Re: [PATCH v9 04/10] namei: split out nd->dfd handling to dirfd_path_init

On Sun, Jul 07, 2019 at 12:57:31AM +1000, Aleksa Sarai wrote:

Previously, path_init's handling of *at(dfd, ...) was only done once, but with LOOKUP_BENEATH (and LOOKUP_IN_ROOT) we have to parse the initial nd->path at different times (before or after absolute path handling) depending on whether we have been asked to scope resolution within a root.

if (*s == '/') {

• set_root(nd);
  

• if (likely(!nd_jump_root(nd)))
  

• 	return s;
  

• return ERR_PTR(-ECHILD);
  

• if (likely(!nd->root.mnt))
  

• 	set_root(nd);
  

How can we get there with non-NULL nd->root.mnt, when LOOKUP_ROOT case has been already handled by that point?

• error = nd_jump_root(nd);
  

• if (unlikely(error))
  

• 	s = ERR_PTR(error);