diff --git a/libguestfs.spec b/libguestfs.spec
index 8d8a624..07dd66a 100644
--- a/libguestfs.spec
+++ b/libguestfs.spec
@@ -362,6 +362,25 @@ test -n "$ext_cmds"
 #
 > ext_cmds.txt
 > missing_cmds.txt
+# guestfs may call mkfs, but it cant tell in advance which filesystems
+# it must support. Collect a manual list of possible filesystems so that
+# the commands get included in the initrd.
+for fs in \
+	ext2 \
+	ext3 \
+	ext4 \
+	ntfs \
+	reiserfs \
+	jfs \
+	gfs \
+	gfs2 \
+	vfat \
+	msdos \
+	ufs \
+; do
+	echo mkfs.$fs
+done >> ext_cmds.txt
+#
 for cmd in ls $ext_cmds
 do
 	if test -n "` PATH=$PATH:/sbin:/usr/sbin type -p $cmd `"