From: Ted Ts'o <tytso@mit.edu>
To: Kazuya Mio <k-mio@sx.jp.nec.com>
Cc: ext4 <linux-ext4@vger.kernel.org>, Andreas Dilger <adilger@dilger.ca>
Subject: Re: [PATCH] ext4: fix the deadlock in mpage_da_map_and_submit()
Date: Thu, 20 Oct 2011 19:47:12 -0400 [thread overview]
Message-ID: <20111020234712.GJ17210@thunk.org> (raw)
In-Reply-To: <4E968F8E.5070802@sx.jp.nec.com>
On Thu, Oct 13, 2011 at 04:13:18PM +0900, Kazuya Mio wrote:
> If ext4_jbd2_file_inode() in mpage_da_map_and_submit() fails due to journal
> abort, this function returns to caller without unlocking the page.
> It leads to the deadlock, and the patch fixes this issue by calling
> mpage_da_submit_io().
>
> Signed-off-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Applied, thanks.
This is an area where we should really clean things up next merge
window, though. I'm a little uneasy that we will potentially write
back some blocks even though the journal has been aborted (we do this
in other error paths, so this isn't a criticism of this patch, just of
the current state of affairs).
The problem mpage_da_submit_io() is the only way we have to unlock the
pages. In the future we should probably have a separate path to
unlock the pages in case of an error. We might also want to merge
mpage_da_submit_io() and mpage_da_map_and_submit(), and to also clean
up a number of comments which are out of date. (For example,
mpage_da_submit_io() no longer uses ext4_writepage().)
- Ted
prev parent reply other threads:[~2011-10-21 1:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-13 7:13 [PATCH] ext4: fix the deadlock in mpage_da_map_and_submit() Kazuya Mio
2011-10-20 23:47 ` Ted Ts'o [this message]
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