NFSv2/v3: Fix a memory leak when using -onolock

mainline: 5cef338b

    Neil Brown said:
    > Hi Trond,
    >
    > We found that a machine which made moderately heavy use of
    > 'automount' was leaking some nfs data structures - particularly the
    > 4K allocated by rpc_alloc_iostats.
    > It turns out that this only happens with filesystems with -onolock
    > set.

    > The problem is that if NFS_MOUNT_NONLM is set, nfs_start_lockd doesn't
    > set server->destroy, so when the filesystem is unmounted, the
    > ->client_acl is not shutdown, and so several resources are still
    > held.  Multiple mount/umount cycles will slowly eat away memory
    > several pages at a time.

    Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

Acked-by: Neil Brown <neilb@suse.de>
Signed-off-by: Neil Brown <neilb@suse.de>
CC: Oliver Pinter <oliver.pntr@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>