static int
btrfs_get_bdev_and_sb(const char *device_path, blk_mode_t flags, void *holder,
		      int flush, struct bdev_handle **bdev_handle,
		      struct btrfs_super_block **disk_super)
static int
btrfs_get_bdev_and_sb(const char *device_path, blk_mode_t flags, void *holder,
		      int flush, struct file **bdev_file,
		      struct btrfs_super_block **disk_super)