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Artem Bityutskiy1e517642008-07-14 19:08:37 +03001/*
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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090034#include <linux/slab.h>
Artem Bityutskiy1e517642008-07-14 19:08:37 +030035#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 */
47enum {
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 */
77static 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 {
Sheng Yong235c3622015-03-20 10:39:42 +0000101 ubifs_err(c, "old idx added twice!");
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300102 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 */
118int 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 */
140static 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 */
179void destroy_old_idx(struct ubifs_info *c)
180{
Cody P Schaferbb25e492014-01-23 15:56:08 -0800181 struct ubifs_old_idx *old_idx, *n;
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300182
Cody P Schaferbb25e492014-01-23 15:56:08 -0800183 rbtree_postorder_for_each_entry_safe(old_idx, n, &c->old_idx, rb)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300184 kfree(old_idx);
Cody P Schaferbb25e492014-01-23 15:56:08 -0800185
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300186 c->old_idx = RB_ROOT;
187}
188
189/**
190 * copy_znode - copy a dirty znode.
191 * @c: UBIFS file-system description object
192 * @znode: znode to copy
193 *
194 * A dirty znode being committed may not be changed, so it is copied.
195 */
196static struct ubifs_znode *copy_znode(struct ubifs_info *c,
197 struct ubifs_znode *znode)
198{
199 struct ubifs_znode *zn;
200
Andrzej Hajdabbc8a0042015-08-07 09:59:31 +0200201 zn = kmemdup(znode, c->max_znode_sz, GFP_NOFS);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300202 if (unlikely(!zn))
203 return ERR_PTR(-ENOMEM);
204
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300205 zn->cnext = NULL;
206 __set_bit(DIRTY_ZNODE, &zn->flags);
207 __clear_bit(COW_ZNODE, &zn->flags);
208
Artem Bityutskiyf42eed72011-05-30 14:45:30 +0300209 ubifs_assert(!ubifs_zn_obsolete(znode));
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300210 __set_bit(OBSOLETE_ZNODE, &znode->flags);
211
212 if (znode->level != 0) {
213 int i;
214 const int n = zn->child_cnt;
215
216 /* The children now have new parent */
217 for (i = 0; i < n; i++) {
218 struct ubifs_zbranch *zbr = &zn->zbranch[i];
219
220 if (zbr->znode)
221 zbr->znode->parent = zn;
222 }
223 }
224
225 atomic_long_inc(&c->dirty_zn_cnt);
226 return zn;
227}
228
229/**
230 * add_idx_dirt - add dirt due to a dirty znode.
231 * @c: UBIFS file-system description object
232 * @lnum: LEB number of index node
233 * @dirt: size of index node
234 *
235 * This function updates lprops dirty space and the new size of the index.
236 */
237static int add_idx_dirt(struct ubifs_info *c, int lnum, int dirt)
238{
239 c->calc_idx_sz -= ALIGN(dirt, 8);
240 return ubifs_add_dirt(c, lnum, dirt);
241}
242
243/**
244 * dirty_cow_znode - ensure a znode is not being committed.
245 * @c: UBIFS file-system description object
246 * @zbr: branch of znode to check
247 *
248 * Returns dirtied znode on success or negative error code on failure.
249 */
250static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c,
251 struct ubifs_zbranch *zbr)
252{
253 struct ubifs_znode *znode = zbr->znode;
254 struct ubifs_znode *zn;
255 int err;
256
Artem Bityutskiyf42eed72011-05-30 14:45:30 +0300257 if (!ubifs_zn_cow(znode)) {
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300258 /* znode is not being committed */
259 if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) {
260 atomic_long_inc(&c->dirty_zn_cnt);
261 atomic_long_dec(&c->clean_zn_cnt);
262 atomic_long_dec(&ubifs_clean_zn_cnt);
263 err = add_idx_dirt(c, zbr->lnum, zbr->len);
264 if (unlikely(err))
265 return ERR_PTR(err);
266 }
267 return znode;
268 }
269
270 zn = copy_znode(c, znode);
Hirofumi Nakagawa8d47aef2008-08-21 17:16:40 +0300271 if (IS_ERR(zn))
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300272 return zn;
273
274 if (zbr->len) {
275 err = insert_old_idx(c, zbr->lnum, zbr->offs);
276 if (unlikely(err))
277 return ERR_PTR(err);
278 err = add_idx_dirt(c, zbr->lnum, zbr->len);
279 } else
280 err = 0;
281
282 zbr->znode = zn;
283 zbr->lnum = 0;
284 zbr->offs = 0;
285 zbr->len = 0;
286
287 if (unlikely(err))
288 return ERR_PTR(err);
289 return zn;
290}
291
292/**
293 * lnc_add - add a leaf node to the leaf node cache.
294 * @c: UBIFS file-system description object
295 * @zbr: zbranch of leaf node
296 * @node: leaf node
297 *
298 * Leaf nodes are non-index nodes directory entry nodes or data nodes. The
299 * purpose of the leaf node cache is to save re-reading the same leaf node over
300 * and over again. Most things are cached by VFS, however the file system must
301 * cache directory entries for readdir and for resolving hash collisions. The
302 * present implementation of the leaf node cache is extremely simple, and
303 * allows for error returns that are not used but that may be needed if a more
304 * complex implementation is created.
305 *
306 * Note, this function does not add the @node object to LNC directly, but
307 * allocates a copy of the object and adds the copy to LNC. The reason for this
308 * is that @node has been allocated outside of the TNC subsystem and will be
309 * used with @c->tnc_mutex unlock upon return from the TNC subsystem. But LNC
310 * may be changed at any time, e.g. freed by the shrinker.
311 */
312static int lnc_add(struct ubifs_info *c, struct ubifs_zbranch *zbr,
313 const void *node)
314{
315 int err;
316 void *lnc_node;
317 const struct ubifs_dent_node *dent = node;
318
319 ubifs_assert(!zbr->leaf);
320 ubifs_assert(zbr->len != 0);
321 ubifs_assert(is_hash_key(c, &zbr->key));
322
323 err = ubifs_validate_entry(c, dent);
324 if (err) {
Artem Bityutskiy7c46d0a2012-05-16 19:04:54 +0300325 dump_stack();
Artem Bityutskiyedf6be22012-05-16 19:15:56 +0300326 ubifs_dump_node(c, dent);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300327 return err;
328 }
329
Thomas Meyereaecf432011-11-18 00:00:52 +0100330 lnc_node = kmemdup(node, zbr->len, GFP_NOFS);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300331 if (!lnc_node)
332 /* We don't have to have the cache, so no error */
333 return 0;
334
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300335 zbr->leaf = lnc_node;
336 return 0;
337}
338
339 /**
340 * lnc_add_directly - add a leaf node to the leaf-node-cache.
341 * @c: UBIFS file-system description object
342 * @zbr: zbranch of leaf node
343 * @node: leaf node
344 *
345 * This function is similar to 'lnc_add()', but it does not create a copy of
346 * @node but inserts @node to TNC directly.
347 */
348static int lnc_add_directly(struct ubifs_info *c, struct ubifs_zbranch *zbr,
349 void *node)
350{
351 int err;
352
353 ubifs_assert(!zbr->leaf);
354 ubifs_assert(zbr->len != 0);
355
356 err = ubifs_validate_entry(c, node);
357 if (err) {
Artem Bityutskiy7c46d0a2012-05-16 19:04:54 +0300358 dump_stack();
Artem Bityutskiyedf6be22012-05-16 19:15:56 +0300359 ubifs_dump_node(c, node);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300360 return err;
361 }
362
363 zbr->leaf = node;
364 return 0;
365}
366
367/**
368 * lnc_free - remove a leaf node from the leaf node cache.
369 * @zbr: zbranch of leaf node
370 * @node: leaf node
371 */
372static void lnc_free(struct ubifs_zbranch *zbr)
373{
374 if (!zbr->leaf)
375 return;
376 kfree(zbr->leaf);
377 zbr->leaf = NULL;
378}
379
380/**
381 * tnc_read_node_nm - read a "hashed" leaf node.
382 * @c: UBIFS file-system description object
383 * @zbr: key and position of the node
384 * @node: node is returned here
385 *
386 * This function reads a "hashed" node defined by @zbr from the leaf node cache
387 * (in it is there) or from the hash media, in which case the node is also
388 * added to LNC. Returns zero in case of success or a negative negative error
389 * code in case of failure.
390 */
391static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr,
392 void *node)
393{
394 int err;
395
396 ubifs_assert(is_hash_key(c, &zbr->key));
397
398 if (zbr->leaf) {
399 /* Read from the leaf node cache */
400 ubifs_assert(zbr->len != 0);
401 memcpy(node, zbr->leaf, zbr->len);
402 return 0;
403 }
404
405 err = ubifs_tnc_read_node(c, zbr, node);
406 if (err)
407 return err;
408
409 /* Add the node to the leaf node cache */
410 err = lnc_add(c, zbr, node);
411 return err;
412}
413
414/**
415 * try_read_node - read a node if it is a node.
416 * @c: UBIFS file-system description object
417 * @buf: buffer to read to
418 * @type: node type
419 * @len: node length (not aligned)
420 * @lnum: LEB number of node to read
421 * @offs: offset of node to read
422 *
423 * This function tries to read a node of known type and length, checks it and
424 * stores it in @buf. This function returns %1 if a node is present and %0 if
425 * a node is not present. A negative error code is returned for I/O errors.
426 * This function performs that same function as ubifs_read_node except that
427 * it does not require that there is actually a node present and instead
428 * the return code indicates if a node was read.
Artem Bityutskiy6f7ab6d2009-01-27 16:12:31 +0200429 *
430 * Note, this function does not check CRC of data nodes if @c->no_chk_data_crc
431 * is true (it is controlled by corresponding mount option). However, if
Artem Bityutskiy18d1d7f2011-01-17 22:27:56 +0200432 * @c->mounting or @c->remounting_rw is true (we are mounting or re-mounting to
433 * R/W mode), @c->no_chk_data_crc is ignored and CRC is checked. This is
434 * because during mounting or re-mounting from R/O mode to R/W mode we may read
435 * journal nodes (when replying the journal or doing the recovery) and the
436 * journal nodes may potentially be corrupted, so checking is required.
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300437 */
438static int try_read_node(const struct ubifs_info *c, void *buf, int type,
439 int len, int lnum, int offs)
440{
441 int err, node_len;
442 struct ubifs_ch *ch = buf;
443 uint32_t crc, node_crc;
444
445 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
446
Artem Bityutskiyd3048202011-06-03 14:03:25 +0300447 err = ubifs_leb_read(c, lnum, buf, offs, len, 1);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300448 if (err) {
Sheng Yong235c3622015-03-20 10:39:42 +0000449 ubifs_err(c, "cannot read node type %d from LEB %d:%d, error %d",
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300450 type, lnum, offs, err);
451 return err;
452 }
453
454 if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC)
455 return 0;
456
457 if (ch->node_type != type)
458 return 0;
459
460 node_len = le32_to_cpu(ch->len);
461 if (node_len != len)
462 return 0;
463
Artem Bityutskiy18d1d7f2011-01-17 22:27:56 +0200464 if (type == UBIFS_DATA_NODE && c->no_chk_data_crc && !c->mounting &&
465 !c->remounting_rw)
Artem Bityutskiy6f7ab6d2009-01-27 16:12:31 +0200466 return 1;
Adrian Hunter2953e732008-09-04 16:26:00 +0300467
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300468 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
469 node_crc = le32_to_cpu(ch->crc);
470 if (crc != node_crc)
471 return 0;
472
473 return 1;
474}
475
476/**
477 * fallible_read_node - try to read a leaf node.
478 * @c: UBIFS file-system description object
479 * @key: key of node to read
480 * @zbr: position of node
481 * @node: node returned
482 *
483 * This function tries to read a node and returns %1 if the node is read, %0
484 * if the node is not present, and a negative error code in the case of error.
485 */
486static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
487 struct ubifs_zbranch *zbr, void *node)
488{
489 int ret;
490
Artem Bityutskiy515315a2012-01-13 12:33:53 +0200491 dbg_tnck(key, "LEB %d:%d, key ", zbr->lnum, zbr->offs);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300492
493 ret = try_read_node(c, node, key_type(c, key), zbr->len, zbr->lnum,
494 zbr->offs);
495 if (ret == 1) {
496 union ubifs_key node_key;
497 struct ubifs_dent_node *dent = node;
498
499 /* All nodes have key in the same place */
500 key_read(c, &dent->key, &node_key);
501 if (keys_cmp(c, key, &node_key) != 0)
502 ret = 0;
503 }
Adrian Hunter601c0bc2008-08-22 14:23:35 +0300504 if (ret == 0 && c->replaying)
Artem Bityutskiy515315a2012-01-13 12:33:53 +0200505 dbg_mntk(key, "dangling branch LEB %d:%d len %d, key ",
506 zbr->lnum, zbr->offs, zbr->len);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300507 return ret;
508}
509
510/**
511 * matches_name - determine if a direntry or xattr entry matches a given name.
512 * @c: UBIFS file-system description object
513 * @zbr: zbranch of dent
514 * @nm: name to match
515 *
516 * This function checks if xentry/direntry referred by zbranch @zbr matches name
517 * @nm. Returns %NAME_MATCHES if it does, %NAME_LESS if the name referred by
518 * @zbr is less than @nm, and %NAME_GREATER if it is greater than @nm. In case
519 * of failure, a negative error code is returned.
520 */
521static int matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr,
522 const struct qstr *nm)
523{
524 struct ubifs_dent_node *dent;
525 int nlen, err;
526
527 /* If possible, match against the dent in the leaf node cache */
528 if (!zbr->leaf) {
529 dent = kmalloc(zbr->len, GFP_NOFS);
530 if (!dent)
531 return -ENOMEM;
532
533 err = ubifs_tnc_read_node(c, zbr, dent);
534 if (err)
535 goto out_free;
536
537 /* Add the node to the leaf node cache */
538 err = lnc_add_directly(c, zbr, dent);
539 if (err)
540 goto out_free;
541 } else
542 dent = zbr->leaf;
543
544 nlen = le16_to_cpu(dent->nlen);
545 err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
546 if (err == 0) {
547 if (nlen == nm->len)
548 return NAME_MATCHES;
549 else if (nlen < nm->len)
550 return NAME_LESS;
551 else
552 return NAME_GREATER;
553 } else if (err < 0)
554 return NAME_LESS;
555 else
556 return NAME_GREATER;
557
558out_free:
559 kfree(dent);
560 return err;
561}
562
563/**
564 * get_znode - get a TNC znode that may not be loaded yet.
565 * @c: UBIFS file-system description object
566 * @znode: parent znode
567 * @n: znode branch slot number
568 *
569 * This function returns the znode or a negative error code.
570 */
571static struct ubifs_znode *get_znode(struct ubifs_info *c,
572 struct ubifs_znode *znode, int n)
573{
574 struct ubifs_zbranch *zbr;
575
576 zbr = &znode->zbranch[n];
577 if (zbr->znode)
578 znode = zbr->znode;
579 else
580 znode = ubifs_load_znode(c, zbr, znode, n);
581 return znode;
582}
583
584/**
585 * tnc_next - find next TNC entry.
586 * @c: UBIFS file-system description object
587 * @zn: znode is passed and returned here
588 * @n: znode branch slot number is passed and returned here
589 *
590 * This function returns %0 if the next TNC entry is found, %-ENOENT if there is
591 * no next entry, or a negative error code otherwise.
592 */
593static int tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
594{
595 struct ubifs_znode *znode = *zn;
596 int nn = *n;
597
598 nn += 1;
599 if (nn < znode->child_cnt) {
600 *n = nn;
601 return 0;
602 }
603 while (1) {
604 struct ubifs_znode *zp;
605
606 zp = znode->parent;
607 if (!zp)
608 return -ENOENT;
609 nn = znode->iip + 1;
610 znode = zp;
611 if (nn < znode->child_cnt) {
612 znode = get_znode(c, znode, nn);
613 if (IS_ERR(znode))
614 return PTR_ERR(znode);
615 while (znode->level != 0) {
616 znode = get_znode(c, znode, 0);
617 if (IS_ERR(znode))
618 return PTR_ERR(znode);
619 }
620 nn = 0;
621 break;
622 }
623 }
624 *zn = znode;
625 *n = nn;
626 return 0;
627}
628
629/**
630 * tnc_prev - find previous TNC entry.
631 * @c: UBIFS file-system description object
632 * @zn: znode is returned here
633 * @n: znode branch slot number is passed and returned here
634 *
635 * This function returns %0 if the previous TNC entry is found, %-ENOENT if
636 * there is no next entry, or a negative error code otherwise.
637 */
638static int tnc_prev(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
639{
640 struct ubifs_znode *znode = *zn;
641 int nn = *n;
642
643 if (nn > 0) {
644 *n = nn - 1;
645 return 0;
646 }
647 while (1) {
648 struct ubifs_znode *zp;
649
650 zp = znode->parent;
651 if (!zp)
652 return -ENOENT;
653 nn = znode->iip - 1;
654 znode = zp;
655 if (nn >= 0) {
656 znode = get_znode(c, znode, nn);
657 if (IS_ERR(znode))
658 return PTR_ERR(znode);
659 while (znode->level != 0) {
660 nn = znode->child_cnt - 1;
661 znode = get_znode(c, znode, nn);
662 if (IS_ERR(znode))
663 return PTR_ERR(znode);
664 }
665 nn = znode->child_cnt - 1;
666 break;
667 }
668 }
669 *zn = znode;
670 *n = nn;
671 return 0;
672}
673
674/**
675 * resolve_collision - resolve a collision.
676 * @c: UBIFS file-system description object
677 * @key: key of a directory or extended attribute entry
678 * @zn: znode is returned here
679 * @n: zbranch number is passed and returned here
680 * @nm: name of the entry
681 *
682 * This function is called for "hashed" keys to make sure that the found key
683 * really corresponds to the looked up node (directory or extended attribute
684 * entry). It returns %1 and sets @zn and @n if the collision is resolved.
685 * %0 is returned if @nm is not found and @zn and @n are set to the previous
686 * entry, i.e. to the entry after which @nm could follow if it were in TNC.
687 * This means that @n may be set to %-1 if the leftmost key in @zn is the
688 * previous one. A negative error code is returned on failures.
689 */
690static int resolve_collision(struct ubifs_info *c, const union ubifs_key *key,
691 struct ubifs_znode **zn, int *n,
692 const struct qstr *nm)
693{
694 int err;
695
696 err = matches_name(c, &(*zn)->zbranch[*n], nm);
697 if (unlikely(err < 0))
698 return err;
699 if (err == NAME_MATCHES)
700 return 1;
701
702 if (err == NAME_GREATER) {
703 /* Look left */
704 while (1) {
705 err = tnc_prev(c, zn, n);
706 if (err == -ENOENT) {
707 ubifs_assert(*n == 0);
708 *n = -1;
709 return 0;
710 }
711 if (err < 0)
712 return err;
713 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
714 /*
715 * We have found the branch after which we would
716 * like to insert, but inserting in this znode
717 * may still be wrong. Consider the following 3
718 * znodes, in the case where we are resolving a
719 * collision with Key2.
720 *
721 * znode zp
722 * ----------------------
723 * level 1 | Key0 | Key1 |
724 * -----------------------
725 * | |
726 * znode za | | znode zb
727 * ------------ ------------
728 * level 0 | Key0 | | Key2 |
729 * ------------ ------------
730 *
731 * The lookup finds Key2 in znode zb. Lets say
732 * there is no match and the name is greater so
733 * we look left. When we find Key0, we end up
734 * here. If we return now, we will insert into
735 * znode za at slot n = 1. But that is invalid
736 * according to the parent's keys. Key2 must
737 * be inserted into znode zb.
738 *
739 * Note, this problem is not relevant for the
740 * case when we go right, because
741 * 'tnc_insert()' would correct the parent key.
742 */
743 if (*n == (*zn)->child_cnt - 1) {
744 err = tnc_next(c, zn, n);
745 if (err) {
746 /* Should be impossible */
747 ubifs_assert(0);
748 if (err == -ENOENT)
749 err = -EINVAL;
750 return err;
751 }
752 ubifs_assert(*n == 0);
753 *n = -1;
754 }
755 return 0;
756 }
757 err = matches_name(c, &(*zn)->zbranch[*n], nm);
758 if (err < 0)
759 return err;
760 if (err == NAME_LESS)
761 return 0;
762 if (err == NAME_MATCHES)
763 return 1;
764 ubifs_assert(err == NAME_GREATER);
765 }
766 } else {
767 int nn = *n;
768 struct ubifs_znode *znode = *zn;
769
770 /* Look right */
771 while (1) {
772 err = tnc_next(c, &znode, &nn);
773 if (err == -ENOENT)
774 return 0;
775 if (err < 0)
776 return err;
777 if (keys_cmp(c, &znode->zbranch[nn].key, key))
778 return 0;
779 err = matches_name(c, &znode->zbranch[nn], nm);
780 if (err < 0)
781 return err;
782 if (err == NAME_GREATER)
783 return 0;
784 *zn = znode;
785 *n = nn;
786 if (err == NAME_MATCHES)
787 return 1;
788 ubifs_assert(err == NAME_LESS);
789 }
790 }
791}
792
793/**
794 * fallible_matches_name - determine if a dent matches a given name.
795 * @c: UBIFS file-system description object
796 * @zbr: zbranch of dent
797 * @nm: name to match
798 *
799 * This is a "fallible" version of 'matches_name()' function which does not
800 * panic if the direntry/xentry referred by @zbr does not exist on the media.
801 *
802 * This function checks if xentry/direntry referred by zbranch @zbr matches name
803 * @nm. Returns %NAME_MATCHES it does, %NAME_LESS if the name referred by @zbr
804 * is less than @nm, %NAME_GREATER if it is greater than @nm, and @NOT_ON_MEDIA
805 * if xentry/direntry referred by @zbr does not exist on the media. A negative
806 * error code is returned in case of failure.
807 */
808static int fallible_matches_name(struct ubifs_info *c,
809 struct ubifs_zbranch *zbr,
810 const struct qstr *nm)
811{
812 struct ubifs_dent_node *dent;
813 int nlen, err;
814
815 /* If possible, match against the dent in the leaf node cache */
816 if (!zbr->leaf) {
817 dent = kmalloc(zbr->len, GFP_NOFS);
818 if (!dent)
819 return -ENOMEM;
820
821 err = fallible_read_node(c, &zbr->key, zbr, dent);
822 if (err < 0)
823 goto out_free;
824 if (err == 0) {
825 /* The node was not present */
826 err = NOT_ON_MEDIA;
827 goto out_free;
828 }
829 ubifs_assert(err == 1);
830
831 err = lnc_add_directly(c, zbr, dent);
832 if (err)
833 goto out_free;
834 } else
835 dent = zbr->leaf;
836
837 nlen = le16_to_cpu(dent->nlen);
838 err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
839 if (err == 0) {
840 if (nlen == nm->len)
841 return NAME_MATCHES;
842 else if (nlen < nm->len)
843 return NAME_LESS;
844 else
845 return NAME_GREATER;
846 } else if (err < 0)
847 return NAME_LESS;
848 else
849 return NAME_GREATER;
850
851out_free:
852 kfree(dent);
853 return err;
854}
855
856/**
857 * fallible_resolve_collision - resolve a collision even if nodes are missing.
858 * @c: UBIFS file-system description object
859 * @key: key
860 * @zn: znode is returned here
861 * @n: branch number is passed and returned here
862 * @nm: name of directory entry
863 * @adding: indicates caller is adding a key to the TNC
864 *
865 * This is a "fallible" version of the 'resolve_collision()' function which
866 * does not panic if one of the nodes referred to by TNC does not exist on the
867 * media. This may happen when replaying the journal if a deleted node was
868 * Garbage-collected and the commit was not done. A branch that refers to a node
869 * that is not present is called a dangling branch. The following are the return
870 * codes for this function:
871 * o if @nm was found, %1 is returned and @zn and @n are set to the found
872 * branch;
873 * o if we are @adding and @nm was not found, %0 is returned;
874 * o if we are not @adding and @nm was not found, but a dangling branch was
875 * found, then %1 is returned and @zn and @n are set to the dangling branch;
876 * o a negative error code is returned in case of failure.
877 */
878static int fallible_resolve_collision(struct ubifs_info *c,
879 const union ubifs_key *key,
880 struct ubifs_znode **zn, int *n,
881 const struct qstr *nm, int adding)
882{
883 struct ubifs_znode *o_znode = NULL, *znode = *zn;
884 int uninitialized_var(o_n), err, cmp, unsure = 0, nn = *n;
885
886 cmp = fallible_matches_name(c, &znode->zbranch[nn], nm);
887 if (unlikely(cmp < 0))
888 return cmp;
889 if (cmp == NAME_MATCHES)
890 return 1;
891 if (cmp == NOT_ON_MEDIA) {
892 o_znode = znode;
893 o_n = nn;
894 /*
895 * We are unlucky and hit a dangling branch straight away.
896 * Now we do not really know where to go to find the needed
897 * branch - to the left or to the right. Well, let's try left.
898 */
899 unsure = 1;
900 } else if (!adding)
901 unsure = 1; /* Remove a dangling branch wherever it is */
902
903 if (cmp == NAME_GREATER || unsure) {
904 /* Look left */
905 while (1) {
906 err = tnc_prev(c, zn, n);
907 if (err == -ENOENT) {
908 ubifs_assert(*n == 0);
909 *n = -1;
910 break;
911 }
912 if (err < 0)
913 return err;
914 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
915 /* See comments in 'resolve_collision()' */
916 if (*n == (*zn)->child_cnt - 1) {
917 err = tnc_next(c, zn, n);
918 if (err) {
919 /* Should be impossible */
920 ubifs_assert(0);
921 if (err == -ENOENT)
922 err = -EINVAL;
923 return err;
924 }
925 ubifs_assert(*n == 0);
926 *n = -1;
927 }
928 break;
929 }
930 err = fallible_matches_name(c, &(*zn)->zbranch[*n], nm);
931 if (err < 0)
932 return err;
933 if (err == NAME_MATCHES)
934 return 1;
935 if (err == NOT_ON_MEDIA) {
936 o_znode = *zn;
937 o_n = *n;
938 continue;
939 }
940 if (!adding)
941 continue;
942 if (err == NAME_LESS)
943 break;
944 else
945 unsure = 0;
946 }
947 }
948
949 if (cmp == NAME_LESS || unsure) {
950 /* Look right */
951 *zn = znode;
952 *n = nn;
953 while (1) {
954 err = tnc_next(c, &znode, &nn);
955 if (err == -ENOENT)
956 break;
957 if (err < 0)
958 return err;
959 if (keys_cmp(c, &znode->zbranch[nn].key, key))
960 break;
961 err = fallible_matches_name(c, &znode->zbranch[nn], nm);
962 if (err < 0)
963 return err;
964 if (err == NAME_GREATER)
965 break;
966 *zn = znode;
967 *n = nn;
968 if (err == NAME_MATCHES)
969 return 1;
970 if (err == NOT_ON_MEDIA) {
971 o_znode = znode;
972 o_n = nn;
973 }
974 }
975 }
976
977 /* Never match a dangling branch when adding */
978 if (adding || !o_znode)
979 return 0;
980
Artem Bityutskiy515315a2012-01-13 12:33:53 +0200981 dbg_mntk(key, "dangling match LEB %d:%d len %d key ",
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300982 o_znode->zbranch[o_n].lnum, o_znode->zbranch[o_n].offs,
Artem Bityutskiy515315a2012-01-13 12:33:53 +0200983 o_znode->zbranch[o_n].len);
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300984 *zn = o_znode;
985 *n = o_n;
986 return 1;
987}
988
989/**
990 * matches_position - determine if a zbranch matches a given position.
991 * @zbr: zbranch of dent
992 * @lnum: LEB number of dent to match
993 * @offs: offset of dent to match
994 *
995 * This function returns %1 if @lnum:@offs matches, and %0 otherwise.
996 */
997static int matches_position(struct ubifs_zbranch *zbr, int lnum, int offs)
998{
999 if (zbr->lnum == lnum && zbr->offs == offs)
1000 return 1;
1001 else
1002 return 0;
1003}
1004
1005/**
1006 * resolve_collision_directly - resolve a collision directly.
1007 * @c: UBIFS file-system description object
1008 * @key: key of directory entry
1009 * @zn: znode is passed and returned here
1010 * @n: zbranch number is passed and returned here
1011 * @lnum: LEB number of dent node to match
1012 * @offs: offset of dent node to match
1013 *
1014 * This function is used for "hashed" keys to make sure the found directory or
1015 * extended attribute entry node is what was looked for. It is used when the
1016 * flash address of the right node is known (@lnum:@offs) which makes it much
1017 * easier to resolve collisions (no need to read entries and match full
1018 * names). This function returns %1 and sets @zn and @n if the collision is
1019 * resolved, %0 if @lnum:@offs is not found and @zn and @n are set to the
1020 * previous directory entry. Otherwise a negative error code is returned.
1021 */
1022static int resolve_collision_directly(struct ubifs_info *c,
1023 const union ubifs_key *key,
1024 struct ubifs_znode **zn, int *n,
1025 int lnum, int offs)
1026{
1027 struct ubifs_znode *znode;
1028 int nn, err;
1029
1030 znode = *zn;
1031 nn = *n;
1032 if (matches_position(&znode->zbranch[nn], lnum, offs))
1033 return 1;
1034
1035 /* Look left */
1036 while (1) {
1037 err = tnc_prev(c, &znode, &nn);
1038 if (err == -ENOENT)
1039 break;
1040 if (err < 0)
1041 return err;
1042 if (keys_cmp(c, &znode->zbranch[nn].key, key))
1043 break;
1044 if (matches_position(&znode->zbranch[nn], lnum, offs)) {
1045 *zn = znode;
1046 *n = nn;
1047 return 1;
1048 }
1049 }
1050
1051 /* Look right */
1052 znode = *zn;
1053 nn = *n;
1054 while (1) {
1055 err = tnc_next(c, &znode, &nn);
1056 if (err == -ENOENT)
1057 return 0;
1058 if (err < 0)
1059 return err;
1060 if (keys_cmp(c, &znode->zbranch[nn].key, key))
1061 return 0;
1062 *zn = znode;
1063 *n = nn;
1064 if (matches_position(&znode->zbranch[nn], lnum, offs))
1065 return 1;
1066 }
1067}
1068
1069/**
1070 * dirty_cow_bottom_up - dirty a znode and its ancestors.
1071 * @c: UBIFS file-system description object
1072 * @znode: znode to dirty
1073 *
1074 * If we do not have a unique key that resides in a znode, then we cannot
1075 * dirty that znode from the top down (i.e. by using lookup_level0_dirty)
1076 * This function records the path back to the last dirty ancestor, and then
1077 * dirties the znodes on that path.
1078 */
1079static struct ubifs_znode *dirty_cow_bottom_up(struct ubifs_info *c,
1080 struct ubifs_znode *znode)
1081{
1082 struct ubifs_znode *zp;
1083 int *path = c->bottom_up_buf, p = 0;
1084
1085 ubifs_assert(c->zroot.znode);
1086 ubifs_assert(znode);
1087 if (c->zroot.znode->level > BOTTOM_UP_HEIGHT) {
1088 kfree(c->bottom_up_buf);
1089 c->bottom_up_buf = kmalloc(c->zroot.znode->level * sizeof(int),
1090 GFP_NOFS);
1091 if (!c->bottom_up_buf)
1092 return ERR_PTR(-ENOMEM);
1093 path = c->bottom_up_buf;
1094 }
1095 if (c->zroot.znode->level) {
1096 /* Go up until parent is dirty */
1097 while (1) {
1098 int n;
1099
1100 zp = znode->parent;
1101 if (!zp)
1102 break;
1103 n = znode->iip;
1104 ubifs_assert(p < c->zroot.znode->level);
1105 path[p++] = n;
1106 if (!zp->cnext && ubifs_zn_dirty(znode))
1107 break;
1108 znode = zp;
1109 }
1110 }
1111
1112 /* Come back down, dirtying as we go */
1113 while (1) {
1114 struct ubifs_zbranch *zbr;
1115
1116 zp = znode->parent;
1117 if (zp) {
1118 ubifs_assert(path[p - 1] >= 0);
1119 ubifs_assert(path[p - 1] < zp->child_cnt);
1120 zbr = &zp->zbranch[path[--p]];
1121 znode = dirty_cow_znode(c, zbr);
1122 } else {
1123 ubifs_assert(znode == c->zroot.znode);
1124 znode = dirty_cow_znode(c, &c->zroot);
1125 }
Hirofumi Nakagawa8d47aef2008-08-21 17:16:40 +03001126 if (IS_ERR(znode) || !p)
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001127 break;
1128 ubifs_assert(path[p - 1] >= 0);
1129 ubifs_assert(path[p - 1] < znode->child_cnt);
1130 znode = znode->zbranch[path[p - 1]].znode;
1131 }
1132
1133 return znode;
1134}
1135
1136/**
1137 * ubifs_lookup_level0 - search for zero-level znode.
1138 * @c: UBIFS file-system description object
1139 * @key: key to lookup
1140 * @zn: znode is returned here
1141 * @n: znode branch slot number is returned here
1142 *
1143 * This function looks up the TNC tree and search for zero-level znode which
1144 * refers key @key. The found zero-level znode is returned in @zn. There are 3
1145 * cases:
1146 * o exact match, i.e. the found zero-level znode contains key @key, then %1
1147 * is returned and slot number of the matched branch is stored in @n;
1148 * o not exact match, which means that zero-level znode does not contain
Artem Bityutskiye3c3efc2009-08-27 16:34:19 +03001149 * @key, then %0 is returned and slot number of the closest branch is stored
1150 * in @n;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001151 * o @key is so small that it is even less than the lowest key of the
1152 * leftmost zero-level node, then %0 is returned and %0 is stored in @n.
1153 *
1154 * Note, when the TNC tree is traversed, some znodes may be absent, then this
1155 * function reads corresponding indexing nodes and inserts them to TNC. In
1156 * case of failure, a negative error code is returned.
1157 */
1158int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
1159 struct ubifs_znode **zn, int *n)
1160{
1161 int err, exact;
1162 struct ubifs_znode *znode;
1163 unsigned long time = get_seconds();
1164
Artem Bityutskiy515315a2012-01-13 12:33:53 +02001165 dbg_tnck(key, "search key ");
Artem Bityutskiyba2f48f2010-08-22 07:10:12 +03001166 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001167
1168 znode = c->zroot.znode;
1169 if (unlikely(!znode)) {
1170 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
1171 if (IS_ERR(znode))
1172 return PTR_ERR(znode);
1173 }
1174
1175 znode->time = time;
1176
1177 while (1) {
1178 struct ubifs_zbranch *zbr;
1179
1180 exact = ubifs_search_zbranch(c, znode, key, n);
1181
1182 if (znode->level == 0)
1183 break;
1184
1185 if (*n < 0)
1186 *n = 0;
1187 zbr = &znode->zbranch[*n];
1188
1189 if (zbr->znode) {
1190 znode->time = time;
1191 znode = zbr->znode;
1192 continue;
1193 }
1194
1195 /* znode is not in TNC cache, load it from the media */
1196 znode = ubifs_load_znode(c, zbr, znode, *n);
1197 if (IS_ERR(znode))
1198 return PTR_ERR(znode);
1199 }
1200
1201 *zn = znode;
1202 if (exact || !is_hash_key(c, key) || *n != -1) {
1203 dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
1204 return exact;
1205 }
1206
1207 /*
1208 * Here is a tricky place. We have not found the key and this is a
1209 * "hashed" key, which may collide. The rest of the code deals with
1210 * situations like this:
1211 *
1212 * | 3 | 5 |
1213 * / \
1214 * | 3 | 5 | | 6 | 7 | (x)
1215 *
1216 * Or more a complex example:
1217 *
1218 * | 1 | 5 |
1219 * / \
1220 * | 1 | 3 | | 5 | 8 |
1221 * \ /
1222 * | 5 | 5 | | 6 | 7 | (x)
1223 *
1224 * In the examples, if we are looking for key "5", we may reach nodes
1225 * marked with "(x)". In this case what we have do is to look at the
1226 * left and see if there is "5" key there. If there is, we have to
1227 * return it.
1228 *
1229 * Note, this whole situation is possible because we allow to have
1230 * elements which are equivalent to the next key in the parent in the
1231 * children of current znode. For example, this happens if we split a
1232 * znode like this: | 3 | 5 | 5 | 6 | 7 |, which results in something
1233 * like this:
1234 * | 3 | 5 |
1235 * / \
1236 * | 3 | 5 | | 5 | 6 | 7 |
1237 * ^
1238 * And this becomes what is at the first "picture" after key "5" marked
1239 * with "^" is removed. What could be done is we could prohibit
1240 * splitting in the middle of the colliding sequence. Also, when
1241 * removing the leftmost key, we would have to correct the key of the
1242 * parent node, which would introduce additional complications. Namely,
Artem Bityutskiy7d4e9cc2009-03-20 19:11:12 +02001243 * if we changed the leftmost key of the parent znode, the garbage
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001244 * collector would be unable to find it (GC is doing this when GC'ing
1245 * indexing LEBs). Although we already have an additional RB-tree where
1246 * we save such changed znodes (see 'ins_clr_old_idx_znode()') until
1247 * after the commit. But anyway, this does not look easy to implement
1248 * so we did not try this.
1249 */
1250 err = tnc_prev(c, &znode, n);
1251 if (err == -ENOENT) {
1252 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1253 *n = -1;
1254 return 0;
1255 }
1256 if (unlikely(err < 0))
1257 return err;
1258 if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
1259 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1260 *n = -1;
1261 return 0;
1262 }
1263
1264 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1265 *zn = znode;
1266 return 1;
1267}
1268
1269/**
1270 * lookup_level0_dirty - search for zero-level znode dirtying.
1271 * @c: UBIFS file-system description object
1272 * @key: key to lookup
1273 * @zn: znode is returned here
1274 * @n: znode branch slot number is returned here
1275 *
1276 * This function looks up the TNC tree and search for zero-level znode which
1277 * refers key @key. The found zero-level znode is returned in @zn. There are 3
1278 * cases:
1279 * o exact match, i.e. the found zero-level znode contains key @key, then %1
1280 * is returned and slot number of the matched branch is stored in @n;
1281 * o not exact match, which means that zero-level znode does not contain @key
1282 * then %0 is returned and slot number of the closed branch is stored in
1283 * @n;
1284 * o @key is so small that it is even less than the lowest key of the
1285 * leftmost zero-level node, then %0 is returned and %-1 is stored in @n.
1286 *
1287 * Additionally all znodes in the path from the root to the located zero-level
1288 * znode are marked as dirty.
1289 *
1290 * Note, when the TNC tree is traversed, some znodes may be absent, then this
1291 * function reads corresponding indexing nodes and inserts them to TNC. In
1292 * case of failure, a negative error code is returned.
1293 */
1294static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key,
1295 struct ubifs_znode **zn, int *n)
1296{
1297 int err, exact;
1298 struct ubifs_znode *znode;
1299 unsigned long time = get_seconds();
1300
Artem Bityutskiy515315a2012-01-13 12:33:53 +02001301 dbg_tnck(key, "search and dirty key ");
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001302
1303 znode = c->zroot.znode;
1304 if (unlikely(!znode)) {
1305 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
1306 if (IS_ERR(znode))
1307 return PTR_ERR(znode);
1308 }
1309
1310 znode = dirty_cow_znode(c, &c->zroot);
1311 if (IS_ERR(znode))
1312 return PTR_ERR(znode);
1313
1314 znode->time = time;
1315
1316 while (1) {
1317 struct ubifs_zbranch *zbr;
1318
1319 exact = ubifs_search_zbranch(c, znode, key, n);
1320
1321 if (znode->level == 0)
1322 break;
1323
1324 if (*n < 0)
1325 *n = 0;
1326 zbr = &znode->zbranch[*n];
1327
1328 if (zbr->znode) {
1329 znode->time = time;
1330 znode = dirty_cow_znode(c, zbr);
1331 if (IS_ERR(znode))
1332 return PTR_ERR(znode);
1333 continue;
1334 }
1335
1336 /* znode is not in TNC cache, load it from the media */
1337 znode = ubifs_load_znode(c, zbr, znode, *n);
1338 if (IS_ERR(znode))
1339 return PTR_ERR(znode);
1340 znode = dirty_cow_znode(c, zbr);
1341 if (IS_ERR(znode))
1342 return PTR_ERR(znode);
1343 }
1344
1345 *zn = znode;
1346 if (exact || !is_hash_key(c, key) || *n != -1) {
1347 dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
1348 return exact;
1349 }
1350
1351 /*
1352 * See huge comment at 'lookup_level0_dirty()' what is the rest of the
1353 * code.
1354 */
1355 err = tnc_prev(c, &znode, n);
1356 if (err == -ENOENT) {
1357 *n = -1;
1358 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1359 return 0;
1360 }
1361 if (unlikely(err < 0))
1362 return err;
1363 if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
1364 *n = -1;
1365 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1366 return 0;
1367 }
1368
1369 if (znode->cnext || !ubifs_zn_dirty(znode)) {
1370 znode = dirty_cow_bottom_up(c, znode);
1371 if (IS_ERR(znode))
1372 return PTR_ERR(znode);
1373 }
1374
1375 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1376 *zn = znode;
1377 return 1;
1378}
1379
1380/**
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001381 * maybe_leb_gced - determine if a LEB may have been garbage collected.
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001382 * @c: UBIFS file-system description object
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001383 * @lnum: LEB number
1384 * @gc_seq1: garbage collection sequence number
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001385 *
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001386 * This function determines if @lnum may have been garbage collected since
1387 * sequence number @gc_seq1. If it may have been then %1 is returned, otherwise
1388 * %0 is returned.
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001389 */
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001390static int maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1)
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001391{
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001392 int gc_seq2, gced_lnum;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001393
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001394 gced_lnum = c->gced_lnum;
1395 smp_rmb();
1396 gc_seq2 = c->gc_seq;
1397 /* Same seq means no GC */
1398 if (gc_seq1 == gc_seq2)
1399 return 0;
1400 /* Different by more than 1 means we don't know */
1401 if (gc_seq1 + 1 != gc_seq2)
1402 return 1;
1403 /*
1404 * We have seen the sequence number has increased by 1. Now we need to
1405 * be sure we read the right LEB number, so read it again.
1406 */
1407 smp_rmb();
1408 if (gced_lnum != c->gced_lnum)
1409 return 1;
1410 /* Finally we can check lnum */
1411 if (gced_lnum == lnum)
1412 return 1;
1413 return 0;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001414}
1415
1416/**
1417 * ubifs_tnc_locate - look up a file-system node and return it and its location.
1418 * @c: UBIFS file-system description object
1419 * @key: node key to lookup
1420 * @node: the node is returned here
1421 * @lnum: LEB number is returned here
1422 * @offs: offset is returned here
1423 *
Artem Bityutskiye3c3efc2009-08-27 16:34:19 +03001424 * This function looks up and reads node with key @key. The caller has to make
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001425 * sure the @node buffer is large enough to fit the node. Returns zero in case
1426 * of success, %-ENOENT if the node was not found, and a negative error code in
1427 * case of failure. The node location can be returned in @lnum and @offs.
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001428 */
1429int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key,
1430 void *node, int *lnum, int *offs)
1431{
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001432 int found, n, err, safely = 0, gc_seq1;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001433 struct ubifs_znode *znode;
1434 struct ubifs_zbranch zbr, *zt;
1435
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001436again:
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001437 mutex_lock(&c->tnc_mutex);
1438 found = ubifs_lookup_level0(c, key, &znode, &n);
1439 if (!found) {
1440 err = -ENOENT;
1441 goto out;
1442 } else if (found < 0) {
1443 err = found;
1444 goto out;
1445 }
1446 zt = &znode->zbranch[n];
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001447 if (lnum) {
1448 *lnum = zt->lnum;
1449 *offs = zt->offs;
1450 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001451 if (is_hash_key(c, key)) {
1452 /*
1453 * In this case the leaf node cache gets used, so we pass the
1454 * address of the zbranch and keep the mutex locked
1455 */
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001456 err = tnc_read_node_nm(c, zt, node);
1457 goto out;
1458 }
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001459 if (safely) {
1460 err = ubifs_tnc_read_node(c, zt, node);
1461 goto out;
1462 }
1463 /* Drop the TNC mutex prematurely and race with garbage collection */
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001464 zbr = znode->zbranch[n];
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001465 gc_seq1 = c->gc_seq;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001466 mutex_unlock(&c->tnc_mutex);
1467
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001468 if (ubifs_get_wbuf(c, zbr.lnum)) {
1469 /* We do not GC journal heads */
1470 err = ubifs_tnc_read_node(c, &zbr, node);
1471 return err;
1472 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001473
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001474 err = fallible_read_node(c, key, &zbr, node);
Adrian Hunter6dcfac42008-09-12 12:27:47 +03001475 if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) {
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001476 /*
1477 * The node may have been GC'ed out from under us so try again
1478 * while keeping the TNC mutex locked.
1479 */
1480 safely = 1;
1481 goto again;
1482 }
1483 return 0;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001484
1485out:
1486 mutex_unlock(&c->tnc_mutex);
1487 return err;
1488}
1489
1490/**
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001491 * ubifs_tnc_get_bu_keys - lookup keys for bulk-read.
1492 * @c: UBIFS file-system description object
1493 * @bu: bulk-read parameters and results
1494 *
1495 * Lookup consecutive data node keys for the same inode that reside
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +02001496 * consecutively in the same LEB. This function returns zero in case of success
1497 * and a negative error code in case of failure.
1498 *
1499 * Note, if the bulk-read buffer length (@bu->buf_len) is known, this function
1500 * makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares
Artem Bityutskiy6f7ab6d2009-01-27 16:12:31 +02001501 * maximum possible amount of nodes for bulk-read.
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001502 */
1503int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)
1504{
1505 int n, err = 0, lnum = -1, uninitialized_var(offs);
1506 int uninitialized_var(len);
1507 unsigned int block = key_block(c, &bu->key);
1508 struct ubifs_znode *znode;
1509
1510 bu->cnt = 0;
1511 bu->blk_cnt = 0;
1512 bu->eof = 0;
1513
1514 mutex_lock(&c->tnc_mutex);
1515 /* Find first key */
1516 err = ubifs_lookup_level0(c, &bu->key, &znode, &n);
1517 if (err < 0)
1518 goto out;
1519 if (err) {
1520 /* Key found */
1521 len = znode->zbranch[n].len;
1522 /* The buffer must be big enough for at least 1 node */
1523 if (len > bu->buf_len) {
1524 err = -EINVAL;
1525 goto out;
1526 }
1527 /* Add this key */
1528 bu->zbranch[bu->cnt++] = znode->zbranch[n];
1529 bu->blk_cnt += 1;
1530 lnum = znode->zbranch[n].lnum;
1531 offs = ALIGN(znode->zbranch[n].offs + len, 8);
1532 }
1533 while (1) {
1534 struct ubifs_zbranch *zbr;
1535 union ubifs_key *key;
1536 unsigned int next_block;
1537
1538 /* Find next key */
1539 err = tnc_next(c, &znode, &n);
1540 if (err)
1541 goto out;
1542 zbr = &znode->zbranch[n];
1543 key = &zbr->key;
1544 /* See if there is another data key for this file */
1545 if (key_inum(c, key) != key_inum(c, &bu->key) ||
1546 key_type(c, key) != UBIFS_DATA_KEY) {
1547 err = -ENOENT;
1548 goto out;
1549 }
1550 if (lnum < 0) {
1551 /* First key found */
1552 lnum = zbr->lnum;
1553 offs = ALIGN(zbr->offs + zbr->len, 8);
1554 len = zbr->len;
1555 if (len > bu->buf_len) {
1556 err = -EINVAL;
1557 goto out;
1558 }
1559 } else {
1560 /*
1561 * The data nodes must be in consecutive positions in
1562 * the same LEB.
1563 */
1564 if (zbr->lnum != lnum || zbr->offs != offs)
1565 goto out;
1566 offs += ALIGN(zbr->len, 8);
1567 len = ALIGN(len, 8) + zbr->len;
1568 /* Must not exceed buffer length */
1569 if (len > bu->buf_len)
1570 goto out;
1571 }
1572 /* Allow for holes */
1573 next_block = key_block(c, key);
1574 bu->blk_cnt += (next_block - block - 1);
1575 if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
1576 goto out;
1577 block = next_block;
1578 /* Add this key */
1579 bu->zbranch[bu->cnt++] = *zbr;
1580 bu->blk_cnt += 1;
1581 /* See if we have room for more */
1582 if (bu->cnt >= UBIFS_MAX_BULK_READ)
1583 goto out;
1584 if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
1585 goto out;
1586 }
1587out:
1588 if (err == -ENOENT) {
1589 bu->eof = 1;
1590 err = 0;
1591 }
1592 bu->gc_seq = c->gc_seq;
1593 mutex_unlock(&c->tnc_mutex);
1594 if (err)
1595 return err;
1596 /*
1597 * An enormous hole could cause bulk-read to encompass too many
1598 * page cache pages, so limit the number here.
1599 */
Adrian Hunter63c300b2008-09-17 12:11:13 +03001600 if (bu->blk_cnt > UBIFS_MAX_BULK_READ)
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001601 bu->blk_cnt = UBIFS_MAX_BULK_READ;
1602 /*
1603 * Ensure that bulk-read covers a whole number of page cache
1604 * pages.
1605 */
1606 if (UBIFS_BLOCKS_PER_PAGE == 1 ||
1607 !(bu->blk_cnt & (UBIFS_BLOCKS_PER_PAGE - 1)))
1608 return 0;
1609 if (bu->eof) {
1610 /* At the end of file we can round up */
1611 bu->blk_cnt += UBIFS_BLOCKS_PER_PAGE - 1;
1612 return 0;
1613 }
1614 /* Exclude data nodes that do not make up a whole page cache page */
1615 block = key_block(c, &bu->key) + bu->blk_cnt;
1616 block &= ~(UBIFS_BLOCKS_PER_PAGE - 1);
1617 while (bu->cnt) {
1618 if (key_block(c, &bu->zbranch[bu->cnt - 1].key) < block)
1619 break;
1620 bu->cnt -= 1;
1621 }
1622 return 0;
1623}
1624
1625/**
1626 * read_wbuf - bulk-read from a LEB with a wbuf.
1627 * @wbuf: wbuf that may overlap the read
1628 * @buf: buffer into which to read
1629 * @len: read length
1630 * @lnum: LEB number from which to read
1631 * @offs: offset from which to read
1632 *
1633 * This functions returns %0 on success or a negative error code on failure.
1634 */
1635static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum,
1636 int offs)
1637{
1638 const struct ubifs_info *c = wbuf->c;
1639 int rlen, overlap;
1640
1641 dbg_io("LEB %d:%d, length %d", lnum, offs, len);
1642 ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
1643 ubifs_assert(!(offs & 7) && offs < c->leb_size);
1644 ubifs_assert(offs + len <= c->leb_size);
1645
1646 spin_lock(&wbuf->lock);
1647 overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
1648 if (!overlap) {
1649 /* We may safely unlock the write-buffer and read the data */
1650 spin_unlock(&wbuf->lock);
Artem Bityutskiyd3048202011-06-03 14:03:25 +03001651 return ubifs_leb_read(c, lnum, buf, offs, len, 0);
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001652 }
1653
1654 /* Don't read under wbuf */
1655 rlen = wbuf->offs - offs;
1656 if (rlen < 0)
1657 rlen = 0;
1658
1659 /* Copy the rest from the write-buffer */
1660 memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
1661 spin_unlock(&wbuf->lock);
1662
1663 if (rlen > 0)
1664 /* Read everything that goes before write-buffer */
Artem Bityutskiyd3048202011-06-03 14:03:25 +03001665 return ubifs_leb_read(c, lnum, buf, offs, rlen, 0);
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001666
1667 return 0;
1668}
1669
1670/**
1671 * validate_data_node - validate data nodes for bulk-read.
1672 * @c: UBIFS file-system description object
1673 * @buf: buffer containing data node to validate
1674 * @zbr: zbranch of data node to validate
1675 *
1676 * This functions returns %0 on success or a negative error code on failure.
1677 */
1678static int validate_data_node(struct ubifs_info *c, void *buf,
1679 struct ubifs_zbranch *zbr)
1680{
1681 union ubifs_key key1;
1682 struct ubifs_ch *ch = buf;
1683 int err, len;
1684
1685 if (ch->node_type != UBIFS_DATA_NODE) {
Sheng Yong235c3622015-03-20 10:39:42 +00001686 ubifs_err(c, "bad node type (%d but expected %d)",
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001687 ch->node_type, UBIFS_DATA_NODE);
1688 goto out_err;
1689 }
1690
Adrian Hunter2953e732008-09-04 16:26:00 +03001691 err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0, 0);
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001692 if (err) {
Sheng Yong235c3622015-03-20 10:39:42 +00001693 ubifs_err(c, "expected node type %d", UBIFS_DATA_NODE);
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001694 goto out;
1695 }
1696
1697 len = le32_to_cpu(ch->len);
1698 if (len != zbr->len) {
Sheng Yong235c3622015-03-20 10:39:42 +00001699 ubifs_err(c, "bad node length %d, expected %d", len, zbr->len);
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001700 goto out_err;
1701 }
1702
1703 /* Make sure the key of the read node is correct */
1704 key_read(c, buf + UBIFS_KEY_OFFSET, &key1);
1705 if (!keys_eq(c, &zbr->key, &key1)) {
Sheng Yong235c3622015-03-20 10:39:42 +00001706 ubifs_err(c, "bad key in node at LEB %d:%d",
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001707 zbr->lnum, zbr->offs);
Artem Bityutskiy515315a2012-01-13 12:33:53 +02001708 dbg_tnck(&zbr->key, "looked for key ");
1709 dbg_tnck(&key1, "found node's key ");
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001710 goto out_err;
1711 }
1712
1713 return 0;
1714
1715out_err:
1716 err = -EINVAL;
1717out:
Sheng Yong235c3622015-03-20 10:39:42 +00001718 ubifs_err(c, "bad node at LEB %d:%d", zbr->lnum, zbr->offs);
Artem Bityutskiyedf6be22012-05-16 19:15:56 +03001719 ubifs_dump_node(c, buf);
Artem Bityutskiy7c46d0a2012-05-16 19:04:54 +03001720 dump_stack();
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001721 return err;
1722}
1723
1724/**
1725 * ubifs_tnc_bulk_read - read a number of data nodes in one go.
1726 * @c: UBIFS file-system description object
1727 * @bu: bulk-read parameters and results
1728 *
1729 * This functions reads and validates the data nodes that were identified by the
1730 * 'ubifs_tnc_get_bu_keys()' function. This functions returns %0 on success,
1731 * -EAGAIN to indicate a race with GC, or another negative error code on
1732 * failure.
1733 */
1734int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu)
1735{
1736 int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i;
1737 struct ubifs_wbuf *wbuf;
1738 void *buf;
1739
1740 len = bu->zbranch[bu->cnt - 1].offs;
1741 len += bu->zbranch[bu->cnt - 1].len - offs;
1742 if (len > bu->buf_len) {
Sheng Yong235c3622015-03-20 10:39:42 +00001743 ubifs_err(c, "buffer too small %d vs %d", bu->buf_len, len);
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001744 return -EINVAL;
1745 }
1746
1747 /* Do the read */
1748 wbuf = ubifs_get_wbuf(c, lnum);
1749 if (wbuf)
1750 err = read_wbuf(wbuf, bu->buf, len, lnum, offs);
1751 else
Artem Bityutskiyd3048202011-06-03 14:03:25 +03001752 err = ubifs_leb_read(c, lnum, bu->buf, offs, len, 0);
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001753
1754 /* Check for a race with GC */
1755 if (maybe_leb_gced(c, lnum, bu->gc_seq))
1756 return -EAGAIN;
1757
1758 if (err && err != -EBADMSG) {
Sheng Yong235c3622015-03-20 10:39:42 +00001759 ubifs_err(c, "failed to read from LEB %d:%d, error %d",
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001760 lnum, offs, err);
Artem Bityutskiy7c46d0a2012-05-16 19:04:54 +03001761 dump_stack();
Artem Bityutskiy515315a2012-01-13 12:33:53 +02001762 dbg_tnck(&bu->key, "key ");
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001763 return err;
1764 }
1765
1766 /* Validate the nodes read */
1767 buf = bu->buf;
1768 for (i = 0; i < bu->cnt; i++) {
1769 err = validate_data_node(c, buf, &bu->zbranch[i]);
1770 if (err)
1771 return err;
1772 buf = buf + ALIGN(bu->zbranch[i].len, 8);
1773 }
1774
1775 return 0;
1776}
1777
1778/**
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001779 * do_lookup_nm- look up a "hashed" node.
1780 * @c: UBIFS file-system description object
1781 * @key: node key to lookup
1782 * @node: the node is returned here
1783 * @nm: node name
1784 *
1785 * This function look up and reads a node which contains name hash in the key.
1786 * Since the hash may have collisions, there may be many nodes with the same
1787 * key, so we have to sequentially look to all of them until the needed one is
1788 * found. This function returns zero in case of success, %-ENOENT if the node
1789 * was not found, and a negative error code in case of failure.
1790 */
1791static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1792 void *node, const struct qstr *nm)
1793{
1794 int found, n, err;
1795 struct ubifs_znode *znode;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001796
Artem Bityutskiy515315a2012-01-13 12:33:53 +02001797 dbg_tnck(key, "name '%.*s' key ", nm->len, nm->name);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001798 mutex_lock(&c->tnc_mutex);
1799 found = ubifs_lookup_level0(c, key, &znode, &n);
1800 if (!found) {
1801 err = -ENOENT;
1802 goto out_unlock;
1803 } else if (found < 0) {
1804 err = found;
1805 goto out_unlock;
1806 }
1807
1808 ubifs_assert(n >= 0);
1809
1810 err = resolve_collision(c, key, &znode, &n, nm);
1811 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
1812 if (unlikely(err < 0))
1813 goto out_unlock;
1814 if (err == 0) {
1815 err = -ENOENT;
1816 goto out_unlock;
1817 }
1818
Adrian Hunter761e29f2008-08-20 16:32:40 +03001819 err = tnc_read_node_nm(c, &znode->zbranch[n], node);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001820
1821out_unlock:
1822 mutex_unlock(&c->tnc_mutex);
1823 return err;
1824}
1825
1826/**
1827 * ubifs_tnc_lookup_nm - look up a "hashed" node.
1828 * @c: UBIFS file-system description object
1829 * @key: node key to lookup
1830 * @node: the node is returned here
1831 * @nm: node name
1832 *
1833 * This function look up and reads a node which contains name hash in the key.
1834 * Since the hash may have collisions, there may be many nodes with the same
1835 * key, so we have to sequentially look to all of them until the needed one is
1836 * found. This function returns zero in case of success, %-ENOENT if the node
1837 * was not found, and a negative error code in case of failure.
1838 */
1839int ubifs_tnc_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1840 void *node, const struct qstr *nm)
1841{
1842 int err, len;
1843 const struct ubifs_dent_node *dent = node;
1844
1845 /*
1846 * We assume that in most of the cases there are no name collisions and
1847 * 'ubifs_tnc_lookup()' returns us the right direntry.
1848 */
1849 err = ubifs_tnc_lookup(c, key, node);
1850 if (err)
1851 return err;
1852
1853 len = le16_to_cpu(dent->nlen);
1854 if (nm->len == len && !memcmp(dent->name, nm->name, len))
1855 return 0;
1856
1857 /*
1858 * Unluckily, there are hash collisions and we have to iterate over
1859 * them look at each direntry with colliding name hash sequentially.
1860 */
1861 return do_lookup_nm(c, key, node, nm);
1862}
1863
1864/**
1865 * correct_parent_keys - correct parent znodes' keys.
1866 * @c: UBIFS file-system description object
1867 * @znode: znode to correct parent znodes for
1868 *
1869 * This is a helper function for 'tnc_insert()'. When the key of the leftmost
1870 * zbranch changes, keys of parent znodes have to be corrected. This helper
1871 * function is called in such situations and corrects the keys if needed.
1872 */
1873static void correct_parent_keys(const struct ubifs_info *c,
1874 struct ubifs_znode *znode)
1875{
1876 union ubifs_key *key, *key1;
1877
1878 ubifs_assert(znode->parent);
1879 ubifs_assert(znode->iip == 0);
1880
1881 key = &znode->zbranch[0].key;
1882 key1 = &znode->parent->zbranch[0].key;
1883
1884 while (keys_cmp(c, key, key1) < 0) {
1885 key_copy(c, key, key1);
1886 znode = znode->parent;
1887 znode->alt = 1;
1888 if (!znode->parent || znode->iip)
1889 break;
1890 key1 = &znode->parent->zbranch[0].key;
1891 }
1892}
1893
1894/**
1895 * insert_zbranch - insert a zbranch into a znode.
1896 * @znode: znode into which to insert
1897 * @zbr: zbranch to insert
1898 * @n: slot number to insert to
1899 *
1900 * This is a helper function for 'tnc_insert()'. UBIFS does not allow "gaps" in
1901 * znode's array of zbranches and keeps zbranches consolidated, so when a new
1902 * zbranch has to be inserted to the @znode->zbranches[]' array at the @n-th
1903 * slot, zbranches starting from @n have to be moved right.
1904 */
1905static void insert_zbranch(struct ubifs_znode *znode,
1906 const struct ubifs_zbranch *zbr, int n)
1907{
1908 int i;
1909
1910 ubifs_assert(ubifs_zn_dirty(znode));
1911
1912 if (znode->level) {
1913 for (i = znode->child_cnt; i > n; i--) {
1914 znode->zbranch[i] = znode->zbranch[i - 1];
1915 if (znode->zbranch[i].znode)
1916 znode->zbranch[i].znode->iip = i;
1917 }
1918 if (zbr->znode)
1919 zbr->znode->iip = n;
1920 } else
1921 for (i = znode->child_cnt; i > n; i--)
1922 znode->zbranch[i] = znode->zbranch[i - 1];
1923
1924 znode->zbranch[n] = *zbr;
1925 znode->child_cnt += 1;
1926
1927 /*
1928 * After inserting at slot zero, the lower bound of the key range of
1929 * this znode may have changed. If this znode is subsequently split
1930 * then the upper bound of the key range may change, and furthermore
1931 * it could change to be lower than the original lower bound. If that
1932 * happens, then it will no longer be possible to find this znode in the
1933 * TNC using the key from the index node on flash. That is bad because
1934 * if it is not found, we will assume it is obsolete and may overwrite
1935 * it. Then if there is an unclean unmount, we will start using the
1936 * old index which will be broken.
1937 *
1938 * So we first mark znodes that have insertions at slot zero, and then
1939 * if they are split we add their lnum/offs to the old_idx tree.
1940 */
1941 if (n == 0)
1942 znode->alt = 1;
1943}
1944
1945/**
1946 * tnc_insert - insert a node into TNC.
1947 * @c: UBIFS file-system description object
1948 * @znode: znode to insert into
1949 * @zbr: branch to insert
1950 * @n: slot number to insert new zbranch to
1951 *
1952 * This function inserts a new node described by @zbr into znode @znode. If
1953 * znode does not have a free slot for new zbranch, it is split. Parent znodes
1954 * are splat as well if needed. Returns zero in case of success or a negative
1955 * error code in case of failure.
1956 */
1957static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode,
1958 struct ubifs_zbranch *zbr, int n)
1959{
1960 struct ubifs_znode *zn, *zi, *zp;
1961 int i, keep, move, appending = 0;
Adrian Hunter2242c682008-09-05 11:56:05 +03001962 union ubifs_key *key = &zbr->key, *key1;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001963
1964 ubifs_assert(n >= 0 && n <= c->fanout);
1965
1966 /* Implement naive insert for now */
1967again:
1968 zp = znode->parent;
1969 if (znode->child_cnt < c->fanout) {
1970 ubifs_assert(n != c->fanout);
Artem Bityutskiy515315a2012-01-13 12:33:53 +02001971 dbg_tnck(key, "inserted at %d level %d, key ", n, znode->level);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001972
1973 insert_zbranch(znode, zbr, n);
1974
1975 /* Ensure parent's key is correct */
1976 if (n == 0 && zp && znode->iip == 0)
1977 correct_parent_keys(c, znode);
1978
1979 return 0;
1980 }
1981
1982 /*
1983 * Unfortunately, @znode does not have more empty slots and we have to
1984 * split it.
1985 */
Artem Bityutskiy515315a2012-01-13 12:33:53 +02001986 dbg_tnck(key, "splitting level %d, key ", znode->level);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001987
1988 if (znode->alt)
1989 /*
1990 * We can no longer be sure of finding this znode by key, so we
1991 * record it in the old_idx tree.
1992 */
1993 ins_clr_old_idx_znode(c, znode);
1994
1995 zn = kzalloc(c->max_znode_sz, GFP_NOFS);
1996 if (!zn)
1997 return -ENOMEM;
1998 zn->parent = zp;
1999 zn->level = znode->level;
2000
2001 /* Decide where to split */
Adrian Hunter2242c682008-09-05 11:56:05 +03002002 if (znode->level == 0 && key_type(c, key) == UBIFS_DATA_KEY) {
2003 /* Try not to split consecutive data keys */
2004 if (n == c->fanout) {
2005 key1 = &znode->zbranch[n - 1].key;
2006 if (key_inum(c, key1) == key_inum(c, key) &&
2007 key_type(c, key1) == UBIFS_DATA_KEY)
2008 appending = 1;
2009 } else
2010 goto check_split;
2011 } else if (appending && n != c->fanout) {
2012 /* Try not to split consecutive data keys */
2013 appending = 0;
2014check_split:
2015 if (n >= (c->fanout + 1) / 2) {
2016 key1 = &znode->zbranch[0].key;
2017 if (key_inum(c, key1) == key_inum(c, key) &&
2018 key_type(c, key1) == UBIFS_DATA_KEY) {
2019 key1 = &znode->zbranch[n].key;
2020 if (key_inum(c, key1) != key_inum(c, key) ||
2021 key_type(c, key1) != UBIFS_DATA_KEY) {
2022 keep = n;
2023 move = c->fanout - keep;
2024 zi = znode;
2025 goto do_split;
2026 }
2027 }
2028 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002029 }
2030
2031 if (appending) {
2032 keep = c->fanout;
2033 move = 0;
2034 } else {
2035 keep = (c->fanout + 1) / 2;
2036 move = c->fanout - keep;
2037 }
2038
2039 /*
2040 * Although we don't at present, we could look at the neighbors and see
2041 * if we can move some zbranches there.
2042 */
2043
2044 if (n < keep) {
2045 /* Insert into existing znode */
2046 zi = znode;
2047 move += 1;
2048 keep -= 1;
2049 } else {
2050 /* Insert into new znode */
2051 zi = zn;
2052 n -= keep;
2053 /* Re-parent */
2054 if (zn->level != 0)
2055 zbr->znode->parent = zn;
2056 }
2057
Adrian Hunter2242c682008-09-05 11:56:05 +03002058do_split:
2059
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002060 __set_bit(DIRTY_ZNODE, &zn->flags);
2061 atomic_long_inc(&c->dirty_zn_cnt);
2062
2063 zn->child_cnt = move;
2064 znode->child_cnt = keep;
2065
2066 dbg_tnc("moving %d, keeping %d", move, keep);
2067
2068 /* Move zbranch */
2069 for (i = 0; i < move; i++) {
2070 zn->zbranch[i] = znode->zbranch[keep + i];
2071 /* Re-parent */
2072 if (zn->level != 0)
2073 if (zn->zbranch[i].znode) {
2074 zn->zbranch[i].znode->parent = zn;
2075 zn->zbranch[i].znode->iip = i;
2076 }
2077 }
2078
2079 /* Insert new key and branch */
Artem Bityutskiy515315a2012-01-13 12:33:53 +02002080 dbg_tnck(key, "inserting at %d level %d, key ", n, zn->level);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002081
2082 insert_zbranch(zi, zbr, n);
2083
2084 /* Insert new znode (produced by spitting) into the parent */
2085 if (zp) {
Adrian Hunter2242c682008-09-05 11:56:05 +03002086 if (n == 0 && zi == znode && znode->iip == 0)
2087 correct_parent_keys(c, znode);
2088
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002089 /* Locate insertion point */
2090 n = znode->iip + 1;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002091
2092 /* Tail recursion */
2093 zbr->key = zn->zbranch[0].key;
2094 zbr->znode = zn;
2095 zbr->lnum = 0;
2096 zbr->offs = 0;
2097 zbr->len = 0;
2098 znode = zp;
2099
2100 goto again;
2101 }
2102
2103 /* We have to split root znode */
2104 dbg_tnc("creating new zroot at level %d", znode->level + 1);
2105
2106 zi = kzalloc(c->max_znode_sz, GFP_NOFS);
2107 if (!zi)
2108 return -ENOMEM;
2109
2110 zi->child_cnt = 2;
2111 zi->level = znode->level + 1;
2112
2113 __set_bit(DIRTY_ZNODE, &zi->flags);
2114 atomic_long_inc(&c->dirty_zn_cnt);
2115
2116 zi->zbranch[0].key = znode->zbranch[0].key;
2117 zi->zbranch[0].znode = znode;
2118 zi->zbranch[0].lnum = c->zroot.lnum;
2119 zi->zbranch[0].offs = c->zroot.offs;
2120 zi->zbranch[0].len = c->zroot.len;
2121 zi->zbranch[1].key = zn->zbranch[0].key;
2122 zi->zbranch[1].znode = zn;
2123
2124 c->zroot.lnum = 0;
2125 c->zroot.offs = 0;
2126 c->zroot.len = 0;
2127 c->zroot.znode = zi;
2128
2129 zn->parent = zi;
2130 zn->iip = 1;
2131 znode->parent = zi;
2132 znode->iip = 0;
2133
2134 return 0;
2135}
2136
2137/**
2138 * ubifs_tnc_add - add a node to TNC.
2139 * @c: UBIFS file-system description object
2140 * @key: key to add
2141 * @lnum: LEB number of node
2142 * @offs: node offset
2143 * @len: node length
2144 *
2145 * This function adds a node with key @key to TNC. The node may be new or it may
2146 * obsolete some existing one. Returns %0 on success or negative error code on
2147 * failure.
2148 */
2149int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum,
2150 int offs, int len)
2151{
2152 int found, n, err = 0;
2153 struct ubifs_znode *znode;
2154
2155 mutex_lock(&c->tnc_mutex);
Artem Bityutskiy515315a2012-01-13 12:33:53 +02002156 dbg_tnck(key, "%d:%d, len %d, key ", lnum, offs, len);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002157 found = lookup_level0_dirty(c, key, &znode, &n);
2158 if (!found) {
2159 struct ubifs_zbranch zbr;
2160
2161 zbr.znode = NULL;
2162 zbr.lnum = lnum;
2163 zbr.offs = offs;
2164 zbr.len = len;
2165 key_copy(c, key, &zbr.key);
2166 err = tnc_insert(c, znode, &zbr, n + 1);
2167 } else if (found == 1) {
2168 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2169
2170 lnc_free(zbr);
2171 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2172 zbr->lnum = lnum;
2173 zbr->offs = offs;
2174 zbr->len = len;
2175 } else
2176 err = found;
2177 if (!err)
2178 err = dbg_check_tnc(c, 0);
2179 mutex_unlock(&c->tnc_mutex);
2180
2181 return err;
2182}
2183
2184/**
2185 * ubifs_tnc_replace - replace a node in the TNC only if the old node is found.
2186 * @c: UBIFS file-system description object
2187 * @key: key to add
2188 * @old_lnum: LEB number of old node
2189 * @old_offs: old node offset
2190 * @lnum: LEB number of node
2191 * @offs: node offset
2192 * @len: node length
2193 *
2194 * This function replaces a node with key @key in the TNC only if the old node
2195 * is found. This function is called by garbage collection when node are moved.
2196 * Returns %0 on success or negative error code on failure.
2197 */
2198int ubifs_tnc_replace(struct ubifs_info *c, const union ubifs_key *key,
2199 int old_lnum, int old_offs, int lnum, int offs, int len)
2200{
2201 int found, n, err = 0;
2202 struct ubifs_znode *znode;
2203
2204 mutex_lock(&c->tnc_mutex);
Artem Bityutskiy515315a2012-01-13 12:33:53 +02002205 dbg_tnck(key, "old LEB %d:%d, new LEB %d:%d, len %d, key ", old_lnum,
2206 old_offs, lnum, offs, len);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002207 found = lookup_level0_dirty(c, key, &znode, &n);
2208 if (found < 0) {
2209 err = found;
2210 goto out_unlock;
2211 }
2212
2213 if (found == 1) {
2214 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2215
2216 found = 0;
2217 if (zbr->lnum == old_lnum && zbr->offs == old_offs) {
2218 lnc_free(zbr);
2219 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2220 if (err)
2221 goto out_unlock;
2222 zbr->lnum = lnum;
2223 zbr->offs = offs;
2224 zbr->len = len;
2225 found = 1;
2226 } else if (is_hash_key(c, key)) {
2227 found = resolve_collision_directly(c, key, &znode, &n,
2228 old_lnum, old_offs);
2229 dbg_tnc("rc returned %d, znode %p, n %d, LEB %d:%d",
2230 found, znode, n, old_lnum, old_offs);
2231 if (found < 0) {
2232 err = found;
2233 goto out_unlock;
2234 }
2235
2236 if (found) {
2237 /* Ensure the znode is dirtied */
2238 if (znode->cnext || !ubifs_zn_dirty(znode)) {
Artem Bityutskiyf92b9822008-12-28 11:34:26 +02002239 znode = dirty_cow_bottom_up(c, znode);
2240 if (IS_ERR(znode)) {
2241 err = PTR_ERR(znode);
2242 goto out_unlock;
2243 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002244 }
2245 zbr = &znode->zbranch[n];
2246 lnc_free(zbr);
2247 err = ubifs_add_dirt(c, zbr->lnum,
2248 zbr->len);
2249 if (err)
2250 goto out_unlock;
2251 zbr->lnum = lnum;
2252 zbr->offs = offs;
2253 zbr->len = len;
2254 }
2255 }
2256 }
2257
2258 if (!found)
2259 err = ubifs_add_dirt(c, lnum, len);
2260
2261 if (!err)
2262 err = dbg_check_tnc(c, 0);
2263
2264out_unlock:
2265 mutex_unlock(&c->tnc_mutex);
2266 return err;
2267}
2268
2269/**
2270 * ubifs_tnc_add_nm - add a "hashed" node to TNC.
2271 * @c: UBIFS file-system description object
2272 * @key: key to add
2273 * @lnum: LEB number of node
2274 * @offs: node offset
2275 * @len: node length
2276 * @nm: node name
2277 *
2278 * This is the same as 'ubifs_tnc_add()' but it should be used with keys which
2279 * may have collisions, like directory entry keys.
2280 */
2281int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
2282 int lnum, int offs, int len, const struct qstr *nm)
2283{
2284 int found, n, err = 0;
2285 struct ubifs_znode *znode;
2286
2287 mutex_lock(&c->tnc_mutex);
Artem Bityutskiy515315a2012-01-13 12:33:53 +02002288 dbg_tnck(key, "LEB %d:%d, name '%.*s', key ",
2289 lnum, offs, nm->len, nm->name);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002290 found = lookup_level0_dirty(c, key, &znode, &n);
2291 if (found < 0) {
2292 err = found;
2293 goto out_unlock;
2294 }
2295
2296 if (found == 1) {
2297 if (c->replaying)
2298 found = fallible_resolve_collision(c, key, &znode, &n,
2299 nm, 1);
2300 else
2301 found = resolve_collision(c, key, &znode, &n, nm);
2302 dbg_tnc("rc returned %d, znode %p, n %d", found, znode, n);
2303 if (found < 0) {
2304 err = found;
2305 goto out_unlock;
2306 }
2307
2308 /* Ensure the znode is dirtied */
2309 if (znode->cnext || !ubifs_zn_dirty(znode)) {
Artem Bityutskiyf92b9822008-12-28 11:34:26 +02002310 znode = dirty_cow_bottom_up(c, znode);
2311 if (IS_ERR(znode)) {
2312 err = PTR_ERR(znode);
2313 goto out_unlock;
2314 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002315 }
2316
2317 if (found == 1) {
2318 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2319
2320 lnc_free(zbr);
2321 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2322 zbr->lnum = lnum;
2323 zbr->offs = offs;
2324 zbr->len = len;
2325 goto out_unlock;
2326 }
2327 }
2328
2329 if (!found) {
2330 struct ubifs_zbranch zbr;
2331
2332 zbr.znode = NULL;
2333 zbr.lnum = lnum;
2334 zbr.offs = offs;
2335 zbr.len = len;
2336 key_copy(c, key, &zbr.key);
2337 err = tnc_insert(c, znode, &zbr, n + 1);
2338 if (err)
2339 goto out_unlock;
2340 if (c->replaying) {
2341 /*
2342 * We did not find it in the index so there may be a
2343 * dangling branch still in the index. So we remove it
2344 * by passing 'ubifs_tnc_remove_nm()' the same key but
2345 * an unmatchable name.
2346 */
Linus Torvalds26fe5752012-05-10 13:14:12 -07002347 struct qstr noname = { .name = "" };
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002348
2349 err = dbg_check_tnc(c, 0);
2350 mutex_unlock(&c->tnc_mutex);
2351 if (err)
2352 return err;
2353 return ubifs_tnc_remove_nm(c, key, &noname);
2354 }
2355 }
2356
2357out_unlock:
2358 if (!err)
2359 err = dbg_check_tnc(c, 0);
2360 mutex_unlock(&c->tnc_mutex);
2361 return err;
2362}
2363
2364/**
2365 * tnc_delete - delete a znode form TNC.
2366 * @c: UBIFS file-system description object
2367 * @znode: znode to delete from
2368 * @n: zbranch slot number to delete
2369 *
2370 * This function deletes a leaf node from @n-th slot of @znode. Returns zero in
2371 * case of success and a negative error code in case of failure.
2372 */
2373static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n)
2374{
2375 struct ubifs_zbranch *zbr;
2376 struct ubifs_znode *zp;
2377 int i, err;
2378
2379 /* Delete without merge for now */
2380 ubifs_assert(znode->level == 0);
2381 ubifs_assert(n >= 0 && n < c->fanout);
Artem Bityutskiy515315a2012-01-13 12:33:53 +02002382 dbg_tnck(&znode->zbranch[n].key, "deleting key ");
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002383
2384 zbr = &znode->zbranch[n];
2385 lnc_free(zbr);
2386
2387 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2388 if (err) {
Artem Bityutskiyedf6be22012-05-16 19:15:56 +03002389 ubifs_dump_znode(c, znode);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002390 return err;
2391 }
2392
2393 /* We do not "gap" zbranch slots */
2394 for (i = n; i < znode->child_cnt - 1; i++)
2395 znode->zbranch[i] = znode->zbranch[i + 1];
2396 znode->child_cnt -= 1;
2397
2398 if (znode->child_cnt > 0)
2399 return 0;
2400
2401 /*
2402 * This was the last zbranch, we have to delete this znode from the
2403 * parent.
2404 */
2405
2406 do {
Artem Bityutskiyf42eed72011-05-30 14:45:30 +03002407 ubifs_assert(!ubifs_zn_obsolete(znode));
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002408 ubifs_assert(ubifs_zn_dirty(znode));
2409
2410 zp = znode->parent;
2411 n = znode->iip;
2412
2413 atomic_long_dec(&c->dirty_zn_cnt);
2414
2415 err = insert_old_idx_znode(c, znode);
2416 if (err)
2417 return err;
2418
2419 if (znode->cnext) {
2420 __set_bit(OBSOLETE_ZNODE, &znode->flags);
2421 atomic_long_inc(&c->clean_zn_cnt);
2422 atomic_long_inc(&ubifs_clean_zn_cnt);
2423 } else
2424 kfree(znode);
2425 znode = zp;
2426 } while (znode->child_cnt == 1); /* while removing last child */
2427
2428 /* Remove from znode, entry n - 1 */
2429 znode->child_cnt -= 1;
2430 ubifs_assert(znode->level != 0);
2431 for (i = n; i < znode->child_cnt; i++) {
2432 znode->zbranch[i] = znode->zbranch[i + 1];
2433 if (znode->zbranch[i].znode)
2434 znode->zbranch[i].znode->iip = i;
2435 }
2436
2437 /*
2438 * If this is the root and it has only 1 child then
2439 * collapse the tree.
2440 */
2441 if (!znode->parent) {
2442 while (znode->child_cnt == 1 && znode->level != 0) {
2443 zp = znode;
2444 zbr = &znode->zbranch[0];
2445 znode = get_znode(c, znode, 0);
2446 if (IS_ERR(znode))
2447 return PTR_ERR(znode);
2448 znode = dirty_cow_znode(c, zbr);
2449 if (IS_ERR(znode))
2450 return PTR_ERR(znode);
2451 znode->parent = NULL;
2452 znode->iip = 0;
2453 if (c->zroot.len) {
2454 err = insert_old_idx(c, c->zroot.lnum,
2455 c->zroot.offs);
2456 if (err)
2457 return err;
2458 }
2459 c->zroot.lnum = zbr->lnum;
2460 c->zroot.offs = zbr->offs;
2461 c->zroot.len = zbr->len;
2462 c->zroot.znode = znode;
Artem Bityutskiyf42eed72011-05-30 14:45:30 +03002463 ubifs_assert(!ubifs_zn_obsolete(zp));
2464 ubifs_assert(ubifs_zn_dirty(zp));
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002465 atomic_long_dec(&c->dirty_zn_cnt);
2466
2467 if (zp->cnext) {
2468 __set_bit(OBSOLETE_ZNODE, &zp->flags);
2469 atomic_long_inc(&c->clean_zn_cnt);
2470 atomic_long_inc(&ubifs_clean_zn_cnt);
2471 } else
2472 kfree(zp);
2473 }
2474 }
2475
2476 return 0;
2477}
2478
2479/**
2480 * ubifs_tnc_remove - remove an index entry of a node.
2481 * @c: UBIFS file-system description object
2482 * @key: key of node
2483 *
2484 * Returns %0 on success or negative error code on failure.
2485 */
2486int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key)
2487{
2488 int found, n, err = 0;
2489 struct ubifs_znode *znode;
2490
2491 mutex_lock(&c->tnc_mutex);
Artem Bityutskiy515315a2012-01-13 12:33:53 +02002492 dbg_tnck(key, "key ");
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002493 found = lookup_level0_dirty(c, key, &znode, &n);
2494 if (found < 0) {
2495 err = found;
2496 goto out_unlock;
2497 }
2498 if (found == 1)
2499 err = tnc_delete(c, znode, n);
2500 if (!err)
2501 err = dbg_check_tnc(c, 0);
2502
2503out_unlock:
2504 mutex_unlock(&c->tnc_mutex);
2505 return err;
2506}
2507
2508/**
2509 * ubifs_tnc_remove_nm - remove an index entry for a "hashed" node.
2510 * @c: UBIFS file-system description object
2511 * @key: key of node
2512 * @nm: directory entry name
2513 *
2514 * Returns %0 on success or negative error code on failure.
2515 */
2516int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
2517 const struct qstr *nm)
2518{
2519 int n, err;
2520 struct ubifs_znode *znode;
2521
2522 mutex_lock(&c->tnc_mutex);
Artem Bityutskiy515315a2012-01-13 12:33:53 +02002523 dbg_tnck(key, "%.*s, key ", nm->len, nm->name);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002524 err = lookup_level0_dirty(c, key, &znode, &n);
2525 if (err < 0)
2526 goto out_unlock;
2527
2528 if (err) {
2529 if (c->replaying)
2530 err = fallible_resolve_collision(c, key, &znode, &n,
2531 nm, 0);
2532 else
2533 err = resolve_collision(c, key, &znode, &n, nm);
2534 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
2535 if (err < 0)
2536 goto out_unlock;
2537 if (err) {
2538 /* Ensure the znode is dirtied */
2539 if (znode->cnext || !ubifs_zn_dirty(znode)) {
Artem Bityutskiyc4361572011-03-25 15:27:40 +02002540 znode = dirty_cow_bottom_up(c, znode);
2541 if (IS_ERR(znode)) {
2542 err = PTR_ERR(znode);
2543 goto out_unlock;
2544 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002545 }
2546 err = tnc_delete(c, znode, n);
2547 }
2548 }
2549
2550out_unlock:
2551 if (!err)
2552 err = dbg_check_tnc(c, 0);
2553 mutex_unlock(&c->tnc_mutex);
2554 return err;
2555}
2556
2557/**
2558 * key_in_range - determine if a key falls within a range of keys.
2559 * @c: UBIFS file-system description object
2560 * @key: key to check
2561 * @from_key: lowest key in range
2562 * @to_key: highest key in range
2563 *
2564 * This function returns %1 if the key is in range and %0 otherwise.
2565 */
2566static int key_in_range(struct ubifs_info *c, union ubifs_key *key,
2567 union ubifs_key *from_key, union ubifs_key *to_key)
2568{
2569 if (keys_cmp(c, key, from_key) < 0)
2570 return 0;
2571 if (keys_cmp(c, key, to_key) > 0)
2572 return 0;
2573 return 1;
2574}
2575
2576/**
2577 * ubifs_tnc_remove_range - remove index entries in range.
2578 * @c: UBIFS file-system description object
2579 * @from_key: lowest key to remove
2580 * @to_key: highest key to remove
2581 *
2582 * This function removes index entries starting at @from_key and ending at
2583 * @to_key. This function returns zero in case of success and a negative error
2584 * code in case of failure.
2585 */
2586int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key,
2587 union ubifs_key *to_key)
2588{
2589 int i, n, k, err = 0;
2590 struct ubifs_znode *znode;
2591 union ubifs_key *key;
2592
2593 mutex_lock(&c->tnc_mutex);
2594 while (1) {
2595 /* Find first level 0 znode that contains keys to remove */
2596 err = ubifs_lookup_level0(c, from_key, &znode, &n);
2597 if (err < 0)
2598 goto out_unlock;
2599
2600 if (err)
2601 key = from_key;
2602 else {
2603 err = tnc_next(c, &znode, &n);
2604 if (err == -ENOENT) {
2605 err = 0;
2606 goto out_unlock;
2607 }
2608 if (err < 0)
2609 goto out_unlock;
2610 key = &znode->zbranch[n].key;
2611 if (!key_in_range(c, key, from_key, to_key)) {
2612 err = 0;
2613 goto out_unlock;
2614 }
2615 }
2616
2617 /* Ensure the znode is dirtied */
2618 if (znode->cnext || !ubifs_zn_dirty(znode)) {
Artem Bityutskiyf92b9822008-12-28 11:34:26 +02002619 znode = dirty_cow_bottom_up(c, znode);
2620 if (IS_ERR(znode)) {
2621 err = PTR_ERR(znode);
2622 goto out_unlock;
2623 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002624 }
2625
2626 /* Remove all keys in range except the first */
2627 for (i = n + 1, k = 0; i < znode->child_cnt; i++, k++) {
2628 key = &znode->zbranch[i].key;
2629 if (!key_in_range(c, key, from_key, to_key))
2630 break;
2631 lnc_free(&znode->zbranch[i]);
2632 err = ubifs_add_dirt(c, znode->zbranch[i].lnum,
2633 znode->zbranch[i].len);
2634 if (err) {
Artem Bityutskiyedf6be22012-05-16 19:15:56 +03002635 ubifs_dump_znode(c, znode);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002636 goto out_unlock;
2637 }
Artem Bityutskiy515315a2012-01-13 12:33:53 +02002638 dbg_tnck(key, "removing key ");
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002639 }
2640 if (k) {
2641 for (i = n + 1 + k; i < znode->child_cnt; i++)
2642 znode->zbranch[i - k] = znode->zbranch[i];
2643 znode->child_cnt -= k;
2644 }
2645
2646 /* Now delete the first */
2647 err = tnc_delete(c, znode, n);
2648 if (err)
2649 goto out_unlock;
2650 }
2651
2652out_unlock:
2653 if (!err)
2654 err = dbg_check_tnc(c, 0);
2655 mutex_unlock(&c->tnc_mutex);
2656 return err;
2657}
2658
2659/**
2660 * ubifs_tnc_remove_ino - remove an inode from TNC.
2661 * @c: UBIFS file-system description object
2662 * @inum: inode number to remove
2663 *
2664 * This function remove inode @inum and all the extended attributes associated
2665 * with the anode from TNC and returns zero in case of success or a negative
2666 * error code in case of failure.
2667 */
2668int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum)
2669{
2670 union ubifs_key key1, key2;
2671 struct ubifs_dent_node *xent, *pxent = NULL;
2672 struct qstr nm = { .name = NULL };
2673
Artem Bityutskiye84461a2008-10-29 12:08:43 +02002674 dbg_tnc("ino %lu", (unsigned long)inum);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002675
2676 /*
2677 * Walk all extended attribute entries and remove them together with
2678 * corresponding extended attribute inodes.
2679 */
2680 lowest_xent_key(c, &key1, inum);
2681 while (1) {
2682 ino_t xattr_inum;
2683 int err;
2684
2685 xent = ubifs_tnc_next_ent(c, &key1, &nm);
2686 if (IS_ERR(xent)) {
2687 err = PTR_ERR(xent);
2688 if (err == -ENOENT)
2689 break;
2690 return err;
2691 }
2692
2693 xattr_inum = le64_to_cpu(xent->inum);
Artem Bityutskiye84461a2008-10-29 12:08:43 +02002694 dbg_tnc("xent '%s', ino %lu", xent->name,
2695 (unsigned long)xattr_inum);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002696
2697 nm.name = xent->name;
2698 nm.len = le16_to_cpu(xent->nlen);
2699 err = ubifs_tnc_remove_nm(c, &key1, &nm);
2700 if (err) {
2701 kfree(xent);
2702 return err;
2703 }
2704
2705 lowest_ino_key(c, &key1, xattr_inum);
2706 highest_ino_key(c, &key2, xattr_inum);
2707 err = ubifs_tnc_remove_range(c, &key1, &key2);
2708 if (err) {
2709 kfree(xent);
2710 return err;
2711 }
2712
2713 kfree(pxent);
2714 pxent = xent;
2715 key_read(c, &xent->key, &key1);
2716 }
2717
2718 kfree(pxent);
2719 lowest_ino_key(c, &key1, inum);
2720 highest_ino_key(c, &key2, inum);
2721
2722 return ubifs_tnc_remove_range(c, &key1, &key2);
2723}
2724
2725/**
2726 * ubifs_tnc_next_ent - walk directory or extended attribute entries.
2727 * @c: UBIFS file-system description object
2728 * @key: key of last entry
2729 * @nm: name of last entry found or %NULL
2730 *
2731 * This function finds and reads the next directory or extended attribute entry
2732 * after the given key (@key) if there is one. @nm is used to resolve
2733 * collisions.
2734 *
2735 * If the name of the current entry is not known and only the key is known,
2736 * @nm->name has to be %NULL. In this case the semantics of this function is a
2737 * little bit different and it returns the entry corresponding to this key, not
2738 * the next one. If the key was not found, the closest "right" entry is
2739 * returned.
2740 *
2741 * If the fist entry has to be found, @key has to contain the lowest possible
2742 * key value for this inode and @name has to be %NULL.
2743 *
2744 * This function returns the found directory or extended attribute entry node
2745 * in case of success, %-ENOENT is returned if no entry was found, and a
2746 * negative error code is returned in case of failure.
2747 */
2748struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c,
2749 union ubifs_key *key,
2750 const struct qstr *nm)
2751{
2752 int n, err, type = key_type(c, key);
2753 struct ubifs_znode *znode;
2754 struct ubifs_dent_node *dent;
2755 struct ubifs_zbranch *zbr;
2756 union ubifs_key *dkey;
2757
Artem Bityutskiy515315a2012-01-13 12:33:53 +02002758 dbg_tnck(key, "%s ", nm->name ? (char *)nm->name : "(lowest)");
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002759 ubifs_assert(is_hash_key(c, key));
2760
2761 mutex_lock(&c->tnc_mutex);
2762 err = ubifs_lookup_level0(c, key, &znode, &n);
2763 if (unlikely(err < 0))
2764 goto out_unlock;
2765
2766 if (nm->name) {
2767 if (err) {
2768 /* Handle collisions */
2769 err = resolve_collision(c, key, &znode, &n, nm);
2770 dbg_tnc("rc returned %d, znode %p, n %d",
2771 err, znode, n);
2772 if (unlikely(err < 0))
2773 goto out_unlock;
2774 }
2775
2776 /* Now find next entry */
2777 err = tnc_next(c, &znode, &n);
2778 if (unlikely(err))
2779 goto out_unlock;
2780 } else {
2781 /*
2782 * The full name of the entry was not given, in which case the
2783 * behavior of this function is a little different and it
2784 * returns current entry, not the next one.
2785 */
2786 if (!err) {
2787 /*
2788 * However, the given key does not exist in the TNC
2789 * tree and @znode/@n variables contain the closest
2790 * "preceding" element. Switch to the next one.
2791 */
2792 err = tnc_next(c, &znode, &n);
2793 if (err)
2794 goto out_unlock;
2795 }
2796 }
2797
2798 zbr = &znode->zbranch[n];
2799 dent = kmalloc(zbr->len, GFP_NOFS);
2800 if (unlikely(!dent)) {
2801 err = -ENOMEM;
2802 goto out_unlock;
2803 }
2804
2805 /*
2806 * The above 'tnc_next()' call could lead us to the next inode, check
2807 * this.
2808 */
2809 dkey = &zbr->key;
2810 if (key_inum(c, dkey) != key_inum(c, key) ||
2811 key_type(c, dkey) != type) {
2812 err = -ENOENT;
2813 goto out_free;
2814 }
2815
2816 err = tnc_read_node_nm(c, zbr, dent);
2817 if (unlikely(err))
2818 goto out_free;
2819
2820 mutex_unlock(&c->tnc_mutex);
2821 return dent;
2822
2823out_free:
2824 kfree(dent);
2825out_unlock:
2826 mutex_unlock(&c->tnc_mutex);
2827 return ERR_PTR(err);
2828}
2829
2830/**
2831 * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit.
2832 * @c: UBIFS file-system description object
2833 *
2834 * Destroy left-over obsolete znodes from a failed commit.
2835 */
2836static void tnc_destroy_cnext(struct ubifs_info *c)
2837{
2838 struct ubifs_znode *cnext;
2839
2840 if (!c->cnext)
2841 return;
2842 ubifs_assert(c->cmt_state == COMMIT_BROKEN);
2843 cnext = c->cnext;
2844 do {
2845 struct ubifs_znode *znode = cnext;
2846
2847 cnext = cnext->cnext;
Artem Bityutskiyf42eed72011-05-30 14:45:30 +03002848 if (ubifs_zn_obsolete(znode))
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002849 kfree(znode);
2850 } while (cnext && cnext != c->cnext);
2851}
2852
2853/**
2854 * ubifs_tnc_close - close TNC subsystem and free all related resources.
2855 * @c: UBIFS file-system description object
2856 */
2857void ubifs_tnc_close(struct ubifs_info *c)
2858{
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002859 tnc_destroy_cnext(c);
2860 if (c->zroot.znode) {
hujianyang380347e2014-06-03 14:49:11 +08002861 long n, freed;
Artem Bityutskiy83707232011-05-31 14:26:07 +03002862
Artem Bityutskiy83707232011-05-31 14:26:07 +03002863 n = atomic_long_read(&c->clean_zn_cnt);
hujianyang380347e2014-06-03 14:49:11 +08002864 freed = ubifs_destroy_tnc_subtree(c->zroot.znode);
2865 ubifs_assert(freed == n);
Artem Bityutskiy83707232011-05-31 14:26:07 +03002866 atomic_long_sub(n, &ubifs_clean_zn_cnt);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002867 }
2868 kfree(c->gap_lebs);
2869 kfree(c->ilebs);
2870 destroy_old_idx(c);
2871}
2872
2873/**
2874 * left_znode - get the znode to the left.
2875 * @c: UBIFS file-system description object
2876 * @znode: znode
2877 *
2878 * This function returns a pointer to the znode to the left of @znode or NULL if
2879 * there is not one. A negative error code is returned on failure.
2880 */
2881static struct ubifs_znode *left_znode(struct ubifs_info *c,
2882 struct ubifs_znode *znode)
2883{
2884 int level = znode->level;
2885
2886 while (1) {
2887 int n = znode->iip - 1;
2888
2889 /* Go up until we can go left */
2890 znode = znode->parent;
2891 if (!znode)
2892 return NULL;
2893 if (n >= 0) {
2894 /* Now go down the rightmost branch to 'level' */
2895 znode = get_znode(c, znode, n);
2896 if (IS_ERR(znode))
2897 return znode;
2898 while (znode->level != level) {
2899 n = znode->child_cnt - 1;
2900 znode = get_znode(c, znode, n);
2901 if (IS_ERR(znode))
2902 return znode;
2903 }
2904 break;
2905 }
2906 }
2907 return znode;
2908}
2909
2910/**
2911 * right_znode - get the znode to the right.
2912 * @c: UBIFS file-system description object
2913 * @znode: znode
2914 *
2915 * This function returns a pointer to the znode to the right of @znode or NULL
2916 * if there is not one. A negative error code is returned on failure.
2917 */
2918static struct ubifs_znode *right_znode(struct ubifs_info *c,
2919 struct ubifs_znode *znode)
2920{
2921 int level = znode->level;
2922
2923 while (1) {
2924 int n = znode->iip + 1;
2925
2926 /* Go up until we can go right */
2927 znode = znode->parent;
2928 if (!znode)
2929 return NULL;
2930 if (n < znode->child_cnt) {
2931 /* Now go down the leftmost branch to 'level' */
2932 znode = get_znode(c, znode, n);
2933 if (IS_ERR(znode))
2934 return znode;
2935 while (znode->level != level) {
2936 znode = get_znode(c, znode, 0);
2937 if (IS_ERR(znode))
2938 return znode;
2939 }
2940 break;
2941 }
2942 }
2943 return znode;
2944}
2945
2946/**
2947 * lookup_znode - find a particular indexing node from TNC.
2948 * @c: UBIFS file-system description object
2949 * @key: index node key to lookup
2950 * @level: index node level
2951 * @lnum: index node LEB number
2952 * @offs: index node offset
2953 *
2954 * This function searches an indexing node by its first key @key and its
2955 * address @lnum:@offs. It looks up the indexing tree by pulling all indexing
Artem Bityutskiyba2f48f2010-08-22 07:10:12 +03002956 * nodes it traverses to TNC. This function is called for indexing nodes which
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002957 * were found on the media by scanning, for example when garbage-collecting or
2958 * when doing in-the-gaps commit. This means that the indexing node which is
2959 * looked for does not have to have exactly the same leftmost key @key, because
2960 * the leftmost key may have been changed, in which case TNC will contain a
2961 * dirty znode which still refers the same @lnum:@offs. This function is clever
2962 * enough to recognize such indexing nodes.
2963 *
2964 * Note, if a znode was deleted or changed too much, then this function will
2965 * not find it. For situations like this UBIFS has the old index RB-tree
2966 * (indexed by @lnum:@offs).
2967 *
2968 * This function returns a pointer to the znode found or %NULL if it is not
2969 * found. A negative error code is returned on failure.
2970 */
2971static struct ubifs_znode *lookup_znode(struct ubifs_info *c,
2972 union ubifs_key *key, int level,
2973 int lnum, int offs)
2974{
2975 struct ubifs_znode *znode, *zn;
2976 int n, nn;
2977
Artem Bityutskiyba2f48f2010-08-22 07:10:12 +03002978 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
2979
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002980 /*
2981 * The arguments have probably been read off flash, so don't assume
2982 * they are valid.
2983 */
2984 if (level < 0)
2985 return ERR_PTR(-EINVAL);
2986
2987 /* Get the root znode */
2988 znode = c->zroot.znode;
2989 if (!znode) {
2990 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
2991 if (IS_ERR(znode))
2992 return znode;
2993 }
2994 /* Check if it is the one we are looking for */
2995 if (c->zroot.lnum == lnum && c->zroot.offs == offs)
2996 return znode;
2997 /* Descend to the parent level i.e. (level + 1) */
2998 if (level >= znode->level)
2999 return NULL;
3000 while (1) {
3001 ubifs_search_zbranch(c, znode, key, &n);
3002 if (n < 0) {
3003 /*
3004 * We reached a znode where the leftmost key is greater
3005 * than the key we are searching for. This is the same
3006 * situation as the one described in a huge comment at
3007 * the end of the 'ubifs_lookup_level0()' function. And
3008 * for exactly the same reasons we have to try to look
3009 * left before giving up.
3010 */
3011 znode = left_znode(c, znode);
3012 if (!znode)
3013 return NULL;
3014 if (IS_ERR(znode))
3015 return znode;
3016 ubifs_search_zbranch(c, znode, key, &n);
3017 ubifs_assert(n >= 0);
3018 }
3019 if (znode->level == level + 1)
3020 break;
3021 znode = get_znode(c, znode, n);
3022 if (IS_ERR(znode))
3023 return znode;
3024 }
3025 /* Check if the child is the one we are looking for */
3026 if (znode->zbranch[n].lnum == lnum && znode->zbranch[n].offs == offs)
3027 return get_znode(c, znode, n);
3028 /* If the key is unique, there is nowhere else to look */
3029 if (!is_hash_key(c, key))
3030 return NULL;
3031 /*
3032 * The key is not unique and so may be also in the znodes to either
3033 * side.
3034 */
3035 zn = znode;
3036 nn = n;
3037 /* Look left */
3038 while (1) {
3039 /* Move one branch to the left */
3040 if (n)
3041 n -= 1;
3042 else {
3043 znode = left_znode(c, znode);
3044 if (!znode)
3045 break;
3046 if (IS_ERR(znode))
3047 return znode;
3048 n = znode->child_cnt - 1;
3049 }
3050 /* Check it */
3051 if (znode->zbranch[n].lnum == lnum &&
3052 znode->zbranch[n].offs == offs)
3053 return get_znode(c, znode, n);
3054 /* Stop if the key is less than the one we are looking for */
3055 if (keys_cmp(c, &znode->zbranch[n].key, key) < 0)
3056 break;
3057 }
3058 /* Back to the middle */
3059 znode = zn;
3060 n = nn;
3061 /* Look right */
3062 while (1) {
3063 /* Move one branch to the right */
3064 if (++n >= znode->child_cnt) {
3065 znode = right_znode(c, znode);
3066 if (!znode)
3067 break;
3068 if (IS_ERR(znode))
3069 return znode;
3070 n = 0;
3071 }
3072 /* Check it */
3073 if (znode->zbranch[n].lnum == lnum &&
3074 znode->zbranch[n].offs == offs)
3075 return get_znode(c, znode, n);
3076 /* Stop if the key is greater than the one we are looking for */
3077 if (keys_cmp(c, &znode->zbranch[n].key, key) > 0)
3078 break;
3079 }
3080 return NULL;
3081}
3082
3083/**
3084 * is_idx_node_in_tnc - determine if an index node is in the TNC.
3085 * @c: UBIFS file-system description object
3086 * @key: key of index node
3087 * @level: index node level
3088 * @lnum: LEB number of index node
3089 * @offs: offset of index node
3090 *
3091 * This function returns %0 if the index node is not referred to in the TNC, %1
3092 * if the index node is referred to in the TNC and the corresponding znode is
3093 * dirty, %2 if an index node is referred to in the TNC and the corresponding
3094 * znode is clean, and a negative error code in case of failure.
3095 *
3096 * Note, the @key argument has to be the key of the first child. Also note,
3097 * this function relies on the fact that 0:0 is never a valid LEB number and
3098 * offset for a main-area node.
3099 */
3100int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level,
3101 int lnum, int offs)
3102{
3103 struct ubifs_znode *znode;
3104
3105 znode = lookup_znode(c, key, level, lnum, offs);
3106 if (!znode)
3107 return 0;
3108 if (IS_ERR(znode))
3109 return PTR_ERR(znode);
3110
3111 return ubifs_zn_dirty(znode) ? 1 : 2;
3112}
3113
3114/**
3115 * is_leaf_node_in_tnc - determine if a non-indexing not is in the TNC.
3116 * @c: UBIFS file-system description object
3117 * @key: node key
3118 * @lnum: node LEB number
3119 * @offs: node offset
3120 *
3121 * This function returns %1 if the node is referred to in the TNC, %0 if it is
3122 * not, and a negative error code in case of failure.
3123 *
3124 * Note, this function relies on the fact that 0:0 is never a valid LEB number
3125 * and offset for a main-area node.
3126 */
3127static int is_leaf_node_in_tnc(struct ubifs_info *c, union ubifs_key *key,
3128 int lnum, int offs)
3129{
3130 struct ubifs_zbranch *zbr;
3131 struct ubifs_znode *znode, *zn;
3132 int n, found, err, nn;
3133 const int unique = !is_hash_key(c, key);
3134
3135 found = ubifs_lookup_level0(c, key, &znode, &n);
3136 if (found < 0)
3137 return found; /* Error code */
3138 if (!found)
3139 return 0;
3140 zbr = &znode->zbranch[n];
3141 if (lnum == zbr->lnum && offs == zbr->offs)
3142 return 1; /* Found it */
3143 if (unique)
3144 return 0;
3145 /*
3146 * Because the key is not unique, we have to look left
3147 * and right as well
3148 */
3149 zn = znode;
3150 nn = n;
3151 /* Look left */
3152 while (1) {
3153 err = tnc_prev(c, &znode, &n);
3154 if (err == -ENOENT)
3155 break;
3156 if (err)
3157 return err;
3158 if (keys_cmp(c, key, &znode->zbranch[n].key))
3159 break;
3160 zbr = &znode->zbranch[n];
3161 if (lnum == zbr->lnum && offs == zbr->offs)
3162 return 1; /* Found it */
3163 }
3164 /* Look right */
3165 znode = zn;
3166 n = nn;
3167 while (1) {
3168 err = tnc_next(c, &znode, &n);
3169 if (err) {
3170 if (err == -ENOENT)
3171 return 0;
3172 return err;
3173 }
3174 if (keys_cmp(c, key, &znode->zbranch[n].key))
3175 break;
3176 zbr = &znode->zbranch[n];
3177 if (lnum == zbr->lnum && offs == zbr->offs)
3178 return 1; /* Found it */
3179 }
3180 return 0;
3181}
3182
3183/**
3184 * ubifs_tnc_has_node - determine whether a node is in the TNC.
3185 * @c: UBIFS file-system description object
3186 * @key: node key
3187 * @level: index node level (if it is an index node)
3188 * @lnum: node LEB number
3189 * @offs: node offset
3190 * @is_idx: non-zero if the node is an index node
3191 *
3192 * This function returns %1 if the node is in the TNC, %0 if it is not, and a
3193 * negative error code in case of failure. For index nodes, @key has to be the
3194 * key of the first child. An index node is considered to be in the TNC only if
3195 * the corresponding znode is clean or has not been loaded.
3196 */
3197int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level,
3198 int lnum, int offs, int is_idx)
3199{
3200 int err;
3201
3202 mutex_lock(&c->tnc_mutex);
3203 if (is_idx) {
3204 err = is_idx_node_in_tnc(c, key, level, lnum, offs);
3205 if (err < 0)
3206 goto out_unlock;
3207 if (err == 1)
3208 /* The index node was found but it was dirty */
3209 err = 0;
3210 else if (err == 2)
3211 /* The index node was found and it was clean */
3212 err = 1;
3213 else
3214 BUG_ON(err != 0);
3215 } else
3216 err = is_leaf_node_in_tnc(c, key, lnum, offs);
3217
3218out_unlock:
3219 mutex_unlock(&c->tnc_mutex);
3220 return err;
3221}
3222
3223/**
3224 * ubifs_dirty_idx_node - dirty an index node.
3225 * @c: UBIFS file-system description object
3226 * @key: index node key
3227 * @level: index node level
3228 * @lnum: index node LEB number
3229 * @offs: index node offset
3230 *
3231 * This function loads and dirties an index node so that it can be garbage
3232 * collected. The @key argument has to be the key of the first child. This
3233 * function relies on the fact that 0:0 is never a valid LEB number and offset
3234 * for a main-area node. Returns %0 on success and a negative error code on
3235 * failure.
3236 */
3237int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level,
3238 int lnum, int offs)
3239{
3240 struct ubifs_znode *znode;
3241 int err = 0;
3242
3243 mutex_lock(&c->tnc_mutex);
3244 znode = lookup_znode(c, key, level, lnum, offs);
3245 if (!znode)
3246 goto out_unlock;
3247 if (IS_ERR(znode)) {
3248 err = PTR_ERR(znode);
3249 goto out_unlock;
3250 }
3251 znode = dirty_cow_bottom_up(c, znode);
3252 if (IS_ERR(znode)) {
3253 err = PTR_ERR(znode);
3254 goto out_unlock;
3255 }
3256
3257out_unlock:
3258 mutex_unlock(&c->tnc_mutex);
3259 return err;
3260}
Artem Bityutskiye3c3efc2009-08-27 16:34:19 +03003261
Artem Bityutskiye3c3efc2009-08-27 16:34:19 +03003262/**
3263 * dbg_check_inode_size - check if inode size is correct.
3264 * @c: UBIFS file-system description object
3265 * @inum: inode number
3266 * @size: inode size
3267 *
3268 * This function makes sure that the inode size (@size) is correct and it does
3269 * not have any pages beyond @size. Returns zero if the inode is OK, %-EINVAL
3270 * if it has a data page beyond @size, and other negative error code in case of
3271 * other errors.
3272 */
3273int dbg_check_inode_size(struct ubifs_info *c, const struct inode *inode,
3274 loff_t size)
3275{
3276 int err, n;
3277 union ubifs_key from_key, to_key, *key;
3278 struct ubifs_znode *znode;
3279 unsigned int block;
3280
3281 if (!S_ISREG(inode->i_mode))
3282 return 0;
Artem Bityutskiy2b1844a2011-06-03 08:31:29 +03003283 if (!dbg_is_chk_gen(c))
Artem Bityutskiye3c3efc2009-08-27 16:34:19 +03003284 return 0;
3285
3286 block = (size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT;
3287 data_key_init(c, &from_key, inode->i_ino, block);
3288 highest_data_key(c, &to_key, inode->i_ino);
3289
3290 mutex_lock(&c->tnc_mutex);
3291 err = ubifs_lookup_level0(c, &from_key, &znode, &n);
3292 if (err < 0)
3293 goto out_unlock;
3294
3295 if (err) {
Artem Bityutskiye3c3efc2009-08-27 16:34:19 +03003296 key = &from_key;
3297 goto out_dump;
3298 }
3299
3300 err = tnc_next(c, &znode, &n);
3301 if (err == -ENOENT) {
3302 err = 0;
3303 goto out_unlock;
3304 }
3305 if (err < 0)
3306 goto out_unlock;
3307
3308 ubifs_assert(err == 0);
3309 key = &znode->zbranch[n].key;
3310 if (!key_in_range(c, key, &from_key, &to_key))
3311 goto out_unlock;
3312
3313out_dump:
3314 block = key_block(c, key);
Sheng Yong235c3622015-03-20 10:39:42 +00003315 ubifs_err(c, "inode %lu has size %lld, but there are data at offset %lld",
Artem Bityutskiy515315a2012-01-13 12:33:53 +02003316 (unsigned long)inode->i_ino, size,
3317 ((loff_t)block) << UBIFS_BLOCK_SHIFT);
Artem Bityutskiy4315fb42011-05-25 17:32:42 +03003318 mutex_unlock(&c->tnc_mutex);
Artem Bityutskiyedf6be22012-05-16 19:15:56 +03003319 ubifs_dump_inode(c, inode);
Artem Bityutskiy7c46d0a2012-05-16 19:04:54 +03003320 dump_stack();
Artem Bityutskiy4315fb42011-05-25 17:32:42 +03003321 return -EINVAL;
Artem Bityutskiye3c3efc2009-08-27 16:34:19 +03003322
3323out_unlock:
3324 mutex_unlock(&c->tnc_mutex);
3325 return err;
3326}