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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/*
2 * linux/fs/jbd2/recovery.c
3 *
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
5 *
6 * Copyright 1999-2000 Red Hat Software --- All Rights Reserved
7 *
8 * This file is part of the Linux kernel and is made available under
9 * the terms of the GNU General Public License, version 2, or at your
10 * option, any later version, incorporated herein by reference.
11 *
12 * Journal recovery routines for the generic filesystem journaling code;
13 * part of the ext2fs journaling system.
14 */
15
16#ifndef __KERNEL__
17#include "jfs_user.h"
18#else
19#include <linux/time.h>
20#include <linux/fs.h>
21#include <linux/jbd2.h>
22#include <linux/errno.h>
23#include <linux/crc32.h>
24#include <linux/blkdev.h>
25#endif
26
27/*
28 * Maintain information about the progress of the recovery job, so that
29 * the different passes can carry information between them.
30 */
31struct recovery_info
32{
33 tid_t start_transaction;
34 tid_t end_transaction;
35
36 int nr_replays;
37 int nr_revokes;
38 int nr_revoke_hits;
39};
40
41enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY};
42static int do_one_pass(journal_t *journal,
43 struct recovery_info *info, enum passtype pass);
44static int scan_revoke_records(journal_t *, struct buffer_head *,
45 tid_t, struct recovery_info *);
46
47#ifdef __KERNEL__
48
49/* Release readahead buffers after use */
50static void journal_brelse_array(struct buffer_head *b[], int n)
51{
52 while (--n >= 0)
53 brelse (b[n]);
54}
55
56
57/*
58 * When reading from the journal, we are going through the block device
59 * layer directly and so there is no readahead being done for us. We
60 * need to implement any readahead ourselves if we want it to happen at
61 * all. Recovery is basically one long sequential read, so make sure we
62 * do the IO in reasonably large chunks.
63 *
64 * This is not so critical that we need to be enormously clever about
65 * the readahead size, though. 128K is a purely arbitrary, good-enough
66 * fixed value.
67 */
68
69#define MAXBUF 8
70static int do_readahead(journal_t *journal, unsigned int start)
71{
72 int err;
73 unsigned int max, nbufs, next;
74 unsigned long long blocknr;
75 struct buffer_head *bh;
76
77 struct buffer_head * bufs[MAXBUF];
78
79 /* Do up to 128K of readahead */
80 max = start + (128 * 1024 / journal->j_blocksize);
81 if (max > journal->j_maxlen)
82 max = journal->j_maxlen;
83
84 /* Do the readahead itself. We'll submit MAXBUF buffer_heads at
85 * a time to the block device IO layer. */
86
87 nbufs = 0;
88
89 for (next = start; next < max; next++) {
90 err = jbd2_journal_bmap(journal, next, &blocknr);
91
92 if (err) {
93 printk(KERN_ERR "JBD2: bad block at offset %u\n",
94 next);
95 goto failed;
96 }
97
98 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
99 if (!bh) {
100 err = -ENOMEM;
101 goto failed;
102 }
103
104 if (!buffer_uptodate(bh) && !buffer_locked(bh)) {
105 bufs[nbufs++] = bh;
106 if (nbufs == MAXBUF) {
107 ll_rw_block(READ, nbufs, bufs);
108 journal_brelse_array(bufs, nbufs);
109 nbufs = 0;
110 }
111 } else
112 brelse(bh);
113 }
114
115 if (nbufs)
116 ll_rw_block(READ, nbufs, bufs);
117 err = 0;
118
119failed:
120 if (nbufs)
121 journal_brelse_array(bufs, nbufs);
122 return err;
123}
124
125#endif /* __KERNEL__ */
126
127
128/*
129 * Read a block from the journal
130 */
131
132static int jread(struct buffer_head **bhp, journal_t *journal,
133 unsigned int offset)
134{
135 int err;
136 unsigned long long blocknr;
137 struct buffer_head *bh;
138
139 *bhp = NULL;
140
141 if (offset >= journal->j_maxlen) {
142 printk(KERN_ERR "JBD2: corrupted journal superblock\n");
143 return -EIO;
144 }
145
146 err = jbd2_journal_bmap(journal, offset, &blocknr);
147
148 if (err) {
149 printk(KERN_ERR "JBD2: bad block at offset %u\n",
150 offset);
151 return err;
152 }
153
154 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
155 if (!bh)
156 return -ENOMEM;
157
158 if (!buffer_uptodate(bh)) {
159 /* If this is a brand new buffer, start readahead.
160 Otherwise, we assume we are already reading it. */
161 if (!buffer_req(bh))
162 do_readahead(journal, offset);
163 wait_on_buffer(bh);
164 }
165
166 if (!buffer_uptodate(bh)) {
167 printk(KERN_ERR "JBD2: Failed to read block at offset %u\n",
168 offset);
169 brelse(bh);
170 return -EIO;
171 }
172
173 *bhp = bh;
174 return 0;
175}
176
177static int jbd2_descr_block_csum_verify(journal_t *j,
178 void *buf)
179{
180 struct jbd2_journal_block_tail *tail;
181 __u32 provided, calculated;
182
183 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
184 return 1;
185
186 tail = (struct jbd2_journal_block_tail *)(buf + j->j_blocksize -
187 sizeof(struct jbd2_journal_block_tail));
188 provided = tail->t_checksum;
189 tail->t_checksum = 0;
190 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
191 tail->t_checksum = provided;
192
193 provided = be32_to_cpu(provided);
194 return provided == 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_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
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 tag = (journal_block_tag_t *) tagp;
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 if (var >= (journal)->j_last) \
233 var -= ((journal)->j_last - (journal)->j_first); \
234} while (0)
235
236/**
237 * jbd2_journal_recover - recovers a on-disk journal
238 * @journal: the journal to recover
239 *
240 * The primary function for recovering the log contents when mounting a
241 * journaled device.
242 *
243 * Recovery is done in three passes. In the first pass, we look for the
244 * end of the log. In the second, we assemble the list of revoke
245 * blocks. In the third and final pass, we replay any un-revoked blocks
246 * in the log.
247 */
248int jbd2_journal_recover(journal_t *journal)
249{
250 int err, err2;
251 journal_superblock_t * sb;
252
253 struct recovery_info info;
254
255 memset(&info, 0, sizeof(info));
256 sb = journal->j_superblock;
257
258 /*
259 * The journal superblock's s_start field (the current log head)
260 * is always zero if, and only if, the journal was cleanly
261 * unmounted.
262 */
263
264 if (!sb->s_start) {
265 jbd_debug(1, "No recovery required, last transaction %d\n",
266 be32_to_cpu(sb->s_sequence));
267 journal->j_transaction_sequence = be32_to_cpu(sb->s_sequence) + 1;
268 return 0;
269 }
270
271 err = do_one_pass(journal, &info, PASS_SCAN);
272 if (!err)
273 err = do_one_pass(journal, &info, PASS_REVOKE);
274 if (!err)
275 err = do_one_pass(journal, &info, PASS_REPLAY);
276
277 jbd_debug(1, "JBD2: recovery, exit status %d, "
278 "recovered transactions %u to %u\n",
279 err, info.start_transaction, info.end_transaction);
280 jbd_debug(1, "JBD2: Replayed %d and revoked %d/%d blocks\n",
281 info.nr_replays, info.nr_revoke_hits, info.nr_revokes);
282
283 /* Restart the log at the next transaction ID, thus invalidating
284 * any existing commit records in the log. */
285 journal->j_transaction_sequence = ++info.end_transaction;
286
287 jbd2_journal_clear_revoke(journal);
288 err2 = sync_blockdev(journal->j_fs_dev);
289 if (!err)
290 err = err2;
291 /* Make sure all replayed data is on permanent storage */
292 if (journal->j_flags & JBD2_BARRIER)
293 blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
294 return err;
295}
296
297/**
298 * jbd2_journal_skip_recovery - Start journal and wipe exiting records
299 * @journal: journal to startup
300 *
301 * Locate any valid recovery information from the journal and set up the
302 * journal structures in memory to ignore it (presumably because the
303 * caller has evidence that it is out of date).
304 * This function does'nt appear to be exorted..
305 *
306 * We perform one pass over the journal to allow us to tell the user how
307 * much recovery information is being erased, and to let us initialise
308 * the journal transaction sequence numbers to the next unused ID.
309 */
310int jbd2_journal_skip_recovery(journal_t *journal)
311{
312 int err;
313
314 struct recovery_info info;
315
316 memset (&info, 0, sizeof(info));
317
318 err = do_one_pass(journal, &info, PASS_SCAN);
319
320 if (err) {
321 printk(KERN_ERR "JBD2: error %d scanning journal\n", err);
322 ++journal->j_transaction_sequence;
323 } else {
324#ifdef CONFIG_JBD2_DEBUG
325 int dropped = info.end_transaction -
326 be32_to_cpu(journal->j_superblock->s_sequence);
327 jbd_debug(1,
328 "JBD2: ignoring %d transaction%s from the journal.\n",
329 dropped, (dropped == 1) ? "" : "s");
330#endif
331 journal->j_transaction_sequence = ++info.end_transaction;
332 }
333
334 journal->j_tail = 0;
335 return err;
336}
337
338static inline unsigned long long read_tag_block(int tag_bytes, journal_block_tag_t *tag)
339{
340 unsigned long long block = be32_to_cpu(tag->t_blocknr);
341 if (tag_bytes > JBD2_TAG_SIZE32)
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 __u32 provided, calculated;
382
383 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
384 return 1;
385
386 h = buf;
387 provided = h->h_chksum[0];
388 h->h_chksum[0] = 0;
389 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
390 h->h_chksum[0] = provided;
391
392 provided = be32_to_cpu(provided);
393 return provided == 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 __u32 provided, calculated;
400
401 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
402 return 1;
403
404 sequence = cpu_to_be32(sequence);
405 calculated = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&sequence,
406 sizeof(sequence));
407 calculated = jbd2_chksum(j, calculated, buf, j->j_blocksize);
408 provided = be32_to_cpu(tag->t_checksum);
409
410 return provided == cpu_to_be32(calculated);
411}
412
413static int do_one_pass(journal_t *journal,
414 struct recovery_info *info, enum passtype pass)
415{
416 unsigned int first_commit_ID, next_commit_ID;
417 unsigned long next_log_block;
418 int err, success = 0;
419 journal_superblock_t * sb;
420 journal_header_t * tmp;
421 struct buffer_head * bh;
422 unsigned int sequence;
423 int blocktype;
424 int tag_bytes = journal_tag_bytes(journal);
425 __u32 crc32_sum = ~0; /* Transactional Checksums */
426 int descr_csum_size = 0;
427
428 /*
429 * First thing is to establish what we expect to find in the log
430 * (in terms of transaction IDs), and where (in terms of log
431 * block offsets): query the superblock.
432 */
433
434 sb = journal->j_superblock;
435 next_commit_ID = be32_to_cpu(sb->s_sequence);
436 next_log_block = be32_to_cpu(sb->s_start);
437
438 first_commit_ID = next_commit_ID;
439 if (pass == PASS_SCAN)
440 info->start_transaction = first_commit_ID;
441
442 jbd_debug(1, "Starting recovery pass %d\n", pass);
443
444 /*
445 * Now we walk through the log, transaction by transaction,
446 * making sure that each transaction has a commit block in the
447 * expected place. Each complete transaction gets replayed back
448 * into the main filesystem.
449 */
450
451 while (1) {
452 int flags;
453 char * tagp;
454 journal_block_tag_t * tag;
455 struct buffer_head * obh;
456 struct buffer_head * nbh;
457
458 cond_resched();
459
460 /* If we already know where to stop the log traversal,
461 * check right now that we haven't gone past the end of
462 * the log. */
463
464 if (pass != PASS_SCAN)
465 if (tid_geq(next_commit_ID, info->end_transaction))
466 break;
467
468 jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
469 next_commit_ID, next_log_block, journal->j_last);
470
471 /* Skip over each chunk of the transaction looking
472 * either the next descriptor block or the final commit
473 * record. */
474
475 jbd_debug(3, "JBD2: checking block %ld\n", next_log_block);
476 err = jread(&bh, journal, next_log_block);
477 if (err)
478 goto failed;
479
480 next_log_block++;
481 wrap(journal, next_log_block);
482
483 /* What kind of buffer is it?
484 *
485 * If it is a descriptor block, check that it has the
486 * expected sequence number. Otherwise, we're all done
487 * here. */
488
489 tmp = (journal_header_t *)bh->b_data;
490
491 if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) {
492 brelse(bh);
493 break;
494 }
495
496 blocktype = be32_to_cpu(tmp->h_blocktype);
497 sequence = be32_to_cpu(tmp->h_sequence);
498 jbd_debug(3, "Found magic %d, sequence %d\n",
499 blocktype, sequence);
500
501 if (sequence != next_commit_ID) {
502 brelse(bh);
503 break;
504 }
505
506 /* OK, we have a valid descriptor block which matches
507 * all of the sequence number checks. What are we going
508 * to do with it? That depends on the pass... */
509
510 switch(blocktype) {
511 case JBD2_DESCRIPTOR_BLOCK:
512 /* Verify checksum first */
513 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
514 JBD2_FEATURE_INCOMPAT_CSUM_V2))
515 descr_csum_size =
516 sizeof(struct jbd2_journal_block_tail);
517 if (descr_csum_size > 0 &&
518 !jbd2_descr_block_csum_verify(journal,
519 bh->b_data)) {
520 err = -EIO;
521 goto failed;
522 }
523
524 /* If it is a valid descriptor block, replay it
525 * in pass REPLAY; if journal_checksums enabled, then
526 * calculate checksums in PASS_SCAN, otherwise,
527 * just skip over the blocks it describes. */
528 if (pass != PASS_REPLAY) {
529 if (pass == PASS_SCAN &&
530 JBD2_HAS_COMPAT_FEATURE(journal,
531 JBD2_FEATURE_COMPAT_CHECKSUM) &&
532 !info->end_transaction) {
533 if (calc_chksums(journal, bh,
534 &next_log_block,
535 &crc32_sum)) {
536 put_bh(bh);
537 break;
538 }
539 put_bh(bh);
540 continue;
541 }
542 next_log_block += count_tags(journal, bh);
543 wrap(journal, next_log_block);
544 put_bh(bh);
545 continue;
546 }
547
548 /* A descriptor block: we can now write all of
549 * the data blocks. Yay, useful work is finally
550 * getting done here! */
551
552 tagp = &bh->b_data[sizeof(journal_header_t)];
553 while ((tagp - bh->b_data + tag_bytes)
554 <= journal->j_blocksize - descr_csum_size) {
555 unsigned long io_block;
556
557 tag = (journal_block_tag_t *) tagp;
558 flags = be16_to_cpu(tag->t_flags);
559
560 io_block = next_log_block++;
561 wrap(journal, next_log_block);
562 err = jread(&obh, journal, io_block);
563 if (err) {
564 /* Recover what we can, but
565 * report failure at the end. */
566 success = err;
567 printk(KERN_ERR
568 "JBD2: IO error %d recovering "
569 "block %ld in log\n",
570 err, io_block);
571 } else {
572 unsigned long long blocknr;
573
574 J_ASSERT(obh != NULL);
575 blocknr = read_tag_block(tag_bytes,
576 tag);
577
578 /* If the block has been
579 * revoked, then we're all done
580 * here. */
581 if (jbd2_journal_test_revoke
582 (journal, blocknr,
583 next_commit_ID)) {
584 brelse(obh);
585 ++info->nr_revoke_hits;
586 goto skip_write;
587 }
588
589 /* Look for block corruption */
590 if (!jbd2_block_tag_csum_verify(
591 journal, tag, obh->b_data,
592 be32_to_cpu(tmp->h_sequence))) {
593 brelse(obh);
594 success = -EIO;
595 printk(KERN_ERR "JBD: Invalid "
596 "checksum recovering "
597 "block %llu in log\n",
598 blocknr);
599 continue;
600 }
601
602 /* Find a buffer for the new
603 * data being restored */
604 nbh = __getblk(journal->j_fs_dev,
605 blocknr,
606 journal->j_blocksize);
607 if (nbh == NULL) {
608 printk(KERN_ERR
609 "JBD2: Out of memory "
610 "during recovery.\n");
611 err = -ENOMEM;
612 brelse(bh);
613 brelse(obh);
614 goto failed;
615 }
616
617 lock_buffer(nbh);
618 memcpy(nbh->b_data, obh->b_data,
619 journal->j_blocksize);
620 if (flags & JBD2_FLAG_ESCAPE) {
621 *((__be32 *)nbh->b_data) =
622 cpu_to_be32(JBD2_MAGIC_NUMBER);
623 }
624
625 BUFFER_TRACE(nbh, "marking dirty");
626 set_buffer_uptodate(nbh);
627 mark_buffer_dirty(nbh);
628 BUFFER_TRACE(nbh, "marking uptodate");
629 ++info->nr_replays;
630 /* ll_rw_block(WRITE, 1, &nbh); */
631 unlock_buffer(nbh);
632 brelse(obh);
633 brelse(nbh);
634 }
635
636 skip_write:
637 tagp += tag_bytes;
638 if (!(flags & JBD2_FLAG_SAME_UUID))
639 tagp += 16;
640
641 if (flags & JBD2_FLAG_LAST_TAG)
642 break;
643 }
644
645 brelse(bh);
646 continue;
647
648 case JBD2_COMMIT_BLOCK:
649 /* How to differentiate between interrupted commit
650 * and journal corruption ?
651 *
652 * {nth transaction}
653 * Checksum Verification Failed
654 * |
655 * ____________________
656 * | |
657 * async_commit sync_commit
658 * | |
659 * | GO TO NEXT "Journal Corruption"
660 * | TRANSACTION
661 * |
662 * {(n+1)th transanction}
663 * |
664 * _______|______________
665 * | |
666 * Commit block found Commit block not found
667 * | |
668 * "Journal Corruption" |
669 * _____________|_________
670 * | |
671 * nth trans corrupt OR nth trans
672 * and (n+1)th interrupted interrupted
673 * before commit block
674 * could reach the disk.
675 * (Cannot find the difference in above
676 * mentioned conditions. Hence assume
677 * "Interrupted Commit".)
678 */
679
680 /* Found an expected commit block: if checksums
681 * are present verify them in PASS_SCAN; else not
682 * much to do other than move on to the next sequence
683 * number. */
684 if (pass == PASS_SCAN &&
685 JBD2_HAS_COMPAT_FEATURE(journal,
686 JBD2_FEATURE_COMPAT_CHECKSUM)) {
687 int chksum_err, chksum_seen;
688 struct commit_header *cbh =
689 (struct commit_header *)bh->b_data;
690 unsigned found_chksum =
691 be32_to_cpu(cbh->h_chksum[0]);
692
693 chksum_err = chksum_seen = 0;
694
695 if (info->end_transaction) {
696 journal->j_failed_commit =
697 info->end_transaction;
698 brelse(bh);
699 break;
700 }
701
702 if (crc32_sum == found_chksum &&
703 cbh->h_chksum_type == JBD2_CRC32_CHKSUM &&
704 cbh->h_chksum_size ==
705 JBD2_CRC32_CHKSUM_SIZE)
706 chksum_seen = 1;
707 else if (!(cbh->h_chksum_type == 0 &&
708 cbh->h_chksum_size == 0 &&
709 found_chksum == 0 &&
710 !chksum_seen))
711 /*
712 * If fs is mounted using an old kernel and then
713 * kernel with journal_chksum is used then we
714 * get a situation where the journal flag has
715 * checksum flag set but checksums are not
716 * present i.e chksum = 0, in the individual
717 * commit blocks.
718 * Hence to avoid checksum failures, in this
719 * situation, this extra check is added.
720 */
721 chksum_err = 1;
722
723 if (chksum_err) {
724 info->end_transaction = next_commit_ID;
725
726 if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
727 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)){
728 journal->j_failed_commit =
729 next_commit_ID;
730 brelse(bh);
731 break;
732 }
733 }
734 crc32_sum = ~0;
735 }
736 if (pass == PASS_SCAN &&
737 !jbd2_commit_block_csum_verify(journal,
738 bh->b_data)) {
739 info->end_transaction = next_commit_ID;
740
741 if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
742 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
743 journal->j_failed_commit =
744 next_commit_ID;
745 brelse(bh);
746 break;
747 }
748 }
749 brelse(bh);
750 next_commit_ID++;
751 continue;
752
753 case JBD2_REVOKE_BLOCK:
754 /* If we aren't in the REVOKE pass, then we can
755 * just skip over this block. */
756 if (pass != PASS_REVOKE) {
757 brelse(bh);
758 continue;
759 }
760
761 err = scan_revoke_records(journal, bh,
762 next_commit_ID, info);
763 brelse(bh);
764 if (err)
765 goto failed;
766 continue;
767
768 default:
769 jbd_debug(3, "Unrecognised magic %d, end of scan.\n",
770 blocktype);
771 brelse(bh);
772 goto done;
773 }
774 }
775
776 done:
777 /*
778 * We broke out of the log scan loop: either we came to the
779 * known end of the log or we found an unexpected block in the
780 * log. If the latter happened, then we know that the "current"
781 * transaction marks the end of the valid log.
782 */
783
784 if (pass == PASS_SCAN) {
785 if (!info->end_transaction)
786 info->end_transaction = next_commit_ID;
787 } else {
788 /* It's really bad news if different passes end up at
789 * different places (but possible due to IO errors). */
790 if (info->end_transaction != next_commit_ID) {
791 printk(KERN_ERR "JBD2: recovery pass %d ended at "
792 "transaction %u, expected %u\n",
793 pass, next_commit_ID, info->end_transaction);
794 if (!success)
795 success = -EIO;
796 }
797 }
798
799 return success;
800
801 failed:
802 return err;
803}
804
805static int jbd2_revoke_block_csum_verify(journal_t *j,
806 void *buf)
807{
808 struct jbd2_journal_revoke_tail *tail;
809 __u32 provided, calculated;
810
811 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
812 return 1;
813
814 tail = (struct jbd2_journal_revoke_tail *)(buf + j->j_blocksize -
815 sizeof(struct jbd2_journal_revoke_tail));
816 provided = tail->r_checksum;
817 tail->r_checksum = 0;
818 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
819 tail->r_checksum = provided;
820
821 provided = be32_to_cpu(provided);
822 return provided == calculated;
823}
824
825/* Scan a revoke record, marking all blocks mentioned as revoked. */
826
827static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
828 tid_t sequence, struct recovery_info *info)
829{
830 jbd2_journal_revoke_header_t *header;
831 int offset, max;
832 int record_len = 4;
833
834 header = (jbd2_journal_revoke_header_t *) bh->b_data;
835 offset = sizeof(jbd2_journal_revoke_header_t);
836 max = be32_to_cpu(header->r_count);
837
838 if (!jbd2_revoke_block_csum_verify(journal, header))
839 return -EINVAL;
840
841 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
842 record_len = 8;
843
844 while (offset + record_len <= max) {
845 unsigned long long blocknr;
846 int err;
847
848 if (record_len == 4)
849 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
850 else
851 blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset)));
852 offset += record_len;
853 err = jbd2_journal_set_revoke(journal, blocknr, sequence);
854 if (err)
855 return err;
856 ++info->nr_revokes;
857 }
858 return 0;
859}