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 struct timespec64 now;
126 blk_opf_t write_flags = REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS;
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 write_flags |= REQ_PREFLUSH | REQ_FUA;
159
160 submit_bh(write_flags, bh);
161 *cbh = bh;
162 return 0;
163 }
164
165 /*
166 * This function along with journal_submit_commit_record
167 * allows to write the commit record asynchronously.
168 */
journal_wait_on_commit_record(journal_t * journal,struct buffer_head * bh)169 static int journal_wait_on_commit_record(journal_t *journal,
170 struct buffer_head *bh)
171 {
172 int ret = 0;
173
174 clear_buffer_dirty(bh);
175 wait_on_buffer(bh);
176
177 if (unlikely(!buffer_uptodate(bh)))
178 ret = -EIO;
179 put_bh(bh); /* One for getblk() */
180
181 return ret;
182 }
183
184 /*
185 * write the filemap data using writepage() address_space_operations.
186 * We don't do block allocation here even for delalloc. We don't
187 * use writepages() because with delayed allocation we may be doing
188 * block allocation in writepages().
189 */
jbd2_journal_submit_inode_data_buffers(struct jbd2_inode * jinode)190 int jbd2_journal_submit_inode_data_buffers(struct jbd2_inode *jinode)
191 {
192 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
193 struct writeback_control wbc = {
194 .sync_mode = WB_SYNC_ALL,
195 .nr_to_write = mapping->nrpages * 2,
196 .range_start = jinode->i_dirty_start,
197 .range_end = jinode->i_dirty_end,
198 };
199
200 /*
201 * submit the inode data buffers. We use writepage
202 * instead of writepages. Because writepages can do
203 * block allocation with delalloc. We need to write
204 * only allocated blocks here.
205 */
206 return generic_writepages(mapping, &wbc);
207 }
208
209 /* Send all the data buffers related to an inode */
jbd2_submit_inode_data(struct jbd2_inode * jinode)210 int jbd2_submit_inode_data(struct jbd2_inode *jinode)
211 {
212
213 if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
214 return 0;
215
216 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
217 return jbd2_journal_submit_inode_data_buffers(jinode);
218
219 }
220 EXPORT_SYMBOL(jbd2_submit_inode_data);
221
jbd2_wait_inode_data(journal_t * journal,struct jbd2_inode * jinode)222 int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
223 {
224 if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
225 !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
226 return 0;
227 return filemap_fdatawait_range_keep_errors(
228 jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
229 jinode->i_dirty_end);
230 }
231 EXPORT_SYMBOL(jbd2_wait_inode_data);
232
233 /*
234 * Submit all the data buffers of inode associated with the transaction to
235 * disk.
236 *
237 * We are in a committing transaction. Therefore no new inode can be added to
238 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
239 * operate on from being released while we write out pages.
240 */
journal_submit_data_buffers(journal_t * journal,transaction_t * commit_transaction)241 static int journal_submit_data_buffers(journal_t *journal,
242 transaction_t *commit_transaction)
243 {
244 struct jbd2_inode *jinode;
245 int err, ret = 0;
246
247 spin_lock(&journal->j_list_lock);
248 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
249 if (!(jinode->i_flags & JI_WRITE_DATA))
250 continue;
251 jinode->i_flags |= JI_COMMIT_RUNNING;
252 spin_unlock(&journal->j_list_lock);
253 /* submit the inode data buffers. */
254 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
255 if (journal->j_submit_inode_data_buffers) {
256 err = journal->j_submit_inode_data_buffers(jinode);
257 if (!ret)
258 ret = err;
259 }
260 spin_lock(&journal->j_list_lock);
261 J_ASSERT(jinode->i_transaction == commit_transaction);
262 jinode->i_flags &= ~JI_COMMIT_RUNNING;
263 smp_mb();
264 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
265 }
266 spin_unlock(&journal->j_list_lock);
267 return ret;
268 }
269
jbd2_journal_finish_inode_data_buffers(struct jbd2_inode * jinode)270 int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
271 {
272 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
273
274 return filemap_fdatawait_range_keep_errors(mapping,
275 jinode->i_dirty_start,
276 jinode->i_dirty_end);
277 }
278
279 /*
280 * Wait for data submitted for writeout, refile inodes to proper
281 * transaction if needed.
282 *
283 */
journal_finish_inode_data_buffers(journal_t * journal,transaction_t * commit_transaction)284 static int journal_finish_inode_data_buffers(journal_t *journal,
285 transaction_t *commit_transaction)
286 {
287 struct jbd2_inode *jinode, *next_i;
288 int err, ret = 0;
289
290 /* For locking, see the comment in journal_submit_data_buffers() */
291 spin_lock(&journal->j_list_lock);
292 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
293 if (!(jinode->i_flags & JI_WAIT_DATA))
294 continue;
295 jinode->i_flags |= JI_COMMIT_RUNNING;
296 spin_unlock(&journal->j_list_lock);
297 /* wait for the inode data buffers writeout. */
298 if (journal->j_finish_inode_data_buffers) {
299 err = journal->j_finish_inode_data_buffers(jinode);
300 if (!ret)
301 ret = err;
302 }
303 cond_resched();
304 spin_lock(&journal->j_list_lock);
305 jinode->i_flags &= ~JI_COMMIT_RUNNING;
306 smp_mb();
307 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
308 }
309
310 /* Now refile inode to proper lists */
311 list_for_each_entry_safe(jinode, next_i,
312 &commit_transaction->t_inode_list, i_list) {
313 list_del(&jinode->i_list);
314 if (jinode->i_next_transaction) {
315 jinode->i_transaction = jinode->i_next_transaction;
316 jinode->i_next_transaction = NULL;
317 list_add(&jinode->i_list,
318 &jinode->i_transaction->t_inode_list);
319 } else {
320 jinode->i_transaction = NULL;
321 jinode->i_dirty_start = 0;
322 jinode->i_dirty_end = 0;
323 }
324 }
325 spin_unlock(&journal->j_list_lock);
326
327 return ret;
328 }
329
jbd2_checksum_data(__u32 crc32_sum,struct buffer_head * bh)330 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
331 {
332 struct page *page = bh->b_page;
333 char *addr;
334 __u32 checksum;
335
336 addr = kmap_atomic(page);
337 checksum = crc32_be(crc32_sum,
338 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
339 kunmap_atomic(addr);
340
341 return checksum;
342 }
343
write_tag_block(journal_t * j,journal_block_tag_t * tag,unsigned long long block)344 static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
345 unsigned long long block)
346 {
347 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
348 if (jbd2_has_feature_64bit(j))
349 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
350 }
351
jbd2_block_tag_csum_set(journal_t * j,journal_block_tag_t * tag,struct buffer_head * bh,__u32 sequence)352 static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
353 struct buffer_head *bh, __u32 sequence)
354 {
355 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
356 struct page *page = bh->b_page;
357 __u8 *addr;
358 __u32 csum32;
359 __be32 seq;
360
361 if (!jbd2_journal_has_csum_v2or3(j))
362 return;
363
364 seq = cpu_to_be32(sequence);
365 addr = kmap_atomic(page);
366 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
367 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
368 bh->b_size);
369 kunmap_atomic(addr);
370
371 if (jbd2_has_feature_csum3(j))
372 tag3->t_checksum = cpu_to_be32(csum32);
373 else
374 tag->t_checksum = cpu_to_be16(csum32);
375 }
376 /*
377 * jbd2_journal_commit_transaction
378 *
379 * The primary function for committing a transaction to the log. This
380 * function is called by the journal thread to begin a complete commit.
381 */
jbd2_journal_commit_transaction(journal_t * journal)382 void jbd2_journal_commit_transaction(journal_t *journal)
383 {
384 struct transaction_stats_s stats;
385 transaction_t *commit_transaction;
386 struct journal_head *jh;
387 struct buffer_head *descriptor;
388 struct buffer_head **wbuf = journal->j_wbuf;
389 int bufs;
390 int flags;
391 int err;
392 unsigned long long blocknr;
393 ktime_t start_time;
394 u64 commit_time;
395 char *tagp = NULL;
396 journal_block_tag_t *tag = NULL;
397 int space_left = 0;
398 int first_tag = 0;
399 int tag_flag;
400 int i;
401 int tag_bytes = journal_tag_bytes(journal);
402 struct buffer_head *cbh = NULL; /* For transactional checksums */
403 __u32 crc32_sum = ~0;
404 struct blk_plug plug;
405 /* Tail of the journal */
406 unsigned long first_block;
407 tid_t first_tid;
408 int update_tail;
409 int csum_size = 0;
410 LIST_HEAD(io_bufs);
411 LIST_HEAD(log_bufs);
412
413 if (jbd2_journal_has_csum_v2or3(journal))
414 csum_size = sizeof(struct jbd2_journal_block_tail);
415
416 /*
417 * First job: lock down the current transaction and wait for
418 * all outstanding updates to complete.
419 */
420
421 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
422 if (journal->j_flags & JBD2_FLUSHED) {
423 jbd2_debug(3, "super block updated\n");
424 mutex_lock_io(&journal->j_checkpoint_mutex);
425 /*
426 * We hold j_checkpoint_mutex so tail cannot change under us.
427 * We don't need any special data guarantees for writing sb
428 * since journal is empty and it is ok for write to be
429 * flushed only with transaction commit.
430 */
431 jbd2_journal_update_sb_log_tail(journal,
432 journal->j_tail_sequence,
433 journal->j_tail, 0);
434 mutex_unlock(&journal->j_checkpoint_mutex);
435 } else {
436 jbd2_debug(3, "superblock not updated\n");
437 }
438
439 J_ASSERT(journal->j_running_transaction != NULL);
440 J_ASSERT(journal->j_committing_transaction == NULL);
441
442 write_lock(&journal->j_state_lock);
443 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
444 while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
445 DEFINE_WAIT(wait);
446
447 prepare_to_wait(&journal->j_fc_wait, &wait,
448 TASK_UNINTERRUPTIBLE);
449 write_unlock(&journal->j_state_lock);
450 schedule();
451 write_lock(&journal->j_state_lock);
452 finish_wait(&journal->j_fc_wait, &wait);
453 /*
454 * TODO: by blocking fast commits here, we are increasing
455 * fsync() latency slightly. Strictly speaking, we don't need
456 * to block fast commits until the transaction enters T_FLUSH
457 * state. So an optimization is possible where we block new fast
458 * commits here and wait for existing ones to complete
459 * just before we enter T_FLUSH. That way, the existing fast
460 * commits and this full commit can proceed parallely.
461 */
462 }
463 write_unlock(&journal->j_state_lock);
464
465 commit_transaction = journal->j_running_transaction;
466
467 trace_jbd2_start_commit(journal, commit_transaction);
468 jbd2_debug(1, "JBD2: starting commit of transaction %d\n",
469 commit_transaction->t_tid);
470
471 write_lock(&journal->j_state_lock);
472 journal->j_fc_off = 0;
473 J_ASSERT(commit_transaction->t_state == T_RUNNING);
474 commit_transaction->t_state = T_LOCKED;
475
476 trace_jbd2_commit_locking(journal, commit_transaction);
477 stats.run.rs_wait = commit_transaction->t_max_wait;
478 stats.run.rs_request_delay = 0;
479 stats.run.rs_locked = jiffies;
480 if (commit_transaction->t_requested)
481 stats.run.rs_request_delay =
482 jbd2_time_diff(commit_transaction->t_requested,
483 stats.run.rs_locked);
484 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
485 stats.run.rs_locked);
486
487 // waits for any t_updates to finish
488 jbd2_journal_wait_updates(journal);
489
490 commit_transaction->t_state = T_SWITCH;
491
492 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
493 journal->j_max_transaction_buffers);
494
495 /*
496 * First thing we are allowed to do is to discard any remaining
497 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
498 * that there are no such buffers: if a large filesystem
499 * operation like a truncate needs to split itself over multiple
500 * transactions, then it may try to do a jbd2_journal_restart() while
501 * there are still BJ_Reserved buffers outstanding. These must
502 * be released cleanly from the current transaction.
503 *
504 * In this case, the filesystem must still reserve write access
505 * again before modifying the buffer in the new transaction, but
506 * we do not require it to remember exactly which old buffers it
507 * has reserved. This is consistent with the existing behaviour
508 * that multiple jbd2_journal_get_write_access() calls to the same
509 * buffer are perfectly permissible.
510 * We use journal->j_state_lock here to serialize processing of
511 * t_reserved_list with eviction of buffers from journal_unmap_buffer().
512 */
513 while (commit_transaction->t_reserved_list) {
514 jh = commit_transaction->t_reserved_list;
515 JBUFFER_TRACE(jh, "reserved, unused: refile");
516 /*
517 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
518 * leave undo-committed data.
519 */
520 if (jh->b_committed_data) {
521 struct buffer_head *bh = jh2bh(jh);
522
523 spin_lock(&jh->b_state_lock);
524 jbd2_free(jh->b_committed_data, bh->b_size);
525 jh->b_committed_data = NULL;
526 spin_unlock(&jh->b_state_lock);
527 }
528 jbd2_journal_refile_buffer(journal, jh);
529 }
530
531 write_unlock(&journal->j_state_lock);
532 /*
533 * Now try to drop any written-back buffers from the journal's
534 * checkpoint lists. We do this *before* commit because it potentially
535 * frees some memory
536 */
537 spin_lock(&journal->j_list_lock);
538 __jbd2_journal_clean_checkpoint_list(journal, false);
539 spin_unlock(&journal->j_list_lock);
540
541 jbd2_debug(3, "JBD2: commit phase 1\n");
542
543 /*
544 * Clear revoked flag to reflect there is no revoked buffers
545 * in the next transaction which is going to be started.
546 */
547 jbd2_clear_buffer_revoked_flags(journal);
548
549 /*
550 * Switch to a new revoke table.
551 */
552 jbd2_journal_switch_revoke_table(journal);
553
554 write_lock(&journal->j_state_lock);
555 /*
556 * Reserved credits cannot be claimed anymore, free them
557 */
558 atomic_sub(atomic_read(&journal->j_reserved_credits),
559 &commit_transaction->t_outstanding_credits);
560
561 trace_jbd2_commit_flushing(journal, commit_transaction);
562 stats.run.rs_flushing = jiffies;
563 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
564 stats.run.rs_flushing);
565
566 commit_transaction->t_state = T_FLUSH;
567 journal->j_committing_transaction = commit_transaction;
568 journal->j_running_transaction = NULL;
569 start_time = ktime_get();
570 commit_transaction->t_log_start = journal->j_head;
571 wake_up_all(&journal->j_wait_transaction_locked);
572 write_unlock(&journal->j_state_lock);
573
574 jbd2_debug(3, "JBD2: commit phase 2a\n");
575
576 /*
577 * Now start flushing things to disk, in the order they appear
578 * on the transaction lists. Data blocks go first.
579 */
580 err = journal_submit_data_buffers(journal, commit_transaction);
581 if (err)
582 jbd2_journal_abort(journal, err);
583
584 blk_start_plug(&plug);
585 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
586
587 jbd2_debug(3, "JBD2: commit phase 2b\n");
588
589 /*
590 * Way to go: we have now written out all of the data for a
591 * transaction! Now comes the tricky part: we need to write out
592 * metadata. Loop over the transaction's entire buffer list:
593 */
594 write_lock(&journal->j_state_lock);
595 commit_transaction->t_state = T_COMMIT;
596 write_unlock(&journal->j_state_lock);
597
598 trace_jbd2_commit_logging(journal, commit_transaction);
599 stats.run.rs_logging = jiffies;
600 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
601 stats.run.rs_logging);
602 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
603 stats.run.rs_blocks_logged = 0;
604
605 J_ASSERT(commit_transaction->t_nr_buffers <=
606 atomic_read(&commit_transaction->t_outstanding_credits));
607
608 err = 0;
609 bufs = 0;
610 descriptor = NULL;
611 while (commit_transaction->t_buffers) {
612
613 /* Find the next buffer to be journaled... */
614
615 jh = commit_transaction->t_buffers;
616
617 /* If we're in abort mode, we just un-journal the buffer and
618 release it. */
619
620 if (is_journal_aborted(journal)) {
621 clear_buffer_jbddirty(jh2bh(jh));
622 JBUFFER_TRACE(jh, "journal is aborting: refile");
623 jbd2_buffer_abort_trigger(jh,
624 jh->b_frozen_data ?
625 jh->b_frozen_triggers :
626 jh->b_triggers);
627 jbd2_journal_refile_buffer(journal, jh);
628 /* If that was the last one, we need to clean up
629 * any descriptor buffers which may have been
630 * already allocated, even if we are now
631 * aborting. */
632 if (!commit_transaction->t_buffers)
633 goto start_journal_io;
634 continue;
635 }
636
637 /* Make sure we have a descriptor block in which to
638 record the metadata buffer. */
639
640 if (!descriptor) {
641 J_ASSERT (bufs == 0);
642
643 jbd2_debug(4, "JBD2: get descriptor\n");
644
645 descriptor = jbd2_journal_get_descriptor_buffer(
646 commit_transaction,
647 JBD2_DESCRIPTOR_BLOCK);
648 if (!descriptor) {
649 jbd2_journal_abort(journal, -EIO);
650 continue;
651 }
652
653 jbd2_debug(4, "JBD2: got buffer %llu (%p)\n",
654 (unsigned long long)descriptor->b_blocknr,
655 descriptor->b_data);
656 tagp = &descriptor->b_data[sizeof(journal_header_t)];
657 space_left = descriptor->b_size -
658 sizeof(journal_header_t);
659 first_tag = 1;
660 set_buffer_jwrite(descriptor);
661 set_buffer_dirty(descriptor);
662 wbuf[bufs++] = descriptor;
663
664 /* Record it so that we can wait for IO
665 completion later */
666 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
667 jbd2_file_log_bh(&log_bufs, descriptor);
668 }
669
670 /* Where is the buffer to be written? */
671
672 err = jbd2_journal_next_log_block(journal, &blocknr);
673 /* If the block mapping failed, just abandon the buffer
674 and repeat this loop: we'll fall into the
675 refile-on-abort condition above. */
676 if (err) {
677 jbd2_journal_abort(journal, err);
678 continue;
679 }
680
681 /*
682 * start_this_handle() uses t_outstanding_credits to determine
683 * the free space in the log.
684 */
685 atomic_dec(&commit_transaction->t_outstanding_credits);
686
687 /* Bump b_count to prevent truncate from stumbling over
688 the shadowed buffer! @@@ This can go if we ever get
689 rid of the shadow pairing of buffers. */
690 atomic_inc(&jh2bh(jh)->b_count);
691
692 /*
693 * Make a temporary IO buffer with which to write it out
694 * (this will requeue the metadata buffer to BJ_Shadow).
695 */
696 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
697 JBUFFER_TRACE(jh, "ph3: write metadata");
698 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
699 jh, &wbuf[bufs], blocknr);
700 if (flags < 0) {
701 jbd2_journal_abort(journal, flags);
702 continue;
703 }
704 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
705
706 /* Record the new block's tag in the current descriptor
707 buffer */
708
709 tag_flag = 0;
710 if (flags & 1)
711 tag_flag |= JBD2_FLAG_ESCAPE;
712 if (!first_tag)
713 tag_flag |= JBD2_FLAG_SAME_UUID;
714
715 tag = (journal_block_tag_t *) tagp;
716 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
717 tag->t_flags = cpu_to_be16(tag_flag);
718 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
719 commit_transaction->t_tid);
720 tagp += tag_bytes;
721 space_left -= tag_bytes;
722 bufs++;
723
724 if (first_tag) {
725 memcpy (tagp, journal->j_uuid, 16);
726 tagp += 16;
727 space_left -= 16;
728 first_tag = 0;
729 }
730
731 /* If there's no more to do, or if the descriptor is full,
732 let the IO rip! */
733
734 if (bufs == journal->j_wbufsize ||
735 commit_transaction->t_buffers == NULL ||
736 space_left < tag_bytes + 16 + csum_size) {
737
738 jbd2_debug(4, "JBD2: Submit %d IOs\n", bufs);
739
740 /* Write an end-of-descriptor marker before
741 submitting the IOs. "tag" still points to
742 the last tag we set up. */
743
744 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
745 start_journal_io:
746 if (descriptor)
747 jbd2_descriptor_block_csum_set(journal,
748 descriptor);
749
750 for (i = 0; i < bufs; i++) {
751 struct buffer_head *bh = wbuf[i];
752
753 /*
754 * Compute checksum.
755 */
756 if (jbd2_has_feature_checksum(journal)) {
757 crc32_sum =
758 jbd2_checksum_data(crc32_sum, bh);
759 }
760
761 lock_buffer(bh);
762 clear_buffer_dirty(bh);
763 set_buffer_uptodate(bh);
764 bh->b_end_io = journal_end_buffer_io_sync;
765 submit_bh(REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS,
766 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 __jbd2_journal_drop_transaction(journal, commit_transaction);
1178 jbd2_journal_free_transaction(commit_transaction);
1179 }
1180 spin_unlock(&journal->j_list_lock);
1181 write_unlock(&journal->j_state_lock);
1182 wake_up(&journal->j_wait_done_commit);
1183 wake_up(&journal->j_fc_wait);
1184
1185 /*
1186 * Calculate overall stats
1187 */
1188 spin_lock(&journal->j_history_lock);
1189 journal->j_stats.ts_tid++;
1190 journal->j_stats.ts_requested += stats.ts_requested;
1191 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1192 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1193 journal->j_stats.run.rs_running += stats.run.rs_running;
1194 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1195 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1196 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1197 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1198 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1199 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1200 spin_unlock(&journal->j_history_lock);
1201 }
1202