blob: 28a9ddaa0c496f85625ccab2d543fc5e0886872b [file] [log] [blame]
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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070020#include <linux/mm.h>
21#include <linux/pagemap.h>
Theodore Ts'o512a0042009-03-27 22:14:27 -040022#include <linux/bio.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
Theodore Ts'o512a0042009-03-27 22:14:27 -0400174static void journal_do_submit_data(struct buffer_head **wbuf, int bufs,
175 int write_op)
Jan Kara3998b932006-09-25 23:30:53 -0700176{
177 int i;
178
179 for (i = 0; i < bufs; i++) {
180 wbuf[i]->b_end_io = end_buffer_write_sync;
181 /* We use-up our safety reference in submit_bh() */
Theodore Ts'o512a0042009-03-27 22:14:27 -0400182 submit_bh(write_op, wbuf[i]);
Jan Kara3998b932006-09-25 23:30:53 -0700183 }
184}
185
186/*
187 * Submit all the data buffers to disk
188 */
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700189static int journal_submit_data_buffers(journal_t *journal,
Theodore Ts'o512a0042009-03-27 22:14:27 -0400190 transaction_t *commit_transaction,
191 int write_op)
Jan Kara3998b932006-09-25 23:30:53 -0700192{
193 struct journal_head *jh;
194 struct buffer_head *bh;
195 int locked;
196 int bufs = 0;
197 struct buffer_head **wbuf = journal->j_wbuf;
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700198 int err = 0;
Jan Kara3998b932006-09-25 23:30:53 -0700199
200 /*
201 * Whenever we unlock the journal and sleep, things can get added
202 * onto ->t_sync_datalist, so we have to keep looping back to
203 * write_out_data until we *know* that the list is empty.
204 *
205 * Cleanup any flushed data buffers from the data list. Even in
206 * abort mode, we want to flush this out as soon as possible.
207 */
208write_out_data:
209 cond_resched();
210 spin_lock(&journal->j_list_lock);
211
212 while (commit_transaction->t_sync_datalist) {
213 jh = commit_transaction->t_sync_datalist;
214 bh = jh2bh(jh);
215 locked = 0;
216
217 /* Get reference just to make sure buffer does not disappear
218 * when we are forced to drop various locks */
219 get_bh(bh);
220 /* If the buffer is dirty, we need to submit IO and hence
221 * we need the buffer lock. We try to lock the buffer without
222 * blocking. If we fail, we need to drop j_list_lock and do
223 * blocking lock_buffer().
224 */
225 if (buffer_dirty(bh)) {
Nick Pigginca5de402008-08-02 12:02:13 +0200226 if (!trylock_buffer(bh)) {
Jan Kara3998b932006-09-25 23:30:53 -0700227 BUFFER_TRACE(bh, "needs blocking lock");
228 spin_unlock(&journal->j_list_lock);
229 /* Write out all data to prevent deadlocks */
Theodore Ts'o512a0042009-03-27 22:14:27 -0400230 journal_do_submit_data(wbuf, bufs, write_op);
Jan Kara3998b932006-09-25 23:30:53 -0700231 bufs = 0;
232 lock_buffer(bh);
233 spin_lock(&journal->j_list_lock);
234 }
235 locked = 1;
236 }
237 /* We have to get bh_state lock. Again out of order, sigh. */
238 if (!inverted_lock(journal, bh)) {
239 jbd_lock_bh_state(bh);
240 spin_lock(&journal->j_list_lock);
241 }
242 /* Someone already cleaned up the buffer? */
Jan Karaa61d90d2009-06-09 16:26:26 -0700243 if (!buffer_jbd(bh) || bh2jh(bh) != jh
Jan Kara3998b932006-09-25 23:30:53 -0700244 || jh->b_transaction != commit_transaction
245 || jh->b_jlist != BJ_SyncData) {
246 jbd_unlock_bh_state(bh);
247 if (locked)
248 unlock_buffer(bh);
249 BUFFER_TRACE(bh, "already cleaned up");
Toshiyuki Okajimafc80c442008-07-25 01:46:29 -0700250 release_data_buffer(bh);
Jan Kara3998b932006-09-25 23:30:53 -0700251 continue;
252 }
253 if (locked && test_clear_buffer_dirty(bh)) {
254 BUFFER_TRACE(bh, "needs writeout, adding to array");
255 wbuf[bufs++] = bh;
256 __journal_file_buffer(jh, commit_transaction,
257 BJ_Locked);
258 jbd_unlock_bh_state(bh);
259 if (bufs == journal->j_wbufsize) {
260 spin_unlock(&journal->j_list_lock);
Theodore Ts'o512a0042009-03-27 22:14:27 -0400261 journal_do_submit_data(wbuf, bufs, write_op);
Jan Kara3998b932006-09-25 23:30:53 -0700262 bufs = 0;
263 goto write_out_data;
264 }
Hisashi Hifumi6f5a9da2006-12-22 01:11:50 -0800265 } else if (!locked && buffer_locked(bh)) {
266 __journal_file_buffer(jh, commit_transaction,
267 BJ_Locked);
268 jbd_unlock_bh_state(bh);
269 put_bh(bh);
270 } else {
Jan Kara3998b932006-09-25 23:30:53 -0700271 BUFFER_TRACE(bh, "writeout complete: unfile");
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700272 if (unlikely(!buffer_uptodate(bh)))
273 err = -EIO;
Jan Kara3998b932006-09-25 23:30:53 -0700274 __journal_unfile_buffer(jh);
275 jbd_unlock_bh_state(bh);
276 if (locked)
277 unlock_buffer(bh);
278 journal_remove_journal_head(bh);
Toshiyuki Okajimafc80c442008-07-25 01:46:29 -0700279 /* One for our safety reference, other for
Jan Kara3998b932006-09-25 23:30:53 -0700280 * journal_remove_journal_head() */
281 put_bh(bh);
Toshiyuki Okajimafc80c442008-07-25 01:46:29 -0700282 release_data_buffer(bh);
Jan Kara3998b932006-09-25 23:30:53 -0700283 }
284
Nick Piggin95c354f2008-01-30 13:31:20 +0100285 if (need_resched() || spin_needbreak(&journal->j_list_lock)) {
Jan Kara3998b932006-09-25 23:30:53 -0700286 spin_unlock(&journal->j_list_lock);
287 goto write_out_data;
288 }
289 }
290 spin_unlock(&journal->j_list_lock);
Theodore Ts'o512a0042009-03-27 22:14:27 -0400291 journal_do_submit_data(wbuf, bufs, write_op);
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700292
293 return err;
Jan Kara3998b932006-09-25 23:30:53 -0700294}
295
Linus Torvalds1da177e2005-04-16 15:20:36 -0700296/*
297 * journal_commit_transaction
298 *
299 * The primary function for committing a transaction to the log. This
300 * function is called by the journal thread to begin a complete commit.
301 */
302void journal_commit_transaction(journal_t *journal)
303{
304 transaction_t *commit_transaction;
305 struct journal_head *jh, *new_jh, *descriptor;
306 struct buffer_head **wbuf = journal->j_wbuf;
307 int bufs;
308 int flags;
309 int err;
Jan Kara9c28cbc2009-08-03 19:21:00 +0200310 unsigned int blocknr;
Josef Bacikf420d4d2009-01-07 18:07:24 -0800311 ktime_t start_time;
312 u64 commit_time;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700313 char *tagp = NULL;
314 journal_header_t *header;
315 journal_block_tag_t *tag = NULL;
316 int space_left = 0;
317 int first_tag = 0;
318 int tag_flag;
319 int i;
Theodore Ts'o512a0042009-03-27 22:14:27 -0400320 int write_op = WRITE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321
322 /*
323 * First job: lock down the current transaction and wait for
324 * all outstanding updates to complete.
325 */
326
327#ifdef COMMIT_STATS
328 spin_lock(&journal->j_list_lock);
329 summarise_journal_usage(journal);
330 spin_unlock(&journal->j_list_lock);
331#endif
332
333 /* Do we need to erase the effects of a prior journal_flush? */
334 if (journal->j_flags & JFS_FLUSHED) {
335 jbd_debug(3, "super block updated\n");
336 journal_update_superblock(journal, 1);
337 } else {
338 jbd_debug(3, "superblock not updated\n");
339 }
340
341 J_ASSERT(journal->j_running_transaction != NULL);
342 J_ASSERT(journal->j_committing_transaction == NULL);
343
344 commit_transaction = journal->j_running_transaction;
345 J_ASSERT(commit_transaction->t_state == T_RUNNING);
346
347 jbd_debug(1, "JBD: starting commit of transaction %d\n",
348 commit_transaction->t_tid);
349
350 spin_lock(&journal->j_state_lock);
351 commit_transaction->t_state = T_LOCKED;
352
Jens Axboe6c4bac62009-04-06 14:48:04 +0200353 /*
354 * Use plugged writes here, since we want to submit several before
355 * we unplug the device. We don't do explicit unplugging in here,
356 * instead we rely on sync_buffer() doing the unplug for us.
357 */
Theodore Ts'o512a0042009-03-27 22:14:27 -0400358 if (commit_transaction->t_synchronous_commit)
Jens Axboe6c4bac62009-04-06 14:48:04 +0200359 write_op = WRITE_SYNC_PLUG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 spin_lock(&commit_transaction->t_handle_lock);
361 while (commit_transaction->t_updates) {
362 DEFINE_WAIT(wait);
363
364 prepare_to_wait(&journal->j_wait_updates, &wait,
365 TASK_UNINTERRUPTIBLE);
366 if (commit_transaction->t_updates) {
367 spin_unlock(&commit_transaction->t_handle_lock);
368 spin_unlock(&journal->j_state_lock);
369 schedule();
370 spin_lock(&journal->j_state_lock);
371 spin_lock(&commit_transaction->t_handle_lock);
372 }
373 finish_wait(&journal->j_wait_updates, &wait);
374 }
375 spin_unlock(&commit_transaction->t_handle_lock);
376
377 J_ASSERT (commit_transaction->t_outstanding_credits <=
378 journal->j_max_transaction_buffers);
379
380 /*
381 * First thing we are allowed to do is to discard any remaining
382 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
383 * that there are no such buffers: if a large filesystem
384 * operation like a truncate needs to split itself over multiple
385 * transactions, then it may try to do a journal_restart() while
386 * there are still BJ_Reserved buffers outstanding. These must
387 * be released cleanly from the current transaction.
388 *
389 * In this case, the filesystem must still reserve write access
390 * again before modifying the buffer in the new transaction, but
391 * we do not require it to remember exactly which old buffers it
392 * has reserved. This is consistent with the existing behaviour
393 * that multiple journal_get_write_access() calls to the same
394 * buffer are perfectly permissable.
395 */
396 while (commit_transaction->t_reserved_list) {
397 jh = commit_transaction->t_reserved_list;
398 JBUFFER_TRACE(jh, "reserved, unused: refile");
399 /*
400 * A journal_get_undo_access()+journal_release_buffer() may
401 * leave undo-committed data.
402 */
403 if (jh->b_committed_data) {
404 struct buffer_head *bh = jh2bh(jh);
405
406 jbd_lock_bh_state(bh);
Mingming Caoc089d492007-10-16 18:38:25 -0400407 jbd_free(jh->b_committed_data, bh->b_size);
Jesper Juhlf99d49a2005-11-07 01:01:34 -0800408 jh->b_committed_data = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409 jbd_unlock_bh_state(bh);
410 }
411 journal_refile_buffer(journal, jh);
412 }
413
414 /*
415 * Now try to drop any written-back buffers from the journal's
416 * checkpoint lists. We do this *before* commit because it potentially
417 * frees some memory
418 */
419 spin_lock(&journal->j_list_lock);
420 __journal_clean_checkpoint_list(journal);
421 spin_unlock(&journal->j_list_lock);
422
423 jbd_debug (3, "JBD: commit phase 1\n");
424
425 /*
426 * Switch to a new revoke table.
427 */
428 journal_switch_revoke_table(journal);
429
430 commit_transaction->t_state = T_FLUSH;
431 journal->j_committing_transaction = commit_transaction;
432 journal->j_running_transaction = NULL;
Josef Bacikf420d4d2009-01-07 18:07:24 -0800433 start_time = ktime_get();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434 commit_transaction->t_log_start = journal->j_head;
435 wake_up(&journal->j_wait_transaction_locked);
436 spin_unlock(&journal->j_state_lock);
437
438 jbd_debug (3, "JBD: commit phase 2\n");
439
440 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 * Now start flushing things to disk, in the order they appear
442 * on the transaction lists. Data blocks go first.
443 */
Theodore Ts'o512a0042009-03-27 22:14:27 -0400444 err = journal_submit_data_buffers(journal, commit_transaction,
445 write_op);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446
447 /*
448 * Wait for all previously submitted IO to complete.
449 */
Jan Kara3998b932006-09-25 23:30:53 -0700450 spin_lock(&journal->j_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700451 while (commit_transaction->t_locked_list) {
452 struct buffer_head *bh;
453
454 jh = commit_transaction->t_locked_list->b_tprev;
455 bh = jh2bh(jh);
456 get_bh(bh);
457 if (buffer_locked(bh)) {
458 spin_unlock(&journal->j_list_lock);
459 wait_on_buffer(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460 spin_lock(&journal->j_list_lock);
461 }
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700462 if (unlikely(!buffer_uptodate(bh))) {
Nick Piggin529ae9a2008-08-02 12:01:03 +0200463 if (!trylock_page(bh->b_page)) {
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700464 spin_unlock(&journal->j_list_lock);
465 lock_page(bh->b_page);
466 spin_lock(&journal->j_list_lock);
467 }
468 if (bh->b_page->mapping)
469 set_bit(AS_EIO, &bh->b_page->mapping->flags);
470
471 unlock_page(bh->b_page);
472 SetPageError(bh->b_page);
473 err = -EIO;
474 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475 if (!inverted_lock(journal, bh)) {
476 put_bh(bh);
477 spin_lock(&journal->j_list_lock);
478 continue;
479 }
Jan Karaa61d90d2009-06-09 16:26:26 -0700480 if (buffer_jbd(bh) && bh2jh(bh) == jh &&
481 jh->b_transaction == commit_transaction &&
482 jh->b_jlist == BJ_Locked) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 __journal_unfile_buffer(jh);
484 jbd_unlock_bh_state(bh);
485 journal_remove_journal_head(bh);
486 put_bh(bh);
487 } else {
488 jbd_unlock_bh_state(bh);
489 }
Toshiyuki Okajimafc80c442008-07-25 01:46:29 -0700490 release_data_buffer(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 cond_resched_lock(&journal->j_list_lock);
492 }
493 spin_unlock(&journal->j_list_lock);
494
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700495 if (err) {
496 char b[BDEVNAME_SIZE];
497
498 printk(KERN_WARNING
499 "JBD: Detected IO errors while flushing file data "
500 "on %s\n", bdevname(journal->j_fs_dev, b));
Hidehiro Kawai0e4fb5e2008-10-18 20:27:57 -0700501 if (journal->j_flags & JFS_ABORT_ON_SYNCDATA_ERR)
502 journal_abort(journal, err);
Hidehiro Kawaicbe5f462008-07-25 01:46:30 -0700503 err = 0;
504 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505
Theodore Ts'o38d726d2009-04-14 10:10:47 -0400506 journal_write_revoke_records(journal, commit_transaction, write_op);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 /*
509 * If we found any dirty or locked buffers, then we should have
510 * looped back up to the write_out_data label. If there weren't
511 * any then journal_clean_data_list should have wiped the list
512 * clean by now, so check that it is in fact empty.
513 */
514 J_ASSERT (commit_transaction->t_sync_datalist == NULL);
515
516 jbd_debug (3, "JBD: commit phase 3\n");
517
518 /*
519 * Way to go: we have now written out all of the data for a
520 * transaction! Now comes the tricky part: we need to write out
521 * metadata. Loop over the transaction's entire buffer list:
522 */
Mingming Cao772279c2008-05-14 16:05:41 -0700523 spin_lock(&journal->j_state_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 commit_transaction->t_state = T_COMMIT;
Mingming Cao772279c2008-05-14 16:05:41 -0700525 spin_unlock(&journal->j_state_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526
Josef Bacik5b9a4992008-04-28 02:16:12 -0700527 J_ASSERT(commit_transaction->t_nr_buffers <=
528 commit_transaction->t_outstanding_credits);
529
Linus Torvalds1da177e2005-04-16 15:20:36 -0700530 descriptor = NULL;
531 bufs = 0;
532 while (commit_transaction->t_buffers) {
533
534 /* Find the next buffer to be journaled... */
535
536 jh = commit_transaction->t_buffers;
537
538 /* If we're in abort mode, we just un-journal the buffer and
Hidehiro Kawai885e3532008-10-18 20:27:54 -0700539 release it. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540
541 if (is_journal_aborted(journal)) {
Hidehiro Kawai885e3532008-10-18 20:27:54 -0700542 clear_buffer_jbddirty(jh2bh(jh));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543 JBUFFER_TRACE(jh, "journal is aborting: refile");
544 journal_refile_buffer(journal, jh);
545 /* If that was the last one, we need to clean up
546 * any descriptor buffers which may have been
547 * already allocated, even if we are now
548 * aborting. */
549 if (!commit_transaction->t_buffers)
550 goto start_journal_io;
551 continue;
552 }
553
554 /* Make sure we have a descriptor block in which to
555 record the metadata buffer. */
556
557 if (!descriptor) {
558 struct buffer_head *bh;
559
560 J_ASSERT (bufs == 0);
561
562 jbd_debug(4, "JBD: get descriptor\n");
563
564 descriptor = journal_get_descriptor_buffer(journal);
565 if (!descriptor) {
Jan Kara7a266e72007-10-18 23:39:22 -0700566 journal_abort(journal, -EIO);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 continue;
568 }
569
570 bh = jh2bh(descriptor);
571 jbd_debug(4, "JBD: got buffer %llu (%p)\n",
572 (unsigned long long)bh->b_blocknr, bh->b_data);
573 header = (journal_header_t *)&bh->b_data[0];
574 header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
575 header->h_blocktype = cpu_to_be32(JFS_DESCRIPTOR_BLOCK);
576 header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
577
578 tagp = &bh->b_data[sizeof(journal_header_t)];
579 space_left = bh->b_size - sizeof(journal_header_t);
580 first_tag = 1;
581 set_buffer_jwrite(bh);
582 set_buffer_dirty(bh);
583 wbuf[bufs++] = bh;
584
585 /* Record it so that we can wait for IO
586 completion later */
587 BUFFER_TRACE(bh, "ph3: file as descriptor");
588 journal_file_buffer(descriptor, commit_transaction,
589 BJ_LogCtl);
590 }
591
592 /* Where is the buffer to be written? */
593
594 err = journal_next_log_block(journal, &blocknr);
595 /* If the block mapping failed, just abandon the buffer
596 and repeat this loop: we'll fall into the
597 refile-on-abort condition above. */
598 if (err) {
Jan Kara7a266e72007-10-18 23:39:22 -0700599 journal_abort(journal, err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600 continue;
601 }
602
603 /*
604 * start_this_handle() uses t_outstanding_credits to determine
605 * the free space in the log, but this counter is changed
606 * by journal_next_log_block() also.
607 */
608 commit_transaction->t_outstanding_credits--;
609
610 /* Bump b_count to prevent truncate from stumbling over
611 the shadowed buffer! @@@ This can go if we ever get
612 rid of the BJ_IO/BJ_Shadow pairing of buffers. */
613 atomic_inc(&jh2bh(jh)->b_count);
614
615 /* Make a temporary IO buffer with which to write it out
616 (this will requeue both the metadata buffer and the
617 temporary IO buffer). new_bh goes on BJ_IO*/
618
619 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
620 /*
621 * akpm: journal_write_metadata_buffer() sets
622 * new_bh->b_transaction to commit_transaction.
623 * We need to clean this up before we release new_bh
624 * (which is of type BJ_IO)
625 */
626 JBUFFER_TRACE(jh, "ph3: write metadata");
627 flags = journal_write_metadata_buffer(commit_transaction,
628 jh, &new_jh, blocknr);
629 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state);
630 wbuf[bufs++] = jh2bh(new_jh);
631
632 /* Record the new block's tag in the current descriptor
633 buffer */
634
635 tag_flag = 0;
636 if (flags & 1)
637 tag_flag |= JFS_FLAG_ESCAPE;
638 if (!first_tag)
639 tag_flag |= JFS_FLAG_SAME_UUID;
640
641 tag = (journal_block_tag_t *) tagp;
642 tag->t_blocknr = cpu_to_be32(jh2bh(jh)->b_blocknr);
643 tag->t_flags = cpu_to_be32(tag_flag);
644 tagp += sizeof(journal_block_tag_t);
645 space_left -= sizeof(journal_block_tag_t);
646
647 if (first_tag) {
648 memcpy (tagp, journal->j_uuid, 16);
649 tagp += 16;
650 space_left -= 16;
651 first_tag = 0;
652 }
653
654 /* If there's no more to do, or if the descriptor is full,
655 let the IO rip! */
656
657 if (bufs == journal->j_wbufsize ||
658 commit_transaction->t_buffers == NULL ||
659 space_left < sizeof(journal_block_tag_t) + 16) {
660
661 jbd_debug(4, "JBD: Submit %d IOs\n", bufs);
662
663 /* Write an end-of-descriptor marker before
664 submitting the IOs. "tag" still points to
665 the last tag we set up. */
666
667 tag->t_flags |= cpu_to_be32(JFS_FLAG_LAST_TAG);
668
669start_journal_io:
670 for (i = 0; i < bufs; i++) {
671 struct buffer_head *bh = wbuf[i];
672 lock_buffer(bh);
673 clear_buffer_dirty(bh);
674 set_buffer_uptodate(bh);
675 bh->b_end_io = journal_end_buffer_io_sync;
Theodore Ts'o512a0042009-03-27 22:14:27 -0400676 submit_bh(write_op, bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 }
678 cond_resched();
679
680 /* Force a new descriptor to be generated next
681 time round the loop. */
682 descriptor = NULL;
683 bufs = 0;
684 }
685 }
686
687 /* Lo and behold: we have just managed to send a transaction to
688 the log. Before we can commit it, wait for the IO so far to
689 complete. Control buffers being written are on the
690 transaction's t_log_list queue, and metadata buffers are on
691 the t_iobuf_list queue.
692
693 Wait for the buffers in reverse order. That way we are
694 less likely to be woken up until all IOs have completed, and
695 so we incur less scheduling load.
696 */
697
698 jbd_debug(3, "JBD: commit phase 4\n");
699
700 /*
701 * akpm: these are BJ_IO, and j_list_lock is not needed.
702 * See __journal_try_to_free_buffer.
703 */
704wait_for_iobuf:
705 while (commit_transaction->t_iobuf_list != NULL) {
706 struct buffer_head *bh;
707
708 jh = commit_transaction->t_iobuf_list->b_tprev;
709 bh = jh2bh(jh);
710 if (buffer_locked(bh)) {
711 wait_on_buffer(bh);
712 goto wait_for_iobuf;
713 }
714 if (cond_resched())
715 goto wait_for_iobuf;
716
717 if (unlikely(!buffer_uptodate(bh)))
718 err = -EIO;
719
720 clear_buffer_jwrite(bh);
721
722 JBUFFER_TRACE(jh, "ph4: unfile after journal write");
723 journal_unfile_buffer(journal, jh);
724
725 /*
726 * ->t_iobuf_list should contain only dummy buffer_heads
727 * which were created by journal_write_metadata_buffer().
728 */
729 BUFFER_TRACE(bh, "dumping temporary bh");
730 journal_put_journal_head(jh);
731 __brelse(bh);
732 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
733 free_buffer_head(bh);
734
735 /* We also have to unlock and free the corresponding
736 shadowed buffer */
737 jh = commit_transaction->t_shadow_list->b_tprev;
738 bh = jh2bh(jh);
739 clear_bit(BH_JWrite, &bh->b_state);
740 J_ASSERT_BH(bh, buffer_jbddirty(bh));
741
742 /* The metadata is now released for reuse, but we need
743 to remember it against this transaction so that when
744 we finally commit, we can do any checkpointing
745 required. */
746 JBUFFER_TRACE(jh, "file as BJ_Forget");
747 journal_file_buffer(jh, commit_transaction, BJ_Forget);
748 /* Wake up any transactions which were waiting for this
749 IO to complete */
750 wake_up_bit(&bh->b_state, BH_Unshadow);
751 JBUFFER_TRACE(jh, "brelse shadowed buffer");
752 __brelse(bh);
753 }
754
755 J_ASSERT (commit_transaction->t_shadow_list == NULL);
756
757 jbd_debug(3, "JBD: commit phase 5\n");
758
759 /* Here we wait for the revoke record and descriptor record buffers */
760 wait_for_ctlbuf:
761 while (commit_transaction->t_log_list != NULL) {
762 struct buffer_head *bh;
763
764 jh = commit_transaction->t_log_list->b_tprev;
765 bh = jh2bh(jh);
766 if (buffer_locked(bh)) {
767 wait_on_buffer(bh);
768 goto wait_for_ctlbuf;
769 }
770 if (cond_resched())
771 goto wait_for_ctlbuf;
772
773 if (unlikely(!buffer_uptodate(bh)))
774 err = -EIO;
775
776 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
777 clear_buffer_jwrite(bh);
778 journal_unfile_buffer(journal, jh);
779 journal_put_journal_head(jh);
780 __brelse(bh); /* One for getblk */
781 /* AKPM: bforget here */
782 }
783
Hidehiro Kawaid1645e52008-10-18 20:27:53 -0700784 if (err)
785 journal_abort(journal, err);
786
Linus Torvalds1da177e2005-04-16 15:20:36 -0700787 jbd_debug(3, "JBD: commit phase 6\n");
788
Jan Kara03f4d802010-04-15 22:16:24 +0200789 /* All metadata is written, now write commit record and do cleanup */
790 spin_lock(&journal->j_state_lock);
791 J_ASSERT(commit_transaction->t_state == T_COMMIT);
792 commit_transaction->t_state = T_COMMIT_RECORD;
793 spin_unlock(&journal->j_state_lock);
794
Linus Torvalds1da177e2005-04-16 15:20:36 -0700795 if (journal_write_commit_record(journal, commit_transaction))
796 err = -EIO;
797
798 if (err)
Jan Kara7a266e72007-10-18 23:39:22 -0700799 journal_abort(journal, err);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700800
801 /* End of a transaction! Finally, we can do checkpoint
802 processing: any buffers committed as a result of this
803 transaction can be removed from any checkpoint list it was on
804 before. */
805
806 jbd_debug(3, "JBD: commit phase 7\n");
807
808 J_ASSERT(commit_transaction->t_sync_datalist == NULL);
809 J_ASSERT(commit_transaction->t_buffers == NULL);
810 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
811 J_ASSERT(commit_transaction->t_iobuf_list == NULL);
812 J_ASSERT(commit_transaction->t_shadow_list == NULL);
813 J_ASSERT(commit_transaction->t_log_list == NULL);
814
815restart_loop:
Jan Karae6c9f5c2005-09-06 15:19:09 -0700816 /*
817 * As there are other places (journal_unmap_buffer()) adding buffers
818 * to this list we have to be careful and hold the j_list_lock.
819 */
820 spin_lock(&journal->j_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700821 while (commit_transaction->t_forget) {
822 transaction_t *cp_transaction;
823 struct buffer_head *bh;
824
825 jh = commit_transaction->t_forget;
Jan Karae6c9f5c2005-09-06 15:19:09 -0700826 spin_unlock(&journal->j_list_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700827 bh = jh2bh(jh);
828 jbd_lock_bh_state(bh);
829 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction ||
830 jh->b_transaction == journal->j_running_transaction);
831
832 /*
833 * If there is undo-protected committed data against
834 * this buffer, then we can remove it now. If it is a
835 * buffer needing such protection, the old frozen_data
836 * field now points to a committed version of the
837 * buffer, so rotate that field to the new committed
838 * data.
839 *
840 * Otherwise, we can just throw away the frozen data now.
841 */
842 if (jh->b_committed_data) {
Mingming Caoc089d492007-10-16 18:38:25 -0400843 jbd_free(jh->b_committed_data, bh->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700844 jh->b_committed_data = NULL;
845 if (jh->b_frozen_data) {
846 jh->b_committed_data = jh->b_frozen_data;
847 jh->b_frozen_data = NULL;
848 }
849 } else if (jh->b_frozen_data) {
Mingming Caoc089d492007-10-16 18:38:25 -0400850 jbd_free(jh->b_frozen_data, bh->b_size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851 jh->b_frozen_data = NULL;
852 }
853
854 spin_lock(&journal->j_list_lock);
855 cp_transaction = jh->b_cp_transaction;
856 if (cp_transaction) {
857 JBUFFER_TRACE(jh, "remove from old cp transaction");
858 __journal_remove_checkpoint(jh);
859 }
860
861 /* Only re-checkpoint the buffer_head if it is marked
862 * dirty. If the buffer was added to the BJ_Forget list
863 * by journal_forget, it may no longer be dirty and
864 * there's no point in keeping a checkpoint record for
865 * it. */
866
867 /* A buffer which has been freed while still being
868 * journaled by a previous transaction may end up still
869 * being dirty here, but we want to avoid writing back
Jan Kara86963912010-02-16 20:37:12 +0100870 * that buffer in the future after the "add to orphan"
871 * operation been committed, That's not only a performance
872 * gain, it also stops aliasing problems if the buffer is
873 * left behind for writeback and gets reallocated for another
Linus Torvalds1da177e2005-04-16 15:20:36 -0700874 * use in a different page. */
Jan Kara86963912010-02-16 20:37:12 +0100875 if (buffer_freed(bh) && !jh->b_next_transaction) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 clear_buffer_freed(bh);
877 clear_buffer_jbddirty(bh);
878 }
879
880 if (buffer_jbddirty(bh)) {
881 JBUFFER_TRACE(jh, "add to new checkpointing trans");
882 __journal_insert_checkpoint(jh, commit_transaction);
Hidehiro Kawai885e3532008-10-18 20:27:54 -0700883 if (is_journal_aborted(journal))
884 clear_buffer_jbddirty(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 JBUFFER_TRACE(jh, "refile for checkpoint writeback");
886 __journal_refile_buffer(jh);
887 jbd_unlock_bh_state(bh);
888 } else {
889 J_ASSERT_BH(bh, !buffer_dirty(bh));
Jan Kara9ada7342006-06-23 02:05:25 -0700890 /* The buffer on BJ_Forget list and not jbddirty means
891 * it has been freed by this transaction and hence it
892 * could not have been reallocated until this
893 * transaction has committed. *BUT* it could be
894 * reallocated once we have written all the data to
895 * disk and before we process the buffer on BJ_Forget
896 * list. */
897 JBUFFER_TRACE(jh, "refile or unfile freed buffer");
898 __journal_refile_buffer(jh);
899 if (!jh->b_transaction) {
900 jbd_unlock_bh_state(bh);
901 /* needs a brelse */
902 journal_remove_journal_head(bh);
903 release_buffer_page(bh);
904 } else
905 jbd_unlock_bh_state(bh);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 }
Jan Karae6c9f5c2005-09-06 15:19:09 -0700907 cond_resched_lock(&journal->j_list_lock);
908 }
909 spin_unlock(&journal->j_list_lock);
910 /*
Jan Karad4beaf42007-12-04 23:45:27 -0800911 * This is a bit sleazy. We use j_list_lock to protect transition
912 * of a transaction into T_FINISHED state and calling
913 * __journal_drop_transaction(). Otherwise we could race with
914 * other checkpointing code processing the transaction...
Jan Karae6c9f5c2005-09-06 15:19:09 -0700915 */
916 spin_lock(&journal->j_state_lock);
917 spin_lock(&journal->j_list_lock);
918 /*
919 * Now recheck if some buffers did not get attached to the transaction
920 * while the lock was dropped...
921 */
922 if (commit_transaction->t_forget) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 spin_unlock(&journal->j_list_lock);
Jan Karae6c9f5c2005-09-06 15:19:09 -0700924 spin_unlock(&journal->j_state_lock);
925 goto restart_loop;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926 }
927
928 /* Done with this transaction! */
929
930 jbd_debug(3, "JBD: commit phase 8\n");
931
Jan Kara03f4d802010-04-15 22:16:24 +0200932 J_ASSERT(commit_transaction->t_state == T_COMMIT_RECORD);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933
Linus Torvalds1da177e2005-04-16 15:20:36 -0700934 commit_transaction->t_state = T_FINISHED;
935 J_ASSERT(commit_transaction == journal->j_committing_transaction);
936 journal->j_commit_sequence = commit_transaction->t_tid;
937 journal->j_committing_transaction = NULL;
Josef Bacikf420d4d2009-01-07 18:07:24 -0800938 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
939
940 /*
941 * weight the commit time higher than the average time so we don't
942 * react too strongly to vast changes in commit time
943 */
944 if (likely(journal->j_average_commit_time))
945 journal->j_average_commit_time = (commit_time*3 +
946 journal->j_average_commit_time) / 4;
947 else
948 journal->j_average_commit_time = commit_time;
949
Linus Torvalds1da177e2005-04-16 15:20:36 -0700950 spin_unlock(&journal->j_state_lock);
951
Jan Karafe28e422007-07-15 23:37:18 -0700952 if (commit_transaction->t_checkpoint_list == NULL &&
953 commit_transaction->t_checkpoint_io_list == NULL) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700954 __journal_drop_transaction(journal, commit_transaction);
955 } else {
956 if (journal->j_checkpoint_transactions == NULL) {
957 journal->j_checkpoint_transactions = commit_transaction;
958 commit_transaction->t_cpnext = commit_transaction;
959 commit_transaction->t_cpprev = commit_transaction;
960 } else {
961 commit_transaction->t_cpnext =
962 journal->j_checkpoint_transactions;
963 commit_transaction->t_cpprev =
964 commit_transaction->t_cpnext->t_cpprev;
965 commit_transaction->t_cpnext->t_cpprev =
966 commit_transaction;
967 commit_transaction->t_cpprev->t_cpnext =
968 commit_transaction;
969 }
970 }
971 spin_unlock(&journal->j_list_lock);
972
973 jbd_debug(1, "JBD: commit %d complete, head %d\n",
974 journal->j_commit_sequence, journal->j_tail_sequence);
975
976 wake_up(&journal->j_wait_done_commit);
977}