Merge branches 'core-fixes-for-linus' and 'irq-fixes-for-linus' of git://git.kernel...
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / ubifs / tnc.c
blob8119b1fd8d94b9be59320e1c31e1d5b41d050dc1
1 /*
2 * This file is part of UBIFS.
4 * Copyright (C) 2006-2008 Nokia Corporation.
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.
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.
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
19 * Authors: Adrian Hunter
20 * Artem Bityutskiy (Битюцкий Артём)
24 * This file implements TNC (Tree Node Cache) which caches indexing nodes of
25 * the UBIFS B-tree.
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.
33 #include <linux/crc32.h>
34 #include <linux/slab.h>
35 #include "ubifs.h"
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
45 * These constants were introduce to improve readability.
47 enum {
48 NAME_LESS = 0,
49 NAME_MATCHES = 1,
50 NAME_GREATER = 2,
51 NOT_ON_MEDIA = 3,
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
60 * Returns %0 on success, and a negative error code on failure.
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).
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.
77 static int insert_old_idx(struct ubifs_info *c, int lnum, int offs)
79 struct ubifs_old_idx *old_idx, *o;
80 struct rb_node **p, *parent = NULL;
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;
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;
106 rb_link_node(&old_idx->rb, parent, p);
107 rb_insert_color(&old_idx->rb, &c->old_idx);
108 return 0;
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
116 * Returns %0 on success, and a negative error code on failure.
118 int insert_old_idx_znode(struct ubifs_info *c, struct ubifs_znode *znode)
120 if (znode->parent) {
121 struct ubifs_zbranch *zbr;
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;
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
138 * Returns %0 on success, and a negative error code on failure.
140 static int ins_clr_old_idx_znode(struct ubifs_info *c,
141 struct ubifs_znode *znode)
143 int err;
145 if (znode->parent) {
146 struct ubifs_zbranch *zbr;
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;
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;
166 return 0;
170 * destroy_old_idx - destroy the old_idx RB-tree.
171 * @c: UBIFS file-system description object
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.
179 void destroy_old_idx(struct ubifs_info *c)
181 struct rb_node *this = c->old_idx.rb_node;
182 struct ubifs_old_idx *old_idx;
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;
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;
200 kfree(old_idx);
202 c->old_idx = RB_ROOT;
206 * copy_znode - copy a dirty znode.
207 * @c: UBIFS file-system description object
208 * @znode: znode to copy
210 * A dirty znode being committed may not be changed, so it is copied.
212 static struct ubifs_znode *copy_znode(struct ubifs_info *c,
213 struct ubifs_znode *znode)
215 struct ubifs_znode *zn;
217 zn = kmalloc(c->max_znode_sz, GFP_NOFS);
218 if (unlikely(!zn))
219 return ERR_PTR(-ENOMEM);
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);
226 ubifs_assert(!test_bit(OBSOLETE_ZNODE, &znode->flags));
227 __set_bit(OBSOLETE_ZNODE, &znode->flags);
229 if (znode->level != 0) {
230 int i;
231 const int n = zn->child_cnt;
233 /* The children now have new parent */
234 for (i = 0; i < n; i++) {
235 struct ubifs_zbranch *zbr = &zn->zbranch[i];
237 if (zbr->znode)
238 zbr->znode->parent = zn;
242 atomic_long_inc(&c->dirty_zn_cnt);
243 return zn;
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
252 * This function updates lprops dirty space and the new size of the index.
254 static int add_idx_dirt(struct ubifs_info *c, int lnum, int dirt)
256 c->calc_idx_sz -= ALIGN(dirt, 8);
257 return ubifs_add_dirt(c, lnum, dirt);
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
265 * Returns dirtied znode on success or negative error code on failure.
267 static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c,
268 struct ubifs_zbranch *zbr)
270 struct ubifs_znode *znode = zbr->znode;
271 struct ubifs_znode *zn;
272 int err;
274 if (!test_bit(COW_ZNODE, &znode->flags)) {
275 /* znode is not being committed */
276 if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) {
277 atomic_long_inc(&c->dirty_zn_cnt);
278 atomic_long_dec(&c->clean_zn_cnt);
279 atomic_long_dec(&ubifs_clean_zn_cnt);
280 err = add_idx_dirt(c, zbr->lnum, zbr->len);
281 if (unlikely(err))
282 return ERR_PTR(err);
284 return znode;
287 zn = copy_znode(c, znode);
288 if (IS_ERR(zn))
289 return zn;
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;
299 zbr->znode = zn;
300 zbr->lnum = 0;
301 zbr->offs = 0;
302 zbr->len = 0;
304 if (unlikely(err))
305 return ERR_PTR(err);
306 return zn;
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
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.
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.
329 static int lnc_add(struct ubifs_info *c, struct ubifs_zbranch *zbr,
330 const void *node)
332 int err;
333 void *lnc_node;
334 const struct ubifs_dent_node *dent = node;
336 ubifs_assert(!zbr->leaf);
337 ubifs_assert(zbr->len != 0);
338 ubifs_assert(is_hash_key(c, &zbr->key));
340 err = ubifs_validate_entry(c, dent);
341 if (err) {
342 dbg_dump_stack();
343 dbg_dump_node(c, dent);
344 return err;
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;
352 memcpy(lnc_node, node, zbr->len);
353 zbr->leaf = lnc_node;
354 return 0;
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
363 * This function is similar to 'lnc_add()', but it does not create a copy of
364 * @node but inserts @node to TNC directly.
366 static int lnc_add_directly(struct ubifs_info *c, struct ubifs_zbranch *zbr,
367 void *node)
369 int err;
371 ubifs_assert(!zbr->leaf);
372 ubifs_assert(zbr->len != 0);
374 err = ubifs_validate_entry(c, node);
375 if (err) {
376 dbg_dump_stack();
377 dbg_dump_node(c, node);
378 return err;
381 zbr->leaf = node;
382 return 0;
386 * lnc_free - remove a leaf node from the leaf node cache.
387 * @zbr: zbranch of leaf node
388 * @node: leaf node
390 static void lnc_free(struct ubifs_zbranch *zbr)
392 if (!zbr->leaf)
393 return;
394 kfree(zbr->leaf);
395 zbr->leaf = NULL;
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
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.
409 static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr,
410 void *node)
412 int err;
414 ubifs_assert(is_hash_key(c, &zbr->key));
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;
423 err = ubifs_tnc_read_node(c, zbr, node);
424 if (err)
425 return err;
427 /* Add the node to the leaf node cache */
428 err = lnc_add(c, zbr, node);
429 return err;
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
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.
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.
456 static int try_read_node(const struct ubifs_info *c, void *buf, int type,
457 int len, int lnum, int offs)
459 int err, node_len;
460 struct ubifs_ch *ch = buf;
461 uint32_t crc, node_crc;
463 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
465 err = ubi_read(c->ubi, lnum, buf, offs, len);
466 if (err) {
467 ubifs_err("cannot read node type %d from LEB %d:%d, error %d",
468 type, lnum, offs, err);
469 return err;
472 if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC)
473 return 0;
475 if (ch->node_type != type)
476 return 0;
478 node_len = le32_to_cpu(ch->len);
479 if (node_len != len)
480 return 0;
482 if (type == UBIFS_DATA_NODE && c->no_chk_data_crc && !c->mounting &&
483 !c->remounting_rw)
484 return 1;
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;
491 return 1;
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
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.
504 static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
505 struct ubifs_zbranch *zbr, void *node)
507 int ret;
509 dbg_tnc("LEB %d:%d, key %s", zbr->lnum, zbr->offs, DBGKEY(key));
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;
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;
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;
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
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.
539 static int matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr,
540 const struct qstr *nm)
542 struct ubifs_dent_node *dent;
543 int nlen, err;
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;
551 err = ubifs_tnc_read_node(c, zbr, dent);
552 if (err)
553 goto out_free;
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;
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;
576 out_free:
577 kfree(dent);
578 return err;
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
587 * This function returns the znode or a negative error code.
589 static struct ubifs_znode *get_znode(struct ubifs_info *c,
590 struct ubifs_znode *znode, int n)
592 struct ubifs_zbranch *zbr;
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;
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
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.
611 static int tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
613 struct ubifs_znode *znode = *zn;
614 int nn = *n;
616 nn += 1;
617 if (nn < znode->child_cnt) {
618 *n = nn;
619 return 0;
621 while (1) {
622 struct ubifs_znode *zp;
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);
638 nn = 0;
639 break;
642 *zn = znode;
643 *n = nn;
644 return 0;
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
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.
656 static int tnc_prev(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
658 struct ubifs_znode *znode = *zn;
659 int nn = *n;
661 if (nn > 0) {
662 *n = nn - 1;
663 return 0;
665 while (1) {
666 struct ubifs_znode *zp;
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);
683 nn = znode->child_cnt - 1;
684 break;
687 *zn = znode;
688 *n = nn;
689 return 0;
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
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.
708 static int resolve_collision(struct ubifs_info *c, const union ubifs_key *key,
709 struct ubifs_znode **zn, int *n,
710 const struct qstr *nm)
712 int err;
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;
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;
729 if (err < 0)
730 return err;
731 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
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.
739 * znode zp
740 * ----------------------
741 * level 1 | Key0 | Key1 |
742 * -----------------------
743 * | |
744 * znode za | | znode zb
745 * ------------ ------------
746 * level 0 | Key0 | | Key2 |
747 * ------------ ------------
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.
757 * Note, this problem is not relevant for the
758 * case when we go right, because
759 * 'tnc_insert()' would correct the parent key.
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;
770 ubifs_assert(*n == 0);
771 *n = -1;
773 return 0;
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);
784 } else {
785 int nn = *n;
786 struct ubifs_znode *znode = *zn;
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);
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
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.
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.
826 static int fallible_matches_name(struct ubifs_info *c,
827 struct ubifs_zbranch *zbr,
828 const struct qstr *nm)
830 struct ubifs_dent_node *dent;
831 int nlen, err;
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;
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;
847 ubifs_assert(err == 1);
849 err = lnc_add_directly(c, zbr, dent);
850 if (err)
851 goto out_free;
852 } else
853 dent = zbr->leaf;
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;
869 out_free:
870 kfree(dent);
871 return err;
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
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.
896 static int fallible_resolve_collision(struct ubifs_info *c,
897 const union ubifs_key *key,
898 struct ubifs_znode **zn, int *n,
899 const struct qstr *nm, int adding)
901 struct ubifs_znode *o_znode = NULL, *znode = *zn;
902 int uninitialized_var(o_n), err, cmp, unsure = 0, nn = *n;
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;
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.
917 unsure = 1;
918 } else if (!adding)
919 unsure = 1; /* Remove a dangling branch wherever it is */
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;
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;
943 ubifs_assert(*n == 0);
944 *n = -1;
946 break;
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;
958 if (!adding)
959 continue;
960 if (err == NAME_LESS)
961 break;
962 else
963 unsure = 0;
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;
995 /* Never match a dangling branch when adding */
996 if (adding || !o_znode)
997 return 0;
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;
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
1013 * This function returns %1 if @lnum:@offs matches, and %0 otherwise.
1015 static int matches_position(struct ubifs_zbranch *zbr, int lnum, int offs)
1017 if (zbr->lnum == lnum && zbr->offs == offs)
1018 return 1;
1019 else
1020 return 0;
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
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.
1040 static int resolve_collision_directly(struct ubifs_info *c,
1041 const union ubifs_key *key,
1042 struct ubifs_znode **zn, int *n,
1043 int lnum, int offs)
1045 struct ubifs_znode *znode;
1046 int nn, err;
1048 znode = *zn;
1049 nn = *n;
1050 if (matches_position(&znode->zbranch[nn], lnum, offs))
1051 return 1;
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;
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;
1088 * dirty_cow_bottom_up - dirty a znode and its ancestors.
1089 * @c: UBIFS file-system description object
1090 * @znode: znode to dirty
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.
1097 static struct ubifs_znode *dirty_cow_bottom_up(struct ubifs_info *c,
1098 struct ubifs_znode *znode)
1100 struct ubifs_znode *zp;
1101 int *path = c->bottom_up_buf, p = 0;
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;
1113 if (c->zroot.znode->level) {
1114 /* Go up until parent is dirty */
1115 while (1) {
1116 int n;
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;
1130 /* Come back down, dirtying as we go */
1131 while (1) {
1132 struct ubifs_zbranch *zbr;
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);
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;
1151 return znode;
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
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.
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.
1176 int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
1177 struct ubifs_znode **zn, int *n)
1179 int err, exact;
1180 struct ubifs_znode *znode;
1181 unsigned long time = get_seconds();
1183 dbg_tnc("search key %s", DBGKEY(key));
1184 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
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);
1193 znode->time = time;
1195 while (1) {
1196 struct ubifs_zbranch *zbr;
1198 exact = ubifs_search_zbranch(c, znode, key, n);
1200 if (znode->level == 0)
1201 break;
1203 if (*n < 0)
1204 *n = 0;
1205 zbr = &znode->zbranch[*n];
1207 if (zbr->znode) {
1208 znode->time = time;
1209 znode = zbr->znode;
1210 continue;
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);
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;
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:
1230 * | 3 | 5 |
1231 * / \
1232 * | 3 | 5 | | 6 | 7 | (x)
1234 * Or more a complex example:
1236 * | 1 | 5 |
1237 * / \
1238 * | 1 | 3 | | 5 | 8 |
1239 * \ /
1240 * | 5 | 5 | | 6 | 7 | (x)
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.
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 |
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.
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;
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;
1282 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1283 *zn = znode;
1284 return 1;
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
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.
1305 * Additionally all znodes in the path from the root to the located zero-level
1306 * znode are marked as dirty.
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.
1312 static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key,
1313 struct ubifs_znode **zn, int *n)
1315 int err, exact;
1316 struct ubifs_znode *znode;
1317 unsigned long time = get_seconds();
1319 dbg_tnc("search and dirty key %s", DBGKEY(key));
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);
1328 znode = dirty_cow_znode(c, &c->zroot);
1329 if (IS_ERR(znode))
1330 return PTR_ERR(znode);
1332 znode->time = time;
1334 while (1) {
1335 struct ubifs_zbranch *zbr;
1337 exact = ubifs_search_zbranch(c, znode, key, n);
1339 if (znode->level == 0)
1340 break;
1342 if (*n < 0)
1343 *n = 0;
1344 zbr = &znode->zbranch[*n];
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;
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);
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;
1370 * See huge comment at 'lookup_level0_dirty()' what is the rest of the
1371 * code.
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;
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;
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);
1393 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1394 *zn = znode;
1395 return 1;
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
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.
1408 static int maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1)
1410 int gc_seq2, gced_lnum;
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;
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.
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;
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
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.
1447 int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key,
1448 void *node, int *lnum, int *offs)
1450 int found, n, err, safely = 0, gc_seq1;
1451 struct ubifs_znode *znode;
1452 struct ubifs_zbranch zbr, *zt;
1454 again:
1455 mutex_lock(&c->tnc_mutex);
1456 found = ubifs_lookup_level0(c, key, &znode, &n);
1457 if (!found) {
1458 err = -ENOENT;
1459 goto out;
1460 } else if (found < 0) {
1461 err = found;
1462 goto out;
1464 zt = &znode->zbranch[n];
1465 if (lnum) {
1466 *lnum = zt->lnum;
1467 *offs = zt->offs;
1469 if (is_hash_key(c, key)) {
1471 * In this case the leaf node cache gets used, so we pass the
1472 * address of the zbranch and keep the mutex locked
1474 err = tnc_read_node_nm(c, zt, node);
1475 goto out;
1477 if (safely) {
1478 err = ubifs_tnc_read_node(c, zt, node);
1479 goto out;
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);
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;
1492 err = fallible_read_node(c, key, &zbr, node);
1493 if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) {
1495 * The node may have been GC'ed out from under us so try again
1496 * while keeping the TNC mutex locked.
1498 safely = 1;
1499 goto again;
1501 return 0;
1503 out:
1504 mutex_unlock(&c->tnc_mutex);
1505 return err;
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
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.
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.
1521 int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)
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;
1528 bu->cnt = 0;
1529 bu->blk_cnt = 0;
1530 bu->eof = 0;
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;
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);
1551 while (1) {
1552 struct ubifs_zbranch *zbr;
1553 union ubifs_key *key;
1554 unsigned int next_block;
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;
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;
1577 } else {
1579 * The data nodes must be in consecutive positions in
1580 * the same LEB.
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;
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;
1605 out:
1606 if (err == -ENOENT) {
1607 bu->eof = 1;
1608 err = 0;
1610 bu->gc_seq = c->gc_seq;
1611 mutex_unlock(&c->tnc_mutex);
1612 if (err)
1613 return err;
1615 * An enormous hole could cause bulk-read to encompass too many
1616 * page cache pages, so limit the number here.
1618 if (bu->blk_cnt > UBIFS_MAX_BULK_READ)
1619 bu->blk_cnt = UBIFS_MAX_BULK_READ;
1621 * Ensure that bulk-read covers a whole number of page cache
1622 * pages.
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;
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;
1640 return 0;
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
1651 * This functions returns %0 on success or a negative error code on failure.
1653 static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum,
1654 int offs)
1656 const struct ubifs_info *c = wbuf->c;
1657 int rlen, overlap;
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);
1664 spin_lock(&wbuf->lock);
1665 overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
1666 if (!overlap) {
1667 /* We may safely unlock the write-buffer and read the data */
1668 spin_unlock(&wbuf->lock);
1669 return ubi_read(c->ubi, lnum, buf, offs, len);
1672 /* Don't read under wbuf */
1673 rlen = wbuf->offs - offs;
1674 if (rlen < 0)
1675 rlen = 0;
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);
1681 if (rlen > 0)
1682 /* Read everything that goes before write-buffer */
1683 return ubi_read(c->ubi, lnum, buf, offs, rlen);
1685 return 0;
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
1694 * This functions returns %0 on success or a negative error code on failure.
1696 static int validate_data_node(struct ubifs_info *c, void *buf,
1697 struct ubifs_zbranch *zbr)
1699 union ubifs_key key1;
1700 struct ubifs_ch *ch = buf;
1701 int err, len;
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;
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;
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;
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;
1731 return 0;
1733 out_err:
1734 err = -EINVAL;
1735 out:
1736 ubifs_err("bad node at LEB %d:%d", zbr->lnum, zbr->offs);
1737 dbg_dump_node(c, buf);
1738 dbg_dump_stack();
1739 return err;
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
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.
1752 int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu)
1754 int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i;
1755 struct ubifs_wbuf *wbuf;
1756 void *buf;
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;
1765 /* Do the read */
1766 wbuf = ubifs_get_wbuf(c, lnum);
1767 if (wbuf)
1768 err = read_wbuf(wbuf, bu->buf, len, lnum, offs);
1769 else
1770 err = ubi_read(c->ubi, lnum, bu->buf, offs, len);
1772 /* Check for a race with GC */
1773 if (maybe_leb_gced(c, lnum, bu->gc_seq))
1774 return -EAGAIN;
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;
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);
1793 return 0;
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
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.
1809 static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1810 void *node, const struct qstr *nm)
1812 int found, n, err;
1813 struct ubifs_znode *znode;
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;
1826 ubifs_assert(n >= 0);
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;
1837 err = tnc_read_node_nm(c, &znode->zbranch[n], node);
1839 out_unlock:
1840 mutex_unlock(&c->tnc_mutex);
1841 return err;
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
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.
1857 int ubifs_tnc_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1858 void *node, const struct qstr *nm)
1860 int err, len;
1861 const struct ubifs_dent_node *dent = node;
1864 * We assume that in most of the cases there are no name collisions and
1865 * 'ubifs_tnc_lookup()' returns us the right direntry.
1867 err = ubifs_tnc_lookup(c, key, node);
1868 if (err)
1869 return err;
1871 len = le16_to_cpu(dent->nlen);
1872 if (nm->len == len && !memcmp(dent->name, nm->name, len))
1873 return 0;
1876 * Unluckily, there are hash collisions and we have to iterate over
1877 * them look at each direntry with colliding name hash sequentially.
1879 return do_lookup_nm(c, key, node, nm);
1883 * correct_parent_keys - correct parent znodes' keys.
1884 * @c: UBIFS file-system description object
1885 * @znode: znode to correct parent znodes for
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.
1891 static void correct_parent_keys(const struct ubifs_info *c,
1892 struct ubifs_znode *znode)
1894 union ubifs_key *key, *key1;
1896 ubifs_assert(znode->parent);
1897 ubifs_assert(znode->iip == 0);
1899 key = &znode->zbranch[0].key;
1900 key1 = &znode->parent->zbranch[0].key;
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;
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
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.
1923 static void insert_zbranch(struct ubifs_znode *znode,
1924 const struct ubifs_zbranch *zbr, int n)
1926 int i;
1928 ubifs_assert(ubifs_zn_dirty(znode));
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;
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];
1942 znode->zbranch[n] = *zbr;
1943 znode->child_cnt += 1;
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.
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.
1959 if (n == 0)
1960 znode->alt = 1;
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
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.
1975 static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode,
1976 struct ubifs_zbranch *zbr, int n)
1978 struct ubifs_znode *zn, *zi, *zp;
1979 int i, keep, move, appending = 0;
1980 union ubifs_key *key = &zbr->key, *key1;
1982 ubifs_assert(n >= 0 && n <= c->fanout);
1984 /* Implement naive insert for now */
1985 again:
1986 zp = znode->parent;
1987 if (znode->child_cnt < c->fanout) {
1988 ubifs_assert(n != c->fanout);
1989 dbg_tnc("inserted at %d level %d, key %s", n, znode->level,
1990 DBGKEY(key));
1992 insert_zbranch(znode, zbr, n);
1994 /* Ensure parent's key is correct */
1995 if (n == 0 && zp && znode->iip == 0)
1996 correct_parent_keys(c, znode);
1998 return 0;
2002 * Unfortunately, @znode does not have more empty slots and we have to
2003 * split it.
2005 dbg_tnc("splitting level %d, key %s", znode->level, DBGKEY(key));
2007 if (znode->alt)
2009 * We can no longer be sure of finding this znode by key, so we
2010 * record it in the old_idx tree.
2012 ins_clr_old_idx_znode(c, znode);
2014 zn = kzalloc(c->max_znode_sz, GFP_NOFS);
2015 if (!zn)
2016 return -ENOMEM;
2017 zn->parent = zp;
2018 zn->level = znode->level;
2020 /* Decide where to split */
2021 if (znode->level == 0 && key_type(c, key) == UBIFS_DATA_KEY) {
2022 /* Try not to split consecutive data keys */
2023 if (n == c->fanout) {
2024 key1 = &znode->zbranch[n - 1].key;
2025 if (key_inum(c, key1) == key_inum(c, key) &&
2026 key_type(c, key1) == UBIFS_DATA_KEY)
2027 appending = 1;
2028 } else
2029 goto check_split;
2030 } else if (appending && n != c->fanout) {
2031 /* Try not to split consecutive data keys */
2032 appending = 0;
2033 check_split:
2034 if (n >= (c->fanout + 1) / 2) {
2035 key1 = &znode->zbranch[0].key;
2036 if (key_inum(c, key1) == key_inum(c, key) &&
2037 key_type(c, key1) == UBIFS_DATA_KEY) {
2038 key1 = &znode->zbranch[n].key;
2039 if (key_inum(c, key1) != key_inum(c, key) ||
2040 key_type(c, key1) != UBIFS_DATA_KEY) {
2041 keep = n;
2042 move = c->fanout - keep;
2043 zi = znode;
2044 goto do_split;
2050 if (appending) {
2051 keep = c->fanout;
2052 move = 0;
2053 } else {
2054 keep = (c->fanout + 1) / 2;
2055 move = c->fanout - keep;
2059 * Although we don't at present, we could look at the neighbors and see
2060 * if we can move some zbranches there.
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;
2077 do_split:
2079 __set_bit(DIRTY_ZNODE, &zn->flags);
2080 atomic_long_inc(&c->dirty_zn_cnt);
2082 zn->child_cnt = move;
2083 znode->child_cnt = keep;
2085 dbg_tnc("moving %d, keeping %d", move, keep);
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;
2098 /* Insert new key and branch */
2099 dbg_tnc("inserting at %d level %d, key %s", n, zn->level, DBGKEY(key));
2101 insert_zbranch(zi, zbr, n);
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);
2108 /* Locate insertion point */
2109 n = znode->iip + 1;
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;
2119 goto again;
2122 /* We have to split root znode */
2123 dbg_tnc("creating new zroot at level %d", znode->level + 1);
2125 zi = kzalloc(c->max_znode_sz, GFP_NOFS);
2126 if (!zi)
2127 return -ENOMEM;
2129 zi->child_cnt = 2;
2130 zi->level = znode->level + 1;
2132 __set_bit(DIRTY_ZNODE, &zi->flags);
2133 atomic_long_inc(&c->dirty_zn_cnt);
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;
2143 c->zroot.lnum = 0;
2144 c->zroot.offs = 0;
2145 c->zroot.len = 0;
2146 c->zroot.znode = zi;
2148 zn->parent = zi;
2149 zn->iip = 1;
2150 znode->parent = zi;
2151 znode->iip = 0;
2153 return 0;
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
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.
2168 int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum,
2169 int offs, int len)
2171 int found, n, err = 0;
2172 struct ubifs_znode *znode;
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;
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];
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);
2200 return err;
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
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.
2217 int ubifs_tnc_replace(struct ubifs_info *c, const union ubifs_key *key,
2218 int old_lnum, int old_offs, int lnum, int offs, int len)
2220 int found, n, err = 0;
2221 struct ubifs_znode *znode;
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;
2232 if (found == 1) {
2233 struct ubifs_zbranch *zbr = &znode->zbranch[n];
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;
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;
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;
2277 if (!found)
2278 err = ubifs_add_dirt(c, lnum, len);
2280 if (!err)
2281 err = dbg_check_tnc(c, 0);
2283 out_unlock:
2284 mutex_unlock(&c->tnc_mutex);
2285 return err;
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
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.
2300 int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
2301 int lnum, int offs, int len, const struct qstr *nm)
2303 int found, n, err = 0;
2304 struct ubifs_znode *znode;
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;
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;
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;
2336 if (found == 1) {
2337 struct ubifs_zbranch *zbr = &znode->zbranch[n];
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;
2348 if (!found) {
2349 struct ubifs_zbranch zbr;
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) {
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.
2366 struct qstr noname = { .len = 0, .name = "" };
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);
2376 out_unlock:
2377 if (!err)
2378 err = dbg_check_tnc(c, 0);
2379 mutex_unlock(&c->tnc_mutex);
2380 return err;
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
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.
2392 static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n)
2394 struct ubifs_zbranch *zbr;
2395 struct ubifs_znode *zp;
2396 int i, err;
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));
2403 zbr = &znode->zbranch[n];
2404 lnc_free(zbr);
2406 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2407 if (err) {
2408 dbg_dump_znode(c, znode);
2409 return err;
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;
2417 if (znode->child_cnt > 0)
2418 return 0;
2421 * This was the last zbranch, we have to delete this znode from the
2422 * parent.
2425 do {
2426 ubifs_assert(!test_bit(OBSOLETE_ZNODE, &znode->flags));
2427 ubifs_assert(ubifs_zn_dirty(znode));
2429 zp = znode->parent;
2430 n = znode->iip;
2432 atomic_long_dec(&c->dirty_zn_cnt);
2434 err = insert_old_idx_znode(c, znode);
2435 if (err)
2436 return err;
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 */
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;
2457 * If this is the root and it has only 1 child then
2458 * collapse the tree.
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;
2478 c->zroot.lnum = zbr->lnum;
2479 c->zroot.offs = zbr->offs;
2480 c->zroot.len = zbr->len;
2481 c->zroot.znode = znode;
2482 ubifs_assert(!test_bit(OBSOLETE_ZNODE,
2483 &zp->flags));
2484 ubifs_assert(test_bit(DIRTY_ZNODE, &zp->flags));
2485 atomic_long_dec(&c->dirty_zn_cnt);
2487 if (zp->cnext) {
2488 __set_bit(OBSOLETE_ZNODE, &zp->flags);
2489 atomic_long_inc(&c->clean_zn_cnt);
2490 atomic_long_inc(&ubifs_clean_zn_cnt);
2491 } else
2492 kfree(zp);
2496 return 0;
2500 * ubifs_tnc_remove - remove an index entry of a node.
2501 * @c: UBIFS file-system description object
2502 * @key: key of node
2504 * Returns %0 on success or negative error code on failure.
2506 int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key)
2508 int found, n, err = 0;
2509 struct ubifs_znode *znode;
2511 mutex_lock(&c->tnc_mutex);
2512 dbg_tnc("key %s", DBGKEY(key));
2513 found = lookup_level0_dirty(c, key, &znode, &n);
2514 if (found < 0) {
2515 err = found;
2516 goto out_unlock;
2518 if (found == 1)
2519 err = tnc_delete(c, znode, n);
2520 if (!err)
2521 err = dbg_check_tnc(c, 0);
2523 out_unlock:
2524 mutex_unlock(&c->tnc_mutex);
2525 return err;
2529 * ubifs_tnc_remove_nm - remove an index entry for a "hashed" node.
2530 * @c: UBIFS file-system description object
2531 * @key: key of node
2532 * @nm: directory entry name
2534 * Returns %0 on success or negative error code on failure.
2536 int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
2537 const struct qstr *nm)
2539 int n, err;
2540 struct ubifs_znode *znode;
2542 mutex_lock(&c->tnc_mutex);
2543 dbg_tnc("%.*s, key %s", nm->len, nm->name, DBGKEY(key));
2544 err = lookup_level0_dirty(c, key, &znode, &n);
2545 if (err < 0)
2546 goto out_unlock;
2548 if (err) {
2549 if (c->replaying)
2550 err = fallible_resolve_collision(c, key, &znode, &n,
2551 nm, 0);
2552 else
2553 err = resolve_collision(c, key, &znode, &n, nm);
2554 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
2555 if (err < 0)
2556 goto out_unlock;
2557 if (err) {
2558 /* Ensure the znode is dirtied */
2559 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2560 znode = dirty_cow_bottom_up(c, znode);
2561 if (IS_ERR(znode)) {
2562 err = PTR_ERR(znode);
2563 goto out_unlock;
2566 err = tnc_delete(c, znode, n);
2570 out_unlock:
2571 if (!err)
2572 err = dbg_check_tnc(c, 0);
2573 mutex_unlock(&c->tnc_mutex);
2574 return err;
2578 * key_in_range - determine if a key falls within a range of keys.
2579 * @c: UBIFS file-system description object
2580 * @key: key to check
2581 * @from_key: lowest key in range
2582 * @to_key: highest key in range
2584 * This function returns %1 if the key is in range and %0 otherwise.
2586 static int key_in_range(struct ubifs_info *c, union ubifs_key *key,
2587 union ubifs_key *from_key, union ubifs_key *to_key)
2589 if (keys_cmp(c, key, from_key) < 0)
2590 return 0;
2591 if (keys_cmp(c, key, to_key) > 0)
2592 return 0;
2593 return 1;
2597 * ubifs_tnc_remove_range - remove index entries in range.
2598 * @c: UBIFS file-system description object
2599 * @from_key: lowest key to remove
2600 * @to_key: highest key to remove
2602 * This function removes index entries starting at @from_key and ending at
2603 * @to_key. This function returns zero in case of success and a negative error
2604 * code in case of failure.
2606 int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key,
2607 union ubifs_key *to_key)
2609 int i, n, k, err = 0;
2610 struct ubifs_znode *znode;
2611 union ubifs_key *key;
2613 mutex_lock(&c->tnc_mutex);
2614 while (1) {
2615 /* Find first level 0 znode that contains keys to remove */
2616 err = ubifs_lookup_level0(c, from_key, &znode, &n);
2617 if (err < 0)
2618 goto out_unlock;
2620 if (err)
2621 key = from_key;
2622 else {
2623 err = tnc_next(c, &znode, &n);
2624 if (err == -ENOENT) {
2625 err = 0;
2626 goto out_unlock;
2628 if (err < 0)
2629 goto out_unlock;
2630 key = &znode->zbranch[n].key;
2631 if (!key_in_range(c, key, from_key, to_key)) {
2632 err = 0;
2633 goto out_unlock;
2637 /* Ensure the znode is dirtied */
2638 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2639 znode = dirty_cow_bottom_up(c, znode);
2640 if (IS_ERR(znode)) {
2641 err = PTR_ERR(znode);
2642 goto out_unlock;
2646 /* Remove all keys in range except the first */
2647 for (i = n + 1, k = 0; i < znode->child_cnt; i++, k++) {
2648 key = &znode->zbranch[i].key;
2649 if (!key_in_range(c, key, from_key, to_key))
2650 break;
2651 lnc_free(&znode->zbranch[i]);
2652 err = ubifs_add_dirt(c, znode->zbranch[i].lnum,
2653 znode->zbranch[i].len);
2654 if (err) {
2655 dbg_dump_znode(c, znode);
2656 goto out_unlock;
2658 dbg_tnc("removing %s", DBGKEY(key));
2660 if (k) {
2661 for (i = n + 1 + k; i < znode->child_cnt; i++)
2662 znode->zbranch[i - k] = znode->zbranch[i];
2663 znode->child_cnt -= k;
2666 /* Now delete the first */
2667 err = tnc_delete(c, znode, n);
2668 if (err)
2669 goto out_unlock;
2672 out_unlock:
2673 if (!err)
2674 err = dbg_check_tnc(c, 0);
2675 mutex_unlock(&c->tnc_mutex);
2676 return err;
2680 * ubifs_tnc_remove_ino - remove an inode from TNC.
2681 * @c: UBIFS file-system description object
2682 * @inum: inode number to remove
2684 * This function remove inode @inum and all the extended attributes associated
2685 * with the anode from TNC and returns zero in case of success or a negative
2686 * error code in case of failure.
2688 int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum)
2690 union ubifs_key key1, key2;
2691 struct ubifs_dent_node *xent, *pxent = NULL;
2692 struct qstr nm = { .name = NULL };
2694 dbg_tnc("ino %lu", (unsigned long)inum);
2697 * Walk all extended attribute entries and remove them together with
2698 * corresponding extended attribute inodes.
2700 lowest_xent_key(c, &key1, inum);
2701 while (1) {
2702 ino_t xattr_inum;
2703 int err;
2705 xent = ubifs_tnc_next_ent(c, &key1, &nm);
2706 if (IS_ERR(xent)) {
2707 err = PTR_ERR(xent);
2708 if (err == -ENOENT)
2709 break;
2710 return err;
2713 xattr_inum = le64_to_cpu(xent->inum);
2714 dbg_tnc("xent '%s', ino %lu", xent->name,
2715 (unsigned long)xattr_inum);
2717 nm.name = xent->name;
2718 nm.len = le16_to_cpu(xent->nlen);
2719 err = ubifs_tnc_remove_nm(c, &key1, &nm);
2720 if (err) {
2721 kfree(xent);
2722 return err;
2725 lowest_ino_key(c, &key1, xattr_inum);
2726 highest_ino_key(c, &key2, xattr_inum);
2727 err = ubifs_tnc_remove_range(c, &key1, &key2);
2728 if (err) {
2729 kfree(xent);
2730 return err;
2733 kfree(pxent);
2734 pxent = xent;
2735 key_read(c, &xent->key, &key1);
2738 kfree(pxent);
2739 lowest_ino_key(c, &key1, inum);
2740 highest_ino_key(c, &key2, inum);
2742 return ubifs_tnc_remove_range(c, &key1, &key2);
2746 * ubifs_tnc_next_ent - walk directory or extended attribute entries.
2747 * @c: UBIFS file-system description object
2748 * @key: key of last entry
2749 * @nm: name of last entry found or %NULL
2751 * This function finds and reads the next directory or extended attribute entry
2752 * after the given key (@key) if there is one. @nm is used to resolve
2753 * collisions.
2755 * If the name of the current entry is not known and only the key is known,
2756 * @nm->name has to be %NULL. In this case the semantics of this function is a
2757 * little bit different and it returns the entry corresponding to this key, not
2758 * the next one. If the key was not found, the closest "right" entry is
2759 * returned.
2761 * If the fist entry has to be found, @key has to contain the lowest possible
2762 * key value for this inode and @name has to be %NULL.
2764 * This function returns the found directory or extended attribute entry node
2765 * in case of success, %-ENOENT is returned if no entry was found, and a
2766 * negative error code is returned in case of failure.
2768 struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c,
2769 union ubifs_key *key,
2770 const struct qstr *nm)
2772 int n, err, type = key_type(c, key);
2773 struct ubifs_znode *znode;
2774 struct ubifs_dent_node *dent;
2775 struct ubifs_zbranch *zbr;
2776 union ubifs_key *dkey;
2778 dbg_tnc("%s %s", nm->name ? (char *)nm->name : "(lowest)", DBGKEY(key));
2779 ubifs_assert(is_hash_key(c, key));
2781 mutex_lock(&c->tnc_mutex);
2782 err = ubifs_lookup_level0(c, key, &znode, &n);
2783 if (unlikely(err < 0))
2784 goto out_unlock;
2786 if (nm->name) {
2787 if (err) {
2788 /* Handle collisions */
2789 err = resolve_collision(c, key, &znode, &n, nm);
2790 dbg_tnc("rc returned %d, znode %p, n %d",
2791 err, znode, n);
2792 if (unlikely(err < 0))
2793 goto out_unlock;
2796 /* Now find next entry */
2797 err = tnc_next(c, &znode, &n);
2798 if (unlikely(err))
2799 goto out_unlock;
2800 } else {
2802 * The full name of the entry was not given, in which case the
2803 * behavior of this function is a little different and it
2804 * returns current entry, not the next one.
2806 if (!err) {
2808 * However, the given key does not exist in the TNC
2809 * tree and @znode/@n variables contain the closest
2810 * "preceding" element. Switch to the next one.
2812 err = tnc_next(c, &znode, &n);
2813 if (err)
2814 goto out_unlock;
2818 zbr = &znode->zbranch[n];
2819 dent = kmalloc(zbr->len, GFP_NOFS);
2820 if (unlikely(!dent)) {
2821 err = -ENOMEM;
2822 goto out_unlock;
2826 * The above 'tnc_next()' call could lead us to the next inode, check
2827 * this.
2829 dkey = &zbr->key;
2830 if (key_inum(c, dkey) != key_inum(c, key) ||
2831 key_type(c, dkey) != type) {
2832 err = -ENOENT;
2833 goto out_free;
2836 err = tnc_read_node_nm(c, zbr, dent);
2837 if (unlikely(err))
2838 goto out_free;
2840 mutex_unlock(&c->tnc_mutex);
2841 return dent;
2843 out_free:
2844 kfree(dent);
2845 out_unlock:
2846 mutex_unlock(&c->tnc_mutex);
2847 return ERR_PTR(err);
2851 * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit.
2852 * @c: UBIFS file-system description object
2854 * Destroy left-over obsolete znodes from a failed commit.
2856 static void tnc_destroy_cnext(struct ubifs_info *c)
2858 struct ubifs_znode *cnext;
2860 if (!c->cnext)
2861 return;
2862 ubifs_assert(c->cmt_state == COMMIT_BROKEN);
2863 cnext = c->cnext;
2864 do {
2865 struct ubifs_znode *znode = cnext;
2867 cnext = cnext->cnext;
2868 if (test_bit(OBSOLETE_ZNODE, &znode->flags))
2869 kfree(znode);
2870 } while (cnext && cnext != c->cnext);
2874 * ubifs_tnc_close - close TNC subsystem and free all related resources.
2875 * @c: UBIFS file-system description object
2877 void ubifs_tnc_close(struct ubifs_info *c)
2879 long clean_freed;
2881 tnc_destroy_cnext(c);
2882 if (c->zroot.znode) {
2883 clean_freed = ubifs_destroy_tnc_subtree(c->zroot.znode);
2884 atomic_long_sub(clean_freed, &ubifs_clean_zn_cnt);
2886 kfree(c->gap_lebs);
2887 kfree(c->ilebs);
2888 destroy_old_idx(c);
2892 * left_znode - get the znode to the left.
2893 * @c: UBIFS file-system description object
2894 * @znode: znode
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.
2899 static struct ubifs_znode *left_znode(struct ubifs_info *c,
2900 struct ubifs_znode *znode)
2902 int level = znode->level;
2904 while (1) {
2905 int n = znode->iip - 1;
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;
2922 break;
2925 return znode;
2929 * right_znode - get the znode to the right.
2930 * @c: UBIFS file-system description object
2931 * @znode: znode
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.
2936 static struct ubifs_znode *right_znode(struct ubifs_info *c,
2937 struct ubifs_znode *znode)
2939 int level = znode->level;
2941 while (1) {
2942 int n = znode->iip + 1;
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;
2958 break;
2961 return znode;
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
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.
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).
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.
2989 static struct ubifs_znode *lookup_znode(struct ubifs_info *c,
2990 union ubifs_key *key, int level,
2991 int lnum, int offs)
2993 struct ubifs_znode *znode, *zn;
2994 int n, nn;
2996 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
2999 * The arguments have probably been read off flash, so don't assume
3000 * they are valid.
3002 if (level < 0)
3003 return ERR_PTR(-EINVAL);
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;
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) {
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.
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);
3037 if (znode->level == level + 1)
3038 break;
3039 znode = get_znode(c, znode, n);
3040 if (IS_ERR(znode))
3041 return znode;
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;
3050 * The key is not unique and so may be also in the znodes to either
3051 * side.
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;
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;
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;
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;
3098 return NULL;
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
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.
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.
3118 int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level,
3119 int lnum, int offs)
3121 struct ubifs_znode *znode;
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);
3129 return ubifs_zn_dirty(znode) ? 1 : 2;
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
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.
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.
3145 static int is_leaf_node_in_tnc(struct ubifs_info *c, union ubifs_key *key,
3146 int lnum, int offs)
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);
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;
3164 * Because the key is not unique, we have to look left
3165 * and right as well
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 */
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;
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 */
3198 return 0;
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
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.
3215 int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level,
3216 int lnum, int offs, int is_idx)
3218 int err;
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);
3236 out_unlock:
3237 mutex_unlock(&c->tnc_mutex);
3238 return err;
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
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.
3255 int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level,
3256 int lnum, int offs)
3258 struct ubifs_znode *znode;
3259 int err = 0;
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;
3269 znode = dirty_cow_bottom_up(c, znode);
3270 if (IS_ERR(znode)) {
3271 err = PTR_ERR(znode);
3272 goto out_unlock;
3275 out_unlock:
3276 mutex_unlock(&c->tnc_mutex);
3277 return err;
3280 #ifdef CONFIG_UBIFS_FS_DEBUG
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
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.
3293 int dbg_check_inode_size(struct ubifs_info *c, const struct inode *inode,
3294 loff_t size)
3296 int err, n;
3297 union ubifs_key from_key, to_key, *key;
3298 struct ubifs_znode *znode;
3299 unsigned int block;
3301 if (!S_ISREG(inode->i_mode))
3302 return 0;
3303 if (!(ubifs_chk_flags & UBIFS_CHK_GEN))
3304 return 0;
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);
3310 mutex_lock(&c->tnc_mutex);
3311 err = ubifs_lookup_level0(c, &from_key, &znode, &n);
3312 if (err < 0)
3313 goto out_unlock;
3315 if (err) {
3316 err = -EINVAL;
3317 key = &from_key;
3318 goto out_dump;
3321 err = tnc_next(c, &znode, &n);
3322 if (err == -ENOENT) {
3323 err = 0;
3324 goto out_unlock;
3326 if (err < 0)
3327 goto out_unlock;
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;
3334 out_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 dbg_dump_inode(c, inode);
3340 dbg_dump_stack();
3341 err = -EINVAL;
3343 out_unlock:
3344 mutex_unlock(&c->tnc_mutex);
3345 return err;
3348 #endif /* CONFIG_UBIFS_FS_DEBUG */