reproduce (this is a W=1 build):
        # https://github.com/kdave/btrfs-devel/commit/c9a96c234f18aeb5d5760a8e90a20971ec75be41
        git remote add kdave-btrfs-devel https://github.com/kdave/btrfs-devel.git
        git fetch --no-tags kdave-btrfs-devel fix-6.7-device-scanning
        git checkout c9a96c234f18aeb5d5760a8e90a20971ec75be41
        # 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/btrfs/