Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756124AbZCXF5T (ORCPT ); Tue, 24 Mar 2009 01:57:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752533AbZCXF5F (ORCPT ); Tue, 24 Mar 2009 01:57:05 -0400 Received: from cantor.suse.de ([195.135.220.2]:48429 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750806AbZCXF5D (ORCPT ); Tue, 24 Mar 2009 01:57:03 -0400 From: Nikanth Karthikesan Organization: suse.de To: Jens Axboe Subject: Re: [PATCH] Block - Honour barrier requests in loop driver Date: Tue, 24 Mar 2009 11:24:35 +0530 User-Agent: KMail/1.10.3 (Linux/2.6.27.19-3.2-default; KDE/4.1.3; x86_64; ; ) Cc: Christoph Hellwig , Gerd Hoffmann , Constantine Sapuntzakis , Miklos Szeredi , nikanth@gmail.com, linux-kernel@vger.kernel.org References: <200903171417.16760.knikanth@suse.de> <20090317190905.GA28816@infradead.org> <200903181028.20689.knikanth@suse.de> In-Reply-To: <200903181028.20689.knikanth@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200903241124.36223.knikanth@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2627 Lines: 91 On Wednesday 18 March 2009 10:28:20 Nikanth Karthikesan wrote: > On Wednesday 18 March 2009 00:39:05 Christoph Hellwig wrote: > > On Tue, Mar 17, 2009 at 05:39:49PM +0530, Nikanth Karthikesan wrote: > > > + if (!file->f_op || !file->f_op->fsync) { > > > + ret = -EOPNOTSUPP; > > > + goto out; > > > + } > > > > file->f_op is never zero, so you can remove the checks for that. > > Otherwise looks good. > > Thanks for reviewing. I've removed that check. > > Jens, Can you merge this? > Hi Jens Did you get to look at this? Can you merge this? Thanks Nikanth > > Honour barrier requests in the loop back block device driver. > In case of barrier bios, flush the backing file once before processing the > barrier and once after to guarantee ordering. In case of filesystems that > does not support fsync, barrier bios would be failed with -EOPNOTSUPP. > > Signed-off-by: Nikanth Karthikesan > > --- > > diff --git a/drivers/block/loop.c b/drivers/block/loop.c > index bf03455..cac7894 100644 > --- a/drivers/block/loop.c > +++ b/drivers/block/loop.c > @@ -474,10 +474,35 @@ static int do_bio_filebacked(struct loop_device *lo, > struct bio *bio) int ret; > > pos = ((loff_t) bio->bi_sector << 9) + lo->lo_offset; > - if (bio_rw(bio) == WRITE) > + > + if (bio_rw(bio) == WRITE) { > + int barrier = bio_barrier(bio); > + struct file *file = lo->lo_backing_file; > + > + if (barrier) { > + if (unlikely(!file->f_op->fsync)) { > + ret = -EOPNOTSUPP; > + goto out; > + } > + > + ret = vfs_fsync(file, file->f_path.dentry, 0); > + if (unlikely(ret)) { > + ret = -EIO; > + goto out; > + } > + } > + > ret = lo_send(lo, bio, pos); > - else > + > + if (barrier && !ret) { > + ret = vfs_fsync(file, file->f_path.dentry, 0); > + if (unlikely(ret)) > + ret = -EIO; > + } > + } else > ret = lo_receive(lo, bio, lo->lo_blocksize, pos); > + > +out: > return ret; > } > > @@ -825,6 +850,10 @@ static int loop_set_fd(struct loop_device *lo, fmode_t > mode, blk_queue_make_request(lo->lo_queue, loop_make_request); > lo->lo_queue->queuedata = lo; > lo->lo_queue->unplug_fn = loop_unplug; > + if (!(lo_flags & LO_FLAGS_READ_ONLY) && file->f_op && > + file->f_op->fsync) { > + blk_queue_ordered(lo->lo_queue, QUEUE_ORDERED_DRAIN, NULL); > + } > > set_capacity(lo->lo_disk, size); > bd_set_size(bdev, size << 9); -- 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/