Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso...
[linux-2.6-microblaze.git] / fs / jbd2 / commit.c
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  */
32 static 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  */
63 static void release_buffer_page(struct buffer_head *bh)
64 {
65         struct folio *folio;
66         struct page *page;
67
68         if (buffer_dirty(bh))
69                 goto nope;
70         if (atomic_read(&bh->b_count) != 1)
71                 goto nope;
72         page = bh->b_page;
73         if (!page)
74                 goto nope;
75         folio = page_folio(page);
76         if (folio->mapping)
77                 goto nope;
78
79         /* OK, it's a truncated page */
80         if (!folio_trylock(folio))
81                 goto nope;
82
83         folio_get(folio);
84         __brelse(bh);
85         try_to_free_buffers(folio);
86         folio_unlock(folio);
87         folio_put(folio);
88         return;
89
90 nope:
91         __brelse(bh);
92 }
93
94 static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
95 {
96         struct commit_header *h;
97         __u32 csum;
98
99         if (!jbd2_journal_has_csum_v2or3(j))
100                 return;
101
102         h = (struct commit_header *)(bh->b_data);
103         h->h_chksum_type = 0;
104         h->h_chksum_size = 0;
105         h->h_chksum[0] = 0;
106         csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
107         h->h_chksum[0] = cpu_to_be32(csum);
108 }
109
110 /*
111  * Done it all: now submit the commit record.  We should have
112  * cleaned up our previous buffers by now, so if we are in abort
113  * mode we can now just skip the rest of the journal write
114  * entirely.
115  *
116  * Returns 1 if the journal needs to be aborted or 0 on success
117  */
118 static int journal_submit_commit_record(journal_t *journal,
119                                         transaction_t *commit_transaction,
120                                         struct buffer_head **cbh,
121                                         __u32 crc32_sum)
122 {
123         struct commit_header *tmp;
124         struct buffer_head *bh;
125         int ret;
126         struct timespec64 now;
127
128         *cbh = NULL;
129
130         if (is_journal_aborted(journal))
131                 return 0;
132
133         bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
134                                                 JBD2_COMMIT_BLOCK);
135         if (!bh)
136                 return 1;
137
138         tmp = (struct commit_header *)bh->b_data;
139         ktime_get_coarse_real_ts64(&now);
140         tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
141         tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
142
143         if (jbd2_has_feature_checksum(journal)) {
144                 tmp->h_chksum_type      = JBD2_CRC32_CHKSUM;
145                 tmp->h_chksum_size      = JBD2_CRC32_CHKSUM_SIZE;
146                 tmp->h_chksum[0]        = cpu_to_be32(crc32_sum);
147         }
148         jbd2_commit_block_csum_set(journal, bh);
149
150         BUFFER_TRACE(bh, "submit commit block");
151         lock_buffer(bh);
152         clear_buffer_dirty(bh);
153         set_buffer_uptodate(bh);
154         bh->b_end_io = journal_end_buffer_io_sync;
155
156         if (journal->j_flags & JBD2_BARRIER &&
157             !jbd2_has_feature_async_commit(journal))
158                 ret = submit_bh(REQ_OP_WRITE | REQ_SYNC | REQ_PREFLUSH |
159                                 REQ_FUA, bh);
160         else
161                 ret = submit_bh(REQ_OP_WRITE | REQ_SYNC, bh);
162
163         *cbh = bh;
164         return ret;
165 }
166
167 /*
168  * This function along with journal_submit_commit_record
169  * allows to write the commit record asynchronously.
170  */
171 static int journal_wait_on_commit_record(journal_t *journal,
172                                          struct buffer_head *bh)
173 {
174         int ret = 0;
175
176         clear_buffer_dirty(bh);
177         wait_on_buffer(bh);
178
179         if (unlikely(!buffer_uptodate(bh)))
180                 ret = -EIO;
181         put_bh(bh);            /* One for getblk() */
182
183         return ret;
184 }
185
186 /*
187  * write the filemap data using writepage() address_space_operations.
188  * We don't do block allocation here even for delalloc. We don't
189  * use writepages() because with delayed allocation we may be doing
190  * block allocation in writepages().
191  */
192 int jbd2_journal_submit_inode_data_buffers(struct jbd2_inode *jinode)
193 {
194         struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
195         struct writeback_control wbc = {
196                 .sync_mode =  WB_SYNC_ALL,
197                 .nr_to_write = mapping->nrpages * 2,
198                 .range_start = jinode->i_dirty_start,
199                 .range_end = jinode->i_dirty_end,
200         };
201
202         /*
203          * submit the inode data buffers. We use writepage
204          * instead of writepages. Because writepages can do
205          * block allocation with delalloc. We need to write
206          * only allocated blocks here.
207          */
208         return generic_writepages(mapping, &wbc);
209 }
210
211 /* Send all the data buffers related to an inode */
212 int jbd2_submit_inode_data(struct jbd2_inode *jinode)
213 {
214
215         if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
216                 return 0;
217
218         trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
219         return jbd2_journal_submit_inode_data_buffers(jinode);
220
221 }
222 EXPORT_SYMBOL(jbd2_submit_inode_data);
223
224 int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
225 {
226         if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
227                 !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
228                 return 0;
229         return filemap_fdatawait_range_keep_errors(
230                 jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
231                 jinode->i_dirty_end);
232 }
233 EXPORT_SYMBOL(jbd2_wait_inode_data);
234
235 /*
236  * Submit all the data buffers of inode associated with the transaction to
237  * disk.
238  *
239  * We are in a committing transaction. Therefore no new inode can be added to
240  * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
241  * operate on from being released while we write out pages.
242  */
243 static int journal_submit_data_buffers(journal_t *journal,
244                 transaction_t *commit_transaction)
245 {
246         struct jbd2_inode *jinode;
247         int err, ret = 0;
248
249         spin_lock(&journal->j_list_lock);
250         list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
251                 if (!(jinode->i_flags & JI_WRITE_DATA))
252                         continue;
253                 jinode->i_flags |= JI_COMMIT_RUNNING;
254                 spin_unlock(&journal->j_list_lock);
255                 /* submit the inode data buffers. */
256                 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
257                 if (journal->j_submit_inode_data_buffers) {
258                         err = journal->j_submit_inode_data_buffers(jinode);
259                         if (!ret)
260                                 ret = err;
261                 }
262                 spin_lock(&journal->j_list_lock);
263                 J_ASSERT(jinode->i_transaction == commit_transaction);
264                 jinode->i_flags &= ~JI_COMMIT_RUNNING;
265                 smp_mb();
266                 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
267         }
268         spin_unlock(&journal->j_list_lock);
269         return ret;
270 }
271
272 int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
273 {
274         struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
275
276         return filemap_fdatawait_range_keep_errors(mapping,
277                                                    jinode->i_dirty_start,
278                                                    jinode->i_dirty_end);
279 }
280
281 /*
282  * Wait for data submitted for writeout, refile inodes to proper
283  * transaction if needed.
284  *
285  */
286 static int journal_finish_inode_data_buffers(journal_t *journal,
287                 transaction_t *commit_transaction)
288 {
289         struct jbd2_inode *jinode, *next_i;
290         int err, ret = 0;
291
292         /* For locking, see the comment in journal_submit_data_buffers() */
293         spin_lock(&journal->j_list_lock);
294         list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
295                 if (!(jinode->i_flags & JI_WAIT_DATA))
296                         continue;
297                 jinode->i_flags |= JI_COMMIT_RUNNING;
298                 spin_unlock(&journal->j_list_lock);
299                 /* wait for the inode data buffers writeout. */
300                 if (journal->j_finish_inode_data_buffers) {
301                         err = journal->j_finish_inode_data_buffers(jinode);
302                         if (!ret)
303                                 ret = err;
304                 }
305                 spin_lock(&journal->j_list_lock);
306                 jinode->i_flags &= ~JI_COMMIT_RUNNING;
307                 smp_mb();
308                 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
309         }
310
311         /* Now refile inode to proper lists */
312         list_for_each_entry_safe(jinode, next_i,
313                                  &commit_transaction->t_inode_list, i_list) {
314                 list_del(&jinode->i_list);
315                 if (jinode->i_next_transaction) {
316                         jinode->i_transaction = jinode->i_next_transaction;
317                         jinode->i_next_transaction = NULL;
318                         list_add(&jinode->i_list,
319                                 &jinode->i_transaction->t_inode_list);
320                 } else {
321                         jinode->i_transaction = NULL;
322                         jinode->i_dirty_start = 0;
323                         jinode->i_dirty_end = 0;
324                 }
325         }
326         spin_unlock(&journal->j_list_lock);
327
328         return ret;
329 }
330
331 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
332 {
333         struct page *page = bh->b_page;
334         char *addr;
335         __u32 checksum;
336
337         addr = kmap_atomic(page);
338         checksum = crc32_be(crc32_sum,
339                 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
340         kunmap_atomic(addr);
341
342         return checksum;
343 }
344
345 static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
346                                    unsigned long long block)
347 {
348         tag->t_blocknr = cpu_to_be32(block & (u32)~0);
349         if (jbd2_has_feature_64bit(j))
350                 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
351 }
352
353 static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
354                                     struct buffer_head *bh, __u32 sequence)
355 {
356         journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
357         struct page *page = bh->b_page;
358         __u8 *addr;
359         __u32 csum32;
360         __be32 seq;
361
362         if (!jbd2_journal_has_csum_v2or3(j))
363                 return;
364
365         seq = cpu_to_be32(sequence);
366         addr = kmap_atomic(page);
367         csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
368         csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
369                              bh->b_size);
370         kunmap_atomic(addr);
371
372         if (jbd2_has_feature_csum3(j))
373                 tag3->t_checksum = cpu_to_be32(csum32);
374         else
375                 tag->t_checksum = cpu_to_be16(csum32);
376 }
377 /*
378  * jbd2_journal_commit_transaction
379  *
380  * The primary function for committing a transaction to the log.  This
381  * function is called by the journal thread to begin a complete commit.
382  */
383 void jbd2_journal_commit_transaction(journal_t *journal)
384 {
385         struct transaction_stats_s stats;
386         transaction_t *commit_transaction;
387         struct journal_head *jh;
388         struct buffer_head *descriptor;
389         struct buffer_head **wbuf = journal->j_wbuf;
390         int bufs;
391         int flags;
392         int err;
393         unsigned long long blocknr;
394         ktime_t start_time;
395         u64 commit_time;
396         char *tagp = NULL;
397         journal_block_tag_t *tag = NULL;
398         int space_left = 0;
399         int first_tag = 0;
400         int tag_flag;
401         int i;
402         int tag_bytes = journal_tag_bytes(journal);
403         struct buffer_head *cbh = NULL; /* For transactional checksums */
404         __u32 crc32_sum = ~0;
405         struct blk_plug plug;
406         /* Tail of the journal */
407         unsigned long first_block;
408         tid_t first_tid;
409         int update_tail;
410         int csum_size = 0;
411         LIST_HEAD(io_bufs);
412         LIST_HEAD(log_bufs);
413
414         if (jbd2_journal_has_csum_v2or3(journal))
415                 csum_size = sizeof(struct jbd2_journal_block_tail);
416
417         /*
418          * First job: lock down the current transaction and wait for
419          * all outstanding updates to complete.
420          */
421
422         /* Do we need to erase the effects of a prior jbd2_journal_flush? */
423         if (journal->j_flags & JBD2_FLUSHED) {
424                 jbd2_debug(3, "super block updated\n");
425                 mutex_lock_io(&journal->j_checkpoint_mutex);
426                 /*
427                  * We hold j_checkpoint_mutex so tail cannot change under us.
428                  * We don't need any special data guarantees for writing sb
429                  * since journal is empty and it is ok for write to be
430                  * flushed only with transaction commit.
431                  */
432                 jbd2_journal_update_sb_log_tail(journal,
433                                                 journal->j_tail_sequence,
434                                                 journal->j_tail,
435                                                 REQ_SYNC);
436                 mutex_unlock(&journal->j_checkpoint_mutex);
437         } else {
438                 jbd2_debug(3, "superblock not updated\n");
439         }
440
441         J_ASSERT(journal->j_running_transaction != NULL);
442         J_ASSERT(journal->j_committing_transaction == NULL);
443
444         write_lock(&journal->j_state_lock);
445         journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
446         while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
447                 DEFINE_WAIT(wait);
448
449                 prepare_to_wait(&journal->j_fc_wait, &wait,
450                                 TASK_UNINTERRUPTIBLE);
451                 write_unlock(&journal->j_state_lock);
452                 schedule();
453                 write_lock(&journal->j_state_lock);
454                 finish_wait(&journal->j_fc_wait, &wait);
455                 /*
456                  * TODO: by blocking fast commits here, we are increasing
457                  * fsync() latency slightly. Strictly speaking, we don't need
458                  * to block fast commits until the transaction enters T_FLUSH
459                  * state. So an optimization is possible where we block new fast
460                  * commits here and wait for existing ones to complete
461                  * just before we enter T_FLUSH. That way, the existing fast
462                  * commits and this full commit can proceed parallely.
463                  */
464         }
465         write_unlock(&journal->j_state_lock);
466
467         commit_transaction = journal->j_running_transaction;
468
469         trace_jbd2_start_commit(journal, commit_transaction);
470         jbd2_debug(1, "JBD2: starting commit of transaction %d\n",
471                         commit_transaction->t_tid);
472
473         write_lock(&journal->j_state_lock);
474         journal->j_fc_off = 0;
475         J_ASSERT(commit_transaction->t_state == T_RUNNING);
476         commit_transaction->t_state = T_LOCKED;
477
478         trace_jbd2_commit_locking(journal, commit_transaction);
479         stats.run.rs_wait = commit_transaction->t_max_wait;
480         stats.run.rs_request_delay = 0;
481         stats.run.rs_locked = jiffies;
482         if (commit_transaction->t_requested)
483                 stats.run.rs_request_delay =
484                         jbd2_time_diff(commit_transaction->t_requested,
485                                        stats.run.rs_locked);
486         stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
487                                               stats.run.rs_locked);
488
489         // waits for any t_updates to finish
490         jbd2_journal_wait_updates(journal);
491
492         commit_transaction->t_state = T_SWITCH;
493
494         J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
495                         journal->j_max_transaction_buffers);
496
497         /*
498          * First thing we are allowed to do is to discard any remaining
499          * BJ_Reserved buffers.  Note, it is _not_ permissible to assume
500          * that there are no such buffers: if a large filesystem
501          * operation like a truncate needs to split itself over multiple
502          * transactions, then it may try to do a jbd2_journal_restart() while
503          * there are still BJ_Reserved buffers outstanding.  These must
504          * be released cleanly from the current transaction.
505          *
506          * In this case, the filesystem must still reserve write access
507          * again before modifying the buffer in the new transaction, but
508          * we do not require it to remember exactly which old buffers it
509          * has reserved.  This is consistent with the existing behaviour
510          * that multiple jbd2_journal_get_write_access() calls to the same
511          * buffer are perfectly permissible.
512          * We use journal->j_state_lock here to serialize processing of
513          * t_reserved_list with eviction of buffers from journal_unmap_buffer().
514          */
515         while (commit_transaction->t_reserved_list) {
516                 jh = commit_transaction->t_reserved_list;
517                 JBUFFER_TRACE(jh, "reserved, unused: refile");
518                 /*
519                  * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
520                  * leave undo-committed data.
521                  */
522                 if (jh->b_committed_data) {
523                         struct buffer_head *bh = jh2bh(jh);
524
525                         spin_lock(&jh->b_state_lock);
526                         jbd2_free(jh->b_committed_data, bh->b_size);
527                         jh->b_committed_data = NULL;
528                         spin_unlock(&jh->b_state_lock);
529                 }
530                 jbd2_journal_refile_buffer(journal, jh);
531         }
532
533         write_unlock(&journal->j_state_lock);
534         /*
535          * Now try to drop any written-back buffers from the journal's
536          * checkpoint lists.  We do this *before* commit because it potentially
537          * frees some memory
538          */
539         spin_lock(&journal->j_list_lock);
540         __jbd2_journal_clean_checkpoint_list(journal, false);
541         spin_unlock(&journal->j_list_lock);
542
543         jbd2_debug(3, "JBD2: commit phase 1\n");
544
545         /*
546          * Clear revoked flag to reflect there is no revoked buffers
547          * in the next transaction which is going to be started.
548          */
549         jbd2_clear_buffer_revoked_flags(journal);
550
551         /*
552          * Switch to a new revoke table.
553          */
554         jbd2_journal_switch_revoke_table(journal);
555
556         write_lock(&journal->j_state_lock);
557         /*
558          * Reserved credits cannot be claimed anymore, free them
559          */
560         atomic_sub(atomic_read(&journal->j_reserved_credits),
561                    &commit_transaction->t_outstanding_credits);
562
563         trace_jbd2_commit_flushing(journal, commit_transaction);
564         stats.run.rs_flushing = jiffies;
565         stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
566                                              stats.run.rs_flushing);
567
568         commit_transaction->t_state = T_FLUSH;
569         journal->j_committing_transaction = commit_transaction;
570         journal->j_running_transaction = NULL;
571         start_time = ktime_get();
572         commit_transaction->t_log_start = journal->j_head;
573         wake_up(&journal->j_wait_transaction_locked);
574         write_unlock(&journal->j_state_lock);
575
576         jbd2_debug(3, "JBD2: commit phase 2a\n");
577
578         /*
579          * Now start flushing things to disk, in the order they appear
580          * on the transaction lists.  Data blocks go first.
581          */
582         err = journal_submit_data_buffers(journal, commit_transaction);
583         if (err)
584                 jbd2_journal_abort(journal, err);
585
586         blk_start_plug(&plug);
587         jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
588
589         jbd2_debug(3, "JBD2: commit phase 2b\n");
590
591         /*
592          * Way to go: we have now written out all of the data for a
593          * transaction!  Now comes the tricky part: we need to write out
594          * metadata.  Loop over the transaction's entire buffer list:
595          */
596         write_lock(&journal->j_state_lock);
597         commit_transaction->t_state = T_COMMIT;
598         write_unlock(&journal->j_state_lock);
599
600         trace_jbd2_commit_logging(journal, commit_transaction);
601         stats.run.rs_logging = jiffies;
602         stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
603                                                stats.run.rs_logging);
604         stats.run.rs_blocks = commit_transaction->t_nr_buffers;
605         stats.run.rs_blocks_logged = 0;
606
607         J_ASSERT(commit_transaction->t_nr_buffers <=
608                  atomic_read(&commit_transaction->t_outstanding_credits));
609
610         err = 0;
611         bufs = 0;
612         descriptor = NULL;
613         while (commit_transaction->t_buffers) {
614
615                 /* Find the next buffer to be journaled... */
616
617                 jh = commit_transaction->t_buffers;
618
619                 /* If we're in abort mode, we just un-journal the buffer and
620                    release it. */
621
622                 if (is_journal_aborted(journal)) {
623                         clear_buffer_jbddirty(jh2bh(jh));
624                         JBUFFER_TRACE(jh, "journal is aborting: refile");
625                         jbd2_buffer_abort_trigger(jh,
626                                                   jh->b_frozen_data ?
627                                                   jh->b_frozen_triggers :
628                                                   jh->b_triggers);
629                         jbd2_journal_refile_buffer(journal, jh);
630                         /* If that was the last one, we need to clean up
631                          * any descriptor buffers which may have been
632                          * already allocated, even if we are now
633                          * aborting. */
634                         if (!commit_transaction->t_buffers)
635                                 goto start_journal_io;
636                         continue;
637                 }
638
639                 /* Make sure we have a descriptor block in which to
640                    record the metadata buffer. */
641
642                 if (!descriptor) {
643                         J_ASSERT (bufs == 0);
644
645                         jbd2_debug(4, "JBD2: get descriptor\n");
646
647                         descriptor = jbd2_journal_get_descriptor_buffer(
648                                                         commit_transaction,
649                                                         JBD2_DESCRIPTOR_BLOCK);
650                         if (!descriptor) {
651                                 jbd2_journal_abort(journal, -EIO);
652                                 continue;
653                         }
654
655                         jbd2_debug(4, "JBD2: got buffer %llu (%p)\n",
656                                 (unsigned long long)descriptor->b_blocknr,
657                                 descriptor->b_data);
658                         tagp = &descriptor->b_data[sizeof(journal_header_t)];
659                         space_left = descriptor->b_size -
660                                                 sizeof(journal_header_t);
661                         first_tag = 1;
662                         set_buffer_jwrite(descriptor);
663                         set_buffer_dirty(descriptor);
664                         wbuf[bufs++] = descriptor;
665
666                         /* Record it so that we can wait for IO
667                            completion later */
668                         BUFFER_TRACE(descriptor, "ph3: file as descriptor");
669                         jbd2_file_log_bh(&log_bufs, descriptor);
670                 }
671
672                 /* Where is the buffer to be written? */
673
674                 err = jbd2_journal_next_log_block(journal, &blocknr);
675                 /* If the block mapping failed, just abandon the buffer
676                    and repeat this loop: we'll fall into the
677                    refile-on-abort condition above. */
678                 if (err) {
679                         jbd2_journal_abort(journal, err);
680                         continue;
681                 }
682
683                 /*
684                  * start_this_handle() uses t_outstanding_credits to determine
685                  * the free space in the log.
686                  */
687                 atomic_dec(&commit_transaction->t_outstanding_credits);
688
689                 /* Bump b_count to prevent truncate from stumbling over
690                    the shadowed buffer!  @@@ This can go if we ever get
691                    rid of the shadow pairing of buffers. */
692                 atomic_inc(&jh2bh(jh)->b_count);
693
694                 /*
695                  * Make a temporary IO buffer with which to write it out
696                  * (this will requeue the metadata buffer to BJ_Shadow).
697                  */
698                 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
699                 JBUFFER_TRACE(jh, "ph3: write metadata");
700                 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
701                                                 jh, &wbuf[bufs], blocknr);
702                 if (flags < 0) {
703                         jbd2_journal_abort(journal, flags);
704                         continue;
705                 }
706                 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
707
708                 /* Record the new block's tag in the current descriptor
709                    buffer */
710
711                 tag_flag = 0;
712                 if (flags & 1)
713                         tag_flag |= JBD2_FLAG_ESCAPE;
714                 if (!first_tag)
715                         tag_flag |= JBD2_FLAG_SAME_UUID;
716
717                 tag = (journal_block_tag_t *) tagp;
718                 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
719                 tag->t_flags = cpu_to_be16(tag_flag);
720                 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
721                                         commit_transaction->t_tid);
722                 tagp += tag_bytes;
723                 space_left -= tag_bytes;
724                 bufs++;
725
726                 if (first_tag) {
727                         memcpy (tagp, journal->j_uuid, 16);
728                         tagp += 16;
729                         space_left -= 16;
730                         first_tag = 0;
731                 }
732
733                 /* If there's no more to do, or if the descriptor is full,
734                    let the IO rip! */
735
736                 if (bufs == journal->j_wbufsize ||
737                     commit_transaction->t_buffers == NULL ||
738                     space_left < tag_bytes + 16 + csum_size) {
739
740                         jbd2_debug(4, "JBD2: Submit %d IOs\n", bufs);
741
742                         /* Write an end-of-descriptor marker before
743                            submitting the IOs.  "tag" still points to
744                            the last tag we set up. */
745
746                         tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
747 start_journal_io:
748                         if (descriptor)
749                                 jbd2_descriptor_block_csum_set(journal,
750                                                         descriptor);
751
752                         for (i = 0; i < bufs; i++) {
753                                 struct buffer_head *bh = wbuf[i];
754                                 /*
755                                  * Compute checksum.
756                                  */
757                                 if (jbd2_has_feature_checksum(journal)) {
758                                         crc32_sum =
759                                             jbd2_checksum_data(crc32_sum, bh);
760                                 }
761
762                                 lock_buffer(bh);
763                                 clear_buffer_dirty(bh);
764                                 set_buffer_uptodate(bh);
765                                 bh->b_end_io = journal_end_buffer_io_sync;
766                                 submit_bh(REQ_OP_WRITE | REQ_SYNC, bh);
767                         }
768                         cond_resched();
769
770                         /* Force a new descriptor to be generated next
771                            time round the loop. */
772                         descriptor = NULL;
773                         bufs = 0;
774                 }
775         }
776
777         err = journal_finish_inode_data_buffers(journal, commit_transaction);
778         if (err) {
779                 printk(KERN_WARNING
780                         "JBD2: Detected IO errors while flushing file data "
781                        "on %s\n", journal->j_devname);
782                 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
783                         jbd2_journal_abort(journal, err);
784                 err = 0;
785         }
786
787         /*
788          * Get current oldest transaction in the log before we issue flush
789          * to the filesystem device. After the flush we can be sure that
790          * blocks of all older transactions are checkpointed to persistent
791          * storage and we will be safe to update journal start in the
792          * superblock with the numbers we get here.
793          */
794         update_tail =
795                 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
796
797         write_lock(&journal->j_state_lock);
798         if (update_tail) {
799                 long freed = first_block - journal->j_tail;
800
801                 if (first_block < journal->j_tail)
802                         freed += journal->j_last - journal->j_first;
803                 /* Update tail only if we free significant amount of space */
804                 if (freed < jbd2_journal_get_max_txn_bufs(journal))
805                         update_tail = 0;
806         }
807         J_ASSERT(commit_transaction->t_state == T_COMMIT);
808         commit_transaction->t_state = T_COMMIT_DFLUSH;
809         write_unlock(&journal->j_state_lock);
810
811         /*
812          * If the journal is not located on the file system device,
813          * then we must flush the file system device before we issue
814          * the commit record
815          */
816         if (commit_transaction->t_need_data_flush &&
817             (journal->j_fs_dev != journal->j_dev) &&
818             (journal->j_flags & JBD2_BARRIER))
819                 blkdev_issue_flush(journal->j_fs_dev);
820
821         /* Done it all: now write the commit record asynchronously. */
822         if (jbd2_has_feature_async_commit(journal)) {
823                 err = journal_submit_commit_record(journal, commit_transaction,
824                                                  &cbh, crc32_sum);
825                 if (err)
826                         jbd2_journal_abort(journal, err);
827         }
828
829         blk_finish_plug(&plug);
830
831         /* Lo and behold: we have just managed to send a transaction to
832            the log.  Before we can commit it, wait for the IO so far to
833            complete.  Control buffers being written are on the
834            transaction's t_log_list queue, and metadata buffers are on
835            the io_bufs list.
836
837            Wait for the buffers in reverse order.  That way we are
838            less likely to be woken up until all IOs have completed, and
839            so we incur less scheduling load.
840         */
841
842         jbd2_debug(3, "JBD2: commit phase 3\n");
843
844         while (!list_empty(&io_bufs)) {
845                 struct buffer_head *bh = list_entry(io_bufs.prev,
846                                                     struct buffer_head,
847                                                     b_assoc_buffers);
848
849                 wait_on_buffer(bh);
850                 cond_resched();
851
852                 if (unlikely(!buffer_uptodate(bh)))
853                         err = -EIO;
854                 jbd2_unfile_log_bh(bh);
855                 stats.run.rs_blocks_logged++;
856
857                 /*
858                  * The list contains temporary buffer heads created by
859                  * jbd2_journal_write_metadata_buffer().
860                  */
861                 BUFFER_TRACE(bh, "dumping temporary bh");
862                 __brelse(bh);
863                 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
864                 free_buffer_head(bh);
865
866                 /* We also have to refile the corresponding shadowed buffer */
867                 jh = commit_transaction->t_shadow_list->b_tprev;
868                 bh = jh2bh(jh);
869                 clear_buffer_jwrite(bh);
870                 J_ASSERT_BH(bh, buffer_jbddirty(bh));
871                 J_ASSERT_BH(bh, !buffer_shadow(bh));
872
873                 /* The metadata is now released for reuse, but we need
874                    to remember it against this transaction so that when
875                    we finally commit, we can do any checkpointing
876                    required. */
877                 JBUFFER_TRACE(jh, "file as BJ_Forget");
878                 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
879                 JBUFFER_TRACE(jh, "brelse shadowed buffer");
880                 __brelse(bh);
881         }
882
883         J_ASSERT (commit_transaction->t_shadow_list == NULL);
884
885         jbd2_debug(3, "JBD2: commit phase 4\n");
886
887         /* Here we wait for the revoke record and descriptor record buffers */
888         while (!list_empty(&log_bufs)) {
889                 struct buffer_head *bh;
890
891                 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
892                 wait_on_buffer(bh);
893                 cond_resched();
894
895                 if (unlikely(!buffer_uptodate(bh)))
896                         err = -EIO;
897
898                 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
899                 clear_buffer_jwrite(bh);
900                 jbd2_unfile_log_bh(bh);
901                 stats.run.rs_blocks_logged++;
902                 __brelse(bh);           /* One for getblk */
903                 /* AKPM: bforget here */
904         }
905
906         if (err)
907                 jbd2_journal_abort(journal, err);
908
909         jbd2_debug(3, "JBD2: commit phase 5\n");
910         write_lock(&journal->j_state_lock);
911         J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
912         commit_transaction->t_state = T_COMMIT_JFLUSH;
913         write_unlock(&journal->j_state_lock);
914
915         if (!jbd2_has_feature_async_commit(journal)) {
916                 err = journal_submit_commit_record(journal, commit_transaction,
917                                                 &cbh, crc32_sum);
918                 if (err)
919                         jbd2_journal_abort(journal, err);
920         }
921         if (cbh)
922                 err = journal_wait_on_commit_record(journal, cbh);
923         stats.run.rs_blocks_logged++;
924         if (jbd2_has_feature_async_commit(journal) &&
925             journal->j_flags & JBD2_BARRIER) {
926                 blkdev_issue_flush(journal->j_dev);
927         }
928
929         if (err)
930                 jbd2_journal_abort(journal, err);
931
932         WARN_ON_ONCE(
933                 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
934
935         /*
936          * Now disk caches for filesystem device are flushed so we are safe to
937          * erase checkpointed transactions from the log by updating journal
938          * superblock.
939          */
940         if (update_tail)
941                 jbd2_update_log_tail(journal, first_tid, first_block);
942
943         /* End of a transaction!  Finally, we can do checkpoint
944            processing: any buffers committed as a result of this
945            transaction can be removed from any checkpoint list it was on
946            before. */
947
948         jbd2_debug(3, "JBD2: commit phase 6\n");
949
950         J_ASSERT(list_empty(&commit_transaction->t_inode_list));
951         J_ASSERT(commit_transaction->t_buffers == NULL);
952         J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
953         J_ASSERT(commit_transaction->t_shadow_list == NULL);
954
955 restart_loop:
956         /*
957          * As there are other places (journal_unmap_buffer()) adding buffers
958          * to this list we have to be careful and hold the j_list_lock.
959          */
960         spin_lock(&journal->j_list_lock);
961         while (commit_transaction->t_forget) {
962                 transaction_t *cp_transaction;
963                 struct buffer_head *bh;
964                 int try_to_free = 0;
965                 bool drop_ref;
966
967                 jh = commit_transaction->t_forget;
968                 spin_unlock(&journal->j_list_lock);
969                 bh = jh2bh(jh);
970                 /*
971                  * Get a reference so that bh cannot be freed before we are
972                  * done with it.
973                  */
974                 get_bh(bh);
975                 spin_lock(&jh->b_state_lock);
976                 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
977
978                 /*
979                  * If there is undo-protected committed data against
980                  * this buffer, then we can remove it now.  If it is a
981                  * buffer needing such protection, the old frozen_data
982                  * field now points to a committed version of the
983                  * buffer, so rotate that field to the new committed
984                  * data.
985                  *
986                  * Otherwise, we can just throw away the frozen data now.
987                  *
988                  * We also know that the frozen data has already fired
989                  * its triggers if they exist, so we can clear that too.
990                  */
991                 if (jh->b_committed_data) {
992                         jbd2_free(jh->b_committed_data, bh->b_size);
993                         jh->b_committed_data = NULL;
994                         if (jh->b_frozen_data) {
995                                 jh->b_committed_data = jh->b_frozen_data;
996                                 jh->b_frozen_data = NULL;
997                                 jh->b_frozen_triggers = NULL;
998                         }
999                 } else if (jh->b_frozen_data) {
1000                         jbd2_free(jh->b_frozen_data, bh->b_size);
1001                         jh->b_frozen_data = NULL;
1002                         jh->b_frozen_triggers = NULL;
1003                 }
1004
1005                 spin_lock(&journal->j_list_lock);
1006                 cp_transaction = jh->b_cp_transaction;
1007                 if (cp_transaction) {
1008                         JBUFFER_TRACE(jh, "remove from old cp transaction");
1009                         cp_transaction->t_chp_stats.cs_dropped++;
1010                         __jbd2_journal_remove_checkpoint(jh);
1011                 }
1012
1013                 /* Only re-checkpoint the buffer_head if it is marked
1014                  * dirty.  If the buffer was added to the BJ_Forget list
1015                  * by jbd2_journal_forget, it may no longer be dirty and
1016                  * there's no point in keeping a checkpoint record for
1017                  * it. */
1018
1019                 /*
1020                  * A buffer which has been freed while still being journaled
1021                  * by a previous transaction, refile the buffer to BJ_Forget of
1022                  * the running transaction. If the just committed transaction
1023                  * contains "add to orphan" operation, we can completely
1024                  * invalidate the buffer now. We are rather through in that
1025                  * since the buffer may be still accessible when blocksize <
1026                  * pagesize and it is attached to the last partial page.
1027                  */
1028                 if (buffer_freed(bh) && !jh->b_next_transaction) {
1029                         struct address_space *mapping;
1030
1031                         clear_buffer_freed(bh);
1032                         clear_buffer_jbddirty(bh);
1033
1034                         /*
1035                          * Block device buffers need to stay mapped all the
1036                          * time, so it is enough to clear buffer_jbddirty and
1037                          * buffer_freed bits. For the file mapping buffers (i.e.
1038                          * journalled data) we need to unmap buffer and clear
1039                          * more bits. We also need to be careful about the check
1040                          * because the data page mapping can get cleared under
1041                          * our hands. Note that if mapping == NULL, we don't
1042                          * need to make buffer unmapped because the page is
1043                          * already detached from the mapping and buffers cannot
1044                          * get reused.
1045                          */
1046                         mapping = READ_ONCE(bh->b_page->mapping);
1047                         if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1048                                 clear_buffer_mapped(bh);
1049                                 clear_buffer_new(bh);
1050                                 clear_buffer_req(bh);
1051                                 bh->b_bdev = NULL;
1052                         }
1053                 }
1054
1055                 if (buffer_jbddirty(bh)) {
1056                         JBUFFER_TRACE(jh, "add to new checkpointing trans");
1057                         __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1058                         if (is_journal_aborted(journal))
1059                                 clear_buffer_jbddirty(bh);
1060                 } else {
1061                         J_ASSERT_BH(bh, !buffer_dirty(bh));
1062                         /*
1063                          * The buffer on BJ_Forget list and not jbddirty means
1064                          * it has been freed by this transaction and hence it
1065                          * could not have been reallocated until this
1066                          * transaction has committed. *BUT* it could be
1067                          * reallocated once we have written all the data to
1068                          * disk and before we process the buffer on BJ_Forget
1069                          * list.
1070                          */
1071                         if (!jh->b_next_transaction)
1072                                 try_to_free = 1;
1073                 }
1074                 JBUFFER_TRACE(jh, "refile or unfile buffer");
1075                 drop_ref = __jbd2_journal_refile_buffer(jh);
1076                 spin_unlock(&jh->b_state_lock);
1077                 if (drop_ref)
1078                         jbd2_journal_put_journal_head(jh);
1079                 if (try_to_free)
1080                         release_buffer_page(bh);        /* Drops bh reference */
1081                 else
1082                         __brelse(bh);
1083                 cond_resched_lock(&journal->j_list_lock);
1084         }
1085         spin_unlock(&journal->j_list_lock);
1086         /*
1087          * This is a bit sleazy.  We use j_list_lock to protect transition
1088          * of a transaction into T_FINISHED state and calling
1089          * __jbd2_journal_drop_transaction(). Otherwise we could race with
1090          * other checkpointing code processing the transaction...
1091          */
1092         write_lock(&journal->j_state_lock);
1093         spin_lock(&journal->j_list_lock);
1094         /*
1095          * Now recheck if some buffers did not get attached to the transaction
1096          * while the lock was dropped...
1097          */
1098         if (commit_transaction->t_forget) {
1099                 spin_unlock(&journal->j_list_lock);
1100                 write_unlock(&journal->j_state_lock);
1101                 goto restart_loop;
1102         }
1103
1104         /* Add the transaction to the checkpoint list
1105          * __journal_remove_checkpoint() can not destroy transaction
1106          * under us because it is not marked as T_FINISHED yet */
1107         if (journal->j_checkpoint_transactions == NULL) {
1108                 journal->j_checkpoint_transactions = commit_transaction;
1109                 commit_transaction->t_cpnext = commit_transaction;
1110                 commit_transaction->t_cpprev = commit_transaction;
1111         } else {
1112                 commit_transaction->t_cpnext =
1113                         journal->j_checkpoint_transactions;
1114                 commit_transaction->t_cpprev =
1115                         commit_transaction->t_cpnext->t_cpprev;
1116                 commit_transaction->t_cpnext->t_cpprev =
1117                         commit_transaction;
1118                 commit_transaction->t_cpprev->t_cpnext =
1119                                 commit_transaction;
1120         }
1121         spin_unlock(&journal->j_list_lock);
1122
1123         /* Done with this transaction! */
1124
1125         jbd2_debug(3, "JBD2: commit phase 7\n");
1126
1127         J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1128
1129         commit_transaction->t_start = jiffies;
1130         stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1131                                               commit_transaction->t_start);
1132
1133         /*
1134          * File the transaction statistics
1135          */
1136         stats.ts_tid = commit_transaction->t_tid;
1137         stats.run.rs_handle_count =
1138                 atomic_read(&commit_transaction->t_handle_count);
1139         trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1140                              commit_transaction->t_tid, &stats.run);
1141         stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1142
1143         commit_transaction->t_state = T_COMMIT_CALLBACK;
1144         J_ASSERT(commit_transaction == journal->j_committing_transaction);
1145         journal->j_commit_sequence = commit_transaction->t_tid;
1146         journal->j_committing_transaction = NULL;
1147         commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1148
1149         /*
1150          * weight the commit time higher than the average time so we don't
1151          * react too strongly to vast changes in the commit time
1152          */
1153         if (likely(journal->j_average_commit_time))
1154                 journal->j_average_commit_time = (commit_time +
1155                                 journal->j_average_commit_time*3) / 4;
1156         else
1157                 journal->j_average_commit_time = commit_time;
1158
1159         write_unlock(&journal->j_state_lock);
1160
1161         if (journal->j_commit_callback)
1162                 journal->j_commit_callback(journal, commit_transaction);
1163         if (journal->j_fc_cleanup_callback)
1164                 journal->j_fc_cleanup_callback(journal, 1, commit_transaction->t_tid);
1165
1166         trace_jbd2_end_commit(journal, commit_transaction);
1167         jbd2_debug(1, "JBD2: commit %d complete, head %d\n",
1168                   journal->j_commit_sequence, journal->j_tail_sequence);
1169
1170         write_lock(&journal->j_state_lock);
1171         journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1172         journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1173         spin_lock(&journal->j_list_lock);
1174         commit_transaction->t_state = T_FINISHED;
1175         /* Check if the transaction can be dropped now that we are finished */
1176         if (commit_transaction->t_checkpoint_list == NULL &&
1177             commit_transaction->t_checkpoint_io_list == NULL) {
1178                 __jbd2_journal_drop_transaction(journal, commit_transaction);
1179                 jbd2_journal_free_transaction(commit_transaction);
1180         }
1181         spin_unlock(&journal->j_list_lock);
1182         write_unlock(&journal->j_state_lock);
1183         wake_up(&journal->j_wait_done_commit);
1184         wake_up(&journal->j_fc_wait);
1185
1186         /*
1187          * Calculate overall stats
1188          */
1189         spin_lock(&journal->j_history_lock);
1190         journal->j_stats.ts_tid++;
1191         journal->j_stats.ts_requested += stats.ts_requested;
1192         journal->j_stats.run.rs_wait += stats.run.rs_wait;
1193         journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1194         journal->j_stats.run.rs_running += stats.run.rs_running;
1195         journal->j_stats.run.rs_locked += stats.run.rs_locked;
1196         journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1197         journal->j_stats.run.rs_logging += stats.run.rs_logging;
1198         journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1199         journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1200         journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1201         spin_unlock(&journal->j_history_lock);
1202 }