root_add_used    3411 fs/btrfs/ctree.c 	root_add_used(root, fs_info->nodesize);
root_add_used    3541 fs/btrfs/ctree.c 	root_add_used(root, fs_info->nodesize);
root_add_used    4322 fs/btrfs/ctree.c 	root_add_used(root, fs_info->nodesize);