LU-8900 snapshot: simulate readonly device

[fs/lustre-release.git] / lustre / mgc / mgc_request.c

diff --git a/lustre/mgc/mgc_request.c b/lustre/mgc/mgc_request.c
index 12a8751..119c0df 100644 (file)
--- a/lustre/mgc/mgc_request.c
+++ b/lustre/mgc/mgc_request.c
@@ -1930,7 +1930,7 @@ static int mgc_process_cfg_log(struct obd_device *mgc,
            cli->cl_mgc_configs_dir != NULL &&
            lu2dt_dev(cli->cl_mgc_configs_dir->do_lu.lo_dev) ==
            lsi->lsi_dt_dev) {
-               if (!local_only)
+               if (!local_only && !lsi->lsi_dt_dev->dd_rdonly)
                        /* Only try to copy log if we have the lock. */
                        rc = mgc_llog_local_copy(env, mgc, ctxt, lctxt,
                                                 cld->cld_logname);
@@ -1958,11 +1958,24 @@ static int mgc_process_cfg_log(struct obd_device *mgc,
                        GOTO(out_pop, rc = -EIO);
        }
 
-       /* logname and instance info should be the same, so use our
-        * copy of the instance for the update.  The cfg_last_idx will
-        * be updated here. */
-       rc = class_config_parse_llog(env, ctxt, cld->cld_logname,
-                                    &cld->cld_cfg);
+       rc = -EAGAIN;
+       if (lsi && IS_SERVER(lsi) && !IS_MGS(lsi) &&
+           lsi->lsi_dt_dev->dd_rdonly) {
+               struct llog_ctxt *rctxt;
+
+               /* Under readonly mode, we may have no local copy or local
+                * copy is incomplete, so try to use remote llog firstly. */
+               rctxt = llog_get_context(mgc, LLOG_CONFIG_REPL_CTXT);
+               LASSERT(rctxt);
+
+               rc = class_config_parse_llog(env, rctxt, cld->cld_logname,
+                                            &cld->cld_cfg);
+               llog_ctxt_put(rctxt);
+       }
+
+       if (rc && rc != -ENOENT)
+               rc = class_config_parse_llog(env, ctxt, cld->cld_logname,
+                                            &cld->cld_cfg);
 
        /*
         * update settings on existing OBDs. doing it inside