posix_fallocate(2)

[mdf at FreeBSD.org]

On Thu, Apr 14, 2011 at 12:35 PM,  <mdf at freebsd.org> wrote:
> For work we need a functionality in our filesystem that is pretty much
> like posix_fallocate(2), so we're using the name and I've added a
> default VOP_ALLOCATE definition that does the right, but dumb, thing.
>
> The most recent mention of this function in FreeBSD was another thread
> lamenting it's failure to exist:
> http://lists.freebsd.org/pipermail/freebsd-ports/2010-February/059268.html
>
> The attached files are the core of the kernel implementation of the
> syscall and a default VOP for any filesystem not supporting
> VOP_ALLOCATE, which allows the syscall to work as expected but in a
> non-performant manner.  I didn't see this syscall in NetBSD or
> OpenBSD, so I plan to add it to the end of our syscall table.

I should note that I have a bunch of unit tests as well, but they're
currently using $WORK's test harness, so I plan to figure out how to
re-write them into the existing prove(1) harness.

Thanks,
matthew

>
> What I wanted to check with -arch about was:
>
> 1) is there still a desire for this syscall?
> 2) is this naive implementation useful enough to serve as a default
> for all filesystems until someone with more knowledge fills them in?
> 3) are there any obvious bugs or missing elements?
>
> Thanks,
> matthew
>