reproduce (this is a W=1 build):
        # https://github.com/koverstreet/bcachefs/commit/7f0ae9ab2f5f2ea12951f1d5ff04ff35bbee8d3f
        git remote add koverstreet-bcachefs https://github.com/koverstreet/bcachefs
        git fetch --no-tags koverstreet-bcachefs inode_hash_find_debug
        git checkout 7f0ae9ab2f5f2ea12951f1d5ff04ff35bbee8d3f
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash fs/bcachefs/