Re: [PATCH v4] compat: Fix read() of 2GB and more on Mac OS X

[Linus Torvalds <torvalds@linux-foundation.org>]

On Mon, Aug 19, 2013 at 10:16 AM, Junio C Hamano <gitster@pobox.com> wrote:
> Linus Torvalds <torvalds@linux-foundation.org> writes:
>
> The same argument applies to xwrite(), but currently we explicitly
> catch EINTR and EAGAIN knowing that on sane systems these are the
> signs that we got interrupted.
>
> Do we catch EINVAL unconditionally in the same codepath?

No, and we shouldn't. If EINVAL happens, it will keep happening.

But with the size limiter, it doesn't matter, since we won't hit the
OS X braindamage.

> Could
> EINVAL on saner systems mean completely different thing (like our
> caller is passing bogus parameters to underlying read/write, which
> is a program bug we would want to catch)?

Yes. Even on OS X, it means that - it's just that OS X notion of what
is "bogus" is pure crap. But the thing is, looping on EINVAL would be
wrong even on OS X, since unless you change the size, it will keep
happening forever.

But with the "limit IO to 8MB" (or whatever) patch, the issue is moot.
If you get an EINVAL, it will be due to something else being horribly
horribly wrong.

                 Linus