Mention potential reasons for EPERM.

Requested by Anon Ymous.

sbin/mount/mount.8

@@ -1,4 +1,4 @@
-.\"	$NetBSD: mount.8,v 1.56 2006/10/31 08:12:46 mjf Exp $
+.\"	$NetBSD: mount.8,v 1.57 2007/01/06 14:43:27 elad Exp $
 .\"
 .\" Copyright (c) 1980, 1989, 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -29,7 +29,7 @@
 .\"
 .\"     @(#)mount.8	8.8 (Berkeley) 6/16/94
 .\"
-.Dd September 25, 2006
+.Dd January 6, 2007
 .Dt MOUNT 8
 .Os
 .Sh NAME
@@ -420,6 +420,19 @@ indicates that the mount for the specified file-system type cannot be
 completed because the kernel lacks support for the said file-system.
 See
 .Xr options 4 .
+.Pp
+The error
+.Dq Operation not permitted
+may indicate that the mount options include privileged options and/or
+don't include options that exclude privileged options.
+One should try using at least
+.Dq nodev
+and
+.Dq nosuid
+in such cases:
+.Bd -literal -offset indent
+mount -t cd9660 -o nodev,nosuid /dev/cd0a /mnt
+.Ed
 .Sh SEE ALSO
 .Xr df 1 ,
 .Xr mount 2 ,