Recompute dataSize and numRecords if numbers don't make sense

Author: igorcanadi

src/mongo/db/storage/rocks/rocks_record_store.cpp

@@ -231,11 +231,10 @@ namespace mongo {
         // load metadata
         _numRecords.store(_counterManager->loadCounter(_numRecordsKey));
         _dataSize.store(_counterManager->loadCounter(_dataSizeKey));
-        invariant(_dataSize.load() >= 0);
-        invariant(_numRecords.load() >= 0);
 
-        if (!emptyCollection && !_counterManager->crashSafe() &&
-            _numRecords.load() < kCollectionScanOnCreationThreshold) {
+        if ((!emptyCollection && !_counterManager->crashSafe() &&
+             _numRecords.load() < kCollectionScanOnCreationThreshold) ||
+            _numRecords.load() < 0 || _dataSize.load() < 0) {
             LOG(1) << "doing scan of collection " << ns << " to get info";
 
             _numRecords.store(0);
@@ -306,14 +305,16 @@ namespace mongo {
 
     long long RocksRecordStore::dataSize(OperationContext* txn) const {
         RocksRecoveryUnit* ru = RocksRecoveryUnit::getRocksRecoveryUnit(txn);
-        return _dataSize.load(std::memory_order::memory_order_relaxed) +
-               ru->getDeltaCounter(_dataSizeKey);
+        return std::max(_dataSize.load(std::memory_order::memory_order_relaxed) +
+                            ru->getDeltaCounter(_dataSizeKey),
+                        static_cast<long long>(0));
     }
 
     long long RocksRecordStore::numRecords(OperationContext* txn) const {
         RocksRecoveryUnit* ru = RocksRecoveryUnit::getRocksRecoveryUnit( txn );
-        return _numRecords.load(std::memory_order::memory_order_relaxed) +
-            ru->getDeltaCounter(_numRecordsKey);
+        return std::max(_numRecords.load(std::memory_order::memory_order_relaxed) +
+                            ru->getDeltaCounter(_numRecordsKey),
+                        static_cast<long long>(0));
     }
 
     bool RocksRecordStore::cappedAndNeedDelete(long long dataSizeDelta,