On Fri, 14 Jan 2011 14:00:08 +0100 Adam Kwolek <adam.kwolek@xxxxxxxxx> wrote:
> When we performing expansion on degraded array (takeovered raid0),
> and we are adding i.e. 2 disks, one disk is added only.
>
> this is due to fact that parity (missing) disk is moved to the end
> and added disk index is smaller than starting disk number in array.
>
> To resolve this situation array degradation should be used for adding
> disk(s) on reshape start.
>
> Signed-off-by: Adam Kwolek <adam.kwolek@xxxxxxxxx>
> ---
>
> drivers/md/raid5.c | 6 ++++--
> 1 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> index 59c4150..3b9da76 100644
> --- a/drivers/md/raid5.c
> +++ b/drivers/md/raid5.c
> @@ -5528,7 +5528,8 @@ static int raid5_start_reshape(mddev_t *mddev)
> return -ENOSPC;
>
> list_for_each_entry(rdev, &mddev->disks, same_set)
> - if ((rdev->raid_disk < 0 || rdev->raid_disk >= conf->raid_disks)
> + if ((rdev->raid_disk < 0 ||
> + rdev->raid_disk >= (conf->raid_disks - mddev->degraded))
> && !test_bit(Faulty, &rdev->flags))
> spares++;
>
> @@ -5589,7 +5590,8 @@ static int raid5_start_reshape(mddev_t *mddev)
> /* Failure here is OK */;
> } else
> break;
> - } else if (rdev->raid_disk >= conf->previous_raid_disks
> + } else if (rdev->raid_disk >= (conf->previous_raid_disks
> + - mddev->degraded)
> && !test_bit(Faulty, &rdev->flags)) {
> /* This is a spare that was manually added */
> if (raid5_add_disk(mddev, rdev) == 0) {
I see the problem you are trying to fix, but I think the fix is wrong.
The range check is correct, but the test for Faulty isn't quite right.
I think we need to check for In_sync and not Faulty, or something like that.
I work something out.
Thanks,
NeilBrown
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