[PATCH] namespace.c: fix mnt_namespace zeroing for expired mounts

This patch clears mnt_namespace in an expired mount.

If mnt_namespace is not cleared, it's possible to attach a new mount to the
already detached mount, because check_mnt() can return true.

The effect is a resource leak, since the resulting tree will never be
freed.

Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/fs/namespace.c b/fs/namespace.c
index 2b4635e43ae84024cac1564231a834f93afc6590..7fd56eeb21bf026642add713064da6aa8dfebb61 100644 (file)
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -847,6 +847,7 @@ static void expire_mount(struct vfsmount *mnt, struct list_head *mounts)
 
                /* delete from the namespace */
                list_del_init(&mnt->mnt_list);
+               mnt->mnt_namespace = NULL;
                detach_mnt(mnt, &old_nd);
                spin_unlock(&vfsmount_lock);
                path_release(&old_nd);