When I installed this machine, it was on a 120gb SSD. Now I've moved it over to a 256gb SSD and am wasting a ton of space:
# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
sda 8:0 0 223.6G 0 disk
├─sda1 8:1 0 512M 0 part /boot/efi
├─sda2 8:2 0 488M 0 part /boot
└─sda3 8:3 0 118.3G 0 part
├─alonso--vg-root 252:0 0 86.3G 0 lvm /
└─alonso--vg-swap_1 252:1 0 32G 0 lvm [SWAP]
How can I actually expand sda3 and then lvextend root to take advantage of the new space without just wiping out the disk and starting over?