Check validity of cl_rpcclient in nfs_server_list_show

As soon as the nfs_client gets created, its cl_rpcclient is set to
ERR_PTR(-EINVAL). The rpc client structure is allocated later. Check
if the client is ready before using the cl_rpcclient pointer.
Signed-off-by: Malahal Naineni <malahal@us.ibm.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/client.c

@@ -1868,6 +1868,10 @@ static int nfs_server_list_show(struct seq_file *m, void *v)
 	/* display one transport per line on subsequent lines */
 	clp = list_entry(v, struct nfs_client, cl_share_link);
 
+	/* Check if the client is initialized */
+	if (clp->cl_cons_state != NFS_CS_READY)
+		return 0;
+
 	seq_printf(m, "v%u %s %s %3d %s\n",
 		   clp->rpc_ops->version,
 		   rpc_peeraddr2str(clp->cl_rpcclient, RPC_DISPLAY_HEX_ADDR),