There is a newly updated ext4 patchset available at:
http://www2.kernel.org/pub/linux/kernel/people/tytso/ext4-patches
and
http://www2.kernel.org/git/?p=linux/kernel/git/tytso/ext4.git
Compared to 2.6.20-ext4-1, I've removed the the i_version patch, since
they had numerous issues, including not building on ia64. I've also
added the nanosecond timestamp patch.
Discussion will be happening on the linux-ext4 mailing list. I plan to
be pushing extent-overlap-bugfix to Linus soon; other patches still need
work before they will be ready.
- Ted