On Sat, Aug 29, 2020 at 07:51:47PM +0200, Miklos Szeredi wrote: > On Sat, Aug 29, 2020 at 6:14 PM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote: > > > > On Sat, Aug 29, 2020 at 05:07:17PM +0100, Matthew Wilcox wrote: > > > > > > > The fact that ADS inodes would not be in the dentry cache and hence > > > > not visible to pathwalks at all then means that all of the issues > > > > such as mounting over them, chroot, etc don't exist in the first > > > > place... > > > > > > Wait, you've now switched from "this is dentry cache infrastructure" > > > to "it should not be in the dentry cache". So I don't understand what > > > you're arguing for. > > > > Bloody wonderful, that. So now we have struct file instances with no dentry > > associated with them? Which would have to be taken into account all over > > the place... > > It could have a temporary dentry allocated for the lifetime of the > file and dropped on last dput. I.e. there's a dentry, but no cache. > Yeah, yeah, d_path() issues, however that one will have to be special > cased anyway. d_path() is the least of the problems, actually. Directory tree structure on those, OTOH, is a serious problem. If you want to have getdents(2) on that shite, you want an opened descriptor that looks like a directory. And _that_ opens a large can of worms. Because now you have fchdir(2) to cope with, lookups going through /proc/self/fd/<n>/..., etc., etc. Al, fully expecting "we'll special-case our way out of everything - how hard could that be?" in response...
