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=-8.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 9F754C8300A for ; Thu, 30 Apr 2020 10:06:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 75AC22173E for ; Thu, 30 Apr 2020 10:06:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=mg.codeaurora.org header.i=@mg.codeaurora.org header.b="vnImVihw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726793AbgD3KGu (ORCPT ); Thu, 30 Apr 2020 06:06:50 -0400 Received: from mail26.static.mailgun.info ([104.130.122.26]:37802 "EHLO mail26.static.mailgun.info" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726766AbgD3KGu (ORCPT ); Thu, 30 Apr 2020 06:06:50 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1588241209; h=Content-Transfer-Encoding: Content-Type: In-Reply-To: MIME-Version: Date: Message-ID: From: References: Cc: To: Subject: Sender; bh=J1aAaLwfymtTSJ5DCuryIxkiQKiJb3MkkpGzHGgV1tA=; b=vnImVihw6O//LQf4X33MEdiC+8CMX5Mk9MOWrlqjpZAQzRjwX4eGF39G4/pnydfHo/LN0E4h 0w1cjpQFK6Cz4ZUsvDpmJTMIas/e2mgCfcD6P6RcRopzfTT+65SOoHE57M+HVRmUIXEkuekX t9YF9YOo3e7E/J6ca5K65aUm3/I= X-Mailgun-Sending-Ip: 104.130.122.26 X-Mailgun-Sid: WyI0MWYwYSIsICJsaW51eC1rZXJuZWxAdmdlci5rZXJuZWwub3JnIiwgImJlOWU0YSJd Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by mxa.mailgun.org with ESMTP id 5eaaa339.7efc2a3f38b8-smtp-out-n04; Thu, 30 Apr 2020 10:06:49 -0000 (UTC) Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 25DBBC43637; Thu, 30 Apr 2020 10:06:48 +0000 (UTC) Received: from [192.168.0.103] (unknown [183.83.143.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: sayalil) by smtp.codeaurora.org (Postfix) with ESMTPSA id 37D3CC433D2; Thu, 30 Apr 2020 10:06:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 37D3CC433D2 Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: aws-us-west-2-caf-mail-1.web.codeaurora.org; spf=none smtp.mailfrom=sayalil@codeaurora.org Subject: Re: [PATCH V3] f2fs: Avoid double lock for cp_rwsem during checkpoint To: Chao Yu , jaegeuk@kernel.org, linux-f2fs-devel@lists.sourceforge.net Cc: stummala@codeaurora.org, linux-kernel@vger.kernel.org References: <1588179630-22819-1-git-send-email-sayalil@codeaurora.org> <7c68cd6d-d858-f80c-f258-e5e1340b9aa3@huawei.com> From: Sayali Lokhande Message-ID: <4a601e70-8738-df5b-c642-7fd1800026cc@codeaurora.org> Date: Thu, 30 Apr 2020 15:36:42 +0530 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <7c68cd6d-d858-f80c-f258-e5e1340b9aa3@huawei.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 4/30/2020 6:41 AM, Chao Yu wrote: > On 2020/4/30 1:00, Sayali Lokhande wrote: >> There could be a scenario where f2fs_sync_node_pages gets >> called during checkpoint, which in turn tries to flush >> inline data and calls iput(). This results in deadlock as >> iput() tries to hold cp_rwsem, which is already held at the >> beginning by checkpoint->block_operations(). >> >> Call stack : >> >> Thread A Thread B >> f2fs_write_checkpoint() >> - block_operations(sbi) >> - f2fs_lock_all(sbi); >> - down_write(&sbi->cp_rwsem); >> >> - open() >> - igrab() >> - write() write inline data >> - unlink() >> - f2fs_sync_node_pages() >> - if (is_inline_node(page)) >> - flush_inline_data() >> - ilookup() >> page = f2fs_pagecache_get_page() >> if (!page) >> goto iput_out; >> iput_out: >> -close() >> -iput() >> iput(inode); >> - f2fs_evict_inode() >> - f2fs_truncate_blocks() >> - f2fs_lock_op() >> - down_read(&sbi->cp_rwsem); >> >> Fixes: 399368372ed9 ("f2fs: introduce a new global lock scheme") > IMO, it should be > > 2049d4fcb057 ("f2fs: avoid multiple node page writes due to inline_data") > > It brings iput() to checkpoint process for the first time. > > Thanks, Agreed. will update it. >> Signed-off-by: Sayali Lokhande >> --- >> fs/f2fs/checkpoint.c | 10 ++++------ >> 1 file changed, 4 insertions(+), 6 deletions(-) >> >> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c >> index 5ba649e..97b6378 100644 >> --- a/fs/f2fs/checkpoint.c >> +++ b/fs/f2fs/checkpoint.c >> @@ -1219,21 +1219,19 @@ static int block_operations(struct f2fs_sb_info *sbi) >> goto retry_flush_quotas; >> } >> >> -retry_flush_nodes: >> down_write(&sbi->node_write); >> >> if (get_pages(sbi, F2FS_DIRTY_NODES)) { >> up_write(&sbi->node_write); >> + up_write(&sbi->node_change); >> + f2fs_unlock_all(sbi); >> atomic_inc(&sbi->wb_sync_req[NODE]); >> err = f2fs_sync_node_pages(sbi, &wbc, false, FS_CP_NODE_IO); >> atomic_dec(&sbi->wb_sync_req[NODE]); >> - if (err) { >> - up_write(&sbi->node_change); >> - f2fs_unlock_all(sbi); >> + if (err) >> goto out; >> - } >> cond_resched(); >> - goto retry_flush_nodes; >> + goto retry_flush_quotas; >> } >> >> /* >>