Default low storage bug

i have a c2004 4.2.2 recently rooted xperia m

i cant install or update whatsapp/update chromme/install gl2sd

all of them says that i dont have enough memory,but i have over 600mb free(i installed and deleted many things and no luck)

i tried many versions of whatsapp and gl2sd too(from the playstore too)

plz help