docs/129792: mount_msdosfs(8) man page is missing the -o large option

[Chris]

>Number:         129792
>Category:       docs
>Synopsis:       mount_msdosfs(8) man page is missing the -o large option
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-doc
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          doc-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Dec 20 17:50:03 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:     Chris
>Release:        7.1-PRERELEASE
>Organization:
>Environment:
FreeBSD eco 7.1-PRERELEASE FreeBSD 7.1-PRERELEASE #1: Tue Dec 16 18:28:48 GMT 2008     root at eco:/usr/obj/usr/src/sys/GENERIC  i386
>Description:
/usr/src/sys/fs/msdosfs/msdosfs_vfsops.c lists 'large' as an option to mount_msdosfs but it is not described in the mount_msdosfs(8) man page. 

>How-To-Repeat:
man 8 mount_msdosfs
>Fix:
Suggested change:

--- mount_msdosfs.8.orig        2005-09-14 17:36:19.000000000 +0100
+++ mount_msdosfs.8     2008-12-20 17:40:11.000000000 +0000
@@ -79,6 +79,8 @@
 Force only the old MS-DOS 8.3 style filenames to be visible.
 .It Cm nowin95
 Completely ignore Windows 95 extended file information.
+.It Cm large
+Mount a file system larger than 128 GB. See CAVEATS section.
 .El
 .It Fl u Ar uid
 Set the owner of the files in the file system to
@@ -208,6 +210,18 @@
 Cluster sizes larger than 16K are unavoidable for file system sizes
 larger than 1G, and also occur when file systems larger than 1G are
 shrunk to smaller than 1G using FIPS.
+.Pp
+The
+.Nm large
+option uses at least 32 bytes of kernel memory (which is not
+reclaimed until the FS is unmounted) for each file on disk to map
+between the 32-bit inode numbers used by VFS and the 64-bit
+pseudo-inode numbers used internally by msdosfs. This is only
+safe to use in certain controlled situations (e.g. read-only FS
+with less than 1 million files).
+Since the mappings do not persist across unmounts (or reboots), these
+filesystems are not suitable for exporting through NFS, or any other
+application that requires fixed inode numbers.
 .Sh HISTORY
 The
 .Nm


>Release-Note:
>Audit-Trail:
>Unformatted: