From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35662) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XrqC0-0000Fm-AP for qemu-devel@nongnu.org; Fri, 21 Nov 2014 10:32:22 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XrqBu-0006d2-LQ for qemu-devel@nongnu.org; Fri, 21 Nov 2014 10:32:16 -0500 Received: from mx4-phx2.redhat.com ([209.132.183.25]:59152) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XrqBu-0006ch-F9 for qemu-devel@nongnu.org; Fri, 21 Nov 2014 10:32:10 -0500 Date: Fri, 21 Nov 2014 10:32:06 -0500 (EST) From: Francesco Romani Message-ID: <781769647.2018010.1416583926495.JavaMail.zimbra@redhat.com> In-Reply-To: <20141121101126.GA3956@noname.redhat.com> References: <1415365933-3727-1-git-send-email-fromani@redhat.com> <1415365933-3727-2-git-send-email-fromani@redhat.com> <20141117164936.GL16192@stefanha-thinkpad.redhat.com> <20141120103053.GA9266@noname.redhat.com> <20141120110456.GA11224@stefanha-thinkpad.redhat.com> <20141120113428.GB9266@noname.redhat.com> <21397425.1869233.1416559420438.JavaMail.zimbra@redhat.com> <20141121101126.GA3956@noname.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [RFC][PATCH v2] block: add write threshold reporting for block devices List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Kevin Wolf Cc: Stefan Hajnoczi , Luiz Capitulino , qemu-devel@nongnu.org, Stefan Hajnoczi , mdroth@linux.vnet.ibm.com ----- Original Message ----- > From: "Kevin Wolf" > To: "Francesco Romani" > Cc: qemu-devel@nongnu.org, "Stefan Hajnoczi" , mdroth@linux.vnet.ibm.com, "Luiz Capitulino" > , "Stefan Hajnoczi" > Sent: Friday, November 21, 2014 11:11:26 AM > Subject: Re: [Qemu-devel] [RFC][PATCH v2] block: add write threshold reporting for block devices [...] > > 1. I'm running a simple test using the attached script - > > which is a qemu command line adapted from libvirt ouput driven > > by oVirt. There is a way to attach a name at this stage, using a QMP > > command? > > No, node-name is assigned at the BlockDriverState (BDS) creation and > can't be changed later on. Makes sense to me. > > 2. (related to the former) it seems from a not-so-deep look that the > > blessed (only?) > > way to set a proper node_name is using blockdev-add. > > If so, I'm not sure I follow how the qemu boot flow would look like. > > It will not be anymore as simple as crafting a command line and run the > > qemu, right? > > IIUC some interaction with QMP will be needed (sorry for asking silly > > question, > > trying to fill gaps in my knowledge). > > -drive on the command line can do everything that blockdev-add can do. > So let's assume you have a qcow2 image on a filesystem. Then you end up > with two BDSes, one for the format driver and one for accessing the > filesystem: > > BlockBackend (virtual device) -> qcow2 BDS -> file BDS (raw-posix.c) > > For assigning a node name to the qcow2 BDS, you simply specify it in the > obvious way: > > -drive file=test.qcow2,node-name=foo > > Now if you want to assign a node name to the file BDS as well, you would > get nested dicts in the blockdev-add call. In -drive a dot syntax is > used to represent this: > > -drive file=test.qcow2,node-name=foo,file.node-name=bar > > Are things a bit clearer with this? Yes, thanks a lot. I was a bit misleaded by the lack of the reference (after a very quick look) in the man page. Maybe the manpage is out of date, but this is a different story -and maybe a different patch :) New revision will come in a few days. Bests, -- Francesco Romani RedHat Engineering Virtualization R & D Phone: 8261328 IRC: fromani