udev: try again to create /run/udev/queue when queueing the next event

This is mostly a paranoia, but if we failed to create /run/udev/queue
for some reasons on queueing an event, previously we would never create
the file until once the queue became empty. This makes in such case we
try to create the file again when queueing the next event.

src/udev/udev-manager.c

@@ -852,16 +852,17 @@ static int event_queue_insert(Manager *manager, sd_device *dev) {
                 .state = EVENT_QUEUED,
         };
 
-        if (!manager->events) {
+        LIST_APPEND(event, manager->events, event);
+        log_device_uevent(dev, "Device is queued");
+
+        if (!manager->queue_file_created) {
                 r = touch("/run/udev/queue");
                 if (r < 0)
                         log_warning_errno(r, "Failed to touch /run/udev/queue, ignoring: %m");
+                else
+                        manager->queue_file_created = true;
         }
 
-        LIST_APPEND(event, manager->events, event);
-
-        log_device_uevent(dev, "Device is queued");
-
         return 0;
 }
 
@@ -1155,13 +1156,12 @@ static int manager_unlink_queue_file(Manager *manager) {
 
         /* There are no queued events. Let's remove /run/udev/queue and clean up the idle processes. */
         if (unlink("/run/udev/queue") < 0) {
-                if (errno == ENOENT)
-                        return 0;
+                if (errno != ENOENT)
+                        return log_warning_errno(errno, "Failed to unlink /run/udev/queue: %m");
+        } else
+                log_debug("No events are queued, removed /run/udev/queue.");
 
-                return log_warning_errno(errno, "Failed to unlink /run/udev/queue: %m");
-        }
-
-        log_debug("No events are queued, removed /run/udev/queue.");
+        manager->queue_file_created = false;
         return 0;
 }
 

src/udev/udev-manager.h

@@ -61,6 +61,7 @@ typedef struct Manager {
         UdevConfig config_by_control;
         UdevConfig config;
 
+        bool queue_file_created;
         bool stop_exec_queue;
         bool exit;
 } Manager;