2.2 Status Codes
The reply message lists the common error codes that are directly generated by the function. Error codes can also be generated by code below the file system (such as RAID drivers or disk drivers) or above the file system (such as virus scanners).
A server SHOULD return a status of STATUS_INVALID_DEVICE_REQUEST when a message is not supported remotely or is not supported on the file system on which the file or directory handle specified exists.<14><15>
STATUS_BUFFER_OVERFLOW is a warning code and not an error code. This warning means that the given output buffer is not large enough to contain all of the requested information. Unless otherwise noted, a given operation SHOULD attempt to return as much data as it reasonably can.