diff --git a/qemu-io.c b/qemu-io.c
index 72fee0d8b7..73c638ff8b 100644
--- a/qemu-io.c
+++ b/qemu-io.c
@@ -95,12 +95,12 @@ static int openfile(char *name, int flags, bool writethrough, bool force_share,
             opts = qdict_new();
         }
         if (qdict_haskey(opts, BDRV_OPT_FORCE_SHARE)
-            && !qdict_get_bool(opts, BDRV_OPT_FORCE_SHARE)) {
+            && strcmp(qdict_get_str(opts, BDRV_OPT_FORCE_SHARE), "on")) {
             error_report("-U conflicts with image options");
             qobject_unref(opts);
             return 1;
         }
-        qdict_put_bool(opts, BDRV_OPT_FORCE_SHARE, true);
+        qdict_put_str(opts, BDRV_OPT_FORCE_SHARE, "on");
     }
     qemuio_blk = blk_new_open(name, NULL, opts, flags, &local_err);
     if (!qemuio_blk) {