Just like what Wang has mentioned, would you please paste all the output 
of the contents of /sys/fs/btrfs/<your fs uuid>/allocation?

It's recommended to use "grep . -IR <path>" to get all the data as it 
will show the file name.

Thanks,
Qu

At 09/03/2016 03:25 AM, Ronan Arraes Jardim Chagas wrote:

Hi guys!

Jeff was right. I had the problem again today and quotas are disabled
now. I couldn't get any useful message in log this time. Look at the
metadata:

btrfs fi usage /
Overall:
    Device size:		   1.26TiB
    Device allocated:		  43.07GiB
    Device unallocated:		   1.21TiB
    Device missing:		     0.00B
    Used:			  41.94GiB
    Free (estimated):		   1.21TiB	(min: 622.46GiB)
    Data ratio:			      1.00
    Metadata ratio:		      2.00
    Global reserve:		 352.00MiB	(used: 0.00B)

Data,single: Size:40.01GiB, Used:39.94GiB
   /dev/sda6	  40.01GiB

Metadata,DUP: Size:1.50GiB, Used:1.00GiB
   /dev/sda6	   3.00GiB

System,DUP: Size:32.00MiB, Used:16.00KiB
   /dev/sda6	  64.00MiB

Unallocated:
   /dev/sda6	   1.21TiB

Any ideas to help me?

Regards,
Ronan Arraes