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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Uwe Kleine-König58862692007-05-09 07:51:49 +02002 * linux/fs/jbd/recovery.c
Mingming Caoae6ddcc2006-09-27 01:49:27 -07003 *
Linus Torvalds1da177e2005-04-16 15:20:36 -07004 * 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;
Mingming Caoae6ddcc2006-09-27 01:49:27 -070013 * part of the ext2fs journaling system.
Linus Torvalds1da177e2005-04-16 15:20:36 -070014 */
15
16#ifndef __KERNEL__
17#include "jfs_user.h"
18#else
19#include <linux/time.h>
20#include <linux/fs.h>
21#include <linux/jbd.h>
22#include <linux/errno.h>
23#include <linux/slab.h>
24#endif
25
26/*
27 * Maintain information about the progress of the recovery job, so that
Mingming Caoae6ddcc2006-09-27 01:49:27 -070028 * the different passes can carry information between them.
Linus Torvalds1da177e2005-04-16 15:20:36 -070029 */
Mingming Caoae6ddcc2006-09-27 01:49:27 -070030struct recovery_info
Linus Torvalds1da177e2005-04-16 15:20:36 -070031{
32 tid_t start_transaction;
33 tid_t end_transaction;
34
35 int nr_replays;
36 int nr_revokes;
37 int nr_revoke_hits;
38};
39
40enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY};
41static int do_one_pass(journal_t *journal,
42 struct recovery_info *info, enum passtype pass);
43static int scan_revoke_records(journal_t *, struct buffer_head *,
44 tid_t, struct recovery_info *);
45
46#ifdef __KERNEL__
47
48/* Release readahead buffers after use */
Dave Kleikampf71b2f12006-09-29 01:58:39 -070049static void journal_brelse_array(struct buffer_head *b[], int n)
Linus Torvalds1da177e2005-04-16 15:20:36 -070050{
51 while (--n >= 0)
52 brelse (b[n]);
53}
54
55
56/*
57 * When reading from the journal, we are going through the block device
58 * layer directly and so there is no readahead being done for us. We
59 * need to implement any readahead ourselves if we want it to happen at
60 * all. Recovery is basically one long sequential read, so make sure we
61 * do the IO in reasonably large chunks.
62 *
63 * This is not so critical that we need to be enormously clever about
64 * the readahead size, though. 128K is a purely arbitrary, good-enough
65 * fixed value.
66 */
67
68#define MAXBUF 8
69static int do_readahead(journal_t *journal, unsigned int start)
70{
71 int err;
72 unsigned int max, nbufs, next;
73 unsigned long blocknr;
74 struct buffer_head *bh;
75
76 struct buffer_head * bufs[MAXBUF];
77
78 /* Do up to 128K of readahead */
79 max = start + (128 * 1024 / journal->j_blocksize);
80 if (max > journal->j_maxlen)
81 max = journal->j_maxlen;
82
83 /* Do the readahead itself. We'll submit MAXBUF buffer_heads at
84 * a time to the block device IO layer. */
85
86 nbufs = 0;
87
88 for (next = start; next < max; next++) {
89 err = journal_bmap(journal, next, &blocknr);
90
91 if (err) {
92 printk (KERN_ERR "JBD: bad block at offset %u\n",
93 next);
94 goto failed;
95 }
96
97 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
98 if (!bh) {
99 err = -ENOMEM;
100 goto failed;
101 }
102
103 if (!buffer_uptodate(bh) && !buffer_locked(bh)) {
104 bufs[nbufs++] = bh;
105 if (nbufs == MAXBUF) {
106 ll_rw_block(READ, nbufs, bufs);
107 journal_brelse_array(bufs, nbufs);
108 nbufs = 0;
109 }
110 } else
111 brelse(bh);
112 }
113
114 if (nbufs)
115 ll_rw_block(READ, nbufs, bufs);
116 err = 0;
117
118failed:
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700119 if (nbufs)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 journal_brelse_array(bufs, nbufs);
121 return err;
122}
123
124#endif /* __KERNEL__ */
125
126
127/*
128 * Read a block from the journal
129 */
130
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700131static int jread(struct buffer_head **bhp, journal_t *journal,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 unsigned int offset)
133{
134 int err;
135 unsigned long blocknr;
136 struct buffer_head *bh;
137
138 *bhp = NULL;
139
140 if (offset >= journal->j_maxlen) {
141 printk(KERN_ERR "JBD: corrupted journal superblock\n");
142 return -EIO;
143 }
144
145 err = journal_bmap(journal, offset, &blocknr);
146
147 if (err) {
148 printk (KERN_ERR "JBD: bad block at offset %u\n",
149 offset);
150 return err;
151 }
152
153 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
154 if (!bh)
155 return -ENOMEM;
156
157 if (!buffer_uptodate(bh)) {
158 /* If this is a brand new buffer, start readahead.
159 Otherwise, we assume we are already reading it. */
160 if (!buffer_req(bh))
161 do_readahead(journal, offset);
162 wait_on_buffer(bh);
163 }
164
165 if (!buffer_uptodate(bh)) {
166 printk (KERN_ERR "JBD: Failed to read block at offset %u\n",
167 offset);
168 brelse(bh);
169 return -EIO;
170 }
171
172 *bhp = bh;
173 return 0;
174}
175
176
177/*
178 * Count the number of in-use tags in a journal descriptor block.
179 */
180
181static int count_tags(struct buffer_head *bh, int size)
182{
183 char * tagp;
184 journal_block_tag_t * tag;
185 int nr = 0;
186
187 tagp = &bh->b_data[sizeof(journal_header_t)];
188
189 while ((tagp - bh->b_data + sizeof(journal_block_tag_t)) <= size) {
190 tag = (journal_block_tag_t *) tagp;
191
192 nr++;
193 tagp += sizeof(journal_block_tag_t);
194 if (!(tag->t_flags & cpu_to_be32(JFS_FLAG_SAME_UUID)))
195 tagp += 16;
196
197 if (tag->t_flags & cpu_to_be32(JFS_FLAG_LAST_TAG))
198 break;
199 }
200
201 return nr;
202}
203
204
205/* Make sure we wrap around the log correctly! */
206#define wrap(journal, var) \
207do { \
208 if (var >= (journal)->j_last) \
209 var -= ((journal)->j_last - (journal)->j_first); \
210} while (0)
211
212/**
Randy Dunlap6c8bec62005-11-07 01:01:04 -0800213 * journal_recover - recovers a on-disk journal
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214 * @journal: the journal to recover
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700215 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 * The primary function for recovering the log contents when mounting a
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700217 * journaled device.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700218 *
219 * Recovery is done in three passes. In the first pass, we look for the
220 * end of the log. In the second, we assemble the list of revoke
221 * blocks. In the third and final pass, we replay any un-revoked blocks
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700222 * in the log.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 */
224int journal_recover(journal_t *journal)
225{
Hidehiro Kawai4afe9782008-10-22 14:15:00 -0700226 int err, err2;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 journal_superblock_t * sb;
228
229 struct recovery_info info;
230
231 memset(&info, 0, sizeof(info));
232 sb = journal->j_superblock;
233
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700234 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 * The journal superblock's s_start field (the current log head)
236 * is always zero if, and only if, the journal was cleanly
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700237 * unmounted.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700238 */
239
240 if (!sb->s_start) {
241 jbd_debug(1, "No recovery required, last transaction %d\n",
242 be32_to_cpu(sb->s_sequence));
243 journal->j_transaction_sequence = be32_to_cpu(sb->s_sequence) + 1;
244 return 0;
245 }
246
247 err = do_one_pass(journal, &info, PASS_SCAN);
248 if (!err)
249 err = do_one_pass(journal, &info, PASS_REVOKE);
250 if (!err)
251 err = do_one_pass(journal, &info, PASS_REPLAY);
252
Jose R. Santos9ad163a2007-10-18 23:39:23 -0700253 jbd_debug(1, "JBD: recovery, exit status %d, "
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254 "recovered transactions %u to %u\n",
255 err, info.start_transaction, info.end_transaction);
Jose R. Santos9ad163a2007-10-18 23:39:23 -0700256 jbd_debug(1, "JBD: Replayed %d and revoked %d/%d blocks\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257 info.nr_replays, info.nr_revoke_hits, info.nr_revokes);
258
259 /* Restart the log at the next transaction ID, thus invalidating
260 * any existing commit records in the log. */
261 journal->j_transaction_sequence = ++info.end_transaction;
262
263 journal_clear_revoke(journal);
Hidehiro Kawai4afe9782008-10-22 14:15:00 -0700264 err2 = sync_blockdev(journal->j_fs_dev);
265 if (!err)
266 err = err2;
267
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 return err;
269}
270
271/**
Randy Dunlap6c8bec62005-11-07 01:01:04 -0800272 * journal_skip_recovery - Start journal and wipe exiting records
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273 * @journal: journal to startup
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700274 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 * Locate any valid recovery information from the journal and set up the
276 * journal structures in memory to ignore it (presumably because the
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700277 * caller has evidence that it is out of date).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700278 * This function does'nt appear to be exorted..
279 *
280 * We perform one pass over the journal to allow us to tell the user how
281 * much recovery information is being erased, and to let us initialise
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700282 * the journal transaction sequence numbers to the next unused ID.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 */
284int journal_skip_recovery(journal_t *journal)
285{
286 int err;
287 journal_superblock_t * sb;
288
289 struct recovery_info info;
290
291 memset (&info, 0, sizeof(info));
292 sb = journal->j_superblock;
293
294 err = do_one_pass(journal, &info, PASS_SCAN);
295
296 if (err) {
297 printk(KERN_ERR "JBD: error %d scanning journal\n", err);
298 ++journal->j_transaction_sequence;
299 } else {
300#ifdef CONFIG_JBD_DEBUG
301 int dropped = info.end_transaction - be32_to_cpu(sb->s_sequence);
302#endif
Jose R. Santos9ad163a2007-10-18 23:39:23 -0700303 jbd_debug(1,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 "JBD: ignoring %d transaction%s from the journal.\n",
305 dropped, (dropped == 1) ? "" : "s");
306 journal->j_transaction_sequence = ++info.end_transaction;
307 }
308
309 journal->j_tail = 0;
310 return err;
311}
312
313static int do_one_pass(journal_t *journal,
314 struct recovery_info *info, enum passtype pass)
315{
316 unsigned int first_commit_ID, next_commit_ID;
317 unsigned long next_log_block;
318 int err, success = 0;
319 journal_superblock_t * sb;
Dave Kleikampe9ad5622006-09-27 01:49:35 -0700320 journal_header_t * tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321 struct buffer_head * bh;
322 unsigned int sequence;
323 int blocktype;
324
325 /* Precompute the maximum metadata descriptors in a descriptor block */
326 int MAX_BLOCKS_PER_DESC;
327 MAX_BLOCKS_PER_DESC = ((journal->j_blocksize-sizeof(journal_header_t))
328 / sizeof(journal_block_tag_t));
329
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700330 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331 * First thing is to establish what we expect to find in the log
332 * (in terms of transaction IDs), and where (in terms of log
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700333 * block offsets): query the superblock.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 */
335
336 sb = journal->j_superblock;
337 next_commit_ID = be32_to_cpu(sb->s_sequence);
338 next_log_block = be32_to_cpu(sb->s_start);
339
340 first_commit_ID = next_commit_ID;
341 if (pass == PASS_SCAN)
342 info->start_transaction = first_commit_ID;
343
344 jbd_debug(1, "Starting recovery pass %d\n", pass);
345
346 /*
347 * Now we walk through the log, transaction by transaction,
348 * making sure that each transaction has a commit block in the
349 * expected place. Each complete transaction gets replayed back
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700350 * into the main filesystem.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 */
352
353 while (1) {
354 int flags;
355 char * tagp;
356 journal_block_tag_t * tag;
357 struct buffer_head * obh;
358 struct buffer_head * nbh;
359
Andi Kleene86e1432008-02-06 01:40:11 -0800360 cond_resched();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361
362 /* If we already know where to stop the log traversal,
363 * check right now that we haven't gone past the end of
364 * the log. */
365
366 if (pass != PASS_SCAN)
367 if (tid_geq(next_commit_ID, info->end_transaction))
368 break;
369
370 jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
371 next_commit_ID, next_log_block, journal->j_last);
372
373 /* Skip over each chunk of the transaction looking
374 * either the next descriptor block or the final commit
375 * record. */
376
377 jbd_debug(3, "JBD: checking block %ld\n", next_log_block);
378 err = jread(&bh, journal, next_log_block);
379 if (err)
380 goto failed;
381
382 next_log_block++;
383 wrap(journal, next_log_block);
384
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700385 /* What kind of buffer is it?
386 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 * If it is a descriptor block, check that it has the
388 * expected sequence number. Otherwise, we're all done
389 * here. */
390
391 tmp = (journal_header_t *)bh->b_data;
392
393 if (tmp->h_magic != cpu_to_be32(JFS_MAGIC_NUMBER)) {
394 brelse(bh);
395 break;
396 }
397
398 blocktype = be32_to_cpu(tmp->h_blocktype);
399 sequence = be32_to_cpu(tmp->h_sequence);
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700400 jbd_debug(3, "Found magic %d, sequence %d\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 blocktype, sequence);
402
403 if (sequence != next_commit_ID) {
404 brelse(bh);
405 break;
406 }
407
408 /* OK, we have a valid descriptor block which matches
409 * all of the sequence number checks. What are we going
410 * to do with it? That depends on the pass... */
411
412 switch(blocktype) {
413 case JFS_DESCRIPTOR_BLOCK:
414 /* If it is a valid descriptor block, replay it
415 * in pass REPLAY; otherwise, just skip over the
416 * blocks it describes. */
417 if (pass != PASS_REPLAY) {
418 next_log_block +=
419 count_tags(bh, journal->j_blocksize);
420 wrap(journal, next_log_block);
421 brelse(bh);
422 continue;
423 }
424
425 /* A descriptor block: we can now write all of
426 * the data blocks. Yay, useful work is finally
427 * getting done here! */
428
429 tagp = &bh->b_data[sizeof(journal_header_t)];
430 while ((tagp - bh->b_data +sizeof(journal_block_tag_t))
431 <= journal->j_blocksize) {
432 unsigned long io_block;
433
434 tag = (journal_block_tag_t *) tagp;
435 flags = be32_to_cpu(tag->t_flags);
436
437 io_block = next_log_block++;
438 wrap(journal, next_log_block);
439 err = jread(&obh, journal, io_block);
440 if (err) {
441 /* Recover what we can, but
442 * report failure at the end. */
443 success = err;
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700444 printk (KERN_ERR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445 "JBD: IO error %d recovering "
446 "block %ld in log\n",
447 err, io_block);
448 } else {
449 unsigned long blocknr;
450
451 J_ASSERT(obh != NULL);
452 blocknr = be32_to_cpu(tag->t_blocknr);
453
454 /* If the block has been
455 * revoked, then we're all done
456 * here. */
457 if (journal_test_revoke
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700458 (journal, blocknr,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 next_commit_ID)) {
460 brelse(obh);
461 ++info->nr_revoke_hits;
462 goto skip_write;
463 }
464
465 /* Find a buffer for the new
466 * data being restored */
467 nbh = __getblk(journal->j_fs_dev,
468 blocknr,
469 journal->j_blocksize);
470 if (nbh == NULL) {
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700471 printk(KERN_ERR
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 "JBD: Out of memory "
473 "during recovery.\n");
474 err = -ENOMEM;
475 brelse(bh);
476 brelse(obh);
477 goto failed;
478 }
479
480 lock_buffer(nbh);
481 memcpy(nbh->b_data, obh->b_data,
482 journal->j_blocksize);
483 if (flags & JFS_FLAG_ESCAPE) {
Duane Griffin439aeec2008-03-19 17:00:53 -0700484 *((__be32 *)nbh->b_data) =
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 cpu_to_be32(JFS_MAGIC_NUMBER);
486 }
487
488 BUFFER_TRACE(nbh, "marking dirty");
489 set_buffer_uptodate(nbh);
490 mark_buffer_dirty(nbh);
491 BUFFER_TRACE(nbh, "marking uptodate");
492 ++info->nr_replays;
493 /* ll_rw_block(WRITE, 1, &nbh); */
494 unlock_buffer(nbh);
495 brelse(obh);
496 brelse(nbh);
497 }
498
499 skip_write:
500 tagp += sizeof(journal_block_tag_t);
501 if (!(flags & JFS_FLAG_SAME_UUID))
502 tagp += 16;
503
504 if (flags & JFS_FLAG_LAST_TAG)
505 break;
506 }
507
508 brelse(bh);
509 continue;
510
511 case JFS_COMMIT_BLOCK:
512 /* Found an expected commit block: not much to
513 * do other than move on to the next sequence
514 * number. */
515 brelse(bh);
516 next_commit_ID++;
517 continue;
518
519 case JFS_REVOKE_BLOCK:
520 /* If we aren't in the REVOKE pass, then we can
521 * just skip over this block. */
522 if (pass != PASS_REVOKE) {
523 brelse(bh);
524 continue;
525 }
526
527 err = scan_revoke_records(journal, bh,
528 next_commit_ID, info);
529 brelse(bh);
530 if (err)
531 goto failed;
532 continue;
533
534 default:
535 jbd_debug(3, "Unrecognised magic %d, end of scan.\n",
536 blocktype);
Theodore Ts'oe8f1c622006-06-25 05:47:51 -0700537 brelse(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 goto done;
539 }
540 }
541
542 done:
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700543 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 * We broke out of the log scan loop: either we came to the
545 * known end of the log or we found an unexpected block in the
546 * log. If the latter happened, then we know that the "current"
547 * transaction marks the end of the valid log.
548 */
549
550 if (pass == PASS_SCAN)
551 info->end_transaction = next_commit_ID;
552 else {
553 /* It's really bad news if different passes end up at
554 * different places (but possible due to IO errors). */
555 if (info->end_transaction != next_commit_ID) {
556 printk (KERN_ERR "JBD: recovery pass %d ended at "
557 "transaction %u, expected %u\n",
558 pass, next_commit_ID, info->end_transaction);
559 if (!success)
560 success = -EIO;
561 }
562 }
563
564 return success;
565
566 failed:
567 return err;
568}
569
570
571/* Scan a revoke record, marking all blocks mentioned as revoked. */
572
Mingming Caoae6ddcc2006-09-27 01:49:27 -0700573static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 tid_t sequence, struct recovery_info *info)
575{
576 journal_revoke_header_t *header;
577 int offset, max;
578
579 header = (journal_revoke_header_t *) bh->b_data;
580 offset = sizeof(journal_revoke_header_t);
581 max = be32_to_cpu(header->r_count);
582
583 while (offset < max) {
584 unsigned long blocknr;
585 int err;
586
587 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
588 offset += 4;
589 err = journal_set_revoke(journal, blocknr, sequence);
590 if (err)
591 return err;
592 ++info->nr_revokes;
593 }
594 return 0;
595}