diff --git a/Volume.h b/Volume.h
index f57ff91..274fb54 100644
--- a/Volume.h
+++ b/Volume.h
@@ -52,6 +52,7 @@
     VolumeManager *mVm;
     bool mDebug;
     int mPartIdx;
+    int mOrigPartIdx;
     bool mRetryMount;
 
     /*
@@ -64,7 +65,7 @@
     virtual ~Volume();
 
     int mountVol();
-    int unmountVol(bool force);
+    int unmountVol(bool force, bool revert);
     int formatVol();
 
     const char *getLabel() { return mLabel; }
@@ -85,6 +86,7 @@
 
     virtual int getDeviceNodes(dev_t *devs, int max) = 0;
     virtual int updateDeviceInfo(char *new_path, int new_major, int new_minor) = 0;
+    virtual void revertDeviceInfo(void) = 0;
     virtual int isDecrypted(void) = 0;
     virtual int getFlags(void) = 0;