Re: [PATCH 1/3] xfs: handle ERR_PTR return from bio_split in xfs_buf_submit_bio

[Donald Douwsma <ddouwsma@redhat.com>]

On 18/4/26 19:27, Long Li wrote:
> bio_split() now returns ERR_PTR() on failure rather than NULL.
> xfs_buf_submit_bio() currently ignores the return value and
> dereferences it unconditionally, which will crash on error.
> 
> Add an IS_ERR() check after bio_split(). On failure, flush the plug
> to dispatch any already-chained split bios, then call bio_endio()
> with BLK_STS_IOERR on the parent bio. Because bio_chain() increments
> the parent's bi_remaining for each chained child, the end_io callback
> fires only after all children complete, propagating the error back to
> xfs_buf through the normal path.
> 
> Fixes: e546fe1da9bd ("block: Rework bio_split() return value")

This looks like it could cause problems further back?
Perhaps 
    fac69ec8cd74 xfs: simplify buffer I/O submission


Don


> Signed-off-by: Long Li <leo.lilong@huawei.com>
> ---
>  fs/xfs/xfs_buf.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
> index 580d40a5ee57..fda215dd00df 100644
> --- a/fs/xfs/xfs_buf.c
> +++ b/fs/xfs/xfs_buf.c
> @@ -1268,6 +1268,12 @@ xfs_buf_submit_bio(
>  
>  		split = bio_split(bio, bp->b_maps[map].bm_len, GFP_NOFS,
>  				&fs_bio_set);
> +		if (IS_ERR(split)) {
> +			blk_finish_plug(&plug);
> +			bio->bi_status = BLK_STS_IOERR;
> +			bio_endio(bio);
> +			return;
> +		}
>  		split->bi_iter.bi_sector = bp->b_maps[map].bm_bn;
>  		bio_chain(split, bio);
>  		submit_bio(split);