kern/95222: File sections on ISO9660 level 3 CDs ignored

[Pete]

>Number:         95222
>Category:       kern
>Synopsis:       File sections on ISO9660 level 3 CDs ignored
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Apr 02 11:50:17 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Pete
>Release:        6.0
>Organization:
>Environment:
N/A
>Description:
The current cd9660 implementation does not support "file sections" (a feature allowing
portions of a file to be reused), even though this is required for Level 3 compliant 
implementations.

Windows users sometimes creates such CDs, but since they are rather uncommon, 
I believe it only happens if they tweak their burner settings. Windows has supported
Level 3, "Joliet level 3", for a decade or so.
>How-To-Repeat:
1, Burn a known file in multiple sections (Roxio's software for Windows appears to 
be able to do this)
2, Mount CD in FreeBSD
3, Copy the known file, and notice that although it appears to succeed, only
a portion of the file is copied. (Also, file sizes in listings are wrong.)
>Fix:
Ideally:
Properly implement file sections. AFAICT, none of the BSDs have it implemented, but
it's supported by Linux, see for example:
http://www.linux-m32r.org/lxr/http/source/fs/isofs/inode.c

This requires significant work, and some potential problems in implementing this
for NetBSD were discussed at:
http://groups.google.com/group/fa.netbsd.current-users/
browse_frm/thread/c917600103080381

In the meantime, it shouldn't be too difficult to add warnings when attempting to read
a multi-section file. One could also warn at mount time -- the only difference between
level 2 and level 3 is that the latter allows for multi-section files -- but the drawback of
this is that level 3 doesn't require multi-sections, so a warning might unnecessarily
scare the user.

Please note that mounting the CD without Joliet extensions doesn't make the files
readable.
>Release-Note:
>Audit-Trail:
>Unformatted: