ceph/src/osd/PGLog.h

   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) 2004-2006 Sage Weil <sage@newdream.net>
   7  * Copyright (C) 2013 Cloudwatt <libre.licensing@cloudwatt.com>
   8  *
   9  * Author: Loic Dachary <loic@dachary.org>
  10  *
  11  * This is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License version 2.1, as published by the Free Software
  14  * Foundation.  See file COPYING.
  15  *
  16  */
  17 #pragma once
  18
  19 // re-include our assert to clobber boost's
  20 #include "include/ceph_assert.h"
  21 #include "osd_types.h"
  22 #include "os/ObjectStore.h"
  23 #include <list>
  24
  25 constexpr auto PGLOG_INDEXED_OBJECTS          = 1 << 0;
  26 constexpr auto PGLOG_INDEXED_CALLER_OPS       = 1 << 1;
  27 constexpr auto PGLOG_INDEXED_EXTRA_CALLER_OPS = 1 << 2;
  28 constexpr auto PGLOG_INDEXED_DUPS             = 1 << 3;
  29 constexpr auto PGLOG_INDEXED_ALL              = PGLOG_INDEXED_OBJECTS
  30                                               | PGLOG_INDEXED_CALLER_OPS
  31                                               | PGLOG_INDEXED_EXTRA_CALLER_OPS
  32                                               | PGLOG_INDEXED_DUPS;
  33
  34 class CephContext;
  35
  36 struct PGLog : DoutPrefixProvider {
  37   std::ostream& gen_prefix(std::ostream& out) const override {
  38     return out;
  39   }
  40   unsigned get_subsys() const override {
  41     return static_cast<unsigned>(ceph_subsys_osd);
  42   }
  43   CephContext *get_cct() const override {
  44     return cct;
  45   }
  46
  47   ////////////////////////////// sub classes //////////////////////////////
  48   struct LogEntryHandler {
  49     virtual void rollback(
  50       const pg_log_entry_t &entry) = 0;
  51     virtual void rollforward(
  52       const pg_log_entry_t &entry) = 0;
  53     virtual void trim(
  54       const pg_log_entry_t &entry) = 0;
  55     virtual void remove(
  56       const hobject_t &hoid) = 0;
  57     virtual void try_stash(
  58       const hobject_t &hoid,
  59       version_t v) = 0;
  60     virtual ~LogEntryHandler() {}
  61   };
  62
  63 public:
  64   /**
  65    * IndexLog - adds in-memory index of the log, by oid.
  66    * plus some methods to manipulate it all.
  67    */
  68   struct IndexedLog : public pg_log_t {
  69     mutable ceph::unordered_map<hobject_t,pg_log_entry_t*> objects;  // ptrs into log.  be careful!
  70     mutable ceph::unordered_map<osd_reqid_t,pg_log_entry_t*> caller_ops;
  71     mutable ceph::unordered_multimap<osd_reqid_t,pg_log_entry_t*> extra_caller_ops;
  72     mutable ceph::unordered_map<osd_reqid_t,pg_log_dup_t*> dup_index;
  73
  74     // recovery pointers
  75     list<pg_log_entry_t>::iterator complete_to; // not inclusive of referenced item
  76     version_t last_requested = 0;               // last object requested by primary
  77
  78     //
  79   private:
  80     mutable __u16 indexed_data = 0;
  81     /**
  82      * rollback_info_trimmed_to_riter points to the first log entry <=
  83      * rollback_info_trimmed_to
  84      *
  85      * It's a reverse_iterator because rend() is a natural representation for
  86      * tail, and rbegin() works nicely for head.
  87      */
  88     mempool::osd_pglog::list<pg_log_entry_t>::reverse_iterator
  89       rollback_info_trimmed_to_riter;
  90
  91     template <typename F>
  92     void advance_can_rollback_to(eversion_t to, F &&f) {
  93       if (to > can_rollback_to)
  94         can_rollback_to = to;
  95
  96       if (to > rollback_info_trimmed_to)
  97         rollback_info_trimmed_to = to;
  98
  99       while (rollback_info_trimmed_to_riter != log.rbegin()) {
 100         --rollback_info_trimmed_to_riter;
 101         if (rollback_info_trimmed_to_riter->version > rollback_info_trimmed_to) {
 102           ++rollback_info_trimmed_to_riter;
 103           break;
 104         }
 105         f(*rollback_info_trimmed_to_riter);
 106       }
 107     }
 108
 109     void reset_rollback_info_trimmed_to_riter() {
 110       rollback_info_trimmed_to_riter = log.rbegin();
 111       while (rollback_info_trimmed_to_riter != log.rend() &&
 112              rollback_info_trimmed_to_riter->version > rollback_info_trimmed_to)
 113         ++rollback_info_trimmed_to_riter;
 114     }
 115
 116     // indexes objects, caller ops and extra caller ops
 117   public:
 118     IndexedLog() :
 119       complete_to(log.end()),
 120       last_requested(0),
 121       indexed_data(0),
 122       rollback_info_trimmed_to_riter(log.rbegin())
 123     { }
 124
 125     template <typename... Args>
 126     explicit IndexedLog(Args&&... args) :
 127       pg_log_t(std::forward<Args>(args)...),
 128       complete_to(log.end()),
 129       last_requested(0),
 130       indexed_data(0),
 131       rollback_info_trimmed_to_riter(log.rbegin())
 132     {
 133       reset_rollback_info_trimmed_to_riter();
 134       index();
 135     }
 136
 137     IndexedLog(const IndexedLog &rhs) :
 138       pg_log_t(rhs),
 139       complete_to(log.end()),
 140       last_requested(rhs.last_requested),
 141       indexed_data(0),
 142       rollback_info_trimmed_to_riter(log.rbegin())
 143     {
 144       reset_rollback_info_trimmed_to_riter();
 145       index(rhs.indexed_data);
 146     }
 147
 148     IndexedLog &operator=(const IndexedLog &rhs) {
 149       this->~IndexedLog();
 150       new (this) IndexedLog(rhs);
 151       return *this;
 152     }
 153
 154     void trim_rollback_info_to(eversion_t to, LogEntryHandler *h) {
 155       advance_can_rollback_to(
 156         to,
 157         [&](pg_log_entry_t &entry) {
 158           h->trim(entry);
 159         });
 160     }
 161     void roll_forward_to(eversion_t to, LogEntryHandler *h) {
 162       advance_can_rollback_to(
 163         to,
 164         [&](pg_log_entry_t &entry) {
 165           h->rollforward(entry);
 166         });
 167     }
 168
 169     void skip_can_rollback_to_to_head() {
 170       advance_can_rollback_to(head, [&](const pg_log_entry_t &entry) {});
 171     }
 172
 173     mempool::osd_pglog::list<pg_log_entry_t> rewind_from_head(eversion_t newhead) {
 174       auto divergent = pg_log_t::rewind_from_head(newhead);
 175       index();
 176       reset_rollback_info_trimmed_to_riter();
 177       return divergent;
 178     }
 179
 180     template <typename T>
 181     void scan_log_after(
 182       const eversion_t &bound, ///< [in] scan entries > bound
 183       T &&f) const {
 184       auto iter = log.rbegin();
 185       while (iter != log.rend() && iter->version > bound)
 186         ++iter;
 187
 188       while (true) {
 189         if (iter == log.rbegin())
 190           break;
 191         f(*(--iter));
 192       }
 193     }
 194
 195     /****/
 196     void claim_log_and_clear_rollback_info(const pg_log_t& o) {
 197       // we must have already trimmed the old entries
 198       ceph_assert(rollback_info_trimmed_to == head);
 199       ceph_assert(rollback_info_trimmed_to_riter == log.rbegin());
 200
 201       *this = IndexedLog(o);
 202
 203       skip_can_rollback_to_to_head();
 204       index();
 205     }
 206
 207     void split_out_child(
 208       pg_t child_pgid,
 209       unsigned split_bits,
 210       IndexedLog *target);
 211
 212     void zero() {
 213       // we must have already trimmed the old entries
 214       ceph_assert(rollback_info_trimmed_to == head);
 215       ceph_assert(rollback_info_trimmed_to_riter == log.rbegin());
 216
 217       unindex();
 218       pg_log_t::clear();
 219       rollback_info_trimmed_to_riter = log.rbegin();
 220       reset_recovery_pointers();
 221     }
 222     void clear() {
 223       skip_can_rollback_to_to_head();
 224       zero();
 225     }
 226     void reset_recovery_pointers() {
 227       complete_to = log.end();
 228       last_requested = 0;
 229     }
 230
 231     bool logged_object(const hobject_t& oid) const {
 232       if (!(indexed_data & PGLOG_INDEXED_OBJECTS)) {
 233          index_objects();
 234       }
 235       return objects.count(oid);
 236     }
 237
 238     bool logged_req(const osd_reqid_t &r) const {
 239       if (!(indexed_data & PGLOG_INDEXED_CALLER_OPS)) {
 240         index_caller_ops();
 241       }
 242       if (!caller_ops.count(r)) {
 243         if (!(indexed_data & PGLOG_INDEXED_EXTRA_CALLER_OPS)) {
 244           index_extra_caller_ops();
 245         }
 246         return extra_caller_ops.count(r);
 247       }
 248       return true;
 249     }
 250
 251     bool get_request(
 252       const osd_reqid_t &r,
 253       eversion_t *version,
 254       version_t *user_version,
 255       int *return_code) const
 256     {
 257       ceph_assert(version);
 258       ceph_assert(user_version);
 259       ceph_assert(return_code);
 260       ceph::unordered_map<osd_reqid_t,pg_log_entry_t*>::const_iterator p;
 261       if (!(indexed_data & PGLOG_INDEXED_CALLER_OPS)) {
 262         index_caller_ops();
 263       }
 264       p = caller_ops.find(r);
 265       if (p != caller_ops.end()) {
 266         *version = p->second->version;
 267         *user_version = p->second->user_version;
 268         *return_code = p->second->return_code;
 269         return true;
 270       }
 271
 272       // warning: we will return *a* request for this reqid, but not
 273       // necessarily the most recent.
 274       if (!(indexed_data & PGLOG_INDEXED_EXTRA_CALLER_OPS)) {
 275         index_extra_caller_ops();
 276       }
 277       p = extra_caller_ops.find(r);
 278       if (p != extra_caller_ops.end()) {
 279         uint32_t idx = 0;
 280         for (auto i = p->second->extra_reqids.begin();
 281              i != p->second->extra_reqids.end();
 282              ++idx, ++i) {
 283           if (i->first == r) {
 284             *version = p->second->version;
 285             *user_version = i->second;
 286             *return_code = p->second->return_code;
 287             if (*return_code >= 0) {
 288               auto it = p->second->extra_reqid_return_codes.find(idx);
 289               if (it != p->second->extra_reqid_return_codes.end()) {
 290                 *return_code = it->second;
 291               }
 292             }
 293             return true;
 294           }
 295         }
 296         ceph_abort_msg("in extra_caller_ops but not extra_reqids");
 297       }
 298
 299       if (!(indexed_data & PGLOG_INDEXED_DUPS)) {
 300         index_dups();
 301       }
 302       auto q = dup_index.find(r);
 303       if (q != dup_index.end()) {
 304         *version = q->second->version;
 305         *user_version = q->second->user_version;
 306         *return_code = q->second->return_code;
 307         return true;
 308       }
 309
 310       return false;
 311     }
 312
 313     /// get a (bounded) list of recent reqids for the given object
 314     void get_object_reqids(const hobject_t& oid, unsigned max,
 315                            mempool::osd_pglog::vector<pair<osd_reqid_t, version_t> > *pls,
 316                            mempool::osd_pglog::map<uint32_t, int> *return_codes) const {
 317        // make sure object is present at least once before we do an
 318        // O(n) search.
 319       if (!(indexed_data & PGLOG_INDEXED_OBJECTS)) {
 320         index_objects();
 321       }
 322       if (objects.count(oid) == 0)
 323         return;
 324
 325       for (list<pg_log_entry_t>::const_reverse_iterator i = log.rbegin();
 326            i != log.rend();
 327            ++i) {
 328         if (i->soid == oid) {
 329           if (i->reqid_is_indexed()) {
 330             if (i->op == pg_log_entry_t::ERROR) {
 331               // propagate op errors to the cache tier's PG log
 332               return_codes->emplace(pls->size(), i->return_code);
 333             }
 334             pls->push_back(make_pair(i->reqid, i->user_version));
 335           }
 336
 337           pls->insert(pls->end(), i->extra_reqids.begin(), i->extra_reqids.end());
 338           if (pls->size() >= max) {
 339             if (pls->size() > max) {
 340               pls->resize(max);
 341             }
 342             return;
 343           }
 344         }
 345       }
 346     }
 347
 348     void index(__u16 to_index = PGLOG_INDEXED_ALL) const {
 349       // if to_index is 0, no need to run any of this code, especially
 350       // loop below; this can happen with copy constructor for
 351       // IndexedLog (and indirectly through assignment operator)
 352       if (!to_index) return;
 353
 354       if (to_index & PGLOG_INDEXED_OBJECTS)
 355         objects.clear();
 356       if (to_index & PGLOG_INDEXED_CALLER_OPS)
 357         caller_ops.clear();
 358       if (to_index & PGLOG_INDEXED_EXTRA_CALLER_OPS)
 359         extra_caller_ops.clear();
 360       if (to_index & PGLOG_INDEXED_DUPS) {
 361         dup_index.clear();
 362         for (auto& i : dups) {
 363           dup_index[i.reqid] = const_cast<pg_log_dup_t*>(&i);
 364         }
 365       }
 366
 367       constexpr __u16 any_log_entry_index =
 368         PGLOG_INDEXED_OBJECTS |
 369         PGLOG_INDEXED_CALLER_OPS |
 370         PGLOG_INDEXED_EXTRA_CALLER_OPS;
 371
 372       if (to_index & any_log_entry_index) {
 373         for (list<pg_log_entry_t>::const_iterator i = log.begin();
 374              i != log.end();
 375              ++i) {
 376           if (to_index & PGLOG_INDEXED_OBJECTS) {
 377             if (i->object_is_indexed()) {
 378               objects[i->soid] = const_cast<pg_log_entry_t*>(&(*i));
 379             }
 380           }
 381
 382           if (to_index & PGLOG_INDEXED_CALLER_OPS) {
 383             if (i->reqid_is_indexed()) {
 384               caller_ops[i->reqid] = const_cast<pg_log_entry_t*>(&(*i));
 385             }
 386           }
 387
 388           if (to_index & PGLOG_INDEXED_EXTRA_CALLER_OPS) {
 389             for (auto j = i->extra_reqids.begin();
 390                  j != i->extra_reqids.end();
 391                  ++j) {
 392               extra_caller_ops.insert(
 393                 make_pair(j->first, const_cast<pg_log_entry_t*>(&(*i))));
 394             }
 395           }
 396         }
 397       }
 398
 399       indexed_data |= to_index;
 400     }
 401
 402     void index_objects() const {
 403       index(PGLOG_INDEXED_OBJECTS);
 404     }
 405
 406     void index_caller_ops() const {
 407       index(PGLOG_INDEXED_CALLER_OPS);
 408     }
 409
 410     void index_extra_caller_ops() const {
 411       index(PGLOG_INDEXED_EXTRA_CALLER_OPS);
 412     }
 413
 414     void index_dups() const {
 415       index(PGLOG_INDEXED_DUPS);
 416     }
 417
 418     void index(pg_log_entry_t& e) {
 419       if ((indexed_data & PGLOG_INDEXED_OBJECTS) && e.object_is_indexed()) {
 420         if (objects.count(e.soid) == 0 ||
 421             objects[e.soid]->version < e.version)
 422           objects[e.soid] = &e;
 423       }
 424       if (indexed_data & PGLOG_INDEXED_CALLER_OPS) {
 425         // divergent merge_log indexes new before unindexing old
 426         if (e.reqid_is_indexed()) {
 427           caller_ops[e.reqid] = &e;
 428         }
 429       }
 430       if (indexed_data & PGLOG_INDEXED_EXTRA_CALLER_OPS) {
 431         for (auto j = e.extra_reqids.begin();
 432              j != e.extra_reqids.end();
 433              ++j) {
 434           extra_caller_ops.insert(make_pair(j->first, &e));
 435         }
 436       }
 437     }
 438
 439     void unindex() {
 440       objects.clear();
 441       caller_ops.clear();
 442       extra_caller_ops.clear();
 443       dup_index.clear();
 444       indexed_data = 0;
 445     }
 446
 447     void unindex(const pg_log_entry_t& e) {
 448       // NOTE: this only works if we remove from the _tail_ of the log!
 449       if (indexed_data & PGLOG_INDEXED_OBJECTS) {
 450         auto it = objects.find(e.soid);
 451         if (it != objects.end() && it->second->version == e.version)
 452           objects.erase(it);
 453       }
 454       if (e.reqid_is_indexed()) {
 455         if (indexed_data & PGLOG_INDEXED_CALLER_OPS) {
 456           auto it = caller_ops.find(e.reqid);
 457           // divergent merge_log indexes new before unindexing old
 458           if (it != caller_ops.end() && it->second == &e)
 459             caller_ops.erase(it);
 460         }
 461       }
 462       if (indexed_data & PGLOG_INDEXED_EXTRA_CALLER_OPS) {
 463         for (auto j = e.extra_reqids.begin();
 464              j != e.extra_reqids.end();
 465              ++j) {
 466           for (ceph::unordered_multimap<osd_reqid_t,pg_log_entry_t*>::iterator k =
 467                  extra_caller_ops.find(j->first);
 468                k != extra_caller_ops.end() && k->first == j->first;
 469                ++k) {
 470             if (k->second == &e) {
 471               extra_caller_ops.erase(k);
 472               break;
 473             }
 474           }
 475         }
 476       }
 477     }
 478
 479     void index(pg_log_dup_t& e) {
 480       if (indexed_data & PGLOG_INDEXED_DUPS) {
 481         dup_index[e.reqid] = &e;
 482       }
 483     }
 484
 485     void unindex(const pg_log_dup_t& e) {
 486       if (indexed_data & PGLOG_INDEXED_DUPS) {
 487         auto i = dup_index.find(e.reqid);
 488         if (i != dup_index.end()) {
 489           dup_index.erase(i);
 490         }
 491       }
 492     }
 493
 494     // actors
 495     void add(const pg_log_entry_t& e, bool applied = true) {
 496       if (!applied) {
 497         ceph_assert(get_can_rollback_to() == head);
 498       }
 499
 500       // make sure our buffers don't pin bigger buffers
 501       e.mod_desc.trim_bl();
 502
 503       // add to log
 504       log.push_back(e);
 505
 506       // riter previously pointed to the previous entry
 507       if (rollback_info_trimmed_to_riter == log.rbegin())
 508         ++rollback_info_trimmed_to_riter;
 509
 510       ceph_assert(e.version > head);
 511       ceph_assert(head.version == 0 || e.version.version > head.version);
 512       head = e.version;
 513
 514       // to our index
 515       if ((indexed_data & PGLOG_INDEXED_OBJECTS) && e.object_is_indexed()) {
 516         objects[e.soid] = &(log.back());
 517       }
 518       if (indexed_data & PGLOG_INDEXED_CALLER_OPS) {
 519         if (e.reqid_is_indexed()) {
 520           caller_ops[e.reqid] = &(log.back());
 521         }
 522       }
 523
 524       if (indexed_data & PGLOG_INDEXED_EXTRA_CALLER_OPS) {
 525         for (auto j = e.extra_reqids.begin();
 526              j != e.extra_reqids.end();
 527              ++j) {
 528           extra_caller_ops.insert(make_pair(j->first, &(log.back())));
 529         }
 530       }
 531
 532       if (!applied) {
 533         skip_can_rollback_to_to_head();
 534       }
 535     } // add
 536
 537     void trim(
 538       CephContext* cct,
 539       eversion_t s,
 540       set<eversion_t> *trimmed,
 541       set<string>* trimmed_dups,
 542       eversion_t *write_from_dups);
 543
 544     ostream& print(ostream& out) const;
 545   }; // IndexedLog
 546
 547
 548 protected:
 549   //////////////////// data members ////////////////////
 550
 551   pg_missing_tracker_t missing;
 552   IndexedLog  log;
 553
 554   eversion_t dirty_to;         ///< must clear/writeout all keys <= dirty_to
 555   eversion_t dirty_from;       ///< must clear/writeout all keys >= dirty_from
 556   eversion_t writeout_from;    ///< must writout keys >= writeout_from
 557   set<eversion_t> trimmed;     ///< must clear keys in trimmed
 558   eversion_t dirty_to_dups;    ///< must clear/writeout all dups <= dirty_to_dups
 559   eversion_t dirty_from_dups;  ///< must clear/writeout all dups >= dirty_from_dups
 560   eversion_t write_from_dups;  ///< must write keys >= write_from_dups
 561   set<string> trimmed_dups;    ///< must clear keys in trimmed_dups
 562   CephContext *cct;
 563   bool pg_log_debug;
 564   /// Log is clean on [dirty_to, dirty_from)
 565   bool touched_log;
 566   bool clear_divergent_priors;
 567   bool rebuilt_missing_with_deletes = false;
 568
 569   void mark_dirty_to(eversion_t to) {
 570     if (to > dirty_to)
 571       dirty_to = to;
 572   }
 573   void mark_dirty_from(eversion_t from) {
 574     if (from < dirty_from)
 575       dirty_from = from;
 576   }
 577   void mark_writeout_from(eversion_t from) {
 578     if (from < writeout_from)
 579       writeout_from = from;
 580   }
 581   void mark_dirty_to_dups(eversion_t to) {
 582     if (to > dirty_to_dups)
 583       dirty_to_dups = to;
 584   }
 585   void mark_dirty_from_dups(eversion_t from) {
 586     if (from < dirty_from_dups)
 587       dirty_from_dups = from;
 588   }
 589 public:
 590   bool is_dirty() const {
 591     return !touched_log ||
 592       (dirty_to != eversion_t()) ||
 593       (dirty_from != eversion_t::max()) ||
 594       (writeout_from != eversion_t::max()) ||
 595       !(trimmed.empty()) ||
 596       !missing.is_clean() ||
 597       !(trimmed_dups.empty()) ||
 598       (dirty_to_dups != eversion_t()) ||
 599       (dirty_from_dups != eversion_t::max()) ||
 600       (write_from_dups != eversion_t::max()) ||
 601       rebuilt_missing_with_deletes;
 602   }
 603   void mark_log_for_rewrite() {
 604     mark_dirty_to(eversion_t::max());
 605     mark_dirty_from(eversion_t());
 606     mark_dirty_to_dups(eversion_t::max());
 607     mark_dirty_from_dups(eversion_t());
 608     touched_log = false;
 609   }
 610   bool get_rebuilt_missing_with_deletes() const {
 611     return rebuilt_missing_with_deletes;
 612   }
 613 protected:
 614
 615   /// DEBUG
 616   set<string> log_keys_debug;
 617   static void clear_after(set<string> *log_keys_debug, const string &lb) {
 618     if (!log_keys_debug)
 619       return;
 620     for (set<string>::iterator i = log_keys_debug->lower_bound(lb);
 621          i != log_keys_debug->end();
 622          log_keys_debug->erase(i++));
 623   }
 624   static void clear_up_to(set<string> *log_keys_debug, const string &ub) {
 625     if (!log_keys_debug)
 626       return;
 627     for (set<string>::iterator i = log_keys_debug->begin();
 628          i != log_keys_debug->end() && *i < ub;
 629          log_keys_debug->erase(i++));
 630   }
 631
 632   void check();
 633   void undirty() {
 634     dirty_to = eversion_t();
 635     dirty_from = eversion_t::max();
 636     touched_log = true;
 637     trimmed.clear();
 638     trimmed_dups.clear();
 639     writeout_from = eversion_t::max();
 640     check();
 641     missing.flush();
 642     dirty_to_dups = eversion_t();
 643     dirty_from_dups = eversion_t::max();
 644     write_from_dups = eversion_t::max();
 645   }
 646 public:
 647
 648   // cppcheck-suppress noExplicitConstructor
 649   PGLog(CephContext *cct) :
 650     dirty_from(eversion_t::max()),
 651     writeout_from(eversion_t::max()),
 652     dirty_from_dups(eversion_t::max()),
 653     write_from_dups(eversion_t::max()),
 654     cct(cct),
 655     pg_log_debug(!(cct && !(cct->_conf->osd_debug_pg_log_writeout))),
 656     touched_log(false),
 657     clear_divergent_priors(false)
 658   { }
 659
 660   void reset_backfill();
 661
 662   void clear();
 663
 664   //////////////////// get or set missing ////////////////////
 665
 666   const pg_missing_tracker_t& get_missing() const { return missing; }
 667
 668   void missing_add(const hobject_t& oid, eversion_t need, eversion_t have, bool is_delete=false) {
 669     missing.add(oid, need, have, is_delete);
 670   }
 671
 672   void missing_add_next_entry(const pg_log_entry_t& e) {
 673     missing.add_next_event(e);
 674   }
 675
 676   //////////////////// get or set log ////////////////////
 677
 678   const IndexedLog &get_log() const { return log; }
 679
 680   const eversion_t &get_tail() const { return log.tail; }
 681
 682   void set_tail(eversion_t tail) { log.tail = tail; }
 683
 684   const eversion_t &get_head() const { return log.head; }
 685
 686   void set_head(eversion_t head) { log.head = head; }
 687
 688   void set_last_requested(version_t last_requested) {
 689     log.last_requested = last_requested;
 690   }
 691
 692   void index() { log.index(); }
 693
 694   void unindex() { log.unindex(); }
 695
 696   void add(const pg_log_entry_t& e, bool applied = true) {
 697     mark_writeout_from(e.version);
 698     log.add(e, applied);
 699   }
 700
 701   void reset_recovery_pointers() { log.reset_recovery_pointers(); }
 702
 703   static void clear_info_log(
 704     spg_t pgid,
 705     ObjectStore::Transaction *t);
 706
 707   void trim(
 708     eversion_t trim_to,
 709     pg_info_t &info,
 710     bool transaction_applied = true,
 711     bool async = false);
 712
 713   void roll_forward_to(
 714     eversion_t roll_forward_to,
 715     LogEntryHandler *h) {
 716     log.roll_forward_to(
 717       roll_forward_to,
 718       h);
 719   }
 720
 721   eversion_t get_can_rollback_to() const {
 722     return log.get_can_rollback_to();
 723   }
 724
 725   void roll_forward(LogEntryHandler *h) {
 726     roll_forward_to(
 727       log.head,
 728       h);
 729   }
 730
 731   //////////////////// get or set log & missing ////////////////////
 732
 733   void reset_backfill_claim_log(const pg_log_t &o, LogEntryHandler *h) {
 734     log.trim_rollback_info_to(log.head, h);
 735     log.claim_log_and_clear_rollback_info(o);
 736     missing.clear();
 737     mark_dirty_to(eversion_t::max());
 738     mark_dirty_to_dups(eversion_t::max());
 739   }
 740
 741   void split_into(
 742       pg_t child_pgid,
 743       unsigned split_bits,
 744       PGLog *opg_log) {
 745     log.split_out_child(child_pgid, split_bits, &opg_log->log);
 746     missing.split_into(child_pgid, split_bits, &(opg_log->missing));
 747     opg_log->mark_dirty_to(eversion_t::max());
 748     opg_log->mark_dirty_to_dups(eversion_t::max());
 749     mark_dirty_to(eversion_t::max());
 750     mark_dirty_to_dups(eversion_t::max());
 751     if (missing.may_include_deletes)
 752       opg_log->rebuilt_missing_with_deletes = true;
 753   }
 754
 755   void merge_from(
 756     const vector<PGLog*>& sources,
 757     eversion_t last_update) {
 758     unindex();
 759     missing.clear();
 760
 761     vector<pg_log_t*> slogs;
 762     for (auto s : sources) {
 763       slogs.push_back(&s->log);
 764     }
 765     log.merge_from(slogs, last_update);
 766
 767     index();
 768
 769     mark_log_for_rewrite();
 770   }
 771
 772   void recover_got(hobject_t oid, eversion_t v, pg_info_t &info) {
 773     if (missing.is_missing(oid, v)) {
 774       missing.got(oid, v);
 775       info.stats.stats.sum.num_objects_missing = missing.num_missing();
 776
 777       // raise last_complete?
 778       if (missing.get_items().empty()) {
 779         log.complete_to = log.log.end();
 780         info.last_complete = info.last_update;
 781       }
 782       auto oldest_need = missing.get_oldest_need();
 783       while (log.complete_to != log.log.end()) {
 784         if (oldest_need <= log.complete_to->version)
 785           break;
 786         if (info.last_complete < log.complete_to->version)
 787           info.last_complete = log.complete_to->version;
 788         ++log.complete_to;
 789       }
 790     }
 791
 792     ceph_assert(log.get_can_rollback_to() >= v);
 793   }
 794
 795   void reset_complete_to(pg_info_t *info) {
 796     log.complete_to = log.log.begin();
 797     ceph_assert(log.complete_to != log.log.end());
 798     auto oldest_need = missing.get_oldest_need();
 799     if (oldest_need != eversion_t()) {
 800       while (log.complete_to->version < oldest_need) {
 801         ++log.complete_to;
 802         ceph_assert(log.complete_to != log.log.end());
 803       }
 804     }
 805     if (!info)
 806       return;
 807     if (log.complete_to == log.log.begin()) {
 808       info->last_complete = eversion_t();
 809     } else {
 810       --log.complete_to;
 811       info->last_complete = log.complete_to->version;
 812       ++log.complete_to;
 813     }
 814   }
 815
 816   void activate_not_complete(pg_info_t &info) {
 817     reset_complete_to(&info);
 818     log.last_requested = 0;
 819   }
 820
 821   void proc_replica_log(pg_info_t &oinfo,
 822                         const pg_log_t &olog,
 823                         pg_missing_t& omissing, pg_shard_t from) const;
 824
 825   void rebuild_missing_set_with_deletes(ObjectStore *store,
 826                                         ObjectStore::CollectionHandle& ch,
 827                                         const pg_info_t &info);
 828
 829 protected:
 830   static void split_by_object(
 831     mempool::osd_pglog::list<pg_log_entry_t> &entries,
 832     map<hobject_t, mempool::osd_pglog::list<pg_log_entry_t>> *out_entries) {
 833     while (!entries.empty()) {
 834       auto &out_list = (*out_entries)[entries.front().soid];
 835       out_list.splice(out_list.end(), entries, entries.begin());
 836     }
 837   }
 838
 839   /**
 840    * _merge_object_divergent_entries
 841    *
 842    * There are 5 distinct cases:
 843    * 1) There is a more recent update: in this case we assume we adjusted the
 844    *    store and missing during merge_log
 845    * 2) The first entry in the divergent sequence is a create.  This might
 846    *    either be because the object is a clone or because prior_version is
 847    *    eversion_t().  In this case the object does not exist and we must
 848    *    adjust missing and the store to match.
 849    * 3) We are currently missing the object.  In this case, we adjust the
 850    *    missing to our prior_version taking care to add a divergent_prior
 851    *    if necessary
 852    * 4) We can rollback all of the entries.  In this case, we do so using
 853    *    the rollbacker and return -- the object does not go into missing.
 854    * 5) We cannot rollback at least 1 of the entries.  In this case, we
 855    *    clear the object out of the store and add a missing entry at
 856    *    prior_version taking care to add a divergent_prior if
 857    *    necessary.
 858    */
 859   template <typename missing_type>
 860   static void _merge_object_divergent_entries(
 861     const IndexedLog &log,               ///< [in] log to merge against
 862     const hobject_t &hoid,               ///< [in] object we are merging
 863     const mempool::osd_pglog::list<pg_log_entry_t> &orig_entries, ///< [in] entries for hoid to merge
 864     const pg_info_t &info,              ///< [in] info for merging entries
 865     eversion_t olog_can_rollback_to,     ///< [in] rollback boundary
 866     missing_type &missing,               ///< [in,out] missing to adjust, use
 867     LogEntryHandler *rollbacker,         ///< [in] optional rollbacker object
 868     const DoutPrefixProvider *dpp        ///< [in] logging provider
 869     ) {
 870     ldpp_dout(dpp, 20) << __func__ << ": merging hoid " << hoid
 871                        << " entries: " << orig_entries << dendl;
 872
 873     if (hoid > info.last_backfill) {
 874       ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid << " after last_backfill"
 875                          << dendl;
 876       return;
 877     }
 878
 879     // entries is non-empty
 880     ceph_assert(!orig_entries.empty());
 881     // strip out and ignore ERROR entries
 882     mempool::osd_pglog::list<pg_log_entry_t> entries;
 883     eversion_t last;
 884     bool seen_non_error = false;
 885     for (list<pg_log_entry_t>::const_iterator i = orig_entries.begin();
 886          i != orig_entries.end();
 887          ++i) {
 888       // all entries are on hoid
 889       ceph_assert(i->soid == hoid);
 890       // did not see error entries before this entry and this entry is not error
 891       // then this entry is the first non error entry
 892       bool first_non_error = ! seen_non_error && ! i->is_error();
 893       if (! i->is_error() ) {
 894         // see a non error entry now
 895         seen_non_error = true;
 896       }
 897
 898       // No need to check the first entry since it prior_version is unavailable
 899       // in the list
 900       // No need to check if the prior_version is the minimal version
 901       // No need to check the first non-error entry since the leading error
 902       // entries are not its prior version
 903       if (i != orig_entries.begin() && i->prior_version != eversion_t() &&
 904           ! first_non_error) {
 905         // in increasing order of version
 906         ceph_assert(i->version > last);
 907         // prior_version correct (unless it is an ERROR entry)
 908         ceph_assert(i->prior_version == last || i->is_error());
 909       }
 910       if (i->is_error()) {
 911         ldpp_dout(dpp, 20) << __func__ << ": ignoring " << *i << dendl;
 912       } else {
 913         ldpp_dout(dpp, 20) << __func__ << ": keeping " << *i << dendl;
 914         entries.push_back(*i);
 915         last = i->version;
 916       }
 917     }
 918     if (entries.empty()) {
 919       ldpp_dout(dpp, 10) << __func__ << ": no non-ERROR entries" << dendl;
 920       return;
 921     }
 922
 923     const eversion_t prior_version = entries.begin()->prior_version;
 924     const eversion_t first_divergent_update = entries.begin()->version;
 925     const eversion_t last_divergent_update = entries.rbegin()->version;
 926     const bool object_not_in_store =
 927       !missing.is_missing(hoid) &&
 928       entries.rbegin()->is_delete();
 929     ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid
 930                        << " prior_version: " << prior_version
 931                        << " first_divergent_update: " << first_divergent_update
 932                        << " last_divergent_update: " << last_divergent_update
 933                        << dendl;
 934
 935     ceph::unordered_map<hobject_t, pg_log_entry_t*>::const_iterator objiter =
 936       log.objects.find(hoid);
 937     if (objiter != log.objects.end() &&
 938         objiter->second->version >= first_divergent_update) {
 939       /// Case 1)
 940       ldpp_dout(dpp, 10) << __func__ << ": more recent entry found: "
 941                          << *objiter->second << ", already merged" << dendl;
 942
 943       ceph_assert(objiter->second->version > last_divergent_update);
 944
 945       // ensure missing has been updated appropriately
 946       if (objiter->second->is_update() ||
 947           (missing.may_include_deletes && objiter->second->is_delete())) {
 948         ceph_assert(missing.is_missing(hoid) &&
 949                missing.get_items().at(hoid).need == objiter->second->version);
 950       } else {
 951         ceph_assert(!missing.is_missing(hoid));
 952       }
 953       missing.revise_have(hoid, eversion_t());
 954       if (rollbacker) {
 955         if (!object_not_in_store) {
 956           rollbacker->remove(hoid);
 957         }
 958         for (auto &&i: entries) {
 959           rollbacker->trim(i);
 960         }
 961       }
 962       return;
 963     }
 964
 965     ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid
 966                        <<" has no more recent entries in log" << dendl;
 967     if (prior_version == eversion_t() || entries.front().is_clone()) {
 968       /// Case 2)
 969       ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid
 970                          << " prior_version or op type indicates creation,"
 971                          << " deleting"
 972                          << dendl;
 973       if (missing.is_missing(hoid))
 974         missing.rm(missing.get_items().find(hoid));
 975       if (rollbacker) {
 976         if (!object_not_in_store) {
 977           rollbacker->remove(hoid);
 978         }
 979         for (auto &&i: entries) {
 980           rollbacker->trim(i);
 981         }
 982       }
 983       return;
 984     }
 985
 986     if (missing.is_missing(hoid)) {
 987       /// Case 3)
 988       ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid
 989                          << " missing, " << missing.get_items().at(hoid)
 990                          << " adjusting" << dendl;
 991
 992       if (missing.get_items().at(hoid).have == prior_version) {
 993         ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid
 994                            << " missing.have is prior_version " << prior_version
 995                            << " removing from missing" << dendl;
 996         missing.rm(missing.get_items().find(hoid));
 997       } else {
 998         ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid
 999                            << " missing.have is " << missing.get_items().at(hoid).have
1000                            << ", adjusting" << dendl;
1001         missing.revise_need(hoid, prior_version, false);
1002         if (prior_version <= info.log_tail) {
1003           ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid
1004                              << " prior_version " << prior_version
1005                              << " <= info.log_tail "
1006                              << info.log_tail << dendl;
1007         }
1008       }
1009       if (rollbacker) {
1010         for (auto &&i: entries) {
1011           rollbacker->trim(i);
1012         }
1013       }
1014       return;
1015     }
1016
1017     ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid
1018                        << " must be rolled back or recovered,"
1019                        << " attempting to rollback"
1020                        << dendl;
1021     bool can_rollback = true;
1022     // We are going to make an important decision based on the
1023     // olog_can_rollback_to value we have received, better known it.
1024     ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid
1025                        << " olog_can_rollback_to: "
1026                        << olog_can_rollback_to << dendl;
1027     /// Distinguish between 4) and 5)
1028     for (list<pg_log_entry_t>::const_reverse_iterator i = entries.rbegin();
1029          i != entries.rend();
1030          ++i) {
1031       if (!i->can_rollback() || i->version <= olog_can_rollback_to) {
1032         ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid << " cannot rollback "
1033                            << *i << dendl;
1034         can_rollback = false;
1035         break;
1036       }
1037     }
1038
1039     if (can_rollback) {
1040       /// Case 4)
1041       for (list<pg_log_entry_t>::const_reverse_iterator i = entries.rbegin();
1042            i != entries.rend();
1043            ++i) {
1044         ceph_assert(i->can_rollback() && i->version > olog_can_rollback_to);
1045         ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid
1046                            << " rolling back " << *i << dendl;
1047         if (rollbacker)
1048           rollbacker->rollback(*i);
1049       }
1050       ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid
1051                          << " rolled back" << dendl;
1052       return;
1053     } else {
1054       /// Case 5)
1055       ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid << " cannot roll back, "
1056                          << "removing and adding to missing" << dendl;
1057       if (rollbacker) {
1058         if (!object_not_in_store)
1059           rollbacker->remove(hoid);
1060         for (auto &&i: entries) {
1061           rollbacker->trim(i);
1062         }
1063       }
1064       missing.add(hoid, prior_version, eversion_t(), false);
1065       if (prior_version <= info.log_tail) {
1066         ldpp_dout(dpp, 10) << __func__ << ": hoid " << hoid
1067                            << " prior_version " << prior_version
1068                            << " <= info.log_tail "
1069                            << info.log_tail << dendl;
1070       }
1071     }
1072   }
1073
1074   /// Merge all entries using above
1075   template <typename missing_type>
1076   static void _merge_divergent_entries(
1077     const IndexedLog &log,               ///< [in] log to merge against
1078     mempool::osd_pglog::list<pg_log_entry_t> &entries,       ///< [in] entries to merge
1079     const pg_info_t &oinfo,              ///< [in] info for merging entries
1080     eversion_t olog_can_rollback_to,     ///< [in] rollback boundary
1081     missing_type &omissing,              ///< [in,out] missing to adjust, use
1082     LogEntryHandler *rollbacker,         ///< [in] optional rollbacker object
1083     const DoutPrefixProvider *dpp        ///< [in] logging provider
1084     ) {
1085     map<hobject_t, mempool::osd_pglog::list<pg_log_entry_t> > split;
1086     split_by_object(entries, &split);
1087     for (map<hobject_t, mempool::osd_pglog::list<pg_log_entry_t>>::iterator i = split.begin();
1088          i != split.end();
1089          ++i) {
1090       _merge_object_divergent_entries(
1091         log,
1092         i->first,
1093         i->second,
1094         oinfo,
1095         olog_can_rollback_to,
1096         omissing,
1097         rollbacker,
1098         dpp);
1099     }
1100   }
1101
1102   /**
1103    * Exists for use in TestPGLog for simply testing single divergent log
1104    * cases
1105    */
1106   void merge_old_entry(
1107     ObjectStore::Transaction& t,
1108     const pg_log_entry_t& oe,
1109     const pg_info_t& info,
1110     LogEntryHandler *rollbacker) {
1111     mempool::osd_pglog::list<pg_log_entry_t> entries;
1112     entries.push_back(oe);
1113     _merge_object_divergent_entries(
1114       log,
1115       oe.soid,
1116       entries,
1117       info,
1118       log.get_can_rollback_to(),
1119       missing,
1120       rollbacker,
1121       this);
1122   }
1123
1124   bool merge_log_dups(const pg_log_t& olog);
1125
1126 public:
1127
1128   void rewind_divergent_log(eversion_t newhead,
1129                             pg_info_t &info,
1130                             LogEntryHandler *rollbacker,
1131                             bool &dirty_info,
1132                             bool &dirty_big_info);
1133
1134   void merge_log(pg_info_t &oinfo,
1135                  pg_log_t &olog,
1136                  pg_shard_t from,
1137                  pg_info_t &info, LogEntryHandler *rollbacker,
1138                  bool &dirty_info, bool &dirty_big_info);
1139
1140   template <typename missing_type>
1141   static bool append_log_entries_update_missing(
1142     const hobject_t &last_backfill,
1143     bool last_backfill_bitwise,
1144     const mempool::osd_pglog::list<pg_log_entry_t> &entries,
1145     bool maintain_rollback,
1146     IndexedLog *log,
1147     missing_type &missing,
1148     LogEntryHandler *rollbacker,
1149     const DoutPrefixProvider *dpp) {
1150     bool invalidate_stats = false;
1151     if (log && !entries.empty()) {
1152       ceph_assert(log->head < entries.begin()->version);
1153     }
1154     for (list<pg_log_entry_t>::const_iterator p = entries.begin();
1155          p != entries.end();
1156          ++p) {
1157       invalidate_stats = invalidate_stats || !p->is_error();
1158       if (log) {
1159         ldpp_dout(dpp, 20) << "update missing, append " << *p << dendl;
1160         log->add(*p);
1161       }
1162       if (p->soid <= last_backfill &&
1163           !p->is_error()) {
1164         if (missing.may_include_deletes) {
1165           missing.add_next_event(*p);
1166         } else {
1167           if (p->is_delete()) {
1168             missing.rm(p->soid, p->version);
1169           } else {
1170             missing.add_next_event(*p);
1171           }
1172           if (rollbacker) {
1173             // hack to match PG::mark_all_unfound_lost
1174             if (maintain_rollback && p->is_lost_delete() && p->can_rollback()) {
1175               rollbacker->try_stash(p->soid, p->version.version);
1176             } else if (p->is_delete()) {
1177               rollbacker->remove(p->soid);
1178             }
1179           }
1180         }
1181       }
1182     }
1183     return invalidate_stats;
1184   }
1185   bool append_new_log_entries(
1186     const hobject_t &last_backfill,
1187     bool last_backfill_bitwise,
1188     const mempool::osd_pglog::list<pg_log_entry_t> &entries,
1189     LogEntryHandler *rollbacker) {
1190     bool invalidate_stats = append_log_entries_update_missing(
1191       last_backfill,
1192       last_backfill_bitwise,
1193       entries,
1194       true,
1195       &log,
1196       missing,
1197       rollbacker,
1198       this);
1199     if (!entries.empty()) {
1200       mark_writeout_from(entries.begin()->version);
1201       if (entries.begin()->is_lost_delete()) {
1202         // hack: since lost deletes queue recovery directly, and don't
1203         // go through activate_not_complete() again, our complete_to
1204         // iterator may still point at log.end(). Reset it to point
1205         // before these new lost_delete entries.  This only occurs
1206         // when lost+delete entries are initially added, which is
1207         // always in a list of solely lost_delete entries, so it is
1208         // sufficient to check whether the first entry is a
1209         // lost_delete
1210         reset_complete_to(nullptr);
1211       }
1212     }
1213     return invalidate_stats;
1214   }
1215
1216   void write_log_and_missing(
1217     ObjectStore::Transaction& t,
1218     map<string,bufferlist> *km,
1219     const coll_t& coll,
1220     const ghobject_t &log_oid,
1221     bool require_rollback);
1222
1223   static void write_log_and_missing_wo_missing(
1224     ObjectStore::Transaction& t,
1225     map<string,bufferlist>* km,
1226     pg_log_t &log,
1227     const coll_t& coll,
1228     const ghobject_t &log_oid, map<eversion_t, hobject_t> &divergent_priors,
1229     bool require_rollback);
1230
1231   static void write_log_and_missing(
1232     ObjectStore::Transaction& t,
1233     map<string,bufferlist>* km,
1234     pg_log_t &log,
1235     const coll_t& coll,
1236     const ghobject_t &log_oid,
1237     const pg_missing_tracker_t &missing,
1238     bool require_rollback,
1239     bool *rebuilt_missing_set_with_deletes);
1240
1241   static void _write_log_and_missing_wo_missing(
1242     ObjectStore::Transaction& t,
1243     map<string,bufferlist>* km,
1244     pg_log_t &log,
1245     const coll_t& coll, const ghobject_t &log_oid,
1246     map<eversion_t, hobject_t> &divergent_priors,
1247     eversion_t dirty_to,
1248     eversion_t dirty_from,
1249     eversion_t writeout_from,
1250     bool dirty_divergent_priors,
1251     bool touch_log,
1252     bool require_rollback,
1253     eversion_t dirty_to_dups,
1254     eversion_t dirty_from_dups,
1255     eversion_t write_from_dups,
1256     set<string> *log_keys_debug
1257     );
1258
1259   static void _write_log_and_missing(
1260     ObjectStore::Transaction& t,
1261     map<string,bufferlist>* km,
1262     pg_log_t &log,
1263     const coll_t& coll, const ghobject_t &log_oid,
1264     eversion_t dirty_to,
1265     eversion_t dirty_from,
1266     eversion_t writeout_from,
1267     set<eversion_t> &&trimmed,
1268     set<string> &&trimmed_dups,
1269     const pg_missing_tracker_t &missing,
1270     bool touch_log,
1271     bool require_rollback,
1272     bool clear_divergent_priors,
1273     eversion_t dirty_to_dups,
1274     eversion_t dirty_from_dups,
1275     eversion_t write_from_dups,
1276     bool *rebuilt_missing_with_deletes,
1277     set<string> *log_keys_debug
1278     );
1279
1280   void read_log_and_missing(
1281     ObjectStore *store,
1282     ObjectStore::CollectionHandle& ch,
1283     ghobject_t pgmeta_oid,
1284     const pg_info_t &info,
1285     ostringstream &oss,
1286     bool tolerate_divergent_missing_log,
1287     bool debug_verify_stored_missing = false
1288     ) {
1289     return read_log_and_missing(
1290       store, ch, pgmeta_oid, info,
1291       log, missing, oss,
1292       tolerate_divergent_missing_log,
1293       &clear_divergent_priors,
1294       this,
1295       (pg_log_debug ? &log_keys_debug : nullptr),
1296       debug_verify_stored_missing);
1297   }
1298
1299   template <typename missing_type>
1300   static void read_log_and_missing(
1301     ObjectStore *store,
1302     ObjectStore::CollectionHandle &ch,
1303     ghobject_t pgmeta_oid,
1304     const pg_info_t &info,
1305     IndexedLog &log,
1306     missing_type &missing,
1307     ostringstream &oss,
1308     bool tolerate_divergent_missing_log,
1309     bool *clear_divergent_priors = nullptr,
1310     const DoutPrefixProvider *dpp = nullptr,
1311     set<string> *log_keys_debug = nullptr,
1312     bool debug_verify_stored_missing = false
1313     ) {
1314     ldpp_dout(dpp, 20) << "read_log_and_missing coll " << ch->cid
1315                        << " " << pgmeta_oid << dendl;
1316
1317     // legacy?
1318     struct stat st;
1319     int r = store->stat(ch, pgmeta_oid, &st);
1320     ceph_assert(r == 0);
1321     ceph_assert(st.st_size == 0);
1322
1323     // will get overridden below if it had been recorded
1324     eversion_t on_disk_can_rollback_to = info.last_update;
1325     eversion_t on_disk_rollback_info_trimmed_to = eversion_t();
1326     ObjectMap::ObjectMapIterator p = store->get_omap_iterator(ch,
1327                                                               pgmeta_oid);
1328     map<eversion_t, hobject_t> divergent_priors;
1329     bool must_rebuild = false;
1330     missing.may_include_deletes = false;
1331     list<pg_log_entry_t> entries;
1332     list<pg_log_dup_t> dups;
1333     if (p) {
1334       for (p->seek_to_first(); p->valid() ; p->next()) {
1335         // non-log pgmeta_oid keys are prefixed with _; skip those
1336         if (p->key()[0] == '_')
1337           continue;
1338         bufferlist bl = p->value();//Copy bufferlist before creating iterator
1339         auto bp = bl.cbegin();
1340         if (p->key() == "divergent_priors") {
1341           decode(divergent_priors, bp);
1342           ldpp_dout(dpp, 20) << "read_log_and_missing " << divergent_priors.size()
1343                              << " divergent_priors" << dendl;
1344           must_rebuild = true;
1345           debug_verify_stored_missing = false;
1346         } else if (p->key() == "can_rollback_to") {
1347           decode(on_disk_can_rollback_to, bp);
1348         } else if (p->key() == "rollback_info_trimmed_to") {
1349           decode(on_disk_rollback_info_trimmed_to, bp);
1350         } else if (p->key() == "may_include_deletes_in_missing") {
1351           missing.may_include_deletes = true;
1352         } else if (p->key().substr(0, 7) == string("missing")) {
1353           hobject_t oid;
1354           pg_missing_item item;
1355           decode(oid, bp);
1356           decode(item, bp);
1357           if (item.is_delete()) {
1358             ceph_assert(missing.may_include_deletes);
1359           }
1360           missing.add(oid, item.need, item.have, item.is_delete());
1361         } else if (p->key().substr(0, 4) == string("dup_")) {
1362           pg_log_dup_t dup;
1363           decode(dup, bp);
1364           if (!dups.empty()) {
1365             ceph_assert(dups.back().version < dup.version);
1366           }
1367           dups.push_back(dup);
1368         } else {
1369           pg_log_entry_t e;
1370           e.decode_with_checksum(bp);
1371           ldpp_dout(dpp, 20) << "read_log_and_missing " << e << dendl;
1372           if (!entries.empty()) {
1373             pg_log_entry_t last_e(entries.back());
1374             ceph_assert(last_e.version.version < e.version.version);
1375             ceph_assert(last_e.version.epoch <= e.version.epoch);
1376           }
1377           entries.push_back(e);
1378           if (log_keys_debug)
1379             log_keys_debug->insert(e.get_key_name());
1380         }
1381       }
1382     }
1383     log = IndexedLog(
1384       info.last_update,
1385       info.log_tail,
1386       on_disk_can_rollback_to,
1387       on_disk_rollback_info_trimmed_to,
1388       std::move(entries),
1389       std::move(dups));
1390
1391     if (must_rebuild || debug_verify_stored_missing) {
1392       // build missing
1393       if (debug_verify_stored_missing || info.last_complete < info.last_update) {
1394         ldpp_dout(dpp, 10)
1395           << "read_log_and_missing checking for missing items over interval ("
1396           << info.last_complete
1397           << "," << info.last_update << "]" << dendl;
1398
1399         set<hobject_t> did;
1400         set<hobject_t> checked;
1401         set<hobject_t> skipped;
1402         for (list<pg_log_entry_t>::reverse_iterator i = log.log.rbegin();
1403              i != log.log.rend();
1404              ++i) {
1405           if (!debug_verify_stored_missing && i->version <= info.last_complete) break;
1406           if (i->soid > info.last_backfill)
1407             continue;
1408           if (i->is_error())
1409             continue;
1410           if (did.count(i->soid)) continue;
1411           did.insert(i->soid);
1412
1413           if (!missing.may_include_deletes && i->is_delete())
1414             continue;
1415
1416           bufferlist bv;
1417           int r = store->getattr(
1418             ch,
1419             ghobject_t(i->soid, ghobject_t::NO_GEN, info.pgid.shard),
1420             OI_ATTR,
1421             bv);
1422           if (r >= 0) {
1423             object_info_t oi(bv);
1424             if (oi.version < i->version) {
1425               ldpp_dout(dpp, 15) << "read_log_and_missing  missing " << *i
1426                                  << " (have " << oi.version << ")" << dendl;
1427               if (debug_verify_stored_missing) {
1428                 auto miter = missing.get_items().find(i->soid);
1429                 ceph_assert(miter != missing.get_items().end());
1430                 ceph_assert(miter->second.need == i->version);
1431                 // the 'have' version is reset if an object is deleted,
1432                 // then created again
1433                 ceph_assert(miter->second.have == oi.version || miter->second.have == eversion_t());
1434                 checked.insert(i->soid);
1435               } else {
1436                 missing.add(i->soid, i->version, oi.version, i->is_delete());
1437               }
1438             }
1439           } else {
1440             ldpp_dout(dpp, 15) << "read_log_and_missing  missing " << *i << dendl;
1441             if (debug_verify_stored_missing) {
1442               auto miter = missing.get_items().find(i->soid);
1443               if (i->is_delete()) {
1444                 ceph_assert(miter == missing.get_items().end() ||
1445                        (miter->second.need == i->version &&
1446                         miter->second.have == eversion_t()));
1447               } else {
1448                 ceph_assert(miter != missing.get_items().end());
1449                 ceph_assert(miter->second.need == i->version);
1450                 ceph_assert(miter->second.have == eversion_t());
1451               }
1452               checked.insert(i->soid);
1453             } else {
1454               missing.add(i->soid, i->version, eversion_t(), i->is_delete());
1455             }
1456           }
1457         }
1458         if (debug_verify_stored_missing) {
1459           for (auto &&i: missing.get_items()) {
1460             if (checked.count(i.first))
1461               continue;
1462             if (i.first > info.last_backfill) {
1463               ldpp_dout(dpp, -1) << __func__ << ": invalid missing set entry "
1464                                 << "found before last_backfill: "
1465                                 << i.first << " " << i.second
1466                                 << " last_backfill = " << info.last_backfill
1467                                 << dendl;
1468               ceph_abort_msg("invalid missing set entry found");
1469             }
1470             bufferlist bv;
1471             int r = store->getattr(
1472               ch,
1473               ghobject_t(i.first, ghobject_t::NO_GEN, info.pgid.shard),
1474               OI_ATTR,
1475               bv);
1476             if (r >= 0) {
1477               object_info_t oi(bv);
1478               ceph_assert(oi.version == i.second.have || eversion_t() == i.second.have);
1479             } else {
1480               ceph_assert(i.second.is_delete() || eversion_t() == i.second.have);
1481             }
1482           }
1483         } else {
1484           ceph_assert(must_rebuild);
1485           for (map<eversion_t, hobject_t>::reverse_iterator i =
1486                  divergent_priors.rbegin();
1487                i != divergent_priors.rend();
1488                ++i) {
1489             if (i->first <= info.last_complete) break;
1490             if (i->second > info.last_backfill)
1491               continue;
1492             if (did.count(i->second)) continue;
1493             did.insert(i->second);
1494             bufferlist bv;
1495             int r = store->getattr(
1496               ch,
1497               ghobject_t(i->second, ghobject_t::NO_GEN, info.pgid.shard),
1498               OI_ATTR,
1499               bv);
1500             if (r >= 0) {
1501               object_info_t oi(bv);
1502               /**
1503                  * 1) we see this entry in the divergent priors mapping
1504                  * 2) we didn't see an entry for this object in the log
1505                  *
1506                  * From 1 & 2 we know that either the object does not exist
1507                  * or it is at the version specified in the divergent_priors
1508                  * map since the object would have been deleted atomically
1509                  * with the addition of the divergent_priors entry, an older
1510                  * version would not have been recovered, and a newer version
1511                  * would show up in the log above.
1512                  */
1513                 /**
1514                  * Unfortunately the assessment above is incorrect because of
1515                  * http://tracker.ceph.com/issues/17916 (we were incorrectly
1516                  * not removing the divergent_priors set from disk state!),
1517                  * so let's check that.
1518                  */
1519               if (oi.version > i->first && tolerate_divergent_missing_log) {
1520                 ldpp_dout(dpp, 0) << "read_log divergent_priors entry (" << *i
1521                                   << ") inconsistent with disk state (" <<  oi
1522                                   << "), assuming it is tracker.ceph.com/issues/17916"
1523                                   << dendl;
1524               } else {
1525                 ceph_assert(oi.version == i->first);
1526               }
1527             } else {
1528               ldpp_dout(dpp, 15) << "read_log_and_missing  missing " << *i << dendl;
1529               missing.add(i->second, i->first, eversion_t(), false);
1530             }
1531           }
1532         }
1533         if (clear_divergent_priors)
1534           (*clear_divergent_priors) = true;
1535       }
1536     }
1537
1538     if (!must_rebuild) {
1539       if (clear_divergent_priors)
1540         (*clear_divergent_priors) = false;
1541       missing.flush();
1542     }
1543     ldpp_dout(dpp, 10) << "read_log_and_missing done" << dendl;
1544   } // static read_log_and_missing
1545 }; // struct PGLog