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