From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [140.186.70.92] (port=33541 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Pwwz8-0000iz-EZ for qemu-devel@nongnu.org; Tue, 08 Mar 2011 08:29:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Pwwz7-0006kS-Cp for qemu-devel@nongnu.org; Tue, 08 Mar 2011 08:29:58 -0500 Received: from mx1.redhat.com ([209.132.183.28]:9459) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Pwwz7-0006kF-2d for qemu-devel@nongnu.org; Tue, 08 Mar 2011 08:29:57 -0500 Message-ID: <4D762FCE.7060808@redhat.com> Date: Tue, 08 Mar 2011 14:31:58 +0100 From: Kevin Wolf MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH] Add qcow2 documentation References: <1299584839-5688-1-git-send-email-kwolf@redhat.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: qemu-devel@nongnu.org Am 08.03.2011 14:13, schrieb Stefan Hajnoczi: > On Tue, Mar 8, 2011 at 11:47 AM, Kevin Wolf wrote: >> + 20 - 23: cluster_bits >> + Number of bits that are used for addressing an offset >> + within a cluster (1 << cluster_bits is the cluster size) >> + >> + 24 - 31: size >> + Virtual disk size in bytes > > Any constraints on these two fields that should be mentioned? For the size not that I'm aware of. For cluster_bits qemu restricts it to 512 <= cluster_size <= 2 MB. I think we should add 512 as a lower limit, anything smaller doesn't make sense and steals us bits that we want to use for flags. The 2 MB are more of an implementation limitation. Would you mention it here? The format shouldn't have any problem with larger sizes. Kevin