Re: file handle in statx (was: Re: How to cope with subvolumes and snapshots on muti-user systems?)

David Howells
2023-12-12T09:46:58Z

Christian Brauner <brauner@kernel.org> wrote:

> > There is a upcoming potential problem where even the 64-bit field I placed
> > in statx() may be insufficient. The Auristor AFS server, for example, has
> > a 96-bit vnode ID, but I can't properly represent this in stx_ino.
> > Currently, I
>
> Is that vnode ID akin to a volume? Because if so you could just
> piggy-back on a subvolume id field in statx() and expose it there.

No. The volume ID is the ID of the volume. The vnode is the equivalent of an
inode.

> > just truncate the value to fit and hope that the discarded part will be all
> > zero, but that's not really a good thing to do - especially when stx_ino is
> > used programmatically to check for hardlinks.
> >
> > Would it be better to add an 'stx_ino_2' field and corresponding flag?
>
> Would this be meaningfully different from using a file handle?

There's also the matter of presenting the "inode number" to the user - "ls -i"
for example.

David