device-mapper-multipath/0015-RH-add-followover.patch

---
 libmultipath/dict.c        |   12 ++++++++++++
 libmultipath/print.c       |    2 ++
 libmultipath/structs.h     |    3 ++-
 multipath/multipath.conf.5 |    5 +++++
 multipathd/main.c          |   29 ++++++++++++++++++++++++++++-
 5 files changed, 49 insertions(+), 2 deletions(-)

Index: multipath-tools-120123/libmultipath/dict.c
===================================================================
--- multipath-tools-120123.orig/libmultipath/dict.c
+++ multipath-tools-120123/libmultipath/dict.c
@@ -406,6 +406,8 @@ default_failback_handler(vector strvec)
 		conf->pgfailback = -FAILBACK_MANUAL;
 	else if (strlen(buff) == 9 && !strcmp(buff, "immediate"))
 		conf->pgfailback = -FAILBACK_IMMEDIATE;
+	else if (strlen(buff) == 10 && !strcmp(buff, "followover"))
+		conf->pgfailback = -FAILBACK_FOLLOWOVER;
 	else
 		conf->pgfailback = atoi(buff);
 
@@ -1031,6 +1033,8 @@ hw_failback_handler(vector strvec)
 		hwe->pgfailback = -FAILBACK_MANUAL;
 	else if (strlen(buff) == 9 && !strcmp(buff, "immediate"))
 		hwe->pgfailback = -FAILBACK_IMMEDIATE;
+	else if (strlen(buff) == 10 && !strcmp(buff, "followover"))
+		hwe->pgfailback = -FAILBACK_FOLLOWOVER;
 	else
 		hwe->pgfailback = atoi(buff);
 
@@ -1303,6 +1307,8 @@ mp_failback_handler(vector strvec)
 		mpe->pgfailback = -FAILBACK_MANUAL;
 	else if (strlen(buff) == 9 && !strcmp(buff, "immediate"))
 		mpe->pgfailback = -FAILBACK_IMMEDIATE;
+	else if (strlen(buff) == 10 && !strcmp(buff, "followover"))
+		mpe->pgfailback = -FAILBACK_FOLLOWOVER;
 	else
 		mpe->pgfailback = atoi(buff);
 
@@ -1646,6 +1652,8 @@ snprint_mp_failback (char * buff, int le
 		return snprintf(buff, len, "manual");
 	case -FAILBACK_IMMEDIATE:
 		return snprintf(buff, len, "immediate");
+	case -FAILBACK_FOLLOWOVER:
+		return snprintf(buff, len, "followover");
 	default:
 		return snprintf(buff, len, "%i", mpe->pgfailback);
 	}
@@ -1985,6 +1993,8 @@ snprint_hw_failback (char * buff, int le
 		return snprintf(buff, len, "manual");
 	case -FAILBACK_IMMEDIATE:
 		return snprintf(buff, len, "immediate");
+	case -FAILBACK_FOLLOWOVER:
+		return snprintf(buff, len, "followover");
 	default:
 		return snprintf(buff, len, "%i", hwe->pgfailback);
 	}
@@ -2243,6 +2253,8 @@ snprint_def_failback (char * buff, int l
 		return snprintf(buff, len, "manual");
 	case -FAILBACK_IMMEDIATE:
 		return snprintf(buff, len, "immediate");
+	case -FAILBACK_FOLLOWOVER:
+		return snprintf(buff, len, "followover");
 	default:
 		return snprintf(buff, len, "%i", conf->pgfailback);
 	}
Index: multipath-tools-120123/libmultipath/print.c
===================================================================
--- multipath-tools-120123.orig/libmultipath/print.c
+++ multipath-tools-120123/libmultipath/print.c
@@ -143,6 +143,8 @@ snprint_failback (char * buff, size_t le
 {
 	if (mpp->pgfailback == -FAILBACK_IMMEDIATE)
 		return snprintf(buff, len, "immediate");
+	if (mpp->pgfailback == -FAILBACK_FOLLOWOVER)
+		return snprintf(buff, len, "followover");
 
 	if (!mpp->failback_tick)
 		return snprintf(buff, len, "-");
Index: multipath-tools-120123/libmultipath/structs.h
===================================================================
--- multipath-tools-120123.orig/libmultipath/structs.h
+++ multipath-tools-120123/libmultipath/structs.h
@@ -39,7 +39,8 @@ enum rr_weight_mode {
 enum failback_mode {
 	FAILBACK_UNDEF,
 	FAILBACK_MANUAL,
-	FAILBACK_IMMEDIATE
+	FAILBACK_IMMEDIATE,
+	FAILBACK_FOLLOWOVER
 };
 
 enum sysfs_buses {
Index: multipath-tools-120123/multipathd/main.c
===================================================================
--- multipath-tools-120123.orig/multipathd/main.c
+++ multipath-tools-120123/multipathd/main.c
@@ -1011,6 +1011,32 @@ mpvec_garbage_collector (struct vectors
 	}
 }
 
+/* This is called after a path has started working again. It the multipath
+ * device for this path uses the followover failback type, and this is the
+ * best pathgroup, and this is the first path in the pathgroup to come back
+ * up, then switch to this pathgroup */
+static int
+followover_should_failback(struct path * pp)
+{
+	struct pathgroup * pgp;
+	struct path *pp1;
+	int i;
+
+	if (pp->mpp->pgfailback != -FAILBACK_FOLLOWOVER ||
+	    !pp->mpp->pg || !pp->pgindex ||
+	    pp->pgindex != pp->mpp->bestpg)
+		return 0;
+
+	pgp = VECTOR_SLOT(pp->mpp->pg, pp->pgindex - 1);
+	vector_foreach_slot(pgp->paths, pp1, i) {
+		if (pp1 == pp)
+			continue;
+		if (pp1->state != PATH_DOWN && pp1->state != PATH_SHAKY)
+			return 0;
+	}
+	return 1;
+}
+
 static void
 defered_failback_tick (vector mpvec)
 {
@@ -1238,7 +1264,8 @@ check_path (struct vectors * vecs, struc
 		    (new_path_up || pp->mpp->failback_tick <= 0))
 			pp->mpp->failback_tick =
 				pp->mpp->pgfailback + 1;
-		else if (pp->mpp->pgfailback == -FAILBACK_IMMEDIATE)
+		else if (pp->mpp->pgfailback == -FAILBACK_IMMEDIATE ||
+			 followover_should_failback(pp))
 			switch_pathgroup(pp->mpp);
 	}
 }
Index: multipath-tools-120123/multipath/multipath.conf.5
===================================================================
--- multipath-tools-120123.orig/multipath/multipath.conf.5
+++ multipath-tools-120123/multipath/multipath.conf.5
@@ -258,6 +258,11 @@ active paths.
 .B manual
 Do not perform automatic failback.
 .TP
+.B followover
+Only perform automatic failback when the first path of a pathgroup
+becomes active. This keeps a node from automatically failing back when
+another node requested the failover.
+.TP
 .B values > 0
 deferred failback (time to defer in seconds)
 .TP