src/ceph/src/librbd/object_map/SnapshotCreateRequest.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/object_map/SnapshotCreateRequest.h"
   5 #include "common/dout.h"
   6 #include "librbd/ImageCtx.h"
   7 #include "librbd/ObjectMap.h"
   8 #include "cls/lock/cls_lock_client.h"
   9 #include <iostream>
  10
  11 #define dout_subsys ceph_subsys_rbd
  12 #undef dout_prefix
  13 #define dout_prefix *_dout << "librbd::object_map::SnapshotCreateRequest: "
  14
  15 namespace librbd {
  16 namespace object_map {
  17
  18 namespace {
  19
  20 std::ostream& operator<<(std::ostream& os,
  21                          const SnapshotCreateRequest::State& state) {
  22   switch(state) {
  23   case SnapshotCreateRequest::STATE_READ_MAP:
  24     os << "READ_MAP";
  25     break;
  26   case SnapshotCreateRequest::STATE_WRITE_MAP:
  27     os << "WRITE_MAP";
  28     break;
  29   case SnapshotCreateRequest::STATE_ADD_SNAPSHOT:
  30     os << "ADD_SNAPSHOT";
  31     break;
  32   default:
  33     os << "UNKNOWN (" << static_cast<uint32_t>(state) << ")";
  34     break;
  35   }
  36   return os;
  37 }
  38
  39 } // anonymous namespace
  40
  41 void SnapshotCreateRequest::send() {
  42   send_read_map();
  43 }
  44
  45 bool SnapshotCreateRequest::should_complete(int r) {
  46   CephContext *cct = m_image_ctx.cct;
  47   ldout(cct, 5) << this << " " << __func__ << ": state=" << m_state << ", "
  48                 << "r=" << r << dendl;
  49   if (r < 0 && m_ret_val == 0) {
  50     m_ret_val = r;
  51   }
  52   if (m_ret_val < 0) {
  53     // pass errors down to base class to invalidate the object map
  54     return Request::should_complete(r);
  55   }
  56
  57   RWLock::RLocker owner_locker(m_image_ctx.owner_lock);
  58   bool finished = false;
  59   switch (m_state) {
  60   case STATE_READ_MAP:
  61     send_write_map();
  62     break;
  63   case STATE_WRITE_MAP:
  64     finished = send_add_snapshot();
  65     break;
  66   case STATE_ADD_SNAPSHOT:
  67     update_object_map();
  68     finished = true;
  69     break;
  70   default:
  71     assert(false);
  72     break;
  73   }
  74   return finished;
  75 }
  76
  77 void SnapshotCreateRequest::send_read_map() {
  78   assert(m_image_ctx.snap_lock.is_locked());
  79   assert(m_image_ctx.get_snap_info(m_snap_id) != NULL);
  80
  81   CephContext *cct = m_image_ctx.cct;
  82   std::string oid(ObjectMap<>::object_map_name(m_image_ctx.id, CEPH_NOSNAP));
  83   ldout(cct, 5) << this << " " << __func__ << ": oid=" << oid << dendl;
  84   m_state = STATE_READ_MAP;
  85
  86   // IO is blocked due to the snapshot creation -- consistent to read from disk
  87   librados::ObjectReadOperation op;
  88   op.read(0, 0, NULL, NULL);
  89
  90   librados::AioCompletion *rados_completion = create_callback_completion();
  91   int r = m_image_ctx.md_ctx.aio_operate(oid, rados_completion, &op,
  92                                          &m_read_bl);
  93   assert(r == 0);
  94   rados_completion->release();
  95 }
  96
  97 void SnapshotCreateRequest::send_write_map() {
  98   CephContext *cct = m_image_ctx.cct;
  99   std::string snap_oid(ObjectMap<>::object_map_name(m_image_ctx.id, m_snap_id));
 100   ldout(cct, 5) << this << " " << __func__ << ": snap_oid=" << snap_oid
 101                 << dendl;
 102   m_state = STATE_WRITE_MAP;
 103
 104   librados::ObjectWriteOperation op;
 105   op.write_full(m_read_bl);
 106
 107   librados::AioCompletion *rados_completion = create_callback_completion();
 108   int r = m_image_ctx.md_ctx.aio_operate(snap_oid, rados_completion, &op);
 109   assert(r == 0);
 110   rados_completion->release();
 111 }
 112
 113 bool SnapshotCreateRequest::send_add_snapshot() {
 114   RWLock::RLocker snap_locker(m_image_ctx.snap_lock);
 115   if ((m_image_ctx.features & RBD_FEATURE_FAST_DIFF) == 0) {
 116     return true;
 117   }
 118
 119   CephContext *cct = m_image_ctx.cct;
 120   std::string oid(ObjectMap<>::object_map_name(m_image_ctx.id, CEPH_NOSNAP));
 121   ldout(cct, 5) << this << " " << __func__ << ": oid=" << oid << dendl;
 122   m_state = STATE_ADD_SNAPSHOT;
 123
 124   librados::ObjectWriteOperation op;
 125   rados::cls::lock::assert_locked(&op, RBD_LOCK_NAME, LOCK_EXCLUSIVE, "", "");
 126   cls_client::object_map_snap_add(&op);
 127
 128   librados::AioCompletion *rados_completion = create_callback_completion();
 129   int r = m_image_ctx.md_ctx.aio_operate(oid, rados_completion, &op);
 130   assert(r == 0);
 131   rados_completion->release();
 132   return false;
 133 }
 134
 135 void SnapshotCreateRequest::update_object_map() {
 136   RWLock::WLocker snap_locker(m_image_ctx.snap_lock);
 137   RWLock::WLocker object_map_locker(m_image_ctx.object_map_lock);
 138
 139   for (uint64_t i = 0; i < m_object_map.size(); ++i) {
 140     if (m_object_map[i] == OBJECT_EXISTS) {
 141       m_object_map[i] = OBJECT_EXISTS_CLEAN;
 142     }
 143   }
 144 }
 145
 146 } // namespace object_map
 147 } // namespace librbd