The flush SMB is sent to ensure all data and allocation information for the corresponding file has been written to stable storage. When the fid has a value -1 (hex FFFF) the server performs a flush for all file handles associated with the client and pid. The response is not sent until the writes are complete.
| Client Request ================================== |
Description ================================= |
| UCHAR WordCount; | Count of parameter words = 1 |
| USHORT Fid; | File handle |
| USHORT ByteCount; | Count of data bytes = 0 |
This client request is probably expensive to perform at the server, since the server's operating system is generally scheduling disk writes is a way which is optimal for the system's read and write activity integrated over the entire population of clients. This message from a client "interferes" with the server's ability to optimally schedule the disk activity; clients are discouraged from overuse of this SMB request.
| Server Response ================================== |
Description ================================= |
| UCHAR WordCount; | Count of parameter words = 0 |
| USHORT ByteCount; | Count of data bytes = 0 |
ERRDOS/ERRbadfid
ERRSRV/ERRinvid
ERRSRV/ERRbaduid