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 unsigned long head_block;
33
34 int nr_replays;
35 int nr_revokes;
36 int nr_revoke_hits;
37 };
38
39 static int do_one_pass(journal_t *journal,
40 struct recovery_info *info, enum passtype pass);
41 static int scan_revoke_records(journal_t *, struct buffer_head *,
42 tid_t, struct recovery_info *);
43
44 #ifdef __KERNEL__
45
46 /* Release readahead buffers after use */
journal_brelse_array(struct buffer_head * b[],int n)47 static void journal_brelse_array(struct buffer_head *b[], int n)
48 {
49 while (--n >= 0)
50 brelse (b[n]);
51 }
52
53
54 /*
55 * When reading from the journal, we are going through the block device
56 * layer directly and so there is no readahead being done for us. We
57 * need to implement any readahead ourselves if we want it to happen at
58 * all. Recovery is basically one long sequential read, so make sure we
59 * do the IO in reasonably large chunks.
60 *
61 * This is not so critical that we need to be enormously clever about
62 * the readahead size, though. 128K is a purely arbitrary, good-enough
63 * fixed value.
64 */
65
66 #define MAXBUF 8
do_readahead(journal_t * journal,unsigned int start)67 static int do_readahead(journal_t *journal, unsigned int start)
68 {
69 int err;
70 unsigned int max, nbufs, next;
71 unsigned long long blocknr;
72 struct buffer_head *bh;
73
74 struct buffer_head * bufs[MAXBUF];
75
76 /* Do up to 128K of readahead */
77 max = start + (128 * 1024 / journal->j_blocksize);
78 if (max > journal->j_total_len)
79 max = journal->j_total_len;
80
81 /* Do the readahead itself. We'll submit MAXBUF buffer_heads at
82 * a time to the block device IO layer. */
83
84 nbufs = 0;
85
86 for (next = start; next < max; next++) {
87 err = jbd2_journal_bmap(journal, next, &blocknr);
88
89 if (err) {
90 printk(KERN_ERR "JBD2: bad block at offset %u\n",
91 next);
92 goto failed;
93 }
94
95 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
96 if (!bh) {
97 err = -ENOMEM;
98 goto failed;
99 }
100
101 if (!buffer_uptodate(bh) && !buffer_locked(bh)) {
102 bufs[nbufs++] = bh;
103 if (nbufs == MAXBUF) {
104 bh_readahead_batch(nbufs, bufs, 0);
105 journal_brelse_array(bufs, nbufs);
106 nbufs = 0;
107 }
108 } else
109 brelse(bh);
110 }
111
112 if (nbufs)
113 bh_readahead_batch(nbufs, bufs, 0);
114 err = 0;
115
116 failed:
117 if (nbufs)
118 journal_brelse_array(bufs, nbufs);
119 return err;
120 }
121
122 #endif /* __KERNEL__ */
123
124
125 /*
126 * Read a block from the journal
127 */
128
jread(struct buffer_head ** bhp,journal_t * journal,unsigned int offset)129 static int jread(struct buffer_head **bhp, journal_t *journal,
130 unsigned int offset)
131 {
132 int err;
133 unsigned long long blocknr;
134 struct buffer_head *bh;
135
136 *bhp = NULL;
137
138 if (offset >= journal->j_total_len) {
139 printk(KERN_ERR "JBD2: corrupted journal superblock\n");
140 return -EFSCORRUPTED;
141 }
142
143 err = jbd2_journal_bmap(journal, offset, &blocknr);
144
145 if (err) {
146 printk(KERN_ERR "JBD2: bad block at offset %u\n",
147 offset);
148 return err;
149 }
150
151 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
152 if (!bh)
153 return -ENOMEM;
154
155 if (!buffer_uptodate(bh)) {
156 /*
157 * If this is a brand new buffer, start readahead.
158 * Otherwise, we assume we are already reading it.
159 */
160 bool need_readahead = !buffer_req(bh);
161
162 bh_read_nowait(bh, 0);
163 if (need_readahead)
164 do_readahead(journal, offset);
165 wait_on_buffer(bh);
166 }
167
168 if (!buffer_uptodate(bh)) {
169 printk(KERN_ERR "JBD2: Failed to read block at offset %u\n",
170 offset);
171 brelse(bh);
172 return -EIO;
173 }
174
175 *bhp = bh;
176 return 0;
177 }
178
jbd2_descriptor_block_csum_verify(journal_t * j,void * buf)179 static int jbd2_descriptor_block_csum_verify(journal_t *j, void *buf)
180 {
181 struct jbd2_journal_block_tail *tail;
182 __be32 provided;
183 __u32 calculated;
184
185 if (!jbd2_journal_has_csum_v2or3(j))
186 return 1;
187
188 tail = (struct jbd2_journal_block_tail *)((char *)buf +
189 j->j_blocksize - sizeof(struct jbd2_journal_block_tail));
190 provided = tail->t_checksum;
191 tail->t_checksum = 0;
192 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
193 tail->t_checksum = provided;
194
195 return provided == cpu_to_be32(calculated);
196 }
197
198 /*
199 * Count the number of in-use tags in a journal descriptor block.
200 */
201
count_tags(journal_t * journal,struct buffer_head * bh)202 static int count_tags(journal_t *journal, struct buffer_head *bh)
203 {
204 char * tagp;
205 journal_block_tag_t tag;
206 int nr = 0, size = journal->j_blocksize;
207 int tag_bytes = journal_tag_bytes(journal);
208
209 if (jbd2_journal_has_csum_v2or3(journal))
210 size -= sizeof(struct jbd2_journal_block_tail);
211
212 tagp = &bh->b_data[sizeof(journal_header_t)];
213
214 while ((tagp - bh->b_data + tag_bytes) <= size) {
215 memcpy(&tag, tagp, sizeof(tag));
216
217 nr++;
218 tagp += tag_bytes;
219 if (!(tag.t_flags & cpu_to_be16(JBD2_FLAG_SAME_UUID)))
220 tagp += 16;
221
222 if (tag.t_flags & cpu_to_be16(JBD2_FLAG_LAST_TAG))
223 break;
224 }
225
226 return nr;
227 }
228
229
230 /* Make sure we wrap around the log correctly! */
231 #define wrap(journal, var) \
232 do { \
233 if (var >= (journal)->j_last) \
234 var -= ((journal)->j_last - (journal)->j_first); \
235 } while (0)
236
fc_do_one_pass(journal_t * journal,struct recovery_info * info,enum passtype pass)237 static int fc_do_one_pass(journal_t *journal,
238 struct recovery_info *info, enum passtype pass)
239 {
240 unsigned int expected_commit_id = info->end_transaction;
241 unsigned long next_fc_block;
242 struct buffer_head *bh;
243 int err = 0;
244
245 next_fc_block = journal->j_fc_first;
246 if (!journal->j_fc_replay_callback)
247 return 0;
248
249 while (next_fc_block <= journal->j_fc_last) {
250 jbd2_debug(3, "Fast commit replay: next block %ld\n",
251 next_fc_block);
252 err = jread(&bh, journal, next_fc_block);
253 if (err) {
254 jbd2_debug(3, "Fast commit replay: read error\n");
255 break;
256 }
257
258 err = journal->j_fc_replay_callback(journal, bh, pass,
259 next_fc_block - journal->j_fc_first,
260 expected_commit_id);
261 brelse(bh);
262 next_fc_block++;
263 if (err < 0 || err == JBD2_FC_REPLAY_STOP)
264 break;
265 err = 0;
266 }
267
268 if (err)
269 jbd2_debug(3, "Fast commit replay failed, err = %d\n", err);
270
271 return err;
272 }
273
274 /**
275 * jbd2_journal_recover - recovers a on-disk journal
276 * @journal: the journal to recover
277 *
278 * The primary function for recovering the log contents when mounting a
279 * journaled device.
280 *
281 * Recovery is done in three passes. In the first pass, we look for the
282 * end of the log. In the second, we assemble the list of revoke
283 * blocks. In the third and final pass, we replay any un-revoked blocks
284 * in the log.
285 */
jbd2_journal_recover(journal_t * journal)286 int jbd2_journal_recover(journal_t *journal)
287 {
288 int err, err2;
289 journal_superblock_t * sb;
290
291 struct recovery_info info;
292 errseq_t wb_err;
293 struct address_space *mapping;
294
295 memset(&info, 0, sizeof(info));
296 sb = journal->j_superblock;
297
298 /*
299 * The journal superblock's s_start field (the current log head)
300 * is always zero if, and only if, the journal was cleanly
301 * unmounted.
302 */
303 if (!sb->s_start) {
304 jbd2_debug(1, "No recovery required, last transaction %d, head block %u\n",
305 be32_to_cpu(sb->s_sequence), be32_to_cpu(sb->s_head));
306 journal->j_transaction_sequence = be32_to_cpu(sb->s_sequence) + 1;
307 journal->j_head = be32_to_cpu(sb->s_head);
308 return 0;
309 }
310
311 wb_err = 0;
312 mapping = journal->j_fs_dev->bd_inode->i_mapping;
313 errseq_check_and_advance(&mapping->wb_err, &wb_err);
314 err = do_one_pass(journal, &info, PASS_SCAN);
315 if (!err)
316 err = do_one_pass(journal, &info, PASS_REVOKE);
317 if (!err)
318 err = do_one_pass(journal, &info, PASS_REPLAY);
319
320 jbd2_debug(1, "JBD2: recovery, exit status %d, "
321 "recovered transactions %u to %u\n",
322 err, info.start_transaction, info.end_transaction);
323 jbd2_debug(1, "JBD2: Replayed %d and revoked %d/%d blocks\n",
324 info.nr_replays, info.nr_revoke_hits, info.nr_revokes);
325
326 /* Restart the log at the next transaction ID, thus invalidating
327 * any existing commit records in the log. */
328 journal->j_transaction_sequence = ++info.end_transaction;
329 journal->j_head = info.head_block;
330 jbd2_debug(1, "JBD2: last transaction %d, head block %lu\n",
331 journal->j_transaction_sequence, journal->j_head);
332
333 jbd2_journal_clear_revoke(journal);
334 err2 = sync_blockdev(journal->j_fs_dev);
335 if (!err)
336 err = err2;
337 err2 = errseq_check_and_advance(&mapping->wb_err, &wb_err);
338 if (!err)
339 err = err2;
340 /* Make sure all replayed data is on permanent storage */
341 if (journal->j_flags & JBD2_BARRIER) {
342 err2 = blkdev_issue_flush(journal->j_fs_dev);
343 if (!err)
344 err = err2;
345 }
346 return err;
347 }
348
349 /**
350 * jbd2_journal_skip_recovery - Start journal and wipe exiting records
351 * @journal: journal to startup
352 *
353 * Locate any valid recovery information from the journal and set up the
354 * journal structures in memory to ignore it (presumably because the
355 * caller has evidence that it is out of date).
356 * This function doesn't appear to be exported..
357 *
358 * We perform one pass over the journal to allow us to tell the user how
359 * much recovery information is being erased, and to let us initialise
360 * the journal transaction sequence numbers to the next unused ID.
361 */
jbd2_journal_skip_recovery(journal_t * journal)362 int jbd2_journal_skip_recovery(journal_t *journal)
363 {
364 int err;
365
366 struct recovery_info info;
367
368 memset (&info, 0, sizeof(info));
369
370 err = do_one_pass(journal, &info, PASS_SCAN);
371
372 if (err) {
373 printk(KERN_ERR "JBD2: error %d scanning journal\n", err);
374 ++journal->j_transaction_sequence;
375 journal->j_head = journal->j_first;
376 } else {
377 #ifdef CONFIG_JBD2_DEBUG
378 int dropped = info.end_transaction -
379 be32_to_cpu(journal->j_superblock->s_sequence);
380 jbd2_debug(1,
381 "JBD2: ignoring %d transaction%s from the journal.\n",
382 dropped, (dropped == 1) ? "" : "s");
383 #endif
384 journal->j_transaction_sequence = ++info.end_transaction;
385 journal->j_head = info.head_block;
386 }
387
388 journal->j_tail = 0;
389 return err;
390 }
391
read_tag_block(journal_t * journal,journal_block_tag_t * tag)392 static inline unsigned long long read_tag_block(journal_t *journal,
393 journal_block_tag_t *tag)
394 {
395 unsigned long long block = be32_to_cpu(tag->t_blocknr);
396 if (jbd2_has_feature_64bit(journal))
397 block |= (u64)be32_to_cpu(tag->t_blocknr_high) << 32;
398 return block;
399 }
400
401 /*
402 * calc_chksums calculates the checksums for the blocks described in the
403 * descriptor block.
404 */
calc_chksums(journal_t * journal,struct buffer_head * bh,unsigned long * next_log_block,__u32 * crc32_sum)405 static int calc_chksums(journal_t *journal, struct buffer_head *bh,
406 unsigned long *next_log_block, __u32 *crc32_sum)
407 {
408 int i, num_blks, err;
409 unsigned long io_block;
410 struct buffer_head *obh;
411
412 num_blks = count_tags(journal, bh);
413 /* Calculate checksum of the descriptor block. */
414 *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size);
415
416 for (i = 0; i < num_blks; i++) {
417 io_block = (*next_log_block)++;
418 wrap(journal, *next_log_block);
419 err = jread(&obh, journal, io_block);
420 if (err) {
421 printk(KERN_ERR "JBD2: IO error %d recovering block "
422 "%lu in log\n", err, io_block);
423 return 1;
424 } else {
425 *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data,
426 obh->b_size);
427 }
428 put_bh(obh);
429 }
430 return 0;
431 }
432
jbd2_commit_block_csum_verify(journal_t * j,void * buf)433 static int jbd2_commit_block_csum_verify(journal_t *j, void *buf)
434 {
435 struct commit_header *h;
436 __be32 provided;
437 __u32 calculated;
438
439 if (!jbd2_journal_has_csum_v2or3(j))
440 return 1;
441
442 h = buf;
443 provided = h->h_chksum[0];
444 h->h_chksum[0] = 0;
445 calculated = jbd2_chksum(j, j->j_csum_seed, buf, j->j_blocksize);
446 h->h_chksum[0] = provided;
447
448 return provided == cpu_to_be32(calculated);
449 }
450
jbd2_block_tag_csum_verify(journal_t * j,journal_block_tag_t * tag,journal_block_tag3_t * tag3,void * buf,__u32 sequence)451 static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag,
452 journal_block_tag3_t *tag3,
453 void *buf, __u32 sequence)
454 {
455 __u32 csum32;
456 __be32 seq;
457
458 if (!jbd2_journal_has_csum_v2or3(j))
459 return 1;
460
461 seq = cpu_to_be32(sequence);
462 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
463 csum32 = jbd2_chksum(j, csum32, buf, j->j_blocksize);
464
465 if (jbd2_has_feature_csum3(j))
466 return tag3->t_checksum == cpu_to_be32(csum32);
467 else
468 return tag->t_checksum == cpu_to_be16(csum32);
469 }
470
do_one_pass(journal_t * journal,struct recovery_info * info,enum passtype pass)471 static int do_one_pass(journal_t *journal,
472 struct recovery_info *info, enum passtype pass)
473 {
474 unsigned int first_commit_ID, next_commit_ID;
475 unsigned long next_log_block, head_block;
476 int err, success = 0;
477 journal_superblock_t * sb;
478 journal_header_t * tmp;
479 struct buffer_head * bh;
480 unsigned int sequence;
481 int blocktype;
482 int tag_bytes = journal_tag_bytes(journal);
483 __u32 crc32_sum = ~0; /* Transactional Checksums */
484 int descr_csum_size = 0;
485 int block_error = 0;
486 bool need_check_commit_time = false;
487 __u64 last_trans_commit_time = 0, commit_time;
488
489 /*
490 * First thing is to establish what we expect to find in the log
491 * (in terms of transaction IDs), and where (in terms of log
492 * block offsets): query the superblock.
493 */
494
495 sb = journal->j_superblock;
496 next_commit_ID = be32_to_cpu(sb->s_sequence);
497 next_log_block = be32_to_cpu(sb->s_start);
498 head_block = next_log_block;
499
500 first_commit_ID = next_commit_ID;
501 if (pass == PASS_SCAN)
502 info->start_transaction = first_commit_ID;
503
504 jbd2_debug(1, "Starting recovery pass %d\n", pass);
505
506 /*
507 * Now we walk through the log, transaction by transaction,
508 * making sure that each transaction has a commit block in the
509 * expected place. Each complete transaction gets replayed back
510 * into the main filesystem.
511 */
512
513 while (1) {
514 int flags;
515 char * tagp;
516 journal_block_tag_t tag;
517 struct buffer_head * obh;
518 struct buffer_head * nbh;
519
520 cond_resched();
521
522 /* If we already know where to stop the log traversal,
523 * check right now that we haven't gone past the end of
524 * the log. */
525
526 if (pass != PASS_SCAN)
527 if (tid_geq(next_commit_ID, info->end_transaction))
528 break;
529
530 jbd2_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
531 next_commit_ID, next_log_block, journal->j_last);
532
533 /* Skip over each chunk of the transaction looking
534 * either the next descriptor block or the final commit
535 * record. */
536
537 jbd2_debug(3, "JBD2: checking block %ld\n", next_log_block);
538 err = jread(&bh, journal, next_log_block);
539 if (err)
540 goto failed;
541
542 next_log_block++;
543 wrap(journal, next_log_block);
544
545 /* What kind of buffer is it?
546 *
547 * If it is a descriptor block, check that it has the
548 * expected sequence number. Otherwise, we're all done
549 * here. */
550
551 tmp = (journal_header_t *)bh->b_data;
552
553 if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) {
554 brelse(bh);
555 break;
556 }
557
558 blocktype = be32_to_cpu(tmp->h_blocktype);
559 sequence = be32_to_cpu(tmp->h_sequence);
560 jbd2_debug(3, "Found magic %d, sequence %d\n",
561 blocktype, sequence);
562
563 if (sequence != next_commit_ID) {
564 brelse(bh);
565 break;
566 }
567
568 /* OK, we have a valid descriptor block which matches
569 * all of the sequence number checks. What are we going
570 * to do with it? That depends on the pass... */
571
572 switch(blocktype) {
573 case JBD2_DESCRIPTOR_BLOCK:
574 /* Verify checksum first */
575 if (jbd2_journal_has_csum_v2or3(journal))
576 descr_csum_size =
577 sizeof(struct jbd2_journal_block_tail);
578 if (descr_csum_size > 0 &&
579 !jbd2_descriptor_block_csum_verify(journal,
580 bh->b_data)) {
581 /*
582 * PASS_SCAN can see stale blocks due to lazy
583 * journal init. Don't error out on those yet.
584 */
585 if (pass != PASS_SCAN) {
586 pr_err("JBD2: Invalid checksum recovering block %lu in log\n",
587 next_log_block);
588 err = -EFSBADCRC;
589 brelse(bh);
590 goto failed;
591 }
592 need_check_commit_time = true;
593 jbd2_debug(1,
594 "invalid descriptor block found in %lu\n",
595 next_log_block);
596 }
597
598 /* If it is a valid descriptor block, replay it
599 * in pass REPLAY; if journal_checksums enabled, then
600 * calculate checksums in PASS_SCAN, otherwise,
601 * just skip over the blocks it describes. */
602 if (pass != PASS_REPLAY) {
603 if (pass == PASS_SCAN &&
604 jbd2_has_feature_checksum(journal) &&
605 !need_check_commit_time &&
606 !info->end_transaction) {
607 if (calc_chksums(journal, bh,
608 &next_log_block,
609 &crc32_sum)) {
610 put_bh(bh);
611 break;
612 }
613 put_bh(bh);
614 continue;
615 }
616 next_log_block += count_tags(journal, bh);
617 wrap(journal, next_log_block);
618 put_bh(bh);
619 continue;
620 }
621
622 /* A descriptor block: we can now write all of
623 * the data blocks. Yay, useful work is finally
624 * getting done here! */
625
626 tagp = &bh->b_data[sizeof(journal_header_t)];
627 while ((tagp - bh->b_data + tag_bytes)
628 <= journal->j_blocksize - descr_csum_size) {
629 unsigned long io_block;
630
631 memcpy(&tag, tagp, sizeof(tag));
632 flags = be16_to_cpu(tag.t_flags);
633
634 io_block = next_log_block++;
635 wrap(journal, next_log_block);
636 err = jread(&obh, journal, io_block);
637 if (err) {
638 /* Recover what we can, but
639 * report failure at the end. */
640 success = err;
641 printk(KERN_ERR
642 "JBD2: IO error %d recovering "
643 "block %ld in log\n",
644 err, io_block);
645 } else {
646 unsigned long long blocknr;
647
648 J_ASSERT(obh != NULL);
649 blocknr = read_tag_block(journal,
650 &tag);
651
652 /* If the block has been
653 * revoked, then we're all done
654 * here. */
655 if (jbd2_journal_test_revoke
656 (journal, blocknr,
657 next_commit_ID)) {
658 brelse(obh);
659 ++info->nr_revoke_hits;
660 goto skip_write;
661 }
662
663 /* Look for block corruption */
664 if (!jbd2_block_tag_csum_verify(
665 journal, &tag, (journal_block_tag3_t *)tagp,
666 obh->b_data, be32_to_cpu(tmp->h_sequence))) {
667 brelse(obh);
668 success = -EFSBADCRC;
669 printk(KERN_ERR "JBD2: Invalid "
670 "checksum recovering "
671 "data block %llu in "
672 "log\n", blocknr);
673 block_error = 1;
674 goto skip_write;
675 }
676
677 /* Find a buffer for the new
678 * data being restored */
679 nbh = __getblk(journal->j_fs_dev,
680 blocknr,
681 journal->j_blocksize);
682 if (nbh == NULL) {
683 printk(KERN_ERR
684 "JBD2: Out of memory "
685 "during recovery.\n");
686 err = -ENOMEM;
687 brelse(bh);
688 brelse(obh);
689 goto failed;
690 }
691
692 lock_buffer(nbh);
693 memcpy(nbh->b_data, obh->b_data,
694 journal->j_blocksize);
695 if (flags & JBD2_FLAG_ESCAPE) {
696 *((__be32 *)nbh->b_data) =
697 cpu_to_be32(JBD2_MAGIC_NUMBER);
698 }
699
700 BUFFER_TRACE(nbh, "marking dirty");
701 set_buffer_uptodate(nbh);
702 mark_buffer_dirty(nbh);
703 BUFFER_TRACE(nbh, "marking uptodate");
704 ++info->nr_replays;
705 unlock_buffer(nbh);
706 brelse(obh);
707 brelse(nbh);
708 }
709
710 skip_write:
711 tagp += tag_bytes;
712 if (!(flags & JBD2_FLAG_SAME_UUID))
713 tagp += 16;
714
715 if (flags & JBD2_FLAG_LAST_TAG)
716 break;
717 }
718
719 brelse(bh);
720 continue;
721
722 case JBD2_COMMIT_BLOCK:
723 /* How to differentiate between interrupted commit
724 * and journal corruption ?
725 *
726 * {nth transaction}
727 * Checksum Verification Failed
728 * |
729 * ____________________
730 * | |
731 * async_commit sync_commit
732 * | |
733 * | GO TO NEXT "Journal Corruption"
734 * | TRANSACTION
735 * |
736 * {(n+1)th transanction}
737 * |
738 * _______|______________
739 * | |
740 * Commit block found Commit block not found
741 * | |
742 * "Journal Corruption" |
743 * _____________|_________
744 * | |
745 * nth trans corrupt OR nth trans
746 * and (n+1)th interrupted interrupted
747 * before commit block
748 * could reach the disk.
749 * (Cannot find the difference in above
750 * mentioned conditions. Hence assume
751 * "Interrupted Commit".)
752 */
753 commit_time = be64_to_cpu(
754 ((struct commit_header *)bh->b_data)->h_commit_sec);
755 /*
756 * If need_check_commit_time is set, it means we are in
757 * PASS_SCAN and csum verify failed before. If
758 * commit_time is increasing, it's the same journal,
759 * otherwise it is stale journal block, just end this
760 * recovery.
761 */
762 if (need_check_commit_time) {
763 if (commit_time >= last_trans_commit_time) {
764 pr_err("JBD2: Invalid checksum found in transaction %u\n",
765 next_commit_ID);
766 err = -EFSBADCRC;
767 brelse(bh);
768 goto failed;
769 }
770 ignore_crc_mismatch:
771 /*
772 * It likely does not belong to same journal,
773 * just end this recovery with success.
774 */
775 jbd2_debug(1, "JBD2: Invalid checksum ignored in transaction %u, likely stale data\n",
776 next_commit_ID);
777 brelse(bh);
778 goto done;
779 }
780
781 /*
782 * Found an expected commit block: if checksums
783 * are present, verify them in PASS_SCAN; else not
784 * much to do other than move on to the next sequence
785 * number.
786 */
787 if (pass == PASS_SCAN &&
788 jbd2_has_feature_checksum(journal)) {
789 struct commit_header *cbh =
790 (struct commit_header *)bh->b_data;
791 unsigned found_chksum =
792 be32_to_cpu(cbh->h_chksum[0]);
793
794 if (info->end_transaction) {
795 journal->j_failed_commit =
796 info->end_transaction;
797 brelse(bh);
798 break;
799 }
800
801 /* Neither checksum match nor unused? */
802 if (!((crc32_sum == found_chksum &&
803 cbh->h_chksum_type ==
804 JBD2_CRC32_CHKSUM &&
805 cbh->h_chksum_size ==
806 JBD2_CRC32_CHKSUM_SIZE) ||
807 (cbh->h_chksum_type == 0 &&
808 cbh->h_chksum_size == 0 &&
809 found_chksum == 0)))
810 goto chksum_error;
811
812 crc32_sum = ~0;
813 }
814 if (pass == PASS_SCAN &&
815 !jbd2_commit_block_csum_verify(journal,
816 bh->b_data)) {
817 chksum_error:
818 if (commit_time < last_trans_commit_time)
819 goto ignore_crc_mismatch;
820 info->end_transaction = next_commit_ID;
821 info->head_block = head_block;
822
823 if (!jbd2_has_feature_async_commit(journal)) {
824 journal->j_failed_commit =
825 next_commit_ID;
826 brelse(bh);
827 break;
828 }
829 }
830 if (pass == PASS_SCAN) {
831 last_trans_commit_time = commit_time;
832 head_block = next_log_block;
833 }
834 brelse(bh);
835 next_commit_ID++;
836 continue;
837
838 case JBD2_REVOKE_BLOCK:
839 /*
840 * Check revoke block crc in pass_scan, if csum verify
841 * failed, check commit block time later.
842 */
843 if (pass == PASS_SCAN &&
844 !jbd2_descriptor_block_csum_verify(journal,
845 bh->b_data)) {
846 jbd2_debug(1, "JBD2: invalid revoke block found in %lu\n",
847 next_log_block);
848 need_check_commit_time = true;
849 }
850 /* If we aren't in the REVOKE pass, then we can
851 * just skip over this block. */
852 if (pass != PASS_REVOKE) {
853 brelse(bh);
854 continue;
855 }
856
857 err = scan_revoke_records(journal, bh,
858 next_commit_ID, info);
859 brelse(bh);
860 if (err)
861 goto failed;
862 continue;
863
864 default:
865 jbd2_debug(3, "Unrecognised magic %d, end of scan.\n",
866 blocktype);
867 brelse(bh);
868 goto done;
869 }
870 }
871
872 done:
873 /*
874 * We broke out of the log scan loop: either we came to the
875 * known end of the log or we found an unexpected block in the
876 * log. If the latter happened, then we know that the "current"
877 * transaction marks the end of the valid log.
878 */
879
880 if (pass == PASS_SCAN) {
881 if (!info->end_transaction)
882 info->end_transaction = next_commit_ID;
883 if (!info->head_block)
884 info->head_block = head_block;
885 } else {
886 /* It's really bad news if different passes end up at
887 * different places (but possible due to IO errors). */
888 if (info->end_transaction != next_commit_ID) {
889 printk(KERN_ERR "JBD2: recovery pass %d ended at "
890 "transaction %u, expected %u\n",
891 pass, next_commit_ID, info->end_transaction);
892 if (!success)
893 success = -EIO;
894 }
895 }
896
897 if (jbd2_has_feature_fast_commit(journal) && pass != PASS_REVOKE) {
898 err = fc_do_one_pass(journal, info, pass);
899 if (err)
900 success = err;
901 }
902
903 if (block_error && success == 0)
904 success = -EIO;
905 return success;
906
907 failed:
908 return err;
909 }
910
911 /* Scan a revoke record, marking all blocks mentioned as revoked. */
912
scan_revoke_records(journal_t * journal,struct buffer_head * bh,tid_t sequence,struct recovery_info * info)913 static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
914 tid_t sequence, struct recovery_info *info)
915 {
916 jbd2_journal_revoke_header_t *header;
917 int offset, max;
918 unsigned csum_size = 0;
919 __u32 rcount;
920 int record_len = 4;
921
922 header = (jbd2_journal_revoke_header_t *) bh->b_data;
923 offset = sizeof(jbd2_journal_revoke_header_t);
924 rcount = be32_to_cpu(header->r_count);
925
926 if (jbd2_journal_has_csum_v2or3(journal))
927 csum_size = sizeof(struct jbd2_journal_block_tail);
928 if (rcount > journal->j_blocksize - csum_size)
929 return -EINVAL;
930 max = rcount;
931
932 if (jbd2_has_feature_64bit(journal))
933 record_len = 8;
934
935 while (offset + record_len <= max) {
936 unsigned long long blocknr;
937 int err;
938
939 if (record_len == 4)
940 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
941 else
942 blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset)));
943 offset += record_len;
944 err = jbd2_journal_set_revoke(journal, blocknr, sequence);
945 if (err)
946 return err;
947 ++info->nr_revokes;
948 }
949 return 0;
950 }
951