?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
generic: add __FINITDATA
[wrt350n-kernel.git] / fs / jbd2 / recovery.c
blob921680663fa2771319837ad1ff24d4c8f9d8c55e
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/slab.h>
24 #include <linux/crc32.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 "JBD: 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 "JBD: corrupted journal superblock\n");
143 return -EIO;
144 }
145
146 err = jbd2_journal_bmap(journal, offset, &blocknr);
147
148 if (err) {
149 printk (KERN_ERR "JBD: 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 "JBD: 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
178 /*
179 * Count the number of in-use tags in a journal descriptor block.
180 */
181
182 static int count_tags(journal_t *journal, struct buffer_head *bh)
183 {
184 char * tagp;
185 journal_block_tag_t * tag;
186 int nr = 0, size = journal->j_blocksize;
187 int tag_bytes = journal_tag_bytes(journal);
188
189 tagp = &bh->b_data[sizeof(journal_header_t)];
190
191 while ((tagp - bh->b_data + tag_bytes) <= size) {
192 tag = (journal_block_tag_t *) tagp;
193
194 nr++;
195 tagp += tag_bytes;
196 if (!(tag->t_flags & cpu_to_be32(JBD2_FLAG_SAME_UUID)))
197 tagp += 16;
198
199 if (tag->t_flags & cpu_to_be32(JBD2_FLAG_LAST_TAG))
200 break;
201 }
202
203 return nr;
204 }
205
206
207 /* Make sure we wrap around the log correctly! */
208 #define wrap(journal, var) \
209 do { \
210 if (var >= (journal)->j_last) \
211 var -= ((journal)->j_last - (journal)->j_first); \
212 } while (0)
213
214 /**
215 * jbd2_journal_recover - recovers a on-disk journal
216 * @journal: the journal to recover
217 *
218 * The primary function for recovering the log contents when mounting a
219 * journaled device.
220 *
221 * Recovery is done in three passes. In the first pass, we look for the
222 * end of the log. In the second, we assemble the list of revoke
223 * blocks. In the third and final pass, we replay any un-revoked blocks
224 * in the log.
225 */
226 int jbd2_journal_recover(journal_t *journal)
227 {
228 int err;
229 journal_superblock_t * sb;
230
231 struct recovery_info info;
232
233 memset(&info, 0, sizeof(info));
234 sb = journal->j_superblock;
235
236 /*
237 * The journal superblock's s_start field (the current log head)
238 * is always zero if, and only if, the journal was cleanly
239 * unmounted.
240 */
241
242 if (!sb->s_start) {
243 jbd_debug(1, "No recovery required, last transaction %d\n",
244 be32_to_cpu(sb->s_sequence));
245 journal->j_transaction_sequence = be32_to_cpu(sb->s_sequence) + 1;
246 return 0;
247 }
248
249 err = do_one_pass(journal, &info, PASS_SCAN);
250 if (!err)
251 err = do_one_pass(journal, &info, PASS_REVOKE);
252 if (!err)
253 err = do_one_pass(journal, &info, PASS_REPLAY);
254
255 jbd_debug(1, "JBD: recovery, exit status %d, "
256 "recovered transactions %u to %u\n",
257 err, info.start_transaction, info.end_transaction);
258 jbd_debug(1, "JBD: Replayed %d and revoked %d/%d blocks\n",
259 info.nr_replays, info.nr_revoke_hits, info.nr_revokes);
260
261 /* Restart the log at the next transaction ID, thus invalidating
262 * any existing commit records in the log. */
263 journal->j_transaction_sequence = ++info.end_transaction;
264
265 jbd2_journal_clear_revoke(journal);
266 sync_blockdev(journal->j_fs_dev);
267 return err;
268 }
269
270 /**
271 * jbd2_journal_skip_recovery - Start journal and wipe exiting records
272 * @journal: journal to startup
273 *
274 * Locate any valid recovery information from the journal and set up the
275 * journal structures in memory to ignore it (presumably because the
276 * caller has evidence that it is out of date).
277 * This function does'nt appear to be exorted..
278 *
279 * We perform one pass over the journal to allow us to tell the user how
280 * much recovery information is being erased, and to let us initialise
281 * the journal transaction sequence numbers to the next unused ID.
282 */
283 int jbd2_journal_skip_recovery(journal_t *journal)
284 {
285 int err;
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 err = do_one_pass(journal, &info, PASS_SCAN);
294
295 if (err) {
296 printk(KERN_ERR "JBD: error %d scanning journal\n", err);
297 ++journal->j_transaction_sequence;
298 } else {
299 #ifdef CONFIG_JBD2_DEBUG
300 int dropped = info.end_transaction - be32_to_cpu(sb->s_sequence);
301 #endif
302 jbd_debug(1,
303 "JBD: ignoring %d transaction%s from the journal.\n",
304 dropped, (dropped == 1) ? "" : "s");
305 journal->j_transaction_sequence = ++info.end_transaction;
306 }
307
308 journal->j_tail = 0;
309 return err;
310 }
311
312 static inline unsigned long long read_tag_block(int tag_bytes, journal_block_tag_t *tag)
313 {
314 unsigned long long block = be32_to_cpu(tag->t_blocknr);
315 if (tag_bytes > JBD2_TAG_SIZE32)
316 block |= (u64)be32_to_cpu(tag->t_blocknr_high) << 32;
317 return block;
318 }
319
320 /*
321 * calc_chksums calculates the checksums for the blocks described in the
322 * descriptor block.
323 */
324 static int calc_chksums(journal_t *journal, struct buffer_head *bh,
325 unsigned long *next_log_block, __u32 *crc32_sum)
326 {
327 int i, num_blks, err;
328 unsigned long io_block;
329 struct buffer_head *obh;
330
331 num_blks = count_tags(journal, bh);
332 /* Calculate checksum of the descriptor block. */
333 *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size);
334
335 for (i = 0; i < num_blks; i++) {
336 io_block = (*next_log_block)++;
337 wrap(journal, *next_log_block);
338 err = jread(&obh, journal, io_block);
339 if (err) {
340 printk(KERN_ERR "JBD: IO error %d recovering block "
341 "%lu in log\n", err, io_block);
342 return 1;
343 } else {
344 *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data,
345 obh->b_size);
346 }
347 }
348 return 0;
349 }
350
351 static int do_one_pass(journal_t *journal,
352 struct recovery_info *info, enum passtype pass)
353 {
354 unsigned int first_commit_ID, next_commit_ID;
355 unsigned long next_log_block;
356 int err, success = 0;
357 journal_superblock_t * sb;
358 journal_header_t * tmp;
359 struct buffer_head * bh;
360 unsigned int sequence;
361 int blocktype;
362 int tag_bytes = journal_tag_bytes(journal);
363 __u32 crc32_sum = ~0; /* Transactional Checksums */
364
365 /* Precompute the maximum metadata descriptors in a descriptor block */
366 int MAX_BLOCKS_PER_DESC;
367 MAX_BLOCKS_PER_DESC = ((journal->j_blocksize-sizeof(journal_header_t))
368 / tag_bytes);
369
370 /*
371 * First thing is to establish what we expect to find in the log
372 * (in terms of transaction IDs), and where (in terms of log
373 * block offsets): query the superblock.
374 */
375
376 sb = journal->j_superblock;
377 next_commit_ID = be32_to_cpu(sb->s_sequence);
378 next_log_block = be32_to_cpu(sb->s_start);
379
380 first_commit_ID = next_commit_ID;
381 if (pass == PASS_SCAN)
382 info->start_transaction = first_commit_ID;
383
384 jbd_debug(1, "Starting recovery pass %d\n", pass);
385
386 /*
387 * Now we walk through the log, transaction by transaction,
388 * making sure that each transaction has a commit block in the
389 * expected place. Each complete transaction gets replayed back
390 * into the main filesystem.
391 */
392
393 while (1) {
394 int flags;
395 char * tagp;
396 journal_block_tag_t * tag;
397 struct buffer_head * obh;
398 struct buffer_head * nbh;
399
400 cond_resched(); /* We're under lock_kernel() */
401
402 /* If we already know where to stop the log traversal,
403 * check right now that we haven't gone past the end of
404 * the log. */
405
406 if (pass != PASS_SCAN)
407 if (tid_geq(next_commit_ID, info->end_transaction))
408 break;
409
410 jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
411 next_commit_ID, next_log_block, journal->j_last);
412
413 /* Skip over each chunk of the transaction looking
414 * either the next descriptor block or the final commit
415 * record. */
416
417 jbd_debug(3, "JBD: checking block %ld\n", next_log_block);
418 err = jread(&bh, journal, next_log_block);
419 if (err)
420 goto failed;
421
422 next_log_block++;
423 wrap(journal, next_log_block);
424
425 /* What kind of buffer is it?
426 *
427 * If it is a descriptor block, check that it has the
428 * expected sequence number. Otherwise, we're all done
429 * here. */
430
431 tmp = (journal_header_t *)bh->b_data;
432
433 if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) {
434 brelse(bh);
435 break;
436 }
437
438 blocktype = be32_to_cpu(tmp->h_blocktype);
439 sequence = be32_to_cpu(tmp->h_sequence);
440 jbd_debug(3, "Found magic %d, sequence %d\n",
441 blocktype, sequence);
442
443 if (sequence != next_commit_ID) {
444 brelse(bh);
445 break;
446 }
447
448 /* OK, we have a valid descriptor block which matches
449 * all of the sequence number checks. What are we going
450 * to do with it? That depends on the pass... */
451
452 switch(blocktype) {
453 case JBD2_DESCRIPTOR_BLOCK:
454 /* If it is a valid descriptor block, replay it
455 * in pass REPLAY; if journal_checksums enabled, then
456 * calculate checksums in PASS_SCAN, otherwise,
457 * just skip over the blocks it describes. */
458 if (pass != PASS_REPLAY) {
459 if (pass == PASS_SCAN &&
460 JBD2_HAS_COMPAT_FEATURE(journal,
461 JBD2_FEATURE_COMPAT_CHECKSUM) &&
462 !info->end_transaction) {
463 if (calc_chksums(journal, bh,
464 &next_log_block,
465 &crc32_sum)) {
466 put_bh(bh);
467 break;
468 }
469 put_bh(bh);
470 continue;
471 }
472 next_log_block += count_tags(journal, bh);
473 wrap(journal, next_log_block);
474 put_bh(bh);
475 continue;
476 }
477
478 /* A descriptor block: we can now write all of
479 * the data blocks. Yay, useful work is finally
480 * getting done here! */
481
482 tagp = &bh->b_data[sizeof(journal_header_t)];
483 while ((tagp - bh->b_data + tag_bytes)
484 <= journal->j_blocksize) {
485 unsigned long io_block;
486
487 tag = (journal_block_tag_t *) tagp;
488 flags = be32_to_cpu(tag->t_flags);
489
490 io_block = next_log_block++;
491 wrap(journal, next_log_block);
492 err = jread(&obh, journal, io_block);
493 if (err) {
494 /* Recover what we can, but
495 * report failure at the end. */
496 success = err;
497 printk (KERN_ERR
498 "JBD: IO error %d recovering "
499 "block %ld in log\n",
500 err, io_block);
501 } else {
502 unsigned long long blocknr;
503
504 J_ASSERT(obh != NULL);
505 blocknr = read_tag_block(tag_bytes,
506 tag);
507
508 /* If the block has been
509 * revoked, then we're all done
510 * here. */
511 if (jbd2_journal_test_revoke
512 (journal, blocknr,
513 next_commit_ID)) {
514 brelse(obh);
515 ++info->nr_revoke_hits;
516 goto skip_write;
517 }
518
519 /* Find a buffer for the new
520 * data being restored */
521 nbh = __getblk(journal->j_fs_dev,
522 blocknr,
523 journal->j_blocksize);
524 if (nbh == NULL) {
525 printk(KERN_ERR
526 "JBD: Out of memory "
527 "during recovery.\n");
528 err = -ENOMEM;
529 brelse(bh);
530 brelse(obh);
531 goto failed;
532 }
533
534 lock_buffer(nbh);
535 memcpy(nbh->b_data, obh->b_data,
536 journal->j_blocksize);
537 if (flags & JBD2_FLAG_ESCAPE) {
538 *((__be32 *)bh->b_data) =
539 cpu_to_be32(JBD2_MAGIC_NUMBER);
540 }
541
542 BUFFER_TRACE(nbh, "marking dirty");
543 set_buffer_uptodate(nbh);
544 mark_buffer_dirty(nbh);
545 BUFFER_TRACE(nbh, "marking uptodate");
546 ++info->nr_replays;
547 /* ll_rw_block(WRITE, 1, &nbh); */
548 unlock_buffer(nbh);
549 brelse(obh);
550 brelse(nbh);
551 }
552
553 skip_write:
554 tagp += tag_bytes;
555 if (!(flags & JBD2_FLAG_SAME_UUID))
556 tagp += 16;
557
558 if (flags & JBD2_FLAG_LAST_TAG)
559 break;
560 }
561
562 brelse(bh);
563 continue;
564
565 case JBD2_COMMIT_BLOCK:
566 /* How to differentiate between interrupted commit
567 * and journal corruption ?
568 *
569 * {nth transaction}
570 * Checksum Verification Failed
571 * |
572 * ____________________
573 * | |
574 * async_commit sync_commit
575 * | |
576 * | GO TO NEXT "Journal Corruption"
577 * | TRANSACTION
578 * |
579 * {(n+1)th transanction}
580 * |
581 * _______|______________
582 * | |
583 * Commit block found Commit block not found
584 * | |
585 * "Journal Corruption" |
586 * _____________|_________
587 * | |
588 * nth trans corrupt OR nth trans
589 * and (n+1)th interrupted interrupted
590 * before commit block
591 * could reach the disk.
592 * (Cannot find the difference in above
593 * mentioned conditions. Hence assume
594 * "Interrupted Commit".)
595 */
596
597 /* Found an expected commit block: if checksums
598 * are present verify them in PASS_SCAN; else not
599 * much to do other than move on to the next sequence
600 * number. */
601 if (pass == PASS_SCAN &&
602 JBD2_HAS_COMPAT_FEATURE(journal,
603 JBD2_FEATURE_COMPAT_CHECKSUM)) {
604 int chksum_err, chksum_seen;
605 struct commit_header *cbh =
606 (struct commit_header *)bh->b_data;
607 unsigned found_chksum =
608 be32_to_cpu(cbh->h_chksum[0]);
609
610 chksum_err = chksum_seen = 0;
611
612 if (info->end_transaction) {
613 printk(KERN_ERR "JBD: Transaction %u "
614 "found to be corrupt.\n",
615 next_commit_ID - 1);
616 brelse(bh);
617 break;
618 }
619
620 if (crc32_sum == found_chksum &&
621 cbh->h_chksum_type == JBD2_CRC32_CHKSUM &&
622 cbh->h_chksum_size ==
623 JBD2_CRC32_CHKSUM_SIZE)
624 chksum_seen = 1;
625 else if (!(cbh->h_chksum_type == 0 &&
626 cbh->h_chksum_size == 0 &&
627 found_chksum == 0 &&
628 !chksum_seen))
629 /*
630 * If fs is mounted using an old kernel and then
631 * kernel with journal_chksum is used then we
632 * get a situation where the journal flag has
633 * checksum flag set but checksums are not
634 * present i.e chksum = 0, in the individual
635 * commit blocks.
636 * Hence to avoid checksum failures, in this
637 * situation, this extra check is added.
638 */
639 chksum_err = 1;
640
641 if (chksum_err) {
642 info->end_transaction = next_commit_ID;
643
644 if (!JBD2_HAS_COMPAT_FEATURE(journal,
645 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)){
646 printk(KERN_ERR
647 "JBD: Transaction %u "
648 "found to be corrupt.\n",
649 next_commit_ID);
650 brelse(bh);
651 break;
652 }
653 }
654 crc32_sum = ~0;
655 }
656 brelse(bh);
657 next_commit_ID++;
658 continue;
659
660 case JBD2_REVOKE_BLOCK:
661 /* If we aren't in the REVOKE pass, then we can
662 * just skip over this block. */
663 if (pass != PASS_REVOKE) {
664 brelse(bh);
665 continue;
666 }
667
668 err = scan_revoke_records(journal, bh,
669 next_commit_ID, info);
670 brelse(bh);
671 if (err)
672 goto failed;
673 continue;
674
675 default:
676 jbd_debug(3, "Unrecognised magic %d, end of scan.\n",
677 blocktype);
678 brelse(bh);
679 goto done;
680 }
681 }
682
683 done:
684 /*
685 * We broke out of the log scan loop: either we came to the
686 * known end of the log or we found an unexpected block in the
687 * log. If the latter happened, then we know that the "current"
688 * transaction marks the end of the valid log.
689 */
690
691 if (pass == PASS_SCAN) {
692 if (!info->end_transaction)
693 info->end_transaction = next_commit_ID;
694 } else {
695 /* It's really bad news if different passes end up at
696 * different places (but possible due to IO errors). */
697 if (info->end_transaction != next_commit_ID) {
698 printk (KERN_ERR "JBD: recovery pass %d ended at "
699 "transaction %u, expected %u\n",
700 pass, next_commit_ID, info->end_transaction);
701 if (!success)
702 success = -EIO;
703 }
704 }
705
706 return success;
707
708 failed:
709 return err;
710 }
711
712
713 /* Scan a revoke record, marking all blocks mentioned as revoked. */
714
715 static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
716 tid_t sequence, struct recovery_info *info)
717 {
718 jbd2_journal_revoke_header_t *header;
719 int offset, max;
720 int record_len = 4;
721
722 header = (jbd2_journal_revoke_header_t *) bh->b_data;
723 offset = sizeof(jbd2_journal_revoke_header_t);
724 max = be32_to_cpu(header->r_count);
725
726 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
727 record_len = 8;
728
729 while (offset + record_len <= max) {
730 unsigned long long blocknr;
731 int err;
732
733 if (record_len == 4)
734 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
735 else
736 blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset)));
737 offset += record_len;
738 err = jbd2_journal_set_revoke(journal, blocknr, sequence);
739 if (err)
740 return err;
741 ++info->nr_revokes;
742 }
743 return 0;
744 }
WRT350N Kernel Patches