On Mon, Jul 04, 2022 at 01:51:16PM -0700, Linus Torvalds wrote: > On Mon, Jul 4, 2022 at 1:46 PM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > > > Why is that a problem? It could have been moved to another parent, > > but so it could after we'd crossed to the mounted and we wouldn't have > > noticed (or cared). > > Yeah, see my other email. > > I agree that it might be a "we don't actually care" situation, where > all we care about that the name was valid at one point (when we picked > up that sequence point). So maybe we don't care about closing it. > > But even if so, I think it might warrant a comment, because I still > feel like we're basically "throwing away" our previous sequence point > information without ever checking it. > > Maybe all we ever care about is basically "this sequence point > protects the dentry inode pointer for the next lookup", and when it > comes to mount points that ends up being immaterial. There is a problem, actually, but it's in a different place... OK, let me try to write something resembling a formal proof and see what falls out.