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From: Paolo Bonzini <pbonzini@redhat.com>
To: Wen Congyang <wency@cn.fujitsu.com>,
	qemu-devl <qemu-devel@nongnu.org>,
	qemu block <qemu-block@nongnu.org>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Jeff Cody <jcody@redhat.com>, Kevin Wolf <kwolf@redhat.com>
Subject: Re: [Qemu-devel] [PATCH] Block: don't do copy-on-read in before_write_notifier
Date: Tue, 18 Aug 2015 22:41:40 -0700	[thread overview]
Message-ID: <55D41714.6030903@redhat.com> (raw)
In-Reply-To: <55D3EFF4.7030004@cn.fujitsu.com>

On 18/08/2015 19:54, Wen Congyang wrote:
> We will copy data in before_write_notifier to do backup.
> It is a nested I/O request, so we cannot do copy-on-read.

Can you explain why?  What is the bug that this is fixing?

Paolo

> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>

  reply	other threads:[~2015-08-19  5:42 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-19  2:54 [Qemu-devel] [PATCH] Block: don't do copy-on-read in before_write_notifier Wen Congyang
2015-08-19  5:41 ` Paolo Bonzini [this message]
2015-08-19  5:43   ` Wen Congyang
2015-08-19 17:02     ` Jeff Cody
2015-08-20  0:46       ` Wen Congyang
2015-09-02 14:18 ` Stefan Hajnoczi
2015-09-02 14:23   ` Jeff Cody
2015-09-03 15:44   ` Kevin Wolf

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