[Xen-changelog] [qemu-xen master] block-backend: Always notify on blk_eject

[patchbot@xxxxxxx]

commit c47ee043dc2cc85da710e87524144a720598c096
Author:     John Snow <jsnow@xxxxxxxxxx>
AuthorDate: Mon Nov 14 11:15:54 2016 -0500
Commit:     John Snow <jsnow@xxxxxxxxxx>
CommitDate: Mon Nov 14 11:15:54 2016 -0500

    block-backend: Always notify on blk_eject
    
    blk_eject is only used by scsi-disk and atapi, and in both cases we
    only attempt to invoke blk_eject if we have a bona-fide change in
    tray state.
    
    The "issue" here is that the tray state does not generate a QMP event
    unless there is a medium/BDS attached to the device, so if libvirt et al
    are waiting for a tray event to occur from an empty-but-closed drive,
    software opening that drive will not emit an event and libvirt will
    wait forever.
    
    Change this by modifying blk_eject to always emit an event, instead of
    conditionally on a "real" backend eject.
    
    Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1373264
    
    Reported-by: Peter Krempa <pkrempa@xxxxxxxxxx>
    Signed-off-by: John Snow <jsnow@xxxxxxxxxx>
    Reviewed-by: Eric Blake <eblake@xxxxxxxxxx>
    Reviewed-by: Kevin Wolf <kwolf@xxxxxxxxxx>
    Message-id: 1478553214-497-2-git-send-email-jsnow@xxxxxxxxxx
    Signed-off-by: John Snow <jsnow@xxxxxxxxxx>
---
 block/block-backend.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/block/block-backend.c b/block/block-backend.c
index 27a7f6f..efbf398 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1393,13 +1393,14 @@ void blk_eject(BlockBackend *blk, bool eject_flag)
 
     if (bs) {
         bdrv_eject(bs, eject_flag);
-
-        id = blk_get_attached_dev_id(blk);
-        qapi_event_send_device_tray_moved(blk_name(blk), id,
-                                          eject_flag, &error_abort);
-        g_free(id);
-
     }
+
+    /* Whether or not we ejected on the backend,
+     * the frontend experienced a tray event. */
+    id = blk_get_attached_dev_id(blk);
+    qapi_event_send_device_tray_moved(blk_name(blk), id,
+                                      eject_flag, &error_abort);
+    g_free(id);
 }
 
 int blk_get_flags(BlockBackend *blk)
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#master

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