so the only option for you is mount filesystem in recovery shell: Code: mount -o subvolid=0 /dev/mmcblk0p28 /mnt/ and try to Code: btrfs balance start /mnt/@ btrfs balance start /mnt/@home or manually delete something (check space before with btrfs fi show)
mount -o subvolid=0 /dev/mmcblk0p28 /mnt/
btrfs balance start /mnt/@ btrfs balance start /mnt/@home
/ # btrfs fi show Label: 'sailfish' uuid: 0f8a2490-53ed-4ff6-ba34-b81df3430387 Total devices 1 FS bytes used 6.46GB devid 1 size 13.75GB used 11.07GB path /dev/mmcblk0p28 Btrfs v0.20-rc1