Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream

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

1 files changed, 1516 insertions, 0 deletions

diff --git a/src/mon/FSCommands.cc b/src/mon/FSCommands.cc
new file mode 100644
index 000000000..0b1bb2a03
--- /dev/null
+++ b/src/mon/FSCommands.cc
@@ -0,0 +1,1516 @@
+// -*- 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) 2017 Red Hat Ltd
+ *
+ * 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 "OSDMonitor.h"
+
+#include "FSCommands.h"
+#include "MDSMonitor.h"
+#include "MgrStatMonitor.h"
+#include "mds/cephfs_features.h"
+
+using TOPNSPC::common::cmd_getval;
+
+using std::dec;
+using std::hex;
+using std::list;
+using std::map;
+using std::make_pair;
+using std::pair;
+using std::set;
+using std::string;
+using std::to_string;
+using std::vector;
+
+using ceph::bufferlist;
+using ceph::decode;
+using ceph::encode;
+using ceph::ErasureCodeInterfaceRef;
+using ceph::ErasureCodeProfile;
+using ceph::Formatter;
+using ceph::JSONFormatter;
+using ceph::make_message;
+using ceph::mono_clock;
+using ceph::mono_time;
+
+class FlagSetHandler : public FileSystemCommandHandler
+{
+  public:
+  FlagSetHandler()
+    : FileSystemCommandHandler("fs flag set")
+  {
+  }
+
+  int handle(
+      Monitor *mon,
+      FSMap& fsmap,
+      MonOpRequestRef op,
+      const cmdmap_t& cmdmap,
+      std::ostream &ss) override
+  {
+    string flag_name;
+    cmd_getval(cmdmap, "flag_name", flag_name);
+
+    string flag_val;
+    cmd_getval(cmdmap, "val", flag_val);
+
+    bool sure = false;
+    cmd_getval(cmdmap, "yes_i_really_mean_it", sure);
+
+    if (flag_name == "enable_multiple") {
+      bool flag_bool = false;
+      int r = parse_bool(flag_val, &flag_bool, ss);
+      if (r != 0) {
+        ss << "Invalid boolean value '" << flag_val << "'";
+        return r;
+      }
+
+      fsmap.set_enable_multiple(flag_bool);
+      return 0;
+    } else {
+      ss << "Unknown flag '" << flag_name << "'";
+      return -EINVAL;
+    }
+  }
+};
+
+class FailHandler : public FileSystemCommandHandler
+{
+  public:
+  FailHandler()
+    : FileSystemCommandHandler("fs fail")
+  {
+  }
+
+  int handle(
+      Monitor* mon,
+      FSMap& fsmap,
+      MonOpRequestRef op,
+      const cmdmap_t& cmdmap,
+      std::ostream& ss) override
+  {
+    if (!mon->osdmon()->is_writeable()) {
+      // not allowed to write yet, so retry when we can
+      mon->osdmon()->wait_for_writeable(op, new PaxosService::C_RetryMessage(mon->mdsmon(), op));
+      return -EAGAIN;
+    }
+
+    std::string fs_name;
+    if (!cmd_getval(cmdmap, "fs_name", fs_name) || fs_name.empty()) {
+      ss << "Missing filesystem name";
+      return -EINVAL;
+    }
+
+    auto fs = fsmap.get_filesystem(fs_name);
+
+    auto f = [](auto fs) {
+      fs->mds_map.set_flag(CEPH_MDSMAP_NOT_JOINABLE);
+    };
+    fsmap.modify_filesystem(fs->fscid, std::move(f));
+
+    std::vector<mds_gid_t> to_fail;
+    for (const auto& p : fs->mds_map.get_mds_info()) {
+      to_fail.push_back(p.first);
+    }
+
+    for (const auto& gid : to_fail) {
+      mon->mdsmon()->fail_mds_gid(fsmap, gid);
+    }
+    if (!to_fail.empty()) {
+      mon->osdmon()->propose_pending();
+    }
+
+    ss << fs_name;
+    ss << " marked not joinable; MDS cannot join the cluster. All MDS ranks marked failed.";
+
+    return 0;
+  }
+};
+
+class FsNewHandler : public FileSystemCommandHandler
+{
+  public:
+  explicit FsNewHandler(Paxos *paxos)
+    : FileSystemCommandHandler("fs new"), m_paxos(paxos)
+  {
+  }
+
+  bool batched_propose() override {
+    return true;
+  }
+
+  int handle(
+      Monitor *mon,
+      FSMap& fsmap,
+      MonOpRequestRef op,
+      const cmdmap_t& cmdmap,
+      std::ostream &ss) override
+  {
+    ceph_assert(m_paxos->is_plugged());
+
+    string metadata_name;
+    cmd_getval(cmdmap, "metadata", metadata_name);
+    int64_t metadata = mon->osdmon()->osdmap.lookup_pg_pool_name(metadata_name);
+    if (metadata < 0) {
+      ss << "pool '" << metadata_name << "' does not exist";
+      return -ENOENT;
+    }
+
+    string data_name;
+    cmd_getval(cmdmap, "data", data_name);
+    int64_t data = mon->osdmon()->osdmap.lookup_pg_pool_name(data_name);
+    if (data < 0) {
+      ss << "pool '" << data_name << "' does not exist";
+      return -ENOENT;
+    }
+    if (data == 0) {
+      ss << "pool '" << data_name << "' has id 0, which CephFS does not allow. Use another pool or recreate it to get a non-zero pool id.";
+      return -EINVAL;
+    }
+
+    string fs_name;
+    cmd_getval(cmdmap, "fs_name", fs_name);
+    if (fs_name.empty()) {
+        // Ensure fs name is not empty so that we can implement
+        // commmands that refer to FS by name in future.
+        ss << "Filesystem name may not be empty";
+        return -EINVAL;
+    }
+
+    if (fsmap.get_filesystem(fs_name)) {
+      auto fs = fsmap.get_filesystem(fs_name);
+      if (*(fs->mds_map.get_data_pools().begin()) == data
+          && fs->mds_map.get_metadata_pool() == metadata) {
+        // Identical FS created already, this is a no-op
+        ss << "filesystem '" << fs_name << "' already exists";
+        return 0;
+      } else {
+        ss << "filesystem already exists with name '" << fs_name << "'";
+        return -EINVAL;
+      }
+    }
+
+    bool force = false;
+    cmd_getval(cmdmap, "force", force);
+
+    const pool_stat_t *stat = mon->mgrstatmon()->get_pool_stat(metadata);
+    if (stat) {
+      int64_t metadata_num_objects = stat->stats.sum.num_objects;
+      if (!force && metadata_num_objects > 0) {
+	ss << "pool '" << metadata_name
+	   << "' already contains some objects. Use an empty pool instead.";
+	return -EINVAL;
+      }
+    }
+
+    if (fsmap.filesystem_count() > 0
+        && !fsmap.get_enable_multiple()) {
+      ss << "Creation of multiple filesystems is disabled.  To enable "
+            "this experimental feature, use 'ceph fs flag set enable_multiple "
+            "true'";
+      return -EINVAL;
+    }
+
+    for (auto& fs : fsmap.get_filesystems()) {
+      const std::vector<int64_t> &data_pools = fs->mds_map.get_data_pools();
+
+      bool sure = false;
+      cmd_getval(cmdmap,
+                 "allow_dangerous_metadata_overlay", sure);
+
+      if ((std::find(data_pools.begin(), data_pools.end(), data) != data_pools.end()
+	   || fs->mds_map.get_metadata_pool() == metadata)
+	  && !sure) {
+	ss << "Filesystem '" << fs_name
+	   << "' is already using one of the specified RADOS pools. This should ONLY be done in emergencies and after careful reading of the documentation. Pass --allow-dangerous-metadata-overlay to permit this.";
+	return -EEXIST;
+      }
+    }
+
+    int64_t fscid = FS_CLUSTER_ID_NONE;
+    if (cmd_getval(cmdmap, "fscid", fscid)) {
+      if (!force) {
+        ss << "Pass --force to create a file system with a specific ID";
+        return -EINVAL;
+      }
+      if (fsmap.filesystem_exists(fscid)) {
+        ss << "filesystem already exists with id '" << fscid << "'";
+        return -EINVAL;
+      }
+    }
+
+    pg_pool_t const *data_pool = mon->osdmon()->osdmap.get_pg_pool(data);
+    ceph_assert(data_pool != NULL);  // Checked it existed above
+    pg_pool_t const *metadata_pool = mon->osdmon()->osdmap.get_pg_pool(metadata);
+    ceph_assert(metadata_pool != NULL);  // Checked it existed above
+
+    int r = _check_pool(mon->osdmon()->osdmap, data, POOL_DATA_DEFAULT, force, &ss);
+    if (r < 0) {
+      return r;
+    }
+
+    r = _check_pool(mon->osdmon()->osdmap, metadata, POOL_METADATA, force, &ss);
+    if (r < 0) {
+      return r;
+    }
+    
+    if (!mon->osdmon()->is_writeable()) {
+      // not allowed to write yet, so retry when we can
+      mon->osdmon()->wait_for_writeable(op, new PaxosService::C_RetryMessage(mon->mdsmon(), op));
+      return -EAGAIN;
+    }
+    mon->osdmon()->do_application_enable(data,
+					 pg_pool_t::APPLICATION_NAME_CEPHFS,
+					 "data", fs_name, true);
+    mon->osdmon()->do_application_enable(metadata,
+					 pg_pool_t::APPLICATION_NAME_CEPHFS,
+					 "metadata", fs_name, true);
+    mon->osdmon()->do_set_pool_opt(metadata,
+				   pool_opts_t::RECOVERY_PRIORITY,
+				   static_cast<int64_t>(5));
+    mon->osdmon()->do_set_pool_opt(metadata,
+				   pool_opts_t::PG_NUM_MIN,
+				   static_cast<int64_t>(16));
+    mon->osdmon()->do_set_pool_opt(metadata,
+				   pool_opts_t::PG_AUTOSCALE_BIAS,
+				   static_cast<double>(4.0));
+    mon->osdmon()->propose_pending();
+
+    bool recover = false;
+    cmd_getval(cmdmap, "recover", recover);
+
+    // All checks passed, go ahead and create.
+    auto&& fs = fsmap.create_filesystem(fs_name, metadata, data,
+        mon->get_quorum_con_features(), fscid, recover);
+
+    ss << "new fs with metadata pool " << metadata << " and data pool " << data;
+
+    if (recover) {
+      return 0;
+    }
+
+    // assign a standby to rank 0 to avoid health warnings
+    auto info = fsmap.find_replacement_for({fs->fscid, 0});
+
+    if (info) {
+      mon->clog->info() << info->human_name() << " assigned to filesystem "
+          << fs_name << " as rank 0";
+      fsmap.promote(info->global_id, *fs, 0);
+    }
+
+    return 0;
+  }
+
+private:
+  Paxos *m_paxos;
+};
+
+class SetHandler : public FileSystemCommandHandler
+{
+public:
+  SetHandler()
+    : FileSystemCommandHandler("fs set")
+  {}
+
+  int handle(
+      Monitor *mon,
+      FSMap& fsmap,
+      MonOpRequestRef op,
+      const cmdmap_t& cmdmap,
+      std::ostream &ss) override
+  {
+    std::string fs_name;
+    if (!cmd_getval(cmdmap, "fs_name", fs_name) || fs_name.empty()) {
+      ss << "Missing filesystem name";
+      return -EINVAL;
+    }
+
+    auto fs = fsmap.get_filesystem(fs_name);
+    string var;
+    if (!cmd_getval(cmdmap, "var", var) || var.empty()) {
+      ss << "Invalid variable";
+      return -EINVAL;
+    }
+    string val;
+    string interr;
+    int64_t n = 0;
+    if (!cmd_getval(cmdmap, "val", val)) {
+      return -EINVAL;
+    }
+    // we got a string.  see if it contains an int.
+    n = strict_strtoll(val.c_str(), 10, &interr);
+    if (var == "max_mds") {
+      // NOTE: see also "mds set_max_mds", which can modify the same field.
+      if (interr.length()) {
+        ss << interr;
+	return -EINVAL;
+      }
+
+      if (n <= 0) {
+        ss << "You must specify at least one MDS";
+        return -EINVAL;
+      }
+
+      if (n > 1 && n > fs->mds_map.get_max_mds()) {
+	if (fs->mds_map.was_snaps_ever_allowed() &&
+	    !fs->mds_map.allows_multimds_snaps()) {
+	  ss << "multi-active MDS is not allowed while there are snapshots possibly created by pre-mimic MDS";
+	  return -EINVAL;
+	}
+      }
+      if (n > MAX_MDS) {
+        ss << "may not have more than " << MAX_MDS << " MDS ranks";
+        return -EINVAL;
+      }
+
+      fsmap.modify_filesystem(
+          fs->fscid,
+          [n](std::shared_ptr<Filesystem> fs)
+      {
+	fs->mds_map.clear_flag(CEPH_MDSMAP_NOT_JOINABLE);
+        fs->mds_map.set_max_mds(n);
+      });
+    } else if (var == "inline_data") {
+      bool enable_inline = false;
+      int r = parse_bool(val, &enable_inline, ss);
+      if (r != 0) {
+        return r;
+      }
+
+      if (enable_inline) {
+        bool confirm = false;
+        cmd_getval(cmdmap, "yes_i_really_really_mean_it", confirm);
+	if (!confirm) {
+	  ss << "Inline data support is deprecated and will be removed in a future release. "
+	     << "Add --yes-i-really-really-mean-it if you are certain you want this enabled.";
+	  return -EPERM;
+	}
+	ss << "inline data enabled";
+
+        fsmap.modify_filesystem(
+            fs->fscid,
+            [](std::shared_ptr<Filesystem> fs)
+        {
+          fs->mds_map.set_inline_data_enabled(true);
+        });
+      } else {
+	ss << "inline data disabled";
+        fsmap.modify_filesystem(
+            fs->fscid,
+            [](std::shared_ptr<Filesystem> fs)
+        {
+          fs->mds_map.set_inline_data_enabled(false);
+        });
+      }
+    } else if (var == "balancer") {
+      if (val.empty()) {
+        ss << "unsetting the metadata load balancer";
+      } else {
+        ss << "setting the metadata load balancer to " << val;
+      }
+      fsmap.modify_filesystem(
+	fs->fscid,
+	[val](std::shared_ptr<Filesystem> fs)
+        {
+          fs->mds_map.set_balancer(val);
+        });
+      return true;
+    } else if (var == "max_file_size") {
+      if (interr.length()) {
+	ss << var << " requires an integer value";
+	return -EINVAL;
+      }
+      if (n < CEPH_MIN_STRIPE_UNIT) {
+	ss << var << " must at least " << CEPH_MIN_STRIPE_UNIT;
+	return -ERANGE;
+      }
+      fsmap.modify_filesystem(
+          fs->fscid,
+          [n](std::shared_ptr<Filesystem> fs)
+      {
+        fs->mds_map.set_max_filesize(n);
+      });
+    } else if (var == "allow_new_snaps") {
+      bool enable_snaps = false;
+      int r = parse_bool(val, &enable_snaps, ss);
+      if (r != 0) {
+        return r;
+      }
+
+      if (!enable_snaps) {
+        fsmap.modify_filesystem(
+            fs->fscid,
+            [](std::shared_ptr<Filesystem> fs)
+        {
+          fs->mds_map.clear_snaps_allowed();
+        });
+	ss << "disabled new snapshots";
+      } else {
+        fsmap.modify_filesystem(
+            fs->fscid,
+            [](std::shared_ptr<Filesystem> fs)
+        {
+          fs->mds_map.set_snaps_allowed();
+        });
+	ss << "enabled new snapshots";
+      }
+    } else if (var == "allow_multimds") {
+        ss << "Multiple MDS is always enabled. Use the max_mds"
+           << " parameter to control the number of active MDSs"
+           << " allowed. This command is DEPRECATED and will be"
+           << " REMOVED from future releases.";
+    } else if (var == "allow_multimds_snaps") {
+      bool enable = false;
+      int r = parse_bool(val, &enable, ss);
+      if (r != 0) {
+        return r;
+      }
+
+      string confirm;
+      if (!cmd_getval(cmdmap, "confirm", confirm) ||
+	  confirm != "--yes-i-am-really-a-mds") {
+	ss << "Warning! This command is for MDS only. Do not run it manually";
+	return -EPERM;
+      }
+
+      if (enable) {
+	ss << "enabled multimds with snapshot";
+        fsmap.modify_filesystem(
+            fs->fscid,
+            [](std::shared_ptr<Filesystem> fs)
+        {
+	  fs->mds_map.set_multimds_snaps_allowed();
+        });
+      } else {
+	ss << "disabled multimds with snapshot";
+        fsmap.modify_filesystem(
+            fs->fscid,
+            [](std::shared_ptr<Filesystem> fs)
+        {
+	  fs->mds_map.clear_multimds_snaps_allowed();
+        });
+      }
+    } else if (var == "allow_dirfrags") {
+        ss << "Directory fragmentation is now permanently enabled."
+           << " This command is DEPRECATED and will be REMOVED from future releases.";
+    } else if (var == "down") {
+      bool is_down = false;
+      int r = parse_bool(val, &is_down, ss);
+      if (r != 0) {
+        return r;
+      }
+
+      ss << fs->mds_map.get_fs_name();
+
+      fsmap.modify_filesystem(
+          fs->fscid,
+          [is_down](std::shared_ptr<Filesystem> fs)
+      {
+	if (is_down) {
+          if (fs->mds_map.get_max_mds() > 0) {
+	    fs->mds_map.set_old_max_mds();
+	    fs->mds_map.set_max_mds(0);
+          } /* else already down! */
+	} else {
+	  mds_rank_t oldmax = fs->mds_map.get_old_max_mds();
+	  fs->mds_map.set_max_mds(oldmax ? oldmax : 1);
+	}
+      });
+
+      if (is_down) {
+	ss << " marked down. ";
+      } else {
+	ss << " marked up, max_mds = " << fs->mds_map.get_max_mds();
+      }
+    } else if (var == "cluster_down" || var == "joinable") {
+      bool joinable = true;
+      int r = parse_bool(val, &joinable, ss);
+      if (r != 0) {
+        return r;
+      }
+      if (var == "cluster_down") {
+        joinable = !joinable;
+      }
+
+      ss << fs->mds_map.get_fs_name();
+
+      fsmap.modify_filesystem(
+          fs->fscid,
+          [joinable](std::shared_ptr<Filesystem> fs)
+      {
+	if (joinable) {
+	  fs->mds_map.clear_flag(CEPH_MDSMAP_NOT_JOINABLE);
+	} else {
+	  fs->mds_map.set_flag(CEPH_MDSMAP_NOT_JOINABLE);
+	}
+      });
+
+      if (joinable) {
+	ss << " marked joinable; MDS may join as newly active.";
+      } else {
+	ss << " marked not joinable; MDS cannot join as newly active.";
+      }
+
+      if (var == "cluster_down") {
+        ss << " WARNING: cluster_down flag is deprecated and will be"
+           << " removed in a future version. Please use \"joinable\".";
+      }
+    } else if (var == "standby_count_wanted") {
+      if (interr.length()) {
+       ss << var << " requires an integer value";
+       return -EINVAL;
+      }
+      if (n < 0) {
+       ss << var << " must be non-negative";
+       return -ERANGE;
+      }
+      fsmap.modify_filesystem(
+          fs->fscid,
+          [n](std::shared_ptr<Filesystem> fs)
+      {
+        fs->mds_map.set_standby_count_wanted(n);
+      });
+    } else if (var == "session_timeout") {
+      if (interr.length()) {
+       ss << var << " requires an integer value";
+       return -EINVAL;
+      }
+      if (n < 30) {
+       ss << var << " must be at least 30s";
+       return -ERANGE;
+      }
+      fsmap.modify_filesystem(
+          fs->fscid,
+          [n](std::shared_ptr<Filesystem> fs)
+      {
+        fs->mds_map.set_session_timeout((uint32_t)n);
+      });
+    } else if (var == "session_autoclose") {
+      if (interr.length()) {
+       ss << var << " requires an integer value";
+       return -EINVAL;
+      }
+      if (n < 30) {
+       ss << var << " must be at least 30s";
+       return -ERANGE;
+      }
+      fsmap.modify_filesystem(
+          fs->fscid,
+          [n](std::shared_ptr<Filesystem> fs)
+      {
+        fs->mds_map.set_session_autoclose((uint32_t)n);
+      });
+    } else if (var == "allow_standby_replay") {
+      bool allow = false;
+      int r = parse_bool(val, &allow, ss);
+      if (r != 0) {
+        return r;
+      }
+
+      if (!allow) {
+        if (!mon->osdmon()->is_writeable()) {
+          // not allowed to write yet, so retry when we can
+          mon->osdmon()->wait_for_writeable(op, new PaxosService::C_RetryMessage(mon->mdsmon(), op));
+          return -EAGAIN;
+        }
+        std::vector<mds_gid_t> to_fail;
+        for (const auto& [gid, info]: fs->mds_map.get_mds_info()) {
+          if (info.state == MDSMap::STATE_STANDBY_REPLAY) {
+            to_fail.push_back(gid);
+          }
+        }
+
+        for (const auto& gid : to_fail) {
+          mon->mdsmon()->fail_mds_gid(fsmap, gid);
+        }
+        if (!to_fail.empty()) {
+          mon->osdmon()->propose_pending();
+        }
+      }
+
+      auto f = [allow](auto& fs) {
+        if (allow) {
+          fs->mds_map.set_standby_replay_allowed();
+        } else {
+          fs->mds_map.clear_standby_replay_allowed();
+        }
+      };
+      fsmap.modify_filesystem(fs->fscid, std::move(f));
+    } else if (var == "min_compat_client") {
+      auto vno = ceph_release_from_name(val.c_str());
+      if (!vno) {
+	ss << "version " << val << " is not recognized";
+	return -EINVAL;
+      }
+      ss << "WARNING: setting min_compat_client is deprecated"
+            " and may not do what you want.\n"
+            "The oldest release to set is octopus.\n"
+            "Please migrate to `ceph fs required_client_features ...`.";
+      auto f = [vno](auto&& fs) {
+        fs->mds_map.set_min_compat_client(vno);
+      };
+      fsmap.modify_filesystem(fs->fscid, std::move(f));
+    } else {
+      ss << "unknown variable " << var;
+      return -EINVAL;
+    }
+
+    return 0;
+  }
+};
+
+class CompatSetHandler : public FileSystemCommandHandler
+{
+  public:
+    CompatSetHandler()
+      : FileSystemCommandHandler("fs compat")
+    {
+    }
+
+    int handle(
+	Monitor *mon,
+	FSMap &fsmap,
+	MonOpRequestRef op,
+	const cmdmap_t& cmdmap,
+	std::ostream &ss) override
+    {
+      static const std::set<std::string> subops = {"rm_incompat", "rm_compat", "add_incompat", "add_compat"};
+
+      std::string fs_name;
+      if (!cmd_getval(cmdmap, "fs_name", fs_name) || fs_name.empty()) {
+	ss << "Missing filesystem name";
+	return -EINVAL;
+      }
+      auto fs = fsmap.get_filesystem(fs_name);
+      if (fs == nullptr) {
+	ss << "Not found: '" << fs_name << "'";
+	return -ENOENT;
+      }
+
+      string subop;
+      if (!cmd_getval(cmdmap, "subop", subop) || subops.count(subop) == 0) {
+	ss << "subop `" << subop << "' not recognized. Must be one of: " << subops;
+	return -EINVAL;
+      }
+
+      int64_t feature;
+      if (!cmd_getval(cmdmap, "feature", feature) || feature <= 0) {
+        ss << "Invalid feature";
+        return -EINVAL;
+      }
+
+      if (fs->mds_map.get_num_up_mds() > 0) {
+        ss << "file system must be failed or down; use `ceph fs fail` to bring down";
+        return -EBUSY;
+      }
+
+      CompatSet cs = fs->mds_map.compat;
+      if (subop == "rm_compat") {
+        if (cs.compat.contains(feature)) {
+          ss << "removed compat feature " << feature;
+          cs.compat.remove(feature);
+        } else {
+          ss << "already removed compat feature " << feature;
+        }
+      } else if (subop == "rm_incompat") {
+        if (cs.incompat.contains(feature)) {
+          ss << "removed incompat feature " << feature;
+          cs.incompat.remove(feature);
+        } else {
+          ss << "already removed incompat feature " << feature;
+        }
+      } else if (subop == "add_compat" || subop == "add_incompat") {
+        string feature_str;
+        if (!cmd_getval(cmdmap, "feature_str", feature_str) || feature_str.empty()) {
+          ss << "adding a feature requires a feature string";
+          return -EINVAL;
+        }
+        auto f = CompatSet::Feature(feature, feature_str);
+        if (subop == "add_compat") {
+          if (cs.compat.contains(feature)) {
+            auto name = cs.compat.get_name(feature);
+            if (name == feature_str) {
+              ss << "feature already exists";
+            } else {
+              ss << "feature with differing name `" << name << "' exists";
+              return -EEXIST;
+            }
+          } else {
+            cs.compat.insert(f);
+            ss << "added compat feature " << f;
+          }
+        } else if (subop == "add_incompat") {
+          if (cs.incompat.contains(feature)) {
+            auto name = cs.incompat.get_name(feature);
+            if (name == feature_str) {
+              ss << "feature already exists";
+            } else {
+              ss << "feature with differing name `" << name << "' exists";
+              return -EEXIST;
+            }
+          } else {
+            cs.incompat.insert(f);
+            ss << "added incompat feature " << f;
+          }
+        } else ceph_assert(0);
+      } else ceph_assert(0);
+
+      auto modifyf = [cs = std::move(cs)](auto&& fs) {
+        fs->mds_map.compat = cs;
+      };
+
+      fsmap.modify_filesystem(fs->fscid, std::move(modifyf));
+      return 0;
+    }
+};
+
+class RequiredClientFeaturesHandler : public FileSystemCommandHandler
+{
+  public:
+    RequiredClientFeaturesHandler()
+      : FileSystemCommandHandler("fs required_client_features")
+    {
+    }
+
+    int handle(
+	Monitor *mon,
+	FSMap &fsmap,
+	MonOpRequestRef op,
+	const cmdmap_t& cmdmap,
+	std::ostream &ss) override
+    {
+      std::string fs_name;
+      if (!cmd_getval(cmdmap, "fs_name", fs_name) || fs_name.empty()) {
+	ss << "Missing filesystem name";
+	return -EINVAL;
+      }
+      auto fs = fsmap.get_filesystem(fs_name);
+      if (fs == nullptr) {
+	ss << "Not found: '" << fs_name << "'";
+	return -ENOENT;
+      }
+      string subop;
+      if (!cmd_getval(cmdmap, "subop", subop) ||
+	  (subop != "add" && subop != "rm")) {
+	ss << "Must either add or rm a feature; " << subop << " is not recognized";
+	return -EINVAL;
+      }
+      string val;
+      if (!cmd_getval(cmdmap, "val", val) || val.empty()) {
+	ss << "Missing feature id/name";
+	return -EINVAL;
+      }
+
+      int feature = cephfs_feature_from_name(val);
+      if (feature < 0) {
+	string err;
+	feature = strict_strtol(val.c_str(), 10, &err);
+	if (err.length()) {
+	  ss << "Invalid feature name: " << val;
+	  return -EINVAL;
+	}
+	if (feature < 0 || feature > CEPHFS_FEATURE_MAX) {
+	  ss << "Invalid feature id: " << feature;
+	  return -EINVAL;
+	}
+      }
+
+      if (subop == "add") {
+	bool ret = false;
+	fsmap.modify_filesystem(
+	    fs->fscid,
+	    [feature, &ret](auto&& fs)
+	{
+	  if (fs->mds_map.get_required_client_features().test(feature))
+	    return;
+	  fs->mds_map.add_required_client_feature(feature);
+	  ret = true;
+	});
+	if (ret) {
+	  ss << "added feature '" << cephfs_feature_name(feature) << "' to required_client_features";
+	} else {
+	  ss << "feature '" << cephfs_feature_name(feature) << "' is already set";
+	}
+      } else {
+	bool ret = false;
+	fsmap.modify_filesystem(
+	    fs->fscid,
+	    [feature, &ret](auto&& fs)
+	{
+          if (!fs->mds_map.get_required_client_features().test(feature))
+            return;
+          fs->mds_map.remove_required_client_feature(feature);
+          ret = true;
+	});
+	if (ret) {
+	  ss << "removed feature '" << cephfs_feature_name(feature) << "' from required_client_features";
+	} else {
+	  ss << "feature '" << cephfs_feature_name(feature) << "' is already unset";
+	}
+      }
+      return 0;
+   }
+};
+
+
+class AddDataPoolHandler : public FileSystemCommandHandler
+{
+  public:
+  explicit AddDataPoolHandler(Paxos *paxos)
+    : FileSystemCommandHandler("fs add_data_pool"), m_paxos(paxos)
+  {}
+
+  bool batched_propose() override {
+    return true;
+  }
+
+  int handle(
+      Monitor *mon,
+      FSMap& fsmap,
+      MonOpRequestRef op,
+      const cmdmap_t& cmdmap,
+      std::ostream &ss) override
+  {
+    ceph_assert(m_paxos->is_plugged());
+
+    string poolname;
+    cmd_getval(cmdmap, "pool", poolname);
+
+    std::string fs_name;
+    if (!cmd_getval(cmdmap, "fs_name", fs_name)
+        || fs_name.empty()) {
+      ss << "Missing filesystem name";
+      return -EINVAL;
+    }
+
+    int64_t poolid = mon->osdmon()->osdmap.lookup_pg_pool_name(poolname);
+    if (poolid < 0) {
+      string err;
+      poolid = strict_strtol(poolname.c_str(), 10, &err);
+      if (err.length()) {
+	ss << "pool '" << poolname << "' does not exist";
+	return -ENOENT;
+      }
+    }
+
+    int r = _check_pool(mon->osdmon()->osdmap, poolid, POOL_DATA_EXTRA, false, &ss);
+    if (r != 0) {
+      return r;
+    }
+
+    auto fs = fsmap.get_filesystem(fs_name);
+    // no-op when the data_pool already on fs
+    if (fs->mds_map.is_data_pool(poolid)) {
+      ss << "data pool " << poolid << " is already on fs " << fs_name;
+      return 0;
+    }
+
+    if (!mon->osdmon()->is_writeable()) {
+      // not allowed to write yet, so retry when we can
+      mon->osdmon()->wait_for_writeable(op, new PaxosService::C_RetryMessage(mon->mdsmon(), op));
+      return -EAGAIN;
+    }
+    mon->osdmon()->do_application_enable(poolid,
+					 pg_pool_t::APPLICATION_NAME_CEPHFS,
+					 "data", fs_name, true);
+    mon->osdmon()->propose_pending();
+
+    fsmap.modify_filesystem(
+        fs->fscid,
+        [poolid](std::shared_ptr<Filesystem> fs)
+    {
+      fs->mds_map.add_data_pool(poolid);
+    });
+
+    ss << "added data pool " << poolid << " to fsmap";
+
+    return 0;
+  }
+
+private:
+  Paxos *m_paxos;
+};
+
+class SetDefaultHandler : public FileSystemCommandHandler
+{
+  public:
+  SetDefaultHandler()
+    : FileSystemCommandHandler("fs set-default")
+  {}
+
+  int handle(
+      Monitor *mon,
+      FSMap& fsmap,
+      MonOpRequestRef op,
+      const cmdmap_t& cmdmap,
+      std::ostream &ss) override
+  {
+    std::string fs_name;
+    cmd_getval(cmdmap, "fs_name", fs_name);
+    auto fs = fsmap.get_filesystem(fs_name);
+    if (fs == nullptr) {
+        ss << "filesystem '" << fs_name << "' does not exist";
+        return -ENOENT;
+    }
+
+    fsmap.set_legacy_client_fscid(fs->fscid);
+    return 0;
+  }
+};
+
+class RemoveFilesystemHandler : public FileSystemCommandHandler
+{
+  public:
+  RemoveFilesystemHandler()
+    : FileSystemCommandHandler("fs rm")
+  {}
+
+  int handle(
+      Monitor *mon,
+      FSMap& fsmap,
+      MonOpRequestRef op,
+      const cmdmap_t& cmdmap,
+      std::ostream &ss) override
+  {
+    /* We may need to blocklist ranks. */
+    if (!mon->osdmon()->is_writeable()) {
+      // not allowed to write yet, so retry when we can
+      mon->osdmon()->wait_for_writeable(op, new PaxosService::C_RetryMessage(mon->mdsmon(), op));
+      return -EAGAIN;
+    }
+
+    // Check caller has correctly named the FS to delete
+    // (redundant while there is only one FS, but command
+    //  syntax should apply to multi-FS future)
+    string fs_name;
+    cmd_getval(cmdmap, "fs_name", fs_name);
+    auto fs = fsmap.get_filesystem(fs_name);
+    if (fs == nullptr) {
+        // Consider absence success to make deletes idempotent
+        ss << "filesystem '" << fs_name << "' does not exist";
+        return 0;
+    }
+
+    // Check that no MDS daemons are active
+    if (fs->mds_map.get_num_up_mds() > 0) {
+      ss << "all MDS daemons must be inactive/failed before removing filesystem. See `ceph fs fail`.";
+      return -EINVAL;
+    }
+
+    // Check for confirmation flag
+    bool sure = false;
+    cmd_getval(cmdmap, "yes_i_really_mean_it", sure);
+    if (!sure) {
+      ss << "this is a DESTRUCTIVE operation and will make data in your filesystem permanently" \
+            " inaccessible.  Add --yes-i-really-mean-it if you are sure you wish to continue.";
+      return -EPERM;
+    }
+
+    if (fsmap.get_legacy_client_fscid() == fs->fscid) {
+      fsmap.set_legacy_client_fscid(FS_CLUSTER_ID_NONE);
+    }
+
+    std::vector<mds_gid_t> to_fail;
+    // There may be standby_replay daemons left here
+    for (const auto &i : fs->mds_map.get_mds_info()) {
+      ceph_assert(i.second.state == MDSMap::STATE_STANDBY_REPLAY);
+      to_fail.push_back(i.first);
+    }
+
+    for (const auto &gid : to_fail) {
+      // Standby replays don't write, so it isn't important to
+      // wait for an osdmap propose here: ignore return value.
+      mon->mdsmon()->fail_mds_gid(fsmap, gid);
+    }
+    if (!to_fail.empty()) {
+      mon->osdmon()->propose_pending(); /* maybe new blocklists */
+    }
+
+    fsmap.erase_filesystem(fs->fscid);
+
+    return 0;
+  }
+};
+
+class ResetFilesystemHandler : public FileSystemCommandHandler
+{
+  public:
+  ResetFilesystemHandler()
+    : FileSystemCommandHandler("fs reset")
+  {}
+
+  int handle(
+      Monitor *mon,
+      FSMap& fsmap,
+      MonOpRequestRef op,
+      const cmdmap_t& cmdmap,
+      std::ostream &ss) override
+  {
+    string fs_name;
+    cmd_getval(cmdmap, "fs_name", fs_name);
+    auto fs = fsmap.get_filesystem(fs_name);
+    if (fs == nullptr) {
+        ss << "filesystem '" << fs_name << "' does not exist";
+        // Unlike fs rm, we consider this case an error
+        return -ENOENT;
+    }
+
+    // Check that no MDS daemons are active
+    if (fs->mds_map.get_num_up_mds() > 0) {
+      ss << "all MDS daemons must be inactive before resetting filesystem: set the cluster_down flag"
+            " and use `ceph mds fail` to make this so";
+      return -EINVAL;
+    }
+
+    // Check for confirmation flag
+    bool sure = false;
+    cmd_getval(cmdmap, "yes_i_really_mean_it", sure);
+    if (!sure) {
+      ss << "this is a potentially destructive operation, only for use by experts in disaster recovery.  "
+        "Add --yes-i-really-mean-it if you are sure you wish to continue.";
+      return -EPERM;
+    }
+
+    fsmap.reset_filesystem(fs->fscid);
+
+    return 0;
+  }
+};
+
+class RemoveDataPoolHandler : public FileSystemCommandHandler
+{
+  public:
+  RemoveDataPoolHandler()
+    : FileSystemCommandHandler("fs rm_data_pool")
+  {}
+
+  int handle(
+      Monitor *mon,
+      FSMap& fsmap,
+      MonOpRequestRef op,
+      const cmdmap_t& cmdmap,
+      std::ostream &ss) override
+  {
+    string poolname;
+    cmd_getval(cmdmap, "pool", poolname);
+
+    std::string fs_name;
+    if (!cmd_getval(cmdmap, "fs_name", fs_name)
+        || fs_name.empty()) {
+      ss << "Missing filesystem name";
+      return -EINVAL;
+    }
+
+    int64_t poolid = mon->osdmon()->osdmap.lookup_pg_pool_name(poolname);
+    if (poolid < 0) {
+      string err;
+      poolid = strict_strtol(poolname.c_str(), 10, &err);
+      if (err.length()) {
+	ss << "pool '" << poolname << "' does not exist";
+        return -ENOENT;
+      } else if (poolid < 0) {
+        ss << "invalid pool id '" << poolid << "'";
+        return -EINVAL;
+      }
+    }
+
+    ceph_assert(poolid >= 0);  // Checked by parsing code above
+
+    auto fs = fsmap.get_filesystem(fs_name);
+    if (fs->mds_map.get_first_data_pool() == poolid) {
+      ss << "cannot remove default data pool";
+      return -EINVAL;
+    }
+
+    int r = 0;
+    fsmap.modify_filesystem(fs->fscid,
+        [&r, poolid](std::shared_ptr<Filesystem> fs)
+    {
+      r = fs->mds_map.remove_data_pool(poolid);
+    });
+    if (r == -ENOENT) {
+      // It was already removed, succeed in silence
+      return 0;
+    } else if (r == 0) {
+      // We removed it, succeed
+      ss << "removed data pool " << poolid << " from fsmap";
+      return 0;
+    } else {
+      // Unexpected error, bubble up
+      return r;
+    }
+  }
+};
+
+/**
+ * For commands with an alternative prefix
+ */
+template<typename T>
+class AliasHandler : public T
+{
+  std::string alias_prefix;
+
+  public:
+  explicit AliasHandler(const std::string &new_prefix)
+    : T()
+  {
+    alias_prefix = new_prefix;
+  }
+
+  std::string const &get_prefix() const override {return alias_prefix;}
+
+  int handle(
+      Monitor *mon,
+      FSMap& fsmap,
+      MonOpRequestRef op,
+      const cmdmap_t& cmdmap,
+      std::ostream &ss) override
+  {
+    return T::handle(mon, fsmap, op, cmdmap, ss);
+  }
+};
+
+class MirrorHandlerEnable : public FileSystemCommandHandler
+{
+public:
+  MirrorHandlerEnable()
+    : FileSystemCommandHandler("fs mirror enable")
+  {}
+
+  int handle(Monitor *mon,
+             FSMap &fsmap, MonOpRequestRef op,
+             const cmdmap_t& cmdmap, std::ostream &ss) override {
+    std::string fs_name;
+    if (!cmd_getval(cmdmap, "fs_name", fs_name) || fs_name.empty()) {
+      ss << "Missing filesystem name";
+      return -EINVAL;
+    }
+
+    auto fs = fsmap.get_filesystem(fs_name);
+    if (fs == nullptr) {
+      ss << "Filesystem '" << fs_name << "' not found";
+      return -ENOENT;
+    }
+
+    if (fs->mirror_info.is_mirrored()) {
+      return 0;
+    }
+
+    auto f = [](auto &&fs) {
+               fs->mirror_info.enable_mirroring();
+    };
+    fsmap.modify_filesystem(fs->fscid, std::move(f));
+
+    return 0;
+  }
+};
+
+class MirrorHandlerDisable : public FileSystemCommandHandler
+{
+public:
+  MirrorHandlerDisable()
+    : FileSystemCommandHandler("fs mirror disable")
+  {}
+
+  int handle(Monitor *mon,
+             FSMap &fsmap, MonOpRequestRef op,
+             const cmdmap_t& cmdmap, std::ostream &ss) override {
+    std::string fs_name;
+    if (!cmd_getval(cmdmap, "fs_name", fs_name) || fs_name.empty()) {
+      ss << "Missing filesystem name";
+      return -EINVAL;
+    }
+
+    auto fs = fsmap.get_filesystem(fs_name);
+    if (fs == nullptr) {
+      ss << "Filesystem '" << fs_name << "' not found";
+      return -ENOENT;
+    }
+
+    if (!fs->mirror_info.is_mirrored()) {
+      return 0;
+    }
+
+    auto f = [](auto &&fs) {
+      fs->mirror_info.disable_mirroring();
+    };
+    fsmap.modify_filesystem(fs->fscid, std::move(f));
+
+    return 0;
+  }
+};
+
+class MirrorHandlerAddPeer : public FileSystemCommandHandler
+{
+public:
+  MirrorHandlerAddPeer()
+    : FileSystemCommandHandler("fs mirror peer_add")
+  {}
+
+  boost::optional<std::pair<string, string>>
+  extract_remote_cluster_conf(const std::string &spec) {
+    auto pos = spec.find("@");
+    if (pos == std::string_view::npos) {
+      return boost::optional<std::pair<string, string>>();
+    }
+
+    auto client = spec.substr(0, pos);
+    auto cluster = spec.substr(pos+1);
+
+    return std::make_pair(client, cluster);
+  }
+
+  bool peer_add(FSMap &fsmap, Filesystem::const_ref &&fs,
+                const cmdmap_t &cmdmap, std::ostream &ss) {
+    string peer_uuid;
+    string remote_spec;
+    string remote_fs_name;
+    cmd_getval(cmdmap, "uuid", peer_uuid);
+    cmd_getval(cmdmap, "remote_cluster_spec", remote_spec);
+    cmd_getval(cmdmap, "remote_fs_name", remote_fs_name);
+
+    // verify (and extract) remote cluster specification
+    auto remote_conf = extract_remote_cluster_conf(remote_spec);
+    if (!remote_conf) {
+      ss << "invalid remote cluster spec -- should be <client>@<cluster>";
+      return false;
+    }
+
+    if (fs->mirror_info.has_peer(peer_uuid)) {
+      ss << "peer already exists";
+      return true;
+    }
+    if (fs->mirror_info.has_peer((*remote_conf).first, (*remote_conf).second,
+                                 remote_fs_name)) {
+      ss << "peer already exists";
+      return true;
+    }
+
+    auto f = [peer_uuid, remote_conf, remote_fs_name](auto &&fs) {
+               fs->mirror_info.peer_add(peer_uuid, (*remote_conf).first,
+                                        (*remote_conf).second, remote_fs_name);
+             };
+    fsmap.modify_filesystem(fs->fscid, std::move(f));
+    return true;
+  }
+
+  int handle(Monitor *mon,
+             FSMap &fsmap, MonOpRequestRef op,
+             const cmdmap_t& cmdmap, std::ostream &ss) override {
+    std::string fs_name;
+    if (!cmd_getval(cmdmap, "fs_name", fs_name) || fs_name.empty()) {
+      ss << "Missing filesystem name";
+      return -EINVAL;
+    }
+
+    auto fs = fsmap.get_filesystem(fs_name);
+    if (fs == nullptr) {
+      ss << "Filesystem '" << fs_name << "' not found";
+      return -ENOENT;
+    }
+
+    if (!fs->mirror_info.is_mirrored()) {
+      ss << "Mirroring not enabled for filesystem '" << fs_name << "'";
+      return -EINVAL;
+    }
+
+    auto res = peer_add(fsmap, std::move(fs), cmdmap, ss);
+    if (!res) {
+      return -EINVAL;
+    }
+
+    return 0;
+  }
+};
+
+class MirrorHandlerRemovePeer : public FileSystemCommandHandler
+{
+public:
+  MirrorHandlerRemovePeer()
+    : FileSystemCommandHandler("fs mirror peer_remove")
+  {}
+
+  bool peer_remove(FSMap &fsmap, Filesystem::const_ref &&fs,
+                   const cmdmap_t &cmdmap, std::ostream &ss) {
+    string peer_uuid;
+    cmd_getval(cmdmap, "uuid", peer_uuid);
+
+    if (!fs->mirror_info.has_peer(peer_uuid)) {
+      ss << "cannot find peer with uuid: " << peer_uuid;
+      return true;
+    }
+
+    auto f = [peer_uuid](auto &&fs) {
+               fs->mirror_info.peer_remove(peer_uuid);
+             };
+    fsmap.modify_filesystem(fs->fscid, std::move(f));
+    return true;
+  }
+
+  int handle(Monitor *mon,
+             FSMap &fsmap, MonOpRequestRef op,
+             const cmdmap_t& cmdmap, std::ostream &ss) override {
+    std::string fs_name;
+    if (!cmd_getval(cmdmap, "fs_name", fs_name) || fs_name.empty()) {
+      ss << "Missing filesystem name";
+      return -EINVAL;
+    }
+
+    auto fs = fsmap.get_filesystem(fs_name);
+    if (fs == nullptr) {
+      ss << "Filesystem '" << fs_name << "' not found";
+      return -ENOENT;
+    }
+
+    if (!fs->mirror_info.is_mirrored()) {
+      ss << "Mirroring not enabled for filesystem '" << fs_name << "'";
+      return -EINVAL;
+    }
+
+    auto res = peer_remove(fsmap, std::move(fs), cmdmap, ss);
+    if (!res) {
+      return -EINVAL;
+    }
+
+    return 0;
+  }
+};
+
+std::list<std::shared_ptr<FileSystemCommandHandler> >
+FileSystemCommandHandler::load(Paxos *paxos)
+{
+  std::list<std::shared_ptr<FileSystemCommandHandler> > handlers;
+
+  handlers.push_back(std::make_shared<SetHandler>());
+  handlers.push_back(std::make_shared<FailHandler>());
+  handlers.push_back(std::make_shared<FlagSetHandler>());
+  handlers.push_back(std::make_shared<CompatSetHandler>());
+  handlers.push_back(std::make_shared<RequiredClientFeaturesHandler>());
+  handlers.push_back(std::make_shared<AddDataPoolHandler>(paxos));
+  handlers.push_back(std::make_shared<RemoveDataPoolHandler>());
+  handlers.push_back(std::make_shared<FsNewHandler>(paxos));
+  handlers.push_back(std::make_shared<RemoveFilesystemHandler>());
+  handlers.push_back(std::make_shared<ResetFilesystemHandler>());
+
+  handlers.push_back(std::make_shared<SetDefaultHandler>());
+  handlers.push_back(std::make_shared<AliasHandler<SetDefaultHandler> >(
+        "fs set_default"));
+  handlers.push_back(std::make_shared<MirrorHandlerEnable>());
+  handlers.push_back(std::make_shared<MirrorHandlerDisable>());
+  handlers.push_back(std::make_shared<MirrorHandlerAddPeer>());
+  handlers.push_back(std::make_shared<MirrorHandlerRemovePeer>());
+
+  return handlers;
+}
+
+int FileSystemCommandHandler::_check_pool(
+    OSDMap &osd_map,
+    const int64_t pool_id,
+    int type,
+    bool force,
+    std::ostream *ss) const
+{
+  ceph_assert(ss != NULL);
+
+  const pg_pool_t *pool = osd_map.get_pg_pool(pool_id);
+  if (!pool) {
+    *ss << "pool id '" << pool_id << "' does not exist";
+    return -ENOENT;
+  }
+
+  const string& pool_name = osd_map.get_pool_name(pool_id);
+
+  if (pool->is_erasure()) {
+    if (type == POOL_METADATA) {
+      *ss << "pool '" << pool_name << "' (id '" << pool_id << "')"
+         << " is an erasure-coded pool.  Use of erasure-coded pools"
+         << " for CephFS metadata is not permitted";
+      return -EINVAL;
+    } else if (type == POOL_DATA_DEFAULT && !force) {
+      *ss << "pool '" << pool_name << "' (id '" << pool_id << "')"
+             " is an erasure-coded pool."
+             " Use of an EC pool for the default data pool is discouraged;"
+             " see the online CephFS documentation for more information."
+             " Use --force to override.";
+      return -EINVAL;
+    } else if (!pool->allows_ecoverwrites()) {
+      // non-overwriteable EC pools are only acceptable with a cache tier overlay
+      if (!pool->has_tiers() || !pool->has_read_tier() || !pool->has_write_tier()) {
+        *ss << "pool '" << pool_name << "' (id '" << pool_id << "')"
+            << " is an erasure-coded pool, with no overwrite support";
+        return -EINVAL;
+      }
+
+      // That cache tier overlay must be writeback, not readonly (it's the
+      // write operations like modify+truncate we care about support for)
+      const pg_pool_t *write_tier = osd_map.get_pg_pool(
+          pool->write_tier);
+      ceph_assert(write_tier != NULL);  // OSDMonitor shouldn't allow DNE tier
+      if (write_tier->cache_mode == pg_pool_t::CACHEMODE_FORWARD
+          || write_tier->cache_mode == pg_pool_t::CACHEMODE_READONLY) {
+        *ss << "EC pool '" << pool_name << "' has a write tier ("
+            << osd_map.get_pool_name(pool->write_tier)
+            << ") that is configured "
+               "to forward writes.  Use a cache mode such as 'writeback' for "
+               "CephFS";
+        return -EINVAL;
+      }
+    }
+  }
+
+  if (pool->is_tier()) {
+    *ss << " pool '" << pool_name << "' (id '" << pool_id
+      << "') is already in use as a cache tier.";
+    return -EINVAL;
+  }
+
+  if (!force && !pool->application_metadata.empty() &&
+      pool->application_metadata.count(
+        pg_pool_t::APPLICATION_NAME_CEPHFS) == 0) {
+    *ss << " pool '" << pool_name << "' (id '" << pool_id
+        << "') has a non-CephFS application enabled.";
+    return -EINVAL;
+  }
+
+  // Nothing special about this pool, so it is permissible
+  return 0;
+}
+
+int FileSystemCommandHandler::is_op_allowed(
+    const MonOpRequestRef& op, const FSMap& fsmap, const cmdmap_t& cmdmap,
+    std::ostream &ss) const
+{
+    string fs_name;
+    cmd_getval(cmdmap, "fs_name", fs_name);
+
+    // so that fsmap can filtered and the original copy is untouched.
+    FSMap fsmap_copy = fsmap;
+    fsmap_copy.filter(op->get_session()->get_allowed_fs_names());
+
+    auto fs = fsmap_copy.get_filesystem(fs_name);
+    if (fs == nullptr) {
+      /* let "fs rm" handle idempotent case where file system does not exist */
+      if (!(get_prefix() == "fs rm" && fsmap.get_filesystem(fs_name) == nullptr)) {
+        ss << "Filesystem not found: '" << fs_name << "'";
+        return -ENOENT;
+      }
+    }
+
+    if (!op->get_session()->fs_name_capable(fs_name, MON_CAP_W)) {
+      ss << "Permission denied: '" << fs_name << "'";
+      return -EPERM;
+    }
+
+  return 1;
+}