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=-6.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS autolearn=unavailable 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 9C3C8C04AB4 for ; Sat, 11 May 2019 00:59:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 675BB217D7 for ; Sat, 11 May 2019 00:59:22 +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="JR3F2drF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728348AbfEKA7V (ORCPT ); Fri, 10 May 2019 20:59:21 -0400 Received: from mail-oi1-f196.google.com ([209.85.167.196]:32794 "EHLO mail-oi1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728064AbfEKA7V (ORCPT ); Fri, 10 May 2019 20:59:21 -0400 Received: by mail-oi1-f196.google.com with SMTP id m204so5821232oib.0 for ; Fri, 10 May 2019 17:59:20 -0700 (PDT) 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=cl42dZaKPdWPXIrbH2C5qTFgM5gCSynPhXLIFVqa36M=; b=JR3F2drFoXseIQNDe33GWiE73pjKGHV2B+ZvDgnMGVjCLxOFIDvA+J2M/UovbYCnvV YcuxiRV4p1HMaTBSOYebaH3fsVxx/ol7Wtq6ZpE6/Gk1IBXROdqbBeu5MDQMRwwVcRah m9Qjvj1EU8HgsmsPflXbrp5Vw906510cI+DXtJRIWjFfNagGxWdGiXAeQF1hyIkdtmMT 32kIvIJCS08/uOxfO80bXjH93DKhiS1SMnc1m4KGF7ma2My4ftVxbek5TCV+Tx8pP9Eg MJhTlP53ahTMQYspd6lsWtec5GjwwOjEr4TA+HSjHeNVwNiPPO4FWDnfuEaCMgG0/X9d 2Zaw== 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=cl42dZaKPdWPXIrbH2C5qTFgM5gCSynPhXLIFVqa36M=; b=ez65nu1yMH/PcIlUsDl1YGetHxH1ZcNf0QONgXyaKSTjiugehvCBUaB/ShDIhoazwA 9PIDoJ9mi9gz2vOk8d+BNBLtZhC/tDW6+OF/js/2TmgLvsHoXBt79d13NEZf5/Yx9Itm 7sOpQ6eOir+zztw1GMaYagr7LnclFXsxs4ExuoNqF5MKiVzqgQGU79xORPg9LTaWOHu0 9ATSCOXVLo/DbLZSwoieH5Yf5g2EGErlUsEqLko6cufdV75EdeGEBf+/YpwTAyIFkRZR zg8J/vGiqRoGJLWyBRjtSzGLpvNExDLxynBXtZRc23VksxKlSEuZG5jdXNC1o/xsaDoD 3c1A== X-Gm-Message-State: APjAAAVZkMZ0oouxNNPXWCsA3PtBgbzx0D6p7Q245T8jgpYOt51pa6qU yPpMiBhlxwXJfNnBrxwLJ10UTybmjY0WA0pvMazmLg== X-Google-Smtp-Source: APXvYqxd5L2Nvbw7B4301QM480ldUecZ6yt4es0ATqbCcPph8SnTzi7vakiTbRG5uoFRT6lPjWaHfX+1q4uJu4AYewU= X-Received: by 2002:aca:f512:: with SMTP id t18mr3998026oih.0.1557536360283; Fri, 10 May 2019 17:59:20 -0700 (PDT) MIME-Version: 1.0 References: <20190510155202.14737-1-pagupta@redhat.com> <20190510155202.14737-4-pagupta@redhat.com> <864186878.28040999.1557535549792.JavaMail.zimbra@redhat.com> In-Reply-To: <864186878.28040999.1557535549792.JavaMail.zimbra@redhat.com> From: Dan Williams Date: Fri, 10 May 2019 17:59:08 -0700 Message-ID: Subject: Re: [PATCH v8 3/6] libnvdimm: add dax_dev sync flag To: Pankaj Gupta Cc: linux-nvdimm , Linux Kernel Mailing List , virtualization@lists.linux-foundation.org, KVM list , linux-fsdevel , Linux ACPI , Qemu Developers , linux-ext4 , linux-xfs , Ross Zwisler , Vishal L Verma , Dave Jiang , "Michael S. Tsirkin" , Jason Wang , Matthew Wilcox , "Rafael J. Wysocki" , Christoph Hellwig , Len Brown , Jan Kara , "Theodore Ts'o" , Andreas Dilger , "Darrick J. Wong" , lcapitulino@redhat.com, Kevin Wolf , Igor Mammedov , jmoyer , Nitesh Narayan Lal , Rik van Riel , Stefan Hajnoczi , Andrea Arcangeli , David Hildenbrand , david , cohuck@redhat.com, Xiao Guangrong , Paolo Bonzini , Adam Borowski , yuval shaia , jstaron@google.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 10, 2019 at 5:45 PM Pankaj Gupta wrote: > > > > > > > > > This patch adds 'DAXDEV_SYNC' flag which is set > > > for nd_region doing synchronous flush. This later > > > is used to disable MAP_SYNC functionality for > > > ext4 & xfs filesystem for devices don't support > > > synchronous flush. > > > > > > Signed-off-by: Pankaj Gupta > > > --- > > > drivers/dax/bus.c | 2 +- > > > drivers/dax/super.c | 13 ++++++++++++- > > > drivers/md/dm.c | 3 ++- > > > drivers/nvdimm/pmem.c | 5 ++++- > > > drivers/nvdimm/region_devs.c | 7 +++++++ > > > include/linux/dax.h | 8 ++++++-- > > > include/linux/libnvdimm.h | 1 + > > > 7 files changed, 33 insertions(+), 6 deletions(-) > > [..] > > > diff --git a/drivers/md/dm.c b/drivers/md/dm.c > > > index 043f0761e4a0..ee007b75d9fd 100644 > > > --- a/drivers/md/dm.c > > > +++ b/drivers/md/dm.c > > > @@ -1969,7 +1969,8 @@ static struct mapped_device *alloc_dev(int minor) > > > sprintf(md->disk->disk_name, "dm-%d", minor); > > > > > > if (IS_ENABLED(CONFIG_DAX_DRIVER)) { > > > - dax_dev = alloc_dax(md, md->disk->disk_name, &dm_dax_ops); > > > + dax_dev = alloc_dax(md, md->disk->disk_name, &dm_dax_ops, > > > + DAXDEV_F_SYNC); > > > > Apologies for not realizing this until now, but this is broken. > > Imaging a device-mapper configuration composed of both 'async' > > virtio-pmem and 'sync' pmem. The 'sync' flag needs to be unified > > across all members. I would change this argument to '0' and then > > arrange for it to be set at dm_table_supports_dax() time after > > validating that all components support synchronous dax. > > o.k. Need to set 'DAXDEV_F_SYNC' flag after verifying all the target > components support synchronous DAX. > > Just a question, If device mapper configuration have composed of both > virtio-pmem or pmem devices, we want to configure device mapper for async flush? If it's composed of both then, yes, it needs to be async flush at the device-mapper level. Otherwise MAP_SYNC will succeed and fail to trigger fsync on the host file when necessary for the virtio-pmem backed portion of the device-mapper device.