[Ocfs2-devel] [PATCH] ocfs2/o2hb: check len for bio_add_page() to avoid submitting incorrect bio

[Joseph Qi]

On 18/3/28 11:50, piaojun wrote:
> We need check len for bio_add_page() to make sure the bio has been set up
> correctly, otherwise we may submit incorrect data to device.
> 
> Signed-off-by: Jun Piao <piaojun at huawei.com>
> Reviewed-by: Yiwen Jiang <jiangyiwen at huawei.com>
> ---
>  fs/ocfs2/cluster/heartbeat.c | 11 ++++++++++-
>  1 file changed, 10 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
> index ea8c551..43ad79f 100644
> --- a/fs/ocfs2/cluster/heartbeat.c
> +++ b/fs/ocfs2/cluster/heartbeat.c
> @@ -570,7 +570,16 @@ static struct bio *o2hb_setup_one_bio(struct o2hb_region *reg,
>  		     current_page, vec_len, vec_start);
> 
>  		len = bio_add_page(bio, page, vec_len, vec_start);
> -		if (len != vec_len) break;
> +		if (len != vec_len) {
> +			mlog(ML_ERROR, "Adding page[%d] to bio failed, "
> +			     "page %p, len %d, vec_len %u, vec_start %u, "
> +			     "bi_sector %llu\n", current_page, page, len,
> +			     vec_len, vec_start,
> +			     (unsigned long long)bio->bi_iter.bi_sector);
> +			bio_put(bio);
> +			bio = ERR_PTR(-EFAULT);

IMO, EFAULT is not an appropriate error code here.
If __bio_add_page returns 0, some are caused by bio checking failed.
Also I've noticed that several other callers just use ENOMEM, so I think
EINVAL or ENOMEM may be better.

Thanks,
Joseph

> +			return bio;
> +		}
> 
>  		cs += vec_len / (PAGE_SIZE/spp);
>  		vec_start = 0;
>