diff --git a/fs/ocfs2/slot_map.c b/fs/ocfs2/slot_map.c
index e544c704b583..79f9d1753bc1 100644
--- a/fs/ocfs2/slot_map.c
+++ b/fs/ocfs2/slot_map.c
@@ -193,6 +193,17 @@ static int ocfs2_update_disk_slot(struct ocfs2_super *osb,
 	else
 		ocfs2_update_disk_slot_old(si, slot_num, &bh);
 	spin_unlock(&osb->osb_lock);
+	if (bh->b_blocknr < OCFS2_SUPER_BLOCK_BLKNO) {
+		status = ocfs2_error(osb->sb,
+				     "Invalid Slot Map Buffer Head "
+				     "Block Number : %llu, Should be >= %d",
+				     le16_to_cpu(bh->b_blocknr),
+				     le16_to_cpu((int)OCFS2_SUPER_BLOCK_BLKNO));
+		if(!status) {
+			return -EIO;
+		}
+		return status;
+	}
 
 	status = ocfs2_write_block(osb, bh, INODE_CACHE(si->si_inode));
 	if (status < 0)