Re: Ceph on btrfs 3.4rc

[Sage Weil <sage@xxxxxxxxxxxx>]

On Tue, 24 Apr 2012, Josef Bacik wrote:
> On Fri, Apr 20, 2012 at 05:09:34PM +0200, Christian Brunner wrote:
> > After running ceph on XFS for some time, I decided to try btrfs again.
> > Performance with the current "for-linux-min" branch and big metadata
> > is much better. The only problem (?) I'm still seeing is a warning
> > that seems to occur from time to time:

Actually, before you do that... we have a new tool, 
test_filestore_workloadgen, that generates a ceph-osd-like workload on the 
local file system.  It's a subset of what a full OSD might do, but if 
we're lucky it will be sufficient to reproduce this issue.  Something like

 test_filestore_workloadgen --osd-data /foo --osd-journal /bar

will hopefully do the trick.

Christian, maybe you can see if that is able to trigger this warning?  
You'll need to pull it from the current master branch; it wasn't in the 
last release.

Thanks!
sage


> > 
> > [87703.784552] ------------[ cut here ]------------
> > [87703.789759] WARNING: at fs/btrfs/inode.c:2103
> > btrfs_orphan_commit_root+0xf6/0x100 [btrfs]()
> > [87703.799070] Hardware name: ProLiant DL180 G6
> > [87703.804024] Modules linked in: btrfs zlib_deflate libcrc32c xfs
> > exportfs sunrpc bonding ipv6 sg serio_raw pcspkr iTCO_wdt
> > iTCO_vendor_support i7core_edac edac_core ixgbe dca mdio
> > iomemory_vsl(PO) hpsa squashfs [last unloaded: scsi_wait_scan]
> > [87703.828166] Pid: 929, comm: kworker/1:2 Tainted: P           O
> > 3.3.2-1.fits.1.el6.x86_64 #1
> > [87703.837513] Call Trace:
> > [87703.840280]  [<ffffffff8104df6f>] warn_slowpath_common+0x7f/0xc0
> > [87703.847016]  [<ffffffff8104dfca>] warn_slowpath_null+0x1a/0x20
> > [87703.853533]  [<ffffffffa0355686>] btrfs_orphan_commit_root+0xf6/0x100 [btrfs]
> > [87703.861541]  [<ffffffffa0350a06>] commit_fs_roots+0xc6/0x1c0 [btrfs]
> > [87703.868674]  [<ffffffffa0351bcb>]
> > btrfs_commit_transaction+0x5db/0xa50 [btrfs]
> > [87703.876745]  [<ffffffff810127a3>] ? __switch_to+0x153/0x440
> > [87703.882966]  [<ffffffff81070a90>] ? wake_up_bit+0x40/0x40
> > [87703.888997]  [<ffffffffa0352040>] ?
> > btrfs_commit_transaction+0xa50/0xa50 [btrfs]
> > [87703.897271]  [<ffffffffa035205f>] do_async_commit+0x1f/0x30 [btrfs]
> > [87703.904262]  [<ffffffff81068949>] process_one_work+0x129/0x450
> > [87703.910777]  [<ffffffff8106b7eb>] worker_thread+0x17b/0x3c0
> > [87703.916991]  [<ffffffff8106b670>] ? manage_workers+0x220/0x220
> > [87703.923504]  [<ffffffff810703fe>] kthread+0x9e/0xb0
> > [87703.928952]  [<ffffffff8158c224>] kernel_thread_helper+0x4/0x10
> > [87703.935555]  [<ffffffff81070360>] ? kthread_freezable_should_stop+0x70/0x70
> > [87703.943323]  [<ffffffff8158c220>] ? gs_change+0x13/0x13
> > [87703.949149] ---[ end trace b8c31966cca731fa ]---
> > [91128.812399] ------------[ cut here ]------------
> > [91128.817576] WARNING: at fs/btrfs/inode.c:2103
> > btrfs_orphan_commit_root+0xf6/0x100 [btrfs]()
> > [91128.826930] Hardware name: ProLiant DL180 G6
> > [91128.831897] Modules linked in: btrfs zlib_deflate libcrc32c xfs
> > exportfs sunrpc bonding ipv6 sg serio_raw pcspkr iTCO_wdt
> > iTCO_vendor_support i7core_edac edac_core ixgbe dca mdio
> > iomemory_vsl(PO) hpsa squashfs [last unloaded: scsi_wait_scan]
> > [91128.856086] Pid: 6806, comm: btrfs-transacti Tainted: P        W  O
> > 3.3.2-1.fits.1.el6.x86_64 #1
> > [91128.865912] Call Trace:
> > [91128.868670]  [<ffffffff8104df6f>] warn_slowpath_common+0x7f/0xc0
> > [91128.875379]  [<ffffffff8104dfca>] warn_slowpath_null+0x1a/0x20
> > [91128.881900]  [<ffffffffa0355686>] btrfs_orphan_commit_root+0xf6/0x100 [btrfs]
> > [91128.889894]  [<ffffffffa0350a06>] commit_fs_roots+0xc6/0x1c0 [btrfs]
> > [91128.897019]  [<ffffffffa03a2b61>] ?
> > btrfs_run_delayed_items+0xf1/0x160 [btrfs]
> > [91128.905075]  [<ffffffffa0351bcb>]
> > btrfs_commit_transaction+0x5db/0xa50 [btrfs]
> > [91128.913156]  [<ffffffffa03524b2>] ? start_transaction+0x92/0x310 [btrfs]
> > [91128.920643]  [<ffffffff81070a90>] ? wake_up_bit+0x40/0x40
> > [91128.926667]  [<ffffffffa034cfcb>] transaction_kthread+0x26b/0x2e0 [btrfs]
> > [91128.934254]  [<ffffffffa034cd60>] ?
> > btrfs_destroy_marked_extents.clone.0+0x1f0/0x1f0 [btrfs]
> > [91128.943671]  [<ffffffffa034cd60>] ?
> > btrfs_destroy_marked_extents.clone.0+0x1f0/0x1f0 [btrfs]
> > [91128.953079]  [<ffffffff810703fe>] kthread+0x9e/0xb0
> > [91128.958532]  [<ffffffff8158c224>] kernel_thread_helper+0x4/0x10
> > [91128.965133]  [<ffffffff81070360>] ? kthread_freezable_should_stop+0x70/0x70
> > [91128.972913]  [<ffffffff8158c220>] ? gs_change+0x13/0x13
> > [91128.978826] ---[ end trace b8c31966cca731fb ]---
> > 
> > I'm able to reproduce this with ceph on a single server with 4 disks
> > (4 filesystems/osds) and a small test program based on librbd. It is
> > simply writing random bytes on a rbd volume (see attachment).
> > 
> > Is this something I should care about? Any hint's on solving this
> > would be appreciated.
> > 
> 
> Can you send me a config or some basic steps for me to setup ceph on my box so I
> can run this program and finally track down this problem?  Thanks,
> 
> Josef
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