From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.cn.fujitsu.com ([183.91.158.132]:14143 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751024AbeAVNGb (ORCPT ); Mon, 22 Jan 2018 08:06:31 -0500 Date: Mon, 22 Jan 2018 21:06:23 +0800 From: Lu Fengqi To: Nikolay Borisov CC: , Zygo Blaxell , Subject: Re: [PATCH] btrfs: remove spurious WARN_ON(ref->count) in find_parent_nodes Message-ID: <20180122130622.GB532@fnst.localdomain> References: <20180121190848.7wmps6q5ng6b42ki@hungrycats.org> <20180122033452.GA532@fnst.localdomain> <9151459e-8db2-bdd1-a21e-23d730cb52a4@suse.com> <87ed4d9c-9af4-4425-5a35-b0ccd9305e76@cn.fujitsu.com> <377c6852-6617-b4e0-5e69-60a9566bd894@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" In-Reply-To: <377c6852-6617-b4e0-5e69-60a9566bd894@suse.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On Mon, Jan 22, 2018 at 02:38:42PM +0200, Nikolay Borisov wrote: > > >On 22.01.2018 14:19, Lu Fengqi wrote: >> On 01/22/2018 04:46 PM, Nikolay Borisov wrote: >>> >>> >>> On 22.01.2018 05:34, Lu Fengqi wrote: >>>> According to my bisect result, The frequency of the warning occurrence >>>> increased to the detectable degree after this patch >>> >>> That sentence implies that even before Ed's patch it was possible to >>> trigger those warnings, is that true? Personally I've never seen such >>> warnings while executing btrfs/004. How do you configure the filesystem >>> for the test runs? >>> >> >> Just only default mount option. >> >> ➜  xfstests-dev git:(master) for i in $(seq 1 100); do echo $i; if ! >> sudo ./check btrfs/004; then break; fi; done >> 1 >> >> FSTYP         -- btrfs >> >> PLATFORM      -- Linux/x86_64 sarch 4.15.0-rc9 >> >> MKFS_OPTIONS  -- /dev/vdd1 >> >> MOUNT_OPTIONS -- /dev/vdd1 /mnt/scratch >> >> >> >> >> btrfs/004 47s ... 49s >> >> Ran: btrfs/004 >> >> Passed all 1 tests >> >> >> >> >> 2 >> >> FSTYP         -- btrfs >> >> PLATFORM      -- Linux/x86_64 sarch 4.15.0-rc9 >> >> MKFS_OPTIONS  -- /dev/vdd1 >> >> MOUNT_OPTIONS -- /dev/vdd1 /mnt/scratch >> >> >> >> >> btrfs/004 49s ... 52s >> >> _check_dmesg: something found in dmesg (see >> /home/luke/workspace/xfstests-dev/results//btrfs/004.dmesg) >> >> Ran: btrfs/004 >> >> Failures: btrfs/004 >> >> Failed 1 of 1 tests >> >> The probability of this warning appearing is rather low, and I only >> encountered 52 warnings when I looped 1008 times btrfs/004 for 20 hours >> in 4.15-rc6 (IOW, the probability is nearly 5%). So you want to trigger >> warning also need more luck or patience. > >Thanks but is this before or after the mentioned commit below? > After this commit. The bisect condition I use to locate this commit is to repeat btrfs/004 20 times without warning (This may not be accurate enough, can only be used as a reference). Maybe Zygo has found a finer way to reproduce it, so he reproduce this warning more frequently than me. > >> >>>> 86d5f9944252 ("btrfs: convert prelimary reference tracking to use >>>> rbtrees") >>>> is committed. I understand that this does not mean that this patch >>>> caused >>>> the problem, but maybe Edmund can give us some help, so I added him >>>> to the >>>> recipient. >>> >>> >> >> > > -- Thanks, Lu