From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261458AbUBUBFu (ORCPT ); Fri, 20 Feb 2004 20:05:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261460AbUBUBFu (ORCPT ); Fri, 20 Feb 2004 20:05:50 -0500 Received: from fw.osdl.org ([65.172.181.6]:58029 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S261458AbUBUBFt (ORCPT ); Fri, 20 Feb 2004 20:05:49 -0500 Date: Fri, 20 Feb 2004 17:10:54 -0800 (PST) From: Linus Torvalds To: Jamie Lokier cc: Ingo Molnar , Tridge , Al Viro , "H. Peter Anvin" , Kernel Mailing List Subject: Re: explicit dcache <-> user-space cache coherency, sys_mark_dir_clean(), O_CLEAN In-Reply-To: <20040221003831.GB10928@mail.shareable.org> Message-ID: References: <20040219081027.GB4113@mail.shareable.org> <20040219163838.GC2308@mail.shareable.org> <20040219182948.GA3414@mail.shareable.org> <20040220120417.GA4010@elte.hu> <20040220173307.GF8994@mail.shareable.org> <20040221003831.GB10928@mail.shareable.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 21 Feb 2004, Jamie Lokier wrote: > > Eh? The flag and notification operations are set and tested > under the inode semaphore, when fcntl() is called. Doesn't matter. Because you will drop the inode semaphore before you actually create a new file. So you'll alway shave a window open for a race. That's what Ingo's O_CLEAN thing did. An di fyou do Ingo's O_CLEAN, then there's no point to notifiers in the first place - Ingo's algorithm works regardless of them (it had other problems, but that's another issue and just requires a bit of extending on the basic concept). So why do you care about dnotify? It doesn't help at all once you have O_CLEAN (or equivalent). Linus