[dm-devel] [PATCH V2 07/11] libmultipath: don't count PRIO_UNDEF paths for pathgroup priority

[Benjamin Marzinski]

When multipath is not set to group_by_prio, different paths in a
pathgroup can have different priorities. If there is a problem getting
the priority of an active path, its priority will be set to PRIO_UNDEF.
This will change the priority of the whole pathgroup, even though it's
likely that this is simply a temporary error. Instead, do not count
PRIO_UNDEF paths towards to priority of the path group, unless there are
no paths that have an actual priority. This will not effect the priority
of multipath devices with group_by_prio, since all paths in a pathgroup
will have the same priority.

Reviewed-by: Martin Wilck <mwilck at suse.com>
Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
---
 libmultipath/switchgroup.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/libmultipath/switchgroup.c b/libmultipath/switchgroup.c
index 6fdfcfa7..b1e1f39b 100644
--- a/libmultipath/switchgroup.c
+++ b/libmultipath/switchgroup.c
@@ -12,6 +12,7 @@ void path_group_prio_update(struct pathgroup *pgp)
 	int i;
 	int priority = 0;
 	int marginal = 0;
+	int defined_prios = 0;
 	struct path * pp;
 
 	pgp->enabled_paths = 0;
@@ -24,12 +25,17 @@ void path_group_prio_update(struct pathgroup *pgp)
 			marginal++;
 		if (pp->state == PATH_UP ||
 		    pp->state == PATH_GHOST) {
-			priority += pp->priority;
+			if (pp->priority != PRIO_UNDEF) {
+				defined_prios++;
+				priority += pp->priority;
+			}
 			pgp->enabled_paths++;
 		}
 	}
-	if (pgp->enabled_paths)
-		pgp->priority = priority / pgp->enabled_paths;
+	if (defined_prios)
+		pgp->priority = priority / defined_prios;
+	else if (pgp->enabled_paths)
+		pgp->priority = PRIO_UNDEF;
 	else
 		pgp->priority = 0;
 	if (marginal && marginal == i)
-- 
2.17.2