NFSv4: Add tracepoints for debugging rename

Add tracepoints to debug renames.
Signed-off-by: NTrond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfs4proc.c

@@ -3329,7 +3329,8 @@ static void nfs4_proc_rename_rpc_prepare(struct rpc_task *task, struct nfs_renam
 static int nfs4_proc_rename_done(struct rpc_task *task, struct inode *old_dir,
 				 struct inode *new_dir)
 {
-	struct nfs_renameres *res = task->tk_msg.rpc_resp;
+	struct nfs_renamedata *data = task->tk_calldata;
+	struct nfs_renameres *res = &data->res;
 
 	if (!nfs4_sequence_done(task, &res->seq_res))
 		return 0;
@@ -3375,9 +3376,10 @@ static int nfs4_proc_rename(struct inode *old_dir, struct qstr *old_name,
 	struct nfs4_exception exception = { };
 	int err;
 	do {
-		err = nfs4_handle_exception(NFS_SERVER(old_dir),
-				_nfs4_proc_rename(old_dir, old_name,
-					new_dir, new_name),
+		err = _nfs4_proc_rename(old_dir, old_name,
+					new_dir, new_name);
+		trace_nfs4_rename(old_dir, old_name, new_dir, new_name, err);
+		err = nfs4_handle_exception(NFS_SERVER(old_dir), err,
 				&exception);
 	} while (exception.retry);
 	return err;

fs/nfs/nfs4trace.h

@@ -461,6 +461,49 @@ DEFINE_NFS4_LOOKUP_EVENT(nfs4_remove);
 DEFINE_NFS4_LOOKUP_EVENT(nfs4_get_fs_locations);
 DEFINE_NFS4_LOOKUP_EVENT(nfs4_secinfo);
 
+TRACE_EVENT(nfs4_rename,
+		TP_PROTO(
+			const struct inode *olddir,
+			const struct qstr *oldname,
+			const struct inode *newdir,
+			const struct qstr *newname,
+			int error
+		),
+
+		TP_ARGS(olddir, oldname, newdir, newname, error),
+
+		TP_STRUCT__entry(
+			__field(dev_t, dev)
+			__field(int, error)
+			__field(u64, olddir)
+			__string(oldname, oldname->name)
+			__field(u64, newdir)
+			__string(newname, newname->name)
+		),
+
+		TP_fast_assign(
+			__entry->dev = olddir->i_sb->s_dev;
+			__entry->olddir = NFS_FILEID(olddir);
+			__entry->newdir = NFS_FILEID(newdir);
+			__entry->error = error;
+			__assign_str(oldname, oldname->name);
+			__assign_str(newname, newname->name);
+		),
+
+		TP_printk(
+			"error=%d (%s) oldname=%02x:%02x:%llu/%s "
+			"newname=%02x:%02x:%llu/%s",
+			__entry->error,
+			show_nfsv4_errors(__entry->error),
+			MAJOR(__entry->dev), MINOR(__entry->dev),
+			(unsigned long long)__entry->olddir,
+			__get_str(oldname),
+			MAJOR(__entry->dev), MINOR(__entry->dev),
+			(unsigned long long)__entry->newdir,
+			__get_str(newname)
+		)
+);
+
 DECLARE_EVENT_CLASS(nfs4_inode_event,
 		TP_PROTO(
 			const struct inode *inode,