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