct ubifs_old_idx), GFP_NOFS); |
83 | if (unlikely(!old_idx)) |
84 | return -ENOMEM; |
85 | old_idx->lnum = lnum; |
86 | old_idx->offs = offs; |
87 | |
88 | p = &c->old_idx.rb_node; |
89 | while (*p) { |
90 | parent = *p; |
91 | o = rb_entry(parent, struct ubifs_old_idx, rb); |
92 | if (lnum < o->lnum) |
93 | p = &(*p)->rb_left; |
94 | else if (lnum > o->lnum) |
95 | p = &(*p)->rb_right; |
96 | else if (offs < o->offs) |
97 | p = &(*p)->rb_left; |
98 | else if (offs > o->offs) |
99 | p = &(*p)->rb_right; |
100 | else { |
101 | ubifs_err("old idx added twice!"); |
102 | kfree(old_idx); |
103 | return 0; |
104 | } |
105 | } |
106 | rb_link_node(&old_idx->rb, parent, p); |
107 | rb_insert_color(&old_idx->rb, &c->old_idx); |
108 | return 0; |
109 | } |
110 | |
111 | /** |
112 | * insert_old_idx_znode - record a znode obsoleted since last commit start. |
113 | * @c: UBIFS file-system description object |
114 | * @znode: znode of obsoleted index node |
115 | * |
116 | * Returns %0 on success, and a negative error code on failure. |
117 | */ |
118 | int insert_old_idx_znode(struct ubifs_info *c, struct ubifs_znode *znode) |
119 | { |
120 | if (znode->parent) { |
121 | struct ubifs_zbranch *zbr; |
122 | |
123 | zbr = &znode->parent->zbranch[znode->iip]; |
124 | if (zbr->len) |
125 | return insert_old_idx(c, zbr->lnum, zbr->offs); |
126 | } else |
127 | if (c->zroot.len) |
128 | return insert_old_idx(c, c->zroot.lnum, |
129 | c->zroot.offs); |
130 | return 0; |
131 | } |
132 | |
133 | /** |
134 | * ins_clr_old_idx_znode - record a znode obsoleted since last commit start. |
135 | * @c: UBIFS file-system description object |
136 | * @znode: znode of obsoleted index node |
137 | * |
138 | * Returns %0 on success, and a negative error code on failure. |
139 | */ |
140 | static int ins_clr_old_idx_znode(struct ubifs_info *c, |
141 | struct ubifs_znode *znode) |
142 | { |
143 | int err; |
144 | |
145 | if (znode->parent) { |
146 | struct ubifs_zbranch *zbr; |
147 | |
148 | zbr = &znode->parent->zbranch[znode->iip]; |
149 | if (zbr->len) { |
150 | err = insert_old_idx(c, zbr->lnum, zbr->offs); |
151 | if (err) |
152 | return err; |
153 | zbr->lnum = 0; |
154 | zbr->offs = 0; |
155 | zbr->len = 0; |
156 | } |
157 | } else |
158 | if (c->zroot.len) { |
159 | err = insert_old_idx(c, c->zroot.lnum, c->zroot.offs); |
160 | if (err) |
161 | return err; |
162 | c->zroot.lnum = 0; |
163 | c->zroot.offs = 0; |
164 | c->zroot.len = 0; |
165 | } |
166 | return 0; |
167 | } |
168 | |
169 | /** |
170 | * destroy_old_idx - destroy the old_idx RB-tree. |
171 | * @c: UBIFS file-system description object |
172 | * |
173 | * During start commit, the old_idx RB-tree is used to avoid overwriting index |
174 | * nodes that were in the index last commit but have since been deleted. This |
175 | * is necessary for recovery i.e. the old index must be kept intact until the |
176 | * new index is successfully written. The old-idx RB-tree is used for the |
177 | * in-the-gaps method of writing index nodes and is destroyed every commit. |
178 | */ |
179 | void destroy_old_idx(struct ubifs_info *c) |
180 | { |
181 | struct rb_node *this = c->old_idx.rb_node; |
182 | struct ubifs_old_idx *old_idx; |
183 | |
184 | while (this) { |
185 | if (this->rb_left) { |
186 | this = this->rb_left; |
187 | continue; |
188 | } else if (this->rb_right) { |
189 | this = this->rb_right; |
190 | continue; |
191 | } |
192 | old_idx = rb_entry(this, struct ubifs_old_idx, rb); |
193 | this = rb_parent(this); |
194 | if (this) { |
195 | if (this->rb_left == &old_idx->rb) |
196 | this->rb_left = NULL; |
197 | else |
198 | this->rb_right = NULL; |
199 | } |
200 | kfree(old_idx); |
201 | } |
202 | c->old_idx = RB_ROOT; |
203 | } |
204 | |
205 | /** |
206 | * copy_znode - copy a dirty znode. |
207 | * @c: UBIFS file-system description object |
208 | * @znode: znode to copy |
209 | * |
210 | * A dirty znode being committed may not be changed, so it is copied. |
211 | */ |
212 | static struct ubifs_znode *copy_znode(struct ubifs_info *c, |
213 | struct ubifs_znode *znode) |
214 | { |
215 | struct ubifs_znode *zn; |
216 | |
217 | zn = kmalloc(c->max_znode_sz, GFP_NOFS); |
218 | if (unlikely(!zn)) |
219 | return ERR_PTR(-ENOMEM); |
220 | |
221 | memcpy(zn, znode, c->max_znode_sz); |
222 | zn->cnext = NULL; |
223 | __set_bit(DIRTY_ZNODE, &zn->flags); |
224 | __clear_bit(COW_ZNODE, &zn->flags); |
225 | |
226 | ubifs_assert(!test_bit(OBSOLETE_ZNODE, &znode->flags)); |
227 | __set_bit(OBSOLETE_ZNODE, &znode->flags); |
228 | |
229 | if (znode->level != 0) { |
230 | int i; |
231 | const int n = zn->child_cnt; |
232 | |
233 | /* The children now have new parent */ |
234 | for (i = 0; i < n; i++) { |
235 | struct ubifs_zbranch *zbr = &zn->zbranch[i]; |
236 | |
237 | if (zbr->znode) |
238 | zbr->znode->parent = zn; |
239 | } |
240 | } |
241 | |
242 | atomic_long_inc(&c->dirty_zn_cnt); |
243 | return zn; |
244 | } |
245 | |
246 | /** |
247 | * add_idx_dirt - add dirt due to a dirty znode. |
248 | * @c: UBIFS file-system description object |
249 | * @lnum: LEB number of index node |
250 | * @dirt: size of index node |
251 | * |
252 | * This function updates lprops dirty space and the new size of the index. |
253 | */ |
254 | static int add_idx_dirt(struct ubifs_info *c, int lnum, int dirt) |
255 | { |
256 | c->calc_idx_sz -= ALIGN(dirt, 8); |
257 | return ubifs_add_dirt(c, lnum, dirt); |
258 | } |
259 | |
260 | /** |
261 | * dirty_cow_znode - ensure a znode is not being committed. |
262 | * @c: UBIFS file-system description object |
263 | * @zbr: branch of znode to check |
264 | * |
265 | * Returns dirtied znode on success or negative error code on failure. |
266 | */ |
267 | static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c, |
268 | struct ubifs_zbranch *zbr) |
269 | { |
270 | struct ubifs_znode *znode = zbr->znode; |
271 | struct ubifs_znode *zn; |
272 | int err; |
273 | |
274 | if (!test_bit(COW_ZNODE, &znode->flags)) { |
275 | /* znode is not being committed */ |
276 | if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) { |
277 | atomic_long_inc(&c->dirty_zn_cnt); |
278 | atomic_long_dec(&c->clean_zn_cnt); |
279 | atomic_long_dec(&ubifs_clean_zn_cnt); |
280 | err = add_idx_dirt(c, zbr->lnum, zbr->len); |
281 | if (unlikely(err)) |
282 | return ERR_PTR(err); |
283 | } |
284 | return znode; |
285 | } |
286 | |
287 | zn = copy_znode(c, znode); |
288 | if (IS_ERR(zn)) |
289 | return zn; |
290 | |
291 | if (zbr->len) { |
292 | err = insert_old_idx(c, zbr->lnum, zbr->offs); |
293 | if (unlikely(err)) |
294 | return ERR_PTR(err); |
295 | err = add_idx_dirt(c, zbr->lnum, zbr->len); |
296 | } else |
297 | err = 0; |
298 | |
299 | zbr->znode = zn; |
300 | zbr->lnum = 0; |
301 | zbr->offs = 0; |
302 | zbr->len = 0; |
303 | |
304 | if (unlikely(err)) |
305 | return ERR_PTR(err); |
306 | return zn; |
307 | } |
308 | |
309 | /** |
310 | * lnc_add - add a leaf node to the leaf node cache. |
311 | * @c: UBIFS file-system description object |
312 | * @zbr: zbranch of leaf node |
313 | * @node: leaf node |
314 | * |
315 | * Leaf nodes are non-index nodes directory entry nodes or data nodes. The |
316 | * purpose of the leaf node cache is to save re-reading the same leaf node over |
317 | * and over again. Most things are cached by VFS, however the file system must |
318 | * cache directory entries for readdir and for resolving hash collisions. The |
319 | * present implementation of the leaf node cache is extremely simple, and |
320 | * allows for error returns that are not used but that may be needed if a more |
321 | * complex implementation is created. |
322 | * |
323 | * Note, this function does not add the @node object to LNC directly, but |
324 | * allocates a copy of the object and adds the copy to LNC. The reason for this |
325 | * is that @node has been allocated outside of the TNC subsystem and will be |
326 | * used with @c->tnc_mutex unlock upon return from the TNC subsystem. But LNC |
327 | * may be changed at any time, e.g. freed by the shrinker. |
328 | */ |
329 | static int lnc_add(struct ubifs_info *c, struct ubifs_zbranch *zbr, |
330 | const void *node) |
331 | { |
332 | int err; |
333 | void *lnc_node; |
334 | const struct ubifs_dent_node *dent = node; |
335 | |
336 | ubifs_assert(!zbr->leaf); |
337 | ubifs_assert(zbr->len != 0); |
338 | ubifs_assert(is_hash_key(c, &zbr->key)); |
339 | |
340 | err = ubifs_validate_entry(c, dent); |
341 | if (err) { |
342 | dbg_dump_stack(); |
343 | dbg_dump_node(c, dent); |
344 | return err; |
345 | } |
346 | |
347 | lnc_node = kmalloc(zbr->len, GFP_NOFS); |
348 | if (!lnc_node) |
349 | /* We don't have to have the cache, so no error */ |
350 | return 0; |
351 | |
352 | memcpy(lnc_node, node, zbr->len); |
353 | zbr->leaf = lnc_node; |
354 | return 0; |
355 | } |
356 | |
357 | /** |
358 | * lnc_add_directly - add a leaf node to the leaf-node-cache. |
359 | * @c: UBIFS file-system description object |
360 | * @zbr: zbranch of leaf node |
361 | * @node: leaf node |
362 | * |
363 | * This function is similar to 'lnc_add()', but it does not create a copy of |
364 | * @node but inserts @node to TNC directly. |
365 | */ |
366 | static int lnc_add_directly(struct ubifs_info *c, struct ubifs_zbranch *zbr, |
367 | void *node) |
368 | { |
369 | int err; |
370 | |
371 | ubifs_assert(!zbr->leaf); |
372 | ubifs_assert(zbr->len != 0); |
373 | |
374 | err = ubifs_validate_entry(c, node); |
375 | if (err) { |
376 | dbg_dump_stack(); |
377 | dbg_dump_node(c, node); |
378 | return err; |
379 | } |
380 | |
381 | zbr->leaf = node; |
382 | return 0; |
383 | } |
384 | |
385 | /** |
386 | * lnc_free - remove a leaf node from the leaf node cache. |
387 | * @zbr: zbranch of leaf node |
388 | * @node: leaf node |
389 | */ |
390 | static void lnc_free(struct ubifs_zbranch *zbr) |
391 | { |
392 | if (!zbr->leaf) |
393 | return; |
394 | kfree(zbr->leaf); |
395 | zbr->leaf = NULL; |
396 | } |
397 | |
398 | /** |
399 | * tnc_read_node_nm - read a "hashed" leaf node. |
400 | * @c: UBIFS file-system description object |
401 | * @zbr: key and position of the node |
402 | * @node: node is returned here |
403 | * |
404 | * This function reads a "hashed" node defined by @zbr from the leaf node cache |
405 | * (in it is there) or from the hash media, in which case the node is also |
406 | * added to LNC. Returns zero in case of success or a negative negative error |
407 | * code in case of failure. |
408 | */ |
409 | static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr, |
410 | void *node) |
411 | { |
412 | int err; |
413 | |
414 | ubifs_assert(is_hash_key(c, &zbr->key)); |
415 | |
416 | if (zbr->leaf) { |
417 | /* Read from the leaf node cache */ |
418 | ubifs_assert(zbr->len != 0); |
419 | memcpy(node, zbr->leaf, zbr->len); |
420 | return 0; |
421 | } |
422 | |
423 | err = ubifs_tnc_read_node(c, zbr, node); |
424 | if (err) |
425 | return err; |
426 | |
427 | /* Add the node to the leaf node cache */ |
428 | err = lnc_add(c, zbr, node); |
429 | return err; |
430 | } |
431 | |
432 | /** |
433 | * try_read_node - read a node if it is a node. |
434 | * @c: UBIFS file-system description object |
435 | * @buf: buffer to read to |
436 | * @type: node type |
437 | * @len: node length (not aligned) |
438 | * @lnum: LEB number of node to read |
439 | * @offs: offset of node to read |
440 | * |
441 | * This function tries to read a node of known type and length, checks it and |
442 | * stores it in @buf. This function returns %1 if a node is present and %0 if |
443 | * a node is not present. A negative error code is returned for I/O errors. |
444 | * This function performs that same function as ubifs_read_node except that |
445 | * it does not require that there is actually a node present and instead |
446 | * the return code indicates if a node was read. |
447 | * |
448 | * Note, this function does not check CRC of data nodes if @c->no_chk_data_crc |
449 | * is true (it is controlled by corresponding mount option). However, if |
450 | * @c->mounting or @c->remounting_rw is true (we are mounting or re-mounting to |
451 | * R/W mode), @c->no_chk_data_crc is ignored and CRC is checked. This is |
452 | * because during mounting or re-mounting from R/O mode to R/W mode we may read |
453 | * journal nodes (when replying the journal or doing the recovery) and the |
454 | * journal nodes may potentially be corrupted, so checking is required. |
455 | */ |
456 | static int try_read_node(const struct ubifs_info *c, void *buf, int type, |
457 | int len, int lnum, int offs) |
458 | { |
459 | int err, node_len; |
460 | struct ubifs_ch *ch = buf; |
461 | uint32_t crc, node_crc; |
462 | |
463 | dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len); |
464 | |
465 | err = ubi_read(c->ubi, lnum, buf, offs, len); |
466 | if (err) { |
467 | ubifs_err("cannot read node type %d from LEB %d:%d, error %d", |
468 | type, lnum, offs, err); |
469 | return err; |
470 | } |
471 | |
472 | if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC) |
473 | return 0; |
474 | |
475 | if (ch->node_type != type) |
476 | return 0; |
477 | |
478 | node_len = le32_to_cpu(ch->len); |
479 | if (node_len != len) |
480 | return 0; |
481 | |
482 | if (type == UBIFS_DATA_NODE && c->no_chk_data_crc && !c->mounting && |
483 | !c->remounting_rw) |
484 | return 1; |
485 | |
486 | crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8); |
487 | node_crc = le32_to_cpu(ch->crc); |
488 | if (crc != node_crc) |
489 | return 0; |
490 | |
491 | return 1; |
492 | } |
493 | |
494 | /** |
495 | * fallible_read_node - try to read a leaf node. |
496 | * @c: UBIFS file-system description object |
497 | * @key: key of node to read |
498 | * @zbr: position of node |
499 | * @node: node returned |
500 | * |
501 | * This function tries to read a node and returns %1 if the node is read, %0 |
502 | * if the node is not present, and a negative error code in the case of error. |
503 | */ |
504 | static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key, |
505 | struct ubifs_zbranch *zbr, void *node) |
506 | { |
507 | int ret; |
508 | |
509 | dbg_tnc("LEB %d:%d, key %s", zbr->lnum, zbr->offs, DBGKEY(key)); |
510 | |
511 | ret = try_read_node(c, node, key_type(c, key), zbr->len, zbr->lnum, |
512 | zbr->offs); |
513 | if (ret == 1) { |
514 | union ubifs_key node_key; |
515 | struct ubifs_dent_node *dent = node; |
516 | |
517 | /* All nodes have key in the same place */ |
518 | key_read(c, &dent->key, &node_key); |
519 | if (keys_cmp(c, key, &node_key) != 0) |
520 | ret = 0; |
521 | } |
522 | if (ret == 0 && c->replaying) |
523 | dbg_mnt("dangling branch LEB %d:%d len %d, key %s", |
524 | zbr->lnum, zbr->offs, zbr->len, DBGKEY(key)); |
525 | return ret; |
526 | } |
527 | |
528 | /** |
529 | * matches_name - determine if a direntry or xattr entry matches a given name. |
530 | * @c: UBIFS file-system description object |
531 | * @zbr: zbranch of dent |
532 | * @nm: name to match |
533 | * |
534 | * This function checks if xentry/direntry referred by zbranch @zbr matches name |
535 | * @nm. Returns %NAME_MATCHES if it does, %NAME_LESS if the name referred by |
536 | * @zbr is less than @nm, and %NAME_GREATER if it is greater than @nm. In case |
537 | * of failure, a negative error code is returned. |
538 | */ |
539 | static int matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr, |
540 | const struct qstr *nm) |
541 | { |
542 | struct ubifs_dent_node *dent; |
543 | int nlen, err; |
544 | |
545 | /* If possible, match against the dent in the leaf node cache */ |
546 | if (!zbr->leaf) { |
547 | dent = kmalloc(zbr->len, GFP_NOFS); |
548 | if (!dent) |
549 | return -ENOMEM; |
550 | |
551 | err = ubifs_tnc_read_node(c, zbr, dent); |
552 | if (err) |
553 | goto out_free; |
554 | |
555 | /* Add the node to the leaf node cache */ |
556 | err = lnc_add_directly(c, zbr, dent); |
557 | if (err) |
558 | goto out_free; |
559 | } else |
560 | dent = zbr->leaf; |
561 | |
562 | nlen = le16_to_cpu(dent->nlen); |
563 | err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len)); |
564 | if (err == 0) { |
565 | if (nlen == nm->len) |
566 | return NAME_MATCHES; |
567 | else if (nlen < nm->len) |
568 | return NAME_LESS; |
569 | else |
570 | return NAME_GREATER; |
571 | } else if (err < 0) |
572 | return NAME_LESS; |
573 | else |
574 | return NAME_GREATER; |
575 | |
576 | out_free: |
577 | kfree(dent); |
578 | return err; |
579 | } |
580 | |
581 | /** |
582 | * get_znode - get a TNC znode that may not be loaded yet. |
583 | * @c: UBIFS file-system description object |
584 | * @znode: parent znode |
585 | * @n: znode branch slot number |
586 | * |
587 | * This function returns the znode or a negative error code. |
588 | */ |
589 | static struct ubifs_znode *get_znode(struct ubifs_info *c, |
590 | struct ubifs_znode *znode, int n) |
591 | { |
592 | struct ubifs_zbranch *zbr; |
593 | |
594 | zbr = &znode->zbranch[n]; |
595 | if (zbr->znode) |
596 | znode = zbr->znode; |
597 | else |
598 | znode = ubifs_load_znode(c, zbr, znode, n); |
599 | return znode; |
600 | } |
601 | |
602 | /** |
603 | * tnc_next - find next TNC entry. |
604 | * @c: UBIFS file-system description object |
605 | * @zn: znode is passed and returned here |
606 | * @n: znode branch slot number is passed and returned here |
607 | * |
608 | * This function returns %0 if the next TNC entry is found, %-ENOENT if there is |
609 | * no next entry, or a negative error code otherwise. |
610 | */ |
611 | static int tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n) |
612 | { |
613 | struct ubifs_znode *znode = *zn; |
614 | int nn = *n; |
615 | |
616 | nn += 1; |
617 | if (nn < znode->child_cnt) { |
618 | *n = nn; |
619 | return 0; |
620 | } |
621 | while (1) { |
622 | struct ubifs_znode *zp; |
623 | |
624 | zp = znode->parent; |
625 | if (!zp) |
626 | return -ENOENT; |
627 | nn = znode->iip + 1; |
628 | znode = zp; |
629 | if (nn < znode->child_cnt) { |
630 | znode = get_znode(c, znode, nn); |
631 | if (IS_ERR(znode)) |
632 | return PTR_ERR(znode); |
633 | while (znode->level != 0) { |
634 | znode = get_znode(c, znode, 0); |
635 | if (IS_ERR(znode)) |
636 | return PTR_ERR(znode); |
637 | } |
638 | nn = 0; |
639 | break; |
640 | } |
641 | } |
642 | *zn = znode; |
643 | *n = nn; |
644 | return 0; |
645 | } |
646 | |
647 | /** |
648 | * tnc_prev - find previous TNC entry. |
649 | * @c: UBIFS file-system description object |
650 | * @zn: znode is returned here |
651 | * @n: znode branch slot number is passed and returned here |
652 | * |
653 | * This function returns %0 if the previous TNC entry is found, %-ENOENT if |
654 | * there is no next entry, or a negative error code otherwise. |
655 | */ |
656 | static int tnc_prev(struct ubifs_info *c, struct ubifs_znode **zn, int *n) |
657 | { |
658 | struct ubifs_znode *znode = *zn; |
659 | int nn = *n; |
660 | |
661 | if (nn > 0) { |
662 | *n = nn - 1; |
663 | return 0; |
664 | } |
665 | while (1) { |
666 | struct ubifs_znode *zp; |
667 | |
668 | zp = znode->parent; |
669 | if (!zp) |
670 | return -ENOENT; |
671 | nn = znode->iip - 1; |
672 | znode = zp; |
673 | if (nn >= 0) { |
674 | znode = get_znode(c, znode, nn); |
675 | if (IS_ERR(znode)) |
676 | return PTR_ERR(znode); |
677 | while (znode->level != 0) { |
678 | nn = znode->child_cnt - 1; |
679 | znode = get_znode(c, znode, nn); |
680 | if (IS_ERR(znode)) |
681 | return PTR_ERR(znode); |
682 | } |
683 | nn = znode->child_cnt - 1; |
684 | break; |
685 | } |
686 | } |
687 | *zn = znode; |
688 | *n = nn; |
689 | return 0; |
690 | } |
691 | |
692 | /** |
693 | * resolve_collision - resolve a collision. |
694 | * @c: UBIFS file-system description object |
695 | * @key: key of a directory or extended attribute entry |
696 | * @zn: znode is returned here |
697 | * @n: zbranch number is passed and returned here |
698 | * @nm: name of the entry |
699 | * |
700 | * This function is called for "hashed" keys to make sure that the found key |
701 | * really corresponds to the looked up node (directory or extended attribute |
702 | * entry). It returns %1 and sets @zn and @n if the collision is resolved. |
703 | * %0 is returned if @nm is not found and @zn and @n are set to the previous |
704 | * entry, i.e. to the entry after which @nm could follow if it were in TNC. |
705 | * This means that @n may be set to %-1 if the leftmost key in @zn is the |
706 | * previous one. A negative error code is returned on failures. |
707 | */ |
708 | static int resolve_collision(struct ubifs_info *c, const union ubifs_key *key, |
709 | struct ubifs_znode **zn, int *n, |
710 | const struct qstr *nm) |
711 | { |
712 | int err; |
713 | |
714 | err = matches_name(c, &(*zn)->zbranch[*n], nm); |
715 | if (unlikely(err < 0)) |
716 | return err; |
717 | if (err == NAME_MATCHES) |
718 | return 1; |
719 | |
720 | if (err == NAME_GREATER) { |
721 | /* Look left */ |
722 | while (1) { |
723 | err = tnc_prev(c, zn, n); |
724 | if (err == -ENOENT) { |
725 | ubifs_assert(*n == 0); |
726 | *n = -1; |
727 | return 0; |
728 | } |
729 | if (err < 0) |
730 | return err; |
731 | if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) { |
732 | /* |
733 | * We have found the branch after which we would |
734 | * like to insert, but inserting in this znode |
735 | * may still be wrong. Consider the following 3 |
736 | * znodes, in the case where we are resolving a |
737 | * collision with Key2. |
738 | * |
739 | * znode zp |
740 | * ---------------------- |
741 | * level 1 | Key0 | Key1 | |
742 | * ----------------------- |
743 | * | | |
744 | * znode za | | znode zb |
745 | * ------------ ------------ |
746 | * level 0 | Key0 | | Key2 | |
747 | * ------------ ------------ |
748 | * |
749 | * The lookup finds Key2 in znode zb. Lets say |
750 | * there is no match and the name is greater so |
751 | * we look left. When we find Key0, we end up |
752 | * here. If we return now, we will insert into |
753 | * znode za at slot n = 1. But that is invalid |
754 | * according to the parent's keys. Key2 must |
755 | * be inserted into znode zb. |
756 | * |
757 | * Note, this problem is not relevant for the |
758 | * case when we go right, because |
759 | * 'tnc_insert()' would correct the parent key. |
760 | */ |
761 | if (*n == (*zn)->child_cnt - 1) { |
762 | err = tnc_next(c, zn, n); |
763 | if (err) { |
764 | /* Should be impossible */ |
765 | ubifs_assert(0); |
766 | if (err == -ENOENT) |
767 | err = -EINVAL; |
768 | return err; |
769 | } |
770 | ubifs_assert(*n == 0); |
771 | *n = -1; |
772 | } |
773 | return 0; |
774 | } |
775 | err = matches_name(c, &(*zn)->zbranch[*n], nm); |
776 | if (err < 0) |
777 | return err; |
778 | if (err == NAME_LESS) |
779 | return 0; |
780 | if (err == NAME_MATCHES) |
781 | return 1; |
782 | ubifs_assert(err == NAME_GREATER); |
783 | } |
784 | } else { |
785 | int nn = *n; |
786 | struct ubifs_znode *znode = *zn; |
787 | |
788 | /* Look right */ |
789 | while (1) { |
790 | err = tnc_next(c, &znode, &nn); |
791 | if (err == -ENOENT) |
792 | return 0; |
793 | if (err < 0) |
794 | return err; |
795 | if (keys_cmp(c, &znode->zbranch[nn].key, key)) |
796 | return 0; |
797 | err = matches_name(c, &znode->zbranch[nn], nm); |
798 | if (err < 0) |
799 | return err; |
800 | if (err == NAME_GREATER) |
801 | return 0; |
802 | *zn = znode; |
803 | *n = nn; |
804 | if (err == NAME_MATCHES) |
805 | return 1; |
806 | ubifs_assert(err == NAME_LESS); |
807 | } |
808 | } |
809 | } |
810 | |
811 | /** |
812 | * fallible_matches_name - determine if a dent matches a given name. |
813 | * @c: UBIFS file-system description object |
814 | * @zbr: zbranch of dent |
815 | * @nm: name to match |
816 | * |
817 | * This is a "fallible" version of 'matches_name()' function which does not |
818 | * panic if the direntry/xentry referred by @zbr does not exist on the media. |
819 | * |
820 | * This function checks if xentry/direntry referred by zbranch @zbr matches name |
821 | * @nm. Returns %NAME_MATCHES it does, %NAME_LESS if the name referred by @zbr |
822 | * is less than @nm, %NAME_GREATER if it is greater than @nm, and @NOT_ON_MEDIA |
823 | * if xentry/direntry referred by @zbr does not exist on the media. A negative |
824 | * error code is returned in case of failure. |
825 | */ |
826 | static int fallible_matches_name(struct ubifs_info *c, |
827 | struct ubifs_zbranch *zbr, |
828 | const struct qstr *nm) |
829 | { |
830 | struct ubifs_dent_node *dent; |
831 | int nlen, err; |
832 | |
833 | /* If possible, match against the dent in the leaf node cache */ |
834 | if (!zbr->leaf) { |
835 | dent = kmalloc(zbr->len, GFP_NOFS); |
836 | if (!dent) |
837 | return -ENOMEM; |
838 | |
839 | err = fallible_read_node(c, &zbr->key, zbr, dent); |
840 | if (err < 0) |
841 | goto out_free; |
842 | if (err == 0) { |
843 | /* The node was not present */ |
844 | err = NOT_ON_MEDIA; |
845 | goto out_free; |
846 | } |
847 | ubifs_assert(err == 1); |
848 | |
849 | err = lnc_add_directly(c, zbr, dent); |
850 | if (err) |
851 | goto out_free; |
852 | } else |
853 | dent = zbr->leaf; |
854 | |
855 | nlen = le16_to_cpu(dent->nlen); |
856 | err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len)); |
857 | if (err == 0) { |
858 | if (nlen == nm->len) |
859 | return NAME_MATCHES; |
860 | else if (nlen < nm->len) |
861 | return NAME_LESS; |
862 | else |
863 | return NAME_GREATER; |
864 | } else if (err < 0) |
865 | return NAME_LESS; |
866 | else |
867 | return NAME_GREATER; |
868 | |
869 | out_free: |
870 | kfree(dent); |
871 | return err; |
872 | } |
873 | |
874 | /** |
875 | * fallible_resolve_collision - resolve a collision even if nodes are missing. |
876 | * @c: UBIFS file-system description object |
877 | * @key: key |
878 | * @zn: znode is returned here |
879 | * @n: branch number is passed and returned here |
880 | * @nm: name of directory entry |
881 | * @adding: indicates caller is adding a key to the TNC |
882 | * |
883 | * This is a "fallible" version of the 'resolve_collision()' function which |
884 | * does not panic if one of the nodes referred to by TNC does not exist on the |
885 | * media. This may happen when replaying the journal if a deleted node was |
886 | * Garbage-collected and the commit was not done. A branch that refers to a node |
887 | * that is not present is called a dangling branch. The following are the return |
888 | * codes for this function: |
889 | * o if @nm was found, %1 is returned and @zn and @n are set to the found |
890 | * branch; |
891 | * o if we are @adding and @nm was not found, %0 is returned; |
892 | * o if we are not @adding and @nm was not found, but a dangling branch was |
893 | * found, then %1 is returned and @zn and @n are set to the dangling branch; |
894 | * o a negative error code is returned in case of failure. |
895 | */ |
896 | static int fallible_resolve_collision(struct ubifs_info *c, |
897 | const union ubifs_key *key, |
898 | struct ubifs_znode **zn, int *n, |
899 | const struct qstr *nm, int adding) |
900 | { |
901 | struct ubifs_znode *o_znode = NULL, *znode = *zn; |
902 | int uninitialized_var(o_n), err, cmp, unsure = 0, nn = *n; |
903 | |
904 | cmp = fallible_matches_name(c, &znode->zbranch[nn], nm); |
905 | if (unlikely(cmp < 0)) |
906 | return cmp; |
907 | if (cmp == NAME_MATCHES) |
908 | return 1; |
909 | if (cmp == NOT_ON_MEDIA) { |
910 | o_znode = znode; |
911 | o_n = nn; |
912 | /* |
913 | * We are unlucky and hit a dangling branch straight away. |
914 | * Now we do not really know where to go to find the needed |
915 | * branch - to the left or to the right. Well, let's try left. |
916 | */ |
917 | unsure = 1; |
918 | } else if (!adding) |
919 | unsure = 1; /* Remove a dangling branch wherever it is */ |
920 | |
921 | if (cmp == NAME_GREATER || unsure) { |
922 | /* Look left */ |
923 | while (1) { |
924 | err = tnc_prev(c, zn, n); |
925 | if (err == -ENOENT) { |
926 | ubifs_assert(*n == 0); |
927 | *n = -1; |
928 | break; |
929 | } |
930 | if (err < 0) |
931 | return err; |
932 | if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) { |
933 | /* See comments in 'resolve_collision()' */ |
934 | if (*n == (*zn)->child_cnt - 1) { |
935 | err = tnc_next(c, zn, n); |
936 | if (err) { |
937 | /* Should be impossible */ |
938 | ubifs_assert(0); |
939 | if (err == -ENOENT) |
940 | err = -EINVAL; |
941 | return err; |
942 | } |
943 | ubifs_assert(*n == 0); |
944 | *n = -1; |
945 | } |
946 | break; |
947 | } |
948 | err = fallible_matches_name(c, &(*zn)->zbranch[*n], nm); |
949 | if (err < 0) |
950 | return err; |
951 | if (err == NAME_MATCHES) |
952 | return 1; |
953 | if (err == NOT_ON_MEDIA) { |
954 | o_znode = *zn; |
955 | o_n = *n; |
956 | continue; |
957 | } |
958 | if (!adding) |
959 | continue; |
960 | if (err == NAME_LESS) |
961 | break; |
962 | else |
963 | unsure = 0; |
964 | } |
965 | } |
966 | |
967 | if (cmp == NAME_LESS || unsure) { |
968 | /* Look right */ |
969 | *zn = znode; |
970 | *n = nn; |
971 | while (1) { |
972 | err = tnc_next(c, &znode, &nn); |
973 | if (err == -ENOENT) |
974 | break; |
975 | if (err < 0) |
976 | return err; |
977 | if (keys_cmp(c, &znode->zbranch[nn].key, key)) |
978 | break; |
979 | err = fallible_matches_name(c, &znode->zbranch[nn], nm); |
980 | if (err < 0) |
981 | return err; |
982 | if (err == NAME_GREATER) |
983 | break; |
984 | *zn = znode; |
985 | *n = nn; |
986 | if (err == NAME_MATCHES) |
987 | return 1; |
988 | if (err == NOT_ON_MEDIA) { |
989 | o_znode = znode; |
990 | o_n = nn; |
991 | } |
992 | } |
993 | } |
994 | |
995 | /* Never match a dangling branch when adding */ |
996 | if (adding || !o_znode) |
997 | return 0; |
998 | |
999 | dbg_mnt("dangling match LEB %d:%d len %d %s", |
1000 | o_znode->zbranch[o_n].lnum, o_znode->zbranch[o_n].offs, |
1001 | o_znode->zbranch[o_n].len, DBGKEY(key)); |
1002 | *zn = o_znode; |
1003 | *n = o_n; |
1004 | return 1; |
1005 | } |
1006 | |
1007 | /** |
1008 | * matches_position - determine if a zbranch matches a given position. |
1009 | * @zbr: zbranch of dent |
1010 | * @lnum: LEB number of dent to match |
1011 | * @offs: offset of dent to match |
1012 | * |
1013 | * This function returns %1 if @lnum:@offs matches, and %0 otherwise. |
1014 | */ |
1015 | static int matches_position(struct ubifs_zbranch *zbr, int lnum, int offs) |
1016 | { |
1017 | if (zbr->lnum == lnum && zbr->offs == offs) |
1018 | return 1; |
1019 | else |
1020 | return 0; |
1021 | } |
1022 | |
1023 | /** |
1024 | * resolve_collision_directly - resolve a collision directly. |
1025 | * @c: UBIFS file-system description object |
1026 | * @key: key of directory entry |
1027 | * @zn: znode is passed and returned here |
1028 | * @n: zbranch number is passed and returned here |
1029 | * @lnum: LEB number of dent node to match |
1030 | * @offs: offset of dent node to match |
1031 | * |
1032 | * This function is used for "hashed" keys to make sure the found directory or |
1033 | * extended attribute entry node is what was looked for. It is used when the |
1034 | * flash address of the right node is known (@lnum:@offs) which makes it much |
1035 | * easier to resolve collisions (no need to read entries and match full |
1036 | * names). This function returns %1 and sets @zn and @n if the collision is |
1037 | * resolved, %0 if @lnum:@offs is not found and @zn and @n are set to the |
1038 | * previous directory entry. Otherwise a negative error code is returned. |
1039 | */ |
1040 | static int resolve_collision_directly(struct ubifs_info *c, |
1041 | const union ubifs_key *key, |
1042 | struct ubifs_znode **zn, int *n, |
1043 | int lnum, int offs) |
1044 | { |
1045 | struct ubifs_znode *znode; |
1046 | int nn, err; |
1047 | |
1048 | znode = *zn; |
1049 | nn = *n; |
1050 | if (matches_position(&znode->zbranch[nn], lnum, offs)) |
1051 | return 1; |
1052 | |
1053 | /* Look left */ |
1054 | while (1) { |
1055 | err = tnc_prev(c, &znode, &nn); |
1056 | if (err == -ENOENT) |
1057 | break; |
1058 | if (err < 0) |
1059 | return err; |
1060 | if (keys_cmp(c, &znode->zbranch[nn].key, key)) |
1061 | break; |
1062 | if (matches_position(&znode->zbranch[nn], lnum, offs)) { |
1063 | *zn = znode; |
1064 | *n = nn; |
1065 | return 1; |
1066 | } |
1067 | } |
1068 | |
1069 | /* Look right */ |
1070 | znode = *zn; |
1071 | nn = *n; |
1072 | while (1) { |
1073 | err = tnc_next(c, &znode, &nn); |
1074 | if (err == -ENOENT) |
1075 | return 0; |
1076 | if (err < 0) |
1077 | return err; |
1078 | if (keys_cmp(c, &znode->zbranch[nn].key, key)) |
1079 | return 0; |
1080 | *zn = znode; |
1081 | *n = nn; |
1082 | if (matches_position(&znode->zbranch[nn], lnum, offs)) |
1083 | return 1; |
1084 | } |
1085 | } |
1086 | |
1087 | /** |
1088 | * dirty_cow_bottom_up - dirty a znode and its ancestors. |
1089 | * @c: UBIFS file-system description object |
1090 | * @znode: znode to dirty |
1091 | * |
1092 | * If we do not have a unique key that resides in a znode, then we cannot |
1093 | * dirty that znode from the top down (i.e. by using lookup_level0_dirty) |
1094 | * This function records the path back to the last dirty ancestor, and then |
1095 | * dirties the znodes on that path. |
1096 | */ |
1097 | static struct ubifs_znode *dirty_cow_bottom_up(struct ubifs_info *c, |
1098 | struct ubifs_znode *znode) |
1099 | { |
1100 | struct ubifs_znode *zp; |
1101 | int *path = c->bottom_up_buf, p = 0; |
1102 | |
1103 | ubifs_assert(c->zroot.znode); |
1104 | ubifs_assert(znode); |
1105 | if (c->zroot.znode->level > BOTTOM_UP_HEIGHT) { |
1106 | kfree(c->bottom_up_buf); |
1107 | c->bottom_up_buf = kmalloc(c->zroot.znode->level * sizeof(int), |
1108 | GFP_NOFS); |
1109 | if (!c->bottom_up_buf) |
1110 | return ERR_PTR(-ENOMEM); |
1111 | path = c->bottom_up_buf; |
1112 | } |
1113 | if (c->zroot.znode->level) { |
1114 | /* Go up until parent is dirty */ |
1115 | while (1) { |
1116 | int n; |
1117 | |
1118 | zp = znode->parent; |
1119 | if (!zp) |
1120 | break; |
1121 | n = znode->iip; |
1122 | ubifs_assert(p < c->zroot.znode->level); |
1123 | path[p++] = n; |
1124 | if (!zp->cnext && ubifs_zn_dirty(znode)) |
1125 | break; |
1126 | znode = zp; |
1127 | } |
1128 | } |
1129 | |
1130 | /* Come back down, dirtying as we go */ |
1131 | while (1) { |
1132 | struct ubifs_zbranch *zbr; |
1133 | |
1134 | zp = znode->parent; |
1135 | if (zp) { |
1136 | ubifs_assert(path[p - 1] >= 0); |
1137 | ubifs_assert(path[p - 1] < zp->child_cnt); |
1138 | zbr = &zp->zbranch[path[--p]]; |
1139 | znode = dirty_cow_znode(c, zbr); |
1140 | } else { |
1141 | ubifs_assert(znode == c->zroot.znode); |
1142 | znode = dirty_cow_znode(c, &c->zroot); |
1143 | } |
1144 | if (IS_ERR(znode) || !p) |
1145 | break; |
1146 | ubifs_assert(path[p - 1] >= 0); |
1147 | ubifs_assert(path[p - 1] < znode->child_cnt); |
1148 | znode = znode->zbranch[path[p - 1]].znode; |
1149 | } |
1150 | |
1151 | return znode; |
1152 | } |
1153 | |
1154 | /** |
1155 | * ubifs_lookup_level0 - search for zero-level znode. |
1156 | * @c: UBIFS file-system description object |
1157 | * @key: key to lookup |
1158 | * @zn: znode is returned here |
1159 | * @n: znode branch slot number is returned here |
1160 | * |
1161 | * This function looks up the TNC tree and search for zero-level znode which |
1162 | * refers key @key. The found zero-level znode is returned in @zn. There are 3 |
1163 | * cases: |
1164 | * o exact match, i.e. the found zero-level znode contains key @key, then %1 |
1165 | * is returned and slot number of the matched branch is stored in @n; |
1166 | * o not exact match, which means that zero-level znode does not contain |
1167 | * @key, then %0 is returned and slot number of the closest branch is stored |
1168 | * in @n; |
1169 | * o @key is so small that it is even less than the lowest key of the |
1170 | * leftmost zero-level node, then %0 is returned and %0 is stored in @n. |
1171 | * |
1172 | * Note, when the TNC tree is traversed, some znodes may be absent, then this |
1173 | * function reads corresponding indexing nodes and inserts them to TNC. In |
1174 | * case of failure, a negative error code is returned. |
1175 | */ |
1176 | int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key, |
1177 | struct ubifs_znode **zn, int *n) |
1178 | { |
1179 | int err, exact; |
1180 | struct ubifs_znode *znode; |
1181 | unsigned long time = get_seconds(); |
1182 | |
1183 | dbg_tnc("search key %s", DBGKEY(key)); |
1184 | ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY); |
1185 | |
1186 | znode = c->zroot.znode; |
1187 | if (unlikely(!znode)) { |
1188 | znode = ubifs_load_znode(c, &c->zroot, NULL, 0); |
1189 | if (IS_ERR(znode)) |
1190 | return PTR_ERR(znode); |
1191 | } |
1192 | |
1193 | znode->time = time; |
1194 | |
1195 | while (1) { |
1196 | struct ubifs_zbranch *zbr; |
1197 | |
1198 | exact = ubifs_search_zbranch(c, znode, key, n); |
1199 | |
1200 | if (znode->level == 0) |
1201 | break; |
1202 | |
1203 | if (*n < 0) |
1204 | *n = 0; |
1205 | zbr = &znode->zbranch[*n]; |
1206 | |
1207 | if (zbr->znode) { |
1208 | znode->time = time; |
1209 | znode = zbr->znode; |
1210 | continue; |
1211 | } |
1212 | |
1213 | /* znode is not in TNC cache, load it from the media */ |
1214 | znode = ubifs_load_znode(c, zbr, znode, *n); |
1215 | if (IS_ERR(znode)) |
1216 | return PTR_ERR(znode); |
1217 | } |
1218 | |
1219 | *zn = znode; |
1220 | if (exact || !is_hash_key(c, key) || *n != -1) { |
1221 | dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n); |
1222 | return exact; |
1223 | } |
1224 | |
1225 | /* |
1226 | * Here is a tricky place. We have not found the key and this is a |
1227 | * "hashed" key, which may collide. The rest of the code deals with |
1228 | * situations like this: |
1229 | * |
1230 | * | 3 | 5 | |
1231 | * / \ |
1232 | * | 3 | 5 | | 6 | 7 | (x) |
1233 | * |
1234 | * Or more a complex example: |
1235 | * |
1236 | * | 1 | 5 | |
1237 | * / \ |
1238 | * | 1 | 3 | | 5 | 8 | |
1239 | * \ / |
1240 | * | 5 | 5 | | 6 | 7 | (x) |
1241 | * |
1242 | * In the examples, if we are looking for key "5", we may reach nodes |
1243 | * marked with "(x)". In this case what we have do is to look at the |
1244 | * left and see if there is "5" key there. If there is, we have to |
1245 | * return it. |
1246 | * |
1247 | * Note, this whole situation is possible because we allow to have |
1248 | * elements which are equivalent to the next key in the parent in the |
1249 | * children of current znode. For example, this happens if we split a |
1250 | * znode like this: | 3 | 5 | 5 | 6 | 7 |, which results in something |
1251 | * like this: |
1252 | * | 3 | 5 | |
1253 | * / \ |
1254 | * | 3 | 5 | | 5 | 6 | 7 | |
1255 | * ^ |
1256 | * And this becomes what is at the first "picture" after key "5" marked |
1257 | * with "^" is removed. What could be done is we could prohibit |
1258 | * splitting in the middle of the colliding sequence. Also, when |
1259 | * removing the leftmost key, we would have to correct the key of the |
1260 | * parent node, which would introduce additional complications. Namely, |
1261 | * if we changed the leftmost key of the parent znode, the garbage |
1262 | * collector would be unable to find it (GC is doing this when GC'ing |
1263 | * indexing LEBs). Although we already have an additional RB-tree where |
1264 | * we save such changed znodes (see 'ins_clr_old_idx_znode()') until |
1265 | * after the commit. But anyway, this does not look easy to implement |
1266 | * so we did not try this. |
1267 | */ |
1268 | err = tnc_prev(c, &znode, n); |
1269 | if (err == -ENOENT) { |
1270 | dbg_tnc("found 0, lvl %d, n -1", znode->level); |
1271 | *n = -1; |
1272 | return 0; |
1273 | } |
1274 | if (unlikely(err < 0)) |
1275 | return err; |
1276 | if (keys_cmp(c, key, &znode->zbranch[*n].key)) { |
1277 | dbg_tnc("found 0, lvl %d, n -1", znode->level); |
1278 | *n = -1; |
1279 | return 0; |
1280 | } |
1281 | |
1282 | dbg_tnc("found 1, lvl %d, n %d", znode->level, *n); |
1283 | *zn = znode; |
1284 | return 1; |
1285 | } |
1286 | |
1287 | /** |
1288 | * lookup_level0_dirty - search for zero-level znode dirtying. |
1289 | * @c: UBIFS file-system description object |
1290 | * @key: key to lookup |
1291 | * @zn: znode is returned here |
1292 | * @n: znode branch slot number is returned here |
1293 | * |
1294 | * This function looks up the TNC tree and search for zero-level znode which |
1295 | * refers key @key. The found zero-level znode is returned in @zn. There are 3 |
1296 | * cases: |
1297 | * o exact match, i.e. the found zero-level znode contains key @key, then %1 |
1298 | * is returned and slot number of the matched branch is stored in @n; |
1299 | * o not exact match, which means that zero-level znode does not contain @key |
1300 | * then %0 is returned and slot number of the closed branch is stored in |
1301 | * @n; |
1302 | * o @key is so small that it is even less than the lowest key of the |
1303 | * leftmost zero-level node, then %0 is returned and %-1 is stored in @n. |
1304 | * |
1305 | * Additionally all znodes in the path from the root to the located zero-level |
1306 | * znode are marked as dirty. |
1307 | * |
1308 | * Note, when the TNC tree is traversed, some znodes may be absent, then this |
1309 | * function reads corresponding indexing nodes and inserts them to TNC. In |
1310 | * case of failure, a negative error code is returned. |
1311 | */ |
1312 | static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key, |
1313 | struct ubifs_znode **zn, int *n) |
1314 | { |
1315 | int err, exact; |
1316 | struct ubifs_znode *znode; |
1317 | unsigned long time = get_seconds(); |
1318 | |
1319 | dbg_tnc("search and dirty key %s", DBGKEY(key)); |
1320 | |
1321 | znode = c->zroot.znode; |
1322 | if (unlikely(!znode)) { |
1323 | znode = ubifs_load_znode(c, &c->zroot, NULL, 0); |
1324 | if (IS_ERR(znode)) |
1325 | return PTR_ERR(znode); |
1326 | } |
1327 | |
1328 | znode = dirty_cow_znode(c, &c->zroot); |
1329 | if (IS_ERR(znode)) |
1330 | return PTR_ERR(znode); |
1331 | |
1332 | znode->time = time; |
1333 | |
1334 | while (1) { |
1335 | struct ubifs_zbranch *zbr; |
1336 | |
1337 | exact = ubifs_search_zbranch(c, znode, key, n); |
1338 | |
1339 | if (znode->level == 0) |
1340 | break; |
1341 | |
1342 | if (*n < 0) |
1343 | *n = 0; |
1344 | zbr = &znode->zbranch[*n]; |
1345 | |
1346 | if (zbr->znode) { |
1347 | znode->time = time; |
1348 | znode = dirty_cow_znode(c, zbr); |
1349 | if (IS_ERR(znode)) |
1350 | return PTR_ERR(znode); |
1351 | continue; |
1352 | } |
1353 | |
1354 | /* znode is not in TNC cache, load it from the media */ |
1355 | znode = ubifs_load_znode(c, zbr, znode, *n); |
1356 | if (IS_ERR(znode)) |
1357 | return PTR_ERR(znode); |
1358 | znode = dirty_cow_znode(c, zbr); |
1359 | if (IS_ERR(znode)) |
1360 | return PTR_ERR(znode); |
1361 | } |
1362 | |
1363 | *zn = znode; |
1364 | if (exact || !is_hash_key(c, key) || *n != -1) { |
1365 | dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n); |
1366 | return exact; |
1367 | } |
1368 | |
1369 | /* |
1370 | * See huge comment at 'lookup_level0_dirty()' what is the rest of the |
1371 | * code. |
1372 | */ |
1373 | err = tnc_prev(c, &znode, n); |
1374 | if (err == -ENOENT) { |
1375 | *n = -1; |
1376 | dbg_tnc("found 0, lvl %d, n -1", znode->level); |
1377 | return 0; |
1378 | } |
1379 | if (unlikely(err < 0)) |
1380 | return err; |
1381 | if (keys_cmp(c, key, &znode->zbranch[*n].key)) { |
1382 | *n = -1; |
1383 | dbg_tnc("found 0, lvl %d, n -1", znode->level); |
1384 | return 0; |
1385 | } |
1386 | |
1387 | if (znode->cnext || !ubifs_zn_dirty(znode)) { |
1388 | znode = dirty_cow_bottom_up(c, znode); |
1389 | if (IS_ERR(znode)) |
1390 | return PTR_ERR(znode); |
1391 | } |
1392 | |
1393 | dbg_tnc("found 1, lvl %d, n %d", znode->level, *n); |
1394 | *zn = znode; |
1395 | return 1; |
1396 | } |
1397 | |
1398 | /** |
1399 | * maybe_leb_gced - determine if a LEB may have been garbage collected. |
1400 | * @c: UBIFS file-system description object |
1401 | * @lnum: LEB number |
1402 | * @gc_seq1: garbage collection sequence number |
1403 | * |
1404 | * This function determines if @lnum may have been garbage collected since |
1405 | * sequence number @gc_seq1. If it may have been then %1 is returned, otherwise |
1406 | * %0 is returned. |
1407 | */ |
1408 | static int maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1) |
1409 | { |
1410 | int gc_seq2, gced_lnum; |
1411 | |
1412 | gced_lnum = c->gced_lnum; |
1413 | smp_rmb(); |
1414 | gc_seq2 = c->gc_seq; |
1415 | /* Same seq means no GC */ |
1416 | if (gc_seq1 == gc_seq2) |
1417 | return 0; |
1418 | /* Different by more than 1 means we don't know */ |
1419 | if (gc_seq1 + 1 != gc_seq2) |
1420 | return 1; |
1421 | /* |
1422 | * We have seen the sequence number has increased by 1. Now we need to |
1423 | * be sure we read the right LEB number, so read it again. |
1424 | */ |
1425 | smp_rmb(); |
1426 | if (gced_lnum != c->gced_lnum) |
1427 | return 1; |
1428 | /* Finally we can check lnum */ |
1429 | if (gced_lnum == lnum) |
1430 | return 1; |
1431 | return 0; |
1432 | } |
1433 | |
1434 | /** |
1435 | * ubifs_tnc_locate - look up a file-system node and return it and its location. |
1436 | * @c: UBIFS file-system description object |
1437 | * @key: node key to lookup |
1438 | * @node: the node is returned here |
1439 | * @lnum: LEB number is returned here |
1440 | * @offs: offset is returned here |
1441 | * |
1442 | * This function looks up and reads node with key @key. The caller has to make |
1443 | * sure the @node buffer is large enough to fit the node. Returns zero in case |
1444 | * of success, %-ENOENT if the node was not found, and a negative error code in |
1445 | * case of failure. The node location can be returned in @lnum and @offs. |
1446 | */ |
1447 | int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key, |
1448 | void *node, int *lnum, int *offs) |
1449 | { |
1450 | int found, n, err, safely = 0, gc_seq1; |
1451 | struct ubifs_znode *znode; |
1452 | struct ubifs_zbranch zbr, *zt; |
1453 | |
1454 | again: |
1455 | mutex_lock(&c->tnc_mutex); |
1456 | found = ubifs_lookup_level0(c, key, &znode, &n); |
1457 | if (!found) { |
1458 | err = -ENOENT; |
1459 | goto out; |
1460 | } else if (found < 0) { |
1461 | err = found; |
1462 | goto out; |
1463 | } |
1464 | zt = &znode->zbranch[n]; |
1465 | if (lnum) { |
1466 | *lnum = zt->lnum; |
1467 | *offs = zt->offs; |
1468 | } |
1469 | if (is_hash_key(c, key)) { |
1470 | /* |
1471 | * In this case the leaf node cache gets used, so we pass the |
1472 | * address of the zbranch and keep the mutex locked |
1473 | */ |
1474 | err = tnc_read_node_nm(c, zt, node); |
1475 | goto out; |
1476 | } |
1477 | if (safely) { |
1478 | err = ubifs_tnc_read_node(c, zt, node); |
1479 | goto out; |
1480 | } |
1481 | /* Drop the TNC mutex prematurely and race with garbage collection */ |
1482 | zbr = znode->zbranch[n]; |
1483 | gc_seq1 = c->gc_seq; |
1484 | mutex_unlock(&c->tnc_mutex); |
1485 | |
1486 | if (ubifs_get_wbuf(c, zbr.lnum)) { |
1487 | /* We do not GC journal heads */ |
1488 | err = ubifs_tnc_read_node(c, &zbr, node); |
1489 | return err; |
1490 | } |
1491 | |
1492 | err = fallible_read_node(c, key, &zbr, node); |
1493 | if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) { |
1494 | /* |
1495 | * The node may have been GC'ed out from under us so try again |
1496 | * while keeping the TNC mutex locked. |
1497 | */ |
1498 | safely = 1; |
1499 | goto again; |
1500 | } |
1501 | return 0; |
1502 | |
1503 | out: |
1504 | mutex_unlock(&c->tnc_mutex); |
1505 | return err; |
1506 | } |
1507 | |
1508 | /** |
1509 | * ubifs_tnc_get_bu_keys - lookup keys for bulk-read. |
1510 | * @c: UBIFS file-system description object |
1511 | * @bu: bulk-read parameters and results |
1512 | * |
1513 | * Lookup consecutive data node keys for the same inode that reside |
1514 | * consecutively in the same LEB. This function returns zero in case of success |
1515 | * and a negative error code in case of failure. |
1516 | * |
1517 | * Note, if the bulk-read buffer length (@bu->buf_len) is known, this function |
1518 | * makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares |
1519 | * maximum possible amount of nodes for bulk-read. |
1520 | */ |
1521 | int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu) |
1522 | { |
1523 | int n, err = 0, lnum = -1, uninitialized_var(offs); |
1524 | int uninitialized_var(len); |
1525 | unsigned int block = key_block(c, &bu->key); |
1526 | struct ubifs_znode *znode; |
1527 | |
1528 | bu->cnt = 0; |
1529 | bu->blk_cnt = 0; |
1530 | bu->eof = 0; |
1531 | |
1532 | mutex_lock(&c->tnc_mutex); |
1533 | /* Find first key */ |
1534 | err = ubifs_lookup_level0(c, &bu->key, &znode, &n); |
1535 | if (err < 0) |
1536 | goto out; |
1537 | if (err) { |
1538 | /* Key found */ |
1539 | len = znode->zbranch[n].len; |
1540 | /* The buffer must be big enough for at least 1 node */ |
1541 | if (len > bu->buf_len) { |
1542 | err = -EINVAL; |
1543 | goto out; |
1544 | } |
1545 | /* Add this key */ |
1546 | bu->zbranch[bu->cnt++] = znode->zbranch[n]; |
1547 | bu->blk_cnt += 1; |
1548 | lnum = znode->zbranch[n].lnum; |
1549 | offs = ALIGN(znode->zbranch[n].offs + len, 8); |
1550 | } |
1551 | while (1) { |
1552 | struct ubifs_zbranch *zbr; |
1553 | union ubifs_key *key; |
1554 | unsigned int next_block; |
1555 | |
1556 | /* Find next key */ |
1557 | err = tnc_next(c, &znode, &n); |
1558 | if (err) |
1559 | goto out; |
1560 | zbr = &znode->zbranch[n]; |
1561 | key = &zbr->key; |
1562 | /* See if there is another data key for this file */ |
1563 | if (key_inum(c, key) != key_inum(c, &bu->key) || |
1564 | key_type(c, key) != UBIFS_DATA_KEY) { |
1565 | err = -ENOENT; |
1566 | goto out; |
1567 | } |
1568 | if (lnum < 0) { |
1569 | /* First key found */ |
1570 | lnum = zbr->lnum; |
1571 | offs = ALIGN(zbr->offs + zbr->len, 8); |
1572 | len = zbr->len; |
1573 | if (len > bu->buf_len) { |
1574 | err = -EINVAL; |
1575 | goto out; |
1576 | } |
1577 | } else { |
1578 | /* |
1579 | * The data nodes must be in consecutive positions in |
1580 | * the same LEB. |
1581 | */ |
1582 | if (zbr->lnum != lnum || zbr->offs != offs) |
1583 | goto out; |
1584 | offs += ALIGN(zbr->len, 8); |
1585 | len = ALIGN(len, 8) + zbr->len; |
1586 | /* Must not exceed buffer length */ |
1587 | if (len > bu->buf_len) |
1588 | goto out; |
1589 | } |
1590 | /* Allow for holes */ |
1591 | next_block = key_block(c, key); |
1592 | bu->blk_cnt += (next_block - block - 1); |
1593 | if (bu->blk_cnt >= UBIFS_MAX_BULK_READ) |
1594 | goto out; |
1595 | block = next_block; |
1596 | /* Add this key */ |
1597 | bu->zbranch[bu->cnt++] = *zbr; |
1598 | bu->blk_cnt += 1; |
1599 | /* See if we have room for more */ |
1600 | if (bu->cnt >= UBIFS_MAX_BULK_READ) |
1601 | goto out; |
1602 | if (bu->blk_cnt >= UBIFS_MAX_BULK_READ) |
1603 | goto out; |
1604 | } |
1605 | out: |
1606 | if (err == -ENOENT) { |
1607 | bu->eof = 1; |
1608 | err = 0; |
1609 | } |
1610 | bu->gc_seq = c->gc_seq; |
1611 | mutex_unlock(&c->tnc_mutex); |
1612 | if (err) |
1613 | return err; |
1614 | /* |
1615 | * An enormous hole could cause bulk-read to encompass too many |
1616 | * page cache pages, so limit the number here. |
1617 | */ |
1618 | if (bu->blk_cnt > UBIFS_MAX_BULK_READ) |
1619 | bu->blk_cnt = UBIFS_MAX_BULK_READ; |
1620 | /* |
1621 | * Ensure that bulk-read covers a whole number of page cache |
1622 | * pages. |
1623 | */ |
1624 | if (UBIFS_BLOCKS_PER_PAGE == 1 || |
1625 | !(bu->blk_cnt & (UBIFS_BLOCKS_PER_PAGE - 1))) |
1626 | return 0; |
1627 | if (bu->eof) { |
1628 | /* At the end of file we can round up */ |
1629 | bu->blk_cnt += UBIFS_BLOCKS_PER_PAGE - 1; |
1630 | return 0; |
1631 | } |
1632 | /* Exclude data nodes that do not make up a whole page cache page */ |
1633 | block = key_block(c, &bu->key) + bu->blk_cnt; |
1634 | block &= ~(UBIFS_BLOCKS_PER_PAGE - 1); |
1635 | while (bu->cnt) { |
1636 | if (key_block(c, &bu->zbranch[bu->cnt - 1].key) < block) |
1637 | break; |
1638 | bu->cnt -= 1; |
1639 | } |
1640 | return 0; |
1641 | } |
1642 | |
1643 | /** |
1644 | * read_wbuf - bulk-read from a LEB with a wbuf. |
1645 | * @wbuf: wbuf that may overlap the read |
1646 | * @buf: buffer into which to read |
1647 | * @len: read length |
1648 | * @lnum: LEB number from which to read |
1649 | * @offs: offset from which to read |
1650 | * |
1651 | * This functions returns %0 on success or a negative error code on failure. |
1652 | */ |
1653 | static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum, |
1654 | int offs) |
1655 | { |
1656 | const struct ubifs_info *c = wbuf->c; |
1657 | int rlen, overlap; |
1658 | |
1659 | dbg_io("LEB %d:%d, length %d", lnum, offs, len); |
1660 | ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0); |
1661 | ubifs_assert(!(offs & 7) && offs < c->leb_size); |
1662 | ubifs_assert(offs + len <= c->leb_size); |
1663 | |
1664 | spin_lock(&wbuf->lock); |
1665 | overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs); |
1666 | if (!overlap) { |
1667 | /* We may safely unlock the write-buffer and read the data */ |
1668 | spin_unlock(&wbuf->lock); |
1669 | return ubi_read(c->ubi, lnum, buf, offs, len); |
1670 | } |
1671 | |
1672 | /* Don't read under wbuf */ |
1673 | rlen = wbuf->offs - offs; |
1674 | if (rlen < 0) |
1675 | rlen = 0; |
1676 | |
1677 | /* Copy the rest from the write-buffer */ |
1678 | memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen); |
1679 | spin_unlock(&wbuf->lock); |
1680 | |
1681 | if (rlen > 0) |
1682 | /* Read everything that goes before write-buffer */ |
1683 | return ubi_read(c->ubi, lnum, buf, offs, rlen); |
1684 | |
1685 | return 0; |
1686 | } |
1687 | |
1688 | /** |
1689 | * validate_data_node - validate data nodes for bulk-read. |
1690 | * @c: UBIFS file-system description object |
1691 | * @buf: buffer containing data node to validate |
1692 | * @zbr: zbranch of data node to validate |
1693 | * |
1694 | * This functions returns %0 on success or a negative error code on failure. |
1695 | */ |
1696 | static int validate_data_node(struct ubifs_info *c, void *buf, |
1697 | struct ubifs_zbranch *zbr) |
1698 | { |
1699 | union ubifs_key key1; |
1700 | struct ubifs_ch *ch = buf; |
1701 | int err, len; |
1702 | |
1703 | if (ch->node_type != UBIFS_DATA_NODE) { |
1704 | ubifs_err("bad node type (%d but expected %d)", |
1705 | ch->node_type, UBIFS_DATA_NODE); |
1706 | goto out_err; |
1707 | } |
1708 | |
1709 | err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0, 0); |
1710 | if (err) { |
1711 | ubifs_err("expected node type %d", UBIFS_DATA_NODE); |
1712 | goto out; |
1713 | } |
1714 | |
1715 | len = le32_to_cpu(ch->len); |
1716 | if (len != zbr->len) { |
1717 | ubifs_err("bad node length %d, expected %d", len, zbr->len); |
1718 | goto out_err; |
1719 | } |
1720 | |
1721 | /* Make sure the key of the read node is correct */ |
1722 | key_read(c, buf + UBIFS_KEY_OFFSET, &key1); |
1723 | if (!keys_eq(c, &zbr->key, &key1)) { |
1724 | ubifs_err("bad key in node at LEB %d:%d", |
1725 | zbr->lnum, zbr->offs); |
1726 | dbg_tnc("looked for key %s found node's key %s", |
1727 | DBGKEY(&zbr->key), DBGKEY1(&key1)); |
1728 | goto out_err; |
1729 | } |
1730 | |
1731 | return 0; |
1732 | |
1733 | out_err: |
1734 | err = -EINVAL; |
1735 | out: |
1736 | ubifs_err("bad node at LEB %d:%d", zbr->lnum, zbr->offs); |
1737 | dbg_dump_node(c, buf); |
1738 | dbg_dump_stack(); |
1739 | return err; |
1740 | } |
1741 | |
1742 | /** |
1743 | * ubifs_tnc_bulk_read - read a number of data nodes in one go. |
1744 | * @c: UBIFS file-system description object |
1745 | * @bu: bulk-read parameters and results |
1746 | * |
1747 | * This functions reads and validates the data nodes that were identified by the |
1748 | * 'ubifs_tnc_get_bu_keys()' function. This functions returns %0 on success, |
1749 | * -EAGAIN to indicate a race with GC, or another negative error code on |
1750 | * failure. |
1751 | */ |
1752 | int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu) |
1753 | { |
1754 | int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i; |
1755 | struct ubifs_wbuf *wbuf; |
1756 | void *buf; |
1757 | |
1758 | len = bu->zbranch[bu->cnt - 1].offs; |
1759 | len += bu->zbranch[bu->cnt - 1].len - offs; |
1760 | if (len > bu->buf_len) { |
1761 | ubifs_err("buffer too small %d vs %d", bu->buf_len, len); |
1762 | return -EINVAL; |
1763 | } |
1764 | |
1765 | /* Do the read */ |
1766 | wbuf = ubifs_get_wbuf(c, lnum); |
1767 | if (wbuf) |
1768 | err = read_wbuf(wbuf, bu->buf, len, lnum, offs); |
1769 | else |
1770 | err = ubi_read(c->ubi, lnum, bu->buf, offs, len); |
1771 | |
1772 | /* Check for a race with GC */ |
1773 | if (maybe_leb_gced(c, lnum, bu->gc_seq)) |
1774 | return -EAGAIN; |
1775 | |
1776 | if (err && err != -EBADMSG) { |
1777 | ubifs_err("failed to read from LEB %d:%d, error %d", |
1778 | lnum, offs, err); |
1779 | dbg_dump_stack(); |
1780 | dbg_tnc("key %s", DBGKEY(&bu->key)); |
1781 | return err; |
1782 | } |
1783 | |
1784 | /* Validate the nodes read */ |
1785 | buf = bu->buf; |
1786 | for (i = 0; i < bu->cnt; i++) { |
1787 | err = validate_data_node(c, buf, &bu->zbranch[i]); |
1788 | if (err) |
1789 | return err; |
1790 | buf = buf + ALIGN(bu->zbranch[i].len, 8); |
1791 | } |
1792 | |
1793 | return 0; |
1794 | } |
1795 | |
1796 | /** |
1797 | * do_lookup_nm- look up a "hashed" node. |
1798 | * @c: UBIFS file-system description object |
1799 | * @key: node key to lookup |
1800 | * @node: the node is returned here |
1801 | * @nm: node name |
1802 | * |
1803 | * This function look up and reads a node which contains name hash in the key. |
1804 | * Since the hash may have collisions, there may be many nodes with the same |
1805 | * key, so we have to sequentially look to all of them until the needed one is |
1806 | * found. This function returns zero in case of success, %-ENOENT if the node |
1807 | * was not found, and a negative error code in case of failure. |
1808 | */ |
1809 | static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key, |
1810 | void *node, const struct qstr *nm) |
1811 | { |
1812 | int found, n, err; |
1813 | struct ubifs_znode *znode; |
1814 | |
1815 | dbg_tnc("name '%.*s' key %s", nm->len, nm->name, DBGKEY(key)); |
1816 | mutex_lock(&c->tnc_mutex); |
1817 | found = ubifs_lookup_level0(c, key, &znode, &n); |
1818 | if (!found) { |
1819 | err = -ENOENT; |
1820 | goto out_unlock; |
1821 | } else if (found < 0) { |
1822 | err = found; |
1823 | goto out_unlock; |
1824 | } |
1825 | |
1826 | ubifs_assert(n >= 0); |
1827 | |
1828 | err = resolve_collision(c, key, &znode, &n, nm); |
1829 | dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n); |
1830 | if (unlikely(err < 0)) |
1831 | goto out_unlock; |
1832 | if (err == 0) { |
1833 | err = -ENOENT; |
1834 | goto out_unlock; |
1835 | } |
1836 | |
1837 | err = tnc_read_node_nm(c, &znode->zbranch[n], node); |
1838 | |
1839 | out_unlock: |
1840 | mutex_unlock(&c->tnc_mutex); |
1841 | return err; |
1842 | } |
1843 | |
1844 | /** |
1845 | * ubifs_tnc_lookup_nm - look up a "hashed" node. |
1846 | * @c: UBIFS file-system description object |
1847 | * @key: node key to lookup |
1848 | * @node: the node is returned here |
1849 | * @nm: node name |
1850 | * |
1851 | * This function look up and reads a node which contains name hash in the key. |
1852 | * Since the hash may have collisions, there may be many nodes with the same |
1853 | * key, so we have to sequentially look to all of them until the needed one is |
1854 | * found. This function returns zero in case of success, %-ENOENT if the node |
1855 | * was not found, and a negative error code in case of failure. |
1856 | */ |
1857 | int ubifs_tnc_lookup_nm(struct ubifs_info *c, const union ubifs_key *key, |
1858 | void *node, const struct qstr *nm) |
1859 | { |
1860 | int err, len; |
1861 | const struct ubifs_dent_node *dent = node; |
1862 | |
1863 | /* |
1864 | * We assume that in most of the cases there are no name collisions and |
1865 | * 'ubifs_tnc_lookup()' returns us the right direntry. |
1866 | */ |
1867 | err = ubifs_tnc_lookup(c, key, node); |
1868 | if (err) |
1869 | return err; |
1870 | |
1871 | len = le16_to_cpu(dent->nlen); |
1872 | if (nm->len == len && !memcmp(dent->name, nm->name, len)) |
1873 | return 0; |
1874 | |
1875 | /* |
1876 | * Unluckily, there are hash collisions and we have to iterate over |
1877 | * them look at each direntry with colliding name hash sequentially. |
1878 | */ |
1879 | return do_lookup_nm(c, key, node, nm); |
1880 | } |
1881 | |
1882 | /** |
1883 | * correct_parent_keys - correct parent znodes' keys. |
1884 | * @c: UBIFS file-system description object |
1885 | * @znode: znode to correct parent znodes for |
1886 | * |
1887 | * This is a helper function for 'tnc_insert()'. When the key of the leftmost |
1888 | * zbranch changes, keys of parent znodes have to be corrected. This helper |
1889 | * function is called in such situations and corrects the keys if needed. |
1890 | */ |
1891 | static void correct_parent_keys(const struct ubifs_info *c, |
1892 | struct ubifs_znode *znode) |
1893 | { |
1894 | union ubifs_key *key, *key1; |
1895 | |
1896 | ubifs_assert(znode->parent); |
1897 | ubifs_assert(znode->iip == 0); |
1898 | |
1899 | key = &znode->zbranch[0].key; |
1900 | key1 = &znode->parent->zbranch[0].key; |
1901 | |
1902 | while (keys_cmp(c, key, key1) < 0) { |
1903 | key_copy(c, key, key1); |
1904 | znode = znode->parent; |
1905 | znode->alt = 1; |
1906 | if (!znode->parent || znode->iip) |
1907 | break; |
1908 | key1 = &znode->parent->zbranch[0].key; |
1909 | } |
1910 | } |
1911 | |
1912 | /** |
1913 | * insert_zbranch - insert a zbranch into a znode. |
1914 | * @znode: znode into which to insert |
1915 | * @zbr: zbranch to insert |
1916 | * @n: slot number to insert to |
1917 | * |
1918 | * This is a helper function for 'tnc_insert()'. UBIFS does not allow "gaps" in |
1919 | * znode's array of zbranches and keeps zbranches consolidated, so when a new |
1920 | * zbranch has to be inserted to the @znode->zbranches[]' array at the @n-th |
1921 | * slot, zbranches starting from @n have to be moved right. |
1922 | */ |
1923 | static void insert_zbranch(struct ubifs_znode *znode, |
1924 | const struct ubifs_zbranch *zbr, int n) |
1925 | { |
1926 | int i; |
1927 | |
1928 | ubifs_assert(ubifs_zn_dirty(znode)); |
1929 | |
1930 | if (znode->level) { |
1931 | for (i = znode->child_cnt; i > n; i--) { |
1932 | znode->zbranch[i] = znode->zbranch[i - 1]; |
1933 | if (znode->zbranch[i].znode) |
1934 | znode->zbranch[i].znode->iip = i; |
1935 | } |
1936 | if (zbr->znode) |
1937 | zbr->znode->iip = n; |
1938 | } else |
1939 | for (i = znode->child_cnt; i > n; i--) |
1940 | znode->zbranch[i] = znode->zbranch[i - 1]; |
1941 | |
1942 | znode->zbranch[n] = *zbr; |
1943 | znode->child_cnt += 1; |
1944 | |
1945 | /* |
1946 | * After inserting at slot zero, the lower bound of the key range of |
1947 | * this znode may have changed. If this znode is subsequently split |
1948 | * then the upper bound of the key range may change, and furthermore |
1949 | * it could change to be lower than the original lower bound. If that |
1950 | * happens, then it will no longer be possible to find this znode in the |
1951 | * TNC using the key from the index node on flash. That is bad because |
1952 | * if it is not found, we will assume it is obsolete and may overwrite |
1953 | * it. Then if there is an unclean unmount, we will start using the |
1954 | * old index which will be broken. |
1955 | * |
1956 | * So we first mark znodes that have insertions at slot zero, and then |
1957 | * if they are split we add their lnum/offs to the old_idx tree. |
1958 | */ |
1959 | if (n == 0) |
1960 | znode->alt = 1; |
1961 | } |
1962 | |
1963 | /** |
1964 | * tnc_insert - insert a node into TNC. |
1965 | * @c: UBIFS file-system description object |
1966 | * @znode: znode to insert into |
1967 | * @zbr: branch to insert |
1968 | * @n: slot number to insert new zbranch to |
1969 | * |
1970 | * This function inserts a new node described by @zbr into znode @znode. If |
1971 | * znode does not have a free slot for new zbranch, it is split. Parent znodes |
1972 | * are splat as well if needed. Returns zero in case of success or a negative |
1973 | * error code in case of failure. |
1974 | */ |
1975 | static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode, |
1976 | struct ubifs_zbranch *zbr, int n) |
1977 | { |
1978 | struct ubifs_znode *zn, *zi, *zp; |
1979 | int i, keep, move, appending = 0; |
1980 | union ubifs_key *key = &zbr->key, *key1; |
1981 | |
1982 | ubifs_assert(n >= 0 && n <= c->fanout); |
1983 | |
1984 | /* Implement naive insert for now */ |
1985 | again: |
1986 | zp = znode->parent; |
1987 | if (znode->child_cnt < c->fanout) { |
1988 | ubifs_assert(n != c->fanout); |
1989 | dbg_tnc("inserted at %d level %d, key %s", n, znode->level, |
1990 | DBGKEY(key)); |
1991 | |
1992 | insert_zbranch(znode, zbr, n); |
1993 | |
1994 | /* Ensure parent's key is correct */ |
1995 | if (n == 0 && zp && znode->iip == 0) |
1996 | correct_parent_keys(c, znode); |
1997 | |
1998 | return 0; |
1999 | } |
2000 | |
2001 | /* |
2002 | * Unfortunately, @znode does not have more empty slots and we have to |
2003 | * split it. |
2004 | */ |
2005 | dbg_tnc("splitting level %d, key %s", znode->level, DBGKEY(key)); |
2006 | |
2007 | if (znode->alt) |
2008 | /* |
2009 | * We can no longer be sure of finding this znode by key, so we |
2010 | * record it in the old_idx tree. |
2011 | */ |
2012 | ins_clr_old_idx_znode(c, znode); |
2013 | |
2014 | zn = kzalloc(c->max_znode_sz, GFP_NOFS); |
2015 | if (!zn) |
2016 | return -ENOMEM; |
2017 | zn->parent = zp; |
2018 | zn->level = znode->level; |
2019 | |
2020 | /* Decide where to split */ |
2021 | if (znode->level == 0 && key_type(c, key) == UBIFS_DATA_KEY) { |
2022 | /* Try not to split consecutive data keys */ |
2023 | if (n == c->fanout) { |
2024 | key1 = &znode->zbranch[n - 1].key; |
2025 | if (key_inum(c, key1) == key_inum(c, key) && |
2026 | key_type(c, key1) == UBIFS_DATA_KEY) |
2027 | appending = 1; |
2028 | } else |
2029 | goto check_split; |
2030 | } else if (appending && n != c->fanout) { |
2031 | /* Try not to split consecutive data keys */ |
2032 | appending = 0; |
2033 | check_split: |
2034 | if (n >= (c->fanout + 1) / 2) { |
2035 | key1 = &znode->zbranch[0].key; |
2036 | if (key_inum(c, key1) == key_inum(c, key) && |
2037 | key_type(c, key1) == UBIFS_DATA_KEY) { |
2038 | key1 = &znode->zbranch[n].key; |
2039 | if (key_inum(c, key1) != key_inum(c, key) || |
2040 | key_type(c, key1) != UBIFS_DATA_KEY) { |
2041 | keep = n; |
2042 | move = c->fanout - keep; |
2043 | zi = znode; |
2044 | goto do_split; |
2045 | } |
2046 | } |
2047 | } |
2048 | } |
2049 | |
2050 | if (appending) { |
2051 | keep = c->fanout; |
2052 | move = 0; |
2053 | } else { |
2054 | keep = (c->fanout + 1) / 2; |
2055 | move = c->fanout - keep; |
2056 | } |
2057 | |
2058 | /* |
2059 | * Although we don't at present, we could look at the neighbors and see |
2060 | * if we can move some zbranches there. |
2061 | */ |
2062 | |
2063 | if (n < keep) { |
2064 | /* Insert into existing znode */ |
2065 | zi = znode; |
2066 | move += 1; |
2067 | keep -= 1; |
2068 | } else { |
2069 | /* Insert into new znode */ |
2070 | zi = zn; |
2071 | n -= keep; |
2072 | /* Re-parent */ |
2073 | if (zn->level != 0) |
2074 | zbr->znode->parent = zn; |
2075 | } |
2076 | |
2077 | do_split: |
2078 | |
2079 | __set_bit(DIRTY_ZNODE, &zn->flags); |
2080 | atomic_long_inc(&c->dirty_zn_cnt); |
2081 | |
2082 | zn->child_cnt = move; |
2083 | znode->child_cnt = keep; |
2084 | |
2085 | dbg_tnc("moving %d, keeping %d", move, keep); |
2086 | |
2087 | /* Move zbranch */ |
2088 | for (i = 0; i < move; i++) { |
2089 | zn->zbranch[i] = znode->zbranch[keep + i]; |
2090 | /* Re-parent */ |
2091 | if (zn->level != 0) |
2092 | if (zn->zbranch[i].znode) { |
2093 | zn->zbranch[i].znode->parent = zn; |
2094 | zn->zbranch[i].znode->iip = i; |
2095 | } |
2096 | } |
2097 | |
2098 | /* Insert new key and branch */ |
2099 | dbg_tnc("inserting at %d level %d, key %s", n, zn->level, DBGKEY(key)); |
2100 | |
2101 | insert_zbranch(zi, zbr, n); |
2102 | |
2103 | /* Insert new znode (produced by spitting) into the parent */ |
2104 | if (zp) { |
2105 | if (n == 0 && zi == znode && znode->iip == 0) |
2106 | correct_parent_keys(c, znode); |
2107 | |
2108 | /* Locate insertion point */ |
2109 | n = znode->iip + 1; |
2110 | |
2111 | /* Tail recursion */ |
2112 | zbr->key = zn->zbranch[0].key; |
2113 | zbr->znode = zn; |
2114 | zbr->lnum = 0; |
2115 | zbr->offs = 0; |
2116 | zbr->len = 0; |
2117 | znode = zp; |
2118 | |
2119 | goto again; |
2120 | } |
2121 | |
2122 | /* We have to split root znode */ |
2123 | dbg_tnc("creating new zroot at level %d", znode->level + 1); |
2124 | |
2125 | zi = kzalloc(c->max_znode_sz, GFP_NOFS); |
2126 | if (!zi) |
2127 | return -ENOMEM; |
2128 | |
2129 | zi->child_cnt = 2; |
2130 | zi->level = znode->level + 1; |
2131 | |
2132 | __set_bit(DIRTY_ZNODE, &zi->flags); |
2133 | atomic_long_inc(&c->dirty_zn_cnt); |
2134 | |
2135 | zi->zbranch[0].key = znode->zbranch[0].key; |
2136 | zi->zbranch[0].znode = znode; |
2137 | zi->zbranch[0].lnum = c->zroot.lnum; |
2138 | zi->zbranch[0].offs = c->zroot.offs; |
2139 | zi->zbranch[0].len = c->zroot.len; |
2140 | zi->zbranch[1].key = zn->zbranch[0].key; |
2141 | zi->zbranch[1].znode = zn; |
2142 | |
2143 | c->zroot.lnum = 0; |
2144 | c->zroot.offs = 0; |
2145 | c->zroot.len = 0; |
2146 | c->zroot.znode = zi; |
2147 | |
2148 | zn->parent = zi; |
2149 | zn->iip = 1; |
2150 | znode->parent = zi; |
2151 | znode->iip = 0; |
2152 | |
2153 | return 0; |
2154 | } |
2155 | |
2156 | /** |
2157 | * ubifs_tnc_add - add a node to TNC. |
2158 | * @c: UBIFS file-system description object |
2159 | * @key: key to add |
2160 | * @lnum: LEB number of node |
2161 | * @offs: node offset |
2162 | * @len: node length |
2163 | * |
2164 | * This function adds a node with key @key to TNC. The node may be new or it may |
2165 | * obsolete some existing one. Returns %0 on success or negative error code on |
2166 | * failure. |
2167 | */ |
2168 | int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum, |
2169 | int offs, int len) |
2170 | { |
2171 | int found, n, err = 0; |
2172 | struct ubifs_znode *znode; |
2173 | |
2174 | mutex_lock(&c->tnc_mutex); |
2175 | dbg_tnc("%d:%d, len %d, key %s", lnum, offs, len, DBGKEY(key)); |
2176 | found = lookup_level0_dirty(c, key, &znode, &n); |
2177 | if (!found) { |
2178 | struct ubifs_zbranch zbr; |
2179 | |
2180 | zbr.znode = NULL; |
2181 | zbr.lnum = lnum; |
2182 | zbr.offs = offs; |
2183 | zbr.len = len; |
2184 | key_copy(c, key, &zbr.key); |
2185 | err = tnc_insert(c, znode, &zbr, n + 1); |
2186 | } else if (found == 1) { |
2187 | struct ubifs_zbranch *zbr = &znode->zbranch[n]; |
2188 | |
2189 | lnc_free(zbr); |
2190 | err = ubifs_add_dirt(c, zbr->lnum, zbr->len); |
2191 | zbr->lnum = lnum; |
2192 | zbr->offs = offs; |
2193 | zbr->len = len; |
2194 | } else |
2195 | err = found; |
2196 | if (!err) |
2197 | err = dbg_check_tnc(c, 0); |
2198 | mutex_unlock(&c->tnc_mutex); |
2199 | |
2200 | return err; |
2201 | } |
2202 | |
2203 | /** |
2204 | * ubifs_tnc_replace - replace a node in the TNC only if the old node is found. |
2205 | * @c: UBIFS file-system description object |
2206 | * @key: key to add |
2207 | * @old_lnum: LEB number of old node |
2208 | * @old_offs: old node offset |
2209 | * @lnum: LEB number of node |
2210 | * @offs: node offset |
2211 | * @len: node length |
2212 | * |
2213 | * This function replaces a node with key @key in the TNC only if the old node |
2214 | * is found. This function is called by garbage collection when node are moved. |
2215 | * Returns %0 on success or negative error code on failure. |
2216 | */ |
2217 | int ubifs_tnc_replace(struct ubifs_info *c, const union ubifs_key *key, |
2218 | int old_lnum, int old_offs, int lnum, int offs, int len) |
2219 | { |
2220 | int found, n, err = 0; |
2221 | struct ubifs_znode *znode; |
2222 | |
2223 | mutex_lock(&c->tnc_mutex); |
2224 | dbg_tnc("old LEB %d:%d, new LEB %d:%d, len %d, key %s", old_lnum, |
2225 | old_offs, lnum, offs, len, DBGKEY(key)); |
2226 | found = lookup_level0_dirty(c, key, &znode, &n); |
2227 | if (found < 0) { |
2228 | err = found; |
2229 | goto out_unlock; |
2230 | } |
2231 | |
2232 | if (found == 1) { |
2233 | struct ubifs_zbranch *zbr = &znode->zbranch[n]; |
2234 | |
2235 | found = 0; |
2236 | if (zbr->lnum == old_lnum && zbr->offs == old_offs) { |
2237 | lnc_free(zbr); |
2238 | err = ubifs_add_dirt(c, zbr->lnum, zbr->len); |
2239 | if (err) |
2240 | goto out_unlock; |
2241 | zbr->lnum = lnum; |
2242 | zbr->offs = offs; |
2243 | zbr->len = len; |
2244 | found = 1; |
2245 | } else if (is_hash_key(c, key)) { |
2246 | found = resolve_collision_directly(c, key, &znode, &n, |
2247 | old_lnum, old_offs); |
2248 | dbg_tnc("rc returned %d, znode %p, n %d, LEB %d:%d", |
2249 | found, znode, n, old_lnum, old_offs); |
2250 | if (found < 0) { |
2251 | err = found; |
2252 | goto out_unlock; |
2253 | } |
2254 | |
2255 | if (found) { |
2256 | /* Ensure the znode is dirtied */ |
2257 | if (znode->cnext || !ubifs_zn_dirty(znode)) { |
2258 | znode = dirty_cow_bottom_up(c, znode); |
2259 | if (IS_ERR(znode)) { |
2260 | err = PTR_ERR(znode); |
2261 | goto out_unlock; |
2262 | } |
2263 | } |
2264 | zbr = &znode->zbranch[n]; |
2265 | lnc_free(zbr); |
2266 | err = ubifs_add_dirt(c, zbr->lnum, |
2267 | zbr->len); |
2268 | if (err) |
2269 | goto out_unlock; |
2270 | zbr->lnum = lnum; |
2271 | zbr->offs = offs; |
2272 | zbr->len = len; |
2273 | } |
2274 | } |
2275 | } |
2276 | |
2277 | if (!found) |
2278 | err = ubifs_add_dirt(c, lnum, len); |
2279 | |
2280 | if (!err) |
2281 | err = dbg_check_tnc(c, 0); |
2282 | |
2283 | out_unlock: |
2284 | mutex_unlock(&c->tnc_mutex); |
2285 | return err; |
2286 | } |
2287 | |
2288 | /** |
2289 | * ubifs_tnc_add_nm - add a "hashed" node to TNC. |
2290 | * @c: UBIFS file-system description object |
2291 | * @key: key to add |
2292 | * @lnum: LEB number of node |
2293 | * @offs: node offset |
2294 | * @len: node length |
2295 | * @nm: node name |
2296 | * |
2297 | * This is the same as 'ubifs_tnc_add()' but it should be used with keys which |
2298 | * may have collisions, like directory entry keys. |
2299 | */ |
2300 | int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key, |
2301 | int lnum, int offs, int len, const struct qstr *nm) |
2302 | { |
2303 | int found, n, err = 0; |
2304 | struct ubifs_znode *znode; |
2305 | |
2306 | mutex_lock(&c->tnc_mutex); |
2307 | dbg_tnc("LEB %d:%d, name '%.*s', key %s", lnum, offs, nm->len, nm->name, |
2308 | DBGKEY(key)); |
2309 | found = lookup_level0_dirty(c, key, &znode, &n); |
2310 | if (found < 0) { |
2311 | err = found; |
2312 | goto out_unlock; |
2313 | } |
2314 | |
2315 | if (found == 1) { |
2316 | if (c->replaying) |
2317 | found = fallible_resolve_collision(c, key, &znode, &n, |
2318 | nm, 1); |
2319 | else |
2320 | found = resolve_collision(c, key, &znode, &n, nm); |
2321 | dbg_tnc("rc returned %d, znode %p, n %d", found, znode, n); |
2322 | if (found < 0) { |
2323 | err = found; |
2324 | goto out_unlock; |
2325 | } |
2326 | |
2327 | /* Ensure the znode is dirtied */ |
2328 | if (znode->cnext || !ubifs_zn_dirty(znode)) { |
2329 | znode = dirty_cow_bottom_up(c, znode); |
2330 | if (IS_ERR(znode)) { |
2331 | err = PTR_ERR(znode); |
2332 | goto out_unlock; |
2333 | } |
2334 | } |
2335 | |
2336 | if (found == 1) { |
2337 | struct ubifs_zbranch *zbr = &znode->zbranch[n]; |
2338 | |
2339 | lnc_free(zbr); |
2340 | err = ubifs_add_dirt(c, zbr->lnum, zbr->len); |
2341 | zbr->lnum = lnum; |
2342 | zbr->offs = offs; |
2343 | zbr->len = len; |
2344 | goto out_unlock; |
2345 | } |
2346 | } |
2347 | |
2348 | if (!found) { |
2349 | struct ubifs_zbranch zbr; |
2350 | |
2351 | zbr.znode = NULL; |
2352 | zbr.lnum = lnum; |
2353 | zbr.offs = offs; |
2354 | zbr.len = len; |
2355 | key_copy(c, key, &zbr.key); |
2356 | err = tnc_insert(c, znode, &zbr, n + 1); |
2357 | if (err) |
2358 | goto out_unlock; |
2359 | if (c->replaying) { |
2360 | /* |
2361 | * We did not find it in the index so there may be a |
2362 | * dangling branch still in the index. So we remove it |
2363 | * by passing 'ubifs_tnc_remove_nm()' the same key but |
2364 | * an unmatchable name. |
2365 | */ |
2366 | struct qstr noname = { .len = 0, .name = "" }; |
2367 | |
2368 | err = dbg_check_tnc(c, 0); |
2369 | mutex_unlock(&c->tnc_mutex); |
2370 | if (err) |
2371 | return err; |
2372 | return ubifs_tnc_remove_nm(c, key, &noname); |
2373 | } |
2374 | } |
2375 | |
2376 | out_unlock: |
2377 | if (!err) |
2378 | err = dbg_check_tnc(c, 0); |
2379 | mutex_unlock(&c->tnc_mutex); |
2380 | return err; |
2381 | } |
2382 | |
2383 | /** |
2384 | * tnc_delete - delete a znode form TNC. |
2385 | * @c: UBIFS file-system description object |
2386 | * @znode: znode to delete from |
2387 | * @n: zbranch slot number to delete |
2388 | * |
2389 | * This function deletes a leaf node from @n-th slot of @znode. Returns zero in |
2390 | * case of success and a negative error code in case of failure. |
2391 | */ |
2392 | static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n) |
2393 | { |
2394 | struct ubifs_zbranch *zbr; |
2395 | struct ubifs_znode *zp; |
2396 | int i, err; |
2397 | |
2398 | /* Delete without merge for now */ |
2399 | ubifs_assert(znode->level == 0); |
2400 | ubifs_assert(n >= 0 && n < c->fanout); |
2401 | dbg_tnc("deleting %s", DBGKEY(&znode->zbranch[n].key)); |
2402 | |
2403 | zbr = &znode->zbranch[n]; |
2404 | lnc_free(zbr); |
2405 | |
2406 | err = ubifs_add_dirt(c, zbr->lnum, zbr->len); |
2407 | if (err) { |
2408 | dbg_dump_znode(c, znode); |
2409 | return err; |
2410 | } |
2411 | |
2412 | /* We do not "gap" zbranch slots */ |
2413 | for (i = n; i < znode->child_cnt - 1; i++) |
2414 | znode->zbranch[i] = znode->zbranch[i + 1]; |
2415 | znode->child_cnt -= 1; |
2416 | |
2417 | if (znode->child_cnt > 0) |
2418 | return 0; |
2419 | |
2420 | /* |
2421 | * This was the last zbranch, we have to delete this znode from the |
2422 | * parent. |
2423 | */ |
2424 | |
2425 | do { |
2426 | ubifs_assert(!test_bit(OBSOLETE_ZNODE, &znode->flags)); |
2427 | ubifs_assert(ubifs_zn_dirty(znode)); |
2428 | |
2429 | zp = znode->parent; |
2430 | n = znode->iip; |
2431 | |
2432 | atomic_long_dec(&c->dirty_zn_cnt); |
2433 | |
2434 | err = insert_old_idx_znode(c, znode); |
2435 | if (err) |
2436 | return err; |
2437 | |
2438 | if (znode->cnext) { |
2439 | __set_bit(OBSOLETE_ZNODE, &znode->flags); |
2440 | atomic_long_inc(&c->clean_zn_cnt); |
2441 | atomic_long_inc(&ubifs_clean_zn_cnt); |
2442 | } else |
2443 | kfree(znode); |
2444 | znode = zp; |
2445 | } while (znode->child_cnt == 1); /* while removing last child */ |
2446 | |
2447 | /* Remove from znode, entry n - 1 */ |
2448 | znode->child_cnt -= 1; |
2449 | ubifs_assert(znode->level != 0); |
2450 | for (i = n; i < znode->child_cnt; i++) { |
2451 | znode->zbranch[i] = znode->zbranch[i + 1]; |
2452 | if (znode->zbranch[i].znode) |
2453 | znode->zbranch[i].znode->iip = i; |
2454 | } |
2455 | |
2456 | /* |
2457 | * If this is the root and it has only 1 child then |
2458 | * collapse the tree. |
2459 | */ |
2460 | if (!znode->parent) { |
2461 | while (znode->child_cnt == 1 && znode->level != 0) { |
2462 | zp = znode; |
2463 | zbr = &znode->zbranch[0]; |
2464 | znode = get_znode(c, znode, 0); |
2465 | if (IS_ERR(znode)) |
2466 | return PTR_ERR(znode); |
2467 | znode = dirty_cow_znode(c, zbr); |
2468 | if (IS_ERR(znode)) |
2469 | return PTR_ERR(znode); |
2470 | znode->parent = NULL; |
2471 | znode->iip = 0; |
2472 | if (c->zroot.len) { |
2473 | err = insert_old_idx(c, c->zroot.lnum, |
2474 | c->zroot.offs); |
2475 | if (err) |
2476 | return err; |
2477 | } |
2478 | c->zroot.lnum = zbr->lnum; |
2479 | c->zroot.offs = zbr->offs; |
2480 | c->zroot.len = zbr->len; |
2481 | c->zroot.znode = znode; |
2482 | ubifs_assert(!test_bit(OBSOLETE_ZNODE, |
2483 | &zp->flags)); |
2484 | ubifs_assert(test_bit(DIRTY_ZNODE, &zp->flags)); |
2485 | atomic_long_dec(&c->dirty_zn_cnt); |
2486 | |
2487 | if (zp->cnext) { |
2488 | __set_bit(OBSOLETE_ZNODE, &zp->flags); |
2489 | atomic_long_inc(&c->clean_zn_cnt); |
2490 | atomic_long_inc(&ubifs_clean_zn_cnt); |
2491 | } else |
2492 | kfree(zp); |
2493 | } |
2494 | } |
2495 | |
2496 | return 0; |
2497 | } |
2498 | |
2499 | /** |
2500 | * ubifs_tnc_remove - remove an index entry of a node. |
2501 | * @c: UBIFS file-system description object |
2502 | * @key: key of node |
2503 | * |
2504 | * Returns %0 on success or negative error code on failure. |
2505 | */ |
2506 | int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key) |
2507 | { |
2508 | int found, n, err = 0; |
2509 | struct ubifs_znode *znode; |
2510 | |
2511 | mutex_lock(&c->tnc_mutex); |
2512 | dbg_tnc("key %s", DBGKEY(key)); |
2513 | found = lookup_level0_dirty(c, key, &znode, &n); |
2514 | if (found < 0) { |
2515 | err = found; |
2516 | goto out_unlock; |
2517 | } |
2518 | if (found == 1) |
2519 | err = tnc_delete(c, znode, n); |
2520 | if (!err) |
2521 | err = dbg_check_tnc(c, 0); |
2522 | |
2523 | out_unlock: |
2524 | mutex_unlock(&c->tnc_mutex); |
2525 | return err; |
2526 | } |
2527 | |
2528 | /** |
2529 | * ubifs_tnc_remove_nm - remove an index entry for a "hashed" node. |
2530 | * @c: UBIFS file-system description object |
2531 | * @key: key of node |
2532 | * @nm: directory entry name |
2533 | * |
2534 | * Returns %0 on success or negative error code on failure. |
2535 | */ |
2536 | int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key, |
2537 | const struct qstr *nm) |
2538 | { |
2539 | int n, err; |
2540 | struct ubifs_znode *znode; |
2541 | |
2542 | mutex_lock(&c->tnc_mutex); |
2543 | dbg_tnc("%.*s, key %s", nm->len, nm->name, DBGKEY(key)); |
2544 | err = lookup_level0_dirty(c, key, &znode, &n); |
2545 | if (err < 0) |
2546 | goto out_unlock; |
2547 | |
2548 | if (err) { |
2549 | if (c->replaying) |
2550 | err = fallible_resolve_collision(c, key, &znode, &n, |
2551 | nm, 0); |
2552 | else |
2553 | err = resolve_collision(c, key, &znode, &n, nm); |
2554 | dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n); |
2555 | if (err < 0) |
2556 | goto out_unlock; |
2557 | if (err) { |
2558 | /* Ensure the znode is dirtied */ |
2559 | if (znode->cnext || !ubifs_zn_dirty(znode)) { |
2560 | znode = dirty_cow_bottom_up(c, znode); |
2561 | if (IS_ERR(znode)) { |
2562 | err = PTR_ERR(znode); |
2563 | goto out_unlock; |
2564 | } |
2565 | } |
2566 | err = tnc_delete(c, znode, n); |
2567 | } |
2568 | } |
2569 | |
2570 | out_unlock: |
2571 | if (!err) |
2572 | err = dbg_check_tnc(c, 0); |
2573 | mutex_unlock(&c->tnc_mutex); |
2574 | return err; |
2575 | } |
2576 | |
2577 | /** |
2578 | * key_in_range - determine if a key falls within a range of keys. |
2579 | * @c: UBIFS file-system description object |
2580 | * @key: key to check |
2581 | * @from_key: lowest key in range |
2582 | * @to_key: highest key in range |
2583 | * |
2584 | * This function returns %1 if the key is in range and %0 otherwise. |
2585 | */ |
2586 | static int key_in_range(struct ubifs_info *c, union ubifs_key *key, |
2587 | union ubifs_key *from_key, union ubifs_key *to_key) |
2588 | { |
2589 | if (keys_cmp(c, key, from_key) < 0) |
2590 | return 0; |
2591 | if (keys_cmp(c, key, to_key) > 0) |
2592 | return 0; |
2593 | return 1; |
2594 | } |
2595 | |
2596 | /** |
2597 | * ubifs_tnc_remove_range - remove index entries in range. |
2598 | * @c: UBIFS file-system description object |
2599 | * @from_key: lowest key to remove |
2600 | * @to_key: highest key to remove |
2601 | * |
2602 | * This function removes index entries starting at @from_key and ending at |
2603 | * @to_key. This function returns zero in case of success and a negative error |
2604 | * code in case of failure. |
2605 | */ |
2606 | int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key, |
2607 | union ubifs_key *to_key) |
2608 | { |
2609 | int i, n, k, err = 0; |
2610 | struct ubifs_znode *znode; |
2611 | union ubifs_key *key; |
2612 | |
2613 | mutex_lock(&c->tnc_mutex); |
2614 | while (1) { |
2615 | /* Find first level 0 znode that contains keys to remove */ |
2616 | err = ubifs_lookup_level0(c, from_key, &znode, &n); |
2617 | if (err < 0) |
2618 | goto out_unlock; |
2619 | |
2620 | if (err) |
2621 | key = from_key; |
2622 | else { |
2623 | err = tnc_next(c, &znode, &n); |
2624 | if (err == -ENOENT) { |
2625 | err = 0; |
2626 | goto out_unlock; |
2627 | } |
2628 | if (err < 0) |
2629 | goto out_unlock; |
2630 | key = &znode->zbranch[n].key; |
2631 | if (!key_in_range(c, key, from_key, to_key)) { |
2632 | err = 0; |
2633 | goto out_unlock; |
2634 | } |
2635 | } |
2636 | |
2637 | /* Ensure the znode is dirtied */ |
2638 | if (znode->cnext || !ubifs_zn_dirty(znode)) { |
2639 | znode = dirty_cow_bottom_up(c, znode); |
2640 | if (IS_ERR(znode)) { |
2641 | err = PTR_ERR(znode); |
2642 | goto out_unlock; |
2643 | } |
2644 | } |
2645 | |
2646 | /* Remove all keys in range except the first */ |
2647 | for (i = n + 1, k = 0; i < znode->child_cnt; i++, k++) { |
2648 | key = &znode->zbranch[i].key; |
2649 | if (!key_in_range(c, key, from_key, to_key)) |
2650 | break; |
2651 | lnc_free(&znode->zbranch[i]); |
2652 | err = ubifs_add_dirt(c, znode->zbranch[i].lnum, |
2653 | znode->zbranch[i].len); |
2654 | if (err) { |
2655 | dbg_dump_znode(c, znode); |
2656 | goto out_unlock; |
2657 | } |
2658 | dbg_tnc("removing %s", DBGKEY(key)); |
2659 | } |
2660 | if (k) { |
2661 | for (i = n + 1 + k; i < znode->child_cnt; i++) |
2662 | znode->zbranch[i - k] = znode->zbranch[i]; |
2663 | znode->child_cnt -= k; |
2664 | } |
2665 | |
2666 | /* Now delete the first */ |
2667 | err = tnc_delete(c, znode, n); |
2668 | if (err) |
2669 | goto out_unlock; |
2670 | } |
2671 | |
2672 | out_unlock: |
2673 | if (!err) |
2674 | err = dbg_check_tnc(c, 0); |
2675 | mutex_unlock(&c->tnc_mutex); |
2676 | return err; |
2677 | } |
2678 | |
2679 | /** |
2680 | * ubifs_tnc_remove_ino - remove an inode from TNC. |
2681 | * @c: UBIFS file-system description object |
2682 | * @inum: inode number to remove |
2683 | * |
2684 | * This function remove inode @inum and all the extended attributes associated |
2685 | * with the anode from TNC and returns zero in case of success or a negative |
2686 | * error code in case of failure. |
2687 | */ |
2688 | int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum) |
2689 | { |
2690 | union ubifs_key key1, key2; |
2691 | struct ubifs_dent_node *xent, *pxent = NULL; |
2692 | struct qstr nm = { .name = NULL }; |
2693 | |
2694 | dbg_tnc("ino %lu", (unsigned long)inum); |
2695 | |
2696 | /* |
2697 | * Walk all extended attribute entries and remove them together with |
2698 | * corresponding extended attribute inodes. |
2699 | */ |
2700 | lowest_xent_key(c, &key1, inum); |
2701 | while (1) { |
2702 | ino_t xattr_inum; |
2703 | int err; |
2704 | |
2705 | xent = ubifs_tnc_next_ent(c, &key1, &nm); |
2706 | if (IS_ERR(xent)) { |
2707 | err = PTR_ERR(xent); |
2708 | if (err == -ENOENT) |
2709 | break; |
2710 | return err; |
2711 | } |
2712 | |
2713 | xattr_inum = le64_to_cpu(xent->inum); |
2714 | dbg_tnc("xent '%s', ino %lu", xent->name, |
2715 | (unsigned long)xattr_inum); |
2716 | |
2717 | nm.name = xent->name; |
2718 | nm.len = le16_to_cpu(xent->nlen); |
2719 | err = ubifs_tnc_remove_nm(c, &key1, &nm); |
2720 | if (err) { |
2721 | kfree(xent); |
2722 | return err; |
2723 | } |
2724 | |
2725 | lowest_ino_key(c, &key1, xattr_inum); |
2726 | highest_ino_key(c, &key2, xattr_inum); |
2727 | err = ubifs_tnc_remove_range(c, &key1, &key2); |
2728 | if (err) { |
2729 | kfree(xent); |
2730 | return err; |
2731 | } |
2732 | |
2733 | kfree(pxent); |
2734 | pxent = xent; |
2735 | key_read(c, &xent->key, &key1); |
2736 | } |
2737 | |
2738 | kfree(pxent); |
2739 | lowest_ino_key(c, &key1, inum); |
2740 | highest_ino_key(c, &key2, inum); |
2741 | |
2742 | return ubifs_tnc_remove_range(c, &key1, &key2); |
2743 | } |
2744 | |
2745 | /** |
2746 | * ubifs_tnc_next_ent - walk directory or extended attribute entries. |
2747 | * @c: UBIFS file-system description object |
2748 | * @key: key of last entry |
2749 | * @nm: name of last entry found or %NULL |
2750 | * |
2751 | * This function finds and reads the next directory or extended attribute entry |
2752 | * after the given key (@key) if there is one. @nm is used to resolve |
2753 | * collisions. |
2754 | * |
2755 | * If the name of the current entry is not known and only the key is known, |
2756 | * @nm->name has to be %NULL. In this case the semantics of this function is a |
2757 | * little bit different and it returns the entry corresponding to this key, not |
2758 | * the next one. If the key was not found, the closest "right" entry is |
2759 | * returned. |
2760 | * |
2761 | * If the fist entry has to be found, @key has to contain the lowest possible |
2762 | * key value for this inode and @name has to be %NULL. |
2763 | * |
2764 | * This function returns the found directory or extended attribute entry node |
2765 | * in case of success, %-ENOENT is returned if no entry was found, and a |
2766 | * negative error code is returned in case of failure. |
2767 | */ |
2768 | struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c, |
2769 | union ubifs_key *key, |
2770 | const struct qstr *nm) |
2771 | { |
2772 | int n, err, type = key_type(c, key); |
2773 | struct ubifs_znode *znode; |
2774 | struct ubifs_dent_node *dent; |
2775 | struct ubifs_zbranch *zbr; |
2776 | union ubifs_key *dkey; |
2777 | |
2778 | dbg_tnc("%s %s", nm->name ? (char *)nm->name : "(lowest)", DBGKEY(key)); |
2779 | ubifs_assert(is_hash_key(c, key)); |
2780 | |
2781 | mutex_lock(&c->tnc_mutex); |
2782 | err = ubifs_lookup_level0(c, key, &znode, &n); |
2783 | if (unlikely(err < 0)) |
2784 | goto out_unlock; |
2785 | |
2786 | if (nm->name) { |
2787 | if (err) { |
2788 | /* Handle collisions */ |
2789 | err = resolve_collision(c, key, &znode, &n, nm); |
2790 | dbg_tnc("rc returned %d, znode %p, n %d", |
2791 | err, znode, n); |
2792 | if (unlikely(err < 0)) |
2793 | goto out_unlock; |
2794 | } |
2795 | |
2796 | /* Now find next entry */ |
2797 | err = tnc_next(c, &znode, &n); |
2798 | if (unlikely(err)) |
2799 | goto out_unlock; |
2800 | } else { |
2801 | /* |
2802 | * The full name of the entry was not given, in which case the |
2803 | * behavior of this function is a little different and it |
2804 | * returns current entry, not the next one. |
2805 | */ |
2806 | if (!err) { |
2807 | /* |
2808 | * However, the given key does not exist in the TNC |
2809 | * tree and @znode/@n variables contain the closest |
2810 | * "preceding" element. Switch to the next one. |
2811 | */ |
2812 | err = tnc_next(c, &znode, &n); |
2813 | if (err) |
2814 | goto out_unlock; |
2815 | } |
2816 | } |
2817 | |
2818 | zbr = &znode->zbranch[n]; |
2819 | dent = kmalloc(zbr->len, GFP_NOFS); |
2820 | if (unlikely(!dent)) { |
2821 | err = -ENOMEM; |
2822 | goto out_unlock; |
2823 | } |
2824 | |
2825 | /* |
2826 | * The above 'tnc_next()' call could lead us to the next inode, check |
2827 | * this. |
2828 | */ |
2829 | dkey = &zbr->key; |
2830 | if (key_inum(c, dkey) != key_inum(c, key) || |
2831 | key_type(c, dkey) != type) { |
2832 | err = -ENOENT; |
2833 | goto out_free; |
2834 | } |
2835 | |
2836 | err = tnc_read_node_nm(c, zbr, dent); |
2837 | if (unlikely(err)) |
2838 | goto out_free; |
2839 | |
2840 | mutex_unlock(&c->tnc_mutex); |
2841 | return dent; |
2842 | |
2843 | out_free: |
2844 | kfree(dent); |
2845 | out_unlock: |
2846 | mutex_unlock(&c->tnc_mutex); |
2847 | return ERR_PTR(err); |
2848 | } |
2849 | |
2850 | /** |
2851 | * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit. |
2852 | * @c: UBIFS file-system description object |
2853 | * |
2854 | * Destroy left-over obsolete znodes from a failed commit. |
2855 | */ |
2856 | static void tnc_destroy_cnext(struct ubifs_info *c) |
2857 | { |
2858 | struct ubifs_znode *cnext; |
2859 | |
2860 | if (!c->cnext) |
2861 | return; |
2862 | ubifs_assert(c->cmt_state == COMMIT_BROKEN); |
2863 | cnext = c->cnext; |
2864 | do { |
2865 | struct ubifs_znode *znode = cnext; |
2866 | |
2867 | cnext = cnext->cnext; |
2868 | if (test_bit(OBSOLETE_ZNODE, &znode->flags)) |
2869 | kfree(znode); |
2870 | } while (cnext && cnext != c->cnext); |
2871 | } |
2872 | |
2873 | /** |
2874 | * ubifs_tnc_close - close TNC subsystem and free all related resources. |
2875 | * @c: UBIFS file-system description object |
2876 | */ |
2877 | void ubifs_tnc_close(struct ubifs_info *c) |
2878 | { |
2879 | tnc_destroy_cnext(c); |
2880 | if (c->zroot.znode) { |
2881 | long n; |
2882 | |
2883 | ubifs_destroy_tnc_subtree(c->zroot.znode); |
2884 | n = atomic_long_read(&c->clean_zn_cnt); |
2885 | atomic_long_sub(n, &ubifs_clean_zn_cnt); |
2886 | } |
2887 | kfree(c->gap_lebs); |
2888 | kfree(c->ilebs); |
2889 | destroy_old_idx(c); |
2890 | } |
2891 | |
2892 | /** |
2893 | * left_znode - get the znode to the left. |
2894 | * @c: UBIFS file-system description object |
2895 | * @znode: znode |
2896 | * |
2897 | * This function returns a pointer to the znode to the left of @znode or NULL if |
2898 | * there is not one. A negative error code is returned on failure. |
2899 | */ |
2900 | static struct ubifs_znode *left_znode(struct ubifs_info *c, |
2901 | struct ubifs_znode *znode) |
2902 | { |
2903 | int level = znode->level; |
2904 | |
2905 | while (1) { |
2906 | int n = znode->iip - 1; |
2907 | |
2908 | /* Go up until we can go left */ |
2909 | znode = znode->parent; |
2910 | if (!znode) |
2911 | return NULL; |
2912 | if (n >= 0) { |
2913 | /* Now go down the rightmost branch to 'level' */ |
2914 | znode = get_znode(c, znode, n); |
2915 | if (IS_ERR(znode)) |
2916 | return znode; |
2917 | while (znode->level != level) { |
2918 | n = znode->child_cnt - 1; |
2919 | znode = get_znode(c, znode, n); |
2920 | if (IS_ERR(znode)) |
2921 | return znode; |
2922 | } |
2923 | break; |
2924 | } |
2925 | } |
2926 | return znode; |
2927 | } |
2928 | |
2929 | /** |
2930 | * right_znode - get the znode to the right. |
2931 | * @c: UBIFS file-system description object |
2932 | * @znode: znode |
2933 | * |
2934 | * This function returns a pointer to the znode to the right of @znode or NULL |
2935 | * if there is not one. A negative error code is returned on failure. |
2936 | */ |
2937 | static struct ubifs_znode *right_znode(struct ubifs_info *c, |
2938 | struct ubifs_znode *znode) |
2939 | { |
2940 | int level = znode->level; |
2941 | |
2942 | while (1) { |
2943 | int n = znode->iip + 1; |
2944 | |
2945 | /* Go up until we can go right */ |
2946 | znode = znode->parent; |
2947 | if (!znode) |
2948 | return NULL; |
2949 | if (n < znode->child_cnt) { |
2950 | /* Now go down the leftmost branch to 'level' */ |
2951 | znode = get_znode(c, znode, n); |
2952 | if (IS_ERR(znode)) |
2953 | return znode; |
2954 | while (znode->level != level) { |
2955 | znode = get_znode(c, znode, 0); |
2956 | if (IS_ERR(znode)) |
2957 | return znode; |
2958 | } |
2959 | break; |
2960 | } |
2961 | } |
2962 | return znode; |
2963 | } |
2964 | |
2965 | /** |
2966 | * lookup_znode - find a particular indexing node from TNC. |
2967 | * @c: UBIFS file-system description object |
2968 | * @key: index node key to lookup |
2969 | * @level: index node level |
2970 | * @lnum: index node LEB number |
2971 | * @offs: index node offset |
2972 | * |
2973 | * This function searches an indexing node by its first key @key and its |
2974 | * address @lnum:@offs. It looks up the indexing tree by pulling all indexing |
2975 | * nodes it traverses to TNC. This function is called for indexing nodes which |
2976 | * were found on the media by scanning, for example when garbage-collecting or |
2977 | * when doing in-the-gaps commit. This means that the indexing node which is |
2978 | * looked for does not have to have exactly the same leftmost key @key, because |
2979 | * the leftmost key may have been changed, in which case TNC will contain a |
2980 | * dirty znode which still refers the same @lnum:@offs. This function is clever |
2981 | * enough to recognize such indexing nodes. |
2982 | * |
2983 | * Note, if a znode was deleted or changed too much, then this function will |
2984 | * not find it. For situations like this UBIFS has the old index RB-tree |
2985 | * (indexed by @lnum:@offs). |
2986 | * |
2987 | * This function returns a pointer to the znode found or %NULL if it is not |
2988 | * found. A negative error code is returned on failure. |
2989 | */ |
2990 | static struct ubifs_znode *lookup_znode(struct ubifs_info *c, |
2991 | union ubifs_key *key, int level, |
2992 | int lnum, int offs) |
2993 | { |
2994 | struct ubifs_znode *znode, *zn; |
2995 | int n, nn; |
2996 | |
2997 | ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY); |
2998 | |
2999 | /* |
3000 | * The arguments have probably been read off flash, so don't assume |
3001 | * they are valid. |
3002 | */ |
3003 | if (level < 0) |
3004 | return ERR_PTR(-EINVAL); |
3005 | |
3006 | /* Get the root znode */ |
3007 | znode = c->zroot.znode; |
3008 | if (!znode) { |
3009 | znode = ubifs_load_znode(c, &c->zroot, NULL, 0); |
3010 | if (IS_ERR(znode)) |
3011 | return znode; |
3012 | } |
3013 | /* Check if it is the one we are looking for */ |
3014 | if (c->zroot.lnum == lnum && c->zroot.offs == offs) |
3015 | return znode; |
3016 | /* Descend to the parent level i.e. (level + 1) */ |
3017 | if (level >= znode->level) |
3018 | return NULL; |
3019 | while (1) { |
3020 | ubifs_search_zbranch(c, znode, key, &n); |
3021 | if (n < 0) { |
3022 | /* |
3023 | * We reached a znode where the leftmost key is greater |
3024 | * than the key we are searching for. This is the same |
3025 | * situation as the one described in a huge comment at |
3026 | * the end of the 'ubifs_lookup_level0()' function. And |
3027 | * for exactly the same reasons we have to try to look |
3028 | * left before giving up. |
3029 | */ |
3030 | znode = left_znode(c, znode); |
3031 | if (!znode) |
3032 | return NULL; |
3033 | if (IS_ERR(znode)) |
3034 | return znode; |
3035 | ubifs_search_zbranch(c, znode, key, &n); |
3036 | ubifs_assert(n >= 0); |
3037 | } |
3038 | if (znode->level == level + 1) |
3039 | break; |
3040 | znode = get_znode(c, znode, n); |
3041 | if (IS_ERR(znode)) |
3042 | return znode; |
3043 | } |
3044 | /* Check if the child is the one we are looking for */ |
3045 | if (znode->zbranch[n].lnum == lnum && znode->zbranch[n].offs == offs) |
3046 | return get_znode(c, znode, n); |
3047 | /* If the key is unique, there is nowhere else to look */ |
3048 | if (!is_hash_key(c, key)) |
3049 | return NULL; |
3050 | /* |
3051 | * The key is not unique and so may be also in the znodes to either |
3052 | * side. |
3053 | */ |
3054 | zn = znode; |
3055 | nn = n; |
3056 | /* Look left */ |
3057 | while (1) { |
3058 | /* Move one branch to the left */ |
3059 | if (n) |
3060 | n -= 1; |
3061 | else { |
3062 | znode = left_znode(c, znode); |
3063 | if (!znode) |
3064 | break; |
3065 | if (IS_ERR(znode)) |
3066 | return znode; |
3067 | n = znode->child_cnt - 1; |
3068 | } |
3069 | /* Check it */ |
3070 | if (znode->zbranch[n].lnum == lnum && |
3071 | znode->zbranch[n].offs == offs) |
3072 | return get_znode(c, znode, n); |
3073 | /* Stop if the key is less than the one we are looking for */ |
3074 | if (keys_cmp(c, &znode->zbranch[n].key, key) < 0) |
3075 | break; |
3076 | } |
3077 | /* Back to the middle */ |
3078 | znode = zn; |
3079 | n = nn; |
3080 | /* Look right */ |
3081 | while (1) { |
3082 | /* Move one branch to the right */ |
3083 | if (++n >= znode->child_cnt) { |
3084 | znode = right_znode(c, znode); |
3085 | if (!znode) |
3086 | break; |
3087 | if (IS_ERR(znode)) |
3088 | return znode; |
3089 | n = 0; |
3090 | } |
3091 | /* Check it */ |
3092 | if (znode->zbranch[n].lnum == lnum && |
3093 | znode->zbranch[n].offs == offs) |
3094 | return get_znode(c, znode, n); |
3095 | /* Stop if the key is greater than the one we are looking for */ |
3096 | if (keys_cmp(c, &znode->zbranch[n].key, key) > 0) |
3097 | break; |
3098 | } |
3099 | return NULL; |
3100 | } |
3101 | |
3102 | /** |
3103 | * is_idx_node_in_tnc - determine if an index node is in the TNC. |
3104 | * @c: UBIFS file-system description object |
3105 | * @key: key of index node |
3106 | * @level: index node level |
3107 | * @lnum: LEB number of index node |
3108 | * @offs: offset of index node |
3109 | * |
3110 | * This function returns %0 if the index node is not referred to in the TNC, %1 |
3111 | * if the index node is referred to in the TNC and the corresponding znode is |
3112 | * dirty, %2 if an index node is referred to in the TNC and the corresponding |
3113 | * znode is clean, and a negative error code in case of failure. |
3114 | * |
3115 | * Note, the @key argument has to be the key of the first child. Also note, |
3116 | * this function relies on the fact that 0:0 is never a valid LEB number and |
3117 | * offset for a main-area node. |
3118 | */ |
3119 | int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level, |
3120 | int lnum, int offs) |
3121 | { |
3122 | struct ubifs_znode *znode; |
3123 | |
3124 | znode = lookup_znode(c, key, level, lnum, offs); |
3125 | if (!znode) |
3126 | return 0; |
3127 | if (IS_ERR(znode)) |
3128 | return PTR_ERR(znode); |
3129 | |
3130 | return ubifs_zn_dirty(znode) ? 1 : 2; |
3131 | } |
3132 | |
3133 | /** |
3134 | * is_leaf_node_in_tnc - determine if a non-indexing not is in the TNC. |
3135 | * @c: UBIFS file-system description object |
3136 | * @key: node key |
3137 | * @lnum: node LEB number |
3138 | * @offs: node offset |
3139 | * |
3140 | * This function returns %1 if the node is referred to in the TNC, %0 if it is |
3141 | * not, and a negative error code in case of failure. |
3142 | * |
3143 | * Note, this function relies on the fact that 0:0 is never a valid LEB number |
3144 | * and offset for a main-area node. |
3145 | */ |
3146 | static int is_leaf_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, |
3147 | int lnum, int offs) |
3148 | { |
3149 | struct ubifs_zbranch *zbr; |
3150 | struct ubifs_znode *znode, *zn; |
3151 | int n, found, err, nn; |
3152 | const int unique = !is_hash_key(c, key); |
3153 | |
3154 | found = ubifs_lookup_level0(c, key, &znode, &n); |
3155 | if (found < 0) |
3156 | return found; /* Error code */ |
3157 | if (!found) |
3158 | return 0; |
3159 | zbr = &znode->zbranch[n]; |
3160 | if (lnum == zbr->lnum && offs == zbr->offs) |
3161 | return 1; /* Found it */ |
3162 | if (unique) |
3163 | return 0; |
3164 | /* |
3165 | * Because the key is not unique, we have to look left |
3166 | * and right as well |
3167 | */ |
3168 | zn = znode; |
3169 | nn = n; |
3170 | /* Look left */ |
3171 | while (1) { |
3172 | err = tnc_prev(c, &znode, &n); |
3173 | if (err == -ENOENT) |
3174 | break; |
3175 | if (err) |
3176 | return err; |
3177 | if (keys_cmp(c, key, &znode->zbranch[n].key)) |
3178 | break; |
3179 | zbr = &znode->zbranch[n]; |
3180 | if (lnum == zbr->lnum && offs == zbr->offs) |
3181 | return 1; /* Found it */ |
3182 | } |
3183 | /* Look right */ |
3184 | znode = zn; |
3185 | n = nn; |
3186 | while (1) { |
3187 | err = tnc_next(c, &znode, &n); |
3188 | if (err) { |
3189 | if (err == -ENOENT) |
3190 | return 0; |
3191 | return err; |
3192 | } |
3193 | if (keys_cmp(c, key, &znode->zbranch[n].key)) |
3194 | break; |
3195 | zbr = &znode->zbranch[n]; |
3196 | if (lnum == zbr->lnum && offs == zbr->offs) |
3197 | return 1; /* Found it */ |
3198 | } |
3199 | return 0; |
3200 | } |
3201 | |
3202 | /** |
3203 | * ubifs_tnc_has_node - determine whether a node is in the TNC. |
3204 | * @c: UBIFS file-system description object |
3205 | * @key: node key |
3206 | * @level: index node level (if it is an index node) |
3207 | * @lnum: node LEB number |
3208 | * @offs: node offset |
3209 | * @is_idx: non-zero if the node is an index node |
3210 | * |
3211 | * This function returns %1 if the node is in the TNC, %0 if it is not, and a |
3212 | * negative error code in case of failure. For index nodes, @key has to be the |
3213 | * key of the first child. An index node is considered to be in the TNC only if |
3214 | * the corresponding znode is clean or has not been loaded. |
3215 | */ |
3216 | int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level, |
3217 | int lnum, int offs, int is_idx) |
3218 | { |
3219 | int err; |
3220 | |
3221 | mutex_lock(&c->tnc_mutex); |
3222 | if (is_idx) { |
3223 | err = is_idx_node_in_tnc(c, key, level, lnum, offs); |
3224 | if (err < 0) |
3225 | goto out_unlock; |
3226 | if (err == 1) |
3227 | /* The index node was found but it was dirty */ |
3228 | err = 0; |
3229 | else if (err == 2) |
3230 | /* The index node was found and it was clean */ |
3231 | err = 1; |
3232 | else |
3233 | BUG_ON(err != 0); |
3234 | } else |
3235 | err = is_leaf_node_in_tnc(c, key, lnum, offs); |
3236 | |
3237 | out_unlock: |
3238 | mutex_unlock(&c->tnc_mutex); |
3239 | return err; |
3240 | } |
3241 | |
3242 | /** |
3243 | * ubifs_dirty_idx_node - dirty an index node. |
3244 | * @c: UBIFS file-system description object |
3245 | * @key: index node key |
3246 | * @level: index node level |
3247 | * @lnum: index node LEB number |
3248 | * @offs: index node offset |
3249 | * |
3250 | * This function loads and dirties an index node so that it can be garbage |
3251 | * collected. The @key argument has to be the key of the first child. This |
3252 | * function relies on the fact that 0:0 is never a valid LEB number and offset |
3253 | * for a main-area node. Returns %0 on success and a negative error code on |
3254 | * failure. |
3255 | */ |
3256 | int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level, |
3257 | int lnum, int offs) |
3258 | { |
3259 | struct ubifs_znode *znode; |
3260 | int err = 0; |
3261 | |
3262 | mutex_lock(&c->tnc_mutex); |
3263 | znode = lookup_znode(c, key, level, lnum, offs); |
3264 | if (!znode) |
3265 | goto out_unlock; |
3266 | if (IS_ERR(znode)) { |
3267 | err = PTR_ERR(znode); |
3268 | goto out_unlock; |
3269 | } |
3270 | znode = dirty_cow_bottom_up(c, znode); |
3271 | if (IS_ERR(znode)) { |
3272 | err = PTR_ERR(znode); |
3273 | goto out_unlock; |
3274 | } |
3275 | |
3276 | out_unlock: |
3277 | mutex_unlock(&c->tnc_mutex); |
3278 | return err; |
3279 | } |
3280 | |
3281 | #ifdef CONFIG_UBIFS_FS_DEBUG |
3282 | |
3283 | /** |
3284 | * dbg_check_inode_size - check if inode size is correct. |
3285 | * @c: UBIFS file-system description object |
3286 | * @inum: inode number |
3287 | * @size: inode size |
3288 | * |
3289 | * This function makes sure that the inode size (@size) is correct and it does |
3290 | * not have any pages beyond @size. Returns zero if the inode is OK, %-EINVAL |
3291 | * if it has a data page beyond @size, and other negative error code in case of |
3292 | * other errors. |
3293 | */ |
3294 | int dbg_check_inode_size(struct ubifs_info *c, const struct inode *inode, |
3295 | loff_t size) |
3296 | { |
3297 | int err, n; |
3298 | union ubifs_key from_key, to_key, *key; |
3299 | struct ubifs_znode *znode; |
3300 | unsigned int block; |
3301 | |
3302 | if (!S_ISREG(inode->i_mode)) |
3303 | return 0; |
3304 | if (!(ubifs_chk_flags & UBIFS_CHK_GEN)) |
3305 | return 0; |
3306 | |
3307 | block = (size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT; |
3308 | data_key_init(c, &from_key, inode->i_ino, block); |
3309 | highest_data_key(c, &to_key, inode->i_ino); |
3310 | |
3311 | mutex_lock(&c->tnc_mutex); |
3312 | err = ubifs_lookup_level0(c, &from_key, &znode, &n); |
3313 | if (err < 0) |
3314 | goto out_unlock; |
3315 | |
3316 | if (err) { |
3317 | err = -EINVAL; |
3318 | key = &from_key; |
3319 | goto out_dump; |
3320 | } |
3321 | |
3322 | err = tnc_next(c, &znode, &n); |
3323 | if (err == -ENOENT) { |
3324 | err = 0; |
3325 | goto out_unlock; |
3326 | } |
3327 | if (err < 0) |
3328 | goto out_unlock; |
3329 | |
3330 | ubifs_assert(err == 0); |
3331 | key = &znode->zbranch[n].key; |
3332 | if (!key_in_range(c, key, &from_key, &to_key)) |
3333 | goto out_unlock; |
3334 | |
3335 | out_dump: |
3336 | block = key_block(c, key); |
3337 | ubifs_err("inode %lu has size %lld, but there are data at offset %lld " |
3338 | "(data key %s)", (unsigned long)inode->i_ino, size, |
3339 | ((loff_t)block) << UBIFS_BLOCK_SHIFT, DBGKEY(key)); |
3340 | dbg_dump_inode(c, inode); |
3341 | dbg_dump_stack(); |
3342 | err = -EINVAL; |
3343 | |
3344 | out_unlock: |
3345 | mutex_unlock(&c->tnc_mutex); |
3346 | return err; |
3347 | } |
3348 | |
3349 | #endif /* CONFIG_UBIFS_FS_DEBUG */ |
3350 |
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