2 * This file is part of UBIFS.
4 * Copyright (C) 2006-2008 Nokia Corporation.
6 * SPDX-License-Identifier: GPL-2.0+
8 * Authors: Adrian Hunter
9 * Artem Bityutskiy (Битюцкий Артём)
13 * This file implements TNC (Tree Node Cache) which caches indexing nodes of
16 * At the moment the locking rules of the TNC tree are quite simple and
17 * straightforward. We just have a mutex and lock it when we traverse the
18 * tree. If a znode is not in memory, we read it from flash while still having
24 #include <linux/crc32.h>
25 #include <linux/slab.h>
27 #include <linux/compat.h>
28 #include <linux/err.h>
29 #include <linux/stat.h>
34 * Returned codes of 'matches_name()' and 'fallible_matches_name()' functions.
35 * @NAME_LESS: name corresponding to the first argument is less than second
36 * @NAME_MATCHES: names match
37 * @NAME_GREATER: name corresponding to the second argument is greater than
39 * @NOT_ON_MEDIA: node referred by zbranch does not exist on the media
41 * These constants were introduce to improve readability.
51 * insert_old_idx - record an index node obsoleted since the last commit start.
52 * @c: UBIFS file-system description object
53 * @lnum: LEB number of obsoleted index node
54 * @offs: offset of obsoleted index node
56 * Returns %0 on success, and a negative error code on failure.
58 * For recovery, there must always be a complete intact version of the index on
59 * flash at all times. That is called the "old index". It is the index as at the
60 * time of the last successful commit. Many of the index nodes in the old index
61 * may be dirty, but they must not be erased until the next successful commit
62 * (at which point that index becomes the old index).
64 * That means that the garbage collection and the in-the-gaps method of
65 * committing must be able to determine if an index node is in the old index.
66 * Most of the old index nodes can be found by looking up the TNC using the
67 * 'lookup_znode()' function. However, some of the old index nodes may have
68 * been deleted from the current index or may have been changed so much that
69 * they cannot be easily found. In those cases, an entry is added to an RB-tree.
70 * That is what this function does. The RB-tree is ordered by LEB number and
71 * offset because they uniquely identify the old index node.
73 static int insert_old_idx(struct ubifs_info *c, int lnum, int offs)
75 struct ubifs_old_idx *old_idx, *o;
76 struct rb_node **p, *parent = NULL;
78 old_idx = kmalloc(sizeof(struct ubifs_old_idx), GFP_NOFS);
79 if (unlikely(!old_idx))
84 p = &c->old_idx.rb_node;
87 o = rb_entry(parent, struct ubifs_old_idx, rb);
90 else if (lnum > o->lnum)
92 else if (offs < o->offs)
94 else if (offs > o->offs)
97 ubifs_err("old idx added twice!");
102 rb_link_node(&old_idx->rb, parent, p);
103 rb_insert_color(&old_idx->rb, &c->old_idx);
108 * insert_old_idx_znode - record a znode obsoleted since last commit start.
109 * @c: UBIFS file-system description object
110 * @znode: znode of obsoleted index node
112 * Returns %0 on success, and a negative error code on failure.
114 int insert_old_idx_znode(struct ubifs_info *c, struct ubifs_znode *znode)
117 struct ubifs_zbranch *zbr;
119 zbr = &znode->parent->zbranch[znode->iip];
121 return insert_old_idx(c, zbr->lnum, zbr->offs);
124 return insert_old_idx(c, c->zroot.lnum,
130 * ins_clr_old_idx_znode - record a znode obsoleted since last commit start.
131 * @c: UBIFS file-system description object
132 * @znode: znode of obsoleted index node
134 * Returns %0 on success, and a negative error code on failure.
136 static int ins_clr_old_idx_znode(struct ubifs_info *c,
137 struct ubifs_znode *znode)
142 struct ubifs_zbranch *zbr;
144 zbr = &znode->parent->zbranch[znode->iip];
146 err = insert_old_idx(c, zbr->lnum, zbr->offs);
155 err = insert_old_idx(c, c->zroot.lnum, c->zroot.offs);
166 * destroy_old_idx - destroy the old_idx RB-tree.
167 * @c: UBIFS file-system description object
169 * During start commit, the old_idx RB-tree is used to avoid overwriting index
170 * nodes that were in the index last commit but have since been deleted. This
171 * is necessary for recovery i.e. the old index must be kept intact until the
172 * new index is successfully written. The old-idx RB-tree is used for the
173 * in-the-gaps method of writing index nodes and is destroyed every commit.
175 void destroy_old_idx(struct ubifs_info *c)
177 struct ubifs_old_idx *old_idx, *n;
179 rbtree_postorder_for_each_entry_safe(old_idx, n, &c->old_idx, rb)
182 c->old_idx = RB_ROOT;
186 * copy_znode - copy a dirty znode.
187 * @c: UBIFS file-system description object
188 * @znode: znode to copy
190 * A dirty znode being committed may not be changed, so it is copied.
192 static struct ubifs_znode *copy_znode(struct ubifs_info *c,
193 struct ubifs_znode *znode)
195 struct ubifs_znode *zn;
197 zn = kmalloc(c->max_znode_sz, GFP_NOFS);
199 return ERR_PTR(-ENOMEM);
201 memcpy(zn, znode, c->max_znode_sz);
203 __set_bit(DIRTY_ZNODE, &zn->flags);
204 __clear_bit(COW_ZNODE, &zn->flags);
206 ubifs_assert(!ubifs_zn_obsolete(znode));
207 __set_bit(OBSOLETE_ZNODE, &znode->flags);
209 if (znode->level != 0) {
211 const int n = zn->child_cnt;
213 /* The children now have new parent */
214 for (i = 0; i < n; i++) {
215 struct ubifs_zbranch *zbr = &zn->zbranch[i];
218 zbr->znode->parent = zn;
222 atomic_long_inc(&c->dirty_zn_cnt);
227 * add_idx_dirt - add dirt due to a dirty znode.
228 * @c: UBIFS file-system description object
229 * @lnum: LEB number of index node
230 * @dirt: size of index node
232 * This function updates lprops dirty space and the new size of the index.
234 static int add_idx_dirt(struct ubifs_info *c, int lnum, int dirt)
236 c->calc_idx_sz -= ALIGN(dirt, 8);
237 return ubifs_add_dirt(c, lnum, dirt);
241 * dirty_cow_znode - ensure a znode is not being committed.
242 * @c: UBIFS file-system description object
243 * @zbr: branch of znode to check
245 * Returns dirtied znode on success or negative error code on failure.
247 static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c,
248 struct ubifs_zbranch *zbr)
250 struct ubifs_znode *znode = zbr->znode;
251 struct ubifs_znode *zn;
254 if (!ubifs_zn_cow(znode)) {
255 /* znode is not being committed */
256 if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) {
257 atomic_long_inc(&c->dirty_zn_cnt);
258 atomic_long_dec(&c->clean_zn_cnt);
259 atomic_long_dec(&ubifs_clean_zn_cnt);
260 err = add_idx_dirt(c, zbr->lnum, zbr->len);
267 zn = copy_znode(c, znode);
272 err = insert_old_idx(c, zbr->lnum, zbr->offs);
275 err = add_idx_dirt(c, zbr->lnum, zbr->len);
290 * lnc_add - add a leaf node to the leaf node cache.
291 * @c: UBIFS file-system description object
292 * @zbr: zbranch of leaf node
295 * Leaf nodes are non-index nodes directory entry nodes or data nodes. The
296 * purpose of the leaf node cache is to save re-reading the same leaf node over
297 * and over again. Most things are cached by VFS, however the file system must
298 * cache directory entries for readdir and for resolving hash collisions. The
299 * present implementation of the leaf node cache is extremely simple, and
300 * allows for error returns that are not used but that may be needed if a more
301 * complex implementation is created.
303 * Note, this function does not add the @node object to LNC directly, but
304 * allocates a copy of the object and adds the copy to LNC. The reason for this
305 * is that @node has been allocated outside of the TNC subsystem and will be
306 * used with @c->tnc_mutex unlock upon return from the TNC subsystem. But LNC
307 * may be changed at any time, e.g. freed by the shrinker.
309 static int lnc_add(struct ubifs_info *c, struct ubifs_zbranch *zbr,
314 const struct ubifs_dent_node *dent = node;
316 ubifs_assert(!zbr->leaf);
317 ubifs_assert(zbr->len != 0);
318 ubifs_assert(is_hash_key(c, &zbr->key));
320 err = ubifs_validate_entry(c, dent);
323 ubifs_dump_node(c, dent);
327 lnc_node = kmemdup(node, zbr->len, GFP_NOFS);
329 /* We don't have to have the cache, so no error */
332 zbr->leaf = lnc_node;
337 * lnc_add_directly - add a leaf node to the leaf-node-cache.
338 * @c: UBIFS file-system description object
339 * @zbr: zbranch of leaf node
342 * This function is similar to 'lnc_add()', but it does not create a copy of
343 * @node but inserts @node to TNC directly.
345 static int lnc_add_directly(struct ubifs_info *c, struct ubifs_zbranch *zbr,
350 ubifs_assert(!zbr->leaf);
351 ubifs_assert(zbr->len != 0);
353 err = ubifs_validate_entry(c, node);
356 ubifs_dump_node(c, node);
365 * lnc_free - remove a leaf node from the leaf node cache.
366 * @zbr: zbranch of leaf node
369 static void lnc_free(struct ubifs_zbranch *zbr)
378 * tnc_read_node_nm - read a "hashed" leaf node.
379 * @c: UBIFS file-system description object
380 * @zbr: key and position of the node
381 * @node: node is returned here
383 * This function reads a "hashed" node defined by @zbr from the leaf node cache
384 * (in it is there) or from the hash media, in which case the node is also
385 * added to LNC. Returns zero in case of success or a negative negative error
386 * code in case of failure.
388 static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr,
393 ubifs_assert(is_hash_key(c, &zbr->key));
396 /* Read from the leaf node cache */
397 ubifs_assert(zbr->len != 0);
398 memcpy(node, zbr->leaf, zbr->len);
402 err = ubifs_tnc_read_node(c, zbr, node);
406 /* Add the node to the leaf node cache */
407 err = lnc_add(c, zbr, node);
412 * try_read_node - read a node if it is a node.
413 * @c: UBIFS file-system description object
414 * @buf: buffer to read to
416 * @len: node length (not aligned)
417 * @lnum: LEB number of node to read
418 * @offs: offset of node to read
420 * This function tries to read a node of known type and length, checks it and
421 * stores it in @buf. This function returns %1 if a node is present and %0 if
422 * a node is not present. A negative error code is returned for I/O errors.
423 * This function performs that same function as ubifs_read_node except that
424 * it does not require that there is actually a node present and instead
425 * the return code indicates if a node was read.
427 * Note, this function does not check CRC of data nodes if @c->no_chk_data_crc
428 * is true (it is controlled by corresponding mount option). However, if
429 * @c->mounting or @c->remounting_rw is true (we are mounting or re-mounting to
430 * R/W mode), @c->no_chk_data_crc is ignored and CRC is checked. This is
431 * because during mounting or re-mounting from R/O mode to R/W mode we may read
432 * journal nodes (when replying the journal or doing the recovery) and the
433 * journal nodes may potentially be corrupted, so checking is required.
435 static int try_read_node(const struct ubifs_info *c, void *buf, int type,
436 int len, int lnum, int offs)
439 struct ubifs_ch *ch = buf;
440 uint32_t crc, node_crc;
442 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
444 err = ubifs_leb_read(c, lnum, buf, offs, len, 1);
446 ubifs_err("cannot read node type %d from LEB %d:%d, error %d",
447 type, lnum, offs, err);
451 if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC)
454 if (ch->node_type != type)
457 node_len = le32_to_cpu(ch->len);
461 if (type == UBIFS_DATA_NODE && c->no_chk_data_crc && !c->mounting &&
465 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
466 node_crc = le32_to_cpu(ch->crc);
474 * fallible_read_node - try to read a leaf node.
475 * @c: UBIFS file-system description object
476 * @key: key of node to read
477 * @zbr: position of node
478 * @node: node returned
480 * This function tries to read a node and returns %1 if the node is read, %0
481 * if the node is not present, and a negative error code in the case of error.
483 static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
484 struct ubifs_zbranch *zbr, void *node)
488 dbg_tnck(key, "LEB %d:%d, key ", zbr->lnum, zbr->offs);
490 ret = try_read_node(c, node, key_type(c, key), zbr->len, zbr->lnum,
493 union ubifs_key node_key;
494 struct ubifs_dent_node *dent = node;
496 /* All nodes have key in the same place */
497 key_read(c, &dent->key, &node_key);
498 if (keys_cmp(c, key, &node_key) != 0)
501 if (ret == 0 && c->replaying)
502 dbg_mntk(key, "dangling branch LEB %d:%d len %d, key ",
503 zbr->lnum, zbr->offs, zbr->len);
508 * matches_name - determine if a direntry or xattr entry matches a given name.
509 * @c: UBIFS file-system description object
510 * @zbr: zbranch of dent
513 * This function checks if xentry/direntry referred by zbranch @zbr matches name
514 * @nm. Returns %NAME_MATCHES if it does, %NAME_LESS if the name referred by
515 * @zbr is less than @nm, and %NAME_GREATER if it is greater than @nm. In case
516 * of failure, a negative error code is returned.
518 static int matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr,
519 const struct qstr *nm)
521 struct ubifs_dent_node *dent;
524 /* If possible, match against the dent in the leaf node cache */
526 dent = kmalloc(zbr->len, GFP_NOFS);
530 err = ubifs_tnc_read_node(c, zbr, dent);
534 /* Add the node to the leaf node cache */
535 err = lnc_add_directly(c, zbr, dent);
541 nlen = le16_to_cpu(dent->nlen);
542 err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
546 else if (nlen < nm->len)
561 * get_znode - get a TNC znode that may not be loaded yet.
562 * @c: UBIFS file-system description object
563 * @znode: parent znode
564 * @n: znode branch slot number
566 * This function returns the znode or a negative error code.
568 static struct ubifs_znode *get_znode(struct ubifs_info *c,
569 struct ubifs_znode *znode, int n)
571 struct ubifs_zbranch *zbr;
573 zbr = &znode->zbranch[n];
577 znode = ubifs_load_znode(c, zbr, znode, n);
582 * tnc_next - find next TNC entry.
583 * @c: UBIFS file-system description object
584 * @zn: znode is passed and returned here
585 * @n: znode branch slot number is passed and returned here
587 * This function returns %0 if the next TNC entry is found, %-ENOENT if there is
588 * no next entry, or a negative error code otherwise.
590 static int tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
592 struct ubifs_znode *znode = *zn;
596 if (nn < znode->child_cnt) {
601 struct ubifs_znode *zp;
608 if (nn < znode->child_cnt) {
609 znode = get_znode(c, znode, nn);
611 return PTR_ERR(znode);
612 while (znode->level != 0) {
613 znode = get_znode(c, znode, 0);
615 return PTR_ERR(znode);
627 * tnc_prev - find previous TNC entry.
628 * @c: UBIFS file-system description object
629 * @zn: znode is returned here
630 * @n: znode branch slot number is passed and returned here
632 * This function returns %0 if the previous TNC entry is found, %-ENOENT if
633 * there is no next entry, or a negative error code otherwise.
635 static int tnc_prev(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
637 struct ubifs_znode *znode = *zn;
645 struct ubifs_znode *zp;
653 znode = get_znode(c, znode, nn);
655 return PTR_ERR(znode);
656 while (znode->level != 0) {
657 nn = znode->child_cnt - 1;
658 znode = get_znode(c, znode, nn);
660 return PTR_ERR(znode);
662 nn = znode->child_cnt - 1;
672 * resolve_collision - resolve a collision.
673 * @c: UBIFS file-system description object
674 * @key: key of a directory or extended attribute entry
675 * @zn: znode is returned here
676 * @n: zbranch number is passed and returned here
677 * @nm: name of the entry
679 * This function is called for "hashed" keys to make sure that the found key
680 * really corresponds to the looked up node (directory or extended attribute
681 * entry). It returns %1 and sets @zn and @n if the collision is resolved.
682 * %0 is returned if @nm is not found and @zn and @n are set to the previous
683 * entry, i.e. to the entry after which @nm could follow if it were in TNC.
684 * This means that @n may be set to %-1 if the leftmost key in @zn is the
685 * previous one. A negative error code is returned on failures.
687 static int resolve_collision(struct ubifs_info *c, const union ubifs_key *key,
688 struct ubifs_znode **zn, int *n,
689 const struct qstr *nm)
693 err = matches_name(c, &(*zn)->zbranch[*n], nm);
694 if (unlikely(err < 0))
696 if (err == NAME_MATCHES)
699 if (err == NAME_GREATER) {
702 err = tnc_prev(c, zn, n);
703 if (err == -ENOENT) {
704 ubifs_assert(*n == 0);
710 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
712 * We have found the branch after which we would
713 * like to insert, but inserting in this znode
714 * may still be wrong. Consider the following 3
715 * znodes, in the case where we are resolving a
716 * collision with Key2.
719 * ----------------------
720 * level 1 | Key0 | Key1 |
721 * -----------------------
723 * znode za | | znode zb
724 * ------------ ------------
725 * level 0 | Key0 | | Key2 |
726 * ------------ ------------
728 * The lookup finds Key2 in znode zb. Lets say
729 * there is no match and the name is greater so
730 * we look left. When we find Key0, we end up
731 * here. If we return now, we will insert into
732 * znode za at slot n = 1. But that is invalid
733 * according to the parent's keys. Key2 must
734 * be inserted into znode zb.
736 * Note, this problem is not relevant for the
737 * case when we go right, because
738 * 'tnc_insert()' would correct the parent key.
740 if (*n == (*zn)->child_cnt - 1) {
741 err = tnc_next(c, zn, n);
743 /* Should be impossible */
749 ubifs_assert(*n == 0);
754 err = matches_name(c, &(*zn)->zbranch[*n], nm);
757 if (err == NAME_LESS)
759 if (err == NAME_MATCHES)
761 ubifs_assert(err == NAME_GREATER);
765 struct ubifs_znode *znode = *zn;
769 err = tnc_next(c, &znode, &nn);
774 if (keys_cmp(c, &znode->zbranch[nn].key, key))
776 err = matches_name(c, &znode->zbranch[nn], nm);
779 if (err == NAME_GREATER)
783 if (err == NAME_MATCHES)
785 ubifs_assert(err == NAME_LESS);
791 * fallible_matches_name - determine if a dent matches a given name.
792 * @c: UBIFS file-system description object
793 * @zbr: zbranch of dent
796 * This is a "fallible" version of 'matches_name()' function which does not
797 * panic if the direntry/xentry referred by @zbr does not exist on the media.
799 * This function checks if xentry/direntry referred by zbranch @zbr matches name
800 * @nm. Returns %NAME_MATCHES it does, %NAME_LESS if the name referred by @zbr
801 * is less than @nm, %NAME_GREATER if it is greater than @nm, and @NOT_ON_MEDIA
802 * if xentry/direntry referred by @zbr does not exist on the media. A negative
803 * error code is returned in case of failure.
805 static int fallible_matches_name(struct ubifs_info *c,
806 struct ubifs_zbranch *zbr,
807 const struct qstr *nm)
809 struct ubifs_dent_node *dent;
812 /* If possible, match against the dent in the leaf node cache */
814 dent = kmalloc(zbr->len, GFP_NOFS);
818 err = fallible_read_node(c, &zbr->key, zbr, dent);
822 /* The node was not present */
826 ubifs_assert(err == 1);
828 err = lnc_add_directly(c, zbr, dent);
834 nlen = le16_to_cpu(dent->nlen);
835 err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
839 else if (nlen < nm->len)
854 * fallible_resolve_collision - resolve a collision even if nodes are missing.
855 * @c: UBIFS file-system description object
857 * @zn: znode is returned here
858 * @n: branch number is passed and returned here
859 * @nm: name of directory entry
860 * @adding: indicates caller is adding a key to the TNC
862 * This is a "fallible" version of the 'resolve_collision()' function which
863 * does not panic if one of the nodes referred to by TNC does not exist on the
864 * media. This may happen when replaying the journal if a deleted node was
865 * Garbage-collected and the commit was not done. A branch that refers to a node
866 * that is not present is called a dangling branch. The following are the return
867 * codes for this function:
868 * o if @nm was found, %1 is returned and @zn and @n are set to the found
870 * o if we are @adding and @nm was not found, %0 is returned;
871 * o if we are not @adding and @nm was not found, but a dangling branch was
872 * found, then %1 is returned and @zn and @n are set to the dangling branch;
873 * o a negative error code is returned in case of failure.
875 static int fallible_resolve_collision(struct ubifs_info *c,
876 const union ubifs_key *key,
877 struct ubifs_znode **zn, int *n,
878 const struct qstr *nm, int adding)
880 struct ubifs_znode *o_znode = NULL, *znode = *zn;
881 int uninitialized_var(o_n), err, cmp, unsure = 0, nn = *n;
883 cmp = fallible_matches_name(c, &znode->zbranch[nn], nm);
884 if (unlikely(cmp < 0))
886 if (cmp == NAME_MATCHES)
888 if (cmp == NOT_ON_MEDIA) {
892 * We are unlucky and hit a dangling branch straight away.
893 * Now we do not really know where to go to find the needed
894 * branch - to the left or to the right. Well, let's try left.
898 unsure = 1; /* Remove a dangling branch wherever it is */
900 if (cmp == NAME_GREATER || unsure) {
903 err = tnc_prev(c, zn, n);
904 if (err == -ENOENT) {
905 ubifs_assert(*n == 0);
911 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
912 /* See comments in 'resolve_collision()' */
913 if (*n == (*zn)->child_cnt - 1) {
914 err = tnc_next(c, zn, n);
916 /* Should be impossible */
922 ubifs_assert(*n == 0);
927 err = fallible_matches_name(c, &(*zn)->zbranch[*n], nm);
930 if (err == NAME_MATCHES)
932 if (err == NOT_ON_MEDIA) {
939 if (err == NAME_LESS)
946 if (cmp == NAME_LESS || unsure) {
951 err = tnc_next(c, &znode, &nn);
956 if (keys_cmp(c, &znode->zbranch[nn].key, key))
958 err = fallible_matches_name(c, &znode->zbranch[nn], nm);
961 if (err == NAME_GREATER)
965 if (err == NAME_MATCHES)
967 if (err == NOT_ON_MEDIA) {
974 /* Never match a dangling branch when adding */
975 if (adding || !o_znode)
978 dbg_mntk(key, "dangling match LEB %d:%d len %d key ",
979 o_znode->zbranch[o_n].lnum, o_znode->zbranch[o_n].offs,
980 o_znode->zbranch[o_n].len);
987 * matches_position - determine if a zbranch matches a given position.
988 * @zbr: zbranch of dent
989 * @lnum: LEB number of dent to match
990 * @offs: offset of dent to match
992 * This function returns %1 if @lnum:@offs matches, and %0 otherwise.
994 static int matches_position(struct ubifs_zbranch *zbr, int lnum, int offs)
996 if (zbr->lnum == lnum && zbr->offs == offs)
1003 * resolve_collision_directly - resolve a collision directly.
1004 * @c: UBIFS file-system description object
1005 * @key: key of directory entry
1006 * @zn: znode is passed and returned here
1007 * @n: zbranch number is passed and returned here
1008 * @lnum: LEB number of dent node to match
1009 * @offs: offset of dent node to match
1011 * This function is used for "hashed" keys to make sure the found directory or
1012 * extended attribute entry node is what was looked for. It is used when the
1013 * flash address of the right node is known (@lnum:@offs) which makes it much
1014 * easier to resolve collisions (no need to read entries and match full
1015 * names). This function returns %1 and sets @zn and @n if the collision is
1016 * resolved, %0 if @lnum:@offs is not found and @zn and @n are set to the
1017 * previous directory entry. Otherwise a negative error code is returned.
1019 static int resolve_collision_directly(struct ubifs_info *c,
1020 const union ubifs_key *key,
1021 struct ubifs_znode **zn, int *n,
1024 struct ubifs_znode *znode;
1029 if (matches_position(&znode->zbranch[nn], lnum, offs))
1034 err = tnc_prev(c, &znode, &nn);
1039 if (keys_cmp(c, &znode->zbranch[nn].key, key))
1041 if (matches_position(&znode->zbranch[nn], lnum, offs)) {
1052 err = tnc_next(c, &znode, &nn);
1057 if (keys_cmp(c, &znode->zbranch[nn].key, key))
1061 if (matches_position(&znode->zbranch[nn], lnum, offs))
1067 * dirty_cow_bottom_up - dirty a znode and its ancestors.
1068 * @c: UBIFS file-system description object
1069 * @znode: znode to dirty
1071 * If we do not have a unique key that resides in a znode, then we cannot
1072 * dirty that znode from the top down (i.e. by using lookup_level0_dirty)
1073 * This function records the path back to the last dirty ancestor, and then
1074 * dirties the znodes on that path.
1076 static struct ubifs_znode *dirty_cow_bottom_up(struct ubifs_info *c,
1077 struct ubifs_znode *znode)
1079 struct ubifs_znode *zp;
1080 int *path = c->bottom_up_buf, p = 0;
1082 ubifs_assert(c->zroot.znode);
1083 ubifs_assert(znode);
1084 if (c->zroot.znode->level > BOTTOM_UP_HEIGHT) {
1085 kfree(c->bottom_up_buf);
1086 c->bottom_up_buf = kmalloc(c->zroot.znode->level * sizeof(int),
1088 if (!c->bottom_up_buf)
1089 return ERR_PTR(-ENOMEM);
1090 path = c->bottom_up_buf;
1092 if (c->zroot.znode->level) {
1093 /* Go up until parent is dirty */
1101 ubifs_assert(p < c->zroot.znode->level);
1103 if (!zp->cnext && ubifs_zn_dirty(znode))
1109 /* Come back down, dirtying as we go */
1111 struct ubifs_zbranch *zbr;
1115 ubifs_assert(path[p - 1] >= 0);
1116 ubifs_assert(path[p - 1] < zp->child_cnt);
1117 zbr = &zp->zbranch[path[--p]];
1118 znode = dirty_cow_znode(c, zbr);
1120 ubifs_assert(znode == c->zroot.znode);
1121 znode = dirty_cow_znode(c, &c->zroot);
1123 if (IS_ERR(znode) || !p)
1125 ubifs_assert(path[p - 1] >= 0);
1126 ubifs_assert(path[p - 1] < znode->child_cnt);
1127 znode = znode->zbranch[path[p - 1]].znode;
1134 * ubifs_lookup_level0 - search for zero-level znode.
1135 * @c: UBIFS file-system description object
1136 * @key: key to lookup
1137 * @zn: znode is returned here
1138 * @n: znode branch slot number is returned here
1140 * This function looks up the TNC tree and search for zero-level znode which
1141 * refers key @key. The found zero-level znode is returned in @zn. There are 3
1143 * o exact match, i.e. the found zero-level znode contains key @key, then %1
1144 * is returned and slot number of the matched branch is stored in @n;
1145 * o not exact match, which means that zero-level znode does not contain
1146 * @key, then %0 is returned and slot number of the closest branch is stored
1148 * o @key is so small that it is even less than the lowest key of the
1149 * leftmost zero-level node, then %0 is returned and %0 is stored in @n.
1151 * Note, when the TNC tree is traversed, some znodes may be absent, then this
1152 * function reads corresponding indexing nodes and inserts them to TNC. In
1153 * case of failure, a negative error code is returned.
1155 int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
1156 struct ubifs_znode **zn, int *n)
1159 struct ubifs_znode *znode;
1160 unsigned long time = get_seconds();
1162 dbg_tnck(key, "search key ");
1163 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
1165 znode = c->zroot.znode;
1166 if (unlikely(!znode)) {
1167 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
1169 return PTR_ERR(znode);
1175 struct ubifs_zbranch *zbr;
1177 exact = ubifs_search_zbranch(c, znode, key, n);
1179 if (znode->level == 0)
1184 zbr = &znode->zbranch[*n];
1192 /* znode is not in TNC cache, load it from the media */
1193 znode = ubifs_load_znode(c, zbr, znode, *n);
1195 return PTR_ERR(znode);
1199 if (exact || !is_hash_key(c, key) || *n != -1) {
1200 dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
1205 * Here is a tricky place. We have not found the key and this is a
1206 * "hashed" key, which may collide. The rest of the code deals with
1207 * situations like this:
1211 * | 3 | 5 | | 6 | 7 | (x)
1213 * Or more a complex example:
1217 * | 1 | 3 | | 5 | 8 |
1219 * | 5 | 5 | | 6 | 7 | (x)
1221 * In the examples, if we are looking for key "5", we may reach nodes
1222 * marked with "(x)". In this case what we have do is to look at the
1223 * left and see if there is "5" key there. If there is, we have to
1226 * Note, this whole situation is possible because we allow to have
1227 * elements which are equivalent to the next key in the parent in the
1228 * children of current znode. For example, this happens if we split a
1229 * znode like this: | 3 | 5 | 5 | 6 | 7 |, which results in something
1233 * | 3 | 5 | | 5 | 6 | 7 |
1235 * And this becomes what is at the first "picture" after key "5" marked
1236 * with "^" is removed. What could be done is we could prohibit
1237 * splitting in the middle of the colliding sequence. Also, when
1238 * removing the leftmost key, we would have to correct the key of the
1239 * parent node, which would introduce additional complications. Namely,
1240 * if we changed the leftmost key of the parent znode, the garbage
1241 * collector would be unable to find it (GC is doing this when GC'ing
1242 * indexing LEBs). Although we already have an additional RB-tree where
1243 * we save such changed znodes (see 'ins_clr_old_idx_znode()') until
1244 * after the commit. But anyway, this does not look easy to implement
1245 * so we did not try this.
1247 err = tnc_prev(c, &znode, n);
1248 if (err == -ENOENT) {
1249 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1253 if (unlikely(err < 0))
1255 if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
1256 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1261 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1267 * lookup_level0_dirty - search for zero-level znode dirtying.
1268 * @c: UBIFS file-system description object
1269 * @key: key to lookup
1270 * @zn: znode is returned here
1271 * @n: znode branch slot number is returned here
1273 * This function looks up the TNC tree and search for zero-level znode which
1274 * refers key @key. The found zero-level znode is returned in @zn. There are 3
1276 * o exact match, i.e. the found zero-level znode contains key @key, then %1
1277 * is returned and slot number of the matched branch is stored in @n;
1278 * o not exact match, which means that zero-level znode does not contain @key
1279 * then %0 is returned and slot number of the closed branch is stored in
1281 * o @key is so small that it is even less than the lowest key of the
1282 * leftmost zero-level node, then %0 is returned and %-1 is stored in @n.
1284 * Additionally all znodes in the path from the root to the located zero-level
1285 * znode are marked as dirty.
1287 * Note, when the TNC tree is traversed, some znodes may be absent, then this
1288 * function reads corresponding indexing nodes and inserts them to TNC. In
1289 * case of failure, a negative error code is returned.
1291 static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key,
1292 struct ubifs_znode **zn, int *n)
1295 struct ubifs_znode *znode;
1296 unsigned long time = get_seconds();
1298 dbg_tnck(key, "search and dirty key ");
1300 znode = c->zroot.znode;
1301 if (unlikely(!znode)) {
1302 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
1304 return PTR_ERR(znode);
1307 znode = dirty_cow_znode(c, &c->zroot);
1309 return PTR_ERR(znode);
1314 struct ubifs_zbranch *zbr;
1316 exact = ubifs_search_zbranch(c, znode, key, n);
1318 if (znode->level == 0)
1323 zbr = &znode->zbranch[*n];
1327 znode = dirty_cow_znode(c, zbr);
1329 return PTR_ERR(znode);
1333 /* znode is not in TNC cache, load it from the media */
1334 znode = ubifs_load_znode(c, zbr, znode, *n);
1336 return PTR_ERR(znode);
1337 znode = dirty_cow_znode(c, zbr);
1339 return PTR_ERR(znode);
1343 if (exact || !is_hash_key(c, key) || *n != -1) {
1344 dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
1349 * See huge comment at 'lookup_level0_dirty()' what is the rest of the
1352 err = tnc_prev(c, &znode, n);
1353 if (err == -ENOENT) {
1355 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1358 if (unlikely(err < 0))
1360 if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
1362 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1366 if (znode->cnext || !ubifs_zn_dirty(znode)) {
1367 znode = dirty_cow_bottom_up(c, znode);
1369 return PTR_ERR(znode);
1372 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1378 * maybe_leb_gced - determine if a LEB may have been garbage collected.
1379 * @c: UBIFS file-system description object
1381 * @gc_seq1: garbage collection sequence number
1383 * This function determines if @lnum may have been garbage collected since
1384 * sequence number @gc_seq1. If it may have been then %1 is returned, otherwise
1387 static int maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1)
1390 int gc_seq2, gced_lnum;
1392 gced_lnum = c->gced_lnum;
1394 gc_seq2 = c->gc_seq;
1395 /* Same seq means no GC */
1396 if (gc_seq1 == gc_seq2)
1398 /* Different by more than 1 means we don't know */
1399 if (gc_seq1 + 1 != gc_seq2)
1402 * We have seen the sequence number has increased by 1. Now we need to
1403 * be sure we read the right LEB number, so read it again.
1406 if (gced_lnum != c->gced_lnum)
1408 /* Finally we can check lnum */
1409 if (gced_lnum == lnum)
1412 /* No garbage collection in the read-only U-Boot implementation */
1418 * ubifs_tnc_locate - look up a file-system node and return it and its location.
1419 * @c: UBIFS file-system description object
1420 * @key: node key to lookup
1421 * @node: the node is returned here
1422 * @lnum: LEB number is returned here
1423 * @offs: offset is returned here
1425 * This function looks up and reads node with key @key. The caller has to make
1426 * sure the @node buffer is large enough to fit the node. Returns zero in case
1427 * of success, %-ENOENT if the node was not found, and a negative error code in
1428 * case of failure. The node location can be returned in @lnum and @offs.
1430 int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key,
1431 void *node, int *lnum, int *offs)
1433 int found, n, err, safely = 0, gc_seq1;
1434 struct ubifs_znode *znode;
1435 struct ubifs_zbranch zbr, *zt;
1438 mutex_lock(&c->tnc_mutex);
1439 found = ubifs_lookup_level0(c, key, &znode, &n);
1443 } else if (found < 0) {
1447 zt = &znode->zbranch[n];
1452 if (is_hash_key(c, key)) {
1454 * In this case the leaf node cache gets used, so we pass the
1455 * address of the zbranch and keep the mutex locked
1457 err = tnc_read_node_nm(c, zt, node);
1461 err = ubifs_tnc_read_node(c, zt, node);
1464 /* Drop the TNC mutex prematurely and race with garbage collection */
1465 zbr = znode->zbranch[n];
1466 gc_seq1 = c->gc_seq;
1467 mutex_unlock(&c->tnc_mutex);
1469 if (ubifs_get_wbuf(c, zbr.lnum)) {
1470 /* We do not GC journal heads */
1471 err = ubifs_tnc_read_node(c, &zbr, node);
1475 err = fallible_read_node(c, key, &zbr, node);
1476 if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) {
1478 * The node may have been GC'ed out from under us so try again
1479 * while keeping the TNC mutex locked.
1487 mutex_unlock(&c->tnc_mutex);
1492 * ubifs_tnc_get_bu_keys - lookup keys for bulk-read.
1493 * @c: UBIFS file-system description object
1494 * @bu: bulk-read parameters and results
1496 * Lookup consecutive data node keys for the same inode that reside
1497 * consecutively in the same LEB. This function returns zero in case of success
1498 * and a negative error code in case of failure.
1500 * Note, if the bulk-read buffer length (@bu->buf_len) is known, this function
1501 * makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares
1502 * maximum possible amount of nodes for bulk-read.
1504 int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)
1506 int n, err = 0, lnum = -1, uninitialized_var(offs);
1507 int uninitialized_var(len);
1508 unsigned int block = key_block(c, &bu->key);
1509 struct ubifs_znode *znode;
1515 mutex_lock(&c->tnc_mutex);
1516 /* Find first key */
1517 err = ubifs_lookup_level0(c, &bu->key, &znode, &n);
1522 len = znode->zbranch[n].len;
1523 /* The buffer must be big enough for at least 1 node */
1524 if (len > bu->buf_len) {
1529 bu->zbranch[bu->cnt++] = znode->zbranch[n];
1531 lnum = znode->zbranch[n].lnum;
1532 offs = ALIGN(znode->zbranch[n].offs + len, 8);
1535 struct ubifs_zbranch *zbr;
1536 union ubifs_key *key;
1537 unsigned int next_block;
1540 err = tnc_next(c, &znode, &n);
1543 zbr = &znode->zbranch[n];
1545 /* See if there is another data key for this file */
1546 if (key_inum(c, key) != key_inum(c, &bu->key) ||
1547 key_type(c, key) != UBIFS_DATA_KEY) {
1552 /* First key found */
1554 offs = ALIGN(zbr->offs + zbr->len, 8);
1556 if (len > bu->buf_len) {
1562 * The data nodes must be in consecutive positions in
1565 if (zbr->lnum != lnum || zbr->offs != offs)
1567 offs += ALIGN(zbr->len, 8);
1568 len = ALIGN(len, 8) + zbr->len;
1569 /* Must not exceed buffer length */
1570 if (len > bu->buf_len)
1573 /* Allow for holes */
1574 next_block = key_block(c, key);
1575 bu->blk_cnt += (next_block - block - 1);
1576 if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
1580 bu->zbranch[bu->cnt++] = *zbr;
1582 /* See if we have room for more */
1583 if (bu->cnt >= UBIFS_MAX_BULK_READ)
1585 if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
1589 if (err == -ENOENT) {
1593 bu->gc_seq = c->gc_seq;
1594 mutex_unlock(&c->tnc_mutex);
1598 * An enormous hole could cause bulk-read to encompass too many
1599 * page cache pages, so limit the number here.
1601 if (bu->blk_cnt > UBIFS_MAX_BULK_READ)
1602 bu->blk_cnt = UBIFS_MAX_BULK_READ;
1604 * Ensure that bulk-read covers a whole number of page cache
1607 if (UBIFS_BLOCKS_PER_PAGE == 1 ||
1608 !(bu->blk_cnt & (UBIFS_BLOCKS_PER_PAGE - 1)))
1611 /* At the end of file we can round up */
1612 bu->blk_cnt += UBIFS_BLOCKS_PER_PAGE - 1;
1615 /* Exclude data nodes that do not make up a whole page cache page */
1616 block = key_block(c, &bu->key) + bu->blk_cnt;
1617 block &= ~(UBIFS_BLOCKS_PER_PAGE - 1);
1619 if (key_block(c, &bu->zbranch[bu->cnt - 1].key) < block)
1627 * read_wbuf - bulk-read from a LEB with a wbuf.
1628 * @wbuf: wbuf that may overlap the read
1629 * @buf: buffer into which to read
1631 * @lnum: LEB number from which to read
1632 * @offs: offset from which to read
1634 * This functions returns %0 on success or a negative error code on failure.
1636 static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum,
1639 const struct ubifs_info *c = wbuf->c;
1642 dbg_io("LEB %d:%d, length %d", lnum, offs, len);
1643 ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
1644 ubifs_assert(!(offs & 7) && offs < c->leb_size);
1645 ubifs_assert(offs + len <= c->leb_size);
1647 spin_lock(&wbuf->lock);
1648 overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
1650 /* We may safely unlock the write-buffer and read the data */
1651 spin_unlock(&wbuf->lock);
1652 return ubifs_leb_read(c, lnum, buf, offs, len, 0);
1655 /* Don't read under wbuf */
1656 rlen = wbuf->offs - offs;
1660 /* Copy the rest from the write-buffer */
1661 memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
1662 spin_unlock(&wbuf->lock);
1665 /* Read everything that goes before write-buffer */
1666 return ubifs_leb_read(c, lnum, buf, offs, rlen, 0);
1672 * validate_data_node - validate data nodes for bulk-read.
1673 * @c: UBIFS file-system description object
1674 * @buf: buffer containing data node to validate
1675 * @zbr: zbranch of data node to validate
1677 * This functions returns %0 on success or a negative error code on failure.
1679 static int validate_data_node(struct ubifs_info *c, void *buf,
1680 struct ubifs_zbranch *zbr)
1682 union ubifs_key key1;
1683 struct ubifs_ch *ch = buf;
1686 if (ch->node_type != UBIFS_DATA_NODE) {
1687 ubifs_err("bad node type (%d but expected %d)",
1688 ch->node_type, UBIFS_DATA_NODE);
1692 err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0, 0);
1694 ubifs_err("expected node type %d", UBIFS_DATA_NODE);
1698 len = le32_to_cpu(ch->len);
1699 if (len != zbr->len) {
1700 ubifs_err("bad node length %d, expected %d", len, zbr->len);
1704 /* Make sure the key of the read node is correct */
1705 key_read(c, buf + UBIFS_KEY_OFFSET, &key1);
1706 if (!keys_eq(c, &zbr->key, &key1)) {
1707 ubifs_err("bad key in node at LEB %d:%d",
1708 zbr->lnum, zbr->offs);
1709 dbg_tnck(&zbr->key, "looked for key ");
1710 dbg_tnck(&key1, "found node's key ");
1719 ubifs_err("bad node at LEB %d:%d", zbr->lnum, zbr->offs);
1720 ubifs_dump_node(c, buf);
1726 * ubifs_tnc_bulk_read - read a number of data nodes in one go.
1727 * @c: UBIFS file-system description object
1728 * @bu: bulk-read parameters and results
1730 * This functions reads and validates the data nodes that were identified by the
1731 * 'ubifs_tnc_get_bu_keys()' function. This functions returns %0 on success,
1732 * -EAGAIN to indicate a race with GC, or another negative error code on
1735 int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu)
1737 int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i;
1738 struct ubifs_wbuf *wbuf;
1741 len = bu->zbranch[bu->cnt - 1].offs;
1742 len += bu->zbranch[bu->cnt - 1].len - offs;
1743 if (len > bu->buf_len) {
1744 ubifs_err("buffer too small %d vs %d", bu->buf_len, len);
1749 wbuf = ubifs_get_wbuf(c, lnum);
1751 err = read_wbuf(wbuf, bu->buf, len, lnum, offs);
1753 err = ubifs_leb_read(c, lnum, bu->buf, offs, len, 0);
1755 /* Check for a race with GC */
1756 if (maybe_leb_gced(c, lnum, bu->gc_seq))
1759 if (err && err != -EBADMSG) {
1760 ubifs_err("failed to read from LEB %d:%d, error %d",
1763 dbg_tnck(&bu->key, "key ");
1767 /* Validate the nodes read */
1769 for (i = 0; i < bu->cnt; i++) {
1770 err = validate_data_node(c, buf, &bu->zbranch[i]);
1773 buf = buf + ALIGN(bu->zbranch[i].len, 8);
1780 * do_lookup_nm- look up a "hashed" node.
1781 * @c: UBIFS file-system description object
1782 * @key: node key to lookup
1783 * @node: the node is returned here
1786 * This function look up and reads a node which contains name hash in the key.
1787 * Since the hash may have collisions, there may be many nodes with the same
1788 * key, so we have to sequentially look to all of them until the needed one is
1789 * found. This function returns zero in case of success, %-ENOENT if the node
1790 * was not found, and a negative error code in case of failure.
1792 static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1793 void *node, const struct qstr *nm)
1796 struct ubifs_znode *znode;
1798 dbg_tnck(key, "name '%.*s' key ", nm->len, nm->name);
1799 mutex_lock(&c->tnc_mutex);
1800 found = ubifs_lookup_level0(c, key, &znode, &n);
1804 } else if (found < 0) {
1809 ubifs_assert(n >= 0);
1811 err = resolve_collision(c, key, &znode, &n, nm);
1812 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
1813 if (unlikely(err < 0))
1820 err = tnc_read_node_nm(c, &znode->zbranch[n], node);
1823 mutex_unlock(&c->tnc_mutex);
1828 * ubifs_tnc_lookup_nm - look up a "hashed" node.
1829 * @c: UBIFS file-system description object
1830 * @key: node key to lookup
1831 * @node: the node is returned here
1834 * This function look up and reads a node which contains name hash in the key.
1835 * Since the hash may have collisions, there may be many nodes with the same
1836 * key, so we have to sequentially look to all of them until the needed one is
1837 * found. This function returns zero in case of success, %-ENOENT if the node
1838 * was not found, and a negative error code in case of failure.
1840 int ubifs_tnc_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1841 void *node, const struct qstr *nm)
1844 const struct ubifs_dent_node *dent = node;
1847 * We assume that in most of the cases there are no name collisions and
1848 * 'ubifs_tnc_lookup()' returns us the right direntry.
1850 err = ubifs_tnc_lookup(c, key, node);
1854 len = le16_to_cpu(dent->nlen);
1855 if (nm->len == len && !memcmp(dent->name, nm->name, len))
1859 * Unluckily, there are hash collisions and we have to iterate over
1860 * them look at each direntry with colliding name hash sequentially.
1862 return do_lookup_nm(c, key, node, nm);
1866 * correct_parent_keys - correct parent znodes' keys.
1867 * @c: UBIFS file-system description object
1868 * @znode: znode to correct parent znodes for
1870 * This is a helper function for 'tnc_insert()'. When the key of the leftmost
1871 * zbranch changes, keys of parent znodes have to be corrected. This helper
1872 * function is called in such situations and corrects the keys if needed.
1874 static void correct_parent_keys(const struct ubifs_info *c,
1875 struct ubifs_znode *znode)
1877 union ubifs_key *key, *key1;
1879 ubifs_assert(znode->parent);
1880 ubifs_assert(znode->iip == 0);
1882 key = &znode->zbranch[0].key;
1883 key1 = &znode->parent->zbranch[0].key;
1885 while (keys_cmp(c, key, key1) < 0) {
1886 key_copy(c, key, key1);
1887 znode = znode->parent;
1889 if (!znode->parent || znode->iip)
1891 key1 = &znode->parent->zbranch[0].key;
1896 * insert_zbranch - insert a zbranch into a znode.
1897 * @znode: znode into which to insert
1898 * @zbr: zbranch to insert
1899 * @n: slot number to insert to
1901 * This is a helper function for 'tnc_insert()'. UBIFS does not allow "gaps" in
1902 * znode's array of zbranches and keeps zbranches consolidated, so when a new
1903 * zbranch has to be inserted to the @znode->zbranches[]' array at the @n-th
1904 * slot, zbranches starting from @n have to be moved right.
1906 static void insert_zbranch(struct ubifs_znode *znode,
1907 const struct ubifs_zbranch *zbr, int n)
1911 ubifs_assert(ubifs_zn_dirty(znode));
1914 for (i = znode->child_cnt; i > n; i--) {
1915 znode->zbranch[i] = znode->zbranch[i - 1];
1916 if (znode->zbranch[i].znode)
1917 znode->zbranch[i].znode->iip = i;
1920 zbr->znode->iip = n;
1922 for (i = znode->child_cnt; i > n; i--)
1923 znode->zbranch[i] = znode->zbranch[i - 1];
1925 znode->zbranch[n] = *zbr;
1926 znode->child_cnt += 1;
1929 * After inserting at slot zero, the lower bound of the key range of
1930 * this znode may have changed. If this znode is subsequently split
1931 * then the upper bound of the key range may change, and furthermore
1932 * it could change to be lower than the original lower bound. If that
1933 * happens, then it will no longer be possible to find this znode in the
1934 * TNC using the key from the index node on flash. That is bad because
1935 * if it is not found, we will assume it is obsolete and may overwrite
1936 * it. Then if there is an unclean unmount, we will start using the
1937 * old index which will be broken.
1939 * So we first mark znodes that have insertions at slot zero, and then
1940 * if they are split we add their lnum/offs to the old_idx tree.
1947 * tnc_insert - insert a node into TNC.
1948 * @c: UBIFS file-system description object
1949 * @znode: znode to insert into
1950 * @zbr: branch to insert
1951 * @n: slot number to insert new zbranch to
1953 * This function inserts a new node described by @zbr into znode @znode. If
1954 * znode does not have a free slot for new zbranch, it is split. Parent znodes
1955 * are splat as well if needed. Returns zero in case of success or a negative
1956 * error code in case of failure.
1958 static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode,
1959 struct ubifs_zbranch *zbr, int n)
1961 struct ubifs_znode *zn, *zi, *zp;
1962 int i, keep, move, appending = 0;
1963 union ubifs_key *key = &zbr->key, *key1;
1965 ubifs_assert(n >= 0 && n <= c->fanout);
1967 /* Implement naive insert for now */
1970 if (znode->child_cnt < c->fanout) {
1971 ubifs_assert(n != c->fanout);
1972 dbg_tnck(key, "inserted at %d level %d, key ", n, znode->level);
1974 insert_zbranch(znode, zbr, n);
1976 /* Ensure parent's key is correct */
1977 if (n == 0 && zp && znode->iip == 0)
1978 correct_parent_keys(c, znode);
1984 * Unfortunately, @znode does not have more empty slots and we have to
1987 dbg_tnck(key, "splitting level %d, key ", znode->level);
1991 * We can no longer be sure of finding this znode by key, so we
1992 * record it in the old_idx tree.
1994 ins_clr_old_idx_znode(c, znode);
1996 zn = kzalloc(c->max_znode_sz, GFP_NOFS);
2000 zn->level = znode->level;
2002 /* Decide where to split */
2003 if (znode->level == 0 && key_type(c, key) == UBIFS_DATA_KEY) {
2004 /* Try not to split consecutive data keys */
2005 if (n == c->fanout) {
2006 key1 = &znode->zbranch[n - 1].key;
2007 if (key_inum(c, key1) == key_inum(c, key) &&
2008 key_type(c, key1) == UBIFS_DATA_KEY)
2012 } else if (appending && n != c->fanout) {
2013 /* Try not to split consecutive data keys */
2016 if (n >= (c->fanout + 1) / 2) {
2017 key1 = &znode->zbranch[0].key;
2018 if (key_inum(c, key1) == key_inum(c, key) &&
2019 key_type(c, key1) == UBIFS_DATA_KEY) {
2020 key1 = &znode->zbranch[n].key;
2021 if (key_inum(c, key1) != key_inum(c, key) ||
2022 key_type(c, key1) != UBIFS_DATA_KEY) {
2024 move = c->fanout - keep;
2036 keep = (c->fanout + 1) / 2;
2037 move = c->fanout - keep;
2041 * Although we don't at present, we could look at the neighbors and see
2042 * if we can move some zbranches there.
2046 /* Insert into existing znode */
2051 /* Insert into new znode */
2056 zbr->znode->parent = zn;
2061 __set_bit(DIRTY_ZNODE, &zn->flags);
2062 atomic_long_inc(&c->dirty_zn_cnt);
2064 zn->child_cnt = move;
2065 znode->child_cnt = keep;
2067 dbg_tnc("moving %d, keeping %d", move, keep);
2070 for (i = 0; i < move; i++) {
2071 zn->zbranch[i] = znode->zbranch[keep + i];
2074 if (zn->zbranch[i].znode) {
2075 zn->zbranch[i].znode->parent = zn;
2076 zn->zbranch[i].znode->iip = i;
2080 /* Insert new key and branch */
2081 dbg_tnck(key, "inserting at %d level %d, key ", n, zn->level);
2083 insert_zbranch(zi, zbr, n);
2085 /* Insert new znode (produced by spitting) into the parent */
2087 if (n == 0 && zi == znode && znode->iip == 0)
2088 correct_parent_keys(c, znode);
2090 /* Locate insertion point */
2093 /* Tail recursion */
2094 zbr->key = zn->zbranch[0].key;
2104 /* We have to split root znode */
2105 dbg_tnc("creating new zroot at level %d", znode->level + 1);
2107 zi = kzalloc(c->max_znode_sz, GFP_NOFS);
2112 zi->level = znode->level + 1;
2114 __set_bit(DIRTY_ZNODE, &zi->flags);
2115 atomic_long_inc(&c->dirty_zn_cnt);
2117 zi->zbranch[0].key = znode->zbranch[0].key;
2118 zi->zbranch[0].znode = znode;
2119 zi->zbranch[0].lnum = c->zroot.lnum;
2120 zi->zbranch[0].offs = c->zroot.offs;
2121 zi->zbranch[0].len = c->zroot.len;
2122 zi->zbranch[1].key = zn->zbranch[0].key;
2123 zi->zbranch[1].znode = zn;
2128 c->zroot.znode = zi;
2139 * ubifs_tnc_add - add a node to TNC.
2140 * @c: UBIFS file-system description object
2142 * @lnum: LEB number of node
2143 * @offs: node offset
2146 * This function adds a node with key @key to TNC. The node may be new or it may
2147 * obsolete some existing one. Returns %0 on success or negative error code on
2150 int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum,
2153 int found, n, err = 0;
2154 struct ubifs_znode *znode;
2156 mutex_lock(&c->tnc_mutex);
2157 dbg_tnck(key, "%d:%d, len %d, key ", lnum, offs, len);
2158 found = lookup_level0_dirty(c, key, &znode, &n);
2160 struct ubifs_zbranch zbr;
2166 key_copy(c, key, &zbr.key);
2167 err = tnc_insert(c, znode, &zbr, n + 1);
2168 } else if (found == 1) {
2169 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2172 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2179 err = dbg_check_tnc(c, 0);
2180 mutex_unlock(&c->tnc_mutex);
2186 * ubifs_tnc_replace - replace a node in the TNC only if the old node is found.
2187 * @c: UBIFS file-system description object
2189 * @old_lnum: LEB number of old node
2190 * @old_offs: old node offset
2191 * @lnum: LEB number of node
2192 * @offs: node offset
2195 * This function replaces a node with key @key in the TNC only if the old node
2196 * is found. This function is called by garbage collection when node are moved.
2197 * Returns %0 on success or negative error code on failure.
2199 int ubifs_tnc_replace(struct ubifs_info *c, const union ubifs_key *key,
2200 int old_lnum, int old_offs, int lnum, int offs, int len)
2202 int found, n, err = 0;
2203 struct ubifs_znode *znode;
2205 mutex_lock(&c->tnc_mutex);
2206 dbg_tnck(key, "old LEB %d:%d, new LEB %d:%d, len %d, key ", old_lnum,
2207 old_offs, lnum, offs, len);
2208 found = lookup_level0_dirty(c, key, &znode, &n);
2215 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2218 if (zbr->lnum == old_lnum && zbr->offs == old_offs) {
2220 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2227 } else if (is_hash_key(c, key)) {
2228 found = resolve_collision_directly(c, key, &znode, &n,
2229 old_lnum, old_offs);
2230 dbg_tnc("rc returned %d, znode %p, n %d, LEB %d:%d",
2231 found, znode, n, old_lnum, old_offs);
2238 /* Ensure the znode is dirtied */
2239 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2240 znode = dirty_cow_bottom_up(c, znode);
2241 if (IS_ERR(znode)) {
2242 err = PTR_ERR(znode);
2246 zbr = &znode->zbranch[n];
2248 err = ubifs_add_dirt(c, zbr->lnum,
2260 err = ubifs_add_dirt(c, lnum, len);
2263 err = dbg_check_tnc(c, 0);
2266 mutex_unlock(&c->tnc_mutex);
2271 * ubifs_tnc_add_nm - add a "hashed" node to TNC.
2272 * @c: UBIFS file-system description object
2274 * @lnum: LEB number of node
2275 * @offs: node offset
2279 * This is the same as 'ubifs_tnc_add()' but it should be used with keys which
2280 * may have collisions, like directory entry keys.
2282 int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
2283 int lnum, int offs, int len, const struct qstr *nm)
2285 int found, n, err = 0;
2286 struct ubifs_znode *znode;
2288 mutex_lock(&c->tnc_mutex);
2289 dbg_tnck(key, "LEB %d:%d, name '%.*s', key ",
2290 lnum, offs, nm->len, nm->name);
2291 found = lookup_level0_dirty(c, key, &znode, &n);
2299 found = fallible_resolve_collision(c, key, &znode, &n,
2302 found = resolve_collision(c, key, &znode, &n, nm);
2303 dbg_tnc("rc returned %d, znode %p, n %d", found, znode, n);
2309 /* Ensure the znode is dirtied */
2310 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2311 znode = dirty_cow_bottom_up(c, znode);
2312 if (IS_ERR(znode)) {
2313 err = PTR_ERR(znode);
2319 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2322 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2331 struct ubifs_zbranch zbr;
2337 key_copy(c, key, &zbr.key);
2338 err = tnc_insert(c, znode, &zbr, n + 1);
2343 * We did not find it in the index so there may be a
2344 * dangling branch still in the index. So we remove it
2345 * by passing 'ubifs_tnc_remove_nm()' the same key but
2346 * an unmatchable name.
2348 struct qstr noname = { .name = "" };
2350 err = dbg_check_tnc(c, 0);
2351 mutex_unlock(&c->tnc_mutex);
2354 return ubifs_tnc_remove_nm(c, key, &noname);
2360 err = dbg_check_tnc(c, 0);
2361 mutex_unlock(&c->tnc_mutex);
2366 * tnc_delete - delete a znode form TNC.
2367 * @c: UBIFS file-system description object
2368 * @znode: znode to delete from
2369 * @n: zbranch slot number to delete
2371 * This function deletes a leaf node from @n-th slot of @znode. Returns zero in
2372 * case of success and a negative error code in case of failure.
2374 static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n)
2376 struct ubifs_zbranch *zbr;
2377 struct ubifs_znode *zp;
2380 /* Delete without merge for now */
2381 ubifs_assert(znode->level == 0);
2382 ubifs_assert(n >= 0 && n < c->fanout);
2383 dbg_tnck(&znode->zbranch[n].key, "deleting key ");
2385 zbr = &znode->zbranch[n];
2388 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2390 ubifs_dump_znode(c, znode);
2394 /* We do not "gap" zbranch slots */
2395 for (i = n; i < znode->child_cnt - 1; i++)
2396 znode->zbranch[i] = znode->zbranch[i + 1];
2397 znode->child_cnt -= 1;
2399 if (znode->child_cnt > 0)
2403 * This was the last zbranch, we have to delete this znode from the
2408 ubifs_assert(!ubifs_zn_obsolete(znode));
2409 ubifs_assert(ubifs_zn_dirty(znode));
2414 atomic_long_dec(&c->dirty_zn_cnt);
2416 err = insert_old_idx_znode(c, znode);
2421 __set_bit(OBSOLETE_ZNODE, &znode->flags);
2422 atomic_long_inc(&c->clean_zn_cnt);
2423 atomic_long_inc(&ubifs_clean_zn_cnt);
2427 } while (znode->child_cnt == 1); /* while removing last child */
2429 /* Remove from znode, entry n - 1 */
2430 znode->child_cnt -= 1;
2431 ubifs_assert(znode->level != 0);
2432 for (i = n; i < znode->child_cnt; i++) {
2433 znode->zbranch[i] = znode->zbranch[i + 1];
2434 if (znode->zbranch[i].znode)
2435 znode->zbranch[i].znode->iip = i;
2439 * If this is the root and it has only 1 child then
2440 * collapse the tree.
2442 if (!znode->parent) {
2443 while (znode->child_cnt == 1 && znode->level != 0) {
2445 zbr = &znode->zbranch[0];
2446 znode = get_znode(c, znode, 0);
2448 return PTR_ERR(znode);
2449 znode = dirty_cow_znode(c, zbr);
2451 return PTR_ERR(znode);
2452 znode->parent = NULL;
2455 err = insert_old_idx(c, c->zroot.lnum,
2460 c->zroot.lnum = zbr->lnum;
2461 c->zroot.offs = zbr->offs;
2462 c->zroot.len = zbr->len;
2463 c->zroot.znode = znode;
2464 ubifs_assert(!ubifs_zn_obsolete(zp));
2465 ubifs_assert(ubifs_zn_dirty(zp));
2466 atomic_long_dec(&c->dirty_zn_cnt);
2469 __set_bit(OBSOLETE_ZNODE, &zp->flags);
2470 atomic_long_inc(&c->clean_zn_cnt);
2471 atomic_long_inc(&ubifs_clean_zn_cnt);
2481 * ubifs_tnc_remove - remove an index entry of a node.
2482 * @c: UBIFS file-system description object
2485 * Returns %0 on success or negative error code on failure.
2487 int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key)
2489 int found, n, err = 0;
2490 struct ubifs_znode *znode;
2492 mutex_lock(&c->tnc_mutex);
2493 dbg_tnck(key, "key ");
2494 found = lookup_level0_dirty(c, key, &znode, &n);
2500 err = tnc_delete(c, znode, n);
2502 err = dbg_check_tnc(c, 0);
2505 mutex_unlock(&c->tnc_mutex);
2510 * ubifs_tnc_remove_nm - remove an index entry for a "hashed" node.
2511 * @c: UBIFS file-system description object
2513 * @nm: directory entry name
2515 * Returns %0 on success or negative error code on failure.
2517 int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
2518 const struct qstr *nm)
2521 struct ubifs_znode *znode;
2523 mutex_lock(&c->tnc_mutex);
2524 dbg_tnck(key, "%.*s, key ", nm->len, nm->name);
2525 err = lookup_level0_dirty(c, key, &znode, &n);
2531 err = fallible_resolve_collision(c, key, &znode, &n,
2534 err = resolve_collision(c, key, &znode, &n, nm);
2535 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
2539 /* Ensure the znode is dirtied */
2540 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2541 znode = dirty_cow_bottom_up(c, znode);
2542 if (IS_ERR(znode)) {
2543 err = PTR_ERR(znode);
2547 err = tnc_delete(c, znode, n);
2553 err = dbg_check_tnc(c, 0);
2554 mutex_unlock(&c->tnc_mutex);
2559 * key_in_range - determine if a key falls within a range of keys.
2560 * @c: UBIFS file-system description object
2561 * @key: key to check
2562 * @from_key: lowest key in range
2563 * @to_key: highest key in range
2565 * This function returns %1 if the key is in range and %0 otherwise.
2567 static int key_in_range(struct ubifs_info *c, union ubifs_key *key,
2568 union ubifs_key *from_key, union ubifs_key *to_key)
2570 if (keys_cmp(c, key, from_key) < 0)
2572 if (keys_cmp(c, key, to_key) > 0)
2578 * ubifs_tnc_remove_range - remove index entries in range.
2579 * @c: UBIFS file-system description object
2580 * @from_key: lowest key to remove
2581 * @to_key: highest key to remove
2583 * This function removes index entries starting at @from_key and ending at
2584 * @to_key. This function returns zero in case of success and a negative error
2585 * code in case of failure.
2587 int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key,
2588 union ubifs_key *to_key)
2590 int i, n, k, err = 0;
2591 struct ubifs_znode *znode;
2592 union ubifs_key *key;
2594 mutex_lock(&c->tnc_mutex);
2596 /* Find first level 0 znode that contains keys to remove */
2597 err = ubifs_lookup_level0(c, from_key, &znode, &n);
2604 err = tnc_next(c, &znode, &n);
2605 if (err == -ENOENT) {
2611 key = &znode->zbranch[n].key;
2612 if (!key_in_range(c, key, from_key, to_key)) {
2618 /* Ensure the znode is dirtied */
2619 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2620 znode = dirty_cow_bottom_up(c, znode);
2621 if (IS_ERR(znode)) {
2622 err = PTR_ERR(znode);
2627 /* Remove all keys in range except the first */
2628 for (i = n + 1, k = 0; i < znode->child_cnt; i++, k++) {
2629 key = &znode->zbranch[i].key;
2630 if (!key_in_range(c, key, from_key, to_key))
2632 lnc_free(&znode->zbranch[i]);
2633 err = ubifs_add_dirt(c, znode->zbranch[i].lnum,
2634 znode->zbranch[i].len);
2636 ubifs_dump_znode(c, znode);
2639 dbg_tnck(key, "removing key ");
2642 for (i = n + 1 + k; i < znode->child_cnt; i++)
2643 znode->zbranch[i - k] = znode->zbranch[i];
2644 znode->child_cnt -= k;
2647 /* Now delete the first */
2648 err = tnc_delete(c, znode, n);
2655 err = dbg_check_tnc(c, 0);
2656 mutex_unlock(&c->tnc_mutex);
2661 * ubifs_tnc_remove_ino - remove an inode from TNC.
2662 * @c: UBIFS file-system description object
2663 * @inum: inode number to remove
2665 * This function remove inode @inum and all the extended attributes associated
2666 * with the anode from TNC and returns zero in case of success or a negative
2667 * error code in case of failure.
2669 int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum)
2671 union ubifs_key key1, key2;
2672 struct ubifs_dent_node *xent, *pxent = NULL;
2673 struct qstr nm = { .name = NULL };
2675 dbg_tnc("ino %lu", (unsigned long)inum);
2678 * Walk all extended attribute entries and remove them together with
2679 * corresponding extended attribute inodes.
2681 lowest_xent_key(c, &key1, inum);
2686 xent = ubifs_tnc_next_ent(c, &key1, &nm);
2688 err = PTR_ERR(xent);
2694 xattr_inum = le64_to_cpu(xent->inum);
2695 dbg_tnc("xent '%s', ino %lu", xent->name,
2696 (unsigned long)xattr_inum);
2698 nm.name = xent->name;
2699 nm.len = le16_to_cpu(xent->nlen);
2700 err = ubifs_tnc_remove_nm(c, &key1, &nm);
2706 lowest_ino_key(c, &key1, xattr_inum);
2707 highest_ino_key(c, &key2, xattr_inum);
2708 err = ubifs_tnc_remove_range(c, &key1, &key2);
2716 key_read(c, &xent->key, &key1);
2720 lowest_ino_key(c, &key1, inum);
2721 highest_ino_key(c, &key2, inum);
2723 return ubifs_tnc_remove_range(c, &key1, &key2);
2727 * ubifs_tnc_next_ent - walk directory or extended attribute entries.
2728 * @c: UBIFS file-system description object
2729 * @key: key of last entry
2730 * @nm: name of last entry found or %NULL
2732 * This function finds and reads the next directory or extended attribute entry
2733 * after the given key (@key) if there is one. @nm is used to resolve
2736 * If the name of the current entry is not known and only the key is known,
2737 * @nm->name has to be %NULL. In this case the semantics of this function is a
2738 * little bit different and it returns the entry corresponding to this key, not
2739 * the next one. If the key was not found, the closest "right" entry is
2742 * If the fist entry has to be found, @key has to contain the lowest possible
2743 * key value for this inode and @name has to be %NULL.
2745 * This function returns the found directory or extended attribute entry node
2746 * in case of success, %-ENOENT is returned if no entry was found, and a
2747 * negative error code is returned in case of failure.
2749 struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c,
2750 union ubifs_key *key,
2751 const struct qstr *nm)
2753 int n, err, type = key_type(c, key);
2754 struct ubifs_znode *znode;
2755 struct ubifs_dent_node *dent;
2756 struct ubifs_zbranch *zbr;
2757 union ubifs_key *dkey;
2759 dbg_tnck(key, "%s ", nm->name ? (char *)nm->name : "(lowest)");
2760 ubifs_assert(is_hash_key(c, key));
2762 mutex_lock(&c->tnc_mutex);
2763 err = ubifs_lookup_level0(c, key, &znode, &n);
2764 if (unlikely(err < 0))
2769 /* Handle collisions */
2770 err = resolve_collision(c, key, &znode, &n, nm);
2771 dbg_tnc("rc returned %d, znode %p, n %d",
2773 if (unlikely(err < 0))
2777 /* Now find next entry */
2778 err = tnc_next(c, &znode, &n);
2783 * The full name of the entry was not given, in which case the
2784 * behavior of this function is a little different and it
2785 * returns current entry, not the next one.
2789 * However, the given key does not exist in the TNC
2790 * tree and @znode/@n variables contain the closest
2791 * "preceding" element. Switch to the next one.
2793 err = tnc_next(c, &znode, &n);
2799 zbr = &znode->zbranch[n];
2800 dent = kmalloc(zbr->len, GFP_NOFS);
2801 if (unlikely(!dent)) {
2807 * The above 'tnc_next()' call could lead us to the next inode, check
2811 if (key_inum(c, dkey) != key_inum(c, key) ||
2812 key_type(c, dkey) != type) {
2817 err = tnc_read_node_nm(c, zbr, dent);
2821 mutex_unlock(&c->tnc_mutex);
2827 mutex_unlock(&c->tnc_mutex);
2828 return ERR_PTR(err);
2833 * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit.
2834 * @c: UBIFS file-system description object
2836 * Destroy left-over obsolete znodes from a failed commit.
2838 static void tnc_destroy_cnext(struct ubifs_info *c)
2840 struct ubifs_znode *cnext;
2844 ubifs_assert(c->cmt_state == COMMIT_BROKEN);
2847 struct ubifs_znode *znode = cnext;
2849 cnext = cnext->cnext;
2850 if (ubifs_zn_obsolete(znode))
2852 } while (cnext && cnext != c->cnext);
2856 * ubifs_tnc_close - close TNC subsystem and free all related resources.
2857 * @c: UBIFS file-system description object
2859 void ubifs_tnc_close(struct ubifs_info *c)
2861 tnc_destroy_cnext(c);
2862 if (c->zroot.znode) {
2865 ubifs_destroy_tnc_subtree(c->zroot.znode);
2866 n = atomic_long_read(&c->clean_zn_cnt);
2867 atomic_long_sub(n, &ubifs_clean_zn_cnt);
2876 * left_znode - get the znode to the left.
2877 * @c: UBIFS file-system description object
2880 * This function returns a pointer to the znode to the left of @znode or NULL if
2881 * there is not one. A negative error code is returned on failure.
2883 static struct ubifs_znode *left_znode(struct ubifs_info *c,
2884 struct ubifs_znode *znode)
2886 int level = znode->level;
2889 int n = znode->iip - 1;
2891 /* Go up until we can go left */
2892 znode = znode->parent;
2896 /* Now go down the rightmost branch to 'level' */
2897 znode = get_znode(c, znode, n);
2900 while (znode->level != level) {
2901 n = znode->child_cnt - 1;
2902 znode = get_znode(c, znode, n);
2913 * right_znode - get the znode to the right.
2914 * @c: UBIFS file-system description object
2917 * This function returns a pointer to the znode to the right of @znode or NULL
2918 * if there is not one. A negative error code is returned on failure.
2920 static struct ubifs_znode *right_znode(struct ubifs_info *c,
2921 struct ubifs_znode *znode)
2923 int level = znode->level;
2926 int n = znode->iip + 1;
2928 /* Go up until we can go right */
2929 znode = znode->parent;
2932 if (n < znode->child_cnt) {
2933 /* Now go down the leftmost branch to 'level' */
2934 znode = get_znode(c, znode, n);
2937 while (znode->level != level) {
2938 znode = get_znode(c, znode, 0);
2949 * lookup_znode - find a particular indexing node from TNC.
2950 * @c: UBIFS file-system description object
2951 * @key: index node key to lookup
2952 * @level: index node level
2953 * @lnum: index node LEB number
2954 * @offs: index node offset
2956 * This function searches an indexing node by its first key @key and its
2957 * address @lnum:@offs. It looks up the indexing tree by pulling all indexing
2958 * nodes it traverses to TNC. This function is called for indexing nodes which
2959 * were found on the media by scanning, for example when garbage-collecting or
2960 * when doing in-the-gaps commit. This means that the indexing node which is
2961 * looked for does not have to have exactly the same leftmost key @key, because
2962 * the leftmost key may have been changed, in which case TNC will contain a
2963 * dirty znode which still refers the same @lnum:@offs. This function is clever
2964 * enough to recognize such indexing nodes.
2966 * Note, if a znode was deleted or changed too much, then this function will
2967 * not find it. For situations like this UBIFS has the old index RB-tree
2968 * (indexed by @lnum:@offs).
2970 * This function returns a pointer to the znode found or %NULL if it is not
2971 * found. A negative error code is returned on failure.
2973 static struct ubifs_znode *lookup_znode(struct ubifs_info *c,
2974 union ubifs_key *key, int level,
2977 struct ubifs_znode *znode, *zn;
2980 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
2983 * The arguments have probably been read off flash, so don't assume
2987 return ERR_PTR(-EINVAL);
2989 /* Get the root znode */
2990 znode = c->zroot.znode;
2992 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
2996 /* Check if it is the one we are looking for */
2997 if (c->zroot.lnum == lnum && c->zroot.offs == offs)
2999 /* Descend to the parent level i.e. (level + 1) */
3000 if (level >= znode->level)
3003 ubifs_search_zbranch(c, znode, key, &n);
3006 * We reached a znode where the leftmost key is greater
3007 * than the key we are searching for. This is the same
3008 * situation as the one described in a huge comment at
3009 * the end of the 'ubifs_lookup_level0()' function. And
3010 * for exactly the same reasons we have to try to look
3011 * left before giving up.
3013 znode = left_znode(c, znode);
3018 ubifs_search_zbranch(c, znode, key, &n);
3019 ubifs_assert(n >= 0);
3021 if (znode->level == level + 1)
3023 znode = get_znode(c, znode, n);
3027 /* Check if the child is the one we are looking for */
3028 if (znode->zbranch[n].lnum == lnum && znode->zbranch[n].offs == offs)
3029 return get_znode(c, znode, n);
3030 /* If the key is unique, there is nowhere else to look */
3031 if (!is_hash_key(c, key))
3034 * The key is not unique and so may be also in the znodes to either
3041 /* Move one branch to the left */
3045 znode = left_znode(c, znode);
3050 n = znode->child_cnt - 1;
3053 if (znode->zbranch[n].lnum == lnum &&
3054 znode->zbranch[n].offs == offs)
3055 return get_znode(c, znode, n);
3056 /* Stop if the key is less than the one we are looking for */
3057 if (keys_cmp(c, &znode->zbranch[n].key, key) < 0)
3060 /* Back to the middle */
3065 /* Move one branch to the right */
3066 if (++n >= znode->child_cnt) {
3067 znode = right_znode(c, znode);
3075 if (znode->zbranch[n].lnum == lnum &&
3076 znode->zbranch[n].offs == offs)
3077 return get_znode(c, znode, n);
3078 /* Stop if the key is greater than the one we are looking for */
3079 if (keys_cmp(c, &znode->zbranch[n].key, key) > 0)
3086 * is_idx_node_in_tnc - determine if an index node is in the TNC.
3087 * @c: UBIFS file-system description object
3088 * @key: key of index node
3089 * @level: index node level
3090 * @lnum: LEB number of index node
3091 * @offs: offset of index node
3093 * This function returns %0 if the index node is not referred to in the TNC, %1
3094 * if the index node is referred to in the TNC and the corresponding znode is
3095 * dirty, %2 if an index node is referred to in the TNC and the corresponding
3096 * znode is clean, and a negative error code in case of failure.
3098 * Note, the @key argument has to be the key of the first child. Also note,
3099 * this function relies on the fact that 0:0 is never a valid LEB number and
3100 * offset for a main-area node.
3102 int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level,
3105 struct ubifs_znode *znode;
3107 znode = lookup_znode(c, key, level, lnum, offs);
3111 return PTR_ERR(znode);
3113 return ubifs_zn_dirty(znode) ? 1 : 2;
3117 * is_leaf_node_in_tnc - determine if a non-indexing not is in the TNC.
3118 * @c: UBIFS file-system description object
3120 * @lnum: node LEB number
3121 * @offs: node offset
3123 * This function returns %1 if the node is referred to in the TNC, %0 if it is
3124 * not, and a negative error code in case of failure.
3126 * Note, this function relies on the fact that 0:0 is never a valid LEB number
3127 * and offset for a main-area node.
3129 static int is_leaf_node_in_tnc(struct ubifs_info *c, union ubifs_key *key,
3132 struct ubifs_zbranch *zbr;
3133 struct ubifs_znode *znode, *zn;
3134 int n, found, err, nn;
3135 const int unique = !is_hash_key(c, key);
3137 found = ubifs_lookup_level0(c, key, &znode, &n);
3139 return found; /* Error code */
3142 zbr = &znode->zbranch[n];
3143 if (lnum == zbr->lnum && offs == zbr->offs)
3144 return 1; /* Found it */
3148 * Because the key is not unique, we have to look left
3155 err = tnc_prev(c, &znode, &n);
3160 if (keys_cmp(c, key, &znode->zbranch[n].key))
3162 zbr = &znode->zbranch[n];
3163 if (lnum == zbr->lnum && offs == zbr->offs)
3164 return 1; /* Found it */
3170 err = tnc_next(c, &znode, &n);
3176 if (keys_cmp(c, key, &znode->zbranch[n].key))
3178 zbr = &znode->zbranch[n];
3179 if (lnum == zbr->lnum && offs == zbr->offs)
3180 return 1; /* Found it */
3186 * ubifs_tnc_has_node - determine whether a node is in the TNC.
3187 * @c: UBIFS file-system description object
3189 * @level: index node level (if it is an index node)
3190 * @lnum: node LEB number
3191 * @offs: node offset
3192 * @is_idx: non-zero if the node is an index node
3194 * This function returns %1 if the node is in the TNC, %0 if it is not, and a
3195 * negative error code in case of failure. For index nodes, @key has to be the
3196 * key of the first child. An index node is considered to be in the TNC only if
3197 * the corresponding znode is clean or has not been loaded.
3199 int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level,
3200 int lnum, int offs, int is_idx)
3204 mutex_lock(&c->tnc_mutex);
3206 err = is_idx_node_in_tnc(c, key, level, lnum, offs);
3210 /* The index node was found but it was dirty */
3213 /* The index node was found and it was clean */
3218 err = is_leaf_node_in_tnc(c, key, lnum, offs);
3221 mutex_unlock(&c->tnc_mutex);
3226 * ubifs_dirty_idx_node - dirty an index node.
3227 * @c: UBIFS file-system description object
3228 * @key: index node key
3229 * @level: index node level
3230 * @lnum: index node LEB number
3231 * @offs: index node offset
3233 * This function loads and dirties an index node so that it can be garbage
3234 * collected. The @key argument has to be the key of the first child. This
3235 * function relies on the fact that 0:0 is never a valid LEB number and offset
3236 * for a main-area node. Returns %0 on success and a negative error code on
3239 int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level,
3242 struct ubifs_znode *znode;
3245 mutex_lock(&c->tnc_mutex);
3246 znode = lookup_znode(c, key, level, lnum, offs);
3249 if (IS_ERR(znode)) {
3250 err = PTR_ERR(znode);
3253 znode = dirty_cow_bottom_up(c, znode);
3254 if (IS_ERR(znode)) {
3255 err = PTR_ERR(znode);
3260 mutex_unlock(&c->tnc_mutex);
3265 * dbg_check_inode_size - check if inode size is correct.
3266 * @c: UBIFS file-system description object
3267 * @inum: inode number
3270 * This function makes sure that the inode size (@size) is correct and it does
3271 * not have any pages beyond @size. Returns zero if the inode is OK, %-EINVAL
3272 * if it has a data page beyond @size, and other negative error code in case of
3275 int dbg_check_inode_size(struct ubifs_info *c, const struct inode *inode,
3279 union ubifs_key from_key, to_key, *key;
3280 struct ubifs_znode *znode;
3283 if (!S_ISREG(inode->i_mode))
3285 if (!dbg_is_chk_gen(c))
3288 block = (size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT;
3289 data_key_init(c, &from_key, inode->i_ino, block);
3290 highest_data_key(c, &to_key, inode->i_ino);
3292 mutex_lock(&c->tnc_mutex);
3293 err = ubifs_lookup_level0(c, &from_key, &znode, &n);
3303 err = tnc_next(c, &znode, &n);
3304 if (err == -ENOENT) {
3311 ubifs_assert(err == 0);
3312 key = &znode->zbranch[n].key;
3313 if (!key_in_range(c, key, &from_key, &to_key))
3317 block = key_block(c, key);
3318 ubifs_err("inode %lu has size %lld, but there are data at offset %lld",
3319 (unsigned long)inode->i_ino, size,
3320 ((loff_t)block) << UBIFS_BLOCK_SHIFT);
3321 mutex_unlock(&c->tnc_mutex);
3322 ubifs_dump_inode(c, inode);
3327 mutex_unlock(&c->tnc_mutex);