diff --git a/VoldNativeService.h b/VoldNativeService.h
index 8fd6261..47991c2 100644
--- a/VoldNativeService.h
+++ b/VoldNativeService.h
@@ -66,6 +66,8 @@
     binder::Status remountUid(int32_t uid, int32_t remountMode);
     binder::Status remountAppStorageDirs(int uid, int pid,
                                const std::vector<std::string>& packageNames);
+    binder::Status unmountAppStorageDirs(int uid, int pid,
+                               const std::vector<std::string>& packageNames);
 
     binder::Status ensureAppDirsCreated(const std::vector<std::string>& paths, int32_t appUid);
     binder::Status setupAppDir(const std::string& path, int32_t appUid);