[PATCH 0/2] fix double completion of timed out commands

[Josef Bacik <josef@toxicpanda.com>]

We noticed a problem where NBD sometimes double completes the same request when
things go wrong and we time out the request.  If the other side goes out to
lunch but happens to reply just as we're timing out the requests we can end up
with a double completion on the request.

We already keep track of the command status, we just need to make sure we
protect all cases where we set cmd->status with the cmd->lock, which is patch
#1.  Patch #2 is the fix for the problem, which catches the case where we race
with the timeout handler and the reply handler.  Thanks,

Josef