From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54628) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1anSxe-000608-BH for qemu-devel@nongnu.org; Tue, 05 Apr 2016 11:32:11 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1anSxb-00073B-2C for qemu-devel@nongnu.org; Tue, 05 Apr 2016 11:32:10 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45350) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1anSxa-000737-TM for qemu-devel@nongnu.org; Tue, 05 Apr 2016 11:32:07 -0400 References: <1459787950-15286-1-git-send-email-eblake@redhat.com> <7AD0DCB1-1868-4AAD-A03D-C976A728DD75@alex.org.uk> <5702C1AB.8020601@redhat.com> <5702C65A.7040101@openvz.org> <48C4F50D-E826-40E7-BB4F-21F9D1A67386@alex.org.uk> <5703C880.1060007@redhat.com> <5703D866.4020907@redhat.com> <8DC2DC6C-0CCD-4C03-B2CF-023E13D52B80@alex.org.uk> From: Paolo Bonzini Message-ID: <5703DA6F.4030802@redhat.com> Date: Tue, 5 Apr 2016 17:31:59 +0200 MIME-Version: 1.0 In-Reply-To: <8DC2DC6C-0CCD-4C03-B2CF-023E13D52B80@alex.org.uk> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [Nbd] [PATCH v2] doc: Add NBD_CMD_BLOCK_STATUS extension List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alex Bligh Cc: "nbd-general@lists.sourceforge.net" , Kevin Wolf , "qemu-devel@nongnu.org" , Pavel Borzenkov , "Stefan stefanha@redhat. com" , Wouter Verhelst , "Denis V. Lunev" On 05/04/2016 17:27, Alex Bligh wrote: >>> I'm missing how the ugh-author can write the software without knowing >>> exactly what the bit does. Or are you saying "that's a matter >>> for the qemu spec, not the nbd spec"? > > > > Yes, that's it. NBD defines a safe default and a general idea of what > > it should be used for. > > OK, so my argument then is we should not have a special case > 'only Qemu knows what this does' bit if we can avoid at, and > instead have a general system of 'proprietary bits' (unfortunate > word but perhaps 'non-NBD'). I think it is generic enough. Ideally the backup software wouldn't see the QEMU-specific bits, those would be provided by a management layer (such as OpenStack/Virtuozzo/oVirt/ProxMox). They would just know to copy the dirty bits. Paolo