From patchwork Wed Jan 17 18:17:57 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mikulas Patocka X-Patchwork-Id: 13522082 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8FE342374B for ; Wed, 17 Jan 2024 18:18:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705515485; cv=none; b=nsE07Q06DX64+UvyzPT9aS3Ro5pH4XjSlYI1UCY7LPOfo2vDWSLhE6FCaUga+JccYJSJ9WEHG9RdXIeKpqDvDcwMibWyD9O+oBoPgcAFxAQqB8wA+oAuSWQI8aNoQkG2Ek3eK0uTNWhih952ygc4XxAg2ApJ4RkzwDS51ryINl8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705515485; c=relaxed/simple; bh=odaoLRetP6yq9eTrctHLbHR7C/CXSfIABfBoEMR3r/I=; h=DKIM-Signature:Received:X-MC-Unique:Received:Received:Received: Received:Date:From:To:cc:Subject:In-Reply-To:Message-ID:References: MIME-Version:Content-Type:X-Scanned-By; b=CipKZxRiEVx6Hpzr5y0/ztbd/RINo2fNqknb5/TFbutkmiMiw07XJ58aa6YDNUZas+I5SyFol5IIeJlX/23LftHRWIWz2zuRXtLsdsIwPBE3d/yEUsdM3TEGM+G5WPXbKg71QDH/Z1Dl3DbkfEdyRZWUu/PsF/izCtfo2pTXas0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=XNTnbldM; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="XNTnbldM" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1705515482; 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: in-reply-to:in-reply-to:references:references; bh=OQbrENSM13PTlCIUi4M0i7iy9OOjiGDINAdzr/zFb8Q=; b=XNTnbldMn3ibj/shZiOsLs7bM/c1WwlTIocBOXHGey8bGoUwDBer1Rc6QFyGo73xB/nYSY TWDenFgBs63yXbHSaWUupMusF4qPoCIXnJjznesGfEW/mMfcAdNpaVHxGROldCgTyJcI+l gHLTwqjaJRms6GGbi8DRxhlzeJiC2VQ= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-587-gmWMPmWgONCymp9Oh6vp4A-1; Wed, 17 Jan 2024 13:17:58 -0500 X-MC-Unique: gmWMPmWgONCymp9Oh6vp4A-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id CF37A885626; Wed, 17 Jan 2024 18:17:57 +0000 (UTC) Received: from file1-rdu.file-001.prod.rdu2.dc.redhat.com (unknown [10.11.5.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id C6E9640C6EB9; Wed, 17 Jan 2024 18:17:57 +0000 (UTC) Received: by file1-rdu.file-001.prod.rdu2.dc.redhat.com (Postfix, from userid 12668) id BDF2C30C039C; Wed, 17 Jan 2024 18:17:57 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by file1-rdu.file-001.prod.rdu2.dc.redhat.com (Postfix) with ESMTP id BD1973FB50; Wed, 17 Jan 2024 19:17:57 +0100 (CET) Date: Wed, 17 Jan 2024 19:17:57 +0100 (CET) From: Mikulas Patocka To: Yu Kuai , Song Liu , David Jeffery , Li Nan cc: dm-devel@lists.linux.dev, linux-raid@vger.kernel.org, Mike Snitzer , Heinz Mauelshagen , Benjamin Marzinski Subject: [PATCH 1/7] md: Revert fa2bbff7b0b4 ("md: synchronize flush io with array reconfiguration") In-Reply-To: Message-ID: <2c29cbd4-736d-2f23-2bc-636881c150d6@redhat.com> References: Precedence: bulk X-Mailing-List: linux-raid@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.2 The commit fa2bbff7b0b4 breaks the LVM2 test shell/integrity-caching.sh, so let's revert it. sysrq: Show Blocked State task:lvm state:D stack:0 pid:8275 tgid:8275 ppid:1373 flags:0x00000002 Call Trace: __schedule+0x228/0x570 ? __percpu_ref_switch_mode+0xb7/0x1b0 schedule+0x29/0xa0 mddev_suspend+0xec/0x1a0 [md_mod] ? housekeeping_test_cpu+0x30/0x30 dm_table_postsuspend_targets+0x34/0x50 [dm_mod] __dm_destroy+0x1c5/0x1e0 [dm_mod] ? table_clear+0xa0/0xa0 [dm_mod] dev_remove+0xd4/0x110 [dm_mod] ctl_ioctl+0x2e1/0x570 [dm_mod] dm_ctl_ioctl+0x5/0x10 [dm_mod] __x64_sys_ioctl+0x85/0xa0 do_syscall_64+0x5d/0x1a0 entry_SYSCALL_64_after_hwframe+0x46/0x4e Signed-off-by: Mikulas Patocka Fixes: fa2bbff7b0b4 ("md: synchronize flush io with array reconfiguration") --- drivers/md/md.c | 21 ++++++--------------- 1 file changed, 6 insertions(+), 15 deletions(-) Index: linux-2.6/drivers/md/md.c =================================================================== --- linux-2.6.orig/drivers/md/md.c +++ linux-2.6/drivers/md/md.c @@ -543,9 +543,6 @@ static void md_end_flush(struct bio *bio rdev_dec_pending(rdev, mddev); if (atomic_dec_and_test(&mddev->flush_pending)) { - /* The pair is percpu_ref_get() from md_flush_request() */ - percpu_ref_put(&mddev->active_io); - /* The pre-request flush has finished */ queue_work(md_wq, &mddev->flush_work); } @@ -565,7 +562,12 @@ static void submit_flushes(struct work_s rdev_for_each_rcu(rdev, mddev) if (rdev->raid_disk >= 0 && !test_bit(Faulty, &rdev->flags)) { + /* Take two references, one is dropped + * when request finishes, one after + * we reclaim rcu_read_lock + */ struct bio *bi; + atomic_inc(&rdev->nr_pending); atomic_inc(&rdev->nr_pending); rcu_read_unlock(); @@ -577,6 +579,7 @@ static void submit_flushes(struct work_s atomic_inc(&mddev->flush_pending); submit_bio(bi); rcu_read_lock(); + rdev_dec_pending(rdev, mddev); } rcu_read_unlock(); if (atomic_dec_and_test(&mddev->flush_pending)) @@ -629,18 +632,6 @@ bool md_flush_request(struct mddev *mdde /* new request after previous flush is completed */ if (ktime_after(req_start, mddev->prev_flush_start)) { WARN_ON(mddev->flush_bio); - /* - * Grab a reference to make sure mddev_suspend() will wait for - * this flush to be done. - * - * md_flush_reqeust() is called under md_handle_request() and - * 'active_io' is already grabbed, hence percpu_ref_is_zero() - * won't pass, percpu_ref_tryget_live() can't be used because - * percpu_ref_kill() can be called by mddev_suspend() - * concurrently. - */ - WARN_ON(percpu_ref_is_zero(&mddev->active_io)); - percpu_ref_get(&mddev->active_io); mddev->flush_bio = bio; bio = NULL; }