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1/*
2 * linux/fs/jbd2/commit.c
3 *
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
5 *
6 * Copyright 1998 Red Hat corp --- All Rights Reserved
7 *
8 * This file is part of the Linux kernel and is made available under
9 * the terms of the GNU General Public License, version 2, or at your
10 * option, any later version, incorporated herein by reference.
11 *
12 * Journal commit routines for the generic filesystem journaling code;
13 * part of the ext2fs journaling system.
14 */
15
16#include <linux/time.h>
17#include <linux/fs.h>
18#include <linux/jbd2.h>
19#include <linux/errno.h>
20#include <linux/slab.h>
21#include <linux/mm.h>
22#include <linux/pagemap.h>
23#include <linux/jiffies.h>
24#include <linux/crc32.h>
25#include <linux/writeback.h>
26#include <linux/backing-dev.h>
27#include <linux/bio.h>
28#include <linux/blkdev.h>
29#include <linux/bitops.h>
30#include <trace/events/jbd2.h>
31
32/*
33 * IO end handler for temporary buffer_heads handling writes to the journal.
34 */
35static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
36{
37 struct buffer_head *orig_bh = bh->b_private;
38
39 BUFFER_TRACE(bh, "");
40 if (uptodate)
41 set_buffer_uptodate(bh);
42 else
43 clear_buffer_uptodate(bh);
44 if (orig_bh) {
45 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
46 smp_mb__after_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 page *page;
66
67 if (buffer_dirty(bh))
68 goto nope;
69 if (atomic_read(&bh->b_count) != 1)
70 goto nope;
71 page = bh->b_page;
72 if (!page)
73 goto nope;
74 if (page->mapping)
75 goto nope;
76
77 /* OK, it's a truncated page */
78 if (!trylock_page(page))
79 goto nope;
80
81 get_page(page);
82 __brelse(bh);
83 try_to_free_buffers(page);
84 unlock_page(page);
85 put_page(page);
86 return;
87
88nope:
89 __brelse(bh);
90}
91
92static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
93{
94 struct commit_header *h;
95 __u32 csum;
96
97 if (!jbd2_journal_has_csum_v2or3(j))
98 return;
99
100 h = (struct commit_header *)(bh->b_data);
101 h->h_chksum_type = 0;
102 h->h_chksum_size = 0;
103 h->h_chksum[0] = 0;
104 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
105 h->h_chksum[0] = cpu_to_be32(csum);
106}
107
108/*
109 * Done it all: now submit the commit record. We should have
110 * cleaned up our previous buffers by now, so if we are in abort
111 * mode we can now just skip the rest of the journal write
112 * entirely.
113 *
114 * Returns 1 if the journal needs to be aborted or 0 on success
115 */
116static int journal_submit_commit_record(journal_t *journal,
117 transaction_t *commit_transaction,
118 struct buffer_head **cbh,
119 __u32 crc32_sum)
120{
121 struct commit_header *tmp;
122 struct buffer_head *bh;
123 int ret;
124 struct timespec64 now;
125
126 *cbh = NULL;
127
128 if (is_journal_aborted(journal))
129 return 0;
130
131 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
132 JBD2_COMMIT_BLOCK);
133 if (!bh)
134 return 1;
135
136 tmp = (struct commit_header *)bh->b_data;
137 ktime_get_coarse_real_ts64(&now);
138 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
139 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
140
141 if (jbd2_has_feature_checksum(journal)) {
142 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
143 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
144 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
145 }
146 jbd2_commit_block_csum_set(journal, bh);
147
148 BUFFER_TRACE(bh, "submit commit block");
149 lock_buffer(bh);
150 clear_buffer_dirty(bh);
151 set_buffer_uptodate(bh);
152 bh->b_end_io = journal_end_buffer_io_sync;
153
154 if (journal->j_flags & JBD2_BARRIER &&
155 !jbd2_has_feature_async_commit(journal))
156 ret = submit_bh(REQ_OP_WRITE,
157 REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh);
158 else
159 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
160
161 *cbh = bh;
162 return ret;
163}
164
165/*
166 * This function along with journal_submit_commit_record
167 * allows to write the commit record asynchronously.
168 */
169static int journal_wait_on_commit_record(journal_t *journal,
170 struct buffer_head *bh)
171{
172 int ret = 0;
173
174 clear_buffer_dirty(bh);
175 wait_on_buffer(bh);
176
177 if (unlikely(!buffer_uptodate(bh)))
178 ret = -EIO;
179 put_bh(bh); /* One for getblk() */
180
181 return ret;
182}
183
184/*
185 * write the filemap data using writepage() address_space_operations.
186 * We don't do block allocation here even for delalloc. We don't
187 * use writepages() because with delayed allocation we may be doing
188 * block allocation in writepages().
189 */
190static int journal_submit_inode_data_buffers(struct address_space *mapping,
191 loff_t dirty_start, loff_t dirty_end)
192{
193 int ret;
194 struct writeback_control wbc = {
195 .sync_mode = WB_SYNC_ALL,
196 .nr_to_write = mapping->nrpages * 2,
197 .range_start = dirty_start,
198 .range_end = dirty_end,
199 };
200
201 ret = generic_writepages(mapping, &wbc);
202 return ret;
203}
204
205/*
206 * Submit all the data buffers of inode associated with the transaction to
207 * disk.
208 *
209 * We are in a committing transaction. Therefore no new inode can be added to
210 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
211 * operate on from being released while we write out pages.
212 */
213static int journal_submit_data_buffers(journal_t *journal,
214 transaction_t *commit_transaction)
215{
216 struct jbd2_inode *jinode;
217 int err, ret = 0;
218 struct address_space *mapping;
219
220 spin_lock(&journal->j_list_lock);
221 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
222 loff_t dirty_start = jinode->i_dirty_start;
223 loff_t dirty_end = jinode->i_dirty_end;
224
225 if (!(jinode->i_flags & JI_WRITE_DATA))
226 continue;
227 mapping = jinode->i_vfs_inode->i_mapping;
228 jinode->i_flags |= JI_COMMIT_RUNNING;
229 spin_unlock(&journal->j_list_lock);
230 /*
231 * submit the inode data buffers. We use writepage
232 * instead of writepages. Because writepages can do
233 * block allocation with delalloc. We need to write
234 * only allocated blocks here.
235 */
236 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
237 err = journal_submit_inode_data_buffers(mapping, dirty_start,
238 dirty_end);
239 if (!ret)
240 ret = err;
241 spin_lock(&journal->j_list_lock);
242 J_ASSERT(jinode->i_transaction == commit_transaction);
243 jinode->i_flags &= ~JI_COMMIT_RUNNING;
244 smp_mb();
245 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
246 }
247 spin_unlock(&journal->j_list_lock);
248 return ret;
249}
250
251/*
252 * Wait for data submitted for writeout, refile inodes to proper
253 * transaction if needed.
254 *
255 */
256static int journal_finish_inode_data_buffers(journal_t *journal,
257 transaction_t *commit_transaction)
258{
259 struct jbd2_inode *jinode, *next_i;
260 int err, ret = 0;
261
262 /* For locking, see the comment in journal_submit_data_buffers() */
263 spin_lock(&journal->j_list_lock);
264 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
265 loff_t dirty_start = jinode->i_dirty_start;
266 loff_t dirty_end = jinode->i_dirty_end;
267
268 if (!(jinode->i_flags & JI_WAIT_DATA))
269 continue;
270 jinode->i_flags |= JI_COMMIT_RUNNING;
271 spin_unlock(&journal->j_list_lock);
272 err = filemap_fdatawait_range_keep_errors(
273 jinode->i_vfs_inode->i_mapping, dirty_start,
274 dirty_end);
275 if (!ret)
276 ret = err;
277 spin_lock(&journal->j_list_lock);
278 jinode->i_flags &= ~JI_COMMIT_RUNNING;
279 smp_mb();
280 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
281 }
282
283 /* Now refile inode to proper lists */
284 list_for_each_entry_safe(jinode, next_i,
285 &commit_transaction->t_inode_list, i_list) {
286 list_del(&jinode->i_list);
287 if (jinode->i_next_transaction) {
288 jinode->i_transaction = jinode->i_next_transaction;
289 jinode->i_next_transaction = NULL;
290 list_add(&jinode->i_list,
291 &jinode->i_transaction->t_inode_list);
292 } else {
293 jinode->i_transaction = NULL;
294 jinode->i_dirty_start = 0;
295 jinode->i_dirty_end = 0;
296 }
297 }
298 spin_unlock(&journal->j_list_lock);
299
300 return ret;
301}
302
303static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
304{
305 struct page *page = bh->b_page;
306 char *addr;
307 __u32 checksum;
308
309 addr = kmap_atomic(page);
310 checksum = crc32_be(crc32_sum,
311 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
312 kunmap_atomic(addr);
313
314 return checksum;
315}
316
317static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
318 unsigned long long block)
319{
320 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
321 if (jbd2_has_feature_64bit(j))
322 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
323}
324
325static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
326 struct buffer_head *bh, __u32 sequence)
327{
328 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
329 struct page *page = bh->b_page;
330 __u8 *addr;
331 __u32 csum32;
332 __be32 seq;
333
334 if (!jbd2_journal_has_csum_v2or3(j))
335 return;
336
337 seq = cpu_to_be32(sequence);
338 addr = kmap_atomic(page);
339 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
340 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
341 bh->b_size);
342 kunmap_atomic(addr);
343
344 if (jbd2_has_feature_csum3(j))
345 tag3->t_checksum = cpu_to_be32(csum32);
346 else
347 tag->t_checksum = cpu_to_be16(csum32);
348}
349/*
350 * jbd2_journal_commit_transaction
351 *
352 * The primary function for committing a transaction to the log. This
353 * function is called by the journal thread to begin a complete commit.
354 */
355void jbd2_journal_commit_transaction(journal_t *journal)
356{
357 struct transaction_stats_s stats;
358 transaction_t *commit_transaction;
359 struct journal_head *jh;
360 struct buffer_head *descriptor;
361 struct buffer_head **wbuf = journal->j_wbuf;
362 int bufs;
363 int flags;
364 int err;
365 unsigned long long blocknr;
366 ktime_t start_time;
367 u64 commit_time;
368 char *tagp = NULL;
369 journal_block_tag_t *tag = NULL;
370 int space_left = 0;
371 int first_tag = 0;
372 int tag_flag;
373 int i;
374 int tag_bytes = journal_tag_bytes(journal);
375 struct buffer_head *cbh = NULL; /* For transactional checksums */
376 __u32 crc32_sum = ~0;
377 struct blk_plug plug;
378 /* Tail of the journal */
379 unsigned long first_block;
380 tid_t first_tid;
381 int update_tail;
382 int csum_size = 0;
383 LIST_HEAD(io_bufs);
384 LIST_HEAD(log_bufs);
385
386 if (jbd2_journal_has_csum_v2or3(journal))
387 csum_size = sizeof(struct jbd2_journal_block_tail);
388
389 /*
390 * First job: lock down the current transaction and wait for
391 * all outstanding updates to complete.
392 */
393
394 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
395 if (journal->j_flags & JBD2_FLUSHED) {
396 jbd_debug(3, "super block updated\n");
397 mutex_lock_io(&journal->j_checkpoint_mutex);
398 /*
399 * We hold j_checkpoint_mutex so tail cannot change under us.
400 * We don't need any special data guarantees for writing sb
401 * since journal is empty and it is ok for write to be
402 * flushed only with transaction commit.
403 */
404 jbd2_journal_update_sb_log_tail(journal,
405 journal->j_tail_sequence,
406 journal->j_tail,
407 REQ_SYNC);
408 mutex_unlock(&journal->j_checkpoint_mutex);
409 } else {
410 jbd_debug(3, "superblock not updated\n");
411 }
412
413 J_ASSERT(journal->j_running_transaction != NULL);
414 J_ASSERT(journal->j_committing_transaction == NULL);
415
416 commit_transaction = journal->j_running_transaction;
417
418 trace_jbd2_start_commit(journal, commit_transaction);
419 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
420 commit_transaction->t_tid);
421
422 write_lock(&journal->j_state_lock);
423 J_ASSERT(commit_transaction->t_state == T_RUNNING);
424 commit_transaction->t_state = T_LOCKED;
425
426 trace_jbd2_commit_locking(journal, commit_transaction);
427 stats.run.rs_wait = commit_transaction->t_max_wait;
428 stats.run.rs_request_delay = 0;
429 stats.run.rs_locked = jiffies;
430 if (commit_transaction->t_requested)
431 stats.run.rs_request_delay =
432 jbd2_time_diff(commit_transaction->t_requested,
433 stats.run.rs_locked);
434 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
435 stats.run.rs_locked);
436
437 spin_lock(&commit_transaction->t_handle_lock);
438 while (atomic_read(&commit_transaction->t_updates)) {
439 DEFINE_WAIT(wait);
440
441 prepare_to_wait(&journal->j_wait_updates, &wait,
442 TASK_UNINTERRUPTIBLE);
443 if (atomic_read(&commit_transaction->t_updates)) {
444 spin_unlock(&commit_transaction->t_handle_lock);
445 write_unlock(&journal->j_state_lock);
446 schedule();
447 write_lock(&journal->j_state_lock);
448 spin_lock(&commit_transaction->t_handle_lock);
449 }
450 finish_wait(&journal->j_wait_updates, &wait);
451 }
452 spin_unlock(&commit_transaction->t_handle_lock);
453 commit_transaction->t_state = T_SWITCH;
454 write_unlock(&journal->j_state_lock);
455
456 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
457 journal->j_max_transaction_buffers);
458
459 /*
460 * First thing we are allowed to do is to discard any remaining
461 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
462 * that there are no such buffers: if a large filesystem
463 * operation like a truncate needs to split itself over multiple
464 * transactions, then it may try to do a jbd2_journal_restart() while
465 * there are still BJ_Reserved buffers outstanding. These must
466 * be released cleanly from the current transaction.
467 *
468 * In this case, the filesystem must still reserve write access
469 * again before modifying the buffer in the new transaction, but
470 * we do not require it to remember exactly which old buffers it
471 * has reserved. This is consistent with the existing behaviour
472 * that multiple jbd2_journal_get_write_access() calls to the same
473 * buffer are perfectly permissible.
474 */
475 while (commit_transaction->t_reserved_list) {
476 jh = commit_transaction->t_reserved_list;
477 JBUFFER_TRACE(jh, "reserved, unused: refile");
478 /*
479 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
480 * leave undo-committed data.
481 */
482 if (jh->b_committed_data) {
483 struct buffer_head *bh = jh2bh(jh);
484
485 jbd_lock_bh_state(bh);
486 jbd2_free(jh->b_committed_data, bh->b_size);
487 jh->b_committed_data = NULL;
488 jbd_unlock_bh_state(bh);
489 }
490 jbd2_journal_refile_buffer(journal, jh);
491 }
492
493 /*
494 * Now try to drop any written-back buffers from the journal's
495 * checkpoint lists. We do this *before* commit because it potentially
496 * frees some memory
497 */
498 spin_lock(&journal->j_list_lock);
499 __jbd2_journal_clean_checkpoint_list(journal, false);
500 spin_unlock(&journal->j_list_lock);
501
502 jbd_debug(3, "JBD2: commit phase 1\n");
503
504 /*
505 * Clear revoked flag to reflect there is no revoked buffers
506 * in the next transaction which is going to be started.
507 */
508 jbd2_clear_buffer_revoked_flags(journal);
509
510 /*
511 * Switch to a new revoke table.
512 */
513 jbd2_journal_switch_revoke_table(journal);
514
515 /*
516 * Reserved credits cannot be claimed anymore, free them
517 */
518 atomic_sub(atomic_read(&journal->j_reserved_credits),
519 &commit_transaction->t_outstanding_credits);
520
521 write_lock(&journal->j_state_lock);
522 trace_jbd2_commit_flushing(journal, commit_transaction);
523 stats.run.rs_flushing = jiffies;
524 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
525 stats.run.rs_flushing);
526
527 commit_transaction->t_state = T_FLUSH;
528 journal->j_committing_transaction = commit_transaction;
529 journal->j_running_transaction = NULL;
530 start_time = ktime_get();
531 commit_transaction->t_log_start = journal->j_head;
532 wake_up(&journal->j_wait_transaction_locked);
533 write_unlock(&journal->j_state_lock);
534
535 jbd_debug(3, "JBD2: commit phase 2a\n");
536
537 /*
538 * Now start flushing things to disk, in the order they appear
539 * on the transaction lists. Data blocks go first.
540 */
541 err = journal_submit_data_buffers(journal, commit_transaction);
542 if (err)
543 jbd2_journal_abort(journal, err);
544
545 blk_start_plug(&plug);
546 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
547
548 jbd_debug(3, "JBD2: commit phase 2b\n");
549
550 /*
551 * Way to go: we have now written out all of the data for a
552 * transaction! Now comes the tricky part: we need to write out
553 * metadata. Loop over the transaction's entire buffer list:
554 */
555 write_lock(&journal->j_state_lock);
556 commit_transaction->t_state = T_COMMIT;
557 write_unlock(&journal->j_state_lock);
558
559 trace_jbd2_commit_logging(journal, commit_transaction);
560 stats.run.rs_logging = jiffies;
561 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
562 stats.run.rs_logging);
563 stats.run.rs_blocks =
564 atomic_read(&commit_transaction->t_outstanding_credits);
565 stats.run.rs_blocks_logged = 0;
566
567 J_ASSERT(commit_transaction->t_nr_buffers <=
568 atomic_read(&commit_transaction->t_outstanding_credits));
569
570 err = 0;
571 bufs = 0;
572 descriptor = NULL;
573 while (commit_transaction->t_buffers) {
574
575 /* Find the next buffer to be journaled... */
576
577 jh = commit_transaction->t_buffers;
578
579 /* If we're in abort mode, we just un-journal the buffer and
580 release it. */
581
582 if (is_journal_aborted(journal)) {
583 clear_buffer_jbddirty(jh2bh(jh));
584 JBUFFER_TRACE(jh, "journal is aborting: refile");
585 jbd2_buffer_abort_trigger(jh,
586 jh->b_frozen_data ?
587 jh->b_frozen_triggers :
588 jh->b_triggers);
589 jbd2_journal_refile_buffer(journal, jh);
590 /* If that was the last one, we need to clean up
591 * any descriptor buffers which may have been
592 * already allocated, even if we are now
593 * aborting. */
594 if (!commit_transaction->t_buffers)
595 goto start_journal_io;
596 continue;
597 }
598
599 /* Make sure we have a descriptor block in which to
600 record the metadata buffer. */
601
602 if (!descriptor) {
603 J_ASSERT (bufs == 0);
604
605 jbd_debug(4, "JBD2: get descriptor\n");
606
607 descriptor = jbd2_journal_get_descriptor_buffer(
608 commit_transaction,
609 JBD2_DESCRIPTOR_BLOCK);
610 if (!descriptor) {
611 jbd2_journal_abort(journal, -EIO);
612 continue;
613 }
614
615 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
616 (unsigned long long)descriptor->b_blocknr,
617 descriptor->b_data);
618 tagp = &descriptor->b_data[sizeof(journal_header_t)];
619 space_left = descriptor->b_size -
620 sizeof(journal_header_t);
621 first_tag = 1;
622 set_buffer_jwrite(descriptor);
623 set_buffer_dirty(descriptor);
624 wbuf[bufs++] = descriptor;
625
626 /* Record it so that we can wait for IO
627 completion later */
628 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
629 jbd2_file_log_bh(&log_bufs, descriptor);
630 }
631
632 /* Where is the buffer to be written? */
633
634 err = jbd2_journal_next_log_block(journal, &blocknr);
635 /* If the block mapping failed, just abandon the buffer
636 and repeat this loop: we'll fall into the
637 refile-on-abort condition above. */
638 if (err) {
639 jbd2_journal_abort(journal, err);
640 continue;
641 }
642
643 /*
644 * start_this_handle() uses t_outstanding_credits to determine
645 * the free space in the log, but this counter is changed
646 * by jbd2_journal_next_log_block() also.
647 */
648 atomic_dec(&commit_transaction->t_outstanding_credits);
649
650 /* Bump b_count to prevent truncate from stumbling over
651 the shadowed buffer! @@@ This can go if we ever get
652 rid of the shadow pairing of buffers. */
653 atomic_inc(&jh2bh(jh)->b_count);
654
655 /*
656 * Make a temporary IO buffer with which to write it out
657 * (this will requeue the metadata buffer to BJ_Shadow).
658 */
659 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
660 JBUFFER_TRACE(jh, "ph3: write metadata");
661 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
662 jh, &wbuf[bufs], blocknr);
663 if (flags < 0) {
664 jbd2_journal_abort(journal, flags);
665 continue;
666 }
667 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
668
669 /* Record the new block's tag in the current descriptor
670 buffer */
671
672 tag_flag = 0;
673 if (flags & 1)
674 tag_flag |= JBD2_FLAG_ESCAPE;
675 if (!first_tag)
676 tag_flag |= JBD2_FLAG_SAME_UUID;
677
678 tag = (journal_block_tag_t *) tagp;
679 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
680 tag->t_flags = cpu_to_be16(tag_flag);
681 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
682 commit_transaction->t_tid);
683 tagp += tag_bytes;
684 space_left -= tag_bytes;
685 bufs++;
686
687 if (first_tag) {
688 memcpy (tagp, journal->j_uuid, 16);
689 tagp += 16;
690 space_left -= 16;
691 first_tag = 0;
692 }
693
694 /* If there's no more to do, or if the descriptor is full,
695 let the IO rip! */
696
697 if (bufs == journal->j_wbufsize ||
698 commit_transaction->t_buffers == NULL ||
699 space_left < tag_bytes + 16 + csum_size) {
700
701 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
702
703 /* Write an end-of-descriptor marker before
704 submitting the IOs. "tag" still points to
705 the last tag we set up. */
706
707 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
708start_journal_io:
709 if (descriptor)
710 jbd2_descriptor_block_csum_set(journal,
711 descriptor);
712
713 for (i = 0; i < bufs; i++) {
714 struct buffer_head *bh = wbuf[i];
715 /*
716 * Compute checksum.
717 */
718 if (jbd2_has_feature_checksum(journal)) {
719 crc32_sum =
720 jbd2_checksum_data(crc32_sum, bh);
721 }
722
723 lock_buffer(bh);
724 clear_buffer_dirty(bh);
725 set_buffer_uptodate(bh);
726 bh->b_end_io = journal_end_buffer_io_sync;
727 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
728 }
729 cond_resched();
730 stats.run.rs_blocks_logged += bufs;
731
732 /* Force a new descriptor to be generated next
733 time round the loop. */
734 descriptor = NULL;
735 bufs = 0;
736 }
737 }
738
739 err = journal_finish_inode_data_buffers(journal, commit_transaction);
740 if (err) {
741 printk(KERN_WARNING
742 "JBD2: Detected IO errors while flushing file data "
743 "on %s\n", journal->j_devname);
744 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
745 jbd2_journal_abort(journal, err);
746 err = 0;
747 }
748
749 /*
750 * Get current oldest transaction in the log before we issue flush
751 * to the filesystem device. After the flush we can be sure that
752 * blocks of all older transactions are checkpointed to persistent
753 * storage and we will be safe to update journal start in the
754 * superblock with the numbers we get here.
755 */
756 update_tail =
757 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
758
759 write_lock(&journal->j_state_lock);
760 if (update_tail) {
761 long freed = first_block - journal->j_tail;
762
763 if (first_block < journal->j_tail)
764 freed += journal->j_last - journal->j_first;
765 /* Update tail only if we free significant amount of space */
766 if (freed < journal->j_maxlen / 4)
767 update_tail = 0;
768 }
769 J_ASSERT(commit_transaction->t_state == T_COMMIT);
770 commit_transaction->t_state = T_COMMIT_DFLUSH;
771 write_unlock(&journal->j_state_lock);
772
773 /*
774 * If the journal is not located on the file system device,
775 * then we must flush the file system device before we issue
776 * the commit record
777 */
778 if (commit_transaction->t_need_data_flush &&
779 (journal->j_fs_dev != journal->j_dev) &&
780 (journal->j_flags & JBD2_BARRIER))
781 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
782
783 /* Done it all: now write the commit record asynchronously. */
784 if (jbd2_has_feature_async_commit(journal)) {
785 err = journal_submit_commit_record(journal, commit_transaction,
786 &cbh, crc32_sum);
787 if (err)
788 __jbd2_journal_abort_hard(journal);
789 }
790
791 blk_finish_plug(&plug);
792
793 /* Lo and behold: we have just managed to send a transaction to
794 the log. Before we can commit it, wait for the IO so far to
795 complete. Control buffers being written are on the
796 transaction's t_log_list queue, and metadata buffers are on
797 the io_bufs list.
798
799 Wait for the buffers in reverse order. That way we are
800 less likely to be woken up until all IOs have completed, and
801 so we incur less scheduling load.
802 */
803
804 jbd_debug(3, "JBD2: commit phase 3\n");
805
806 while (!list_empty(&io_bufs)) {
807 struct buffer_head *bh = list_entry(io_bufs.prev,
808 struct buffer_head,
809 b_assoc_buffers);
810
811 wait_on_buffer(bh);
812 cond_resched();
813
814 if (unlikely(!buffer_uptodate(bh)))
815 err = -EIO;
816 jbd2_unfile_log_bh(bh);
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 jbd_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 __brelse(bh); /* One for getblk */
863 /* AKPM: bforget here */
864 }
865
866 if (err)
867 jbd2_journal_abort(journal, err);
868
869 jbd_debug(3, "JBD2: commit phase 5\n");
870 write_lock(&journal->j_state_lock);
871 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
872 commit_transaction->t_state = T_COMMIT_JFLUSH;
873 write_unlock(&journal->j_state_lock);
874
875 if (!jbd2_has_feature_async_commit(journal)) {
876 err = journal_submit_commit_record(journal, commit_transaction,
877 &cbh, crc32_sum);
878 if (err)
879 __jbd2_journal_abort_hard(journal);
880 }
881 if (cbh)
882 err = journal_wait_on_commit_record(journal, cbh);
883 if (jbd2_has_feature_async_commit(journal) &&
884 journal->j_flags & JBD2_BARRIER) {
885 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
886 }
887
888 if (err)
889 jbd2_journal_abort(journal, err);
890
891 /*
892 * Now disk caches for filesystem device are flushed so we are safe to
893 * erase checkpointed transactions from the log by updating journal
894 * superblock.
895 */
896 if (update_tail)
897 jbd2_update_log_tail(journal, first_tid, first_block);
898
899 /* End of a transaction! Finally, we can do checkpoint
900 processing: any buffers committed as a result of this
901 transaction can be removed from any checkpoint list it was on
902 before. */
903
904 jbd_debug(3, "JBD2: commit phase 6\n");
905
906 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
907 J_ASSERT(commit_transaction->t_buffers == NULL);
908 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
909 J_ASSERT(commit_transaction->t_shadow_list == NULL);
910
911restart_loop:
912 /*
913 * As there are other places (journal_unmap_buffer()) adding buffers
914 * to this list we have to be careful and hold the j_list_lock.
915 */
916 spin_lock(&journal->j_list_lock);
917 while (commit_transaction->t_forget) {
918 transaction_t *cp_transaction;
919 struct buffer_head *bh;
920 int try_to_free = 0;
921
922 jh = commit_transaction->t_forget;
923 spin_unlock(&journal->j_list_lock);
924 bh = jh2bh(jh);
925 /*
926 * Get a reference so that bh cannot be freed before we are
927 * done with it.
928 */
929 get_bh(bh);
930 jbd_lock_bh_state(bh);
931 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
932
933 /*
934 * If there is undo-protected committed data against
935 * this buffer, then we can remove it now. If it is a
936 * buffer needing such protection, the old frozen_data
937 * field now points to a committed version of the
938 * buffer, so rotate that field to the new committed
939 * data.
940 *
941 * Otherwise, we can just throw away the frozen data now.
942 *
943 * We also know that the frozen data has already fired
944 * its triggers if they exist, so we can clear that too.
945 */
946 if (jh->b_committed_data) {
947 jbd2_free(jh->b_committed_data, bh->b_size);
948 jh->b_committed_data = NULL;
949 if (jh->b_frozen_data) {
950 jh->b_committed_data = jh->b_frozen_data;
951 jh->b_frozen_data = NULL;
952 jh->b_frozen_triggers = NULL;
953 }
954 } else if (jh->b_frozen_data) {
955 jbd2_free(jh->b_frozen_data, bh->b_size);
956 jh->b_frozen_data = NULL;
957 jh->b_frozen_triggers = NULL;
958 }
959
960 spin_lock(&journal->j_list_lock);
961 cp_transaction = jh->b_cp_transaction;
962 if (cp_transaction) {
963 JBUFFER_TRACE(jh, "remove from old cp transaction");
964 cp_transaction->t_chp_stats.cs_dropped++;
965 __jbd2_journal_remove_checkpoint(jh);
966 }
967
968 /* Only re-checkpoint the buffer_head if it is marked
969 * dirty. If the buffer was added to the BJ_Forget list
970 * by jbd2_journal_forget, it may no longer be dirty and
971 * there's no point in keeping a checkpoint record for
972 * it. */
973
974 /*
975 * A buffer which has been freed while still being journaled by
976 * a previous transaction.
977 */
978 if (buffer_freed(bh)) {
979 /*
980 * If the running transaction is the one containing
981 * "add to orphan" operation (b_next_transaction !=
982 * NULL), we have to wait for that transaction to
983 * commit before we can really get rid of the buffer.
984 * So just clear b_modified to not confuse transaction
985 * credit accounting and refile the buffer to
986 * BJ_Forget of the running transaction. If the just
987 * committed transaction contains "add to orphan"
988 * operation, we can completely invalidate the buffer
989 * now. We are rather through in that since the
990 * buffer may be still accessible when blocksize <
991 * pagesize and it is attached to the last partial
992 * page.
993 */
994 jh->b_modified = 0;
995 if (!jh->b_next_transaction) {
996 clear_buffer_freed(bh);
997 clear_buffer_jbddirty(bh);
998 clear_buffer_mapped(bh);
999 clear_buffer_new(bh);
1000 clear_buffer_req(bh);
1001 bh->b_bdev = NULL;
1002 }
1003 }
1004
1005 if (buffer_jbddirty(bh)) {
1006 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1007 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1008 if (is_journal_aborted(journal))
1009 clear_buffer_jbddirty(bh);
1010 } else {
1011 J_ASSERT_BH(bh, !buffer_dirty(bh));
1012 /*
1013 * The buffer on BJ_Forget list and not jbddirty means
1014 * it has been freed by this transaction and hence it
1015 * could not have been reallocated until this
1016 * transaction has committed. *BUT* it could be
1017 * reallocated once we have written all the data to
1018 * disk and before we process the buffer on BJ_Forget
1019 * list.
1020 */
1021 if (!jh->b_next_transaction)
1022 try_to_free = 1;
1023 }
1024 JBUFFER_TRACE(jh, "refile or unfile buffer");
1025 __jbd2_journal_refile_buffer(jh);
1026 jbd_unlock_bh_state(bh);
1027 if (try_to_free)
1028 release_buffer_page(bh); /* Drops bh reference */
1029 else
1030 __brelse(bh);
1031 cond_resched_lock(&journal->j_list_lock);
1032 }
1033 spin_unlock(&journal->j_list_lock);
1034 /*
1035 * This is a bit sleazy. We use j_list_lock to protect transition
1036 * of a transaction into T_FINISHED state and calling
1037 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1038 * other checkpointing code processing the transaction...
1039 */
1040 write_lock(&journal->j_state_lock);
1041 spin_lock(&journal->j_list_lock);
1042 /*
1043 * Now recheck if some buffers did not get attached to the transaction
1044 * while the lock was dropped...
1045 */
1046 if (commit_transaction->t_forget) {
1047 spin_unlock(&journal->j_list_lock);
1048 write_unlock(&journal->j_state_lock);
1049 goto restart_loop;
1050 }
1051
1052 /* Add the transaction to the checkpoint list
1053 * __journal_remove_checkpoint() can not destroy transaction
1054 * under us because it is not marked as T_FINISHED yet */
1055 if (journal->j_checkpoint_transactions == NULL) {
1056 journal->j_checkpoint_transactions = commit_transaction;
1057 commit_transaction->t_cpnext = commit_transaction;
1058 commit_transaction->t_cpprev = commit_transaction;
1059 } else {
1060 commit_transaction->t_cpnext =
1061 journal->j_checkpoint_transactions;
1062 commit_transaction->t_cpprev =
1063 commit_transaction->t_cpnext->t_cpprev;
1064 commit_transaction->t_cpnext->t_cpprev =
1065 commit_transaction;
1066 commit_transaction->t_cpprev->t_cpnext =
1067 commit_transaction;
1068 }
1069 spin_unlock(&journal->j_list_lock);
1070
1071 /* Done with this transaction! */
1072
1073 jbd_debug(3, "JBD2: commit phase 7\n");
1074
1075 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1076
1077 commit_transaction->t_start = jiffies;
1078 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1079 commit_transaction->t_start);
1080
1081 /*
1082 * File the transaction statistics
1083 */
1084 stats.ts_tid = commit_transaction->t_tid;
1085 stats.run.rs_handle_count =
1086 atomic_read(&commit_transaction->t_handle_count);
1087 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1088 commit_transaction->t_tid, &stats.run);
1089 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1090
1091 commit_transaction->t_state = T_COMMIT_CALLBACK;
1092 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1093 journal->j_commit_sequence = commit_transaction->t_tid;
1094 journal->j_committing_transaction = NULL;
1095 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1096
1097 /*
1098 * weight the commit time higher than the average time so we don't
1099 * react too strongly to vast changes in the commit time
1100 */
1101 if (likely(journal->j_average_commit_time))
1102 journal->j_average_commit_time = (commit_time +
1103 journal->j_average_commit_time*3) / 4;
1104 else
1105 journal->j_average_commit_time = commit_time;
1106
1107 write_unlock(&journal->j_state_lock);
1108
1109 if (journal->j_commit_callback)
1110 journal->j_commit_callback(journal, commit_transaction);
1111
1112 trace_jbd2_end_commit(journal, commit_transaction);
1113 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1114 journal->j_commit_sequence, journal->j_tail_sequence);
1115
1116 write_lock(&journal->j_state_lock);
1117 spin_lock(&journal->j_list_lock);
1118 commit_transaction->t_state = T_FINISHED;
1119 /* Check if the transaction can be dropped now that we are finished */
1120 if (commit_transaction->t_checkpoint_list == NULL &&
1121 commit_transaction->t_checkpoint_io_list == NULL) {
1122 __jbd2_journal_drop_transaction(journal, commit_transaction);
1123 jbd2_journal_free_transaction(commit_transaction);
1124 }
1125 spin_unlock(&journal->j_list_lock);
1126 write_unlock(&journal->j_state_lock);
1127 wake_up(&journal->j_wait_done_commit);
1128
1129 /*
1130 * Calculate overall stats
1131 */
1132 spin_lock(&journal->j_history_lock);
1133 journal->j_stats.ts_tid++;
1134 journal->j_stats.ts_requested += stats.ts_requested;
1135 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1136 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1137 journal->j_stats.run.rs_running += stats.run.rs_running;
1138 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1139 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1140 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1141 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1142 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1143 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1144 spin_unlock(&journal->j_history_lock);
1145}