From 861abdadf9db4dd7ba577537ba262fcda29869dd Mon Sep 17 00:00:00 2001
From: Dmitry Chagin <dchagin@FreeBSD.org>
Date: Tue, 13 Jun 2023 15:22:09 +0300
Subject: [PATCH] namei: Add a comment explaining ISRESTARTED flag

Reviewed by:		kib
Differential Revision:	https://reviews.freebsd.org/D40494
---
 sys/kern/vfs_lookup.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/sys/kern/vfs_lookup.c b/sys/kern/vfs_lookup.c
index c813296b493..20919fb38b4 100644
--- a/sys/kern/vfs_lookup.c
+++ b/sys/kern/vfs_lookup.c
@@ -81,6 +81,11 @@ static void NDVALIDATE_impl(struct nameidata *, int);
 #define NDVALIDATE(ndp)
 #endif
 
+/*
+ * Prepare namei() to restart. Reset components to its original state and set
+ * ISRESTARTED flag which signals the underlying lookup code to change the root
+ * from ABI root to actual root and prevents a further restarts.
+ */
 #define	NDRESTART(ndp) do {						\
 	NDREINIT_DBG(ndp);						\
 	ndp->ni_resflags = 0;						\