Hi Josef and Jens, this series tries to deal with the fallout of the recent lock scope reduction as pointed out by Tetsuo and szybot and inspired by / reused from the catchall patch by Tetsuo. One big change is that I finally decided to kill off the ->destroy_complete scheme entirely because I'm pretty sure it is not needed with the various fixes and we can just return an error for the tiny race condition where it matters. Xiubo, can you double check this with your nbd-runner setup? nbd-runner itself seems pretty generic and not directly reproduce anything here. Note that the syzbot reproduer still fails eventually, but in devtmpfsd in a way that does not look related to the loop code at all.
