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Re: kern/48787


  >  -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.

--                         Wolfgang Solfrank

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