Merge PR #16779 into master

* refs/pull/16779/head:
	mds: cleanup MDCache::open_snaprealms()
	mds: make sure snaptable version > 0
	mds: don't consider CEPH_INO_LOST_AND_FOUND as base inode
	mds: replace MAX() with std::max()
	tools/cephfs: make cephfs-data-scan create snaprealm for base inodes
	qa/cephfs: don't run TestSnapshots.test_kill_mdstable on kclient
	qa/cephfs: adjust check of 'cephfs-table-tool all show snap' output
	mds: don't warn unconnected snaplrealms in cluster log
	mds: update CInode/CDentry's first according to global snapshot seq
	qa/cephfs: add tests for snapclient cache
	qa/cephfs: add tests for snaptable transaction
	mds: add asok command that dumps cached snap infos
	qa/cephfs: add tests for multimds snapshot
	client: don't mark snap directory complete when its dirstat is empty
	qa/workunits/snaps: add snaprealm split test
	mds: make sure mds has uptodate mdsmap before checking 'allows_snaps'
	client: fix incorrect snaprealm when adding caps
	qa/workunits/snaps: add hardlink snapshot test
	mds: add incompat feature and bump protocol for snapshot changes
	mds: detach inode with single hardlink from global snaprealm
	mds: record hardlink snaps in inode's snaprealm
	mds: attach inode with multiple hardlinks to dummy global snaprealm
	mds: cleanup rename code
	mds: ensure xlocker has uptodate lock state
	mds: simplify SnapRealm::build_snap_{set,trace}
	mds: record global last_created/last_destroyed in snaptable
	mds: pop projected snaprealm before inode's parent changes
	mds: keep isnap lock in sync state
	mds: handle mksnap vs resolve_snapname race
	mds: cleanup snaprealm past parents open check
	mds: rollback snaprealms when rolling back slave request
	mds: send updated snaprealms along with slave requests
	mds: explict notification for snap update
	mds: send snap related messages centrally during mds recovery
	mds: synchronize snaptable caches when mds recovers
	mds: introduce MDCache::maybe_finish_slave_resolve()
	mds: notify all mds about prepared snaptable update
	mds: record snaps in old snaprealm when moving inode into new snaprealm
	mds: cache snaptable in snapclient
	mds: recover snaptable client when mds enters resolve state

Reviewed-by: Patrick Donnelly <pdonnell@redhat.com>

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

diff --cc src/include/ceph_fs.h
Simple merge

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

diff --cc src/mds/CInode.h
Simple merge

diff --cc src/mds/CMakeLists.txt
Simple merge

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

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

diff --cc src/mds/MDCache.h
Simple merge

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

diff --cc src/mds/MDSDaemon.h
Simple merge

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

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

diff --cc src/mds/Server.cc
index d2c29d8ebd08a3dec6183e7eadc6084f90dd125d,56276f663c04979165d136afa29d2be9c09dc699..2fdc623855a825208b1f3352071106fa7b93c55d
--- 1/src/mds/Server.cc
--- 2/src/mds/Server.cc
+++ b/src/mds/Server.cc
@@@ -3663,8 -3655,10 +3681,8 @@@ void Server::handle_client_openc(MDRequ
  
    // make sure this inode gets into the journal
    le->metablob.add_opened_ino(in->ino());
 -  LogSegment *ls = mds->mdlog->get_current_segment();
 -  ls->open_files.push_back(&in->item_open_file);
  
-   C_MDS_openc_finish *fin = new C_MDS_openc_finish(this, mdr, dn, in, follows);
+   C_MDS_openc_finish *fin = new C_MDS_openc_finish(this, mdr, dn, in);
  
    if (mdr->client_request->get_connection()->has_feature(CEPH_FEATURE_REPLY_CREATE_INODE)) {
      dout(10) << "adding ino to reply to indicate inode was created" << dendl;

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

diff --cc src/msg/Message.cc
Simple merge

diff --cc src/msg/Message.h
Simple merge

diff --cc src/tools/cephfs/DataScan.cc
Simple merge