[LU-15610] ofd can skip object version setting in case of error

• Status: Open
• Project: Lustre
• Type: Bug
• Priority: Minor
• Reporter: Alex Zhuravlev
• Assignee: WC Triage
• Resolution: Unresolved
• Labels: flr-improvement
• Severity: 3

Description

tgt_last_rcvd_update() skips version setting if result of transaction is not 0:

        if (th->th_result == 0 && obj != NULL) {
                struct dt_object *dto = dt_object_locate(obj, th->th_dev);
                dt_version_set(env, dto, tti->tti_transno, th);
        }

in turn, ofd_getattr_hdl() uses this version as "data version" for the client:

                /* Store object version in reply */
                curr_version = dt_version_get(tsi->tsi_env,
                                              ofd_object_child(fo));
                if ((__s64)curr_version != -EOPNOTSUPP) {
                        repbody->oa.o_valid |= OBD_MD_FLDATAVERSION;
                        repbody->oa.o_data_version = curr_version;
                }

the problem is that OSD can do few separate IOs within a single transaction and returns the result of the last one which can be non-zero due to an IO failure. IOW, some IOs can proceeed and change on-disk data, but the version won't get updated.

and then lfs mirror extend/resync won't notice if such a problem happens during data resyncing.