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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 48729C433EF for ; Fri, 22 Oct 2021 15:32:39 +0000 (UTC) Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id EA509610A4; Fri, 22 Oct 2021 15:32:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org EA509610A4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.sourceforge.net Received: from [127.0.0.1] (helo=sfs-ml-1.v29.lw.sourceforge.com) by sfs-ml-1.v29.lw.sourceforge.com with esmtp (Exim 4.90_1) (envelope-from ) id 1mdwX7-0005N7-1x; Fri, 22 Oct 2021 15:32:37 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-1.v29.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mdwX6-0005MK-Ew for linux-f2fs-devel@lists.sourceforge.net; Fri, 22 Oct 2021 15:32:36 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: From:References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=vzmn7a/XdwXzsj0OI+skwq6aSHdLz8K8GMedL6eNm0Y=; b=lCkY3HHgL490LC1R9lX2pJYl9D lP6D3Q13JGJRm06eETVQTfBVRVRephgwD5kh+BvQZxcoCVh9OF7kDkSq2aq2+lYEow09zr0aCZZBy e8AWG+vtbpUu2FDHZNy7VluxXHCLv2nQyC4J5T2zeyx10L2ouMi7Qwe28cdiNJTRyQuc=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From:References:Cc:To: Subject:MIME-Version:Date:Message-ID:Sender:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=vzmn7a/XdwXzsj0OI+skwq6aSHdLz8K8GMedL6eNm0Y=; b=ZH59ZKo/beaV/a+M1r+1CuGafb n71btT8TZ4G7ku0eqONIEiLH6XXW+gm7oSkQ9Sl0kW6l48rzwhIfrEs/g2SLCAJ/rWAwXtyS74V37 /tME+v4CIKXSiC4XPEK+5gHo3LqTWnXEt41xZmAJFr6z8N/v/9hb/VTFa31Su93b98GE=; Received: from mail.kernel.org ([198.145.29.99]) by sfi-mx-1.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92.3) id 1mdwX0-00C0v0-9P for linux-f2fs-devel@lists.sourceforge.net; Fri, 22 Oct 2021 15:32:36 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0DCEC6054E; Fri, 22 Oct 2021 15:32:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634916740; bh=dsX++Uq9HxwTDlQDY7ato4NKF0kNAEUBDapYaqRA0mI=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=lQWW/kv4bYwG2eiGsk3PVYg9jXIMXMKfD1qt40pxIisJzhuO9iPyELNTcPrDIMU// ECQ8d9i3TlKupqDUH+GCtLlcdYYrJcWNhBfitlIYYJBJ0roxybxflXr43fn+G2i7pf jfqsWwqGSzJTco7W/4iE4hQ+VOp97sdF9Ww+kWi91vm3wjzGQxZxZ2KHmfujNLKQvy 1Ns3wrxF5xFusbkj8TBUOzXWxc+Gaeq5Gy10uLTThbfYTY100ke9UKU1GnUj4Yv3Z5 1jXHMi96uF3jATU7SHVhhs3zNKBkHktLInR0tgccjaxATjTSJAE2+KQ35nBtAM4MKk gBaue/wr7AXcw== Message-ID: <3ddb4013-8d63-7c00-6fdd-1f21752bd60c@kernel.org> Date: Fri, 22 Oct 2021 23:32:16 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Content-Language: en-US To: Daeho Jeong References: <20211014190503.717830-1-daeho43@gmail.com> From: Chao Yu In-Reply-To: X-Headers-End: 1mdwX0-00C0v0-9P Subject: Re: [f2fs-dev] [PATCH] f2fs: remove circular locking between sb_internal and fs_reclaim X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Daeho Jeong , kernel-team@android.com, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On 2021/10/22 0:44, Daeho Jeong wrote: > There is a deadlock between sb_internal lock (sb_start_intwrite()) and > dquot related lock. > It's because we call f2fs_truncate(), which eventually calls > dquot_initialize(), while holding sb_internal lock. > So, I called dquot_initialize() in advance to make the 2nd calling of > it in f2fs_truncate() ineffective. > This is similar with the thing in f2fs_evict_inode() in inode.c Well, if dquot_initialize() fails in f2fs_drop_inode(), will we still run into deadlock? Thanks, > > Thanks, > > On Thu, Oct 21, 2021 at 5:11 AM Chao Yu wrote: >> >> On 2021/10/15 3:05, Daeho Jeong wrote: >>> From: Daeho Jeong >>> >>> We detected the below circular locking dependency between sb_internal >>> and fs_reclaim. So, removed it by calling dquot_initialize() before >>> sb_start_intwrite(). >>> >>> ====================================================== >>> WARNING: possible circular locking dependency detected >>> ------------------------------------------------------ >>> kswapd0/133 is trying to acquire lock: >>> ffffff80d5fb9680 (sb_internal#2){.+.+}-{0:0}, at: evict+0xd4/0x2f8 >>> >>> but task is already holding lock: >>> ffffffda597c93a8 (fs_reclaim){+.+.}-{0:0}, at: >>> __fs_reclaim_acquire+0x4/0x50 >>> >>> which lock already depends on the new lock. >>> ... >>> other info that might help us debug this: >>> >>> Chain exists of: >>> >>> sb_internal#2 --> &s->s_dquot.dqio_sem --> fs_reclaim >>> >>> Possible unsafe locking scenario: >>> >>> CPU0 CPU1 >>> ---- ---- >>> lock(fs_reclaim); >>> lock(&s->s_dquot.dqio_sem); >>> lock(fs_reclaim); >>> lock(sb_internal#2); >> >> Sorry, I still didn't get the root cause of this deadlock issue, could >> you please explain more about this? >> >> And why calling dquot_initialize() in drop_inode() could break the >> circular locking dependency? >> >> Thanks, >> >>> >>> Signed-off-by: Daeho Jeong >>> --- >>> fs/f2fs/super.c | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c >>> index 86eeb019cc52..a133932333c5 100644 >>> --- a/fs/f2fs/super.c >>> +++ b/fs/f2fs/super.c >>> @@ -1370,6 +1370,8 @@ static int f2fs_drop_inode(struct inode *inode) >>> /* should remain fi->extent_tree for writepage */ >>> f2fs_destroy_extent_node(inode); >>> >>> + dquot_initialize(inode); >>> + >>> sb_start_intwrite(inode->i_sb); >>> f2fs_i_size_write(inode, 0); >>> >>> _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel