Merge PR #28330 into master

Merge PR #28330 into master

* refs/pull/28330/head:
	osd: drop osd_lock during scrub
	ceph_test_rados_api_tier_pp: tolerate ENOENT or success from deleted snap
	osd: automatically scrub purged_snaps every deep scrub interval
	osd: move scrub_purged_snaps to helper
	osd/OSDMap: SERVER_OCTOPUS feature bit is now significant
	ceph_test_rados_api_snapshots_pp: drop unnecessary assert
	mon/OSDMonitor: record last_purged_snaps_scrub from beacon to osdmap
	osd: report last_purged_snaps_scrub as part of beacon
	osd: log purged_snaps scrub to cluster log
	osd: record last_purged_snaps_scrub in superblock
	osd/OSDMap: add last_purged_snaps_stamp to osd_xinfo_t
	mon/OSDMonitor: fix bug in try_prune_purged_snaps
	mon/OSDMonitor: record snap removal seq as purged
	mon/OSDMonitor: do not bother reporting gaps in removed_snaps
	osdc/Objecter: don't worry about gap_removed_snaps from map gaps
	mds/SnapServer: make not about pre-octopus compat code
	osd: implement scrub_purged_snaps command
	osd/PrimaryLogPG: always remove the snap we are trimming
	ceph_test_rados_api_snapshots_pp: (partial) test to reproduce stray clones
	osd: sync old purged_snaps on startup after upgrade or osd creation
	osd: record purged_snaps when we store new maps
	mon/OSDMonitor: add messages to get past purged_snaps
	mon/OSDMonitor: record pre-octopus purged snaps with first octopus map
	mon/OSDMonitor: record purged_snaps for each epoch
	mon/OSDMonitor: make_snap_epoch_key -> make_removed_snap_epoch_key
	osd/osd_types: add purged_snaps_last to OSDSuperblock
	osd/osd_types: clean up initial values for OSDSuperblock
	mon/OSDMonitor: make {removed,purged}_snap storage more efficient
	mon/OSDMonitor: move (removed, purged) snap update into a helper
	mon/OSDMonitor: generalize/refactor lookup_*_snap
	mon/OSDMonitor: refactor snap key and value helpers
	mon/OSDMonitor: make_snap_key -> make_removed_snap_key, make_purged_snap_key
	mon/OSDMonitor: fix lookup_purged_snap implementation
	mon/OSDMonitor: lookup_pruned_snap -> lookup_purged_snap
	osd: adjust snapmapper keys on first start as octopus
	osd/SnapMapper: include poolid in snap index
	mon/OSDMonitor: document osd snap metadata format
	osd/SnapMapper: document stored keys and values
	mon/OSDMonitor: use structured binding for prepare_remove_snaps
	mon/OSDMonitor: send MRemoveSnaps back to octopus MDS
	mds/SnapServer: handle MRemoveSnaps acks from mon
	CMakeLists: include 'cephfs' (which includes libcephfs) in 'vstart' target
	mon/PaxosService: add C_ReplyOp
	vnewosd.sh: add script to add a new osd to an existing vstart
	vstart.sh: remove useless auth add for osds
	vstart.sh: wait for mgr volume module to start up
	mon/OSDMonitor: make snap removal handle dups safely
	mon/OSDMonitor: only update removed_snaps when pre-octopus
	ceph_test_rados: stop doing long object names
	ceph_test_rados_api_tier_pp: fix osd version checks
	osd/PrimaryLogPG: use get_ssc_as_of for snapc for flushing clones
	osd/PrimaryLogPG: only maintain SnapSet::snaps for pre-octopus compat
	mon/OSDMonitor: only maintain pg_pool_t::removed_snaps for pre-octopus
	osd/osd_types: mark SnapSet::snaps as legacy
	osd/osd_types: SnapSet::get_ssc_as_of: use clone_snaps
	osd/PrimaryLogPG: change fabrication of promoted clone snaps
	osd/PrimaryLogPG: only filter SnapSet::snaps for flush for pre-octopus compat
	osd/PrimaryLogPG: trim_objects: only filter SnapSet::snaps for pre-octopus
	osd/PrimaryLogPG: make best effort to sanitize clones on copy-from
	mds/SnapServer: int -> int32_t for encoded type
	messages/MRemoveSnaps: int -> int32_t on encoded type
	osd/PrimaryLogPG: find_object_context: trust SnapSet's clone_snaps
	osd/PrimaryLogPG: use osdmap removed_snaps_queue for snap trimming
	mon/OSDMonitor: avoid is_removed_snap()
	osd/PeeringState: drop some mimic conditionals
	osd/PG: drop pre-mimic snap_trimq code
	osd/PeeringState: removed pre-mimic removed snap tracking
	osd: move snap_interval_set_t to osd_types
	mon: drop mon_debug_no_require_mimic
	mon/OSDMonitor: remove pre-mimic snap behavior support
	mon/OSDMonitor: remove support for pre-mimic conversion
	osd/osd_types: remove build_removed_snaps(), maybe_update_removed_snaps()
	osd: remove luminous compat code for removed_snaps

Reviewed-by: Samuel Just <sjust@redhat.com>
Reviewed-by: Neha Ojha <nojha@redhat.com>