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Merge branches 'pxa-ian' and 'pxa-xm270' into pxa
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / fs / jbd2 / recovery.c
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 put_bh(obh);
348 }
349 return 0;
350 }
351
352 static int do_one_pass(journal_t *journal,
353 struct recovery_info *info, enum passtype pass)
354 {
355 unsigned int first_commit_ID, next_commit_ID;
356 unsigned long next_log_block;
357 int err, success = 0;
358 journal_superblock_t * sb;
359 journal_header_t * tmp;
360 struct buffer_head * bh;
361 unsigned int sequence;
362 int blocktype;
363 int tag_bytes = journal_tag_bytes(journal);
364 __u32 crc32_sum = ~0; /* Transactional Checksums */
365
366 /* Precompute the maximum metadata descriptors in a descriptor block */
367 int MAX_BLOCKS_PER_DESC;
368 MAX_BLOCKS_PER_DESC = ((journal->j_blocksize-sizeof(journal_header_t))
369 / tag_bytes);
370
371 /*
372 * First thing is to establish what we expect to find in the log
373 * (in terms of transaction IDs), and where (in terms of log
374 * block offsets): query the superblock.
375 */
376
377 sb = journal->j_superblock;
378 next_commit_ID = be32_to_cpu(sb->s_sequence);
379 next_log_block = be32_to_cpu(sb->s_start);
380
381 first_commit_ID = next_commit_ID;
382 if (pass == PASS_SCAN)
383 info->start_transaction = first_commit_ID;
384
385 jbd_debug(1, "Starting recovery pass %d\n", pass);
386
387 /*
388 * Now we walk through the log, transaction by transaction,
389 * making sure that each transaction has a commit block in the
390 * expected place. Each complete transaction gets replayed back
391 * into the main filesystem.
392 */
393
394 while (1) {
395 int flags;
396 char * tagp;
397 journal_block_tag_t * tag;
398 struct buffer_head * obh;
399 struct buffer_head * nbh;
400
401 cond_resched();
402
403 /* If we already know where to stop the log traversal,
404 * check right now that we haven't gone past the end of
405 * the log. */
406
407 if (pass != PASS_SCAN)
408 if (tid_geq(next_commit_ID, info->end_transaction))
409 break;
410
411 jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
412 next_commit_ID, next_log_block, journal->j_last);
413
414 /* Skip over each chunk of the transaction looking
415 * either the next descriptor block or the final commit
416 * record. */
417
418 jbd_debug(3, "JBD: checking block %ld\n", next_log_block);
419 err = jread(&bh, journal, next_log_block);
420 if (err)
421 goto failed;
422
423 next_log_block++;
424 wrap(journal, next_log_block);
425
426 /* What kind of buffer is it?
427 *
428 * If it is a descriptor block, check that it has the
429 * expected sequence number. Otherwise, we're all done
430 * here. */
431
432 tmp = (journal_header_t *)bh->b_data;
433
434 if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) {
435 brelse(bh);
436 break;
437 }
438
439 blocktype = be32_to_cpu(tmp->h_blocktype);
440 sequence = be32_to_cpu(tmp->h_sequence);
441 jbd_debug(3, "Found magic %d, sequence %d\n",
442 blocktype, sequence);
443
444 if (sequence != next_commit_ID) {
445 brelse(bh);
446 break;
447 }
448
449 /* OK, we have a valid descriptor block which matches
450 * all of the sequence number checks. What are we going
451 * to do with it? That depends on the pass... */
452
453 switch(blocktype) {
454 case JBD2_DESCRIPTOR_BLOCK:
455 /* If it is a valid descriptor block, replay it
456 * in pass REPLAY; if journal_checksums enabled, then
457 * calculate checksums in PASS_SCAN, otherwise,
458 * just skip over the blocks it describes. */
459 if (pass != PASS_REPLAY) {
460 if (pass == PASS_SCAN &&
461 JBD2_HAS_COMPAT_FEATURE(journal,
462 JBD2_FEATURE_COMPAT_CHECKSUM) &&
463 !info->end_transaction) {
464 if (calc_chksums(journal, bh,
465 &next_log_block,
466 &crc32_sum)) {
467 put_bh(bh);
468 break;
469 }
470 put_bh(bh);
471 continue;
472 }
473 next_log_block += count_tags(journal, bh);
474 wrap(journal, next_log_block);
475 put_bh(bh);
476 continue;
477 }
478
479 /* A descriptor block: we can now write all of
480 * the data blocks. Yay, useful work is finally
481 * getting done here! */
482
483 tagp = &bh->b_data[sizeof(journal_header_t)];
484 while ((tagp - bh->b_data + tag_bytes)
485 <= journal->j_blocksize) {
486 unsigned long io_block;
487
488 tag = (journal_block_tag_t *) tagp;
489 flags = be32_to_cpu(tag->t_flags);
490
491 io_block = next_log_block++;
492 wrap(journal, next_log_block);
493 err = jread(&obh, journal, io_block);
494 if (err) {
495 /* Recover what we can, but
496 * report failure at the end. */
497 success = err;
498 printk (KERN_ERR
499 "JBD: IO error %d recovering "
500 "block %ld in log\n",
501 err, io_block);
502 } else {
503 unsigned long long blocknr;
504
505 J_ASSERT(obh != NULL);
506 blocknr = read_tag_block(tag_bytes,
507 tag);
508
509 /* If the block has been
510 * revoked, then we're all done
511 * here. */
512 if (jbd2_journal_test_revoke
513 (journal, blocknr,
514 next_commit_ID)) {
515 brelse(obh);
516 ++info->nr_revoke_hits;
517 goto skip_write;
518 }
519
520 /* Find a buffer for the new
521 * data being restored */
522 nbh = __getblk(journal->j_fs_dev,
523 blocknr,
524 journal->j_blocksize);
525 if (nbh == NULL) {
526 printk(KERN_ERR
527 "JBD: Out of memory "
528 "during recovery.\n");
529 err = -ENOMEM;
530 brelse(bh);
531 brelse(obh);
532 goto failed;
533 }
534
535 lock_buffer(nbh);
536 memcpy(nbh->b_data, obh->b_data,
537 journal->j_blocksize);
538 if (flags & JBD2_FLAG_ESCAPE) {
539 *((__be32 *)nbh->b_data) =
540 cpu_to_be32(JBD2_MAGIC_NUMBER);
541 }
542
543 BUFFER_TRACE(nbh, "marking dirty");
544 set_buffer_uptodate(nbh);
545 mark_buffer_dirty(nbh);
546 BUFFER_TRACE(nbh, "marking uptodate");
547 ++info->nr_replays;
548 /* ll_rw_block(WRITE, 1, &nbh); */
549 unlock_buffer(nbh);
550 brelse(obh);
551 brelse(nbh);
552 }
553
554 skip_write:
555 tagp += tag_bytes;
556 if (!(flags & JBD2_FLAG_SAME_UUID))
557 tagp += 16;
558
559 if (flags & JBD2_FLAG_LAST_TAG)
560 break;
561 }
562
563 brelse(bh);
564 continue;
565
566 case JBD2_COMMIT_BLOCK:
567 /* How to differentiate between interrupted commit
568 * and journal corruption ?
569 *
570 * {nth transaction}
571 * Checksum Verification Failed
572 * |
573 * ____________________
574 * | |
575 * async_commit sync_commit
576 * | |
577 * | GO TO NEXT "Journal Corruption"
578 * | TRANSACTION
579 * |
580 * {(n+1)th transanction}
581 * |
582 * _______|______________
583 * | |
584 * Commit block found Commit block not found
585 * | |
586 * "Journal Corruption" |
587 * _____________|_________
588 * | |
589 * nth trans corrupt OR nth trans
590 * and (n+1)th interrupted interrupted
591 * before commit block
592 * could reach the disk.
593 * (Cannot find the difference in above
594 * mentioned conditions. Hence assume
595 * "Interrupted Commit".)
596 */
597
598 /* Found an expected commit block: if checksums
599 * are present verify them in PASS_SCAN; else not
600 * much to do other than move on to the next sequence
601 * number. */
602 if (pass == PASS_SCAN &&
603 JBD2_HAS_COMPAT_FEATURE(journal,
604 JBD2_FEATURE_COMPAT_CHECKSUM)) {
605 int chksum_err, chksum_seen;
606 struct commit_header *cbh =
607 (struct commit_header *)bh->b_data;
608 unsigned found_chksum =
609 be32_to_cpu(cbh->h_chksum[0]);
610
611 chksum_err = chksum_seen = 0;
612
613 if (info->end_transaction) {
614 journal->j_failed_commit =
615 info->end_transaction;
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_INCOMPAT_FEATURE(journal,
645 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)){
646 journal->j_failed_commit =
647 next_commit_ID;
648 brelse(bh);
649 break;
650 }
651 }
652 crc32_sum = ~0;
653 }
654 brelse(bh);
655 next_commit_ID++;
656 continue;
657
658 case JBD2_REVOKE_BLOCK:
659 /* If we aren't in the REVOKE pass, then we can
660 * just skip over this block. */
661 if (pass != PASS_REVOKE) {
662 brelse(bh);
663 continue;
664 }
665
666 err = scan_revoke_records(journal, bh,
667 next_commit_ID, info);
668 brelse(bh);
669 if (err)
670 goto failed;
671 continue;
672
673 default:
674 jbd_debug(3, "Unrecognised magic %d, end of scan.\n",
675 blocktype);
676 brelse(bh);
677 goto done;
678 }
679 }
680
681 done:
682 /*
683 * We broke out of the log scan loop: either we came to the
684 * known end of the log or we found an unexpected block in the
685 * log. If the latter happened, then we know that the "current"
686 * transaction marks the end of the valid log.
687 */
688
689 if (pass == PASS_SCAN) {
690 if (!info->end_transaction)
691 info->end_transaction = next_commit_ID;
692 } else {
693 /* It's really bad news if different passes end up at
694 * different places (but possible due to IO errors). */
695 if (info->end_transaction != next_commit_ID) {
696 printk (KERN_ERR "JBD: recovery pass %d ended at "
697 "transaction %u, expected %u\n",
698 pass, next_commit_ID, info->end_transaction);
699 if (!success)
700 success = -EIO;
701 }
702 }
703
704 return success;
705
706 failed:
707 return err;
708 }
709
710
711 /* Scan a revoke record, marking all blocks mentioned as revoked. */
712
713 static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
714 tid_t sequence, struct recovery_info *info)
715 {
716 jbd2_journal_revoke_header_t *header;
717 int offset, max;
718 int record_len = 4;
719
720 header = (jbd2_journal_revoke_header_t *) bh->b_data;
721 offset = sizeof(jbd2_journal_revoke_header_t);
722 max = be32_to_cpu(header->r_count);
723
724 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
725 record_len = 8;
726
727 while (offset + record_len <= max) {
728 unsigned long long blocknr;
729 int err;
730
731 if (record_len == 4)
732 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
733 else
734 blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset)));
735 offset += record_len;
736 err = jbd2_journal_set_revoke(journal, blocknr, sequence);
737 if (err)
738 return err;
739 ++info->nr_revokes;
740 }
741 return 0;
742 }
kernel source for telekom puls (alcatel/mediatek)