1 files changed, 4 insertions, 0 deletions
diff --git a/block/block-backend.c b/block/block-backend.c
index e578a2d5e3..048f48e935 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -148,6 +148,8 @@ BlockBackend *blk_new_open(const char *filename, const char *reference,
     BlockBackend *blk;
     int ret;
 
+    assert((flags & BDRV_O_CACHE_WB) == 0);
+
     blk = blk_new_with_bs(errp);
     if (!blk) {
         QDECREF(options);
@@ -160,6 +162,8 @@ BlockBackend *blk_new_open(const char *filename, const char *reference,
         return NULL;
     }
 
+    blk_set_enable_write_cache(blk, true);
+
     return blk;
 }