I resized my LVM LV with lvextend -L +32G -r root because lvextend -r doesn’t work with btrfs apparently. This seems to have worked because I got Size of logical volume desktop/root changed from 32,00 GiB (8192 extents) to 64,00 GiB (16384 extents). and lvdisplay shows the correct size (64GiB).

Then I did btrfs filesystem resize max / which told me Resize device id 1 (/dev/mapper/root) from 31.98GiB to max – it’s still 32GB when I do findmnt -sD or btrfs fi sh / though.

What am I doing wrong?