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 9AF2FC3A5A5 for ; Tue, 3 Sep 2019 14:56:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 72E5B22D6D for ; Tue, 3 Sep 2019 14:56:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Mx6msCtH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729721AbfICO4z (ORCPT ); Tue, 3 Sep 2019 10:56:55 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:53414 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728679AbfICO4y (ORCPT ); Tue, 3 Sep 2019 10:56:54 -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 x83ErpU0139258; Tue, 3 Sep 2019 14:56:43 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=J1/XR8SIYBwnS7qUVqN/+gnZ5pU/aly9Tp9KElNL18w=; b=Mx6msCtHFfoUOOGoKlGXGLohgPLtb4ZK4CjhKxFiEv21aYyvEOZC1qBY0PGo0F9guLtt 0VM6LuSK2oycz7w6vKlwh1jDJ/VxgFaUpNjH9Pf1TY1TxOue5/y3rDDf2haBPo0iMtGs pT8r+IXITq06LUxYUd2hVfuTWckjNz+dvhtf4TWVlODYG5yXpRENcCd5rmC1p5Q6SkkJ eisutsMvgEfWVq25uf/76ePEvD2sc9DUR8l4I3/qg6cCo7edKsJ2RtclM62zNpOtkTHB KZy7y6/4qu49XKqbCda4CXfB9jqwgXx2gRQOiKW4LBR6VY7Qk+eyKEx6ky5WnllhmTIg PA== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by userp2130.oracle.com with ESMTP id 2ussxpr6ke-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 03 Sep 2019 14:56:43 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id x83ErWH6088076; Tue, 3 Sep 2019 14:56:43 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3020.oracle.com with ESMTP id 2us4we0507-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 03 Sep 2019 14:56:43 +0000 Received: from abhmp0002.oracle.com (abhmp0002.oracle.com [141.146.116.8]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id x83Euf4V023738; Tue, 3 Sep 2019 14:56:42 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 03 Sep 2019 07:56:41 -0700 Date: Tue, 3 Sep 2019 07:56:44 -0700 From: "Darrick J. Wong" To: Goldwyn Rodrigues Cc: Christoph Hellwig , linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org, david@fromorbit.com, riteshh@linux.ibm.com, Goldwyn Rodrigues Subject: Re: [PATCH 02/15] iomap: Use a IOMAP_COW/srcmap for a read-modify-write I/O Message-ID: <20190903145644.GE5340@magnolia> References: <20190901200836.14959-1-rgoldwyn@suse.de> <20190901200836.14959-3-rgoldwyn@suse.de> <20190902163104.GB6263@lst.de> <20190903140536.5ak7phk5oydkqmx2@fiona> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190903140536.5ak7phk5oydkqmx2@fiona> 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=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1909030157 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=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1909030157 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, Sep 03, 2019 at 09:05:36AM -0500, Goldwyn Rodrigues wrote: > On 18:31 02/09, Christoph Hellwig wrote: > > On Sun, Sep 01, 2019 at 03:08:23PM -0500, Goldwyn Rodrigues wrote: > > > --- a/include/linux/iomap.h > > > +++ b/include/linux/iomap.h > > > @@ -37,6 +37,7 @@ struct vm_fault; > > > #define IOMAP_MAPPED 0x03 /* blocks allocated at @addr */ > > > #define IOMAP_UNWRITTEN 0x04 /* blocks allocated at @addr in unwritten state */ > > > #define IOMAP_INLINE 0x05 /* data inline in the inode */ > > > +#define IOMAP_COW 0x06 /* copy data from srcmap before writing */ > > > > I don't think IOMAP_COW can be a type - it is a flag given that we > > can do COW operations that allocate normal written extents (e.g. for > > direct I/O or DAX) and for delayed allocations. > > > > Ah.. we have come a full circle on this one. From going to a flag, to a type, > and now back to flag. Personally, I like COW to be a flag, because we are > doing a write, just doining extra steps which should be a flag. > From previous objections, using two iomaps should help the cause and we > can not worry about bloating. Heh, ok, let's do a cow flag. Thank you for driving the consensus. :) (Sorry it took so long while we went around in circles.) Also, I'm going on vacation starting Friday at noon PDT, so please have the three patches that touch fs/iomap/ in before 7am Friday. (Assuming you're not making drastic changes to your iomap changes, they've tested ok so far.) --D > > -- > Goldwyn