On Thu, Mar 29, 2007 at 05:21:26PM +0530, Amit K. Arora wrote:

   int fallocate(int fd, loff_t offset, loff_t len, int mode)

Right now there are only two possible values for mode --- it's not
clear what additional values there will be in the future.

How about two syscalls?  If we decide later on we need something more
complicated we can revisit this and *THEN* add another system call
which may end up being a superset of the other two.

I know that sounds somewhat icky but:

  * it's fairly simple

  * we get nice argument handling on all arches by dropping u32 mode
    (don't we?)

  * syscalls don't really cost a lot to keep about, they do cost in
    terms on maintenance though, but in this case i don't see it being
    all that much of a problem

  * IMO badly/over designed syscalls are going to be a bigger problem
    long term

Given that *NO* single fs in mainline right now can *reliably* use
this functionality for a while maybe whatever solution people come up
with next should sit in -mm for a while?  At least that gives people
exposure to it and a chance to make some changes as once it's merged
to mainline it's pretty hard to change.