We are not sure yet. Locke dreamed that the cabin was being build by Horace Goodspeed, Ben's dad. Later on Horace's body Locke finds the blue-prints and a map with it's location. When we first see the cabin Ben tells that Jacob is inside but he can't see him. But Locke hears someone speak, saying 'Help me'. The cabin at that time was surrounded by ash. In later episodes we see several people there. Including Christian and Claire. Also the ring of ash is broken. As we've learned on the show a circle of ash can stop the Smoke monster from harming you.
Anyway, the cabin got burned in the end.
Horace Goodspeed was Ethan Goodspeed's father. Ben's dad is Roger Linus.