Pointer to the length of the parameters passed to
or returned from the FSD.
Input
Pointer to the length, in bytes, of the parameters
passed to the file-system driver in pParms.
Output
Pointer to the length, in bytes, of the parameters
returned by the file-system driver in pParms. If this function returns
ERROR_BUFFER_OVERFLOW, pcbParms. points to the size of the buffer
required to hold the parameters returned by the file-system driver. No other
data is returned in this case.