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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 2F47FC33C9E for ; Tue, 7 Jan 2020 14:23:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F0E7021744 for ; Tue, 7 Jan 2020 14:23:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=intel-com.20150623.gappssmtp.com header.i=@intel-com.20150623.gappssmtp.com header.b="IntyA5IC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728322AbgAGOXG (ORCPT ); Tue, 7 Jan 2020 09:23:06 -0500 Received: from mail-oi1-f196.google.com ([209.85.167.196]:39887 "EHLO mail-oi1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728316AbgAGOXF (ORCPT ); Tue, 7 Jan 2020 09:23:05 -0500 Received: by mail-oi1-f196.google.com with SMTP id a67so17815944oib.6 for ; Tue, 07 Jan 2020 06:23:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=r3VJe/dxyES65jnKtxYvETSNTHRiCAT6fnUUzfyEBsw=; b=IntyA5ICPEcRthqRYPCmMbZcDUdsPJKB41XMg3aNHyS8R6cuHoUT2CPYMdsXtRhIV/ LE4AcTadPsbgzvkcanUbj/feghWprHupsWmFBAPc7sYF+VAsmKBx0fZyJQK8bF8M1Psc 370rbvXm8e9yiT13+D5wg9K9mjUTdZdQ9TNUaJGocfOBIb2O4l3RX+l6g6lrQRLR542K uq6u075ZxqWd1dtGOT1YwXlKc+p25Z2v9ktm+IMQk7DdS4ccYqbvvQwR3hNsxwzI7ML7 uZQ0x6Z/8r+EpXB5udA1qIlwP1zqd7XKjywpXRr4ylCkyezT+6v9gNmT4LaYtbSFwB4R bikA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=r3VJe/dxyES65jnKtxYvETSNTHRiCAT6fnUUzfyEBsw=; b=iquEwUKKVFh0MDXCxWdnyAh29n5Rd/fsKSEvLKJ544lAe0DHpIkxRytbEUyUAVSlJa TeKT6oEA54ATXOa6ejMhTumuWpyOEnW2LJW+utMJK426A1/dBTwFupYtYJ6ZgI2DR2RY +BLaiCWf4JU68vy3ACVrYU5muzORkEJYYN3rf4SDXPj7OIE/XAeTt8qVl/hisU8rg1XF QyEeMZ9jUEXkWsFMDYWa4i9ou/sQ0sUgbNc8XQxXAzgyZLUDunZG6Rr6JMHb7xM6c1Zd JFKb029aQhX+5QoW6fxG+1EJMu0amxR8OUGPrOY4qRBQ+sHkmK0wek3K/S0yG6MPN5aS 9ZDA== X-Gm-Message-State: APjAAAVC4HfqTDAGs4dNnjf0YM0kzoCavAf+4IAp2FCyz5WYQg+JwvqF 2ESNIFeMYl4GzAsc8daRZI/CBpLNthXv2Ac+q5Iw5w== X-Google-Smtp-Source: APXvYqw+M12ZkKSJLTKleOTV1+IDlcbTBO8wNYejP3Rd62JSmbodZTAR2/rj6LbHMWOXB71wX7xzQYargDcyrZtNksM= X-Received: by 2002:a05:6808:b37:: with SMTP id t23mr7383807oij.149.1578406985047; Tue, 07 Jan 2020 06:23:05 -0800 (PST) MIME-Version: 1.0 References: <20190821175720.25901-1-vgoyal@redhat.com> <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> In-Reply-To: <20200107125159.GA15745@infradead.org> From: Dan Williams Date: Tue, 7 Jan 2020 06:22:54 -0800 Message-ID: Subject: Re: [PATCH 01/19] dax: remove block device dependencies To: Christoph Hellwig Cc: Vivek Goyal , Dave Chinner , Miklos Szeredi , linux-nvdimm , Linux Kernel Mailing List , "Dr. David Alan Gilbert" , virtio-fs@redhat.com, Stefan Hajnoczi , linux-fsdevel Content-Type: text/plain; charset="UTF-8" Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org 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.