support compiling with custom ext2fs

Signed-off-by: yuchen.cc <yuchen.cc@alibaba-inc.com>

CMake/Findext2fs.cmake

@@ -0,0 +1,15 @@
+include(FetchContent)
+set(FETCHCONTENT_QUIET false)
+
+FetchContent_Declare(
+  ext2fs
+  URL https://github.com/data-accelerator/e2fsprogs/releases/download/latest/libext2fs.tar.gz
+)
+
+FetchContent_GetProperties(ext2fs)
+if (NOT ext2fs_POPULATED)
+  FetchContent_Populate(ext2fs)
+endif()
+
+set(EXT2FS_INCLUDE_DIR ${ext2fs_SOURCE_DIR}/include)
+find_library(EXT2FS_LIBRARY ext2fs HINTS ${ext2fs_SOURCE_DIR}/lib/)

src/extfs/CMakeLists.txt

@@ -1,3 +1,11 @@
+if(CUSTOM_EXT2FS)
+  find_package(ext2fs REQUIRED)
+  include_directories(${EXT2FS_INCLUDE_DIR})
+  set(LIB_EXT2FS ${EXT2FS_LIBRARY})
+else()
+  set(LIB_EXT2FS ext2fs)
+endif()
+
 add_library(extfs_lib
   extfs_io.cpp
   extfs.cpp
@@ -8,7 +16,7 @@ target_include_directories(extfs_lib PUBLIC
 target_link_libraries(extfs_lib
   photon_static
   overlaybd_lib
-  ext2fs
+  ${LIB_EXT2FS}
 )
 
 if(BUILD_TESTING)