xen-block: treat XenbusStateUnknown the same as XenbusStateClosed

When a frontend gracefully disconnects from an offline backend, it will
set its own state to XenbusStateClosed. The code in xen-block.c correctly
deals with this and sets the backend into XenbusStateClosed. Unfortunately
it is possible for toolstack to actually delete the frontend area
before the state key has been read, leading to an apparent frontend state
of XenbusStateUnknown. This prevents the backend state from transitioning
to XenbusStateClosed and hence leaves it limbo.

This patch simply treats a frontend state of XenbusStateUnknown the same
as XenbusStateClosed, which will unblock the backend in these circumstances.

Reported-by: Mark Syms <mark.syms@citrix.com>
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Message-Id: <20190918115702.38959-1-paul.durrant@citrix.com>
Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
This commit is contained in:
Paul Durrant 2019-09-18 12:57:02 +01:00 committed by Anthony PERARD
parent 784e9727af
commit ef916ab3ec

View File

@ -313,6 +313,7 @@ static void xen_block_frontend_changed(XenDevice *xendev,
break;
case XenbusStateClosed:
case XenbusStateUnknown:
xen_block_disconnect(xendev, &local_err);
if (local_err) {
error_propagate(errp, local_err);