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1/*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * Authors: Adrian Hunter
20 * Artem Bityutskiy (Битюцкий Артём)
21 */
22
23/*
24 * This file implements TNC (Tree Node Cache) which caches indexing nodes of
25 * the UBIFS B-tree.
26 *
27 * At the moment the locking rules of the TNC tree are quite simple and
28 * straightforward. We just have a mutex and lock it when we traverse the
29 * tree. If a znode is not in memory, we read it from flash while still having
30 * the mutex locked.
31 */
32
33#include <linux/crc32.h>
34#include <linux/slab.h>
35#include "ubifs.h"
36
37/*
38 * Returned codes of 'matches_name()' and 'fallible_matches_name()' functions.
39 * @NAME_LESS: name corresponding to the first argument is less than second
40 * @NAME_MATCHES: names match
41 * @NAME_GREATER: name corresponding to the second argument is greater than
42 * first
43 * @NOT_ON_MEDIA: node referred by zbranch does not exist on the media
44 *
45 * These constants were introduce to improve readability.
46 */
47enum {
48 NAME_LESS = 0,
49 NAME_MATCHES = 1,
50 NAME_GREATER = 2,
51 NOT_ON_MEDIA = 3,
52};
53
54/**
55 * insert_old_idx - record an index node obsoleted since the last commit start.
56 * @c: UBIFS file-system description object
57 * @lnum: LEB number of obsoleted index node
58 * @offs: offset of obsoleted index node
59 *
60 * Returns %0 on success, and a negative error code on failure.
61 *
62 * For recovery, there must always be a complete intact version of the index on
63 * flash at all times. That is called the "old index". It is the index as at the
64 * time of the last successful commit. Many of the index nodes in the old index
65 * may be dirty, but they must not be erased until the next successful commit
66 * (at which point that index becomes the old index).
67 *
68 * That means that the garbage collection and the in-the-gaps method of
69 * committing must be able to determine if an index node is in the old index.
70 * Most of the old index nodes can be found by looking up the TNC using the
71 * 'lookup_znode()' function. However, some of the old index nodes may have
72 * been deleted from the current index or may have been changed so much that
73 * they cannot be easily found. In those cases, an entry is added to an RB-tree.
74 * That is what this function does. The RB-tree is ordered by LEB number and
75 * offset because they uniquely identify the old index node.
76 */
77static int insert_old_idx(struct ubifs_info *c, int lnum, int offs)
78{
79 struct ubifs_old_idx *old_idx, *o;
80 struct rb_node **p, *parent = NULL;
81
82 old_idx = kmalloc(sizeof(struct ubifs_old_idx), GFP_NOFS);
83 if (unlikely(!old_idx))
84 return -ENOMEM;
85 old_idx->lnum = lnum;
86 old_idx->offs = offs;
87
88 p = &c->old_idx.rb_node;
89 while (*p) {
90 parent = *p;
91 o = rb_entry(parent, struct ubifs_old_idx, rb);
92 if (lnum < o->lnum)
93 p = &(*p)->rb_left;
94 else if (lnum > o->lnum)
95 p = &(*p)->rb_right;
96 else if (offs < o->offs)
97 p = &(*p)->rb_left;
98 else if (offs > o->offs)
99 p = &(*p)->rb_right;
100 else {
101 ubifs_err("old idx added twice!");
102 kfree(old_idx);
103 return 0;
104 }
105 }
106 rb_link_node(&old_idx->rb, parent, p);
107 rb_insert_color(&old_idx->rb, &c->old_idx);
108 return 0;
109}
110
111/**
112 * insert_old_idx_znode - record a znode obsoleted since last commit start.
113 * @c: UBIFS file-system description object
114 * @znode: znode of obsoleted index node
115 *
116 * Returns %0 on success, and a negative error code on failure.
117 */
118int insert_old_idx_znode(struct ubifs_info *c, struct ubifs_znode *znode)
119{
120 if (znode->parent) {
121 struct ubifs_zbranch *zbr;
122
123 zbr = &znode->parent->zbranch[znode->iip];
124 if (zbr->len)
125 return insert_old_idx(c, zbr->lnum, zbr->offs);
126 } else
127 if (c->zroot.len)
128 return insert_old_idx(c, c->zroot.lnum,
129 c->zroot.offs);
130 return 0;
131}
132
133/**
134 * ins_clr_old_idx_znode - record a znode obsoleted since last commit start.
135 * @c: UBIFS file-system description object
136 * @znode: znode of obsoleted index node
137 *
138 * Returns %0 on success, and a negative error code on failure.
139 */
140static int ins_clr_old_idx_znode(struct ubifs_info *c,
141 struct ubifs_znode *znode)
142{
143 int err;
144
145 if (znode->parent) {
146 struct ubifs_zbranch *zbr;
147
148 zbr = &znode->parent->zbranch[znode->iip];
149 if (zbr->len) {
150 err = insert_old_idx(c, zbr->lnum, zbr->offs);
151 if (err)
152 return err;
153 zbr->lnum = 0;
154 zbr->offs = 0;
155 zbr->len = 0;
156 }
157 } else
158 if (c->zroot.len) {
159 err = insert_old_idx(c, c->zroot.lnum, c->zroot.offs);
160 if (err)
161 return err;
162 c->zroot.lnum = 0;
163 c->zroot.offs = 0;
164 c->zroot.len = 0;
165 }
166 return 0;
167}
168
169/**
170 * destroy_old_idx - destroy the old_idx RB-tree.
171 * @c: UBIFS file-system description object
172 *
173 * During start commit, the old_idx RB-tree is used to avoid overwriting index
174 * nodes that were in the index last commit but have since been deleted. This
175 * is necessary for recovery i.e. the old index must be kept intact until the
176 * new index is successfully written. The old-idx RB-tree is used for the
177 * in-the-gaps method of writing index nodes and is destroyed every commit.
178 */
179void destroy_old_idx(struct ubifs_info *c)
180{
181 struct rb_node *this = c->old_idx.rb_node;
182 struct ubifs_old_idx *old_idx;
183
184 while (this) {
185 if (this->rb_left) {
186 this = this->rb_left;
187 continue;
188 } else if (this->rb_right) {
189 this = this->rb_right;
190 continue;
191 }
192 old_idx = rb_entry(this, struct ubifs_old_idx, rb);
193 this = rb_parent(this);
194 if (this) {
195 if (this->rb_left == &old_idx->rb)
196 this->rb_left = NULL;
197 else
198 this->rb_right = NULL;
199 }
200 kfree(old_idx);
201 }
202 c->old_idx = RB_ROOT;
203}
204
205/**
206 * copy_znode - copy a dirty znode.
207 * @c: UBIFS file-system description object
208 * @znode: znode to copy
209 *
210 * A dirty znode being committed may not be changed, so it is copied.
211 */
212static struct ubifs_znode *copy_znode(struct ubifs_info *c,
213 struct ubifs_znode *znode)
214{
215 struct ubifs_znode *zn;
216
217 zn = kmalloc(c->max_znode_sz, GFP_NOFS);
218 if (unlikely(!zn))
219 return ERR_PTR(-ENOMEM);
220
221 memcpy(zn, znode, c->max_znode_sz);
222 zn->cnext = NULL;
223 __set_bit(DIRTY_ZNODE, &zn->flags);
224 __clear_bit(COW_ZNODE, &zn->flags);
225
226 ubifs_assert(!ubifs_zn_obsolete(znode));
227 __set_bit(OBSOLETE_ZNODE, &znode->flags);
228
229 if (znode->level != 0) {
230 int i;
231 const int n = zn->child_cnt;
232
233 /* The children now have new parent */
234 for (i = 0; i < n; i++) {
235 struct ubifs_zbranch *zbr = &zn->zbranch[i];
236
237 if (zbr->znode)
238 zbr->znode->parent = zn;
239 }
240 }
241
242 atomic_long_inc(&c->dirty_zn_cnt);
243 return zn;
244}
245
246/**
247 * add_idx_dirt - add dirt due to a dirty znode.
248 * @c: UBIFS file-system description object
249 * @lnum: LEB number of index node
250 * @dirt: size of index node
251 *
252 * This function updates lprops dirty space and the new size of the index.
253 */
254static int add_idx_dirt(struct ubifs_info *c, int lnum, int dirt)
255{
256 c->calc_idx_sz -= ALIGN(dirt, 8);
257 return ubifs_add_dirt(c, lnum, dirt);
258}
259
260/**
261 * dirty_cow_znode - ensure a znode is not being committed.
262 * @c: UBIFS file-system description object
263 * @zbr: branch of znode to check
264 *
265 * Returns dirtied znode on success or negative error code on failure.
266 */
267static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c,
268 struct ubifs_zbranch *zbr)
269{
270 struct ubifs_znode *znode = zbr->znode;
271 struct ubifs_znode *zn;
272 int err;
273
274 if (!ubifs_zn_cow(znode)) {
275 /* znode is not being committed */
276 if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) {
277 atomic_long_inc(&c->dirty_zn_cnt);
278 atomic_long_dec(&c->clean_zn_cnt);
279 atomic_long_dec(&ubifs_clean_zn_cnt);
280 err = add_idx_dirt(c, zbr->lnum, zbr->len);
281 if (unlikely(err))
282 return ERR_PTR(err);
283 }
284 return znode;
285 }
286
287 zn = copy_znode(c, znode);
288 if (IS_ERR(zn))
289 return zn;
290
291 if (zbr->len) {
292 err = insert_old_idx(c, zbr->lnum, zbr->offs);
293 if (unlikely(err))
294 return ERR_PTR(err);
295 err = add_idx_dirt(c, zbr->lnum, zbr->len);
296 } else
297 err = 0;
298
299 zbr->znode = zn;
300 zbr->lnum = 0;
301 zbr->offs = 0;
302 zbr->len = 0;
303
304 if (unlikely(err))
305 return ERR_PTR(err);
306 return zn;
307}
308
309/**
310 * lnc_add - add a leaf node to the leaf node cache.
311 * @c: UBIFS file-system description object
312 * @zbr: zbranch of leaf node
313 * @node: leaf node
314 *
315 * Leaf nodes are non-index nodes directory entry nodes or data nodes. The
316 * purpose of the leaf node cache is to save re-reading the same leaf node over
317 * and over again. Most things are cached by VFS, however the file system must
318 * cache directory entries for readdir and for resolving hash collisions. The
319 * present implementation of the leaf node cache is extremely simple, and
320 * allows for error returns that are not used but that may be needed if a more
321 * complex implementation is created.
322 *
323 * Note, this function does not add the @node object to LNC directly, but
324 * allocates a copy of the object and adds the copy to LNC. The reason for this
325 * is that @node has been allocated outside of the TNC subsystem and will be
326 * used with @c->tnc_mutex unlock upon return from the TNC subsystem. But LNC
327 * may be changed at any time, e.g. freed by the shrinker.
328 */
329static int lnc_add(struct ubifs_info *c, struct ubifs_zbranch *zbr,
330 const void *node)
331{
332 int err;
333 void *lnc_node;
334 const struct ubifs_dent_node *dent = node;
335
336 ubifs_assert(!zbr->leaf);
337 ubifs_assert(zbr->len != 0);
338 ubifs_assert(is_hash_key(c, &zbr->key));
339
340 err = ubifs_validate_entry(c, dent);
341 if (err) {
342 dbg_dump_stack();
343 dbg_dump_node(c, dent);
344 return err;
345 }
346
347 lnc_node = kmalloc(zbr->len, GFP_NOFS);
348 if (!lnc_node)
349 /* We don't have to have the cache, so no error */
350 return 0;
351
352 memcpy(lnc_node, node, zbr->len);
353 zbr->leaf = lnc_node;
354 return 0;
355}
356
357 /**
358 * lnc_add_directly - add a leaf node to the leaf-node-cache.
359 * @c: UBIFS file-system description object
360 * @zbr: zbranch of leaf node
361 * @node: leaf node
362 *
363 * This function is similar to 'lnc_add()', but it does not create a copy of
364 * @node but inserts @node to TNC directly.
365 */
366static int lnc_add_directly(struct ubifs_info *c, struct ubifs_zbranch *zbr,
367 void *node)
368{
369 int err;
370
371 ubifs_assert(!zbr->leaf);
372 ubifs_assert(zbr->len != 0);
373
374 err = ubifs_validate_entry(c, node);
375 if (err) {
376 dbg_dump_stack();
377 dbg_dump_node(c, node);
378 return err;
379 }
380
381 zbr->leaf = node;
382 return 0;
383}
384
385/**
386 * lnc_free - remove a leaf node from the leaf node cache.
387 * @zbr: zbranch of leaf node
388 * @node: leaf node
389 */
390static void lnc_free(struct ubifs_zbranch *zbr)
391{
392 if (!zbr->leaf)
393 return;
394 kfree(zbr->leaf);
395 zbr->leaf = NULL;
396}
397
398/**
399 * tnc_read_node_nm - read a "hashed" leaf node.
400 * @c: UBIFS file-system description object
401 * @zbr: key and position of the node
402 * @node: node is returned here
403 *
404 * This function reads a "hashed" node defined by @zbr from the leaf node cache
405 * (in it is there) or from the hash media, in which case the node is also
406 * added to LNC. Returns zero in case of success or a negative negative error
407 * code in case of failure.
408 */
409static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr,
410 void *node)
411{
412 int err;
413
414 ubifs_assert(is_hash_key(c, &zbr->key));
415
416 if (zbr->leaf) {
417 /* Read from the leaf node cache */
418 ubifs_assert(zbr->len != 0);
419 memcpy(node, zbr->leaf, zbr->len);
420 return 0;
421 }
422
423 err = ubifs_tnc_read_node(c, zbr, node);
424 if (err)
425 return err;
426
427 /* Add the node to the leaf node cache */
428 err = lnc_add(c, zbr, node);
429 return err;
430}
431
432/**
433 * try_read_node - read a node if it is a node.
434 * @c: UBIFS file-system description object
435 * @buf: buffer to read to
436 * @type: node type
437 * @len: node length (not aligned)
438 * @lnum: LEB number of node to read
439 * @offs: offset of node to read
440 *
441 * This function tries to read a node of known type and length, checks it and
442 * stores it in @buf. This function returns %1 if a node is present and %0 if
443 * a node is not present. A negative error code is returned for I/O errors.
444 * This function performs that same function as ubifs_read_node except that
445 * it does not require that there is actually a node present and instead
446 * the return code indicates if a node was read.
447 *
448 * Note, this function does not check CRC of data nodes if @c->no_chk_data_crc
449 * is true (it is controlled by corresponding mount option). However, if
450 * @c->mounting or @c->remounting_rw is true (we are mounting or re-mounting to
451 * R/W mode), @c->no_chk_data_crc is ignored and CRC is checked. This is
452 * because during mounting or re-mounting from R/O mode to R/W mode we may read
453 * journal nodes (when replying the journal or doing the recovery) and the
454 * journal nodes may potentially be corrupted, so checking is required.
455 */
456static int try_read_node(const struct ubifs_info *c, void *buf, int type,
457 int len, int lnum, int offs)
458{
459 int err, node_len;
460 struct ubifs_ch *ch = buf;
461 uint32_t crc, node_crc;
462
463 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
464
465 err = ubifs_leb_read(c, lnum, buf, offs, len, 1);
466 if (err) {
467 ubifs_err("cannot read node type %d from LEB %d:%d, error %d",
468 type, lnum, offs, err);
469 return err;
470 }
471
472 if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC)
473 return 0;
474
475 if (ch->node_type != type)
476 return 0;
477
478 node_len = le32_to_cpu(ch->len);
479 if (node_len != len)
480 return 0;
481
482 if (type == UBIFS_DATA_NODE && c->no_chk_data_crc && !c->mounting &&
483 !c->remounting_rw)
484 return 1;
485
486 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
487 node_crc = le32_to_cpu(ch->crc);
488 if (crc != node_crc)
489 return 0;
490
491 return 1;
492}
493
494/**
495 * fallible_read_node - try to read a leaf node.
496 * @c: UBIFS file-system description object
497 * @key: key of node to read
498 * @zbr: position of node
499 * @node: node returned
500 *
501 * This function tries to read a node and returns %1 if the node is read, %0
502 * if the node is not present, and a negative error code in the case of error.
503 */
504static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
505 struct ubifs_zbranch *zbr, void *node)
506{
507 int ret;
508
509 dbg_tnc("LEB %d:%d, key %s", zbr->lnum, zbr->offs, DBGKEY(key));
510
511 ret = try_read_node(c, node, key_type(c, key), zbr->len, zbr->lnum,
512 zbr->offs);
513 if (ret == 1) {
514 union ubifs_key node_key;
515 struct ubifs_dent_node *dent = node;
516
517 /* All nodes have key in the same place */
518 key_read(c, &dent->key, &node_key);
519 if (keys_cmp(c, key, &node_key) != 0)
520 ret = 0;
521 }
522 if (ret == 0 && c->replaying)
523 dbg_mnt("dangling branch LEB %d:%d len %d, key %s",
524 zbr->lnum, zbr->offs, zbr->len, DBGKEY(key));
525 return ret;
526}
527
528/**
529 * matches_name - determine if a direntry or xattr entry matches a given name.
530 * @c: UBIFS file-system description object
531 * @zbr: zbranch of dent
532 * @nm: name to match
533 *
534 * This function checks if xentry/direntry referred by zbranch @zbr matches name
535 * @nm. Returns %NAME_MATCHES if it does, %NAME_LESS if the name referred by
536 * @zbr is less than @nm, and %NAME_GREATER if it is greater than @nm. In case
537 * of failure, a negative error code is returned.
538 */
539static int matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr,
540 const struct qstr *nm)
541{
542 struct ubifs_dent_node *dent;
543 int nlen, err;
544
545 /* If possible, match against the dent in the leaf node cache */
546 if (!zbr->leaf) {
547 dent = kmalloc(zbr->len, GFP_NOFS);
548 if (!dent)
549 return -ENOMEM;
550
551 err = ubifs_tnc_read_node(c, zbr, dent);
552 if (err)
553 goto out_free;
554
555 /* Add the node to the leaf node cache */
556 err = lnc_add_directly(c, zbr, dent);
557 if (err)
558 goto out_free;
559 } else
560 dent = zbr->leaf;
561
562 nlen = le16_to_cpu(dent->nlen);
563 err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
564 if (err == 0) {
565 if (nlen == nm->len)
566 return NAME_MATCHES;
567 else if (nlen < nm->len)
568 return NAME_LESS;
569 else
570 return NAME_GREATER;
571 } else if (err < 0)
572 return NAME_LESS;
573 else
574 return NAME_GREATER;
575
576out_free:
577 kfree(dent);
578 return err;
579}
580
581/**
582 * get_znode - get a TNC znode that may not be loaded yet.
583 * @c: UBIFS file-system description object
584 * @znode: parent znode
585 * @n: znode branch slot number
586 *
587 * This function returns the znode or a negative error code.
588 */
589static struct ubifs_znode *get_znode(struct ubifs_info *c,
590 struct ubifs_znode *znode, int n)
591{
592 struct ubifs_zbranch *zbr;
593
594 zbr = &znode->zbranch[n];
595 if (zbr->znode)
596 znode = zbr->znode;
597 else
598 znode = ubifs_load_znode(c, zbr, znode, n);
599 return znode;
600}
601
602/**
603 * tnc_next - find next TNC entry.
604 * @c: UBIFS file-system description object
605 * @zn: znode is passed and returned here
606 * @n: znode branch slot number is passed and returned here
607 *
608 * This function returns %0 if the next TNC entry is found, %-ENOENT if there is
609 * no next entry, or a negative error code otherwise.
610 */
611static int tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
612{
613 struct ubifs_znode *znode = *zn;
614 int nn = *n;
615
616 nn += 1;
617 if (nn < znode->child_cnt) {
618 *n = nn;
619 return 0;
620 }
621 while (1) {
622 struct ubifs_znode *zp;
623
624 zp = znode->parent;
625 if (!zp)
626 return -ENOENT;
627 nn = znode->iip + 1;
628 znode = zp;
629 if (nn < znode->child_cnt) {
630 znode = get_znode(c, znode, nn);
631 if (IS_ERR(znode))
632 return PTR_ERR(znode);
633 while (znode->level != 0) {
634 znode = get_znode(c, znode, 0);
635 if (IS_ERR(znode))
636 return PTR_ERR(znode);
637 }
638 nn = 0;
639 break;
640 }
641 }
642 *zn = znode;
643 *n = nn;
644 return 0;
645}
646
647/**
648 * tnc_prev - find previous TNC entry.
649 * @c: UBIFS file-system description object
650 * @zn: znode is returned here
651 * @n: znode branch slot number is passed and returned here
652 *
653 * This function returns %0 if the previous TNC entry is found, %-ENOENT if
654 * there is no next entry, or a negative error code otherwise.
655 */
656static int tnc_prev(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
657{
658 struct ubifs_znode *znode = *zn;
659 int nn = *n;
660
661 if (nn > 0) {
662 *n = nn - 1;
663 return 0;
664 }
665 while (1) {
666 struct ubifs_znode *zp;
667
668 zp = znode->parent;
669 if (!zp)
670 return -ENOENT;
671 nn = znode->iip - 1;
672 znode = zp;
673 if (nn >= 0) {
674 znode = get_znode(c, znode, nn);
675 if (IS_ERR(znode))
676 return PTR_ERR(znode);
677 while (znode->level != 0) {
678 nn = znode->child_cnt - 1;
679 znode = get_znode(c, znode, nn);
680 if (IS_ERR(znode))
681 return PTR_ERR(znode);
682 }
683 nn = znode->child_cnt - 1;
684 break;
685 }
686 }
687 *zn = znode;
688 *n = nn;
689 return 0;
690}
691
692/**
693 * resolve_collision - resolve a collision.
694 * @c: UBIFS file-system description object
695 * @key: key of a directory or extended attribute entry
696 * @zn: znode is returned here
697 * @n: zbranch number is passed and returned here
698 * @nm: name of the entry
699 *
700 * This function is called for "hashed" keys to make sure that the found key
701 * really corresponds to the looked up node (directory or extended attribute
702 * entry). It returns %1 and sets @zn and @n if the collision is resolved.
703 * %0 is returned if @nm is not found and @zn and @n are set to the previous
704 * entry, i.e. to the entry after which @nm could follow if it were in TNC.
705 * This means that @n may be set to %-1 if the leftmost key in @zn is the
706 * previous one. A negative error code is returned on failures.
707 */
708static int resolve_collision(struct ubifs_info *c, const union ubifs_key *key,
709 struct ubifs_znode **zn, int *n,
710 const struct qstr *nm)
711{
712 int err;
713
714 err = matches_name(c, &(*zn)->zbranch[*n], nm);
715 if (unlikely(err < 0))
716 return err;
717 if (err == NAME_MATCHES)
718 return 1;
719
720 if (err == NAME_GREATER) {
721 /* Look left */
722 while (1) {
723 err = tnc_prev(c, zn, n);
724 if (err == -ENOENT) {
725 ubifs_assert(*n == 0);
726 *n = -1;
727 return 0;
728 }
729 if (err < 0)
730 return err;
731 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
732 /*
733 * We have found the branch after which we would
734 * like to insert, but inserting in this znode
735 * may still be wrong. Consider the following 3
736 * znodes, in the case where we are resolving a
737 * collision with Key2.
738 *
739 * znode zp
740 * ----------------------
741 * level 1 | Key0 | Key1 |
742 * -----------------------
743 * | |
744 * znode za | | znode zb
745 * ------------ ------------
746 * level 0 | Key0 | | Key2 |
747 * ------------ ------------
748 *
749 * The lookup finds Key2 in znode zb. Lets say
750 * there is no match and the name is greater so
751 * we look left. When we find Key0, we end up
752 * here. If we return now, we will insert into
753 * znode za at slot n = 1. But that is invalid
754 * according to the parent's keys. Key2 must
755 * be inserted into znode zb.
756 *
757 * Note, this problem is not relevant for the
758 * case when we go right, because
759 * 'tnc_insert()' would correct the parent key.
760 */
761 if (*n == (*zn)->child_cnt - 1) {
762 err = tnc_next(c, zn, n);
763 if (err) {
764 /* Should be impossible */
765 ubifs_assert(0);
766 if (err == -ENOENT)
767 err = -EINVAL;
768 return err;
769 }
770 ubifs_assert(*n == 0);
771 *n = -1;
772 }
773 return 0;
774 }
775 err = matches_name(c, &(*zn)->zbranch[*n], nm);
776 if (err < 0)
777 return err;
778 if (err == NAME_LESS)
779 return 0;
780 if (err == NAME_MATCHES)
781 return 1;
782 ubifs_assert(err == NAME_GREATER);
783 }
784 } else {
785 int nn = *n;
786 struct ubifs_znode *znode = *zn;
787
788 /* Look right */
789 while (1) {
790 err = tnc_next(c, &znode, &nn);
791 if (err == -ENOENT)
792 return 0;
793 if (err < 0)
794 return err;
795 if (keys_cmp(c, &znode->zbranch[nn].key, key))
796 return 0;
797 err = matches_name(c, &znode->zbranch[nn], nm);
798 if (err < 0)
799 return err;
800 if (err == NAME_GREATER)
801 return 0;
802 *zn = znode;
803 *n = nn;
804 if (err == NAME_MATCHES)
805 return 1;
806 ubifs_assert(err == NAME_LESS);
807 }
808 }
809}
810
811/**
812 * fallible_matches_name - determine if a dent matches a given name.
813 * @c: UBIFS file-system description object
814 * @zbr: zbranch of dent
815 * @nm: name to match
816 *
817 * This is a "fallible" version of 'matches_name()' function which does not
818 * panic if the direntry/xentry referred by @zbr does not exist on the media.
819 *
820 * This function checks if xentry/direntry referred by zbranch @zbr matches name
821 * @nm. Returns %NAME_MATCHES it does, %NAME_LESS if the name referred by @zbr
822 * is less than @nm, %NAME_GREATER if it is greater than @nm, and @NOT_ON_MEDIA
823 * if xentry/direntry referred by @zbr does not exist on the media. A negative
824 * error code is returned in case of failure.
825 */
826static int fallible_matches_name(struct ubifs_info *c,
827 struct ubifs_zbranch *zbr,
828 const struct qstr *nm)
829{
830 struct ubifs_dent_node *dent;
831 int nlen, err;
832
833 /* If possible, match against the dent in the leaf node cache */
834 if (!zbr->leaf) {
835 dent = kmalloc(zbr->len, GFP_NOFS);
836 if (!dent)
837 return -ENOMEM;
838
839 err = fallible_read_node(c, &zbr->key, zbr, dent);
840 if (err < 0)
841 goto out_free;
842 if (err == 0) {
843 /* The node was not present */
844 err = NOT_ON_MEDIA;
845 goto out_free;
846 }
847 ubifs_assert(err == 1);
848
849 err = lnc_add_directly(c, zbr, dent);
850 if (err)
851 goto out_free;
852 } else
853 dent = zbr->leaf;
854
855 nlen = le16_to_cpu(dent->nlen);
856 err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
857 if (err == 0) {
858 if (nlen == nm->len)
859 return NAME_MATCHES;
860 else if (nlen < nm->len)
861 return NAME_LESS;
862 else
863 return NAME_GREATER;
864 } else if (err < 0)
865 return NAME_LESS;
866 else
867 return NAME_GREATER;
868
869out_free:
870 kfree(dent);
871 return err;
872}
873
874/**
875 * fallible_resolve_collision - resolve a collision even if nodes are missing.
876 * @c: UBIFS file-system description object
877 * @key: key
878 * @zn: znode is returned here
879 * @n: branch number is passed and returned here
880 * @nm: name of directory entry
881 * @adding: indicates caller is adding a key to the TNC
882 *
883 * This is a "fallible" version of the 'resolve_collision()' function which
884 * does not panic if one of the nodes referred to by TNC does not exist on the
885 * media. This may happen when replaying the journal if a deleted node was
886 * Garbage-collected and the commit was not done. A branch that refers to a node
887 * that is not present is called a dangling branch. The following are the return
888 * codes for this function:
889 * o if @nm was found, %1 is returned and @zn and @n are set to the found
890 * branch;
891 * o if we are @adding and @nm was not found, %0 is returned;
892 * o if we are not @adding and @nm was not found, but a dangling branch was
893 * found, then %1 is returned and @zn and @n are set to the dangling branch;
894 * o a negative error code is returned in case of failure.
895 */
896static int fallible_resolve_collision(struct ubifs_info *c,
897 const union ubifs_key *key,
898 struct ubifs_znode **zn, int *n,
899 const struct qstr *nm, int adding)
900{
901 struct ubifs_znode *o_znode = NULL, *znode = *zn;
902 int uninitialized_var(o_n), err, cmp, unsure = 0, nn = *n;
903
904 cmp = fallible_matches_name(c, &znode->zbranch[nn], nm);
905 if (unlikely(cmp < 0))
906 return cmp;
907 if (cmp == NAME_MATCHES)
908 return 1;
909 if (cmp == NOT_ON_MEDIA) {
910 o_znode = znode;
911 o_n = nn;
912 /*
913 * We are unlucky and hit a dangling branch straight away.
914 * Now we do not really know where to go to find the needed
915 * branch - to the left or to the right. Well, let's try left.
916 */
917 unsure = 1;
918 } else if (!adding)
919 unsure = 1; /* Remove a dangling branch wherever it is */
920
921 if (cmp == NAME_GREATER || unsure) {
922 /* Look left */
923 while (1) {
924 err = tnc_prev(c, zn, n);
925 if (err == -ENOENT) {
926 ubifs_assert(*n == 0);
927 *n = -1;
928 break;
929 }
930 if (err < 0)
931 return err;
932 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
933 /* See comments in 'resolve_collision()' */
934 if (*n == (*zn)->child_cnt - 1) {
935 err = tnc_next(c, zn, n);
936 if (err) {
937 /* Should be impossible */
938 ubifs_assert(0);
939 if (err == -ENOENT)
940 err = -EINVAL;
941 return err;
942 }
943 ubifs_assert(*n == 0);
944 *n = -1;
945 }
946 break;
947 }
948 err = fallible_matches_name(c, &(*zn)->zbranch[*n], nm);
949 if (err < 0)
950 return err;
951 if (err == NAME_MATCHES)
952 return 1;
953 if (err == NOT_ON_MEDIA) {
954 o_znode = *zn;
955 o_n = *n;
956 continue;
957 }
958 if (!adding)
959 continue;
960 if (err == NAME_LESS)
961 break;
962 else
963 unsure = 0;
964 }
965 }
966
967 if (cmp == NAME_LESS || unsure) {
968 /* Look right */
969 *zn = znode;
970 *n = nn;
971 while (1) {
972 err = tnc_next(c, &znode, &nn);
973 if (err == -ENOENT)
974 break;
975 if (err < 0)
976 return err;
977 if (keys_cmp(c, &znode->zbranch[nn].key, key))
978 break;
979 err = fallible_matches_name(c, &znode->zbranch[nn], nm);
980 if (err < 0)
981 return err;
982 if (err == NAME_GREATER)
983 break;
984 *zn = znode;
985 *n = nn;
986 if (err == NAME_MATCHES)
987 return 1;
988 if (err == NOT_ON_MEDIA) {
989 o_znode = znode;
990 o_n = nn;
991 }
992 }
993 }
994
995 /* Never match a dangling branch when adding */
996 if (adding || !o_znode)
997 return 0;
998
999 dbg_mnt("dangling match LEB %d:%d len %d %s",
1000 o_znode->zbranch[o_n].lnum, o_znode->zbranch[o_n].offs,
1001 o_znode->zbranch[o_n].len, DBGKEY(key));
1002 *zn = o_znode;
1003 *n = o_n;
1004 return 1;
1005}
1006
1007/**
1008 * matches_position - determine if a zbranch matches a given position.
1009 * @zbr: zbranch of dent
1010 * @lnum: LEB number of dent to match
1011 * @offs: offset of dent to match
1012 *
1013 * This function returns %1 if @lnum:@offs matches, and %0 otherwise.
1014 */
1015static int matches_position(struct ubifs_zbranch *zbr, int lnum, int offs)
1016{
1017 if (zbr->lnum == lnum && zbr->offs == offs)
1018 return 1;
1019 else
1020 return 0;
1021}
1022
1023/**
1024 * resolve_collision_directly - resolve a collision directly.
1025 * @c: UBIFS file-system description object
1026 * @key: key of directory entry
1027 * @zn: znode is passed and returned here
1028 * @n: zbranch number is passed and returned here
1029 * @lnum: LEB number of dent node to match
1030 * @offs: offset of dent node to match
1031 *
1032 * This function is used for "hashed" keys to make sure the found directory or
1033 * extended attribute entry node is what was looked for. It is used when the
1034 * flash address of the right node is known (@lnum:@offs) which makes it much
1035 * easier to resolve collisions (no need to read entries and match full
1036 * names). This function returns %1 and sets @zn and @n if the collision is
1037 * resolved, %0 if @lnum:@offs is not found and @zn and @n are set to the
1038 * previous directory entry. Otherwise a negative error code is returned.
1039 */
1040static int resolve_collision_directly(struct ubifs_info *c,
1041 const union ubifs_key *key,
1042 struct ubifs_znode **zn, int *n,
1043 int lnum, int offs)
1044{
1045 struct ubifs_znode *znode;
1046 int nn, err;
1047
1048 znode = *zn;
1049 nn = *n;
1050 if (matches_position(&znode->zbranch[nn], lnum, offs))
1051 return 1;
1052
1053 /* Look left */
1054 while (1) {
1055 err = tnc_prev(c, &znode, &nn);
1056 if (err == -ENOENT)
1057 break;
1058 if (err < 0)
1059 return err;
1060 if (keys_cmp(c, &znode->zbranch[nn].key, key))
1061 break;
1062 if (matches_position(&znode->zbranch[nn], lnum, offs)) {
1063 *zn = znode;
1064 *n = nn;
1065 return 1;
1066 }
1067 }
1068
1069 /* Look right */
1070 znode = *zn;
1071 nn = *n;
1072 while (1) {
1073 err = tnc_next(c, &znode, &nn);
1074 if (err == -ENOENT)
1075 return 0;
1076 if (err < 0)
1077 return err;
1078 if (keys_cmp(c, &znode->zbranch[nn].key, key))
1079 return 0;
1080 *zn = znode;
1081 *n = nn;
1082 if (matches_position(&znode->zbranch[nn], lnum, offs))
1083 return 1;
1084 }
1085}
1086
1087/**
1088 * dirty_cow_bottom_up - dirty a znode and its ancestors.
1089 * @c: UBIFS file-system description object
1090 * @znode: znode to dirty
1091 *
1092 * If we do not have a unique key that resides in a znode, then we cannot
1093 * dirty that znode from the top down (i.e. by using lookup_level0_dirty)
1094 * This function records the path back to the last dirty ancestor, and then
1095 * dirties the znodes on that path.
1096 */
1097static struct ubifs_znode *dirty_cow_bottom_up(struct ubifs_info *c,
1098 struct ubifs_znode *znode)
1099{
1100 struct ubifs_znode *zp;
1101 int *path = c->bottom_up_buf, p = 0;
1102
1103 ubifs_assert(c->zroot.znode);
1104 ubifs_assert(znode);
1105 if (c->zroot.znode->level > BOTTOM_UP_HEIGHT) {
1106 kfree(c->bottom_up_buf);
1107 c->bottom_up_buf = kmalloc(c->zroot.znode->level * sizeof(int),
1108 GFP_NOFS);
1109 if (!c->bottom_up_buf)
1110 return ERR_PTR(-ENOMEM);
1111 path = c->bottom_up_buf;
1112 }
1113 if (c->zroot.znode->level) {
1114 /* Go up until parent is dirty */
1115 while (1) {
1116 int n;
1117
1118 zp = znode->parent;
1119 if (!zp)
1120 break;
1121 n = znode->iip;
1122 ubifs_assert(p < c->zroot.znode->level);
1123 path[p++] = n;
1124 if (!zp->cnext && ubifs_zn_dirty(znode))
1125 break;
1126 znode = zp;
1127 }
1128 }
1129
1130 /* Come back down, dirtying as we go */
1131 while (1) {
1132 struct ubifs_zbranch *zbr;
1133
1134 zp = znode->parent;
1135 if (zp) {
1136 ubifs_assert(path[p - 1] >= 0);
1137 ubifs_assert(path[p - 1] < zp->child_cnt);
1138 zbr = &zp->zbranch[path[--p]];
1139 znode = dirty_cow_znode(c, zbr);
1140 } else {
1141 ubifs_assert(znode == c->zroot.znode);
1142 znode = dirty_cow_znode(c, &c->zroot);
1143 }
1144 if (IS_ERR(znode) || !p)
1145 break;
1146 ubifs_assert(path[p - 1] >= 0);
1147 ubifs_assert(path[p - 1] < znode->child_cnt);
1148 znode = znode->zbranch[path[p - 1]].znode;
1149 }
1150
1151 return znode;
1152}
1153
1154/**
1155 * ubifs_lookup_level0 - search for zero-level znode.
1156 * @c: UBIFS file-system description object
1157 * @key: key to lookup
1158 * @zn: znode is returned here
1159 * @n: znode branch slot number is returned here
1160 *
1161 * This function looks up the TNC tree and search for zero-level znode which
1162 * refers key @key. The found zero-level znode is returned in @zn. There are 3
1163 * cases:
1164 * o exact match, i.e. the found zero-level znode contains key @key, then %1
1165 * is returned and slot number of the matched branch is stored in @n;
1166 * o not exact match, which means that zero-level znode does not contain
1167 * @key, then %0 is returned and slot number of the closest branch is stored
1168 * in @n;
1169 * o @key is so small that it is even less than the lowest key of the
1170 * leftmost zero-level node, then %0 is returned and %0 is stored in @n.
1171 *
1172 * Note, when the TNC tree is traversed, some znodes may be absent, then this
1173 * function reads corresponding indexing nodes and inserts them to TNC. In
1174 * case of failure, a negative error code is returned.
1175 */
1176int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
1177 struct ubifs_znode **zn, int *n)
1178{
1179 int err, exact;
1180 struct ubifs_znode *znode;
1181 unsigned long time = get_seconds();
1182
1183 dbg_tnc("search key %s", DBGKEY(key));
1184 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
1185
1186 znode = c->zroot.znode;
1187 if (unlikely(!znode)) {
1188 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
1189 if (IS_ERR(znode))
1190 return PTR_ERR(znode);
1191 }
1192
1193 znode->time = time;
1194
1195 while (1) {
1196 struct ubifs_zbranch *zbr;
1197
1198 exact = ubifs_search_zbranch(c, znode, key, n);
1199
1200 if (znode->level == 0)
1201 break;
1202
1203 if (*n < 0)
1204 *n = 0;
1205 zbr = &znode->zbranch[*n];
1206
1207 if (zbr->znode) {
1208 znode->time = time;
1209 znode = zbr->znode;
1210 continue;
1211 }
1212
1213 /* znode is not in TNC cache, load it from the media */
1214 znode = ubifs_load_znode(c, zbr, znode, *n);
1215 if (IS_ERR(znode))
1216 return PTR_ERR(znode);
1217 }
1218
1219 *zn = znode;
1220 if (exact || !is_hash_key(c, key) || *n != -1) {
1221 dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
1222 return exact;
1223 }
1224
1225 /*
1226 * Here is a tricky place. We have not found the key and this is a
1227 * "hashed" key, which may collide. The rest of the code deals with
1228 * situations like this:
1229 *
1230 * | 3 | 5 |
1231 * / \
1232 * | 3 | 5 | | 6 | 7 | (x)
1233 *
1234 * Or more a complex example:
1235 *
1236 * | 1 | 5 |
1237 * / \
1238 * | 1 | 3 | | 5 | 8 |
1239 * \ /
1240 * | 5 | 5 | | 6 | 7 | (x)
1241 *
1242 * In the examples, if we are looking for key "5", we may reach nodes
1243 * marked with "(x)". In this case what we have do is to look at the
1244 * left and see if there is "5" key there. If there is, we have to
1245 * return it.
1246 *
1247 * Note, this whole situation is possible because we allow to have
1248 * elements which are equivalent to the next key in the parent in the
1249 * children of current znode. For example, this happens if we split a
1250 * znode like this: | 3 | 5 | 5 | 6 | 7 |, which results in something
1251 * like this:
1252 * | 3 | 5 |
1253 * / \
1254 * | 3 | 5 | | 5 | 6 | 7 |
1255 * ^
1256 * And this becomes what is at the first "picture" after key "5" marked
1257 * with "^" is removed. What could be done is we could prohibit
1258 * splitting in the middle of the colliding sequence. Also, when
1259 * removing the leftmost key, we would have to correct the key of the
1260 * parent node, which would introduce additional complications. Namely,
1261 * if we changed the leftmost key of the parent znode, the garbage
1262 * collector would be unable to find it (GC is doing this when GC'ing
1263 * indexing LEBs). Although we already have an additional RB-tree where
1264 * we save such changed znodes (see 'ins_clr_old_idx_znode()') until
1265 * after the commit. But anyway, this does not look easy to implement
1266 * so we did not try this.
1267 */
1268 err = tnc_prev(c, &znode, n);
1269 if (err == -ENOENT) {
1270 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1271 *n = -1;
1272 return 0;
1273 }
1274 if (unlikely(err < 0))
1275 return err;
1276 if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
1277 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1278 *n = -1;
1279 return 0;
1280 }
1281
1282 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1283 *zn = znode;
1284 return 1;
1285}
1286
1287/**
1288 * lookup_level0_dirty - search for zero-level znode dirtying.
1289 * @c: UBIFS file-system description object
1290 * @key: key to lookup
1291 * @zn: znode is returned here
1292 * @n: znode branch slot number is returned here
1293 *
1294 * This function looks up the TNC tree and search for zero-level znode which
1295 * refers key @key. The found zero-level znode is returned in @zn. There are 3
1296 * cases:
1297 * o exact match, i.e. the found zero-level znode contains key @key, then %1
1298 * is returned and slot number of the matched branch is stored in @n;
1299 * o not exact match, which means that zero-level znode does not contain @key
1300 * then %0 is returned and slot number of the closed branch is stored in
1301 * @n;
1302 * o @key is so small that it is even less than the lowest key of the
1303 * leftmost zero-level node, then %0 is returned and %-1 is stored in @n.
1304 *
1305 * Additionally all znodes in the path from the root to the located zero-level
1306 * znode are marked as dirty.
1307 *
1308 * Note, when the TNC tree is traversed, some znodes may be absent, then this
1309 * function reads corresponding indexing nodes and inserts them to TNC. In
1310 * case of failure, a negative error code is returned.
1311 */
1312static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key,
1313 struct ubifs_znode **zn, int *n)
1314{
1315 int err, exact;
1316 struct ubifs_znode *znode;
1317 unsigned long time = get_seconds();
1318
1319 dbg_tnc("search and dirty key %s", DBGKEY(key));
1320
1321 znode = c->zroot.znode;
1322 if (unlikely(!znode)) {
1323 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
1324 if (IS_ERR(znode))
1325 return PTR_ERR(znode);
1326 }
1327
1328 znode = dirty_cow_znode(c, &c->zroot);
1329 if (IS_ERR(znode))
1330 return PTR_ERR(znode);
1331
1332 znode->time = time;
1333
1334 while (1) {
1335 struct ubifs_zbranch *zbr;
1336
1337 exact = ubifs_search_zbranch(c, znode, key, n);
1338
1339 if (znode->level == 0)
1340 break;
1341
1342 if (*n < 0)
1343 *n = 0;
1344 zbr = &znode->zbranch[*n];
1345
1346 if (zbr->znode) {
1347 znode->time = time;
1348 znode = dirty_cow_znode(c, zbr);
1349 if (IS_ERR(znode))
1350 return PTR_ERR(znode);
1351 continue;
1352 }
1353
1354 /* znode is not in TNC cache, load it from the media */
1355 znode = ubifs_load_znode(c, zbr, znode, *n);
1356 if (IS_ERR(znode))
1357 return PTR_ERR(znode);
1358 znode = dirty_cow_znode(c, zbr);
1359 if (IS_ERR(znode))
1360 return PTR_ERR(znode);
1361 }
1362
1363 *zn = znode;
1364 if (exact || !is_hash_key(c, key) || *n != -1) {
1365 dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
1366 return exact;
1367 }
1368
1369 /*
1370 * See huge comment at 'lookup_level0_dirty()' what is the rest of the
1371 * code.
1372 */
1373 err = tnc_prev(c, &znode, n);
1374 if (err == -ENOENT) {
1375 *n = -1;
1376 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1377 return 0;
1378 }
1379 if (unlikely(err < 0))
1380 return err;
1381 if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
1382 *n = -1;
1383 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1384 return 0;
1385 }
1386
1387 if (znode->cnext || !ubifs_zn_dirty(znode)) {
1388 znode = dirty_cow_bottom_up(c, znode);
1389 if (IS_ERR(znode))
1390 return PTR_ERR(znode);
1391 }
1392
1393 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1394 *zn = znode;
1395 return 1;
1396}
1397
1398/**
1399 * maybe_leb_gced - determine if a LEB may have been garbage collected.
1400 * @c: UBIFS file-system description object
1401 * @lnum: LEB number
1402 * @gc_seq1: garbage collection sequence number
1403 *
1404 * This function determines if @lnum may have been garbage collected since
1405 * sequence number @gc_seq1. If it may have been then %1 is returned, otherwise
1406 * %0 is returned.
1407 */
1408static int maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1)
1409{
1410 int gc_seq2, gced_lnum;
1411
1412 gced_lnum = c->gced_lnum;
1413 smp_rmb();
1414 gc_seq2 = c->gc_seq;
1415 /* Same seq means no GC */
1416 if (gc_seq1 == gc_seq2)
1417 return 0;
1418 /* Different by more than 1 means we don't know */
1419 if (gc_seq1 + 1 != gc_seq2)
1420 return 1;
1421 /*
1422 * We have seen the sequence number has increased by 1. Now we need to
1423 * be sure we read the right LEB number, so read it again.
1424 */
1425 smp_rmb();
1426 if (gced_lnum != c->gced_lnum)
1427 return 1;
1428 /* Finally we can check lnum */
1429 if (gced_lnum == lnum)
1430 return 1;
1431 return 0;
1432}
1433
1434/**
1435 * ubifs_tnc_locate - look up a file-system node and return it and its location.
1436 * @c: UBIFS file-system description object
1437 * @key: node key to lookup
1438 * @node: the node is returned here
1439 * @lnum: LEB number is returned here
1440 * @offs: offset is returned here
1441 *
1442 * This function looks up and reads node with key @key. The caller has to make
1443 * sure the @node buffer is large enough to fit the node. Returns zero in case
1444 * of success, %-ENOENT if the node was not found, and a negative error code in
1445 * case of failure. The node location can be returned in @lnum and @offs.
1446 */
1447int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key,
1448 void *node, int *lnum, int *offs)
1449{
1450 int found, n, err, safely = 0, gc_seq1;
1451 struct ubifs_znode *znode;
1452 struct ubifs_zbranch zbr, *zt;
1453
1454again:
1455 mutex_lock(&c->tnc_mutex);
1456 found = ubifs_lookup_level0(c, key, &znode, &n);
1457 if (!found) {
1458 err = -ENOENT;
1459 goto out;
1460 } else if (found < 0) {
1461 err = found;
1462 goto out;
1463 }
1464 zt = &znode->zbranch[n];
1465 if (lnum) {
1466 *lnum = zt->lnum;
1467 *offs = zt->offs;
1468 }
1469 if (is_hash_key(c, key)) {
1470 /*
1471 * In this case the leaf node cache gets used, so we pass the
1472 * address of the zbranch and keep the mutex locked
1473 */
1474 err = tnc_read_node_nm(c, zt, node);
1475 goto out;
1476 }
1477 if (safely) {
1478 err = ubifs_tnc_read_node(c, zt, node);
1479 goto out;
1480 }
1481 /* Drop the TNC mutex prematurely and race with garbage collection */
1482 zbr = znode->zbranch[n];
1483 gc_seq1 = c->gc_seq;
1484 mutex_unlock(&c->tnc_mutex);
1485
1486 if (ubifs_get_wbuf(c, zbr.lnum)) {
1487 /* We do not GC journal heads */
1488 err = ubifs_tnc_read_node(c, &zbr, node);
1489 return err;
1490 }
1491
1492 err = fallible_read_node(c, key, &zbr, node);
1493 if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) {
1494 /*
1495 * The node may have been GC'ed out from under us so try again
1496 * while keeping the TNC mutex locked.
1497 */
1498 safely = 1;
1499 goto again;
1500 }
1501 return 0;
1502
1503out:
1504 mutex_unlock(&c->tnc_mutex);
1505 return err;
1506}
1507
1508/**
1509 * ubifs_tnc_get_bu_keys - lookup keys for bulk-read.
1510 * @c: UBIFS file-system description object
1511 * @bu: bulk-read parameters and results
1512 *
1513 * Lookup consecutive data node keys for the same inode that reside
1514 * consecutively in the same LEB. This function returns zero in case of success
1515 * and a negative error code in case of failure.
1516 *
1517 * Note, if the bulk-read buffer length (@bu->buf_len) is known, this function
1518 * makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares
1519 * maximum possible amount of nodes for bulk-read.
1520 */
1521int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)
1522{
1523 int n, err = 0, lnum = -1, uninitialized_var(offs);
1524 int uninitialized_var(len);
1525 unsigned int block = key_block(c, &bu->key);
1526 struct ubifs_znode *znode;
1527
1528 bu->cnt = 0;
1529 bu->blk_cnt = 0;
1530 bu->eof = 0;
1531
1532 mutex_lock(&c->tnc_mutex);
1533 /* Find first key */
1534 err = ubifs_lookup_level0(c, &bu->key, &znode, &n);
1535 if (err < 0)
1536 goto out;
1537 if (err) {
1538 /* Key found */
1539 len = znode->zbranch[n].len;
1540 /* The buffer must be big enough for at least 1 node */
1541 if (len > bu->buf_len) {
1542 err = -EINVAL;
1543 goto out;
1544 }
1545 /* Add this key */
1546 bu->zbranch[bu->cnt++] = znode->zbranch[n];
1547 bu->blk_cnt += 1;
1548 lnum = znode->zbranch[n].lnum;
1549 offs = ALIGN(znode->zbranch[n].offs + len, 8);
1550 }
1551 while (1) {
1552 struct ubifs_zbranch *zbr;
1553 union ubifs_key *key;
1554 unsigned int next_block;
1555
1556 /* Find next key */
1557 err = tnc_next(c, &znode, &n);
1558 if (err)
1559 goto out;
1560 zbr = &znode->zbranch[n];
1561 key = &zbr->key;
1562 /* See if there is another data key for this file */
1563 if (key_inum(c, key) != key_inum(c, &bu->key) ||
1564 key_type(c, key) != UBIFS_DATA_KEY) {
1565 err = -ENOENT;
1566 goto out;
1567 }
1568 if (lnum < 0) {
1569 /* First key found */
1570 lnum = zbr->lnum;
1571 offs = ALIGN(zbr->offs + zbr->len, 8);
1572 len = zbr->len;
1573 if (len > bu->buf_len) {
1574 err = -EINVAL;
1575 goto out;
1576 }
1577 } else {
1578 /*
1579 * The data nodes must be in consecutive positions in
1580 * the same LEB.
1581 */
1582 if (zbr->lnum != lnum || zbr->offs != offs)
1583 goto out;
1584 offs += ALIGN(zbr->len, 8);
1585 len = ALIGN(len, 8) + zbr->len;
1586 /* Must not exceed buffer length */
1587 if (len > bu->buf_len)
1588 goto out;
1589 }
1590 /* Allow for holes */
1591 next_block = key_block(c, key);
1592 bu->blk_cnt += (next_block - block - 1);
1593 if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
1594 goto out;
1595 block = next_block;
1596 /* Add this key */
1597 bu->zbranch[bu->cnt++] = *zbr;
1598 bu->blk_cnt += 1;
1599 /* See if we have room for more */
1600 if (bu->cnt >= UBIFS_MAX_BULK_READ)
1601 goto out;
1602 if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
1603 goto out;
1604 }
1605out:
1606 if (err == -ENOENT) {
1607 bu->eof = 1;
1608 err = 0;
1609 }
1610 bu->gc_seq = c->gc_seq;
1611 mutex_unlock(&c->tnc_mutex);
1612 if (err)
1613 return err;
1614 /*
1615 * An enormous hole could cause bulk-read to encompass too many
1616 * page cache pages, so limit the number here.
1617 */
1618 if (bu->blk_cnt > UBIFS_MAX_BULK_READ)
1619 bu->blk_cnt = UBIFS_MAX_BULK_READ;
1620 /*
1621 * Ensure that bulk-read covers a whole number of page cache
1622 * pages.
1623 */
1624 if (UBIFS_BLOCKS_PER_PAGE == 1 ||
1625 !(bu->blk_cnt & (UBIFS_BLOCKS_PER_PAGE - 1)))
1626 return 0;
1627 if (bu->eof) {
1628 /* At the end of file we can round up */
1629 bu->blk_cnt += UBIFS_BLOCKS_PER_PAGE - 1;
1630 return 0;
1631 }
1632 /* Exclude data nodes that do not make up a whole page cache page */
1633 block = key_block(c, &bu->key) + bu->blk_cnt;
1634 block &= ~(UBIFS_BLOCKS_PER_PAGE - 1);
1635 while (bu->cnt) {
1636 if (key_block(c, &bu->zbranch[bu->cnt - 1].key) < block)
1637 break;
1638 bu->cnt -= 1;
1639 }
1640 return 0;
1641}
1642
1643/**
1644 * read_wbuf - bulk-read from a LEB with a wbuf.
1645 * @wbuf: wbuf that may overlap the read
1646 * @buf: buffer into which to read
1647 * @len: read length
1648 * @lnum: LEB number from which to read
1649 * @offs: offset from which to read
1650 *
1651 * This functions returns %0 on success or a negative error code on failure.
1652 */
1653static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum,
1654 int offs)
1655{
1656 const struct ubifs_info *c = wbuf->c;
1657 int rlen, overlap;
1658
1659 dbg_io("LEB %d:%d, length %d", lnum, offs, len);
1660 ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
1661 ubifs_assert(!(offs & 7) && offs < c->leb_size);
1662 ubifs_assert(offs + len <= c->leb_size);
1663
1664 spin_lock(&wbuf->lock);
1665 overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
1666 if (!overlap) {
1667 /* We may safely unlock the write-buffer and read the data */
1668 spin_unlock(&wbuf->lock);
1669 return ubifs_leb_read(c, lnum, buf, offs, len, 0);
1670 }
1671
1672 /* Don't read under wbuf */
1673 rlen = wbuf->offs - offs;
1674 if (rlen < 0)
1675 rlen = 0;
1676
1677 /* Copy the rest from the write-buffer */
1678 memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
1679 spin_unlock(&wbuf->lock);
1680
1681 if (rlen > 0)
1682 /* Read everything that goes before write-buffer */
1683 return ubifs_leb_read(c, lnum, buf, offs, rlen, 0);
1684
1685 return 0;
1686}
1687
1688/**
1689 * validate_data_node - validate data nodes for bulk-read.
1690 * @c: UBIFS file-system description object
1691 * @buf: buffer containing data node to validate
1692 * @zbr: zbranch of data node to validate
1693 *
1694 * This functions returns %0 on success or a negative error code on failure.
1695 */
1696static int validate_data_node(struct ubifs_info *c, void *buf,
1697 struct ubifs_zbranch *zbr)
1698{
1699 union ubifs_key key1;
1700 struct ubifs_ch *ch = buf;
1701 int err, len;
1702
1703 if (ch->node_type != UBIFS_DATA_NODE) {
1704 ubifs_err("bad node type (%d but expected %d)",
1705 ch->node_type, UBIFS_DATA_NODE);
1706 goto out_err;
1707 }
1708
1709 err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0, 0);
1710 if (err) {
1711 ubifs_err("expected node type %d", UBIFS_DATA_NODE);
1712 goto out;
1713 }
1714
1715 len = le32_to_cpu(ch->len);
1716 if (len != zbr->len) {
1717 ubifs_err("bad node length %d, expected %d", len, zbr->len);
1718 goto out_err;
1719 }
1720
1721 /* Make sure the key of the read node is correct */
1722 key_read(c, buf + UBIFS_KEY_OFFSET, &key1);
1723 if (!keys_eq(c, &zbr->key, &key1)) {
1724 ubifs_err("bad key in node at LEB %d:%d",
1725 zbr->lnum, zbr->offs);
1726 dbg_tnc("looked for key %s found node's key %s",
1727 DBGKEY(&zbr->key), DBGKEY1(&key1));
1728 goto out_err;
1729 }
1730
1731 return 0;
1732
1733out_err:
1734 err = -EINVAL;
1735out:
1736 ubifs_err("bad node at LEB %d:%d", zbr->lnum, zbr->offs);
1737 dbg_dump_node(c, buf);
1738 dbg_dump_stack();
1739 return err;
1740}
1741
1742/**
1743 * ubifs_tnc_bulk_read - read a number of data nodes in one go.
1744 * @c: UBIFS file-system description object
1745 * @bu: bulk-read parameters and results
1746 *
1747 * This functions reads and validates the data nodes that were identified by the
1748 * 'ubifs_tnc_get_bu_keys()' function. This functions returns %0 on success,
1749 * -EAGAIN to indicate a race with GC, or another negative error code on
1750 * failure.
1751 */
1752int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu)
1753{
1754 int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i;
1755 struct ubifs_wbuf *wbuf;
1756 void *buf;
1757
1758 len = bu->zbranch[bu->cnt - 1].offs;
1759 len += bu->zbranch[bu->cnt - 1].len - offs;
1760 if (len > bu->buf_len) {
1761 ubifs_err("buffer too small %d vs %d", bu->buf_len, len);
1762 return -EINVAL;
1763 }
1764
1765 /* Do the read */
1766 wbuf = ubifs_get_wbuf(c, lnum);
1767 if (wbuf)
1768 err = read_wbuf(wbuf, bu->buf, len, lnum, offs);
1769 else
1770 err = ubifs_leb_read(c, lnum, bu->buf, offs, len, 0);
1771
1772 /* Check for a race with GC */
1773 if (maybe_leb_gced(c, lnum, bu->gc_seq))
1774 return -EAGAIN;
1775
1776 if (err && err != -EBADMSG) {
1777 ubifs_err("failed to read from LEB %d:%d, error %d",
1778 lnum, offs, err);
1779 dbg_dump_stack();
1780 dbg_tnc("key %s", DBGKEY(&bu->key));
1781 return err;
1782 }
1783
1784 /* Validate the nodes read */
1785 buf = bu->buf;
1786 for (i = 0; i < bu->cnt; i++) {
1787 err = validate_data_node(c, buf, &bu->zbranch[i]);
1788 if (err)
1789 return err;
1790 buf = buf + ALIGN(bu->zbranch[i].len, 8);
1791 }
1792
1793 return 0;
1794}
1795
1796/**
1797 * do_lookup_nm- look up a "hashed" node.
1798 * @c: UBIFS file-system description object
1799 * @key: node key to lookup
1800 * @node: the node is returned here
1801 * @nm: node name
1802 *
1803 * This function look up and reads a node which contains name hash in the key.
1804 * Since the hash may have collisions, there may be many nodes with the same
1805 * key, so we have to sequentially look to all of them until the needed one is
1806 * found. This function returns zero in case of success, %-ENOENT if the node
1807 * was not found, and a negative error code in case of failure.
1808 */
1809static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1810 void *node, const struct qstr *nm)
1811{
1812 int found, n, err;
1813 struct ubifs_znode *znode;
1814
1815 dbg_tnc("name '%.*s' key %s", nm->len, nm->name, DBGKEY(key));
1816 mutex_lock(&c->tnc_mutex);
1817 found = ubifs_lookup_level0(c, key, &znode, &n);
1818 if (!found) {
1819 err = -ENOENT;
1820 goto out_unlock;
1821 } else if (found < 0) {
1822 err = found;
1823 goto out_unlock;
1824 }
1825
1826 ubifs_assert(n >= 0);
1827
1828 err = resolve_collision(c, key, &znode, &n, nm);
1829 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
1830 if (unlikely(err < 0))
1831 goto out_unlock;
1832 if (err == 0) {
1833 err = -ENOENT;
1834 goto out_unlock;
1835 }
1836
1837 err = tnc_read_node_nm(c, &znode->zbranch[n], node);
1838
1839out_unlock:
1840 mutex_unlock(&c->tnc_mutex);
1841 return err;
1842}
1843
1844/**
1845 * ubifs_tnc_lookup_nm - look up a "hashed" node.
1846 * @c: UBIFS file-system description object
1847 * @key: node key to lookup
1848 * @node: the node is returned here
1849 * @nm: node name
1850 *
1851 * This function look up and reads a node which contains name hash in the key.
1852 * Since the hash may have collisions, there may be many nodes with the same
1853 * key, so we have to sequentially look to all of them until the needed one is
1854 * found. This function returns zero in case of success, %-ENOENT if the node
1855 * was not found, and a negative error code in case of failure.
1856 */
1857int ubifs_tnc_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1858 void *node, const struct qstr *nm)
1859{
1860 int err, len;
1861 const struct ubifs_dent_node *dent = node;
1862
1863 /*
1864 * We assume that in most of the cases there are no name collisions and
1865 * 'ubifs_tnc_lookup()' returns us the right direntry.
1866 */
1867 err = ubifs_tnc_lookup(c, key, node);
1868 if (err)
1869 return err;
1870
1871 len = le16_to_cpu(dent->nlen);
1872 if (nm->len == len && !memcmp(dent->name, nm->name, len))
1873 return 0;
1874
1875 /*
1876 * Unluckily, there are hash collisions and we have to iterate over
1877 * them look at each direntry with colliding name hash sequentially.
1878 */
1879 return do_lookup_nm(c, key, node, nm);
1880}
1881
1882/**
1883 * correct_parent_keys - correct parent znodes' keys.
1884 * @c: UBIFS file-system description object
1885 * @znode: znode to correct parent znodes for
1886 *
1887 * This is a helper function for 'tnc_insert()'. When the key of the leftmost
1888 * zbranch changes, keys of parent znodes have to be corrected. This helper
1889 * function is called in such situations and corrects the keys if needed.
1890 */
1891static void correct_parent_keys(const struct ubifs_info *c,
1892 struct ubifs_znode *znode)
1893{
1894 union ubifs_key *key, *key1;
1895
1896 ubifs_assert(znode->parent);
1897 ubifs_assert(znode->iip == 0);
1898
1899 key = &znode->zbranch[0].key;
1900 key1 = &znode->parent->zbranch[0].key;
1901
1902 while (keys_cmp(c, key, key1) < 0) {
1903 key_copy(c, key, key1);
1904 znode = znode->parent;
1905 znode->alt = 1;
1906 if (!znode->parent || znode->iip)
1907 break;
1908 key1 = &znode->parent->zbranch[0].key;
1909 }
1910}
1911
1912/**
1913 * insert_zbranch - insert a zbranch into a znode.
1914 * @znode: znode into which to insert
1915 * @zbr: zbranch to insert
1916 * @n: slot number to insert to
1917 *
1918 * This is a helper function for 'tnc_insert()'. UBIFS does not allow "gaps" in
1919 * znode's array of zbranches and keeps zbranches consolidated, so when a new
1920 * zbranch has to be inserted to the @znode->zbranches[]' array at the @n-th
1921 * slot, zbranches starting from @n have to be moved right.
1922 */
1923static void insert_zbranch(struct ubifs_znode *znode,
1924 const struct ubifs_zbranch *zbr, int n)
1925{
1926 int i;
1927
1928 ubifs_assert(ubifs_zn_dirty(znode));
1929
1930 if (znode->level) {
1931 for (i = znode->child_cnt; i > n; i--) {
1932 znode->zbranch[i] = znode->zbranch[i - 1];
1933 if (znode->zbranch[i].znode)
1934 znode->zbranch[i].znode->iip = i;
1935 }
1936 if (zbr->znode)
1937 zbr->znode->iip = n;
1938 } else
1939 for (i = znode->child_cnt; i > n; i--)
1940 znode->zbranch[i] = znode->zbranch[i - 1];
1941
1942 znode->zbranch[n] = *zbr;
1943 znode->child_cnt += 1;
1944
1945 /*
1946 * After inserting at slot zero, the lower bound of the key range of
1947 * this znode may have changed. If this znode is subsequently split
1948 * then the upper bound of the key range may change, and furthermore
1949 * it could change to be lower than the original lower bound. If that
1950 * happens, then it will no longer be possible to find this znode in the
1951 * TNC using the key from the index node on flash. That is bad because
1952 * if it is not found, we will assume it is obsolete and may overwrite
1953 * it. Then if there is an unclean unmount, we will start using the
1954 * old index which will be broken.
1955 *
1956 * So we first mark znodes that have insertions at slot zero, and then
1957 * if they are split we add their lnum/offs to the old_idx tree.
1958 */
1959 if (n == 0)
1960 znode->alt = 1;
1961}
1962
1963/**
1964 * tnc_insert - insert a node into TNC.
1965 * @c: UBIFS file-system description object
1966 * @znode: znode to insert into
1967 * @zbr: branch to insert
1968 * @n: slot number to insert new zbranch to
1969 *
1970 * This function inserts a new node described by @zbr into znode @znode. If
1971 * znode does not have a free slot for new zbranch, it is split. Parent znodes
1972 * are splat as well if needed. Returns zero in case of success or a negative
1973 * error code in case of failure.
1974 */
1975static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode,
1976 struct ubifs_zbranch *zbr, int n)
1977{
1978 struct ubifs_znode *zn, *zi, *zp;
1979 int i, keep, move, appending = 0;
1980 union ubifs_key *key = &zbr->key, *key1;
1981
1982 ubifs_assert(n >= 0 && n <= c->fanout);
1983
1984 /* Implement naive insert for now */
1985again:
1986 zp = znode->parent;
1987 if (znode->child_cnt < c->fanout) {
1988 ubifs_assert(n != c->fanout);
1989 dbg_tnc("inserted at %d level %d, key %s", n, znode->level,
1990 DBGKEY(key));
1991
1992 insert_zbranch(znode, zbr, n);
1993
1994 /* Ensure parent's key is correct */
1995 if (n == 0 && zp && znode->iip == 0)
1996 correct_parent_keys(c, znode);
1997
1998 return 0;
1999 }
2000
2001 /*
2002 * Unfortunately, @znode does not have more empty slots and we have to
2003 * split it.
2004 */
2005 dbg_tnc("splitting level %d, key %s", znode->level, DBGKEY(key));
2006
2007 if (znode->alt)
2008 /*
2009 * We can no longer be sure of finding this znode by key, so we
2010 * record it in the old_idx tree.
2011 */
2012 ins_clr_old_idx_znode(c, znode);
2013
2014 zn = kzalloc(c->max_znode_sz, GFP_NOFS);
2015 if (!zn)
2016 return -ENOMEM;
2017 zn->parent = zp;
2018 zn->level = znode->level;
2019
2020 /* Decide where to split */
2021 if (znode->level == 0 && key_type(c, key) == UBIFS_DATA_KEY) {
2022 /* Try not to split consecutive data keys */
2023 if (n == c->fanout) {
2024 key1 = &znode->zbranch[n - 1].key;
2025 if (key_inum(c, key1) == key_inum(c, key) &&
2026 key_type(c, key1) == UBIFS_DATA_KEY)
2027 appending = 1;
2028 } else
2029 goto check_split;
2030 } else if (appending && n != c->fanout) {
2031 /* Try not to split consecutive data keys */
2032 appending = 0;
2033check_split:
2034 if (n >= (c->fanout + 1) / 2) {
2035 key1 = &znode->zbranch[0].key;
2036 if (key_inum(c, key1) == key_inum(c, key) &&
2037 key_type(c, key1) == UBIFS_DATA_KEY) {
2038 key1 = &znode->zbranch[n].key;
2039 if (key_inum(c, key1) != key_inum(c, key) ||
2040 key_type(c, key1) != UBIFS_DATA_KEY) {
2041 keep = n;
2042 move = c->fanout - keep;
2043 zi = znode;
2044 goto do_split;
2045 }
2046 }
2047 }
2048 }
2049
2050 if (appending) {
2051 keep = c->fanout;
2052 move = 0;
2053 } else {
2054 keep = (c->fanout + 1) / 2;
2055 move = c->fanout - keep;
2056 }
2057
2058 /*
2059 * Although we don't at present, we could look at the neighbors and see
2060 * if we can move some zbranches there.
2061 */
2062
2063 if (n < keep) {
2064 /* Insert into existing znode */
2065 zi = znode;
2066 move += 1;
2067 keep -= 1;
2068 } else {
2069 /* Insert into new znode */
2070 zi = zn;
2071 n -= keep;
2072 /* Re-parent */
2073 if (zn->level != 0)
2074 zbr->znode->parent = zn;
2075 }
2076
2077do_split:
2078
2079 __set_bit(DIRTY_ZNODE, &zn->flags);
2080 atomic_long_inc(&c->dirty_zn_cnt);
2081
2082 zn->child_cnt = move;
2083 znode->child_cnt = keep;
2084
2085 dbg_tnc("moving %d, keeping %d", move, keep);
2086
2087 /* Move zbranch */
2088 for (i = 0; i < move; i++) {
2089 zn->zbranch[i] = znode->zbranch[keep + i];
2090 /* Re-parent */
2091 if (zn->level != 0)
2092 if (zn->zbranch[i].znode) {
2093 zn->zbranch[i].znode->parent = zn;
2094 zn->zbranch[i].znode->iip = i;
2095 }
2096 }
2097
2098 /* Insert new key and branch */
2099 dbg_tnc("inserting at %d level %d, key %s", n, zn->level, DBGKEY(key));
2100
2101 insert_zbranch(zi, zbr, n);
2102
2103 /* Insert new znode (produced by spitting) into the parent */
2104 if (zp) {
2105 if (n == 0 && zi == znode && znode->iip == 0)
2106 correct_parent_keys(c, znode);
2107
2108 /* Locate insertion point */
2109 n = znode->iip + 1;
2110
2111 /* Tail recursion */
2112 zbr->key = zn->zbranch[0].key;
2113 zbr->znode = zn;
2114 zbr->lnum = 0;
2115 zbr->offs = 0;
2116 zbr->len = 0;
2117 znode = zp;
2118
2119 goto again;
2120 }
2121
2122 /* We have to split root znode */
2123 dbg_tnc("creating new zroot at level %d", znode->level + 1);
2124
2125 zi = kzalloc(c->max_znode_sz, GFP_NOFS);
2126 if (!zi)
2127 return -ENOMEM;
2128
2129 zi->child_cnt = 2;
2130 zi->level = znode->level + 1;
2131
2132 __set_bit(DIRTY_ZNODE, &zi->flags);
2133 atomic_long_inc(&c->dirty_zn_cnt);
2134
2135 zi->zbranch[0].key = znode->zbranch[0].key;
2136 zi->zbranch[0].znode = znode;
2137 zi->zbranch[0].lnum = c->zroot.lnum;
2138 zi->zbranch[0].offs = c->zroot.offs;
2139 zi->zbranch[0].len = c->zroot.len;
2140 zi->zbranch[1].key = zn->zbranch[0].key;
2141 zi->zbranch[1].znode = zn;
2142
2143 c->zroot.lnum = 0;
2144 c->zroot.offs = 0;
2145 c->zroot.len = 0;
2146 c->zroot.znode = zi;
2147
2148 zn->parent = zi;
2149 zn->iip = 1;
2150 znode->parent = zi;
2151 znode->iip = 0;
2152
2153 return 0;
2154}
2155
2156/**
2157 * ubifs_tnc_add - add a node to TNC.
2158 * @c: UBIFS file-system description object
2159 * @key: key to add
2160 * @lnum: LEB number of node
2161 * @offs: node offset
2162 * @len: node length
2163 *
2164 * This function adds a node with key @key to TNC. The node may be new or it may
2165 * obsolete some existing one. Returns %0 on success or negative error code on
2166 * failure.
2167 */
2168int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum,
2169 int offs, int len)
2170{
2171 int found, n, err = 0;
2172 struct ubifs_znode *znode;
2173
2174 mutex_lock(&c->tnc_mutex);
2175 dbg_tnc("%d:%d, len %d, key %s", lnum, offs, len, DBGKEY(key));
2176 found = lookup_level0_dirty(c, key, &znode, &n);
2177 if (!found) {
2178 struct ubifs_zbranch zbr;
2179
2180 zbr.znode = NULL;
2181 zbr.lnum = lnum;
2182 zbr.offs = offs;
2183 zbr.len = len;
2184 key_copy(c, key, &zbr.key);
2185 err = tnc_insert(c, znode, &zbr, n + 1);
2186 } else if (found == 1) {
2187 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2188
2189 lnc_free(zbr);
2190 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2191 zbr->lnum = lnum;
2192 zbr->offs = offs;
2193 zbr->len = len;
2194 } else
2195 err = found;
2196 if (!err)
2197 err = dbg_check_tnc(c, 0);
2198 mutex_unlock(&c->tnc_mutex);
2199
2200 return err;
2201}
2202
2203/**
2204 * ubifs_tnc_replace - replace a node in the TNC only if the old node is found.
2205 * @c: UBIFS file-system description object
2206 * @key: key to add
2207 * @old_lnum: LEB number of old node
2208 * @old_offs: old node offset
2209 * @lnum: LEB number of node
2210 * @offs: node offset
2211 * @len: node length
2212 *
2213 * This function replaces a node with key @key in the TNC only if the old node
2214 * is found. This function is called by garbage collection when node are moved.
2215 * Returns %0 on success or negative error code on failure.
2216 */
2217int ubifs_tnc_replace(struct ubifs_info *c, const union ubifs_key *key,
2218 int old_lnum, int old_offs, int lnum, int offs, int len)
2219{
2220 int found, n, err = 0;
2221 struct ubifs_znode *znode;
2222
2223 mutex_lock(&c->tnc_mutex);
2224 dbg_tnc("old LEB %d:%d, new LEB %d:%d, len %d, key %s", old_lnum,
2225 old_offs, lnum, offs, len, DBGKEY(key));
2226 found = lookup_level0_dirty(c, key, &znode, &n);
2227 if (found < 0) {
2228 err = found;
2229 goto out_unlock;
2230 }
2231
2232 if (found == 1) {
2233 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2234
2235 found = 0;
2236 if (zbr->lnum == old_lnum && zbr->offs == old_offs) {
2237 lnc_free(zbr);
2238 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2239 if (err)
2240 goto out_unlock;
2241 zbr->lnum = lnum;
2242 zbr->offs = offs;
2243 zbr->len = len;
2244 found = 1;
2245 } else if (is_hash_key(c, key)) {
2246 found = resolve_collision_directly(c, key, &znode, &n,
2247 old_lnum, old_offs);
2248 dbg_tnc("rc returned %d, znode %p, n %d, LEB %d:%d",
2249 found, znode, n, old_lnum, old_offs);
2250 if (found < 0) {
2251 err = found;
2252 goto out_unlock;
2253 }
2254
2255 if (found) {
2256 /* Ensure the znode is dirtied */
2257 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2258 znode = dirty_cow_bottom_up(c, znode);
2259 if (IS_ERR(znode)) {
2260 err = PTR_ERR(znode);
2261 goto out_unlock;
2262 }
2263 }
2264 zbr = &znode->zbranch[n];
2265 lnc_free(zbr);
2266 err = ubifs_add_dirt(c, zbr->lnum,
2267 zbr->len);
2268 if (err)
2269 goto out_unlock;
2270 zbr->lnum = lnum;
2271 zbr->offs = offs;
2272 zbr->len = len;
2273 }
2274 }
2275 }
2276
2277 if (!found)
2278 err = ubifs_add_dirt(c, lnum, len);
2279
2280 if (!err)
2281 err = dbg_check_tnc(c, 0);
2282
2283out_unlock:
2284 mutex_unlock(&c->tnc_mutex);
2285 return err;
2286}
2287
2288/**
2289 * ubifs_tnc_add_nm - add a "hashed" node to TNC.
2290 * @c: UBIFS file-system description object
2291 * @key: key to add
2292 * @lnum: LEB number of node
2293 * @offs: node offset
2294 * @len: node length
2295 * @nm: node name
2296 *
2297 * This is the same as 'ubifs_tnc_add()' but it should be used with keys which
2298 * may have collisions, like directory entry keys.
2299 */
2300int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
2301 int lnum, int offs, int len, const struct qstr *nm)
2302{
2303 int found, n, err = 0;
2304 struct ubifs_znode *znode;
2305
2306 mutex_lock(&c->tnc_mutex);
2307 dbg_tnc("LEB %d:%d, name '%.*s', key %s", lnum, offs, nm->len, nm->name,
2308 DBGKEY(key));
2309 found = lookup_level0_dirty(c, key, &znode, &n);
2310 if (found < 0) {
2311 err = found;
2312 goto out_unlock;
2313 }
2314
2315 if (found == 1) {
2316 if (c->replaying)
2317 found = fallible_resolve_collision(c, key, &znode, &n,
2318 nm, 1);
2319 else
2320 found = resolve_collision(c, key, &znode, &n, nm);
2321 dbg_tnc("rc returned %d, znode %p, n %d", found, znode, n);
2322 if (found < 0) {
2323 err = found;
2324 goto out_unlock;
2325 }
2326
2327 /* Ensure the znode is dirtied */
2328 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2329 znode = dirty_cow_bottom_up(c, znode);
2330 if (IS_ERR(znode)) {
2331 err = PTR_ERR(znode);
2332 goto out_unlock;
2333 }
2334 }
2335
2336 if (found == 1) {
2337 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2338
2339 lnc_free(zbr);
2340 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2341 zbr->lnum = lnum;
2342 zbr->offs = offs;
2343 zbr->len = len;
2344 goto out_unlock;
2345 }
2346 }
2347
2348 if (!found) {
2349 struct ubifs_zbranch zbr;
2350
2351 zbr.znode = NULL;
2352 zbr.lnum = lnum;
2353 zbr.offs = offs;
2354 zbr.len = len;
2355 key_copy(c, key, &zbr.key);
2356 err = tnc_insert(c, znode, &zbr, n + 1);
2357 if (err)
2358 goto out_unlock;
2359 if (c->replaying) {
2360 /*
2361 * We did not find it in the index so there may be a
2362 * dangling branch still in the index. So we remove it
2363 * by passing 'ubifs_tnc_remove_nm()' the same key but
2364 * an unmatchable name.
2365 */
2366 struct qstr noname = { .len = 0, .name = "" };
2367
2368 err = dbg_check_tnc(c, 0);
2369 mutex_unlock(&c->tnc_mutex);
2370 if (err)
2371 return err;
2372 return ubifs_tnc_remove_nm(c, key, &noname);
2373 }
2374 }
2375
2376out_unlock:
2377 if (!err)
2378 err = dbg_check_tnc(c, 0);
2379 mutex_unlock(&c->tnc_mutex);
2380 return err;
2381}
2382
2383/**
2384 * tnc_delete - delete a znode form TNC.
2385 * @c: UBIFS file-system description object
2386 * @znode: znode to delete from
2387 * @n: zbranch slot number to delete
2388 *
2389 * This function deletes a leaf node from @n-th slot of @znode. Returns zero in
2390 * case of success and a negative error code in case of failure.
2391 */
2392static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n)
2393{
2394 struct ubifs_zbranch *zbr;
2395 struct ubifs_znode *zp;
2396 int i, err;
2397
2398 /* Delete without merge for now */
2399 ubifs_assert(znode->level == 0);
2400 ubifs_assert(n >= 0 && n < c->fanout);
2401 dbg_tnc("deleting %s", DBGKEY(&znode->zbranch[n].key));
2402
2403 zbr = &znode->zbranch[n];
2404 lnc_free(zbr);
2405
2406 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2407 if (err) {
2408 dbg_dump_znode(c, znode);
2409 return err;
2410 }
2411
2412 /* We do not "gap" zbranch slots */
2413 for (i = n; i < znode->child_cnt - 1; i++)
2414 znode->zbranch[i] = znode->zbranch[i + 1];
2415 znode->child_cnt -= 1;
2416
2417 if (znode->child_cnt > 0)
2418 return 0;
2419
2420 /*
2421 * This was the last zbranch, we have to delete this znode from the
2422 * parent.
2423 */
2424
2425 do {
2426 ubifs_assert(!ubifs_zn_obsolete(znode));
2427 ubifs_assert(ubifs_zn_dirty(znode));
2428
2429 zp = znode->parent;
2430 n = znode->iip;
2431
2432 atomic_long_dec(&c->dirty_zn_cnt);
2433
2434 err = insert_old_idx_znode(c, znode);
2435 if (err)
2436 return err;
2437
2438 if (znode->cnext) {
2439 __set_bit(OBSOLETE_ZNODE, &znode->flags);
2440 atomic_long_inc(&c->clean_zn_cnt);
2441 atomic_long_inc(&ubifs_clean_zn_cnt);
2442 } else
2443 kfree(znode);
2444 znode = zp;
2445 } while (znode->child_cnt == 1); /* while removing last child */
2446
2447 /* Remove from znode, entry n - 1 */
2448 znode->child_cnt -= 1;
2449 ubifs_assert(znode->level != 0);
2450 for (i = n; i < znode->child_cnt; i++) {
2451 znode->zbranch[i] = znode->zbranch[i + 1];
2452 if (znode->zbranch[i].znode)
2453 znode->zbranch[i].znode->iip = i;
2454 }
2455
2456 /*
2457 * If this is the root and it has only 1 child then
2458 * collapse the tree.
2459 */
2460 if (!znode->parent) {
2461 while (znode->child_cnt == 1 && znode->level != 0) {
2462 zp = znode;
2463 zbr = &znode->zbranch[0];
2464 znode = get_znode(c, znode, 0);
2465 if (IS_ERR(znode))
2466 return PTR_ERR(znode);
2467 znode = dirty_cow_znode(c, zbr);
2468 if (IS_ERR(znode))
2469 return PTR_ERR(znode);
2470 znode->parent = NULL;
2471 znode->iip = 0;
2472 if (c->zroot.len) {
2473 err = insert_old_idx(c, c->zroot.lnum,
2474 c->zroot.offs);
2475 if (err)
2476 return err;
2477 }
2478 c->zroot.lnum = zbr->lnum;
2479 c->zroot.offs = zbr->offs;
2480 c->zroot.len = zbr->len;
2481 c->zroot.znode = znode;
2482 ubifs_assert(!ubifs_zn_obsolete(zp));
2483 ubifs_assert(ubifs_zn_dirty(zp));
2484 atomic_long_dec(&c->dirty_zn_cnt);
2485
2486 if (zp->cnext) {
2487 __set_bit(OBSOLETE_ZNODE, &zp->flags);
2488 atomic_long_inc(&c->clean_zn_cnt);
2489 atomic_long_inc(&ubifs_clean_zn_cnt);
2490 } else
2491 kfree(zp);
2492 }
2493 }
2494
2495 return 0;
2496}
2497
2498/**
2499 * ubifs_tnc_remove - remove an index entry of a node.
2500 * @c: UBIFS file-system description object
2501 * @key: key of node
2502 *
2503 * Returns %0 on success or negative error code on failure.
2504 */
2505int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key)
2506{
2507 int found, n, err = 0;
2508 struct ubifs_znode *znode;
2509
2510 mutex_lock(&c->tnc_mutex);
2511 dbg_tnc("key %s", DBGKEY(key));
2512 found = lookup_level0_dirty(c, key, &znode, &n);
2513 if (found < 0) {
2514 err = found;
2515 goto out_unlock;
2516 }
2517 if (found == 1)
2518 err = tnc_delete(c, znode, n);
2519 if (!err)
2520 err = dbg_check_tnc(c, 0);
2521
2522out_unlock:
2523 mutex_unlock(&c->tnc_mutex);
2524 return err;
2525}
2526
2527/**
2528 * ubifs_tnc_remove_nm - remove an index entry for a "hashed" node.
2529 * @c: UBIFS file-system description object
2530 * @key: key of node
2531 * @nm: directory entry name
2532 *
2533 * Returns %0 on success or negative error code on failure.
2534 */
2535int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
2536 const struct qstr *nm)
2537{
2538 int n, err;
2539 struct ubifs_znode *znode;
2540
2541 mutex_lock(&c->tnc_mutex);
2542 dbg_tnc("%.*s, key %s", nm->len, nm->name, DBGKEY(key));
2543 err = lookup_level0_dirty(c, key, &znode, &n);
2544 if (err < 0)
2545 goto out_unlock;
2546
2547 if (err) {
2548 if (c->replaying)
2549 err = fallible_resolve_collision(c, key, &znode, &n,
2550 nm, 0);
2551 else
2552 err = resolve_collision(c, key, &znode, &n, nm);
2553 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
2554 if (err < 0)
2555 goto out_unlock;
2556 if (err) {
2557 /* Ensure the znode is dirtied */
2558 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2559 znode = dirty_cow_bottom_up(c, znode);
2560 if (IS_ERR(znode)) {
2561 err = PTR_ERR(znode);
2562 goto out_unlock;
2563 }
2564 }
2565 err = tnc_delete(c, znode, n);
2566 }
2567 }
2568
2569out_unlock:
2570 if (!err)
2571 err = dbg_check_tnc(c, 0);
2572 mutex_unlock(&c->tnc_mutex);
2573 return err;
2574}
2575
2576/**
2577 * key_in_range - determine if a key falls within a range of keys.
2578 * @c: UBIFS file-system description object
2579 * @key: key to check
2580 * @from_key: lowest key in range
2581 * @to_key: highest key in range
2582 *
2583 * This function returns %1 if the key is in range and %0 otherwise.
2584 */
2585static int key_in_range(struct ubifs_info *c, union ubifs_key *key,
2586 union ubifs_key *from_key, union ubifs_key *to_key)
2587{
2588 if (keys_cmp(c, key, from_key) < 0)
2589 return 0;
2590 if (keys_cmp(c, key, to_key) > 0)
2591 return 0;
2592 return 1;
2593}
2594
2595/**
2596 * ubifs_tnc_remove_range - remove index entries in range.
2597 * @c: UBIFS file-system description object
2598 * @from_key: lowest key to remove
2599 * @to_key: highest key to remove
2600 *
2601 * This function removes index entries starting at @from_key and ending at
2602 * @to_key. This function returns zero in case of success and a negative error
2603 * code in case of failure.
2604 */
2605int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key,
2606 union ubifs_key *to_key)
2607{
2608 int i, n, k, err = 0;
2609 struct ubifs_znode *znode;
2610 union ubifs_key *key;
2611
2612 mutex_lock(&c->tnc_mutex);
2613 while (1) {
2614 /* Find first level 0 znode that contains keys to remove */
2615 err = ubifs_lookup_level0(c, from_key, &znode, &n);
2616 if (err < 0)
2617 goto out_unlock;
2618
2619 if (err)
2620 key = from_key;
2621 else {
2622 err = tnc_next(c, &znode, &n);
2623 if (err == -ENOENT) {
2624 err = 0;
2625 goto out_unlock;
2626 }
2627 if (err < 0)
2628 goto out_unlock;
2629 key = &znode->zbranch[n].key;
2630 if (!key_in_range(c, key, from_key, to_key)) {
2631 err = 0;
2632 goto out_unlock;
2633 }
2634 }
2635
2636 /* Ensure the znode is dirtied */
2637 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2638 znode = dirty_cow_bottom_up(c, znode);
2639 if (IS_ERR(znode)) {
2640 err = PTR_ERR(znode);
2641 goto out_unlock;
2642 }
2643 }
2644
2645 /* Remove all keys in range except the first */
2646 for (i = n + 1, k = 0; i < znode->child_cnt; i++, k++) {
2647 key = &znode->zbranch[i].key;
2648 if (!key_in_range(c, key, from_key, to_key))
2649 break;
2650 lnc_free(&znode->zbranch[i]);
2651 err = ubifs_add_dirt(c, znode->zbranch[i].lnum,
2652 znode->zbranch[i].len);
2653 if (err) {
2654 dbg_dump_znode(c, znode);
2655 goto out_unlock;
2656 }
2657 dbg_tnc("removing %s", DBGKEY(key));
2658 }
2659 if (k) {
2660 for (i = n + 1 + k; i < znode->child_cnt; i++)
2661 znode->zbranch[i - k] = znode->zbranch[i];
2662 znode->child_cnt -= k;
2663 }
2664
2665 /* Now delete the first */
2666 err = tnc_delete(c, znode, n);
2667 if (err)
2668 goto out_unlock;
2669 }
2670
2671out_unlock:
2672 if (!err)
2673 err = dbg_check_tnc(c, 0);
2674 mutex_unlock(&c->tnc_mutex);
2675 return err;
2676}
2677
2678/**
2679 * ubifs_tnc_remove_ino - remove an inode from TNC.
2680 * @c: UBIFS file-system description object
2681 * @inum: inode number to remove
2682 *
2683 * This function remove inode @inum and all the extended attributes associated
2684 * with the anode from TNC and returns zero in case of success or a negative
2685 * error code in case of failure.
2686 */
2687int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum)
2688{
2689 union ubifs_key key1, key2;
2690 struct ubifs_dent_node *xent, *pxent = NULL;
2691 struct qstr nm = { .name = NULL };
2692
2693 dbg_tnc("ino %lu", (unsigned long)inum);
2694
2695 /*
2696 * Walk all extended attribute entries and remove them together with
2697 * corresponding extended attribute inodes.
2698 */
2699 lowest_xent_key(c, &key1, inum);
2700 while (1) {
2701 ino_t xattr_inum;
2702 int err;
2703
2704 xent = ubifs_tnc_next_ent(c, &key1, &nm);
2705 if (IS_ERR(xent)) {
2706 err = PTR_ERR(xent);
2707 if (err == -ENOENT)
2708 break;
2709 return err;
2710 }
2711
2712 xattr_inum = le64_to_cpu(xent->inum);
2713 dbg_tnc("xent '%s', ino %lu", xent->name,
2714 (unsigned long)xattr_inum);
2715
2716 nm.name = xent->name;
2717 nm.len = le16_to_cpu(xent->nlen);
2718 err = ubifs_tnc_remove_nm(c, &key1, &nm);
2719 if (err) {
2720 kfree(xent);
2721 return err;
2722 }
2723
2724 lowest_ino_key(c, &key1, xattr_inum);
2725 highest_ino_key(c, &key2, xattr_inum);
2726 err = ubifs_tnc_remove_range(c, &key1, &key2);
2727 if (err) {
2728 kfree(xent);
2729 return err;
2730 }
2731
2732 kfree(pxent);
2733 pxent = xent;
2734 key_read(c, &xent->key, &key1);
2735 }
2736
2737 kfree(pxent);
2738 lowest_ino_key(c, &key1, inum);
2739 highest_ino_key(c, &key2, inum);
2740
2741 return ubifs_tnc_remove_range(c, &key1, &key2);
2742}
2743
2744/**
2745 * ubifs_tnc_next_ent - walk directory or extended attribute entries.
2746 * @c: UBIFS file-system description object
2747 * @key: key of last entry
2748 * @nm: name of last entry found or %NULL
2749 *
2750 * This function finds and reads the next directory or extended attribute entry
2751 * after the given key (@key) if there is one. @nm is used to resolve
2752 * collisions.
2753 *
2754 * If the name of the current entry is not known and only the key is known,
2755 * @nm->name has to be %NULL. In this case the semantics of this function is a
2756 * little bit different and it returns the entry corresponding to this key, not
2757 * the next one. If the key was not found, the closest "right" entry is
2758 * returned.
2759 *
2760 * If the fist entry has to be found, @key has to contain the lowest possible
2761 * key value for this inode and @name has to be %NULL.
2762 *
2763 * This function returns the found directory or extended attribute entry node
2764 * in case of success, %-ENOENT is returned if no entry was found, and a
2765 * negative error code is returned in case of failure.
2766 */
2767struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c,
2768 union ubifs_key *key,
2769 const struct qstr *nm)
2770{
2771 int n, err, type = key_type(c, key);
2772 struct ubifs_znode *znode;
2773 struct ubifs_dent_node *dent;
2774 struct ubifs_zbranch *zbr;
2775 union ubifs_key *dkey;
2776
2777 dbg_tnc("%s %s", nm->name ? (char *)nm->name : "(lowest)", DBGKEY(key));
2778 ubifs_assert(is_hash_key(c, key));
2779
2780 mutex_lock(&c->tnc_mutex);
2781 err = ubifs_lookup_level0(c, key, &znode, &n);
2782 if (unlikely(err < 0))
2783 goto out_unlock;
2784
2785 if (nm->name) {
2786 if (err) {
2787 /* Handle collisions */
2788 err = resolve_collision(c, key, &znode, &n, nm);
2789 dbg_tnc("rc returned %d, znode %p, n %d",
2790 err, znode, n);
2791 if (unlikely(err < 0))
2792 goto out_unlock;
2793 }
2794
2795 /* Now find next entry */
2796 err = tnc_next(c, &znode, &n);
2797 if (unlikely(err))
2798 goto out_unlock;
2799 } else {
2800 /*
2801 * The full name of the entry was not given, in which case the
2802 * behavior of this function is a little different and it
2803 * returns current entry, not the next one.
2804 */
2805 if (!err) {
2806 /*
2807 * However, the given key does not exist in the TNC
2808 * tree and @znode/@n variables contain the closest
2809 * "preceding" element. Switch to the next one.
2810 */
2811 err = tnc_next(c, &znode, &n);
2812 if (err)
2813 goto out_unlock;
2814 }
2815 }
2816
2817 zbr = &znode->zbranch[n];
2818 dent = kmalloc(zbr->len, GFP_NOFS);
2819 if (unlikely(!dent)) {
2820 err = -ENOMEM;
2821 goto out_unlock;
2822 }
2823
2824 /*
2825 * The above 'tnc_next()' call could lead us to the next inode, check
2826 * this.
2827 */
2828 dkey = &zbr->key;
2829 if (key_inum(c, dkey) != key_inum(c, key) ||
2830 key_type(c, dkey) != type) {
2831 err = -ENOENT;
2832 goto out_free;
2833 }
2834
2835 err = tnc_read_node_nm(c, zbr, dent);
2836 if (unlikely(err))
2837 goto out_free;
2838
2839 mutex_unlock(&c->tnc_mutex);
2840 return dent;
2841
2842out_free:
2843 kfree(dent);
2844out_unlock:
2845 mutex_unlock(&c->tnc_mutex);
2846 return ERR_PTR(err);
2847}
2848
2849/**
2850 * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit.
2851 * @c: UBIFS file-system description object
2852 *
2853 * Destroy left-over obsolete znodes from a failed commit.
2854 */
2855static void tnc_destroy_cnext(struct ubifs_info *c)
2856{
2857 struct ubifs_znode *cnext;
2858
2859 if (!c->cnext)
2860 return;
2861 ubifs_assert(c->cmt_state == COMMIT_BROKEN);
2862 cnext = c->cnext;
2863 do {
2864 struct ubifs_znode *znode = cnext;
2865
2866 cnext = cnext->cnext;
2867 if (ubifs_zn_obsolete(znode))
2868 kfree(znode);
2869 } while (cnext && cnext != c->cnext);
2870}
2871
2872/**
2873 * ubifs_tnc_close - close TNC subsystem and free all related resources.
2874 * @c: UBIFS file-system description object
2875 */
2876void ubifs_tnc_close(struct ubifs_info *c)
2877{
2878 tnc_destroy_cnext(c);
2879 if (c->zroot.znode) {
2880 long n;
2881
2882 ubifs_destroy_tnc_subtree(c->zroot.znode);
2883 n = atomic_long_read(&c->clean_zn_cnt);
2884 atomic_long_sub(n, &ubifs_clean_zn_cnt);
2885 }
2886 kfree(c->gap_lebs);
2887 kfree(c->ilebs);
2888 destroy_old_idx(c);
2889}
2890
2891/**
2892 * left_znode - get the znode to the left.
2893 * @c: UBIFS file-system description object
2894 * @znode: znode
2895 *
2896 * This function returns a pointer to the znode to the left of @znode or NULL if
2897 * there is not one. A negative error code is returned on failure.
2898 */
2899static struct ubifs_znode *left_znode(struct ubifs_info *c,
2900 struct ubifs_znode *znode)
2901{
2902 int level = znode->level;
2903
2904 while (1) {
2905 int n = znode->iip - 1;
2906
2907 /* Go up until we can go left */
2908 znode = znode->parent;
2909 if (!znode)
2910 return NULL;
2911 if (n >= 0) {
2912 /* Now go down the rightmost branch to 'level' */
2913 znode = get_znode(c, znode, n);
2914 if (IS_ERR(znode))
2915 return znode;
2916 while (znode->level != level) {
2917 n = znode->child_cnt - 1;
2918 znode = get_znode(c, znode, n);
2919 if (IS_ERR(znode))
2920 return znode;
2921 }
2922 break;
2923 }
2924 }
2925 return znode;
2926}
2927
2928/**
2929 * right_znode - get the znode to the right.
2930 * @c: UBIFS file-system description object
2931 * @znode: znode
2932 *
2933 * This function returns a pointer to the znode to the right of @znode or NULL
2934 * if there is not one. A negative error code is returned on failure.
2935 */
2936static struct ubifs_znode *right_znode(struct ubifs_info *c,
2937 struct ubifs_znode *znode)
2938{
2939 int level = znode->level;
2940
2941 while (1) {
2942 int n = znode->iip + 1;
2943
2944 /* Go up until we can go right */
2945 znode = znode->parent;
2946 if (!znode)
2947 return NULL;
2948 if (n < znode->child_cnt) {
2949 /* Now go down the leftmost branch to 'level' */
2950 znode = get_znode(c, znode, n);
2951 if (IS_ERR(znode))
2952 return znode;
2953 while (znode->level != level) {
2954 znode = get_znode(c, znode, 0);
2955 if (IS_ERR(znode))
2956 return znode;
2957 }
2958 break;
2959 }
2960 }
2961 return znode;
2962}
2963
2964/**
2965 * lookup_znode - find a particular indexing node from TNC.
2966 * @c: UBIFS file-system description object
2967 * @key: index node key to lookup
2968 * @level: index node level
2969 * @lnum: index node LEB number
2970 * @offs: index node offset
2971 *
2972 * This function searches an indexing node by its first key @key and its
2973 * address @lnum:@offs. It looks up the indexing tree by pulling all indexing
2974 * nodes it traverses to TNC. This function is called for indexing nodes which
2975 * were found on the media by scanning, for example when garbage-collecting or
2976 * when doing in-the-gaps commit. This means that the indexing node which is
2977 * looked for does not have to have exactly the same leftmost key @key, because
2978 * the leftmost key may have been changed, in which case TNC will contain a
2979 * dirty znode which still refers the same @lnum:@offs. This function is clever
2980 * enough to recognize such indexing nodes.
2981 *
2982 * Note, if a znode was deleted or changed too much, then this function will
2983 * not find it. For situations like this UBIFS has the old index RB-tree
2984 * (indexed by @lnum:@offs).
2985 *
2986 * This function returns a pointer to the znode found or %NULL if it is not
2987 * found. A negative error code is returned on failure.
2988 */
2989static struct ubifs_znode *lookup_znode(struct ubifs_info *c,
2990 union ubifs_key *key, int level,
2991 int lnum, int offs)
2992{
2993 struct ubifs_znode *znode, *zn;
2994 int n, nn;
2995
2996 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
2997
2998 /*
2999 * The arguments have probably been read off flash, so don't assume
3000 * they are valid.
3001 */
3002 if (level < 0)
3003 return ERR_PTR(-EINVAL);
3004
3005 /* Get the root znode */
3006 znode = c->zroot.znode;
3007 if (!znode) {
3008 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
3009 if (IS_ERR(znode))
3010 return znode;
3011 }
3012 /* Check if it is the one we are looking for */
3013 if (c->zroot.lnum == lnum && c->zroot.offs == offs)
3014 return znode;
3015 /* Descend to the parent level i.e. (level + 1) */
3016 if (level >= znode->level)
3017 return NULL;
3018 while (1) {
3019 ubifs_search_zbranch(c, znode, key, &n);
3020 if (n < 0) {
3021 /*
3022 * We reached a znode where the leftmost key is greater
3023 * than the key we are searching for. This is the same
3024 * situation as the one described in a huge comment at
3025 * the end of the 'ubifs_lookup_level0()' function. And
3026 * for exactly the same reasons we have to try to look
3027 * left before giving up.
3028 */
3029 znode = left_znode(c, znode);
3030 if (!znode)
3031 return NULL;
3032 if (IS_ERR(znode))
3033 return znode;
3034 ubifs_search_zbranch(c, znode, key, &n);
3035 ubifs_assert(n >= 0);
3036 }
3037 if (znode->level == level + 1)
3038 break;
3039 znode = get_znode(c, znode, n);
3040 if (IS_ERR(znode))
3041 return znode;
3042 }
3043 /* Check if the child is the one we are looking for */
3044 if (znode->zbranch[n].lnum == lnum && znode->zbranch[n].offs == offs)
3045 return get_znode(c, znode, n);
3046 /* If the key is unique, there is nowhere else to look */
3047 if (!is_hash_key(c, key))
3048 return NULL;
3049 /*
3050 * The key is not unique and so may be also in the znodes to either
3051 * side.
3052 */
3053 zn = znode;
3054 nn = n;
3055 /* Look left */
3056 while (1) {
3057 /* Move one branch to the left */
3058 if (n)
3059 n -= 1;
3060 else {
3061 znode = left_znode(c, znode);
3062 if (!znode)
3063 break;
3064 if (IS_ERR(znode))
3065 return znode;
3066 n = znode->child_cnt - 1;
3067 }
3068 /* Check it */
3069 if (znode->zbranch[n].lnum == lnum &&
3070 znode->zbranch[n].offs == offs)
3071 return get_znode(c, znode, n);
3072 /* Stop if the key is less than the one we are looking for */
3073 if (keys_cmp(c, &znode->zbranch[n].key, key) < 0)
3074 break;
3075 }
3076 /* Back to the middle */
3077 znode = zn;
3078 n = nn;
3079 /* Look right */
3080 while (1) {
3081 /* Move one branch to the right */
3082 if (++n >= znode->child_cnt) {
3083 znode = right_znode(c, znode);
3084 if (!znode)
3085 break;
3086 if (IS_ERR(znode))
3087 return znode;
3088 n = 0;
3089 }
3090 /* Check it */
3091 if (znode->zbranch[n].lnum == lnum &&
3092 znode->zbranch[n].offs == offs)
3093 return get_znode(c, znode, n);
3094 /* Stop if the key is greater than the one we are looking for */
3095 if (keys_cmp(c, &znode->zbranch[n].key, key) > 0)
3096 break;
3097 }
3098 return NULL;
3099}
3100
3101/**
3102 * is_idx_node_in_tnc - determine if an index node is in the TNC.
3103 * @c: UBIFS file-system description object
3104 * @key: key of index node
3105 * @level: index node level
3106 * @lnum: LEB number of index node
3107 * @offs: offset of index node
3108 *
3109 * This function returns %0 if the index node is not referred to in the TNC, %1
3110 * if the index node is referred to in the TNC and the corresponding znode is
3111 * dirty, %2 if an index node is referred to in the TNC and the corresponding
3112 * znode is clean, and a negative error code in case of failure.
3113 *
3114 * Note, the @key argument has to be the key of the first child. Also note,
3115 * this function relies on the fact that 0:0 is never a valid LEB number and
3116 * offset for a main-area node.
3117 */
3118int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level,
3119 int lnum, int offs)
3120{
3121 struct ubifs_znode *znode;
3122
3123 znode = lookup_znode(c, key, level, lnum, offs);
3124 if (!znode)
3125 return 0;
3126 if (IS_ERR(znode))
3127 return PTR_ERR(znode);
3128
3129 return ubifs_zn_dirty(znode) ? 1 : 2;
3130}
3131
3132/**
3133 * is_leaf_node_in_tnc - determine if a non-indexing not is in the TNC.
3134 * @c: UBIFS file-system description object
3135 * @key: node key
3136 * @lnum: node LEB number
3137 * @offs: node offset
3138 *
3139 * This function returns %1 if the node is referred to in the TNC, %0 if it is
3140 * not, and a negative error code in case of failure.
3141 *
3142 * Note, this function relies on the fact that 0:0 is never a valid LEB number
3143 * and offset for a main-area node.
3144 */
3145static int is_leaf_node_in_tnc(struct ubifs_info *c, union ubifs_key *key,
3146 int lnum, int offs)
3147{
3148 struct ubifs_zbranch *zbr;
3149 struct ubifs_znode *znode, *zn;
3150 int n, found, err, nn;
3151 const int unique = !is_hash_key(c, key);
3152
3153 found = ubifs_lookup_level0(c, key, &znode, &n);
3154 if (found < 0)
3155 return found; /* Error code */
3156 if (!found)
3157 return 0;
3158 zbr = &znode->zbranch[n];
3159 if (lnum == zbr->lnum && offs == zbr->offs)
3160 return 1; /* Found it */
3161 if (unique)
3162 return 0;
3163 /*
3164 * Because the key is not unique, we have to look left
3165 * and right as well
3166 */
3167 zn = znode;
3168 nn = n;
3169 /* Look left */
3170 while (1) {
3171 err = tnc_prev(c, &znode, &n);
3172 if (err == -ENOENT)
3173 break;
3174 if (err)
3175 return err;
3176 if (keys_cmp(c, key, &znode->zbranch[n].key))
3177 break;
3178 zbr = &znode->zbranch[n];
3179 if (lnum == zbr->lnum && offs == zbr->offs)
3180 return 1; /* Found it */
3181 }
3182 /* Look right */
3183 znode = zn;
3184 n = nn;
3185 while (1) {
3186 err = tnc_next(c, &znode, &n);
3187 if (err) {
3188 if (err == -ENOENT)
3189 return 0;
3190 return err;
3191 }
3192 if (keys_cmp(c, key, &znode->zbranch[n].key))
3193 break;
3194 zbr = &znode->zbranch[n];
3195 if (lnum == zbr->lnum && offs == zbr->offs)
3196 return 1; /* Found it */
3197 }
3198 return 0;
3199}
3200
3201/**
3202 * ubifs_tnc_has_node - determine whether a node is in the TNC.
3203 * @c: UBIFS file-system description object
3204 * @key: node key
3205 * @level: index node level (if it is an index node)
3206 * @lnum: node LEB number
3207 * @offs: node offset
3208 * @is_idx: non-zero if the node is an index node
3209 *
3210 * This function returns %1 if the node is in the TNC, %0 if it is not, and a
3211 * negative error code in case of failure. For index nodes, @key has to be the
3212 * key of the first child. An index node is considered to be in the TNC only if
3213 * the corresponding znode is clean or has not been loaded.
3214 */
3215int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level,
3216 int lnum, int offs, int is_idx)
3217{
3218 int err;
3219
3220 mutex_lock(&c->tnc_mutex);
3221 if (is_idx) {
3222 err = is_idx_node_in_tnc(c, key, level, lnum, offs);
3223 if (err < 0)
3224 goto out_unlock;
3225 if (err == 1)
3226 /* The index node was found but it was dirty */
3227 err = 0;
3228 else if (err == 2)
3229 /* The index node was found and it was clean */
3230 err = 1;
3231 else
3232 BUG_ON(err != 0);
3233 } else
3234 err = is_leaf_node_in_tnc(c, key, lnum, offs);
3235
3236out_unlock:
3237 mutex_unlock(&c->tnc_mutex);
3238 return err;
3239}
3240
3241/**
3242 * ubifs_dirty_idx_node - dirty an index node.
3243 * @c: UBIFS file-system description object
3244 * @key: index node key
3245 * @level: index node level
3246 * @lnum: index node LEB number
3247 * @offs: index node offset
3248 *
3249 * This function loads and dirties an index node so that it can be garbage
3250 * collected. The @key argument has to be the key of the first child. This
3251 * function relies on the fact that 0:0 is never a valid LEB number and offset
3252 * for a main-area node. Returns %0 on success and a negative error code on
3253 * failure.
3254 */
3255int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level,
3256 int lnum, int offs)
3257{
3258 struct ubifs_znode *znode;
3259 int err = 0;
3260
3261 mutex_lock(&c->tnc_mutex);
3262 znode = lookup_znode(c, key, level, lnum, offs);
3263 if (!znode)
3264 goto out_unlock;
3265 if (IS_ERR(znode)) {
3266 err = PTR_ERR(znode);
3267 goto out_unlock;
3268 }
3269 znode = dirty_cow_bottom_up(c, znode);
3270 if (IS_ERR(znode)) {
3271 err = PTR_ERR(znode);
3272 goto out_unlock;
3273 }
3274
3275out_unlock:
3276 mutex_unlock(&c->tnc_mutex);
3277 return err;
3278}
3279
3280#ifdef CONFIG_UBIFS_FS_DEBUG
3281
3282/**
3283 * dbg_check_inode_size - check if inode size is correct.
3284 * @c: UBIFS file-system description object
3285 * @inum: inode number
3286 * @size: inode size
3287 *
3288 * This function makes sure that the inode size (@size) is correct and it does
3289 * not have any pages beyond @size. Returns zero if the inode is OK, %-EINVAL
3290 * if it has a data page beyond @size, and other negative error code in case of
3291 * other errors.
3292 */
3293int dbg_check_inode_size(struct ubifs_info *c, const struct inode *inode,
3294 loff_t size)
3295{
3296 int err, n;
3297 union ubifs_key from_key, to_key, *key;
3298 struct ubifs_znode *znode;
3299 unsigned int block;
3300
3301 if (!S_ISREG(inode->i_mode))
3302 return 0;
3303 if (!dbg_is_chk_gen(c))
3304 return 0;
3305
3306 block = (size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT;
3307 data_key_init(c, &from_key, inode->i_ino, block);
3308 highest_data_key(c, &to_key, inode->i_ino);
3309
3310 mutex_lock(&c->tnc_mutex);
3311 err = ubifs_lookup_level0(c, &from_key, &znode, &n);
3312 if (err < 0)
3313 goto out_unlock;
3314
3315 if (err) {
3316 err = -EINVAL;
3317 key = &from_key;
3318 goto out_dump;
3319 }
3320
3321 err = tnc_next(c, &znode, &n);
3322 if (err == -ENOENT) {
3323 err = 0;
3324 goto out_unlock;
3325 }
3326 if (err < 0)
3327 goto out_unlock;
3328
3329 ubifs_assert(err == 0);
3330 key = &znode->zbranch[n].key;
3331 if (!key_in_range(c, key, &from_key, &to_key))
3332 goto out_unlock;
3333
3334out_dump:
3335 block = key_block(c, key);
3336 ubifs_err("inode %lu has size %lld, but there are data at offset %lld "
3337 "(data key %s)", (unsigned long)inode->i_ino, size,
3338 ((loff_t)block) << UBIFS_BLOCK_SHIFT, DBGKEY(key));
3339 mutex_unlock(&c->tnc_mutex);
3340 dbg_dump_inode(c, inode);
3341 dbg_dump_stack();
3342 return -EINVAL;
3343
3344out_unlock:
3345 mutex_unlock(&c->tnc_mutex);
3346 return err;
3347}
3348
3349#endif /* CONFIG_UBIFS_FS_DEBUG */
1/*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * Authors: Adrian Hunter
20 * Artem Bityutskiy (Битюцкий Артём)
21 */
22
23/*
24 * This file implements TNC (Tree Node Cache) which caches indexing nodes of
25 * the UBIFS B-tree.
26 *
27 * At the moment the locking rules of the TNC tree are quite simple and
28 * straightforward. We just have a mutex and lock it when we traverse the
29 * tree. If a znode is not in memory, we read it from flash while still having
30 * the mutex locked.
31 */
32
33#include <linux/crc32.h>
34#include <linux/slab.h>
35#include "ubifs.h"
36
37/*
38 * Returned codes of 'matches_name()' and 'fallible_matches_name()' functions.
39 * @NAME_LESS: name corresponding to the first argument is less than second
40 * @NAME_MATCHES: names match
41 * @NAME_GREATER: name corresponding to the second argument is greater than
42 * first
43 * @NOT_ON_MEDIA: node referred by zbranch does not exist on the media
44 *
45 * These constants were introduce to improve readability.
46 */
47enum {
48 NAME_LESS = 0,
49 NAME_MATCHES = 1,
50 NAME_GREATER = 2,
51 NOT_ON_MEDIA = 3,
52};
53
54/**
55 * insert_old_idx - record an index node obsoleted since the last commit start.
56 * @c: UBIFS file-system description object
57 * @lnum: LEB number of obsoleted index node
58 * @offs: offset of obsoleted index node
59 *
60 * Returns %0 on success, and a negative error code on failure.
61 *
62 * For recovery, there must always be a complete intact version of the index on
63 * flash at all times. That is called the "old index". It is the index as at the
64 * time of the last successful commit. Many of the index nodes in the old index
65 * may be dirty, but they must not be erased until the next successful commit
66 * (at which point that index becomes the old index).
67 *
68 * That means that the garbage collection and the in-the-gaps method of
69 * committing must be able to determine if an index node is in the old index.
70 * Most of the old index nodes can be found by looking up the TNC using the
71 * 'lookup_znode()' function. However, some of the old index nodes may have
72 * been deleted from the current index or may have been changed so much that
73 * they cannot be easily found. In those cases, an entry is added to an RB-tree.
74 * That is what this function does. The RB-tree is ordered by LEB number and
75 * offset because they uniquely identify the old index node.
76 */
77static int insert_old_idx(struct ubifs_info *c, int lnum, int offs)
78{
79 struct ubifs_old_idx *old_idx, *o;
80 struct rb_node **p, *parent = NULL;
81
82 old_idx = kmalloc(sizeof(struct ubifs_old_idx), GFP_NOFS);
83 if (unlikely(!old_idx))
84 return -ENOMEM;
85 old_idx->lnum = lnum;
86 old_idx->offs = offs;
87
88 p = &c->old_idx.rb_node;
89 while (*p) {
90 parent = *p;
91 o = rb_entry(parent, struct ubifs_old_idx, rb);
92 if (lnum < o->lnum)
93 p = &(*p)->rb_left;
94 else if (lnum > o->lnum)
95 p = &(*p)->rb_right;
96 else if (offs < o->offs)
97 p = &(*p)->rb_left;
98 else if (offs > o->offs)
99 p = &(*p)->rb_right;
100 else {
101 ubifs_err("old idx added twice!");
102 kfree(old_idx);
103 return 0;
104 }
105 }
106 rb_link_node(&old_idx->rb, parent, p);
107 rb_insert_color(&old_idx->rb, &c->old_idx);
108 return 0;
109}
110
111/**
112 * insert_old_idx_znode - record a znode obsoleted since last commit start.
113 * @c: UBIFS file-system description object
114 * @znode: znode of obsoleted index node
115 *
116 * Returns %0 on success, and a negative error code on failure.
117 */
118int insert_old_idx_znode(struct ubifs_info *c, struct ubifs_znode *znode)
119{
120 if (znode->parent) {
121 struct ubifs_zbranch *zbr;
122
123 zbr = &znode->parent->zbranch[znode->iip];
124 if (zbr->len)
125 return insert_old_idx(c, zbr->lnum, zbr->offs);
126 } else
127 if (c->zroot.len)
128 return insert_old_idx(c, c->zroot.lnum,
129 c->zroot.offs);
130 return 0;
131}
132
133/**
134 * ins_clr_old_idx_znode - record a znode obsoleted since last commit start.
135 * @c: UBIFS file-system description object
136 * @znode: znode of obsoleted index node
137 *
138 * Returns %0 on success, and a negative error code on failure.
139 */
140static int ins_clr_old_idx_znode(struct ubifs_info *c,
141 struct ubifs_znode *znode)
142{
143 int err;
144
145 if (znode->parent) {
146 struct ubifs_zbranch *zbr;
147
148 zbr = &znode->parent->zbranch[znode->iip];
149 if (zbr->len) {
150 err = insert_old_idx(c, zbr->lnum, zbr->offs);
151 if (err)
152 return err;
153 zbr->lnum = 0;
154 zbr->offs = 0;
155 zbr->len = 0;
156 }
157 } else
158 if (c->zroot.len) {
159 err = insert_old_idx(c, c->zroot.lnum, c->zroot.offs);
160 if (err)
161 return err;
162 c->zroot.lnum = 0;
163 c->zroot.offs = 0;
164 c->zroot.len = 0;
165 }
166 return 0;
167}
168
169/**
170 * destroy_old_idx - destroy the old_idx RB-tree.
171 * @c: UBIFS file-system description object
172 *
173 * During start commit, the old_idx RB-tree is used to avoid overwriting index
174 * nodes that were in the index last commit but have since been deleted. This
175 * is necessary for recovery i.e. the old index must be kept intact until the
176 * new index is successfully written. The old-idx RB-tree is used for the
177 * in-the-gaps method of writing index nodes and is destroyed every commit.
178 */
179void destroy_old_idx(struct ubifs_info *c)
180{
181 struct rb_node *this = c->old_idx.rb_node;
182 struct ubifs_old_idx *old_idx;
183
184 while (this) {
185 if (this->rb_left) {
186 this = this->rb_left;
187 continue;
188 } else if (this->rb_right) {
189 this = this->rb_right;
190 continue;
191 }
192 old_idx = rb_entry(this, struct ubifs_old_idx, rb);
193 this = rb_parent(this);
194 if (this) {
195 if (this->rb_left == &old_idx->rb)
196 this->rb_left = NULL;
197 else
198 this->rb_right = NULL;
199 }
200 kfree(old_idx);
201 }
202 c->old_idx = RB_ROOT;
203}
204
205/**
206 * copy_znode - copy a dirty znode.
207 * @c: UBIFS file-system description object
208 * @znode: znode to copy
209 *
210 * A dirty znode being committed may not be changed, so it is copied.
211 */
212static struct ubifs_znode *copy_znode(struct ubifs_info *c,
213 struct ubifs_znode *znode)
214{
215 struct ubifs_znode *zn;
216
217 zn = kmalloc(c->max_znode_sz, GFP_NOFS);
218 if (unlikely(!zn))
219 return ERR_PTR(-ENOMEM);
220
221 memcpy(zn, znode, c->max_znode_sz);
222 zn->cnext = NULL;
223 __set_bit(DIRTY_ZNODE, &zn->flags);
224 __clear_bit(COW_ZNODE, &zn->flags);
225
226 ubifs_assert(!ubifs_zn_obsolete(znode));
227 __set_bit(OBSOLETE_ZNODE, &znode->flags);
228
229 if (znode->level != 0) {
230 int i;
231 const int n = zn->child_cnt;
232
233 /* The children now have new parent */
234 for (i = 0; i < n; i++) {
235 struct ubifs_zbranch *zbr = &zn->zbranch[i];
236
237 if (zbr->znode)
238 zbr->znode->parent = zn;
239 }
240 }
241
242 atomic_long_inc(&c->dirty_zn_cnt);
243 return zn;
244}
245
246/**
247 * add_idx_dirt - add dirt due to a dirty znode.
248 * @c: UBIFS file-system description object
249 * @lnum: LEB number of index node
250 * @dirt: size of index node
251 *
252 * This function updates lprops dirty space and the new size of the index.
253 */
254static int add_idx_dirt(struct ubifs_info *c, int lnum, int dirt)
255{
256 c->calc_idx_sz -= ALIGN(dirt, 8);
257 return ubifs_add_dirt(c, lnum, dirt);
258}
259
260/**
261 * dirty_cow_znode - ensure a znode is not being committed.
262 * @c: UBIFS file-system description object
263 * @zbr: branch of znode to check
264 *
265 * Returns dirtied znode on success or negative error code on failure.
266 */
267static struct ubifs_znode *dirty_cow_znode(struct ubifs_info *c,
268 struct ubifs_zbranch *zbr)
269{
270 struct ubifs_znode *znode = zbr->znode;
271 struct ubifs_znode *zn;
272 int err;
273
274 if (!ubifs_zn_cow(znode)) {
275 /* znode is not being committed */
276 if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) {
277 atomic_long_inc(&c->dirty_zn_cnt);
278 atomic_long_dec(&c->clean_zn_cnt);
279 atomic_long_dec(&ubifs_clean_zn_cnt);
280 err = add_idx_dirt(c, zbr->lnum, zbr->len);
281 if (unlikely(err))
282 return ERR_PTR(err);
283 }
284 return znode;
285 }
286
287 zn = copy_znode(c, znode);
288 if (IS_ERR(zn))
289 return zn;
290
291 if (zbr->len) {
292 err = insert_old_idx(c, zbr->lnum, zbr->offs);
293 if (unlikely(err))
294 return ERR_PTR(err);
295 err = add_idx_dirt(c, zbr->lnum, zbr->len);
296 } else
297 err = 0;
298
299 zbr->znode = zn;
300 zbr->lnum = 0;
301 zbr->offs = 0;
302 zbr->len = 0;
303
304 if (unlikely(err))
305 return ERR_PTR(err);
306 return zn;
307}
308
309/**
310 * lnc_add - add a leaf node to the leaf node cache.
311 * @c: UBIFS file-system description object
312 * @zbr: zbranch of leaf node
313 * @node: leaf node
314 *
315 * Leaf nodes are non-index nodes directory entry nodes or data nodes. The
316 * purpose of the leaf node cache is to save re-reading the same leaf node over
317 * and over again. Most things are cached by VFS, however the file system must
318 * cache directory entries for readdir and for resolving hash collisions. The
319 * present implementation of the leaf node cache is extremely simple, and
320 * allows for error returns that are not used but that may be needed if a more
321 * complex implementation is created.
322 *
323 * Note, this function does not add the @node object to LNC directly, but
324 * allocates a copy of the object and adds the copy to LNC. The reason for this
325 * is that @node has been allocated outside of the TNC subsystem and will be
326 * used with @c->tnc_mutex unlock upon return from the TNC subsystem. But LNC
327 * may be changed at any time, e.g. freed by the shrinker.
328 */
329static int lnc_add(struct ubifs_info *c, struct ubifs_zbranch *zbr,
330 const void *node)
331{
332 int err;
333 void *lnc_node;
334 const struct ubifs_dent_node *dent = node;
335
336 ubifs_assert(!zbr->leaf);
337 ubifs_assert(zbr->len != 0);
338 ubifs_assert(is_hash_key(c, &zbr->key));
339
340 err = ubifs_validate_entry(c, dent);
341 if (err) {
342 dump_stack();
343 ubifs_dump_node(c, dent);
344 return err;
345 }
346
347 lnc_node = kmemdup(node, zbr->len, GFP_NOFS);
348 if (!lnc_node)
349 /* We don't have to have the cache, so no error */
350 return 0;
351
352 zbr->leaf = lnc_node;
353 return 0;
354}
355
356 /**
357 * lnc_add_directly - add a leaf node to the leaf-node-cache.
358 * @c: UBIFS file-system description object
359 * @zbr: zbranch of leaf node
360 * @node: leaf node
361 *
362 * This function is similar to 'lnc_add()', but it does not create a copy of
363 * @node but inserts @node to TNC directly.
364 */
365static int lnc_add_directly(struct ubifs_info *c, struct ubifs_zbranch *zbr,
366 void *node)
367{
368 int err;
369
370 ubifs_assert(!zbr->leaf);
371 ubifs_assert(zbr->len != 0);
372
373 err = ubifs_validate_entry(c, node);
374 if (err) {
375 dump_stack();
376 ubifs_dump_node(c, node);
377 return err;
378 }
379
380 zbr->leaf = node;
381 return 0;
382}
383
384/**
385 * lnc_free - remove a leaf node from the leaf node cache.
386 * @zbr: zbranch of leaf node
387 * @node: leaf node
388 */
389static void lnc_free(struct ubifs_zbranch *zbr)
390{
391 if (!zbr->leaf)
392 return;
393 kfree(zbr->leaf);
394 zbr->leaf = NULL;
395}
396
397/**
398 * tnc_read_node_nm - read a "hashed" leaf node.
399 * @c: UBIFS file-system description object
400 * @zbr: key and position of the node
401 * @node: node is returned here
402 *
403 * This function reads a "hashed" node defined by @zbr from the leaf node cache
404 * (in it is there) or from the hash media, in which case the node is also
405 * added to LNC. Returns zero in case of success or a negative negative error
406 * code in case of failure.
407 */
408static int tnc_read_node_nm(struct ubifs_info *c, struct ubifs_zbranch *zbr,
409 void *node)
410{
411 int err;
412
413 ubifs_assert(is_hash_key(c, &zbr->key));
414
415 if (zbr->leaf) {
416 /* Read from the leaf node cache */
417 ubifs_assert(zbr->len != 0);
418 memcpy(node, zbr->leaf, zbr->len);
419 return 0;
420 }
421
422 err = ubifs_tnc_read_node(c, zbr, node);
423 if (err)
424 return err;
425
426 /* Add the node to the leaf node cache */
427 err = lnc_add(c, zbr, node);
428 return err;
429}
430
431/**
432 * try_read_node - read a node if it is a node.
433 * @c: UBIFS file-system description object
434 * @buf: buffer to read to
435 * @type: node type
436 * @len: node length (not aligned)
437 * @lnum: LEB number of node to read
438 * @offs: offset of node to read
439 *
440 * This function tries to read a node of known type and length, checks it and
441 * stores it in @buf. This function returns %1 if a node is present and %0 if
442 * a node is not present. A negative error code is returned for I/O errors.
443 * This function performs that same function as ubifs_read_node except that
444 * it does not require that there is actually a node present and instead
445 * the return code indicates if a node was read.
446 *
447 * Note, this function does not check CRC of data nodes if @c->no_chk_data_crc
448 * is true (it is controlled by corresponding mount option). However, if
449 * @c->mounting or @c->remounting_rw is true (we are mounting or re-mounting to
450 * R/W mode), @c->no_chk_data_crc is ignored and CRC is checked. This is
451 * because during mounting or re-mounting from R/O mode to R/W mode we may read
452 * journal nodes (when replying the journal or doing the recovery) and the
453 * journal nodes may potentially be corrupted, so checking is required.
454 */
455static int try_read_node(const struct ubifs_info *c, void *buf, int type,
456 int len, int lnum, int offs)
457{
458 int err, node_len;
459 struct ubifs_ch *ch = buf;
460 uint32_t crc, node_crc;
461
462 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
463
464 err = ubifs_leb_read(c, lnum, buf, offs, len, 1);
465 if (err) {
466 ubifs_err("cannot read node type %d from LEB %d:%d, error %d",
467 type, lnum, offs, err);
468 return err;
469 }
470
471 if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC)
472 return 0;
473
474 if (ch->node_type != type)
475 return 0;
476
477 node_len = le32_to_cpu(ch->len);
478 if (node_len != len)
479 return 0;
480
481 if (type == UBIFS_DATA_NODE && c->no_chk_data_crc && !c->mounting &&
482 !c->remounting_rw)
483 return 1;
484
485 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
486 node_crc = le32_to_cpu(ch->crc);
487 if (crc != node_crc)
488 return 0;
489
490 return 1;
491}
492
493/**
494 * fallible_read_node - try to read a leaf node.
495 * @c: UBIFS file-system description object
496 * @key: key of node to read
497 * @zbr: position of node
498 * @node: node returned
499 *
500 * This function tries to read a node and returns %1 if the node is read, %0
501 * if the node is not present, and a negative error code in the case of error.
502 */
503static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
504 struct ubifs_zbranch *zbr, void *node)
505{
506 int ret;
507
508 dbg_tnck(key, "LEB %d:%d, key ", zbr->lnum, zbr->offs);
509
510 ret = try_read_node(c, node, key_type(c, key), zbr->len, zbr->lnum,
511 zbr->offs);
512 if (ret == 1) {
513 union ubifs_key node_key;
514 struct ubifs_dent_node *dent = node;
515
516 /* All nodes have key in the same place */
517 key_read(c, &dent->key, &node_key);
518 if (keys_cmp(c, key, &node_key) != 0)
519 ret = 0;
520 }
521 if (ret == 0 && c->replaying)
522 dbg_mntk(key, "dangling branch LEB %d:%d len %d, key ",
523 zbr->lnum, zbr->offs, zbr->len);
524 return ret;
525}
526
527/**
528 * matches_name - determine if a direntry or xattr entry matches a given name.
529 * @c: UBIFS file-system description object
530 * @zbr: zbranch of dent
531 * @nm: name to match
532 *
533 * This function checks if xentry/direntry referred by zbranch @zbr matches name
534 * @nm. Returns %NAME_MATCHES if it does, %NAME_LESS if the name referred by
535 * @zbr is less than @nm, and %NAME_GREATER if it is greater than @nm. In case
536 * of failure, a negative error code is returned.
537 */
538static int matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr,
539 const struct qstr *nm)
540{
541 struct ubifs_dent_node *dent;
542 int nlen, err;
543
544 /* If possible, match against the dent in the leaf node cache */
545 if (!zbr->leaf) {
546 dent = kmalloc(zbr->len, GFP_NOFS);
547 if (!dent)
548 return -ENOMEM;
549
550 err = ubifs_tnc_read_node(c, zbr, dent);
551 if (err)
552 goto out_free;
553
554 /* Add the node to the leaf node cache */
555 err = lnc_add_directly(c, zbr, dent);
556 if (err)
557 goto out_free;
558 } else
559 dent = zbr->leaf;
560
561 nlen = le16_to_cpu(dent->nlen);
562 err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
563 if (err == 0) {
564 if (nlen == nm->len)
565 return NAME_MATCHES;
566 else if (nlen < nm->len)
567 return NAME_LESS;
568 else
569 return NAME_GREATER;
570 } else if (err < 0)
571 return NAME_LESS;
572 else
573 return NAME_GREATER;
574
575out_free:
576 kfree(dent);
577 return err;
578}
579
580/**
581 * get_znode - get a TNC znode that may not be loaded yet.
582 * @c: UBIFS file-system description object
583 * @znode: parent znode
584 * @n: znode branch slot number
585 *
586 * This function returns the znode or a negative error code.
587 */
588static struct ubifs_znode *get_znode(struct ubifs_info *c,
589 struct ubifs_znode *znode, int n)
590{
591 struct ubifs_zbranch *zbr;
592
593 zbr = &znode->zbranch[n];
594 if (zbr->znode)
595 znode = zbr->znode;
596 else
597 znode = ubifs_load_znode(c, zbr, znode, n);
598 return znode;
599}
600
601/**
602 * tnc_next - find next TNC entry.
603 * @c: UBIFS file-system description object
604 * @zn: znode is passed and returned here
605 * @n: znode branch slot number is passed and returned here
606 *
607 * This function returns %0 if the next TNC entry is found, %-ENOENT if there is
608 * no next entry, or a negative error code otherwise.
609 */
610static int tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
611{
612 struct ubifs_znode *znode = *zn;
613 int nn = *n;
614
615 nn += 1;
616 if (nn < znode->child_cnt) {
617 *n = nn;
618 return 0;
619 }
620 while (1) {
621 struct ubifs_znode *zp;
622
623 zp = znode->parent;
624 if (!zp)
625 return -ENOENT;
626 nn = znode->iip + 1;
627 znode = zp;
628 if (nn < znode->child_cnt) {
629 znode = get_znode(c, znode, nn);
630 if (IS_ERR(znode))
631 return PTR_ERR(znode);
632 while (znode->level != 0) {
633 znode = get_znode(c, znode, 0);
634 if (IS_ERR(znode))
635 return PTR_ERR(znode);
636 }
637 nn = 0;
638 break;
639 }
640 }
641 *zn = znode;
642 *n = nn;
643 return 0;
644}
645
646/**
647 * tnc_prev - find previous TNC entry.
648 * @c: UBIFS file-system description object
649 * @zn: znode is returned here
650 * @n: znode branch slot number is passed and returned here
651 *
652 * This function returns %0 if the previous TNC entry is found, %-ENOENT if
653 * there is no next entry, or a negative error code otherwise.
654 */
655static int tnc_prev(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
656{
657 struct ubifs_znode *znode = *zn;
658 int nn = *n;
659
660 if (nn > 0) {
661 *n = nn - 1;
662 return 0;
663 }
664 while (1) {
665 struct ubifs_znode *zp;
666
667 zp = znode->parent;
668 if (!zp)
669 return -ENOENT;
670 nn = znode->iip - 1;
671 znode = zp;
672 if (nn >= 0) {
673 znode = get_znode(c, znode, nn);
674 if (IS_ERR(znode))
675 return PTR_ERR(znode);
676 while (znode->level != 0) {
677 nn = znode->child_cnt - 1;
678 znode = get_znode(c, znode, nn);
679 if (IS_ERR(znode))
680 return PTR_ERR(znode);
681 }
682 nn = znode->child_cnt - 1;
683 break;
684 }
685 }
686 *zn = znode;
687 *n = nn;
688 return 0;
689}
690
691/**
692 * resolve_collision - resolve a collision.
693 * @c: UBIFS file-system description object
694 * @key: key of a directory or extended attribute entry
695 * @zn: znode is returned here
696 * @n: zbranch number is passed and returned here
697 * @nm: name of the entry
698 *
699 * This function is called for "hashed" keys to make sure that the found key
700 * really corresponds to the looked up node (directory or extended attribute
701 * entry). It returns %1 and sets @zn and @n if the collision is resolved.
702 * %0 is returned if @nm is not found and @zn and @n are set to the previous
703 * entry, i.e. to the entry after which @nm could follow if it were in TNC.
704 * This means that @n may be set to %-1 if the leftmost key in @zn is the
705 * previous one. A negative error code is returned on failures.
706 */
707static int resolve_collision(struct ubifs_info *c, const union ubifs_key *key,
708 struct ubifs_znode **zn, int *n,
709 const struct qstr *nm)
710{
711 int err;
712
713 err = matches_name(c, &(*zn)->zbranch[*n], nm);
714 if (unlikely(err < 0))
715 return err;
716 if (err == NAME_MATCHES)
717 return 1;
718
719 if (err == NAME_GREATER) {
720 /* Look left */
721 while (1) {
722 err = tnc_prev(c, zn, n);
723 if (err == -ENOENT) {
724 ubifs_assert(*n == 0);
725 *n = -1;
726 return 0;
727 }
728 if (err < 0)
729 return err;
730 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
731 /*
732 * We have found the branch after which we would
733 * like to insert, but inserting in this znode
734 * may still be wrong. Consider the following 3
735 * znodes, in the case where we are resolving a
736 * collision with Key2.
737 *
738 * znode zp
739 * ----------------------
740 * level 1 | Key0 | Key1 |
741 * -----------------------
742 * | |
743 * znode za | | znode zb
744 * ------------ ------------
745 * level 0 | Key0 | | Key2 |
746 * ------------ ------------
747 *
748 * The lookup finds Key2 in znode zb. Lets say
749 * there is no match and the name is greater so
750 * we look left. When we find Key0, we end up
751 * here. If we return now, we will insert into
752 * znode za at slot n = 1. But that is invalid
753 * according to the parent's keys. Key2 must
754 * be inserted into znode zb.
755 *
756 * Note, this problem is not relevant for the
757 * case when we go right, because
758 * 'tnc_insert()' would correct the parent key.
759 */
760 if (*n == (*zn)->child_cnt - 1) {
761 err = tnc_next(c, zn, n);
762 if (err) {
763 /* Should be impossible */
764 ubifs_assert(0);
765 if (err == -ENOENT)
766 err = -EINVAL;
767 return err;
768 }
769 ubifs_assert(*n == 0);
770 *n = -1;
771 }
772 return 0;
773 }
774 err = matches_name(c, &(*zn)->zbranch[*n], nm);
775 if (err < 0)
776 return err;
777 if (err == NAME_LESS)
778 return 0;
779 if (err == NAME_MATCHES)
780 return 1;
781 ubifs_assert(err == NAME_GREATER);
782 }
783 } else {
784 int nn = *n;
785 struct ubifs_znode *znode = *zn;
786
787 /* Look right */
788 while (1) {
789 err = tnc_next(c, &znode, &nn);
790 if (err == -ENOENT)
791 return 0;
792 if (err < 0)
793 return err;
794 if (keys_cmp(c, &znode->zbranch[nn].key, key))
795 return 0;
796 err = matches_name(c, &znode->zbranch[nn], nm);
797 if (err < 0)
798 return err;
799 if (err == NAME_GREATER)
800 return 0;
801 *zn = znode;
802 *n = nn;
803 if (err == NAME_MATCHES)
804 return 1;
805 ubifs_assert(err == NAME_LESS);
806 }
807 }
808}
809
810/**
811 * fallible_matches_name - determine if a dent matches a given name.
812 * @c: UBIFS file-system description object
813 * @zbr: zbranch of dent
814 * @nm: name to match
815 *
816 * This is a "fallible" version of 'matches_name()' function which does not
817 * panic if the direntry/xentry referred by @zbr does not exist on the media.
818 *
819 * This function checks if xentry/direntry referred by zbranch @zbr matches name
820 * @nm. Returns %NAME_MATCHES it does, %NAME_LESS if the name referred by @zbr
821 * is less than @nm, %NAME_GREATER if it is greater than @nm, and @NOT_ON_MEDIA
822 * if xentry/direntry referred by @zbr does not exist on the media. A negative
823 * error code is returned in case of failure.
824 */
825static int fallible_matches_name(struct ubifs_info *c,
826 struct ubifs_zbranch *zbr,
827 const struct qstr *nm)
828{
829 struct ubifs_dent_node *dent;
830 int nlen, err;
831
832 /* If possible, match against the dent in the leaf node cache */
833 if (!zbr->leaf) {
834 dent = kmalloc(zbr->len, GFP_NOFS);
835 if (!dent)
836 return -ENOMEM;
837
838 err = fallible_read_node(c, &zbr->key, zbr, dent);
839 if (err < 0)
840 goto out_free;
841 if (err == 0) {
842 /* The node was not present */
843 err = NOT_ON_MEDIA;
844 goto out_free;
845 }
846 ubifs_assert(err == 1);
847
848 err = lnc_add_directly(c, zbr, dent);
849 if (err)
850 goto out_free;
851 } else
852 dent = zbr->leaf;
853
854 nlen = le16_to_cpu(dent->nlen);
855 err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
856 if (err == 0) {
857 if (nlen == nm->len)
858 return NAME_MATCHES;
859 else if (nlen < nm->len)
860 return NAME_LESS;
861 else
862 return NAME_GREATER;
863 } else if (err < 0)
864 return NAME_LESS;
865 else
866 return NAME_GREATER;
867
868out_free:
869 kfree(dent);
870 return err;
871}
872
873/**
874 * fallible_resolve_collision - resolve a collision even if nodes are missing.
875 * @c: UBIFS file-system description object
876 * @key: key
877 * @zn: znode is returned here
878 * @n: branch number is passed and returned here
879 * @nm: name of directory entry
880 * @adding: indicates caller is adding a key to the TNC
881 *
882 * This is a "fallible" version of the 'resolve_collision()' function which
883 * does not panic if one of the nodes referred to by TNC does not exist on the
884 * media. This may happen when replaying the journal if a deleted node was
885 * Garbage-collected and the commit was not done. A branch that refers to a node
886 * that is not present is called a dangling branch. The following are the return
887 * codes for this function:
888 * o if @nm was found, %1 is returned and @zn and @n are set to the found
889 * branch;
890 * o if we are @adding and @nm was not found, %0 is returned;
891 * o if we are not @adding and @nm was not found, but a dangling branch was
892 * found, then %1 is returned and @zn and @n are set to the dangling branch;
893 * o a negative error code is returned in case of failure.
894 */
895static int fallible_resolve_collision(struct ubifs_info *c,
896 const union ubifs_key *key,
897 struct ubifs_znode **zn, int *n,
898 const struct qstr *nm, int adding)
899{
900 struct ubifs_znode *o_znode = NULL, *znode = *zn;
901 int uninitialized_var(o_n), err, cmp, unsure = 0, nn = *n;
902
903 cmp = fallible_matches_name(c, &znode->zbranch[nn], nm);
904 if (unlikely(cmp < 0))
905 return cmp;
906 if (cmp == NAME_MATCHES)
907 return 1;
908 if (cmp == NOT_ON_MEDIA) {
909 o_znode = znode;
910 o_n = nn;
911 /*
912 * We are unlucky and hit a dangling branch straight away.
913 * Now we do not really know where to go to find the needed
914 * branch - to the left or to the right. Well, let's try left.
915 */
916 unsure = 1;
917 } else if (!adding)
918 unsure = 1; /* Remove a dangling branch wherever it is */
919
920 if (cmp == NAME_GREATER || unsure) {
921 /* Look left */
922 while (1) {
923 err = tnc_prev(c, zn, n);
924 if (err == -ENOENT) {
925 ubifs_assert(*n == 0);
926 *n = -1;
927 break;
928 }
929 if (err < 0)
930 return err;
931 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
932 /* See comments in 'resolve_collision()' */
933 if (*n == (*zn)->child_cnt - 1) {
934 err = tnc_next(c, zn, n);
935 if (err) {
936 /* Should be impossible */
937 ubifs_assert(0);
938 if (err == -ENOENT)
939 err = -EINVAL;
940 return err;
941 }
942 ubifs_assert(*n == 0);
943 *n = -1;
944 }
945 break;
946 }
947 err = fallible_matches_name(c, &(*zn)->zbranch[*n], nm);
948 if (err < 0)
949 return err;
950 if (err == NAME_MATCHES)
951 return 1;
952 if (err == NOT_ON_MEDIA) {
953 o_znode = *zn;
954 o_n = *n;
955 continue;
956 }
957 if (!adding)
958 continue;
959 if (err == NAME_LESS)
960 break;
961 else
962 unsure = 0;
963 }
964 }
965
966 if (cmp == NAME_LESS || unsure) {
967 /* Look right */
968 *zn = znode;
969 *n = nn;
970 while (1) {
971 err = tnc_next(c, &znode, &nn);
972 if (err == -ENOENT)
973 break;
974 if (err < 0)
975 return err;
976 if (keys_cmp(c, &znode->zbranch[nn].key, key))
977 break;
978 err = fallible_matches_name(c, &znode->zbranch[nn], nm);
979 if (err < 0)
980 return err;
981 if (err == NAME_GREATER)
982 break;
983 *zn = znode;
984 *n = nn;
985 if (err == NAME_MATCHES)
986 return 1;
987 if (err == NOT_ON_MEDIA) {
988 o_znode = znode;
989 o_n = nn;
990 }
991 }
992 }
993
994 /* Never match a dangling branch when adding */
995 if (adding || !o_znode)
996 return 0;
997
998 dbg_mntk(key, "dangling match LEB %d:%d len %d key ",
999 o_znode->zbranch[o_n].lnum, o_znode->zbranch[o_n].offs,
1000 o_znode->zbranch[o_n].len);
1001 *zn = o_znode;
1002 *n = o_n;
1003 return 1;
1004}
1005
1006/**
1007 * matches_position - determine if a zbranch matches a given position.
1008 * @zbr: zbranch of dent
1009 * @lnum: LEB number of dent to match
1010 * @offs: offset of dent to match
1011 *
1012 * This function returns %1 if @lnum:@offs matches, and %0 otherwise.
1013 */
1014static int matches_position(struct ubifs_zbranch *zbr, int lnum, int offs)
1015{
1016 if (zbr->lnum == lnum && zbr->offs == offs)
1017 return 1;
1018 else
1019 return 0;
1020}
1021
1022/**
1023 * resolve_collision_directly - resolve a collision directly.
1024 * @c: UBIFS file-system description object
1025 * @key: key of directory entry
1026 * @zn: znode is passed and returned here
1027 * @n: zbranch number is passed and returned here
1028 * @lnum: LEB number of dent node to match
1029 * @offs: offset of dent node to match
1030 *
1031 * This function is used for "hashed" keys to make sure the found directory or
1032 * extended attribute entry node is what was looked for. It is used when the
1033 * flash address of the right node is known (@lnum:@offs) which makes it much
1034 * easier to resolve collisions (no need to read entries and match full
1035 * names). This function returns %1 and sets @zn and @n if the collision is
1036 * resolved, %0 if @lnum:@offs is not found and @zn and @n are set to the
1037 * previous directory entry. Otherwise a negative error code is returned.
1038 */
1039static int resolve_collision_directly(struct ubifs_info *c,
1040 const union ubifs_key *key,
1041 struct ubifs_znode **zn, int *n,
1042 int lnum, int offs)
1043{
1044 struct ubifs_znode *znode;
1045 int nn, err;
1046
1047 znode = *zn;
1048 nn = *n;
1049 if (matches_position(&znode->zbranch[nn], lnum, offs))
1050 return 1;
1051
1052 /* Look left */
1053 while (1) {
1054 err = tnc_prev(c, &znode, &nn);
1055 if (err == -ENOENT)
1056 break;
1057 if (err < 0)
1058 return err;
1059 if (keys_cmp(c, &znode->zbranch[nn].key, key))
1060 break;
1061 if (matches_position(&znode->zbranch[nn], lnum, offs)) {
1062 *zn = znode;
1063 *n = nn;
1064 return 1;
1065 }
1066 }
1067
1068 /* Look right */
1069 znode = *zn;
1070 nn = *n;
1071 while (1) {
1072 err = tnc_next(c, &znode, &nn);
1073 if (err == -ENOENT)
1074 return 0;
1075 if (err < 0)
1076 return err;
1077 if (keys_cmp(c, &znode->zbranch[nn].key, key))
1078 return 0;
1079 *zn = znode;
1080 *n = nn;
1081 if (matches_position(&znode->zbranch[nn], lnum, offs))
1082 return 1;
1083 }
1084}
1085
1086/**
1087 * dirty_cow_bottom_up - dirty a znode and its ancestors.
1088 * @c: UBIFS file-system description object
1089 * @znode: znode to dirty
1090 *
1091 * If we do not have a unique key that resides in a znode, then we cannot
1092 * dirty that znode from the top down (i.e. by using lookup_level0_dirty)
1093 * This function records the path back to the last dirty ancestor, and then
1094 * dirties the znodes on that path.
1095 */
1096static struct ubifs_znode *dirty_cow_bottom_up(struct ubifs_info *c,
1097 struct ubifs_znode *znode)
1098{
1099 struct ubifs_znode *zp;
1100 int *path = c->bottom_up_buf, p = 0;
1101
1102 ubifs_assert(c->zroot.znode);
1103 ubifs_assert(znode);
1104 if (c->zroot.znode->level > BOTTOM_UP_HEIGHT) {
1105 kfree(c->bottom_up_buf);
1106 c->bottom_up_buf = kmalloc(c->zroot.znode->level * sizeof(int),
1107 GFP_NOFS);
1108 if (!c->bottom_up_buf)
1109 return ERR_PTR(-ENOMEM);
1110 path = c->bottom_up_buf;
1111 }
1112 if (c->zroot.znode->level) {
1113 /* Go up until parent is dirty */
1114 while (1) {
1115 int n;
1116
1117 zp = znode->parent;
1118 if (!zp)
1119 break;
1120 n = znode->iip;
1121 ubifs_assert(p < c->zroot.znode->level);
1122 path[p++] = n;
1123 if (!zp->cnext && ubifs_zn_dirty(znode))
1124 break;
1125 znode = zp;
1126 }
1127 }
1128
1129 /* Come back down, dirtying as we go */
1130 while (1) {
1131 struct ubifs_zbranch *zbr;
1132
1133 zp = znode->parent;
1134 if (zp) {
1135 ubifs_assert(path[p - 1] >= 0);
1136 ubifs_assert(path[p - 1] < zp->child_cnt);
1137 zbr = &zp->zbranch[path[--p]];
1138 znode = dirty_cow_znode(c, zbr);
1139 } else {
1140 ubifs_assert(znode == c->zroot.znode);
1141 znode = dirty_cow_znode(c, &c->zroot);
1142 }
1143 if (IS_ERR(znode) || !p)
1144 break;
1145 ubifs_assert(path[p - 1] >= 0);
1146 ubifs_assert(path[p - 1] < znode->child_cnt);
1147 znode = znode->zbranch[path[p - 1]].znode;
1148 }
1149
1150 return znode;
1151}
1152
1153/**
1154 * ubifs_lookup_level0 - search for zero-level znode.
1155 * @c: UBIFS file-system description object
1156 * @key: key to lookup
1157 * @zn: znode is returned here
1158 * @n: znode branch slot number is returned here
1159 *
1160 * This function looks up the TNC tree and search for zero-level znode which
1161 * refers key @key. The found zero-level znode is returned in @zn. There are 3
1162 * cases:
1163 * o exact match, i.e. the found zero-level znode contains key @key, then %1
1164 * is returned and slot number of the matched branch is stored in @n;
1165 * o not exact match, which means that zero-level znode does not contain
1166 * @key, then %0 is returned and slot number of the closest branch is stored
1167 * in @n;
1168 * o @key is so small that it is even less than the lowest key of the
1169 * leftmost zero-level node, then %0 is returned and %0 is stored in @n.
1170 *
1171 * Note, when the TNC tree is traversed, some znodes may be absent, then this
1172 * function reads corresponding indexing nodes and inserts them to TNC. In
1173 * case of failure, a negative error code is returned.
1174 */
1175int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
1176 struct ubifs_znode **zn, int *n)
1177{
1178 int err, exact;
1179 struct ubifs_znode *znode;
1180 unsigned long time = get_seconds();
1181
1182 dbg_tnck(key, "search key ");
1183 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
1184
1185 znode = c->zroot.znode;
1186 if (unlikely(!znode)) {
1187 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
1188 if (IS_ERR(znode))
1189 return PTR_ERR(znode);
1190 }
1191
1192 znode->time = time;
1193
1194 while (1) {
1195 struct ubifs_zbranch *zbr;
1196
1197 exact = ubifs_search_zbranch(c, znode, key, n);
1198
1199 if (znode->level == 0)
1200 break;
1201
1202 if (*n < 0)
1203 *n = 0;
1204 zbr = &znode->zbranch[*n];
1205
1206 if (zbr->znode) {
1207 znode->time = time;
1208 znode = zbr->znode;
1209 continue;
1210 }
1211
1212 /* znode is not in TNC cache, load it from the media */
1213 znode = ubifs_load_znode(c, zbr, znode, *n);
1214 if (IS_ERR(znode))
1215 return PTR_ERR(znode);
1216 }
1217
1218 *zn = znode;
1219 if (exact || !is_hash_key(c, key) || *n != -1) {
1220 dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
1221 return exact;
1222 }
1223
1224 /*
1225 * Here is a tricky place. We have not found the key and this is a
1226 * "hashed" key, which may collide. The rest of the code deals with
1227 * situations like this:
1228 *
1229 * | 3 | 5 |
1230 * / \
1231 * | 3 | 5 | | 6 | 7 | (x)
1232 *
1233 * Or more a complex example:
1234 *
1235 * | 1 | 5 |
1236 * / \
1237 * | 1 | 3 | | 5 | 8 |
1238 * \ /
1239 * | 5 | 5 | | 6 | 7 | (x)
1240 *
1241 * In the examples, if we are looking for key "5", we may reach nodes
1242 * marked with "(x)". In this case what we have do is to look at the
1243 * left and see if there is "5" key there. If there is, we have to
1244 * return it.
1245 *
1246 * Note, this whole situation is possible because we allow to have
1247 * elements which are equivalent to the next key in the parent in the
1248 * children of current znode. For example, this happens if we split a
1249 * znode like this: | 3 | 5 | 5 | 6 | 7 |, which results in something
1250 * like this:
1251 * | 3 | 5 |
1252 * / \
1253 * | 3 | 5 | | 5 | 6 | 7 |
1254 * ^
1255 * And this becomes what is at the first "picture" after key "5" marked
1256 * with "^" is removed. What could be done is we could prohibit
1257 * splitting in the middle of the colliding sequence. Also, when
1258 * removing the leftmost key, we would have to correct the key of the
1259 * parent node, which would introduce additional complications. Namely,
1260 * if we changed the leftmost key of the parent znode, the garbage
1261 * collector would be unable to find it (GC is doing this when GC'ing
1262 * indexing LEBs). Although we already have an additional RB-tree where
1263 * we save such changed znodes (see 'ins_clr_old_idx_znode()') until
1264 * after the commit. But anyway, this does not look easy to implement
1265 * so we did not try this.
1266 */
1267 err = tnc_prev(c, &znode, n);
1268 if (err == -ENOENT) {
1269 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1270 *n = -1;
1271 return 0;
1272 }
1273 if (unlikely(err < 0))
1274 return err;
1275 if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
1276 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1277 *n = -1;
1278 return 0;
1279 }
1280
1281 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1282 *zn = znode;
1283 return 1;
1284}
1285
1286/**
1287 * lookup_level0_dirty - search for zero-level znode dirtying.
1288 * @c: UBIFS file-system description object
1289 * @key: key to lookup
1290 * @zn: znode is returned here
1291 * @n: znode branch slot number is returned here
1292 *
1293 * This function looks up the TNC tree and search for zero-level znode which
1294 * refers key @key. The found zero-level znode is returned in @zn. There are 3
1295 * cases:
1296 * o exact match, i.e. the found zero-level znode contains key @key, then %1
1297 * is returned and slot number of the matched branch is stored in @n;
1298 * o not exact match, which means that zero-level znode does not contain @key
1299 * then %0 is returned and slot number of the closed branch is stored in
1300 * @n;
1301 * o @key is so small that it is even less than the lowest key of the
1302 * leftmost zero-level node, then %0 is returned and %-1 is stored in @n.
1303 *
1304 * Additionally all znodes in the path from the root to the located zero-level
1305 * znode are marked as dirty.
1306 *
1307 * Note, when the TNC tree is traversed, some znodes may be absent, then this
1308 * function reads corresponding indexing nodes and inserts them to TNC. In
1309 * case of failure, a negative error code is returned.
1310 */
1311static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key,
1312 struct ubifs_znode **zn, int *n)
1313{
1314 int err, exact;
1315 struct ubifs_znode *znode;
1316 unsigned long time = get_seconds();
1317
1318 dbg_tnck(key, "search and dirty key ");
1319
1320 znode = c->zroot.znode;
1321 if (unlikely(!znode)) {
1322 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
1323 if (IS_ERR(znode))
1324 return PTR_ERR(znode);
1325 }
1326
1327 znode = dirty_cow_znode(c, &c->zroot);
1328 if (IS_ERR(znode))
1329 return PTR_ERR(znode);
1330
1331 znode->time = time;
1332
1333 while (1) {
1334 struct ubifs_zbranch *zbr;
1335
1336 exact = ubifs_search_zbranch(c, znode, key, n);
1337
1338 if (znode->level == 0)
1339 break;
1340
1341 if (*n < 0)
1342 *n = 0;
1343 zbr = &znode->zbranch[*n];
1344
1345 if (zbr->znode) {
1346 znode->time = time;
1347 znode = dirty_cow_znode(c, zbr);
1348 if (IS_ERR(znode))
1349 return PTR_ERR(znode);
1350 continue;
1351 }
1352
1353 /* znode is not in TNC cache, load it from the media */
1354 znode = ubifs_load_znode(c, zbr, znode, *n);
1355 if (IS_ERR(znode))
1356 return PTR_ERR(znode);
1357 znode = dirty_cow_znode(c, zbr);
1358 if (IS_ERR(znode))
1359 return PTR_ERR(znode);
1360 }
1361
1362 *zn = znode;
1363 if (exact || !is_hash_key(c, key) || *n != -1) {
1364 dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
1365 return exact;
1366 }
1367
1368 /*
1369 * See huge comment at 'lookup_level0_dirty()' what is the rest of the
1370 * code.
1371 */
1372 err = tnc_prev(c, &znode, n);
1373 if (err == -ENOENT) {
1374 *n = -1;
1375 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1376 return 0;
1377 }
1378 if (unlikely(err < 0))
1379 return err;
1380 if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
1381 *n = -1;
1382 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1383 return 0;
1384 }
1385
1386 if (znode->cnext || !ubifs_zn_dirty(znode)) {
1387 znode = dirty_cow_bottom_up(c, znode);
1388 if (IS_ERR(znode))
1389 return PTR_ERR(znode);
1390 }
1391
1392 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1393 *zn = znode;
1394 return 1;
1395}
1396
1397/**
1398 * maybe_leb_gced - determine if a LEB may have been garbage collected.
1399 * @c: UBIFS file-system description object
1400 * @lnum: LEB number
1401 * @gc_seq1: garbage collection sequence number
1402 *
1403 * This function determines if @lnum may have been garbage collected since
1404 * sequence number @gc_seq1. If it may have been then %1 is returned, otherwise
1405 * %0 is returned.
1406 */
1407static int maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1)
1408{
1409 int gc_seq2, gced_lnum;
1410
1411 gced_lnum = c->gced_lnum;
1412 smp_rmb();
1413 gc_seq2 = c->gc_seq;
1414 /* Same seq means no GC */
1415 if (gc_seq1 == gc_seq2)
1416 return 0;
1417 /* Different by more than 1 means we don't know */
1418 if (gc_seq1 + 1 != gc_seq2)
1419 return 1;
1420 /*
1421 * We have seen the sequence number has increased by 1. Now we need to
1422 * be sure we read the right LEB number, so read it again.
1423 */
1424 smp_rmb();
1425 if (gced_lnum != c->gced_lnum)
1426 return 1;
1427 /* Finally we can check lnum */
1428 if (gced_lnum == lnum)
1429 return 1;
1430 return 0;
1431}
1432
1433/**
1434 * ubifs_tnc_locate - look up a file-system node and return it and its location.
1435 * @c: UBIFS file-system description object
1436 * @key: node key to lookup
1437 * @node: the node is returned here
1438 * @lnum: LEB number is returned here
1439 * @offs: offset is returned here
1440 *
1441 * This function looks up and reads node with key @key. The caller has to make
1442 * sure the @node buffer is large enough to fit the node. Returns zero in case
1443 * of success, %-ENOENT if the node was not found, and a negative error code in
1444 * case of failure. The node location can be returned in @lnum and @offs.
1445 */
1446int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key,
1447 void *node, int *lnum, int *offs)
1448{
1449 int found, n, err, safely = 0, gc_seq1;
1450 struct ubifs_znode *znode;
1451 struct ubifs_zbranch zbr, *zt;
1452
1453again:
1454 mutex_lock(&c->tnc_mutex);
1455 found = ubifs_lookup_level0(c, key, &znode, &n);
1456 if (!found) {
1457 err = -ENOENT;
1458 goto out;
1459 } else if (found < 0) {
1460 err = found;
1461 goto out;
1462 }
1463 zt = &znode->zbranch[n];
1464 if (lnum) {
1465 *lnum = zt->lnum;
1466 *offs = zt->offs;
1467 }
1468 if (is_hash_key(c, key)) {
1469 /*
1470 * In this case the leaf node cache gets used, so we pass the
1471 * address of the zbranch and keep the mutex locked
1472 */
1473 err = tnc_read_node_nm(c, zt, node);
1474 goto out;
1475 }
1476 if (safely) {
1477 err = ubifs_tnc_read_node(c, zt, node);
1478 goto out;
1479 }
1480 /* Drop the TNC mutex prematurely and race with garbage collection */
1481 zbr = znode->zbranch[n];
1482 gc_seq1 = c->gc_seq;
1483 mutex_unlock(&c->tnc_mutex);
1484
1485 if (ubifs_get_wbuf(c, zbr.lnum)) {
1486 /* We do not GC journal heads */
1487 err = ubifs_tnc_read_node(c, &zbr, node);
1488 return err;
1489 }
1490
1491 err = fallible_read_node(c, key, &zbr, node);
1492 if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) {
1493 /*
1494 * The node may have been GC'ed out from under us so try again
1495 * while keeping the TNC mutex locked.
1496 */
1497 safely = 1;
1498 goto again;
1499 }
1500 return 0;
1501
1502out:
1503 mutex_unlock(&c->tnc_mutex);
1504 return err;
1505}
1506
1507/**
1508 * ubifs_tnc_get_bu_keys - lookup keys for bulk-read.
1509 * @c: UBIFS file-system description object
1510 * @bu: bulk-read parameters and results
1511 *
1512 * Lookup consecutive data node keys for the same inode that reside
1513 * consecutively in the same LEB. This function returns zero in case of success
1514 * and a negative error code in case of failure.
1515 *
1516 * Note, if the bulk-read buffer length (@bu->buf_len) is known, this function
1517 * makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares
1518 * maximum possible amount of nodes for bulk-read.
1519 */
1520int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)
1521{
1522 int n, err = 0, lnum = -1, uninitialized_var(offs);
1523 int uninitialized_var(len);
1524 unsigned int block = key_block(c, &bu->key);
1525 struct ubifs_znode *znode;
1526
1527 bu->cnt = 0;
1528 bu->blk_cnt = 0;
1529 bu->eof = 0;
1530
1531 mutex_lock(&c->tnc_mutex);
1532 /* Find first key */
1533 err = ubifs_lookup_level0(c, &bu->key, &znode, &n);
1534 if (err < 0)
1535 goto out;
1536 if (err) {
1537 /* Key found */
1538 len = znode->zbranch[n].len;
1539 /* The buffer must be big enough for at least 1 node */
1540 if (len > bu->buf_len) {
1541 err = -EINVAL;
1542 goto out;
1543 }
1544 /* Add this key */
1545 bu->zbranch[bu->cnt++] = znode->zbranch[n];
1546 bu->blk_cnt += 1;
1547 lnum = znode->zbranch[n].lnum;
1548 offs = ALIGN(znode->zbranch[n].offs + len, 8);
1549 }
1550 while (1) {
1551 struct ubifs_zbranch *zbr;
1552 union ubifs_key *key;
1553 unsigned int next_block;
1554
1555 /* Find next key */
1556 err = tnc_next(c, &znode, &n);
1557 if (err)
1558 goto out;
1559 zbr = &znode->zbranch[n];
1560 key = &zbr->key;
1561 /* See if there is another data key for this file */
1562 if (key_inum(c, key) != key_inum(c, &bu->key) ||
1563 key_type(c, key) != UBIFS_DATA_KEY) {
1564 err = -ENOENT;
1565 goto out;
1566 }
1567 if (lnum < 0) {
1568 /* First key found */
1569 lnum = zbr->lnum;
1570 offs = ALIGN(zbr->offs + zbr->len, 8);
1571 len = zbr->len;
1572 if (len > bu->buf_len) {
1573 err = -EINVAL;
1574 goto out;
1575 }
1576 } else {
1577 /*
1578 * The data nodes must be in consecutive positions in
1579 * the same LEB.
1580 */
1581 if (zbr->lnum != lnum || zbr->offs != offs)
1582 goto out;
1583 offs += ALIGN(zbr->len, 8);
1584 len = ALIGN(len, 8) + zbr->len;
1585 /* Must not exceed buffer length */
1586 if (len > bu->buf_len)
1587 goto out;
1588 }
1589 /* Allow for holes */
1590 next_block = key_block(c, key);
1591 bu->blk_cnt += (next_block - block - 1);
1592 if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
1593 goto out;
1594 block = next_block;
1595 /* Add this key */
1596 bu->zbranch[bu->cnt++] = *zbr;
1597 bu->blk_cnt += 1;
1598 /* See if we have room for more */
1599 if (bu->cnt >= UBIFS_MAX_BULK_READ)
1600 goto out;
1601 if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
1602 goto out;
1603 }
1604out:
1605 if (err == -ENOENT) {
1606 bu->eof = 1;
1607 err = 0;
1608 }
1609 bu->gc_seq = c->gc_seq;
1610 mutex_unlock(&c->tnc_mutex);
1611 if (err)
1612 return err;
1613 /*
1614 * An enormous hole could cause bulk-read to encompass too many
1615 * page cache pages, so limit the number here.
1616 */
1617 if (bu->blk_cnt > UBIFS_MAX_BULK_READ)
1618 bu->blk_cnt = UBIFS_MAX_BULK_READ;
1619 /*
1620 * Ensure that bulk-read covers a whole number of page cache
1621 * pages.
1622 */
1623 if (UBIFS_BLOCKS_PER_PAGE == 1 ||
1624 !(bu->blk_cnt & (UBIFS_BLOCKS_PER_PAGE - 1)))
1625 return 0;
1626 if (bu->eof) {
1627 /* At the end of file we can round up */
1628 bu->blk_cnt += UBIFS_BLOCKS_PER_PAGE - 1;
1629 return 0;
1630 }
1631 /* Exclude data nodes that do not make up a whole page cache page */
1632 block = key_block(c, &bu->key) + bu->blk_cnt;
1633 block &= ~(UBIFS_BLOCKS_PER_PAGE - 1);
1634 while (bu->cnt) {
1635 if (key_block(c, &bu->zbranch[bu->cnt - 1].key) < block)
1636 break;
1637 bu->cnt -= 1;
1638 }
1639 return 0;
1640}
1641
1642/**
1643 * read_wbuf - bulk-read from a LEB with a wbuf.
1644 * @wbuf: wbuf that may overlap the read
1645 * @buf: buffer into which to read
1646 * @len: read length
1647 * @lnum: LEB number from which to read
1648 * @offs: offset from which to read
1649 *
1650 * This functions returns %0 on success or a negative error code on failure.
1651 */
1652static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum,
1653 int offs)
1654{
1655 const struct ubifs_info *c = wbuf->c;
1656 int rlen, overlap;
1657
1658 dbg_io("LEB %d:%d, length %d", lnum, offs, len);
1659 ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
1660 ubifs_assert(!(offs & 7) && offs < c->leb_size);
1661 ubifs_assert(offs + len <= c->leb_size);
1662
1663 spin_lock(&wbuf->lock);
1664 overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
1665 if (!overlap) {
1666 /* We may safely unlock the write-buffer and read the data */
1667 spin_unlock(&wbuf->lock);
1668 return ubifs_leb_read(c, lnum, buf, offs, len, 0);
1669 }
1670
1671 /* Don't read under wbuf */
1672 rlen = wbuf->offs - offs;
1673 if (rlen < 0)
1674 rlen = 0;
1675
1676 /* Copy the rest from the write-buffer */
1677 memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
1678 spin_unlock(&wbuf->lock);
1679
1680 if (rlen > 0)
1681 /* Read everything that goes before write-buffer */
1682 return ubifs_leb_read(c, lnum, buf, offs, rlen, 0);
1683
1684 return 0;
1685}
1686
1687/**
1688 * validate_data_node - validate data nodes for bulk-read.
1689 * @c: UBIFS file-system description object
1690 * @buf: buffer containing data node to validate
1691 * @zbr: zbranch of data node to validate
1692 *
1693 * This functions returns %0 on success or a negative error code on failure.
1694 */
1695static int validate_data_node(struct ubifs_info *c, void *buf,
1696 struct ubifs_zbranch *zbr)
1697{
1698 union ubifs_key key1;
1699 struct ubifs_ch *ch = buf;
1700 int err, len;
1701
1702 if (ch->node_type != UBIFS_DATA_NODE) {
1703 ubifs_err("bad node type (%d but expected %d)",
1704 ch->node_type, UBIFS_DATA_NODE);
1705 goto out_err;
1706 }
1707
1708 err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0, 0);
1709 if (err) {
1710 ubifs_err("expected node type %d", UBIFS_DATA_NODE);
1711 goto out;
1712 }
1713
1714 len = le32_to_cpu(ch->len);
1715 if (len != zbr->len) {
1716 ubifs_err("bad node length %d, expected %d", len, zbr->len);
1717 goto out_err;
1718 }
1719
1720 /* Make sure the key of the read node is correct */
1721 key_read(c, buf + UBIFS_KEY_OFFSET, &key1);
1722 if (!keys_eq(c, &zbr->key, &key1)) {
1723 ubifs_err("bad key in node at LEB %d:%d",
1724 zbr->lnum, zbr->offs);
1725 dbg_tnck(&zbr->key, "looked for key ");
1726 dbg_tnck(&key1, "found node's key ");
1727 goto out_err;
1728 }
1729
1730 return 0;
1731
1732out_err:
1733 err = -EINVAL;
1734out:
1735 ubifs_err("bad node at LEB %d:%d", zbr->lnum, zbr->offs);
1736 ubifs_dump_node(c, buf);
1737 dump_stack();
1738 return err;
1739}
1740
1741/**
1742 * ubifs_tnc_bulk_read - read a number of data nodes in one go.
1743 * @c: UBIFS file-system description object
1744 * @bu: bulk-read parameters and results
1745 *
1746 * This functions reads and validates the data nodes that were identified by the
1747 * 'ubifs_tnc_get_bu_keys()' function. This functions returns %0 on success,
1748 * -EAGAIN to indicate a race with GC, or another negative error code on
1749 * failure.
1750 */
1751int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu)
1752{
1753 int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i;
1754 struct ubifs_wbuf *wbuf;
1755 void *buf;
1756
1757 len = bu->zbranch[bu->cnt - 1].offs;
1758 len += bu->zbranch[bu->cnt - 1].len - offs;
1759 if (len > bu->buf_len) {
1760 ubifs_err("buffer too small %d vs %d", bu->buf_len, len);
1761 return -EINVAL;
1762 }
1763
1764 /* Do the read */
1765 wbuf = ubifs_get_wbuf(c, lnum);
1766 if (wbuf)
1767 err = read_wbuf(wbuf, bu->buf, len, lnum, offs);
1768 else
1769 err = ubifs_leb_read(c, lnum, bu->buf, offs, len, 0);
1770
1771 /* Check for a race with GC */
1772 if (maybe_leb_gced(c, lnum, bu->gc_seq))
1773 return -EAGAIN;
1774
1775 if (err && err != -EBADMSG) {
1776 ubifs_err("failed to read from LEB %d:%d, error %d",
1777 lnum, offs, err);
1778 dump_stack();
1779 dbg_tnck(&bu->key, "key ");
1780 return err;
1781 }
1782
1783 /* Validate the nodes read */
1784 buf = bu->buf;
1785 for (i = 0; i < bu->cnt; i++) {
1786 err = validate_data_node(c, buf, &bu->zbranch[i]);
1787 if (err)
1788 return err;
1789 buf = buf + ALIGN(bu->zbranch[i].len, 8);
1790 }
1791
1792 return 0;
1793}
1794
1795/**
1796 * do_lookup_nm- look up a "hashed" node.
1797 * @c: UBIFS file-system description object
1798 * @key: node key to lookup
1799 * @node: the node is returned here
1800 * @nm: node name
1801 *
1802 * This function look up and reads a node which contains name hash in the key.
1803 * Since the hash may have collisions, there may be many nodes with the same
1804 * key, so we have to sequentially look to all of them until the needed one is
1805 * found. This function returns zero in case of success, %-ENOENT if the node
1806 * was not found, and a negative error code in case of failure.
1807 */
1808static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1809 void *node, const struct qstr *nm)
1810{
1811 int found, n, err;
1812 struct ubifs_znode *znode;
1813
1814 dbg_tnck(key, "name '%.*s' key ", nm->len, nm->name);
1815 mutex_lock(&c->tnc_mutex);
1816 found = ubifs_lookup_level0(c, key, &znode, &n);
1817 if (!found) {
1818 err = -ENOENT;
1819 goto out_unlock;
1820 } else if (found < 0) {
1821 err = found;
1822 goto out_unlock;
1823 }
1824
1825 ubifs_assert(n >= 0);
1826
1827 err = resolve_collision(c, key, &znode, &n, nm);
1828 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
1829 if (unlikely(err < 0))
1830 goto out_unlock;
1831 if (err == 0) {
1832 err = -ENOENT;
1833 goto out_unlock;
1834 }
1835
1836 err = tnc_read_node_nm(c, &znode->zbranch[n], node);
1837
1838out_unlock:
1839 mutex_unlock(&c->tnc_mutex);
1840 return err;
1841}
1842
1843/**
1844 * ubifs_tnc_lookup_nm - look up a "hashed" node.
1845 * @c: UBIFS file-system description object
1846 * @key: node key to lookup
1847 * @node: the node is returned here
1848 * @nm: node name
1849 *
1850 * This function look up and reads a node which contains name hash in the key.
1851 * Since the hash may have collisions, there may be many nodes with the same
1852 * key, so we have to sequentially look to all of them until the needed one is
1853 * found. This function returns zero in case of success, %-ENOENT if the node
1854 * was not found, and a negative error code in case of failure.
1855 */
1856int ubifs_tnc_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1857 void *node, const struct qstr *nm)
1858{
1859 int err, len;
1860 const struct ubifs_dent_node *dent = node;
1861
1862 /*
1863 * We assume that in most of the cases there are no name collisions and
1864 * 'ubifs_tnc_lookup()' returns us the right direntry.
1865 */
1866 err = ubifs_tnc_lookup(c, key, node);
1867 if (err)
1868 return err;
1869
1870 len = le16_to_cpu(dent->nlen);
1871 if (nm->len == len && !memcmp(dent->name, nm->name, len))
1872 return 0;
1873
1874 /*
1875 * Unluckily, there are hash collisions and we have to iterate over
1876 * them look at each direntry with colliding name hash sequentially.
1877 */
1878 return do_lookup_nm(c, key, node, nm);
1879}
1880
1881/**
1882 * correct_parent_keys - correct parent znodes' keys.
1883 * @c: UBIFS file-system description object
1884 * @znode: znode to correct parent znodes for
1885 *
1886 * This is a helper function for 'tnc_insert()'. When the key of the leftmost
1887 * zbranch changes, keys of parent znodes have to be corrected. This helper
1888 * function is called in such situations and corrects the keys if needed.
1889 */
1890static void correct_parent_keys(const struct ubifs_info *c,
1891 struct ubifs_znode *znode)
1892{
1893 union ubifs_key *key, *key1;
1894
1895 ubifs_assert(znode->parent);
1896 ubifs_assert(znode->iip == 0);
1897
1898 key = &znode->zbranch[0].key;
1899 key1 = &znode->parent->zbranch[0].key;
1900
1901 while (keys_cmp(c, key, key1) < 0) {
1902 key_copy(c, key, key1);
1903 znode = znode->parent;
1904 znode->alt = 1;
1905 if (!znode->parent || znode->iip)
1906 break;
1907 key1 = &znode->parent->zbranch[0].key;
1908 }
1909}
1910
1911/**
1912 * insert_zbranch - insert a zbranch into a znode.
1913 * @znode: znode into which to insert
1914 * @zbr: zbranch to insert
1915 * @n: slot number to insert to
1916 *
1917 * This is a helper function for 'tnc_insert()'. UBIFS does not allow "gaps" in
1918 * znode's array of zbranches and keeps zbranches consolidated, so when a new
1919 * zbranch has to be inserted to the @znode->zbranches[]' array at the @n-th
1920 * slot, zbranches starting from @n have to be moved right.
1921 */
1922static void insert_zbranch(struct ubifs_znode *znode,
1923 const struct ubifs_zbranch *zbr, int n)
1924{
1925 int i;
1926
1927 ubifs_assert(ubifs_zn_dirty(znode));
1928
1929 if (znode->level) {
1930 for (i = znode->child_cnt; i > n; i--) {
1931 znode->zbranch[i] = znode->zbranch[i - 1];
1932 if (znode->zbranch[i].znode)
1933 znode->zbranch[i].znode->iip = i;
1934 }
1935 if (zbr->znode)
1936 zbr->znode->iip = n;
1937 } else
1938 for (i = znode->child_cnt; i > n; i--)
1939 znode->zbranch[i] = znode->zbranch[i - 1];
1940
1941 znode->zbranch[n] = *zbr;
1942 znode->child_cnt += 1;
1943
1944 /*
1945 * After inserting at slot zero, the lower bound of the key range of
1946 * this znode may have changed. If this znode is subsequently split
1947 * then the upper bound of the key range may change, and furthermore
1948 * it could change to be lower than the original lower bound. If that
1949 * happens, then it will no longer be possible to find this znode in the
1950 * TNC using the key from the index node on flash. That is bad because
1951 * if it is not found, we will assume it is obsolete and may overwrite
1952 * it. Then if there is an unclean unmount, we will start using the
1953 * old index which will be broken.
1954 *
1955 * So we first mark znodes that have insertions at slot zero, and then
1956 * if they are split we add their lnum/offs to the old_idx tree.
1957 */
1958 if (n == 0)
1959 znode->alt = 1;
1960}
1961
1962/**
1963 * tnc_insert - insert a node into TNC.
1964 * @c: UBIFS file-system description object
1965 * @znode: znode to insert into
1966 * @zbr: branch to insert
1967 * @n: slot number to insert new zbranch to
1968 *
1969 * This function inserts a new node described by @zbr into znode @znode. If
1970 * znode does not have a free slot for new zbranch, it is split. Parent znodes
1971 * are splat as well if needed. Returns zero in case of success or a negative
1972 * error code in case of failure.
1973 */
1974static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode,
1975 struct ubifs_zbranch *zbr, int n)
1976{
1977 struct ubifs_znode *zn, *zi, *zp;
1978 int i, keep, move, appending = 0;
1979 union ubifs_key *key = &zbr->key, *key1;
1980
1981 ubifs_assert(n >= 0 && n <= c->fanout);
1982
1983 /* Implement naive insert for now */
1984again:
1985 zp = znode->parent;
1986 if (znode->child_cnt < c->fanout) {
1987 ubifs_assert(n != c->fanout);
1988 dbg_tnck(key, "inserted at %d level %d, key ", n, znode->level);
1989
1990 insert_zbranch(znode, zbr, n);
1991
1992 /* Ensure parent's key is correct */
1993 if (n == 0 && zp && znode->iip == 0)
1994 correct_parent_keys(c, znode);
1995
1996 return 0;
1997 }
1998
1999 /*
2000 * Unfortunately, @znode does not have more empty slots and we have to
2001 * split it.
2002 */
2003 dbg_tnck(key, "splitting level %d, key ", znode->level);
2004
2005 if (znode->alt)
2006 /*
2007 * We can no longer be sure of finding this znode by key, so we
2008 * record it in the old_idx tree.
2009 */
2010 ins_clr_old_idx_znode(c, znode);
2011
2012 zn = kzalloc(c->max_znode_sz, GFP_NOFS);
2013 if (!zn)
2014 return -ENOMEM;
2015 zn->parent = zp;
2016 zn->level = znode->level;
2017
2018 /* Decide where to split */
2019 if (znode->level == 0 && key_type(c, key) == UBIFS_DATA_KEY) {
2020 /* Try not to split consecutive data keys */
2021 if (n == c->fanout) {
2022 key1 = &znode->zbranch[n - 1].key;
2023 if (key_inum(c, key1) == key_inum(c, key) &&
2024 key_type(c, key1) == UBIFS_DATA_KEY)
2025 appending = 1;
2026 } else
2027 goto check_split;
2028 } else if (appending && n != c->fanout) {
2029 /* Try not to split consecutive data keys */
2030 appending = 0;
2031check_split:
2032 if (n >= (c->fanout + 1) / 2) {
2033 key1 = &znode->zbranch[0].key;
2034 if (key_inum(c, key1) == key_inum(c, key) &&
2035 key_type(c, key1) == UBIFS_DATA_KEY) {
2036 key1 = &znode->zbranch[n].key;
2037 if (key_inum(c, key1) != key_inum(c, key) ||
2038 key_type(c, key1) != UBIFS_DATA_KEY) {
2039 keep = n;
2040 move = c->fanout - keep;
2041 zi = znode;
2042 goto do_split;
2043 }
2044 }
2045 }
2046 }
2047
2048 if (appending) {
2049 keep = c->fanout;
2050 move = 0;
2051 } else {
2052 keep = (c->fanout + 1) / 2;
2053 move = c->fanout - keep;
2054 }
2055
2056 /*
2057 * Although we don't at present, we could look at the neighbors and see
2058 * if we can move some zbranches there.
2059 */
2060
2061 if (n < keep) {
2062 /* Insert into existing znode */
2063 zi = znode;
2064 move += 1;
2065 keep -= 1;
2066 } else {
2067 /* Insert into new znode */
2068 zi = zn;
2069 n -= keep;
2070 /* Re-parent */
2071 if (zn->level != 0)
2072 zbr->znode->parent = zn;
2073 }
2074
2075do_split:
2076
2077 __set_bit(DIRTY_ZNODE, &zn->flags);
2078 atomic_long_inc(&c->dirty_zn_cnt);
2079
2080 zn->child_cnt = move;
2081 znode->child_cnt = keep;
2082
2083 dbg_tnc("moving %d, keeping %d", move, keep);
2084
2085 /* Move zbranch */
2086 for (i = 0; i < move; i++) {
2087 zn->zbranch[i] = znode->zbranch[keep + i];
2088 /* Re-parent */
2089 if (zn->level != 0)
2090 if (zn->zbranch[i].znode) {
2091 zn->zbranch[i].znode->parent = zn;
2092 zn->zbranch[i].znode->iip = i;
2093 }
2094 }
2095
2096 /* Insert new key and branch */
2097 dbg_tnck(key, "inserting at %d level %d, key ", n, zn->level);
2098
2099 insert_zbranch(zi, zbr, n);
2100
2101 /* Insert new znode (produced by spitting) into the parent */
2102 if (zp) {
2103 if (n == 0 && zi == znode && znode->iip == 0)
2104 correct_parent_keys(c, znode);
2105
2106 /* Locate insertion point */
2107 n = znode->iip + 1;
2108
2109 /* Tail recursion */
2110 zbr->key = zn->zbranch[0].key;
2111 zbr->znode = zn;
2112 zbr->lnum = 0;
2113 zbr->offs = 0;
2114 zbr->len = 0;
2115 znode = zp;
2116
2117 goto again;
2118 }
2119
2120 /* We have to split root znode */
2121 dbg_tnc("creating new zroot at level %d", znode->level + 1);
2122
2123 zi = kzalloc(c->max_znode_sz, GFP_NOFS);
2124 if (!zi)
2125 return -ENOMEM;
2126
2127 zi->child_cnt = 2;
2128 zi->level = znode->level + 1;
2129
2130 __set_bit(DIRTY_ZNODE, &zi->flags);
2131 atomic_long_inc(&c->dirty_zn_cnt);
2132
2133 zi->zbranch[0].key = znode->zbranch[0].key;
2134 zi->zbranch[0].znode = znode;
2135 zi->zbranch[0].lnum = c->zroot.lnum;
2136 zi->zbranch[0].offs = c->zroot.offs;
2137 zi->zbranch[0].len = c->zroot.len;
2138 zi->zbranch[1].key = zn->zbranch[0].key;
2139 zi->zbranch[1].znode = zn;
2140
2141 c->zroot.lnum = 0;
2142 c->zroot.offs = 0;
2143 c->zroot.len = 0;
2144 c->zroot.znode = zi;
2145
2146 zn->parent = zi;
2147 zn->iip = 1;
2148 znode->parent = zi;
2149 znode->iip = 0;
2150
2151 return 0;
2152}
2153
2154/**
2155 * ubifs_tnc_add - add a node to TNC.
2156 * @c: UBIFS file-system description object
2157 * @key: key to add
2158 * @lnum: LEB number of node
2159 * @offs: node offset
2160 * @len: node length
2161 *
2162 * This function adds a node with key @key to TNC. The node may be new or it may
2163 * obsolete some existing one. Returns %0 on success or negative error code on
2164 * failure.
2165 */
2166int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum,
2167 int offs, int len)
2168{
2169 int found, n, err = 0;
2170 struct ubifs_znode *znode;
2171
2172 mutex_lock(&c->tnc_mutex);
2173 dbg_tnck(key, "%d:%d, len %d, key ", lnum, offs, len);
2174 found = lookup_level0_dirty(c, key, &znode, &n);
2175 if (!found) {
2176 struct ubifs_zbranch zbr;
2177
2178 zbr.znode = NULL;
2179 zbr.lnum = lnum;
2180 zbr.offs = offs;
2181 zbr.len = len;
2182 key_copy(c, key, &zbr.key);
2183 err = tnc_insert(c, znode, &zbr, n + 1);
2184 } else if (found == 1) {
2185 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2186
2187 lnc_free(zbr);
2188 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2189 zbr->lnum = lnum;
2190 zbr->offs = offs;
2191 zbr->len = len;
2192 } else
2193 err = found;
2194 if (!err)
2195 err = dbg_check_tnc(c, 0);
2196 mutex_unlock(&c->tnc_mutex);
2197
2198 return err;
2199}
2200
2201/**
2202 * ubifs_tnc_replace - replace a node in the TNC only if the old node is found.
2203 * @c: UBIFS file-system description object
2204 * @key: key to add
2205 * @old_lnum: LEB number of old node
2206 * @old_offs: old node offset
2207 * @lnum: LEB number of node
2208 * @offs: node offset
2209 * @len: node length
2210 *
2211 * This function replaces a node with key @key in the TNC only if the old node
2212 * is found. This function is called by garbage collection when node are moved.
2213 * Returns %0 on success or negative error code on failure.
2214 */
2215int ubifs_tnc_replace(struct ubifs_info *c, const union ubifs_key *key,
2216 int old_lnum, int old_offs, int lnum, int offs, int len)
2217{
2218 int found, n, err = 0;
2219 struct ubifs_znode *znode;
2220
2221 mutex_lock(&c->tnc_mutex);
2222 dbg_tnck(key, "old LEB %d:%d, new LEB %d:%d, len %d, key ", old_lnum,
2223 old_offs, lnum, offs, len);
2224 found = lookup_level0_dirty(c, key, &znode, &n);
2225 if (found < 0) {
2226 err = found;
2227 goto out_unlock;
2228 }
2229
2230 if (found == 1) {
2231 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2232
2233 found = 0;
2234 if (zbr->lnum == old_lnum && zbr->offs == old_offs) {
2235 lnc_free(zbr);
2236 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2237 if (err)
2238 goto out_unlock;
2239 zbr->lnum = lnum;
2240 zbr->offs = offs;
2241 zbr->len = len;
2242 found = 1;
2243 } else if (is_hash_key(c, key)) {
2244 found = resolve_collision_directly(c, key, &znode, &n,
2245 old_lnum, old_offs);
2246 dbg_tnc("rc returned %d, znode %p, n %d, LEB %d:%d",
2247 found, znode, n, old_lnum, old_offs);
2248 if (found < 0) {
2249 err = found;
2250 goto out_unlock;
2251 }
2252
2253 if (found) {
2254 /* Ensure the znode is dirtied */
2255 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2256 znode = dirty_cow_bottom_up(c, znode);
2257 if (IS_ERR(znode)) {
2258 err = PTR_ERR(znode);
2259 goto out_unlock;
2260 }
2261 }
2262 zbr = &znode->zbranch[n];
2263 lnc_free(zbr);
2264 err = ubifs_add_dirt(c, zbr->lnum,
2265 zbr->len);
2266 if (err)
2267 goto out_unlock;
2268 zbr->lnum = lnum;
2269 zbr->offs = offs;
2270 zbr->len = len;
2271 }
2272 }
2273 }
2274
2275 if (!found)
2276 err = ubifs_add_dirt(c, lnum, len);
2277
2278 if (!err)
2279 err = dbg_check_tnc(c, 0);
2280
2281out_unlock:
2282 mutex_unlock(&c->tnc_mutex);
2283 return err;
2284}
2285
2286/**
2287 * ubifs_tnc_add_nm - add a "hashed" node to TNC.
2288 * @c: UBIFS file-system description object
2289 * @key: key to add
2290 * @lnum: LEB number of node
2291 * @offs: node offset
2292 * @len: node length
2293 * @nm: node name
2294 *
2295 * This is the same as 'ubifs_tnc_add()' but it should be used with keys which
2296 * may have collisions, like directory entry keys.
2297 */
2298int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
2299 int lnum, int offs, int len, const struct qstr *nm)
2300{
2301 int found, n, err = 0;
2302 struct ubifs_znode *znode;
2303
2304 mutex_lock(&c->tnc_mutex);
2305 dbg_tnck(key, "LEB %d:%d, name '%.*s', key ",
2306 lnum, offs, nm->len, nm->name);
2307 found = lookup_level0_dirty(c, key, &znode, &n);
2308 if (found < 0) {
2309 err = found;
2310 goto out_unlock;
2311 }
2312
2313 if (found == 1) {
2314 if (c->replaying)
2315 found = fallible_resolve_collision(c, key, &znode, &n,
2316 nm, 1);
2317 else
2318 found = resolve_collision(c, key, &znode, &n, nm);
2319 dbg_tnc("rc returned %d, znode %p, n %d", found, znode, n);
2320 if (found < 0) {
2321 err = found;
2322 goto out_unlock;
2323 }
2324
2325 /* Ensure the znode is dirtied */
2326 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2327 znode = dirty_cow_bottom_up(c, znode);
2328 if (IS_ERR(znode)) {
2329 err = PTR_ERR(znode);
2330 goto out_unlock;
2331 }
2332 }
2333
2334 if (found == 1) {
2335 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2336
2337 lnc_free(zbr);
2338 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2339 zbr->lnum = lnum;
2340 zbr->offs = offs;
2341 zbr->len = len;
2342 goto out_unlock;
2343 }
2344 }
2345
2346 if (!found) {
2347 struct ubifs_zbranch zbr;
2348
2349 zbr.znode = NULL;
2350 zbr.lnum = lnum;
2351 zbr.offs = offs;
2352 zbr.len = len;
2353 key_copy(c, key, &zbr.key);
2354 err = tnc_insert(c, znode, &zbr, n + 1);
2355 if (err)
2356 goto out_unlock;
2357 if (c->replaying) {
2358 /*
2359 * We did not find it in the index so there may be a
2360 * dangling branch still in the index. So we remove it
2361 * by passing 'ubifs_tnc_remove_nm()' the same key but
2362 * an unmatchable name.
2363 */
2364 struct qstr noname = { .name = "" };
2365
2366 err = dbg_check_tnc(c, 0);
2367 mutex_unlock(&c->tnc_mutex);
2368 if (err)
2369 return err;
2370 return ubifs_tnc_remove_nm(c, key, &noname);
2371 }
2372 }
2373
2374out_unlock:
2375 if (!err)
2376 err = dbg_check_tnc(c, 0);
2377 mutex_unlock(&c->tnc_mutex);
2378 return err;
2379}
2380
2381/**
2382 * tnc_delete - delete a znode form TNC.
2383 * @c: UBIFS file-system description object
2384 * @znode: znode to delete from
2385 * @n: zbranch slot number to delete
2386 *
2387 * This function deletes a leaf node from @n-th slot of @znode. Returns zero in
2388 * case of success and a negative error code in case of failure.
2389 */
2390static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n)
2391{
2392 struct ubifs_zbranch *zbr;
2393 struct ubifs_znode *zp;
2394 int i, err;
2395
2396 /* Delete without merge for now */
2397 ubifs_assert(znode->level == 0);
2398 ubifs_assert(n >= 0 && n < c->fanout);
2399 dbg_tnck(&znode->zbranch[n].key, "deleting key ");
2400
2401 zbr = &znode->zbranch[n];
2402 lnc_free(zbr);
2403
2404 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2405 if (err) {
2406 ubifs_dump_znode(c, znode);
2407 return err;
2408 }
2409
2410 /* We do not "gap" zbranch slots */
2411 for (i = n; i < znode->child_cnt - 1; i++)
2412 znode->zbranch[i] = znode->zbranch[i + 1];
2413 znode->child_cnt -= 1;
2414
2415 if (znode->child_cnt > 0)
2416 return 0;
2417
2418 /*
2419 * This was the last zbranch, we have to delete this znode from the
2420 * parent.
2421 */
2422
2423 do {
2424 ubifs_assert(!ubifs_zn_obsolete(znode));
2425 ubifs_assert(ubifs_zn_dirty(znode));
2426
2427 zp = znode->parent;
2428 n = znode->iip;
2429
2430 atomic_long_dec(&c->dirty_zn_cnt);
2431
2432 err = insert_old_idx_znode(c, znode);
2433 if (err)
2434 return err;
2435
2436 if (znode->cnext) {
2437 __set_bit(OBSOLETE_ZNODE, &znode->flags);
2438 atomic_long_inc(&c->clean_zn_cnt);
2439 atomic_long_inc(&ubifs_clean_zn_cnt);
2440 } else
2441 kfree(znode);
2442 znode = zp;
2443 } while (znode->child_cnt == 1); /* while removing last child */
2444
2445 /* Remove from znode, entry n - 1 */
2446 znode->child_cnt -= 1;
2447 ubifs_assert(znode->level != 0);
2448 for (i = n; i < znode->child_cnt; i++) {
2449 znode->zbranch[i] = znode->zbranch[i + 1];
2450 if (znode->zbranch[i].znode)
2451 znode->zbranch[i].znode->iip = i;
2452 }
2453
2454 /*
2455 * If this is the root and it has only 1 child then
2456 * collapse the tree.
2457 */
2458 if (!znode->parent) {
2459 while (znode->child_cnt == 1 && znode->level != 0) {
2460 zp = znode;
2461 zbr = &znode->zbranch[0];
2462 znode = get_znode(c, znode, 0);
2463 if (IS_ERR(znode))
2464 return PTR_ERR(znode);
2465 znode = dirty_cow_znode(c, zbr);
2466 if (IS_ERR(znode))
2467 return PTR_ERR(znode);
2468 znode->parent = NULL;
2469 znode->iip = 0;
2470 if (c->zroot.len) {
2471 err = insert_old_idx(c, c->zroot.lnum,
2472 c->zroot.offs);
2473 if (err)
2474 return err;
2475 }
2476 c->zroot.lnum = zbr->lnum;
2477 c->zroot.offs = zbr->offs;
2478 c->zroot.len = zbr->len;
2479 c->zroot.znode = znode;
2480 ubifs_assert(!ubifs_zn_obsolete(zp));
2481 ubifs_assert(ubifs_zn_dirty(zp));
2482 atomic_long_dec(&c->dirty_zn_cnt);
2483
2484 if (zp->cnext) {
2485 __set_bit(OBSOLETE_ZNODE, &zp->flags);
2486 atomic_long_inc(&c->clean_zn_cnt);
2487 atomic_long_inc(&ubifs_clean_zn_cnt);
2488 } else
2489 kfree(zp);
2490 }
2491 }
2492
2493 return 0;
2494}
2495
2496/**
2497 * ubifs_tnc_remove - remove an index entry of a node.
2498 * @c: UBIFS file-system description object
2499 * @key: key of node
2500 *
2501 * Returns %0 on success or negative error code on failure.
2502 */
2503int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key)
2504{
2505 int found, n, err = 0;
2506 struct ubifs_znode *znode;
2507
2508 mutex_lock(&c->tnc_mutex);
2509 dbg_tnck(key, "key ");
2510 found = lookup_level0_dirty(c, key, &znode, &n);
2511 if (found < 0) {
2512 err = found;
2513 goto out_unlock;
2514 }
2515 if (found == 1)
2516 err = tnc_delete(c, znode, n);
2517 if (!err)
2518 err = dbg_check_tnc(c, 0);
2519
2520out_unlock:
2521 mutex_unlock(&c->tnc_mutex);
2522 return err;
2523}
2524
2525/**
2526 * ubifs_tnc_remove_nm - remove an index entry for a "hashed" node.
2527 * @c: UBIFS file-system description object
2528 * @key: key of node
2529 * @nm: directory entry name
2530 *
2531 * Returns %0 on success or negative error code on failure.
2532 */
2533int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
2534 const struct qstr *nm)
2535{
2536 int n, err;
2537 struct ubifs_znode *znode;
2538
2539 mutex_lock(&c->tnc_mutex);
2540 dbg_tnck(key, "%.*s, key ", nm->len, nm->name);
2541 err = lookup_level0_dirty(c, key, &znode, &n);
2542 if (err < 0)
2543 goto out_unlock;
2544
2545 if (err) {
2546 if (c->replaying)
2547 err = fallible_resolve_collision(c, key, &znode, &n,
2548 nm, 0);
2549 else
2550 err = resolve_collision(c, key, &znode, &n, nm);
2551 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
2552 if (err < 0)
2553 goto out_unlock;
2554 if (err) {
2555 /* Ensure the znode is dirtied */
2556 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2557 znode = dirty_cow_bottom_up(c, znode);
2558 if (IS_ERR(znode)) {
2559 err = PTR_ERR(znode);
2560 goto out_unlock;
2561 }
2562 }
2563 err = tnc_delete(c, znode, n);
2564 }
2565 }
2566
2567out_unlock:
2568 if (!err)
2569 err = dbg_check_tnc(c, 0);
2570 mutex_unlock(&c->tnc_mutex);
2571 return err;
2572}
2573
2574/**
2575 * key_in_range - determine if a key falls within a range of keys.
2576 * @c: UBIFS file-system description object
2577 * @key: key to check
2578 * @from_key: lowest key in range
2579 * @to_key: highest key in range
2580 *
2581 * This function returns %1 if the key is in range and %0 otherwise.
2582 */
2583static int key_in_range(struct ubifs_info *c, union ubifs_key *key,
2584 union ubifs_key *from_key, union ubifs_key *to_key)
2585{
2586 if (keys_cmp(c, key, from_key) < 0)
2587 return 0;
2588 if (keys_cmp(c, key, to_key) > 0)
2589 return 0;
2590 return 1;
2591}
2592
2593/**
2594 * ubifs_tnc_remove_range - remove index entries in range.
2595 * @c: UBIFS file-system description object
2596 * @from_key: lowest key to remove
2597 * @to_key: highest key to remove
2598 *
2599 * This function removes index entries starting at @from_key and ending at
2600 * @to_key. This function returns zero in case of success and a negative error
2601 * code in case of failure.
2602 */
2603int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key,
2604 union ubifs_key *to_key)
2605{
2606 int i, n, k, err = 0;
2607 struct ubifs_znode *znode;
2608 union ubifs_key *key;
2609
2610 mutex_lock(&c->tnc_mutex);
2611 while (1) {
2612 /* Find first level 0 znode that contains keys to remove */
2613 err = ubifs_lookup_level0(c, from_key, &znode, &n);
2614 if (err < 0)
2615 goto out_unlock;
2616
2617 if (err)
2618 key = from_key;
2619 else {
2620 err = tnc_next(c, &znode, &n);
2621 if (err == -ENOENT) {
2622 err = 0;
2623 goto out_unlock;
2624 }
2625 if (err < 0)
2626 goto out_unlock;
2627 key = &znode->zbranch[n].key;
2628 if (!key_in_range(c, key, from_key, to_key)) {
2629 err = 0;
2630 goto out_unlock;
2631 }
2632 }
2633
2634 /* Ensure the znode is dirtied */
2635 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2636 znode = dirty_cow_bottom_up(c, znode);
2637 if (IS_ERR(znode)) {
2638 err = PTR_ERR(znode);
2639 goto out_unlock;
2640 }
2641 }
2642
2643 /* Remove all keys in range except the first */
2644 for (i = n + 1, k = 0; i < znode->child_cnt; i++, k++) {
2645 key = &znode->zbranch[i].key;
2646 if (!key_in_range(c, key, from_key, to_key))
2647 break;
2648 lnc_free(&znode->zbranch[i]);
2649 err = ubifs_add_dirt(c, znode->zbranch[i].lnum,
2650 znode->zbranch[i].len);
2651 if (err) {
2652 ubifs_dump_znode(c, znode);
2653 goto out_unlock;
2654 }
2655 dbg_tnck(key, "removing key ");
2656 }
2657 if (k) {
2658 for (i = n + 1 + k; i < znode->child_cnt; i++)
2659 znode->zbranch[i - k] = znode->zbranch[i];
2660 znode->child_cnt -= k;
2661 }
2662
2663 /* Now delete the first */
2664 err = tnc_delete(c, znode, n);
2665 if (err)
2666 goto out_unlock;
2667 }
2668
2669out_unlock:
2670 if (!err)
2671 err = dbg_check_tnc(c, 0);
2672 mutex_unlock(&c->tnc_mutex);
2673 return err;
2674}
2675
2676/**
2677 * ubifs_tnc_remove_ino - remove an inode from TNC.
2678 * @c: UBIFS file-system description object
2679 * @inum: inode number to remove
2680 *
2681 * This function remove inode @inum and all the extended attributes associated
2682 * with the anode from TNC and returns zero in case of success or a negative
2683 * error code in case of failure.
2684 */
2685int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum)
2686{
2687 union ubifs_key key1, key2;
2688 struct ubifs_dent_node *xent, *pxent = NULL;
2689 struct qstr nm = { .name = NULL };
2690
2691 dbg_tnc("ino %lu", (unsigned long)inum);
2692
2693 /*
2694 * Walk all extended attribute entries and remove them together with
2695 * corresponding extended attribute inodes.
2696 */
2697 lowest_xent_key(c, &key1, inum);
2698 while (1) {
2699 ino_t xattr_inum;
2700 int err;
2701
2702 xent = ubifs_tnc_next_ent(c, &key1, &nm);
2703 if (IS_ERR(xent)) {
2704 err = PTR_ERR(xent);
2705 if (err == -ENOENT)
2706 break;
2707 return err;
2708 }
2709
2710 xattr_inum = le64_to_cpu(xent->inum);
2711 dbg_tnc("xent '%s', ino %lu", xent->name,
2712 (unsigned long)xattr_inum);
2713
2714 nm.name = xent->name;
2715 nm.len = le16_to_cpu(xent->nlen);
2716 err = ubifs_tnc_remove_nm(c, &key1, &nm);
2717 if (err) {
2718 kfree(xent);
2719 return err;
2720 }
2721
2722 lowest_ino_key(c, &key1, xattr_inum);
2723 highest_ino_key(c, &key2, xattr_inum);
2724 err = ubifs_tnc_remove_range(c, &key1, &key2);
2725 if (err) {
2726 kfree(xent);
2727 return err;
2728 }
2729
2730 kfree(pxent);
2731 pxent = xent;
2732 key_read(c, &xent->key, &key1);
2733 }
2734
2735 kfree(pxent);
2736 lowest_ino_key(c, &key1, inum);
2737 highest_ino_key(c, &key2, inum);
2738
2739 return ubifs_tnc_remove_range(c, &key1, &key2);
2740}
2741
2742/**
2743 * ubifs_tnc_next_ent - walk directory or extended attribute entries.
2744 * @c: UBIFS file-system description object
2745 * @key: key of last entry
2746 * @nm: name of last entry found or %NULL
2747 *
2748 * This function finds and reads the next directory or extended attribute entry
2749 * after the given key (@key) if there is one. @nm is used to resolve
2750 * collisions.
2751 *
2752 * If the name of the current entry is not known and only the key is known,
2753 * @nm->name has to be %NULL. In this case the semantics of this function is a
2754 * little bit different and it returns the entry corresponding to this key, not
2755 * the next one. If the key was not found, the closest "right" entry is
2756 * returned.
2757 *
2758 * If the fist entry has to be found, @key has to contain the lowest possible
2759 * key value for this inode and @name has to be %NULL.
2760 *
2761 * This function returns the found directory or extended attribute entry node
2762 * in case of success, %-ENOENT is returned if no entry was found, and a
2763 * negative error code is returned in case of failure.
2764 */
2765struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c,
2766 union ubifs_key *key,
2767 const struct qstr *nm)
2768{
2769 int n, err, type = key_type(c, key);
2770 struct ubifs_znode *znode;
2771 struct ubifs_dent_node *dent;
2772 struct ubifs_zbranch *zbr;
2773 union ubifs_key *dkey;
2774
2775 dbg_tnck(key, "%s ", nm->name ? (char *)nm->name : "(lowest)");
2776 ubifs_assert(is_hash_key(c, key));
2777
2778 mutex_lock(&c->tnc_mutex);
2779 err = ubifs_lookup_level0(c, key, &znode, &n);
2780 if (unlikely(err < 0))
2781 goto out_unlock;
2782
2783 if (nm->name) {
2784 if (err) {
2785 /* Handle collisions */
2786 err = resolve_collision(c, key, &znode, &n, nm);
2787 dbg_tnc("rc returned %d, znode %p, n %d",
2788 err, znode, n);
2789 if (unlikely(err < 0))
2790 goto out_unlock;
2791 }
2792
2793 /* Now find next entry */
2794 err = tnc_next(c, &znode, &n);
2795 if (unlikely(err))
2796 goto out_unlock;
2797 } else {
2798 /*
2799 * The full name of the entry was not given, in which case the
2800 * behavior of this function is a little different and it
2801 * returns current entry, not the next one.
2802 */
2803 if (!err) {
2804 /*
2805 * However, the given key does not exist in the TNC
2806 * tree and @znode/@n variables contain the closest
2807 * "preceding" element. Switch to the next one.
2808 */
2809 err = tnc_next(c, &znode, &n);
2810 if (err)
2811 goto out_unlock;
2812 }
2813 }
2814
2815 zbr = &znode->zbranch[n];
2816 dent = kmalloc(zbr->len, GFP_NOFS);
2817 if (unlikely(!dent)) {
2818 err = -ENOMEM;
2819 goto out_unlock;
2820 }
2821
2822 /*
2823 * The above 'tnc_next()' call could lead us to the next inode, check
2824 * this.
2825 */
2826 dkey = &zbr->key;
2827 if (key_inum(c, dkey) != key_inum(c, key) ||
2828 key_type(c, dkey) != type) {
2829 err = -ENOENT;
2830 goto out_free;
2831 }
2832
2833 err = tnc_read_node_nm(c, zbr, dent);
2834 if (unlikely(err))
2835 goto out_free;
2836
2837 mutex_unlock(&c->tnc_mutex);
2838 return dent;
2839
2840out_free:
2841 kfree(dent);
2842out_unlock:
2843 mutex_unlock(&c->tnc_mutex);
2844 return ERR_PTR(err);
2845}
2846
2847/**
2848 * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit.
2849 * @c: UBIFS file-system description object
2850 *
2851 * Destroy left-over obsolete znodes from a failed commit.
2852 */
2853static void tnc_destroy_cnext(struct ubifs_info *c)
2854{
2855 struct ubifs_znode *cnext;
2856
2857 if (!c->cnext)
2858 return;
2859 ubifs_assert(c->cmt_state == COMMIT_BROKEN);
2860 cnext = c->cnext;
2861 do {
2862 struct ubifs_znode *znode = cnext;
2863
2864 cnext = cnext->cnext;
2865 if (ubifs_zn_obsolete(znode))
2866 kfree(znode);
2867 } while (cnext && cnext != c->cnext);
2868}
2869
2870/**
2871 * ubifs_tnc_close - close TNC subsystem and free all related resources.
2872 * @c: UBIFS file-system description object
2873 */
2874void ubifs_tnc_close(struct ubifs_info *c)
2875{
2876 tnc_destroy_cnext(c);
2877 if (c->zroot.znode) {
2878 long n;
2879
2880 ubifs_destroy_tnc_subtree(c->zroot.znode);
2881 n = atomic_long_read(&c->clean_zn_cnt);
2882 atomic_long_sub(n, &ubifs_clean_zn_cnt);
2883 }
2884 kfree(c->gap_lebs);
2885 kfree(c->ilebs);
2886 destroy_old_idx(c);
2887}
2888
2889/**
2890 * left_znode - get the znode to the left.
2891 * @c: UBIFS file-system description object
2892 * @znode: znode
2893 *
2894 * This function returns a pointer to the znode to the left of @znode or NULL if
2895 * there is not one. A negative error code is returned on failure.
2896 */
2897static struct ubifs_znode *left_znode(struct ubifs_info *c,
2898 struct ubifs_znode *znode)
2899{
2900 int level = znode->level;
2901
2902 while (1) {
2903 int n = znode->iip - 1;
2904
2905 /* Go up until we can go left */
2906 znode = znode->parent;
2907 if (!znode)
2908 return NULL;
2909 if (n >= 0) {
2910 /* Now go down the rightmost branch to 'level' */
2911 znode = get_znode(c, znode, n);
2912 if (IS_ERR(znode))
2913 return znode;
2914 while (znode->level != level) {
2915 n = znode->child_cnt - 1;
2916 znode = get_znode(c, znode, n);
2917 if (IS_ERR(znode))
2918 return znode;
2919 }
2920 break;
2921 }
2922 }
2923 return znode;
2924}
2925
2926/**
2927 * right_znode - get the znode to the right.
2928 * @c: UBIFS file-system description object
2929 * @znode: znode
2930 *
2931 * This function returns a pointer to the znode to the right of @znode or NULL
2932 * if there is not one. A negative error code is returned on failure.
2933 */
2934static struct ubifs_znode *right_znode(struct ubifs_info *c,
2935 struct ubifs_znode *znode)
2936{
2937 int level = znode->level;
2938
2939 while (1) {
2940 int n = znode->iip + 1;
2941
2942 /* Go up until we can go right */
2943 znode = znode->parent;
2944 if (!znode)
2945 return NULL;
2946 if (n < znode->child_cnt) {
2947 /* Now go down the leftmost branch to 'level' */
2948 znode = get_znode(c, znode, n);
2949 if (IS_ERR(znode))
2950 return znode;
2951 while (znode->level != level) {
2952 znode = get_znode(c, znode, 0);
2953 if (IS_ERR(znode))
2954 return znode;
2955 }
2956 break;
2957 }
2958 }
2959 return znode;
2960}
2961
2962/**
2963 * lookup_znode - find a particular indexing node from TNC.
2964 * @c: UBIFS file-system description object
2965 * @key: index node key to lookup
2966 * @level: index node level
2967 * @lnum: index node LEB number
2968 * @offs: index node offset
2969 *
2970 * This function searches an indexing node by its first key @key and its
2971 * address @lnum:@offs. It looks up the indexing tree by pulling all indexing
2972 * nodes it traverses to TNC. This function is called for indexing nodes which
2973 * were found on the media by scanning, for example when garbage-collecting or
2974 * when doing in-the-gaps commit. This means that the indexing node which is
2975 * looked for does not have to have exactly the same leftmost key @key, because
2976 * the leftmost key may have been changed, in which case TNC will contain a
2977 * dirty znode which still refers the same @lnum:@offs. This function is clever
2978 * enough to recognize such indexing nodes.
2979 *
2980 * Note, if a znode was deleted or changed too much, then this function will
2981 * not find it. For situations like this UBIFS has the old index RB-tree
2982 * (indexed by @lnum:@offs).
2983 *
2984 * This function returns a pointer to the znode found or %NULL if it is not
2985 * found. A negative error code is returned on failure.
2986 */
2987static struct ubifs_znode *lookup_znode(struct ubifs_info *c,
2988 union ubifs_key *key, int level,
2989 int lnum, int offs)
2990{
2991 struct ubifs_znode *znode, *zn;
2992 int n, nn;
2993
2994 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
2995
2996 /*
2997 * The arguments have probably been read off flash, so don't assume
2998 * they are valid.
2999 */
3000 if (level < 0)
3001 return ERR_PTR(-EINVAL);
3002
3003 /* Get the root znode */
3004 znode = c->zroot.znode;
3005 if (!znode) {
3006 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
3007 if (IS_ERR(znode))
3008 return znode;
3009 }
3010 /* Check if it is the one we are looking for */
3011 if (c->zroot.lnum == lnum && c->zroot.offs == offs)
3012 return znode;
3013 /* Descend to the parent level i.e. (level + 1) */
3014 if (level >= znode->level)
3015 return NULL;
3016 while (1) {
3017 ubifs_search_zbranch(c, znode, key, &n);
3018 if (n < 0) {
3019 /*
3020 * We reached a znode where the leftmost key is greater
3021 * than the key we are searching for. This is the same
3022 * situation as the one described in a huge comment at
3023 * the end of the 'ubifs_lookup_level0()' function. And
3024 * for exactly the same reasons we have to try to look
3025 * left before giving up.
3026 */
3027 znode = left_znode(c, znode);
3028 if (!znode)
3029 return NULL;
3030 if (IS_ERR(znode))
3031 return znode;
3032 ubifs_search_zbranch(c, znode, key, &n);
3033 ubifs_assert(n >= 0);
3034 }
3035 if (znode->level == level + 1)
3036 break;
3037 znode = get_znode(c, znode, n);
3038 if (IS_ERR(znode))
3039 return znode;
3040 }
3041 /* Check if the child is the one we are looking for */
3042 if (znode->zbranch[n].lnum == lnum && znode->zbranch[n].offs == offs)
3043 return get_znode(c, znode, n);
3044 /* If the key is unique, there is nowhere else to look */
3045 if (!is_hash_key(c, key))
3046 return NULL;
3047 /*
3048 * The key is not unique and so may be also in the znodes to either
3049 * side.
3050 */
3051 zn = znode;
3052 nn = n;
3053 /* Look left */
3054 while (1) {
3055 /* Move one branch to the left */
3056 if (n)
3057 n -= 1;
3058 else {
3059 znode = left_znode(c, znode);
3060 if (!znode)
3061 break;
3062 if (IS_ERR(znode))
3063 return znode;
3064 n = znode->child_cnt - 1;
3065 }
3066 /* Check it */
3067 if (znode->zbranch[n].lnum == lnum &&
3068 znode->zbranch[n].offs == offs)
3069 return get_znode(c, znode, n);
3070 /* Stop if the key is less than the one we are looking for */
3071 if (keys_cmp(c, &znode->zbranch[n].key, key) < 0)
3072 break;
3073 }
3074 /* Back to the middle */
3075 znode = zn;
3076 n = nn;
3077 /* Look right */
3078 while (1) {
3079 /* Move one branch to the right */
3080 if (++n >= znode->child_cnt) {
3081 znode = right_znode(c, znode);
3082 if (!znode)
3083 break;
3084 if (IS_ERR(znode))
3085 return znode;
3086 n = 0;
3087 }
3088 /* Check it */
3089 if (znode->zbranch[n].lnum == lnum &&
3090 znode->zbranch[n].offs == offs)
3091 return get_znode(c, znode, n);
3092 /* Stop if the key is greater than the one we are looking for */
3093 if (keys_cmp(c, &znode->zbranch[n].key, key) > 0)
3094 break;
3095 }
3096 return NULL;
3097}
3098
3099/**
3100 * is_idx_node_in_tnc - determine if an index node is in the TNC.
3101 * @c: UBIFS file-system description object
3102 * @key: key of index node
3103 * @level: index node level
3104 * @lnum: LEB number of index node
3105 * @offs: offset of index node
3106 *
3107 * This function returns %0 if the index node is not referred to in the TNC, %1
3108 * if the index node is referred to in the TNC and the corresponding znode is
3109 * dirty, %2 if an index node is referred to in the TNC and the corresponding
3110 * znode is clean, and a negative error code in case of failure.
3111 *
3112 * Note, the @key argument has to be the key of the first child. Also note,
3113 * this function relies on the fact that 0:0 is never a valid LEB number and
3114 * offset for a main-area node.
3115 */
3116int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level,
3117 int lnum, int offs)
3118{
3119 struct ubifs_znode *znode;
3120
3121 znode = lookup_znode(c, key, level, lnum, offs);
3122 if (!znode)
3123 return 0;
3124 if (IS_ERR(znode))
3125 return PTR_ERR(znode);
3126
3127 return ubifs_zn_dirty(znode) ? 1 : 2;
3128}
3129
3130/**
3131 * is_leaf_node_in_tnc - determine if a non-indexing not is in the TNC.
3132 * @c: UBIFS file-system description object
3133 * @key: node key
3134 * @lnum: node LEB number
3135 * @offs: node offset
3136 *
3137 * This function returns %1 if the node is referred to in the TNC, %0 if it is
3138 * not, and a negative error code in case of failure.
3139 *
3140 * Note, this function relies on the fact that 0:0 is never a valid LEB number
3141 * and offset for a main-area node.
3142 */
3143static int is_leaf_node_in_tnc(struct ubifs_info *c, union ubifs_key *key,
3144 int lnum, int offs)
3145{
3146 struct ubifs_zbranch *zbr;
3147 struct ubifs_znode *znode, *zn;
3148 int n, found, err, nn;
3149 const int unique = !is_hash_key(c, key);
3150
3151 found = ubifs_lookup_level0(c, key, &znode, &n);
3152 if (found < 0)
3153 return found; /* Error code */
3154 if (!found)
3155 return 0;
3156 zbr = &znode->zbranch[n];
3157 if (lnum == zbr->lnum && offs == zbr->offs)
3158 return 1; /* Found it */
3159 if (unique)
3160 return 0;
3161 /*
3162 * Because the key is not unique, we have to look left
3163 * and right as well
3164 */
3165 zn = znode;
3166 nn = n;
3167 /* Look left */
3168 while (1) {
3169 err = tnc_prev(c, &znode, &n);
3170 if (err == -ENOENT)
3171 break;
3172 if (err)
3173 return err;
3174 if (keys_cmp(c, key, &znode->zbranch[n].key))
3175 break;
3176 zbr = &znode->zbranch[n];
3177 if (lnum == zbr->lnum && offs == zbr->offs)
3178 return 1; /* Found it */
3179 }
3180 /* Look right */
3181 znode = zn;
3182 n = nn;
3183 while (1) {
3184 err = tnc_next(c, &znode, &n);
3185 if (err) {
3186 if (err == -ENOENT)
3187 return 0;
3188 return err;
3189 }
3190 if (keys_cmp(c, key, &znode->zbranch[n].key))
3191 break;
3192 zbr = &znode->zbranch[n];
3193 if (lnum == zbr->lnum && offs == zbr->offs)
3194 return 1; /* Found it */
3195 }
3196 return 0;
3197}
3198
3199/**
3200 * ubifs_tnc_has_node - determine whether a node is in the TNC.
3201 * @c: UBIFS file-system description object
3202 * @key: node key
3203 * @level: index node level (if it is an index node)
3204 * @lnum: node LEB number
3205 * @offs: node offset
3206 * @is_idx: non-zero if the node is an index node
3207 *
3208 * This function returns %1 if the node is in the TNC, %0 if it is not, and a
3209 * negative error code in case of failure. For index nodes, @key has to be the
3210 * key of the first child. An index node is considered to be in the TNC only if
3211 * the corresponding znode is clean or has not been loaded.
3212 */
3213int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level,
3214 int lnum, int offs, int is_idx)
3215{
3216 int err;
3217
3218 mutex_lock(&c->tnc_mutex);
3219 if (is_idx) {
3220 err = is_idx_node_in_tnc(c, key, level, lnum, offs);
3221 if (err < 0)
3222 goto out_unlock;
3223 if (err == 1)
3224 /* The index node was found but it was dirty */
3225 err = 0;
3226 else if (err == 2)
3227 /* The index node was found and it was clean */
3228 err = 1;
3229 else
3230 BUG_ON(err != 0);
3231 } else
3232 err = is_leaf_node_in_tnc(c, key, lnum, offs);
3233
3234out_unlock:
3235 mutex_unlock(&c->tnc_mutex);
3236 return err;
3237}
3238
3239/**
3240 * ubifs_dirty_idx_node - dirty an index node.
3241 * @c: UBIFS file-system description object
3242 * @key: index node key
3243 * @level: index node level
3244 * @lnum: index node LEB number
3245 * @offs: index node offset
3246 *
3247 * This function loads and dirties an index node so that it can be garbage
3248 * collected. The @key argument has to be the key of the first child. This
3249 * function relies on the fact that 0:0 is never a valid LEB number and offset
3250 * for a main-area node. Returns %0 on success and a negative error code on
3251 * failure.
3252 */
3253int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level,
3254 int lnum, int offs)
3255{
3256 struct ubifs_znode *znode;
3257 int err = 0;
3258
3259 mutex_lock(&c->tnc_mutex);
3260 znode = lookup_znode(c, key, level, lnum, offs);
3261 if (!znode)
3262 goto out_unlock;
3263 if (IS_ERR(znode)) {
3264 err = PTR_ERR(znode);
3265 goto out_unlock;
3266 }
3267 znode = dirty_cow_bottom_up(c, znode);
3268 if (IS_ERR(znode)) {
3269 err = PTR_ERR(znode);
3270 goto out_unlock;
3271 }
3272
3273out_unlock:
3274 mutex_unlock(&c->tnc_mutex);
3275 return err;
3276}
3277
3278/**
3279 * dbg_check_inode_size - check if inode size is correct.
3280 * @c: UBIFS file-system description object
3281 * @inum: inode number
3282 * @size: inode size
3283 *
3284 * This function makes sure that the inode size (@size) is correct and it does
3285 * not have any pages beyond @size. Returns zero if the inode is OK, %-EINVAL
3286 * if it has a data page beyond @size, and other negative error code in case of
3287 * other errors.
3288 */
3289int dbg_check_inode_size(struct ubifs_info *c, const struct inode *inode,
3290 loff_t size)
3291{
3292 int err, n;
3293 union ubifs_key from_key, to_key, *key;
3294 struct ubifs_znode *znode;
3295 unsigned int block;
3296
3297 if (!S_ISREG(inode->i_mode))
3298 return 0;
3299 if (!dbg_is_chk_gen(c))
3300 return 0;
3301
3302 block = (size + UBIFS_BLOCK_SIZE - 1) >> UBIFS_BLOCK_SHIFT;
3303 data_key_init(c, &from_key, inode->i_ino, block);
3304 highest_data_key(c, &to_key, inode->i_ino);
3305
3306 mutex_lock(&c->tnc_mutex);
3307 err = ubifs_lookup_level0(c, &from_key, &znode, &n);
3308 if (err < 0)
3309 goto out_unlock;
3310
3311 if (err) {
3312 err = -EINVAL;
3313 key = &from_key;
3314 goto out_dump;
3315 }
3316
3317 err = tnc_next(c, &znode, &n);
3318 if (err == -ENOENT) {
3319 err = 0;
3320 goto out_unlock;
3321 }
3322 if (err < 0)
3323 goto out_unlock;
3324
3325 ubifs_assert(err == 0);
3326 key = &znode->zbranch[n].key;
3327 if (!key_in_range(c, key, &from_key, &to_key))
3328 goto out_unlock;
3329
3330out_dump:
3331 block = key_block(c, key);
3332 ubifs_err("inode %lu has size %lld, but there are data at offset %lld",
3333 (unsigned long)inode->i_ino, size,
3334 ((loff_t)block) << UBIFS_BLOCK_SHIFT);
3335 mutex_unlock(&c->tnc_mutex);
3336 ubifs_dump_inode(c, inode);
3337 dump_stack();
3338 return -EINVAL;
3339
3340out_unlock:
3341 mutex_unlock(&c->tnc_mutex);
3342 return err;
3343}