reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git/commit/?id=a13409e8c652b4fce3d5741a68a85d4427a8d569
        git remote add djwong-xfs https://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux.git
        git fetch --no-tags djwong-xfs xfile-page-caching
        git checkout a13409e8c652b4fce3d5741a68a85d4427a8d569
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=x86_64 olddefconfig
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash fs/xfs/