consensus: don't call GetBlockPos in ReadBlockFromDisk without lock

Author: jonatack

src/node/blockstorage.cpp

@@ -394,18 +394,14 @@ bool ReadBlockFromDisk(CBlock& block, const FlatFilePos& pos, const Consensus::P
 
 bool ReadBlockFromDisk(CBlock& block, const CBlockIndex* pindex, const Consensus::Params& consensusParams)
 {
-    FlatFilePos blockPos;
-    {
-        LOCK(cs_main);
-        blockPos = pindex->GetBlockPos();
-    }
+    const FlatFilePos block_pos{WITH_LOCK(cs_main, return pindex->GetBlockPos())};
 
-    if (!ReadBlockFromDisk(block, blockPos, consensusParams)) {
+    if (!ReadBlockFromDisk(block, block_pos, consensusParams)) {
         return false;
     }
     if (block.GetHash() != pindex->GetBlockHash()) {
         return error("ReadBlockFromDisk(CBlock&, CBlockIndex*): GetHash() doesn't match index for %s at %s",
-                     pindex->ToString(), pindex->GetBlockPos().ToString());
+                     pindex->ToString(), block_pos.ToString());
     }
     return true;
 }