From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43641) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XOwbL-0006oE-AI for qemu-devel@nongnu.org; Tue, 02 Sep 2014 18:31:04 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XOwbD-0003aP-W2 for qemu-devel@nongnu.org; Tue, 02 Sep 2014 18:30:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:38665) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XOwbD-0003aJ-M5 for qemu-devel@nongnu.org; Tue, 02 Sep 2014 18:30:51 -0400 Message-ID: <54064517.9000104@redhat.com> Date: Tue, 02 Sep 2014 16:30:47 -0600 From: Eric Blake MIME-Version: 1.0 References: <1409696709-27623-1-git-send-email-mreitz@redhat.com> <1409696709-27623-4-git-send-email-mreitz@redhat.com> In-Reply-To: <1409696709-27623-4-git-send-email-mreitz@redhat.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="vkIEIrskbnjBBbxCDoctksNS1kWWigFQK" Subject: Re: [Qemu-devel] [PATCH v2 3/3] docs/qcow2: Limit refcount_order to [0, 6] List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Max Reitz , qemu-devel@nongnu.org Cc: Kevin Wolf , =?UTF-8?B?QmVub8OudCBDYW5ldA==?= , Stefan Hajnoczi This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --vkIEIrskbnjBBbxCDoctksNS1kWWigFQK Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 09/02/2014 04:25 PM, Max Reitz wrote: > Specify the upper limit of refcount_order to be 6 (that is, > refcount_bits =3D 64). Any larger value does not make much sense when a= ll > offsets, sizes, cluster counts etc. "only" have a width of 64 bit as > well, and very large values would be very difficult to support. > Therefore, just cap it at the largest reasonable value. >=20 > Suggested-by: Eric Blake > Signed-off-by: Max Reitz > --- > docs/specs/qcow2.txt | 1 + > 1 file changed, 1 insertion(+) Reviewed-by: Eric Blake >=20 > diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt > index 0a878aa..121dfc8 100644 > --- a/docs/specs/qcow2.txt > +++ b/docs/specs/qcow2.txt > @@ -110,6 +110,7 @@ in the description of a field. > in bits: refcount_bits =3D 1 << refcount_order). F= or version 2 > images, the order is always assumed to be 4 > (i.e. refcount_bits =3D 16). > + This value may not exceed 6 (i.e. refcount_bits =3D= 64). > =20 > 100 - 103: header_length > Length of the header structure in bytes. For versi= on 2 >=20 --=20 Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org --vkIEIrskbnjBBbxCDoctksNS1kWWigFQK Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Public key at http://people.redhat.com/eblake/eblake.gpg iQEcBAEBCAAGBQJUBkUXAAoJEKeha0olJ0NqPaQH/igAal2Q5Srfec9bxgytLuc1 jEoifyRT6Dm0FwToEkpvVzSVNzCFBALTjcg+T5lJ6hNCx46t6DiapVX7T1N59iDm f6vXorRu/dGl6yT7M/zXLsep5N7YmRge4mxODMghBxaD6Nq2G8bG+2Yxv21nP7OS qzjVTg21JuORdlqiIarVsEHPt53IioLcB6ShUPMCpzukTtPYel+eUfWfveR/jrbC UosVzNFA0Fd5r61jyzR8OLkfc5vJY40JA9z/8wVcLVR7wqa1MAb7PJPnvB6VwQZM KGlFvviY1iMMDh5giM8JYMrAC7NW5g/AfUFJT24+GXj9t302tYH4f7lUDswvT8M= =VtU0 -----END PGP SIGNATURE----- --vkIEIrskbnjBBbxCDoctksNS1kWWigFQK--