If the room is only 2M x 2M then you won't have much room to use an upright
drum sander, the handles stick out a fair way. If it's that small then an
edging sander may do it easily enough.

I did a few floors with a drum sander and scrimped on the hire for an edge
sander using my own belt sander instead, then a hire company would only hire
me the two together and I found the edger quite a powerful little beasty
saving a huge amount of time. Being rotary though the finish is not as good
as the drum sander.

Henry