On Mon, Oct 05, 2009 at 07:10:55PM +0200, Johannes Hirte
wrote:> Am Montag 05 Oktober 2009 15:13:00 schrieb Chris Mason:
> > On Mon, Oct 05, 2009 at 02:40:49PM +0200, Johannes Hirte wrote:
> > > I''m using btrfs on two devices here, /usr on sda3 and
/home on sdb
> > > (dm-crypt device on the whole disk). With btrfs-master the whole
system
> > > hangs when accessing /home. The system hangs when I''m
logging in into my
> > > account with KDE and is easily reproducible with dbench. On /usr
the
> > > hangs appeared also but not as often as on the /home-device.
I''ve tested
> > > on a third device with new created btrfs on top of dm-crypt, but
wasn''t
> > > able to reproduce the hangs. The filesystems are created without
> > > metadata-mirroring (-m single). I''ve bisected this to:
> > >
> > > commit 11833d66be94b514652466802100378046c16b72
> > > Author: Yan Zheng <zheng.yan@oracle.com>
> > > Date: Fri Sep 11 16:11:19 2009 -0400
> > >
> > > Btrfs: improve async block group caching
> >
> > Hello,
> >
> > Could you please capture the output of sysrq-l and sysrq-t during the
> > hang?
> >
> > -chris
> >
>
> sysrq-p shows:
>
> SysRq : Show Regs
> CPU 0:
> Modules linked in: netconsole snd_seq_midi snd_emu10k1_synth snd_emux_synth
> snd_seq_virmidi snd_seq_midi_emul snd_seq_oss snd_seq_midi_event snd_seq
> snd_pcm_oss snd_mixer_oss btrfs zlib_deflate crc32c libcrc32c aes_x86_64
> aes_generic xts gf128mul dm_crypt snd_emu10k1 snd_rawmidi snd_ac97_codec
> ac97_bus snd_pcm snd_seq_device snd_timer snd_page_alloc snd_util_mem
> snd_hwdep snd sg sr_mod ehci_hcd uhci_hcd ohci_hcd
> Pid: 2623, comm: dbench Not tainted 2.6.31-btrfs #3 To Be Filled By O.E.M.
> RIP: 0010:[<ffffffff811804b4>] [<ffffffff811804b4>]
find_next_zero_bit+0x1a/0xa0
Interesting, I''ve seen this as well, but haven''t yet tracked
it down to
a single commit. This means the allocator is probably looping as we try
to cache extents.
We''ll try to nail it down.
-chris
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