Index: class2.c
===================================================================
--- drivers/storage/class/class2.c	(revision 70282)
+++ drivers/storage/class/class2.c	(working copy)
@@ -137,6 +137,7 @@
 /* The following hack to assign drive letters with a non-PnP storage stack */
 
 typedef struct _CLASS_DEVICE_INFO {
+  ULONG Signature;
   ULONG DeviceType;
   ULONG Partitions;
   ULONG DeviceNumber;
@@ -346,19 +347,29 @@
     IN PDEVICE_OBJECT DeviceObject,
     IN PIRP Irp)
 {
+    PCLASS_DEVICE_INFO DeviceInfo = DeviceObject->DeviceExtension;
+    PDEVICE_EXTENSION DeviceExtension = DeviceObject->DeviceExtension;
     PIO_STACK_LOCATION IrpSp = IoGetCurrentIrpStackLocation(Irp);
+    NTSTATUS Status;
 
     if (IrpSp->MinorFunction == IRP_MN_START_DEVICE)
     {
-        IoSkipCurrentIrpStackLocation(Irp);
-        return STATUS_SUCCESS;
+        ASSERT(DeviceInfo->Signature == '2slc');
+        if (!IoForwardIrpSynchronously(DeviceInfo->LowerDevice, Irp))
+        {
+            Irp->IoStatus.Status = STATUS_UNSUCCESSFUL;
+        }
+        Status = Irp->IoStatus.Status;
+        IoCompleteRequest(Irp, IO_NO_INCREMENT);
+        return Status;
     }
     else if (IrpSp->MinorFunction == IRP_MN_REMOVE_DEVICE)
     {
-        PCLASS_DEVICE_INFO DeviceInfo = DeviceObject->DeviceExtension;
-
+        ASSERT(DeviceInfo->Signature == '2slc');
         ScsiClassRemoveDriveLetter(DeviceInfo);
 
+        IoForwardIrpSynchronously(DeviceInfo->LowerDevice, Irp);
+
         Irp->IoStatus.Status = STATUS_SUCCESS;
         IoCompleteRequest(Irp, IO_NO_INCREMENT);
 
@@ -368,9 +379,11 @@
     }
     else
     {
-        Irp->IoStatus.Status = STATUS_NOT_SUPPORTED;
-        IoCompleteRequest(Irp, IO_NO_INCREMENT);
-        return STATUS_NOT_SUPPORTED;
+        IoSkipCurrentIrpStackLocation(Irp);
+        if (DeviceInfo->Signature == '2slc')
+            return IoCallDriver(DeviceInfo->LowerDevice, Irp);
+        else
+            return IoCallDriver(DeviceExtension->PortDeviceObject, Irp);
     }
 }
 
@@ -403,6 +416,7 @@
 
         DeviceInfo = DeviceObject->DeviceExtension;
         RtlZeroMemory(DeviceInfo, sizeof(CLASS_DEVICE_INFO));
+        DeviceInfo->Signature = '2slc';
 
         /* Attach it to the PDO */
         DeviceInfo->LowerDevice = IoAttachDeviceToDeviceStack(DeviceObject, PhysicalDeviceObject);
@@ -628,7 +642,7 @@
     // Invoke the device-specific routine, if one exists. Otherwise complete
     // with SUCCESS
     //
-
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     if (deviceExtension->ClassCreateClose) {
 
         return deviceExtension->ClassCreateClose(DeviceObject, Irp);
@@ -678,6 +692,7 @@
     ULONG               maximumTransferLength = deviceExtension->PortCapabilities->MaximumTransferLength;
     NTSTATUS            status;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     if (DeviceObject->Flags & DO_VERIFY_VOLUME &&
         !(currentIrpStack->Flags & SL_OVERRIDE_VERIFY_VOLUME)) {
 
@@ -1041,6 +1056,7 @@
     SCSI_REQUEST_BLOCK  srb;
     NTSTATUS            status;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     //
     // Allocate read capacity buffer from nonpaged pool.
     //
@@ -1264,6 +1280,7 @@
     PSCSI_REQUEST_BLOCK srb;
     KIRQL currentIrql;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     //
     // Allocate context from nonpaged pool.
     //
@@ -1409,6 +1426,7 @@
     PCOMPLETION_CONTEXT context;
     PCDB cdb;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     //
     // Allocate Srb from nonpaged pool.
     //
@@ -1630,6 +1648,7 @@
     ULONG              i;
     PSCSI_REQUEST_BLOCK srb;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     DebugPrint((2, "ScsiClassSplitRequest: Requires %d IRPs\n", irpCount));
     DebugPrint((2, "ScsiClassSplitRequest: Original IRP %lx\n", Irp));
 
@@ -1817,6 +1836,7 @@
     NTSTATUS status;
     BOOLEAN retry;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     //
     // Check SRB status for success of completing request.
     //
@@ -1969,6 +1989,7 @@
     NTSTATUS            status;
     BOOLEAN             retry;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     //
     // Check SRB status for success of completing request.
     //
@@ -2190,6 +2211,7 @@
 
     PAGED_CODE();
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     dummy.QuadPart = 0;
 
     //
@@ -2481,6 +2503,7 @@
     ULONG             i;
 #endif
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
 
     //
     // Check that request sense buffer is valid.
@@ -3161,6 +3184,7 @@
     PIO_STACK_LOCATION nextIrpStack = IoGetNextIrpStackLocation(Irp);
     ULONG transferByteCount;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     //
     // Determine the transfer count of the request.  If this is a read or a
     // write then the transfer count is in the Irp stack.  Otherwise assume
@@ -3292,6 +3316,7 @@
     ULONG               logicalBlockAddress;
     USHORT              transferBlocks;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     //
     // Calculate relative sector address.
     //
@@ -3511,6 +3536,7 @@
     ULONG retries = 1;
     NTSTATUS status;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     RtlZeroMemory(&srb, sizeof(SCSI_REQUEST_BLOCK));
 
     //
@@ -3687,6 +3713,7 @@
 
     PAGED_CODE();
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     //
     // Write length to SRB.
     //
@@ -3860,6 +3887,7 @@
 
     PDEVICE_EXTENSION deviceExtension = DeviceObject->DeviceExtension;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
 
     //
     // Call the class specific driver DeviceControl routine.
@@ -3909,6 +3937,7 @@
     NTSTATUS status;
     ULONG modifiedIoControlCode;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     if (irpStack->Parameters.DeviceIoControl.IoControlCode ==
         IOCTL_STORAGE_RESET_DEVICE) {
 
@@ -4456,6 +4485,7 @@
 {
     PDEVICE_EXTENSION deviceExtension = DeviceObject->DeviceExtension;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     if (deviceExtension->ClassShutdownFlush) {
 
         //
@@ -4609,6 +4639,7 @@
 
         PDEVICE_EXTENSION deviceExtension = deviceObject->DeviceExtension;
 
+        ASSERT(*(PULONG)deviceExtension != '2slc');
         //
         // Fill in entry points
         //
@@ -4781,7 +4812,7 @@
 
     if (Release) {
 
-        ObDereferenceObject(PortDeviceObject);
+        //ObDereferenceObject(PortDeviceObject);
         return STATUS_SUCCESS;
     }
 
@@ -4805,6 +4836,7 @@
 
         return status;
     }
+    ObDereferenceObject(srb.DataBuffer);
 
     //
     // Return the new port device object pointer.
@@ -4854,6 +4886,7 @@
     PDEVICE_EXTENSION deviceExtension = DeviceObject->DeviceExtension;
     PSCSI_REQUEST_BLOCK srb;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
     //
     // Get a pointer to the SRB.
     //
@@ -5108,6 +5141,8 @@
                         deviceExtension->PhysicalDevice->DeviceExtension;
     PIRP originalIrp;
 
+    ASSERT(*(PULONG)deviceExtension != '2slc');
+    ASSERT(*(PULONG)physicalExtension != '2slc');
     originalIrp = irpStack->Parameters.Others.Argument1;
 
     //