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From: Christoph Hellwig <hch@infradead.org>
To: Avi Kivity <avi@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>,
	Anthony Liguori <anthony@codemonkey.ws>,
	Michael Tokarev <mjt@tls.msk.ru>, KVM list <kvm@vger.kernel.org>,
	Kevin Wolf <kwolf@redhat.com>
Subject: Re: JFYI: ext4 bug triggerable by kvm
Date: Tue, 17 Aug 2010 11:04:55 -0400	[thread overview]
Message-ID: <20100817150455.GB19231@infradead.org> (raw)
In-Reply-To: <4C6AA3BB.5020103@redhat.com>

On Tue, Aug 17, 2010 at 05:59:07PM +0300, Avi Kivity wrote:
> I agree, but there's another case: tell the guest that we have a
> write cache, use O_DSYNC, but only flush the disk cache on guest
> flushes.

O_DSYNC flushes the disk write cache and any filesystem that supports
non-volatile cache.   The disk cache is not an abstraction
exposed to applications.

> I believe this can be approximated by mounting the host filesystem
> with barrier=0?

Mounting the host filesystem with nobarrier means we will never explicit
flush the volatile write cache on the disk.

      reply	other threads:[~2010-08-17 15:04 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-16 14:00 JFYI: ext4 bug triggerable by kvm Michael Tokarev
2010-08-16 14:43 ` Anthony Liguori
2010-08-16 18:42   ` Christoph Hellwig
2010-08-16 20:34     ` Anthony Liguori
2010-08-17  9:07       ` Christoph Hellwig
2010-08-17  9:23         ` Avi Kivity
2010-08-17 11:17           ` Christoph Hellwig
2010-08-17 12:56         ` Anthony Liguori
2010-08-17 13:07           ` Christoph Hellwig
2010-08-17 14:20             ` Anthony Liguori
2010-08-17 14:28               ` Christoph Hellwig
2010-08-17 14:39                 ` Anthony Liguori
2010-08-17 14:45                   ` Christoph Hellwig
2010-08-17 14:53                     ` Avi Kivity
2010-08-17 14:54                     ` Anthony Liguori
2010-08-17 15:01                       ` Avi Kivity
2010-08-17 15:02                       ` Christoph Hellwig
2010-08-17 14:40                 ` Michael Tokarev
2010-08-17 14:44                   ` Anthony Liguori
2010-08-17 14:46                     ` Christoph Hellwig
2010-08-17 14:57                       ` Anthony Liguori
2010-08-17 14:59                       ` Avi Kivity
2010-08-17 15:04                         ` Christoph Hellwig [this message]

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