I am sorry to hear you have come across this bug, we apologise that this has happened.
I had a look into this bug for you, it is indeed one that Bethesda are aware of, and it will probably be fixed in future updates, for now, though, here's the information I found about bypassing the bug.
It would seem completing the College of Winterhold storyline before this quest will break it, Urag gro-Shub, the librarian will not have the needed dialogue options to continue the quest.
"PC users can use the console to progress the quest by setting its stage to 80, this will let you play through the rest of the quest and finish it properly."
"It might also be possible to bypass this bug simply by going to the Dwemer Ruin the quest would normally lead you to, and play through it as normal, without first progressing the quest to the proper stage. You will however, of course, not have any objective markers to rely on."
I hope some of this helps you, and that you are able to continue on with the game, and enjoy it as intended.
Kind Regards,
Francesca, Bethesda Technical Support
Drem. Patience.There are formalities that must be observed, at the first meeting of two of the dov. By long tradition, the elder speaks first. Hear my Thu'um! Feel it in your bones. Match it, if you are Dovahkiin!