btrfs filesystem df btrfs filesystem show btrfs filesystem defragment /path btrfs filesystem label /path <label>
btrfs subvolume create <name> btrfs subvolume show /path/to/subvolume btrfs subvolume list /path btrfs subvolume snapshot /old /new btrfs sub snap -r /old /.snapshot/ro # read only
btrfs subv set-default 258 /path mount -o subvol=/subv/0/vol0 /dev/sdb1 /path