add subvolume when / is not mounted?

Hi,

Well, I do not know if here is the right place to ask questions like this one so please tell me if it is not.
The situation is the following: btrfs (data and metadata single) on /dev/sda3 (size 100GB) with two subvolumes /one and /two. Both subvolumes are mounted to /mnt/one resp. /mnt/two. Is there a way to create a third subvolume, say three outside of the two existing subvolumes without mounting "the whole volume /dev/sda3" or even worse unmounting the two subvolumes before?

Thanks,
Andreas

At the moment no, you have to mount the default volume, or as you say "the whole volume /dev/sda3", and then create the new subvolume three. Thanks,

Josef