Move a linux instalation using btrfs on the default subvolume (subvolid=0) to another subvolume

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http://unix.stackexchange.com – When doing a installation to a root btrfs filesystem, many linux distributions install to the default subvolume. If left unmodified, this layout will force any snapshots or subvolumes to be created inside the root filesystem, which may be undesirable. Another possible layout would be to have the default subvolume contain a snapshots directory, and a rootfs subvolume, which is the root filesystem. How can I change the distro-default btrfs installation to use this subvolume layout without booting from a livecd? (HowTos)