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Dave Kleikamp470decc2006-10-11 01:20:57 -07001/*
Mingming Caof7f4bcc2006-10-11 01:20:59 -07002 * linux/fs/jbd2/commit.c
Dave Kleikamp470decc2006-10-11 01:20:57 -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>
Mingming Caof7f4bcc2006-10-11 01:20:59 -070018#include <linux/jbd2.h>
Dave Kleikamp470decc2006-10-11 01:20:57 -070019#include <linux/errno.h>
20#include <linux/slab.h>
21#include <linux/mm.h>
22#include <linux/pagemap.h>
Dave Kleikamp470decc2006-10-11 01:20:57 -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
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700113 descriptor = jbd2_journal_get_descriptor_buffer(journal);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700114 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;
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700122 tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
123 tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700124 tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
125 }
126
127 JBUFFER_TRACE(descriptor, "write commit block");
128 set_buffer_dirty(bh);
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700129 if (journal->j_flags & JBD2_BARRIER) {
Dave Kleikamp470decc2006-10-11 01:20:57 -0700130 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);
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700147 journal->j_flags &= ~JBD2_BARRIER;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700148 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() */
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700157 jbd2_journal_put_journal_head(descriptor);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700158
159 return (ret == -EIO);
160}
161
162static 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;
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700241 __jbd2_journal_file_buffer(jh, commit_transaction,
Dave Kleikamp470decc2006-10-11 01:20:57 -0700242 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 Hifumi12603922006-12-06 20:39:17 -0800250 } else if (!locked && buffer_locked(bh)) {
251 __jbd2_journal_file_buffer(jh, commit_transaction,
252 BJ_Locked);
253 jbd_unlock_bh_state(bh);
254 put_bh(bh);
255 } else {
Dave Kleikamp470decc2006-10-11 01:20:57 -0700256 BUFFER_TRACE(bh, "writeout complete: unfile");
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700257 __jbd2_journal_unfile_buffer(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700258 jbd_unlock_bh_state(bh);
259 if (locked)
260 unlock_buffer(bh);
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700261 jbd2_journal_remove_journal_head(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700262 /* Once for our safety reference, once for
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700263 * jbd2_journal_remove_journal_head() */
Dave Kleikamp470decc2006-10-11 01:20:57 -0700264 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
Zach Brownb517bea2006-10-11 01:21:08 -0700277static inline void write_tag_block(int tag_bytes, journal_block_tag_t *tag,
Mingming Cao18eba7a2006-10-11 01:21:13 -0700278 unsigned long long block)
Zach Brownb517bea2006-10-11 01:21:08 -0700279{
280 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
Mingming Caocd02ff02007-10-16 18:38:25 -0400281 if (tag_bytes > JBD2_TAG_SIZE32)
Zach Brownb517bea2006-10-11 01:21:08 -0700282 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
283}
284
Dave Kleikamp470decc2006-10-11 01:20:57 -0700285/*
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700286 * jbd2_journal_commit_transaction
Dave Kleikamp470decc2006-10-11 01:20:57 -0700287 *
288 * The primary function for committing a transaction to the log. This
289 * function is called by the journal thread to begin a complete commit.
290 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700291void jbd2_journal_commit_transaction(journal_t *journal)
Dave Kleikamp470decc2006-10-11 01:20:57 -0700292{
293 transaction_t *commit_transaction;
294 struct journal_head *jh, *new_jh, *descriptor;
295 struct buffer_head **wbuf = journal->j_wbuf;
296 int bufs;
297 int flags;
298 int err;
Mingming Cao18eba7a2006-10-11 01:21:13 -0700299 unsigned long long blocknr;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700300 char *tagp = NULL;
301 journal_header_t *header;
302 journal_block_tag_t *tag = NULL;
303 int space_left = 0;
304 int first_tag = 0;
305 int tag_flag;
306 int i;
Zach Brownb517bea2006-10-11 01:21:08 -0700307 int tag_bytes = journal_tag_bytes(journal);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700308
309 /*
310 * First job: lock down the current transaction and wait for
311 * all outstanding updates to complete.
312 */
313
314#ifdef COMMIT_STATS
315 spin_lock(&journal->j_list_lock);
316 summarise_journal_usage(journal);
317 spin_unlock(&journal->j_list_lock);
318#endif
319
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700320 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
321 if (journal->j_flags & JBD2_FLUSHED) {
Dave Kleikamp470decc2006-10-11 01:20:57 -0700322 jbd_debug(3, "super block updated\n");
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700323 jbd2_journal_update_superblock(journal, 1);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700324 } else {
325 jbd_debug(3, "superblock not updated\n");
326 }
327
328 J_ASSERT(journal->j_running_transaction != NULL);
329 J_ASSERT(journal->j_committing_transaction == NULL);
330
331 commit_transaction = journal->j_running_transaction;
332 J_ASSERT(commit_transaction->t_state == T_RUNNING);
333
334 jbd_debug(1, "JBD: starting commit of transaction %d\n",
335 commit_transaction->t_tid);
336
337 spin_lock(&journal->j_state_lock);
338 commit_transaction->t_state = T_LOCKED;
339
340 spin_lock(&commit_transaction->t_handle_lock);
341 while (commit_transaction->t_updates) {
342 DEFINE_WAIT(wait);
343
344 prepare_to_wait(&journal->j_wait_updates, &wait,
345 TASK_UNINTERRUPTIBLE);
346 if (commit_transaction->t_updates) {
347 spin_unlock(&commit_transaction->t_handle_lock);
348 spin_unlock(&journal->j_state_lock);
349 schedule();
350 spin_lock(&journal->j_state_lock);
351 spin_lock(&commit_transaction->t_handle_lock);
352 }
353 finish_wait(&journal->j_wait_updates, &wait);
354 }
355 spin_unlock(&commit_transaction->t_handle_lock);
356
357 J_ASSERT (commit_transaction->t_outstanding_credits <=
358 journal->j_max_transaction_buffers);
359
360 /*
361 * First thing we are allowed to do is to discard any remaining
362 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
363 * that there are no such buffers: if a large filesystem
364 * operation like a truncate needs to split itself over multiple
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700365 * transactions, then it may try to do a jbd2_journal_restart() while
Dave Kleikamp470decc2006-10-11 01:20:57 -0700366 * there are still BJ_Reserved buffers outstanding. These must
367 * be released cleanly from the current transaction.
368 *
369 * In this case, the filesystem must still reserve write access
370 * again before modifying the buffer in the new transaction, but
371 * we do not require it to remember exactly which old buffers it
372 * has reserved. This is consistent with the existing behaviour
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700373 * that multiple jbd2_journal_get_write_access() calls to the same
Dave Kleikamp470decc2006-10-11 01:20:57 -0700374 * buffer are perfectly permissable.
375 */
376 while (commit_transaction->t_reserved_list) {
377 jh = commit_transaction->t_reserved_list;
378 JBUFFER_TRACE(jh, "reserved, unused: refile");
379 /*
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700380 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
Dave Kleikamp470decc2006-10-11 01:20:57 -0700381 * leave undo-committed data.
382 */
383 if (jh->b_committed_data) {
384 struct buffer_head *bh = jh2bh(jh);
385
386 jbd_lock_bh_state(bh);
Mingming Caoaf1e76d2007-10-16 18:38:25 -0400387 jbd2_free(jh->b_committed_data, bh->b_size);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700388 jh->b_committed_data = NULL;
389 jbd_unlock_bh_state(bh);
390 }
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700391 jbd2_journal_refile_buffer(journal, jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700392 }
393
394 /*
395 * Now try to drop any written-back buffers from the journal's
396 * checkpoint lists. We do this *before* commit because it potentially
397 * frees some memory
398 */
399 spin_lock(&journal->j_list_lock);
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700400 __jbd2_journal_clean_checkpoint_list(journal);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700401 spin_unlock(&journal->j_list_lock);
402
403 jbd_debug (3, "JBD: commit phase 1\n");
404
405 /*
406 * Switch to a new revoke table.
407 */
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700408 jbd2_journal_switch_revoke_table(journal);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700409
410 commit_transaction->t_state = T_FLUSH;
411 journal->j_committing_transaction = commit_transaction;
412 journal->j_running_transaction = NULL;
413 commit_transaction->t_log_start = journal->j_head;
414 wake_up(&journal->j_wait_transaction_locked);
415 spin_unlock(&journal->j_state_lock);
416
417 jbd_debug (3, "JBD: commit phase 2\n");
418
419 /*
420 * First, drop modified flag: all accesses to the buffers
421 * will be tracked for a new trasaction only -bzzz
422 */
423 spin_lock(&journal->j_list_lock);
424 if (commit_transaction->t_buffers) {
425 new_jh = jh = commit_transaction->t_buffers->b_tnext;
426 do {
427 J_ASSERT_JH(new_jh, new_jh->b_modified == 1 ||
428 new_jh->b_modified == 0);
429 new_jh->b_modified = 0;
430 new_jh = new_jh->b_tnext;
431 } while (new_jh != jh);
432 }
433 spin_unlock(&journal->j_list_lock);
434
435 /*
436 * Now start flushing things to disk, in the order they appear
437 * on the transaction lists. Data blocks go first.
438 */
439 err = 0;
440 journal_submit_data_buffers(journal, commit_transaction);
441
442 /*
443 * Wait for all previously submitted IO to complete.
444 */
445 spin_lock(&journal->j_list_lock);
446 while (commit_transaction->t_locked_list) {
447 struct buffer_head *bh;
448
449 jh = commit_transaction->t_locked_list->b_tprev;
450 bh = jh2bh(jh);
451 get_bh(bh);
452 if (buffer_locked(bh)) {
453 spin_unlock(&journal->j_list_lock);
454 wait_on_buffer(bh);
455 if (unlikely(!buffer_uptodate(bh)))
456 err = -EIO;
457 spin_lock(&journal->j_list_lock);
458 }
459 if (!inverted_lock(journal, bh)) {
460 put_bh(bh);
461 spin_lock(&journal->j_list_lock);
462 continue;
463 }
464 if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700465 __jbd2_journal_unfile_buffer(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700466 jbd_unlock_bh_state(bh);
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700467 jbd2_journal_remove_journal_head(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700468 put_bh(bh);
469 } else {
470 jbd_unlock_bh_state(bh);
471 }
472 put_bh(bh);
473 cond_resched_lock(&journal->j_list_lock);
474 }
475 spin_unlock(&journal->j_list_lock);
476
477 if (err)
Jan Karaa7fa2ba2007-10-16 18:38:25 -0400478 jbd2_journal_abort(journal, err);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700479
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700480 jbd2_journal_write_revoke_records(journal, commit_transaction);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700481
482 jbd_debug(3, "JBD: commit phase 2\n");
483
484 /*
485 * If we found any dirty or locked buffers, then we should have
486 * looped back up to the write_out_data label. If there weren't
487 * any then journal_clean_data_list should have wiped the list
488 * clean by now, so check that it is in fact empty.
489 */
490 J_ASSERT (commit_transaction->t_sync_datalist == NULL);
491
492 jbd_debug (3, "JBD: commit phase 3\n");
493
494 /*
495 * Way to go: we have now written out all of the data for a
496 * transaction! Now comes the tricky part: we need to write out
497 * metadata. Loop over the transaction's entire buffer list:
498 */
499 commit_transaction->t_state = T_COMMIT;
500
501 descriptor = NULL;
502 bufs = 0;
503 while (commit_transaction->t_buffers) {
504
505 /* Find the next buffer to be journaled... */
506
507 jh = commit_transaction->t_buffers;
508
509 /* If we're in abort mode, we just un-journal the buffer and
510 release it for background writing. */
511
512 if (is_journal_aborted(journal)) {
513 JBUFFER_TRACE(jh, "journal is aborting: refile");
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700514 jbd2_journal_refile_buffer(journal, jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700515 /* If that was the last one, we need to clean up
516 * any descriptor buffers which may have been
517 * already allocated, even if we are now
518 * aborting. */
519 if (!commit_transaction->t_buffers)
520 goto start_journal_io;
521 continue;
522 }
523
524 /* Make sure we have a descriptor block in which to
525 record the metadata buffer. */
526
527 if (!descriptor) {
528 struct buffer_head *bh;
529
530 J_ASSERT (bufs == 0);
531
532 jbd_debug(4, "JBD: get descriptor\n");
533
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700534 descriptor = jbd2_journal_get_descriptor_buffer(journal);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700535 if (!descriptor) {
Jan Karaa7fa2ba2007-10-16 18:38:25 -0400536 jbd2_journal_abort(journal, -EIO);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700537 continue;
538 }
539
540 bh = jh2bh(descriptor);
541 jbd_debug(4, "JBD: got buffer %llu (%p)\n",
542 (unsigned long long)bh->b_blocknr, bh->b_data);
543 header = (journal_header_t *)&bh->b_data[0];
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700544 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
545 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700546 header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
547
548 tagp = &bh->b_data[sizeof(journal_header_t)];
549 space_left = bh->b_size - sizeof(journal_header_t);
550 first_tag = 1;
551 set_buffer_jwrite(bh);
552 set_buffer_dirty(bh);
553 wbuf[bufs++] = bh;
554
555 /* Record it so that we can wait for IO
556 completion later */
557 BUFFER_TRACE(bh, "ph3: file as descriptor");
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700558 jbd2_journal_file_buffer(descriptor, commit_transaction,
Dave Kleikamp470decc2006-10-11 01:20:57 -0700559 BJ_LogCtl);
560 }
561
562 /* Where is the buffer to be written? */
563
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700564 err = jbd2_journal_next_log_block(journal, &blocknr);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700565 /* If the block mapping failed, just abandon the buffer
566 and repeat this loop: we'll fall into the
567 refile-on-abort condition above. */
568 if (err) {
Jan Karaa7fa2ba2007-10-16 18:38:25 -0400569 jbd2_journal_abort(journal, err);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700570 continue;
571 }
572
573 /*
574 * start_this_handle() uses t_outstanding_credits to determine
575 * the free space in the log, but this counter is changed
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700576 * by jbd2_journal_next_log_block() also.
Dave Kleikamp470decc2006-10-11 01:20:57 -0700577 */
578 commit_transaction->t_outstanding_credits--;
579
580 /* Bump b_count to prevent truncate from stumbling over
581 the shadowed buffer! @@@ This can go if we ever get
582 rid of the BJ_IO/BJ_Shadow pairing of buffers. */
583 atomic_inc(&jh2bh(jh)->b_count);
584
585 /* Make a temporary IO buffer with which to write it out
586 (this will requeue both the metadata buffer and the
587 temporary IO buffer). new_bh goes on BJ_IO*/
588
589 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
590 /*
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700591 * akpm: jbd2_journal_write_metadata_buffer() sets
Dave Kleikamp470decc2006-10-11 01:20:57 -0700592 * new_bh->b_transaction to commit_transaction.
593 * We need to clean this up before we release new_bh
594 * (which is of type BJ_IO)
595 */
596 JBUFFER_TRACE(jh, "ph3: write metadata");
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700597 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
Dave Kleikamp470decc2006-10-11 01:20:57 -0700598 jh, &new_jh, blocknr);
599 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state);
600 wbuf[bufs++] = jh2bh(new_jh);
601
602 /* Record the new block's tag in the current descriptor
603 buffer */
604
605 tag_flag = 0;
606 if (flags & 1)
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700607 tag_flag |= JBD2_FLAG_ESCAPE;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700608 if (!first_tag)
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700609 tag_flag |= JBD2_FLAG_SAME_UUID;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700610
611 tag = (journal_block_tag_t *) tagp;
Zach Brownb517bea2006-10-11 01:21:08 -0700612 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700613 tag->t_flags = cpu_to_be32(tag_flag);
Zach Brownb517bea2006-10-11 01:21:08 -0700614 tagp += tag_bytes;
615 space_left -= tag_bytes;
Dave Kleikamp470decc2006-10-11 01:20:57 -0700616
617 if (first_tag) {
618 memcpy (tagp, journal->j_uuid, 16);
619 tagp += 16;
620 space_left -= 16;
621 first_tag = 0;
622 }
623
624 /* If there's no more to do, or if the descriptor is full,
625 let the IO rip! */
626
627 if (bufs == journal->j_wbufsize ||
628 commit_transaction->t_buffers == NULL ||
Zach Brownb517bea2006-10-11 01:21:08 -0700629 space_left < tag_bytes + 16) {
Dave Kleikamp470decc2006-10-11 01:20:57 -0700630
631 jbd_debug(4, "JBD: Submit %d IOs\n", bufs);
632
633 /* Write an end-of-descriptor marker before
634 submitting the IOs. "tag" still points to
635 the last tag we set up. */
636
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700637 tag->t_flags |= cpu_to_be32(JBD2_FLAG_LAST_TAG);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700638
639start_journal_io:
640 for (i = 0; i < bufs; i++) {
641 struct buffer_head *bh = wbuf[i];
642 lock_buffer(bh);
643 clear_buffer_dirty(bh);
644 set_buffer_uptodate(bh);
645 bh->b_end_io = journal_end_buffer_io_sync;
646 submit_bh(WRITE, bh);
647 }
648 cond_resched();
649
650 /* Force a new descriptor to be generated next
651 time round the loop. */
652 descriptor = NULL;
653 bufs = 0;
654 }
655 }
656
657 /* Lo and behold: we have just managed to send a transaction to
658 the log. Before we can commit it, wait for the IO so far to
659 complete. Control buffers being written are on the
660 transaction's t_log_list queue, and metadata buffers are on
661 the t_iobuf_list queue.
662
663 Wait for the buffers in reverse order. That way we are
664 less likely to be woken up until all IOs have completed, and
665 so we incur less scheduling load.
666 */
667
668 jbd_debug(3, "JBD: commit phase 4\n");
669
670 /*
671 * akpm: these are BJ_IO, and j_list_lock is not needed.
672 * See __journal_try_to_free_buffer.
673 */
674wait_for_iobuf:
675 while (commit_transaction->t_iobuf_list != NULL) {
676 struct buffer_head *bh;
677
678 jh = commit_transaction->t_iobuf_list->b_tprev;
679 bh = jh2bh(jh);
680 if (buffer_locked(bh)) {
681 wait_on_buffer(bh);
682 goto wait_for_iobuf;
683 }
684 if (cond_resched())
685 goto wait_for_iobuf;
686
687 if (unlikely(!buffer_uptodate(bh)))
688 err = -EIO;
689
690 clear_buffer_jwrite(bh);
691
692 JBUFFER_TRACE(jh, "ph4: unfile after journal write");
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700693 jbd2_journal_unfile_buffer(journal, jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700694
695 /*
696 * ->t_iobuf_list should contain only dummy buffer_heads
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700697 * which were created by jbd2_journal_write_metadata_buffer().
Dave Kleikamp470decc2006-10-11 01:20:57 -0700698 */
699 BUFFER_TRACE(bh, "dumping temporary bh");
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700700 jbd2_journal_put_journal_head(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700701 __brelse(bh);
702 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
703 free_buffer_head(bh);
704
705 /* We also have to unlock and free the corresponding
706 shadowed buffer */
707 jh = commit_transaction->t_shadow_list->b_tprev;
708 bh = jh2bh(jh);
709 clear_bit(BH_JWrite, &bh->b_state);
710 J_ASSERT_BH(bh, buffer_jbddirty(bh));
711
712 /* The metadata is now released for reuse, but we need
713 to remember it against this transaction so that when
714 we finally commit, we can do any checkpointing
715 required. */
716 JBUFFER_TRACE(jh, "file as BJ_Forget");
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700717 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700718 /* Wake up any transactions which were waiting for this
719 IO to complete */
720 wake_up_bit(&bh->b_state, BH_Unshadow);
721 JBUFFER_TRACE(jh, "brelse shadowed buffer");
722 __brelse(bh);
723 }
724
725 J_ASSERT (commit_transaction->t_shadow_list == NULL);
726
727 jbd_debug(3, "JBD: commit phase 5\n");
728
729 /* Here we wait for the revoke record and descriptor record buffers */
730 wait_for_ctlbuf:
731 while (commit_transaction->t_log_list != NULL) {
732 struct buffer_head *bh;
733
734 jh = commit_transaction->t_log_list->b_tprev;
735 bh = jh2bh(jh);
736 if (buffer_locked(bh)) {
737 wait_on_buffer(bh);
738 goto wait_for_ctlbuf;
739 }
740 if (cond_resched())
741 goto wait_for_ctlbuf;
742
743 if (unlikely(!buffer_uptodate(bh)))
744 err = -EIO;
745
746 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
747 clear_buffer_jwrite(bh);
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700748 jbd2_journal_unfile_buffer(journal, jh);
749 jbd2_journal_put_journal_head(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700750 __brelse(bh); /* One for getblk */
751 /* AKPM: bforget here */
752 }
753
754 jbd_debug(3, "JBD: commit phase 6\n");
755
756 if (journal_write_commit_record(journal, commit_transaction))
757 err = -EIO;
758
759 if (err)
Jan Karaa7fa2ba2007-10-16 18:38:25 -0400760 jbd2_journal_abort(journal, err);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700761
762 /* End of a transaction! Finally, we can do checkpoint
763 processing: any buffers committed as a result of this
764 transaction can be removed from any checkpoint list it was on
765 before. */
766
767 jbd_debug(3, "JBD: commit phase 7\n");
768
769 J_ASSERT(commit_transaction->t_sync_datalist == NULL);
770 J_ASSERT(commit_transaction->t_buffers == NULL);
771 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
772 J_ASSERT(commit_transaction->t_iobuf_list == NULL);
773 J_ASSERT(commit_transaction->t_shadow_list == NULL);
774 J_ASSERT(commit_transaction->t_log_list == NULL);
775
776restart_loop:
777 /*
778 * As there are other places (journal_unmap_buffer()) adding buffers
779 * to this list we have to be careful and hold the j_list_lock.
780 */
781 spin_lock(&journal->j_list_lock);
782 while (commit_transaction->t_forget) {
783 transaction_t *cp_transaction;
784 struct buffer_head *bh;
785
786 jh = commit_transaction->t_forget;
787 spin_unlock(&journal->j_list_lock);
788 bh = jh2bh(jh);
789 jbd_lock_bh_state(bh);
790 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction ||
791 jh->b_transaction == journal->j_running_transaction);
792
793 /*
794 * If there is undo-protected committed data against
795 * this buffer, then we can remove it now. If it is a
796 * buffer needing such protection, the old frozen_data
797 * field now points to a committed version of the
798 * buffer, so rotate that field to the new committed
799 * data.
800 *
801 * Otherwise, we can just throw away the frozen data now.
802 */
803 if (jh->b_committed_data) {
Mingming Caoaf1e76d2007-10-16 18:38:25 -0400804 jbd2_free(jh->b_committed_data, bh->b_size);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700805 jh->b_committed_data = NULL;
806 if (jh->b_frozen_data) {
807 jh->b_committed_data = jh->b_frozen_data;
808 jh->b_frozen_data = NULL;
809 }
810 } else if (jh->b_frozen_data) {
Mingming Caoaf1e76d2007-10-16 18:38:25 -0400811 jbd2_free(jh->b_frozen_data, bh->b_size);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700812 jh->b_frozen_data = NULL;
813 }
814
815 spin_lock(&journal->j_list_lock);
816 cp_transaction = jh->b_cp_transaction;
817 if (cp_transaction) {
818 JBUFFER_TRACE(jh, "remove from old cp transaction");
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700819 __jbd2_journal_remove_checkpoint(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700820 }
821
822 /* Only re-checkpoint the buffer_head if it is marked
823 * dirty. If the buffer was added to the BJ_Forget list
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700824 * by jbd2_journal_forget, it may no longer be dirty and
Dave Kleikamp470decc2006-10-11 01:20:57 -0700825 * there's no point in keeping a checkpoint record for
826 * it. */
827
828 /* A buffer which has been freed while still being
829 * journaled by a previous transaction may end up still
830 * being dirty here, but we want to avoid writing back
831 * that buffer in the future now that the last use has
832 * been committed. That's not only a performance gain,
833 * it also stops aliasing problems if the buffer is left
834 * behind for writeback and gets reallocated for another
835 * use in a different page. */
836 if (buffer_freed(bh)) {
837 clear_buffer_freed(bh);
838 clear_buffer_jbddirty(bh);
839 }
840
841 if (buffer_jbddirty(bh)) {
842 JBUFFER_TRACE(jh, "add to new checkpointing trans");
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700843 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700844 JBUFFER_TRACE(jh, "refile for checkpoint writeback");
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700845 __jbd2_journal_refile_buffer(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700846 jbd_unlock_bh_state(bh);
847 } else {
848 J_ASSERT_BH(bh, !buffer_dirty(bh));
849 /* The buffer on BJ_Forget list and not jbddirty means
850 * it has been freed by this transaction and hence it
851 * could not have been reallocated until this
852 * transaction has committed. *BUT* it could be
853 * reallocated once we have written all the data to
854 * disk and before we process the buffer on BJ_Forget
855 * list. */
856 JBUFFER_TRACE(jh, "refile or unfile freed buffer");
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700857 __jbd2_journal_refile_buffer(jh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700858 if (!jh->b_transaction) {
859 jbd_unlock_bh_state(bh);
860 /* needs a brelse */
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700861 jbd2_journal_remove_journal_head(bh);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700862 release_buffer_page(bh);
863 } else
864 jbd_unlock_bh_state(bh);
865 }
866 cond_resched_lock(&journal->j_list_lock);
867 }
868 spin_unlock(&journal->j_list_lock);
869 /*
870 * This is a bit sleazy. We borrow j_list_lock to protect
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700871 * journal->j_committing_transaction in __jbd2_journal_remove_checkpoint.
872 * Really, __jbd2_journal_remove_checkpoint should be using j_state_lock but
873 * it's a bit hassle to hold that across __jbd2_journal_remove_checkpoint
Dave Kleikamp470decc2006-10-11 01:20:57 -0700874 */
875 spin_lock(&journal->j_state_lock);
876 spin_lock(&journal->j_list_lock);
877 /*
878 * Now recheck if some buffers did not get attached to the transaction
879 * while the lock was dropped...
880 */
881 if (commit_transaction->t_forget) {
882 spin_unlock(&journal->j_list_lock);
883 spin_unlock(&journal->j_state_lock);
884 goto restart_loop;
885 }
886
887 /* Done with this transaction! */
888
889 jbd_debug(3, "JBD: commit phase 8\n");
890
891 J_ASSERT(commit_transaction->t_state == T_COMMIT);
892
893 commit_transaction->t_state = T_FINISHED;
894 J_ASSERT(commit_transaction == journal->j_committing_transaction);
895 journal->j_commit_sequence = commit_transaction->t_tid;
896 journal->j_committing_transaction = NULL;
897 spin_unlock(&journal->j_state_lock);
898
Jan Karaf89b7792007-07-15 23:37:20 -0700899 if (commit_transaction->t_checkpoint_list == NULL &&
900 commit_transaction->t_checkpoint_io_list == NULL) {
Mingming Caof7f4bcc2006-10-11 01:20:59 -0700901 __jbd2_journal_drop_transaction(journal, commit_transaction);
Dave Kleikamp470decc2006-10-11 01:20:57 -0700902 } else {
903 if (journal->j_checkpoint_transactions == NULL) {
904 journal->j_checkpoint_transactions = commit_transaction;
905 commit_transaction->t_cpnext = commit_transaction;
906 commit_transaction->t_cpprev = commit_transaction;
907 } else {
908 commit_transaction->t_cpnext =
909 journal->j_checkpoint_transactions;
910 commit_transaction->t_cpprev =
911 commit_transaction->t_cpnext->t_cpprev;
912 commit_transaction->t_cpnext->t_cpprev =
913 commit_transaction;
914 commit_transaction->t_cpprev->t_cpnext =
915 commit_transaction;
916 }
917 }
918 spin_unlock(&journal->j_list_lock);
919
920 jbd_debug(1, "JBD: commit %d complete, head %d\n",
921 journal->j_commit_sequence, journal->j_tail_sequence);
922
923 wake_up(&journal->j_wait_done_commit);
924}