Adding upstream version 14.2.21.upstream/14.2.21upstream

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

1 files changed, 1564 insertions, 0 deletions

diff --git a/src/common/config.cc b/src/common/config.cc
new file mode 100644
index 00000000..863525ef
--- /dev/null
+++ b/src/common/config.cc
@@ -0,0 +1,1564 @@
+// -*- 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 <boost/type_traits.hpp>
+
+#include "common/ceph_argparse.h"
+#include "common/common_init.h"
+#include "common/config.h"
+#include "common/config_obs.h"
+#include "include/str_list.h"
+#include "include/stringify.h"
+#include "osd/osd_types.h"
+#include "common/errno.h"
+#include "common/hostname.h"
+#include "common/dout.h"
+
+/* Don't use standard Ceph logging in this file.
+ * We can't use logging until it's initialized, and a lot of the necessary
+ * initialization happens here.
+ */
+#undef dout
+#undef pdout
+#undef derr
+#undef generic_dout
+
+// set set_mon_vals()
+#define dout_subsys ceph_subsys_monc
+
+using std::map;
+using std::list;
+using std::ostringstream;
+using std::pair;
+using std::string;
+
+static const char *CEPH_CONF_FILE_DEFAULT = "$data_dir/config, /etc/ceph/$cluster.conf, $home/.ceph/$cluster.conf, $cluster.conf"
+#if defined(__FreeBSD__)
+    ", /usr/local/etc/ceph/$cluster.conf"
+#endif
+    ;
+
+#define _STR(x) #x
+#define STRINGIFY(x) _STR(x)
+
+const char *ceph_conf_level_name(int level)
+{
+  switch (level) {
+  case CONF_DEFAULT: return "default";   // built-in default
+  case CONF_MON: return "mon";           // monitor config database
+  case CONF_ENV: return "env";           // process environment (CEPH_ARGS)
+  case CONF_FILE: return "file";         // ceph.conf file
+  case CONF_CMDLINE: return "cmdline";   // process command line args
+  case CONF_OVERRIDE: return "override"; // injectargs or 'config set' at runtime
+  case CONF_FINAL: return "final";
+  default: return "???";
+  }
+}
+
+int ceph_resolve_file_search(const std::string& filename_list,
+			     std::string& result)
+{
+  list<string> ls;
+  get_str_list(filename_list, ls);
+
+  int ret = -ENOENT;
+  list<string>::iterator iter;
+  for (iter = ls.begin(); iter != ls.end(); ++iter) {
+    int fd = ::open(iter->c_str(), O_RDONLY|O_CLOEXEC);
+    if (fd < 0) {
+      ret = -errno;
+      continue;
+    }
+    close(fd);
+    result = *iter;
+    return 0;
+  }
+
+  return ret;
+}
+
+static int conf_stringify(const Option::value_t& v, string *out)
+{
+  if (boost::get<boost::blank>(&v)) {
+    return -ENOENT;
+  }
+  *out = Option::to_str(v);
+  return 0;
+}
+
+md_config_t::md_config_t(ConfigValues& values,
+			 const ConfigTracker& tracker,
+			 bool is_daemon)
+  : is_daemon(is_daemon)
+{
+  // Load the compile-time list of Option into
+  // a map so that we can resolve keys quickly.
+  for (const auto &i : ceph_options) {
+    if (schema.count(i.name)) {
+      // We may be instantiated pre-logging so send 
+      std::cerr << "Duplicate config key in schema: '" << i.name << "'"
+                << std::endl;
+      ceph_abort();
+    }
+    schema.emplace(std::piecewise_construct,
+		   std::forward_as_tuple(i.name),
+		   std::forward_as_tuple(i));
+  }
+
+  // Define the debug_* options as well.
+  subsys_options.reserve(values.subsys.get_num());
+  for (unsigned i = 0; i < values.subsys.get_num(); ++i) {
+    string name = string("debug_") + values.subsys.get_name(i);
+    subsys_options.push_back(
+      Option(name, Option::TYPE_STR, Option::LEVEL_ADVANCED));
+    Option& opt = subsys_options.back();
+    opt.set_default(stringify(values.subsys.get_log_level(i)) + "/" +
+		    stringify(values.subsys.get_gather_level(i)));
+    string desc = string("Debug level for ") + values.subsys.get_name(i);
+    opt.set_description(desc.c_str());
+    opt.set_flag(Option::FLAG_RUNTIME);
+    opt.set_long_description("The value takes the form 'N' or 'N/M' where N and M are values between 0 and 99.  N is the debug level to log (all values below this are included), and M is the level to gather and buffer in memory.  In the event of a crash, the most recent items <= M are dumped to the log file.");
+    opt.set_subsys(i);
+    opt.set_validator([](std::string *value, std::string *error_message) {
+	int m, n;
+	int r = sscanf(value->c_str(), "%d/%d", &m, &n);
+	if (r >= 1) {
+	  if (m < 0 || m > 99) {
+	    *error_message = "value must be in range [0, 99]";
+	    return -ERANGE;
+	  }
+	  if (r == 2) {
+	    if (n < 0 || n > 99) {
+	      *error_message = "value must be in range [0, 99]";
+	      return -ERANGE;
+	    }
+	  } else {
+	    // normalize to M/N
+	    n = m;
+	    *value = stringify(m) + "/" + stringify(n);
+	  }
+	} else {
+	  *error_message = "value must take the form N or N/M, where N and M are integers";
+	  return -EINVAL;
+	}
+	return 0;
+      });
+  }
+  for (auto& opt : subsys_options) {
+    schema.emplace(opt.name, opt);
+  }
+
+  // Populate list of legacy_values according to the OPTION() definitions
+  // Note that this is just setting up our map of name->member ptr.  The
+  // default values etc will get loaded in along with new-style data,
+  // as all loads write to both the values map, and the legacy
+  // members if present.
+  legacy_values = {
+#define OPTION(name, type) \
+    {std::string(STRINGIFY(name)), &ConfigValues::name},
+#define SAFE_OPTION(name, type) OPTION(name, type)
+#include "common/legacy_config_opts.h"
+#undef OPTION
+#undef SAFE_OPTION
+  };
+
+  validate_schema();
+
+  // Validate default values from the schema
+  for (const auto &i : schema) {
+    const Option &opt = i.second;
+    if (opt.type == Option::TYPE_STR) {
+      bool has_daemon_default = !boost::get<boost::blank>(&opt.daemon_value);
+      Option::value_t default_val;
+      if (is_daemon && has_daemon_default) {
+	default_val = opt.daemon_value;
+      } else {
+	default_val = opt.value;
+      }
+      // We call pre_validate as a sanity check, but also to get any
+      // side effect (value modification) from the validator.
+      std::string *def_str = boost::get<std::string>(&default_val);
+      std::string val = *def_str;
+      std::string err;
+      if (opt.pre_validate(&val, &err) != 0) {
+        std::cerr << "Default value " << opt.name << "=" << *def_str << " is "
+                     "invalid: " << err << std::endl;
+
+        // This is the compiled-in default that is failing its own option's
+        // validation, so this is super-invalid and should never make it
+        // past a pull request: crash out.
+        ceph_abort();
+      }
+      if (val != *def_str) {
+	// if the validator normalizes the string into a different form than
+	// what was compiled in, use that.
+	set_val_default(values, tracker, opt.name, val);
+      }
+    }
+  }
+
+  // Copy out values (defaults) into any legacy (C struct member) fields
+  update_legacy_vals(values);
+}
+
+md_config_t::~md_config_t()
+{
+}
+
+/**
+ * Sanity check schema.  Assert out on failures, to ensure any bad changes
+ * cannot possibly pass any testing and make it into a release.
+ */
+void md_config_t::validate_schema()
+{
+  for (const auto &i : schema) {
+    const auto &opt = i.second;
+    for (const auto &see_also_key : opt.see_also) {
+      if (schema.count(see_also_key) == 0) {
+        std::cerr << "Non-existent see-also key '" << see_also_key
+                  << "' on option '" << opt.name << "'" << std::endl;
+        ceph_abort();
+      }
+    }
+  }
+
+  for (const auto &i : legacy_values) {
+    if (schema.count(i.first) == 0) {
+      std::cerr << "Schema is missing legacy field '" << i.first << "'"
+                << std::endl;
+      ceph_abort();
+    }
+  }
+}
+
+const Option *md_config_t::find_option(const string& name) const
+{
+  auto p = schema.find(name);
+  if (p != schema.end()) {
+    return &p->second;
+  }
+  return nullptr;
+}
+
+void md_config_t::set_val_default(ConfigValues& values,
+				  const ConfigTracker& tracker,
+				  const string& name, const std::string& val)
+{
+  const Option *o = find_option(name);
+  ceph_assert(o);
+  string err;
+  int r = _set_val(values, tracker, val, *o, CONF_DEFAULT, &err);
+  ceph_assert(r >= 0);
+}
+
+int md_config_t::set_mon_vals(CephContext *cct,
+    ConfigValues& values,
+    const ConfigTracker& tracker,
+    const map<string,string>& kv,
+    config_callback config_cb)
+{
+  ignored_mon_values.clear();
+
+  if (!config_cb) {
+    ldout(cct, 4) << __func__ << " no callback set" << dendl;
+  }
+
+  for (auto& i : kv) {
+    if (config_cb) {
+      if (config_cb(i.first, i.second)) {
+	ldout(cct, 4) << __func__ << " callback consumed " << i.first << dendl;
+	continue;
+      }
+      ldout(cct, 4) << __func__ << " callback ignored " << i.first << dendl;
+    }
+    const Option *o = find_option(i.first);
+    if (!o) {
+      ldout(cct,10) << __func__ << " " << i.first << " = " << i.second
+		    << " (unrecognized option)" << dendl;
+      continue;
+    }
+    if (o->has_flag(Option::FLAG_NO_MON_UPDATE)) {
+      ignored_mon_values.emplace(i);
+      continue;
+    }
+    std::string err;
+    int r = _set_val(values, tracker, i.second, *o, CONF_MON, &err);
+    if (r < 0) {
+      ldout(cct, 4) << __func__ << " failed to set " << i.first << " = "
+		    << i.second << ": " << err << dendl;
+      ignored_mon_values.emplace(i);
+    } else if (r == ConfigValues::SET_NO_CHANGE ||
+	       r == ConfigValues::SET_NO_EFFECT) {
+      ldout(cct,20) << __func__ << " " << i.first << " = " << i.second
+		    << " (no change)" << dendl;
+    } else if (r == ConfigValues::SET_HAVE_EFFECT) {
+      ldout(cct,10) << __func__ << " " << i.first << " = " << i.second << dendl;
+    } else {
+      ceph_abort();
+    }
+  }
+  values.for_each([&] (auto name, auto configs) {
+    auto config = configs.find(CONF_MON);
+    if (config == configs.end()) {
+      return;
+    }
+    if (kv.find(name) != kv.end()) {
+      return;
+    }
+    ldout(cct,10) << __func__ << " " << name
+		  << " cleared (was " << Option::to_str(config->second) << ")"
+		  << dendl;
+    values.rm_val(name, CONF_MON);
+    // if this is a debug option, it needs to propagate to teh subsys;
+    // this isn't covered by update_legacy_vals() below.  similarly,
+    // we want to trigger a config notification for these items.
+    const Option *o = find_option(name);
+    _refresh(values, *o);
+  });
+  values_bl.clear();
+  update_legacy_vals(values);
+  return 0;
+}
+
+int md_config_t::parse_config_files(ConfigValues& values,
+				    const ConfigTracker& tracker,
+				    const char *conf_files_str,
+				    std::ostream *warnings,
+				    int flags)
+{
+
+  if (safe_to_start_threads)
+    return -ENOSYS;
+
+  if (!values.cluster.size() && !conf_files_str) {
+    /*
+     * set the cluster name to 'ceph' when neither cluster name nor
+     * configuration file are specified.
+     */
+    values.cluster = "ceph";
+  }
+
+  if (!conf_files_str) {
+    const char *c = getenv("CEPH_CONF");
+    if (c) {
+      conf_files_str = c;
+    }
+    else {
+      if (flags & CINIT_FLAG_NO_DEFAULT_CONFIG_FILE)
+	return 0;
+      conf_files_str = CEPH_CONF_FILE_DEFAULT;
+    }
+  }
+
+  std::list<std::string> conf_files;
+  get_str_list(conf_files_str, conf_files);
+  auto p = conf_files.begin();
+  while (p != conf_files.end()) {
+    string &s = *p;
+    if (s.find("$data_dir") != string::npos &&
+	data_dir_option.empty()) {
+      // useless $data_dir item, skip
+      p = conf_files.erase(p);
+    } else {
+      early_expand_meta(values, s, warnings);
+      ++p;
+    }
+  }
+
+  // open new conf
+  list<string>::const_iterator c;
+  for (c = conf_files.begin(); c != conf_files.end(); ++c) {
+    cf.clear();
+    string fn = *c;
+
+    int ret = cf.parse_file(fn.c_str(), &parse_errors, warnings);
+    if (ret == 0)
+      break;
+    else if (ret != -ENOENT)
+      return ret;
+  }
+  // it must have been all ENOENTs, that's the only way we got here
+  if (c == conf_files.end())
+    return -ENOENT;
+
+  if (values.cluster.size() == 0) {
+    /*
+     * If cluster name is not set yet, use the prefix of the
+     * basename of configuration file as cluster name.
+     */
+    auto start = c->rfind('/') + 1;
+    auto end = c->find(".conf", start);
+    if (end == c->npos) {
+        /*
+         * If the configuration file does not follow $cluster.conf
+         * convention, we do the last try and assign the cluster to
+         * 'ceph'.
+         */
+        values.cluster = "ceph";
+    } else {
+      values.cluster = c->substr(start, end - start);
+    }
+  }
+
+  std::vector <std::string> my_sections;
+  _get_my_sections(values, my_sections);
+  for (const auto &i : schema) {
+    const auto &opt = i.second;
+    std::string val;
+    int ret = _get_val_from_conf_file(my_sections, opt.name, val);
+    if (ret == 0) {
+      std::string error_message;
+      int r = _set_val(values, tracker, val, opt, CONF_FILE, &error_message);
+      if (warnings != nullptr && (r < 0 || !error_message.empty())) {
+        *warnings << "parse error setting '" << opt.name << "' to '" << val
+                  << "'";
+        if (!error_message.empty()) {
+          *warnings << " (" << error_message << ")";
+        }
+        *warnings << std::endl;
+      }
+    }
+  }
+
+  // Warn about section names that look like old-style section names
+  std::deque < std::string > old_style_section_names;
+  for (ConfFile::const_section_iter_t s = cf.sections_begin();
+       s != cf.sections_end(); ++s) {
+    const string &str(s->first);
+    if (((str.find("mds") == 0) || (str.find("mon") == 0) ||
+	 (str.find("osd") == 0)) && (str.size() > 3) && (str[3] != '.')) {
+      old_style_section_names.push_back(str);
+    }
+  }
+  if (!old_style_section_names.empty()) {
+    ostringstream oss;
+    cerr << "ERROR! old-style section name(s) found: ";
+    string sep;
+    for (std::deque < std::string >::const_iterator os = old_style_section_names.begin();
+	 os != old_style_section_names.end(); ++os) {
+      cerr << sep << *os;
+      sep = ", ";
+    }
+    cerr << ". Please use the new style section names that include a period.";
+  }
+
+  update_legacy_vals(values);
+
+  return 0;
+}
+
+void md_config_t::parse_env(unsigned entity_type,
+			    ConfigValues& values,
+			    const ConfigTracker& tracker,
+			    const char *args_var)
+{
+  if (safe_to_start_threads)
+    return;
+  if (!args_var) {
+    args_var = "CEPH_ARGS";
+  }
+  if (auto s = getenv("CEPH_KEYRING"); s) {
+    string err;
+    _set_val(values, tracker, s, *find_option("keyring"), CONF_ENV, &err);
+  }
+  if (auto dir = getenv("CEPH_LIB"); dir) {
+    for (auto name : { "erasure_code_dir", "plugin_dir", "osd_class_dir" }) {
+    std::string err;
+      const Option *o = find_option(name);
+      ceph_assert(o);
+      _set_val(values, tracker, dir, *o, CONF_ENV, &err);
+    }
+  }
+
+  // Apply pod memory limits:
+  //
+  // There are two types of resource requests: `limits` and `requests`.
+  //
+  // - Requests: Used by the K8s scheduler to determine on which nodes to
+  //   schedule the pods. This helps spread the pods to different nodes. This
+  //   value should be conservative in order to make sure all the pods are
+  //   schedulable. This corresponds to POD_MEMORY_REQUEST (set by the Rook
+  //   CRD) and is the target memory utilization we try to maintain for daemons
+  //   that respect it.
+  //
+  //   If POD_MEMORY_REQUEST is present, we use it as the target.
+  //
+  // - Limits: At runtime, the container runtime (and Linux) will use the
+  //   limits to see if the pod is using too many resources. In that case, the
+  //   pod will be killed/restarted automatically if the pod goes over the limit.
+  //   This should be higher than what is specified for requests (potentially
+  //   much higher). This corresponds to the cgroup memory limit that will
+  //   trigger the Linux OOM killer.
+  //
+  //   If POD_MEMORY_LIMIT is present, we use it as the /default/ value for
+  //   the target, which means it will only apply if the *_memory_target option
+  //   isn't set via some other path (e.g., POD_MEMORY_REQUEST, or the cluster
+  //   config, or whatever.)
+  //
+  // Here are the documented best practices:
+  //   https://kubernetes.io/docs/tasks/configure-pod-container/assign-cpu-resource/#motivation-for-cpu-requests-and-limits
+  //
+  // When the operator creates the CephCluster CR, it will need to generate the
+  // desired requests and limits. As long as we are conservative in our choice
+  // for requests and generous with the limits we should be in a good place to
+  // get started.
+  //
+  // The support in Rook is already there for applying the limits as seen in
+  // these links.
+  //
+  // Rook docs on the resource requests and limits:
+  //   https://rook.io/docs/rook/v1.0/ceph-cluster-crd.html#cluster-wide-resources-configuration-settings
+  // Example CR settings:
+  //   https://github.com/rook/rook/blob/6d2ef936698593036185aabcb00d1d74f9c7bfc1/cluster/examples/kubernetes/ceph/cluster.yaml#L90
+  //
+  uint64_t pod_limit = 0, pod_request = 0;
+  if (auto pod_lim = getenv("POD_MEMORY_LIMIT"); pod_lim) {
+    string err;
+    uint64_t v = atoll(pod_lim);
+    if (v) {
+      switch (entity_type) {
+      case CEPH_ENTITY_TYPE_OSD:
+        {
+	  double cgroup_ratio = get_val<double>(
+	    values, "osd_memory_target_cgroup_limit_ratio");
+	  if (cgroup_ratio > 0.0) {
+	    pod_limit = v * cgroup_ratio;
+	    // set osd_memory_target *default* based on cgroup limit, so that
+	    // it can be overridden by any explicit settings elsewhere.
+	    set_val_default(values, tracker,
+			    "osd_memory_target", stringify(pod_limit));
+	  }
+	}
+      }
+    }
+  }
+  if (auto pod_req = getenv("POD_MEMORY_REQUEST"); pod_req) {
+    if (uint64_t v = atoll(pod_req); v) {
+      pod_request = v;
+    }
+  }
+  if (pod_request && pod_limit) {
+    // If both LIMIT and REQUEST are set, ensure that we use the
+    // min of request and limit*ratio.  This is important
+    // because k8s set set LIMIT == REQUEST if only LIMIT is
+    // specified, and we want to apply the ratio in that case,
+    // even though REQUEST is present.
+    pod_request = std::min<uint64_t>(pod_request, pod_limit);
+  }
+  if (pod_request) {
+    string err;
+    switch (entity_type) {
+    case CEPH_ENTITY_TYPE_OSD:
+      _set_val(values, tracker, stringify(pod_request),
+	       *find_option("osd_memory_target"),
+	       CONF_ENV, &err);
+      break;
+    }
+  }
+
+  if (getenv(args_var)) {
+    vector<const char *> env_args;
+    env_to_vec(env_args, args_var);
+    parse_argv(values, tracker, env_args, CONF_ENV);
+  }
+}
+
+void md_config_t::show_config(const ConfigValues& values,
+			      std::ostream& out) const
+{
+  _show_config(values, &out, nullptr);
+}
+
+void md_config_t::show_config(const ConfigValues& values,
+			      Formatter *f) const
+{
+  _show_config(values, nullptr, f);
+}
+
+void md_config_t::config_options(Formatter *f) const
+{
+  f->open_array_section("options");
+  for (const auto& i: schema) {
+    f->dump_object("option", i.second);
+  }
+  f->close_section();
+}
+
+void md_config_t::_show_config(const ConfigValues& values,
+			       std::ostream *out, Formatter *f) const
+{
+  if (out) {
+    *out << "name = " << values.name << std::endl;
+    *out << "cluster = " << values.cluster << std::endl;
+  }
+  if (f) {
+    f->dump_string("name", stringify(values.name));
+    f->dump_string("cluster", values.cluster);
+  }
+  for (const auto& i: schema) {
+    const Option &opt = i.second;
+    string val;
+    conf_stringify(_get_val(values, opt), &val);
+    if (out) {
+      *out << opt.name << " = " << val << std::endl;
+    }
+    if (f) {
+      f->dump_string(opt.name.c_str(), val);
+    }
+  }
+}
+
+int md_config_t::parse_argv(ConfigValues& values,
+			    const ConfigTracker& tracker,
+			    std::vector<const char*>& args, int level)
+{
+  if (safe_to_start_threads) {
+    return -ENOSYS;
+  }
+
+  // In this function, don't change any parts of the configuration directly.
+  // Instead, use set_val to set them. This will allow us to send the proper
+  // observer notifications later.
+  std::string val;
+  for (std::vector<const char*>::iterator i = args.begin(); i != args.end(); ) {
+    if (strcmp(*i, "--") == 0) {
+      /* Normally we would use ceph_argparse_double_dash. However, in this
+       * function we *don't* want to remove the double dash, because later
+       * argument parses will still need to see it. */
+      break;
+    }
+    else if (ceph_argparse_flag(args, i, "--show_conf", (char*)NULL)) {
+      cerr << cf << std::endl;
+      _exit(0);
+    }
+    else if (ceph_argparse_flag(args, i, "--show_config", (char*)NULL)) {
+      do_show_config = true;
+    }
+    else if (ceph_argparse_witharg(args, i, &val, "--show_config_value", (char*)NULL)) {
+      do_show_config_value = val;
+    }
+    else if (ceph_argparse_flag(args, i, "--no-mon-config", (char*)NULL)) {
+      values.no_mon_config = true;
+    }
+    else if (ceph_argparse_flag(args, i, "--log-early", (char*)NULL)) {
+      values.log_early = true;
+    }
+    else if (ceph_argparse_flag(args, i, "--mon-config", (char*)NULL)) {
+      values.no_mon_config = false;
+    }
+    else if (ceph_argparse_flag(args, i, "--foreground", "-f", (char*)NULL)) {
+      set_val_or_die(values, tracker, "daemonize", "false");
+    }
+    else if (ceph_argparse_flag(args, i, "-d", (char*)NULL)) {
+      set_val_or_die(values, tracker, "fuse_debug", "true");
+      set_val_or_die(values, tracker, "daemonize", "false");
+      set_val_or_die(values, tracker, "log_file", "");
+      set_val_or_die(values, tracker, "log_to_stderr", "true");
+      set_val_or_die(values, tracker, "err_to_stderr", "true");
+      set_val_or_die(values, tracker, "log_to_syslog", "false");
+    }
+    // Some stuff that we wanted to give universal single-character options for
+    // Careful: you can burn through the alphabet pretty quickly by adding
+    // to this list.
+    else if (ceph_argparse_witharg(args, i, &val, "--monmap", "-M", (char*)NULL)) {
+      set_val_or_die(values, tracker, "monmap", val.c_str());
+    }
+    else if (ceph_argparse_witharg(args, i, &val, "--mon_host", "-m", (char*)NULL)) {
+      set_val_or_die(values, tracker, "mon_host", val.c_str());
+    }
+    else if (ceph_argparse_witharg(args, i, &val, "--bind", (char*)NULL)) {
+      set_val_or_die(values, tracker, "public_addr", val.c_str());
+    }
+    else if (ceph_argparse_witharg(args, i, &val, "--keyfile", "-K", (char*)NULL)) {
+      bufferlist bl;
+      string err;
+      int r;
+      if (val == "-") {
+	r = bl.read_fd(STDIN_FILENO, 1024);
+      } else {
+	r = bl.read_file(val.c_str(), &err);
+      }
+      if (r >= 0) {
+	string k(bl.c_str(), bl.length());
+	set_val_or_die(values, tracker, "key", k.c_str());
+      }
+    }
+    else if (ceph_argparse_witharg(args, i, &val, "--keyring", "-k", (char*)NULL)) {
+      set_val_or_die(values, tracker, "keyring", val.c_str());
+    }
+    else if (ceph_argparse_witharg(args, i, &val, "--client_mountpoint", "-r", (char*)NULL)) {
+      set_val_or_die(values, tracker, "client_mountpoint", val.c_str());
+    }
+    else {
+      int r = parse_option(values, tracker, args, i, NULL, level);
+      if (r < 0) {
+        return r;
+      }
+    }
+  }
+  // meta expands could have modified anything.  Copy it all out again.
+  update_legacy_vals(values);
+  return 0;
+}
+
+void md_config_t::do_argv_commands(const ConfigValues& values) const
+{
+
+  if (do_show_config) {
+    _show_config(values, &cout, NULL);
+    _exit(0);
+  }
+
+  if (do_show_config_value.size()) {
+    string val;
+    int r = conf_stringify(_get_val(values, do_show_config_value, 0, &cerr),
+			   &val);
+    if (r < 0) {
+      if (r == -ENOENT)
+	std::cerr << "failed to get config option '"
+		  << do_show_config_value << "': option not found" << std::endl;
+      else
+	std::cerr << "failed to get config option '"
+		  << do_show_config_value << "': " << cpp_strerror(r)
+		  << std::endl;
+      _exit(1);
+    }
+    std::cout << val << std::endl;
+    _exit(0);
+  }
+}
+
+int md_config_t::parse_option(ConfigValues& values,
+			      const ConfigTracker& tracker,
+			      std::vector<const char*>& args,
+			      std::vector<const char*>::iterator& i,
+			      ostream *oss,
+			      int level)
+{
+  int ret = 0;
+  size_t o = 0;
+  std::string val;
+
+  std::string option_name;
+  std::string error_message;
+  o = 0;
+  for (const auto& opt_iter: schema) {
+    const Option &opt = opt_iter.second;
+    ostringstream err;
+    std::string as_option("--");
+    as_option += opt.name;
+    option_name = opt.name;
+    if (ceph_argparse_witharg(
+	  args, i, &val, err,
+	  string(string("--default-") + opt.name).c_str(), (char*)NULL)) {
+      if (!err.str().empty()) {
+        error_message = err.str();
+	ret = -EINVAL;
+	break;
+      }
+      ret = _set_val(values, tracker,  val, opt, CONF_DEFAULT, &error_message);
+      break;
+    } else if (opt.type == Option::TYPE_BOOL) {
+      int res;
+      if (ceph_argparse_binary_flag(args, i, &res, oss, as_option.c_str(),
+				    (char*)NULL)) {
+	if (res == 0)
+	  ret = _set_val(values, tracker, "false", opt, level, &error_message);
+	else if (res == 1)
+	  ret = _set_val(values, tracker, "true", opt, level, &error_message);
+	else
+	  ret = res;
+	break;
+      } else {
+	std::string no("--no-");
+	no += opt.name;
+	if (ceph_argparse_flag(args, i, no.c_str(), (char*)NULL)) {
+	  ret = _set_val(values, tracker, "false", opt, level, &error_message);
+	  break;
+	}
+      }
+    } else if (ceph_argparse_witharg(args, i, &val, err,
+                                     as_option.c_str(), (char*)NULL)) {
+      if (!err.str().empty()) {
+        error_message = err.str();
+	ret = -EINVAL;
+	break;
+      }
+      ret = _set_val(values, tracker,  val, opt, level, &error_message);
+      break;
+    }
+    ++o;
+  }
+
+  if (ret < 0 || !error_message.empty()) {
+    ceph_assert(!option_name.empty());
+    if (oss) {
+      *oss << "Parse error setting " << option_name << " to '"
+           << val << "' using injectargs";
+      if (!error_message.empty()) {
+        *oss << " (" << error_message << ")";
+      }
+      *oss << ".\n";
+    } else {
+      cerr << "parse error setting '" << option_name << "' to '"
+	   << val << "'";
+      if (!error_message.empty()) {
+        cerr << " (" << error_message << ")";
+      }
+      cerr << "\n" << std::endl;
+    }
+  }
+
+  if (o == schema.size()) {
+    // ignore
+    ++i;
+  }
+  return ret >= 0 ? 0 : ret;
+}
+
+int md_config_t::parse_injectargs(ConfigValues& values,
+				  const ConfigTracker& tracker,
+				  std::vector<const char*>& args,
+				  std::ostream *oss)
+{
+  int ret = 0;
+  for (std::vector<const char*>::iterator i = args.begin(); i != args.end(); ) {
+    int r = parse_option(values, tracker, args, i, oss, CONF_OVERRIDE);
+    if (r < 0)
+      ret = r;
+  }
+  return ret;
+}
+
+void md_config_t::set_safe_to_start_threads()
+{
+  safe_to_start_threads = true;
+}
+
+void md_config_t::_clear_safe_to_start_threads()
+{
+  safe_to_start_threads = false;
+}
+
+int md_config_t::injectargs(ConfigValues& values,
+			    const ConfigTracker& tracker,
+			    const std::string& s, std::ostream *oss)
+{
+  int ret;
+  char b[s.length()+1];
+  strcpy(b, s.c_str());
+  std::vector<const char*> nargs;
+  char *p = b;
+  while (*p) {
+    nargs.push_back(p);
+    while (*p && *p != ' ') p++;
+    if (!*p)
+      break;
+    *p++ = 0;
+    while (*p && *p == ' ') p++;
+  }
+  ret = parse_injectargs(values, tracker, nargs, oss);
+  if (!nargs.empty()) {
+    *oss << " failed to parse arguments: ";
+    std::string prefix;
+    for (std::vector<const char*>::const_iterator i = nargs.begin();
+	 i != nargs.end(); ++i) {
+      *oss << prefix << *i;
+      prefix = ",";
+    }
+    *oss << "\n";
+    ret = -EINVAL;
+  }
+  update_legacy_vals(values);
+  return ret;
+}
+
+void md_config_t::set_val_or_die(ConfigValues& values,
+				 const ConfigTracker& tracker,
+				 const std::string &key,
+				 const std::string &val)
+{
+  std::stringstream err;
+  int ret = set_val(values, tracker, key, val, &err);
+  if (ret != 0) {
+    std::cerr << "set_val_or_die(" << key << "): " << err.str();
+  }
+  ceph_assert(ret == 0);
+}
+
+int md_config_t::set_val(ConfigValues& values,
+			 const ConfigTracker& tracker,
+			 const std::string &key, const char *val,
+			 std::stringstream *err_ss)
+{
+  if (key.empty()) {
+    if (err_ss) *err_ss << "No key specified";
+    return -EINVAL;
+  }
+  if (!val) {
+    return -EINVAL;
+  }
+
+  std::string v(val);
+
+  string k(ConfFile::normalize_key_name(key));
+
+  const auto &opt_iter = schema.find(k);
+  if (opt_iter != schema.end()) {
+    const Option &opt = opt_iter->second;
+    std::string error_message;
+    int r = _set_val(values, tracker, v, opt, CONF_OVERRIDE, &error_message);
+    if (r >= 0) {
+      if (err_ss) *err_ss << "Set " << opt.name << " to " << v;
+      r = 0;
+    } else {
+      if (err_ss) *err_ss << error_message;
+    }
+    return r;
+  }
+
+  if (err_ss) *err_ss << "Configuration option not found: '" << key << "'";
+  return -ENOENT;
+}
+
+int md_config_t::rm_val(ConfigValues& values, const std::string& key)
+{
+  return _rm_val(values, key, CONF_OVERRIDE);
+}
+
+void md_config_t::get_defaults_bl(const ConfigValues& values,
+					 bufferlist *bl)
+{
+  if (defaults_bl.length() == 0) {
+    uint32_t n = 0;
+    bufferlist bl;
+    for (const auto &i : schema) {
+      ++n;
+      encode(i.second.name, bl);
+      auto [value, found] = values.get_value(i.second.name, CONF_DEFAULT);
+      if (found) {
+	encode(Option::to_str(value), bl);
+      } else {
+	string val;
+	conf_stringify(_get_val_default(i.second), &val);
+	encode(val, bl);
+      }
+    }
+    encode(n, defaults_bl);
+    defaults_bl.claim_append(bl);
+  }
+  *bl = defaults_bl;
+}
+
+void md_config_t::get_config_bl(
+  const ConfigValues& values,
+  uint64_t have_version,
+  bufferlist *bl,
+  uint64_t *got_version)
+{
+  if (values_bl.length() == 0) {
+    uint32_t n = 0;
+    bufferlist bl;
+    values.for_each([&](auto& name, auto& configs) {
+      if (name == "fsid" ||
+	  name == "host") {
+	return;
+      }
+      ++n;
+      encode(name, bl);
+      encode((uint32_t)configs.size(), bl);
+      for (auto& j : configs) {
+	encode(j.first, bl);
+	encode(Option::to_str(j.second), bl);
+      }
+    });
+    // make sure overridden items appear, and include the default value
+    for (auto& i : ignored_mon_values) {
+      if (values.contains(i.first)) {
+	continue;
+      }
+      if (i.first == "fsid" ||
+	  i.first == "host") {
+	continue;
+      }
+      const Option *opt = find_option(i.first);
+      if (!opt) {
+	continue;
+      }
+      ++n;
+      encode(i.first, bl);
+      encode((uint32_t)1, bl);
+      encode((int32_t)CONF_DEFAULT, bl);
+      string val;
+      conf_stringify(_get_val_default(*opt), &val);
+      encode(val, bl);
+    }
+    encode(n, values_bl);
+    values_bl.claim_append(bl);
+    encode(ignored_mon_values, values_bl);
+    ++values_bl_version;
+  }
+  if (have_version != values_bl_version) {
+    *bl = values_bl;
+    *got_version = values_bl_version;
+  }
+}
+
+int md_config_t::get_val(const ConfigValues& values,
+			 const std::string &key, char **buf, int len) const
+{
+  string k(ConfFile::normalize_key_name(key));
+  return _get_val_cstr(values, k, buf, len);
+}
+
+int md_config_t::get_val(
+  const ConfigValues& values,
+  const std::string &key,
+  std::string *val) const
+{
+  return conf_stringify(get_val_generic(values, key), val);
+}
+
+Option::value_t md_config_t::get_val_generic(
+  const ConfigValues& values,
+  const std::string &key) const
+{
+  string k(ConfFile::normalize_key_name(key));
+  return _get_val(values, k);
+}
+
+Option::value_t md_config_t::_get_val(
+  const ConfigValues& values,
+  const std::string &key,
+  expand_stack_t *stack,
+  std::ostream *err) const
+{
+  if (key.empty()) {
+    return Option::value_t(boost::blank());
+  }
+
+  // In key names, leading and trailing whitespace are not significant.
+  string k(ConfFile::normalize_key_name(key));
+
+  const Option *o = find_option(key);
+  if (!o) {
+    // not a valid config option
+    return Option::value_t(boost::blank());
+  }
+
+  return _get_val(values, *o, stack, err);
+}
+
+Option::value_t md_config_t::_get_val(
+  const ConfigValues& values,
+  const Option& o,
+  expand_stack_t *stack,
+  std::ostream *err) const
+{
+  expand_stack_t a_stack;
+  if (!stack) {
+    stack = &a_stack;
+  }
+  return _expand_meta(values,
+		      _get_val_nometa(values, o),
+		      &o, stack, err);
+}
+
+Option::value_t md_config_t::_get_val_nometa(const ConfigValues& values,
+					     const Option& o) const
+{
+  if (auto [value, found] = values.get_value(o.name, -1); found) {
+    return value;
+  } else {
+    return _get_val_default(o);
+  }
+}
+
+const Option::value_t& md_config_t::_get_val_default(const Option& o) const
+{
+  bool has_daemon_default = !boost::get<boost::blank>(&o.daemon_value);
+  if (is_daemon && has_daemon_default) {
+    return o.daemon_value;
+  } else {
+    return o.value;
+  }
+}
+
+void md_config_t::early_expand_meta(
+  const ConfigValues& values,
+  std::string &val,
+  std::ostream *err) const
+{
+  expand_stack_t stack;
+  Option::value_t v = _expand_meta(values,
+				   Option::value_t(val),
+				   nullptr, &stack, err);
+  conf_stringify(v, &val);
+}
+
+bool md_config_t::finalize_reexpand_meta(ConfigValues& values,
+					 const ConfigTracker& tracker)
+{
+  std::vector<std::string> reexpands;
+  reexpands.swap(may_reexpand_meta);
+  for (auto& name : reexpands) {
+    // always refresh the options if they are in the may_reexpand_meta
+    // map, because the options may have already been expanded with old
+    // meta.
+    const auto &opt_iter = schema.find(name);
+    ceph_assert(opt_iter != schema.end());
+    const Option &opt = opt_iter->second;
+    _refresh(values, opt);
+  }
+
+  return !may_reexpand_meta.empty();
+}
+
+Option::value_t md_config_t::_expand_meta(
+  const ConfigValues& values,
+  const Option::value_t& in,
+  const Option *o,
+  expand_stack_t *stack,
+  std::ostream *err) const
+{
+  //cout << __func__ << " in '" << in << "' stack " << stack << std::endl;
+  if (!stack) {
+    return in;
+  }
+  const std::string *str = boost::get<const std::string>(&in);
+  if (!str) {
+    // strings only!
+    return in;
+  }
+
+  auto pos = str->find('$');
+  if (pos == std::string::npos) {
+    // no substitutions!
+    return in;
+  }
+
+  if (o) {
+    stack->push_back(make_pair(o, &in));
+  }
+  string out;
+  decltype(pos) last_pos = 0;
+  while (pos != std::string::npos) {
+    ceph_assert((*str)[pos] == '$');
+    if (pos > last_pos) {
+      out += str->substr(last_pos, pos - last_pos);
+    }
+
+    // try to parse the variable name into var, either \$\{(.+)\} or
+    // \$[a-z\_]+
+    const char *valid_chars = "abcdefghijklmnopqrstuvwxyz_";
+    string var;
+    size_t endpos = 0;
+    if ((*str)[pos+1] == '{') {
+      // ...${foo_bar}...
+      endpos = str->find_first_not_of(valid_chars, pos + 2);
+      if (endpos != std::string::npos &&
+	  (*str)[endpos] == '}') {
+	var = str->substr(pos + 2, endpos - pos - 2);
+	endpos++;
+      }
+    } else {
+      // ...$foo...
+      endpos = str->find_first_not_of(valid_chars, pos + 1);
+      if (endpos != std::string::npos)
+	var = str->substr(pos + 1, endpos - pos - 1);
+      else
+	var = str->substr(pos + 1);
+    }
+    last_pos = endpos;
+
+    if (!var.size()) {
+      out += '$';
+    } else {
+      //cout << " found var " << var << std::endl;
+      // special metavariable?
+      if (var == "type") {
+	out += values.name.get_type_name();
+      } else if (var == "cluster") {
+	out += values.cluster;
+      } else if (var == "name") {
+	out += values.name.to_cstr();
+      } else if (var == "host") {
+	if (values.host == "") {
+	  out += ceph_get_short_hostname();
+	} else {
+	  out += values.host;
+	}
+      } else if (var == "num") {
+	out += values.name.get_id().c_str();
+      } else if (var == "id") {
+	out += values.name.get_id();
+      } else if (var == "pid") {
+	out += stringify(getpid());
+        if (o) {
+          may_reexpand_meta.push_back(o->name);
+        }
+      } else if (var == "cctid") {
+	out += stringify((unsigned long long)this);
+      } else if (var == "home") {
+	const char *home = getenv("HOME");
+	out = home ? std::string(home) : std::string();
+      } else {
+	if (var == "data_dir") {
+	  var = data_dir_option;
+	}
+	const Option *o = find_option(var);
+	if (!o) {
+	  out += str->substr(pos, endpos - pos);
+	} else {
+	  auto match = std::find_if(
+	    stack->begin(), stack->end(),
+	    [o](pair<const Option *,const Option::value_t*>& item) {
+	      return item.first == o;
+	    });
+	  if (match != stack->end()) {
+	    // substitution loop; break the cycle
+	    if (err) {
+	      *err << "variable expansion loop at " << var << "="
+		   << Option::to_str(*match->second) << "\n"
+		   << "expansion stack:\n";
+	      for (auto i = stack->rbegin(); i != stack->rend(); ++i) {
+		*err << i->first->name << "="
+		     << Option::to_str(*i->second) << "\n";
+	      }
+	    }
+	    return Option::value_t(std::string("$") + o->name);
+	  } else {
+	    // recursively evaluate!
+	    string n;
+	    conf_stringify(_get_val(values, *o, stack, err), &n);
+	    out += n;
+	  }
+	}
+      }
+    }
+    pos = str->find('$', last_pos);
+  }
+  if (last_pos != std::string::npos) {
+    out += str->substr(last_pos);
+  }
+  if (o) {
+    stack->pop_back();
+  }
+
+  return Option::value_t(out);
+}
+
+int md_config_t::_get_val_cstr(
+  const ConfigValues& values,
+  const std::string &key, char **buf, int len) const
+{
+  if (key.empty())
+    return -EINVAL;
+
+  string val;
+  if (conf_stringify(_get_val(values, key), &val) == 0) {
+    int l = val.length() + 1;
+    if (len == -1) {
+      *buf = (char*)malloc(l);
+      if (!*buf)
+        return -ENOMEM;
+      strncpy(*buf, val.c_str(), l);
+      return 0;
+    }
+    snprintf(*buf, len, "%s", val.c_str());
+    return (l > len) ? -ENAMETOOLONG : 0;
+  }
+
+  string k(ConfFile::normalize_key_name(key));
+
+  // couldn't find a configuration option with key 'k'
+  return -ENOENT;
+}
+
+void md_config_t::get_all_keys(std::vector<std::string> *keys) const {
+  const std::string negative_flag_prefix("no_");
+
+  keys->clear();
+  keys->reserve(schema.size());
+  for (const auto &i: schema) {
+    const Option &opt = i.second;
+    keys->push_back(opt.name);
+    if (opt.type == Option::TYPE_BOOL) {
+      keys->push_back(negative_flag_prefix + opt.name);
+    }
+  }
+}
+
+/* The order of the sections here is important.  The first section in the
+ * vector is the "highest priority" section; if we find it there, we'll stop
+ * looking. The lowest priority section is the one we look in only if all
+ * others had nothing.  This should always be the global section.
+ */
+void md_config_t::get_my_sections(const ConfigValues& values,
+				  std::vector <std::string> &sections) const
+{
+  _get_my_sections(values, sections);
+}
+
+void md_config_t::_get_my_sections(const ConfigValues& values,
+				   std::vector <std::string> &sections) const
+{
+  sections.push_back(values.name.to_str());
+
+  sections.push_back(values.name.get_type_name());
+
+  sections.push_back("global");
+}
+
+// Return a list of all sections
+int md_config_t::get_all_sections(std::vector <std::string> &sections) const
+{
+  for (ConfFile::const_section_iter_t s = cf.sections_begin();
+       s != cf.sections_end(); ++s) {
+    sections.push_back(s->first);
+  }
+  return 0;
+}
+
+int md_config_t::get_val_from_conf_file(
+  const ConfigValues& values,
+  const std::vector <std::string> &sections,
+  const std::string &key,
+  std::string &out,
+  bool emeta) const
+{
+  int r = _get_val_from_conf_file(sections, key, out);
+  if (r < 0) {
+    return r;
+  }
+  if (emeta) {
+    expand_stack_t stack;
+    auto v = _expand_meta(values, Option::value_t(out), nullptr, &stack, nullptr);
+    conf_stringify(v, &out);
+  }
+  return 0;
+}
+
+int md_config_t::_get_val_from_conf_file(
+  const std::vector <std::string> &sections,
+  const std::string &key,
+  std::string &out) const
+{
+  std::vector <std::string>::const_iterator s = sections.begin();
+  std::vector <std::string>::const_iterator s_end = sections.end();
+  for (; s != s_end; ++s) {
+    int ret = cf.read(s->c_str(), key, out);
+    if (ret == 0) {
+      return 0;
+    } else if (ret != -ENOENT) {
+      return ret;
+    }
+  }
+  return -ENOENT;
+}
+
+int md_config_t::_set_val(
+  ConfigValues& values,
+  const ConfigTracker& observers,
+  const std::string &raw_val,
+  const Option &opt,
+  int level,
+  std::string *error_message)
+{
+  Option::value_t new_value;
+  ceph_assert(error_message);
+  int r = opt.parse_value(raw_val, &new_value, error_message);
+  if (r < 0) {
+    return r;
+  }
+
+  // unsafe runtime change?
+  if (!opt.can_update_at_runtime() &&
+      safe_to_start_threads &&
+      !observers.is_tracking(opt.name)) {
+    // accept value if it is not actually a change
+    if (new_value != _get_val_nometa(values, opt)) {
+      *error_message = string("Configuration option '") + opt.name +
+	"' may not be modified at runtime";
+      return -ENOSYS;
+    }
+  }
+
+  // Apply the value to its entry in the `values` map
+  auto result = values.set_value(opt.name, std::move(new_value), level);
+  switch (result) {
+  case ConfigValues::SET_NO_CHANGE:
+    break;
+  case ConfigValues::SET_NO_EFFECT:
+    values_bl.clear();
+    break;
+  case ConfigValues::SET_HAVE_EFFECT:
+    values_bl.clear();
+    _refresh(values, opt);
+    break;
+  }
+  return result;
+}
+
+void md_config_t::_refresh(ConfigValues& values, const Option& opt)
+{
+  // Apply the value to its legacy field, if it has one
+  auto legacy_ptr_iter = legacy_values.find(std::string(opt.name));
+  if (legacy_ptr_iter != legacy_values.end()) {
+    update_legacy_val(values, opt, legacy_ptr_iter->second);
+  }
+  // Was this a debug_* option update?
+  if (opt.subsys >= 0) {
+    string actual_val;
+    conf_stringify(_get_val(values, opt), &actual_val);
+    values.set_logging(opt.subsys, actual_val.c_str());
+  } else {
+    // normal option, advertise the change.
+    values.changed.insert(opt.name);
+  }
+}
+
+int md_config_t::_rm_val(ConfigValues& values,
+			 const std::string& key,
+			 int level)
+{
+  if (schema.count(key) == 0) {
+    return -EINVAL;
+  }
+  auto ret = values.rm_val(key, level);
+  if (ret < 0) {
+    return ret;
+  }
+  if (ret == ConfigValues::SET_HAVE_EFFECT) {
+    _refresh(values, *find_option(key));
+  }
+  values_bl.clear();
+  return 0;
+}
+
+namespace {
+template<typename Size>
+struct get_size_visitor : public boost::static_visitor<Size>
+{
+  get_size_visitor() {}
+
+  template<typename T>
+  Size operator()(const T&) const {
+    return -1;
+  }
+  Size operator()(const Option::size_t& sz) const {
+    return static_cast<Size>(sz.value);
+  }
+  Size operator()(const Size& v) const {
+    return v;
+  }
+};
+
+/**
+ * Handles assigning from a variant-of-types to a variant-of-pointers-to-types
+ */
+template<class Config>
+class assign_visitor : public boost::static_visitor<>
+{
+  Config *conf;
+  Option::value_t val;
+  public:
+
+  assign_visitor(Config *conf_, Option::value_t val_)
+    : conf(conf_), val(val_)
+  {}
+
+  template <typename T>
+  void operator()(T Config::* ptr) const
+  {
+    T *member = const_cast<T *>(&(conf->*(boost::get<const T Config::*>(ptr))));
+
+    *member = boost::get<T>(val);
+  }
+  void operator()(uint64_t Config::* ptr) const
+  {
+    using T = uint64_t;
+    auto member = const_cast<T*>(&(conf->*(boost::get<const T Config::*>(ptr))));
+    *member = boost::apply_visitor(get_size_visitor<T>{}, val);
+  }
+  void operator()(int64_t Config::* ptr) const
+  {
+    using T = int64_t;
+    auto member = const_cast<T*>(&(conf->*(boost::get<const T Config::*>(ptr))));
+    *member = boost::apply_visitor(get_size_visitor<T>{}, val);
+  }
+};
+} // anonymous namespace
+
+void md_config_t::update_legacy_vals(ConfigValues& values)
+{
+  for (const auto &i : legacy_values) {
+    const auto &name = i.first;
+    const auto &option = schema.at(name);
+    auto ptr = i.second;
+    update_legacy_val(values, option, ptr);
+  }
+}
+
+void md_config_t::update_legacy_val(ConfigValues& values,
+				    const Option &opt,
+                                    md_config_t::member_ptr_t member_ptr)
+{
+  Option::value_t v = _get_val(values, opt);
+  boost::apply_visitor(assign_visitor(&values, v), member_ptr);
+}
+
+static void dump(Formatter *f, int level, Option::value_t in)
+{
+  if (const bool *v = boost::get<const bool>(&in)) {
+    f->dump_bool(ceph_conf_level_name(level), *v);
+  } else if (const int64_t *v = boost::get<const int64_t>(&in)) {
+    f->dump_int(ceph_conf_level_name(level), *v);
+  } else if (const uint64_t *v = boost::get<const uint64_t>(&in)) {
+    f->dump_unsigned(ceph_conf_level_name(level), *v);
+  } else if (const double *v = boost::get<const double>(&in)) {
+    f->dump_float(ceph_conf_level_name(level), *v);
+  } else {
+    f->dump_stream(ceph_conf_level_name(level)) << Option::to_str(in);
+  }
+}
+
+void md_config_t::diff(
+  const ConfigValues& values,
+  Formatter *f,
+  string name) const
+{
+  values.for_each([this, f, &values] (auto& name, auto& configs) {
+    if (configs.empty()) {
+      return;
+    }
+    f->open_object_section(name.c_str());
+    const Option *o = find_option(name);
+    if (configs.size() &&
+	configs.begin()->first != CONF_DEFAULT) {
+      // show compiled-in default only if an override default wasn't provided
+      dump(f, CONF_DEFAULT, _get_val_default(*o));
+    }
+    for (auto& j : configs) {
+      dump(f, j.first, j.second);
+    }
+    dump(f, CONF_FINAL, _get_val(values, *o));
+    f->close_section();
+  });
+}
+
+void md_config_t::complain_about_parse_errors(CephContext *cct)
+{
+  ::complain_about_parse_errors(cct, &parse_errors);
+}