C++ DiskLoc::toString方法代码示例

 bool Extent::validates(const DiskLoc diskLoc, vector<string>* errors) const {
     bool extentOk = true;
     if (magic != extentSignature) {
         if (errors) {
             StringBuilder sb;
             sb << "bad extent signature " << integerToHex(magic)
                 << " in extent " << diskLoc.toString();
             errors->push_back( sb.str() );
         }
         extentOk = false;
     }
     if (myLoc != diskLoc) {
         if (errors) {
             StringBuilder sb;
             sb << "extent " << diskLoc.toString()
                 << " self-pointer is " << myLoc.toString();
             errors->push_back( sb.str() );
         }
         extentOk = false;
     }
     if (firstRecord.isNull() != lastRecord.isNull()) {
         if (errors) {
             StringBuilder sb;
             if (firstRecord.isNull()) {
                 sb << "in extent " << diskLoc.toString()
                     << ", firstRecord is null but lastRecord is "
                     << lastRecord.toString();
             }
             else {
                 sb << "in extent " << diskLoc.toString()
                     << ", firstRecord is " << firstRecord.toString()
                     << " but lastRecord is null";
             }
             errors->push_back( sb.str() );
         }
         extentOk = false;
     }
     static const int minSize = 0x1000;
     if (length < minSize) {
         if (errors) {
             StringBuilder sb;
             sb << "length of extent " << diskLoc.toString()
                 << " is " << length
                 << ", which is less than minimum length of " << minSize;
             errors->push_back( sb.str() );
         }
         extentOk = false;
     }
     return extentOk;
 }

 bool Extent::validates(const DiskLoc diskLoc, BSONArrayBuilder* errors) {
     bool extentOk = true;
     if (magic != extentSignature) {
         if (errors) {
             StringBuilder sb;
             sb << "bad extent signature " << integerToHex(magic)
                 << " in extent " << diskLoc.toString();
             *errors << sb.str();
         }
         extentOk = false;
     }
     if (myLoc != diskLoc) {
         if (errors) {
             StringBuilder sb;
             sb << "extent " << diskLoc.toString()
                 << " self-pointer is " << myLoc.toString();
             *errors << sb.str();
         }
         extentOk = false;
     }
     if (firstRecord.isNull() != lastRecord.isNull()) {
         if (errors) {
             StringBuilder sb;
             if (firstRecord.isNull()) {
                 sb << "in extent " << diskLoc.toString()
                     << ", firstRecord is null but lastRecord is "
                     << lastRecord.toString();
             }
             else {
                 sb << "in extent " << diskLoc.toString()
                     << ", firstRecord is " << firstRecord.toString()
                     << " but lastRecord is null";
             }
             *errors << sb.str();
         }
         extentOk = false;
     }
     if (length < minSize()) {
         if (errors) {
             StringBuilder sb;
             sb << "length of extent " << diskLoc.toString()
                 << " is " << length
                 << ", which is less than minimum length of " << minSize();
             *errors << sb.str();
         }
         extentOk = false;
     }
     return extentOk;
 }

    bool CoveredIndexMatcher::matches( const BSONObj& key, const DiskLoc& recLoc,
                                       MatchDetails* details, bool keyUsable ) const {

        LOG(5) << "CoveredIndexMatcher::matches() " << key.toString() << ' ' << recLoc.toString() << ' ' << keyUsable << endl;

        dassert( key.isValid() );

        if ( details )
            details->resetOutput();

        if ( keyUsable ) {
            if ( !_keyMatcher.matches(key, details ) ) {
                return false;
            }
            bool needRecordForDetails = details && details->needRecord();
            if ( !_needRecord && !needRecordForDetails ) {
                return true;
            }
        }

        if ( details )
            details->setLoadedRecord( true );

        BSONObj obj = recLoc.obj();
        bool res =
            _docMatcher->matches( obj, details ) &&
            !isOrClauseDup( obj );
        LOG(5) << "CoveredIndexMatcher _docMatcher->matches() returns " << res << endl;
        return res;
    }

 void NamespaceDetails::cappedDumpDelInfo() {
     cout << "dl[0]: " << _deletedList[0].toString() << endl;
     for( DiskLoc z = _deletedList[0]; !z.isNull(); z = z.drec()->nextDeleted() ) {
         cout << "  drec:" << z.toString() << " dreclen:" << hex << z.drec()->lengthWithHeaders() <<
              " ext:" << z.drec()->myExtent(z)->myLoc.toString() << endl;
     }
     cout << "dl[1]: " << _deletedList[1].toString() << endl;
 }

    shared_ptr<Cursor> DataFileMgr::findAll(const StringData& ns, const DiskLoc &startLoc) {
        NamespaceDetails * d = nsdetails( ns );
        if ( ! d )
            return shared_ptr<Cursor>(new BasicCursor(DiskLoc()));

        DiskLoc loc = d->firstExtent();
        if ( loc.isNull() )
            return shared_ptr<Cursor>(new BasicCursor(DiskLoc()));
        Extent *e = getExtent(loc);

        DEBUGGING {
            out() << "listing extents for " << ns << endl;
            DiskLoc tmp = loc;
            set<DiskLoc> extents;

            while ( 1 ) {
                Extent *f = getExtent(tmp);
                out() << "extent: " << tmp.toString() << endl;
                extents.insert(tmp);
                tmp = f->xnext;
                if ( tmp.isNull() )
                    break;
                f = f->getNextExtent();
            }

            out() << endl;
            d->dumpDeleted(&extents);
        }

        if ( d->isCapped() )
            return shared_ptr<Cursor>( ForwardCappedCursor::make( d , startLoc ) );

        if ( !startLoc.isNull() )
            return shared_ptr<Cursor>(new BasicCursor( startLoc ));

        while ( e->firstRecord.isNull() && !e->xnext.isNull() ) {
            /* todo: if extent is empty, free it for reuse elsewhere.
               that is a bit complicated have to clean up the freelists.
            */
            RARELY out() << "info DFM::findAll(): extent " << loc.toString() << " was empty, skipping ahead. ns:" << ns << endl;
            // find a nonempty extent
            // it might be nice to free the whole extent here!  but have to clean up free recs then.
            e = e->getNextExtent();
        }
        return shared_ptr<Cursor>(new BasicCursor( e->firstRecord ));
    }

    void SimpleRecordStoreV1::addDeletedRec( OperationContext* txn, const DiskLoc& dloc ) {
        DeletedRecord* d = drec( dloc );

        DEBUGGING log() << "TEMP: add deleted rec " << dloc.toString() << ' ' << hex << d->extentOfs() << endl;

        int b = bucket(d->lengthWithHeaders());
        *txn->recoveryUnit()->writing(&d->nextDeleted()) = _details->deletedListEntry(b);
        _details->setDeletedListEntry(txn, b, dloc);
    }

 void BtreeBasedAccessMethod::removeOneKey(OperationContext* txn,
                                           const BSONObj& key,
                                           const DiskLoc& loc,
                                           bool dupsAllowed) {
     try {
         _newInterface->unindex(txn, key, loc, dupsAllowed);
     } catch (AssertionException& e) {
         log() << "Assertion failure: _unindex failed "
               << _descriptor->indexNamespace() << endl;
         log() << "Assertion failure: _unindex failed: " << e.what() << '\n';
         log() << "  key:" << key.toString() << '\n';
         log() << "  dl:" << loc.toString() << endl;
         logContext();
     }
 }

    bool BtreeBasedAccessMethod::removeOneKey(const BSONObj& key, const DiskLoc& loc) {
        bool ret = false;

        try {
            ret = _newInterface->unindex(key, loc);
        } catch (AssertionException& e) {
            problem() << "Assertion failure: _unindex failed "
                << _descriptor->indexNamespace() << endl;
            out() << "Assertion failure: _unindex failed: " << e.what() << '\n';
            out() << "  obj:" << loc.obj().toString() << '\n';
            out() << "  key:" << key.toString() << '\n';
            out() << "  dl:" << loc.toString() << endl;
            logContext();
        }

        return ret;
    }

    int BucketBasics::fullValidate(const DiskLoc& thisLoc, const BSONObj &order, int *unusedCount) {
        {
            bool f = false;
            assert( f = true );
            massert( 10281 , "assert is misdefined", f);
        }

        killCurrentOp.checkForInterrupt();
        assertValid(order, true);
//	if( bt_fv==0 )
//		return;

        if ( bt_dmp ) {
            out() << thisLoc.toString() << ' ';
            ((BtreeBucket *) this)->dump();
        }

        // keycount
        int kc = 0;

        for ( int i = 0; i < n; i++ ) {
            _KeyNode& kn = k(i);

            if ( kn.isUsed() ) {
                kc++;
            } else {
                if ( unusedCount ) {
                    ++( *unusedCount );
                }
            }
            if ( !kn.prevChildBucket.isNull() ) {
                DiskLoc left = kn.prevChildBucket;
                BtreeBucket *b = left.btree();
                wassert( b->parent == thisLoc );
                kc += b->fullValidate(kn.prevChildBucket, order, unusedCount);
            }
        }
        if ( !nextChild.isNull() ) {
            BtreeBucket *b = nextChild.btree();
            wassert( b->parent == thisLoc );
            kc += b->fullValidate(nextChild, order, unusedCount);
        }

        return kc;
    }

        string validateNS(const char *ns, NamespaceDetails *d, BSONObj *cmdObj) {
            bool scanData = true;
            if( cmdObj && cmdObj->hasElement("scandata") && !cmdObj->getBoolField("scandata") )
                scanData = false;
            bool valid = true;
            stringstream ss;
            ss << "\nvalidate\n";
            //ss << "  details: " << hex << d << " ofs:" << nsindex(ns)->detailsOffset(d) << dec << endl;
            if ( d->capped )
                ss << "  capped:" << d->capped << " max:" << d->max << '\n';

            ss << "  firstExtent:" << d->firstExtent.toString() << " ns:" << d->firstExtent.ext()->nsDiagnostic.toString()<< '\n';
            ss << "  lastExtent:" << d->lastExtent.toString()    << " ns:" << d->lastExtent.ext()->nsDiagnostic.toString() << '\n';
            try {
                d->firstExtent.ext()->assertOk();
                d->lastExtent.ext()->assertOk();

                DiskLoc el = d->firstExtent;
                int ne = 0;
                while( !el.isNull() ) {
                    Extent *e = el.ext();
                    e->assertOk();
                    el = e->xnext;
                    ne++;
                    killCurrentOp.checkForInterrupt();
                }
                ss << "  # extents:" << ne << '\n';
            }
            catch (...) {
                valid=false;
                ss << " extent asserted ";
            }

            ss << "  datasize?:" << d->stats.datasize << " nrecords?:" << d->stats.nrecords << " lastExtentSize:" << d->lastExtentSize << '\n';
            ss << "  padding:" << d->paddingFactor << '\n';
            try {

                try {
                    ss << "  first extent:\n";
                    d->firstExtent.ext()->dump(ss);
                    valid = valid && d->firstExtent.ext()->validates();
                }
                catch (...) {
                    ss << "\n    exception firstextent\n" << endl;
                }

                set<DiskLoc> recs;
                if( scanData ) {
                    shared_ptr<Cursor> c = theDataFileMgr.findAll(ns);
                    int n = 0;
                    long long len = 0;
                    long long nlen = 0;
                    int outOfOrder = 0;
                    DiskLoc cl_last;
                    while ( c->ok() ) {
                        n++;

                        DiskLoc cl = c->currLoc();
                        if ( n < 1000000 )
                            recs.insert(cl);
                        if ( d->capped ) {
                            if ( cl < cl_last )
                                outOfOrder++;
                            cl_last = cl;
                        }

                        Record *r = c->_current();
                        len += r->lengthWithHeaders;
                        nlen += r->netLength();
                        c->advance();
                    }
                    if ( d->capped && !d->capLooped() ) {
                        ss << "  capped outOfOrder:" << outOfOrder;
                        if ( outOfOrder > 1 ) {
                            valid = false;
                            ss << " ???";
                        }
                        else ss << " (OK)";
                        ss << '\n';
                    }
                    ss << "  " << n << " objects found, nobj:" << d->stats.nrecords << '\n';
                    ss << "  " << len << " bytes data w/headers\n";
                    ss << "  " << nlen << " bytes data wout/headers\n";
                }

                ss << "  deletedList: ";
                for ( int i = 0; i < Buckets; i++ ) {
                    ss << (d->deletedList[i].isNull() ? '0' : '1');
                }
                ss << endl;
                int ndel = 0;
                long long delSize = 0;
                int incorrect = 0;
                for ( int i = 0; i < Buckets; i++ ) {
                    DiskLoc loc = d->deletedList[i];
                    try {
                        int k = 0;
                        while ( !loc.isNull() ) {
                            if ( recs.count(loc) )
                                incorrect++;
//.........这里部分代码省略.........

    /* must call this on a delete so we clean up the cursors. */
    void ClientCursor::aboutToDelete(const DiskLoc& dl) {
        recursive_scoped_lock lock(ccmutex);

        Database *db = cc().database();
        assert(db);

        aboutToDeleteForSharding( db , dl );

        CCByLoc& bl = db->ccByLoc;
        CCByLoc::iterator j = bl.lower_bound(ByLocKey::min(dl));
        CCByLoc::iterator stop = bl.upper_bound(ByLocKey::max(dl));
        if ( j == stop )
            return;

        vector<ClientCursor*> toAdvance;

        while ( 1 ) {
            toAdvance.push_back(j->second);
            DEV assert( j->first.loc == dl );
            ++j;
            if ( j == stop )
                break;
        }

        if( toAdvance.size() >= 3000 ) {
            log() << "perf warning MPW101: " << toAdvance.size() << " cursors for one diskloc "
                  << dl.toString()
                  << ' ' << toAdvance[1000]->_ns
                  << ' ' << toAdvance[2000]->_ns
                  << ' ' << toAdvance[1000]->_pinValue
                  << ' ' << toAdvance[2000]->_pinValue
                  << ' ' << toAdvance[1000]->_pos
                  << ' ' << toAdvance[2000]->_pos
                  << ' ' << toAdvance[1000]->_idleAgeMillis
                  << ' ' << toAdvance[2000]->_idleAgeMillis
                  << ' ' << toAdvance[1000]->_doingDeletes
                  << ' ' << toAdvance[2000]->_doingDeletes
                  << endl;
            //wassert( toAdvance.size() < 5000 );
        }

        for ( vector<ClientCursor*>::iterator i = toAdvance.begin(); i != toAdvance.end(); ++i ) {
            ClientCursor* cc = *i;
            wassert(cc->_db == db);

            if ( cc->_doingDeletes ) continue;

            Cursor *c = cc->_c.get();
            if ( c->capped() ) {
                /* note we cannot advance here. if this condition occurs, writes to the oplog
                   have "caught" the reader.  skipping ahead, the reader would miss postentially
                   important data.
                   */
                delete cc;
                continue;
            }

            c->checkLocation();
            DiskLoc tmp1 = c->refLoc();
            if ( tmp1 != dl ) {
                // This might indicate a failure to call ClientCursor::updateLocation() but it can
                // also happen during correct operation, see SERVER-2009.
                problem() << "warning: cursor loc " << tmp1 << " does not match byLoc position " << dl << " !" << endl;
            }
            else {
                c->advance();
            }
            if ( c->eof() ) {
                // advanced to end
                // leave ClientCursor in place so next getMore doesn't fail
                // still need to mark new location though
                cc->updateLocation();
            }
            else {
                wassert( c->refLoc() != dl );
                cc->updateLocation();
            }
        }
    }

    /* must call this on a delete so we clean up the cursors. */
    void ClientCursor::aboutToDelete(const StringData& ns,
                                     const NamespaceDetails* nsd,
                                     const DiskLoc& dl) {
        // Begin cursor-only
        NoPageFaultsAllowed npfa;
        // End cursor-only

        recursive_scoped_lock lock(ccmutex);

        Database *db = cc().database();
        verify(db);

        aboutToDeleteForSharding( ns, db, nsd, dl );

        // Check our non-cached active runner list.
        for (set<Runner*>::iterator it = nonCachedRunners.begin(); it != nonCachedRunners.end();
             ++it) {

            Runner* runner = *it;
            if (0 == ns.compare(runner->ns())) {
                runner->invalidate(dl);
            }
        }

        // TODO: This requires optimization.  We walk through *all* CCs and send the delete to every
        // CC open on the db we're deleting from.  We could:
        // 1. Map from ns to open runners,
        // 2. Map from ns -> (a map of DiskLoc -> runners who care about that DL)
        //
        // We could also queue invalidations somehow and have them processed later in the runner's
        // read locks.
        for (CCById::const_iterator it = clientCursorsById.begin(); it != clientCursorsById.end();
             ++it) {

            ClientCursor* cc = it->second;
            // We're only interested in cursors over one db.
            if (cc->_db != db) { continue; }
            if (NULL == cc->_runner.get()) { continue; }
            cc->_runner->invalidate(dl);
        }

        // Begin cursor-only.  Only cursors that are in ccByLoc are processed here.
        CCByLoc& bl = db->ccByLoc();
        CCByLoc::iterator j = bl.lower_bound(ByLocKey::min(dl));
        CCByLoc::iterator stop = bl.upper_bound(ByLocKey::max(dl));
        if ( j == stop )
            return;

        vector<ClientCursor*> toAdvance;

        while ( 1 ) {
            toAdvance.push_back(j->second);
            DEV verify( j->first.loc == dl );
            ++j;
            if ( j == stop )
                break;
        }

        if( toAdvance.size() >= 3000 ) {
            log() << "perf warning MPW101: " << toAdvance.size() << " cursors for one diskloc "
                  << dl.toString()
                  << ' ' << toAdvance[1000]->_ns
                  << ' ' << toAdvance[2000]->_ns
                  << ' ' << toAdvance[1000]->_pinValue
                  << ' ' << toAdvance[2000]->_pinValue
                  << ' ' << toAdvance[1000]->_pos
                  << ' ' << toAdvance[2000]->_pos
                  << ' ' << toAdvance[1000]->_idleAgeMillis
                  << ' ' << toAdvance[2000]->_idleAgeMillis
                  << ' ' << toAdvance[1000]->_doingDeletes
                  << ' ' << toAdvance[2000]->_doingDeletes
                  << endl;
            //wassert( toAdvance.size() < 5000 );
        }

        for ( vector<ClientCursor*>::iterator i = toAdvance.begin(); i != toAdvance.end(); ++i ) {
            ClientCursor* cc = *i;
            wassert(cc->_db == db);

            if ( cc->_doingDeletes ) continue;

            Cursor *c = cc->_c.get();
            if ( c->capped() ) {
                /* note we cannot advance here. if this condition occurs, writes to the oplog
                   have "caught" the reader.  skipping ahead, the reader would miss postentially
                   important data.
                   */
                delete cc;
                continue;
            }

            c->recoverFromYield();
            DiskLoc tmp1 = c->refLoc();
            if ( tmp1 != dl ) {
                // This might indicate a failure to call ClientCursor::prepareToYield() but it can
                // also happen during correct operation, see SERVER-2009.
                problem() << "warning: cursor loc " << tmp1 << " does not match byLoc position " << dl << " !" << endl;
            }
            else {
//.........这里部分代码省略.........

    Status RecordStoreV1Base::validate( OperationContext* txn,
                                        bool full, bool scanData,
                                        ValidateAdaptor* adaptor,
                                        ValidateResults* results, BSONObjBuilder* output ) const {

        // 1) basic status that require no iteration
        // 2) extent level info
        // 3) check extent start and end
        // 4) check each non-deleted record
        // 5) check deleted list

        // -------------

        // 1111111111111111111
        if ( isCapped() ){
            output->appendBool("capped", true);
            output->appendNumber("max", _details->maxCappedDocs());
        }

        output->appendNumber("datasize", _details->dataSize());
        output->appendNumber("nrecords", _details->numRecords());
        output->appendNumber("lastExtentSize", _details->lastExtentSize(txn));
        output->appendNumber("padding", _details->paddingFactor());

        if ( _details->firstExtent(txn).isNull() )
            output->append( "firstExtent", "null" );
        else
            output->append( "firstExtent",
                            str::stream() << _details->firstExtent(txn).toString()
                            << " ns:"
                            << _getExtent( txn, _details->firstExtent(txn) )->nsDiagnostic.toString());
        if ( _details->lastExtent(txn).isNull() )
            output->append( "lastExtent", "null" );
        else
            output->append( "lastExtent", str::stream() << _details->lastExtent(txn).toString()
                            << " ns:"
                            << _getExtent( txn, _details->lastExtent(txn) )->nsDiagnostic.toString());

        // 22222222222222222222222222
        { // validate extent basics
            BSONArrayBuilder extentData;
            int extentCount = 0;
            DiskLoc extentDiskLoc;
            try {
                if ( !_details->firstExtent(txn).isNull() ) {
                    _getExtent( txn, _details->firstExtent(txn) )->assertOk();
                    _getExtent( txn, _details->lastExtent(txn) )->assertOk();
                }

                extentDiskLoc = _details->firstExtent(txn);
                while (!extentDiskLoc.isNull()) {
                    Extent* thisExtent = _getExtent( txn, extentDiskLoc );
                    if (full) {
                        extentData << thisExtent->dump();
                    }
                    if (!thisExtent->validates(extentDiskLoc, &results->errors)) {
                        results->valid = false;
                    }
                    DiskLoc nextDiskLoc = thisExtent->xnext;
                    
                    if (extentCount > 0 && !nextDiskLoc.isNull()
                        &&  _getExtent( txn, nextDiskLoc )->xprev != extentDiskLoc) {
                        StringBuilder sb;
                        sb << "'xprev' pointer " << _getExtent( txn, nextDiskLoc )->xprev.toString()
                           << " in extent " << nextDiskLoc.toString()
                           << " does not point to extent " << extentDiskLoc.toString();
                        results->errors.push_back( sb.str() );
                        results->valid = false;
                    }
                    if (nextDiskLoc.isNull() && extentDiskLoc != _details->lastExtent(txn)) {
                        StringBuilder sb;
                        sb << "'lastExtent' pointer " << _details->lastExtent(txn).toString()
                           << " does not point to last extent in list " << extentDiskLoc.toString();
                        results->errors.push_back( sb.str() );
                        results->valid = false;
                    }
                    extentDiskLoc = nextDiskLoc;
                    extentCount++;
                    txn->checkForInterrupt();
                }
            }
            catch (const DBException& e) {
                StringBuilder sb;
                sb << "exception validating extent " << extentCount
                   << ": " << e.what();
                results->errors.push_back( sb.str() );
                results->valid = false;
                return Status::OK();
            }
            output->append("extentCount", extentCount);

            if ( full )
                output->appendArray( "extents" , extentData.arr() );

        }

        try {
            // 333333333333333333333333333
            bool testingLastExtent = false;
            try {
//.........这里部分代码省略.........

        void validateNS(const char *ns, NamespaceDetails *d, const BSONObj& cmdObj, BSONObjBuilder& result) {
            const bool full = cmdObj["full"].trueValue();
            const bool scanData = full || cmdObj["scandata"].trueValue();

            bool valid = true;
            BSONArrayBuilder errors; // explanation(s) for why valid = false
            if ( d->isCapped() ){
                result.append("capped", d->isCapped());
                result.appendNumber("max", d->maxCappedDocs());
            }

            result.append("firstExtent", str::stream() << d->firstExtent.toString() << " ns:" << d->firstExtent.ext()->nsDiagnostic.toString());
            result.append( "lastExtent", str::stream() <<  d->lastExtent.toString() << " ns:" <<  d->lastExtent.ext()->nsDiagnostic.toString());
            
            BSONArrayBuilder extentData;

            try {
                d->firstExtent.ext()->assertOk();
                d->lastExtent.ext()->assertOk();

                DiskLoc el = d->firstExtent;
                int ne = 0;
                while( !el.isNull() ) {
                    Extent *e = el.ext();
                    e->assertOk();
                    el = e->xnext;
                    ne++;
                    if ( full )
                        extentData << e->dump();
                    
                    killCurrentOp.checkForInterrupt();
                }
                result.append("extentCount", ne);
            }
            catch (...) {
                valid=false;
                errors << "extent asserted";
            }

            if ( full )
                result.appendArray( "extents" , extentData.arr() );

            
            result.appendNumber("datasize", d->stats.datasize);
            result.appendNumber("nrecords", d->stats.nrecords);
            result.appendNumber("lastExtentSize", d->lastExtentSize);
            result.appendNumber("padding", d->paddingFactor());
            

            try {

                try {
                    result.append("firstExtentDetails", d->firstExtent.ext()->dump());

                    valid = valid && d->firstExtent.ext()->validates() && 
                        d->firstExtent.ext()->xprev.isNull();
                }
                catch (...) {
                    errors << "exception firstextent";
                    valid = false;
                }

                set<DiskLoc> recs;
                if( scanData ) {
                    shared_ptr<Cursor> c = theDataFileMgr.findAll(ns);
                    int n = 0;
                    int nInvalid = 0;
                    long long len = 0;
                    long long nlen = 0;
                    int outOfOrder = 0;
                    DiskLoc cl_last;
                    while ( c->ok() ) {
                        n++;

                        DiskLoc cl = c->currLoc();
                        if ( n < 1000000 )
                            recs.insert(cl);
                        if ( d->isCapped() ) {
                            if ( cl < cl_last )
                                outOfOrder++;
                            cl_last = cl;
                        }

                        Record *r = c->_current();
                        len += r->lengthWithHeaders();
                        nlen += r->netLength();

                        if (full){
                            BSONObj obj = BSONObj::make(r);
                            if (!obj.isValid() || !obj.valid()){ // both fast and deep checks
                                valid = false;
                                if (nInvalid == 0) // only log once;
                                    errors << "invalid bson object detected (see logs for more info)";

                                nInvalid++;
                                if (strcmp("_id", obj.firstElementFieldName()) == 0){
                                    try {
                                        obj.firstElement().validate(); // throws on error
                                        log() << "Invalid bson detected in " << ns << " with _id: " << obj.firstElement().toString(false) << endl;
                                    }
//.........这里部分代码省略.........

    DiskLoc SimpleRecordStoreV1::_allocFromExistingExtents( OperationContext* txn,
                                                            int lenToAlloc ) {
        // align size up to a multiple of 4
        lenToAlloc = (lenToAlloc + (4-1)) & ~(4-1);

        freelistAllocs.increment();
        DiskLoc loc;
        {
            DiskLoc *prev = 0;
            DiskLoc *bestprev = 0;
            DiskLoc bestmatch;
            int bestmatchlen = INT_MAX; // sentinel meaning we haven't found a record big enough
            int b = bucket(lenToAlloc);
            DiskLoc cur = _details->deletedListEntry(b);
            
            int extra = 5; // look for a better fit, a little.
            int chain = 0;
            while ( 1 ) {
                { // defensive check
                    int fileNumber = cur.a();
                    int fileOffset = cur.getOfs();
                    if (fileNumber < -1 || fileNumber >= 100000 || fileOffset < 0) {
                        StringBuilder sb;
                        sb << "Deleted record list corrupted in collection " << _ns
                           << ", bucket " << b
                           << ", link number " << chain
                           << ", invalid link is " << cur.toString()
                           << ", throwing Fatal Assertion";
                        log() << sb.str() << endl;
                        fassertFailed(16469);
                    }
                }
                if ( cur.isNull() ) {
                    // move to next bucket.  if we were doing "extra", just break
                    if ( bestmatchlen < INT_MAX )
                        break;

                    if ( chain > 0 ) {
                        // if we looked at things in the right bucket, but they were not suitable
                        freelistBucketExhausted.increment();
                    }

                    b++;
                    if ( b > MaxBucket ) {
                        // out of space. alloc a new extent.
                        freelistIterations.increment( 1 + chain );
                        return DiskLoc();
                    }
                    cur = _details->deletedListEntry(b);
                    prev = 0;
                    continue;
                }
                DeletedRecord *r = drec(cur);
                if ( r->lengthWithHeaders() >= lenToAlloc &&
                     r->lengthWithHeaders() < bestmatchlen ) {
                    bestmatchlen = r->lengthWithHeaders();
                    bestmatch = cur;
                    bestprev = prev;
                    if (r->lengthWithHeaders() == lenToAlloc)
                        // exact match, stop searching
                        break;
                }
                if ( bestmatchlen < INT_MAX && --extra <= 0 )
                    break;
                if ( ++chain > 30 && b <= MaxBucket ) {
                    // too slow, force move to next bucket to grab a big chunk
                    //b++;
                    freelistIterations.increment( chain );
                    chain = 0;
                    cur.Null();
                }
                else {
                    cur = r->nextDeleted();
                    prev = &r->nextDeleted();
                }
            }

            // unlink ourself from the deleted list
            DeletedRecord *bmr = drec(bestmatch);
            if ( bestprev ) {
                *txn->recoveryUnit()->writing(bestprev) = bmr->nextDeleted();
            }
            else {
                // should be the front of a free-list
                int myBucket = bucket(bmr->lengthWithHeaders());
                invariant( _details->deletedListEntry(myBucket) == bestmatch );
                _details->setDeletedListEntry(txn, myBucket, bmr->nextDeleted());
            }
            *txn->recoveryUnit()->writing(&bmr->nextDeleted()) = DiskLoc().setInvalid(); // defensive.
            invariant(bmr->extentOfs() < bestmatch.getOfs());

            freelistIterations.increment( 1 + chain );
            loc = bestmatch;
        }

        if ( loc.isNull() )
            return loc;

        // determine if we should chop up

//.........这里部分代码省略.........