HP UX Common Internet File System (CIFS) Client/Server Software manual

6.2WINDOWS ONLY CLIENT ACCESS – NFS Mounted File System

Clients

Windows UNIX PC-NFS CIFS/9000 Windows

CIFS/9000	NFS
File

The diagram above shows 2 Windows clients requesting concurrent file access on the CIFS/9000 server to a NFS mounted file system. The key issue for this configuration is that because all Windows client access occurs via the CIFS/9000 server smbd processes, the file access is coordinated by CIFS/9000 even thought the disk file is remote, thus providing full file locking functionality in a Windows homogenous environment.

Mandatory Share Mode locking is fully implemented. Although no actual lock is placed upon the disk file over the NFS mount, the client processes believe that there is, and the server smbd processes coordinate to respect each other’s pseudo-lock. This locking scenario only applies when a single CIFS/9000 server is supplying both client connection requests.

Byte Range locking is fully implemented. The CIFS/9000 smbd process actually calls the UNIX fcntl to explicitly lock the byte range in UNIX with advisory byte range locks. The UNIX byte range is then propagated to NFS, so byte range locking is interoperable with NFS. With Windows-only concurrent access, the smbd process interprets the UNIX advisory lock as a Windows byte range lock, which the clients honor.

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Opportunistic (Oplocks) locking is fully implemented for the same reason as the Mandatory Share Mode lock, and only applies when a single CIFS/9000 server is supplying both client connection requests.

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