Ceph » CephFS

There still has a risk client will hang all the time and which happened in my enviroment
a few days ago. Well konw, the start of mds will go through four stages at least(replay,
reconnect, rejoin, active). According to current logic, we recived replay mdsmap and
marked down pipe will return directly and if we miss the next reconnect mdsmap the client
may hang all the time becuase we lost the opportunity due to old_inc equal tonew_inc.
So we shuold judge if we have lost MDSMap::reconnect by comparing newstate and oldstate.