mnt: On an unmount propagate clearing of MNT_LOCKED
A prerequisite of calling umount_tree is that the point where the tree
is mounted at is valid to unmount.
If we are propagating the effect of the unmount clear MNT_LOCKED in
every instance where the same filesystem is mounted on the same
mountpoint in the mount tree, as we know (by virtue of the fact
that umount_tree was called) that it is safe to reveal what
is at that mountpoint.
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
diff --git a/fs/namespace.c b/fs/namespace.c
index 083e340..2b12b7a 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1333,6 +1333,9 @@
LIST_HEAD(tmp_list);
struct mount *p;
+ if (how & UMOUNT_PROPAGATE)
+ propagate_mount_unlock(mnt);
+
/* Gather the mounts to umount */
for (p = mnt; p; p = next_mnt(p, mnt)) {
p->mnt.mnt_flags |= MNT_UMOUNT;
