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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7D743C433F5 for ; Wed, 8 Dec 2021 14:16:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233376AbhLHOT6 (ORCPT ); Wed, 8 Dec 2021 09:19:58 -0500 Received: from out0.migadu.com ([94.23.1.103]:10960 "EHLO out0.migadu.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233375AbhLHOT6 (ORCPT ); Wed, 8 Dec 2021 09:19:58 -0500 X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1638972981; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=HBDxlLmhIcClgdgclfmBhbzS+yPLXMqj2SXtgQ9pG+w=; b=ceIiYTKic4VVQoRFFYQwFQAIMEL6VMt0B2YRl/UAqm7jqcnQKERhB7QzsHaiPxtuMsLG+U KOd7rBhukqYBoI4I4VUgwprb1kyBOqcl3j2jzecwwRhAFvFWAQVEXvzbDrIfQgk891HDSi 2bEKF+8yXTkeXgE496Y/1fST95n6bWc= From: Guoqing Jiang Subject: Re: [PATCH V2] md: don't unregister sync_thread with reconfig_mutex held To: Paul Menzel , Song Liu , Alasdair Kergon , Mike Snitzer , heinzm@redhat.com, jbrassow@redhat.com Cc: linux-raid , dm-devel@redhat.com, Donald Buczek , it+raid@molgen.mpg.de References: <1613177399-22024-1-git-send-email-guoqing.jiang@cloud.ionos.com> <36a660ed-b995-839e-ac82-dc4ca25ccb8a@molgen.mpg.de> <9f28f6e2-e46a-bfed-09d8-2fec941ea881@cloud.ionos.com> <3f2ad763-6fcb-a652-7131-9e20135a1405@molgen.mpg.de> Message-ID: Date: Wed, 8 Dec 2021 22:16:16 +0800 MIME-Version: 1.0 In-Reply-To: <3f2ad763-6fcb-a652-7131-9e20135a1405@molgen.mpg.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Migadu-Flow: FLOW_OUT X-Migadu-Auth-User: linux.dev Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org On 12/1/21 1:27 AM, Paul Menzel wrote: > >>>>>>> diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c >>>>>>> index cab12b2..0c4cbba 100644 >>>>>>> --- a/drivers/md/dm-raid.c >>>>>>> +++ b/drivers/md/dm-raid.c >>>>>>> @@ -3668,7 +3668,7 @@ static int raid_message(struct dm_target >>>>>>> *ti, unsigned int argc, char **argv, >>>>>>>         if (!strcasecmp(argv[0], "idle") || !strcasecmp(argv[0], >>>>>>> "frozen")) { >>>>>>>                 if (mddev->sync_thread) { >>>>>>>                         set_bit(MD_RECOVERY_INTR, >>>>>>> &mddev->recovery); >>>>>>> -                     md_reap_sync_thread(mddev); >>>>>>> +                     md_reap_sync_thread(mddev, false); >>>>> >>>>> I think we can add mddev_lock() and mddev_unlock() here and then >>>>> we don't >>>>> need the extra parameter? >>>> >>>> I thought it too, but I would prefer get the input from DM people >>>> first. >>>> >>>> @ Mike or Alasdair >>> >>> Hi Mike and Alasdair, >>> >>> Could you please comment on this option: adding mddev_lock() and >>> mddev_unlock() >>> to raid_message() around md_reap_sync_thread()? Add Heinz and Jonathan, could you comment about this? Thanks. >> >> The issue is unfortunately still unresolved (at least Linux 5.10.82). >> How can we move forward? If it is not applicable to change dm-raid, another alternative could be like this --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -9409,8 +9409,12 @@ void md_reap_sync_thread(struct mdev *mddev)         sector_t old_dev_sectors = mddev->dev_sectors;         bool is_reshaped = false; +       if (mddev_is_locked(mddev)) +               mddev_unlock(mddev);         /* resync has finished, collect result */         md_unregister_thread(&mddev->sync_thread); +       if (mddev_is_locked(mddev)) +               mddev_lock(mddev);         if (!test_bit(MD_RECOVERY_INTR, &mddev->recovery) &&             !test_bit(MD_RECOVERY_REQUESTED, &mddev->recovery) &&             mddev->degraded != mddev->raid_disks) { diff --git a/drivers/md/md.h b/drivers/md/md.h index 53ea7a6961de..96a88b7681d6 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h @@ -549,6 +549,11 @@ static inline int mddev_trylock(struct mddev *mddev)  }  extern void mddev_unlock(struct mddev *mddev); +static inline int mddev_is_locked(struct mddev *mddev) +{ +       return mutex_is_locked(&mddev->reconfig_mutex); +} + BTW, it is holiday season,  so people are probably on vacation. Thanks, Guoqing