Fix race

src/Interpreters/Cache/FileSegment.cpp

@@ -469,7 +469,7 @@ bool FileSegment::reserve(size_t size_to_reserve)
             /// No lock is required because reserved size is always
             /// mananaged (read/modified) by the downloader only
             /// or in isLastHolder() case.
-            /// Therefore, atomic must not be used, it will only hide possible races.
+            /// It is made atomic because of getInfoForLog.
             reserved_size += size_to_reserve;
         }
     }

src/Interpreters/Cache/FileSegment.h

@@ -318,7 +318,7 @@ private:
 
     /// downloaded_size should always be less or equal to reserved_size
     std::atomic<size_t> downloaded_size = 0;
-    size_t reserved_size = 0;
+    std::atomic<size_t> reserved_size = 0;
 
     /// global locking order rule:
     /// 1. cache lock