Re: [PATCH] btrfs: Kill some bi_idx references

[Stefan Behrens <sbehrens@giantdisaster.de>]

On Tue, 11 Sep 2012 14:31:14 -0700, Kent Overstreet wrote:
> For immutable bio vecs, I've been auditing and removing bi_idx
> references. These were harmless, but removing them will make auditing
> easier.
> 
> scrub_bio_end_io_worker() was open coding a bio_reset() - but this
> doesn't appear to have been needed for anything as right after it does a
> bio_put(), and perusing the code it doesn't appear anything else was
> holding a reference to the bio.
> 
> The other use end_bio_extent_readpage() was just for a pr_debug() -
> changed it to something that might be a bit more useful.
> 
> Signed-off-by: Kent Overstreet <koverstreet@google.com>
> CC: Chris Mason <chris.mason@fusionio.com>
> CC: Stefan Behrens <sbehrens@giantdisaster.de>
> ---
>  fs/btrfs/extent_io.c |  4 ++--
>  fs/btrfs/scrub.c     | 15 ---------------
>  2 files changed, 2 insertions(+), 17 deletions(-)
> 
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index 4c87847..8d7fb96 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -2298,8 +2298,8 @@ static void end_bio_extent_readpage(struct bio *bio, int err)
>  		struct extent_state *cached = NULL;
>  		struct extent_state *state;
>  
> -		pr_debug("end_bio_extent_readpage: bi_vcnt=%d, idx=%d, err=%d, "
> -			 "mirror=%ld\n", bio->bi_vcnt, bio->bi_idx, err,
> +		pr_debug("end_bio_extent_readpage: bi_sector=%llu, err=%d, "
> +			 "mirror=%ld\n", (u64)bio->bi_sector, err,
>  			 (long int)bio->bi_bdev);
>  		tree = &BTRFS_I(page->mapping->host)->io_tree;
>  
> diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
> index b223620..2683ea7 100644
> --- a/fs/btrfs/scrub.c
> +++ b/fs/btrfs/scrub.c
> @@ -1666,21 +1666,6 @@ static void scrub_bio_end_io_worker(struct btrfs_work *work)
>  		scrub_block_put(sblock);
>  	}
>  
> -	if (sbio->err) {
> -		/* what is this good for??? */
> -		sbio->bio->bi_flags &= ~(BIO_POOL_MASK - 1);
> -		sbio->bio->bi_flags |= 1 << BIO_UPTODATE;
> -		sbio->bio->bi_phys_segments = 0;
> -		sbio->bio->bi_idx = 0;
> -
> -		for (i = 0; i < sbio->page_count; i++) {
> -			struct bio_vec *bi;
> -			bi = &sbio->bio->bi_io_vec[i];
> -			bi->bv_offset = 0;
> -			bi->bv_len = PAGE_SIZE;
> -		}
> -	}
> -
>  	bio_put(sbio->bio);
>  	sbio->bio = NULL;
>  	spin_lock(&sdev->list_lock);
> 

Yes, it is correct to remove these lines in the btrfs scrub code. They
are a relict from the past.