From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LRZRx-0001AV-P6 for qemu-devel@nongnu.org; Mon, 26 Jan 2009 16:56:57 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LRZRx-00019o-4G for qemu-devel@nongnu.org; Mon, 26 Jan 2009 16:56:57 -0500 Received: from [199.232.76.173] (port=39521 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LRZRx-00019g-0D for qemu-devel@nongnu.org; Mon, 26 Jan 2009 16:56:57 -0500 Received: from mail2.shareable.org ([80.68.89.115]:34201) by monty-python.gnu.org with esmtps (TLS-1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1LRZRw-0003Mf-K5 for qemu-devel@nongnu.org; Mon, 26 Jan 2009 16:56:56 -0500 Date: Mon, 26 Jan 2009 21:56:54 +0000 From: Jamie Lokier Subject: Re: [Qemu-devel] [PATCH 0/2] qemu block changes: keep backing file format v2 Message-ID: <20090126215654.GB9296@shareable.org> References: <1232995199-12086-1-git-send-email-uril@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1232995199-12086-1-git-send-email-uril@redhat.com> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Uri Lublin Uri Lublin wrote: > I call "hidden image format" to the following format of a backing file name: > "name\0format". Although it can be considered a hack, that's an easy > way to support old images with new qemu as well as old qemu with new images > (in which case probing would be done), without changing the qcow2 header. ... > Changes from v1: use "name\0format" instead of "fmt:FMT:name" Do you think there will be any other information added in future, while wanting to remain compatible with old qemus (i.e. without changing the qcow2 header)? If so, "name\0format=FMT", and stop at the second \0 if there is one, something like that? -- Jamie