autofs-5.1.6 - fix program map multi-mount lookup after mount fail

From: Ian Kent <raven@themaw.net>

For the case of a singleton multi-mount program map lookup following
a mount fail (and the negative timeout has passed) the lookup key is
what's expected for an indirect map key but the the root offset map
entry already exists. This causes autofs to think it has an incorrect
lookup key and it fails the lookup when it should take the opptunity
to delete and update the cache entry since it's not actually in use
yet.

If a check is done to see if the lookup is for the root offset,
deleting the entry fails because it contains an offset. Later when
parsing is done the offset will get updated and can get out of sync
with the entry of the multi-mount owner. That's not a problem as the
offsets would be deleted on eventual expire but it's best to clean
out the entry and start a fresh so the most up to date map entry
is being used.

Signed-off-by: Ian Kent <raven@themaw.net>
---
 CHANGELOG                |    1 +
 modules/lookup_program.c |    7 +++++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG b/CHANGELOG
index 981a0333..3c784d34 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,7 @@
 xx/xx/2020 autofs-5.1.7
 - make bind mounts propagation slave by default.
 - update ldap READMEs and schema definitions.
+- fix program map multi-mount lookup after mount fail.
 
 07/10/2019 autofs-5.1.6
 - support strictexpire mount option.
diff --git a/modules/lookup_program.c b/modules/lookup_program.c
index fcb1af74..ca209488 100644
--- a/modules/lookup_program.c
+++ b/modules/lookup_program.c
@@ -646,7 +646,7 @@ int lookup_mount(struct autofs_point *ap, const char *name, int name_len, void *
 				 name_len, ent, ctxt->parse->context);
 			goto out_free;
 		} else {
-			if (me->multi) {
+			if (me->multi && me->multi != me) {
 				cache_unlock(mc);
 				warn(ap->logopt, MODPREFIX
 				     "unexpected lookup for active multi-mount"
@@ -656,8 +656,11 @@ int lookup_mount(struct autofs_point *ap, const char *name, int name_len, void *
 			cache_unlock(mc);
 			cache_writelock(mc);
 			me = cache_lookup_distinct(mc, name);
-			if (me)
+			if (me) {
+				if (me->multi)
+					cache_delete_offset_list(mc, name);
 				cache_delete(mc, name);
+			}
 			cache_unlock(mc);
 		}
 	}