Only try to use btrfs snapshots if chroots are on a btrfs partition

archbuild.in

@@ -58,7 +58,9 @@ if ${clean_first} || [[ ! -d "${chroots}/${repo}-${arch}" ]]; then
 			stat_done
 		fi
 
-		{ type -P btrfs && btrfs subvolume delete "${copy}"; } &>/dev/null
+		if [[ "$(stat -f -c %T "${copy}")" == btrfs ]]; then
+			{ type -P btrfs && btrfs subvolume delete "${copy}"; } &>/dev/null
+		fi
 		rm -rf --one-file-system "${copy}"
 	done
 	exec 9>&-

mkarchroot.in

@@ -160,8 +160,10 @@ else
 		mkdir -p "${working_dir}"
 	fi
 
-	if { type -P btrfs && btrfs subvolume create "${working_dir}"; } &>/dev/null; then
-		chmod 0755 "${working_dir}"
+	if [[ "$(stat -f -c %T "${working_dir}")" == btrfs ]]; then
+		if { type -P btrfs && btrfs subvolume create "${working_dir}"; } &>/dev/null; then
+			chmod 0755 "${working_dir}"
+		fi
 	fi
 
 	chroot_lock