fix: prohibit read commands during takeover

Author: BorysTheDev

src/server/main_service.cc

@@ -1057,7 +1057,10 @@ std::optional<ErrorReply> Service::VerifyCommandState(const CommandId* cid, CmdA
       allowed_by_state = false;
       break;
     case GlobalState::TAKEN_OVER:
-      allowed_by_state = !cid->IsWriteOnly();
+      // Only Admin commands are allowed
+      // we prohibit even read commands, because read commands running in pipeline can take a while
+      // to send all data to a client which leads to fail in takeover
+      allowed_by_state = dfly_cntx.conn()->IsPrivileged();
       break;
     default:
       break;