On Wed, Jun 11, 2025 at 01:05:52PM +0200, Christian Brauner wrote:
> > - if (beneath)
> > - mnt_change_mountpoint(source_mnt, smp, top_mnt);
> > - commit_tree(source_mnt);
> > + hlist_add_head(&source_mnt->mnt_hash, &tree_list);
>
> Please add a comment here. Right now it's easy to understand even with
> your mnt_change_mountpoint() changes. Afterwards the cases are folded
> and imho that leaves readers wondering why that's correct.
Hmm... Does the incremental below look sane for you?
diff --git a/fs/namespace.c b/fs/namespace.c
index d5a7d7da3932..15b7959b1771 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2675,6 +2675,13 @@ static int attach_recursive_mnt(struct mount *source_mnt,
}
mnt_set_mountpoint(dest_mnt, dest_mp, source_mnt);
+ /*
+ * Now the original copy is in the same state as the secondaries -
+ * its root attached to mountpoint, but not hashed and all mounts
+ * in it are either in our namespace or in no namespace at all.
+ * Add the original to the list of copies and deal with the
+ * rest of work for all of them uniformly.
+ */
hlist_add_head(&source_mnt->mnt_hash, &tree_list);
hlist_for_each_entry_safe(child, n, &tree_list, mnt_hash) {
