Add description for "file-system EXT2FS" and "options EXT2FS_SYSTEM_FLAGS".

share/man/man4/options.4

@@ -1,4 +1,4 @@
-.\"	$NetBSD: options.4,v 1.17 1997/04/21 13:00:52 mrg Exp $
+.\"	$NetBSD: options.4,v 1.18 1997/06/12 09:09:11 bouyer Exp $
 .\"
 .\" Copyright (c) 1996
 .\" 	Perry E. Metzger.  All rights reserved.
@@ -229,6 +229,17 @@ for details.
 Includes code implementing the Berkeley Fast File System
 .Em ( FFS ) .
 Most machines need this if they are not running diskless.
+.It Cd file-system EXT2FS
+Includes code implementing the Second Extended File System
+.Em ( EXT2FS ) .
+This is the most commonly used file system on the Linux operating system,
+and is provided here for compatibility. Some of the specific features
+of
+.Em EXT2FS 
+like the "behavior on errors" are not implemented. This file system can't be
+used with UID or GID greather than 65535. See
+.Xr mount_ext2fs 8
+for details.
 .It Cd file-system LFS
 Include the log structured file system
 .Em ( LFS ) .
@@ -399,6 +410,14 @@ is to examine your system's current computed value with
 until either the namei cache hit rate improves or it is determined that
 your system does not benefit substantially from an increase in the size of
 the namei cache.
+.It Cd options EXT2FS_SYSTEM_FLAGS
+This option changes the behavior of the APPEND and IMMUTABLE flags
+for a file on an
+.Em EXT2FS 
+filesystem. Without this option, the superuser or owner of the file can
+set and clear them. With this option, only the superuser can set them, and
+they can't be cleared if the securelevel is greather than 0. See also
+.Xr chflags 1 .
 .El
 .Ss Miscellaneous Options
 .Bl -ohang