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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * linux/fs/jbd2/commit.c
4 *
5 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
6 *
7 * Copyright 1998 Red Hat corp --- All Rights Reserved
8 *
9 * Journal commit routines for the generic filesystem journaling code;
10 * part of the ext2fs journaling system.
11 */
12
13#include <linux/time.h>
14#include <linux/fs.h>
15#include <linux/jbd2.h>
16#include <linux/errno.h>
17#include <linux/slab.h>
18#include <linux/mm.h>
19#include <linux/pagemap.h>
20#include <linux/jiffies.h>
21#include <linux/crc32.h>
22#include <linux/writeback.h>
23#include <linux/backing-dev.h>
24#include <linux/bio.h>
25#include <linux/blkdev.h>
26#include <linux/bitops.h>
27#include <trace/events/jbd2.h>
28
29/*
30 * IO end handler for temporary buffer_heads handling writes to the journal.
31 */
32static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
33{
34 struct buffer_head *orig_bh = bh->b_private;
35
36 BUFFER_TRACE(bh, "");
37 if (uptodate)
38 set_buffer_uptodate(bh);
39 else
40 clear_buffer_uptodate(bh);
41 if (orig_bh) {
42 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
43 smp_mb__after_atomic();
44 wake_up_bit(&orig_bh->b_state, BH_Shadow);
45 }
46 unlock_buffer(bh);
47}
48
49/*
50 * When an ext4 file is truncated, it is possible that some pages are not
51 * successfully freed, because they are attached to a committing transaction.
52 * After the transaction commits, these pages are left on the LRU, with no
53 * ->mapping, and with attached buffers. These pages are trivially reclaimable
54 * by the VM, but their apparent absence upsets the VM accounting, and it makes
55 * the numbers in /proc/meminfo look odd.
56 *
57 * So here, we have a buffer which has just come off the forget list. Look to
58 * see if we can strip all buffers from the backing page.
59 *
60 * Called under lock_journal(), and possibly under journal_datalist_lock. The
61 * caller provided us with a ref against the buffer, and we drop that here.
62 */
63static void release_buffer_page(struct buffer_head *bh)
64{
65 struct page *page;
66
67 if (buffer_dirty(bh))
68 goto nope;
69 if (atomic_read(&bh->b_count) != 1)
70 goto nope;
71 page = bh->b_page;
72 if (!page)
73 goto nope;
74 if (page->mapping)
75 goto nope;
76
77 /* OK, it's a truncated page */
78 if (!trylock_page(page))
79 goto nope;
80
81 get_page(page);
82 __brelse(bh);
83 try_to_free_buffers(page);
84 unlock_page(page);
85 put_page(page);
86 return;
87
88nope:
89 __brelse(bh);
90}
91
92static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
93{
94 struct commit_header *h;
95 __u32 csum;
96
97 if (!jbd2_journal_has_csum_v2or3(j))
98 return;
99
100 h = (struct commit_header *)(bh->b_data);
101 h->h_chksum_type = 0;
102 h->h_chksum_size = 0;
103 h->h_chksum[0] = 0;
104 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
105 h->h_chksum[0] = cpu_to_be32(csum);
106}
107
108/*
109 * Done it all: now submit the commit record. We should have
110 * cleaned up our previous buffers by now, so if we are in abort
111 * mode we can now just skip the rest of the journal write
112 * entirely.
113 *
114 * Returns 1 if the journal needs to be aborted or 0 on success
115 */
116static int journal_submit_commit_record(journal_t *journal,
117 transaction_t *commit_transaction,
118 struct buffer_head **cbh,
119 __u32 crc32_sum)
120{
121 struct commit_header *tmp;
122 struct buffer_head *bh;
123 int ret;
124 struct timespec64 now = current_kernel_time64();
125
126 *cbh = NULL;
127
128 if (is_journal_aborted(journal))
129 return 0;
130
131 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
132 JBD2_COMMIT_BLOCK);
133 if (!bh)
134 return 1;
135
136 tmp = (struct commit_header *)bh->b_data;
137 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
138 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
139
140 if (jbd2_has_feature_checksum(journal)) {
141 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
142 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
143 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
144 }
145 jbd2_commit_block_csum_set(journal, bh);
146
147 BUFFER_TRACE(bh, "submit commit block");
148 lock_buffer(bh);
149 clear_buffer_dirty(bh);
150 set_buffer_uptodate(bh);
151 bh->b_end_io = journal_end_buffer_io_sync;
152
153 if (journal->j_flags & JBD2_BARRIER &&
154 !jbd2_has_feature_async_commit(journal))
155 ret = submit_bh(REQ_OP_WRITE,
156 REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh);
157 else
158 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
159
160 *cbh = bh;
161 return ret;
162}
163
164/*
165 * This function along with journal_submit_commit_record
166 * allows to write the commit record asynchronously.
167 */
168static int journal_wait_on_commit_record(journal_t *journal,
169 struct buffer_head *bh)
170{
171 int ret = 0;
172
173 clear_buffer_dirty(bh);
174 wait_on_buffer(bh);
175
176 if (unlikely(!buffer_uptodate(bh)))
177 ret = -EIO;
178 put_bh(bh); /* One for getblk() */
179
180 return ret;
181}
182
183/*
184 * write the filemap data using writepage() address_space_operations.
185 * We don't do block allocation here even for delalloc. We don't
186 * use writepages() because with dealyed allocation we may be doing
187 * block allocation in writepages().
188 */
189static int journal_submit_inode_data_buffers(struct address_space *mapping)
190{
191 int ret;
192 struct writeback_control wbc = {
193 .sync_mode = WB_SYNC_ALL,
194 .nr_to_write = mapping->nrpages * 2,
195 .range_start = 0,
196 .range_end = i_size_read(mapping->host),
197 };
198
199 ret = generic_writepages(mapping, &wbc);
200 return ret;
201}
202
203/*
204 * Submit all the data buffers of inode associated with the transaction to
205 * disk.
206 *
207 * We are in a committing transaction. Therefore no new inode can be added to
208 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
209 * operate on from being released while we write out pages.
210 */
211static int journal_submit_data_buffers(journal_t *journal,
212 transaction_t *commit_transaction)
213{
214 struct jbd2_inode *jinode;
215 int err, ret = 0;
216 struct address_space *mapping;
217
218 spin_lock(&journal->j_list_lock);
219 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
220 if (!(jinode->i_flags & JI_WRITE_DATA))
221 continue;
222 mapping = jinode->i_vfs_inode->i_mapping;
223 jinode->i_flags |= JI_COMMIT_RUNNING;
224 spin_unlock(&journal->j_list_lock);
225 /*
226 * submit the inode data buffers. We use writepage
227 * instead of writepages. Because writepages can do
228 * block allocation with delalloc. We need to write
229 * only allocated blocks here.
230 */
231 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
232 err = journal_submit_inode_data_buffers(mapping);
233 if (!ret)
234 ret = err;
235 spin_lock(&journal->j_list_lock);
236 J_ASSERT(jinode->i_transaction == commit_transaction);
237 jinode->i_flags &= ~JI_COMMIT_RUNNING;
238 smp_mb();
239 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
240 }
241 spin_unlock(&journal->j_list_lock);
242 return ret;
243}
244
245/*
246 * Wait for data submitted for writeout, refile inodes to proper
247 * transaction if needed.
248 *
249 */
250static int journal_finish_inode_data_buffers(journal_t *journal,
251 transaction_t *commit_transaction)
252{
253 struct jbd2_inode *jinode, *next_i;
254 int err, ret = 0;
255
256 /* For locking, see the comment in journal_submit_data_buffers() */
257 spin_lock(&journal->j_list_lock);
258 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
259 if (!(jinode->i_flags & JI_WAIT_DATA))
260 continue;
261 jinode->i_flags |= JI_COMMIT_RUNNING;
262 spin_unlock(&journal->j_list_lock);
263 err = filemap_fdatawait_keep_errors(
264 jinode->i_vfs_inode->i_mapping);
265 if (!ret)
266 ret = err;
267 spin_lock(&journal->j_list_lock);
268 jinode->i_flags &= ~JI_COMMIT_RUNNING;
269 smp_mb();
270 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
271 }
272
273 /* Now refile inode to proper lists */
274 list_for_each_entry_safe(jinode, next_i,
275 &commit_transaction->t_inode_list, i_list) {
276 list_del(&jinode->i_list);
277 if (jinode->i_next_transaction) {
278 jinode->i_transaction = jinode->i_next_transaction;
279 jinode->i_next_transaction = NULL;
280 list_add(&jinode->i_list,
281 &jinode->i_transaction->t_inode_list);
282 } else {
283 jinode->i_transaction = NULL;
284 }
285 }
286 spin_unlock(&journal->j_list_lock);
287
288 return ret;
289}
290
291static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
292{
293 struct page *page = bh->b_page;
294 char *addr;
295 __u32 checksum;
296
297 addr = kmap_atomic(page);
298 checksum = crc32_be(crc32_sum,
299 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
300 kunmap_atomic(addr);
301
302 return checksum;
303}
304
305static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
306 unsigned long long block)
307{
308 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
309 if (jbd2_has_feature_64bit(j))
310 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
311}
312
313static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
314 struct buffer_head *bh, __u32 sequence)
315{
316 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
317 struct page *page = bh->b_page;
318 __u8 *addr;
319 __u32 csum32;
320 __be32 seq;
321
322 if (!jbd2_journal_has_csum_v2or3(j))
323 return;
324
325 seq = cpu_to_be32(sequence);
326 addr = kmap_atomic(page);
327 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
328 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
329 bh->b_size);
330 kunmap_atomic(addr);
331
332 if (jbd2_has_feature_csum3(j))
333 tag3->t_checksum = cpu_to_be32(csum32);
334 else
335 tag->t_checksum = cpu_to_be16(csum32);
336}
337/*
338 * jbd2_journal_commit_transaction
339 *
340 * The primary function for committing a transaction to the log. This
341 * function is called by the journal thread to begin a complete commit.
342 */
343void jbd2_journal_commit_transaction(journal_t *journal)
344{
345 struct transaction_stats_s stats;
346 transaction_t *commit_transaction;
347 struct journal_head *jh;
348 struct buffer_head *descriptor;
349 struct buffer_head **wbuf = journal->j_wbuf;
350 int bufs;
351 int flags;
352 int err;
353 unsigned long long blocknr;
354 ktime_t start_time;
355 u64 commit_time;
356 char *tagp = NULL;
357 journal_block_tag_t *tag = NULL;
358 int space_left = 0;
359 int first_tag = 0;
360 int tag_flag;
361 int i;
362 int tag_bytes = journal_tag_bytes(journal);
363 struct buffer_head *cbh = NULL; /* For transactional checksums */
364 __u32 crc32_sum = ~0;
365 struct blk_plug plug;
366 /* Tail of the journal */
367 unsigned long first_block;
368 tid_t first_tid;
369 int update_tail;
370 int csum_size = 0;
371 LIST_HEAD(io_bufs);
372 LIST_HEAD(log_bufs);
373
374 if (jbd2_journal_has_csum_v2or3(journal))
375 csum_size = sizeof(struct jbd2_journal_block_tail);
376
377 /*
378 * First job: lock down the current transaction and wait for
379 * all outstanding updates to complete.
380 */
381
382 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
383 if (journal->j_flags & JBD2_FLUSHED) {
384 jbd_debug(3, "super block updated\n");
385 mutex_lock_io(&journal->j_checkpoint_mutex);
386 /*
387 * We hold j_checkpoint_mutex so tail cannot change under us.
388 * We don't need any special data guarantees for writing sb
389 * since journal is empty and it is ok for write to be
390 * flushed only with transaction commit.
391 */
392 jbd2_journal_update_sb_log_tail(journal,
393 journal->j_tail_sequence,
394 journal->j_tail,
395 REQ_SYNC);
396 mutex_unlock(&journal->j_checkpoint_mutex);
397 } else {
398 jbd_debug(3, "superblock not updated\n");
399 }
400
401 J_ASSERT(journal->j_running_transaction != NULL);
402 J_ASSERT(journal->j_committing_transaction == NULL);
403
404 commit_transaction = journal->j_running_transaction;
405
406 trace_jbd2_start_commit(journal, commit_transaction);
407 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
408 commit_transaction->t_tid);
409
410 write_lock(&journal->j_state_lock);
411 J_ASSERT(commit_transaction->t_state == T_RUNNING);
412 commit_transaction->t_state = T_LOCKED;
413
414 trace_jbd2_commit_locking(journal, commit_transaction);
415 stats.run.rs_wait = commit_transaction->t_max_wait;
416 stats.run.rs_request_delay = 0;
417 stats.run.rs_locked = jiffies;
418 if (commit_transaction->t_requested)
419 stats.run.rs_request_delay =
420 jbd2_time_diff(commit_transaction->t_requested,
421 stats.run.rs_locked);
422 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
423 stats.run.rs_locked);
424
425 spin_lock(&commit_transaction->t_handle_lock);
426 while (atomic_read(&commit_transaction->t_updates)) {
427 DEFINE_WAIT(wait);
428
429 prepare_to_wait(&journal->j_wait_updates, &wait,
430 TASK_UNINTERRUPTIBLE);
431 if (atomic_read(&commit_transaction->t_updates)) {
432 spin_unlock(&commit_transaction->t_handle_lock);
433 write_unlock(&journal->j_state_lock);
434 schedule();
435 write_lock(&journal->j_state_lock);
436 spin_lock(&commit_transaction->t_handle_lock);
437 }
438 finish_wait(&journal->j_wait_updates, &wait);
439 }
440 spin_unlock(&commit_transaction->t_handle_lock);
441
442 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
443 journal->j_max_transaction_buffers);
444
445 /*
446 * First thing we are allowed to do is to discard any remaining
447 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
448 * that there are no such buffers: if a large filesystem
449 * operation like a truncate needs to split itself over multiple
450 * transactions, then it may try to do a jbd2_journal_restart() while
451 * there are still BJ_Reserved buffers outstanding. These must
452 * be released cleanly from the current transaction.
453 *
454 * In this case, the filesystem must still reserve write access
455 * again before modifying the buffer in the new transaction, but
456 * we do not require it to remember exactly which old buffers it
457 * has reserved. This is consistent with the existing behaviour
458 * that multiple jbd2_journal_get_write_access() calls to the same
459 * buffer are perfectly permissible.
460 */
461 while (commit_transaction->t_reserved_list) {
462 jh = commit_transaction->t_reserved_list;
463 JBUFFER_TRACE(jh, "reserved, unused: refile");
464 /*
465 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
466 * leave undo-committed data.
467 */
468 if (jh->b_committed_data) {
469 struct buffer_head *bh = jh2bh(jh);
470
471 jbd_lock_bh_state(bh);
472 jbd2_free(jh->b_committed_data, bh->b_size);
473 jh->b_committed_data = NULL;
474 jbd_unlock_bh_state(bh);
475 }
476 jbd2_journal_refile_buffer(journal, jh);
477 }
478
479 /*
480 * Now try to drop any written-back buffers from the journal's
481 * checkpoint lists. We do this *before* commit because it potentially
482 * frees some memory
483 */
484 spin_lock(&journal->j_list_lock);
485 __jbd2_journal_clean_checkpoint_list(journal, false);
486 spin_unlock(&journal->j_list_lock);
487
488 jbd_debug(3, "JBD2: commit phase 1\n");
489
490 /*
491 * Clear revoked flag to reflect there is no revoked buffers
492 * in the next transaction which is going to be started.
493 */
494 jbd2_clear_buffer_revoked_flags(journal);
495
496 /*
497 * Switch to a new revoke table.
498 */
499 jbd2_journal_switch_revoke_table(journal);
500
501 /*
502 * Reserved credits cannot be claimed anymore, free them
503 */
504 atomic_sub(atomic_read(&journal->j_reserved_credits),
505 &commit_transaction->t_outstanding_credits);
506
507 trace_jbd2_commit_flushing(journal, commit_transaction);
508 stats.run.rs_flushing = jiffies;
509 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
510 stats.run.rs_flushing);
511
512 commit_transaction->t_state = T_FLUSH;
513 journal->j_committing_transaction = commit_transaction;
514 journal->j_running_transaction = NULL;
515 start_time = ktime_get();
516 commit_transaction->t_log_start = journal->j_head;
517 wake_up(&journal->j_wait_transaction_locked);
518 write_unlock(&journal->j_state_lock);
519
520 jbd_debug(3, "JBD2: commit phase 2a\n");
521
522 /*
523 * Now start flushing things to disk, in the order they appear
524 * on the transaction lists. Data blocks go first.
525 */
526 err = journal_submit_data_buffers(journal, commit_transaction);
527 if (err)
528 jbd2_journal_abort(journal, err);
529
530 blk_start_plug(&plug);
531 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
532
533 jbd_debug(3, "JBD2: commit phase 2b\n");
534
535 /*
536 * Way to go: we have now written out all of the data for a
537 * transaction! Now comes the tricky part: we need to write out
538 * metadata. Loop over the transaction's entire buffer list:
539 */
540 write_lock(&journal->j_state_lock);
541 commit_transaction->t_state = T_COMMIT;
542 write_unlock(&journal->j_state_lock);
543
544 trace_jbd2_commit_logging(journal, commit_transaction);
545 stats.run.rs_logging = jiffies;
546 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
547 stats.run.rs_logging);
548 stats.run.rs_blocks =
549 atomic_read(&commit_transaction->t_outstanding_credits);
550 stats.run.rs_blocks_logged = 0;
551
552 J_ASSERT(commit_transaction->t_nr_buffers <=
553 atomic_read(&commit_transaction->t_outstanding_credits));
554
555 err = 0;
556 bufs = 0;
557 descriptor = NULL;
558 while (commit_transaction->t_buffers) {
559
560 /* Find the next buffer to be journaled... */
561
562 jh = commit_transaction->t_buffers;
563
564 /* If we're in abort mode, we just un-journal the buffer and
565 release it. */
566
567 if (is_journal_aborted(journal)) {
568 clear_buffer_jbddirty(jh2bh(jh));
569 JBUFFER_TRACE(jh, "journal is aborting: refile");
570 jbd2_buffer_abort_trigger(jh,
571 jh->b_frozen_data ?
572 jh->b_frozen_triggers :
573 jh->b_triggers);
574 jbd2_journal_refile_buffer(journal, jh);
575 /* If that was the last one, we need to clean up
576 * any descriptor buffers which may have been
577 * already allocated, even if we are now
578 * aborting. */
579 if (!commit_transaction->t_buffers)
580 goto start_journal_io;
581 continue;
582 }
583
584 /* Make sure we have a descriptor block in which to
585 record the metadata buffer. */
586
587 if (!descriptor) {
588 J_ASSERT (bufs == 0);
589
590 jbd_debug(4, "JBD2: get descriptor\n");
591
592 descriptor = jbd2_journal_get_descriptor_buffer(
593 commit_transaction,
594 JBD2_DESCRIPTOR_BLOCK);
595 if (!descriptor) {
596 jbd2_journal_abort(journal, -EIO);
597 continue;
598 }
599
600 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
601 (unsigned long long)descriptor->b_blocknr,
602 descriptor->b_data);
603 tagp = &descriptor->b_data[sizeof(journal_header_t)];
604 space_left = descriptor->b_size -
605 sizeof(journal_header_t);
606 first_tag = 1;
607 set_buffer_jwrite(descriptor);
608 set_buffer_dirty(descriptor);
609 wbuf[bufs++] = descriptor;
610
611 /* Record it so that we can wait for IO
612 completion later */
613 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
614 jbd2_file_log_bh(&log_bufs, descriptor);
615 }
616
617 /* Where is the buffer to be written? */
618
619 err = jbd2_journal_next_log_block(journal, &blocknr);
620 /* If the block mapping failed, just abandon the buffer
621 and repeat this loop: we'll fall into the
622 refile-on-abort condition above. */
623 if (err) {
624 jbd2_journal_abort(journal, err);
625 continue;
626 }
627
628 /*
629 * start_this_handle() uses t_outstanding_credits to determine
630 * the free space in the log, but this counter is changed
631 * by jbd2_journal_next_log_block() also.
632 */
633 atomic_dec(&commit_transaction->t_outstanding_credits);
634
635 /* Bump b_count to prevent truncate from stumbling over
636 the shadowed buffer! @@@ This can go if we ever get
637 rid of the shadow pairing of buffers. */
638 atomic_inc(&jh2bh(jh)->b_count);
639
640 /*
641 * Make a temporary IO buffer with which to write it out
642 * (this will requeue the metadata buffer to BJ_Shadow).
643 */
644 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
645 JBUFFER_TRACE(jh, "ph3: write metadata");
646 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
647 jh, &wbuf[bufs], blocknr);
648 if (flags < 0) {
649 jbd2_journal_abort(journal, flags);
650 continue;
651 }
652 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
653
654 /* Record the new block's tag in the current descriptor
655 buffer */
656
657 tag_flag = 0;
658 if (flags & 1)
659 tag_flag |= JBD2_FLAG_ESCAPE;
660 if (!first_tag)
661 tag_flag |= JBD2_FLAG_SAME_UUID;
662
663 tag = (journal_block_tag_t *) tagp;
664 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
665 tag->t_flags = cpu_to_be16(tag_flag);
666 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
667 commit_transaction->t_tid);
668 tagp += tag_bytes;
669 space_left -= tag_bytes;
670 bufs++;
671
672 if (first_tag) {
673 memcpy (tagp, journal->j_uuid, 16);
674 tagp += 16;
675 space_left -= 16;
676 first_tag = 0;
677 }
678
679 /* If there's no more to do, or if the descriptor is full,
680 let the IO rip! */
681
682 if (bufs == journal->j_wbufsize ||
683 commit_transaction->t_buffers == NULL ||
684 space_left < tag_bytes + 16 + csum_size) {
685
686 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
687
688 /* Write an end-of-descriptor marker before
689 submitting the IOs. "tag" still points to
690 the last tag we set up. */
691
692 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
693
694 jbd2_descriptor_block_csum_set(journal, descriptor);
695start_journal_io:
696 for (i = 0; i < bufs; i++) {
697 struct buffer_head *bh = wbuf[i];
698 /*
699 * Compute checksum.
700 */
701 if (jbd2_has_feature_checksum(journal)) {
702 crc32_sum =
703 jbd2_checksum_data(crc32_sum, bh);
704 }
705
706 lock_buffer(bh);
707 clear_buffer_dirty(bh);
708 set_buffer_uptodate(bh);
709 bh->b_end_io = journal_end_buffer_io_sync;
710 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
711 }
712 cond_resched();
713 stats.run.rs_blocks_logged += bufs;
714
715 /* Force a new descriptor to be generated next
716 time round the loop. */
717 descriptor = NULL;
718 bufs = 0;
719 }
720 }
721
722 err = journal_finish_inode_data_buffers(journal, commit_transaction);
723 if (err) {
724 printk(KERN_WARNING
725 "JBD2: Detected IO errors while flushing file data "
726 "on %s\n", journal->j_devname);
727 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
728 jbd2_journal_abort(journal, err);
729 err = 0;
730 }
731
732 /*
733 * Get current oldest transaction in the log before we issue flush
734 * to the filesystem device. After the flush we can be sure that
735 * blocks of all older transactions are checkpointed to persistent
736 * storage and we will be safe to update journal start in the
737 * superblock with the numbers we get here.
738 */
739 update_tail =
740 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
741
742 write_lock(&journal->j_state_lock);
743 if (update_tail) {
744 long freed = first_block - journal->j_tail;
745
746 if (first_block < journal->j_tail)
747 freed += journal->j_last - journal->j_first;
748 /* Update tail only if we free significant amount of space */
749 if (freed < journal->j_maxlen / 4)
750 update_tail = 0;
751 }
752 J_ASSERT(commit_transaction->t_state == T_COMMIT);
753 commit_transaction->t_state = T_COMMIT_DFLUSH;
754 write_unlock(&journal->j_state_lock);
755
756 /*
757 * If the journal is not located on the file system device,
758 * then we must flush the file system device before we issue
759 * the commit record
760 */
761 if (commit_transaction->t_need_data_flush &&
762 (journal->j_fs_dev != journal->j_dev) &&
763 (journal->j_flags & JBD2_BARRIER))
764 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
765
766 /* Done it all: now write the commit record asynchronously. */
767 if (jbd2_has_feature_async_commit(journal)) {
768 err = journal_submit_commit_record(journal, commit_transaction,
769 &cbh, crc32_sum);
770 if (err)
771 __jbd2_journal_abort_hard(journal);
772 }
773
774 blk_finish_plug(&plug);
775
776 /* Lo and behold: we have just managed to send a transaction to
777 the log. Before we can commit it, wait for the IO so far to
778 complete. Control buffers being written are on the
779 transaction's t_log_list queue, and metadata buffers are on
780 the io_bufs list.
781
782 Wait for the buffers in reverse order. That way we are
783 less likely to be woken up until all IOs have completed, and
784 so we incur less scheduling load.
785 */
786
787 jbd_debug(3, "JBD2: commit phase 3\n");
788
789 while (!list_empty(&io_bufs)) {
790 struct buffer_head *bh = list_entry(io_bufs.prev,
791 struct buffer_head,
792 b_assoc_buffers);
793
794 wait_on_buffer(bh);
795 cond_resched();
796
797 if (unlikely(!buffer_uptodate(bh)))
798 err = -EIO;
799 jbd2_unfile_log_bh(bh);
800
801 /*
802 * The list contains temporary buffer heads created by
803 * jbd2_journal_write_metadata_buffer().
804 */
805 BUFFER_TRACE(bh, "dumping temporary bh");
806 __brelse(bh);
807 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
808 free_buffer_head(bh);
809
810 /* We also have to refile the corresponding shadowed buffer */
811 jh = commit_transaction->t_shadow_list->b_tprev;
812 bh = jh2bh(jh);
813 clear_buffer_jwrite(bh);
814 J_ASSERT_BH(bh, buffer_jbddirty(bh));
815 J_ASSERT_BH(bh, !buffer_shadow(bh));
816
817 /* The metadata is now released for reuse, but we need
818 to remember it against this transaction so that when
819 we finally commit, we can do any checkpointing
820 required. */
821 JBUFFER_TRACE(jh, "file as BJ_Forget");
822 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
823 JBUFFER_TRACE(jh, "brelse shadowed buffer");
824 __brelse(bh);
825 }
826
827 J_ASSERT (commit_transaction->t_shadow_list == NULL);
828
829 jbd_debug(3, "JBD2: commit phase 4\n");
830
831 /* Here we wait for the revoke record and descriptor record buffers */
832 while (!list_empty(&log_bufs)) {
833 struct buffer_head *bh;
834
835 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
836 wait_on_buffer(bh);
837 cond_resched();
838
839 if (unlikely(!buffer_uptodate(bh)))
840 err = -EIO;
841
842 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
843 clear_buffer_jwrite(bh);
844 jbd2_unfile_log_bh(bh);
845 __brelse(bh); /* One for getblk */
846 /* AKPM: bforget here */
847 }
848
849 if (err)
850 jbd2_journal_abort(journal, err);
851
852 jbd_debug(3, "JBD2: commit phase 5\n");
853 write_lock(&journal->j_state_lock);
854 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
855 commit_transaction->t_state = T_COMMIT_JFLUSH;
856 write_unlock(&journal->j_state_lock);
857
858 if (!jbd2_has_feature_async_commit(journal)) {
859 err = journal_submit_commit_record(journal, commit_transaction,
860 &cbh, crc32_sum);
861 if (err)
862 __jbd2_journal_abort_hard(journal);
863 }
864 if (cbh)
865 err = journal_wait_on_commit_record(journal, cbh);
866 if (jbd2_has_feature_async_commit(journal) &&
867 journal->j_flags & JBD2_BARRIER) {
868 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
869 }
870
871 if (err)
872 jbd2_journal_abort(journal, err);
873
874 /*
875 * Now disk caches for filesystem device are flushed so we are safe to
876 * erase checkpointed transactions from the log by updating journal
877 * superblock.
878 */
879 if (update_tail)
880 jbd2_update_log_tail(journal, first_tid, first_block);
881
882 /* End of a transaction! Finally, we can do checkpoint
883 processing: any buffers committed as a result of this
884 transaction can be removed from any checkpoint list it was on
885 before. */
886
887 jbd_debug(3, "JBD2: commit phase 6\n");
888
889 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
890 J_ASSERT(commit_transaction->t_buffers == NULL);
891 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
892 J_ASSERT(commit_transaction->t_shadow_list == NULL);
893
894restart_loop:
895 /*
896 * As there are other places (journal_unmap_buffer()) adding buffers
897 * to this list we have to be careful and hold the j_list_lock.
898 */
899 spin_lock(&journal->j_list_lock);
900 while (commit_transaction->t_forget) {
901 transaction_t *cp_transaction;
902 struct buffer_head *bh;
903 int try_to_free = 0;
904
905 jh = commit_transaction->t_forget;
906 spin_unlock(&journal->j_list_lock);
907 bh = jh2bh(jh);
908 /*
909 * Get a reference so that bh cannot be freed before we are
910 * done with it.
911 */
912 get_bh(bh);
913 jbd_lock_bh_state(bh);
914 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
915
916 /*
917 * If there is undo-protected committed data against
918 * this buffer, then we can remove it now. If it is a
919 * buffer needing such protection, the old frozen_data
920 * field now points to a committed version of the
921 * buffer, so rotate that field to the new committed
922 * data.
923 *
924 * Otherwise, we can just throw away the frozen data now.
925 *
926 * We also know that the frozen data has already fired
927 * its triggers if they exist, so we can clear that too.
928 */
929 if (jh->b_committed_data) {
930 jbd2_free(jh->b_committed_data, bh->b_size);
931 jh->b_committed_data = NULL;
932 if (jh->b_frozen_data) {
933 jh->b_committed_data = jh->b_frozen_data;
934 jh->b_frozen_data = NULL;
935 jh->b_frozen_triggers = NULL;
936 }
937 } else if (jh->b_frozen_data) {
938 jbd2_free(jh->b_frozen_data, bh->b_size);
939 jh->b_frozen_data = NULL;
940 jh->b_frozen_triggers = NULL;
941 }
942
943 spin_lock(&journal->j_list_lock);
944 cp_transaction = jh->b_cp_transaction;
945 if (cp_transaction) {
946 JBUFFER_TRACE(jh, "remove from old cp transaction");
947 cp_transaction->t_chp_stats.cs_dropped++;
948 __jbd2_journal_remove_checkpoint(jh);
949 }
950
951 /* Only re-checkpoint the buffer_head if it is marked
952 * dirty. If the buffer was added to the BJ_Forget list
953 * by jbd2_journal_forget, it may no longer be dirty and
954 * there's no point in keeping a checkpoint record for
955 * it. */
956
957 /*
958 * A buffer which has been freed while still being journaled by
959 * a previous transaction.
960 */
961 if (buffer_freed(bh)) {
962 /*
963 * If the running transaction is the one containing
964 * "add to orphan" operation (b_next_transaction !=
965 * NULL), we have to wait for that transaction to
966 * commit before we can really get rid of the buffer.
967 * So just clear b_modified to not confuse transaction
968 * credit accounting and refile the buffer to
969 * BJ_Forget of the running transaction. If the just
970 * committed transaction contains "add to orphan"
971 * operation, we can completely invalidate the buffer
972 * now. We are rather through in that since the
973 * buffer may be still accessible when blocksize <
974 * pagesize and it is attached to the last partial
975 * page.
976 */
977 jh->b_modified = 0;
978 if (!jh->b_next_transaction) {
979 clear_buffer_freed(bh);
980 clear_buffer_jbddirty(bh);
981 clear_buffer_mapped(bh);
982 clear_buffer_new(bh);
983 clear_buffer_req(bh);
984 bh->b_bdev = NULL;
985 }
986 }
987
988 if (buffer_jbddirty(bh)) {
989 JBUFFER_TRACE(jh, "add to new checkpointing trans");
990 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
991 if (is_journal_aborted(journal))
992 clear_buffer_jbddirty(bh);
993 } else {
994 J_ASSERT_BH(bh, !buffer_dirty(bh));
995 /*
996 * The buffer on BJ_Forget list and not jbddirty means
997 * it has been freed by this transaction and hence it
998 * could not have been reallocated until this
999 * transaction has committed. *BUT* it could be
1000 * reallocated once we have written all the data to
1001 * disk and before we process the buffer on BJ_Forget
1002 * list.
1003 */
1004 if (!jh->b_next_transaction)
1005 try_to_free = 1;
1006 }
1007 JBUFFER_TRACE(jh, "refile or unfile buffer");
1008 __jbd2_journal_refile_buffer(jh);
1009 jbd_unlock_bh_state(bh);
1010 if (try_to_free)
1011 release_buffer_page(bh); /* Drops bh reference */
1012 else
1013 __brelse(bh);
1014 cond_resched_lock(&journal->j_list_lock);
1015 }
1016 spin_unlock(&journal->j_list_lock);
1017 /*
1018 * This is a bit sleazy. We use j_list_lock to protect transition
1019 * of a transaction into T_FINISHED state and calling
1020 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1021 * other checkpointing code processing the transaction...
1022 */
1023 write_lock(&journal->j_state_lock);
1024 spin_lock(&journal->j_list_lock);
1025 /*
1026 * Now recheck if some buffers did not get attached to the transaction
1027 * while the lock was dropped...
1028 */
1029 if (commit_transaction->t_forget) {
1030 spin_unlock(&journal->j_list_lock);
1031 write_unlock(&journal->j_state_lock);
1032 goto restart_loop;
1033 }
1034
1035 /* Add the transaction to the checkpoint list
1036 * __journal_remove_checkpoint() can not destroy transaction
1037 * under us because it is not marked as T_FINISHED yet */
1038 if (journal->j_checkpoint_transactions == NULL) {
1039 journal->j_checkpoint_transactions = commit_transaction;
1040 commit_transaction->t_cpnext = commit_transaction;
1041 commit_transaction->t_cpprev = commit_transaction;
1042 } else {
1043 commit_transaction->t_cpnext =
1044 journal->j_checkpoint_transactions;
1045 commit_transaction->t_cpprev =
1046 commit_transaction->t_cpnext->t_cpprev;
1047 commit_transaction->t_cpnext->t_cpprev =
1048 commit_transaction;
1049 commit_transaction->t_cpprev->t_cpnext =
1050 commit_transaction;
1051 }
1052 spin_unlock(&journal->j_list_lock);
1053
1054 /* Done with this transaction! */
1055
1056 jbd_debug(3, "JBD2: commit phase 7\n");
1057
1058 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1059
1060 commit_transaction->t_start = jiffies;
1061 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1062 commit_transaction->t_start);
1063
1064 /*
1065 * File the transaction statistics
1066 */
1067 stats.ts_tid = commit_transaction->t_tid;
1068 stats.run.rs_handle_count =
1069 atomic_read(&commit_transaction->t_handle_count);
1070 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1071 commit_transaction->t_tid, &stats.run);
1072 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1073
1074 commit_transaction->t_state = T_COMMIT_CALLBACK;
1075 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1076 journal->j_commit_sequence = commit_transaction->t_tid;
1077 journal->j_committing_transaction = NULL;
1078 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1079
1080 /*
1081 * weight the commit time higher than the average time so we don't
1082 * react too strongly to vast changes in the commit time
1083 */
1084 if (likely(journal->j_average_commit_time))
1085 journal->j_average_commit_time = (commit_time +
1086 journal->j_average_commit_time*3) / 4;
1087 else
1088 journal->j_average_commit_time = commit_time;
1089
1090 write_unlock(&journal->j_state_lock);
1091
1092 if (journal->j_commit_callback)
1093 journal->j_commit_callback(journal, commit_transaction);
1094
1095 trace_jbd2_end_commit(journal, commit_transaction);
1096 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1097 journal->j_commit_sequence, journal->j_tail_sequence);
1098
1099 write_lock(&journal->j_state_lock);
1100 spin_lock(&journal->j_list_lock);
1101 commit_transaction->t_state = T_FINISHED;
1102 /* Check if the transaction can be dropped now that we are finished */
1103 if (commit_transaction->t_checkpoint_list == NULL &&
1104 commit_transaction->t_checkpoint_io_list == NULL) {
1105 __jbd2_journal_drop_transaction(journal, commit_transaction);
1106 jbd2_journal_free_transaction(commit_transaction);
1107 }
1108 spin_unlock(&journal->j_list_lock);
1109 write_unlock(&journal->j_state_lock);
1110 wake_up(&journal->j_wait_done_commit);
1111
1112 /*
1113 * Calculate overall stats
1114 */
1115 spin_lock(&journal->j_history_lock);
1116 journal->j_stats.ts_tid++;
1117 journal->j_stats.ts_requested += stats.ts_requested;
1118 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1119 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1120 journal->j_stats.run.rs_running += stats.run.rs_running;
1121 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1122 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1123 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1124 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1125 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1126 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1127 spin_unlock(&journal->j_history_lock);
1128}
1// 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 */
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(struct jbd2_inode *jinode)
211{
212
213 if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
214 return 0;
215
216 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
217 return jbd2_journal_submit_inode_data_buffers(jinode);
218
219}
220EXPORT_SYMBOL(jbd2_submit_inode_data);
221
222int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
223{
224 if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
225 !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
226 return 0;
227 return filemap_fdatawait_range_keep_errors(
228 jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
229 jinode->i_dirty_end);
230}
231EXPORT_SYMBOL(jbd2_wait_inode_data);
232
233/*
234 * Submit all the data buffers of inode associated with the transaction to
235 * disk.
236 *
237 * We are in a committing transaction. Therefore no new inode can be added to
238 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
239 * operate on from being released while we write out pages.
240 */
241static int journal_submit_data_buffers(journal_t *journal,
242 transaction_t *commit_transaction)
243{
244 struct jbd2_inode *jinode;
245 int err, ret = 0;
246
247 spin_lock(&journal->j_list_lock);
248 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
249 if (!(jinode->i_flags & JI_WRITE_DATA))
250 continue;
251 jinode->i_flags |= JI_COMMIT_RUNNING;
252 spin_unlock(&journal->j_list_lock);
253 /* submit the inode data buffers. */
254 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
255 if (journal->j_submit_inode_data_buffers) {
256 err = journal->j_submit_inode_data_buffers(jinode);
257 if (!ret)
258 ret = err;
259 }
260 spin_lock(&journal->j_list_lock);
261 J_ASSERT(jinode->i_transaction == commit_transaction);
262 jinode->i_flags &= ~JI_COMMIT_RUNNING;
263 smp_mb();
264 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
265 }
266 spin_unlock(&journal->j_list_lock);
267 return ret;
268}
269
270int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
271{
272 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
273
274 return filemap_fdatawait_range_keep_errors(mapping,
275 jinode->i_dirty_start,
276 jinode->i_dirty_end);
277}
278
279/*
280 * Wait for data submitted for writeout, refile inodes to proper
281 * transaction if needed.
282 *
283 */
284static int journal_finish_inode_data_buffers(journal_t *journal,
285 transaction_t *commit_transaction)
286{
287 struct jbd2_inode *jinode, *next_i;
288 int err, ret = 0;
289
290 /* For locking, see the comment in journal_submit_data_buffers() */
291 spin_lock(&journal->j_list_lock);
292 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
293 if (!(jinode->i_flags & JI_WAIT_DATA))
294 continue;
295 jinode->i_flags |= JI_COMMIT_RUNNING;
296 spin_unlock(&journal->j_list_lock);
297 /* wait for the inode data buffers writeout. */
298 if (journal->j_finish_inode_data_buffers) {
299 err = journal->j_finish_inode_data_buffers(jinode);
300 if (!ret)
301 ret = err;
302 }
303 spin_lock(&journal->j_list_lock);
304 jinode->i_flags &= ~JI_COMMIT_RUNNING;
305 smp_mb();
306 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
307 }
308
309 /* Now refile inode to proper lists */
310 list_for_each_entry_safe(jinode, next_i,
311 &commit_transaction->t_inode_list, i_list) {
312 list_del(&jinode->i_list);
313 if (jinode->i_next_transaction) {
314 jinode->i_transaction = jinode->i_next_transaction;
315 jinode->i_next_transaction = NULL;
316 list_add(&jinode->i_list,
317 &jinode->i_transaction->t_inode_list);
318 } else {
319 jinode->i_transaction = NULL;
320 jinode->i_dirty_start = 0;
321 jinode->i_dirty_end = 0;
322 }
323 }
324 spin_unlock(&journal->j_list_lock);
325
326 return ret;
327}
328
329static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
330{
331 struct page *page = bh->b_page;
332 char *addr;
333 __u32 checksum;
334
335 addr = kmap_atomic(page);
336 checksum = crc32_be(crc32_sum,
337 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
338 kunmap_atomic(addr);
339
340 return checksum;
341}
342
343static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
344 unsigned long long block)
345{
346 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
347 if (jbd2_has_feature_64bit(j))
348 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
349}
350
351static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
352 struct buffer_head *bh, __u32 sequence)
353{
354 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
355 struct page *page = bh->b_page;
356 __u8 *addr;
357 __u32 csum32;
358 __be32 seq;
359
360 if (!jbd2_journal_has_csum_v2or3(j))
361 return;
362
363 seq = cpu_to_be32(sequence);
364 addr = kmap_atomic(page);
365 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
366 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
367 bh->b_size);
368 kunmap_atomic(addr);
369
370 if (jbd2_has_feature_csum3(j))
371 tag3->t_checksum = cpu_to_be32(csum32);
372 else
373 tag->t_checksum = cpu_to_be16(csum32);
374}
375/*
376 * jbd2_journal_commit_transaction
377 *
378 * The primary function for committing a transaction to the log. This
379 * function is called by the journal thread to begin a complete commit.
380 */
381void jbd2_journal_commit_transaction(journal_t *journal)
382{
383 struct transaction_stats_s stats;
384 transaction_t *commit_transaction;
385 struct journal_head *jh;
386 struct buffer_head *descriptor;
387 struct buffer_head **wbuf = journal->j_wbuf;
388 int bufs;
389 int flags;
390 int err;
391 unsigned long long blocknr;
392 ktime_t start_time;
393 u64 commit_time;
394 char *tagp = NULL;
395 journal_block_tag_t *tag = NULL;
396 int space_left = 0;
397 int first_tag = 0;
398 int tag_flag;
399 int i;
400 int tag_bytes = journal_tag_bytes(journal);
401 struct buffer_head *cbh = NULL; /* For transactional checksums */
402 __u32 crc32_sum = ~0;
403 struct blk_plug plug;
404 /* Tail of the journal */
405 unsigned long first_block;
406 tid_t first_tid;
407 int update_tail;
408 int csum_size = 0;
409 LIST_HEAD(io_bufs);
410 LIST_HEAD(log_bufs);
411
412 if (jbd2_journal_has_csum_v2or3(journal))
413 csum_size = sizeof(struct jbd2_journal_block_tail);
414
415 /*
416 * First job: lock down the current transaction and wait for
417 * all outstanding updates to complete.
418 */
419
420 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
421 if (journal->j_flags & JBD2_FLUSHED) {
422 jbd_debug(3, "super block updated\n");
423 mutex_lock_io(&journal->j_checkpoint_mutex);
424 /*
425 * We hold j_checkpoint_mutex so tail cannot change under us.
426 * We don't need any special data guarantees for writing sb
427 * since journal is empty and it is ok for write to be
428 * flushed only with transaction commit.
429 */
430 jbd2_journal_update_sb_log_tail(journal,
431 journal->j_tail_sequence,
432 journal->j_tail,
433 REQ_SYNC);
434 mutex_unlock(&journal->j_checkpoint_mutex);
435 } else {
436 jbd_debug(3, "superblock not updated\n");
437 }
438
439 J_ASSERT(journal->j_running_transaction != NULL);
440 J_ASSERT(journal->j_committing_transaction == NULL);
441
442 write_lock(&journal->j_state_lock);
443 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
444 while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
445 DEFINE_WAIT(wait);
446
447 prepare_to_wait(&journal->j_fc_wait, &wait,
448 TASK_UNINTERRUPTIBLE);
449 write_unlock(&journal->j_state_lock);
450 schedule();
451 write_lock(&journal->j_state_lock);
452 finish_wait(&journal->j_fc_wait, &wait);
453 /*
454 * TODO: by blocking fast commits here, we are increasing
455 * fsync() latency slightly. Strictly speaking, we don't need
456 * to block fast commits until the transaction enters T_FLUSH
457 * state. So an optimization is possible where we block new fast
458 * commits here and wait for existing ones to complete
459 * just before we enter T_FLUSH. That way, the existing fast
460 * commits and this full commit can proceed parallely.
461 */
462 }
463 write_unlock(&journal->j_state_lock);
464
465 commit_transaction = journal->j_running_transaction;
466
467 trace_jbd2_start_commit(journal, commit_transaction);
468 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
469 commit_transaction->t_tid);
470
471 write_lock(&journal->j_state_lock);
472 journal->j_fc_off = 0;
473 J_ASSERT(commit_transaction->t_state == T_RUNNING);
474 commit_transaction->t_state = T_LOCKED;
475
476 trace_jbd2_commit_locking(journal, commit_transaction);
477 stats.run.rs_wait = commit_transaction->t_max_wait;
478 stats.run.rs_request_delay = 0;
479 stats.run.rs_locked = jiffies;
480 if (commit_transaction->t_requested)
481 stats.run.rs_request_delay =
482 jbd2_time_diff(commit_transaction->t_requested,
483 stats.run.rs_locked);
484 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
485 stats.run.rs_locked);
486
487 spin_lock(&commit_transaction->t_handle_lock);
488 while (atomic_read(&commit_transaction->t_updates)) {
489 DEFINE_WAIT(wait);
490
491 prepare_to_wait(&journal->j_wait_updates, &wait,
492 TASK_UNINTERRUPTIBLE);
493 if (atomic_read(&commit_transaction->t_updates)) {
494 spin_unlock(&commit_transaction->t_handle_lock);
495 write_unlock(&journal->j_state_lock);
496 schedule();
497 write_lock(&journal->j_state_lock);
498 spin_lock(&commit_transaction->t_handle_lock);
499 }
500 finish_wait(&journal->j_wait_updates, &wait);
501 }
502 spin_unlock(&commit_transaction->t_handle_lock);
503 commit_transaction->t_state = T_SWITCH;
504 write_unlock(&journal->j_state_lock);
505
506 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
507 journal->j_max_transaction_buffers);
508
509 /*
510 * First thing we are allowed to do is to discard any remaining
511 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
512 * that there are no such buffers: if a large filesystem
513 * operation like a truncate needs to split itself over multiple
514 * transactions, then it may try to do a jbd2_journal_restart() while
515 * there are still BJ_Reserved buffers outstanding. These must
516 * be released cleanly from the current transaction.
517 *
518 * In this case, the filesystem must still reserve write access
519 * again before modifying the buffer in the new transaction, but
520 * we do not require it to remember exactly which old buffers it
521 * has reserved. This is consistent with the existing behaviour
522 * that multiple jbd2_journal_get_write_access() calls to the same
523 * buffer are perfectly permissible.
524 */
525 while (commit_transaction->t_reserved_list) {
526 jh = commit_transaction->t_reserved_list;
527 JBUFFER_TRACE(jh, "reserved, unused: refile");
528 /*
529 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
530 * leave undo-committed data.
531 */
532 if (jh->b_committed_data) {
533 struct buffer_head *bh = jh2bh(jh);
534
535 spin_lock(&jh->b_state_lock);
536 jbd2_free(jh->b_committed_data, bh->b_size);
537 jh->b_committed_data = NULL;
538 spin_unlock(&jh->b_state_lock);
539 }
540 jbd2_journal_refile_buffer(journal, jh);
541 }
542
543 /*
544 * Now try to drop any written-back buffers from the journal's
545 * checkpoint lists. We do this *before* commit because it potentially
546 * frees some memory
547 */
548 spin_lock(&journal->j_list_lock);
549 __jbd2_journal_clean_checkpoint_list(journal, false);
550 spin_unlock(&journal->j_list_lock);
551
552 jbd_debug(3, "JBD2: commit phase 1\n");
553
554 /*
555 * Clear revoked flag to reflect there is no revoked buffers
556 * in the next transaction which is going to be started.
557 */
558 jbd2_clear_buffer_revoked_flags(journal);
559
560 /*
561 * Switch to a new revoke table.
562 */
563 jbd2_journal_switch_revoke_table(journal);
564
565 /*
566 * Reserved credits cannot be claimed anymore, free them
567 */
568 atomic_sub(atomic_read(&journal->j_reserved_credits),
569 &commit_transaction->t_outstanding_credits);
570
571 write_lock(&journal->j_state_lock);
572 trace_jbd2_commit_flushing(journal, commit_transaction);
573 stats.run.rs_flushing = jiffies;
574 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
575 stats.run.rs_flushing);
576
577 commit_transaction->t_state = T_FLUSH;
578 journal->j_committing_transaction = commit_transaction;
579 journal->j_running_transaction = NULL;
580 start_time = ktime_get();
581 commit_transaction->t_log_start = journal->j_head;
582 wake_up(&journal->j_wait_transaction_locked);
583 write_unlock(&journal->j_state_lock);
584
585 jbd_debug(3, "JBD2: commit phase 2a\n");
586
587 /*
588 * Now start flushing things to disk, in the order they appear
589 * on the transaction lists. Data blocks go first.
590 */
591 err = journal_submit_data_buffers(journal, commit_transaction);
592 if (err)
593 jbd2_journal_abort(journal, err);
594
595 blk_start_plug(&plug);
596 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
597
598 jbd_debug(3, "JBD2: commit phase 2b\n");
599
600 /*
601 * Way to go: we have now written out all of the data for a
602 * transaction! Now comes the tricky part: we need to write out
603 * metadata. Loop over the transaction's entire buffer list:
604 */
605 write_lock(&journal->j_state_lock);
606 commit_transaction->t_state = T_COMMIT;
607 write_unlock(&journal->j_state_lock);
608
609 trace_jbd2_commit_logging(journal, commit_transaction);
610 stats.run.rs_logging = jiffies;
611 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
612 stats.run.rs_logging);
613 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
614 stats.run.rs_blocks_logged = 0;
615
616 J_ASSERT(commit_transaction->t_nr_buffers <=
617 atomic_read(&commit_transaction->t_outstanding_credits));
618
619 err = 0;
620 bufs = 0;
621 descriptor = NULL;
622 while (commit_transaction->t_buffers) {
623
624 /* Find the next buffer to be journaled... */
625
626 jh = commit_transaction->t_buffers;
627
628 /* If we're in abort mode, we just un-journal the buffer and
629 release it. */
630
631 if (is_journal_aborted(journal)) {
632 clear_buffer_jbddirty(jh2bh(jh));
633 JBUFFER_TRACE(jh, "journal is aborting: refile");
634 jbd2_buffer_abort_trigger(jh,
635 jh->b_frozen_data ?
636 jh->b_frozen_triggers :
637 jh->b_triggers);
638 jbd2_journal_refile_buffer(journal, jh);
639 /* If that was the last one, we need to clean up
640 * any descriptor buffers which may have been
641 * already allocated, even if we are now
642 * aborting. */
643 if (!commit_transaction->t_buffers)
644 goto start_journal_io;
645 continue;
646 }
647
648 /* Make sure we have a descriptor block in which to
649 record the metadata buffer. */
650
651 if (!descriptor) {
652 J_ASSERT (bufs == 0);
653
654 jbd_debug(4, "JBD2: get descriptor\n");
655
656 descriptor = jbd2_journal_get_descriptor_buffer(
657 commit_transaction,
658 JBD2_DESCRIPTOR_BLOCK);
659 if (!descriptor) {
660 jbd2_journal_abort(journal, -EIO);
661 continue;
662 }
663
664 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
665 (unsigned long long)descriptor->b_blocknr,
666 descriptor->b_data);
667 tagp = &descriptor->b_data[sizeof(journal_header_t)];
668 space_left = descriptor->b_size -
669 sizeof(journal_header_t);
670 first_tag = 1;
671 set_buffer_jwrite(descriptor);
672 set_buffer_dirty(descriptor);
673 wbuf[bufs++] = descriptor;
674
675 /* Record it so that we can wait for IO
676 completion later */
677 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
678 jbd2_file_log_bh(&log_bufs, descriptor);
679 }
680
681 /* Where is the buffer to be written? */
682
683 err = jbd2_journal_next_log_block(journal, &blocknr);
684 /* If the block mapping failed, just abandon the buffer
685 and repeat this loop: we'll fall into the
686 refile-on-abort condition above. */
687 if (err) {
688 jbd2_journal_abort(journal, err);
689 continue;
690 }
691
692 /*
693 * start_this_handle() uses t_outstanding_credits to determine
694 * the free space in the log.
695 */
696 atomic_dec(&commit_transaction->t_outstanding_credits);
697
698 /* Bump b_count to prevent truncate from stumbling over
699 the shadowed buffer! @@@ This can go if we ever get
700 rid of the shadow pairing of buffers. */
701 atomic_inc(&jh2bh(jh)->b_count);
702
703 /*
704 * Make a temporary IO buffer with which to write it out
705 * (this will requeue the metadata buffer to BJ_Shadow).
706 */
707 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
708 JBUFFER_TRACE(jh, "ph3: write metadata");
709 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
710 jh, &wbuf[bufs], blocknr);
711 if (flags < 0) {
712 jbd2_journal_abort(journal, flags);
713 continue;
714 }
715 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
716
717 /* Record the new block's tag in the current descriptor
718 buffer */
719
720 tag_flag = 0;
721 if (flags & 1)
722 tag_flag |= JBD2_FLAG_ESCAPE;
723 if (!first_tag)
724 tag_flag |= JBD2_FLAG_SAME_UUID;
725
726 tag = (journal_block_tag_t *) tagp;
727 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
728 tag->t_flags = cpu_to_be16(tag_flag);
729 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
730 commit_transaction->t_tid);
731 tagp += tag_bytes;
732 space_left -= tag_bytes;
733 bufs++;
734
735 if (first_tag) {
736 memcpy (tagp, journal->j_uuid, 16);
737 tagp += 16;
738 space_left -= 16;
739 first_tag = 0;
740 }
741
742 /* If there's no more to do, or if the descriptor is full,
743 let the IO rip! */
744
745 if (bufs == journal->j_wbufsize ||
746 commit_transaction->t_buffers == NULL ||
747 space_left < tag_bytes + 16 + csum_size) {
748
749 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
750
751 /* Write an end-of-descriptor marker before
752 submitting the IOs. "tag" still points to
753 the last tag we set up. */
754
755 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
756start_journal_io:
757 if (descriptor)
758 jbd2_descriptor_block_csum_set(journal,
759 descriptor);
760
761 for (i = 0; i < bufs; i++) {
762 struct buffer_head *bh = wbuf[i];
763 /*
764 * Compute checksum.
765 */
766 if (jbd2_has_feature_checksum(journal)) {
767 crc32_sum =
768 jbd2_checksum_data(crc32_sum, bh);
769 }
770
771 lock_buffer(bh);
772 clear_buffer_dirty(bh);
773 set_buffer_uptodate(bh);
774 bh->b_end_io = journal_end_buffer_io_sync;
775 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
776 }
777 cond_resched();
778
779 /* Force a new descriptor to be generated next
780 time round the loop. */
781 descriptor = NULL;
782 bufs = 0;
783 }
784 }
785
786 err = journal_finish_inode_data_buffers(journal, commit_transaction);
787 if (err) {
788 printk(KERN_WARNING
789 "JBD2: Detected IO errors while flushing file data "
790 "on %s\n", journal->j_devname);
791 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
792 jbd2_journal_abort(journal, err);
793 err = 0;
794 }
795
796 /*
797 * Get current oldest transaction in the log before we issue flush
798 * to the filesystem device. After the flush we can be sure that
799 * blocks of all older transactions are checkpointed to persistent
800 * storage and we will be safe to update journal start in the
801 * superblock with the numbers we get here.
802 */
803 update_tail =
804 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
805
806 write_lock(&journal->j_state_lock);
807 if (update_tail) {
808 long freed = first_block - journal->j_tail;
809
810 if (first_block < journal->j_tail)
811 freed += journal->j_last - journal->j_first;
812 /* Update tail only if we free significant amount of space */
813 if (freed < jbd2_journal_get_max_txn_bufs(journal))
814 update_tail = 0;
815 }
816 J_ASSERT(commit_transaction->t_state == T_COMMIT);
817 commit_transaction->t_state = T_COMMIT_DFLUSH;
818 write_unlock(&journal->j_state_lock);
819
820 /*
821 * If the journal is not located on the file system device,
822 * then we must flush the file system device before we issue
823 * the commit record
824 */
825 if (commit_transaction->t_need_data_flush &&
826 (journal->j_fs_dev != journal->j_dev) &&
827 (journal->j_flags & JBD2_BARRIER))
828 blkdev_issue_flush(journal->j_fs_dev);
829
830 /* Done it all: now write the commit record asynchronously. */
831 if (jbd2_has_feature_async_commit(journal)) {
832 err = journal_submit_commit_record(journal, commit_transaction,
833 &cbh, crc32_sum);
834 if (err)
835 jbd2_journal_abort(journal, err);
836 }
837
838 blk_finish_plug(&plug);
839
840 /* Lo and behold: we have just managed to send a transaction to
841 the log. Before we can commit it, wait for the IO so far to
842 complete. Control buffers being written are on the
843 transaction's t_log_list queue, and metadata buffers are on
844 the io_bufs list.
845
846 Wait for the buffers in reverse order. That way we are
847 less likely to be woken up until all IOs have completed, and
848 so we incur less scheduling load.
849 */
850
851 jbd_debug(3, "JBD2: commit phase 3\n");
852
853 while (!list_empty(&io_bufs)) {
854 struct buffer_head *bh = list_entry(io_bufs.prev,
855 struct buffer_head,
856 b_assoc_buffers);
857
858 wait_on_buffer(bh);
859 cond_resched();
860
861 if (unlikely(!buffer_uptodate(bh)))
862 err = -EIO;
863 jbd2_unfile_log_bh(bh);
864 stats.run.rs_blocks_logged++;
865
866 /*
867 * The list contains temporary buffer heads created by
868 * jbd2_journal_write_metadata_buffer().
869 */
870 BUFFER_TRACE(bh, "dumping temporary bh");
871 __brelse(bh);
872 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
873 free_buffer_head(bh);
874
875 /* We also have to refile the corresponding shadowed buffer */
876 jh = commit_transaction->t_shadow_list->b_tprev;
877 bh = jh2bh(jh);
878 clear_buffer_jwrite(bh);
879 J_ASSERT_BH(bh, buffer_jbddirty(bh));
880 J_ASSERT_BH(bh, !buffer_shadow(bh));
881
882 /* The metadata is now released for reuse, but we need
883 to remember it against this transaction so that when
884 we finally commit, we can do any checkpointing
885 required. */
886 JBUFFER_TRACE(jh, "file as BJ_Forget");
887 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
888 JBUFFER_TRACE(jh, "brelse shadowed buffer");
889 __brelse(bh);
890 }
891
892 J_ASSERT (commit_transaction->t_shadow_list == NULL);
893
894 jbd_debug(3, "JBD2: commit phase 4\n");
895
896 /* Here we wait for the revoke record and descriptor record buffers */
897 while (!list_empty(&log_bufs)) {
898 struct buffer_head *bh;
899
900 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
901 wait_on_buffer(bh);
902 cond_resched();
903
904 if (unlikely(!buffer_uptodate(bh)))
905 err = -EIO;
906
907 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
908 clear_buffer_jwrite(bh);
909 jbd2_unfile_log_bh(bh);
910 stats.run.rs_blocks_logged++;
911 __brelse(bh); /* One for getblk */
912 /* AKPM: bforget here */
913 }
914
915 if (err)
916 jbd2_journal_abort(journal, err);
917
918 jbd_debug(3, "JBD2: commit phase 5\n");
919 write_lock(&journal->j_state_lock);
920 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
921 commit_transaction->t_state = T_COMMIT_JFLUSH;
922 write_unlock(&journal->j_state_lock);
923
924 if (!jbd2_has_feature_async_commit(journal)) {
925 err = journal_submit_commit_record(journal, commit_transaction,
926 &cbh, crc32_sum);
927 if (err)
928 jbd2_journal_abort(journal, err);
929 }
930 if (cbh)
931 err = journal_wait_on_commit_record(journal, cbh);
932 stats.run.rs_blocks_logged++;
933 if (jbd2_has_feature_async_commit(journal) &&
934 journal->j_flags & JBD2_BARRIER) {
935 blkdev_issue_flush(journal->j_dev);
936 }
937
938 if (err)
939 jbd2_journal_abort(journal, err);
940
941 WARN_ON_ONCE(
942 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
943
944 /*
945 * Now disk caches for filesystem device are flushed so we are safe to
946 * erase checkpointed transactions from the log by updating journal
947 * superblock.
948 */
949 if (update_tail)
950 jbd2_update_log_tail(journal, first_tid, first_block);
951
952 /* End of a transaction! Finally, we can do checkpoint
953 processing: any buffers committed as a result of this
954 transaction can be removed from any checkpoint list it was on
955 before. */
956
957 jbd_debug(3, "JBD2: commit phase 6\n");
958
959 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
960 J_ASSERT(commit_transaction->t_buffers == NULL);
961 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
962 J_ASSERT(commit_transaction->t_shadow_list == NULL);
963
964restart_loop:
965 /*
966 * As there are other places (journal_unmap_buffer()) adding buffers
967 * to this list we have to be careful and hold the j_list_lock.
968 */
969 spin_lock(&journal->j_list_lock);
970 while (commit_transaction->t_forget) {
971 transaction_t *cp_transaction;
972 struct buffer_head *bh;
973 int try_to_free = 0;
974 bool drop_ref;
975
976 jh = commit_transaction->t_forget;
977 spin_unlock(&journal->j_list_lock);
978 bh = jh2bh(jh);
979 /*
980 * Get a reference so that bh cannot be freed before we are
981 * done with it.
982 */
983 get_bh(bh);
984 spin_lock(&jh->b_state_lock);
985 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
986
987 /*
988 * If there is undo-protected committed data against
989 * this buffer, then we can remove it now. If it is a
990 * buffer needing such protection, the old frozen_data
991 * field now points to a committed version of the
992 * buffer, so rotate that field to the new committed
993 * data.
994 *
995 * Otherwise, we can just throw away the frozen data now.
996 *
997 * We also know that the frozen data has already fired
998 * its triggers if they exist, so we can clear that too.
999 */
1000 if (jh->b_committed_data) {
1001 jbd2_free(jh->b_committed_data, bh->b_size);
1002 jh->b_committed_data = NULL;
1003 if (jh->b_frozen_data) {
1004 jh->b_committed_data = jh->b_frozen_data;
1005 jh->b_frozen_data = NULL;
1006 jh->b_frozen_triggers = NULL;
1007 }
1008 } else if (jh->b_frozen_data) {
1009 jbd2_free(jh->b_frozen_data, bh->b_size);
1010 jh->b_frozen_data = NULL;
1011 jh->b_frozen_triggers = NULL;
1012 }
1013
1014 spin_lock(&journal->j_list_lock);
1015 cp_transaction = jh->b_cp_transaction;
1016 if (cp_transaction) {
1017 JBUFFER_TRACE(jh, "remove from old cp transaction");
1018 cp_transaction->t_chp_stats.cs_dropped++;
1019 __jbd2_journal_remove_checkpoint(jh);
1020 }
1021
1022 /* Only re-checkpoint the buffer_head if it is marked
1023 * dirty. If the buffer was added to the BJ_Forget list
1024 * by jbd2_journal_forget, it may no longer be dirty and
1025 * there's no point in keeping a checkpoint record for
1026 * it. */
1027
1028 /*
1029 * A buffer which has been freed while still being journaled
1030 * by a previous transaction, refile the buffer to BJ_Forget of
1031 * the running transaction. If the just committed transaction
1032 * contains "add to orphan" operation, we can completely
1033 * invalidate the buffer now. We are rather through in that
1034 * since the buffer may be still accessible when blocksize <
1035 * pagesize and it is attached to the last partial page.
1036 */
1037 if (buffer_freed(bh) && !jh->b_next_transaction) {
1038 struct address_space *mapping;
1039
1040 clear_buffer_freed(bh);
1041 clear_buffer_jbddirty(bh);
1042
1043 /*
1044 * Block device buffers need to stay mapped all the
1045 * time, so it is enough to clear buffer_jbddirty and
1046 * buffer_freed bits. For the file mapping buffers (i.e.
1047 * journalled data) we need to unmap buffer and clear
1048 * more bits. We also need to be careful about the check
1049 * because the data page mapping can get cleared under
1050 * our hands. Note that if mapping == NULL, we don't
1051 * need to make buffer unmapped because the page is
1052 * already detached from the mapping and buffers cannot
1053 * get reused.
1054 */
1055 mapping = READ_ONCE(bh->b_page->mapping);
1056 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1057 clear_buffer_mapped(bh);
1058 clear_buffer_new(bh);
1059 clear_buffer_req(bh);
1060 bh->b_bdev = NULL;
1061 }
1062 }
1063
1064 if (buffer_jbddirty(bh)) {
1065 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1066 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1067 if (is_journal_aborted(journal))
1068 clear_buffer_jbddirty(bh);
1069 } else {
1070 J_ASSERT_BH(bh, !buffer_dirty(bh));
1071 /*
1072 * The buffer on BJ_Forget list and not jbddirty means
1073 * it has been freed by this transaction and hence it
1074 * could not have been reallocated until this
1075 * transaction has committed. *BUT* it could be
1076 * reallocated once we have written all the data to
1077 * disk and before we process the buffer on BJ_Forget
1078 * list.
1079 */
1080 if (!jh->b_next_transaction)
1081 try_to_free = 1;
1082 }
1083 JBUFFER_TRACE(jh, "refile or unfile buffer");
1084 drop_ref = __jbd2_journal_refile_buffer(jh);
1085 spin_unlock(&jh->b_state_lock);
1086 if (drop_ref)
1087 jbd2_journal_put_journal_head(jh);
1088 if (try_to_free)
1089 release_buffer_page(bh); /* Drops bh reference */
1090 else
1091 __brelse(bh);
1092 cond_resched_lock(&journal->j_list_lock);
1093 }
1094 spin_unlock(&journal->j_list_lock);
1095 /*
1096 * This is a bit sleazy. We use j_list_lock to protect transition
1097 * of a transaction into T_FINISHED state and calling
1098 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1099 * other checkpointing code processing the transaction...
1100 */
1101 write_lock(&journal->j_state_lock);
1102 spin_lock(&journal->j_list_lock);
1103 /*
1104 * Now recheck if some buffers did not get attached to the transaction
1105 * while the lock was dropped...
1106 */
1107 if (commit_transaction->t_forget) {
1108 spin_unlock(&journal->j_list_lock);
1109 write_unlock(&journal->j_state_lock);
1110 goto restart_loop;
1111 }
1112
1113 /* Add the transaction to the checkpoint list
1114 * __journal_remove_checkpoint() can not destroy transaction
1115 * under us because it is not marked as T_FINISHED yet */
1116 if (journal->j_checkpoint_transactions == NULL) {
1117 journal->j_checkpoint_transactions = commit_transaction;
1118 commit_transaction->t_cpnext = commit_transaction;
1119 commit_transaction->t_cpprev = commit_transaction;
1120 } else {
1121 commit_transaction->t_cpnext =
1122 journal->j_checkpoint_transactions;
1123 commit_transaction->t_cpprev =
1124 commit_transaction->t_cpnext->t_cpprev;
1125 commit_transaction->t_cpnext->t_cpprev =
1126 commit_transaction;
1127 commit_transaction->t_cpprev->t_cpnext =
1128 commit_transaction;
1129 }
1130 spin_unlock(&journal->j_list_lock);
1131
1132 /* Done with this transaction! */
1133
1134 jbd_debug(3, "JBD2: commit phase 7\n");
1135
1136 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1137
1138 commit_transaction->t_start = jiffies;
1139 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1140 commit_transaction->t_start);
1141
1142 /*
1143 * File the transaction statistics
1144 */
1145 stats.ts_tid = commit_transaction->t_tid;
1146 stats.run.rs_handle_count =
1147 atomic_read(&commit_transaction->t_handle_count);
1148 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1149 commit_transaction->t_tid, &stats.run);
1150 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1151
1152 commit_transaction->t_state = T_COMMIT_CALLBACK;
1153 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1154 journal->j_commit_sequence = commit_transaction->t_tid;
1155 journal->j_committing_transaction = NULL;
1156 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1157
1158 /*
1159 * weight the commit time higher than the average time so we don't
1160 * react too strongly to vast changes in the commit time
1161 */
1162 if (likely(journal->j_average_commit_time))
1163 journal->j_average_commit_time = (commit_time +
1164 journal->j_average_commit_time*3) / 4;
1165 else
1166 journal->j_average_commit_time = commit_time;
1167
1168 write_unlock(&journal->j_state_lock);
1169
1170 if (journal->j_commit_callback)
1171 journal->j_commit_callback(journal, commit_transaction);
1172 if (journal->j_fc_cleanup_callback)
1173 journal->j_fc_cleanup_callback(journal, 1);
1174
1175 trace_jbd2_end_commit(journal, commit_transaction);
1176 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1177 journal->j_commit_sequence, journal->j_tail_sequence);
1178
1179 write_lock(&journal->j_state_lock);
1180 journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1181 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1182 spin_lock(&journal->j_list_lock);
1183 commit_transaction->t_state = T_FINISHED;
1184 /* Check if the transaction can be dropped now that we are finished */
1185 if (commit_transaction->t_checkpoint_list == NULL &&
1186 commit_transaction->t_checkpoint_io_list == NULL) {
1187 __jbd2_journal_drop_transaction(journal, commit_transaction);
1188 jbd2_journal_free_transaction(commit_transaction);
1189 }
1190 spin_unlock(&journal->j_list_lock);
1191 write_unlock(&journal->j_state_lock);
1192 wake_up(&journal->j_wait_done_commit);
1193 wake_up(&journal->j_fc_wait);
1194
1195 /*
1196 * Calculate overall stats
1197 */
1198 spin_lock(&journal->j_history_lock);
1199 journal->j_stats.ts_tid++;
1200 journal->j_stats.ts_requested += stats.ts_requested;
1201 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1202 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1203 journal->j_stats.run.rs_running += stats.run.rs_running;
1204 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1205 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1206 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1207 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1208 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1209 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1210 spin_unlock(&journal->j_history_lock);
1211}