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1/*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * Authors: Adrian Hunter
20 * Artem Bityutskiy (Битюцкий Артём)
21 */
22
23/*
24 * This file implements TNC (Tree Node Cache) which caches indexing nodes of
25 * the UBIFS B-tree.
26 *
27 * At the moment the locking rules of the TNC tree are quite simple and
28 * straightforward. We just have a mutex and lock it when we traverse the
29 * tree. If a znode is not in memory, we read it from flash while still having
30 * the mutex locked.
31 */
32
33#include <linux/crc32.h>
34#include <linux/slab.h>
35#include "ubifs.h"
36
37/*
38 * Returned codes of 'matches_name()' and 'fallible_matches_name()' functions.
39 * @NAME_LESS: name corresponding to the first argument is less than second
40 * @NAME_MATCHES: names match
41 * @NAME_GREATER: name corresponding to the second argument is greater than
42 * first
43 * @NOT_ON_MEDIA: node referred by zbranch does not exist on the media
44 *
45 * These constants were introduce to improve readability.
46 */
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 {
101 ubifs_err("old idx added twice!");
102 kfree(old_idx);
103 return 0;
104 }
105 }
106 rb_link_node(&old_idx->rb, parent, p);
107 rb_insert_color(&old_idx->rb, &c->old_idx);
108 return 0;
109}
110
111/**
112 * insert_old_idx_znode - record a znode obsoleted since last commit start.
113 * @c: UBIFS file-system description object
114 * @znode: znode of obsoleted index node
115 *
116 * Returns %0 on success, and a negative error code on failure.
117 */
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{
181 struct rb_node *this = c->old_idx.rb_node;
182 struct ubifs_old_idx *old_idx;
183
184 while (this) {
185 if (this->rb_left) {
186 this = this->rb_left;
187 continue;
188 } else if (this->rb_right) {
189 this = this->rb_right;
190 continue;
191 }
192 old_idx = rb_entry(this, struct ubifs_old_idx, rb);
193 this = rb_parent(this);
194 if (this) {
195 if (this->rb_left == &old_idx->rb)
196 this->rb_left = NULL;
197 else
198 this->rb_right = NULL;
199 }
200 kfree(old_idx);
201 }
202 c->old_idx = RB_ROOT;
203}
204
205/**
206 * copy_znode - copy a dirty znode.
207 * @c: UBIFS file-system description object
208 * @znode: znode to copy
209 *
210 * A dirty znode being committed may not be changed, so it is copied.
211 */
212static struct ubifs_znode *copy_znode(struct ubifs_info *c,
213 struct ubifs_znode *znode)
214{
215 struct ubifs_znode *zn;
216
217 zn = kmalloc(c->max_znode_sz, GFP_NOFS);
218 if (unlikely(!zn))
219 return ERR_PTR(-ENOMEM);
220
221 memcpy(zn, znode, c->max_znode_sz);
222 zn->cnext = NULL;
223 __set_bit(DIRTY_ZNODE, &zn->flags);
224 __clear_bit(COW_ZNODE, &zn->flags);
225
226 ubifs_assert(!ubifs_zn_obsolete(znode));
227 __set_bit(OBSOLETE_ZNODE, &znode->flags);
228
229 if (znode->level != 0) {
230 int i;
231 const int n = zn->child_cnt;
232
233 /* The children now have new parent */
234 for (i = 0; i < n; i++) {
235 struct ubifs_zbranch *zbr = &zn->zbranch[i];
236
237 if (zbr->znode)
238 zbr->znode->parent = zn;
239 }
240 }
241
242 atomic_long_inc(&c->dirty_zn_cnt);
243 return zn;
244}
245
246/**
247 * add_idx_dirt - add dirt due to a dirty znode.
248 * @c: UBIFS file-system description object
249 * @lnum: LEB number of index node
250 * @dirt: size of index node
251 *
252 * This function updates lprops dirty space and the new size of the index.
253 */
254static int add_idx_dirt(struct ubifs_info *c, int lnum, int dirt)
255{
256 c->calc_idx_sz -= ALIGN(dirt, 8);
257 return ubifs_add_dirt(c, lnum, dirt);
258}
259
260/**
261 * dirty_cow_znode - ensure a znode is not being committed.
262 * @c: UBIFS file-system description object
263 * @zbr: branch of znode to check
264 *
265 * Returns dirtied znode on success or negative error code on failure.
266 */
267static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c,
268 struct ubifs_zbranch *zbr)
269{
270 struct ubifs_znode *znode = zbr->znode;
271 struct ubifs_znode *zn;
272 int err;
273
274 if (!ubifs_zn_cow(znode)) {
275 /* znode is not being committed */
276 if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) {
277 atomic_long_inc(&c->dirty_zn_cnt);
278 atomic_long_dec(&c->clean_zn_cnt);
279 atomic_long_dec(&ubifs_clean_zn_cnt);
280 err = add_idx_dirt(c, zbr->lnum, zbr->len);
281 if (unlikely(err))
282 return ERR_PTR(err);
283 }
284 return znode;
285 }
286
287 zn = copy_znode(c, znode);
288 if (IS_ERR(zn))
289 return zn;
290
291 if (zbr->len) {
292 err = insert_old_idx(c, zbr->lnum, zbr->offs);
293 if (unlikely(err))
294 return ERR_PTR(err);
295 err = add_idx_dirt(c, zbr->lnum, zbr->len);
296 } else
297 err = 0;
298
299 zbr->znode = zn;
300 zbr->lnum = 0;
301 zbr->offs = 0;
302 zbr->len = 0;
303
304 if (unlikely(err))
305 return ERR_PTR(err);
306 return zn;
307}
308
309/**
310 * lnc_add - add a leaf node to the leaf node cache.
311 * @c: UBIFS file-system description object
312 * @zbr: zbranch of leaf node
313 * @node: leaf node
314 *
315 * Leaf nodes are non-index nodes directory entry nodes or data nodes. The
316 * purpose of the leaf node cache is to save re-reading the same leaf node over
317 * and over again. Most things are cached by VFS, however the file system must
318 * cache directory entries for readdir and for resolving hash collisions. The
319 * present implementation of the leaf node cache is extremely simple, and
320 * allows for error returns that are not used but that may be needed if a more
321 * complex implementation is created.
322 *
323 * Note, this function does not add the @node object to LNC directly, but
324 * allocates a copy of the object and adds the copy to LNC. The reason for this
325 * is that @node has been allocated outside of the TNC subsystem and will be
326 * used with @c->tnc_mutex unlock upon return from the TNC subsystem. But LNC
327 * may be changed at any time, e.g. freed by the shrinker.
328 */
329static int lnc_add(struct ubifs_info *c, struct ubifs_zbranch *zbr,
330 const void *node)
331{
332 int err;
333 void *lnc_node;
334 const struct ubifs_dent_node *dent = node;
335
336 ubifs_assert(!zbr->leaf);
337 ubifs_assert(zbr->len != 0);
338 ubifs_assert(is_hash_key(c, &zbr->key));
339
340 err = ubifs_validate_entry(c, dent);
341 if (err) {
342 dbg_dump_stack();
343 dbg_dump_node(c, dent);
344 return err;
345 }
346
347 lnc_node = kmalloc(zbr->len, GFP_NOFS);
348 if (!lnc_node)
349 /* We don't have to have the cache, so no error */
350 return 0;
351
352 memcpy(lnc_node, node, zbr->len);
353 zbr->leaf = lnc_node;
354 return 0;
355}
356
357 /**
358 * lnc_add_directly - add a leaf node to the leaf-node-cache.
359 * @c: UBIFS file-system description object
360 * @zbr: zbranch of leaf node
361 * @node: leaf node
362 *
363 * This function is similar to 'lnc_add()', but it does not create a copy of
364 * @node but inserts @node to TNC directly.
365 */
366static int lnc_add_directly(struct ubifs_info *c, struct ubifs_zbranch *zbr,
367 void *node)
368{
369 int err;
370
371 ubifs_assert(!zbr->leaf);
372 ubifs_assert(zbr->len != 0);
373
374 err = ubifs_validate_entry(c, node);
375 if (err) {
376 dbg_dump_stack();
377 dbg_dump_node(c, node);
378 return err;
379 }
380
381 zbr->leaf = node;
382 return 0;
383}
384
385/**
386 * lnc_free - remove a leaf node from the leaf node cache.
387 * @zbr: zbranch of leaf node
388 * @node: leaf node
389 */
390static void lnc_free(struct ubifs_zbranch *zbr)
391{
392 if (!zbr->leaf)
393 return;
394 kfree(zbr->leaf);
395 zbr->leaf = NULL;
396}
397
398/**
399 * tnc_read_node_nm - read a "hashed" leaf node.
400 * @c: UBIFS file-system description object
401 * @zbr: key and position of the node
402 * @node: node is returned here
403 *
404 * This function reads a "hashed" node defined by @zbr from the leaf node cache
405 * (in it is there) or from the hash media, in which case the node is also
406 * added to LNC. Returns zero in case of success or a negative negative error
407 * code in case of failure.
408 */
409static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr,
410 void *node)
411{
412 int err;
413
414 ubifs_assert(is_hash_key(c, &zbr->key));
415
416 if (zbr->leaf) {
417 /* Read from the leaf node cache */
418 ubifs_assert(zbr->len != 0);
419 memcpy(node, zbr->leaf, zbr->len);
420 return 0;
421 }
422
423 err = ubifs_tnc_read_node(c, zbr, node);
424 if (err)
425 return err;
426
427 /* Add the node to the leaf node cache */
428 err = lnc_add(c, zbr, node);
429 return err;
430}
431
432/**
433 * try_read_node - read a node if it is a node.
434 * @c: UBIFS file-system description object
435 * @buf: buffer to read to
436 * @type: node type
437 * @len: node length (not aligned)
438 * @lnum: LEB number of node to read
439 * @offs: offset of node to read
440 *
441 * This function tries to read a node of known type and length, checks it and
442 * stores it in @buf. This function returns %1 if a node is present and %0 if
443 * a node is not present. A negative error code is returned for I/O errors.
444 * This function performs that same function as ubifs_read_node except that
445 * it does not require that there is actually a node present and instead
446 * the return code indicates if a node was read.
447 *
448 * Note, this function does not check CRC of data nodes if @c->no_chk_data_crc
449 * is true (it is controlled by corresponding mount option). However, if
450 * @c->mounting or @c->remounting_rw is true (we are mounting or re-mounting to
451 * R/W mode), @c->no_chk_data_crc is ignored and CRC is checked. This is
452 * because during mounting or re-mounting from R/O mode to R/W mode we may read
453 * journal nodes (when replying the journal or doing the recovery) and the
454 * journal nodes may potentially be corrupted, so checking is required.
455 */
456static int try_read_node(const struct ubifs_info *c, void *buf, int type,
457 int len, int lnum, int offs)
458{
459 int err, node_len;
460 struct ubifs_ch *ch = buf;
461 uint32_t crc, node_crc;
462
463 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
464
465 err = ubifs_leb_read(c, lnum, buf, offs, len, 1);
466 if (err) {
467 ubifs_err("cannot read node type %d from LEB %d:%d, error %d",
468 type, lnum, offs, err);
469 return err;
470 }
471
472 if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC)
473 return 0;
474
475 if (ch->node_type != type)
476 return 0;
477
478 node_len = le32_to_cpu(ch->len);
479 if (node_len != len)
480 return 0;
481
482 if (type == UBIFS_DATA_NODE && c->no_chk_data_crc && !c->mounting &&
483 !c->remounting_rw)
484 return 1;
485
486 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
487 node_crc = le32_to_cpu(ch->crc);
488 if (crc != node_crc)
489 return 0;
490
491 return 1;
492}
493
494/**
495 * fallible_read_node - try to read a leaf node.
496 * @c: UBIFS file-system description object
497 * @key: key of node to read
498 * @zbr: position of node
499 * @node: node returned
500 *
501 * This function tries to read a node and returns %1 if the node is read, %0
502 * if the node is not present, and a negative error code in the case of error.
503 */
504static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
505 struct ubifs_zbranch *zbr, void *node)
506{
507 int ret;
508
509 dbg_tnc("LEB %d:%d, key %s", zbr->lnum, zbr->offs, DBGKEY(key));
510
511 ret = try_read_node(c, node, key_type(c, key), zbr->len, zbr->lnum,
512 zbr->offs);
513 if (ret == 1) {
514 union ubifs_key node_key;
515 struct ubifs_dent_node *dent = node;
516
517 /* All nodes have key in the same place */
518 key_read(c, &dent->key, &node_key);
519 if (keys_cmp(c, key, &node_key) != 0)
520 ret = 0;
521 }
522 if (ret == 0 && c->replaying)
523 dbg_mnt("dangling branch LEB %d:%d len %d, key %s",
524 zbr->lnum, zbr->offs, zbr->len, DBGKEY(key));
525 return ret;
526}
527
528/**
529 * matches_name - determine if a direntry or xattr entry matches a given name.
530 * @c: UBIFS file-system description object
531 * @zbr: zbranch of dent
532 * @nm: name to match
533 *
534 * This function checks if xentry/direntry referred by zbranch @zbr matches name
535 * @nm. Returns %NAME_MATCHES if it does, %NAME_LESS if the name referred by
536 * @zbr is less than @nm, and %NAME_GREATER if it is greater than @nm. In case
537 * of failure, a negative error code is returned.
538 */
539static int matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr,
540 const struct qstr *nm)
541{
542 struct ubifs_dent_node *dent;
543 int nlen, err;
544
545 /* If possible, match against the dent in the leaf node cache */
546 if (!zbr->leaf) {
547 dent = kmalloc(zbr->len, GFP_NOFS);
548 if (!dent)
549 return -ENOMEM;
550
551 err = ubifs_tnc_read_node(c, zbr, dent);
552 if (err)
553 goto out_free;
554
555 /* Add the node to the leaf node cache */
556 err = lnc_add_directly(c, zbr, dent);
557 if (err)
558 goto out_free;
559 } else
560 dent = zbr->leaf;
561
562 nlen = le16_to_cpu(dent->nlen);
563 err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
564 if (err == 0) {
565 if (nlen == nm->len)
566 return NAME_MATCHES;
567 else if (nlen < nm->len)
568 return NAME_LESS;
569 else
570 return NAME_GREATER;
571 } else if (err < 0)
572 return NAME_LESS;
573 else
574 return NAME_GREATER;
575
576out_free:
577 kfree(dent);
578 return err;
579}
580
581/**
582 * get_znode - get a TNC znode that may not be loaded yet.
583 * @c: UBIFS file-system description object
584 * @znode: parent znode
585 * @n: znode branch slot number
586 *
587 * This function returns the znode or a negative error code.
588 */
589static struct ubifs_znode *get_znode(struct ubifs_info *c,
590 struct ubifs_znode *znode, int n)
591{
592 struct ubifs_zbranch *zbr;
593
594 zbr = &znode->zbranch[n];
595 if (zbr->znode)
596 znode = zbr->znode;
597 else
598 znode = ubifs_load_znode(c, zbr, znode, n);
599 return znode;
600}
601
602/**
603 * tnc_next - find next TNC entry.
604 * @c: UBIFS file-system description object
605 * @zn: znode is passed and returned here
606 * @n: znode branch slot number is passed and returned here
607 *
608 * This function returns %0 if the next TNC entry is found, %-ENOENT if there is
609 * no next entry, or a negative error code otherwise.
610 */
611static int tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
612{
613 struct ubifs_znode *znode = *zn;
614 int nn = *n;
615
616 nn += 1;
617 if (nn < znode->child_cnt) {
618 *n = nn;
619 return 0;
620 }
621 while (1) {
622 struct ubifs_znode *zp;
623
624 zp = znode->parent;
625 if (!zp)
626 return -ENOENT;
627 nn = znode->iip + 1;
628 znode = zp;
629 if (nn < znode->child_cnt) {
630 znode = get_znode(c, znode, nn);
631 if (IS_ERR(znode))
632 return PTR_ERR(znode);
633 while (znode->level != 0) {
634 znode = get_znode(c, znode, 0);
635 if (IS_ERR(znode))
636 return PTR_ERR(znode);
637 }
638 nn = 0;
639 break;
640 }
641 }
642 *zn = znode;
643 *n = nn;
644 return 0;
645}
646
647/**
648 * tnc_prev - find previous TNC entry.
649 * @c: UBIFS file-system description object
650 * @zn: znode is returned here
651 * @n: znode branch slot number is passed and returned here
652 *
653 * This function returns %0 if the previous TNC entry is found, %-ENOENT if
654 * there is no next entry, or a negative error code otherwise.
655 */
656static int tnc_prev(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
657{
658 struct ubifs_znode *znode = *zn;
659 int nn = *n;
660
661 if (nn > 0) {
662 *n = nn - 1;
663 return 0;
664 }
665 while (1) {
666 struct ubifs_znode *zp;
667
668 zp = znode->parent;
669 if (!zp)
670 return -ENOENT;
671 nn = znode->iip - 1;
672 znode = zp;
673 if (nn >= 0) {
674 znode = get_znode(c, znode, nn);
675 if (IS_ERR(znode))
676 return PTR_ERR(znode);
677 while (znode->level != 0) {
678 nn = znode->child_cnt - 1;
679 znode = get_znode(c, znode, nn);
680 if (IS_ERR(znode))
681 return PTR_ERR(znode);
682 }
683 nn = znode->child_cnt - 1;
684 break;
685 }
686 }
687 *zn = znode;
688 *n = nn;
689 return 0;
690}
691
692/**
693 * resolve_collision - resolve a collision.
694 * @c: UBIFS file-system description object
695 * @key: key of a directory or extended attribute entry
696 * @zn: znode is returned here
697 * @n: zbranch number is passed and returned here
698 * @nm: name of the entry
699 *
700 * This function is called for "hashed" keys to make sure that the found key
701 * really corresponds to the looked up node (directory or extended attribute
702 * entry). It returns %1 and sets @zn and @n if the collision is resolved.
703 * %0 is returned if @nm is not found and @zn and @n are set to the previous
704 * entry, i.e. to the entry after which @nm could follow if it were in TNC.
705 * This means that @n may be set to %-1 if the leftmost key in @zn is the
706 * previous one. A negative error code is returned on failures.
707 */
708static int resolve_collision(struct ubifs_info *c, const union ubifs_key *key,
709 struct ubifs_znode **zn, int *n,
710 const struct qstr *nm)
711{
712 int err;
713
714 err = matches_name(c, &(*zn)->zbranch[*n], nm);
715 if (unlikely(err < 0))
716 return err;
717 if (err == NAME_MATCHES)
718 return 1;
719
720 if (err == NAME_GREATER) {
721 /* Look left */
722 while (1) {
723 err = tnc_prev(c, zn, n);
724 if (err == -ENOENT) {
725 ubifs_assert(*n == 0);
726 *n = -1;
727 return 0;
728 }
729 if (err < 0)
730 return err;
731 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
732 /*
733 * We have found the branch after which we would
734 * like to insert, but inserting in this znode
735 * may still be wrong. Consider the following 3
736 * znodes, in the case where we are resolving a
737 * collision with Key2.
738 *
739 * znode zp
740 * ----------------------
741 * level 1 | Key0 | Key1 |
742 * -----------------------
743 * | |
744 * znode za | | znode zb
745 * ------------ ------------
746 * level 0 | Key0 | | Key2 |
747 * ------------ ------------
748 *
749 * The lookup finds Key2 in znode zb. Lets say
750 * there is no match and the name is greater so
751 * we look left. When we find Key0, we end up
752 * here. If we return now, we will insert into
753 * znode za at slot n = 1. But that is invalid
754 * according to the parent's keys. Key2 must
755 * be inserted into znode zb.
756 *
757 * Note, this problem is not relevant for the
758 * case when we go right, because
759 * 'tnc_insert()' would correct the parent key.
760 */
761 if (*n == (*zn)->child_cnt - 1) {
762 err = tnc_next(c, zn, n);
763 if (err) {
764 /* Should be impossible */
765 ubifs_assert(0);
766 if (err == -ENOENT)
767 err = -EINVAL;
768 return err;
769 }
770 ubifs_assert(*n == 0);
771 *n = -1;
772 }
773 return 0;
774 }
775 err = matches_name(c, &(*zn)->zbranch[*n], nm);
776 if (err < 0)
777 return err;
778 if (err == NAME_LESS)
779 return 0;
780 if (err == NAME_MATCHES)
781 return 1;
782 ubifs_assert(err == NAME_GREATER);
783 }
784 } else {
785 int nn = *n;
786 struct ubifs_znode *znode = *zn;
787
788 /* Look right */
789 while (1) {
790 err = tnc_next(c, &znode, &nn);
791 if (err == -ENOENT)
792 return 0;
793 if (err < 0)
794 return err;
795 if (keys_cmp(c, &znode->zbranch[nn].key, key))
796 return 0;
797 err = matches_name(c, &znode->zbranch[nn], nm);
798 if (err < 0)
799 return err;
800 if (err == NAME_GREATER)
801 return 0;
802 *zn = znode;
803 *n = nn;
804 if (err == NAME_MATCHES)
805 return 1;
806 ubifs_assert(err == NAME_LESS);
807 }
808 }
809}
810
811/**
812 * fallible_matches_name - determine if a dent matches a given name.
813 * @c: UBIFS file-system description object
814 * @zbr: zbranch of dent
815 * @nm: name to match
816 *
817 * This is a "fallible" version of 'matches_name()' function which does not
818 * panic if the direntry/xentry referred by @zbr does not exist on the media.
819 *
820 * This function checks if xentry/direntry referred by zbranch @zbr matches name
821 * @nm. Returns %NAME_MATCHES it does, %NAME_LESS if the name referred by @zbr
822 * is less than @nm, %NAME_GREATER if it is greater than @nm, and @NOT_ON_MEDIA
823 * if xentry/direntry referred by @zbr does not exist on the media. A negative
824 * error code is returned in case of failure.
825 */
826static int fallible_matches_name(struct ubifs_info *c,
827 struct ubifs_zbranch *zbr,
828 const struct qstr *nm)
829{
830 struct ubifs_dent_node *dent;
831 int nlen, err;
832
833 /* If possible, match against the dent in the leaf node cache */
834 if (!zbr->leaf) {
835 dent = kmalloc(zbr->len, GFP_NOFS);
836 if (!dent)
837 return -ENOMEM;
838
839 err = fallible_read_node(c, &zbr->key, zbr, dent);
840 if (err < 0)
841 goto out_free;
842 if (err == 0) {
843 /* The node was not present */
844 err = NOT_ON_MEDIA;
845 goto out_free;
846 }
847 ubifs_assert(err == 1);
848
849 err = lnc_add_directly(c, zbr, dent);
850 if (err)
851 goto out_free;
852 } else
853 dent = zbr->leaf;
854
855 nlen = le16_to_cpu(dent->nlen);
856 err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
857 if (err == 0) {
858 if (nlen == nm->len)
859 return NAME_MATCHES;
860 else if (nlen < nm->len)
861 return NAME_LESS;
862 else
863 return NAME_GREATER;
864 } else if (err < 0)
865 return NAME_LESS;
866 else
867 return NAME_GREATER;
868
869out_free:
870 kfree(dent);
871 return err;
872}
873
874/**
875 * fallible_resolve_collision - resolve a collision even if nodes are missing.
876 * @c: UBIFS file-system description object
877 * @key: key
878 * @zn: znode is returned here
879 * @n: branch number is passed and returned here
880 * @nm: name of directory entry
881 * @adding: indicates caller is adding a key to the TNC
882 *
883 * This is a "fallible" version of the 'resolve_collision()' function which
884 * does not panic if one of the nodes referred to by TNC does not exist on the
885 * media. This may happen when replaying the journal if a deleted node was
886 * Garbage-collected and the commit was not done. A branch that refers to a node
887 * that is not present is called a dangling branch. The following are the return
888 * codes for this function:
889 * o if @nm was found, %1 is returned and @zn and @n are set to the found
890 * branch;
891 * o if we are @adding and @nm was not found, %0 is returned;
892 * o if we are not @adding and @nm was not found, but a dangling branch was
893 * found, then %1 is returned and @zn and @n are set to the dangling branch;
894 * o a negative error code is returned in case of failure.
895 */
896static int fallible_resolve_collision(struct ubifs_info *c,
897 const union ubifs_key *key,
898 struct ubifs_znode **zn, int *n,
899 const struct qstr *nm, int adding)
900{
901 struct ubifs_znode *o_znode = NULL, *znode = *zn;
902 int uninitialized_var(o_n), err, cmp, unsure = 0, nn = *n;
903
904 cmp = fallible_matches_name(c, &znode->zbranch[nn], nm);
905 if (unlikely(cmp < 0))
906 return cmp;
907 if (cmp == NAME_MATCHES)
908 return 1;
909 if (cmp == NOT_ON_MEDIA) {
910 o_znode = znode;
911 o_n = nn;
912 /*
913 * We are unlucky and hit a dangling branch straight away.
914 * Now we do not really know where to go to find the needed
915 * branch - to the left or to the right. Well, let's try left.
916 */
917 unsure = 1;
918 } else if (!adding)
919 unsure = 1; /* Remove a dangling branch wherever it is */
920
921 if (cmp == NAME_GREATER || unsure) {
922 /* Look left */
923 while (1) {
924 err = tnc_prev(c, zn, n);
925 if (err == -ENOENT) {
926 ubifs_assert(*n == 0);
927 *n = -1;
928 break;
929 }
930 if (err < 0)
931 return err;
932 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
933 /* See comments in 'resolve_collision()' */
934 if (*n == (*zn)->child_cnt - 1) {
935 err = tnc_next(c, zn, n);
936 if (err) {
937 /* Should be impossible */
938 ubifs_assert(0);
939 if (err == -ENOENT)
940 err = -EINVAL;
941 return err;
942 }
943 ubifs_assert(*n == 0);
944 *n = -1;
945 }
946 break;
947 }
948 err = fallible_matches_name(c, &(*zn)->zbranch[*n], nm);
949 if (err < 0)
950 return err;
951 if (err == NAME_MATCHES)
952 return 1;
953 if (err == NOT_ON_MEDIA) {
954 o_znode = *zn;
955 o_n = *n;
956 continue;
957 }
958 if (!adding)
959 continue;
960 if (err == NAME_LESS)
961 break;
962 else
963 unsure = 0;
964 }
965 }
966
967 if (cmp == NAME_LESS || unsure) {
968 /* Look right */
969 *zn = znode;
970 *n = nn;
971 while (1) {
972 err = tnc_next(c, &znode, &nn);
973 if (err == -ENOENT)
974 break;
975 if (err < 0)
976 return err;
977 if (keys_cmp(c, &znode->zbranch[nn].key, key))
978 break;
979 err = fallible_matches_name(c, &znode->zbranch[nn], nm);
980 if (err < 0)
981 return err;
982 if (err == NAME_GREATER)
983 break;
984 *zn = znode;
985 *n = nn;
986 if (err == NAME_MATCHES)
987 return 1;
988 if (err == NOT_ON_MEDIA) {
989 o_znode = znode;
990 o_n = nn;
991 }
992 }
993 }
994
995 /* Never match a dangling branch when adding */
996 if (adding || !o_znode)
997 return 0;
998
999 dbg_mnt("dangling match LEB %d:%d len %d %s",
1000 o_znode->zbranch[o_n].lnum, o_znode->zbranch[o_n].offs,
1001 o_znode->zbranch[o_n].len, DBGKEY(key));
1002 *zn = o_znode;
1003 *n = o_n;
1004 return 1;
1005}
1006
1007/**
1008 * matches_position - determine if a zbranch matches a given position.
1009 * @zbr: zbranch of dent
1010 * @lnum: LEB number of dent to match
1011 * @offs: offset of dent to match
1012 *
1013 * This function returns %1 if @lnum:@offs matches, and %0 otherwise.
1014 */
1015static int matches_position(struct ubifs_zbranch *zbr, int lnum, int offs)
1016{
1017 if (zbr->lnum == lnum && zbr->offs == offs)
1018 return 1;
1019 else
1020 return 0;
1021}
1022
1023/**
1024 * resolve_collision_directly - resolve a collision directly.
1025 * @c: UBIFS file-system description object
1026 * @key: key of directory entry
1027 * @zn: znode is passed and returned here
1028 * @n: zbranch number is passed and returned here
1029 * @lnum: LEB number of dent node to match
1030 * @offs: offset of dent node to match
1031 *
1032 * This function is used for "hashed" keys to make sure the found directory or
1033 * extended attribute entry node is what was looked for. It is used when the
1034 * flash address of the right node is known (@lnum:@offs) which makes it much
1035 * easier to resolve collisions (no need to read entries and match full
1036 * names). This function returns %1 and sets @zn and @n if the collision is
1037 * resolved, %0 if @lnum:@offs is not found and @zn and @n are set to the
1038 * previous directory entry. Otherwise a negative error code is returned.
1039 */
1040static int resolve_collision_directly(struct ubifs_info *c,
1041 const union ubifs_key *key,
1042 struct ubifs_znode **zn, int *n,
1043 int lnum, int offs)
1044{
1045 struct ubifs_znode *znode;
1046 int nn, err;
1047
1048 znode = *zn;
1049 nn = *n;
1050 if (matches_position(&znode->zbranch[nn], lnum, offs))
1051 return 1;
1052
1053 /* Look left */
1054 while (1) {
1055 err = tnc_prev(c, &znode, &nn);
1056 if (err == -ENOENT)
1057 break;
1058 if (err < 0)
1059 return err;
1060 if (keys_cmp(c, &znode->zbranch[nn].key, key))
1061 break;
1062 if (matches_position(&znode->zbranch[nn], lnum, offs)) {
1063 *zn = znode;
1064 *n = nn;
1065 return 1;
1066 }
1067 }
1068
1069 /* Look right */
1070 znode = *zn;
1071 nn = *n;
1072 while (1) {
1073 err = tnc_next(c, &znode, &nn);
1074 if (err == -ENOENT)
1075 return 0;
1076 if (err < 0)
1077 return err;
1078 if (keys_cmp(c, &znode->zbranch[nn].key, key))
1079 return 0;
1080 *zn = znode;
1081 *n = nn;
1082 if (matches_position(&znode->zbranch[nn], lnum, offs))
1083 return 1;
1084 }
1085}
1086
1087/**
1088 * dirty_cow_bottom_up - dirty a znode and its ancestors.
1089 * @c: UBIFS file-system description object
1090 * @znode: znode to dirty
1091 *
1092 * If we do not have a unique key that resides in a znode, then we cannot
1093 * dirty that znode from the top down (i.e. by using lookup_level0_dirty)
1094 * This function records the path back to the last dirty ancestor, and then
1095 * dirties the znodes on that path.
1096 */
1097static struct ubifs_znode *dirty_cow_bottom_up(struct ubifs_info *c,
1098 struct ubifs_znode *znode)
1099{
1100 struct ubifs_znode *zp;
1101 int *path = c->bottom_up_buf, p = 0;
1102
1103 ubifs_assert(c->zroot.znode);
1104 ubifs_assert(znode);
1105 if (c->zroot.znode->level > BOTTOM_UP_HEIGHT) {
1106 kfree(c->bottom_up_buf);
1107 c->bottom_up_buf = kmalloc(c->zroot.znode->level * sizeof(int),
1108 GFP_NOFS);
1109 if (!c->bottom_up_buf)
1110 return ERR_PTR(-ENOMEM);
1111 path = c->bottom_up_buf;
1112 }
1113 if (c->zroot.znode->level) {
1114 /* Go up until parent is dirty */
1115 while (1) {
1116 int n;
1117
1118 zp = znode->parent;
1119 if (!zp)
1120 break;
1121 n = znode->iip;
1122 ubifs_assert(p < c->zroot.znode->level);
1123 path[p++] = n;
1124 if (!zp->cnext && ubifs_zn_dirty(znode))
1125 break;
1126 znode = zp;
1127 }
1128 }
1129
1130 /* Come back down, dirtying as we go */
1131 while (1) {
1132 struct ubifs_zbranch *zbr;
1133
1134 zp = znode->parent;
1135 if (zp) {
1136 ubifs_assert(path[p - 1] >= 0);
1137 ubifs_assert(path[p - 1] < zp->child_cnt);
1138 zbr = &zp->zbranch[path[--p]];
1139 znode = dirty_cow_znode(c, zbr);
1140 } else {
1141 ubifs_assert(znode == c->zroot.znode);
1142 znode = dirty_cow_znode(c, &c->zroot);
1143 }
1144 if (IS_ERR(znode) || !p)
1145 break;
1146 ubifs_assert(path[p - 1] >= 0);
1147 ubifs_assert(path[p - 1] < znode->child_cnt);
1148 znode = znode->zbranch[path[p - 1]].znode;
1149 }
1150
1151 return znode;
1152}
1153
1154/**
1155 * ubifs_lookup_level0 - search for zero-level znode.
1156 * @c: UBIFS file-system description object
1157 * @key: key to lookup
1158 * @zn: znode is returned here
1159 * @n: znode branch slot number is returned here
1160 *
1161 * This function looks up the TNC tree and search for zero-level znode which
1162 * refers key @key. The found zero-level znode is returned in @zn. There are 3
1163 * cases:
1164 * o exact match, i.e. the found zero-level znode contains key @key, then %1
1165 * is returned and slot number of the matched branch is stored in @n;
1166 * o not exact match, which means that zero-level znode does not contain
1167 * @key, then %0 is returned and slot number of the closest branch is stored
1168 * in @n;
1169 * o @key is so small that it is even less than the lowest key of the
1170 * leftmost zero-level node, then %0 is returned and %0 is stored in @n.
1171 *
1172 * Note, when the TNC tree is traversed, some znodes may be absent, then this
1173 * function reads corresponding indexing nodes and inserts them to TNC. In
1174 * case of failure, a negative error code is returned.
1175 */
1176int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
1177 struct ubifs_znode **zn, int *n)
1178{
1179 int err, exact;
1180 struct ubifs_znode *znode;
1181 unsigned long time = get_seconds();
1182
1183 dbg_tnc("search key %s", DBGKEY(key));
1184 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
1185
1186 znode = c->zroot.znode;
1187 if (unlikely(!znode)) {
1188 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
1189 if (IS_ERR(znode))
1190 return PTR_ERR(znode);
1191 }
1192
1193 znode->time = time;
1194
1195 while (1) {
1196 struct ubifs_zbranch *zbr;
1197
1198 exact = ubifs_search_zbranch(c, znode, key, n);
1199
1200 if (znode->level == 0)
1201 break;
1202
1203 if (*n < 0)
1204 *n = 0;
1205 zbr = &znode->zbranch[*n];
1206
1207 if (zbr->znode) {
1208 znode->time = time;
1209 znode = zbr->znode;
1210 continue;
1211 }
1212
1213 /* znode is not in TNC cache, load it from the media */
1214 znode = ubifs_load_znode(c, zbr, znode, *n);
1215 if (IS_ERR(znode))
1216 return PTR_ERR(znode);
1217 }
1218
1219 *zn = znode;
1220 if (exact || !is_hash_key(c, key) || *n != -1) {
1221 dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
1222 return exact;
1223 }
1224
1225 /*
1226 * Here is a tricky place. We have not found the key and this is a
1227 * "hashed" key, which may collide. The rest of the code deals with
1228 * situations like this:
1229 *
1230 * | 3 | 5 |
1231 * / \
1232 * | 3 | 5 | | 6 | 7 | (x)
1233 *
1234 * Or more a complex example:
1235 *
1236 * | 1 | 5 |
1237 * / \
1238 * | 1 | 3 | | 5 | 8 |
1239 * \ /
1240 * | 5 | 5 | | 6 | 7 | (x)
1241 *
1242 * In the examples, if we are looking for key "5", we may reach nodes
1243 * marked with "(x)". In this case what we have do is to look at the
1244 * left and see if there is "5" key there. If there is, we have to
1245 * return it.
1246 *
1247 * Note, this whole situation is possible because we allow to have
1248 * elements which are equivalent to the next key in the parent in the
1249 * children of current znode. For example, this happens if we split a
1250 * znode like this: | 3 | 5 | 5 | 6 | 7 |, which results in something
1251 * like this:
1252 * | 3 | 5 |
1253 * / \
1254 * | 3 | 5 | | 5 | 6 | 7 |
1255 * ^
1256 * And this becomes what is at the first "picture" after key "5" marked
1257 * with "^" is removed. What could be done is we could prohibit
1258 * splitting in the middle of the colliding sequence. Also, when
1259 * removing the leftmost key, we would have to correct the key of the
1260 * parent node, which would introduce additional complications. Namely,
1261 * if we changed the leftmost key of the parent znode, the garbage
1262 * collector would be unable to find it (GC is doing this when GC'ing
1263 * indexing LEBs). Although we already have an additional RB-tree where
1264 * we save such changed znodes (see 'ins_clr_old_idx_znode()') until
1265 * after the commit. But anyway, this does not look easy to implement
1266 * so we did not try this.
1267 */
1268 err = tnc_prev(c, &znode, n);
1269 if (err == -ENOENT) {
1270 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1271 *n = -1;
1272 return 0;
1273 }
1274 if (unlikely(err < 0))
1275 return err;
1276 if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
1277 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1278 *n = -1;
1279 return 0;
1280 }
1281
1282 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1283 *zn = znode;
1284 return 1;
1285}
1286
1287/**
1288 * lookup_level0_dirty - search for zero-level znode dirtying.
1289 * @c: UBIFS file-system description object
1290 * @key: key to lookup
1291 * @zn: znode is returned here
1292 * @n: znode branch slot number is returned here
1293 *
1294 * This function looks up the TNC tree and search for zero-level znode which
1295 * refers key @key. The found zero-level znode is returned in @zn. There are 3
1296 * cases:
1297 * o exact match, i.e. the found zero-level znode contains key @key, then %1
1298 * is returned and slot number of the matched branch is stored in @n;
1299 * o not exact match, which means that zero-level znode does not contain @key
1300 * then %0 is returned and slot number of the closed branch is stored in
1301 * @n;
1302 * o @key is so small that it is even less than the lowest key of the
1303 * leftmost zero-level node, then %0 is returned and %-1 is stored in @n.
1304 *
1305 * Additionally all znodes in the path from the root to the located zero-level
1306 * znode are marked as dirty.
1307 *
1308 * Note, when the TNC tree is traversed, some znodes may be absent, then this
1309 * function reads corresponding indexing nodes and inserts them to TNC. In
1310 * case of failure, a negative error code is returned.
1311 */
1312static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key,
1313 struct ubifs_znode **zn, int *n)
1314{
1315 int err, exact;
1316 struct ubifs_znode *znode;
1317 unsigned long time = get_seconds();
1318
1319 dbg_tnc("search and dirty key %s", DBGKEY(key));
1320
1321 znode = c->zroot.znode;
1322 if (unlikely(!znode)) {
1323 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
1324 if (IS_ERR(znode))
1325 return PTR_ERR(znode);
1326 }
1327
1328 znode = dirty_cow_znode(c, &c->zroot);
1329 if (IS_ERR(znode))
1330 return PTR_ERR(znode);
1331
1332 znode->time = time;
1333
1334 while (1) {
1335 struct ubifs_zbranch *zbr;
1336
1337 exact = ubifs_search_zbranch(c, znode, key, n);
1338
1339 if (znode->level == 0)
1340 break;
1341
1342 if (*n < 0)
1343 *n = 0;
1344 zbr = &znode->zbranch[*n];
1345
1346 if (zbr->znode) {
1347 znode->time = time;
1348 znode = dirty_cow_znode(c, zbr);
1349 if (IS_ERR(znode))
1350 return PTR_ERR(znode);
1351 continue;
1352 }
1353
1354 /* znode is not in TNC cache, load it from the media */
1355 znode = ubifs_load_znode(c, zbr, znode, *n);
1356 if (IS_ERR(znode))
1357 return PTR_ERR(znode);
1358 znode = dirty_cow_znode(c, zbr);
1359 if (IS_ERR(znode))
1360 return PTR_ERR(znode);
1361 }
1362
1363 *zn = znode;
1364 if (exact || !is_hash_key(c, key) || *n != -1) {
1365 dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
1366 return exact;
1367 }
1368
1369 /*
1370 * See huge comment at 'lookup_level0_dirty()' what is the rest of the
1371 * code.
1372 */
1373 err = tnc_prev(c, &znode, n);
1374 if (err == -ENOENT) {
1375 *n = -1;
1376 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1377 return 0;
1378 }
1379 if (unlikely(err < 0))
1380 return err;
1381 if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
1382 *n = -1;
1383 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1384 return 0;
1385 }
1386
1387 if (znode->cnext || !ubifs_zn_dirty(znode)) {
1388 znode = dirty_cow_bottom_up(c, znode);
1389 if (IS_ERR(znode))
1390 return PTR_ERR(znode);
1391 }
1392
1393 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1394 *zn = znode;
1395 return 1;
1396}
1397
1398/**
1399 * maybe_leb_gced - determine if a LEB may have been garbage collected.
1400 * @c: UBIFS file-system description object
1401 * @lnum: LEB number
1402 * @gc_seq1: garbage collection sequence number
1403 *
1404 * This function determines if @lnum may have been garbage collected since
1405 * sequence number @gc_seq1. If it may have been then %1 is returned, otherwise
1406 * %0 is returned.
1407 */
1408static int maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1)
1409{
1410 int gc_seq2, gced_lnum;
1411
1412 gced_lnum = c->gced_lnum;
1413 smp_rmb();
1414 gc_seq2 = c->gc_seq;
1415 /* Same seq means no GC */
1416 if (gc_seq1 == gc_seq2)
1417 return 0;
1418 /* Different by more than 1 means we don't know */
1419 if (gc_seq1 + 1 != gc_seq2)
1420 return 1;
1421 /*
1422 * We have seen the sequence number has increased by 1. Now we need to
1423 * be sure we read the right LEB number, so read it again.
1424 */
1425 smp_rmb();
1426 if (gced_lnum != c->gced_lnum)
1427 return 1;
1428 /* Finally we can check lnum */
1429 if (gced_lnum == lnum)
1430 return 1;
1431 return 0;
1432}
1433
1434/**
1435 * ubifs_tnc_locate - look up a file-system node and return it and its location.
1436 * @c: UBIFS file-system description object
1437 * @key: node key to lookup
1438 * @node: the node is returned here
1439 * @lnum: LEB number is returned here
1440 * @offs: offset is returned here
1441 *
1442 * This function looks up and reads node with key @key. The caller has to make
1443 * sure the @node buffer is large enough to fit the node. Returns zero in case
1444 * of success, %-ENOENT if the node was not found, and a negative error code in
1445 * case of failure. The node location can be returned in @lnum and @offs.
1446 */
1447int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key,
1448 void *node, int *lnum, int *offs)
1449{
1450 int found, n, err, safely = 0, gc_seq1;
1451 struct ubifs_znode *znode;
1452 struct ubifs_zbranch zbr, *zt;
1453
1454again:
1455 mutex_lock(&c->tnc_mutex);
1456 found = ubifs_lookup_level0(c, key, &znode, &n);
1457 if (!found) {
1458 err = -ENOENT;
1459 goto out;
1460 } else if (found < 0) {
1461 err = found;
1462 goto out;
1463 }
1464 zt = &znode->zbranch[n];
1465 if (lnum) {
1466 *lnum = zt->lnum;
1467 *offs = zt->offs;
1468 }
1469 if (is_hash_key(c, key)) {
1470 /*
1471 * In this case the leaf node cache gets used, so we pass the
1472 * address of the zbranch and keep the mutex locked
1473 */
1474 err = tnc_read_node_nm(c, zt, node);
1475 goto out;
1476 }
1477 if (safely) {
1478 err = ubifs_tnc_read_node(c, zt, node);
1479 goto out;
1480 }
1481 /* Drop the TNC mutex prematurely and race with garbage collection */
1482 zbr = znode->zbranch[n];
1483 gc_seq1 = c->gc_seq;
1484 mutex_unlock(&c->tnc_mutex);
1485
1486 if (ubifs_get_wbuf(c, zbr.lnum)) {
1487 /* We do not GC journal heads */
1488 err = ubifs_tnc_read_node(c, &zbr, node);
1489 return err;
1490 }
1491
1492 err = fallible_read_node(c, key, &zbr, node);
1493 if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) {
1494 /*
1495 * The node may have been GC'ed out from under us so try again
1496 * while keeping the TNC mutex locked.
1497 */
1498 safely = 1;
1499 goto again;
1500 }
1501 return 0;
1502
1503out:
1504 mutex_unlock(&c->tnc_mutex);
1505 return err;
1506}
1507
1508/**
1509 * ubifs_tnc_get_bu_keys - lookup keys for bulk-read.
1510 * @c: UBIFS file-system description object
1511 * @bu: bulk-read parameters and results
1512 *
1513 * Lookup consecutive data node keys for the same inode that reside
1514 * consecutively in the same LEB. This function returns zero in case of success
1515 * and a negative error code in case of failure.
1516 *
1517 * Note, if the bulk-read buffer length (@bu->buf_len) is known, this function
1518 * makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares
1519 * maximum possible amount of nodes for bulk-read.
1520 */
1521int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)
1522{
1523 int n, err = 0, lnum = -1, uninitialized_var(offs);
1524 int uninitialized_var(len);
1525 unsigned int block = key_block(c, &bu->key);
1526 struct ubifs_znode *znode;
1527
1528 bu->cnt = 0;
1529 bu->blk_cnt = 0;
1530 bu->eof = 0;
1531
1532 mutex_lock(&c->tnc_mutex);
1533 /* Find first key */
1534 err = ubifs_lookup_level0(c, &bu->key, &znode, &n);
1535 if (err < 0)
1536 goto out;
1537 if (err) {
1538 /* Key found */
1539 len = znode->zbranch[n].len;
1540 /* The buffer must be big enough for at least 1 node */
1541 if (len > bu->buf_len) {
1542 err = -EINVAL;
1543 goto out;
1544 }
1545 /* Add this key */
1546 bu->zbranch[bu->cnt++] = znode->zbranch[n];
1547 bu->blk_cnt += 1;
1548 lnum = znode->zbranch[n].lnum;
1549 offs = ALIGN(znode->zbranch[n].offs + len, 8);
1550 }
1551 while (1) {
1552 struct ubifs_zbranch *zbr;
1553 union ubifs_key *key;
1554 unsigned int next_block;
1555
1556 /* Find next key */
1557 err = tnc_next(c, &znode, &n);
1558 if (err)
1559 goto out;
1560 zbr = &znode->zbranch[n];
1561 key = &zbr->key;
1562 /* See if there is another data key for this file */
1563 if (key_inum(c, key) != key_inum(c, &bu->key) ||
1564 key_type(c, key) != UBIFS_DATA_KEY) {
1565 err = -ENOENT;
1566 goto out;
1567 }
1568 if (lnum < 0) {
1569 /* First key found */
1570 lnum = zbr->lnum;
1571 offs = ALIGN(zbr->offs + zbr->len, 8);
1572 len = zbr->len;
1573 if (len > bu->buf_len) {
1574 err = -EINVAL;
1575 goto out;
1576 }
1577 } else {
1578 /*
1579 * The data nodes must be in consecutive positions in
1580 * the same LEB.
1581 */
1582 if (zbr->lnum != lnum || zbr->offs != offs)
1583 goto out;
1584 offs += ALIGN(zbr->len, 8);
1585 len = ALIGN(len, 8) + zbr->len;
1586 /* Must not exceed buffer length */
1587 if (len > bu->buf_len)
1588 goto out;
1589 }
1590 /* Allow for holes */
1591 next_block = key_block(c, key);
1592 bu->blk_cnt += (next_block - block - 1);
1593 if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
1594 goto out;
1595 block = next_block;
1596 /* Add this key */
1597 bu->zbranch[bu->cnt++] = *zbr;
1598 bu->blk_cnt += 1;
1599 /* See if we have room for more */
1600 if (bu->cnt >= UBIFS_MAX_BULK_READ)
1601 goto out;
1602 if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
1603 goto out;
1604 }
1605out:
1606 if (err == -ENOENT) {
1607 bu->eof = 1;
1608 err = 0;
1609 }
1610 bu->gc_seq = c->gc_seq;
1611 mutex_unlock(&c->tnc_mutex);
1612 if (err)
1613 return err;
1614 /*
1615 * An enormous hole could cause bulk-read to encompass too many
1616 * page cache pages, so limit the number here.
1617 */
1618 if (bu->blk_cnt > UBIFS_MAX_BULK_READ)
1619 bu->blk_cnt = UBIFS_MAX_BULK_READ;
1620 /*
1621 * Ensure that bulk-read covers a whole number of page cache
1622 * pages.
1623 */
1624 if (UBIFS_BLOCKS_PER_PAGE == 1 ||
1625 !(bu->blk_cnt & (UBIFS_BLOCKS_PER_PAGE - 1)))
1626 return 0;
1627 if (bu->eof) {
1628 /* At the end of file we can round up */
1629 bu->blk_cnt += UBIFS_BLOCKS_PER_PAGE - 1;
1630 return 0;
1631 }
1632 /* Exclude data nodes that do not make up a whole page cache page */
1633 block = key_block(c, &bu->key) + bu->blk_cnt;
1634 block &= ~(UBIFS_BLOCKS_PER_PAGE - 1);
1635 while (bu->cnt) {
1636 if (key_block(c, &bu->zbranch[bu->cnt - 1].key) < block)
1637 break;
1638 bu->cnt -= 1;
1639 }
1640 return 0;
1641}
1642
1643/**
1644 * read_wbuf - bulk-read from a LEB with a wbuf.
1645 * @wbuf: wbuf that may overlap the read
1646 * @buf: buffer into which to read
1647 * @len: read length
1648 * @lnum: LEB number from which to read
1649 * @offs: offset from which to read
1650 *
1651 * This functions returns %0 on success or a negative error code on failure.
1652 */
1653static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum,
1654 int offs)
1655{
1656 const struct ubifs_info *c = wbuf->c;
1657 int rlen, overlap;
1658
1659 dbg_io("LEB %d:%d, length %d", lnum, offs, len);
1660 ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
1661 ubifs_assert(!(offs & 7) && offs < c->leb_size);
1662 ubifs_assert(offs + len <= c->leb_size);
1663
1664 spin_lock(&wbuf->lock);
1665 overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
1666 if (!overlap) {
1667 /* We may safely unlock the write-buffer and read the data */
1668 spin_unlock(&wbuf->lock);
1669 return ubifs_leb_read(c, lnum, buf, offs, len, 0);
1670 }
1671
1672 /* Don't read under wbuf */
1673 rlen = wbuf->offs - offs;
1674 if (rlen < 0)
1675 rlen = 0;
1676
1677 /* Copy the rest from the write-buffer */
1678 memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
1679 spin_unlock(&wbuf->lock);
1680
1681 if (rlen > 0)
1682 /* Read everything that goes before write-buffer */
1683 return ubifs_leb_read(c, lnum, buf, offs, rlen, 0);
1684
1685 return 0;
1686}
1687
1688/**
1689 * validate_data_node - validate data nodes for bulk-read.
1690 * @c: UBIFS file-system description object
1691 * @buf: buffer containing data node to validate
1692 * @zbr: zbranch of data node to validate
1693 *
1694 * This functions returns %0 on success or a negative error code on failure.
1695 */
1696static int validate_data_node(struct ubifs_info *c, void *buf,
1697 struct ubifs_zbranch *zbr)
1698{
1699 union ubifs_key key1;
1700 struct ubifs_ch *ch = buf;
1701 int err, len;
1702
1703 if (ch->node_type != UBIFS_DATA_NODE) {
1704 ubifs_err("bad node type (%d but expected %d)",
1705 ch->node_type, UBIFS_DATA_NODE);
1706 goto out_err;
1707 }
1708
1709 err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0, 0);
1710 if (err) {
1711 ubifs_err("expected node type %d", UBIFS_DATA_NODE);
1712 goto out;
1713 }
1714
1715 len = le32_to_cpu(ch->len);
1716 if (len != zbr->len) {
1717 ubifs_err("bad node length %d, expected %d", len, zbr->len);
1718 goto out_err;
1719 }
1720
1721 /* Make sure the key of the read node is correct */
1722 key_read(c, buf + UBIFS_KEY_OFFSET, &key1);
1723 if (!keys_eq(c, &zbr->key, &key1)) {
1724 ubifs_err("bad key in node at LEB %d:%d",
1725 zbr->lnum, zbr->offs);
1726 dbg_tnc("looked for key %s found node's key %s",
1727 DBGKEY(&zbr->key), DBGKEY1(&key1));
1728 goto out_err;
1729 }
1730
1731 return 0;
1732
1733out_err:
1734 err = -EINVAL;
1735out:
1736 ubifs_err("bad node at LEB %d:%d", zbr->lnum, zbr->offs);
1737 dbg_dump_node(c, buf);
1738 dbg_dump_stack();
1739 return err;
1740}
1741
1742/**
1743 * ubifs_tnc_bulk_read - read a number of data nodes in one go.
1744 * @c: UBIFS file-system description object
1745 * @bu: bulk-read parameters and results
1746 *
1747 * This functions reads and validates the data nodes that were identified by the
1748 * 'ubifs_tnc_get_bu_keys()' function. This functions returns %0 on success,
1749 * -EAGAIN to indicate a race with GC, or another negative error code on
1750 * failure.
1751 */
1752int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu)
1753{
1754 int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i;
1755 struct ubifs_wbuf *wbuf;
1756 void *buf;
1757
1758 len = bu->zbranch[bu->cnt - 1].offs;
1759 len += bu->zbranch[bu->cnt - 1].len - offs;
1760 if (len > bu->buf_len) {
1761 ubifs_err("buffer too small %d vs %d", bu->buf_len, len);
1762 return -EINVAL;
1763 }
1764
1765 /* Do the read */
1766 wbuf = ubifs_get_wbuf(c, lnum);
1767 if (wbuf)
1768 err = read_wbuf(wbuf, bu->buf, len, lnum, offs);
1769 else
1770 err = ubifs_leb_read(c, lnum, bu->buf, offs, len, 0);
1771
1772 /* Check for a race with GC */
1773 if (maybe_leb_gced(c, lnum, bu->gc_seq))
1774 return -EAGAIN;
1775
1776 if (err && err != -EBADMSG) {
1777 ubifs_err("failed to read from LEB %d:%d, error %d",
1778 lnum, offs, err);
1779 dbg_dump_stack();
1780 dbg_tnc("key %s", DBGKEY(&bu->key));
1781 return err;
1782 }
1783
1784 /* Validate the nodes read */
1785 buf = bu->buf;
1786 for (i = 0; i < bu->cnt; i++) {
1787 err = validate_data_node(c, buf, &bu->zbranch[i]);
1788 if (err)
1789 return err;
1790 buf = buf + ALIGN(bu->zbranch[i].len, 8);
1791 }
1792
1793 return 0;
1794}
1795
1796/**
1797 * do_lookup_nm- look up a "hashed" node.
1798 * @c: UBIFS file-system description object
1799 * @key: node key to lookup
1800 * @node: the node is returned here
1801 * @nm: node name
1802 *
1803 * This function look up and reads a node which contains name hash in the key.
1804 * Since the hash may have collisions, there may be many nodes with the same
1805 * key, so we have to sequentially look to all of them until the needed one is
1806 * found. This function returns zero in case of success, %-ENOENT if the node
1807 * was not found, and a negative error code in case of failure.
1808 */
1809static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1810 void *node, const struct qstr *nm)
1811{
1812 int found, n, err;
1813 struct ubifs_znode *znode;
1814
1815 dbg_tnc("name '%.*s' key %s", nm->len, nm->name, DBGKEY(key));
1816 mutex_lock(&c->tnc_mutex);
1817 found = ubifs_lookup_level0(c, key, &znode, &n);
1818 if (!found) {
1819 err = -ENOENT;
1820 goto out_unlock;
1821 } else if (found < 0) {
1822 err = found;
1823 goto out_unlock;
1824 }
1825
1826 ubifs_assert(n >= 0);
1827
1828 err = resolve_collision(c, key, &znode, &n, nm);
1829 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
1830 if (unlikely(err < 0))
1831 goto out_unlock;
1832 if (err == 0) {
1833 err = -ENOENT;
1834 goto out_unlock;
1835 }
1836
1837 err = tnc_read_node_nm(c, &znode->zbranch[n], node);
1838
1839out_unlock:
1840 mutex_unlock(&c->tnc_mutex);
1841 return err;
1842}
1843
1844/**
1845 * ubifs_tnc_lookup_nm - look up a "hashed" node.
1846 * @c: UBIFS file-system description object
1847 * @key: node key to lookup
1848 * @node: the node is returned here
1849 * @nm: node name
1850 *
1851 * This function look up and reads a node which contains name hash in the key.
1852 * Since the hash may have collisions, there may be many nodes with the same
1853 * key, so we have to sequentially look to all of them until the needed one is
1854 * found. This function returns zero in case of success, %-ENOENT if the node
1855 * was not found, and a negative error code in case of failure.
1856 */
1857int ubifs_tnc_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1858 void *node, const struct qstr *nm)
1859{
1860 int err, len;
1861 const struct ubifs_dent_node *dent = node;
1862
1863 /*
1864 * We assume that in most of the cases there are no name collisions and
1865 * 'ubifs_tnc_lookup()' returns us the right direntry.
1866 */
1867 err = ubifs_tnc_lookup(c, key, node);
1868 if (err)
1869 return err;
1870
1871 len = le16_to_cpu(dent->nlen);
1872 if (nm->len == len && !memcmp(dent->name, nm->name, len))
1873 return 0;
1874
1875 /*
1876 * Unluckily, there are hash collisions and we have to iterate over
1877 * them look at each direntry with colliding name hash sequentially.
1878 */
1879 return do_lookup_nm(c, key, node, nm);
1880}
1881
1882/**
1883 * correct_parent_keys - correct parent znodes' keys.
1884 * @c: UBIFS file-system description object
1885 * @znode: znode to correct parent znodes for
1886 *
1887 * This is a helper function for 'tnc_insert()'. When the key of the leftmost
1888 * zbranch changes, keys of parent znodes have to be corrected. This helper
1889 * function is called in such situations and corrects the keys if needed.
1890 */
1891static void correct_parent_keys(const struct ubifs_info *c,
1892 struct ubifs_znode *znode)
1893{
1894 union ubifs_key *key, *key1;
1895
1896 ubifs_assert(znode->parent);
1897 ubifs_assert(znode->iip == 0);
1898
1899 key = &znode->zbranch[0].key;
1900 key1 = &znode->parent->zbranch[0].key;
1901
1902 while (keys_cmp(c, key, key1) < 0) {
1903 key_copy(c, key, key1);
1904 znode = znode->parent;
1905 znode->alt = 1;
1906 if (!znode->parent || znode->iip)
1907 break;
1908 key1 = &znode->parent->zbranch[0].key;
1909 }
1910}
1911
1912/**
1913 * insert_zbranch - insert a zbranch into a znode.
1914 * @znode: znode into which to insert
1915 * @zbr: zbranch to insert
1916 * @n: slot number to insert to
1917 *
1918 * This is a helper function for 'tnc_insert()'. UBIFS does not allow "gaps" in
1919 * znode's array of zbranches and keeps zbranches consolidated, so when a new
1920 * zbranch has to be inserted to the @znode->zbranches[]' array at the @n-th
1921 * slot, zbranches starting from @n have to be moved right.
1922 */
1923static void insert_zbranch(struct ubifs_znode *znode,
1924 const struct ubifs_zbranch *zbr, int n)
1925{
1926 int i;
1927
1928 ubifs_assert(ubifs_zn_dirty(znode));
1929
1930 if (znode->level) {
1931 for (i = znode->child_cnt; i > n; i--) {
1932 znode->zbranch[i] = znode->zbranch[i - 1];
1933 if (znode->zbranch[i].znode)
1934 znode->zbranch[i].znode->iip = i;
1935 }
1936 if (zbr->znode)
1937 zbr->znode->iip = n;
1938 } else
1939 for (i = znode->child_cnt; i > n; i--)
1940 znode->zbranch[i] = znode->zbranch[i - 1];
1941
1942 znode->zbranch[n] = *zbr;
1943 znode->child_cnt += 1;
1944
1945 /*
1946 * After inserting at slot zero, the lower bound of the key range of
1947 * this znode may have changed. If this znode is subsequently split
1948 * then the upper bound of the key range may change, and furthermore
1949 * it could change to be lower than the original lower bound. If that
1950 * happens, then it will no longer be possible to find this znode in the
1951 * TNC using the key from the index node on flash. That is bad because
1952 * if it is not found, we will assume it is obsolete and may overwrite
1953 * it. Then if there is an unclean unmount, we will start using the
1954 * old index which will be broken.
1955 *
1956 * So we first mark znodes that have insertions at slot zero, and then
1957 * if they are split we add their lnum/offs to the old_idx tree.
1958 */
1959 if (n == 0)
1960 znode->alt = 1;
1961}
1962
1963/**
1964 * tnc_insert - insert a node into TNC.
1965 * @c: UBIFS file-system description object
1966 * @znode: znode to insert into
1967 * @zbr: branch to insert
1968 * @n: slot number to insert new zbranch to
1969 *
1970 * This function inserts a new node described by @zbr into znode @znode. If
1971 * znode does not have a free slot for new zbranch, it is split. Parent znodes
1972 * are splat as well if needed. Returns zero in case of success or a negative
1973 * error code in case of failure.
1974 */
1975static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode,
1976 struct ubifs_zbranch *zbr, int n)
1977{
1978 struct ubifs_znode *zn, *zi, *zp;
1979 int i, keep, move, appending = 0;
1980 union ubifs_key *key = &zbr->key, *key1;
1981
1982 ubifs_assert(n >= 0 && n <= c->fanout);
1983
1984 /* Implement naive insert for now */
1985again:
1986 zp = znode->parent;
1987 if (znode->child_cnt < c->fanout) {
1988 ubifs_assert(n != c->fanout);
1989 dbg_tnc("inserted at %d level %d, key %s", n, znode->level,
1990 DBGKEY(key));
1991
1992 insert_zbranch(znode, zbr, n);
1993
1994 /* Ensure parent's key is correct */
1995 if (n == 0 && zp && znode->iip == 0)
1996 correct_parent_keys(c, znode);
1997
1998 return 0;
1999 }
2000
2001 /*
2002 * Unfortunately, @znode does not have more empty slots and we have to
2003 * split it.
2004 */
2005 dbg_tnc("splitting level %d, key %s", znode->level, DBGKEY(key));
2006
2007 if (znode->alt)
2008 /*
2009 * We can no longer be sure of finding this znode by key, so we
2010 * record it in the old_idx tree.
2011 */
2012 ins_clr_old_idx_znode(c, znode);
2013
2014 zn = kzalloc(c->max_znode_sz, GFP_NOFS);
2015 if (!zn)
2016 return -ENOMEM;
2017 zn->parent = zp;
2018 zn->level = znode->level;
2019
2020 /* Decide where to split */
2021 if (znode->level == 0 && key_type(c, key) == UBIFS_DATA_KEY) {
2022 /* Try not to split consecutive data keys */
2023 if (n == c->fanout) {
2024 key1 = &znode->zbranch[n - 1].key;
2025 if (key_inum(c, key1) == key_inum(c, key) &&
2026 key_type(c, key1) == UBIFS_DATA_KEY)
2027 appending = 1;
2028 } else
2029 goto check_split;
2030 } else if (appending && n != c->fanout) {
2031 /* Try not to split consecutive data keys */
2032 appending = 0;
2033check_split:
2034 if (n >= (c->fanout + 1) / 2) {
2035 key1 = &znode->zbranch[0].key;
2036 if (key_inum(c, key1) == key_inum(c, key) &&
2037 key_type(c, key1) == UBIFS_DATA_KEY) {
2038 key1 = &znode->zbranch[n].key;
2039 if (key_inum(c, key1) != key_inum(c, key) ||
2040 key_type(c, key1) != UBIFS_DATA_KEY) {
2041 keep = n;
2042 move = c->fanout - keep;
2043 zi = znode;
2044 goto do_split;
2045 }
2046 }
2047 }
2048 }
2049
2050 if (appending) {
2051 keep = c->fanout;
2052 move = 0;
2053 } else {
2054 keep = (c->fanout + 1) / 2;
2055 move = c->fanout - keep;
2056 }
2057
2058 /*
2059 * Although we don't at present, we could look at the neighbors and see
2060 * if we can move some zbranches there.
2061 */
2062
2063 if (n < keep) {
2064 /* Insert into existing znode */
2065 zi = znode;
2066 move += 1;
2067 keep -= 1;
2068 } else {
2069 /* Insert into new znode */
2070 zi = zn;
2071 n -= keep;
2072 /* Re-parent */
2073 if (zn->level != 0)
2074 zbr->znode->parent = zn;
2075 }
2076
2077do_split:
2078
2079 __set_bit(DIRTY_ZNODE, &zn->flags);
2080 atomic_long_inc(&c->dirty_zn_cnt);
2081
2082 zn->child_cnt = move;
2083 znode->child_cnt = keep;
2084
2085 dbg_tnc("moving %d, keeping %d", move, keep);
2086
2087 /* Move zbranch */
2088 for (i = 0; i < move; i++) {
2089 zn->zbranch[i] = znode->zbranch[keep + i];
2090 /* Re-parent */
2091 if (zn->level != 0)
2092 if (zn->zbranch[i].znode) {
2093 zn->zbranch[i].znode->parent = zn;
2094 zn->zbranch[i].znode->iip = i;
2095 }
2096 }
2097
2098 /* Insert new key and branch */
2099 dbg_tnc("inserting at %d level %d, key %s", n, zn->level, DBGKEY(key));
2100
2101 insert_zbranch(zi, zbr, n);
2102
2103 /* Insert new znode (produced by spitting) into the parent */
2104 if (zp) {
2105 if (n == 0 && zi == znode && znode->iip == 0)
2106 correct_parent_keys(c, znode);
2107
2108 /* Locate insertion point */
2109 n = znode->iip + 1;
2110
2111 /* Tail recursion */
2112 zbr->key = zn->zbranch[0].key;
2113 zbr->znode = zn;
2114 zbr->lnum = 0;
2115 zbr->offs = 0;
2116 zbr->len = 0;
2117 znode = zp;
2118
2119 goto again;
2120 }
2121
2122 /* We have to split root znode */
2123 dbg_tnc("creating new zroot at level %d", znode->level + 1);
2124
2125 zi = kzalloc(c->max_znode_sz, GFP_NOFS);
2126 if (!zi)
2127 return -ENOMEM;
2128
2129 zi->child_cnt = 2;
2130 zi->level = znode->level + 1;
2131
2132 __set_bit(DIRTY_ZNODE, &zi->flags);
2133 atomic_long_inc(&c->dirty_zn_cnt);
2134
2135 zi->zbranch[0].key = znode->zbranch[0].key;
2136 zi->zbranch[0].znode = znode;
2137 zi->zbranch[0].lnum = c->zroot.lnum;
2138 zi->zbranch[0].offs = c->zroot.offs;
2139 zi->zbranch[0].len = c->zroot.len;
2140 zi->zbranch[1].key = zn->zbranch[0].key;
2141 zi->zbranch[1].znode = zn;
2142
2143 c->zroot.lnum = 0;
2144 c->zroot.offs = 0;
2145 c->zroot.len = 0;
2146 c->zroot.znode = zi;
2147
2148 zn->parent = zi;
2149 zn->iip = 1;
2150 znode->parent = zi;
2151 znode->iip = 0;
2152
2153 return 0;
2154}
2155
2156/**
2157 * ubifs_tnc_add - add a node to TNC.
2158 * @c: UBIFS file-system description object
2159 * @key: key to add
2160 * @lnum: LEB number of node
2161 * @offs: node offset
2162 * @len: node length
2163 *
2164 * This function adds a node with key @key to TNC. The node may be new or it may
2165 * obsolete some existing one. Returns %0 on success or negative error code on
2166 * failure.
2167 */
2168int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum,
2169 int offs, int len)
2170{
2171 int found, n, err = 0;
2172 struct ubifs_znode *znode;
2173
2174 mutex_lock(&c->tnc_mutex);
2175 dbg_tnc("%d:%d, len %d, key %s", lnum, offs, len, DBGKEY(key));
2176 found = lookup_level0_dirty(c, key, &znode, &n);
2177 if (!found) {
2178 struct ubifs_zbranch zbr;
2179
2180 zbr.znode = NULL;
2181 zbr.lnum = lnum;
2182 zbr.offs = offs;
2183 zbr.len = len;
2184 key_copy(c, key, &zbr.key);
2185 err = tnc_insert(c, znode, &zbr, n + 1);
2186 } else if (found == 1) {
2187 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2188
2189 lnc_free(zbr);
2190 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2191 zbr->lnum = lnum;
2192 zbr->offs = offs;
2193 zbr->len = len;
2194 } else
2195 err = found;
2196 if (!err)
2197 err = dbg_check_tnc(c, 0);
2198 mutex_unlock(&c->tnc_mutex);
2199
2200 return err;
2201}
2202
2203/**
2204 * ubifs_tnc_replace - replace a node in the TNC only if the old node is found.
2205 * @c: UBIFS file-system description object
2206 * @key: key to add
2207 * @old_lnum: LEB number of old node
2208 * @old_offs: old node offset
2209 * @lnum: LEB number of node
2210 * @offs: node offset
2211 * @len: node length
2212 *
2213 * This function replaces a node with key @key in the TNC only if the old node
2214 * is found. This function is called by garbage collection when node are moved.
2215 * Returns %0 on success or negative error code on failure.
2216 */
2217int ubifs_tnc_replace(struct ubifs_info *c, const union ubifs_key *key,
2218 int old_lnum, int old_offs, int lnum, int offs, int len)
2219{
2220 int found, n, err = 0;
2221 struct ubifs_znode *znode;
2222
2223 mutex_lock(&c->tnc_mutex);
2224 dbg_tnc("old LEB %d:%d, new LEB %d:%d, len %d, key %s", old_lnum,
2225 old_offs, lnum, offs, len, DBGKEY(key));
2226 found = lookup_level0_dirty(c, key, &znode, &n);
2227 if (found < 0) {
2228 err = found;
2229 goto out_unlock;
2230 }
2231
2232 if (found == 1) {
2233 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2234
2235 found = 0;
2236 if (zbr->lnum == old_lnum && zbr->offs == old_offs) {
2237 lnc_free(zbr);
2238 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2239 if (err)
2240 goto out_unlock;
2241 zbr->lnum = lnum;
2242 zbr->offs = offs;
2243 zbr->len = len;
2244 found = 1;
2245 } else if (is_hash_key(c, key)) {
2246 found = resolve_collision_directly(c, key, &znode, &n,
2247 old_lnum, old_offs);
2248 dbg_tnc("rc returned %d, znode %p, n %d, LEB %d:%d",
2249 found, znode, n, old_lnum, old_offs);
2250 if (found < 0) {
2251 err = found;
2252 goto out_unlock;
2253 }
2254
2255 if (found) {
2256 /* Ensure the znode is dirtied */
2257 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2258 znode = dirty_cow_bottom_up(c, znode);
2259 if (IS_ERR(znode)) {
2260 err = PTR_ERR(znode);
2261 goto out_unlock;
2262 }
2263 }
2264 zbr = &znode->zbranch[n];
2265 lnc_free(zbr);
2266 err = ubifs_add_dirt(c, zbr->lnum,
2267 zbr->len);
2268 if (err)
2269 goto out_unlock;
2270 zbr->lnum = lnum;
2271 zbr->offs = offs;
2272 zbr->len = len;
2273 }
2274 }
2275 }
2276
2277 if (!found)
2278 err = ubifs_add_dirt(c, lnum, len);
2279
2280 if (!err)
2281 err = dbg_check_tnc(c, 0);
2282
2283out_unlock:
2284 mutex_unlock(&c->tnc_mutex);
2285 return err;
2286}
2287
2288/**
2289 * ubifs_tnc_add_nm - add a "hashed" node to TNC.
2290 * @c: UBIFS file-system description object
2291 * @key: key to add
2292 * @lnum: LEB number of node
2293 * @offs: node offset
2294 * @len: node length
2295 * @nm: node name
2296 *
2297 * This is the same as 'ubifs_tnc_add()' but it should be used with keys which
2298 * may have collisions, like directory entry keys.
2299 */
2300int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
2301 int lnum, int offs, int len, const struct qstr *nm)
2302{
2303 int found, n, err = 0;
2304 struct ubifs_znode *znode;
2305
2306 mutex_lock(&c->tnc_mutex);
2307 dbg_tnc("LEB %d:%d, name '%.*s', key %s", lnum, offs, nm->len, nm->name,
2308 DBGKEY(key));
2309 found = lookup_level0_dirty(c, key, &znode, &n);
2310 if (found < 0) {
2311 err = found;
2312 goto out_unlock;
2313 }
2314
2315 if (found == 1) {
2316 if (c->replaying)
2317 found = fallible_resolve_collision(c, key, &znode, &n,
2318 nm, 1);
2319 else
2320 found = resolve_collision(c, key, &znode, &n, nm);
2321 dbg_tnc("rc returned %d, znode %p, n %d", found, znode, n);
2322 if (found < 0) {
2323 err = found;
2324 goto out_unlock;
2325 }
2326
2327 /* Ensure the znode is dirtied */
2328 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2329 znode = dirty_cow_bottom_up(c, znode);
2330 if (IS_ERR(znode)) {
2331 err = PTR_ERR(znode);
2332 goto out_unlock;
2333 }
2334 }
2335
2336 if (found == 1) {
2337 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2338
2339 lnc_free(zbr);
2340 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2341 zbr->lnum = lnum;
2342 zbr->offs = offs;
2343 zbr->len = len;
2344 goto out_unlock;
2345 }
2346 }
2347
2348 if (!found) {
2349 struct ubifs_zbranch zbr;
2350
2351 zbr.znode = NULL;
2352 zbr.lnum = lnum;
2353 zbr.offs = offs;
2354 zbr.len = len;
2355 key_copy(c, key, &zbr.key);
2356 err = tnc_insert(c, znode, &zbr, n + 1);
2357 if (err)
2358 goto out_unlock;
2359 if (c->replaying) {
2360 /*
2361 * We did not find it in the index so there may be a
2362 * dangling branch still in the index. So we remove it
2363 * by passing 'ubifs_tnc_remove_nm()' the same key but
2364 * an unmatchable name.
2365 */
2366 struct qstr noname = { .len = 0, .name = "" };
2367
2368 err = dbg_check_tnc(c, 0);
2369 mutex_unlock(&c->tnc_mutex);
2370 if (err)
2371 return err;
2372 return ubifs_tnc_remove_nm(c, key, &noname);
2373 }
2374 }
2375
2376out_unlock:
2377 if (!err)
2378 err = dbg_check_tnc(c, 0);
2379 mutex_unlock(&c->tnc_mutex);
2380 return err;
2381}
2382
2383/**
2384 * tnc_delete - delete a znode form TNC.
2385 * @c: UBIFS file-system description object
2386 * @znode: znode to delete from
2387 * @n: zbranch slot number to delete
2388 *
2389 * This function deletes a leaf node from @n-th slot of @znode. Returns zero in
2390 * case of success and a negative error code in case of failure.
2391 */
2392static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n)
2393{
2394 struct ubifs_zbranch *zbr;
2395 struct ubifs_znode *zp;
2396 int i, err;
2397
2398 /* Delete without merge for now */
2399 ubifs_assert(znode->level == 0);
2400 ubifs_assert(n >= 0 && n < c->fanout);
2401 dbg_tnc("deleting %s", DBGKEY(&znode->zbranch[n].key));
2402
2403 zbr = &znode->zbranch[n];
2404 lnc_free(zbr);
2405
2406 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2407 if (err) {
2408 dbg_dump_znode(c, znode);
2409 return err;
2410 }
2411
2412 /* We do not "gap" zbranch slots */
2413 for (i = n; i < znode->child_cnt - 1; i++)
2414 znode->zbranch[i] = znode->zbranch[i + 1];
2415 znode->child_cnt -= 1;
2416
2417 if (znode->child_cnt > 0)
2418 return 0;
2419
2420 /*
2421 * This was the last zbranch, we have to delete this znode from the
2422 * parent.
2423 */
2424
2425 do {
2426 ubifs_assert(!ubifs_zn_obsolete(znode));
2427 ubifs_assert(ubifs_zn_dirty(znode));
2428
2429 zp = znode->parent;
2430 n = znode->iip;
2431
2432 atomic_long_dec(&c->dirty_zn_cnt);
2433
2434 err = insert_old_idx_znode(c, znode);
2435 if (err)
2436 return err;
2437
2438 if (znode->cnext) {
2439 __set_bit(OBSOLETE_ZNODE, &znode->flags);
2440 atomic_long_inc(&c->clean_zn_cnt);
2441 atomic_long_inc(&ubifs_clean_zn_cnt);
2442 } else
2443 kfree(znode);
2444 znode = zp;
2445 } while (znode->child_cnt == 1); /* while removing last child */
2446
2447 /* Remove from znode, entry n - 1 */
2448 znode->child_cnt -= 1;
2449 ubifs_assert(znode->level != 0);
2450 for (i = n; i < znode->child_cnt; i++) {
2451 znode->zbranch[i] = znode->zbranch[i + 1];
2452 if (znode->zbranch[i].znode)
2453 znode->zbranch[i].znode->iip = i;
2454 }
2455
2456 /*
2457 * If this is the root and it has only 1 child then
2458 * collapse the tree.
2459 */
2460 if (!znode->parent) {
2461 while (znode->child_cnt == 1 && znode->level != 0) {
2462 zp = znode;
2463 zbr = &znode->zbranch[0];
2464 znode = get_znode(c, znode, 0);
2465 if (IS_ERR(znode))
2466 return PTR_ERR(znode);
2467 znode = dirty_cow_znode(c, zbr);
2468 if (IS_ERR(znode))
2469 return PTR_ERR(znode);
2470 znode->parent = NULL;
2471 znode->iip = 0;
2472 if (c->zroot.len) {
2473 err = insert_old_idx(c, c->zroot.lnum,
2474 c->zroot.offs);
2475 if (err)
2476 return err;
2477 }
2478 c->zroot.lnum = zbr->lnum;
2479 c->zroot.offs = zbr->offs;
2480 c->zroot.len = zbr->len;
2481 c->zroot.znode = znode;
2482 ubifs_assert(!ubifs_zn_obsolete(zp));
2483 ubifs_assert(ubifs_zn_dirty(zp));
2484 atomic_long_dec(&c->dirty_zn_cnt);
2485
2486 if (zp->cnext) {
2487 __set_bit(OBSOLETE_ZNODE, &zp->flags);
2488 atomic_long_inc(&c->clean_zn_cnt);
2489 atomic_long_inc(&ubifs_clean_zn_cnt);
2490 } else
2491 kfree(zp);
2492 }
2493 }
2494
2495 return 0;
2496}
2497
2498/**
2499 * ubifs_tnc_remove - remove an index entry of a node.
2500 * @c: UBIFS file-system description object
2501 * @key: key of node
2502 *
2503 * Returns %0 on success or negative error code on failure.
2504 */
2505int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key)
2506{
2507 int found, n, err = 0;
2508 struct ubifs_znode *znode;
2509
2510 mutex_lock(&c->tnc_mutex);
2511 dbg_tnc("key %s", DBGKEY(key));
2512 found = lookup_level0_dirty(c, key, &znode, &n);
2513 if (found < 0) {
2514 err = found;
2515 goto out_unlock;
2516 }
2517 if (found == 1)
2518 err = tnc_delete(c, znode, n);
2519 if (!err)
2520 err = dbg_check_tnc(c, 0);
2521
2522out_unlock:
2523 mutex_unlock(&c->tnc_mutex);
2524 return err;
2525}
2526
2527/**
2528 * ubifs_tnc_remove_nm - remove an index entry for a "hashed" node.
2529 * @c: UBIFS file-system description object
2530 * @key: key of node
2531 * @nm: directory entry name
2532 *
2533 * Returns %0 on success or negative error code on failure.
2534 */
2535int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
2536 const struct qstr *nm)
2537{
2538 int n, err;
2539 struct ubifs_znode *znode;
2540
2541 mutex_lock(&c->tnc_mutex);
2542 dbg_tnc("%.*s, key %s", nm->len, nm->name, DBGKEY(key));
2543 err = lookup_level0_dirty(c, key, &znode, &n);
2544 if (err < 0)
2545 goto out_unlock;
2546
2547 if (err) {
2548 if (c->replaying)
2549 err = fallible_resolve_collision(c, key, &znode, &n,
2550 nm, 0);
2551 else
2552 err = resolve_collision(c, key, &znode, &n, nm);
2553 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
2554 if (err < 0)
2555 goto out_unlock;
2556 if (err) {
2557 /* Ensure the znode is dirtied */
2558 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2559 znode = dirty_cow_bottom_up(c, znode);
2560 if (IS_ERR(znode)) {
2561 err = PTR_ERR(znode);
2562 goto out_unlock;
2563 }
2564 }
2565 err = tnc_delete(c, znode, n);
2566 }
2567 }
2568
2569out_unlock:
2570 if (!err)
2571 err = dbg_check_tnc(c, 0);
2572 mutex_unlock(&c->tnc_mutex);
2573 return err;
2574}
2575
2576/**
2577 * key_in_range - determine if a key falls within a range of keys.
2578 * @c: UBIFS file-system description object
2579 * @key: key to check
2580 * @from_key: lowest key in range
2581 * @to_key: highest key in range
2582 *
2583 * This function returns %1 if the key is in range and %0 otherwise.
2584 */
2585static int key_in_range(struct ubifs_info *c, union ubifs_key *key,
2586 union ubifs_key *from_key, union ubifs_key *to_key)
2587{
2588 if (keys_cmp(c, key, from_key) < 0)
2589 return 0;
2590 if (keys_cmp(c, key, to_key) > 0)
2591 return 0;
2592 return 1;
2593}
2594
2595/**
2596 * ubifs_tnc_remove_range - remove index entries in range.
2597 * @c: UBIFS file-system description object
2598 * @from_key: lowest key to remove
2599 * @to_key: highest key to remove
2600 *
2601 * This function removes index entries starting at @from_key and ending at
2602 * @to_key. This function returns zero in case of success and a negative error
2603 * code in case of failure.
2604 */
2605int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key,
2606 union ubifs_key *to_key)
2607{
2608 int i, n, k, err = 0;
2609 struct ubifs_znode *znode;
2610 union ubifs_key *key;
2611
2612 mutex_lock(&c->tnc_mutex);
2613 while (1) {
2614 /* Find first level 0 znode that contains keys to remove */
2615 err = ubifs_lookup_level0(c, from_key, &znode, &n);
2616 if (err < 0)
2617 goto out_unlock;
2618
2619 if (err)
2620 key = from_key;
2621 else {
2622 err = tnc_next(c, &znode, &n);
2623 if (err == -ENOENT) {
2624 err = 0;
2625 goto out_unlock;
2626 }
2627 if (err < 0)
2628 goto out_unlock;
2629 key = &znode->zbranch[n].key;
2630 if (!key_in_range(c, key, from_key, to_key)) {
2631 err = 0;
2632 goto out_unlock;
2633 }
2634 }
2635
2636 /* Ensure the znode is dirtied */
2637 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2638 znode = dirty_cow_bottom_up(c, znode);
2639 if (IS_ERR(znode)) {
2640 err = PTR_ERR(znode);
2641 goto out_unlock;
2642 }
2643 }
2644
2645 /* Remove all keys in range except the first */
2646 for (i = n + 1, k = 0; i < znode->child_cnt; i++, k++) {
2647 key = &znode->zbranch[i].key;
2648 if (!key_in_range(c, key, from_key, to_key))
2649 break;
2650 lnc_free(&znode->zbranch[i]);
2651 err = ubifs_add_dirt(c, znode->zbranch[i].lnum,
2652 znode->zbranch[i].len);
2653 if (err) {
2654 dbg_dump_znode(c, znode);
2655 goto out_unlock;
2656 }
2657 dbg_tnc("removing %s", DBGKEY(key));
2658 }
2659 if (k) {
2660 for (i = n + 1 + k; i < znode->child_cnt; i++)
2661 znode->zbranch[i - k] = znode->zbranch[i];
2662 znode->child_cnt -= k;
2663 }
2664
2665 /* Now delete the first */
2666 err = tnc_delete(c, znode, n);
2667 if (err)
2668 goto out_unlock;
2669 }
2670
2671out_unlock:
2672 if (!err)
2673 err = dbg_check_tnc(c, 0);
2674 mutex_unlock(&c->tnc_mutex);
2675 return err;
2676}
2677
2678/**
2679 * ubifs_tnc_remove_ino - remove an inode from TNC.
2680 * @c: UBIFS file-system description object
2681 * @inum: inode number to remove
2682 *
2683 * This function remove inode @inum and all the extended attributes associated
2684 * with the anode from TNC and returns zero in case of success or a negative
2685 * error code in case of failure.
2686 */
2687int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum)
2688{
2689 union ubifs_key key1, key2;
2690 struct ubifs_dent_node *xent, *pxent = NULL;
2691 struct qstr nm = { .name = NULL };
2692
2693 dbg_tnc("ino %lu", (unsigned long)inum);
2694
2695 /*
2696 * Walk all extended attribute entries and remove them together with
2697 * corresponding extended attribute inodes.
2698 */
2699 lowest_xent_key(c, &key1, inum);
2700 while (1) {
2701 ino_t xattr_inum;
2702 int err;
2703
2704 xent = ubifs_tnc_next_ent(c, &key1, &nm);
2705 if (IS_ERR(xent)) {
2706 err = PTR_ERR(xent);
2707 if (err == -ENOENT)
2708 break;
2709 return err;
2710 }
2711
2712 xattr_inum = le64_to_cpu(xent->inum);
2713 dbg_tnc("xent '%s', ino %lu", xent->name,
2714 (unsigned long)xattr_inum);
2715
2716 nm.name = xent->name;
2717 nm.len = le16_to_cpu(xent->nlen);
2718 err = ubifs_tnc_remove_nm(c, &key1, &nm);
2719 if (err) {
2720 kfree(xent);
2721 return err;
2722 }
2723
2724 lowest_ino_key(c, &key1, xattr_inum);
2725 highest_ino_key(c, &key2, xattr_inum);
2726 err = ubifs_tnc_remove_range(c, &key1, &key2);
2727 if (err) {
2728 kfree(xent);
2729 return err;
2730 }
2731
2732 kfree(pxent);
2733 pxent = xent;
2734 key_read(c, &xent->key, &key1);
2735 }
2736
2737 kfree(pxent);
2738 lowest_ino_key(c, &key1, inum);
2739 highest_ino_key(c, &key2, inum);
2740
2741 return ubifs_tnc_remove_range(c, &key1, &key2);
2742}
2743
2744/**
2745 * ubifs_tnc_next_ent - walk directory or extended attribute entries.
2746 * @c: UBIFS file-system description object
2747 * @key: key of last entry
2748 * @nm: name of last entry found or %NULL
2749 *
2750 * This function finds and reads the next directory or extended attribute entry
2751 * after the given key (@key) if there is one. @nm is used to resolve
2752 * collisions.
2753 *
2754 * If the name of the current entry is not known and only the key is known,
2755 * @nm->name has to be %NULL. In this case the semantics of this function is a
2756 * little bit different and it returns the entry corresponding to this key, not
2757 * the next one. If the key was not found, the closest "right" entry is
2758 * returned.
2759 *
2760 * If the fist entry has to be found, @key has to contain the lowest possible
2761 * key value for this inode and @name has to be %NULL.
2762 *
2763 * This function returns the found directory or extended attribute entry node
2764 * in case of success, %-ENOENT is returned if no entry was found, and a
2765 * negative error code is returned in case of failure.
2766 */
2767struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c,
2768 union ubifs_key *key,
2769 const struct qstr *nm)
2770{
2771 int n, err, type = key_type(c, key);
2772 struct ubifs_znode *znode;
2773 struct ubifs_dent_node *dent;
2774 struct ubifs_zbranch *zbr;
2775 union ubifs_key *dkey;
2776
2777 dbg_tnc("%s %s", nm->name ? (char *)nm->name : "(lowest)", DBGKEY(key));
2778 ubifs_assert(is_hash_key(c, key));
2779
2780 mutex_lock(&c->tnc_mutex);
2781 err = ubifs_lookup_level0(c, key, &znode, &n);
2782 if (unlikely(err < 0))
2783 goto out_unlock;
2784
2785 if (nm->name) {
2786 if (err) {
2787 /* Handle collisions */
2788 err = resolve_collision(c, key, &znode, &n, nm);
2789 dbg_tnc("rc returned %d, znode %p, n %d",
2790 err, znode, n);
2791 if (unlikely(err < 0))
2792 goto out_unlock;
2793 }
2794
2795 /* Now find next entry */
2796 err = tnc_next(c, &znode, &n);
2797 if (unlikely(err))
2798 goto out_unlock;
2799 } else {
2800 /*
2801 * The full name of the entry was not given, in which case the
2802 * behavior of this function is a little different and it
2803 * returns current entry, not the next one.
2804 */
2805 if (!err) {
2806 /*
2807 * However, the given key does not exist in the TNC
2808 * tree and @znode/@n variables contain the closest
2809 * "preceding" element. Switch to the next one.
2810 */
2811 err = tnc_next(c, &znode, &n);
2812 if (err)
2813 goto out_unlock;
2814 }
2815 }
2816
2817 zbr = &znode->zbranch[n];
2818 dent = kmalloc(zbr->len, GFP_NOFS);
2819 if (unlikely(!dent)) {
2820 err = -ENOMEM;
2821 goto out_unlock;
2822 }
2823
2824 /*
2825 * The above 'tnc_next()' call could lead us to the next inode, check
2826 * this.
2827 */
2828 dkey = &zbr->key;
2829 if (key_inum(c, dkey) != key_inum(c, key) ||
2830 key_type(c, dkey) != type) {
2831 err = -ENOENT;
2832 goto out_free;
2833 }
2834
2835 err = tnc_read_node_nm(c, zbr, dent);
2836 if (unlikely(err))
2837 goto out_free;
2838
2839 mutex_unlock(&c->tnc_mutex);
2840 return dent;
2841
2842out_free:
2843 kfree(dent);
2844out_unlock:
2845 mutex_unlock(&c->tnc_mutex);
2846 return ERR_PTR(err);
2847}
2848
2849/**
2850 * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit.
2851 * @c: UBIFS file-system description object
2852 *
2853 * Destroy left-over obsolete znodes from a failed commit.
2854 */
2855static void tnc_destroy_cnext(struct ubifs_info *c)
2856{
2857 struct ubifs_znode *cnext;
2858
2859 if (!c->cnext)
2860 return;
2861 ubifs_assert(c->cmt_state == COMMIT_BROKEN);
2862 cnext = c->cnext;
2863 do {
2864 struct ubifs_znode *znode = cnext;
2865
2866 cnext = cnext->cnext;
2867 if (ubifs_zn_obsolete(znode))
2868 kfree(znode);
2869 } while (cnext && cnext != c->cnext);
2870}
2871
2872/**
2873 * ubifs_tnc_close - close TNC subsystem and free all related resources.
2874 * @c: UBIFS file-system description object
2875 */
2876void ubifs_tnc_close(struct ubifs_info *c)
2877{
2878 tnc_destroy_cnext(c);
2879 if (c->zroot.znode) {
2880 long n;
2881
2882 ubifs_destroy_tnc_subtree(c->zroot.znode);
2883 n = atomic_long_read(&c->clean_zn_cnt);
2884 atomic_long_sub(n, &ubifs_clean_zn_cnt);
2885 }
2886 kfree(c->gap_lebs);
2887 kfree(c->ilebs);
2888 destroy_old_idx(c);
2889}
2890
2891/**
2892 * left_znode - get the znode to the left.
2893 * @c: UBIFS file-system description object
2894 * @znode: znode
2895 *
2896 * This function returns a pointer to the znode to the left of @znode or NULL if
2897 * there is not one. A negative error code is returned on failure.
2898 */
2899static struct ubifs_znode *left_znode(struct ubifs_info *c,
2900 struct ubifs_znode *znode)
2901{
2902 int level = znode->level;
2903
2904 while (1) {
2905 int n = znode->iip - 1;
2906
2907 /* Go up until we can go left */
2908 znode = znode->parent;
2909 if (!znode)
2910 return NULL;
2911 if (n >= 0) {
2912 /* Now go down the rightmost branch to 'level' */
2913 znode = get_znode(c, znode, n);
2914 if (IS_ERR(znode))
2915 return znode;
2916 while (znode->level != level) {
2917 n = znode->child_cnt - 1;
2918 znode = get_znode(c, znode, n);
2919 if (IS_ERR(znode))
2920 return znode;
2921 }
2922 break;
2923 }
2924 }
2925 return znode;
2926}
2927
2928/**
2929 * right_znode - get the znode to the right.
2930 * @c: UBIFS file-system description object
2931 * @znode: znode
2932 *
2933 * This function returns a pointer to the znode to the right of @znode or NULL
2934 * if there is not one. A negative error code is returned on failure.
2935 */
2936static struct ubifs_znode *right_znode(struct ubifs_info *c,
2937 struct ubifs_znode *znode)
2938{
2939 int level = znode->level;
2940
2941 while (1) {
2942 int n = znode->iip + 1;
2943
2944 /* Go up until we can go right */
2945 znode = znode->parent;
2946 if (!znode)
2947 return NULL;
2948 if (n < znode->child_cnt) {
2949 /* Now go down the leftmost branch to 'level' */
2950 znode = get_znode(c, znode, n);
2951 if (IS_ERR(znode))
2952 return znode;
2953 while (znode->level != level) {
2954 znode = get_znode(c, znode, 0);
2955 if (IS_ERR(znode))
2956 return znode;
2957 }
2958 break;
2959 }
2960 }
2961 return znode;
2962}
2963
2964/**
2965 * lookup_znode - find a particular indexing node from TNC.
2966 * @c: UBIFS file-system description object
2967 * @key: index node key to lookup
2968 * @level: index node level
2969 * @lnum: index node LEB number
2970 * @offs: index node offset
2971 *
2972 * This function searches an indexing node by its first key @key and its
2973 * address @lnum:@offs. It looks up the indexing tree by pulling all indexing
2974 * nodes it traverses to TNC. This function is called for indexing nodes which
2975 * were found on the media by scanning, for example when garbage-collecting or
2976 * when doing in-the-gaps commit. This means that the indexing node which is
2977 * looked for does not have to have exactly the same leftmost key @key, because
2978 * the leftmost key may have been changed, in which case TNC will contain a
2979 * dirty znode which still refers the same @lnum:@offs. This function is clever
2980 * enough to recognize such indexing nodes.
2981 *
2982 * Note, if a znode was deleted or changed too much, then this function will
2983 * not find it. For situations like this UBIFS has the old index RB-tree
2984 * (indexed by @lnum:@offs).
2985 *
2986 * This function returns a pointer to the znode found or %NULL if it is not
2987 * found. A negative error code is returned on failure.
2988 */
2989static struct ubifs_znode *lookup_znode(struct ubifs_info *c,
2990 union ubifs_key *key, int level,
2991 int lnum, int offs)
2992{
2993 struct ubifs_znode *znode, *zn;
2994 int n, nn;
2995
2996 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
2997
2998 /*
2999 * The arguments have probably been read off flash, so don't assume
3000 * they are valid.
3001 */
3002 if (level < 0)
3003 return ERR_PTR(-EINVAL);
3004
3005 /* Get the root znode */
3006 znode = c->zroot.znode;
3007 if (!znode) {
3008 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
3009 if (IS_ERR(znode))
3010 return znode;
3011 }
3012 /* Check if it is the one we are looking for */
3013 if (c->zroot.lnum == lnum && c->zroot.offs == offs)
3014 return znode;
3015 /* Descend to the parent level i.e. (level + 1) */
3016 if (level >= znode->level)
3017 return NULL;
3018 while (1) {
3019 ubifs_search_zbranch(c, znode, key, &n);
3020 if (n < 0) {
3021 /*
3022 * We reached a znode where the leftmost key is greater
3023 * than the key we are searching for. This is the same
3024 * situation as the one described in a huge comment at
3025 * the end of the 'ubifs_lookup_level0()' function. And
3026 * for exactly the same reasons we have to try to look
3027 * left before giving up.
3028 */
3029 znode = left_znode(c, znode);
3030 if (!znode)
3031 return NULL;
3032 if (IS_ERR(znode))
3033 return znode;
3034 ubifs_search_zbranch(c, znode, key, &n);
3035 ubifs_assert(n >= 0);
3036 }
3037 if (znode->level == level + 1)
3038 break;
3039 znode = get_znode(c, znode, n);
3040 if (IS_ERR(znode))
3041 return znode;
3042 }
3043 /* Check if the child is the one we are looking for */
3044 if (znode->zbranch[n].lnum == lnum && znode->zbranch[n].offs == offs)
3045 return get_znode(c, znode, n);
3046 /* If the key is unique, there is nowhere else to look */
3047 if (!is_hash_key(c, key))
3048 return NULL;
3049 /*
3050 * The key is not unique and so may be also in the znodes to either
3051 * side.
3052 */
3053 zn = znode;
3054 nn = n;
3055 /* Look left */
3056 while (1) {
3057 /* Move one branch to the left */
3058 if (n)
3059 n -= 1;
3060 else {
3061 znode = left_znode(c, znode);
3062 if (!znode)
3063 break;
3064 if (IS_ERR(znode))
3065 return znode;
3066 n = znode->child_cnt - 1;
3067 }
3068 /* Check it */
3069 if (znode->zbranch[n].lnum == lnum &&
3070 znode->zbranch[n].offs == offs)
3071 return get_znode(c, znode, n);
3072 /* Stop if the key is less than the one we are looking for */
3073 if (keys_cmp(c, &znode->zbranch[n].key, key) < 0)
3074 break;
3075 }
3076 /* Back to the middle */
3077 znode = zn;
3078 n = nn;
3079 /* Look right */
3080 while (1) {
3081 /* Move one branch to the right */
3082 if (++n >= znode->child_cnt) {
3083 znode = right_znode(c, znode);
3084 if (!znode)
3085 break;
3086 if (IS_ERR(znode))
3087 return znode;
3088 n = 0;
3089 }
3090 /* Check it */
3091 if (znode->zbranch[n].lnum == lnum &&
3092 znode->zbranch[n].offs == offs)
3093 return get_znode(c, znode, n);
3094 /* Stop if the key is greater than the one we are looking for */
3095 if (keys_cmp(c, &znode->zbranch[n].key, key) > 0)
3096 break;
3097 }
3098 return NULL;
3099}
3100
3101/**
3102 * is_idx_node_in_tnc - determine if an index node is in the TNC.
3103 * @c: UBIFS file-system description object
3104 * @key: key of index node
3105 * @level: index node level
3106 * @lnum: LEB number of index node
3107 * @offs: offset of index node
3108 *
3109 * This function returns %0 if the index node is not referred to in the TNC, %1
3110 * if the index node is referred to in the TNC and the corresponding znode is
3111 * dirty, %2 if an index node is referred to in the TNC and the corresponding
3112 * znode is clean, and a negative error code in case of failure.
3113 *
3114 * Note, the @key argument has to be the key of the first child. Also note,
3115 * this function relies on the fact that 0:0 is never a valid LEB number and
3116 * offset for a main-area node.
3117 */
3118int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level,
3119 int lnum, int offs)
3120{
3121 struct ubifs_znode *znode;
3122
3123 znode = lookup_znode(c, key, level, lnum, offs);
3124 if (!znode)
3125 return 0;
3126 if (IS_ERR(znode))
3127 return PTR_ERR(znode);
3128
3129 return ubifs_zn_dirty(znode) ? 1 : 2;
3130}
3131
3132/**
3133 * is_leaf_node_in_tnc - determine if a non-indexing not is in the TNC.
3134 * @c: UBIFS file-system description object
3135 * @key: node key
3136 * @lnum: node LEB number
3137 * @offs: node offset
3138 *
3139 * This function returns %1 if the node is referred to in the TNC, %0 if it is
3140 * not, and a negative error code in case of failure.
3141 *
3142 * Note, this function relies on the fact that 0:0 is never a valid LEB number
3143 * and offset for a main-area node.
3144 */
3145static int is_leaf_node_in_tnc(struct ubifs_info *c, union ubifs_key *key,
3146 int lnum, int offs)
3147{
3148 struct ubifs_zbranch *zbr;
3149 struct ubifs_znode *znode, *zn;
3150 int n, found, err, nn;
3151 const int unique = !is_hash_key(c, key);
3152
3153 found = ubifs_lookup_level0(c, key, &znode, &n);
3154 if (found < 0)
3155 return found; /* Error code */
3156 if (!found)
3157 return 0;
3158 zbr = &znode->zbranch[n];
3159 if (lnum == zbr->lnum && offs == zbr->offs)
3160 return 1; /* Found it */
3161 if (unique)
3162 return 0;
3163 /*
3164 * Because the key is not unique, we have to look left
3165 * and right as well
3166 */
3167 zn = znode;
3168 nn = n;
3169 /* Look left */
3170 while (1) {
3171 err = tnc_prev(c, &znode, &n);
3172 if (err == -ENOENT)
3173 break;
3174 if (err)
3175 return err;
3176 if (keys_cmp(c, key, &znode->zbranch[n].key))
3177 break;
3178 zbr = &znode->zbranch[n];
3179 if (lnum == zbr->lnum && offs == zbr->offs)
3180 return 1; /* Found it */
3181 }
3182 /* Look right */
3183 znode = zn;
3184 n = nn;
3185 while (1) {
3186 err = tnc_next(c, &znode, &n);
3187 if (err) {
3188 if (err == -ENOENT)
3189 return 0;
3190 return err;
3191 }
3192 if (keys_cmp(c, key, &znode->zbranch[n].key))
3193 break;
3194 zbr = &znode->zbranch[n];
3195 if (lnum == zbr->lnum && offs == zbr->offs)
3196 return 1; /* Found it */
3197 }
3198 return 0;
3199}
3200
3201/**
3202 * ubifs_tnc_has_node - determine whether a node is in the TNC.
3203 * @c: UBIFS file-system description object
3204 * @key: node key
3205 * @level: index node level (if it is an index node)
3206 * @lnum: node LEB number
3207 * @offs: node offset
3208 * @is_idx: non-zero if the node is an index node
3209 *
3210 * This function returns %1 if the node is in the TNC, %0 if it is not, and a
3211 * negative error code in case of failure. For index nodes, @key has to be the
3212 * key of the first child. An index node is considered to be in the TNC only if
3213 * the corresponding znode is clean or has not been loaded.
3214 */
3215int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level,
3216 int lnum, int offs, int is_idx)
3217{
3218 int err;
3219
3220 mutex_lock(&c->tnc_mutex);
3221 if (is_idx) {
3222 err = is_idx_node_in_tnc(c, key, level, lnum, offs);
3223 if (err < 0)
3224 goto out_unlock;
3225 if (err == 1)
3226 /* The index node was found but it was dirty */
3227 err = 0;
3228 else if (err == 2)
3229 /* The index node was found and it was clean */
3230 err = 1;
3231 else
3232 BUG_ON(err != 0);
3233 } else
3234 err = is_leaf_node_in_tnc(c, key, lnum, offs);
3235
3236out_unlock:
3237 mutex_unlock(&c->tnc_mutex);
3238 return err;
3239}
3240
3241/**
3242 * ubifs_dirty_idx_node - dirty an index node.
3243 * @c: UBIFS file-system description object
3244 * @key: index node key
3245 * @level: index node level
3246 * @lnum: index node LEB number
3247 * @offs: index node offset
3248 *
3249 * This function loads and dirties an index node so that it can be garbage
3250 * collected. The @key argument has to be the key of the first child. This
3251 * function relies on the fact that 0:0 is never a valid LEB number and offset
3252 * for a main-area node. Returns %0 on success and a negative error code on
3253 * failure.
3254 */
3255int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level,
3256 int lnum, int offs)
3257{
3258 struct ubifs_znode *znode;
3259 int err = 0;
3260
3261 mutex_lock(&c->tnc_mutex);
3262 znode = lookup_znode(c, key, level, lnum, offs);
3263 if (!znode)
3264 goto out_unlock;
3265 if (IS_ERR(znode)) {
3266 err = PTR_ERR(znode);
3267 goto out_unlock;
3268 }
3269 znode = dirty_cow_bottom_up(c, znode);
3270 if (IS_ERR(znode)) {
3271 err = PTR_ERR(znode);
3272 goto out_unlock;
3273 }
3274
3275out_unlock:
3276 mutex_unlock(&c->tnc_mutex);
3277 return err;
3278}
3279
3280#ifdef CONFIG_UBIFS_FS_DEBUG
3281
3282/**
3283 * dbg_check_inode_size - check if inode size is correct.
3284 * @c: UBIFS file-system description object
3285 * @inum: inode number
3286 * @size: inode size
3287 *
3288 * This function makes sure that the inode size (@size) is correct and it does
3289 * not have any pages beyond @size. Returns zero if the inode is OK, %-EINVAL
3290 * if it has a data page beyond @size, and other negative error code in case of
3291 * other errors.
3292 */
3293int dbg_check_inode_size(struct ubifs_info *c, const struct inode *inode,
3294 loff_t size)
3295{
3296 int err, n;
3297 union ubifs_key from_key, to_key, *key;
3298 struct ubifs_znode *znode;
3299 unsigned int block;
3300
3301 if (!S_ISREG(inode->i_mode))
3302 return 0;
3303 if (!dbg_is_chk_gen(c))
3304 return 0;
3305
3306 block = (size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT;
3307 data_key_init(c, &from_key, inode->i_ino, block);
3308 highest_data_key(c, &to_key, inode->i_ino);
3309
3310 mutex_lock(&c->tnc_mutex);
3311 err = ubifs_lookup_level0(c, &from_key, &znode, &n);
3312 if (err < 0)
3313 goto out_unlock;
3314
3315 if (err) {
3316 err = -EINVAL;
3317 key = &from_key;
3318 goto out_dump;
3319 }
3320
3321 err = tnc_next(c, &znode, &n);
3322 if (err == -ENOENT) {
3323 err = 0;
3324 goto out_unlock;
3325 }
3326 if (err < 0)
3327 goto out_unlock;
3328
3329 ubifs_assert(err == 0);
3330 key = &znode->zbranch[n].key;
3331 if (!key_in_range(c, key, &from_key, &to_key))
3332 goto out_unlock;
3333
3334out_dump:
3335 block = key_block(c, key);
3336 ubifs_err("inode %lu has size %lld, but there are data at offset %lld "
3337 "(data key %s)", (unsigned long)inode->i_ino, size,
3338 ((loff_t)block) << UBIFS_BLOCK_SHIFT, DBGKEY(key));
3339 mutex_unlock(&c->tnc_mutex);
3340 dbg_dump_inode(c, inode);
3341 dbg_dump_stack();
3342 return -EINVAL;
3343
3344out_unlock:
3345 mutex_unlock(&c->tnc_mutex);
3346 return err;
3347}
3348
3349#endif /* CONFIG_UBIFS_FS_DEBUG */
1/*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * Authors: Adrian Hunter
20 * Artem Bityutskiy (Битюцкий Артём)
21 */
22
23/*
24 * This file implements TNC (Tree Node Cache) which caches indexing nodes of
25 * the UBIFS B-tree.
26 *
27 * At the moment the locking rules of the TNC tree are quite simple and
28 * straightforward. We just have a mutex and lock it when we traverse the
29 * tree. If a znode is not in memory, we read it from flash while still having
30 * the mutex locked.
31 */
32
33#include <linux/crc32.h>
34#include <linux/slab.h>
35#include "ubifs.h"
36
37/*
38 * Returned codes of 'matches_name()' and 'fallible_matches_name()' functions.
39 * @NAME_LESS: name corresponding to the first argument is less than second
40 * @NAME_MATCHES: names match
41 * @NAME_GREATER: name corresponding to the second argument is greater than
42 * first
43 * @NOT_ON_MEDIA: node referred by zbranch does not exist on the media
44 *
45 * These constants were introduce to improve readability.
46 */
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 {
101 ubifs_err("old idx added twice!");
102 kfree(old_idx);
103 return 0;
104 }
105 }
106 rb_link_node(&old_idx->rb, parent, p);
107 rb_insert_color(&old_idx->rb, &c->old_idx);
108 return 0;
109}
110
111/**
112 * insert_old_idx_znode - record a znode obsoleted since last commit start.
113 * @c: UBIFS file-system description object
114 * @znode: znode of obsoleted index node
115 *
116 * Returns %0 on success, and a negative error code on failure.
117 */
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{
181 struct ubifs_old_idx *old_idx, *n;
182
183 rbtree_postorder_for_each_entry_safe(old_idx, n, &c->old_idx, rb)
184 kfree(old_idx);
185
186 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
201 zn = kmalloc(c->max_znode_sz, GFP_NOFS);
202 if (unlikely(!zn))
203 return ERR_PTR(-ENOMEM);
204
205 memcpy(zn, znode, c->max_znode_sz);
206 zn->cnext = NULL;
207 __set_bit(DIRTY_ZNODE, &zn->flags);
208 __clear_bit(COW_ZNODE, &zn->flags);
209
210 ubifs_assert(!ubifs_zn_obsolete(znode));
211 __set_bit(OBSOLETE_ZNODE, &znode->flags);
212
213 if (znode->level != 0) {
214 int i;
215 const int n = zn->child_cnt;
216
217 /* The children now have new parent */
218 for (i = 0; i < n; i++) {
219 struct ubifs_zbranch *zbr = &zn->zbranch[i];
220
221 if (zbr->znode)
222 zbr->znode->parent = zn;
223 }
224 }
225
226 atomic_long_inc(&c->dirty_zn_cnt);
227 return zn;
228}
229
230/**
231 * add_idx_dirt - add dirt due to a dirty znode.
232 * @c: UBIFS file-system description object
233 * @lnum: LEB number of index node
234 * @dirt: size of index node
235 *
236 * This function updates lprops dirty space and the new size of the index.
237 */
238static int add_idx_dirt(struct ubifs_info *c, int lnum, int dirt)
239{
240 c->calc_idx_sz -= ALIGN(dirt, 8);
241 return ubifs_add_dirt(c, lnum, dirt);
242}
243
244/**
245 * dirty_cow_znode - ensure a znode is not being committed.
246 * @c: UBIFS file-system description object
247 * @zbr: branch of znode to check
248 *
249 * Returns dirtied znode on success or negative error code on failure.
250 */
251static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c,
252 struct ubifs_zbranch *zbr)
253{
254 struct ubifs_znode *znode = zbr->znode;
255 struct ubifs_znode *zn;
256 int err;
257
258 if (!ubifs_zn_cow(znode)) {
259 /* znode is not being committed */
260 if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) {
261 atomic_long_inc(&c->dirty_zn_cnt);
262 atomic_long_dec(&c->clean_zn_cnt);
263 atomic_long_dec(&ubifs_clean_zn_cnt);
264 err = add_idx_dirt(c, zbr->lnum, zbr->len);
265 if (unlikely(err))
266 return ERR_PTR(err);
267 }
268 return znode;
269 }
270
271 zn = copy_znode(c, znode);
272 if (IS_ERR(zn))
273 return zn;
274
275 if (zbr->len) {
276 err = insert_old_idx(c, zbr->lnum, zbr->offs);
277 if (unlikely(err))
278 return ERR_PTR(err);
279 err = add_idx_dirt(c, zbr->lnum, zbr->len);
280 } else
281 err = 0;
282
283 zbr->znode = zn;
284 zbr->lnum = 0;
285 zbr->offs = 0;
286 zbr->len = 0;
287
288 if (unlikely(err))
289 return ERR_PTR(err);
290 return zn;
291}
292
293/**
294 * lnc_add - add a leaf node to the leaf node cache.
295 * @c: UBIFS file-system description object
296 * @zbr: zbranch of leaf node
297 * @node: leaf node
298 *
299 * Leaf nodes are non-index nodes directory entry nodes or data nodes. The
300 * purpose of the leaf node cache is to save re-reading the same leaf node over
301 * and over again. Most things are cached by VFS, however the file system must
302 * cache directory entries for readdir and for resolving hash collisions. The
303 * present implementation of the leaf node cache is extremely simple, and
304 * allows for error returns that are not used but that may be needed if a more
305 * complex implementation is created.
306 *
307 * Note, this function does not add the @node object to LNC directly, but
308 * allocates a copy of the object and adds the copy to LNC. The reason for this
309 * is that @node has been allocated outside of the TNC subsystem and will be
310 * used with @c->tnc_mutex unlock upon return from the TNC subsystem. But LNC
311 * may be changed at any time, e.g. freed by the shrinker.
312 */
313static int lnc_add(struct ubifs_info *c, struct ubifs_zbranch *zbr,
314 const void *node)
315{
316 int err;
317 void *lnc_node;
318 const struct ubifs_dent_node *dent = node;
319
320 ubifs_assert(!zbr->leaf);
321 ubifs_assert(zbr->len != 0);
322 ubifs_assert(is_hash_key(c, &zbr->key));
323
324 err = ubifs_validate_entry(c, dent);
325 if (err) {
326 dump_stack();
327 ubifs_dump_node(c, dent);
328 return err;
329 }
330
331 lnc_node = kmemdup(node, zbr->len, GFP_NOFS);
332 if (!lnc_node)
333 /* We don't have to have the cache, so no error */
334 return 0;
335
336 zbr->leaf = lnc_node;
337 return 0;
338}
339
340 /**
341 * lnc_add_directly - add a leaf node to the leaf-node-cache.
342 * @c: UBIFS file-system description object
343 * @zbr: zbranch of leaf node
344 * @node: leaf node
345 *
346 * This function is similar to 'lnc_add()', but it does not create a copy of
347 * @node but inserts @node to TNC directly.
348 */
349static int lnc_add_directly(struct ubifs_info *c, struct ubifs_zbranch *zbr,
350 void *node)
351{
352 int err;
353
354 ubifs_assert(!zbr->leaf);
355 ubifs_assert(zbr->len != 0);
356
357 err = ubifs_validate_entry(c, node);
358 if (err) {
359 dump_stack();
360 ubifs_dump_node(c, node);
361 return err;
362 }
363
364 zbr->leaf = node;
365 return 0;
366}
367
368/**
369 * lnc_free - remove a leaf node from the leaf node cache.
370 * @zbr: zbranch of leaf node
371 * @node: leaf node
372 */
373static void lnc_free(struct ubifs_zbranch *zbr)
374{
375 if (!zbr->leaf)
376 return;
377 kfree(zbr->leaf);
378 zbr->leaf = NULL;
379}
380
381/**
382 * tnc_read_node_nm - read a "hashed" leaf node.
383 * @c: UBIFS file-system description object
384 * @zbr: key and position of the node
385 * @node: node is returned here
386 *
387 * This function reads a "hashed" node defined by @zbr from the leaf node cache
388 * (in it is there) or from the hash media, in which case the node is also
389 * added to LNC. Returns zero in case of success or a negative negative error
390 * code in case of failure.
391 */
392static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr,
393 void *node)
394{
395 int err;
396
397 ubifs_assert(is_hash_key(c, &zbr->key));
398
399 if (zbr->leaf) {
400 /* Read from the leaf node cache */
401 ubifs_assert(zbr->len != 0);
402 memcpy(node, zbr->leaf, zbr->len);
403 return 0;
404 }
405
406 err = ubifs_tnc_read_node(c, zbr, node);
407 if (err)
408 return err;
409
410 /* Add the node to the leaf node cache */
411 err = lnc_add(c, zbr, node);
412 return err;
413}
414
415/**
416 * try_read_node - read a node if it is a node.
417 * @c: UBIFS file-system description object
418 * @buf: buffer to read to
419 * @type: node type
420 * @len: node length (not aligned)
421 * @lnum: LEB number of node to read
422 * @offs: offset of node to read
423 *
424 * This function tries to read a node of known type and length, checks it and
425 * stores it in @buf. This function returns %1 if a node is present and %0 if
426 * a node is not present. A negative error code is returned for I/O errors.
427 * This function performs that same function as ubifs_read_node except that
428 * it does not require that there is actually a node present and instead
429 * the return code indicates if a node was read.
430 *
431 * Note, this function does not check CRC of data nodes if @c->no_chk_data_crc
432 * is true (it is controlled by corresponding mount option). However, if
433 * @c->mounting or @c->remounting_rw is true (we are mounting or re-mounting to
434 * R/W mode), @c->no_chk_data_crc is ignored and CRC is checked. This is
435 * because during mounting or re-mounting from R/O mode to R/W mode we may read
436 * journal nodes (when replying the journal or doing the recovery) and the
437 * journal nodes may potentially be corrupted, so checking is required.
438 */
439static int try_read_node(const struct ubifs_info *c, void *buf, int type,
440 int len, int lnum, int offs)
441{
442 int err, node_len;
443 struct ubifs_ch *ch = buf;
444 uint32_t crc, node_crc;
445
446 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
447
448 err = ubifs_leb_read(c, lnum, buf, offs, len, 1);
449 if (err) {
450 ubifs_err("cannot read node type %d from LEB %d:%d, error %d",
451 type, lnum, offs, err);
452 return err;
453 }
454
455 if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC)
456 return 0;
457
458 if (ch->node_type != type)
459 return 0;
460
461 node_len = le32_to_cpu(ch->len);
462 if (node_len != len)
463 return 0;
464
465 if (type == UBIFS_DATA_NODE && c->no_chk_data_crc && !c->mounting &&
466 !c->remounting_rw)
467 return 1;
468
469 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
470 node_crc = le32_to_cpu(ch->crc);
471 if (crc != node_crc)
472 return 0;
473
474 return 1;
475}
476
477/**
478 * fallible_read_node - try to read a leaf node.
479 * @c: UBIFS file-system description object
480 * @key: key of node to read
481 * @zbr: position of node
482 * @node: node returned
483 *
484 * This function tries to read a node and returns %1 if the node is read, %0
485 * if the node is not present, and a negative error code in the case of error.
486 */
487static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
488 struct ubifs_zbranch *zbr, void *node)
489{
490 int ret;
491
492 dbg_tnck(key, "LEB %d:%d, key ", zbr->lnum, zbr->offs);
493
494 ret = try_read_node(c, node, key_type(c, key), zbr->len, zbr->lnum,
495 zbr->offs);
496 if (ret == 1) {
497 union ubifs_key node_key;
498 struct ubifs_dent_node *dent = node;
499
500 /* All nodes have key in the same place */
501 key_read(c, &dent->key, &node_key);
502 if (keys_cmp(c, key, &node_key) != 0)
503 ret = 0;
504 }
505 if (ret == 0 && c->replaying)
506 dbg_mntk(key, "dangling branch LEB %d:%d len %d, key ",
507 zbr->lnum, zbr->offs, zbr->len);
508 return ret;
509}
510
511/**
512 * matches_name - determine if a direntry or xattr entry matches a given name.
513 * @c: UBIFS file-system description object
514 * @zbr: zbranch of dent
515 * @nm: name to match
516 *
517 * This function checks if xentry/direntry referred by zbranch @zbr matches name
518 * @nm. Returns %NAME_MATCHES if it does, %NAME_LESS if the name referred by
519 * @zbr is less than @nm, and %NAME_GREATER if it is greater than @nm. In case
520 * of failure, a negative error code is returned.
521 */
522static int matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr,
523 const struct qstr *nm)
524{
525 struct ubifs_dent_node *dent;
526 int nlen, err;
527
528 /* If possible, match against the dent in the leaf node cache */
529 if (!zbr->leaf) {
530 dent = kmalloc(zbr->len, GFP_NOFS);
531 if (!dent)
532 return -ENOMEM;
533
534 err = ubifs_tnc_read_node(c, zbr, dent);
535 if (err)
536 goto out_free;
537
538 /* Add the node to the leaf node cache */
539 err = lnc_add_directly(c, zbr, dent);
540 if (err)
541 goto out_free;
542 } else
543 dent = zbr->leaf;
544
545 nlen = le16_to_cpu(dent->nlen);
546 err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
547 if (err == 0) {
548 if (nlen == nm->len)
549 return NAME_MATCHES;
550 else if (nlen < nm->len)
551 return NAME_LESS;
552 else
553 return NAME_GREATER;
554 } else if (err < 0)
555 return NAME_LESS;
556 else
557 return NAME_GREATER;
558
559out_free:
560 kfree(dent);
561 return err;
562}
563
564/**
565 * get_znode - get a TNC znode that may not be loaded yet.
566 * @c: UBIFS file-system description object
567 * @znode: parent znode
568 * @n: znode branch slot number
569 *
570 * This function returns the znode or a negative error code.
571 */
572static struct ubifs_znode *get_znode(struct ubifs_info *c,
573 struct ubifs_znode *znode, int n)
574{
575 struct ubifs_zbranch *zbr;
576
577 zbr = &znode->zbranch[n];
578 if (zbr->znode)
579 znode = zbr->znode;
580 else
581 znode = ubifs_load_znode(c, zbr, znode, n);
582 return znode;
583}
584
585/**
586 * tnc_next - find next TNC entry.
587 * @c: UBIFS file-system description object
588 * @zn: znode is passed and returned here
589 * @n: znode branch slot number is passed and returned here
590 *
591 * This function returns %0 if the next TNC entry is found, %-ENOENT if there is
592 * no next entry, or a negative error code otherwise.
593 */
594static int tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
595{
596 struct ubifs_znode *znode = *zn;
597 int nn = *n;
598
599 nn += 1;
600 if (nn < znode->child_cnt) {
601 *n = nn;
602 return 0;
603 }
604 while (1) {
605 struct ubifs_znode *zp;
606
607 zp = znode->parent;
608 if (!zp)
609 return -ENOENT;
610 nn = znode->iip + 1;
611 znode = zp;
612 if (nn < znode->child_cnt) {
613 znode = get_znode(c, znode, nn);
614 if (IS_ERR(znode))
615 return PTR_ERR(znode);
616 while (znode->level != 0) {
617 znode = get_znode(c, znode, 0);
618 if (IS_ERR(znode))
619 return PTR_ERR(znode);
620 }
621 nn = 0;
622 break;
623 }
624 }
625 *zn = znode;
626 *n = nn;
627 return 0;
628}
629
630/**
631 * tnc_prev - find previous TNC entry.
632 * @c: UBIFS file-system description object
633 * @zn: znode is returned here
634 * @n: znode branch slot number is passed and returned here
635 *
636 * This function returns %0 if the previous TNC entry is found, %-ENOENT if
637 * there is no next entry, or a negative error code otherwise.
638 */
639static int tnc_prev(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
640{
641 struct ubifs_znode *znode = *zn;
642 int nn = *n;
643
644 if (nn > 0) {
645 *n = nn - 1;
646 return 0;
647 }
648 while (1) {
649 struct ubifs_znode *zp;
650
651 zp = znode->parent;
652 if (!zp)
653 return -ENOENT;
654 nn = znode->iip - 1;
655 znode = zp;
656 if (nn >= 0) {
657 znode = get_znode(c, znode, nn);
658 if (IS_ERR(znode))
659 return PTR_ERR(znode);
660 while (znode->level != 0) {
661 nn = znode->child_cnt - 1;
662 znode = get_znode(c, znode, nn);
663 if (IS_ERR(znode))
664 return PTR_ERR(znode);
665 }
666 nn = znode->child_cnt - 1;
667 break;
668 }
669 }
670 *zn = znode;
671 *n = nn;
672 return 0;
673}
674
675/**
676 * resolve_collision - resolve a collision.
677 * @c: UBIFS file-system description object
678 * @key: key of a directory or extended attribute entry
679 * @zn: znode is returned here
680 * @n: zbranch number is passed and returned here
681 * @nm: name of the entry
682 *
683 * This function is called for "hashed" keys to make sure that the found key
684 * really corresponds to the looked up node (directory or extended attribute
685 * entry). It returns %1 and sets @zn and @n if the collision is resolved.
686 * %0 is returned if @nm is not found and @zn and @n are set to the previous
687 * entry, i.e. to the entry after which @nm could follow if it were in TNC.
688 * This means that @n may be set to %-1 if the leftmost key in @zn is the
689 * previous one. A negative error code is returned on failures.
690 */
691static int resolve_collision(struct ubifs_info *c, const union ubifs_key *key,
692 struct ubifs_znode **zn, int *n,
693 const struct qstr *nm)
694{
695 int err;
696
697 err = matches_name(c, &(*zn)->zbranch[*n], nm);
698 if (unlikely(err < 0))
699 return err;
700 if (err == NAME_MATCHES)
701 return 1;
702
703 if (err == NAME_GREATER) {
704 /* Look left */
705 while (1) {
706 err = tnc_prev(c, zn, n);
707 if (err == -ENOENT) {
708 ubifs_assert(*n == 0);
709 *n = -1;
710 return 0;
711 }
712 if (err < 0)
713 return err;
714 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
715 /*
716 * We have found the branch after which we would
717 * like to insert, but inserting in this znode
718 * may still be wrong. Consider the following 3
719 * znodes, in the case where we are resolving a
720 * collision with Key2.
721 *
722 * znode zp
723 * ----------------------
724 * level 1 | Key0 | Key1 |
725 * -----------------------
726 * | |
727 * znode za | | znode zb
728 * ------------ ------------
729 * level 0 | Key0 | | Key2 |
730 * ------------ ------------
731 *
732 * The lookup finds Key2 in znode zb. Lets say
733 * there is no match and the name is greater so
734 * we look left. When we find Key0, we end up
735 * here. If we return now, we will insert into
736 * znode za at slot n = 1. But that is invalid
737 * according to the parent's keys. Key2 must
738 * be inserted into znode zb.
739 *
740 * Note, this problem is not relevant for the
741 * case when we go right, because
742 * 'tnc_insert()' would correct the parent key.
743 */
744 if (*n == (*zn)->child_cnt - 1) {
745 err = tnc_next(c, zn, n);
746 if (err) {
747 /* Should be impossible */
748 ubifs_assert(0);
749 if (err == -ENOENT)
750 err = -EINVAL;
751 return err;
752 }
753 ubifs_assert(*n == 0);
754 *n = -1;
755 }
756 return 0;
757 }
758 err = matches_name(c, &(*zn)->zbranch[*n], nm);
759 if (err < 0)
760 return err;
761 if (err == NAME_LESS)
762 return 0;
763 if (err == NAME_MATCHES)
764 return 1;
765 ubifs_assert(err == NAME_GREATER);
766 }
767 } else {
768 int nn = *n;
769 struct ubifs_znode *znode = *zn;
770
771 /* Look right */
772 while (1) {
773 err = tnc_next(c, &znode, &nn);
774 if (err == -ENOENT)
775 return 0;
776 if (err < 0)
777 return err;
778 if (keys_cmp(c, &znode->zbranch[nn].key, key))
779 return 0;
780 err = matches_name(c, &znode->zbranch[nn], nm);
781 if (err < 0)
782 return err;
783 if (err == NAME_GREATER)
784 return 0;
785 *zn = znode;
786 *n = nn;
787 if (err == NAME_MATCHES)
788 return 1;
789 ubifs_assert(err == NAME_LESS);
790 }
791 }
792}
793
794/**
795 * fallible_matches_name - determine if a dent matches a given name.
796 * @c: UBIFS file-system description object
797 * @zbr: zbranch of dent
798 * @nm: name to match
799 *
800 * This is a "fallible" version of 'matches_name()' function which does not
801 * panic if the direntry/xentry referred by @zbr does not exist on the media.
802 *
803 * This function checks if xentry/direntry referred by zbranch @zbr matches name
804 * @nm. Returns %NAME_MATCHES it does, %NAME_LESS if the name referred by @zbr
805 * is less than @nm, %NAME_GREATER if it is greater than @nm, and @NOT_ON_MEDIA
806 * if xentry/direntry referred by @zbr does not exist on the media. A negative
807 * error code is returned in case of failure.
808 */
809static int fallible_matches_name(struct ubifs_info *c,
810 struct ubifs_zbranch *zbr,
811 const struct qstr *nm)
812{
813 struct ubifs_dent_node *dent;
814 int nlen, err;
815
816 /* If possible, match against the dent in the leaf node cache */
817 if (!zbr->leaf) {
818 dent = kmalloc(zbr->len, GFP_NOFS);
819 if (!dent)
820 return -ENOMEM;
821
822 err = fallible_read_node(c, &zbr->key, zbr, dent);
823 if (err < 0)
824 goto out_free;
825 if (err == 0) {
826 /* The node was not present */
827 err = NOT_ON_MEDIA;
828 goto out_free;
829 }
830 ubifs_assert(err == 1);
831
832 err = lnc_add_directly(c, zbr, dent);
833 if (err)
834 goto out_free;
835 } else
836 dent = zbr->leaf;
837
838 nlen = le16_to_cpu(dent->nlen);
839 err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
840 if (err == 0) {
841 if (nlen == nm->len)
842 return NAME_MATCHES;
843 else if (nlen < nm->len)
844 return NAME_LESS;
845 else
846 return NAME_GREATER;
847 } else if (err < 0)
848 return NAME_LESS;
849 else
850 return NAME_GREATER;
851
852out_free:
853 kfree(dent);
854 return err;
855}
856
857/**
858 * fallible_resolve_collision - resolve a collision even if nodes are missing.
859 * @c: UBIFS file-system description object
860 * @key: key
861 * @zn: znode is returned here
862 * @n: branch number is passed and returned here
863 * @nm: name of directory entry
864 * @adding: indicates caller is adding a key to the TNC
865 *
866 * This is a "fallible" version of the 'resolve_collision()' function which
867 * does not panic if one of the nodes referred to by TNC does not exist on the
868 * media. This may happen when replaying the journal if a deleted node was
869 * Garbage-collected and the commit was not done. A branch that refers to a node
870 * that is not present is called a dangling branch. The following are the return
871 * codes for this function:
872 * o if @nm was found, %1 is returned and @zn and @n are set to the found
873 * branch;
874 * o if we are @adding and @nm was not found, %0 is returned;
875 * o if we are not @adding and @nm was not found, but a dangling branch was
876 * found, then %1 is returned and @zn and @n are set to the dangling branch;
877 * o a negative error code is returned in case of failure.
878 */
879static int fallible_resolve_collision(struct ubifs_info *c,
880 const union ubifs_key *key,
881 struct ubifs_znode **zn, int *n,
882 const struct qstr *nm, int adding)
883{
884 struct ubifs_znode *o_znode = NULL, *znode = *zn;
885 int uninitialized_var(o_n), err, cmp, unsure = 0, nn = *n;
886
887 cmp = fallible_matches_name(c, &znode->zbranch[nn], nm);
888 if (unlikely(cmp < 0))
889 return cmp;
890 if (cmp == NAME_MATCHES)
891 return 1;
892 if (cmp == NOT_ON_MEDIA) {
893 o_znode = znode;
894 o_n = nn;
895 /*
896 * We are unlucky and hit a dangling branch straight away.
897 * Now we do not really know where to go to find the needed
898 * branch - to the left or to the right. Well, let's try left.
899 */
900 unsure = 1;
901 } else if (!adding)
902 unsure = 1; /* Remove a dangling branch wherever it is */
903
904 if (cmp == NAME_GREATER || unsure) {
905 /* Look left */
906 while (1) {
907 err = tnc_prev(c, zn, n);
908 if (err == -ENOENT) {
909 ubifs_assert(*n == 0);
910 *n = -1;
911 break;
912 }
913 if (err < 0)
914 return err;
915 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
916 /* See comments in 'resolve_collision()' */
917 if (*n == (*zn)->child_cnt - 1) {
918 err = tnc_next(c, zn, n);
919 if (err) {
920 /* Should be impossible */
921 ubifs_assert(0);
922 if (err == -ENOENT)
923 err = -EINVAL;
924 return err;
925 }
926 ubifs_assert(*n == 0);
927 *n = -1;
928 }
929 break;
930 }
931 err = fallible_matches_name(c, &(*zn)->zbranch[*n], nm);
932 if (err < 0)
933 return err;
934 if (err == NAME_MATCHES)
935 return 1;
936 if (err == NOT_ON_MEDIA) {
937 o_znode = *zn;
938 o_n = *n;
939 continue;
940 }
941 if (!adding)
942 continue;
943 if (err == NAME_LESS)
944 break;
945 else
946 unsure = 0;
947 }
948 }
949
950 if (cmp == NAME_LESS || unsure) {
951 /* Look right */
952 *zn = znode;
953 *n = nn;
954 while (1) {
955 err = tnc_next(c, &znode, &nn);
956 if (err == -ENOENT)
957 break;
958 if (err < 0)
959 return err;
960 if (keys_cmp(c, &znode->zbranch[nn].key, key))
961 break;
962 err = fallible_matches_name(c, &znode->zbranch[nn], nm);
963 if (err < 0)
964 return err;
965 if (err == NAME_GREATER)
966 break;
967 *zn = znode;
968 *n = nn;
969 if (err == NAME_MATCHES)
970 return 1;
971 if (err == NOT_ON_MEDIA) {
972 o_znode = znode;
973 o_n = nn;
974 }
975 }
976 }
977
978 /* Never match a dangling branch when adding */
979 if (adding || !o_znode)
980 return 0;
981
982 dbg_mntk(key, "dangling match LEB %d:%d len %d key ",
983 o_znode->zbranch[o_n].lnum, o_znode->zbranch[o_n].offs,
984 o_znode->zbranch[o_n].len);
985 *zn = o_znode;
986 *n = o_n;
987 return 1;
988}
989
990/**
991 * matches_position - determine if a zbranch matches a given position.
992 * @zbr: zbranch of dent
993 * @lnum: LEB number of dent to match
994 * @offs: offset of dent to match
995 *
996 * This function returns %1 if @lnum:@offs matches, and %0 otherwise.
997 */
998static int matches_position(struct ubifs_zbranch *zbr, int lnum, int offs)
999{
1000 if (zbr->lnum == lnum && zbr->offs == offs)
1001 return 1;
1002 else
1003 return 0;
1004}
1005
1006/**
1007 * resolve_collision_directly - resolve a collision directly.
1008 * @c: UBIFS file-system description object
1009 * @key: key of directory entry
1010 * @zn: znode is passed and returned here
1011 * @n: zbranch number is passed and returned here
1012 * @lnum: LEB number of dent node to match
1013 * @offs: offset of dent node to match
1014 *
1015 * This function is used for "hashed" keys to make sure the found directory or
1016 * extended attribute entry node is what was looked for. It is used when the
1017 * flash address of the right node is known (@lnum:@offs) which makes it much
1018 * easier to resolve collisions (no need to read entries and match full
1019 * names). This function returns %1 and sets @zn and @n if the collision is
1020 * resolved, %0 if @lnum:@offs is not found and @zn and @n are set to the
1021 * previous directory entry. Otherwise a negative error code is returned.
1022 */
1023static int resolve_collision_directly(struct ubifs_info *c,
1024 const union ubifs_key *key,
1025 struct ubifs_znode **zn, int *n,
1026 int lnum, int offs)
1027{
1028 struct ubifs_znode *znode;
1029 int nn, err;
1030
1031 znode = *zn;
1032 nn = *n;
1033 if (matches_position(&znode->zbranch[nn], lnum, offs))
1034 return 1;
1035
1036 /* Look left */
1037 while (1) {
1038 err = tnc_prev(c, &znode, &nn);
1039 if (err == -ENOENT)
1040 break;
1041 if (err < 0)
1042 return err;
1043 if (keys_cmp(c, &znode->zbranch[nn].key, key))
1044 break;
1045 if (matches_position(&znode->zbranch[nn], lnum, offs)) {
1046 *zn = znode;
1047 *n = nn;
1048 return 1;
1049 }
1050 }
1051
1052 /* Look right */
1053 znode = *zn;
1054 nn = *n;
1055 while (1) {
1056 err = tnc_next(c, &znode, &nn);
1057 if (err == -ENOENT)
1058 return 0;
1059 if (err < 0)
1060 return err;
1061 if (keys_cmp(c, &znode->zbranch[nn].key, key))
1062 return 0;
1063 *zn = znode;
1064 *n = nn;
1065 if (matches_position(&znode->zbranch[nn], lnum, offs))
1066 return 1;
1067 }
1068}
1069
1070/**
1071 * dirty_cow_bottom_up - dirty a znode and its ancestors.
1072 * @c: UBIFS file-system description object
1073 * @znode: znode to dirty
1074 *
1075 * If we do not have a unique key that resides in a znode, then we cannot
1076 * dirty that znode from the top down (i.e. by using lookup_level0_dirty)
1077 * This function records the path back to the last dirty ancestor, and then
1078 * dirties the znodes on that path.
1079 */
1080static struct ubifs_znode *dirty_cow_bottom_up(struct ubifs_info *c,
1081 struct ubifs_znode *znode)
1082{
1083 struct ubifs_znode *zp;
1084 int *path = c->bottom_up_buf, p = 0;
1085
1086 ubifs_assert(c->zroot.znode);
1087 ubifs_assert(znode);
1088 if (c->zroot.znode->level > BOTTOM_UP_HEIGHT) {
1089 kfree(c->bottom_up_buf);
1090 c->bottom_up_buf = kmalloc(c->zroot.znode->level * sizeof(int),
1091 GFP_NOFS);
1092 if (!c->bottom_up_buf)
1093 return ERR_PTR(-ENOMEM);
1094 path = c->bottom_up_buf;
1095 }
1096 if (c->zroot.znode->level) {
1097 /* Go up until parent is dirty */
1098 while (1) {
1099 int n;
1100
1101 zp = znode->parent;
1102 if (!zp)
1103 break;
1104 n = znode->iip;
1105 ubifs_assert(p < c->zroot.znode->level);
1106 path[p++] = n;
1107 if (!zp->cnext && ubifs_zn_dirty(znode))
1108 break;
1109 znode = zp;
1110 }
1111 }
1112
1113 /* Come back down, dirtying as we go */
1114 while (1) {
1115 struct ubifs_zbranch *zbr;
1116
1117 zp = znode->parent;
1118 if (zp) {
1119 ubifs_assert(path[p - 1] >= 0);
1120 ubifs_assert(path[p - 1] < zp->child_cnt);
1121 zbr = &zp->zbranch[path[--p]];
1122 znode = dirty_cow_znode(c, zbr);
1123 } else {
1124 ubifs_assert(znode == c->zroot.znode);
1125 znode = dirty_cow_znode(c, &c->zroot);
1126 }
1127 if (IS_ERR(znode) || !p)
1128 break;
1129 ubifs_assert(path[p - 1] >= 0);
1130 ubifs_assert(path[p - 1] < znode->child_cnt);
1131 znode = znode->zbranch[path[p - 1]].znode;
1132 }
1133
1134 return znode;
1135}
1136
1137/**
1138 * ubifs_lookup_level0 - search for zero-level znode.
1139 * @c: UBIFS file-system description object
1140 * @key: key to lookup
1141 * @zn: znode is returned here
1142 * @n: znode branch slot number is returned here
1143 *
1144 * This function looks up the TNC tree and search for zero-level znode which
1145 * refers key @key. The found zero-level znode is returned in @zn. There are 3
1146 * cases:
1147 * o exact match, i.e. the found zero-level znode contains key @key, then %1
1148 * is returned and slot number of the matched branch is stored in @n;
1149 * o not exact match, which means that zero-level znode does not contain
1150 * @key, then %0 is returned and slot number of the closest branch is stored
1151 * in @n;
1152 * o @key is so small that it is even less than the lowest key of the
1153 * leftmost zero-level node, then %0 is returned and %0 is stored in @n.
1154 *
1155 * Note, when the TNC tree is traversed, some znodes may be absent, then this
1156 * function reads corresponding indexing nodes and inserts them to TNC. In
1157 * case of failure, a negative error code is returned.
1158 */
1159int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
1160 struct ubifs_znode **zn, int *n)
1161{
1162 int err, exact;
1163 struct ubifs_znode *znode;
1164 unsigned long time = get_seconds();
1165
1166 dbg_tnck(key, "search key ");
1167 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
1168
1169 znode = c->zroot.znode;
1170 if (unlikely(!znode)) {
1171 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
1172 if (IS_ERR(znode))
1173 return PTR_ERR(znode);
1174 }
1175
1176 znode->time = time;
1177
1178 while (1) {
1179 struct ubifs_zbranch *zbr;
1180
1181 exact = ubifs_search_zbranch(c, znode, key, n);
1182
1183 if (znode->level == 0)
1184 break;
1185
1186 if (*n < 0)
1187 *n = 0;
1188 zbr = &znode->zbranch[*n];
1189
1190 if (zbr->znode) {
1191 znode->time = time;
1192 znode = zbr->znode;
1193 continue;
1194 }
1195
1196 /* znode is not in TNC cache, load it from the media */
1197 znode = ubifs_load_znode(c, zbr, znode, *n);
1198 if (IS_ERR(znode))
1199 return PTR_ERR(znode);
1200 }
1201
1202 *zn = znode;
1203 if (exact || !is_hash_key(c, key) || *n != -1) {
1204 dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
1205 return exact;
1206 }
1207
1208 /*
1209 * Here is a tricky place. We have not found the key and this is a
1210 * "hashed" key, which may collide. The rest of the code deals with
1211 * situations like this:
1212 *
1213 * | 3 | 5 |
1214 * / \
1215 * | 3 | 5 | | 6 | 7 | (x)
1216 *
1217 * Or more a complex example:
1218 *
1219 * | 1 | 5 |
1220 * / \
1221 * | 1 | 3 | | 5 | 8 |
1222 * \ /
1223 * | 5 | 5 | | 6 | 7 | (x)
1224 *
1225 * In the examples, if we are looking for key "5", we may reach nodes
1226 * marked with "(x)". In this case what we have do is to look at the
1227 * left and see if there is "5" key there. If there is, we have to
1228 * return it.
1229 *
1230 * Note, this whole situation is possible because we allow to have
1231 * elements which are equivalent to the next key in the parent in the
1232 * children of current znode. For example, this happens if we split a
1233 * znode like this: | 3 | 5 | 5 | 6 | 7 |, which results in something
1234 * like this:
1235 * | 3 | 5 |
1236 * / \
1237 * | 3 | 5 | | 5 | 6 | 7 |
1238 * ^
1239 * And this becomes what is at the first "picture" after key "5" marked
1240 * with "^" is removed. What could be done is we could prohibit
1241 * splitting in the middle of the colliding sequence. Also, when
1242 * removing the leftmost key, we would have to correct the key of the
1243 * parent node, which would introduce additional complications. Namely,
1244 * if we changed the leftmost key of the parent znode, the garbage
1245 * collector would be unable to find it (GC is doing this when GC'ing
1246 * indexing LEBs). Although we already have an additional RB-tree where
1247 * we save such changed znodes (see 'ins_clr_old_idx_znode()') until
1248 * after the commit. But anyway, this does not look easy to implement
1249 * so we did not try this.
1250 */
1251 err = tnc_prev(c, &znode, n);
1252 if (err == -ENOENT) {
1253 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1254 *n = -1;
1255 return 0;
1256 }
1257 if (unlikely(err < 0))
1258 return err;
1259 if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
1260 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1261 *n = -1;
1262 return 0;
1263 }
1264
1265 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1266 *zn = znode;
1267 return 1;
1268}
1269
1270/**
1271 * lookup_level0_dirty - search for zero-level znode dirtying.
1272 * @c: UBIFS file-system description object
1273 * @key: key to lookup
1274 * @zn: znode is returned here
1275 * @n: znode branch slot number is returned here
1276 *
1277 * This function looks up the TNC tree and search for zero-level znode which
1278 * refers key @key. The found zero-level znode is returned in @zn. There are 3
1279 * cases:
1280 * o exact match, i.e. the found zero-level znode contains key @key, then %1
1281 * is returned and slot number of the matched branch is stored in @n;
1282 * o not exact match, which means that zero-level znode does not contain @key
1283 * then %0 is returned and slot number of the closed branch is stored in
1284 * @n;
1285 * o @key is so small that it is even less than the lowest key of the
1286 * leftmost zero-level node, then %0 is returned and %-1 is stored in @n.
1287 *
1288 * Additionally all znodes in the path from the root to the located zero-level
1289 * znode are marked as dirty.
1290 *
1291 * Note, when the TNC tree is traversed, some znodes may be absent, then this
1292 * function reads corresponding indexing nodes and inserts them to TNC. In
1293 * case of failure, a negative error code is returned.
1294 */
1295static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key,
1296 struct ubifs_znode **zn, int *n)
1297{
1298 int err, exact;
1299 struct ubifs_znode *znode;
1300 unsigned long time = get_seconds();
1301
1302 dbg_tnck(key, "search and dirty key ");
1303
1304 znode = c->zroot.znode;
1305 if (unlikely(!znode)) {
1306 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
1307 if (IS_ERR(znode))
1308 return PTR_ERR(znode);
1309 }
1310
1311 znode = dirty_cow_znode(c, &c->zroot);
1312 if (IS_ERR(znode))
1313 return PTR_ERR(znode);
1314
1315 znode->time = time;
1316
1317 while (1) {
1318 struct ubifs_zbranch *zbr;
1319
1320 exact = ubifs_search_zbranch(c, znode, key, n);
1321
1322 if (znode->level == 0)
1323 break;
1324
1325 if (*n < 0)
1326 *n = 0;
1327 zbr = &znode->zbranch[*n];
1328
1329 if (zbr->znode) {
1330 znode->time = time;
1331 znode = dirty_cow_znode(c, zbr);
1332 if (IS_ERR(znode))
1333 return PTR_ERR(znode);
1334 continue;
1335 }
1336
1337 /* znode is not in TNC cache, load it from the media */
1338 znode = ubifs_load_znode(c, zbr, znode, *n);
1339 if (IS_ERR(znode))
1340 return PTR_ERR(znode);
1341 znode = dirty_cow_znode(c, zbr);
1342 if (IS_ERR(znode))
1343 return PTR_ERR(znode);
1344 }
1345
1346 *zn = znode;
1347 if (exact || !is_hash_key(c, key) || *n != -1) {
1348 dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
1349 return exact;
1350 }
1351
1352 /*
1353 * See huge comment at 'lookup_level0_dirty()' what is the rest of the
1354 * code.
1355 */
1356 err = tnc_prev(c, &znode, n);
1357 if (err == -ENOENT) {
1358 *n = -1;
1359 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1360 return 0;
1361 }
1362 if (unlikely(err < 0))
1363 return err;
1364 if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
1365 *n = -1;
1366 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1367 return 0;
1368 }
1369
1370 if (znode->cnext || !ubifs_zn_dirty(znode)) {
1371 znode = dirty_cow_bottom_up(c, znode);
1372 if (IS_ERR(znode))
1373 return PTR_ERR(znode);
1374 }
1375
1376 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1377 *zn = znode;
1378 return 1;
1379}
1380
1381/**
1382 * maybe_leb_gced - determine if a LEB may have been garbage collected.
1383 * @c: UBIFS file-system description object
1384 * @lnum: LEB number
1385 * @gc_seq1: garbage collection sequence number
1386 *
1387 * This function determines if @lnum may have been garbage collected since
1388 * sequence number @gc_seq1. If it may have been then %1 is returned, otherwise
1389 * %0 is returned.
1390 */
1391static int maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1)
1392{
1393 int gc_seq2, gced_lnum;
1394
1395 gced_lnum = c->gced_lnum;
1396 smp_rmb();
1397 gc_seq2 = c->gc_seq;
1398 /* Same seq means no GC */
1399 if (gc_seq1 == gc_seq2)
1400 return 0;
1401 /* Different by more than 1 means we don't know */
1402 if (gc_seq1 + 1 != gc_seq2)
1403 return 1;
1404 /*
1405 * We have seen the sequence number has increased by 1. Now we need to
1406 * be sure we read the right LEB number, so read it again.
1407 */
1408 smp_rmb();
1409 if (gced_lnum != c->gced_lnum)
1410 return 1;
1411 /* Finally we can check lnum */
1412 if (gced_lnum == lnum)
1413 return 1;
1414 return 0;
1415}
1416
1417/**
1418 * ubifs_tnc_locate - look up a file-system node and return it and its location.
1419 * @c: UBIFS file-system description object
1420 * @key: node key to lookup
1421 * @node: the node is returned here
1422 * @lnum: LEB number is returned here
1423 * @offs: offset is returned here
1424 *
1425 * This function looks up and reads node with key @key. The caller has to make
1426 * sure the @node buffer is large enough to fit the node. Returns zero in case
1427 * of success, %-ENOENT if the node was not found, and a negative error code in
1428 * case of failure. The node location can be returned in @lnum and @offs.
1429 */
1430int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key,
1431 void *node, int *lnum, int *offs)
1432{
1433 int found, n, err, safely = 0, gc_seq1;
1434 struct ubifs_znode *znode;
1435 struct ubifs_zbranch zbr, *zt;
1436
1437again:
1438 mutex_lock(&c->tnc_mutex);
1439 found = ubifs_lookup_level0(c, key, &znode, &n);
1440 if (!found) {
1441 err = -ENOENT;
1442 goto out;
1443 } else if (found < 0) {
1444 err = found;
1445 goto out;
1446 }
1447 zt = &znode->zbranch[n];
1448 if (lnum) {
1449 *lnum = zt->lnum;
1450 *offs = zt->offs;
1451 }
1452 if (is_hash_key(c, key)) {
1453 /*
1454 * In this case the leaf node cache gets used, so we pass the
1455 * address of the zbranch and keep the mutex locked
1456 */
1457 err = tnc_read_node_nm(c, zt, node);
1458 goto out;
1459 }
1460 if (safely) {
1461 err = ubifs_tnc_read_node(c, zt, node);
1462 goto out;
1463 }
1464 /* Drop the TNC mutex prematurely and race with garbage collection */
1465 zbr = znode->zbranch[n];
1466 gc_seq1 = c->gc_seq;
1467 mutex_unlock(&c->tnc_mutex);
1468
1469 if (ubifs_get_wbuf(c, zbr.lnum)) {
1470 /* We do not GC journal heads */
1471 err = ubifs_tnc_read_node(c, &zbr, node);
1472 return err;
1473 }
1474
1475 err = fallible_read_node(c, key, &zbr, node);
1476 if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) {
1477 /*
1478 * The node may have been GC'ed out from under us so try again
1479 * while keeping the TNC mutex locked.
1480 */
1481 safely = 1;
1482 goto again;
1483 }
1484 return 0;
1485
1486out:
1487 mutex_unlock(&c->tnc_mutex);
1488 return err;
1489}
1490
1491/**
1492 * ubifs_tnc_get_bu_keys - lookup keys for bulk-read.
1493 * @c: UBIFS file-system description object
1494 * @bu: bulk-read parameters and results
1495 *
1496 * Lookup consecutive data node keys for the same inode that reside
1497 * consecutively in the same LEB. This function returns zero in case of success
1498 * and a negative error code in case of failure.
1499 *
1500 * Note, if the bulk-read buffer length (@bu->buf_len) is known, this function
1501 * makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares
1502 * maximum possible amount of nodes for bulk-read.
1503 */
1504int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)
1505{
1506 int n, err = 0, lnum = -1, uninitialized_var(offs);
1507 int uninitialized_var(len);
1508 unsigned int block = key_block(c, &bu->key);
1509 struct ubifs_znode *znode;
1510
1511 bu->cnt = 0;
1512 bu->blk_cnt = 0;
1513 bu->eof = 0;
1514
1515 mutex_lock(&c->tnc_mutex);
1516 /* Find first key */
1517 err = ubifs_lookup_level0(c, &bu->key, &znode, &n);
1518 if (err < 0)
1519 goto out;
1520 if (err) {
1521 /* Key found */
1522 len = znode->zbranch[n].len;
1523 /* The buffer must be big enough for at least 1 node */
1524 if (len > bu->buf_len) {
1525 err = -EINVAL;
1526 goto out;
1527 }
1528 /* Add this key */
1529 bu->zbranch[bu->cnt++] = znode->zbranch[n];
1530 bu->blk_cnt += 1;
1531 lnum = znode->zbranch[n].lnum;
1532 offs = ALIGN(znode->zbranch[n].offs + len, 8);
1533 }
1534 while (1) {
1535 struct ubifs_zbranch *zbr;
1536 union ubifs_key *key;
1537 unsigned int next_block;
1538
1539 /* Find next key */
1540 err = tnc_next(c, &znode, &n);
1541 if (err)
1542 goto out;
1543 zbr = &znode->zbranch[n];
1544 key = &zbr->key;
1545 /* See if there is another data key for this file */
1546 if (key_inum(c, key) != key_inum(c, &bu->key) ||
1547 key_type(c, key) != UBIFS_DATA_KEY) {
1548 err = -ENOENT;
1549 goto out;
1550 }
1551 if (lnum < 0) {
1552 /* First key found */
1553 lnum = zbr->lnum;
1554 offs = ALIGN(zbr->offs + zbr->len, 8);
1555 len = zbr->len;
1556 if (len > bu->buf_len) {
1557 err = -EINVAL;
1558 goto out;
1559 }
1560 } else {
1561 /*
1562 * The data nodes must be in consecutive positions in
1563 * the same LEB.
1564 */
1565 if (zbr->lnum != lnum || zbr->offs != offs)
1566 goto out;
1567 offs += ALIGN(zbr->len, 8);
1568 len = ALIGN(len, 8) + zbr->len;
1569 /* Must not exceed buffer length */
1570 if (len > bu->buf_len)
1571 goto out;
1572 }
1573 /* Allow for holes */
1574 next_block = key_block(c, key);
1575 bu->blk_cnt += (next_block - block - 1);
1576 if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
1577 goto out;
1578 block = next_block;
1579 /* Add this key */
1580 bu->zbranch[bu->cnt++] = *zbr;
1581 bu->blk_cnt += 1;
1582 /* See if we have room for more */
1583 if (bu->cnt >= UBIFS_MAX_BULK_READ)
1584 goto out;
1585 if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
1586 goto out;
1587 }
1588out:
1589 if (err == -ENOENT) {
1590 bu->eof = 1;
1591 err = 0;
1592 }
1593 bu->gc_seq = c->gc_seq;
1594 mutex_unlock(&c->tnc_mutex);
1595 if (err)
1596 return err;
1597 /*
1598 * An enormous hole could cause bulk-read to encompass too many
1599 * page cache pages, so limit the number here.
1600 */
1601 if (bu->blk_cnt > UBIFS_MAX_BULK_READ)
1602 bu->blk_cnt = UBIFS_MAX_BULK_READ;
1603 /*
1604 * Ensure that bulk-read covers a whole number of page cache
1605 * pages.
1606 */
1607 if (UBIFS_BLOCKS_PER_PAGE == 1 ||
1608 !(bu->blk_cnt & (UBIFS_BLOCKS_PER_PAGE - 1)))
1609 return 0;
1610 if (bu->eof) {
1611 /* At the end of file we can round up */
1612 bu->blk_cnt += UBIFS_BLOCKS_PER_PAGE - 1;
1613 return 0;
1614 }
1615 /* Exclude data nodes that do not make up a whole page cache page */
1616 block = key_block(c, &bu->key) + bu->blk_cnt;
1617 block &= ~(UBIFS_BLOCKS_PER_PAGE - 1);
1618 while (bu->cnt) {
1619 if (key_block(c, &bu->zbranch[bu->cnt - 1].key) < block)
1620 break;
1621 bu->cnt -= 1;
1622 }
1623 return 0;
1624}
1625
1626/**
1627 * read_wbuf - bulk-read from a LEB with a wbuf.
1628 * @wbuf: wbuf that may overlap the read
1629 * @buf: buffer into which to read
1630 * @len: read length
1631 * @lnum: LEB number from which to read
1632 * @offs: offset from which to read
1633 *
1634 * This functions returns %0 on success or a negative error code on failure.
1635 */
1636static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum,
1637 int offs)
1638{
1639 const struct ubifs_info *c = wbuf->c;
1640 int rlen, overlap;
1641
1642 dbg_io("LEB %d:%d, length %d", lnum, offs, len);
1643 ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
1644 ubifs_assert(!(offs & 7) && offs < c->leb_size);
1645 ubifs_assert(offs + len <= c->leb_size);
1646
1647 spin_lock(&wbuf->lock);
1648 overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
1649 if (!overlap) {
1650 /* We may safely unlock the write-buffer and read the data */
1651 spin_unlock(&wbuf->lock);
1652 return ubifs_leb_read(c, lnum, buf, offs, len, 0);
1653 }
1654
1655 /* Don't read under wbuf */
1656 rlen = wbuf->offs - offs;
1657 if (rlen < 0)
1658 rlen = 0;
1659
1660 /* Copy the rest from the write-buffer */
1661 memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
1662 spin_unlock(&wbuf->lock);
1663
1664 if (rlen > 0)
1665 /* Read everything that goes before write-buffer */
1666 return ubifs_leb_read(c, lnum, buf, offs, rlen, 0);
1667
1668 return 0;
1669}
1670
1671/**
1672 * validate_data_node - validate data nodes for bulk-read.
1673 * @c: UBIFS file-system description object
1674 * @buf: buffer containing data node to validate
1675 * @zbr: zbranch of data node to validate
1676 *
1677 * This functions returns %0 on success or a negative error code on failure.
1678 */
1679static int validate_data_node(struct ubifs_info *c, void *buf,
1680 struct ubifs_zbranch *zbr)
1681{
1682 union ubifs_key key1;
1683 struct ubifs_ch *ch = buf;
1684 int err, len;
1685
1686 if (ch->node_type != UBIFS_DATA_NODE) {
1687 ubifs_err("bad node type (%d but expected %d)",
1688 ch->node_type, UBIFS_DATA_NODE);
1689 goto out_err;
1690 }
1691
1692 err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0, 0);
1693 if (err) {
1694 ubifs_err("expected node type %d", UBIFS_DATA_NODE);
1695 goto out;
1696 }
1697
1698 len = le32_to_cpu(ch->len);
1699 if (len != zbr->len) {
1700 ubifs_err("bad node length %d, expected %d", len, zbr->len);
1701 goto out_err;
1702 }
1703
1704 /* Make sure the key of the read node is correct */
1705 key_read(c, buf + UBIFS_KEY_OFFSET, &key1);
1706 if (!keys_eq(c, &zbr->key, &key1)) {
1707 ubifs_err("bad key in node at LEB %d:%d",
1708 zbr->lnum, zbr->offs);
1709 dbg_tnck(&zbr->key, "looked for key ");
1710 dbg_tnck(&key1, "found node's key ");
1711 goto out_err;
1712 }
1713
1714 return 0;
1715
1716out_err:
1717 err = -EINVAL;
1718out:
1719 ubifs_err("bad node at LEB %d:%d", zbr->lnum, zbr->offs);
1720 ubifs_dump_node(c, buf);
1721 dump_stack();
1722 return err;
1723}
1724
1725/**
1726 * ubifs_tnc_bulk_read - read a number of data nodes in one go.
1727 * @c: UBIFS file-system description object
1728 * @bu: bulk-read parameters and results
1729 *
1730 * This functions reads and validates the data nodes that were identified by the
1731 * 'ubifs_tnc_get_bu_keys()' function. This functions returns %0 on success,
1732 * -EAGAIN to indicate a race with GC, or another negative error code on
1733 * failure.
1734 */
1735int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu)
1736{
1737 int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i;
1738 struct ubifs_wbuf *wbuf;
1739 void *buf;
1740
1741 len = bu->zbranch[bu->cnt - 1].offs;
1742 len += bu->zbranch[bu->cnt - 1].len - offs;
1743 if (len > bu->buf_len) {
1744 ubifs_err("buffer too small %d vs %d", bu->buf_len, len);
1745 return -EINVAL;
1746 }
1747
1748 /* Do the read */
1749 wbuf = ubifs_get_wbuf(c, lnum);
1750 if (wbuf)
1751 err = read_wbuf(wbuf, bu->buf, len, lnum, offs);
1752 else
1753 err = ubifs_leb_read(c, lnum, bu->buf, offs, len, 0);
1754
1755 /* Check for a race with GC */
1756 if (maybe_leb_gced(c, lnum, bu->gc_seq))
1757 return -EAGAIN;
1758
1759 if (err && err != -EBADMSG) {
1760 ubifs_err("failed to read from LEB %d:%d, error %d",
1761 lnum, offs, err);
1762 dump_stack();
1763 dbg_tnck(&bu->key, "key ");
1764 return err;
1765 }
1766
1767 /* Validate the nodes read */
1768 buf = bu->buf;
1769 for (i = 0; i < bu->cnt; i++) {
1770 err = validate_data_node(c, buf, &bu->zbranch[i]);
1771 if (err)
1772 return err;
1773 buf = buf + ALIGN(bu->zbranch[i].len, 8);
1774 }
1775
1776 return 0;
1777}
1778
1779/**
1780 * do_lookup_nm- look up a "hashed" node.
1781 * @c: UBIFS file-system description object
1782 * @key: node key to lookup
1783 * @node: the node is returned here
1784 * @nm: node name
1785 *
1786 * This function look up and reads a node which contains name hash in the key.
1787 * Since the hash may have collisions, there may be many nodes with the same
1788 * key, so we have to sequentially look to all of them until the needed one is
1789 * found. This function returns zero in case of success, %-ENOENT if the node
1790 * was not found, and a negative error code in case of failure.
1791 */
1792static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1793 void *node, const struct qstr *nm)
1794{
1795 int found, n, err;
1796 struct ubifs_znode *znode;
1797
1798 dbg_tnck(key, "name '%.*s' key ", nm->len, nm->name);
1799 mutex_lock(&c->tnc_mutex);
1800 found = ubifs_lookup_level0(c, key, &znode, &n);
1801 if (!found) {
1802 err = -ENOENT;
1803 goto out_unlock;
1804 } else if (found < 0) {
1805 err = found;
1806 goto out_unlock;
1807 }
1808
1809 ubifs_assert(n >= 0);
1810
1811 err = resolve_collision(c, key, &znode, &n, nm);
1812 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
1813 if (unlikely(err < 0))
1814 goto out_unlock;
1815 if (err == 0) {
1816 err = -ENOENT;
1817 goto out_unlock;
1818 }
1819
1820 err = tnc_read_node_nm(c, &znode->zbranch[n], node);
1821
1822out_unlock:
1823 mutex_unlock(&c->tnc_mutex);
1824 return err;
1825}
1826
1827/**
1828 * ubifs_tnc_lookup_nm - look up a "hashed" node.
1829 * @c: UBIFS file-system description object
1830 * @key: node key to lookup
1831 * @node: the node is returned here
1832 * @nm: node name
1833 *
1834 * This function look up and reads a node which contains name hash in the key.
1835 * Since the hash may have collisions, there may be many nodes with the same
1836 * key, so we have to sequentially look to all of them until the needed one is
1837 * found. This function returns zero in case of success, %-ENOENT if the node
1838 * was not found, and a negative error code in case of failure.
1839 */
1840int ubifs_tnc_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1841 void *node, const struct qstr *nm)
1842{
1843 int err, len;
1844 const struct ubifs_dent_node *dent = node;
1845
1846 /*
1847 * We assume that in most of the cases there are no name collisions and
1848 * 'ubifs_tnc_lookup()' returns us the right direntry.
1849 */
1850 err = ubifs_tnc_lookup(c, key, node);
1851 if (err)
1852 return err;
1853
1854 len = le16_to_cpu(dent->nlen);
1855 if (nm->len == len && !memcmp(dent->name, nm->name, len))
1856 return 0;
1857
1858 /*
1859 * Unluckily, there are hash collisions and we have to iterate over
1860 * them look at each direntry with colliding name hash sequentially.
1861 */
1862 return do_lookup_nm(c, key, node, nm);
1863}
1864
1865/**
1866 * correct_parent_keys - correct parent znodes' keys.
1867 * @c: UBIFS file-system description object
1868 * @znode: znode to correct parent znodes for
1869 *
1870 * This is a helper function for 'tnc_insert()'. When the key of the leftmost
1871 * zbranch changes, keys of parent znodes have to be corrected. This helper
1872 * function is called in such situations and corrects the keys if needed.
1873 */
1874static void correct_parent_keys(const struct ubifs_info *c,
1875 struct ubifs_znode *znode)
1876{
1877 union ubifs_key *key, *key1;
1878
1879 ubifs_assert(znode->parent);
1880 ubifs_assert(znode->iip == 0);
1881
1882 key = &znode->zbranch[0].key;
1883 key1 = &znode->parent->zbranch[0].key;
1884
1885 while (keys_cmp(c, key, key1) < 0) {
1886 key_copy(c, key, key1);
1887 znode = znode->parent;
1888 znode->alt = 1;
1889 if (!znode->parent || znode->iip)
1890 break;
1891 key1 = &znode->parent->zbranch[0].key;
1892 }
1893}
1894
1895/**
1896 * insert_zbranch - insert a zbranch into a znode.
1897 * @znode: znode into which to insert
1898 * @zbr: zbranch to insert
1899 * @n: slot number to insert to
1900 *
1901 * This is a helper function for 'tnc_insert()'. UBIFS does not allow "gaps" in
1902 * znode's array of zbranches and keeps zbranches consolidated, so when a new
1903 * zbranch has to be inserted to the @znode->zbranches[]' array at the @n-th
1904 * slot, zbranches starting from @n have to be moved right.
1905 */
1906static void insert_zbranch(struct ubifs_znode *znode,
1907 const struct ubifs_zbranch *zbr, int n)
1908{
1909 int i;
1910
1911 ubifs_assert(ubifs_zn_dirty(znode));
1912
1913 if (znode->level) {
1914 for (i = znode->child_cnt; i > n; i--) {
1915 znode->zbranch[i] = znode->zbranch[i - 1];
1916 if (znode->zbranch[i].znode)
1917 znode->zbranch[i].znode->iip = i;
1918 }
1919 if (zbr->znode)
1920 zbr->znode->iip = n;
1921 } else
1922 for (i = znode->child_cnt; i > n; i--)
1923 znode->zbranch[i] = znode->zbranch[i - 1];
1924
1925 znode->zbranch[n] = *zbr;
1926 znode->child_cnt += 1;
1927
1928 /*
1929 * After inserting at slot zero, the lower bound of the key range of
1930 * this znode may have changed. If this znode is subsequently split
1931 * then the upper bound of the key range may change, and furthermore
1932 * it could change to be lower than the original lower bound. If that
1933 * happens, then it will no longer be possible to find this znode in the
1934 * TNC using the key from the index node on flash. That is bad because
1935 * if it is not found, we will assume it is obsolete and may overwrite
1936 * it. Then if there is an unclean unmount, we will start using the
1937 * old index which will be broken.
1938 *
1939 * So we first mark znodes that have insertions at slot zero, and then
1940 * if they are split we add their lnum/offs to the old_idx tree.
1941 */
1942 if (n == 0)
1943 znode->alt = 1;
1944}
1945
1946/**
1947 * tnc_insert - insert a node into TNC.
1948 * @c: UBIFS file-system description object
1949 * @znode: znode to insert into
1950 * @zbr: branch to insert
1951 * @n: slot number to insert new zbranch to
1952 *
1953 * This function inserts a new node described by @zbr into znode @znode. If
1954 * znode does not have a free slot for new zbranch, it is split. Parent znodes
1955 * are splat as well if needed. Returns zero in case of success or a negative
1956 * error code in case of failure.
1957 */
1958static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode,
1959 struct ubifs_zbranch *zbr, int n)
1960{
1961 struct ubifs_znode *zn, *zi, *zp;
1962 int i, keep, move, appending = 0;
1963 union ubifs_key *key = &zbr->key, *key1;
1964
1965 ubifs_assert(n >= 0 && n <= c->fanout);
1966
1967 /* Implement naive insert for now */
1968again:
1969 zp = znode->parent;
1970 if (znode->child_cnt < c->fanout) {
1971 ubifs_assert(n != c->fanout);
1972 dbg_tnck(key, "inserted at %d level %d, key ", n, znode->level);
1973
1974 insert_zbranch(znode, zbr, n);
1975
1976 /* Ensure parent's key is correct */
1977 if (n == 0 && zp && znode->iip == 0)
1978 correct_parent_keys(c, znode);
1979
1980 return 0;
1981 }
1982
1983 /*
1984 * Unfortunately, @znode does not have more empty slots and we have to
1985 * split it.
1986 */
1987 dbg_tnck(key, "splitting level %d, key ", znode->level);
1988
1989 if (znode->alt)
1990 /*
1991 * We can no longer be sure of finding this znode by key, so we
1992 * record it in the old_idx tree.
1993 */
1994 ins_clr_old_idx_znode(c, znode);
1995
1996 zn = kzalloc(c->max_znode_sz, GFP_NOFS);
1997 if (!zn)
1998 return -ENOMEM;
1999 zn->parent = zp;
2000 zn->level = znode->level;
2001
2002 /* Decide where to split */
2003 if (znode->level == 0 && key_type(c, key) == UBIFS_DATA_KEY) {
2004 /* Try not to split consecutive data keys */
2005 if (n == c->fanout) {
2006 key1 = &znode->zbranch[n - 1].key;
2007 if (key_inum(c, key1) == key_inum(c, key) &&
2008 key_type(c, key1) == UBIFS_DATA_KEY)
2009 appending = 1;
2010 } else
2011 goto check_split;
2012 } else if (appending && n != c->fanout) {
2013 /* Try not to split consecutive data keys */
2014 appending = 0;
2015check_split:
2016 if (n >= (c->fanout + 1) / 2) {
2017 key1 = &znode->zbranch[0].key;
2018 if (key_inum(c, key1) == key_inum(c, key) &&
2019 key_type(c, key1) == UBIFS_DATA_KEY) {
2020 key1 = &znode->zbranch[n].key;
2021 if (key_inum(c, key1) != key_inum(c, key) ||
2022 key_type(c, key1) != UBIFS_DATA_KEY) {
2023 keep = n;
2024 move = c->fanout - keep;
2025 zi = znode;
2026 goto do_split;
2027 }
2028 }
2029 }
2030 }
2031
2032 if (appending) {
2033 keep = c->fanout;
2034 move = 0;
2035 } else {
2036 keep = (c->fanout + 1) / 2;
2037 move = c->fanout - keep;
2038 }
2039
2040 /*
2041 * Although we don't at present, we could look at the neighbors and see
2042 * if we can move some zbranches there.
2043 */
2044
2045 if (n < keep) {
2046 /* Insert into existing znode */
2047 zi = znode;
2048 move += 1;
2049 keep -= 1;
2050 } else {
2051 /* Insert into new znode */
2052 zi = zn;
2053 n -= keep;
2054 /* Re-parent */
2055 if (zn->level != 0)
2056 zbr->znode->parent = zn;
2057 }
2058
2059do_split:
2060
2061 __set_bit(DIRTY_ZNODE, &zn->flags);
2062 atomic_long_inc(&c->dirty_zn_cnt);
2063
2064 zn->child_cnt = move;
2065 znode->child_cnt = keep;
2066
2067 dbg_tnc("moving %d, keeping %d", move, keep);
2068
2069 /* Move zbranch */
2070 for (i = 0; i < move; i++) {
2071 zn->zbranch[i] = znode->zbranch[keep + i];
2072 /* Re-parent */
2073 if (zn->level != 0)
2074 if (zn->zbranch[i].znode) {
2075 zn->zbranch[i].znode->parent = zn;
2076 zn->zbranch[i].znode->iip = i;
2077 }
2078 }
2079
2080 /* Insert new key and branch */
2081 dbg_tnck(key, "inserting at %d level %d, key ", n, zn->level);
2082
2083 insert_zbranch(zi, zbr, n);
2084
2085 /* Insert new znode (produced by spitting) into the parent */
2086 if (zp) {
2087 if (n == 0 && zi == znode && znode->iip == 0)
2088 correct_parent_keys(c, znode);
2089
2090 /* Locate insertion point */
2091 n = znode->iip + 1;
2092
2093 /* Tail recursion */
2094 zbr->key = zn->zbranch[0].key;
2095 zbr->znode = zn;
2096 zbr->lnum = 0;
2097 zbr->offs = 0;
2098 zbr->len = 0;
2099 znode = zp;
2100
2101 goto again;
2102 }
2103
2104 /* We have to split root znode */
2105 dbg_tnc("creating new zroot at level %d", znode->level + 1);
2106
2107 zi = kzalloc(c->max_znode_sz, GFP_NOFS);
2108 if (!zi)
2109 return -ENOMEM;
2110
2111 zi->child_cnt = 2;
2112 zi->level = znode->level + 1;
2113
2114 __set_bit(DIRTY_ZNODE, &zi->flags);
2115 atomic_long_inc(&c->dirty_zn_cnt);
2116
2117 zi->zbranch[0].key = znode->zbranch[0].key;
2118 zi->zbranch[0].znode = znode;
2119 zi->zbranch[0].lnum = c->zroot.lnum;
2120 zi->zbranch[0].offs = c->zroot.offs;
2121 zi->zbranch[0].len = c->zroot.len;
2122 zi->zbranch[1].key = zn->zbranch[0].key;
2123 zi->zbranch[1].znode = zn;
2124
2125 c->zroot.lnum = 0;
2126 c->zroot.offs = 0;
2127 c->zroot.len = 0;
2128 c->zroot.znode = zi;
2129
2130 zn->parent = zi;
2131 zn->iip = 1;
2132 znode->parent = zi;
2133 znode->iip = 0;
2134
2135 return 0;
2136}
2137
2138/**
2139 * ubifs_tnc_add - add a node to TNC.
2140 * @c: UBIFS file-system description object
2141 * @key: key to add
2142 * @lnum: LEB number of node
2143 * @offs: node offset
2144 * @len: node length
2145 *
2146 * This function adds a node with key @key to TNC. The node may be new or it may
2147 * obsolete some existing one. Returns %0 on success or negative error code on
2148 * failure.
2149 */
2150int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum,
2151 int offs, int len)
2152{
2153 int found, n, err = 0;
2154 struct ubifs_znode *znode;
2155
2156 mutex_lock(&c->tnc_mutex);
2157 dbg_tnck(key, "%d:%d, len %d, key ", lnum, offs, len);
2158 found = lookup_level0_dirty(c, key, &znode, &n);
2159 if (!found) {
2160 struct ubifs_zbranch zbr;
2161
2162 zbr.znode = NULL;
2163 zbr.lnum = lnum;
2164 zbr.offs = offs;
2165 zbr.len = len;
2166 key_copy(c, key, &zbr.key);
2167 err = tnc_insert(c, znode, &zbr, n + 1);
2168 } else if (found == 1) {
2169 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2170
2171 lnc_free(zbr);
2172 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2173 zbr->lnum = lnum;
2174 zbr->offs = offs;
2175 zbr->len = len;
2176 } else
2177 err = found;
2178 if (!err)
2179 err = dbg_check_tnc(c, 0);
2180 mutex_unlock(&c->tnc_mutex);
2181
2182 return err;
2183}
2184
2185/**
2186 * ubifs_tnc_replace - replace a node in the TNC only if the old node is found.
2187 * @c: UBIFS file-system description object
2188 * @key: key to add
2189 * @old_lnum: LEB number of old node
2190 * @old_offs: old node offset
2191 * @lnum: LEB number of node
2192 * @offs: node offset
2193 * @len: node length
2194 *
2195 * This function replaces a node with key @key in the TNC only if the old node
2196 * is found. This function is called by garbage collection when node are moved.
2197 * Returns %0 on success or negative error code on failure.
2198 */
2199int ubifs_tnc_replace(struct ubifs_info *c, const union ubifs_key *key,
2200 int old_lnum, int old_offs, int lnum, int offs, int len)
2201{
2202 int found, n, err = 0;
2203 struct ubifs_znode *znode;
2204
2205 mutex_lock(&c->tnc_mutex);
2206 dbg_tnck(key, "old LEB %d:%d, new LEB %d:%d, len %d, key ", old_lnum,
2207 old_offs, lnum, offs, len);
2208 found = lookup_level0_dirty(c, key, &znode, &n);
2209 if (found < 0) {
2210 err = found;
2211 goto out_unlock;
2212 }
2213
2214 if (found == 1) {
2215 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2216
2217 found = 0;
2218 if (zbr->lnum == old_lnum && zbr->offs == old_offs) {
2219 lnc_free(zbr);
2220 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2221 if (err)
2222 goto out_unlock;
2223 zbr->lnum = lnum;
2224 zbr->offs = offs;
2225 zbr->len = len;
2226 found = 1;
2227 } else if (is_hash_key(c, key)) {
2228 found = resolve_collision_directly(c, key, &znode, &n,
2229 old_lnum, old_offs);
2230 dbg_tnc("rc returned %d, znode %p, n %d, LEB %d:%d",
2231 found, znode, n, old_lnum, old_offs);
2232 if (found < 0) {
2233 err = found;
2234 goto out_unlock;
2235 }
2236
2237 if (found) {
2238 /* Ensure the znode is dirtied */
2239 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2240 znode = dirty_cow_bottom_up(c, znode);
2241 if (IS_ERR(znode)) {
2242 err = PTR_ERR(znode);
2243 goto out_unlock;
2244 }
2245 }
2246 zbr = &znode->zbranch[n];
2247 lnc_free(zbr);
2248 err = ubifs_add_dirt(c, zbr->lnum,
2249 zbr->len);
2250 if (err)
2251 goto out_unlock;
2252 zbr->lnum = lnum;
2253 zbr->offs = offs;
2254 zbr->len = len;
2255 }
2256 }
2257 }
2258
2259 if (!found)
2260 err = ubifs_add_dirt(c, lnum, len);
2261
2262 if (!err)
2263 err = dbg_check_tnc(c, 0);
2264
2265out_unlock:
2266 mutex_unlock(&c->tnc_mutex);
2267 return err;
2268}
2269
2270/**
2271 * ubifs_tnc_add_nm - add a "hashed" node to TNC.
2272 * @c: UBIFS file-system description object
2273 * @key: key to add
2274 * @lnum: LEB number of node
2275 * @offs: node offset
2276 * @len: node length
2277 * @nm: node name
2278 *
2279 * This is the same as 'ubifs_tnc_add()' but it should be used with keys which
2280 * may have collisions, like directory entry keys.
2281 */
2282int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
2283 int lnum, int offs, int len, const struct qstr *nm)
2284{
2285 int found, n, err = 0;
2286 struct ubifs_znode *znode;
2287
2288 mutex_lock(&c->tnc_mutex);
2289 dbg_tnck(key, "LEB %d:%d, name '%.*s', key ",
2290 lnum, offs, nm->len, nm->name);
2291 found = lookup_level0_dirty(c, key, &znode, &n);
2292 if (found < 0) {
2293 err = found;
2294 goto out_unlock;
2295 }
2296
2297 if (found == 1) {
2298 if (c->replaying)
2299 found = fallible_resolve_collision(c, key, &znode, &n,
2300 nm, 1);
2301 else
2302 found = resolve_collision(c, key, &znode, &n, nm);
2303 dbg_tnc("rc returned %d, znode %p, n %d", found, znode, n);
2304 if (found < 0) {
2305 err = found;
2306 goto out_unlock;
2307 }
2308
2309 /* Ensure the znode is dirtied */
2310 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2311 znode = dirty_cow_bottom_up(c, znode);
2312 if (IS_ERR(znode)) {
2313 err = PTR_ERR(znode);
2314 goto out_unlock;
2315 }
2316 }
2317
2318 if (found == 1) {
2319 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2320
2321 lnc_free(zbr);
2322 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2323 zbr->lnum = lnum;
2324 zbr->offs = offs;
2325 zbr->len = len;
2326 goto out_unlock;
2327 }
2328 }
2329
2330 if (!found) {
2331 struct ubifs_zbranch zbr;
2332
2333 zbr.znode = NULL;
2334 zbr.lnum = lnum;
2335 zbr.offs = offs;
2336 zbr.len = len;
2337 key_copy(c, key, &zbr.key);
2338 err = tnc_insert(c, znode, &zbr, n + 1);
2339 if (err)
2340 goto out_unlock;
2341 if (c->replaying) {
2342 /*
2343 * We did not find it in the index so there may be a
2344 * dangling branch still in the index. So we remove it
2345 * by passing 'ubifs_tnc_remove_nm()' the same key but
2346 * an unmatchable name.
2347 */
2348 struct qstr noname = { .name = "" };
2349
2350 err = dbg_check_tnc(c, 0);
2351 mutex_unlock(&c->tnc_mutex);
2352 if (err)
2353 return err;
2354 return ubifs_tnc_remove_nm(c, key, &noname);
2355 }
2356 }
2357
2358out_unlock:
2359 if (!err)
2360 err = dbg_check_tnc(c, 0);
2361 mutex_unlock(&c->tnc_mutex);
2362 return err;
2363}
2364
2365/**
2366 * tnc_delete - delete a znode form TNC.
2367 * @c: UBIFS file-system description object
2368 * @znode: znode to delete from
2369 * @n: zbranch slot number to delete
2370 *
2371 * This function deletes a leaf node from @n-th slot of @znode. Returns zero in
2372 * case of success and a negative error code in case of failure.
2373 */
2374static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n)
2375{
2376 struct ubifs_zbranch *zbr;
2377 struct ubifs_znode *zp;
2378 int i, err;
2379
2380 /* Delete without merge for now */
2381 ubifs_assert(znode->level == 0);
2382 ubifs_assert(n >= 0 && n < c->fanout);
2383 dbg_tnck(&znode->zbranch[n].key, "deleting key ");
2384
2385 zbr = &znode->zbranch[n];
2386 lnc_free(zbr);
2387
2388 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2389 if (err) {
2390 ubifs_dump_znode(c, znode);
2391 return err;
2392 }
2393
2394 /* We do not "gap" zbranch slots */
2395 for (i = n; i < znode->child_cnt - 1; i++)
2396 znode->zbranch[i] = znode->zbranch[i + 1];
2397 znode->child_cnt -= 1;
2398
2399 if (znode->child_cnt > 0)
2400 return 0;
2401
2402 /*
2403 * This was the last zbranch, we have to delete this znode from the
2404 * parent.
2405 */
2406
2407 do {
2408 ubifs_assert(!ubifs_zn_obsolete(znode));
2409 ubifs_assert(ubifs_zn_dirty(znode));
2410
2411 zp = znode->parent;
2412 n = znode->iip;
2413
2414 atomic_long_dec(&c->dirty_zn_cnt);
2415
2416 err = insert_old_idx_znode(c, znode);
2417 if (err)
2418 return err;
2419
2420 if (znode->cnext) {
2421 __set_bit(OBSOLETE_ZNODE, &znode->flags);
2422 atomic_long_inc(&c->clean_zn_cnt);
2423 atomic_long_inc(&ubifs_clean_zn_cnt);
2424 } else
2425 kfree(znode);
2426 znode = zp;
2427 } while (znode->child_cnt == 1); /* while removing last child */
2428
2429 /* Remove from znode, entry n - 1 */
2430 znode->child_cnt -= 1;
2431 ubifs_assert(znode->level != 0);
2432 for (i = n; i < znode->child_cnt; i++) {
2433 znode->zbranch[i] = znode->zbranch[i + 1];
2434 if (znode->zbranch[i].znode)
2435 znode->zbranch[i].znode->iip = i;
2436 }
2437
2438 /*
2439 * If this is the root and it has only 1 child then
2440 * collapse the tree.
2441 */
2442 if (!znode->parent) {
2443 while (znode->child_cnt == 1 && znode->level != 0) {
2444 zp = znode;
2445 zbr = &znode->zbranch[0];
2446 znode = get_znode(c, znode, 0);
2447 if (IS_ERR(znode))
2448 return PTR_ERR(znode);
2449 znode = dirty_cow_znode(c, zbr);
2450 if (IS_ERR(znode))
2451 return PTR_ERR(znode);
2452 znode->parent = NULL;
2453 znode->iip = 0;
2454 if (c->zroot.len) {
2455 err = insert_old_idx(c, c->zroot.lnum,
2456 c->zroot.offs);
2457 if (err)
2458 return err;
2459 }
2460 c->zroot.lnum = zbr->lnum;
2461 c->zroot.offs = zbr->offs;
2462 c->zroot.len = zbr->len;
2463 c->zroot.znode = znode;
2464 ubifs_assert(!ubifs_zn_obsolete(zp));
2465 ubifs_assert(ubifs_zn_dirty(zp));
2466 atomic_long_dec(&c->dirty_zn_cnt);
2467
2468 if (zp->cnext) {
2469 __set_bit(OBSOLETE_ZNODE, &zp->flags);
2470 atomic_long_inc(&c->clean_zn_cnt);
2471 atomic_long_inc(&ubifs_clean_zn_cnt);
2472 } else
2473 kfree(zp);
2474 }
2475 }
2476
2477 return 0;
2478}
2479
2480/**
2481 * ubifs_tnc_remove - remove an index entry of a node.
2482 * @c: UBIFS file-system description object
2483 * @key: key of node
2484 *
2485 * Returns %0 on success or negative error code on failure.
2486 */
2487int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key)
2488{
2489 int found, n, err = 0;
2490 struct ubifs_znode *znode;
2491
2492 mutex_lock(&c->tnc_mutex);
2493 dbg_tnck(key, "key ");
2494 found = lookup_level0_dirty(c, key, &znode, &n);
2495 if (found < 0) {
2496 err = found;
2497 goto out_unlock;
2498 }
2499 if (found == 1)
2500 err = tnc_delete(c, znode, n);
2501 if (!err)
2502 err = dbg_check_tnc(c, 0);
2503
2504out_unlock:
2505 mutex_unlock(&c->tnc_mutex);
2506 return err;
2507}
2508
2509/**
2510 * ubifs_tnc_remove_nm - remove an index entry for a "hashed" node.
2511 * @c: UBIFS file-system description object
2512 * @key: key of node
2513 * @nm: directory entry name
2514 *
2515 * Returns %0 on success or negative error code on failure.
2516 */
2517int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
2518 const struct qstr *nm)
2519{
2520 int n, err;
2521 struct ubifs_znode *znode;
2522
2523 mutex_lock(&c->tnc_mutex);
2524 dbg_tnck(key, "%.*s, key ", nm->len, nm->name);
2525 err = lookup_level0_dirty(c, key, &znode, &n);
2526 if (err < 0)
2527 goto out_unlock;
2528
2529 if (err) {
2530 if (c->replaying)
2531 err = fallible_resolve_collision(c, key, &znode, &n,
2532 nm, 0);
2533 else
2534 err = resolve_collision(c, key, &znode, &n, nm);
2535 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
2536 if (err < 0)
2537 goto out_unlock;
2538 if (err) {
2539 /* Ensure the znode is dirtied */
2540 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2541 znode = dirty_cow_bottom_up(c, znode);
2542 if (IS_ERR(znode)) {
2543 err = PTR_ERR(znode);
2544 goto out_unlock;
2545 }
2546 }
2547 err = tnc_delete(c, znode, n);
2548 }
2549 }
2550
2551out_unlock:
2552 if (!err)
2553 err = dbg_check_tnc(c, 0);
2554 mutex_unlock(&c->tnc_mutex);
2555 return err;
2556}
2557
2558/**
2559 * key_in_range - determine if a key falls within a range of keys.
2560 * @c: UBIFS file-system description object
2561 * @key: key to check
2562 * @from_key: lowest key in range
2563 * @to_key: highest key in range
2564 *
2565 * This function returns %1 if the key is in range and %0 otherwise.
2566 */
2567static int key_in_range(struct ubifs_info *c, union ubifs_key *key,
2568 union ubifs_key *from_key, union ubifs_key *to_key)
2569{
2570 if (keys_cmp(c, key, from_key) < 0)
2571 return 0;
2572 if (keys_cmp(c, key, to_key) > 0)
2573 return 0;
2574 return 1;
2575}
2576
2577/**
2578 * ubifs_tnc_remove_range - remove index entries in range.
2579 * @c: UBIFS file-system description object
2580 * @from_key: lowest key to remove
2581 * @to_key: highest key to remove
2582 *
2583 * This function removes index entries starting at @from_key and ending at
2584 * @to_key. This function returns zero in case of success and a negative error
2585 * code in case of failure.
2586 */
2587int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key,
2588 union ubifs_key *to_key)
2589{
2590 int i, n, k, err = 0;
2591 struct ubifs_znode *znode;
2592 union ubifs_key *key;
2593
2594 mutex_lock(&c->tnc_mutex);
2595 while (1) {
2596 /* Find first level 0 znode that contains keys to remove */
2597 err = ubifs_lookup_level0(c, from_key, &znode, &n);
2598 if (err < 0)
2599 goto out_unlock;
2600
2601 if (err)
2602 key = from_key;
2603 else {
2604 err = tnc_next(c, &znode, &n);
2605 if (err == -ENOENT) {
2606 err = 0;
2607 goto out_unlock;
2608 }
2609 if (err < 0)
2610 goto out_unlock;
2611 key = &znode->zbranch[n].key;
2612 if (!key_in_range(c, key, from_key, to_key)) {
2613 err = 0;
2614 goto out_unlock;
2615 }
2616 }
2617
2618 /* Ensure the znode is dirtied */
2619 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2620 znode = dirty_cow_bottom_up(c, znode);
2621 if (IS_ERR(znode)) {
2622 err = PTR_ERR(znode);
2623 goto out_unlock;
2624 }
2625 }
2626
2627 /* Remove all keys in range except the first */
2628 for (i = n + 1, k = 0; i < znode->child_cnt; i++, k++) {
2629 key = &znode->zbranch[i].key;
2630 if (!key_in_range(c, key, from_key, to_key))
2631 break;
2632 lnc_free(&znode->zbranch[i]);
2633 err = ubifs_add_dirt(c, znode->zbranch[i].lnum,
2634 znode->zbranch[i].len);
2635 if (err) {
2636 ubifs_dump_znode(c, znode);
2637 goto out_unlock;
2638 }
2639 dbg_tnck(key, "removing key ");
2640 }
2641 if (k) {
2642 for (i = n + 1 + k; i < znode->child_cnt; i++)
2643 znode->zbranch[i - k] = znode->zbranch[i];
2644 znode->child_cnt -= k;
2645 }
2646
2647 /* Now delete the first */
2648 err = tnc_delete(c, znode, n);
2649 if (err)
2650 goto out_unlock;
2651 }
2652
2653out_unlock:
2654 if (!err)
2655 err = dbg_check_tnc(c, 0);
2656 mutex_unlock(&c->tnc_mutex);
2657 return err;
2658}
2659
2660/**
2661 * ubifs_tnc_remove_ino - remove an inode from TNC.
2662 * @c: UBIFS file-system description object
2663 * @inum: inode number to remove
2664 *
2665 * This function remove inode @inum and all the extended attributes associated
2666 * with the anode from TNC and returns zero in case of success or a negative
2667 * error code in case of failure.
2668 */
2669int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum)
2670{
2671 union ubifs_key key1, key2;
2672 struct ubifs_dent_node *xent, *pxent = NULL;
2673 struct qstr nm = { .name = NULL };
2674
2675 dbg_tnc("ino %lu", (unsigned long)inum);
2676
2677 /*
2678 * Walk all extended attribute entries and remove them together with
2679 * corresponding extended attribute inodes.
2680 */
2681 lowest_xent_key(c, &key1, inum);
2682 while (1) {
2683 ino_t xattr_inum;
2684 int err;
2685
2686 xent = ubifs_tnc_next_ent(c, &key1, &nm);
2687 if (IS_ERR(xent)) {
2688 err = PTR_ERR(xent);
2689 if (err == -ENOENT)
2690 break;
2691 return err;
2692 }
2693
2694 xattr_inum = le64_to_cpu(xent->inum);
2695 dbg_tnc("xent '%s', ino %lu", xent->name,
2696 (unsigned long)xattr_inum);
2697
2698 nm.name = xent->name;
2699 nm.len = le16_to_cpu(xent->nlen);
2700 err = ubifs_tnc_remove_nm(c, &key1, &nm);
2701 if (err) {
2702 kfree(xent);
2703 return err;
2704 }
2705
2706 lowest_ino_key(c, &key1, xattr_inum);
2707 highest_ino_key(c, &key2, xattr_inum);
2708 err = ubifs_tnc_remove_range(c, &key1, &key2);
2709 if (err) {
2710 kfree(xent);
2711 return err;
2712 }
2713
2714 kfree(pxent);
2715 pxent = xent;
2716 key_read(c, &xent->key, &key1);
2717 }
2718
2719 kfree(pxent);
2720 lowest_ino_key(c, &key1, inum);
2721 highest_ino_key(c, &key2, inum);
2722
2723 return ubifs_tnc_remove_range(c, &key1, &key2);
2724}
2725
2726/**
2727 * ubifs_tnc_next_ent - walk directory or extended attribute entries.
2728 * @c: UBIFS file-system description object
2729 * @key: key of last entry
2730 * @nm: name of last entry found or %NULL
2731 *
2732 * This function finds and reads the next directory or extended attribute entry
2733 * after the given key (@key) if there is one. @nm is used to resolve
2734 * collisions.
2735 *
2736 * If the name of the current entry is not known and only the key is known,
2737 * @nm->name has to be %NULL. In this case the semantics of this function is a
2738 * little bit different and it returns the entry corresponding to this key, not
2739 * the next one. If the key was not found, the closest "right" entry is
2740 * returned.
2741 *
2742 * If the fist entry has to be found, @key has to contain the lowest possible
2743 * key value for this inode and @name has to be %NULL.
2744 *
2745 * This function returns the found directory or extended attribute entry node
2746 * in case of success, %-ENOENT is returned if no entry was found, and a
2747 * negative error code is returned in case of failure.
2748 */
2749struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c,
2750 union ubifs_key *key,
2751 const struct qstr *nm)
2752{
2753 int n, err, type = key_type(c, key);
2754 struct ubifs_znode *znode;
2755 struct ubifs_dent_node *dent;
2756 struct ubifs_zbranch *zbr;
2757 union ubifs_key *dkey;
2758
2759 dbg_tnck(key, "%s ", nm->name ? (char *)nm->name : "(lowest)");
2760 ubifs_assert(is_hash_key(c, key));
2761
2762 mutex_lock(&c->tnc_mutex);
2763 err = ubifs_lookup_level0(c, key, &znode, &n);
2764 if (unlikely(err < 0))
2765 goto out_unlock;
2766
2767 if (nm->name) {
2768 if (err) {
2769 /* Handle collisions */
2770 err = resolve_collision(c, key, &znode, &n, nm);
2771 dbg_tnc("rc returned %d, znode %p, n %d",
2772 err, znode, n);
2773 if (unlikely(err < 0))
2774 goto out_unlock;
2775 }
2776
2777 /* Now find next entry */
2778 err = tnc_next(c, &znode, &n);
2779 if (unlikely(err))
2780 goto out_unlock;
2781 } else {
2782 /*
2783 * The full name of the entry was not given, in which case the
2784 * behavior of this function is a little different and it
2785 * returns current entry, not the next one.
2786 */
2787 if (!err) {
2788 /*
2789 * However, the given key does not exist in the TNC
2790 * tree and @znode/@n variables contain the closest
2791 * "preceding" element. Switch to the next one.
2792 */
2793 err = tnc_next(c, &znode, &n);
2794 if (err)
2795 goto out_unlock;
2796 }
2797 }
2798
2799 zbr = &znode->zbranch[n];
2800 dent = kmalloc(zbr->len, GFP_NOFS);
2801 if (unlikely(!dent)) {
2802 err = -ENOMEM;
2803 goto out_unlock;
2804 }
2805
2806 /*
2807 * The above 'tnc_next()' call could lead us to the next inode, check
2808 * this.
2809 */
2810 dkey = &zbr->key;
2811 if (key_inum(c, dkey) != key_inum(c, key) ||
2812 key_type(c, dkey) != type) {
2813 err = -ENOENT;
2814 goto out_free;
2815 }
2816
2817 err = tnc_read_node_nm(c, zbr, dent);
2818 if (unlikely(err))
2819 goto out_free;
2820
2821 mutex_unlock(&c->tnc_mutex);
2822 return dent;
2823
2824out_free:
2825 kfree(dent);
2826out_unlock:
2827 mutex_unlock(&c->tnc_mutex);
2828 return ERR_PTR(err);
2829}
2830
2831/**
2832 * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit.
2833 * @c: UBIFS file-system description object
2834 *
2835 * Destroy left-over obsolete znodes from a failed commit.
2836 */
2837static void tnc_destroy_cnext(struct ubifs_info *c)
2838{
2839 struct ubifs_znode *cnext;
2840
2841 if (!c->cnext)
2842 return;
2843 ubifs_assert(c->cmt_state == COMMIT_BROKEN);
2844 cnext = c->cnext;
2845 do {
2846 struct ubifs_znode *znode = cnext;
2847
2848 cnext = cnext->cnext;
2849 if (ubifs_zn_obsolete(znode))
2850 kfree(znode);
2851 } while (cnext && cnext != c->cnext);
2852}
2853
2854/**
2855 * ubifs_tnc_close - close TNC subsystem and free all related resources.
2856 * @c: UBIFS file-system description object
2857 */
2858void ubifs_tnc_close(struct ubifs_info *c)
2859{
2860 tnc_destroy_cnext(c);
2861 if (c->zroot.znode) {
2862 long n;
2863
2864 ubifs_destroy_tnc_subtree(c->zroot.znode);
2865 n = atomic_long_read(&c->clean_zn_cnt);
2866 atomic_long_sub(n, &ubifs_clean_zn_cnt);
2867 }
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
2956 * nodes it traverses to TNC. This function is called for indexing nodes which
2957 * 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
2978 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
2979
2980 /*
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}
3261
3262/**
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;
3283 if (!dbg_is_chk_gen(c))
3284 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) {
3296 err = -EINVAL;
3297 key = &from_key;
3298 goto out_dump;
3299 }
3300
3301 err = tnc_next(c, &znode, &n);
3302 if (err == -ENOENT) {
3303 err = 0;
3304 goto out_unlock;
3305 }
3306 if (err < 0)
3307 goto out_unlock;
3308
3309 ubifs_assert(err == 0);
3310 key = &znode->zbranch[n].key;
3311 if (!key_in_range(c, key, &from_key, &to_key))
3312 goto out_unlock;
3313
3314out_dump:
3315 block = key_block(c, key);
3316 ubifs_err("inode %lu has size %lld, but there are data at offset %lld",
3317 (unsigned long)inode->i_ino, size,
3318 ((loff_t)block) << UBIFS_BLOCK_SHIFT);
3319 mutex_unlock(&c->tnc_mutex);
3320 ubifs_dump_inode(c, inode);
3321 dump_stack();
3322 return -EINVAL;
3323
3324out_unlock:
3325 mutex_unlock(&c->tnc_mutex);
3326 return err;
3327}