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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 * 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}