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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * linux/fs/jbd2/commit.c
4 *
5 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
6 *
7 * Copyright 1998 Red Hat corp --- All Rights Reserved
8 *
9 * Journal commit routines for the generic filesystem journaling code;
10 * part of the ext2fs journaling system.
11 */
12
13#include <linux/time.h>
14#include <linux/fs.h>
15#include <linux/jbd2.h>
16#include <linux/errno.h>
17#include <linux/slab.h>
18#include <linux/mm.h>
19#include <linux/pagemap.h>
20#include <linux/jiffies.h>
21#include <linux/crc32.h>
22#include <linux/writeback.h>
23#include <linux/backing-dev.h>
24#include <linux/bio.h>
25#include <linux/blkdev.h>
26#include <linux/bitops.h>
27#include <trace/events/jbd2.h>
28
29/*
30 * IO end handler for temporary buffer_heads handling writes to the journal.
31 */
32static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
33{
34 struct buffer_head *orig_bh = bh->b_private;
35
36 BUFFER_TRACE(bh, "");
37 if (uptodate)
38 set_buffer_uptodate(bh);
39 else
40 clear_buffer_uptodate(bh);
41 if (orig_bh) {
42 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
43 smp_mb__after_atomic();
44 wake_up_bit(&orig_bh->b_state, BH_Shadow);
45 }
46 unlock_buffer(bh);
47}
48
49/*
50 * When an ext4 file is truncated, it is possible that some pages are not
51 * successfully freed, because they are attached to a committing transaction.
52 * After the transaction commits, these pages are left on the LRU, with no
53 * ->mapping, and with attached buffers. These pages are trivially reclaimable
54 * by the VM, but their apparent absence upsets the VM accounting, and it makes
55 * the numbers in /proc/meminfo look odd.
56 *
57 * So here, we have a buffer which has just come off the forget list. Look to
58 * see if we can strip all buffers from the backing page.
59 *
60 * Called under lock_journal(), and possibly under journal_datalist_lock. The
61 * caller provided us with a ref against the buffer, and we drop that here.
62 */
63static void release_buffer_page(struct buffer_head *bh)
64{
65 struct page *page;
66
67 if (buffer_dirty(bh))
68 goto nope;
69 if (atomic_read(&bh->b_count) != 1)
70 goto nope;
71 page = bh->b_page;
72 if (!page)
73 goto nope;
74 if (page->mapping)
75 goto nope;
76
77 /* OK, it's a truncated page */
78 if (!trylock_page(page))
79 goto nope;
80
81 get_page(page);
82 __brelse(bh);
83 try_to_free_buffers(page);
84 unlock_page(page);
85 put_page(page);
86 return;
87
88nope:
89 __brelse(bh);
90}
91
92static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
93{
94 struct commit_header *h;
95 __u32 csum;
96
97 if (!jbd2_journal_has_csum_v2or3(j))
98 return;
99
100 h = (struct commit_header *)(bh->b_data);
101 h->h_chksum_type = 0;
102 h->h_chksum_size = 0;
103 h->h_chksum[0] = 0;
104 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
105 h->h_chksum[0] = cpu_to_be32(csum);
106}
107
108/*
109 * Done it all: now submit the commit record. We should have
110 * cleaned up our previous buffers by now, so if we are in abort
111 * mode we can now just skip the rest of the journal write
112 * entirely.
113 *
114 * Returns 1 if the journal needs to be aborted or 0 on success
115 */
116static int journal_submit_commit_record(journal_t *journal,
117 transaction_t *commit_transaction,
118 struct buffer_head **cbh,
119 __u32 crc32_sum)
120{
121 struct commit_header *tmp;
122 struct buffer_head *bh;
123 int ret;
124 struct timespec64 now = current_kernel_time64();
125
126 *cbh = NULL;
127
128 if (is_journal_aborted(journal))
129 return 0;
130
131 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
132 JBD2_COMMIT_BLOCK);
133 if (!bh)
134 return 1;
135
136 tmp = (struct commit_header *)bh->b_data;
137 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
138 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
139
140 if (jbd2_has_feature_checksum(journal)) {
141 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
142 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
143 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
144 }
145 jbd2_commit_block_csum_set(journal, bh);
146
147 BUFFER_TRACE(bh, "submit commit block");
148 lock_buffer(bh);
149 clear_buffer_dirty(bh);
150 set_buffer_uptodate(bh);
151 bh->b_end_io = journal_end_buffer_io_sync;
152
153 if (journal->j_flags & JBD2_BARRIER &&
154 !jbd2_has_feature_async_commit(journal))
155 ret = submit_bh(REQ_OP_WRITE,
156 REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh);
157 else
158 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
159
160 *cbh = bh;
161 return ret;
162}
163
164/*
165 * This function along with journal_submit_commit_record
166 * allows to write the commit record asynchronously.
167 */
168static int journal_wait_on_commit_record(journal_t *journal,
169 struct buffer_head *bh)
170{
171 int ret = 0;
172
173 clear_buffer_dirty(bh);
174 wait_on_buffer(bh);
175
176 if (unlikely(!buffer_uptodate(bh)))
177 ret = -EIO;
178 put_bh(bh); /* One for getblk() */
179
180 return ret;
181}
182
183/*
184 * write the filemap data using writepage() address_space_operations.
185 * We don't do block allocation here even for delalloc. We don't
186 * use writepages() because with dealyed allocation we may be doing
187 * block allocation in writepages().
188 */
189static int journal_submit_inode_data_buffers(struct address_space *mapping)
190{
191 int ret;
192 struct writeback_control wbc = {
193 .sync_mode = WB_SYNC_ALL,
194 .nr_to_write = mapping->nrpages * 2,
195 .range_start = 0,
196 .range_end = i_size_read(mapping->host),
197 };
198
199 ret = generic_writepages(mapping, &wbc);
200 return ret;
201}
202
203/*
204 * Submit all the data buffers of inode associated with the transaction to
205 * disk.
206 *
207 * We are in a committing transaction. Therefore no new inode can be added to
208 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
209 * operate on from being released while we write out pages.
210 */
211static int journal_submit_data_buffers(journal_t *journal,
212 transaction_t *commit_transaction)
213{
214 struct jbd2_inode *jinode;
215 int err, ret = 0;
216 struct address_space *mapping;
217
218 spin_lock(&journal->j_list_lock);
219 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
220 if (!(jinode->i_flags & JI_WRITE_DATA))
221 continue;
222 mapping = jinode->i_vfs_inode->i_mapping;
223 jinode->i_flags |= JI_COMMIT_RUNNING;
224 spin_unlock(&journal->j_list_lock);
225 /*
226 * submit the inode data buffers. We use writepage
227 * instead of writepages. Because writepages can do
228 * block allocation with delalloc. We need to write
229 * only allocated blocks here.
230 */
231 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
232 err = journal_submit_inode_data_buffers(mapping);
233 if (!ret)
234 ret = err;
235 spin_lock(&journal->j_list_lock);
236 J_ASSERT(jinode->i_transaction == commit_transaction);
237 jinode->i_flags &= ~JI_COMMIT_RUNNING;
238 smp_mb();
239 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
240 }
241 spin_unlock(&journal->j_list_lock);
242 return ret;
243}
244
245/*
246 * Wait for data submitted for writeout, refile inodes to proper
247 * transaction if needed.
248 *
249 */
250static int journal_finish_inode_data_buffers(journal_t *journal,
251 transaction_t *commit_transaction)
252{
253 struct jbd2_inode *jinode, *next_i;
254 int err, ret = 0;
255
256 /* For locking, see the comment in journal_submit_data_buffers() */
257 spin_lock(&journal->j_list_lock);
258 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
259 if (!(jinode->i_flags & JI_WAIT_DATA))
260 continue;
261 jinode->i_flags |= JI_COMMIT_RUNNING;
262 spin_unlock(&journal->j_list_lock);
263 err = filemap_fdatawait_keep_errors(
264 jinode->i_vfs_inode->i_mapping);
265 if (!ret)
266 ret = err;
267 spin_lock(&journal->j_list_lock);
268 jinode->i_flags &= ~JI_COMMIT_RUNNING;
269 smp_mb();
270 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
271 }
272
273 /* Now refile inode to proper lists */
274 list_for_each_entry_safe(jinode, next_i,
275 &commit_transaction->t_inode_list, i_list) {
276 list_del(&jinode->i_list);
277 if (jinode->i_next_transaction) {
278 jinode->i_transaction = jinode->i_next_transaction;
279 jinode->i_next_transaction = NULL;
280 list_add(&jinode->i_list,
281 &jinode->i_transaction->t_inode_list);
282 } else {
283 jinode->i_transaction = NULL;
284 }
285 }
286 spin_unlock(&journal->j_list_lock);
287
288 return ret;
289}
290
291static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
292{
293 struct page *page = bh->b_page;
294 char *addr;
295 __u32 checksum;
296
297 addr = kmap_atomic(page);
298 checksum = crc32_be(crc32_sum,
299 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
300 kunmap_atomic(addr);
301
302 return checksum;
303}
304
305static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
306 unsigned long long block)
307{
308 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
309 if (jbd2_has_feature_64bit(j))
310 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
311}
312
313static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
314 struct buffer_head *bh, __u32 sequence)
315{
316 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
317 struct page *page = bh->b_page;
318 __u8 *addr;
319 __u32 csum32;
320 __be32 seq;
321
322 if (!jbd2_journal_has_csum_v2or3(j))
323 return;
324
325 seq = cpu_to_be32(sequence);
326 addr = kmap_atomic(page);
327 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
328 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
329 bh->b_size);
330 kunmap_atomic(addr);
331
332 if (jbd2_has_feature_csum3(j))
333 tag3->t_checksum = cpu_to_be32(csum32);
334 else
335 tag->t_checksum = cpu_to_be16(csum32);
336}
337/*
338 * jbd2_journal_commit_transaction
339 *
340 * The primary function for committing a transaction to the log. This
341 * function is called by the journal thread to begin a complete commit.
342 */
343void jbd2_journal_commit_transaction(journal_t *journal)
344{
345 struct transaction_stats_s stats;
346 transaction_t *commit_transaction;
347 struct journal_head *jh;
348 struct buffer_head *descriptor;
349 struct buffer_head **wbuf = journal->j_wbuf;
350 int bufs;
351 int flags;
352 int err;
353 unsigned long long blocknr;
354 ktime_t start_time;
355 u64 commit_time;
356 char *tagp = NULL;
357 journal_block_tag_t *tag = NULL;
358 int space_left = 0;
359 int first_tag = 0;
360 int tag_flag;
361 int i;
362 int tag_bytes = journal_tag_bytes(journal);
363 struct buffer_head *cbh = NULL; /* For transactional checksums */
364 __u32 crc32_sum = ~0;
365 struct blk_plug plug;
366 /* Tail of the journal */
367 unsigned long first_block;
368 tid_t first_tid;
369 int update_tail;
370 int csum_size = 0;
371 LIST_HEAD(io_bufs);
372 LIST_HEAD(log_bufs);
373
374 if (jbd2_journal_has_csum_v2or3(journal))
375 csum_size = sizeof(struct jbd2_journal_block_tail);
376
377 /*
378 * First job: lock down the current transaction and wait for
379 * all outstanding updates to complete.
380 */
381
382 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
383 if (journal->j_flags & JBD2_FLUSHED) {
384 jbd_debug(3, "super block updated\n");
385 mutex_lock_io(&journal->j_checkpoint_mutex);
386 /*
387 * We hold j_checkpoint_mutex so tail cannot change under us.
388 * We don't need any special data guarantees for writing sb
389 * since journal is empty and it is ok for write to be
390 * flushed only with transaction commit.
391 */
392 jbd2_journal_update_sb_log_tail(journal,
393 journal->j_tail_sequence,
394 journal->j_tail,
395 REQ_SYNC);
396 mutex_unlock(&journal->j_checkpoint_mutex);
397 } else {
398 jbd_debug(3, "superblock not updated\n");
399 }
400
401 J_ASSERT(journal->j_running_transaction != NULL);
402 J_ASSERT(journal->j_committing_transaction == NULL);
403
404 commit_transaction = journal->j_running_transaction;
405
406 trace_jbd2_start_commit(journal, commit_transaction);
407 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
408 commit_transaction->t_tid);
409
410 write_lock(&journal->j_state_lock);
411 J_ASSERT(commit_transaction->t_state == T_RUNNING);
412 commit_transaction->t_state = T_LOCKED;
413
414 trace_jbd2_commit_locking(journal, commit_transaction);
415 stats.run.rs_wait = commit_transaction->t_max_wait;
416 stats.run.rs_request_delay = 0;
417 stats.run.rs_locked = jiffies;
418 if (commit_transaction->t_requested)
419 stats.run.rs_request_delay =
420 jbd2_time_diff(commit_transaction->t_requested,
421 stats.run.rs_locked);
422 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
423 stats.run.rs_locked);
424
425 spin_lock(&commit_transaction->t_handle_lock);
426 while (atomic_read(&commit_transaction->t_updates)) {
427 DEFINE_WAIT(wait);
428
429 prepare_to_wait(&journal->j_wait_updates, &wait,
430 TASK_UNINTERRUPTIBLE);
431 if (atomic_read(&commit_transaction->t_updates)) {
432 spin_unlock(&commit_transaction->t_handle_lock);
433 write_unlock(&journal->j_state_lock);
434 schedule();
435 write_lock(&journal->j_state_lock);
436 spin_lock(&commit_transaction->t_handle_lock);
437 }
438 finish_wait(&journal->j_wait_updates, &wait);
439 }
440 spin_unlock(&commit_transaction->t_handle_lock);
441
442 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
443 journal->j_max_transaction_buffers);
444
445 /*
446 * First thing we are allowed to do is to discard any remaining
447 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
448 * that there are no such buffers: if a large filesystem
449 * operation like a truncate needs to split itself over multiple
450 * transactions, then it may try to do a jbd2_journal_restart() while
451 * there are still BJ_Reserved buffers outstanding. These must
452 * be released cleanly from the current transaction.
453 *
454 * In this case, the filesystem must still reserve write access
455 * again before modifying the buffer in the new transaction, but
456 * we do not require it to remember exactly which old buffers it
457 * has reserved. This is consistent with the existing behaviour
458 * that multiple jbd2_journal_get_write_access() calls to the same
459 * buffer are perfectly permissible.
460 */
461 while (commit_transaction->t_reserved_list) {
462 jh = commit_transaction->t_reserved_list;
463 JBUFFER_TRACE(jh, "reserved, unused: refile");
464 /*
465 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
466 * leave undo-committed data.
467 */
468 if (jh->b_committed_data) {
469 struct buffer_head *bh = jh2bh(jh);
470
471 jbd_lock_bh_state(bh);
472 jbd2_free(jh->b_committed_data, bh->b_size);
473 jh->b_committed_data = NULL;
474 jbd_unlock_bh_state(bh);
475 }
476 jbd2_journal_refile_buffer(journal, jh);
477 }
478
479 /*
480 * Now try to drop any written-back buffers from the journal's
481 * checkpoint lists. We do this *before* commit because it potentially
482 * frees some memory
483 */
484 spin_lock(&journal->j_list_lock);
485 __jbd2_journal_clean_checkpoint_list(journal, false);
486 spin_unlock(&journal->j_list_lock);
487
488 jbd_debug(3, "JBD2: commit phase 1\n");
489
490 /*
491 * Clear revoked flag to reflect there is no revoked buffers
492 * in the next transaction which is going to be started.
493 */
494 jbd2_clear_buffer_revoked_flags(journal);
495
496 /*
497 * Switch to a new revoke table.
498 */
499 jbd2_journal_switch_revoke_table(journal);
500
501 /*
502 * Reserved credits cannot be claimed anymore, free them
503 */
504 atomic_sub(atomic_read(&journal->j_reserved_credits),
505 &commit_transaction->t_outstanding_credits);
506
507 trace_jbd2_commit_flushing(journal, commit_transaction);
508 stats.run.rs_flushing = jiffies;
509 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
510 stats.run.rs_flushing);
511
512 commit_transaction->t_state = T_FLUSH;
513 journal->j_committing_transaction = commit_transaction;
514 journal->j_running_transaction = NULL;
515 start_time = ktime_get();
516 commit_transaction->t_log_start = journal->j_head;
517 wake_up(&journal->j_wait_transaction_locked);
518 write_unlock(&journal->j_state_lock);
519
520 jbd_debug(3, "JBD2: commit phase 2a\n");
521
522 /*
523 * Now start flushing things to disk, in the order they appear
524 * on the transaction lists. Data blocks go first.
525 */
526 err = journal_submit_data_buffers(journal, commit_transaction);
527 if (err)
528 jbd2_journal_abort(journal, err);
529
530 blk_start_plug(&plug);
531 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
532
533 jbd_debug(3, "JBD2: commit phase 2b\n");
534
535 /*
536 * Way to go: we have now written out all of the data for a
537 * transaction! Now comes the tricky part: we need to write out
538 * metadata. Loop over the transaction's entire buffer list:
539 */
540 write_lock(&journal->j_state_lock);
541 commit_transaction->t_state = T_COMMIT;
542 write_unlock(&journal->j_state_lock);
543
544 trace_jbd2_commit_logging(journal, commit_transaction);
545 stats.run.rs_logging = jiffies;
546 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
547 stats.run.rs_logging);
548 stats.run.rs_blocks =
549 atomic_read(&commit_transaction->t_outstanding_credits);
550 stats.run.rs_blocks_logged = 0;
551
552 J_ASSERT(commit_transaction->t_nr_buffers <=
553 atomic_read(&commit_transaction->t_outstanding_credits));
554
555 err = 0;
556 bufs = 0;
557 descriptor = NULL;
558 while (commit_transaction->t_buffers) {
559
560 /* Find the next buffer to be journaled... */
561
562 jh = commit_transaction->t_buffers;
563
564 /* If we're in abort mode, we just un-journal the buffer and
565 release it. */
566
567 if (is_journal_aborted(journal)) {
568 clear_buffer_jbddirty(jh2bh(jh));
569 JBUFFER_TRACE(jh, "journal is aborting: refile");
570 jbd2_buffer_abort_trigger(jh,
571 jh->b_frozen_data ?
572 jh->b_frozen_triggers :
573 jh->b_triggers);
574 jbd2_journal_refile_buffer(journal, jh);
575 /* If that was the last one, we need to clean up
576 * any descriptor buffers which may have been
577 * already allocated, even if we are now
578 * aborting. */
579 if (!commit_transaction->t_buffers)
580 goto start_journal_io;
581 continue;
582 }
583
584 /* Make sure we have a descriptor block in which to
585 record the metadata buffer. */
586
587 if (!descriptor) {
588 J_ASSERT (bufs == 0);
589
590 jbd_debug(4, "JBD2: get descriptor\n");
591
592 descriptor = jbd2_journal_get_descriptor_buffer(
593 commit_transaction,
594 JBD2_DESCRIPTOR_BLOCK);
595 if (!descriptor) {
596 jbd2_journal_abort(journal, -EIO);
597 continue;
598 }
599
600 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
601 (unsigned long long)descriptor->b_blocknr,
602 descriptor->b_data);
603 tagp = &descriptor->b_data[sizeof(journal_header_t)];
604 space_left = descriptor->b_size -
605 sizeof(journal_header_t);
606 first_tag = 1;
607 set_buffer_jwrite(descriptor);
608 set_buffer_dirty(descriptor);
609 wbuf[bufs++] = descriptor;
610
611 /* Record it so that we can wait for IO
612 completion later */
613 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
614 jbd2_file_log_bh(&log_bufs, descriptor);
615 }
616
617 /* Where is the buffer to be written? */
618
619 err = jbd2_journal_next_log_block(journal, &blocknr);
620 /* If the block mapping failed, just abandon the buffer
621 and repeat this loop: we'll fall into the
622 refile-on-abort condition above. */
623 if (err) {
624 jbd2_journal_abort(journal, err);
625 continue;
626 }
627
628 /*
629 * start_this_handle() uses t_outstanding_credits to determine
630 * the free space in the log, but this counter is changed
631 * by jbd2_journal_next_log_block() also.
632 */
633 atomic_dec(&commit_transaction->t_outstanding_credits);
634
635 /* Bump b_count to prevent truncate from stumbling over
636 the shadowed buffer! @@@ This can go if we ever get
637 rid of the shadow pairing of buffers. */
638 atomic_inc(&jh2bh(jh)->b_count);
639
640 /*
641 * Make a temporary IO buffer with which to write it out
642 * (this will requeue the metadata buffer to BJ_Shadow).
643 */
644 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
645 JBUFFER_TRACE(jh, "ph3: write metadata");
646 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
647 jh, &wbuf[bufs], blocknr);
648 if (flags < 0) {
649 jbd2_journal_abort(journal, flags);
650 continue;
651 }
652 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
653
654 /* Record the new block's tag in the current descriptor
655 buffer */
656
657 tag_flag = 0;
658 if (flags & 1)
659 tag_flag |= JBD2_FLAG_ESCAPE;
660 if (!first_tag)
661 tag_flag |= JBD2_FLAG_SAME_UUID;
662
663 tag = (journal_block_tag_t *) tagp;
664 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
665 tag->t_flags = cpu_to_be16(tag_flag);
666 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
667 commit_transaction->t_tid);
668 tagp += tag_bytes;
669 space_left -= tag_bytes;
670 bufs++;
671
672 if (first_tag) {
673 memcpy (tagp, journal->j_uuid, 16);
674 tagp += 16;
675 space_left -= 16;
676 first_tag = 0;
677 }
678
679 /* If there's no more to do, or if the descriptor is full,
680 let the IO rip! */
681
682 if (bufs == journal->j_wbufsize ||
683 commit_transaction->t_buffers == NULL ||
684 space_left < tag_bytes + 16 + csum_size) {
685
686 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
687
688 /* Write an end-of-descriptor marker before
689 submitting the IOs. "tag" still points to
690 the last tag we set up. */
691
692 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
693
694 jbd2_descriptor_block_csum_set(journal, descriptor);
695start_journal_io:
696 for (i = 0; i < bufs; i++) {
697 struct buffer_head *bh = wbuf[i];
698 /*
699 * Compute checksum.
700 */
701 if (jbd2_has_feature_checksum(journal)) {
702 crc32_sum =
703 jbd2_checksum_data(crc32_sum, bh);
704 }
705
706 lock_buffer(bh);
707 clear_buffer_dirty(bh);
708 set_buffer_uptodate(bh);
709 bh->b_end_io = journal_end_buffer_io_sync;
710 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
711 }
712 cond_resched();
713 stats.run.rs_blocks_logged += bufs;
714
715 /* Force a new descriptor to be generated next
716 time round the loop. */
717 descriptor = NULL;
718 bufs = 0;
719 }
720 }
721
722 err = journal_finish_inode_data_buffers(journal, commit_transaction);
723 if (err) {
724 printk(KERN_WARNING
725 "JBD2: Detected IO errors while flushing file data "
726 "on %s\n", journal->j_devname);
727 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
728 jbd2_journal_abort(journal, err);
729 err = 0;
730 }
731
732 /*
733 * Get current oldest transaction in the log before we issue flush
734 * to the filesystem device. After the flush we can be sure that
735 * blocks of all older transactions are checkpointed to persistent
736 * storage and we will be safe to update journal start in the
737 * superblock with the numbers we get here.
738 */
739 update_tail =
740 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
741
742 write_lock(&journal->j_state_lock);
743 if (update_tail) {
744 long freed = first_block - journal->j_tail;
745
746 if (first_block < journal->j_tail)
747 freed += journal->j_last - journal->j_first;
748 /* Update tail only if we free significant amount of space */
749 if (freed < journal->j_maxlen / 4)
750 update_tail = 0;
751 }
752 J_ASSERT(commit_transaction->t_state == T_COMMIT);
753 commit_transaction->t_state = T_COMMIT_DFLUSH;
754 write_unlock(&journal->j_state_lock);
755
756 /*
757 * If the journal is not located on the file system device,
758 * then we must flush the file system device before we issue
759 * the commit record
760 */
761 if (commit_transaction->t_need_data_flush &&
762 (journal->j_fs_dev != journal->j_dev) &&
763 (journal->j_flags & JBD2_BARRIER))
764 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
765
766 /* Done it all: now write the commit record asynchronously. */
767 if (jbd2_has_feature_async_commit(journal)) {
768 err = journal_submit_commit_record(journal, commit_transaction,
769 &cbh, crc32_sum);
770 if (err)
771 __jbd2_journal_abort_hard(journal);
772 }
773
774 blk_finish_plug(&plug);
775
776 /* Lo and behold: we have just managed to send a transaction to
777 the log. Before we can commit it, wait for the IO so far to
778 complete. Control buffers being written are on the
779 transaction's t_log_list queue, and metadata buffers are on
780 the io_bufs list.
781
782 Wait for the buffers in reverse order. That way we are
783 less likely to be woken up until all IOs have completed, and
784 so we incur less scheduling load.
785 */
786
787 jbd_debug(3, "JBD2: commit phase 3\n");
788
789 while (!list_empty(&io_bufs)) {
790 struct buffer_head *bh = list_entry(io_bufs.prev,
791 struct buffer_head,
792 b_assoc_buffers);
793
794 wait_on_buffer(bh);
795 cond_resched();
796
797 if (unlikely(!buffer_uptodate(bh)))
798 err = -EIO;
799 jbd2_unfile_log_bh(bh);
800
801 /*
802 * The list contains temporary buffer heads created by
803 * jbd2_journal_write_metadata_buffer().
804 */
805 BUFFER_TRACE(bh, "dumping temporary bh");
806 __brelse(bh);
807 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
808 free_buffer_head(bh);
809
810 /* We also have to refile the corresponding shadowed buffer */
811 jh = commit_transaction->t_shadow_list->b_tprev;
812 bh = jh2bh(jh);
813 clear_buffer_jwrite(bh);
814 J_ASSERT_BH(bh, buffer_jbddirty(bh));
815 J_ASSERT_BH(bh, !buffer_shadow(bh));
816
817 /* The metadata is now released for reuse, but we need
818 to remember it against this transaction so that when
819 we finally commit, we can do any checkpointing
820 required. */
821 JBUFFER_TRACE(jh, "file as BJ_Forget");
822 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
823 JBUFFER_TRACE(jh, "brelse shadowed buffer");
824 __brelse(bh);
825 }
826
827 J_ASSERT (commit_transaction->t_shadow_list == NULL);
828
829 jbd_debug(3, "JBD2: commit phase 4\n");
830
831 /* Here we wait for the revoke record and descriptor record buffers */
832 while (!list_empty(&log_bufs)) {
833 struct buffer_head *bh;
834
835 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
836 wait_on_buffer(bh);
837 cond_resched();
838
839 if (unlikely(!buffer_uptodate(bh)))
840 err = -EIO;
841
842 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
843 clear_buffer_jwrite(bh);
844 jbd2_unfile_log_bh(bh);
845 __brelse(bh); /* One for getblk */
846 /* AKPM: bforget here */
847 }
848
849 if (err)
850 jbd2_journal_abort(journal, err);
851
852 jbd_debug(3, "JBD2: commit phase 5\n");
853 write_lock(&journal->j_state_lock);
854 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
855 commit_transaction->t_state = T_COMMIT_JFLUSH;
856 write_unlock(&journal->j_state_lock);
857
858 if (!jbd2_has_feature_async_commit(journal)) {
859 err = journal_submit_commit_record(journal, commit_transaction,
860 &cbh, crc32_sum);
861 if (err)
862 __jbd2_journal_abort_hard(journal);
863 }
864 if (cbh)
865 err = journal_wait_on_commit_record(journal, cbh);
866 if (jbd2_has_feature_async_commit(journal) &&
867 journal->j_flags & JBD2_BARRIER) {
868 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
869 }
870
871 if (err)
872 jbd2_journal_abort(journal, err);
873
874 /*
875 * Now disk caches for filesystem device are flushed so we are safe to
876 * erase checkpointed transactions from the log by updating journal
877 * superblock.
878 */
879 if (update_tail)
880 jbd2_update_log_tail(journal, first_tid, first_block);
881
882 /* End of a transaction! Finally, we can do checkpoint
883 processing: any buffers committed as a result of this
884 transaction can be removed from any checkpoint list it was on
885 before. */
886
887 jbd_debug(3, "JBD2: commit phase 6\n");
888
889 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
890 J_ASSERT(commit_transaction->t_buffers == NULL);
891 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
892 J_ASSERT(commit_transaction->t_shadow_list == NULL);
893
894restart_loop:
895 /*
896 * As there are other places (journal_unmap_buffer()) adding buffers
897 * to this list we have to be careful and hold the j_list_lock.
898 */
899 spin_lock(&journal->j_list_lock);
900 while (commit_transaction->t_forget) {
901 transaction_t *cp_transaction;
902 struct buffer_head *bh;
903 int try_to_free = 0;
904
905 jh = commit_transaction->t_forget;
906 spin_unlock(&journal->j_list_lock);
907 bh = jh2bh(jh);
908 /*
909 * Get a reference so that bh cannot be freed before we are
910 * done with it.
911 */
912 get_bh(bh);
913 jbd_lock_bh_state(bh);
914 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
915
916 /*
917 * If there is undo-protected committed data against
918 * this buffer, then we can remove it now. If it is a
919 * buffer needing such protection, the old frozen_data
920 * field now points to a committed version of the
921 * buffer, so rotate that field to the new committed
922 * data.
923 *
924 * Otherwise, we can just throw away the frozen data now.
925 *
926 * We also know that the frozen data has already fired
927 * its triggers if they exist, so we can clear that too.
928 */
929 if (jh->b_committed_data) {
930 jbd2_free(jh->b_committed_data, bh->b_size);
931 jh->b_committed_data = NULL;
932 if (jh->b_frozen_data) {
933 jh->b_committed_data = jh->b_frozen_data;
934 jh->b_frozen_data = NULL;
935 jh->b_frozen_triggers = NULL;
936 }
937 } else if (jh->b_frozen_data) {
938 jbd2_free(jh->b_frozen_data, bh->b_size);
939 jh->b_frozen_data = NULL;
940 jh->b_frozen_triggers = NULL;
941 }
942
943 spin_lock(&journal->j_list_lock);
944 cp_transaction = jh->b_cp_transaction;
945 if (cp_transaction) {
946 JBUFFER_TRACE(jh, "remove from old cp transaction");
947 cp_transaction->t_chp_stats.cs_dropped++;
948 __jbd2_journal_remove_checkpoint(jh);
949 }
950
951 /* Only re-checkpoint the buffer_head if it is marked
952 * dirty. If the buffer was added to the BJ_Forget list
953 * by jbd2_journal_forget, it may no longer be dirty and
954 * there's no point in keeping a checkpoint record for
955 * it. */
956
957 /*
958 * A buffer which has been freed while still being journaled by
959 * a previous transaction.
960 */
961 if (buffer_freed(bh)) {
962 /*
963 * If the running transaction is the one containing
964 * "add to orphan" operation (b_next_transaction !=
965 * NULL), we have to wait for that transaction to
966 * commit before we can really get rid of the buffer.
967 * So just clear b_modified to not confuse transaction
968 * credit accounting and refile the buffer to
969 * BJ_Forget of the running transaction. If the just
970 * committed transaction contains "add to orphan"
971 * operation, we can completely invalidate the buffer
972 * now. We are rather through in that since the
973 * buffer may be still accessible when blocksize <
974 * pagesize and it is attached to the last partial
975 * page.
976 */
977 jh->b_modified = 0;
978 if (!jh->b_next_transaction) {
979 clear_buffer_freed(bh);
980 clear_buffer_jbddirty(bh);
981 clear_buffer_mapped(bh);
982 clear_buffer_new(bh);
983 clear_buffer_req(bh);
984 bh->b_bdev = NULL;
985 }
986 }
987
988 if (buffer_jbddirty(bh)) {
989 JBUFFER_TRACE(jh, "add to new checkpointing trans");
990 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
991 if (is_journal_aborted(journal))
992 clear_buffer_jbddirty(bh);
993 } else {
994 J_ASSERT_BH(bh, !buffer_dirty(bh));
995 /*
996 * The buffer on BJ_Forget list and not jbddirty means
997 * it has been freed by this transaction and hence it
998 * could not have been reallocated until this
999 * transaction has committed. *BUT* it could be
1000 * reallocated once we have written all the data to
1001 * disk and before we process the buffer on BJ_Forget
1002 * list.
1003 */
1004 if (!jh->b_next_transaction)
1005 try_to_free = 1;
1006 }
1007 JBUFFER_TRACE(jh, "refile or unfile buffer");
1008 __jbd2_journal_refile_buffer(jh);
1009 jbd_unlock_bh_state(bh);
1010 if (try_to_free)
1011 release_buffer_page(bh); /* Drops bh reference */
1012 else
1013 __brelse(bh);
1014 cond_resched_lock(&journal->j_list_lock);
1015 }
1016 spin_unlock(&journal->j_list_lock);
1017 /*
1018 * This is a bit sleazy. We use j_list_lock to protect transition
1019 * of a transaction into T_FINISHED state and calling
1020 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1021 * other checkpointing code processing the transaction...
1022 */
1023 write_lock(&journal->j_state_lock);
1024 spin_lock(&journal->j_list_lock);
1025 /*
1026 * Now recheck if some buffers did not get attached to the transaction
1027 * while the lock was dropped...
1028 */
1029 if (commit_transaction->t_forget) {
1030 spin_unlock(&journal->j_list_lock);
1031 write_unlock(&journal->j_state_lock);
1032 goto restart_loop;
1033 }
1034
1035 /* Add the transaction to the checkpoint list
1036 * __journal_remove_checkpoint() can not destroy transaction
1037 * under us because it is not marked as T_FINISHED yet */
1038 if (journal->j_checkpoint_transactions == NULL) {
1039 journal->j_checkpoint_transactions = commit_transaction;
1040 commit_transaction->t_cpnext = commit_transaction;
1041 commit_transaction->t_cpprev = commit_transaction;
1042 } else {
1043 commit_transaction->t_cpnext =
1044 journal->j_checkpoint_transactions;
1045 commit_transaction->t_cpprev =
1046 commit_transaction->t_cpnext->t_cpprev;
1047 commit_transaction->t_cpnext->t_cpprev =
1048 commit_transaction;
1049 commit_transaction->t_cpprev->t_cpnext =
1050 commit_transaction;
1051 }
1052 spin_unlock(&journal->j_list_lock);
1053
1054 /* Done with this transaction! */
1055
1056 jbd_debug(3, "JBD2: commit phase 7\n");
1057
1058 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1059
1060 commit_transaction->t_start = jiffies;
1061 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1062 commit_transaction->t_start);
1063
1064 /*
1065 * File the transaction statistics
1066 */
1067 stats.ts_tid = commit_transaction->t_tid;
1068 stats.run.rs_handle_count =
1069 atomic_read(&commit_transaction->t_handle_count);
1070 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1071 commit_transaction->t_tid, &stats.run);
1072 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1073
1074 commit_transaction->t_state = T_COMMIT_CALLBACK;
1075 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1076 journal->j_commit_sequence = commit_transaction->t_tid;
1077 journal->j_committing_transaction = NULL;
1078 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1079
1080 /*
1081 * weight the commit time higher than the average time so we don't
1082 * react too strongly to vast changes in the commit time
1083 */
1084 if (likely(journal->j_average_commit_time))
1085 journal->j_average_commit_time = (commit_time +
1086 journal->j_average_commit_time*3) / 4;
1087 else
1088 journal->j_average_commit_time = commit_time;
1089
1090 write_unlock(&journal->j_state_lock);
1091
1092 if (journal->j_commit_callback)
1093 journal->j_commit_callback(journal, commit_transaction);
1094
1095 trace_jbd2_end_commit(journal, commit_transaction);
1096 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1097 journal->j_commit_sequence, journal->j_tail_sequence);
1098
1099 write_lock(&journal->j_state_lock);
1100 spin_lock(&journal->j_list_lock);
1101 commit_transaction->t_state = T_FINISHED;
1102 /* Check if the transaction can be dropped now that we are finished */
1103 if (commit_transaction->t_checkpoint_list == NULL &&
1104 commit_transaction->t_checkpoint_io_list == NULL) {
1105 __jbd2_journal_drop_transaction(journal, commit_transaction);
1106 jbd2_journal_free_transaction(commit_transaction);
1107 }
1108 spin_unlock(&journal->j_list_lock);
1109 write_unlock(&journal->j_state_lock);
1110 wake_up(&journal->j_wait_done_commit);
1111
1112 /*
1113 * Calculate overall stats
1114 */
1115 spin_lock(&journal->j_history_lock);
1116 journal->j_stats.ts_tid++;
1117 journal->j_stats.ts_requested += stats.ts_requested;
1118 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1119 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1120 journal->j_stats.run.rs_running += stats.run.rs_running;
1121 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1122 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1123 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1124 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1125 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1126 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1127 spin_unlock(&journal->j_history_lock);
1128}
1/*
2 * linux/fs/jbd2/commit.c
3 *
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/jbd2.h>
19#include <linux/errno.h>
20#include <linux/slab.h>
21#include <linux/mm.h>
22#include <linux/pagemap.h>
23#include <linux/jiffies.h>
24#include <linux/crc32.h>
25#include <linux/writeback.h>
26#include <linux/backing-dev.h>
27#include <linux/bio.h>
28#include <linux/blkdev.h>
29#include <linux/bitops.h>
30#include <trace/events/jbd2.h>
31
32/*
33 * Default IO end handler for temporary BJ_IO buffer_heads.
34 */
35static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
36{
37 BUFFER_TRACE(bh, "");
38 if (uptodate)
39 set_buffer_uptodate(bh);
40 else
41 clear_buffer_uptodate(bh);
42 unlock_buffer(bh);
43}
44
45/*
46 * When an ext4 file is truncated, it is possible that some pages are not
47 * successfully freed, because they are attached to a committing transaction.
48 * After the transaction commits, these pages are left on the LRU, with no
49 * ->mapping, and with attached buffers. These pages are trivially reclaimable
50 * by the VM, but their apparent absence upsets the VM accounting, and it makes
51 * the numbers in /proc/meminfo look odd.
52 *
53 * So here, we have a buffer which has just come off the forget list. Look to
54 * see if we can strip all buffers from the backing page.
55 *
56 * Called under lock_journal(), and possibly under journal_datalist_lock. The
57 * caller provided us with a ref against the buffer, and we drop that here.
58 */
59static void release_buffer_page(struct buffer_head *bh)
60{
61 struct page *page;
62
63 if (buffer_dirty(bh))
64 goto nope;
65 if (atomic_read(&bh->b_count) != 1)
66 goto nope;
67 page = bh->b_page;
68 if (!page)
69 goto nope;
70 if (page->mapping)
71 goto nope;
72
73 /* OK, it's a truncated page */
74 if (!trylock_page(page))
75 goto nope;
76
77 page_cache_get(page);
78 __brelse(bh);
79 try_to_free_buffers(page);
80 unlock_page(page);
81 page_cache_release(page);
82 return;
83
84nope:
85 __brelse(bh);
86}
87
88static void jbd2_commit_block_csum_set(journal_t *j,
89 struct journal_head *descriptor)
90{
91 struct commit_header *h;
92 __u32 csum;
93
94 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
95 return;
96
97 h = (struct commit_header *)(jh2bh(descriptor)->b_data);
98 h->h_chksum_type = 0;
99 h->h_chksum_size = 0;
100 h->h_chksum[0] = 0;
101 csum = jbd2_chksum(j, j->j_csum_seed, jh2bh(descriptor)->b_data,
102 j->j_blocksize);
103 h->h_chksum[0] = cpu_to_be32(csum);
104}
105
106/*
107 * Done it all: now submit the commit record. We should have
108 * cleaned up our previous buffers by now, so if we are in abort
109 * mode we can now just skip the rest of the journal write
110 * entirely.
111 *
112 * Returns 1 if the journal needs to be aborted or 0 on success
113 */
114static int journal_submit_commit_record(journal_t *journal,
115 transaction_t *commit_transaction,
116 struct buffer_head **cbh,
117 __u32 crc32_sum)
118{
119 struct journal_head *descriptor;
120 struct commit_header *tmp;
121 struct buffer_head *bh;
122 int ret;
123 struct timespec now = current_kernel_time();
124
125 *cbh = NULL;
126
127 if (is_journal_aborted(journal))
128 return 0;
129
130 descriptor = jbd2_journal_get_descriptor_buffer(journal);
131 if (!descriptor)
132 return 1;
133
134 bh = jh2bh(descriptor);
135
136 tmp = (struct commit_header *)bh->b_data;
137 tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
138 tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK);
139 tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
140 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
141 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
142
143 if (JBD2_HAS_COMPAT_FEATURE(journal,
144 JBD2_FEATURE_COMPAT_CHECKSUM)) {
145 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
146 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
147 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
148 }
149 jbd2_commit_block_csum_set(journal, descriptor);
150
151 JBUFFER_TRACE(descriptor, "submit commit block");
152 lock_buffer(bh);
153 clear_buffer_dirty(bh);
154 set_buffer_uptodate(bh);
155 bh->b_end_io = journal_end_buffer_io_sync;
156
157 if (journal->j_flags & JBD2_BARRIER &&
158 !JBD2_HAS_INCOMPAT_FEATURE(journal,
159 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT))
160 ret = submit_bh(WRITE_SYNC | WRITE_FLUSH_FUA, bh);
161 else
162 ret = submit_bh(WRITE_SYNC, bh);
163
164 *cbh = bh;
165 return ret;
166}
167
168/*
169 * This function along with journal_submit_commit_record
170 * allows to write the commit record asynchronously.
171 */
172static int journal_wait_on_commit_record(journal_t *journal,
173 struct buffer_head *bh)
174{
175 int ret = 0;
176
177 clear_buffer_dirty(bh);
178 wait_on_buffer(bh);
179
180 if (unlikely(!buffer_uptodate(bh)))
181 ret = -EIO;
182 put_bh(bh); /* One for getblk() */
183 jbd2_journal_put_journal_head(bh2jh(bh));
184
185 return ret;
186}
187
188/*
189 * write the filemap data using writepage() address_space_operations.
190 * We don't do block allocation here even for delalloc. We don't
191 * use writepages() because with dealyed allocation we may be doing
192 * block allocation in writepages().
193 */
194static int journal_submit_inode_data_buffers(struct address_space *mapping)
195{
196 int ret;
197 struct writeback_control wbc = {
198 .sync_mode = WB_SYNC_ALL,
199 .nr_to_write = mapping->nrpages * 2,
200 .range_start = 0,
201 .range_end = i_size_read(mapping->host),
202 };
203
204 ret = generic_writepages(mapping, &wbc);
205 return ret;
206}
207
208/*
209 * Submit all the data buffers of inode associated with the transaction to
210 * disk.
211 *
212 * We are in a committing transaction. Therefore no new inode can be added to
213 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
214 * operate on from being released while we write out pages.
215 */
216static int journal_submit_data_buffers(journal_t *journal,
217 transaction_t *commit_transaction)
218{
219 struct jbd2_inode *jinode;
220 int err, ret = 0;
221 struct address_space *mapping;
222
223 spin_lock(&journal->j_list_lock);
224 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
225 mapping = jinode->i_vfs_inode->i_mapping;
226 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
227 spin_unlock(&journal->j_list_lock);
228 /*
229 * submit the inode data buffers. We use writepage
230 * instead of writepages. Because writepages can do
231 * block allocation with delalloc. We need to write
232 * only allocated blocks here.
233 */
234 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
235 err = journal_submit_inode_data_buffers(mapping);
236 if (!ret)
237 ret = err;
238 spin_lock(&journal->j_list_lock);
239 J_ASSERT(jinode->i_transaction == commit_transaction);
240 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
241 smp_mb__after_clear_bit();
242 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
243 }
244 spin_unlock(&journal->j_list_lock);
245 return ret;
246}
247
248/*
249 * Wait for data submitted for writeout, refile inodes to proper
250 * transaction if needed.
251 *
252 */
253static int journal_finish_inode_data_buffers(journal_t *journal,
254 transaction_t *commit_transaction)
255{
256 struct jbd2_inode *jinode, *next_i;
257 int err, ret = 0;
258
259 /* For locking, see the comment in journal_submit_data_buffers() */
260 spin_lock(&journal->j_list_lock);
261 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
262 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
263 spin_unlock(&journal->j_list_lock);
264 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
265 if (err) {
266 /*
267 * Because AS_EIO is cleared by
268 * filemap_fdatawait_range(), set it again so
269 * that user process can get -EIO from fsync().
270 */
271 set_bit(AS_EIO,
272 &jinode->i_vfs_inode->i_mapping->flags);
273
274 if (!ret)
275 ret = err;
276 }
277 spin_lock(&journal->j_list_lock);
278 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
279 smp_mb__after_clear_bit();
280 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
281 }
282
283 /* Now refile inode to proper lists */
284 list_for_each_entry_safe(jinode, next_i,
285 &commit_transaction->t_inode_list, i_list) {
286 list_del(&jinode->i_list);
287 if (jinode->i_next_transaction) {
288 jinode->i_transaction = jinode->i_next_transaction;
289 jinode->i_next_transaction = NULL;
290 list_add(&jinode->i_list,
291 &jinode->i_transaction->t_inode_list);
292 } else {
293 jinode->i_transaction = NULL;
294 }
295 }
296 spin_unlock(&journal->j_list_lock);
297
298 return ret;
299}
300
301static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
302{
303 struct page *page = bh->b_page;
304 char *addr;
305 __u32 checksum;
306
307 addr = kmap_atomic(page);
308 checksum = crc32_be(crc32_sum,
309 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
310 kunmap_atomic(addr);
311
312 return checksum;
313}
314
315static void write_tag_block(int tag_bytes, journal_block_tag_t *tag,
316 unsigned long long block)
317{
318 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
319 if (tag_bytes > JBD2_TAG_SIZE32)
320 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
321}
322
323static void jbd2_descr_block_csum_set(journal_t *j,
324 struct journal_head *descriptor)
325{
326 struct jbd2_journal_block_tail *tail;
327 __u32 csum;
328
329 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
330 return;
331
332 tail = (struct jbd2_journal_block_tail *)
333 (jh2bh(descriptor)->b_data + j->j_blocksize -
334 sizeof(struct jbd2_journal_block_tail));
335 tail->t_checksum = 0;
336 csum = jbd2_chksum(j, j->j_csum_seed, jh2bh(descriptor)->b_data,
337 j->j_blocksize);
338 tail->t_checksum = cpu_to_be32(csum);
339}
340
341static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
342 struct buffer_head *bh, __u32 sequence)
343{
344 struct page *page = bh->b_page;
345 __u8 *addr;
346 __u32 csum;
347
348 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
349 return;
350
351 sequence = cpu_to_be32(sequence);
352 addr = kmap_atomic(page, KM_USER0);
353 csum = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&sequence,
354 sizeof(sequence));
355 csum = jbd2_chksum(j, csum, addr + offset_in_page(bh->b_data),
356 bh->b_size);
357 kunmap_atomic(addr, KM_USER0);
358
359 tag->t_checksum = cpu_to_be32(csum);
360}
361/*
362 * jbd2_journal_commit_transaction
363 *
364 * The primary function for committing a transaction to the log. This
365 * function is called by the journal thread to begin a complete commit.
366 */
367void jbd2_journal_commit_transaction(journal_t *journal)
368{
369 struct transaction_stats_s stats;
370 transaction_t *commit_transaction;
371 struct journal_head *jh, *new_jh, *descriptor;
372 struct buffer_head **wbuf = journal->j_wbuf;
373 int bufs;
374 int flags;
375 int err;
376 unsigned long long blocknr;
377 ktime_t start_time;
378 u64 commit_time;
379 char *tagp = NULL;
380 journal_header_t *header;
381 journal_block_tag_t *tag = NULL;
382 int space_left = 0;
383 int first_tag = 0;
384 int tag_flag;
385 int i, to_free = 0;
386 int tag_bytes = journal_tag_bytes(journal);
387 struct buffer_head *cbh = NULL; /* For transactional checksums */
388 __u32 crc32_sum = ~0;
389 struct blk_plug plug;
390 /* Tail of the journal */
391 unsigned long first_block;
392 tid_t first_tid;
393 int update_tail;
394 int csum_size = 0;
395
396 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
397 csum_size = sizeof(struct jbd2_journal_block_tail);
398
399 /*
400 * First job: lock down the current transaction and wait for
401 * all outstanding updates to complete.
402 */
403
404 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
405 if (journal->j_flags & JBD2_FLUSHED) {
406 jbd_debug(3, "super block updated\n");
407 mutex_lock(&journal->j_checkpoint_mutex);
408 /*
409 * We hold j_checkpoint_mutex so tail cannot change under us.
410 * We don't need any special data guarantees for writing sb
411 * since journal is empty and it is ok for write to be
412 * flushed only with transaction commit.
413 */
414 jbd2_journal_update_sb_log_tail(journal,
415 journal->j_tail_sequence,
416 journal->j_tail,
417 WRITE_SYNC);
418 mutex_unlock(&journal->j_checkpoint_mutex);
419 } else {
420 jbd_debug(3, "superblock not updated\n");
421 }
422
423 J_ASSERT(journal->j_running_transaction != NULL);
424 J_ASSERT(journal->j_committing_transaction == NULL);
425
426 commit_transaction = journal->j_running_transaction;
427 J_ASSERT(commit_transaction->t_state == T_RUNNING);
428
429 trace_jbd2_start_commit(journal, commit_transaction);
430 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
431 commit_transaction->t_tid);
432
433 write_lock(&journal->j_state_lock);
434 commit_transaction->t_state = T_LOCKED;
435
436 trace_jbd2_commit_locking(journal, commit_transaction);
437 stats.run.rs_wait = commit_transaction->t_max_wait;
438 stats.run.rs_locked = jiffies;
439 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
440 stats.run.rs_locked);
441
442 spin_lock(&commit_transaction->t_handle_lock);
443 while (atomic_read(&commit_transaction->t_updates)) {
444 DEFINE_WAIT(wait);
445
446 prepare_to_wait(&journal->j_wait_updates, &wait,
447 TASK_UNINTERRUPTIBLE);
448 if (atomic_read(&commit_transaction->t_updates)) {
449 spin_unlock(&commit_transaction->t_handle_lock);
450 write_unlock(&journal->j_state_lock);
451 schedule();
452 write_lock(&journal->j_state_lock);
453 spin_lock(&commit_transaction->t_handle_lock);
454 }
455 finish_wait(&journal->j_wait_updates, &wait);
456 }
457 spin_unlock(&commit_transaction->t_handle_lock);
458
459 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
460 journal->j_max_transaction_buffers);
461
462 /*
463 * First thing we are allowed to do is to discard any remaining
464 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
465 * that there are no such buffers: if a large filesystem
466 * operation like a truncate needs to split itself over multiple
467 * transactions, then it may try to do a jbd2_journal_restart() while
468 * there are still BJ_Reserved buffers outstanding. These must
469 * be released cleanly from the current transaction.
470 *
471 * In this case, the filesystem must still reserve write access
472 * again before modifying the buffer in the new transaction, but
473 * we do not require it to remember exactly which old buffers it
474 * has reserved. This is consistent with the existing behaviour
475 * that multiple jbd2_journal_get_write_access() calls to the same
476 * buffer are perfectly permissible.
477 */
478 while (commit_transaction->t_reserved_list) {
479 jh = commit_transaction->t_reserved_list;
480 JBUFFER_TRACE(jh, "reserved, unused: refile");
481 /*
482 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
483 * leave undo-committed data.
484 */
485 if (jh->b_committed_data) {
486 struct buffer_head *bh = jh2bh(jh);
487
488 jbd_lock_bh_state(bh);
489 jbd2_free(jh->b_committed_data, bh->b_size);
490 jh->b_committed_data = NULL;
491 jbd_unlock_bh_state(bh);
492 }
493 jbd2_journal_refile_buffer(journal, jh);
494 }
495
496 /*
497 * Now try to drop any written-back buffers from the journal's
498 * checkpoint lists. We do this *before* commit because it potentially
499 * frees some memory
500 */
501 spin_lock(&journal->j_list_lock);
502 __jbd2_journal_clean_checkpoint_list(journal);
503 spin_unlock(&journal->j_list_lock);
504
505 jbd_debug(3, "JBD2: commit phase 1\n");
506
507 /*
508 * Clear revoked flag to reflect there is no revoked buffers
509 * in the next transaction which is going to be started.
510 */
511 jbd2_clear_buffer_revoked_flags(journal);
512
513 /*
514 * Switch to a new revoke table.
515 */
516 jbd2_journal_switch_revoke_table(journal);
517
518 trace_jbd2_commit_flushing(journal, commit_transaction);
519 stats.run.rs_flushing = jiffies;
520 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
521 stats.run.rs_flushing);
522
523 commit_transaction->t_state = T_FLUSH;
524 journal->j_committing_transaction = commit_transaction;
525 journal->j_running_transaction = NULL;
526 start_time = ktime_get();
527 commit_transaction->t_log_start = journal->j_head;
528 wake_up(&journal->j_wait_transaction_locked);
529 write_unlock(&journal->j_state_lock);
530
531 jbd_debug(3, "JBD2: commit phase 2\n");
532
533 /*
534 * Now start flushing things to disk, in the order they appear
535 * on the transaction lists. Data blocks go first.
536 */
537 err = journal_submit_data_buffers(journal, commit_transaction);
538 if (err)
539 jbd2_journal_abort(journal, err);
540
541 blk_start_plug(&plug);
542 jbd2_journal_write_revoke_records(journal, commit_transaction,
543 WRITE_SYNC);
544 blk_finish_plug(&plug);
545
546 jbd_debug(3, "JBD2: commit phase 2\n");
547
548 /*
549 * Way to go: we have now written out all of the data for a
550 * transaction! Now comes the tricky part: we need to write out
551 * metadata. Loop over the transaction's entire buffer list:
552 */
553 write_lock(&journal->j_state_lock);
554 commit_transaction->t_state = T_COMMIT;
555 write_unlock(&journal->j_state_lock);
556
557 trace_jbd2_commit_logging(journal, commit_transaction);
558 stats.run.rs_logging = jiffies;
559 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
560 stats.run.rs_logging);
561 stats.run.rs_blocks =
562 atomic_read(&commit_transaction->t_outstanding_credits);
563 stats.run.rs_blocks_logged = 0;
564
565 J_ASSERT(commit_transaction->t_nr_buffers <=
566 atomic_read(&commit_transaction->t_outstanding_credits));
567
568 err = 0;
569 descriptor = NULL;
570 bufs = 0;
571 blk_start_plug(&plug);
572 while (commit_transaction->t_buffers) {
573
574 /* Find the next buffer to be journaled... */
575
576 jh = commit_transaction->t_buffers;
577
578 /* If we're in abort mode, we just un-journal the buffer and
579 release it. */
580
581 if (is_journal_aborted(journal)) {
582 clear_buffer_jbddirty(jh2bh(jh));
583 JBUFFER_TRACE(jh, "journal is aborting: refile");
584 jbd2_buffer_abort_trigger(jh,
585 jh->b_frozen_data ?
586 jh->b_frozen_triggers :
587 jh->b_triggers);
588 jbd2_journal_refile_buffer(journal, jh);
589 /* If that was the last one, we need to clean up
590 * any descriptor buffers which may have been
591 * already allocated, even if we are now
592 * aborting. */
593 if (!commit_transaction->t_buffers)
594 goto start_journal_io;
595 continue;
596 }
597
598 /* Make sure we have a descriptor block in which to
599 record the metadata buffer. */
600
601 if (!descriptor) {
602 struct buffer_head *bh;
603
604 J_ASSERT (bufs == 0);
605
606 jbd_debug(4, "JBD2: get descriptor\n");
607
608 descriptor = jbd2_journal_get_descriptor_buffer(journal);
609 if (!descriptor) {
610 jbd2_journal_abort(journal, -EIO);
611 continue;
612 }
613
614 bh = jh2bh(descriptor);
615 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
616 (unsigned long long)bh->b_blocknr, bh->b_data);
617 header = (journal_header_t *)&bh->b_data[0];
618 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
619 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK);
620 header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
621
622 tagp = &bh->b_data[sizeof(journal_header_t)];
623 space_left = bh->b_size - sizeof(journal_header_t);
624 first_tag = 1;
625 set_buffer_jwrite(bh);
626 set_buffer_dirty(bh);
627 wbuf[bufs++] = bh;
628
629 /* Record it so that we can wait for IO
630 completion later */
631 BUFFER_TRACE(bh, "ph3: file as descriptor");
632 jbd2_journal_file_buffer(descriptor, commit_transaction,
633 BJ_LogCtl);
634 }
635
636 /* Where is the buffer to be written? */
637
638 err = jbd2_journal_next_log_block(journal, &blocknr);
639 /* If the block mapping failed, just abandon the buffer
640 and repeat this loop: we'll fall into the
641 refile-on-abort condition above. */
642 if (err) {
643 jbd2_journal_abort(journal, err);
644 continue;
645 }
646
647 /*
648 * start_this_handle() uses t_outstanding_credits to determine
649 * the free space in the log, but this counter is changed
650 * by jbd2_journal_next_log_block() also.
651 */
652 atomic_dec(&commit_transaction->t_outstanding_credits);
653
654 /* Bump b_count to prevent truncate from stumbling over
655 the shadowed buffer! @@@ This can go if we ever get
656 rid of the BJ_IO/BJ_Shadow pairing of buffers. */
657 atomic_inc(&jh2bh(jh)->b_count);
658
659 /* Make a temporary IO buffer with which to write it out
660 (this will requeue both the metadata buffer and the
661 temporary IO buffer). new_bh goes on BJ_IO*/
662
663 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
664 /*
665 * akpm: jbd2_journal_write_metadata_buffer() sets
666 * new_bh->b_transaction to commit_transaction.
667 * We need to clean this up before we release new_bh
668 * (which is of type BJ_IO)
669 */
670 JBUFFER_TRACE(jh, "ph3: write metadata");
671 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
672 jh, &new_jh, blocknr);
673 if (flags < 0) {
674 jbd2_journal_abort(journal, flags);
675 continue;
676 }
677 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state);
678 wbuf[bufs++] = jh2bh(new_jh);
679
680 /* Record the new block's tag in the current descriptor
681 buffer */
682
683 tag_flag = 0;
684 if (flags & 1)
685 tag_flag |= JBD2_FLAG_ESCAPE;
686 if (!first_tag)
687 tag_flag |= JBD2_FLAG_SAME_UUID;
688
689 tag = (journal_block_tag_t *) tagp;
690 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr);
691 tag->t_flags = cpu_to_be16(tag_flag);
692 jbd2_block_tag_csum_set(journal, tag, jh2bh(new_jh),
693 commit_transaction->t_tid);
694 tagp += tag_bytes;
695 space_left -= tag_bytes;
696
697 if (first_tag) {
698 memcpy (tagp, journal->j_uuid, 16);
699 tagp += 16;
700 space_left -= 16;
701 first_tag = 0;
702 }
703
704 /* If there's no more to do, or if the descriptor is full,
705 let the IO rip! */
706
707 if (bufs == journal->j_wbufsize ||
708 commit_transaction->t_buffers == NULL ||
709 space_left < tag_bytes + 16 + csum_size) {
710
711 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
712
713 /* Write an end-of-descriptor marker before
714 submitting the IOs. "tag" still points to
715 the last tag we set up. */
716
717 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
718
719 jbd2_descr_block_csum_set(journal, descriptor);
720start_journal_io:
721 for (i = 0; i < bufs; i++) {
722 struct buffer_head *bh = wbuf[i];
723 /*
724 * Compute checksum.
725 */
726 if (JBD2_HAS_COMPAT_FEATURE(journal,
727 JBD2_FEATURE_COMPAT_CHECKSUM)) {
728 crc32_sum =
729 jbd2_checksum_data(crc32_sum, bh);
730 }
731
732 lock_buffer(bh);
733 clear_buffer_dirty(bh);
734 set_buffer_uptodate(bh);
735 bh->b_end_io = journal_end_buffer_io_sync;
736 submit_bh(WRITE_SYNC, bh);
737 }
738 cond_resched();
739 stats.run.rs_blocks_logged += bufs;
740
741 /* Force a new descriptor to be generated next
742 time round the loop. */
743 descriptor = NULL;
744 bufs = 0;
745 }
746 }
747
748 err = journal_finish_inode_data_buffers(journal, commit_transaction);
749 if (err) {
750 printk(KERN_WARNING
751 "JBD2: Detected IO errors while flushing file data "
752 "on %s\n", journal->j_devname);
753 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
754 jbd2_journal_abort(journal, err);
755 err = 0;
756 }
757
758 /*
759 * Get current oldest transaction in the log before we issue flush
760 * to the filesystem device. After the flush we can be sure that
761 * blocks of all older transactions are checkpointed to persistent
762 * storage and we will be safe to update journal start in the
763 * superblock with the numbers we get here.
764 */
765 update_tail =
766 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
767
768 write_lock(&journal->j_state_lock);
769 if (update_tail) {
770 long freed = first_block - journal->j_tail;
771
772 if (first_block < journal->j_tail)
773 freed += journal->j_last - journal->j_first;
774 /* Update tail only if we free significant amount of space */
775 if (freed < journal->j_maxlen / 4)
776 update_tail = 0;
777 }
778 J_ASSERT(commit_transaction->t_state == T_COMMIT);
779 commit_transaction->t_state = T_COMMIT_DFLUSH;
780 write_unlock(&journal->j_state_lock);
781
782 /*
783 * If the journal is not located on the file system device,
784 * then we must flush the file system device before we issue
785 * the commit record
786 */
787 if (commit_transaction->t_need_data_flush &&
788 (journal->j_fs_dev != journal->j_dev) &&
789 (journal->j_flags & JBD2_BARRIER))
790 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
791
792 /* Done it all: now write the commit record asynchronously. */
793 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
794 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
795 err = journal_submit_commit_record(journal, commit_transaction,
796 &cbh, crc32_sum);
797 if (err)
798 __jbd2_journal_abort_hard(journal);
799 }
800
801 blk_finish_plug(&plug);
802
803 /* Lo and behold: we have just managed to send a transaction to
804 the log. Before we can commit it, wait for the IO so far to
805 complete. Control buffers being written are on the
806 transaction's t_log_list queue, and metadata buffers are on
807 the t_iobuf_list queue.
808
809 Wait for the buffers in reverse order. That way we are
810 less likely to be woken up until all IOs have completed, and
811 so we incur less scheduling load.
812 */
813
814 jbd_debug(3, "JBD2: commit phase 3\n");
815
816 /*
817 * akpm: these are BJ_IO, and j_list_lock is not needed.
818 * See __journal_try_to_free_buffer.
819 */
820wait_for_iobuf:
821 while (commit_transaction->t_iobuf_list != NULL) {
822 struct buffer_head *bh;
823
824 jh = commit_transaction->t_iobuf_list->b_tprev;
825 bh = jh2bh(jh);
826 if (buffer_locked(bh)) {
827 wait_on_buffer(bh);
828 goto wait_for_iobuf;
829 }
830 if (cond_resched())
831 goto wait_for_iobuf;
832
833 if (unlikely(!buffer_uptodate(bh)))
834 err = -EIO;
835
836 clear_buffer_jwrite(bh);
837
838 JBUFFER_TRACE(jh, "ph4: unfile after journal write");
839 jbd2_journal_unfile_buffer(journal, jh);
840
841 /*
842 * ->t_iobuf_list should contain only dummy buffer_heads
843 * which were created by jbd2_journal_write_metadata_buffer().
844 */
845 BUFFER_TRACE(bh, "dumping temporary bh");
846 jbd2_journal_put_journal_head(jh);
847 __brelse(bh);
848 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
849 free_buffer_head(bh);
850
851 /* We also have to unlock and free the corresponding
852 shadowed buffer */
853 jh = commit_transaction->t_shadow_list->b_tprev;
854 bh = jh2bh(jh);
855 clear_bit(BH_JWrite, &bh->b_state);
856 J_ASSERT_BH(bh, buffer_jbddirty(bh));
857
858 /* The metadata is now released for reuse, but we need
859 to remember it against this transaction so that when
860 we finally commit, we can do any checkpointing
861 required. */
862 JBUFFER_TRACE(jh, "file as BJ_Forget");
863 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
864 /*
865 * Wake up any transactions which were waiting for this IO to
866 * complete. The barrier must be here so that changes by
867 * jbd2_journal_file_buffer() take effect before wake_up_bit()
868 * does the waitqueue check.
869 */
870 smp_mb();
871 wake_up_bit(&bh->b_state, BH_Unshadow);
872 JBUFFER_TRACE(jh, "brelse shadowed buffer");
873 __brelse(bh);
874 }
875
876 J_ASSERT (commit_transaction->t_shadow_list == NULL);
877
878 jbd_debug(3, "JBD2: commit phase 4\n");
879
880 /* Here we wait for the revoke record and descriptor record buffers */
881 wait_for_ctlbuf:
882 while (commit_transaction->t_log_list != NULL) {
883 struct buffer_head *bh;
884
885 jh = commit_transaction->t_log_list->b_tprev;
886 bh = jh2bh(jh);
887 if (buffer_locked(bh)) {
888 wait_on_buffer(bh);
889 goto wait_for_ctlbuf;
890 }
891 if (cond_resched())
892 goto wait_for_ctlbuf;
893
894 if (unlikely(!buffer_uptodate(bh)))
895 err = -EIO;
896
897 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
898 clear_buffer_jwrite(bh);
899 jbd2_journal_unfile_buffer(journal, jh);
900 jbd2_journal_put_journal_head(jh);
901 __brelse(bh); /* One for getblk */
902 /* AKPM: bforget here */
903 }
904
905 if (err)
906 jbd2_journal_abort(journal, err);
907
908 jbd_debug(3, "JBD2: commit phase 5\n");
909 write_lock(&journal->j_state_lock);
910 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
911 commit_transaction->t_state = T_COMMIT_JFLUSH;
912 write_unlock(&journal->j_state_lock);
913
914 if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
915 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
916 err = journal_submit_commit_record(journal, commit_transaction,
917 &cbh, crc32_sum);
918 if (err)
919 __jbd2_journal_abort_hard(journal);
920 }
921 if (cbh)
922 err = journal_wait_on_commit_record(journal, cbh);
923 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
924 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) &&
925 journal->j_flags & JBD2_BARRIER) {
926 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
927 }
928
929 if (err)
930 jbd2_journal_abort(journal, err);
931
932 /*
933 * Now disk caches for filesystem device are flushed so we are safe to
934 * erase checkpointed transactions from the log by updating journal
935 * superblock.
936 */
937 if (update_tail)
938 jbd2_update_log_tail(journal, first_tid, first_block);
939
940 /* End of a transaction! Finally, we can do checkpoint
941 processing: any buffers committed as a result of this
942 transaction can be removed from any checkpoint list it was on
943 before. */
944
945 jbd_debug(3, "JBD2: commit phase 6\n");
946
947 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
948 J_ASSERT(commit_transaction->t_buffers == NULL);
949 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
950 J_ASSERT(commit_transaction->t_iobuf_list == NULL);
951 J_ASSERT(commit_transaction->t_shadow_list == NULL);
952 J_ASSERT(commit_transaction->t_log_list == NULL);
953
954restart_loop:
955 /*
956 * As there are other places (journal_unmap_buffer()) adding buffers
957 * to this list we have to be careful and hold the j_list_lock.
958 */
959 spin_lock(&journal->j_list_lock);
960 while (commit_transaction->t_forget) {
961 transaction_t *cp_transaction;
962 struct buffer_head *bh;
963 int try_to_free = 0;
964
965 jh = commit_transaction->t_forget;
966 spin_unlock(&journal->j_list_lock);
967 bh = jh2bh(jh);
968 /*
969 * Get a reference so that bh cannot be freed before we are
970 * done with it.
971 */
972 get_bh(bh);
973 jbd_lock_bh_state(bh);
974 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
975
976 /*
977 * If there is undo-protected committed data against
978 * this buffer, then we can remove it now. If it is a
979 * buffer needing such protection, the old frozen_data
980 * field now points to a committed version of the
981 * buffer, so rotate that field to the new committed
982 * data.
983 *
984 * Otherwise, we can just throw away the frozen data now.
985 *
986 * We also know that the frozen data has already fired
987 * its triggers if they exist, so we can clear that too.
988 */
989 if (jh->b_committed_data) {
990 jbd2_free(jh->b_committed_data, bh->b_size);
991 jh->b_committed_data = NULL;
992 if (jh->b_frozen_data) {
993 jh->b_committed_data = jh->b_frozen_data;
994 jh->b_frozen_data = NULL;
995 jh->b_frozen_triggers = NULL;
996 }
997 } else if (jh->b_frozen_data) {
998 jbd2_free(jh->b_frozen_data, bh->b_size);
999 jh->b_frozen_data = NULL;
1000 jh->b_frozen_triggers = NULL;
1001 }
1002
1003 spin_lock(&journal->j_list_lock);
1004 cp_transaction = jh->b_cp_transaction;
1005 if (cp_transaction) {
1006 JBUFFER_TRACE(jh, "remove from old cp transaction");
1007 cp_transaction->t_chp_stats.cs_dropped++;
1008 __jbd2_journal_remove_checkpoint(jh);
1009 }
1010
1011 /* Only re-checkpoint the buffer_head if it is marked
1012 * dirty. If the buffer was added to the BJ_Forget list
1013 * by jbd2_journal_forget, it may no longer be dirty and
1014 * there's no point in keeping a checkpoint record for
1015 * it. */
1016
1017 /* A buffer which has been freed while still being
1018 * journaled by a previous transaction may end up still
1019 * being dirty here, but we want to avoid writing back
1020 * that buffer in the future after the "add to orphan"
1021 * operation been committed, That's not only a performance
1022 * gain, it also stops aliasing problems if the buffer is
1023 * left behind for writeback and gets reallocated for another
1024 * use in a different page. */
1025 if (buffer_freed(bh) && !jh->b_next_transaction) {
1026 clear_buffer_freed(bh);
1027 clear_buffer_jbddirty(bh);
1028 }
1029
1030 if (buffer_jbddirty(bh)) {
1031 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1032 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1033 if (is_journal_aborted(journal))
1034 clear_buffer_jbddirty(bh);
1035 } else {
1036 J_ASSERT_BH(bh, !buffer_dirty(bh));
1037 /*
1038 * The buffer on BJ_Forget list and not jbddirty means
1039 * it has been freed by this transaction and hence it
1040 * could not have been reallocated until this
1041 * transaction has committed. *BUT* it could be
1042 * reallocated once we have written all the data to
1043 * disk and before we process the buffer on BJ_Forget
1044 * list.
1045 */
1046 if (!jh->b_next_transaction)
1047 try_to_free = 1;
1048 }
1049 JBUFFER_TRACE(jh, "refile or unfile buffer");
1050 __jbd2_journal_refile_buffer(jh);
1051 jbd_unlock_bh_state(bh);
1052 if (try_to_free)
1053 release_buffer_page(bh); /* Drops bh reference */
1054 else
1055 __brelse(bh);
1056 cond_resched_lock(&journal->j_list_lock);
1057 }
1058 spin_unlock(&journal->j_list_lock);
1059 /*
1060 * This is a bit sleazy. We use j_list_lock to protect transition
1061 * of a transaction into T_FINISHED state and calling
1062 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1063 * other checkpointing code processing the transaction...
1064 */
1065 write_lock(&journal->j_state_lock);
1066 spin_lock(&journal->j_list_lock);
1067 /*
1068 * Now recheck if some buffers did not get attached to the transaction
1069 * while the lock was dropped...
1070 */
1071 if (commit_transaction->t_forget) {
1072 spin_unlock(&journal->j_list_lock);
1073 write_unlock(&journal->j_state_lock);
1074 goto restart_loop;
1075 }
1076
1077 /* Done with this transaction! */
1078
1079 jbd_debug(3, "JBD2: commit phase 7\n");
1080
1081 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1082
1083 commit_transaction->t_start = jiffies;
1084 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1085 commit_transaction->t_start);
1086
1087 /*
1088 * File the transaction statistics
1089 */
1090 stats.ts_tid = commit_transaction->t_tid;
1091 stats.run.rs_handle_count =
1092 atomic_read(&commit_transaction->t_handle_count);
1093 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1094 commit_transaction->t_tid, &stats.run);
1095
1096 /*
1097 * Calculate overall stats
1098 */
1099 spin_lock(&journal->j_history_lock);
1100 journal->j_stats.ts_tid++;
1101 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1102 journal->j_stats.run.rs_running += stats.run.rs_running;
1103 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1104 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1105 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1106 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1107 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1108 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1109 spin_unlock(&journal->j_history_lock);
1110
1111 commit_transaction->t_state = T_FINISHED;
1112 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1113 journal->j_commit_sequence = commit_transaction->t_tid;
1114 journal->j_committing_transaction = NULL;
1115 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1116
1117 /*
1118 * weight the commit time higher than the average time so we don't
1119 * react too strongly to vast changes in the commit time
1120 */
1121 if (likely(journal->j_average_commit_time))
1122 journal->j_average_commit_time = (commit_time +
1123 journal->j_average_commit_time*3) / 4;
1124 else
1125 journal->j_average_commit_time = commit_time;
1126 write_unlock(&journal->j_state_lock);
1127
1128 if (commit_transaction->t_checkpoint_list == NULL &&
1129 commit_transaction->t_checkpoint_io_list == NULL) {
1130 __jbd2_journal_drop_transaction(journal, commit_transaction);
1131 to_free = 1;
1132 } else {
1133 if (journal->j_checkpoint_transactions == NULL) {
1134 journal->j_checkpoint_transactions = commit_transaction;
1135 commit_transaction->t_cpnext = commit_transaction;
1136 commit_transaction->t_cpprev = commit_transaction;
1137 } else {
1138 commit_transaction->t_cpnext =
1139 journal->j_checkpoint_transactions;
1140 commit_transaction->t_cpprev =
1141 commit_transaction->t_cpnext->t_cpprev;
1142 commit_transaction->t_cpnext->t_cpprev =
1143 commit_transaction;
1144 commit_transaction->t_cpprev->t_cpnext =
1145 commit_transaction;
1146 }
1147 }
1148 spin_unlock(&journal->j_list_lock);
1149
1150 if (journal->j_commit_callback)
1151 journal->j_commit_callback(journal, commit_transaction);
1152
1153 trace_jbd2_end_commit(journal, commit_transaction);
1154 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1155 journal->j_commit_sequence, journal->j_tail_sequence);
1156 if (to_free)
1157 jbd2_journal_free_transaction(commit_transaction);
1158
1159 wake_up(&journal->j_wait_done_commit);
1160}