From: NeilBrown <neilb@suse.de>
Date: Tue, 31 Mar 2009 03:57:20 +0000 (+1100)
Subject: md: add takeover support for converting raid6 back into raid5
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=fc9739c6d626ee79a148ec367d143b0601299a9d;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

md: add takeover support for converting raid6 back into raid5

If a raid6 is still in the layout that comes from converting raid5
into a raid6. this will allow us to convert it back again.

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

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 95953273c4d9..70b50af2bcd7 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -4912,6 +4912,39 @@ static void *raid5_takeover_raid1(mddev_t *mddev)
 	return setup_conf(mddev);
 }
 
+static void *raid5_takeover_raid6(mddev_t *mddev)
+{
+	int new_layout;
+
+	switch (mddev->layout) {
+	case ALGORITHM_LEFT_ASYMMETRIC_6:
+		new_layout = ALGORITHM_LEFT_ASYMMETRIC;
+		break;
+	case ALGORITHM_RIGHT_ASYMMETRIC_6:
+		new_layout = ALGORITHM_RIGHT_ASYMMETRIC;
+		break;
+	case ALGORITHM_LEFT_SYMMETRIC_6:
+		new_layout = ALGORITHM_LEFT_SYMMETRIC;
+		break;
+	case ALGORITHM_RIGHT_SYMMETRIC_6:
+		new_layout = ALGORITHM_RIGHT_SYMMETRIC;
+		break;
+	case ALGORITHM_PARITY_0_6:
+		new_layout = ALGORITHM_PARITY_0;
+		break;
+	case ALGORITHM_PARITY_N:
+		new_layout = ALGORITHM_PARITY_N;
+		break;
+	default:
+		return ERR_PTR(-EINVAL);
+	}
+	mddev->new_level = 5;
+	mddev->new_layout = new_layout;
+	mddev->delta_disks = -1;
+	mddev->raid_disks -= 1;
+	return setup_conf(mddev);
+}
+
 
 static int raid5_reconfig(mddev_t *mddev, int new_layout, int new_chunk)
 {
@@ -4972,6 +5005,8 @@ static void *raid5_takeover(mddev_t *mddev)
 		mddev->new_level = 5;
 		return setup_conf(mddev);
 	}
+	if (mddev->level == 6)
+		return raid5_takeover_raid6(mddev);
 
 	return ERR_PTR(-EINVAL);
 }