Comment 1 for bug 199388

Please see the Alpha 6 release notes, in which I took care to document this bug:

  * XFS cannot be selected in the alternate and server installer's partitioner; this will be fixed in the next build. If you need this, run chmod +x /lib/partman/finish.d/70aptinstall_xfs /lib/partman/valid_filesystems/25xfs from a root shell beforehand. The desktop installer is not affected.

partman-xfs (35ubuntu2) hardy; urgency=low

  * Make finish.d/aptinstall_xfs and valid_filesystems/xfs executable again.

 -- Colin Watson <email address hidden> Thu, 06 Mar 2008 12:04:28 +0000

This was due to an ancient svn->bzr import bug, which I fixed long ago but unfortunately its effects persist and still occasionally come back to bite us.