Re: [PATCH v1 6/7] xfs: Rewrite retried read

Dave Chinner
2018-11-28T16:20:48Z

On Tue, Nov 27, 2018 at 08:49:50PM -0700, Allison Henderson wrote:
> If we had to try more than one mirror to get a successful
> read, then write that buffer back to correct the bad mirro
>
> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
> ---
> fs/xfs/xfs_buf.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
> index f102d01..81f6491 100644
> --- a/fs/xfs/xfs_buf.c
> +++ b/fs/xfs/xfs_buf.c
> @@ -847,6 +847,14 @@ xfs_buf_read_map(
>
> }
> retry_done:
> +
> + /*
> + * if we had to try more than one mirror to sucessfully read
> + * the buffer, write the buffer back
> + */
> + if (!bp->b_error && i > 0)
> + xfs_bwrite(bp);
> +

This can go in the case statement on retry and then you don't need
to check for i > 0 or, well, bp->b_error. i.e.

swtich (bp->b_error) {
case -EBADCRC:
case -EIO:
case -EFSCORRUPTED:
/* try again from different copy */
continue;
0:
/* good copy, rewrite it to repair bad copy */
xfs_bwrite(bp);
/* fallthrough */
default:
return bp;
}

Cheers,

Dave.
--
Dave Chinner
david@fromorbit.com