Re: [PATCH v12 19/41] btrfs: extract page adding function

[Josef Bacik <josef@toxicpanda.com>]

On 1/15/21 1:53 AM, Naohiro Aota wrote:
> This commit extract page adding to bio part from submit_extent_page(). The
> page is added only when bio_flags are the same, contiguous and the added
> page fits in the same stripe as pages in the bio.
> 
> Condition checkings are reordered to allow early return to avoid possibly
> heavy btrfs_bio_fits_in_stripe() calling.
> 
> Reviewed-by: Josef Bacik <josef@toxicpanda.com>
> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
> ---
>   fs/btrfs/extent_io.c | 57 ++++++++++++++++++++++++++++++++------------
>   1 file changed, 42 insertions(+), 15 deletions(-)
> 
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index 129d571a5c1a..96f43b9121d6 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -3061,6 +3061,45 @@ struct bio *btrfs_bio_clone_partial(struct bio *orig, int offset, int size)
>   	return bio;
>   }
>   
> +/**
> + * btrfs_bio_add_page	-	attempt to add a page to bio
> + * @bio:	destination bio
> + * @page:	page to add to the bio
> + * @logical:	offset of the new bio or to check whether we are adding
> + *              a contiguous page to the previous one
> + * @pg_offset:	starting offset in the page
> + * @size:	portion of page that we want to write
> + * @prev_bio_flags:  flags of previous bio to see if we can merge the current one
> + * @bio_flags:	flags of the current bio to see if we can merge them
> + * @return:	true if page was added, false otherwise
> + *
> + * Attempt to add a page to bio considering stripe alignment etc. Return
> + * true if successfully page added. Otherwise, return false.
> + */
> +static bool btrfs_bio_add_page(struct bio *bio, struct page *page, u64 logical,
> +			       unsigned int size, unsigned int pg_offset,
> +			       unsigned long prev_bio_flags,
> +			       unsigned long bio_flags)
> +{
> +	sector_t sector = logical >> SECTOR_SHIFT;
> +	bool contig;
> +
> +	if (prev_bio_flags != bio_flags)
> +		return false;
> +
> +	if (prev_bio_flags & EXTENT_BIO_COMPRESSED)
> +		contig = bio->bi_iter.bi_sector == sector;
> +	else
> +		contig = bio_end_sector(bio) == sector;
> +	if (!contig)
> +		return false;
> +
> +	if (btrfs_bio_fits_in_stripe(page, size, bio, bio_flags))
> +		return false;
> +
> +	return bio_add_page(bio, page, size, pg_offset) == size;
> +}
> +
>   /*
>    * @opf:	bio REQ_OP_* and REQ_* flags as one value
>    * @wbc:	optional writeback control for io accounting
> @@ -3089,27 +3128,15 @@ static int submit_extent_page(unsigned int opf,
>   	int ret = 0;
>   	struct bio *bio;
>   	size_t io_size = min_t(size_t, size, PAGE_SIZE);
> -	sector_t sector = offset >> 9;

offset has been renamed to disk_bytenr in misc-next, you'll need to refresh 
these patches against misc-next as this doesn't apply cleanly.  Thanks,

Josef