Re: ENOSPC with 270GiB free

[Goswin von Brederlow <goswin-v-b@web.de>]

On Tue, Feb 18, 2014 at 08:58:10AM -0500, Josef Bacik wrote:
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> On 02/16/2014 08:58 AM, Goswin von Brederlow wrote:
> > Hi,
> > 
> > I'm getting a ENOSPC error from btrfs despite there still being
> > plenty of space left:
> > 
> > % df -m /mnt/nas3 Filesystem         1M-blocks     Used Available
> > Use% Mounted on /dev/mapper/nas3-a  19077220 18805132    270773
> > 99% /mnt/nas3
> > 
> > % btrfs fi show Label: none  uuid:
> > 4b18f84e-2499-41ca-81ff-fe1783c11491 Total devices 1 FS bytes used
> > 17.91TiB devid    1 size 18.19TiB used 17.94TiB path
> > /dev/mapper/nas3-a
> > 
> > Btrfs v3.12
> > 
> > % btrfs fi df Data, single: total=17.89TiB, used=17.88TiB System,
> > DUP: total=32.00MiB, used=1.92MiB Metadata, DUP: total=25.50GiB,
> > used=24.89GiB
> > 
> > As you can see there are still 270GiB free and plenty of block
> > groups free on the device too.
> > 
> > So why isn't btrfs allocating a new block group to store more
> > data?
> > 
> > 
> 
> What kernel?  Can you give btrfs-next a try?  Mount with -o
> enospc_debug and when you get enospc send the dmesg.  Thanks,
> 
> Josef

Standard Debian linux kernel:

Linux nas3 3.12-1-amd64 #1 SMP Debian 3.12.9-1 (2014-02-01) x86_64 GNU/Linux

Compiling new kernel and rebooting will take some time. But it looks
like I can remount with enospc_debug. I will try if that outputs
anything usefull first. So far I got:

[258988.006643] btrfs: disk space caching is enabled

MfG
	Goswin