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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 folio *folio;
66 struct page *page;
67
68 if (buffer_dirty(bh))
69 goto nope;
70 if (atomic_read(&bh->b_count) != 1)
71 goto nope;
72 page = bh->b_page;
73 if (!page)
74 goto nope;
75 folio = page_folio(page);
76 if (folio->mapping)
77 goto nope;
78
79 /* OK, it's a truncated page */
80 if (!folio_trylock(folio))
81 goto nope;
82
83 folio_get(folio);
84 __brelse(bh);
85 try_to_free_buffers(folio);
86 folio_unlock(folio);
87 folio_put(folio);
88 return;
89
90nope:
91 __brelse(bh);
92}
93
94static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
95{
96 struct commit_header *h;
97 __u32 csum;
98
99 if (!jbd2_journal_has_csum_v2or3(j))
100 return;
101
102 h = (struct commit_header *)(bh->b_data);
103 h->h_chksum_type = 0;
104 h->h_chksum_size = 0;
105 h->h_chksum[0] = 0;
106 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
107 h->h_chksum[0] = cpu_to_be32(csum);
108}
109
110/*
111 * Done it all: now submit the commit record. We should have
112 * cleaned up our previous buffers by now, so if we are in abort
113 * mode we can now just skip the rest of the journal write
114 * entirely.
115 *
116 * Returns 1 if the journal needs to be aborted or 0 on success
117 */
118static int journal_submit_commit_record(journal_t *journal,
119 transaction_t *commit_transaction,
120 struct buffer_head **cbh,
121 __u32 crc32_sum)
122{
123 struct commit_header *tmp;
124 struct buffer_head *bh;
125 struct timespec64 now;
126 blk_opf_t write_flags = REQ_OP_WRITE | REQ_SYNC;
127
128 *cbh = NULL;
129
130 if (is_journal_aborted(journal))
131 return 0;
132
133 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
134 JBD2_COMMIT_BLOCK);
135 if (!bh)
136 return 1;
137
138 tmp = (struct commit_header *)bh->b_data;
139 ktime_get_coarse_real_ts64(&now);
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 write_flags |= REQ_PREFLUSH | REQ_FUA;
159
160 submit_bh(write_flags, bh);
161 *cbh = bh;
162 return 0;
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 */
190int jbd2_journal_submit_inode_data_buffers(struct jbd2_inode *jinode)
191{
192 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
193 struct writeback_control wbc = {
194 .sync_mode = WB_SYNC_ALL,
195 .nr_to_write = mapping->nrpages * 2,
196 .range_start = jinode->i_dirty_start,
197 .range_end = jinode->i_dirty_end,
198 };
199
200 /*
201 * submit the inode data buffers. We use writepage
202 * instead of writepages. Because writepages can do
203 * block allocation with delalloc. We need to write
204 * only allocated blocks here.
205 */
206 return generic_writepages(mapping, &wbc);
207}
208
209/* Send all the data buffers related to an inode */
210int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode)
211{
212 if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
213 return 0;
214
215 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
216 return journal->j_submit_inode_data_buffers(jinode);
217
218}
219EXPORT_SYMBOL(jbd2_submit_inode_data);
220
221int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
222{
223 if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
224 !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
225 return 0;
226 return filemap_fdatawait_range_keep_errors(
227 jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
228 jinode->i_dirty_end);
229}
230EXPORT_SYMBOL(jbd2_wait_inode_data);
231
232/*
233 * Submit all the data buffers of inode associated with the transaction to
234 * disk.
235 *
236 * We are in a committing transaction. Therefore no new inode can be added to
237 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
238 * operate on from being released while we write out pages.
239 */
240static int journal_submit_data_buffers(journal_t *journal,
241 transaction_t *commit_transaction)
242{
243 struct jbd2_inode *jinode;
244 int err, ret = 0;
245
246 spin_lock(&journal->j_list_lock);
247 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
248 if (!(jinode->i_flags & JI_WRITE_DATA))
249 continue;
250 jinode->i_flags |= JI_COMMIT_RUNNING;
251 spin_unlock(&journal->j_list_lock);
252 /* submit the inode data buffers. */
253 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
254 if (journal->j_submit_inode_data_buffers) {
255 err = journal->j_submit_inode_data_buffers(jinode);
256 if (!ret)
257 ret = err;
258 }
259 spin_lock(&journal->j_list_lock);
260 J_ASSERT(jinode->i_transaction == commit_transaction);
261 jinode->i_flags &= ~JI_COMMIT_RUNNING;
262 smp_mb();
263 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
264 }
265 spin_unlock(&journal->j_list_lock);
266 return ret;
267}
268
269int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
270{
271 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
272
273 return filemap_fdatawait_range_keep_errors(mapping,
274 jinode->i_dirty_start,
275 jinode->i_dirty_end);
276}
277
278/*
279 * Wait for data submitted for writeout, refile inodes to proper
280 * transaction if needed.
281 *
282 */
283static int journal_finish_inode_data_buffers(journal_t *journal,
284 transaction_t *commit_transaction)
285{
286 struct jbd2_inode *jinode, *next_i;
287 int err, ret = 0;
288
289 /* For locking, see the comment in journal_submit_data_buffers() */
290 spin_lock(&journal->j_list_lock);
291 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
292 if (!(jinode->i_flags & JI_WAIT_DATA))
293 continue;
294 jinode->i_flags |= JI_COMMIT_RUNNING;
295 spin_unlock(&journal->j_list_lock);
296 /* wait for the inode data buffers writeout. */
297 if (journal->j_finish_inode_data_buffers) {
298 err = journal->j_finish_inode_data_buffers(jinode);
299 if (!ret)
300 ret = err;
301 }
302 spin_lock(&journal->j_list_lock);
303 jinode->i_flags &= ~JI_COMMIT_RUNNING;
304 smp_mb();
305 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
306 }
307
308 /* Now refile inode to proper lists */
309 list_for_each_entry_safe(jinode, next_i,
310 &commit_transaction->t_inode_list, i_list) {
311 list_del(&jinode->i_list);
312 if (jinode->i_next_transaction) {
313 jinode->i_transaction = jinode->i_next_transaction;
314 jinode->i_next_transaction = NULL;
315 list_add(&jinode->i_list,
316 &jinode->i_transaction->t_inode_list);
317 } else {
318 jinode->i_transaction = NULL;
319 jinode->i_dirty_start = 0;
320 jinode->i_dirty_end = 0;
321 }
322 }
323 spin_unlock(&journal->j_list_lock);
324
325 return ret;
326}
327
328static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
329{
330 struct page *page = bh->b_page;
331 char *addr;
332 __u32 checksum;
333
334 addr = kmap_atomic(page);
335 checksum = crc32_be(crc32_sum,
336 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
337 kunmap_atomic(addr);
338
339 return checksum;
340}
341
342static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
343 unsigned long long block)
344{
345 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
346 if (jbd2_has_feature_64bit(j))
347 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
348}
349
350static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
351 struct buffer_head *bh, __u32 sequence)
352{
353 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
354 struct page *page = bh->b_page;
355 __u8 *addr;
356 __u32 csum32;
357 __be32 seq;
358
359 if (!jbd2_journal_has_csum_v2or3(j))
360 return;
361
362 seq = cpu_to_be32(sequence);
363 addr = kmap_atomic(page);
364 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
365 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
366 bh->b_size);
367 kunmap_atomic(addr);
368
369 if (jbd2_has_feature_csum3(j))
370 tag3->t_checksum = cpu_to_be32(csum32);
371 else
372 tag->t_checksum = cpu_to_be16(csum32);
373}
374/*
375 * jbd2_journal_commit_transaction
376 *
377 * The primary function for committing a transaction to the log. This
378 * function is called by the journal thread to begin a complete commit.
379 */
380void jbd2_journal_commit_transaction(journal_t *journal)
381{
382 struct transaction_stats_s stats;
383 transaction_t *commit_transaction;
384 struct journal_head *jh;
385 struct buffer_head *descriptor;
386 struct buffer_head **wbuf = journal->j_wbuf;
387 int bufs;
388 int flags;
389 int err;
390 unsigned long long blocknr;
391 ktime_t start_time;
392 u64 commit_time;
393 char *tagp = NULL;
394 journal_block_tag_t *tag = NULL;
395 int space_left = 0;
396 int first_tag = 0;
397 int tag_flag;
398 int i;
399 int tag_bytes = journal_tag_bytes(journal);
400 struct buffer_head *cbh = NULL; /* For transactional checksums */
401 __u32 crc32_sum = ~0;
402 struct blk_plug plug;
403 /* Tail of the journal */
404 unsigned long first_block;
405 tid_t first_tid;
406 int update_tail;
407 int csum_size = 0;
408 LIST_HEAD(io_bufs);
409 LIST_HEAD(log_bufs);
410
411 if (jbd2_journal_has_csum_v2or3(journal))
412 csum_size = sizeof(struct jbd2_journal_block_tail);
413
414 /*
415 * First job: lock down the current transaction and wait for
416 * all outstanding updates to complete.
417 */
418
419 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
420 if (journal->j_flags & JBD2_FLUSHED) {
421 jbd2_debug(3, "super block updated\n");
422 mutex_lock_io(&journal->j_checkpoint_mutex);
423 /*
424 * We hold j_checkpoint_mutex so tail cannot change under us.
425 * We don't need any special data guarantees for writing sb
426 * since journal is empty and it is ok for write to be
427 * flushed only with transaction commit.
428 */
429 jbd2_journal_update_sb_log_tail(journal,
430 journal->j_tail_sequence,
431 journal->j_tail,
432 REQ_SYNC);
433 mutex_unlock(&journal->j_checkpoint_mutex);
434 } else {
435 jbd2_debug(3, "superblock not updated\n");
436 }
437
438 J_ASSERT(journal->j_running_transaction != NULL);
439 J_ASSERT(journal->j_committing_transaction == NULL);
440
441 write_lock(&journal->j_state_lock);
442 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
443 while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
444 DEFINE_WAIT(wait);
445
446 prepare_to_wait(&journal->j_fc_wait, &wait,
447 TASK_UNINTERRUPTIBLE);
448 write_unlock(&journal->j_state_lock);
449 schedule();
450 write_lock(&journal->j_state_lock);
451 finish_wait(&journal->j_fc_wait, &wait);
452 /*
453 * TODO: by blocking fast commits here, we are increasing
454 * fsync() latency slightly. Strictly speaking, we don't need
455 * to block fast commits until the transaction enters T_FLUSH
456 * state. So an optimization is possible where we block new fast
457 * commits here and wait for existing ones to complete
458 * just before we enter T_FLUSH. That way, the existing fast
459 * commits and this full commit can proceed parallely.
460 */
461 }
462 write_unlock(&journal->j_state_lock);
463
464 commit_transaction = journal->j_running_transaction;
465
466 trace_jbd2_start_commit(journal, commit_transaction);
467 jbd2_debug(1, "JBD2: starting commit of transaction %d\n",
468 commit_transaction->t_tid);
469
470 write_lock(&journal->j_state_lock);
471 journal->j_fc_off = 0;
472 J_ASSERT(commit_transaction->t_state == T_RUNNING);
473 commit_transaction->t_state = T_LOCKED;
474
475 trace_jbd2_commit_locking(journal, commit_transaction);
476 stats.run.rs_wait = commit_transaction->t_max_wait;
477 stats.run.rs_request_delay = 0;
478 stats.run.rs_locked = jiffies;
479 if (commit_transaction->t_requested)
480 stats.run.rs_request_delay =
481 jbd2_time_diff(commit_transaction->t_requested,
482 stats.run.rs_locked);
483 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
484 stats.run.rs_locked);
485
486 // waits for any t_updates to finish
487 jbd2_journal_wait_updates(journal);
488
489 commit_transaction->t_state = T_SWITCH;
490
491 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
492 journal->j_max_transaction_buffers);
493
494 /*
495 * First thing we are allowed to do is to discard any remaining
496 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
497 * that there are no such buffers: if a large filesystem
498 * operation like a truncate needs to split itself over multiple
499 * transactions, then it may try to do a jbd2_journal_restart() while
500 * there are still BJ_Reserved buffers outstanding. These must
501 * be released cleanly from the current transaction.
502 *
503 * In this case, the filesystem must still reserve write access
504 * again before modifying the buffer in the new transaction, but
505 * we do not require it to remember exactly which old buffers it
506 * has reserved. This is consistent with the existing behaviour
507 * that multiple jbd2_journal_get_write_access() calls to the same
508 * buffer are perfectly permissible.
509 * We use journal->j_state_lock here to serialize processing of
510 * t_reserved_list with eviction of buffers from journal_unmap_buffer().
511 */
512 while (commit_transaction->t_reserved_list) {
513 jh = commit_transaction->t_reserved_list;
514 JBUFFER_TRACE(jh, "reserved, unused: refile");
515 /*
516 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
517 * leave undo-committed data.
518 */
519 if (jh->b_committed_data) {
520 struct buffer_head *bh = jh2bh(jh);
521
522 spin_lock(&jh->b_state_lock);
523 jbd2_free(jh->b_committed_data, bh->b_size);
524 jh->b_committed_data = NULL;
525 spin_unlock(&jh->b_state_lock);
526 }
527 jbd2_journal_refile_buffer(journal, jh);
528 }
529
530 write_unlock(&journal->j_state_lock);
531 /*
532 * Now try to drop any written-back buffers from the journal's
533 * checkpoint lists. We do this *before* commit because it potentially
534 * frees some memory
535 */
536 spin_lock(&journal->j_list_lock);
537 __jbd2_journal_clean_checkpoint_list(journal, false);
538 spin_unlock(&journal->j_list_lock);
539
540 jbd2_debug(3, "JBD2: commit phase 1\n");
541
542 /*
543 * Clear revoked flag to reflect there is no revoked buffers
544 * in the next transaction which is going to be started.
545 */
546 jbd2_clear_buffer_revoked_flags(journal);
547
548 /*
549 * Switch to a new revoke table.
550 */
551 jbd2_journal_switch_revoke_table(journal);
552
553 write_lock(&journal->j_state_lock);
554 /*
555 * Reserved credits cannot be claimed anymore, free them
556 */
557 atomic_sub(atomic_read(&journal->j_reserved_credits),
558 &commit_transaction->t_outstanding_credits);
559
560 trace_jbd2_commit_flushing(journal, commit_transaction);
561 stats.run.rs_flushing = jiffies;
562 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
563 stats.run.rs_flushing);
564
565 commit_transaction->t_state = T_FLUSH;
566 journal->j_committing_transaction = commit_transaction;
567 journal->j_running_transaction = NULL;
568 start_time = ktime_get();
569 commit_transaction->t_log_start = journal->j_head;
570 wake_up_all(&journal->j_wait_transaction_locked);
571 write_unlock(&journal->j_state_lock);
572
573 jbd2_debug(3, "JBD2: commit phase 2a\n");
574
575 /*
576 * Now start flushing things to disk, in the order they appear
577 * on the transaction lists. Data blocks go first.
578 */
579 err = journal_submit_data_buffers(journal, commit_transaction);
580 if (err)
581 jbd2_journal_abort(journal, err);
582
583 blk_start_plug(&plug);
584 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
585
586 jbd2_debug(3, "JBD2: commit phase 2b\n");
587
588 /*
589 * Way to go: we have now written out all of the data for a
590 * transaction! Now comes the tricky part: we need to write out
591 * metadata. Loop over the transaction's entire buffer list:
592 */
593 write_lock(&journal->j_state_lock);
594 commit_transaction->t_state = T_COMMIT;
595 write_unlock(&journal->j_state_lock);
596
597 trace_jbd2_commit_logging(journal, commit_transaction);
598 stats.run.rs_logging = jiffies;
599 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
600 stats.run.rs_logging);
601 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
602 stats.run.rs_blocks_logged = 0;
603
604 J_ASSERT(commit_transaction->t_nr_buffers <=
605 atomic_read(&commit_transaction->t_outstanding_credits));
606
607 err = 0;
608 bufs = 0;
609 descriptor = NULL;
610 while (commit_transaction->t_buffers) {
611
612 /* Find the next buffer to be journaled... */
613
614 jh = commit_transaction->t_buffers;
615
616 /* If we're in abort mode, we just un-journal the buffer and
617 release it. */
618
619 if (is_journal_aborted(journal)) {
620 clear_buffer_jbddirty(jh2bh(jh));
621 JBUFFER_TRACE(jh, "journal is aborting: refile");
622 jbd2_buffer_abort_trigger(jh,
623 jh->b_frozen_data ?
624 jh->b_frozen_triggers :
625 jh->b_triggers);
626 jbd2_journal_refile_buffer(journal, jh);
627 /* If that was the last one, we need to clean up
628 * any descriptor buffers which may have been
629 * already allocated, even if we are now
630 * aborting. */
631 if (!commit_transaction->t_buffers)
632 goto start_journal_io;
633 continue;
634 }
635
636 /* Make sure we have a descriptor block in which to
637 record the metadata buffer. */
638
639 if (!descriptor) {
640 J_ASSERT (bufs == 0);
641
642 jbd2_debug(4, "JBD2: get descriptor\n");
643
644 descriptor = jbd2_journal_get_descriptor_buffer(
645 commit_transaction,
646 JBD2_DESCRIPTOR_BLOCK);
647 if (!descriptor) {
648 jbd2_journal_abort(journal, -EIO);
649 continue;
650 }
651
652 jbd2_debug(4, "JBD2: got buffer %llu (%p)\n",
653 (unsigned long long)descriptor->b_blocknr,
654 descriptor->b_data);
655 tagp = &descriptor->b_data[sizeof(journal_header_t)];
656 space_left = descriptor->b_size -
657 sizeof(journal_header_t);
658 first_tag = 1;
659 set_buffer_jwrite(descriptor);
660 set_buffer_dirty(descriptor);
661 wbuf[bufs++] = descriptor;
662
663 /* Record it so that we can wait for IO
664 completion later */
665 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
666 jbd2_file_log_bh(&log_bufs, descriptor);
667 }
668
669 /* Where is the buffer to be written? */
670
671 err = jbd2_journal_next_log_block(journal, &blocknr);
672 /* If the block mapping failed, just abandon the buffer
673 and repeat this loop: we'll fall into the
674 refile-on-abort condition above. */
675 if (err) {
676 jbd2_journal_abort(journal, err);
677 continue;
678 }
679
680 /*
681 * start_this_handle() uses t_outstanding_credits to determine
682 * the free space in the log.
683 */
684 atomic_dec(&commit_transaction->t_outstanding_credits);
685
686 /* Bump b_count to prevent truncate from stumbling over
687 the shadowed buffer! @@@ This can go if we ever get
688 rid of the shadow pairing of buffers. */
689 atomic_inc(&jh2bh(jh)->b_count);
690
691 /*
692 * Make a temporary IO buffer with which to write it out
693 * (this will requeue the metadata buffer to BJ_Shadow).
694 */
695 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
696 JBUFFER_TRACE(jh, "ph3: write metadata");
697 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
698 jh, &wbuf[bufs], blocknr);
699 if (flags < 0) {
700 jbd2_journal_abort(journal, flags);
701 continue;
702 }
703 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
704
705 /* Record the new block's tag in the current descriptor
706 buffer */
707
708 tag_flag = 0;
709 if (flags & 1)
710 tag_flag |= JBD2_FLAG_ESCAPE;
711 if (!first_tag)
712 tag_flag |= JBD2_FLAG_SAME_UUID;
713
714 tag = (journal_block_tag_t *) tagp;
715 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
716 tag->t_flags = cpu_to_be16(tag_flag);
717 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
718 commit_transaction->t_tid);
719 tagp += tag_bytes;
720 space_left -= tag_bytes;
721 bufs++;
722
723 if (first_tag) {
724 memcpy (tagp, journal->j_uuid, 16);
725 tagp += 16;
726 space_left -= 16;
727 first_tag = 0;
728 }
729
730 /* If there's no more to do, or if the descriptor is full,
731 let the IO rip! */
732
733 if (bufs == journal->j_wbufsize ||
734 commit_transaction->t_buffers == NULL ||
735 space_left < tag_bytes + 16 + csum_size) {
736
737 jbd2_debug(4, "JBD2: Submit %d IOs\n", bufs);
738
739 /* Write an end-of-descriptor marker before
740 submitting the IOs. "tag" still points to
741 the last tag we set up. */
742
743 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
744start_journal_io:
745 if (descriptor)
746 jbd2_descriptor_block_csum_set(journal,
747 descriptor);
748
749 for (i = 0; i < bufs; i++) {
750 struct buffer_head *bh = wbuf[i];
751 /*
752 * Compute checksum.
753 */
754 if (jbd2_has_feature_checksum(journal)) {
755 crc32_sum =
756 jbd2_checksum_data(crc32_sum, bh);
757 }
758
759 lock_buffer(bh);
760 clear_buffer_dirty(bh);
761 set_buffer_uptodate(bh);
762 bh->b_end_io = journal_end_buffer_io_sync;
763 submit_bh(REQ_OP_WRITE | REQ_SYNC, bh);
764 }
765 cond_resched();
766
767 /* Force a new descriptor to be generated next
768 time round the loop. */
769 descriptor = NULL;
770 bufs = 0;
771 }
772 }
773
774 err = journal_finish_inode_data_buffers(journal, commit_transaction);
775 if (err) {
776 printk(KERN_WARNING
777 "JBD2: Detected IO errors while flushing file data "
778 "on %s\n", journal->j_devname);
779 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
780 jbd2_journal_abort(journal, err);
781 err = 0;
782 }
783
784 /*
785 * Get current oldest transaction in the log before we issue flush
786 * to the filesystem device. After the flush we can be sure that
787 * blocks of all older transactions are checkpointed to persistent
788 * storage and we will be safe to update journal start in the
789 * superblock with the numbers we get here.
790 */
791 update_tail =
792 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
793
794 write_lock(&journal->j_state_lock);
795 if (update_tail) {
796 long freed = first_block - journal->j_tail;
797
798 if (first_block < journal->j_tail)
799 freed += journal->j_last - journal->j_first;
800 /* Update tail only if we free significant amount of space */
801 if (freed < jbd2_journal_get_max_txn_bufs(journal))
802 update_tail = 0;
803 }
804 J_ASSERT(commit_transaction->t_state == T_COMMIT);
805 commit_transaction->t_state = T_COMMIT_DFLUSH;
806 write_unlock(&journal->j_state_lock);
807
808 /*
809 * If the journal is not located on the file system device,
810 * then we must flush the file system device before we issue
811 * the commit record
812 */
813 if (commit_transaction->t_need_data_flush &&
814 (journal->j_fs_dev != journal->j_dev) &&
815 (journal->j_flags & JBD2_BARRIER))
816 blkdev_issue_flush(journal->j_fs_dev);
817
818 /* Done it all: now write the commit record asynchronously. */
819 if (jbd2_has_feature_async_commit(journal)) {
820 err = journal_submit_commit_record(journal, commit_transaction,
821 &cbh, crc32_sum);
822 if (err)
823 jbd2_journal_abort(journal, err);
824 }
825
826 blk_finish_plug(&plug);
827
828 /* Lo and behold: we have just managed to send a transaction to
829 the log. Before we can commit it, wait for the IO so far to
830 complete. Control buffers being written are on the
831 transaction's t_log_list queue, and metadata buffers are on
832 the io_bufs list.
833
834 Wait for the buffers in reverse order. That way we are
835 less likely to be woken up until all IOs have completed, and
836 so we incur less scheduling load.
837 */
838
839 jbd2_debug(3, "JBD2: commit phase 3\n");
840
841 while (!list_empty(&io_bufs)) {
842 struct buffer_head *bh = list_entry(io_bufs.prev,
843 struct buffer_head,
844 b_assoc_buffers);
845
846 wait_on_buffer(bh);
847 cond_resched();
848
849 if (unlikely(!buffer_uptodate(bh)))
850 err = -EIO;
851 jbd2_unfile_log_bh(bh);
852 stats.run.rs_blocks_logged++;
853
854 /*
855 * The list contains temporary buffer heads created by
856 * jbd2_journal_write_metadata_buffer().
857 */
858 BUFFER_TRACE(bh, "dumping temporary bh");
859 __brelse(bh);
860 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
861 free_buffer_head(bh);
862
863 /* We also have to refile the corresponding shadowed buffer */
864 jh = commit_transaction->t_shadow_list->b_tprev;
865 bh = jh2bh(jh);
866 clear_buffer_jwrite(bh);
867 J_ASSERT_BH(bh, buffer_jbddirty(bh));
868 J_ASSERT_BH(bh, !buffer_shadow(bh));
869
870 /* The metadata is now released for reuse, but we need
871 to remember it against this transaction so that when
872 we finally commit, we can do any checkpointing
873 required. */
874 JBUFFER_TRACE(jh, "file as BJ_Forget");
875 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
876 JBUFFER_TRACE(jh, "brelse shadowed buffer");
877 __brelse(bh);
878 }
879
880 J_ASSERT (commit_transaction->t_shadow_list == NULL);
881
882 jbd2_debug(3, "JBD2: commit phase 4\n");
883
884 /* Here we wait for the revoke record and descriptor record buffers */
885 while (!list_empty(&log_bufs)) {
886 struct buffer_head *bh;
887
888 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
889 wait_on_buffer(bh);
890 cond_resched();
891
892 if (unlikely(!buffer_uptodate(bh)))
893 err = -EIO;
894
895 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
896 clear_buffer_jwrite(bh);
897 jbd2_unfile_log_bh(bh);
898 stats.run.rs_blocks_logged++;
899 __brelse(bh); /* One for getblk */
900 /* AKPM: bforget here */
901 }
902
903 if (err)
904 jbd2_journal_abort(journal, err);
905
906 jbd2_debug(3, "JBD2: commit phase 5\n");
907 write_lock(&journal->j_state_lock);
908 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
909 commit_transaction->t_state = T_COMMIT_JFLUSH;
910 write_unlock(&journal->j_state_lock);
911
912 if (!jbd2_has_feature_async_commit(journal)) {
913 err = journal_submit_commit_record(journal, commit_transaction,
914 &cbh, crc32_sum);
915 if (err)
916 jbd2_journal_abort(journal, err);
917 }
918 if (cbh)
919 err = journal_wait_on_commit_record(journal, cbh);
920 stats.run.rs_blocks_logged++;
921 if (jbd2_has_feature_async_commit(journal) &&
922 journal->j_flags & JBD2_BARRIER) {
923 blkdev_issue_flush(journal->j_dev);
924 }
925
926 if (err)
927 jbd2_journal_abort(journal, err);
928
929 WARN_ON_ONCE(
930 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
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 jbd2_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_shadow_list == NULL);
951
952restart_loop:
953 /*
954 * As there are other places (journal_unmap_buffer()) adding buffers
955 * to this list we have to be careful and hold the j_list_lock.
956 */
957 spin_lock(&journal->j_list_lock);
958 while (commit_transaction->t_forget) {
959 transaction_t *cp_transaction;
960 struct buffer_head *bh;
961 int try_to_free = 0;
962 bool drop_ref;
963
964 jh = commit_transaction->t_forget;
965 spin_unlock(&journal->j_list_lock);
966 bh = jh2bh(jh);
967 /*
968 * Get a reference so that bh cannot be freed before we are
969 * done with it.
970 */
971 get_bh(bh);
972 spin_lock(&jh->b_state_lock);
973 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
974
975 /*
976 * If there is undo-protected committed data against
977 * this buffer, then we can remove it now. If it is a
978 * buffer needing such protection, the old frozen_data
979 * field now points to a committed version of the
980 * buffer, so rotate that field to the new committed
981 * data.
982 *
983 * Otherwise, we can just throw away the frozen data now.
984 *
985 * We also know that the frozen data has already fired
986 * its triggers if they exist, so we can clear that too.
987 */
988 if (jh->b_committed_data) {
989 jbd2_free(jh->b_committed_data, bh->b_size);
990 jh->b_committed_data = NULL;
991 if (jh->b_frozen_data) {
992 jh->b_committed_data = jh->b_frozen_data;
993 jh->b_frozen_data = NULL;
994 jh->b_frozen_triggers = NULL;
995 }
996 } else if (jh->b_frozen_data) {
997 jbd2_free(jh->b_frozen_data, bh->b_size);
998 jh->b_frozen_data = NULL;
999 jh->b_frozen_triggers = NULL;
1000 }
1001
1002 spin_lock(&journal->j_list_lock);
1003 cp_transaction = jh->b_cp_transaction;
1004 if (cp_transaction) {
1005 JBUFFER_TRACE(jh, "remove from old cp transaction");
1006 cp_transaction->t_chp_stats.cs_dropped++;
1007 __jbd2_journal_remove_checkpoint(jh);
1008 }
1009
1010 /* Only re-checkpoint the buffer_head if it is marked
1011 * dirty. If the buffer was added to the BJ_Forget list
1012 * by jbd2_journal_forget, it may no longer be dirty and
1013 * there's no point in keeping a checkpoint record for
1014 * it. */
1015
1016 /*
1017 * A buffer which has been freed while still being journaled
1018 * by a previous transaction, refile the buffer to BJ_Forget of
1019 * the running transaction. If the just committed transaction
1020 * contains "add to orphan" operation, we can completely
1021 * invalidate the buffer now. We are rather through in that
1022 * since the buffer may be still accessible when blocksize <
1023 * pagesize and it is attached to the last partial page.
1024 */
1025 if (buffer_freed(bh) && !jh->b_next_transaction) {
1026 struct address_space *mapping;
1027
1028 clear_buffer_freed(bh);
1029 clear_buffer_jbddirty(bh);
1030
1031 /*
1032 * Block device buffers need to stay mapped all the
1033 * time, so it is enough to clear buffer_jbddirty and
1034 * buffer_freed bits. For the file mapping buffers (i.e.
1035 * journalled data) we need to unmap buffer and clear
1036 * more bits. We also need to be careful about the check
1037 * because the data page mapping can get cleared under
1038 * our hands. Note that if mapping == NULL, we don't
1039 * need to make buffer unmapped because the page is
1040 * already detached from the mapping and buffers cannot
1041 * get reused.
1042 */
1043 mapping = READ_ONCE(bh->b_page->mapping);
1044 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1045 clear_buffer_mapped(bh);
1046 clear_buffer_new(bh);
1047 clear_buffer_req(bh);
1048 bh->b_bdev = NULL;
1049 }
1050 }
1051
1052 if (buffer_jbddirty(bh)) {
1053 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1054 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1055 if (is_journal_aborted(journal))
1056 clear_buffer_jbddirty(bh);
1057 } else {
1058 J_ASSERT_BH(bh, !buffer_dirty(bh));
1059 /*
1060 * The buffer on BJ_Forget list and not jbddirty means
1061 * it has been freed by this transaction and hence it
1062 * could not have been reallocated until this
1063 * transaction has committed. *BUT* it could be
1064 * reallocated once we have written all the data to
1065 * disk and before we process the buffer on BJ_Forget
1066 * list.
1067 */
1068 if (!jh->b_next_transaction)
1069 try_to_free = 1;
1070 }
1071 JBUFFER_TRACE(jh, "refile or unfile buffer");
1072 drop_ref = __jbd2_journal_refile_buffer(jh);
1073 spin_unlock(&jh->b_state_lock);
1074 if (drop_ref)
1075 jbd2_journal_put_journal_head(jh);
1076 if (try_to_free)
1077 release_buffer_page(bh); /* Drops bh reference */
1078 else
1079 __brelse(bh);
1080 cond_resched_lock(&journal->j_list_lock);
1081 }
1082 spin_unlock(&journal->j_list_lock);
1083 /*
1084 * This is a bit sleazy. We use j_list_lock to protect transition
1085 * of a transaction into T_FINISHED state and calling
1086 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1087 * other checkpointing code processing the transaction...
1088 */
1089 write_lock(&journal->j_state_lock);
1090 spin_lock(&journal->j_list_lock);
1091 /*
1092 * Now recheck if some buffers did not get attached to the transaction
1093 * while the lock was dropped...
1094 */
1095 if (commit_transaction->t_forget) {
1096 spin_unlock(&journal->j_list_lock);
1097 write_unlock(&journal->j_state_lock);
1098 goto restart_loop;
1099 }
1100
1101 /* Add the transaction to the checkpoint list
1102 * __journal_remove_checkpoint() can not destroy transaction
1103 * under us because it is not marked as T_FINISHED yet */
1104 if (journal->j_checkpoint_transactions == NULL) {
1105 journal->j_checkpoint_transactions = commit_transaction;
1106 commit_transaction->t_cpnext = commit_transaction;
1107 commit_transaction->t_cpprev = commit_transaction;
1108 } else {
1109 commit_transaction->t_cpnext =
1110 journal->j_checkpoint_transactions;
1111 commit_transaction->t_cpprev =
1112 commit_transaction->t_cpnext->t_cpprev;
1113 commit_transaction->t_cpnext->t_cpprev =
1114 commit_transaction;
1115 commit_transaction->t_cpprev->t_cpnext =
1116 commit_transaction;
1117 }
1118 spin_unlock(&journal->j_list_lock);
1119
1120 /* Done with this transaction! */
1121
1122 jbd2_debug(3, "JBD2: commit phase 7\n");
1123
1124 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1125
1126 commit_transaction->t_start = jiffies;
1127 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1128 commit_transaction->t_start);
1129
1130 /*
1131 * File the transaction statistics
1132 */
1133 stats.ts_tid = commit_transaction->t_tid;
1134 stats.run.rs_handle_count =
1135 atomic_read(&commit_transaction->t_handle_count);
1136 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1137 commit_transaction->t_tid, &stats.run);
1138 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1139
1140 commit_transaction->t_state = T_COMMIT_CALLBACK;
1141 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1142 journal->j_commit_sequence = commit_transaction->t_tid;
1143 journal->j_committing_transaction = NULL;
1144 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1145
1146 /*
1147 * weight the commit time higher than the average time so we don't
1148 * react too strongly to vast changes in the commit time
1149 */
1150 if (likely(journal->j_average_commit_time))
1151 journal->j_average_commit_time = (commit_time +
1152 journal->j_average_commit_time*3) / 4;
1153 else
1154 journal->j_average_commit_time = commit_time;
1155
1156 write_unlock(&journal->j_state_lock);
1157
1158 if (journal->j_commit_callback)
1159 journal->j_commit_callback(journal, commit_transaction);
1160 if (journal->j_fc_cleanup_callback)
1161 journal->j_fc_cleanup_callback(journal, 1, commit_transaction->t_tid);
1162
1163 trace_jbd2_end_commit(journal, commit_transaction);
1164 jbd2_debug(1, "JBD2: commit %d complete, head %d\n",
1165 journal->j_commit_sequence, journal->j_tail_sequence);
1166
1167 write_lock(&journal->j_state_lock);
1168 journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1169 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1170 spin_lock(&journal->j_list_lock);
1171 commit_transaction->t_state = T_FINISHED;
1172 /* Check if the transaction can be dropped now that we are finished */
1173 if (commit_transaction->t_checkpoint_list == NULL &&
1174 commit_transaction->t_checkpoint_io_list == NULL) {
1175 __jbd2_journal_drop_transaction(journal, commit_transaction);
1176 jbd2_journal_free_transaction(commit_transaction);
1177 }
1178 spin_unlock(&journal->j_list_lock);
1179 write_unlock(&journal->j_state_lock);
1180 wake_up(&journal->j_wait_done_commit);
1181 wake_up(&journal->j_fc_wait);
1182
1183 /*
1184 * Calculate overall stats
1185 */
1186 spin_lock(&journal->j_history_lock);
1187 journal->j_stats.ts_tid++;
1188 journal->j_stats.ts_requested += stats.ts_requested;
1189 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1190 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1191 journal->j_stats.run.rs_running += stats.run.rs_running;
1192 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1193 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1194 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1195 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1196 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1197 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1198 spin_unlock(&journal->j_history_lock);
1199}
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 timespec now = current_kernel_time();
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(WRITE_SYNC | WRITE_FLUSH_FUA, bh);
159 else
160 ret = submit_bh(WRITE_SYNC, bh);
161
162 *cbh = bh;
163 return ret;
164}
165
166/*
167 * This function along with journal_submit_commit_record
168 * allows to write the commit record asynchronously.
169 */
170static int journal_wait_on_commit_record(journal_t *journal,
171 struct buffer_head *bh)
172{
173 int ret = 0;
174
175 clear_buffer_dirty(bh);
176 wait_on_buffer(bh);
177
178 if (unlikely(!buffer_uptodate(bh)))
179 ret = -EIO;
180 put_bh(bh); /* One for getblk() */
181
182 return ret;
183}
184
185/*
186 * write the filemap data using writepage() address_space_operations.
187 * We don't do block allocation here even for delalloc. We don't
188 * use writepages() because with dealyed allocation we may be doing
189 * block allocation in writepages().
190 */
191static int journal_submit_inode_data_buffers(struct address_space *mapping)
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 = 0,
198 .range_end = i_size_read(mapping->host),
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 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 jinode->i_flags |= JI_COMMIT_RUNNING;
260 spin_unlock(&journal->j_list_lock);
261 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
262 if (err) {
263 /*
264 * Because AS_EIO is cleared by
265 * filemap_fdatawait_range(), set it again so
266 * that user process can get -EIO from fsync().
267 */
268 set_bit(AS_EIO,
269 &jinode->i_vfs_inode->i_mapping->flags);
270
271 if (!ret)
272 ret = err;
273 }
274 spin_lock(&journal->j_list_lock);
275 jinode->i_flags &= ~JI_COMMIT_RUNNING;
276 smp_mb();
277 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
278 }
279
280 /* Now refile inode to proper lists */
281 list_for_each_entry_safe(jinode, next_i,
282 &commit_transaction->t_inode_list, i_list) {
283 list_del(&jinode->i_list);
284 if (jinode->i_next_transaction) {
285 jinode->i_transaction = jinode->i_next_transaction;
286 jinode->i_next_transaction = NULL;
287 list_add(&jinode->i_list,
288 &jinode->i_transaction->t_inode_list);
289 } else {
290 jinode->i_transaction = NULL;
291 }
292 }
293 spin_unlock(&journal->j_list_lock);
294
295 return ret;
296}
297
298static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
299{
300 struct page *page = bh->b_page;
301 char *addr;
302 __u32 checksum;
303
304 addr = kmap_atomic(page);
305 checksum = crc32_be(crc32_sum,
306 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
307 kunmap_atomic(addr);
308
309 return checksum;
310}
311
312static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
313 unsigned long long block)
314{
315 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
316 if (jbd2_has_feature_64bit(j))
317 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
318}
319
320static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
321 struct buffer_head *bh, __u32 sequence)
322{
323 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
324 struct page *page = bh->b_page;
325 __u8 *addr;
326 __u32 csum32;
327 __be32 seq;
328
329 if (!jbd2_journal_has_csum_v2or3(j))
330 return;
331
332 seq = cpu_to_be32(sequence);
333 addr = kmap_atomic(page);
334 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
335 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
336 bh->b_size);
337 kunmap_atomic(addr);
338
339 if (jbd2_has_feature_csum3(j))
340 tag3->t_checksum = cpu_to_be32(csum32);
341 else
342 tag->t_checksum = cpu_to_be16(csum32);
343}
344/*
345 * jbd2_journal_commit_transaction
346 *
347 * The primary function for committing a transaction to the log. This
348 * function is called by the journal thread to begin a complete commit.
349 */
350void jbd2_journal_commit_transaction(journal_t *journal)
351{
352 struct transaction_stats_s stats;
353 transaction_t *commit_transaction;
354 struct journal_head *jh;
355 struct buffer_head *descriptor;
356 struct buffer_head **wbuf = journal->j_wbuf;
357 int bufs;
358 int flags;
359 int err;
360 unsigned long long blocknr;
361 ktime_t start_time;
362 u64 commit_time;
363 char *tagp = NULL;
364 journal_block_tag_t *tag = NULL;
365 int space_left = 0;
366 int first_tag = 0;
367 int tag_flag;
368 int i;
369 int tag_bytes = journal_tag_bytes(journal);
370 struct buffer_head *cbh = NULL; /* For transactional checksums */
371 __u32 crc32_sum = ~0;
372 struct blk_plug plug;
373 /* Tail of the journal */
374 unsigned long first_block;
375 tid_t first_tid;
376 int update_tail;
377 int csum_size = 0;
378 LIST_HEAD(io_bufs);
379 LIST_HEAD(log_bufs);
380
381 if (jbd2_journal_has_csum_v2or3(journal))
382 csum_size = sizeof(struct jbd2_journal_block_tail);
383
384 /*
385 * First job: lock down the current transaction and wait for
386 * all outstanding updates to complete.
387 */
388
389 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
390 if (journal->j_flags & JBD2_FLUSHED) {
391 jbd_debug(3, "super block updated\n");
392 mutex_lock(&journal->j_checkpoint_mutex);
393 /*
394 * We hold j_checkpoint_mutex so tail cannot change under us.
395 * We don't need any special data guarantees for writing sb
396 * since journal is empty and it is ok for write to be
397 * flushed only with transaction commit.
398 */
399 jbd2_journal_update_sb_log_tail(journal,
400 journal->j_tail_sequence,
401 journal->j_tail,
402 WRITE_SYNC);
403 mutex_unlock(&journal->j_checkpoint_mutex);
404 } else {
405 jbd_debug(3, "superblock not updated\n");
406 }
407
408 J_ASSERT(journal->j_running_transaction != NULL);
409 J_ASSERT(journal->j_committing_transaction == NULL);
410
411 commit_transaction = journal->j_running_transaction;
412
413 trace_jbd2_start_commit(journal, commit_transaction);
414 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
415 commit_transaction->t_tid);
416
417 write_lock(&journal->j_state_lock);
418 J_ASSERT(commit_transaction->t_state == T_RUNNING);
419 commit_transaction->t_state = T_LOCKED;
420
421 trace_jbd2_commit_locking(journal, commit_transaction);
422 stats.run.rs_wait = commit_transaction->t_max_wait;
423 stats.run.rs_request_delay = 0;
424 stats.run.rs_locked = jiffies;
425 if (commit_transaction->t_requested)
426 stats.run.rs_request_delay =
427 jbd2_time_diff(commit_transaction->t_requested,
428 stats.run.rs_locked);
429 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
430 stats.run.rs_locked);
431
432 spin_lock(&commit_transaction->t_handle_lock);
433 while (atomic_read(&commit_transaction->t_updates)) {
434 DEFINE_WAIT(wait);
435
436 prepare_to_wait(&journal->j_wait_updates, &wait,
437 TASK_UNINTERRUPTIBLE);
438 if (atomic_read(&commit_transaction->t_updates)) {
439 spin_unlock(&commit_transaction->t_handle_lock);
440 write_unlock(&journal->j_state_lock);
441 schedule();
442 write_lock(&journal->j_state_lock);
443 spin_lock(&commit_transaction->t_handle_lock);
444 }
445 finish_wait(&journal->j_wait_updates, &wait);
446 }
447 spin_unlock(&commit_transaction->t_handle_lock);
448
449 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
450 journal->j_max_transaction_buffers);
451
452 /*
453 * First thing we are allowed to do is to discard any remaining
454 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
455 * that there are no such buffers: if a large filesystem
456 * operation like a truncate needs to split itself over multiple
457 * transactions, then it may try to do a jbd2_journal_restart() while
458 * there are still BJ_Reserved buffers outstanding. These must
459 * be released cleanly from the current transaction.
460 *
461 * In this case, the filesystem must still reserve write access
462 * again before modifying the buffer in the new transaction, but
463 * we do not require it to remember exactly which old buffers it
464 * has reserved. This is consistent with the existing behaviour
465 * that multiple jbd2_journal_get_write_access() calls to the same
466 * buffer are perfectly permissible.
467 */
468 while (commit_transaction->t_reserved_list) {
469 jh = commit_transaction->t_reserved_list;
470 JBUFFER_TRACE(jh, "reserved, unused: refile");
471 /*
472 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
473 * leave undo-committed data.
474 */
475 if (jh->b_committed_data) {
476 struct buffer_head *bh = jh2bh(jh);
477
478 jbd_lock_bh_state(bh);
479 jbd2_free(jh->b_committed_data, bh->b_size);
480 jh->b_committed_data = NULL;
481 jbd_unlock_bh_state(bh);
482 }
483 jbd2_journal_refile_buffer(journal, jh);
484 }
485
486 /*
487 * Now try to drop any written-back buffers from the journal's
488 * checkpoint lists. We do this *before* commit because it potentially
489 * frees some memory
490 */
491 spin_lock(&journal->j_list_lock);
492 __jbd2_journal_clean_checkpoint_list(journal, false);
493 spin_unlock(&journal->j_list_lock);
494
495 jbd_debug(3, "JBD2: commit phase 1\n");
496
497 /*
498 * Clear revoked flag to reflect there is no revoked buffers
499 * in the next transaction which is going to be started.
500 */
501 jbd2_clear_buffer_revoked_flags(journal);
502
503 /*
504 * Switch to a new revoke table.
505 */
506 jbd2_journal_switch_revoke_table(journal);
507
508 /*
509 * Reserved credits cannot be claimed anymore, free them
510 */
511 atomic_sub(atomic_read(&journal->j_reserved_credits),
512 &commit_transaction->t_outstanding_credits);
513
514 trace_jbd2_commit_flushing(journal, commit_transaction);
515 stats.run.rs_flushing = jiffies;
516 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
517 stats.run.rs_flushing);
518
519 commit_transaction->t_state = T_FLUSH;
520 journal->j_committing_transaction = commit_transaction;
521 journal->j_running_transaction = NULL;
522 start_time = ktime_get();
523 commit_transaction->t_log_start = journal->j_head;
524 wake_up(&journal->j_wait_transaction_locked);
525 write_unlock(&journal->j_state_lock);
526
527 jbd_debug(3, "JBD2: commit phase 2a\n");
528
529 /*
530 * Now start flushing things to disk, in the order they appear
531 * on the transaction lists. Data blocks go first.
532 */
533 err = journal_submit_data_buffers(journal, commit_transaction);
534 if (err)
535 jbd2_journal_abort(journal, err);
536
537 blk_start_plug(&plug);
538 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
539
540 jbd_debug(3, "JBD2: commit phase 2b\n");
541
542 /*
543 * Way to go: we have now written out all of the data for a
544 * transaction! Now comes the tricky part: we need to write out
545 * metadata. Loop over the transaction's entire buffer list:
546 */
547 write_lock(&journal->j_state_lock);
548 commit_transaction->t_state = T_COMMIT;
549 write_unlock(&journal->j_state_lock);
550
551 trace_jbd2_commit_logging(journal, commit_transaction);
552 stats.run.rs_logging = jiffies;
553 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
554 stats.run.rs_logging);
555 stats.run.rs_blocks =
556 atomic_read(&commit_transaction->t_outstanding_credits);
557 stats.run.rs_blocks_logged = 0;
558
559 J_ASSERT(commit_transaction->t_nr_buffers <=
560 atomic_read(&commit_transaction->t_outstanding_credits));
561
562 err = 0;
563 bufs = 0;
564 descriptor = NULL;
565 while (commit_transaction->t_buffers) {
566
567 /* Find the next buffer to be journaled... */
568
569 jh = commit_transaction->t_buffers;
570
571 /* If we're in abort mode, we just un-journal the buffer and
572 release it. */
573
574 if (is_journal_aborted(journal)) {
575 clear_buffer_jbddirty(jh2bh(jh));
576 JBUFFER_TRACE(jh, "journal is aborting: refile");
577 jbd2_buffer_abort_trigger(jh,
578 jh->b_frozen_data ?
579 jh->b_frozen_triggers :
580 jh->b_triggers);
581 jbd2_journal_refile_buffer(journal, jh);
582 /* If that was the last one, we need to clean up
583 * any descriptor buffers which may have been
584 * already allocated, even if we are now
585 * aborting. */
586 if (!commit_transaction->t_buffers)
587 goto start_journal_io;
588 continue;
589 }
590
591 /* Make sure we have a descriptor block in which to
592 record the metadata buffer. */
593
594 if (!descriptor) {
595 J_ASSERT (bufs == 0);
596
597 jbd_debug(4, "JBD2: get descriptor\n");
598
599 descriptor = jbd2_journal_get_descriptor_buffer(
600 commit_transaction,
601 JBD2_DESCRIPTOR_BLOCK);
602 if (!descriptor) {
603 jbd2_journal_abort(journal, -EIO);
604 continue;
605 }
606
607 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
608 (unsigned long long)descriptor->b_blocknr,
609 descriptor->b_data);
610 tagp = &descriptor->b_data[sizeof(journal_header_t)];
611 space_left = descriptor->b_size -
612 sizeof(journal_header_t);
613 first_tag = 1;
614 set_buffer_jwrite(descriptor);
615 set_buffer_dirty(descriptor);
616 wbuf[bufs++] = descriptor;
617
618 /* Record it so that we can wait for IO
619 completion later */
620 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
621 jbd2_file_log_bh(&log_bufs, descriptor);
622 }
623
624 /* Where is the buffer to be written? */
625
626 err = jbd2_journal_next_log_block(journal, &blocknr);
627 /* If the block mapping failed, just abandon the buffer
628 and repeat this loop: we'll fall into the
629 refile-on-abort condition above. */
630 if (err) {
631 jbd2_journal_abort(journal, err);
632 continue;
633 }
634
635 /*
636 * start_this_handle() uses t_outstanding_credits to determine
637 * the free space in the log, but this counter is changed
638 * by jbd2_journal_next_log_block() also.
639 */
640 atomic_dec(&commit_transaction->t_outstanding_credits);
641
642 /* Bump b_count to prevent truncate from stumbling over
643 the shadowed buffer! @@@ This can go if we ever get
644 rid of the shadow pairing of buffers. */
645 atomic_inc(&jh2bh(jh)->b_count);
646
647 /*
648 * Make a temporary IO buffer with which to write it out
649 * (this will requeue the metadata buffer to BJ_Shadow).
650 */
651 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
652 JBUFFER_TRACE(jh, "ph3: write metadata");
653 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
654 jh, &wbuf[bufs], blocknr);
655 if (flags < 0) {
656 jbd2_journal_abort(journal, flags);
657 continue;
658 }
659 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
660
661 /* Record the new block's tag in the current descriptor
662 buffer */
663
664 tag_flag = 0;
665 if (flags & 1)
666 tag_flag |= JBD2_FLAG_ESCAPE;
667 if (!first_tag)
668 tag_flag |= JBD2_FLAG_SAME_UUID;
669
670 tag = (journal_block_tag_t *) tagp;
671 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
672 tag->t_flags = cpu_to_be16(tag_flag);
673 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
674 commit_transaction->t_tid);
675 tagp += tag_bytes;
676 space_left -= tag_bytes;
677 bufs++;
678
679 if (first_tag) {
680 memcpy (tagp, journal->j_uuid, 16);
681 tagp += 16;
682 space_left -= 16;
683 first_tag = 0;
684 }
685
686 /* If there's no more to do, or if the descriptor is full,
687 let the IO rip! */
688
689 if (bufs == journal->j_wbufsize ||
690 commit_transaction->t_buffers == NULL ||
691 space_left < tag_bytes + 16 + csum_size) {
692
693 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
694
695 /* Write an end-of-descriptor marker before
696 submitting the IOs. "tag" still points to
697 the last tag we set up. */
698
699 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
700
701 jbd2_descriptor_block_csum_set(journal, descriptor);
702start_journal_io:
703 for (i = 0; i < bufs; i++) {
704 struct buffer_head *bh = wbuf[i];
705 /*
706 * Compute checksum.
707 */
708 if (jbd2_has_feature_checksum(journal)) {
709 crc32_sum =
710 jbd2_checksum_data(crc32_sum, bh);
711 }
712
713 lock_buffer(bh);
714 clear_buffer_dirty(bh);
715 set_buffer_uptodate(bh);
716 bh->b_end_io = journal_end_buffer_io_sync;
717 submit_bh(WRITE_SYNC, bh);
718 }
719 cond_resched();
720 stats.run.rs_blocks_logged += bufs;
721
722 /* Force a new descriptor to be generated next
723 time round the loop. */
724 descriptor = NULL;
725 bufs = 0;
726 }
727 }
728
729 err = journal_finish_inode_data_buffers(journal, commit_transaction);
730 if (err) {
731 printk(KERN_WARNING
732 "JBD2: Detected IO errors while flushing file data "
733 "on %s\n", journal->j_devname);
734 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
735 jbd2_journal_abort(journal, err);
736 err = 0;
737 }
738
739 /*
740 * Get current oldest transaction in the log before we issue flush
741 * to the filesystem device. After the flush we can be sure that
742 * blocks of all older transactions are checkpointed to persistent
743 * storage and we will be safe to update journal start in the
744 * superblock with the numbers we get here.
745 */
746 update_tail =
747 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
748
749 write_lock(&journal->j_state_lock);
750 if (update_tail) {
751 long freed = first_block - journal->j_tail;
752
753 if (first_block < journal->j_tail)
754 freed += journal->j_last - journal->j_first;
755 /* Update tail only if we free significant amount of space */
756 if (freed < journal->j_maxlen / 4)
757 update_tail = 0;
758 }
759 J_ASSERT(commit_transaction->t_state == T_COMMIT);
760 commit_transaction->t_state = T_COMMIT_DFLUSH;
761 write_unlock(&journal->j_state_lock);
762
763 /*
764 * If the journal is not located on the file system device,
765 * then we must flush the file system device before we issue
766 * the commit record
767 */
768 if (commit_transaction->t_need_data_flush &&
769 (journal->j_fs_dev != journal->j_dev) &&
770 (journal->j_flags & JBD2_BARRIER))
771 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
772
773 /* Done it all: now write the commit record asynchronously. */
774 if (jbd2_has_feature_async_commit(journal)) {
775 err = journal_submit_commit_record(journal, commit_transaction,
776 &cbh, crc32_sum);
777 if (err)
778 __jbd2_journal_abort_hard(journal);
779 }
780
781 blk_finish_plug(&plug);
782
783 /* Lo and behold: we have just managed to send a transaction to
784 the log. Before we can commit it, wait for the IO so far to
785 complete. Control buffers being written are on the
786 transaction's t_log_list queue, and metadata buffers are on
787 the io_bufs list.
788
789 Wait for the buffers in reverse order. That way we are
790 less likely to be woken up until all IOs have completed, and
791 so we incur less scheduling load.
792 */
793
794 jbd_debug(3, "JBD2: commit phase 3\n");
795
796 while (!list_empty(&io_bufs)) {
797 struct buffer_head *bh = list_entry(io_bufs.prev,
798 struct buffer_head,
799 b_assoc_buffers);
800
801 wait_on_buffer(bh);
802 cond_resched();
803
804 if (unlikely(!buffer_uptodate(bh)))
805 err = -EIO;
806 jbd2_unfile_log_bh(bh);
807
808 /*
809 * The list contains temporary buffer heads created by
810 * jbd2_journal_write_metadata_buffer().
811 */
812 BUFFER_TRACE(bh, "dumping temporary bh");
813 __brelse(bh);
814 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
815 free_buffer_head(bh);
816
817 /* We also have to refile the corresponding shadowed buffer */
818 jh = commit_transaction->t_shadow_list->b_tprev;
819 bh = jh2bh(jh);
820 clear_buffer_jwrite(bh);
821 J_ASSERT_BH(bh, buffer_jbddirty(bh));
822 J_ASSERT_BH(bh, !buffer_shadow(bh));
823
824 /* The metadata is now released for reuse, but we need
825 to remember it against this transaction so that when
826 we finally commit, we can do any checkpointing
827 required. */
828 JBUFFER_TRACE(jh, "file as BJ_Forget");
829 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
830 JBUFFER_TRACE(jh, "brelse shadowed buffer");
831 __brelse(bh);
832 }
833
834 J_ASSERT (commit_transaction->t_shadow_list == NULL);
835
836 jbd_debug(3, "JBD2: commit phase 4\n");
837
838 /* Here we wait for the revoke record and descriptor record buffers */
839 while (!list_empty(&log_bufs)) {
840 struct buffer_head *bh;
841
842 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
843 wait_on_buffer(bh);
844 cond_resched();
845
846 if (unlikely(!buffer_uptodate(bh)))
847 err = -EIO;
848
849 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
850 clear_buffer_jwrite(bh);
851 jbd2_unfile_log_bh(bh);
852 __brelse(bh); /* One for getblk */
853 /* AKPM: bforget here */
854 }
855
856 if (err)
857 jbd2_journal_abort(journal, err);
858
859 jbd_debug(3, "JBD2: commit phase 5\n");
860 write_lock(&journal->j_state_lock);
861 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
862 commit_transaction->t_state = T_COMMIT_JFLUSH;
863 write_unlock(&journal->j_state_lock);
864
865 if (!jbd2_has_feature_async_commit(journal)) {
866 err = journal_submit_commit_record(journal, commit_transaction,
867 &cbh, crc32_sum);
868 if (err)
869 __jbd2_journal_abort_hard(journal);
870 }
871 if (cbh)
872 err = journal_wait_on_commit_record(journal, cbh);
873 if (jbd2_has_feature_async_commit(journal) &&
874 journal->j_flags & JBD2_BARRIER) {
875 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
876 }
877
878 if (err)
879 jbd2_journal_abort(journal, err);
880
881 /*
882 * Now disk caches for filesystem device are flushed so we are safe to
883 * erase checkpointed transactions from the log by updating journal
884 * superblock.
885 */
886 if (update_tail)
887 jbd2_update_log_tail(journal, first_tid, first_block);
888
889 /* End of a transaction! Finally, we can do checkpoint
890 processing: any buffers committed as a result of this
891 transaction can be removed from any checkpoint list it was on
892 before. */
893
894 jbd_debug(3, "JBD2: commit phase 6\n");
895
896 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
897 J_ASSERT(commit_transaction->t_buffers == NULL);
898 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
899 J_ASSERT(commit_transaction->t_shadow_list == NULL);
900
901restart_loop:
902 /*
903 * As there are other places (journal_unmap_buffer()) adding buffers
904 * to this list we have to be careful and hold the j_list_lock.
905 */
906 spin_lock(&journal->j_list_lock);
907 while (commit_transaction->t_forget) {
908 transaction_t *cp_transaction;
909 struct buffer_head *bh;
910 int try_to_free = 0;
911
912 jh = commit_transaction->t_forget;
913 spin_unlock(&journal->j_list_lock);
914 bh = jh2bh(jh);
915 /*
916 * Get a reference so that bh cannot be freed before we are
917 * done with it.
918 */
919 get_bh(bh);
920 jbd_lock_bh_state(bh);
921 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
922
923 /*
924 * If there is undo-protected committed data against
925 * this buffer, then we can remove it now. If it is a
926 * buffer needing such protection, the old frozen_data
927 * field now points to a committed version of the
928 * buffer, so rotate that field to the new committed
929 * data.
930 *
931 * Otherwise, we can just throw away the frozen data now.
932 *
933 * We also know that the frozen data has already fired
934 * its triggers if they exist, so we can clear that too.
935 */
936 if (jh->b_committed_data) {
937 jbd2_free(jh->b_committed_data, bh->b_size);
938 jh->b_committed_data = NULL;
939 if (jh->b_frozen_data) {
940 jh->b_committed_data = jh->b_frozen_data;
941 jh->b_frozen_data = NULL;
942 jh->b_frozen_triggers = NULL;
943 }
944 } else if (jh->b_frozen_data) {
945 jbd2_free(jh->b_frozen_data, bh->b_size);
946 jh->b_frozen_data = NULL;
947 jh->b_frozen_triggers = NULL;
948 }
949
950 spin_lock(&journal->j_list_lock);
951 cp_transaction = jh->b_cp_transaction;
952 if (cp_transaction) {
953 JBUFFER_TRACE(jh, "remove from old cp transaction");
954 cp_transaction->t_chp_stats.cs_dropped++;
955 __jbd2_journal_remove_checkpoint(jh);
956 }
957
958 /* Only re-checkpoint the buffer_head if it is marked
959 * dirty. If the buffer was added to the BJ_Forget list
960 * by jbd2_journal_forget, it may no longer be dirty and
961 * there's no point in keeping a checkpoint record for
962 * it. */
963
964 /*
965 * A buffer which has been freed while still being journaled by
966 * a previous transaction.
967 */
968 if (buffer_freed(bh)) {
969 /*
970 * If the running transaction is the one containing
971 * "add to orphan" operation (b_next_transaction !=
972 * NULL), we have to wait for that transaction to
973 * commit before we can really get rid of the buffer.
974 * So just clear b_modified to not confuse transaction
975 * credit accounting and refile the buffer to
976 * BJ_Forget of the running transaction. If the just
977 * committed transaction contains "add to orphan"
978 * operation, we can completely invalidate the buffer
979 * now. We are rather through in that since the
980 * buffer may be still accessible when blocksize <
981 * pagesize and it is attached to the last partial
982 * page.
983 */
984 jh->b_modified = 0;
985 if (!jh->b_next_transaction) {
986 clear_buffer_freed(bh);
987 clear_buffer_jbddirty(bh);
988 clear_buffer_mapped(bh);
989 clear_buffer_new(bh);
990 clear_buffer_req(bh);
991 bh->b_bdev = NULL;
992 }
993 }
994
995 if (buffer_jbddirty(bh)) {
996 JBUFFER_TRACE(jh, "add to new checkpointing trans");
997 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
998 if (is_journal_aborted(journal))
999 clear_buffer_jbddirty(bh);
1000 } else {
1001 J_ASSERT_BH(bh, !buffer_dirty(bh));
1002 /*
1003 * The buffer on BJ_Forget list and not jbddirty means
1004 * it has been freed by this transaction and hence it
1005 * could not have been reallocated until this
1006 * transaction has committed. *BUT* it could be
1007 * reallocated once we have written all the data to
1008 * disk and before we process the buffer on BJ_Forget
1009 * list.
1010 */
1011 if (!jh->b_next_transaction)
1012 try_to_free = 1;
1013 }
1014 JBUFFER_TRACE(jh, "refile or unfile buffer");
1015 __jbd2_journal_refile_buffer(jh);
1016 jbd_unlock_bh_state(bh);
1017 if (try_to_free)
1018 release_buffer_page(bh); /* Drops bh reference */
1019 else
1020 __brelse(bh);
1021 cond_resched_lock(&journal->j_list_lock);
1022 }
1023 spin_unlock(&journal->j_list_lock);
1024 /*
1025 * This is a bit sleazy. We use j_list_lock to protect transition
1026 * of a transaction into T_FINISHED state and calling
1027 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1028 * other checkpointing code processing the transaction...
1029 */
1030 write_lock(&journal->j_state_lock);
1031 spin_lock(&journal->j_list_lock);
1032 /*
1033 * Now recheck if some buffers did not get attached to the transaction
1034 * while the lock was dropped...
1035 */
1036 if (commit_transaction->t_forget) {
1037 spin_unlock(&journal->j_list_lock);
1038 write_unlock(&journal->j_state_lock);
1039 goto restart_loop;
1040 }
1041
1042 /* Add the transaction to the checkpoint list
1043 * __journal_remove_checkpoint() can not destroy transaction
1044 * under us because it is not marked as T_FINISHED yet */
1045 if (journal->j_checkpoint_transactions == NULL) {
1046 journal->j_checkpoint_transactions = commit_transaction;
1047 commit_transaction->t_cpnext = commit_transaction;
1048 commit_transaction->t_cpprev = commit_transaction;
1049 } else {
1050 commit_transaction->t_cpnext =
1051 journal->j_checkpoint_transactions;
1052 commit_transaction->t_cpprev =
1053 commit_transaction->t_cpnext->t_cpprev;
1054 commit_transaction->t_cpnext->t_cpprev =
1055 commit_transaction;
1056 commit_transaction->t_cpprev->t_cpnext =
1057 commit_transaction;
1058 }
1059 spin_unlock(&journal->j_list_lock);
1060
1061 /* Done with this transaction! */
1062
1063 jbd_debug(3, "JBD2: commit phase 7\n");
1064
1065 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1066
1067 commit_transaction->t_start = jiffies;
1068 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1069 commit_transaction->t_start);
1070
1071 /*
1072 * File the transaction statistics
1073 */
1074 stats.ts_tid = commit_transaction->t_tid;
1075 stats.run.rs_handle_count =
1076 atomic_read(&commit_transaction->t_handle_count);
1077 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1078 commit_transaction->t_tid, &stats.run);
1079 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1080
1081 commit_transaction->t_state = T_COMMIT_CALLBACK;
1082 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1083 journal->j_commit_sequence = commit_transaction->t_tid;
1084 journal->j_committing_transaction = NULL;
1085 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1086
1087 /*
1088 * weight the commit time higher than the average time so we don't
1089 * react too strongly to vast changes in the commit time
1090 */
1091 if (likely(journal->j_average_commit_time))
1092 journal->j_average_commit_time = (commit_time +
1093 journal->j_average_commit_time*3) / 4;
1094 else
1095 journal->j_average_commit_time = commit_time;
1096
1097 write_unlock(&journal->j_state_lock);
1098
1099 if (journal->j_commit_callback)
1100 journal->j_commit_callback(journal, commit_transaction);
1101
1102 trace_jbd2_end_commit(journal, commit_transaction);
1103 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1104 journal->j_commit_sequence, journal->j_tail_sequence);
1105
1106 write_lock(&journal->j_state_lock);
1107 spin_lock(&journal->j_list_lock);
1108 commit_transaction->t_state = T_FINISHED;
1109 /* Check if the transaction can be dropped now that we are finished */
1110 if (commit_transaction->t_checkpoint_list == NULL &&
1111 commit_transaction->t_checkpoint_io_list == NULL) {
1112 __jbd2_journal_drop_transaction(journal, commit_transaction);
1113 jbd2_journal_free_transaction(commit_transaction);
1114 }
1115 spin_unlock(&journal->j_list_lock);
1116 write_unlock(&journal->j_state_lock);
1117 wake_up(&journal->j_wait_done_commit);
1118
1119 /*
1120 * Calculate overall stats
1121 */
1122 spin_lock(&journal->j_history_lock);
1123 journal->j_stats.ts_tid++;
1124 journal->j_stats.ts_requested += stats.ts_requested;
1125 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1126 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1127 journal->j_stats.run.rs_running += stats.run.rs_running;
1128 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1129 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1130 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1131 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1132 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1133 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1134 spin_unlock(&journal->j_history_lock);
1135}