diff -ru udev-182.orig/rules/60-persistent-storage.rules udev-182/rules/60-persistent-storage.rules
--- udev-182.orig/rules.d/60-persistent-storage.rules	2012-02-23 16:26:16.000000000 +0100
+++ udev-182/rules.d/60-persistent-storage.rules	2012-05-24 11:23:01.000000000 +0200
@@ -16,6 +16,8 @@
 # skip rules for inappropriate block devices
 KERNEL=="fd*|mtd*|nbd*|gnbd*|btibm*|dm-*|md*", GOTO="persistent_storage_end"
 
+KERNEL=="ploop*", GOTO="persistent_storage_end"
+
 # ignore partitions that span the entire disk
 TEST=="whole_disk", GOTO="persistent_storage_end"