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