From f545f2293e913d40a3d653ba50aea151f74feb02 Mon Sep 17 00:00:00 2001
From: Vyacheslav Napadovsky <napadovskiy@gmail.com>
Date: Mon, 7 Sep 2020 23:04:43 +0300
Subject: [PATCH] Make MMapMemoryAllocator map files in read-only (O_RDONLY)
 mode. Mapping with O_RDWR will cause copy_up across Docker layers.

---
 include/engine/datafacade/mmap_memory_allocator.hpp | 2 +-
 src/engine/datafacade/mmap_memory_allocator.cpp     | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/engine/datafacade/mmap_memory_allocator.hpp b/include/engine/datafacade/mmap_memory_allocator.hpp
index 60df71e90..fc4b4e24a 100644
--- a/include/engine/datafacade/mmap_memory_allocator.hpp
+++ b/include/engine/datafacade/mmap_memory_allocator.hpp
@@ -33,7 +33,7 @@ class MMapMemoryAllocator : public ContiguousBlockAllocator
 
   private:
     storage::SharedDataIndex index;
-    std::vector<boost::iostreams::mapped_file> mapped_memory_files;
+    std::vector<boost::iostreams::mapped_file_source> mapped_memory_files;
     std::string rtree_filename;
 };
 
diff --git a/src/engine/datafacade/mmap_memory_allocator.cpp b/src/engine/datafacade/mmap_memory_allocator.cpp
index fd87cc42a..38038656c 100644
--- a/src/engine/datafacade/mmap_memory_allocator.cpp
+++ b/src/engine/datafacade/mmap_memory_allocator.cpp
@@ -52,11 +52,11 @@ MMapMemoryAllocator::MMapMemoryAllocator(const storage::StorageConfig &config)
         {
             std::unique_ptr<storage::BaseDataLayout> layout =
                 std::make_unique<storage::TarDataLayout>();
-            boost::iostreams::mapped_file mapped_memory_file;
-            util::mmapFile<char>(file.second, mapped_memory_file);
+            boost::iostreams::mapped_file_source mapped_memory_file;
+            auto data = util::mmapFile<char>(file.second, mapped_memory_file).data();
             mapped_memory_files.push_back(std::move(mapped_memory_file));
             storage::populateLayoutFromFile(file.second, *layout);
-            allocated_regions.push_back({mapped_memory_file.data(), std::move(layout)});
+            allocated_regions.push_back({const_cast<char *>(data), std::move(layout)});
         }
     }