Bug in fua code

Ming, I recently discovered a bug in the FUA code - a recent bcachefs change exposed it - and my best guess is it's related to your recent changes to blk-flush.c. What I'm seeing is if all writes are issued as FUA writes, in a short period of time the request queue get stuck - writes

Bug in fua code

Ming, I recently discovered a bug in the FUA code - a recent bcachefs change exposed it - and my best guess is it's related to your recent changes to blk-flush.c. What I'm seeing is if all writes are issued as FUA writes, in a short period of time the request queue get stuck - writes