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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * linux/fs/jbd2/recovery.c
4 *
5 * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
6 *
7 * Copyright 1999-2000 Red Hat Software --- All Rights Reserved
8 *
9 * Journal recovery routines for the generic filesystem journaling code;
10 * part of the ext2fs journaling system.
11 */
12
13#ifndef __KERNEL__
14#include "jfs_user.h"
15#else
16#include <linux/time.h>
17#include <linux/fs.h>
18#include <linux/jbd2.h>
19#include <linux/errno.h>
20#include <linux/crc32.h>
21#include <linux/blkdev.h>
22#endif
23
24/*
25 * Maintain information about the progress of the recovery job, so that
26 * the different passes can carry information between them.
27 */
28struct recovery_info
29{
30 tid_t start_transaction;
31 tid_t end_transaction;
32
33 int nr_replays;
34 int nr_revokes;
35 int nr_revoke_hits;
36};
37
38static int do_one_pass(journal_t *journal,
39 struct recovery_info *info, enum passtype pass);
40static int scan_revoke_records(journal_t *, struct buffer_head *,
41 tid_t, struct recovery_info *);
42
43#ifdef __KERNEL__
44
45/* Release readahead buffers after use */
46static void journal_brelse_array(struct buffer_head *b[], int n)
47{
48 while (--n >= 0)
49 brelse (b[n]);
50}
51
52
53/*
54 * When reading from the journal, we are going through the block device
55 * layer directly and so there is no readahead being done for us. We
56 * need to implement any readahead ourselves if we want it to happen at
57 * all. Recovery is basically one long sequential read, so make sure we
58 * do the IO in reasonably large chunks.
59 *
60 * This is not so critical that we need to be enormously clever about
61 * the readahead size, though. 128K is a purely arbitrary, good-enough
62 * fixed value.
63 */
64
65#define MAXBUF 8
66static int do_readahead(journal_t *journal, unsigned int start)
67{
68 int err;
69 unsigned int max, nbufs, next;
70 unsigned long long blocknr;
71 struct buffer_head *bh;
72
73 struct buffer_head * bufs[MAXBUF];
74
75 /* Do up to 128K of readahead */
76 max = start + (128 * 1024 / journal->j_blocksize);
77 if (max > journal->j_total_len)
78 max = journal->j_total_len;
79
80 /* Do the readahead itself. We'll submit MAXBUF buffer_heads at
81 * a time to the block device IO layer. */
82
83 nbufs = 0;
84
85 for (next = start; next < max; next++) {
86 err = jbd2_journal_bmap(journal, next, &blocknr);
87
88 if (err) {
89 printk(KERN_ERR "JBD2: bad block at offset %u\n",
90 next);
91 goto failed;
92 }
93
94 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
95 if (!bh) {
96 err = -ENOMEM;
97 goto failed;
98 }
99
100 if (!buffer_uptodate(bh) && !buffer_locked(bh)) {
101 bufs[nbufs++] = bh;
102 if (nbufs == MAXBUF) {
103 bh_readahead_batch(nbufs, bufs, 0);
104 journal_brelse_array(bufs, nbufs);
105 nbufs = 0;
106 }
107 } else
108 brelse(bh);
109 }
110
111 if (nbufs)
112 bh_readahead_batch(nbufs, bufs, 0);
113 err = 0;
114
115failed:
116 if (nbufs)
117 journal_brelse_array(bufs, nbufs);
118 return err;
119}
120
121#endif /* __KERNEL__ */
122
123
124/*
125 * Read a block from the journal
126 */
127
128static int jread(struct buffer_head **bhp, journal_t *journal,
129 unsigned int offset)
130{
131 int err;
132 unsigned long long blocknr;
133 struct buffer_head *bh;
134
135 *bhp = NULL;
136
137 if (offset >= journal->j_total_len) {
138 printk(KERN_ERR "JBD2: corrupted journal superblock\n");
139 return -EFSCORRUPTED;
140 }
141
142 err = jbd2_journal_bmap(journal, offset, &blocknr);
143
144 if (err) {
145 printk(KERN_ERR "JBD2: bad block at offset %u\n",
146 offset);
147 return err;
148 }
149
150 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
151 if (!bh)
152 return -ENOMEM;
153
154 if (!buffer_uptodate(bh)) {
155 /*
156 * If this is a brand new buffer, start readahead.
157 * Otherwise, we assume we are already reading it.
158 */
159 bool need_readahead = !buffer_req(bh);
160
161 bh_read_nowait(bh, 0);
162 if (need_readahead)
163 do_readahead(journal, offset);
164 wait_on_buffer(bh);
165 }
166
167 if (!buffer_uptodate(bh)) {
168 printk(KERN_ERR "JBD2: Failed to read block at offset %u\n",
169 offset);
170 brelse(bh);
171 return -EIO;
172 }
173
174 *bhp = bh;
175 return 0;
176}
177
178static int jbd2_descriptor_block_csum_verify(journal_t *j, void *buf)
179{
180 struct jbd2_journal_block_tail *tail;
181 __be32 provided;
182 __u32 calculated;
183
184 if (!jbd2_journal_has_csum_v2or3(j))
185 return 1;
186
187 tail = (struct jbd2_journal_block_tail *)((char *)buf +
188 j->j_blocksize - sizeof(struct jbd2_journal_block_tail));
189 provided = tail->t_checksum;
190 tail->t_checksum = 0;
191 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
192 tail->t_checksum = provided;
193
194 return provided == cpu_to_be32(calculated);
195}
196
197/*
198 * Count the number of in-use tags in a journal descriptor block.
199 */
200
201static int count_tags(journal_t *journal, struct buffer_head *bh)
202{
203 char * tagp;
204 journal_block_tag_t tag;
205 int nr = 0, size = journal->j_blocksize;
206 int tag_bytes = journal_tag_bytes(journal);
207
208 if (jbd2_journal_has_csum_v2or3(journal))
209 size -= sizeof(struct jbd2_journal_block_tail);
210
211 tagp = &bh->b_data[sizeof(journal_header_t)];
212
213 while ((tagp - bh->b_data + tag_bytes) <= size) {
214 memcpy(&tag, tagp, sizeof(tag));
215
216 nr++;
217 tagp += tag_bytes;
218 if (!(tag.t_flags & cpu_to_be16(JBD2_FLAG_SAME_UUID)))
219 tagp += 16;
220
221 if (tag.t_flags & cpu_to_be16(JBD2_FLAG_LAST_TAG))
222 break;
223 }
224
225 return nr;
226}
227
228
229/* Make sure we wrap around the log correctly! */
230#define wrap(journal, var) \
231do { \
232 unsigned long _wrap_last = \
233 jbd2_has_feature_fast_commit(journal) ? \
234 (journal)->j_fc_last : (journal)->j_last; \
235 \
236 if (var >= _wrap_last) \
237 var -= (_wrap_last - (journal)->j_first); \
238} while (0)
239
240static int fc_do_one_pass(journal_t *journal,
241 struct recovery_info *info, enum passtype pass)
242{
243 unsigned int expected_commit_id = info->end_transaction;
244 unsigned long next_fc_block;
245 struct buffer_head *bh;
246 int err = 0;
247
248 next_fc_block = journal->j_fc_first;
249 if (!journal->j_fc_replay_callback)
250 return 0;
251
252 while (next_fc_block <= journal->j_fc_last) {
253 jbd2_debug(3, "Fast commit replay: next block %ld\n",
254 next_fc_block);
255 err = jread(&bh, journal, next_fc_block);
256 if (err) {
257 jbd2_debug(3, "Fast commit replay: read error\n");
258 break;
259 }
260
261 err = journal->j_fc_replay_callback(journal, bh, pass,
262 next_fc_block - journal->j_fc_first,
263 expected_commit_id);
264 brelse(bh);
265 next_fc_block++;
266 if (err < 0 || err == JBD2_FC_REPLAY_STOP)
267 break;
268 err = 0;
269 }
270
271 if (err)
272 jbd2_debug(3, "Fast commit replay failed, err = %d\n", err);
273
274 return err;
275}
276
277/**
278 * jbd2_journal_recover - recovers a on-disk journal
279 * @journal: the journal to recover
280 *
281 * The primary function for recovering the log contents when mounting a
282 * journaled device.
283 *
284 * Recovery is done in three passes. In the first pass, we look for the
285 * end of the log. In the second, we assemble the list of revoke
286 * blocks. In the third and final pass, we replay any un-revoked blocks
287 * in the log.
288 */
289int jbd2_journal_recover(journal_t *journal)
290{
291 int err, err2;
292 journal_superblock_t * sb;
293
294 struct recovery_info info;
295
296 memset(&info, 0, sizeof(info));
297 sb = journal->j_superblock;
298
299 /*
300 * The journal superblock's s_start field (the current log head)
301 * is always zero if, and only if, the journal was cleanly
302 * unmounted.
303 */
304
305 if (!sb->s_start) {
306 jbd2_debug(1, "No recovery required, last transaction %d\n",
307 be32_to_cpu(sb->s_sequence));
308 journal->j_transaction_sequence = be32_to_cpu(sb->s_sequence) + 1;
309 return 0;
310 }
311
312 err = do_one_pass(journal, &info, PASS_SCAN);
313 if (!err)
314 err = do_one_pass(journal, &info, PASS_REVOKE);
315 if (!err)
316 err = do_one_pass(journal, &info, PASS_REPLAY);
317
318 jbd2_debug(1, "JBD2: recovery, exit status %d, "
319 "recovered transactions %u to %u\n",
320 err, info.start_transaction, info.end_transaction);
321 jbd2_debug(1, "JBD2: Replayed %d and revoked %d/%d blocks\n",
322 info.nr_replays, info.nr_revoke_hits, info.nr_revokes);
323
324 /* Restart the log at the next transaction ID, thus invalidating
325 * any existing commit records in the log. */
326 journal->j_transaction_sequence = ++info.end_transaction;
327
328 jbd2_journal_clear_revoke(journal);
329 err2 = sync_blockdev(journal->j_fs_dev);
330 if (!err)
331 err = err2;
332 /* Make sure all replayed data is on permanent storage */
333 if (journal->j_flags & JBD2_BARRIER) {
334 err2 = blkdev_issue_flush(journal->j_fs_dev);
335 if (!err)
336 err = err2;
337 }
338 return err;
339}
340
341/**
342 * jbd2_journal_skip_recovery - Start journal and wipe exiting records
343 * @journal: journal to startup
344 *
345 * Locate any valid recovery information from the journal and set up the
346 * journal structures in memory to ignore it (presumably because the
347 * caller has evidence that it is out of date).
348 * This function doesn't appear to be exported..
349 *
350 * We perform one pass over the journal to allow us to tell the user how
351 * much recovery information is being erased, and to let us initialise
352 * the journal transaction sequence numbers to the next unused ID.
353 */
354int jbd2_journal_skip_recovery(journal_t *journal)
355{
356 int err;
357
358 struct recovery_info info;
359
360 memset (&info, 0, sizeof(info));
361
362 err = do_one_pass(journal, &info, PASS_SCAN);
363
364 if (err) {
365 printk(KERN_ERR "JBD2: error %d scanning journal\n", err);
366 ++journal->j_transaction_sequence;
367 } else {
368#ifdef CONFIG_JBD2_DEBUG
369 int dropped = info.end_transaction -
370 be32_to_cpu(journal->j_superblock->s_sequence);
371 jbd2_debug(1,
372 "JBD2: ignoring %d transaction%s from the journal.\n",
373 dropped, (dropped == 1) ? "" : "s");
374#endif
375 journal->j_transaction_sequence = ++info.end_transaction;
376 }
377
378 journal->j_tail = 0;
379 return err;
380}
381
382static inline unsigned long long read_tag_block(journal_t *journal,
383 journal_block_tag_t *tag)
384{
385 unsigned long long block = be32_to_cpu(tag->t_blocknr);
386 if (jbd2_has_feature_64bit(journal))
387 block |= (u64)be32_to_cpu(tag->t_blocknr_high) << 32;
388 return block;
389}
390
391/*
392 * calc_chksums calculates the checksums for the blocks described in the
393 * descriptor block.
394 */
395static int calc_chksums(journal_t *journal, struct buffer_head *bh,
396 unsigned long *next_log_block, __u32 *crc32_sum)
397{
398 int i, num_blks, err;
399 unsigned long io_block;
400 struct buffer_head *obh;
401
402 num_blks = count_tags(journal, bh);
403 /* Calculate checksum of the descriptor block. */
404 *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size);
405
406 for (i = 0; i < num_blks; i++) {
407 io_block = (*next_log_block)++;
408 wrap(journal, *next_log_block);
409 err = jread(&obh, journal, io_block);
410 if (err) {
411 printk(KERN_ERR "JBD2: IO error %d recovering block "
412 "%lu in log\n", err, io_block);
413 return 1;
414 } else {
415 *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data,
416 obh->b_size);
417 }
418 put_bh(obh);
419 }
420 return 0;
421}
422
423static int jbd2_commit_block_csum_verify(journal_t *j, void *buf)
424{
425 struct commit_header *h;
426 __be32 provided;
427 __u32 calculated;
428
429 if (!jbd2_journal_has_csum_v2or3(j))
430 return 1;
431
432 h = buf;
433 provided = h->h_chksum[0];
434 h->h_chksum[0] = 0;
435 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
436 h->h_chksum[0] = provided;
437
438 return provided == cpu_to_be32(calculated);
439}
440
441static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag,
442 journal_block_tag3_t *tag3,
443 void *buf, __u32 sequence)
444{
445 __u32 csum32;
446 __be32 seq;
447
448 if (!jbd2_journal_has_csum_v2or3(j))
449 return 1;
450
451 seq = cpu_to_be32(sequence);
452 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
453 csum32 = jbd2_chksum(j, csum32, buf, j->j_blocksize);
454
455 if (jbd2_has_feature_csum3(j))
456 return tag3->t_checksum == cpu_to_be32(csum32);
457 else
458 return tag->t_checksum == cpu_to_be16(csum32);
459}
460
461static int do_one_pass(journal_t *journal,
462 struct recovery_info *info, enum passtype pass)
463{
464 unsigned int first_commit_ID, next_commit_ID;
465 unsigned long next_log_block;
466 int err, success = 0;
467 journal_superblock_t * sb;
468 journal_header_t * tmp;
469 struct buffer_head * bh;
470 unsigned int sequence;
471 int blocktype;
472 int tag_bytes = journal_tag_bytes(journal);
473 __u32 crc32_sum = ~0; /* Transactional Checksums */
474 int descr_csum_size = 0;
475 int block_error = 0;
476 bool need_check_commit_time = false;
477 __u64 last_trans_commit_time = 0, commit_time;
478
479 /*
480 * First thing is to establish what we expect to find in the log
481 * (in terms of transaction IDs), and where (in terms of log
482 * block offsets): query the superblock.
483 */
484
485 sb = journal->j_superblock;
486 next_commit_ID = be32_to_cpu(sb->s_sequence);
487 next_log_block = be32_to_cpu(sb->s_start);
488
489 first_commit_ID = next_commit_ID;
490 if (pass == PASS_SCAN)
491 info->start_transaction = first_commit_ID;
492
493 jbd2_debug(1, "Starting recovery pass %d\n", pass);
494
495 /*
496 * Now we walk through the log, transaction by transaction,
497 * making sure that each transaction has a commit block in the
498 * expected place. Each complete transaction gets replayed back
499 * into the main filesystem.
500 */
501
502 while (1) {
503 int flags;
504 char * tagp;
505 journal_block_tag_t tag;
506 struct buffer_head * obh;
507 struct buffer_head * nbh;
508
509 cond_resched();
510
511 /* If we already know where to stop the log traversal,
512 * check right now that we haven't gone past the end of
513 * the log. */
514
515 if (pass != PASS_SCAN)
516 if (tid_geq(next_commit_ID, info->end_transaction))
517 break;
518
519 jbd2_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
520 next_commit_ID, next_log_block,
521 jbd2_has_feature_fast_commit(journal) ?
522 journal->j_fc_last : journal->j_last);
523
524 /* Skip over each chunk of the transaction looking
525 * either the next descriptor block or the final commit
526 * record. */
527
528 jbd2_debug(3, "JBD2: checking block %ld\n", next_log_block);
529 err = jread(&bh, journal, next_log_block);
530 if (err)
531 goto failed;
532
533 next_log_block++;
534 wrap(journal, next_log_block);
535
536 /* What kind of buffer is it?
537 *
538 * If it is a descriptor block, check that it has the
539 * expected sequence number. Otherwise, we're all done
540 * here. */
541
542 tmp = (journal_header_t *)bh->b_data;
543
544 if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) {
545 brelse(bh);
546 break;
547 }
548
549 blocktype = be32_to_cpu(tmp->h_blocktype);
550 sequence = be32_to_cpu(tmp->h_sequence);
551 jbd2_debug(3, "Found magic %d, sequence %d\n",
552 blocktype, sequence);
553
554 if (sequence != next_commit_ID) {
555 brelse(bh);
556 break;
557 }
558
559 /* OK, we have a valid descriptor block which matches
560 * all of the sequence number checks. What are we going
561 * to do with it? That depends on the pass... */
562
563 switch(blocktype) {
564 case JBD2_DESCRIPTOR_BLOCK:
565 /* Verify checksum first */
566 if (jbd2_journal_has_csum_v2or3(journal))
567 descr_csum_size =
568 sizeof(struct jbd2_journal_block_tail);
569 if (descr_csum_size > 0 &&
570 !jbd2_descriptor_block_csum_verify(journal,
571 bh->b_data)) {
572 /*
573 * PASS_SCAN can see stale blocks due to lazy
574 * journal init. Don't error out on those yet.
575 */
576 if (pass != PASS_SCAN) {
577 pr_err("JBD2: Invalid checksum recovering block %lu in log\n",
578 next_log_block);
579 err = -EFSBADCRC;
580 brelse(bh);
581 goto failed;
582 }
583 need_check_commit_time = true;
584 jbd2_debug(1,
585 "invalid descriptor block found in %lu\n",
586 next_log_block);
587 }
588
589 /* If it is a valid descriptor block, replay it
590 * in pass REPLAY; if journal_checksums enabled, then
591 * calculate checksums in PASS_SCAN, otherwise,
592 * just skip over the blocks it describes. */
593 if (pass != PASS_REPLAY) {
594 if (pass == PASS_SCAN &&
595 jbd2_has_feature_checksum(journal) &&
596 !need_check_commit_time &&
597 !info->end_transaction) {
598 if (calc_chksums(journal, bh,
599 &next_log_block,
600 &crc32_sum)) {
601 put_bh(bh);
602 break;
603 }
604 put_bh(bh);
605 continue;
606 }
607 next_log_block += count_tags(journal, bh);
608 wrap(journal, next_log_block);
609 put_bh(bh);
610 continue;
611 }
612
613 /* A descriptor block: we can now write all of
614 * the data blocks. Yay, useful work is finally
615 * getting done here! */
616
617 tagp = &bh->b_data[sizeof(journal_header_t)];
618 while ((tagp - bh->b_data + tag_bytes)
619 <= journal->j_blocksize - descr_csum_size) {
620 unsigned long io_block;
621
622 memcpy(&tag, tagp, sizeof(tag));
623 flags = be16_to_cpu(tag.t_flags);
624
625 io_block = next_log_block++;
626 wrap(journal, next_log_block);
627 err = jread(&obh, journal, io_block);
628 if (err) {
629 /* Recover what we can, but
630 * report failure at the end. */
631 success = err;
632 printk(KERN_ERR
633 "JBD2: IO error %d recovering "
634 "block %ld in log\n",
635 err, io_block);
636 } else {
637 unsigned long long blocknr;
638
639 J_ASSERT(obh != NULL);
640 blocknr = read_tag_block(journal,
641 &tag);
642
643 /* If the block has been
644 * revoked, then we're all done
645 * here. */
646 if (jbd2_journal_test_revoke
647 (journal, blocknr,
648 next_commit_ID)) {
649 brelse(obh);
650 ++info->nr_revoke_hits;
651 goto skip_write;
652 }
653
654 /* Look for block corruption */
655 if (!jbd2_block_tag_csum_verify(
656 journal, &tag, (journal_block_tag3_t *)tagp,
657 obh->b_data, be32_to_cpu(tmp->h_sequence))) {
658 brelse(obh);
659 success = -EFSBADCRC;
660 printk(KERN_ERR "JBD2: Invalid "
661 "checksum recovering "
662 "data block %llu in "
663 "log\n", blocknr);
664 block_error = 1;
665 goto skip_write;
666 }
667
668 /* Find a buffer for the new
669 * data being restored */
670 nbh = __getblk(journal->j_fs_dev,
671 blocknr,
672 journal->j_blocksize);
673 if (nbh == NULL) {
674 printk(KERN_ERR
675 "JBD2: Out of memory "
676 "during recovery.\n");
677 err = -ENOMEM;
678 brelse(bh);
679 brelse(obh);
680 goto failed;
681 }
682
683 lock_buffer(nbh);
684 memcpy(nbh->b_data, obh->b_data,
685 journal->j_blocksize);
686 if (flags & JBD2_FLAG_ESCAPE) {
687 *((__be32 *)nbh->b_data) =
688 cpu_to_be32(JBD2_MAGIC_NUMBER);
689 }
690
691 BUFFER_TRACE(nbh, "marking dirty");
692 set_buffer_uptodate(nbh);
693 mark_buffer_dirty(nbh);
694 BUFFER_TRACE(nbh, "marking uptodate");
695 ++info->nr_replays;
696 unlock_buffer(nbh);
697 brelse(obh);
698 brelse(nbh);
699 }
700
701 skip_write:
702 tagp += tag_bytes;
703 if (!(flags & JBD2_FLAG_SAME_UUID))
704 tagp += 16;
705
706 if (flags & JBD2_FLAG_LAST_TAG)
707 break;
708 }
709
710 brelse(bh);
711 continue;
712
713 case JBD2_COMMIT_BLOCK:
714 /* How to differentiate between interrupted commit
715 * and journal corruption ?
716 *
717 * {nth transaction}
718 * Checksum Verification Failed
719 * |
720 * ____________________
721 * | |
722 * async_commit sync_commit
723 * | |
724 * | GO TO NEXT "Journal Corruption"
725 * | TRANSACTION
726 * |
727 * {(n+1)th transanction}
728 * |
729 * _______|______________
730 * | |
731 * Commit block found Commit block not found
732 * | |
733 * "Journal Corruption" |
734 * _____________|_________
735 * | |
736 * nth trans corrupt OR nth trans
737 * and (n+1)th interrupted interrupted
738 * before commit block
739 * could reach the disk.
740 * (Cannot find the difference in above
741 * mentioned conditions. Hence assume
742 * "Interrupted Commit".)
743 */
744 commit_time = be64_to_cpu(
745 ((struct commit_header *)bh->b_data)->h_commit_sec);
746 /*
747 * If need_check_commit_time is set, it means we are in
748 * PASS_SCAN and csum verify failed before. If
749 * commit_time is increasing, it's the same journal,
750 * otherwise it is stale journal block, just end this
751 * recovery.
752 */
753 if (need_check_commit_time) {
754 if (commit_time >= last_trans_commit_time) {
755 pr_err("JBD2: Invalid checksum found in transaction %u\n",
756 next_commit_ID);
757 err = -EFSBADCRC;
758 brelse(bh);
759 goto failed;
760 }
761 ignore_crc_mismatch:
762 /*
763 * It likely does not belong to same journal,
764 * just end this recovery with success.
765 */
766 jbd2_debug(1, "JBD2: Invalid checksum ignored in transaction %u, likely stale data\n",
767 next_commit_ID);
768 brelse(bh);
769 goto done;
770 }
771
772 /*
773 * Found an expected commit block: if checksums
774 * are present, verify them in PASS_SCAN; else not
775 * much to do other than move on to the next sequence
776 * number.
777 */
778 if (pass == PASS_SCAN &&
779 jbd2_has_feature_checksum(journal)) {
780 struct commit_header *cbh =
781 (struct commit_header *)bh->b_data;
782 unsigned found_chksum =
783 be32_to_cpu(cbh->h_chksum[0]);
784
785 if (info->end_transaction) {
786 journal->j_failed_commit =
787 info->end_transaction;
788 brelse(bh);
789 break;
790 }
791
792 /* Neither checksum match nor unused? */
793 if (!((crc32_sum == found_chksum &&
794 cbh->h_chksum_type ==
795 JBD2_CRC32_CHKSUM &&
796 cbh->h_chksum_size ==
797 JBD2_CRC32_CHKSUM_SIZE) ||
798 (cbh->h_chksum_type == 0 &&
799 cbh->h_chksum_size == 0 &&
800 found_chksum == 0)))
801 goto chksum_error;
802
803 crc32_sum = ~0;
804 }
805 if (pass == PASS_SCAN &&
806 !jbd2_commit_block_csum_verify(journal,
807 bh->b_data)) {
808 chksum_error:
809 if (commit_time < last_trans_commit_time)
810 goto ignore_crc_mismatch;
811 info->end_transaction = next_commit_ID;
812
813 if (!jbd2_has_feature_async_commit(journal)) {
814 journal->j_failed_commit =
815 next_commit_ID;
816 brelse(bh);
817 break;
818 }
819 }
820 if (pass == PASS_SCAN)
821 last_trans_commit_time = commit_time;
822 brelse(bh);
823 next_commit_ID++;
824 continue;
825
826 case JBD2_REVOKE_BLOCK:
827 /*
828 * Check revoke block crc in pass_scan, if csum verify
829 * failed, check commit block time later.
830 */
831 if (pass == PASS_SCAN &&
832 !jbd2_descriptor_block_csum_verify(journal,
833 bh->b_data)) {
834 jbd2_debug(1, "JBD2: invalid revoke block found in %lu\n",
835 next_log_block);
836 need_check_commit_time = true;
837 }
838 /* If we aren't in the REVOKE pass, then we can
839 * just skip over this block. */
840 if (pass != PASS_REVOKE) {
841 brelse(bh);
842 continue;
843 }
844
845 err = scan_revoke_records(journal, bh,
846 next_commit_ID, info);
847 brelse(bh);
848 if (err)
849 goto failed;
850 continue;
851
852 default:
853 jbd2_debug(3, "Unrecognised magic %d, end of scan.\n",
854 blocktype);
855 brelse(bh);
856 goto done;
857 }
858 }
859
860 done:
861 /*
862 * We broke out of the log scan loop: either we came to the
863 * known end of the log or we found an unexpected block in the
864 * log. If the latter happened, then we know that the "current"
865 * transaction marks the end of the valid log.
866 */
867
868 if (pass == PASS_SCAN) {
869 if (!info->end_transaction)
870 info->end_transaction = next_commit_ID;
871 } else {
872 /* It's really bad news if different passes end up at
873 * different places (but possible due to IO errors). */
874 if (info->end_transaction != next_commit_ID) {
875 printk(KERN_ERR "JBD2: recovery pass %d ended at "
876 "transaction %u, expected %u\n",
877 pass, next_commit_ID, info->end_transaction);
878 if (!success)
879 success = -EIO;
880 }
881 }
882
883 if (jbd2_has_feature_fast_commit(journal) && pass != PASS_REVOKE) {
884 err = fc_do_one_pass(journal, info, pass);
885 if (err)
886 success = err;
887 }
888
889 if (block_error && success == 0)
890 success = -EIO;
891 return success;
892
893 failed:
894 return err;
895}
896
897/* Scan a revoke record, marking all blocks mentioned as revoked. */
898
899static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
900 tid_t sequence, struct recovery_info *info)
901{
902 jbd2_journal_revoke_header_t *header;
903 int offset, max;
904 unsigned csum_size = 0;
905 __u32 rcount;
906 int record_len = 4;
907
908 header = (jbd2_journal_revoke_header_t *) bh->b_data;
909 offset = sizeof(jbd2_journal_revoke_header_t);
910 rcount = be32_to_cpu(header->r_count);
911
912 if (jbd2_journal_has_csum_v2or3(journal))
913 csum_size = sizeof(struct jbd2_journal_block_tail);
914 if (rcount > journal->j_blocksize - csum_size)
915 return -EINVAL;
916 max = rcount;
917
918 if (jbd2_has_feature_64bit(journal))
919 record_len = 8;
920
921 while (offset + record_len <= max) {
922 unsigned long long blocknr;
923 int err;
924
925 if (record_len == 4)
926 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
927 else
928 blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset)));
929 offset += record_len;
930 err = jbd2_journal_set_revoke(journal, blocknr, sequence);
931 if (err)
932 return err;
933 ++info->nr_revokes;
934 }
935 return 0;
936}
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * linux/fs/jbd2/recovery.c
4 *
5 * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
6 *
7 * Copyright 1999-2000 Red Hat Software --- All Rights Reserved
8 *
9 * Journal recovery routines for the generic filesystem journaling code;
10 * part of the ext2fs journaling system.
11 */
12
13#ifndef __KERNEL__
14#include "jfs_user.h"
15#else
16#include <linux/time.h>
17#include <linux/fs.h>
18#include <linux/jbd2.h>
19#include <linux/errno.h>
20#include <linux/crc32.h>
21#include <linux/blkdev.h>
22#endif
23
24/*
25 * Maintain information about the progress of the recovery job, so that
26 * the different passes can carry information between them.
27 */
28struct recovery_info
29{
30 tid_t start_transaction;
31 tid_t end_transaction;
32
33 int nr_replays;
34 int nr_revokes;
35 int nr_revoke_hits;
36};
37
38enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY};
39static int do_one_pass(journal_t *journal,
40 struct recovery_info *info, enum passtype pass);
41static int scan_revoke_records(journal_t *, struct buffer_head *,
42 tid_t, struct recovery_info *);
43
44#ifdef __KERNEL__
45
46/* Release readahead buffers after use */
47static void journal_brelse_array(struct buffer_head *b[], int n)
48{
49 while (--n >= 0)
50 brelse (b[n]);
51}
52
53
54/*
55 * When reading from the journal, we are going through the block device
56 * layer directly and so there is no readahead being done for us. We
57 * need to implement any readahead ourselves if we want it to happen at
58 * all. Recovery is basically one long sequential read, so make sure we
59 * do the IO in reasonably large chunks.
60 *
61 * This is not so critical that we need to be enormously clever about
62 * the readahead size, though. 128K is a purely arbitrary, good-enough
63 * fixed value.
64 */
65
66#define MAXBUF 8
67static int do_readahead(journal_t *journal, unsigned int start)
68{
69 int err;
70 unsigned int max, nbufs, next;
71 unsigned long long blocknr;
72 struct buffer_head *bh;
73
74 struct buffer_head * bufs[MAXBUF];
75
76 /* Do up to 128K of readahead */
77 max = start + (128 * 1024 / journal->j_blocksize);
78 if (max > journal->j_maxlen)
79 max = journal->j_maxlen;
80
81 /* Do the readahead itself. We'll submit MAXBUF buffer_heads at
82 * a time to the block device IO layer. */
83
84 nbufs = 0;
85
86 for (next = start; next < max; next++) {
87 err = jbd2_journal_bmap(journal, next, &blocknr);
88
89 if (err) {
90 printk(KERN_ERR "JBD2: bad block at offset %u\n",
91 next);
92 goto failed;
93 }
94
95 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
96 if (!bh) {
97 err = -ENOMEM;
98 goto failed;
99 }
100
101 if (!buffer_uptodate(bh) && !buffer_locked(bh)) {
102 bufs[nbufs++] = bh;
103 if (nbufs == MAXBUF) {
104 ll_rw_block(REQ_OP_READ, 0, nbufs, bufs);
105 journal_brelse_array(bufs, nbufs);
106 nbufs = 0;
107 }
108 } else
109 brelse(bh);
110 }
111
112 if (nbufs)
113 ll_rw_block(REQ_OP_READ, 0, nbufs, bufs);
114 err = 0;
115
116failed:
117 if (nbufs)
118 journal_brelse_array(bufs, nbufs);
119 return err;
120}
121
122#endif /* __KERNEL__ */
123
124
125/*
126 * Read a block from the journal
127 */
128
129static int jread(struct buffer_head **bhp, journal_t *journal,
130 unsigned int offset)
131{
132 int err;
133 unsigned long long blocknr;
134 struct buffer_head *bh;
135
136 *bhp = NULL;
137
138 if (offset >= journal->j_maxlen) {
139 printk(KERN_ERR "JBD2: corrupted journal superblock\n");
140 return -EFSCORRUPTED;
141 }
142
143 err = jbd2_journal_bmap(journal, offset, &blocknr);
144
145 if (err) {
146 printk(KERN_ERR "JBD2: bad block at offset %u\n",
147 offset);
148 return err;
149 }
150
151 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
152 if (!bh)
153 return -ENOMEM;
154
155 if (!buffer_uptodate(bh)) {
156 /* If this is a brand new buffer, start readahead.
157 Otherwise, we assume we are already reading it. */
158 if (!buffer_req(bh))
159 do_readahead(journal, offset);
160 wait_on_buffer(bh);
161 }
162
163 if (!buffer_uptodate(bh)) {
164 printk(KERN_ERR "JBD2: Failed to read block at offset %u\n",
165 offset);
166 brelse(bh);
167 return -EIO;
168 }
169
170 *bhp = bh;
171 return 0;
172}
173
174static int jbd2_descriptor_block_csum_verify(journal_t *j, void *buf)
175{
176 struct jbd2_journal_block_tail *tail;
177 __be32 provided;
178 __u32 calculated;
179
180 if (!jbd2_journal_has_csum_v2or3(j))
181 return 1;
182
183 tail = (struct jbd2_journal_block_tail *)(buf + j->j_blocksize -
184 sizeof(struct jbd2_journal_block_tail));
185 provided = tail->t_checksum;
186 tail->t_checksum = 0;
187 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
188 tail->t_checksum = provided;
189
190 return provided == cpu_to_be32(calculated);
191}
192
193/*
194 * Count the number of in-use tags in a journal descriptor block.
195 */
196
197static int count_tags(journal_t *journal, struct buffer_head *bh)
198{
199 char * tagp;
200 journal_block_tag_t * tag;
201 int nr = 0, size = journal->j_blocksize;
202 int tag_bytes = journal_tag_bytes(journal);
203
204 if (jbd2_journal_has_csum_v2or3(journal))
205 size -= sizeof(struct jbd2_journal_block_tail);
206
207 tagp = &bh->b_data[sizeof(journal_header_t)];
208
209 while ((tagp - bh->b_data + tag_bytes) <= size) {
210 tag = (journal_block_tag_t *) tagp;
211
212 nr++;
213 tagp += tag_bytes;
214 if (!(tag->t_flags & cpu_to_be16(JBD2_FLAG_SAME_UUID)))
215 tagp += 16;
216
217 if (tag->t_flags & cpu_to_be16(JBD2_FLAG_LAST_TAG))
218 break;
219 }
220
221 return nr;
222}
223
224
225/* Make sure we wrap around the log correctly! */
226#define wrap(journal, var) \
227do { \
228 if (var >= (journal)->j_last) \
229 var -= ((journal)->j_last - (journal)->j_first); \
230} while (0)
231
232/**
233 * jbd2_journal_recover - recovers a on-disk journal
234 * @journal: the journal to recover
235 *
236 * The primary function for recovering the log contents when mounting a
237 * journaled device.
238 *
239 * Recovery is done in three passes. In the first pass, we look for the
240 * end of the log. In the second, we assemble the list of revoke
241 * blocks. In the third and final pass, we replay any un-revoked blocks
242 * in the log.
243 */
244int jbd2_journal_recover(journal_t *journal)
245{
246 int err, err2;
247 journal_superblock_t * sb;
248
249 struct recovery_info info;
250
251 memset(&info, 0, sizeof(info));
252 sb = journal->j_superblock;
253
254 /*
255 * The journal superblock's s_start field (the current log head)
256 * is always zero if, and only if, the journal was cleanly
257 * unmounted.
258 */
259
260 if (!sb->s_start) {
261 jbd_debug(1, "No recovery required, last transaction %d\n",
262 be32_to_cpu(sb->s_sequence));
263 journal->j_transaction_sequence = be32_to_cpu(sb->s_sequence) + 1;
264 return 0;
265 }
266
267 err = do_one_pass(journal, &info, PASS_SCAN);
268 if (!err)
269 err = do_one_pass(journal, &info, PASS_REVOKE);
270 if (!err)
271 err = do_one_pass(journal, &info, PASS_REPLAY);
272
273 jbd_debug(1, "JBD2: recovery, exit status %d, "
274 "recovered transactions %u to %u\n",
275 err, info.start_transaction, info.end_transaction);
276 jbd_debug(1, "JBD2: Replayed %d and revoked %d/%d blocks\n",
277 info.nr_replays, info.nr_revoke_hits, info.nr_revokes);
278
279 /* Restart the log at the next transaction ID, thus invalidating
280 * any existing commit records in the log. */
281 journal->j_transaction_sequence = ++info.end_transaction;
282
283 jbd2_journal_clear_revoke(journal);
284 err2 = sync_blockdev(journal->j_fs_dev);
285 if (!err)
286 err = err2;
287 /* Make sure all replayed data is on permanent storage */
288 if (journal->j_flags & JBD2_BARRIER) {
289 err2 = blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL);
290 if (!err)
291 err = err2;
292 }
293 return err;
294}
295
296/**
297 * jbd2_journal_skip_recovery - Start journal and wipe exiting records
298 * @journal: journal to startup
299 *
300 * Locate any valid recovery information from the journal and set up the
301 * journal structures in memory to ignore it (presumably because the
302 * caller has evidence that it is out of date).
303 * This function doesn't appear to be exported..
304 *
305 * We perform one pass over the journal to allow us to tell the user how
306 * much recovery information is being erased, and to let us initialise
307 * the journal transaction sequence numbers to the next unused ID.
308 */
309int jbd2_journal_skip_recovery(journal_t *journal)
310{
311 int err;
312
313 struct recovery_info info;
314
315 memset (&info, 0, sizeof(info));
316
317 err = do_one_pass(journal, &info, PASS_SCAN);
318
319 if (err) {
320 printk(KERN_ERR "JBD2: error %d scanning journal\n", err);
321 ++journal->j_transaction_sequence;
322 } else {
323#ifdef CONFIG_JBD2_DEBUG
324 int dropped = info.end_transaction -
325 be32_to_cpu(journal->j_superblock->s_sequence);
326 jbd_debug(1,
327 "JBD2: ignoring %d transaction%s from the journal.\n",
328 dropped, (dropped == 1) ? "" : "s");
329#endif
330 journal->j_transaction_sequence = ++info.end_transaction;
331 }
332
333 journal->j_tail = 0;
334 return err;
335}
336
337static inline unsigned long long read_tag_block(journal_t *journal,
338 journal_block_tag_t *tag)
339{
340 unsigned long long block = be32_to_cpu(tag->t_blocknr);
341 if (jbd2_has_feature_64bit(journal))
342 block |= (u64)be32_to_cpu(tag->t_blocknr_high) << 32;
343 return block;
344}
345
346/*
347 * calc_chksums calculates the checksums for the blocks described in the
348 * descriptor block.
349 */
350static int calc_chksums(journal_t *journal, struct buffer_head *bh,
351 unsigned long *next_log_block, __u32 *crc32_sum)
352{
353 int i, num_blks, err;
354 unsigned long io_block;
355 struct buffer_head *obh;
356
357 num_blks = count_tags(journal, bh);
358 /* Calculate checksum of the descriptor block. */
359 *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size);
360
361 for (i = 0; i < num_blks; i++) {
362 io_block = (*next_log_block)++;
363 wrap(journal, *next_log_block);
364 err = jread(&obh, journal, io_block);
365 if (err) {
366 printk(KERN_ERR "JBD2: IO error %d recovering block "
367 "%lu in log\n", err, io_block);
368 return 1;
369 } else {
370 *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data,
371 obh->b_size);
372 }
373 put_bh(obh);
374 }
375 return 0;
376}
377
378static int jbd2_commit_block_csum_verify(journal_t *j, void *buf)
379{
380 struct commit_header *h;
381 __be32 provided;
382 __u32 calculated;
383
384 if (!jbd2_journal_has_csum_v2or3(j))
385 return 1;
386
387 h = buf;
388 provided = h->h_chksum[0];
389 h->h_chksum[0] = 0;
390 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
391 h->h_chksum[0] = provided;
392
393 return provided == cpu_to_be32(calculated);
394}
395
396static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag,
397 void *buf, __u32 sequence)
398{
399 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
400 __u32 csum32;
401 __be32 seq;
402
403 if (!jbd2_journal_has_csum_v2or3(j))
404 return 1;
405
406 seq = cpu_to_be32(sequence);
407 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
408 csum32 = jbd2_chksum(j, csum32, buf, j->j_blocksize);
409
410 if (jbd2_has_feature_csum3(j))
411 return tag3->t_checksum == cpu_to_be32(csum32);
412 else
413 return tag->t_checksum == cpu_to_be16(csum32);
414}
415
416static int do_one_pass(journal_t *journal,
417 struct recovery_info *info, enum passtype pass)
418{
419 unsigned int first_commit_ID, next_commit_ID;
420 unsigned long next_log_block;
421 int err, success = 0;
422 journal_superblock_t * sb;
423 journal_header_t * tmp;
424 struct buffer_head * bh;
425 unsigned int sequence;
426 int blocktype;
427 int tag_bytes = journal_tag_bytes(journal);
428 __u32 crc32_sum = ~0; /* Transactional Checksums */
429 int descr_csum_size = 0;
430 int block_error = 0;
431
432 /*
433 * First thing is to establish what we expect to find in the log
434 * (in terms of transaction IDs), and where (in terms of log
435 * block offsets): query the superblock.
436 */
437
438 sb = journal->j_superblock;
439 next_commit_ID = be32_to_cpu(sb->s_sequence);
440 next_log_block = be32_to_cpu(sb->s_start);
441
442 first_commit_ID = next_commit_ID;
443 if (pass == PASS_SCAN)
444 info->start_transaction = first_commit_ID;
445
446 jbd_debug(1, "Starting recovery pass %d\n", pass);
447
448 /*
449 * Now we walk through the log, transaction by transaction,
450 * making sure that each transaction has a commit block in the
451 * expected place. Each complete transaction gets replayed back
452 * into the main filesystem.
453 */
454
455 while (1) {
456 int flags;
457 char * tagp;
458 journal_block_tag_t * tag;
459 struct buffer_head * obh;
460 struct buffer_head * nbh;
461
462 cond_resched();
463
464 /* If we already know where to stop the log traversal,
465 * check right now that we haven't gone past the end of
466 * the log. */
467
468 if (pass != PASS_SCAN)
469 if (tid_geq(next_commit_ID, info->end_transaction))
470 break;
471
472 jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
473 next_commit_ID, next_log_block, journal->j_last);
474
475 /* Skip over each chunk of the transaction looking
476 * either the next descriptor block or the final commit
477 * record. */
478
479 jbd_debug(3, "JBD2: checking block %ld\n", next_log_block);
480 err = jread(&bh, journal, next_log_block);
481 if (err)
482 goto failed;
483
484 next_log_block++;
485 wrap(journal, next_log_block);
486
487 /* What kind of buffer is it?
488 *
489 * If it is a descriptor block, check that it has the
490 * expected sequence number. Otherwise, we're all done
491 * here. */
492
493 tmp = (journal_header_t *)bh->b_data;
494
495 if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) {
496 brelse(bh);
497 break;
498 }
499
500 blocktype = be32_to_cpu(tmp->h_blocktype);
501 sequence = be32_to_cpu(tmp->h_sequence);
502 jbd_debug(3, "Found magic %d, sequence %d\n",
503 blocktype, sequence);
504
505 if (sequence != next_commit_ID) {
506 brelse(bh);
507 break;
508 }
509
510 /* OK, we have a valid descriptor block which matches
511 * all of the sequence number checks. What are we going
512 * to do with it? That depends on the pass... */
513
514 switch(blocktype) {
515 case JBD2_DESCRIPTOR_BLOCK:
516 /* Verify checksum first */
517 if (jbd2_journal_has_csum_v2or3(journal))
518 descr_csum_size =
519 sizeof(struct jbd2_journal_block_tail);
520 if (descr_csum_size > 0 &&
521 !jbd2_descriptor_block_csum_verify(journal,
522 bh->b_data)) {
523 printk(KERN_ERR "JBD2: Invalid checksum "
524 "recovering block %lu in log\n",
525 next_log_block);
526 err = -EFSBADCRC;
527 brelse(bh);
528 goto failed;
529 }
530
531 /* If it is a valid descriptor block, replay it
532 * in pass REPLAY; if journal_checksums enabled, then
533 * calculate checksums in PASS_SCAN, otherwise,
534 * just skip over the blocks it describes. */
535 if (pass != PASS_REPLAY) {
536 if (pass == PASS_SCAN &&
537 jbd2_has_feature_checksum(journal) &&
538 !info->end_transaction) {
539 if (calc_chksums(journal, bh,
540 &next_log_block,
541 &crc32_sum)) {
542 put_bh(bh);
543 break;
544 }
545 put_bh(bh);
546 continue;
547 }
548 next_log_block += count_tags(journal, bh);
549 wrap(journal, next_log_block);
550 put_bh(bh);
551 continue;
552 }
553
554 /* A descriptor block: we can now write all of
555 * the data blocks. Yay, useful work is finally
556 * getting done here! */
557
558 tagp = &bh->b_data[sizeof(journal_header_t)];
559 while ((tagp - bh->b_data + tag_bytes)
560 <= journal->j_blocksize - descr_csum_size) {
561 unsigned long io_block;
562
563 tag = (journal_block_tag_t *) tagp;
564 flags = be16_to_cpu(tag->t_flags);
565
566 io_block = next_log_block++;
567 wrap(journal, next_log_block);
568 err = jread(&obh, journal, io_block);
569 if (err) {
570 /* Recover what we can, but
571 * report failure at the end. */
572 success = err;
573 printk(KERN_ERR
574 "JBD2: IO error %d recovering "
575 "block %ld in log\n",
576 err, io_block);
577 } else {
578 unsigned long long blocknr;
579
580 J_ASSERT(obh != NULL);
581 blocknr = read_tag_block(journal,
582 tag);
583
584 /* If the block has been
585 * revoked, then we're all done
586 * here. */
587 if (jbd2_journal_test_revoke
588 (journal, blocknr,
589 next_commit_ID)) {
590 brelse(obh);
591 ++info->nr_revoke_hits;
592 goto skip_write;
593 }
594
595 /* Look for block corruption */
596 if (!jbd2_block_tag_csum_verify(
597 journal, tag, obh->b_data,
598 be32_to_cpu(tmp->h_sequence))) {
599 brelse(obh);
600 success = -EFSBADCRC;
601 printk(KERN_ERR "JBD2: Invalid "
602 "checksum recovering "
603 "data block %llu in "
604 "log\n", blocknr);
605 block_error = 1;
606 goto skip_write;
607 }
608
609 /* Find a buffer for the new
610 * data being restored */
611 nbh = __getblk(journal->j_fs_dev,
612 blocknr,
613 journal->j_blocksize);
614 if (nbh == NULL) {
615 printk(KERN_ERR
616 "JBD2: Out of memory "
617 "during recovery.\n");
618 err = -ENOMEM;
619 brelse(bh);
620 brelse(obh);
621 goto failed;
622 }
623
624 lock_buffer(nbh);
625 memcpy(nbh->b_data, obh->b_data,
626 journal->j_blocksize);
627 if (flags & JBD2_FLAG_ESCAPE) {
628 *((__be32 *)nbh->b_data) =
629 cpu_to_be32(JBD2_MAGIC_NUMBER);
630 }
631
632 BUFFER_TRACE(nbh, "marking dirty");
633 set_buffer_uptodate(nbh);
634 mark_buffer_dirty(nbh);
635 BUFFER_TRACE(nbh, "marking uptodate");
636 ++info->nr_replays;
637 /* ll_rw_block(WRITE, 1, &nbh); */
638 unlock_buffer(nbh);
639 brelse(obh);
640 brelse(nbh);
641 }
642
643 skip_write:
644 tagp += tag_bytes;
645 if (!(flags & JBD2_FLAG_SAME_UUID))
646 tagp += 16;
647
648 if (flags & JBD2_FLAG_LAST_TAG)
649 break;
650 }
651
652 brelse(bh);
653 continue;
654
655 case JBD2_COMMIT_BLOCK:
656 /* How to differentiate between interrupted commit
657 * and journal corruption ?
658 *
659 * {nth transaction}
660 * Checksum Verification Failed
661 * |
662 * ____________________
663 * | |
664 * async_commit sync_commit
665 * | |
666 * | GO TO NEXT "Journal Corruption"
667 * | TRANSACTION
668 * |
669 * {(n+1)th transanction}
670 * |
671 * _______|______________
672 * | |
673 * Commit block found Commit block not found
674 * | |
675 * "Journal Corruption" |
676 * _____________|_________
677 * | |
678 * nth trans corrupt OR nth trans
679 * and (n+1)th interrupted interrupted
680 * before commit block
681 * could reach the disk.
682 * (Cannot find the difference in above
683 * mentioned conditions. Hence assume
684 * "Interrupted Commit".)
685 */
686
687 /* Found an expected commit block: if checksums
688 * are present verify them in PASS_SCAN; else not
689 * much to do other than move on to the next sequence
690 * number. */
691 if (pass == PASS_SCAN &&
692 jbd2_has_feature_checksum(journal)) {
693 struct commit_header *cbh =
694 (struct commit_header *)bh->b_data;
695 unsigned found_chksum =
696 be32_to_cpu(cbh->h_chksum[0]);
697
698 if (info->end_transaction) {
699 journal->j_failed_commit =
700 info->end_transaction;
701 brelse(bh);
702 break;
703 }
704
705 /* Neither checksum match nor unused? */
706 if (!((crc32_sum == found_chksum &&
707 cbh->h_chksum_type ==
708 JBD2_CRC32_CHKSUM &&
709 cbh->h_chksum_size ==
710 JBD2_CRC32_CHKSUM_SIZE) ||
711 (cbh->h_chksum_type == 0 &&
712 cbh->h_chksum_size == 0 &&
713 found_chksum == 0)))
714 goto chksum_error;
715
716 crc32_sum = ~0;
717 }
718 if (pass == PASS_SCAN &&
719 !jbd2_commit_block_csum_verify(journal,
720 bh->b_data)) {
721 chksum_error:
722 info->end_transaction = next_commit_ID;
723
724 if (!jbd2_has_feature_async_commit(journal)) {
725 journal->j_failed_commit =
726 next_commit_ID;
727 brelse(bh);
728 break;
729 }
730 }
731 brelse(bh);
732 next_commit_ID++;
733 continue;
734
735 case JBD2_REVOKE_BLOCK:
736 /* If we aren't in the REVOKE pass, then we can
737 * just skip over this block. */
738 if (pass != PASS_REVOKE) {
739 brelse(bh);
740 continue;
741 }
742
743 err = scan_revoke_records(journal, bh,
744 next_commit_ID, info);
745 brelse(bh);
746 if (err)
747 goto failed;
748 continue;
749
750 default:
751 jbd_debug(3, "Unrecognised magic %d, end of scan.\n",
752 blocktype);
753 brelse(bh);
754 goto done;
755 }
756 }
757
758 done:
759 /*
760 * We broke out of the log scan loop: either we came to the
761 * known end of the log or we found an unexpected block in the
762 * log. If the latter happened, then we know that the "current"
763 * transaction marks the end of the valid log.
764 */
765
766 if (pass == PASS_SCAN) {
767 if (!info->end_transaction)
768 info->end_transaction = next_commit_ID;
769 } else {
770 /* It's really bad news if different passes end up at
771 * different places (but possible due to IO errors). */
772 if (info->end_transaction != next_commit_ID) {
773 printk(KERN_ERR "JBD2: recovery pass %d ended at "
774 "transaction %u, expected %u\n",
775 pass, next_commit_ID, info->end_transaction);
776 if (!success)
777 success = -EIO;
778 }
779 }
780 if (block_error && success == 0)
781 success = -EIO;
782 return success;
783
784 failed:
785 return err;
786}
787
788/* Scan a revoke record, marking all blocks mentioned as revoked. */
789
790static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
791 tid_t sequence, struct recovery_info *info)
792{
793 jbd2_journal_revoke_header_t *header;
794 int offset, max;
795 int csum_size = 0;
796 __u32 rcount;
797 int record_len = 4;
798
799 header = (jbd2_journal_revoke_header_t *) bh->b_data;
800 offset = sizeof(jbd2_journal_revoke_header_t);
801 rcount = be32_to_cpu(header->r_count);
802
803 if (!jbd2_descriptor_block_csum_verify(journal, header))
804 return -EFSBADCRC;
805
806 if (jbd2_journal_has_csum_v2or3(journal))
807 csum_size = sizeof(struct jbd2_journal_block_tail);
808 if (rcount > journal->j_blocksize - csum_size)
809 return -EINVAL;
810 max = rcount;
811
812 if (jbd2_has_feature_64bit(journal))
813 record_len = 8;
814
815 while (offset + record_len <= max) {
816 unsigned long long blocknr;
817 int err;
818
819 if (record_len == 4)
820 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
821 else
822 blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset)));
823 offset += record_len;
824 err = jbd2_journal_set_revoke(journal, blocknr, sequence);
825 if (err)
826 return err;
827 ++info->nr_revokes;
828 }
829 return 0;
830}