ceph/src/tools/rbd_mirror/image_replayer/journal/EventPreprocessor.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 "EventPreprocessor.h"
   5 #include "common/debug.h"
   6 #include "common/dout.h"
   7 #include "common/errno.h"
   8 #include "journal/Journaler.h"
   9 #include "librbd/ImageCtx.h"
  10 #include "librbd/ImageState.h"
  11 #include "librbd/Utils.h"
  12 #include "librbd/asio/ContextWQ.h"
  13 #include "librbd/journal/Types.h"
  14 #include <boost/variant.hpp>
  15
  16 #define dout_context g_ceph_context
  17 #define dout_subsys ceph_subsys_rbd_mirror
  18
  19 #undef dout_prefix
  20 #define dout_prefix *_dout << "rbd::mirror::image_replayer::journal::" \
  21                            << "EventPreprocessor: " << this << " " << __func__ \
  22                            << ": "
  23
  24 namespace rbd {
  25 namespace mirror {
  26 namespace image_replayer {
  27 namespace journal {
  28
  29 using librbd::util::create_context_callback;
  30
  31 template <typename I>
  32 EventPreprocessor<I>::EventPreprocessor(I &local_image_ctx,
  33                                         Journaler &remote_journaler,
  34                                         const std::string &local_mirror_uuid,
  35                                         MirrorPeerClientMeta *client_meta,
  36                                         librbd::asio::ContextWQ *work_queue)
  37   : m_local_image_ctx(local_image_ctx), m_remote_journaler(remote_journaler),
  38     m_local_mirror_uuid(local_mirror_uuid), m_client_meta(client_meta),
  39     m_work_queue(work_queue) {
  40 }
  41
  42 template <typename I>
  43 EventPreprocessor<I>::~EventPreprocessor() {
  44   ceph_assert(!m_in_progress);
  45 }
  46
  47 template <typename I>
  48 bool EventPreprocessor<I>::is_required(const EventEntry &event_entry) {
  49   SnapSeqs snap_seqs(m_client_meta->snap_seqs);
  50   return (prune_snap_map(&snap_seqs) ||
  51           event_entry.get_event_type() ==
  52             librbd::journal::EVENT_TYPE_SNAP_RENAME);
  53 }
  54
  55 template <typename I>
  56 void EventPreprocessor<I>::preprocess(EventEntry *event_entry,
  57                                       Context *on_finish) {
  58   ceph_assert(!m_in_progress);
  59   m_in_progress = true;
  60   m_event_entry = event_entry;
  61   m_on_finish = on_finish;
  62
  63   refresh_image();
  64 }
  65
  66 template <typename I>
  67 void EventPreprocessor<I>::refresh_image() {
  68   dout(20) << dendl;
  69
  70   Context *ctx = create_context_callback<
  71     EventPreprocessor<I>, &EventPreprocessor<I>::handle_refresh_image>(this);
  72   m_local_image_ctx.state->refresh(ctx);
  73 }
  74
  75 template <typename I>
  76 void EventPreprocessor<I>::handle_refresh_image(int r) {
  77   dout(20) << "r=" << r << dendl;
  78
  79   if (r < 0) {
  80     derr << "error encountered during image refresh: " << cpp_strerror(r)
  81          << dendl;
  82     finish(r);
  83     return;
  84   }
  85
  86   preprocess_event();
  87 }
  88
  89 template <typename I>
  90 void EventPreprocessor<I>::preprocess_event() {
  91   dout(20) << dendl;
  92
  93   m_snap_seqs = m_client_meta->snap_seqs;
  94   m_snap_seqs_updated = prune_snap_map(&m_snap_seqs);
  95
  96   int r = boost::apply_visitor(PreprocessEventVisitor(this),
  97                                m_event_entry->event);
  98   if (r < 0) {
  99     finish(r);
 100     return;
 101   }
 102
 103   update_client();
 104 }
 105
 106 template <typename I>
 107 int EventPreprocessor<I>::preprocess_snap_rename(
 108     librbd::journal::SnapRenameEvent &event) {
 109   dout(20) << "remote_snap_id=" << event.snap_id << ", "
 110            << "src_snap_name=" << event.src_snap_name << ", "
 111            << "dest_snap_name=" << event.dst_snap_name << dendl;
 112
 113   auto snap_seq_it = m_snap_seqs.find(event.snap_id);
 114   if (snap_seq_it != m_snap_seqs.end()) {
 115     dout(20) << "remapping remote snap id " << snap_seq_it->first << " "
 116              << "to local snap id " << snap_seq_it->second << dendl;
 117     event.snap_id = snap_seq_it->second;
 118     return 0;
 119   }
 120
 121   auto snap_id_it = m_local_image_ctx.snap_ids.find({cls::rbd::UserSnapshotNamespace(),
 122                                                      event.src_snap_name});
 123   if (snap_id_it == m_local_image_ctx.snap_ids.end()) {
 124     dout(20) << "cannot map remote snapshot '" << event.src_snap_name << "' "
 125              << "to local snapshot" << dendl;
 126     event.snap_id = CEPH_NOSNAP;
 127     return -ENOENT;
 128   }
 129
 130   dout(20) << "mapping remote snap id " << event.snap_id << " "
 131            << "to local snap id " << snap_id_it->second << dendl;
 132   m_snap_seqs_updated = true;
 133   m_snap_seqs[event.snap_id] = snap_id_it->second;
 134   event.snap_id = snap_id_it->second;
 135   return 0;
 136 }
 137
 138 template <typename I>
 139 void EventPreprocessor<I>::update_client() {
 140   if (!m_snap_seqs_updated) {
 141     finish(0);
 142     return;
 143   }
 144
 145   dout(20) << dendl;
 146   librbd::journal::MirrorPeerClientMeta client_meta(*m_client_meta);
 147   client_meta.snap_seqs = m_snap_seqs;
 148
 149   librbd::journal::ClientData client_data(client_meta);
 150   bufferlist data_bl;
 151   encode(client_data, data_bl);
 152
 153   Context *ctx = create_context_callback<
 154     EventPreprocessor<I>, &EventPreprocessor<I>::handle_update_client>(
 155       this);
 156   m_remote_journaler.update_client(data_bl, ctx);
 157 }
 158
 159 template <typename I>
 160 void EventPreprocessor<I>::handle_update_client(int r) {
 161   dout(20) << "r=" << r << dendl;
 162
 163   if (r < 0) {
 164     derr << "failed to update mirror peer journal client: "
 165          << cpp_strerror(r) << dendl;
 166     finish(r);
 167     return;
 168   }
 169
 170   m_client_meta->snap_seqs = m_snap_seqs;
 171   finish(0);
 172 }
 173
 174 template <typename I>
 175 bool EventPreprocessor<I>::prune_snap_map(SnapSeqs *snap_seqs) {
 176   bool pruned = false;
 177
 178   std::shared_lock image_locker{m_local_image_ctx.image_lock};
 179   for (auto it = snap_seqs->begin(); it != snap_seqs->end(); ) {
 180     auto current_it(it++);
 181     if (m_local_image_ctx.snap_info.count(current_it->second) == 0) {
 182       snap_seqs->erase(current_it);
 183       pruned = true;
 184     }
 185   }
 186   return pruned;
 187 }
 188
 189 template <typename I>
 190 void EventPreprocessor<I>::finish(int r) {
 191   dout(20) << "r=" << r << dendl;
 192
 193   Context *on_finish = m_on_finish;
 194   m_on_finish = nullptr;
 195   m_event_entry = nullptr;
 196   m_in_progress = false;
 197   m_snap_seqs_updated = false;
 198   m_work_queue->queue(on_finish, r);
 199 }
 200
 201 } // namespace journal
 202 } // namespace image_replayer
 203 } // namespace mirror
 204 } // namespace rbd
 205
 206 template class rbd::mirror::image_replayer::journal::EventPreprocessor<librbd::ImageCtx>;