From: Theodore Ts'o <tytso@mit.edu>
To: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org, Eryu Guan <eguan@redhat.com>,
stable@vger.kernel.org
Subject: Re: [PATCH 1/4] ext4: Fix deadlock during page writeback
Date: Fri, 1 Jul 2016 12:53:39 -0400 [thread overview]
Message-ID: <20160701165339.GB6075@thunk.org> (raw)
In-Reply-To: <20160701090950.GB22922@quack2.suse.cz>
On Fri, Jul 01, 2016 at 11:09:50AM +0200, Jan Kara wrote:
> But it is not safe - the bio contains pages, those pages have PageWriteback
> set and if the inode is part of the running transaction,
> ext4_journal_stop() will wait for transaction commit which will wait for
> all outstanding writeback on the inode, which will deadlock on those pages
> which are part of our unsubmitted bio. So the ordering really has to be the
> way it is...
So to be clear. the issue is that PageWriteback won't get cleared
until we potentially do a uninit->init conversion, and this is what
requires taking a transaction handle leading to the other half of the
deadlock?
... and it's probably not safe to clear the PageWriteback early in the
bio completion callback function, isn't it. Hmm....
- Ted
next prev parent reply other threads:[~2016-07-01 16:53 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-16 10:42 [PATCH 0/4] ext4: Fix deadlock during page writeback Jan Kara
2016-06-16 10:42 ` [PATCH 1/4] " Jan Kara
2016-06-30 15:05 ` Theodore Ts'o
2016-07-01 9:09 ` Jan Kara
2016-07-01 16:53 ` Theodore Ts'o [this message]
2016-07-01 17:40 ` Jan Kara
2016-07-01 21:26 ` Theodore Ts'o
2016-07-04 14:00 ` Jan Kara
2016-07-04 15:20 ` Theodore Ts'o
2016-07-04 15:47 ` Jan Kara
2016-07-05 2:43 ` Theodore Ts'o
2016-07-06 7:04 ` Jan Kara
2016-07-04 14:14 ` Theodore Ts'o
2016-07-04 15:51 ` Jan Kara
2016-07-05 3:38 ` Theodore Ts'o
2016-07-06 7:51 ` Jan Kara
2016-07-06 12:35 ` Theodore Ts'o
2016-07-06 12:52 ` Jan Kara
2016-07-06 14:27 ` Theodore Ts'o
2016-07-06 14:41 ` Jan Kara
2016-06-16 10:42 ` [PATCH 2/4] jbd2: Move lockdep instrumentation for jbd2 handles Jan Kara
2016-06-30 15:34 ` Theodore Ts'o
2016-06-16 10:42 ` [PATCH 3/4] jbd2: Move lockdep tracking to journal_s Jan Kara
2016-06-16 11:42 ` kbuild test robot
2016-06-30 15:40 ` Theodore Ts'o
2016-06-16 10:42 ` [PATCH 4/4] jbd2: Track more dependencies on transaction commit Jan Kara
2016-06-30 15:45 ` Theodore Ts'o
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