Re: [PATCH v3 1/2] fs: add the ability for statmount() to report the fs_subtype

[Christian Brauner]

On Mon, Nov 11, 2024 at 08:28:07AM -0500, Jeff Layton wrote:
> On Mon, 2024-11-11 at 14:01 +0100, Miklos Szeredi wrote:
> > On Mon, 11 Nov 2024 at 12:28, Jeff Layton <jlayton@xxxxxxxxxx> wrote:
> > 
> > > As far as I can tell, the existing cases in statmount_string() either
> > > always emit a string or an error code. If a string isn't emitted, then
> > > the two EOVERFLOW cases and the EAGAIN case can't happen, so I don't
> > > think this will result in any change in behavior for the existing code.
> > 
> > Both mnt_point and mnt_opts can be empty.
> > 
> 
> Ok, so currently if they are, the flag gets set and there is no
> string?  If so, then you're correct and this is a behavior change. The
> question is -- is it a desirable one? The interface is new enough that
> I think we have the luxury of changing this now (and establishing a
> future standard).
> 
> Personally, I think that's how it ought to work. When there is no
> string present, we ought not set the flag in the return mask. Does
> anyone prefer it the other way?

It's a change we can certainly do. I see no reason not to try it.