bugfix in trans buffer

Author: mag1c-h

ucm/store/cache/cc/trans_buffer.cc

@@ -348,24 +348,28 @@ Status TransBuffer::Setup(const Config& config)
 TransBuffer::Handle TransBuffer::Get(const Detail::BlockId& blockId, size_t shardIdx)
 {
     auto iBucket = Hash(blockId, shardIdx);
+    bool owner = false;
     strategy_->BucketLock(iBucket);
-    auto iNode = FindAt(iBucket, blockId, shardIdx);
-    strategy_->BucketUnlock(iBucket);
-    if (iNode != invalidIndex) { return Handle{this, iNode, false}; }
+    auto iNode = FindAt(iBucket, blockId, shardIdx, owner);
+    if (iNode != invalidIndex) {
+        strategy_->BucketUnlock(iBucket);
+        return Handle{this, iNode, owner};
+    }
     iNode = Alloc(blockId, shardIdx);
-    strategy_->BucketLock(iBucket);
     MoveTo(iBucket, iNode);
     strategy_->BucketUnlock(iBucket);
     return Handle(this, iNode, true);
 }
 
-size_t TransBuffer::FindAt(size_t iBucket, const Detail::BlockId& blockId, size_t shardIdx)
+size_t TransBuffer::FindAt(size_t iBucket, const Detail::BlockId& blockId, size_t shardIdx,
+                           bool& owner)
 {
     auto iNode = strategy_->FirstAt(iBucket);
     while (iNode != invalidIndex) {
         auto meta = strategy_->MetaAt(iNode);
         strategy_->NodeLock(iNode);
         if (meta->block == blockId && meta->shard == shardIdx) {
+            owner = meta->reference == 0;
             ++meta->reference;
             strategy_->NodeUnlock(iNode);
             break;

ucm/store/cache/cc/trans_buffer.h

@@ -101,7 +101,7 @@ class TransBuffer {
     Handle Get(const Detail::BlockId& blockId, size_t shardIdx);
 
 private:
-    size_t FindAt(size_t iBucket, const Detail::BlockId& blockId, size_t shardIdx);
+    size_t FindAt(size_t iBucket, const Detail::BlockId& blockId, size_t shardIdx, bool& owner);
     size_t Alloc(const Detail::BlockId& blockId, size_t shardIdx);
     void MoveTo(size_t iBucket, size_t iNode);
     void Remove(size_t iNode);