Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758225Ab2BISaw (ORCPT ); Thu, 9 Feb 2012 13:30:52 -0500 Received: from acsinet15.oracle.com ([141.146.126.227]:30248 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752559Ab2BISav (ORCPT ); Thu, 9 Feb 2012 13:30:51 -0500 Date: Thu, 9 Feb 2012 13:30:27 -0500 From: Chris Mason To: Christoph Hellwig Cc: Wu Fengguang , Dave Chinner , Andrew Morton , linux-fsdevel@vger.kernel.org, LKML , Jens Axboe , Li Shaohua Subject: Re: [PATCH] block: remove plugging at buffered write time Message-ID: <20120209183027.GT8384@shiny> Mail-Followup-To: Chris Mason , Christoph Hellwig , Wu Fengguang , Dave Chinner , Andrew Morton , linux-fsdevel@vger.kernel.org, LKML , Jens Axboe , Li Shaohua References: <20120208110143.GA5550@localhost> <20120208232719.GD7479@dastard> <20120209080224.GA28465@localhost> <20120209180635.GA18902@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120209180635.GA18902@infradead.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet22.oracle.com [156.151.31.94] X-CT-RefId: str=0001.0A090202.4F3410CD.00AE,ss=1,re=0.000,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1238 Lines: 29 On Thu, Feb 09, 2012 at 01:06:35PM -0500, Christoph Hellwig wrote: > On Thu, Feb 09, 2012 at 04:02:24PM +0800, Wu Fengguang wrote: > > On Thu, Feb 09, 2012 at 10:27:19AM +1100, Dave Chinner wrote: > > > On Wed, Feb 08, 2012 at 07:01:44PM +0800, Wu Fengguang wrote: > > > > Buffered write(2) is not directly tied to IO, so it's not suitable to > > > > handle plug in generic_file_aio_write(). > > > > > > But generic_sync_write() does issue IO for O_SYNC writes, so unless > > > there is plugging at a lower layer in the writeback code then it > > > appears to me that plugging is still necessary (at least inside the > > > sync branch).... > > > > Good catch! It looks that generic_write_sync() eventually calls into > > vfs_fsync_range() which further calls ->fsync(). We may add plugging > > around it: > > > NAK, please keep the plugging down in the fs, or the libraries used but > not common VFS code. Please, what Christoph said. At least for btrfs plugging here is wrong. -chris -- 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/