ext3 0.9.13 for linux 2.4.13-pre6

[Andrew Morton]

An ext3 patch for the latest Linus kernel is at

	http://www.uow.edu.au/~andrewm/linux/ext3/

The changes are quite small:

- Tided up some code now that quotas in Linus and -ac kernels are
  synced up.

- Fix a race which can cause a null-pointer deref in ext3_writepage().
  This bug has been there for a long time, but only manifested in
  2.3.13-pre for some reason.

I've tested this pretty hard, every which way.  It looks OK.

There was a report against ext3-for-2.4.10 that mark_buffer_clean()
was being called against an already-clean buffer.  This has not
been reproducable (in later kernels, at least).  If anyone sees
the message "jbd_preclean_buffer_check: clean of clean buffer"
come out, please shout.  This can only happen if ext3 debugging
support is enabled in config.