Geneva Firefighters (Ontario County) responded for a reported structure fire this morning. First arriving units reported a 2 1/2 with fire showing from the B side on the #2 floor. During operations interior reported a MAYDAY. A firefighter fell through the floor while attacking the main fire room. The crew was fortunate enough to hit the surrounding fire and pull the firefighter from the hole quickly. The fire was reported under control within 45 minutes with extensive overhaul.