[dm-devel] [PATCH 1/7] multipathd: remove missing paths on startup

[Benjamin Marzinski]

If a path device was removed from the system while multipathd was not
running, multipathd would not remove the path from the multipath table
on start-up, or on a weak reconfigure. update_pathvec_from_dm() would
return that a reload was necessary, but that information wasn't
propigated back to where it could be used to reload the device.

Multipath devices now remember if they need to be reloaded, and if so,
force_reload is set in select_action().  This means that even when
configure is called with FORCE_RELOAD_WEAK, these devices will still be
reloaded.

Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
---
 libmultipath/configure.c   | 2 ++
 libmultipath/devmapper.c   | 2 ++
 libmultipath/structs.h     | 1 +
 libmultipath/structs_vec.c | 1 +
 4 files changed, 6 insertions(+)

diff --git a/libmultipath/configure.c b/libmultipath/configure.c
index eb8ec1bd..f1a890af 100644
--- a/libmultipath/configure.c
+++ b/libmultipath/configure.c
@@ -715,6 +715,8 @@ void select_action (struct multipath *mpp, const struct _vector *curmp,
 
 	cmpp = find_mp_by_wwid(curmp, mpp->wwid);
 	cmpp_by_name = find_mp_by_alias(curmp, mpp->alias);
+	if (mpp->need_reload || (cmpp && cmpp->need_reload))
+		force_reload = 1;
 
 	if (!cmpp_by_name) {
 		if (cmpp) {
diff --git a/libmultipath/devmapper.c b/libmultipath/devmapper.c
index c05dc201..3e1a7260 100644
--- a/libmultipath/devmapper.c
+++ b/libmultipath/devmapper.c
@@ -522,6 +522,8 @@ freeout:
 addout:
 	dm_task_destroy (dmt);
 
+	if (r)
+		mpp->need_reload = false;
 	return r;
 }
 
diff --git a/libmultipath/structs.h b/libmultipath/structs.h
index 399540e7..d0b266b7 100644
--- a/libmultipath/structs.h
+++ b/libmultipath/structs.h
@@ -355,6 +355,7 @@ struct multipath {
 	int retain_hwhandler;
 	int deferred_remove;
 	bool in_recovery;
+	bool need_reload;
 	int san_path_err_threshold;
 	int san_path_err_forget_rate;
 	int san_path_err_recovery_time;
diff --git a/libmultipath/structs_vec.c b/libmultipath/structs_vec.c
index 85d97ac1..e52db0c4 100644
--- a/libmultipath/structs_vec.c
+++ b/libmultipath/structs_vec.c
@@ -237,6 +237,7 @@ bool update_pathvec_from_dm(vector pathvec, struct multipath *mpp,
 		free_pathgroup(pgp, KEEP_PATHS);
 		must_reload = true;
 	}
+	mpp->need_reload = mpp->need_reload || must_reload;
 	return must_reload;
 }
 
-- 
2.17.2