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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,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 C3F1CC3A5A7 for ; Mon, 2 Sep 2019 17:01:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9E83F206BB for ; Mon, 2 Sep 2019 17:01:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="lMpG+CXZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726457AbfIBRB2 (ORCPT ); Mon, 2 Sep 2019 13:01:28 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:43444 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726275AbfIBRB2 (ORCPT ); Mon, 2 Sep 2019 13:01:28 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x82GxJeO069743; Mon, 2 Sep 2019 17:01:17 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2019-08-05; bh=SFDxJjAViLlQmwB4JcX+fQxI4Y3TvOk4g/U34IKF6kA=; b=lMpG+CXZBDZLNfvs+NLV40xbtKu2055QexHQVRUpiH3GhUxWtvgzEOKzhfVk9JkNBFMy nxtXbyY2yc02saIccVFBoNB9kJb4urakjmGrJFyijzCRKW0IhaSqgMmRL38NSwuWgqNj XDbVTMJKAEd+/AgBmBhPhszRYSk97AR3jWD3y+xtiLw68rcug8gzktHOMrTx3x7Bahk0 PWi5ZJeEgZqypPi+kBG8gLxD6HuqOXt1x5A7M4zmtio0Hb2RF4HZz1Z58153V2nAyfOV 5B2ZPHKKEgS8JuDMpS1eoh2qaC5556FRzuCDJbm3Heg26kLo+lAv7khyDr2lH/OK120A HQ== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2130.oracle.com with ESMTP id 2us70ar0wf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 02 Sep 2019 17:01:17 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x82Gw8eZ195303; Mon, 2 Sep 2019 17:01:17 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserp3030.oracle.com with ESMTP id 2urww6nnqm-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 02 Sep 2019 17:01:16 +0000 Received: from abhmp0022.oracle.com (abhmp0022.oracle.com [141.146.116.28]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id x82H19WB008126; Mon, 2 Sep 2019 17:01:09 GMT Received: from localhost (/10.159.145.213) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Mon, 02 Sep 2019 10:01:09 -0700 Date: Mon, 2 Sep 2019 10:01:09 -0700 From: "Darrick J. Wong" To: Christoph Hellwig Cc: Goldwyn Rodrigues , linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org, david@fromorbit.com, riteshh@linux.ibm.com, Goldwyn Rodrigues Subject: Re: [PATCH 03/15] iomap: Read page from srcmap for IOMAP_COW Message-ID: <20190902170109.GD568270@magnolia> References: <20190901200836.14959-1-rgoldwyn@suse.de> <20190901200836.14959-4-rgoldwyn@suse.de> <20190902163124.GC6263@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190902163124.GC6263@lst.de> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9368 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=873 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1909020191 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9368 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=932 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1909020191 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Sep 02, 2019 at 06:31:24PM +0200, Christoph Hellwig wrote: > On Sun, Sep 01, 2019 at 03:08:24PM -0500, Goldwyn Rodrigues wrote: > > > + iomap_assert(!(iomap->flags & IOMAP_F_BUFFER_HEAD)); > > + iomap_assert(srcmap->type == IOMAP_HOLE || srcmap->addr > 0); > > 0 can be a valid address in various file systems, so I don't think we > can just exclude it. Then again COWing from a hole seems pointless, > doesn't it? XFS does that if you set a cowextsize hint and a speculative cow preallocation ends up covering a hole. Granted I don't think there's much point in reading from a COW fork extent to fill in an unaligned buffered write since it /should/ just end up zero-filling the pagecache regardless of fork... but I don't see much harm in doing that. --D > So just check for addr != IOMAP_NULL_ADDR here? > > > > > @@ -961,7 +966,7 @@ iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, > > if (IS_DAX(inode)) > > status = iomap_dax_zero(pos, offset, bytes, iomap); > > else > > - status = iomap_zero(inode, pos, offset, bytes, iomap); > > + status = iomap_zero(inode, pos, offset, bytes, iomap, srcmap); > > This introduces an > 80 character line.