// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*- 
	// vim: ts=8 sw=2 smarttab
	/*
	 * Ceph - scalable distributed file system
	 *
	 * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
	 *
	 * This is free software; you can redistribute it and/or
	 * modify it under the terms of the GNU Lesser General Public
	 * License version 2.1, as published by the Free Software 
	 * Foundation.  See file COPYING.
	 * 
	 */
	
	#include "common/debug.h"
	#include "mon/health_check.h"
	
	#include "MDSMap.h"
	
	#include <sstream>
	using std::stringstream;
	
	#define dout_context g_ceph_context
	#define dout_subsys ceph_subsys_
	
	// features
	CompatSet MDSMap::get_compat_set_all() {
	  CompatSet::FeatureSet feature_compat;
	  CompatSet::FeatureSet feature_ro_compat;
	  CompatSet::FeatureSet feature_incompat;
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_BASE);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_CLIENTRANGES);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_FILELAYOUT);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_DIRINODE);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_ENCODING);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_OMAPDIRFRAG);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_INLINE);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_NOANCHOR);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_FILE_LAYOUT_V2);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_SNAPREALM_V2);
	
	  return CompatSet(feature_compat, feature_ro_compat, feature_incompat);
	}
	
	CompatSet MDSMap::get_compat_set_default() {
	  CompatSet::FeatureSet feature_compat;
	  CompatSet::FeatureSet feature_ro_compat;
	  CompatSet::FeatureSet feature_incompat;
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_BASE);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_CLIENTRANGES);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_FILELAYOUT);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_DIRINODE);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_ENCODING);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_OMAPDIRFRAG);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_NOANCHOR);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_FILE_LAYOUT_V2);
	  feature_incompat.insert(MDS_FEATURE_INCOMPAT_SNAPREALM_V2);
	
	  return CompatSet(feature_compat, feature_ro_compat, feature_incompat);
	}
	
	// base (pre v0.20)
	CompatSet MDSMap::get_compat_set_base() {
	  CompatSet::FeatureSet feature_compat_base;
	  CompatSet::FeatureSet feature_incompat_base;
	  feature_incompat_base.insert(MDS_FEATURE_INCOMPAT_BASE);
	  CompatSet::FeatureSet feature_ro_compat_base;
	
	  return CompatSet(feature_compat_base, feature_ro_compat_base, feature_incompat_base);
	}
	
	void MDSMap::mds_info_t::dump(Formatter *f) const
	{
	  f->dump_unsigned("gid", global_id);
	  f->dump_string("name", name);
	  f->dump_int("rank", rank);
	  f->dump_int("incarnation", inc);
	  f->dump_stream("state") << ceph_mds_state_name(state);
	  f->dump_int("state_seq", state_seq);
	  f->dump_stream("addr") << addrs.get_legacy_str();
	  f->dump_object("addrs", addrs);
	  if (laggy_since != utime_t())
	    f->dump_stream("laggy_since") << laggy_since;
	  
	  f->open_array_section("export_targets");
	  for (set<mds_rank_t>::iterator p = export_targets.begin();
	       p != export_targets.end(); ++p) {
	    f->dump_int("mds", *p);
	  }
	  f->close_section();
	  f->dump_unsigned("features", mds_features);
	  f->dump_unsigned("flags", flags);
	}
	
	void MDSMap::mds_info_t::print_summary(ostream &out) const
	{
	  out << global_id << ":\t"
	      << addrs
	      << " '" << name << "'"
	      << " mds." << rank
	      << "." << inc
	      << " " << ceph_mds_state_name(state)
	      << " seq " << state_seq;
	  if (laggy()) {
	    out << " laggy since " << laggy_since;
	  }
	  if (!export_targets.empty()) {
	    out << " export_targets=" << export_targets;
	  }
	  if (is_frozen()) {
	    out << " frozen";
	  }
	}
	
	void MDSMap::mds_info_t::generate_test_instances(std::list<mds_info_t*>& ls)
	{
	  mds_info_t *sample = new mds_info_t();
	  ls.push_back(sample);
	  sample = new mds_info_t();
	  sample->global_id = 1;
	  sample->name = "test_instance";
	  sample->rank = 0;
	  ls.push_back(sample);
	}
	
	void MDSMap::dump(Formatter *f) const
	{
	  f->dump_int("epoch", epoch);
	  f->dump_unsigned("flags", flags);
	  f->dump_unsigned("ever_allowed_features", ever_allowed_features);
	  f->dump_unsigned("explicitly_allowed_features", explicitly_allowed_features);
	  f->dump_stream("created") << created;
	  f->dump_stream("modified") << modified;
	  f->dump_int("tableserver", tableserver);
	  f->dump_int("root", root);
	  f->dump_int("session_timeout", session_timeout);
	  f->dump_int("session_autoclose", session_autoclose);
	  f->dump_stream("min_compat_client") << ceph::to_integer<int>(min_compat_client) << " ("
					      << min_compat_client << ")";
	  f->dump_int("max_file_size", max_file_size);
	  f->dump_int("last_failure", last_failure);
	  f->dump_int("last_failure_osd_epoch", last_failure_osd_epoch);
	  f->open_object_section("compat");
	  compat.dump(f);
	  f->close_section();
	  f->dump_int("max_mds", max_mds);
	  f->open_array_section("in");
	  for (set<mds_rank_t>::const_iterator p = in.begin(); p != in.end(); ++p)
	    f->dump_int("mds", *p);
	  f->close_section();
	  f->open_object_section("up");
	  for (map<mds_rank_t,mds_gid_t>::const_iterator p = up.begin(); p != up.end(); ++p) {
	    char s[14];
	    sprintf(s, "mds_%d", int(p->first));
	    f->dump_int(s, p->second);
	  }
	  f->close_section();
	  f->open_array_section("failed");
	  for (set<mds_rank_t>::const_iterator p = failed.begin(); p != failed.end(); ++p)
	    f->dump_int("mds", *p);
	  f->close_section();
	  f->open_array_section("damaged");
	  for (set<mds_rank_t>::const_iterator p = damaged.begin(); p != damaged.end(); ++p)
	    f->dump_int("mds", *p);
	  f->close_section();
	  f->open_array_section("stopped");
	  for (set<mds_rank_t>::const_iterator p = stopped.begin(); p != stopped.end(); ++p)
	    f->dump_int("mds", *p);
	  f->close_section();
	  f->open_object_section("info");
	  for (map<mds_gid_t,mds_info_t>::const_iterator p = mds_info.begin(); p != mds_info.end(); ++p) {
	    char s[25]; // 'gid_' + len(str(ULLONG_MAX)) + '\0'
	    sprintf(s, "gid_%llu", (long long unsigned)p->first);
	    f->open_object_section(s);
	    p->second.dump(f);
	    f->close_section();
	  }
	  f->close_section();
	  f->open_array_section("data_pools");
	  for (const auto p: data_pools)
	    f->dump_int("pool", p);
	  f->close_section();
	  f->dump_int("metadata_pool", metadata_pool);
	  f->dump_bool("enabled", enabled);
	  f->dump_string("fs_name", fs_name);
	  f->dump_string("balancer", balancer);
	  f->dump_int("standby_count_wanted", std::max(0, standby_count_wanted));
	}
	
	void MDSMap::generate_test_instances(std::list<MDSMap*>& ls)
	{
	  MDSMap *m = new MDSMap();
	  m->max_mds = 1;
	  m->data_pools.push_back(0);
	  m->metadata_pool = 1;
	  m->cas_pool = 2;
	  m->compat = get_compat_set_all();
	
	  // these aren't the defaults, just in case anybody gets confused
	  m->session_timeout = 61;
	  m->session_autoclose = 301;
	  m->max_file_size = 1<<24;
	  ls.push_back(m);
	}
	
	void MDSMap::print(ostream& out) const
	{
	  out << "fs_name\t" << fs_name << "\n";
	  out << "epoch\t" << epoch << "\n";
	  out << "flags\t" << hex << flags << dec << "\n";
	  out << "created\t" << created << "\n";
	  out << "modified\t" << modified << "\n";
	  out << "tableserver\t" << tableserver << "\n";
	  out << "root\t" << root << "\n";
	  out << "session_timeout\t" << session_timeout << "\n"
	      << "session_autoclose\t" << session_autoclose << "\n";
	  out << "max_file_size\t" << max_file_size << "\n";
	  out << "min_compat_client\t" << ceph::to_integer<int>(min_compat_client) << " ("
				       << min_compat_client << ")\n";
	  out << "last_failure\t" << last_failure << "\n"
	      << "last_failure_osd_epoch\t" << last_failure_osd_epoch << "\n";
	  out << "compat\t" << compat << "\n";
	  out << "max_mds\t" << max_mds << "\n";
	  out << "in\t" << in << "\n"
	      << "up\t" << up << "\n"
	      << "failed\t" << failed << "\n"
	      << "damaged\t" << damaged << "\n"
	      << "stopped\t" << stopped << "\n";
	  out << "data_pools\t" << data_pools << "\n";
	  out << "metadata_pool\t" << metadata_pool << "\n";
	  out << "inline_data\t" << (inline_data_enabled ? "enabled" : "disabled") << "\n";
	  out << "balancer\t" << balancer << "\n";
	  out << "standby_count_wanted\t" << std::max(0, standby_count_wanted) << "\n";
	
	  multimap< pair<mds_rank_t, unsigned>, mds_gid_t > foo;
	  for (const auto &p : mds_info) {
	    foo.insert(std::make_pair(
	          std::make_pair(p.second.rank, p.second.inc-1), p.first));
	  }
	
	  for (const auto &p : foo) {
	    const mds_info_t& info = mds_info.at(p.second);
	    info.print_summary(out);
	    out << "\n";
	  }
	}
	
	
	
	void MDSMap::print_summary(Formatter *f, ostream *out) const
	{
	  map<mds_rank_t,string> by_rank;
	  map<string,int> by_state;
	
	  if (f) {
	    f->dump_unsigned("epoch", get_epoch());
	    f->dump_unsigned("up", up.size());
	    f->dump_unsigned("in", in.size());
	    f->dump_unsigned("max", max_mds);
	  } else {
	    *out << "e" << get_epoch() << ": " << up.size() << "/" << in.size() << "/" << max_mds << " up";
	  }
	
	  if (f)
	    f->open_array_section("by_rank");
	  for (const auto &p : mds_info) {
	    string s = ceph_mds_state_name(p.second.state);
	    if (p.second.laggy())
	      s += "(laggy or crashed)";
	
	    if (p.second.rank >= 0 && p.second.state != MDSMap::STATE_STANDBY_REPLAY) {
	      if (f) {
		f->open_object_section("mds");
		f->dump_unsigned("rank", p.second.rank);
		f->dump_string("name", p.second.name);
		f->dump_string("status", s);
		f->close_section();
	      } else {
		by_rank[p.second.rank] = p.second.name + "=" + s;
	      }
	    } else {
	      by_state[s]++;
	    }
	  }
	  if (f) {
	    f->close_section();
	  } else {
	    if (!by_rank.empty())
	      *out << " " << by_rank;
	  }
	
	  for (map<string,int>::reverse_iterator p = by_state.rbegin(); p != by_state.rend(); ++p) {
	    if (f) {
	      f->dump_unsigned(p->first.c_str(), p->second);
	    } else {
	      *out << ", " << p->second << " " << p->first;
	    }
	  }
	
	  if (!failed.empty()) {
	    if (f) {
	      f->dump_unsigned("failed", failed.size());
	    } else {
	      *out << ", " << failed.size() << " failed";
	    }
	  }
	
	  if (!damaged.empty()) {
	    if (f) {
	      f->dump_unsigned("damaged", damaged.size());
	    } else {
	      *out << ", " << damaged.size() << " damaged";
	    }
	  }
	  //if (stopped.size())
	  //out << ", " << stopped.size() << " stopped";
	}
	
	void MDSMap::get_health(list<pair<health_status_t,string> >& summary,
				list<pair<health_status_t,string> > *detail) const
	{
	  if (!failed.empty()) {
	    std::ostringstream oss;
	    oss << "mds rank"
		<< ((failed.size() > 1) ? "s ":" ")
		<< failed
		<< ((failed.size() > 1) ? " have":" has")
		<< " failed";
	    summary.push_back(make_pair(HEALTH_ERR, oss.str()));
	    if (detail) {
	      for (set<mds_rank_t>::const_iterator p = failed.begin(); p != failed.end(); ++p) {
		std::ostringstream oss;
		oss << "mds." << *p << " has failed";
		detail->push_back(make_pair(HEALTH_ERR, oss.str()));
	      }
	    }
	  }
	
	  if (!damaged.empty()) {
	    std::ostringstream oss;
	    oss << "mds rank"
		<< ((damaged.size() > 1) ? "s ":" ")
		<< damaged
		<< ((damaged.size() > 1) ? " are":" is")
		<< " damaged";
	    summary.push_back(make_pair(HEALTH_ERR, oss.str()));
	    if (detail) {
	      for (set<mds_rank_t>::const_iterator p = damaged.begin(); p != damaged.end(); ++p) {
		std::ostringstream oss;
		oss << "mds." << *p << " is damaged";
		detail->push_back(make_pair(HEALTH_ERR, oss.str()));
	      }
	    }
	  }
	
	  if (is_degraded()) {
	    summary.push_back(make_pair(HEALTH_WARN, "mds cluster is degraded"));
	    if (detail) {
	      detail->push_back(make_pair(HEALTH_WARN, "mds cluster is degraded"));
	      for (mds_rank_t i = mds_rank_t(0); i< get_max_mds(); i++) {
		if (!is_up(i))
		  continue;
		mds_gid_t gid = up.find(i)->second;
		map<mds_gid_t,mds_info_t>::const_iterator info = mds_info.find(gid);
		stringstream ss;
		if (is_resolve(i))
		  ss << "mds." << info->second.name << " at " << info->second.addrs
		     << " rank " << i << " is resolving";
		if (is_replay(i))
		  ss << "mds." << info->second.name << " at " << info->second.addrs
		     << " rank " << i << " is replaying journal";
		if (is_rejoin(i))
		  ss << "mds." << info->second.name << " at " << info->second.addrs
		     << " rank " << i << " is rejoining";
		if (is_reconnect(i))
		  ss << "mds." << info->second.name << " at " << info->second.addrs
		     << " rank " << i << " is reconnecting to clients";
		if (ss.str().length())
		  detail->push_back(make_pair(HEALTH_WARN, ss.str()));
	      }
	    }
	  }
	
	  {
	  stringstream ss;
	  ss << fs_name << " max_mds " << max_mds;
	  summary.push_back(make_pair(HEALTH_WARN, ss.str()));
	  }
	
	  if ((mds_rank_t)up.size() < max_mds) {
	    stringstream ss;
	    ss << fs_name << " has " << up.size()
	       << " active MDS(s), but has max_mds of " << max_mds;
	    summary.push_back(make_pair(HEALTH_WARN, ss.str()));
	  }
	
	  map<mds_gid_t, mds_info_t>::const_iterator m_end = mds_info.end();
	  set<string> laggy;
	  for (const auto &u : up) {
	    map<mds_gid_t, mds_info_t>::const_iterator m = mds_info.find(u.second);
	    if (m == m_end) {
	      std::cerr << "Up rank " << u.first << " GID " << u.second << " not found!" << std::endl;
	    }
	    ceph_assert(m != m_end);
	    const mds_info_t &mds_info(m->second);
	    if (mds_info.laggy()) {
	      laggy.insert(mds_info.name);
	      if (detail) {
		std::ostringstream oss;
		oss << "mds." << mds_info.name << " at " << mds_info.addrs
		    << " is laggy/unresponsive";
		detail->push_back(make_pair(HEALTH_WARN, oss.str()));
	      }
	    }
	  }
	
	  if (!laggy.empty()) {
	    std::ostringstream oss;
	    oss << "mds " << laggy
		<< ((laggy.size() > 1) ? " are":" is")
		<< " laggy";
	    summary.push_back(make_pair(HEALTH_WARN, oss.str()));
	  }
	
	  if (get_max_mds() > 1 &&
	      was_snaps_ever_allowed() && !allows_multimds_snaps()) {
	    std::ostringstream oss;
	    oss << "multi-active mds while there are snapshots possibly created by pre-mimic MDS";
	    summary.push_back(make_pair(HEALTH_WARN, oss.str()));
	  }
	}
	
	void MDSMap::get_health_checks(health_check_map_t *checks) const
	{
	  // MDS_DAMAGE
	  if (!damaged.empty()) {
	    health_check_t& check = checks->get_or_add("MDS_DAMAGE", HEALTH_ERR,
						       "%num% mds daemon%plurals% damaged",
						       damaged.size());
	    for (auto p : damaged) {
	      std::ostringstream oss;
	      oss << "fs " << fs_name << " mds." << p << " is damaged";
	      check.detail.push_back(oss.str());
	    }
	  }
	
	  // FS_DEGRADED
	  if (is_degraded()) {
	    health_check_t& fscheck = checks->get_or_add(
	      "FS_DEGRADED", HEALTH_WARN,
	      "%num% filesystem%plurals% %isorare% degraded", 1);
	    ostringstream ss;
	    ss << "fs " << fs_name << " is degraded";
	    fscheck.detail.push_back(ss.str());
	
	    list<string> detail;
	    for (mds_rank_t i = mds_rank_t(0); i< get_max_mds(); i++) {
	      if (!is_up(i))
		continue;
	      mds_gid_t gid = up.find(i)->second;
	      map<mds_gid_t,mds_info_t>::const_iterator info = mds_info.find(gid);
	      stringstream ss;
	      ss << "fs " << fs_name << " mds." << info->second.name << " at "
		 << info->second.addrs << " rank " << i;
	      if (is_resolve(i))
		ss << " is resolving";
	      if (is_replay(i))
		ss << " is replaying journal";
	      if (is_rejoin(i))
		ss << " is rejoining";
	      if (is_reconnect(i))
		ss << " is reconnecting to clients";
	      if (ss.str().length())
		detail.push_back(ss.str());
	    }
	  }
	
	  // MDS_UP_LESS_THAN_MAX
	  if ((mds_rank_t)get_num_in_mds() < get_max_mds()) {
	    health_check_t& check = checks->add(
	      "MDS_UP_LESS_THAN_MAX", HEALTH_WARN,
	      "%num% filesystem%plurals% %isorare% online with fewer MDS than max_mds", 1);
	    stringstream ss;
	    ss << "fs " << fs_name << " has " << get_num_in_mds()
	       << " MDS online, but wants " << get_max_mds();
	    check.detail.push_back(ss.str());
	  }
	
	  // MDS_ALL_DOWN
	  if ((mds_rank_t)get_num_up_mds() == 0 && get_max_mds() > 0) {
	    health_check_t &check = checks->add(
	      "MDS_ALL_DOWN", HEALTH_ERR,
	      "%num% filesystem%plurals% %isorare% offline", 1);
	    stringstream ss;
	    ss << "fs " << fs_name << " is offline because no MDS is active for it.";
	    check.detail.push_back(ss.str());
	  }
	
	  if (get_max_mds() > 1 &&
	      was_snaps_ever_allowed() && !allows_multimds_snaps()) {
	    health_check_t &check = checks->add(
	      "MULTIMDS_WITH_OLDSNAPS", HEALTH_ERR,
	      "%num% filesystem%plurals% %isorare% multi-active mds with old snapshots", 1);
	    stringstream ss;
	    ss << "multi-active mds while there are snapshots possibly created by pre-mimic MDS";
	    check.detail.push_back(ss.str());
	  }
	
	  if (get_inline_data_enabled()) {
	    health_check_t &check = checks->add(
	      "FS_INLINE_DATA_DEPRECATED", HEALTH_WARN,
	      "%num% filesystem%plurals% with deprecated feature inline_data", 1);
	    stringstream ss;
	    ss << "fs " << fs_name << " has deprecated feature inline_data enabled.";
	    check.detail.push_back(ss.str());
	  }
	}
	
	void MDSMap::mds_info_t::encode_versioned(bufferlist& bl, uint64_t features) const
	{
	  __u8 v = 9;
	  if (!HAVE_FEATURE(features, SERVER_NAUTILUS)) {
	    v = 7;
	  }
	  ENCODE_START(v, 4, bl);
	  encode(global_id, bl);
	  encode(name, bl);
	  encode(rank, bl);
	  encode(inc, bl);
	  encode((int32_t)state, bl);
	  encode(state_seq, bl);
	  if (v < 8) {
	    encode(addrs.legacy_addr(), bl, features);
	  } else {
	    encode(addrs, bl, features);
	  }
	  encode(laggy_since, bl);
	  encode(MDS_RANK_NONE, bl); /* standby_for_rank */
	  encode(std::string(), bl); /* standby_for_name */
	  encode(export_targets, bl);
	  encode(mds_features, bl);
	  encode(FS_CLUSTER_ID_NONE, bl); /* standby_for_fscid */
	  encode(false, bl);
	  if (v >= 9) {
	    encode(flags, bl);
	  }
	  ENCODE_FINISH(bl);
	}
	
	void MDSMap::mds_info_t::encode_unversioned(bufferlist& bl) const
	{

	  __u8 struct_v = 3;
	  using ceph::encode;

	  encode(struct_v, bl);
	  encode(global_id, bl);
	  encode(name, bl);
	  encode(rank, bl);
	  encode(inc, bl);
	  encode((int32_t)state, bl);
	  encode(state_seq, bl);
	  encode(addrs.legacy_addr(), bl, 0);
	  encode(laggy_since, bl);
	  encode(MDS_RANK_NONE, bl);
	  encode(std::string(), bl);
	  encode(export_targets, bl);
	}
	
	void MDSMap::mds_info_t::decode(bufferlist::const_iterator& bl)
	{
	  DECODE_START_LEGACY_COMPAT_LEN(9, 4, 4, bl);
	  decode(global_id, bl);
	  decode(name, bl);
	  decode(rank, bl);
	  decode(inc, bl);
	  decode((int32_t&)(state), bl);
	  decode(state_seq, bl);
	  decode(addrs, bl);
	  decode(laggy_since, bl);
	  {
	    mds_rank_t standby_for_rank;
	    decode(standby_for_rank, bl);
	  }
	  {
	    std::string standby_for_name;
	    decode(standby_for_name, bl);
	  }
	  if (struct_v >= 2)
	    decode(export_targets, bl);
	  if (struct_v >= 5)
	    decode(mds_features, bl);
	  if (struct_v >= 6) {
	    fs_cluster_id_t standby_for_fscid;
	    decode(standby_for_fscid, bl);
	  }
	  if (struct_v >= 7) {
	    bool standby_replay;
	    decode(standby_replay, bl);
	  }
	  if (struct_v >= 9) {
	    decode(flags, bl);
	  }
	  DECODE_FINISH(bl);
	}
	
	std::string MDSMap::mds_info_t::human_name() const
	{
	  // Like "daemon mds.myhost restarted", "Activating daemon mds.myhost"
	  std::ostringstream out;
	  out << "daemon mds." << name;
	  return out.str();
	}
	
	void MDSMap::encode(bufferlist& bl, uint64_t features) const
	{
	  std::map<mds_rank_t,int32_t> inc;  // Legacy field, fake it so that
	                                     // old-mon peers have something sane
	                                     // during upgrade
	  for (const auto rank : in) {
	    inc.insert(std::make_pair(rank, epoch));
	  }
	
	  using ceph::encode;
	  if ((features & CEPH_FEATURE_PGID64) == 0) {
	    __u16 v = 2;
	    encode(v, bl);
	    encode(epoch, bl);
	    encode(flags, bl);
	    encode(last_failure, bl);
	    encode(root, bl);
	    encode(session_timeout, bl);
	    encode(session_autoclose, bl);
	    encode(max_file_size, bl);
	    encode(max_mds, bl);
	    __u32 n = mds_info.size();
	    encode(n, bl);
	    for (map<mds_gid_t, mds_info_t>::const_iterator i = mds_info.begin();
		i != mds_info.end(); ++i) {
	      encode(i->first, bl);
	      encode(i->second, bl, features);
	    }
	    n = data_pools.size();
	    encode(n, bl);
	    for (const auto p: data_pools) {
	      n = p;
	      encode(n, bl);
	    }
	
	    int32_t m = cas_pool;
	    encode(m, bl);
	    return;
	  } else if ((features & CEPH_FEATURE_MDSENC) == 0) {
	    __u16 v = 3;
	    encode(v, bl);
	    encode(epoch, bl);
	    encode(flags, bl);
	    encode(last_failure, bl);
	    encode(root, bl);
	    encode(session_timeout, bl);
	    encode(session_autoclose, bl);
	    encode(max_file_size, bl);
	    encode(max_mds, bl);
	    __u32 n = mds_info.size();
	    encode(n, bl);
	    for (map<mds_gid_t, mds_info_t>::const_iterator i = mds_info.begin();
		i != mds_info.end(); ++i) {
	      encode(i->first, bl);
	      encode(i->second, bl, features);
	    }
	    encode(data_pools, bl);
	    encode(cas_pool, bl);
	
	    // kclient ignores everything from here
	    __u16 ev = 5;
	    encode(ev, bl);
	    encode(compat, bl);
	    encode(metadata_pool, bl);
	    encode(created, bl);
	    encode(modified, bl);
	    encode(tableserver, bl);
	    encode(in, bl);
	    encode(inc, bl);
	    encode(up, bl);
	    encode(failed, bl);
	    encode(stopped, bl);
	    encode(last_failure_osd_epoch, bl);
	    return;
	  }
	
	  ENCODE_START(5, 4, bl);
	  encode(epoch, bl);
	  encode(flags, bl);
	  encode(last_failure, bl);
	  encode(root, bl);
	  encode(session_timeout, bl);
	  encode(session_autoclose, bl);
	  encode(max_file_size, bl);
	  encode(max_mds, bl);
	  encode(mds_info, bl, features);
	  encode(data_pools, bl);
	  encode(cas_pool, bl);
	
	  // kclient ignores everything from here
	  __u16 ev = 15;
	  encode(ev, bl);
	  encode(compat, bl);
	  encode(metadata_pool, bl);
	  encode(created, bl);
	  encode(modified, bl);
	  encode(tableserver, bl);
	  encode(in, bl);
	  encode(inc, bl);
	  encode(up, bl);
	  encode(failed, bl);
	  encode(stopped, bl);
	  encode(last_failure_osd_epoch, bl);
	  encode(ever_allowed_features, bl);
	  encode(explicitly_allowed_features, bl);
	  encode(inline_data_enabled, bl);
	  encode(enabled, bl);
	  encode(fs_name, bl);
	  encode(damaged, bl);
	  encode(balancer, bl);
	  encode(standby_count_wanted, bl);
	  encode(old_max_mds, bl);
	  encode(min_compat_client, bl);
	  ENCODE_FINISH(bl);
	}
	
	void MDSMap::sanitize(const std::function<bool(int64_t pool)>& pool_exists)
	{
	  /* Before we did stricter checking, it was possible to remove a data pool
	   * without also deleting it from the MDSMap. Check for that here after
	   * decoding the data pools.
	   */
	
	  for (auto it = data_pools.begin(); it != data_pools.end();) {
	    if (!pool_exists(*it)) {
	      dout(0) << "removed non-existant data pool " << *it << " from MDSMap" << dendl;
	      it = data_pools.erase(it);
	    } else {
	      it++;
	    }
	  }
	}
	
	void MDSMap::decode(bufferlist::const_iterator& p)
	{
	  std::map<mds_rank_t,int32_t> inc;  // Legacy field, parse and drop
	
	  cached_up_features = 0;
	  DECODE_START_LEGACY_COMPAT_LEN_16(5, 4, 4, p);
	  decode(epoch, p);
	  decode(flags, p);
	  decode(last_failure, p);
	  decode(root, p);
	  decode(session_timeout, p);
	  decode(session_autoclose, p);
	  decode(max_file_size, p);
	  decode(max_mds, p);
	  decode(mds_info, p);
	  if (struct_v < 3) {
	    __u32 n;
	    decode(n, p);
	    while (n--) {
	      __u32 m;
	      decode(m, p);
	      data_pools.push_back(m);
	    }
	    __s32 s;
	    decode(s, p);
	    cas_pool = s;
	  } else {
	    decode(data_pools, p);
	    decode(cas_pool, p);
	  }
	
	  // kclient ignores everything from here
	  __u16 ev = 1;
	  if (struct_v >= 2)
	    decode(ev, p);
	  if (ev >= 3)
	    decode(compat, p);
	  else
	    compat = get_compat_set_base();
	  if (ev < 5) {
	    __u32 n;
	    decode(n, p);
	    metadata_pool = n;
	  } else {
	    decode(metadata_pool, p);
	  }
	  decode(created, p);
	  decode(modified, p);
	  decode(tableserver, p);
	  decode(in, p);
	  decode(inc, p);
	  decode(up, p);
	  decode(failed, p);
	  decode(stopped, p);
	  if (ev >= 4)
	    decode(last_failure_osd_epoch, p);
	  if (ev >= 6) {
	    if (ev < 10) {
	      // previously this was a bool about snaps, not a flag map
	      bool flag;
	      decode(flag, p);
	      ever_allowed_features = flag ? CEPH_MDSMAP_ALLOW_SNAPS : 0;
	      decode(flag, p);
	      explicitly_allowed_features = flag ? CEPH_MDSMAP_ALLOW_SNAPS : 0;
	    } else {
	      decode(ever_allowed_features, p);
	      decode(explicitly_allowed_features, p);
	    }
	  } else {
	    ever_allowed_features = 0;
	    explicitly_allowed_features = 0;
	  }
	  if (ev >= 7)
	    decode(inline_data_enabled, p);
	
	  if (ev >= 8) {
	    ceph_assert(struct_v >= 5);
	    decode(enabled, p);
	    decode(fs_name, p);
	  } else {
	    if (epoch > 1) {
	      // If an MDS has ever been started, epoch will be greater than 1,
	      // assume filesystem is enabled.
	      enabled = true;
	    } else {
	      // Upgrading from a cluster that never used an MDS, switch off
	      // filesystem until it's explicitly enabled.
	      enabled = false;
	    }
	  }
	
	  if (ev >= 9) {
	    decode(damaged, p);
	  }
	
	  if (ev >= 11) {
	    decode(balancer, p);
	  }
	
	  if (ev >= 12) {
	    decode(standby_count_wanted, p);
	  }
	
	  if (ev >= 13) {
	    decode(old_max_mds, p);
	  }
	
	  if (ev == 14) {
	    int8_t r;
	    decode(r, p);
	    if (r < 0) {
	      min_compat_client = ceph_release_t::unknown;
	    } else {
	      min_compat_client = ceph_release_t{static_cast<uint8_t>(r)};
	    }
	  } else if (ev > 14) {
	    decode(min_compat_client, p);
	  }
	
	  DECODE_FINISH(p);
	}
	
	MDSMap::availability_t MDSMap::is_cluster_available() const
	{
	  if (epoch == 0) {
	    // If I'm a client, this means I'm looking at an MDSMap instance
	    // that was never actually initialized from the mons.  Client should
	    // wait.
	    return TRANSIENT_UNAVAILABLE;
	  }
	
	  // If a rank is marked damage (unavailable until operator intervenes)
	  if (damaged.size()) {
	    return STUCK_UNAVAILABLE;
	  }
	
	  // If no ranks are created (filesystem not initialized)
	  if (in.empty()) {
	    return STUCK_UNAVAILABLE;
	  }
	
	  for (const auto rank : in) {
	    if (up.count(rank) && mds_info.at(up.at(rank)).laggy()) {
	      // This might only be transient, but because we can't see
	      // standbys, we have no way of knowing whether there is a
	      // standby available to replace the laggy guy.
	      return STUCK_UNAVAILABLE;
	    }
	  }
	
	  if (get_num_mds(CEPH_MDS_STATE_ACTIVE) > 0) {
	    // Nobody looks stuck, so indicate to client they should go ahead
	    // and try mounting if anybody is active.  This may include e.g.
	    // one MDS failing over and another active: the client should
	    // proceed to start talking to the active one and let the
	    // transiently-unavailable guy catch up later.
	    return AVAILABLE;
	  } else {
	    // Nothing indicating we were stuck, but nobody active (yet)
	    //return TRANSIENT_UNAVAILABLE;
	
	    // Because we don't have standbys in the MDSMap any more, we can't
	    // reliably indicate transient vs. stuck, so always say stuck so
	    // that the client doesn't block.
	    return STUCK_UNAVAILABLE;
	  }
	}
	
	bool MDSMap::state_transition_valid(DaemonState prev, DaemonState next)
	{
	  bool state_valid = true;
	  if (next != prev) {
	    if (prev == MDSMap::STATE_REPLAY) {
	      if (next != MDSMap::STATE_RESOLVE && next != MDSMap::STATE_RECONNECT) {
	        state_valid = false;
	      }
	    } else if (prev == MDSMap::STATE_REJOIN) {
	      if (next != MDSMap::STATE_ACTIVE &&
		  next != MDSMap::STATE_CLIENTREPLAY &&
		  next != MDSMap::STATE_STOPPED) {
	        state_valid = false;
	      }
	    } else if (prev >= MDSMap::STATE_RESOLVE && prev < MDSMap::STATE_ACTIVE) {
	      // Once I have entered replay, the only allowable transitions are to
	      // the next next along in the sequence.
	      if (next != prev + 1) {
	        state_valid = false;
	      }
	    }
	  }
	
	  return state_valid;
	}
	
	bool MDSMap::check_health(mds_rank_t standby_daemon_count)
	{
	  std::set<mds_rank_t> standbys;
	  get_standby_replay_mds_set(standbys);
	  std::set<mds_rank_t> actives;
	  get_active_mds_set(actives);
	  mds_rank_t standbys_avail = (mds_rank_t)standbys.size()+standby_daemon_count;
	
	  /* If there are standby daemons available/replaying and
	   * standby_count_wanted is unset (default), then we set it to 1. This will
	   * happen during health checks by the mons. Also, during initial creation
	   * of the FS we will have no actives so we don't want to change the default
	   * yet.
	   */
	  if (standby_count_wanted == -1 && actives.size() > 0 && standbys_avail > 0) {
	    set_standby_count_wanted(1);
	    return true;
	  }
	  return false;
	}