2 * linux/fs/jbd2/recovery.c
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1999
6 * Copyright 1999-2000 Red Hat Software --- All Rights Reserved
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.
12 * Journal recovery routines for the generic filesystem journaling code;
13 * part of the ext2fs journaling system.
19 #include <linux/time.h>
21 #include <linux/jbd2.h>
22 #include <linux/errno.h>
23 #include <linux/crc32.h>
24 #include <linux/blkdev.h>
28 * Maintain information about the progress of the recovery job, so that
29 * the different passes can carry information between them.
33 tid_t start_transaction
;
34 tid_t end_transaction
;
41 enum passtype
{PASS_SCAN
, PASS_REVOKE
, PASS_REPLAY
};
42 static int do_one_pass(journal_t
*journal
,
43 struct recovery_info
*info
, enum passtype pass
);
44 static int scan_revoke_records(journal_t
*, struct buffer_head
*,
45 tid_t
, struct recovery_info
*);
49 /* Release readahead buffers after use */
50 static void journal_brelse_array(struct buffer_head
*b
[], int n
)
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.
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
70 static int do_readahead(journal_t
*journal
, unsigned int start
)
73 unsigned int max
, nbufs
, next
;
74 unsigned long long blocknr
;
75 struct buffer_head
*bh
;
77 struct buffer_head
* bufs
[MAXBUF
];
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
;
84 /* Do the readahead itself. We'll submit MAXBUF buffer_heads at
85 * a time to the block device IO layer. */
89 for (next
= start
; next
< max
; next
++) {
90 err
= jbd2_journal_bmap(journal
, next
, &blocknr
);
93 printk(KERN_ERR
"JBD2: bad block at offset %u\n",
98 bh
= __getblk(journal
->j_dev
, blocknr
, journal
->j_blocksize
);
104 if (!buffer_uptodate(bh
) && !buffer_locked(bh
)) {
106 if (nbufs
== MAXBUF
) {
107 ll_rw_block(READ
, nbufs
, bufs
);
108 journal_brelse_array(bufs
, nbufs
);
116 ll_rw_block(READ
, nbufs
, bufs
);
121 journal_brelse_array(bufs
, nbufs
);
125 #endif /* __KERNEL__ */
129 * Read a block from the journal
132 static int jread(struct buffer_head
**bhp
, journal_t
*journal
,
136 unsigned long long blocknr
;
137 struct buffer_head
*bh
;
141 if (offset
>= journal
->j_maxlen
) {
142 printk(KERN_ERR
"JBD2: corrupted journal superblock\n");
146 err
= jbd2_journal_bmap(journal
, offset
, &blocknr
);
149 printk(KERN_ERR
"JBD2: bad block at offset %u\n",
154 bh
= __getblk(journal
->j_dev
, blocknr
, journal
->j_blocksize
);
158 if (!buffer_uptodate(bh
)) {
159 /* If this is a brand new buffer, start readahead.
160 Otherwise, we assume we are already reading it. */
162 do_readahead(journal
, offset
);
166 if (!buffer_uptodate(bh
)) {
167 printk(KERN_ERR
"JBD2: Failed to read block at offset %u\n",
177 static int jbd2_descr_block_csum_verify(journal_t
*j
,
180 struct jbd2_journal_block_tail
*tail
;
181 __u32 provided
, calculated
;
183 if (!JBD2_HAS_INCOMPAT_FEATURE(j
, JBD2_FEATURE_INCOMPAT_CSUM_V2
))
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
;
193 provided
= be32_to_cpu(provided
);
194 return provided
== calculated
;
198 * Count the number of in-use tags in a journal descriptor block.
201 static int count_tags(journal_t
*journal
, struct buffer_head
*bh
)
204 journal_block_tag_t
* tag
;
205 int nr
= 0, size
= journal
->j_blocksize
;
206 int tag_bytes
= journal_tag_bytes(journal
);
208 if (JBD2_HAS_INCOMPAT_FEATURE(journal
, JBD2_FEATURE_INCOMPAT_CSUM_V2
))
209 size
-= sizeof(struct jbd2_journal_block_tail
);
211 tagp
= &bh
->b_data
[sizeof(journal_header_t
)];
213 while ((tagp
- bh
->b_data
+ tag_bytes
) <= size
) {
214 tag
= (journal_block_tag_t
*) tagp
;
218 if (!(tag
->t_flags
& cpu_to_be16(JBD2_FLAG_SAME_UUID
)))
221 if (tag
->t_flags
& cpu_to_be16(JBD2_FLAG_LAST_TAG
))
229 /* Make sure we wrap around the log correctly! */
230 #define wrap(journal, var) \
232 if (var >= (journal)->j_last) \
233 var -= ((journal)->j_last - (journal)->j_first); \
237 * jbd2_journal_recover - recovers a on-disk journal
238 * @journal: the journal to recover
240 * The primary function for recovering the log contents when mounting a
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
248 int jbd2_journal_recover(journal_t
*journal
)
251 journal_superblock_t
* sb
;
253 struct recovery_info info
;
255 memset(&info
, 0, sizeof(info
));
256 sb
= journal
->j_superblock
;
259 * The journal superblock's s_start field (the current log head)
260 * is always zero if, and only if, the journal was cleanly
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;
271 err
= do_one_pass(journal
, &info
, PASS_SCAN
);
273 err
= do_one_pass(journal
, &info
, PASS_REVOKE
);
275 err
= do_one_pass(journal
, &info
, PASS_REPLAY
);
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
);
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
;
287 jbd2_journal_clear_revoke(journal
);
288 err2
= sync_blockdev(journal
->j_fs_dev
);
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
);
298 * jbd2_journal_skip_recovery - Start journal and wipe exiting records
299 * @journal: journal to startup
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..
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.
310 int jbd2_journal_skip_recovery(journal_t
*journal
)
314 struct recovery_info info
;
316 memset (&info
, 0, sizeof(info
));
318 err
= do_one_pass(journal
, &info
, PASS_SCAN
);
321 printk(KERN_ERR
"JBD2: error %d scanning journal\n", err
);
322 ++journal
->j_transaction_sequence
;
324 #ifdef CONFIG_JBD2_DEBUG
325 int dropped
= info
.end_transaction
-
326 be32_to_cpu(journal
->j_superblock
->s_sequence
);
328 "JBD2: ignoring %d transaction%s from the journal.\n",
329 dropped
, (dropped
== 1) ? "" : "s");
331 journal
->j_transaction_sequence
= ++info
.end_transaction
;
338 static inline unsigned long long read_tag_block(int tag_bytes
, journal_block_tag_t
*tag
)
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;
347 * calc_chksums calculates the checksums for the blocks described in the
350 static int calc_chksums(journal_t
*journal
, struct buffer_head
*bh
,
351 unsigned long *next_log_block
, __u32
*crc32_sum
)
353 int i
, num_blks
, err
;
354 unsigned long io_block
;
355 struct buffer_head
*obh
;
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
);
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
);
366 printk(KERN_ERR
"JBD2: IO error %d recovering block "
367 "%lu in log\n", err
, io_block
);
370 *crc32_sum
= crc32_be(*crc32_sum
, (void *)obh
->b_data
,
378 static int jbd2_commit_block_csum_verify(journal_t
*j
, void *buf
)
380 struct commit_header
*h
;
381 __u32 provided
, calculated
;
383 if (!JBD2_HAS_INCOMPAT_FEATURE(j
, JBD2_FEATURE_INCOMPAT_CSUM_V2
))
387 provided
= h
->h_chksum
[0];
389 calculated
= jbd2_chksum(j
, j
->j_csum_seed
, buf
, j
->j_blocksize
);
390 h
->h_chksum
[0] = provided
;
392 provided
= be32_to_cpu(provided
);
393 return provided
== calculated
;
396 static int jbd2_block_tag_csum_verify(journal_t
*j
, journal_block_tag_t
*tag
,
397 void *buf
, __u32 sequence
)
399 __u32 provided
, calculated
;
401 if (!JBD2_HAS_INCOMPAT_FEATURE(j
, JBD2_FEATURE_INCOMPAT_CSUM_V2
))
404 sequence
= cpu_to_be32(sequence
);
405 calculated
= jbd2_chksum(j
, j
->j_csum_seed
, (__u8
*)&sequence
,
407 calculated
= jbd2_chksum(j
, calculated
, buf
, j
->j_blocksize
);
408 provided
= be32_to_cpu(tag
->t_checksum
);
410 return provided
== cpu_to_be32(calculated
);
413 static int do_one_pass(journal_t
*journal
,
414 struct recovery_info
*info
, enum passtype pass
)
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
;
424 int tag_bytes
= journal_tag_bytes(journal
);
425 __u32 crc32_sum
= ~0; /* Transactional Checksums */
426 int descr_csum_size
= 0;
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.
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
);
438 first_commit_ID
= next_commit_ID
;
439 if (pass
== PASS_SCAN
)
440 info
->start_transaction
= first_commit_ID
;
442 jbd_debug(1, "Starting recovery pass %d\n", pass
);
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.
454 journal_block_tag_t
* tag
;
455 struct buffer_head
* obh
;
456 struct buffer_head
* nbh
;
460 /* If we already know where to stop the log traversal,
461 * check right now that we haven't gone past the end of
464 if (pass
!= PASS_SCAN
)
465 if (tid_geq(next_commit_ID
, info
->end_transaction
))
468 jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
469 next_commit_ID
, next_log_block
, journal
->j_last
);
471 /* Skip over each chunk of the transaction looking
472 * either the next descriptor block or the final commit
475 jbd_debug(3, "JBD2: checking block %ld\n", next_log_block
);
476 err
= jread(&bh
, journal
, next_log_block
);
481 wrap(journal
, next_log_block
);
483 /* What kind of buffer is it?
485 * If it is a descriptor block, check that it has the
486 * expected sequence number. Otherwise, we're all done
489 tmp
= (journal_header_t
*)bh
->b_data
;
491 if (tmp
->h_magic
!= cpu_to_be32(JBD2_MAGIC_NUMBER
)) {
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
);
501 if (sequence
!= next_commit_ID
) {
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... */
511 case JBD2_DESCRIPTOR_BLOCK
:
512 /* Verify checksum first */
513 if (JBD2_HAS_INCOMPAT_FEATURE(journal
,
514 JBD2_FEATURE_INCOMPAT_CSUM_V2
))
516 sizeof(struct jbd2_journal_block_tail
);
517 if (descr_csum_size
> 0 &&
518 !jbd2_descr_block_csum_verify(journal
,
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
,
542 next_log_block
+= count_tags(journal
, bh
);
543 wrap(journal
, next_log_block
);
548 /* A descriptor block: we can now write all of
549 * the data blocks. Yay, useful work is finally
550 * getting done here! */
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
;
557 tag
= (journal_block_tag_t
*) tagp
;
558 flags
= be16_to_cpu(tag
->t_flags
);
560 io_block
= next_log_block
++;
561 wrap(journal
, next_log_block
);
562 err
= jread(&obh
, journal
, io_block
);
564 /* Recover what we can, but
565 * report failure at the end. */
568 "JBD2: IO error %d recovering "
569 "block %ld in log\n",
572 unsigned long long blocknr
;
574 J_ASSERT(obh
!= NULL
);
575 blocknr
= read_tag_block(tag_bytes
,
578 /* If the block has been
579 * revoked, then we're all done
581 if (jbd2_journal_test_revoke
585 ++info
->nr_revoke_hits
;
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
))) {
595 printk(KERN_ERR
"JBD: Invalid "
596 "checksum recovering "
597 "block %llu in log\n",
602 /* Find a buffer for the new
603 * data being restored */
604 nbh
= __getblk(journal
->j_fs_dev
,
606 journal
->j_blocksize
);
609 "JBD2: Out of memory "
610 "during recovery.\n");
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
);
625 BUFFER_TRACE(nbh
, "marking dirty");
626 set_buffer_uptodate(nbh
);
627 mark_buffer_dirty(nbh
);
628 BUFFER_TRACE(nbh
, "marking uptodate");
630 /* ll_rw_block(WRITE, 1, &nbh); */
638 if (!(flags
& JBD2_FLAG_SAME_UUID
))
641 if (flags
& JBD2_FLAG_LAST_TAG
)
648 case JBD2_COMMIT_BLOCK
:
649 /* How to differentiate between interrupted commit
650 * and journal corruption ?
653 * Checksum Verification Failed
655 * ____________________
657 * async_commit sync_commit
659 * | GO TO NEXT "Journal Corruption"
662 * {(n+1)th transanction}
664 * _______|______________
666 * Commit block found Commit block not found
668 * "Journal Corruption" |
669 * _____________|_________
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".)
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
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]);
693 chksum_err
= chksum_seen
= 0;
695 if (info
->end_transaction
) {
696 journal
->j_failed_commit
=
697 info
->end_transaction
;
702 if (crc32_sum
== found_chksum
&&
703 cbh
->h_chksum_type
== JBD2_CRC32_CHKSUM
&&
704 cbh
->h_chksum_size
==
705 JBD2_CRC32_CHKSUM_SIZE
)
707 else if (!(cbh
->h_chksum_type
== 0 &&
708 cbh
->h_chksum_size
== 0 &&
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
718 * Hence to avoid checksum failures, in this
719 * situation, this extra check is added.
724 info
->end_transaction
= next_commit_ID
;
726 if (!JBD2_HAS_INCOMPAT_FEATURE(journal
,
727 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT
)){
728 journal
->j_failed_commit
=
736 if (pass
== PASS_SCAN
&&
737 !jbd2_commit_block_csum_verify(journal
,
739 info
->end_transaction
= next_commit_ID
;
741 if (!JBD2_HAS_INCOMPAT_FEATURE(journal
,
742 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT
)) {
743 journal
->j_failed_commit
=
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
) {
761 err
= scan_revoke_records(journal
, bh
,
762 next_commit_ID
, info
);
769 jbd_debug(3, "Unrecognised magic %d, end of scan.\n",
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.
784 if (pass
== PASS_SCAN
) {
785 if (!info
->end_transaction
)
786 info
->end_transaction
= next_commit_ID
;
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
);
805 static int jbd2_revoke_block_csum_verify(journal_t
*j
,
808 struct jbd2_journal_revoke_tail
*tail
;
809 __u32 provided
, calculated
;
811 if (!JBD2_HAS_INCOMPAT_FEATURE(j
, JBD2_FEATURE_INCOMPAT_CSUM_V2
))
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
;
821 provided
= be32_to_cpu(provided
);
822 return provided
== calculated
;
825 /* Scan a revoke record, marking all blocks mentioned as revoked. */
827 static int scan_revoke_records(journal_t
*journal
, struct buffer_head
*bh
,
828 tid_t sequence
, struct recovery_info
*info
)
830 jbd2_journal_revoke_header_t
*header
;
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
);
838 if (!jbd2_revoke_block_csum_verify(journal
, header
))
841 if (JBD2_HAS_INCOMPAT_FEATURE(journal
, JBD2_FEATURE_INCOMPAT_64BIT
))
844 while (offset
+ record_len
<= max
) {
845 unsigned long long blocknr
;
849 blocknr
= be32_to_cpu(* ((__be32
*) (bh
->b_data
+offset
)));
851 blocknr
= be64_to_cpu(* ((__be64
*) (bh
->b_data
+offset
)));
852 offset
+= record_len
;
853 err
= jbd2_journal_set_revoke(journal
, blocknr
, sequence
);