linux-imx

NFS: Store the credential of the mount process in the nfs_server

Store the credential of the mount process so that we can determine
information such as the user namespace.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>