Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755925AbYLEAhu (ORCPT ); Thu, 4 Dec 2008 19:37:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752019AbYLEAhl (ORCPT ); Thu, 4 Dec 2008 19:37:41 -0500 Received: from one.firstfloor.org ([213.235.205.2]:47403 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751919AbYLEAhk (ORCPT ); Thu, 4 Dec 2008 19:37:40 -0500 Date: Fri, 5 Dec 2008 01:48:49 +0100 From: Andi Kleen To: Mikulas Patocka Cc: Andi Kleen , linux-kernel@vger.kernel.org, xfs@oss.sgi.com, Alasdair G Kergon , Andi Kleen , Milan Broz Subject: Re: Device loses barrier support (was: Fixed patch for simple barriers.) Message-ID: <20081205004849.GX6703@one.firstfloor.org> References: <20081204100050.GN6703@one.firstfloor.org> <20081204142015.GQ6703@one.firstfloor.org> <20081204145810.GR6703@one.firstfloor.org> <20081204174838.GS6703@one.firstfloor.org> <20081204221551.GV6703@one.firstfloor.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1033 Lines: 27 > And if barriers fail at random points, the user can't turn on disk cache > anyway (he would get data corruption if barrier write failed and hardware I think we already established earlier in the thread that there is no disk corruption > > > I'm wondering, where in fsync() does Linux wait for hardware disk cache to > > > be flushed? Isn't there a bug that fsync() will return before the cache is > > > flushed? I couldn't really find it. The last thing do_fsync calls is > > > filemap_fdatawait and it doesn't do cache flush (blkdev_issue_flush). > > > > At least in fsync() on journaling fs the metadata update should push it. > > > > -Andi > > And what about fdatasync()? I don't know. The surest way to find out is to instrument it and try. -Andi -- ak@linux.intel.com -- 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/