NFS: include filelayout DS rpc stats in mountstats

Include RPC statistics from all data servers in /proc/self/mountstats for pNFS
filelayout mounts.

Signed-off-by: Weston Andros Adamson <dros@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index 22dfc24..dc0c3cc 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -103,6 +103,7 @@
 struct rpc_call_ops {
 	void (*rpc_call_prepare)(struct rpc_task *, void *);
 	void (*rpc_call_done)(struct rpc_task *, void *);
+	void (*rpc_count_stats)(struct rpc_task *, void *);
 	void (*rpc_release)(void *);
 };