Re: [PATCH] md/raid5: cast chunk_sectors to sector_t value

[Song Liu <song@kernel.org>]

On Tue, Dec 15, 2020 at 5:26 PM Guoqing Jiang
<guoqing.jiang@cloud.ionos.com> wrote:
>
> Currently, raid5 calculates dev_sectors from chunk_sectors without
> proper cast, which is problematic.
>
> Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
> ---
> I think the recently report about raid5 issue could be related with
> the setting of dev_sectors.
>
> Could someone test it with a large raid5 array? Thanks.

Yes, this was the exact problem. I will apply this to md-next. (probably
after the merge window).

Thanks,
Song

>
>  drivers/md/raid5.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index 3934347..ca0b29a 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -7662,7 +7662,7 @@ static int raid5_run(struct mddev *mddev)
>         }
>
>         /* device size must be a multiple of chunk size */
> -       mddev->dev_sectors &= ~(mddev->chunk_sectors - 1);
> +       mddev->dev_sectors &= ~((sector_t)mddev->chunk_sectors - 1);
>         mddev->resync_max_sectors = mddev->dev_sectors;
>
>         if (mddev->degraded > dirty_parity_disks &&
> --
> 2.7.4
>