diff --git a/metropolis/pkg/devicemapper/BUILD.bazel b/metropolis/pkg/devicemapper/BUILD.bazel
index 9e66a7e..e0dca24 100644
--- a/metropolis/pkg/devicemapper/BUILD.bazel
+++ b/metropolis/pkg/devicemapper/BUILD.bazel
@@ -2,7 +2,10 @@
 
 go_library(
     name = "go_default_library",
-    srcs = ["devicemapper.go"],
+    srcs = [
+        "ctype.go",
+        "devicemapper.go",
+    ],
     importpath = "source.monogon.dev/metropolis/pkg/devicemapper",
     visibility = ["//metropolis:__subpackages__"],
     deps = [