From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([59.151.112.132]:48758 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753324AbbIQJjG convert rfc822-to-8bit (ORCPT ); Thu, 17 Sep 2015 05:39:06 -0400 Subject: Re: kernel BUG at linux-4.2.0/fs/btrfs/extent-tree.c:1833 on rebalance To: =?UTF-8?Q?St=c3=a9phane_Lesimple?= References: <9c864637fe7676a8b7badc5ddd7a4e0c@all.all> <2c00c4b7c15e424659fb2e810170e32e@all.all> <55F83181.9010201@fb.com> <532aadf0f92d08d3d2b274173548aee1@all.all> <55F9486F.4040302@googlemail.com> <0973de930ee87e102c533c719807b748@all.all> <55FA2D9A.1060405@cn.fujitsu.com> <55FA60C5.5090002@cn.fujitsu.com> <7a6f2d794fb6cbf7d598b92e3470201c@all.all> CC: From: Qu Wenruo Message-ID: <55FA759E.6030707@cn.fujitsu.com> Date: Thu, 17 Sep 2015 16:11:10 +0800 MIME-Version: 1.0 In-Reply-To: <7a6f2d794fb6cbf7d598b92e3470201c@all.all> Content-Type: text/plain; charset="utf-8"; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: Stéphane Lesimple wrote on 2015/09/17 10:02 +0200: > Le 2015-09-17 08:42, Qu Wenruo a écrit : >> Stéphane Lesimple wrote on 2015/09/17 08:11 +0200: >>> Le 2015-09-17 05:03, Qu Wenruo a écrit : >>>> Stéphane Lesimple wrote on 2015/09/16 22:41 +0200: >>>>> Le 2015-09-16 22:18, Duncan a écrit : >>>>>> Stéphane Lesimple posted on Wed, 16 Sep 2015 15:04:20 +0200 as >>>>>> excerpted: >>>>>> >>>>> >>>>> Well actually it's the (d) option ;) >>>>> I activate the quota feature for only one reason : being able to track >>>>> down how much space my snapshots are taking. >>>> >>>> Yeah, that's completely one of the ideal use case of btrfs qgroup. >>>> >>>> But I'm quite curious about the btrfsck error report on qgroup. >>>> >>>> If btrfsck report such error, it means either I'm too confident about >>>> the recent qgroup accounting rework, or btrfsck has some bug which I >>>> didn't take much consideration during the kernel rework. >>>> >>>> Would you please provide the full result of previous btrfsck with >>>> qgroup error? >>> >>> Sure, I've saved the log somewhere just in case, here your are : >>> >>> [...] >> Thanks for your log, pretty interesting result. >> >> BTW, did you enabled qgroup from old kernel earlier than 4.2-rc1? >> If so, I would be much relaxed as they can be the problem of old kernels. > > The mkfs.btrfs was done under 3.19, but I'm almost sure I enabled quota > under 4.2.0 precisely. My kern.log tends to confirm that (looking for > 'qgroup scan completed'). Emmm, seems I need to pay more attention on this case now. Any info about the workload for this btrfs fs? > >> If it's OK for you, would you please enable quota after reproducing >> the bug and use for sometime and recheck it? > > Sure, I've just reproduced the bug twice as I wanted, and posted the > info, so now I've cancelled the balance and I can reenable quota. Will > do it under 4.3.0-rc1. I'll keep you posted if btrfsck complains about > it in the following days. > > Regards, > Thanks for your patience and detailed report. But I still have another question, did you do any snapshot deletion after quota enabled? (I'll assume you did it, as there are a lot of backup snapshot, old ones should be already deleted) That's one of the known bug and Mark is working on it actively. If you delete non-empty snapshot a lot, then I'd better add a hot fix to mark qgroup inconsistent after snapshot delete, and trigger a rescan if possible. Thanks, Qu