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=-3.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED, USER_AGENT_GIT 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 59445C46471 for ; Sun, 5 Aug 2018 15:03:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 00C6F21888 for ; Sun, 5 Aug 2018 15:03:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="hyVmZvwm" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 00C6F21888 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726407AbeHERIJ (ORCPT ); Sun, 5 Aug 2018 13:08:09 -0400 Received: from mail.kernel.org ([198.145.29.99]:40722 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726204AbeHERII (ORCPT ); Sun, 5 Aug 2018 13:08:08 -0400 Received: from localhost.localdomain (unknown [49.77.238.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0085521885; Sun, 5 Aug 2018 15:03:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1533481396; bh=/jMPMEXJtcrvTphQV50JbS85kjAtlJEXvumdph8WMgw=; h=From:To:Cc:Subject:Date:From; b=hyVmZvwmMZdC549N3WH2nJK+pKNZYQFnSX50TCctXc6IpQLV12pheb/BfQTXGGIUT J884ErqG6XrC+LAh52ZHGQiZkGSUNbn4BKmgb8Xs9JL8U1gIAORFttvY7D3vftZbQM m9up0/9Rtg0HqaiQur1uy2cU9p/cRs0qiN1DvY7E= From: Chao Yu To: jaegeuk@kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu Subject: [PATCH v2] f2fs: avoid race between zero_range and background GC Date: Sun, 5 Aug 2018 23:02:22 +0800 Message-Id: <20180805150222.9261-1-chao@kernel.org> X-Mailer: git-send-email 2.18.0 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Chao Yu Thread A Background GC - f2fs_zero_range - truncate_pagecache_range - gc_data_segment - get_read_data_page - move_data_page - set_page_dirty - set_cold_data - f2fs_do_zero_range - dn->data_blkaddr = NEW_ADDR; - f2fs_set_data_blkaddr Actually, we don't need to set dirty & checked flag on the page, since all valid data in the page should be zeroed by zero_range(). Use i_gc_rwsem[WRITE] to avoid such race condition. Signed-off-by: Chao Yu --- v2: - decrease i_gc_rwsem lock coverage. fs/f2fs/file.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c index 606c5a215542..bcffb3b608ed 100644 --- a/fs/f2fs/file.c +++ b/fs/f2fs/file.c @@ -1311,8 +1311,6 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len, if (ret) goto out_sem; - truncate_pagecache_range(inode, offset, offset + len - 1); - pg_start = ((unsigned long long) offset) >> PAGE_SHIFT; pg_end = ((unsigned long long) offset + len) >> PAGE_SHIFT; @@ -1342,12 +1340,19 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len, unsigned int end_offset; pgoff_t end; + down_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); + + truncate_pagecache_range(inode, + (loff_t)index << PAGE_SHIFT, + ((loff_t)pg_end << PAGE_SHIFT) - 1); + f2fs_lock_op(sbi); set_new_dnode(&dn, inode, NULL, NULL, 0); ret = f2fs_get_dnode_of_data(&dn, index, ALLOC_NODE); if (ret) { f2fs_unlock_op(sbi); + up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); goto out; } @@ -1356,7 +1361,9 @@ static int f2fs_zero_range(struct inode *inode, loff_t offset, loff_t len, ret = f2fs_do_zero_range(&dn, index, end); f2fs_put_dnode(&dn); + f2fs_unlock_op(sbi); + up_write(&F2FS_I(inode)->i_gc_rwsem[WRITE]); f2fs_balance_fs(sbi, dn.node_changed); -- 2.18.0