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_commit_block_csum_verify_partial(journal_t * j,void * buf)451 static bool jbd2_commit_block_csum_verify_partial(journal_t *j, void *buf)
452 {
453 struct commit_header *h;
454 __be32 provided;
455 __u32 calculated;
456 void *tmpbuf;
457
458 tmpbuf = kzalloc(j->j_blocksize, GFP_KERNEL);
459 if (!tmpbuf)
460 return false;
461
462 memcpy(tmpbuf, buf, sizeof(struct commit_header));
463 h = tmpbuf;
464 provided = h->h_chksum[0];
465 h->h_chksum[0] = 0;
466 calculated = jbd2_chksum(j, j->j_csum_seed, tmpbuf, j->j_blocksize);
467 kfree(tmpbuf);
468
469 return provided == cpu_to_be32(calculated);
470 }
471
jbd2_block_tag_csum_verify(journal_t * j,journal_block_tag_t * tag,journal_block_tag3_t * tag3,void * buf,__u32 sequence)472 static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag,
473 journal_block_tag3_t *tag3,
474 void *buf, __u32 sequence)
475 {
476 __u32 csum32;
477 __be32 seq;
478
479 if (!jbd2_journal_has_csum_v2or3(j))
480 return 1;
481
482 seq = cpu_to_be32(sequence);
483 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
484 csum32 = jbd2_chksum(j, csum32, buf, j->j_blocksize);
485
486 if (jbd2_has_feature_csum3(j))
487 return tag3->t_checksum == cpu_to_be32(csum32);
488 else
489 return tag->t_checksum == cpu_to_be16(csum32);
490 }
491
do_one_pass(journal_t * journal,struct recovery_info * info,enum passtype pass)492 static int do_one_pass(journal_t *journal,
493 struct recovery_info *info, enum passtype pass)
494 {
495 unsigned int first_commit_ID, next_commit_ID;
496 unsigned long next_log_block, head_block;
497 int err, success = 0;
498 journal_superblock_t * sb;
499 journal_header_t * tmp;
500 struct buffer_head * bh;
501 unsigned int sequence;
502 int blocktype;
503 int tag_bytes = journal_tag_bytes(journal);
504 __u32 crc32_sum = ~0; /* Transactional Checksums */
505 int descr_csum_size = 0;
506 int block_error = 0;
507 bool need_check_commit_time = false;
508 __u64 last_trans_commit_time = 0, commit_time;
509
510 /*
511 * First thing is to establish what we expect to find in the log
512 * (in terms of transaction IDs), and where (in terms of log
513 * block offsets): query the superblock.
514 */
515
516 sb = journal->j_superblock;
517 next_commit_ID = be32_to_cpu(sb->s_sequence);
518 next_log_block = be32_to_cpu(sb->s_start);
519 head_block = next_log_block;
520
521 first_commit_ID = next_commit_ID;
522 if (pass == PASS_SCAN)
523 info->start_transaction = first_commit_ID;
524
525 jbd2_debug(1, "Starting recovery pass %d\n", pass);
526
527 /*
528 * Now we walk through the log, transaction by transaction,
529 * making sure that each transaction has a commit block in the
530 * expected place. Each complete transaction gets replayed back
531 * into the main filesystem.
532 */
533
534 while (1) {
535 int flags;
536 char * tagp;
537 journal_block_tag_t tag;
538 struct buffer_head * obh;
539 struct buffer_head * nbh;
540
541 cond_resched();
542
543 /* If we already know where to stop the log traversal,
544 * check right now that we haven't gone past the end of
545 * the log. */
546
547 if (pass != PASS_SCAN)
548 if (tid_geq(next_commit_ID, info->end_transaction))
549 break;
550
551 jbd2_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
552 next_commit_ID, next_log_block, journal->j_last);
553
554 /* Skip over each chunk of the transaction looking
555 * either the next descriptor block or the final commit
556 * record. */
557
558 jbd2_debug(3, "JBD2: checking block %ld\n", next_log_block);
559 err = jread(&bh, journal, next_log_block);
560 if (err)
561 goto failed;
562
563 next_log_block++;
564 wrap(journal, next_log_block);
565
566 /* What kind of buffer is it?
567 *
568 * If it is a descriptor block, check that it has the
569 * expected sequence number. Otherwise, we're all done
570 * here. */
571
572 tmp = (journal_header_t *)bh->b_data;
573
574 if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) {
575 brelse(bh);
576 break;
577 }
578
579 blocktype = be32_to_cpu(tmp->h_blocktype);
580 sequence = be32_to_cpu(tmp->h_sequence);
581 jbd2_debug(3, "Found magic %d, sequence %d\n",
582 blocktype, sequence);
583
584 if (sequence != next_commit_ID) {
585 brelse(bh);
586 break;
587 }
588
589 /* OK, we have a valid descriptor block which matches
590 * all of the sequence number checks. What are we going
591 * to do with it? That depends on the pass... */
592
593 switch(blocktype) {
594 case JBD2_DESCRIPTOR_BLOCK:
595 /* Verify checksum first */
596 if (jbd2_journal_has_csum_v2or3(journal))
597 descr_csum_size =
598 sizeof(struct jbd2_journal_block_tail);
599 if (descr_csum_size > 0 &&
600 !jbd2_descriptor_block_csum_verify(journal,
601 bh->b_data)) {
602 /*
603 * PASS_SCAN can see stale blocks due to lazy
604 * journal init. Don't error out on those yet.
605 */
606 if (pass != PASS_SCAN) {
607 pr_err("JBD2: Invalid checksum recovering block %lu in log\n",
608 next_log_block);
609 err = -EFSBADCRC;
610 brelse(bh);
611 goto failed;
612 }
613 need_check_commit_time = true;
614 jbd2_debug(1,
615 "invalid descriptor block found in %lu\n",
616 next_log_block);
617 }
618
619 /* If it is a valid descriptor block, replay it
620 * in pass REPLAY; if journal_checksums enabled, then
621 * calculate checksums in PASS_SCAN, otherwise,
622 * just skip over the blocks it describes. */
623 if (pass != PASS_REPLAY) {
624 if (pass == PASS_SCAN &&
625 jbd2_has_feature_checksum(journal) &&
626 !need_check_commit_time &&
627 !info->end_transaction) {
628 if (calc_chksums(journal, bh,
629 &next_log_block,
630 &crc32_sum)) {
631 put_bh(bh);
632 break;
633 }
634 put_bh(bh);
635 continue;
636 }
637 next_log_block += count_tags(journal, bh);
638 wrap(journal, next_log_block);
639 put_bh(bh);
640 continue;
641 }
642
643 /* A descriptor block: we can now write all of
644 * the data blocks. Yay, useful work is finally
645 * getting done here! */
646
647 tagp = &bh->b_data[sizeof(journal_header_t)];
648 while ((tagp - bh->b_data + tag_bytes)
649 <= journal->j_blocksize - descr_csum_size) {
650 unsigned long io_block;
651
652 memcpy(&tag, tagp, sizeof(tag));
653 flags = be16_to_cpu(tag.t_flags);
654
655 io_block = next_log_block++;
656 wrap(journal, next_log_block);
657 err = jread(&obh, journal, io_block);
658 if (err) {
659 /* Recover what we can, but
660 * report failure at the end. */
661 success = err;
662 printk(KERN_ERR
663 "JBD2: IO error %d recovering "
664 "block %ld in log\n",
665 err, io_block);
666 } else {
667 unsigned long long blocknr;
668
669 J_ASSERT(obh != NULL);
670 blocknr = read_tag_block(journal,
671 &tag);
672
673 /* If the block has been
674 * revoked, then we're all done
675 * here. */
676 if (jbd2_journal_test_revoke
677 (journal, blocknr,
678 next_commit_ID)) {
679 brelse(obh);
680 ++info->nr_revoke_hits;
681 goto skip_write;
682 }
683
684 /* Look for block corruption */
685 if (!jbd2_block_tag_csum_verify(
686 journal, &tag, (journal_block_tag3_t *)tagp,
687 obh->b_data, be32_to_cpu(tmp->h_sequence))) {
688 brelse(obh);
689 success = -EFSBADCRC;
690 printk(KERN_ERR "JBD2: Invalid "
691 "checksum recovering "
692 "data block %llu in "
693 "log\n", blocknr);
694 block_error = 1;
695 goto skip_write;
696 }
697
698 /* Find a buffer for the new
699 * data being restored */
700 nbh = __getblk(journal->j_fs_dev,
701 blocknr,
702 journal->j_blocksize);
703 if (nbh == NULL) {
704 printk(KERN_ERR
705 "JBD2: Out of memory "
706 "during recovery.\n");
707 err = -ENOMEM;
708 brelse(bh);
709 brelse(obh);
710 goto failed;
711 }
712
713 lock_buffer(nbh);
714 memcpy(nbh->b_data, obh->b_data,
715 journal->j_blocksize);
716 if (flags & JBD2_FLAG_ESCAPE) {
717 *((__be32 *)nbh->b_data) =
718 cpu_to_be32(JBD2_MAGIC_NUMBER);
719 }
720
721 BUFFER_TRACE(nbh, "marking dirty");
722 set_buffer_uptodate(nbh);
723 mark_buffer_dirty(nbh);
724 BUFFER_TRACE(nbh, "marking uptodate");
725 ++info->nr_replays;
726 unlock_buffer(nbh);
727 brelse(obh);
728 brelse(nbh);
729 }
730
731 skip_write:
732 tagp += tag_bytes;
733 if (!(flags & JBD2_FLAG_SAME_UUID))
734 tagp += 16;
735
736 if (flags & JBD2_FLAG_LAST_TAG)
737 break;
738 }
739
740 brelse(bh);
741 continue;
742
743 case JBD2_COMMIT_BLOCK:
744 /* How to differentiate between interrupted commit
745 * and journal corruption ?
746 *
747 * {nth transaction}
748 * Checksum Verification Failed
749 * |
750 * ____________________
751 * | |
752 * async_commit sync_commit
753 * | |
754 * | GO TO NEXT "Journal Corruption"
755 * | TRANSACTION
756 * |
757 * {(n+1)th transanction}
758 * |
759 * _______|______________
760 * | |
761 * Commit block found Commit block not found
762 * | |
763 * "Journal Corruption" |
764 * _____________|_________
765 * | |
766 * nth trans corrupt OR nth trans
767 * and (n+1)th interrupted interrupted
768 * before commit block
769 * could reach the disk.
770 * (Cannot find the difference in above
771 * mentioned conditions. Hence assume
772 * "Interrupted Commit".)
773 */
774 commit_time = be64_to_cpu(
775 ((struct commit_header *)bh->b_data)->h_commit_sec);
776 /*
777 * If need_check_commit_time is set, it means we are in
778 * PASS_SCAN and csum verify failed before. If
779 * commit_time is increasing, it's the same journal,
780 * otherwise it is stale journal block, just end this
781 * recovery.
782 */
783 if (need_check_commit_time) {
784 if (commit_time >= last_trans_commit_time) {
785 pr_err("JBD2: Invalid checksum found in transaction %u\n",
786 next_commit_ID);
787 err = -EFSBADCRC;
788 brelse(bh);
789 goto failed;
790 }
791 ignore_crc_mismatch:
792 /*
793 * It likely does not belong to same journal,
794 * just end this recovery with success.
795 */
796 jbd2_debug(1, "JBD2: Invalid checksum ignored in transaction %u, likely stale data\n",
797 next_commit_ID);
798 brelse(bh);
799 goto done;
800 }
801
802 /*
803 * Found an expected commit block: if checksums
804 * are present, verify them in PASS_SCAN; else not
805 * much to do other than move on to the next sequence
806 * number.
807 */
808 if (pass == PASS_SCAN &&
809 jbd2_has_feature_checksum(journal)) {
810 struct commit_header *cbh =
811 (struct commit_header *)bh->b_data;
812 unsigned found_chksum =
813 be32_to_cpu(cbh->h_chksum[0]);
814
815 if (info->end_transaction) {
816 journal->j_failed_commit =
817 info->end_transaction;
818 brelse(bh);
819 break;
820 }
821
822 /* Neither checksum match nor unused? */
823 if (!((crc32_sum == found_chksum &&
824 cbh->h_chksum_type ==
825 JBD2_CRC32_CHKSUM &&
826 cbh->h_chksum_size ==
827 JBD2_CRC32_CHKSUM_SIZE) ||
828 (cbh->h_chksum_type == 0 &&
829 cbh->h_chksum_size == 0 &&
830 found_chksum == 0)))
831 goto chksum_error;
832
833 crc32_sum = ~0;
834 }
835 if (pass == PASS_SCAN &&
836 !jbd2_commit_block_csum_verify(journal,
837 bh->b_data)) {
838 if (jbd2_commit_block_csum_verify_partial(
839 journal,
840 bh->b_data)) {
841 pr_notice("JBD2: Find incomplete commit block in transaction %u block %lu\n",
842 next_commit_ID, next_log_block);
843 goto chksum_ok;
844 }
845 chksum_error:
846 if (commit_time < last_trans_commit_time)
847 goto ignore_crc_mismatch;
848 info->end_transaction = next_commit_ID;
849 info->head_block = head_block;
850
851 if (!jbd2_has_feature_async_commit(journal)) {
852 journal->j_failed_commit =
853 next_commit_ID;
854 brelse(bh);
855 break;
856 }
857 }
858 if (pass == PASS_SCAN) {
859 chksum_ok:
860 last_trans_commit_time = commit_time;
861 head_block = next_log_block;
862 }
863 brelse(bh);
864 next_commit_ID++;
865 continue;
866
867 case JBD2_REVOKE_BLOCK:
868 /*
869 * Check revoke block crc in pass_scan, if csum verify
870 * failed, check commit block time later.
871 */
872 if (pass == PASS_SCAN &&
873 !jbd2_descriptor_block_csum_verify(journal,
874 bh->b_data)) {
875 jbd2_debug(1, "JBD2: invalid revoke block found in %lu\n",
876 next_log_block);
877 need_check_commit_time = true;
878 }
879
880 /* If we aren't in the REVOKE pass, then we can
881 * just skip over this block. */
882 if (pass != PASS_REVOKE) {
883 brelse(bh);
884 continue;
885 }
886
887 err = scan_revoke_records(journal, bh,
888 next_commit_ID, info);
889 brelse(bh);
890 if (err)
891 goto failed;
892 continue;
893
894 default:
895 jbd2_debug(3, "Unrecognised magic %d, end of scan.\n",
896 blocktype);
897 brelse(bh);
898 goto done;
899 }
900 }
901
902 done:
903 /*
904 * We broke out of the log scan loop: either we came to the
905 * known end of the log or we found an unexpected block in the
906 * log. If the latter happened, then we know that the "current"
907 * transaction marks the end of the valid log.
908 */
909
910 if (pass == PASS_SCAN) {
911 if (!info->end_transaction)
912 info->end_transaction = next_commit_ID;
913 if (!info->head_block)
914 info->head_block = head_block;
915 } else {
916 /* It's really bad news if different passes end up at
917 * different places (but possible due to IO errors). */
918 if (info->end_transaction != next_commit_ID) {
919 printk(KERN_ERR "JBD2: recovery pass %d ended at "
920 "transaction %u, expected %u\n",
921 pass, next_commit_ID, info->end_transaction);
922 if (!success)
923 success = -EIO;
924 }
925 }
926
927 if (jbd2_has_feature_fast_commit(journal) && pass != PASS_REVOKE) {
928 err = fc_do_one_pass(journal, info, pass);
929 if (err)
930 success = err;
931 }
932
933 if (block_error && success == 0)
934 success = -EIO;
935 return success;
936
937 failed:
938 return err;
939 }
940
941 /* Scan a revoke record, marking all blocks mentioned as revoked. */
942
scan_revoke_records(journal_t * journal,struct buffer_head * bh,tid_t sequence,struct recovery_info * info)943 static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
944 tid_t sequence, struct recovery_info *info)
945 {
946 jbd2_journal_revoke_header_t *header;
947 int offset, max;
948 unsigned csum_size = 0;
949 __u32 rcount;
950 int record_len = 4;
951
952 header = (jbd2_journal_revoke_header_t *) bh->b_data;
953 offset = sizeof(jbd2_journal_revoke_header_t);
954 rcount = be32_to_cpu(header->r_count);
955
956 if (jbd2_journal_has_csum_v2or3(journal))
957 csum_size = sizeof(struct jbd2_journal_block_tail);
958 if (rcount > journal->j_blocksize - csum_size)
959 return -EINVAL;
960 max = rcount;
961
962 if (jbd2_has_feature_64bit(journal))
963 record_len = 8;
964
965 while (offset + record_len <= max) {
966 unsigned long long blocknr;
967 int err;
968
969 if (record_len == 4)
970 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
971 else
972 blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset)));
973 offset += record_len;
974 err = jbd2_journal_set_revoke(journal, blocknr, sequence);
975 if (err)
976 return err;
977 ++info->nr_revokes;
978 }
979 return 0;
980 }
981