> You do that by never writing to the hole, but lseek()ing to the next part
> you want to write.

I'm sure there is also a way of making a hole in an existing file.

> Hm, which makes me think, that maybe we want SEEK_HOLE, which will be
> equivalent to SEEK_CUR if the filesystem doesn't know about holes, and 
> relative to the end of the next hole otherwise.

That isn't the right place, seek is (probably) handled well above
the VOP layer.  A fcntl() or ioctl() would be more appropriate.

	David

-- 
David Laight: david@l8s.co.uk