[dm-devel] [PATCH v2 07/11] multipathd: use remove_map_callback for delayed reconfigure

[mwilck at suse.com]

From: Martin Wilck <mwilck at suse.com>

If multipathd needs to delay reconfigure() because it's waiting for a map
creation uevent, it can happen that child() isn't woken up if the map
being waited for is removed before the uevent arrives. Fix this by
unblocking reconfigure() with the remove_map_callback() function.

Signed-off-by: Martin Wilck <mwilck at suse.com>
---
 multipathd/main.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/multipathd/main.c b/multipathd/main.c
index f3b8eb4..4721cd8 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -319,6 +319,17 @@ static bool unblock_reconfigure(void)
 	return was_delayed;
 }
 
+/*
+ * Make sure child() is woken up when a map is removed that multipathd
+ * is currently waiting for.
+ * Overrides libmultipath's weak symbol by the same name
+ */
+void remove_map_callback(struct multipath *mpp)
+{
+	if (mpp->wait_for_udev > 0)
+		unblock_reconfigure();
+}
+
 void schedule_reconfigure(enum force_reload_types requested_type)
 {
 	pthread_mutex_lock(&config_lock);
-- 
2.35.1