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