If you're still playing Xbox 360 games through your Xbox One, you're going to have to take a break from them by force tomorrow as Microsoft will be instituting maintenance on backwards compatibility services tomorrow.
The maintenance will kick off around 4 a.m. EST (1 a.m PST) on April 27 and will go for roughly two hours. If you are playing a 360 game before it launches, you will be kicked off the server and may get disconnected from Xbox Live. You will not be able to play any 360 games online until it returns, nor will you be able to plug your 360 back in and play on the older console. Just take a break from the game, get a sandwich and read something, it'll be back before you know it.