From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:40278) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XcZJr-0000qO-1K for qemu-devel@nongnu.org; Fri, 10 Oct 2014 08:29:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XcZJk-0000le-ST for qemu-devel@nongnu.org; Fri, 10 Oct 2014 08:29:14 -0400 Received: from dew.nodalink.com ([95.130.14.197]:40432) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XcZJk-0000lK-Ml for qemu-devel@nongnu.org; Fri, 10 Oct 2014 08:29:08 -0400 Date: Fri, 10 Oct 2014 12:29:28 +0000 From: =?iso-8859-1?Q?Beno=EEt?= Canet Message-ID: <20141010122928.GD22893@nodalink.com> References: <1409348463-16627-1-git-send-email-mreitz@redhat.com> <1409348463-16627-2-git-send-email-mreitz@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <1409348463-16627-2-git-send-email-mreitz@redhat.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v5 01/11] qcow2: Calculate refcount block entry count List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Max Reitz Cc: Kevin Wolf , Stefan Hajnoczi , qemu-devel@nongnu.org, =?iso-8859-1?Q?Beno=EEt?= Canet On Fri, Aug 29, 2014 at 11:40:53PM +0200, Max Reitz wrote: > The size of a refblock entry is (in theory) variable; calculate > therefore the number of entries per refblock and the according bit shif= t > (1 << x =3D=3D entry count) when opening an image. >=20 > Signed-off-by: Max Reitz > --- > block/qcow2.c | 2 ++ > block/qcow2.h | 2 ++ > 2 files changed, 4 insertions(+) >=20 > diff --git a/block/qcow2.c b/block/qcow2.c > index f9e045f..172ad00 100644 > --- a/block/qcow2.c > +++ b/block/qcow2.c > @@ -689,6 +689,8 @@ static int qcow2_open(BlockDriverState *bs, QDict *= options, int flags, > =20 > s->l2_bits =3D s->cluster_bits - 3; /* L2 is always one cluster */ > s->l2_size =3D 1 << s->l2_bits; > + s->refcount_block_bits =3D s->cluster_bits - (s->refcount_order - = 3); After carefull examination (s->refcount_order - 3) =3D=3D REFCOUNT_SHIFT. Why not also creating s->refcount_shift and make use of it in order to av= oid torturing the mind of the next reader. Or simply recall in a comment that there is 2^3 bits in a byte. Best regards Beno=EEt > + s->refcount_block_size =3D 1 << s->refcount_block_bits; > bs->total_sectors =3D header.size / 512; > s->csize_shift =3D (62 - (s->cluster_bits - 8)); > s->csize_mask =3D (1 << (s->cluster_bits - 8)) - 1; > diff --git a/block/qcow2.h b/block/qcow2.h > index 6aeb7ea..7c01fb7 100644 > --- a/block/qcow2.h > +++ b/block/qcow2.h > @@ -222,6 +222,8 @@ typedef struct BDRVQcowState { > int l2_size; > int l1_size; > int l1_vm_state_index; > + int refcount_block_bits; > + int refcount_block_size; > int csize_shift; > int csize_mask; > uint64_t cluster_offset_mask; > --=20 > 2.1.0 >=20