This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


Re: [Xen-devel] domU oom -> xvda1 read-only without any notice?

To: Josip Rodin <joy@xxxxxxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] domU oom -> xvda1 read-only without any notice?
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Wed, 31 Mar 2010 08:43:07 +0100
Delivery-date: Wed, 31 Mar 2010 00:43:51 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <20100331073340.GA13507@xxxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcrQpKIQi6DkbsuTR56STPlY3FnPRQAASt66
Thread-topic: [Xen-devel] domU oom -> xvda1 read-only without any notice?
User-agent: Microsoft-Entourage/
On 31/03/2010 08:33, "Josip Rodin" <joy@xxxxxxxxxxxxxx> wrote:

> % sudo mount -o remount,rw /
> mount: block device /dev/xvda1 is write-protected, mounting read-only
> There are no messages in the kernel log on either the .32 domU or the .26
> dom0. What do I do, other than shutdown and re-create? How does one manually
> 'talk' to blkback to see what's up?

Blkback communicates this kind of info to blkfront via a node in xenstore
named 'info'. Bit 2 of this numeric field indicates if a virtual disc is
read-only. I think it's more likely that the domU has internally confused
itself, rather than being told to mount read-only by dom0 -- the flags get
probed when the virtual disc first appears, and I don't think would get
probed again after that anyway without a full disc hot-unplug/replug.

 -- Keir

Xen-devel mailing list