block: Connect BlockBackend to BlockDriverState

Convenience function blk_new_with_bs() creates a BlockBackend with its
BlockDriverState.  Callers have to unref both.  The commit after next
will relieve them of the need to unref the BlockDriverState.

Complication: due to the silly way drive_del works, we need a way to
hide a BlockBackend, just like bdrv_make_anon().  To emphasize its
"special" status, give the function a suitably off-putting name:
blk_hide_on_behalf_of_do_drive_del().  Unfortunately, hiding turns the
BlockBackend's name into the empty string.  Can't avoid that without
breaking the blk->bs->device_name equals blk->name invariant.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/qemu-io.c b/qemu-io.c
index a8dc973..8380734 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -62,8 +62,8 @@ static int openfile(char *name, int flags, int growable, QDict *opts)
         return 1;
     }
 
-    qemuio_blk = blk_new("hda", &error_abort);
-    qemuio_bs = bdrv_new_root("hda", &error_abort);
+    qemuio_blk = blk_new_with_bs("hda", &error_abort);
+    qemuio_bs = blk_bs(qemuio_blk);
 
     if (growable) {
         flags |= BDRV_O_PROTOCOL;