After SERVER-53118 any operation waiting for a dist lock will wait for 20 seconds before returning a LockBusy error if couldn't acquire the lock. Additionally, notify all is being used when unlocking to wake up all waiting operations. If we have too many concurrent operations and they're taking too long, these two facts might end up starving a request. We should preserve the acquisition order using notify_one, and increase the timeout (for example to two hours).