mkfs.btrfs -L mylabel /dev/disk

    mount btrfs
    mount -t btrfs /dev/sda2 /mnt/btrfs

    btrfs subvolume create /mnt/btrfs/new_subvol
    btrfs subvolume snapshot /mnt/btrfs /mnt/btrfs/snapshot_of_root
    mount -t btrfs -o subvol=new_subvol /dev/sda2 /mnt/new_subvol mount -t btrfs -o subvol=snapshot_of_root /dev/sda2 /mnt/snap

    enable quota for subvolumes
    # btrfs subvolume list / | cut -d’ ‘ -f2 | xargs -I{} -n1 btrfs qgroup create 0/{} /

    show quota
    btrfs quota rescan /
    btrfs qgroup show /
    limit 1G for volume
    btrfs qgroup limit 1G /home/student3