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Merge branch 'drm-fixes' of git://people.freedesktop.org/~airlied/linux
[linux-2.6.git] / fs / jbd2 / recovery.c
blobd4851464b57e5ab4aac7e5851f457c796c244795
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 */
31 struct 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
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 *);
46
47 #ifdef __KERNEL__
48
49 /* Release readahead buffers after use */
50 static 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
70 static 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
119 failed:
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
132 static 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
177 static 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
201 static 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) \
231 do { \
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 */
248 int 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 err2 = blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
294 if (!err)
295 err = err2;
296 }
297 return err;
298 }
299
300 /**
301 * jbd2_journal_skip_recovery - Start journal and wipe exiting records
302 * @journal: journal to startup
303 *
304 * Locate any valid recovery information from the journal and set up the
305 * journal structures in memory to ignore it (presumably because the
306 * caller has evidence that it is out of date).
307 * This function does'nt appear to be exorted..
308 *
309 * We perform one pass over the journal to allow us to tell the user how
310 * much recovery information is being erased, and to let us initialise
311 * the journal transaction sequence numbers to the next unused ID.
312 */
313 int jbd2_journal_skip_recovery(journal_t *journal)
314 {
315 int err;
316
317 struct recovery_info info;
318
319 memset (&info, 0, sizeof(info));
320
321 err = do_one_pass(journal, &info, PASS_SCAN);
322
323 if (err) {
324 printk(KERN_ERR "JBD2: error %d scanning journal\n", err);
325 ++journal->j_transaction_sequence;
326 } else {
327 #ifdef CONFIG_JBD2_DEBUG
328 int dropped = info.end_transaction -
329 be32_to_cpu(journal->j_superblock->s_sequence);
330 jbd_debug(1,
331 "JBD2: ignoring %d transaction%s from the journal.\n",
332 dropped, (dropped == 1) ? "" : "s");
333 #endif
334 journal->j_transaction_sequence = ++info.end_transaction;
335 }
336
337 journal->j_tail = 0;
338 return err;
339 }
340
341 static inline unsigned long long read_tag_block(int tag_bytes, journal_block_tag_t *tag)
342 {
343 unsigned long long block = be32_to_cpu(tag->t_blocknr);
344 if (tag_bytes > JBD2_TAG_SIZE32)
345 block |= (u64)be32_to_cpu(tag->t_blocknr_high) << 32;
346 return block;
347 }
348
349 /*
350 * calc_chksums calculates the checksums for the blocks described in the
351 * descriptor block.
352 */
353 static int calc_chksums(journal_t *journal, struct buffer_head *bh,
354 unsigned long *next_log_block, __u32 *crc32_sum)
355 {
356 int i, num_blks, err;
357 unsigned long io_block;
358 struct buffer_head *obh;
359
360 num_blks = count_tags(journal, bh);
361 /* Calculate checksum of the descriptor block. */
362 *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size);
363
364 for (i = 0; i < num_blks; i++) {
365 io_block = (*next_log_block)++;
366 wrap(journal, *next_log_block);
367 err = jread(&obh, journal, io_block);
368 if (err) {
369 printk(KERN_ERR "JBD2: IO error %d recovering block "
370 "%lu in log\n", err, io_block);
371 return 1;
372 } else {
373 *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data,
374 obh->b_size);
375 }
376 put_bh(obh);
377 }
378 return 0;
379 }
380
381 static int jbd2_commit_block_csum_verify(journal_t *j, void *buf)
382 {
383 struct commit_header *h;
384 __u32 provided, calculated;
385
386 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
387 return 1;
388
389 h = buf;
390 provided = h->h_chksum[0];
391 h->h_chksum[0] = 0;
392 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
393 h->h_chksum[0] = provided;
394
395 provided = be32_to_cpu(provided);
396 return provided == calculated;
397 }
398
399 static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag,
400 void *buf, __u32 sequence)
401 {
402 __u32 csum32;
403
404 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
405 return 1;
406
407 sequence = cpu_to_be32(sequence);
408 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&sequence,
409 sizeof(sequence));
410 csum32 = jbd2_chksum(j, csum32, buf, j->j_blocksize);
411
412 return tag->t_checksum == cpu_to_be16(csum32);
413 }
414
415 static int do_one_pass(journal_t *journal,
416 struct recovery_info *info, enum passtype pass)
417 {
418 unsigned int first_commit_ID, next_commit_ID;
419 unsigned long next_log_block;
420 int err, success = 0;
421 journal_superblock_t * sb;
422 journal_header_t * tmp;
423 struct buffer_head * bh;
424 unsigned int sequence;
425 int blocktype;
426 int tag_bytes = journal_tag_bytes(journal);
427 __u32 crc32_sum = ~0; /* Transactional Checksums */
428 int descr_csum_size = 0;
429
430 /*
431 * First thing is to establish what we expect to find in the log
432 * (in terms of transaction IDs), and where (in terms of log
433 * block offsets): query the superblock.
434 */
435
436 sb = journal->j_superblock;
437 next_commit_ID = be32_to_cpu(sb->s_sequence);
438 next_log_block = be32_to_cpu(sb->s_start);
439
440 first_commit_ID = next_commit_ID;
441 if (pass == PASS_SCAN)
442 info->start_transaction = first_commit_ID;
443
444 jbd_debug(1, "Starting recovery pass %d\n", pass);
445
446 /*
447 * Now we walk through the log, transaction by transaction,
448 * making sure that each transaction has a commit block in the
449 * expected place. Each complete transaction gets replayed back
450 * into the main filesystem.
451 */
452
453 while (1) {
454 int flags;
455 char * tagp;
456 journal_block_tag_t * tag;
457 struct buffer_head * obh;
458 struct buffer_head * nbh;
459
460 cond_resched();
461
462 /* If we already know where to stop the log traversal,
463 * check right now that we haven't gone past the end of
464 * the log. */
465
466 if (pass != PASS_SCAN)
467 if (tid_geq(next_commit_ID, info->end_transaction))
468 break;
469
470 jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
471 next_commit_ID, next_log_block, journal->j_last);
472
473 /* Skip over each chunk of the transaction looking
474 * either the next descriptor block or the final commit
475 * record. */
476
477 jbd_debug(3, "JBD2: checking block %ld\n", next_log_block);
478 err = jread(&bh, journal, next_log_block);
479 if (err)
480 goto failed;
481
482 next_log_block++;
483 wrap(journal, next_log_block);
484
485 /* What kind of buffer is it?
486 *
487 * If it is a descriptor block, check that it has the
488 * expected sequence number. Otherwise, we're all done
489 * here. */
490
491 tmp = (journal_header_t *)bh->b_data;
492
493 if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) {
494 brelse(bh);
495 break;
496 }
497
498 blocktype = be32_to_cpu(tmp->h_blocktype);
499 sequence = be32_to_cpu(tmp->h_sequence);
500 jbd_debug(3, "Found magic %d, sequence %d\n",
501 blocktype, sequence);
502
503 if (sequence != next_commit_ID) {
504 brelse(bh);
505 break;
506 }
507
508 /* OK, we have a valid descriptor block which matches
509 * all of the sequence number checks. What are we going
510 * to do with it? That depends on the pass... */
511
512 switch(blocktype) {
513 case JBD2_DESCRIPTOR_BLOCK:
514 /* Verify checksum first */
515 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
516 JBD2_FEATURE_INCOMPAT_CSUM_V2))
517 descr_csum_size =
518 sizeof(struct jbd2_journal_block_tail);
519 if (descr_csum_size > 0 &&
520 !jbd2_descr_block_csum_verify(journal,
521 bh->b_data)) {
522 err = -EIO;
523 goto failed;
524 }
525
526 /* If it is a valid descriptor block, replay it
527 * in pass REPLAY; if journal_checksums enabled, then
528 * calculate checksums in PASS_SCAN, otherwise,
529 * just skip over the blocks it describes. */
530 if (pass != PASS_REPLAY) {
531 if (pass == PASS_SCAN &&
532 JBD2_HAS_COMPAT_FEATURE(journal,
533 JBD2_FEATURE_COMPAT_CHECKSUM) &&
534 !info->end_transaction) {
535 if (calc_chksums(journal, bh,
536 &next_log_block,
537 &crc32_sum)) {
538 put_bh(bh);
539 break;
540 }
541 put_bh(bh);
542 continue;
543 }
544 next_log_block += count_tags(journal, bh);
545 wrap(journal, next_log_block);
546 put_bh(bh);
547 continue;
548 }
549
550 /* A descriptor block: we can now write all of
551 * the data blocks. Yay, useful work is finally
552 * getting done here! */
553
554 tagp = &bh->b_data[sizeof(journal_header_t)];
555 while ((tagp - bh->b_data + tag_bytes)
556 <= journal->j_blocksize - descr_csum_size) {
557 unsigned long io_block;
558
559 tag = (journal_block_tag_t *) tagp;
560 flags = be16_to_cpu(tag->t_flags);
561
562 io_block = next_log_block++;
563 wrap(journal, next_log_block);
564 err = jread(&obh, journal, io_block);
565 if (err) {
566 /* Recover what we can, but
567 * report failure at the end. */
568 success = err;
569 printk(KERN_ERR
570 "JBD2: IO error %d recovering "
571 "block %ld in log\n",
572 err, io_block);
573 } else {
574 unsigned long long blocknr;
575
576 J_ASSERT(obh != NULL);
577 blocknr = read_tag_block(tag_bytes,
578 tag);
579
580 /* If the block has been
581 * revoked, then we're all done
582 * here. */
583 if (jbd2_journal_test_revoke
584 (journal, blocknr,
585 next_commit_ID)) {
586 brelse(obh);
587 ++info->nr_revoke_hits;
588 goto skip_write;
589 }
590
591 /* Look for block corruption */
592 if (!jbd2_block_tag_csum_verify(
593 journal, tag, obh->b_data,
594 be32_to_cpu(tmp->h_sequence))) {
595 brelse(obh);
596 success = -EIO;
597 printk(KERN_ERR "JBD: Invalid "
598 "checksum recovering "
599 "block %llu in log\n",
600 blocknr);
601 continue;
602 }
603
604 /* Find a buffer for the new
605 * data being restored */
606 nbh = __getblk(journal->j_fs_dev,
607 blocknr,
608 journal->j_blocksize);
609 if (nbh == NULL) {
610 printk(KERN_ERR
611 "JBD2: Out of memory "
612 "during recovery.\n");
613 err = -ENOMEM;
614 brelse(bh);
615 brelse(obh);
616 goto failed;
617 }
618
619 lock_buffer(nbh);
620 memcpy(nbh->b_data, obh->b_data,
621 journal->j_blocksize);
622 if (flags & JBD2_FLAG_ESCAPE) {
623 *((__be32 *)nbh->b_data) =
624 cpu_to_be32(JBD2_MAGIC_NUMBER);
625 }
626
627 BUFFER_TRACE(nbh, "marking dirty");
628 set_buffer_uptodate(nbh);
629 mark_buffer_dirty(nbh);
630 BUFFER_TRACE(nbh, "marking uptodate");
631 ++info->nr_replays;
632 /* ll_rw_block(WRITE, 1, &nbh); */
633 unlock_buffer(nbh);
634 brelse(obh);
635 brelse(nbh);
636 }
637
638 skip_write:
639 tagp += tag_bytes;
640 if (!(flags & JBD2_FLAG_SAME_UUID))
641 tagp += 16;
642
643 if (flags & JBD2_FLAG_LAST_TAG)
644 break;
645 }
646
647 brelse(bh);
648 continue;
649
650 case JBD2_COMMIT_BLOCK:
651 /* How to differentiate between interrupted commit
652 * and journal corruption ?
653 *
654 * {nth transaction}
655 * Checksum Verification Failed
656 * |
657 * ____________________
658 * | |
659 * async_commit sync_commit
660 * | |
661 * | GO TO NEXT "Journal Corruption"
662 * | TRANSACTION
663 * |
664 * {(n+1)th transanction}
665 * |
666 * _______|______________
667 * | |
668 * Commit block found Commit block not found
669 * | |
670 * "Journal Corruption" |
671 * _____________|_________
672 * | |
673 * nth trans corrupt OR nth trans
674 * and (n+1)th interrupted interrupted
675 * before commit block
676 * could reach the disk.
677 * (Cannot find the difference in above
678 * mentioned conditions. Hence assume
679 * "Interrupted Commit".)
680 */
681
682 /* Found an expected commit block: if checksums
683 * are present verify them in PASS_SCAN; else not
684 * much to do other than move on to the next sequence
685 * number. */
686 if (pass == PASS_SCAN &&
687 JBD2_HAS_COMPAT_FEATURE(journal,
688 JBD2_FEATURE_COMPAT_CHECKSUM)) {
689 int chksum_err, chksum_seen;
690 struct commit_header *cbh =
691 (struct commit_header *)bh->b_data;
692 unsigned found_chksum =
693 be32_to_cpu(cbh->h_chksum[0]);
694
695 chksum_err = chksum_seen = 0;
696
697 if (info->end_transaction) {
698 journal->j_failed_commit =
699 info->end_transaction;
700 brelse(bh);
701 break;
702 }
703
704 if (crc32_sum == found_chksum &&
705 cbh->h_chksum_type == JBD2_CRC32_CHKSUM &&
706 cbh->h_chksum_size ==
707 JBD2_CRC32_CHKSUM_SIZE)
708 chksum_seen = 1;
709 else if (!(cbh->h_chksum_type == 0 &&
710 cbh->h_chksum_size == 0 &&
711 found_chksum == 0 &&
712 !chksum_seen))
713 /*
714 * If fs is mounted using an old kernel and then
715 * kernel with journal_chksum is used then we
716 * get a situation where the journal flag has
717 * checksum flag set but checksums are not
718 * present i.e chksum = 0, in the individual
719 * commit blocks.
720 * Hence to avoid checksum failures, in this
721 * situation, this extra check is added.
722 */
723 chksum_err = 1;
724
725 if (chksum_err) {
726 info->end_transaction = next_commit_ID;
727
728 if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
729 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)){
730 journal->j_failed_commit =
731 next_commit_ID;
732 brelse(bh);
733 break;
734 }
735 }
736 crc32_sum = ~0;
737 }
738 if (pass == PASS_SCAN &&
739 !jbd2_commit_block_csum_verify(journal,
740 bh->b_data)) {
741 info->end_transaction = next_commit_ID;
742
743 if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
744 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
745 journal->j_failed_commit =
746 next_commit_ID;
747 brelse(bh);
748 break;
749 }
750 }
751 brelse(bh);
752 next_commit_ID++;
753 continue;
754
755 case JBD2_REVOKE_BLOCK:
756 /* If we aren't in the REVOKE pass, then we can
757 * just skip over this block. */
758 if (pass != PASS_REVOKE) {
759 brelse(bh);
760 continue;
761 }
762
763 err = scan_revoke_records(journal, bh,
764 next_commit_ID, info);
765 brelse(bh);
766 if (err)
767 goto failed;
768 continue;
769
770 default:
771 jbd_debug(3, "Unrecognised magic %d, end of scan.\n",
772 blocktype);
773 brelse(bh);
774 goto done;
775 }
776 }
777
778 done:
779 /*
780 * We broke out of the log scan loop: either we came to the
781 * known end of the log or we found an unexpected block in the
782 * log. If the latter happened, then we know that the "current"
783 * transaction marks the end of the valid log.
784 */
785
786 if (pass == PASS_SCAN) {
787 if (!info->end_transaction)
788 info->end_transaction = next_commit_ID;
789 } else {
790 /* It's really bad news if different passes end up at
791 * different places (but possible due to IO errors). */
792 if (info->end_transaction != next_commit_ID) {
793 printk(KERN_ERR "JBD2: recovery pass %d ended at "
794 "transaction %u, expected %u\n",
795 pass, next_commit_ID, info->end_transaction);
796 if (!success)
797 success = -EIO;
798 }
799 }
800
801 return success;
802
803 failed:
804 return err;
805 }
806
807 static int jbd2_revoke_block_csum_verify(journal_t *j,
808 void *buf)
809 {
810 struct jbd2_journal_revoke_tail *tail;
811 __u32 provided, calculated;
812
813 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
814 return 1;
815
816 tail = (struct jbd2_journal_revoke_tail *)(buf + j->j_blocksize -
817 sizeof(struct jbd2_journal_revoke_tail));
818 provided = tail->r_checksum;
819 tail->r_checksum = 0;
820 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
821 tail->r_checksum = provided;
822
823 provided = be32_to_cpu(provided);
824 return provided == calculated;
825 }
826
827 /* Scan a revoke record, marking all blocks mentioned as revoked. */
828
829 static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
830 tid_t sequence, struct recovery_info *info)
831 {
832 jbd2_journal_revoke_header_t *header;
833 int offset, max;
834 int record_len = 4;
835
836 header = (jbd2_journal_revoke_header_t *) bh->b_data;
837 offset = sizeof(jbd2_journal_revoke_header_t);
838 max = be32_to_cpu(header->r_count);
839
840 if (!jbd2_revoke_block_csum_verify(journal, header))
841 return -EINVAL;
842
843 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
844 record_len = 8;
845
846 while (offset + record_len <= max) {
847 unsigned long long blocknr;
848 int err;
849
850 if (record_len == 4)
851 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
852 else
853 blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset)));
854 offset += record_len;
855 err = jbd2_journal_set_revoke(journal, blocknr, sequence);
856 if (err)
857 return err;
858 ++info->nr_revokes;
859 }
860 return 0;
861 }
Linus' kernel tree