From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs <linux-xfs@vger.kernel.org>
Subject: Re: [PATCH] xfs: avoid mount-time deadlock in CoW extent recovery
Date: Tue, 16 May 2017 18:06:27 -0700 [thread overview]
Message-ID: <20170517010627.GR4519@birch.djwong.org> (raw)
In-Reply-To: <20170517003931.GN17542@dastard>
On Wed, May 17, 2017 at 10:39:31AM +1000, Dave Chinner wrote:
> On Tue, May 16, 2017 at 12:27:48PM -0700, Darrick J. Wong wrote:
> > If a malicious user corrupts the refcount btree to cause a cycle between
> > different levels of the tree, the next mount attempt will deadlock in
> > the CoW recovery routine while grabbing buffer locks. We can use the
> > ability to re-grab a buffer that was previous locked to a transaction to
> > avoid deadlocks, so do that here.
> >
> > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
>
> Missing comments in the code explaining the deadlock being avoided
> by using xfs_trans_alloc_empty()....
Heh, ok.
--D
>
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@fromorbit.com
> --
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prev parent reply other threads:[~2017-05-17 1:06 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-16 19:27 [PATCH] xfs: avoid mount-time deadlock in CoW extent recovery Darrick J. Wong
2017-05-17 0:39 ` Dave Chinner
2017-05-17 1:06 ` Darrick J. Wong [this message]
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