Re: [PATCH 1/2] mount: add OPEN_TREE_NAMESPACE

[Florian Weimer <fweimer@redhat.com>]

* Christian Brauner:

> On Tue, Feb 24, 2026 at 02:30:37PM +0100, Florian Weimer wrote:
>> * Christian Brauner:
>> 
>> > On Tue, Feb 24, 2026 at 12:23:33PM +0100, Florian Weimer wrote:
>> >> * Christian Brauner:
>> >> 
>> >> > diff --git a/include/uapi/linux/mount.h b/include/uapi/linux/mount.h
>> >> > index 5d3f8c9e3a62..acbc22241c9c 100644
>> >> > --- a/include/uapi/linux/mount.h
>> >> > +++ b/include/uapi/linux/mount.h
>> >> > @@ -61,7 +61,8 @@
>> >> >  /*
>> >> >   * open_tree() flags.
>> >> >   */
>> >> > -#define OPEN_TREE_CLONE		1		/* Clone the target tree and attach the clone */
>> >> > +#define OPEN_TREE_CLONE		(1 << 0)	/* Clone the target tree and attach the clone */
>> >> 
>> >> This change causes pointless -Werror=undef errors in projects that have
>> >> settled on the old definition.
>> >> 
>> >> Reported here:
>> >> 
>> >>   Bug 33921 - Building with Linux-7.0-rc1 errors on OPEN_TREE_CLONE
>> >>   <https://sourceware.org/bugzilla/show_bug.cgi?id=33921>
>> >
>> > Send a patch to change it back, please.
>> > Otherwise it might take a few days until I get around to it.
>> 
>> Rudi, could you post a patch?
>
> I'm a bit confused though and not super happy that you're basically
> asking us to be so constrained that we aren't even allowed to change 1
> to 1 - just syntactically different.

I'm not happy about it, either.  But it has happened before, for the
RENAME_* constants I believe.

We are already including <linux/mount.h> from <sys/mount.h>, so we can
work around this reliably on the glibc side, regardless of header
inclusion order.

Thanks,
Florian