FltIsVolumeWritable failure

NTFSD
1

I have a mini-filter that has run without problem on many PCs. Now I have a
problem where the C: volume (instance) on a particular PC is always failing
the FltIsVolumeWritable call with a result of STATUS_INVALID_DEVICE_REQUEST.

The volume is a NTFS fixed disk volume that is the boot/system volume. It
physically consists of two SATA drives striped with the NVIDIA NVRAID built
into the motherboard chips. The NVRAID appears as a simple single drive to
XP.

It is running 32-bit XP SP2 with the latest updates. It is a dual opteron
X8N-DL ASUS motherboard.

Can anyone give me any hints on chasing this problem down?

2

I should have included the code:

NTSTATUS CpsInstanceSetup (
IN PCFLT_RELATED_OBJECTS FltObjects,
IN FLT_INSTANCE_SETUP_FLAGS Flags,
IN DEVICE_TYPE VolumeDeviceType,
IN FLT_FILESYSTEM_TYPE VolumeFilesystemType
) {
NTSTATUS status;
BOOLEAN isWritable;

PAGED_CODE();

if ( VolumeDeviceType != FILE_DEVICE_DISK_FILE_SYSTEM )
return STATUS_FLT_DO_NOT_ATTACH;

status = FltIsVolumeWritable( FltObjects->Volume, &isWritable );