Loading...
1/*
2 * linux/fs/jbd2/commit.c
3 *
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
5 *
6 * Copyright 1998 Red Hat corp --- All Rights Reserved
7 *
8 * This file is part of the Linux kernel and is made available under
9 * the terms of the GNU General Public License, version 2, or at your
10 * option, any later version, incorporated herein by reference.
11 *
12 * Journal commit routines for the generic filesystem journaling code;
13 * part of the ext2fs journaling system.
14 */
15
16#include <linux/time.h>
17#include <linux/fs.h>
18#include <linux/jbd2.h>
19#include <linux/errno.h>
20#include <linux/slab.h>
21#include <linux/mm.h>
22#include <linux/pagemap.h>
23#include <linux/jiffies.h>
24#include <linux/crc32.h>
25#include <linux/writeback.h>
26#include <linux/backing-dev.h>
27#include <linux/bio.h>
28#include <linux/blkdev.h>
29#include <linux/bitops.h>
30#include <trace/events/jbd2.h>
31
32/*
33 * IO end handler for temporary buffer_heads handling writes to the journal.
34 */
35static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
36{
37 struct buffer_head *orig_bh = bh->b_private;
38
39 BUFFER_TRACE(bh, "");
40 if (uptodate)
41 set_buffer_uptodate(bh);
42 else
43 clear_buffer_uptodate(bh);
44 if (orig_bh) {
45 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
46 smp_mb__after_clear_bit();
47 wake_up_bit(&orig_bh->b_state, BH_Shadow);
48 }
49 unlock_buffer(bh);
50}
51
52/*
53 * When an ext4 file is truncated, it is possible that some pages are not
54 * successfully freed, because they are attached to a committing transaction.
55 * After the transaction commits, these pages are left on the LRU, with no
56 * ->mapping, and with attached buffers. These pages are trivially reclaimable
57 * by the VM, but their apparent absence upsets the VM accounting, and it makes
58 * the numbers in /proc/meminfo look odd.
59 *
60 * So here, we have a buffer which has just come off the forget list. Look to
61 * see if we can strip all buffers from the backing page.
62 *
63 * Called under lock_journal(), and possibly under journal_datalist_lock. The
64 * caller provided us with a ref against the buffer, and we drop that here.
65 */
66static void release_buffer_page(struct buffer_head *bh)
67{
68 struct page *page;
69
70 if (buffer_dirty(bh))
71 goto nope;
72 if (atomic_read(&bh->b_count) != 1)
73 goto nope;
74 page = bh->b_page;
75 if (!page)
76 goto nope;
77 if (page->mapping)
78 goto nope;
79
80 /* OK, it's a truncated page */
81 if (!trylock_page(page))
82 goto nope;
83
84 page_cache_get(page);
85 __brelse(bh);
86 try_to_free_buffers(page);
87 unlock_page(page);
88 page_cache_release(page);
89 return;
90
91nope:
92 __brelse(bh);
93}
94
95static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
96{
97 struct commit_header *h;
98 __u32 csum;
99
100 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
101 return;
102
103 h = (struct commit_header *)(bh->b_data);
104 h->h_chksum_type = 0;
105 h->h_chksum_size = 0;
106 h->h_chksum[0] = 0;
107 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
108 h->h_chksum[0] = cpu_to_be32(csum);
109}
110
111/*
112 * Done it all: now submit the commit record. We should have
113 * cleaned up our previous buffers by now, so if we are in abort
114 * mode we can now just skip the rest of the journal write
115 * entirely.
116 *
117 * Returns 1 if the journal needs to be aborted or 0 on success
118 */
119static int journal_submit_commit_record(journal_t *journal,
120 transaction_t *commit_transaction,
121 struct buffer_head **cbh,
122 __u32 crc32_sum)
123{
124 struct commit_header *tmp;
125 struct buffer_head *bh;
126 int ret;
127 struct timespec now = current_kernel_time();
128
129 *cbh = NULL;
130
131 if (is_journal_aborted(journal))
132 return 0;
133
134 bh = jbd2_journal_get_descriptor_buffer(journal);
135 if (!bh)
136 return 1;
137
138 tmp = (struct commit_header *)bh->b_data;
139 tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
140 tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK);
141 tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
142 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
143 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
144
145 if (JBD2_HAS_COMPAT_FEATURE(journal,
146 JBD2_FEATURE_COMPAT_CHECKSUM)) {
147 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
148 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
149 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
150 }
151 jbd2_commit_block_csum_set(journal, bh);
152
153 BUFFER_TRACE(bh, "submit commit block");
154 lock_buffer(bh);
155 clear_buffer_dirty(bh);
156 set_buffer_uptodate(bh);
157 bh->b_end_io = journal_end_buffer_io_sync;
158
159 if (journal->j_flags & JBD2_BARRIER &&
160 !JBD2_HAS_INCOMPAT_FEATURE(journal,
161 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT))
162 ret = submit_bh(WRITE_SYNC | WRITE_FLUSH_FUA, bh);
163 else
164 ret = submit_bh(WRITE_SYNC, bh);
165
166 *cbh = bh;
167 return ret;
168}
169
170/*
171 * This function along with journal_submit_commit_record
172 * allows to write the commit record asynchronously.
173 */
174static int journal_wait_on_commit_record(journal_t *journal,
175 struct buffer_head *bh)
176{
177 int ret = 0;
178
179 clear_buffer_dirty(bh);
180 wait_on_buffer(bh);
181
182 if (unlikely(!buffer_uptodate(bh)))
183 ret = -EIO;
184 put_bh(bh); /* One for getblk() */
185
186 return ret;
187}
188
189/*
190 * write the filemap data using writepage() address_space_operations.
191 * We don't do block allocation here even for delalloc. We don't
192 * use writepages() because with dealyed allocation we may be doing
193 * block allocation in writepages().
194 */
195static int journal_submit_inode_data_buffers(struct address_space *mapping)
196{
197 int ret;
198 struct writeback_control wbc = {
199 .sync_mode = WB_SYNC_ALL,
200 .nr_to_write = mapping->nrpages * 2,
201 .range_start = 0,
202 .range_end = i_size_read(mapping->host),
203 };
204
205 ret = generic_writepages(mapping, &wbc);
206 return ret;
207}
208
209/*
210 * Submit all the data buffers of inode associated with the transaction to
211 * disk.
212 *
213 * We are in a committing transaction. Therefore no new inode can be added to
214 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
215 * operate on from being released while we write out pages.
216 */
217static int journal_submit_data_buffers(journal_t *journal,
218 transaction_t *commit_transaction)
219{
220 struct jbd2_inode *jinode;
221 int err, ret = 0;
222 struct address_space *mapping;
223
224 spin_lock(&journal->j_list_lock);
225 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
226 mapping = jinode->i_vfs_inode->i_mapping;
227 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
228 spin_unlock(&journal->j_list_lock);
229 /*
230 * submit the inode data buffers. We use writepage
231 * instead of writepages. Because writepages can do
232 * block allocation with delalloc. We need to write
233 * only allocated blocks here.
234 */
235 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
236 err = journal_submit_inode_data_buffers(mapping);
237 if (!ret)
238 ret = err;
239 spin_lock(&journal->j_list_lock);
240 J_ASSERT(jinode->i_transaction == commit_transaction);
241 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
242 smp_mb__after_clear_bit();
243 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
244 }
245 spin_unlock(&journal->j_list_lock);
246 return ret;
247}
248
249/*
250 * Wait for data submitted for writeout, refile inodes to proper
251 * transaction if needed.
252 *
253 */
254static int journal_finish_inode_data_buffers(journal_t *journal,
255 transaction_t *commit_transaction)
256{
257 struct jbd2_inode *jinode, *next_i;
258 int err, ret = 0;
259
260 /* For locking, see the comment in journal_submit_data_buffers() */
261 spin_lock(&journal->j_list_lock);
262 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
263 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
264 spin_unlock(&journal->j_list_lock);
265 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
266 if (err) {
267 /*
268 * Because AS_EIO is cleared by
269 * filemap_fdatawait_range(), set it again so
270 * that user process can get -EIO from fsync().
271 */
272 set_bit(AS_EIO,
273 &jinode->i_vfs_inode->i_mapping->flags);
274
275 if (!ret)
276 ret = err;
277 }
278 spin_lock(&journal->j_list_lock);
279 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
280 smp_mb__after_clear_bit();
281 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
282 }
283
284 /* Now refile inode to proper lists */
285 list_for_each_entry_safe(jinode, next_i,
286 &commit_transaction->t_inode_list, i_list) {
287 list_del(&jinode->i_list);
288 if (jinode->i_next_transaction) {
289 jinode->i_transaction = jinode->i_next_transaction;
290 jinode->i_next_transaction = NULL;
291 list_add(&jinode->i_list,
292 &jinode->i_transaction->t_inode_list);
293 } else {
294 jinode->i_transaction = NULL;
295 }
296 }
297 spin_unlock(&journal->j_list_lock);
298
299 return ret;
300}
301
302static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
303{
304 struct page *page = bh->b_page;
305 char *addr;
306 __u32 checksum;
307
308 addr = kmap_atomic(page);
309 checksum = crc32_be(crc32_sum,
310 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
311 kunmap_atomic(addr);
312
313 return checksum;
314}
315
316static void write_tag_block(int tag_bytes, journal_block_tag_t *tag,
317 unsigned long long block)
318{
319 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
320 if (tag_bytes > JBD2_TAG_SIZE32)
321 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
322}
323
324static void jbd2_descr_block_csum_set(journal_t *j,
325 struct buffer_head *bh)
326{
327 struct jbd2_journal_block_tail *tail;
328 __u32 csum;
329
330 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
331 return;
332
333 tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize -
334 sizeof(struct jbd2_journal_block_tail));
335 tail->t_checksum = 0;
336 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
337 tail->t_checksum = cpu_to_be32(csum);
338}
339
340static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
341 struct buffer_head *bh, __u32 sequence)
342{
343 struct page *page = bh->b_page;
344 __u8 *addr;
345 __u32 csum32;
346 __be32 seq;
347
348 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
349 return;
350
351 seq = cpu_to_be32(sequence);
352 addr = kmap_atomic(page);
353 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
354 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
355 bh->b_size);
356 kunmap_atomic(addr);
357
358 /* We only have space to store the lower 16 bits of the crc32c. */
359 tag->t_checksum = cpu_to_be16(csum32);
360}
361/*
362 * jbd2_journal_commit_transaction
363 *
364 * The primary function for committing a transaction to the log. This
365 * function is called by the journal thread to begin a complete commit.
366 */
367void jbd2_journal_commit_transaction(journal_t *journal)
368{
369 struct transaction_stats_s stats;
370 transaction_t *commit_transaction;
371 struct journal_head *jh;
372 struct buffer_head *descriptor;
373 struct buffer_head **wbuf = journal->j_wbuf;
374 int bufs;
375 int flags;
376 int err;
377 unsigned long long blocknr;
378 ktime_t start_time;
379 u64 commit_time;
380 char *tagp = NULL;
381 journal_header_t *header;
382 journal_block_tag_t *tag = NULL;
383 int space_left = 0;
384 int first_tag = 0;
385 int tag_flag;
386 int i;
387 int tag_bytes = journal_tag_bytes(journal);
388 struct buffer_head *cbh = NULL; /* For transactional checksums */
389 __u32 crc32_sum = ~0;
390 struct blk_plug plug;
391 /* Tail of the journal */
392 unsigned long first_block;
393 tid_t first_tid;
394 int update_tail;
395 int csum_size = 0;
396 LIST_HEAD(io_bufs);
397 LIST_HEAD(log_bufs);
398
399 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
400 csum_size = sizeof(struct jbd2_journal_block_tail);
401
402 /*
403 * First job: lock down the current transaction and wait for
404 * all outstanding updates to complete.
405 */
406
407 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
408 if (journal->j_flags & JBD2_FLUSHED) {
409 jbd_debug(3, "super block updated\n");
410 mutex_lock(&journal->j_checkpoint_mutex);
411 /*
412 * We hold j_checkpoint_mutex so tail cannot change under us.
413 * We don't need any special data guarantees for writing sb
414 * since journal is empty and it is ok for write to be
415 * flushed only with transaction commit.
416 */
417 jbd2_journal_update_sb_log_tail(journal,
418 journal->j_tail_sequence,
419 journal->j_tail,
420 WRITE_SYNC);
421 mutex_unlock(&journal->j_checkpoint_mutex);
422 } else {
423 jbd_debug(3, "superblock not updated\n");
424 }
425
426 J_ASSERT(journal->j_running_transaction != NULL);
427 J_ASSERT(journal->j_committing_transaction == NULL);
428
429 commit_transaction = journal->j_running_transaction;
430
431 trace_jbd2_start_commit(journal, commit_transaction);
432 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
433 commit_transaction->t_tid);
434
435 write_lock(&journal->j_state_lock);
436 J_ASSERT(commit_transaction->t_state == T_RUNNING);
437 commit_transaction->t_state = T_LOCKED;
438
439 trace_jbd2_commit_locking(journal, commit_transaction);
440 stats.run.rs_wait = commit_transaction->t_max_wait;
441 stats.run.rs_request_delay = 0;
442 stats.run.rs_locked = jiffies;
443 if (commit_transaction->t_requested)
444 stats.run.rs_request_delay =
445 jbd2_time_diff(commit_transaction->t_requested,
446 stats.run.rs_locked);
447 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
448 stats.run.rs_locked);
449
450 spin_lock(&commit_transaction->t_handle_lock);
451 while (atomic_read(&commit_transaction->t_updates)) {
452 DEFINE_WAIT(wait);
453
454 prepare_to_wait(&journal->j_wait_updates, &wait,
455 TASK_UNINTERRUPTIBLE);
456 if (atomic_read(&commit_transaction->t_updates)) {
457 spin_unlock(&commit_transaction->t_handle_lock);
458 write_unlock(&journal->j_state_lock);
459 schedule();
460 write_lock(&journal->j_state_lock);
461 spin_lock(&commit_transaction->t_handle_lock);
462 }
463 finish_wait(&journal->j_wait_updates, &wait);
464 }
465 spin_unlock(&commit_transaction->t_handle_lock);
466
467 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
468 journal->j_max_transaction_buffers);
469
470 /*
471 * First thing we are allowed to do is to discard any remaining
472 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
473 * that there are no such buffers: if a large filesystem
474 * operation like a truncate needs to split itself over multiple
475 * transactions, then it may try to do a jbd2_journal_restart() while
476 * there are still BJ_Reserved buffers outstanding. These must
477 * be released cleanly from the current transaction.
478 *
479 * In this case, the filesystem must still reserve write access
480 * again before modifying the buffer in the new transaction, but
481 * we do not require it to remember exactly which old buffers it
482 * has reserved. This is consistent with the existing behaviour
483 * that multiple jbd2_journal_get_write_access() calls to the same
484 * buffer are perfectly permissible.
485 */
486 while (commit_transaction->t_reserved_list) {
487 jh = commit_transaction->t_reserved_list;
488 JBUFFER_TRACE(jh, "reserved, unused: refile");
489 /*
490 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
491 * leave undo-committed data.
492 */
493 if (jh->b_committed_data) {
494 struct buffer_head *bh = jh2bh(jh);
495
496 jbd_lock_bh_state(bh);
497 jbd2_free(jh->b_committed_data, bh->b_size);
498 jh->b_committed_data = NULL;
499 jbd_unlock_bh_state(bh);
500 }
501 jbd2_journal_refile_buffer(journal, jh);
502 }
503
504 /*
505 * Now try to drop any written-back buffers from the journal's
506 * checkpoint lists. We do this *before* commit because it potentially
507 * frees some memory
508 */
509 spin_lock(&journal->j_list_lock);
510 __jbd2_journal_clean_checkpoint_list(journal);
511 spin_unlock(&journal->j_list_lock);
512
513 jbd_debug(3, "JBD2: commit phase 1\n");
514
515 /*
516 * Clear revoked flag to reflect there is no revoked buffers
517 * in the next transaction which is going to be started.
518 */
519 jbd2_clear_buffer_revoked_flags(journal);
520
521 /*
522 * Switch to a new revoke table.
523 */
524 jbd2_journal_switch_revoke_table(journal);
525
526 /*
527 * Reserved credits cannot be claimed anymore, free them
528 */
529 atomic_sub(atomic_read(&journal->j_reserved_credits),
530 &commit_transaction->t_outstanding_credits);
531
532 trace_jbd2_commit_flushing(journal, commit_transaction);
533 stats.run.rs_flushing = jiffies;
534 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
535 stats.run.rs_flushing);
536
537 commit_transaction->t_state = T_FLUSH;
538 journal->j_committing_transaction = commit_transaction;
539 journal->j_running_transaction = NULL;
540 start_time = ktime_get();
541 commit_transaction->t_log_start = journal->j_head;
542 wake_up(&journal->j_wait_transaction_locked);
543 write_unlock(&journal->j_state_lock);
544
545 jbd_debug(3, "JBD2: commit phase 2a\n");
546
547 /*
548 * Now start flushing things to disk, in the order they appear
549 * on the transaction lists. Data blocks go first.
550 */
551 err = journal_submit_data_buffers(journal, commit_transaction);
552 if (err)
553 jbd2_journal_abort(journal, err);
554
555 blk_start_plug(&plug);
556 jbd2_journal_write_revoke_records(journal, commit_transaction,
557 &log_bufs, WRITE_SYNC);
558
559 jbd_debug(3, "JBD2: commit phase 2b\n");
560
561 /*
562 * Way to go: we have now written out all of the data for a
563 * transaction! Now comes the tricky part: we need to write out
564 * metadata. Loop over the transaction's entire buffer list:
565 */
566 write_lock(&journal->j_state_lock);
567 commit_transaction->t_state = T_COMMIT;
568 write_unlock(&journal->j_state_lock);
569
570 trace_jbd2_commit_logging(journal, commit_transaction);
571 stats.run.rs_logging = jiffies;
572 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
573 stats.run.rs_logging);
574 stats.run.rs_blocks =
575 atomic_read(&commit_transaction->t_outstanding_credits);
576 stats.run.rs_blocks_logged = 0;
577
578 J_ASSERT(commit_transaction->t_nr_buffers <=
579 atomic_read(&commit_transaction->t_outstanding_credits));
580
581 err = 0;
582 bufs = 0;
583 descriptor = NULL;
584 while (commit_transaction->t_buffers) {
585
586 /* Find the next buffer to be journaled... */
587
588 jh = commit_transaction->t_buffers;
589
590 /* If we're in abort mode, we just un-journal the buffer and
591 release it. */
592
593 if (is_journal_aborted(journal)) {
594 clear_buffer_jbddirty(jh2bh(jh));
595 JBUFFER_TRACE(jh, "journal is aborting: refile");
596 jbd2_buffer_abort_trigger(jh,
597 jh->b_frozen_data ?
598 jh->b_frozen_triggers :
599 jh->b_triggers);
600 jbd2_journal_refile_buffer(journal, jh);
601 /* If that was the last one, we need to clean up
602 * any descriptor buffers which may have been
603 * already allocated, even if we are now
604 * aborting. */
605 if (!commit_transaction->t_buffers)
606 goto start_journal_io;
607 continue;
608 }
609
610 /* Make sure we have a descriptor block in which to
611 record the metadata buffer. */
612
613 if (!descriptor) {
614 J_ASSERT (bufs == 0);
615
616 jbd_debug(4, "JBD2: get descriptor\n");
617
618 descriptor = jbd2_journal_get_descriptor_buffer(journal);
619 if (!descriptor) {
620 jbd2_journal_abort(journal, -EIO);
621 continue;
622 }
623
624 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
625 (unsigned long long)descriptor->b_blocknr,
626 descriptor->b_data);
627 header = (journal_header_t *)descriptor->b_data;
628 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
629 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK);
630 header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
631
632 tagp = &descriptor->b_data[sizeof(journal_header_t)];
633 space_left = descriptor->b_size -
634 sizeof(journal_header_t);
635 first_tag = 1;
636 set_buffer_jwrite(descriptor);
637 set_buffer_dirty(descriptor);
638 wbuf[bufs++] = descriptor;
639
640 /* Record it so that we can wait for IO
641 completion later */
642 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
643 jbd2_file_log_bh(&log_bufs, descriptor);
644 }
645
646 /* Where is the buffer to be written? */
647
648 err = jbd2_journal_next_log_block(journal, &blocknr);
649 /* If the block mapping failed, just abandon the buffer
650 and repeat this loop: we'll fall into the
651 refile-on-abort condition above. */
652 if (err) {
653 jbd2_journal_abort(journal, err);
654 continue;
655 }
656
657 /*
658 * start_this_handle() uses t_outstanding_credits to determine
659 * the free space in the log, but this counter is changed
660 * by jbd2_journal_next_log_block() also.
661 */
662 atomic_dec(&commit_transaction->t_outstanding_credits);
663
664 /* Bump b_count to prevent truncate from stumbling over
665 the shadowed buffer! @@@ This can go if we ever get
666 rid of the shadow pairing of buffers. */
667 atomic_inc(&jh2bh(jh)->b_count);
668
669 /*
670 * Make a temporary IO buffer with which to write it out
671 * (this will requeue the metadata buffer to BJ_Shadow).
672 */
673 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
674 JBUFFER_TRACE(jh, "ph3: write metadata");
675 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
676 jh, &wbuf[bufs], blocknr);
677 if (flags < 0) {
678 jbd2_journal_abort(journal, flags);
679 continue;
680 }
681 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
682
683 /* Record the new block's tag in the current descriptor
684 buffer */
685
686 tag_flag = 0;
687 if (flags & 1)
688 tag_flag |= JBD2_FLAG_ESCAPE;
689 if (!first_tag)
690 tag_flag |= JBD2_FLAG_SAME_UUID;
691
692 tag = (journal_block_tag_t *) tagp;
693 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr);
694 tag->t_flags = cpu_to_be16(tag_flag);
695 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
696 commit_transaction->t_tid);
697 tagp += tag_bytes;
698 space_left -= tag_bytes;
699 bufs++;
700
701 if (first_tag) {
702 memcpy (tagp, journal->j_uuid, 16);
703 tagp += 16;
704 space_left -= 16;
705 first_tag = 0;
706 }
707
708 /* If there's no more to do, or if the descriptor is full,
709 let the IO rip! */
710
711 if (bufs == journal->j_wbufsize ||
712 commit_transaction->t_buffers == NULL ||
713 space_left < tag_bytes + 16 + csum_size) {
714
715 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
716
717 /* Write an end-of-descriptor marker before
718 submitting the IOs. "tag" still points to
719 the last tag we set up. */
720
721 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
722
723 jbd2_descr_block_csum_set(journal, descriptor);
724start_journal_io:
725 for (i = 0; i < bufs; i++) {
726 struct buffer_head *bh = wbuf[i];
727 /*
728 * Compute checksum.
729 */
730 if (JBD2_HAS_COMPAT_FEATURE(journal,
731 JBD2_FEATURE_COMPAT_CHECKSUM)) {
732 crc32_sum =
733 jbd2_checksum_data(crc32_sum, bh);
734 }
735
736 lock_buffer(bh);
737 clear_buffer_dirty(bh);
738 set_buffer_uptodate(bh);
739 bh->b_end_io = journal_end_buffer_io_sync;
740 submit_bh(WRITE_SYNC, bh);
741 }
742 cond_resched();
743 stats.run.rs_blocks_logged += bufs;
744
745 /* Force a new descriptor to be generated next
746 time round the loop. */
747 descriptor = NULL;
748 bufs = 0;
749 }
750 }
751
752 err = journal_finish_inode_data_buffers(journal, commit_transaction);
753 if (err) {
754 printk(KERN_WARNING
755 "JBD2: Detected IO errors while flushing file data "
756 "on %s\n", journal->j_devname);
757 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
758 jbd2_journal_abort(journal, err);
759 err = 0;
760 }
761
762 /*
763 * Get current oldest transaction in the log before we issue flush
764 * to the filesystem device. After the flush we can be sure that
765 * blocks of all older transactions are checkpointed to persistent
766 * storage and we will be safe to update journal start in the
767 * superblock with the numbers we get here.
768 */
769 update_tail =
770 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
771
772 write_lock(&journal->j_state_lock);
773 if (update_tail) {
774 long freed = first_block - journal->j_tail;
775
776 if (first_block < journal->j_tail)
777 freed += journal->j_last - journal->j_first;
778 /* Update tail only if we free significant amount of space */
779 if (freed < journal->j_maxlen / 4)
780 update_tail = 0;
781 }
782 J_ASSERT(commit_transaction->t_state == T_COMMIT);
783 commit_transaction->t_state = T_COMMIT_DFLUSH;
784 write_unlock(&journal->j_state_lock);
785
786 /*
787 * If the journal is not located on the file system device,
788 * then we must flush the file system device before we issue
789 * the commit record
790 */
791 if (commit_transaction->t_need_data_flush &&
792 (journal->j_fs_dev != journal->j_dev) &&
793 (journal->j_flags & JBD2_BARRIER))
794 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
795
796 /* Done it all: now write the commit record asynchronously. */
797 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
798 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
799 err = journal_submit_commit_record(journal, commit_transaction,
800 &cbh, crc32_sum);
801 if (err)
802 __jbd2_journal_abort_hard(journal);
803 }
804
805 blk_finish_plug(&plug);
806
807 /* Lo and behold: we have just managed to send a transaction to
808 the log. Before we can commit it, wait for the IO so far to
809 complete. Control buffers being written are on the
810 transaction's t_log_list queue, and metadata buffers are on
811 the io_bufs list.
812
813 Wait for the buffers in reverse order. That way we are
814 less likely to be woken up until all IOs have completed, and
815 so we incur less scheduling load.
816 */
817
818 jbd_debug(3, "JBD2: commit phase 3\n");
819
820 while (!list_empty(&io_bufs)) {
821 struct buffer_head *bh = list_entry(io_bufs.prev,
822 struct buffer_head,
823 b_assoc_buffers);
824
825 wait_on_buffer(bh);
826 cond_resched();
827
828 if (unlikely(!buffer_uptodate(bh)))
829 err = -EIO;
830 jbd2_unfile_log_bh(bh);
831
832 /*
833 * The list contains temporary buffer heads created by
834 * jbd2_journal_write_metadata_buffer().
835 */
836 BUFFER_TRACE(bh, "dumping temporary bh");
837 __brelse(bh);
838 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
839 free_buffer_head(bh);
840
841 /* We also have to refile the corresponding shadowed buffer */
842 jh = commit_transaction->t_shadow_list->b_tprev;
843 bh = jh2bh(jh);
844 clear_buffer_jwrite(bh);
845 J_ASSERT_BH(bh, buffer_jbddirty(bh));
846 J_ASSERT_BH(bh, !buffer_shadow(bh));
847
848 /* The metadata is now released for reuse, but we need
849 to remember it against this transaction so that when
850 we finally commit, we can do any checkpointing
851 required. */
852 JBUFFER_TRACE(jh, "file as BJ_Forget");
853 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
854 JBUFFER_TRACE(jh, "brelse shadowed buffer");
855 __brelse(bh);
856 }
857
858 J_ASSERT (commit_transaction->t_shadow_list == NULL);
859
860 jbd_debug(3, "JBD2: commit phase 4\n");
861
862 /* Here we wait for the revoke record and descriptor record buffers */
863 while (!list_empty(&log_bufs)) {
864 struct buffer_head *bh;
865
866 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
867 wait_on_buffer(bh);
868 cond_resched();
869
870 if (unlikely(!buffer_uptodate(bh)))
871 err = -EIO;
872
873 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
874 clear_buffer_jwrite(bh);
875 jbd2_unfile_log_bh(bh);
876 __brelse(bh); /* One for getblk */
877 /* AKPM: bforget here */
878 }
879
880 if (err)
881 jbd2_journal_abort(journal, err);
882
883 jbd_debug(3, "JBD2: commit phase 5\n");
884 write_lock(&journal->j_state_lock);
885 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
886 commit_transaction->t_state = T_COMMIT_JFLUSH;
887 write_unlock(&journal->j_state_lock);
888
889 if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
890 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
891 err = journal_submit_commit_record(journal, commit_transaction,
892 &cbh, crc32_sum);
893 if (err)
894 __jbd2_journal_abort_hard(journal);
895 }
896 if (cbh)
897 err = journal_wait_on_commit_record(journal, cbh);
898 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
899 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) &&
900 journal->j_flags & JBD2_BARRIER) {
901 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
902 }
903
904 if (err)
905 jbd2_journal_abort(journal, err);
906
907 /*
908 * Now disk caches for filesystem device are flushed so we are safe to
909 * erase checkpointed transactions from the log by updating journal
910 * superblock.
911 */
912 if (update_tail)
913 jbd2_update_log_tail(journal, first_tid, first_block);
914
915 /* End of a transaction! Finally, we can do checkpoint
916 processing: any buffers committed as a result of this
917 transaction can be removed from any checkpoint list it was on
918 before. */
919
920 jbd_debug(3, "JBD2: commit phase 6\n");
921
922 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
923 J_ASSERT(commit_transaction->t_buffers == NULL);
924 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
925 J_ASSERT(commit_transaction->t_shadow_list == NULL);
926
927restart_loop:
928 /*
929 * As there are other places (journal_unmap_buffer()) adding buffers
930 * to this list we have to be careful and hold the j_list_lock.
931 */
932 spin_lock(&journal->j_list_lock);
933 while (commit_transaction->t_forget) {
934 transaction_t *cp_transaction;
935 struct buffer_head *bh;
936 int try_to_free = 0;
937
938 jh = commit_transaction->t_forget;
939 spin_unlock(&journal->j_list_lock);
940 bh = jh2bh(jh);
941 /*
942 * Get a reference so that bh cannot be freed before we are
943 * done with it.
944 */
945 get_bh(bh);
946 jbd_lock_bh_state(bh);
947 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
948
949 /*
950 * If there is undo-protected committed data against
951 * this buffer, then we can remove it now. If it is a
952 * buffer needing such protection, the old frozen_data
953 * field now points to a committed version of the
954 * buffer, so rotate that field to the new committed
955 * data.
956 *
957 * Otherwise, we can just throw away the frozen data now.
958 *
959 * We also know that the frozen data has already fired
960 * its triggers if they exist, so we can clear that too.
961 */
962 if (jh->b_committed_data) {
963 jbd2_free(jh->b_committed_data, bh->b_size);
964 jh->b_committed_data = NULL;
965 if (jh->b_frozen_data) {
966 jh->b_committed_data = jh->b_frozen_data;
967 jh->b_frozen_data = NULL;
968 jh->b_frozen_triggers = NULL;
969 }
970 } else if (jh->b_frozen_data) {
971 jbd2_free(jh->b_frozen_data, bh->b_size);
972 jh->b_frozen_data = NULL;
973 jh->b_frozen_triggers = NULL;
974 }
975
976 spin_lock(&journal->j_list_lock);
977 cp_transaction = jh->b_cp_transaction;
978 if (cp_transaction) {
979 JBUFFER_TRACE(jh, "remove from old cp transaction");
980 cp_transaction->t_chp_stats.cs_dropped++;
981 __jbd2_journal_remove_checkpoint(jh);
982 }
983
984 /* Only re-checkpoint the buffer_head if it is marked
985 * dirty. If the buffer was added to the BJ_Forget list
986 * by jbd2_journal_forget, it may no longer be dirty and
987 * there's no point in keeping a checkpoint record for
988 * it. */
989
990 /*
991 * A buffer which has been freed while still being journaled by
992 * a previous transaction.
993 */
994 if (buffer_freed(bh)) {
995 /*
996 * If the running transaction is the one containing
997 * "add to orphan" operation (b_next_transaction !=
998 * NULL), we have to wait for that transaction to
999 * commit before we can really get rid of the buffer.
1000 * So just clear b_modified to not confuse transaction
1001 * credit accounting and refile the buffer to
1002 * BJ_Forget of the running transaction. If the just
1003 * committed transaction contains "add to orphan"
1004 * operation, we can completely invalidate the buffer
1005 * now. We are rather through in that since the
1006 * buffer may be still accessible when blocksize <
1007 * pagesize and it is attached to the last partial
1008 * page.
1009 */
1010 jh->b_modified = 0;
1011 if (!jh->b_next_transaction) {
1012 clear_buffer_freed(bh);
1013 clear_buffer_jbddirty(bh);
1014 clear_buffer_mapped(bh);
1015 clear_buffer_new(bh);
1016 clear_buffer_req(bh);
1017 bh->b_bdev = NULL;
1018 }
1019 }
1020
1021 if (buffer_jbddirty(bh)) {
1022 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1023 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1024 if (is_journal_aborted(journal))
1025 clear_buffer_jbddirty(bh);
1026 } else {
1027 J_ASSERT_BH(bh, !buffer_dirty(bh));
1028 /*
1029 * The buffer on BJ_Forget list and not jbddirty means
1030 * it has been freed by this transaction and hence it
1031 * could not have been reallocated until this
1032 * transaction has committed. *BUT* it could be
1033 * reallocated once we have written all the data to
1034 * disk and before we process the buffer on BJ_Forget
1035 * list.
1036 */
1037 if (!jh->b_next_transaction)
1038 try_to_free = 1;
1039 }
1040 JBUFFER_TRACE(jh, "refile or unfile buffer");
1041 __jbd2_journal_refile_buffer(jh);
1042 jbd_unlock_bh_state(bh);
1043 if (try_to_free)
1044 release_buffer_page(bh); /* Drops bh reference */
1045 else
1046 __brelse(bh);
1047 cond_resched_lock(&journal->j_list_lock);
1048 }
1049 spin_unlock(&journal->j_list_lock);
1050 /*
1051 * This is a bit sleazy. We use j_list_lock to protect transition
1052 * of a transaction into T_FINISHED state and calling
1053 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1054 * other checkpointing code processing the transaction...
1055 */
1056 write_lock(&journal->j_state_lock);
1057 spin_lock(&journal->j_list_lock);
1058 /*
1059 * Now recheck if some buffers did not get attached to the transaction
1060 * while the lock was dropped...
1061 */
1062 if (commit_transaction->t_forget) {
1063 spin_unlock(&journal->j_list_lock);
1064 write_unlock(&journal->j_state_lock);
1065 goto restart_loop;
1066 }
1067
1068 /* Add the transaction to the checkpoint list
1069 * __journal_remove_checkpoint() can not destroy transaction
1070 * under us because it is not marked as T_FINISHED yet */
1071 if (journal->j_checkpoint_transactions == NULL) {
1072 journal->j_checkpoint_transactions = commit_transaction;
1073 commit_transaction->t_cpnext = commit_transaction;
1074 commit_transaction->t_cpprev = commit_transaction;
1075 } else {
1076 commit_transaction->t_cpnext =
1077 journal->j_checkpoint_transactions;
1078 commit_transaction->t_cpprev =
1079 commit_transaction->t_cpnext->t_cpprev;
1080 commit_transaction->t_cpnext->t_cpprev =
1081 commit_transaction;
1082 commit_transaction->t_cpprev->t_cpnext =
1083 commit_transaction;
1084 }
1085 spin_unlock(&journal->j_list_lock);
1086
1087 /* Done with this transaction! */
1088
1089 jbd_debug(3, "JBD2: commit phase 7\n");
1090
1091 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1092
1093 commit_transaction->t_start = jiffies;
1094 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1095 commit_transaction->t_start);
1096
1097 /*
1098 * File the transaction statistics
1099 */
1100 stats.ts_tid = commit_transaction->t_tid;
1101 stats.run.rs_handle_count =
1102 atomic_read(&commit_transaction->t_handle_count);
1103 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1104 commit_transaction->t_tid, &stats.run);
1105 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1106
1107 commit_transaction->t_state = T_COMMIT_CALLBACK;
1108 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1109 journal->j_commit_sequence = commit_transaction->t_tid;
1110 journal->j_committing_transaction = NULL;
1111 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1112
1113 /*
1114 * weight the commit time higher than the average time so we don't
1115 * react too strongly to vast changes in the commit time
1116 */
1117 if (likely(journal->j_average_commit_time))
1118 journal->j_average_commit_time = (commit_time +
1119 journal->j_average_commit_time*3) / 4;
1120 else
1121 journal->j_average_commit_time = commit_time;
1122
1123 write_unlock(&journal->j_state_lock);
1124
1125 if (journal->j_commit_callback)
1126 journal->j_commit_callback(journal, commit_transaction);
1127
1128 trace_jbd2_end_commit(journal, commit_transaction);
1129 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1130 journal->j_commit_sequence, journal->j_tail_sequence);
1131
1132 write_lock(&journal->j_state_lock);
1133 spin_lock(&journal->j_list_lock);
1134 commit_transaction->t_state = T_FINISHED;
1135 /* Check if the transaction can be dropped now that we are finished */
1136 if (commit_transaction->t_checkpoint_list == NULL &&
1137 commit_transaction->t_checkpoint_io_list == NULL) {
1138 __jbd2_journal_drop_transaction(journal, commit_transaction);
1139 jbd2_journal_free_transaction(commit_transaction);
1140 }
1141 spin_unlock(&journal->j_list_lock);
1142 write_unlock(&journal->j_state_lock);
1143 wake_up(&journal->j_wait_done_commit);
1144
1145 /*
1146 * Calculate overall stats
1147 */
1148 spin_lock(&journal->j_history_lock);
1149 journal->j_stats.ts_tid++;
1150 journal->j_stats.ts_requested += stats.ts_requested;
1151 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1152 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1153 journal->j_stats.run.rs_running += stats.run.rs_running;
1154 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1155 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1156 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1157 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1158 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1159 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1160 spin_unlock(&journal->j_history_lock);
1161}
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * linux/fs/jbd2/commit.c
4 *
5 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
6 *
7 * Copyright 1998 Red Hat corp --- All Rights Reserved
8 *
9 * Journal commit routines for the generic filesystem journaling code;
10 * part of the ext2fs journaling system.
11 */
12
13#include <linux/time.h>
14#include <linux/fs.h>
15#include <linux/jbd2.h>
16#include <linux/errno.h>
17#include <linux/slab.h>
18#include <linux/mm.h>
19#include <linux/pagemap.h>
20#include <linux/jiffies.h>
21#include <linux/crc32.h>
22#include <linux/writeback.h>
23#include <linux/backing-dev.h>
24#include <linux/bio.h>
25#include <linux/blkdev.h>
26#include <linux/bitops.h>
27#include <trace/events/jbd2.h>
28
29/*
30 * IO end handler for temporary buffer_heads handling writes to the journal.
31 */
32static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
33{
34 struct buffer_head *orig_bh = bh->b_private;
35
36 BUFFER_TRACE(bh, "");
37 if (uptodate)
38 set_buffer_uptodate(bh);
39 else
40 clear_buffer_uptodate(bh);
41 if (orig_bh) {
42 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
43 smp_mb__after_atomic();
44 wake_up_bit(&orig_bh->b_state, BH_Shadow);
45 }
46 unlock_buffer(bh);
47}
48
49/*
50 * When an ext4 file is truncated, it is possible that some pages are not
51 * successfully freed, because they are attached to a committing transaction.
52 * After the transaction commits, these pages are left on the LRU, with no
53 * ->mapping, and with attached buffers. These pages are trivially reclaimable
54 * by the VM, but their apparent absence upsets the VM accounting, and it makes
55 * the numbers in /proc/meminfo look odd.
56 *
57 * So here, we have a buffer which has just come off the forget list. Look to
58 * see if we can strip all buffers from the backing page.
59 *
60 * Called under lock_journal(), and possibly under journal_datalist_lock. The
61 * caller provided us with a ref against the buffer, and we drop that here.
62 */
63static void release_buffer_page(struct buffer_head *bh)
64{
65 struct folio *folio;
66
67 if (buffer_dirty(bh))
68 goto nope;
69 if (atomic_read(&bh->b_count) != 1)
70 goto nope;
71 folio = bh->b_folio;
72 if (folio->mapping)
73 goto nope;
74
75 /* OK, it's a truncated page */
76 if (!folio_trylock(folio))
77 goto nope;
78
79 folio_get(folio);
80 __brelse(bh);
81 try_to_free_buffers(folio);
82 folio_unlock(folio);
83 folio_put(folio);
84 return;
85
86nope:
87 __brelse(bh);
88}
89
90static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
91{
92 struct commit_header *h;
93 __u32 csum;
94
95 if (!jbd2_journal_has_csum_v2or3(j))
96 return;
97
98 h = (struct commit_header *)(bh->b_data);
99 h->h_chksum_type = 0;
100 h->h_chksum_size = 0;
101 h->h_chksum[0] = 0;
102 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, 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 commit_header *tmp;
120 struct buffer_head *bh;
121 struct timespec64 now;
122 blk_opf_t write_flags = REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS;
123
124 *cbh = NULL;
125
126 if (is_journal_aborted(journal))
127 return 0;
128
129 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
130 JBD2_COMMIT_BLOCK);
131 if (!bh)
132 return 1;
133
134 tmp = (struct commit_header *)bh->b_data;
135 ktime_get_coarse_real_ts64(&now);
136 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
137 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
138
139 if (jbd2_has_feature_checksum(journal)) {
140 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
141 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
142 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
143 }
144 jbd2_commit_block_csum_set(journal, bh);
145
146 BUFFER_TRACE(bh, "submit commit block");
147 lock_buffer(bh);
148 clear_buffer_dirty(bh);
149 set_buffer_uptodate(bh);
150 bh->b_end_io = journal_end_buffer_io_sync;
151
152 if (journal->j_flags & JBD2_BARRIER &&
153 !jbd2_has_feature_async_commit(journal))
154 write_flags |= REQ_PREFLUSH | REQ_FUA;
155
156 submit_bh(write_flags, bh);
157 *cbh = bh;
158 return 0;
159}
160
161/*
162 * This function along with journal_submit_commit_record
163 * allows to write the commit record asynchronously.
164 */
165static int journal_wait_on_commit_record(journal_t *journal,
166 struct buffer_head *bh)
167{
168 int ret = 0;
169
170 clear_buffer_dirty(bh);
171 wait_on_buffer(bh);
172
173 if (unlikely(!buffer_uptodate(bh)))
174 ret = -EIO;
175 put_bh(bh); /* One for getblk() */
176
177 return ret;
178}
179
180/* Send all the data buffers related to an inode */
181int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode)
182{
183 if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
184 return 0;
185
186 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
187 return journal->j_submit_inode_data_buffers(jinode);
188
189}
190EXPORT_SYMBOL(jbd2_submit_inode_data);
191
192int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
193{
194 if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
195 !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
196 return 0;
197 return filemap_fdatawait_range_keep_errors(
198 jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
199 jinode->i_dirty_end);
200}
201EXPORT_SYMBOL(jbd2_wait_inode_data);
202
203/*
204 * Submit all the data buffers of inode associated with the transaction to
205 * disk.
206 *
207 * We are in a committing transaction. Therefore no new inode can be added to
208 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
209 * operate on from being released while we write out pages.
210 */
211static int journal_submit_data_buffers(journal_t *journal,
212 transaction_t *commit_transaction)
213{
214 struct jbd2_inode *jinode;
215 int err, ret = 0;
216
217 spin_lock(&journal->j_list_lock);
218 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
219 if (!(jinode->i_flags & JI_WRITE_DATA))
220 continue;
221 jinode->i_flags |= JI_COMMIT_RUNNING;
222 spin_unlock(&journal->j_list_lock);
223 /* submit the inode data buffers. */
224 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
225 if (journal->j_submit_inode_data_buffers) {
226 err = journal->j_submit_inode_data_buffers(jinode);
227 if (!ret)
228 ret = err;
229 }
230 spin_lock(&journal->j_list_lock);
231 J_ASSERT(jinode->i_transaction == commit_transaction);
232 jinode->i_flags &= ~JI_COMMIT_RUNNING;
233 smp_mb();
234 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
235 }
236 spin_unlock(&journal->j_list_lock);
237 return ret;
238}
239
240int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
241{
242 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
243
244 return filemap_fdatawait_range_keep_errors(mapping,
245 jinode->i_dirty_start,
246 jinode->i_dirty_end);
247}
248
249/*
250 * Wait for data submitted for writeout, refile inodes to proper
251 * transaction if needed.
252 *
253 */
254static int journal_finish_inode_data_buffers(journal_t *journal,
255 transaction_t *commit_transaction)
256{
257 struct jbd2_inode *jinode, *next_i;
258 int err, ret = 0;
259
260 /* For locking, see the comment in journal_submit_data_buffers() */
261 spin_lock(&journal->j_list_lock);
262 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
263 if (!(jinode->i_flags & JI_WAIT_DATA))
264 continue;
265 jinode->i_flags |= JI_COMMIT_RUNNING;
266 spin_unlock(&journal->j_list_lock);
267 /* wait for the inode data buffers writeout. */
268 if (journal->j_finish_inode_data_buffers) {
269 err = journal->j_finish_inode_data_buffers(jinode);
270 if (!ret)
271 ret = err;
272 }
273 cond_resched();
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 jinode->i_dirty_start = 0;
292 jinode->i_dirty_end = 0;
293 }
294 }
295 spin_unlock(&journal->j_list_lock);
296
297 return ret;
298}
299
300static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
301{
302 char *addr;
303 __u32 checksum;
304
305 addr = kmap_local_folio(bh->b_folio, bh_offset(bh));
306 checksum = crc32_be(crc32_sum, addr, bh->b_size);
307 kunmap_local(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 __u8 *addr;
325 __u32 csum32;
326 __be32 seq;
327
328 if (!jbd2_journal_has_csum_v2or3(j))
329 return;
330
331 seq = cpu_to_be32(sequence);
332 addr = kmap_local_folio(bh->b_folio, bh_offset(bh));
333 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
334 csum32 = jbd2_chksum(j, csum32, addr, bh->b_size);
335 kunmap_local(addr);
336
337 if (jbd2_has_feature_csum3(j))
338 tag3->t_checksum = cpu_to_be32(csum32);
339 else
340 tag->t_checksum = cpu_to_be16(csum32);
341}
342/*
343 * jbd2_journal_commit_transaction
344 *
345 * The primary function for committing a transaction to the log. This
346 * function is called by the journal thread to begin a complete commit.
347 */
348void jbd2_journal_commit_transaction(journal_t *journal)
349{
350 struct transaction_stats_s stats;
351 transaction_t *commit_transaction;
352 struct journal_head *jh;
353 struct buffer_head *descriptor;
354 struct buffer_head **wbuf = journal->j_wbuf;
355 int bufs;
356 int escape;
357 int err;
358 unsigned long long blocknr;
359 ktime_t start_time;
360 u64 commit_time;
361 char *tagp = NULL;
362 journal_block_tag_t *tag = NULL;
363 int space_left = 0;
364 int first_tag = 0;
365 int tag_flag;
366 int i;
367 int tag_bytes = journal_tag_bytes(journal);
368 struct buffer_head *cbh = NULL; /* For transactional checksums */
369 __u32 crc32_sum = ~0;
370 struct blk_plug plug;
371 /* Tail of the journal */
372 unsigned long first_block;
373 tid_t first_tid;
374 int update_tail;
375 int csum_size = 0;
376 LIST_HEAD(io_bufs);
377 LIST_HEAD(log_bufs);
378
379 if (jbd2_journal_has_csum_v2or3(journal))
380 csum_size = sizeof(struct jbd2_journal_block_tail);
381
382 /*
383 * First job: lock down the current transaction and wait for
384 * all outstanding updates to complete.
385 */
386
387 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
388 if (journal->j_flags & JBD2_FLUSHED) {
389 jbd2_debug(3, "super block updated\n");
390 mutex_lock_io(&journal->j_checkpoint_mutex);
391 /*
392 * We hold j_checkpoint_mutex so tail cannot change under us.
393 * We don't need any special data guarantees for writing sb
394 * since journal is empty and it is ok for write to be
395 * flushed only with transaction commit.
396 */
397 jbd2_journal_update_sb_log_tail(journal,
398 journal->j_tail_sequence,
399 journal->j_tail, 0);
400 mutex_unlock(&journal->j_checkpoint_mutex);
401 } else {
402 jbd2_debug(3, "superblock not updated\n");
403 }
404
405 J_ASSERT(journal->j_running_transaction != NULL);
406 J_ASSERT(journal->j_committing_transaction == NULL);
407
408 write_lock(&journal->j_state_lock);
409 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
410 while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
411 DEFINE_WAIT(wait);
412
413 prepare_to_wait(&journal->j_fc_wait, &wait,
414 TASK_UNINTERRUPTIBLE);
415 write_unlock(&journal->j_state_lock);
416 schedule();
417 write_lock(&journal->j_state_lock);
418 finish_wait(&journal->j_fc_wait, &wait);
419 /*
420 * TODO: by blocking fast commits here, we are increasing
421 * fsync() latency slightly. Strictly speaking, we don't need
422 * to block fast commits until the transaction enters T_FLUSH
423 * state. So an optimization is possible where we block new fast
424 * commits here and wait for existing ones to complete
425 * just before we enter T_FLUSH. That way, the existing fast
426 * commits and this full commit can proceed parallely.
427 */
428 }
429 write_unlock(&journal->j_state_lock);
430
431 commit_transaction = journal->j_running_transaction;
432
433 trace_jbd2_start_commit(journal, commit_transaction);
434 jbd2_debug(1, "JBD2: starting commit of transaction %d\n",
435 commit_transaction->t_tid);
436
437 write_lock(&journal->j_state_lock);
438 journal->j_fc_off = 0;
439 J_ASSERT(commit_transaction->t_state == T_RUNNING);
440 commit_transaction->t_state = T_LOCKED;
441
442 trace_jbd2_commit_locking(journal, commit_transaction);
443 stats.run.rs_wait = commit_transaction->t_max_wait;
444 stats.run.rs_request_delay = 0;
445 stats.run.rs_locked = jiffies;
446 if (commit_transaction->t_requested)
447 stats.run.rs_request_delay =
448 jbd2_time_diff(commit_transaction->t_requested,
449 stats.run.rs_locked);
450 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
451 stats.run.rs_locked);
452
453 // waits for any t_updates to finish
454 jbd2_journal_wait_updates(journal);
455
456 commit_transaction->t_state = T_SWITCH;
457
458 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
459 journal->j_max_transaction_buffers);
460
461 /*
462 * First thing we are allowed to do is to discard any remaining
463 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
464 * that there are no such buffers: if a large filesystem
465 * operation like a truncate needs to split itself over multiple
466 * transactions, then it may try to do a jbd2_journal_restart() while
467 * there are still BJ_Reserved buffers outstanding. These must
468 * be released cleanly from the current transaction.
469 *
470 * In this case, the filesystem must still reserve write access
471 * again before modifying the buffer in the new transaction, but
472 * we do not require it to remember exactly which old buffers it
473 * has reserved. This is consistent with the existing behaviour
474 * that multiple jbd2_journal_get_write_access() calls to the same
475 * buffer are perfectly permissible.
476 * We use journal->j_state_lock here to serialize processing of
477 * t_reserved_list with eviction of buffers from journal_unmap_buffer().
478 */
479 while (commit_transaction->t_reserved_list) {
480 jh = commit_transaction->t_reserved_list;
481 JBUFFER_TRACE(jh, "reserved, unused: refile");
482 /*
483 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
484 * leave undo-committed data.
485 */
486 if (jh->b_committed_data) {
487 struct buffer_head *bh = jh2bh(jh);
488
489 spin_lock(&jh->b_state_lock);
490 jbd2_free(jh->b_committed_data, bh->b_size);
491 jh->b_committed_data = NULL;
492 spin_unlock(&jh->b_state_lock);
493 }
494 jbd2_journal_refile_buffer(journal, jh);
495 }
496
497 write_unlock(&journal->j_state_lock);
498 /*
499 * Now try to drop any written-back buffers from the journal's
500 * checkpoint lists. We do this *before* commit because it potentially
501 * frees some memory
502 */
503 spin_lock(&journal->j_list_lock);
504 __jbd2_journal_clean_checkpoint_list(journal, JBD2_SHRINK_BUSY_STOP);
505 spin_unlock(&journal->j_list_lock);
506
507 jbd2_debug(3, "JBD2: commit phase 1\n");
508
509 /*
510 * Clear revoked flag to reflect there is no revoked buffers
511 * in the next transaction which is going to be started.
512 */
513 jbd2_clear_buffer_revoked_flags(journal);
514
515 /*
516 * Switch to a new revoke table.
517 */
518 jbd2_journal_switch_revoke_table(journal);
519
520 write_lock(&journal->j_state_lock);
521 /*
522 * Reserved credits cannot be claimed anymore, free them
523 */
524 atomic_sub(atomic_read(&journal->j_reserved_credits),
525 &commit_transaction->t_outstanding_credits);
526
527 trace_jbd2_commit_flushing(journal, commit_transaction);
528 stats.run.rs_flushing = jiffies;
529 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
530 stats.run.rs_flushing);
531
532 commit_transaction->t_state = T_FLUSH;
533 journal->j_committing_transaction = commit_transaction;
534 journal->j_running_transaction = NULL;
535 start_time = ktime_get();
536 commit_transaction->t_log_start = journal->j_head;
537 wake_up_all(&journal->j_wait_transaction_locked);
538 write_unlock(&journal->j_state_lock);
539
540 jbd2_debug(3, "JBD2: commit phase 2a\n");
541
542 /*
543 * Now start flushing things to disk, in the order they appear
544 * on the transaction lists. Data blocks go first.
545 */
546 err = journal_submit_data_buffers(journal, commit_transaction);
547 if (err)
548 jbd2_journal_abort(journal, err);
549
550 blk_start_plug(&plug);
551 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
552
553 jbd2_debug(3, "JBD2: commit phase 2b\n");
554
555 /*
556 * Way to go: we have now written out all of the data for a
557 * transaction! Now comes the tricky part: we need to write out
558 * metadata. Loop over the transaction's entire buffer list:
559 */
560 write_lock(&journal->j_state_lock);
561 commit_transaction->t_state = T_COMMIT;
562 write_unlock(&journal->j_state_lock);
563
564 trace_jbd2_commit_logging(journal, commit_transaction);
565 stats.run.rs_logging = jiffies;
566 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
567 stats.run.rs_logging);
568 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
569 stats.run.rs_blocks_logged = 0;
570
571 J_ASSERT(commit_transaction->t_nr_buffers <=
572 atomic_read(&commit_transaction->t_outstanding_credits));
573
574 bufs = 0;
575 descriptor = NULL;
576 while (commit_transaction->t_buffers) {
577
578 /* Find the next buffer to be journaled... */
579
580 jh = commit_transaction->t_buffers;
581
582 /* If we're in abort mode, we just un-journal the buffer and
583 release it. */
584
585 if (is_journal_aborted(journal)) {
586 clear_buffer_jbddirty(jh2bh(jh));
587 JBUFFER_TRACE(jh, "journal is aborting: refile");
588 jbd2_buffer_abort_trigger(jh,
589 jh->b_frozen_data ?
590 jh->b_frozen_triggers :
591 jh->b_triggers);
592 jbd2_journal_refile_buffer(journal, jh);
593 /* If that was the last one, we need to clean up
594 * any descriptor buffers which may have been
595 * already allocated, even if we are now
596 * aborting. */
597 if (!commit_transaction->t_buffers)
598 goto start_journal_io;
599 continue;
600 }
601
602 /* Make sure we have a descriptor block in which to
603 record the metadata buffer. */
604
605 if (!descriptor) {
606 J_ASSERT (bufs == 0);
607
608 jbd2_debug(4, "JBD2: get descriptor\n");
609
610 descriptor = jbd2_journal_get_descriptor_buffer(
611 commit_transaction,
612 JBD2_DESCRIPTOR_BLOCK);
613 if (!descriptor) {
614 jbd2_journal_abort(journal, -EIO);
615 continue;
616 }
617
618 jbd2_debug(4, "JBD2: got buffer %llu (%p)\n",
619 (unsigned long long)descriptor->b_blocknr,
620 descriptor->b_data);
621 tagp = &descriptor->b_data[sizeof(journal_header_t)];
622 space_left = descriptor->b_size -
623 sizeof(journal_header_t);
624 first_tag = 1;
625 set_buffer_jwrite(descriptor);
626 set_buffer_dirty(descriptor);
627 wbuf[bufs++] = descriptor;
628
629 /* Record it so that we can wait for IO
630 completion later */
631 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
632 jbd2_file_log_bh(&log_bufs, descriptor);
633 }
634
635 /* Where is the buffer to be written? */
636
637 err = jbd2_journal_next_log_block(journal, &blocknr);
638 /* If the block mapping failed, just abandon the buffer
639 and repeat this loop: we'll fall into the
640 refile-on-abort condition above. */
641 if (err) {
642 jbd2_journal_abort(journal, err);
643 continue;
644 }
645
646 /*
647 * start_this_handle() uses t_outstanding_credits to determine
648 * the free space in the log.
649 */
650 atomic_dec(&commit_transaction->t_outstanding_credits);
651
652 /* Bump b_count to prevent truncate from stumbling over
653 the shadowed buffer! @@@ This can go if we ever get
654 rid of the shadow pairing of buffers. */
655 atomic_inc(&jh2bh(jh)->b_count);
656
657 /*
658 * Make a temporary IO buffer with which to write it out
659 * (this will requeue the metadata buffer to BJ_Shadow).
660 */
661 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
662 JBUFFER_TRACE(jh, "ph3: write metadata");
663 escape = jbd2_journal_write_metadata_buffer(commit_transaction,
664 jh, &wbuf[bufs], blocknr);
665 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
666
667 /* Record the new block's tag in the current descriptor
668 buffer */
669
670 tag_flag = 0;
671 if (escape)
672 tag_flag |= JBD2_FLAG_ESCAPE;
673 if (!first_tag)
674 tag_flag |= JBD2_FLAG_SAME_UUID;
675
676 tag = (journal_block_tag_t *) tagp;
677 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
678 tag->t_flags = cpu_to_be16(tag_flag);
679 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
680 commit_transaction->t_tid);
681 tagp += tag_bytes;
682 space_left -= tag_bytes;
683 bufs++;
684
685 if (first_tag) {
686 memcpy (tagp, journal->j_uuid, 16);
687 tagp += 16;
688 space_left -= 16;
689 first_tag = 0;
690 }
691
692 /* If there's no more to do, or if the descriptor is full,
693 let the IO rip! */
694
695 if (bufs == journal->j_wbufsize ||
696 commit_transaction->t_buffers == NULL ||
697 space_left < tag_bytes + 16 + csum_size) {
698
699 jbd2_debug(4, "JBD2: Submit %d IOs\n", bufs);
700
701 /* Write an end-of-descriptor marker before
702 submitting the IOs. "tag" still points to
703 the last tag we set up. */
704
705 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
706start_journal_io:
707 if (descriptor)
708 jbd2_descriptor_block_csum_set(journal,
709 descriptor);
710
711 for (i = 0; i < bufs; i++) {
712 struct buffer_head *bh = wbuf[i];
713
714 /*
715 * Compute checksum.
716 */
717 if (jbd2_has_feature_checksum(journal)) {
718 crc32_sum =
719 jbd2_checksum_data(crc32_sum, bh);
720 }
721
722 lock_buffer(bh);
723 clear_buffer_dirty(bh);
724 set_buffer_uptodate(bh);
725 bh->b_end_io = journal_end_buffer_io_sync;
726 submit_bh(REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS,
727 bh);
728 }
729 cond_resched();
730
731 /* Force a new descriptor to be generated next
732 time round the loop. */
733 descriptor = NULL;
734 bufs = 0;
735 }
736 }
737
738 err = journal_finish_inode_data_buffers(journal, commit_transaction);
739 if (err) {
740 printk(KERN_WARNING
741 "JBD2: Detected IO errors while flushing file data "
742 "on %s\n", journal->j_devname);
743 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
744 jbd2_journal_abort(journal, err);
745 err = 0;
746 }
747
748 /*
749 * Get current oldest transaction in the log before we issue flush
750 * to the filesystem device. After the flush we can be sure that
751 * blocks of all older transactions are checkpointed to persistent
752 * storage and we will be safe to update journal start in the
753 * superblock with the numbers we get here.
754 */
755 update_tail =
756 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
757
758 write_lock(&journal->j_state_lock);
759 if (update_tail) {
760 long freed = first_block - journal->j_tail;
761
762 if (first_block < journal->j_tail)
763 freed += journal->j_last - journal->j_first;
764 /* Update tail only if we free significant amount of space */
765 if (freed < journal->j_max_transaction_buffers)
766 update_tail = 0;
767 }
768 J_ASSERT(commit_transaction->t_state == T_COMMIT);
769 commit_transaction->t_state = T_COMMIT_DFLUSH;
770 write_unlock(&journal->j_state_lock);
771
772 /*
773 * If the journal is not located on the file system device,
774 * then we must flush the file system device before we issue
775 * the commit record and update the journal tail sequence.
776 */
777 if ((commit_transaction->t_need_data_flush || update_tail) &&
778 (journal->j_fs_dev != journal->j_dev) &&
779 (journal->j_flags & JBD2_BARRIER))
780 blkdev_issue_flush(journal->j_fs_dev);
781
782 /* Done it all: now write the commit record asynchronously. */
783 if (jbd2_has_feature_async_commit(journal)) {
784 err = journal_submit_commit_record(journal, commit_transaction,
785 &cbh, crc32_sum);
786 if (err)
787 jbd2_journal_abort(journal, err);
788 }
789
790 blk_finish_plug(&plug);
791
792 /* Lo and behold: we have just managed to send a transaction to
793 the log. Before we can commit it, wait for the IO so far to
794 complete. Control buffers being written are on the
795 transaction's t_log_list queue, and metadata buffers are on
796 the io_bufs list.
797
798 Wait for the buffers in reverse order. That way we are
799 less likely to be woken up until all IOs have completed, and
800 so we incur less scheduling load.
801 */
802
803 jbd2_debug(3, "JBD2: commit phase 3\n");
804
805 while (!list_empty(&io_bufs)) {
806 struct buffer_head *bh = list_entry(io_bufs.prev,
807 struct buffer_head,
808 b_assoc_buffers);
809
810 wait_on_buffer(bh);
811 cond_resched();
812
813 if (unlikely(!buffer_uptodate(bh)))
814 err = -EIO;
815 jbd2_unfile_log_bh(bh);
816 stats.run.rs_blocks_logged++;
817
818 /*
819 * The list contains temporary buffer heads created by
820 * jbd2_journal_write_metadata_buffer().
821 */
822 BUFFER_TRACE(bh, "dumping temporary bh");
823 __brelse(bh);
824 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
825 free_buffer_head(bh);
826
827 /* We also have to refile the corresponding shadowed buffer */
828 jh = commit_transaction->t_shadow_list->b_tprev;
829 bh = jh2bh(jh);
830 clear_buffer_jwrite(bh);
831 J_ASSERT_BH(bh, buffer_jbddirty(bh));
832 J_ASSERT_BH(bh, !buffer_shadow(bh));
833
834 /* The metadata is now released for reuse, but we need
835 to remember it against this transaction so that when
836 we finally commit, we can do any checkpointing
837 required. */
838 JBUFFER_TRACE(jh, "file as BJ_Forget");
839 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
840 JBUFFER_TRACE(jh, "brelse shadowed buffer");
841 __brelse(bh);
842 }
843
844 J_ASSERT (commit_transaction->t_shadow_list == NULL);
845
846 jbd2_debug(3, "JBD2: commit phase 4\n");
847
848 /* Here we wait for the revoke record and descriptor record buffers */
849 while (!list_empty(&log_bufs)) {
850 struct buffer_head *bh;
851
852 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
853 wait_on_buffer(bh);
854 cond_resched();
855
856 if (unlikely(!buffer_uptodate(bh)))
857 err = -EIO;
858
859 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
860 clear_buffer_jwrite(bh);
861 jbd2_unfile_log_bh(bh);
862 stats.run.rs_blocks_logged++;
863 __brelse(bh); /* One for getblk */
864 /* AKPM: bforget here */
865 }
866
867 if (err)
868 jbd2_journal_abort(journal, err);
869
870 jbd2_debug(3, "JBD2: commit phase 5\n");
871 write_lock(&journal->j_state_lock);
872 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
873 commit_transaction->t_state = T_COMMIT_JFLUSH;
874 write_unlock(&journal->j_state_lock);
875
876 if (!jbd2_has_feature_async_commit(journal)) {
877 err = journal_submit_commit_record(journal, commit_transaction,
878 &cbh, crc32_sum);
879 if (err)
880 jbd2_journal_abort(journal, err);
881 }
882 if (cbh)
883 err = journal_wait_on_commit_record(journal, cbh);
884 stats.run.rs_blocks_logged++;
885 if (jbd2_has_feature_async_commit(journal) &&
886 journal->j_flags & JBD2_BARRIER) {
887 blkdev_issue_flush(journal->j_dev);
888 }
889
890 if (err)
891 jbd2_journal_abort(journal, err);
892
893 WARN_ON_ONCE(
894 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
895
896 /*
897 * Now disk caches for filesystem device are flushed so we are safe to
898 * erase checkpointed transactions from the log by updating journal
899 * superblock.
900 */
901 if (update_tail)
902 jbd2_update_log_tail(journal, first_tid, first_block);
903
904 /* End of a transaction! Finally, we can do checkpoint
905 processing: any buffers committed as a result of this
906 transaction can be removed from any checkpoint list it was on
907 before. */
908
909 jbd2_debug(3, "JBD2: commit phase 6\n");
910
911 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
912 J_ASSERT(commit_transaction->t_buffers == NULL);
913 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
914 J_ASSERT(commit_transaction->t_shadow_list == NULL);
915
916restart_loop:
917 /*
918 * As there are other places (journal_unmap_buffer()) adding buffers
919 * to this list we have to be careful and hold the j_list_lock.
920 */
921 spin_lock(&journal->j_list_lock);
922 while (commit_transaction->t_forget) {
923 transaction_t *cp_transaction;
924 struct buffer_head *bh;
925 int try_to_free = 0;
926 bool drop_ref;
927
928 jh = commit_transaction->t_forget;
929 spin_unlock(&journal->j_list_lock);
930 bh = jh2bh(jh);
931 /*
932 * Get a reference so that bh cannot be freed before we are
933 * done with it.
934 */
935 get_bh(bh);
936 spin_lock(&jh->b_state_lock);
937 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
938
939 /*
940 * If there is undo-protected committed data against
941 * this buffer, then we can remove it now. If it is a
942 * buffer needing such protection, the old frozen_data
943 * field now points to a committed version of the
944 * buffer, so rotate that field to the new committed
945 * data.
946 *
947 * Otherwise, we can just throw away the frozen data now.
948 *
949 * We also know that the frozen data has already fired
950 * its triggers if they exist, so we can clear that too.
951 */
952 if (jh->b_committed_data) {
953 jbd2_free(jh->b_committed_data, bh->b_size);
954 jh->b_committed_data = NULL;
955 if (jh->b_frozen_data) {
956 jh->b_committed_data = jh->b_frozen_data;
957 jh->b_frozen_data = NULL;
958 jh->b_frozen_triggers = NULL;
959 }
960 } else if (jh->b_frozen_data) {
961 jbd2_free(jh->b_frozen_data, bh->b_size);
962 jh->b_frozen_data = NULL;
963 jh->b_frozen_triggers = NULL;
964 }
965
966 spin_lock(&journal->j_list_lock);
967 cp_transaction = jh->b_cp_transaction;
968 if (cp_transaction) {
969 JBUFFER_TRACE(jh, "remove from old cp transaction");
970 cp_transaction->t_chp_stats.cs_dropped++;
971 __jbd2_journal_remove_checkpoint(jh);
972 }
973
974 /* Only re-checkpoint the buffer_head if it is marked
975 * dirty. If the buffer was added to the BJ_Forget list
976 * by jbd2_journal_forget, it may no longer be dirty and
977 * there's no point in keeping a checkpoint record for
978 * it. */
979
980 /*
981 * A buffer which has been freed while still being journaled
982 * by a previous transaction, refile the buffer to BJ_Forget of
983 * the running transaction. If the just committed transaction
984 * contains "add to orphan" operation, we can completely
985 * invalidate the buffer now. We are rather through in that
986 * since the buffer may be still accessible when blocksize <
987 * pagesize and it is attached to the last partial page.
988 */
989 if (buffer_freed(bh) && !jh->b_next_transaction) {
990 struct address_space *mapping;
991
992 clear_buffer_freed(bh);
993 clear_buffer_jbddirty(bh);
994
995 /*
996 * Block device buffers need to stay mapped all the
997 * time, so it is enough to clear buffer_jbddirty and
998 * buffer_freed bits. For the file mapping buffers (i.e.
999 * journalled data) we need to unmap buffer and clear
1000 * more bits. We also need to be careful about the check
1001 * because the data page mapping can get cleared under
1002 * our hands. Note that if mapping == NULL, we don't
1003 * need to make buffer unmapped because the page is
1004 * already detached from the mapping and buffers cannot
1005 * get reused.
1006 */
1007 mapping = READ_ONCE(bh->b_folio->mapping);
1008 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1009 clear_buffer_mapped(bh);
1010 clear_buffer_new(bh);
1011 clear_buffer_req(bh);
1012 bh->b_bdev = NULL;
1013 }
1014 }
1015
1016 if (buffer_jbddirty(bh)) {
1017 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1018 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1019 if (is_journal_aborted(journal))
1020 clear_buffer_jbddirty(bh);
1021 } else {
1022 J_ASSERT_BH(bh, !buffer_dirty(bh));
1023 /*
1024 * The buffer on BJ_Forget list and not jbddirty means
1025 * it has been freed by this transaction and hence it
1026 * could not have been reallocated until this
1027 * transaction has committed. *BUT* it could be
1028 * reallocated once we have written all the data to
1029 * disk and before we process the buffer on BJ_Forget
1030 * list.
1031 */
1032 if (!jh->b_next_transaction)
1033 try_to_free = 1;
1034 }
1035 JBUFFER_TRACE(jh, "refile or unfile buffer");
1036 drop_ref = __jbd2_journal_refile_buffer(jh);
1037 spin_unlock(&jh->b_state_lock);
1038 if (drop_ref)
1039 jbd2_journal_put_journal_head(jh);
1040 if (try_to_free)
1041 release_buffer_page(bh); /* Drops bh reference */
1042 else
1043 __brelse(bh);
1044 cond_resched_lock(&journal->j_list_lock);
1045 }
1046 spin_unlock(&journal->j_list_lock);
1047 /*
1048 * This is a bit sleazy. We use j_list_lock to protect transition
1049 * of a transaction into T_FINISHED state and calling
1050 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1051 * other checkpointing code processing the transaction...
1052 */
1053 write_lock(&journal->j_state_lock);
1054 spin_lock(&journal->j_list_lock);
1055 /*
1056 * Now recheck if some buffers did not get attached to the transaction
1057 * while the lock was dropped...
1058 */
1059 if (commit_transaction->t_forget) {
1060 spin_unlock(&journal->j_list_lock);
1061 write_unlock(&journal->j_state_lock);
1062 goto restart_loop;
1063 }
1064
1065 /* Add the transaction to the checkpoint list
1066 * __journal_remove_checkpoint() can not destroy transaction
1067 * under us because it is not marked as T_FINISHED yet */
1068 if (journal->j_checkpoint_transactions == NULL) {
1069 journal->j_checkpoint_transactions = commit_transaction;
1070 commit_transaction->t_cpnext = commit_transaction;
1071 commit_transaction->t_cpprev = commit_transaction;
1072 } else {
1073 commit_transaction->t_cpnext =
1074 journal->j_checkpoint_transactions;
1075 commit_transaction->t_cpprev =
1076 commit_transaction->t_cpnext->t_cpprev;
1077 commit_transaction->t_cpnext->t_cpprev =
1078 commit_transaction;
1079 commit_transaction->t_cpprev->t_cpnext =
1080 commit_transaction;
1081 }
1082 spin_unlock(&journal->j_list_lock);
1083
1084 /* Done with this transaction! */
1085
1086 jbd2_debug(3, "JBD2: commit phase 7\n");
1087
1088 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1089
1090 commit_transaction->t_start = jiffies;
1091 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1092 commit_transaction->t_start);
1093
1094 /*
1095 * File the transaction statistics
1096 */
1097 stats.ts_tid = commit_transaction->t_tid;
1098 stats.run.rs_handle_count =
1099 atomic_read(&commit_transaction->t_handle_count);
1100 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1101 commit_transaction->t_tid, &stats.run);
1102 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1103
1104 commit_transaction->t_state = T_COMMIT_CALLBACK;
1105 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1106 WRITE_ONCE(journal->j_commit_sequence, commit_transaction->t_tid);
1107 journal->j_committing_transaction = NULL;
1108 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1109
1110 /*
1111 * weight the commit time higher than the average time so we don't
1112 * react too strongly to vast changes in the commit time
1113 */
1114 if (likely(journal->j_average_commit_time))
1115 journal->j_average_commit_time = (commit_time +
1116 journal->j_average_commit_time*3) / 4;
1117 else
1118 journal->j_average_commit_time = commit_time;
1119
1120 write_unlock(&journal->j_state_lock);
1121
1122 if (journal->j_commit_callback)
1123 journal->j_commit_callback(journal, commit_transaction);
1124 if (journal->j_fc_cleanup_callback)
1125 journal->j_fc_cleanup_callback(journal, 1, commit_transaction->t_tid);
1126
1127 trace_jbd2_end_commit(journal, commit_transaction);
1128 jbd2_debug(1, "JBD2: commit %d complete, head %d\n",
1129 journal->j_commit_sequence, journal->j_tail_sequence);
1130
1131 write_lock(&journal->j_state_lock);
1132 journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1133 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1134 spin_lock(&journal->j_list_lock);
1135 commit_transaction->t_state = T_FINISHED;
1136 /* Check if the transaction can be dropped now that we are finished */
1137 if (commit_transaction->t_checkpoint_list == NULL) {
1138 __jbd2_journal_drop_transaction(journal, commit_transaction);
1139 jbd2_journal_free_transaction(commit_transaction);
1140 }
1141 spin_unlock(&journal->j_list_lock);
1142 write_unlock(&journal->j_state_lock);
1143 wake_up(&journal->j_wait_done_commit);
1144 wake_up(&journal->j_fc_wait);
1145
1146 /*
1147 * Calculate overall stats
1148 */
1149 spin_lock(&journal->j_history_lock);
1150 journal->j_stats.ts_tid++;
1151 journal->j_stats.ts_requested += stats.ts_requested;
1152 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1153 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1154 journal->j_stats.run.rs_running += stats.run.rs_running;
1155 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1156 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1157 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1158 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1159 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1160 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1161 spin_unlock(&journal->j_history_lock);
1162}