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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 #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 -EFSCORRUPTED;
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 __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 *)(buf + j->j_blocksize -
188 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
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_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 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 doesn't appear to be exported..
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(journal_t *journal,
342 journal_block_tag_t *tag)
343 {
344 unsigned long long block = be32_to_cpu(tag->t_blocknr);
345 if (jbd2_has_feature_64bit(journal))
346 block |= (u64)be32_to_cpu(tag->t_blocknr_high) << 32;
347 return block;
348 }
349
350 /*
351 * calc_chksums calculates the checksums for the blocks described in the
352 * descriptor block.
353 */
354 static int calc_chksums(journal_t *journal, struct buffer_head *bh,
355 unsigned long *next_log_block, __u32 *crc32_sum)
356 {
357 int i, num_blks, err;
358 unsigned long io_block;
359 struct buffer_head *obh;
360
361 num_blks = count_tags(journal, bh);
362 /* Calculate checksum of the descriptor block. */
363 *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size);
364
365 for (i = 0; i < num_blks; i++) {
366 io_block = (*next_log_block)++;
367 wrap(journal, *next_log_block);
368 err = jread(&obh, journal, io_block);
369 if (err) {
370 printk(KERN_ERR "JBD2: IO error %d recovering block "
371 "%lu in log\n", err, io_block);
372 return 1;
373 } else {
374 *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data,
375 obh->b_size);
376 }
377 put_bh(obh);
378 }
379 return 0;
380 }
381
382 static int jbd2_commit_block_csum_verify(journal_t *j, void *buf)
383 {
384 struct commit_header *h;
385 __be32 provided;
386 __u32 calculated;
387
388 if (!jbd2_journal_has_csum_v2or3(j))
389 return 1;
390
391 h = buf;
392 provided = h->h_chksum[0];
393 h->h_chksum[0] = 0;
394 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
395 h->h_chksum[0] = provided;
396
397 return provided == cpu_to_be32(calculated);
398 }
399
400 static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag,
401 void *buf, __u32 sequence)
402 {
403 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
404 __u32 csum32;
405 __be32 seq;
406
407 if (!jbd2_journal_has_csum_v2or3(j))
408 return 1;
409
410 seq = cpu_to_be32(sequence);
411 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
412 csum32 = jbd2_chksum(j, csum32, buf, j->j_blocksize);
413
414 if (jbd2_has_feature_csum3(j))
415 return tag3->t_checksum == cpu_to_be32(csum32);
416 else
417 return tag->t_checksum == cpu_to_be16(csum32);
418 }
419
420 static int do_one_pass(journal_t *journal,
421 struct recovery_info *info, enum passtype pass)
422 {
423 unsigned int first_commit_ID, next_commit_ID;
424 unsigned long next_log_block;
425 int err, success = 0;
426 journal_superblock_t * sb;
427 journal_header_t * tmp;
428 struct buffer_head * bh;
429 unsigned int sequence;
430 int blocktype;
431 int tag_bytes = journal_tag_bytes(journal);
432 __u32 crc32_sum = ~0; /* Transactional Checksums */
433 int descr_csum_size = 0;
434 int block_error = 0;
435
436 /*
437 * First thing is to establish what we expect to find in the log
438 * (in terms of transaction IDs), and where (in terms of log
439 * block offsets): query the superblock.
440 */
441
442 sb = journal->j_superblock;
443 next_commit_ID = be32_to_cpu(sb->s_sequence);
444 next_log_block = be32_to_cpu(sb->s_start);
445
446 first_commit_ID = next_commit_ID;
447 if (pass == PASS_SCAN)
448 info->start_transaction = first_commit_ID;
449
450 jbd_debug(1, "Starting recovery pass %d\n", pass);
451
452 /*
453 * Now we walk through the log, transaction by transaction,
454 * making sure that each transaction has a commit block in the
455 * expected place. Each complete transaction gets replayed back
456 * into the main filesystem.
457 */
458
459 while (1) {
460 int flags;
461 char * tagp;
462 journal_block_tag_t * tag;
463 struct buffer_head * obh;
464 struct buffer_head * nbh;
465
466 cond_resched();
467
468 /* If we already know where to stop the log traversal,
469 * check right now that we haven't gone past the end of
470 * the log. */
471
472 if (pass != PASS_SCAN)
473 if (tid_geq(next_commit_ID, info->end_transaction))
474 break;
475
476 jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
477 next_commit_ID, next_log_block, journal->j_last);
478
479 /* Skip over each chunk of the transaction looking
480 * either the next descriptor block or the final commit
481 * record. */
482
483 jbd_debug(3, "JBD2: checking block %ld\n", next_log_block);
484 err = jread(&bh, journal, next_log_block);
485 if (err)
486 goto failed;
487
488 next_log_block++;
489 wrap(journal, next_log_block);
490
491 /* What kind of buffer is it?
492 *
493 * If it is a descriptor block, check that it has the
494 * expected sequence number. Otherwise, we're all done
495 * here. */
496
497 tmp = (journal_header_t *)bh->b_data;
498
499 if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) {
500 brelse(bh);
501 break;
502 }
503
504 blocktype = be32_to_cpu(tmp->h_blocktype);
505 sequence = be32_to_cpu(tmp->h_sequence);
506 jbd_debug(3, "Found magic %d, sequence %d\n",
507 blocktype, sequence);
508
509 if (sequence != next_commit_ID) {
510 brelse(bh);
511 break;
512 }
513
514 /* OK, we have a valid descriptor block which matches
515 * all of the sequence number checks. What are we going
516 * to do with it? That depends on the pass... */
517
518 switch(blocktype) {
519 case JBD2_DESCRIPTOR_BLOCK:
520 /* Verify checksum first */
521 if (jbd2_journal_has_csum_v2or3(journal))
522 descr_csum_size =
523 sizeof(struct jbd2_journal_block_tail);
524 if (descr_csum_size > 0 &&
525 !jbd2_descr_block_csum_verify(journal,
526 bh->b_data)) {
527 printk(KERN_ERR "JBD2: Invalid checksum "
528 "recovering block %lu in log\n",
529 next_log_block);
530 err = -EFSBADCRC;
531 brelse(bh);
532 goto failed;
533 }
534
535 /* If it is a valid descriptor block, replay it
536 * in pass REPLAY; if journal_checksums enabled, then
537 * calculate checksums in PASS_SCAN, otherwise,
538 * just skip over the blocks it describes. */
539 if (pass != PASS_REPLAY) {
540 if (pass == PASS_SCAN &&
541 jbd2_has_feature_checksum(journal) &&
542 !info->end_transaction) {
543 if (calc_chksums(journal, bh,
544 &next_log_block,
545 &crc32_sum)) {
546 put_bh(bh);
547 break;
548 }
549 put_bh(bh);
550 continue;
551 }
552 next_log_block += count_tags(journal, bh);
553 wrap(journal, next_log_block);
554 put_bh(bh);
555 continue;
556 }
557
558 /* A descriptor block: we can now write all of
559 * the data blocks. Yay, useful work is finally
560 * getting done here! */
561
562 tagp = &bh->b_data[sizeof(journal_header_t)];
563 while ((tagp - bh->b_data + tag_bytes)
564 <= journal->j_blocksize - descr_csum_size) {
565 unsigned long io_block;
566
567 tag = (journal_block_tag_t *) tagp;
568 flags = be16_to_cpu(tag->t_flags);
569
570 io_block = next_log_block++;
571 wrap(journal, next_log_block);
572 err = jread(&obh, journal, io_block);
573 if (err) {
574 /* Recover what we can, but
575 * report failure at the end. */
576 success = err;
577 printk(KERN_ERR
578 "JBD2: IO error %d recovering "
579 "block %ld in log\n",
580 err, io_block);
581 } else {
582 unsigned long long blocknr;
583
584 J_ASSERT(obh != NULL);
585 blocknr = read_tag_block(journal,
586 tag);
587
588 /* If the block has been
589 * revoked, then we're all done
590 * here. */
591 if (jbd2_journal_test_revoke
592 (journal, blocknr,
593 next_commit_ID)) {
594 brelse(obh);
595 ++info->nr_revoke_hits;
596 goto skip_write;
597 }
598
599 /* Look for block corruption */
600 if (!jbd2_block_tag_csum_verify(
601 journal, tag, obh->b_data,
602 be32_to_cpu(tmp->h_sequence))) {
603 brelse(obh);
604 success = -EFSBADCRC;
605 printk(KERN_ERR "JBD2: Invalid "
606 "checksum recovering "
607 "block %llu in log\n",
608 blocknr);
609 block_error = 1;
610 goto skip_write;
611 }
612
613 /* Find a buffer for the new
614 * data being restored */
615 nbh = __getblk(journal->j_fs_dev,
616 blocknr,
617 journal->j_blocksize);
618 if (nbh == NULL) {
619 printk(KERN_ERR
620 "JBD2: Out of memory "
621 "during recovery.\n");
622 err = -ENOMEM;
623 brelse(bh);
624 brelse(obh);
625 goto failed;
626 }
627
628 lock_buffer(nbh);
629 memcpy(nbh->b_data, obh->b_data,
630 journal->j_blocksize);
631 if (flags & JBD2_FLAG_ESCAPE) {
632 *((__be32 *)nbh->b_data) =
633 cpu_to_be32(JBD2_MAGIC_NUMBER);
634 }
635
636 BUFFER_TRACE(nbh, "marking dirty");
637 set_buffer_uptodate(nbh);
638 mark_buffer_dirty(nbh);
639 BUFFER_TRACE(nbh, "marking uptodate");
640 ++info->nr_replays;
641 /* ll_rw_block(WRITE, 1, &nbh); */
642 unlock_buffer(nbh);
643 brelse(obh);
644 brelse(nbh);
645 }
646
647 skip_write:
648 tagp += tag_bytes;
649 if (!(flags & JBD2_FLAG_SAME_UUID))
650 tagp += 16;
651
652 if (flags & JBD2_FLAG_LAST_TAG)
653 break;
654 }
655
656 brelse(bh);
657 continue;
658
659 case JBD2_COMMIT_BLOCK:
660 /* How to differentiate between interrupted commit
661 * and journal corruption ?
662 *
663 * {nth transaction}
664 * Checksum Verification Failed
665 * |
666 * ____________________
667 * | |
668 * async_commit sync_commit
669 * | |
670 * | GO TO NEXT "Journal Corruption"
671 * | TRANSACTION
672 * |
673 * {(n+1)th transanction}
674 * |
675 * _______|______________
676 * | |
677 * Commit block found Commit block not found
678 * | |
679 * "Journal Corruption" |
680 * _____________|_________
681 * | |
682 * nth trans corrupt OR nth trans
683 * and (n+1)th interrupted interrupted
684 * before commit block
685 * could reach the disk.
686 * (Cannot find the difference in above
687 * mentioned conditions. Hence assume
688 * "Interrupted Commit".)
689 */
690
691 /* Found an expected commit block: if checksums
692 * are present verify them in PASS_SCAN; else not
693 * much to do other than move on to the next sequence
694 * number. */
695 if (pass == PASS_SCAN &&
696 jbd2_has_feature_checksum(journal)) {
697 int chksum_err, chksum_seen;
698 struct commit_header *cbh =
699 (struct commit_header *)bh->b_data;
700 unsigned found_chksum =
701 be32_to_cpu(cbh->h_chksum[0]);
702
703 chksum_err = chksum_seen = 0;
704
705 if (info->end_transaction) {
706 journal->j_failed_commit =
707 info->end_transaction;
708 brelse(bh);
709 break;
710 }
711
712 if (crc32_sum == found_chksum &&
713 cbh->h_chksum_type == JBD2_CRC32_CHKSUM &&
714 cbh->h_chksum_size ==
715 JBD2_CRC32_CHKSUM_SIZE)
716 chksum_seen = 1;
717 else if (!(cbh->h_chksum_type == 0 &&
718 cbh->h_chksum_size == 0 &&
719 found_chksum == 0 &&
720 !chksum_seen))
721 /*
722 * If fs is mounted using an old kernel and then
723 * kernel with journal_chksum is used then we
724 * get a situation where the journal flag has
725 * checksum flag set but checksums are not
726 * present i.e chksum = 0, in the individual
727 * commit blocks.
728 * Hence to avoid checksum failures, in this
729 * situation, this extra check is added.
730 */
731 chksum_err = 1;
732
733 if (chksum_err) {
734 info->end_transaction = next_commit_ID;
735
736 if (!jbd2_has_feature_async_commit(journal)) {
737 journal->j_failed_commit =
738 next_commit_ID;
739 brelse(bh);
740 break;
741 }
742 }
743 crc32_sum = ~0;
744 }
745 if (pass == PASS_SCAN &&
746 !jbd2_commit_block_csum_verify(journal,
747 bh->b_data)) {
748 info->end_transaction = next_commit_ID;
749
750 if (!jbd2_has_feature_async_commit(journal)) {
751 journal->j_failed_commit =
752 next_commit_ID;
753 brelse(bh);
754 break;
755 }
756 }
757 brelse(bh);
758 next_commit_ID++;
759 continue;
760
761 case JBD2_REVOKE_BLOCK:
762 /* If we aren't in the REVOKE pass, then we can
763 * just skip over this block. */
764 if (pass != PASS_REVOKE) {
765 brelse(bh);
766 continue;
767 }
768
769 err = scan_revoke_records(journal, bh,
770 next_commit_ID, info);
771 brelse(bh);
772 if (err)
773 goto failed;
774 continue;
775
776 default:
777 jbd_debug(3, "Unrecognised magic %d, end of scan.\n",
778 blocktype);
779 brelse(bh);
780 goto done;
781 }
782 }
783
784 done:
785 /*
786 * We broke out of the log scan loop: either we came to the
787 * known end of the log or we found an unexpected block in the
788 * log. If the latter happened, then we know that the "current"
789 * transaction marks the end of the valid log.
790 */
791
792 if (pass == PASS_SCAN) {
793 if (!info->end_transaction)
794 info->end_transaction = next_commit_ID;
795 } else {
796 /* It's really bad news if different passes end up at
797 * different places (but possible due to IO errors). */
798 if (info->end_transaction != next_commit_ID) {
799 printk(KERN_ERR "JBD2: recovery pass %d ended at "
800 "transaction %u, expected %u\n",
801 pass, next_commit_ID, info->end_transaction);
802 if (!success)
803 success = -EIO;
804 }
805 }
806 if (block_error && success == 0)
807 success = -EIO;
808 return success;
809
810 failed:
811 return err;
812 }
813
814 static int jbd2_revoke_block_csum_verify(journal_t *j,
815 void *buf)
816 {
817 struct jbd2_journal_revoke_tail *tail;
818 __be32 provided;
819 __u32 calculated;
820
821 if (!jbd2_journal_has_csum_v2or3(j))
822 return 1;
823
824 tail = (struct jbd2_journal_revoke_tail *)(buf + j->j_blocksize -
825 sizeof(struct jbd2_journal_revoke_tail));
826 provided = tail->r_checksum;
827 tail->r_checksum = 0;
828 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
829 tail->r_checksum = provided;
830
831 return provided == cpu_to_be32(calculated);
832 }
833
834 /* Scan a revoke record, marking all blocks mentioned as revoked. */
835
836 static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
837 tid_t sequence, struct recovery_info *info)
838 {
839 jbd2_journal_revoke_header_t *header;
840 int offset, max;
841 int csum_size = 0;
842 __u32 rcount;
843 int record_len = 4;
844
845 header = (jbd2_journal_revoke_header_t *) bh->b_data;
846 offset = sizeof(jbd2_journal_revoke_header_t);
847 rcount = be32_to_cpu(header->r_count);
848
849 if (!jbd2_revoke_block_csum_verify(journal, header))
850 return -EFSBADCRC;
851
852 if (jbd2_journal_has_csum_v2or3(journal))
853 csum_size = sizeof(struct jbd2_journal_revoke_tail);
854 if (rcount > journal->j_blocksize - csum_size)
855 return -EINVAL;
856 max = rcount;
857
858 if (jbd2_has_feature_64bit(journal))
859 record_len = 8;
860
861 while (offset + record_len <= max) {
862 unsigned long long blocknr;
863 int err;
864
865 if (record_len == 4)
866 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
867 else
868 blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset)));
869 offset += record_len;
870 err = jbd2_journal_set_revoke(journal, blocknr, sequence);
871 if (err)
872 return err;
873 ++info->nr_revokes;
874 }
875 return 0;
876 }
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