Re: [PATCH 1/3] ceph: handle InodeStat v8 versioned field in reply parsing

[Alex Markuze <amarkuze@redhat.com>]

v8 was added for case insensitive file systems, not relevant to Linux,
I can add a comment saying that.

On Mon, Dec 1, 2025 at 10:20 PM Viacheslav Dubeyko
<Slava.Dubeyko@ibm.com> wrote:
>
> On Thu, 2025-11-27 at 13:46 +0000, Alex Markuze wrote:
> > Add forward-compatible handling for the new versioned field introduced
> > in InodeStat v8. This patch only skips the field without using it,
> > preparing for future protocol extensions.
> >
> > The v8 encoding adds a versioned sub-structure that needs to be properly
> > decoded and skipped to maintain compatibility with newer MDS versions.
> >
> > Signed-off-by: Alex Markuze <amarkuze@redhat.com>
> > ---
> >  fs/ceph/mds_client.c | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
> >
> > diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> > index 1740047aef0f..32561fc701e5 100644
> > --- a/fs/ceph/mds_client.c
> > +++ b/fs/ceph/mds_client.c
> > @@ -231,6 +231,18 @@ static int parse_reply_info_in(void **p, void *end,
> >                                                     info->fscrypt_file_len, bad);
> >                       }
> >               }
> > +
> > +             /* struct_v 8 added a versioned field - skip it */
> > +             if (struct_v >= 8) {
> > +                     u8 v8_struct_v, v8_struct_compat;
> > +                     u32 v8_struct_len;
> > +
>
> Probably, we need to have warning here that, currently, this protocol is not
> supported yet.
>
> Thanks,
> Slava.
>
> > +                     ceph_decode_8_safe(p, end, v8_struct_v, bad);
> > +                     ceph_decode_8_safe(p, end, v8_struct_compat, bad);
> > +                     ceph_decode_32_safe(p, end, v8_struct_len, bad);
> > +                     ceph_decode_skip_n(p, end, v8_struct_len, bad);
> > +             }
> > +
> >               *p = end;
> >       } else {
> >               /* legacy (unversioned) struct */