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Artem Bityutskiy1e517642008-07-14 19:08:37 +03001/*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * Authors: Adrian Hunter
20 * Artem Bityutskiy (Битюцкий Артём)
21 */
22
23/*
24 * This file implements TNC (Tree Node Cache) which caches indexing nodes of
25 * the UBIFS B-tree.
26 *
27 * At the moment the locking rules of the TNC tree are quite simple and
28 * straightforward. We just have a mutex and lock it when we traverse the
29 * tree. If a znode is not in memory, we read it from flash while still having
30 * the mutex locked.
31 */
32
33#include <linux/crc32.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090034#include <linux/slab.h>
Artem Bityutskiy1e517642008-07-14 19:08:37 +030035#include "ubifs.h"
36
37/*
38 * Returned codes of 'matches_name()' and 'fallible_matches_name()' functions.
39 * @NAME_LESS: name corresponding to the first argument is less than second
40 * @NAME_MATCHES: names match
41 * @NAME_GREATER: name corresponding to the second argument is greater than
42 * first
43 * @NOT_ON_MEDIA: node referred by zbranch does not exist on the media
44 *
45 * These constants were introduce to improve readability.
46 */
47enum {
48 NAME_LESS = 0,
49 NAME_MATCHES = 1,
50 NAME_GREATER = 2,
51 NOT_ON_MEDIA = 3,
52};
53
54/**
55 * insert_old_idx - record an index node obsoleted since the last commit start.
56 * @c: UBIFS file-system description object
57 * @lnum: LEB number of obsoleted index node
58 * @offs: offset of obsoleted index node
59 *
60 * Returns %0 on success, and a negative error code on failure.
61 *
62 * For recovery, there must always be a complete intact version of the index on
63 * flash at all times. That is called the "old index". It is the index as at the
64 * time of the last successful commit. Many of the index nodes in the old index
65 * may be dirty, but they must not be erased until the next successful commit
66 * (at which point that index becomes the old index).
67 *
68 * That means that the garbage collection and the in-the-gaps method of
69 * committing must be able to determine if an index node is in the old index.
70 * Most of the old index nodes can be found by looking up the TNC using the
71 * 'lookup_znode()' function. However, some of the old index nodes may have
72 * been deleted from the current index or may have been changed so much that
73 * they cannot be easily found. In those cases, an entry is added to an RB-tree.
74 * That is what this function does. The RB-tree is ordered by LEB number and
75 * offset because they uniquely identify the old index node.
76 */
77static int insert_old_idx(struct ubifs_info *c, int lnum, int offs)
78{
79 struct ubifs_old_idx *old_idx, *o;
80 struct rb_node **p, *parent = NULL;
81
82 old_idx = kmalloc(sizeof(struct ubifs_old_idx), GFP_NOFS);
83 if (unlikely(!old_idx))
84 return -ENOMEM;
85 old_idx->lnum = lnum;
86 old_idx->offs = offs;
87
88 p = &c->old_idx.rb_node;
89 while (*p) {
90 parent = *p;
91 o = rb_entry(parent, struct ubifs_old_idx, rb);
92 if (lnum < o->lnum)
93 p = &(*p)->rb_left;
94 else if (lnum > o->lnum)
95 p = &(*p)->rb_right;
96 else if (offs < o->offs)
97 p = &(*p)->rb_left;
98 else if (offs > o->offs)
99 p = &(*p)->rb_right;
100 else {
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(!test_bit(OBSOLETE_ZNODE, &znode->flags));
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 (!test_bit(COW_ZNODE, &znode->flags)) {
275 /* znode is not being committed */
276 if (!test_and_set_bit(DIRTY_ZNODE, &znode->flags)) {
277 atomic_long_inc(&c->dirty_zn_cnt);
278 atomic_long_dec(&c->clean_zn_cnt);
279 atomic_long_dec(&ubifs_clean_zn_cnt);
280 err = add_idx_dirt(c, zbr->lnum, zbr->len);
281 if (unlikely(err))
282 return ERR_PTR(err);
283 }
284 return znode;
285 }
286
287 zn = copy_znode(c, znode);
Hirofumi Nakagawa8d47aef2008-08-21 17:16:40 +0300288 if (IS_ERR(zn))
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300289 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.
Artem Bityutskiy6f7ab6d2009-01-27 16:12:31 +0200447 *
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->always_chk_crc is true, @c->no_chk_data_crc is ignored and CRC is always
451 * checked.
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300452 */
453static int try_read_node(const struct ubifs_info *c, void *buf, int type,
454 int len, int lnum, int offs)
455{
456 int err, node_len;
457 struct ubifs_ch *ch = buf;
458 uint32_t crc, node_crc;
459
460 dbg_io("LEB %d:%d, %s, length %d", lnum, offs, dbg_ntype(type), len);
461
462 err = ubi_read(c->ubi, lnum, buf, offs, len);
463 if (err) {
464 ubifs_err("cannot read node type %d from LEB %d:%d, error %d",
465 type, lnum, offs, err);
466 return err;
467 }
468
469 if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC)
470 return 0;
471
472 if (ch->node_type != type)
473 return 0;
474
475 node_len = le32_to_cpu(ch->len);
476 if (node_len != len)
477 return 0;
478
Artem Bityutskiy6f7ab6d2009-01-27 16:12:31 +0200479 if (type == UBIFS_DATA_NODE && !c->always_chk_crc && c->no_chk_data_crc)
480 return 1;
Adrian Hunter2953e732008-09-04 16:26:00 +0300481
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300482 crc = crc32(UBIFS_CRC32_INIT, buf + 8, node_len - 8);
483 node_crc = le32_to_cpu(ch->crc);
484 if (crc != node_crc)
485 return 0;
486
487 return 1;
488}
489
490/**
491 * fallible_read_node - try to read a leaf node.
492 * @c: UBIFS file-system description object
493 * @key: key of node to read
494 * @zbr: position of node
495 * @node: node returned
496 *
497 * This function tries to read a node and returns %1 if the node is read, %0
498 * if the node is not present, and a negative error code in the case of error.
499 */
500static int fallible_read_node(struct ubifs_info *c, const union ubifs_key *key,
501 struct ubifs_zbranch *zbr, void *node)
502{
503 int ret;
504
505 dbg_tnc("LEB %d:%d, key %s", zbr->lnum, zbr->offs, DBGKEY(key));
506
507 ret = try_read_node(c, node, key_type(c, key), zbr->len, zbr->lnum,
508 zbr->offs);
509 if (ret == 1) {
510 union ubifs_key node_key;
511 struct ubifs_dent_node *dent = node;
512
513 /* All nodes have key in the same place */
514 key_read(c, &dent->key, &node_key);
515 if (keys_cmp(c, key, &node_key) != 0)
516 ret = 0;
517 }
Adrian Hunter601c0bc2008-08-22 14:23:35 +0300518 if (ret == 0 && c->replaying)
Artem Bityutskiy1e517642008-07-14 19:08:37 +0300519 dbg_mnt("dangling branch LEB %d:%d len %d, key %s",
520 zbr->lnum, zbr->offs, zbr->len, DBGKEY(key));
521 return ret;
522}
523
524/**
525 * matches_name - determine if a direntry or xattr entry matches a given name.
526 * @c: UBIFS file-system description object
527 * @zbr: zbranch of dent
528 * @nm: name to match
529 *
530 * This function checks if xentry/direntry referred by zbranch @zbr matches name
531 * @nm. Returns %NAME_MATCHES if it does, %NAME_LESS if the name referred by
532 * @zbr is less than @nm, and %NAME_GREATER if it is greater than @nm. In case
533 * of failure, a negative error code is returned.
534 */
535static int matches_name(struct ubifs_info *c, struct ubifs_zbranch *zbr,
536 const struct qstr *nm)
537{
538 struct ubifs_dent_node *dent;
539 int nlen, err;
540
541 /* If possible, match against the dent in the leaf node cache */
542 if (!zbr->leaf) {
543 dent = kmalloc(zbr->len, GFP_NOFS);
544 if (!dent)
545 return -ENOMEM;
546
547 err = ubifs_tnc_read_node(c, zbr, dent);
548 if (err)
549 goto out_free;
550
551 /* Add the node to the leaf node cache */
552 err = lnc_add_directly(c, zbr, dent);
553 if (err)
554 goto out_free;
555 } else
556 dent = zbr->leaf;
557
558 nlen = le16_to_cpu(dent->nlen);
559 err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
560 if (err == 0) {
561 if (nlen == nm->len)
562 return NAME_MATCHES;
563 else if (nlen < nm->len)
564 return NAME_LESS;
565 else
566 return NAME_GREATER;
567 } else if (err < 0)
568 return NAME_LESS;
569 else
570 return NAME_GREATER;
571
572out_free:
573 kfree(dent);
574 return err;
575}
576
577/**
578 * get_znode - get a TNC znode that may not be loaded yet.
579 * @c: UBIFS file-system description object
580 * @znode: parent znode
581 * @n: znode branch slot number
582 *
583 * This function returns the znode or a negative error code.
584 */
585static struct ubifs_znode *get_znode(struct ubifs_info *c,
586 struct ubifs_znode *znode, int n)
587{
588 struct ubifs_zbranch *zbr;
589
590 zbr = &znode->zbranch[n];
591 if (zbr->znode)
592 znode = zbr->znode;
593 else
594 znode = ubifs_load_znode(c, zbr, znode, n);
595 return znode;
596}
597
598/**
599 * tnc_next - find next TNC entry.
600 * @c: UBIFS file-system description object
601 * @zn: znode is passed and returned here
602 * @n: znode branch slot number is passed and returned here
603 *
604 * This function returns %0 if the next TNC entry is found, %-ENOENT if there is
605 * no next entry, or a negative error code otherwise.
606 */
607static int tnc_next(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
608{
609 struct ubifs_znode *znode = *zn;
610 int nn = *n;
611
612 nn += 1;
613 if (nn < znode->child_cnt) {
614 *n = nn;
615 return 0;
616 }
617 while (1) {
618 struct ubifs_znode *zp;
619
620 zp = znode->parent;
621 if (!zp)
622 return -ENOENT;
623 nn = znode->iip + 1;
624 znode = zp;
625 if (nn < znode->child_cnt) {
626 znode = get_znode(c, znode, nn);
627 if (IS_ERR(znode))
628 return PTR_ERR(znode);
629 while (znode->level != 0) {
630 znode = get_znode(c, znode, 0);
631 if (IS_ERR(znode))
632 return PTR_ERR(znode);
633 }
634 nn = 0;
635 break;
636 }
637 }
638 *zn = znode;
639 *n = nn;
640 return 0;
641}
642
643/**
644 * tnc_prev - find previous TNC entry.
645 * @c: UBIFS file-system description object
646 * @zn: znode is returned here
647 * @n: znode branch slot number is passed and returned here
648 *
649 * This function returns %0 if the previous TNC entry is found, %-ENOENT if
650 * there is no next entry, or a negative error code otherwise.
651 */
652static int tnc_prev(struct ubifs_info *c, struct ubifs_znode **zn, int *n)
653{
654 struct ubifs_znode *znode = *zn;
655 int nn = *n;
656
657 if (nn > 0) {
658 *n = nn - 1;
659 return 0;
660 }
661 while (1) {
662 struct ubifs_znode *zp;
663
664 zp = znode->parent;
665 if (!zp)
666 return -ENOENT;
667 nn = znode->iip - 1;
668 znode = zp;
669 if (nn >= 0) {
670 znode = get_znode(c, znode, nn);
671 if (IS_ERR(znode))
672 return PTR_ERR(znode);
673 while (znode->level != 0) {
674 nn = znode->child_cnt - 1;
675 znode = get_znode(c, znode, nn);
676 if (IS_ERR(znode))
677 return PTR_ERR(znode);
678 }
679 nn = znode->child_cnt - 1;
680 break;
681 }
682 }
683 *zn = znode;
684 *n = nn;
685 return 0;
686}
687
688/**
689 * resolve_collision - resolve a collision.
690 * @c: UBIFS file-system description object
691 * @key: key of a directory or extended attribute entry
692 * @zn: znode is returned here
693 * @n: zbranch number is passed and returned here
694 * @nm: name of the entry
695 *
696 * This function is called for "hashed" keys to make sure that the found key
697 * really corresponds to the looked up node (directory or extended attribute
698 * entry). It returns %1 and sets @zn and @n if the collision is resolved.
699 * %0 is returned if @nm is not found and @zn and @n are set to the previous
700 * entry, i.e. to the entry after which @nm could follow if it were in TNC.
701 * This means that @n may be set to %-1 if the leftmost key in @zn is the
702 * previous one. A negative error code is returned on failures.
703 */
704static int resolve_collision(struct ubifs_info *c, const union ubifs_key *key,
705 struct ubifs_znode **zn, int *n,
706 const struct qstr *nm)
707{
708 int err;
709
710 err = matches_name(c, &(*zn)->zbranch[*n], nm);
711 if (unlikely(err < 0))
712 return err;
713 if (err == NAME_MATCHES)
714 return 1;
715
716 if (err == NAME_GREATER) {
717 /* Look left */
718 while (1) {
719 err = tnc_prev(c, zn, n);
720 if (err == -ENOENT) {
721 ubifs_assert(*n == 0);
722 *n = -1;
723 return 0;
724 }
725 if (err < 0)
726 return err;
727 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
728 /*
729 * We have found the branch after which we would
730 * like to insert, but inserting in this znode
731 * may still be wrong. Consider the following 3
732 * znodes, in the case where we are resolving a
733 * collision with Key2.
734 *
735 * znode zp
736 * ----------------------
737 * level 1 | Key0 | Key1 |
738 * -----------------------
739 * | |
740 * znode za | | znode zb
741 * ------------ ------------
742 * level 0 | Key0 | | Key2 |
743 * ------------ ------------
744 *
745 * The lookup finds Key2 in znode zb. Lets say
746 * there is no match and the name is greater so
747 * we look left. When we find Key0, we end up
748 * here. If we return now, we will insert into
749 * znode za at slot n = 1. But that is invalid
750 * according to the parent's keys. Key2 must
751 * be inserted into znode zb.
752 *
753 * Note, this problem is not relevant for the
754 * case when we go right, because
755 * 'tnc_insert()' would correct the parent key.
756 */
757 if (*n == (*zn)->child_cnt - 1) {
758 err = tnc_next(c, zn, n);
759 if (err) {
760 /* Should be impossible */
761 ubifs_assert(0);
762 if (err == -ENOENT)
763 err = -EINVAL;
764 return err;
765 }
766 ubifs_assert(*n == 0);
767 *n = -1;
768 }
769 return 0;
770 }
771 err = matches_name(c, &(*zn)->zbranch[*n], nm);
772 if (err < 0)
773 return err;
774 if (err == NAME_LESS)
775 return 0;
776 if (err == NAME_MATCHES)
777 return 1;
778 ubifs_assert(err == NAME_GREATER);
779 }
780 } else {
781 int nn = *n;
782 struct ubifs_znode *znode = *zn;
783
784 /* Look right */
785 while (1) {
786 err = tnc_next(c, &znode, &nn);
787 if (err == -ENOENT)
788 return 0;
789 if (err < 0)
790 return err;
791 if (keys_cmp(c, &znode->zbranch[nn].key, key))
792 return 0;
793 err = matches_name(c, &znode->zbranch[nn], nm);
794 if (err < 0)
795 return err;
796 if (err == NAME_GREATER)
797 return 0;
798 *zn = znode;
799 *n = nn;
800 if (err == NAME_MATCHES)
801 return 1;
802 ubifs_assert(err == NAME_LESS);
803 }
804 }
805}
806
807/**
808 * fallible_matches_name - determine if a dent matches a given name.
809 * @c: UBIFS file-system description object
810 * @zbr: zbranch of dent
811 * @nm: name to match
812 *
813 * This is a "fallible" version of 'matches_name()' function which does not
814 * panic if the direntry/xentry referred by @zbr does not exist on the media.
815 *
816 * This function checks if xentry/direntry referred by zbranch @zbr matches name
817 * @nm. Returns %NAME_MATCHES it does, %NAME_LESS if the name referred by @zbr
818 * is less than @nm, %NAME_GREATER if it is greater than @nm, and @NOT_ON_MEDIA
819 * if xentry/direntry referred by @zbr does not exist on the media. A negative
820 * error code is returned in case of failure.
821 */
822static int fallible_matches_name(struct ubifs_info *c,
823 struct ubifs_zbranch *zbr,
824 const struct qstr *nm)
825{
826 struct ubifs_dent_node *dent;
827 int nlen, err;
828
829 /* If possible, match against the dent in the leaf node cache */
830 if (!zbr->leaf) {
831 dent = kmalloc(zbr->len, GFP_NOFS);
832 if (!dent)
833 return -ENOMEM;
834
835 err = fallible_read_node(c, &zbr->key, zbr, dent);
836 if (err < 0)
837 goto out_free;
838 if (err == 0) {
839 /* The node was not present */
840 err = NOT_ON_MEDIA;
841 goto out_free;
842 }
843 ubifs_assert(err == 1);
844
845 err = lnc_add_directly(c, zbr, dent);
846 if (err)
847 goto out_free;
848 } else
849 dent = zbr->leaf;
850
851 nlen = le16_to_cpu(dent->nlen);
852 err = memcmp(dent->name, nm->name, min_t(int, nlen, nm->len));
853 if (err == 0) {
854 if (nlen == nm->len)
855 return NAME_MATCHES;
856 else if (nlen < nm->len)
857 return NAME_LESS;
858 else
859 return NAME_GREATER;
860 } else if (err < 0)
861 return NAME_LESS;
862 else
863 return NAME_GREATER;
864
865out_free:
866 kfree(dent);
867 return err;
868}
869
870/**
871 * fallible_resolve_collision - resolve a collision even if nodes are missing.
872 * @c: UBIFS file-system description object
873 * @key: key
874 * @zn: znode is returned here
875 * @n: branch number is passed and returned here
876 * @nm: name of directory entry
877 * @adding: indicates caller is adding a key to the TNC
878 *
879 * This is a "fallible" version of the 'resolve_collision()' function which
880 * does not panic if one of the nodes referred to by TNC does not exist on the
881 * media. This may happen when replaying the journal if a deleted node was
882 * Garbage-collected and the commit was not done. A branch that refers to a node
883 * that is not present is called a dangling branch. The following are the return
884 * codes for this function:
885 * o if @nm was found, %1 is returned and @zn and @n are set to the found
886 * branch;
887 * o if we are @adding and @nm was not found, %0 is returned;
888 * o if we are not @adding and @nm was not found, but a dangling branch was
889 * found, then %1 is returned and @zn and @n are set to the dangling branch;
890 * o a negative error code is returned in case of failure.
891 */
892static int fallible_resolve_collision(struct ubifs_info *c,
893 const union ubifs_key *key,
894 struct ubifs_znode **zn, int *n,
895 const struct qstr *nm, int adding)
896{
897 struct ubifs_znode *o_znode = NULL, *znode = *zn;
898 int uninitialized_var(o_n), err, cmp, unsure = 0, nn = *n;
899
900 cmp = fallible_matches_name(c, &znode->zbranch[nn], nm);
901 if (unlikely(cmp < 0))
902 return cmp;
903 if (cmp == NAME_MATCHES)
904 return 1;
905 if (cmp == NOT_ON_MEDIA) {
906 o_znode = znode;
907 o_n = nn;
908 /*
909 * We are unlucky and hit a dangling branch straight away.
910 * Now we do not really know where to go to find the needed
911 * branch - to the left or to the right. Well, let's try left.
912 */
913 unsure = 1;
914 } else if (!adding)
915 unsure = 1; /* Remove a dangling branch wherever it is */
916
917 if (cmp == NAME_GREATER || unsure) {
918 /* Look left */
919 while (1) {
920 err = tnc_prev(c, zn, n);
921 if (err == -ENOENT) {
922 ubifs_assert(*n == 0);
923 *n = -1;
924 break;
925 }
926 if (err < 0)
927 return err;
928 if (keys_cmp(c, &(*zn)->zbranch[*n].key, key)) {
929 /* See comments in 'resolve_collision()' */
930 if (*n == (*zn)->child_cnt - 1) {
931 err = tnc_next(c, zn, n);
932 if (err) {
933 /* Should be impossible */
934 ubifs_assert(0);
935 if (err == -ENOENT)
936 err = -EINVAL;
937 return err;
938 }
939 ubifs_assert(*n == 0);
940 *n = -1;
941 }
942 break;
943 }
944 err = fallible_matches_name(c, &(*zn)->zbranch[*n], nm);
945 if (err < 0)
946 return err;
947 if (err == NAME_MATCHES)
948 return 1;
949 if (err == NOT_ON_MEDIA) {
950 o_znode = *zn;
951 o_n = *n;
952 continue;
953 }
954 if (!adding)
955 continue;
956 if (err == NAME_LESS)
957 break;
958 else
959 unsure = 0;
960 }
961 }
962
963 if (cmp == NAME_LESS || unsure) {
964 /* Look right */
965 *zn = znode;
966 *n = nn;
967 while (1) {
968 err = tnc_next(c, &znode, &nn);
969 if (err == -ENOENT)
970 break;
971 if (err < 0)
972 return err;
973 if (keys_cmp(c, &znode->zbranch[nn].key, key))
974 break;
975 err = fallible_matches_name(c, &znode->zbranch[nn], nm);
976 if (err < 0)
977 return err;
978 if (err == NAME_GREATER)
979 break;
980 *zn = znode;
981 *n = nn;
982 if (err == NAME_MATCHES)
983 return 1;
984 if (err == NOT_ON_MEDIA) {
985 o_znode = znode;
986 o_n = nn;
987 }
988 }
989 }
990
991 /* Never match a dangling branch when adding */
992 if (adding || !o_znode)
993 return 0;
994
995 dbg_mnt("dangling match LEB %d:%d len %d %s",
996 o_znode->zbranch[o_n].lnum, o_znode->zbranch[o_n].offs,
997 o_znode->zbranch[o_n].len, DBGKEY(key));
998 *zn = o_znode;
999 *n = o_n;
1000 return 1;
1001}
1002
1003/**
1004 * matches_position - determine if a zbranch matches a given position.
1005 * @zbr: zbranch of dent
1006 * @lnum: LEB number of dent to match
1007 * @offs: offset of dent to match
1008 *
1009 * This function returns %1 if @lnum:@offs matches, and %0 otherwise.
1010 */
1011static int matches_position(struct ubifs_zbranch *zbr, int lnum, int offs)
1012{
1013 if (zbr->lnum == lnum && zbr->offs == offs)
1014 return 1;
1015 else
1016 return 0;
1017}
1018
1019/**
1020 * resolve_collision_directly - resolve a collision directly.
1021 * @c: UBIFS file-system description object
1022 * @key: key of directory entry
1023 * @zn: znode is passed and returned here
1024 * @n: zbranch number is passed and returned here
1025 * @lnum: LEB number of dent node to match
1026 * @offs: offset of dent node to match
1027 *
1028 * This function is used for "hashed" keys to make sure the found directory or
1029 * extended attribute entry node is what was looked for. It is used when the
1030 * flash address of the right node is known (@lnum:@offs) which makes it much
1031 * easier to resolve collisions (no need to read entries and match full
1032 * names). This function returns %1 and sets @zn and @n if the collision is
1033 * resolved, %0 if @lnum:@offs is not found and @zn and @n are set to the
1034 * previous directory entry. Otherwise a negative error code is returned.
1035 */
1036static int resolve_collision_directly(struct ubifs_info *c,
1037 const union ubifs_key *key,
1038 struct ubifs_znode **zn, int *n,
1039 int lnum, int offs)
1040{
1041 struct ubifs_znode *znode;
1042 int nn, err;
1043
1044 znode = *zn;
1045 nn = *n;
1046 if (matches_position(&znode->zbranch[nn], lnum, offs))
1047 return 1;
1048
1049 /* Look left */
1050 while (1) {
1051 err = tnc_prev(c, &znode, &nn);
1052 if (err == -ENOENT)
1053 break;
1054 if (err < 0)
1055 return err;
1056 if (keys_cmp(c, &znode->zbranch[nn].key, key))
1057 break;
1058 if (matches_position(&znode->zbranch[nn], lnum, offs)) {
1059 *zn = znode;
1060 *n = nn;
1061 return 1;
1062 }
1063 }
1064
1065 /* Look right */
1066 znode = *zn;
1067 nn = *n;
1068 while (1) {
1069 err = tnc_next(c, &znode, &nn);
1070 if (err == -ENOENT)
1071 return 0;
1072 if (err < 0)
1073 return err;
1074 if (keys_cmp(c, &znode->zbranch[nn].key, key))
1075 return 0;
1076 *zn = znode;
1077 *n = nn;
1078 if (matches_position(&znode->zbranch[nn], lnum, offs))
1079 return 1;
1080 }
1081}
1082
1083/**
1084 * dirty_cow_bottom_up - dirty a znode and its ancestors.
1085 * @c: UBIFS file-system description object
1086 * @znode: znode to dirty
1087 *
1088 * If we do not have a unique key that resides in a znode, then we cannot
1089 * dirty that znode from the top down (i.e. by using lookup_level0_dirty)
1090 * This function records the path back to the last dirty ancestor, and then
1091 * dirties the znodes on that path.
1092 */
1093static struct ubifs_znode *dirty_cow_bottom_up(struct ubifs_info *c,
1094 struct ubifs_znode *znode)
1095{
1096 struct ubifs_znode *zp;
1097 int *path = c->bottom_up_buf, p = 0;
1098
1099 ubifs_assert(c->zroot.znode);
1100 ubifs_assert(znode);
1101 if (c->zroot.znode->level > BOTTOM_UP_HEIGHT) {
1102 kfree(c->bottom_up_buf);
1103 c->bottom_up_buf = kmalloc(c->zroot.znode->level * sizeof(int),
1104 GFP_NOFS);
1105 if (!c->bottom_up_buf)
1106 return ERR_PTR(-ENOMEM);
1107 path = c->bottom_up_buf;
1108 }
1109 if (c->zroot.znode->level) {
1110 /* Go up until parent is dirty */
1111 while (1) {
1112 int n;
1113
1114 zp = znode->parent;
1115 if (!zp)
1116 break;
1117 n = znode->iip;
1118 ubifs_assert(p < c->zroot.znode->level);
1119 path[p++] = n;
1120 if (!zp->cnext && ubifs_zn_dirty(znode))
1121 break;
1122 znode = zp;
1123 }
1124 }
1125
1126 /* Come back down, dirtying as we go */
1127 while (1) {
1128 struct ubifs_zbranch *zbr;
1129
1130 zp = znode->parent;
1131 if (zp) {
1132 ubifs_assert(path[p - 1] >= 0);
1133 ubifs_assert(path[p - 1] < zp->child_cnt);
1134 zbr = &zp->zbranch[path[--p]];
1135 znode = dirty_cow_znode(c, zbr);
1136 } else {
1137 ubifs_assert(znode == c->zroot.znode);
1138 znode = dirty_cow_znode(c, &c->zroot);
1139 }
Hirofumi Nakagawa8d47aef2008-08-21 17:16:40 +03001140 if (IS_ERR(znode) || !p)
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001141 break;
1142 ubifs_assert(path[p - 1] >= 0);
1143 ubifs_assert(path[p - 1] < znode->child_cnt);
1144 znode = znode->zbranch[path[p - 1]].znode;
1145 }
1146
1147 return znode;
1148}
1149
1150/**
1151 * ubifs_lookup_level0 - search for zero-level znode.
1152 * @c: UBIFS file-system description object
1153 * @key: key to lookup
1154 * @zn: znode is returned here
1155 * @n: znode branch slot number is returned here
1156 *
1157 * This function looks up the TNC tree and search for zero-level znode which
1158 * refers key @key. The found zero-level znode is returned in @zn. There are 3
1159 * cases:
1160 * o exact match, i.e. the found zero-level znode contains key @key, then %1
1161 * is returned and slot number of the matched branch is stored in @n;
1162 * o not exact match, which means that zero-level znode does not contain
Artem Bityutskiye3c3efc2009-08-27 16:34:19 +03001163 * @key, then %0 is returned and slot number of the closest branch is stored
1164 * in @n;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001165 * o @key is so small that it is even less than the lowest key of the
1166 * leftmost zero-level node, then %0 is returned and %0 is stored in @n.
1167 *
1168 * Note, when the TNC tree is traversed, some znodes may be absent, then this
1169 * function reads corresponding indexing nodes and inserts them to TNC. In
1170 * case of failure, a negative error code is returned.
1171 */
1172int ubifs_lookup_level0(struct ubifs_info *c, const union ubifs_key *key,
1173 struct ubifs_znode **zn, int *n)
1174{
1175 int err, exact;
1176 struct ubifs_znode *znode;
1177 unsigned long time = get_seconds();
1178
1179 dbg_tnc("search key %s", DBGKEY(key));
Artem Bityutskiyba2f48f2010-08-22 07:10:12 +03001180 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001181
1182 znode = c->zroot.znode;
1183 if (unlikely(!znode)) {
1184 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
1185 if (IS_ERR(znode))
1186 return PTR_ERR(znode);
1187 }
1188
1189 znode->time = time;
1190
1191 while (1) {
1192 struct ubifs_zbranch *zbr;
1193
1194 exact = ubifs_search_zbranch(c, znode, key, n);
1195
1196 if (znode->level == 0)
1197 break;
1198
1199 if (*n < 0)
1200 *n = 0;
1201 zbr = &znode->zbranch[*n];
1202
1203 if (zbr->znode) {
1204 znode->time = time;
1205 znode = zbr->znode;
1206 continue;
1207 }
1208
1209 /* znode is not in TNC cache, load it from the media */
1210 znode = ubifs_load_znode(c, zbr, znode, *n);
1211 if (IS_ERR(znode))
1212 return PTR_ERR(znode);
1213 }
1214
1215 *zn = znode;
1216 if (exact || !is_hash_key(c, key) || *n != -1) {
1217 dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
1218 return exact;
1219 }
1220
1221 /*
1222 * Here is a tricky place. We have not found the key and this is a
1223 * "hashed" key, which may collide. The rest of the code deals with
1224 * situations like this:
1225 *
1226 * | 3 | 5 |
1227 * / \
1228 * | 3 | 5 | | 6 | 7 | (x)
1229 *
1230 * Or more a complex example:
1231 *
1232 * | 1 | 5 |
1233 * / \
1234 * | 1 | 3 | | 5 | 8 |
1235 * \ /
1236 * | 5 | 5 | | 6 | 7 | (x)
1237 *
1238 * In the examples, if we are looking for key "5", we may reach nodes
1239 * marked with "(x)". In this case what we have do is to look at the
1240 * left and see if there is "5" key there. If there is, we have to
1241 * return it.
1242 *
1243 * Note, this whole situation is possible because we allow to have
1244 * elements which are equivalent to the next key in the parent in the
1245 * children of current znode. For example, this happens if we split a
1246 * znode like this: | 3 | 5 | 5 | 6 | 7 |, which results in something
1247 * like this:
1248 * | 3 | 5 |
1249 * / \
1250 * | 3 | 5 | | 5 | 6 | 7 |
1251 * ^
1252 * And this becomes what is at the first "picture" after key "5" marked
1253 * with "^" is removed. What could be done is we could prohibit
1254 * splitting in the middle of the colliding sequence. Also, when
1255 * removing the leftmost key, we would have to correct the key of the
1256 * parent node, which would introduce additional complications. Namely,
Artem Bityutskiy7d4e9cc2009-03-20 19:11:12 +02001257 * if we changed the leftmost key of the parent znode, the garbage
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001258 * collector would be unable to find it (GC is doing this when GC'ing
1259 * indexing LEBs). Although we already have an additional RB-tree where
1260 * we save such changed znodes (see 'ins_clr_old_idx_znode()') until
1261 * after the commit. But anyway, this does not look easy to implement
1262 * so we did not try this.
1263 */
1264 err = tnc_prev(c, &znode, n);
1265 if (err == -ENOENT) {
1266 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1267 *n = -1;
1268 return 0;
1269 }
1270 if (unlikely(err < 0))
1271 return err;
1272 if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
1273 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1274 *n = -1;
1275 return 0;
1276 }
1277
1278 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1279 *zn = znode;
1280 return 1;
1281}
1282
1283/**
1284 * lookup_level0_dirty - search for zero-level znode dirtying.
1285 * @c: UBIFS file-system description object
1286 * @key: key to lookup
1287 * @zn: znode is returned here
1288 * @n: znode branch slot number is returned here
1289 *
1290 * This function looks up the TNC tree and search for zero-level znode which
1291 * refers key @key. The found zero-level znode is returned in @zn. There are 3
1292 * cases:
1293 * o exact match, i.e. the found zero-level znode contains key @key, then %1
1294 * is returned and slot number of the matched branch is stored in @n;
1295 * o not exact match, which means that zero-level znode does not contain @key
1296 * then %0 is returned and slot number of the closed branch is stored in
1297 * @n;
1298 * o @key is so small that it is even less than the lowest key of the
1299 * leftmost zero-level node, then %0 is returned and %-1 is stored in @n.
1300 *
1301 * Additionally all znodes in the path from the root to the located zero-level
1302 * znode are marked as dirty.
1303 *
1304 * Note, when the TNC tree is traversed, some znodes may be absent, then this
1305 * function reads corresponding indexing nodes and inserts them to TNC. In
1306 * case of failure, a negative error code is returned.
1307 */
1308static int lookup_level0_dirty(struct ubifs_info *c, const union ubifs_key *key,
1309 struct ubifs_znode **zn, int *n)
1310{
1311 int err, exact;
1312 struct ubifs_znode *znode;
1313 unsigned long time = get_seconds();
1314
1315 dbg_tnc("search and dirty key %s", DBGKEY(key));
1316
1317 znode = c->zroot.znode;
1318 if (unlikely(!znode)) {
1319 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
1320 if (IS_ERR(znode))
1321 return PTR_ERR(znode);
1322 }
1323
1324 znode = dirty_cow_znode(c, &c->zroot);
1325 if (IS_ERR(znode))
1326 return PTR_ERR(znode);
1327
1328 znode->time = time;
1329
1330 while (1) {
1331 struct ubifs_zbranch *zbr;
1332
1333 exact = ubifs_search_zbranch(c, znode, key, n);
1334
1335 if (znode->level == 0)
1336 break;
1337
1338 if (*n < 0)
1339 *n = 0;
1340 zbr = &znode->zbranch[*n];
1341
1342 if (zbr->znode) {
1343 znode->time = time;
1344 znode = dirty_cow_znode(c, zbr);
1345 if (IS_ERR(znode))
1346 return PTR_ERR(znode);
1347 continue;
1348 }
1349
1350 /* znode is not in TNC cache, load it from the media */
1351 znode = ubifs_load_znode(c, zbr, znode, *n);
1352 if (IS_ERR(znode))
1353 return PTR_ERR(znode);
1354 znode = dirty_cow_znode(c, zbr);
1355 if (IS_ERR(znode))
1356 return PTR_ERR(znode);
1357 }
1358
1359 *zn = znode;
1360 if (exact || !is_hash_key(c, key) || *n != -1) {
1361 dbg_tnc("found %d, lvl %d, n %d", exact, znode->level, *n);
1362 return exact;
1363 }
1364
1365 /*
1366 * See huge comment at 'lookup_level0_dirty()' what is the rest of the
1367 * code.
1368 */
1369 err = tnc_prev(c, &znode, n);
1370 if (err == -ENOENT) {
1371 *n = -1;
1372 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1373 return 0;
1374 }
1375 if (unlikely(err < 0))
1376 return err;
1377 if (keys_cmp(c, key, &znode->zbranch[*n].key)) {
1378 *n = -1;
1379 dbg_tnc("found 0, lvl %d, n -1", znode->level);
1380 return 0;
1381 }
1382
1383 if (znode->cnext || !ubifs_zn_dirty(znode)) {
1384 znode = dirty_cow_bottom_up(c, znode);
1385 if (IS_ERR(znode))
1386 return PTR_ERR(znode);
1387 }
1388
1389 dbg_tnc("found 1, lvl %d, n %d", znode->level, *n);
1390 *zn = znode;
1391 return 1;
1392}
1393
1394/**
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001395 * maybe_leb_gced - determine if a LEB may have been garbage collected.
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001396 * @c: UBIFS file-system description object
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001397 * @lnum: LEB number
1398 * @gc_seq1: garbage collection sequence number
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001399 *
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001400 * This function determines if @lnum may have been garbage collected since
1401 * sequence number @gc_seq1. If it may have been then %1 is returned, otherwise
1402 * %0 is returned.
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001403 */
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001404static int maybe_leb_gced(struct ubifs_info *c, int lnum, int gc_seq1)
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001405{
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001406 int gc_seq2, gced_lnum;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001407
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001408 gced_lnum = c->gced_lnum;
1409 smp_rmb();
1410 gc_seq2 = c->gc_seq;
1411 /* Same seq means no GC */
1412 if (gc_seq1 == gc_seq2)
1413 return 0;
1414 /* Different by more than 1 means we don't know */
1415 if (gc_seq1 + 1 != gc_seq2)
1416 return 1;
1417 /*
1418 * We have seen the sequence number has increased by 1. Now we need to
1419 * be sure we read the right LEB number, so read it again.
1420 */
1421 smp_rmb();
1422 if (gced_lnum != c->gced_lnum)
1423 return 1;
1424 /* Finally we can check lnum */
1425 if (gced_lnum == lnum)
1426 return 1;
1427 return 0;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001428}
1429
1430/**
1431 * ubifs_tnc_locate - look up a file-system node and return it and its location.
1432 * @c: UBIFS file-system description object
1433 * @key: node key to lookup
1434 * @node: the node is returned here
1435 * @lnum: LEB number is returned here
1436 * @offs: offset is returned here
1437 *
Artem Bityutskiye3c3efc2009-08-27 16:34:19 +03001438 * This function looks up and reads node with key @key. The caller has to make
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001439 * sure the @node buffer is large enough to fit the node. Returns zero in case
1440 * of success, %-ENOENT if the node was not found, and a negative error code in
1441 * case of failure. The node location can be returned in @lnum and @offs.
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001442 */
1443int ubifs_tnc_locate(struct ubifs_info *c, const union ubifs_key *key,
1444 void *node, int *lnum, int *offs)
1445{
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001446 int found, n, err, safely = 0, gc_seq1;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001447 struct ubifs_znode *znode;
1448 struct ubifs_zbranch zbr, *zt;
1449
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001450again:
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001451 mutex_lock(&c->tnc_mutex);
1452 found = ubifs_lookup_level0(c, key, &znode, &n);
1453 if (!found) {
1454 err = -ENOENT;
1455 goto out;
1456 } else if (found < 0) {
1457 err = found;
1458 goto out;
1459 }
1460 zt = &znode->zbranch[n];
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001461 if (lnum) {
1462 *lnum = zt->lnum;
1463 *offs = zt->offs;
1464 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001465 if (is_hash_key(c, key)) {
1466 /*
1467 * In this case the leaf node cache gets used, so we pass the
1468 * address of the zbranch and keep the mutex locked
1469 */
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001470 err = tnc_read_node_nm(c, zt, node);
1471 goto out;
1472 }
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001473 if (safely) {
1474 err = ubifs_tnc_read_node(c, zt, node);
1475 goto out;
1476 }
1477 /* Drop the TNC mutex prematurely and race with garbage collection */
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001478 zbr = znode->zbranch[n];
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001479 gc_seq1 = c->gc_seq;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001480 mutex_unlock(&c->tnc_mutex);
1481
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001482 if (ubifs_get_wbuf(c, zbr.lnum)) {
1483 /* We do not GC journal heads */
1484 err = ubifs_tnc_read_node(c, &zbr, node);
1485 return err;
1486 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001487
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001488 err = fallible_read_node(c, key, &zbr, node);
Adrian Hunter6dcfac42008-09-12 12:27:47 +03001489 if (err <= 0 || maybe_leb_gced(c, zbr.lnum, gc_seq1)) {
Adrian Hunter601c0bc2008-08-22 14:23:35 +03001490 /*
1491 * The node may have been GC'ed out from under us so try again
1492 * while keeping the TNC mutex locked.
1493 */
1494 safely = 1;
1495 goto again;
1496 }
1497 return 0;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001498
1499out:
1500 mutex_unlock(&c->tnc_mutex);
1501 return err;
1502}
1503
1504/**
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001505 * ubifs_tnc_get_bu_keys - lookup keys for bulk-read.
1506 * @c: UBIFS file-system description object
1507 * @bu: bulk-read parameters and results
1508 *
1509 * Lookup consecutive data node keys for the same inode that reside
Artem Bityutskiy6c0c42c2008-11-18 20:20:05 +02001510 * consecutively in the same LEB. This function returns zero in case of success
1511 * and a negative error code in case of failure.
1512 *
1513 * Note, if the bulk-read buffer length (@bu->buf_len) is known, this function
1514 * makes sure bulk-read nodes fit the buffer. Otherwise, this function prepares
Artem Bityutskiy6f7ab6d2009-01-27 16:12:31 +02001515 * maximum possible amount of nodes for bulk-read.
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001516 */
1517int ubifs_tnc_get_bu_keys(struct ubifs_info *c, struct bu_info *bu)
1518{
1519 int n, err = 0, lnum = -1, uninitialized_var(offs);
1520 int uninitialized_var(len);
1521 unsigned int block = key_block(c, &bu->key);
1522 struct ubifs_znode *znode;
1523
1524 bu->cnt = 0;
1525 bu->blk_cnt = 0;
1526 bu->eof = 0;
1527
1528 mutex_lock(&c->tnc_mutex);
1529 /* Find first key */
1530 err = ubifs_lookup_level0(c, &bu->key, &znode, &n);
1531 if (err < 0)
1532 goto out;
1533 if (err) {
1534 /* Key found */
1535 len = znode->zbranch[n].len;
1536 /* The buffer must be big enough for at least 1 node */
1537 if (len > bu->buf_len) {
1538 err = -EINVAL;
1539 goto out;
1540 }
1541 /* Add this key */
1542 bu->zbranch[bu->cnt++] = znode->zbranch[n];
1543 bu->blk_cnt += 1;
1544 lnum = znode->zbranch[n].lnum;
1545 offs = ALIGN(znode->zbranch[n].offs + len, 8);
1546 }
1547 while (1) {
1548 struct ubifs_zbranch *zbr;
1549 union ubifs_key *key;
1550 unsigned int next_block;
1551
1552 /* Find next key */
1553 err = tnc_next(c, &znode, &n);
1554 if (err)
1555 goto out;
1556 zbr = &znode->zbranch[n];
1557 key = &zbr->key;
1558 /* See if there is another data key for this file */
1559 if (key_inum(c, key) != key_inum(c, &bu->key) ||
1560 key_type(c, key) != UBIFS_DATA_KEY) {
1561 err = -ENOENT;
1562 goto out;
1563 }
1564 if (lnum < 0) {
1565 /* First key found */
1566 lnum = zbr->lnum;
1567 offs = ALIGN(zbr->offs + zbr->len, 8);
1568 len = zbr->len;
1569 if (len > bu->buf_len) {
1570 err = -EINVAL;
1571 goto out;
1572 }
1573 } else {
1574 /*
1575 * The data nodes must be in consecutive positions in
1576 * the same LEB.
1577 */
1578 if (zbr->lnum != lnum || zbr->offs != offs)
1579 goto out;
1580 offs += ALIGN(zbr->len, 8);
1581 len = ALIGN(len, 8) + zbr->len;
1582 /* Must not exceed buffer length */
1583 if (len > bu->buf_len)
1584 goto out;
1585 }
1586 /* Allow for holes */
1587 next_block = key_block(c, key);
1588 bu->blk_cnt += (next_block - block - 1);
1589 if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
1590 goto out;
1591 block = next_block;
1592 /* Add this key */
1593 bu->zbranch[bu->cnt++] = *zbr;
1594 bu->blk_cnt += 1;
1595 /* See if we have room for more */
1596 if (bu->cnt >= UBIFS_MAX_BULK_READ)
1597 goto out;
1598 if (bu->blk_cnt >= UBIFS_MAX_BULK_READ)
1599 goto out;
1600 }
1601out:
1602 if (err == -ENOENT) {
1603 bu->eof = 1;
1604 err = 0;
1605 }
1606 bu->gc_seq = c->gc_seq;
1607 mutex_unlock(&c->tnc_mutex);
1608 if (err)
1609 return err;
1610 /*
1611 * An enormous hole could cause bulk-read to encompass too many
1612 * page cache pages, so limit the number here.
1613 */
Adrian Hunter63c300b2008-09-17 12:11:13 +03001614 if (bu->blk_cnt > UBIFS_MAX_BULK_READ)
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001615 bu->blk_cnt = UBIFS_MAX_BULK_READ;
1616 /*
1617 * Ensure that bulk-read covers a whole number of page cache
1618 * pages.
1619 */
1620 if (UBIFS_BLOCKS_PER_PAGE == 1 ||
1621 !(bu->blk_cnt & (UBIFS_BLOCKS_PER_PAGE - 1)))
1622 return 0;
1623 if (bu->eof) {
1624 /* At the end of file we can round up */
1625 bu->blk_cnt += UBIFS_BLOCKS_PER_PAGE - 1;
1626 return 0;
1627 }
1628 /* Exclude data nodes that do not make up a whole page cache page */
1629 block = key_block(c, &bu->key) + bu->blk_cnt;
1630 block &= ~(UBIFS_BLOCKS_PER_PAGE - 1);
1631 while (bu->cnt) {
1632 if (key_block(c, &bu->zbranch[bu->cnt - 1].key) < block)
1633 break;
1634 bu->cnt -= 1;
1635 }
1636 return 0;
1637}
1638
1639/**
1640 * read_wbuf - bulk-read from a LEB with a wbuf.
1641 * @wbuf: wbuf that may overlap the read
1642 * @buf: buffer into which to read
1643 * @len: read length
1644 * @lnum: LEB number from which to read
1645 * @offs: offset from which to read
1646 *
1647 * This functions returns %0 on success or a negative error code on failure.
1648 */
1649static int read_wbuf(struct ubifs_wbuf *wbuf, void *buf, int len, int lnum,
1650 int offs)
1651{
1652 const struct ubifs_info *c = wbuf->c;
1653 int rlen, overlap;
1654
1655 dbg_io("LEB %d:%d, length %d", lnum, offs, len);
1656 ubifs_assert(wbuf && lnum >= 0 && lnum < c->leb_cnt && offs >= 0);
1657 ubifs_assert(!(offs & 7) && offs < c->leb_size);
1658 ubifs_assert(offs + len <= c->leb_size);
1659
1660 spin_lock(&wbuf->lock);
1661 overlap = (lnum == wbuf->lnum && offs + len > wbuf->offs);
1662 if (!overlap) {
1663 /* We may safely unlock the write-buffer and read the data */
1664 spin_unlock(&wbuf->lock);
1665 return ubi_read(c->ubi, lnum, buf, offs, len);
1666 }
1667
1668 /* Don't read under wbuf */
1669 rlen = wbuf->offs - offs;
1670 if (rlen < 0)
1671 rlen = 0;
1672
1673 /* Copy the rest from the write-buffer */
1674 memcpy(buf + rlen, wbuf->buf + offs + rlen - wbuf->offs, len - rlen);
1675 spin_unlock(&wbuf->lock);
1676
1677 if (rlen > 0)
1678 /* Read everything that goes before write-buffer */
1679 return ubi_read(c->ubi, lnum, buf, offs, rlen);
1680
1681 return 0;
1682}
1683
1684/**
1685 * validate_data_node - validate data nodes for bulk-read.
1686 * @c: UBIFS file-system description object
1687 * @buf: buffer containing data node to validate
1688 * @zbr: zbranch of data node to validate
1689 *
1690 * This functions returns %0 on success or a negative error code on failure.
1691 */
1692static int validate_data_node(struct ubifs_info *c, void *buf,
1693 struct ubifs_zbranch *zbr)
1694{
1695 union ubifs_key key1;
1696 struct ubifs_ch *ch = buf;
1697 int err, len;
1698
1699 if (ch->node_type != UBIFS_DATA_NODE) {
1700 ubifs_err("bad node type (%d but expected %d)",
1701 ch->node_type, UBIFS_DATA_NODE);
1702 goto out_err;
1703 }
1704
Adrian Hunter2953e732008-09-04 16:26:00 +03001705 err = ubifs_check_node(c, buf, zbr->lnum, zbr->offs, 0, 0);
Adrian Hunter4793e7c2008-09-02 16:29:46 +03001706 if (err) {
1707 ubifs_err("expected node type %d", UBIFS_DATA_NODE);
1708 goto out;
1709 }
1710
1711 len = le32_to_cpu(ch->len);
1712 if (len != zbr->len) {
1713 ubifs_err("bad node length %d, expected %d", len, zbr->len);
1714 goto out_err;
1715 }
1716
1717 /* Make sure the key of the read node is correct */
1718 key_read(c, buf + UBIFS_KEY_OFFSET, &key1);
1719 if (!keys_eq(c, &zbr->key, &key1)) {
1720 ubifs_err("bad key in node at LEB %d:%d",
1721 zbr->lnum, zbr->offs);
1722 dbg_tnc("looked for key %s found node's key %s",
1723 DBGKEY(&zbr->key), DBGKEY1(&key1));
1724 goto out_err;
1725 }
1726
1727 return 0;
1728
1729out_err:
1730 err = -EINVAL;
1731out:
1732 ubifs_err("bad node at LEB %d:%d", zbr->lnum, zbr->offs);
1733 dbg_dump_node(c, buf);
1734 dbg_dump_stack();
1735 return err;
1736}
1737
1738/**
1739 * ubifs_tnc_bulk_read - read a number of data nodes in one go.
1740 * @c: UBIFS file-system description object
1741 * @bu: bulk-read parameters and results
1742 *
1743 * This functions reads and validates the data nodes that were identified by the
1744 * 'ubifs_tnc_get_bu_keys()' function. This functions returns %0 on success,
1745 * -EAGAIN to indicate a race with GC, or another negative error code on
1746 * failure.
1747 */
1748int ubifs_tnc_bulk_read(struct ubifs_info *c, struct bu_info *bu)
1749{
1750 int lnum = bu->zbranch[0].lnum, offs = bu->zbranch[0].offs, len, err, i;
1751 struct ubifs_wbuf *wbuf;
1752 void *buf;
1753
1754 len = bu->zbranch[bu->cnt - 1].offs;
1755 len += bu->zbranch[bu->cnt - 1].len - offs;
1756 if (len > bu->buf_len) {
1757 ubifs_err("buffer too small %d vs %d", bu->buf_len, len);
1758 return -EINVAL;
1759 }
1760
1761 /* Do the read */
1762 wbuf = ubifs_get_wbuf(c, lnum);
1763 if (wbuf)
1764 err = read_wbuf(wbuf, bu->buf, len, lnum, offs);
1765 else
1766 err = ubi_read(c->ubi, lnum, bu->buf, offs, len);
1767
1768 /* Check for a race with GC */
1769 if (maybe_leb_gced(c, lnum, bu->gc_seq))
1770 return -EAGAIN;
1771
1772 if (err && err != -EBADMSG) {
1773 ubifs_err("failed to read from LEB %d:%d, error %d",
1774 lnum, offs, err);
1775 dbg_dump_stack();
1776 dbg_tnc("key %s", DBGKEY(&bu->key));
1777 return err;
1778 }
1779
1780 /* Validate the nodes read */
1781 buf = bu->buf;
1782 for (i = 0; i < bu->cnt; i++) {
1783 err = validate_data_node(c, buf, &bu->zbranch[i]);
1784 if (err)
1785 return err;
1786 buf = buf + ALIGN(bu->zbranch[i].len, 8);
1787 }
1788
1789 return 0;
1790}
1791
1792/**
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001793 * do_lookup_nm- look up a "hashed" node.
1794 * @c: UBIFS file-system description object
1795 * @key: node key to lookup
1796 * @node: the node is returned here
1797 * @nm: node name
1798 *
1799 * This function look up and reads a node which contains name hash in the key.
1800 * Since the hash may have collisions, there may be many nodes with the same
1801 * key, so we have to sequentially look to all of them until the needed one is
1802 * found. This function returns zero in case of success, %-ENOENT if the node
1803 * was not found, and a negative error code in case of failure.
1804 */
1805static int do_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1806 void *node, const struct qstr *nm)
1807{
1808 int found, n, err;
1809 struct ubifs_znode *znode;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001810
1811 dbg_tnc("name '%.*s' key %s", nm->len, nm->name, DBGKEY(key));
1812 mutex_lock(&c->tnc_mutex);
1813 found = ubifs_lookup_level0(c, key, &znode, &n);
1814 if (!found) {
1815 err = -ENOENT;
1816 goto out_unlock;
1817 } else if (found < 0) {
1818 err = found;
1819 goto out_unlock;
1820 }
1821
1822 ubifs_assert(n >= 0);
1823
1824 err = resolve_collision(c, key, &znode, &n, nm);
1825 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
1826 if (unlikely(err < 0))
1827 goto out_unlock;
1828 if (err == 0) {
1829 err = -ENOENT;
1830 goto out_unlock;
1831 }
1832
Adrian Hunter761e29f2008-08-20 16:32:40 +03001833 err = tnc_read_node_nm(c, &znode->zbranch[n], node);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001834
1835out_unlock:
1836 mutex_unlock(&c->tnc_mutex);
1837 return err;
1838}
1839
1840/**
1841 * ubifs_tnc_lookup_nm - look up a "hashed" node.
1842 * @c: UBIFS file-system description object
1843 * @key: node key to lookup
1844 * @node: the node is returned here
1845 * @nm: node name
1846 *
1847 * This function look up and reads a node which contains name hash in the key.
1848 * Since the hash may have collisions, there may be many nodes with the same
1849 * key, so we have to sequentially look to all of them until the needed one is
1850 * found. This function returns zero in case of success, %-ENOENT if the node
1851 * was not found, and a negative error code in case of failure.
1852 */
1853int ubifs_tnc_lookup_nm(struct ubifs_info *c, const union ubifs_key *key,
1854 void *node, const struct qstr *nm)
1855{
1856 int err, len;
1857 const struct ubifs_dent_node *dent = node;
1858
1859 /*
1860 * We assume that in most of the cases there are no name collisions and
1861 * 'ubifs_tnc_lookup()' returns us the right direntry.
1862 */
1863 err = ubifs_tnc_lookup(c, key, node);
1864 if (err)
1865 return err;
1866
1867 len = le16_to_cpu(dent->nlen);
1868 if (nm->len == len && !memcmp(dent->name, nm->name, len))
1869 return 0;
1870
1871 /*
1872 * Unluckily, there are hash collisions and we have to iterate over
1873 * them look at each direntry with colliding name hash sequentially.
1874 */
1875 return do_lookup_nm(c, key, node, nm);
1876}
1877
1878/**
1879 * correct_parent_keys - correct parent znodes' keys.
1880 * @c: UBIFS file-system description object
1881 * @znode: znode to correct parent znodes for
1882 *
1883 * This is a helper function for 'tnc_insert()'. When the key of the leftmost
1884 * zbranch changes, keys of parent znodes have to be corrected. This helper
1885 * function is called in such situations and corrects the keys if needed.
1886 */
1887static void correct_parent_keys(const struct ubifs_info *c,
1888 struct ubifs_znode *znode)
1889{
1890 union ubifs_key *key, *key1;
1891
1892 ubifs_assert(znode->parent);
1893 ubifs_assert(znode->iip == 0);
1894
1895 key = &znode->zbranch[0].key;
1896 key1 = &znode->parent->zbranch[0].key;
1897
1898 while (keys_cmp(c, key, key1) < 0) {
1899 key_copy(c, key, key1);
1900 znode = znode->parent;
1901 znode->alt = 1;
1902 if (!znode->parent || znode->iip)
1903 break;
1904 key1 = &znode->parent->zbranch[0].key;
1905 }
1906}
1907
1908/**
1909 * insert_zbranch - insert a zbranch into a znode.
1910 * @znode: znode into which to insert
1911 * @zbr: zbranch to insert
1912 * @n: slot number to insert to
1913 *
1914 * This is a helper function for 'tnc_insert()'. UBIFS does not allow "gaps" in
1915 * znode's array of zbranches and keeps zbranches consolidated, so when a new
1916 * zbranch has to be inserted to the @znode->zbranches[]' array at the @n-th
1917 * slot, zbranches starting from @n have to be moved right.
1918 */
1919static void insert_zbranch(struct ubifs_znode *znode,
1920 const struct ubifs_zbranch *zbr, int n)
1921{
1922 int i;
1923
1924 ubifs_assert(ubifs_zn_dirty(znode));
1925
1926 if (znode->level) {
1927 for (i = znode->child_cnt; i > n; i--) {
1928 znode->zbranch[i] = znode->zbranch[i - 1];
1929 if (znode->zbranch[i].znode)
1930 znode->zbranch[i].znode->iip = i;
1931 }
1932 if (zbr->znode)
1933 zbr->znode->iip = n;
1934 } else
1935 for (i = znode->child_cnt; i > n; i--)
1936 znode->zbranch[i] = znode->zbranch[i - 1];
1937
1938 znode->zbranch[n] = *zbr;
1939 znode->child_cnt += 1;
1940
1941 /*
1942 * After inserting at slot zero, the lower bound of the key range of
1943 * this znode may have changed. If this znode is subsequently split
1944 * then the upper bound of the key range may change, and furthermore
1945 * it could change to be lower than the original lower bound. If that
1946 * happens, then it will no longer be possible to find this znode in the
1947 * TNC using the key from the index node on flash. That is bad because
1948 * if it is not found, we will assume it is obsolete and may overwrite
1949 * it. Then if there is an unclean unmount, we will start using the
1950 * old index which will be broken.
1951 *
1952 * So we first mark znodes that have insertions at slot zero, and then
1953 * if they are split we add their lnum/offs to the old_idx tree.
1954 */
1955 if (n == 0)
1956 znode->alt = 1;
1957}
1958
1959/**
1960 * tnc_insert - insert a node into TNC.
1961 * @c: UBIFS file-system description object
1962 * @znode: znode to insert into
1963 * @zbr: branch to insert
1964 * @n: slot number to insert new zbranch to
1965 *
1966 * This function inserts a new node described by @zbr into znode @znode. If
1967 * znode does not have a free slot for new zbranch, it is split. Parent znodes
1968 * are splat as well if needed. Returns zero in case of success or a negative
1969 * error code in case of failure.
1970 */
1971static int tnc_insert(struct ubifs_info *c, struct ubifs_znode *znode,
1972 struct ubifs_zbranch *zbr, int n)
1973{
1974 struct ubifs_znode *zn, *zi, *zp;
1975 int i, keep, move, appending = 0;
Adrian Hunter2242c682008-09-05 11:56:05 +03001976 union ubifs_key *key = &zbr->key, *key1;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03001977
1978 ubifs_assert(n >= 0 && n <= c->fanout);
1979
1980 /* Implement naive insert for now */
1981again:
1982 zp = znode->parent;
1983 if (znode->child_cnt < c->fanout) {
1984 ubifs_assert(n != c->fanout);
1985 dbg_tnc("inserted at %d level %d, key %s", n, znode->level,
1986 DBGKEY(key));
1987
1988 insert_zbranch(znode, zbr, n);
1989
1990 /* Ensure parent's key is correct */
1991 if (n == 0 && zp && znode->iip == 0)
1992 correct_parent_keys(c, znode);
1993
1994 return 0;
1995 }
1996
1997 /*
1998 * Unfortunately, @znode does not have more empty slots and we have to
1999 * split it.
2000 */
2001 dbg_tnc("splitting level %d, key %s", znode->level, DBGKEY(key));
2002
2003 if (znode->alt)
2004 /*
2005 * We can no longer be sure of finding this znode by key, so we
2006 * record it in the old_idx tree.
2007 */
2008 ins_clr_old_idx_znode(c, znode);
2009
2010 zn = kzalloc(c->max_znode_sz, GFP_NOFS);
2011 if (!zn)
2012 return -ENOMEM;
2013 zn->parent = zp;
2014 zn->level = znode->level;
2015
2016 /* Decide where to split */
Adrian Hunter2242c682008-09-05 11:56:05 +03002017 if (znode->level == 0 && key_type(c, key) == UBIFS_DATA_KEY) {
2018 /* Try not to split consecutive data keys */
2019 if (n == c->fanout) {
2020 key1 = &znode->zbranch[n - 1].key;
2021 if (key_inum(c, key1) == key_inum(c, key) &&
2022 key_type(c, key1) == UBIFS_DATA_KEY)
2023 appending = 1;
2024 } else
2025 goto check_split;
2026 } else if (appending && n != c->fanout) {
2027 /* Try not to split consecutive data keys */
2028 appending = 0;
2029check_split:
2030 if (n >= (c->fanout + 1) / 2) {
2031 key1 = &znode->zbranch[0].key;
2032 if (key_inum(c, key1) == key_inum(c, key) &&
2033 key_type(c, key1) == UBIFS_DATA_KEY) {
2034 key1 = &znode->zbranch[n].key;
2035 if (key_inum(c, key1) != key_inum(c, key) ||
2036 key_type(c, key1) != UBIFS_DATA_KEY) {
2037 keep = n;
2038 move = c->fanout - keep;
2039 zi = znode;
2040 goto do_split;
2041 }
2042 }
2043 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002044 }
2045
2046 if (appending) {
2047 keep = c->fanout;
2048 move = 0;
2049 } else {
2050 keep = (c->fanout + 1) / 2;
2051 move = c->fanout - keep;
2052 }
2053
2054 /*
2055 * Although we don't at present, we could look at the neighbors and see
2056 * if we can move some zbranches there.
2057 */
2058
2059 if (n < keep) {
2060 /* Insert into existing znode */
2061 zi = znode;
2062 move += 1;
2063 keep -= 1;
2064 } else {
2065 /* Insert into new znode */
2066 zi = zn;
2067 n -= keep;
2068 /* Re-parent */
2069 if (zn->level != 0)
2070 zbr->znode->parent = zn;
2071 }
2072
Adrian Hunter2242c682008-09-05 11:56:05 +03002073do_split:
2074
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002075 __set_bit(DIRTY_ZNODE, &zn->flags);
2076 atomic_long_inc(&c->dirty_zn_cnt);
2077
2078 zn->child_cnt = move;
2079 znode->child_cnt = keep;
2080
2081 dbg_tnc("moving %d, keeping %d", move, keep);
2082
2083 /* Move zbranch */
2084 for (i = 0; i < move; i++) {
2085 zn->zbranch[i] = znode->zbranch[keep + i];
2086 /* Re-parent */
2087 if (zn->level != 0)
2088 if (zn->zbranch[i].znode) {
2089 zn->zbranch[i].znode->parent = zn;
2090 zn->zbranch[i].znode->iip = i;
2091 }
2092 }
2093
2094 /* Insert new key and branch */
2095 dbg_tnc("inserting at %d level %d, key %s", n, zn->level, DBGKEY(key));
2096
2097 insert_zbranch(zi, zbr, n);
2098
2099 /* Insert new znode (produced by spitting) into the parent */
2100 if (zp) {
Adrian Hunter2242c682008-09-05 11:56:05 +03002101 if (n == 0 && zi == znode && znode->iip == 0)
2102 correct_parent_keys(c, znode);
2103
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002104 /* Locate insertion point */
2105 n = znode->iip + 1;
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002106
2107 /* Tail recursion */
2108 zbr->key = zn->zbranch[0].key;
2109 zbr->znode = zn;
2110 zbr->lnum = 0;
2111 zbr->offs = 0;
2112 zbr->len = 0;
2113 znode = zp;
2114
2115 goto again;
2116 }
2117
2118 /* We have to split root znode */
2119 dbg_tnc("creating new zroot at level %d", znode->level + 1);
2120
2121 zi = kzalloc(c->max_znode_sz, GFP_NOFS);
2122 if (!zi)
2123 return -ENOMEM;
2124
2125 zi->child_cnt = 2;
2126 zi->level = znode->level + 1;
2127
2128 __set_bit(DIRTY_ZNODE, &zi->flags);
2129 atomic_long_inc(&c->dirty_zn_cnt);
2130
2131 zi->zbranch[0].key = znode->zbranch[0].key;
2132 zi->zbranch[0].znode = znode;
2133 zi->zbranch[0].lnum = c->zroot.lnum;
2134 zi->zbranch[0].offs = c->zroot.offs;
2135 zi->zbranch[0].len = c->zroot.len;
2136 zi->zbranch[1].key = zn->zbranch[0].key;
2137 zi->zbranch[1].znode = zn;
2138
2139 c->zroot.lnum = 0;
2140 c->zroot.offs = 0;
2141 c->zroot.len = 0;
2142 c->zroot.znode = zi;
2143
2144 zn->parent = zi;
2145 zn->iip = 1;
2146 znode->parent = zi;
2147 znode->iip = 0;
2148
2149 return 0;
2150}
2151
2152/**
2153 * ubifs_tnc_add - add a node to TNC.
2154 * @c: UBIFS file-system description object
2155 * @key: key to add
2156 * @lnum: LEB number of node
2157 * @offs: node offset
2158 * @len: node length
2159 *
2160 * This function adds a node with key @key to TNC. The node may be new or it may
2161 * obsolete some existing one. Returns %0 on success or negative error code on
2162 * failure.
2163 */
2164int ubifs_tnc_add(struct ubifs_info *c, const union ubifs_key *key, int lnum,
2165 int offs, int len)
2166{
2167 int found, n, err = 0;
2168 struct ubifs_znode *znode;
2169
2170 mutex_lock(&c->tnc_mutex);
2171 dbg_tnc("%d:%d, len %d, key %s", lnum, offs, len, DBGKEY(key));
2172 found = lookup_level0_dirty(c, key, &znode, &n);
2173 if (!found) {
2174 struct ubifs_zbranch zbr;
2175
2176 zbr.znode = NULL;
2177 zbr.lnum = lnum;
2178 zbr.offs = offs;
2179 zbr.len = len;
2180 key_copy(c, key, &zbr.key);
2181 err = tnc_insert(c, znode, &zbr, n + 1);
2182 } else if (found == 1) {
2183 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2184
2185 lnc_free(zbr);
2186 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2187 zbr->lnum = lnum;
2188 zbr->offs = offs;
2189 zbr->len = len;
2190 } else
2191 err = found;
2192 if (!err)
2193 err = dbg_check_tnc(c, 0);
2194 mutex_unlock(&c->tnc_mutex);
2195
2196 return err;
2197}
2198
2199/**
2200 * ubifs_tnc_replace - replace a node in the TNC only if the old node is found.
2201 * @c: UBIFS file-system description object
2202 * @key: key to add
2203 * @old_lnum: LEB number of old node
2204 * @old_offs: old node offset
2205 * @lnum: LEB number of node
2206 * @offs: node offset
2207 * @len: node length
2208 *
2209 * This function replaces a node with key @key in the TNC only if the old node
2210 * is found. This function is called by garbage collection when node are moved.
2211 * Returns %0 on success or negative error code on failure.
2212 */
2213int ubifs_tnc_replace(struct ubifs_info *c, const union ubifs_key *key,
2214 int old_lnum, int old_offs, int lnum, int offs, int len)
2215{
2216 int found, n, err = 0;
2217 struct ubifs_znode *znode;
2218
2219 mutex_lock(&c->tnc_mutex);
2220 dbg_tnc("old LEB %d:%d, new LEB %d:%d, len %d, key %s", old_lnum,
2221 old_offs, lnum, offs, len, DBGKEY(key));
2222 found = lookup_level0_dirty(c, key, &znode, &n);
2223 if (found < 0) {
2224 err = found;
2225 goto out_unlock;
2226 }
2227
2228 if (found == 1) {
2229 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2230
2231 found = 0;
2232 if (zbr->lnum == old_lnum && zbr->offs == old_offs) {
2233 lnc_free(zbr);
2234 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2235 if (err)
2236 goto out_unlock;
2237 zbr->lnum = lnum;
2238 zbr->offs = offs;
2239 zbr->len = len;
2240 found = 1;
2241 } else if (is_hash_key(c, key)) {
2242 found = resolve_collision_directly(c, key, &znode, &n,
2243 old_lnum, old_offs);
2244 dbg_tnc("rc returned %d, znode %p, n %d, LEB %d:%d",
2245 found, znode, n, old_lnum, old_offs);
2246 if (found < 0) {
2247 err = found;
2248 goto out_unlock;
2249 }
2250
2251 if (found) {
2252 /* Ensure the znode is dirtied */
2253 if (znode->cnext || !ubifs_zn_dirty(znode)) {
Artem Bityutskiyf92b9822008-12-28 11:34:26 +02002254 znode = dirty_cow_bottom_up(c, znode);
2255 if (IS_ERR(znode)) {
2256 err = PTR_ERR(znode);
2257 goto out_unlock;
2258 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002259 }
2260 zbr = &znode->zbranch[n];
2261 lnc_free(zbr);
2262 err = ubifs_add_dirt(c, zbr->lnum,
2263 zbr->len);
2264 if (err)
2265 goto out_unlock;
2266 zbr->lnum = lnum;
2267 zbr->offs = offs;
2268 zbr->len = len;
2269 }
2270 }
2271 }
2272
2273 if (!found)
2274 err = ubifs_add_dirt(c, lnum, len);
2275
2276 if (!err)
2277 err = dbg_check_tnc(c, 0);
2278
2279out_unlock:
2280 mutex_unlock(&c->tnc_mutex);
2281 return err;
2282}
2283
2284/**
2285 * ubifs_tnc_add_nm - add a "hashed" node to TNC.
2286 * @c: UBIFS file-system description object
2287 * @key: key to add
2288 * @lnum: LEB number of node
2289 * @offs: node offset
2290 * @len: node length
2291 * @nm: node name
2292 *
2293 * This is the same as 'ubifs_tnc_add()' but it should be used with keys which
2294 * may have collisions, like directory entry keys.
2295 */
2296int ubifs_tnc_add_nm(struct ubifs_info *c, const union ubifs_key *key,
2297 int lnum, int offs, int len, const struct qstr *nm)
2298{
2299 int found, n, err = 0;
2300 struct ubifs_znode *znode;
2301
2302 mutex_lock(&c->tnc_mutex);
2303 dbg_tnc("LEB %d:%d, name '%.*s', key %s", lnum, offs, nm->len, nm->name,
2304 DBGKEY(key));
2305 found = lookup_level0_dirty(c, key, &znode, &n);
2306 if (found < 0) {
2307 err = found;
2308 goto out_unlock;
2309 }
2310
2311 if (found == 1) {
2312 if (c->replaying)
2313 found = fallible_resolve_collision(c, key, &znode, &n,
2314 nm, 1);
2315 else
2316 found = resolve_collision(c, key, &znode, &n, nm);
2317 dbg_tnc("rc returned %d, znode %p, n %d", found, znode, n);
2318 if (found < 0) {
2319 err = found;
2320 goto out_unlock;
2321 }
2322
2323 /* Ensure the znode is dirtied */
2324 if (znode->cnext || !ubifs_zn_dirty(znode)) {
Artem Bityutskiyf92b9822008-12-28 11:34:26 +02002325 znode = dirty_cow_bottom_up(c, znode);
2326 if (IS_ERR(znode)) {
2327 err = PTR_ERR(znode);
2328 goto out_unlock;
2329 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002330 }
2331
2332 if (found == 1) {
2333 struct ubifs_zbranch *zbr = &znode->zbranch[n];
2334
2335 lnc_free(zbr);
2336 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2337 zbr->lnum = lnum;
2338 zbr->offs = offs;
2339 zbr->len = len;
2340 goto out_unlock;
2341 }
2342 }
2343
2344 if (!found) {
2345 struct ubifs_zbranch zbr;
2346
2347 zbr.znode = NULL;
2348 zbr.lnum = lnum;
2349 zbr.offs = offs;
2350 zbr.len = len;
2351 key_copy(c, key, &zbr.key);
2352 err = tnc_insert(c, znode, &zbr, n + 1);
2353 if (err)
2354 goto out_unlock;
2355 if (c->replaying) {
2356 /*
2357 * We did not find it in the index so there may be a
2358 * dangling branch still in the index. So we remove it
2359 * by passing 'ubifs_tnc_remove_nm()' the same key but
2360 * an unmatchable name.
2361 */
2362 struct qstr noname = { .len = 0, .name = "" };
2363
2364 err = dbg_check_tnc(c, 0);
2365 mutex_unlock(&c->tnc_mutex);
2366 if (err)
2367 return err;
2368 return ubifs_tnc_remove_nm(c, key, &noname);
2369 }
2370 }
2371
2372out_unlock:
2373 if (!err)
2374 err = dbg_check_tnc(c, 0);
2375 mutex_unlock(&c->tnc_mutex);
2376 return err;
2377}
2378
2379/**
2380 * tnc_delete - delete a znode form TNC.
2381 * @c: UBIFS file-system description object
2382 * @znode: znode to delete from
2383 * @n: zbranch slot number to delete
2384 *
2385 * This function deletes a leaf node from @n-th slot of @znode. Returns zero in
2386 * case of success and a negative error code in case of failure.
2387 */
2388static int tnc_delete(struct ubifs_info *c, struct ubifs_znode *znode, int n)
2389{
2390 struct ubifs_zbranch *zbr;
2391 struct ubifs_znode *zp;
2392 int i, err;
2393
2394 /* Delete without merge for now */
2395 ubifs_assert(znode->level == 0);
2396 ubifs_assert(n >= 0 && n < c->fanout);
2397 dbg_tnc("deleting %s", DBGKEY(&znode->zbranch[n].key));
2398
2399 zbr = &znode->zbranch[n];
2400 lnc_free(zbr);
2401
2402 err = ubifs_add_dirt(c, zbr->lnum, zbr->len);
2403 if (err) {
2404 dbg_dump_znode(c, znode);
2405 return err;
2406 }
2407
2408 /* We do not "gap" zbranch slots */
2409 for (i = n; i < znode->child_cnt - 1; i++)
2410 znode->zbranch[i] = znode->zbranch[i + 1];
2411 znode->child_cnt -= 1;
2412
2413 if (znode->child_cnt > 0)
2414 return 0;
2415
2416 /*
2417 * This was the last zbranch, we have to delete this znode from the
2418 * parent.
2419 */
2420
2421 do {
2422 ubifs_assert(!test_bit(OBSOLETE_ZNODE, &znode->flags));
2423 ubifs_assert(ubifs_zn_dirty(znode));
2424
2425 zp = znode->parent;
2426 n = znode->iip;
2427
2428 atomic_long_dec(&c->dirty_zn_cnt);
2429
2430 err = insert_old_idx_znode(c, znode);
2431 if (err)
2432 return err;
2433
2434 if (znode->cnext) {
2435 __set_bit(OBSOLETE_ZNODE, &znode->flags);
2436 atomic_long_inc(&c->clean_zn_cnt);
2437 atomic_long_inc(&ubifs_clean_zn_cnt);
2438 } else
2439 kfree(znode);
2440 znode = zp;
2441 } while (znode->child_cnt == 1); /* while removing last child */
2442
2443 /* Remove from znode, entry n - 1 */
2444 znode->child_cnt -= 1;
2445 ubifs_assert(znode->level != 0);
2446 for (i = n; i < znode->child_cnt; i++) {
2447 znode->zbranch[i] = znode->zbranch[i + 1];
2448 if (znode->zbranch[i].znode)
2449 znode->zbranch[i].znode->iip = i;
2450 }
2451
2452 /*
2453 * If this is the root and it has only 1 child then
2454 * collapse the tree.
2455 */
2456 if (!znode->parent) {
2457 while (znode->child_cnt == 1 && znode->level != 0) {
2458 zp = znode;
2459 zbr = &znode->zbranch[0];
2460 znode = get_znode(c, znode, 0);
2461 if (IS_ERR(znode))
2462 return PTR_ERR(znode);
2463 znode = dirty_cow_znode(c, zbr);
2464 if (IS_ERR(znode))
2465 return PTR_ERR(znode);
2466 znode->parent = NULL;
2467 znode->iip = 0;
2468 if (c->zroot.len) {
2469 err = insert_old_idx(c, c->zroot.lnum,
2470 c->zroot.offs);
2471 if (err)
2472 return err;
2473 }
2474 c->zroot.lnum = zbr->lnum;
2475 c->zroot.offs = zbr->offs;
2476 c->zroot.len = zbr->len;
2477 c->zroot.znode = znode;
2478 ubifs_assert(!test_bit(OBSOLETE_ZNODE,
2479 &zp->flags));
2480 ubifs_assert(test_bit(DIRTY_ZNODE, &zp->flags));
2481 atomic_long_dec(&c->dirty_zn_cnt);
2482
2483 if (zp->cnext) {
2484 __set_bit(OBSOLETE_ZNODE, &zp->flags);
2485 atomic_long_inc(&c->clean_zn_cnt);
2486 atomic_long_inc(&ubifs_clean_zn_cnt);
2487 } else
2488 kfree(zp);
2489 }
2490 }
2491
2492 return 0;
2493}
2494
2495/**
2496 * ubifs_tnc_remove - remove an index entry of a node.
2497 * @c: UBIFS file-system description object
2498 * @key: key of node
2499 *
2500 * Returns %0 on success or negative error code on failure.
2501 */
2502int ubifs_tnc_remove(struct ubifs_info *c, const union ubifs_key *key)
2503{
2504 int found, n, err = 0;
2505 struct ubifs_znode *znode;
2506
2507 mutex_lock(&c->tnc_mutex);
2508 dbg_tnc("key %s", DBGKEY(key));
2509 found = lookup_level0_dirty(c, key, &znode, &n);
2510 if (found < 0) {
2511 err = found;
2512 goto out_unlock;
2513 }
2514 if (found == 1)
2515 err = tnc_delete(c, znode, n);
2516 if (!err)
2517 err = dbg_check_tnc(c, 0);
2518
2519out_unlock:
2520 mutex_unlock(&c->tnc_mutex);
2521 return err;
2522}
2523
2524/**
2525 * ubifs_tnc_remove_nm - remove an index entry for a "hashed" node.
2526 * @c: UBIFS file-system description object
2527 * @key: key of node
2528 * @nm: directory entry name
2529 *
2530 * Returns %0 on success or negative error code on failure.
2531 */
2532int ubifs_tnc_remove_nm(struct ubifs_info *c, const union ubifs_key *key,
2533 const struct qstr *nm)
2534{
2535 int n, err;
2536 struct ubifs_znode *znode;
2537
2538 mutex_lock(&c->tnc_mutex);
2539 dbg_tnc("%.*s, key %s", nm->len, nm->name, DBGKEY(key));
2540 err = lookup_level0_dirty(c, key, &znode, &n);
2541 if (err < 0)
2542 goto out_unlock;
2543
2544 if (err) {
2545 if (c->replaying)
2546 err = fallible_resolve_collision(c, key, &znode, &n,
2547 nm, 0);
2548 else
2549 err = resolve_collision(c, key, &znode, &n, nm);
2550 dbg_tnc("rc returned %d, znode %p, n %d", err, znode, n);
2551 if (err < 0)
2552 goto out_unlock;
2553 if (err) {
2554 /* Ensure the znode is dirtied */
2555 if (znode->cnext || !ubifs_zn_dirty(znode)) {
2556 znode = dirty_cow_bottom_up(c, znode);
2557 if (IS_ERR(znode)) {
2558 err = PTR_ERR(znode);
2559 goto out_unlock;
2560 }
2561 }
2562 err = tnc_delete(c, znode, n);
2563 }
2564 }
2565
2566out_unlock:
2567 if (!err)
2568 err = dbg_check_tnc(c, 0);
2569 mutex_unlock(&c->tnc_mutex);
2570 return err;
2571}
2572
2573/**
2574 * key_in_range - determine if a key falls within a range of keys.
2575 * @c: UBIFS file-system description object
2576 * @key: key to check
2577 * @from_key: lowest key in range
2578 * @to_key: highest key in range
2579 *
2580 * This function returns %1 if the key is in range and %0 otherwise.
2581 */
2582static int key_in_range(struct ubifs_info *c, union ubifs_key *key,
2583 union ubifs_key *from_key, union ubifs_key *to_key)
2584{
2585 if (keys_cmp(c, key, from_key) < 0)
2586 return 0;
2587 if (keys_cmp(c, key, to_key) > 0)
2588 return 0;
2589 return 1;
2590}
2591
2592/**
2593 * ubifs_tnc_remove_range - remove index entries in range.
2594 * @c: UBIFS file-system description object
2595 * @from_key: lowest key to remove
2596 * @to_key: highest key to remove
2597 *
2598 * This function removes index entries starting at @from_key and ending at
2599 * @to_key. This function returns zero in case of success and a negative error
2600 * code in case of failure.
2601 */
2602int ubifs_tnc_remove_range(struct ubifs_info *c, union ubifs_key *from_key,
2603 union ubifs_key *to_key)
2604{
2605 int i, n, k, err = 0;
2606 struct ubifs_znode *znode;
2607 union ubifs_key *key;
2608
2609 mutex_lock(&c->tnc_mutex);
2610 while (1) {
2611 /* Find first level 0 znode that contains keys to remove */
2612 err = ubifs_lookup_level0(c, from_key, &znode, &n);
2613 if (err < 0)
2614 goto out_unlock;
2615
2616 if (err)
2617 key = from_key;
2618 else {
2619 err = tnc_next(c, &znode, &n);
2620 if (err == -ENOENT) {
2621 err = 0;
2622 goto out_unlock;
2623 }
2624 if (err < 0)
2625 goto out_unlock;
2626 key = &znode->zbranch[n].key;
2627 if (!key_in_range(c, key, from_key, to_key)) {
2628 err = 0;
2629 goto out_unlock;
2630 }
2631 }
2632
2633 /* Ensure the znode is dirtied */
2634 if (znode->cnext || !ubifs_zn_dirty(znode)) {
Artem Bityutskiyf92b9822008-12-28 11:34:26 +02002635 znode = dirty_cow_bottom_up(c, znode);
2636 if (IS_ERR(znode)) {
2637 err = PTR_ERR(znode);
2638 goto out_unlock;
2639 }
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002640 }
2641
2642 /* Remove all keys in range except the first */
2643 for (i = n + 1, k = 0; i < znode->child_cnt; i++, k++) {
2644 key = &znode->zbranch[i].key;
2645 if (!key_in_range(c, key, from_key, to_key))
2646 break;
2647 lnc_free(&znode->zbranch[i]);
2648 err = ubifs_add_dirt(c, znode->zbranch[i].lnum,
2649 znode->zbranch[i].len);
2650 if (err) {
2651 dbg_dump_znode(c, znode);
2652 goto out_unlock;
2653 }
2654 dbg_tnc("removing %s", DBGKEY(key));
2655 }
2656 if (k) {
2657 for (i = n + 1 + k; i < znode->child_cnt; i++)
2658 znode->zbranch[i - k] = znode->zbranch[i];
2659 znode->child_cnt -= k;
2660 }
2661
2662 /* Now delete the first */
2663 err = tnc_delete(c, znode, n);
2664 if (err)
2665 goto out_unlock;
2666 }
2667
2668out_unlock:
2669 if (!err)
2670 err = dbg_check_tnc(c, 0);
2671 mutex_unlock(&c->tnc_mutex);
2672 return err;
2673}
2674
2675/**
2676 * ubifs_tnc_remove_ino - remove an inode from TNC.
2677 * @c: UBIFS file-system description object
2678 * @inum: inode number to remove
2679 *
2680 * This function remove inode @inum and all the extended attributes associated
2681 * with the anode from TNC and returns zero in case of success or a negative
2682 * error code in case of failure.
2683 */
2684int ubifs_tnc_remove_ino(struct ubifs_info *c, ino_t inum)
2685{
2686 union ubifs_key key1, key2;
2687 struct ubifs_dent_node *xent, *pxent = NULL;
2688 struct qstr nm = { .name = NULL };
2689
Artem Bityutskiye84461a2008-10-29 12:08:43 +02002690 dbg_tnc("ino %lu", (unsigned long)inum);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002691
2692 /*
2693 * Walk all extended attribute entries and remove them together with
2694 * corresponding extended attribute inodes.
2695 */
2696 lowest_xent_key(c, &key1, inum);
2697 while (1) {
2698 ino_t xattr_inum;
2699 int err;
2700
2701 xent = ubifs_tnc_next_ent(c, &key1, &nm);
2702 if (IS_ERR(xent)) {
2703 err = PTR_ERR(xent);
2704 if (err == -ENOENT)
2705 break;
2706 return err;
2707 }
2708
2709 xattr_inum = le64_to_cpu(xent->inum);
Artem Bityutskiye84461a2008-10-29 12:08:43 +02002710 dbg_tnc("xent '%s', ino %lu", xent->name,
2711 (unsigned long)xattr_inum);
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002712
2713 nm.name = xent->name;
2714 nm.len = le16_to_cpu(xent->nlen);
2715 err = ubifs_tnc_remove_nm(c, &key1, &nm);
2716 if (err) {
2717 kfree(xent);
2718 return err;
2719 }
2720
2721 lowest_ino_key(c, &key1, xattr_inum);
2722 highest_ino_key(c, &key2, xattr_inum);
2723 err = ubifs_tnc_remove_range(c, &key1, &key2);
2724 if (err) {
2725 kfree(xent);
2726 return err;
2727 }
2728
2729 kfree(pxent);
2730 pxent = xent;
2731 key_read(c, &xent->key, &key1);
2732 }
2733
2734 kfree(pxent);
2735 lowest_ino_key(c, &key1, inum);
2736 highest_ino_key(c, &key2, inum);
2737
2738 return ubifs_tnc_remove_range(c, &key1, &key2);
2739}
2740
2741/**
2742 * ubifs_tnc_next_ent - walk directory or extended attribute entries.
2743 * @c: UBIFS file-system description object
2744 * @key: key of last entry
2745 * @nm: name of last entry found or %NULL
2746 *
2747 * This function finds and reads the next directory or extended attribute entry
2748 * after the given key (@key) if there is one. @nm is used to resolve
2749 * collisions.
2750 *
2751 * If the name of the current entry is not known and only the key is known,
2752 * @nm->name has to be %NULL. In this case the semantics of this function is a
2753 * little bit different and it returns the entry corresponding to this key, not
2754 * the next one. If the key was not found, the closest "right" entry is
2755 * returned.
2756 *
2757 * If the fist entry has to be found, @key has to contain the lowest possible
2758 * key value for this inode and @name has to be %NULL.
2759 *
2760 * This function returns the found directory or extended attribute entry node
2761 * in case of success, %-ENOENT is returned if no entry was found, and a
2762 * negative error code is returned in case of failure.
2763 */
2764struct ubifs_dent_node *ubifs_tnc_next_ent(struct ubifs_info *c,
2765 union ubifs_key *key,
2766 const struct qstr *nm)
2767{
2768 int n, err, type = key_type(c, key);
2769 struct ubifs_znode *znode;
2770 struct ubifs_dent_node *dent;
2771 struct ubifs_zbranch *zbr;
2772 union ubifs_key *dkey;
2773
2774 dbg_tnc("%s %s", nm->name ? (char *)nm->name : "(lowest)", DBGKEY(key));
2775 ubifs_assert(is_hash_key(c, key));
2776
2777 mutex_lock(&c->tnc_mutex);
2778 err = ubifs_lookup_level0(c, key, &znode, &n);
2779 if (unlikely(err < 0))
2780 goto out_unlock;
2781
2782 if (nm->name) {
2783 if (err) {
2784 /* Handle collisions */
2785 err = resolve_collision(c, key, &znode, &n, nm);
2786 dbg_tnc("rc returned %d, znode %p, n %d",
2787 err, znode, n);
2788 if (unlikely(err < 0))
2789 goto out_unlock;
2790 }
2791
2792 /* Now find next entry */
2793 err = tnc_next(c, &znode, &n);
2794 if (unlikely(err))
2795 goto out_unlock;
2796 } else {
2797 /*
2798 * The full name of the entry was not given, in which case the
2799 * behavior of this function is a little different and it
2800 * returns current entry, not the next one.
2801 */
2802 if (!err) {
2803 /*
2804 * However, the given key does not exist in the TNC
2805 * tree and @znode/@n variables contain the closest
2806 * "preceding" element. Switch to the next one.
2807 */
2808 err = tnc_next(c, &znode, &n);
2809 if (err)
2810 goto out_unlock;
2811 }
2812 }
2813
2814 zbr = &znode->zbranch[n];
2815 dent = kmalloc(zbr->len, GFP_NOFS);
2816 if (unlikely(!dent)) {
2817 err = -ENOMEM;
2818 goto out_unlock;
2819 }
2820
2821 /*
2822 * The above 'tnc_next()' call could lead us to the next inode, check
2823 * this.
2824 */
2825 dkey = &zbr->key;
2826 if (key_inum(c, dkey) != key_inum(c, key) ||
2827 key_type(c, dkey) != type) {
2828 err = -ENOENT;
2829 goto out_free;
2830 }
2831
2832 err = tnc_read_node_nm(c, zbr, dent);
2833 if (unlikely(err))
2834 goto out_free;
2835
2836 mutex_unlock(&c->tnc_mutex);
2837 return dent;
2838
2839out_free:
2840 kfree(dent);
2841out_unlock:
2842 mutex_unlock(&c->tnc_mutex);
2843 return ERR_PTR(err);
2844}
2845
2846/**
2847 * tnc_destroy_cnext - destroy left-over obsolete znodes from a failed commit.
2848 * @c: UBIFS file-system description object
2849 *
2850 * Destroy left-over obsolete znodes from a failed commit.
2851 */
2852static void tnc_destroy_cnext(struct ubifs_info *c)
2853{
2854 struct ubifs_znode *cnext;
2855
2856 if (!c->cnext)
2857 return;
2858 ubifs_assert(c->cmt_state == COMMIT_BROKEN);
2859 cnext = c->cnext;
2860 do {
2861 struct ubifs_znode *znode = cnext;
2862
2863 cnext = cnext->cnext;
2864 if (test_bit(OBSOLETE_ZNODE, &znode->flags))
2865 kfree(znode);
2866 } while (cnext && cnext != c->cnext);
2867}
2868
2869/**
2870 * ubifs_tnc_close - close TNC subsystem and free all related resources.
2871 * @c: UBIFS file-system description object
2872 */
2873void ubifs_tnc_close(struct ubifs_info *c)
2874{
2875 long clean_freed;
2876
2877 tnc_destroy_cnext(c);
2878 if (c->zroot.znode) {
2879 clean_freed = ubifs_destroy_tnc_subtree(c->zroot.znode);
2880 atomic_long_sub(clean_freed, &ubifs_clean_zn_cnt);
2881 }
2882 kfree(c->gap_lebs);
2883 kfree(c->ilebs);
2884 destroy_old_idx(c);
2885}
2886
2887/**
2888 * left_znode - get the znode to the left.
2889 * @c: UBIFS file-system description object
2890 * @znode: znode
2891 *
2892 * This function returns a pointer to the znode to the left of @znode or NULL if
2893 * there is not one. A negative error code is returned on failure.
2894 */
2895static struct ubifs_znode *left_znode(struct ubifs_info *c,
2896 struct ubifs_znode *znode)
2897{
2898 int level = znode->level;
2899
2900 while (1) {
2901 int n = znode->iip - 1;
2902
2903 /* Go up until we can go left */
2904 znode = znode->parent;
2905 if (!znode)
2906 return NULL;
2907 if (n >= 0) {
2908 /* Now go down the rightmost branch to 'level' */
2909 znode = get_znode(c, znode, n);
2910 if (IS_ERR(znode))
2911 return znode;
2912 while (znode->level != level) {
2913 n = znode->child_cnt - 1;
2914 znode = get_znode(c, znode, n);
2915 if (IS_ERR(znode))
2916 return znode;
2917 }
2918 break;
2919 }
2920 }
2921 return znode;
2922}
2923
2924/**
2925 * right_znode - get the znode to the right.
2926 * @c: UBIFS file-system description object
2927 * @znode: znode
2928 *
2929 * This function returns a pointer to the znode to the right of @znode or NULL
2930 * if there is not one. A negative error code is returned on failure.
2931 */
2932static struct ubifs_znode *right_znode(struct ubifs_info *c,
2933 struct ubifs_znode *znode)
2934{
2935 int level = znode->level;
2936
2937 while (1) {
2938 int n = znode->iip + 1;
2939
2940 /* Go up until we can go right */
2941 znode = znode->parent;
2942 if (!znode)
2943 return NULL;
2944 if (n < znode->child_cnt) {
2945 /* Now go down the leftmost branch to 'level' */
2946 znode = get_znode(c, znode, n);
2947 if (IS_ERR(znode))
2948 return znode;
2949 while (znode->level != level) {
2950 znode = get_znode(c, znode, 0);
2951 if (IS_ERR(znode))
2952 return znode;
2953 }
2954 break;
2955 }
2956 }
2957 return znode;
2958}
2959
2960/**
2961 * lookup_znode - find a particular indexing node from TNC.
2962 * @c: UBIFS file-system description object
2963 * @key: index node key to lookup
2964 * @level: index node level
2965 * @lnum: index node LEB number
2966 * @offs: index node offset
2967 *
2968 * This function searches an indexing node by its first key @key and its
2969 * address @lnum:@offs. It looks up the indexing tree by pulling all indexing
Artem Bityutskiyba2f48f2010-08-22 07:10:12 +03002970 * nodes it traverses to TNC. This function is called for indexing nodes which
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002971 * were found on the media by scanning, for example when garbage-collecting or
2972 * when doing in-the-gaps commit. This means that the indexing node which is
2973 * looked for does not have to have exactly the same leftmost key @key, because
2974 * the leftmost key may have been changed, in which case TNC will contain a
2975 * dirty znode which still refers the same @lnum:@offs. This function is clever
2976 * enough to recognize such indexing nodes.
2977 *
2978 * Note, if a znode was deleted or changed too much, then this function will
2979 * not find it. For situations like this UBIFS has the old index RB-tree
2980 * (indexed by @lnum:@offs).
2981 *
2982 * This function returns a pointer to the znode found or %NULL if it is not
2983 * found. A negative error code is returned on failure.
2984 */
2985static struct ubifs_znode *lookup_znode(struct ubifs_info *c,
2986 union ubifs_key *key, int level,
2987 int lnum, int offs)
2988{
2989 struct ubifs_znode *znode, *zn;
2990 int n, nn;
2991
Artem Bityutskiyba2f48f2010-08-22 07:10:12 +03002992 ubifs_assert(key_type(c, key) < UBIFS_INVALID_KEY);
2993
Artem Bityutskiy1e517642008-07-14 19:08:37 +03002994 /*
2995 * The arguments have probably been read off flash, so don't assume
2996 * they are valid.
2997 */
2998 if (level < 0)
2999 return ERR_PTR(-EINVAL);
3000
3001 /* Get the root znode */
3002 znode = c->zroot.znode;
3003 if (!znode) {
3004 znode = ubifs_load_znode(c, &c->zroot, NULL, 0);
3005 if (IS_ERR(znode))
3006 return znode;
3007 }
3008 /* Check if it is the one we are looking for */
3009 if (c->zroot.lnum == lnum && c->zroot.offs == offs)
3010 return znode;
3011 /* Descend to the parent level i.e. (level + 1) */
3012 if (level >= znode->level)
3013 return NULL;
3014 while (1) {
3015 ubifs_search_zbranch(c, znode, key, &n);
3016 if (n < 0) {
3017 /*
3018 * We reached a znode where the leftmost key is greater
3019 * than the key we are searching for. This is the same
3020 * situation as the one described in a huge comment at
3021 * the end of the 'ubifs_lookup_level0()' function. And
3022 * for exactly the same reasons we have to try to look
3023 * left before giving up.
3024 */
3025 znode = left_znode(c, znode);
3026 if (!znode)
3027 return NULL;
3028 if (IS_ERR(znode))
3029 return znode;
3030 ubifs_search_zbranch(c, znode, key, &n);
3031 ubifs_assert(n >= 0);
3032 }
3033 if (znode->level == level + 1)
3034 break;
3035 znode = get_znode(c, znode, n);
3036 if (IS_ERR(znode))
3037 return znode;
3038 }
3039 /* Check if the child is the one we are looking for */
3040 if (znode->zbranch[n].lnum == lnum && znode->zbranch[n].offs == offs)
3041 return get_znode(c, znode, n);
3042 /* If the key is unique, there is nowhere else to look */
3043 if (!is_hash_key(c, key))
3044 return NULL;
3045 /*
3046 * The key is not unique and so may be also in the znodes to either
3047 * side.
3048 */
3049 zn = znode;
3050 nn = n;
3051 /* Look left */
3052 while (1) {
3053 /* Move one branch to the left */
3054 if (n)
3055 n -= 1;
3056 else {
3057 znode = left_znode(c, znode);
3058 if (!znode)
3059 break;
3060 if (IS_ERR(znode))
3061 return znode;
3062 n = znode->child_cnt - 1;
3063 }
3064 /* Check it */
3065 if (znode->zbranch[n].lnum == lnum &&
3066 znode->zbranch[n].offs == offs)
3067 return get_znode(c, znode, n);
3068 /* Stop if the key is less than the one we are looking for */
3069 if (keys_cmp(c, &znode->zbranch[n].key, key) < 0)
3070 break;
3071 }
3072 /* Back to the middle */
3073 znode = zn;
3074 n = nn;
3075 /* Look right */
3076 while (1) {
3077 /* Move one branch to the right */
3078 if (++n >= znode->child_cnt) {
3079 znode = right_znode(c, znode);
3080 if (!znode)
3081 break;
3082 if (IS_ERR(znode))
3083 return znode;
3084 n = 0;
3085 }
3086 /* Check it */
3087 if (znode->zbranch[n].lnum == lnum &&
3088 znode->zbranch[n].offs == offs)
3089 return get_znode(c, znode, n);
3090 /* Stop if the key is greater than the one we are looking for */
3091 if (keys_cmp(c, &znode->zbranch[n].key, key) > 0)
3092 break;
3093 }
3094 return NULL;
3095}
3096
3097/**
3098 * is_idx_node_in_tnc - determine if an index node is in the TNC.
3099 * @c: UBIFS file-system description object
3100 * @key: key of index node
3101 * @level: index node level
3102 * @lnum: LEB number of index node
3103 * @offs: offset of index node
3104 *
3105 * This function returns %0 if the index node is not referred to in the TNC, %1
3106 * if the index node is referred to in the TNC and the corresponding znode is
3107 * dirty, %2 if an index node is referred to in the TNC and the corresponding
3108 * znode is clean, and a negative error code in case of failure.
3109 *
3110 * Note, the @key argument has to be the key of the first child. Also note,
3111 * this function relies on the fact that 0:0 is never a valid LEB number and
3112 * offset for a main-area node.
3113 */
3114int is_idx_node_in_tnc(struct ubifs_info *c, union ubifs_key *key, int level,
3115 int lnum, int offs)
3116{
3117 struct ubifs_znode *znode;
3118
3119 znode = lookup_znode(c, key, level, lnum, offs);
3120 if (!znode)
3121 return 0;
3122 if (IS_ERR(znode))
3123 return PTR_ERR(znode);
3124
3125 return ubifs_zn_dirty(znode) ? 1 : 2;
3126}
3127
3128/**
3129 * is_leaf_node_in_tnc - determine if a non-indexing not is in the TNC.
3130 * @c: UBIFS file-system description object
3131 * @key: node key
3132 * @lnum: node LEB number
3133 * @offs: node offset
3134 *
3135 * This function returns %1 if the node is referred to in the TNC, %0 if it is
3136 * not, and a negative error code in case of failure.
3137 *
3138 * Note, this function relies on the fact that 0:0 is never a valid LEB number
3139 * and offset for a main-area node.
3140 */
3141static int is_leaf_node_in_tnc(struct ubifs_info *c, union ubifs_key *key,
3142 int lnum, int offs)
3143{
3144 struct ubifs_zbranch *zbr;
3145 struct ubifs_znode *znode, *zn;
3146 int n, found, err, nn;
3147 const int unique = !is_hash_key(c, key);
3148
3149 found = ubifs_lookup_level0(c, key, &znode, &n);
3150 if (found < 0)
3151 return found; /* Error code */
3152 if (!found)
3153 return 0;
3154 zbr = &znode->zbranch[n];
3155 if (lnum == zbr->lnum && offs == zbr->offs)
3156 return 1; /* Found it */
3157 if (unique)
3158 return 0;
3159 /*
3160 * Because the key is not unique, we have to look left
3161 * and right as well
3162 */
3163 zn = znode;
3164 nn = n;
3165 /* Look left */
3166 while (1) {
3167 err = tnc_prev(c, &znode, &n);
3168 if (err == -ENOENT)
3169 break;
3170 if (err)
3171 return err;
3172 if (keys_cmp(c, key, &znode->zbranch[n].key))
3173 break;
3174 zbr = &znode->zbranch[n];
3175 if (lnum == zbr->lnum && offs == zbr->offs)
3176 return 1; /* Found it */
3177 }
3178 /* Look right */
3179 znode = zn;
3180 n = nn;
3181 while (1) {
3182 err = tnc_next(c, &znode, &n);
3183 if (err) {
3184 if (err == -ENOENT)
3185 return 0;
3186 return err;
3187 }
3188 if (keys_cmp(c, key, &znode->zbranch[n].key))
3189 break;
3190 zbr = &znode->zbranch[n];
3191 if (lnum == zbr->lnum && offs == zbr->offs)
3192 return 1; /* Found it */
3193 }
3194 return 0;
3195}
3196
3197/**
3198 * ubifs_tnc_has_node - determine whether a node is in the TNC.
3199 * @c: UBIFS file-system description object
3200 * @key: node key
3201 * @level: index node level (if it is an index node)
3202 * @lnum: node LEB number
3203 * @offs: node offset
3204 * @is_idx: non-zero if the node is an index node
3205 *
3206 * This function returns %1 if the node is in the TNC, %0 if it is not, and a
3207 * negative error code in case of failure. For index nodes, @key has to be the
3208 * key of the first child. An index node is considered to be in the TNC only if
3209 * the corresponding znode is clean or has not been loaded.
3210 */
3211int ubifs_tnc_has_node(struct ubifs_info *c, union ubifs_key *key, int level,
3212 int lnum, int offs, int is_idx)
3213{
3214 int err;
3215
3216 mutex_lock(&c->tnc_mutex);
3217 if (is_idx) {
3218 err = is_idx_node_in_tnc(c, key, level, lnum, offs);
3219 if (err < 0)
3220 goto out_unlock;
3221 if (err == 1)
3222 /* The index node was found but it was dirty */
3223 err = 0;
3224 else if (err == 2)
3225 /* The index node was found and it was clean */
3226 err = 1;
3227 else
3228 BUG_ON(err != 0);
3229 } else
3230 err = is_leaf_node_in_tnc(c, key, lnum, offs);
3231
3232out_unlock:
3233 mutex_unlock(&c->tnc_mutex);
3234 return err;
3235}
3236
3237/**
3238 * ubifs_dirty_idx_node - dirty an index node.
3239 * @c: UBIFS file-system description object
3240 * @key: index node key
3241 * @level: index node level
3242 * @lnum: index node LEB number
3243 * @offs: index node offset
3244 *
3245 * This function loads and dirties an index node so that it can be garbage
3246 * collected. The @key argument has to be the key of the first child. This
3247 * function relies on the fact that 0:0 is never a valid LEB number and offset
3248 * for a main-area node. Returns %0 on success and a negative error code on
3249 * failure.
3250 */
3251int ubifs_dirty_idx_node(struct ubifs_info *c, union ubifs_key *key, int level,
3252 int lnum, int offs)
3253{
3254 struct ubifs_znode *znode;
3255 int err = 0;
3256
3257 mutex_lock(&c->tnc_mutex);
3258 znode = lookup_znode(c, key, level, lnum, offs);
3259 if (!znode)
3260 goto out_unlock;
3261 if (IS_ERR(znode)) {
3262 err = PTR_ERR(znode);
3263 goto out_unlock;
3264 }
3265 znode = dirty_cow_bottom_up(c, znode);
3266 if (IS_ERR(znode)) {
3267 err = PTR_ERR(znode);
3268 goto out_unlock;
3269 }
3270
3271out_unlock:
3272 mutex_unlock(&c->tnc_mutex);
3273 return err;
3274}
Artem Bityutskiye3c3efc2009-08-27 16:34:19 +03003275
3276#ifdef CONFIG_UBIFS_FS_DEBUG
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 (!(ubifs_chk_flags & UBIFS_CHK_GEN))
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 "(data key %s)", (unsigned long)inode->i_ino, size,
3334 ((loff_t)block) << UBIFS_BLOCK_SHIFT, DBGKEY(key));
3335 dbg_dump_inode(c, inode);
3336 dbg_dump_stack();
3337 err = -EINVAL;
3338
3339out_unlock:
3340 mutex_unlock(&c->tnc_mutex);
3341 return err;
3342}
3343
3344#endif /* CONFIG_UBIFS_FS_DEBUG */