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1/*
2 * linux/fs/jbd2/commit.c
3 *
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
5 *
6 * Copyright 1998 Red Hat corp --- All Rights Reserved
7 *
8 * This file is part of the Linux kernel and is made available under
9 * the terms of the GNU General Public License, version 2, or at your
10 * option, any later version, incorporated herein by reference.
11 *
12 * Journal commit routines for the generic filesystem journaling code;
13 * part of the ext2fs journaling system.
14 */
15
16#include <linux/time.h>
17#include <linux/fs.h>
18#include <linux/jbd2.h>
19#include <linux/errno.h>
20#include <linux/slab.h>
21#include <linux/mm.h>
22#include <linux/pagemap.h>
23#include <linux/jiffies.h>
24#include <linux/crc32.h>
25#include <linux/writeback.h>
26#include <linux/backing-dev.h>
27#include <linux/bio.h>
28#include <linux/blkdev.h>
29#include <linux/bitops.h>
30#include <trace/events/jbd2.h>
31
32/*
33 * Default IO end handler for temporary BJ_IO buffer_heads.
34 */
35static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
36{
37 BUFFER_TRACE(bh, "");
38 if (uptodate)
39 set_buffer_uptodate(bh);
40 else
41 clear_buffer_uptodate(bh);
42 unlock_buffer(bh);
43}
44
45/*
46 * When an ext4 file is truncated, it is possible that some pages are not
47 * successfully freed, because they are attached to a committing transaction.
48 * After the transaction commits, these pages are left on the LRU, with no
49 * ->mapping, and with attached buffers. These pages are trivially reclaimable
50 * by the VM, but their apparent absence upsets the VM accounting, and it makes
51 * the numbers in /proc/meminfo look odd.
52 *
53 * So here, we have a buffer which has just come off the forget list. Look to
54 * see if we can strip all buffers from the backing page.
55 *
56 * Called under lock_journal(), and possibly under journal_datalist_lock. The
57 * caller provided us with a ref against the buffer, and we drop that here.
58 */
59static void release_buffer_page(struct buffer_head *bh)
60{
61 struct page *page;
62
63 if (buffer_dirty(bh))
64 goto nope;
65 if (atomic_read(&bh->b_count) != 1)
66 goto nope;
67 page = bh->b_page;
68 if (!page)
69 goto nope;
70 if (page->mapping)
71 goto nope;
72
73 /* OK, it's a truncated page */
74 if (!trylock_page(page))
75 goto nope;
76
77 page_cache_get(page);
78 __brelse(bh);
79 try_to_free_buffers(page);
80 unlock_page(page);
81 page_cache_release(page);
82 return;
83
84nope:
85 __brelse(bh);
86}
87
88static void jbd2_commit_block_csum_set(journal_t *j,
89 struct journal_head *descriptor)
90{
91 struct commit_header *h;
92 __u32 csum;
93
94 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
95 return;
96
97 h = (struct commit_header *)(jh2bh(descriptor)->b_data);
98 h->h_chksum_type = 0;
99 h->h_chksum_size = 0;
100 h->h_chksum[0] = 0;
101 csum = jbd2_chksum(j, j->j_csum_seed, jh2bh(descriptor)->b_data,
102 j->j_blocksize);
103 h->h_chksum[0] = cpu_to_be32(csum);
104}
105
106/*
107 * Done it all: now submit the commit record. We should have
108 * cleaned up our previous buffers by now, so if we are in abort
109 * mode we can now just skip the rest of the journal write
110 * entirely.
111 *
112 * Returns 1 if the journal needs to be aborted or 0 on success
113 */
114static int journal_submit_commit_record(journal_t *journal,
115 transaction_t *commit_transaction,
116 struct buffer_head **cbh,
117 __u32 crc32_sum)
118{
119 struct journal_head *descriptor;
120 struct commit_header *tmp;
121 struct buffer_head *bh;
122 int ret;
123 struct timespec now = current_kernel_time();
124
125 *cbh = NULL;
126
127 if (is_journal_aborted(journal))
128 return 0;
129
130 descriptor = jbd2_journal_get_descriptor_buffer(journal);
131 if (!descriptor)
132 return 1;
133
134 bh = jh2bh(descriptor);
135
136 tmp = (struct commit_header *)bh->b_data;
137 tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
138 tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK);
139 tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
140 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
141 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
142
143 if (JBD2_HAS_COMPAT_FEATURE(journal,
144 JBD2_FEATURE_COMPAT_CHECKSUM)) {
145 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
146 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
147 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
148 }
149 jbd2_commit_block_csum_set(journal, descriptor);
150
151 JBUFFER_TRACE(descriptor, "submit commit block");
152 lock_buffer(bh);
153 clear_buffer_dirty(bh);
154 set_buffer_uptodate(bh);
155 bh->b_end_io = journal_end_buffer_io_sync;
156
157 if (journal->j_flags & JBD2_BARRIER &&
158 !JBD2_HAS_INCOMPAT_FEATURE(journal,
159 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT))
160 ret = submit_bh(WRITE_SYNC | WRITE_FLUSH_FUA, bh);
161 else
162 ret = submit_bh(WRITE_SYNC, bh);
163
164 *cbh = bh;
165 return ret;
166}
167
168/*
169 * This function along with journal_submit_commit_record
170 * allows to write the commit record asynchronously.
171 */
172static int journal_wait_on_commit_record(journal_t *journal,
173 struct buffer_head *bh)
174{
175 int ret = 0;
176
177 clear_buffer_dirty(bh);
178 wait_on_buffer(bh);
179
180 if (unlikely(!buffer_uptodate(bh)))
181 ret = -EIO;
182 put_bh(bh); /* One for getblk() */
183 jbd2_journal_put_journal_head(bh2jh(bh));
184
185 return ret;
186}
187
188/*
189 * write the filemap data using writepage() address_space_operations.
190 * We don't do block allocation here even for delalloc. We don't
191 * use writepages() because with dealyed allocation we may be doing
192 * block allocation in writepages().
193 */
194static int journal_submit_inode_data_buffers(struct address_space *mapping)
195{
196 int ret;
197 struct writeback_control wbc = {
198 .sync_mode = WB_SYNC_ALL,
199 .nr_to_write = mapping->nrpages * 2,
200 .range_start = 0,
201 .range_end = i_size_read(mapping->host),
202 };
203
204 ret = generic_writepages(mapping, &wbc);
205 return ret;
206}
207
208/*
209 * Submit all the data buffers of inode associated with the transaction to
210 * disk.
211 *
212 * We are in a committing transaction. Therefore no new inode can be added to
213 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
214 * operate on from being released while we write out pages.
215 */
216static int journal_submit_data_buffers(journal_t *journal,
217 transaction_t *commit_transaction)
218{
219 struct jbd2_inode *jinode;
220 int err, ret = 0;
221 struct address_space *mapping;
222
223 spin_lock(&journal->j_list_lock);
224 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
225 mapping = jinode->i_vfs_inode->i_mapping;
226 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
227 spin_unlock(&journal->j_list_lock);
228 /*
229 * submit the inode data buffers. We use writepage
230 * instead of writepages. Because writepages can do
231 * block allocation with delalloc. We need to write
232 * only allocated blocks here.
233 */
234 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
235 err = journal_submit_inode_data_buffers(mapping);
236 if (!ret)
237 ret = err;
238 spin_lock(&journal->j_list_lock);
239 J_ASSERT(jinode->i_transaction == commit_transaction);
240 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
241 smp_mb__after_clear_bit();
242 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
243 }
244 spin_unlock(&journal->j_list_lock);
245 return ret;
246}
247
248/*
249 * Wait for data submitted for writeout, refile inodes to proper
250 * transaction if needed.
251 *
252 */
253static int journal_finish_inode_data_buffers(journal_t *journal,
254 transaction_t *commit_transaction)
255{
256 struct jbd2_inode *jinode, *next_i;
257 int err, ret = 0;
258
259 /* For locking, see the comment in journal_submit_data_buffers() */
260 spin_lock(&journal->j_list_lock);
261 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
262 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
263 spin_unlock(&journal->j_list_lock);
264 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
265 if (err) {
266 /*
267 * Because AS_EIO is cleared by
268 * filemap_fdatawait_range(), set it again so
269 * that user process can get -EIO from fsync().
270 */
271 set_bit(AS_EIO,
272 &jinode->i_vfs_inode->i_mapping->flags);
273
274 if (!ret)
275 ret = err;
276 }
277 spin_lock(&journal->j_list_lock);
278 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
279 smp_mb__after_clear_bit();
280 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
281 }
282
283 /* Now refile inode to proper lists */
284 list_for_each_entry_safe(jinode, next_i,
285 &commit_transaction->t_inode_list, i_list) {
286 list_del(&jinode->i_list);
287 if (jinode->i_next_transaction) {
288 jinode->i_transaction = jinode->i_next_transaction;
289 jinode->i_next_transaction = NULL;
290 list_add(&jinode->i_list,
291 &jinode->i_transaction->t_inode_list);
292 } else {
293 jinode->i_transaction = NULL;
294 }
295 }
296 spin_unlock(&journal->j_list_lock);
297
298 return ret;
299}
300
301static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
302{
303 struct page *page = bh->b_page;
304 char *addr;
305 __u32 checksum;
306
307 addr = kmap_atomic(page);
308 checksum = crc32_be(crc32_sum,
309 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
310 kunmap_atomic(addr);
311
312 return checksum;
313}
314
315static void write_tag_block(int tag_bytes, journal_block_tag_t *tag,
316 unsigned long long block)
317{
318 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
319 if (tag_bytes > JBD2_TAG_SIZE32)
320 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
321}
322
323static void jbd2_descr_block_csum_set(journal_t *j,
324 struct journal_head *descriptor)
325{
326 struct jbd2_journal_block_tail *tail;
327 __u32 csum;
328
329 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
330 return;
331
332 tail = (struct jbd2_journal_block_tail *)
333 (jh2bh(descriptor)->b_data + j->j_blocksize -
334 sizeof(struct jbd2_journal_block_tail));
335 tail->t_checksum = 0;
336 csum = jbd2_chksum(j, j->j_csum_seed, jh2bh(descriptor)->b_data,
337 j->j_blocksize);
338 tail->t_checksum = cpu_to_be32(csum);
339}
340
341static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
342 struct buffer_head *bh, __u32 sequence)
343{
344 struct page *page = bh->b_page;
345 __u8 *addr;
346 __u32 csum;
347
348 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
349 return;
350
351 sequence = cpu_to_be32(sequence);
352 addr = kmap_atomic(page, KM_USER0);
353 csum = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&sequence,
354 sizeof(sequence));
355 csum = jbd2_chksum(j, csum, addr + offset_in_page(bh->b_data),
356 bh->b_size);
357 kunmap_atomic(addr, KM_USER0);
358
359 tag->t_checksum = cpu_to_be32(csum);
360}
361/*
362 * jbd2_journal_commit_transaction
363 *
364 * The primary function for committing a transaction to the log. This
365 * function is called by the journal thread to begin a complete commit.
366 */
367void jbd2_journal_commit_transaction(journal_t *journal)
368{
369 struct transaction_stats_s stats;
370 transaction_t *commit_transaction;
371 struct journal_head *jh, *new_jh, *descriptor;
372 struct buffer_head **wbuf = journal->j_wbuf;
373 int bufs;
374 int flags;
375 int err;
376 unsigned long long blocknr;
377 ktime_t start_time;
378 u64 commit_time;
379 char *tagp = NULL;
380 journal_header_t *header;
381 journal_block_tag_t *tag = NULL;
382 int space_left = 0;
383 int first_tag = 0;
384 int tag_flag;
385 int i, to_free = 0;
386 int tag_bytes = journal_tag_bytes(journal);
387 struct buffer_head *cbh = NULL; /* For transactional checksums */
388 __u32 crc32_sum = ~0;
389 struct blk_plug plug;
390 /* Tail of the journal */
391 unsigned long first_block;
392 tid_t first_tid;
393 int update_tail;
394 int csum_size = 0;
395
396 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
397 csum_size = sizeof(struct jbd2_journal_block_tail);
398
399 /*
400 * First job: lock down the current transaction and wait for
401 * all outstanding updates to complete.
402 */
403
404 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
405 if (journal->j_flags & JBD2_FLUSHED) {
406 jbd_debug(3, "super block updated\n");
407 mutex_lock(&journal->j_checkpoint_mutex);
408 /*
409 * We hold j_checkpoint_mutex so tail cannot change under us.
410 * We don't need any special data guarantees for writing sb
411 * since journal is empty and it is ok for write to be
412 * flushed only with transaction commit.
413 */
414 jbd2_journal_update_sb_log_tail(journal,
415 journal->j_tail_sequence,
416 journal->j_tail,
417 WRITE_SYNC);
418 mutex_unlock(&journal->j_checkpoint_mutex);
419 } else {
420 jbd_debug(3, "superblock not updated\n");
421 }
422
423 J_ASSERT(journal->j_running_transaction != NULL);
424 J_ASSERT(journal->j_committing_transaction == NULL);
425
426 commit_transaction = journal->j_running_transaction;
427 J_ASSERT(commit_transaction->t_state == T_RUNNING);
428
429 trace_jbd2_start_commit(journal, commit_transaction);
430 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
431 commit_transaction->t_tid);
432
433 write_lock(&journal->j_state_lock);
434 commit_transaction->t_state = T_LOCKED;
435
436 trace_jbd2_commit_locking(journal, commit_transaction);
437 stats.run.rs_wait = commit_transaction->t_max_wait;
438 stats.run.rs_locked = jiffies;
439 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
440 stats.run.rs_locked);
441
442 spin_lock(&commit_transaction->t_handle_lock);
443 while (atomic_read(&commit_transaction->t_updates)) {
444 DEFINE_WAIT(wait);
445
446 prepare_to_wait(&journal->j_wait_updates, &wait,
447 TASK_UNINTERRUPTIBLE);
448 if (atomic_read(&commit_transaction->t_updates)) {
449 spin_unlock(&commit_transaction->t_handle_lock);
450 write_unlock(&journal->j_state_lock);
451 schedule();
452 write_lock(&journal->j_state_lock);
453 spin_lock(&commit_transaction->t_handle_lock);
454 }
455 finish_wait(&journal->j_wait_updates, &wait);
456 }
457 spin_unlock(&commit_transaction->t_handle_lock);
458
459 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
460 journal->j_max_transaction_buffers);
461
462 /*
463 * First thing we are allowed to do is to discard any remaining
464 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
465 * that there are no such buffers: if a large filesystem
466 * operation like a truncate needs to split itself over multiple
467 * transactions, then it may try to do a jbd2_journal_restart() while
468 * there are still BJ_Reserved buffers outstanding. These must
469 * be released cleanly from the current transaction.
470 *
471 * In this case, the filesystem must still reserve write access
472 * again before modifying the buffer in the new transaction, but
473 * we do not require it to remember exactly which old buffers it
474 * has reserved. This is consistent with the existing behaviour
475 * that multiple jbd2_journal_get_write_access() calls to the same
476 * buffer are perfectly permissible.
477 */
478 while (commit_transaction->t_reserved_list) {
479 jh = commit_transaction->t_reserved_list;
480 JBUFFER_TRACE(jh, "reserved, unused: refile");
481 /*
482 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
483 * leave undo-committed data.
484 */
485 if (jh->b_committed_data) {
486 struct buffer_head *bh = jh2bh(jh);
487
488 jbd_lock_bh_state(bh);
489 jbd2_free(jh->b_committed_data, bh->b_size);
490 jh->b_committed_data = NULL;
491 jbd_unlock_bh_state(bh);
492 }
493 jbd2_journal_refile_buffer(journal, jh);
494 }
495
496 /*
497 * Now try to drop any written-back buffers from the journal's
498 * checkpoint lists. We do this *before* commit because it potentially
499 * frees some memory
500 */
501 spin_lock(&journal->j_list_lock);
502 __jbd2_journal_clean_checkpoint_list(journal);
503 spin_unlock(&journal->j_list_lock);
504
505 jbd_debug(3, "JBD2: commit phase 1\n");
506
507 /*
508 * Clear revoked flag to reflect there is no revoked buffers
509 * in the next transaction which is going to be started.
510 */
511 jbd2_clear_buffer_revoked_flags(journal);
512
513 /*
514 * Switch to a new revoke table.
515 */
516 jbd2_journal_switch_revoke_table(journal);
517
518 trace_jbd2_commit_flushing(journal, commit_transaction);
519 stats.run.rs_flushing = jiffies;
520 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
521 stats.run.rs_flushing);
522
523 commit_transaction->t_state = T_FLUSH;
524 journal->j_committing_transaction = commit_transaction;
525 journal->j_running_transaction = NULL;
526 start_time = ktime_get();
527 commit_transaction->t_log_start = journal->j_head;
528 wake_up(&journal->j_wait_transaction_locked);
529 write_unlock(&journal->j_state_lock);
530
531 jbd_debug(3, "JBD2: commit phase 2\n");
532
533 /*
534 * Now start flushing things to disk, in the order they appear
535 * on the transaction lists. Data blocks go first.
536 */
537 err = journal_submit_data_buffers(journal, commit_transaction);
538 if (err)
539 jbd2_journal_abort(journal, err);
540
541 blk_start_plug(&plug);
542 jbd2_journal_write_revoke_records(journal, commit_transaction,
543 WRITE_SYNC);
544 blk_finish_plug(&plug);
545
546 jbd_debug(3, "JBD2: commit phase 2\n");
547
548 /*
549 * Way to go: we have now written out all of the data for a
550 * transaction! Now comes the tricky part: we need to write out
551 * metadata. Loop over the transaction's entire buffer list:
552 */
553 write_lock(&journal->j_state_lock);
554 commit_transaction->t_state = T_COMMIT;
555 write_unlock(&journal->j_state_lock);
556
557 trace_jbd2_commit_logging(journal, commit_transaction);
558 stats.run.rs_logging = jiffies;
559 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
560 stats.run.rs_logging);
561 stats.run.rs_blocks =
562 atomic_read(&commit_transaction->t_outstanding_credits);
563 stats.run.rs_blocks_logged = 0;
564
565 J_ASSERT(commit_transaction->t_nr_buffers <=
566 atomic_read(&commit_transaction->t_outstanding_credits));
567
568 err = 0;
569 descriptor = NULL;
570 bufs = 0;
571 blk_start_plug(&plug);
572 while (commit_transaction->t_buffers) {
573
574 /* Find the next buffer to be journaled... */
575
576 jh = commit_transaction->t_buffers;
577
578 /* If we're in abort mode, we just un-journal the buffer and
579 release it. */
580
581 if (is_journal_aborted(journal)) {
582 clear_buffer_jbddirty(jh2bh(jh));
583 JBUFFER_TRACE(jh, "journal is aborting: refile");
584 jbd2_buffer_abort_trigger(jh,
585 jh->b_frozen_data ?
586 jh->b_frozen_triggers :
587 jh->b_triggers);
588 jbd2_journal_refile_buffer(journal, jh);
589 /* If that was the last one, we need to clean up
590 * any descriptor buffers which may have been
591 * already allocated, even if we are now
592 * aborting. */
593 if (!commit_transaction->t_buffers)
594 goto start_journal_io;
595 continue;
596 }
597
598 /* Make sure we have a descriptor block in which to
599 record the metadata buffer. */
600
601 if (!descriptor) {
602 struct buffer_head *bh;
603
604 J_ASSERT (bufs == 0);
605
606 jbd_debug(4, "JBD2: get descriptor\n");
607
608 descriptor = jbd2_journal_get_descriptor_buffer(journal);
609 if (!descriptor) {
610 jbd2_journal_abort(journal, -EIO);
611 continue;
612 }
613
614 bh = jh2bh(descriptor);
615 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
616 (unsigned long long)bh->b_blocknr, bh->b_data);
617 header = (journal_header_t *)&bh->b_data[0];
618 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
619 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK);
620 header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
621
622 tagp = &bh->b_data[sizeof(journal_header_t)];
623 space_left = bh->b_size - sizeof(journal_header_t);
624 first_tag = 1;
625 set_buffer_jwrite(bh);
626 set_buffer_dirty(bh);
627 wbuf[bufs++] = bh;
628
629 /* Record it so that we can wait for IO
630 completion later */
631 BUFFER_TRACE(bh, "ph3: file as descriptor");
632 jbd2_journal_file_buffer(descriptor, commit_transaction,
633 BJ_LogCtl);
634 }
635
636 /* Where is the buffer to be written? */
637
638 err = jbd2_journal_next_log_block(journal, &blocknr);
639 /* If the block mapping failed, just abandon the buffer
640 and repeat this loop: we'll fall into the
641 refile-on-abort condition above. */
642 if (err) {
643 jbd2_journal_abort(journal, err);
644 continue;
645 }
646
647 /*
648 * start_this_handle() uses t_outstanding_credits to determine
649 * the free space in the log, but this counter is changed
650 * by jbd2_journal_next_log_block() also.
651 */
652 atomic_dec(&commit_transaction->t_outstanding_credits);
653
654 /* Bump b_count to prevent truncate from stumbling over
655 the shadowed buffer! @@@ This can go if we ever get
656 rid of the BJ_IO/BJ_Shadow pairing of buffers. */
657 atomic_inc(&jh2bh(jh)->b_count);
658
659 /* Make a temporary IO buffer with which to write it out
660 (this will requeue both the metadata buffer and the
661 temporary IO buffer). new_bh goes on BJ_IO*/
662
663 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
664 /*
665 * akpm: jbd2_journal_write_metadata_buffer() sets
666 * new_bh->b_transaction to commit_transaction.
667 * We need to clean this up before we release new_bh
668 * (which is of type BJ_IO)
669 */
670 JBUFFER_TRACE(jh, "ph3: write metadata");
671 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
672 jh, &new_jh, blocknr);
673 if (flags < 0) {
674 jbd2_journal_abort(journal, flags);
675 continue;
676 }
677 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state);
678 wbuf[bufs++] = jh2bh(new_jh);
679
680 /* Record the new block's tag in the current descriptor
681 buffer */
682
683 tag_flag = 0;
684 if (flags & 1)
685 tag_flag |= JBD2_FLAG_ESCAPE;
686 if (!first_tag)
687 tag_flag |= JBD2_FLAG_SAME_UUID;
688
689 tag = (journal_block_tag_t *) tagp;
690 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr);
691 tag->t_flags = cpu_to_be16(tag_flag);
692 jbd2_block_tag_csum_set(journal, tag, jh2bh(new_jh),
693 commit_transaction->t_tid);
694 tagp += tag_bytes;
695 space_left -= tag_bytes;
696
697 if (first_tag) {
698 memcpy (tagp, journal->j_uuid, 16);
699 tagp += 16;
700 space_left -= 16;
701 first_tag = 0;
702 }
703
704 /* If there's no more to do, or if the descriptor is full,
705 let the IO rip! */
706
707 if (bufs == journal->j_wbufsize ||
708 commit_transaction->t_buffers == NULL ||
709 space_left < tag_bytes + 16 + csum_size) {
710
711 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
712
713 /* Write an end-of-descriptor marker before
714 submitting the IOs. "tag" still points to
715 the last tag we set up. */
716
717 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
718
719 jbd2_descr_block_csum_set(journal, descriptor);
720start_journal_io:
721 for (i = 0; i < bufs; i++) {
722 struct buffer_head *bh = wbuf[i];
723 /*
724 * Compute checksum.
725 */
726 if (JBD2_HAS_COMPAT_FEATURE(journal,
727 JBD2_FEATURE_COMPAT_CHECKSUM)) {
728 crc32_sum =
729 jbd2_checksum_data(crc32_sum, bh);
730 }
731
732 lock_buffer(bh);
733 clear_buffer_dirty(bh);
734 set_buffer_uptodate(bh);
735 bh->b_end_io = journal_end_buffer_io_sync;
736 submit_bh(WRITE_SYNC, bh);
737 }
738 cond_resched();
739 stats.run.rs_blocks_logged += bufs;
740
741 /* Force a new descriptor to be generated next
742 time round the loop. */
743 descriptor = NULL;
744 bufs = 0;
745 }
746 }
747
748 err = journal_finish_inode_data_buffers(journal, commit_transaction);
749 if (err) {
750 printk(KERN_WARNING
751 "JBD2: Detected IO errors while flushing file data "
752 "on %s\n", journal->j_devname);
753 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
754 jbd2_journal_abort(journal, err);
755 err = 0;
756 }
757
758 /*
759 * Get current oldest transaction in the log before we issue flush
760 * to the filesystem device. After the flush we can be sure that
761 * blocks of all older transactions are checkpointed to persistent
762 * storage and we will be safe to update journal start in the
763 * superblock with the numbers we get here.
764 */
765 update_tail =
766 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
767
768 write_lock(&journal->j_state_lock);
769 if (update_tail) {
770 long freed = first_block - journal->j_tail;
771
772 if (first_block < journal->j_tail)
773 freed += journal->j_last - journal->j_first;
774 /* Update tail only if we free significant amount of space */
775 if (freed < journal->j_maxlen / 4)
776 update_tail = 0;
777 }
778 J_ASSERT(commit_transaction->t_state == T_COMMIT);
779 commit_transaction->t_state = T_COMMIT_DFLUSH;
780 write_unlock(&journal->j_state_lock);
781
782 /*
783 * If the journal is not located on the file system device,
784 * then we must flush the file system device before we issue
785 * the commit record
786 */
787 if (commit_transaction->t_need_data_flush &&
788 (journal->j_fs_dev != journal->j_dev) &&
789 (journal->j_flags & JBD2_BARRIER))
790 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
791
792 /* Done it all: now write the commit record asynchronously. */
793 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
794 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
795 err = journal_submit_commit_record(journal, commit_transaction,
796 &cbh, crc32_sum);
797 if (err)
798 __jbd2_journal_abort_hard(journal);
799 }
800
801 blk_finish_plug(&plug);
802
803 /* Lo and behold: we have just managed to send a transaction to
804 the log. Before we can commit it, wait for the IO so far to
805 complete. Control buffers being written are on the
806 transaction's t_log_list queue, and metadata buffers are on
807 the t_iobuf_list queue.
808
809 Wait for the buffers in reverse order. That way we are
810 less likely to be woken up until all IOs have completed, and
811 so we incur less scheduling load.
812 */
813
814 jbd_debug(3, "JBD2: commit phase 3\n");
815
816 /*
817 * akpm: these are BJ_IO, and j_list_lock is not needed.
818 * See __journal_try_to_free_buffer.
819 */
820wait_for_iobuf:
821 while (commit_transaction->t_iobuf_list != NULL) {
822 struct buffer_head *bh;
823
824 jh = commit_transaction->t_iobuf_list->b_tprev;
825 bh = jh2bh(jh);
826 if (buffer_locked(bh)) {
827 wait_on_buffer(bh);
828 goto wait_for_iobuf;
829 }
830 if (cond_resched())
831 goto wait_for_iobuf;
832
833 if (unlikely(!buffer_uptodate(bh)))
834 err = -EIO;
835
836 clear_buffer_jwrite(bh);
837
838 JBUFFER_TRACE(jh, "ph4: unfile after journal write");
839 jbd2_journal_unfile_buffer(journal, jh);
840
841 /*
842 * ->t_iobuf_list should contain only dummy buffer_heads
843 * which were created by jbd2_journal_write_metadata_buffer().
844 */
845 BUFFER_TRACE(bh, "dumping temporary bh");
846 jbd2_journal_put_journal_head(jh);
847 __brelse(bh);
848 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
849 free_buffer_head(bh);
850
851 /* We also have to unlock and free the corresponding
852 shadowed buffer */
853 jh = commit_transaction->t_shadow_list->b_tprev;
854 bh = jh2bh(jh);
855 clear_bit(BH_JWrite, &bh->b_state);
856 J_ASSERT_BH(bh, buffer_jbddirty(bh));
857
858 /* The metadata is now released for reuse, but we need
859 to remember it against this transaction so that when
860 we finally commit, we can do any checkpointing
861 required. */
862 JBUFFER_TRACE(jh, "file as BJ_Forget");
863 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
864 /*
865 * Wake up any transactions which were waiting for this IO to
866 * complete. The barrier must be here so that changes by
867 * jbd2_journal_file_buffer() take effect before wake_up_bit()
868 * does the waitqueue check.
869 */
870 smp_mb();
871 wake_up_bit(&bh->b_state, BH_Unshadow);
872 JBUFFER_TRACE(jh, "brelse shadowed buffer");
873 __brelse(bh);
874 }
875
876 J_ASSERT (commit_transaction->t_shadow_list == NULL);
877
878 jbd_debug(3, "JBD2: commit phase 4\n");
879
880 /* Here we wait for the revoke record and descriptor record buffers */
881 wait_for_ctlbuf:
882 while (commit_transaction->t_log_list != NULL) {
883 struct buffer_head *bh;
884
885 jh = commit_transaction->t_log_list->b_tprev;
886 bh = jh2bh(jh);
887 if (buffer_locked(bh)) {
888 wait_on_buffer(bh);
889 goto wait_for_ctlbuf;
890 }
891 if (cond_resched())
892 goto wait_for_ctlbuf;
893
894 if (unlikely(!buffer_uptodate(bh)))
895 err = -EIO;
896
897 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
898 clear_buffer_jwrite(bh);
899 jbd2_journal_unfile_buffer(journal, jh);
900 jbd2_journal_put_journal_head(jh);
901 __brelse(bh); /* One for getblk */
902 /* AKPM: bforget here */
903 }
904
905 if (err)
906 jbd2_journal_abort(journal, err);
907
908 jbd_debug(3, "JBD2: commit phase 5\n");
909 write_lock(&journal->j_state_lock);
910 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
911 commit_transaction->t_state = T_COMMIT_JFLUSH;
912 write_unlock(&journal->j_state_lock);
913
914 if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
915 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
916 err = journal_submit_commit_record(journal, commit_transaction,
917 &cbh, crc32_sum);
918 if (err)
919 __jbd2_journal_abort_hard(journal);
920 }
921 if (cbh)
922 err = journal_wait_on_commit_record(journal, cbh);
923 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
924 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) &&
925 journal->j_flags & JBD2_BARRIER) {
926 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
927 }
928
929 if (err)
930 jbd2_journal_abort(journal, err);
931
932 /*
933 * Now disk caches for filesystem device are flushed so we are safe to
934 * erase checkpointed transactions from the log by updating journal
935 * superblock.
936 */
937 if (update_tail)
938 jbd2_update_log_tail(journal, first_tid, first_block);
939
940 /* End of a transaction! Finally, we can do checkpoint
941 processing: any buffers committed as a result of this
942 transaction can be removed from any checkpoint list it was on
943 before. */
944
945 jbd_debug(3, "JBD2: commit phase 6\n");
946
947 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
948 J_ASSERT(commit_transaction->t_buffers == NULL);
949 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
950 J_ASSERT(commit_transaction->t_iobuf_list == NULL);
951 J_ASSERT(commit_transaction->t_shadow_list == NULL);
952 J_ASSERT(commit_transaction->t_log_list == NULL);
953
954restart_loop:
955 /*
956 * As there are other places (journal_unmap_buffer()) adding buffers
957 * to this list we have to be careful and hold the j_list_lock.
958 */
959 spin_lock(&journal->j_list_lock);
960 while (commit_transaction->t_forget) {
961 transaction_t *cp_transaction;
962 struct buffer_head *bh;
963 int try_to_free = 0;
964
965 jh = commit_transaction->t_forget;
966 spin_unlock(&journal->j_list_lock);
967 bh = jh2bh(jh);
968 /*
969 * Get a reference so that bh cannot be freed before we are
970 * done with it.
971 */
972 get_bh(bh);
973 jbd_lock_bh_state(bh);
974 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
975
976 /*
977 * If there is undo-protected committed data against
978 * this buffer, then we can remove it now. If it is a
979 * buffer needing such protection, the old frozen_data
980 * field now points to a committed version of the
981 * buffer, so rotate that field to the new committed
982 * data.
983 *
984 * Otherwise, we can just throw away the frozen data now.
985 *
986 * We also know that the frozen data has already fired
987 * its triggers if they exist, so we can clear that too.
988 */
989 if (jh->b_committed_data) {
990 jbd2_free(jh->b_committed_data, bh->b_size);
991 jh->b_committed_data = NULL;
992 if (jh->b_frozen_data) {
993 jh->b_committed_data = jh->b_frozen_data;
994 jh->b_frozen_data = NULL;
995 jh->b_frozen_triggers = NULL;
996 }
997 } else if (jh->b_frozen_data) {
998 jbd2_free(jh->b_frozen_data, bh->b_size);
999 jh->b_frozen_data = NULL;
1000 jh->b_frozen_triggers = NULL;
1001 }
1002
1003 spin_lock(&journal->j_list_lock);
1004 cp_transaction = jh->b_cp_transaction;
1005 if (cp_transaction) {
1006 JBUFFER_TRACE(jh, "remove from old cp transaction");
1007 cp_transaction->t_chp_stats.cs_dropped++;
1008 __jbd2_journal_remove_checkpoint(jh);
1009 }
1010
1011 /* Only re-checkpoint the buffer_head if it is marked
1012 * dirty. If the buffer was added to the BJ_Forget list
1013 * by jbd2_journal_forget, it may no longer be dirty and
1014 * there's no point in keeping a checkpoint record for
1015 * it. */
1016
1017 /* A buffer which has been freed while still being
1018 * journaled by a previous transaction may end up still
1019 * being dirty here, but we want to avoid writing back
1020 * that buffer in the future after the "add to orphan"
1021 * operation been committed, That's not only a performance
1022 * gain, it also stops aliasing problems if the buffer is
1023 * left behind for writeback and gets reallocated for another
1024 * use in a different page. */
1025 if (buffer_freed(bh) && !jh->b_next_transaction) {
1026 clear_buffer_freed(bh);
1027 clear_buffer_jbddirty(bh);
1028 }
1029
1030 if (buffer_jbddirty(bh)) {
1031 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1032 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1033 if (is_journal_aborted(journal))
1034 clear_buffer_jbddirty(bh);
1035 } else {
1036 J_ASSERT_BH(bh, !buffer_dirty(bh));
1037 /*
1038 * The buffer on BJ_Forget list and not jbddirty means
1039 * it has been freed by this transaction and hence it
1040 * could not have been reallocated until this
1041 * transaction has committed. *BUT* it could be
1042 * reallocated once we have written all the data to
1043 * disk and before we process the buffer on BJ_Forget
1044 * list.
1045 */
1046 if (!jh->b_next_transaction)
1047 try_to_free = 1;
1048 }
1049 JBUFFER_TRACE(jh, "refile or unfile buffer");
1050 __jbd2_journal_refile_buffer(jh);
1051 jbd_unlock_bh_state(bh);
1052 if (try_to_free)
1053 release_buffer_page(bh); /* Drops bh reference */
1054 else
1055 __brelse(bh);
1056 cond_resched_lock(&journal->j_list_lock);
1057 }
1058 spin_unlock(&journal->j_list_lock);
1059 /*
1060 * This is a bit sleazy. We use j_list_lock to protect transition
1061 * of a transaction into T_FINISHED state and calling
1062 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1063 * other checkpointing code processing the transaction...
1064 */
1065 write_lock(&journal->j_state_lock);
1066 spin_lock(&journal->j_list_lock);
1067 /*
1068 * Now recheck if some buffers did not get attached to the transaction
1069 * while the lock was dropped...
1070 */
1071 if (commit_transaction->t_forget) {
1072 spin_unlock(&journal->j_list_lock);
1073 write_unlock(&journal->j_state_lock);
1074 goto restart_loop;
1075 }
1076
1077 /* Done with this transaction! */
1078
1079 jbd_debug(3, "JBD2: commit phase 7\n");
1080
1081 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1082
1083 commit_transaction->t_start = jiffies;
1084 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1085 commit_transaction->t_start);
1086
1087 /*
1088 * File the transaction statistics
1089 */
1090 stats.ts_tid = commit_transaction->t_tid;
1091 stats.run.rs_handle_count =
1092 atomic_read(&commit_transaction->t_handle_count);
1093 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1094 commit_transaction->t_tid, &stats.run);
1095
1096 /*
1097 * Calculate overall stats
1098 */
1099 spin_lock(&journal->j_history_lock);
1100 journal->j_stats.ts_tid++;
1101 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1102 journal->j_stats.run.rs_running += stats.run.rs_running;
1103 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1104 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1105 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1106 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1107 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1108 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1109 spin_unlock(&journal->j_history_lock);
1110
1111 commit_transaction->t_state = T_FINISHED;
1112 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1113 journal->j_commit_sequence = commit_transaction->t_tid;
1114 journal->j_committing_transaction = NULL;
1115 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1116
1117 /*
1118 * weight the commit time higher than the average time so we don't
1119 * react too strongly to vast changes in the commit time
1120 */
1121 if (likely(journal->j_average_commit_time))
1122 journal->j_average_commit_time = (commit_time +
1123 journal->j_average_commit_time*3) / 4;
1124 else
1125 journal->j_average_commit_time = commit_time;
1126 write_unlock(&journal->j_state_lock);
1127
1128 if (commit_transaction->t_checkpoint_list == NULL &&
1129 commit_transaction->t_checkpoint_io_list == NULL) {
1130 __jbd2_journal_drop_transaction(journal, commit_transaction);
1131 to_free = 1;
1132 } else {
1133 if (journal->j_checkpoint_transactions == NULL) {
1134 journal->j_checkpoint_transactions = commit_transaction;
1135 commit_transaction->t_cpnext = commit_transaction;
1136 commit_transaction->t_cpprev = commit_transaction;
1137 } else {
1138 commit_transaction->t_cpnext =
1139 journal->j_checkpoint_transactions;
1140 commit_transaction->t_cpprev =
1141 commit_transaction->t_cpnext->t_cpprev;
1142 commit_transaction->t_cpnext->t_cpprev =
1143 commit_transaction;
1144 commit_transaction->t_cpprev->t_cpnext =
1145 commit_transaction;
1146 }
1147 }
1148 spin_unlock(&journal->j_list_lock);
1149
1150 if (journal->j_commit_callback)
1151 journal->j_commit_callback(journal, commit_transaction);
1152
1153 trace_jbd2_end_commit(journal, commit_transaction);
1154 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1155 journal->j_commit_sequence, journal->j_tail_sequence);
1156 if (to_free)
1157 jbd2_journal_free_transaction(commit_transaction);
1158
1159 wake_up(&journal->j_wait_done_commit);
1160}
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
67 if (buffer_dirty(bh))
68 goto nope;
69 if (atomic_read(&bh->b_count) != 1)
70 goto nope;
71 folio = bh->b_folio;
72 if (folio->mapping)
73 goto nope;
74
75 /* OK, it's a truncated page */
76 if (!folio_trylock(folio))
77 goto nope;
78
79 folio_get(folio);
80 __brelse(bh);
81 try_to_free_buffers(folio);
82 folio_unlock(folio);
83 folio_put(folio);
84 return;
85
86nope:
87 __brelse(bh);
88}
89
90static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
91{
92 struct commit_header *h;
93 __u32 csum;
94
95 if (!jbd2_journal_has_csum_v2or3(j))
96 return;
97
98 h = (struct commit_header *)(bh->b_data);
99 h->h_chksum_type = 0;
100 h->h_chksum_size = 0;
101 h->h_chksum[0] = 0;
102 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
103 h->h_chksum[0] = cpu_to_be32(csum);
104}
105
106/*
107 * Done it all: now submit the commit record. We should have
108 * cleaned up our previous buffers by now, so if we are in abort
109 * mode we can now just skip the rest of the journal write
110 * entirely.
111 *
112 * Returns 1 if the journal needs to be aborted or 0 on success
113 */
114static int journal_submit_commit_record(journal_t *journal,
115 transaction_t *commit_transaction,
116 struct buffer_head **cbh,
117 __u32 crc32_sum)
118{
119 struct commit_header *tmp;
120 struct buffer_head *bh;
121 struct timespec64 now;
122 blk_opf_t write_flags = REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS;
123
124 *cbh = NULL;
125
126 if (is_journal_aborted(journal))
127 return 0;
128
129 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
130 JBD2_COMMIT_BLOCK);
131 if (!bh)
132 return 1;
133
134 tmp = (struct commit_header *)bh->b_data;
135 ktime_get_coarse_real_ts64(&now);
136 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
137 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
138
139 if (jbd2_has_feature_checksum(journal)) {
140 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
141 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
142 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
143 }
144 jbd2_commit_block_csum_set(journal, bh);
145
146 BUFFER_TRACE(bh, "submit commit block");
147 lock_buffer(bh);
148 clear_buffer_dirty(bh);
149 set_buffer_uptodate(bh);
150 bh->b_end_io = journal_end_buffer_io_sync;
151
152 if (journal->j_flags & JBD2_BARRIER &&
153 !jbd2_has_feature_async_commit(journal))
154 write_flags |= REQ_PREFLUSH | REQ_FUA;
155
156 submit_bh(write_flags, bh);
157 *cbh = bh;
158 return 0;
159}
160
161/*
162 * This function along with journal_submit_commit_record
163 * allows to write the commit record asynchronously.
164 */
165static int journal_wait_on_commit_record(journal_t *journal,
166 struct buffer_head *bh)
167{
168 int ret = 0;
169
170 clear_buffer_dirty(bh);
171 wait_on_buffer(bh);
172
173 if (unlikely(!buffer_uptodate(bh)))
174 ret = -EIO;
175 put_bh(bh); /* One for getblk() */
176
177 return ret;
178}
179
180/* Send all the data buffers related to an inode */
181int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode)
182{
183 if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
184 return 0;
185
186 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
187 return journal->j_submit_inode_data_buffers(jinode);
188
189}
190EXPORT_SYMBOL(jbd2_submit_inode_data);
191
192int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
193{
194 if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
195 !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
196 return 0;
197 return filemap_fdatawait_range_keep_errors(
198 jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
199 jinode->i_dirty_end);
200}
201EXPORT_SYMBOL(jbd2_wait_inode_data);
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
217 spin_lock(&journal->j_list_lock);
218 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
219 if (!(jinode->i_flags & JI_WRITE_DATA))
220 continue;
221 jinode->i_flags |= JI_COMMIT_RUNNING;
222 spin_unlock(&journal->j_list_lock);
223 /* submit the inode data buffers. */
224 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
225 if (journal->j_submit_inode_data_buffers) {
226 err = journal->j_submit_inode_data_buffers(jinode);
227 if (!ret)
228 ret = err;
229 }
230 spin_lock(&journal->j_list_lock);
231 J_ASSERT(jinode->i_transaction == commit_transaction);
232 jinode->i_flags &= ~JI_COMMIT_RUNNING;
233 smp_mb();
234 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
235 }
236 spin_unlock(&journal->j_list_lock);
237 return ret;
238}
239
240int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
241{
242 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
243
244 return filemap_fdatawait_range_keep_errors(mapping,
245 jinode->i_dirty_start,
246 jinode->i_dirty_end);
247}
248
249/*
250 * Wait for data submitted for writeout, refile inodes to proper
251 * transaction if needed.
252 *
253 */
254static int journal_finish_inode_data_buffers(journal_t *journal,
255 transaction_t *commit_transaction)
256{
257 struct jbd2_inode *jinode, *next_i;
258 int err, ret = 0;
259
260 /* For locking, see the comment in journal_submit_data_buffers() */
261 spin_lock(&journal->j_list_lock);
262 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
263 if (!(jinode->i_flags & JI_WAIT_DATA))
264 continue;
265 jinode->i_flags |= JI_COMMIT_RUNNING;
266 spin_unlock(&journal->j_list_lock);
267 /* wait for the inode data buffers writeout. */
268 if (journal->j_finish_inode_data_buffers) {
269 err = journal->j_finish_inode_data_buffers(jinode);
270 if (!ret)
271 ret = err;
272 }
273 cond_resched();
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 jinode->i_dirty_start = 0;
292 jinode->i_dirty_end = 0;
293 }
294 }
295 spin_unlock(&journal->j_list_lock);
296
297 return ret;
298}
299
300static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
301{
302 char *addr;
303 __u32 checksum;
304
305 addr = kmap_local_folio(bh->b_folio, bh_offset(bh));
306 checksum = crc32_be(crc32_sum, addr, bh->b_size);
307 kunmap_local(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 __u8 *addr;
325 __u32 csum32;
326 __be32 seq;
327
328 if (!jbd2_journal_has_csum_v2or3(j))
329 return;
330
331 seq = cpu_to_be32(sequence);
332 addr = kmap_local_folio(bh->b_folio, bh_offset(bh));
333 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
334 csum32 = jbd2_chksum(j, csum32, addr, bh->b_size);
335 kunmap_local(addr);
336
337 if (jbd2_has_feature_csum3(j))
338 tag3->t_checksum = cpu_to_be32(csum32);
339 else
340 tag->t_checksum = cpu_to_be16(csum32);
341}
342/*
343 * jbd2_journal_commit_transaction
344 *
345 * The primary function for committing a transaction to the log. This
346 * function is called by the journal thread to begin a complete commit.
347 */
348void jbd2_journal_commit_transaction(journal_t *journal)
349{
350 struct transaction_stats_s stats;
351 transaction_t *commit_transaction;
352 struct journal_head *jh;
353 struct buffer_head *descriptor;
354 struct buffer_head **wbuf = journal->j_wbuf;
355 int bufs;
356 int flags;
357 int err;
358 unsigned long long blocknr;
359 ktime_t start_time;
360 u64 commit_time;
361 char *tagp = NULL;
362 journal_block_tag_t *tag = NULL;
363 int space_left = 0;
364 int first_tag = 0;
365 int tag_flag;
366 int i;
367 int tag_bytes = journal_tag_bytes(journal);
368 struct buffer_head *cbh = NULL; /* For transactional checksums */
369 __u32 crc32_sum = ~0;
370 struct blk_plug plug;
371 /* Tail of the journal */
372 unsigned long first_block;
373 tid_t first_tid;
374 int update_tail;
375 int csum_size = 0;
376 LIST_HEAD(io_bufs);
377 LIST_HEAD(log_bufs);
378
379 if (jbd2_journal_has_csum_v2or3(journal))
380 csum_size = sizeof(struct jbd2_journal_block_tail);
381
382 /*
383 * First job: lock down the current transaction and wait for
384 * all outstanding updates to complete.
385 */
386
387 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
388 if (journal->j_flags & JBD2_FLUSHED) {
389 jbd2_debug(3, "super block updated\n");
390 mutex_lock_io(&journal->j_checkpoint_mutex);
391 /*
392 * We hold j_checkpoint_mutex so tail cannot change under us.
393 * We don't need any special data guarantees for writing sb
394 * since journal is empty and it is ok for write to be
395 * flushed only with transaction commit.
396 */
397 jbd2_journal_update_sb_log_tail(journal,
398 journal->j_tail_sequence,
399 journal->j_tail, 0);
400 mutex_unlock(&journal->j_checkpoint_mutex);
401 } else {
402 jbd2_debug(3, "superblock not updated\n");
403 }
404
405 J_ASSERT(journal->j_running_transaction != NULL);
406 J_ASSERT(journal->j_committing_transaction == NULL);
407
408 write_lock(&journal->j_state_lock);
409 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
410 while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
411 DEFINE_WAIT(wait);
412
413 prepare_to_wait(&journal->j_fc_wait, &wait,
414 TASK_UNINTERRUPTIBLE);
415 write_unlock(&journal->j_state_lock);
416 schedule();
417 write_lock(&journal->j_state_lock);
418 finish_wait(&journal->j_fc_wait, &wait);
419 /*
420 * TODO: by blocking fast commits here, we are increasing
421 * fsync() latency slightly. Strictly speaking, we don't need
422 * to block fast commits until the transaction enters T_FLUSH
423 * state. So an optimization is possible where we block new fast
424 * commits here and wait for existing ones to complete
425 * just before we enter T_FLUSH. That way, the existing fast
426 * commits and this full commit can proceed parallely.
427 */
428 }
429 write_unlock(&journal->j_state_lock);
430
431 commit_transaction = journal->j_running_transaction;
432
433 trace_jbd2_start_commit(journal, commit_transaction);
434 jbd2_debug(1, "JBD2: starting commit of transaction %d\n",
435 commit_transaction->t_tid);
436
437 write_lock(&journal->j_state_lock);
438 journal->j_fc_off = 0;
439 J_ASSERT(commit_transaction->t_state == T_RUNNING);
440 commit_transaction->t_state = T_LOCKED;
441
442 trace_jbd2_commit_locking(journal, commit_transaction);
443 stats.run.rs_wait = commit_transaction->t_max_wait;
444 stats.run.rs_request_delay = 0;
445 stats.run.rs_locked = jiffies;
446 if (commit_transaction->t_requested)
447 stats.run.rs_request_delay =
448 jbd2_time_diff(commit_transaction->t_requested,
449 stats.run.rs_locked);
450 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
451 stats.run.rs_locked);
452
453 // waits for any t_updates to finish
454 jbd2_journal_wait_updates(journal);
455
456 commit_transaction->t_state = T_SWITCH;
457
458 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
459 journal->j_max_transaction_buffers);
460
461 /*
462 * First thing we are allowed to do is to discard any remaining
463 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
464 * that there are no such buffers: if a large filesystem
465 * operation like a truncate needs to split itself over multiple
466 * transactions, then it may try to do a jbd2_journal_restart() while
467 * there are still BJ_Reserved buffers outstanding. These must
468 * be released cleanly from the current transaction.
469 *
470 * In this case, the filesystem must still reserve write access
471 * again before modifying the buffer in the new transaction, but
472 * we do not require it to remember exactly which old buffers it
473 * has reserved. This is consistent with the existing behaviour
474 * that multiple jbd2_journal_get_write_access() calls to the same
475 * buffer are perfectly permissible.
476 * We use journal->j_state_lock here to serialize processing of
477 * t_reserved_list with eviction of buffers from journal_unmap_buffer().
478 */
479 while (commit_transaction->t_reserved_list) {
480 jh = commit_transaction->t_reserved_list;
481 JBUFFER_TRACE(jh, "reserved, unused: refile");
482 /*
483 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
484 * leave undo-committed data.
485 */
486 if (jh->b_committed_data) {
487 struct buffer_head *bh = jh2bh(jh);
488
489 spin_lock(&jh->b_state_lock);
490 jbd2_free(jh->b_committed_data, bh->b_size);
491 jh->b_committed_data = NULL;
492 spin_unlock(&jh->b_state_lock);
493 }
494 jbd2_journal_refile_buffer(journal, jh);
495 }
496
497 write_unlock(&journal->j_state_lock);
498 /*
499 * Now try to drop any written-back buffers from the journal's
500 * checkpoint lists. We do this *before* commit because it potentially
501 * frees some memory
502 */
503 spin_lock(&journal->j_list_lock);
504 __jbd2_journal_clean_checkpoint_list(journal, false);
505 spin_unlock(&journal->j_list_lock);
506
507 jbd2_debug(3, "JBD2: commit phase 1\n");
508
509 /*
510 * Clear revoked flag to reflect there is no revoked buffers
511 * in the next transaction which is going to be started.
512 */
513 jbd2_clear_buffer_revoked_flags(journal);
514
515 /*
516 * Switch to a new revoke table.
517 */
518 jbd2_journal_switch_revoke_table(journal);
519
520 write_lock(&journal->j_state_lock);
521 /*
522 * Reserved credits cannot be claimed anymore, free them
523 */
524 atomic_sub(atomic_read(&journal->j_reserved_credits),
525 &commit_transaction->t_outstanding_credits);
526
527 trace_jbd2_commit_flushing(journal, commit_transaction);
528 stats.run.rs_flushing = jiffies;
529 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
530 stats.run.rs_flushing);
531
532 commit_transaction->t_state = T_FLUSH;
533 journal->j_committing_transaction = commit_transaction;
534 journal->j_running_transaction = NULL;
535 start_time = ktime_get();
536 commit_transaction->t_log_start = journal->j_head;
537 wake_up_all(&journal->j_wait_transaction_locked);
538 write_unlock(&journal->j_state_lock);
539
540 jbd2_debug(3, "JBD2: commit phase 2a\n");
541
542 /*
543 * Now start flushing things to disk, in the order they appear
544 * on the transaction lists. Data blocks go first.
545 */
546 err = journal_submit_data_buffers(journal, commit_transaction);
547 if (err)
548 jbd2_journal_abort(journal, err);
549
550 blk_start_plug(&plug);
551 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
552
553 jbd2_debug(3, "JBD2: commit phase 2b\n");
554
555 /*
556 * Way to go: we have now written out all of the data for a
557 * transaction! Now comes the tricky part: we need to write out
558 * metadata. Loop over the transaction's entire buffer list:
559 */
560 write_lock(&journal->j_state_lock);
561 commit_transaction->t_state = T_COMMIT;
562 write_unlock(&journal->j_state_lock);
563
564 trace_jbd2_commit_logging(journal, commit_transaction);
565 stats.run.rs_logging = jiffies;
566 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
567 stats.run.rs_logging);
568 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
569 stats.run.rs_blocks_logged = 0;
570
571 J_ASSERT(commit_transaction->t_nr_buffers <=
572 atomic_read(&commit_transaction->t_outstanding_credits));
573
574 err = 0;
575 bufs = 0;
576 descriptor = NULL;
577 while (commit_transaction->t_buffers) {
578
579 /* Find the next buffer to be journaled... */
580
581 jh = commit_transaction->t_buffers;
582
583 /* If we're in abort mode, we just un-journal the buffer and
584 release it. */
585
586 if (is_journal_aborted(journal)) {
587 clear_buffer_jbddirty(jh2bh(jh));
588 JBUFFER_TRACE(jh, "journal is aborting: refile");
589 jbd2_buffer_abort_trigger(jh,
590 jh->b_frozen_data ?
591 jh->b_frozen_triggers :
592 jh->b_triggers);
593 jbd2_journal_refile_buffer(journal, jh);
594 /* If that was the last one, we need to clean up
595 * any descriptor buffers which may have been
596 * already allocated, even if we are now
597 * aborting. */
598 if (!commit_transaction->t_buffers)
599 goto start_journal_io;
600 continue;
601 }
602
603 /* Make sure we have a descriptor block in which to
604 record the metadata buffer. */
605
606 if (!descriptor) {
607 J_ASSERT (bufs == 0);
608
609 jbd2_debug(4, "JBD2: get descriptor\n");
610
611 descriptor = jbd2_journal_get_descriptor_buffer(
612 commit_transaction,
613 JBD2_DESCRIPTOR_BLOCK);
614 if (!descriptor) {
615 jbd2_journal_abort(journal, -EIO);
616 continue;
617 }
618
619 jbd2_debug(4, "JBD2: got buffer %llu (%p)\n",
620 (unsigned long long)descriptor->b_blocknr,
621 descriptor->b_data);
622 tagp = &descriptor->b_data[sizeof(journal_header_t)];
623 space_left = descriptor->b_size -
624 sizeof(journal_header_t);
625 first_tag = 1;
626 set_buffer_jwrite(descriptor);
627 set_buffer_dirty(descriptor);
628 wbuf[bufs++] = descriptor;
629
630 /* Record it so that we can wait for IO
631 completion later */
632 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
633 jbd2_file_log_bh(&log_bufs, descriptor);
634 }
635
636 /* Where is the buffer to be written? */
637
638 err = jbd2_journal_next_log_block(journal, &blocknr);
639 /* If the block mapping failed, just abandon the buffer
640 and repeat this loop: we'll fall into the
641 refile-on-abort condition above. */
642 if (err) {
643 jbd2_journal_abort(journal, err);
644 continue;
645 }
646
647 /*
648 * start_this_handle() uses t_outstanding_credits to determine
649 * the free space in the log.
650 */
651 atomic_dec(&commit_transaction->t_outstanding_credits);
652
653 /* Bump b_count to prevent truncate from stumbling over
654 the shadowed buffer! @@@ This can go if we ever get
655 rid of the shadow pairing of buffers. */
656 atomic_inc(&jh2bh(jh)->b_count);
657
658 /*
659 * Make a temporary IO buffer with which to write it out
660 * (this will requeue the metadata buffer to BJ_Shadow).
661 */
662 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
663 JBUFFER_TRACE(jh, "ph3: write metadata");
664 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
665 jh, &wbuf[bufs], blocknr);
666 if (flags < 0) {
667 jbd2_journal_abort(journal, flags);
668 continue;
669 }
670 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
671
672 /* Record the new block's tag in the current descriptor
673 buffer */
674
675 tag_flag = 0;
676 if (flags & 1)
677 tag_flag |= JBD2_FLAG_ESCAPE;
678 if (!first_tag)
679 tag_flag |= JBD2_FLAG_SAME_UUID;
680
681 tag = (journal_block_tag_t *) tagp;
682 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
683 tag->t_flags = cpu_to_be16(tag_flag);
684 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
685 commit_transaction->t_tid);
686 tagp += tag_bytes;
687 space_left -= tag_bytes;
688 bufs++;
689
690 if (first_tag) {
691 memcpy (tagp, journal->j_uuid, 16);
692 tagp += 16;
693 space_left -= 16;
694 first_tag = 0;
695 }
696
697 /* If there's no more to do, or if the descriptor is full,
698 let the IO rip! */
699
700 if (bufs == journal->j_wbufsize ||
701 commit_transaction->t_buffers == NULL ||
702 space_left < tag_bytes + 16 + csum_size) {
703
704 jbd2_debug(4, "JBD2: Submit %d IOs\n", bufs);
705
706 /* Write an end-of-descriptor marker before
707 submitting the IOs. "tag" still points to
708 the last tag we set up. */
709
710 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
711start_journal_io:
712 if (descriptor)
713 jbd2_descriptor_block_csum_set(journal,
714 descriptor);
715
716 for (i = 0; i < bufs; i++) {
717 struct buffer_head *bh = wbuf[i];
718
719 /*
720 * Compute checksum.
721 */
722 if (jbd2_has_feature_checksum(journal)) {
723 crc32_sum =
724 jbd2_checksum_data(crc32_sum, bh);
725 }
726
727 lock_buffer(bh);
728 clear_buffer_dirty(bh);
729 set_buffer_uptodate(bh);
730 bh->b_end_io = journal_end_buffer_io_sync;
731 submit_bh(REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS,
732 bh);
733 }
734 cond_resched();
735
736 /* Force a new descriptor to be generated next
737 time round the loop. */
738 descriptor = NULL;
739 bufs = 0;
740 }
741 }
742
743 err = journal_finish_inode_data_buffers(journal, commit_transaction);
744 if (err) {
745 printk(KERN_WARNING
746 "JBD2: Detected IO errors while flushing file data "
747 "on %s\n", journal->j_devname);
748 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
749 jbd2_journal_abort(journal, err);
750 err = 0;
751 }
752
753 /*
754 * Get current oldest transaction in the log before we issue flush
755 * to the filesystem device. After the flush we can be sure that
756 * blocks of all older transactions are checkpointed to persistent
757 * storage and we will be safe to update journal start in the
758 * superblock with the numbers we get here.
759 */
760 update_tail =
761 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
762
763 write_lock(&journal->j_state_lock);
764 if (update_tail) {
765 long freed = first_block - journal->j_tail;
766
767 if (first_block < journal->j_tail)
768 freed += journal->j_last - journal->j_first;
769 /* Update tail only if we free significant amount of space */
770 if (freed < jbd2_journal_get_max_txn_bufs(journal))
771 update_tail = 0;
772 }
773 J_ASSERT(commit_transaction->t_state == T_COMMIT);
774 commit_transaction->t_state = T_COMMIT_DFLUSH;
775 write_unlock(&journal->j_state_lock);
776
777 /*
778 * If the journal is not located on the file system device,
779 * then we must flush the file system device before we issue
780 * the commit record
781 */
782 if (commit_transaction->t_need_data_flush &&
783 (journal->j_fs_dev != journal->j_dev) &&
784 (journal->j_flags & JBD2_BARRIER))
785 blkdev_issue_flush(journal->j_fs_dev);
786
787 /* Done it all: now write the commit record asynchronously. */
788 if (jbd2_has_feature_async_commit(journal)) {
789 err = journal_submit_commit_record(journal, commit_transaction,
790 &cbh, crc32_sum);
791 if (err)
792 jbd2_journal_abort(journal, err);
793 }
794
795 blk_finish_plug(&plug);
796
797 /* Lo and behold: we have just managed to send a transaction to
798 the log. Before we can commit it, wait for the IO so far to
799 complete. Control buffers being written are on the
800 transaction's t_log_list queue, and metadata buffers are on
801 the io_bufs list.
802
803 Wait for the buffers in reverse order. That way we are
804 less likely to be woken up until all IOs have completed, and
805 so we incur less scheduling load.
806 */
807
808 jbd2_debug(3, "JBD2: commit phase 3\n");
809
810 while (!list_empty(&io_bufs)) {
811 struct buffer_head *bh = list_entry(io_bufs.prev,
812 struct buffer_head,
813 b_assoc_buffers);
814
815 wait_on_buffer(bh);
816 cond_resched();
817
818 if (unlikely(!buffer_uptodate(bh)))
819 err = -EIO;
820 jbd2_unfile_log_bh(bh);
821 stats.run.rs_blocks_logged++;
822
823 /*
824 * The list contains temporary buffer heads created by
825 * jbd2_journal_write_metadata_buffer().
826 */
827 BUFFER_TRACE(bh, "dumping temporary bh");
828 __brelse(bh);
829 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
830 free_buffer_head(bh);
831
832 /* We also have to refile the corresponding shadowed buffer */
833 jh = commit_transaction->t_shadow_list->b_tprev;
834 bh = jh2bh(jh);
835 clear_buffer_jwrite(bh);
836 J_ASSERT_BH(bh, buffer_jbddirty(bh));
837 J_ASSERT_BH(bh, !buffer_shadow(bh));
838
839 /* The metadata is now released for reuse, but we need
840 to remember it against this transaction so that when
841 we finally commit, we can do any checkpointing
842 required. */
843 JBUFFER_TRACE(jh, "file as BJ_Forget");
844 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
845 JBUFFER_TRACE(jh, "brelse shadowed buffer");
846 __brelse(bh);
847 }
848
849 J_ASSERT (commit_transaction->t_shadow_list == NULL);
850
851 jbd2_debug(3, "JBD2: commit phase 4\n");
852
853 /* Here we wait for the revoke record and descriptor record buffers */
854 while (!list_empty(&log_bufs)) {
855 struct buffer_head *bh;
856
857 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
858 wait_on_buffer(bh);
859 cond_resched();
860
861 if (unlikely(!buffer_uptodate(bh)))
862 err = -EIO;
863
864 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
865 clear_buffer_jwrite(bh);
866 jbd2_unfile_log_bh(bh);
867 stats.run.rs_blocks_logged++;
868 __brelse(bh); /* One for getblk */
869 /* AKPM: bforget here */
870 }
871
872 if (err)
873 jbd2_journal_abort(journal, err);
874
875 jbd2_debug(3, "JBD2: commit phase 5\n");
876 write_lock(&journal->j_state_lock);
877 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
878 commit_transaction->t_state = T_COMMIT_JFLUSH;
879 write_unlock(&journal->j_state_lock);
880
881 if (!jbd2_has_feature_async_commit(journal)) {
882 err = journal_submit_commit_record(journal, commit_transaction,
883 &cbh, crc32_sum);
884 if (err)
885 jbd2_journal_abort(journal, err);
886 }
887 if (cbh)
888 err = journal_wait_on_commit_record(journal, cbh);
889 stats.run.rs_blocks_logged++;
890 if (jbd2_has_feature_async_commit(journal) &&
891 journal->j_flags & JBD2_BARRIER) {
892 blkdev_issue_flush(journal->j_dev);
893 }
894
895 if (err)
896 jbd2_journal_abort(journal, err);
897
898 WARN_ON_ONCE(
899 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
900
901 /*
902 * Now disk caches for filesystem device are flushed so we are safe to
903 * erase checkpointed transactions from the log by updating journal
904 * superblock.
905 */
906 if (update_tail)
907 jbd2_update_log_tail(journal, first_tid, first_block);
908
909 /* End of a transaction! Finally, we can do checkpoint
910 processing: any buffers committed as a result of this
911 transaction can be removed from any checkpoint list it was on
912 before. */
913
914 jbd2_debug(3, "JBD2: commit phase 6\n");
915
916 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
917 J_ASSERT(commit_transaction->t_buffers == NULL);
918 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
919 J_ASSERT(commit_transaction->t_shadow_list == NULL);
920
921restart_loop:
922 /*
923 * As there are other places (journal_unmap_buffer()) adding buffers
924 * to this list we have to be careful and hold the j_list_lock.
925 */
926 spin_lock(&journal->j_list_lock);
927 while (commit_transaction->t_forget) {
928 transaction_t *cp_transaction;
929 struct buffer_head *bh;
930 int try_to_free = 0;
931 bool drop_ref;
932
933 jh = commit_transaction->t_forget;
934 spin_unlock(&journal->j_list_lock);
935 bh = jh2bh(jh);
936 /*
937 * Get a reference so that bh cannot be freed before we are
938 * done with it.
939 */
940 get_bh(bh);
941 spin_lock(&jh->b_state_lock);
942 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
943
944 /*
945 * If there is undo-protected committed data against
946 * this buffer, then we can remove it now. If it is a
947 * buffer needing such protection, the old frozen_data
948 * field now points to a committed version of the
949 * buffer, so rotate that field to the new committed
950 * data.
951 *
952 * Otherwise, we can just throw away the frozen data now.
953 *
954 * We also know that the frozen data has already fired
955 * its triggers if they exist, so we can clear that too.
956 */
957 if (jh->b_committed_data) {
958 jbd2_free(jh->b_committed_data, bh->b_size);
959 jh->b_committed_data = NULL;
960 if (jh->b_frozen_data) {
961 jh->b_committed_data = jh->b_frozen_data;
962 jh->b_frozen_data = NULL;
963 jh->b_frozen_triggers = NULL;
964 }
965 } else if (jh->b_frozen_data) {
966 jbd2_free(jh->b_frozen_data, bh->b_size);
967 jh->b_frozen_data = NULL;
968 jh->b_frozen_triggers = NULL;
969 }
970
971 spin_lock(&journal->j_list_lock);
972 cp_transaction = jh->b_cp_transaction;
973 if (cp_transaction) {
974 JBUFFER_TRACE(jh, "remove from old cp transaction");
975 cp_transaction->t_chp_stats.cs_dropped++;
976 __jbd2_journal_remove_checkpoint(jh);
977 }
978
979 /* Only re-checkpoint the buffer_head if it is marked
980 * dirty. If the buffer was added to the BJ_Forget list
981 * by jbd2_journal_forget, it may no longer be dirty and
982 * there's no point in keeping a checkpoint record for
983 * it. */
984
985 /*
986 * A buffer which has been freed while still being journaled
987 * by a previous transaction, refile the buffer to BJ_Forget of
988 * the running transaction. If the just committed transaction
989 * contains "add to orphan" operation, we can completely
990 * invalidate the buffer now. We are rather through in that
991 * since the buffer may be still accessible when blocksize <
992 * pagesize and it is attached to the last partial page.
993 */
994 if (buffer_freed(bh) && !jh->b_next_transaction) {
995 struct address_space *mapping;
996
997 clear_buffer_freed(bh);
998 clear_buffer_jbddirty(bh);
999
1000 /*
1001 * Block device buffers need to stay mapped all the
1002 * time, so it is enough to clear buffer_jbddirty and
1003 * buffer_freed bits. For the file mapping buffers (i.e.
1004 * journalled data) we need to unmap buffer and clear
1005 * more bits. We also need to be careful about the check
1006 * because the data page mapping can get cleared under
1007 * our hands. Note that if mapping == NULL, we don't
1008 * need to make buffer unmapped because the page is
1009 * already detached from the mapping and buffers cannot
1010 * get reused.
1011 */
1012 mapping = READ_ONCE(bh->b_folio->mapping);
1013 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1014 clear_buffer_mapped(bh);
1015 clear_buffer_new(bh);
1016 clear_buffer_req(bh);
1017 bh->b_bdev = NULL;
1018 }
1019 }
1020
1021 if (buffer_jbddirty(bh)) {
1022 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1023 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1024 if (is_journal_aborted(journal))
1025 clear_buffer_jbddirty(bh);
1026 } else {
1027 J_ASSERT_BH(bh, !buffer_dirty(bh));
1028 /*
1029 * The buffer on BJ_Forget list and not jbddirty means
1030 * it has been freed by this transaction and hence it
1031 * could not have been reallocated until this
1032 * transaction has committed. *BUT* it could be
1033 * reallocated once we have written all the data to
1034 * disk and before we process the buffer on BJ_Forget
1035 * list.
1036 */
1037 if (!jh->b_next_transaction)
1038 try_to_free = 1;
1039 }
1040 JBUFFER_TRACE(jh, "refile or unfile buffer");
1041 drop_ref = __jbd2_journal_refile_buffer(jh);
1042 spin_unlock(&jh->b_state_lock);
1043 if (drop_ref)
1044 jbd2_journal_put_journal_head(jh);
1045 if (try_to_free)
1046 release_buffer_page(bh); /* Drops bh reference */
1047 else
1048 __brelse(bh);
1049 cond_resched_lock(&journal->j_list_lock);
1050 }
1051 spin_unlock(&journal->j_list_lock);
1052 /*
1053 * This is a bit sleazy. We use j_list_lock to protect transition
1054 * of a transaction into T_FINISHED state and calling
1055 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1056 * other checkpointing code processing the transaction...
1057 */
1058 write_lock(&journal->j_state_lock);
1059 spin_lock(&journal->j_list_lock);
1060 /*
1061 * Now recheck if some buffers did not get attached to the transaction
1062 * while the lock was dropped...
1063 */
1064 if (commit_transaction->t_forget) {
1065 spin_unlock(&journal->j_list_lock);
1066 write_unlock(&journal->j_state_lock);
1067 goto restart_loop;
1068 }
1069
1070 /* Add the transaction to the checkpoint list
1071 * __journal_remove_checkpoint() can not destroy transaction
1072 * under us because it is not marked as T_FINISHED yet */
1073 if (journal->j_checkpoint_transactions == NULL) {
1074 journal->j_checkpoint_transactions = commit_transaction;
1075 commit_transaction->t_cpnext = commit_transaction;
1076 commit_transaction->t_cpprev = commit_transaction;
1077 } else {
1078 commit_transaction->t_cpnext =
1079 journal->j_checkpoint_transactions;
1080 commit_transaction->t_cpprev =
1081 commit_transaction->t_cpnext->t_cpprev;
1082 commit_transaction->t_cpnext->t_cpprev =
1083 commit_transaction;
1084 commit_transaction->t_cpprev->t_cpnext =
1085 commit_transaction;
1086 }
1087 spin_unlock(&journal->j_list_lock);
1088
1089 /* Done with this transaction! */
1090
1091 jbd2_debug(3, "JBD2: commit phase 7\n");
1092
1093 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1094
1095 commit_transaction->t_start = jiffies;
1096 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1097 commit_transaction->t_start);
1098
1099 /*
1100 * File the transaction statistics
1101 */
1102 stats.ts_tid = commit_transaction->t_tid;
1103 stats.run.rs_handle_count =
1104 atomic_read(&commit_transaction->t_handle_count);
1105 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1106 commit_transaction->t_tid, &stats.run);
1107 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1108
1109 commit_transaction->t_state = T_COMMIT_CALLBACK;
1110 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1111 journal->j_commit_sequence = commit_transaction->t_tid;
1112 journal->j_committing_transaction = NULL;
1113 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1114
1115 /*
1116 * weight the commit time higher than the average time so we don't
1117 * react too strongly to vast changes in the commit time
1118 */
1119 if (likely(journal->j_average_commit_time))
1120 journal->j_average_commit_time = (commit_time +
1121 journal->j_average_commit_time*3) / 4;
1122 else
1123 journal->j_average_commit_time = commit_time;
1124
1125 write_unlock(&journal->j_state_lock);
1126
1127 if (journal->j_commit_callback)
1128 journal->j_commit_callback(journal, commit_transaction);
1129 if (journal->j_fc_cleanup_callback)
1130 journal->j_fc_cleanup_callback(journal, 1, commit_transaction->t_tid);
1131
1132 trace_jbd2_end_commit(journal, commit_transaction);
1133 jbd2_debug(1, "JBD2: commit %d complete, head %d\n",
1134 journal->j_commit_sequence, journal->j_tail_sequence);
1135
1136 write_lock(&journal->j_state_lock);
1137 journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1138 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1139 spin_lock(&journal->j_list_lock);
1140 commit_transaction->t_state = T_FINISHED;
1141 /* Check if the transaction can be dropped now that we are finished */
1142 if (commit_transaction->t_checkpoint_list == NULL) {
1143 __jbd2_journal_drop_transaction(journal, commit_transaction);
1144 jbd2_journal_free_transaction(commit_transaction);
1145 }
1146 spin_unlock(&journal->j_list_lock);
1147 write_unlock(&journal->j_state_lock);
1148 wake_up(&journal->j_wait_done_commit);
1149 wake_up(&journal->j_fc_wait);
1150
1151 /*
1152 * Calculate overall stats
1153 */
1154 spin_lock(&journal->j_history_lock);
1155 journal->j_stats.ts_tid++;
1156 journal->j_stats.ts_requested += stats.ts_requested;
1157 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1158 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1159 journal->j_stats.run.rs_running += stats.run.rs_running;
1160 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1161 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1162 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1163 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1164 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1165 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1166 spin_unlock(&journal->j_history_lock);
1167}