@@ -3434,7 +3434,13 @@ int bdrv_reopen_prepare(BDRVReopenState *reopen_state, BlockReopenQueue *queue,
drv_prepared = true;
- if (drv->supports_backing && reopen_state->backing_missing) {
+ /*
+ * We must provide the 'backing' option if the BDS has a backing
+ * file or if the image file has a backing file name as part of
+ * its metadata. Otherwise the 'backing' option can be omitted.
+ */
+ if (drv->supports_backing && reopen_state->backing_missing &&
+ (backing_bs(reopen_state->bs) || reopen_state->bs->backing_file[0])) {
error_setg(errp, "backing is missing for '%s'",
reopen_state->bs->node_name);
ret = -EINVAL;