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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Uwe Zeisbergerf30c2262006-10-03 23:01:26 +02002 * linux/fs/jbd/commit.c
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
5 *
6 * Copyright 1998 Red Hat corp --- 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 commit routines for the generic filesystem journaling code;
13 * part of the ext2fs journaling system.
14 */
15
16#include <linux/time.h>
17#include <linux/fs.h>
18#include <linux/jbd.h>
19#include <linux/errno.h>
20#include <linux/slab.h>
21#include <linux/mm.h>
22#include <linux/pagemap.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
24/*
25 * Default IO end handler for temporary BJ_IO buffer_heads.
26 */
27static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
28{
29 BUFFER_TRACE(bh, "");
30 if (uptodate)
31 set_buffer_uptodate(bh);
32 else
33 clear_buffer_uptodate(bh);
34 unlock_buffer(bh);
35}
36
37/*
38 * When an ext3-ordered file is truncated, it is possible that many pages are
39 * not sucessfully freed, because they are attached to a committing transaction.
40 * After the transaction commits, these pages are left on the LRU, with no
41 * ->mapping, and with attached buffers. These pages are trivially reclaimable
42 * by the VM, but their apparent absence upsets the VM accounting, and it makes
43 * the numbers in /proc/meminfo look odd.
44 *
45 * So here, we have a buffer which has just come off the forget list. Look to
46 * see if we can strip all buffers from the backing page.
47 *
48 * Called under lock_journal(), and possibly under journal_datalist_lock. The
49 * caller provided us with a ref against the buffer, and we drop that here.
50 */
51static void release_buffer_page(struct buffer_head *bh)
52{
53 struct page *page;
54
55 if (buffer_dirty(bh))
56 goto nope;
57 if (atomic_read(&bh->b_count) != 1)
58 goto nope;
59 page = bh->b_page;
60 if (!page)
61 goto nope;
62 if (page->mapping)
63 goto nope;
64
65 /* OK, it's a truncated page */
66 if (TestSetPageLocked(page))
67 goto nope;
68
69 page_cache_get(page);
70 __brelse(bh);
71 try_to_free_buffers(page);
72 unlock_page(page);
73 page_cache_release(page);
74 return;
75
76nope:
77 __brelse(bh);
78}
79
80/*
81 * Try to acquire jbd_lock_bh_state() against the buffer, when j_list_lock is
82 * held. For ranking reasons we must trylock. If we lose, schedule away and
83 * return 0. j_list_lock is dropped in this case.
84 */
85static int inverted_lock(journal_t *journal, struct buffer_head *bh)
86{
87 if (!jbd_trylock_bh_state(bh)) {
88 spin_unlock(&journal->j_list_lock);
89 schedule();
90 return 0;
91 }
92 return 1;
93}
94
95/* Done it all: now write the commit record. We should have
96 * cleaned up our previous buffers by now, so if we are in abort
97 * mode we can now just skip the rest of the journal write
98 * entirely.
99 *
100 * Returns 1 if the journal needs to be aborted or 0 on success
101 */
102static int journal_write_commit_record(journal_t *journal,
103 transaction_t *commit_transaction)
104{
105 struct journal_head *descriptor;
106 struct buffer_head *bh;
107 int i, ret;
108 int barrier_done = 0;
109
110 if (is_journal_aborted(journal))
111 return 0;
112
113 descriptor = journal_get_descriptor_buffer(journal);
114 if (!descriptor)
115 return 1;
116
117 bh = jh2bh(descriptor);
118
119 /* AKPM: buglet - add `i' to tmp! */
120 for (i = 0; i < bh->b_size; i += 512) {
121 journal_header_t *tmp = (journal_header_t*)bh->b_data;
122 tmp->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
123 tmp->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK);
124 tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
125 }
126
127 JBUFFER_TRACE(descriptor, "write commit block");
128 set_buffer_dirty(bh);
129 if (journal->j_flags & JFS_BARRIER) {
130 set_buffer_ordered(bh);
131 barrier_done = 1;
132 }
133 ret = sync_dirty_buffer(bh);
134 /* is it possible for another commit to fail at roughly
135 * the same time as this one? If so, we don't want to
136 * trust the barrier flag in the super, but instead want
137 * to remember if we sent a barrier request
138 */
139 if (ret == -EOPNOTSUPP && barrier_done) {
140 char b[BDEVNAME_SIZE];
141
142 printk(KERN_WARNING
143 "JBD: barrier-based sync failed on %s - "
144 "disabling barriers\n",
145 bdevname(journal->j_dev, b));
146 spin_lock(&journal->j_state_lock);
147 journal->j_flags &= ~JFS_BARRIER;
148 spin_unlock(&journal->j_state_lock);
149
150 /* And try again, without the barrier */
151 clear_buffer_ordered(bh);
152 set_buffer_uptodate(bh);
153 set_buffer_dirty(bh);
154 ret = sync_dirty_buffer(bh);
155 }
156 put_bh(bh); /* One for getblk() */
157 journal_put_journal_head(descriptor);
158
159 return (ret == -EIO);
160}
161
Jan Kara3998b932006-09-25 23:30:53 -0700162static void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
163{
164 int i;
165
166 for (i = 0; i < bufs; i++) {
167 wbuf[i]->b_end_io = end_buffer_write_sync;
168 /* We use-up our safety reference in submit_bh() */
169 submit_bh(WRITE, wbuf[i]);
170 }
171}
172
173/*
174 * Submit all the data buffers to disk
175 */
176static void journal_submit_data_buffers(journal_t *journal,
177 transaction_t *commit_transaction)
178{
179 struct journal_head *jh;
180 struct buffer_head *bh;
181 int locked;
182 int bufs = 0;
183 struct buffer_head **wbuf = journal->j_wbuf;
184
185 /*
186 * Whenever we unlock the journal and sleep, things can get added
187 * onto ->t_sync_datalist, so we have to keep looping back to
188 * write_out_data until we *know* that the list is empty.
189 *
190 * Cleanup any flushed data buffers from the data list. Even in
191 * abort mode, we want to flush this out as soon as possible.
192 */
193write_out_data:
194 cond_resched();
195 spin_lock(&journal->j_list_lock);
196
197 while (commit_transaction->t_sync_datalist) {
198 jh = commit_transaction->t_sync_datalist;
199 bh = jh2bh(jh);
200 locked = 0;
201
202 /* Get reference just to make sure buffer does not disappear
203 * when we are forced to drop various locks */
204 get_bh(bh);
205 /* If the buffer is dirty, we need to submit IO and hence
206 * we need the buffer lock. We try to lock the buffer without
207 * blocking. If we fail, we need to drop j_list_lock and do
208 * blocking lock_buffer().
209 */
210 if (buffer_dirty(bh)) {
211 if (test_set_buffer_locked(bh)) {
212 BUFFER_TRACE(bh, "needs blocking lock");
213 spin_unlock(&journal->j_list_lock);
214 /* Write out all data to prevent deadlocks */
215 journal_do_submit_data(wbuf, bufs);
216 bufs = 0;
217 lock_buffer(bh);
218 spin_lock(&journal->j_list_lock);
219 }
220 locked = 1;
221 }
222 /* We have to get bh_state lock. Again out of order, sigh. */
223 if (!inverted_lock(journal, bh)) {
224 jbd_lock_bh_state(bh);
225 spin_lock(&journal->j_list_lock);
226 }
227 /* Someone already cleaned up the buffer? */
228 if (!buffer_jbd(bh)
229 || jh->b_transaction != commit_transaction
230 || jh->b_jlist != BJ_SyncData) {
231 jbd_unlock_bh_state(bh);
232 if (locked)
233 unlock_buffer(bh);
234 BUFFER_TRACE(bh, "already cleaned up");
235 put_bh(bh);
236 continue;
237 }
238 if (locked && test_clear_buffer_dirty(bh)) {
239 BUFFER_TRACE(bh, "needs writeout, adding to array");
240 wbuf[bufs++] = bh;
241 __journal_file_buffer(jh, commit_transaction,
242 BJ_Locked);
243 jbd_unlock_bh_state(bh);
244 if (bufs == journal->j_wbufsize) {
245 spin_unlock(&journal->j_list_lock);
246 journal_do_submit_data(wbuf, bufs);
247 bufs = 0;
248 goto write_out_data;
249 }
Hisashi Hifumi6f5a9da2006-12-22 01:11:50 -0800250 } else if (!locked && buffer_locked(bh)) {
251 __journal_file_buffer(jh, commit_transaction,
252 BJ_Locked);
253 jbd_unlock_bh_state(bh);
254 put_bh(bh);
255 } else {
Jan Kara3998b932006-09-25 23:30:53 -0700256 BUFFER_TRACE(bh, "writeout complete: unfile");
257 __journal_unfile_buffer(jh);
258 jbd_unlock_bh_state(bh);
259 if (locked)
260 unlock_buffer(bh);
261 journal_remove_journal_head(bh);
262 /* Once for our safety reference, once for
263 * journal_remove_journal_head() */
264 put_bh(bh);
265 put_bh(bh);
266 }
267
268 if (lock_need_resched(&journal->j_list_lock)) {
269 spin_unlock(&journal->j_list_lock);
270 goto write_out_data;
271 }
272 }
273 spin_unlock(&journal->j_list_lock);
274 journal_do_submit_data(wbuf, bufs);
275}
276
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277/*
278 * journal_commit_transaction
279 *
280 * The primary function for committing a transaction to the log. This
281 * function is called by the journal thread to begin a complete commit.
282 */
283void journal_commit_transaction(journal_t *journal)
284{
285 transaction_t *commit_transaction;
286 struct journal_head *jh, *new_jh, *descriptor;
287 struct buffer_head **wbuf = journal->j_wbuf;
288 int bufs;
289 int flags;
290 int err;
291 unsigned long blocknr;
292 char *tagp = NULL;
293 journal_header_t *header;
294 journal_block_tag_t *tag = NULL;
295 int space_left = 0;
296 int first_tag = 0;
297 int tag_flag;
298 int i;
299
300 /*
301 * First job: lock down the current transaction and wait for
302 * all outstanding updates to complete.
303 */
304
305#ifdef COMMIT_STATS
306 spin_lock(&journal->j_list_lock);
307 summarise_journal_usage(journal);
308 spin_unlock(&journal->j_list_lock);
309#endif
310
311 /* Do we need to erase the effects of a prior journal_flush? */
312 if (journal->j_flags & JFS_FLUSHED) {
313 jbd_debug(3, "super block updated\n");
314 journal_update_superblock(journal, 1);
315 } else {
316 jbd_debug(3, "superblock not updated\n");
317 }
318
319 J_ASSERT(journal->j_running_transaction != NULL);
320 J_ASSERT(journal->j_committing_transaction == NULL);
321
322 commit_transaction = journal->j_running_transaction;
323 J_ASSERT(commit_transaction->t_state == T_RUNNING);
324
325 jbd_debug(1, "JBD: starting commit of transaction %d\n",
326 commit_transaction->t_tid);
327
328 spin_lock(&journal->j_state_lock);
329 commit_transaction->t_state = T_LOCKED;
330
331 spin_lock(&commit_transaction->t_handle_lock);
332 while (commit_transaction->t_updates) {
333 DEFINE_WAIT(wait);
334
335 prepare_to_wait(&journal->j_wait_updates, &wait,
336 TASK_UNINTERRUPTIBLE);
337 if (commit_transaction->t_updates) {
338 spin_unlock(&commit_transaction->t_handle_lock);
339 spin_unlock(&journal->j_state_lock);
340 schedule();
341 spin_lock(&journal->j_state_lock);
342 spin_lock(&commit_transaction->t_handle_lock);
343 }
344 finish_wait(&journal->j_wait_updates, &wait);
345 }
346 spin_unlock(&commit_transaction->t_handle_lock);
347
348 J_ASSERT (commit_transaction->t_outstanding_credits <=
349 journal->j_max_transaction_buffers);
350
351 /*
352 * First thing we are allowed to do is to discard any remaining
353 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
354 * that there are no such buffers: if a large filesystem
355 * operation like a truncate needs to split itself over multiple
356 * transactions, then it may try to do a journal_restart() while
357 * there are still BJ_Reserved buffers outstanding. These must
358 * be released cleanly from the current transaction.
359 *
360 * In this case, the filesystem must still reserve write access
361 * again before modifying the buffer in the new transaction, but
362 * we do not require it to remember exactly which old buffers it
363 * has reserved. This is consistent with the existing behaviour
364 * that multiple journal_get_write_access() calls to the same
365 * buffer are perfectly permissable.
366 */
367 while (commit_transaction->t_reserved_list) {
368 jh = commit_transaction->t_reserved_list;
369 JBUFFER_TRACE(jh, "reserved, unused: refile");
370 /*
371 * A journal_get_undo_access()+journal_release_buffer() may
372 * leave undo-committed data.
373 */
374 if (jh->b_committed_data) {
375 struct buffer_head *bh = jh2bh(jh);
376
377 jbd_lock_bh_state(bh);
Badari Pulavartyea817392006-08-27 01:23:52 -0700378 jbd_slab_free(jh->b_committed_data, bh->b_size);
Jesper Juhlf99d49a2005-11-07 01:01:34 -0800379 jh->b_committed_data = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 jbd_unlock_bh_state(bh);
381 }
382 journal_refile_buffer(journal, jh);
383 }
384
385 /*
386 * Now try to drop any written-back buffers from the journal's
387 * checkpoint lists. We do this *before* commit because it potentially
388 * frees some memory
389 */
390 spin_lock(&journal->j_list_lock);
391 __journal_clean_checkpoint_list(journal);
392 spin_unlock(&journal->j_list_lock);
393
394 jbd_debug (3, "JBD: commit phase 1\n");
395
396 /*
397 * Switch to a new revoke table.
398 */
399 journal_switch_revoke_table(journal);
400
401 commit_transaction->t_state = T_FLUSH;
402 journal->j_committing_transaction = commit_transaction;
403 journal->j_running_transaction = NULL;
404 commit_transaction->t_log_start = journal->j_head;
405 wake_up(&journal->j_wait_transaction_locked);
406 spin_unlock(&journal->j_state_lock);
407
408 jbd_debug (3, "JBD: commit phase 2\n");
409
410 /*
411 * First, drop modified flag: all accesses to the buffers
412 * will be tracked for a new trasaction only -bzzz
413 */
414 spin_lock(&journal->j_list_lock);
415 if (commit_transaction->t_buffers) {
416 new_jh = jh = commit_transaction->t_buffers->b_tnext;
417 do {
418 J_ASSERT_JH(new_jh, new_jh->b_modified == 1 ||
419 new_jh->b_modified == 0);
420 new_jh->b_modified = 0;
421 new_jh = new_jh->b_tnext;
422 } while (new_jh != jh);
423 }
424 spin_unlock(&journal->j_list_lock);
425
426 /*
427 * Now start flushing things to disk, in the order they appear
428 * on the transaction lists. Data blocks go first.
429 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700430 err = 0;
Jan Kara3998b932006-09-25 23:30:53 -0700431 journal_submit_data_buffers(journal, commit_transaction);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432
433 /*
434 * Wait for all previously submitted IO to complete.
435 */
Jan Kara3998b932006-09-25 23:30:53 -0700436 spin_lock(&journal->j_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700437 while (commit_transaction->t_locked_list) {
438 struct buffer_head *bh;
439
440 jh = commit_transaction->t_locked_list->b_tprev;
441 bh = jh2bh(jh);
442 get_bh(bh);
443 if (buffer_locked(bh)) {
444 spin_unlock(&journal->j_list_lock);
445 wait_on_buffer(bh);
446 if (unlikely(!buffer_uptodate(bh)))
447 err = -EIO;
448 spin_lock(&journal->j_list_lock);
449 }
450 if (!inverted_lock(journal, bh)) {
451 put_bh(bh);
452 spin_lock(&journal->j_list_lock);
453 continue;
454 }
455 if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
456 __journal_unfile_buffer(jh);
457 jbd_unlock_bh_state(bh);
458 journal_remove_journal_head(bh);
459 put_bh(bh);
460 } else {
461 jbd_unlock_bh_state(bh);
462 }
463 put_bh(bh);
464 cond_resched_lock(&journal->j_list_lock);
465 }
466 spin_unlock(&journal->j_list_lock);
467
468 if (err)
469 __journal_abort_hard(journal);
470
471 journal_write_revoke_records(journal, commit_transaction);
472
473 jbd_debug(3, "JBD: commit phase 2\n");
474
475 /*
476 * If we found any dirty or locked buffers, then we should have
477 * looped back up to the write_out_data label. If there weren't
478 * any then journal_clean_data_list should have wiped the list
479 * clean by now, so check that it is in fact empty.
480 */
481 J_ASSERT (commit_transaction->t_sync_datalist == NULL);
482
483 jbd_debug (3, "JBD: commit phase 3\n");
484
485 /*
486 * Way to go: we have now written out all of the data for a
487 * transaction! Now comes the tricky part: we need to write out
488 * metadata. Loop over the transaction's entire buffer list:
489 */
490 commit_transaction->t_state = T_COMMIT;
491
492 descriptor = NULL;
493 bufs = 0;
494 while (commit_transaction->t_buffers) {
495
496 /* Find the next buffer to be journaled... */
497
498 jh = commit_transaction->t_buffers;
499
500 /* If we're in abort mode, we just un-journal the buffer and
501 release it for background writing. */
502
503 if (is_journal_aborted(journal)) {
504 JBUFFER_TRACE(jh, "journal is aborting: refile");
505 journal_refile_buffer(journal, jh);
506 /* If that was the last one, we need to clean up
507 * any descriptor buffers which may have been
508 * already allocated, even if we are now
509 * aborting. */
510 if (!commit_transaction->t_buffers)
511 goto start_journal_io;
512 continue;
513 }
514
515 /* Make sure we have a descriptor block in which to
516 record the metadata buffer. */
517
518 if (!descriptor) {
519 struct buffer_head *bh;
520
521 J_ASSERT (bufs == 0);
522
523 jbd_debug(4, "JBD: get descriptor\n");
524
525 descriptor = journal_get_descriptor_buffer(journal);
526 if (!descriptor) {
527 __journal_abort_hard(journal);
528 continue;
529 }
530
531 bh = jh2bh(descriptor);
532 jbd_debug(4, "JBD: got buffer %llu (%p)\n",
533 (unsigned long long)bh->b_blocknr, bh->b_data);
534 header = (journal_header_t *)&bh->b_data[0];
535 header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
536 header->h_blocktype = cpu_to_be32(JFS_DESCRIPTOR_BLOCK);
537 header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
538
539 tagp = &bh->b_data[sizeof(journal_header_t)];
540 space_left = bh->b_size - sizeof(journal_header_t);
541 first_tag = 1;
542 set_buffer_jwrite(bh);
543 set_buffer_dirty(bh);
544 wbuf[bufs++] = bh;
545
546 /* Record it so that we can wait for IO
547 completion later */
548 BUFFER_TRACE(bh, "ph3: file as descriptor");
549 journal_file_buffer(descriptor, commit_transaction,
550 BJ_LogCtl);
551 }
552
553 /* Where is the buffer to be written? */
554
555 err = journal_next_log_block(journal, &blocknr);
556 /* If the block mapping failed, just abandon the buffer
557 and repeat this loop: we'll fall into the
558 refile-on-abort condition above. */
559 if (err) {
560 __journal_abort_hard(journal);
561 continue;
562 }
563
564 /*
565 * start_this_handle() uses t_outstanding_credits to determine
566 * the free space in the log, but this counter is changed
567 * by journal_next_log_block() also.
568 */
569 commit_transaction->t_outstanding_credits--;
570
571 /* Bump b_count to prevent truncate from stumbling over
572 the shadowed buffer! @@@ This can go if we ever get
573 rid of the BJ_IO/BJ_Shadow pairing of buffers. */
574 atomic_inc(&jh2bh(jh)->b_count);
575
576 /* Make a temporary IO buffer with which to write it out
577 (this will requeue both the metadata buffer and the
578 temporary IO buffer). new_bh goes on BJ_IO*/
579
580 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
581 /*
582 * akpm: journal_write_metadata_buffer() sets
583 * new_bh->b_transaction to commit_transaction.
584 * We need to clean this up before we release new_bh
585 * (which is of type BJ_IO)
586 */
587 JBUFFER_TRACE(jh, "ph3: write metadata");
588 flags = journal_write_metadata_buffer(commit_transaction,
589 jh, &new_jh, blocknr);
590 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state);
591 wbuf[bufs++] = jh2bh(new_jh);
592
593 /* Record the new block's tag in the current descriptor
594 buffer */
595
596 tag_flag = 0;
597 if (flags & 1)
598 tag_flag |= JFS_FLAG_ESCAPE;
599 if (!first_tag)
600 tag_flag |= JFS_FLAG_SAME_UUID;
601
602 tag = (journal_block_tag_t *) tagp;
603 tag->t_blocknr = cpu_to_be32(jh2bh(jh)->b_blocknr);
604 tag->t_flags = cpu_to_be32(tag_flag);
605 tagp += sizeof(journal_block_tag_t);
606 space_left -= sizeof(journal_block_tag_t);
607
608 if (first_tag) {
609 memcpy (tagp, journal->j_uuid, 16);
610 tagp += 16;
611 space_left -= 16;
612 first_tag = 0;
613 }
614
615 /* If there's no more to do, or if the descriptor is full,
616 let the IO rip! */
617
618 if (bufs == journal->j_wbufsize ||
619 commit_transaction->t_buffers == NULL ||
620 space_left < sizeof(journal_block_tag_t) + 16) {
621
622 jbd_debug(4, "JBD: Submit %d IOs\n", bufs);
623
624 /* Write an end-of-descriptor marker before
625 submitting the IOs. "tag" still points to
626 the last tag we set up. */
627
628 tag->t_flags |= cpu_to_be32(JFS_FLAG_LAST_TAG);
629
630start_journal_io:
631 for (i = 0; i < bufs; i++) {
632 struct buffer_head *bh = wbuf[i];
633 lock_buffer(bh);
634 clear_buffer_dirty(bh);
635 set_buffer_uptodate(bh);
636 bh->b_end_io = journal_end_buffer_io_sync;
637 submit_bh(WRITE, bh);
638 }
639 cond_resched();
640
641 /* Force a new descriptor to be generated next
642 time round the loop. */
643 descriptor = NULL;
644 bufs = 0;
645 }
646 }
647
648 /* Lo and behold: we have just managed to send a transaction to
649 the log. Before we can commit it, wait for the IO so far to
650 complete. Control buffers being written are on the
651 transaction's t_log_list queue, and metadata buffers are on
652 the t_iobuf_list queue.
653
654 Wait for the buffers in reverse order. That way we are
655 less likely to be woken up until all IOs have completed, and
656 so we incur less scheduling load.
657 */
658
659 jbd_debug(3, "JBD: commit phase 4\n");
660
661 /*
662 * akpm: these are BJ_IO, and j_list_lock is not needed.
663 * See __journal_try_to_free_buffer.
664 */
665wait_for_iobuf:
666 while (commit_transaction->t_iobuf_list != NULL) {
667 struct buffer_head *bh;
668
669 jh = commit_transaction->t_iobuf_list->b_tprev;
670 bh = jh2bh(jh);
671 if (buffer_locked(bh)) {
672 wait_on_buffer(bh);
673 goto wait_for_iobuf;
674 }
675 if (cond_resched())
676 goto wait_for_iobuf;
677
678 if (unlikely(!buffer_uptodate(bh)))
679 err = -EIO;
680
681 clear_buffer_jwrite(bh);
682
683 JBUFFER_TRACE(jh, "ph4: unfile after journal write");
684 journal_unfile_buffer(journal, jh);
685
686 /*
687 * ->t_iobuf_list should contain only dummy buffer_heads
688 * which were created by journal_write_metadata_buffer().
689 */
690 BUFFER_TRACE(bh, "dumping temporary bh");
691 journal_put_journal_head(jh);
692 __brelse(bh);
693 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
694 free_buffer_head(bh);
695
696 /* We also have to unlock and free the corresponding
697 shadowed buffer */
698 jh = commit_transaction->t_shadow_list->b_tprev;
699 bh = jh2bh(jh);
700 clear_bit(BH_JWrite, &bh->b_state);
701 J_ASSERT_BH(bh, buffer_jbddirty(bh));
702
703 /* The metadata is now released for reuse, but we need
704 to remember it against this transaction so that when
705 we finally commit, we can do any checkpointing
706 required. */
707 JBUFFER_TRACE(jh, "file as BJ_Forget");
708 journal_file_buffer(jh, commit_transaction, BJ_Forget);
709 /* Wake up any transactions which were waiting for this
710 IO to complete */
711 wake_up_bit(&bh->b_state, BH_Unshadow);
712 JBUFFER_TRACE(jh, "brelse shadowed buffer");
713 __brelse(bh);
714 }
715
716 J_ASSERT (commit_transaction->t_shadow_list == NULL);
717
718 jbd_debug(3, "JBD: commit phase 5\n");
719
720 /* Here we wait for the revoke record and descriptor record buffers */
721 wait_for_ctlbuf:
722 while (commit_transaction->t_log_list != NULL) {
723 struct buffer_head *bh;
724
725 jh = commit_transaction->t_log_list->b_tprev;
726 bh = jh2bh(jh);
727 if (buffer_locked(bh)) {
728 wait_on_buffer(bh);
729 goto wait_for_ctlbuf;
730 }
731 if (cond_resched())
732 goto wait_for_ctlbuf;
733
734 if (unlikely(!buffer_uptodate(bh)))
735 err = -EIO;
736
737 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
738 clear_buffer_jwrite(bh);
739 journal_unfile_buffer(journal, jh);
740 journal_put_journal_head(jh);
741 __brelse(bh); /* One for getblk */
742 /* AKPM: bforget here */
743 }
744
745 jbd_debug(3, "JBD: commit phase 6\n");
746
747 if (journal_write_commit_record(journal, commit_transaction))
748 err = -EIO;
749
750 if (err)
751 __journal_abort_hard(journal);
752
753 /* End of a transaction! Finally, we can do checkpoint
754 processing: any buffers committed as a result of this
755 transaction can be removed from any checkpoint list it was on
756 before. */
757
758 jbd_debug(3, "JBD: commit phase 7\n");
759
760 J_ASSERT(commit_transaction->t_sync_datalist == NULL);
761 J_ASSERT(commit_transaction->t_buffers == NULL);
762 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
763 J_ASSERT(commit_transaction->t_iobuf_list == NULL);
764 J_ASSERT(commit_transaction->t_shadow_list == NULL);
765 J_ASSERT(commit_transaction->t_log_list == NULL);
766
767restart_loop:
Jan Karae6c9f5c2005-09-06 15:19:09 -0700768 /*
769 * As there are other places (journal_unmap_buffer()) adding buffers
770 * to this list we have to be careful and hold the j_list_lock.
771 */
772 spin_lock(&journal->j_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700773 while (commit_transaction->t_forget) {
774 transaction_t *cp_transaction;
775 struct buffer_head *bh;
776
777 jh = commit_transaction->t_forget;
Jan Karae6c9f5c2005-09-06 15:19:09 -0700778 spin_unlock(&journal->j_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779 bh = jh2bh(jh);
780 jbd_lock_bh_state(bh);
781 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction ||
782 jh->b_transaction == journal->j_running_transaction);
783
784 /*
785 * If there is undo-protected committed data against
786 * this buffer, then we can remove it now. If it is a
787 * buffer needing such protection, the old frozen_data
788 * field now points to a committed version of the
789 * buffer, so rotate that field to the new committed
790 * data.
791 *
792 * Otherwise, we can just throw away the frozen data now.
793 */
794 if (jh->b_committed_data) {
Badari Pulavartyea817392006-08-27 01:23:52 -0700795 jbd_slab_free(jh->b_committed_data, bh->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796 jh->b_committed_data = NULL;
797 if (jh->b_frozen_data) {
798 jh->b_committed_data = jh->b_frozen_data;
799 jh->b_frozen_data = NULL;
800 }
801 } else if (jh->b_frozen_data) {
Badari Pulavartyea817392006-08-27 01:23:52 -0700802 jbd_slab_free(jh->b_frozen_data, bh->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700803 jh->b_frozen_data = NULL;
804 }
805
806 spin_lock(&journal->j_list_lock);
807 cp_transaction = jh->b_cp_transaction;
808 if (cp_transaction) {
809 JBUFFER_TRACE(jh, "remove from old cp transaction");
810 __journal_remove_checkpoint(jh);
811 }
812
813 /* Only re-checkpoint the buffer_head if it is marked
814 * dirty. If the buffer was added to the BJ_Forget list
815 * by journal_forget, it may no longer be dirty and
816 * there's no point in keeping a checkpoint record for
817 * it. */
818
819 /* A buffer which has been freed while still being
820 * journaled by a previous transaction may end up still
821 * being dirty here, but we want to avoid writing back
822 * that buffer in the future now that the last use has
823 * been committed. That's not only a performance gain,
824 * it also stops aliasing problems if the buffer is left
825 * behind for writeback and gets reallocated for another
826 * use in a different page. */
827 if (buffer_freed(bh)) {
828 clear_buffer_freed(bh);
829 clear_buffer_jbddirty(bh);
830 }
831
832 if (buffer_jbddirty(bh)) {
833 JBUFFER_TRACE(jh, "add to new checkpointing trans");
834 __journal_insert_checkpoint(jh, commit_transaction);
835 JBUFFER_TRACE(jh, "refile for checkpoint writeback");
836 __journal_refile_buffer(jh);
837 jbd_unlock_bh_state(bh);
838 } else {
839 J_ASSERT_BH(bh, !buffer_dirty(bh));
Jan Kara9ada7342006-06-23 02:05:25 -0700840 /* The buffer on BJ_Forget list and not jbddirty means
841 * it has been freed by this transaction and hence it
842 * could not have been reallocated until this
843 * transaction has committed. *BUT* it could be
844 * reallocated once we have written all the data to
845 * disk and before we process the buffer on BJ_Forget
846 * list. */
847 JBUFFER_TRACE(jh, "refile or unfile freed buffer");
848 __journal_refile_buffer(jh);
849 if (!jh->b_transaction) {
850 jbd_unlock_bh_state(bh);
851 /* needs a brelse */
852 journal_remove_journal_head(bh);
853 release_buffer_page(bh);
854 } else
855 jbd_unlock_bh_state(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700856 }
Jan Karae6c9f5c2005-09-06 15:19:09 -0700857 cond_resched_lock(&journal->j_list_lock);
858 }
859 spin_unlock(&journal->j_list_lock);
860 /*
861 * This is a bit sleazy. We borrow j_list_lock to protect
862 * journal->j_committing_transaction in __journal_remove_checkpoint.
863 * Really, __journal_remove_checkpoint should be using j_state_lock but
864 * it's a bit hassle to hold that across __journal_remove_checkpoint
865 */
866 spin_lock(&journal->j_state_lock);
867 spin_lock(&journal->j_list_lock);
868 /*
869 * Now recheck if some buffers did not get attached to the transaction
870 * while the lock was dropped...
871 */
872 if (commit_transaction->t_forget) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700873 spin_unlock(&journal->j_list_lock);
Jan Karae6c9f5c2005-09-06 15:19:09 -0700874 spin_unlock(&journal->j_state_lock);
875 goto restart_loop;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 }
877
878 /* Done with this transaction! */
879
880 jbd_debug(3, "JBD: commit phase 8\n");
881
882 J_ASSERT(commit_transaction->t_state == T_COMMIT);
883
Linus Torvalds1da177e2005-04-16 15:20:36 -0700884 commit_transaction->t_state = T_FINISHED;
885 J_ASSERT(commit_transaction == journal->j_committing_transaction);
886 journal->j_commit_sequence = commit_transaction->t_tid;
887 journal->j_committing_transaction = NULL;
888 spin_unlock(&journal->j_state_lock);
889
Mark Fasheh7c8903f2006-02-14 13:53:03 -0800890 if (commit_transaction->t_checkpoint_list == NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891 __journal_drop_transaction(journal, commit_transaction);
892 } else {
893 if (journal->j_checkpoint_transactions == NULL) {
894 journal->j_checkpoint_transactions = commit_transaction;
895 commit_transaction->t_cpnext = commit_transaction;
896 commit_transaction->t_cpprev = commit_transaction;
897 } else {
898 commit_transaction->t_cpnext =
899 journal->j_checkpoint_transactions;
900 commit_transaction->t_cpprev =
901 commit_transaction->t_cpnext->t_cpprev;
902 commit_transaction->t_cpnext->t_cpprev =
903 commit_transaction;
904 commit_transaction->t_cpprev->t_cpnext =
905 commit_transaction;
906 }
907 }
908 spin_unlock(&journal->j_list_lock);
909
910 jbd_debug(1, "JBD: commit %d complete, head %d\n",
911 journal->j_commit_sequence, journal->j_tail_sequence);
912
913 wake_up(&journal->j_wait_done_commit);
914}