ceph/src/librbd/ConfigWatcher.cc

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #include "librbd/ConfigWatcher.h"
   5 #include "common/config_obs.h"
   6 #include "common/dout.h"
   7 #include "common/errno.h"
   8 #include "librbd/ImageCtx.h"
   9 #include "librbd/ImageState.h"
  10 #include "librbd/api/Config.h"
  11 #include <deque>
  12 #include <string>
  13 #include <vector>
  14 #include <boost/algorithm/string/predicate.hpp>
  15
  16 #define dout_subsys ceph_subsys_rbd
  17 #undef dout_prefix
  18 #define dout_prefix *_dout << "librbd::ConfigWatcher: " \
  19                            << __func__ << ": "
  20
  21 namespace librbd {
  22
  23 template <typename I>
  24 struct ConfigWatcher<I>::Observer : public md_config_obs_t {
  25   ConfigWatcher<I>* m_config_watcher;
  26
  27   std::deque<std::string> m_config_key_strs;
  28   mutable std::vector<const char*> m_config_keys;
  29
  30   Observer(CephContext* cct, ConfigWatcher<I>* config_watcher)
  31     : m_config_watcher(config_watcher) {
  32     const std::string rbd_key_prefix("rbd_");
  33     auto& schema = cct->_conf.get_schema();
  34     for (auto& pair : schema) {
  35       // watch all "rbd_" keys for simplicity
  36       if (!boost::starts_with(pair.first, rbd_key_prefix)) {
  37         continue;
  38       }
  39
  40       m_config_key_strs.emplace_back(pair.first);
  41     }
  42
  43     m_config_keys.reserve(m_config_key_strs.size());
  44     for (auto& key : m_config_key_strs) {
  45       m_config_keys.emplace_back(key.c_str());
  46     }
  47     m_config_keys.emplace_back(nullptr);
  48   }
  49
  50   const char** get_tracked_conf_keys() const override {
  51     ceph_assert(!m_config_keys.empty());
  52     return &m_config_keys[0];
  53   }
  54
  55   void handle_conf_change(const ConfigProxy& conf,
  56                           const std::set <std::string> &changed) override {
  57     m_config_watcher->handle_global_config_change(changed);
  58   }
  59 };
  60
  61 template <typename I>
  62 ConfigWatcher<I>::ConfigWatcher(I& image_ctx)
  63   : m_image_ctx(image_ctx) {
  64 }
  65
  66 template <typename I>
  67 ConfigWatcher<I>::~ConfigWatcher() {
  68   ceph_assert(m_observer == nullptr);
  69 }
  70
  71 template <typename I>
  72 void ConfigWatcher<I>::init() {
  73   auto cct = m_image_ctx.cct;
  74   ldout(cct, 10) << dendl;
  75
  76   m_observer = new Observer(cct, this);
  77   cct->_conf.add_observer(m_observer);
  78 }
  79
  80 template <typename I>
  81 void ConfigWatcher<I>::shut_down() {
  82   auto cct = m_image_ctx.cct;
  83   ldout(cct, 10) << dendl;
  84
  85   ceph_assert(m_observer != nullptr);
  86   cct->_conf.remove_observer(m_observer);
  87
  88   delete m_observer;
  89   m_observer = nullptr;
  90 }
  91
  92 template <typename I>
  93 void ConfigWatcher<I>::handle_global_config_change(
  94     std::set<std::string> changed_keys) {
  95
  96   {
  97     // ignore any global changes that are being overridden
  98     std::shared_lock image_locker{m_image_ctx.image_lock};
  99     for (auto& key : m_image_ctx.config_overrides) {
 100       changed_keys.erase(key);
 101     }
 102   }
 103   if (changed_keys.empty()) {
 104     return;
 105   }
 106
 107   auto cct = m_image_ctx.cct;
 108   ldout(cct, 10) << "changed_keys=" << changed_keys << dendl;
 109
 110   // refresh the image to pick up any global config overrides
 111   m_image_ctx.state->handle_update_notification();
 112 }
 113
 114 } // namespace librbd
 115
 116 template class librbd::ConfigWatcher<librbd::ImageCtx>;