Ceph » CephFS

This code needs a rework to support versioning, because the outer message encoding in e.g. handle_discover_reply operates on a "while(!p.end())" basis. These structures need to be lists of bufferlists instead, where each bufferlist is something versioned.

Oh right, so as Zheng reminds me in his patch for #12105, we do have the CEPH_MDS_PROTOCOL value for these changes.

I don't know... it still feels like it would be better to not rely on a global protocol version for all these fields. Anyone else have feelings?

yes, it's better to not rely on CEPH_MDS_PROTOCOL. (CEPH_MDS_PROTOCOL will make the rework easier)

Mmmm. For over-the-wire encodings that don't go to disk, it's only about whether cross-version daemons can communicate or not.

I think it might be worth maintaining that communication as much as possible, but I'm not certain where the best place to put in the versioning is — for instance we might want to do a per-message or per-session encoding version instead that we keep track of instead?

I'm working on this, please assign this to me

have added the support for MDentryLink and MDentryUnlink,
next step is CInode::encode_lock_state/CInode::decode_lock_state,
there are two big switch, need to break down to small encode/decode functions for each state.