Re: [PATCH 1/1] md: Do only necessary operations when adding device to RO array

From: NeilBrown
Date: Sun Jun 01 2014 - 22:34:25 EST


On Fri, 30 May 2014 13:17:14 +0000 "Baldysiak, Pawel"
<pawel.baldysiak@xxxxxxxxx> wrote:

> Commit 8313b8e57f55b15e5b7f7fc5d1630bbf686a9a97 changed
> way of adding device to read-only array. Used routine
> md_reap_sync_thread() which also trigger finish_reshape(),
> can break reshape process, if it was restarted.

Exactly how can it break?

This is probably fixed by a couple of patches in my for-next branch which I
will be sending to Linus shortly.

NeilBrown


> This part of function should do only necessary operations, that is:
> 1) call ->spare_active
> 2) clear saved_raid_disk if array is no longer degraded
>
> Signed-off-by: Pawel Baldysiak <pawel.baldysiak@xxxxxxxxx>
> Reviewed-by: Artur Paszkiewicz <artur.paszkiewicz@xxxxxxxxx>
>
> ---
> drivers/md/md.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/md/md.c b/drivers/md/md.c
> index 237b7e0..cf073de2 100644
> --- a/drivers/md/md.c
> +++ b/drivers/md/md.c
> @@ -7820,11 +7820,13 @@ void md_check_recovery(struct mddev *mddev)
> * As we only add devices that are already in-sync,
> * we can activate the spares immediately.
> */
> + struct md_rdev *rdev;
> remove_and_add_spares(mddev, NULL);
> - /* There is no thread, but we need to call
> - * ->spare_active and clear saved_raid_disk
> - */
> - md_reap_sync_thread(mddev);
> + mddev->pers->spare_active(mddev);
> + rdev_for_each(rdev, mddev)
> + if (!mddev->degraded ||
> + test_bit(In_sync, &rdev->flags))
> + rdev->saved_raid_disk = -1;
> clear_bit(MD_RECOVERY_NEEDED, &mddev->recovery);
> goto unlock;
> }
> --
> 1.9.0

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