diff --git a/src/dotnet/FileSystem.cs b/src/dotnet/FileSystem.cs
index 718cf432..10bb9101 100644
--- a/src/dotnet/FileSystem.cs
+++ b/src/dotnet/FileSystem.cs
@@ -174,32 +174,96 @@ namespace Fsp
             return _FileSystem;
         }
 
-        /* FSP_FILE_SYSTEM_INTERFACE */
-        private static Int32 GetVolumeInfo(
-            IntPtr FileSystem,
+        /* operations */
+        protected virtual Int32 ExceptionHandler(Exception ex)
+        {
+            return STATUS_UNEXPECTED_IO_ERROR;
+        }
+        protected virtual Int32 GetVolumeInfo(
             out VolumeInfo VolumeInfo)
         {
             VolumeInfo = default(VolumeInfo);
             return STATUS_INVALID_DEVICE_REQUEST;
         }
-        private static Int32 SetVolumeLabel(
-            IntPtr FileSystem,
+        protected virtual Int32 SetVolumeLabel(
             String VolumeLabel,
             out VolumeInfo VolumeInfo)
         {
             VolumeInfo = default(VolumeInfo);
             return STATUS_INVALID_DEVICE_REQUEST;
         }
+        protected virtual Int32 GetSecurityByName(
+            String FileName,
+            out UInt32 PFileAttributes/* or ReparsePointIndex */,
+            out GenericSecurityDescriptor SecurityDescriptor)
+        {
+            PFileAttributes = default(UInt32);
+            SecurityDescriptor = default(GenericSecurityDescriptor);
+            return STATUS_INVALID_DEVICE_REQUEST;
+        }
+
+        /* FSP_FILE_SYSTEM_INTERFACE */
+        private static Int32 GetVolumeInfo(
+            IntPtr FileSystem,
+            out VolumeInfo VolumeInfo)
+        {
+            FileSystem self = (FileSystem)Api.FspFileSystemGetUserContext(FileSystem);
+            try
+            {
+                return self.GetVolumeInfo(out VolumeInfo);
+            }
+            catch (Exception ex)
+            {
+                VolumeInfo = default(VolumeInfo);
+                return self.ExceptionHandler(ex);
+            }
+        }
+        private static Int32 SetVolumeLabel(
+            IntPtr FileSystem,
+            String VolumeLabel,
+            out VolumeInfo VolumeInfo)
+        {
+            FileSystem self = (FileSystem)Api.FspFileSystemGetUserContext(FileSystem);
+            try
+            {
+                return self.SetVolumeLabel(VolumeLabel, out VolumeInfo);
+            }
+            catch (Exception ex)
+            {
+                VolumeInfo = default(VolumeInfo);
+                return self.ExceptionHandler(ex);
+            }
+        }
         private static Int32 GetSecurityByName(
             IntPtr FileSystem,
             String FileName,
-            out UInt32 PFileAttributes/* or ReparsePointIndex */,
+            IntPtr PFileAttributes/* or ReparsePointIndex */,
             IntPtr SecurityDescriptor,
-            out UIntPtr PSecurityDescriptorSize)
+            IntPtr PSecurityDescriptorSize)
         {
-            PFileAttributes = default(UInt32);
-            PSecurityDescriptorSize = default(UIntPtr);
             return STATUS_INVALID_DEVICE_REQUEST;
+#if false
+            FileSystem self = (FileSystem)Api.FspFileSystemGetUserContext(FileSystem);
+            GenericSecurityDescriptor GenericSecurityDescriptor = null;
+            Int32 Result;
+            try
+            {
+                Result = self.GetSecurityByName(FileName, out PFileAttributes,
+                    out GenericSecurityDescriptor);
+            }
+            catch (Exception ex)
+            {
+                PFileAttributes = default(UInt32);
+                return self.ExceptionHandler(ex);
+            }
+            if (null != GenericSecurityDescriptor)
+            {
+            }
+            else
+            {
+            }
+            return Result;
+#endif
         }
         private static Int32 Create(
             IntPtr FileSystem,
@@ -334,9 +398,8 @@ namespace Fsp
             IntPtr FileSystem,
             IntPtr FileContext,
             IntPtr SecurityDescriptor,
-            out UIntPtr PSecurityDescriptorSize)
+            IntPtr PSecurityDescriptorSize)
         {
-            PSecurityDescriptorSize = default(UIntPtr);
             return STATUS_INVALID_DEVICE_REQUEST;
         }
         private static Int32 SetSecurity(
diff --git a/src/dotnet/Interop.cs b/src/dotnet/Interop.cs
index 4e21c9f5..416893d5 100644
--- a/src/dotnet/Interop.cs
+++ b/src/dotnet/Interop.cs
@@ -94,14 +94,27 @@ namespace Fsp.Interop
     }
 
     [StructLayout(LayoutKind.Sequential)]
-    internal struct VolumeInfo
+    public struct VolumeInfo
     {
         internal const int VolumeLabelSize = 32;
 
-        internal UInt64 TotalSize;
-        internal UInt64 FreeSize;
+        public UInt64 TotalSize;
+        public UInt64 FreeSize;
         internal UInt16 VolumeLabelLength;
         internal unsafe fixed UInt16 VolumeLabel[VolumeLabelSize];
+
+        internal unsafe void SetVolumeLabel(String Value)
+        {
+            fixed (UInt16 *P = VolumeLabel)
+            {
+                int Size = Value.Length;
+                if (Size > VolumeLabelSize)
+                    Size = VolumeLabelSize;
+                for (int I = 0; Size > I; I++)
+                    P[I] = Value[I];
+                VolumeLabelLength = VolumeLabelSize;
+            }
+        }
     }
 
     [StructLayout(LayoutKind.Sequential)]
@@ -161,9 +174,9 @@ namespace Fsp.Interop
             internal delegate Int32 GetSecurityByName(
                 IntPtr FileSystem,
                 [MarshalAs(UnmanagedType.LPWStr)] String FileName,
-                out UInt32 PFileAttributes/* or ReparsePointIndex */,
+                IntPtr PFileAttributes/* or ReparsePointIndex */,
                 IntPtr SecurityDescriptor,
-                out UIntPtr PSecurityDescriptorSize);
+                IntPtr PSecurityDescriptorSize);
             [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
             internal delegate Int32 Create(
                 IntPtr FileSystem,
@@ -264,7 +277,7 @@ namespace Fsp.Interop
                 IntPtr FileSystem,
                 IntPtr FileContext,
                 IntPtr SecurityDescriptor,
-                out UIntPtr PSecurityDescriptorSize);
+                IntPtr PSecurityDescriptorSize);
             [UnmanagedFunctionPointer(CallingConvention.Cdecl)]
             internal delegate Int32 SetSecurity(
                 IntPtr FileSystem,