So apparently what happened was after rooting somehow, my sd card got totaled. By totaled I mean that it became read only. So I could still get my previous data from the card, but couldn't write new data on it. Whenever you write some data using your phone/pc on the card, at first it shows that it is written (i.e: the file is pasted or etc), but as soon as you refresh the file explorer , you see all write actions were rolled back. I simply copied the important data, and replaced the sd card with a new one.