libmutipath: continue to use old state on PATH_PENDING
authorBenjamin Marzinski <bmarzins@redhat.com>
Sat, 30 Mar 2019 06:05:57 +0000 (01:05 -0500)
committerChristophe Varoqui <christophe.varoqui@opensvc.com>
Thu, 18 Apr 2019 11:03:36 +0000 (13:03 +0200)
When pathinfo() sets pp->state to PATH_PENDING, it can cause problems
with path checking.  It should act more like check_path(). When
check_path() sees a new state of PATH_PENDING, it doesn't update the
path state at all, so a path's old state is normally never PATH_PENDING.

As and example of the problems of setting a path to PATH_PENDING, If
check_path() sets a path's state to PATH_UP, then a call to pathinfo()
sets the state to PATH_PENDING, and then another call the check_path()
sets the state to PATH_DOWN, multipathd won't fail the path in the
kernel. Also, if a path's state is PATH_PENDING, and nr_active is
recalculated, that path will count as down, even if the state was
previously PATH_UP. If a path already has a state of PATH_WILD or
PATH_UNCHECKED, changing it to PATH_PENDING won't hurt anything, and it
will help anyone who sees it know what's actually happening. But
otherwise, pathinfo() should leave the previous state alone.

Reviewed-by: Martin Wilck <mwilck@suse.com>
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
libmultipath/discovery.c

index b08cb2d..28c00e5 100644 (file)
@@ -1946,8 +1946,11 @@ int pathinfo(struct path *pp, struct config *conf, int mask)
 
        if (mask & DI_CHECKER) {
                if (path_state == PATH_UP) {
-                       pp->chkrstate = pp->state = get_state(pp, conf, 0,
-                                                             path_state);
+                       int newstate = get_state(pp, conf, 0, path_state);
+                       if (newstate != PATH_PENDING ||
+                           pp->state == PATH_UNCHECKED ||
+                           pp->state == PATH_WILD)
+                               pp->chkrstate = pp->state = newstate;
                        if (pp->state == PATH_TIMEOUT)
                                pp->state = PATH_DOWN;
                        if (pp->state == PATH_UP && !pp->size) {