How do I prevent someone spamming a Linux public folder?

Question

I recently created a Public folder for my user on samba. I have it set up so that anyone can access it on my network(it's just me and a couple other computers). How do I prevent the other computers from dumping huge amounts of data into that folder, and thus exceeding the amount of space the drive holds. e.g. Someone dumps 200GB of garbled text onto a 50GB drive. I guess what I am asking is "how to limit a folders capacity?".