Merge remote-tracking branches 'upstream/master', 'upstream/wip-6756', 'upstream/wip-9031-9262', 'upstream/wip-9852', 'upstream/wip-9887', 'upstream/wip-9986', 'upstream/wip-9987', 'upstream/wip-aio-journal', 'upstream/wip-log-client', 'upstream/wip-warn-max-pg' and 'yuandong1222/avoid-unused-pg_to_acting_osds-call' into wip-sam-testing