Support udev flags even when udev_sync is disabled or not compiled in.

This provides better support for environments where udev rules are installed
but udev_sync is not compiled in (however, using udev_sync is highly
recommended). It also provides consistent and expected functionality even
when '--noudevsync' option is used.

There is still requirement for kernel >= 2.6.31 for the flags to work though
(it uses DM cookies to pass the flags into the kernel and set them in udev
event environment that we can read in udev rules).

diff --git a/WHATS_NEW_DM b/WHATS_NEW_DM
index 9751a03..50c59c2 100644
--- a/WHATS_NEW_DM
+++ b/WHATS_NEW_DM
@@ -1,5 +1,6 @@
 Version 1.02.40 -
 ===================================
+  Support udev flags even when udev_sync is disabled or not compiled in.
   Remove 'last_rule' from udev rules: honor ENV{DM_UDEV_DISABLE_OTHER_RULES_FLAG}.
 
 Version 1.02.39 - 26th October 2009
diff --git a/libdm/ioctl/libdm-iface.c b/libdm/ioctl/libdm-iface.c
index e49ac71..df30adc 100644
--- a/libdm/ioctl/libdm-iface.c
+++ b/libdm/ioctl/libdm-iface.c
@@ -1535,6 +1535,7 @@ static int _create_and_load_v4(struct dm_task *dmt)
 	task->gid = dmt->gid;
 	task->mode = dmt->mode;
 	/* FIXME: Just for udev_check in dm_task_run. Can we avoid this? */
+	task->event_nr = dmt->event_nr & DM_UDEV_FLAGS_MASK;
 	task->cookie_set = dmt->cookie_set;
 
 	r = dm_task_run(task);
diff --git a/libdm/libdevmapper.h b/libdm/libdevmapper.h
index b339683..fcafbee 100644
--- a/libdm/libdevmapper.h
+++ b/libdm/libdevmapper.h
@@ -1031,6 +1031,10 @@ void dm_report_field_set_value(struct dm_report_field *field, const void *value,
  * of udev rules we use by decoding the cookie prefix. When doing the
  * notification, we replace the cookie prefix with DM_COOKIE_MAGIC,
  * so we notify the right semaphore.
+ * It is still possible to use cookies for passing the flags to udev
+ * rules even when udev_sync is disabled. The base part of the cookie
+ * will be zero (there's no notification semaphore) and prefix will be
+ * set then. However, having udev_sync enabled is highly recommended.
  */
 #define DM_COOKIE_MAGIC 0x0D4D
 #define DM_UDEV_FLAGS_MASK 0xFFFF0000
@@ -1075,7 +1079,7 @@ void dm_report_field_set_value(struct dm_report_field *field, const void *value,
 int dm_cookie_supported(void);
 
 /*
- * Udev notification functions.
+ * Udev synchronisation functions.
  */
 void dm_udev_set_sync_support(int sync_with_udev);
 int dm_udev_get_sync_support(void);
diff --git a/libdm/libdm-common.c b/libdm/libdm-common.c
index ede17b2..adf450e 100644
--- a/libdm/libdm-common.c
+++ b/libdm/libdm-common.c
@@ -885,6 +885,8 @@ int dm_udev_get_sync_support(void)
 
 int dm_task_set_cookie(struct dm_task *dmt, uint32_t *cookie, uint16_t flags)
 {
+	if (dm_cookie_supported())
+		dmt->event_nr = flags << DM_UDEV_FLAGS_SHIFT;
 	*cookie = 0;
 
 	return 1;
@@ -1140,8 +1142,11 @@ int dm_task_set_cookie(struct dm_task *dmt, uint32_t *cookie, uint16_t flags)
 {
 	int semid;
 
+	if (dm_cookie_supported())
+		dmt->event_nr = flags << DM_UDEV_FLAGS_SHIFT;
+
 	if (!dm_udev_get_sync_support()) {
-		dmt->event_nr = *cookie = 0;
+		*cookie = 0;
 		return 1;
 	}
 
@@ -1158,8 +1163,7 @@ int dm_task_set_cookie(struct dm_task *dmt, uint32_t *cookie, uint16_t flags)
 		goto bad;
 	}
 
-	dmt->event_nr = (~DM_UDEV_FLAGS_MASK & *cookie) |
-			(flags << DM_UDEV_FLAGS_SHIFT);
+	dmt->event_nr |= ~DM_UDEV_FLAGS_MASK & *cookie;
 	dmt->cookie_set = 1;
 
 	log_debug("Udev cookie 0x%" PRIx32 " (semid %d) assigned to dm_task "
diff --git a/libdm/libdm-deptree.c b/libdm/libdm-deptree.c
index c98fb34..1465fd3 100644
--- a/libdm/libdm-deptree.c
+++ b/libdm/libdm-deptree.c
@@ -1039,7 +1039,7 @@ int dm_tree_deactivate_children(struct dm_tree_node *dnode,
 			continue;
 
 		if (!_deactivate_node(name, info.major, info.minor,
-				      &dnode->dtree->cookie, dnode->udev_flags)) {
+				      &child->dtree->cookie, child->udev_flags)) {
 			log_error("Unable to deactivate %s (%" PRIu32
 				  ":%" PRIu32 ")", name, info.major,
 				  info.minor);
diff --git a/tools/dmsetup.c b/tools/dmsetup.c
index a7f1d25..17548e4 100644
--- a/tools/dmsetup.c
+++ b/tools/dmsetup.c
@@ -821,9 +821,17 @@ static int _udevcomplete(int argc, char **argv, void *data __attribute((unused))
 	if (!(cookie = _get_cookie_value(argv[1])))
 		return 0;
 
-	/* strip flags from the cookie and use cookie magic instead */
-	cookie = (cookie & ~DM_UDEV_FLAGS_MASK) |
-		  (DM_COOKIE_MAGIC << DM_UDEV_FLAGS_SHIFT);
+	/*
+	 * Strip flags from the cookie and use cookie magic instead.
+	 * If the cookie has non-zero prefix and the base is zero then
+	 * this one carries flags to control udev rules only and it is
+	 * not meant to be for notification. Return with success in this
+	 * situation.
+	 */
+	if (!(cookie &= ~DM_UDEV_FLAGS_MASK))
+		return 1;
+
+	cookie |= DM_COOKIE_MAGIC << DM_UDEV_FLAGS_SHIFT;
 
 	return dm_udev_complete(cookie);
 }