Re: [PATCH] btrfs: not a disk error if the bio_add_page fails

[Filipe Manana <fdmanana@gmail.com>]

On Wed, Jan 3, 2018 at 8:07 AM, Anand Jain <anand.jain@oracle.com> wrote:
> bio_add_page() can fail for logical reasons as from the bio_add_page()
> comments:- 'This will only fail if either
> bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.' Don't inc the
> write error statistics for this. And set -EINVAL instead of -EIO.
>
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> ---
>  fs/btrfs/scrub.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c
> index d766c73eb29a..8c1508a41f90 100644
> --- a/fs/btrfs/scrub.c
> +++ b/fs/btrfs/scrub.c
> @@ -4618,15 +4618,15 @@ static int write_page_nocow(struct scrub_ctx *sctx,
>         bio->bi_opf = REQ_OP_WRITE | REQ_SYNC;
>         ret = bio_add_page(bio, page, PAGE_SIZE, 0);
>         if (ret != PAGE_SIZE) {
> -leave_with_eio:
>                 bio_put(bio);
> +               return -EINVAL;
> +       }
> +
> +       if (btrfsic_submit_bio_wait(bio)) {
>                 btrfs_dev_stat_inc_and_print(dev, BTRFS_DEV_STAT_WRITE_ERRS);
>                 return -EIO;
>         }

You are now introducing a leak of the bio. Missing bio_put(bio) before
returning.

>
> -       if (btrfsic_submit_bio_wait(bio))
> -               goto leave_with_eio;
> -
>         bio_put(bio);
>         return 0;
>  }
> --
> 2.15.0
>
> --
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-- 
Filipe David Manana,

“Whether you think you can, or you think you can't — you're right.”