Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932325AbbBZPJM (ORCPT ); Thu, 26 Feb 2015 10:09:12 -0500 Received: from fieldses.org ([173.255.197.46]:54007 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751597AbbBZPJL (ORCPT ); Thu, 26 Feb 2015 10:09:11 -0500 Date: Thu, 26 Feb 2015 10:09:08 -0500 From: "J. Bruce Fields" To: One Thousand Gnomes Cc: Linus Torvalds , Jeff Layton , "Kirill A. Shutemov" , linux-fsdevel , Linux Kernel Mailing List , Christoph Hellwig , Dave Chinner , Sasha Levin Subject: Re: [GIT PULL] please pull file-locking related changes for v3.20 Message-ID: <20150226150908.GD20495@fieldses.org> References: <20150209055540.2f2a3689@tlielax.poochiereds.net> <20150216133200.GB3270@node.dhcp.inet.fi> <20150216090054.62455465@tlielax.poochiereds.net> <20150217190844.GC27900@fieldses.org> <20150226110046.4bd919ad@lxorguk.ukuu.org.uk> <20150226144500.GC20495@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150226144500.GC20495@fieldses.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1554 Lines: 38 On Thu, Feb 26, 2015 at 09:45:00AM -0500, J. Bruce Fields wrote: > On Thu, Feb 26, 2015 at 11:00:46AM +0000, One Thousand Gnomes wrote: > > On Tue, 17 Feb 2015 11:13:39 -0800 > > Linus Torvalds wrote: > > > > > On Tue, Feb 17, 2015 at 11:08 AM, J. Bruce Fields wrote: > > > > > > > > I agree that it's weird, but I think it's what we're stuck with. > > > > > > And if by "weird" you mean "flock is really not a well-defined or sane > > > interface", I'll agree with you. > > > > > > That said, I'm not at all sure about the "we're stuck with it". We can > > > improve the semantics without anybody noticing, because it's not like > > > anybody could *depend* on the weaker semantics - they needed > > > particular races and timings to hit anyway. > > > > The BSD implementation does not documented such a race, or indeed appear > > to have one. That implies that nothing using flock should have this > > problem. > > Which race are you talking about exactly, and what evidence are you > working from? To clarify: I previously conflated two issues: - the temporary drop of the spinlock in flock_lock_file(). Agreed that that's pointless, and has been fixed. - non-atomic flock upgrades: that's definitely documented behavior on BSD. --b. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/