resize2fs complains it has nothing to do because it only works at system size. First you have to grow the partition size underneath it with fdisk, cfdisk or parted. 

https://geekpeek.net/resize-filesystem-fdisk-resize2fs/

Similar with LVM, it needs more free partition space to grow, or a new partition added to the LVM volume group.

https://www.turnkeylinux.org/blog/extending-lvm