Wondering the best way to add more disk space to /dev/mapper/system-root

Filesystem Type Size Used Avail Use% Mounted on
/dev/mapper/system-root btrfs 118G 107G 2.1G 99% /
udev tmpfs 1.9G 96K 1.9G 1% /dev
tmpfs tmpfs 1.9G 652K 1.9G 1% /dev/shm
/dev/sda1 ext3 152M 43M 101M 30% /boot

Added more space and configured as /dev/sda2

Disk /dev/sda: 214.7 GB, 214748364800 bytes
255 heads, 63 sectors/track, 26108 cylinders, total 419430400 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x000303c9

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 321535 159744 83 Linux
/dev/sda2 321536 419430399 209554432 83 Linux

Not sure how to make that space available to /dev/mapper/system-root
Followed this for adding sda2
https://www.suse.com/support/kb/doc/?id=7018329

Thanks!