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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 989AFC4321D for ; Mon, 20 Aug 2018 09:32:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 508D92154B for ; Mon, 20 Aug 2018 09:32:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 508D92154B 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 S1726585AbeHTMrY convert rfc822-to-8bit (ORCPT ); Mon, 20 Aug 2018 08:47:24 -0400 Received: from prv1-mh.provo.novell.com ([137.65.248.33]:51357 "EHLO prv1-mh.provo.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726129AbeHTMrY (ORCPT ); Mon, 20 Aug 2018 08:47:24 -0400 X-Greylist: delayed 1223 seconds by postgrey-1.27 at vger.kernel.org; Mon, 20 Aug 2018 08:47:24 EDT Received: from INET-PRV1-MTA by prv1-mh.provo.novell.com with Novell_GroupWise; Mon, 20 Aug 2018 03:12:12 -0600 Message-Id: <5B7A85DF020000F90002F815@prv1-mh.provo.novell.com> X-Mailer: Novell GroupWise Internet Agent 18.0.2 Date: Mon, 20 Aug 2018 03:11:59 -0600 From: "Gang He" To: , "Lei Chen" , Cc: , Subject: Re: [Ocfs2-devel] [PATCH] fix crash on ocfs2_duplicate_clusters_by_page References: <20180816112426.12218-1-lchen@suse.com> In-Reply-To: <20180816112426.12218-1-lchen@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Larry, >>> On 2018/8/16 at 19:24, in message <20180816112426.12218-1-lchen@suse.com>, Larry Chen wrote: > ocfs2_duplicate_clusters_by_page may crash if an extent's page is dirty. > When a page has not been written back, it is still in dirty state. If at > that moment, ocfs2_duplicate_clusters_by_page is called against this > page, the crash happens. > > To fix this bug, we can just unlock the page and wait the page until > it's not dirty. > > I don't know whether the patch is appropriate, so I need comments, > thanks. > > The following is the core dump: > > kernel BUG at /root/code/ocfs2/refcounttree.c:2961! > __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 > > To: mfasheh@versity.com, > jlbec@evilplan.org > Cc: linux-kernel@vger.kernel.org, > ocfs2-devel@oss.oracle.com, > akpm@linux-foundation.org > > Signed-off-by: Larry Chen > --- > fs/ocfs2/refcounttree.c | 10 ++++++++-- > 1 file changed, 8 insertions(+), 2 deletions(-) > > diff --git a/fs/ocfs2/refcounttree.c b/fs/ocfs2/refcounttree.c > index 7869622af22a..ee3b9dbbc310 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 +2958,13 @@ 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)) { > + unlock_page(page); Here, if we find this page is dirty, could we write this page to the disk initiatively? rather than wait for the page become clean by VM mechanism. Thanks Gang > + cond_resched(); > + goto retry; > + } > + } > > if (!PageUptodate(page)) { > ret = block_read_full_page(page, ocfs2_get_block); > -- > 2.13.7 > > > _______________________________________________ > Ocfs2-devel mailing list > Ocfs2-devel@oss.oracle.com > https://oss.oracle.com/mailman/listinfo/ocfs2-devel