0/257 817819648 4096
0/258 38080512 4096
0/259 4096 4096
0/264 817819648 4096
0/265 38080512 4096
[root@localhost nemo]#
mount -o subvolid=0 /dev/mmcblk0p28 /mnt/

[root@localhost nemo]# ls -la /mnt/
total 4
drwxr-xr-x 1 root root 260 Feb 9 13:40 .
drwxr-xr-x 1 root root 718 Feb 14 11:03 ..
drwxr-xr-x 1 root root 718 Feb 14 11:03 @
drwxr-xr-x 1 root root 768 Feb 8 13:42 @_old
drwxr-xr-x 1 root root 8 Nov 20 04:55 @home
drwxr-xr-x 1 root root 0 Nov 20 04:49 @swap
drwxr-xr-x 1 root root 610 Nov 20 04:55 factory-@
drwxr-xr-x 1 root root 8 Nov 20 04:55 factory-@home
drwxr-xr-x 1 root root 766 Feb 8 21:50 rec-20140209_093232_@
drwxr-xr-x 1 root root 8 Nov 20 04:55 rec-20140209_093232_@home
drwxr-xr-x 1 root root 754 Feb 9 13:36 rec-20140209_094009_@
drwxr-xr-x 1 root root 8 Nov 20 04:55 rec-20140209_094009_@home
[root@localhost nemo]#

[root@localhost nemo]# btrfs subvolume delete /mnt/rec-20140209_093232_@
Delete subvolume '/mnt/rec-20140209_093232_@'
ERROR: cannot delete '/mnt/rec-20140209_093232_@' - Directory not empty
[root@localhost nemo]#