ceph/src/librbd/object_map/SnapshotCreateRequest.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3
   4 #ifndef CEPH_LIBRBD_OBJECT_MAP_SNAPSHOT_CREATE_REQUEST_H
   5 #define CEPH_LIBRBD_OBJECT_MAP_SNAPSHOT_CREATE_REQUEST_H
   6
   7 #include "include/int_types.h"
   8 #include "common/bit_vector.hpp"
   9 #include "librbd/object_map/Request.h"
  10
  11 class Context;
  12
  13 namespace librbd {
  14
  15 class ImageCtx;
  16
  17 namespace object_map {
  18
  19 class SnapshotCreateRequest : public Request {
  20 public:
  21   /**
  22    * Snapshot create goes through the following state machine:
  23    *
  24    * @verbatim
  25    *
  26    * <start>
  27    *    |
  28    *    v
  29    * STATE_READ_MAP
  30    *    |
  31    *    v            (skip)
  32    * STATE_WRITE_MAP . . . . . . .
  33    *    |                        .
  34    *    v                        v
  35    * STATE_ADD_SNAPSHOT ---> <finish>
  36    *
  37    * @endverbatim
  38    *
  39    * The _ADD_SNAPSHOT state is skipped if the FAST_DIFF feature isn't enabled.
  40    */
  41   enum State {
  42     STATE_READ_MAP,
  43     STATE_WRITE_MAP,
  44     STATE_ADD_SNAPSHOT
  45   };
  46
  47   SnapshotCreateRequest(ImageCtx &image_ctx, ceph::BitVector<2> *object_map,
  48                         uint64_t snap_id, Context *on_finish)
  49     : Request(image_ctx, snap_id, on_finish),
  50       m_object_map(*object_map), m_ret_val(0) {
  51   }
  52
  53   void send() override;
  54
  55 protected:
  56   bool should_complete(int r) override;
  57
  58 private:
  59   State m_state;
  60   ceph::BitVector<2> &m_object_map;
  61
  62   bufferlist m_read_bl;
  63   int m_ret_val;
  64
  65   void send_read_map();
  66   void send_write_map();
  67   bool send_add_snapshot();
  68
  69   void update_object_map();
  70
  71 };
  72
  73 } // namespace object_map
  74 } // namespace librbd
  75
  76 #endif // CEPH_LIBRBD_OBJECT_MAP_SNAPSHOT_CREATE_REQUEST_H