From: Jan Kara <jack@suse.cz>
To: Kazuya Mio <k-mio@sx.jp.nec.com>
Cc: Jan Kara <jack@suse.cz>, ext4 <linux-ext4@vger.kernel.org>,
Theodore Tso <tytso@mit.edu>, Andreas Dilger <adilger@dilger.ca>
Subject: Re: [BUG] aborted ext4 leads to inifinity loop in balance_dirty_pages
Date: Mon, 14 Nov 2011 12:11:10 +0100 [thread overview]
Message-ID: <20111114111110.GA5230@quack.suse.cz> (raw)
In-Reply-To: <4EC0E827.6040504@sx.jp.nec.com>
On Mon 14-11-11 19:06:31, Kazuya Mio wrote:
> 2011/11/08 9:03, Jan Kara wrote:
> > On Fri 28-10-11 14:34:31, Kazuya Mio wrote:
> >> 2011/10/25 22:40, Jan Kara wrote:
> >>> Please no. Generally this boils down to what do we do with dirty data
> >>> when there's error in writing them out. Currently we just throw them away
> >>> (e.g. in media error case) but I don't think that's a generally good thing
> >>> because e.g. admin may want to copy the data to other working storage or
> >>> so. So I think we should rather keep the data and provide a mechanism for
> >>> userspace to ask kernel to get rid of the data (so that we don't eventually
> >>> run OOM).
> >>
> >> I see. I agree with you.
> >>
> >>>> Do you have any ideas?
> >>> So the question is what would you like to achieve. If you just want to
> >>> unblock a thread then a solution would be to make a thread at
> >>> balance_dirty_pages() killable. If generally you want to get rid of dirty
> >>> memory, then I don't have a really good answer but throwing dirty data away
> >>> seems like a bad answer to me.
> >>
> >> The problem is that we cannot unmount the corrupted filesystem due to
> >> un-killable dd process. We must bring down the system to resume the service
> >> with no dirty pages. I think it is important for the service continuity
> >> to be able to kill the thread handling in balance_dirty_pages().
> > OK, attached are two patches based on latest Linus's tree that should
> > make your task killable. Can you test them?
>
> Sorry for the late reply.
> I confirmed that these patches fix the problem.
>
> Reported-and-tested-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Thanks for testing! I've sent patches for inclusion...
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
prev parent reply other threads:[~2011-11-14 11:11 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-25 12:04 [BUG] aborted ext4 leads to inifinity loop in balance_dirty_pages Kazuya Mio
2011-10-25 13:40 ` Jan Kara
2011-10-28 5:34 ` Kazuya Mio
2011-11-01 23:13 ` Jan Kara
2011-11-02 5:24 ` Kazuya Mio
2011-11-07 8:00 ` Dmitry Monakhov
2011-11-07 17:29 ` Jan Kara
2011-11-07 17:45 ` Dmitry Monakhov
2011-11-07 21:23 ` Jan Kara
2011-11-08 0:03 ` Jan Kara
2011-11-09 8:28 ` Kazuya Mio
2011-11-09 11:15 ` Jan Kara
2011-11-14 10:06 ` Kazuya Mio
2011-11-14 11:11 ` Jan Kara [this message]
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