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1/*
2 * linux/fs/jbd2/commit.c
3 *
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
5 *
6 * Copyright 1998 Red Hat corp --- All Rights Reserved
7 *
8 * This file is part of the Linux kernel and is made available under
9 * the terms of the GNU General Public License, version 2, or at your
10 * option, any later version, incorporated herein by reference.
11 *
12 * Journal commit routines for the generic filesystem journaling code;
13 * part of the ext2fs journaling system.
14 */
15
16#include <linux/time.h>
17#include <linux/fs.h>
18#include <linux/jbd2.h>
19#include <linux/errno.h>
20#include <linux/slab.h>
21#include <linux/mm.h>
22#include <linux/pagemap.h>
23#include <linux/jiffies.h>
24#include <linux/crc32.h>
25#include <linux/writeback.h>
26#include <linux/backing-dev.h>
27#include <linux/bio.h>
28#include <linux/blkdev.h>
29#include <linux/bitops.h>
30#include <trace/events/jbd2.h>
31#include <asm/system.h>
32
33/*
34 * Default IO end handler for temporary BJ_IO buffer_heads.
35 */
36static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
37{
38 BUFFER_TRACE(bh, "");
39 if (uptodate)
40 set_buffer_uptodate(bh);
41 else
42 clear_buffer_uptodate(bh);
43 unlock_buffer(bh);
44}
45
46/*
47 * When an ext4 file is truncated, it is possible that some pages are not
48 * successfully freed, because they are attached to a committing transaction.
49 * After the transaction commits, these pages are left on the LRU, with no
50 * ->mapping, and with attached buffers. These pages are trivially reclaimable
51 * by the VM, but their apparent absence upsets the VM accounting, and it makes
52 * the numbers in /proc/meminfo look odd.
53 *
54 * So here, we have a buffer which has just come off the forget list. Look to
55 * see if we can strip all buffers from the backing page.
56 *
57 * Called under lock_journal(), and possibly under journal_datalist_lock. The
58 * caller provided us with a ref against the buffer, and we drop that here.
59 */
60static void release_buffer_page(struct buffer_head *bh)
61{
62 struct page *page;
63
64 if (buffer_dirty(bh))
65 goto nope;
66 if (atomic_read(&bh->b_count) != 1)
67 goto nope;
68 page = bh->b_page;
69 if (!page)
70 goto nope;
71 if (page->mapping)
72 goto nope;
73
74 /* OK, it's a truncated page */
75 if (!trylock_page(page))
76 goto nope;
77
78 page_cache_get(page);
79 __brelse(bh);
80 try_to_free_buffers(page);
81 unlock_page(page);
82 page_cache_release(page);
83 return;
84
85nope:
86 __brelse(bh);
87}
88
89/*
90 * Done it all: now submit the commit record. We should have
91 * cleaned up our previous buffers by now, so if we are in abort
92 * mode we can now just skip the rest of the journal write
93 * entirely.
94 *
95 * Returns 1 if the journal needs to be aborted or 0 on success
96 */
97static int journal_submit_commit_record(journal_t *journal,
98 transaction_t *commit_transaction,
99 struct buffer_head **cbh,
100 __u32 crc32_sum)
101{
102 struct journal_head *descriptor;
103 struct commit_header *tmp;
104 struct buffer_head *bh;
105 int ret;
106 struct timespec now = current_kernel_time();
107
108 *cbh = NULL;
109
110 if (is_journal_aborted(journal))
111 return 0;
112
113 descriptor = jbd2_journal_get_descriptor_buffer(journal);
114 if (!descriptor)
115 return 1;
116
117 bh = jh2bh(descriptor);
118
119 tmp = (struct commit_header *)bh->b_data;
120 tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
121 tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK);
122 tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
123 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
124 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
125
126 if (JBD2_HAS_COMPAT_FEATURE(journal,
127 JBD2_FEATURE_COMPAT_CHECKSUM)) {
128 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
129 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
130 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
131 }
132
133 JBUFFER_TRACE(descriptor, "submit commit block");
134 lock_buffer(bh);
135 clear_buffer_dirty(bh);
136 set_buffer_uptodate(bh);
137 bh->b_end_io = journal_end_buffer_io_sync;
138
139 if (journal->j_flags & JBD2_BARRIER &&
140 !JBD2_HAS_INCOMPAT_FEATURE(journal,
141 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT))
142 ret = submit_bh(WRITE_SYNC | WRITE_FLUSH_FUA, bh);
143 else
144 ret = submit_bh(WRITE_SYNC, bh);
145
146 *cbh = bh;
147 return ret;
148}
149
150/*
151 * This function along with journal_submit_commit_record
152 * allows to write the commit record asynchronously.
153 */
154static int journal_wait_on_commit_record(journal_t *journal,
155 struct buffer_head *bh)
156{
157 int ret = 0;
158
159 clear_buffer_dirty(bh);
160 wait_on_buffer(bh);
161
162 if (unlikely(!buffer_uptodate(bh)))
163 ret = -EIO;
164 put_bh(bh); /* One for getblk() */
165 jbd2_journal_put_journal_head(bh2jh(bh));
166
167 return ret;
168}
169
170/*
171 * write the filemap data using writepage() address_space_operations.
172 * We don't do block allocation here even for delalloc. We don't
173 * use writepages() because with dealyed allocation we may be doing
174 * block allocation in writepages().
175 */
176static int journal_submit_inode_data_buffers(struct address_space *mapping)
177{
178 int ret;
179 struct writeback_control wbc = {
180 .sync_mode = WB_SYNC_ALL,
181 .nr_to_write = mapping->nrpages * 2,
182 .range_start = 0,
183 .range_end = i_size_read(mapping->host),
184 };
185
186 ret = generic_writepages(mapping, &wbc);
187 return ret;
188}
189
190/*
191 * Submit all the data buffers of inode associated with the transaction to
192 * disk.
193 *
194 * We are in a committing transaction. Therefore no new inode can be added to
195 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
196 * operate on from being released while we write out pages.
197 */
198static int journal_submit_data_buffers(journal_t *journal,
199 transaction_t *commit_transaction)
200{
201 struct jbd2_inode *jinode;
202 int err, ret = 0;
203 struct address_space *mapping;
204
205 spin_lock(&journal->j_list_lock);
206 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
207 mapping = jinode->i_vfs_inode->i_mapping;
208 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
209 spin_unlock(&journal->j_list_lock);
210 /*
211 * submit the inode data buffers. We use writepage
212 * instead of writepages. Because writepages can do
213 * block allocation with delalloc. We need to write
214 * only allocated blocks here.
215 */
216 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
217 err = journal_submit_inode_data_buffers(mapping);
218 if (!ret)
219 ret = err;
220 spin_lock(&journal->j_list_lock);
221 J_ASSERT(jinode->i_transaction == commit_transaction);
222 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
223 smp_mb__after_clear_bit();
224 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
225 }
226 spin_unlock(&journal->j_list_lock);
227 return ret;
228}
229
230/*
231 * Wait for data submitted for writeout, refile inodes to proper
232 * transaction if needed.
233 *
234 */
235static int journal_finish_inode_data_buffers(journal_t *journal,
236 transaction_t *commit_transaction)
237{
238 struct jbd2_inode *jinode, *next_i;
239 int err, ret = 0;
240
241 /* For locking, see the comment in journal_submit_data_buffers() */
242 spin_lock(&journal->j_list_lock);
243 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
244 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
245 spin_unlock(&journal->j_list_lock);
246 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
247 if (err) {
248 /*
249 * Because AS_EIO is cleared by
250 * filemap_fdatawait_range(), set it again so
251 * that user process can get -EIO from fsync().
252 */
253 set_bit(AS_EIO,
254 &jinode->i_vfs_inode->i_mapping->flags);
255
256 if (!ret)
257 ret = err;
258 }
259 spin_lock(&journal->j_list_lock);
260 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
261 smp_mb__after_clear_bit();
262 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
263 }
264
265 /* Now refile inode to proper lists */
266 list_for_each_entry_safe(jinode, next_i,
267 &commit_transaction->t_inode_list, i_list) {
268 list_del(&jinode->i_list);
269 if (jinode->i_next_transaction) {
270 jinode->i_transaction = jinode->i_next_transaction;
271 jinode->i_next_transaction = NULL;
272 list_add(&jinode->i_list,
273 &jinode->i_transaction->t_inode_list);
274 } else {
275 jinode->i_transaction = NULL;
276 }
277 }
278 spin_unlock(&journal->j_list_lock);
279
280 return ret;
281}
282
283static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
284{
285 struct page *page = bh->b_page;
286 char *addr;
287 __u32 checksum;
288
289 addr = kmap_atomic(page, KM_USER0);
290 checksum = crc32_be(crc32_sum,
291 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
292 kunmap_atomic(addr, KM_USER0);
293
294 return checksum;
295}
296
297static void write_tag_block(int tag_bytes, journal_block_tag_t *tag,
298 unsigned long long block)
299{
300 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
301 if (tag_bytes > JBD2_TAG_SIZE32)
302 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
303}
304
305/*
306 * jbd2_journal_commit_transaction
307 *
308 * The primary function for committing a transaction to the log. This
309 * function is called by the journal thread to begin a complete commit.
310 */
311void jbd2_journal_commit_transaction(journal_t *journal)
312{
313 struct transaction_stats_s stats;
314 transaction_t *commit_transaction;
315 struct journal_head *jh, *new_jh, *descriptor;
316 struct buffer_head **wbuf = journal->j_wbuf;
317 int bufs;
318 int flags;
319 int err;
320 unsigned long long blocknr;
321 ktime_t start_time;
322 u64 commit_time;
323 char *tagp = NULL;
324 journal_header_t *header;
325 journal_block_tag_t *tag = NULL;
326 int space_left = 0;
327 int first_tag = 0;
328 int tag_flag;
329 int i, to_free = 0;
330 int tag_bytes = journal_tag_bytes(journal);
331 struct buffer_head *cbh = NULL; /* For transactional checksums */
332 __u32 crc32_sum = ~0;
333 struct blk_plug plug;
334
335 /*
336 * First job: lock down the current transaction and wait for
337 * all outstanding updates to complete.
338 */
339
340 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
341 if (journal->j_flags & JBD2_FLUSHED) {
342 jbd_debug(3, "super block updated\n");
343 jbd2_journal_update_superblock(journal, 1);
344 } else {
345 jbd_debug(3, "superblock not updated\n");
346 }
347
348 J_ASSERT(journal->j_running_transaction != NULL);
349 J_ASSERT(journal->j_committing_transaction == NULL);
350
351 commit_transaction = journal->j_running_transaction;
352 J_ASSERT(commit_transaction->t_state == T_RUNNING);
353
354 trace_jbd2_start_commit(journal, commit_transaction);
355 jbd_debug(1, "JBD: starting commit of transaction %d\n",
356 commit_transaction->t_tid);
357
358 write_lock(&journal->j_state_lock);
359 commit_transaction->t_state = T_LOCKED;
360
361 trace_jbd2_commit_locking(journal, commit_transaction);
362 stats.run.rs_wait = commit_transaction->t_max_wait;
363 stats.run.rs_locked = jiffies;
364 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
365 stats.run.rs_locked);
366
367 spin_lock(&commit_transaction->t_handle_lock);
368 while (atomic_read(&commit_transaction->t_updates)) {
369 DEFINE_WAIT(wait);
370
371 prepare_to_wait(&journal->j_wait_updates, &wait,
372 TASK_UNINTERRUPTIBLE);
373 if (atomic_read(&commit_transaction->t_updates)) {
374 spin_unlock(&commit_transaction->t_handle_lock);
375 write_unlock(&journal->j_state_lock);
376 schedule();
377 write_lock(&journal->j_state_lock);
378 spin_lock(&commit_transaction->t_handle_lock);
379 }
380 finish_wait(&journal->j_wait_updates, &wait);
381 }
382 spin_unlock(&commit_transaction->t_handle_lock);
383
384 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
385 journal->j_max_transaction_buffers);
386
387 /*
388 * First thing we are allowed to do is to discard any remaining
389 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
390 * that there are no such buffers: if a large filesystem
391 * operation like a truncate needs to split itself over multiple
392 * transactions, then it may try to do a jbd2_journal_restart() while
393 * there are still BJ_Reserved buffers outstanding. These must
394 * be released cleanly from the current transaction.
395 *
396 * In this case, the filesystem must still reserve write access
397 * again before modifying the buffer in the new transaction, but
398 * we do not require it to remember exactly which old buffers it
399 * has reserved. This is consistent with the existing behaviour
400 * that multiple jbd2_journal_get_write_access() calls to the same
401 * buffer are perfectly permissible.
402 */
403 while (commit_transaction->t_reserved_list) {
404 jh = commit_transaction->t_reserved_list;
405 JBUFFER_TRACE(jh, "reserved, unused: refile");
406 /*
407 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
408 * leave undo-committed data.
409 */
410 if (jh->b_committed_data) {
411 struct buffer_head *bh = jh2bh(jh);
412
413 jbd_lock_bh_state(bh);
414 jbd2_free(jh->b_committed_data, bh->b_size);
415 jh->b_committed_data = NULL;
416 jbd_unlock_bh_state(bh);
417 }
418 jbd2_journal_refile_buffer(journal, jh);
419 }
420
421 /*
422 * Now try to drop any written-back buffers from the journal's
423 * checkpoint lists. We do this *before* commit because it potentially
424 * frees some memory
425 */
426 spin_lock(&journal->j_list_lock);
427 __jbd2_journal_clean_checkpoint_list(journal);
428 spin_unlock(&journal->j_list_lock);
429
430 jbd_debug (3, "JBD: commit phase 1\n");
431
432 /*
433 * Switch to a new revoke table.
434 */
435 jbd2_journal_switch_revoke_table(journal);
436
437 trace_jbd2_commit_flushing(journal, commit_transaction);
438 stats.run.rs_flushing = jiffies;
439 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
440 stats.run.rs_flushing);
441
442 commit_transaction->t_state = T_FLUSH;
443 journal->j_committing_transaction = commit_transaction;
444 journal->j_running_transaction = NULL;
445 start_time = ktime_get();
446 commit_transaction->t_log_start = journal->j_head;
447 wake_up(&journal->j_wait_transaction_locked);
448 write_unlock(&journal->j_state_lock);
449
450 jbd_debug (3, "JBD: commit phase 2\n");
451
452 /*
453 * Now start flushing things to disk, in the order they appear
454 * on the transaction lists. Data blocks go first.
455 */
456 err = journal_submit_data_buffers(journal, commit_transaction);
457 if (err)
458 jbd2_journal_abort(journal, err);
459
460 blk_start_plug(&plug);
461 jbd2_journal_write_revoke_records(journal, commit_transaction,
462 WRITE_SYNC);
463 blk_finish_plug(&plug);
464
465 jbd_debug(3, "JBD: commit phase 2\n");
466
467 /*
468 * Way to go: we have now written out all of the data for a
469 * transaction! Now comes the tricky part: we need to write out
470 * metadata. Loop over the transaction's entire buffer list:
471 */
472 write_lock(&journal->j_state_lock);
473 commit_transaction->t_state = T_COMMIT;
474 write_unlock(&journal->j_state_lock);
475
476 trace_jbd2_commit_logging(journal, commit_transaction);
477 stats.run.rs_logging = jiffies;
478 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
479 stats.run.rs_logging);
480 stats.run.rs_blocks =
481 atomic_read(&commit_transaction->t_outstanding_credits);
482 stats.run.rs_blocks_logged = 0;
483
484 J_ASSERT(commit_transaction->t_nr_buffers <=
485 atomic_read(&commit_transaction->t_outstanding_credits));
486
487 err = 0;
488 descriptor = NULL;
489 bufs = 0;
490 blk_start_plug(&plug);
491 while (commit_transaction->t_buffers) {
492
493 /* Find the next buffer to be journaled... */
494
495 jh = commit_transaction->t_buffers;
496
497 /* If we're in abort mode, we just un-journal the buffer and
498 release it. */
499
500 if (is_journal_aborted(journal)) {
501 clear_buffer_jbddirty(jh2bh(jh));
502 JBUFFER_TRACE(jh, "journal is aborting: refile");
503 jbd2_buffer_abort_trigger(jh,
504 jh->b_frozen_data ?
505 jh->b_frozen_triggers :
506 jh->b_triggers);
507 jbd2_journal_refile_buffer(journal, jh);
508 /* If that was the last one, we need to clean up
509 * any descriptor buffers which may have been
510 * already allocated, even if we are now
511 * aborting. */
512 if (!commit_transaction->t_buffers)
513 goto start_journal_io;
514 continue;
515 }
516
517 /* Make sure we have a descriptor block in which to
518 record the metadata buffer. */
519
520 if (!descriptor) {
521 struct buffer_head *bh;
522
523 J_ASSERT (bufs == 0);
524
525 jbd_debug(4, "JBD: get descriptor\n");
526
527 descriptor = jbd2_journal_get_descriptor_buffer(journal);
528 if (!descriptor) {
529 jbd2_journal_abort(journal, -EIO);
530 continue;
531 }
532
533 bh = jh2bh(descriptor);
534 jbd_debug(4, "JBD: got buffer %llu (%p)\n",
535 (unsigned long long)bh->b_blocknr, bh->b_data);
536 header = (journal_header_t *)&bh->b_data[0];
537 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
538 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK);
539 header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
540
541 tagp = &bh->b_data[sizeof(journal_header_t)];
542 space_left = bh->b_size - sizeof(journal_header_t);
543 first_tag = 1;
544 set_buffer_jwrite(bh);
545 set_buffer_dirty(bh);
546 wbuf[bufs++] = bh;
547
548 /* Record it so that we can wait for IO
549 completion later */
550 BUFFER_TRACE(bh, "ph3: file as descriptor");
551 jbd2_journal_file_buffer(descriptor, commit_transaction,
552 BJ_LogCtl);
553 }
554
555 /* Where is the buffer to be written? */
556
557 err = jbd2_journal_next_log_block(journal, &blocknr);
558 /* If the block mapping failed, just abandon the buffer
559 and repeat this loop: we'll fall into the
560 refile-on-abort condition above. */
561 if (err) {
562 jbd2_journal_abort(journal, err);
563 continue;
564 }
565
566 /*
567 * start_this_handle() uses t_outstanding_credits to determine
568 * the free space in the log, but this counter is changed
569 * by jbd2_journal_next_log_block() also.
570 */
571 atomic_dec(&commit_transaction->t_outstanding_credits);
572
573 /* Bump b_count to prevent truncate from stumbling over
574 the shadowed buffer! @@@ This can go if we ever get
575 rid of the BJ_IO/BJ_Shadow pairing of buffers. */
576 atomic_inc(&jh2bh(jh)->b_count);
577
578 /* Make a temporary IO buffer with which to write it out
579 (this will requeue both the metadata buffer and the
580 temporary IO buffer). new_bh goes on BJ_IO*/
581
582 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
583 /*
584 * akpm: jbd2_journal_write_metadata_buffer() sets
585 * new_bh->b_transaction to commit_transaction.
586 * We need to clean this up before we release new_bh
587 * (which is of type BJ_IO)
588 */
589 JBUFFER_TRACE(jh, "ph3: write metadata");
590 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
591 jh, &new_jh, blocknr);
592 if (flags < 0) {
593 jbd2_journal_abort(journal, flags);
594 continue;
595 }
596 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state);
597 wbuf[bufs++] = jh2bh(new_jh);
598
599 /* Record the new block's tag in the current descriptor
600 buffer */
601
602 tag_flag = 0;
603 if (flags & 1)
604 tag_flag |= JBD2_FLAG_ESCAPE;
605 if (!first_tag)
606 tag_flag |= JBD2_FLAG_SAME_UUID;
607
608 tag = (journal_block_tag_t *) tagp;
609 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr);
610 tag->t_flags = cpu_to_be32(tag_flag);
611 tagp += tag_bytes;
612 space_left -= tag_bytes;
613
614 if (first_tag) {
615 memcpy (tagp, journal->j_uuid, 16);
616 tagp += 16;
617 space_left -= 16;
618 first_tag = 0;
619 }
620
621 /* If there's no more to do, or if the descriptor is full,
622 let the IO rip! */
623
624 if (bufs == journal->j_wbufsize ||
625 commit_transaction->t_buffers == NULL ||
626 space_left < tag_bytes + 16) {
627
628 jbd_debug(4, "JBD: Submit %d IOs\n", bufs);
629
630 /* Write an end-of-descriptor marker before
631 submitting the IOs. "tag" still points to
632 the last tag we set up. */
633
634 tag->t_flags |= cpu_to_be32(JBD2_FLAG_LAST_TAG);
635
636start_journal_io:
637 for (i = 0; i < bufs; i++) {
638 struct buffer_head *bh = wbuf[i];
639 /*
640 * Compute checksum.
641 */
642 if (JBD2_HAS_COMPAT_FEATURE(journal,
643 JBD2_FEATURE_COMPAT_CHECKSUM)) {
644 crc32_sum =
645 jbd2_checksum_data(crc32_sum, bh);
646 }
647
648 lock_buffer(bh);
649 clear_buffer_dirty(bh);
650 set_buffer_uptodate(bh);
651 bh->b_end_io = journal_end_buffer_io_sync;
652 submit_bh(WRITE_SYNC, bh);
653 }
654 cond_resched();
655 stats.run.rs_blocks_logged += bufs;
656
657 /* Force a new descriptor to be generated next
658 time round the loop. */
659 descriptor = NULL;
660 bufs = 0;
661 }
662 }
663
664 err = journal_finish_inode_data_buffers(journal, commit_transaction);
665 if (err) {
666 printk(KERN_WARNING
667 "JBD2: Detected IO errors while flushing file data "
668 "on %s\n", journal->j_devname);
669 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
670 jbd2_journal_abort(journal, err);
671 err = 0;
672 }
673
674 write_lock(&journal->j_state_lock);
675 J_ASSERT(commit_transaction->t_state == T_COMMIT);
676 commit_transaction->t_state = T_COMMIT_DFLUSH;
677 write_unlock(&journal->j_state_lock);
678 /*
679 * If the journal is not located on the file system device,
680 * then we must flush the file system device before we issue
681 * the commit record
682 */
683 if (commit_transaction->t_need_data_flush &&
684 (journal->j_fs_dev != journal->j_dev) &&
685 (journal->j_flags & JBD2_BARRIER))
686 blkdev_issue_flush(journal->j_fs_dev, GFP_KERNEL, NULL);
687
688 /* Done it all: now write the commit record asynchronously. */
689 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
690 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
691 err = journal_submit_commit_record(journal, commit_transaction,
692 &cbh, crc32_sum);
693 if (err)
694 __jbd2_journal_abort_hard(journal);
695 }
696
697 blk_finish_plug(&plug);
698
699 /* Lo and behold: we have just managed to send a transaction to
700 the log. Before we can commit it, wait for the IO so far to
701 complete. Control buffers being written are on the
702 transaction's t_log_list queue, and metadata buffers are on
703 the t_iobuf_list queue.
704
705 Wait for the buffers in reverse order. That way we are
706 less likely to be woken up until all IOs have completed, and
707 so we incur less scheduling load.
708 */
709
710 jbd_debug(3, "JBD: commit phase 3\n");
711
712 /*
713 * akpm: these are BJ_IO, and j_list_lock is not needed.
714 * See __journal_try_to_free_buffer.
715 */
716wait_for_iobuf:
717 while (commit_transaction->t_iobuf_list != NULL) {
718 struct buffer_head *bh;
719
720 jh = commit_transaction->t_iobuf_list->b_tprev;
721 bh = jh2bh(jh);
722 if (buffer_locked(bh)) {
723 wait_on_buffer(bh);
724 goto wait_for_iobuf;
725 }
726 if (cond_resched())
727 goto wait_for_iobuf;
728
729 if (unlikely(!buffer_uptodate(bh)))
730 err = -EIO;
731
732 clear_buffer_jwrite(bh);
733
734 JBUFFER_TRACE(jh, "ph4: unfile after journal write");
735 jbd2_journal_unfile_buffer(journal, jh);
736
737 /*
738 * ->t_iobuf_list should contain only dummy buffer_heads
739 * which were created by jbd2_journal_write_metadata_buffer().
740 */
741 BUFFER_TRACE(bh, "dumping temporary bh");
742 jbd2_journal_put_journal_head(jh);
743 __brelse(bh);
744 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
745 free_buffer_head(bh);
746
747 /* We also have to unlock and free the corresponding
748 shadowed buffer */
749 jh = commit_transaction->t_shadow_list->b_tprev;
750 bh = jh2bh(jh);
751 clear_bit(BH_JWrite, &bh->b_state);
752 J_ASSERT_BH(bh, buffer_jbddirty(bh));
753
754 /* The metadata is now released for reuse, but we need
755 to remember it against this transaction so that when
756 we finally commit, we can do any checkpointing
757 required. */
758 JBUFFER_TRACE(jh, "file as BJ_Forget");
759 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
760 /*
761 * Wake up any transactions which were waiting for this IO to
762 * complete. The barrier must be here so that changes by
763 * jbd2_journal_file_buffer() take effect before wake_up_bit()
764 * does the waitqueue check.
765 */
766 smp_mb();
767 wake_up_bit(&bh->b_state, BH_Unshadow);
768 JBUFFER_TRACE(jh, "brelse shadowed buffer");
769 __brelse(bh);
770 }
771
772 J_ASSERT (commit_transaction->t_shadow_list == NULL);
773
774 jbd_debug(3, "JBD: commit phase 4\n");
775
776 /* Here we wait for the revoke record and descriptor record buffers */
777 wait_for_ctlbuf:
778 while (commit_transaction->t_log_list != NULL) {
779 struct buffer_head *bh;
780
781 jh = commit_transaction->t_log_list->b_tprev;
782 bh = jh2bh(jh);
783 if (buffer_locked(bh)) {
784 wait_on_buffer(bh);
785 goto wait_for_ctlbuf;
786 }
787 if (cond_resched())
788 goto wait_for_ctlbuf;
789
790 if (unlikely(!buffer_uptodate(bh)))
791 err = -EIO;
792
793 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
794 clear_buffer_jwrite(bh);
795 jbd2_journal_unfile_buffer(journal, jh);
796 jbd2_journal_put_journal_head(jh);
797 __brelse(bh); /* One for getblk */
798 /* AKPM: bforget here */
799 }
800
801 if (err)
802 jbd2_journal_abort(journal, err);
803
804 jbd_debug(3, "JBD: commit phase 5\n");
805 write_lock(&journal->j_state_lock);
806 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
807 commit_transaction->t_state = T_COMMIT_JFLUSH;
808 write_unlock(&journal->j_state_lock);
809
810 if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
811 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
812 err = journal_submit_commit_record(journal, commit_transaction,
813 &cbh, crc32_sum);
814 if (err)
815 __jbd2_journal_abort_hard(journal);
816 }
817 if (cbh)
818 err = journal_wait_on_commit_record(journal, cbh);
819 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
820 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) &&
821 journal->j_flags & JBD2_BARRIER) {
822 blkdev_issue_flush(journal->j_dev, GFP_KERNEL, NULL);
823 }
824
825 if (err)
826 jbd2_journal_abort(journal, err);
827
828 /* End of a transaction! Finally, we can do checkpoint
829 processing: any buffers committed as a result of this
830 transaction can be removed from any checkpoint list it was on
831 before. */
832
833 jbd_debug(3, "JBD: commit phase 6\n");
834
835 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
836 J_ASSERT(commit_transaction->t_buffers == NULL);
837 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
838 J_ASSERT(commit_transaction->t_iobuf_list == NULL);
839 J_ASSERT(commit_transaction->t_shadow_list == NULL);
840 J_ASSERT(commit_transaction->t_log_list == NULL);
841
842restart_loop:
843 /*
844 * As there are other places (journal_unmap_buffer()) adding buffers
845 * to this list we have to be careful and hold the j_list_lock.
846 */
847 spin_lock(&journal->j_list_lock);
848 while (commit_transaction->t_forget) {
849 transaction_t *cp_transaction;
850 struct buffer_head *bh;
851 int try_to_free = 0;
852
853 jh = commit_transaction->t_forget;
854 spin_unlock(&journal->j_list_lock);
855 bh = jh2bh(jh);
856 /*
857 * Get a reference so that bh cannot be freed before we are
858 * done with it.
859 */
860 get_bh(bh);
861 jbd_lock_bh_state(bh);
862 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
863
864 /*
865 * If there is undo-protected committed data against
866 * this buffer, then we can remove it now. If it is a
867 * buffer needing such protection, the old frozen_data
868 * field now points to a committed version of the
869 * buffer, so rotate that field to the new committed
870 * data.
871 *
872 * Otherwise, we can just throw away the frozen data now.
873 *
874 * We also know that the frozen data has already fired
875 * its triggers if they exist, so we can clear that too.
876 */
877 if (jh->b_committed_data) {
878 jbd2_free(jh->b_committed_data, bh->b_size);
879 jh->b_committed_data = NULL;
880 if (jh->b_frozen_data) {
881 jh->b_committed_data = jh->b_frozen_data;
882 jh->b_frozen_data = NULL;
883 jh->b_frozen_triggers = NULL;
884 }
885 } else if (jh->b_frozen_data) {
886 jbd2_free(jh->b_frozen_data, bh->b_size);
887 jh->b_frozen_data = NULL;
888 jh->b_frozen_triggers = NULL;
889 }
890
891 spin_lock(&journal->j_list_lock);
892 cp_transaction = jh->b_cp_transaction;
893 if (cp_transaction) {
894 JBUFFER_TRACE(jh, "remove from old cp transaction");
895 cp_transaction->t_chp_stats.cs_dropped++;
896 __jbd2_journal_remove_checkpoint(jh);
897 }
898
899 /* Only re-checkpoint the buffer_head if it is marked
900 * dirty. If the buffer was added to the BJ_Forget list
901 * by jbd2_journal_forget, it may no longer be dirty and
902 * there's no point in keeping a checkpoint record for
903 * it. */
904
905 /* A buffer which has been freed while still being
906 * journaled by a previous transaction may end up still
907 * being dirty here, but we want to avoid writing back
908 * that buffer in the future after the "add to orphan"
909 * operation been committed, That's not only a performance
910 * gain, it also stops aliasing problems if the buffer is
911 * left behind for writeback and gets reallocated for another
912 * use in a different page. */
913 if (buffer_freed(bh) && !jh->b_next_transaction) {
914 clear_buffer_freed(bh);
915 clear_buffer_jbddirty(bh);
916 }
917
918 if (buffer_jbddirty(bh)) {
919 JBUFFER_TRACE(jh, "add to new checkpointing trans");
920 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
921 if (is_journal_aborted(journal))
922 clear_buffer_jbddirty(bh);
923 } else {
924 J_ASSERT_BH(bh, !buffer_dirty(bh));
925 /*
926 * The buffer on BJ_Forget list and not jbddirty means
927 * it has been freed by this transaction and hence it
928 * could not have been reallocated until this
929 * transaction has committed. *BUT* it could be
930 * reallocated once we have written all the data to
931 * disk and before we process the buffer on BJ_Forget
932 * list.
933 */
934 if (!jh->b_next_transaction)
935 try_to_free = 1;
936 }
937 JBUFFER_TRACE(jh, "refile or unfile buffer");
938 __jbd2_journal_refile_buffer(jh);
939 jbd_unlock_bh_state(bh);
940 if (try_to_free)
941 release_buffer_page(bh); /* Drops bh reference */
942 else
943 __brelse(bh);
944 cond_resched_lock(&journal->j_list_lock);
945 }
946 spin_unlock(&journal->j_list_lock);
947 /*
948 * This is a bit sleazy. We use j_list_lock to protect transition
949 * of a transaction into T_FINISHED state and calling
950 * __jbd2_journal_drop_transaction(). Otherwise we could race with
951 * other checkpointing code processing the transaction...
952 */
953 write_lock(&journal->j_state_lock);
954 spin_lock(&journal->j_list_lock);
955 /*
956 * Now recheck if some buffers did not get attached to the transaction
957 * while the lock was dropped...
958 */
959 if (commit_transaction->t_forget) {
960 spin_unlock(&journal->j_list_lock);
961 write_unlock(&journal->j_state_lock);
962 goto restart_loop;
963 }
964
965 /* Done with this transaction! */
966
967 jbd_debug(3, "JBD: commit phase 7\n");
968
969 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
970
971 commit_transaction->t_start = jiffies;
972 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
973 commit_transaction->t_start);
974
975 /*
976 * File the transaction statistics
977 */
978 stats.ts_tid = commit_transaction->t_tid;
979 stats.run.rs_handle_count =
980 atomic_read(&commit_transaction->t_handle_count);
981 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
982 commit_transaction->t_tid, &stats.run);
983
984 /*
985 * Calculate overall stats
986 */
987 spin_lock(&journal->j_history_lock);
988 journal->j_stats.ts_tid++;
989 journal->j_stats.run.rs_wait += stats.run.rs_wait;
990 journal->j_stats.run.rs_running += stats.run.rs_running;
991 journal->j_stats.run.rs_locked += stats.run.rs_locked;
992 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
993 journal->j_stats.run.rs_logging += stats.run.rs_logging;
994 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
995 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
996 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
997 spin_unlock(&journal->j_history_lock);
998
999 commit_transaction->t_state = T_FINISHED;
1000 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1001 journal->j_commit_sequence = commit_transaction->t_tid;
1002 journal->j_committing_transaction = NULL;
1003 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1004
1005 /*
1006 * weight the commit time higher than the average time so we don't
1007 * react too strongly to vast changes in the commit time
1008 */
1009 if (likely(journal->j_average_commit_time))
1010 journal->j_average_commit_time = (commit_time +
1011 journal->j_average_commit_time*3) / 4;
1012 else
1013 journal->j_average_commit_time = commit_time;
1014 write_unlock(&journal->j_state_lock);
1015
1016 if (commit_transaction->t_checkpoint_list == NULL &&
1017 commit_transaction->t_checkpoint_io_list == NULL) {
1018 __jbd2_journal_drop_transaction(journal, commit_transaction);
1019 to_free = 1;
1020 } else {
1021 if (journal->j_checkpoint_transactions == NULL) {
1022 journal->j_checkpoint_transactions = commit_transaction;
1023 commit_transaction->t_cpnext = commit_transaction;
1024 commit_transaction->t_cpprev = commit_transaction;
1025 } else {
1026 commit_transaction->t_cpnext =
1027 journal->j_checkpoint_transactions;
1028 commit_transaction->t_cpprev =
1029 commit_transaction->t_cpnext->t_cpprev;
1030 commit_transaction->t_cpnext->t_cpprev =
1031 commit_transaction;
1032 commit_transaction->t_cpprev->t_cpnext =
1033 commit_transaction;
1034 }
1035 }
1036 spin_unlock(&journal->j_list_lock);
1037
1038 if (journal->j_commit_callback)
1039 journal->j_commit_callback(journal, commit_transaction);
1040
1041 trace_jbd2_end_commit(journal, commit_transaction);
1042 jbd_debug(1, "JBD: commit %d complete, head %d\n",
1043 journal->j_commit_sequence, journal->j_tail_sequence);
1044 if (to_free)
1045 kfree(commit_transaction);
1046
1047 wake_up(&journal->j_wait_done_commit);
1048}
1/*
2 * linux/fs/jbd2/commit.c
3 *
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
5 *
6 * Copyright 1998 Red Hat corp --- All Rights Reserved
7 *
8 * This file is part of the Linux kernel and is made available under
9 * the terms of the GNU General Public License, version 2, or at your
10 * option, any later version, incorporated herein by reference.
11 *
12 * Journal commit routines for the generic filesystem journaling code;
13 * part of the ext2fs journaling system.
14 */
15
16#include <linux/time.h>
17#include <linux/fs.h>
18#include <linux/jbd2.h>
19#include <linux/errno.h>
20#include <linux/slab.h>
21#include <linux/mm.h>
22#include <linux/pagemap.h>
23#include <linux/jiffies.h>
24#include <linux/crc32.h>
25#include <linux/writeback.h>
26#include <linux/backing-dev.h>
27#include <linux/bio.h>
28#include <linux/blkdev.h>
29#include <linux/bitops.h>
30#include <trace/events/jbd2.h>
31
32/*
33 * IO end handler for temporary buffer_heads handling writes to the journal.
34 */
35static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
36{
37 struct buffer_head *orig_bh = bh->b_private;
38
39 BUFFER_TRACE(bh, "");
40 if (uptodate)
41 set_buffer_uptodate(bh);
42 else
43 clear_buffer_uptodate(bh);
44 if (orig_bh) {
45 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
46 smp_mb__after_atomic();
47 wake_up_bit(&orig_bh->b_state, BH_Shadow);
48 }
49 unlock_buffer(bh);
50}
51
52/*
53 * When an ext4 file is truncated, it is possible that some pages are not
54 * successfully freed, because they are attached to a committing transaction.
55 * After the transaction commits, these pages are left on the LRU, with no
56 * ->mapping, and with attached buffers. These pages are trivially reclaimable
57 * by the VM, but their apparent absence upsets the VM accounting, and it makes
58 * the numbers in /proc/meminfo look odd.
59 *
60 * So here, we have a buffer which has just come off the forget list. Look to
61 * see if we can strip all buffers from the backing page.
62 *
63 * Called under lock_journal(), and possibly under journal_datalist_lock. The
64 * caller provided us with a ref against the buffer, and we drop that here.
65 */
66static void release_buffer_page(struct buffer_head *bh)
67{
68 struct page *page;
69
70 if (buffer_dirty(bh))
71 goto nope;
72 if (atomic_read(&bh->b_count) != 1)
73 goto nope;
74 page = bh->b_page;
75 if (!page)
76 goto nope;
77 if (page->mapping)
78 goto nope;
79
80 /* OK, it's a truncated page */
81 if (!trylock_page(page))
82 goto nope;
83
84 get_page(page);
85 __brelse(bh);
86 try_to_free_buffers(page);
87 unlock_page(page);
88 put_page(page);
89 return;
90
91nope:
92 __brelse(bh);
93}
94
95static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
96{
97 struct commit_header *h;
98 __u32 csum;
99
100 if (!jbd2_journal_has_csum_v2or3(j))
101 return;
102
103 h = (struct commit_header *)(bh->b_data);
104 h->h_chksum_type = 0;
105 h->h_chksum_size = 0;
106 h->h_chksum[0] = 0;
107 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
108 h->h_chksum[0] = cpu_to_be32(csum);
109}
110
111/*
112 * Done it all: now submit the commit record. We should have
113 * cleaned up our previous buffers by now, so if we are in abort
114 * mode we can now just skip the rest of the journal write
115 * entirely.
116 *
117 * Returns 1 if the journal needs to be aborted or 0 on success
118 */
119static int journal_submit_commit_record(journal_t *journal,
120 transaction_t *commit_transaction,
121 struct buffer_head **cbh,
122 __u32 crc32_sum)
123{
124 struct commit_header *tmp;
125 struct buffer_head *bh;
126 int ret;
127 struct timespec64 now = current_kernel_time64();
128
129 *cbh = NULL;
130
131 if (is_journal_aborted(journal))
132 return 0;
133
134 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
135 JBD2_COMMIT_BLOCK);
136 if (!bh)
137 return 1;
138
139 tmp = (struct commit_header *)bh->b_data;
140 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
141 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
142
143 if (jbd2_has_feature_checksum(journal)) {
144 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
145 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
146 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
147 }
148 jbd2_commit_block_csum_set(journal, bh);
149
150 BUFFER_TRACE(bh, "submit commit block");
151 lock_buffer(bh);
152 clear_buffer_dirty(bh);
153 set_buffer_uptodate(bh);
154 bh->b_end_io = journal_end_buffer_io_sync;
155
156 if (journal->j_flags & JBD2_BARRIER &&
157 !jbd2_has_feature_async_commit(journal))
158 ret = submit_bh(REQ_OP_WRITE,
159 REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh);
160 else
161 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
162
163 *cbh = bh;
164 return ret;
165}
166
167/*
168 * This function along with journal_submit_commit_record
169 * allows to write the commit record asynchronously.
170 */
171static int journal_wait_on_commit_record(journal_t *journal,
172 struct buffer_head *bh)
173{
174 int ret = 0;
175
176 clear_buffer_dirty(bh);
177 wait_on_buffer(bh);
178
179 if (unlikely(!buffer_uptodate(bh)))
180 ret = -EIO;
181 put_bh(bh); /* One for getblk() */
182
183 return ret;
184}
185
186/*
187 * write the filemap data using writepage() address_space_operations.
188 * We don't do block allocation here even for delalloc. We don't
189 * use writepages() because with dealyed allocation we may be doing
190 * block allocation in writepages().
191 */
192static int journal_submit_inode_data_buffers(struct address_space *mapping)
193{
194 int ret;
195 struct writeback_control wbc = {
196 .sync_mode = WB_SYNC_ALL,
197 .nr_to_write = mapping->nrpages * 2,
198 .range_start = 0,
199 .range_end = i_size_read(mapping->host),
200 };
201
202 ret = generic_writepages(mapping, &wbc);
203 return ret;
204}
205
206/*
207 * Submit all the data buffers of inode associated with the transaction to
208 * disk.
209 *
210 * We are in a committing transaction. Therefore no new inode can be added to
211 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
212 * operate on from being released while we write out pages.
213 */
214static int journal_submit_data_buffers(journal_t *journal,
215 transaction_t *commit_transaction)
216{
217 struct jbd2_inode *jinode;
218 int err, ret = 0;
219 struct address_space *mapping;
220
221 spin_lock(&journal->j_list_lock);
222 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
223 if (!(jinode->i_flags & JI_WRITE_DATA))
224 continue;
225 mapping = jinode->i_vfs_inode->i_mapping;
226 jinode->i_flags |= JI_COMMIT_RUNNING;
227 spin_unlock(&journal->j_list_lock);
228 /*
229 * submit the inode data buffers. We use writepage
230 * instead of writepages. Because writepages can do
231 * block allocation with delalloc. We need to write
232 * only allocated blocks here.
233 */
234 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
235 err = journal_submit_inode_data_buffers(mapping);
236 if (!ret)
237 ret = err;
238 spin_lock(&journal->j_list_lock);
239 J_ASSERT(jinode->i_transaction == commit_transaction);
240 jinode->i_flags &= ~JI_COMMIT_RUNNING;
241 smp_mb();
242 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
243 }
244 spin_unlock(&journal->j_list_lock);
245 return ret;
246}
247
248/*
249 * Wait for data submitted for writeout, refile inodes to proper
250 * transaction if needed.
251 *
252 */
253static int journal_finish_inode_data_buffers(journal_t *journal,
254 transaction_t *commit_transaction)
255{
256 struct jbd2_inode *jinode, *next_i;
257 int err, ret = 0;
258
259 /* For locking, see the comment in journal_submit_data_buffers() */
260 spin_lock(&journal->j_list_lock);
261 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
262 if (!(jinode->i_flags & JI_WAIT_DATA))
263 continue;
264 jinode->i_flags |= JI_COMMIT_RUNNING;
265 spin_unlock(&journal->j_list_lock);
266 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
267 if (err) {
268 /*
269 * Because AS_EIO is cleared by
270 * filemap_fdatawait_range(), set it again so
271 * that user process can get -EIO from fsync().
272 */
273 mapping_set_error(jinode->i_vfs_inode->i_mapping, -EIO);
274
275 if (!ret)
276 ret = err;
277 }
278 spin_lock(&journal->j_list_lock);
279 jinode->i_flags &= ~JI_COMMIT_RUNNING;
280 smp_mb();
281 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
282 }
283
284 /* Now refile inode to proper lists */
285 list_for_each_entry_safe(jinode, next_i,
286 &commit_transaction->t_inode_list, i_list) {
287 list_del(&jinode->i_list);
288 if (jinode->i_next_transaction) {
289 jinode->i_transaction = jinode->i_next_transaction;
290 jinode->i_next_transaction = NULL;
291 list_add(&jinode->i_list,
292 &jinode->i_transaction->t_inode_list);
293 } else {
294 jinode->i_transaction = NULL;
295 }
296 }
297 spin_unlock(&journal->j_list_lock);
298
299 return ret;
300}
301
302static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
303{
304 struct page *page = bh->b_page;
305 char *addr;
306 __u32 checksum;
307
308 addr = kmap_atomic(page);
309 checksum = crc32_be(crc32_sum,
310 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
311 kunmap_atomic(addr);
312
313 return checksum;
314}
315
316static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
317 unsigned long long block)
318{
319 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
320 if (jbd2_has_feature_64bit(j))
321 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
322}
323
324static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
325 struct buffer_head *bh, __u32 sequence)
326{
327 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
328 struct page *page = bh->b_page;
329 __u8 *addr;
330 __u32 csum32;
331 __be32 seq;
332
333 if (!jbd2_journal_has_csum_v2or3(j))
334 return;
335
336 seq = cpu_to_be32(sequence);
337 addr = kmap_atomic(page);
338 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
339 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
340 bh->b_size);
341 kunmap_atomic(addr);
342
343 if (jbd2_has_feature_csum3(j))
344 tag3->t_checksum = cpu_to_be32(csum32);
345 else
346 tag->t_checksum = cpu_to_be16(csum32);
347}
348/*
349 * jbd2_journal_commit_transaction
350 *
351 * The primary function for committing a transaction to the log. This
352 * function is called by the journal thread to begin a complete commit.
353 */
354void jbd2_journal_commit_transaction(journal_t *journal)
355{
356 struct transaction_stats_s stats;
357 transaction_t *commit_transaction;
358 struct journal_head *jh;
359 struct buffer_head *descriptor;
360 struct buffer_head **wbuf = journal->j_wbuf;
361 int bufs;
362 int flags;
363 int err;
364 unsigned long long blocknr;
365 ktime_t start_time;
366 u64 commit_time;
367 char *tagp = NULL;
368 journal_block_tag_t *tag = NULL;
369 int space_left = 0;
370 int first_tag = 0;
371 int tag_flag;
372 int i;
373 int tag_bytes = journal_tag_bytes(journal);
374 struct buffer_head *cbh = NULL; /* For transactional checksums */
375 __u32 crc32_sum = ~0;
376 struct blk_plug plug;
377 /* Tail of the journal */
378 unsigned long first_block;
379 tid_t first_tid;
380 int update_tail;
381 int csum_size = 0;
382 LIST_HEAD(io_bufs);
383 LIST_HEAD(log_bufs);
384
385 if (jbd2_journal_has_csum_v2or3(journal))
386 csum_size = sizeof(struct jbd2_journal_block_tail);
387
388 /*
389 * First job: lock down the current transaction and wait for
390 * all outstanding updates to complete.
391 */
392
393 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
394 if (journal->j_flags & JBD2_FLUSHED) {
395 jbd_debug(3, "super block updated\n");
396 mutex_lock(&journal->j_checkpoint_mutex);
397 /*
398 * We hold j_checkpoint_mutex so tail cannot change under us.
399 * We don't need any special data guarantees for writing sb
400 * since journal is empty and it is ok for write to be
401 * flushed only with transaction commit.
402 */
403 jbd2_journal_update_sb_log_tail(journal,
404 journal->j_tail_sequence,
405 journal->j_tail,
406 REQ_SYNC);
407 mutex_unlock(&journal->j_checkpoint_mutex);
408 } else {
409 jbd_debug(3, "superblock not updated\n");
410 }
411
412 J_ASSERT(journal->j_running_transaction != NULL);
413 J_ASSERT(journal->j_committing_transaction == NULL);
414
415 commit_transaction = journal->j_running_transaction;
416
417 trace_jbd2_start_commit(journal, commit_transaction);
418 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
419 commit_transaction->t_tid);
420
421 write_lock(&journal->j_state_lock);
422 J_ASSERT(commit_transaction->t_state == T_RUNNING);
423 commit_transaction->t_state = T_LOCKED;
424
425 trace_jbd2_commit_locking(journal, commit_transaction);
426 stats.run.rs_wait = commit_transaction->t_max_wait;
427 stats.run.rs_request_delay = 0;
428 stats.run.rs_locked = jiffies;
429 if (commit_transaction->t_requested)
430 stats.run.rs_request_delay =
431 jbd2_time_diff(commit_transaction->t_requested,
432 stats.run.rs_locked);
433 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
434 stats.run.rs_locked);
435
436 spin_lock(&commit_transaction->t_handle_lock);
437 while (atomic_read(&commit_transaction->t_updates)) {
438 DEFINE_WAIT(wait);
439
440 prepare_to_wait(&journal->j_wait_updates, &wait,
441 TASK_UNINTERRUPTIBLE);
442 if (atomic_read(&commit_transaction->t_updates)) {
443 spin_unlock(&commit_transaction->t_handle_lock);
444 write_unlock(&journal->j_state_lock);
445 schedule();
446 write_lock(&journal->j_state_lock);
447 spin_lock(&commit_transaction->t_handle_lock);
448 }
449 finish_wait(&journal->j_wait_updates, &wait);
450 }
451 spin_unlock(&commit_transaction->t_handle_lock);
452
453 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
454 journal->j_max_transaction_buffers);
455
456 /*
457 * First thing we are allowed to do is to discard any remaining
458 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
459 * that there are no such buffers: if a large filesystem
460 * operation like a truncate needs to split itself over multiple
461 * transactions, then it may try to do a jbd2_journal_restart() while
462 * there are still BJ_Reserved buffers outstanding. These must
463 * be released cleanly from the current transaction.
464 *
465 * In this case, the filesystem must still reserve write access
466 * again before modifying the buffer in the new transaction, but
467 * we do not require it to remember exactly which old buffers it
468 * has reserved. This is consistent with the existing behaviour
469 * that multiple jbd2_journal_get_write_access() calls to the same
470 * buffer are perfectly permissible.
471 */
472 while (commit_transaction->t_reserved_list) {
473 jh = commit_transaction->t_reserved_list;
474 JBUFFER_TRACE(jh, "reserved, unused: refile");
475 /*
476 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
477 * leave undo-committed data.
478 */
479 if (jh->b_committed_data) {
480 struct buffer_head *bh = jh2bh(jh);
481
482 jbd_lock_bh_state(bh);
483 jbd2_free(jh->b_committed_data, bh->b_size);
484 jh->b_committed_data = NULL;
485 jbd_unlock_bh_state(bh);
486 }
487 jbd2_journal_refile_buffer(journal, jh);
488 }
489
490 /*
491 * Now try to drop any written-back buffers from the journal's
492 * checkpoint lists. We do this *before* commit because it potentially
493 * frees some memory
494 */
495 spin_lock(&journal->j_list_lock);
496 __jbd2_journal_clean_checkpoint_list(journal, false);
497 spin_unlock(&journal->j_list_lock);
498
499 jbd_debug(3, "JBD2: commit phase 1\n");
500
501 /*
502 * Clear revoked flag to reflect there is no revoked buffers
503 * in the next transaction which is going to be started.
504 */
505 jbd2_clear_buffer_revoked_flags(journal);
506
507 /*
508 * Switch to a new revoke table.
509 */
510 jbd2_journal_switch_revoke_table(journal);
511
512 /*
513 * Reserved credits cannot be claimed anymore, free them
514 */
515 atomic_sub(atomic_read(&journal->j_reserved_credits),
516 &commit_transaction->t_outstanding_credits);
517
518 trace_jbd2_commit_flushing(journal, commit_transaction);
519 stats.run.rs_flushing = jiffies;
520 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
521 stats.run.rs_flushing);
522
523 commit_transaction->t_state = T_FLUSH;
524 journal->j_committing_transaction = commit_transaction;
525 journal->j_running_transaction = NULL;
526 start_time = ktime_get();
527 commit_transaction->t_log_start = journal->j_head;
528 wake_up(&journal->j_wait_transaction_locked);
529 write_unlock(&journal->j_state_lock);
530
531 jbd_debug(3, "JBD2: commit phase 2a\n");
532
533 /*
534 * Now start flushing things to disk, in the order they appear
535 * on the transaction lists. Data blocks go first.
536 */
537 err = journal_submit_data_buffers(journal, commit_transaction);
538 if (err)
539 jbd2_journal_abort(journal, err);
540
541 blk_start_plug(&plug);
542 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
543
544 jbd_debug(3, "JBD2: commit phase 2b\n");
545
546 /*
547 * Way to go: we have now written out all of the data for a
548 * transaction! Now comes the tricky part: we need to write out
549 * metadata. Loop over the transaction's entire buffer list:
550 */
551 write_lock(&journal->j_state_lock);
552 commit_transaction->t_state = T_COMMIT;
553 write_unlock(&journal->j_state_lock);
554
555 trace_jbd2_commit_logging(journal, commit_transaction);
556 stats.run.rs_logging = jiffies;
557 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
558 stats.run.rs_logging);
559 stats.run.rs_blocks =
560 atomic_read(&commit_transaction->t_outstanding_credits);
561 stats.run.rs_blocks_logged = 0;
562
563 J_ASSERT(commit_transaction->t_nr_buffers <=
564 atomic_read(&commit_transaction->t_outstanding_credits));
565
566 err = 0;
567 bufs = 0;
568 descriptor = NULL;
569 while (commit_transaction->t_buffers) {
570
571 /* Find the next buffer to be journaled... */
572
573 jh = commit_transaction->t_buffers;
574
575 /* If we're in abort mode, we just un-journal the buffer and
576 release it. */
577
578 if (is_journal_aborted(journal)) {
579 clear_buffer_jbddirty(jh2bh(jh));
580 JBUFFER_TRACE(jh, "journal is aborting: refile");
581 jbd2_buffer_abort_trigger(jh,
582 jh->b_frozen_data ?
583 jh->b_frozen_triggers :
584 jh->b_triggers);
585 jbd2_journal_refile_buffer(journal, jh);
586 /* If that was the last one, we need to clean up
587 * any descriptor buffers which may have been
588 * already allocated, even if we are now
589 * aborting. */
590 if (!commit_transaction->t_buffers)
591 goto start_journal_io;
592 continue;
593 }
594
595 /* Make sure we have a descriptor block in which to
596 record the metadata buffer. */
597
598 if (!descriptor) {
599 J_ASSERT (bufs == 0);
600
601 jbd_debug(4, "JBD2: get descriptor\n");
602
603 descriptor = jbd2_journal_get_descriptor_buffer(
604 commit_transaction,
605 JBD2_DESCRIPTOR_BLOCK);
606 if (!descriptor) {
607 jbd2_journal_abort(journal, -EIO);
608 continue;
609 }
610
611 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
612 (unsigned long long)descriptor->b_blocknr,
613 descriptor->b_data);
614 tagp = &descriptor->b_data[sizeof(journal_header_t)];
615 space_left = descriptor->b_size -
616 sizeof(journal_header_t);
617 first_tag = 1;
618 set_buffer_jwrite(descriptor);
619 set_buffer_dirty(descriptor);
620 wbuf[bufs++] = descriptor;
621
622 /* Record it so that we can wait for IO
623 completion later */
624 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
625 jbd2_file_log_bh(&log_bufs, descriptor);
626 }
627
628 /* Where is the buffer to be written? */
629
630 err = jbd2_journal_next_log_block(journal, &blocknr);
631 /* If the block mapping failed, just abandon the buffer
632 and repeat this loop: we'll fall into the
633 refile-on-abort condition above. */
634 if (err) {
635 jbd2_journal_abort(journal, err);
636 continue;
637 }
638
639 /*
640 * start_this_handle() uses t_outstanding_credits to determine
641 * the free space in the log, but this counter is changed
642 * by jbd2_journal_next_log_block() also.
643 */
644 atomic_dec(&commit_transaction->t_outstanding_credits);
645
646 /* Bump b_count to prevent truncate from stumbling over
647 the shadowed buffer! @@@ This can go if we ever get
648 rid of the shadow pairing of buffers. */
649 atomic_inc(&jh2bh(jh)->b_count);
650
651 /*
652 * Make a temporary IO buffer with which to write it out
653 * (this will requeue the metadata buffer to BJ_Shadow).
654 */
655 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
656 JBUFFER_TRACE(jh, "ph3: write metadata");
657 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
658 jh, &wbuf[bufs], blocknr);
659 if (flags < 0) {
660 jbd2_journal_abort(journal, flags);
661 continue;
662 }
663 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
664
665 /* Record the new block's tag in the current descriptor
666 buffer */
667
668 tag_flag = 0;
669 if (flags & 1)
670 tag_flag |= JBD2_FLAG_ESCAPE;
671 if (!first_tag)
672 tag_flag |= JBD2_FLAG_SAME_UUID;
673
674 tag = (journal_block_tag_t *) tagp;
675 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
676 tag->t_flags = cpu_to_be16(tag_flag);
677 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
678 commit_transaction->t_tid);
679 tagp += tag_bytes;
680 space_left -= tag_bytes;
681 bufs++;
682
683 if (first_tag) {
684 memcpy (tagp, journal->j_uuid, 16);
685 tagp += 16;
686 space_left -= 16;
687 first_tag = 0;
688 }
689
690 /* If there's no more to do, or if the descriptor is full,
691 let the IO rip! */
692
693 if (bufs == journal->j_wbufsize ||
694 commit_transaction->t_buffers == NULL ||
695 space_left < tag_bytes + 16 + csum_size) {
696
697 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
698
699 /* Write an end-of-descriptor marker before
700 submitting the IOs. "tag" still points to
701 the last tag we set up. */
702
703 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
704
705 jbd2_descriptor_block_csum_set(journal, descriptor);
706start_journal_io:
707 for (i = 0; i < bufs; i++) {
708 struct buffer_head *bh = wbuf[i];
709 /*
710 * Compute checksum.
711 */
712 if (jbd2_has_feature_checksum(journal)) {
713 crc32_sum =
714 jbd2_checksum_data(crc32_sum, bh);
715 }
716
717 lock_buffer(bh);
718 clear_buffer_dirty(bh);
719 set_buffer_uptodate(bh);
720 bh->b_end_io = journal_end_buffer_io_sync;
721 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
722 }
723 cond_resched();
724 stats.run.rs_blocks_logged += bufs;
725
726 /* Force a new descriptor to be generated next
727 time round the loop. */
728 descriptor = NULL;
729 bufs = 0;
730 }
731 }
732
733 err = journal_finish_inode_data_buffers(journal, commit_transaction);
734 if (err) {
735 printk(KERN_WARNING
736 "JBD2: Detected IO errors while flushing file data "
737 "on %s\n", journal->j_devname);
738 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
739 jbd2_journal_abort(journal, err);
740 err = 0;
741 }
742
743 /*
744 * Get current oldest transaction in the log before we issue flush
745 * to the filesystem device. After the flush we can be sure that
746 * blocks of all older transactions are checkpointed to persistent
747 * storage and we will be safe to update journal start in the
748 * superblock with the numbers we get here.
749 */
750 update_tail =
751 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
752
753 write_lock(&journal->j_state_lock);
754 if (update_tail) {
755 long freed = first_block - journal->j_tail;
756
757 if (first_block < journal->j_tail)
758 freed += journal->j_last - journal->j_first;
759 /* Update tail only if we free significant amount of space */
760 if (freed < journal->j_maxlen / 4)
761 update_tail = 0;
762 }
763 J_ASSERT(commit_transaction->t_state == T_COMMIT);
764 commit_transaction->t_state = T_COMMIT_DFLUSH;
765 write_unlock(&journal->j_state_lock);
766
767 /*
768 * If the journal is not located on the file system device,
769 * then we must flush the file system device before we issue
770 * the commit record
771 */
772 if (commit_transaction->t_need_data_flush &&
773 (journal->j_fs_dev != journal->j_dev) &&
774 (journal->j_flags & JBD2_BARRIER))
775 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
776
777 /* Done it all: now write the commit record asynchronously. */
778 if (jbd2_has_feature_async_commit(journal)) {
779 err = journal_submit_commit_record(journal, commit_transaction,
780 &cbh, crc32_sum);
781 if (err)
782 __jbd2_journal_abort_hard(journal);
783 }
784
785 blk_finish_plug(&plug);
786
787 /* Lo and behold: we have just managed to send a transaction to
788 the log. Before we can commit it, wait for the IO so far to
789 complete. Control buffers being written are on the
790 transaction's t_log_list queue, and metadata buffers are on
791 the io_bufs list.
792
793 Wait for the buffers in reverse order. That way we are
794 less likely to be woken up until all IOs have completed, and
795 so we incur less scheduling load.
796 */
797
798 jbd_debug(3, "JBD2: commit phase 3\n");
799
800 while (!list_empty(&io_bufs)) {
801 struct buffer_head *bh = list_entry(io_bufs.prev,
802 struct buffer_head,
803 b_assoc_buffers);
804
805 wait_on_buffer(bh);
806 cond_resched();
807
808 if (unlikely(!buffer_uptodate(bh)))
809 err = -EIO;
810 jbd2_unfile_log_bh(bh);
811
812 /*
813 * The list contains temporary buffer heads created by
814 * jbd2_journal_write_metadata_buffer().
815 */
816 BUFFER_TRACE(bh, "dumping temporary bh");
817 __brelse(bh);
818 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
819 free_buffer_head(bh);
820
821 /* We also have to refile the corresponding shadowed buffer */
822 jh = commit_transaction->t_shadow_list->b_tprev;
823 bh = jh2bh(jh);
824 clear_buffer_jwrite(bh);
825 J_ASSERT_BH(bh, buffer_jbddirty(bh));
826 J_ASSERT_BH(bh, !buffer_shadow(bh));
827
828 /* The metadata is now released for reuse, but we need
829 to remember it against this transaction so that when
830 we finally commit, we can do any checkpointing
831 required. */
832 JBUFFER_TRACE(jh, "file as BJ_Forget");
833 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
834 JBUFFER_TRACE(jh, "brelse shadowed buffer");
835 __brelse(bh);
836 }
837
838 J_ASSERT (commit_transaction->t_shadow_list == NULL);
839
840 jbd_debug(3, "JBD2: commit phase 4\n");
841
842 /* Here we wait for the revoke record and descriptor record buffers */
843 while (!list_empty(&log_bufs)) {
844 struct buffer_head *bh;
845
846 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
847 wait_on_buffer(bh);
848 cond_resched();
849
850 if (unlikely(!buffer_uptodate(bh)))
851 err = -EIO;
852
853 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
854 clear_buffer_jwrite(bh);
855 jbd2_unfile_log_bh(bh);
856 __brelse(bh); /* One for getblk */
857 /* AKPM: bforget here */
858 }
859
860 if (err)
861 jbd2_journal_abort(journal, err);
862
863 jbd_debug(3, "JBD2: commit phase 5\n");
864 write_lock(&journal->j_state_lock);
865 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
866 commit_transaction->t_state = T_COMMIT_JFLUSH;
867 write_unlock(&journal->j_state_lock);
868
869 if (!jbd2_has_feature_async_commit(journal)) {
870 err = journal_submit_commit_record(journal, commit_transaction,
871 &cbh, crc32_sum);
872 if (err)
873 __jbd2_journal_abort_hard(journal);
874 }
875 if (cbh)
876 err = journal_wait_on_commit_record(journal, cbh);
877 if (jbd2_has_feature_async_commit(journal) &&
878 journal->j_flags & JBD2_BARRIER) {
879 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
880 }
881
882 if (err)
883 jbd2_journal_abort(journal, err);
884
885 /*
886 * Now disk caches for filesystem device are flushed so we are safe to
887 * erase checkpointed transactions from the log by updating journal
888 * superblock.
889 */
890 if (update_tail)
891 jbd2_update_log_tail(journal, first_tid, first_block);
892
893 /* End of a transaction! Finally, we can do checkpoint
894 processing: any buffers committed as a result of this
895 transaction can be removed from any checkpoint list it was on
896 before. */
897
898 jbd_debug(3, "JBD2: commit phase 6\n");
899
900 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
901 J_ASSERT(commit_transaction->t_buffers == NULL);
902 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
903 J_ASSERT(commit_transaction->t_shadow_list == NULL);
904
905restart_loop:
906 /*
907 * As there are other places (journal_unmap_buffer()) adding buffers
908 * to this list we have to be careful and hold the j_list_lock.
909 */
910 spin_lock(&journal->j_list_lock);
911 while (commit_transaction->t_forget) {
912 transaction_t *cp_transaction;
913 struct buffer_head *bh;
914 int try_to_free = 0;
915
916 jh = commit_transaction->t_forget;
917 spin_unlock(&journal->j_list_lock);
918 bh = jh2bh(jh);
919 /*
920 * Get a reference so that bh cannot be freed before we are
921 * done with it.
922 */
923 get_bh(bh);
924 jbd_lock_bh_state(bh);
925 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
926
927 /*
928 * If there is undo-protected committed data against
929 * this buffer, then we can remove it now. If it is a
930 * buffer needing such protection, the old frozen_data
931 * field now points to a committed version of the
932 * buffer, so rotate that field to the new committed
933 * data.
934 *
935 * Otherwise, we can just throw away the frozen data now.
936 *
937 * We also know that the frozen data has already fired
938 * its triggers if they exist, so we can clear that too.
939 */
940 if (jh->b_committed_data) {
941 jbd2_free(jh->b_committed_data, bh->b_size);
942 jh->b_committed_data = NULL;
943 if (jh->b_frozen_data) {
944 jh->b_committed_data = jh->b_frozen_data;
945 jh->b_frozen_data = NULL;
946 jh->b_frozen_triggers = NULL;
947 }
948 } else if (jh->b_frozen_data) {
949 jbd2_free(jh->b_frozen_data, bh->b_size);
950 jh->b_frozen_data = NULL;
951 jh->b_frozen_triggers = NULL;
952 }
953
954 spin_lock(&journal->j_list_lock);
955 cp_transaction = jh->b_cp_transaction;
956 if (cp_transaction) {
957 JBUFFER_TRACE(jh, "remove from old cp transaction");
958 cp_transaction->t_chp_stats.cs_dropped++;
959 __jbd2_journal_remove_checkpoint(jh);
960 }
961
962 /* Only re-checkpoint the buffer_head if it is marked
963 * dirty. If the buffer was added to the BJ_Forget list
964 * by jbd2_journal_forget, it may no longer be dirty and
965 * there's no point in keeping a checkpoint record for
966 * it. */
967
968 /*
969 * A buffer which has been freed while still being journaled by
970 * a previous transaction.
971 */
972 if (buffer_freed(bh)) {
973 /*
974 * If the running transaction is the one containing
975 * "add to orphan" operation (b_next_transaction !=
976 * NULL), we have to wait for that transaction to
977 * commit before we can really get rid of the buffer.
978 * So just clear b_modified to not confuse transaction
979 * credit accounting and refile the buffer to
980 * BJ_Forget of the running transaction. If the just
981 * committed transaction contains "add to orphan"
982 * operation, we can completely invalidate the buffer
983 * now. We are rather through in that since the
984 * buffer may be still accessible when blocksize <
985 * pagesize and it is attached to the last partial
986 * page.
987 */
988 jh->b_modified = 0;
989 if (!jh->b_next_transaction) {
990 clear_buffer_freed(bh);
991 clear_buffer_jbddirty(bh);
992 clear_buffer_mapped(bh);
993 clear_buffer_new(bh);
994 clear_buffer_req(bh);
995 bh->b_bdev = NULL;
996 }
997 }
998
999 if (buffer_jbddirty(bh)) {
1000 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1001 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1002 if (is_journal_aborted(journal))
1003 clear_buffer_jbddirty(bh);
1004 } else {
1005 J_ASSERT_BH(bh, !buffer_dirty(bh));
1006 /*
1007 * The buffer on BJ_Forget list and not jbddirty means
1008 * it has been freed by this transaction and hence it
1009 * could not have been reallocated until this
1010 * transaction has committed. *BUT* it could be
1011 * reallocated once we have written all the data to
1012 * disk and before we process the buffer on BJ_Forget
1013 * list.
1014 */
1015 if (!jh->b_next_transaction)
1016 try_to_free = 1;
1017 }
1018 JBUFFER_TRACE(jh, "refile or unfile buffer");
1019 __jbd2_journal_refile_buffer(jh);
1020 jbd_unlock_bh_state(bh);
1021 if (try_to_free)
1022 release_buffer_page(bh); /* Drops bh reference */
1023 else
1024 __brelse(bh);
1025 cond_resched_lock(&journal->j_list_lock);
1026 }
1027 spin_unlock(&journal->j_list_lock);
1028 /*
1029 * This is a bit sleazy. We use j_list_lock to protect transition
1030 * of a transaction into T_FINISHED state and calling
1031 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1032 * other checkpointing code processing the transaction...
1033 */
1034 write_lock(&journal->j_state_lock);
1035 spin_lock(&journal->j_list_lock);
1036 /*
1037 * Now recheck if some buffers did not get attached to the transaction
1038 * while the lock was dropped...
1039 */
1040 if (commit_transaction->t_forget) {
1041 spin_unlock(&journal->j_list_lock);
1042 write_unlock(&journal->j_state_lock);
1043 goto restart_loop;
1044 }
1045
1046 /* Add the transaction to the checkpoint list
1047 * __journal_remove_checkpoint() can not destroy transaction
1048 * under us because it is not marked as T_FINISHED yet */
1049 if (journal->j_checkpoint_transactions == NULL) {
1050 journal->j_checkpoint_transactions = commit_transaction;
1051 commit_transaction->t_cpnext = commit_transaction;
1052 commit_transaction->t_cpprev = commit_transaction;
1053 } else {
1054 commit_transaction->t_cpnext =
1055 journal->j_checkpoint_transactions;
1056 commit_transaction->t_cpprev =
1057 commit_transaction->t_cpnext->t_cpprev;
1058 commit_transaction->t_cpnext->t_cpprev =
1059 commit_transaction;
1060 commit_transaction->t_cpprev->t_cpnext =
1061 commit_transaction;
1062 }
1063 spin_unlock(&journal->j_list_lock);
1064
1065 /* Done with this transaction! */
1066
1067 jbd_debug(3, "JBD2: commit phase 7\n");
1068
1069 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1070
1071 commit_transaction->t_start = jiffies;
1072 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1073 commit_transaction->t_start);
1074
1075 /*
1076 * File the transaction statistics
1077 */
1078 stats.ts_tid = commit_transaction->t_tid;
1079 stats.run.rs_handle_count =
1080 atomic_read(&commit_transaction->t_handle_count);
1081 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1082 commit_transaction->t_tid, &stats.run);
1083 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1084
1085 commit_transaction->t_state = T_COMMIT_CALLBACK;
1086 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1087 journal->j_commit_sequence = commit_transaction->t_tid;
1088 journal->j_committing_transaction = NULL;
1089 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1090
1091 /*
1092 * weight the commit time higher than the average time so we don't
1093 * react too strongly to vast changes in the commit time
1094 */
1095 if (likely(journal->j_average_commit_time))
1096 journal->j_average_commit_time = (commit_time +
1097 journal->j_average_commit_time*3) / 4;
1098 else
1099 journal->j_average_commit_time = commit_time;
1100
1101 write_unlock(&journal->j_state_lock);
1102
1103 if (journal->j_commit_callback)
1104 journal->j_commit_callback(journal, commit_transaction);
1105
1106 trace_jbd2_end_commit(journal, commit_transaction);
1107 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1108 journal->j_commit_sequence, journal->j_tail_sequence);
1109
1110 write_lock(&journal->j_state_lock);
1111 spin_lock(&journal->j_list_lock);
1112 commit_transaction->t_state = T_FINISHED;
1113 /* Check if the transaction can be dropped now that we are finished */
1114 if (commit_transaction->t_checkpoint_list == NULL &&
1115 commit_transaction->t_checkpoint_io_list == NULL) {
1116 __jbd2_journal_drop_transaction(journal, commit_transaction);
1117 jbd2_journal_free_transaction(commit_transaction);
1118 }
1119 spin_unlock(&journal->j_list_lock);
1120 write_unlock(&journal->j_state_lock);
1121 wake_up(&journal->j_wait_done_commit);
1122
1123 /*
1124 * Calculate overall stats
1125 */
1126 spin_lock(&journal->j_history_lock);
1127 journal->j_stats.ts_tid++;
1128 journal->j_stats.ts_requested += stats.ts_requested;
1129 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1130 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1131 journal->j_stats.run.rs_running += stats.run.rs_running;
1132 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1133 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1134 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1135 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1136 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1137 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1138 spin_unlock(&journal->j_history_lock);
1139}