I really don’t know what you were doing in the end,
because you don’t give that much information on that.
Just a guess:
openSUSE still uses legacy GRUB, which for booting from “/” can address only
root partitions that entirely (i.e. as a WHOLE) are below 128 GB.
Perhaps you should create a separate “/” (root) partition with a max size of 128 GB,
and a separate home partition thereafter.
To create two separate partitions for “/” (root) and “/home” would anyway be the best idea,
especially if the system should ever be updated to any future version
openSUSE 12.2, 12.3, 12.4, 13.1 …