svn commit: r284531 - head/sbin/umount

[Rick Macklem]

Author: rmacklem
Date: Wed Jun 17 23:24:46 2015
New Revision: 284531
URL: https://svnweb.freebsd.org/changeset/base/284531

Log:
  Document that a forced dismount of an NFSv3 mount when the
  NLM (rpc.lockd) is running can crash the system.
  Unfortunately this is not easy to fix, but I have left
  PR#200585 open.
  
  PR:		200585
  MFC after:	3 days

Modified:
  head/sbin/umount/umount.8

Modified: head/sbin/umount/umount.8
==============================================================================
--- head/sbin/umount/umount.8	Wed Jun 17 22:52:12 2015	(r284530)
+++ head/sbin/umount/umount.8	Wed Jun 17 23:24:46 2015	(r284531)
@@ -28,7 +28,7 @@
 .\"     @(#)umount.8	8.2 (Berkeley) 5/8/95
 .\" $FreeBSD$
 .\"
-.Dd November 22, 2014
+.Dd June 17, 2015
 .Dt UMOUNT 8
 .Os
 .Sh NAME
@@ -81,6 +81,9 @@ The root file system cannot be forcibly 
 For NFS, a forced dismount can take up to 1 minute or more to
 complete against an unresponsive server and may throw away
 data not yet written to the server for this case.
+Also, doing a forced dismount of an NFSv3 mount when
+.Xr rpc.lockd 8
+is running is unsafe and can result in a crash.
 .It Fl h Ar host
 Only file systems mounted from the specified host will be
 unmounted.