mdadm/bitmap: locate bitmap calcuate bitmap position wrongly

Now it only adds bitmap offset based on cluster nodes. It's not right. It needs to
add per node bitmap space to find next node bitmap position.

Signed-off-by: Xiao Ni <xni@redhat.com>
Signed-off-by: Jes Sorensen <jsorensen@fb.com>

1 files changed, 9 insertions, 3 deletions

diff --git a/super1.c b/super1.c
index 8b0d6ff3..b5b379b3 100644
--- a/super1.c
+++ b/super1.c
@@ -2582,8 +2582,9 @@ add_internal_bitmap1(struct supertype *st,
 
 static int locate_bitmap1(struct supertype *st, int fd, int node_num)
 {
-	unsigned long long offset;
+	unsigned long long offset, bm_sectors_per_node;
 	struct mdp_superblock_1 *sb;
+	bitmap_super_t *bms;
 	int mustfree = 0;
 	int ret;
 
@@ -2598,8 +2599,13 @@ static int locate_bitmap1(struct supertype *st, int fd, int node_num)
 		ret = 0;
 	else
 		ret = -1;
-	offset = __le64_to_cpu(sb->super_offset);
-	offset += (int32_t) __le32_to_cpu(sb->bitmap_offset) * (node_num + 1);
+
+	offset = __le64_to_cpu(sb->super_offset) + __le32_to_cpu(sb->bitmap_offset);
+	if (node_num) {
+		bms = (bitmap_super_t*)(((char*)sb)+MAX_SB_SIZE);
+		bm_sectors_per_node = calc_bitmap_size(bms, 4096) >> 9;
+		offset += bm_sectors_per_node * node_num;
+	}
 	if (mustfree)
 		free(sb);
 	lseek64(fd, offset<<9, 0);