ceph/src/osdc/ObjectCacher.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3 #ifndef CEPH_OBJECTCACHER_H
   4 #define CEPH_OBJECTCACHER_H
   5
   6 #include "include/types.h"
   7 #include "include/lru.h"
   8 #include "include/Context.h"
   9 #include "include/xlist.h"
  10
  11 #include "common/Cond.h"
  12 #include "common/Finisher.h"
  13 #include "common/Thread.h"
  14 #include "common/zipkin_trace.h"
  15
  16 #include "Objecter.h"
  17 #include "Striper.h"
  18
  19 class CephContext;
  20 class WritebackHandler;
  21 class PerfCounters;
  22
  23 enum {
  24   l_objectcacher_first = 25000,
  25
  26   l_objectcacher_cache_ops_hit, // ops we satisfy completely from cache
  27   l_objectcacher_cache_ops_miss, // ops we don't satisfy completely from cache
  28
  29   l_objectcacher_cache_bytes_hit, // bytes read directly from cache
  30
  31   l_objectcacher_cache_bytes_miss, // bytes we couldn't read directly
  32
  33                                    // from cache
  34
  35   l_objectcacher_data_read, // total bytes read out
  36   l_objectcacher_data_written, // bytes written to cache
  37   l_objectcacher_data_flushed, // bytes flushed to WritebackHandler
  38   l_objectcacher_overwritten_in_flush, // bytes overwritten while
  39                                        // flushing is in progress
  40
  41   l_objectcacher_write_ops_blocked, // total write ops we delayed due
  42                                     // to dirty limits
  43   l_objectcacher_write_bytes_blocked, // total number of write bytes
  44                                       // we delayed due to dirty
  45                                       // limits
  46   l_objectcacher_write_time_blocked, // total time in seconds spent
  47                                      // blocking a write due to dirty
  48                                      // limits
  49
  50   l_objectcacher_last,
  51 };
  52
  53 class ObjectCacher {
  54   PerfCounters *perfcounter;
  55  public:
  56   CephContext *cct;
  57   class Object;
  58   struct ObjectSet;
  59   class C_ReadFinish;
  60
  61   typedef void (*flush_set_callback_t) (void *p, ObjectSet *oset);
  62
  63   // read scatter/gather
  64   struct OSDRead {
  65     vector<ObjectExtent> extents;
  66     snapid_t snap;
  67     bufferlist *bl;
  68     int fadvise_flags;
  69     OSDRead(snapid_t s, bufferlist *b, int f)
  70       : snap(s), bl(b), fadvise_flags(f) {}
  71   };
  72
  73   OSDRead *prepare_read(snapid_t snap, bufferlist *b, int f) const {
  74     return new OSDRead(snap, b, f);
  75   }
  76
  77   // write scatter/gather
  78   struct OSDWrite {
  79     vector<ObjectExtent> extents;
  80     SnapContext snapc;
  81     bufferlist bl;
  82     ceph::real_time mtime;
  83     int fadvise_flags;
  84     ceph_tid_t journal_tid;
  85     OSDWrite(const SnapContext& sc, const bufferlist& b, ceph::real_time mt,
  86              int f, ceph_tid_t _journal_tid)
  87       : snapc(sc), bl(b), mtime(mt), fadvise_flags(f),
  88         journal_tid(_journal_tid) {}
  89   };
  90
  91   OSDWrite *prepare_write(const SnapContext& sc,
  92                           const bufferlist &b,
  93                           ceph::real_time mt,
  94                           int f,
  95                           ceph_tid_t journal_tid) const {
  96     return new OSDWrite(sc, b, mt, f, journal_tid);
  97   }
  98
  99
 100
 101   // ******* BufferHead *********
 102   class BufferHead : public LRUObject {
 103   public:
 104     // states
 105     static const int STATE_MISSING = 0;
 106     static const int STATE_CLEAN = 1;
 107     static const int STATE_ZERO = 2;   // NOTE: these are *clean* zeros
 108     static const int STATE_DIRTY = 3;
 109     static const int STATE_RX = 4;
 110     static const int STATE_TX = 5;
 111     static const int STATE_ERROR = 6; // a read error occurred
 112
 113   private:
 114     // my fields
 115     int state;
 116     int ref;
 117     struct {
 118       loff_t start, length;   // bh extent in object
 119     } ex;
 120     bool dontneed; //indicate bh don't need by anyone
 121     bool nocache; //indicate bh don't need by this caller
 122
 123   public:
 124     Object *ob;
 125     bufferlist  bl;
 126     ceph_tid_t last_write_tid;  // version of bh (if non-zero)
 127     ceph_tid_t last_read_tid;   // tid of last read op (if any)
 128     ceph::real_time last_write;
 129     SnapContext snapc;
 130     ceph_tid_t journal_tid;
 131     int error; // holds return value for failed reads
 132
 133     map<loff_t, list<Context*> > waitfor_read;
 134
 135     // cons
 136     explicit BufferHead(Object *o) :
 137       state(STATE_MISSING),
 138       ref(0),
 139       dontneed(false),
 140       nocache(false),
 141       ob(o),
 142       last_write_tid(0),
 143       last_read_tid(0),
 144       journal_tid(0),
 145       error(0) {
 146       ex.start = ex.length = 0;
 147     }
 148
 149     // extent
 150     loff_t start() const { return ex.start; }
 151     void set_start(loff_t s) { ex.start = s; }
 152     loff_t length() const { return ex.length; }
 153     void set_length(loff_t l) { ex.length = l; }
 154     loff_t end() const { return ex.start + ex.length; }
 155     loff_t last() const { return end() - 1; }
 156
 157     // states
 158     void set_state(int s) {
 159       if (s == STATE_RX || s == STATE_TX) get();
 160       if (state == STATE_RX || state == STATE_TX) put();
 161       state = s;
 162     }
 163     int get_state() const { return state; }
 164
 165     inline ceph_tid_t get_journal_tid() const {
 166       return journal_tid;
 167     }
 168     inline void set_journal_tid(ceph_tid_t _journal_tid) {
 169       journal_tid = _journal_tid;
 170     }
 171
 172     bool is_missing() const { return state == STATE_MISSING; }
 173     bool is_dirty() const { return state == STATE_DIRTY; }
 174     bool is_clean() const { return state == STATE_CLEAN; }
 175     bool is_zero() const { return state == STATE_ZERO; }
 176     bool is_tx() const { return state == STATE_TX; }
 177     bool is_rx() const { return state == STATE_RX; }
 178     bool is_error() const { return state == STATE_ERROR; }
 179
 180     // reference counting
 181     int get() {
 182       assert(ref >= 0);
 183       if (ref == 0) lru_pin();
 184       return ++ref;
 185     }
 186     int put() {
 187       assert(ref > 0);
 188       if (ref == 1) lru_unpin();
 189       --ref;
 190       return ref;
 191     }
 192
 193     void set_dontneed(bool v) {
 194       dontneed = v;
 195     }
 196     bool get_dontneed() const {
 197       return dontneed;
 198     }
 199
 200     void set_nocache(bool v) {
 201       nocache = v;
 202     }
 203     bool get_nocache() const {
 204       return nocache;
 205     }
 206
 207     inline bool can_merge_journal(BufferHead *bh) const {
 208       return (get_journal_tid() == bh->get_journal_tid());
 209     }
 210
 211     struct ptr_lt {
 212       bool operator()(const BufferHead* l, const BufferHead* r) const {
 213         const Object *lob = l->ob;
 214         const Object *rob = r->ob;
 215         const ObjectSet *loset = lob->oset;
 216         const ObjectSet *roset = rob->oset;
 217         if (loset != roset)
 218           return loset < roset;
 219         if (lob != rob)
 220           return lob < rob;
 221         if (l->start() != r->start())
 222           return l->start() < r->start();
 223         return l < r;
 224       }
 225     };
 226   };
 227
 228   // ******* Object *********
 229   class Object : public LRUObject {
 230   private:
 231     // ObjectCacher::Object fields
 232     int ref;
 233     ObjectCacher *oc;
 234     sobject_t oid;
 235     friend struct ObjectSet;
 236
 237   public:
 238     uint64_t object_no;
 239     ObjectSet *oset;
 240     xlist<Object*>::item set_item;
 241     object_locator_t oloc;
 242     uint64_t truncate_size, truncate_seq;
 243
 244     bool complete;
 245     bool exists;
 246
 247     map<loff_t, BufferHead*>     data;
 248
 249     ceph_tid_t last_write_tid;  // version of bh (if non-zero)
 250     ceph_tid_t last_commit_tid; // last update commited.
 251
 252     int dirty_or_tx;
 253
 254     map< ceph_tid_t, list<Context*> > waitfor_commit;
 255     xlist<C_ReadFinish*> reads;
 256
 257     Object(const Object&) = delete;
 258     Object& operator=(const Object&) = delete;
 259
 260     Object(ObjectCacher *_oc, sobject_t o, uint64_t ono, ObjectSet *os,
 261            object_locator_t& l, uint64_t ts, uint64_t tq) :
 262       ref(0),
 263       oc(_oc),
 264       oid(o), object_no(ono), oset(os), set_item(this), oloc(l),
 265       truncate_size(ts), truncate_seq(tq),
 266       complete(false), exists(true),
 267       last_write_tid(0), last_commit_tid(0),
 268       dirty_or_tx(0) {
 269       // add to set
 270       os->objects.push_back(&set_item);
 271     }
 272     ~Object() {
 273       reads.clear();
 274       assert(ref == 0);
 275       assert(data.empty());
 276       assert(dirty_or_tx == 0);
 277       set_item.remove_myself();
 278     }
 279
 280     sobject_t get_soid() const { return oid; }
 281     object_t get_oid() { return oid.oid; }
 282     snapid_t get_snap() { return oid.snap; }
 283     ObjectSet *get_object_set() const { return oset; }
 284     string get_namespace() { return oloc.nspace; }
 285     uint64_t get_object_number() const { return object_no; }
 286
 287     const object_locator_t& get_oloc() const { return oloc; }
 288     void set_object_locator(object_locator_t& l) { oloc = l; }
 289
 290     bool can_close() const {
 291       if (lru_is_expireable()) {
 292         assert(data.empty());
 293         assert(waitfor_commit.empty());
 294         return true;
 295       }
 296       return false;
 297     }
 298
 299     /**
 300      * Check buffers and waiters for consistency
 301      * - no overlapping buffers
 302      * - index in map matches BH
 303      * - waiters fall within BH
 304      */
 305     void audit_buffers();
 306
 307     /**
 308      * find first buffer that includes or follows an offset
 309      *
 310      * @param offset object byte offset
 311      * @return iterator pointing to buffer, or data.end()
 312      */
 313     map<loff_t,BufferHead*>::const_iterator data_lower_bound(loff_t offset) const {
 314       map<loff_t,BufferHead*>::const_iterator p = data.lower_bound(offset);
 315       if (p != data.begin() &&
 316           (p == data.end() || p->first > offset)) {
 317         --p;     // might overlap!
 318         if (p->first + p->second->length() <= offset)
 319           ++p;   // doesn't overlap.
 320       }
 321       return p;
 322     }
 323
 324     // bh
 325     // add to my map
 326     void add_bh(BufferHead *bh) {
 327       if (data.empty())
 328         get();
 329       assert(data.count(bh->start()) == 0);
 330       data[bh->start()] = bh;
 331     }
 332     void remove_bh(BufferHead *bh) {
 333       assert(data.count(bh->start()));
 334       data.erase(bh->start());
 335       if (data.empty())
 336         put();
 337     }
 338
 339     bool is_empty() const { return data.empty(); }
 340
 341     // mid-level
 342     BufferHead *split(BufferHead *bh, loff_t off);
 343     void merge_left(BufferHead *left, BufferHead *right);
 344     void try_merge_bh(BufferHead *bh);
 345
 346     bool is_cached(loff_t off, loff_t len) const;
 347     bool include_all_cached_data(loff_t off, loff_t len);
 348     int map_read(ObjectExtent &ex,
 349                  map<loff_t, BufferHead*>& hits,
 350                  map<loff_t, BufferHead*>& missing,
 351                  map<loff_t, BufferHead*>& rx,
 352                  map<loff_t, BufferHead*>& errors);
 353     BufferHead *map_write(ObjectExtent &ex, ceph_tid_t tid);
 354
 355     void replace_journal_tid(BufferHead *bh, ceph_tid_t tid);
 356     void truncate(loff_t s);
 357     void discard(loff_t off, loff_t len);
 358
 359     // reference counting
 360     int get() {
 361       assert(ref >= 0);
 362       if (ref == 0) lru_pin();
 363       return ++ref;
 364     }
 365     int put() {
 366       assert(ref > 0);
 367       if (ref == 1) lru_unpin();
 368       --ref;
 369       return ref;
 370     }
 371   };
 372
 373
 374   struct ObjectSet {
 375     void *parent;
 376
 377     inodeno_t ino;
 378     uint64_t truncate_seq, truncate_size;
 379
 380     int64_t poolid;
 381     xlist<Object*> objects;
 382
 383     int dirty_or_tx;
 384     bool return_enoent;
 385
 386     ObjectSet(void *p, int64_t _poolid, inodeno_t i)
 387       : parent(p), ino(i), truncate_seq(0),
 388         truncate_size(0), poolid(_poolid), dirty_or_tx(0),
 389         return_enoent(false) {}
 390
 391   };
 392
 393
 394   // ******* ObjectCacher *********
 395   // ObjectCacher fields
 396  private:
 397   WritebackHandler& writeback_handler;
 398   bool scattered_write;
 399
 400   string name;
 401   Mutex& lock;
 402
 403   uint64_t max_dirty, target_dirty, max_size, max_objects;
 404   ceph::timespan max_dirty_age;
 405   bool block_writes_upfront;
 406
 407   ZTracer::Endpoint trace_endpoint;
 408
 409   flush_set_callback_t flush_set_callback;
 410   void *flush_set_callback_arg;
 411
 412   // indexed by pool_id
 413   vector<ceph::unordered_map<sobject_t, Object*> > objects;
 414
 415   list<Context*> waitfor_read;
 416
 417   ceph_tid_t last_read_tid;
 418
 419   set<BufferHead*, BufferHead::ptr_lt> dirty_or_tx_bh;
 420   LRU   bh_lru_dirty, bh_lru_rest;
 421   LRU   ob_lru;
 422
 423   Cond flusher_cond;
 424   bool flusher_stop;
 425   void flusher_entry();
 426   class FlusherThread : public Thread {
 427     ObjectCacher *oc;
 428   public:
 429     explicit FlusherThread(ObjectCacher *o) : oc(o) {}
 430     void *entry() override {
 431       oc->flusher_entry();
 432       return 0;
 433     }
 434   } flusher_thread;
 435
 436   Finisher finisher;
 437
 438   // objects
 439   Object *get_object_maybe(sobject_t oid, object_locator_t &l) {
 440     // have it?
 441     if (((uint32_t)l.pool < objects.size()) &&
 442         (objects[l.pool].count(oid)))
 443       return objects[l.pool][oid];
 444     return NULL;
 445   }
 446
 447   Object *get_object(sobject_t oid, uint64_t object_no, ObjectSet *oset,
 448                      object_locator_t &l, uint64_t truncate_size,
 449                      uint64_t truncate_seq);
 450   void close_object(Object *ob);
 451
 452   // bh stats
 453   Cond  stat_cond;
 454
 455   loff_t stat_clean;
 456   loff_t stat_zero;
 457   loff_t stat_dirty;
 458   loff_t stat_rx;
 459   loff_t stat_tx;
 460   loff_t stat_missing;
 461   loff_t stat_error;
 462   loff_t stat_dirty_waiting;   // bytes that writers are waiting on to write
 463
 464   size_t stat_nr_dirty_waiters;
 465
 466   void verify_stats() const;
 467
 468   void bh_stat_add(BufferHead *bh);
 469   void bh_stat_sub(BufferHead *bh);
 470   loff_t get_stat_tx() const { return stat_tx; }
 471   loff_t get_stat_rx() const { return stat_rx; }
 472   loff_t get_stat_dirty() const { return stat_dirty; }
 473   loff_t get_stat_clean() const { return stat_clean; }
 474   loff_t get_stat_zero() const { return stat_zero; }
 475   loff_t get_stat_dirty_waiting() const { return stat_dirty_waiting; }
 476   size_t get_stat_nr_dirty_waiters() const { return stat_nr_dirty_waiters; }
 477
 478   void touch_bh(BufferHead *bh) {
 479     if (bh->is_dirty())
 480       bh_lru_dirty.lru_touch(bh);
 481     else
 482       bh_lru_rest.lru_touch(bh);
 483
 484     bh->set_dontneed(false);
 485     bh->set_nocache(false);
 486     touch_ob(bh->ob);
 487   }
 488   void touch_ob(Object *ob) {
 489     ob_lru.lru_touch(ob);
 490   }
 491   void bottouch_ob(Object *ob) {
 492     ob_lru.lru_bottouch(ob);
 493   }
 494
 495   // bh states
 496   void bh_set_state(BufferHead *bh, int s);
 497   void copy_bh_state(BufferHead *bh1, BufferHead *bh2) {
 498     bh_set_state(bh2, bh1->get_state());
 499   }
 500
 501   void mark_missing(BufferHead *bh) {
 502     bh_set_state(bh,BufferHead::STATE_MISSING);
 503   }
 504   void mark_clean(BufferHead *bh) {
 505     bh_set_state(bh, BufferHead::STATE_CLEAN);
 506   }
 507   void mark_zero(BufferHead *bh) {
 508     bh_set_state(bh, BufferHead::STATE_ZERO);
 509   }
 510   void mark_rx(BufferHead *bh) {
 511     bh_set_state(bh, BufferHead::STATE_RX);
 512   }
 513   void mark_tx(BufferHead *bh) {
 514     bh_set_state(bh, BufferHead::STATE_TX); }
 515   void mark_error(BufferHead *bh) {
 516     bh_set_state(bh, BufferHead::STATE_ERROR);
 517   }
 518   void mark_dirty(BufferHead *bh) {
 519     bh_set_state(bh, BufferHead::STATE_DIRTY);
 520     bh_lru_dirty.lru_touch(bh);
 521     //bh->set_dirty_stamp(ceph_clock_now());
 522   }
 523
 524   void bh_add(Object *ob, BufferHead *bh);
 525   void bh_remove(Object *ob, BufferHead *bh);
 526
 527   // io
 528   void bh_read(BufferHead *bh, int op_flags,
 529                const ZTracer::Trace &parent_trace);
 530   void bh_write(BufferHead *bh, const ZTracer::Trace &parent_trace);
 531   void bh_write_scattered(list<BufferHead*>& blist);
 532   void bh_write_adjacencies(BufferHead *bh, ceph::real_time cutoff,
 533                             int64_t *amount, int *max_count);
 534
 535   void trim();
 536   void flush(ZTracer::Trace *trace, loff_t amount=0);
 537
 538   /**
 539    * flush a range of buffers
 540    *
 541    * Flush any buffers that intersect the specified extent.  If len==0,
 542    * flush *all* buffers for the object.
 543    *
 544    * @param o object
 545    * @param off start offset
 546    * @param len extent length, or 0 for entire object
 547    * @return true if object was already clean/flushed.
 548    */
 549   bool flush(Object *o, loff_t off, loff_t len,
 550              ZTracer::Trace *trace);
 551   loff_t release(Object *o);
 552   void purge(Object *o);
 553
 554   int64_t reads_outstanding;
 555   Cond read_cond;
 556
 557   int _readx(OSDRead *rd, ObjectSet *oset, Context *onfinish,
 558              bool external_call, ZTracer::Trace *trace);
 559   void retry_waiting_reads();
 560
 561  public:
 562   void bh_read_finish(int64_t poolid, sobject_t oid, ceph_tid_t tid,
 563                       loff_t offset, uint64_t length,
 564                       bufferlist &bl, int r,
 565                       bool trust_enoent);
 566   void bh_write_commit(int64_t poolid, sobject_t oid,
 567                        vector<pair<loff_t, uint64_t> >& ranges,
 568                        ceph_tid_t t, int r);
 569
 570   class C_WriteCommit;
 571   class C_WaitForWrite;
 572
 573   void perf_start();
 574   void perf_stop();
 575
 576
 577
 578   ObjectCacher(CephContext *cct_, string name, WritebackHandler& wb, Mutex& l,
 579                flush_set_callback_t flush_callback,
 580                void *flush_callback_arg,
 581                uint64_t max_bytes, uint64_t max_objects,
 582                uint64_t max_dirty, uint64_t target_dirty, double max_age,
 583                bool block_writes_upfront);
 584   ~ObjectCacher();
 585
 586   void start() {
 587     flusher_thread.create("flusher");
 588   }
 589   void stop() {
 590     assert(flusher_thread.is_started());
 591     lock.Lock();  // hmm.. watch out for deadlock!
 592     flusher_stop = true;
 593     flusher_cond.Signal();
 594     lock.Unlock();
 595     flusher_thread.join();
 596   }
 597
 598
 599   class C_RetryRead;
 600
 601
 602   // non-blocking.  async.
 603
 604   /**
 605    * @note total read size must be <= INT_MAX, since
 606    * the return value is total bytes read
 607    */
 608   int readx(OSDRead *rd, ObjectSet *oset, Context *onfinish,
 609             ZTracer::Trace *parent_trace = nullptr);
 610   int writex(OSDWrite *wr, ObjectSet *oset, Context *onfreespace,
 611              ZTracer::Trace *parent_trace = nullptr);
 612   bool is_cached(ObjectSet *oset, vector<ObjectExtent>& extents,
 613                  snapid_t snapid);
 614
 615 private:
 616   // write blocking
 617   int _wait_for_write(OSDWrite *wr, uint64_t len, ObjectSet *oset,
 618                       ZTracer::Trace *trace, Context *onfreespace);
 619   void maybe_wait_for_writeback(uint64_t len, ZTracer::Trace *trace);
 620   bool _flush_set_finish(C_GatherBuilder *gather, Context *onfinish);
 621
 622 public:
 623   bool set_is_empty(ObjectSet *oset);
 624   bool set_is_cached(ObjectSet *oset);
 625   bool set_is_dirty_or_committing(ObjectSet *oset);
 626
 627   bool flush_set(ObjectSet *oset, Context *onfinish=0);
 628   bool flush_set(ObjectSet *oset, vector<ObjectExtent>& ex,
 629                  ZTracer::Trace *trace, Context *onfinish = 0);
 630   bool flush_all(Context *onfinish = 0);
 631
 632   void purge_set(ObjectSet *oset);
 633
 634   // returns # of bytes not released (ie non-clean)
 635   loff_t release_set(ObjectSet *oset);
 636   uint64_t release_all();
 637
 638   void discard_set(ObjectSet *oset, const vector<ObjectExtent>& ex);
 639
 640   /**
 641    * Retry any in-flight reads that get -ENOENT instead of marking
 642    * them zero, and get rid of any cached -ENOENTs.
 643    * After this is called and the cache's lock is unlocked,
 644    * any new requests will treat -ENOENT normally.
 645    */
 646   void clear_nonexistence(ObjectSet *oset);
 647
 648
 649   // cache sizes
 650   void set_max_dirty(uint64_t v) {
 651     max_dirty = v;
 652   }
 653   void set_target_dirty(int64_t v) {
 654     target_dirty = v;
 655   }
 656   void set_max_size(int64_t v) {
 657     max_size = v;
 658   }
 659   void set_max_dirty_age(double a) {
 660     max_dirty_age = make_timespan(a);
 661   }
 662   void set_max_objects(int64_t v) {
 663     max_objects = v;
 664   }
 665
 666
 667   // file functions
 668
 669   /*** async+caching (non-blocking) file interface ***/
 670   int file_is_cached(ObjectSet *oset, file_layout_t *layout,
 671                      snapid_t snapid, loff_t offset, uint64_t len) {
 672     vector<ObjectExtent> extents;
 673     Striper::file_to_extents(cct, oset->ino, layout, offset, len,
 674                              oset->truncate_size, extents);
 675     return is_cached(oset, extents, snapid);
 676   }
 677
 678   int file_read(ObjectSet *oset, file_layout_t *layout, snapid_t snapid,
 679                 loff_t offset, uint64_t len, bufferlist *bl, int flags,
 680                 Context *onfinish) {
 681     OSDRead *rd = prepare_read(snapid, bl, flags);
 682     Striper::file_to_extents(cct, oset->ino, layout, offset, len,
 683                              oset->truncate_size, rd->extents);
 684     return readx(rd, oset, onfinish);
 685   }
 686
 687   int file_write(ObjectSet *oset, file_layout_t *layout,
 688                  const SnapContext& snapc, loff_t offset, uint64_t len,
 689                  bufferlist& bl, ceph::real_time mtime, int flags) {
 690     OSDWrite *wr = prepare_write(snapc, bl, mtime, flags, 0);
 691     Striper::file_to_extents(cct, oset->ino, layout, offset, len,
 692                              oset->truncate_size, wr->extents);
 693     return writex(wr, oset, NULL);
 694   }
 695
 696   bool file_flush(ObjectSet *oset, file_layout_t *layout,
 697                   const SnapContext& snapc, loff_t offset, uint64_t len,
 698                   Context *onfinish) {
 699     vector<ObjectExtent> extents;
 700     Striper::file_to_extents(cct, oset->ino, layout, offset, len,
 701                              oset->truncate_size, extents);
 702     ZTracer::Trace trace;
 703     return flush_set(oset, extents, &trace, onfinish);
 704   }
 705 };
 706
 707
 708 inline ostream& operator<<(ostream &out, const ObjectCacher::BufferHead &bh)
 709 {
 710   out << "bh[ " << &bh << " "
 711       << bh.start() << "~" << bh.length()
 712       << " " << bh.ob
 713       << " (" << bh.bl.length() << ")"
 714       << " v " << bh.last_write_tid;
 715   if (bh.get_journal_tid() != 0) {
 716     out << " j " << bh.get_journal_tid();
 717   }
 718   if (bh.is_tx()) out << " tx";
 719   if (bh.is_rx()) out << " rx";
 720   if (bh.is_dirty()) out << " dirty";
 721   if (bh.is_clean()) out << " clean";
 722   if (bh.is_zero()) out << " zero";
 723   if (bh.is_missing()) out << " missing";
 724   if (bh.bl.length() > 0) out << " firstbyte=" << (int)bh.bl[0];
 725   if (bh.error) out << " error=" << bh.error;
 726   out << "]";
 727   out << " waiters = {";
 728   for (map<loff_t, list<Context*> >::const_iterator it
 729          = bh.waitfor_read.begin();
 730        it != bh.waitfor_read.end(); ++it) {
 731     out << " " << it->first << "->[";
 732     for (list<Context*>::const_iterator lit = it->second.begin();
 733          lit != it->second.end(); ++lit) {
 734          out << *lit << ", ";
 735     }
 736     out << "]";
 737   }
 738   out << "}";
 739   return out;
 740 }
 741
 742 inline ostream& operator<<(ostream &out, const ObjectCacher::ObjectSet &os)
 743 {
 744   return out << "objectset[" << os.ino
 745              << " ts " << os.truncate_seq << "/" << os.truncate_size
 746              << " objects " << os.objects.size()
 747              << " dirty_or_tx " << os.dirty_or_tx
 748              << "]";
 749 }
 750
 751 inline ostream& operator<<(ostream &out, const ObjectCacher::Object &ob)
 752 {
 753   out << "object["
 754       << ob.get_soid() << " oset " << ob.oset << dec
 755       << " wr " << ob.last_write_tid << "/" << ob.last_commit_tid;
 756
 757   if (ob.complete)
 758     out << " COMPLETE";
 759   if (!ob.exists)
 760     out << " !EXISTS";
 761
 762   out << "]";
 763   return out;
 764 }
 765
 766 #endif