[Xen-changelog] [qemu-xen staging] xen-block: treat XenbusStateUnknown the same as XenbusStateClosed

[patchbot@xxxxxxx]

commit 4a0ed3588982281db0a2457f51cf6b1630eb7fd0
Author:     Paul Durrant <paul.durrant@xxxxxxxxxx>
AuthorDate: Wed Sep 18 12:57:02 2019 +0100
Commit:     Anthony PERARD <anthony.perard@xxxxxxxxxx>
CommitDate: Fri Sep 27 11:21:35 2019 +0100

    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@xxxxxxxxxx>
    Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
    Acked-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
    Reviewed-by: John Snow <jsnow@xxxxxxxxxx>
    Message-Id: <20190918115702.38959-1-paul.durrant@xxxxxxxxxx>
    Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
    (cherry picked from commit ef916ab3ec570eac799be540e499d0123fe61899)
---
 hw/block/xen-block.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/block/xen-block.c b/hw/block/xen-block.c
index 69d73196e2..ed54db74ad 100644
--- a/hw/block/xen-block.c
+++ b/hw/block/xen-block.c
@@ -312,6 +312,7 @@ 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);
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#staging

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