From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1Npjq8-0004Ir-Di for qemu-devel@nongnu.org; Thu, 11 Mar 2010 09:58:20 -0500 Received: from [199.232.76.173] (port=35187 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Npjq7-0004IG-Tm for qemu-devel@nongnu.org; Thu, 11 Mar 2010 09:58:19 -0500 Received: from Debian-exim by monty-python.gnu.org with spam-scanned (Exim 4.60) (envelope-from ) id 1Npjq7-0000Gz-8i for qemu-devel@nongnu.org; Thu, 11 Mar 2010 09:58:19 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42336) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1Npjq6-0000Gs-QC for qemu-devel@nongnu.org; Thu, 11 Mar 2010 09:58:19 -0500 Message-ID: <4B990507.5090101@redhat.com> Date: Thu, 11 Mar 2010 16:58:15 +0200 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [Qemu-devel] [PATCH 0/3]: BLOCK_WATERMARK QMP event References: <1268175216-3600-1-git-send-email-lcapitulino@redhat.com> <4B96D4F1.80405@codemonkey.ws> <4B975B0A.1030502@redhat.com> <4B980D26.8070000@codemonkey.ws> <4B98AB17.8080506@redhat.com> <4B98FBE8.5050708@codemonkey.ws> In-Reply-To: <4B98FBE8.5050708@codemonkey.ws> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Anthony Liguori Cc: Kevin Wolf , uril@redhat.com, qemu-devel@nongnu.org, Luiz Capitulino On 03/11/2010 04:19 PM, Anthony Liguori wrote: > >> But honestly, while I do understand your point, this feels like a hack >> to work around shortcomings of an interface. So what we need to decide >> is which criterion outweighs the other in practice. > > If I understand the use case correctly, what this really boils down to > is that you want to create a growable image on top of a non-growable > device. The management tool then deals with growth using this interface. > > I'm somewhat inclined to suggest that the proper way to support this > is to teach qemu how to grow the LVM volume like it would grow any > normal file. Interesting. Could use a helper or helper.so, or a new block format driver (block/lvm.c). Still, if management is actually interested in the change, not just to grow the volume (perhaps to handle out-of-space, or to check against a global disk low condition), the helper/driver then needs to communicate with the management system, which is awkward. I guess it's workable though. -- error compiling committee.c: too many arguments to function