If you ever wanted to resize a partition to grow unfilled space, you can use parted to grow the partition size.
Now note the size of the disk and the start of the partition that you want to resize.
Partition Type ? primary/extended ? primary Filesystem type? [ext2]? ext4 start ? startSizeMb/GB End? endSizeMb/GB quit reboot (may not be necessary) resize2fs /dev/sdx