file_to_blk_mode
blk_mode_t file_to_blk_mode(struct file *file);
mode = file_to_blk_mode(filp);
error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
blk_mode_t mode = file_to_blk_mode(file);
blk_mode_t mode = file_to_blk_mode(file);
if (!(file_to_blk_mode(cmd->file) & BLK_OPEN_WRITE))