# Must be done as root
echo 1 > /sys/class/block/sda/device/rescan

# For LVM
fdisk /dev/sda # For the resizing - delete it, then recreate it.
pvresize /dev/sda3
lvextend -l +100%FREE /dev/mapper/ubuntu--vg-ubuntu--lv
resize2fs /dev/mapper/ubuntu--vg-ubuntu--lv