diff --git a/WHATS_NEW_DM b/WHATS_NEW_DM
index 7e0b578cf..85057edcf 100644
--- a/WHATS_NEW_DM
+++ b/WHATS_NEW_DM
@@ -1,5 +1,6 @@
 Version 1.02.50 - 
 ===============================
+  Fix udev rules to handle spurious events properly.
   Allow use of devmapper header file in C++ mode.
 
 Version 1.02.49 - 4th June 2010
diff --git a/udev/10-dm.rules.in b/udev/10-dm.rules.in
index 0db88093a..b3e2335f8 100644
--- a/udev/10-dm.rules.in
+++ b/udev/10-dm.rules.in
@@ -19,13 +19,6 @@ KERNEL=="device-mapper", NAME="(DM_DIR)/control"
 SUBSYSTEM!="block", GOTO="dm_end"
 KERNEL!="dm-[0-9]*", GOTO="dm_end"
 
-# There is a new change event generated in block layer since kernel
-# version 2.6.32. It adds notification for changes in read-only
-# attribute. We don't want to misinterpret the regular meaning of change
-# events for DM devices and we don't want to apply the rules prematurely,
-# therefore we disable them in this situation.
-ENV{DISK_RO}=="1", GOTO="dm_disable"
-
 # Set proper sbin path, /sbin has higher priority than /usr/sbin.
 ENV{DM_SBIN_PATH}="/sbin"
 TEST!="$env{DM_SBIN_PATH}/dmsetup", ENV{DM_SBIN_PATH}="/usr/sbin"
@@ -37,11 +30,16 @@ TEST!="$env{DM_SBIN_PATH}/dmsetup", GOTO="dm_end"
 # kernels >= 2.6.31 only.
 ENV{DM_COOKIE}=="?*", IMPORT{program}="$env{DM_SBIN_PATH}/dmsetup udevflags $env{DM_COOKIE}"
 
-# Normally, we would test for DM_UDEV_DISABLE_DM_RULES_FLAG here and skip
-# the rules if set. However, we need to set DM_* environment variables
-# for now to properly filter out inappropriate events. This dependency
-# might be removed in the future.
-
+# Device created, major and minor number assigned - "add" event generated.
+# Table loaded - no event generated.
+# Device resumed (or renamed) - "change" event generated.
+# Device removed - "remove" event generated.
+#
+# The dm-X nodes are always created, even on "add" event, we can't suppress
+# that (the node is created even earlier with devtmpfs). All the symlinks
+# (e.g. /dev/mapper) are created in right time after a device has its table
+# loaded and is properly resumed. For this reason, direct use of dm-X nodes
+# is not recommended.
 ACTION!="add|change", GOTO="dm_end"
 
 # There is no cookie set nor any flags encoded in events not originating
@@ -55,6 +53,7 @@ IMPORT{db}="DM_UDEV_DISABLE_DISK_RULES_FLAG"
 IMPORT{db}="DM_UDEV_DISABLE_OTHER_RULES_FLAG"
 IMPORT{db}="DM_UDEV_LOW_PRIORITY_FLAG"
 IMPORT{db}="DM_UDEV_DISABLE_LIBRARY_FALLBACK_FLAG"
+IMPORT{db}="DM_UDEV_PRIMARY_SOURCE_FLAG"
 IMPORT{db}="DM_UDEV_FLAG7"
 IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG0"
 IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG1"
@@ -66,12 +65,19 @@ IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG6"
 IMPORT{db}="DM_SUBSYSTEM_UDEV_FLAG7"
 LABEL="dm_flags_done"
 
-# Normally, we operate on "change" events only. But when
-# coldplugging, there's an "add" event present. We have to
-# recognize this and do our actions in this particular
-# situation, too. Also, we don't want the nodes to be
-# created prematurely on "add" events while not coldplugging.
-ACTION=="add", ENV{STARTUP}!="1", NAME="", GOTO="dm_end"
+# Normally, we operate on "change" events. But when coldplugging, there's an
+# "add" event present. We have to recognize this and do our actions in this
+# particular situation, too. Also, we don't want the nodes to be created
+# prematurely on "add" events while not coldplugging. We check
+# DM_UDEV_PRIMARY_SOURCE_FLAG to see if the device was activated correctly
+# before and if not, we ignore the "add" event totally. This way we can support
+# udev triggers generating "add" events (e.g. "udevadm trigger --action=add" or
+# "echo add > /sys/block/<dm_device>/uevent"). The trigger with "add" event is
+# also used at boot to reevaluate udev rules for all existing devices activated
+# before (e.g. in initrd). If udev is used in initrd, we require the udev init
+# script to not remove the existing udev database so we can reuse the information
+# stored at the time of device activation in the initrd.
+ACTION=="add", ENV{DM_UDEV_PRIMARY_SOURCE_FLAG}!="1", GOTO="dm_disable"
 
 # "dm" sysfs subdirectory is available in newer versions of DM
 # only (kernels >= 2.6.29). We have to check for its existence