md: add takeover support for raid4 -> raid5 conversion.

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

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 8a5e14e4a851..95953273c4d9 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4967,6 +4967,11 @@ static void *raid5_takeover(mddev_t *mddev)
 
         if (mddev->level == 1)
                 return raid5_takeover_raid1(mddev);
+        if (mddev->level == 4) {
+                mddev->new_layout = ALGORITHM_PARITY_N;
+                mddev->new_level = 5;
+                return setup_conf(mddev);
+        }
 
         return ERR_PTR(-EINVAL);
 }