From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:48122) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QoeM2-0001Gz-Aj for qemu-devel@nongnu.org; Wed, 03 Aug 2011 12:31:35 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QoeM1-0006sW-9v for qemu-devel@nongnu.org; Wed, 03 Aug 2011 12:31:34 -0400 Received: from verein.lst.de ([213.95.11.211]:54952 helo=newverein.lst.de) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QoeM1-0006sJ-5U for qemu-devel@nongnu.org; Wed, 03 Aug 2011 12:31:33 -0400 Date: Wed, 3 Aug 2011 18:31:31 +0200 From: Christoph Hellwig Message-ID: <20110803163131.GA8411@lst.de> References: <1312384765-721-1-git-send-email-lcapitulino@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1312384765-721-1-git-send-email-lcapitulino@redhat.com> Subject: Re: [Qemu-devel] [PATCH v2 0/5]: QMP: Proper thin provisioning support List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Luiz Capitulino Cc: kwolf@redhat.com, aliguori@us.ibm.com, qemu-devel@nongnu.org, armbru@redhat.com > It's already possible for QMP clients to implement this feature by using > the BLOCK_IO_ERROR event. However, the event can be missed. When this > happens QMP clients need a way to query if any block device has hit a > no space condition. We have a mode where we stop the VM when it hits ENOSPC, and that is the only reliably way to handle it. One that ENOSPC gets returned to the guest we don't know that it was an ENOSPC, and the guest will usually simply shut the filesystem down. This could be worked around by implementing full T10 logical provisioning support, but very few guests actually support it properly. And it won't work with ide disks at all, and for virtio we'd have to implement it first.