ceph/src/librbd/operation/SnapshotUnprotectRequest.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/operation/SnapshotUnprotectRequest.h"
   5 #include "include/rados/librados.hpp"
   6 #include "include/stringify.h"
   7 #include "common/dout.h"
   8 #include "common/errno.h"
   9 #include "librbd/AsyncObjectThrottle.h"
  10 #include "librbd/ImageCtx.h"
  11 #include "librbd/internal.h"
  12 #include "librbd/Types.h"
  13 #include "librbd/Utils.h"
  14 #include <list>
  15 #include <set>
  16 #include <vector>
  17 #include <boost/lambda/bind.hpp>
  18 #include <boost/lambda/construct.hpp>
  19
  20 #define dout_subsys ceph_subsys_rbd
  21 #undef dout_prefix
  22 #define dout_prefix *_dout << "librbd::SnapshotUnprotectRequest: "
  23
  24 namespace librbd {
  25 namespace operation {
  26
  27 namespace {
  28
  29 typedef std::pair<int64_t, std::string> Pool;
  30 typedef std::vector<Pool> Pools;
  31
  32 template <typename I>
  33 std::ostream& operator<<(std::ostream& os,
  34                          const typename SnapshotUnprotectRequest<I>::State& state) {
  35   switch(state) {
  36   case SnapshotUnprotectRequest<I>::STATE_UNPROTECT_SNAP_START:
  37     os << "UNPROTECT_SNAP_START";
  38     break;
  39   case SnapshotUnprotectRequest<I>::STATE_SCAN_POOL_CHILDREN:
  40     os << "SCAN_POOL_CHILDREN";
  41     break;
  42   case SnapshotUnprotectRequest<I>::STATE_UNPROTECT_SNAP_FINISH:
  43     os << "UNPROTECT_SNAP_FINISH";
  44     break;
  45   case SnapshotUnprotectRequest<I>::STATE_UNPROTECT_SNAP_ROLLBACK:
  46     os << "UNPROTECT_SNAP_ROLLBACK";
  47     break;
  48   default:
  49     os << "UNKNOWN (" << static_cast<uint32_t>(state) << ")";
  50     break;
  51   }
  52   return os;
  53 }
  54
  55 template <typename I>
  56 class C_ScanPoolChildren : public C_AsyncObjectThrottle<I> {
  57 public:
  58   C_ScanPoolChildren(AsyncObjectThrottle<I> &throttle, I *image_ctx,
  59                      const ParentSpec &pspec, const Pools &pools,
  60                      size_t pool_idx)
  61     : C_AsyncObjectThrottle<I>(throttle, *image_ctx), m_pspec(pspec),
  62       m_pool(pools[pool_idx]) {
  63   }
  64
  65   int send() override {
  66     I &image_ctx = this->m_image_ctx;
  67     assert(image_ctx.owner_lock.is_locked());
  68
  69     CephContext *cct = image_ctx.cct;
  70     ldout(cct, 10) << this << " scanning pool '" << m_pool.second << "'"
  71                    << dendl;
  72
  73     librados::Rados rados(image_ctx.md_ctx);
  74     int64_t base_tier;
  75     int r = rados.pool_get_base_tier(m_pool.first, &base_tier);
  76     if (r == -ENOENT) {
  77       ldout(cct, 1) << "pool '" << m_pool.second << "' no longer exists"
  78                     << dendl;
  79       return 1;
  80     } else if (r < 0) {
  81       lderr(cct) << "error retrieving base tier for pool '"
  82                  << m_pool.second << "'" << dendl;
  83       return r;
  84     }
  85     if (m_pool.first != base_tier) {
  86       // pool is a cache; skip it
  87       return 1;
  88     }
  89
  90     r = rados.ioctx_create2(m_pool.first, m_pool_ioctx);
  91     if (r == -ENOENT) {
  92       ldout(cct, 1) << "pool '" << m_pool.second << "' no longer exists"
  93                     << dendl;
  94       return 1;
  95     } else if (r < 0) {
  96       lderr(cct) << "can't create ioctx for pool '" << m_pool.second
  97                  << "'" << dendl;
  98       return r;
  99     }
 100
 101     librados::ObjectReadOperation op;
 102     cls_client::get_children_start(&op, m_pspec);
 103
 104     librados::AioCompletion *rados_completion =
 105       util::create_rados_callback(this);
 106     r = m_pool_ioctx.aio_operate(RBD_CHILDREN, rados_completion, &op,
 107                                  &m_children_bl);
 108     assert(r == 0);
 109     rados_completion->release();
 110     return 0;
 111   }
 112
 113 protected:
 114   void finish(int r) override {
 115     I &image_ctx = this->m_image_ctx;
 116     CephContext *cct = image_ctx.cct;
 117
 118     if (r == 0) {
 119       bufferlist::iterator it = m_children_bl.begin();
 120       r= cls_client::get_children_finish(&it, &m_children);
 121     }
 122
 123     ldout(cct, 10) << this << " retrieved children: r=" << r << dendl;
 124     if (r == -ENOENT) {
 125       // no children -- proceed with unprotect
 126       r = 0;
 127     } else if (r < 0) {
 128       lderr(cct) << "cannot get children for pool '" << m_pool.second << "'"
 129                  << dendl;
 130     } else {
 131       lderr(cct) << "cannot unprotect: at least " << m_children.size() << " "
 132                  << "child(ren) [" << joinify(m_children.begin(),
 133                                               m_children.end(),
 134                                               std::string(",")) << "] "
 135                  << "in pool '" << m_pool.second << "'" << dendl;
 136       r = -EBUSY;
 137     }
 138     C_AsyncObjectThrottle<I>::finish(r);
 139   }
 140
 141 private:
 142   ParentSpec m_pspec;
 143   Pool m_pool;
 144
 145   IoCtx m_pool_ioctx;
 146   std::set<std::string> m_children;
 147   bufferlist m_children_bl;
 148 };
 149
 150 } // anonymous namespace
 151
 152 template <typename I>
 153 SnapshotUnprotectRequest<I>::SnapshotUnprotectRequest(I &image_ctx,
 154                                                       Context *on_finish,
 155                                                       const cls::rbd::SnapshotNamespace &snap_namespace,
 156                                                       const std::string &snap_name)
 157   : Request<I>(image_ctx, on_finish), m_snap_namespace(snap_namespace),
 158     m_snap_name(snap_name), m_ret_val(0), m_snap_id(CEPH_NOSNAP) {
 159 }
 160
 161 template <typename I>
 162 void SnapshotUnprotectRequest<I>::send_op() {
 163   send_unprotect_snap_start();
 164 }
 165
 166 template <typename I>
 167 bool SnapshotUnprotectRequest<I>::should_complete(int r) {
 168   I &image_ctx = this->m_image_ctx;
 169   CephContext *cct = image_ctx.cct;
 170   ldout(cct, 5) << this << " " << __func__ << ": state=" << m_state << ", "
 171                 << "r=" << r << dendl;
 172   if (r < 0) {
 173     if (r == -EINVAL) {
 174       ldout(cct, 1) << "snapshot is already unprotected" << dendl;
 175     } else {
 176       lderr(cct) << "encountered error: " << cpp_strerror(r) << dendl;
 177     }
 178     if (m_ret_val == 0) {
 179       m_ret_val = r;
 180     }
 181   }
 182
 183   // use a different state machine once an error is encountered
 184   if (m_ret_val < 0) {
 185     return should_complete_error();
 186   }
 187
 188   RWLock::RLocker owner_lock(image_ctx.owner_lock);
 189   bool finished = false;
 190   switch (m_state) {
 191   case STATE_UNPROTECT_SNAP_START:
 192     send_scan_pool_children();
 193     break;
 194   case STATE_SCAN_POOL_CHILDREN:
 195     send_unprotect_snap_finish();
 196     break;
 197   case STATE_UNPROTECT_SNAP_FINISH:
 198     finished = true;
 199     break;
 200   default:
 201     assert(false);
 202     break;
 203   }
 204   return finished;
 205 }
 206
 207 template <typename I>
 208 bool SnapshotUnprotectRequest<I>::should_complete_error() {
 209   I &image_ctx = this->m_image_ctx;
 210   RWLock::RLocker owner_locker(image_ctx.owner_lock);
 211   CephContext *cct = image_ctx.cct;
 212   lderr(cct) << this << " " << __func__ << ": "
 213              << "ret_val=" << m_ret_val << dendl;
 214
 215   bool finished = true;
 216   if (m_state == STATE_SCAN_POOL_CHILDREN ||
 217       m_state == STATE_UNPROTECT_SNAP_FINISH) {
 218     send_unprotect_snap_rollback();
 219     finished = false;
 220   }
 221   return finished;
 222 }
 223
 224 template <typename I>
 225 void SnapshotUnprotectRequest<I>::send_unprotect_snap_start() {
 226   I &image_ctx = this->m_image_ctx;
 227   assert(image_ctx.owner_lock.is_locked());
 228
 229   CephContext *cct = image_ctx.cct;
 230   ldout(cct, 5) << this << " " << __func__ << dendl;
 231
 232   m_state = STATE_UNPROTECT_SNAP_START;
 233
 234   int r = verify_and_send_unprotect_snap_start();
 235   if (r < 0) {
 236     this->async_complete(r);
 237     return;
 238   }
 239 }
 240
 241 template <typename I>
 242 void SnapshotUnprotectRequest<I>::send_scan_pool_children() {
 243   I &image_ctx = this->m_image_ctx;
 244   assert(image_ctx.owner_lock.is_locked());
 245
 246   CephContext *cct = image_ctx.cct;
 247   ldout(cct, 5) << this << " " << __func__ << dendl;
 248   m_state = STATE_SCAN_POOL_CHILDREN;
 249
 250   // search all pools for children depending on this snapshot
 251   // TODO add async version of wait_for_latest_osdmap
 252   librados::Rados rados(image_ctx.md_ctx);
 253   rados.wait_for_latest_osdmap();
 254
 255   // protect against pools being renamed/deleted
 256   std::list<Pool> pool_list;
 257   rados.pool_list2(pool_list);
 258
 259   ParentSpec pspec(image_ctx.md_ctx.get_id(), image_ctx.id, m_snap_id);
 260   Pools pools(pool_list.begin(), pool_list.end());
 261
 262   Context *ctx = this->create_callback_context();
 263   typename AsyncObjectThrottle<I>::ContextFactory context_factory(
 264     boost::lambda::bind(boost::lambda::new_ptr<C_ScanPoolChildren<I> >(),
 265       boost::lambda::_1, &image_ctx, pspec, pools, boost::lambda::_2));
 266   AsyncObjectThrottle<I> *throttle = new AsyncObjectThrottle<I>(
 267     nullptr, image_ctx, context_factory, ctx, NULL, 0, pools.size());
 268   throttle->start_ops(image_ctx.concurrent_management_ops);
 269 }
 270
 271 template <typename I>
 272 void SnapshotUnprotectRequest<I>::send_unprotect_snap_finish() {
 273   I &image_ctx = this->m_image_ctx;
 274   assert(image_ctx.owner_lock.is_locked());
 275
 276   CephContext *cct = image_ctx.cct;
 277   ldout(cct, 5) << this << " " << __func__ << dendl;
 278
 279   m_state = STATE_UNPROTECT_SNAP_FINISH;
 280
 281   librados::ObjectWriteOperation op;
 282   cls_client::set_protection_status(&op, m_snap_id,
 283                                     RBD_PROTECTION_STATUS_UNPROTECTED);
 284
 285   librados::AioCompletion *comp = this->create_callback_completion();
 286   int r = image_ctx.md_ctx.aio_operate(image_ctx.header_oid, comp, &op);
 287   assert(r == 0);
 288   comp->release();
 289 }
 290
 291 template <typename I>
 292 void SnapshotUnprotectRequest<I>::send_unprotect_snap_rollback() {
 293   I &image_ctx = this->m_image_ctx;
 294   assert(image_ctx.owner_lock.is_locked());
 295
 296   CephContext *cct = image_ctx.cct;
 297   ldout(cct, 5) << this << " " << __func__ << dendl;
 298
 299   m_state = STATE_UNPROTECT_SNAP_ROLLBACK;
 300
 301   librados::ObjectWriteOperation op;
 302   cls_client::set_protection_status(&op, m_snap_id,
 303                                     RBD_PROTECTION_STATUS_PROTECTED);
 304
 305   librados::AioCompletion *comp = this->create_callback_completion();
 306   int r = image_ctx.md_ctx.aio_operate(image_ctx.header_oid, comp, &op);
 307   assert(r == 0);
 308   comp->release();
 309 }
 310
 311 template <typename I>
 312 int SnapshotUnprotectRequest<I>::verify_and_send_unprotect_snap_start() {
 313   I &image_ctx = this->m_image_ctx;
 314   RWLock::RLocker md_locker(image_ctx.md_lock);
 315   RWLock::RLocker snap_locker(image_ctx.snap_lock);
 316
 317   CephContext *cct = image_ctx.cct;
 318   if ((image_ctx.features & RBD_FEATURE_LAYERING) == 0) {
 319     lderr(cct) << "image must support layering" << dendl;
 320     return -ENOSYS;
 321   }
 322
 323   m_snap_id = image_ctx.get_snap_id(m_snap_namespace, m_snap_name);
 324   if (m_snap_id == CEPH_NOSNAP) {
 325     return -ENOENT;
 326   }
 327
 328   bool is_unprotected;
 329   int r = image_ctx.is_snap_unprotected(m_snap_id, &is_unprotected);
 330   if (r < 0) {
 331     return r;
 332   }
 333
 334   if (is_unprotected) {
 335     lderr(cct) << "snapshot is already unprotected" << dendl;
 336     return -EINVAL;
 337   }
 338
 339   librados::ObjectWriteOperation op;
 340   cls_client::set_protection_status(&op, m_snap_id,
 341                                     RBD_PROTECTION_STATUS_UNPROTECTING);
 342
 343   librados::AioCompletion *comp = this->create_callback_completion();
 344   r = image_ctx.md_ctx.aio_operate(image_ctx.header_oid, comp, &op);
 345   assert(r == 0);
 346   comp->release();
 347
 348   // TODO legacy code threw a notification post UNPROTECTING update -- required?
 349   return 0;
 350 }
 351
 352 } // namespace operation
 353 } // namespace librbd
 354
 355 template class librbd::operation::SnapshotUnprotectRequest<librbd::ImageCtx>;