Re: kern/48787

[Wolfgang Solfrank <Wolfgang%Solfrank.net@localhost>]

Hi,

>   >  -rw-r--r--  1 dbus  dbus  4294965248 May  6 15:30 large_file
>   >  -rw-r--r--  1 dbus  dbus  4294965248 May  6 15:30 large_file
>
>   This is a different bug. ISO 9660 level 3 allows to store files
>   larger than 4 GiB - 1. This is done by several directory entries
>   with the same name marking a byte interval ("extent") of the
>   overall file.
...
>   When i assessed the problem in FreeBSD 2 years ago, i noticed
>   a 1:1 relation between iso_node and extent. It would have to
>   become 1:n, or multi-extent files would have to be handled
>   as reason for a well contained error. (Not easy to imagine how
>   the latter shall work consistently.)
>
>   I plan to look for a solution.
>   But that change will be a fat patch, i guess, because it will
>   include an adjustment of the object relationship graph in cd9660.

Be my guest.  However, this will be a larger project than just
updating code in cd9660.  The problem is that an extent (as you
indicate above) ist a "byte interval ... of the overall file".  What this
means is that you can have a file with a first extent of, say, 3 bytes
and a second one of 5 bytes and so on (which looks absurd when
you first look at it, but does make sense if you think about multi-
session cds where you e.g. extend some logfile in a later session.)
The buffer cache in its current implementation doesn't support
this.kind of fragmentation.

Ciao,
Wolfgang
--
Wolfgang%Solfrank.net@localhost                         Wolfgang Solfrank