ceph/src/librbd/image/GetMetadataRequest.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/image/GetMetadataRequest.h"
   5 #include "cls/rbd/cls_rbd_client.h"
   6 #include "common/dout.h"
   7 #include "common/errno.h"
   8 #include "include/ceph_assert.h"
   9 #include "librbd/ImageCtx.h"
  10 #include "librbd/Utils.h"
  11 #include <boost/algorithm/string/predicate.hpp>
  12
  13 #define dout_subsys ceph_subsys_rbd
  14 #undef dout_prefix
  15 #define dout_prefix *_dout << "librbd::image::GetMetadataRequest: " \
  16                            << this << " " << __func__ << ": "
  17
  18 #define MAX_KEYS 64U
  19
  20 namespace librbd {
  21 namespace image {
  22 namespace {
  23
  24 static const std::string INTERNAL_KEY_PREFIX{".rbd"};
  25
  26 } // anonymous namespace
  27
  28 using util::create_rados_callback;
  29
  30 template <typename I>
  31 GetMetadataRequest<I>::GetMetadataRequest(
  32     IoCtx &io_ctx, const std::string &oid, bool filter_internal,
  33     const std::string& filter_key_prefix, const std::string& last_key,
  34     uint32_t max_results, KeyValues* key_values, Context *on_finish)
  35   : m_io_ctx(io_ctx), m_oid(oid), m_filter_internal(filter_internal),
  36     m_filter_key_prefix(filter_key_prefix), m_last_key(last_key),
  37     m_max_results(max_results), m_key_values(key_values),
  38     m_on_finish(on_finish),
  39     m_cct(reinterpret_cast<CephContext*>(m_io_ctx.cct())) {
  40 }
  41
  42 template <typename I>
  43 void GetMetadataRequest<I>::send() {
  44   metadata_list();
  45 }
  46
  47 template <typename I>
  48 void GetMetadataRequest<I>::metadata_list() {
  49   ldout(m_cct, 15) << "start_key=" << m_last_key << dendl;
  50
  51   m_expected_results = MAX_KEYS;
  52   if (m_max_results > 0) {
  53     m_expected_results = std::min<uint32_t>(
  54       m_expected_results, m_max_results - m_key_values->size());
  55   }
  56
  57   librados::ObjectReadOperation op;
  58   cls_client::metadata_list_start(&op, m_last_key, m_expected_results);
  59
  60   auto aio_comp = create_rados_callback<
  61     GetMetadataRequest<I>, &GetMetadataRequest<I>::handle_metadata_list>(this);
  62   m_out_bl.clear();
  63   m_io_ctx.aio_operate(m_oid, aio_comp, &op, &m_out_bl);
  64   aio_comp->release();
  65 }
  66
  67 template <typename I>
  68 void GetMetadataRequest<I>::handle_metadata_list(int r) {
  69   ldout(m_cct, 15) << "r=" << r << dendl;
  70
  71   KeyValues metadata;
  72   if (r == 0) {
  73     auto it = m_out_bl.cbegin();
  74     r = cls_client::metadata_list_finish(&it, &metadata);
  75   }
  76
  77   if (r == -ENOENT || r == -EOPNOTSUPP) {
  78     finish(0);
  79     return;
  80   } else if (r < 0) {
  81     lderr(m_cct) << "failed to retrieve image metadata: " << cpp_strerror(r)
  82                  << dendl;
  83     finish(r);
  84     return;
  85   }
  86
  87   for (auto it = metadata.begin(); it != metadata.end(); ++it) {
  88     if (m_filter_internal &&
  89         boost::starts_with(it->first, INTERNAL_KEY_PREFIX)) {
  90       continue;
  91     } else if (!m_filter_key_prefix.empty() &&
  92                !boost::starts_with(it->first, m_filter_key_prefix)) {
  93       continue;
  94     }
  95     m_key_values->insert({it->first, std::move(it->second)});
  96   }
  97   if (!metadata.empty()) {
  98     m_last_key = metadata.rbegin()->first;
  99   }
 100
 101   if (metadata.size() == m_expected_results &&
 102       (m_max_results == 0 || m_key_values->size() < m_max_results)) {
 103     metadata_list();
 104     return;
 105   }
 106
 107   finish(0);
 108 }
 109
 110 template <typename I>
 111 void GetMetadataRequest<I>::finish(int r) {
 112   ldout(m_cct, 15) << "r=" << r << dendl;
 113
 114   m_on_finish->complete(r);
 115   delete this;
 116 }
 117
 118 } // namespace image
 119 } // namespace librbd
 120
 121 template class librbd::image::GetMetadataRequest<librbd::ImageCtx>;