From: NeilBrown <neilb@suse.de>
Date: Wed, 9 Mar 2011 07:30:03 +0000 (+1100)
Subject: Grow: allow a RAID1 to be reshaped directly to 3-drive RAID5
X-Git-Tag: mdadm-3.2.1~82
X-Git-Url: http://git.ipfire.org/?p=thirdparty%2Fmdadm.git;a=commitdiff_plain;h=5652f2d9cec5f03a698a86ef31700277e8699dc8

Grow: allow a RAID1 to be reshaped directly to 3-drive RAID5

Self-tests require this but code didn't allow it any more.

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

diff --git a/Grow.c b/Grow.c
index 88c8ad75..387bdbd5 100644
--- a/Grow.c
+++ b/Grow.c
@@ -952,13 +952,17 @@ char *analyse_change(struct mdinfo *info, struct reshape *re)
 		}
 		if (info->array.raid_disks == 2 &&
 		    info->new_level == 5) {
-			if (info->delta_disks != UnSet &&
-			    info->delta_disks != 0)
-				return "Cannot change number of disks "
-					"with RAID1->RAID5 conversion";
+
 			re->level = 5;
 			re->before.data_disks = 1;
-			re->after.data_disks = 1;
+			if (info->delta_disks != UnSet &&
+			    info->delta_disks != 0)
+				re->after.data_disks = 1 + info->delta_disks;
+			else
+				re->after.data_disks = 1;
+			if (re->after.data_disks < 1)
+				return "Number of disks too small for RAID5";
+
 			re->before.layout = ALGORITHM_LEFT_SYMMETRIC;
 			info->array.chunk_size = 65536;
 			break;