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 4C925C77B7A for ; Tue, 13 Jun 2023 08:04:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240792AbjFMIEQ (ORCPT ); Tue, 13 Jun 2023 04:04:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55438 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238986AbjFMIEK (ORCPT ); Tue, 13 Jun 2023 04:04:10 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 749781BF5 for ; Tue, 13 Jun 2023 01:03:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1686643388; 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=V2WAoXU2sO6i7ouZ+ltrXmzd4T/KwU8+agEZUhVJ2/A=; b=ickTAITODDrOK26altYURzBFHLg6v6uksNQvyX5zVveecCRfUIyAGxXSeG+e+h9NlaBCyr LcOkbddI6CFDVuYznSopO0/0lmwsF6kKcDBpe5bhWtYx2rAizyXO72hD8mkoDfEifAKqqA q+5F9xhENQRUvd91haOMzOGKE4IVqbs= Received: from mail-oi1-f200.google.com (mail-oi1-f200.google.com [209.85.167.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-222-CRNTVE69Pd64BByUyBLhKA-1; Tue, 13 Jun 2023 04:03:04 -0400 X-MC-Unique: CRNTVE69Pd64BByUyBLhKA-1 Received: by mail-oi1-f200.google.com with SMTP id 5614622812f47-39ca0a35e21so2206055b6e.2 for ; Tue, 13 Jun 2023 01:03:04 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686643384; x=1689235384; h=content-transfer-encoding:in-reply-to:from:references:cc:to:subject :user-agent:mime-version:date:message-id:x-gm-message-state:from:to :cc:subject:date:message-id:reply-to; bh=V2WAoXU2sO6i7ouZ+ltrXmzd4T/KwU8+agEZUhVJ2/A=; b=gwAv05XcQp0Gi6Kr+4uc6+9jnPnLLD/RGiEoU4mMyoXs5Z0SDem+vMtjioQRttHKTv ivuXJmdLFnCSunkoPWCK/S/oVkQTE18215VUsFVEuMOqMOPD1SwWCZheD0TTqjSYm78D zVFmEObDNkAcNFMHDP6IB7tCkpqLLKf6r3od/3rny84OqgoKKWdSh92uFPlVD1cEqUED GgqJZON5okT2ICFFkAJF39rQf+egeZk2BBlFKfCOeqDFZgkddO8jNETFPIeJB6176Ld5 FjygXWiRoJJWXPyufWrlhkCH2jd8x8TVxtYVDrK1HJrTZszD29tKzUQxBKZ46wmv9uOS ydkA== X-Gm-Message-State: AC+VfDxzLb5G0uw8ZcMldAY2w0kmpteROPHDq8hq/BgtNnBpEL3BcuKU IxTnNljGaNDl2C1AxSseaWCPRQbRS2cxDB3HZiOPTplY4+GtI1k56MO+TtllO8+02piENBqAUyd t5ixD1MnNXjwV0sbRdUgr7g== X-Received: by 2002:a05:6808:221c:b0:39a:5e92:f459 with SMTP id bd28-20020a056808221c00b0039a5e92f459mr7996120oib.38.1686643383905; Tue, 13 Jun 2023 01:03:03 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ7xUDHntHnuiUM8nQFbipVkqgakxXsx7HwJmcyUfwoHuTXrCOl6qzVaRfoSHzNgRHa7Z0rmLw== X-Received: by 2002:a05:6808:221c:b0:39a:5e92:f459 with SMTP id bd28-20020a056808221c00b0039a5e92f459mr7996106oib.38.1686643383607; Tue, 13 Jun 2023 01:03:03 -0700 (PDT) Received: from [10.72.13.126] ([43.228.180.230]) by smtp.gmail.com with ESMTPSA id h13-20020a17090a3d0d00b0025954958e06sm9336256pjc.18.2023.06.13.01.02.57 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 13 Jun 2023 01:03:03 -0700 (PDT) Message-ID: Date: Tue, 13 Jun 2023 16:02:51 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.11.2 Subject: Re: [dm-devel] [PATCH -next v2 2/6] md: refactor action_store() for 'idle' and 'frozen' To: Yu Kuai , guoqing.jiang@linux.dev, agk@redhat.com, snitzer@kernel.org, dm-devel@redhat.com, song@kernel.org Cc: yi.zhang@huawei.com, yangerkun@huawei.com, linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org, yukuai3@huawei.com References: <20230529132037.2124527-1-yukuai1@huaweicloud.com> <20230529132037.2124527-3-yukuai1@huaweicloud.com> From: Xiao Ni In-Reply-To: <20230529132037.2124527-3-yukuai1@huaweicloud.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org 在 2023/5/29 下午9:20, Yu Kuai 写道: > From: Yu Kuai > > Prepare to handle 'idle' and 'frozen' differently to fix a deadlock, there > are no functional changes except that MD_RECOVERY_RUNNING is checked > again after 'reconfig_mutex' is held. Can you explain more about why it needs to check MD_RECOVERY_RUNNING again here? > > Signed-off-by: Yu Kuai > --- > drivers/md/md.c | 61 ++++++++++++++++++++++++++++++++++++------------- > 1 file changed, 45 insertions(+), 16 deletions(-) > > diff --git a/drivers/md/md.c b/drivers/md/md.c > index 9b97731e1fe4..23e8e7eae062 100644 > --- a/drivers/md/md.c > +++ b/drivers/md/md.c > @@ -4755,6 +4755,46 @@ action_show(struct mddev *mddev, char *page) > return sprintf(page, "%s\n", type); > } > > +static void stop_sync_thread(struct mddev *mddev) > +{ > + if (!test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) > + return; > + > + if (mddev_lock(mddev)) > + return; > + > + /* > + * Check again in case MD_RECOVERY_RUNNING is cleared before lock is > + * held. > + */ > + if (!test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) { > + mddev_unlock(mddev); > + return; > + } > + > + if (work_pending(&mddev->del_work)) > + flush_workqueue(md_misc_wq); > + > + if (mddev->sync_thread) { > + set_bit(MD_RECOVERY_INTR, &mddev->recovery); > + md_reap_sync_thread(mddev); > + } > + > + mddev_unlock(mddev); > +} > + > +static void idle_sync_thread(struct mddev *mddev) > +{ > + clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); > + stop_sync_thread(mddev); > +} > + > +static void frozen_sync_thread(struct mddev *mddev) > +{ > + set_bit(MD_RECOVERY_FROZEN, &mddev->recovery); > + stop_sync_thread(mddev); > +} > + > static ssize_t > action_store(struct mddev *mddev, const char *page, size_t len) > { > @@ -4762,22 +4802,11 @@ action_store(struct mddev *mddev, const char *page, size_t len) > return -EINVAL; > > > - if (cmd_match(page, "idle") || cmd_match(page, "frozen")) { > - if (cmd_match(page, "frozen")) > - set_bit(MD_RECOVERY_FROZEN, &mddev->recovery); > - else > - clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery); > - if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery) && > - mddev_lock(mddev) == 0) { > - if (work_pending(&mddev->del_work)) > - flush_workqueue(md_misc_wq); > - if (mddev->sync_thread) { > - set_bit(MD_RECOVERY_INTR, &mddev->recovery); > - md_reap_sync_thread(mddev); > - } > - mddev_unlock(mddev); > - } > - } else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) > + if (cmd_match(page, "idle")) > + idle_sync_thread(mddev); > + else if (cmd_match(page, "frozen")) > + frozen_sync_thread(mddev); > + else if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) > return -EBUSY; > else if (cmd_match(page, "resync")) > clear_bit(MD_RECOVERY_FROZEN, &mddev->recovery);