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=-2.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,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 891ABC433F5 for ; Wed, 29 Aug 2018 07:48:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4B4AF2086D for ; Wed, 29 Aug 2018 07:48:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4B4AF2086D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com 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 S1727795AbeH2Lnh (ORCPT ); Wed, 29 Aug 2018 07:43:37 -0400 Received: from smtp2.provo.novell.com ([137.65.250.81]:42751 "EHLO smtp2.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727099AbeH2Lnh (ORCPT ); Wed, 29 Aug 2018 07:43:37 -0400 Received: from Beta.suse.asia (prv-ext-foundry1int.gns.novell.com [137.65.251.240]) by smtp2.provo.novell.com with ESMTP (NOT encrypted); Wed, 29 Aug 2018 01:47:52 -0600 From: Larry Chen To: mfasheh@suse.com, jlbec@evilplan.org Cc: linux-kernel@vger.kernel.org, ocfs2-devel@oss.oracle.com, akpm@linux-foundation.org Subject: [PATCH] fix crash on ocfs2_duplicate_clusters_by_page Date: Wed, 29 Aug 2018 15:47:40 +0800 Message-Id: <20180829074740.9438-1-lchen@suse.com> X-Mailer: git-send-email 2.13.7 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ocfs2_duplicate_clusters_by_page may crash if one of extent's pages is dirty. When a page has not been written back, it is still in dirty state. If ocfs2_duplicate_clusters_by_page is called against the dirty page, the crash happens. To fix this bug, we can just unlock the page and wait the page until it's not dirty. The following is the buck trace dump: kernel BUG at /root/code/ocfs2/refcounttree.c:2961! [exception RIP: ocfs2_duplicate_clusters_by_page+822] __ocfs2_move_extent+0x80/0x450 [ocfs2] ? __ocfs2_claim_clusters+0x130/0x250 [ocfs2] ocfs2_defrag_extent+0x5b8/0x5e0 [ocfs2] __ocfs2_move_extents_range+0x2a4/0x470 [ocfs2] ocfs2_move_extents+0x180/0x3b0 [ocfs2] ? ocfs2_wait_for_recovery+0x13/0x70 [ocfs2] ocfs2_ioctl_move_extents+0x133/0x2d0 [ocfs2] ocfs2_ioctl+0x253/0x640 [ocfs2] do_vfs_ioctl+0x90/0x5f0 SyS_ioctl+0x74/0x80 do_syscall_64+0x74/0x140 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 Change-log: 1. Once we founce the page is dirty, we do not wait until it's clean, but rather we use write_one_page to write it back 2. write_one_page arguments list changed, adjust and retest this patch. Signed-off-by: Larry Chen --- fs/ocfs2/refcounttree.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c index 7869622af22a..d6022e04c35a 100644 --- a/fs/ocfs2/refcounttree.c +++ b/fs/ocfs2/refcounttree.c @@ -2946,6 +2946,7 @@ int ocfs2_duplicate_clusters_by_page(handle_t *handle, if (map_end & (PAGE_SIZE - 1)) to = map_end & (PAGE_SIZE - 1); +retry: page = find_or_create_page(mapping, page_index, GFP_NOFS); if (!page) { ret = -ENOMEM; @@ -2957,8 +2958,15 @@ int ocfs2_duplicate_clusters_by_page(handle_t *handle, * In case PAGE_SIZE <= CLUSTER_SIZE, This page * can't be dirtied before we CoW it out. */ - if (PAGE_SIZE <= OCFS2_SB(sb)->s_clustersize) - BUG_ON(PageDirty(page)); + if (PAGE_SIZE <= OCFS2_SB(sb)->s_clustersize) { + if (PageDirty(page)) { + /* + * write_on_page will unlock the page on return + */ + ret = write_one_page(page); + goto retry; + } + } if (!PageUptodate(page)) { ret = block_read_full_page(page, ocfs2_get_block); -- 2.13.7