ceph/src/librbd/io/CopyupRequest.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_IO_COPYUP_REQUEST_H
   5 #define CEPH_LIBRBD_IO_COPYUP_REQUEST_H
   6
   7 #include "include/int_types.h"
   8 #include "include/rados/librados.hpp"
   9 #include "include/buffer.h"
  10 #include "common/Mutex.h"
  11 #include "common/zipkin_trace.h"
  12 #include "librbd/io/AsyncOperation.h"
  13 #include "librbd/io/Types.h"
  14
  15 #include <string>
  16 #include <vector>
  17
  18 namespace ZTracer { struct Trace; }
  19
  20 namespace librbd {
  21
  22 struct ImageCtx;
  23
  24 namespace io {
  25
  26 template <typename I> class AbstractObjectWriteRequest;
  27
  28 template <typename ImageCtxT = librbd::ImageCtx>
  29 class CopyupRequest {
  30 public:
  31   static CopyupRequest* create(ImageCtxT *ictx, const std::string &oid,
  32                                uint64_t objectno, Extents &&image_extents,
  33                                const ZTracer::Trace &parent_trace) {
  34     return new CopyupRequest(ictx, oid, objectno, std::move(image_extents),
  35                              parent_trace);
  36   }
  37
  38   CopyupRequest(ImageCtxT *ictx, const std::string &oid, uint64_t objectno,
  39                 Extents &&image_extents, const ZTracer::Trace &parent_trace);
  40   ~CopyupRequest();
  41
  42   void append_request(AbstractObjectWriteRequest<ImageCtxT> *req);
  43
  44   void send();
  45
  46 private:
  47   /**
  48    * Copyup requests go through the following state machine to read from the
  49    * parent image, update the object map, and copyup the object:
  50    *
  51    *
  52    * @verbatim
  53    *
  54    *              <start>
  55    *                 |
  56    *      /---------/ \---------\
  57    *      |                     |
  58    *      v                     v
  59    *  READ_FROM_PARENT      DEEP_COPY
  60    *      |                     |
  61    *      \---------\ /---------/
  62    *                 |
  63    *                 v (skip if not needed)
  64    *         UPDATE_OBJECT_MAPS
  65    *                 |
  66    *                 v (skip if not needed)
  67    *              COPYUP
  68    *                 |
  69    *                 v
  70    *              <finish>
  71    *
  72    * @endverbatim
  73    *
  74    * The OBJECT_MAP state is skipped if the object map isn't enabled or if
  75    * an object map update isn't required. The COPYUP state is skipped if
  76    * no data was read from the parent *and* there are no additional ops.
  77    */
  78
  79   typedef std::vector<AbstractObjectWriteRequest<ImageCtxT> *> WriteRequests;
  80
  81   ImageCtxT *m_image_ctx;
  82   std::string m_oid;
  83   uint64_t m_object_no;
  84   Extents m_image_extents;
  85   ZTracer::Trace m_trace;
  86
  87   bool m_flatten = false;
  88   bool m_copyup_required = true;
  89   bool m_copyup_is_zero = true;
  90
  91   ceph::bufferlist m_copyup_data;
  92
  93   AsyncOperation m_async_op;
  94
  95   std::vector<uint64_t> m_snap_ids;
  96   bool m_first_snap_is_clean = false;
  97
  98   Mutex m_lock;
  99   WriteRequests m_pending_requests;
 100   unsigned m_pending_copyups = 0;
 101
 102   WriteRequests m_restart_requests;
 103   bool m_append_request_permitted = true;
 104
 105   void read_from_parent();
 106   void handle_read_from_parent(int r);
 107
 108   void deep_copy();
 109   void handle_deep_copy(int r);
 110
 111   void update_object_maps();
 112   void handle_update_object_maps(int r);
 113
 114   void copyup();
 115   void handle_copyup(int r);
 116
 117   void finish(int r);
 118   void complete_requests(bool override_restart_retval, int r);
 119
 120   void disable_append_requests();
 121   void remove_from_list();
 122
 123   bool is_copyup_required();
 124   bool is_update_object_map_required(int r);
 125   bool is_deep_copy() const;
 126
 127   void compute_deep_copy_snap_ids();
 128 };
 129
 130 } // namespace io
 131 } // namespace librbd
 132
 133 extern template class librbd::io::CopyupRequest<librbd::ImageCtx>;
 134
 135 #endif // CEPH_LIBRBD_IO_COPYUP_REQUEST_H