[src/trunk]: src/sys/kern Walk down to the lowest mount for "fli_alias".

[hannken <hannken%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/62f4ee6eebd3
branches:  trunk
changeset: 999034:62f4ee6eebd3
user:      hannken <hannken%NetBSD.org@localhost>
date:      Mon May 13 08:16:56 2019 +0000

description:
Walk down to the lowest mount for "fli_alias".

Address PR kern/54195 (null mounts: panic: ...).

diffstat:

 sys/kern/vfs_trans.c |  8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diffs (29 lines):

diff -r 6b567fc0c21c -r 62f4ee6eebd3 sys/kern/vfs_trans.c
--- a/sys/kern/vfs_trans.c      Mon May 13 07:54:52 2019 +0000
+++ b/sys/kern/vfs_trans.c      Mon May 13 08:16:56 2019 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: vfs_trans.c,v 1.59 2019/04/15 13:01:08 hannken Exp $   */
+/*     $NetBSD: vfs_trans.c,v 1.60 2019/05/13 08:16:56 hannken Exp $   */
 
 /*-
  * Copyright (c) 2007 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: vfs_trans.c,v 1.59 2019/04/15 13:01:08 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: vfs_trans.c,v 1.60 2019/05/13 08:16:56 hannken Exp $");
 
 /*
  * File system transaction operations.
@@ -383,7 +383,9 @@
        fli->fli_mount = mp;
        fli->fli_mountinfo = fmi;
        fmi->fmi_ref_cnt += 1;
-       mp = mp->mnt_lower;
+       do {
+               mp = mp->mnt_lower;
+       } while (mp && mp->mnt_lower);
        mutex_exit(&fstrans_mount_lock);
 
        if (mp) {