HP CIFS File Locking Interoperation

benefit is improved security, but in most cases the additional checks will be redundant to the

application checks, and the cost will be reduced performance due to the extra overhead of

checking for locks on every read and write.

CIFS/9000 enables strict locking on a per-share basis in the smb.conf file:

[share_name]

strict locking = yes

The default is “no”.

Blocking locks enables the smbd to recognize a timeout period specified on a LockFileEx call.

If a previous lock is encountered by a client attempting a byte range lock, the smbd will wait

(block) for the timeout period to expire before failing the lock. If the previous lock is released

before the timeout, the smbd will then grant the pending lock. When disabled, the lock

request is failed immediately.

CIFS/9000 disables blocking locks on a per -share basis in the smb.conf file:

[share_name]

blocking locks = no

The default is “yes”.

5.3. OPPORTUNISTIC LOCKING (Oplocks) is implemented by the

CIFS/9000 server on a per-share basis in the smb.conf file. CIFS/9000 Oplock functionality

operates just like Windows. Oplocks are enabled by default for each share, which allows the

Windows client to cache a local copy of a file for:

Read-ahead

Write-caching

Lock caching

CIFS/9000 disables Oplocks on a per -share basis in the smb.conf file:

[share_name]

oplocks = no

The default is “yes”. The default oplock type is Level1.

CIFS/9000 enables Level2 Oplocks on a per -share basis in the smb.conf file:

[share_name]

level2 oplocks = yes

The default is “no”. Oplocks must also be set to “yes” for the Level2 oplock parameter to

function.

Oplocks apply to Windows clients only. File sharing issues arise when concurrent file access

occurs between Windows clients and UNIX clients, PC-NFS clients, or on files that have been

NFS-mounted. A key issue with sharing files between UNIX/NFS, PC-NFS, and

Windows clients is that a Windows client can request an Oplock from the

CIFS/9000 server and be granted the Oplock (thus caching the file locally), but a