[5e] [Paladin] [Great Weapon Fighting] PHB says:

"When you roll a 1 or 2 on a damage die for an attack you make with a melee weapon that you are wielding with two hands, you can reroll the die and must use the new roll. The weapon must have the two-handed or versatile property for you to gain this benefit." Does the ability to reroll apply to Critical Dice? For example, with my Greatsword the damage is 2d6 + Str mod Slashing; If I get a critical hit, I would roll 4d6 +Str mod, and could I reroll any 1 or 2 and take the new roll?

Also, if I use my Divine Smite does the Great Weapon Fighting feature apply to the damage roll for the Divine Smite (2d8)?