[Matt R.]

I would actually min-raise here. I think it will shut villain down almost always if he does not have the flush and get you a cheap showdown. If he keeps coming at you, you can be very certain that he has the flush and you can get away from the hand with a weaker, but playable stack.

Calling will invite villain to bet the river again (probably for more than 150 -- the cost of a min-raise) even if he doesn't have the flush, and folding an overpair in a pot this size isn't a great option imo.