I guess I'm the nit here, but I hate playing for 400bb pots without a flush on a board that has 3 spades. If you get it all in here, you're behind more often than not even against a fish.

I missed that OP had a flush draw on the flop. Since he gave you perfect odds, I don't see anything wrong with the call as long as you're careful. You may not be giving all sorts of reverse implied odds, but you're working in reverse implied odds territory given his limp reraise and your lack of a draw to the nuts. The cards that make your hand could also give you an expensive second best.

In conclusion, I think OP played it good.