The fsx-linux hole fill failure problem was caused by
generic_file_aio_write_nolock() not handling the partial DIO write
correctly.  Here's a patch lets DIO do the partial write, and the fallback
to buffered is done (correctly) for what is left.  This fixes the hole
filling without retrying the entire i/o.  This patch also applies to
2.6.7-rc3 with some offset.

I tested this (on ext3) with
fsx-linux -l 500000 -r 4096 -t 4096 -w 4096 -Z -N 10000 junk  -R -W
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>