ceph/src/mds/PurgeQueue.cc

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3 /*
   4  * Ceph - scalable distributed file system
   5  *
   6  * Copyright (C) 2015 Red Hat
   7  *
   8  * This is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License version 2.1, as published by the Free Software
  11  * Foundation.  See file COPYING.
  12  *
  13  */
  14
  15 #include "common/debug.h"
  16 #include "mds/mdstypes.h"
  17 #include "mds/CInode.h"
  18 #include "mds/MDCache.h"
  19
  20 #include "PurgeQueue.h"
  21
  22
  23 #define dout_context cct
  24 #define dout_subsys ceph_subsys_mds
  25 #undef dout_prefix
  26 #define dout_prefix _prefix(_dout, rank) << __func__ << ": "
  27 static ostream& _prefix(std::ostream *_dout, mds_rank_t rank) {
  28   return *_dout << "mds." << rank << ".purge_queue ";
  29 }
  30
  31 void PurgeItem::encode(bufferlist &bl) const
  32 {
  33   ENCODE_START(1, 1, bl);
  34   ::encode((uint8_t)action, bl);
  35   ::encode(ino, bl);
  36   ::encode(size, bl);
  37   ::encode(layout, bl, CEPH_FEATURE_FS_FILE_LAYOUT_V2);
  38   ::encode(old_pools, bl);
  39   ::encode(snapc, bl);
  40   ::encode(fragtree, bl);
  41   ENCODE_FINISH(bl);
  42 }
  43
  44 void PurgeItem::decode(bufferlist::iterator &p)
  45 {
  46   DECODE_START(1, p);
  47   ::decode((uint8_t&)action, p);
  48   ::decode(ino, p);
  49   ::decode(size, p);
  50   ::decode(layout, p);
  51   ::decode(old_pools, p);
  52   ::decode(snapc, p);
  53   ::decode(fragtree, p);
  54   DECODE_FINISH(p);
  55 }
  56
  57 // TODO: if Objecter has any slow requests, take that as a hint and
  58 // slow down our rate of purging (keep accepting pushes though)
  59 PurgeQueue::PurgeQueue(
  60       CephContext *cct_,
  61       mds_rank_t rank_,
  62       const int64_t metadata_pool_,
  63       Objecter *objecter_,
  64       Context *on_error_)
  65   :
  66     cct(cct_),
  67     rank(rank_),
  68     lock("PurgeQueue"),
  69     metadata_pool(metadata_pool_),
  70     finisher(cct, "PurgeQueue", "PQ_Finisher"),
  71     timer(cct, lock),
  72     filer(objecter_, &finisher),
  73     objecter(objecter_),
  74     journaler("pq", MDS_INO_PURGE_QUEUE + rank, metadata_pool,
  75       CEPH_FS_ONDISK_MAGIC, objecter_, nullptr, 0,
  76       &finisher),
  77     on_error(on_error_),
  78     ops_in_flight(0),
  79     max_purge_ops(0),
  80     drain_initial(0),
  81     draining(false),
  82     delayed_flush(nullptr),
  83     recovered(false)
  84 {
  85   assert(cct != nullptr);
  86   assert(on_error != nullptr);
  87   assert(objecter != nullptr);
  88   journaler.set_write_error_handler(on_error);
  89 }
  90
  91 PurgeQueue::~PurgeQueue()
  92 {
  93   if (logger) {
  94     g_ceph_context->get_perfcounters_collection()->remove(logger.get());
  95   }
  96 }
  97
  98 void PurgeQueue::create_logger()
  99 {
 100   PerfCountersBuilder pcb(g_ceph_context,
 101           "purge_queue", l_pq_first, l_pq_last);
 102   pcb.add_u64(l_pq_executing_ops, "pq_executing_ops", "Purge queue ops in flight");
 103   pcb.add_u64(l_pq_executing, "pq_executing", "Purge queue tasks in flight");
 104   pcb.add_u64_counter(l_pq_executed, "pq_executed", "Purge queue tasks executed", "purg",
 105       PerfCountersBuilder::PRIO_INTERESTING);
 106
 107   logger.reset(pcb.create_perf_counters());
 108   g_ceph_context->get_perfcounters_collection()->add(logger.get());
 109 }
 110
 111 void PurgeQueue::init()
 112 {
 113   Mutex::Locker l(lock);
 114
 115   assert(logger != nullptr);
 116
 117   finisher.start();
 118   timer.init();
 119 }
 120
 121 void PurgeQueue::activate()
 122 {
 123   Mutex::Locker l(lock);
 124   if (journaler.get_read_pos() == journaler.get_write_pos())
 125     return;
 126
 127   if (in_flight.empty()) {
 128     dout(4) << "start work (by drain)" << dendl;
 129     finisher.queue(new FunctionContext([this](int r) {
 130           Mutex::Locker l(lock);
 131           _consume();
 132           }));
 133   }
 134 }
 135
 136 void PurgeQueue::shutdown()
 137 {
 138   Mutex::Locker l(lock);
 139
 140   journaler.shutdown();
 141   timer.shutdown();
 142   finisher.stop();
 143 }
 144
 145 void PurgeQueue::open(Context *completion)
 146 {
 147   dout(4) << "opening" << dendl;
 148
 149   Mutex::Locker l(lock);
 150
 151   if (completion)
 152     waiting_for_recovery.push_back(completion);
 153
 154   journaler.recover(new FunctionContext([this](int r){
 155     if (r == -ENOENT) {
 156       dout(1) << "Purge Queue not found, assuming this is an upgrade and "
 157                  "creating it." << dendl;
 158       create(NULL);
 159     } else if (r == 0) {
 160       Mutex::Locker l(lock);
 161       dout(4) << "open complete" << dendl;
 162
 163       // Journaler only guarantees entries before head write_pos have been
 164       // fully flushed. Before appending new entries, we need to find and
 165       // drop any partial written entry.
 166       if (journaler.last_committed.write_pos < journaler.get_write_pos()) {
 167         dout(4) << "recovering write_pos" << dendl;
 168         journaler.set_read_pos(journaler.last_committed.write_pos);
 169         _recover();
 170         return;
 171       }
 172
 173       journaler.set_writeable();
 174       recovered = true;
 175       finish_contexts(g_ceph_context, waiting_for_recovery);
 176     } else {
 177       derr << "Error " << r << " loading Journaler" << dendl;
 178       on_error->complete(r);
 179     }
 180   }));
 181 }
 182
 183 void PurgeQueue::wait_for_recovery(Context* c)
 184 {
 185   Mutex::Locker l(lock);
 186   if (recovered)
 187     c->complete(0);
 188   else
 189     waiting_for_recovery.push_back(c);
 190 }
 191
 192 void PurgeQueue::_recover()
 193 {
 194   assert(lock.is_locked_by_me());
 195
 196   // Journaler::is_readable() adjusts write_pos if partial entry is encountered
 197   while (1) {
 198     if (!journaler.is_readable() &&
 199         !journaler.get_error() &&
 200         journaler.get_read_pos() < journaler.get_write_pos()) {
 201       journaler.wait_for_readable(new FunctionContext([this](int r) {
 202         Mutex::Locker l(lock);
 203         _recover();
 204       }));
 205       return;
 206     }
 207
 208     if (journaler.get_error()) {
 209       int r = journaler.get_error();
 210       derr << "Error " << r << " recovering write_pos" << dendl;
 211       on_error->complete(r);
 212       return;
 213     }
 214
 215     if (journaler.get_read_pos() == journaler.get_write_pos()) {
 216       dout(4) << "write_pos recovered" << dendl;
 217       // restore original read_pos
 218       journaler.set_read_pos(journaler.last_committed.expire_pos);
 219       journaler.set_writeable();
 220       recovered = true;
 221       finish_contexts(g_ceph_context, waiting_for_recovery);
 222       return;
 223     }
 224
 225     bufferlist bl;
 226     bool readable = journaler.try_read_entry(bl);
 227     assert(readable);  // we checked earlier
 228   }
 229 }
 230
 231 void PurgeQueue::create(Context *fin)
 232 {
 233   dout(4) << "creating" << dendl;
 234   Mutex::Locker l(lock);
 235
 236   if (fin)
 237     waiting_for_recovery.push_back(fin);
 238
 239   file_layout_t layout = file_layout_t::get_default();
 240   layout.pool_id = metadata_pool;
 241   journaler.set_writeable();
 242   journaler.create(&layout, JOURNAL_FORMAT_RESILIENT);
 243   journaler.write_head(new FunctionContext([this](int r) {
 244     Mutex::Locker l(lock);
 245     recovered = true;
 246     finish_contexts(g_ceph_context, waiting_for_recovery);
 247   }));
 248 }
 249
 250 /**
 251  * The `completion` context will always be called back via a Finisher
 252  */
 253 void PurgeQueue::push(const PurgeItem &pi, Context *completion)
 254 {
 255   dout(4) << "pushing inode 0x" << std::hex << pi.ino << std::dec << dendl;
 256   Mutex::Locker l(lock);
 257
 258   // Callers should have waited for open() before using us
 259   assert(!journaler.is_readonly());
 260
 261   bufferlist bl;
 262
 263   ::encode(pi, bl);
 264   journaler.append_entry(bl);
 265   journaler.wait_for_flush(completion);
 266
 267   // Maybe go ahead and do something with it right away
 268   bool could_consume = _consume();
 269   if (!could_consume) {
 270     // Usually, it is not necessary to explicitly flush here, because the reader
 271     // will get flushes generated inside Journaler::is_readable.  However,
 272     // if we remain in a can_consume()==false state for a long period then
 273     // we should flush in order to allow MDCache to drop its strays rather
 274     // than having them wait for purgequeue to progress.
 275     if (!delayed_flush) {
 276       delayed_flush = new FunctionContext([this](int r){
 277             delayed_flush = nullptr;
 278             journaler.flush();
 279           });
 280
 281       timer.add_event_after(
 282           g_conf->mds_purge_queue_busy_flush_period,
 283           delayed_flush);
 284     }
 285   }
 286 }
 287
 288 uint32_t PurgeQueue::_calculate_ops(const PurgeItem &item) const
 289 {
 290   uint32_t ops_required = 0;
 291   if (item.action == PurgeItem::PURGE_DIR) {
 292     // Directory, count dirfrags to be deleted
 293     std::list<frag_t> ls;
 294     if (!item.fragtree.is_leaf(frag_t())) {
 295       item.fragtree.get_leaves(ls);
 296     }
 297     // One for the root, plus any leaves
 298     ops_required = 1 + ls.size();
 299   } else {
 300     // File, work out concurrent Filer::purge deletes
 301     const uint64_t num = (item.size > 0) ?
 302       Striper::get_num_objects(item.layout, item.size) : 1;
 303
 304     ops_required = MIN(num, g_conf->filer_max_purge_ops);
 305
 306     // Account for removing (or zeroing) backtrace
 307     ops_required += 1;
 308
 309     // Account for deletions for old pools
 310     if (item.action != PurgeItem::TRUNCATE_FILE) {
 311       ops_required += item.old_pools.size();
 312     }
 313   }
 314
 315   return ops_required;
 316 }
 317
 318 bool PurgeQueue::can_consume()
 319 {
 320   dout(20) << ops_in_flight << "/" << max_purge_ops << " ops, "
 321            << in_flight.size() << "/" << g_conf->mds_max_purge_files
 322            << " files" << dendl;
 323
 324   if (in_flight.size() == 0 && cct->_conf->mds_max_purge_files > 0) {
 325     // Always permit consumption if nothing is in flight, so that the ops
 326     // limit can never be so low as to forbid all progress (unless
 327     // administrator has deliberately paused purging by setting max
 328     // purge files to zero).
 329     return true;
 330   }
 331
 332   if (ops_in_flight >= max_purge_ops) {
 333     dout(20) << "Throttling on op limit " << ops_in_flight << "/"
 334              << max_purge_ops << dendl;
 335     return false;
 336   }
 337
 338   if (in_flight.size() >= cct->_conf->mds_max_purge_files) {
 339     dout(20) << "Throttling on item limit " << in_flight.size()
 340              << "/" << cct->_conf->mds_max_purge_files << dendl;
 341     return false;
 342   } else {
 343     return true;
 344   }
 345 }
 346
 347 bool PurgeQueue::_consume()
 348 {
 349   assert(lock.is_locked_by_me());
 350
 351   bool could_consume = false;
 352   while(can_consume()) {
 353
 354     if (delayed_flush) {
 355       // We are now going to read from the journal, so any proactive
 356       // flush is no longer necessary.  This is not functionally necessary
 357       // but it can avoid generating extra fragmented flush IOs.
 358       timer.cancel_event(delayed_flush);
 359       delayed_flush = nullptr;
 360     }
 361
 362     if (!journaler.is_readable()) {
 363       dout(10) << " not readable right now" << dendl;
 364       // Because we are the writer and the reader of the journal
 365       // via the same Journaler instance, we never need to reread_head
 366       if (!journaler.have_waiter()) {
 367         journaler.wait_for_readable(new FunctionContext([this](int r) {
 368           Mutex::Locker l(lock);
 369           if (r == 0) {
 370             _consume();
 371           }
 372         }));
 373       }
 374
 375       return could_consume;
 376     }
 377
 378     could_consume = true;
 379     // The journaler is readable: consume an entry
 380     bufferlist bl;
 381     bool readable = journaler.try_read_entry(bl);
 382     assert(readable);  // we checked earlier
 383
 384     dout(20) << " decoding entry" << dendl;
 385     PurgeItem item;
 386     bufferlist::iterator q = bl.begin();
 387     try {
 388       ::decode(item, q);
 389     } catch (const buffer::error &err) {
 390       derr << "Decode error at read_pos=0x" << std::hex
 391            << journaler.get_read_pos() << dendl;
 392       on_error->complete(0);
 393     }
 394     dout(20) << " executing item (0x" << std::hex << item.ino
 395              << std::dec << ")" << dendl;
 396     _execute_item(item, journaler.get_read_pos());
 397   }
 398
 399   dout(10) << " cannot consume right now" << dendl;
 400
 401   return could_consume;
 402 }
 403
 404 void PurgeQueue::_execute_item(
 405     const PurgeItem &item,
 406     uint64_t expire_to)
 407 {
 408   assert(lock.is_locked_by_me());
 409
 410   in_flight[expire_to] = item;
 411   logger->set(l_pq_executing, in_flight.size());
 412   ops_in_flight += _calculate_ops(item);
 413   logger->set(l_pq_executing_ops, ops_in_flight);
 414
 415   SnapContext nullsnapc;
 416
 417   C_GatherBuilder gather(cct);
 418   if (item.action == PurgeItem::PURGE_FILE) {
 419     if (item.size > 0) {
 420       uint64_t num = Striper::get_num_objects(item.layout, item.size);
 421       dout(10) << " 0~" << item.size << " objects 0~" << num
 422                << " snapc " << item.snapc << " on " << item.ino << dendl;
 423       filer.purge_range(item.ino, &item.layout, item.snapc,
 424                         0, num, ceph::real_clock::now(), 0,
 425                         gather.new_sub());
 426     }
 427
 428     // remove the backtrace object if it was not purged
 429     object_t oid = CInode::get_object_name(item.ino, frag_t(), "");
 430     if (!gather.has_subs() || !item.layout.pool_ns.empty()) {
 431       object_locator_t oloc(item.layout.pool_id);
 432       dout(10) << " remove backtrace object " << oid
 433                << " pool " << oloc.pool << " snapc " << item.snapc << dendl;
 434       objecter->remove(oid, oloc, item.snapc,
 435                             ceph::real_clock::now(), 0,
 436                             gather.new_sub());
 437     }
 438
 439     // remove old backtrace objects
 440     for (const auto &p : item.old_pools) {
 441       object_locator_t oloc(p);
 442       dout(10) << " remove backtrace object " << oid
 443                << " old pool " << p << " snapc " << item.snapc << dendl;
 444       objecter->remove(oid, oloc, item.snapc,
 445                             ceph::real_clock::now(), 0,
 446                             gather.new_sub());
 447     }
 448   } else if (item.action == PurgeItem::PURGE_DIR) {
 449     object_locator_t oloc(metadata_pool);
 450     std::list<frag_t> frags;
 451     if (!item.fragtree.is_leaf(frag_t()))
 452       item.fragtree.get_leaves(frags);
 453     frags.push_back(frag_t());
 454     for (const auto &frag : frags) {
 455       object_t oid = CInode::get_object_name(item.ino, frag, "");
 456       dout(10) << " remove dirfrag " << oid << dendl;
 457       objecter->remove(oid, oloc, nullsnapc,
 458                        ceph::real_clock::now(),
 459                        0, gather.new_sub());
 460     }
 461   } else if (item.action == PurgeItem::TRUNCATE_FILE) {
 462     const uint64_t num = Striper::get_num_objects(item.layout, item.size);
 463     dout(10) << " 0~" << item.size << " objects 0~" << num
 464              << " snapc " << item.snapc << " on " << item.ino << dendl;
 465
 466     // keep backtrace object
 467     if (num > 1) {
 468       filer.purge_range(item.ino, &item.layout, item.snapc,
 469                         1, num - 1, ceph::real_clock::now(),
 470                         0, gather.new_sub());
 471     }
 472     filer.zero(item.ino, &item.layout, item.snapc,
 473                0, item.layout.object_size,
 474                ceph::real_clock::now(),
 475                0, true, gather.new_sub());
 476   } else {
 477     derr << "Invalid item (action=" << item.action << ") in purge queue, "
 478             "dropping it" << dendl;
 479     in_flight.erase(expire_to);
 480     logger->set(l_pq_executing, in_flight.size());
 481     return;
 482   }
 483   assert(gather.has_subs());
 484
 485   gather.set_finisher(new C_OnFinisher(
 486                       new FunctionContext([this, expire_to](int r){
 487     Mutex::Locker l(lock);
 488     _execute_item_complete(expire_to);
 489
 490     _consume();
 491
 492     // Have we gone idle?  If so, do an extra write_head now instead of
 493     // waiting for next flush after journaler_write_head_interval.
 494     // Also do this periodically even if not idle, so that the persisted
 495     // expire_pos doesn't fall too far behind our progress when consuming
 496     // a very long queue.
 497     if (in_flight.empty() || journaler.write_head_needed()) {
 498       journaler.write_head(new FunctionContext([this](int r){
 499             journaler.trim();
 500             }));
 501     }
 502   }), &finisher));
 503
 504   gather.activate();
 505 }
 506
 507 void PurgeQueue::_execute_item_complete(
 508     uint64_t expire_to)
 509 {
 510   assert(lock.is_locked_by_me());
 511   dout(10) << "complete at 0x" << std::hex << expire_to << std::dec << dendl;
 512   assert(in_flight.count(expire_to) == 1);
 513
 514   auto iter = in_flight.find(expire_to);
 515   assert(iter != in_flight.end());
 516   if (iter == in_flight.begin()) {
 517     // This was the lowest journal position in flight, so we can now
 518     // safely expire the journal up to here.
 519     dout(10) << "expiring to 0x" << std::hex << expire_to << std::dec << dendl;
 520     journaler.set_expire_pos(expire_to);
 521   } else {
 522     // This is completely fine, we're not supposed to purge files in
 523     // order when doing them in parallel.
 524     dout(10) << "non-sequential completion, not expiring anything" << dendl;
 525   }
 526
 527   ops_in_flight -= _calculate_ops(iter->second);
 528   logger->set(l_pq_executing_ops, ops_in_flight);
 529
 530   dout(10) << "completed item for ino 0x" << std::hex << iter->second.ino
 531            << std::dec << dendl;
 532
 533   in_flight.erase(iter);
 534   logger->set(l_pq_executing, in_flight.size());
 535   dout(10) << "in_flight.size() now " << in_flight.size() << dendl;
 536
 537   logger->inc(l_pq_executed);
 538 }
 539
 540 void PurgeQueue::update_op_limit(const MDSMap &mds_map)
 541 {
 542   Mutex::Locker l(lock);
 543
 544   uint64_t pg_count = 0;
 545   objecter->with_osdmap([&](const OSDMap& o) {
 546     // Number of PGs across all data pools
 547     const std::vector<int64_t> &data_pools = mds_map.get_data_pools();
 548     for (const auto dp : data_pools) {
 549       if (o.get_pg_pool(dp) == NULL) {
 550         // It is possible that we have an older OSDMap than MDSMap,
 551         // because we don't start watching every OSDMap until after
 552         // MDSRank is initialized
 553         dout(4) << " data pool " << dp << " not found in OSDMap" << dendl;
 554         continue;
 555       }
 556       pg_count += o.get_pg_num(dp);
 557     }
 558   });
 559
 560   // Work out a limit based on n_pgs / n_mdss, multiplied by the user's
 561   // preference for how many ops per PG
 562   max_purge_ops = uint64_t(((double)pg_count / (double)mds_map.get_max_mds()) *
 563                            cct->_conf->mds_max_purge_ops_per_pg);
 564
 565   // User may also specify a hard limit, apply this if so.
 566   if (cct->_conf->mds_max_purge_ops) {
 567     max_purge_ops = MIN(max_purge_ops, cct->_conf->mds_max_purge_ops);
 568   }
 569 }
 570
 571 void PurgeQueue::handle_conf_change(const struct md_config_t *conf,
 572                              const std::set <std::string> &changed,
 573                              const MDSMap &mds_map)
 574 {
 575   if (changed.count("mds_max_purge_ops")
 576       || changed.count("mds_max_purge_ops_per_pg")) {
 577     update_op_limit(mds_map);
 578   } else if (changed.count("mds_max_purge_files")) {
 579     Mutex::Locker l(lock);
 580
 581     if (in_flight.empty()) {
 582       // We might have gone from zero to a finite limit, so
 583       // might need to kick off consume.
 584       dout(4) << "maybe start work again (max_purge_files="
 585               << conf->mds_max_purge_files << dendl;
 586       finisher.queue(new FunctionContext([this](int r){
 587         Mutex::Locker l(lock);
 588         _consume();
 589       }));
 590     }
 591   }
 592 }
 593
 594 bool PurgeQueue::drain(
 595     uint64_t *progress,
 596     uint64_t *progress_total,
 597     size_t *in_flight_count
 598     )
 599 {
 600   assert(progress != nullptr);
 601   assert(progress_total != nullptr);
 602   assert(in_flight_count != nullptr);
 603
 604   const bool done = in_flight.empty() && (
 605       journaler.get_read_pos() == journaler.get_write_pos());
 606   if (done) {
 607     return true;
 608   }
 609
 610   const uint64_t bytes_remaining = journaler.get_write_pos()
 611                                    - journaler.get_read_pos();
 612
 613   if (!draining) {
 614     // Start of draining: remember how much there was outstanding at
 615     // this point so that we can give a progress percentage later
 616     draining = true;
 617
 618     // Life the op throttle as this daemon now has nothing to do but
 619     // drain the purge queue, so do it as fast as we can.
 620     max_purge_ops = 0xffff;
 621   }
 622
 623   drain_initial = max(bytes_remaining, drain_initial);
 624
 625   *progress = drain_initial - bytes_remaining;
 626   *progress_total = drain_initial;
 627   *in_flight_count = in_flight.size();
 628
 629   return false;
 630 }
 631