I did this on my old Sirrus and just a word of caution---the top tube length was fine for flat bars but it turned out to be too long for good position on drops. Hurt my back going up a hill and ended up buying a properly fitting road bike anyway. So just do make sure you check out the change in posture to make sure it'll work for you.
"My predominant feeling is one of gratitude. I have loved and been loved;I have been given much and I have given something in return...Above all, I have been a sentient being, a thinking animal, on this beautiful planet, and that in itself has been an enormous privilege and an adventure." O. Sacks