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/buffer.h"
   9 #include "include/interval_set.h"
  10 #include "common/ceph_mutex.h"
  11 #include "common/zipkin_trace.h"
  12 #include "librbd/io/AsyncOperation.h"
  13 #include "librbd/io/Types.h"
  14
  15 #include <map>
  16 #include <string>
  17 #include <vector>
  18
  19 namespace ZTracer { struct Trace; }
  20
  21 namespace librbd {
  22
  23 struct ImageCtx;
  24
  25 namespace io {
  26
  27 template <typename I> class AbstractObjectWriteRequest;
  28
  29 template <typename ImageCtxT = librbd::ImageCtx>
  30 class CopyupRequest {
  31 public:
  32   static CopyupRequest* create(ImageCtxT *ictx, uint64_t objectno,
  33                                Extents &&image_extents,
  34                                const ZTracer::Trace &parent_trace) {
  35     return new CopyupRequest(ictx, objectno, std::move(image_extents),
  36                              parent_trace);
  37   }
  38
  39   CopyupRequest(ImageCtxT *ictx, uint64_t objectno, Extents &&image_extents,
  40                 const ZTracer::Trace &parent_trace);
  41   ~CopyupRequest();
  42
  43   void append_request(AbstractObjectWriteRequest<ImageCtxT> *req,
  44                       const Extents& object_extents);
  45
  46   void send();
  47
  48 private:
  49   /**
  50    * Copyup requests go through the following state machine to read from the
  51    * parent image, update the object map, and copyup the object:
  52    *
  53    *
  54    * @verbatim
  55    *
  56    *              <start>
  57    *                 |
  58    *      /---------/ \---------\
  59    *      |                     |
  60    *      v                     v
  61    *  READ_FROM_PARENT      DEEP_COPY
  62    *      |                     |
  63    *      \---------\ /---------/
  64    *                 |
  65    *                 v (skip if not needed)
  66    *         UPDATE_OBJECT_MAPS
  67    *                 |
  68    *                 v (skip if not needed)
  69    *              COPYUP
  70    *                 |
  71    *                 v
  72    *              <finish>
  73    *
  74    * @endverbatim
  75    *
  76    * The OBJECT_MAP state is skipped if the object map isn't enabled or if
  77    * an object map update isn't required. The COPYUP state is skipped if
  78    * no data was read from the parent *and* there are no additional ops.
  79    */
  80
  81   typedef std::vector<AbstractObjectWriteRequest<ImageCtxT> *> WriteRequests;
  82
  83   ImageCtxT *m_image_ctx;
  84   uint64_t m_object_no;
  85   Extents m_image_extents;
  86   ZTracer::Trace m_trace;
  87
  88   bool m_flatten = false;
  89   bool m_copyup_required = true;
  90   bool m_copyup_is_zero = true;
  91   bool m_deep_copied = false;
  92
  93   Extents m_copyup_extent_map;
  94   ceph::bufferlist m_copyup_data;
  95
  96   AsyncOperation m_async_op;
  97
  98   std::vector<uint64_t> m_snap_ids;
  99   bool m_first_snap_is_clean = false;
 100
 101   ceph::mutex m_lock = ceph::make_mutex("CopyupRequest", false);
 102   WriteRequests m_pending_requests;
 103   unsigned m_pending_copyups = 0;
 104   int m_copyup_ret_val = 0;
 105
 106   WriteRequests m_restart_requests;
 107   bool m_append_request_permitted = true;
 108
 109   interval_set<uint64_t> m_write_object_extents;
 110
 111   void read_from_parent();
 112   void handle_read_from_parent(int r);
 113
 114   void deep_copy();
 115   void handle_deep_copy(int r);
 116
 117   void update_object_maps();
 118   void handle_update_object_maps(int r);
 119
 120   void copyup();
 121   void handle_copyup(int r);
 122
 123   void finish(int r);
 124   void complete_requests(bool override_restart_retval, int r);
 125
 126   void disable_append_requests();
 127   void remove_from_list();
 128
 129   bool is_copyup_required();
 130   bool is_update_object_map_required(int r);
 131   bool is_deep_copy() const;
 132
 133   void compute_deep_copy_snap_ids();
 134   void convert_copyup_extent_map();
 135   int prepare_copyup_data();
 136 };
 137
 138 } // namespace io
 139 } // namespace librbd
 140
 141 extern template class librbd::io::CopyupRequest<librbd::ImageCtx>;
 142
 143 #endif // CEPH_LIBRBD_IO_COPYUP_REQUEST_H