From 949a19d4024bc421eeb78e8b05c9482a2e6ff788 Mon Sep 17 00:00:00 2001
From: rmacklem <rmacklem@FreeBSD.org>
Date: Wed, 1 May 2013 22:50:45 +0000
Subject: Document the fact that an NFSv4 mount against a volume on the same
 host can result in a hung NFS server and is not recommended. This is a
 content change.

MFC after:	2 weeks
---
 usr.sbin/nfsd/nfsv4.4 | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/usr.sbin/nfsd/nfsv4.4 b/usr.sbin/nfsd/nfsv4.4
index 679bb69..e0e6023 100644
--- a/usr.sbin/nfsd/nfsv4.4
+++ b/usr.sbin/nfsd/nfsv4.4
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd December 23, 2012
+.Dd May 1, 2013
 .Dt NFSV4 4
 .Os
 .Sh NAME
@@ -287,6 +287,13 @@ and
 daemons at boot time via the ``nfsuserd_flags'' and ``nfscbd_flags''
 .Xr rc.conf 5
 variables.
+.Pp
+NFSv4 mount(s) against exported volume(s) on the same host are not recommended,
+since this can result in a hung NFS server.
+It occurs when an nfsd thread tries to do an NFSv4 VOP_RECLAIM()/Close RPC
+as part of acquiring a new vnode.
+If all other nfsd threads are blocked waiting for lock(s) held by this nfsd
+thread, then there isn't an nfsd thread to service the Close RPC.
 .Sh FILES
 .Bl -tag -width /var/db/nfs-stablerestart.bak -compact
 .It Pa /var/db/nfs-stablerestart
-- 
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