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From: Eric Blake <eblake@redhat.com>
To: "Richard W.M. Jones" <rjones@redhat.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH v3] qemu-img: Implement 'diff' operation.
Date: Thu, 17 May 2012 09:49:47 -0600	[thread overview]
Message-ID: <4FB51E1B.9080602@redhat.com> (raw)
In-Reply-To: <1337268840-4779-1-git-send-email-rjones@redhat.com>

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On 05/17/2012 09:34 AM, Richard W.M. Jones wrote:
> From: "Richard W.M. Jones" <rjones@redhat.com>
> 
> This produces a qcow2 file which is the difference between
> two disk images.  ie, if:
> 
>   base.img     - is a disk image (in any format)
>   modified.img - is base.img, copied and modified
> 
> then:
> 
>   qemu-img diff -b base.img modified.img diff.qcow2
> 
> creates 'diff.qcow2' which contains the differences between 'base.img'
> and 'modified.img'.  Note that 'diff.qcow2' has 'base.img' as its
> backing file.
> 
> Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
> Cc: Matthew Booth <mbooth@redhat.com>
> Cc: Pablo Iranzo Gómez <Pablo.Iranzo@redhat.com>
> Cc: Tomas Von Veschler <tvvcox@redhat.com>

Regarding the documentation and command overview:

Reviewed-by: Eric Blake <eblake@redhat.com>

Regarding the actual logic used in computing the diff, I did not closely
look at that, and you would be wise to get a review from someone more
familiar with block dev operations.

-- 
Eric Blake   eblake@redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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  reply	other threads:[~2012-05-17 15:49 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-17 15:34 [Qemu-devel] [PATCH v3] qemu-img: Implement 'diff' operation Richard W.M. Jones
2012-05-17 15:49 ` Eric Blake [this message]
2012-05-21 13:29 ` Kevin Wolf
2012-05-21 13:59   ` Richard W.M. Jones
2012-05-21 14:06     ` Kevin Wolf
2012-05-21 15:30     ` Eric Blake
2012-05-21 15:40       ` Kevin Wolf

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