diff --git a/src/dll/fsctl.c b/src/dll/fsctl.c
index 036d29e3..4dffb187 100644
--- a/src/dll/fsctl.c
+++ b/src/dll/fsctl.c
@@ -33,22 +33,20 @@ FSP_API NTSTATUS FspFsctlCreateVolume(PWSTR DevicePath,
     GlobalDevicePath(DevicePathBuf, sizeof DevicePathBuf, DevicePath);
 
     SecurityDescriptorSize = 0;
-    if (!MakeSelfRelativeSD(SecurityDescriptor, 0, &SecurityDescriptorSize))
+    MakeSelfRelativeSD(SecurityDescriptor, 0, &SecurityDescriptorSize);
+    ParamsBuf = malloc(sizeof *ParamsBuf + SecurityDescriptorSize);
+    if (0 == ParamsBuf)
     {
-        ParamsBuf = malloc(sizeof *ParamsBuf + SecurityDescriptorSize);
-        if (0 == ParamsBuf)
-        {
-            Result = STATUS_INSUFFICIENT_RESOURCES;
-            goto exit;
-        }
-        SecurityDescriptorBuf = (PVOID)(ParamsBuf + 1);
-        if (!MakeSelfRelativeSD(SecurityDescriptor, SecurityDescriptorBuf, &SecurityDescriptorSize))
-        {
-            Result = FspNtStatusFromWin32(GetLastError());
-            goto exit;
-        }
-        *ParamsBuf = *Params;
+        Result = STATUS_INSUFFICIENT_RESOURCES;
+        goto exit;
     }
+    SecurityDescriptorBuf = (PVOID)(ParamsBuf + 1);
+    if (!MakeSelfRelativeSD(SecurityDescriptor, SecurityDescriptorBuf, &SecurityDescriptorSize))
+    {
+        Result = FspNtStatusFromWin32(GetLastError());
+        goto exit;
+    }
+    *ParamsBuf = *Params;
 
     DeviceHandle = CreateFileW(DevicePathBuf,
         0, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, 0, OPEN_EXISTING, 0, 0);
diff --git a/src/sys/driver.h b/src/sys/driver.h
index 28e35b4e..469703e6 100644
--- a/src/sys/driver.h
+++ b/src/sys/driver.h
@@ -295,7 +295,7 @@ NTSTATUS FspCreateDeviceObjectList(
     PDRIVER_OBJECT DriverObject, PDEVICE_OBJECT **PDeviceObjects, PULONG PDeviceObjectCount);
 VOID FspDeleteDeviceObjectList(
     PDEVICE_OBJECT *DeviceObjects, ULONG DeviceObjectCount);
-NTSTATUS FspHasDeviceObject(
+NTSTATUS FspLookupDeviceObject(
     PDRIVER_OBJECT DriverObject, PDEVICE_OBJECT DeviceObject);
 
 /* debug */
diff --git a/src/sys/fsctl.c b/src/sys/fsctl.c
index 11696f40..ea4adbcd 100644
--- a/src/sys/fsctl.c
+++ b/src/sys/fsctl.c
@@ -108,10 +108,10 @@ static NTSTATUS FspFsctlMountVolume(
     PAGED_CODE();
 
     NTSTATUS Result;
-    PDEVICE_OBJECT RealDevice = IrpSp->Parameters.MountVolume.DeviceObject;
+    PDEVICE_OBJECT RealDevice = IrpSp->Parameters.MountVolume.Vpb->RealDevice;
 
     /* check the passed in volume object; it must be one of our own */
-    Result = FspHasDeviceObject(DeviceObject->DriverObject, RealDevice);
+    Result = FspLookupDeviceObject(DeviceObject->DriverObject, RealDevice);
     if (!NT_SUCCESS(Result))
     {
         if (STATUS_NO_SUCH_DEVICE == Result)
diff --git a/src/sys/misc.c b/src/sys/misc.c
index 16e9ed38..d025f742 100644
--- a/src/sys/misc.c
+++ b/src/sys/misc.c
@@ -83,7 +83,7 @@ VOID FspDeleteDeviceObjectList(
     ExFreePoolWithTag(DeviceObjects, FSP_TAG);
 }
 
-NTSTATUS FspHasDeviceObject(
+NTSTATUS FspLookupDeviceObject(
     PDRIVER_OBJECT DriverObject, PDEVICE_OBJECT DeviceObject)
 {
     NTSTATUS Result = STATUS_NO_SUCH_DEVICE;