From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43)
	id 1NcHhk-00060h-Kq
	for qemu-devel@nongnu.org; Tue, 02 Feb 2010 07:18:04 -0500
Received: from [199.232.76.173] (port=60718 helo=monty-python.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1NcHhj-0005zH-Vb
	for qemu-devel@nongnu.org; Tue, 02 Feb 2010 07:18:04 -0500
Received: from Debian-exim by monty-python.gnu.org with spam-scanned (Exim
	4.60) (envelope-from <lcapitulino@redhat.com>) id 1NcHhG-0005L3-S1
	for qemu-devel@nongnu.org; Tue, 02 Feb 2010 07:18:03 -0500
Received: from mx1.redhat.com ([209.132.183.28]:31788)
	by monty-python.gnu.org with esmtp (Exim 4.60)
	(envelope-from <lcapitulino@redhat.com>) id 1NcHhF-0005KL-R0
	for qemu-devel@nongnu.org; Tue, 02 Feb 2010 07:17:34 -0500
Received: from int-mx02.intmail.prod.int.phx2.redhat.com
	(int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12])
	by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o12CHVhk023671
	(version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK)
	for <qemu-devel@nongnu.org>; Tue, 2 Feb 2010 07:17:32 -0500
Date: Tue, 2 Feb 2010 10:17:23 -0200
From: Luiz Capitulino <lcapitulino@redhat.com>
Message-ID: <20100202101723.291a57f2@doriath>
In-Reply-To: <4B67EF7F.8060308@redhat.com>
References: <1265047668-15039-1-git-send-email-lcapitulino@redhat.com>
	<4B67EF7F.8060308@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Subject: [Qemu-devel] Re: [RFC 0/2]: QMP DISK_ERROR event
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.gnu.org/pipermail/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-devel@nongnu.org

On Tue, 02 Feb 2010 10:25:19 +0100
Kevin Wolf <kwolf@redhat.com> wrote:

> Hi Luiz,
> 
> Am 01.02.2010 19:07, schrieb Luiz Capitulino:
> >  Hi there,
> > 
> >  I've been requested by libvirt guys to add a QMP event for disk I/O errors,
> > this is what this series is about.
> > 
> >  It's a RFC because I need feedback on the following:
> > 
> > 1. drive_get_on_error() is called on all disk errors, right?
> 
> Well, yes, it is for all devices that support rerror/werror. But it also
> might be called in other situations. Look at the "get" in the function
> name, it's really a getter function and not a event handler.
> 
> > 2. I've tested only ENOSPC errors, is there a way to test other errors? Like
> > read ones?
> 
> So you'll probably want some EIO. Some recent bugs I've been handling
> were a about images on NFS when the NFS server want away. It's a
> reliable way to get EIO (mount with -osoft and small timeouts). I guess
> qemu-nbd and the nbd: protocol might work, too.
> 
> Or maybe copy the start of a qcow2 image to a too small device.

 Thanks!

> > 3. Is this the right approach at all? :)
> 
> Yes and no. As I said above, drive_get_on_error() is not the right place
> to do it. Unfortunately it looks like there isn't a single generic place
> where it can be done, but the call to the event handler must be added to
> every device.

 Can't it be added to subsystems? Like ide, virtio etc?

 Maybe in the same function that calls driver_get_on_error()?