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Date: Mon, 20 May 2013 09:23:43 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v3 0/8] block: drive-backup live backup
	command
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To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Fam Zheng <famz@redhat.com>, qemu-devel <qemu-devel@nongnu.org>, Dietmar Maurer <dietmar@proxmox.com>, imain@redhat.com, Stefan Hajnoczi <stefanha@redhat.com>, Wenchao Xia <xiawenc@linux.vnet.ibm.com>

Il 20/05/2013 08:24, Stefan Hajnoczi ha scritto:
>> > You only need to fdatasync() before every guest flush, no?
> No, you need to set the dirty bit before issuing the write on the
> host.  Otherwise the image data may be modified without setting the
> appropriate dirty bit.  That would allow data modifications to go
> undetected!

But data modifications can go undetected until the guest flush returns,
can't they?

Paolo