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 */
journal_end_buffer_io_sync(struct buffer_head * bh,int uptodate)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 */
release_buffer_page(struct buffer_head * bh)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
jbd2_commit_block_csum_set(journal_t * j,struct buffer_head * bh)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 */
journal_submit_commit_record(journal_t * journal,transaction_t * commit_transaction,struct buffer_head ** cbh,__u32 crc32_sum)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,
159 REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh);
160 else
161 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
162
163 *cbh = bh;
164 return ret;
165 }
166
167 /*
168 * This function along with journal_submit_commit_record
169 * allows to write the commit record asynchronously.
170 */
journal_wait_on_commit_record(journal_t * journal,struct buffer_head * bh)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 */
jbd2_journal_submit_inode_data_buffers(struct jbd2_inode * jinode)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 */
jbd2_submit_inode_data(struct jbd2_inode * jinode)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
jbd2_wait_inode_data(journal_t * journal,struct jbd2_inode * jinode)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 */
journal_submit_data_buffers(journal_t * journal,transaction_t * commit_transaction)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
jbd2_journal_finish_inode_data_buffers(struct jbd2_inode * jinode)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 */
journal_finish_inode_data_buffers(journal_t * journal,transaction_t * commit_transaction)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
jbd2_checksum_data(__u32 crc32_sum,struct buffer_head * bh)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
write_tag_block(journal_t * j,journal_block_tag_t * tag,unsigned long long block)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
jbd2_block_tag_csum_set(journal_t * j,journal_block_tag_t * tag,struct buffer_head * bh,__u32 sequence)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 */
jbd2_journal_commit_transaction(journal_t * journal)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 jbd_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 jbd_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 jbd_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 jbd_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 jbd_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 jbd_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 jbd_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 jbd_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 jbd_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 jbd_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 jbd_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 jbd_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 jbd_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 jbd_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 jbd_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 }
1203