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Date: Tue, 9 Sep 2014 10:21:54 +0200
From: Kevin Wolf <kwolf@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH v2] qcow2: add update refcount table
 realization for update_refcount
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To: Jun Li <junmuzi@gmail.com>
Cc: famz@redhat.com, juli@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com

Am 09.09.2014 um 04:52 hat Jun Li geschrieben:
> On Fri, 09/05 12:21, Kevin Wolf wrote:
> > Am 01.09.2014 um 12:52 hat Jun Li geschrieben:
> > > When every item of refcount block is NULL, free refcount block and reset the
> > > corresponding item of refcount table with NULL.
> > > 
> > > Signed-off-by: Jun Li <address@hidden>
> > 
> > The commit message should also describe why this is a relevant
> > improvement for some use case. My gut feeling is that it complicates the
> > code for a very minimal gain.
> 
> Hi Kevin,
>   
>   "Add update refcount table realization for update_refcount" is nesseary for
>   qcow2 shrinking. I will submit v3 of "qcow2: Patch for shrinking qcow2 disk
>   image". When check the code of update_refcount, I find it lacks of this patch.

Why is it necessary? Can't you just leave the refcount blocks allocated?
They shouldn't take a lot of space.

Kevin