Re: v7.0-rc1, name_to_handle_at(..., AT_EMPTY_PATH)

[Al Viro <viro@zeniv.linux.org.uk>]

On Fri, Feb 27, 2026 at 07:44:58PM +0900, J. R. Okajima wrote:
> Hello Al Viro,
> 
> By the commit in v7.0-rc1,
> 	154ef7dce6a4d 2026-01-16 name_to_handle_at(): use CLASS(filename_uflags)
> name_to_handle_at(2) stopped handling AT_EMPTY_PATH, and an application
> which issues
> 	name_to_handle_at(fd, "", handle, &mnt_id, AT_EMPTY_PATH);
> started failing.
> 
> It is due to the commit dropped setting LOOKUP_EMPTY to lookup_flags in
> name_to_handle_at(2).

Huh?
	CLASS(filename_uflags, filename)(name, flag);
*does* accept empty path if flag & AT_EMPTY_PATH is non-zero.

So if you are really observing such failures, something else must've gone
wrong.  Details, please.

This
struct filename *getname_uflags(const char __user *filename, int uflags)
{
        int flags = (uflags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0;

	return getname_flags(filename, flags);
}
is where AT_EMPTY_PATH is handled; could you check the arguuments it's getting
in your reproducer and argument passed to getname_flags()?