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From: Eric Blake <eblake@redhat.com>
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Date: Thu, 6 Aug 2015 21:34:52 -0600
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Subject: Re: [Qemu-devel] [PATCH v9 08/10] qcow2: Invoke refcount order
	amendment function
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To: Alberto Garcia <berto@igalia.com>, Max Reitz <mreitz@redhat.com>, qemu-block@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>, qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>

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On 08/06/2015 09:10 AM, Alberto Garcia wrote:
> On Mon 27 Jul 2015 05:51:38 PM CEST, Max Reitz wrote:
>=20
>> +            if (refcount_bits <=3D 0 || refcount_bits > 64 ||
>> +                !is_power_of_2(refcount_bits))
>> +            {
>> +                error_report("Refcount width must be a power of two a=
nd may "
>> +                             "not exceed 64 bits");
>> +                return -EINVAL;
>> +            }
>=20
> I guess there's no lower limit needed for this? Doesn't it break
> anything if refcount_bits =3D=3D 1?

refcount_bits =3D=3D 1 works just fine - you have an image that can't tak=
e
internal snapshots, and has a maximally dense refblock.


--=20
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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