block: make .bdrv_close optional

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

2 files changed, 6 insertions, 2 deletions

diff --git a/block.c b/block.c
index 39f373e035..9694018a68 100644
--- a/block.c
+++ b/block.c
@@ -3349,7 +3349,9 @@ static void bdrv_close(BlockDriverState *bs)
     bdrv_drain(bs); /* in case flush left pending I/O */
 
     if (bs->drv) {
-        bs->drv->bdrv_close(bs);
+        if (bs->drv->bdrv_close) {
+            bs->drv->bdrv_close(bs);
+        }
         bs->drv = NULL;
     }
 
diff --git a/block/snapshot.c b/block/snapshot.c
index f9903bc94e..3218a542df 100644
--- a/block/snapshot.c
+++ b/block/snapshot.c
@@ -218,7 +218,9 @@ int bdrv_snapshot_goto(BlockDriverState *bs,
         qobject_unref(file_options);
         qdict_put_str(options, "file", bdrv_get_node_name(file));
 
-        drv->bdrv_close(bs);
+        if (drv->bdrv_close) {
+            drv->bdrv_close(bs);
+        }
         bdrv_unref_child(bs, bs->file);
         bs->file = NULL;