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