Merge pull request #2836 from ceph/wip-7317

#7317 ENOSPC and OSD epoch barrier handling

Reviewed-by: Yan, Zheng <zyan@redhat.com>
Reviewed-by: Greg Farnum <gfarnum@redhat.com>

diff --cc src/client/Client.cc
Simple merge

diff --cc src/common/config_opts.h
Simple merge

diff --cc src/mds/MDS.cc
Simple merge

diff --cc src/os/MemStore.cc
Simple merge

diff --cc src/os/MemStore.h
Simple merge

diff --cc src/osdc/Objecter.cc
Simple merge

diff --cc src/osdc/Objecter.h
Simple merge