On Wed, Nov 25, 2009 at 03:27:26PM +1300, Charles Manning wrote:
> What I have now only fails if a mmap write is followed by a truncate down then 
> truncate up.

I'm not sure if this is relevant, or sheds any light on the situation, but
have you read this article from LWN?

  File holes, races, and mmap()
  http://lwn.net/Articles/357767/

Bye for now,
-- 
Laurence Withers, <l@lwithers.me.uk>               http://www.lwithers.me.uk/