To release a Genjutsu, Someone else has to place chakra into yours.
A Diffrent Source of Chakra has to be placed into the victim, canceling the Genjutsu. Or you can doit yourself by disrupting your own chakra which takes Time.
Pain cannot use his other bodies to free him from Genjustu, Because ALL of Pains Bodies have the Exact Same source of Chakra (Nagato)
SO it has to be a diffrent source, As Shown when the 30% itachi got NAruto in a regular Genjutsu, Even Naruto who has a LARGE Chakra reserve couldnt escape it even though he tried. And Not many people have More CHakra than Naruto. Sakura and Chiyo had to release him by placing their chakra into naruto. Or if you have an Tailed beast (Which is a DIFFRENT chakra source) they can release you.