diff options
author | Jan Kara <jack@suse.cz> | 2008-01-28 23:58:27 -0500 |
---|---|---|
committer | Theodore Ts'o <tytso@mit.edu> | 2008-01-28 23:58:27 -0500 |
commit | f5a7a6b0d9b6af7d46124ed3f6b3995225cb62d0 (patch) | |
tree | cbb2bc79a488461bf3bec9b60d15e21717dc8360 /fs/jbd2 | |
parent | 36df53f4a3e445175fc1e9d7f433599482ec6d7f (diff) |
jbd2: Fix assertion failure in fs/jbd2/checkpoint.c
Before we start committing a transaction, we call
__journal_clean_checkpoint_list() to cleanup transaction's written-back
buffers.
If this call happens to remove all of them (and there were already some
buffers), __journal_remove_checkpoint() will decide to free the transaction
because it isn't (yet) a committing transaction and soon we fail some
assertion - the transaction really isn't ready to be freed :).
We change the check in __journal_remove_checkpoint() to free only a
transaction in T_FINISHED state. The locking there is subtle though (as
everywhere in JBD ;(). We use j_list_lock to protect the check and a
subsequent call to __journal_drop_transaction() and do the same in the end
of journal_commit_transaction() which is the only place where a transaction
can get to T_FINISHED state.
Probably I'm too paranoid here and such locking is not really necessary -
checkpoint lists are processed only from log_do_checkpoint() where a
transaction must be already committed to be processed or from
__journal_clean_checkpoint_list() where kjournald itself calls it and thus
transaction cannot change state either. Better be safe if something
changes in future...
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/jbd2')
-rw-r--r-- | fs/jbd2/checkpoint.c | 12 | ||||
-rw-r--r-- | fs/jbd2/commit.c | 8 |
2 files changed, 10 insertions, 10 deletions
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c index 3fccde7ba008..7e958c86242f 100644 --- a/fs/jbd2/checkpoint.c +++ b/fs/jbd2/checkpoint.c | |||
@@ -602,15 +602,15 @@ int __jbd2_journal_remove_checkpoint(struct journal_head *jh) | |||
602 | 602 | ||
603 | /* | 603 | /* |
604 | * There is one special case to worry about: if we have just pulled the | 604 | * There is one special case to worry about: if we have just pulled the |
605 | * buffer off a committing transaction's forget list, then even if the | 605 | * buffer off a running or committing transaction's checkpoing list, |
606 | * checkpoint list is empty, the transaction obviously cannot be | 606 | * then even if the checkpoint list is empty, the transaction obviously |
607 | * dropped! | 607 | * cannot be dropped! |
608 | * | 608 | * |
609 | * The locking here around j_committing_transaction is a bit sleazy. | 609 | * The locking here around t_state is a bit sleazy. |
610 | * See the comment at the end of jbd2_journal_commit_transaction(). | 610 | * See the comment at the end of jbd2_journal_commit_transaction(). |
611 | */ | 611 | */ |
612 | if (transaction == journal->j_committing_transaction) { | 612 | if (transaction->t_state != T_FINISHED) { |
613 | JBUFFER_TRACE(jh, "belongs to committing transaction"); | 613 | JBUFFER_TRACE(jh, "belongs to running/committing transaction"); |
614 | goto out; | 614 | goto out; |
615 | } | 615 | } |
616 | 616 | ||
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c index 6986f334c643..39b5cee3dd8a 100644 --- a/fs/jbd2/commit.c +++ b/fs/jbd2/commit.c | |||
@@ -867,10 +867,10 @@ restart_loop: | |||
867 | } | 867 | } |
868 | spin_unlock(&journal->j_list_lock); | 868 | spin_unlock(&journal->j_list_lock); |
869 | /* | 869 | /* |
870 | * This is a bit sleazy. We borrow j_list_lock to protect | 870 | * This is a bit sleazy. We use j_list_lock to protect transition |
871 | * journal->j_committing_transaction in __jbd2_journal_remove_checkpoint. | 871 | * of a transaction into T_FINISHED state and calling |
872 | * Really, __jbd2_journal_remove_checkpoint should be using j_state_lock but | 872 | * __jbd2_journal_drop_transaction(). Otherwise we could race with |
873 | * it's a bit hassle to hold that across __jbd2_journal_remove_checkpoint | 873 | * other checkpointing code processing the transaction... |
874 | */ | 874 | */ |
875 | spin_lock(&journal->j_state_lock); | 875 | spin_lock(&journal->j_state_lock); |
876 | spin_lock(&journal->j_list_lock); | 876 | spin_lock(&journal->j_list_lock); |