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1/*
2 * linux/fs/jbd2/commit.c
3 *
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
5 *
6 * Copyright 1998 Red Hat corp --- All Rights Reserved
7 *
8 * This file is part of the Linux kernel and is made available under
9 * the terms of the GNU General Public License, version 2, or at your
10 * option, any later version, incorporated herein by reference.
11 *
12 * Journal commit routines for the generic filesystem journaling code;
13 * part of the ext2fs journaling system.
14 */
15
16#include <linux/time.h>
17#include <linux/fs.h>
18#include <linux/jbd2.h>
19#include <linux/errno.h>
20#include <linux/slab.h>
21#include <linux/mm.h>
22#include <linux/pagemap.h>
23#include <linux/jiffies.h>
24#include <linux/crc32.h>
25#include <linux/writeback.h>
26#include <linux/backing-dev.h>
27#include <linux/bio.h>
28#include <linux/blkdev.h>
29#include <linux/bitops.h>
30#include <trace/events/jbd2.h>
31
32/*
33 * IO end handler for temporary buffer_heads handling writes to the journal.
34 */
35static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
36{
37 struct buffer_head *orig_bh = bh->b_private;
38
39 BUFFER_TRACE(bh, "");
40 if (uptodate)
41 set_buffer_uptodate(bh);
42 else
43 clear_buffer_uptodate(bh);
44 if (orig_bh) {
45 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
46 smp_mb__after_atomic();
47 wake_up_bit(&orig_bh->b_state, BH_Shadow);
48 }
49 unlock_buffer(bh);
50}
51
52/*
53 * When an ext4 file is truncated, it is possible that some pages are not
54 * successfully freed, because they are attached to a committing transaction.
55 * After the transaction commits, these pages are left on the LRU, with no
56 * ->mapping, and with attached buffers. These pages are trivially reclaimable
57 * by the VM, but their apparent absence upsets the VM accounting, and it makes
58 * the numbers in /proc/meminfo look odd.
59 *
60 * So here, we have a buffer which has just come off the forget list. Look to
61 * see if we can strip all buffers from the backing page.
62 *
63 * Called under lock_journal(), and possibly under journal_datalist_lock. The
64 * caller provided us with a ref against the buffer, and we drop that here.
65 */
66static void release_buffer_page(struct buffer_head *bh)
67{
68 struct page *page;
69
70 if (buffer_dirty(bh))
71 goto nope;
72 if (atomic_read(&bh->b_count) != 1)
73 goto nope;
74 page = bh->b_page;
75 if (!page)
76 goto nope;
77 if (page->mapping)
78 goto nope;
79
80 /* OK, it's a truncated page */
81 if (!trylock_page(page))
82 goto nope;
83
84 get_page(page);
85 __brelse(bh);
86 try_to_free_buffers(page);
87 unlock_page(page);
88 put_page(page);
89 return;
90
91nope:
92 __brelse(bh);
93}
94
95static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
96{
97 struct commit_header *h;
98 __u32 csum;
99
100 if (!jbd2_journal_has_csum_v2or3(j))
101 return;
102
103 h = (struct commit_header *)(bh->b_data);
104 h->h_chksum_type = 0;
105 h->h_chksum_size = 0;
106 h->h_chksum[0] = 0;
107 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
108 h->h_chksum[0] = cpu_to_be32(csum);
109}
110
111/*
112 * Done it all: now submit the commit record. We should have
113 * cleaned up our previous buffers by now, so if we are in abort
114 * mode we can now just skip the rest of the journal write
115 * entirely.
116 *
117 * Returns 1 if the journal needs to be aborted or 0 on success
118 */
119static int journal_submit_commit_record(journal_t *journal,
120 transaction_t *commit_transaction,
121 struct buffer_head **cbh,
122 __u32 crc32_sum)
123{
124 struct commit_header *tmp;
125 struct buffer_head *bh;
126 int ret;
127 struct timespec now = current_kernel_time();
128
129 *cbh = NULL;
130
131 if (is_journal_aborted(journal))
132 return 0;
133
134 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
135 JBD2_COMMIT_BLOCK);
136 if (!bh)
137 return 1;
138
139 tmp = (struct commit_header *)bh->b_data;
140 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
141 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
142
143 if (jbd2_has_feature_checksum(journal)) {
144 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
145 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
146 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
147 }
148 jbd2_commit_block_csum_set(journal, bh);
149
150 BUFFER_TRACE(bh, "submit commit block");
151 lock_buffer(bh);
152 clear_buffer_dirty(bh);
153 set_buffer_uptodate(bh);
154 bh->b_end_io = journal_end_buffer_io_sync;
155
156 if (journal->j_flags & JBD2_BARRIER &&
157 !jbd2_has_feature_async_commit(journal))
158 ret = submit_bh(WRITE_SYNC | WRITE_FLUSH_FUA, bh);
159 else
160 ret = submit_bh(WRITE_SYNC, bh);
161
162 *cbh = bh;
163 return ret;
164}
165
166/*
167 * This function along with journal_submit_commit_record
168 * allows to write the commit record asynchronously.
169 */
170static int journal_wait_on_commit_record(journal_t *journal,
171 struct buffer_head *bh)
172{
173 int ret = 0;
174
175 clear_buffer_dirty(bh);
176 wait_on_buffer(bh);
177
178 if (unlikely(!buffer_uptodate(bh)))
179 ret = -EIO;
180 put_bh(bh); /* One for getblk() */
181
182 return ret;
183}
184
185/*
186 * write the filemap data using writepage() address_space_operations.
187 * We don't do block allocation here even for delalloc. We don't
188 * use writepages() because with dealyed allocation we may be doing
189 * block allocation in writepages().
190 */
191static int journal_submit_inode_data_buffers(struct address_space *mapping)
192{
193 int ret;
194 struct writeback_control wbc = {
195 .sync_mode = WB_SYNC_ALL,
196 .nr_to_write = mapping->nrpages * 2,
197 .range_start = 0,
198 .range_end = i_size_read(mapping->host),
199 };
200
201 ret = generic_writepages(mapping, &wbc);
202 return ret;
203}
204
205/*
206 * Submit all the data buffers of inode associated with the transaction to
207 * disk.
208 *
209 * We are in a committing transaction. Therefore no new inode can be added to
210 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
211 * operate on from being released while we write out pages.
212 */
213static int journal_submit_data_buffers(journal_t *journal,
214 transaction_t *commit_transaction)
215{
216 struct jbd2_inode *jinode;
217 int err, ret = 0;
218 struct address_space *mapping;
219
220 spin_lock(&journal->j_list_lock);
221 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
222 mapping = jinode->i_vfs_inode->i_mapping;
223 jinode->i_flags |= JI_COMMIT_RUNNING;
224 spin_unlock(&journal->j_list_lock);
225 /*
226 * submit the inode data buffers. We use writepage
227 * instead of writepages. Because writepages can do
228 * block allocation with delalloc. We need to write
229 * only allocated blocks here.
230 */
231 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
232 err = journal_submit_inode_data_buffers(mapping);
233 if (!ret)
234 ret = err;
235 spin_lock(&journal->j_list_lock);
236 J_ASSERT(jinode->i_transaction == commit_transaction);
237 jinode->i_flags &= ~JI_COMMIT_RUNNING;
238 smp_mb();
239 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
240 }
241 spin_unlock(&journal->j_list_lock);
242 return ret;
243}
244
245/*
246 * Wait for data submitted for writeout, refile inodes to proper
247 * transaction if needed.
248 *
249 */
250static int journal_finish_inode_data_buffers(journal_t *journal,
251 transaction_t *commit_transaction)
252{
253 struct jbd2_inode *jinode, *next_i;
254 int err, ret = 0;
255
256 /* For locking, see the comment in journal_submit_data_buffers() */
257 spin_lock(&journal->j_list_lock);
258 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
259 jinode->i_flags |= JI_COMMIT_RUNNING;
260 spin_unlock(&journal->j_list_lock);
261 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
262 if (err) {
263 /*
264 * Because AS_EIO is cleared by
265 * filemap_fdatawait_range(), set it again so
266 * that user process can get -EIO from fsync().
267 */
268 set_bit(AS_EIO,
269 &jinode->i_vfs_inode->i_mapping->flags);
270
271 if (!ret)
272 ret = err;
273 }
274 spin_lock(&journal->j_list_lock);
275 jinode->i_flags &= ~JI_COMMIT_RUNNING;
276 smp_mb();
277 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
278 }
279
280 /* Now refile inode to proper lists */
281 list_for_each_entry_safe(jinode, next_i,
282 &commit_transaction->t_inode_list, i_list) {
283 list_del(&jinode->i_list);
284 if (jinode->i_next_transaction) {
285 jinode->i_transaction = jinode->i_next_transaction;
286 jinode->i_next_transaction = NULL;
287 list_add(&jinode->i_list,
288 &jinode->i_transaction->t_inode_list);
289 } else {
290 jinode->i_transaction = NULL;
291 }
292 }
293 spin_unlock(&journal->j_list_lock);
294
295 return ret;
296}
297
298static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
299{
300 struct page *page = bh->b_page;
301 char *addr;
302 __u32 checksum;
303
304 addr = kmap_atomic(page);
305 checksum = crc32_be(crc32_sum,
306 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
307 kunmap_atomic(addr);
308
309 return checksum;
310}
311
312static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
313 unsigned long long block)
314{
315 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
316 if (jbd2_has_feature_64bit(j))
317 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
318}
319
320static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
321 struct buffer_head *bh, __u32 sequence)
322{
323 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
324 struct page *page = bh->b_page;
325 __u8 *addr;
326 __u32 csum32;
327 __be32 seq;
328
329 if (!jbd2_journal_has_csum_v2or3(j))
330 return;
331
332 seq = cpu_to_be32(sequence);
333 addr = kmap_atomic(page);
334 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
335 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
336 bh->b_size);
337 kunmap_atomic(addr);
338
339 if (jbd2_has_feature_csum3(j))
340 tag3->t_checksum = cpu_to_be32(csum32);
341 else
342 tag->t_checksum = cpu_to_be16(csum32);
343}
344/*
345 * jbd2_journal_commit_transaction
346 *
347 * The primary function for committing a transaction to the log. This
348 * function is called by the journal thread to begin a complete commit.
349 */
350void jbd2_journal_commit_transaction(journal_t *journal)
351{
352 struct transaction_stats_s stats;
353 transaction_t *commit_transaction;
354 struct journal_head *jh;
355 struct buffer_head *descriptor;
356 struct buffer_head **wbuf = journal->j_wbuf;
357 int bufs;
358 int flags;
359 int err;
360 unsigned long long blocknr;
361 ktime_t start_time;
362 u64 commit_time;
363 char *tagp = NULL;
364 journal_block_tag_t *tag = NULL;
365 int space_left = 0;
366 int first_tag = 0;
367 int tag_flag;
368 int i;
369 int tag_bytes = journal_tag_bytes(journal);
370 struct buffer_head *cbh = NULL; /* For transactional checksums */
371 __u32 crc32_sum = ~0;
372 struct blk_plug plug;
373 /* Tail of the journal */
374 unsigned long first_block;
375 tid_t first_tid;
376 int update_tail;
377 int csum_size = 0;
378 LIST_HEAD(io_bufs);
379 LIST_HEAD(log_bufs);
380
381 if (jbd2_journal_has_csum_v2or3(journal))
382 csum_size = sizeof(struct jbd2_journal_block_tail);
383
384 /*
385 * First job: lock down the current transaction and wait for
386 * all outstanding updates to complete.
387 */
388
389 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
390 if (journal->j_flags & JBD2_FLUSHED) {
391 jbd_debug(3, "super block updated\n");
392 mutex_lock(&journal->j_checkpoint_mutex);
393 /*
394 * We hold j_checkpoint_mutex so tail cannot change under us.
395 * We don't need any special data guarantees for writing sb
396 * since journal is empty and it is ok for write to be
397 * flushed only with transaction commit.
398 */
399 jbd2_journal_update_sb_log_tail(journal,
400 journal->j_tail_sequence,
401 journal->j_tail,
402 WRITE_SYNC);
403 mutex_unlock(&journal->j_checkpoint_mutex);
404 } else {
405 jbd_debug(3, "superblock not updated\n");
406 }
407
408 J_ASSERT(journal->j_running_transaction != NULL);
409 J_ASSERT(journal->j_committing_transaction == NULL);
410
411 commit_transaction = journal->j_running_transaction;
412
413 trace_jbd2_start_commit(journal, commit_transaction);
414 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
415 commit_transaction->t_tid);
416
417 write_lock(&journal->j_state_lock);
418 J_ASSERT(commit_transaction->t_state == T_RUNNING);
419 commit_transaction->t_state = T_LOCKED;
420
421 trace_jbd2_commit_locking(journal, commit_transaction);
422 stats.run.rs_wait = commit_transaction->t_max_wait;
423 stats.run.rs_request_delay = 0;
424 stats.run.rs_locked = jiffies;
425 if (commit_transaction->t_requested)
426 stats.run.rs_request_delay =
427 jbd2_time_diff(commit_transaction->t_requested,
428 stats.run.rs_locked);
429 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
430 stats.run.rs_locked);
431
432 spin_lock(&commit_transaction->t_handle_lock);
433 while (atomic_read(&commit_transaction->t_updates)) {
434 DEFINE_WAIT(wait);
435
436 prepare_to_wait(&journal->j_wait_updates, &wait,
437 TASK_UNINTERRUPTIBLE);
438 if (atomic_read(&commit_transaction->t_updates)) {
439 spin_unlock(&commit_transaction->t_handle_lock);
440 write_unlock(&journal->j_state_lock);
441 schedule();
442 write_lock(&journal->j_state_lock);
443 spin_lock(&commit_transaction->t_handle_lock);
444 }
445 finish_wait(&journal->j_wait_updates, &wait);
446 }
447 spin_unlock(&commit_transaction->t_handle_lock);
448
449 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
450 journal->j_max_transaction_buffers);
451
452 /*
453 * First thing we are allowed to do is to discard any remaining
454 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
455 * that there are no such buffers: if a large filesystem
456 * operation like a truncate needs to split itself over multiple
457 * transactions, then it may try to do a jbd2_journal_restart() while
458 * there are still BJ_Reserved buffers outstanding. These must
459 * be released cleanly from the current transaction.
460 *
461 * In this case, the filesystem must still reserve write access
462 * again before modifying the buffer in the new transaction, but
463 * we do not require it to remember exactly which old buffers it
464 * has reserved. This is consistent with the existing behaviour
465 * that multiple jbd2_journal_get_write_access() calls to the same
466 * buffer are perfectly permissible.
467 */
468 while (commit_transaction->t_reserved_list) {
469 jh = commit_transaction->t_reserved_list;
470 JBUFFER_TRACE(jh, "reserved, unused: refile");
471 /*
472 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
473 * leave undo-committed data.
474 */
475 if (jh->b_committed_data) {
476 struct buffer_head *bh = jh2bh(jh);
477
478 jbd_lock_bh_state(bh);
479 jbd2_free(jh->b_committed_data, bh->b_size);
480 jh->b_committed_data = NULL;
481 jbd_unlock_bh_state(bh);
482 }
483 jbd2_journal_refile_buffer(journal, jh);
484 }
485
486 /*
487 * Now try to drop any written-back buffers from the journal's
488 * checkpoint lists. We do this *before* commit because it potentially
489 * frees some memory
490 */
491 spin_lock(&journal->j_list_lock);
492 __jbd2_journal_clean_checkpoint_list(journal, false);
493 spin_unlock(&journal->j_list_lock);
494
495 jbd_debug(3, "JBD2: commit phase 1\n");
496
497 /*
498 * Clear revoked flag to reflect there is no revoked buffers
499 * in the next transaction which is going to be started.
500 */
501 jbd2_clear_buffer_revoked_flags(journal);
502
503 /*
504 * Switch to a new revoke table.
505 */
506 jbd2_journal_switch_revoke_table(journal);
507
508 /*
509 * Reserved credits cannot be claimed anymore, free them
510 */
511 atomic_sub(atomic_read(&journal->j_reserved_credits),
512 &commit_transaction->t_outstanding_credits);
513
514 trace_jbd2_commit_flushing(journal, commit_transaction);
515 stats.run.rs_flushing = jiffies;
516 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
517 stats.run.rs_flushing);
518
519 commit_transaction->t_state = T_FLUSH;
520 journal->j_committing_transaction = commit_transaction;
521 journal->j_running_transaction = NULL;
522 start_time = ktime_get();
523 commit_transaction->t_log_start = journal->j_head;
524 wake_up(&journal->j_wait_transaction_locked);
525 write_unlock(&journal->j_state_lock);
526
527 jbd_debug(3, "JBD2: commit phase 2a\n");
528
529 /*
530 * Now start flushing things to disk, in the order they appear
531 * on the transaction lists. Data blocks go first.
532 */
533 err = journal_submit_data_buffers(journal, commit_transaction);
534 if (err)
535 jbd2_journal_abort(journal, err);
536
537 blk_start_plug(&plug);
538 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
539
540 jbd_debug(3, "JBD2: commit phase 2b\n");
541
542 /*
543 * Way to go: we have now written out all of the data for a
544 * transaction! Now comes the tricky part: we need to write out
545 * metadata. Loop over the transaction's entire buffer list:
546 */
547 write_lock(&journal->j_state_lock);
548 commit_transaction->t_state = T_COMMIT;
549 write_unlock(&journal->j_state_lock);
550
551 trace_jbd2_commit_logging(journal, commit_transaction);
552 stats.run.rs_logging = jiffies;
553 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
554 stats.run.rs_logging);
555 stats.run.rs_blocks =
556 atomic_read(&commit_transaction->t_outstanding_credits);
557 stats.run.rs_blocks_logged = 0;
558
559 J_ASSERT(commit_transaction->t_nr_buffers <=
560 atomic_read(&commit_transaction->t_outstanding_credits));
561
562 err = 0;
563 bufs = 0;
564 descriptor = NULL;
565 while (commit_transaction->t_buffers) {
566
567 /* Find the next buffer to be journaled... */
568
569 jh = commit_transaction->t_buffers;
570
571 /* If we're in abort mode, we just un-journal the buffer and
572 release it. */
573
574 if (is_journal_aborted(journal)) {
575 clear_buffer_jbddirty(jh2bh(jh));
576 JBUFFER_TRACE(jh, "journal is aborting: refile");
577 jbd2_buffer_abort_trigger(jh,
578 jh->b_frozen_data ?
579 jh->b_frozen_triggers :
580 jh->b_triggers);
581 jbd2_journal_refile_buffer(journal, jh);
582 /* If that was the last one, we need to clean up
583 * any descriptor buffers which may have been
584 * already allocated, even if we are now
585 * aborting. */
586 if (!commit_transaction->t_buffers)
587 goto start_journal_io;
588 continue;
589 }
590
591 /* Make sure we have a descriptor block in which to
592 record the metadata buffer. */
593
594 if (!descriptor) {
595 J_ASSERT (bufs == 0);
596
597 jbd_debug(4, "JBD2: get descriptor\n");
598
599 descriptor = jbd2_journal_get_descriptor_buffer(
600 commit_transaction,
601 JBD2_DESCRIPTOR_BLOCK);
602 if (!descriptor) {
603 jbd2_journal_abort(journal, -EIO);
604 continue;
605 }
606
607 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
608 (unsigned long long)descriptor->b_blocknr,
609 descriptor->b_data);
610 tagp = &descriptor->b_data[sizeof(journal_header_t)];
611 space_left = descriptor->b_size -
612 sizeof(journal_header_t);
613 first_tag = 1;
614 set_buffer_jwrite(descriptor);
615 set_buffer_dirty(descriptor);
616 wbuf[bufs++] = descriptor;
617
618 /* Record it so that we can wait for IO
619 completion later */
620 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
621 jbd2_file_log_bh(&log_bufs, descriptor);
622 }
623
624 /* Where is the buffer to be written? */
625
626 err = jbd2_journal_next_log_block(journal, &blocknr);
627 /* If the block mapping failed, just abandon the buffer
628 and repeat this loop: we'll fall into the
629 refile-on-abort condition above. */
630 if (err) {
631 jbd2_journal_abort(journal, err);
632 continue;
633 }
634
635 /*
636 * start_this_handle() uses t_outstanding_credits to determine
637 * the free space in the log, but this counter is changed
638 * by jbd2_journal_next_log_block() also.
639 */
640 atomic_dec(&commit_transaction->t_outstanding_credits);
641
642 /* Bump b_count to prevent truncate from stumbling over
643 the shadowed buffer! @@@ This can go if we ever get
644 rid of the shadow pairing of buffers. */
645 atomic_inc(&jh2bh(jh)->b_count);
646
647 /*
648 * Make a temporary IO buffer with which to write it out
649 * (this will requeue the metadata buffer to BJ_Shadow).
650 */
651 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
652 JBUFFER_TRACE(jh, "ph3: write metadata");
653 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
654 jh, &wbuf[bufs], blocknr);
655 if (flags < 0) {
656 jbd2_journal_abort(journal, flags);
657 continue;
658 }
659 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
660
661 /* Record the new block's tag in the current descriptor
662 buffer */
663
664 tag_flag = 0;
665 if (flags & 1)
666 tag_flag |= JBD2_FLAG_ESCAPE;
667 if (!first_tag)
668 tag_flag |= JBD2_FLAG_SAME_UUID;
669
670 tag = (journal_block_tag_t *) tagp;
671 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
672 tag->t_flags = cpu_to_be16(tag_flag);
673 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
674 commit_transaction->t_tid);
675 tagp += tag_bytes;
676 space_left -= tag_bytes;
677 bufs++;
678
679 if (first_tag) {
680 memcpy (tagp, journal->j_uuid, 16);
681 tagp += 16;
682 space_left -= 16;
683 first_tag = 0;
684 }
685
686 /* If there's no more to do, or if the descriptor is full,
687 let the IO rip! */
688
689 if (bufs == journal->j_wbufsize ||
690 commit_transaction->t_buffers == NULL ||
691 space_left < tag_bytes + 16 + csum_size) {
692
693 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
694
695 /* Write an end-of-descriptor marker before
696 submitting the IOs. "tag" still points to
697 the last tag we set up. */
698
699 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
700
701 jbd2_descriptor_block_csum_set(journal, descriptor);
702start_journal_io:
703 for (i = 0; i < bufs; i++) {
704 struct buffer_head *bh = wbuf[i];
705 /*
706 * Compute checksum.
707 */
708 if (jbd2_has_feature_checksum(journal)) {
709 crc32_sum =
710 jbd2_checksum_data(crc32_sum, bh);
711 }
712
713 lock_buffer(bh);
714 clear_buffer_dirty(bh);
715 set_buffer_uptodate(bh);
716 bh->b_end_io = journal_end_buffer_io_sync;
717 submit_bh(WRITE_SYNC, bh);
718 }
719 cond_resched();
720 stats.run.rs_blocks_logged += bufs;
721
722 /* Force a new descriptor to be generated next
723 time round the loop. */
724 descriptor = NULL;
725 bufs = 0;
726 }
727 }
728
729 err = journal_finish_inode_data_buffers(journal, commit_transaction);
730 if (err) {
731 printk(KERN_WARNING
732 "JBD2: Detected IO errors while flushing file data "
733 "on %s\n", journal->j_devname);
734 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
735 jbd2_journal_abort(journal, err);
736 err = 0;
737 }
738
739 /*
740 * Get current oldest transaction in the log before we issue flush
741 * to the filesystem device. After the flush we can be sure that
742 * blocks of all older transactions are checkpointed to persistent
743 * storage and we will be safe to update journal start in the
744 * superblock with the numbers we get here.
745 */
746 update_tail =
747 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
748
749 write_lock(&journal->j_state_lock);
750 if (update_tail) {
751 long freed = first_block - journal->j_tail;
752
753 if (first_block < journal->j_tail)
754 freed += journal->j_last - journal->j_first;
755 /* Update tail only if we free significant amount of space */
756 if (freed < journal->j_maxlen / 4)
757 update_tail = 0;
758 }
759 J_ASSERT(commit_transaction->t_state == T_COMMIT);
760 commit_transaction->t_state = T_COMMIT_DFLUSH;
761 write_unlock(&journal->j_state_lock);
762
763 /*
764 * If the journal is not located on the file system device,
765 * then we must flush the file system device before we issue
766 * the commit record
767 */
768 if (commit_transaction->t_need_data_flush &&
769 (journal->j_fs_dev != journal->j_dev) &&
770 (journal->j_flags & JBD2_BARRIER))
771 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
772
773 /* Done it all: now write the commit record asynchronously. */
774 if (jbd2_has_feature_async_commit(journal)) {
775 err = journal_submit_commit_record(journal, commit_transaction,
776 &cbh, crc32_sum);
777 if (err)
778 __jbd2_journal_abort_hard(journal);
779 }
780
781 blk_finish_plug(&plug);
782
783 /* Lo and behold: we have just managed to send a transaction to
784 the log. Before we can commit it, wait for the IO so far to
785 complete. Control buffers being written are on the
786 transaction's t_log_list queue, and metadata buffers are on
787 the io_bufs list.
788
789 Wait for the buffers in reverse order. That way we are
790 less likely to be woken up until all IOs have completed, and
791 so we incur less scheduling load.
792 */
793
794 jbd_debug(3, "JBD2: commit phase 3\n");
795
796 while (!list_empty(&io_bufs)) {
797 struct buffer_head *bh = list_entry(io_bufs.prev,
798 struct buffer_head,
799 b_assoc_buffers);
800
801 wait_on_buffer(bh);
802 cond_resched();
803
804 if (unlikely(!buffer_uptodate(bh)))
805 err = -EIO;
806 jbd2_unfile_log_bh(bh);
807
808 /*
809 * The list contains temporary buffer heads created by
810 * jbd2_journal_write_metadata_buffer().
811 */
812 BUFFER_TRACE(bh, "dumping temporary bh");
813 __brelse(bh);
814 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
815 free_buffer_head(bh);
816
817 /* We also have to refile the corresponding shadowed buffer */
818 jh = commit_transaction->t_shadow_list->b_tprev;
819 bh = jh2bh(jh);
820 clear_buffer_jwrite(bh);
821 J_ASSERT_BH(bh, buffer_jbddirty(bh));
822 J_ASSERT_BH(bh, !buffer_shadow(bh));
823
824 /* The metadata is now released for reuse, but we need
825 to remember it against this transaction so that when
826 we finally commit, we can do any checkpointing
827 required. */
828 JBUFFER_TRACE(jh, "file as BJ_Forget");
829 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
830 JBUFFER_TRACE(jh, "brelse shadowed buffer");
831 __brelse(bh);
832 }
833
834 J_ASSERT (commit_transaction->t_shadow_list == NULL);
835
836 jbd_debug(3, "JBD2: commit phase 4\n");
837
838 /* Here we wait for the revoke record and descriptor record buffers */
839 while (!list_empty(&log_bufs)) {
840 struct buffer_head *bh;
841
842 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
843 wait_on_buffer(bh);
844 cond_resched();
845
846 if (unlikely(!buffer_uptodate(bh)))
847 err = -EIO;
848
849 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
850 clear_buffer_jwrite(bh);
851 jbd2_unfile_log_bh(bh);
852 __brelse(bh); /* One for getblk */
853 /* AKPM: bforget here */
854 }
855
856 if (err)
857 jbd2_journal_abort(journal, err);
858
859 jbd_debug(3, "JBD2: commit phase 5\n");
860 write_lock(&journal->j_state_lock);
861 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
862 commit_transaction->t_state = T_COMMIT_JFLUSH;
863 write_unlock(&journal->j_state_lock);
864
865 if (!jbd2_has_feature_async_commit(journal)) {
866 err = journal_submit_commit_record(journal, commit_transaction,
867 &cbh, crc32_sum);
868 if (err)
869 __jbd2_journal_abort_hard(journal);
870 }
871 if (cbh)
872 err = journal_wait_on_commit_record(journal, cbh);
873 if (jbd2_has_feature_async_commit(journal) &&
874 journal->j_flags & JBD2_BARRIER) {
875 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
876 }
877
878 if (err)
879 jbd2_journal_abort(journal, err);
880
881 /*
882 * Now disk caches for filesystem device are flushed so we are safe to
883 * erase checkpointed transactions from the log by updating journal
884 * superblock.
885 */
886 if (update_tail)
887 jbd2_update_log_tail(journal, first_tid, first_block);
888
889 /* End of a transaction! Finally, we can do checkpoint
890 processing: any buffers committed as a result of this
891 transaction can be removed from any checkpoint list it was on
892 before. */
893
894 jbd_debug(3, "JBD2: commit phase 6\n");
895
896 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
897 J_ASSERT(commit_transaction->t_buffers == NULL);
898 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
899 J_ASSERT(commit_transaction->t_shadow_list == NULL);
900
901restart_loop:
902 /*
903 * As there are other places (journal_unmap_buffer()) adding buffers
904 * to this list we have to be careful and hold the j_list_lock.
905 */
906 spin_lock(&journal->j_list_lock);
907 while (commit_transaction->t_forget) {
908 transaction_t *cp_transaction;
909 struct buffer_head *bh;
910 int try_to_free = 0;
911
912 jh = commit_transaction->t_forget;
913 spin_unlock(&journal->j_list_lock);
914 bh = jh2bh(jh);
915 /*
916 * Get a reference so that bh cannot be freed before we are
917 * done with it.
918 */
919 get_bh(bh);
920 jbd_lock_bh_state(bh);
921 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
922
923 /*
924 * If there is undo-protected committed data against
925 * this buffer, then we can remove it now. If it is a
926 * buffer needing such protection, the old frozen_data
927 * field now points to a committed version of the
928 * buffer, so rotate that field to the new committed
929 * data.
930 *
931 * Otherwise, we can just throw away the frozen data now.
932 *
933 * We also know that the frozen data has already fired
934 * its triggers if they exist, so we can clear that too.
935 */
936 if (jh->b_committed_data) {
937 jbd2_free(jh->b_committed_data, bh->b_size);
938 jh->b_committed_data = NULL;
939 if (jh->b_frozen_data) {
940 jh->b_committed_data = jh->b_frozen_data;
941 jh->b_frozen_data = NULL;
942 jh->b_frozen_triggers = NULL;
943 }
944 } else if (jh->b_frozen_data) {
945 jbd2_free(jh->b_frozen_data, bh->b_size);
946 jh->b_frozen_data = NULL;
947 jh->b_frozen_triggers = NULL;
948 }
949
950 spin_lock(&journal->j_list_lock);
951 cp_transaction = jh->b_cp_transaction;
952 if (cp_transaction) {
953 JBUFFER_TRACE(jh, "remove from old cp transaction");
954 cp_transaction->t_chp_stats.cs_dropped++;
955 __jbd2_journal_remove_checkpoint(jh);
956 }
957
958 /* Only re-checkpoint the buffer_head if it is marked
959 * dirty. If the buffer was added to the BJ_Forget list
960 * by jbd2_journal_forget, it may no longer be dirty and
961 * there's no point in keeping a checkpoint record for
962 * it. */
963
964 /*
965 * A buffer which has been freed while still being journaled by
966 * a previous transaction.
967 */
968 if (buffer_freed(bh)) {
969 /*
970 * If the running transaction is the one containing
971 * "add to orphan" operation (b_next_transaction !=
972 * NULL), we have to wait for that transaction to
973 * commit before we can really get rid of the buffer.
974 * So just clear b_modified to not confuse transaction
975 * credit accounting and refile the buffer to
976 * BJ_Forget of the running transaction. If the just
977 * committed transaction contains "add to orphan"
978 * operation, we can completely invalidate the buffer
979 * now. We are rather through in that since the
980 * buffer may be still accessible when blocksize <
981 * pagesize and it is attached to the last partial
982 * page.
983 */
984 jh->b_modified = 0;
985 if (!jh->b_next_transaction) {
986 clear_buffer_freed(bh);
987 clear_buffer_jbddirty(bh);
988 clear_buffer_mapped(bh);
989 clear_buffer_new(bh);
990 clear_buffer_req(bh);
991 bh->b_bdev = NULL;
992 }
993 }
994
995 if (buffer_jbddirty(bh)) {
996 JBUFFER_TRACE(jh, "add to new checkpointing trans");
997 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
998 if (is_journal_aborted(journal))
999 clear_buffer_jbddirty(bh);
1000 } else {
1001 J_ASSERT_BH(bh, !buffer_dirty(bh));
1002 /*
1003 * The buffer on BJ_Forget list and not jbddirty means
1004 * it has been freed by this transaction and hence it
1005 * could not have been reallocated until this
1006 * transaction has committed. *BUT* it could be
1007 * reallocated once we have written all the data to
1008 * disk and before we process the buffer on BJ_Forget
1009 * list.
1010 */
1011 if (!jh->b_next_transaction)
1012 try_to_free = 1;
1013 }
1014 JBUFFER_TRACE(jh, "refile or unfile buffer");
1015 __jbd2_journal_refile_buffer(jh);
1016 jbd_unlock_bh_state(bh);
1017 if (try_to_free)
1018 release_buffer_page(bh); /* Drops bh reference */
1019 else
1020 __brelse(bh);
1021 cond_resched_lock(&journal->j_list_lock);
1022 }
1023 spin_unlock(&journal->j_list_lock);
1024 /*
1025 * This is a bit sleazy. We use j_list_lock to protect transition
1026 * of a transaction into T_FINISHED state and calling
1027 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1028 * other checkpointing code processing the transaction...
1029 */
1030 write_lock(&journal->j_state_lock);
1031 spin_lock(&journal->j_list_lock);
1032 /*
1033 * Now recheck if some buffers did not get attached to the transaction
1034 * while the lock was dropped...
1035 */
1036 if (commit_transaction->t_forget) {
1037 spin_unlock(&journal->j_list_lock);
1038 write_unlock(&journal->j_state_lock);
1039 goto restart_loop;
1040 }
1041
1042 /* Add the transaction to the checkpoint list
1043 * __journal_remove_checkpoint() can not destroy transaction
1044 * under us because it is not marked as T_FINISHED yet */
1045 if (journal->j_checkpoint_transactions == NULL) {
1046 journal->j_checkpoint_transactions = commit_transaction;
1047 commit_transaction->t_cpnext = commit_transaction;
1048 commit_transaction->t_cpprev = commit_transaction;
1049 } else {
1050 commit_transaction->t_cpnext =
1051 journal->j_checkpoint_transactions;
1052 commit_transaction->t_cpprev =
1053 commit_transaction->t_cpnext->t_cpprev;
1054 commit_transaction->t_cpnext->t_cpprev =
1055 commit_transaction;
1056 commit_transaction->t_cpprev->t_cpnext =
1057 commit_transaction;
1058 }
1059 spin_unlock(&journal->j_list_lock);
1060
1061 /* Done with this transaction! */
1062
1063 jbd_debug(3, "JBD2: commit phase 7\n");
1064
1065 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1066
1067 commit_transaction->t_start = jiffies;
1068 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1069 commit_transaction->t_start);
1070
1071 /*
1072 * File the transaction statistics
1073 */
1074 stats.ts_tid = commit_transaction->t_tid;
1075 stats.run.rs_handle_count =
1076 atomic_read(&commit_transaction->t_handle_count);
1077 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1078 commit_transaction->t_tid, &stats.run);
1079 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1080
1081 commit_transaction->t_state = T_COMMIT_CALLBACK;
1082 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1083 journal->j_commit_sequence = commit_transaction->t_tid;
1084 journal->j_committing_transaction = NULL;
1085 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1086
1087 /*
1088 * weight the commit time higher than the average time so we don't
1089 * react too strongly to vast changes in the commit time
1090 */
1091 if (likely(journal->j_average_commit_time))
1092 journal->j_average_commit_time = (commit_time +
1093 journal->j_average_commit_time*3) / 4;
1094 else
1095 journal->j_average_commit_time = commit_time;
1096
1097 write_unlock(&journal->j_state_lock);
1098
1099 if (journal->j_commit_callback)
1100 journal->j_commit_callback(journal, commit_transaction);
1101
1102 trace_jbd2_end_commit(journal, commit_transaction);
1103 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1104 journal->j_commit_sequence, journal->j_tail_sequence);
1105
1106 write_lock(&journal->j_state_lock);
1107 spin_lock(&journal->j_list_lock);
1108 commit_transaction->t_state = T_FINISHED;
1109 /* Check if the transaction can be dropped now that we are finished */
1110 if (commit_transaction->t_checkpoint_list == NULL &&
1111 commit_transaction->t_checkpoint_io_list == NULL) {
1112 __jbd2_journal_drop_transaction(journal, commit_transaction);
1113 jbd2_journal_free_transaction(commit_transaction);
1114 }
1115 spin_unlock(&journal->j_list_lock);
1116 write_unlock(&journal->j_state_lock);
1117 wake_up(&journal->j_wait_done_commit);
1118
1119 /*
1120 * Calculate overall stats
1121 */
1122 spin_lock(&journal->j_history_lock);
1123 journal->j_stats.ts_tid++;
1124 journal->j_stats.ts_requested += stats.ts_requested;
1125 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1126 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1127 journal->j_stats.run.rs_running += stats.run.rs_running;
1128 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1129 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1130 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1131 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1132 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1133 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1134 spin_unlock(&journal->j_history_lock);
1135}
1/*
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_clear_bit();
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 page_cache_get(page);
85 __brelse(bh);
86 try_to_free_buffers(page);
87 unlock_page(page);
88 page_cache_release(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_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
101 return;
102
103 h = (struct commit_header *)(bh->b_data);
104 h->h_chksum_type = 0;
105 h->h_chksum_size = 0;
106 h->h_chksum[0] = 0;
107 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
108 h->h_chksum[0] = cpu_to_be32(csum);
109}
110
111/*
112 * Done it all: now submit the commit record. We should have
113 * cleaned up our previous buffers by now, so if we are in abort
114 * mode we can now just skip the rest of the journal write
115 * entirely.
116 *
117 * Returns 1 if the journal needs to be aborted or 0 on success
118 */
119static int journal_submit_commit_record(journal_t *journal,
120 transaction_t *commit_transaction,
121 struct buffer_head **cbh,
122 __u32 crc32_sum)
123{
124 struct commit_header *tmp;
125 struct buffer_head *bh;
126 int ret;
127 struct timespec now = current_kernel_time();
128
129 *cbh = NULL;
130
131 if (is_journal_aborted(journal))
132 return 0;
133
134 bh = jbd2_journal_get_descriptor_buffer(journal);
135 if (!bh)
136 return 1;
137
138 tmp = (struct commit_header *)bh->b_data;
139 tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
140 tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK);
141 tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
142 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
143 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
144
145 if (JBD2_HAS_COMPAT_FEATURE(journal,
146 JBD2_FEATURE_COMPAT_CHECKSUM)) {
147 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
148 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
149 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
150 }
151 jbd2_commit_block_csum_set(journal, bh);
152
153 BUFFER_TRACE(bh, "submit commit block");
154 lock_buffer(bh);
155 clear_buffer_dirty(bh);
156 set_buffer_uptodate(bh);
157 bh->b_end_io = journal_end_buffer_io_sync;
158
159 if (journal->j_flags & JBD2_BARRIER &&
160 !JBD2_HAS_INCOMPAT_FEATURE(journal,
161 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT))
162 ret = submit_bh(WRITE_SYNC | WRITE_FLUSH_FUA, bh);
163 else
164 ret = submit_bh(WRITE_SYNC, bh);
165
166 *cbh = bh;
167 return ret;
168}
169
170/*
171 * This function along with journal_submit_commit_record
172 * allows to write the commit record asynchronously.
173 */
174static int journal_wait_on_commit_record(journal_t *journal,
175 struct buffer_head *bh)
176{
177 int ret = 0;
178
179 clear_buffer_dirty(bh);
180 wait_on_buffer(bh);
181
182 if (unlikely(!buffer_uptodate(bh)))
183 ret = -EIO;
184 put_bh(bh); /* One for getblk() */
185
186 return ret;
187}
188
189/*
190 * write the filemap data using writepage() address_space_operations.
191 * We don't do block allocation here even for delalloc. We don't
192 * use writepages() because with dealyed allocation we may be doing
193 * block allocation in writepages().
194 */
195static int journal_submit_inode_data_buffers(struct address_space *mapping)
196{
197 int ret;
198 struct writeback_control wbc = {
199 .sync_mode = WB_SYNC_ALL,
200 .nr_to_write = mapping->nrpages * 2,
201 .range_start = 0,
202 .range_end = i_size_read(mapping->host),
203 };
204
205 ret = generic_writepages(mapping, &wbc);
206 return ret;
207}
208
209/*
210 * Submit all the data buffers of inode associated with the transaction to
211 * disk.
212 *
213 * We are in a committing transaction. Therefore no new inode can be added to
214 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
215 * operate on from being released while we write out pages.
216 */
217static int journal_submit_data_buffers(journal_t *journal,
218 transaction_t *commit_transaction)
219{
220 struct jbd2_inode *jinode;
221 int err, ret = 0;
222 struct address_space *mapping;
223
224 spin_lock(&journal->j_list_lock);
225 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
226 mapping = jinode->i_vfs_inode->i_mapping;
227 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
228 spin_unlock(&journal->j_list_lock);
229 /*
230 * submit the inode data buffers. We use writepage
231 * instead of writepages. Because writepages can do
232 * block allocation with delalloc. We need to write
233 * only allocated blocks here.
234 */
235 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
236 err = journal_submit_inode_data_buffers(mapping);
237 if (!ret)
238 ret = err;
239 spin_lock(&journal->j_list_lock);
240 J_ASSERT(jinode->i_transaction == commit_transaction);
241 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
242 smp_mb__after_clear_bit();
243 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
244 }
245 spin_unlock(&journal->j_list_lock);
246 return ret;
247}
248
249/*
250 * Wait for data submitted for writeout, refile inodes to proper
251 * transaction if needed.
252 *
253 */
254static int journal_finish_inode_data_buffers(journal_t *journal,
255 transaction_t *commit_transaction)
256{
257 struct jbd2_inode *jinode, *next_i;
258 int err, ret = 0;
259
260 /* For locking, see the comment in journal_submit_data_buffers() */
261 spin_lock(&journal->j_list_lock);
262 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
263 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
264 spin_unlock(&journal->j_list_lock);
265 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
266 if (err) {
267 /*
268 * Because AS_EIO is cleared by
269 * filemap_fdatawait_range(), set it again so
270 * that user process can get -EIO from fsync().
271 */
272 set_bit(AS_EIO,
273 &jinode->i_vfs_inode->i_mapping->flags);
274
275 if (!ret)
276 ret = err;
277 }
278 spin_lock(&journal->j_list_lock);
279 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
280 smp_mb__after_clear_bit();
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(int tag_bytes, journal_block_tag_t *tag,
317 unsigned long long block)
318{
319 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
320 if (tag_bytes > JBD2_TAG_SIZE32)
321 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
322}
323
324static void jbd2_descr_block_csum_set(journal_t *j,
325 struct buffer_head *bh)
326{
327 struct jbd2_journal_block_tail *tail;
328 __u32 csum;
329
330 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
331 return;
332
333 tail = (struct jbd2_journal_block_tail *)(bh->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, bh->b_data, j->j_blocksize);
337 tail->t_checksum = cpu_to_be32(csum);
338}
339
340static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
341 struct buffer_head *bh, __u32 sequence)
342{
343 struct page *page = bh->b_page;
344 __u8 *addr;
345 __u32 csum32;
346 __be32 seq;
347
348 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
349 return;
350
351 seq = cpu_to_be32(sequence);
352 addr = kmap_atomic(page);
353 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
354 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
355 bh->b_size);
356 kunmap_atomic(addr);
357
358 /* We only have space to store the lower 16 bits of the crc32c. */
359 tag->t_checksum = cpu_to_be16(csum32);
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;
372 struct buffer_head *descriptor;
373 struct buffer_head **wbuf = journal->j_wbuf;
374 int bufs;
375 int flags;
376 int err;
377 unsigned long long blocknr;
378 ktime_t start_time;
379 u64 commit_time;
380 char *tagp = NULL;
381 journal_header_t *header;
382 journal_block_tag_t *tag = NULL;
383 int space_left = 0;
384 int first_tag = 0;
385 int tag_flag;
386 int i;
387 int tag_bytes = journal_tag_bytes(journal);
388 struct buffer_head *cbh = NULL; /* For transactional checksums */
389 __u32 crc32_sum = ~0;
390 struct blk_plug plug;
391 /* Tail of the journal */
392 unsigned long first_block;
393 tid_t first_tid;
394 int update_tail;
395 int csum_size = 0;
396 LIST_HEAD(io_bufs);
397 LIST_HEAD(log_bufs);
398
399 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
400 csum_size = sizeof(struct jbd2_journal_block_tail);
401
402 /*
403 * First job: lock down the current transaction and wait for
404 * all outstanding updates to complete.
405 */
406
407 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
408 if (journal->j_flags & JBD2_FLUSHED) {
409 jbd_debug(3, "super block updated\n");
410 mutex_lock(&journal->j_checkpoint_mutex);
411 /*
412 * We hold j_checkpoint_mutex so tail cannot change under us.
413 * We don't need any special data guarantees for writing sb
414 * since journal is empty and it is ok for write to be
415 * flushed only with transaction commit.
416 */
417 jbd2_journal_update_sb_log_tail(journal,
418 journal->j_tail_sequence,
419 journal->j_tail,
420 WRITE_SYNC);
421 mutex_unlock(&journal->j_checkpoint_mutex);
422 } else {
423 jbd_debug(3, "superblock not updated\n");
424 }
425
426 J_ASSERT(journal->j_running_transaction != NULL);
427 J_ASSERT(journal->j_committing_transaction == NULL);
428
429 commit_transaction = journal->j_running_transaction;
430
431 trace_jbd2_start_commit(journal, commit_transaction);
432 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
433 commit_transaction->t_tid);
434
435 write_lock(&journal->j_state_lock);
436 J_ASSERT(commit_transaction->t_state == T_RUNNING);
437 commit_transaction->t_state = T_LOCKED;
438
439 trace_jbd2_commit_locking(journal, commit_transaction);
440 stats.run.rs_wait = commit_transaction->t_max_wait;
441 stats.run.rs_request_delay = 0;
442 stats.run.rs_locked = jiffies;
443 if (commit_transaction->t_requested)
444 stats.run.rs_request_delay =
445 jbd2_time_diff(commit_transaction->t_requested,
446 stats.run.rs_locked);
447 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
448 stats.run.rs_locked);
449
450 spin_lock(&commit_transaction->t_handle_lock);
451 while (atomic_read(&commit_transaction->t_updates)) {
452 DEFINE_WAIT(wait);
453
454 prepare_to_wait(&journal->j_wait_updates, &wait,
455 TASK_UNINTERRUPTIBLE);
456 if (atomic_read(&commit_transaction->t_updates)) {
457 spin_unlock(&commit_transaction->t_handle_lock);
458 write_unlock(&journal->j_state_lock);
459 schedule();
460 write_lock(&journal->j_state_lock);
461 spin_lock(&commit_transaction->t_handle_lock);
462 }
463 finish_wait(&journal->j_wait_updates, &wait);
464 }
465 spin_unlock(&commit_transaction->t_handle_lock);
466
467 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
468 journal->j_max_transaction_buffers);
469
470 /*
471 * First thing we are allowed to do is to discard any remaining
472 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
473 * that there are no such buffers: if a large filesystem
474 * operation like a truncate needs to split itself over multiple
475 * transactions, then it may try to do a jbd2_journal_restart() while
476 * there are still BJ_Reserved buffers outstanding. These must
477 * be released cleanly from the current transaction.
478 *
479 * In this case, the filesystem must still reserve write access
480 * again before modifying the buffer in the new transaction, but
481 * we do not require it to remember exactly which old buffers it
482 * has reserved. This is consistent with the existing behaviour
483 * that multiple jbd2_journal_get_write_access() calls to the same
484 * buffer are perfectly permissible.
485 */
486 while (commit_transaction->t_reserved_list) {
487 jh = commit_transaction->t_reserved_list;
488 JBUFFER_TRACE(jh, "reserved, unused: refile");
489 /*
490 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
491 * leave undo-committed data.
492 */
493 if (jh->b_committed_data) {
494 struct buffer_head *bh = jh2bh(jh);
495
496 jbd_lock_bh_state(bh);
497 jbd2_free(jh->b_committed_data, bh->b_size);
498 jh->b_committed_data = NULL;
499 jbd_unlock_bh_state(bh);
500 }
501 jbd2_journal_refile_buffer(journal, jh);
502 }
503
504 /*
505 * Now try to drop any written-back buffers from the journal's
506 * checkpoint lists. We do this *before* commit because it potentially
507 * frees some memory
508 */
509 spin_lock(&journal->j_list_lock);
510 __jbd2_journal_clean_checkpoint_list(journal);
511 spin_unlock(&journal->j_list_lock);
512
513 jbd_debug(3, "JBD2: commit phase 1\n");
514
515 /*
516 * Clear revoked flag to reflect there is no revoked buffers
517 * in the next transaction which is going to be started.
518 */
519 jbd2_clear_buffer_revoked_flags(journal);
520
521 /*
522 * Switch to a new revoke table.
523 */
524 jbd2_journal_switch_revoke_table(journal);
525
526 /*
527 * Reserved credits cannot be claimed anymore, free them
528 */
529 atomic_sub(atomic_read(&journal->j_reserved_credits),
530 &commit_transaction->t_outstanding_credits);
531
532 trace_jbd2_commit_flushing(journal, commit_transaction);
533 stats.run.rs_flushing = jiffies;
534 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
535 stats.run.rs_flushing);
536
537 commit_transaction->t_state = T_FLUSH;
538 journal->j_committing_transaction = commit_transaction;
539 journal->j_running_transaction = NULL;
540 start_time = ktime_get();
541 commit_transaction->t_log_start = journal->j_head;
542 wake_up(&journal->j_wait_transaction_locked);
543 write_unlock(&journal->j_state_lock);
544
545 jbd_debug(3, "JBD2: commit phase 2a\n");
546
547 /*
548 * Now start flushing things to disk, in the order they appear
549 * on the transaction lists. Data blocks go first.
550 */
551 err = journal_submit_data_buffers(journal, commit_transaction);
552 if (err)
553 jbd2_journal_abort(journal, err);
554
555 blk_start_plug(&plug);
556 jbd2_journal_write_revoke_records(journal, commit_transaction,
557 &log_bufs, WRITE_SYNC);
558
559 jbd_debug(3, "JBD2: commit phase 2b\n");
560
561 /*
562 * Way to go: we have now written out all of the data for a
563 * transaction! Now comes the tricky part: we need to write out
564 * metadata. Loop over the transaction's entire buffer list:
565 */
566 write_lock(&journal->j_state_lock);
567 commit_transaction->t_state = T_COMMIT;
568 write_unlock(&journal->j_state_lock);
569
570 trace_jbd2_commit_logging(journal, commit_transaction);
571 stats.run.rs_logging = jiffies;
572 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
573 stats.run.rs_logging);
574 stats.run.rs_blocks =
575 atomic_read(&commit_transaction->t_outstanding_credits);
576 stats.run.rs_blocks_logged = 0;
577
578 J_ASSERT(commit_transaction->t_nr_buffers <=
579 atomic_read(&commit_transaction->t_outstanding_credits));
580
581 err = 0;
582 bufs = 0;
583 descriptor = NULL;
584 while (commit_transaction->t_buffers) {
585
586 /* Find the next buffer to be journaled... */
587
588 jh = commit_transaction->t_buffers;
589
590 /* If we're in abort mode, we just un-journal the buffer and
591 release it. */
592
593 if (is_journal_aborted(journal)) {
594 clear_buffer_jbddirty(jh2bh(jh));
595 JBUFFER_TRACE(jh, "journal is aborting: refile");
596 jbd2_buffer_abort_trigger(jh,
597 jh->b_frozen_data ?
598 jh->b_frozen_triggers :
599 jh->b_triggers);
600 jbd2_journal_refile_buffer(journal, jh);
601 /* If that was the last one, we need to clean up
602 * any descriptor buffers which may have been
603 * already allocated, even if we are now
604 * aborting. */
605 if (!commit_transaction->t_buffers)
606 goto start_journal_io;
607 continue;
608 }
609
610 /* Make sure we have a descriptor block in which to
611 record the metadata buffer. */
612
613 if (!descriptor) {
614 J_ASSERT (bufs == 0);
615
616 jbd_debug(4, "JBD2: get descriptor\n");
617
618 descriptor = jbd2_journal_get_descriptor_buffer(journal);
619 if (!descriptor) {
620 jbd2_journal_abort(journal, -EIO);
621 continue;
622 }
623
624 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
625 (unsigned long long)descriptor->b_blocknr,
626 descriptor->b_data);
627 header = (journal_header_t *)descriptor->b_data;
628 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
629 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK);
630 header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
631
632 tagp = &descriptor->b_data[sizeof(journal_header_t)];
633 space_left = descriptor->b_size -
634 sizeof(journal_header_t);
635 first_tag = 1;
636 set_buffer_jwrite(descriptor);
637 set_buffer_dirty(descriptor);
638 wbuf[bufs++] = descriptor;
639
640 /* Record it so that we can wait for IO
641 completion later */
642 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
643 jbd2_file_log_bh(&log_bufs, descriptor);
644 }
645
646 /* Where is the buffer to be written? */
647
648 err = jbd2_journal_next_log_block(journal, &blocknr);
649 /* If the block mapping failed, just abandon the buffer
650 and repeat this loop: we'll fall into the
651 refile-on-abort condition above. */
652 if (err) {
653 jbd2_journal_abort(journal, err);
654 continue;
655 }
656
657 /*
658 * start_this_handle() uses t_outstanding_credits to determine
659 * the free space in the log, but this counter is changed
660 * by jbd2_journal_next_log_block() also.
661 */
662 atomic_dec(&commit_transaction->t_outstanding_credits);
663
664 /* Bump b_count to prevent truncate from stumbling over
665 the shadowed buffer! @@@ This can go if we ever get
666 rid of the shadow pairing of buffers. */
667 atomic_inc(&jh2bh(jh)->b_count);
668
669 /*
670 * Make a temporary IO buffer with which to write it out
671 * (this will requeue the metadata buffer to BJ_Shadow).
672 */
673 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
674 JBUFFER_TRACE(jh, "ph3: write metadata");
675 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
676 jh, &wbuf[bufs], blocknr);
677 if (flags < 0) {
678 jbd2_journal_abort(journal, flags);
679 continue;
680 }
681 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
682
683 /* Record the new block's tag in the current descriptor
684 buffer */
685
686 tag_flag = 0;
687 if (flags & 1)
688 tag_flag |= JBD2_FLAG_ESCAPE;
689 if (!first_tag)
690 tag_flag |= JBD2_FLAG_SAME_UUID;
691
692 tag = (journal_block_tag_t *) tagp;
693 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr);
694 tag->t_flags = cpu_to_be16(tag_flag);
695 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
696 commit_transaction->t_tid);
697 tagp += tag_bytes;
698 space_left -= tag_bytes;
699 bufs++;
700
701 if (first_tag) {
702 memcpy (tagp, journal->j_uuid, 16);
703 tagp += 16;
704 space_left -= 16;
705 first_tag = 0;
706 }
707
708 /* If there's no more to do, or if the descriptor is full,
709 let the IO rip! */
710
711 if (bufs == journal->j_wbufsize ||
712 commit_transaction->t_buffers == NULL ||
713 space_left < tag_bytes + 16 + csum_size) {
714
715 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
716
717 /* Write an end-of-descriptor marker before
718 submitting the IOs. "tag" still points to
719 the last tag we set up. */
720
721 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
722
723 jbd2_descr_block_csum_set(journal, descriptor);
724start_journal_io:
725 for (i = 0; i < bufs; i++) {
726 struct buffer_head *bh = wbuf[i];
727 /*
728 * Compute checksum.
729 */
730 if (JBD2_HAS_COMPAT_FEATURE(journal,
731 JBD2_FEATURE_COMPAT_CHECKSUM)) {
732 crc32_sum =
733 jbd2_checksum_data(crc32_sum, bh);
734 }
735
736 lock_buffer(bh);
737 clear_buffer_dirty(bh);
738 set_buffer_uptodate(bh);
739 bh->b_end_io = journal_end_buffer_io_sync;
740 submit_bh(WRITE_SYNC, bh);
741 }
742 cond_resched();
743 stats.run.rs_blocks_logged += bufs;
744
745 /* Force a new descriptor to be generated next
746 time round the loop. */
747 descriptor = NULL;
748 bufs = 0;
749 }
750 }
751
752 err = journal_finish_inode_data_buffers(journal, commit_transaction);
753 if (err) {
754 printk(KERN_WARNING
755 "JBD2: Detected IO errors while flushing file data "
756 "on %s\n", journal->j_devname);
757 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
758 jbd2_journal_abort(journal, err);
759 err = 0;
760 }
761
762 /*
763 * Get current oldest transaction in the log before we issue flush
764 * to the filesystem device. After the flush we can be sure that
765 * blocks of all older transactions are checkpointed to persistent
766 * storage and we will be safe to update journal start in the
767 * superblock with the numbers we get here.
768 */
769 update_tail =
770 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
771
772 write_lock(&journal->j_state_lock);
773 if (update_tail) {
774 long freed = first_block - journal->j_tail;
775
776 if (first_block < journal->j_tail)
777 freed += journal->j_last - journal->j_first;
778 /* Update tail only if we free significant amount of space */
779 if (freed < journal->j_maxlen / 4)
780 update_tail = 0;
781 }
782 J_ASSERT(commit_transaction->t_state == T_COMMIT);
783 commit_transaction->t_state = T_COMMIT_DFLUSH;
784 write_unlock(&journal->j_state_lock);
785
786 /*
787 * If the journal is not located on the file system device,
788 * then we must flush the file system device before we issue
789 * the commit record
790 */
791 if (commit_transaction->t_need_data_flush &&
792 (journal->j_fs_dev != journal->j_dev) &&
793 (journal->j_flags & JBD2_BARRIER))
794 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
795
796 /* Done it all: now write the commit record asynchronously. */
797 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
798 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
799 err = journal_submit_commit_record(journal, commit_transaction,
800 &cbh, crc32_sum);
801 if (err)
802 __jbd2_journal_abort_hard(journal);
803 }
804
805 blk_finish_plug(&plug);
806
807 /* Lo and behold: we have just managed to send a transaction to
808 the log. Before we can commit it, wait for the IO so far to
809 complete. Control buffers being written are on the
810 transaction's t_log_list queue, and metadata buffers are on
811 the io_bufs list.
812
813 Wait for the buffers in reverse order. That way we are
814 less likely to be woken up until all IOs have completed, and
815 so we incur less scheduling load.
816 */
817
818 jbd_debug(3, "JBD2: commit phase 3\n");
819
820 while (!list_empty(&io_bufs)) {
821 struct buffer_head *bh = list_entry(io_bufs.prev,
822 struct buffer_head,
823 b_assoc_buffers);
824
825 wait_on_buffer(bh);
826 cond_resched();
827
828 if (unlikely(!buffer_uptodate(bh)))
829 err = -EIO;
830 jbd2_unfile_log_bh(bh);
831
832 /*
833 * The list contains temporary buffer heads created by
834 * jbd2_journal_write_metadata_buffer().
835 */
836 BUFFER_TRACE(bh, "dumping temporary bh");
837 __brelse(bh);
838 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
839 free_buffer_head(bh);
840
841 /* We also have to refile the corresponding shadowed buffer */
842 jh = commit_transaction->t_shadow_list->b_tprev;
843 bh = jh2bh(jh);
844 clear_buffer_jwrite(bh);
845 J_ASSERT_BH(bh, buffer_jbddirty(bh));
846 J_ASSERT_BH(bh, !buffer_shadow(bh));
847
848 /* The metadata is now released for reuse, but we need
849 to remember it against this transaction so that when
850 we finally commit, we can do any checkpointing
851 required. */
852 JBUFFER_TRACE(jh, "file as BJ_Forget");
853 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
854 JBUFFER_TRACE(jh, "brelse shadowed buffer");
855 __brelse(bh);
856 }
857
858 J_ASSERT (commit_transaction->t_shadow_list == NULL);
859
860 jbd_debug(3, "JBD2: commit phase 4\n");
861
862 /* Here we wait for the revoke record and descriptor record buffers */
863 while (!list_empty(&log_bufs)) {
864 struct buffer_head *bh;
865
866 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
867 wait_on_buffer(bh);
868 cond_resched();
869
870 if (unlikely(!buffer_uptodate(bh)))
871 err = -EIO;
872
873 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
874 clear_buffer_jwrite(bh);
875 jbd2_unfile_log_bh(bh);
876 __brelse(bh); /* One for getblk */
877 /* AKPM: bforget here */
878 }
879
880 if (err)
881 jbd2_journal_abort(journal, err);
882
883 jbd_debug(3, "JBD2: commit phase 5\n");
884 write_lock(&journal->j_state_lock);
885 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
886 commit_transaction->t_state = T_COMMIT_JFLUSH;
887 write_unlock(&journal->j_state_lock);
888
889 if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
890 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
891 err = journal_submit_commit_record(journal, commit_transaction,
892 &cbh, crc32_sum);
893 if (err)
894 __jbd2_journal_abort_hard(journal);
895 }
896 if (cbh)
897 err = journal_wait_on_commit_record(journal, cbh);
898 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
899 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) &&
900 journal->j_flags & JBD2_BARRIER) {
901 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
902 }
903
904 if (err)
905 jbd2_journal_abort(journal, err);
906
907 /*
908 * Now disk caches for filesystem device are flushed so we are safe to
909 * erase checkpointed transactions from the log by updating journal
910 * superblock.
911 */
912 if (update_tail)
913 jbd2_update_log_tail(journal, first_tid, first_block);
914
915 /* End of a transaction! Finally, we can do checkpoint
916 processing: any buffers committed as a result of this
917 transaction can be removed from any checkpoint list it was on
918 before. */
919
920 jbd_debug(3, "JBD2: commit phase 6\n");
921
922 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
923 J_ASSERT(commit_transaction->t_buffers == NULL);
924 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
925 J_ASSERT(commit_transaction->t_shadow_list == NULL);
926
927restart_loop:
928 /*
929 * As there are other places (journal_unmap_buffer()) adding buffers
930 * to this list we have to be careful and hold the j_list_lock.
931 */
932 spin_lock(&journal->j_list_lock);
933 while (commit_transaction->t_forget) {
934 transaction_t *cp_transaction;
935 struct buffer_head *bh;
936 int try_to_free = 0;
937
938 jh = commit_transaction->t_forget;
939 spin_unlock(&journal->j_list_lock);
940 bh = jh2bh(jh);
941 /*
942 * Get a reference so that bh cannot be freed before we are
943 * done with it.
944 */
945 get_bh(bh);
946 jbd_lock_bh_state(bh);
947 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
948
949 /*
950 * If there is undo-protected committed data against
951 * this buffer, then we can remove it now. If it is a
952 * buffer needing such protection, the old frozen_data
953 * field now points to a committed version of the
954 * buffer, so rotate that field to the new committed
955 * data.
956 *
957 * Otherwise, we can just throw away the frozen data now.
958 *
959 * We also know that the frozen data has already fired
960 * its triggers if they exist, so we can clear that too.
961 */
962 if (jh->b_committed_data) {
963 jbd2_free(jh->b_committed_data, bh->b_size);
964 jh->b_committed_data = NULL;
965 if (jh->b_frozen_data) {
966 jh->b_committed_data = jh->b_frozen_data;
967 jh->b_frozen_data = NULL;
968 jh->b_frozen_triggers = NULL;
969 }
970 } else if (jh->b_frozen_data) {
971 jbd2_free(jh->b_frozen_data, bh->b_size);
972 jh->b_frozen_data = NULL;
973 jh->b_frozen_triggers = NULL;
974 }
975
976 spin_lock(&journal->j_list_lock);
977 cp_transaction = jh->b_cp_transaction;
978 if (cp_transaction) {
979 JBUFFER_TRACE(jh, "remove from old cp transaction");
980 cp_transaction->t_chp_stats.cs_dropped++;
981 __jbd2_journal_remove_checkpoint(jh);
982 }
983
984 /* Only re-checkpoint the buffer_head if it is marked
985 * dirty. If the buffer was added to the BJ_Forget list
986 * by jbd2_journal_forget, it may no longer be dirty and
987 * there's no point in keeping a checkpoint record for
988 * it. */
989
990 /*
991 * A buffer which has been freed while still being journaled by
992 * a previous transaction.
993 */
994 if (buffer_freed(bh)) {
995 /*
996 * If the running transaction is the one containing
997 * "add to orphan" operation (b_next_transaction !=
998 * NULL), we have to wait for that transaction to
999 * commit before we can really get rid of the buffer.
1000 * So just clear b_modified to not confuse transaction
1001 * credit accounting and refile the buffer to
1002 * BJ_Forget of the running transaction. If the just
1003 * committed transaction contains "add to orphan"
1004 * operation, we can completely invalidate the buffer
1005 * now. We are rather through in that since the
1006 * buffer may be still accessible when blocksize <
1007 * pagesize and it is attached to the last partial
1008 * page.
1009 */
1010 jh->b_modified = 0;
1011 if (!jh->b_next_transaction) {
1012 clear_buffer_freed(bh);
1013 clear_buffer_jbddirty(bh);
1014 clear_buffer_mapped(bh);
1015 clear_buffer_new(bh);
1016 clear_buffer_req(bh);
1017 bh->b_bdev = NULL;
1018 }
1019 }
1020
1021 if (buffer_jbddirty(bh)) {
1022 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1023 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1024 if (is_journal_aborted(journal))
1025 clear_buffer_jbddirty(bh);
1026 } else {
1027 J_ASSERT_BH(bh, !buffer_dirty(bh));
1028 /*
1029 * The buffer on BJ_Forget list and not jbddirty means
1030 * it has been freed by this transaction and hence it
1031 * could not have been reallocated until this
1032 * transaction has committed. *BUT* it could be
1033 * reallocated once we have written all the data to
1034 * disk and before we process the buffer on BJ_Forget
1035 * list.
1036 */
1037 if (!jh->b_next_transaction)
1038 try_to_free = 1;
1039 }
1040 JBUFFER_TRACE(jh, "refile or unfile buffer");
1041 __jbd2_journal_refile_buffer(jh);
1042 jbd_unlock_bh_state(bh);
1043 if (try_to_free)
1044 release_buffer_page(bh); /* Drops bh reference */
1045 else
1046 __brelse(bh);
1047 cond_resched_lock(&journal->j_list_lock);
1048 }
1049 spin_unlock(&journal->j_list_lock);
1050 /*
1051 * This is a bit sleazy. We use j_list_lock to protect transition
1052 * of a transaction into T_FINISHED state and calling
1053 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1054 * other checkpointing code processing the transaction...
1055 */
1056 write_lock(&journal->j_state_lock);
1057 spin_lock(&journal->j_list_lock);
1058 /*
1059 * Now recheck if some buffers did not get attached to the transaction
1060 * while the lock was dropped...
1061 */
1062 if (commit_transaction->t_forget) {
1063 spin_unlock(&journal->j_list_lock);
1064 write_unlock(&journal->j_state_lock);
1065 goto restart_loop;
1066 }
1067
1068 /* Add the transaction to the checkpoint list
1069 * __journal_remove_checkpoint() can not destroy transaction
1070 * under us because it is not marked as T_FINISHED yet */
1071 if (journal->j_checkpoint_transactions == NULL) {
1072 journal->j_checkpoint_transactions = commit_transaction;
1073 commit_transaction->t_cpnext = commit_transaction;
1074 commit_transaction->t_cpprev = commit_transaction;
1075 } else {
1076 commit_transaction->t_cpnext =
1077 journal->j_checkpoint_transactions;
1078 commit_transaction->t_cpprev =
1079 commit_transaction->t_cpnext->t_cpprev;
1080 commit_transaction->t_cpnext->t_cpprev =
1081 commit_transaction;
1082 commit_transaction->t_cpprev->t_cpnext =
1083 commit_transaction;
1084 }
1085 spin_unlock(&journal->j_list_lock);
1086
1087 /* Done with this transaction! */
1088
1089 jbd_debug(3, "JBD2: commit phase 7\n");
1090
1091 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1092
1093 commit_transaction->t_start = jiffies;
1094 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1095 commit_transaction->t_start);
1096
1097 /*
1098 * File the transaction statistics
1099 */
1100 stats.ts_tid = commit_transaction->t_tid;
1101 stats.run.rs_handle_count =
1102 atomic_read(&commit_transaction->t_handle_count);
1103 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1104 commit_transaction->t_tid, &stats.run);
1105 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1106
1107 commit_transaction->t_state = T_COMMIT_CALLBACK;
1108 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1109 journal->j_commit_sequence = commit_transaction->t_tid;
1110 journal->j_committing_transaction = NULL;
1111 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1112
1113 /*
1114 * weight the commit time higher than the average time so we don't
1115 * react too strongly to vast changes in the commit time
1116 */
1117 if (likely(journal->j_average_commit_time))
1118 journal->j_average_commit_time = (commit_time +
1119 journal->j_average_commit_time*3) / 4;
1120 else
1121 journal->j_average_commit_time = commit_time;
1122
1123 write_unlock(&journal->j_state_lock);
1124
1125 if (journal->j_commit_callback)
1126 journal->j_commit_callback(journal, commit_transaction);
1127
1128 trace_jbd2_end_commit(journal, commit_transaction);
1129 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1130 journal->j_commit_sequence, journal->j_tail_sequence);
1131
1132 write_lock(&journal->j_state_lock);
1133 spin_lock(&journal->j_list_lock);
1134 commit_transaction->t_state = T_FINISHED;
1135 /* Check if the transaction can be dropped now that we are finished */
1136 if (commit_transaction->t_checkpoint_list == NULL &&
1137 commit_transaction->t_checkpoint_io_list == NULL) {
1138 __jbd2_journal_drop_transaction(journal, commit_transaction);
1139 jbd2_journal_free_transaction(commit_transaction);
1140 }
1141 spin_unlock(&journal->j_list_lock);
1142 write_unlock(&journal->j_state_lock);
1143 wake_up(&journal->j_wait_done_commit);
1144
1145 /*
1146 * Calculate overall stats
1147 */
1148 spin_lock(&journal->j_history_lock);
1149 journal->j_stats.ts_tid++;
1150 journal->j_stats.ts_requested += stats.ts_requested;
1151 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1152 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1153 journal->j_stats.run.rs_running += stats.run.rs_running;
1154 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1155 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1156 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1157 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1158 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1159 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1160 spin_unlock(&journal->j_history_lock);
1161}