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=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 D3444C38A2A for ; Fri, 8 May 2020 16:10:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AAA7F2173E for ; Fri, 8 May 2020 16:10:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588954254; bh=CngiETS7U8ogJRzhIAr/EkeUvISa1C5VP4Jj6loUtak=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=Zz5gMDMYI+FrIAKrjsFnBDT/LojKZMjx4fDaK+BcWes/biUyERsejsGedKJ4KO0gz SfT/8jmy5aCyEUXL9Dcc8Z2+coQJG+r8ctutAcQwKdrxzx/l+lxdbISee/chfQ8Ax8 Jx0hHEW9nGUjGBZ6LrNhpeuUo2sJnPQIUZs0oBTo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727940AbgEHQKx (ORCPT ); Fri, 8 May 2020 12:10:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:36530 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726771AbgEHQKx (ORCPT ); Fri, 8 May 2020 12:10:53 -0400 Received: from localhost (unknown [104.132.1.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C6A6921473; Fri, 8 May 2020 16:10:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588954252; bh=CngiETS7U8ogJRzhIAr/EkeUvISa1C5VP4Jj6loUtak=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oStbxdglOMtUlQGeVwfj1nbCiFYPbNAyqYsWAckLKAfCrntEbOxHnepG8AU/EuuQP S9Ys7M4l6CEpsTsKd7OZ5UgO6WuMZhMM73CLZu+avs+f4q6nDVoC6LcqkOORyGx2m4 yir+WIq2rwTMo5QWsw757cHq67kWjTtLeBKTFl58= Date: Fri, 8 May 2020 09:10:52 -0700 From: Jaegeuk Kim To: Sayali Lokhande Cc: yuchao0@huawei.com, linux-f2fs-devel@lists.sourceforge.net, stummala@codeaurora.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V4] f2fs: Avoid double lock for cp_rwsem during checkpoint Message-ID: <20200508161052.GA49579@google.com> References: <1588244309-1468-1-git-send-email-sayalil@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1588244309-1468-1-git-send-email-sayalil@codeaurora.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sayali, In order to address the perf regression, how about this? >From 48418af635884803ffb35972df7958a2e6649322 Mon Sep 17 00:00:00 2001 From: Jaegeuk Kim Date: Fri, 8 May 2020 09:08:37 -0700 Subject: [PATCH] f2fs: avoid double lock for cp_rwsem during checkpoint 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: 2049d4fcb057 ("f2fs: avoid multiple node page writes due to inline_data") Signed-off-by: Sayali Lokhande Signed-off-by: Jaegeuk Kim --- fs/f2fs/node.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c index 1db8cabf727ef..626d7daca09de 100644 --- a/fs/f2fs/node.c +++ b/fs/f2fs/node.c @@ -1870,8 +1870,8 @@ int f2fs_sync_node_pages(struct f2fs_sb_info *sbi, goto continue_unlock; } - /* flush inline_data */ - if (is_inline_node(page)) { + /* flush inline_data, if it's not sync path. */ + if (do_balance && is_inline_node(page)) { clear_inline_node(page); unlock_page(page); flush_inline_data(sbi, ino_of_node(page)); -- 2.26.2.645.ge9eca65c58-goog