ceph/src/librbd/mirror/snapshot/GetImageStateRequest.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 "librbd/mirror/snapshot/GetImageStateRequest.h"
   5 #include "common/dout.h"
   6 #include "common/errno.h"
   7 #include "librbd/ImageCtx.h"
   8 #include "librbd/Utils.h"
   9 #include "librbd/mirror/snapshot/Types.h"
  10 #include "librbd/mirror/snapshot/Utils.h"
  11
  12 #define dout_subsys ceph_subsys_rbd
  13
  14 #undef dout_prefix
  15 #define dout_prefix *_dout << "librbd::mirror::snapshot::GetImageStateRequest: " \
  16                            << this << " " << __func__ << ": "
  17
  18 namespace librbd {
  19 namespace mirror {
  20 namespace snapshot {
  21
  22 using librbd::util::create_rados_callback;
  23
  24 template <typename I>
  25 void GetImageStateRequest<I>::send() {
  26   read_object();
  27 }
  28
  29
  30 template <typename I>
  31 void GetImageStateRequest<I>::read_object() {
  32   CephContext *cct = m_image_ctx->cct;
  33
  34   auto oid = util::image_state_object_name(m_image_ctx, m_snap_id,
  35                                            m_object_index);
  36   ldout(cct, 20) << oid << dendl;
  37
  38   librados::ObjectReadOperation op;
  39   m_bl.clear();
  40   op.read(0, 0, &m_bl, nullptr);
  41
  42   librados::AioCompletion *comp = create_rados_callback<
  43     GetImageStateRequest<I>,
  44     &GetImageStateRequest<I>::handle_read_object>(this);
  45   int r = m_image_ctx->md_ctx.aio_operate(oid, comp, &op, nullptr);
  46   ceph_assert(r == 0);
  47   comp->release();
  48 }
  49
  50 template <typename I>
  51 void GetImageStateRequest<I>::handle_read_object(int r) {
  52   CephContext *cct = m_image_ctx->cct;
  53   ldout(cct, 20) << "r=" << r << dendl;
  54
  55   if (r < 0) {
  56     lderr(cct) << "failed to read image state object: " << cpp_strerror(r)
  57                << dendl;
  58     finish(r);
  59     return;
  60   }
  61
  62   auto iter = m_bl.cbegin();
  63
  64   if (m_object_index == 0) {
  65     ImageStateHeader header;
  66     try {
  67       using ceph::decode;
  68       decode(header, iter);
  69     } catch (const buffer::error &err) {
  70       lderr(cct) << "failed to decode image state object header" << dendl;
  71       finish(-EBADMSG);
  72       return;
  73     }
  74     m_object_count = header.object_count;
  75   }
  76
  77   bufferlist bl;
  78   bl.substr_of(m_bl, iter.get_off(), m_bl.length() - iter.get_off());
  79   m_state_bl.claim_append(bl);
  80
  81   m_object_index++;
  82
  83   if (m_object_index >= m_object_count) {
  84     finish(0);
  85     return;
  86   }
  87
  88   read_object();
  89 }
  90
  91 template <typename I>
  92 void GetImageStateRequest<I>::finish(int r) {
  93   CephContext *cct = m_image_ctx->cct;
  94   ldout(cct, 20) << "r=" << r << dendl;
  95
  96   if (r == 0) {
  97     try {
  98       using ceph::decode;
  99       decode(*m_image_state, m_state_bl);
 100     } catch (const buffer::error &err) {
 101       lderr(cct) << "failed to decode image state" << dendl;
 102       r = -EBADMSG;
 103     }
 104   }
 105
 106   m_on_finish->complete(r);
 107   delete this;
 108 }
 109
 110 } // namespace snapshot
 111 } // namespace mirror
 112 } // namespace librbd
 113
 114 template class librbd::mirror::snapshot::GetImageStateRequest<librbd::ImageCtx>;