[ 41/82] vfs: umount_tree() might be called on subtree that had never made it

Ben Hutchings
2012-06-08T05:07:16Z

From: Al Viro <viro@zeniv.linux.org.uk>

commit 63d37a84ab6004c235314ffd7a76c5eb28c2fae0 upstream.

__mnt_make_shortterm() in there undoes the effect of __mnt_make_longterm()
we'd done back when we set ->mnt_ns non-NULL; it should not be done to
vfsmounts that had never gone through commit_tree() and friends. Kudos to
lczerner for catching that one...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
fs/namespace.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1244,8 +1244,9 @@
list_del_init(&p->mnt_expire);
list_del_init(&p->mnt_list);
__touch_mnt_namespace(p->mnt_ns);
+ if (p->mnt_ns)
+ __mnt_make_shortterm(p);
p->mnt_ns = NULL;
- __mnt_make_shortterm(p);
list_del_init(&p->mnt_child);
if (p->mnt_parent != p) {
p->mnt_parent->mnt_ghosts++;