[OpenAFS] Re: Large files with 1.6.0pre2

Russ Allbery rra@stanford.edu
Sat, 05 Mar 2011 20:03:44 -0800

Derrick Brashear <shadow@dementia.org> writes:

> do we know that all the platforms we support large files on deal with
> this correctly? I'd bet not.

Well, pwritev may not be available in a large-file version (or at all),
but any platform that has large file support at all will support
_FILE_OFFSET_BITS.  That was the core of the LFS standard, and basically
everyone who implemented LFS supported it.  I think the only exception is
old HP-UX, where we have a special-case right now to set _FILE64 instead;
we probably shouldn't drop that special case.

I would be mildly surprised if there were platforms implementing LFS and
pwritev that didn't have a large-file version of pwritev.

In any event, AC_SYS_LARGEFILE is at worst harmless.  The main question is
whether we'll have to also avoid pwritev.

There's another question: why did this only affect pwritev and not
everything else?  How are we getting large-file support for open, write,
etc., when we're not using AC_SYS_LARGEFILE?  I see the vol package sets
_FILE_OFFSET_BITS to 64 manually for one specific object, but that can't
be the entirety of our large-file handling....

Russ Allbery (rra@stanford.edu)             <http://www.eyrie.org/~eagle/>