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From: Christoph Hellwig <hch@lst.de>
To: John Kacur <jkacur@redhat.com>
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 14:46:16 +0200	[thread overview]
Message-ID: <20091011124616.GA4081@lst.de> (raw)
In-Reply-To: <alpine.LFD.2.00.0910110108160.4921@localhost.localdomain>

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.


  reply	other threads:[~2009-10-11 12:47 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 ` Christoph Hellwig [this message]
2009-10-11 15:59   ` [xfs-masters] " John Kacur

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