From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46093) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YQ9FQ-0005mD-GZ for qemu-devel@nongnu.org; Tue, 24 Feb 2015 01:45:37 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YQ9FN-0005U9-4H for qemu-devel@nongnu.org; Tue, 24 Feb 2015 01:45:36 -0500 Received: from mx-v6.kamp.de ([2a02:248:0:51::16]:39394 helo=mx01.kamp.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YQ9FM-0005U5-N6 for qemu-devel@nongnu.org; Tue, 24 Feb 2015 01:45:33 -0500 Message-ID: <54EC1E08.4030205@kamp.de> Date: Tue, 24 Feb 2015 07:45:28 +0100 From: Peter Lieven MIME-Version: 1.0 References: <1424701661-21241-1-git-send-email-pl@kamp.de> <1424701661-21241-4-git-send-email-pl@kamp.de> <54EB72B9.108@redhat.com> In-Reply-To: <54EB72B9.108@redhat.com> Content-Type: text/plain; charset=iso-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 3/5] vpc: Ignore geometry for large images List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Max Reitz , qemu-devel@nongnu.org Cc: kwolf@redhat.com, carnold@suse.com, jcody@redhat.com, stefanha@redhat.com Am 23.02.2015 um 19:34 schrieb Max Reitz: > On 2015-02-23 at 09:27, Peter Lieven wrote: >> From: Kevin Wolf >> >> The CHS calculation as done per the VHD spec imposes a maximum image >> size of ~127 GB. Real VHD images exist that are larger than that. >> >> Apparently there are two separate non-standard ways to achieve this: >> You could use more heads than the spec does - this is the option that >> qemu-img create chooses. >> >> However, other images exist where the geometry is set to the maximum >> (65536/16/255), but the actual image size is larger. Until now, such >> images are truncated at 127 GB when opening them with qemu. >> >> This patch changes the vpc driver to ignore geometry in this case and >> only trust the size field in the header. >> >> Signed-off-by: Kevin Wolf >> --- >> block/vpc.c | 10 ++++------ >> 1 file changed, 4 insertions(+), 6 deletions(-) > > I'm trusting you this works for disk2vhd; at least it's in accordance with the VHD specification. When I wrote the hack for disk2vhd some time ago I just found that the reported size was too big. I was not aware that it was exactly this special value. You say in the specs. Do you have a spec that is actually stating that (65536/16/255) is special value that says ignore CHS and look at the footer? Peter