From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4F5BFC32750 for ; Mon, 5 Aug 2019 00:23:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 290A32086D for ; Mon, 5 Aug 2019 00:23:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726869AbfHEAXf (ORCPT ); Sun, 4 Aug 2019 20:23:35 -0400 Received: from mail105.syd.optusnet.com.au ([211.29.132.249]:52259 "EHLO mail105.syd.optusnet.com.au" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726666AbfHEAXe (ORCPT ); Sun, 4 Aug 2019 20:23:34 -0400 Received: from dread.disaster.area (pa49-181-167-148.pa.nsw.optusnet.com.au [49.181.167.148]) by mail105.syd.optusnet.com.au (Postfix) with ESMTPS id B51742AD02C; Mon, 5 Aug 2019 10:23:32 +1000 (AEST) Received: from dave by dread.disaster.area with local (Exim 4.92) (envelope-from ) id 1huQcn-0004z2-Cd; Mon, 05 Aug 2019 10:13:17 +1000 Date: Mon, 5 Aug 2019 10:13:17 +1000 From: Dave Chinner To: Goldwyn Rodrigues Cc: linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org, hch@lst.de, darrick.wong@oracle.com, ruansy.fnst@cn.fujitsu.com, Goldwyn Rodrigues Subject: Re: [PATCH 05/13] btrfs: Add CoW in iomap based writes Message-ID: <20190805001317.GG7689@dread.disaster.area> References: <20190802220048.16142-1-rgoldwyn@suse.de> <20190802220048.16142-6-rgoldwyn@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190802220048.16142-6-rgoldwyn@suse.de> User-Agent: Mutt/1.10.1 (2018-07-13) X-Optus-CM-Score: 0 X-Optus-CM-Analysis: v=2.2 cv=D+Q3ErZj c=1 sm=1 tr=0 cx=a_idp_d a=gu9DDhuZhshYSb5Zs/lkOA==:117 a=gu9DDhuZhshYSb5Zs/lkOA==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=kj9zAlcOel0A:10 a=FmdZ9Uzk2mMA:10 a=iox4zFpeAAAA:8 a=7-415B0cAAAA:8 a=xrbE8zg4DYH3kasu_qsA:9 a=Pi3r_Vvt8M2xccad:21 a=-2u5YDMPb6Z7_WoB:21 a=CjuIK1q_8ugA:10 a=WzC6qhA0u3u7Ye7llzcV:22 a=biEYGPWJfzWAr4FL6Ov7:22 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Fri, Aug 02, 2019 at 05:00:40PM -0500, Goldwyn Rodrigues wrote: > From: Goldwyn Rodrigues > > Set iomap->type to IOMAP_COW and fill up the source map in case > the I/O is not page aligned. ..... > static void btrfs_buffered_page_done(struct inode *inode, loff_t pos, > unsigned copied, struct page *page, > struct iomap *iomap) > @@ -188,6 +217,7 @@ static int btrfs_buffered_iomap_begin(struct inode *inode, loff_t pos, > int ret; > size_t write_bytes = length; > struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb); > + size_t end; > size_t sector_offset = pos & (fs_info->sectorsize - 1); > struct btrfs_iomap *bi; > > @@ -255,6 +285,17 @@ static int btrfs_buffered_iomap_begin(struct inode *inode, loff_t pos, > iomap->private = bi; > iomap->length = round_up(write_bytes, fs_info->sectorsize); > iomap->offset = round_down(pos, fs_info->sectorsize); > + end = pos + write_bytes; > + /* Set IOMAP_COW if start/end is not page aligned */ > + if (((pos & (PAGE_SIZE - 1)) || (end & (PAGE_SIZE - 1)))) { > + iomap->type = IOMAP_COW; > + ret = get_iomap(inode, pos, length, srcmap); > + if (ret < 0) > + goto release; I suspect you didn't test this case, because.... > + } else { > + iomap->type = IOMAP_DELALLOC; > + } > + > iomap->addr = IOMAP_NULL_ADDR; > iomap->type = IOMAP_DELALLOC; The iomap->type is overwritten here and so IOMAP_COW will never be seen by the iomap infrastructure... Cheers, Dave. -- Dave Chinner david@fromorbit.com