On 2019-11-13, Al Viro viro@zeniv.linux.org.uk wrote:
Minor nit here - I'd split "move the conditional call of set_root() into nd_jump_root()" into a separate patch before that one. Makes for fewer distractions in this one. I'd probably fold "and be ready for errors other than -ECHILD" into the same preliminary patch.
Will do.
/* Not currently safe for scoped-lookups. */if (unlikely(nd->flags & LOOKUP_IS_SCOPED))return ERR_PTR(-EXDEV);Also a candidate for doing in nd_jump_link()...
@@ -1373,8 +1403,11 @@ static int follow_dotdot_rcu(struct nameidata *nd) struct inode *inode = nd->inode; while (1) {
if (path_equal(&nd->path, &nd->root))
if (path_equal(&nd->path, &nd->root)) {if (unlikely(nd->flags & LOOKUP_BENEATH))return -EXDEV;Umm... Are you sure it's not -ECHILD?
It wouldn't hurt to be -ECHILD -- though it's not clear to me how likely a success would be in REF-walk if the parent components didn't already trigger an unlazy_walk() in RCU-walk.
I guess that also means LOOKUP_NO_XDEV should trigger -ECHILD in follow_dotdot_rcu()?