Messages in this thread | | | Date | Tue, 7 Oct 2008 20:52:09 -0600 | From | Matthew Wilcox <> | Subject | Re: [RESEND] [PATCH] VFS: make file->f_pos access atomic on 32bit arch |
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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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