md: Fix dev_sectors on takeover from raid0 to raid4/5

A raid0 array doesn't set 'dev_sectors' as each device might
contribute a different number of sectors.
So when converting to a RAID4 or RAID5 we need to set dev_sectors
as they need the number.
We have already verified that in fact all devices do contribute
the same number of sectors, so use that number.

Signed-off-by: NeilBrown <neilb@suse.de>

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 179bdfc..fd50011 100644 (file)
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5678,6 +5678,7 @@ static void raid5_quiesce(mddev_t *mddev, int state)
 static void *raid45_takeover_raid0(mddev_t *mddev, int level)
 {
        struct raid0_private_data *raid0_priv = mddev->private;
+       unsigned long long sectors;
 
        /* for raid0 takeover only one zone is supported */
        if (raid0_priv->nr_strip_zones > 1) {
@@ -5686,6 +5687,9 @@ static void *raid45_takeover_raid0(mddev_t *mddev, int level)
                return ERR_PTR(-EINVAL);
        }
 
+       sectors = raid0_priv->strip_zone[0].zone_end;
+       sector_div(sectors, raid0_priv->strip_zone[0].nb_dev);
+       mddev->dev_sectors = sectors;
        mddev->new_level = level;
        mddev->new_layout = ALGORITHM_PARITY_N;
        mddev->new_chunk_sectors = mddev->chunk_sectors;