Re: [PATCH 2/2] btrfs: refactor btrfs_dio_submit_io() for less nesting and indentation

[Qu Wenruo <quwenruo.btrfs@gmx.com>]

在 2024/5/14 23:53, fdmanana@kernel.org 写道:
> From: Filipe Manana <fdmanana@suse.com>
>
> Refactor btrfs_dio_submit_io() to avoid so much nesting and the need to
> split long lines, making it a bit easier to read.
>
> Signed-off-by: Filipe Manana <fdmanana@suse.com>

Reviewed-by: Qu Wenruo <wqu@suse.com>

Thanks,
Qu
> ---
>   fs/btrfs/inode.c | 52 +++++++++++++++++++++++-------------------------
>   1 file changed, 25 insertions(+), 27 deletions(-)
>
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index f04852e44123..c7f0239c3b68 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -7869,6 +7869,8 @@ static void btrfs_dio_submit_io(const struct iomap_iter *iter, struct bio *bio,
>   	struct btrfs_dio_private *dip =
>   		container_of(bbio, struct btrfs_dio_private, bbio);
>   	struct btrfs_dio_data *dio_data = iter->private;
> +	struct btrfs_ordered_extent *oe = dio_data->ordered;
> +	int ret;
>
>   	btrfs_bio_init(bbio, BTRFS_I(iter->inode)->root->fs_info,
>   		       btrfs_dio_end_io, bio->bi_private);
> @@ -7880,6 +7882,8 @@ static void btrfs_dio_submit_io(const struct iomap_iter *iter, struct bio *bio,
>
>   	dio_data->submitted += bio->bi_iter.bi_size;
>
> +	if (!(iter->flags & IOMAP_WRITE))
> +		goto submit_bio;
>   	/*
>   	 * Check if we are doing a partial write.  If we are, we need to split
>   	 * the ordered extent to match the submitted bio.  Hang on to the
> @@ -7887,37 +7891,31 @@ static void btrfs_dio_submit_io(const struct iomap_iter *iter, struct bio *bio,
>   	 * cancelled in iomap_end to avoid a deadlock wherein faulting the
>   	 * remaining pages is blocked on the outstanding ordered extent.
>   	 */
> -	if (iter->flags & IOMAP_WRITE) {
> -		struct btrfs_ordered_extent *oe = dio_data->ordered;
> -		int ret;
> -
> -		ret = btrfs_extract_ordered_extent(bbio, oe);
> -		if (ret) {
> -			/*
> -			 * If this is a COW write it means we created new extent
> -			 * maps for the range and they point to an unwritten
> -			 * location since we got an error and we don't submit
> -			 * a bio. We must drop any extent maps within the range,
> -			 * otherwise a fast fsync would log them and after a
> -			 * crash and log replay we would have file extent items
> -			 * that point to unwritten locations (garbage).
> -			 */
> -			if (!test_bit(BTRFS_ORDERED_NOCOW, &oe->flags)) {
> -				const u64 start = oe->file_offset;
> -				const u64 end = start + oe->num_bytes - 1;
> +	ret = btrfs_extract_ordered_extent(bbio, oe);
> +	if (!ret)
> +		goto submit_bio;
>
> -				btrfs_drop_extent_map_range(bbio->inode, start, end, false);
> -			}
> +	/*
> +	 * If this is a COW write it means we created new extent maps for the
> +	 * range and they point to an unwritten location since we got an error
> +	 * and we don't submit a bio. We must drop any extent maps within the
> +	 * range, otherwise a fast fsync would log them and after a crash and
> +	 * log replay we would have file extent items that point to unwritten
> +	 * locations (garbage).
> +	 */
> +	if (!test_bit(BTRFS_ORDERED_NOCOW, &oe->flags)) {
> +		const u64 start = oe->file_offset;
> +		const u64 end = start + oe->num_bytes - 1;
>
> -			btrfs_finish_ordered_extent(oe, NULL,
> -						    file_offset, dip->bytes,
> -						    !ret);
> -			bio->bi_status = errno_to_blk_status(ret);
> -			iomap_dio_bio_end_io(bio);
> -			return;
> -		}
> +		btrfs_drop_extent_map_range(bbio->inode, start, end, false);
>   	}
>
> +	btrfs_finish_ordered_extent(oe, NULL, file_offset, dip->bytes, false);
> +	bio->bi_status = errno_to_blk_status(ret);
> +	iomap_dio_bio_end_io(bio);
> +	return;
> +
> +submit_bio:
>   	btrfs_submit_bio(bbio, 0);
>   }
>