NFSv4: Add tracepoints for debugging the idmapper

Add tracepoints to help debug uid/gid mappings to username/group.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/idmap.c b/fs/nfs/idmap.c
index 65c7d91..e9b0c59 100644
--- a/fs/nfs/idmap.c
+++ b/fs/nfs/idmap.c
@@ -49,6 +49,7 @@
 
 #include "internal.h"
 #include "netns.h"
+#include "nfs4trace.h"
 
 #define NFS_UINT_MAXLEN 11
 
@@ -849,6 +850,7 @@
 		if (!uid_valid(*uid))
 			ret = -ERANGE;
 	}
+	trace_nfs4_map_name_to_uid(name, namelen, id, ret);
 	return ret;
 }
 
@@ -865,6 +867,7 @@
 		if (!gid_valid(*gid))
 			ret = -ERANGE;
 	}
+	trace_nfs4_map_group_to_gid(name, namelen, id, ret);
 	return ret;
 }
 
@@ -879,6 +882,7 @@
 		ret = nfs_idmap_lookup_name(id, "user", buf, buflen, idmap);
 	if (ret < 0)
 		ret = nfs_map_numeric_to_string(id, buf, buflen);
+	trace_nfs4_map_uid_to_name(buf, ret, id, ret);
 	return ret;
 }
 int nfs_map_gid_to_group(const struct nfs_server *server, kgid_t gid, char *buf, size_t buflen)
@@ -892,5 +896,6 @@
 		ret = nfs_idmap_lookup_name(id, "group", buf, buflen, idmap);
 	if (ret < 0)
 		ret = nfs_map_numeric_to_string(id, buf, buflen);
+	trace_nfs4_map_gid_to_group(buf, ret, id, ret);
 	return ret;
 }