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SubjectRe: [RESEND] [PATCH] VFS: make file->f_pos access atomic on 32bit arch
On Wed, Oct 08, 2008 at 01:35:44PM +1100, Nick Piggin wrote:
> Right you are. That's the fundamental question. The actual details of
> the fix and how likely the race is don't really matter until we
> answer the first question (except to say that the "fix" is never going
> to be free).
> We've lasted this long with the current semantics. So the natural
> reaction to anything that strengthens the semantics now is "why?". If
> we do that then we can basically never return to the weaker semantics.
> So there had better be a really good reason.

And it's worth saying that letter-of-the-standard arguments aren't
necessarily enough. Linux does not honour the POSIX guarantee that
writes are atomic (if they cross page boundaries, it's not certain).
This seems like even more of a corner case to me.

Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."

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