This is a note to let you know that I've just added the patch titled
jbd: Fix lock ordering bug in journal_unmap_buffer()
to the 3.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
jbd-fix-lock-ordering-bug-in-journal_unmap_buffer.patch
and it can be found in the queue-3.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 25389bb207987b5774182f763b9fb65ff08761c8 Mon Sep 17 00:00:00 2001
From: Jan Kara <[email protected]>
Date: Fri, 23 Nov 2012 14:03:04 +0100
Subject: jbd: Fix lock ordering bug in journal_unmap_buffer()
From: Jan Kara <[email protected]>
commit 25389bb207987b5774182f763b9fb65ff08761c8 upstream.
Commit 09e05d48 introduced a wait for transaction commit into
journal_unmap_buffer() in the case we are truncating a buffer undergoing commit
in the page stradding i_size on a filesystem with blocksize < pagesize. Sadly
we forgot to drop buffer lock before waiting for transaction commit and thus
deadlock is possible when kjournald wants to lock the buffer.
Fix the problem by dropping the buffer lock before waiting for transaction
commit. Since we are still holding page lock (and that is OK), buffer cannot
disappear under us.
Signed-off-by: Jan Kara <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
fs/jbd/transaction.c | 2 ++
1 file changed, 2 insertions(+)
--- a/fs/jbd/transaction.c
+++ b/fs/jbd/transaction.c
@@ -1961,7 +1961,9 @@ retry:
spin_unlock(&journal->j_list_lock);
jbd_unlock_bh_state(bh);
spin_unlock(&journal->j_state_lock);
+ unlock_buffer(bh);
log_wait_commit(journal, tid);
+ lock_buffer(bh);
goto retry;
}
/*
Patches currently in stable-queue which might be from [email protected] are
queue-3.6/writeback-put-unused-inodes-to-lru-after-writeback-completion.patch
queue-3.6/jbd-fix-lock-ordering-bug-in-journal_unmap_buffer.patch
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