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1 /*
2 * This file is part of UBIFS.
3 *
4 * Copyright (C) 2006-2008 Nokia Corporation
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License along with
16 * this program; if not, write to the Free Software Foundation, Inc., 51
17 * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 * Authors: Adrian Hunter
20 * Artem Bityutskiy (Битюцкий Артём)
21 */
22
23 /*
24 * This file implements functions needed to recover from unclean un-mounts.
25 * When UBIFS is mounted, it checks a flag on the master node to determine if
26 * an un-mount was completed successfully. If not, the process of mounting
27 * incorporates additional checking and fixing of on-flash data structures.
28 * UBIFS always cleans away all remnants of an unclean un-mount, so that
29 * errors do not accumulate. However UBIFS defers recovery if it is mounted
30 * read-only, and the flash is not modified in that case.
31 *
32 * The general UBIFS approach to the recovery is that it recovers from
33 * corruptions which could be caused by power cuts, but it refuses to recover
34 * from corruption caused by other reasons. And UBIFS tries to distinguish
35 * between these 2 reasons of corruptions and silently recover in the former
36 * case and loudly complain in the latter case.
37 *
38 * UBIFS writes only to erased LEBs, so it writes only to the flash space
39 * containing only 0xFFs. UBIFS also always writes strictly from the beginning
40 * of the LEB to the end. And UBIFS assumes that the underlying flash media
41 * writes in @c->max_write_size bytes at a time.
42 *
43 * Hence, if UBIFS finds a corrupted node at offset X, it expects only the min.
44 * I/O unit corresponding to offset X to contain corrupted data, all the
45 * following min. I/O units have to contain empty space (all 0xFFs). If this is
46 * not true, the corruption cannot be the result of a power cut, and UBIFS
47 * refuses to mount.
48 */
49
50 #include <linux/crc32.h>
51 #include <linux/slab.h>
52 #include "ubifs.h"
53
54 /**
55 * is_empty - determine whether a buffer is empty (contains all 0xff).
56 * @buf: buffer to clean
57 * @len: length of buffer
58 *
59 * This function returns %1 if the buffer is empty (contains all 0xff) otherwise
60 * %0 is returned.
61 */
62 static int is_empty(void *buf, int len)
63 {
64 uint8_t *p = buf;
65 int i;
66
67 for (i = 0; i < len; i++)
68 if (*p++ != 0xff)
69 return 0;
70 return 1;
71 }
72
73 /**
74 * first_non_ff - find offset of the first non-0xff byte.
75 * @buf: buffer to search in
76 * @len: length of buffer
77 *
78 * This function returns offset of the first non-0xff byte in @buf or %-1 if
79 * the buffer contains only 0xff bytes.
80 */
81 static int first_non_ff(void *buf, int len)
82 {
83 uint8_t *p = buf;
84 int i;
85
86 for (i = 0; i < len; i++)
87 if (*p++ != 0xff)
88 return i;
89 return -1;
90 }
91
92 /**
93 * get_master_node - get the last valid master node allowing for corruption.
94 * @c: UBIFS file-system description object
95 * @lnum: LEB number
96 * @pbuf: buffer containing the LEB read, is returned here
97 * @mst: master node, if found, is returned here
98 * @cor: corruption, if found, is returned here
99 *
100 * This function allocates a buffer, reads the LEB into it, and finds and
101 * returns the last valid master node allowing for one area of corruption.
102 * The corrupt area, if there is one, must be consistent with the assumption
103 * that it is the result of an unclean unmount while the master node was being
104 * written. Under those circumstances, it is valid to use the previously written
105 * master node.
106 *
107 * This function returns %0 on success and a negative error code on failure.
108 */
109 static int get_master_node(const struct ubifs_info *c, int lnum, void **pbuf,
110 struct ubifs_mst_node **mst, void **cor)
111 {
112 const int sz = c->mst_node_alsz;
113 int err, offs, len;
114 void *sbuf, *buf;
115
116 sbuf = vmalloc(c->leb_size);
117 if (!sbuf)
118 return -ENOMEM;
119
120 err = ubifs_leb_read(c, lnum, sbuf, 0, c->leb_size, 0);
121 if (err && err != -EBADMSG)
122 goto out_free;
123
124 /* Find the first position that is definitely not a node */
125 offs = 0;
126 buf = sbuf;
127 len = c->leb_size;
128 while (offs + UBIFS_MST_NODE_SZ <= c->leb_size) {
129 struct ubifs_ch *ch = buf;
130
131 if (le32_to_cpu(ch->magic) != UBIFS_NODE_MAGIC)
132 break;
133 offs += sz;
134 buf += sz;
135 len -= sz;
136 }
137 /* See if there was a valid master node before that */
138 if (offs) {
139 int ret;
140
141 offs -= sz;
142 buf -= sz;
143 len += sz;
144 ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1);
145 if (ret != SCANNED_A_NODE && offs) {
146 /* Could have been corruption so check one place back */
147 offs -= sz;
148 buf -= sz;
149 len += sz;
150 ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1);
151 if (ret != SCANNED_A_NODE)
152 /*
153 * We accept only one area of corruption because
154 * we are assuming that it was caused while
155 * trying to write a master node.
156 */
157 goto out_err;
158 }
159 if (ret == SCANNED_A_NODE) {
160 struct ubifs_ch *ch = buf;
161
162 if (ch->node_type != UBIFS_MST_NODE)
163 goto out_err;
164 dbg_rcvry("found a master node at %d:%d", lnum, offs);
165 *mst = buf;
166 offs += sz;
167 buf += sz;
168 len -= sz;
169 }
170 }
171 /* Check for corruption */
172 if (offs < c->leb_size) {
173 if (!is_empty(buf, min_t(int, len, sz))) {
174 *cor = buf;
175 dbg_rcvry("found corruption at %d:%d", lnum, offs);
176 }
177 offs += sz;
178 buf += sz;
179 len -= sz;
180 }
181 /* Check remaining empty space */
182 if (offs < c->leb_size)
183 if (!is_empty(buf, len))
184 goto out_err;
185 *pbuf = sbuf;
186 return 0;
187
188 out_err:
189 err = -EINVAL;
190 out_free:
191 vfree(sbuf);
192 *mst = NULL;
193 *cor = NULL;
194 return err;
195 }
196
197 /**
198 * write_rcvrd_mst_node - write recovered master node.
199 * @c: UBIFS file-system description object
200 * @mst: master node
201 *
202 * This function returns %0 on success and a negative error code on failure.
203 */
204 static int write_rcvrd_mst_node(struct ubifs_info *c,
205 struct ubifs_mst_node *mst)
206 {
207 int err = 0, lnum = UBIFS_MST_LNUM, sz = c->mst_node_alsz;
208 __le32 save_flags;
209
210 dbg_rcvry("recovery");
211
212 save_flags = mst->flags;
213 mst->flags |= cpu_to_le32(UBIFS_MST_RCVRY);
214
215 ubifs_prepare_node(c, mst, UBIFS_MST_NODE_SZ, 1);
216 err = ubifs_leb_change(c, lnum, mst, sz);
217 if (err)
218 goto out;
219 err = ubifs_leb_change(c, lnum + 1, mst, sz);
220 if (err)
221 goto out;
222 out:
223 mst->flags = save_flags;
224 return err;
225 }
226
227 /**
228 * ubifs_recover_master_node - recover the master node.
229 * @c: UBIFS file-system description object
230 *
231 * This function recovers the master node from corruption that may occur due to
232 * an unclean unmount.
233 *
234 * This function returns %0 on success and a negative error code on failure.
235 */
236 int ubifs_recover_master_node(struct ubifs_info *c)
237 {
238 void *buf1 = NULL, *buf2 = NULL, *cor1 = NULL, *cor2 = NULL;
239 struct ubifs_mst_node *mst1 = NULL, *mst2 = NULL, *mst;
240 const int sz = c->mst_node_alsz;
241 int err, offs1, offs2;
242
243 dbg_rcvry("recovery");
244
245 err = get_master_node(c, UBIFS_MST_LNUM, &buf1, &mst1, &cor1);
246 if (err)
247 goto out_free;
248
249 err = get_master_node(c, UBIFS_MST_LNUM + 1, &buf2, &mst2, &cor2);
250 if (err)
251 goto out_free;
252
253 if (mst1) {
254 offs1 = (void *)mst1 - buf1;
255 if ((le32_to_cpu(mst1->flags) & UBIFS_MST_RCVRY) &&
256 (offs1 == 0 && !cor1)) {
257 /*
258 * mst1 was written by recovery at offset 0 with no
259 * corruption.
260 */
261 dbg_rcvry("recovery recovery");
262 mst = mst1;
263 } else if (mst2) {
264 offs2 = (void *)mst2 - buf2;
265 if (offs1 == offs2) {
266 /* Same offset, so must be the same */
267 if (memcmp((void *)mst1 + UBIFS_CH_SZ,
268 (void *)mst2 + UBIFS_CH_SZ,
269 UBIFS_MST_NODE_SZ - UBIFS_CH_SZ))
270 goto out_err;
271 mst = mst1;
272 } else if (offs2 + sz == offs1) {
273 /* 1st LEB was written, 2nd was not */
274 if (cor1)
275 goto out_err;
276 mst = mst1;
277 } else if (offs1 == 0 &&
278 c->leb_size - offs2 - sz < sz) {
279 /* 1st LEB was unmapped and written, 2nd not */
280 if (cor1)
281 goto out_err;
282 mst = mst1;
283 } else
284 goto out_err;
285 } else {
286 /*
287 * 2nd LEB was unmapped and about to be written, so
288 * there must be only one master node in the first LEB
289 * and no corruption.
290 */
291 if (offs1 != 0 || cor1)
292 goto out_err;
293 mst = mst1;
294 }
295 } else {
296 if (!mst2)
297 goto out_err;
298 /*
299 * 1st LEB was unmapped and about to be written, so there must
300 * be no room left in 2nd LEB.
301 */
302 offs2 = (void *)mst2 - buf2;
303 if (offs2 + sz + sz <= c->leb_size)
304 goto out_err;
305 mst = mst2;
306 }
307
308 ubifs_msg(c, "recovered master node from LEB %d",
309 (mst == mst1 ? UBIFS_MST_LNUM : UBIFS_MST_LNUM + 1));
310
311 memcpy(c->mst_node, mst, UBIFS_MST_NODE_SZ);
312
313 if (c->ro_mount) {
314 /* Read-only mode. Keep a copy for switching to rw mode */
315 c->rcvrd_mst_node = kmalloc(sz, GFP_KERNEL);
316 if (!c->rcvrd_mst_node) {
317 err = -ENOMEM;
318 goto out_free;
319 }
320 memcpy(c->rcvrd_mst_node, c->mst_node, UBIFS_MST_NODE_SZ);
321
322 /*
323 * We had to recover the master node, which means there was an
324 * unclean reboot. However, it is possible that the master node
325 * is clean at this point, i.e., %UBIFS_MST_DIRTY is not set.
326 * E.g., consider the following chain of events:
327 *
328 * 1. UBIFS was cleanly unmounted, so the master node is clean
329 * 2. UBIFS is being mounted R/W and starts changing the master
330 * node in the first (%UBIFS_MST_LNUM). A power cut happens,
331 * so this LEB ends up with some amount of garbage at the
332 * end.
333 * 3. UBIFS is being mounted R/O. We reach this place and
334 * recover the master node from the second LEB
335 * (%UBIFS_MST_LNUM + 1). But we cannot update the media
336 * because we are being mounted R/O. We have to defer the
337 * operation.
338 * 4. However, this master node (@c->mst_node) is marked as
339 * clean (since the step 1). And if we just return, the
340 * mount code will be confused and won't recover the master
341 * node when it is re-mounter R/W later.
342 *
343 * Thus, to force the recovery by marking the master node as
344 * dirty.
345 */
346 c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
347 } else {
348 /* Write the recovered master node */
349 c->max_sqnum = le64_to_cpu(mst->ch.sqnum) - 1;
350 err = write_rcvrd_mst_node(c, c->mst_node);
351 if (err)
352 goto out_free;
353 }
354
355 vfree(buf2);
356 vfree(buf1);
357
358 return 0;
359
360 out_err:
361 err = -EINVAL;
362 out_free:
363 ubifs_err(c, "failed to recover master node");
364 if (mst1) {
365 ubifs_err(c, "dumping first master node");
366 ubifs_dump_node(c, mst1);
367 }
368 if (mst2) {
369 ubifs_err(c, "dumping second master node");
370 ubifs_dump_node(c, mst2);
371 }
372 vfree(buf2);
373 vfree(buf1);
374 return err;
375 }
376
377 /**
378 * ubifs_write_rcvrd_mst_node - write the recovered master node.
379 * @c: UBIFS file-system description object
380 *
381 * This function writes the master node that was recovered during mounting in
382 * read-only mode and must now be written because we are remounting rw.
383 *
384 * This function returns %0 on success and a negative error code on failure.
385 */
386 int ubifs_write_rcvrd_mst_node(struct ubifs_info *c)
387 {
388 int err;
389
390 if (!c->rcvrd_mst_node)
391 return 0;
392 c->rcvrd_mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
393 c->mst_node->flags |= cpu_to_le32(UBIFS_MST_DIRTY);
394 err = write_rcvrd_mst_node(c, c->rcvrd_mst_node);
395 if (err)
396 return err;
397 kfree(c->rcvrd_mst_node);
398 c->rcvrd_mst_node = NULL;
399 return 0;
400 }
401
402 /**
403 * is_last_write - determine if an offset was in the last write to a LEB.
404 * @c: UBIFS file-system description object
405 * @buf: buffer to check
406 * @offs: offset to check
407 *
408 * This function returns %1 if @offs was in the last write to the LEB whose data
409 * is in @buf, otherwise %0 is returned. The determination is made by checking
410 * for subsequent empty space starting from the next @c->max_write_size
411 * boundary.
412 */
413 static int is_last_write(const struct ubifs_info *c, void *buf, int offs)
414 {
415 int empty_offs, check_len;
416 uint8_t *p;
417
418 /*
419 * Round up to the next @c->max_write_size boundary i.e. @offs is in
420 * the last wbuf written. After that should be empty space.
421 */
422 empty_offs = ALIGN(offs + 1, c->max_write_size);
423 check_len = c->leb_size - empty_offs;
424 p = buf + empty_offs - offs;
425 return is_empty(p, check_len);
426 }
427
428 /**
429 * clean_buf - clean the data from an LEB sitting in a buffer.
430 * @c: UBIFS file-system description object
431 * @buf: buffer to clean
432 * @lnum: LEB number to clean
433 * @offs: offset from which to clean
434 * @len: length of buffer
435 *
436 * This function pads up to the next min_io_size boundary (if there is one) and
437 * sets empty space to all 0xff. @buf, @offs and @len are updated to the next
438 * @c->min_io_size boundary.
439 */
440 static void clean_buf(const struct ubifs_info *c, void **buf, int lnum,
441 int *offs, int *len)
442 {
443 int empty_offs, pad_len;
444
445 dbg_rcvry("cleaning corruption at %d:%d", lnum, *offs);
446
447 ubifs_assert(c, !(*offs & 7));
448 empty_offs = ALIGN(*offs, c->min_io_size);
449 pad_len = empty_offs - *offs;
450 ubifs_pad(c, *buf, pad_len);
451 *offs += pad_len;
452 *buf += pad_len;
453 *len -= pad_len;
454 memset(*buf, 0xff, c->leb_size - empty_offs);
455 }
456
457 /**
458 * no_more_nodes - determine if there are no more nodes in a buffer.
459 * @c: UBIFS file-system description object
460 * @buf: buffer to check
461 * @len: length of buffer
462 * @lnum: LEB number of the LEB from which @buf was read
463 * @offs: offset from which @buf was read
464 *
465 * This function ensures that the corrupted node at @offs is the last thing
466 * written to a LEB. This function returns %1 if more data is not found and
467 * %0 if more data is found.
468 */
469 static int no_more_nodes(const struct ubifs_info *c, void *buf, int len,
470 int lnum, int offs)
471 {
472 struct ubifs_ch *ch = buf;
473 int skip, dlen = le32_to_cpu(ch->len);
474
475 /* Check for empty space after the corrupt node's common header */
476 skip = ALIGN(offs + UBIFS_CH_SZ, c->max_write_size) - offs;
477 if (is_empty(buf + skip, len - skip))
478 return 1;
479 /*
480 * The area after the common header size is not empty, so the common
481 * header must be intact. Check it.
482 */
483 if (ubifs_check_node(c, buf, lnum, offs, 1, 0) != -EUCLEAN) {
484 dbg_rcvry("unexpected bad common header at %d:%d", lnum, offs);
485 return 0;
486 }
487 /* Now we know the corrupt node's length we can skip over it */
488 skip = ALIGN(offs + dlen, c->max_write_size) - offs;
489 /* After which there should be empty space */
490 if (is_empty(buf + skip, len - skip))
491 return 1;
492 dbg_rcvry("unexpected data at %d:%d", lnum, offs + skip);
493 return 0;
494 }
495
496 /**
497 * fix_unclean_leb - fix an unclean LEB.
498 * @c: UBIFS file-system description object
499 * @sleb: scanned LEB information
500 * @start: offset where scan started
501 */
502 static int fix_unclean_leb(struct ubifs_info *c, struct ubifs_scan_leb *sleb,
503 int start)
504 {
505 int lnum = sleb->lnum, endpt = start;
506
507 /* Get the end offset of the last node we are keeping */
508 if (!list_empty(&sleb->nodes)) {
509 struct ubifs_scan_node *snod;
510
511 snod = list_entry(sleb->nodes.prev,
512 struct ubifs_scan_node, list);
513 endpt = snod->offs + snod->len;
514 }
515
516 if (c->ro_mount && !c->remounting_rw) {
517 /* Add to recovery list */
518 struct ubifs_unclean_leb *ucleb;
519
520 dbg_rcvry("need to fix LEB %d start %d endpt %d",
521 lnum, start, sleb->endpt);
522 ucleb = kzalloc(sizeof(struct ubifs_unclean_leb), GFP_NOFS);
523 if (!ucleb)
524 return -ENOMEM;
525 ucleb->lnum = lnum;
526 ucleb->endpt = endpt;
527 list_add_tail(&ucleb->list, &c->unclean_leb_list);
528 } else {
529 /* Write the fixed LEB back to flash */
530 int err;
531
532 dbg_rcvry("fixing LEB %d start %d endpt %d",
533 lnum, start, sleb->endpt);
534 if (endpt == 0) {
535 err = ubifs_leb_unmap(c, lnum);
536 if (err)
537 return err;
538 } else {
539 int len = ALIGN(endpt, c->min_io_size);
540
541 if (start) {
542 err = ubifs_leb_read(c, lnum, sleb->buf, 0,
543 start, 1);
544 if (err)
545 return err;
546 }
547 /* Pad to min_io_size */
548 if (len > endpt) {
549 int pad_len = len - ALIGN(endpt, 8);
550
551 if (pad_len > 0) {
552 void *buf = sleb->buf + len - pad_len;
553
554 ubifs_pad(c, buf, pad_len);
555 }
556 }
557 err = ubifs_leb_change(c, lnum, sleb->buf, len);
558 if (err)
559 return err;
560 }
561 }
562 return 0;
563 }
564
565 /**
566 * drop_last_group - drop the last group of nodes.
567 * @sleb: scanned LEB information
568 * @offs: offset of dropped nodes is returned here
569 *
570 * This is a helper function for 'ubifs_recover_leb()' which drops the last
571 * group of nodes of the scanned LEB.
572 */
573 static void drop_last_group(struct ubifs_scan_leb *sleb, int *offs)
574 {
575 while (!list_empty(&sleb->nodes)) {
576 struct ubifs_scan_node *snod;
577 struct ubifs_ch *ch;
578
579 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
580 list);
581 ch = snod->node;
582 if (ch->group_type != UBIFS_IN_NODE_GROUP)
583 break;
584
585 dbg_rcvry("dropping grouped node at %d:%d",
586 sleb->lnum, snod->offs);
587 *offs = snod->offs;
588 list_del(&snod->list);
589 kfree(snod);
590 sleb->nodes_cnt -= 1;
591 }
592 }
593
594 /**
595 * drop_last_node - drop the last node.
596 * @sleb: scanned LEB information
597 * @offs: offset of dropped nodes is returned here
598 *
599 * This is a helper function for 'ubifs_recover_leb()' which drops the last
600 * node of the scanned LEB.
601 */
602 static void drop_last_node(struct ubifs_scan_leb *sleb, int *offs)
603 {
604 struct ubifs_scan_node *snod;
605
606 if (!list_empty(&sleb->nodes)) {
607 snod = list_entry(sleb->nodes.prev, struct ubifs_scan_node,
608 list);
609
610 dbg_rcvry("dropping last node at %d:%d",
611 sleb->lnum, snod->offs);
612 *offs = snod->offs;
613 list_del(&snod->list);
614 kfree(snod);
615 sleb->nodes_cnt -= 1;
616 }
617 }
618
619 /**
620 * ubifs_recover_leb - scan and recover a LEB.
621 * @c: UBIFS file-system description object
622 * @lnum: LEB number
623 * @offs: offset
624 * @sbuf: LEB-sized buffer to use
625 * @jhead: journal head number this LEB belongs to (%-1 if the LEB does not
626 * belong to any journal head)
627 *
628 * This function does a scan of a LEB, but caters for errors that might have
629 * been caused by the unclean unmount from which we are attempting to recover.
630 * Returns the scanned information on success and a negative error code on
631 * failure.
632 */
633 struct ubifs_scan_leb *ubifs_recover_leb(struct ubifs_info *c, int lnum,
634 int offs, void *sbuf, int jhead)
635 {
636 int ret = 0, err, len = c->leb_size - offs, start = offs, min_io_unit;
637 int grouped = jhead == -1 ? 0 : c->jheads[jhead].grouped;
638 struct ubifs_scan_leb *sleb;
639 void *buf = sbuf + offs;
640
641 dbg_rcvry("%d:%d, jhead %d, grouped %d", lnum, offs, jhead, grouped);
642
643 sleb = ubifs_start_scan(c, lnum, offs, sbuf);
644 if (IS_ERR(sleb))
645 return sleb;
646
647 ubifs_assert(c, len >= 8);
648 while (len >= 8) {
649 dbg_scan("look at LEB %d:%d (%d bytes left)",
650 lnum, offs, len);
651
652 cond_resched();
653
654 /*
655 * Scan quietly until there is an error from which we cannot
656 * recover
657 */
658 ret = ubifs_scan_a_node(c, buf, len, lnum, offs, 1);
659 if (ret == SCANNED_A_NODE) {
660 /* A valid node, and not a padding node */
661 struct ubifs_ch *ch = buf;
662 int node_len;
663
664 err = ubifs_add_snod(c, sleb, buf, offs);
665 if (err)
666 goto error;
667 node_len = ALIGN(le32_to_cpu(ch->len), 8);
668 offs += node_len;
669 buf += node_len;
670 len -= node_len;
671 } else if (ret > 0) {
672 /* Padding bytes or a valid padding node */
673 offs += ret;
674 buf += ret;
675 len -= ret;
676 } else if (ret == SCANNED_EMPTY_SPACE ||
677 ret == SCANNED_GARBAGE ||
678 ret == SCANNED_A_BAD_PAD_NODE ||
679 ret == SCANNED_A_CORRUPT_NODE) {
680 dbg_rcvry("found corruption (%d) at %d:%d",
681 ret, lnum, offs);
682 break;
683 } else {
684 ubifs_err(c, "unexpected return value %d", ret);
685 err = -EINVAL;
686 goto error;
687 }
688 }
689
690 if (ret == SCANNED_GARBAGE || ret == SCANNED_A_BAD_PAD_NODE) {
691 if (!is_last_write(c, buf, offs))
692 goto corrupted_rescan;
693 } else if (ret == SCANNED_A_CORRUPT_NODE) {
694 if (!no_more_nodes(c, buf, len, lnum, offs))
695 goto corrupted_rescan;
696 } else if (!is_empty(buf, len)) {
697 if (!is_last_write(c, buf, offs)) {
698 int corruption = first_non_ff(buf, len);
699
700 /*
701 * See header comment for this file for more
702 * explanations about the reasons we have this check.
703 */
704 ubifs_err(c, "corrupt empty space LEB %d:%d, corruption starts at %d",
705 lnum, offs, corruption);
706 /* Make sure we dump interesting non-0xFF data */
707 offs += corruption;
708 buf += corruption;
709 goto corrupted;
710 }
711 }
712
713 min_io_unit = round_down(offs, c->min_io_size);
714 if (grouped)
715 /*
716 * If nodes are grouped, always drop the incomplete group at
717 * the end.
718 */
719 drop_last_group(sleb, &offs);
720
721 if (jhead == GCHD) {
722 /*
723 * If this LEB belongs to the GC head then while we are in the
724 * middle of the same min. I/O unit keep dropping nodes. So
725 * basically, what we want is to make sure that the last min.
726 * I/O unit where we saw the corruption is dropped completely
727 * with all the uncorrupted nodes which may possibly sit there.
728 *
729 * In other words, let's name the min. I/O unit where the
730 * corruption starts B, and the previous min. I/O unit A. The
731 * below code tries to deal with a situation when half of B
732 * contains valid nodes or the end of a valid node, and the
733 * second half of B contains corrupted data or garbage. This
734 * means that UBIFS had been writing to B just before the power
735 * cut happened. I do not know how realistic is this scenario
736 * that half of the min. I/O unit had been written successfully
737 * and the other half not, but this is possible in our 'failure
738 * mode emulation' infrastructure at least.
739 *
740 * So what is the problem, why we need to drop those nodes? Why
741 * can't we just clean-up the second half of B by putting a
742 * padding node there? We can, and this works fine with one
743 * exception which was reproduced with power cut emulation
744 * testing and happens extremely rarely.
745 *
746 * Imagine the file-system is full, we run GC which starts
747 * moving valid nodes from LEB X to LEB Y (obviously, LEB Y is
748 * the current GC head LEB). The @c->gc_lnum is -1, which means
749 * that GC will retain LEB X and will try to continue. Imagine
750 * that LEB X is currently the dirtiest LEB, and the amount of
751 * used space in LEB Y is exactly the same as amount of free
752 * space in LEB X.
753 *
754 * And a power cut happens when nodes are moved from LEB X to
755 * LEB Y. We are here trying to recover LEB Y which is the GC
756 * head LEB. We find the min. I/O unit B as described above.
757 * Then we clean-up LEB Y by padding min. I/O unit. And later
758 * 'ubifs_rcvry_gc_commit()' function fails, because it cannot
759 * find a dirty LEB which could be GC'd into LEB Y! Even LEB X
760 * does not match because the amount of valid nodes there does
761 * not fit the free space in LEB Y any more! And this is
762 * because of the padding node which we added to LEB Y. The
763 * user-visible effect of this which I once observed and
764 * analysed is that we cannot mount the file-system with
765 * -ENOSPC error.
766 *
767 * So obviously, to make sure that situation does not happen we
768 * should free min. I/O unit B in LEB Y completely and the last
769 * used min. I/O unit in LEB Y should be A. This is basically
770 * what the below code tries to do.
771 */
772 while (offs > min_io_unit)
773 drop_last_node(sleb, &offs);
774 }
775
776 buf = sbuf + offs;
777 len = c->leb_size - offs;
778
779 clean_buf(c, &buf, lnum, &offs, &len);
780 ubifs_end_scan(c, sleb, lnum, offs);
781
782 err = fix_unclean_leb(c, sleb, start);
783 if (err)
784 goto error;
785
786 return sleb;
787
788 corrupted_rescan:
789 /* Re-scan the corrupted data with verbose messages */
790 ubifs_err(c, "corruption %d", ret);
791 ubifs_scan_a_node(c, buf, len, lnum, offs, 0);
792 corrupted:
793 ubifs_scanned_corruption(c, lnum, offs, buf);
794 err = -EUCLEAN;
795 error:
796 ubifs_err(c, "LEB %d scanning failed", lnum);
797 ubifs_scan_destroy(sleb);
798 return ERR_PTR(err);
799 }
800
801 /**
802 * get_cs_sqnum - get commit start sequence number.
803 * @c: UBIFS file-system description object
804 * @lnum: LEB number of commit start node
805 * @offs: offset of commit start node
806 * @cs_sqnum: commit start sequence number is returned here
807 *
808 * This function returns %0 on success and a negative error code on failure.
809 */
810 static int get_cs_sqnum(struct ubifs_info *c, int lnum, int offs,
811 unsigned long long *cs_sqnum)
812 {
813 struct ubifs_cs_node *cs_node = NULL;
814 int err, ret;
815
816 dbg_rcvry("at %d:%d", lnum, offs);
817 cs_node = kmalloc(UBIFS_CS_NODE_SZ, GFP_KERNEL);
818 if (!cs_node)
819 return -ENOMEM;
820 if (c->leb_size - offs < UBIFS_CS_NODE_SZ)
821 goto out_err;
822 err = ubifs_leb_read(c, lnum, (void *)cs_node, offs,
823 UBIFS_CS_NODE_SZ, 0);
824 if (err && err != -EBADMSG)
825 goto out_free;
826 ret = ubifs_scan_a_node(c, cs_node, UBIFS_CS_NODE_SZ, lnum, offs, 0);
827 if (ret != SCANNED_A_NODE) {
828 ubifs_err(c, "Not a valid node");
829 goto out_err;
830 }
831 if (cs_node->ch.node_type != UBIFS_CS_NODE) {
832 ubifs_err(c, "Node a CS node, type is %d", cs_node->ch.node_type);
833 goto out_err;
834 }
835 if (le64_to_cpu(cs_node->cmt_no) != c->cmt_no) {
836 ubifs_err(c, "CS node cmt_no %llu != current cmt_no %llu",
837 (unsigned long long)le64_to_cpu(cs_node->cmt_no),
838 c->cmt_no);
839 goto out_err;
840 }
841 *cs_sqnum = le64_to_cpu(cs_node->ch.sqnum);
842 dbg_rcvry("commit start sqnum %llu", *cs_sqnum);
843 kfree(cs_node);
844 return 0;
845
846 out_err:
847 err = -EINVAL;
848 out_free:
849 ubifs_err(c, "failed to get CS sqnum");
850 kfree(cs_node);
851 return err;
852 }
853
854 /**
855 * ubifs_recover_log_leb - scan and recover a log LEB.
856 * @c: UBIFS file-system description object
857 * @lnum: LEB number
858 * @offs: offset
859 * @sbuf: LEB-sized buffer to use
860 *
861 * This function does a scan of a LEB, but caters for errors that might have
862 * been caused by unclean reboots from which we are attempting to recover
863 * (assume that only the last log LEB can be corrupted by an unclean reboot).
864 *
865 * This function returns %0 on success and a negative error code on failure.
866 */
867 struct ubifs_scan_leb *ubifs_recover_log_leb(struct ubifs_info *c, int lnum,
868 int offs, void *sbuf)
869 {
870 struct ubifs_scan_leb *sleb;
871 int next_lnum;
872
873 dbg_rcvry("LEB %d", lnum);
874 next_lnum = lnum + 1;
875 if (next_lnum >= UBIFS_LOG_LNUM + c->log_lebs)
876 next_lnum = UBIFS_LOG_LNUM;
877 if (next_lnum != c->ltail_lnum) {
878 /*
879 * We can only recover at the end of the log, so check that the
880 * next log LEB is empty or out of date.
881 */
882 sleb = ubifs_scan(c, next_lnum, 0, sbuf, 0);
883 if (IS_ERR(sleb))
884 return sleb;
885 if (sleb->nodes_cnt) {
886 struct ubifs_scan_node *snod;
887 unsigned long long cs_sqnum = c->cs_sqnum;
888
889 snod = list_entry(sleb->nodes.next,
890 struct ubifs_scan_node, list);
891 if (cs_sqnum == 0) {
892 int err;
893
894 err = get_cs_sqnum(c, lnum, offs, &cs_sqnum);
895 if (err) {
896 ubifs_scan_destroy(sleb);
897 return ERR_PTR(err);
898 }
899 }
900 if (snod->sqnum > cs_sqnum) {
901 ubifs_err(c, "unrecoverable log corruption in LEB %d",
902 lnum);
903 ubifs_scan_destroy(sleb);
904 return ERR_PTR(-EUCLEAN);
905 }
906 }
907 ubifs_scan_destroy(sleb);
908 }
909 return ubifs_recover_leb(c, lnum, offs, sbuf, -1);
910 }
911
912 /**
913 * recover_head - recover a head.
914 * @c: UBIFS file-system description object
915 * @lnum: LEB number of head to recover
916 * @offs: offset of head to recover
917 * @sbuf: LEB-sized buffer to use
918 *
919 * This function ensures that there is no data on the flash at a head location.
920 *
921 * This function returns %0 on success and a negative error code on failure.
922 */
923 static int recover_head(struct ubifs_info *c, int lnum, int offs, void *sbuf)
924 {
925 int len = c->max_write_size, err;
926
927 if (offs + len > c->leb_size)
928 len = c->leb_size - offs;
929
930 if (!len)
931 return 0;
932
933 /* Read at the head location and check it is empty flash */
934 err = ubifs_leb_read(c, lnum, sbuf, offs, len, 1);
935 if (err || !is_empty(sbuf, len)) {
936 dbg_rcvry("cleaning head at %d:%d", lnum, offs);
937 if (offs == 0)
938 return ubifs_leb_unmap(c, lnum);
939 err = ubifs_leb_read(c, lnum, sbuf, 0, offs, 1);
940 if (err)
941 return err;
942 return ubifs_leb_change(c, lnum, sbuf, offs);
943 }
944
945 return 0;
946 }
947
948 /**
949 * ubifs_recover_inl_heads - recover index and LPT heads.
950 * @c: UBIFS file-system description object
951 * @sbuf: LEB-sized buffer to use
952 *
953 * This function ensures that there is no data on the flash at the index and
954 * LPT head locations.
955 *
956 * This deals with the recovery of a half-completed journal commit. UBIFS is
957 * careful never to overwrite the last version of the index or the LPT. Because
958 * the index and LPT are wandering trees, data from a half-completed commit will
959 * not be referenced anywhere in UBIFS. The data will be either in LEBs that are
960 * assumed to be empty and will be unmapped anyway before use, or in the index
961 * and LPT heads.
962 *
963 * This function returns %0 on success and a negative error code on failure.
964 */
965 int ubifs_recover_inl_heads(struct ubifs_info *c, void *sbuf)
966 {
967 int err;
968
969 ubifs_assert(c, !c->ro_mount || c->remounting_rw);
970
971 dbg_rcvry("checking index head at %d:%d", c->ihead_lnum, c->ihead_offs);
972 err = recover_head(c, c->ihead_lnum, c->ihead_offs, sbuf);
973 if (err)
974 return err;
975
976 dbg_rcvry("checking LPT head at %d:%d", c->nhead_lnum, c->nhead_offs);
977
978 return recover_head(c, c->nhead_lnum, c->nhead_offs, sbuf);
979 }
980
981 /**
982 * clean_an_unclean_leb - read and write a LEB to remove corruption.
983 * @c: UBIFS file-system description object
984 * @ucleb: unclean LEB information
985 * @sbuf: LEB-sized buffer to use
986 *
987 * This function reads a LEB up to a point pre-determined by the mount recovery,
988 * checks the nodes, and writes the result back to the flash, thereby cleaning
989 * off any following corruption, or non-fatal ECC errors.
990 *
991 * This function returns %0 on success and a negative error code on failure.
992 */
993 static int clean_an_unclean_leb(struct ubifs_info *c,
994 struct ubifs_unclean_leb *ucleb, void *sbuf)
995 {
996 int err, lnum = ucleb->lnum, offs = 0, len = ucleb->endpt, quiet = 1;
997 void *buf = sbuf;
998
999 dbg_rcvry("LEB %d len %d", lnum, len);
1000
1001 if (len == 0) {
1002 /* Nothing to read, just unmap it */
1003 return ubifs_leb_unmap(c, lnum);
1004 }
1005
1006 err = ubifs_leb_read(c, lnum, buf, offs, len, 0);
1007 if (err && err != -EBADMSG)
1008 return err;
1009
1010 while (len >= 8) {
1011 int ret;
1012
1013 cond_resched();
1014
1015 /* Scan quietly until there is an error */
1016 ret = ubifs_scan_a_node(c, buf, len, lnum, offs, quiet);
1017
1018 if (ret == SCANNED_A_NODE) {
1019 /* A valid node, and not a padding node */
1020 struct ubifs_ch *ch = buf;
1021 int node_len;
1022
1023 node_len = ALIGN(le32_to_cpu(ch->len), 8);
1024 offs += node_len;
1025 buf += node_len;
1026 len -= node_len;
1027 continue;
1028 }
1029
1030 if (ret > 0) {
1031 /* Padding bytes or a valid padding node */
1032 offs += ret;
1033 buf += ret;
1034 len -= ret;
1035 continue;
1036 }
1037
1038 if (ret == SCANNED_EMPTY_SPACE) {
1039 ubifs_err(c, "unexpected empty space at %d:%d",
1040 lnum, offs);
1041 return -EUCLEAN;
1042 }
1043
1044 if (quiet) {
1045 /* Redo the last scan but noisily */
1046 quiet = 0;
1047 continue;
1048 }
1049
1050 ubifs_scanned_corruption(c, lnum, offs, buf);
1051 return -EUCLEAN;
1052 }
1053
1054 /* Pad to min_io_size */
1055 len = ALIGN(ucleb->endpt, c->min_io_size);
1056 if (len > ucleb->endpt) {
1057 int pad_len = len - ALIGN(ucleb->endpt, 8);
1058
1059 if (pad_len > 0) {
1060 buf = c->sbuf + len - pad_len;
1061 ubifs_pad(c, buf, pad_len);
1062 }
1063 }
1064
1065 /* Write back the LEB atomically */
1066 err = ubifs_leb_change(c, lnum, sbuf, len);
1067 if (err)
1068 return err;
1069
1070 dbg_rcvry("cleaned LEB %d", lnum);
1071
1072 return 0;
1073 }
1074
1075 /**
1076 * ubifs_clean_lebs - clean LEBs recovered during read-only mount.
1077 * @c: UBIFS file-system description object
1078 * @sbuf: LEB-sized buffer to use
1079 *
1080 * This function cleans a LEB identified during recovery that needs to be
1081 * written but was not because UBIFS was mounted read-only. This happens when
1082 * remounting to read-write mode.
1083 *
1084 * This function returns %0 on success and a negative error code on failure.
1085 */
1086 int ubifs_clean_lebs(struct ubifs_info *c, void *sbuf)
1087 {
1088 dbg_rcvry("recovery");
1089 while (!list_empty(&c->unclean_leb_list)) {
1090 struct ubifs_unclean_leb *ucleb;
1091 int err;
1092
1093 ucleb = list_entry(c->unclean_leb_list.next,
1094 struct ubifs_unclean_leb, list);
1095 err = clean_an_unclean_leb(c, ucleb, sbuf);
1096 if (err)
1097 return err;
1098 list_del(&ucleb->list);
1099 kfree(ucleb);
1100 }
1101 return 0;
1102 }
1103
1104 /**
1105 * grab_empty_leb - grab an empty LEB to use as GC LEB and run commit.
1106 * @c: UBIFS file-system description object
1107 *
1108 * This is a helper function for 'ubifs_rcvry_gc_commit()' which grabs an empty
1109 * LEB to be used as GC LEB (@c->gc_lnum), and then runs the commit. Returns
1110 * zero in case of success and a negative error code in case of failure.
1111 */
1112 static int grab_empty_leb(struct ubifs_info *c)
1113 {
1114 int lnum, err;
1115
1116 /*
1117 * Note, it is very important to first search for an empty LEB and then
1118 * run the commit, not vice-versa. The reason is that there might be
1119 * only one empty LEB at the moment, the one which has been the
1120 * @c->gc_lnum just before the power cut happened. During the regular
1121 * UBIFS operation (not now) @c->gc_lnum is marked as "taken", so no
1122 * one but GC can grab it. But at this moment this single empty LEB is
1123 * not marked as taken, so if we run commit - what happens? Right, the
1124 * commit will grab it and write the index there. Remember that the
1125 * index always expands as long as there is free space, and it only
1126 * starts consolidating when we run out of space.
1127 *
1128 * IOW, if we run commit now, we might not be able to find a free LEB
1129 * after this.
1130 */
1131 lnum = ubifs_find_free_leb_for_idx(c);
1132 if (lnum < 0) {
1133 ubifs_err(c, "could not find an empty LEB");
1134 ubifs_dump_lprops(c);
1135 ubifs_dump_budg(c, &c->bi);
1136 return lnum;
1137 }
1138
1139 /* Reset the index flag */
1140 err = ubifs_change_one_lp(c, lnum, LPROPS_NC, LPROPS_NC, 0,
1141 LPROPS_INDEX, 0);
1142 if (err)
1143 return err;
1144
1145 c->gc_lnum = lnum;
1146 dbg_rcvry("found empty LEB %d, run commit", lnum);
1147
1148 return ubifs_run_commit(c);
1149 }
1150
1151 /**
1152 * ubifs_rcvry_gc_commit - recover the GC LEB number and run the commit.
1153 * @c: UBIFS file-system description object
1154 *
1155 * Out-of-place garbage collection requires always one empty LEB with which to
1156 * start garbage collection. The LEB number is recorded in c->gc_lnum and is
1157 * written to the master node on unmounting. In the case of an unclean unmount
1158 * the value of gc_lnum recorded in the master node is out of date and cannot
1159 * be used. Instead, recovery must allocate an empty LEB for this purpose.
1160 * However, there may not be enough empty space, in which case it must be
1161 * possible to GC the dirtiest LEB into the GC head LEB.
1162 *
1163 * This function also runs the commit which causes the TNC updates from
1164 * size-recovery and orphans to be written to the flash. That is important to
1165 * ensure correct replay order for subsequent mounts.
1166 *
1167 * This function returns %0 on success and a negative error code on failure.
1168 */
1169 int ubifs_rcvry_gc_commit(struct ubifs_info *c)
1170 {
1171 struct ubifs_wbuf *wbuf = &c->jheads[GCHD].wbuf;
1172 struct ubifs_lprops lp;
1173 int err;
1174
1175 dbg_rcvry("GC head LEB %d, offs %d", wbuf->lnum, wbuf->offs);
1176
1177 c->gc_lnum = -1;
1178 if (wbuf->lnum == -1 || wbuf->offs == c->leb_size)
1179 return grab_empty_leb(c);
1180
1181 err = ubifs_find_dirty_leb(c, &lp, wbuf->offs, 2);
1182 if (err) {
1183 if (err != -ENOSPC)
1184 return err;
1185
1186 dbg_rcvry("could not find a dirty LEB");
1187 return grab_empty_leb(c);
1188 }
1189
1190 ubifs_assert(c, !(lp.flags & LPROPS_INDEX));
1191 ubifs_assert(c, lp.free + lp.dirty >= wbuf->offs);
1192
1193 /*
1194 * We run the commit before garbage collection otherwise subsequent
1195 * mounts will see the GC and orphan deletion in a different order.
1196 */
1197 dbg_rcvry("committing");
1198 err = ubifs_run_commit(c);
1199 if (err)
1200 return err;
1201
1202 dbg_rcvry("GC'ing LEB %d", lp.lnum);
1203 mutex_lock_nested(&wbuf->io_mutex, wbuf->jhead);
1204 err = ubifs_garbage_collect_leb(c, &lp);
1205 if (err >= 0) {
1206 int err2 = ubifs_wbuf_sync_nolock(wbuf);
1207
1208 if (err2)
1209 err = err2;
1210 }
1211 mutex_unlock(&wbuf->io_mutex);
1212 if (err < 0) {
1213 ubifs_err(c, "GC failed, error %d", err);
1214 if (err == -EAGAIN)
1215 err = -EINVAL;
1216 return err;
1217 }
1218
1219 ubifs_assert(c, err == LEB_RETAINED);
1220 if (err != LEB_RETAINED)
1221 return -EINVAL;
1222
1223 err = ubifs_leb_unmap(c, c->gc_lnum);
1224 if (err)
1225 return err;
1226
1227 dbg_rcvry("allocated LEB %d for GC", lp.lnum);
1228 return 0;
1229 }
1230
1231 /**
1232 * struct size_entry - inode size information for recovery.
1233 * @rb: link in the RB-tree of sizes
1234 * @inum: inode number
1235 * @i_size: size on inode
1236 * @d_size: maximum size based on data nodes
1237 * @exists: indicates whether the inode exists
1238 * @inode: inode if pinned in memory awaiting rw mode to fix it
1239 */
1240 struct size_entry {
1241 struct rb_node rb;
1242 ino_t inum;
1243 loff_t i_size;
1244 loff_t d_size;
1245 int exists;
1246 struct inode *inode;
1247 };
1248
1249 /**
1250 * add_ino - add an entry to the size tree.
1251 * @c: UBIFS file-system description object
1252 * @inum: inode number
1253 * @i_size: size on inode
1254 * @d_size: maximum size based on data nodes
1255 * @exists: indicates whether the inode exists
1256 */
1257 static int add_ino(struct ubifs_info *c, ino_t inum, loff_t i_size,
1258 loff_t d_size, int exists)
1259 {
1260 struct rb_node **p = &c->size_tree.rb_node, *parent = NULL;
1261 struct size_entry *e;
1262
1263 while (*p) {
1264 parent = *p;
1265 e = rb_entry(parent, struct size_entry, rb);
1266 if (inum < e->inum)
1267 p = &(*p)->rb_left;
1268 else
1269 p = &(*p)->rb_right;
1270 }
1271
1272 e = kzalloc(sizeof(struct size_entry), GFP_KERNEL);
1273 if (!e)
1274 return -ENOMEM;
1275
1276 e->inum = inum;
1277 e->i_size = i_size;
1278 e->d_size = d_size;
1279 e->exists = exists;
1280
1281 rb_link_node(&e->rb, parent, p);
1282 rb_insert_color(&e->rb, &c->size_tree);
1283
1284 return 0;
1285 }
1286
1287 /**
1288 * find_ino - find an entry on the size tree.
1289 * @c: UBIFS file-system description object
1290 * @inum: inode number
1291 */
1292 static struct size_entry *find_ino(struct ubifs_info *c, ino_t inum)
1293 {
1294 struct rb_node *p = c->size_tree.rb_node;
1295 struct size_entry *e;
1296
1297 while (p) {
1298 e = rb_entry(p, struct size_entry, rb);
1299 if (inum < e->inum)
1300 p = p->rb_left;
1301 else if (inum > e->inum)
1302 p = p->rb_right;
1303 else
1304 return e;
1305 }
1306 return NULL;
1307 }
1308
1309 /**
1310 * remove_ino - remove an entry from the size tree.
1311 * @c: UBIFS file-system description object
1312 * @inum: inode number
1313 */
1314 static void remove_ino(struct ubifs_info *c, ino_t inum)
1315 {
1316 struct size_entry *e = find_ino(c, inum);
1317
1318 if (!e)
1319 return;
1320 rb_erase(&e->rb, &c->size_tree);
1321 kfree(e);
1322 }
1323
1324 /**
1325 * ubifs_destroy_size_tree - free resources related to the size tree.
1326 * @c: UBIFS file-system description object
1327 */
1328 void ubifs_destroy_size_tree(struct ubifs_info *c)
1329 {
1330 struct size_entry *e, *n;
1331
1332 rbtree_postorder_for_each_entry_safe(e, n, &c->size_tree, rb) {
1333 iput(e->inode);
1334 kfree(e);
1335 }
1336
1337 c->size_tree = RB_ROOT;
1338 }
1339
1340 /**
1341 * ubifs_recover_size_accum - accumulate inode sizes for recovery.
1342 * @c: UBIFS file-system description object
1343 * @key: node key
1344 * @deletion: node is for a deletion
1345 * @new_size: inode size
1346 *
1347 * This function has two purposes:
1348 * 1) to ensure there are no data nodes that fall outside the inode size
1349 * 2) to ensure there are no data nodes for inodes that do not exist
1350 * To accomplish those purposes, a rb-tree is constructed containing an entry
1351 * for each inode number in the journal that has not been deleted, and recording
1352 * the size from the inode node, the maximum size of any data node (also altered
1353 * by truncations) and a flag indicating a inode number for which no inode node
1354 * was present in the journal.
1355 *
1356 * Note that there is still the possibility that there are data nodes that have
1357 * been committed that are beyond the inode size, however the only way to find
1358 * them would be to scan the entire index. Alternatively, some provision could
1359 * be made to record the size of inodes at the start of commit, which would seem
1360 * very cumbersome for a scenario that is quite unlikely and the only negative
1361 * consequence of which is wasted space.
1362 *
1363 * This functions returns %0 on success and a negative error code on failure.
1364 */
1365 int ubifs_recover_size_accum(struct ubifs_info *c, union ubifs_key *key,
1366 int deletion, loff_t new_size)
1367 {
1368 ino_t inum = key_inum(c, key);
1369 struct size_entry *e;
1370 int err;
1371
1372 switch (key_type(c, key)) {
1373 case UBIFS_INO_KEY:
1374 if (deletion)
1375 remove_ino(c, inum);
1376 else {
1377 e = find_ino(c, inum);
1378 if (e) {
1379 e->i_size = new_size;
1380 e->exists = 1;
1381 } else {
1382 err = add_ino(c, inum, new_size, 0, 1);
1383 if (err)
1384 return err;
1385 }
1386 }
1387 break;
1388 case UBIFS_DATA_KEY:
1389 e = find_ino(c, inum);
1390 if (e) {
1391 if (new_size > e->d_size)
1392 e->d_size = new_size;
1393 } else {
1394 err = add_ino(c, inum, 0, new_size, 0);
1395 if (err)
1396 return err;
1397 }
1398 break;
1399 case UBIFS_TRUN_KEY:
1400 e = find_ino(c, inum);
1401 if (e)
1402 e->d_size = new_size;
1403 break;
1404 }
1405 return 0;
1406 }
1407
1408 /**
1409 * fix_size_in_place - fix inode size in place on flash.
1410 * @c: UBIFS file-system description object
1411 * @e: inode size information for recovery
1412 */
1413 static int fix_size_in_place(struct ubifs_info *c, struct size_entry *e)
1414 {
1415 struct ubifs_ino_node *ino = c->sbuf;
1416 unsigned char *p;
1417 union ubifs_key key;
1418 int err, lnum, offs, len;
1419 loff_t i_size;
1420 uint32_t crc;
1421
1422 /* Locate the inode node LEB number and offset */
1423 ino_key_init(c, &key, e->inum);
1424 err = ubifs_tnc_locate(c, &key, ino, &lnum, &offs);
1425 if (err)
1426 goto out;
1427 /*
1428 * If the size recorded on the inode node is greater than the size that
1429 * was calculated from nodes in the journal then don't change the inode.
1430 */
1431 i_size = le64_to_cpu(ino->size);
1432 if (i_size >= e->d_size)
1433 return 0;
1434 /* Read the LEB */
1435 err = ubifs_leb_read(c, lnum, c->sbuf, 0, c->leb_size, 1);
1436 if (err)
1437 goto out;
1438 /* Change the size field and recalculate the CRC */
1439 ino = c->sbuf + offs;
1440 ino->size = cpu_to_le64(e->d_size);
1441 len = le32_to_cpu(ino->ch.len);
1442 crc = crc32(UBIFS_CRC32_INIT, (void *)ino + 8, len - 8);
1443 ino->ch.crc = cpu_to_le32(crc);
1444 /* Work out where data in the LEB ends and free space begins */
1445 p = c->sbuf;
1446 len = c->leb_size - 1;
1447 while (p[len] == 0xff)
1448 len -= 1;
1449 len = ALIGN(len + 1, c->min_io_size);
1450 /* Atomically write the fixed LEB back again */
1451 err = ubifs_leb_change(c, lnum, c->sbuf, len);
1452 if (err)
1453 goto out;
1454 dbg_rcvry("inode %lu at %d:%d size %lld -> %lld",
1455 (unsigned long)e->inum, lnum, offs, i_size, e->d_size);
1456 return 0;
1457
1458 out:
1459 ubifs_warn(c, "inode %lu failed to fix size %lld -> %lld error %d",
1460 (unsigned long)e->inum, e->i_size, e->d_size, err);
1461 return err;
1462 }
1463
1464 /**
1465 * ubifs_recover_size - recover inode size.
1466 * @c: UBIFS file-system description object
1467 *
1468 * This function attempts to fix inode size discrepancies identified by the
1469 * 'ubifs_recover_size_accum()' function.
1470 *
1471 * This functions returns %0 on success and a negative error code on failure.
1472 */
1473 int ubifs_recover_size(struct ubifs_info *c)
1474 {
1475 struct rb_node *this = rb_first(&c->size_tree);
1476
1477 while (this) {
1478 struct size_entry *e;
1479 int err;
1480
1481 e = rb_entry(this, struct size_entry, rb);
1482 if (!e->exists) {
1483 union ubifs_key key;
1484
1485 ino_key_init(c, &key, e->inum);
1486 err = ubifs_tnc_lookup(c, &key, c->sbuf);
1487 if (err && err != -ENOENT)
1488 return err;
1489 if (err == -ENOENT) {
1490 /* Remove data nodes that have no inode */
1491 dbg_rcvry("removing ino %lu",
1492 (unsigned long)e->inum);
1493 err = ubifs_tnc_remove_ino(c, e->inum);
1494 if (err)
1495 return err;
1496 } else {
1497 struct ubifs_ino_node *ino = c->sbuf;
1498
1499 e->exists = 1;
1500 e->i_size = le64_to_cpu(ino->size);
1501 }
1502 }
1503
1504 if (e->exists && e->i_size < e->d_size) {
1505 if (c->ro_mount) {
1506 /* Fix the inode size and pin it in memory */
1507 struct inode *inode;
1508 struct ubifs_inode *ui;
1509
1510 ubifs_assert(c, !e->inode);
1511
1512 inode = ubifs_iget(c->vfs_sb, e->inum);
1513 if (IS_ERR(inode))
1514 return PTR_ERR(inode);
1515
1516 ui = ubifs_inode(inode);
1517 if (inode->i_size < e->d_size) {
1518 dbg_rcvry("ino %lu size %lld -> %lld",
1519 (unsigned long)e->inum,
1520 inode->i_size, e->d_size);
1521 inode->i_size = e->d_size;
1522 ui->ui_size = e->d_size;
1523 ui->synced_i_size = e->d_size;
1524 e->inode = inode;
1525 this = rb_next(this);
1526 continue;
1527 }
1528 iput(inode);
1529 } else {
1530 /* Fix the size in place */
1531 err = fix_size_in_place(c, e);
1532 if (err)
1533 return err;
1534 iput(e->inode);
1535 }
1536 }
1537
1538 this = rb_next(this);
1539 rb_erase(&e->rb, &c->size_tree);
1540 kfree(e);
1541 }
1542
1543 return 0;
1544 }