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