Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
58862699 | 2 | * linux/fs/jbd/recovery.c |
ae6ddcc5 | 3 | * |
1da177e4 LT |
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; | |
ae6ddcc5 | 13 | * part of the ext2fs journaling system. |
1da177e4 LT |
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/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 | |
ae6ddcc5 | 28 | * the different passes can carry information between them. |
1da177e4 | 29 | */ |
ae6ddcc5 | 30 | struct recovery_info |
1da177e4 LT |
31 | { |
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 | ||
40 | enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY}; | |
41 | static int do_one_pass(journal_t *journal, | |
42 | struct recovery_info *info, enum passtype pass); | |
43 | static 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 */ | |
f71b2f10 | 49 | static void journal_brelse_array(struct buffer_head *b[], int n) |
1da177e4 LT |
50 | { |
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 | |
69 | static 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 | ||
118 | failed: | |
ae6ddcc5 | 119 | if (nbufs) |
1da177e4 LT |
120 | 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 | ||
ae6ddcc5 | 131 | static int jread(struct buffer_head **bhp, journal_t *journal, |
1da177e4 LT |
132 | 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 | ||
181 | static 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) \ | |
207 | do { \ | |
208 | if (var >= (journal)->j_last) \ | |
209 | var -= ((journal)->j_last - (journal)->j_first); \ | |
210 | } while (0) | |
211 | ||
212 | /** | |
6c8bec6d | 213 | * journal_recover - recovers a on-disk journal |
1da177e4 | 214 | * @journal: the journal to recover |
ae6ddcc5 | 215 | * |
1da177e4 | 216 | * The primary function for recovering the log contents when mounting a |
ae6ddcc5 | 217 | * journaled device. |
1da177e4 LT |
218 | * |
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 | |
ae6ddcc5 | 222 | * in the log. |
1da177e4 LT |
223 | */ |
224 | int journal_recover(journal_t *journal) | |
225 | { | |
4afe9785 | 226 | int err, err2; |
1da177e4 LT |
227 | journal_superblock_t * sb; |
228 | ||
229 | struct recovery_info info; | |
230 | ||
231 | memset(&info, 0, sizeof(info)); | |
232 | sb = journal->j_superblock; | |
233 | ||
ae6ddcc5 | 234 | /* |
1da177e4 LT |
235 | * The journal superblock's s_start field (the current log head) |
236 | * is always zero if, and only if, the journal was cleanly | |
ae6ddcc5 | 237 | * unmounted. |
1da177e4 LT |
238 | */ |
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 | ||
9ad163ae | 253 | jbd_debug(1, "JBD: recovery, exit status %d, " |
1da177e4 LT |
254 | "recovered transactions %u to %u\n", |
255 | err, info.start_transaction, info.end_transaction); | |
9ad163ae | 256 | jbd_debug(1, "JBD: Replayed %d and revoked %d/%d blocks\n", |
1da177e4 LT |
257 | 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); | |
4afe9785 HK |
264 | err2 = sync_blockdev(journal->j_fs_dev); |
265 | if (!err) | |
266 | err = err2; | |
267 | ||
1da177e4 LT |
268 | return err; |
269 | } | |
270 | ||
271 | /** | |
6c8bec6d | 272 | * journal_skip_recovery - Start journal and wipe exiting records |
1da177e4 | 273 | * @journal: journal to startup |
ae6ddcc5 | 274 | * |
1da177e4 LT |
275 | * Locate any valid recovery information from the journal and set up the |
276 | * journal structures in memory to ignore it (presumably because the | |
ae6ddcc5 | 277 | * caller has evidence that it is out of date). |
1da177e4 LT |
278 | * 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 | |
ae6ddcc5 | 282 | * the journal transaction sequence numbers to the next unused ID. |
1da177e4 LT |
283 | */ |
284 | int 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 | |
9ad163ae | 303 | jbd_debug(1, |
1da177e4 LT |
304 | "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 | ||
313 | static 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; | |
e9ad5620 | 320 | journal_header_t * tmp; |
1da177e4 LT |
321 | 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 | ||
ae6ddcc5 | 330 | /* |
1da177e4 LT |
331 | * 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 | |
ae6ddcc5 | 333 | * block offsets): query the superblock. |
1da177e4 LT |
334 | */ |
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 | |
ae6ddcc5 | 350 | * into the main filesystem. |
1da177e4 LT |
351 | */ |
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 | ||
e86e1438 | 360 | cond_resched(); |
1da177e4 LT |
361 | |
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 | ||
ae6ddcc5 MC |
385 | /* What kind of buffer is it? |
386 | * | |
1da177e4 LT |
387 | * 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); | |
ae6ddcc5 | 400 | jbd_debug(3, "Found magic %d, sequence %d\n", |
1da177e4 LT |
401 | 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; | |
ae6ddcc5 | 444 | printk (KERN_ERR |
1da177e4 LT |
445 | "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 | |
ae6ddcc5 | 458 | (journal, blocknr, |
1da177e4 LT |
459 | 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) { | |
ae6ddcc5 | 471 | printk(KERN_ERR |
1da177e4 LT |
472 | "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) { | |
439aeec6 | 484 | *((__be32 *)nbh->b_data) = |
1da177e4 LT |
485 | 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); | |
e8f1c622 | 537 | brelse(bh); |
1da177e4 LT |
538 | goto done; |
539 | } | |
540 | } | |
541 | ||
542 | done: | |
ae6ddcc5 | 543 | /* |
1da177e4 LT |
544 | * 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 | ||
ae6ddcc5 | 573 | static int scan_revoke_records(journal_t *journal, struct buffer_head *bh, |
1da177e4 LT |
574 | 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 | } |