diff --git a/libs/storage/Android.mk b/libs/storage/Android.mk
index 7a9dd6c391578..fae2bf7c3457e 100644
--- a/libs/storage/Android.mk
+++ b/libs/storage/Android.mk
@@ -9,4 +9,6 @@ LOCAL_SRC_FILES:= \
 
 LOCAL_MODULE:= libstorage
 
+LOCAL_CFLAGS += -Wall -Werror
+
 include $(BUILD_STATIC_LIBRARY)
diff --git a/libs/storage/IMountService.cpp b/libs/storage/IMountService.cpp
index 621de18b1685e..7ac77378f0c5b 100644
--- a/libs/storage/IMountService.cpp
+++ b/libs/storage/IMountService.cpp
@@ -207,12 +207,19 @@ public:
             ALOGD("getStorageUsers caught exception %d\n", err);
             return err;
         }
-        const int32_t numUsers = reply.readInt32();
+        int32_t numUsersI = reply.readInt32();
+        uint32_t numUsers;
+        if (numUsersI < 0) {
+            ALOGW("Number of users is negative: %d\n", numUsersI);
+            numUsers = 0;
+        } else {
+            numUsers = static_cast<uint32_t>(numUsersI);
+        }
         *users = (int32_t*)malloc(sizeof(int32_t)*numUsers);
-        for (int i = 0; i < numUsers; i++) {
+        for (size_t i = 0; i < numUsers; i++) {
             **users++ = reply.readInt32();
         }
-        return numUsers;
+        return static_cast<int32_t>(numUsers);
     }
 
     int32_t getVolumeState(const String16& mountPoint)
@@ -546,8 +553,8 @@ public:
     }
 };
 
-IMPLEMENT_META_INTERFACE(MountService, "IMountService");
+IMPLEMENT_META_INTERFACE(MountService, "IMountService")
 
 // ----------------------------------------------------------------------
 
-};
+}
diff --git a/libs/storage/IMountServiceListener.cpp b/libs/storage/IMountServiceListener.cpp
index c98a42461b15d..11b53fdc1027a 100644
--- a/libs/storage/IMountServiceListener.cpp
+++ b/libs/storage/IMountServiceListener.cpp
@@ -34,7 +34,7 @@ status_t BnMountServiceListener::onTransact(
             onUsbMassStorageConnectionChanged(connected);
             reply->writeNoException();
             return NO_ERROR;
-        } break;
+        }
         case TRANSACTION_onStorageStateChanged: {
             CHECK_INTERFACE(IMountServiceListener, data, reply);
             String16 path = data.readString16();
@@ -50,4 +50,4 @@ status_t BnMountServiceListener::onTransact(
 }
 // ----------------------------------------------------------------------
 
-};
+}
diff --git a/libs/storage/IMountShutdownObserver.cpp b/libs/storage/IMountShutdownObserver.cpp
index 1a6fdeeac1d92..a74a768409bc4 100644
--- a/libs/storage/IMountShutdownObserver.cpp
+++ b/libs/storage/IMountShutdownObserver.cpp
@@ -33,11 +33,11 @@ status_t BnMountShutdownObserver::onTransact(
             onShutDownComplete(statusCode);
             reply->writeNoException();
             return NO_ERROR;
-        } break;
+        }
         default:
             return BBinder::onTransact(code, data, reply, flags);
     }
 }
 // ----------------------------------------------------------------------
 
-};
+}
diff --git a/libs/storage/IObbActionListener.cpp b/libs/storage/IObbActionListener.cpp
index eaa211ec98ab0..9656e655e22ce 100644
--- a/libs/storage/IObbActionListener.cpp
+++ b/libs/storage/IObbActionListener.cpp
@@ -30,10 +30,11 @@ public:
         : BpInterface<IObbActionListener>(impl)
     { }
 
-    virtual void onObbResult(const String16& filename, const int32_t nonce, const int32_t state) { }
+    virtual void onObbResult(const String16& /* filename */, const int32_t /* nonce */,
+                             const int32_t /* state */) { }
 };
 
-IMPLEMENT_META_INTERFACE(ObbActionListener, "IObbActionListener");
+IMPLEMENT_META_INTERFACE(ObbActionListener, "IObbActionListener")
 
 // ----------------------------------------------------------------------
 
@@ -49,7 +50,7 @@ status_t BnObbActionListener::onTransact(
             onObbResult(filename, nonce, state);
             reply->writeNoException();
             return NO_ERROR;
-        } break;
+        }
         default:
             return BBinder::onTransact(code, data, reply, flags);
     }
@@ -57,4 +58,4 @@ status_t BnObbActionListener::onTransact(
 
 // ----------------------------------------------------------------------
 
-};
+}