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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#include <asm/system.h>
32
33/*
34 * Default IO end handler for temporary BJ_IO buffer_heads.
35 */
36static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
37{
38 BUFFER_TRACE(bh, "");
39 if (uptodate)
40 set_buffer_uptodate(bh);
41 else
42 clear_buffer_uptodate(bh);
43 unlock_buffer(bh);
44}
45
46/*
47 * When an ext4 file is truncated, it is possible that some pages are not
48 * successfully freed, because they are attached to a committing transaction.
49 * After the transaction commits, these pages are left on the LRU, with no
50 * ->mapping, and with attached buffers. These pages are trivially reclaimable
51 * by the VM, but their apparent absence upsets the VM accounting, and it makes
52 * the numbers in /proc/meminfo look odd.
53 *
54 * So here, we have a buffer which has just come off the forget list. Look to
55 * see if we can strip all buffers from the backing page.
56 *
57 * Called under lock_journal(), and possibly under journal_datalist_lock. The
58 * caller provided us with a ref against the buffer, and we drop that here.
59 */
60static void release_buffer_page(struct buffer_head *bh)
61{
62 struct page *page;
63
64 if (buffer_dirty(bh))
65 goto nope;
66 if (atomic_read(&bh->b_count) != 1)
67 goto nope;
68 page = bh->b_page;
69 if (!page)
70 goto nope;
71 if (page->mapping)
72 goto nope;
73
74 /* OK, it's a truncated page */
75 if (!trylock_page(page))
76 goto nope;
77
78 page_cache_get(page);
79 __brelse(bh);
80 try_to_free_buffers(page);
81 unlock_page(page);
82 page_cache_release(page);
83 return;
84
85nope:
86 __brelse(bh);
87}
88
89/*
90 * Done it all: now submit the commit record. We should have
91 * cleaned up our previous buffers by now, so if we are in abort
92 * mode we can now just skip the rest of the journal write
93 * entirely.
94 *
95 * Returns 1 if the journal needs to be aborted or 0 on success
96 */
97static int journal_submit_commit_record(journal_t *journal,
98 transaction_t *commit_transaction,
99 struct buffer_head **cbh,
100 __u32 crc32_sum)
101{
102 struct journal_head *descriptor;
103 struct commit_header *tmp;
104 struct buffer_head *bh;
105 int ret;
106 struct timespec now = current_kernel_time();
107
108 *cbh = NULL;
109
110 if (is_journal_aborted(journal))
111 return 0;
112
113 descriptor = jbd2_journal_get_descriptor_buffer(journal);
114 if (!descriptor)
115 return 1;
116
117 bh = jh2bh(descriptor);
118
119 tmp = (struct commit_header *)bh->b_data;
120 tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
121 tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK);
122 tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
123 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
124 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
125
126 if (JBD2_HAS_COMPAT_FEATURE(journal,
127 JBD2_FEATURE_COMPAT_CHECKSUM)) {
128 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
129 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
130 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
131 }
132
133 JBUFFER_TRACE(descriptor, "submit commit block");
134 lock_buffer(bh);
135 clear_buffer_dirty(bh);
136 set_buffer_uptodate(bh);
137 bh->b_end_io = journal_end_buffer_io_sync;
138
139 if (journal->j_flags & JBD2_BARRIER &&
140 !JBD2_HAS_INCOMPAT_FEATURE(journal,
141 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT))
142 ret = submit_bh(WRITE_SYNC | WRITE_FLUSH_FUA, bh);
143 else
144 ret = submit_bh(WRITE_SYNC, bh);
145
146 *cbh = bh;
147 return ret;
148}
149
150/*
151 * This function along with journal_submit_commit_record
152 * allows to write the commit record asynchronously.
153 */
154static int journal_wait_on_commit_record(journal_t *journal,
155 struct buffer_head *bh)
156{
157 int ret = 0;
158
159 clear_buffer_dirty(bh);
160 wait_on_buffer(bh);
161
162 if (unlikely(!buffer_uptodate(bh)))
163 ret = -EIO;
164 put_bh(bh); /* One for getblk() */
165 jbd2_journal_put_journal_head(bh2jh(bh));
166
167 return ret;
168}
169
170/*
171 * write the filemap data using writepage() address_space_operations.
172 * We don't do block allocation here even for delalloc. We don't
173 * use writepages() because with dealyed allocation we may be doing
174 * block allocation in writepages().
175 */
176static int journal_submit_inode_data_buffers(struct address_space *mapping)
177{
178 int ret;
179 struct writeback_control wbc = {
180 .sync_mode = WB_SYNC_ALL,
181 .nr_to_write = mapping->nrpages * 2,
182 .range_start = 0,
183 .range_end = i_size_read(mapping->host),
184 };
185
186 ret = generic_writepages(mapping, &wbc);
187 return ret;
188}
189
190/*
191 * Submit all the data buffers of inode associated with the transaction to
192 * disk.
193 *
194 * We are in a committing transaction. Therefore no new inode can be added to
195 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
196 * operate on from being released while we write out pages.
197 */
198static int journal_submit_data_buffers(journal_t *journal,
199 transaction_t *commit_transaction)
200{
201 struct jbd2_inode *jinode;
202 int err, ret = 0;
203 struct address_space *mapping;
204
205 spin_lock(&journal->j_list_lock);
206 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
207 mapping = jinode->i_vfs_inode->i_mapping;
208 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
209 spin_unlock(&journal->j_list_lock);
210 /*
211 * submit the inode data buffers. We use writepage
212 * instead of writepages. Because writepages can do
213 * block allocation with delalloc. We need to write
214 * only allocated blocks here.
215 */
216 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
217 err = journal_submit_inode_data_buffers(mapping);
218 if (!ret)
219 ret = err;
220 spin_lock(&journal->j_list_lock);
221 J_ASSERT(jinode->i_transaction == commit_transaction);
222 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
223 smp_mb__after_clear_bit();
224 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
225 }
226 spin_unlock(&journal->j_list_lock);
227 return ret;
228}
229
230/*
231 * Wait for data submitted for writeout, refile inodes to proper
232 * transaction if needed.
233 *
234 */
235static int journal_finish_inode_data_buffers(journal_t *journal,
236 transaction_t *commit_transaction)
237{
238 struct jbd2_inode *jinode, *next_i;
239 int err, ret = 0;
240
241 /* For locking, see the comment in journal_submit_data_buffers() */
242 spin_lock(&journal->j_list_lock);
243 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
244 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
245 spin_unlock(&journal->j_list_lock);
246 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
247 if (err) {
248 /*
249 * Because AS_EIO is cleared by
250 * filemap_fdatawait_range(), set it again so
251 * that user process can get -EIO from fsync().
252 */
253 set_bit(AS_EIO,
254 &jinode->i_vfs_inode->i_mapping->flags);
255
256 if (!ret)
257 ret = err;
258 }
259 spin_lock(&journal->j_list_lock);
260 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
261 smp_mb__after_clear_bit();
262 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
263 }
264
265 /* Now refile inode to proper lists */
266 list_for_each_entry_safe(jinode, next_i,
267 &commit_transaction->t_inode_list, i_list) {
268 list_del(&jinode->i_list);
269 if (jinode->i_next_transaction) {
270 jinode->i_transaction = jinode->i_next_transaction;
271 jinode->i_next_transaction = NULL;
272 list_add(&jinode->i_list,
273 &jinode->i_transaction->t_inode_list);
274 } else {
275 jinode->i_transaction = NULL;
276 }
277 }
278 spin_unlock(&journal->j_list_lock);
279
280 return ret;
281}
282
283static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
284{
285 struct page *page = bh->b_page;
286 char *addr;
287 __u32 checksum;
288
289 addr = kmap_atomic(page, KM_USER0);
290 checksum = crc32_be(crc32_sum,
291 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
292 kunmap_atomic(addr, KM_USER0);
293
294 return checksum;
295}
296
297static void write_tag_block(int tag_bytes, journal_block_tag_t *tag,
298 unsigned long long block)
299{
300 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
301 if (tag_bytes > JBD2_TAG_SIZE32)
302 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
303}
304
305/*
306 * jbd2_journal_commit_transaction
307 *
308 * The primary function for committing a transaction to the log. This
309 * function is called by the journal thread to begin a complete commit.
310 */
311void jbd2_journal_commit_transaction(journal_t *journal)
312{
313 struct transaction_stats_s stats;
314 transaction_t *commit_transaction;
315 struct journal_head *jh, *new_jh, *descriptor;
316 struct buffer_head **wbuf = journal->j_wbuf;
317 int bufs;
318 int flags;
319 int err;
320 unsigned long long blocknr;
321 ktime_t start_time;
322 u64 commit_time;
323 char *tagp = NULL;
324 journal_header_t *header;
325 journal_block_tag_t *tag = NULL;
326 int space_left = 0;
327 int first_tag = 0;
328 int tag_flag;
329 int i, to_free = 0;
330 int tag_bytes = journal_tag_bytes(journal);
331 struct buffer_head *cbh = NULL; /* For transactional checksums */
332 __u32 crc32_sum = ~0;
333 struct blk_plug plug;
334
335 /*
336 * First job: lock down the current transaction and wait for
337 * all outstanding updates to complete.
338 */
339
340 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
341 if (journal->j_flags & JBD2_FLUSHED) {
342 jbd_debug(3, "super block updated\n");
343 jbd2_journal_update_superblock(journal, 1);
344 } else {
345 jbd_debug(3, "superblock not updated\n");
346 }
347
348 J_ASSERT(journal->j_running_transaction != NULL);
349 J_ASSERT(journal->j_committing_transaction == NULL);
350
351 commit_transaction = journal->j_running_transaction;
352 J_ASSERT(commit_transaction->t_state == T_RUNNING);
353
354 trace_jbd2_start_commit(journal, commit_transaction);
355 jbd_debug(1, "JBD: starting commit of transaction %d\n",
356 commit_transaction->t_tid);
357
358 write_lock(&journal->j_state_lock);
359 commit_transaction->t_state = T_LOCKED;
360
361 trace_jbd2_commit_locking(journal, commit_transaction);
362 stats.run.rs_wait = commit_transaction->t_max_wait;
363 stats.run.rs_locked = jiffies;
364 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
365 stats.run.rs_locked);
366
367 spin_lock(&commit_transaction->t_handle_lock);
368 while (atomic_read(&commit_transaction->t_updates)) {
369 DEFINE_WAIT(wait);
370
371 prepare_to_wait(&journal->j_wait_updates, &wait,
372 TASK_UNINTERRUPTIBLE);
373 if (atomic_read(&commit_transaction->t_updates)) {
374 spin_unlock(&commit_transaction->t_handle_lock);
375 write_unlock(&journal->j_state_lock);
376 schedule();
377 write_lock(&journal->j_state_lock);
378 spin_lock(&commit_transaction->t_handle_lock);
379 }
380 finish_wait(&journal->j_wait_updates, &wait);
381 }
382 spin_unlock(&commit_transaction->t_handle_lock);
383
384 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
385 journal->j_max_transaction_buffers);
386
387 /*
388 * First thing we are allowed to do is to discard any remaining
389 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
390 * that there are no such buffers: if a large filesystem
391 * operation like a truncate needs to split itself over multiple
392 * transactions, then it may try to do a jbd2_journal_restart() while
393 * there are still BJ_Reserved buffers outstanding. These must
394 * be released cleanly from the current transaction.
395 *
396 * In this case, the filesystem must still reserve write access
397 * again before modifying the buffer in the new transaction, but
398 * we do not require it to remember exactly which old buffers it
399 * has reserved. This is consistent with the existing behaviour
400 * that multiple jbd2_journal_get_write_access() calls to the same
401 * buffer are perfectly permissible.
402 */
403 while (commit_transaction->t_reserved_list) {
404 jh = commit_transaction->t_reserved_list;
405 JBUFFER_TRACE(jh, "reserved, unused: refile");
406 /*
407 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
408 * leave undo-committed data.
409 */
410 if (jh->b_committed_data) {
411 struct buffer_head *bh = jh2bh(jh);
412
413 jbd_lock_bh_state(bh);
414 jbd2_free(jh->b_committed_data, bh->b_size);
415 jh->b_committed_data = NULL;
416 jbd_unlock_bh_state(bh);
417 }
418 jbd2_journal_refile_buffer(journal, jh);
419 }
420
421 /*
422 * Now try to drop any written-back buffers from the journal's
423 * checkpoint lists. We do this *before* commit because it potentially
424 * frees some memory
425 */
426 spin_lock(&journal->j_list_lock);
427 __jbd2_journal_clean_checkpoint_list(journal);
428 spin_unlock(&journal->j_list_lock);
429
430 jbd_debug (3, "JBD: commit phase 1\n");
431
432 /*
433 * Switch to a new revoke table.
434 */
435 jbd2_journal_switch_revoke_table(journal);
436
437 trace_jbd2_commit_flushing(journal, commit_transaction);
438 stats.run.rs_flushing = jiffies;
439 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
440 stats.run.rs_flushing);
441
442 commit_transaction->t_state = T_FLUSH;
443 journal->j_committing_transaction = commit_transaction;
444 journal->j_running_transaction = NULL;
445 start_time = ktime_get();
446 commit_transaction->t_log_start = journal->j_head;
447 wake_up(&journal->j_wait_transaction_locked);
448 write_unlock(&journal->j_state_lock);
449
450 jbd_debug (3, "JBD: commit phase 2\n");
451
452 /*
453 * Now start flushing things to disk, in the order they appear
454 * on the transaction lists. Data blocks go first.
455 */
456 err = journal_submit_data_buffers(journal, commit_transaction);
457 if (err)
458 jbd2_journal_abort(journal, err);
459
460 blk_start_plug(&plug);
461 jbd2_journal_write_revoke_records(journal, commit_transaction,
462 WRITE_SYNC);
463 blk_finish_plug(&plug);
464
465 jbd_debug(3, "JBD: commit phase 2\n");
466
467 /*
468 * Way to go: we have now written out all of the data for a
469 * transaction! Now comes the tricky part: we need to write out
470 * metadata. Loop over the transaction's entire buffer list:
471 */
472 write_lock(&journal->j_state_lock);
473 commit_transaction->t_state = T_COMMIT;
474 write_unlock(&journal->j_state_lock);
475
476 trace_jbd2_commit_logging(journal, commit_transaction);
477 stats.run.rs_logging = jiffies;
478 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
479 stats.run.rs_logging);
480 stats.run.rs_blocks =
481 atomic_read(&commit_transaction->t_outstanding_credits);
482 stats.run.rs_blocks_logged = 0;
483
484 J_ASSERT(commit_transaction->t_nr_buffers <=
485 atomic_read(&commit_transaction->t_outstanding_credits));
486
487 err = 0;
488 descriptor = NULL;
489 bufs = 0;
490 blk_start_plug(&plug);
491 while (commit_transaction->t_buffers) {
492
493 /* Find the next buffer to be journaled... */
494
495 jh = commit_transaction->t_buffers;
496
497 /* If we're in abort mode, we just un-journal the buffer and
498 release it. */
499
500 if (is_journal_aborted(journal)) {
501 clear_buffer_jbddirty(jh2bh(jh));
502 JBUFFER_TRACE(jh, "journal is aborting: refile");
503 jbd2_buffer_abort_trigger(jh,
504 jh->b_frozen_data ?
505 jh->b_frozen_triggers :
506 jh->b_triggers);
507 jbd2_journal_refile_buffer(journal, jh);
508 /* If that was the last one, we need to clean up
509 * any descriptor buffers which may have been
510 * already allocated, even if we are now
511 * aborting. */
512 if (!commit_transaction->t_buffers)
513 goto start_journal_io;
514 continue;
515 }
516
517 /* Make sure we have a descriptor block in which to
518 record the metadata buffer. */
519
520 if (!descriptor) {
521 struct buffer_head *bh;
522
523 J_ASSERT (bufs == 0);
524
525 jbd_debug(4, "JBD: get descriptor\n");
526
527 descriptor = jbd2_journal_get_descriptor_buffer(journal);
528 if (!descriptor) {
529 jbd2_journal_abort(journal, -EIO);
530 continue;
531 }
532
533 bh = jh2bh(descriptor);
534 jbd_debug(4, "JBD: got buffer %llu (%p)\n",
535 (unsigned long long)bh->b_blocknr, bh->b_data);
536 header = (journal_header_t *)&bh->b_data[0];
537 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
538 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK);
539 header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
540
541 tagp = &bh->b_data[sizeof(journal_header_t)];
542 space_left = bh->b_size - sizeof(journal_header_t);
543 first_tag = 1;
544 set_buffer_jwrite(bh);
545 set_buffer_dirty(bh);
546 wbuf[bufs++] = bh;
547
548 /* Record it so that we can wait for IO
549 completion later */
550 BUFFER_TRACE(bh, "ph3: file as descriptor");
551 jbd2_journal_file_buffer(descriptor, commit_transaction,
552 BJ_LogCtl);
553 }
554
555 /* Where is the buffer to be written? */
556
557 err = jbd2_journal_next_log_block(journal, &blocknr);
558 /* If the block mapping failed, just abandon the buffer
559 and repeat this loop: we'll fall into the
560 refile-on-abort condition above. */
561 if (err) {
562 jbd2_journal_abort(journal, err);
563 continue;
564 }
565
566 /*
567 * start_this_handle() uses t_outstanding_credits to determine
568 * the free space in the log, but this counter is changed
569 * by jbd2_journal_next_log_block() also.
570 */
571 atomic_dec(&commit_transaction->t_outstanding_credits);
572
573 /* Bump b_count to prevent truncate from stumbling over
574 the shadowed buffer! @@@ This can go if we ever get
575 rid of the BJ_IO/BJ_Shadow pairing of buffers. */
576 atomic_inc(&jh2bh(jh)->b_count);
577
578 /* Make a temporary IO buffer with which to write it out
579 (this will requeue both the metadata buffer and the
580 temporary IO buffer). new_bh goes on BJ_IO*/
581
582 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
583 /*
584 * akpm: jbd2_journal_write_metadata_buffer() sets
585 * new_bh->b_transaction to commit_transaction.
586 * We need to clean this up before we release new_bh
587 * (which is of type BJ_IO)
588 */
589 JBUFFER_TRACE(jh, "ph3: write metadata");
590 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
591 jh, &new_jh, blocknr);
592 if (flags < 0) {
593 jbd2_journal_abort(journal, flags);
594 continue;
595 }
596 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state);
597 wbuf[bufs++] = jh2bh(new_jh);
598
599 /* Record the new block's tag in the current descriptor
600 buffer */
601
602 tag_flag = 0;
603 if (flags & 1)
604 tag_flag |= JBD2_FLAG_ESCAPE;
605 if (!first_tag)
606 tag_flag |= JBD2_FLAG_SAME_UUID;
607
608 tag = (journal_block_tag_t *) tagp;
609 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr);
610 tag->t_flags = cpu_to_be32(tag_flag);
611 tagp += tag_bytes;
612 space_left -= tag_bytes;
613
614 if (first_tag) {
615 memcpy (tagp, journal->j_uuid, 16);
616 tagp += 16;
617 space_left -= 16;
618 first_tag = 0;
619 }
620
621 /* If there's no more to do, or if the descriptor is full,
622 let the IO rip! */
623
624 if (bufs == journal->j_wbufsize ||
625 commit_transaction->t_buffers == NULL ||
626 space_left < tag_bytes + 16) {
627
628 jbd_debug(4, "JBD: Submit %d IOs\n", bufs);
629
630 /* Write an end-of-descriptor marker before
631 submitting the IOs. "tag" still points to
632 the last tag we set up. */
633
634 tag->t_flags |= cpu_to_be32(JBD2_FLAG_LAST_TAG);
635
636start_journal_io:
637 for (i = 0; i < bufs; i++) {
638 struct buffer_head *bh = wbuf[i];
639 /*
640 * Compute checksum.
641 */
642 if (JBD2_HAS_COMPAT_FEATURE(journal,
643 JBD2_FEATURE_COMPAT_CHECKSUM)) {
644 crc32_sum =
645 jbd2_checksum_data(crc32_sum, bh);
646 }
647
648 lock_buffer(bh);
649 clear_buffer_dirty(bh);
650 set_buffer_uptodate(bh);
651 bh->b_end_io = journal_end_buffer_io_sync;
652 submit_bh(WRITE_SYNC, bh);
653 }
654 cond_resched();
655 stats.run.rs_blocks_logged += bufs;
656
657 /* Force a new descriptor to be generated next
658 time round the loop. */
659 descriptor = NULL;
660 bufs = 0;
661 }
662 }
663
664 err = journal_finish_inode_data_buffers(journal, commit_transaction);
665 if (err) {
666 printk(KERN_WARNING
667 "JBD2: Detected IO errors while flushing file data "
668 "on %s\n", journal->j_devname);
669 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
670 jbd2_journal_abort(journal, err);
671 err = 0;
672 }
673
674 write_lock(&journal->j_state_lock);
675 J_ASSERT(commit_transaction->t_state == T_COMMIT);
676 commit_transaction->t_state = T_COMMIT_DFLUSH;
677 write_unlock(&journal->j_state_lock);
678 /*
679 * If the journal is not located on the file system device,
680 * then we must flush the file system device before we issue
681 * the commit record
682 */
683 if (commit_transaction->t_need_data_flush &&
684 (journal->j_fs_dev != journal->j_dev) &&
685 (journal->j_flags & JBD2_BARRIER))
686 blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
687
688 /* Done it all: now write the commit record asynchronously. */
689 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
690 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
691 err = journal_submit_commit_record(journal, commit_transaction,
692 &cbh, crc32_sum);
693 if (err)
694 __jbd2_journal_abort_hard(journal);
695 }
696
697 blk_finish_plug(&plug);
698
699 /* Lo and behold: we have just managed to send a transaction to
700 the log. Before we can commit it, wait for the IO so far to
701 complete. Control buffers being written are on the
702 transaction's t_log_list queue, and metadata buffers are on
703 the t_iobuf_list queue.
704
705 Wait for the buffers in reverse order. That way we are
706 less likely to be woken up until all IOs have completed, and
707 so we incur less scheduling load.
708 */
709
710 jbd_debug(3, "JBD: commit phase 3\n");
711
712 /*
713 * akpm: these are BJ_IO, and j_list_lock is not needed.
714 * See __journal_try_to_free_buffer.
715 */
716wait_for_iobuf:
717 while (commit_transaction->t_iobuf_list != NULL) {
718 struct buffer_head *bh;
719
720 jh = commit_transaction->t_iobuf_list->b_tprev;
721 bh = jh2bh(jh);
722 if (buffer_locked(bh)) {
723 wait_on_buffer(bh);
724 goto wait_for_iobuf;
725 }
726 if (cond_resched())
727 goto wait_for_iobuf;
728
729 if (unlikely(!buffer_uptodate(bh)))
730 err = -EIO;
731
732 clear_buffer_jwrite(bh);
733
734 JBUFFER_TRACE(jh, "ph4: unfile after journal write");
735 jbd2_journal_unfile_buffer(journal, jh);
736
737 /*
738 * ->t_iobuf_list should contain only dummy buffer_heads
739 * which were created by jbd2_journal_write_metadata_buffer().
740 */
741 BUFFER_TRACE(bh, "dumping temporary bh");
742 jbd2_journal_put_journal_head(jh);
743 __brelse(bh);
744 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
745 free_buffer_head(bh);
746
747 /* We also have to unlock and free the corresponding
748 shadowed buffer */
749 jh = commit_transaction->t_shadow_list->b_tprev;
750 bh = jh2bh(jh);
751 clear_bit(BH_JWrite, &bh->b_state);
752 J_ASSERT_BH(bh, buffer_jbddirty(bh));
753
754 /* The metadata is now released for reuse, but we need
755 to remember it against this transaction so that when
756 we finally commit, we can do any checkpointing
757 required. */
758 JBUFFER_TRACE(jh, "file as BJ_Forget");
759 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
760 /*
761 * Wake up any transactions which were waiting for this IO to
762 * complete. The barrier must be here so that changes by
763 * jbd2_journal_file_buffer() take effect before wake_up_bit()
764 * does the waitqueue check.
765 */
766 smp_mb();
767 wake_up_bit(&bh->b_state, BH_Unshadow);
768 JBUFFER_TRACE(jh, "brelse shadowed buffer");
769 __brelse(bh);
770 }
771
772 J_ASSERT (commit_transaction->t_shadow_list == NULL);
773
774 jbd_debug(3, "JBD: commit phase 4\n");
775
776 /* Here we wait for the revoke record and descriptor record buffers */
777 wait_for_ctlbuf:
778 while (commit_transaction->t_log_list != NULL) {
779 struct buffer_head *bh;
780
781 jh = commit_transaction->t_log_list->b_tprev;
782 bh = jh2bh(jh);
783 if (buffer_locked(bh)) {
784 wait_on_buffer(bh);
785 goto wait_for_ctlbuf;
786 }
787 if (cond_resched())
788 goto wait_for_ctlbuf;
789
790 if (unlikely(!buffer_uptodate(bh)))
791 err = -EIO;
792
793 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
794 clear_buffer_jwrite(bh);
795 jbd2_journal_unfile_buffer(journal, jh);
796 jbd2_journal_put_journal_head(jh);
797 __brelse(bh); /* One for getblk */
798 /* AKPM: bforget here */
799 }
800
801 if (err)
802 jbd2_journal_abort(journal, err);
803
804 jbd_debug(3, "JBD: commit phase 5\n");
805 write_lock(&journal->j_state_lock);
806 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
807 commit_transaction->t_state = T_COMMIT_JFLUSH;
808 write_unlock(&journal->j_state_lock);
809
810 if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
811 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
812 err = journal_submit_commit_record(journal, commit_transaction,
813 &cbh, crc32_sum);
814 if (err)
815 __jbd2_journal_abort_hard(journal);
816 }
817 if (cbh)
818 err = journal_wait_on_commit_record(journal, cbh);
819 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
820 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) &&
821 journal->j_flags & JBD2_BARRIER) {
822 blkdev_issue_flush(journal->j_dev, GFP_KERNEL, NULL);
823 }
824
825 if (err)
826 jbd2_journal_abort(journal, err);
827
828 /* End of a transaction! Finally, we can do checkpoint
829 processing: any buffers committed as a result of this
830 transaction can be removed from any checkpoint list it was on
831 before. */
832
833 jbd_debug(3, "JBD: commit phase 6\n");
834
835 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
836 J_ASSERT(commit_transaction->t_buffers == NULL);
837 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
838 J_ASSERT(commit_transaction->t_iobuf_list == NULL);
839 J_ASSERT(commit_transaction->t_shadow_list == NULL);
840 J_ASSERT(commit_transaction->t_log_list == NULL);
841
842restart_loop:
843 /*
844 * As there are other places (journal_unmap_buffer()) adding buffers
845 * to this list we have to be careful and hold the j_list_lock.
846 */
847 spin_lock(&journal->j_list_lock);
848 while (commit_transaction->t_forget) {
849 transaction_t *cp_transaction;
850 struct buffer_head *bh;
851 int try_to_free = 0;
852
853 jh = commit_transaction->t_forget;
854 spin_unlock(&journal->j_list_lock);
855 bh = jh2bh(jh);
856 /*
857 * Get a reference so that bh cannot be freed before we are
858 * done with it.
859 */
860 get_bh(bh);
861 jbd_lock_bh_state(bh);
862 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
863
864 /*
865 * If there is undo-protected committed data against
866 * this buffer, then we can remove it now. If it is a
867 * buffer needing such protection, the old frozen_data
868 * field now points to a committed version of the
869 * buffer, so rotate that field to the new committed
870 * data.
871 *
872 * Otherwise, we can just throw away the frozen data now.
873 *
874 * We also know that the frozen data has already fired
875 * its triggers if they exist, so we can clear that too.
876 */
877 if (jh->b_committed_data) {
878 jbd2_free(jh->b_committed_data, bh->b_size);
879 jh->b_committed_data = NULL;
880 if (jh->b_frozen_data) {
881 jh->b_committed_data = jh->b_frozen_data;
882 jh->b_frozen_data = NULL;
883 jh->b_frozen_triggers = NULL;
884 }
885 } else if (jh->b_frozen_data) {
886 jbd2_free(jh->b_frozen_data, bh->b_size);
887 jh->b_frozen_data = NULL;
888 jh->b_frozen_triggers = NULL;
889 }
890
891 spin_lock(&journal->j_list_lock);
892 cp_transaction = jh->b_cp_transaction;
893 if (cp_transaction) {
894 JBUFFER_TRACE(jh, "remove from old cp transaction");
895 cp_transaction->t_chp_stats.cs_dropped++;
896 __jbd2_journal_remove_checkpoint(jh);
897 }
898
899 /* Only re-checkpoint the buffer_head if it is marked
900 * dirty. If the buffer was added to the BJ_Forget list
901 * by jbd2_journal_forget, it may no longer be dirty and
902 * there's no point in keeping a checkpoint record for
903 * it. */
904
905 /* A buffer which has been freed while still being
906 * journaled by a previous transaction may end up still
907 * being dirty here, but we want to avoid writing back
908 * that buffer in the future after the "add to orphan"
909 * operation been committed, That's not only a performance
910 * gain, it also stops aliasing problems if the buffer is
911 * left behind for writeback and gets reallocated for another
912 * use in a different page. */
913 if (buffer_freed(bh) && !jh->b_next_transaction) {
914 clear_buffer_freed(bh);
915 clear_buffer_jbddirty(bh);
916 }
917
918 if (buffer_jbddirty(bh)) {
919 JBUFFER_TRACE(jh, "add to new checkpointing trans");
920 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
921 if (is_journal_aborted(journal))
922 clear_buffer_jbddirty(bh);
923 } else {
924 J_ASSERT_BH(bh, !buffer_dirty(bh));
925 /*
926 * The buffer on BJ_Forget list and not jbddirty means
927 * it has been freed by this transaction and hence it
928 * could not have been reallocated until this
929 * transaction has committed. *BUT* it could be
930 * reallocated once we have written all the data to
931 * disk and before we process the buffer on BJ_Forget
932 * list.
933 */
934 if (!jh->b_next_transaction)
935 try_to_free = 1;
936 }
937 JBUFFER_TRACE(jh, "refile or unfile buffer");
938 __jbd2_journal_refile_buffer(jh);
939 jbd_unlock_bh_state(bh);
940 if (try_to_free)
941 release_buffer_page(bh); /* Drops bh reference */
942 else
943 __brelse(bh);
944 cond_resched_lock(&journal->j_list_lock);
945 }
946 spin_unlock(&journal->j_list_lock);
947 /*
948 * This is a bit sleazy. We use j_list_lock to protect transition
949 * of a transaction into T_FINISHED state and calling
950 * __jbd2_journal_drop_transaction(). Otherwise we could race with
951 * other checkpointing code processing the transaction...
952 */
953 write_lock(&journal->j_state_lock);
954 spin_lock(&journal->j_list_lock);
955 /*
956 * Now recheck if some buffers did not get attached to the transaction
957 * while the lock was dropped...
958 */
959 if (commit_transaction->t_forget) {
960 spin_unlock(&journal->j_list_lock);
961 write_unlock(&journal->j_state_lock);
962 goto restart_loop;
963 }
964
965 /* Done with this transaction! */
966
967 jbd_debug(3, "JBD: commit phase 7\n");
968
969 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
970
971 commit_transaction->t_start = jiffies;
972 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
973 commit_transaction->t_start);
974
975 /*
976 * File the transaction statistics
977 */
978 stats.ts_tid = commit_transaction->t_tid;
979 stats.run.rs_handle_count =
980 atomic_read(&commit_transaction->t_handle_count);
981 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
982 commit_transaction->t_tid, &stats.run);
983
984 /*
985 * Calculate overall stats
986 */
987 spin_lock(&journal->j_history_lock);
988 journal->j_stats.ts_tid++;
989 journal->j_stats.run.rs_wait += stats.run.rs_wait;
990 journal->j_stats.run.rs_running += stats.run.rs_running;
991 journal->j_stats.run.rs_locked += stats.run.rs_locked;
992 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
993 journal->j_stats.run.rs_logging += stats.run.rs_logging;
994 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
995 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
996 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
997 spin_unlock(&journal->j_history_lock);
998
999 commit_transaction->t_state = T_FINISHED;
1000 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1001 journal->j_commit_sequence = commit_transaction->t_tid;
1002 journal->j_committing_transaction = NULL;
1003 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1004
1005 /*
1006 * weight the commit time higher than the average time so we don't
1007 * react too strongly to vast changes in the commit time
1008 */
1009 if (likely(journal->j_average_commit_time))
1010 journal->j_average_commit_time = (commit_time +
1011 journal->j_average_commit_time*3) / 4;
1012 else
1013 journal->j_average_commit_time = commit_time;
1014 write_unlock(&journal->j_state_lock);
1015
1016 if (commit_transaction->t_checkpoint_list == NULL &&
1017 commit_transaction->t_checkpoint_io_list == NULL) {
1018 __jbd2_journal_drop_transaction(journal, commit_transaction);
1019 to_free = 1;
1020 } else {
1021 if (journal->j_checkpoint_transactions == NULL) {
1022 journal->j_checkpoint_transactions = commit_transaction;
1023 commit_transaction->t_cpnext = commit_transaction;
1024 commit_transaction->t_cpprev = commit_transaction;
1025 } else {
1026 commit_transaction->t_cpnext =
1027 journal->j_checkpoint_transactions;
1028 commit_transaction->t_cpprev =
1029 commit_transaction->t_cpnext->t_cpprev;
1030 commit_transaction->t_cpnext->t_cpprev =
1031 commit_transaction;
1032 commit_transaction->t_cpprev->t_cpnext =
1033 commit_transaction;
1034 }
1035 }
1036 spin_unlock(&journal->j_list_lock);
1037
1038 if (journal->j_commit_callback)
1039 journal->j_commit_callback(journal, commit_transaction);
1040
1041 trace_jbd2_end_commit(journal, commit_transaction);
1042 jbd_debug(1, "JBD: commit %d complete, head %d\n",
1043 journal->j_commit_sequence, journal->j_tail_sequence);
1044 if (to_free)
1045 kfree(commit_transaction);
1046
1047 wake_up(&journal->j_wait_done_commit);
1048}
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}