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 776B6C33C9B for ; Tue, 7 Jan 2020 17:07:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4ACC821744 for ; Tue, 7 Jan 2020 17:07:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="Dg5eAnUL" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728358AbgAGRHq (ORCPT ); Tue, 7 Jan 2020 12:07:46 -0500 Received: from aserp2120.oracle.com ([141.146.126.78]:60494 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728236AbgAGRHp (ORCPT ); Tue, 7 Jan 2020 12:07:45 -0500 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 007Gxs1i108694; Tue, 7 Jan 2020 17:07:34 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=TonZdKs5flBwONqESEptkzUdNDu8nb8volKmuzA6Cz0=; b=Dg5eAnULbmvdHQzXt/MZgtHB0R/zWD0HQ+5s3azeZp8EEZ34ay8U8IXHjZGsgK27rehS bb8ffV2JEBwuogOZg4wcANMgdMBKS97CpXpWk7KU7SVlPQgFUWlVHu1DAfnGryIv1LKI M5AvVllmupEsFvrHYTNamVFhNzc87ByL1gWOw0iTmEuPoX1/m7tYqFY+EvYYNZUwGLxG 1Lo8F+6TNJ6Q1EeRhKR2XXV7l75GPDLV1kYwFuGmzfY9nlZh5W1Im1qMYi7elyFGtzp+ gnwn6VDCbHk8N4C5wW46kKsyxAWes1ui6aXftOTsyPgLj2wHtLqD0FgPkvrqcDbM/whH 9A== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by aserp2120.oracle.com with ESMTP id 2xajnpxvme-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 07 Jan 2020 17:07:34 +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 007GxqZk067504; Tue, 7 Jan 2020 17:07:34 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserp3030.oracle.com with ESMTP id 2xcpamx72e-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 07 Jan 2020 17:07:34 +0000 Received: from abhmp0013.oracle.com (abhmp0013.oracle.com [141.146.116.19]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 007H7XOT027070; Tue, 7 Jan 2020 17:07:33 GMT Received: from localhost (/67.169.218.210) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 07 Jan 2020 09:07:33 -0800 Date: Tue, 7 Jan 2020 09:07:31 -0800 From: "Darrick J. Wong" To: Dan Williams Cc: Christoph Hellwig , Vivek Goyal , Dave Chinner , Miklos Szeredi , linux-nvdimm , Linux Kernel Mailing List , "Dr. David Alan Gilbert" , virtio-fs@redhat.com, Stefan Hajnoczi , linux-fsdevel Subject: Re: [PATCH 01/19] dax: remove block device dependencies Message-ID: <20200107170731.GA472641@magnolia> References: <20190821175720.25901-2-vgoyal@redhat.com> <20190826115152.GA21051@infradead.org> <20190827163828.GA6859@redhat.com> <20190828065809.GA27426@infradead.org> <20190828175843.GB912@redhat.com> <20190828225322.GA7777@dread.disaster.area> <20191216181014.GA30106@redhat.com> <20200107125159.GA15745@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9492 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=8.0.1-1911140001 definitions=main-2001070137 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9492 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=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001070137 Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Tue, Jan 07, 2020 at 06:22:54AM -0800, Dan Williams wrote: > On Tue, Jan 7, 2020 at 4:52 AM Christoph Hellwig wrote: > > > > On Mon, Dec 16, 2019 at 01:10:14PM -0500, Vivek Goyal wrote: > > > > Agree. In retrospect it was my laziness in the dax-device > > > > implementation to expect the block-device to be available. > > > > > > > > It looks like fs_dax_get_by_bdev() is an intercept point where a > > > > dax_device could be dynamically created to represent the subset range > > > > indicated by the block-device partition. That would open up more > > > > cleanup opportunities. > > > > > > Hi Dan, > > > > > > After a long time I got time to look at it again. Want to work on this > > > cleanup so that I can make progress with virtiofs DAX paches. > > > > > > I am not sure I understand the requirements fully. I see that right now > > > dax_device is created per device and all block partitions refer to it. If > > > we want to create one dax_device per partition, then it looks like this > > > will be structured more along the lines how block layer handles disk and > > > partitions. (One gendisk for disk and block_devices for partitions, > > > including partition 0). That probably means state belong to whole device > > > will be in common structure say dax_device_common, and per partition state > > > will be in dax_device and dax_device can carry a pointer to > > > dax_device_common. > > > > > > I am also not sure what does it mean to partition dax devices. How will > > > partitions be exported to user space. > > > > Dan, last time we talked you agreed that partitioned dax devices are > > rather pointless IIRC. Should we just deprecate partitions on DAX > > devices and then remove them after a cycle or two? > > That does seem a better plan than trying to force partition support > where it is not needed. Question: if one /did/ have a partitioned DAX device and used kpartx to create dm-linear devices for each partition, will DAX still work through that? --D