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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
Toshiyuki Okajimafc80c442008-07-25 01:46:29 -070039 * not successfully freed, because they are attached to a committing transaction.
Linus Torvalds1da177e2005-04-16 15:20:36 -070040 * 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 *
Toshiyuki Okajimafc80c442008-07-25 01:46:29 -070048 * Called under journal->j_list_lock. The caller provided us with a ref
49 * against the buffer, and we drop that here.
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 */
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 */
Nick Piggin529ae9a2008-08-02 12:01:03 +020066 if (!trylock_page(page))
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 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/*
Toshiyuki Okajimafc80c442008-07-25 01:46:29 -070081 * Decrement reference counter for data buffer. If it has been marked
82 * 'BH_Freed', release it and the page to which it belongs if possible.
83 */
84static void release_data_buffer(struct buffer_head *bh)
85{
86 if (buffer_freed(bh)) {
87 clear_buffer_freed(bh);
88 release_buffer_page(bh);
89 } else
90 put_bh(bh);
91}
92
93/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070094 * Try to acquire jbd_lock_bh_state() against the buffer, when j_list_lock is
95 * held. For ranking reasons we must trylock. If we lose, schedule away and
96 * return 0. j_list_lock is dropped in this case.
97 */
98static int inverted_lock(journal_t *journal, struct buffer_head *bh)
99{
100 if (!jbd_trylock_bh_state(bh)) {
101 spin_unlock(&journal->j_list_lock);
102 schedule();
103 return 0;
104 }
105 return 1;
106}
107
108/* Done it all: now write the commit record. We should have
109 * cleaned up our previous buffers by now, so if we are in abort
110 * mode we can now just skip the rest of the journal write
111 * entirely.
112 *
113 * Returns 1 if the journal needs to be aborted or 0 on success
114 */
115static int journal_write_commit_record(journal_t *journal,
116 transaction_t *commit_transaction)
117{
118 struct journal_head *descriptor;
119 struct buffer_head *bh;
Jan Kara53152172008-02-01 08:26:46 -0500120 journal_header_t *header;
121 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122 int barrier_done = 0;
123
124 if (is_journal_aborted(journal))
125 return 0;
126
127 descriptor = journal_get_descriptor_buffer(journal);
128 if (!descriptor)
129 return 1;
130
131 bh = jh2bh(descriptor);
132
Jan Kara53152172008-02-01 08:26:46 -0500133 header = (journal_header_t *)(bh->b_data);
134 header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
135 header->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK);
136 header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700137
138 JBUFFER_TRACE(descriptor, "write commit block");
139 set_buffer_dirty(bh);
140 if (journal->j_flags & JFS_BARRIER) {
141 set_buffer_ordered(bh);
142 barrier_done = 1;
143 }
144 ret = sync_dirty_buffer(bh);
Neil Brown28ae0942008-02-08 04:22:13 -0800145 if (barrier_done)
146 clear_buffer_ordered(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700147 /* is it possible for another commit to fail at roughly
148 * the same time as this one? If so, we don't want to
149 * trust the barrier flag in the super, but instead want
150 * to remember if we sent a barrier request
151 */
152 if (ret == -EOPNOTSUPP && barrier_done) {
153 char b[BDEVNAME_SIZE];
154
155 printk(KERN_WARNING
156 "JBD: barrier-based sync failed on %s - "
157 "disabling barriers\n",
158 bdevname(journal->j_dev, b));
159 spin_lock(&journal->j_state_lock);
160 journal->j_flags &= ~JFS_BARRIER;
161 spin_unlock(&journal->j_state_lock);
162
163 /* And try again, without the barrier */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 set_buffer_uptodate(bh);
165 set_buffer_dirty(bh);
166 ret = sync_dirty_buffer(bh);
167 }
168 put_bh(bh); /* One for getblk() */
169 journal_put_journal_head(descriptor);
170
171 return (ret == -EIO);
172}
173
Jan Kara3998b932006-09-25 23:30:53 -0700174static void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
175{
176 int i;
177
178 for (i = 0; i < bufs; i++) {
179 wbuf[i]->b_end_io = end_buffer_write_sync;
180 /* We use-up our safety reference in submit_bh() */
181 submit_bh(WRITE, wbuf[i]);
182 }
183}
184
185/*
186 * Submit all the data buffers to disk
187 */
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700188static int journal_submit_data_buffers(journal_t *journal,
Jan Kara3998b932006-09-25 23:30:53 -0700189 transaction_t *commit_transaction)
190{
191 struct journal_head *jh;
192 struct buffer_head *bh;
193 int locked;
194 int bufs = 0;
195 struct buffer_head **wbuf = journal->j_wbuf;
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700196 int err = 0;
Jan Kara3998b932006-09-25 23:30:53 -0700197
198 /*
199 * Whenever we unlock the journal and sleep, things can get added
200 * onto ->t_sync_datalist, so we have to keep looping back to
201 * write_out_data until we *know* that the list is empty.
202 *
203 * Cleanup any flushed data buffers from the data list. Even in
204 * abort mode, we want to flush this out as soon as possible.
205 */
206write_out_data:
207 cond_resched();
208 spin_lock(&journal->j_list_lock);
209
210 while (commit_transaction->t_sync_datalist) {
211 jh = commit_transaction->t_sync_datalist;
212 bh = jh2bh(jh);
213 locked = 0;
214
215 /* Get reference just to make sure buffer does not disappear
216 * when we are forced to drop various locks */
217 get_bh(bh);
218 /* If the buffer is dirty, we need to submit IO and hence
219 * we need the buffer lock. We try to lock the buffer without
220 * blocking. If we fail, we need to drop j_list_lock and do
221 * blocking lock_buffer().
222 */
223 if (buffer_dirty(bh)) {
Nick Pigginca5de402008-08-02 12:02:13 +0200224 if (!trylock_buffer(bh)) {
Jan Kara3998b932006-09-25 23:30:53 -0700225 BUFFER_TRACE(bh, "needs blocking lock");
226 spin_unlock(&journal->j_list_lock);
227 /* Write out all data to prevent deadlocks */
228 journal_do_submit_data(wbuf, bufs);
229 bufs = 0;
230 lock_buffer(bh);
231 spin_lock(&journal->j_list_lock);
232 }
233 locked = 1;
234 }
235 /* We have to get bh_state lock. Again out of order, sigh. */
236 if (!inverted_lock(journal, bh)) {
237 jbd_lock_bh_state(bh);
238 spin_lock(&journal->j_list_lock);
239 }
240 /* Someone already cleaned up the buffer? */
241 if (!buffer_jbd(bh)
242 || jh->b_transaction != commit_transaction
243 || jh->b_jlist != BJ_SyncData) {
244 jbd_unlock_bh_state(bh);
245 if (locked)
246 unlock_buffer(bh);
247 BUFFER_TRACE(bh, "already cleaned up");
Toshiyuki Okajimafc80c442008-07-25 01:46:29 -0700248 release_data_buffer(bh);
Jan Kara3998b932006-09-25 23:30:53 -0700249 continue;
250 }
251 if (locked && test_clear_buffer_dirty(bh)) {
252 BUFFER_TRACE(bh, "needs writeout, adding to array");
253 wbuf[bufs++] = bh;
254 __journal_file_buffer(jh, commit_transaction,
255 BJ_Locked);
256 jbd_unlock_bh_state(bh);
257 if (bufs == journal->j_wbufsize) {
258 spin_unlock(&journal->j_list_lock);
259 journal_do_submit_data(wbuf, bufs);
260 bufs = 0;
261 goto write_out_data;
262 }
Hisashi Hifumi6f5a9da2006-12-22 01:11:50 -0800263 } else if (!locked && buffer_locked(bh)) {
264 __journal_file_buffer(jh, commit_transaction,
265 BJ_Locked);
266 jbd_unlock_bh_state(bh);
267 put_bh(bh);
268 } else {
Jan Kara3998b932006-09-25 23:30:53 -0700269 BUFFER_TRACE(bh, "writeout complete: unfile");
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700270 if (unlikely(!buffer_uptodate(bh)))
271 err = -EIO;
Jan Kara3998b932006-09-25 23:30:53 -0700272 __journal_unfile_buffer(jh);
273 jbd_unlock_bh_state(bh);
274 if (locked)
275 unlock_buffer(bh);
276 journal_remove_journal_head(bh);
Toshiyuki Okajimafc80c442008-07-25 01:46:29 -0700277 /* One for our safety reference, other for
Jan Kara3998b932006-09-25 23:30:53 -0700278 * journal_remove_journal_head() */
279 put_bh(bh);
Toshiyuki Okajimafc80c442008-07-25 01:46:29 -0700280 release_data_buffer(bh);
Jan Kara3998b932006-09-25 23:30:53 -0700281 }
282
Nick Piggin95c354f2008-01-30 13:31:20 +0100283 if (need_resched() || spin_needbreak(&journal->j_list_lock)) {
Jan Kara3998b932006-09-25 23:30:53 -0700284 spin_unlock(&journal->j_list_lock);
285 goto write_out_data;
286 }
287 }
288 spin_unlock(&journal->j_list_lock);
289 journal_do_submit_data(wbuf, bufs);
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700290
291 return err;
Jan Kara3998b932006-09-25 23:30:53 -0700292}
293
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294/*
295 * journal_commit_transaction
296 *
297 * The primary function for committing a transaction to the log. This
298 * function is called by the journal thread to begin a complete commit.
299 */
300void journal_commit_transaction(journal_t *journal)
301{
302 transaction_t *commit_transaction;
303 struct journal_head *jh, *new_jh, *descriptor;
304 struct buffer_head **wbuf = journal->j_wbuf;
305 int bufs;
306 int flags;
307 int err;
308 unsigned long blocknr;
Josef Bacikf420d4d2009-01-07 18:07:24 -0800309 ktime_t start_time;
310 u64 commit_time;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700311 char *tagp = NULL;
312 journal_header_t *header;
313 journal_block_tag_t *tag = NULL;
314 int space_left = 0;
315 int first_tag = 0;
316 int tag_flag;
317 int i;
318
319 /*
320 * First job: lock down the current transaction and wait for
321 * all outstanding updates to complete.
322 */
323
324#ifdef COMMIT_STATS
325 spin_lock(&journal->j_list_lock);
326 summarise_journal_usage(journal);
327 spin_unlock(&journal->j_list_lock);
328#endif
329
330 /* Do we need to erase the effects of a prior journal_flush? */
331 if (journal->j_flags & JFS_FLUSHED) {
332 jbd_debug(3, "super block updated\n");
333 journal_update_superblock(journal, 1);
334 } else {
335 jbd_debug(3, "superblock not updated\n");
336 }
337
338 J_ASSERT(journal->j_running_transaction != NULL);
339 J_ASSERT(journal->j_committing_transaction == NULL);
340
341 commit_transaction = journal->j_running_transaction;
342 J_ASSERT(commit_transaction->t_state == T_RUNNING);
343
344 jbd_debug(1, "JBD: starting commit of transaction %d\n",
345 commit_transaction->t_tid);
346
347 spin_lock(&journal->j_state_lock);
348 commit_transaction->t_state = T_LOCKED;
349
350 spin_lock(&commit_transaction->t_handle_lock);
351 while (commit_transaction->t_updates) {
352 DEFINE_WAIT(wait);
353
354 prepare_to_wait(&journal->j_wait_updates, &wait,
355 TASK_UNINTERRUPTIBLE);
356 if (commit_transaction->t_updates) {
357 spin_unlock(&commit_transaction->t_handle_lock);
358 spin_unlock(&journal->j_state_lock);
359 schedule();
360 spin_lock(&journal->j_state_lock);
361 spin_lock(&commit_transaction->t_handle_lock);
362 }
363 finish_wait(&journal->j_wait_updates, &wait);
364 }
365 spin_unlock(&commit_transaction->t_handle_lock);
366
367 J_ASSERT (commit_transaction->t_outstanding_credits <=
368 journal->j_max_transaction_buffers);
369
370 /*
371 * First thing we are allowed to do is to discard any remaining
372 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
373 * that there are no such buffers: if a large filesystem
374 * operation like a truncate needs to split itself over multiple
375 * transactions, then it may try to do a journal_restart() while
376 * there are still BJ_Reserved buffers outstanding. These must
377 * be released cleanly from the current transaction.
378 *
379 * In this case, the filesystem must still reserve write access
380 * again before modifying the buffer in the new transaction, but
381 * we do not require it to remember exactly which old buffers it
382 * has reserved. This is consistent with the existing behaviour
383 * that multiple journal_get_write_access() calls to the same
384 * buffer are perfectly permissable.
385 */
386 while (commit_transaction->t_reserved_list) {
387 jh = commit_transaction->t_reserved_list;
388 JBUFFER_TRACE(jh, "reserved, unused: refile");
389 /*
390 * A journal_get_undo_access()+journal_release_buffer() may
391 * leave undo-committed data.
392 */
393 if (jh->b_committed_data) {
394 struct buffer_head *bh = jh2bh(jh);
395
396 jbd_lock_bh_state(bh);
Mingming Caoc089d492007-10-16 18:38:25 -0400397 jbd_free(jh->b_committed_data, bh->b_size);
Jesper Juhlf99d49a2005-11-07 01:01:34 -0800398 jh->b_committed_data = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700399 jbd_unlock_bh_state(bh);
400 }
401 journal_refile_buffer(journal, jh);
402 }
403
404 /*
405 * Now try to drop any written-back buffers from the journal's
406 * checkpoint lists. We do this *before* commit because it potentially
407 * frees some memory
408 */
409 spin_lock(&journal->j_list_lock);
410 __journal_clean_checkpoint_list(journal);
411 spin_unlock(&journal->j_list_lock);
412
413 jbd_debug (3, "JBD: commit phase 1\n");
414
415 /*
416 * Switch to a new revoke table.
417 */
418 journal_switch_revoke_table(journal);
419
420 commit_transaction->t_state = T_FLUSH;
421 journal->j_committing_transaction = commit_transaction;
422 journal->j_running_transaction = NULL;
Josef Bacikf420d4d2009-01-07 18:07:24 -0800423 start_time = ktime_get();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 commit_transaction->t_log_start = journal->j_head;
425 wake_up(&journal->j_wait_transaction_locked);
426 spin_unlock(&journal->j_state_lock);
427
428 jbd_debug (3, "JBD: commit phase 2\n");
429
430 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 * Now start flushing things to disk, in the order they appear
432 * on the transaction lists. Data blocks go first.
433 */
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700434 err = journal_submit_data_buffers(journal, commit_transaction);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700435
436 /*
437 * Wait for all previously submitted IO to complete.
438 */
Jan Kara3998b932006-09-25 23:30:53 -0700439 spin_lock(&journal->j_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700440 while (commit_transaction->t_locked_list) {
441 struct buffer_head *bh;
442
443 jh = commit_transaction->t_locked_list->b_tprev;
444 bh = jh2bh(jh);
445 get_bh(bh);
446 if (buffer_locked(bh)) {
447 spin_unlock(&journal->j_list_lock);
448 wait_on_buffer(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 spin_lock(&journal->j_list_lock);
450 }
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700451 if (unlikely(!buffer_uptodate(bh))) {
Nick Piggin529ae9a2008-08-02 12:01:03 +0200452 if (!trylock_page(bh->b_page)) {
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700453 spin_unlock(&journal->j_list_lock);
454 lock_page(bh->b_page);
455 spin_lock(&journal->j_list_lock);
456 }
457 if (bh->b_page->mapping)
458 set_bit(AS_EIO, &bh->b_page->mapping->flags);
459
460 unlock_page(bh->b_page);
461 SetPageError(bh->b_page);
462 err = -EIO;
463 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 if (!inverted_lock(journal, bh)) {
465 put_bh(bh);
466 spin_lock(&journal->j_list_lock);
467 continue;
468 }
469 if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
470 __journal_unfile_buffer(jh);
471 jbd_unlock_bh_state(bh);
472 journal_remove_journal_head(bh);
473 put_bh(bh);
474 } else {
475 jbd_unlock_bh_state(bh);
476 }
Toshiyuki Okajimafc80c442008-07-25 01:46:29 -0700477 release_data_buffer(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 cond_resched_lock(&journal->j_list_lock);
479 }
480 spin_unlock(&journal->j_list_lock);
481
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700482 if (err) {
483 char b[BDEVNAME_SIZE];
484
485 printk(KERN_WARNING
486 "JBD: Detected IO errors while flushing file data "
487 "on %s\n", bdevname(journal->j_fs_dev, b));
Hidehiro Kawai0e4fb5e2008-10-18 20:27:57 -0700488 if (journal->j_flags & JFS_ABORT_ON_SYNCDATA_ERR)
489 journal_abort(journal, err);
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700490 err = 0;
491 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492
493 journal_write_revoke_records(journal, commit_transaction);
494
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 /*
496 * If we found any dirty or locked buffers, then we should have
497 * looped back up to the write_out_data label. If there weren't
498 * any then journal_clean_data_list should have wiped the list
499 * clean by now, so check that it is in fact empty.
500 */
501 J_ASSERT (commit_transaction->t_sync_datalist == NULL);
502
503 jbd_debug (3, "JBD: commit phase 3\n");
504
505 /*
506 * Way to go: we have now written out all of the data for a
507 * transaction! Now comes the tricky part: we need to write out
508 * metadata. Loop over the transaction's entire buffer list:
509 */
Mingming Cao772279c2008-05-14 16:05:41 -0700510 spin_lock(&journal->j_state_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 commit_transaction->t_state = T_COMMIT;
Mingming Cao772279c2008-05-14 16:05:41 -0700512 spin_unlock(&journal->j_state_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513
Josef Bacik5b9a4992008-04-28 02:16:12 -0700514 J_ASSERT(commit_transaction->t_nr_buffers <=
515 commit_transaction->t_outstanding_credits);
516
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517 descriptor = NULL;
518 bufs = 0;
519 while (commit_transaction->t_buffers) {
520
521 /* Find the next buffer to be journaled... */
522
523 jh = commit_transaction->t_buffers;
524
525 /* If we're in abort mode, we just un-journal the buffer and
Hidehiro Kawai885e3532008-10-18 20:27:54 -0700526 release it. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527
528 if (is_journal_aborted(journal)) {
Hidehiro Kawai885e3532008-10-18 20:27:54 -0700529 clear_buffer_jbddirty(jh2bh(jh));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 JBUFFER_TRACE(jh, "journal is aborting: refile");
531 journal_refile_buffer(journal, jh);
532 /* If that was the last one, we need to clean up
533 * any descriptor buffers which may have been
534 * already allocated, even if we are now
535 * aborting. */
536 if (!commit_transaction->t_buffers)
537 goto start_journal_io;
538 continue;
539 }
540
541 /* Make sure we have a descriptor block in which to
542 record the metadata buffer. */
543
544 if (!descriptor) {
545 struct buffer_head *bh;
546
547 J_ASSERT (bufs == 0);
548
549 jbd_debug(4, "JBD: get descriptor\n");
550
551 descriptor = journal_get_descriptor_buffer(journal);
552 if (!descriptor) {
Jan Kara7a266e72007-10-18 23:39:22 -0700553 journal_abort(journal, -EIO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 continue;
555 }
556
557 bh = jh2bh(descriptor);
558 jbd_debug(4, "JBD: got buffer %llu (%p)\n",
559 (unsigned long long)bh->b_blocknr, bh->b_data);
560 header = (journal_header_t *)&bh->b_data[0];
561 header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
562 header->h_blocktype = cpu_to_be32(JFS_DESCRIPTOR_BLOCK);
563 header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
564
565 tagp = &bh->b_data[sizeof(journal_header_t)];
566 space_left = bh->b_size - sizeof(journal_header_t);
567 first_tag = 1;
568 set_buffer_jwrite(bh);
569 set_buffer_dirty(bh);
570 wbuf[bufs++] = bh;
571
572 /* Record it so that we can wait for IO
573 completion later */
574 BUFFER_TRACE(bh, "ph3: file as descriptor");
575 journal_file_buffer(descriptor, commit_transaction,
576 BJ_LogCtl);
577 }
578
579 /* Where is the buffer to be written? */
580
581 err = journal_next_log_block(journal, &blocknr);
582 /* If the block mapping failed, just abandon the buffer
583 and repeat this loop: we'll fall into the
584 refile-on-abort condition above. */
585 if (err) {
Jan Kara7a266e72007-10-18 23:39:22 -0700586 journal_abort(journal, err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587 continue;
588 }
589
590 /*
591 * start_this_handle() uses t_outstanding_credits to determine
592 * the free space in the log, but this counter is changed
593 * by journal_next_log_block() also.
594 */
595 commit_transaction->t_outstanding_credits--;
596
597 /* Bump b_count to prevent truncate from stumbling over
598 the shadowed buffer! @@@ This can go if we ever get
599 rid of the BJ_IO/BJ_Shadow pairing of buffers. */
600 atomic_inc(&jh2bh(jh)->b_count);
601
602 /* Make a temporary IO buffer with which to write it out
603 (this will requeue both the metadata buffer and the
604 temporary IO buffer). new_bh goes on BJ_IO*/
605
606 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
607 /*
608 * akpm: journal_write_metadata_buffer() sets
609 * new_bh->b_transaction to commit_transaction.
610 * We need to clean this up before we release new_bh
611 * (which is of type BJ_IO)
612 */
613 JBUFFER_TRACE(jh, "ph3: write metadata");
614 flags = journal_write_metadata_buffer(commit_transaction,
615 jh, &new_jh, blocknr);
616 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state);
617 wbuf[bufs++] = jh2bh(new_jh);
618
619 /* Record the new block's tag in the current descriptor
620 buffer */
621
622 tag_flag = 0;
623 if (flags & 1)
624 tag_flag |= JFS_FLAG_ESCAPE;
625 if (!first_tag)
626 tag_flag |= JFS_FLAG_SAME_UUID;
627
628 tag = (journal_block_tag_t *) tagp;
629 tag->t_blocknr = cpu_to_be32(jh2bh(jh)->b_blocknr);
630 tag->t_flags = cpu_to_be32(tag_flag);
631 tagp += sizeof(journal_block_tag_t);
632 space_left -= sizeof(journal_block_tag_t);
633
634 if (first_tag) {
635 memcpy (tagp, journal->j_uuid, 16);
636 tagp += 16;
637 space_left -= 16;
638 first_tag = 0;
639 }
640
641 /* If there's no more to do, or if the descriptor is full,
642 let the IO rip! */
643
644 if (bufs == journal->j_wbufsize ||
645 commit_transaction->t_buffers == NULL ||
646 space_left < sizeof(journal_block_tag_t) + 16) {
647
648 jbd_debug(4, "JBD: Submit %d IOs\n", bufs);
649
650 /* Write an end-of-descriptor marker before
651 submitting the IOs. "tag" still points to
652 the last tag we set up. */
653
654 tag->t_flags |= cpu_to_be32(JFS_FLAG_LAST_TAG);
655
656start_journal_io:
657 for (i = 0; i < bufs; i++) {
658 struct buffer_head *bh = wbuf[i];
659 lock_buffer(bh);
660 clear_buffer_dirty(bh);
661 set_buffer_uptodate(bh);
662 bh->b_end_io = journal_end_buffer_io_sync;
663 submit_bh(WRITE, bh);
664 }
665 cond_resched();
666
667 /* Force a new descriptor to be generated next
668 time round the loop. */
669 descriptor = NULL;
670 bufs = 0;
671 }
672 }
673
674 /* Lo and behold: we have just managed to send a transaction to
675 the log. Before we can commit it, wait for the IO so far to
676 complete. Control buffers being written are on the
677 transaction's t_log_list queue, and metadata buffers are on
678 the t_iobuf_list queue.
679
680 Wait for the buffers in reverse order. That way we are
681 less likely to be woken up until all IOs have completed, and
682 so we incur less scheduling load.
683 */
684
685 jbd_debug(3, "JBD: commit phase 4\n");
686
687 /*
688 * akpm: these are BJ_IO, and j_list_lock is not needed.
689 * See __journal_try_to_free_buffer.
690 */
691wait_for_iobuf:
692 while (commit_transaction->t_iobuf_list != NULL) {
693 struct buffer_head *bh;
694
695 jh = commit_transaction->t_iobuf_list->b_tprev;
696 bh = jh2bh(jh);
697 if (buffer_locked(bh)) {
698 wait_on_buffer(bh);
699 goto wait_for_iobuf;
700 }
701 if (cond_resched())
702 goto wait_for_iobuf;
703
704 if (unlikely(!buffer_uptodate(bh)))
705 err = -EIO;
706
707 clear_buffer_jwrite(bh);
708
709 JBUFFER_TRACE(jh, "ph4: unfile after journal write");
710 journal_unfile_buffer(journal, jh);
711
712 /*
713 * ->t_iobuf_list should contain only dummy buffer_heads
714 * which were created by journal_write_metadata_buffer().
715 */
716 BUFFER_TRACE(bh, "dumping temporary bh");
717 journal_put_journal_head(jh);
718 __brelse(bh);
719 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
720 free_buffer_head(bh);
721
722 /* We also have to unlock and free the corresponding
723 shadowed buffer */
724 jh = commit_transaction->t_shadow_list->b_tprev;
725 bh = jh2bh(jh);
726 clear_bit(BH_JWrite, &bh->b_state);
727 J_ASSERT_BH(bh, buffer_jbddirty(bh));
728
729 /* The metadata is now released for reuse, but we need
730 to remember it against this transaction so that when
731 we finally commit, we can do any checkpointing
732 required. */
733 JBUFFER_TRACE(jh, "file as BJ_Forget");
734 journal_file_buffer(jh, commit_transaction, BJ_Forget);
735 /* Wake up any transactions which were waiting for this
736 IO to complete */
737 wake_up_bit(&bh->b_state, BH_Unshadow);
738 JBUFFER_TRACE(jh, "brelse shadowed buffer");
739 __brelse(bh);
740 }
741
742 J_ASSERT (commit_transaction->t_shadow_list == NULL);
743
744 jbd_debug(3, "JBD: commit phase 5\n");
745
746 /* Here we wait for the revoke record and descriptor record buffers */
747 wait_for_ctlbuf:
748 while (commit_transaction->t_log_list != NULL) {
749 struct buffer_head *bh;
750
751 jh = commit_transaction->t_log_list->b_tprev;
752 bh = jh2bh(jh);
753 if (buffer_locked(bh)) {
754 wait_on_buffer(bh);
755 goto wait_for_ctlbuf;
756 }
757 if (cond_resched())
758 goto wait_for_ctlbuf;
759
760 if (unlikely(!buffer_uptodate(bh)))
761 err = -EIO;
762
763 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
764 clear_buffer_jwrite(bh);
765 journal_unfile_buffer(journal, jh);
766 journal_put_journal_head(jh);
767 __brelse(bh); /* One for getblk */
768 /* AKPM: bforget here */
769 }
770
Hidehiro Kawaid1645e52008-10-18 20:27:53 -0700771 if (err)
772 journal_abort(journal, err);
773
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 jbd_debug(3, "JBD: commit phase 6\n");
775
776 if (journal_write_commit_record(journal, commit_transaction))
777 err = -EIO;
778
779 if (err)
Jan Kara7a266e72007-10-18 23:39:22 -0700780 journal_abort(journal, err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781
782 /* End of a transaction! Finally, we can do checkpoint
783 processing: any buffers committed as a result of this
784 transaction can be removed from any checkpoint list it was on
785 before. */
786
787 jbd_debug(3, "JBD: commit phase 7\n");
788
789 J_ASSERT(commit_transaction->t_sync_datalist == NULL);
790 J_ASSERT(commit_transaction->t_buffers == NULL);
791 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
792 J_ASSERT(commit_transaction->t_iobuf_list == NULL);
793 J_ASSERT(commit_transaction->t_shadow_list == NULL);
794 J_ASSERT(commit_transaction->t_log_list == NULL);
795
796restart_loop:
Jan Karae6c9f5c2005-09-06 15:19:09 -0700797 /*
798 * As there are other places (journal_unmap_buffer()) adding buffers
799 * to this list we have to be careful and hold the j_list_lock.
800 */
801 spin_lock(&journal->j_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700802 while (commit_transaction->t_forget) {
803 transaction_t *cp_transaction;
804 struct buffer_head *bh;
805
806 jh = commit_transaction->t_forget;
Jan Karae6c9f5c2005-09-06 15:19:09 -0700807 spin_unlock(&journal->j_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700808 bh = jh2bh(jh);
809 jbd_lock_bh_state(bh);
810 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction ||
811 jh->b_transaction == journal->j_running_transaction);
812
813 /*
814 * If there is undo-protected committed data against
815 * this buffer, then we can remove it now. If it is a
816 * buffer needing such protection, the old frozen_data
817 * field now points to a committed version of the
818 * buffer, so rotate that field to the new committed
819 * data.
820 *
821 * Otherwise, we can just throw away the frozen data now.
822 */
823 if (jh->b_committed_data) {
Mingming Caoc089d492007-10-16 18:38:25 -0400824 jbd_free(jh->b_committed_data, bh->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825 jh->b_committed_data = NULL;
826 if (jh->b_frozen_data) {
827 jh->b_committed_data = jh->b_frozen_data;
828 jh->b_frozen_data = NULL;
829 }
830 } else if (jh->b_frozen_data) {
Mingming Caoc089d492007-10-16 18:38:25 -0400831 jbd_free(jh->b_frozen_data, bh->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 jh->b_frozen_data = NULL;
833 }
834
835 spin_lock(&journal->j_list_lock);
836 cp_transaction = jh->b_cp_transaction;
837 if (cp_transaction) {
838 JBUFFER_TRACE(jh, "remove from old cp transaction");
839 __journal_remove_checkpoint(jh);
840 }
841
842 /* Only re-checkpoint the buffer_head if it is marked
843 * dirty. If the buffer was added to the BJ_Forget list
844 * by journal_forget, it may no longer be dirty and
845 * there's no point in keeping a checkpoint record for
846 * it. */
847
848 /* A buffer which has been freed while still being
849 * journaled by a previous transaction may end up still
850 * being dirty here, but we want to avoid writing back
851 * that buffer in the future now that the last use has
852 * been committed. That's not only a performance gain,
853 * it also stops aliasing problems if the buffer is left
854 * behind for writeback and gets reallocated for another
855 * use in a different page. */
856 if (buffer_freed(bh)) {
857 clear_buffer_freed(bh);
858 clear_buffer_jbddirty(bh);
859 }
860
861 if (buffer_jbddirty(bh)) {
862 JBUFFER_TRACE(jh, "add to new checkpointing trans");
863 __journal_insert_checkpoint(jh, commit_transaction);
Hidehiro Kawai885e3532008-10-18 20:27:54 -0700864 if (is_journal_aborted(journal))
865 clear_buffer_jbddirty(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700866 JBUFFER_TRACE(jh, "refile for checkpoint writeback");
867 __journal_refile_buffer(jh);
868 jbd_unlock_bh_state(bh);
869 } else {
870 J_ASSERT_BH(bh, !buffer_dirty(bh));
Jan Kara9ada7342006-06-23 02:05:25 -0700871 /* The buffer on BJ_Forget list and not jbddirty means
872 * it has been freed by this transaction and hence it
873 * could not have been reallocated until this
874 * transaction has committed. *BUT* it could be
875 * reallocated once we have written all the data to
876 * disk and before we process the buffer on BJ_Forget
877 * list. */
878 JBUFFER_TRACE(jh, "refile or unfile freed buffer");
879 __journal_refile_buffer(jh);
880 if (!jh->b_transaction) {
881 jbd_unlock_bh_state(bh);
882 /* needs a brelse */
883 journal_remove_journal_head(bh);
884 release_buffer_page(bh);
885 } else
886 jbd_unlock_bh_state(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700887 }
Jan Karae6c9f5c2005-09-06 15:19:09 -0700888 cond_resched_lock(&journal->j_list_lock);
889 }
890 spin_unlock(&journal->j_list_lock);
891 /*
Jan Karad4beaf42007-12-04 23:45:27 -0800892 * This is a bit sleazy. We use j_list_lock to protect transition
893 * of a transaction into T_FINISHED state and calling
894 * __journal_drop_transaction(). Otherwise we could race with
895 * other checkpointing code processing the transaction...
Jan Karae6c9f5c2005-09-06 15:19:09 -0700896 */
897 spin_lock(&journal->j_state_lock);
898 spin_lock(&journal->j_list_lock);
899 /*
900 * Now recheck if some buffers did not get attached to the transaction
901 * while the lock was dropped...
902 */
903 if (commit_transaction->t_forget) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700904 spin_unlock(&journal->j_list_lock);
Jan Karae6c9f5c2005-09-06 15:19:09 -0700905 spin_unlock(&journal->j_state_lock);
906 goto restart_loop;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907 }
908
909 /* Done with this transaction! */
910
911 jbd_debug(3, "JBD: commit phase 8\n");
912
913 J_ASSERT(commit_transaction->t_state == T_COMMIT);
914
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915 commit_transaction->t_state = T_FINISHED;
916 J_ASSERT(commit_transaction == journal->j_committing_transaction);
917 journal->j_commit_sequence = commit_transaction->t_tid;
918 journal->j_committing_transaction = NULL;
Josef Bacikf420d4d2009-01-07 18:07:24 -0800919 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
920
921 /*
922 * weight the commit time higher than the average time so we don't
923 * react too strongly to vast changes in commit time
924 */
925 if (likely(journal->j_average_commit_time))
926 journal->j_average_commit_time = (commit_time*3 +
927 journal->j_average_commit_time) / 4;
928 else
929 journal->j_average_commit_time = commit_time;
930
Linus Torvalds1da177e2005-04-16 15:20:36 -0700931 spin_unlock(&journal->j_state_lock);
932
Jan Karafe28e422007-07-15 23:37:18 -0700933 if (commit_transaction->t_checkpoint_list == NULL &&
934 commit_transaction->t_checkpoint_io_list == NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 __journal_drop_transaction(journal, commit_transaction);
936 } else {
937 if (journal->j_checkpoint_transactions == NULL) {
938 journal->j_checkpoint_transactions = commit_transaction;
939 commit_transaction->t_cpnext = commit_transaction;
940 commit_transaction->t_cpprev = commit_transaction;
941 } else {
942 commit_transaction->t_cpnext =
943 journal->j_checkpoint_transactions;
944 commit_transaction->t_cpprev =
945 commit_transaction->t_cpnext->t_cpprev;
946 commit_transaction->t_cpnext->t_cpprev =
947 commit_transaction;
948 commit_transaction->t_cpprev->t_cpnext =
949 commit_transaction;
950 }
951 }
952 spin_unlock(&journal->j_list_lock);
953
954 jbd_debug(1, "JBD: commit %d complete, head %d\n",
955 journal->j_commit_sequence, journal->j_tail_sequence);
956
957 wake_up(&journal->j_wait_done_commit);
958}