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From: John Kacur <jkacur@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: linux-kernel@vger.kernel.org, xfs-masters@oss.sgi.com,
	Thomas Gleixner <tglx@linutronix.de>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [xfs-masters] INFO: possible circular locking dependency detected
Date: Sun, 11 Oct 2009 17:59:54 +0200 (CEST)	[thread overview]
Message-ID: <alpine.LFD.2.00.0910111759030.12574@localhost.localdomain> (raw)
In-Reply-To: <20091011124616.GA4081@lst.de>



On Sun, 11 Oct 2009, Christoph Hellwig wrote:

> This has been around for a long time, the VM calls into fput and thus
> ->release with the mmap_sem held, which makes it really hard for a
> filesystem to avoid a lock inversion if it uses a lock both in ->release
> and the I/O path.
> 
> I have a workaround for this to only acquire the XFS iolock with a
> trylock in the release path and leave cleaning up stale preallocations
> until the final iput.  It's not pretty, but given that we're unlikely
> to see the VM fixed I might aswell finally send it for inclusion.
> 

In seems very easy and reliable to reproduce on my machine - so I am happy 
to test the patch here when you're ready.

Thanks

John

      reply	other threads:[~2009-10-11 16:00 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-10 23:09 John Kacur
2009-10-11 12:46 ` [xfs-masters] " Christoph Hellwig
2009-10-11 15:59   ` John Kacur [this message]

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