> +static ssize_t btrfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
> +{
> + ssize_t ret = 0;
> + if (iocb->ki_flags & IOCB_DIRECT)
Missing empty line after the declaration.
> +ssize_t btrfs_dio_iomap_read(struct kiocb *iocb, struct iov_iter *to)
The iomap in the name doesn't seem to add much. In fact I'm not even
sure the function adds all that much, I would have just open coded it.
