On 5/19/23 18:35, Christoph Hellwig wrote:
> Add a helper dealing with handling the syncing of a buffered write fallback
> for direct I/O.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Looks OK. One comment below.
Reviewed-by: Damien Le Moal <dlemoal@xxxxxxxxxx>
> + /*
> + * We need to ensure that the page cache pages are written to disk and
> + * invalidated to preserve the expected O_DIRECT semantics.
> + */
> + end = pos + buffered_written - 1;
> + err = filemap_write_and_wait_range(mapping, pos, end);
> + if (err < 0) {
> + /*
> + * We don't know how much we wrote, so just return the number of
> + * bytes which were direct-written
> + */
> + return err;
> + }
> + invalidate_mapping_pages(mapping, pos >> PAGE_SHIFT, end >> PAGE_SHIFT);
> + return direct_written + buffered_written;
Why not adding here something like:
if (buffered_written != iov_iter_count(from))
return -EIO;
return direct_written + buffered_written;
to have the same semantic as plain DIO ?
--
Damien Le Moal
Western Digital Research
