ceph/src/librbd/io/CopyupRequest.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/io/CopyupRequest.h"
   5 #include "common/ceph_context.h"
   6 #include "common/dout.h"
   7 #include "common/errno.h"
   8 #include "common/Mutex.h"
   9 #include "common/WorkQueue.h"
  10 #include "librbd/AsyncObjectThrottle.h"
  11 #include "librbd/ExclusiveLock.h"
  12 #include "librbd/ImageCtx.h"
  13 #include "librbd/ObjectMap.h"
  14 #include "librbd/Utils.h"
  15 #include "librbd/deep_copy/ObjectCopyRequest.h"
  16 #include "librbd/io/AioCompletion.h"
  17 #include "librbd/io/ImageRequest.h"
  18 #include "librbd/io/ObjectRequest.h"
  19 #include "librbd/io/ReadResult.h"
  20
  21 #include <boost/bind.hpp>
  22 #include <boost/lambda/bind.hpp>
  23 #include <boost/lambda/construct.hpp>
  24
  25 #define dout_subsys ceph_subsys_rbd
  26 #undef dout_prefix
  27 #define dout_prefix *_dout << "librbd::io::CopyupRequest: " << this \
  28                            << " " << __func__ << ": "
  29
  30 namespace librbd {
  31 namespace io {
  32
  33 namespace {
  34
  35 template <typename I>
  36 class C_UpdateObjectMap : public C_AsyncObjectThrottle<I> {
  37 public:
  38   C_UpdateObjectMap(AsyncObjectThrottle<I> &throttle, I *image_ctx,
  39                     uint64_t object_no, uint8_t head_object_map_state,
  40                     const std::vector<uint64_t> *snap_ids,
  41                     bool first_snap_is_clean, const ZTracer::Trace &trace,
  42                     size_t snap_id_idx)
  43     : C_AsyncObjectThrottle<I>(throttle, *image_ctx), m_object_no(object_no),
  44       m_head_object_map_state(head_object_map_state), m_snap_ids(*snap_ids),
  45       m_first_snap_is_clean(first_snap_is_clean), m_trace(trace),
  46       m_snap_id_idx(snap_id_idx)
  47   {
  48   }
  49
  50   int send() override {
  51     auto& image_ctx = this->m_image_ctx;
  52     ceph_assert(image_ctx.owner_lock.is_locked());
  53     if (image_ctx.exclusive_lock == nullptr) {
  54       return 1;
  55     }
  56     ceph_assert(image_ctx.exclusive_lock->is_lock_owner());
  57
  58     RWLock::RLocker snap_locker(image_ctx.snap_lock);
  59     if (image_ctx.object_map == nullptr) {
  60       return 1;
  61     }
  62
  63     uint64_t snap_id = m_snap_ids[m_snap_id_idx];
  64     if (snap_id == CEPH_NOSNAP) {
  65       return update_head();
  66     } else {
  67       return update_snapshot(snap_id);
  68     }
  69   }
  70
  71   int update_head() {
  72     auto& image_ctx = this->m_image_ctx;
  73     RWLock::WLocker object_map_locker(image_ctx.object_map_lock);
  74     bool sent = image_ctx.object_map->template aio_update<Context>(
  75       CEPH_NOSNAP, m_object_no, m_head_object_map_state, {}, m_trace, false,
  76       this);
  77     return (sent ? 0 : 1);
  78   }
  79
  80   int update_snapshot(uint64_t snap_id) {
  81     auto& image_ctx = this->m_image_ctx;
  82     uint8_t state = OBJECT_EXISTS;
  83     if (image_ctx.test_features(RBD_FEATURE_FAST_DIFF, image_ctx.snap_lock) &&
  84         (m_snap_id_idx > 0 || m_first_snap_is_clean)) {
  85       // first snapshot should be exists+dirty since it contains
  86       // the copyup data -- later snapshots inherit the data.
  87       state = OBJECT_EXISTS_CLEAN;
  88     }
  89
  90     RWLock::RLocker object_map_locker(image_ctx.object_map_lock);
  91     bool sent = image_ctx.object_map->template aio_update<Context>(
  92       snap_id, m_object_no, state, {}, m_trace, true, this);
  93     ceph_assert(sent);
  94     return 0;
  95   }
  96
  97 private:
  98   uint64_t m_object_no;
  99   uint8_t m_head_object_map_state;
 100   const std::vector<uint64_t> &m_snap_ids;
 101   bool m_first_snap_is_clean;
 102   const ZTracer::Trace &m_trace;
 103   size_t m_snap_id_idx;
 104 };
 105
 106 } // anonymous namespace
 107
 108 template <typename I>
 109 CopyupRequest<I>::CopyupRequest(I *ictx, const std::string &oid,
 110                                 uint64_t objectno, Extents &&image_extents,
 111                                 const ZTracer::Trace &parent_trace)
 112   : m_image_ctx(ictx), m_oid(oid), m_object_no(objectno),
 113     m_image_extents(image_extents),
 114     m_trace(util::create_trace(*m_image_ctx, "copy-up", parent_trace)),
 115     m_lock("CopyupRequest", false, false)
 116 {
 117   m_async_op.start_op(*util::get_image_ctx(m_image_ctx));
 118 }
 119
 120 template <typename I>
 121 CopyupRequest<I>::~CopyupRequest() {
 122   ceph_assert(m_pending_requests.empty());
 123   m_async_op.finish_op();
 124 }
 125
 126 template <typename I>
 127 void CopyupRequest<I>::append_request(AbstractObjectWriteRequest<I> *req) {
 128   Mutex::Locker locker(m_lock);
 129
 130   auto cct = m_image_ctx->cct;
 131   ldout(cct, 20) << "oid=" << m_oid << ", "
 132                  << "object_request=" << req << ", "
 133                  << "append=" << m_append_request_permitted << dendl;
 134   if (m_append_request_permitted) {
 135     m_pending_requests.push_back(req);
 136   } else {
 137     m_restart_requests.push_back(req);
 138   }
 139 }
 140
 141 template <typename I>
 142 void CopyupRequest<I>::send() {
 143   read_from_parent();
 144 }
 145
 146 template <typename I>
 147 void CopyupRequest<I>::read_from_parent() {
 148   auto cct = m_image_ctx->cct;
 149   RWLock::RLocker snap_locker(m_image_ctx->snap_lock);
 150   RWLock::RLocker parent_locker(m_image_ctx->parent_lock);
 151
 152   if (m_image_ctx->parent == nullptr) {
 153     ldout(cct, 5) << "parent detached" << dendl;
 154
 155     m_image_ctx->op_work_queue->queue(
 156       util::create_context_callback<
 157         CopyupRequest<I>, &CopyupRequest<I>::handle_read_from_parent>(this),
 158       -ENOENT);
 159     return;
 160   } else if (is_deep_copy()) {
 161     deep_copy();
 162     return;
 163   }
 164
 165   auto comp = AioCompletion::create_and_start<
 166     CopyupRequest<I>,
 167     &CopyupRequest<I>::handle_read_from_parent>(
 168       this, util::get_image_ctx(m_image_ctx->parent), AIO_TYPE_READ);
 169
 170   ldout(cct, 20) << "oid=" << m_oid << ", "
 171                  << "completion=" << comp << ", "
 172                  << "extents=" << m_image_extents
 173                  << dendl;
 174   ImageRequest<I>::aio_read(m_image_ctx->parent, comp,
 175                             std::move(m_image_extents),
 176                             ReadResult{&m_copyup_data}, 0, m_trace);
 177 }
 178
 179 template <typename I>
 180 void CopyupRequest<I>::handle_read_from_parent(int r) {
 181   auto cct = m_image_ctx->cct;
 182   ldout(cct, 20) << "oid=" << m_oid << ", r=" << r << dendl;
 183
 184   m_image_ctx->snap_lock.get_read();
 185   m_lock.Lock();
 186   m_copyup_is_zero = m_copyup_data.is_zero();
 187   m_copyup_required = is_copyup_required();
 188   disable_append_requests();
 189
 190   if (r < 0 && r != -ENOENT) {
 191     m_lock.Unlock();
 192     m_image_ctx->snap_lock.put_read();
 193
 194     lderr(cct) << "error reading from parent: " << cpp_strerror(r) << dendl;
 195     finish(r);
 196     return;
 197   }
 198
 199   if (!m_copyup_required) {
 200     m_lock.Unlock();
 201     m_image_ctx->snap_lock.put_read();
 202
 203     ldout(cct, 20) << "no-op, skipping" << dendl;
 204     finish(0);
 205     return;
 206   }
 207
 208   // copyup() will affect snapshots only if parent data is not all
 209   // zeros.
 210   if (!m_copyup_is_zero) {
 211     m_snap_ids.insert(m_snap_ids.end(), m_image_ctx->snaps.rbegin(),
 212                       m_image_ctx->snaps.rend());
 213   }
 214
 215   m_lock.Unlock();
 216   m_image_ctx->snap_lock.put_read();
 217
 218   update_object_maps();
 219 }
 220
 221 template <typename I>
 222 void CopyupRequest<I>::deep_copy() {
 223   auto cct = m_image_ctx->cct;
 224   ceph_assert(m_image_ctx->snap_lock.is_locked());
 225   ceph_assert(m_image_ctx->parent_lock.is_locked());
 226   ceph_assert(m_image_ctx->parent != nullptr);
 227
 228   m_lock.Lock();
 229   m_flatten = is_copyup_required() ? true : m_image_ctx->migration_info.flatten;
 230   m_lock.Unlock();
 231
 232   ldout(cct, 20) << "oid=" << m_oid << ", flatten=" << m_flatten << dendl;
 233
 234   auto ctx = util::create_context_callback<
 235     CopyupRequest<I>, &CopyupRequest<I>::handle_deep_copy>(this);
 236   auto req = deep_copy::ObjectCopyRequest<I>::create(
 237     m_image_ctx->parent, m_image_ctx, m_image_ctx->migration_info.snap_map,
 238     m_object_no, m_flatten, ctx);
 239
 240   req->send();
 241 }
 242
 243 template <typename I>
 244 void CopyupRequest<I>::handle_deep_copy(int r) {
 245   auto cct = m_image_ctx->cct;
 246   ldout(cct, 20) << "oid=" << m_oid << ", r=" << r << dendl;
 247
 248   m_image_ctx->snap_lock.get_read();
 249   m_lock.Lock();
 250   m_copyup_required = is_copyup_required();
 251   if (r == -ENOENT && !m_flatten && m_copyup_required) {
 252     m_lock.Unlock();
 253     m_image_ctx->snap_lock.put_read();
 254
 255     ldout(cct, 10) << "restart deep-copy with flatten" << dendl;
 256     send();
 257     return;
 258   }
 259
 260   disable_append_requests();
 261
 262   if (r < 0 && r != -ENOENT) {
 263     m_lock.Unlock();
 264     m_image_ctx->snap_lock.put_read();
 265
 266     lderr(cct) << "error encountered during deep-copy: " << cpp_strerror(r)
 267                << dendl;
 268     finish(r);
 269     return;
 270   }
 271
 272   if (!m_copyup_required && !is_update_object_map_required(r)) {
 273     m_lock.Unlock();
 274     m_image_ctx->snap_lock.put_read();
 275
 276     if (r == -ENOENT) {
 277       r = 0;
 278     }
 279
 280     ldout(cct, 20) << "skipping" << dendl;
 281     finish(r);
 282     return;
 283   }
 284
 285   // For deep-copy, copyup() will never affect snapshots.  However,
 286   // this state machine is responsible for updating object maps for
 287   // snapshots that have been created on destination image after
 288   // migration started.
 289   if (r != -ENOENT) {
 290     compute_deep_copy_snap_ids();
 291   }
 292
 293   m_lock.Unlock();
 294   m_image_ctx->snap_lock.put_read();
 295
 296   update_object_maps();
 297 }
 298
 299 template <typename I>
 300 void CopyupRequest<I>::update_object_maps() {
 301   RWLock::RLocker owner_locker(m_image_ctx->owner_lock);
 302   RWLock::RLocker snap_locker(m_image_ctx->snap_lock);
 303   if (m_image_ctx->object_map == nullptr) {
 304     snap_locker.unlock();
 305     owner_locker.unlock();
 306
 307     copyup();
 308     return;
 309   }
 310
 311   auto cct = m_image_ctx->cct;
 312   ldout(cct, 20) << "oid=" << m_oid << dendl;
 313
 314   bool copy_on_read = m_pending_requests.empty();
 315   uint8_t head_object_map_state = OBJECT_EXISTS;
 316   if (copy_on_read && !m_snap_ids.empty() &&
 317       m_image_ctx->test_features(RBD_FEATURE_FAST_DIFF,
 318                                  m_image_ctx->snap_lock)) {
 319     // HEAD is non-dirty since data is tied to first snapshot
 320     head_object_map_state = OBJECT_EXISTS_CLEAN;
 321   }
 322
 323   auto r_it = m_pending_requests.rbegin();
 324   if (r_it != m_pending_requests.rend()) {
 325     // last write-op determines the final object map state
 326     head_object_map_state = (*r_it)->get_pre_write_object_map_state();
 327   }
 328
 329   RWLock::WLocker object_map_locker(m_image_ctx->object_map_lock);
 330   if ((*m_image_ctx->object_map)[m_object_no] != head_object_map_state) {
 331     // (maybe) need to update the HEAD object map state
 332     m_snap_ids.push_back(CEPH_NOSNAP);
 333   }
 334   object_map_locker.unlock();
 335   snap_locker.unlock();
 336
 337   ceph_assert(m_image_ctx->exclusive_lock->is_lock_owner());
 338   typename AsyncObjectThrottle<I>::ContextFactory context_factory(
 339     boost::lambda::bind(boost::lambda::new_ptr<C_UpdateObjectMap<I>>(),
 340     boost::lambda::_1, m_image_ctx, m_object_no, head_object_map_state,
 341     &m_snap_ids, m_first_snap_is_clean, m_trace, boost::lambda::_2));
 342   auto ctx = util::create_context_callback<
 343     CopyupRequest<I>, &CopyupRequest<I>::handle_update_object_maps>(this);
 344   auto throttle = new AsyncObjectThrottle<I>(
 345     nullptr, *m_image_ctx, context_factory, ctx, nullptr, 0, m_snap_ids.size());
 346   throttle->start_ops(
 347     m_image_ctx->config.template get_val<uint64_t>("rbd_concurrent_management_ops"));
 348 }
 349
 350 template <typename I>
 351 void CopyupRequest<I>::handle_update_object_maps(int r) {
 352   auto cct = m_image_ctx->cct;
 353   ldout(cct, 20) << "oid=" << m_oid << ", r=" << r << dendl;
 354
 355   if (r < 0) {
 356     lderr(m_image_ctx->cct) << "failed to update object map: "
 357                             << cpp_strerror(r) << dendl;
 358
 359     finish(r);
 360     return;
 361   }
 362
 363   copyup();
 364 }
 365
 366 template <typename I>
 367 void CopyupRequest<I>::copyup() {
 368   auto cct = m_image_ctx->cct;
 369   m_image_ctx->snap_lock.get_read();
 370   auto snapc = m_image_ctx->snapc;
 371   m_image_ctx->snap_lock.put_read();
 372
 373   m_lock.Lock();
 374   if (!m_copyup_required) {
 375     m_lock.Unlock();
 376
 377     ldout(cct, 20) << "skipping copyup" << dendl;
 378     finish(0);
 379     return;
 380   }
 381
 382   ldout(cct, 20) << "oid=" << m_oid << dendl;
 383
 384   bool copy_on_read = m_pending_requests.empty();
 385   bool deep_copyup = !snapc.snaps.empty() && !m_copyup_is_zero;
 386   if (m_copyup_is_zero) {
 387     m_copyup_data.clear();
 388   }
 389
 390   int r;
 391   librados::ObjectWriteOperation copyup_op;
 392   if (copy_on_read || deep_copyup) {
 393     copyup_op.exec("rbd", "copyup", m_copyup_data);
 394     ObjectRequest<I>::add_write_hint(*m_image_ctx, &copyup_op);
 395     ++m_pending_copyups;
 396   }
 397
 398   librados::ObjectWriteOperation write_op;
 399   if (!copy_on_read) {
 400     if (!deep_copyup) {
 401       write_op.exec("rbd", "copyup", m_copyup_data);
 402       ObjectRequest<I>::add_write_hint(*m_image_ctx, &write_op);
 403     }
 404
 405     // merge all pending write ops into this single RADOS op
 406     for (auto req : m_pending_requests) {
 407       ldout(cct, 20) << "add_copyup_ops " << req << dendl;
 408       req->add_copyup_ops(&write_op);
 409     }
 410
 411     if (write_op.size() > 0) {
 412       ++m_pending_copyups;
 413     }
 414   }
 415   m_lock.Unlock();
 416
 417   // issue librados ops at the end to simplify test cases
 418   std::vector<librados::snap_t> snaps;
 419   if (copyup_op.size() > 0) {
 420     // send only the copyup request with a blank snapshot context so that
 421     // all snapshots are detected from the parent for this object.  If
 422     // this is a CoW request, a second request will be created for the
 423     // actual modification.
 424     ldout(cct, 20) << "copyup with empty snapshot context" << dendl;
 425
 426     auto comp = util::create_rados_callback<
 427       CopyupRequest<I>, &CopyupRequest<I>::handle_copyup>(this);
 428     r = m_image_ctx->data_ctx.aio_operate(
 429       m_oid, comp, &copyup_op, 0, snaps,
 430       (m_trace.valid() ? m_trace.get_info() : nullptr));
 431     ceph_assert(r == 0);
 432     comp->release();
 433   }
 434
 435   if (write_op.size() > 0) {
 436     // compare-and-write doesn't add any write ops (copyup+cmpext+write
 437     // can't be executed in the same RADOS op because, unless the object
 438     // was already present in the clone, cmpext wouldn't see it)
 439     ldout(cct, 20) << (!deep_copyup && write_op.size() > 2 ?
 440                         "copyup + ops" : !deep_copyup ? "copyup" : "ops")
 441                    << " with current snapshot context" << dendl;
 442
 443     snaps.insert(snaps.end(), snapc.snaps.begin(), snapc.snaps.end());
 444     auto comp = util::create_rados_callback<
 445       CopyupRequest<I>, &CopyupRequest<I>::handle_copyup>(this);
 446     r = m_image_ctx->data_ctx.aio_operate(
 447       m_oid, comp, &write_op, snapc.seq, snaps,
 448       (m_trace.valid() ? m_trace.get_info() : nullptr));
 449     ceph_assert(r == 0);
 450     comp->release();
 451   }
 452 }
 453
 454 template <typename I>
 455 void CopyupRequest<I>::handle_copyup(int r) {
 456   auto cct = m_image_ctx->cct;
 457   unsigned pending_copyups;
 458   {
 459     Mutex::Locker locker(m_lock);
 460     ceph_assert(m_pending_copyups > 0);
 461     pending_copyups = --m_pending_copyups;
 462   }
 463
 464   ldout(cct, 20) << "oid=" << m_oid << ", " << "r=" << r << ", "
 465                  << "pending=" << pending_copyups << dendl;
 466
 467   if (r < 0 && r != -ENOENT) {
 468     lderr(cct) << "failed to copyup object: " << cpp_strerror(r) << dendl;
 469     complete_requests(false, r);
 470   }
 471
 472   if (pending_copyups == 0) {
 473     finish(0);
 474   }
 475 }
 476
 477 template <typename I>
 478 void CopyupRequest<I>::finish(int r) {
 479   auto cct = m_image_ctx->cct;
 480   ldout(cct, 20) << "oid=" << m_oid << ", r=" << r << dendl;
 481
 482   complete_requests(true, r);
 483   delete this;
 484 }
 485
 486 template <typename I>
 487 void CopyupRequest<I>::complete_requests(bool override_restart_retval, int r) {
 488   auto cct = m_image_ctx->cct;
 489   remove_from_list();
 490
 491   while (!m_pending_requests.empty()) {
 492     auto it = m_pending_requests.begin();
 493     auto req = *it;
 494     ldout(cct, 20) << "completing request " << req << dendl;
 495     req->handle_copyup(r);
 496     m_pending_requests.erase(it);
 497   }
 498
 499   if (override_restart_retval) {
 500     r = -ERESTART;
 501   }
 502
 503   while (!m_restart_requests.empty()) {
 504     auto it = m_restart_requests.begin();
 505     auto req = *it;
 506     ldout(cct, 20) << "restarting request " << req << dendl;
 507     req->handle_copyup(r);
 508     m_restart_requests.erase(it);
 509   }
 510 }
 511
 512 template <typename I>
 513 void CopyupRequest<I>::disable_append_requests() {
 514   ceph_assert(m_lock.is_locked());
 515   m_append_request_permitted = false;
 516 }
 517
 518 template <typename I>
 519 void CopyupRequest<I>::remove_from_list() {
 520   Mutex::Locker copyup_list_locker(m_image_ctx->copyup_list_lock);
 521
 522   auto it = m_image_ctx->copyup_list.find(m_object_no);
 523   if (it != m_image_ctx->copyup_list.end()) {
 524     m_image_ctx->copyup_list.erase(it);
 525   }
 526 }
 527
 528 template <typename I>
 529 bool CopyupRequest<I>::is_copyup_required() {
 530   ceph_assert(m_lock.is_locked());
 531
 532   bool copy_on_read = m_pending_requests.empty();
 533   if (copy_on_read) {
 534     // always force a copyup if CoR enabled
 535     return true;
 536   }
 537
 538   if (!m_copyup_is_zero) {
 539     return true;
 540   }
 541
 542   for (auto req : m_pending_requests) {
 543     if (!req->is_empty_write_op()) {
 544       return true;
 545     }
 546   }
 547   return false;
 548 }
 549
 550 template <typename I>
 551 bool CopyupRequest<I>::is_deep_copy() const {
 552   ceph_assert(m_image_ctx->snap_lock.is_locked());
 553   return !m_image_ctx->migration_info.empty();
 554 }
 555
 556 template <typename I>
 557 bool CopyupRequest<I>::is_update_object_map_required(int r) {
 558   ceph_assert(m_image_ctx->snap_lock.is_locked());
 559
 560   if (r < 0) {
 561     return false;
 562   }
 563
 564   if (m_image_ctx->object_map == nullptr) {
 565     return false;
 566   }
 567
 568   if (m_image_ctx->migration_info.empty()) {
 569     // migration might have completed while IO was in-flight,
 570     // assume worst-case and perform an object map update
 571     return true;
 572   }
 573
 574   auto it = m_image_ctx->migration_info.snap_map.find(CEPH_NOSNAP);
 575   ceph_assert(it != m_image_ctx->migration_info.snap_map.end());
 576   return it->second[0] != CEPH_NOSNAP;
 577 }
 578
 579 template <typename I>
 580 void CopyupRequest<I>::compute_deep_copy_snap_ids() {
 581   ceph_assert(m_image_ctx->snap_lock.is_locked());
 582
 583   // don't copy ids for the snaps updated by object deep copy or
 584   // that don't overlap
 585   std::set<uint64_t> deep_copied;
 586   for (auto &it : m_image_ctx->migration_info.snap_map) {
 587     if (it.first != CEPH_NOSNAP) {
 588       deep_copied.insert(it.second.front());
 589     }
 590   }
 591
 592   RWLock::RLocker parent_locker(m_image_ctx->parent_lock);
 593   std::copy_if(m_image_ctx->snaps.rbegin(), m_image_ctx->snaps.rend(),
 594                std::back_inserter(m_snap_ids),
 595                [this, cct=m_image_ctx->cct, &deep_copied](uint64_t snap_id) {
 596       if (deep_copied.count(snap_id)) {
 597         m_first_snap_is_clean = true;
 598         return false;
 599       }
 600
 601       uint64_t parent_overlap = 0;
 602       int r = m_image_ctx->get_parent_overlap(snap_id, &parent_overlap);
 603       if (r < 0) {
 604         ldout(cct, 5) << "failed getting parent overlap for snap_id: "
 605                       << snap_id << ": " << cpp_strerror(r) << dendl;
 606       }
 607       if (parent_overlap == 0) {
 608         return false;
 609       }
 610       std::vector<std::pair<uint64_t, uint64_t>> extents;
 611       Striper::extent_to_file(cct, &m_image_ctx->layout,
 612                               m_object_no, 0,
 613                               m_image_ctx->layout.object_size,
 614                               extents);
 615       auto overlap = m_image_ctx->prune_parent_extents(
 616           extents, parent_overlap);
 617       return overlap > 0;
 618     });
 619 }
 620
 621 } // namespace io
 622 } // namespace librbd
 623
 624 template class librbd::io::CopyupRequest<librbd::ImageCtx>;