Re: [Qemu-devel] copy on write-but-no-change

[Rob Landley]

On Friday 07 September 2007 10:40:15 am Luke -Jr wrote:
> I don't believe it's possible to make holes in sparse files explicitly.
> The libc/OS only support it transparently when you jump to the end of a
> file and begin writing there.

Actually, I believe it should finally show up in the 2.6.23 kernel.  Look for 
fadvise(FA_DEALLOCATE)

http://lwn.net/Articles/226710/

Rob
-- 
"One of my most productive days was throwing away 1000 lines of code."
  - Ken Thompson.