NFS: make cb_ident_idr per net ns

This patch makes ID's infrastructure network namespace aware. This was done
mainly because of nfs_client_lock, which is desired to be per network
namespace, but protects NFS clients ID's.

NOTE: NFS client's net pointer have to be set prior to ID initialization,
proper assignment was moved.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/callback_xdr.c b/fs/nfs/callback_xdr.c
index 2f45aa7..e14af46 100644
--- a/fs/nfs/callback_xdr.c
+++ b/fs/nfs/callback_xdr.c
@@ -876,7 +876,7 @@
 		return rpc_garbage_args;
 
 	if (hdr_arg.minorversion == 0) {
-		cps.clp = nfs4_find_client_ident(hdr_arg.cb_ident);
+		cps.clp = nfs4_find_client_ident(rqstp->rq_xprt->xpt_net, hdr_arg.cb_ident);
 		if (!cps.clp || !check_gss_callback_principal(cps.clp, rqstp))
 			return rpc_drop_reply;
 	}