NFSv4 deny-write open lock

You can specify whether a deny-write open lock blocks writes, which is expected and required by NFSv4, Samba, and Windows.

For more information, see Managing GPFS access control lists.
nfs4
Must be specified for file systems that support NFS V4 and file systems that are mounted on Windows. NFS4 is the default.
posix
Specified for file systems that support NFS V3 or file systems that are not NFS exported.

Allows NFS writes even in the presence of a deny-write open lock.