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Re: [Xen-devel] [PATCH] Safely finish closing protocol when guest fails in blkfront

On Tue, Dec 05, 2006 at 07:39:11AM +0000, Keir Fraser wrote:
> On 4/12/06 9:40 pm, "Glauber de Oliveira Costa" <gcosta@xxxxxxxxxx> wrote:
> > If a guest finds any error and aborts the connection of a block device,
> > it's online state set at device create phase will stop it from being
> > properly cleaned up.
> > 
> > Follows a fix for it.
> Assignment and unassignment of physical resources is really a tools issue.
> Tools should really be integrated with device-hotplug success/failure anyway
> -- for example, it is likely the initiator would like confirmation of
> success/failure in most cases.
Agree. But what if after properly initiation, frontend finds an error
and starts Closing protocol? What will happen is that the test

        if (xenbus_dev_is_online(dev))

will cause the device to not be unregistered. At this point, it do not
see frontend changes. (putting backend in closing leads to frontend
closing,closed, but backend never see frontend closing, never going to

Given that, what tools can do ? At the current point, this is what leads
me to believe that arbitrary frontend-failure cases should be handled in the 

Glauber de Oliveira Costa
Red Hat Inc.
"Free as in Freedom"

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