NFS: Add tracepoints for debugging generic file create events

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 2263a6b..9c07812 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -1612,7 +1612,9 @@
 	attr.ia_mode = mode;
 	attr.ia_valid = ATTR_MODE;
 
+	trace_nfs_create_enter(dir, dentry, open_flags);
 	error = NFS_PROTO(dir)->create(dir, dentry, &attr, open_flags);
+	trace_nfs_create_exit(dir, dentry, open_flags, error);
 	if (error != 0)
 		goto out_err;
 	return 0;