Adding upstream version 14.2.21.upstream/14.2.21upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1029 insertions, 0 deletions

diff --git a/src/mds/FSMap.cc b/src/mds/FSMap.cc
new file mode 100644
index 00000000..623e1748
--- /dev/null
+++ b/src/mds/FSMap.cc
@@ -0,0 +1,1029 @@
+// -*- 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 "FSMap.h"
+
+#include "common/StackStringStream.h"
+
+#include <sstream>
+#ifdef WITH_SEASTAR
+#include "crimson/common/config_proxy.h"
+#else
+#include "common/config_proxy.h"
+#endif
+#include "global/global_context.h"
+#include "mon/health_check.h"
+
+using std::stringstream;
+
+void Filesystem::dump(Formatter *f) const
+{
+  f->open_object_section("mdsmap");
+  mds_map.dump(f);
+  f->close_section();
+  f->dump_int("id", fscid);
+}
+
+void FSMap::dump(Formatter *f) const
+{
+  f->dump_int("epoch", epoch);
+  // Use 'default' naming to match 'set-default' CLI
+  f->dump_int("default_fscid", legacy_client_fscid);
+
+  f->open_object_section("compat");
+  compat.dump(f);
+  f->close_section();
+
+  f->open_object_section("feature_flags");
+  f->dump_bool("enable_multiple", enable_multiple);
+  f->dump_bool("ever_enabled_multiple", ever_enabled_multiple);
+  f->close_section();
+
+  f->open_array_section("standbys");
+  for (const auto& [gid, info] : standby_daemons) {
+    f->open_object_section("info");
+    info.dump(f);
+    f->dump_int("epoch", standby_epochs.at(gid));
+    f->close_section();
+  }
+  f->close_section();
+
+  f->open_array_section("filesystems");
+  for (const auto &fs : filesystems) {
+    f->open_object_section("filesystem");
+    fs.second->dump(f);
+    f->close_section();
+  }
+  f->close_section();
+}
+
+void FSMap::generate_test_instances(list<FSMap*>& ls)
+{
+  FSMap *m = new FSMap();
+
+  std::list<MDSMap*> mds_map_instances;
+  MDSMap::generate_test_instances(mds_map_instances);
+
+  int k = 20;
+  for (auto i : mds_map_instances) {
+    auto fs = Filesystem::create();
+    fs->fscid = k++;
+    fs->mds_map = *i;
+    delete i;
+    m->filesystems[fs->fscid] = fs;
+  }
+  mds_map_instances.clear();
+
+  ls.push_back(m);
+}
+
+void FSMap::print(ostream& out) const
+{
+  out << "e" << epoch << std::endl;
+  out << "enable_multiple, ever_enabled_multiple: " << enable_multiple << ","
+      << ever_enabled_multiple << std::endl;
+  out << "compat: " << compat << std::endl;
+  out << "legacy client fscid: " << legacy_client_fscid << std::endl;
+  out << " " << std::endl;
+
+  if (filesystems.empty()) {
+    out << "No filesystems configured" << std::endl;
+  }
+
+  for (const auto& p : filesystems) {
+    p.second->print(out);
+    out << " " << std::endl << " " << std::endl;  // Space out a bit
+  }
+
+  if (!standby_daemons.empty()) {
+    out << "Standby daemons:" << std::endl << " " << std::endl;
+  }
+
+  for (const auto& p : standby_daemons) {
+    out << p.second << std::endl;
+  }
+}
+
+
+
+void FSMap::print_summary(Formatter *f, ostream *out) const
+{
+  if (f) {
+    f->dump_unsigned("epoch", get_epoch());
+    for (const auto &p : filesystems) {
+      auto& fs = p.second;
+      f->dump_unsigned("id", fs->fscid);
+      f->dump_unsigned("up", fs->mds_map.up.size());
+      f->dump_unsigned("in", fs->mds_map.in.size());
+      f->dump_unsigned("max", fs->mds_map.max_mds);
+    }
+  } else {
+    auto count = filesystems.size();
+    if (count <= 3) {
+      bool first = true;
+      for (const auto& p : filesystems) {
+        const auto& fs = p.second;
+        if (!first) {
+          *out << " ";
+        }
+        if (fs->mds_map.is_degraded()) {
+          *out << fs->mds_map.fs_name << ":" << fs->mds_map.up.size() << "/" << fs->mds_map.in.size();
+        } else {
+          *out << fs->mds_map.fs_name << ":" << fs->mds_map.in.size();
+        }
+        first = false;
+      }
+    } else {
+      *out << count << " fs";
+      unsigned degraded = 0;
+      CachedStackStringStream css;
+      *css << " (degraded: ";
+      for (const auto& p : filesystems) {
+        const auto& fs = p.second;
+        if (fs->mds_map.is_degraded()) {
+          degraded++;
+          if (degraded <= 3) {
+            *css << fs->mds_map.fs_name << ":" << fs->mds_map.up.size() << "/" << fs->mds_map.in.size();
+          }
+        }
+      }
+      if (degraded > 0) {
+        if (degraded <= 3) {
+          *css << ")";
+          *out << css->strv();
+        } else {
+          *out << " (degraded: " << degraded << " fs)";
+        }
+      }
+    }
+  }
+
+  if (f) {
+    f->open_array_section("by_rank");
+  }
+
+  std::map<MDSMap::DaemonState,unsigned> by_state;
+  std::map<mds_role_t, std::pair<MDSMap::DaemonState, std::string>> by_rank;
+  by_state[MDSMap::DaemonState::STATE_STANDBY] = standby_daemons.size();
+  for (const auto& [gid, fscid] : mds_roles) {
+    if (fscid == FS_CLUSTER_ID_NONE)
+      continue;
+
+    const auto& info = filesystems.at(fscid)->mds_map.get_info_gid(gid);
+    auto s = std::string(ceph_mds_state_name(info.state));
+    if (info.laggy()) {
+      s += "(laggy or crashed)";
+    }
+
+    if (f) {
+      f->open_object_section("mds");
+      f->dump_unsigned("filesystem_id", fscid);
+      f->dump_unsigned("rank", info.rank);
+      f->dump_string("name", info.name);
+      f->dump_string("status", s);
+      f->dump_unsigned("gid", gid);
+      f->close_section();
+    } else if (info.state != MDSMap::DaemonState::STATE_STANDBY_REPLAY) {
+      by_rank[mds_role_t(fscid, info.rank)] = std::make_pair(info.state, info.name + "=" + s);
+    }
+    by_state[info.state]++;
+  }
+
+  if (f) {
+    f->close_section();
+  } else {
+    if (0 < by_rank.size() && by_rank.size() < 5) {
+      if (filesystems.size() > 1) {
+        // Disambiguate filesystems
+        std::map<std::string, std::string> pretty;
+        for (const auto& [role,status] : by_rank) {
+          const auto &fs_name = filesystems.at(role.fscid)->mds_map.fs_name;
+          CachedStackStringStream css;
+          *css << fs_name << ":" << role.rank;
+          pretty.emplace(std::piecewise_construct, std::forward_as_tuple(css->strv()), std::forward_as_tuple(status.second));
+          --by_state[status.first]; /* already printed! */
+        }
+        *out << " " << pretty;
+      } else {
+        // Omit FSCID in output when only one filesystem exists
+        std::map<mds_rank_t, std::string> shortened;
+        for (const auto& [role,status] : by_rank) {
+          shortened[role.rank] = status.second;
+          --by_state[status.first]; /* already printed! */
+        }
+        *out << " " << shortened;
+      }
+    }
+    for (const auto& [state, count] : by_state) {
+      if (count > 0) {
+        auto s = std::string_view(ceph_mds_state_name(state));
+        *out << " " << count << " " << s;
+      }
+    }
+  }
+
+  if (f) {
+    const auto state = MDSMap::DaemonState::STATE_STANDBY;
+    auto&& name = ceph_mds_state_name(state);
+    auto count = standby_daemons.size();
+    f->dump_unsigned(name, count);
+  }
+
+  size_t failed = 0;
+  size_t damaged = 0;
+  for (const auto& p : filesystems) {
+    auto& fs = p.second;
+    failed += fs->mds_map.failed.size();
+    damaged += fs->mds_map.damaged.size();
+  }
+
+  if (failed > 0) {
+    if (f) {
+      f->dump_unsigned("failed", failed);
+    } else {
+      *out << ", " << failed << " failed";
+    }
+  }
+
+  if (damaged > 0) {
+    if (f) {
+      f->dump_unsigned("damaged", damaged);
+    } else {
+      *out << ", " << damaged << " damaged";
+    }
+  }
+  //if (stopped.size())
+  //out << ", " << stopped.size() << " stopped";
+}
+
+
+Filesystem::ref FSMap::create_filesystem(std::string_view name,
+    int64_t metadata_pool, int64_t data_pool, uint64_t features)
+{
+  auto fs = Filesystem::create();
+  fs->mds_map.epoch = epoch;
+  fs->mds_map.fs_name = name;
+  fs->mds_map.data_pools.push_back(data_pool);
+  fs->mds_map.metadata_pool = metadata_pool;
+  fs->mds_map.cas_pool = -1;
+  fs->mds_map.compat = compat;
+  fs->mds_map.created = ceph_clock_now();
+  fs->mds_map.modified = ceph_clock_now();
+  fs->mds_map.enabled = true;
+  if (features & CEPH_FEATURE_SERVER_JEWEL) {
+    fs->fscid = next_filesystem_id++;
+    // ANONYMOUS is only for upgrades from legacy mdsmaps, we should
+    // have initialized next_filesystem_id such that it's never used here.
+    ceph_assert(fs->fscid != FS_CLUSTER_ID_ANONYMOUS);
+  } else {
+    // Use anon fscid because this will get thrown away when encoding
+    // as legacy MDSMap for legacy mons.
+    ceph_assert(filesystems.empty());
+    fs->fscid = FS_CLUSTER_ID_ANONYMOUS;
+  }
+  filesystems[fs->fscid] = fs;
+
+  // Created first filesystem?  Set it as the one
+  // for legacy clients to use
+  if (filesystems.size() == 1) {
+    legacy_client_fscid = fs->fscid;
+  }
+
+  return fs;
+}
+
+void FSMap::reset_filesystem(fs_cluster_id_t fscid)
+{
+  auto fs = get_filesystem(fscid);
+  auto new_fs = Filesystem::create();
+
+  // Populate rank 0 as existing (so don't go into CREATING)
+  // but failed (so that next available MDS is assigned the rank)
+  new_fs->mds_map.in.insert(mds_rank_t(0));
+  new_fs->mds_map.failed.insert(mds_rank_t(0));
+
+  // Carry forward what makes sense
+  new_fs->fscid = fs->fscid;
+  new_fs->mds_map.inline_data_enabled = fs->mds_map.inline_data_enabled;
+  new_fs->mds_map.data_pools = fs->mds_map.data_pools;
+  new_fs->mds_map.metadata_pool = fs->mds_map.metadata_pool;
+  new_fs->mds_map.cas_pool = fs->mds_map.cas_pool;
+  new_fs->mds_map.fs_name = fs->mds_map.fs_name;
+  new_fs->mds_map.compat = compat;
+  new_fs->mds_map.created = ceph_clock_now();
+  new_fs->mds_map.modified = ceph_clock_now();
+  new_fs->mds_map.standby_count_wanted = fs->mds_map.standby_count_wanted;
+  new_fs->mds_map.enabled = true;
+
+  // Remember mds ranks that have ever started. (They should load old inotable
+  // instead of creating new one if they start again.)
+  new_fs->mds_map.stopped.insert(fs->mds_map.in.begin(), fs->mds_map.in.end());
+  new_fs->mds_map.stopped.insert(fs->mds_map.stopped.begin(), fs->mds_map.stopped.end());
+  new_fs->mds_map.stopped.erase(mds_rank_t(0));
+
+  // Persist the new FSMap
+  filesystems[new_fs->fscid] = new_fs;
+}
+
+void FSMap::get_health(list<pair<health_status_t,string> >& summary,
+			list<pair<health_status_t,string> > *detail) const
+{
+  mds_rank_t standby_count_wanted = 0;
+  for (const auto &i : filesystems) {
+    const auto &fs = i.second;
+
+    // TODO: move get_health up into here so that we can qualify
+    // all the messages with what filesystem they're talking about
+    fs->mds_map.get_health(summary, detail);
+
+    standby_count_wanted = std::max(standby_count_wanted, fs->mds_map.get_standby_count_wanted((mds_rank_t)standby_daemons.size()));
+  }
+
+  if (standby_count_wanted) {
+    std::ostringstream oss;
+    oss << "insufficient standby daemons available: have " << standby_daemons.size() << "; want " << standby_count_wanted << " more";
+    summary.push_back(make_pair(HEALTH_WARN, oss.str()));
+  }
+}
+
+bool FSMap::check_health(void)
+{
+  bool changed = false;
+  for (auto &i : filesystems) {
+    changed |= i.second->mds_map.check_health((mds_rank_t)standby_daemons.size());
+  }
+  return changed;
+}
+
+void FSMap::get_health_checks(health_check_map_t *checks) const
+{
+  mds_rank_t standby_count_wanted = 0;
+  for (const auto &i : filesystems) {
+    const auto &fs = i.second;
+    health_check_map_t fschecks;
+
+    fs->mds_map.get_health_checks(&fschecks);
+
+    // Some of the failed ranks might be transient (i.e. there are standbys
+    // ready to replace them).  We will report only on "stuck" failed, i.e.
+    // ranks which are failed and have no standby replacement available.
+    std::set<mds_rank_t> stuck_failed;
+
+    for (const auto &rank : fs->mds_map.failed) {
+      auto&& replacement = find_replacement_for({fs->fscid, rank}, {});
+      if (replacement == MDS_GID_NONE) {
+        stuck_failed.insert(rank);
+      }
+    }
+
+    // FS_WITH_FAILED_MDS
+    if (!stuck_failed.empty()) {
+      health_check_t& fscheck = checks->get_or_add(
+        "FS_WITH_FAILED_MDS", HEALTH_WARN,
+        "%num% filesystem%plurals% %hasorhave% a failed mds daemon");
+      ostringstream ss;
+      ss << "fs " << fs->mds_map.fs_name << " has " << stuck_failed.size()
+         << " failed mds" << (stuck_failed.size() > 1 ? "s" : "");
+      fscheck.detail.push_back(ss.str()); }
+
+    checks->merge(fschecks);
+    standby_count_wanted = std::max(
+      standby_count_wanted,
+      fs->mds_map.get_standby_count_wanted((mds_rank_t)standby_daemons.size()));
+  }
+
+  // MDS_INSUFFICIENT_STANDBY
+  if (standby_count_wanted) {
+    std::ostringstream oss, dss;
+    oss << "insufficient standby MDS daemons available";
+    auto& d = checks->get_or_add("MDS_INSUFFICIENT_STANDBY", HEALTH_WARN, oss.str());
+    dss << "have " << standby_daemons.size() << "; want " << standby_count_wanted
+	<< " more";
+    d.detail.push_back(dss.str());
+  }
+}
+
+void FSMap::encode(bufferlist& bl, uint64_t features) const
+{
+  if (features & CEPH_FEATURE_SERVER_JEWEL) {
+    ENCODE_START(7, 6, bl);
+    encode(epoch, bl);
+    encode(next_filesystem_id, bl);
+    encode(legacy_client_fscid, bl);
+    encode(compat, bl);
+    encode(enable_multiple, bl);
+    {
+      std::vector<Filesystem::ref> v;
+      v.reserve(filesystems.size());
+      for (auto& p : filesystems) v.emplace_back(p.second);
+      encode(v, bl, features);
+    }
+    encode(mds_roles, bl);
+    encode(standby_daemons, bl, features);
+    encode(standby_epochs, bl);
+    encode(ever_enabled_multiple, bl);
+    ENCODE_FINISH(bl);
+  } else {
+    if (filesystems.empty()) {
+      MDSMap disabled_map;
+      disabled_map.epoch = epoch;
+      disabled_map.encode(bl, features);
+    } else {
+      // MDSMonitor should never have created multiple filesystems
+      // until the quorum features indicated Jewel
+      ceph_assert(filesystems.size() == 1);
+      auto fs = filesystems.begin()->second;
+
+      // Take the MDSMap for the enabled filesystem, and populated its
+      // mds_info with the standbys to get a pre-jewel-style mon MDSMap.
+      MDSMap full_mdsmap = fs->mds_map;
+      full_mdsmap.epoch = epoch;
+      for (const auto &p : standby_daemons) {
+        full_mdsmap.mds_info[p.first] = p.second;
+      }
+
+      // Old MDSMaps don't set rank on standby replay daemons
+      for (auto &i : full_mdsmap.mds_info) {
+        auto &info = i.second;
+        if (info.state == MDSMap::STATE_STANDBY_REPLAY) {
+          info.rank = MDS_RANK_NONE;
+        }
+      }
+
+      full_mdsmap.encode(bl, features);
+    }
+  }
+}
+
+void FSMap::decode(bufferlist::const_iterator& p)
+{
+  // The highest MDSMap encoding version before we changed the
+  // MDSMonitor to store an FSMap instead of an MDSMap was
+  // 5, so anything older than 6 is decoded as an MDSMap,
+  // and anything newer is decoded as an FSMap.
+  DECODE_START_LEGACY_COMPAT_LEN_16(7, 4, 4, p);
+  if (struct_v < 6) {
+    // Because the mon used to store an MDSMap where we now
+    // store an FSMap, FSMap knows how to decode the legacy
+    // MDSMap format (it never needs to encode it though).
+    MDSMap legacy_mds_map;
+
+    // Decoding an MDSMap (upgrade)
+    decode(epoch, p);
+    decode(legacy_mds_map.flags, p);
+    decode(legacy_mds_map.last_failure, p);
+    decode(legacy_mds_map.root, p);
+    decode(legacy_mds_map.session_timeout, p);
+    decode(legacy_mds_map.session_autoclose, p);
+    decode(legacy_mds_map.max_file_size, p);
+    decode(legacy_mds_map.max_mds, p);
+    decode(legacy_mds_map.mds_info, p);
+    if (struct_v < 3) {
+      __u32 n;
+      decode(n, p);
+      while (n--) {
+        __u32 m;
+        decode(m, p);
+        legacy_mds_map.data_pools.push_back(m);
+      }
+      __s32 s;
+      decode(s, p);
+      legacy_mds_map.cas_pool = s;
+    } else {
+      decode(legacy_mds_map.data_pools, p);
+      decode(legacy_mds_map.cas_pool, p);
+    }
+
+    // kclient ignores everything from here
+    __u16 ev = 1;
+    if (struct_v >= 2)
+      decode(ev, p);
+    if (ev >= 3)
+      decode(legacy_mds_map.compat, p);
+    else
+      legacy_mds_map.compat = MDSMap::get_compat_set_base();
+    if (ev < 5) {
+      __u32 n;
+      decode(n, p);
+      legacy_mds_map.metadata_pool = n;
+    } else {
+      decode(legacy_mds_map.metadata_pool, p);
+    }
+    decode(legacy_mds_map.created, p);
+    decode(legacy_mds_map.modified, p);
+    decode(legacy_mds_map.tableserver, p);
+    decode(legacy_mds_map.in, p);
+    std::map<mds_rank_t,int32_t> inc;  // Legacy field, parse and drop
+    decode(inc, p);
+    decode(legacy_mds_map.up, p);
+    decode(legacy_mds_map.failed, p);
+    decode(legacy_mds_map.stopped, p);
+    if (ev >= 4)
+      decode(legacy_mds_map.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);
+	legacy_mds_map.ever_allowed_features = flag ?
+	  CEPH_MDSMAP_ALLOW_SNAPS : 0;
+	decode(flag, p);
+	legacy_mds_map.explicitly_allowed_features = flag ?
+	  CEPH_MDSMAP_ALLOW_SNAPS : 0;
+      } else {
+	decode(legacy_mds_map.ever_allowed_features, p);
+	decode(legacy_mds_map.explicitly_allowed_features, p);
+      }
+    } else {
+      legacy_mds_map.ever_allowed_features = 0;
+      legacy_mds_map.explicitly_allowed_features = 0;
+    }
+    if (ev >= 7)
+      decode(legacy_mds_map.inline_data_enabled, p);
+
+    if (ev >= 8) {
+      ceph_assert(struct_v >= 5);
+      decode(legacy_mds_map.enabled, p);
+      decode(legacy_mds_map.fs_name, p);
+    } else {
+      legacy_mds_map.fs_name = "default";
+      if (epoch > 1) {
+        // If an MDS has ever been started, epoch will be greater than 1,
+        // assume filesystem is enabled.
+        legacy_mds_map.enabled = true;
+      } else {
+        // Upgrading from a cluster that never used an MDS, switch off
+        // filesystem until it's explicitly enabled.
+        legacy_mds_map.enabled = false;
+      }
+    }
+
+    if (ev >= 9) {
+      decode(legacy_mds_map.damaged, p);
+    }
+
+    // We're upgrading, populate filesystems from the legacy fields
+    filesystems.clear();
+    standby_daemons.clear();
+    standby_epochs.clear();
+    mds_roles.clear();
+    compat = legacy_mds_map.compat;
+    enable_multiple = false;
+
+    // Synthesise a Filesystem from legacy_mds_map, if enabled
+    if (legacy_mds_map.enabled) {
+      // Construct a Filesystem from the legacy MDSMap
+      auto migrate_fs = Filesystem::create();
+      migrate_fs->fscid = FS_CLUSTER_ID_ANONYMOUS;
+      migrate_fs->mds_map = legacy_mds_map;
+      migrate_fs->mds_map.epoch = epoch;
+      filesystems[migrate_fs->fscid] = migrate_fs;
+
+      // List of GIDs that had invalid states
+      std::set<mds_gid_t> drop_gids;
+
+      // Construct mds_roles, standby_daemons, and remove
+      // standbys from the MDSMap in the Filesystem.
+      for (const auto& [gid, info] : migrate_fs->mds_map.mds_info) {
+        if (info.state == MDSMap::STATE_STANDBY_REPLAY) {
+          /* drop any legacy standby-replay daemons */
+          drop_gids.insert(gid);
+        } else if (info.rank == MDS_RANK_NONE) {
+          if (info.state != MDSMap::STATE_STANDBY) {
+            // Old MDSMaps can have down:dne here, which
+            // is invalid in an FSMap (#17837)
+            drop_gids.insert(gid);
+          } else {
+            insert(info); // into standby_daemons
+          }
+        } else {
+          mds_roles[gid] = migrate_fs->fscid;
+        }
+      }
+      for (const auto &p : standby_daemons) {
+        // Erase from this Filesystem's MDSMap, because it has
+        // been copied into FSMap::Standby_daemons above
+        migrate_fs->mds_map.mds_info.erase(p.first);
+      }
+      for (const auto &gid : drop_gids) {
+        // Throw away all info for this MDS because it was identified
+        // as having invalid state above.
+        migrate_fs->mds_map.mds_info.erase(gid);
+      }
+
+      legacy_client_fscid = migrate_fs->fscid;
+    } else {
+      legacy_client_fscid = FS_CLUSTER_ID_NONE;
+    }
+  } else {
+    decode(epoch, p);
+    decode(next_filesystem_id, p);
+    decode(legacy_client_fscid, p);
+    decode(compat, p);
+    decode(enable_multiple, p);
+    {
+      std::vector<Filesystem::ref> v;
+      decode(v, p);
+      filesystems.clear();
+      for (auto& ref : v) {
+        auto em = filesystems.emplace(std::piecewise_construct, std::forward_as_tuple(ref->fscid), std::forward_as_tuple(std::move(ref)));
+        ceph_assert(em.second);
+      }
+    }
+    decode(mds_roles, p);
+    decode(standby_daemons, p);
+    decode(standby_epochs, p);
+    if (struct_v >= 7) {
+      decode(ever_enabled_multiple, p);
+    }
+  }
+
+  DECODE_FINISH(p);
+}
+
+void FSMap::sanitize(const std::function<bool(int64_t pool)>& pool_exists)
+{
+  for (auto &fs : filesystems) {
+    fs.second->mds_map.sanitize(pool_exists);
+  }
+}
+
+void Filesystem::encode(bufferlist& bl, uint64_t features) const
+{
+  ENCODE_START(1, 1, bl);
+  encode(fscid, bl);
+  bufferlist mdsmap_bl;
+  mds_map.encode(mdsmap_bl, features);
+  encode(mdsmap_bl, bl);
+  ENCODE_FINISH(bl);
+}
+
+void Filesystem::decode(bufferlist::const_iterator& p)
+{
+  DECODE_START(1, p);
+  decode(fscid, p);
+  bufferlist mdsmap_bl;
+  decode(mdsmap_bl, p);
+  auto mdsmap_bl_iter = mdsmap_bl.cbegin();
+  mds_map.decode(mdsmap_bl_iter);
+  DECODE_FINISH(p);
+}
+
+int FSMap::parse_filesystem(
+      std::string_view ns_str,
+      Filesystem::const_ref* result
+      ) const
+{
+  std::string ns_err;
+  std::string s(ns_str);
+  fs_cluster_id_t fscid = strict_strtol(s.c_str(), 10, &ns_err);
+  if (!ns_err.empty() || filesystems.count(fscid) == 0) {
+    for (auto &fs : filesystems) {
+      if (fs.second->mds_map.fs_name == s) {
+        *result = std::const_pointer_cast<const Filesystem>(fs.second);
+        return 0;
+      }
+    }
+    return -ENOENT;
+  } else {
+    *result = get_filesystem(fscid);
+    return 0;
+  }
+}
+
+void Filesystem::print(std::ostream &out) const
+{
+  out << "Filesystem '" << mds_map.fs_name
+      << "' (" << fscid << ")" << std::endl;
+  mds_map.print(out);
+}
+
+mds_gid_t FSMap::get_available_standby() const
+{
+  for (const auto& [gid, info] : standby_daemons) {
+    ceph_assert(info.rank == MDS_RANK_NONE);
+    ceph_assert(info.state == MDSMap::STATE_STANDBY);
+
+    if (info.laggy() || info.is_frozen()) {
+      continue;
+    }
+
+    return gid;
+  }
+  return MDS_GID_NONE;
+}
+
+mds_gid_t FSMap::find_replacement_for(mds_role_t role, std::string_view name) const
+{
+  auto&& fs = get_filesystem(role.fscid);
+
+  // First see if we have a STANDBY_REPLAY
+  for (const auto& [gid, info] : fs->mds_map.mds_info) {
+    if (info.rank == role.rank && info.state == MDSMap::STATE_STANDBY_REPLAY) {
+      if (info.is_frozen()) {
+        /* the standby-replay is frozen, do nothing! */
+        return MDS_GID_NONE;
+      } else {
+        return gid;
+      }
+    }
+  }
+
+  return get_available_standby();
+}
+
+void FSMap::sanity() const
+{
+  if (legacy_client_fscid != FS_CLUSTER_ID_NONE) {
+    ceph_assert(filesystems.count(legacy_client_fscid) == 1);
+  }
+
+  for (const auto &i : filesystems) {
+    auto fs = i.second;
+    ceph_assert(fs->mds_map.compat.compare(compat) == 0);
+    ceph_assert(fs->fscid == i.first);
+    for (const auto &j : fs->mds_map.mds_info) {
+      ceph_assert(j.second.rank != MDS_RANK_NONE);
+      ceph_assert(mds_roles.count(j.first) == 1);
+      ceph_assert(standby_daemons.count(j.first) == 0);
+      ceph_assert(standby_epochs.count(j.first) == 0);
+      ceph_assert(mds_roles.at(j.first) == i.first);
+      if (j.second.state != MDSMap::STATE_STANDBY_REPLAY) {
+        ceph_assert(fs->mds_map.up.at(j.second.rank) == j.first);
+        ceph_assert(fs->mds_map.failed.count(j.second.rank) == 0);
+        ceph_assert(fs->mds_map.damaged.count(j.second.rank) == 0);
+      }
+    }
+
+    for (const auto &j : fs->mds_map.up) {
+      mds_rank_t rank = j.first;
+      ceph_assert(fs->mds_map.in.count(rank) == 1);
+      mds_gid_t gid = j.second;
+      ceph_assert(fs->mds_map.mds_info.count(gid) == 1);
+    }
+  }
+
+  for (const auto &i : standby_daemons) {
+    ceph_assert(i.second.state == MDSMap::STATE_STANDBY);
+    ceph_assert(i.second.rank == MDS_RANK_NONE);
+    ceph_assert(i.second.global_id == i.first);
+    ceph_assert(standby_epochs.count(i.first) == 1);
+    ceph_assert(mds_roles.count(i.first) == 1);
+    ceph_assert(mds_roles.at(i.first) == FS_CLUSTER_ID_NONE);
+  }
+
+  for (const auto &i : standby_epochs) {
+    ceph_assert(standby_daemons.count(i.first) == 1);
+  }
+
+  for (const auto &i : mds_roles) {
+    if (i.second == FS_CLUSTER_ID_NONE) {
+      ceph_assert(standby_daemons.count(i.first) == 1);
+    } else {
+      ceph_assert(filesystems.count(i.second) == 1);
+      ceph_assert(filesystems.at(i.second)->mds_map.mds_info.count(i.first) == 1);
+    }
+  }
+}
+
+void FSMap::promote(
+    mds_gid_t standby_gid,
+    Filesystem& filesystem,
+    mds_rank_t assigned_rank)
+{
+  ceph_assert(gid_exists(standby_gid));
+  bool is_standby_replay = mds_roles.at(standby_gid) != FS_CLUSTER_ID_NONE;
+  if (!is_standby_replay) {
+    ceph_assert(standby_daemons.count(standby_gid));
+    ceph_assert(standby_daemons.at(standby_gid).state == MDSMap::STATE_STANDBY);
+  }
+
+  MDSMap &mds_map = filesystem.mds_map;
+
+  // Insert daemon state to Filesystem
+  if (!is_standby_replay) {
+    mds_map.mds_info[standby_gid] = standby_daemons.at(standby_gid);
+  } else {
+    ceph_assert(mds_map.mds_info.count(standby_gid));
+    ceph_assert(mds_map.mds_info.at(standby_gid).state == MDSMap::STATE_STANDBY_REPLAY);
+    ceph_assert(mds_map.mds_info.at(standby_gid).rank == assigned_rank);
+  }
+  MDSMap::mds_info_t &info = mds_map.mds_info[standby_gid];
+
+  if (mds_map.stopped.erase(assigned_rank)) {
+    // The cluster is being expanded with a stopped rank
+    info.state = MDSMap::STATE_STARTING;
+  } else if (!mds_map.is_in(assigned_rank)) {
+    // The cluster is being expanded with a new rank
+    info.state = MDSMap::STATE_CREATING;
+  } else {
+    // An existing rank is being assigned to a replacement
+    info.state = MDSMap::STATE_REPLAY;
+    mds_map.failed.erase(assigned_rank);
+  }
+  info.rank = assigned_rank;
+  info.inc = epoch;
+  mds_roles[standby_gid] = filesystem.fscid;
+
+  // Update the rank state in Filesystem
+  mds_map.in.insert(assigned_rank);
+  mds_map.up[assigned_rank] = standby_gid;
+
+  // Remove from the list of standbys
+  if (!is_standby_replay) {
+    standby_daemons.erase(standby_gid);
+    standby_epochs.erase(standby_gid);
+  }
+
+  // Indicate that Filesystem has been modified
+  mds_map.epoch = epoch;
+}
+
+void FSMap::assign_standby_replay(
+    const mds_gid_t standby_gid,
+    const fs_cluster_id_t leader_ns,
+    const mds_rank_t leader_rank)
+{
+  ceph_assert(mds_roles.at(standby_gid) == FS_CLUSTER_ID_NONE);
+  ceph_assert(gid_exists(standby_gid));
+  ceph_assert(!gid_has_rank(standby_gid));
+  ceph_assert(standby_daemons.count(standby_gid));
+
+  // Insert to the filesystem
+  auto fs = filesystems.at(leader_ns);
+  fs->mds_map.mds_info[standby_gid] = standby_daemons.at(standby_gid);
+  fs->mds_map.mds_info[standby_gid].rank = leader_rank;
+  fs->mds_map.mds_info[standby_gid].state = MDSMap::STATE_STANDBY_REPLAY;
+  mds_roles[standby_gid] = leader_ns;
+
+  // Remove from the list of standbys
+  standby_daemons.erase(standby_gid);
+  standby_epochs.erase(standby_gid);
+
+  // Indicate that Filesystem has been modified
+  fs->mds_map.epoch = epoch;
+}
+
+void FSMap::erase(mds_gid_t who, epoch_t blacklist_epoch)
+{
+  if (mds_roles.at(who) == FS_CLUSTER_ID_NONE) {
+    standby_daemons.erase(who);
+    standby_epochs.erase(who);
+  } else {
+    auto &fs = filesystems.at(mds_roles.at(who));
+    const auto &info = fs->mds_map.mds_info.at(who);
+    if (info.state != MDSMap::STATE_STANDBY_REPLAY) {
+      if (info.state == MDSMap::STATE_CREATING) {
+        // If this gid didn't make it past CREATING, then forget
+        // the rank ever existed so that next time it's handed out
+        // to a gid it'll go back into CREATING.
+        fs->mds_map.in.erase(info.rank);
+      } else {
+        // Put this rank into the failed list so that the next available
+        // STANDBY will pick it up.
+        fs->mds_map.failed.insert(info.rank);
+      }
+      ceph_assert(fs->mds_map.up.at(info.rank) == info.global_id);
+      fs->mds_map.up.erase(info.rank);
+    }
+    fs->mds_map.mds_info.erase(who);
+    fs->mds_map.last_failure_osd_epoch = blacklist_epoch;
+    fs->mds_map.epoch = epoch;
+  }
+
+  mds_roles.erase(who);
+}
+
+void FSMap::damaged(mds_gid_t who, epoch_t blacklist_epoch)
+{
+  ceph_assert(mds_roles.at(who) != FS_CLUSTER_ID_NONE);
+  auto fs = filesystems.at(mds_roles.at(who));
+  mds_rank_t rank = fs->mds_map.mds_info[who].rank;
+
+  erase(who, blacklist_epoch);
+  fs->mds_map.failed.erase(rank);
+  fs->mds_map.damaged.insert(rank);
+
+  ceph_assert(fs->mds_map.epoch == epoch);
+}
+
+/**
+ * Update to indicate that the rank `rank` is to be removed
+ * from the damaged list of the filesystem `fscid`
+ */
+bool FSMap::undamaged(const fs_cluster_id_t fscid, const mds_rank_t rank)
+{
+  auto fs = filesystems.at(fscid);
+
+  if (fs->mds_map.damaged.erase(rank)) {
+    fs->mds_map.failed.insert(rank);
+    fs->mds_map.epoch = epoch;
+    return true;
+  } else {
+    return false;
+  }
+}
+
+void FSMap::insert(const MDSMap::mds_info_t &new_info)
+{
+  ceph_assert(new_info.state == MDSMap::STATE_STANDBY);
+  ceph_assert(new_info.rank == MDS_RANK_NONE);
+  mds_roles[new_info.global_id] = FS_CLUSTER_ID_NONE;
+  standby_daemons[new_info.global_id] = new_info;
+  standby_epochs[new_info.global_id] = epoch;
+}
+
+std::list<mds_gid_t> FSMap::stop(mds_gid_t who)
+{
+  ceph_assert(mds_roles.at(who) != FS_CLUSTER_ID_NONE);
+  auto fs = filesystems.at(mds_roles.at(who));
+  const auto &info = fs->mds_map.mds_info.at(who);
+  fs->mds_map.up.erase(info.rank);
+  fs->mds_map.in.erase(info.rank);
+  fs->mds_map.stopped.insert(info.rank);
+
+  // Also drop any standby replays that were following this rank
+  std::list<mds_gid_t> standbys;
+  for (const auto &i : fs->mds_map.mds_info) {
+    const auto &other_gid = i.first;
+    const auto &other_info = i.second;
+    if (other_info.rank == info.rank
+        && other_info.state == MDSMap::STATE_STANDBY_REPLAY) {
+      standbys.push_back(other_gid);
+      erase(other_gid, 0);
+    }
+  }
+
+  fs->mds_map.mds_info.erase(who);
+  mds_roles.erase(who);
+
+  fs->mds_map.epoch = epoch;
+
+  return standbys;
+}
+
+
+/**
+ * Given one of the following forms:
+ *   <fs name>:<rank>
+ *   <fs id>:<rank>
+ *   <rank>
+ *
+ * Parse into a mds_role_t.  The rank-only form is only valid
+ * if legacy_client_ns is set.
+ */
+int FSMap::parse_role(
+    std::string_view role_str,
+    mds_role_t *role,
+    std::ostream &ss) const
+{
+  size_t colon_pos = role_str.find(":");
+  size_t rank_pos;
+  Filesystem::const_ref fs;
+  if (colon_pos == std::string::npos) {
+    if (legacy_client_fscid == FS_CLUSTER_ID_NONE) {
+      ss << "No filesystem selected";
+      return -ENOENT;
+    }
+    fs = get_filesystem(legacy_client_fscid);
+    rank_pos = 0;
+  } else {
+    if (parse_filesystem(role_str.substr(0, colon_pos), &fs) < 0) {
+      ss << "Invalid filesystem";
+      return -ENOENT;
+    }
+    rank_pos = colon_pos+1;
+  }
+
+  mds_rank_t rank;
+  std::string err;
+  std::string rank_str(role_str.substr(rank_pos));
+  long rank_i = strict_strtol(rank_str.c_str(), 10, &err);
+  if (rank_i < 0 || !err.empty()) {
+    ss << "Invalid rank '" << rank_str << "'";
+    return -EINVAL;
+  } else {
+    rank = rank_i;
+  }
+
+  if (fs->mds_map.in.count(rank) == 0) {
+    ss << "Rank '" << rank << "' not found";
+    return -ENOENT;
+  }
+
+  *role = {fs->fscid, rank};
+
+  return 0;
+}