Translations:Btrfs/33/en
To have access to the root(/) of your volume, you need to mount this separately. (Please do not confuse this with "/" of the file system)
root # mount -t btrfs -o subvol=/,defaults [/dev/sdz2] /mnt
Now you are able to create a new subvolume in a flat layout.
root # btrfs subvolume create [/mnt/@tests]
This will be shown by
root # ls -l /mnt
root # btrfs subvolume list /mnt
This subvolume tests is empty. And it is not mounted by default. So if you want to use it, you have to mount it by fstab or other means. Now lets delete it again.
root # btrfs subvolume delete [/mnt/@tests]
root # umount /mnt