device-mapper-multipath/0003-RH-add-followover.patch

---
 libmultipath/dict.c        |   12 ++++++++++++
 libmultipath/discovery.c   |    6 +++---
 libmultipath/print.c       |    2 ++
 libmultipath/structs.h     |    4 +++-
 multipath/main.c           |    2 +-
 multipath/multipath.conf.5 |    5 +++++
 multipathd/main.c          |   35 ++++++++++++++++++++++++++++++++++-
 7 files changed, 60 insertions(+), 6 deletions(-)

Index: multipath-tools-120518/libmultipath/dict.c
===================================================================
--- multipath-tools-120518.orig/libmultipath/dict.c
+++ multipath-tools-120518/libmultipath/dict.c
@@ -398,6 +398,8 @@ 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);
 
@@ -1053,6 +1055,8 @@ 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);
 
@@ -1351,6 +1355,8 @@ 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);
 
@@ -1769,6 +1775,8 @@ 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);
 	}
@@ -2130,6 +2138,8 @@ 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);
 	}
@@ -2394,6 +2404,8 @@ 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-120518/libmultipath/print.c
===================================================================
--- multipath-tools-120518.orig/libmultipath/print.c
+++ multipath-tools-120518/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-120518/libmultipath/structs.h
===================================================================
--- multipath-tools-120518.orig/libmultipath/structs.h
+++ multipath-tools-120518/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 {
@@ -151,6 +152,7 @@ struct path {
 	int offline;
 	int state;
 	int dmstate;
+	int chkrstate;
 	int failcount;
 	int priority;
 	int pgindex;
Index: multipath-tools-120518/multipathd/main.c
===================================================================
--- multipath-tools-120518.orig/multipathd/main.c
+++ multipath-tools-120518/multipathd/main.c
@@ -995,6 +995,32 @@ 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->chkrstate != PATH_DOWN && pp1->chkrstate != PATH_SHAKY)
+			return 0;
+	}
+	return 1;
+}
+
 static void
 defered_failback_tick (vector mpvec)
 {
@@ -1092,6 +1118,8 @@ check_path (struct vectors * vecs, struc
 {
 	int newstate;
 	int new_path_up = 0;
+	int chkr_new_path_up = 0;
+	int oldchkrstate = pp->chkrstate;
 
 	if (!pp->mpp)
 		return;
@@ -1130,6 +1158,7 @@ check_path (struct vectors * vecs, struc
 			pp->dev);
 		pp->dmstate = PSTATE_UNDEF;
 	}
+	pp->chkrstate = newstate;
 	if (newstate != pp->state) {
 		int oldstate = pp->state;
 		pp->state = newstate;
@@ -1182,6 +1211,9 @@ check_path (struct vectors * vecs, struc
 
 		new_path_up = 1;
 
+		if (oldchkrstate != PATH_UP && oldchkrstate != PATH_GHOST)
+			chkr_new_path_up = 1;
+
 		/*
 		 * if at least one path is up in a group, and
 		 * the group is disabled, re-enable it
@@ -1233,7 +1265,8 @@ 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 ||
+			 (chkr_new_path_up && followover_should_failback(pp)))
 			switch_pathgroup(pp->mpp);
 	}
 }
Index: multipath-tools-120518/multipath/multipath.conf.5
===================================================================
--- multipath-tools-120518.orig/multipath/multipath.conf.5
+++ multipath-tools-120518/multipath/multipath.conf.5
@@ -254,6 +254,11 @@ 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
Index: multipath-tools-120518/libmultipath/discovery.c
===================================================================
--- multipath-tools-120518.orig/libmultipath/discovery.c
+++ multipath-tools-120518/libmultipath/discovery.c
@@ -878,13 +878,13 @@ pathinfo (struct path *pp, vector hwtabl
 
 	if (mask & DI_CHECKER) {
 		if (path_state == PATH_UP) {
-			pp->state = get_state(pp, 0);
+			pp->chkrstate = pp->state = get_state(pp, 0);
 			if (pp->state == PATH_UNCHECKED ||
 			    pp->state == PATH_WILD)
 				goto blank;
 		} else {
 			condlog(3, "%s: path inaccessible", pp->dev);
-			pp->state = path_state;
+			pp->chkrstate = pp->state = path_state;
 		}
 	}
 
@@ -912,7 +912,7 @@ blank:
 	 * Recoverable error, for example faulty or offline path
 	 */
 	memset(pp->wwid, 0, WWID_SIZE);
-	pp->state = PATH_DOWN;
+	pp->chkrstate = pp->state = PATH_DOWN;
 
 	return 0;
 }
Index: multipath-tools-120518/multipath/main.c
===================================================================
--- multipath-tools-120518.orig/multipath/main.c
+++ multipath-tools-120518/multipath/main.c
@@ -144,7 +144,7 @@ update_paths (struct multipath * mpp)
 					/*
 					 * path is not in sysfs anymore
 					 */
-					pp->state = PATH_DOWN;
+					pp->chkrstate = pp->state = PATH_DOWN;
 					continue;
 				}
 				pp->mpp = mpp;