From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mondschein.lichtvoll.de ([194.150.191.11]:40758 "EHLO mail.lichtvoll.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759059AbaGXStj convert rfc822-to-8bit (ORCPT ); Thu, 24 Jul 2014 14:49:39 -0400 From: Martin Steigerwald To: Chris Mason Cc: linux-btrfs@vger.kernel.org, Cody P Schafer , Marc MERLIN Subject: Re: BTRFS hang with 3.16-rc5 (and also with 3.16-rc4) Date: Thu, 24 Jul 2014 20:49:37 +0200 Message-ID: <1557956.045aK4K0qS@merkaba> In-Reply-To: <53D11F2B.1070008@fb.com> References: <1502954.OtX3SzjMKZ@merkaba> <1809953.ithLVmijbn@merkaba> <53D11F2B.1070008@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Sender: linux-btrfs-owner@vger.kernel.org List-ID: Am Donnerstag, 24. Juli 2014, 10:58:51 schrieb Chris Mason: > On 07/23/2014 06:47 PM, Martin Steigerwald wrote: > > Am Dienstag, 15. Juli 2014, 17:08:27 schrieb Martin Steigerwald: > >> Am Dienstag, 15. Juli 2014, 09:21:40 schrieb Chris Mason: > >>> On 07/14/2014 05:58 PM, Martin Steigerwald wrote: > >>>> Am Montag, 14. Juli 2014, 16:12:22 schrieb Chris Mason: > >>>>> On 07/14/2014 11:10 AM, Martin Steigerwald wrote: > >>>>>> Am Montag, 14. Juli 2014, 17:04:22 schrieben Sie: > >>>>>>> Hi! > >>>>>>> > >>>>>>> While with 3.16-rc3 and rc4 I didn´t have a BTRFS hang in several > >>>>>>> days > >>>>>>> of > >>>>>>> usage, with 3-16-rc5 I had a hang again. Less than a hour since > >>>>>>> booting > >>>>>>> it. > >>>>>>> > >>>>>>> Since the hang bug I and others had with 3.15 and upto 3.16-rc2 > >>>>>>> usually > >>>>>>> didn´t happen that quickly after boot and since backtrace looks a > >>>>>>> bit > >>>>>>> different from what I have in memory, I post this in a new thread. > >>>>>>> See thread "Blocked tasks on 3.15.1" for a discussion of previous > >>>>>>> hang > >>>>>>> issues. > >>>>>> > >>>>>> Probably good to add some basic information on the filesystem: > >>>>> Do you have compression enabled? I wasn't able to nail down the > >>>>> 3.15.1 > >>>>> hang before vacation attacked me, but I'm hoping to track it down > >>>>> today. > >>>> > >>>> Yes. I have. > >>>> > >>>> It just hung again while I was playing PlaneShift. > >>>> > >>>> Back to 3.16-rc4 as rc5 seems to be broke here. > >>> > >>> The btrfs hang you're hitting goes back to 3.15. So 3.16-rc4 vs rc5 > >>> shouldn't be a factor. Are you hitting other problems with 3.16? > >> > >> So far for this day 3.16-rc4 behaves nicely. With 3.16-rc5 I had a BTRFS > >> hang twice yesterday. 3.16-rc4 before also behaved nicely for several > >> days > >> or well about a week here. > > > > 3.16-rc4 now hung as well… > > Liu Bo has a promising patch: > > https://patchwork.kernel.org/patch/4618421/ > > Please give it a shot. There's a second deadlock reading the free space > cache, I'm still working on that one too. Now running 3.16-rc6 + current git + this patch. It may take some time tough cause during compiling the kernel BTRFS hung again, which caused loss of KDE Baloo desktop search file index and parts of a mail I wrote in KMail. Since the patch mentioned ENOSPC issues but the filesystem has enough free space according to df I shrunk the trees with btrfs balance start -musage=50 /home btrfs balance start -musage=50 /home merkaba:~> btrfs fi sh /home Label: 'home' uuid: […] Total devices 2 FS bytes used 124.05GiB devid 1 size 160.00GiB used 150.00GiB path /dev/mapper/msata-home devid 2 size 160.00GiB used 150.00GiB path /dev/dm-3 As I bet that the error is more likely to happen when trees occupy all space, it may take some time till it happens again. Well its growing slowly already: merkaba:~> btrfs fi df /home Data, RAID1: total=146.97GiB, used=121.84GiB System, RAID1: total=32.00MiB, used=48.00KiB Metadata, RAID1: total=4.00GiB, used=2.62GiB unknown, single: total=512.00MiB, used=0.00 merkaba:~> btrfs fi sh /home Label: 'home' uuid: […] Total devices 2 FS bytes used 124.46GiB devid 1 size 160.00GiB used 151.00GiB path /dev/dm-0 devid 2 size 160.00GiB used 151.00GiB path /dev/mapper/sata-home Btrfs v3.14.1 I wonder why ENOSPC conditions happens with that much space inside trees free. Were they just too fragmented? To me merkaba:~> LANG=C df -hT /home Filesystem Type Size Used Avail Use% Mounted on /dev/dm-0 btrfs 320G 249G 69G 79% /home is a quite healthy free space margin. Well, lets see how this goes. I hope it can be fixed soon as it causes loss of recently saved data and generally locks up a machine running KDE desktop quite quickly on a BTRFS hang. Ciao, -- Martin 'Helios' Steigerwald - http://www.Lichtvoll.de GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7