ntfs_bdev_read
err = ntfs_bdev_read(sb->s_bdev, al, rl_byte_off,
err = ntfs_bdev_read(sb->s_bdev, (char *)m,
int ntfs_bdev_read(struct block_device *bdev, char *data, loff_t start, size_t size);
if (ntfs_bdev_read(sb->s_bdev, boot_sector, 0, PAGE_SIZE)) {