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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#endif
25
26/*
27 * Maintain information about the progress of the recovery job, so that
28 * the different passes can carry information between them.
29 */
30struct recovery_info
31{
32 tid_t start_transaction;
33 tid_t end_transaction;
34
35 int nr_replays;
36 int nr_revokes;
37 int nr_revoke_hits;
38};
39
40enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY};
41static int do_one_pass(journal_t *journal,
42 struct recovery_info *info, enum passtype pass);
43static int scan_revoke_records(journal_t *, struct buffer_head *,
44 tid_t, struct recovery_info *);
45
46#ifdef __KERNEL__
47
48/* Release readahead buffers after use */
49static void journal_brelse_array(struct buffer_head *b[], int n)
50{
51 while (--n >= 0)
52 brelse (b[n]);
53}
54
55
56/*
57 * When reading from the journal, we are going through the block device
58 * layer directly and so there is no readahead being done for us. We
59 * need to implement any readahead ourselves if we want it to happen at
60 * all. Recovery is basically one long sequential read, so make sure we
61 * do the IO in reasonably large chunks.
62 *
63 * This is not so critical that we need to be enormously clever about
64 * the readahead size, though. 128K is a purely arbitrary, good-enough
65 * fixed value.
66 */
67
68#define MAXBUF 8
69static int do_readahead(journal_t *journal, unsigned int start)
70{
71 int err;
72 unsigned int max, nbufs, next;
73 unsigned long long blocknr;
74 struct buffer_head *bh;
75
76 struct buffer_head * bufs[MAXBUF];
77
78 /* Do up to 128K of readahead */
79 max = start + (128 * 1024 / journal->j_blocksize);
80 if (max > journal->j_maxlen)
81 max = journal->j_maxlen;
82
83 /* Do the readahead itself. We'll submit MAXBUF buffer_heads at
84 * a time to the block device IO layer. */
85
86 nbufs = 0;
87
88 for (next = start; next < max; next++) {
89 err = jbd2_journal_bmap(journal, next, &blocknr);
90
91 if (err) {
92 printk (KERN_ERR "JBD: bad block at offset %u\n",
93 next);
94 goto failed;
95 }
96
97 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
98 if (!bh) {
99 err = -ENOMEM;
100 goto failed;
101 }
102
103 if (!buffer_uptodate(bh) && !buffer_locked(bh)) {
104 bufs[nbufs++] = bh;
105 if (nbufs == MAXBUF) {
106 ll_rw_block(READ, nbufs, bufs);
107 journal_brelse_array(bufs, nbufs);
108 nbufs = 0;
109 }
110 } else
111 brelse(bh);
112 }
113
114 if (nbufs)
115 ll_rw_block(READ, nbufs, bufs);
116 err = 0;
117
118failed:
119 if (nbufs)
120 journal_brelse_array(bufs, nbufs);
121 return err;
122}
123
124#endif /* __KERNEL__ */
125
126
127/*
128 * Read a block from the journal
129 */
130
131static int jread(struct buffer_head **bhp, journal_t *journal,
132 unsigned int offset)
133{
134 int err;
135 unsigned long long blocknr;
136 struct buffer_head *bh;
137
138 *bhp = NULL;
139
140 if (offset >= journal->j_maxlen) {
141 printk(KERN_ERR "JBD: corrupted journal superblock\n");
142 return -EIO;
143 }
144
145 err = jbd2_journal_bmap(journal, offset, &blocknr);
146
147 if (err) {
148 printk (KERN_ERR "JBD: bad block at offset %u\n",
149 offset);
150 return err;
151 }
152
153 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
154 if (!bh)
155 return -ENOMEM;
156
157 if (!buffer_uptodate(bh)) {
158 /* If this is a brand new buffer, start readahead.
159 Otherwise, we assume we are already reading it. */
160 if (!buffer_req(bh))
161 do_readahead(journal, offset);
162 wait_on_buffer(bh);
163 }
164
165 if (!buffer_uptodate(bh)) {
166 printk (KERN_ERR "JBD: Failed to read block at offset %u\n",
167 offset);
168 brelse(bh);
169 return -EIO;
170 }
171
172 *bhp = bh;
173 return 0;
174}
175
176
177/*
178 * Count the number of in-use tags in a journal descriptor block.
179 */
180
181static int count_tags(journal_t *journal, struct buffer_head *bh)
182{
183 char * tagp;
184 journal_block_tag_t * tag;
185 int nr = 0, size = journal->j_blocksize;
186 int tag_bytes = journal_tag_bytes(journal);
187
188 tagp = &bh->b_data[sizeof(journal_header_t)];
189
190 while ((tagp - bh->b_data + tag_bytes) <= size) {
191 tag = (journal_block_tag_t *) tagp;
192
193 nr++;
194 tagp += tag_bytes;
195 if (!(tag->t_flags & cpu_to_be32(JBD2_FLAG_SAME_UUID)))
196 tagp += 16;
197
198 if (tag->t_flags & cpu_to_be32(JBD2_FLAG_LAST_TAG))
199 break;
200 }
201
202 return nr;
203}
204
205
206/* Make sure we wrap around the log correctly! */
207#define wrap(journal, var) \
208do { \
209 if (var >= (journal)->j_last) \
210 var -= ((journal)->j_last - (journal)->j_first); \
211} while (0)
212
213/**
214 * jbd2_journal_recover - recovers a on-disk journal
215 * @journal: the journal to recover
216 *
217 * The primary function for recovering the log contents when mounting a
218 * journaled device.
219 *
220 * Recovery is done in three passes. In the first pass, we look for the
221 * end of the log. In the second, we assemble the list of revoke
222 * blocks. In the third and final pass, we replay any un-revoked blocks
223 * in the log.
224 */
225int jbd2_journal_recover(journal_t *journal)
226{
227 int err, err2;
228 journal_superblock_t * sb;
229
230 struct recovery_info info;
231
232 memset(&info, 0, sizeof(info));
233 sb = journal->j_superblock;
234
235 /*
236 * The journal superblock's s_start field (the current log head)
237 * is always zero if, and only if, the journal was cleanly
238 * unmounted.
239 */
240
241 if (!sb->s_start) {
242 jbd_debug(1, "No recovery required, last transaction %d\n",
243 be32_to_cpu(sb->s_sequence));
244 journal->j_transaction_sequence = be32_to_cpu(sb->s_sequence) + 1;
245 return 0;
246 }
247
248 err = do_one_pass(journal, &info, PASS_SCAN);
249 if (!err)
250 err = do_one_pass(journal, &info, PASS_REVOKE);
251 if (!err)
252 err = do_one_pass(journal, &info, PASS_REPLAY);
253
254 jbd_debug(1, "JBD: recovery, exit status %d, "
255 "recovered transactions %u to %u\n",
256 err, info.start_transaction, info.end_transaction);
257 jbd_debug(1, "JBD: Replayed %d and revoked %d/%d blocks\n",
258 info.nr_replays, info.nr_revoke_hits, info.nr_revokes);
259
260 /* Restart the log at the next transaction ID, thus invalidating
261 * any existing commit records in the log. */
262 journal->j_transaction_sequence = ++info.end_transaction;
263
264 jbd2_journal_clear_revoke(journal);
265 err2 = sync_blockdev(journal->j_fs_dev);
266 if (!err)
267 err = err2;
268
269 return err;
270}
271
272/**
273 * jbd2_journal_skip_recovery - Start journal and wipe exiting records
274 * @journal: journal to startup
275 *
276 * Locate any valid recovery information from the journal and set up the
277 * journal structures in memory to ignore it (presumably because the
278 * caller has evidence that it is out of date).
279 * This function does'nt appear to be exorted..
280 *
281 * We perform one pass over the journal to allow us to tell the user how
282 * much recovery information is being erased, and to let us initialise
283 * the journal transaction sequence numbers to the next unused ID.
284 */
285int jbd2_journal_skip_recovery(journal_t *journal)
286{
287 int err;
288
289 struct recovery_info info;
290
291 memset (&info, 0, sizeof(info));
292
293 err = do_one_pass(journal, &info, PASS_SCAN);
294
295 if (err) {
296 printk(KERN_ERR "JBD: error %d scanning journal\n", err);
297 ++journal->j_transaction_sequence;
298 } else {
299#ifdef CONFIG_JBD2_DEBUG
300 int dropped = info.end_transaction -
301 be32_to_cpu(journal->j_superblock->s_sequence);
302 jbd_debug(1,
303 "JBD: ignoring %d transaction%s from the journal.\n",
304 dropped, (dropped == 1) ? "" : "s");
305#endif
306 journal->j_transaction_sequence = ++info.end_transaction;
307 }
308
309 journal->j_tail = 0;
310 return err;
311}
312
313static inline unsigned long long read_tag_block(int tag_bytes, journal_block_tag_t *tag)
314{
315 unsigned long long block = be32_to_cpu(tag->t_blocknr);
316 if (tag_bytes > JBD2_TAG_SIZE32)
317 block |= (u64)be32_to_cpu(tag->t_blocknr_high) << 32;
318 return block;
319}
320
321/*
322 * calc_chksums calculates the checksums for the blocks described in the
323 * descriptor block.
324 */
325static int calc_chksums(journal_t *journal, struct buffer_head *bh,
326 unsigned long *next_log_block, __u32 *crc32_sum)
327{
328 int i, num_blks, err;
329 unsigned long io_block;
330 struct buffer_head *obh;
331
332 num_blks = count_tags(journal, bh);
333 /* Calculate checksum of the descriptor block. */
334 *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size);
335
336 for (i = 0; i < num_blks; i++) {
337 io_block = (*next_log_block)++;
338 wrap(journal, *next_log_block);
339 err = jread(&obh, journal, io_block);
340 if (err) {
341 printk(KERN_ERR "JBD: IO error %d recovering block "
342 "%lu in log\n", err, io_block);
343 return 1;
344 } else {
345 *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data,
346 obh->b_size);
347 }
348 put_bh(obh);
349 }
350 return 0;
351}
352
353static int do_one_pass(journal_t *journal,
354 struct recovery_info *info, enum passtype pass)
355{
356 unsigned int first_commit_ID, next_commit_ID;
357 unsigned long next_log_block;
358 int err, success = 0;
359 journal_superblock_t * sb;
360 journal_header_t * tmp;
361 struct buffer_head * bh;
362 unsigned int sequence;
363 int blocktype;
364 int tag_bytes = journal_tag_bytes(journal);
365 __u32 crc32_sum = ~0; /* Transactional Checksums */
366
367 /*
368 * First thing is to establish what we expect to find in the log
369 * (in terms of transaction IDs), and where (in terms of log
370 * block offsets): query the superblock.
371 */
372
373 sb = journal->j_superblock;
374 next_commit_ID = be32_to_cpu(sb->s_sequence);
375 next_log_block = be32_to_cpu(sb->s_start);
376
377 first_commit_ID = next_commit_ID;
378 if (pass == PASS_SCAN)
379 info->start_transaction = first_commit_ID;
380
381 jbd_debug(1, "Starting recovery pass %d\n", pass);
382
383 /*
384 * Now we walk through the log, transaction by transaction,
385 * making sure that each transaction has a commit block in the
386 * expected place. Each complete transaction gets replayed back
387 * into the main filesystem.
388 */
389
390 while (1) {
391 int flags;
392 char * tagp;
393 journal_block_tag_t * tag;
394 struct buffer_head * obh;
395 struct buffer_head * nbh;
396
397 cond_resched();
398
399 /* If we already know where to stop the log traversal,
400 * check right now that we haven't gone past the end of
401 * the log. */
402
403 if (pass != PASS_SCAN)
404 if (tid_geq(next_commit_ID, info->end_transaction))
405 break;
406
407 jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
408 next_commit_ID, next_log_block, journal->j_last);
409
410 /* Skip over each chunk of the transaction looking
411 * either the next descriptor block or the final commit
412 * record. */
413
414 jbd_debug(3, "JBD: checking block %ld\n", next_log_block);
415 err = jread(&bh, journal, next_log_block);
416 if (err)
417 goto failed;
418
419 next_log_block++;
420 wrap(journal, next_log_block);
421
422 /* What kind of buffer is it?
423 *
424 * If it is a descriptor block, check that it has the
425 * expected sequence number. Otherwise, we're all done
426 * here. */
427
428 tmp = (journal_header_t *)bh->b_data;
429
430 if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) {
431 brelse(bh);
432 break;
433 }
434
435 blocktype = be32_to_cpu(tmp->h_blocktype);
436 sequence = be32_to_cpu(tmp->h_sequence);
437 jbd_debug(3, "Found magic %d, sequence %d\n",
438 blocktype, sequence);
439
440 if (sequence != next_commit_ID) {
441 brelse(bh);
442 break;
443 }
444
445 /* OK, we have a valid descriptor block which matches
446 * all of the sequence number checks. What are we going
447 * to do with it? That depends on the pass... */
448
449 switch(blocktype) {
450 case JBD2_DESCRIPTOR_BLOCK:
451 /* If it is a valid descriptor block, replay it
452 * in pass REPLAY; if journal_checksums enabled, then
453 * calculate checksums in PASS_SCAN, otherwise,
454 * just skip over the blocks it describes. */
455 if (pass != PASS_REPLAY) {
456 if (pass == PASS_SCAN &&
457 JBD2_HAS_COMPAT_FEATURE(journal,
458 JBD2_FEATURE_COMPAT_CHECKSUM) &&
459 !info->end_transaction) {
460 if (calc_chksums(journal, bh,
461 &next_log_block,
462 &crc32_sum)) {
463 put_bh(bh);
464 break;
465 }
466 put_bh(bh);
467 continue;
468 }
469 next_log_block += count_tags(journal, bh);
470 wrap(journal, next_log_block);
471 put_bh(bh);
472 continue;
473 }
474
475 /* A descriptor block: we can now write all of
476 * the data blocks. Yay, useful work is finally
477 * getting done here! */
478
479 tagp = &bh->b_data[sizeof(journal_header_t)];
480 while ((tagp - bh->b_data + tag_bytes)
481 <= journal->j_blocksize) {
482 unsigned long io_block;
483
484 tag = (journal_block_tag_t *) tagp;
485 flags = be32_to_cpu(tag->t_flags);
486
487 io_block = next_log_block++;
488 wrap(journal, next_log_block);
489 err = jread(&obh, journal, io_block);
490 if (err) {
491 /* Recover what we can, but
492 * report failure at the end. */
493 success = err;
494 printk (KERN_ERR
495 "JBD: IO error %d recovering "
496 "block %ld in log\n",
497 err, io_block);
498 } else {
499 unsigned long long blocknr;
500
501 J_ASSERT(obh != NULL);
502 blocknr = read_tag_block(tag_bytes,
503 tag);
504
505 /* If the block has been
506 * revoked, then we're all done
507 * here. */
508 if (jbd2_journal_test_revoke
509 (journal, blocknr,
510 next_commit_ID)) {
511 brelse(obh);
512 ++info->nr_revoke_hits;
513 goto skip_write;
514 }
515
516 /* Find a buffer for the new
517 * data being restored */
518 nbh = __getblk(journal->j_fs_dev,
519 blocknr,
520 journal->j_blocksize);
521 if (nbh == NULL) {
522 printk(KERN_ERR
523 "JBD: Out of memory "
524 "during recovery.\n");
525 err = -ENOMEM;
526 brelse(bh);
527 brelse(obh);
528 goto failed;
529 }
530
531 lock_buffer(nbh);
532 memcpy(nbh->b_data, obh->b_data,
533 journal->j_blocksize);
534 if (flags & JBD2_FLAG_ESCAPE) {
535 *((__be32 *)nbh->b_data) =
536 cpu_to_be32(JBD2_MAGIC_NUMBER);
537 }
538
539 BUFFER_TRACE(nbh, "marking dirty");
540 set_buffer_uptodate(nbh);
541 mark_buffer_dirty(nbh);
542 BUFFER_TRACE(nbh, "marking uptodate");
543 ++info->nr_replays;
544 /* ll_rw_block(WRITE, 1, &nbh); */
545 unlock_buffer(nbh);
546 brelse(obh);
547 brelse(nbh);
548 }
549
550 skip_write:
551 tagp += tag_bytes;
552 if (!(flags & JBD2_FLAG_SAME_UUID))
553 tagp += 16;
554
555 if (flags & JBD2_FLAG_LAST_TAG)
556 break;
557 }
558
559 brelse(bh);
560 continue;
561
562 case JBD2_COMMIT_BLOCK:
563 /* How to differentiate between interrupted commit
564 * and journal corruption ?
565 *
566 * {nth transaction}
567 * Checksum Verification Failed
568 * |
569 * ____________________
570 * | |
571 * async_commit sync_commit
572 * | |
573 * | GO TO NEXT "Journal Corruption"
574 * | TRANSACTION
575 * |
576 * {(n+1)th transanction}
577 * |
578 * _______|______________
579 * | |
580 * Commit block found Commit block not found
581 * | |
582 * "Journal Corruption" |
583 * _____________|_________
584 * | |
585 * nth trans corrupt OR nth trans
586 * and (n+1)th interrupted interrupted
587 * before commit block
588 * could reach the disk.
589 * (Cannot find the difference in above
590 * mentioned conditions. Hence assume
591 * "Interrupted Commit".)
592 */
593
594 /* Found an expected commit block: if checksums
595 * are present verify them in PASS_SCAN; else not
596 * much to do other than move on to the next sequence
597 * number. */
598 if (pass == PASS_SCAN &&
599 JBD2_HAS_COMPAT_FEATURE(journal,
600 JBD2_FEATURE_COMPAT_CHECKSUM)) {
601 int chksum_err, chksum_seen;
602 struct commit_header *cbh =
603 (struct commit_header *)bh->b_data;
604 unsigned found_chksum =
605 be32_to_cpu(cbh->h_chksum[0]);
606
607 chksum_err = chksum_seen = 0;
608
609 if (info->end_transaction) {
610 journal->j_failed_commit =
611 info->end_transaction;
612 brelse(bh);
613 break;
614 }
615
616 if (crc32_sum == found_chksum &&
617 cbh->h_chksum_type == JBD2_CRC32_CHKSUM &&
618 cbh->h_chksum_size ==
619 JBD2_CRC32_CHKSUM_SIZE)
620 chksum_seen = 1;
621 else if (!(cbh->h_chksum_type == 0 &&
622 cbh->h_chksum_size == 0 &&
623 found_chksum == 0 &&
624 !chksum_seen))
625 /*
626 * If fs is mounted using an old kernel and then
627 * kernel with journal_chksum is used then we
628 * get a situation where the journal flag has
629 * checksum flag set but checksums are not
630 * present i.e chksum = 0, in the individual
631 * commit blocks.
632 * Hence to avoid checksum failures, in this
633 * situation, this extra check is added.
634 */
635 chksum_err = 1;
636
637 if (chksum_err) {
638 info->end_transaction = next_commit_ID;
639
640 if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
641 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)){
642 journal->j_failed_commit =
643 next_commit_ID;
644 brelse(bh);
645 break;
646 }
647 }
648 crc32_sum = ~0;
649 }
650 brelse(bh);
651 next_commit_ID++;
652 continue;
653
654 case JBD2_REVOKE_BLOCK:
655 /* If we aren't in the REVOKE pass, then we can
656 * just skip over this block. */
657 if (pass != PASS_REVOKE) {
658 brelse(bh);
659 continue;
660 }
661
662 err = scan_revoke_records(journal, bh,
663 next_commit_ID, info);
664 brelse(bh);
665 if (err)
666 goto failed;
667 continue;
668
669 default:
670 jbd_debug(3, "Unrecognised magic %d, end of scan.\n",
671 blocktype);
672 brelse(bh);
673 goto done;
674 }
675 }
676
677 done:
678 /*
679 * We broke out of the log scan loop: either we came to the
680 * known end of the log or we found an unexpected block in the
681 * log. If the latter happened, then we know that the "current"
682 * transaction marks the end of the valid log.
683 */
684
685 if (pass == PASS_SCAN) {
686 if (!info->end_transaction)
687 info->end_transaction = next_commit_ID;
688 } else {
689 /* It's really bad news if different passes end up at
690 * different places (but possible due to IO errors). */
691 if (info->end_transaction != next_commit_ID) {
692 printk (KERN_ERR "JBD: recovery pass %d ended at "
693 "transaction %u, expected %u\n",
694 pass, next_commit_ID, info->end_transaction);
695 if (!success)
696 success = -EIO;
697 }
698 }
699
700 return success;
701
702 failed:
703 return err;
704}
705
706
707/* Scan a revoke record, marking all blocks mentioned as revoked. */
708
709static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
710 tid_t sequence, struct recovery_info *info)
711{
712 jbd2_journal_revoke_header_t *header;
713 int offset, max;
714 int record_len = 4;
715
716 header = (jbd2_journal_revoke_header_t *) bh->b_data;
717 offset = sizeof(jbd2_journal_revoke_header_t);
718 max = be32_to_cpu(header->r_count);
719
720 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
721 record_len = 8;
722
723 while (offset + record_len <= max) {
724 unsigned long long blocknr;
725 int err;
726
727 if (record_len == 4)
728 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
729 else
730 blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset)));
731 offset += record_len;
732 err = jbd2_journal_set_revoke(journal, blocknr, sequence);
733 if (err)
734 return err;
735 ++info->nr_revokes;
736 }
737 return 0;
738}
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 unsigned long head_block;
33
34 int nr_replays;
35 int nr_revokes;
36 int nr_revoke_hits;
37};
38
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_total_len)
79 max = journal->j_total_len;
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 bh_readahead_batch(nbufs, bufs, 0);
105 journal_brelse_array(bufs, nbufs);
106 nbufs = 0;
107 }
108 } else
109 brelse(bh);
110 }
111
112 if (nbufs)
113 bh_readahead_batch(nbufs, bufs, 0);
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_total_len) {
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 /*
157 * If this is a brand new buffer, start readahead.
158 * Otherwise, we assume we are already reading it.
159 */
160 bool need_readahead = !buffer_req(bh);
161
162 bh_read_nowait(bh, 0);
163 if (need_readahead)
164 do_readahead(journal, offset);
165 wait_on_buffer(bh);
166 }
167
168 if (!buffer_uptodate(bh)) {
169 printk(KERN_ERR "JBD2: Failed to read block at offset %u\n",
170 offset);
171 brelse(bh);
172 return -EIO;
173 }
174
175 *bhp = bh;
176 return 0;
177}
178
179static int jbd2_descriptor_block_csum_verify(journal_t *j, void *buf)
180{
181 struct jbd2_journal_block_tail *tail;
182 __be32 provided;
183 __u32 calculated;
184
185 if (!jbd2_journal_has_csum_v2or3(j))
186 return 1;
187
188 tail = (struct jbd2_journal_block_tail *)((char *)buf +
189 j->j_blocksize - sizeof(struct jbd2_journal_block_tail));
190 provided = tail->t_checksum;
191 tail->t_checksum = 0;
192 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
193 tail->t_checksum = provided;
194
195 return provided == cpu_to_be32(calculated);
196}
197
198/*
199 * Count the number of in-use tags in a journal descriptor block.
200 */
201
202static int count_tags(journal_t *journal, struct buffer_head *bh)
203{
204 char * tagp;
205 journal_block_tag_t tag;
206 int nr = 0, size = journal->j_blocksize;
207 int tag_bytes = journal_tag_bytes(journal);
208
209 if (jbd2_journal_has_csum_v2or3(journal))
210 size -= sizeof(struct jbd2_journal_block_tail);
211
212 tagp = &bh->b_data[sizeof(journal_header_t)];
213
214 while ((tagp - bh->b_data + tag_bytes) <= size) {
215 memcpy(&tag, tagp, sizeof(tag));
216
217 nr++;
218 tagp += tag_bytes;
219 if (!(tag.t_flags & cpu_to_be16(JBD2_FLAG_SAME_UUID)))
220 tagp += 16;
221
222 if (tag.t_flags & cpu_to_be16(JBD2_FLAG_LAST_TAG))
223 break;
224 }
225
226 return nr;
227}
228
229
230/* Make sure we wrap around the log correctly! */
231#define wrap(journal, var) \
232do { \
233 if (var >= (journal)->j_last) \
234 var -= ((journal)->j_last - (journal)->j_first); \
235} while (0)
236
237static int fc_do_one_pass(journal_t *journal,
238 struct recovery_info *info, enum passtype pass)
239{
240 unsigned int expected_commit_id = info->end_transaction;
241 unsigned long next_fc_block;
242 struct buffer_head *bh;
243 int err = 0;
244
245 next_fc_block = journal->j_fc_first;
246 if (!journal->j_fc_replay_callback)
247 return 0;
248
249 while (next_fc_block <= journal->j_fc_last) {
250 jbd2_debug(3, "Fast commit replay: next block %ld\n",
251 next_fc_block);
252 err = jread(&bh, journal, next_fc_block);
253 if (err) {
254 jbd2_debug(3, "Fast commit replay: read error\n");
255 break;
256 }
257
258 err = journal->j_fc_replay_callback(journal, bh, pass,
259 next_fc_block - journal->j_fc_first,
260 expected_commit_id);
261 brelse(bh);
262 next_fc_block++;
263 if (err < 0 || err == JBD2_FC_REPLAY_STOP)
264 break;
265 err = 0;
266 }
267
268 if (err)
269 jbd2_debug(3, "Fast commit replay failed, err = %d\n", err);
270
271 return err;
272}
273
274/**
275 * jbd2_journal_recover - recovers a on-disk journal
276 * @journal: the journal to recover
277 *
278 * The primary function for recovering the log contents when mounting a
279 * journaled device.
280 *
281 * Recovery is done in three passes. In the first pass, we look for the
282 * end of the log. In the second, we assemble the list of revoke
283 * blocks. In the third and final pass, we replay any un-revoked blocks
284 * in the log.
285 */
286int jbd2_journal_recover(journal_t *journal)
287{
288 int err, err2;
289 journal_superblock_t * sb;
290
291 struct recovery_info info;
292
293 memset(&info, 0, sizeof(info));
294 sb = journal->j_superblock;
295
296 /*
297 * The journal superblock's s_start field (the current log head)
298 * is always zero if, and only if, the journal was cleanly
299 * unmounted.
300 */
301 if (!sb->s_start) {
302 jbd2_debug(1, "No recovery required, last transaction %d, head block %u\n",
303 be32_to_cpu(sb->s_sequence), be32_to_cpu(sb->s_head));
304 journal->j_transaction_sequence = be32_to_cpu(sb->s_sequence) + 1;
305 journal->j_head = be32_to_cpu(sb->s_head);
306 return 0;
307 }
308
309 err = do_one_pass(journal, &info, PASS_SCAN);
310 if (!err)
311 err = do_one_pass(journal, &info, PASS_REVOKE);
312 if (!err)
313 err = do_one_pass(journal, &info, PASS_REPLAY);
314
315 jbd2_debug(1, "JBD2: recovery, exit status %d, "
316 "recovered transactions %u to %u\n",
317 err, info.start_transaction, info.end_transaction);
318 jbd2_debug(1, "JBD2: Replayed %d and revoked %d/%d blocks\n",
319 info.nr_replays, info.nr_revoke_hits, info.nr_revokes);
320
321 /* Restart the log at the next transaction ID, thus invalidating
322 * any existing commit records in the log. */
323 journal->j_transaction_sequence = ++info.end_transaction;
324 journal->j_head = info.head_block;
325 jbd2_debug(1, "JBD2: last transaction %d, head block %lu\n",
326 journal->j_transaction_sequence, journal->j_head);
327
328 jbd2_journal_clear_revoke(journal);
329 err2 = sync_blockdev(journal->j_fs_dev);
330 if (!err)
331 err = err2;
332 err2 = jbd2_check_fs_dev_write_error(journal);
333 if (!err)
334 err = err2;
335 /* Make sure all replayed data is on permanent storage */
336 if (journal->j_flags & JBD2_BARRIER) {
337 err2 = blkdev_issue_flush(journal->j_fs_dev);
338 if (!err)
339 err = err2;
340 }
341 return err;
342}
343
344/**
345 * jbd2_journal_skip_recovery - Start journal and wipe exiting records
346 * @journal: journal to startup
347 *
348 * Locate any valid recovery information from the journal and set up the
349 * journal structures in memory to ignore it (presumably because the
350 * caller has evidence that it is out of date).
351 * This function doesn't appear to be exported..
352 *
353 * We perform one pass over the journal to allow us to tell the user how
354 * much recovery information is being erased, and to let us initialise
355 * the journal transaction sequence numbers to the next unused ID.
356 */
357int jbd2_journal_skip_recovery(journal_t *journal)
358{
359 int err;
360
361 struct recovery_info info;
362
363 memset (&info, 0, sizeof(info));
364
365 err = do_one_pass(journal, &info, PASS_SCAN);
366
367 if (err) {
368 printk(KERN_ERR "JBD2: error %d scanning journal\n", err);
369 ++journal->j_transaction_sequence;
370 journal->j_head = journal->j_first;
371 } else {
372#ifdef CONFIG_JBD2_DEBUG
373 int dropped = info.end_transaction -
374 be32_to_cpu(journal->j_superblock->s_sequence);
375 jbd2_debug(1,
376 "JBD2: ignoring %d transaction%s from the journal.\n",
377 dropped, (dropped == 1) ? "" : "s");
378#endif
379 journal->j_transaction_sequence = ++info.end_transaction;
380 journal->j_head = info.head_block;
381 }
382
383 journal->j_tail = 0;
384 return err;
385}
386
387static inline unsigned long long read_tag_block(journal_t *journal,
388 journal_block_tag_t *tag)
389{
390 unsigned long long block = be32_to_cpu(tag->t_blocknr);
391 if (jbd2_has_feature_64bit(journal))
392 block |= (u64)be32_to_cpu(tag->t_blocknr_high) << 32;
393 return block;
394}
395
396/*
397 * calc_chksums calculates the checksums for the blocks described in the
398 * descriptor block.
399 */
400static int calc_chksums(journal_t *journal, struct buffer_head *bh,
401 unsigned long *next_log_block, __u32 *crc32_sum)
402{
403 int i, num_blks, err;
404 unsigned long io_block;
405 struct buffer_head *obh;
406
407 num_blks = count_tags(journal, bh);
408 /* Calculate checksum of the descriptor block. */
409 *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size);
410
411 for (i = 0; i < num_blks; i++) {
412 io_block = (*next_log_block)++;
413 wrap(journal, *next_log_block);
414 err = jread(&obh, journal, io_block);
415 if (err) {
416 printk(KERN_ERR "JBD2: IO error %d recovering block "
417 "%lu in log\n", err, io_block);
418 return 1;
419 } else {
420 *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data,
421 obh->b_size);
422 }
423 put_bh(obh);
424 }
425 return 0;
426}
427
428static int jbd2_commit_block_csum_verify(journal_t *j, void *buf)
429{
430 struct commit_header *h;
431 __be32 provided;
432 __u32 calculated;
433
434 if (!jbd2_journal_has_csum_v2or3(j))
435 return 1;
436
437 h = buf;
438 provided = h->h_chksum[0];
439 h->h_chksum[0] = 0;
440 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
441 h->h_chksum[0] = provided;
442
443 return provided == cpu_to_be32(calculated);
444}
445
446static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag,
447 journal_block_tag3_t *tag3,
448 void *buf, __u32 sequence)
449{
450 __u32 csum32;
451 __be32 seq;
452
453 if (!jbd2_journal_has_csum_v2or3(j))
454 return 1;
455
456 seq = cpu_to_be32(sequence);
457 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
458 csum32 = jbd2_chksum(j, csum32, buf, j->j_blocksize);
459
460 if (jbd2_has_feature_csum3(j))
461 return tag3->t_checksum == cpu_to_be32(csum32);
462 else
463 return tag->t_checksum == cpu_to_be16(csum32);
464}
465
466static int do_one_pass(journal_t *journal,
467 struct recovery_info *info, enum passtype pass)
468{
469 unsigned int first_commit_ID, next_commit_ID;
470 unsigned long next_log_block, head_block;
471 int err, success = 0;
472 journal_superblock_t * sb;
473 journal_header_t * tmp;
474 struct buffer_head * bh;
475 unsigned int sequence;
476 int blocktype;
477 int tag_bytes = journal_tag_bytes(journal);
478 __u32 crc32_sum = ~0; /* Transactional Checksums */
479 int descr_csum_size = 0;
480 int block_error = 0;
481 bool need_check_commit_time = false;
482 __u64 last_trans_commit_time = 0, commit_time;
483
484 /*
485 * First thing is to establish what we expect to find in the log
486 * (in terms of transaction IDs), and where (in terms of log
487 * block offsets): query the superblock.
488 */
489
490 sb = journal->j_superblock;
491 next_commit_ID = be32_to_cpu(sb->s_sequence);
492 next_log_block = be32_to_cpu(sb->s_start);
493 head_block = next_log_block;
494
495 first_commit_ID = next_commit_ID;
496 if (pass == PASS_SCAN)
497 info->start_transaction = first_commit_ID;
498
499 jbd2_debug(1, "Starting recovery pass %d\n", pass);
500
501 /*
502 * Now we walk through the log, transaction by transaction,
503 * making sure that each transaction has a commit block in the
504 * expected place. Each complete transaction gets replayed back
505 * into the main filesystem.
506 */
507
508 while (1) {
509 int flags;
510 char * tagp;
511 journal_block_tag_t tag;
512 struct buffer_head * obh;
513 struct buffer_head * nbh;
514
515 cond_resched();
516
517 /* If we already know where to stop the log traversal,
518 * check right now that we haven't gone past the end of
519 * the log. */
520
521 if (pass != PASS_SCAN)
522 if (tid_geq(next_commit_ID, info->end_transaction))
523 break;
524
525 jbd2_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
526 next_commit_ID, next_log_block, journal->j_last);
527
528 /* Skip over each chunk of the transaction looking
529 * either the next descriptor block or the final commit
530 * record. */
531
532 jbd2_debug(3, "JBD2: checking block %ld\n", next_log_block);
533 err = jread(&bh, journal, next_log_block);
534 if (err)
535 goto failed;
536
537 next_log_block++;
538 wrap(journal, next_log_block);
539
540 /* What kind of buffer is it?
541 *
542 * If it is a descriptor block, check that it has the
543 * expected sequence number. Otherwise, we're all done
544 * here. */
545
546 tmp = (journal_header_t *)bh->b_data;
547
548 if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) {
549 brelse(bh);
550 break;
551 }
552
553 blocktype = be32_to_cpu(tmp->h_blocktype);
554 sequence = be32_to_cpu(tmp->h_sequence);
555 jbd2_debug(3, "Found magic %d, sequence %d\n",
556 blocktype, sequence);
557
558 if (sequence != next_commit_ID) {
559 brelse(bh);
560 break;
561 }
562
563 /* OK, we have a valid descriptor block which matches
564 * all of the sequence number checks. What are we going
565 * to do with it? That depends on the pass... */
566
567 switch(blocktype) {
568 case JBD2_DESCRIPTOR_BLOCK:
569 /* Verify checksum first */
570 if (jbd2_journal_has_csum_v2or3(journal))
571 descr_csum_size =
572 sizeof(struct jbd2_journal_block_tail);
573 if (descr_csum_size > 0 &&
574 !jbd2_descriptor_block_csum_verify(journal,
575 bh->b_data)) {
576 /*
577 * PASS_SCAN can see stale blocks due to lazy
578 * journal init. Don't error out on those yet.
579 */
580 if (pass != PASS_SCAN) {
581 pr_err("JBD2: Invalid checksum recovering block %lu in log\n",
582 next_log_block);
583 err = -EFSBADCRC;
584 brelse(bh);
585 goto failed;
586 }
587 need_check_commit_time = true;
588 jbd2_debug(1,
589 "invalid descriptor block found in %lu\n",
590 next_log_block);
591 }
592
593 /* If it is a valid descriptor block, replay it
594 * in pass REPLAY; if journal_checksums enabled, then
595 * calculate checksums in PASS_SCAN, otherwise,
596 * just skip over the blocks it describes. */
597 if (pass != PASS_REPLAY) {
598 if (pass == PASS_SCAN &&
599 jbd2_has_feature_checksum(journal) &&
600 !need_check_commit_time &&
601 !info->end_transaction) {
602 if (calc_chksums(journal, bh,
603 &next_log_block,
604 &crc32_sum)) {
605 put_bh(bh);
606 break;
607 }
608 put_bh(bh);
609 continue;
610 }
611 next_log_block += count_tags(journal, bh);
612 wrap(journal, next_log_block);
613 put_bh(bh);
614 continue;
615 }
616
617 /* A descriptor block: we can now write all of
618 * the data blocks. Yay, useful work is finally
619 * getting done here! */
620
621 tagp = &bh->b_data[sizeof(journal_header_t)];
622 while ((tagp - bh->b_data + tag_bytes)
623 <= journal->j_blocksize - descr_csum_size) {
624 unsigned long io_block;
625
626 memcpy(&tag, tagp, sizeof(tag));
627 flags = be16_to_cpu(tag.t_flags);
628
629 io_block = next_log_block++;
630 wrap(journal, next_log_block);
631 err = jread(&obh, journal, io_block);
632 if (err) {
633 /* Recover what we can, but
634 * report failure at the end. */
635 success = err;
636 printk(KERN_ERR
637 "JBD2: IO error %d recovering "
638 "block %lu in log\n",
639 err, io_block);
640 } else {
641 unsigned long long blocknr;
642
643 J_ASSERT(obh != NULL);
644 blocknr = read_tag_block(journal,
645 &tag);
646
647 /* If the block has been
648 * revoked, then we're all done
649 * here. */
650 if (jbd2_journal_test_revoke
651 (journal, blocknr,
652 next_commit_ID)) {
653 brelse(obh);
654 ++info->nr_revoke_hits;
655 goto skip_write;
656 }
657
658 /* Look for block corruption */
659 if (!jbd2_block_tag_csum_verify(
660 journal, &tag, (journal_block_tag3_t *)tagp,
661 obh->b_data, be32_to_cpu(tmp->h_sequence))) {
662 brelse(obh);
663 success = -EFSBADCRC;
664 printk(KERN_ERR "JBD2: Invalid "
665 "checksum recovering "
666 "data block %llu in "
667 "journal block %lu\n",
668 blocknr, io_block);
669 block_error = 1;
670 goto skip_write;
671 }
672
673 /* Find a buffer for the new
674 * data being restored */
675 nbh = __getblk(journal->j_fs_dev,
676 blocknr,
677 journal->j_blocksize);
678 if (nbh == NULL) {
679 printk(KERN_ERR
680 "JBD2: Out of memory "
681 "during recovery.\n");
682 err = -ENOMEM;
683 brelse(bh);
684 brelse(obh);
685 goto failed;
686 }
687
688 lock_buffer(nbh);
689 memcpy(nbh->b_data, obh->b_data,
690 journal->j_blocksize);
691 if (flags & JBD2_FLAG_ESCAPE) {
692 *((__be32 *)nbh->b_data) =
693 cpu_to_be32(JBD2_MAGIC_NUMBER);
694 }
695
696 BUFFER_TRACE(nbh, "marking dirty");
697 set_buffer_uptodate(nbh);
698 mark_buffer_dirty(nbh);
699 BUFFER_TRACE(nbh, "marking uptodate");
700 ++info->nr_replays;
701 unlock_buffer(nbh);
702 brelse(obh);
703 brelse(nbh);
704 }
705
706 skip_write:
707 tagp += tag_bytes;
708 if (!(flags & JBD2_FLAG_SAME_UUID))
709 tagp += 16;
710
711 if (flags & JBD2_FLAG_LAST_TAG)
712 break;
713 }
714
715 brelse(bh);
716 continue;
717
718 case JBD2_COMMIT_BLOCK:
719 /* How to differentiate between interrupted commit
720 * and journal corruption ?
721 *
722 * {nth transaction}
723 * Checksum Verification Failed
724 * |
725 * ____________________
726 * | |
727 * async_commit sync_commit
728 * | |
729 * | GO TO NEXT "Journal Corruption"
730 * | TRANSACTION
731 * |
732 * {(n+1)th transanction}
733 * |
734 * _______|______________
735 * | |
736 * Commit block found Commit block not found
737 * | |
738 * "Journal Corruption" |
739 * _____________|_________
740 * | |
741 * nth trans corrupt OR nth trans
742 * and (n+1)th interrupted interrupted
743 * before commit block
744 * could reach the disk.
745 * (Cannot find the difference in above
746 * mentioned conditions. Hence assume
747 * "Interrupted Commit".)
748 */
749 commit_time = be64_to_cpu(
750 ((struct commit_header *)bh->b_data)->h_commit_sec);
751 /*
752 * If need_check_commit_time is set, it means we are in
753 * PASS_SCAN and csum verify failed before. If
754 * commit_time is increasing, it's the same journal,
755 * otherwise it is stale journal block, just end this
756 * recovery.
757 */
758 if (need_check_commit_time) {
759 if (commit_time >= last_trans_commit_time) {
760 pr_err("JBD2: Invalid checksum found in transaction %u\n",
761 next_commit_ID);
762 err = -EFSBADCRC;
763 brelse(bh);
764 goto failed;
765 }
766 ignore_crc_mismatch:
767 /*
768 * It likely does not belong to same journal,
769 * just end this recovery with success.
770 */
771 jbd2_debug(1, "JBD2: Invalid checksum ignored in transaction %u, likely stale data\n",
772 next_commit_ID);
773 brelse(bh);
774 goto done;
775 }
776
777 /*
778 * Found an expected commit block: if checksums
779 * are present, verify them in PASS_SCAN; else not
780 * much to do other than move on to the next sequence
781 * number.
782 */
783 if (pass == PASS_SCAN &&
784 jbd2_has_feature_checksum(journal)) {
785 struct commit_header *cbh =
786 (struct commit_header *)bh->b_data;
787 unsigned found_chksum =
788 be32_to_cpu(cbh->h_chksum[0]);
789
790 if (info->end_transaction) {
791 journal->j_failed_commit =
792 info->end_transaction;
793 brelse(bh);
794 break;
795 }
796
797 /* Neither checksum match nor unused? */
798 if (!((crc32_sum == found_chksum &&
799 cbh->h_chksum_type ==
800 JBD2_CRC32_CHKSUM &&
801 cbh->h_chksum_size ==
802 JBD2_CRC32_CHKSUM_SIZE) ||
803 (cbh->h_chksum_type == 0 &&
804 cbh->h_chksum_size == 0 &&
805 found_chksum == 0)))
806 goto chksum_error;
807
808 crc32_sum = ~0;
809 }
810 if (pass == PASS_SCAN &&
811 !jbd2_commit_block_csum_verify(journal,
812 bh->b_data)) {
813 chksum_error:
814 if (commit_time < last_trans_commit_time)
815 goto ignore_crc_mismatch;
816 info->end_transaction = next_commit_ID;
817 info->head_block = head_block;
818
819 if (!jbd2_has_feature_async_commit(journal)) {
820 journal->j_failed_commit =
821 next_commit_ID;
822 brelse(bh);
823 break;
824 }
825 }
826 if (pass == PASS_SCAN) {
827 last_trans_commit_time = commit_time;
828 head_block = next_log_block;
829 }
830 brelse(bh);
831 next_commit_ID++;
832 continue;
833
834 case JBD2_REVOKE_BLOCK:
835 /*
836 * Check revoke block crc in pass_scan, if csum verify
837 * failed, check commit block time later.
838 */
839 if (pass == PASS_SCAN &&
840 !jbd2_descriptor_block_csum_verify(journal,
841 bh->b_data)) {
842 jbd2_debug(1, "JBD2: invalid revoke block found in %lu\n",
843 next_log_block);
844 need_check_commit_time = true;
845 }
846 /* If we aren't in the REVOKE pass, then we can
847 * just skip over this block. */
848 if (pass != PASS_REVOKE) {
849 brelse(bh);
850 continue;
851 }
852
853 err = scan_revoke_records(journal, bh,
854 next_commit_ID, info);
855 brelse(bh);
856 if (err)
857 goto failed;
858 continue;
859
860 default:
861 jbd2_debug(3, "Unrecognised magic %d, end of scan.\n",
862 blocktype);
863 brelse(bh);
864 goto done;
865 }
866 }
867
868 done:
869 /*
870 * We broke out of the log scan loop: either we came to the
871 * known end of the log or we found an unexpected block in the
872 * log. If the latter happened, then we know that the "current"
873 * transaction marks the end of the valid log.
874 */
875
876 if (pass == PASS_SCAN) {
877 if (!info->end_transaction)
878 info->end_transaction = next_commit_ID;
879 if (!info->head_block)
880 info->head_block = head_block;
881 } else {
882 /* It's really bad news if different passes end up at
883 * different places (but possible due to IO errors). */
884 if (info->end_transaction != next_commit_ID) {
885 printk(KERN_ERR "JBD2: recovery pass %d ended at "
886 "transaction %u, expected %u\n",
887 pass, next_commit_ID, info->end_transaction);
888 if (!success)
889 success = -EIO;
890 }
891 }
892
893 if (jbd2_has_feature_fast_commit(journal) && pass != PASS_REVOKE) {
894 err = fc_do_one_pass(journal, info, pass);
895 if (err)
896 success = err;
897 }
898
899 if (block_error && success == 0)
900 success = -EIO;
901 return success;
902
903 failed:
904 return err;
905}
906
907/* Scan a revoke record, marking all blocks mentioned as revoked. */
908
909static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
910 tid_t sequence, struct recovery_info *info)
911{
912 jbd2_journal_revoke_header_t *header;
913 int offset, max;
914 unsigned csum_size = 0;
915 __u32 rcount;
916 int record_len = 4;
917
918 header = (jbd2_journal_revoke_header_t *) bh->b_data;
919 offset = sizeof(jbd2_journal_revoke_header_t);
920 rcount = be32_to_cpu(header->r_count);
921
922 if (jbd2_journal_has_csum_v2or3(journal))
923 csum_size = sizeof(struct jbd2_journal_block_tail);
924 if (rcount > journal->j_blocksize - csum_size)
925 return -EINVAL;
926 max = rcount;
927
928 if (jbd2_has_feature_64bit(journal))
929 record_len = 8;
930
931 while (offset + record_len <= max) {
932 unsigned long long blocknr;
933 int err;
934
935 if (record_len == 4)
936 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
937 else
938 blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset)));
939 offset += record_len;
940 err = jbd2_journal_set_revoke(journal, blocknr, sequence);
941 if (err)
942 return err;
943 ++info->nr_revokes;
944 }
945 return 0;
946}