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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * linux/fs/jbd2/commit.c
4 *
5 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
6 *
7 * Copyright 1998 Red Hat corp --- All Rights Reserved
8 *
9 * Journal commit routines for the generic filesystem journaling code;
10 * part of the ext2fs journaling system.
11 */
12
13#include <linux/time.h>
14#include <linux/fs.h>
15#include <linux/jbd2.h>
16#include <linux/errno.h>
17#include <linux/slab.h>
18#include <linux/mm.h>
19#include <linux/pagemap.h>
20#include <linux/jiffies.h>
21#include <linux/crc32.h>
22#include <linux/writeback.h>
23#include <linux/backing-dev.h>
24#include <linux/bio.h>
25#include <linux/blkdev.h>
26#include <linux/bitops.h>
27#include <trace/events/jbd2.h>
28
29/*
30 * IO end handler for temporary buffer_heads handling writes to the journal.
31 */
32static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
33{
34 struct buffer_head *orig_bh = bh->b_private;
35
36 BUFFER_TRACE(bh, "");
37 if (uptodate)
38 set_buffer_uptodate(bh);
39 else
40 clear_buffer_uptodate(bh);
41 if (orig_bh) {
42 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
43 smp_mb__after_atomic();
44 wake_up_bit(&orig_bh->b_state, BH_Shadow);
45 }
46 unlock_buffer(bh);
47}
48
49/*
50 * When an ext4 file is truncated, it is possible that some pages are not
51 * successfully freed, because they are attached to a committing transaction.
52 * After the transaction commits, these pages are left on the LRU, with no
53 * ->mapping, and with attached buffers. These pages are trivially reclaimable
54 * by the VM, but their apparent absence upsets the VM accounting, and it makes
55 * the numbers in /proc/meminfo look odd.
56 *
57 * So here, we have a buffer which has just come off the forget list. Look to
58 * see if we can strip all buffers from the backing page.
59 *
60 * Called under lock_journal(), and possibly under journal_datalist_lock. The
61 * caller provided us with a ref against the buffer, and we drop that here.
62 */
63static void release_buffer_page(struct buffer_head *bh)
64{
65 struct folio *folio;
66 struct page *page;
67
68 if (buffer_dirty(bh))
69 goto nope;
70 if (atomic_read(&bh->b_count) != 1)
71 goto nope;
72 page = bh->b_page;
73 if (!page)
74 goto nope;
75 folio = page_folio(page);
76 if (folio->mapping)
77 goto nope;
78
79 /* OK, it's a truncated page */
80 if (!folio_trylock(folio))
81 goto nope;
82
83 folio_get(folio);
84 __brelse(bh);
85 try_to_free_buffers(folio);
86 folio_unlock(folio);
87 folio_put(folio);
88 return;
89
90nope:
91 __brelse(bh);
92}
93
94static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
95{
96 struct commit_header *h;
97 __u32 csum;
98
99 if (!jbd2_journal_has_csum_v2or3(j))
100 return;
101
102 h = (struct commit_header *)(bh->b_data);
103 h->h_chksum_type = 0;
104 h->h_chksum_size = 0;
105 h->h_chksum[0] = 0;
106 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
107 h->h_chksum[0] = cpu_to_be32(csum);
108}
109
110/*
111 * Done it all: now submit the commit record. We should have
112 * cleaned up our previous buffers by now, so if we are in abort
113 * mode we can now just skip the rest of the journal write
114 * entirely.
115 *
116 * Returns 1 if the journal needs to be aborted or 0 on success
117 */
118static int journal_submit_commit_record(journal_t *journal,
119 transaction_t *commit_transaction,
120 struct buffer_head **cbh,
121 __u32 crc32_sum)
122{
123 struct commit_header *tmp;
124 struct buffer_head *bh;
125 struct timespec64 now;
126 blk_opf_t write_flags = REQ_OP_WRITE | REQ_SYNC;
127
128 *cbh = NULL;
129
130 if (is_journal_aborted(journal))
131 return 0;
132
133 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
134 JBD2_COMMIT_BLOCK);
135 if (!bh)
136 return 1;
137
138 tmp = (struct commit_header *)bh->b_data;
139 ktime_get_coarse_real_ts64(&now);
140 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
141 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
142
143 if (jbd2_has_feature_checksum(journal)) {
144 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
145 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
146 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
147 }
148 jbd2_commit_block_csum_set(journal, bh);
149
150 BUFFER_TRACE(bh, "submit commit block");
151 lock_buffer(bh);
152 clear_buffer_dirty(bh);
153 set_buffer_uptodate(bh);
154 bh->b_end_io = journal_end_buffer_io_sync;
155
156 if (journal->j_flags & JBD2_BARRIER &&
157 !jbd2_has_feature_async_commit(journal))
158 write_flags |= REQ_PREFLUSH | REQ_FUA;
159
160 submit_bh(write_flags, bh);
161 *cbh = bh;
162 return 0;
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(journal_t *journal, struct jbd2_inode *jinode)
211{
212 if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
213 return 0;
214
215 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
216 return journal->j_submit_inode_data_buffers(jinode);
217
218}
219EXPORT_SYMBOL(jbd2_submit_inode_data);
220
221int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
222{
223 if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
224 !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
225 return 0;
226 return filemap_fdatawait_range_keep_errors(
227 jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
228 jinode->i_dirty_end);
229}
230EXPORT_SYMBOL(jbd2_wait_inode_data);
231
232/*
233 * Submit all the data buffers of inode associated with the transaction to
234 * disk.
235 *
236 * We are in a committing transaction. Therefore no new inode can be added to
237 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
238 * operate on from being released while we write out pages.
239 */
240static int journal_submit_data_buffers(journal_t *journal,
241 transaction_t *commit_transaction)
242{
243 struct jbd2_inode *jinode;
244 int err, ret = 0;
245
246 spin_lock(&journal->j_list_lock);
247 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
248 if (!(jinode->i_flags & JI_WRITE_DATA))
249 continue;
250 jinode->i_flags |= JI_COMMIT_RUNNING;
251 spin_unlock(&journal->j_list_lock);
252 /* submit the inode data buffers. */
253 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
254 if (journal->j_submit_inode_data_buffers) {
255 err = journal->j_submit_inode_data_buffers(jinode);
256 if (!ret)
257 ret = err;
258 }
259 spin_lock(&journal->j_list_lock);
260 J_ASSERT(jinode->i_transaction == commit_transaction);
261 jinode->i_flags &= ~JI_COMMIT_RUNNING;
262 smp_mb();
263 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
264 }
265 spin_unlock(&journal->j_list_lock);
266 return ret;
267}
268
269int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
270{
271 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
272
273 return filemap_fdatawait_range_keep_errors(mapping,
274 jinode->i_dirty_start,
275 jinode->i_dirty_end);
276}
277
278/*
279 * Wait for data submitted for writeout, refile inodes to proper
280 * transaction if needed.
281 *
282 */
283static int journal_finish_inode_data_buffers(journal_t *journal,
284 transaction_t *commit_transaction)
285{
286 struct jbd2_inode *jinode, *next_i;
287 int err, ret = 0;
288
289 /* For locking, see the comment in journal_submit_data_buffers() */
290 spin_lock(&journal->j_list_lock);
291 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
292 if (!(jinode->i_flags & JI_WAIT_DATA))
293 continue;
294 jinode->i_flags |= JI_COMMIT_RUNNING;
295 spin_unlock(&journal->j_list_lock);
296 /* wait for the inode data buffers writeout. */
297 if (journal->j_finish_inode_data_buffers) {
298 err = journal->j_finish_inode_data_buffers(jinode);
299 if (!ret)
300 ret = err;
301 }
302 spin_lock(&journal->j_list_lock);
303 jinode->i_flags &= ~JI_COMMIT_RUNNING;
304 smp_mb();
305 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
306 }
307
308 /* Now refile inode to proper lists */
309 list_for_each_entry_safe(jinode, next_i,
310 &commit_transaction->t_inode_list, i_list) {
311 list_del(&jinode->i_list);
312 if (jinode->i_next_transaction) {
313 jinode->i_transaction = jinode->i_next_transaction;
314 jinode->i_next_transaction = NULL;
315 list_add(&jinode->i_list,
316 &jinode->i_transaction->t_inode_list);
317 } else {
318 jinode->i_transaction = NULL;
319 jinode->i_dirty_start = 0;
320 jinode->i_dirty_end = 0;
321 }
322 }
323 spin_unlock(&journal->j_list_lock);
324
325 return ret;
326}
327
328static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
329{
330 struct page *page = bh->b_page;
331 char *addr;
332 __u32 checksum;
333
334 addr = kmap_atomic(page);
335 checksum = crc32_be(crc32_sum,
336 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
337 kunmap_atomic(addr);
338
339 return checksum;
340}
341
342static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
343 unsigned long long block)
344{
345 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
346 if (jbd2_has_feature_64bit(j))
347 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
348}
349
350static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
351 struct buffer_head *bh, __u32 sequence)
352{
353 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
354 struct page *page = bh->b_page;
355 __u8 *addr;
356 __u32 csum32;
357 __be32 seq;
358
359 if (!jbd2_journal_has_csum_v2or3(j))
360 return;
361
362 seq = cpu_to_be32(sequence);
363 addr = kmap_atomic(page);
364 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
365 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
366 bh->b_size);
367 kunmap_atomic(addr);
368
369 if (jbd2_has_feature_csum3(j))
370 tag3->t_checksum = cpu_to_be32(csum32);
371 else
372 tag->t_checksum = cpu_to_be16(csum32);
373}
374/*
375 * jbd2_journal_commit_transaction
376 *
377 * The primary function for committing a transaction to the log. This
378 * function is called by the journal thread to begin a complete commit.
379 */
380void jbd2_journal_commit_transaction(journal_t *journal)
381{
382 struct transaction_stats_s stats;
383 transaction_t *commit_transaction;
384 struct journal_head *jh;
385 struct buffer_head *descriptor;
386 struct buffer_head **wbuf = journal->j_wbuf;
387 int bufs;
388 int flags;
389 int err;
390 unsigned long long blocknr;
391 ktime_t start_time;
392 u64 commit_time;
393 char *tagp = NULL;
394 journal_block_tag_t *tag = NULL;
395 int space_left = 0;
396 int first_tag = 0;
397 int tag_flag;
398 int i;
399 int tag_bytes = journal_tag_bytes(journal);
400 struct buffer_head *cbh = NULL; /* For transactional checksums */
401 __u32 crc32_sum = ~0;
402 struct blk_plug plug;
403 /* Tail of the journal */
404 unsigned long first_block;
405 tid_t first_tid;
406 int update_tail;
407 int csum_size = 0;
408 LIST_HEAD(io_bufs);
409 LIST_HEAD(log_bufs);
410
411 if (jbd2_journal_has_csum_v2or3(journal))
412 csum_size = sizeof(struct jbd2_journal_block_tail);
413
414 /*
415 * First job: lock down the current transaction and wait for
416 * all outstanding updates to complete.
417 */
418
419 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
420 if (journal->j_flags & JBD2_FLUSHED) {
421 jbd2_debug(3, "super block updated\n");
422 mutex_lock_io(&journal->j_checkpoint_mutex);
423 /*
424 * We hold j_checkpoint_mutex so tail cannot change under us.
425 * We don't need any special data guarantees for writing sb
426 * since journal is empty and it is ok for write to be
427 * flushed only with transaction commit.
428 */
429 jbd2_journal_update_sb_log_tail(journal,
430 journal->j_tail_sequence,
431 journal->j_tail,
432 REQ_SYNC);
433 mutex_unlock(&journal->j_checkpoint_mutex);
434 } else {
435 jbd2_debug(3, "superblock not updated\n");
436 }
437
438 J_ASSERT(journal->j_running_transaction != NULL);
439 J_ASSERT(journal->j_committing_transaction == NULL);
440
441 write_lock(&journal->j_state_lock);
442 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
443 while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
444 DEFINE_WAIT(wait);
445
446 prepare_to_wait(&journal->j_fc_wait, &wait,
447 TASK_UNINTERRUPTIBLE);
448 write_unlock(&journal->j_state_lock);
449 schedule();
450 write_lock(&journal->j_state_lock);
451 finish_wait(&journal->j_fc_wait, &wait);
452 /*
453 * TODO: by blocking fast commits here, we are increasing
454 * fsync() latency slightly. Strictly speaking, we don't need
455 * to block fast commits until the transaction enters T_FLUSH
456 * state. So an optimization is possible where we block new fast
457 * commits here and wait for existing ones to complete
458 * just before we enter T_FLUSH. That way, the existing fast
459 * commits and this full commit can proceed parallely.
460 */
461 }
462 write_unlock(&journal->j_state_lock);
463
464 commit_transaction = journal->j_running_transaction;
465
466 trace_jbd2_start_commit(journal, commit_transaction);
467 jbd2_debug(1, "JBD2: starting commit of transaction %d\n",
468 commit_transaction->t_tid);
469
470 write_lock(&journal->j_state_lock);
471 journal->j_fc_off = 0;
472 J_ASSERT(commit_transaction->t_state == T_RUNNING);
473 commit_transaction->t_state = T_LOCKED;
474
475 trace_jbd2_commit_locking(journal, commit_transaction);
476 stats.run.rs_wait = commit_transaction->t_max_wait;
477 stats.run.rs_request_delay = 0;
478 stats.run.rs_locked = jiffies;
479 if (commit_transaction->t_requested)
480 stats.run.rs_request_delay =
481 jbd2_time_diff(commit_transaction->t_requested,
482 stats.run.rs_locked);
483 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
484 stats.run.rs_locked);
485
486 // waits for any t_updates to finish
487 jbd2_journal_wait_updates(journal);
488
489 commit_transaction->t_state = T_SWITCH;
490
491 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
492 journal->j_max_transaction_buffers);
493
494 /*
495 * First thing we are allowed to do is to discard any remaining
496 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
497 * that there are no such buffers: if a large filesystem
498 * operation like a truncate needs to split itself over multiple
499 * transactions, then it may try to do a jbd2_journal_restart() while
500 * there are still BJ_Reserved buffers outstanding. These must
501 * be released cleanly from the current transaction.
502 *
503 * In this case, the filesystem must still reserve write access
504 * again before modifying the buffer in the new transaction, but
505 * we do not require it to remember exactly which old buffers it
506 * has reserved. This is consistent with the existing behaviour
507 * that multiple jbd2_journal_get_write_access() calls to the same
508 * buffer are perfectly permissible.
509 * We use journal->j_state_lock here to serialize processing of
510 * t_reserved_list with eviction of buffers from journal_unmap_buffer().
511 */
512 while (commit_transaction->t_reserved_list) {
513 jh = commit_transaction->t_reserved_list;
514 JBUFFER_TRACE(jh, "reserved, unused: refile");
515 /*
516 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
517 * leave undo-committed data.
518 */
519 if (jh->b_committed_data) {
520 struct buffer_head *bh = jh2bh(jh);
521
522 spin_lock(&jh->b_state_lock);
523 jbd2_free(jh->b_committed_data, bh->b_size);
524 jh->b_committed_data = NULL;
525 spin_unlock(&jh->b_state_lock);
526 }
527 jbd2_journal_refile_buffer(journal, jh);
528 }
529
530 write_unlock(&journal->j_state_lock);
531 /*
532 * Now try to drop any written-back buffers from the journal's
533 * checkpoint lists. We do this *before* commit because it potentially
534 * frees some memory
535 */
536 spin_lock(&journal->j_list_lock);
537 __jbd2_journal_clean_checkpoint_list(journal, false);
538 spin_unlock(&journal->j_list_lock);
539
540 jbd2_debug(3, "JBD2: commit phase 1\n");
541
542 /*
543 * Clear revoked flag to reflect there is no revoked buffers
544 * in the next transaction which is going to be started.
545 */
546 jbd2_clear_buffer_revoked_flags(journal);
547
548 /*
549 * Switch to a new revoke table.
550 */
551 jbd2_journal_switch_revoke_table(journal);
552
553 write_lock(&journal->j_state_lock);
554 /*
555 * Reserved credits cannot be claimed anymore, free them
556 */
557 atomic_sub(atomic_read(&journal->j_reserved_credits),
558 &commit_transaction->t_outstanding_credits);
559
560 trace_jbd2_commit_flushing(journal, commit_transaction);
561 stats.run.rs_flushing = jiffies;
562 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
563 stats.run.rs_flushing);
564
565 commit_transaction->t_state = T_FLUSH;
566 journal->j_committing_transaction = commit_transaction;
567 journal->j_running_transaction = NULL;
568 start_time = ktime_get();
569 commit_transaction->t_log_start = journal->j_head;
570 wake_up_all(&journal->j_wait_transaction_locked);
571 write_unlock(&journal->j_state_lock);
572
573 jbd2_debug(3, "JBD2: commit phase 2a\n");
574
575 /*
576 * Now start flushing things to disk, in the order they appear
577 * on the transaction lists. Data blocks go first.
578 */
579 err = journal_submit_data_buffers(journal, commit_transaction);
580 if (err)
581 jbd2_journal_abort(journal, err);
582
583 blk_start_plug(&plug);
584 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
585
586 jbd2_debug(3, "JBD2: commit phase 2b\n");
587
588 /*
589 * Way to go: we have now written out all of the data for a
590 * transaction! Now comes the tricky part: we need to write out
591 * metadata. Loop over the transaction's entire buffer list:
592 */
593 write_lock(&journal->j_state_lock);
594 commit_transaction->t_state = T_COMMIT;
595 write_unlock(&journal->j_state_lock);
596
597 trace_jbd2_commit_logging(journal, commit_transaction);
598 stats.run.rs_logging = jiffies;
599 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
600 stats.run.rs_logging);
601 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
602 stats.run.rs_blocks_logged = 0;
603
604 J_ASSERT(commit_transaction->t_nr_buffers <=
605 atomic_read(&commit_transaction->t_outstanding_credits));
606
607 err = 0;
608 bufs = 0;
609 descriptor = NULL;
610 while (commit_transaction->t_buffers) {
611
612 /* Find the next buffer to be journaled... */
613
614 jh = commit_transaction->t_buffers;
615
616 /* If we're in abort mode, we just un-journal the buffer and
617 release it. */
618
619 if (is_journal_aborted(journal)) {
620 clear_buffer_jbddirty(jh2bh(jh));
621 JBUFFER_TRACE(jh, "journal is aborting: refile");
622 jbd2_buffer_abort_trigger(jh,
623 jh->b_frozen_data ?
624 jh->b_frozen_triggers :
625 jh->b_triggers);
626 jbd2_journal_refile_buffer(journal, jh);
627 /* If that was the last one, we need to clean up
628 * any descriptor buffers which may have been
629 * already allocated, even if we are now
630 * aborting. */
631 if (!commit_transaction->t_buffers)
632 goto start_journal_io;
633 continue;
634 }
635
636 /* Make sure we have a descriptor block in which to
637 record the metadata buffer. */
638
639 if (!descriptor) {
640 J_ASSERT (bufs == 0);
641
642 jbd2_debug(4, "JBD2: get descriptor\n");
643
644 descriptor = jbd2_journal_get_descriptor_buffer(
645 commit_transaction,
646 JBD2_DESCRIPTOR_BLOCK);
647 if (!descriptor) {
648 jbd2_journal_abort(journal, -EIO);
649 continue;
650 }
651
652 jbd2_debug(4, "JBD2: got buffer %llu (%p)\n",
653 (unsigned long long)descriptor->b_blocknr,
654 descriptor->b_data);
655 tagp = &descriptor->b_data[sizeof(journal_header_t)];
656 space_left = descriptor->b_size -
657 sizeof(journal_header_t);
658 first_tag = 1;
659 set_buffer_jwrite(descriptor);
660 set_buffer_dirty(descriptor);
661 wbuf[bufs++] = descriptor;
662
663 /* Record it so that we can wait for IO
664 completion later */
665 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
666 jbd2_file_log_bh(&log_bufs, descriptor);
667 }
668
669 /* Where is the buffer to be written? */
670
671 err = jbd2_journal_next_log_block(journal, &blocknr);
672 /* If the block mapping failed, just abandon the buffer
673 and repeat this loop: we'll fall into the
674 refile-on-abort condition above. */
675 if (err) {
676 jbd2_journal_abort(journal, err);
677 continue;
678 }
679
680 /*
681 * start_this_handle() uses t_outstanding_credits to determine
682 * the free space in the log.
683 */
684 atomic_dec(&commit_transaction->t_outstanding_credits);
685
686 /* Bump b_count to prevent truncate from stumbling over
687 the shadowed buffer! @@@ This can go if we ever get
688 rid of the shadow pairing of buffers. */
689 atomic_inc(&jh2bh(jh)->b_count);
690
691 /*
692 * Make a temporary IO buffer with which to write it out
693 * (this will requeue the metadata buffer to BJ_Shadow).
694 */
695 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
696 JBUFFER_TRACE(jh, "ph3: write metadata");
697 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
698 jh, &wbuf[bufs], blocknr);
699 if (flags < 0) {
700 jbd2_journal_abort(journal, flags);
701 continue;
702 }
703 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
704
705 /* Record the new block's tag in the current descriptor
706 buffer */
707
708 tag_flag = 0;
709 if (flags & 1)
710 tag_flag |= JBD2_FLAG_ESCAPE;
711 if (!first_tag)
712 tag_flag |= JBD2_FLAG_SAME_UUID;
713
714 tag = (journal_block_tag_t *) tagp;
715 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
716 tag->t_flags = cpu_to_be16(tag_flag);
717 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
718 commit_transaction->t_tid);
719 tagp += tag_bytes;
720 space_left -= tag_bytes;
721 bufs++;
722
723 if (first_tag) {
724 memcpy (tagp, journal->j_uuid, 16);
725 tagp += 16;
726 space_left -= 16;
727 first_tag = 0;
728 }
729
730 /* If there's no more to do, or if the descriptor is full,
731 let the IO rip! */
732
733 if (bufs == journal->j_wbufsize ||
734 commit_transaction->t_buffers == NULL ||
735 space_left < tag_bytes + 16 + csum_size) {
736
737 jbd2_debug(4, "JBD2: Submit %d IOs\n", bufs);
738
739 /* Write an end-of-descriptor marker before
740 submitting the IOs. "tag" still points to
741 the last tag we set up. */
742
743 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
744start_journal_io:
745 if (descriptor)
746 jbd2_descriptor_block_csum_set(journal,
747 descriptor);
748
749 for (i = 0; i < bufs; i++) {
750 struct buffer_head *bh = wbuf[i];
751 /*
752 * Compute checksum.
753 */
754 if (jbd2_has_feature_checksum(journal)) {
755 crc32_sum =
756 jbd2_checksum_data(crc32_sum, bh);
757 }
758
759 lock_buffer(bh);
760 clear_buffer_dirty(bh);
761 set_buffer_uptodate(bh);
762 bh->b_end_io = journal_end_buffer_io_sync;
763 submit_bh(REQ_OP_WRITE | REQ_SYNC, bh);
764 }
765 cond_resched();
766
767 /* Force a new descriptor to be generated next
768 time round the loop. */
769 descriptor = NULL;
770 bufs = 0;
771 }
772 }
773
774 err = journal_finish_inode_data_buffers(journal, commit_transaction);
775 if (err) {
776 printk(KERN_WARNING
777 "JBD2: Detected IO errors while flushing file data "
778 "on %s\n", journal->j_devname);
779 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
780 jbd2_journal_abort(journal, err);
781 err = 0;
782 }
783
784 /*
785 * Get current oldest transaction in the log before we issue flush
786 * to the filesystem device. After the flush we can be sure that
787 * blocks of all older transactions are checkpointed to persistent
788 * storage and we will be safe to update journal start in the
789 * superblock with the numbers we get here.
790 */
791 update_tail =
792 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
793
794 write_lock(&journal->j_state_lock);
795 if (update_tail) {
796 long freed = first_block - journal->j_tail;
797
798 if (first_block < journal->j_tail)
799 freed += journal->j_last - journal->j_first;
800 /* Update tail only if we free significant amount of space */
801 if (freed < jbd2_journal_get_max_txn_bufs(journal))
802 update_tail = 0;
803 }
804 J_ASSERT(commit_transaction->t_state == T_COMMIT);
805 commit_transaction->t_state = T_COMMIT_DFLUSH;
806 write_unlock(&journal->j_state_lock);
807
808 /*
809 * If the journal is not located on the file system device,
810 * then we must flush the file system device before we issue
811 * the commit record
812 */
813 if (commit_transaction->t_need_data_flush &&
814 (journal->j_fs_dev != journal->j_dev) &&
815 (journal->j_flags & JBD2_BARRIER))
816 blkdev_issue_flush(journal->j_fs_dev);
817
818 /* Done it all: now write the commit record asynchronously. */
819 if (jbd2_has_feature_async_commit(journal)) {
820 err = journal_submit_commit_record(journal, commit_transaction,
821 &cbh, crc32_sum);
822 if (err)
823 jbd2_journal_abort(journal, err);
824 }
825
826 blk_finish_plug(&plug);
827
828 /* Lo and behold: we have just managed to send a transaction to
829 the log. Before we can commit it, wait for the IO so far to
830 complete. Control buffers being written are on the
831 transaction's t_log_list queue, and metadata buffers are on
832 the io_bufs list.
833
834 Wait for the buffers in reverse order. That way we are
835 less likely to be woken up until all IOs have completed, and
836 so we incur less scheduling load.
837 */
838
839 jbd2_debug(3, "JBD2: commit phase 3\n");
840
841 while (!list_empty(&io_bufs)) {
842 struct buffer_head *bh = list_entry(io_bufs.prev,
843 struct buffer_head,
844 b_assoc_buffers);
845
846 wait_on_buffer(bh);
847 cond_resched();
848
849 if (unlikely(!buffer_uptodate(bh)))
850 err = -EIO;
851 jbd2_unfile_log_bh(bh);
852 stats.run.rs_blocks_logged++;
853
854 /*
855 * The list contains temporary buffer heads created by
856 * jbd2_journal_write_metadata_buffer().
857 */
858 BUFFER_TRACE(bh, "dumping temporary bh");
859 __brelse(bh);
860 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
861 free_buffer_head(bh);
862
863 /* We also have to refile the corresponding shadowed buffer */
864 jh = commit_transaction->t_shadow_list->b_tprev;
865 bh = jh2bh(jh);
866 clear_buffer_jwrite(bh);
867 J_ASSERT_BH(bh, buffer_jbddirty(bh));
868 J_ASSERT_BH(bh, !buffer_shadow(bh));
869
870 /* The metadata is now released for reuse, but we need
871 to remember it against this transaction so that when
872 we finally commit, we can do any checkpointing
873 required. */
874 JBUFFER_TRACE(jh, "file as BJ_Forget");
875 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
876 JBUFFER_TRACE(jh, "brelse shadowed buffer");
877 __brelse(bh);
878 }
879
880 J_ASSERT (commit_transaction->t_shadow_list == NULL);
881
882 jbd2_debug(3, "JBD2: commit phase 4\n");
883
884 /* Here we wait for the revoke record and descriptor record buffers */
885 while (!list_empty(&log_bufs)) {
886 struct buffer_head *bh;
887
888 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
889 wait_on_buffer(bh);
890 cond_resched();
891
892 if (unlikely(!buffer_uptodate(bh)))
893 err = -EIO;
894
895 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
896 clear_buffer_jwrite(bh);
897 jbd2_unfile_log_bh(bh);
898 stats.run.rs_blocks_logged++;
899 __brelse(bh); /* One for getblk */
900 /* AKPM: bforget here */
901 }
902
903 if (err)
904 jbd2_journal_abort(journal, err);
905
906 jbd2_debug(3, "JBD2: commit phase 5\n");
907 write_lock(&journal->j_state_lock);
908 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
909 commit_transaction->t_state = T_COMMIT_JFLUSH;
910 write_unlock(&journal->j_state_lock);
911
912 if (!jbd2_has_feature_async_commit(journal)) {
913 err = journal_submit_commit_record(journal, commit_transaction,
914 &cbh, crc32_sum);
915 if (err)
916 jbd2_journal_abort(journal, err);
917 }
918 if (cbh)
919 err = journal_wait_on_commit_record(journal, cbh);
920 stats.run.rs_blocks_logged++;
921 if (jbd2_has_feature_async_commit(journal) &&
922 journal->j_flags & JBD2_BARRIER) {
923 blkdev_issue_flush(journal->j_dev);
924 }
925
926 if (err)
927 jbd2_journal_abort(journal, err);
928
929 WARN_ON_ONCE(
930 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
931
932 /*
933 * Now disk caches for filesystem device are flushed so we are safe to
934 * erase checkpointed transactions from the log by updating journal
935 * superblock.
936 */
937 if (update_tail)
938 jbd2_update_log_tail(journal, first_tid, first_block);
939
940 /* End of a transaction! Finally, we can do checkpoint
941 processing: any buffers committed as a result of this
942 transaction can be removed from any checkpoint list it was on
943 before. */
944
945 jbd2_debug(3, "JBD2: commit phase 6\n");
946
947 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
948 J_ASSERT(commit_transaction->t_buffers == NULL);
949 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
950 J_ASSERT(commit_transaction->t_shadow_list == NULL);
951
952restart_loop:
953 /*
954 * As there are other places (journal_unmap_buffer()) adding buffers
955 * to this list we have to be careful and hold the j_list_lock.
956 */
957 spin_lock(&journal->j_list_lock);
958 while (commit_transaction->t_forget) {
959 transaction_t *cp_transaction;
960 struct buffer_head *bh;
961 int try_to_free = 0;
962 bool drop_ref;
963
964 jh = commit_transaction->t_forget;
965 spin_unlock(&journal->j_list_lock);
966 bh = jh2bh(jh);
967 /*
968 * Get a reference so that bh cannot be freed before we are
969 * done with it.
970 */
971 get_bh(bh);
972 spin_lock(&jh->b_state_lock);
973 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
974
975 /*
976 * If there is undo-protected committed data against
977 * this buffer, then we can remove it now. If it is a
978 * buffer needing such protection, the old frozen_data
979 * field now points to a committed version of the
980 * buffer, so rotate that field to the new committed
981 * data.
982 *
983 * Otherwise, we can just throw away the frozen data now.
984 *
985 * We also know that the frozen data has already fired
986 * its triggers if they exist, so we can clear that too.
987 */
988 if (jh->b_committed_data) {
989 jbd2_free(jh->b_committed_data, bh->b_size);
990 jh->b_committed_data = NULL;
991 if (jh->b_frozen_data) {
992 jh->b_committed_data = jh->b_frozen_data;
993 jh->b_frozen_data = NULL;
994 jh->b_frozen_triggers = NULL;
995 }
996 } else if (jh->b_frozen_data) {
997 jbd2_free(jh->b_frozen_data, bh->b_size);
998 jh->b_frozen_data = NULL;
999 jh->b_frozen_triggers = NULL;
1000 }
1001
1002 spin_lock(&journal->j_list_lock);
1003 cp_transaction = jh->b_cp_transaction;
1004 if (cp_transaction) {
1005 JBUFFER_TRACE(jh, "remove from old cp transaction");
1006 cp_transaction->t_chp_stats.cs_dropped++;
1007 __jbd2_journal_remove_checkpoint(jh);
1008 }
1009
1010 /* Only re-checkpoint the buffer_head if it is marked
1011 * dirty. If the buffer was added to the BJ_Forget list
1012 * by jbd2_journal_forget, it may no longer be dirty and
1013 * there's no point in keeping a checkpoint record for
1014 * it. */
1015
1016 /*
1017 * A buffer which has been freed while still being journaled
1018 * by a previous transaction, refile the buffer to BJ_Forget of
1019 * the running transaction. If the just committed transaction
1020 * contains "add to orphan" operation, we can completely
1021 * invalidate the buffer now. We are rather through in that
1022 * since the buffer may be still accessible when blocksize <
1023 * pagesize and it is attached to the last partial page.
1024 */
1025 if (buffer_freed(bh) && !jh->b_next_transaction) {
1026 struct address_space *mapping;
1027
1028 clear_buffer_freed(bh);
1029 clear_buffer_jbddirty(bh);
1030
1031 /*
1032 * Block device buffers need to stay mapped all the
1033 * time, so it is enough to clear buffer_jbddirty and
1034 * buffer_freed bits. For the file mapping buffers (i.e.
1035 * journalled data) we need to unmap buffer and clear
1036 * more bits. We also need to be careful about the check
1037 * because the data page mapping can get cleared under
1038 * our hands. Note that if mapping == NULL, we don't
1039 * need to make buffer unmapped because the page is
1040 * already detached from the mapping and buffers cannot
1041 * get reused.
1042 */
1043 mapping = READ_ONCE(bh->b_page->mapping);
1044 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1045 clear_buffer_mapped(bh);
1046 clear_buffer_new(bh);
1047 clear_buffer_req(bh);
1048 bh->b_bdev = NULL;
1049 }
1050 }
1051
1052 if (buffer_jbddirty(bh)) {
1053 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1054 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1055 if (is_journal_aborted(journal))
1056 clear_buffer_jbddirty(bh);
1057 } else {
1058 J_ASSERT_BH(bh, !buffer_dirty(bh));
1059 /*
1060 * The buffer on BJ_Forget list and not jbddirty means
1061 * it has been freed by this transaction and hence it
1062 * could not have been reallocated until this
1063 * transaction has committed. *BUT* it could be
1064 * reallocated once we have written all the data to
1065 * disk and before we process the buffer on BJ_Forget
1066 * list.
1067 */
1068 if (!jh->b_next_transaction)
1069 try_to_free = 1;
1070 }
1071 JBUFFER_TRACE(jh, "refile or unfile buffer");
1072 drop_ref = __jbd2_journal_refile_buffer(jh);
1073 spin_unlock(&jh->b_state_lock);
1074 if (drop_ref)
1075 jbd2_journal_put_journal_head(jh);
1076 if (try_to_free)
1077 release_buffer_page(bh); /* Drops bh reference */
1078 else
1079 __brelse(bh);
1080 cond_resched_lock(&journal->j_list_lock);
1081 }
1082 spin_unlock(&journal->j_list_lock);
1083 /*
1084 * This is a bit sleazy. We use j_list_lock to protect transition
1085 * of a transaction into T_FINISHED state and calling
1086 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1087 * other checkpointing code processing the transaction...
1088 */
1089 write_lock(&journal->j_state_lock);
1090 spin_lock(&journal->j_list_lock);
1091 /*
1092 * Now recheck if some buffers did not get attached to the transaction
1093 * while the lock was dropped...
1094 */
1095 if (commit_transaction->t_forget) {
1096 spin_unlock(&journal->j_list_lock);
1097 write_unlock(&journal->j_state_lock);
1098 goto restart_loop;
1099 }
1100
1101 /* Add the transaction to the checkpoint list
1102 * __journal_remove_checkpoint() can not destroy transaction
1103 * under us because it is not marked as T_FINISHED yet */
1104 if (journal->j_checkpoint_transactions == NULL) {
1105 journal->j_checkpoint_transactions = commit_transaction;
1106 commit_transaction->t_cpnext = commit_transaction;
1107 commit_transaction->t_cpprev = commit_transaction;
1108 } else {
1109 commit_transaction->t_cpnext =
1110 journal->j_checkpoint_transactions;
1111 commit_transaction->t_cpprev =
1112 commit_transaction->t_cpnext->t_cpprev;
1113 commit_transaction->t_cpnext->t_cpprev =
1114 commit_transaction;
1115 commit_transaction->t_cpprev->t_cpnext =
1116 commit_transaction;
1117 }
1118 spin_unlock(&journal->j_list_lock);
1119
1120 /* Done with this transaction! */
1121
1122 jbd2_debug(3, "JBD2: commit phase 7\n");
1123
1124 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1125
1126 commit_transaction->t_start = jiffies;
1127 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1128 commit_transaction->t_start);
1129
1130 /*
1131 * File the transaction statistics
1132 */
1133 stats.ts_tid = commit_transaction->t_tid;
1134 stats.run.rs_handle_count =
1135 atomic_read(&commit_transaction->t_handle_count);
1136 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1137 commit_transaction->t_tid, &stats.run);
1138 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1139
1140 commit_transaction->t_state = T_COMMIT_CALLBACK;
1141 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1142 journal->j_commit_sequence = commit_transaction->t_tid;
1143 journal->j_committing_transaction = NULL;
1144 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1145
1146 /*
1147 * weight the commit time higher than the average time so we don't
1148 * react too strongly to vast changes in the commit time
1149 */
1150 if (likely(journal->j_average_commit_time))
1151 journal->j_average_commit_time = (commit_time +
1152 journal->j_average_commit_time*3) / 4;
1153 else
1154 journal->j_average_commit_time = commit_time;
1155
1156 write_unlock(&journal->j_state_lock);
1157
1158 if (journal->j_commit_callback)
1159 journal->j_commit_callback(journal, commit_transaction);
1160 if (journal->j_fc_cleanup_callback)
1161 journal->j_fc_cleanup_callback(journal, 1, commit_transaction->t_tid);
1162
1163 trace_jbd2_end_commit(journal, commit_transaction);
1164 jbd2_debug(1, "JBD2: commit %d complete, head %d\n",
1165 journal->j_commit_sequence, journal->j_tail_sequence);
1166
1167 write_lock(&journal->j_state_lock);
1168 journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1169 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1170 spin_lock(&journal->j_list_lock);
1171 commit_transaction->t_state = T_FINISHED;
1172 /* Check if the transaction can be dropped now that we are finished */
1173 if (commit_transaction->t_checkpoint_list == NULL &&
1174 commit_transaction->t_checkpoint_io_list == NULL) {
1175 __jbd2_journal_drop_transaction(journal, commit_transaction);
1176 jbd2_journal_free_transaction(commit_transaction);
1177 }
1178 spin_unlock(&journal->j_list_lock);
1179 write_unlock(&journal->j_state_lock);
1180 wake_up(&journal->j_wait_done_commit);
1181 wake_up(&journal->j_fc_wait);
1182
1183 /*
1184 * Calculate overall stats
1185 */
1186 spin_lock(&journal->j_history_lock);
1187 journal->j_stats.ts_tid++;
1188 journal->j_stats.ts_requested += stats.ts_requested;
1189 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1190 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1191 journal->j_stats.run.rs_running += stats.run.rs_running;
1192 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1193 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1194 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1195 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1196 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1197 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1198 spin_unlock(&journal->j_history_lock);
1199}
1/*
2 * linux/fs/jbd2/commit.c
3 *
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
5 *
6 * Copyright 1998 Red Hat corp --- All Rights Reserved
7 *
8 * This file is part of the Linux kernel and is made available under
9 * the terms of the GNU General Public License, version 2, or at your
10 * option, any later version, incorporated herein by reference.
11 *
12 * Journal commit routines for the generic filesystem journaling code;
13 * part of the ext2fs journaling system.
14 */
15
16#include <linux/time.h>
17#include <linux/fs.h>
18#include <linux/jbd2.h>
19#include <linux/errno.h>
20#include <linux/slab.h>
21#include <linux/mm.h>
22#include <linux/pagemap.h>
23#include <linux/jiffies.h>
24#include <linux/crc32.h>
25#include <linux/writeback.h>
26#include <linux/backing-dev.h>
27#include <linux/bio.h>
28#include <linux/blkdev.h>
29#include <linux/bitops.h>
30#include <trace/events/jbd2.h>
31
32/*
33 * IO end handler for temporary buffer_heads handling writes to the journal.
34 */
35static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
36{
37 struct buffer_head *orig_bh = bh->b_private;
38
39 BUFFER_TRACE(bh, "");
40 if (uptodate)
41 set_buffer_uptodate(bh);
42 else
43 clear_buffer_uptodate(bh);
44 if (orig_bh) {
45 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
46 smp_mb__after_atomic();
47 wake_up_bit(&orig_bh->b_state, BH_Shadow);
48 }
49 unlock_buffer(bh);
50}
51
52/*
53 * When an ext4 file is truncated, it is possible that some pages are not
54 * successfully freed, because they are attached to a committing transaction.
55 * After the transaction commits, these pages are left on the LRU, with no
56 * ->mapping, and with attached buffers. These pages are trivially reclaimable
57 * by the VM, but their apparent absence upsets the VM accounting, and it makes
58 * the numbers in /proc/meminfo look odd.
59 *
60 * So here, we have a buffer which has just come off the forget list. Look to
61 * see if we can strip all buffers from the backing page.
62 *
63 * Called under lock_journal(), and possibly under journal_datalist_lock. The
64 * caller provided us with a ref against the buffer, and we drop that here.
65 */
66static void release_buffer_page(struct buffer_head *bh)
67{
68 struct page *page;
69
70 if (buffer_dirty(bh))
71 goto nope;
72 if (atomic_read(&bh->b_count) != 1)
73 goto nope;
74 page = bh->b_page;
75 if (!page)
76 goto nope;
77 if (page->mapping)
78 goto nope;
79
80 /* OK, it's a truncated page */
81 if (!trylock_page(page))
82 goto nope;
83
84 get_page(page);
85 __brelse(bh);
86 try_to_free_buffers(page);
87 unlock_page(page);
88 put_page(page);
89 return;
90
91nope:
92 __brelse(bh);
93}
94
95static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
96{
97 struct commit_header *h;
98 __u32 csum;
99
100 if (!jbd2_journal_has_csum_v2or3(j))
101 return;
102
103 h = (struct commit_header *)(bh->b_data);
104 h->h_chksum_type = 0;
105 h->h_chksum_size = 0;
106 h->h_chksum[0] = 0;
107 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
108 h->h_chksum[0] = cpu_to_be32(csum);
109}
110
111/*
112 * Done it all: now submit the commit record. We should have
113 * cleaned up our previous buffers by now, so if we are in abort
114 * mode we can now just skip the rest of the journal write
115 * entirely.
116 *
117 * Returns 1 if the journal needs to be aborted or 0 on success
118 */
119static int journal_submit_commit_record(journal_t *journal,
120 transaction_t *commit_transaction,
121 struct buffer_head **cbh,
122 __u32 crc32_sum)
123{
124 struct commit_header *tmp;
125 struct buffer_head *bh;
126 int ret;
127 struct timespec64 now = current_kernel_time64();
128
129 *cbh = NULL;
130
131 if (is_journal_aborted(journal))
132 return 0;
133
134 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
135 JBD2_COMMIT_BLOCK);
136 if (!bh)
137 return 1;
138
139 tmp = (struct commit_header *)bh->b_data;
140 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
141 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
142
143 if (jbd2_has_feature_checksum(journal)) {
144 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
145 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
146 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
147 }
148 jbd2_commit_block_csum_set(journal, bh);
149
150 BUFFER_TRACE(bh, "submit commit block");
151 lock_buffer(bh);
152 clear_buffer_dirty(bh);
153 set_buffer_uptodate(bh);
154 bh->b_end_io = journal_end_buffer_io_sync;
155
156 if (journal->j_flags & JBD2_BARRIER &&
157 !jbd2_has_feature_async_commit(journal))
158 ret = submit_bh(REQ_OP_WRITE,
159 REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh);
160 else
161 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
162
163 *cbh = bh;
164 return ret;
165}
166
167/*
168 * This function along with journal_submit_commit_record
169 * allows to write the commit record asynchronously.
170 */
171static int journal_wait_on_commit_record(journal_t *journal,
172 struct buffer_head *bh)
173{
174 int ret = 0;
175
176 clear_buffer_dirty(bh);
177 wait_on_buffer(bh);
178
179 if (unlikely(!buffer_uptodate(bh)))
180 ret = -EIO;
181 put_bh(bh); /* One for getblk() */
182
183 return ret;
184}
185
186/*
187 * write the filemap data using writepage() address_space_operations.
188 * We don't do block allocation here even for delalloc. We don't
189 * use writepages() because with dealyed allocation we may be doing
190 * block allocation in writepages().
191 */
192static int journal_submit_inode_data_buffers(struct address_space *mapping)
193{
194 int ret;
195 struct writeback_control wbc = {
196 .sync_mode = WB_SYNC_ALL,
197 .nr_to_write = mapping->nrpages * 2,
198 .range_start = 0,
199 .range_end = i_size_read(mapping->host),
200 };
201
202 ret = generic_writepages(mapping, &wbc);
203 return ret;
204}
205
206/*
207 * Submit all the data buffers of inode associated with the transaction to
208 * disk.
209 *
210 * We are in a committing transaction. Therefore no new inode can be added to
211 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
212 * operate on from being released while we write out pages.
213 */
214static int journal_submit_data_buffers(journal_t *journal,
215 transaction_t *commit_transaction)
216{
217 struct jbd2_inode *jinode;
218 int err, ret = 0;
219 struct address_space *mapping;
220
221 spin_lock(&journal->j_list_lock);
222 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
223 if (!(jinode->i_flags & JI_WRITE_DATA))
224 continue;
225 mapping = jinode->i_vfs_inode->i_mapping;
226 jinode->i_flags |= JI_COMMIT_RUNNING;
227 spin_unlock(&journal->j_list_lock);
228 /*
229 * submit the inode data buffers. We use writepage
230 * instead of writepages. Because writepages can do
231 * block allocation with delalloc. We need to write
232 * only allocated blocks here.
233 */
234 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
235 err = journal_submit_inode_data_buffers(mapping);
236 if (!ret)
237 ret = err;
238 spin_lock(&journal->j_list_lock);
239 J_ASSERT(jinode->i_transaction == commit_transaction);
240 jinode->i_flags &= ~JI_COMMIT_RUNNING;
241 smp_mb();
242 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
243 }
244 spin_unlock(&journal->j_list_lock);
245 return ret;
246}
247
248/*
249 * Wait for data submitted for writeout, refile inodes to proper
250 * transaction if needed.
251 *
252 */
253static int journal_finish_inode_data_buffers(journal_t *journal,
254 transaction_t *commit_transaction)
255{
256 struct jbd2_inode *jinode, *next_i;
257 int err, ret = 0;
258
259 /* For locking, see the comment in journal_submit_data_buffers() */
260 spin_lock(&journal->j_list_lock);
261 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
262 if (!(jinode->i_flags & JI_WAIT_DATA))
263 continue;
264 jinode->i_flags |= JI_COMMIT_RUNNING;
265 spin_unlock(&journal->j_list_lock);
266 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
267 if (err) {
268 /*
269 * Because AS_EIO is cleared by
270 * filemap_fdatawait_range(), set it again so
271 * that user process can get -EIO from fsync().
272 */
273 mapping_set_error(jinode->i_vfs_inode->i_mapping, -EIO);
274
275 if (!ret)
276 ret = err;
277 }
278 spin_lock(&journal->j_list_lock);
279 jinode->i_flags &= ~JI_COMMIT_RUNNING;
280 smp_mb();
281 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
282 }
283
284 /* Now refile inode to proper lists */
285 list_for_each_entry_safe(jinode, next_i,
286 &commit_transaction->t_inode_list, i_list) {
287 list_del(&jinode->i_list);
288 if (jinode->i_next_transaction) {
289 jinode->i_transaction = jinode->i_next_transaction;
290 jinode->i_next_transaction = NULL;
291 list_add(&jinode->i_list,
292 &jinode->i_transaction->t_inode_list);
293 } else {
294 jinode->i_transaction = NULL;
295 }
296 }
297 spin_unlock(&journal->j_list_lock);
298
299 return ret;
300}
301
302static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
303{
304 struct page *page = bh->b_page;
305 char *addr;
306 __u32 checksum;
307
308 addr = kmap_atomic(page);
309 checksum = crc32_be(crc32_sum,
310 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
311 kunmap_atomic(addr);
312
313 return checksum;
314}
315
316static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
317 unsigned long long block)
318{
319 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
320 if (jbd2_has_feature_64bit(j))
321 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
322}
323
324static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
325 struct buffer_head *bh, __u32 sequence)
326{
327 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
328 struct page *page = bh->b_page;
329 __u8 *addr;
330 __u32 csum32;
331 __be32 seq;
332
333 if (!jbd2_journal_has_csum_v2or3(j))
334 return;
335
336 seq = cpu_to_be32(sequence);
337 addr = kmap_atomic(page);
338 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
339 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
340 bh->b_size);
341 kunmap_atomic(addr);
342
343 if (jbd2_has_feature_csum3(j))
344 tag3->t_checksum = cpu_to_be32(csum32);
345 else
346 tag->t_checksum = cpu_to_be16(csum32);
347}
348/*
349 * jbd2_journal_commit_transaction
350 *
351 * The primary function for committing a transaction to the log. This
352 * function is called by the journal thread to begin a complete commit.
353 */
354void jbd2_journal_commit_transaction(journal_t *journal)
355{
356 struct transaction_stats_s stats;
357 transaction_t *commit_transaction;
358 struct journal_head *jh;
359 struct buffer_head *descriptor;
360 struct buffer_head **wbuf = journal->j_wbuf;
361 int bufs;
362 int flags;
363 int err;
364 unsigned long long blocknr;
365 ktime_t start_time;
366 u64 commit_time;
367 char *tagp = NULL;
368 journal_block_tag_t *tag = NULL;
369 int space_left = 0;
370 int first_tag = 0;
371 int tag_flag;
372 int i;
373 int tag_bytes = journal_tag_bytes(journal);
374 struct buffer_head *cbh = NULL; /* For transactional checksums */
375 __u32 crc32_sum = ~0;
376 struct blk_plug plug;
377 /* Tail of the journal */
378 unsigned long first_block;
379 tid_t first_tid;
380 int update_tail;
381 int csum_size = 0;
382 LIST_HEAD(io_bufs);
383 LIST_HEAD(log_bufs);
384
385 if (jbd2_journal_has_csum_v2or3(journal))
386 csum_size = sizeof(struct jbd2_journal_block_tail);
387
388 /*
389 * First job: lock down the current transaction and wait for
390 * all outstanding updates to complete.
391 */
392
393 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
394 if (journal->j_flags & JBD2_FLUSHED) {
395 jbd_debug(3, "super block updated\n");
396 mutex_lock(&journal->j_checkpoint_mutex);
397 /*
398 * We hold j_checkpoint_mutex so tail cannot change under us.
399 * We don't need any special data guarantees for writing sb
400 * since journal is empty and it is ok for write to be
401 * flushed only with transaction commit.
402 */
403 jbd2_journal_update_sb_log_tail(journal,
404 journal->j_tail_sequence,
405 journal->j_tail,
406 REQ_SYNC);
407 mutex_unlock(&journal->j_checkpoint_mutex);
408 } else {
409 jbd_debug(3, "superblock not updated\n");
410 }
411
412 J_ASSERT(journal->j_running_transaction != NULL);
413 J_ASSERT(journal->j_committing_transaction == NULL);
414
415 commit_transaction = journal->j_running_transaction;
416
417 trace_jbd2_start_commit(journal, commit_transaction);
418 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
419 commit_transaction->t_tid);
420
421 write_lock(&journal->j_state_lock);
422 J_ASSERT(commit_transaction->t_state == T_RUNNING);
423 commit_transaction->t_state = T_LOCKED;
424
425 trace_jbd2_commit_locking(journal, commit_transaction);
426 stats.run.rs_wait = commit_transaction->t_max_wait;
427 stats.run.rs_request_delay = 0;
428 stats.run.rs_locked = jiffies;
429 if (commit_transaction->t_requested)
430 stats.run.rs_request_delay =
431 jbd2_time_diff(commit_transaction->t_requested,
432 stats.run.rs_locked);
433 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
434 stats.run.rs_locked);
435
436 spin_lock(&commit_transaction->t_handle_lock);
437 while (atomic_read(&commit_transaction->t_updates)) {
438 DEFINE_WAIT(wait);
439
440 prepare_to_wait(&journal->j_wait_updates, &wait,
441 TASK_UNINTERRUPTIBLE);
442 if (atomic_read(&commit_transaction->t_updates)) {
443 spin_unlock(&commit_transaction->t_handle_lock);
444 write_unlock(&journal->j_state_lock);
445 schedule();
446 write_lock(&journal->j_state_lock);
447 spin_lock(&commit_transaction->t_handle_lock);
448 }
449 finish_wait(&journal->j_wait_updates, &wait);
450 }
451 spin_unlock(&commit_transaction->t_handle_lock);
452
453 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
454 journal->j_max_transaction_buffers);
455
456 /*
457 * First thing we are allowed to do is to discard any remaining
458 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
459 * that there are no such buffers: if a large filesystem
460 * operation like a truncate needs to split itself over multiple
461 * transactions, then it may try to do a jbd2_journal_restart() while
462 * there are still BJ_Reserved buffers outstanding. These must
463 * be released cleanly from the current transaction.
464 *
465 * In this case, the filesystem must still reserve write access
466 * again before modifying the buffer in the new transaction, but
467 * we do not require it to remember exactly which old buffers it
468 * has reserved. This is consistent with the existing behaviour
469 * that multiple jbd2_journal_get_write_access() calls to the same
470 * buffer are perfectly permissible.
471 */
472 while (commit_transaction->t_reserved_list) {
473 jh = commit_transaction->t_reserved_list;
474 JBUFFER_TRACE(jh, "reserved, unused: refile");
475 /*
476 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
477 * leave undo-committed data.
478 */
479 if (jh->b_committed_data) {
480 struct buffer_head *bh = jh2bh(jh);
481
482 jbd_lock_bh_state(bh);
483 jbd2_free(jh->b_committed_data, bh->b_size);
484 jh->b_committed_data = NULL;
485 jbd_unlock_bh_state(bh);
486 }
487 jbd2_journal_refile_buffer(journal, jh);
488 }
489
490 /*
491 * Now try to drop any written-back buffers from the journal's
492 * checkpoint lists. We do this *before* commit because it potentially
493 * frees some memory
494 */
495 spin_lock(&journal->j_list_lock);
496 __jbd2_journal_clean_checkpoint_list(journal, false);
497 spin_unlock(&journal->j_list_lock);
498
499 jbd_debug(3, "JBD2: commit phase 1\n");
500
501 /*
502 * Clear revoked flag to reflect there is no revoked buffers
503 * in the next transaction which is going to be started.
504 */
505 jbd2_clear_buffer_revoked_flags(journal);
506
507 /*
508 * Switch to a new revoke table.
509 */
510 jbd2_journal_switch_revoke_table(journal);
511
512 /*
513 * Reserved credits cannot be claimed anymore, free them
514 */
515 atomic_sub(atomic_read(&journal->j_reserved_credits),
516 &commit_transaction->t_outstanding_credits);
517
518 trace_jbd2_commit_flushing(journal, commit_transaction);
519 stats.run.rs_flushing = jiffies;
520 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
521 stats.run.rs_flushing);
522
523 commit_transaction->t_state = T_FLUSH;
524 journal->j_committing_transaction = commit_transaction;
525 journal->j_running_transaction = NULL;
526 start_time = ktime_get();
527 commit_transaction->t_log_start = journal->j_head;
528 wake_up(&journal->j_wait_transaction_locked);
529 write_unlock(&journal->j_state_lock);
530
531 jbd_debug(3, "JBD2: commit phase 2a\n");
532
533 /*
534 * Now start flushing things to disk, in the order they appear
535 * on the transaction lists. Data blocks go first.
536 */
537 err = journal_submit_data_buffers(journal, commit_transaction);
538 if (err)
539 jbd2_journal_abort(journal, err);
540
541 blk_start_plug(&plug);
542 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
543
544 jbd_debug(3, "JBD2: commit phase 2b\n");
545
546 /*
547 * Way to go: we have now written out all of the data for a
548 * transaction! Now comes the tricky part: we need to write out
549 * metadata. Loop over the transaction's entire buffer list:
550 */
551 write_lock(&journal->j_state_lock);
552 commit_transaction->t_state = T_COMMIT;
553 write_unlock(&journal->j_state_lock);
554
555 trace_jbd2_commit_logging(journal, commit_transaction);
556 stats.run.rs_logging = jiffies;
557 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
558 stats.run.rs_logging);
559 stats.run.rs_blocks =
560 atomic_read(&commit_transaction->t_outstanding_credits);
561 stats.run.rs_blocks_logged = 0;
562
563 J_ASSERT(commit_transaction->t_nr_buffers <=
564 atomic_read(&commit_transaction->t_outstanding_credits));
565
566 err = 0;
567 bufs = 0;
568 descriptor = NULL;
569 while (commit_transaction->t_buffers) {
570
571 /* Find the next buffer to be journaled... */
572
573 jh = commit_transaction->t_buffers;
574
575 /* If we're in abort mode, we just un-journal the buffer and
576 release it. */
577
578 if (is_journal_aborted(journal)) {
579 clear_buffer_jbddirty(jh2bh(jh));
580 JBUFFER_TRACE(jh, "journal is aborting: refile");
581 jbd2_buffer_abort_trigger(jh,
582 jh->b_frozen_data ?
583 jh->b_frozen_triggers :
584 jh->b_triggers);
585 jbd2_journal_refile_buffer(journal, jh);
586 /* If that was the last one, we need to clean up
587 * any descriptor buffers which may have been
588 * already allocated, even if we are now
589 * aborting. */
590 if (!commit_transaction->t_buffers)
591 goto start_journal_io;
592 continue;
593 }
594
595 /* Make sure we have a descriptor block in which to
596 record the metadata buffer. */
597
598 if (!descriptor) {
599 J_ASSERT (bufs == 0);
600
601 jbd_debug(4, "JBD2: get descriptor\n");
602
603 descriptor = jbd2_journal_get_descriptor_buffer(
604 commit_transaction,
605 JBD2_DESCRIPTOR_BLOCK);
606 if (!descriptor) {
607 jbd2_journal_abort(journal, -EIO);
608 continue;
609 }
610
611 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
612 (unsigned long long)descriptor->b_blocknr,
613 descriptor->b_data);
614 tagp = &descriptor->b_data[sizeof(journal_header_t)];
615 space_left = descriptor->b_size -
616 sizeof(journal_header_t);
617 first_tag = 1;
618 set_buffer_jwrite(descriptor);
619 set_buffer_dirty(descriptor);
620 wbuf[bufs++] = descriptor;
621
622 /* Record it so that we can wait for IO
623 completion later */
624 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
625 jbd2_file_log_bh(&log_bufs, descriptor);
626 }
627
628 /* Where is the buffer to be written? */
629
630 err = jbd2_journal_next_log_block(journal, &blocknr);
631 /* If the block mapping failed, just abandon the buffer
632 and repeat this loop: we'll fall into the
633 refile-on-abort condition above. */
634 if (err) {
635 jbd2_journal_abort(journal, err);
636 continue;
637 }
638
639 /*
640 * start_this_handle() uses t_outstanding_credits to determine
641 * the free space in the log, but this counter is changed
642 * by jbd2_journal_next_log_block() also.
643 */
644 atomic_dec(&commit_transaction->t_outstanding_credits);
645
646 /* Bump b_count to prevent truncate from stumbling over
647 the shadowed buffer! @@@ This can go if we ever get
648 rid of the shadow pairing of buffers. */
649 atomic_inc(&jh2bh(jh)->b_count);
650
651 /*
652 * Make a temporary IO buffer with which to write it out
653 * (this will requeue the metadata buffer to BJ_Shadow).
654 */
655 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
656 JBUFFER_TRACE(jh, "ph3: write metadata");
657 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
658 jh, &wbuf[bufs], blocknr);
659 if (flags < 0) {
660 jbd2_journal_abort(journal, flags);
661 continue;
662 }
663 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
664
665 /* Record the new block's tag in the current descriptor
666 buffer */
667
668 tag_flag = 0;
669 if (flags & 1)
670 tag_flag |= JBD2_FLAG_ESCAPE;
671 if (!first_tag)
672 tag_flag |= JBD2_FLAG_SAME_UUID;
673
674 tag = (journal_block_tag_t *) tagp;
675 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
676 tag->t_flags = cpu_to_be16(tag_flag);
677 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
678 commit_transaction->t_tid);
679 tagp += tag_bytes;
680 space_left -= tag_bytes;
681 bufs++;
682
683 if (first_tag) {
684 memcpy (tagp, journal->j_uuid, 16);
685 tagp += 16;
686 space_left -= 16;
687 first_tag = 0;
688 }
689
690 /* If there's no more to do, or if the descriptor is full,
691 let the IO rip! */
692
693 if (bufs == journal->j_wbufsize ||
694 commit_transaction->t_buffers == NULL ||
695 space_left < tag_bytes + 16 + csum_size) {
696
697 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
698
699 /* Write an end-of-descriptor marker before
700 submitting the IOs. "tag" still points to
701 the last tag we set up. */
702
703 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
704
705 jbd2_descriptor_block_csum_set(journal, descriptor);
706start_journal_io:
707 for (i = 0; i < bufs; i++) {
708 struct buffer_head *bh = wbuf[i];
709 /*
710 * Compute checksum.
711 */
712 if (jbd2_has_feature_checksum(journal)) {
713 crc32_sum =
714 jbd2_checksum_data(crc32_sum, bh);
715 }
716
717 lock_buffer(bh);
718 clear_buffer_dirty(bh);
719 set_buffer_uptodate(bh);
720 bh->b_end_io = journal_end_buffer_io_sync;
721 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
722 }
723 cond_resched();
724 stats.run.rs_blocks_logged += bufs;
725
726 /* Force a new descriptor to be generated next
727 time round the loop. */
728 descriptor = NULL;
729 bufs = 0;
730 }
731 }
732
733 err = journal_finish_inode_data_buffers(journal, commit_transaction);
734 if (err) {
735 printk(KERN_WARNING
736 "JBD2: Detected IO errors while flushing file data "
737 "on %s\n", journal->j_devname);
738 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
739 jbd2_journal_abort(journal, err);
740 err = 0;
741 }
742
743 /*
744 * Get current oldest transaction in the log before we issue flush
745 * to the filesystem device. After the flush we can be sure that
746 * blocks of all older transactions are checkpointed to persistent
747 * storage and we will be safe to update journal start in the
748 * superblock with the numbers we get here.
749 */
750 update_tail =
751 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
752
753 write_lock(&journal->j_state_lock);
754 if (update_tail) {
755 long freed = first_block - journal->j_tail;
756
757 if (first_block < journal->j_tail)
758 freed += journal->j_last - journal->j_first;
759 /* Update tail only if we free significant amount of space */
760 if (freed < journal->j_maxlen / 4)
761 update_tail = 0;
762 }
763 J_ASSERT(commit_transaction->t_state == T_COMMIT);
764 commit_transaction->t_state = T_COMMIT_DFLUSH;
765 write_unlock(&journal->j_state_lock);
766
767 /*
768 * If the journal is not located on the file system device,
769 * then we must flush the file system device before we issue
770 * the commit record
771 */
772 if (commit_transaction->t_need_data_flush &&
773 (journal->j_fs_dev != journal->j_dev) &&
774 (journal->j_flags & JBD2_BARRIER))
775 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
776
777 /* Done it all: now write the commit record asynchronously. */
778 if (jbd2_has_feature_async_commit(journal)) {
779 err = journal_submit_commit_record(journal, commit_transaction,
780 &cbh, crc32_sum);
781 if (err)
782 __jbd2_journal_abort_hard(journal);
783 }
784
785 blk_finish_plug(&plug);
786
787 /* Lo and behold: we have just managed to send a transaction to
788 the log. Before we can commit it, wait for the IO so far to
789 complete. Control buffers being written are on the
790 transaction's t_log_list queue, and metadata buffers are on
791 the io_bufs list.
792
793 Wait for the buffers in reverse order. That way we are
794 less likely to be woken up until all IOs have completed, and
795 so we incur less scheduling load.
796 */
797
798 jbd_debug(3, "JBD2: commit phase 3\n");
799
800 while (!list_empty(&io_bufs)) {
801 struct buffer_head *bh = list_entry(io_bufs.prev,
802 struct buffer_head,
803 b_assoc_buffers);
804
805 wait_on_buffer(bh);
806 cond_resched();
807
808 if (unlikely(!buffer_uptodate(bh)))
809 err = -EIO;
810 jbd2_unfile_log_bh(bh);
811
812 /*
813 * The list contains temporary buffer heads created by
814 * jbd2_journal_write_metadata_buffer().
815 */
816 BUFFER_TRACE(bh, "dumping temporary bh");
817 __brelse(bh);
818 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
819 free_buffer_head(bh);
820
821 /* We also have to refile the corresponding shadowed buffer */
822 jh = commit_transaction->t_shadow_list->b_tprev;
823 bh = jh2bh(jh);
824 clear_buffer_jwrite(bh);
825 J_ASSERT_BH(bh, buffer_jbddirty(bh));
826 J_ASSERT_BH(bh, !buffer_shadow(bh));
827
828 /* The metadata is now released for reuse, but we need
829 to remember it against this transaction so that when
830 we finally commit, we can do any checkpointing
831 required. */
832 JBUFFER_TRACE(jh, "file as BJ_Forget");
833 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
834 JBUFFER_TRACE(jh, "brelse shadowed buffer");
835 __brelse(bh);
836 }
837
838 J_ASSERT (commit_transaction->t_shadow_list == NULL);
839
840 jbd_debug(3, "JBD2: commit phase 4\n");
841
842 /* Here we wait for the revoke record and descriptor record buffers */
843 while (!list_empty(&log_bufs)) {
844 struct buffer_head *bh;
845
846 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
847 wait_on_buffer(bh);
848 cond_resched();
849
850 if (unlikely(!buffer_uptodate(bh)))
851 err = -EIO;
852
853 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
854 clear_buffer_jwrite(bh);
855 jbd2_unfile_log_bh(bh);
856 __brelse(bh); /* One for getblk */
857 /* AKPM: bforget here */
858 }
859
860 if (err)
861 jbd2_journal_abort(journal, err);
862
863 jbd_debug(3, "JBD2: commit phase 5\n");
864 write_lock(&journal->j_state_lock);
865 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
866 commit_transaction->t_state = T_COMMIT_JFLUSH;
867 write_unlock(&journal->j_state_lock);
868
869 if (!jbd2_has_feature_async_commit(journal)) {
870 err = journal_submit_commit_record(journal, commit_transaction,
871 &cbh, crc32_sum);
872 if (err)
873 __jbd2_journal_abort_hard(journal);
874 }
875 if (cbh)
876 err = journal_wait_on_commit_record(journal, cbh);
877 if (jbd2_has_feature_async_commit(journal) &&
878 journal->j_flags & JBD2_BARRIER) {
879 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
880 }
881
882 if (err)
883 jbd2_journal_abort(journal, err);
884
885 /*
886 * Now disk caches for filesystem device are flushed so we are safe to
887 * erase checkpointed transactions from the log by updating journal
888 * superblock.
889 */
890 if (update_tail)
891 jbd2_update_log_tail(journal, first_tid, first_block);
892
893 /* End of a transaction! Finally, we can do checkpoint
894 processing: any buffers committed as a result of this
895 transaction can be removed from any checkpoint list it was on
896 before. */
897
898 jbd_debug(3, "JBD2: commit phase 6\n");
899
900 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
901 J_ASSERT(commit_transaction->t_buffers == NULL);
902 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
903 J_ASSERT(commit_transaction->t_shadow_list == NULL);
904
905restart_loop:
906 /*
907 * As there are other places (journal_unmap_buffer()) adding buffers
908 * to this list we have to be careful and hold the j_list_lock.
909 */
910 spin_lock(&journal->j_list_lock);
911 while (commit_transaction->t_forget) {
912 transaction_t *cp_transaction;
913 struct buffer_head *bh;
914 int try_to_free = 0;
915
916 jh = commit_transaction->t_forget;
917 spin_unlock(&journal->j_list_lock);
918 bh = jh2bh(jh);
919 /*
920 * Get a reference so that bh cannot be freed before we are
921 * done with it.
922 */
923 get_bh(bh);
924 jbd_lock_bh_state(bh);
925 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
926
927 /*
928 * If there is undo-protected committed data against
929 * this buffer, then we can remove it now. If it is a
930 * buffer needing such protection, the old frozen_data
931 * field now points to a committed version of the
932 * buffer, so rotate that field to the new committed
933 * data.
934 *
935 * Otherwise, we can just throw away the frozen data now.
936 *
937 * We also know that the frozen data has already fired
938 * its triggers if they exist, so we can clear that too.
939 */
940 if (jh->b_committed_data) {
941 jbd2_free(jh->b_committed_data, bh->b_size);
942 jh->b_committed_data = NULL;
943 if (jh->b_frozen_data) {
944 jh->b_committed_data = jh->b_frozen_data;
945 jh->b_frozen_data = NULL;
946 jh->b_frozen_triggers = NULL;
947 }
948 } else if (jh->b_frozen_data) {
949 jbd2_free(jh->b_frozen_data, bh->b_size);
950 jh->b_frozen_data = NULL;
951 jh->b_frozen_triggers = NULL;
952 }
953
954 spin_lock(&journal->j_list_lock);
955 cp_transaction = jh->b_cp_transaction;
956 if (cp_transaction) {
957 JBUFFER_TRACE(jh, "remove from old cp transaction");
958 cp_transaction->t_chp_stats.cs_dropped++;
959 __jbd2_journal_remove_checkpoint(jh);
960 }
961
962 /* Only re-checkpoint the buffer_head if it is marked
963 * dirty. If the buffer was added to the BJ_Forget list
964 * by jbd2_journal_forget, it may no longer be dirty and
965 * there's no point in keeping a checkpoint record for
966 * it. */
967
968 /*
969 * A buffer which has been freed while still being journaled by
970 * a previous transaction.
971 */
972 if (buffer_freed(bh)) {
973 /*
974 * If the running transaction is the one containing
975 * "add to orphan" operation (b_next_transaction !=
976 * NULL), we have to wait for that transaction to
977 * commit before we can really get rid of the buffer.
978 * So just clear b_modified to not confuse transaction
979 * credit accounting and refile the buffer to
980 * BJ_Forget of the running transaction. If the just
981 * committed transaction contains "add to orphan"
982 * operation, we can completely invalidate the buffer
983 * now. We are rather through in that since the
984 * buffer may be still accessible when blocksize <
985 * pagesize and it is attached to the last partial
986 * page.
987 */
988 jh->b_modified = 0;
989 if (!jh->b_next_transaction) {
990 clear_buffer_freed(bh);
991 clear_buffer_jbddirty(bh);
992 clear_buffer_mapped(bh);
993 clear_buffer_new(bh);
994 clear_buffer_req(bh);
995 bh->b_bdev = NULL;
996 }
997 }
998
999 if (buffer_jbddirty(bh)) {
1000 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1001 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1002 if (is_journal_aborted(journal))
1003 clear_buffer_jbddirty(bh);
1004 } else {
1005 J_ASSERT_BH(bh, !buffer_dirty(bh));
1006 /*
1007 * The buffer on BJ_Forget list and not jbddirty means
1008 * it has been freed by this transaction and hence it
1009 * could not have been reallocated until this
1010 * transaction has committed. *BUT* it could be
1011 * reallocated once we have written all the data to
1012 * disk and before we process the buffer on BJ_Forget
1013 * list.
1014 */
1015 if (!jh->b_next_transaction)
1016 try_to_free = 1;
1017 }
1018 JBUFFER_TRACE(jh, "refile or unfile buffer");
1019 __jbd2_journal_refile_buffer(jh);
1020 jbd_unlock_bh_state(bh);
1021 if (try_to_free)
1022 release_buffer_page(bh); /* Drops bh reference */
1023 else
1024 __brelse(bh);
1025 cond_resched_lock(&journal->j_list_lock);
1026 }
1027 spin_unlock(&journal->j_list_lock);
1028 /*
1029 * This is a bit sleazy. We use j_list_lock to protect transition
1030 * of a transaction into T_FINISHED state and calling
1031 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1032 * other checkpointing code processing the transaction...
1033 */
1034 write_lock(&journal->j_state_lock);
1035 spin_lock(&journal->j_list_lock);
1036 /*
1037 * Now recheck if some buffers did not get attached to the transaction
1038 * while the lock was dropped...
1039 */
1040 if (commit_transaction->t_forget) {
1041 spin_unlock(&journal->j_list_lock);
1042 write_unlock(&journal->j_state_lock);
1043 goto restart_loop;
1044 }
1045
1046 /* Add the transaction to the checkpoint list
1047 * __journal_remove_checkpoint() can not destroy transaction
1048 * under us because it is not marked as T_FINISHED yet */
1049 if (journal->j_checkpoint_transactions == NULL) {
1050 journal->j_checkpoint_transactions = commit_transaction;
1051 commit_transaction->t_cpnext = commit_transaction;
1052 commit_transaction->t_cpprev = commit_transaction;
1053 } else {
1054 commit_transaction->t_cpnext =
1055 journal->j_checkpoint_transactions;
1056 commit_transaction->t_cpprev =
1057 commit_transaction->t_cpnext->t_cpprev;
1058 commit_transaction->t_cpnext->t_cpprev =
1059 commit_transaction;
1060 commit_transaction->t_cpprev->t_cpnext =
1061 commit_transaction;
1062 }
1063 spin_unlock(&journal->j_list_lock);
1064
1065 /* Done with this transaction! */
1066
1067 jbd_debug(3, "JBD2: commit phase 7\n");
1068
1069 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1070
1071 commit_transaction->t_start = jiffies;
1072 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1073 commit_transaction->t_start);
1074
1075 /*
1076 * File the transaction statistics
1077 */
1078 stats.ts_tid = commit_transaction->t_tid;
1079 stats.run.rs_handle_count =
1080 atomic_read(&commit_transaction->t_handle_count);
1081 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1082 commit_transaction->t_tid, &stats.run);
1083 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1084
1085 commit_transaction->t_state = T_COMMIT_CALLBACK;
1086 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1087 journal->j_commit_sequence = commit_transaction->t_tid;
1088 journal->j_committing_transaction = NULL;
1089 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1090
1091 /*
1092 * weight the commit time higher than the average time so we don't
1093 * react too strongly to vast changes in the commit time
1094 */
1095 if (likely(journal->j_average_commit_time))
1096 journal->j_average_commit_time = (commit_time +
1097 journal->j_average_commit_time*3) / 4;
1098 else
1099 journal->j_average_commit_time = commit_time;
1100
1101 write_unlock(&journal->j_state_lock);
1102
1103 if (journal->j_commit_callback)
1104 journal->j_commit_callback(journal, commit_transaction);
1105
1106 trace_jbd2_end_commit(journal, commit_transaction);
1107 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1108 journal->j_commit_sequence, journal->j_tail_sequence);
1109
1110 write_lock(&journal->j_state_lock);
1111 spin_lock(&journal->j_list_lock);
1112 commit_transaction->t_state = T_FINISHED;
1113 /* Check if the transaction can be dropped now that we are finished */
1114 if (commit_transaction->t_checkpoint_list == NULL &&
1115 commit_transaction->t_checkpoint_io_list == NULL) {
1116 __jbd2_journal_drop_transaction(journal, commit_transaction);
1117 jbd2_journal_free_transaction(commit_transaction);
1118 }
1119 spin_unlock(&journal->j_list_lock);
1120 write_unlock(&journal->j_state_lock);
1121 wake_up(&journal->j_wait_done_commit);
1122
1123 /*
1124 * Calculate overall stats
1125 */
1126 spin_lock(&journal->j_history_lock);
1127 journal->j_stats.ts_tid++;
1128 journal->j_stats.ts_requested += stats.ts_requested;
1129 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1130 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1131 journal->j_stats.run.rs_running += stats.run.rs_running;
1132 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1133 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1134 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1135 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1136 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1137 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1138 spin_unlock(&journal->j_history_lock);
1139}