~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/jbd2/commit.c

Version: ~ [ linux-5.10-rc1 ] ~ [ linux-5.9.1 ] ~ [ linux-5.8.16 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.72 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.152 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.202 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.240 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.240 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.85 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * linux/fs/jbd2/commit.c
  3  *
  4  * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
  5  *
  6  * Copyright 1998 Red Hat corp --- All Rights Reserved
  7  *
  8  * This file is part of the Linux kernel and is made available under
  9  * the terms of the GNU General Public License, version 2, or at your
 10  * option, any later version, incorporated herein by reference.
 11  *
 12  * Journal commit routines for the generic filesystem journaling code;
 13  * part of the ext2fs journaling system.
 14  */
 15 
 16 #include <linux/time.h>
 17 #include <linux/fs.h>
 18 #include <linux/jbd2.h>
 19 #include <linux/errno.h>
 20 #include <linux/slab.h>
 21 #include <linux/mm.h>
 22 #include <linux/pagemap.h>
 23 #include <linux/jiffies.h>
 24 #include <linux/crc32.h>
 25 #include <linux/writeback.h>
 26 #include <linux/backing-dev.h>
 27 #include <linux/bio.h>
 28 #include <linux/blkdev.h>
 29 #include <linux/bitops.h>
 30 #include <trace/events/jbd2.h>
 31 
 32 /*
 33  * IO end handler for temporary buffer_heads handling writes to the journal.
 34  */
 35 static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
 36 {
 37         struct buffer_head *orig_bh = bh->b_private;
 38 
 39         BUFFER_TRACE(bh, "");
 40         if (uptodate)
 41                 set_buffer_uptodate(bh);
 42         else
 43                 clear_buffer_uptodate(bh);
 44         if (orig_bh) {
 45                 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
 46                 smp_mb__after_atomic();
 47                 wake_up_bit(&orig_bh->b_state, BH_Shadow);
 48         }
 49         unlock_buffer(bh);
 50 }
 51 
 52 /*
 53  * When an ext4 file is truncated, it is possible that some pages are not
 54  * successfully freed, because they are attached to a committing transaction.
 55  * After the transaction commits, these pages are left on the LRU, with no
 56  * ->mapping, and with attached buffers.  These pages are trivially reclaimable
 57  * by the VM, but their apparent absence upsets the VM accounting, and it makes
 58  * the numbers in /proc/meminfo look odd.
 59  *
 60  * So here, we have a buffer which has just come off the forget list.  Look to
 61  * see if we can strip all buffers from the backing page.
 62  *
 63  * Called under lock_journal(), and possibly under journal_datalist_lock.  The
 64  * caller provided us with a ref against the buffer, and we drop that here.
 65  */
 66 static void release_buffer_page(struct buffer_head *bh)
 67 {
 68         struct page *page;
 69 
 70         if (buffer_dirty(bh))
 71                 goto nope;
 72         if (atomic_read(&bh->b_count) != 1)
 73                 goto nope;
 74         page = bh->b_page;
 75         if (!page)
 76                 goto nope;
 77         if (page->mapping)
 78                 goto nope;
 79 
 80         /* OK, it's a truncated page */
 81         if (!trylock_page(page))
 82                 goto nope;
 83 
 84         get_page(page);
 85         __brelse(bh);
 86         try_to_free_buffers(page);
 87         unlock_page(page);
 88         put_page(page);
 89         return;
 90 
 91 nope:
 92         __brelse(bh);
 93 }
 94 
 95 static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
 96 {
 97         struct commit_header *h;
 98         __u32 csum;
 99 
100         if (!jbd2_journal_has_csum_v2or3(j))
101                 return;
102 
103         h = (struct commit_header *)(bh->b_data);
104         h->h_chksum_type = 0;
105         h->h_chksum_size = 0;
106         h->h_chksum[0] = 0;
107         csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
108         h->h_chksum[0] = cpu_to_be32(csum);
109 }
110 
111 /*
112  * Done it all: now submit the commit record.  We should have
113  * cleaned up our previous buffers by now, so if we are in abort
114  * mode we can now just skip the rest of the journal write
115  * entirely.
116  *
117  * Returns 1 if the journal needs to be aborted or 0 on success
118  */
119 static int journal_submit_commit_record(journal_t *journal,
120                                         transaction_t *commit_transaction,
121                                         struct buffer_head **cbh,
122                                         __u32 crc32_sum)
123 {
124         struct commit_header *tmp;
125         struct buffer_head *bh;
126         int ret;
127         struct timespec64 now = current_kernel_time64();
128 
129         *cbh = NULL;
130 
131         if (is_journal_aborted(journal))
132                 return 0;
133 
134         bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
135                                                 JBD2_COMMIT_BLOCK);
136         if (!bh)
137                 return 1;
138 
139         tmp = (struct commit_header *)bh->b_data;
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  */
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 dealyed allocation we may be doing
190  * block allocation in writepages().
191  */
192 static int journal_submit_inode_data_buffers(struct address_space *mapping)
193 {
194         int ret;
195         struct writeback_control wbc = {
196                 .sync_mode =  WB_SYNC_ALL,
197                 .nr_to_write = mapping->nrpages * 2,
198                 .range_start = 0,
199                 .range_end = i_size_read(mapping->host),
200         };
201 
202         ret = generic_writepages(mapping, &wbc);
203         return ret;
204 }
205 
206 /*
207  * Submit all the data buffers of inode associated with the transaction to
208  * disk.
209  *
210  * We are in a committing transaction. Therefore no new inode can be added to
211  * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
212  * operate on from being released while we write out pages.
213  */
214 static int journal_submit_data_buffers(journal_t *journal,
215                 transaction_t *commit_transaction)
216 {
217         struct jbd2_inode *jinode;
218         int err, ret = 0;
219         struct address_space *mapping;
220 
221         spin_lock(&journal->j_list_lock);
222         list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
223                 if (!(jinode->i_flags & JI_WRITE_DATA))
224                         continue;
225                 mapping = jinode->i_vfs_inode->i_mapping;
226                 jinode->i_flags |= JI_COMMIT_RUNNING;
227                 spin_unlock(&journal->j_list_lock);
228                 /*
229                  * submit the inode data buffers. We use writepage
230                  * instead of writepages. Because writepages can do
231                  * block allocation  with delalloc. We need to write
232                  * only allocated blocks here.
233                  */
234                 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
235                 err = journal_submit_inode_data_buffers(mapping);
236                 if (!ret)
237                         ret = err;
238                 spin_lock(&journal->j_list_lock);
239                 J_ASSERT(jinode->i_transaction == commit_transaction);
240                 jinode->i_flags &= ~JI_COMMIT_RUNNING;
241                 smp_mb();
242                 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
243         }
244         spin_unlock(&journal->j_list_lock);
245         return ret;
246 }
247 
248 /*
249  * Wait for data submitted for writeout, refile inodes to proper
250  * transaction if needed.
251  *
252  */
253 static int journal_finish_inode_data_buffers(journal_t *journal,
254                 transaction_t *commit_transaction)
255 {
256         struct jbd2_inode *jinode, *next_i;
257         int err, ret = 0;
258 
259         /* For locking, see the comment in journal_submit_data_buffers() */
260         spin_lock(&journal->j_list_lock);
261         list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
262                 if (!(jinode->i_flags & JI_WAIT_DATA))
263                         continue;
264                 jinode->i_flags |= JI_COMMIT_RUNNING;
265                 spin_unlock(&journal->j_list_lock);
266                 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
267                 if (err) {
268                         /*
269                          * Because AS_EIO is cleared by
270                          * filemap_fdatawait_range(), set it again so
271                          * that user process can get -EIO from fsync().
272                          */
273                         mapping_set_error(jinode->i_vfs_inode->i_mapping, -EIO);
274 
275                         if (!ret)
276                                 ret = err;
277                 }
278                 spin_lock(&journal->j_list_lock);
279                 jinode->i_flags &= ~JI_COMMIT_RUNNING;
280                 smp_mb();
281                 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
282         }
283 
284         /* Now refile inode to proper lists */
285         list_for_each_entry_safe(jinode, next_i,
286                                  &commit_transaction->t_inode_list, i_list) {
287                 list_del(&jinode->i_list);
288                 if (jinode->i_next_transaction) {
289                         jinode->i_transaction = jinode->i_next_transaction;
290                         jinode->i_next_transaction = NULL;
291                         list_add(&jinode->i_list,
292                                 &jinode->i_transaction->t_inode_list);
293                 } else {
294                         jinode->i_transaction = NULL;
295                 }
296         }
297         spin_unlock(&journal->j_list_lock);
298 
299         return ret;
300 }
301 
302 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
303 {
304         struct page *page = bh->b_page;
305         char *addr;
306         __u32 checksum;
307 
308         addr = kmap_atomic(page);
309         checksum = crc32_be(crc32_sum,
310                 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
311         kunmap_atomic(addr);
312 
313         return checksum;
314 }
315 
316 static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
317                                    unsigned long long block)
318 {
319         tag->t_blocknr = cpu_to_be32(block & (u32)~0);
320         if (jbd2_has_feature_64bit(j))
321                 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
322 }
323 
324 static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
325                                     struct buffer_head *bh, __u32 sequence)
326 {
327         journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
328         struct page *page = bh->b_page;
329         __u8 *addr;
330         __u32 csum32;
331         __be32 seq;
332 
333         if (!jbd2_journal_has_csum_v2or3(j))
334                 return;
335 
336         seq = cpu_to_be32(sequence);
337         addr = kmap_atomic(page);
338         csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
339         csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
340                              bh->b_size);
341         kunmap_atomic(addr);
342 
343         if (jbd2_has_feature_csum3(j))
344                 tag3->t_checksum = cpu_to_be32(csum32);
345         else
346                 tag->t_checksum = cpu_to_be16(csum32);
347 }
348 /*
349  * jbd2_journal_commit_transaction
350  *
351  * The primary function for committing a transaction to the log.  This
352  * function is called by the journal thread to begin a complete commit.
353  */
354 void jbd2_journal_commit_transaction(journal_t *journal)
355 {
356         struct transaction_stats_s stats;
357         transaction_t *commit_transaction;
358         struct journal_head *jh;
359         struct buffer_head *descriptor;
360         struct buffer_head **wbuf = journal->j_wbuf;
361         int bufs;
362         int flags;
363         int err;
364         unsigned long long blocknr;
365         ktime_t start_time;
366         u64 commit_time;
367         char *tagp = NULL;
368         journal_block_tag_t *tag = NULL;
369         int space_left = 0;
370         int first_tag = 0;
371         int tag_flag;
372         int i;
373         int tag_bytes = journal_tag_bytes(journal);
374         struct buffer_head *cbh = NULL; /* For transactional checksums */
375         __u32 crc32_sum = ~0;
376         struct blk_plug plug;
377         /* Tail of the journal */
378         unsigned long first_block;
379         tid_t first_tid;
380         int update_tail;
381         int csum_size = 0;
382         LIST_HEAD(io_bufs);
383         LIST_HEAD(log_bufs);
384 
385         if (jbd2_journal_has_csum_v2or3(journal))
386                 csum_size = sizeof(struct jbd2_journal_block_tail);
387 
388         /*
389          * First job: lock down the current transaction and wait for
390          * all outstanding updates to complete.
391          */
392 
393         /* Do we need to erase the effects of a prior jbd2_journal_flush? */
394         if (journal->j_flags & JBD2_FLUSHED) {
395                 jbd_debug(3, "super block updated\n");
396                 mutex_lock(&journal->j_checkpoint_mutex);
397                 /*
398                  * We hold j_checkpoint_mutex so tail cannot change under us.
399                  * We don't need any special data guarantees for writing sb
400                  * since journal is empty and it is ok for write to be
401                  * flushed only with transaction commit.
402                  */
403                 jbd2_journal_update_sb_log_tail(journal,
404                                                 journal->j_tail_sequence,
405                                                 journal->j_tail,
406                                                 REQ_SYNC);
407                 mutex_unlock(&journal->j_checkpoint_mutex);
408         } else {
409                 jbd_debug(3, "superblock not updated\n");
410         }
411 
412         J_ASSERT(journal->j_running_transaction != NULL);
413         J_ASSERT(journal->j_committing_transaction == NULL);
414 
415         commit_transaction = journal->j_running_transaction;
416 
417         trace_jbd2_start_commit(journal, commit_transaction);
418         jbd_debug(1, "JBD2: starting commit of transaction %d\n",
419                         commit_transaction->t_tid);
420 
421         write_lock(&journal->j_state_lock);
422         J_ASSERT(commit_transaction->t_state == T_RUNNING);
423         commit_transaction->t_state = T_LOCKED;
424 
425         trace_jbd2_commit_locking(journal, commit_transaction);
426         stats.run.rs_wait = commit_transaction->t_max_wait;
427         stats.run.rs_request_delay = 0;
428         stats.run.rs_locked = jiffies;
429         if (commit_transaction->t_requested)
430                 stats.run.rs_request_delay =
431                         jbd2_time_diff(commit_transaction->t_requested,
432                                        stats.run.rs_locked);
433         stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
434                                               stats.run.rs_locked);
435 
436         spin_lock(&commit_transaction->t_handle_lock);
437         while (atomic_read(&commit_transaction->t_updates)) {
438                 DEFINE_WAIT(wait);
439 
440                 prepare_to_wait(&journal->j_wait_updates, &wait,
441                                         TASK_UNINTERRUPTIBLE);
442                 if (atomic_read(&commit_transaction->t_updates)) {
443                         spin_unlock(&commit_transaction->t_handle_lock);
444                         write_unlock(&journal->j_state_lock);
445                         schedule();
446                         write_lock(&journal->j_state_lock);
447                         spin_lock(&commit_transaction->t_handle_lock);
448                 }
449                 finish_wait(&journal->j_wait_updates, &wait);
450         }
451         spin_unlock(&commit_transaction->t_handle_lock);
452 
453         J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
454                         journal->j_max_transaction_buffers);
455 
456         /*
457          * First thing we are allowed to do is to discard any remaining
458          * BJ_Reserved buffers.  Note, it is _not_ permissible to assume
459          * that there are no such buffers: if a large filesystem
460          * operation like a truncate needs to split itself over multiple
461          * transactions, then it may try to do a jbd2_journal_restart() while
462          * there are still BJ_Reserved buffers outstanding.  These must
463          * be released cleanly from the current transaction.
464          *
465          * In this case, the filesystem must still reserve write access
466          * again before modifying the buffer in the new transaction, but
467          * we do not require it to remember exactly which old buffers it
468          * has reserved.  This is consistent with the existing behaviour
469          * that multiple jbd2_journal_get_write_access() calls to the same
470          * buffer are perfectly permissible.
471          */
472         while (commit_transaction->t_reserved_list) {
473                 jh = commit_transaction->t_reserved_list;
474                 JBUFFER_TRACE(jh, "reserved, unused: refile");
475                 /*
476                  * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
477                  * leave undo-committed data.
478                  */
479                 if (jh->b_committed_data) {
480                         struct buffer_head *bh = jh2bh(jh);
481 
482                         jbd_lock_bh_state(bh);
483                         jbd2_free(jh->b_committed_data, bh->b_size);
484                         jh->b_committed_data = NULL;
485                         jbd_unlock_bh_state(bh);
486                 }
487                 jbd2_journal_refile_buffer(journal, jh);
488         }
489 
490         /*
491          * Now try to drop any written-back buffers from the journal's
492          * checkpoint lists.  We do this *before* commit because it potentially
493          * frees some memory
494          */
495         spin_lock(&journal->j_list_lock);
496         __jbd2_journal_clean_checkpoint_list(journal, false);
497         spin_unlock(&journal->j_list_lock);
498 
499         jbd_debug(3, "JBD2: commit phase 1\n");
500 
501         /*
502          * Clear revoked flag to reflect there is no revoked buffers
503          * in the next transaction which is going to be started.
504          */
505         jbd2_clear_buffer_revoked_flags(journal);
506 
507         /*
508          * Switch to a new revoke table.
509          */
510         jbd2_journal_switch_revoke_table(journal);
511 
512         /*
513          * Reserved credits cannot be claimed anymore, free them
514          */
515         atomic_sub(atomic_read(&journal->j_reserved_credits),
516                    &commit_transaction->t_outstanding_credits);
517 
518         trace_jbd2_commit_flushing(journal, commit_transaction);
519         stats.run.rs_flushing = jiffies;
520         stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
521                                              stats.run.rs_flushing);
522 
523         commit_transaction->t_state = T_FLUSH;
524         journal->j_committing_transaction = commit_transaction;
525         journal->j_running_transaction = NULL;
526         start_time = ktime_get();
527         commit_transaction->t_log_start = journal->j_head;
528         wake_up(&journal->j_wait_transaction_locked);
529         write_unlock(&journal->j_state_lock);
530 
531         jbd_debug(3, "JBD2: commit phase 2a\n");
532 
533         /*
534          * Now start flushing things to disk, in the order they appear
535          * on the transaction lists.  Data blocks go first.
536          */
537         err = journal_submit_data_buffers(journal, commit_transaction);
538         if (err)
539                 jbd2_journal_abort(journal, err);
540 
541         blk_start_plug(&plug);
542         jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
543 
544         jbd_debug(3, "JBD2: commit phase 2b\n");
545 
546         /*
547          * Way to go: we have now written out all of the data for a
548          * transaction!  Now comes the tricky part: we need to write out
549          * metadata.  Loop over the transaction's entire buffer list:
550          */
551         write_lock(&journal->j_state_lock);
552         commit_transaction->t_state = T_COMMIT;
553         write_unlock(&journal->j_state_lock);
554 
555         trace_jbd2_commit_logging(journal, commit_transaction);
556         stats.run.rs_logging = jiffies;
557         stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
558                                                stats.run.rs_logging);
559         stats.run.rs_blocks =
560                 atomic_read(&commit_transaction->t_outstanding_credits);
561         stats.run.rs_blocks_logged = 0;
562 
563         J_ASSERT(commit_transaction->t_nr_buffers <=
564                  atomic_read(&commit_transaction->t_outstanding_credits));
565 
566         err = 0;
567         bufs = 0;
568         descriptor = NULL;
569         while (commit_transaction->t_buffers) {
570 
571                 /* Find the next buffer to be journaled... */
572 
573                 jh = commit_transaction->t_buffers;
574 
575                 /* If we're in abort mode, we just un-journal the buffer and
576                    release it. */
577 
578                 if (is_journal_aborted(journal)) {
579                         clear_buffer_jbddirty(jh2bh(jh));
580                         JBUFFER_TRACE(jh, "journal is aborting: refile");
581                         jbd2_buffer_abort_trigger(jh,
582                                                   jh->b_frozen_data ?
583                                                   jh->b_frozen_triggers :
584                                                   jh->b_triggers);
585                         jbd2_journal_refile_buffer(journal, jh);
586                         /* If that was the last one, we need to clean up
587                          * any descriptor buffers which may have been
588                          * already allocated, even if we are now
589                          * aborting. */
590                         if (!commit_transaction->t_buffers)
591                                 goto start_journal_io;
592                         continue;
593                 }
594 
595                 /* Make sure we have a descriptor block in which to
596                    record the metadata buffer. */
597 
598                 if (!descriptor) {
599                         J_ASSERT (bufs == 0);
600 
601                         jbd_debug(4, "JBD2: get descriptor\n");
602 
603                         descriptor = jbd2_journal_get_descriptor_buffer(
604                                                         commit_transaction,
605                                                         JBD2_DESCRIPTOR_BLOCK);
606                         if (!descriptor) {
607                                 jbd2_journal_abort(journal, -EIO);
608                                 continue;
609                         }
610 
611                         jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
612                                 (unsigned long long)descriptor->b_blocknr,
613                                 descriptor->b_data);
614                         tagp = &descriptor->b_data[sizeof(journal_header_t)];
615                         space_left = descriptor->b_size -
616                                                 sizeof(journal_header_t);
617                         first_tag = 1;
618                         set_buffer_jwrite(descriptor);
619                         set_buffer_dirty(descriptor);
620                         wbuf[bufs++] = descriptor;
621 
622                         /* Record it so that we can wait for IO
623                            completion later */
624                         BUFFER_TRACE(descriptor, "ph3: file as descriptor");
625                         jbd2_file_log_bh(&log_bufs, descriptor);
626                 }
627 
628                 /* Where is the buffer to be written? */
629 
630                 err = jbd2_journal_next_log_block(journal, &blocknr);
631                 /* If the block mapping failed, just abandon the buffer
632                    and repeat this loop: we'll fall into the
633                    refile-on-abort condition above. */
634                 if (err) {
635                         jbd2_journal_abort(journal, err);
636                         continue;
637                 }
638 
639                 /*
640                  * start_this_handle() uses t_outstanding_credits to determine
641                  * the free space in the log, but this counter is changed
642                  * by jbd2_journal_next_log_block() also.
643                  */
644                 atomic_dec(&commit_transaction->t_outstanding_credits);
645 
646                 /* Bump b_count to prevent truncate from stumbling over
647                    the shadowed buffer!  @@@ This can go if we ever get
648                    rid of the shadow pairing of buffers. */
649                 atomic_inc(&jh2bh(jh)->b_count);
650 
651                 /*
652                  * Make a temporary IO buffer with which to write it out
653                  * (this will requeue the metadata buffer to BJ_Shadow).
654                  */
655                 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
656                 JBUFFER_TRACE(jh, "ph3: write metadata");
657                 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
658                                                 jh, &wbuf[bufs], blocknr);
659                 if (flags < 0) {
660                         jbd2_journal_abort(journal, flags);
661                         continue;
662                 }
663                 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
664 
665                 /* Record the new block's tag in the current descriptor
666                    buffer */
667 
668                 tag_flag = 0;
669                 if (flags & 1)
670                         tag_flag |= JBD2_FLAG_ESCAPE;
671                 if (!first_tag)
672                         tag_flag |= JBD2_FLAG_SAME_UUID;
673 
674                 tag = (journal_block_tag_t *) tagp;
675                 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
676                 tag->t_flags = cpu_to_be16(tag_flag);
677                 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
678                                         commit_transaction->t_tid);
679                 tagp += tag_bytes;
680                 space_left -= tag_bytes;
681                 bufs++;
682 
683                 if (first_tag) {
684                         memcpy (tagp, journal->j_uuid, 16);
685                         tagp += 16;
686                         space_left -= 16;
687                         first_tag = 0;
688                 }
689 
690                 /* If there's no more to do, or if the descriptor is full,
691                    let the IO rip! */
692 
693                 if (bufs == journal->j_wbufsize ||
694                     commit_transaction->t_buffers == NULL ||
695                     space_left < tag_bytes + 16 + csum_size) {
696 
697                         jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
698 
699                         /* Write an end-of-descriptor marker before
700                            submitting the IOs.  "tag" still points to
701                            the last tag we set up. */
702 
703                         tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
704 
705                         jbd2_descriptor_block_csum_set(journal, descriptor);
706 start_journal_io:
707                         for (i = 0; i < bufs; i++) {
708                                 struct buffer_head *bh = wbuf[i];
709                                 /*
710                                  * Compute checksum.
711                                  */
712                                 if (jbd2_has_feature_checksum(journal)) {
713                                         crc32_sum =
714                                             jbd2_checksum_data(crc32_sum, bh);
715                                 }
716 
717                                 lock_buffer(bh);
718                                 clear_buffer_dirty(bh);
719                                 set_buffer_uptodate(bh);
720                                 bh->b_end_io = journal_end_buffer_io_sync;
721                                 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
722                         }
723                         cond_resched();
724                         stats.run.rs_blocks_logged += bufs;
725 
726                         /* Force a new descriptor to be generated next
727                            time round the loop. */
728                         descriptor = NULL;
729                         bufs = 0;
730                 }
731         }
732 
733         err = journal_finish_inode_data_buffers(journal, commit_transaction);
734         if (err) {
735                 printk(KERN_WARNING
736                         "JBD2: Detected IO errors while flushing file data "
737                        "on %s\n", journal->j_devname);
738                 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
739                         jbd2_journal_abort(journal, err);
740                 err = 0;
741         }
742 
743         /*
744          * Get current oldest transaction in the log before we issue flush
745          * to the filesystem device. After the flush we can be sure that
746          * blocks of all older transactions are checkpointed to persistent
747          * storage and we will be safe to update journal start in the
748          * superblock with the numbers we get here.
749          */
750         update_tail =
751                 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
752 
753         write_lock(&journal->j_state_lock);
754         if (update_tail) {
755                 long freed = first_block - journal->j_tail;
756 
757                 if (first_block < journal->j_tail)
758                         freed += journal->j_last - journal->j_first;
759                 /* Update tail only if we free significant amount of space */
760                 if (freed < journal->j_maxlen / 4)
761                         update_tail = 0;
762         }
763         J_ASSERT(commit_transaction->t_state == T_COMMIT);
764         commit_transaction->t_state = T_COMMIT_DFLUSH;
765         write_unlock(&journal->j_state_lock);
766 
767         /* 
768          * If the journal is not located on the file system device,
769          * then we must flush the file system device before we issue
770          * the commit record
771          */
772         if (commit_transaction->t_need_data_flush &&
773             (journal->j_fs_dev != journal->j_dev) &&
774             (journal->j_flags & JBD2_BARRIER))
775                 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
776 
777         /* Done it all: now write the commit record asynchronously. */
778         if (jbd2_has_feature_async_commit(journal)) {
779                 err = journal_submit_commit_record(journal, commit_transaction,
780                                                  &cbh, crc32_sum);
781                 if (err)
782                         __jbd2_journal_abort_hard(journal);
783         }
784 
785         blk_finish_plug(&plug);
786 
787         /* Lo and behold: we have just managed to send a transaction to
788            the log.  Before we can commit it, wait for the IO so far to
789            complete.  Control buffers being written are on the
790            transaction's t_log_list queue, and metadata buffers are on
791            the io_bufs list.
792 
793            Wait for the buffers in reverse order.  That way we are
794            less likely to be woken up until all IOs have completed, and
795            so we incur less scheduling load.
796         */
797 
798         jbd_debug(3, "JBD2: commit phase 3\n");
799 
800         while (!list_empty(&io_bufs)) {
801                 struct buffer_head *bh = list_entry(io_bufs.prev,
802                                                     struct buffer_head,
803                                                     b_assoc_buffers);
804 
805                 wait_on_buffer(bh);
806                 cond_resched();
807 
808                 if (unlikely(!buffer_uptodate(bh)))
809                         err = -EIO;
810                 jbd2_unfile_log_bh(bh);
811 
812                 /*
813                  * The list contains temporary buffer heads created by
814                  * jbd2_journal_write_metadata_buffer().
815                  */
816                 BUFFER_TRACE(bh, "dumping temporary bh");
817                 __brelse(bh);
818                 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
819                 free_buffer_head(bh);
820 
821                 /* We also have to refile the corresponding shadowed buffer */
822                 jh = commit_transaction->t_shadow_list->b_tprev;
823                 bh = jh2bh(jh);
824                 clear_buffer_jwrite(bh);
825                 J_ASSERT_BH(bh, buffer_jbddirty(bh));
826                 J_ASSERT_BH(bh, !buffer_shadow(bh));
827 
828                 /* The metadata is now released for reuse, but we need
829                    to remember it against this transaction so that when
830                    we finally commit, we can do any checkpointing
831                    required. */
832                 JBUFFER_TRACE(jh, "file as BJ_Forget");
833                 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
834                 JBUFFER_TRACE(jh, "brelse shadowed buffer");
835                 __brelse(bh);
836         }
837 
838         J_ASSERT (commit_transaction->t_shadow_list == NULL);
839 
840         jbd_debug(3, "JBD2: commit phase 4\n");
841 
842         /* Here we wait for the revoke record and descriptor record buffers */
843         while (!list_empty(&log_bufs)) {
844                 struct buffer_head *bh;
845 
846                 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
847                 wait_on_buffer(bh);
848                 cond_resched();
849 
850                 if (unlikely(!buffer_uptodate(bh)))
851                         err = -EIO;
852 
853                 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
854                 clear_buffer_jwrite(bh);
855                 jbd2_unfile_log_bh(bh);
856                 __brelse(bh);           /* One for getblk */
857                 /* AKPM: bforget here */
858         }
859 
860         if (err)
861                 jbd2_journal_abort(journal, err);
862 
863         jbd_debug(3, "JBD2: commit phase 5\n");
864         write_lock(&journal->j_state_lock);
865         J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
866         commit_transaction->t_state = T_COMMIT_JFLUSH;
867         write_unlock(&journal->j_state_lock);
868 
869         if (!jbd2_has_feature_async_commit(journal)) {
870                 err = journal_submit_commit_record(journal, commit_transaction,
871                                                 &cbh, crc32_sum);
872                 if (err)
873                         __jbd2_journal_abort_hard(journal);
874         }
875         if (cbh)
876                 err = journal_wait_on_commit_record(journal, cbh);
877         if (jbd2_has_feature_async_commit(journal) &&
878             journal->j_flags & JBD2_BARRIER) {
879                 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
880         }
881 
882         if (err)
883                 jbd2_journal_abort(journal, err);
884 
885         /*
886          * Now disk caches for filesystem device are flushed so we are safe to
887          * erase checkpointed transactions from the log by updating journal
888          * superblock.
889          */
890         if (update_tail)
891                 jbd2_update_log_tail(journal, first_tid, first_block);
892 
893         /* End of a transaction!  Finally, we can do checkpoint
894            processing: any buffers committed as a result of this
895            transaction can be removed from any checkpoint list it was on
896            before. */
897 
898         jbd_debug(3, "JBD2: commit phase 6\n");
899 
900         J_ASSERT(list_empty(&commit_transaction->t_inode_list));
901         J_ASSERT(commit_transaction->t_buffers == NULL);
902         J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
903         J_ASSERT(commit_transaction->t_shadow_list == NULL);
904 
905 restart_loop:
906         /*
907          * As there are other places (journal_unmap_buffer()) adding buffers
908          * to this list we have to be careful and hold the j_list_lock.
909          */
910         spin_lock(&journal->j_list_lock);
911         while (commit_transaction->t_forget) {
912                 transaction_t *cp_transaction;
913                 struct buffer_head *bh;
914                 int try_to_free = 0;
915 
916                 jh = commit_transaction->t_forget;
917                 spin_unlock(&journal->j_list_lock);
918                 bh = jh2bh(jh);
919                 /*
920                  * Get a reference so that bh cannot be freed before we are
921                  * done with it.
922                  */
923                 get_bh(bh);
924                 jbd_lock_bh_state(bh);
925                 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
926 
927                 /*
928                  * If there is undo-protected committed data against
929                  * this buffer, then we can remove it now.  If it is a
930                  * buffer needing such protection, the old frozen_data
931                  * field now points to a committed version of the
932                  * buffer, so rotate that field to the new committed
933                  * data.
934                  *
935                  * Otherwise, we can just throw away the frozen data now.
936                  *
937                  * We also know that the frozen data has already fired
938                  * its triggers if they exist, so we can clear that too.
939                  */
940                 if (jh->b_committed_data) {
941                         jbd2_free(jh->b_committed_data, bh->b_size);
942                         jh->b_committed_data = NULL;
943                         if (jh->b_frozen_data) {
944                                 jh->b_committed_data = jh->b_frozen_data;
945                                 jh->b_frozen_data = NULL;
946                                 jh->b_frozen_triggers = NULL;
947                         }
948                 } else if (jh->b_frozen_data) {
949                         jbd2_free(jh->b_frozen_data, bh->b_size);
950                         jh->b_frozen_data = NULL;
951                         jh->b_frozen_triggers = NULL;
952                 }
953 
954                 spin_lock(&journal->j_list_lock);
955                 cp_transaction = jh->b_cp_transaction;
956                 if (cp_transaction) {
957                         JBUFFER_TRACE(jh, "remove from old cp transaction");
958                         cp_transaction->t_chp_stats.cs_dropped++;
959                         __jbd2_journal_remove_checkpoint(jh);
960                 }
961 
962                 /* Only re-checkpoint the buffer_head if it is marked
963                  * dirty.  If the buffer was added to the BJ_Forget list
964                  * by jbd2_journal_forget, it may no longer be dirty and
965                  * there's no point in keeping a checkpoint record for
966                  * it. */
967 
968                 /*
969                 * A buffer which has been freed while still being journaled by
970                 * a previous transaction.
971                 */
972                 if (buffer_freed(bh)) {
973                         /*
974                          * If the running transaction is the one containing
975                          * "add to orphan" operation (b_next_transaction !=
976                          * NULL), we have to wait for that transaction to
977                          * commit before we can really get rid of the buffer.
978                          * So just clear b_modified to not confuse transaction
979                          * credit accounting and refile the buffer to
980                          * BJ_Forget of the running transaction. If the just
981                          * committed transaction contains "add to orphan"
982                          * operation, we can completely invalidate the buffer
983                          * now. We are rather through in that since the
984                          * buffer may be still accessible when blocksize <
985                          * pagesize and it is attached to the last partial
986                          * page.
987                          */
988                         jh->b_modified = 0;
989                         if (!jh->b_next_transaction) {
990                                 clear_buffer_freed(bh);
991                                 clear_buffer_jbddirty(bh);
992                                 clear_buffer_mapped(bh);
993                                 clear_buffer_new(bh);
994                                 clear_buffer_req(bh);
995                                 bh->b_bdev = NULL;
996                         }
997                 }
998 
999                 if (buffer_jbddirty(bh)) {
1000                         JBUFFER_TRACE(jh, "add to new checkpointing trans");
1001                         __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1002                         if (is_journal_aborted(journal))
1003                                 clear_buffer_jbddirty(bh);
1004                 } else {
1005                         J_ASSERT_BH(bh, !buffer_dirty(bh));
1006                         /*
1007                          * The buffer on BJ_Forget list and not jbddirty means
1008                          * it has been freed by this transaction and hence it
1009                          * could not have been reallocated until this
1010                          * transaction has committed. *BUT* it could be
1011                          * reallocated once we have written all the data to
1012                          * disk and before we process the buffer on BJ_Forget
1013                          * list.
1014                          */
1015                         if (!jh->b_next_transaction)
1016                                 try_to_free = 1;
1017                 }
1018                 JBUFFER_TRACE(jh, "refile or unfile buffer");
1019                 __jbd2_journal_refile_buffer(jh);
1020                 jbd_unlock_bh_state(bh);
1021                 if (try_to_free)
1022                         release_buffer_page(bh);        /* Drops bh reference */
1023                 else
1024                         __brelse(bh);
1025                 cond_resched_lock(&journal->j_list_lock);
1026         }
1027         spin_unlock(&journal->j_list_lock);
1028         /*
1029          * This is a bit sleazy.  We use j_list_lock to protect transition
1030          * of a transaction into T_FINISHED state and calling
1031          * __jbd2_journal_drop_transaction(). Otherwise we could race with
1032          * other checkpointing code processing the transaction...
1033          */
1034         write_lock(&journal->j_state_lock);
1035         spin_lock(&journal->j_list_lock);
1036         /*
1037          * Now recheck if some buffers did not get attached to the transaction
1038          * while the lock was dropped...
1039          */
1040         if (commit_transaction->t_forget) {
1041                 spin_unlock(&journal->j_list_lock);
1042                 write_unlock(&journal->j_state_lock);
1043                 goto restart_loop;
1044         }
1045 
1046         /* Add the transaction to the checkpoint list
1047          * __journal_remove_checkpoint() can not destroy transaction
1048          * under us because it is not marked as T_FINISHED yet */
1049         if (journal->j_checkpoint_transactions == NULL) {
1050                 journal->j_checkpoint_transactions = commit_transaction;
1051                 commit_transaction->t_cpnext = commit_transaction;
1052                 commit_transaction->t_cpprev = commit_transaction;
1053         } else {
1054                 commit_transaction->t_cpnext =
1055                         journal->j_checkpoint_transactions;
1056                 commit_transaction->t_cpprev =
1057                         commit_transaction->t_cpnext->t_cpprev;
1058                 commit_transaction->t_cpnext->t_cpprev =
1059                         commit_transaction;
1060                 commit_transaction->t_cpprev->t_cpnext =
1061                                 commit_transaction;
1062         }
1063         spin_unlock(&journal->j_list_lock);
1064 
1065         /* Done with this transaction! */
1066 
1067         jbd_debug(3, "JBD2: commit phase 7\n");
1068 
1069         J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1070 
1071         commit_transaction->t_start = jiffies;
1072         stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1073                                               commit_transaction->t_start);
1074 
1075         /*
1076          * File the transaction statistics
1077          */
1078         stats.ts_tid = commit_transaction->t_tid;
1079         stats.run.rs_handle_count =
1080                 atomic_read(&commit_transaction->t_handle_count);
1081         trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1082                              commit_transaction->t_tid, &stats.run);
1083         stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1084 
1085         commit_transaction->t_state = T_COMMIT_CALLBACK;
1086         J_ASSERT(commit_transaction == journal->j_committing_transaction);
1087         journal->j_commit_sequence = commit_transaction->t_tid;
1088         journal->j_committing_transaction = NULL;
1089         commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1090 
1091         /*
1092          * weight the commit time higher than the average time so we don't
1093          * react too strongly to vast changes in the commit time
1094          */
1095         if (likely(journal->j_average_commit_time))
1096                 journal->j_average_commit_time = (commit_time +
1097                                 journal->j_average_commit_time*3) / 4;
1098         else
1099                 journal->j_average_commit_time = commit_time;
1100 
1101         write_unlock(&journal->j_state_lock);
1102 
1103         if (journal->j_commit_callback)
1104                 journal->j_commit_callback(journal, commit_transaction);
1105 
1106         trace_jbd2_end_commit(journal, commit_transaction);
1107         jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1108                   journal->j_commit_sequence, journal->j_tail_sequence);
1109 
1110         write_lock(&journal->j_state_lock);
1111         spin_lock(&journal->j_list_lock);
1112         commit_transaction->t_state = T_FINISHED;
1113         /* Check if the transaction can be dropped now that we are finished */
1114         if (commit_transaction->t_checkpoint_list == NULL &&
1115             commit_transaction->t_checkpoint_io_list == NULL) {
1116                 __jbd2_journal_drop_transaction(journal, commit_transaction);
1117                 jbd2_journal_free_transaction(commit_transaction);
1118         }
1119         spin_unlock(&journal->j_list_lock);
1120         write_unlock(&journal->j_state_lock);
1121         wake_up(&journal->j_wait_done_commit);
1122 
1123         /*
1124          * Calculate overall stats
1125          */
1126         spin_lock(&journal->j_history_lock);
1127         journal->j_stats.ts_tid++;
1128         journal->j_stats.ts_requested += stats.ts_requested;
1129         journal->j_stats.run.rs_wait += stats.run.rs_wait;
1130         journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1131         journal->j_stats.run.rs_running += stats.run.rs_running;
1132         journal->j_stats.run.rs_locked += stats.run.rs_locked;
1133         journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1134         journal->j_stats.run.rs_logging += stats.run.rs_logging;
1135         journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1136         journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1137         journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1138         spin_unlock(&journal->j_history_lock);
1139 }
1140 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp