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| author |   Jan Kara <jack@suse.cz> | 2007-12-04 23:45:27 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-12-05 09:21:20 -0800 |
| commit | d4beaf4ab5f89496f2bcf67db62ad95d99bfeff6 (patch) | |
| tree | ae6d005199017e9a0ade169fd69cb73d6c0ac88f /include/linux/jbd.h | |
| parent | mm: fix XIP file writes (diff) | |
| download | linux-dev-d4beaf4ab5f89496f2bcf67db62ad95d99bfeff6.tar.xz linux-dev-d4beaf4ab5f89496f2bcf67db62ad95d99bfeff6.zip | |
jbd: Fix assertion failure in fs/jbd/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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
| -rw-r--r-- | include/linux/jbd.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/jbd.h b/include/linux/jbd.h index 16e7ed855a18..d9ecd13393b0 100644 --- a/include/linux/jbd.h +++ b/include/linux/jbd.h @@ -439,6 +439,8 @@ struct transaction_s /* * Transaction's current state * [no locking - only kjournald alters this] + * [j_list_lock] guards transition of a transaction into T_FINISHED + * state and subsequent call of __journal_drop_transaction() * FIXME: needs barriers * KLUDGE: [use j_state_lock] */ |