From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Benjamin Marzinski <bmarzins@redhat.com>
Date: Mon, 18 Feb 2019 13:32:45 -0600
Subject: [PATCH] BZ 1673167: Fix miscounting active paths

When multipathd gets a change uevent, it calls pathinfo with DI_NOIO.
This sets the path state to the return value of path_offline(). If a
path is in the PATH_DOWN state but path_offline() returns PATH_UP, when
that path gets a change event, its state will get moved to PATH_UP
without either reinstating the path, or reloading the map.  The next
call to check_path() will move the path back to PATH_DOWN. Since
check_path() simply increments and decrements nr_active instead of
calculating it based on the actual number of active paths, nr_active
will get decremented a second time for this failed path, potentially
putting the multipath device into recovery mode.

To avoid this situation, pathinfo() will now only set pp->state with
DI_NOIO if DI_CHECKER is also set. This isn't set in uev_update_path()
to avoid changing the path state in this case.

Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
---
 libmultipath/discovery.c | 11 ++++++-----
 multipath/main.c         |  2 +-
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
index b267f07..5de087c 100644
--- a/libmultipath/discovery.c
+++ b/libmultipath/discovery.c
@@ -1914,11 +1914,12 @@ int pathinfo(struct path *pp, struct config *conf, int mask)
 	if (path_state == PATH_REMOVED)
 		goto blank;
 	else if (mask & DI_NOIO) {
-		/*
-		 * Avoid any IO on the device itself.
-		 * Behave like DI_CHECKER in the "path unavailable" case.
-		 */
-		pp->chkrstate = pp->state = path_state;
+		if (mask & DI_CHECKER)
+			/*
+			 * Avoid any IO on the device itself.
+			 * simply use the path_offline() return as its state
+			 */
+			pp->chkrstate = pp->state = path_state;
 		return PATHINFO_OK;
 	}
 
diff --git a/multipath/main.c b/multipath/main.c
index 2c4054d..0545226 100644
--- a/multipath/main.c
+++ b/multipath/main.c
@@ -345,7 +345,7 @@ static int check_usable_paths(struct config *conf,
 			pp->udev = get_udev_device(pp->dev_t, DEV_DEVT);
 			if (pp->udev == NULL)
 				continue;
-			if (pathinfo(pp, conf, DI_SYSFS|DI_NOIO) != PATHINFO_OK)
+			if (pathinfo(pp, conf, DI_SYSFS|DI_NOIO|DI_CHECKER) != PATHINFO_OK)
 				continue;
 
 			if (pp->state == PATH_UP &&
-- 
2.17.2