mnt: In umount_tree reuse mnt_list instead of mnt_hash

umount_tree builds a list of mounts that need to be unmounted.
Utilize mnt_list for this purpose instead of mnt_hash.  This begins to
allow keeping a mount on the mnt_hash after it is unmounted, which is
necessary for a properly functioning MNT_LOCKED implementation.

The fact that mnt_list is an ordinary list makding available list_move
is nice bonus.

Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/fs/pnode.c b/fs/pnode.c
index 260ac8f898a4..bf012af709dd 100644
--- a/fs/pnode.c
+++ b/fs/pnode.c
@@ -384,7 +384,7 @@ static void __propagate_umount(struct mount *mnt)
 		if (child && list_empty(&child->mnt_mounts)) {
 			list_del_init(&child->mnt_child);
 			hlist_del_init_rcu(&child->mnt_hash);
-			hlist_add_before_rcu(&child->mnt_hash, &mnt->mnt_hash);
+			list_move_tail(&child->mnt_list, &mnt->mnt_list);
 		}
 	}
 }
@@ -396,11 +396,11 @@ static void __propagate_umount(struct mount *mnt)
  *
  * vfsmount lock must be held for write
  */
-int propagate_umount(struct hlist_head *list)
+int propagate_umount(struct list_head *list)
 {
 	struct mount *mnt;
 
-	hlist_for_each_entry(mnt, list, mnt_hash)
+	list_for_each_entry(mnt, list, mnt_list)
 		__propagate_umount(mnt);
 	return 0;
 }