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
  80   CephContext *cct = m_image_ctx.cct;
  81   std::string oid(ObjectMap<>::object_map_name(m_image_ctx.id, CEPH_NOSNAP));
  82   ldout(cct, 5) << this << " " << __func__ << ": oid=" << oid << dendl;
  83   m_state = STATE_READ_MAP;
  84
  85   // IO is blocked due to the snapshot creation -- consistent to read from disk
  86   librados::ObjectReadOperation op;
  87   op.read(0, 0, NULL, NULL);
  88
  89   librados::AioCompletion *rados_completion = create_callback_completion();
  90   int r = m_image_ctx.md_ctx.aio_operate(oid, rados_completion, &op,
  91                                          &m_read_bl);
  92   assert(r == 0);
  93   rados_completion->release();
  94 }
  95
  96 void SnapshotCreateRequest::send_write_map() {
  97   CephContext *cct = m_image_ctx.cct;
  98   std::string snap_oid(ObjectMap<>::object_map_name(m_image_ctx.id, m_snap_id));
  99   ldout(cct, 5) << this << " " << __func__ << ": snap_oid=" << snap_oid
 100                 << dendl;
 101   m_state = STATE_WRITE_MAP;
 102
 103   librados::ObjectWriteOperation op;
 104   op.write_full(m_read_bl);
 105
 106   librados::AioCompletion *rados_completion = create_callback_completion();
 107   int r = m_image_ctx.md_ctx.aio_operate(snap_oid, rados_completion, &op);
 108   assert(r == 0);
 109   rados_completion->release();
 110 }
 111
 112 bool SnapshotCreateRequest::send_add_snapshot() {
 113   RWLock::RLocker snap_locker(m_image_ctx.snap_lock);
 114   if ((m_image_ctx.features & RBD_FEATURE_FAST_DIFF) == 0) {
 115     return true;
 116   }
 117
 118   CephContext *cct = m_image_ctx.cct;
 119   std::string oid(ObjectMap<>::object_map_name(m_image_ctx.id, CEPH_NOSNAP));
 120   ldout(cct, 5) << this << " " << __func__ << ": oid=" << oid << dendl;
 121   m_state = STATE_ADD_SNAPSHOT;
 122
 123   librados::ObjectWriteOperation op;
 124   rados::cls::lock::assert_locked(&op, RBD_LOCK_NAME, LOCK_EXCLUSIVE, "", "");
 125   cls_client::object_map_snap_add(&op);
 126
 127   librados::AioCompletion *rados_completion = create_callback_completion();
 128   int r = m_image_ctx.md_ctx.aio_operate(oid, rados_completion, &op);
 129   assert(r == 0);
 130   rados_completion->release();
 131   return false;
 132 }
 133
 134 void SnapshotCreateRequest::update_object_map() {
 135   RWLock::WLocker snap_locker(m_image_ctx.snap_lock);
 136   RWLock::WLocker object_map_locker(m_image_ctx.object_map_lock);
 137
 138   auto it = m_object_map.begin();
 139   auto end_it = m_object_map.end();
 140   for (; it != end_it; ++it) {
 141     if (*it == OBJECT_EXISTS) {
 142       *it = OBJECT_EXISTS_CLEAN;
 143     }
 144   }
 145 }
 146
 147 } // namespace object_map
 148 } // namespace librbd