block: Allow reference for bdrv_file_open()

Allow specifying a reference to an existing block device (by name) for
bdrv_file_open() instead of a filename and/or options.

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

1 files changed, 1 insertions, 1 deletions

diff --git a/block/qcow2.c b/block/qcow2.c
index 8ec9db10f8..e15a4dd057 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1483,7 +1483,7 @@ static int qcow2_create2(const char *filename, int64_t total_size,
         return ret;
     }
 
-    ret = bdrv_file_open(&bs, filename, NULL, BDRV_O_RDWR, &local_err);
+    ret = bdrv_file_open(&bs, filename, NULL, NULL, BDRV_O_RDWR, &local_err);
     if (ret < 0) {
         error_propagate(errp, local_err);
         return ret;