diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c
index 41652dcd16f4..4c7089b1681b 100644
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -2243,12 +2243,8 @@ static inline int btrfs_calc_avail_data_space(struct btrfs_fs_info *fs_info,
 
 	if (type & BTRFS_BLOCK_GROUP_RAID0)
 		num_stripes = nr_devices;
-	else if (type & BTRFS_BLOCK_GROUP_RAID1)
-		num_stripes = 2;
-	else if (type & BTRFS_BLOCK_GROUP_RAID1C3)
-		num_stripes = 3;
-	else if (type & BTRFS_BLOCK_GROUP_RAID1C4)
-		num_stripes = 4;
+	else if (type & BTRFS_BLOCK_GROUP_RAID1_MASK)
+		num_stripes = rattr->ncopies;
 	else if (type & BTRFS_BLOCK_GROUP_RAID10)
 		num_stripes = 4;