Messages in this thread | | | Date | Thu, 9 Oct 2008 14:16:30 +0200 | From | Pavel Machek <> | Subject | Re: [RESEND] [PATCH] VFS: make file->f_pos access atomic on 32bit arch |
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On Tue 2008-10-07 20:59:23, Peter Zijlstra wrote: > On Tue, 2008-10-07 at 10:50 -0700, Andrew Morton wrote: > > On Wed, 8 Oct 2008 03:27:44 +1100 Nick Piggin <nickpiggin@yahoo.com.au> wrote: > > > > So.. is everyone agreed that corrupting f_pos is a bad thing? (serious > > > question) If so, then we should get something like this merged sooner > > > rather than later. > > > > - two threads/processes sharing the same fd > > > > - both appending the same fd > > > > - both hit the small race window right around the time when the file > > flips over a multiple of 4G. > > > > It's pretty damn improbable, and I think we can afford to spend the > > time to get this right in 2.6.29. > > The whole point is that such usage is outside the specification and thus > we don't strictly need to fix this. > > So the question Nick is asking is, do we want to slow down the kernel > for a few broken user-space applications. Esp. since the race doesn't > affect anybody else except the broken users of the file descriptor.
Why is it outside spec?
> IMHO not worth fixing..
I believe we even have append-only flag, similar to immutable, which is used for security...??
-- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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