Loading...
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;
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 ktime_get_coarse_real_ts64(&now);
138 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
139 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
140
141 if (jbd2_has_feature_checksum(journal)) {
142 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
143 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
144 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
145 }
146 jbd2_commit_block_csum_set(journal, bh);
147
148 BUFFER_TRACE(bh, "submit commit block");
149 lock_buffer(bh);
150 clear_buffer_dirty(bh);
151 set_buffer_uptodate(bh);
152 bh->b_end_io = journal_end_buffer_io_sync;
153
154 if (journal->j_flags & JBD2_BARRIER &&
155 !jbd2_has_feature_async_commit(journal))
156 ret = submit_bh(REQ_OP_WRITE,
157 REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh);
158 else
159 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
160
161 *cbh = bh;
162 return ret;
163}
164
165/*
166 * This function along with journal_submit_commit_record
167 * allows to write the commit record asynchronously.
168 */
169static int journal_wait_on_commit_record(journal_t *journal,
170 struct buffer_head *bh)
171{
172 int ret = 0;
173
174 clear_buffer_dirty(bh);
175 wait_on_buffer(bh);
176
177 if (unlikely(!buffer_uptodate(bh)))
178 ret = -EIO;
179 put_bh(bh); /* One for getblk() */
180
181 return ret;
182}
183
184/*
185 * write the filemap data using writepage() address_space_operations.
186 * We don't do block allocation here even for delalloc. We don't
187 * use writepages() because with delayed allocation we may be doing
188 * block allocation in writepages().
189 */
190static int journal_submit_inode_data_buffers(struct address_space *mapping,
191 loff_t dirty_start, loff_t dirty_end)
192{
193 int ret;
194 struct writeback_control wbc = {
195 .sync_mode = WB_SYNC_ALL,
196 .nr_to_write = mapping->nrpages * 2,
197 .range_start = dirty_start,
198 .range_end = dirty_end,
199 };
200
201 ret = generic_writepages(mapping, &wbc);
202 return ret;
203}
204
205/*
206 * Submit all the data buffers of inode associated with the transaction to
207 * disk.
208 *
209 * We are in a committing transaction. Therefore no new inode can be added to
210 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
211 * operate on from being released while we write out pages.
212 */
213static int journal_submit_data_buffers(journal_t *journal,
214 transaction_t *commit_transaction)
215{
216 struct jbd2_inode *jinode;
217 int err, ret = 0;
218 struct address_space *mapping;
219
220 spin_lock(&journal->j_list_lock);
221 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
222 loff_t dirty_start = jinode->i_dirty_start;
223 loff_t dirty_end = jinode->i_dirty_end;
224
225 if (!(jinode->i_flags & JI_WRITE_DATA))
226 continue;
227 mapping = jinode->i_vfs_inode->i_mapping;
228 jinode->i_flags |= JI_COMMIT_RUNNING;
229 spin_unlock(&journal->j_list_lock);
230 /*
231 * submit the inode data buffers. We use writepage
232 * instead of writepages. Because writepages can do
233 * block allocation with delalloc. We need to write
234 * only allocated blocks here.
235 */
236 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
237 err = journal_submit_inode_data_buffers(mapping, dirty_start,
238 dirty_end);
239 if (!ret)
240 ret = err;
241 spin_lock(&journal->j_list_lock);
242 J_ASSERT(jinode->i_transaction == commit_transaction);
243 jinode->i_flags &= ~JI_COMMIT_RUNNING;
244 smp_mb();
245 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
246 }
247 spin_unlock(&journal->j_list_lock);
248 return ret;
249}
250
251/*
252 * Wait for data submitted for writeout, refile inodes to proper
253 * transaction if needed.
254 *
255 */
256static int journal_finish_inode_data_buffers(journal_t *journal,
257 transaction_t *commit_transaction)
258{
259 struct jbd2_inode *jinode, *next_i;
260 int err, ret = 0;
261
262 /* For locking, see the comment in journal_submit_data_buffers() */
263 spin_lock(&journal->j_list_lock);
264 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
265 loff_t dirty_start = jinode->i_dirty_start;
266 loff_t dirty_end = jinode->i_dirty_end;
267
268 if (!(jinode->i_flags & JI_WAIT_DATA))
269 continue;
270 jinode->i_flags |= JI_COMMIT_RUNNING;
271 spin_unlock(&journal->j_list_lock);
272 err = filemap_fdatawait_range_keep_errors(
273 jinode->i_vfs_inode->i_mapping, dirty_start,
274 dirty_end);
275 if (!ret)
276 ret = err;
277 spin_lock(&journal->j_list_lock);
278 jinode->i_flags &= ~JI_COMMIT_RUNNING;
279 smp_mb();
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 jinode->i_dirty_start = 0;
295 jinode->i_dirty_end = 0;
296 }
297 }
298 spin_unlock(&journal->j_list_lock);
299
300 return ret;
301}
302
303static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
304{
305 struct page *page = bh->b_page;
306 char *addr;
307 __u32 checksum;
308
309 addr = kmap_atomic(page);
310 checksum = crc32_be(crc32_sum,
311 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
312 kunmap_atomic(addr);
313
314 return checksum;
315}
316
317static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
318 unsigned long long block)
319{
320 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
321 if (jbd2_has_feature_64bit(j))
322 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
323}
324
325static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
326 struct buffer_head *bh, __u32 sequence)
327{
328 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
329 struct page *page = bh->b_page;
330 __u8 *addr;
331 __u32 csum32;
332 __be32 seq;
333
334 if (!jbd2_journal_has_csum_v2or3(j))
335 return;
336
337 seq = cpu_to_be32(sequence);
338 addr = kmap_atomic(page);
339 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
340 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
341 bh->b_size);
342 kunmap_atomic(addr);
343
344 if (jbd2_has_feature_csum3(j))
345 tag3->t_checksum = cpu_to_be32(csum32);
346 else
347 tag->t_checksum = cpu_to_be16(csum32);
348}
349/*
350 * jbd2_journal_commit_transaction
351 *
352 * The primary function for committing a transaction to the log. This
353 * function is called by the journal thread to begin a complete commit.
354 */
355void jbd2_journal_commit_transaction(journal_t *journal)
356{
357 struct transaction_stats_s stats;
358 transaction_t *commit_transaction;
359 struct journal_head *jh;
360 struct buffer_head *descriptor;
361 struct buffer_head **wbuf = journal->j_wbuf;
362 int bufs;
363 int flags;
364 int err;
365 unsigned long long blocknr;
366 ktime_t start_time;
367 u64 commit_time;
368 char *tagp = NULL;
369 journal_block_tag_t *tag = NULL;
370 int space_left = 0;
371 int first_tag = 0;
372 int tag_flag;
373 int i;
374 int tag_bytes = journal_tag_bytes(journal);
375 struct buffer_head *cbh = NULL; /* For transactional checksums */
376 __u32 crc32_sum = ~0;
377 struct blk_plug plug;
378 /* Tail of the journal */
379 unsigned long first_block;
380 tid_t first_tid;
381 int update_tail;
382 int csum_size = 0;
383 LIST_HEAD(io_bufs);
384 LIST_HEAD(log_bufs);
385
386 if (jbd2_journal_has_csum_v2or3(journal))
387 csum_size = sizeof(struct jbd2_journal_block_tail);
388
389 /*
390 * First job: lock down the current transaction and wait for
391 * all outstanding updates to complete.
392 */
393
394 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
395 if (journal->j_flags & JBD2_FLUSHED) {
396 jbd_debug(3, "super block updated\n");
397 mutex_lock_io(&journal->j_checkpoint_mutex);
398 /*
399 * We hold j_checkpoint_mutex so tail cannot change under us.
400 * We don't need any special data guarantees for writing sb
401 * since journal is empty and it is ok for write to be
402 * flushed only with transaction commit.
403 */
404 jbd2_journal_update_sb_log_tail(journal,
405 journal->j_tail_sequence,
406 journal->j_tail,
407 REQ_SYNC);
408 mutex_unlock(&journal->j_checkpoint_mutex);
409 } else {
410 jbd_debug(3, "superblock not updated\n");
411 }
412
413 J_ASSERT(journal->j_running_transaction != NULL);
414 J_ASSERT(journal->j_committing_transaction == NULL);
415
416 commit_transaction = journal->j_running_transaction;
417
418 trace_jbd2_start_commit(journal, commit_transaction);
419 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
420 commit_transaction->t_tid);
421
422 write_lock(&journal->j_state_lock);
423 J_ASSERT(commit_transaction->t_state == T_RUNNING);
424 commit_transaction->t_state = T_LOCKED;
425
426 trace_jbd2_commit_locking(journal, commit_transaction);
427 stats.run.rs_wait = commit_transaction->t_max_wait;
428 stats.run.rs_request_delay = 0;
429 stats.run.rs_locked = jiffies;
430 if (commit_transaction->t_requested)
431 stats.run.rs_request_delay =
432 jbd2_time_diff(commit_transaction->t_requested,
433 stats.run.rs_locked);
434 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
435 stats.run.rs_locked);
436
437 spin_lock(&commit_transaction->t_handle_lock);
438 while (atomic_read(&commit_transaction->t_updates)) {
439 DEFINE_WAIT(wait);
440
441 prepare_to_wait(&journal->j_wait_updates, &wait,
442 TASK_UNINTERRUPTIBLE);
443 if (atomic_read(&commit_transaction->t_updates)) {
444 spin_unlock(&commit_transaction->t_handle_lock);
445 write_unlock(&journal->j_state_lock);
446 schedule();
447 write_lock(&journal->j_state_lock);
448 spin_lock(&commit_transaction->t_handle_lock);
449 }
450 finish_wait(&journal->j_wait_updates, &wait);
451 }
452 spin_unlock(&commit_transaction->t_handle_lock);
453 commit_transaction->t_state = T_SWITCH;
454 write_unlock(&journal->j_state_lock);
455
456 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
457 journal->j_max_transaction_buffers);
458
459 /*
460 * First thing we are allowed to do is to discard any remaining
461 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
462 * that there are no such buffers: if a large filesystem
463 * operation like a truncate needs to split itself over multiple
464 * transactions, then it may try to do a jbd2_journal_restart() while
465 * there are still BJ_Reserved buffers outstanding. These must
466 * be released cleanly from the current transaction.
467 *
468 * In this case, the filesystem must still reserve write access
469 * again before modifying the buffer in the new transaction, but
470 * we do not require it to remember exactly which old buffers it
471 * has reserved. This is consistent with the existing behaviour
472 * that multiple jbd2_journal_get_write_access() calls to the same
473 * buffer are perfectly permissible.
474 */
475 while (commit_transaction->t_reserved_list) {
476 jh = commit_transaction->t_reserved_list;
477 JBUFFER_TRACE(jh, "reserved, unused: refile");
478 /*
479 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
480 * leave undo-committed data.
481 */
482 if (jh->b_committed_data) {
483 struct buffer_head *bh = jh2bh(jh);
484
485 spin_lock(&jh->b_state_lock);
486 jbd2_free(jh->b_committed_data, bh->b_size);
487 jh->b_committed_data = NULL;
488 spin_unlock(&jh->b_state_lock);
489 }
490 jbd2_journal_refile_buffer(journal, jh);
491 }
492
493 /*
494 * Now try to drop any written-back buffers from the journal's
495 * checkpoint lists. We do this *before* commit because it potentially
496 * frees some memory
497 */
498 spin_lock(&journal->j_list_lock);
499 __jbd2_journal_clean_checkpoint_list(journal, false);
500 spin_unlock(&journal->j_list_lock);
501
502 jbd_debug(3, "JBD2: commit phase 1\n");
503
504 /*
505 * Clear revoked flag to reflect there is no revoked buffers
506 * in the next transaction which is going to be started.
507 */
508 jbd2_clear_buffer_revoked_flags(journal);
509
510 /*
511 * Switch to a new revoke table.
512 */
513 jbd2_journal_switch_revoke_table(journal);
514
515 /*
516 * Reserved credits cannot be claimed anymore, free them
517 */
518 atomic_sub(atomic_read(&journal->j_reserved_credits),
519 &commit_transaction->t_outstanding_credits);
520
521 write_lock(&journal->j_state_lock);
522 trace_jbd2_commit_flushing(journal, commit_transaction);
523 stats.run.rs_flushing = jiffies;
524 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
525 stats.run.rs_flushing);
526
527 commit_transaction->t_state = T_FLUSH;
528 journal->j_committing_transaction = commit_transaction;
529 journal->j_running_transaction = NULL;
530 start_time = ktime_get();
531 commit_transaction->t_log_start = journal->j_head;
532 wake_up(&journal->j_wait_transaction_locked);
533 write_unlock(&journal->j_state_lock);
534
535 jbd_debug(3, "JBD2: commit phase 2a\n");
536
537 /*
538 * Now start flushing things to disk, in the order they appear
539 * on the transaction lists. Data blocks go first.
540 */
541 err = journal_submit_data_buffers(journal, commit_transaction);
542 if (err)
543 jbd2_journal_abort(journal, err);
544
545 blk_start_plug(&plug);
546 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
547
548 jbd_debug(3, "JBD2: commit phase 2b\n");
549
550 /*
551 * Way to go: we have now written out all of the data for a
552 * transaction! Now comes the tricky part: we need to write out
553 * metadata. Loop over the transaction's entire buffer list:
554 */
555 write_lock(&journal->j_state_lock);
556 commit_transaction->t_state = T_COMMIT;
557 write_unlock(&journal->j_state_lock);
558
559 trace_jbd2_commit_logging(journal, commit_transaction);
560 stats.run.rs_logging = jiffies;
561 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
562 stats.run.rs_logging);
563 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
564 stats.run.rs_blocks_logged = 0;
565
566 J_ASSERT(commit_transaction->t_nr_buffers <=
567 atomic_read(&commit_transaction->t_outstanding_credits));
568
569 err = 0;
570 bufs = 0;
571 descriptor = NULL;
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 J_ASSERT (bufs == 0);
603
604 jbd_debug(4, "JBD2: get descriptor\n");
605
606 descriptor = jbd2_journal_get_descriptor_buffer(
607 commit_transaction,
608 JBD2_DESCRIPTOR_BLOCK);
609 if (!descriptor) {
610 jbd2_journal_abort(journal, -EIO);
611 continue;
612 }
613
614 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
615 (unsigned long long)descriptor->b_blocknr,
616 descriptor->b_data);
617 tagp = &descriptor->b_data[sizeof(journal_header_t)];
618 space_left = descriptor->b_size -
619 sizeof(journal_header_t);
620 first_tag = 1;
621 set_buffer_jwrite(descriptor);
622 set_buffer_dirty(descriptor);
623 wbuf[bufs++] = descriptor;
624
625 /* Record it so that we can wait for IO
626 completion later */
627 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
628 jbd2_file_log_bh(&log_bufs, descriptor);
629 }
630
631 /* Where is the buffer to be written? */
632
633 err = jbd2_journal_next_log_block(journal, &blocknr);
634 /* If the block mapping failed, just abandon the buffer
635 and repeat this loop: we'll fall into the
636 refile-on-abort condition above. */
637 if (err) {
638 jbd2_journal_abort(journal, err);
639 continue;
640 }
641
642 /*
643 * start_this_handle() uses t_outstanding_credits to determine
644 * the free space in the log.
645 */
646 atomic_dec(&commit_transaction->t_outstanding_credits);
647
648 /* Bump b_count to prevent truncate from stumbling over
649 the shadowed buffer! @@@ This can go if we ever get
650 rid of the shadow pairing of buffers. */
651 atomic_inc(&jh2bh(jh)->b_count);
652
653 /*
654 * Make a temporary IO buffer with which to write it out
655 * (this will requeue the metadata buffer to BJ_Shadow).
656 */
657 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
658 JBUFFER_TRACE(jh, "ph3: write metadata");
659 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
660 jh, &wbuf[bufs], blocknr);
661 if (flags < 0) {
662 jbd2_journal_abort(journal, flags);
663 continue;
664 }
665 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
666
667 /* Record the new block's tag in the current descriptor
668 buffer */
669
670 tag_flag = 0;
671 if (flags & 1)
672 tag_flag |= JBD2_FLAG_ESCAPE;
673 if (!first_tag)
674 tag_flag |= JBD2_FLAG_SAME_UUID;
675
676 tag = (journal_block_tag_t *) tagp;
677 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
678 tag->t_flags = cpu_to_be16(tag_flag);
679 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
680 commit_transaction->t_tid);
681 tagp += tag_bytes;
682 space_left -= tag_bytes;
683 bufs++;
684
685 if (first_tag) {
686 memcpy (tagp, journal->j_uuid, 16);
687 tagp += 16;
688 space_left -= 16;
689 first_tag = 0;
690 }
691
692 /* If there's no more to do, or if the descriptor is full,
693 let the IO rip! */
694
695 if (bufs == journal->j_wbufsize ||
696 commit_transaction->t_buffers == NULL ||
697 space_left < tag_bytes + 16 + csum_size) {
698
699 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
700
701 /* Write an end-of-descriptor marker before
702 submitting the IOs. "tag" still points to
703 the last tag we set up. */
704
705 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
706start_journal_io:
707 if (descriptor)
708 jbd2_descriptor_block_csum_set(journal,
709 descriptor);
710
711 for (i = 0; i < bufs; i++) {
712 struct buffer_head *bh = wbuf[i];
713 /*
714 * Compute checksum.
715 */
716 if (jbd2_has_feature_checksum(journal)) {
717 crc32_sum =
718 jbd2_checksum_data(crc32_sum, bh);
719 }
720
721 lock_buffer(bh);
722 clear_buffer_dirty(bh);
723 set_buffer_uptodate(bh);
724 bh->b_end_io = journal_end_buffer_io_sync;
725 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
726 }
727 cond_resched();
728
729 /* Force a new descriptor to be generated next
730 time round the loop. */
731 descriptor = NULL;
732 bufs = 0;
733 }
734 }
735
736 err = journal_finish_inode_data_buffers(journal, commit_transaction);
737 if (err) {
738 printk(KERN_WARNING
739 "JBD2: Detected IO errors while flushing file data "
740 "on %s\n", journal->j_devname);
741 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
742 jbd2_journal_abort(journal, err);
743 err = 0;
744 }
745
746 /*
747 * Get current oldest transaction in the log before we issue flush
748 * to the filesystem device. After the flush we can be sure that
749 * blocks of all older transactions are checkpointed to persistent
750 * storage and we will be safe to update journal start in the
751 * superblock with the numbers we get here.
752 */
753 update_tail =
754 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
755
756 write_lock(&journal->j_state_lock);
757 if (update_tail) {
758 long freed = first_block - journal->j_tail;
759
760 if (first_block < journal->j_tail)
761 freed += journal->j_last - journal->j_first;
762 /* Update tail only if we free significant amount of space */
763 if (freed < journal->j_maxlen / 4)
764 update_tail = 0;
765 }
766 J_ASSERT(commit_transaction->t_state == T_COMMIT);
767 commit_transaction->t_state = T_COMMIT_DFLUSH;
768 write_unlock(&journal->j_state_lock);
769
770 /*
771 * If the journal is not located on the file system device,
772 * then we must flush the file system device before we issue
773 * the commit record
774 */
775 if (commit_transaction->t_need_data_flush &&
776 (journal->j_fs_dev != journal->j_dev) &&
777 (journal->j_flags & JBD2_BARRIER))
778 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS);
779
780 /* Done it all: now write the commit record asynchronously. */
781 if (jbd2_has_feature_async_commit(journal)) {
782 err = journal_submit_commit_record(journal, commit_transaction,
783 &cbh, crc32_sum);
784 if (err)
785 jbd2_journal_abort(journal, err);
786 }
787
788 blk_finish_plug(&plug);
789
790 /* Lo and behold: we have just managed to send a transaction to
791 the log. Before we can commit it, wait for the IO so far to
792 complete. Control buffers being written are on the
793 transaction's t_log_list queue, and metadata buffers are on
794 the io_bufs list.
795
796 Wait for the buffers in reverse order. That way we are
797 less likely to be woken up until all IOs have completed, and
798 so we incur less scheduling load.
799 */
800
801 jbd_debug(3, "JBD2: commit phase 3\n");
802
803 while (!list_empty(&io_bufs)) {
804 struct buffer_head *bh = list_entry(io_bufs.prev,
805 struct buffer_head,
806 b_assoc_buffers);
807
808 wait_on_buffer(bh);
809 cond_resched();
810
811 if (unlikely(!buffer_uptodate(bh)))
812 err = -EIO;
813 jbd2_unfile_log_bh(bh);
814 stats.run.rs_blocks_logged++;
815
816 /*
817 * The list contains temporary buffer heads created by
818 * jbd2_journal_write_metadata_buffer().
819 */
820 BUFFER_TRACE(bh, "dumping temporary bh");
821 __brelse(bh);
822 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
823 free_buffer_head(bh);
824
825 /* We also have to refile the corresponding shadowed buffer */
826 jh = commit_transaction->t_shadow_list->b_tprev;
827 bh = jh2bh(jh);
828 clear_buffer_jwrite(bh);
829 J_ASSERT_BH(bh, buffer_jbddirty(bh));
830 J_ASSERT_BH(bh, !buffer_shadow(bh));
831
832 /* The metadata is now released for reuse, but we need
833 to remember it against this transaction so that when
834 we finally commit, we can do any checkpointing
835 required. */
836 JBUFFER_TRACE(jh, "file as BJ_Forget");
837 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
838 JBUFFER_TRACE(jh, "brelse shadowed buffer");
839 __brelse(bh);
840 }
841
842 J_ASSERT (commit_transaction->t_shadow_list == NULL);
843
844 jbd_debug(3, "JBD2: commit phase 4\n");
845
846 /* Here we wait for the revoke record and descriptor record buffers */
847 while (!list_empty(&log_bufs)) {
848 struct buffer_head *bh;
849
850 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
851 wait_on_buffer(bh);
852 cond_resched();
853
854 if (unlikely(!buffer_uptodate(bh)))
855 err = -EIO;
856
857 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
858 clear_buffer_jwrite(bh);
859 jbd2_unfile_log_bh(bh);
860 stats.run.rs_blocks_logged++;
861 __brelse(bh); /* One for getblk */
862 /* AKPM: bforget here */
863 }
864
865 if (err)
866 jbd2_journal_abort(journal, err);
867
868 jbd_debug(3, "JBD2: commit phase 5\n");
869 write_lock(&journal->j_state_lock);
870 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
871 commit_transaction->t_state = T_COMMIT_JFLUSH;
872 write_unlock(&journal->j_state_lock);
873
874 if (!jbd2_has_feature_async_commit(journal)) {
875 err = journal_submit_commit_record(journal, commit_transaction,
876 &cbh, crc32_sum);
877 if (err)
878 jbd2_journal_abort(journal, err);
879 }
880 if (cbh)
881 err = journal_wait_on_commit_record(journal, cbh);
882 stats.run.rs_blocks_logged++;
883 if (jbd2_has_feature_async_commit(journal) &&
884 journal->j_flags & JBD2_BARRIER) {
885 blkdev_issue_flush(journal->j_dev, GFP_NOFS);
886 }
887
888 if (err)
889 jbd2_journal_abort(journal, err);
890
891 WARN_ON_ONCE(
892 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
893
894 /*
895 * Now disk caches for filesystem device are flushed so we are safe to
896 * erase checkpointed transactions from the log by updating journal
897 * superblock.
898 */
899 if (update_tail)
900 jbd2_update_log_tail(journal, first_tid, first_block);
901
902 /* End of a transaction! Finally, we can do checkpoint
903 processing: any buffers committed as a result of this
904 transaction can be removed from any checkpoint list it was on
905 before. */
906
907 jbd_debug(3, "JBD2: commit phase 6\n");
908
909 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
910 J_ASSERT(commit_transaction->t_buffers == NULL);
911 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
912 J_ASSERT(commit_transaction->t_shadow_list == NULL);
913
914restart_loop:
915 /*
916 * As there are other places (journal_unmap_buffer()) adding buffers
917 * to this list we have to be careful and hold the j_list_lock.
918 */
919 spin_lock(&journal->j_list_lock);
920 while (commit_transaction->t_forget) {
921 transaction_t *cp_transaction;
922 struct buffer_head *bh;
923 int try_to_free = 0;
924 bool drop_ref;
925
926 jh = commit_transaction->t_forget;
927 spin_unlock(&journal->j_list_lock);
928 bh = jh2bh(jh);
929 /*
930 * Get a reference so that bh cannot be freed before we are
931 * done with it.
932 */
933 get_bh(bh);
934 spin_lock(&jh->b_state_lock);
935 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
936
937 /*
938 * If there is undo-protected committed data against
939 * this buffer, then we can remove it now. If it is a
940 * buffer needing such protection, the old frozen_data
941 * field now points to a committed version of the
942 * buffer, so rotate that field to the new committed
943 * data.
944 *
945 * Otherwise, we can just throw away the frozen data now.
946 *
947 * We also know that the frozen data has already fired
948 * its triggers if they exist, so we can clear that too.
949 */
950 if (jh->b_committed_data) {
951 jbd2_free(jh->b_committed_data, bh->b_size);
952 jh->b_committed_data = NULL;
953 if (jh->b_frozen_data) {
954 jh->b_committed_data = jh->b_frozen_data;
955 jh->b_frozen_data = NULL;
956 jh->b_frozen_triggers = NULL;
957 }
958 } else if (jh->b_frozen_data) {
959 jbd2_free(jh->b_frozen_data, bh->b_size);
960 jh->b_frozen_data = NULL;
961 jh->b_frozen_triggers = NULL;
962 }
963
964 spin_lock(&journal->j_list_lock);
965 cp_transaction = jh->b_cp_transaction;
966 if (cp_transaction) {
967 JBUFFER_TRACE(jh, "remove from old cp transaction");
968 cp_transaction->t_chp_stats.cs_dropped++;
969 __jbd2_journal_remove_checkpoint(jh);
970 }
971
972 /* Only re-checkpoint the buffer_head if it is marked
973 * dirty. If the buffer was added to the BJ_Forget list
974 * by jbd2_journal_forget, it may no longer be dirty and
975 * there's no point in keeping a checkpoint record for
976 * it. */
977
978 /*
979 * A buffer which has been freed while still being journaled
980 * by a previous transaction, refile the buffer to BJ_Forget of
981 * the running transaction. If the just committed transaction
982 * contains "add to orphan" operation, we can completely
983 * invalidate the buffer now. We are rather through in that
984 * since the buffer may be still accessible when blocksize <
985 * pagesize and it is attached to the last partial page.
986 */
987 if (buffer_freed(bh) && !jh->b_next_transaction) {
988 struct address_space *mapping;
989
990 clear_buffer_freed(bh);
991 clear_buffer_jbddirty(bh);
992
993 /*
994 * Block device buffers need to stay mapped all the
995 * time, so it is enough to clear buffer_jbddirty and
996 * buffer_freed bits. For the file mapping buffers (i.e.
997 * journalled data) we need to unmap buffer and clear
998 * more bits. We also need to be careful about the check
999 * because the data page mapping can get cleared under
1000 * our hands. Note that if mapping == NULL, we don't
1001 * need to make buffer unmapped because the page is
1002 * already detached from the mapping and buffers cannot
1003 * get reused.
1004 */
1005 mapping = READ_ONCE(bh->b_page->mapping);
1006 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1007 clear_buffer_mapped(bh);
1008 clear_buffer_new(bh);
1009 clear_buffer_req(bh);
1010 bh->b_bdev = NULL;
1011 }
1012 }
1013
1014 if (buffer_jbddirty(bh)) {
1015 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1016 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1017 if (is_journal_aborted(journal))
1018 clear_buffer_jbddirty(bh);
1019 } else {
1020 J_ASSERT_BH(bh, !buffer_dirty(bh));
1021 /*
1022 * The buffer on BJ_Forget list and not jbddirty means
1023 * it has been freed by this transaction and hence it
1024 * could not have been reallocated until this
1025 * transaction has committed. *BUT* it could be
1026 * reallocated once we have written all the data to
1027 * disk and before we process the buffer on BJ_Forget
1028 * list.
1029 */
1030 if (!jh->b_next_transaction)
1031 try_to_free = 1;
1032 }
1033 JBUFFER_TRACE(jh, "refile or unfile buffer");
1034 drop_ref = __jbd2_journal_refile_buffer(jh);
1035 spin_unlock(&jh->b_state_lock);
1036 if (drop_ref)
1037 jbd2_journal_put_journal_head(jh);
1038 if (try_to_free)
1039 release_buffer_page(bh); /* Drops bh reference */
1040 else
1041 __brelse(bh);
1042 cond_resched_lock(&journal->j_list_lock);
1043 }
1044 spin_unlock(&journal->j_list_lock);
1045 /*
1046 * This is a bit sleazy. We use j_list_lock to protect transition
1047 * of a transaction into T_FINISHED state and calling
1048 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1049 * other checkpointing code processing the transaction...
1050 */
1051 write_lock(&journal->j_state_lock);
1052 spin_lock(&journal->j_list_lock);
1053 /*
1054 * Now recheck if some buffers did not get attached to the transaction
1055 * while the lock was dropped...
1056 */
1057 if (commit_transaction->t_forget) {
1058 spin_unlock(&journal->j_list_lock);
1059 write_unlock(&journal->j_state_lock);
1060 goto restart_loop;
1061 }
1062
1063 /* Add the transaction to the checkpoint list
1064 * __journal_remove_checkpoint() can not destroy transaction
1065 * under us because it is not marked as T_FINISHED yet */
1066 if (journal->j_checkpoint_transactions == NULL) {
1067 journal->j_checkpoint_transactions = commit_transaction;
1068 commit_transaction->t_cpnext = commit_transaction;
1069 commit_transaction->t_cpprev = commit_transaction;
1070 } else {
1071 commit_transaction->t_cpnext =
1072 journal->j_checkpoint_transactions;
1073 commit_transaction->t_cpprev =
1074 commit_transaction->t_cpnext->t_cpprev;
1075 commit_transaction->t_cpnext->t_cpprev =
1076 commit_transaction;
1077 commit_transaction->t_cpprev->t_cpnext =
1078 commit_transaction;
1079 }
1080 spin_unlock(&journal->j_list_lock);
1081
1082 /* Done with this transaction! */
1083
1084 jbd_debug(3, "JBD2: commit phase 7\n");
1085
1086 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1087
1088 commit_transaction->t_start = jiffies;
1089 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1090 commit_transaction->t_start);
1091
1092 /*
1093 * File the transaction statistics
1094 */
1095 stats.ts_tid = commit_transaction->t_tid;
1096 stats.run.rs_handle_count =
1097 atomic_read(&commit_transaction->t_handle_count);
1098 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1099 commit_transaction->t_tid, &stats.run);
1100 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1101
1102 commit_transaction->t_state = T_COMMIT_CALLBACK;
1103 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1104 journal->j_commit_sequence = commit_transaction->t_tid;
1105 journal->j_committing_transaction = NULL;
1106 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1107
1108 /*
1109 * weight the commit time higher than the average time so we don't
1110 * react too strongly to vast changes in the commit time
1111 */
1112 if (likely(journal->j_average_commit_time))
1113 journal->j_average_commit_time = (commit_time +
1114 journal->j_average_commit_time*3) / 4;
1115 else
1116 journal->j_average_commit_time = commit_time;
1117
1118 write_unlock(&journal->j_state_lock);
1119
1120 if (journal->j_commit_callback)
1121 journal->j_commit_callback(journal, commit_transaction);
1122
1123 trace_jbd2_end_commit(journal, commit_transaction);
1124 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1125 journal->j_commit_sequence, journal->j_tail_sequence);
1126
1127 write_lock(&journal->j_state_lock);
1128 spin_lock(&journal->j_list_lock);
1129 commit_transaction->t_state = T_FINISHED;
1130 /* Check if the transaction can be dropped now that we are finished */
1131 if (commit_transaction->t_checkpoint_list == NULL &&
1132 commit_transaction->t_checkpoint_io_list == NULL) {
1133 __jbd2_journal_drop_transaction(journal, commit_transaction);
1134 jbd2_journal_free_transaction(commit_transaction);
1135 }
1136 spin_unlock(&journal->j_list_lock);
1137 write_unlock(&journal->j_state_lock);
1138 wake_up(&journal->j_wait_done_commit);
1139
1140 /*
1141 * Calculate overall stats
1142 */
1143 spin_lock(&journal->j_history_lock);
1144 journal->j_stats.ts_tid++;
1145 journal->j_stats.ts_requested += stats.ts_requested;
1146 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1147 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1148 journal->j_stats.run.rs_running += stats.run.rs_running;
1149 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1150 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1151 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1152 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1153 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1154 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1155 spin_unlock(&journal->j_history_lock);
1156}
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 * IO end handler for temporary buffer_heads handling writes to the journal.
34 */
35static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
36{
37 struct buffer_head *orig_bh = bh->b_private;
38
39 BUFFER_TRACE(bh, "");
40 if (uptodate)
41 set_buffer_uptodate(bh);
42 else
43 clear_buffer_uptodate(bh);
44 if (orig_bh) {
45 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
46 smp_mb__after_atomic();
47 wake_up_bit(&orig_bh->b_state, BH_Shadow);
48 }
49 unlock_buffer(bh);
50}
51
52/*
53 * When an ext4 file is truncated, it is possible that some pages are not
54 * successfully freed, because they are attached to a committing transaction.
55 * After the transaction commits, these pages are left on the LRU, with no
56 * ->mapping, and with attached buffers. These pages are trivially reclaimable
57 * by the VM, but their apparent absence upsets the VM accounting, and it makes
58 * the numbers in /proc/meminfo look odd.
59 *
60 * So here, we have a buffer which has just come off the forget list. Look to
61 * see if we can strip all buffers from the backing page.
62 *
63 * Called under lock_journal(), and possibly under journal_datalist_lock. The
64 * caller provided us with a ref against the buffer, and we drop that here.
65 */
66static void release_buffer_page(struct buffer_head *bh)
67{
68 struct page *page;
69
70 if (buffer_dirty(bh))
71 goto nope;
72 if (atomic_read(&bh->b_count) != 1)
73 goto nope;
74 page = bh->b_page;
75 if (!page)
76 goto nope;
77 if (page->mapping)
78 goto nope;
79
80 /* OK, it's a truncated page */
81 if (!trylock_page(page))
82 goto nope;
83
84 get_page(page);
85 __brelse(bh);
86 try_to_free_buffers(page);
87 unlock_page(page);
88 put_page(page);
89 return;
90
91nope:
92 __brelse(bh);
93}
94
95static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
96{
97 struct commit_header *h;
98 __u32 csum;
99
100 if (!jbd2_journal_has_csum_v2or3(j))
101 return;
102
103 h = (struct commit_header *)(bh->b_data);
104 h->h_chksum_type = 0;
105 h->h_chksum_size = 0;
106 h->h_chksum[0] = 0;
107 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
108 h->h_chksum[0] = cpu_to_be32(csum);
109}
110
111/*
112 * Done it all: now submit the commit record. We should have
113 * cleaned up our previous buffers by now, so if we are in abort
114 * mode we can now just skip the rest of the journal write
115 * entirely.
116 *
117 * Returns 1 if the journal needs to be aborted or 0 on success
118 */
119static int journal_submit_commit_record(journal_t *journal,
120 transaction_t *commit_transaction,
121 struct buffer_head **cbh,
122 __u32 crc32_sum)
123{
124 struct commit_header *tmp;
125 struct buffer_head *bh;
126 int ret;
127 struct timespec64 now = current_kernel_time64();
128
129 *cbh = NULL;
130
131 if (is_journal_aborted(journal))
132 return 0;
133
134 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
135 JBD2_COMMIT_BLOCK);
136 if (!bh)
137 return 1;
138
139 tmp = (struct commit_header *)bh->b_data;
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_feature_checksum(journal)) {
144 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
145 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
146 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
147 }
148 jbd2_commit_block_csum_set(journal, bh);
149
150 BUFFER_TRACE(bh, "submit commit block");
151 lock_buffer(bh);
152 clear_buffer_dirty(bh);
153 set_buffer_uptodate(bh);
154 bh->b_end_io = journal_end_buffer_io_sync;
155
156 if (journal->j_flags & JBD2_BARRIER &&
157 !jbd2_has_feature_async_commit(journal))
158 ret = submit_bh(REQ_OP_WRITE,
159 REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh);
160 else
161 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
162
163 *cbh = bh;
164 return ret;
165}
166
167/*
168 * This function along with journal_submit_commit_record
169 * allows to write the commit record asynchronously.
170 */
171static int journal_wait_on_commit_record(journal_t *journal,
172 struct buffer_head *bh)
173{
174 int ret = 0;
175
176 clear_buffer_dirty(bh);
177 wait_on_buffer(bh);
178
179 if (unlikely(!buffer_uptodate(bh)))
180 ret = -EIO;
181 put_bh(bh); /* One for getblk() */
182
183 return ret;
184}
185
186/*
187 * write the filemap data using writepage() address_space_operations.
188 * We don't do block allocation here even for delalloc. We don't
189 * use writepages() because with dealyed allocation we may be doing
190 * block allocation in writepages().
191 */
192static int journal_submit_inode_data_buffers(struct address_space *mapping)
193{
194 int ret;
195 struct writeback_control wbc = {
196 .sync_mode = WB_SYNC_ALL,
197 .nr_to_write = mapping->nrpages * 2,
198 .range_start = 0,
199 .range_end = i_size_read(mapping->host),
200 };
201
202 ret = generic_writepages(mapping, &wbc);
203 return ret;
204}
205
206/*
207 * Submit all the data buffers of inode associated with the transaction to
208 * disk.
209 *
210 * We are in a committing transaction. Therefore no new inode can be added to
211 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
212 * operate on from being released while we write out pages.
213 */
214static int journal_submit_data_buffers(journal_t *journal,
215 transaction_t *commit_transaction)
216{
217 struct jbd2_inode *jinode;
218 int err, ret = 0;
219 struct address_space *mapping;
220
221 spin_lock(&journal->j_list_lock);
222 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
223 if (!(jinode->i_flags & JI_WRITE_DATA))
224 continue;
225 mapping = jinode->i_vfs_inode->i_mapping;
226 jinode->i_flags |= JI_COMMIT_RUNNING;
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 jinode->i_flags &= ~JI_COMMIT_RUNNING;
241 smp_mb();
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 if (!(jinode->i_flags & JI_WAIT_DATA))
263 continue;
264 jinode->i_flags |= JI_COMMIT_RUNNING;
265 spin_unlock(&journal->j_list_lock);
266 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
267 if (err) {
268 /*
269 * Because AS_EIO is cleared by
270 * filemap_fdatawait_range(), set it again so
271 * that user process can get -EIO from fsync().
272 */
273 mapping_set_error(jinode->i_vfs_inode->i_mapping, -EIO);
274
275 if (!ret)
276 ret = err;
277 }
278 spin_lock(&journal->j_list_lock);
279 jinode->i_flags &= ~JI_COMMIT_RUNNING;
280 smp_mb();
281 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
282 }
283
284 /* Now refile inode to proper lists */
285 list_for_each_entry_safe(jinode, next_i,
286 &commit_transaction->t_inode_list, i_list) {
287 list_del(&jinode->i_list);
288 if (jinode->i_next_transaction) {
289 jinode->i_transaction = jinode->i_next_transaction;
290 jinode->i_next_transaction = NULL;
291 list_add(&jinode->i_list,
292 &jinode->i_transaction->t_inode_list);
293 } else {
294 jinode->i_transaction = NULL;
295 }
296 }
297 spin_unlock(&journal->j_list_lock);
298
299 return ret;
300}
301
302static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
303{
304 struct page *page = bh->b_page;
305 char *addr;
306 __u32 checksum;
307
308 addr = kmap_atomic(page);
309 checksum = crc32_be(crc32_sum,
310 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
311 kunmap_atomic(addr);
312
313 return checksum;
314}
315
316static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
317 unsigned long long block)
318{
319 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
320 if (jbd2_has_feature_64bit(j))
321 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
322}
323
324static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
325 struct buffer_head *bh, __u32 sequence)
326{
327 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
328 struct page *page = bh->b_page;
329 __u8 *addr;
330 __u32 csum32;
331 __be32 seq;
332
333 if (!jbd2_journal_has_csum_v2or3(j))
334 return;
335
336 seq = cpu_to_be32(sequence);
337 addr = kmap_atomic(page);
338 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
339 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
340 bh->b_size);
341 kunmap_atomic(addr);
342
343 if (jbd2_has_feature_csum3(j))
344 tag3->t_checksum = cpu_to_be32(csum32);
345 else
346 tag->t_checksum = cpu_to_be16(csum32);
347}
348/*
349 * jbd2_journal_commit_transaction
350 *
351 * The primary function for committing a transaction to the log. This
352 * function is called by the journal thread to begin a complete commit.
353 */
354void jbd2_journal_commit_transaction(journal_t *journal)
355{
356 struct transaction_stats_s stats;
357 transaction_t *commit_transaction;
358 struct journal_head *jh;
359 struct buffer_head *descriptor;
360 struct buffer_head **wbuf = journal->j_wbuf;
361 int bufs;
362 int flags;
363 int err;
364 unsigned long long blocknr;
365 ktime_t start_time;
366 u64 commit_time;
367 char *tagp = NULL;
368 journal_block_tag_t *tag = NULL;
369 int space_left = 0;
370 int first_tag = 0;
371 int tag_flag;
372 int i;
373 int tag_bytes = journal_tag_bytes(journal);
374 struct buffer_head *cbh = NULL; /* For transactional checksums */
375 __u32 crc32_sum = ~0;
376 struct blk_plug plug;
377 /* Tail of the journal */
378 unsigned long first_block;
379 tid_t first_tid;
380 int update_tail;
381 int csum_size = 0;
382 LIST_HEAD(io_bufs);
383 LIST_HEAD(log_bufs);
384
385 if (jbd2_journal_has_csum_v2or3(journal))
386 csum_size = sizeof(struct jbd2_journal_block_tail);
387
388 /*
389 * First job: lock down the current transaction and wait for
390 * all outstanding updates to complete.
391 */
392
393 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
394 if (journal->j_flags & JBD2_FLUSHED) {
395 jbd_debug(3, "super block updated\n");
396 mutex_lock(&journal->j_checkpoint_mutex);
397 /*
398 * We hold j_checkpoint_mutex so tail cannot change under us.
399 * We don't need any special data guarantees for writing sb
400 * since journal is empty and it is ok for write to be
401 * flushed only with transaction commit.
402 */
403 jbd2_journal_update_sb_log_tail(journal,
404 journal->j_tail_sequence,
405 journal->j_tail,
406 REQ_SYNC);
407 mutex_unlock(&journal->j_checkpoint_mutex);
408 } else {
409 jbd_debug(3, "superblock not updated\n");
410 }
411
412 J_ASSERT(journal->j_running_transaction != NULL);
413 J_ASSERT(journal->j_committing_transaction == NULL);
414
415 commit_transaction = journal->j_running_transaction;
416
417 trace_jbd2_start_commit(journal, commit_transaction);
418 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
419 commit_transaction->t_tid);
420
421 write_lock(&journal->j_state_lock);
422 J_ASSERT(commit_transaction->t_state == T_RUNNING);
423 commit_transaction->t_state = T_LOCKED;
424
425 trace_jbd2_commit_locking(journal, commit_transaction);
426 stats.run.rs_wait = commit_transaction->t_max_wait;
427 stats.run.rs_request_delay = 0;
428 stats.run.rs_locked = jiffies;
429 if (commit_transaction->t_requested)
430 stats.run.rs_request_delay =
431 jbd2_time_diff(commit_transaction->t_requested,
432 stats.run.rs_locked);
433 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
434 stats.run.rs_locked);
435
436 spin_lock(&commit_transaction->t_handle_lock);
437 while (atomic_read(&commit_transaction->t_updates)) {
438 DEFINE_WAIT(wait);
439
440 prepare_to_wait(&journal->j_wait_updates, &wait,
441 TASK_UNINTERRUPTIBLE);
442 if (atomic_read(&commit_transaction->t_updates)) {
443 spin_unlock(&commit_transaction->t_handle_lock);
444 write_unlock(&journal->j_state_lock);
445 schedule();
446 write_lock(&journal->j_state_lock);
447 spin_lock(&commit_transaction->t_handle_lock);
448 }
449 finish_wait(&journal->j_wait_updates, &wait);
450 }
451 spin_unlock(&commit_transaction->t_handle_lock);
452
453 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
454 journal->j_max_transaction_buffers);
455
456 /*
457 * First thing we are allowed to do is to discard any remaining
458 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
459 * that there are no such buffers: if a large filesystem
460 * operation like a truncate needs to split itself over multiple
461 * transactions, then it may try to do a jbd2_journal_restart() while
462 * there are still BJ_Reserved buffers outstanding. These must
463 * be released cleanly from the current transaction.
464 *
465 * In this case, the filesystem must still reserve write access
466 * again before modifying the buffer in the new transaction, but
467 * we do not require it to remember exactly which old buffers it
468 * has reserved. This is consistent with the existing behaviour
469 * that multiple jbd2_journal_get_write_access() calls to the same
470 * buffer are perfectly permissible.
471 */
472 while (commit_transaction->t_reserved_list) {
473 jh = commit_transaction->t_reserved_list;
474 JBUFFER_TRACE(jh, "reserved, unused: refile");
475 /*
476 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
477 * leave undo-committed data.
478 */
479 if (jh->b_committed_data) {
480 struct buffer_head *bh = jh2bh(jh);
481
482 jbd_lock_bh_state(bh);
483 jbd2_free(jh->b_committed_data, bh->b_size);
484 jh->b_committed_data = NULL;
485 jbd_unlock_bh_state(bh);
486 }
487 jbd2_journal_refile_buffer(journal, jh);
488 }
489
490 /*
491 * Now try to drop any written-back buffers from the journal's
492 * checkpoint lists. We do this *before* commit because it potentially
493 * frees some memory
494 */
495 spin_lock(&journal->j_list_lock);
496 __jbd2_journal_clean_checkpoint_list(journal, false);
497 spin_unlock(&journal->j_list_lock);
498
499 jbd_debug(3, "JBD2: commit phase 1\n");
500
501 /*
502 * Clear revoked flag to reflect there is no revoked buffers
503 * in the next transaction which is going to be started.
504 */
505 jbd2_clear_buffer_revoked_flags(journal);
506
507 /*
508 * Switch to a new revoke table.
509 */
510 jbd2_journal_switch_revoke_table(journal);
511
512 /*
513 * Reserved credits cannot be claimed anymore, free them
514 */
515 atomic_sub(atomic_read(&journal->j_reserved_credits),
516 &commit_transaction->t_outstanding_credits);
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 2a\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(commit_transaction, &log_bufs);
543
544 jbd_debug(3, "JBD2: commit phase 2b\n");
545
546 /*
547 * Way to go: we have now written out all of the data for a
548 * transaction! Now comes the tricky part: we need to write out
549 * metadata. Loop over the transaction's entire buffer list:
550 */
551 write_lock(&journal->j_state_lock);
552 commit_transaction->t_state = T_COMMIT;
553 write_unlock(&journal->j_state_lock);
554
555 trace_jbd2_commit_logging(journal, commit_transaction);
556 stats.run.rs_logging = jiffies;
557 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
558 stats.run.rs_logging);
559 stats.run.rs_blocks =
560 atomic_read(&commit_transaction->t_outstanding_credits);
561 stats.run.rs_blocks_logged = 0;
562
563 J_ASSERT(commit_transaction->t_nr_buffers <=
564 atomic_read(&commit_transaction->t_outstanding_credits));
565
566 err = 0;
567 bufs = 0;
568 descriptor = NULL;
569 while (commit_transaction->t_buffers) {
570
571 /* Find the next buffer to be journaled... */
572
573 jh = commit_transaction->t_buffers;
574
575 /* If we're in abort mode, we just un-journal the buffer and
576 release it. */
577
578 if (is_journal_aborted(journal)) {
579 clear_buffer_jbddirty(jh2bh(jh));
580 JBUFFER_TRACE(jh, "journal is aborting: refile");
581 jbd2_buffer_abort_trigger(jh,
582 jh->b_frozen_data ?
583 jh->b_frozen_triggers :
584 jh->b_triggers);
585 jbd2_journal_refile_buffer(journal, jh);
586 /* If that was the last one, we need to clean up
587 * any descriptor buffers which may have been
588 * already allocated, even if we are now
589 * aborting. */
590 if (!commit_transaction->t_buffers)
591 goto start_journal_io;
592 continue;
593 }
594
595 /* Make sure we have a descriptor block in which to
596 record the metadata buffer. */
597
598 if (!descriptor) {
599 J_ASSERT (bufs == 0);
600
601 jbd_debug(4, "JBD2: get descriptor\n");
602
603 descriptor = jbd2_journal_get_descriptor_buffer(
604 commit_transaction,
605 JBD2_DESCRIPTOR_BLOCK);
606 if (!descriptor) {
607 jbd2_journal_abort(journal, -EIO);
608 continue;
609 }
610
611 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
612 (unsigned long long)descriptor->b_blocknr,
613 descriptor->b_data);
614 tagp = &descriptor->b_data[sizeof(journal_header_t)];
615 space_left = descriptor->b_size -
616 sizeof(journal_header_t);
617 first_tag = 1;
618 set_buffer_jwrite(descriptor);
619 set_buffer_dirty(descriptor);
620 wbuf[bufs++] = descriptor;
621
622 /* Record it so that we can wait for IO
623 completion later */
624 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
625 jbd2_file_log_bh(&log_bufs, descriptor);
626 }
627
628 /* Where is the buffer to be written? */
629
630 err = jbd2_journal_next_log_block(journal, &blocknr);
631 /* If the block mapping failed, just abandon the buffer
632 and repeat this loop: we'll fall into the
633 refile-on-abort condition above. */
634 if (err) {
635 jbd2_journal_abort(journal, err);
636 continue;
637 }
638
639 /*
640 * start_this_handle() uses t_outstanding_credits to determine
641 * the free space in the log, but this counter is changed
642 * by jbd2_journal_next_log_block() also.
643 */
644 atomic_dec(&commit_transaction->t_outstanding_credits);
645
646 /* Bump b_count to prevent truncate from stumbling over
647 the shadowed buffer! @@@ This can go if we ever get
648 rid of the shadow pairing of buffers. */
649 atomic_inc(&jh2bh(jh)->b_count);
650
651 /*
652 * Make a temporary IO buffer with which to write it out
653 * (this will requeue the metadata buffer to BJ_Shadow).
654 */
655 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
656 JBUFFER_TRACE(jh, "ph3: write metadata");
657 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
658 jh, &wbuf[bufs], blocknr);
659 if (flags < 0) {
660 jbd2_journal_abort(journal, flags);
661 continue;
662 }
663 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
664
665 /* Record the new block's tag in the current descriptor
666 buffer */
667
668 tag_flag = 0;
669 if (flags & 1)
670 tag_flag |= JBD2_FLAG_ESCAPE;
671 if (!first_tag)
672 tag_flag |= JBD2_FLAG_SAME_UUID;
673
674 tag = (journal_block_tag_t *) tagp;
675 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
676 tag->t_flags = cpu_to_be16(tag_flag);
677 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
678 commit_transaction->t_tid);
679 tagp += tag_bytes;
680 space_left -= tag_bytes;
681 bufs++;
682
683 if (first_tag) {
684 memcpy (tagp, journal->j_uuid, 16);
685 tagp += 16;
686 space_left -= 16;
687 first_tag = 0;
688 }
689
690 /* If there's no more to do, or if the descriptor is full,
691 let the IO rip! */
692
693 if (bufs == journal->j_wbufsize ||
694 commit_transaction->t_buffers == NULL ||
695 space_left < tag_bytes + 16 + csum_size) {
696
697 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
698
699 /* Write an end-of-descriptor marker before
700 submitting the IOs. "tag" still points to
701 the last tag we set up. */
702
703 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
704
705 jbd2_descriptor_block_csum_set(journal, descriptor);
706start_journal_io:
707 for (i = 0; i < bufs; i++) {
708 struct buffer_head *bh = wbuf[i];
709 /*
710 * Compute checksum.
711 */
712 if (jbd2_has_feature_checksum(journal)) {
713 crc32_sum =
714 jbd2_checksum_data(crc32_sum, bh);
715 }
716
717 lock_buffer(bh);
718 clear_buffer_dirty(bh);
719 set_buffer_uptodate(bh);
720 bh->b_end_io = journal_end_buffer_io_sync;
721 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
722 }
723 cond_resched();
724 stats.run.rs_blocks_logged += bufs;
725
726 /* Force a new descriptor to be generated next
727 time round the loop. */
728 descriptor = NULL;
729 bufs = 0;
730 }
731 }
732
733 err = journal_finish_inode_data_buffers(journal, commit_transaction);
734 if (err) {
735 printk(KERN_WARNING
736 "JBD2: Detected IO errors while flushing file data "
737 "on %s\n", journal->j_devname);
738 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
739 jbd2_journal_abort(journal, err);
740 err = 0;
741 }
742
743 /*
744 * Get current oldest transaction in the log before we issue flush
745 * to the filesystem device. After the flush we can be sure that
746 * blocks of all older transactions are checkpointed to persistent
747 * storage and we will be safe to update journal start in the
748 * superblock with the numbers we get here.
749 */
750 update_tail =
751 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
752
753 write_lock(&journal->j_state_lock);
754 if (update_tail) {
755 long freed = first_block - journal->j_tail;
756
757 if (first_block < journal->j_tail)
758 freed += journal->j_last - journal->j_first;
759 /* Update tail only if we free significant amount of space */
760 if (freed < journal->j_maxlen / 4)
761 update_tail = 0;
762 }
763 J_ASSERT(commit_transaction->t_state == T_COMMIT);
764 commit_transaction->t_state = T_COMMIT_DFLUSH;
765 write_unlock(&journal->j_state_lock);
766
767 /*
768 * If the journal is not located on the file system device,
769 * then we must flush the file system device before we issue
770 * the commit record
771 */
772 if (commit_transaction->t_need_data_flush &&
773 (journal->j_fs_dev != journal->j_dev) &&
774 (journal->j_flags & JBD2_BARRIER))
775 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
776
777 /* Done it all: now write the commit record asynchronously. */
778 if (jbd2_has_feature_async_commit(journal)) {
779 err = journal_submit_commit_record(journal, commit_transaction,
780 &cbh, crc32_sum);
781 if (err)
782 __jbd2_journal_abort_hard(journal);
783 }
784
785 blk_finish_plug(&plug);
786
787 /* Lo and behold: we have just managed to send a transaction to
788 the log. Before we can commit it, wait for the IO so far to
789 complete. Control buffers being written are on the
790 transaction's t_log_list queue, and metadata buffers are on
791 the io_bufs list.
792
793 Wait for the buffers in reverse order. That way we are
794 less likely to be woken up until all IOs have completed, and
795 so we incur less scheduling load.
796 */
797
798 jbd_debug(3, "JBD2: commit phase 3\n");
799
800 while (!list_empty(&io_bufs)) {
801 struct buffer_head *bh = list_entry(io_bufs.prev,
802 struct buffer_head,
803 b_assoc_buffers);
804
805 wait_on_buffer(bh);
806 cond_resched();
807
808 if (unlikely(!buffer_uptodate(bh)))
809 err = -EIO;
810 jbd2_unfile_log_bh(bh);
811
812 /*
813 * The list contains temporary buffer heads created by
814 * jbd2_journal_write_metadata_buffer().
815 */
816 BUFFER_TRACE(bh, "dumping temporary bh");
817 __brelse(bh);
818 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
819 free_buffer_head(bh);
820
821 /* We also have to refile the corresponding shadowed buffer */
822 jh = commit_transaction->t_shadow_list->b_tprev;
823 bh = jh2bh(jh);
824 clear_buffer_jwrite(bh);
825 J_ASSERT_BH(bh, buffer_jbddirty(bh));
826 J_ASSERT_BH(bh, !buffer_shadow(bh));
827
828 /* The metadata is now released for reuse, but we need
829 to remember it against this transaction so that when
830 we finally commit, we can do any checkpointing
831 required. */
832 JBUFFER_TRACE(jh, "file as BJ_Forget");
833 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
834 JBUFFER_TRACE(jh, "brelse shadowed buffer");
835 __brelse(bh);
836 }
837
838 J_ASSERT (commit_transaction->t_shadow_list == NULL);
839
840 jbd_debug(3, "JBD2: commit phase 4\n");
841
842 /* Here we wait for the revoke record and descriptor record buffers */
843 while (!list_empty(&log_bufs)) {
844 struct buffer_head *bh;
845
846 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
847 wait_on_buffer(bh);
848 cond_resched();
849
850 if (unlikely(!buffer_uptodate(bh)))
851 err = -EIO;
852
853 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
854 clear_buffer_jwrite(bh);
855 jbd2_unfile_log_bh(bh);
856 __brelse(bh); /* One for getblk */
857 /* AKPM: bforget here */
858 }
859
860 if (err)
861 jbd2_journal_abort(journal, err);
862
863 jbd_debug(3, "JBD2: commit phase 5\n");
864 write_lock(&journal->j_state_lock);
865 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
866 commit_transaction->t_state = T_COMMIT_JFLUSH;
867 write_unlock(&journal->j_state_lock);
868
869 if (!jbd2_has_feature_async_commit(journal)) {
870 err = journal_submit_commit_record(journal, commit_transaction,
871 &cbh, crc32_sum);
872 if (err)
873 __jbd2_journal_abort_hard(journal);
874 }
875 if (cbh)
876 err = journal_wait_on_commit_record(journal, cbh);
877 if (jbd2_has_feature_async_commit(journal) &&
878 journal->j_flags & JBD2_BARRIER) {
879 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
880 }
881
882 if (err)
883 jbd2_journal_abort(journal, err);
884
885 /*
886 * Now disk caches for filesystem device are flushed so we are safe to
887 * erase checkpointed transactions from the log by updating journal
888 * superblock.
889 */
890 if (update_tail)
891 jbd2_update_log_tail(journal, first_tid, first_block);
892
893 /* End of a transaction! Finally, we can do checkpoint
894 processing: any buffers committed as a result of this
895 transaction can be removed from any checkpoint list it was on
896 before. */
897
898 jbd_debug(3, "JBD2: commit phase 6\n");
899
900 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
901 J_ASSERT(commit_transaction->t_buffers == NULL);
902 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
903 J_ASSERT(commit_transaction->t_shadow_list == NULL);
904
905restart_loop:
906 /*
907 * As there are other places (journal_unmap_buffer()) adding buffers
908 * to this list we have to be careful and hold the j_list_lock.
909 */
910 spin_lock(&journal->j_list_lock);
911 while (commit_transaction->t_forget) {
912 transaction_t *cp_transaction;
913 struct buffer_head *bh;
914 int try_to_free = 0;
915
916 jh = commit_transaction->t_forget;
917 spin_unlock(&journal->j_list_lock);
918 bh = jh2bh(jh);
919 /*
920 * Get a reference so that bh cannot be freed before we are
921 * done with it.
922 */
923 get_bh(bh);
924 jbd_lock_bh_state(bh);
925 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
926
927 /*
928 * If there is undo-protected committed data against
929 * this buffer, then we can remove it now. If it is a
930 * buffer needing such protection, the old frozen_data
931 * field now points to a committed version of the
932 * buffer, so rotate that field to the new committed
933 * data.
934 *
935 * Otherwise, we can just throw away the frozen data now.
936 *
937 * We also know that the frozen data has already fired
938 * its triggers if they exist, so we can clear that too.
939 */
940 if (jh->b_committed_data) {
941 jbd2_free(jh->b_committed_data, bh->b_size);
942 jh->b_committed_data = NULL;
943 if (jh->b_frozen_data) {
944 jh->b_committed_data = jh->b_frozen_data;
945 jh->b_frozen_data = NULL;
946 jh->b_frozen_triggers = NULL;
947 }
948 } else if (jh->b_frozen_data) {
949 jbd2_free(jh->b_frozen_data, bh->b_size);
950 jh->b_frozen_data = NULL;
951 jh->b_frozen_triggers = NULL;
952 }
953
954 spin_lock(&journal->j_list_lock);
955 cp_transaction = jh->b_cp_transaction;
956 if (cp_transaction) {
957 JBUFFER_TRACE(jh, "remove from old cp transaction");
958 cp_transaction->t_chp_stats.cs_dropped++;
959 __jbd2_journal_remove_checkpoint(jh);
960 }
961
962 /* Only re-checkpoint the buffer_head if it is marked
963 * dirty. If the buffer was added to the BJ_Forget list
964 * by jbd2_journal_forget, it may no longer be dirty and
965 * there's no point in keeping a checkpoint record for
966 * it. */
967
968 /*
969 * A buffer which has been freed while still being journaled by
970 * a previous transaction.
971 */
972 if (buffer_freed(bh)) {
973 /*
974 * If the running transaction is the one containing
975 * "add to orphan" operation (b_next_transaction !=
976 * NULL), we have to wait for that transaction to
977 * commit before we can really get rid of the buffer.
978 * So just clear b_modified to not confuse transaction
979 * credit accounting and refile the buffer to
980 * BJ_Forget of the running transaction. If the just
981 * committed transaction contains "add to orphan"
982 * operation, we can completely invalidate the buffer
983 * now. We are rather through in that since the
984 * buffer may be still accessible when blocksize <
985 * pagesize and it is attached to the last partial
986 * page.
987 */
988 jh->b_modified = 0;
989 if (!jh->b_next_transaction) {
990 clear_buffer_freed(bh);
991 clear_buffer_jbddirty(bh);
992 clear_buffer_mapped(bh);
993 clear_buffer_new(bh);
994 clear_buffer_req(bh);
995 bh->b_bdev = NULL;
996 }
997 }
998
999 if (buffer_jbddirty(bh)) {
1000 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1001 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1002 if (is_journal_aborted(journal))
1003 clear_buffer_jbddirty(bh);
1004 } else {
1005 J_ASSERT_BH(bh, !buffer_dirty(bh));
1006 /*
1007 * The buffer on BJ_Forget list and not jbddirty means
1008 * it has been freed by this transaction and hence it
1009 * could not have been reallocated until this
1010 * transaction has committed. *BUT* it could be
1011 * reallocated once we have written all the data to
1012 * disk and before we process the buffer on BJ_Forget
1013 * list.
1014 */
1015 if (!jh->b_next_transaction)
1016 try_to_free = 1;
1017 }
1018 JBUFFER_TRACE(jh, "refile or unfile buffer");
1019 __jbd2_journal_refile_buffer(jh);
1020 jbd_unlock_bh_state(bh);
1021 if (try_to_free)
1022 release_buffer_page(bh); /* Drops bh reference */
1023 else
1024 __brelse(bh);
1025 cond_resched_lock(&journal->j_list_lock);
1026 }
1027 spin_unlock(&journal->j_list_lock);
1028 /*
1029 * This is a bit sleazy. We use j_list_lock to protect transition
1030 * of a transaction into T_FINISHED state and calling
1031 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1032 * other checkpointing code processing the transaction...
1033 */
1034 write_lock(&journal->j_state_lock);
1035 spin_lock(&journal->j_list_lock);
1036 /*
1037 * Now recheck if some buffers did not get attached to the transaction
1038 * while the lock was dropped...
1039 */
1040 if (commit_transaction->t_forget) {
1041 spin_unlock(&journal->j_list_lock);
1042 write_unlock(&journal->j_state_lock);
1043 goto restart_loop;
1044 }
1045
1046 /* Add the transaction to the checkpoint list
1047 * __journal_remove_checkpoint() can not destroy transaction
1048 * under us because it is not marked as T_FINISHED yet */
1049 if (journal->j_checkpoint_transactions == NULL) {
1050 journal->j_checkpoint_transactions = commit_transaction;
1051 commit_transaction->t_cpnext = commit_transaction;
1052 commit_transaction->t_cpprev = commit_transaction;
1053 } else {
1054 commit_transaction->t_cpnext =
1055 journal->j_checkpoint_transactions;
1056 commit_transaction->t_cpprev =
1057 commit_transaction->t_cpnext->t_cpprev;
1058 commit_transaction->t_cpnext->t_cpprev =
1059 commit_transaction;
1060 commit_transaction->t_cpprev->t_cpnext =
1061 commit_transaction;
1062 }
1063 spin_unlock(&journal->j_list_lock);
1064
1065 /* Done with this transaction! */
1066
1067 jbd_debug(3, "JBD2: commit phase 7\n");
1068
1069 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1070
1071 commit_transaction->t_start = jiffies;
1072 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1073 commit_transaction->t_start);
1074
1075 /*
1076 * File the transaction statistics
1077 */
1078 stats.ts_tid = commit_transaction->t_tid;
1079 stats.run.rs_handle_count =
1080 atomic_read(&commit_transaction->t_handle_count);
1081 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1082 commit_transaction->t_tid, &stats.run);
1083 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1084
1085 commit_transaction->t_state = T_COMMIT_CALLBACK;
1086 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1087 journal->j_commit_sequence = commit_transaction->t_tid;
1088 journal->j_committing_transaction = NULL;
1089 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1090
1091 /*
1092 * weight the commit time higher than the average time so we don't
1093 * react too strongly to vast changes in the commit time
1094 */
1095 if (likely(journal->j_average_commit_time))
1096 journal->j_average_commit_time = (commit_time +
1097 journal->j_average_commit_time*3) / 4;
1098 else
1099 journal->j_average_commit_time = commit_time;
1100
1101 write_unlock(&journal->j_state_lock);
1102
1103 if (journal->j_commit_callback)
1104 journal->j_commit_callback(journal, commit_transaction);
1105
1106 trace_jbd2_end_commit(journal, commit_transaction);
1107 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1108 journal->j_commit_sequence, journal->j_tail_sequence);
1109
1110 write_lock(&journal->j_state_lock);
1111 spin_lock(&journal->j_list_lock);
1112 commit_transaction->t_state = T_FINISHED;
1113 /* Check if the transaction can be dropped now that we are finished */
1114 if (commit_transaction->t_checkpoint_list == NULL &&
1115 commit_transaction->t_checkpoint_io_list == NULL) {
1116 __jbd2_journal_drop_transaction(journal, commit_transaction);
1117 jbd2_journal_free_transaction(commit_transaction);
1118 }
1119 spin_unlock(&journal->j_list_lock);
1120 write_unlock(&journal->j_state_lock);
1121 wake_up(&journal->j_wait_done_commit);
1122
1123 /*
1124 * Calculate overall stats
1125 */
1126 spin_lock(&journal->j_history_lock);
1127 journal->j_stats.ts_tid++;
1128 journal->j_stats.ts_requested += stats.ts_requested;
1129 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1130 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1131 journal->j_stats.run.rs_running += stats.run.rs_running;
1132 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1133 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1134 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1135 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1136 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1137 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1138 spin_unlock(&journal->j_history_lock);
1139}