diff --git a/libisofs/ecma119.c b/libisofs/ecma119.c
index 083a288..2dad358 100644
--- a/libisofs/ecma119.c
+++ b/libisofs/ecma119.c
@@ -908,6 +908,11 @@ bs_free_data(struct burn_source *bs)
 		t->state_files.src->close(t->state_files.src);
 }
 
+int bs_set_size(struct burn_source *source, off_t size)
+{
+	return 1;
+}
+	
 struct burn_source *iso_source_new_ecma119(struct iso_volset *volset,
 					    struct ecma119_source_opts *opts)
 {
@@ -915,6 +920,7 @@ struct burn_source *iso_source_new_ecma119(struct iso_volset *volset,
 	ret->refcount = 1;
 	ret->read = bs_read;
 	ret->get_size = bs_get_size;
+	ret->set_size = bs_set_size;
 	ret->free_data = bs_free_data;
 	ret->data = ecma119_target_new(volset, opts);
 	return ret;