[LU-15177] cs_update live batch update hung waiting for MDT recovery to complete

• Type: Bug
• Resolution: Unresolved
• Priority: Major
• Severity: 3
• Assignee: Alexander Zarochentsev
• Reporter: Alexander Zarochentsev

Description

Problem: MDT-MDT interop check prevents (single MDT) rolling update from 2.12.0.5-based -> 2.12.4.1-based Lustre because the versions are too far away from one another to complete inter-op recovery.

two similar code snippets found in ptlrpc_connect_interpret() and
target_handle_connect():

                        /*
                         * We do not support the MDT-MDT interoperations with
                         * different version MDT because of protocol changes.
                         */
                        if (unlikely(major != LUSTRE_MAJOR ||
                                     minor != LUSTRE_MINOR ||
                                     abs(patch - LUSTRE_PATCH) > 3)) {
                                LCONSOLE_WARN("%s (%u.%u.%u.%u) refused the connection from different version MDT (%d.%d.%d.%d) %s %s\n",
                                              target->obd_name, LUSTRE_MAJOR,
                                              LUSTRE_MINOR, LUSTRE_PATCH,
                                              LUSTRE_FIX, major, minor, patch,
                                              OBD_OCD_VERSION_FIX(data->ocd_version),
                                              libcfs_nid2str(req->rq_peer.nid),
                                              str);
                                GOTO(out, rc = -EPROTO);
                        }

looks the constant of "3" was chosen for some specific protocol changes in the past, but is it still needed ?

Issue Links

• is related to: LU-17217 Allow server to control/deny client connections