ReactOS 0.4.15-dev-7887-g64a59a1
recovery.c
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1/*
2 * linux/fs/jbd/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/module.h>
20#include <linux/time.h>
21#include <linux/fs.h>
22#include <linux/jbd.h>
23#include <linux/errno.h>
24#include <linux/slab.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 */
32{
35
39};
40
42static int do_one_pass(journal_t *journal,
43 struct recovery_info *info, enum passtype pass);
44static 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 */
50static 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
70static int do_readahead(journal_t *journal, unsigned int start)
71{
72 int err;
73 unsigned int max, nbufs, next;
74 unsigned 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 = 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
119failed:
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
132static int jread(struct buffer_head **bhp, journal_t *journal,
133 unsigned int offset)
134{
135 int err;
136 unsigned 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 = 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
182static int count_tags(struct buffer_head *bh, int size)
183{
184 char * tagp;
186 int nr = 0;
187
188 tagp = &bh->b_data[sizeof(journal_header_t)];
189
190 while (((int)(tagp - bh->b_data) + (int)sizeof(journal_block_tag_t)) <= size) {
191 tag = (journal_block_tag_t *) tagp;
192
193 nr++;
194 tagp += sizeof(journal_block_tag_t);
195 if (!(tag->t_flags & cpu_to_be32(JFS_FLAG_SAME_UUID)))
196 tagp += 16;
197
198 if (tag->t_flags & cpu_to_be32(JFS_FLAG_LAST_TAG))
199 break;
200 }
201
202 return nr;
203}
204
205
206/* Make sure we wrap around the log correctly! */
207#define wrap(journal, var) \
208do { \
209 if (var >= (journal)->j_last) \
210 var -= ((journal)->j_last - (journal)->j_first); \
211} while (0)
212
225int journal_recover(journal_t *journal)
226{
227 int err;
229
230 struct recovery_info info;
231
232 memset(&info, 0, sizeof(info));
233 sb = journal->j_superblock;
234
235 /*
236 * The journal superblock's s_start field (the current log head)
237 * is always zero if, and only if, the journal was cleanly
238 * unmounted.
239 */
240
241 if (!sb->s_start) {
242 jbd_debug(1, "No recovery required, last transaction %d\n",
243 be32_to_cpu(sb->s_sequence));
244 journal->j_transaction_sequence = be32_to_cpu(sb->s_sequence) + 1;
245 return 0;
246 }
247
248 err = do_one_pass(journal, &info, PASS_SCAN);
249 if (!err)
250 err = do_one_pass(journal, &info, PASS_REVOKE);
251 if (!err)
252 err = do_one_pass(journal, &info, PASS_REPLAY);
253
254 jbd_debug(1, "JBD: recovery, exit status %d, "
255 "recovered transactions %u to %u\n",
256 err, info.start_transaction, info.end_transaction);
257 jbd_debug(1, "JBD: Replayed %d and revoked %d/%d blocks\n",
258 info.nr_replays, info.nr_revoke_hits, info.nr_revokes);
259
260 /* Restart the log at the next transaction ID, thus invalidating
261 * any existing commit records in the log. */
262 journal->j_transaction_sequence = ++info.end_transaction;
263
264 journal_clear_revoke(journal);
265 sync_blockdev(journal->j_fs_dev);
266 return err;
267}
268
282int journal_skip_recovery(journal_t *journal)
283{
284 int err;
286
287 struct recovery_info info;
288
289 memset (&info, 0, sizeof(info));
290 sb = journal->j_superblock;
291
292 err = do_one_pass(journal, &info, PASS_SCAN);
293
294 if (err) {
295 printk(KERN_ERR "JBD: error %d scanning journal\n", err);
296 ++journal->j_transaction_sequence;
297 } else {
298#ifdef CONFIG_JBD_DEBUG
299 int dropped = info.end_transaction - be32_to_cpu(sb->s_sequence);
300 jbd_debug(1,
301 "JBD: ignoring %d transaction%s from the journal.\n",
302 dropped, (dropped == 1) ? "" : "s");
303#endif
304 journal->j_transaction_sequence = ++info.end_transaction;
305 }
306
307 journal->j_tail = 0;
308 return err;
309}
310
311static int do_one_pass(journal_t *journal,
312 struct recovery_info *info, enum passtype pass)
313{
314 unsigned int first_commit_ID, next_commit_ID;
315 unsigned long next_log_block;
316 int err, success = 0;
318 journal_header_t * tmp;
319 struct buffer_head * bh;
320 unsigned int sequence;
321 int blocktype;
322
323 /* Precompute the maximum metadata descriptors in a descriptor block */
324 int MAX_BLOCKS_PER_DESC;
325 MAX_BLOCKS_PER_DESC = ((journal->j_blocksize-sizeof(journal_header_t))
326 / sizeof(journal_block_tag_t));
327
328 /*
329 * First thing is to establish what we expect to find in the log
330 * (in terms of transaction IDs), and where (in terms of log
331 * block offsets): query the superblock.
332 */
333
334 sb = journal->j_superblock;
335 next_commit_ID = be32_to_cpu(sb->s_sequence);
336 next_log_block = be32_to_cpu(sb->s_start);
337
338 first_commit_ID = next_commit_ID;
339 if (pass == PASS_SCAN)
340 info->start_transaction = first_commit_ID;
341
342 jbd_debug(1, "Starting recovery pass %d\n", pass);
343
344 /*
345 * Now we walk through the log, transaction by transaction,
346 * making sure that each transaction has a commit block in the
347 * expected place. Each complete transaction gets replayed back
348 * into the main filesystem.
349 */
350
351 while (1) {
352 int flags;
353 char * tagp;
355 struct buffer_head * obh;
356 struct buffer_head * nbh;
357
358 cond_resched();
359
360 /* If we already know where to stop the log traversal,
361 * check right now that we haven't gone past the end of
362 * the log. */
363
364 if (pass != PASS_SCAN)
365 if (tid_geq(next_commit_ID, info->end_transaction))
366 break;
367
368 jbd_debug(2, "Scanning for sequence ID %u at %lu/%lu\n",
369 next_commit_ID, next_log_block, journal->j_last);
370
371 /* Skip over each chunk of the transaction looking
372 * either the next descriptor block or the final commit
373 * record. */
374
375 jbd_debug(3, "JBD: checking block %ld\n", next_log_block);
376 err = jread(&bh, journal, next_log_block);
377 if (err)
378 goto failed;
379
380 next_log_block++;
381 wrap(journal, next_log_block);
382
383 /* What kind of buffer is it?
384 *
385 * If it is a descriptor block, check that it has the
386 * expected sequence number. Otherwise, we're all done
387 * here. */
388
389 tmp = (journal_header_t *)bh->b_data;
390
392 brelse(bh);
393 break;
394 }
395
396 blocktype = be32_to_cpu(tmp->h_blocktype);
398 jbd_debug(3, "Found magic %d, sequence %d\n",
399 blocktype, sequence);
400
401 if (sequence != next_commit_ID) {
402 brelse(bh);
403 break;
404 }
405
406 /* OK, we have a valid descriptor block which matches
407 * all of the sequence number checks. What are we going
408 * to do with it? That depends on the pass... */
409
410 switch (blocktype) {
412 /* If it is a valid descriptor block, replay it
413 * in pass REPLAY; otherwise, just skip over the
414 * blocks it describes. */
415 if (pass != PASS_REPLAY) {
416 next_log_block +=
417 count_tags(bh, journal->j_blocksize);
418 wrap(journal, next_log_block);
419 brelse(bh);
420 continue;
421 }
422
423 /* A descriptor block: we can now write all of
424 * the data blocks. Yay, useful work is finally
425 * getting done here! */
426
427 tagp = &bh->b_data[sizeof(journal_header_t)];
428 while (((int)(tagp - bh->b_data) + (int)sizeof(journal_block_tag_t))
429 <= journal->j_blocksize) {
430 unsigned long io_block;
431
432 tag = (journal_block_tag_t *) tagp;
433 flags = be32_to_cpu(tag->t_flags);
434
435 io_block = next_log_block++;
436 wrap(journal, next_log_block);
437 err = jread(&obh, journal, io_block);
438 if (err) {
439 /* Recover what we can, but
440 * report failure at the end. */
441 success = err;
443 "JBD: IO error %d recovering "
444 "block %ld in log\n",
445 err, io_block);
446 } else {
447 unsigned long blocknr;
448
449 J_ASSERT(obh != NULL);
450 blocknr = be32_to_cpu(tag->t_blocknr);
451
452 /* If the block has been
453 * revoked, then we're all done
454 * here. */
456 (journal, blocknr,
457 next_commit_ID)) {
458 brelse(obh);
459 ++info->nr_revoke_hits;
460 goto skip_write;
461 }
462
463 /* Find a buffer for the new
464 * data being restored */
465 nbh = __getblk(journal->j_fs_dev,
466 blocknr,
467 journal->j_blocksize);
468 if (nbh == NULL) {
470 "JBD: Out of memory "
471 "during recovery.\n");
472 err = -ENOMEM;
473 brelse(bh);
474 brelse(obh);
475 goto failed;
476 }
477
478 lock_buffer(nbh);
479 memcpy(nbh->b_data, obh->b_data,
480 journal->j_blocksize);
481 if (flags & JFS_FLAG_ESCAPE) {
482 *((__be32 *)bh->b_data) =
484 }
485
486 BUFFER_TRACE(nbh, "marking dirty");
487 set_buffer_uptodate(nbh);
489 BUFFER_TRACE(nbh, "marking uptodate");
490 ++info->nr_replays;
491 /* ll_rw_block(WRITE, 1, &nbh); */
492 unlock_buffer(nbh);
493 brelse(obh);
494 brelse(nbh);
495 }
496
497skip_write:
498 tagp += sizeof(journal_block_tag_t);
499 if (!(flags & JFS_FLAG_SAME_UUID))
500 tagp += 16;
501
503 break;
504 }
505
506 brelse(bh);
507 continue;
508
509 case JFS_COMMIT_BLOCK:
510 /* Found an expected commit block: not much to
511 * do other than move on to the next sequence
512 * number. */
513 brelse(bh);
514 next_commit_ID++;
515 continue;
516
517 case JFS_REVOKE_BLOCK:
518 /* If we aren't in the REVOKE pass, then we can
519 * just skip over this block. */
520 if (pass != PASS_REVOKE) {
521 brelse(bh);
522 continue;
523 }
524
525 err = scan_revoke_records(journal, bh,
526 next_commit_ID, info);
527 brelse(bh);
528 if (err)
529 goto failed;
530 continue;
531
532 default:
533 jbd_debug(3, "Unrecognised magic %d, end of scan.\n",
534 blocktype);
535 brelse(bh);
536 goto done;
537 }
538 }
539
540done:
541 /*
542 * We broke out of the log scan loop: either we came to the
543 * known end of the log or we found an unexpected block in the
544 * log. If the latter happened, then we know that the "current"
545 * transaction marks the end of the valid log.
546 */
547
548 if (pass == PASS_SCAN)
549 info->end_transaction = next_commit_ID;
550 else {
551 /* It's really bad news if different passes end up at
552 * different places (but possible due to IO errors). */
553 if (info->end_transaction != next_commit_ID) {
554 printk (KERN_ERR "JBD: recovery pass %d ended at "
555 "transaction %u, expected %u\n",
556 pass, next_commit_ID, info->end_transaction);
557 if (!success)
558 success = -EIO;
559 }
560 }
561
562 return success;
563
564failed:
565 return err;
566}
567
568
569/* Scan a revoke record, marking all blocks mentioned as revoked. */
570
571static int scan_revoke_records(journal_t *journal, struct buffer_head *bh,
573{
575 int offset, max;
576
579 max = be32_to_cpu(header->r_count);
580
581 while (offset < max) {
582 unsigned long blocknr;
583 int err;
584
585 blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset)));
586 offset += 4;
587 err = journal_set_revoke(journal, blocknr, sequence);
588 if (err)
589 return err;
590 ++info->nr_revokes;
591 }
592 return 0;
593}
static struct recvd_message * sequence
Definition: SystemMenu.c:63
#define ENOMEM
Definition: acclib.h:84
#define EIO
Definition: acclib.h:81
#define NULL
Definition: types.h:112
superblock * sb
Definition: btrfs.c:4261
r dropped
Definition: btrfs.c:3014
__u32 __bitwise __be32
Definition: types.h:67
static int scan_revoke_records(journal_t *, struct buffer_head *, tid_t, struct recovery_info *)
Definition: recovery.c:571
static int count_tags(struct buffer_head *bh, int size)
Definition: recovery.c:182
int journal_skip_recovery(journal_t *journal)
Definition: recovery.c:282
#define wrap(journal, var)
Definition: recovery.c:207
int journal_recover(journal_t *journal)
Definition: recovery.c:225
static int jread(struct buffer_head **bhp, journal_t *journal, unsigned int offset)
Definition: recovery.c:132
passtype
Definition: recovery.c:41
@ PASS_REPLAY
Definition: recovery.c:41
@ PASS_REVOKE
Definition: recovery.c:41
@ PASS_SCAN
Definition: recovery.c:41
static int do_one_pass(journal_t *journal, struct recovery_info *info, enum passtype pass)
Definition: recovery.c:311
GLuint start
Definition: gl.h:1545
GLsizeiptr size
Definition: glext.h:5919
GLdouble n
Definition: glext.h:7729
const GLenum * bufs
Definition: glext.h:6026
GLboolean GLboolean GLboolean b
Definition: glext.h:6204
GLbitfield flags
Definition: glext.h:7161
GLintptr offset
Definition: glext.h:5920
tid_t
Definition: ieframe.h:311
#define JFS_FLAG_LAST_TAG
Definition: jbd.h:210
#define JFS_REVOKE_BLOCK
Definition: jbd.h:173
struct journal_block_tag_s journal_block_tag_t
#define JFS_DESCRIPTOR_BLOCK
Definition: jbd.h:169
#define JFS_FLAG_SAME_UUID
Definition: jbd.h:208
#define JFS_COMMIT_BLOCK
Definition: jbd.h:170
#define JFS_MAGIC_NUMBER
Definition: jbd.h:159
struct journal_header_s journal_header_t
static int tid_geq(tid_t x, tid_t y)
Definition: jbd.h:1091
#define JFS_FLAG_ESCAPE
Definition: jbd.h:207
if(dx< 0)
Definition: linetemp.h:194
#define memcpy(s1, s2, n)
Definition: mkisofs.h:878
static cond_resched()
Definition: module.h:437
static void lock_buffer(struct buffer_head *bh)
Definition: module.h:1028
void unlock_buffer(struct buffer_head *bh)
Definition: linux.c:853
struct buffer_head * __getblk(struct block_device *bdev, sector_t block, unsigned long size)
Definition: linux.c:799
#define printk
Definition: module.h:231
static void wait_on_buffer(struct buffer_head *bh)
Definition: module.h:1021
void ll_rw_block(int, int, struct buffer_head *bh[])
Definition: linux.c:862
#define be32_to_cpu
Definition: module.h:157
static void brelse(struct buffer_head *bh)
Definition: module.h:955
#define cpu_to_be32
Definition: module.h:156
int sync_blockdev(struct block_device *bdev)
Definition: linux.c:919
void mark_buffer_dirty(struct buffer_head *bh)
Definition: linux.c:914
#define KERN_ERR
Definition: module.h:225
ULONG nr
Definition: thread.c:7
static unsigned __int64 next
Definition: rand_nt.c:6
#define err(...)
int journal_bmap(journal_t *journal, unsigned long blocknr, unsigned long *retp)
Definition: replay.c:484
void journal_clear_revoke(journal_t *journal)
Definition: revoke.c:689
int journal_set_revoke(journal_t *journal, unsigned long blocknr, tid_t sequence)
Definition: revoke.c:646
int journal_test_revoke(journal_t *journal, unsigned long blocknr, tid_t sequence)
Definition: revoke.c:670
static int do_readahead(mpg123_handle *fr, unsigned long newhead)
Definition: parse.c:1071
#define memset(x, y, z)
Definition: compat.h:39
char * b_data
Definition: module.h:735
__be32 h_blocktype
Definition: jbd.h:181
__be32 h_magic
Definition: jbd.h:180
__be32 h_sequence
Definition: jbd.h:182
tid_t start_transaction
Definition: recovery.c:33
int nr_revokes
Definition: recovery.c:37
int nr_revoke_hits
Definition: recovery.c:38
tid_t end_transaction
Definition: recovery.c:34
int nr_replays
Definition: recovery.c:36
Definition: ecma_167.h:138
#define max(a, b)
Definition: svc.c:63
pass
Definition: typegen.h:25
#define READ(_gif, _buf, _len)
Definition: ungif.c:107
#define success(from, fromstr, to, tostr)