Comment 11 for bug 1765998

Recently hit that on Focal due to the fact that quotas were enabled by LXD.

This renders the system completely unresponsive if you use btrfs as a rootfs with btrfs-transaction or btrfs-cleaner kernel threads hogging a 100% of 1 CPU core.

Booting using a live USB, disabling quotas and temporarily moving /etc/systemd/system/snap-lxd-* files out helps (followed by `snap disable lxd` until it gets updated with https://github.com/lxc/lxd/pull/7032).