Examine: fix array size calculation for RAID10.

RAID10 arrays with an odd number of devices had the arraysize
reported wrongly by --examine due to a rounding error.

Reported-by: Chris Francy <zoredache@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>

2 files changed, 17 insertions, 11 deletions

diff --git a/super0.c b/super0.c
index eca40d28..13757998 100644
--- a/super0.c
+++ b/super0.c
@@ -114,7 +114,7 @@ static void examine_super0(struct supertype *st, char *homehost)
 	c=map_num(pers, sb->level);
 	printf("     Raid Level : %s\n", c?c:"-unknown-");
 	if ((int)sb->level > 0) {
-		int ddsks=0;
+		int ddsks = 0, ddsks_denom = 1;
 		printf("  Used Dev Size : %d%s\n", sb->size,
 		       human_size((long long)sb->size<<10));
 		switch(sb->level) {
@@ -122,11 +122,15 @@ static void examine_super0(struct supertype *st, char *homehost)
 		case 4:
 		case 5: ddsks = sb->raid_disks-1; break;
 		case 6: ddsks = sb->raid_disks-2; break;
-		case 10: ddsks = sb->raid_disks / (sb->layout&255) / ((sb->layout>>8)&255);
+		case 10: ddsks = sb->raid_disks;
+			ddsks_denom =  (sb->layout&255) * ((sb->layout>>8)&255);
+		}
+		if (ddsks) {
+			long long asize = sb->size;
+			asize = (asize << 10) * ddsks / ddsks_denom;
+			printf("     Array Size : %llu%s\n",
+			       asize >> 10,  human_size(asize));
 		}
-		if (ddsks)
-			printf("     Array Size : %llu%s\n", (unsigned long long)ddsks * sb->size,
-			       human_size(ddsks*(long long)sb->size<<10));
 	}
 	printf("   Raid Devices : %d\n", sb->raid_disks);
 	printf("  Total Devices : %d\n", sb->nr_disks);
diff --git a/super1.c b/super1.c
index 0a3b6d0e..20f4c866 100644
--- a/super1.c
+++ b/super1.c
@@ -278,7 +278,7 @@ static void examine_super1(struct supertype *st, char *homehost)
 	       (unsigned long long)__le64_to_cpu(sb->data_size),
 	       human_size(__le64_to_cpu(sb->data_size)<<9));
 	if (__le32_to_cpu(sb->level) > 0) {
-		int ddsks=0;
+		int ddsks = 0, ddsks_denom = 1;
 		switch(__le32_to_cpu(sb->level)) {
 		case 1: ddsks=1;break;
 		case 4:
@@ -286,13 +286,15 @@ static void examine_super1(struct supertype *st, char *homehost)
 		case 6: ddsks = __le32_to_cpu(sb->raid_disks)-2; break;
 		case 10:
 			layout = __le32_to_cpu(sb->layout);
-			ddsks = __le32_to_cpu(sb->raid_disks)
-				 / (layout&255) / ((layout>>8)&255);
+			ddsks = __le32_to_cpu(sb->raid_disks);
+			ddsks_denom = (layout&255) * ((layout>>8)&255);
 		}
-		if (ddsks)
+		if (ddsks) {
+			long long asize = __le64_to_cpu(sb->size);
+			asize = (asize << 9) * ddsks / ddsks_denom;
 			printf("     Array Size : %llu%s\n",
-			       ddsks*(unsigned long long)__le64_to_cpu(sb->size),
-			       human_size(ddsks*__le64_to_cpu(sb->size)<<9));
+			       asize >> 10,  human_size(asize));
+		}
 		if (sb->size != sb->data_size)
 			printf("  Used Dev Size : %llu%s\n",
 			       (unsigned long long)__le64_to_cpu(sb->size),