[PATCH 2/2] block/qcow2: zero data_file child after free

[Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>]

data_file being NULL doesn't seem to be a correct state, but it's
better than dead pointer and simpler to debug.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
---
 block/qcow2.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/block/qcow2.c b/block/qcow2.c
index d44b45633d..6cdefe059f 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1758,6 +1758,7 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
     g_free(s->image_data_file);
     if (has_data_file(bs)) {
         bdrv_unref_child(bs, s->data_file);
+        s->data_file = NULL;
     }
     g_free(s->unknown_header_fields);
     cleanup_unknown_header_ext(bs);
@@ -2621,6 +2622,7 @@ static void qcow2_close(BlockDriverState *bs)
 
     if (has_data_file(bs)) {
         bdrv_unref_child(bs, s->data_file);
+        s->data_file = NULL;
     }
 
     qcow2_refcount_close(bs);
-- 
2.21.0