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transaction.c
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1 /*
2  * linux/fs/jbd2/transaction.c
3  *
4  * Written by Stephen C. Tweedie <[email protected]>, 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  * Generic filesystem transaction handling code; part of the ext2fs
13  * journaling system.
14  *
15  * This file manages transactions (compound commits managed by the
16  * journaling code) and handles (individual atomic operations by the
17  * filesystem).
18  */
19 
20 #include <linux/time.h>
21 #include <linux/fs.h>
22 #include <linux/jbd2.h>
23 #include <linux/errno.h>
24 #include <linux/slab.h>
25 #include <linux/timer.h>
26 #include <linux/mm.h>
27 #include <linux/highmem.h>
28 #include <linux/hrtimer.h>
29 #include <linux/backing-dev.h>
30 #include <linux/bug.h>
31 #include <linux/module.h>
32 
33 static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh);
34 static void __jbd2_journal_unfile_buffer(struct journal_head *jh);
35 
36 static struct kmem_cache *transaction_cache;
38 {
39  J_ASSERT(!transaction_cache);
40  transaction_cache = kmem_cache_create("jbd2_transaction_s",
41  sizeof(transaction_t),
42  0,
44  NULL);
45  if (transaction_cache)
46  return 0;
47  return -ENOMEM;
48 }
49 
51 {
52  if (transaction_cache) {
53  kmem_cache_destroy(transaction_cache);
54  transaction_cache = NULL;
55  }
56 }
57 
59 {
60  if (unlikely(ZERO_OR_NULL_PTR(transaction)))
61  return;
62  kmem_cache_free(transaction_cache, transaction);
63 }
64 
65 /*
66  * jbd2_get_transaction: obtain a new transaction_t object.
67  *
68  * Simply allocate and initialise a new transaction. Create it in
69  * RUNNING state and add it to the current journal (which should not
70  * have an existing running transaction: we only make a new transaction
71  * once we have started to commit the old one).
72  *
73  * Preconditions:
74  * The journal MUST be locked. We don't perform atomic mallocs on the
75  * new transaction and we can't block without protecting against other
76  * processes trying to touch the journal while it is in transition.
77  *
78  */
79 
80 static transaction_t *
81 jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
82 {
83  transaction->t_journal = journal;
84  transaction->t_state = T_RUNNING;
85  transaction->t_start_time = ktime_get();
86  transaction->t_tid = journal->j_transaction_sequence++;
87  transaction->t_expires = jiffies + journal->j_commit_interval;
88  spin_lock_init(&transaction->t_handle_lock);
89  atomic_set(&transaction->t_updates, 0);
90  atomic_set(&transaction->t_outstanding_credits, 0);
91  atomic_set(&transaction->t_handle_count, 0);
92  INIT_LIST_HEAD(&transaction->t_inode_list);
93  INIT_LIST_HEAD(&transaction->t_private_list);
94 
95  /* Set up the commit timer for the new transaction. */
96  journal->j_commit_timer.expires = round_jiffies_up(transaction->t_expires);
97  add_timer(&journal->j_commit_timer);
98 
99  J_ASSERT(journal->j_running_transaction == NULL);
100  journal->j_running_transaction = transaction;
101  transaction->t_max_wait = 0;
102  transaction->t_start = jiffies;
103 
104  return transaction;
105 }
106 
107 /*
108  * Handle management.
109  *
110  * A handle_t is an object which represents a single atomic update to a
111  * filesystem, and which tracks all of the modifications which form part
112  * of that one update.
113  */
114 
115 /*
116  * Update transaction's maximum wait time, if debugging is enabled.
117  *
118  * In order for t_max_wait to be reliable, it must be protected by a
119  * lock. But doing so will mean that start_this_handle() can not be
120  * run in parallel on SMP systems, which limits our scalability. So
121  * unless debugging is enabled, we no longer update t_max_wait, which
122  * means that maximum wait time reported by the jbd2_run_stats
123  * tracepoint will always be zero.
124  */
125 static inline void update_t_max_wait(transaction_t *transaction,
126  unsigned long ts)
127 {
128 #ifdef CONFIG_JBD2_DEBUG
129  if (jbd2_journal_enable_debug &&
130  time_after(transaction->t_start, ts)) {
131  ts = jbd2_time_diff(ts, transaction->t_start);
132  spin_lock(&transaction->t_handle_lock);
133  if (ts > transaction->t_max_wait)
134  transaction->t_max_wait = ts;
135  spin_unlock(&transaction->t_handle_lock);
136  }
137 #endif
138 }
139 
140 /*
141  * start_this_handle: Given a handle, deal with any locking or stalling
142  * needed to make sure that there is enough journal space for the handle
143  * to begin. Attach the handle to a transaction and set up the
144  * transaction's buffer credits.
145  */
146 
147 static int start_this_handle(journal_t *journal, handle_t *handle,
148  gfp_t gfp_mask)
149 {
150  transaction_t *transaction, *new_transaction = NULL;
151  tid_t tid;
152  int needed, need_to_start;
153  int nblocks = handle->h_buffer_credits;
154  unsigned long ts = jiffies;
155 
156  if (nblocks > journal->j_max_transaction_buffers) {
157  printk(KERN_ERR "JBD2: %s wants too many credits (%d > %d)\n",
158  current->comm, nblocks,
159  journal->j_max_transaction_buffers);
160  return -ENOSPC;
161  }
162 
163 alloc_transaction:
164  if (!journal->j_running_transaction) {
165  new_transaction = kmem_cache_zalloc(transaction_cache,
166  gfp_mask);
167  if (!new_transaction) {
168  /*
169  * If __GFP_FS is not present, then we may be
170  * being called from inside the fs writeback
171  * layer, so we MUST NOT fail. Since
172  * __GFP_NOFAIL is going away, we will arrange
173  * to retry the allocation ourselves.
174  */
175  if ((gfp_mask & __GFP_FS) == 0) {
177  goto alloc_transaction;
178  }
179  return -ENOMEM;
180  }
181  }
182 
183  jbd_debug(3, "New handle %p going live.\n", handle);
184 
185  /*
186  * We need to hold j_state_lock until t_updates has been incremented,
187  * for proper journal barrier handling
188  */
189 repeat:
190  read_lock(&journal->j_state_lock);
191  BUG_ON(journal->j_flags & JBD2_UNMOUNT);
192  if (is_journal_aborted(journal) ||
193  (journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) {
194  read_unlock(&journal->j_state_lock);
195  jbd2_journal_free_transaction(new_transaction);
196  return -EROFS;
197  }
198 
199  /* Wait on the journal's transaction barrier if necessary */
200  if (journal->j_barrier_count) {
201  read_unlock(&journal->j_state_lock);
202  wait_event(journal->j_wait_transaction_locked,
203  journal->j_barrier_count == 0);
204  goto repeat;
205  }
206 
207  if (!journal->j_running_transaction) {
208  read_unlock(&journal->j_state_lock);
209  if (!new_transaction)
210  goto alloc_transaction;
211  write_lock(&journal->j_state_lock);
212  if (!journal->j_running_transaction) {
213  jbd2_get_transaction(journal, new_transaction);
214  new_transaction = NULL;
215  }
216  write_unlock(&journal->j_state_lock);
217  goto repeat;
218  }
219 
220  transaction = journal->j_running_transaction;
221 
222  /*
223  * If the current transaction is locked down for commit, wait for the
224  * lock to be released.
225  */
226  if (transaction->t_state == T_LOCKED) {
227  DEFINE_WAIT(wait);
228 
229  prepare_to_wait(&journal->j_wait_transaction_locked,
231  read_unlock(&journal->j_state_lock);
232  schedule();
233  finish_wait(&journal->j_wait_transaction_locked, &wait);
234  goto repeat;
235  }
236 
237  /*
238  * If there is not enough space left in the log to write all potential
239  * buffers requested by this operation, we need to stall pending a log
240  * checkpoint to free some more log space.
241  */
242  needed = atomic_add_return(nblocks,
243  &transaction->t_outstanding_credits);
244 
245  if (needed > journal->j_max_transaction_buffers) {
246  /*
247  * If the current transaction is already too large, then start
248  * to commit it: we can then go back and attach this handle to
249  * a new transaction.
250  */
251  DEFINE_WAIT(wait);
252 
253  jbd_debug(2, "Handle %p starting new commit...\n", handle);
254  atomic_sub(nblocks, &transaction->t_outstanding_credits);
255  prepare_to_wait(&journal->j_wait_transaction_locked, &wait,
257  tid = transaction->t_tid;
258  need_to_start = !tid_geq(journal->j_commit_request, tid);
259  read_unlock(&journal->j_state_lock);
260  if (need_to_start)
261  jbd2_log_start_commit(journal, tid);
262  schedule();
263  finish_wait(&journal->j_wait_transaction_locked, &wait);
264  goto repeat;
265  }
266 
267  /*
268  * The commit code assumes that it can get enough log space
269  * without forcing a checkpoint. This is *critical* for
270  * correctness: a checkpoint of a buffer which is also
271  * associated with a committing transaction creates a deadlock,
272  * so commit simply cannot force through checkpoints.
273  *
274  * We must therefore ensure the necessary space in the journal
275  * *before* starting to dirty potentially checkpointed buffers
276  * in the new transaction.
277  *
278  * The worst part is, any transaction currently committing can
279  * reduce the free space arbitrarily. Be careful to account for
280  * those buffers when checkpointing.
281  */
282 
283  /*
284  * @@@ AKPM: This seems rather over-defensive. We're giving commit
285  * a _lot_ of headroom: 1/4 of the journal plus the size of
286  * the committing transaction. Really, we only need to give it
287  * committing_transaction->t_outstanding_credits plus "enough" for
288  * the log control blocks.
289  * Also, this test is inconsistent with the matching one in
290  * jbd2_journal_extend().
291  */
292  if (__jbd2_log_space_left(journal) < jbd_space_needed(journal)) {
293  jbd_debug(2, "Handle %p waiting for checkpoint...\n", handle);
294  atomic_sub(nblocks, &transaction->t_outstanding_credits);
295  read_unlock(&journal->j_state_lock);
296  write_lock(&journal->j_state_lock);
297  if (__jbd2_log_space_left(journal) < jbd_space_needed(journal))
298  __jbd2_log_wait_for_space(journal);
299  write_unlock(&journal->j_state_lock);
300  goto repeat;
301  }
302 
303  /* OK, account for the buffers that this operation expects to
304  * use and add the handle to the running transaction.
305  */
306  update_t_max_wait(transaction, ts);
307  handle->h_transaction = transaction;
308  atomic_inc(&transaction->t_updates);
309  atomic_inc(&transaction->t_handle_count);
310  jbd_debug(4, "Handle %p given %d credits (total %d, free %d)\n",
311  handle, nblocks,
312  atomic_read(&transaction->t_outstanding_credits),
313  __jbd2_log_space_left(journal));
314  read_unlock(&journal->j_state_lock);
315 
316  lock_map_acquire(&handle->h_lockdep_map);
317  jbd2_journal_free_transaction(new_transaction);
318  return 0;
319 }
320 
321 static struct lock_class_key jbd2_handle_key;
322 
323 /* Allocate a new handle. This should probably be in a slab... */
324 static handle_t *new_handle(int nblocks)
325 {
326  handle_t *handle = jbd2_alloc_handle(GFP_NOFS);
327  if (!handle)
328  return NULL;
329  memset(handle, 0, sizeof(*handle));
330  handle->h_buffer_credits = nblocks;
331  handle->h_ref = 1;
332 
333  lockdep_init_map(&handle->h_lockdep_map, "jbd2_handle",
334  &jbd2_handle_key, 0);
335 
336  return handle;
337 }
338 
354 handle_t *jbd2__journal_start(journal_t *journal, int nblocks, gfp_t gfp_mask)
355 {
356  handle_t *handle = journal_current_handle();
357  int err;
358 
359  if (!journal)
360  return ERR_PTR(-EROFS);
361 
362  if (handle) {
363  J_ASSERT(handle->h_transaction->t_journal == journal);
364  handle->h_ref++;
365  return handle;
366  }
367 
368  handle = new_handle(nblocks);
369  if (!handle)
370  return ERR_PTR(-ENOMEM);
371 
372  current->journal_info = handle;
373 
374  err = start_this_handle(journal, handle, gfp_mask);
375  if (err < 0) {
376  jbd2_free_handle(handle);
377  current->journal_info = NULL;
378  handle = ERR_PTR(err);
379  }
380  return handle;
381 }
383 
384 
385 handle_t *jbd2_journal_start(journal_t *journal, int nblocks)
386 {
387  return jbd2__journal_start(journal, nblocks, GFP_NOFS);
388 }
390 
391 
412 int jbd2_journal_extend(handle_t *handle, int nblocks)
413 {
414  transaction_t *transaction = handle->h_transaction;
415  journal_t *journal = transaction->t_journal;
416  int result;
417  int wanted;
418 
419  result = -EIO;
420  if (is_handle_aborted(handle))
421  goto out;
422 
423  result = 1;
424 
425  read_lock(&journal->j_state_lock);
426 
427  /* Don't extend a locked-down transaction! */
428  if (handle->h_transaction->t_state != T_RUNNING) {
429  jbd_debug(3, "denied handle %p %d blocks: "
430  "transaction not running\n", handle, nblocks);
431  goto error_out;
432  }
433 
434  spin_lock(&transaction->t_handle_lock);
435  wanted = atomic_read(&transaction->t_outstanding_credits) + nblocks;
436 
437  if (wanted > journal->j_max_transaction_buffers) {
438  jbd_debug(3, "denied handle %p %d blocks: "
439  "transaction too large\n", handle, nblocks);
440  goto unlock;
441  }
442 
443  if (wanted > __jbd2_log_space_left(journal)) {
444  jbd_debug(3, "denied handle %p %d blocks: "
445  "insufficient log space\n", handle, nblocks);
446  goto unlock;
447  }
448 
449  handle->h_buffer_credits += nblocks;
450  atomic_add(nblocks, &transaction->t_outstanding_credits);
451  result = 0;
452 
453  jbd_debug(3, "extended handle %p by %d\n", handle, nblocks);
454 unlock:
455  spin_unlock(&transaction->t_handle_lock);
456 error_out:
457  read_unlock(&journal->j_state_lock);
458 out:
459  return result;
460 }
461 
462 
477 int jbd2__journal_restart(handle_t *handle, int nblocks, gfp_t gfp_mask)
478 {
479  transaction_t *transaction = handle->h_transaction;
480  journal_t *journal = transaction->t_journal;
481  tid_t tid;
482  int need_to_start, ret;
483 
484  /* If we've had an abort of any type, don't even think about
485  * actually doing the restart! */
486  if (is_handle_aborted(handle))
487  return 0;
488 
489  /*
490  * First unlink the handle from its current transaction, and start the
491  * commit on that.
492  */
493  J_ASSERT(atomic_read(&transaction->t_updates) > 0);
494  J_ASSERT(journal_current_handle() == handle);
495 
496  read_lock(&journal->j_state_lock);
497  spin_lock(&transaction->t_handle_lock);
498  atomic_sub(handle->h_buffer_credits,
499  &transaction->t_outstanding_credits);
500  if (atomic_dec_and_test(&transaction->t_updates))
501  wake_up(&journal->j_wait_updates);
502  spin_unlock(&transaction->t_handle_lock);
503 
504  jbd_debug(2, "restarting handle %p\n", handle);
505  tid = transaction->t_tid;
506  need_to_start = !tid_geq(journal->j_commit_request, tid);
507  read_unlock(&journal->j_state_lock);
508  if (need_to_start)
509  jbd2_log_start_commit(journal, tid);
510 
511  lock_map_release(&handle->h_lockdep_map);
512  handle->h_buffer_credits = nblocks;
513  ret = start_this_handle(journal, handle, gfp_mask);
514  return ret;
515 }
517 
518 
519 int jbd2_journal_restart(handle_t *handle, int nblocks)
520 {
521  return jbd2__journal_restart(handle, nblocks, GFP_NOFS);
522 }
524 
535 void jbd2_journal_lock_updates(journal_t *journal)
536 {
537  DEFINE_WAIT(wait);
538 
539  write_lock(&journal->j_state_lock);
540  ++journal->j_barrier_count;
541 
542  /* Wait until there are no running updates */
543  while (1) {
544  transaction_t *transaction = journal->j_running_transaction;
545 
546  if (!transaction)
547  break;
548 
549  spin_lock(&transaction->t_handle_lock);
550  prepare_to_wait(&journal->j_wait_updates, &wait,
552  if (!atomic_read(&transaction->t_updates)) {
553  spin_unlock(&transaction->t_handle_lock);
554  finish_wait(&journal->j_wait_updates, &wait);
555  break;
556  }
557  spin_unlock(&transaction->t_handle_lock);
558  write_unlock(&journal->j_state_lock);
559  schedule();
560  finish_wait(&journal->j_wait_updates, &wait);
561  write_lock(&journal->j_state_lock);
562  }
563  write_unlock(&journal->j_state_lock);
564 
565  /*
566  * We have now established a barrier against other normal updates, but
567  * we also need to barrier against other jbd2_journal_lock_updates() calls
568  * to make sure that we serialise special journal-locked operations
569  * too.
570  */
571  mutex_lock(&journal->j_barrier);
572 }
573 
582 void jbd2_journal_unlock_updates (journal_t *journal)
583 {
584  J_ASSERT(journal->j_barrier_count != 0);
585 
586  mutex_unlock(&journal->j_barrier);
587  write_lock(&journal->j_state_lock);
588  --journal->j_barrier_count;
589  write_unlock(&journal->j_state_lock);
590  wake_up(&journal->j_wait_transaction_locked);
591 }
592 
593 static void warn_dirty_buffer(struct buffer_head *bh)
594 {
595  char b[BDEVNAME_SIZE];
596 
598  "JBD2: Spotted dirty metadata buffer (dev = %s, blocknr = %llu). "
599  "There's a risk of filesystem corruption in case of system "
600  "crash.\n",
601  bdevname(bh->b_bdev, b), (unsigned long long)bh->b_blocknr);
602 }
603 
604 /*
605  * If the buffer is already part of the current transaction, then there
606  * is nothing we need to do. If it is already part of a prior
607  * transaction which we are still committing to disk, then we need to
608  * make sure that we do not overwrite the old copy: we do copy-out to
609  * preserve the copy going to disk. We also account the buffer against
610  * the handle's metadata buffer credits (unless the buffer is already
611  * part of the transaction, that is).
612  *
613  */
614 static int
615 do_get_write_access(handle_t *handle, struct journal_head *jh,
616  int force_copy)
617 {
618  struct buffer_head *bh;
620  journal_t *journal;
621  int error;
622  char *frozen_buffer = NULL;
623  int need_copy = 0;
624 
625  if (is_handle_aborted(handle))
626  return -EROFS;
627 
628  transaction = handle->h_transaction;
629  journal = transaction->t_journal;
630 
631  jbd_debug(5, "journal_head %p, force_copy %d\n", jh, force_copy);
632 
633  JBUFFER_TRACE(jh, "entry");
634 repeat:
635  bh = jh2bh(jh);
636 
637  /* @@@ Need to check for errors here at some point. */
638 
639  lock_buffer(bh);
640  jbd_lock_bh_state(bh);
641 
642  /* We now hold the buffer lock so it is safe to query the buffer
643  * state. Is the buffer dirty?
644  *
645  * If so, there are two possibilities. The buffer may be
646  * non-journaled, and undergoing a quite legitimate writeback.
647  * Otherwise, it is journaled, and we don't expect dirty buffers
648  * in that state (the buffers should be marked JBD_Dirty
649  * instead.) So either the IO is being done under our own
650  * control and this is a bug, or it's a third party IO such as
651  * dump(8) (which may leave the buffer scheduled for read ---
652  * ie. locked but not dirty) or tune2fs (which may actually have
653  * the buffer dirtied, ugh.) */
654 
655  if (buffer_dirty(bh)) {
656  /*
657  * First question: is this buffer already part of the current
658  * transaction or the existing committing transaction?
659  */
660  if (jh->b_transaction) {
661  J_ASSERT_JH(jh,
662  jh->b_transaction == transaction ||
663  jh->b_transaction ==
664  journal->j_committing_transaction);
665  if (jh->b_next_transaction)
666  J_ASSERT_JH(jh, jh->b_next_transaction ==
667  transaction);
668  warn_dirty_buffer(bh);
669  }
670  /*
671  * In any case we need to clean the dirty flag and we must
672  * do it under the buffer lock to be sure we don't race
673  * with running write-out.
674  */
675  JBUFFER_TRACE(jh, "Journalling dirty buffer");
676  clear_buffer_dirty(bh);
677  set_buffer_jbddirty(bh);
678  }
679 
680  unlock_buffer(bh);
681 
682  error = -EROFS;
683  if (is_handle_aborted(handle)) {
684  jbd_unlock_bh_state(bh);
685  goto out;
686  }
687  error = 0;
688 
689  /*
690  * The buffer is already part of this transaction if b_transaction or
691  * b_next_transaction points to it
692  */
693  if (jh->b_transaction == transaction ||
694  jh->b_next_transaction == transaction)
695  goto done;
696 
697  /*
698  * this is the first time this transaction is touching this buffer,
699  * reset the modified flag
700  */
701  jh->b_modified = 0;
702 
703  /*
704  * If there is already a copy-out version of this buffer, then we don't
705  * need to make another one
706  */
707  if (jh->b_frozen_data) {
708  JBUFFER_TRACE(jh, "has frozen data");
709  J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
711  goto done;
712  }
713 
714  /* Is there data here we need to preserve? */
715 
716  if (jh->b_transaction && jh->b_transaction != transaction) {
717  JBUFFER_TRACE(jh, "owned by older transaction");
718  J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
719  J_ASSERT_JH(jh, jh->b_transaction ==
720  journal->j_committing_transaction);
721 
722  /* There is one case we have to be very careful about.
723  * If the committing transaction is currently writing
724  * this buffer out to disk and has NOT made a copy-out,
725  * then we cannot modify the buffer contents at all
726  * right now. The essence of copy-out is that it is the
727  * extra copy, not the primary copy, which gets
728  * journaled. If the primary copy is already going to
729  * disk then we cannot do copy-out here. */
730 
731  if (jh->b_jlist == BJ_Shadow) {
732  DEFINE_WAIT_BIT(wait, &bh->b_state, BH_Unshadow);
733  wait_queue_head_t *wqh;
734 
735  wqh = bit_waitqueue(&bh->b_state, BH_Unshadow);
736 
737  JBUFFER_TRACE(jh, "on shadow: sleep");
738  jbd_unlock_bh_state(bh);
739  /* commit wakes up all shadow buffers after IO */
740  for ( ; ; ) {
741  prepare_to_wait(wqh, &wait.wait,
743  if (jh->b_jlist != BJ_Shadow)
744  break;
745  schedule();
746  }
747  finish_wait(wqh, &wait.wait);
748  goto repeat;
749  }
750 
751  /* Only do the copy if the currently-owning transaction
752  * still needs it. If it is on the Forget list, the
753  * committing transaction is past that stage. The
754  * buffer had better remain locked during the kmalloc,
755  * but that should be true --- we hold the journal lock
756  * still and the buffer is already on the BUF_JOURNAL
757  * list so won't be flushed.
758  *
759  * Subtle point, though: if this is a get_undo_access,
760  * then we will be relying on the frozen_data to contain
761  * the new value of the committed_data record after the
762  * transaction, so we HAVE to force the frozen_data copy
763  * in that case. */
764 
765  if (jh->b_jlist != BJ_Forget || force_copy) {
766  JBUFFER_TRACE(jh, "generate frozen data");
767  if (!frozen_buffer) {
768  JBUFFER_TRACE(jh, "allocate memory for buffer");
769  jbd_unlock_bh_state(bh);
770  frozen_buffer =
771  jbd2_alloc(jh2bh(jh)->b_size,
772  GFP_NOFS);
773  if (!frozen_buffer) {
775  "%s: OOM for frozen_buffer\n",
776  __func__);
777  JBUFFER_TRACE(jh, "oom!");
778  error = -ENOMEM;
779  jbd_lock_bh_state(bh);
780  goto done;
781  }
782  goto repeat;
783  }
784  jh->b_frozen_data = frozen_buffer;
785  frozen_buffer = NULL;
786  need_copy = 1;
787  }
789  }
790 
791 
792  /*
793  * Finally, if the buffer is not journaled right now, we need to make
794  * sure it doesn't get written to disk before the caller actually
795  * commits the new data
796  */
797  if (!jh->b_transaction) {
798  JBUFFER_TRACE(jh, "no transaction");
799  J_ASSERT_JH(jh, !jh->b_next_transaction);
800  JBUFFER_TRACE(jh, "file as BJ_Reserved");
801  spin_lock(&journal->j_list_lock);
802  __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved);
803  spin_unlock(&journal->j_list_lock);
804  }
805 
806 done:
807  if (need_copy) {
808  struct page *page;
809  int offset;
810  char *source;
811 
812  J_EXPECT_JH(jh, buffer_uptodate(jh2bh(jh)),
813  "Possible IO failure.\n");
814  page = jh2bh(jh)->b_page;
815  offset = offset_in_page(jh2bh(jh)->b_data);
816  source = kmap_atomic(page);
817  /* Fire data frozen trigger just before we copy the data */
818  jbd2_buffer_frozen_trigger(jh, source + offset,
819  jh->b_triggers);
820  memcpy(jh->b_frozen_data, source+offset, jh2bh(jh)->b_size);
821  kunmap_atomic(source);
822 
823  /*
824  * Now that the frozen data is saved off, we need to store
825  * any matching triggers.
826  */
827  jh->b_frozen_triggers = jh->b_triggers;
828  }
829  jbd_unlock_bh_state(bh);
830 
831  /*
832  * If we are about to journal a buffer, then any revoke pending on it is
833  * no longer valid
834  */
835  jbd2_journal_cancel_revoke(handle, jh);
836 
837 out:
838  if (unlikely(frozen_buffer)) /* It's usually NULL */
839  jbd2_free(frozen_buffer, bh->b_size);
840 
841  JBUFFER_TRACE(jh, "exit");
842  return error;
843 }
844 
856 int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh)
857 {
859  int rc;
860 
861  /* We do not want to get caught playing with fields which the
862  * log thread also manipulates. Make sure that the buffer
863  * completes any outstanding IO before proceeding. */
864  rc = do_get_write_access(handle, jh, 0);
866  return rc;
867 }
868 
869 
870 /*
871  * When the user wants to journal a newly created buffer_head
872  * (ie. getblk() returned a new buffer and we are going to populate it
873  * manually rather than reading off disk), then we need to keep the
874  * buffer_head locked until it has been completely filled with new
875  * data. In this case, we should be able to make the assertion that
876  * the bh is not already part of an existing transaction.
877  *
878  * The buffer should already be locked by the caller by this point.
879  * There is no lock ranking violation: it was a newly created,
880  * unlocked buffer beforehand. */
881 
889 int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh)
890 {
891  transaction_t *transaction = handle->h_transaction;
892  journal_t *journal = transaction->t_journal;
894  int err;
895 
896  jbd_debug(5, "journal_head %p\n", jh);
897  err = -EROFS;
898  if (is_handle_aborted(handle))
899  goto out;
900  err = 0;
901 
902  JBUFFER_TRACE(jh, "entry");
903  /*
904  * The buffer may already belong to this transaction due to pre-zeroing
905  * in the filesystem's new_block code. It may also be on the previous,
906  * committing transaction's lists, but it HAS to be in Forget state in
907  * that case: the transaction must have deleted the buffer for it to be
908  * reused here.
909  */
910  jbd_lock_bh_state(bh);
911  spin_lock(&journal->j_list_lock);
912  J_ASSERT_JH(jh, (jh->b_transaction == transaction ||
913  jh->b_transaction == NULL ||
914  (jh->b_transaction == journal->j_committing_transaction &&
915  jh->b_jlist == BJ_Forget)));
916 
917  J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
918  J_ASSERT_JH(jh, buffer_locked(jh2bh(jh)));
919 
920  if (jh->b_transaction == NULL) {
921  /*
922  * Previous jbd2_journal_forget() could have left the buffer
923  * with jbddirty bit set because it was being committed. When
924  * the commit finished, we've filed the buffer for
925  * checkpointing and marked it dirty. Now we are reallocating
926  * the buffer so the transaction freeing it must have
927  * committed and so it's safe to clear the dirty bit.
928  */
929  clear_buffer_dirty(jh2bh(jh));
930  /* first access by this transaction */
931  jh->b_modified = 0;
932 
933  JBUFFER_TRACE(jh, "file as BJ_Reserved");
934  __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved);
935  } else if (jh->b_transaction == journal->j_committing_transaction) {
936  /* first access by this transaction */
937  jh->b_modified = 0;
938 
939  JBUFFER_TRACE(jh, "set next transaction");
941  }
942  spin_unlock(&journal->j_list_lock);
943  jbd_unlock_bh_state(bh);
944 
945  /*
946  * akpm: I added this. ext3_alloc_branch can pick up new indirect
947  * blocks which contain freed but then revoked metadata. We need
948  * to cancel the revoke in case we end up freeing it yet again
949  * and the reallocating as data - this would cause a second revoke,
950  * which hits an assertion error.
951  */
952  JBUFFER_TRACE(jh, "cancelling revoke");
953  jbd2_journal_cancel_revoke(handle, jh);
954 out:
956  return err;
957 }
958 
985 int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh)
986 {
987  int err;
989  char *committed_data = NULL;
990 
991  JBUFFER_TRACE(jh, "entry");
992 
993  /*
994  * Do this first --- it can drop the journal lock, so we want to
995  * make sure that obtaining the committed_data is done
996  * atomically wrt. completion of any outstanding commits.
997  */
998  err = do_get_write_access(handle, jh, 1);
999  if (err)
1000  goto out;
1001 
1002 repeat:
1003  if (!jh->b_committed_data) {
1004  committed_data = jbd2_alloc(jh2bh(jh)->b_size, GFP_NOFS);
1005  if (!committed_data) {
1006  printk(KERN_EMERG "%s: No memory for committed data\n",
1007  __func__);
1008  err = -ENOMEM;
1009  goto out;
1010  }
1011  }
1012 
1013  jbd_lock_bh_state(bh);
1014  if (!jh->b_committed_data) {
1015  /* Copy out the current buffer contents into the
1016  * preserved, committed copy. */
1017  JBUFFER_TRACE(jh, "generate b_committed data");
1018  if (!committed_data) {
1019  jbd_unlock_bh_state(bh);
1020  goto repeat;
1021  }
1022 
1023  jh->b_committed_data = committed_data;
1024  committed_data = NULL;
1025  memcpy(jh->b_committed_data, bh->b_data, bh->b_size);
1026  }
1027  jbd_unlock_bh_state(bh);
1028 out:
1030  if (unlikely(committed_data))
1031  jbd2_free(committed_data, bh->b_size);
1032  return err;
1033 }
1034 
1046 void jbd2_journal_set_triggers(struct buffer_head *bh,
1047  struct jbd2_buffer_trigger_type *type)
1048 {
1049  struct journal_head *jh = bh2jh(bh);
1050 
1051  jh->b_triggers = type;
1052 }
1053 
1054 void jbd2_buffer_frozen_trigger(struct journal_head *jh, void *mapped_data,
1055  struct jbd2_buffer_trigger_type *triggers)
1056 {
1057  struct buffer_head *bh = jh2bh(jh);
1058 
1059  if (!triggers || !triggers->t_frozen)
1060  return;
1061 
1062  triggers->t_frozen(triggers, bh, mapped_data, bh->b_size);
1063 }
1064 
1066  struct jbd2_buffer_trigger_type *triggers)
1067 {
1068  if (!triggers || !triggers->t_abort)
1069  return;
1070 
1071  triggers->t_abort(triggers, jh2bh(jh));
1072 }
1073 
1074 
1075 
1099 int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
1100 {
1101  transaction_t *transaction = handle->h_transaction;
1102  journal_t *journal = transaction->t_journal;
1103  struct journal_head *jh = bh2jh(bh);
1104  int ret = 0;
1105 
1106  jbd_debug(5, "journal_head %p\n", jh);
1107  JBUFFER_TRACE(jh, "entry");
1108  if (is_handle_aborted(handle))
1109  goto out;
1110  if (!buffer_jbd(bh)) {
1111  ret = -EUCLEAN;
1112  goto out;
1113  }
1114 
1115  jbd_lock_bh_state(bh);
1116 
1117  if (jh->b_modified == 0) {
1118  /*
1119  * This buffer's got modified and becoming part
1120  * of the transaction. This needs to be done
1121  * once a transaction -bzzz
1122  */
1123  jh->b_modified = 1;
1124  J_ASSERT_JH(jh, handle->h_buffer_credits > 0);
1125  handle->h_buffer_credits--;
1126  }
1127 
1128  /*
1129  * fastpath, to avoid expensive locking. If this buffer is already
1130  * on the running transaction's metadata list there is nothing to do.
1131  * Nobody can take it off again because there is a handle open.
1132  * I _think_ we're OK here with SMP barriers - a mistaken decision will
1133  * result in this test being false, so we go in and take the locks.
1134  */
1135  if (jh->b_transaction == transaction && jh->b_jlist == BJ_Metadata) {
1136  JBUFFER_TRACE(jh, "fastpath");
1137  if (unlikely(jh->b_transaction !=
1138  journal->j_running_transaction)) {
1139  printk(KERN_EMERG "JBD: %s: "
1140  "jh->b_transaction (%llu, %p, %u) != "
1141  "journal->j_running_transaction (%p, %u)",
1142  journal->j_devname,
1143  (unsigned long long) bh->b_blocknr,
1144  jh->b_transaction,
1145  jh->b_transaction ? jh->b_transaction->t_tid : 0,
1146  journal->j_running_transaction,
1147  journal->j_running_transaction ?
1148  journal->j_running_transaction->t_tid : 0);
1149  ret = -EINVAL;
1150  }
1151  goto out_unlock_bh;
1152  }
1153 
1154  set_buffer_jbddirty(bh);
1155 
1156  /*
1157  * Metadata already on the current transaction list doesn't
1158  * need to be filed. Metadata on another transaction's list must
1159  * be committing, and will be refiled once the commit completes:
1160  * leave it alone for now.
1161  */
1162  if (jh->b_transaction != transaction) {
1163  JBUFFER_TRACE(jh, "already on other transaction");
1164  if (unlikely(jh->b_transaction !=
1165  journal->j_committing_transaction)) {
1166  printk(KERN_EMERG "JBD: %s: "
1167  "jh->b_transaction (%llu, %p, %u) != "
1168  "journal->j_committing_transaction (%p, %u)",
1169  journal->j_devname,
1170  (unsigned long long) bh->b_blocknr,
1171  jh->b_transaction,
1172  jh->b_transaction ? jh->b_transaction->t_tid : 0,
1173  journal->j_committing_transaction,
1174  journal->j_committing_transaction ?
1175  journal->j_committing_transaction->t_tid : 0);
1176  ret = -EINVAL;
1177  }
1178  if (unlikely(jh->b_next_transaction != transaction)) {
1179  printk(KERN_EMERG "JBD: %s: "
1180  "jh->b_next_transaction (%llu, %p, %u) != "
1181  "transaction (%p, %u)",
1182  journal->j_devname,
1183  (unsigned long long) bh->b_blocknr,
1184  jh->b_next_transaction,
1185  jh->b_next_transaction ?
1186  jh->b_next_transaction->t_tid : 0,
1187  transaction, transaction->t_tid);
1188  ret = -EINVAL;
1189  }
1190  /* And this case is illegal: we can't reuse another
1191  * transaction's data buffer, ever. */
1192  goto out_unlock_bh;
1193  }
1194 
1195  /* That test should have eliminated the following case: */
1196  J_ASSERT_JH(jh, jh->b_frozen_data == NULL);
1197 
1198  JBUFFER_TRACE(jh, "file as BJ_Metadata");
1199  spin_lock(&journal->j_list_lock);
1200  __jbd2_journal_file_buffer(jh, handle->h_transaction, BJ_Metadata);
1201  spin_unlock(&journal->j_list_lock);
1202 out_unlock_bh:
1203  jbd_unlock_bh_state(bh);
1204 out:
1205  JBUFFER_TRACE(jh, "exit");
1206  WARN_ON(ret); /* All errors are bugs, so dump the stack */
1207  return ret;
1208 }
1209 
1210 /*
1211  * jbd2_journal_release_buffer: undo a get_write_access without any buffer
1212  * updates, if the update decided in the end that it didn't need access.
1213  *
1214  */
1215 void
1216 jbd2_journal_release_buffer(handle_t *handle, struct buffer_head *bh)
1217 {
1218  BUFFER_TRACE(bh, "entry");
1219 }
1220 
1238 int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh)
1239 {
1240  transaction_t *transaction = handle->h_transaction;
1241  journal_t *journal = transaction->t_journal;
1242  struct journal_head *jh;
1243  int drop_reserve = 0;
1244  int err = 0;
1245  int was_modified = 0;
1246 
1247  BUFFER_TRACE(bh, "entry");
1248 
1249  jbd_lock_bh_state(bh);
1250  spin_lock(&journal->j_list_lock);
1251 
1252  if (!buffer_jbd(bh))
1253  goto not_jbd;
1254  jh = bh2jh(bh);
1255 
1256  /* Critical error: attempting to delete a bitmap buffer, maybe?
1257  * Don't do any jbd operations, and return an error. */
1258  if (!J_EXPECT_JH(jh, !jh->b_committed_data,
1259  "inconsistent data on disk")) {
1260  err = -EIO;
1261  goto not_jbd;
1262  }
1263 
1264  /* keep track of wether or not this transaction modified us */
1265  was_modified = jh->b_modified;
1266 
1267  /*
1268  * The buffer's going from the transaction, we must drop
1269  * all references -bzzz
1270  */
1271  jh->b_modified = 0;
1272 
1273  if (jh->b_transaction == handle->h_transaction) {
1274  J_ASSERT_JH(jh, !jh->b_frozen_data);
1275 
1276  /* If we are forgetting a buffer which is already part
1277  * of this transaction, then we can just drop it from
1278  * the transaction immediately. */
1279  clear_buffer_dirty(bh);
1280  clear_buffer_jbddirty(bh);
1281 
1282  JBUFFER_TRACE(jh, "belongs to current transaction: unfile");
1283 
1284  /*
1285  * we only want to drop a reference if this transaction
1286  * modified the buffer
1287  */
1288  if (was_modified)
1289  drop_reserve = 1;
1290 
1291  /*
1292  * We are no longer going to journal this buffer.
1293  * However, the commit of this transaction is still
1294  * important to the buffer: the delete that we are now
1295  * processing might obsolete an old log entry, so by
1296  * committing, we can satisfy the buffer's checkpoint.
1297  *
1298  * So, if we have a checkpoint on the buffer, we should
1299  * now refile the buffer on our BJ_Forget list so that
1300  * we know to remove the checkpoint after we commit.
1301  */
1302 
1303  if (jh->b_cp_transaction) {
1304  __jbd2_journal_temp_unlink_buffer(jh);
1305  __jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
1306  } else {
1307  __jbd2_journal_unfile_buffer(jh);
1308  if (!buffer_jbd(bh)) {
1309  spin_unlock(&journal->j_list_lock);
1310  jbd_unlock_bh_state(bh);
1311  __bforget(bh);
1312  goto drop;
1313  }
1314  }
1315  } else if (jh->b_transaction) {
1316  J_ASSERT_JH(jh, (jh->b_transaction ==
1317  journal->j_committing_transaction));
1318  /* However, if the buffer is still owned by a prior
1319  * (committing) transaction, we can't drop it yet... */
1320  JBUFFER_TRACE(jh, "belongs to older transaction");
1321  /* ... but we CAN drop it from the new transaction if we
1322  * have also modified it since the original commit. */
1323 
1324  if (jh->b_next_transaction) {
1325  J_ASSERT(jh->b_next_transaction == transaction);
1326  jh->b_next_transaction = NULL;
1327 
1328  /*
1329  * only drop a reference if this transaction modified
1330  * the buffer
1331  */
1332  if (was_modified)
1333  drop_reserve = 1;
1334  }
1335  }
1336 
1337 not_jbd:
1338  spin_unlock(&journal->j_list_lock);
1339  jbd_unlock_bh_state(bh);
1340  __brelse(bh);
1341 drop:
1342  if (drop_reserve) {
1343  /* no need to reserve log space for this block -bzzz */
1344  handle->h_buffer_credits++;
1345  }
1346  return err;
1347 }
1348 
1365 int jbd2_journal_stop(handle_t *handle)
1366 {
1367  transaction_t *transaction = handle->h_transaction;
1368  journal_t *journal = transaction->t_journal;
1369  int err, wait_for_commit = 0;
1370  tid_t tid;
1371  pid_t pid;
1372 
1373  J_ASSERT(journal_current_handle() == handle);
1374 
1375  if (is_handle_aborted(handle))
1376  err = -EIO;
1377  else {
1378  J_ASSERT(atomic_read(&transaction->t_updates) > 0);
1379  err = 0;
1380  }
1381 
1382  if (--handle->h_ref > 0) {
1383  jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1,
1384  handle->h_ref);
1385  return err;
1386  }
1387 
1388  jbd_debug(4, "Handle %p going down\n", handle);
1389 
1390  /*
1391  * Implement synchronous transaction batching. If the handle
1392  * was synchronous, don't force a commit immediately. Let's
1393  * yield and let another thread piggyback onto this
1394  * transaction. Keep doing that while new threads continue to
1395  * arrive. It doesn't cost much - we're about to run a commit
1396  * and sleep on IO anyway. Speeds up many-threaded, many-dir
1397  * operations by 30x or more...
1398  *
1399  * We try and optimize the sleep time against what the
1400  * underlying disk can do, instead of having a static sleep
1401  * time. This is useful for the case where our storage is so
1402  * fast that it is more optimal to go ahead and force a flush
1403  * and wait for the transaction to be committed than it is to
1404  * wait for an arbitrary amount of time for new writers to
1405  * join the transaction. We achieve this by measuring how
1406  * long it takes to commit a transaction, and compare it with
1407  * how long this transaction has been running, and if run time
1408  * < commit time then we sleep for the delta and commit. This
1409  * greatly helps super fast disks that would see slowdowns as
1410  * more threads started doing fsyncs.
1411  *
1412  * But don't do this if this process was the most recent one
1413  * to perform a synchronous write. We do this to detect the
1414  * case where a single process is doing a stream of sync
1415  * writes. No point in waiting for joiners in that case.
1416  */
1417  pid = current->pid;
1418  if (handle->h_sync && journal->j_last_sync_writer != pid) {
1419  u64 commit_time, trans_time;
1420 
1421  journal->j_last_sync_writer = pid;
1422 
1423  read_lock(&journal->j_state_lock);
1424  commit_time = journal->j_average_commit_time;
1425  read_unlock(&journal->j_state_lock);
1426 
1427  trans_time = ktime_to_ns(ktime_sub(ktime_get(),
1428  transaction->t_start_time));
1429 
1430  commit_time = max_t(u64, commit_time,
1431  1000*journal->j_min_batch_time);
1432  commit_time = min_t(u64, commit_time,
1433  1000*journal->j_max_batch_time);
1434 
1435  if (trans_time < commit_time) {
1436  ktime_t expires = ktime_add_ns(ktime_get(),
1437  commit_time);
1440  }
1441  }
1442 
1443  if (handle->h_sync)
1444  transaction->t_synchronous_commit = 1;
1445  current->journal_info = NULL;
1446  atomic_sub(handle->h_buffer_credits,
1447  &transaction->t_outstanding_credits);
1448 
1449  /*
1450  * If the handle is marked SYNC, we need to set another commit
1451  * going! We also want to force a commit if the current
1452  * transaction is occupying too much of the log, or if the
1453  * transaction is too old now.
1454  */
1455  if (handle->h_sync ||
1456  (atomic_read(&transaction->t_outstanding_credits) >
1457  journal->j_max_transaction_buffers) ||
1458  time_after_eq(jiffies, transaction->t_expires)) {
1459  /* Do this even for aborted journals: an abort still
1460  * completes the commit thread, it just doesn't write
1461  * anything to disk. */
1462 
1463  jbd_debug(2, "transaction too old, requesting commit for "
1464  "handle %p\n", handle);
1465  /* This is non-blocking */
1466  jbd2_log_start_commit(journal, transaction->t_tid);
1467 
1468  /*
1469  * Special case: JBD2_SYNC synchronous updates require us
1470  * to wait for the commit to complete.
1471  */
1472  if (handle->h_sync && !(current->flags & PF_MEMALLOC))
1473  wait_for_commit = 1;
1474  }
1475 
1476  /*
1477  * Once we drop t_updates, if it goes to zero the transaction
1478  * could start committing on us and eventually disappear. So
1479  * once we do this, we must not dereference transaction
1480  * pointer again.
1481  */
1482  tid = transaction->t_tid;
1483  if (atomic_dec_and_test(&transaction->t_updates)) {
1484  wake_up(&journal->j_wait_updates);
1485  if (journal->j_barrier_count)
1486  wake_up(&journal->j_wait_transaction_locked);
1487  }
1488 
1489  if (wait_for_commit)
1490  err = jbd2_log_wait_commit(journal, tid);
1491 
1492  lock_map_release(&handle->h_lockdep_map);
1493 
1494  jbd2_free_handle(handle);
1495  return err;
1496 }
1497 
1506 int jbd2_journal_force_commit(journal_t *journal)
1507 {
1508  handle_t *handle;
1509  int ret;
1510 
1511  handle = jbd2_journal_start(journal, 1);
1512  if (IS_ERR(handle)) {
1513  ret = PTR_ERR(handle);
1514  } else {
1515  handle->h_sync = 1;
1516  ret = jbd2_journal_stop(handle);
1517  }
1518  return ret;
1519 }
1520 
1521 /*
1522  *
1523  * List management code snippets: various functions for manipulating the
1524  * transaction buffer lists.
1525  *
1526  */
1527 
1528 /*
1529  * Append a buffer to a transaction list, given the transaction's list head
1530  * pointer.
1531  *
1532  * j_list_lock is held.
1533  *
1534  * jbd_lock_bh_state(jh2bh(jh)) is held.
1535  */
1536 
1537 static inline void
1538 __blist_add_buffer(struct journal_head **list, struct journal_head *jh)
1539 {
1540  if (!*list) {
1541  jh->b_tnext = jh->b_tprev = jh;
1542  *list = jh;
1543  } else {
1544  /* Insert at the tail of the list to preserve order */
1545  struct journal_head *first = *list, *last = first->b_tprev;
1546  jh->b_tprev = last;
1547  jh->b_tnext = first;
1548  last->b_tnext = first->b_tprev = jh;
1549  }
1550 }
1551 
1552 /*
1553  * Remove a buffer from a transaction list, given the transaction's list
1554  * head pointer.
1555  *
1556  * Called with j_list_lock held, and the journal may not be locked.
1557  *
1558  * jbd_lock_bh_state(jh2bh(jh)) is held.
1559  */
1560 
1561 static inline void
1562 __blist_del_buffer(struct journal_head **list, struct journal_head *jh)
1563 {
1564  if (*list == jh) {
1565  *list = jh->b_tnext;
1566  if (*list == jh)
1567  *list = NULL;
1568  }
1569  jh->b_tprev->b_tnext = jh->b_tnext;
1570  jh->b_tnext->b_tprev = jh->b_tprev;
1571 }
1572 
1573 /*
1574  * Remove a buffer from the appropriate transaction list.
1575  *
1576  * Note that this function can *change* the value of
1577  * bh->b_transaction->t_buffers, t_forget, t_iobuf_list, t_shadow_list,
1578  * t_log_list or t_reserved_list. If the caller is holding onto a copy of one
1579  * of these pointers, it could go bad. Generally the caller needs to re-read
1580  * the pointer from the transaction_t.
1581  *
1582  * Called under j_list_lock.
1583  */
1584 static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh)
1585 {
1586  struct journal_head **list = NULL;
1588  struct buffer_head *bh = jh2bh(jh);
1589 
1590  J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
1591  transaction = jh->b_transaction;
1592  if (transaction)
1593  assert_spin_locked(&transaction->t_journal->j_list_lock);
1594 
1595  J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
1596  if (jh->b_jlist != BJ_None)
1597  J_ASSERT_JH(jh, transaction != NULL);
1598 
1599  switch (jh->b_jlist) {
1600  case BJ_None:
1601  return;
1602  case BJ_Metadata:
1603  transaction->t_nr_buffers--;
1604  J_ASSERT_JH(jh, transaction->t_nr_buffers >= 0);
1605  list = &transaction->t_buffers;
1606  break;
1607  case BJ_Forget:
1608  list = &transaction->t_forget;
1609  break;
1610  case BJ_IO:
1611  list = &transaction->t_iobuf_list;
1612  break;
1613  case BJ_Shadow:
1614  list = &transaction->t_shadow_list;
1615  break;
1616  case BJ_LogCtl:
1617  list = &transaction->t_log_list;
1618  break;
1619  case BJ_Reserved:
1620  list = &transaction->t_reserved_list;
1621  break;
1622  }
1623 
1624  __blist_del_buffer(list, jh);
1625  jh->b_jlist = BJ_None;
1626  if (test_clear_buffer_jbddirty(bh))
1627  mark_buffer_dirty(bh); /* Expose it to the VM */
1628 }
1629 
1630 /*
1631  * Remove buffer from all transactions.
1632  *
1633  * Called with bh_state lock and j_list_lock
1634  *
1635  * jh and bh may be already freed when this function returns.
1636  */
1637 static void __jbd2_journal_unfile_buffer(struct journal_head *jh)
1638 {
1639  __jbd2_journal_temp_unlink_buffer(jh);
1640  jh->b_transaction = NULL;
1642 }
1643 
1644 void jbd2_journal_unfile_buffer(journal_t *journal, struct journal_head *jh)
1645 {
1646  struct buffer_head *bh = jh2bh(jh);
1647 
1648  /* Get reference so that buffer cannot be freed before we unlock it */
1649  get_bh(bh);
1650  jbd_lock_bh_state(bh);
1651  spin_lock(&journal->j_list_lock);
1652  __jbd2_journal_unfile_buffer(jh);
1653  spin_unlock(&journal->j_list_lock);
1654  jbd_unlock_bh_state(bh);
1655  __brelse(bh);
1656 }
1657 
1658 /*
1659  * Called from jbd2_journal_try_to_free_buffers().
1660  *
1661  * Called under jbd_lock_bh_state(bh)
1662  */
1663 static void
1664 __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh)
1665 {
1666  struct journal_head *jh;
1667 
1668  jh = bh2jh(bh);
1669 
1670  if (buffer_locked(bh) || buffer_dirty(bh))
1671  goto out;
1672 
1673  if (jh->b_next_transaction != NULL)
1674  goto out;
1675 
1676  spin_lock(&journal->j_list_lock);
1677  if (jh->b_cp_transaction != NULL && jh->b_transaction == NULL) {
1678  /* written-back checkpointed metadata buffer */
1679  JBUFFER_TRACE(jh, "remove from checkpoint list");
1681  }
1682  spin_unlock(&journal->j_list_lock);
1683 out:
1684  return;
1685 }
1686 
1725 int jbd2_journal_try_to_free_buffers(journal_t *journal,
1726  struct page *page, gfp_t gfp_mask)
1727 {
1728  struct buffer_head *head;
1729  struct buffer_head *bh;
1730  int ret = 0;
1731 
1732  J_ASSERT(PageLocked(page));
1733 
1734  head = page_buffers(page);
1735  bh = head;
1736  do {
1737  struct journal_head *jh;
1738 
1739  /*
1740  * We take our own ref against the journal_head here to avoid
1741  * having to add tons of locking around each instance of
1742  * jbd2_journal_put_journal_head().
1743  */
1745  if (!jh)
1746  continue;
1747 
1748  jbd_lock_bh_state(bh);
1749  __journal_try_to_free_buffer(journal, bh);
1751  jbd_unlock_bh_state(bh);
1752  if (buffer_jbd(bh))
1753  goto busy;
1754  } while ((bh = bh->b_this_page) != head);
1755 
1756  ret = try_to_free_buffers(page);
1757 
1758 busy:
1759  return ret;
1760 }
1761 
1762 /*
1763  * This buffer is no longer needed. If it is on an older transaction's
1764  * checkpoint list we need to record it on this transaction's forget list
1765  * to pin this buffer (and hence its checkpointing transaction) down until
1766  * this transaction commits. If the buffer isn't on a checkpoint list, we
1767  * release it.
1768  * Returns non-zero if JBD no longer has an interest in the buffer.
1769  *
1770  * Called under j_list_lock.
1771  *
1772  * Called under jbd_lock_bh_state(bh).
1773  */
1774 static int __dispose_buffer(struct journal_head *jh, transaction_t *transaction)
1775 {
1776  int may_free = 1;
1777  struct buffer_head *bh = jh2bh(jh);
1778 
1779  if (jh->b_cp_transaction) {
1780  JBUFFER_TRACE(jh, "on running+cp transaction");
1781  __jbd2_journal_temp_unlink_buffer(jh);
1782  /*
1783  * We don't want to write the buffer anymore, clear the
1784  * bit so that we don't confuse checks in
1785  * __journal_file_buffer
1786  */
1787  clear_buffer_dirty(bh);
1788  __jbd2_journal_file_buffer(jh, transaction, BJ_Forget);
1789  may_free = 0;
1790  } else {
1791  JBUFFER_TRACE(jh, "on running transaction");
1792  __jbd2_journal_unfile_buffer(jh);
1793  }
1794  return may_free;
1795 }
1796 
1797 /*
1798  * jbd2_journal_invalidatepage
1799  *
1800  * This code is tricky. It has a number of cases to deal with.
1801  *
1802  * There are two invariants which this code relies on:
1803  *
1804  * i_size must be updated on disk before we start calling invalidatepage on the
1805  * data.
1806  *
1807  * This is done in ext3 by defining an ext3_setattr method which
1808  * updates i_size before truncate gets going. By maintaining this
1809  * invariant, we can be sure that it is safe to throw away any buffers
1810  * attached to the current transaction: once the transaction commits,
1811  * we know that the data will not be needed.
1812  *
1813  * Note however that we can *not* throw away data belonging to the
1814  * previous, committing transaction!
1815  *
1816  * Any disk blocks which *are* part of the previous, committing
1817  * transaction (and which therefore cannot be discarded immediately) are
1818  * not going to be reused in the new running transaction
1819  *
1820  * The bitmap committed_data images guarantee this: any block which is
1821  * allocated in one transaction and removed in the next will be marked
1822  * as in-use in the committed_data bitmap, so cannot be reused until
1823  * the next transaction to delete the block commits. This means that
1824  * leaving committing buffers dirty is quite safe: the disk blocks
1825  * cannot be reallocated to a different file and so buffer aliasing is
1826  * not possible.
1827  *
1828  *
1829  * The above applies mainly to ordered data mode. In writeback mode we
1830  * don't make guarantees about the order in which data hits disk --- in
1831  * particular we don't guarantee that new dirty data is flushed before
1832  * transaction commit --- so it is always safe just to discard data
1833  * immediately in that mode. --sct
1834  */
1835 
1836 /*
1837  * The journal_unmap_buffer helper function returns zero if the buffer
1838  * concerned remains pinned as an anonymous buffer belonging to an older
1839  * transaction.
1840  *
1841  * We're outside-transaction here. Either or both of j_running_transaction
1842  * and j_committing_transaction may be NULL.
1843  */
1844 static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh,
1845  int partial_page)
1846 {
1848  struct journal_head *jh;
1849  int may_free = 1;
1850 
1851  BUFFER_TRACE(bh, "entry");
1852 
1853 retry:
1854  /*
1855  * It is safe to proceed here without the j_list_lock because the
1856  * buffers cannot be stolen by try_to_free_buffers as long as we are
1857  * holding the page lock. --sct
1858  */
1859 
1860  if (!buffer_jbd(bh))
1861  goto zap_buffer_unlocked;
1862 
1863  /* OK, we have data buffer in journaled mode */
1864  write_lock(&journal->j_state_lock);
1865  jbd_lock_bh_state(bh);
1866  spin_lock(&journal->j_list_lock);
1867 
1869  if (!jh)
1870  goto zap_buffer_no_jh;
1871 
1872  /*
1873  * We cannot remove the buffer from checkpoint lists until the
1874  * transaction adding inode to orphan list (let's call it T)
1875  * is committed. Otherwise if the transaction changing the
1876  * buffer would be cleaned from the journal before T is
1877  * committed, a crash will cause that the correct contents of
1878  * the buffer will be lost. On the other hand we have to
1879  * clear the buffer dirty bit at latest at the moment when the
1880  * transaction marking the buffer as freed in the filesystem
1881  * structures is committed because from that moment on the
1882  * block can be reallocated and used by a different page.
1883  * Since the block hasn't been freed yet but the inode has
1884  * already been added to orphan list, it is safe for us to add
1885  * the buffer to BJ_Forget list of the newest transaction.
1886  *
1887  * Also we have to clear buffer_mapped flag of a truncated buffer
1888  * because the buffer_head may be attached to the page straddling
1889  * i_size (can happen only when blocksize < pagesize) and thus the
1890  * buffer_head can be reused when the file is extended again. So we end
1891  * up keeping around invalidated buffers attached to transactions'
1892  * BJ_Forget list just to stop checkpointing code from cleaning up
1893  * the transaction this buffer was modified in.
1894  */
1895  transaction = jh->b_transaction;
1896  if (transaction == NULL) {
1897  /* First case: not on any transaction. If it
1898  * has no checkpoint link, then we can zap it:
1899  * it's a writeback-mode buffer so we don't care
1900  * if it hits disk safely. */
1901  if (!jh->b_cp_transaction) {
1902  JBUFFER_TRACE(jh, "not on any transaction: zap");
1903  goto zap_buffer;
1904  }
1905 
1906  if (!buffer_dirty(bh)) {
1907  /* bdflush has written it. We can drop it now */
1908  goto zap_buffer;
1909  }
1910 
1911  /* OK, it must be in the journal but still not
1912  * written fully to disk: it's metadata or
1913  * journaled data... */
1914 
1915  if (journal->j_running_transaction) {
1916  /* ... and once the current transaction has
1917  * committed, the buffer won't be needed any
1918  * longer. */
1919  JBUFFER_TRACE(jh, "checkpointed: add to BJ_Forget");
1920  may_free = __dispose_buffer(jh,
1921  journal->j_running_transaction);
1922  goto zap_buffer;
1923  } else {
1924  /* There is no currently-running transaction. So the
1925  * orphan record which we wrote for this file must have
1926  * passed into commit. We must attach this buffer to
1927  * the committing transaction, if it exists. */
1928  if (journal->j_committing_transaction) {
1929  JBUFFER_TRACE(jh, "give to committing trans");
1930  may_free = __dispose_buffer(jh,
1931  journal->j_committing_transaction);
1932  goto zap_buffer;
1933  } else {
1934  /* The orphan record's transaction has
1935  * committed. We can cleanse this buffer */
1936  clear_buffer_jbddirty(bh);
1937  goto zap_buffer;
1938  }
1939  }
1940  } else if (transaction == journal->j_committing_transaction) {
1941  JBUFFER_TRACE(jh, "on committing transaction");
1942  /*
1943  * The buffer is committing, we simply cannot touch
1944  * it. If the page is straddling i_size we have to wait
1945  * for commit and try again.
1946  */
1947  if (partial_page) {
1948  tid_t tid = journal->j_committing_transaction->t_tid;
1949 
1951  spin_unlock(&journal->j_list_lock);
1952  jbd_unlock_bh_state(bh);
1953  write_unlock(&journal->j_state_lock);
1954  jbd2_log_wait_commit(journal, tid);
1955  goto retry;
1956  }
1957  /*
1958  * OK, buffer won't be reachable after truncate. We just set
1959  * j_next_transaction to the running transaction (if there is
1960  * one) and mark buffer as freed so that commit code knows it
1961  * should clear dirty bits when it is done with the buffer.
1962  */
1963  set_buffer_freed(bh);
1964  if (journal->j_running_transaction && buffer_jbddirty(bh))
1965  jh->b_next_transaction = journal->j_running_transaction;
1967  spin_unlock(&journal->j_list_lock);
1968  jbd_unlock_bh_state(bh);
1969  write_unlock(&journal->j_state_lock);
1970  return 0;
1971  } else {
1972  /* Good, the buffer belongs to the running transaction.
1973  * We are writing our own transaction's data, not any
1974  * previous one's, so it is safe to throw it away
1975  * (remember that we expect the filesystem to have set
1976  * i_size already for this truncate so recovery will not
1977  * expose the disk blocks we are discarding here.) */
1978  J_ASSERT_JH(jh, transaction == journal->j_running_transaction);
1979  JBUFFER_TRACE(jh, "on running transaction");
1980  may_free = __dispose_buffer(jh, transaction);
1981  }
1982 
1983 zap_buffer:
1984  /*
1985  * This is tricky. Although the buffer is truncated, it may be reused
1986  * if blocksize < pagesize and it is attached to the page straddling
1987  * EOF. Since the buffer might have been added to BJ_Forget list of the
1988  * running transaction, journal_get_write_access() won't clear
1989  * b_modified and credit accounting gets confused. So clear b_modified
1990  * here.
1991  */
1992  jh->b_modified = 0;
1994 zap_buffer_no_jh:
1995  spin_unlock(&journal->j_list_lock);
1996  jbd_unlock_bh_state(bh);
1997  write_unlock(&journal->j_state_lock);
1998 zap_buffer_unlocked:
1999  clear_buffer_dirty(bh);
2000  J_ASSERT_BH(bh, !buffer_jbddirty(bh));
2001  clear_buffer_mapped(bh);
2002  clear_buffer_req(bh);
2003  clear_buffer_new(bh);
2004  clear_buffer_delay(bh);
2005  clear_buffer_unwritten(bh);
2006  bh->b_bdev = NULL;
2007  return may_free;
2008 }
2009 
2019 void jbd2_journal_invalidatepage(journal_t *journal,
2020  struct page *page,
2021  unsigned long offset)
2022 {
2023  struct buffer_head *head, *bh, *next;
2024  unsigned int curr_off = 0;
2025  int may_free = 1;
2026 
2027  if (!PageLocked(page))
2028  BUG();
2029  if (!page_has_buffers(page))
2030  return;
2031 
2032  /* We will potentially be playing with lists other than just the
2033  * data lists (especially for journaled data mode), so be
2034  * cautious in our locking. */
2035 
2036  head = bh = page_buffers(page);
2037  do {
2038  unsigned int next_off = curr_off + bh->b_size;
2039  next = bh->b_this_page;
2040 
2041  if (offset <= curr_off) {
2042  /* This block is wholly outside the truncation point */
2043  lock_buffer(bh);
2044  may_free &= journal_unmap_buffer(journal, bh,
2045  offset > 0);
2046  unlock_buffer(bh);
2047  }
2048  curr_off = next_off;
2049  bh = next;
2050 
2051  } while (bh != head);
2052 
2053  if (!offset) {
2054  if (may_free && try_to_free_buffers(page))
2055  J_ASSERT(!page_has_buffers(page));
2056  }
2057 }
2058 
2059 /*
2060  * File a buffer on the given transaction list.
2061  */
2063  transaction_t *transaction, int jlist)
2064 {
2065  struct journal_head **list = NULL;
2066  int was_dirty = 0;
2067  struct buffer_head *bh = jh2bh(jh);
2068 
2069  J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
2070  assert_spin_locked(&transaction->t_journal->j_list_lock);
2071 
2072  J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
2073  J_ASSERT_JH(jh, jh->b_transaction == transaction ||
2074  jh->b_transaction == NULL);
2075 
2076  if (jh->b_transaction && jh->b_jlist == jlist)
2077  return;
2078 
2079  if (jlist == BJ_Metadata || jlist == BJ_Reserved ||
2080  jlist == BJ_Shadow || jlist == BJ_Forget) {
2081  /*
2082  * For metadata buffers, we track dirty bit in buffer_jbddirty
2083  * instead of buffer_dirty. We should not see a dirty bit set
2084  * here because we clear it in do_get_write_access but e.g.
2085  * tune2fs can modify the sb and set the dirty bit at any time
2086  * so we try to gracefully handle that.
2087  */
2088  if (buffer_dirty(bh))
2089  warn_dirty_buffer(bh);
2090  if (test_clear_buffer_dirty(bh) ||
2091  test_clear_buffer_jbddirty(bh))
2092  was_dirty = 1;
2093  }
2094 
2095  if (jh->b_transaction)
2096  __jbd2_journal_temp_unlink_buffer(jh);
2097  else
2099  jh->b_transaction = transaction;
2100 
2101  switch (jlist) {
2102  case BJ_None:
2103  J_ASSERT_JH(jh, !jh->b_committed_data);
2104  J_ASSERT_JH(jh, !jh->b_frozen_data);
2105  return;
2106  case BJ_Metadata:
2107  transaction->t_nr_buffers++;
2108  list = &transaction->t_buffers;
2109  break;
2110  case BJ_Forget:
2111  list = &transaction->t_forget;
2112  break;
2113  case BJ_IO:
2114  list = &transaction->t_iobuf_list;
2115  break;
2116  case BJ_Shadow:
2117  list = &transaction->t_shadow_list;
2118  break;
2119  case BJ_LogCtl:
2120  list = &transaction->t_log_list;
2121  break;
2122  case BJ_Reserved:
2123  list = &transaction->t_reserved_list;
2124  break;
2125  }
2126 
2127  __blist_add_buffer(list, jh);
2128  jh->b_jlist = jlist;
2129 
2130  if (was_dirty)
2131  set_buffer_jbddirty(bh);
2132 }
2133 
2135  transaction_t *transaction, int jlist)
2136 {
2137  jbd_lock_bh_state(jh2bh(jh));
2138  spin_lock(&transaction->t_journal->j_list_lock);
2139  __jbd2_journal_file_buffer(jh, transaction, jlist);
2140  spin_unlock(&transaction->t_journal->j_list_lock);
2141  jbd_unlock_bh_state(jh2bh(jh));
2142 }
2143 
2144 /*
2145  * Remove a buffer from its current buffer list in preparation for
2146  * dropping it from its current transaction entirely. If the buffer has
2147  * already started to be used by a subsequent transaction, refile the
2148  * buffer on that transaction's metadata list.
2149  *
2150  * Called under j_list_lock
2151  * Called under jbd_lock_bh_state(jh2bh(jh))
2152  *
2153  * jh and bh may be already free when this function returns
2154  */
2156 {
2157  int was_dirty, jlist;
2158  struct buffer_head *bh = jh2bh(jh);
2159 
2160  J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
2161  if (jh->b_transaction)
2162  assert_spin_locked(&jh->b_transaction->t_journal->j_list_lock);
2163 
2164  /* If the buffer is now unused, just drop it. */
2165  if (jh->b_next_transaction == NULL) {
2166  __jbd2_journal_unfile_buffer(jh);
2167  return;
2168  }
2169 
2170  /*
2171  * It has been modified by a later transaction: add it to the new
2172  * transaction's metadata list.
2173  */
2174 
2175  was_dirty = test_clear_buffer_jbddirty(bh);
2176  __jbd2_journal_temp_unlink_buffer(jh);
2177  /*
2178  * We set b_transaction here because b_next_transaction will inherit
2179  * our jh reference and thus __jbd2_journal_file_buffer() must not
2180  * take a new one.
2181  */
2183  jh->b_next_transaction = NULL;
2184  if (buffer_freed(bh))
2185  jlist = BJ_Forget;
2186  else if (jh->b_modified)
2187  jlist = BJ_Metadata;
2188  else
2189  jlist = BJ_Reserved;
2190  __jbd2_journal_file_buffer(jh, jh->b_transaction, jlist);
2191  J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING);
2192 
2193  if (was_dirty)
2194  set_buffer_jbddirty(bh);
2195 }
2196 
2197 /*
2198  * __jbd2_journal_refile_buffer() with necessary locking added. We take our
2199  * bh reference so that we can safely unlock bh.
2200  *
2201  * The jh and bh may be freed by this call.
2202  */
2203 void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh)
2204 {
2205  struct buffer_head *bh = jh2bh(jh);
2206 
2207  /* Get reference so that buffer cannot be freed before we unlock it */
2208  get_bh(bh);
2209  jbd_lock_bh_state(bh);
2210  spin_lock(&journal->j_list_lock);
2212  jbd_unlock_bh_state(bh);
2213  spin_unlock(&journal->j_list_lock);
2214  __brelse(bh);
2215 }
2216 
2217 /*
2218  * File inode in the inode list of the handle's transaction
2219  */
2220 int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode)
2221 {
2222  transaction_t *transaction = handle->h_transaction;
2223  journal_t *journal = transaction->t_journal;
2224 
2225  if (is_handle_aborted(handle))
2226  return -EIO;
2227 
2228  jbd_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino,
2229  transaction->t_tid);
2230 
2231  /*
2232  * First check whether inode isn't already on the transaction's
2233  * lists without taking the lock. Note that this check is safe
2234  * without the lock as we cannot race with somebody removing inode
2235  * from the transaction. The reason is that we remove inode from the
2236  * transaction only in journal_release_jbd_inode() and when we commit
2237  * the transaction. We are guarded from the first case by holding
2238  * a reference to the inode. We are safe against the second case
2239  * because if jinode->i_transaction == transaction, commit code
2240  * cannot touch the transaction because we hold reference to it,
2241  * and if jinode->i_next_transaction == transaction, commit code
2242  * will only file the inode where we want it.
2243  */
2244  if (jinode->i_transaction == transaction ||
2245  jinode->i_next_transaction == transaction)
2246  return 0;
2247 
2248  spin_lock(&journal->j_list_lock);
2249 
2250  if (jinode->i_transaction == transaction ||
2251  jinode->i_next_transaction == transaction)
2252  goto done;
2253 
2254  /*
2255  * We only ever set this variable to 1 so the test is safe. Since
2256  * t_need_data_flush is likely to be set, we do the test to save some
2257  * cacheline bouncing
2258  */
2259  if (!transaction->t_need_data_flush)
2260  transaction->t_need_data_flush = 1;
2261  /* On some different transaction's list - should be
2262  * the committing one */
2263  if (jinode->i_transaction) {
2264  J_ASSERT(jinode->i_next_transaction == NULL);
2265  J_ASSERT(jinode->i_transaction ==
2266  journal->j_committing_transaction);
2267  jinode->i_next_transaction = transaction;
2268  goto done;
2269  }
2270  /* Not on any transaction list... */
2271  J_ASSERT(!jinode->i_next_transaction);
2272  jinode->i_transaction = transaction;
2273  list_add(&jinode->i_list, &transaction->t_inode_list);
2274 done:
2275  spin_unlock(&journal->j_list_lock);
2276 
2277  return 0;
2278 }
2279 
2280 /*
2281  * File truncate and transaction commit interact with each other in a
2282  * non-trivial way. If a transaction writing data block A is
2283  * committing, we cannot discard the data by truncate until we have
2284  * written them. Otherwise if we crashed after the transaction with
2285  * write has committed but before the transaction with truncate has
2286  * committed, we could see stale data in block A. This function is a
2287  * helper to solve this problem. It starts writeout of the truncated
2288  * part in case it is in the committing transaction.
2289  *
2290  * Filesystem code must call this function when inode is journaled in
2291  * ordered mode before truncation happens and after the inode has been
2292  * placed on orphan list with the new inode size. The second condition
2293  * avoids the race that someone writes new data and we start
2294  * committing the transaction after this function has been called but
2295  * before a transaction for truncate is started (and furthermore it
2296  * allows us to optimize the case where the addition to orphan list
2297  * happens in the same transaction as write --- we don't have to write
2298  * any data in such case).
2299  */
2301  struct jbd2_inode *jinode,
2302  loff_t new_size)
2303 {
2304  transaction_t *inode_trans, *commit_trans;
2305  int ret = 0;
2306 
2307  /* This is a quick check to avoid locking if not necessary */
2308  if (!jinode->i_transaction)
2309  goto out;
2310  /* Locks are here just to force reading of recent values, it is
2311  * enough that the transaction was not committing before we started
2312  * a transaction adding the inode to orphan list */
2313  read_lock(&journal->j_state_lock);
2314  commit_trans = journal->j_committing_transaction;
2315  read_unlock(&journal->j_state_lock);
2316  spin_lock(&journal->j_list_lock);
2317  inode_trans = jinode->i_transaction;
2318  spin_unlock(&journal->j_list_lock);
2319  if (inode_trans == commit_trans) {
2320  ret = filemap_fdatawrite_range(jinode->i_vfs_inode->i_mapping,
2321  new_size, LLONG_MAX);
2322  if (ret)
2323  jbd2_journal_abort(journal, ret);
2324  }
2325 out:
2326  return ret;
2327 }