Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932776AbXBTSlQ (ORCPT ); Tue, 20 Feb 2007 13:41:16 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932973AbXBTSlP (ORCPT ); Tue, 20 Feb 2007 13:41:15 -0500 Received: from agminet01.oracle.com ([141.146.126.228]:50968 "EHLO agminet01.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932776AbXBTSlP (ORCPT ); Tue, 20 Feb 2007 13:41:15 -0500 In-Reply-To: <1171988988.6271.26.camel@heimdal.trondhjem.org> References: <20070219203527.20419.68418.sendpatchset@tetsuo.zabbo.net> <20070219215048.GI6133@think.oraclecorp.com> <20070220002109.GG31205@kvack.org> <1171987310.6271.23.camel@heimdal.trondhjem.org> <20070220160854.GO6133@think.oraclecorp.com> <1171988988.6271.26.camel@heimdal.trondhjem.org> Mime-Version: 1.0 (Apple Message framework v752.3) Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Message-Id: <528148DD-0533-4D82-A242-25A4C5D1A977@oracle.com> Cc: Chris Mason , Benjamin LaHaise , "Ananiev, Leonid I" , linux-aio@kvack.org, linux-kernel@vger.kernel.org, Suparna bhattacharya , Andrew Morton Content-Transfer-Encoding: 7bit From: Zach Brown Subject: Re: [PATCH] aio: propogate post-EIOCBQUEUED errors to completion event Date: Tue, 20 Feb 2007 10:40:03 -0800 To: Trond Myklebust X-Mailer: Apple Mail (2.752.3) X-Brightmail-Tracker: AAAAAQAAAAI= X-Whitelist: TRUE Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 965 Lines: 25 >> There are some strange O_DIRECT corner cases in here such that the >> 'last >> writer' may actually be a 'last reader' and winning can mean have >> a copy >> of the page in page cache older than the copy on disk. > > As long as it is marked dirty so that it eventually gets synced to > disk, > it shouldn't matter. No, Chris is pointing out that an an O_DIRECT write can leave clean read pages in the page cache. All it takes is giving a source buffer for the write which is an mmap ()ed apeture of the region that is being written to. If you get the offsets right you can get the get_user_pages() down in fs/direct-io.c will populate the page cache before the actual O_DIRECT write gets to it. - z - 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/