Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754168Ab0K3QmG (ORCPT ); Tue, 30 Nov 2010 11:42:06 -0500 Received: from verein.lst.de ([213.95.11.210]:47286 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753717Ab0K3QmD (ORCPT ); Tue, 30 Nov 2010 11:42:03 -0500 Date: Tue, 30 Nov 2010 17:41:24 +0100 From: Christoph Hellwig To: "Darrick J. Wong" Cc: Jens Axboe , "Theodore Ts'o" , Neil Brown , Andreas Dilger , Alasdair G Kergon , Jan Kara , Mike Snitzer , linux-kernel , linux-raid@vger.kernel.org, Keith Mannthey , dm-devel@redhat.com, Mingming Cao , Tejun Heo , linux-ext4@vger.kernel.org, Ric Wheeler , Christoph Hellwig , Josef Bacik Subject: Re: [PATCH v6 0/4] ext4: Coordinate data-only flush requests sent by fsync Message-ID: <20101130164124.GA30858@lst.de> References: <20101129220536.12401.16581.stgit@elm3b57.beaverton.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20101129220536.12401.16581.stgit@elm3b57.beaverton.ibm.com> User-Agent: Mutt/1.3.28i X-Spam-Score: 0 () Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1770 Lines: 47 FYI, here's an updated version of my patch to not run pure flushes that also works on SCSI/ATA and not just virtio. I suspect the patch alone might not be enough, but together with a variant of Neil's suggestion might do the trick, with my patch taking care of the highend-devices and Neil's scheme of taking care of stupid SATA disks. Index: linux-2.6/block/blk-flush.c =================================================================== --- linux-2.6.orig/block/blk-flush.c 2010-11-30 17:27:33.108254088 +0100 +++ linux-2.6/block/blk-flush.c 2010-11-30 17:27:38.790004333 +0100 @@ -143,6 +143,17 @@ struct request *blk_do_flush(struct requ unsigned skip = 0; /* + * Just issue pure flushes directly. + */ + if (!blk_rq_sectors(rq)) { + if (!do_preflush) { + __blk_end_request_all(rq, 0); + return NULL; + } + return rq; + } + + /* * Special case. If there's data but flush is not necessary, * the request can be issued directly. * Index: linux-2.6/drivers/scsi/scsi_lib.c =================================================================== --- linux-2.6.orig/drivers/scsi/scsi_lib.c 2010-11-30 17:27:33.120254298 +0100 +++ linux-2.6/drivers/scsi/scsi_lib.c 2010-11-30 17:27:38.791003634 +0100 @@ -1060,7 +1060,7 @@ int scsi_setup_blk_pc_cmnd(struct scsi_d * that does not transfer data, in which case they may optionally * submit a request without an attached bio. */ - if (req->bio) { + if (req->bio && !(req->cmd_flags & REQ_FLUSH)) { int ret; BUG_ON(!req->nr_phys_segments); -- 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/