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LU-14090 mgs: no local logs flag
[fs/lustre-release.git] / lustre / mgc / mgc_request.c
index 6b51d52..ecce505 100644 (file)
  *
  * You should have received a copy of the GNU General Public License
  * version 2 along with this program; If not, see
- * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
+ * http://www.gnu.org/licenses/gpl-2.0.html
  *
  * GPL HEADER END
  */
@@ -27,7 +23,7 @@
  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2011, 2015, Intel Corporation.
+ * Copyright (c) 2011, 2017, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
@@ -43,6 +39,7 @@
 
 #include <linux/module.h>
 #include <linux/kthread.h>
+#include <linux/random.h>
 
 #include <dt_object.h>
 #include <lprocfs_status.h>
@@ -52,6 +49,7 @@
 #include <lustre_nodemap.h>
 #include <lustre_swab.h>
 #include <obd_class.h>
+#include <lustre_barrier.h>
 
 #include "mgc_internal.h"
 
@@ -82,6 +80,7 @@ static int mgc_name2resid(char *name, int len, struct ldlm_res_id *res_id,
        case CONFIG_T_RECOVER:
        case CONFIG_T_PARAMS:
        case CONFIG_T_NODEMAP:
+       case CONFIG_T_BARRIER:
                resname = type;
                break;
         default:
@@ -101,8 +100,7 @@ int mgc_fsname2resid(char *fsname, struct ldlm_res_id *res_id, int type)
 }
 EXPORT_SYMBOL(mgc_fsname2resid);
 
-static int mgc_logname2resid(char *logname, struct ldlm_res_id *res_id,
-                            int type)
+int mgc_logname2resid(char *logname, struct ldlm_res_id *res_id, int type)
 {
        char *name_end;
        int len;
@@ -117,17 +115,18 @@ static int mgc_logname2resid(char *logname, struct ldlm_res_id *res_id,
                len = name_end - logname;
        return mgc_name2resid(logname, len, res_id, type);
 }
+EXPORT_SYMBOL(mgc_logname2resid);
 
 /********************** config llog list **********************/
-static struct list_head config_llog_list = LIST_HEAD_INIT(config_llog_list);
-static DEFINE_SPINLOCK(config_list_lock);
+static LIST_HEAD(config_llog_list);
+static DEFINE_SPINLOCK(config_list_lock);      /* protects config_llog_list */
 
 /* Take a reference to a config log */
 static int config_log_get(struct config_llog_data *cld)
 {
        ENTRY;
        atomic_inc(&cld->cld_refcount);
-       CDEBUG(D_INFO, "log %s refs %d\n", cld->cld_logname,
+       CDEBUG(D_INFO, "log %s (%p) refs %d\n", cld->cld_logname, cld,
                atomic_read(&cld->cld_refcount));
        RETURN(0);
 }
@@ -138,7 +137,10 @@ static void config_log_put(struct config_llog_data *cld)
 {
        ENTRY;
 
-       CDEBUG(D_INFO, "log %s refs %d\n", cld->cld_logname,
+       if (unlikely(!cld))
+               RETURN_EXIT;
+
+       CDEBUG(D_INFO, "log %s(%p) refs %d\n", cld->cld_logname, cld,
                atomic_read(&cld->cld_refcount));
        LASSERT(atomic_read(&cld->cld_refcount) > 0);
 
@@ -149,16 +151,15 @@ static void config_log_put(struct config_llog_data *cld)
 
                CDEBUG(D_MGC, "dropping config log %s\n", cld->cld_logname);
 
-               if (cld->cld_recover)
-                       config_log_put(cld->cld_recover);
-               if (cld->cld_sptlrpc)
-                       config_log_put(cld->cld_sptlrpc);
-               if (cld->cld_params)
-                       config_log_put(cld->cld_params);
-               if (cld->cld_nodemap)
-                       config_log_put(cld->cld_nodemap);
-               if (cld_is_sptlrpc(cld))
+               config_log_put(cld->cld_barrier);
+               config_log_put(cld->cld_recover);
+               config_log_put(cld->cld_params);
+               config_log_put(cld->cld_nodemap);
+               config_log_put(cld->cld_sptlrpc);
+               if (cld_is_sptlrpc(cld)) {
+                       cld->cld_stopping = 1;
                        sptlrpc_conf_log_stop(cld->cld_logname);
+               }
 
                class_export_put(cld->cld_mgcexp);
                OBD_FREE(cld, sizeof(*cld) + strlen(cld->cld_logname) + 1);
@@ -172,30 +173,27 @@ static
 struct config_llog_data *config_log_find(char *logname,
                                          struct config_llog_instance *cfg)
 {
-        struct config_llog_data *cld;
-        struct config_llog_data *found = NULL;
-        void *                   instance;
-        ENTRY;
+       struct config_llog_data *cld;
+       struct config_llog_data *found = NULL;
+       unsigned long cfg_instance;
 
-        LASSERT(logname != NULL);
+       ENTRY;
+       LASSERT(logname != NULL);
 
-        instance = cfg ? cfg->cfg_instance : NULL;
+       cfg_instance = cfg ? cfg->cfg_instance : 0;
        spin_lock(&config_list_lock);
        list_for_each_entry(cld, &config_llog_list, cld_list_chain) {
-                /* check if instance equals */
-                if (instance != cld->cld_cfg.cfg_instance)
-                        continue;
+               /* check if cfg_instance is the one we want */
+               if (cfg_instance != cld->cld_cfg.cfg_instance)
+                       continue;
 
                /* instance may be NULL, should check name */
                if (strcmp(logname, cld->cld_logname) == 0) {
                        found = cld;
+                       config_log_get(found);
                        break;
                }
        }
-       if (found) {
-               atomic_inc(&found->cld_refcount);
-               LASSERT(found->cld_stopping == 0 || cld_is_sptlrpc(found) == 0);
-       }
        spin_unlock(&config_list_lock);
        RETURN(found);
 }
@@ -212,13 +210,19 @@ struct config_llog_data *do_config_log_add(struct obd_device *obd,
 
        ENTRY;
 
-       CDEBUG(D_MGC, "do adding config log %s:%p\n", logname,
-              cfg ? cfg->cfg_instance : NULL);
+       CDEBUG(D_MGC, "do adding config log %s-%016lx\n", logname,
+              cfg ? cfg->cfg_instance : 0);
 
        OBD_ALLOC(cld, sizeof(*cld) + strlen(logname) + 1);
        if (!cld)
                RETURN(ERR_PTR(-ENOMEM));
 
+       rc = mgc_logname2resid(logname, &cld->cld_resid, type);
+       if (rc) {
+               OBD_FREE(cld, sizeof(*cld) + strlen(cld->cld_logname) + 1);
+               RETURN(ERR_PTR(rc));
+       }
+
        strcpy(cld->cld_logname, logname);
        if (cfg)
                cld->cld_cfg = *cfg;
@@ -234,23 +238,14 @@ struct config_llog_data *do_config_log_add(struct obd_device *obd,
        /* Keep the mgc around until we are done */
        cld->cld_mgcexp = class_export_get(obd->obd_self_export);
 
-       if (cld_is_sptlrpc(cld)) {
+       if (cld_is_sptlrpc(cld))
                sptlrpc_conf_log_start(logname);
-               cld->cld_cfg.cfg_obdname = obd->obd_name;
-       }
-
-       rc = mgc_logname2resid(logname, &cld->cld_resid, type);
 
        spin_lock(&config_list_lock);
        list_add(&cld->cld_list_chain, &config_llog_list);
        spin_unlock(&config_list_lock);
 
-       if (rc) {
-               config_log_put(cld);
-               RETURN(ERR_PTR(rc));
-       }
-
-       if (cld_is_sptlrpc(cld) || cld_is_nodemap(cld)) {
+       if (cld_is_sptlrpc(cld) || cld_is_nodemap(cld) || cld_is_barrier(cld)) {
                rc = mgc_process_log(obd, cld);
                if (rc && rc != -ENOENT)
                        CERROR("%s: failed processing log, type %d: rc = %d\n",
@@ -261,51 +256,55 @@ struct config_llog_data *do_config_log_add(struct obd_device *obd,
 }
 
 static struct config_llog_data *config_recover_log_add(struct obd_device *obd,
-        char *fsname,
-        struct config_llog_instance *cfg,
-        struct super_block *sb)
+                                       char *fsname,
+                                       struct config_llog_instance *cfg,
+                                       struct super_block *sb)
 {
-        struct config_llog_instance lcfg = *cfg;
-        struct lustre_sb_info *lsi = s2lsi(sb);
-        struct config_llog_data *cld;
-        char logname[32];
+       struct config_llog_instance lcfg = *cfg;
+       struct lustre_sb_info *lsi = s2lsi(sb);
+       struct config_llog_data *cld;
+       char logname[32];
 
        if (IS_OST(lsi))
-                return NULL;
+               return NULL;
 
        /* for osp-on-ost, see lustre_start_osp() */
        if (IS_MDT(lsi) && lcfg.cfg_instance)
                return NULL;
 
-        /* we have to use different llog for clients and mdts for cmd
-         * where only clients are notified if one of cmd server restarts */
-        LASSERT(strlen(fsname) < sizeof(logname) / 2);
-        strcpy(logname, fsname);
+       /* We have to use different llog for clients and MDTs for DNE,
+        * where only clients are notified if one of DNE server restarts.
+        */
+       LASSERT(strlen(fsname) < sizeof(logname) / 2);
+       strncpy(logname, fsname, sizeof(logname));
        if (IS_SERVER(lsi)) { /* mdt */
-                LASSERT(lcfg.cfg_instance == NULL);
-                lcfg.cfg_instance = sb;
-                strcat(logname, "-mdtir");
-        } else {
-                LASSERT(lcfg.cfg_instance != NULL);
-                strcat(logname, "-cliir");
-        }
+               LASSERT(lcfg.cfg_instance == 0);
+               lcfg.cfg_instance = ll_get_cfg_instance(sb);
+               strncat(logname, "-mdtir", sizeof(logname));
+       } else {
+               LASSERT(lcfg.cfg_instance != 0);
+               strncat(logname, "-cliir", sizeof(logname));
+       }
 
-        cld = do_config_log_add(obd, logname, CONFIG_T_RECOVER, &lcfg, sb);
-        return cld;
+       cld = do_config_log_add(obd, logname, CONFIG_T_RECOVER, &lcfg, sb);
+       return cld;
 }
 
-static struct config_llog_data *config_params_log_add(struct obd_device *obd,
-       struct config_llog_instance *cfg, struct super_block *sb)
+static struct config_llog_data *config_log_find_or_add(struct obd_device *obd,
+                               char *logname, struct super_block *sb, int type,
+                               struct config_llog_instance *cfg)
 {
-       struct config_llog_instance     lcfg = *cfg;
-       struct config_llog_data         *cld;
+       struct config_llog_instance lcfg = *cfg;
+       struct config_llog_data *cld;
 
-       lcfg.cfg_instance = sb;
+       /* Note class_config_llog_handler() depends on getting "obd" back */
+       lcfg.cfg_instance = sb ? ll_get_cfg_instance(sb) : (unsigned long)obd;
 
-       cld = do_config_log_add(obd, PARAMS_FILENAME, CONFIG_T_PARAMS,
-                               &lcfg, sb);
+       cld = config_log_find(logname, &lcfg);
+       if (unlikely(cld != NULL))
+               return cld;
 
-       return cld;
+       return do_config_log_add(obd, logname, type, &lcfg, sb);
 }
 
 /** Add this log to the list of active logs watched by an MGC.
@@ -313,21 +312,24 @@ static struct config_llog_data *config_params_log_add(struct obd_device *obd,
  * We have one active log per "mount" - client instance or servername.
  * Each instance may be at a different point in the log.
  */
-static int config_log_add(struct obd_device *obd, char *logname,
-                         struct config_llog_instance *cfg,
-                         struct super_block *sb)
+static struct config_llog_data *
+config_log_add(struct obd_device *obd, char *logname,
+              struct config_llog_instance *cfg, struct super_block *sb)
 {
-       struct lustre_sb_info   *lsi = s2lsi(sb);
-       struct config_llog_data *cld;
-       struct config_llog_data *sptlrpc_cld;
-       struct config_llog_data *params_cld;
-       struct config_llog_data *nodemap_cld;
-       char                    seclogname[32];
-       char                    *ptr;
-       int                     rc;
+       struct lustre_sb_info *lsi = s2lsi(sb);
+       struct config_llog_data *cld = NULL;
+       struct config_llog_data *sptlrpc_cld = NULL;
+       struct config_llog_data *params_cld = NULL;
+       struct config_llog_data *nodemap_cld = NULL;
+       struct config_llog_data *barrier_cld = NULL;
+       char seclogname[32];
+       char *ptr;
+       int rc;
+       bool locked = false;
        ENTRY;
 
-       CDEBUG(D_MGC, "adding config log %s:%p\n", logname, cfg->cfg_instance);
+       CDEBUG(D_MGC, "add config log %s-%016lx\n", logname,
+              cfg->cfg_instance);
 
        /*
         * for each regular log, the depended sptlrpc log name is
@@ -336,26 +338,26 @@ static int config_log_add(struct obd_device *obd, char *logname,
        ptr = strrchr(logname, '-');
        if (ptr == NULL || ptr - logname > 8) {
                CERROR("logname %s is too long\n", logname);
-               RETURN(-EINVAL);
+               RETURN(ERR_PTR(-EINVAL));
        }
 
        memcpy(seclogname, logname, ptr - logname);
        strcpy(seclogname + (ptr - logname), "-sptlrpc");
 
-       sptlrpc_cld = config_log_find(seclogname, NULL);
-       if (sptlrpc_cld == NULL) {
-               sptlrpc_cld = do_config_log_add(obd, seclogname,
-                                               CONFIG_T_SPTLRPC, NULL, NULL);
+       if (cfg->cfg_sub_clds & CONFIG_SUB_SPTLRPC) {
+               sptlrpc_cld = config_log_find_or_add(obd, seclogname, NULL,
+                                                    CONFIG_T_SPTLRPC, cfg);
                if (IS_ERR(sptlrpc_cld)) {
-                       CERROR("can't create sptlrpc log: %s\n", seclogname);
-                       GOTO(out, rc = PTR_ERR(sptlrpc_cld));
+                       CERROR("%s: can't create sptlrpc log %s: rc = %ld\n",
+                              obd->obd_name, seclogname, PTR_ERR(sptlrpc_cld));
+                       RETURN(sptlrpc_cld);
                }
        }
 
-       nodemap_cld = config_log_find(LUSTRE_NODEMAP_NAME, NULL);
-       if (!nodemap_cld && IS_SERVER(lsi) && !IS_MGS(lsi)) {
-               nodemap_cld = do_config_log_add(obd, LUSTRE_NODEMAP_NAME,
-                                               CONFIG_T_NODEMAP, NULL, NULL);
+       if (!IS_MGS(lsi) && cfg->cfg_sub_clds & CONFIG_SUB_NODEMAP) {
+               nodemap_cld = config_log_find_or_add(obd, LUSTRE_NODEMAP_NAME,
+                                                    NULL, CONFIG_T_NODEMAP,
+                                                    cfg);
                if (IS_ERR(nodemap_cld)) {
                        rc = PTR_ERR(nodemap_cld);
                        CERROR("%s: cannot create nodemap log: rc = %d\n",
@@ -364,63 +366,113 @@ static int config_log_add(struct obd_device *obd, char *logname,
                }
        }
 
-       params_cld = config_params_log_add(obd, cfg, sb);
-       if (IS_ERR(params_cld)) {
-               rc = PTR_ERR(params_cld);
-               CERROR("%s: can't create params log: rc = %d\n",
-                      obd->obd_name, rc);
-               GOTO(out_nodemap, rc);
+       if (cfg->cfg_sub_clds & CONFIG_SUB_PARAMS) {
+               params_cld = config_log_find_or_add(obd, PARAMS_FILENAME, sb,
+                                                   CONFIG_T_PARAMS, cfg);
+               if (IS_ERR(params_cld)) {
+                       rc = PTR_ERR(params_cld);
+                       CERROR("%s: can't create params log: rc = %d\n",
+                              obd->obd_name, rc);
+                       GOTO(out_nodemap, rc);
+               }
+       }
+
+       if (IS_MDT(s2lsi(sb)) && cfg->cfg_sub_clds & CONFIG_SUB_BARRIER) {
+               snprintf(seclogname + (ptr - logname), sizeof(seclogname) - 1,
+                        "-%s", BARRIER_FILENAME);
+               barrier_cld = config_log_find_or_add(obd, seclogname, sb,
+                                                    CONFIG_T_BARRIER, cfg);
+               if (IS_ERR(barrier_cld)) {
+                       rc = PTR_ERR(barrier_cld);
+                       CERROR("%s: can't create barrier log: rc = %d\n",
+                              obd->obd_name, rc);
+                       GOTO(out_params, rc);
+               }
        }
 
        cld = do_config_log_add(obd, logname, CONFIG_T_CONFIG, cfg, sb);
        if (IS_ERR(cld)) {
-               CERROR("can't create log: %s\n", logname);
-               GOTO(out_params, rc = PTR_ERR(cld));
+               rc = PTR_ERR(cld);
+               CERROR("%s: can't create log: rc = %d\n",
+                      obd->obd_name, rc);
+               GOTO(out_barrier, rc = PTR_ERR(cld));
        }
 
        LASSERT(lsi->lsi_lmd);
-       if (!(lsi->lsi_lmd->lmd_flags & LMD_FLG_NOIR)) {
+       if (!(lsi->lsi_lmd->lmd_flags & LMD_FLG_NOIR) &&
+           cfg->cfg_sub_clds & CONFIG_SUB_RECOVER) {
                struct config_llog_data *recover_cld;
+
                ptr = strrchr(seclogname, '-');
                if (ptr != NULL) {
                        *ptr = 0;
-               }
-               else {
+               } else {
                        CERROR("%s: sptlrpc log name not correct, %s: "
                               "rc = %d\n", obd->obd_name, seclogname, -EINVAL);
-                       config_log_put(cld);
-                       RETURN(-EINVAL);
+                       GOTO(out_cld, rc = -EINVAL);
                }
+
                recover_cld = config_recover_log_add(obd, seclogname, cfg, sb);
-               if (IS_ERR(recover_cld))
-                       GOTO(out_cld, rc = PTR_ERR(recover_cld));
+               if (IS_ERR(recover_cld)) {
+                       rc = PTR_ERR(recover_cld);
+                       CERROR("%s: can't create recover log: rc = %d\n",
+                              obd->obd_name, rc);
+                       GOTO(out_cld, rc);
+               }
+
+               mutex_lock(&cld->cld_lock);
+               locked = true;
                cld->cld_recover = recover_cld;
        }
 
-       cld->cld_sptlrpc = sptlrpc_cld;
+       if (!locked)
+               mutex_lock(&cld->cld_lock);
        cld->cld_params = params_cld;
+       cld->cld_barrier = barrier_cld;
        cld->cld_nodemap = nodemap_cld;
+       cld->cld_sptlrpc = sptlrpc_cld;
+       mutex_unlock(&cld->cld_lock);
 
-       RETURN(0);
+       RETURN(cld);
 
 out_cld:
        config_log_put(cld);
-
+out_barrier:
+       config_log_put(barrier_cld);
 out_params:
        config_log_put(params_cld);
-
 out_nodemap:
        config_log_put(nodemap_cld);
-
 out_sptlrpc:
        config_log_put(sptlrpc_cld);
 
-out:
-       return rc;
+       return ERR_PTR(rc);
 }
 
 DEFINE_MUTEX(llog_process_lock);
 
+static inline void config_mark_cld_stop_nolock(struct config_llog_data *cld)
+{
+       ENTRY;
+
+       spin_lock(&config_list_lock);
+       cld->cld_stopping = 1;
+       spin_unlock(&config_list_lock);
+
+       CDEBUG(D_INFO, "lockh %#llx\n", cld->cld_lockh.cookie);
+       if (!ldlm_lock_addref_try(&cld->cld_lockh, LCK_CR))
+               ldlm_lock_decref_and_cancel(&cld->cld_lockh, LCK_CR);
+}
+
+static inline void config_mark_cld_stop(struct config_llog_data *cld)
+{
+       if (cld) {
+               mutex_lock(&cld->cld_lock);
+               config_mark_cld_stop_nolock(cld);
+               mutex_unlock(&cld->cld_lock);
+       }
+}
+
 /** Stop watching for updates on this log.
  */
 static int config_log_end(char *logname, struct config_llog_instance *cfg)
@@ -430,6 +482,7 @@ static int config_log_end(char *logname, struct config_llog_instance *cfg)
        struct config_llog_data *cld_params = NULL;
        struct config_llog_data *cld_recover = NULL;
        struct config_llog_data *cld_nodemap = NULL;
+       struct config_llog_data *cld_barrier = NULL;
        int rc = 0;
 
        ENTRY;
@@ -453,41 +506,32 @@ static int config_log_end(char *logname, struct config_llog_instance *cfg)
                RETURN(rc);
        }
 
-       cld->cld_stopping = 1;
-
        cld_recover = cld->cld_recover;
        cld->cld_recover = NULL;
-       mutex_unlock(&cld->cld_lock);
-
-       if (cld_recover) {
-               mutex_lock(&cld_recover->cld_lock);
-               cld_recover->cld_stopping = 1;
-               mutex_unlock(&cld_recover->cld_lock);
-               config_log_put(cld_recover);
-       }
-
-       spin_lock(&config_list_lock);
-       cld_sptlrpc = cld->cld_sptlrpc;
-       cld->cld_sptlrpc = NULL;
        cld_params = cld->cld_params;
        cld->cld_params = NULL;
        cld_nodemap = cld->cld_nodemap;
        cld->cld_nodemap = NULL;
-       spin_unlock(&config_list_lock);
-
-       if (cld_sptlrpc)
-               config_log_put(cld_sptlrpc);
+       cld_barrier = cld->cld_barrier;
+       cld->cld_barrier = NULL;
+       cld_sptlrpc = cld->cld_sptlrpc;
+       cld->cld_sptlrpc = NULL;
 
-       if (cld_params) {
-               mutex_lock(&cld_params->cld_lock);
-               cld_params->cld_stopping = 1;
-               mutex_unlock(&cld_params->cld_lock);
-               config_log_put(cld_params);
-       }
+       config_mark_cld_stop_nolock(cld);
+       mutex_unlock(&cld->cld_lock);
 
+       config_mark_cld_stop(cld_recover);
+       config_log_put(cld_recover);
+       config_mark_cld_stop(cld_params);
+       config_log_put(cld_params);
+       config_mark_cld_stop(cld_barrier);
+       config_log_put(cld_barrier);
+       /* don't explicitly set cld_stopping on sptlrpc lock here, as other
+        * targets may be active, it will be done in config_log_put if necessary
+        */
+       config_log_put(cld_sptlrpc);
        /* don't set cld_stopping on nm lock as other targets may be active */
-       if (cld_nodemap)
-               config_log_put(cld_nodemap);
+       config_log_put(cld_nodemap);
 
        /* drop the ref from the find */
        config_log_put(cld);
@@ -499,22 +543,26 @@ static int config_log_end(char *logname, struct config_llog_instance *cfg)
        RETURN(rc);
 }
 
-#ifdef CONFIG_PROC_FS
 int lprocfs_mgc_rd_ir_state(struct seq_file *m, void *data)
 {
        struct obd_device       *obd = data;
        struct obd_import       *imp;
        struct obd_connect_data *ocd;
        struct config_llog_data *cld;
+       int rc = 0;
+
        ENTRY;
+       LASSERT(obd);
+       with_imp_locked(obd, imp, rc) {
+               ocd = &imp->imp_connect_data;
 
-       LASSERT(obd != NULL);
-       LPROCFS_CLIMP_CHECK(obd);
-       imp = obd->u.cli.cl_import;
-       ocd = &imp->imp_connect_data;
+               seq_printf(m, "imperative_recovery: %s\n",
+                          OCD_HAS_FLAG(ocd, IMP_RECOV) ?
+                          "ENABLED" : "DISABLED");
+       }
+       if (rc)
+               RETURN(rc);
 
-       seq_printf(m, "imperative_recovery: %s\n",
-                  OCD_HAS_FLAG(ocd, IMP_RECOV) ? "ENABLED" : "DISABLED");
        seq_printf(m, "client_state:\n");
 
        spin_lock(&config_list_lock);
@@ -527,10 +575,8 @@ int lprocfs_mgc_rd_ir_state(struct seq_file *m, void *data)
        }
        spin_unlock(&config_list_lock);
 
-       LPROCFS_CLIMP_EXIT(obd);
        RETURN(0);
 }
-#endif
 
 /* reenqueue any lost locks */
 #define RQ_RUNNING     0x1
@@ -576,7 +622,7 @@ static void do_requeue(struct config_llog_data *cld)
  * in order to not flood the MGS.
  */
 #define MGC_TIMEOUT_MIN_SECONDS   5
-#define MGC_TIMEOUT_RAND_CENTISEC 0x1ff /* ~500 */
+#define MGC_TIMEOUT_RAND_CENTISEC 500
 
 static int mgc_requeue_thread(void *data)
 {
@@ -589,11 +635,9 @@ static int mgc_requeue_thread(void *data)
        /* Keep trying failed locks periodically */
        spin_lock(&config_list_lock);
        rq_state |= RQ_RUNNING;
-       while (1) {
-               struct l_wait_info lwi;
+       while (!(rq_state & RQ_STOP)) {
                struct config_llog_data *cld, *cld_prev;
-               int rand = cfs_rand() & MGC_TIMEOUT_RAND_CENTISEC;
-               int stopped = !!(rq_state & RQ_STOP);
+               int rand = prandom_u32_max(MGC_TIMEOUT_RAND_CENTISEC);
                int to;
 
                /* Any new or requeued lostlocks will change the state */
@@ -606,65 +650,57 @@ static int mgc_requeue_thread(void *data)
                }
 
                /* Always wait a few seconds to allow the server who
-                  caused the lock revocation to finish its setup, plus some
-                  random so everyone doesn't try to reconnect at once. */
-               to = msecs_to_jiffies(MGC_TIMEOUT_MIN_SECONDS * MSEC_PER_SEC);
+                * caused the lock revocation to finish its setup, plus some
+                * random so everyone doesn't try to reconnect at once.
+                */
+               to = cfs_time_seconds(MGC_TIMEOUT_MIN_SECONDS * 100 + rand);
                /* rand is centi-seconds */
-               to += msecs_to_jiffies(rand * MSEC_PER_SEC / 100);
-               lwi = LWI_TIMEOUT(to, NULL, NULL);
-               l_wait_event(rq_waitq, rq_state & (RQ_STOP | RQ_PRECLEANUP),
-                            &lwi);
-
-                /*
-                 * iterate & processing through the list. for each cld, process
-                 * its depending sptlrpc cld firstly (if any) and then itself.
-                 *
-                 * it's guaranteed any item in the list must have
-                 * reference > 0; and if cld_lostlock is set, at
-                 * least one reference is taken by the previous enqueue.
-                 */
-                cld_prev = NULL;
+               wait_event_idle_timeout(rq_waitq,
+                                       rq_state & (RQ_STOP | RQ_PRECLEANUP),
+                                       to/100);
+
+               /*
+                * iterate & processing through the list. for each cld, process
+                * its depending sptlrpc cld firstly (if any) and then itself.
+                *
+                * it's guaranteed any item in the list must have
+                * reference > 0; and if cld_lostlock is set, at
+                * least one reference is taken by the previous enqueue.
+                */
+               cld_prev = NULL;
 
                spin_lock(&config_list_lock);
                rq_state &= ~RQ_PRECLEANUP;
                list_for_each_entry(cld, &config_llog_list,
-                                       cld_list_chain) {
-                       if (!cld->cld_lostlock)
+                                   cld_list_chain) {
+                       if (!cld->cld_lostlock || cld->cld_stopping)
                                continue;
 
+                       /* hold reference to avoid being freed during
+                        * subsequent processing. */
+                       config_log_get(cld);
+                       cld->cld_lostlock = 0;
                        spin_unlock(&config_list_lock);
 
-                       LASSERT(atomic_read(&cld->cld_refcount) > 0);
-
-                       /* Whether we enqueued again or not in mgc_process_log,
-                        * we're done with the ref from the old enqueue */
-                       if (cld_prev)
-                               config_log_put(cld_prev);
+                       config_log_put(cld_prev);
                        cld_prev = cld;
 
-                        cld->cld_lostlock = 0;
-                       if (likely(!stopped))
+                       if (likely(!(rq_state & RQ_STOP))) {
                                do_requeue(cld);
-
-                       spin_lock(&config_list_lock);
+                               spin_lock(&config_list_lock);
+                       } else {
+                               spin_lock(&config_list_lock);
+                               break;
+                       }
                }
                spin_unlock(&config_list_lock);
-               if (cld_prev)
-                       config_log_put(cld_prev);
-
-               /* break after scanning the list so that we can drop
-                * refcount to losing lock clds */
-               if (unlikely(stopped)) {
-                       spin_lock(&config_list_lock);
-                       break;
-               }
+               config_log_put(cld_prev);
 
                /* Wait a bit to see if anyone else needs a requeue */
-               lwi = (struct l_wait_info) { 0 };
-               l_wait_event(rq_waitq, rq_state & (RQ_NOW | RQ_STOP),
-                            &lwi);
+               wait_event_idle(rq_waitq, rq_state & (RQ_NOW | RQ_STOP));
                spin_lock(&config_list_lock);
        }
+
        /* spinlock and while guarantee RQ_NOW and RQ_LATER are not set */
        rq_state &= ~RQ_RUNNING;
        spin_unlock(&config_list_lock);
@@ -679,6 +715,7 @@ static int mgc_requeue_thread(void *data)
    We are responsible for dropping the config log reference from here on out. */
 static void mgc_requeue_add(struct config_llog_data *cld)
 {
+       bool wakeup = false;
        ENTRY;
 
        CDEBUG(D_INFO, "log %s: requeue (r=%d sp=%d st=%x)\n",
@@ -686,27 +723,23 @@ static void mgc_requeue_add(struct config_llog_data *cld)
                cld->cld_stopping, rq_state);
        LASSERT(atomic_read(&cld->cld_refcount) > 0);
 
-       mutex_lock(&cld->cld_lock);
-       if (cld->cld_stopping || cld->cld_lostlock) {
-               mutex_unlock(&cld->cld_lock);
-               RETURN_EXIT;
-       }
-       /* this refcount will be released in mgc_requeue_thread. */
-       config_log_get(cld);
-       cld->cld_lostlock = 1;
-       mutex_unlock(&cld->cld_lock);
+       /* lets cancel an existent lock to mark cld as "lostlock" */
+       CDEBUG(D_INFO, "lockh %#llx\n", cld->cld_lockh.cookie);
+       if (!ldlm_lock_addref_try(&cld->cld_lockh, LCK_CR))
+               ldlm_lock_decref_and_cancel(&cld->cld_lockh, LCK_CR);
 
-       /* Hold lock for rq_state */
+       mutex_lock(&cld->cld_lock);
        spin_lock(&config_list_lock);
-       if (rq_state & RQ_STOP) {
-               spin_unlock(&config_list_lock);
-               cld->cld_lostlock = 0;
-               config_log_put(cld);
-       } else {
+       if (!(rq_state & RQ_STOP) && !cld->cld_stopping) {
+               cld->cld_lostlock = 1;
                rq_state |= RQ_NOW;
-               spin_unlock(&config_list_lock);
-               wake_up(&rq_waitq);
+               wakeup = true;
        }
+       spin_unlock(&config_list_lock);
+       mutex_unlock(&cld->cld_lock);
+       if (wakeup)
+               wake_up(&rq_waitq);
+
        EXIT;
 }
 
@@ -784,7 +817,7 @@ static int mgc_fs_setup(const struct lu_env *env, struct obd_device *obd,
        dto = local_file_find_or_create(env, cli->cl_mgc_los, root,
                                        MOUNT_CONFIGS_DIR,
                                        S_IFDIR | S_IRUGO | S_IWUSR | S_IXUGO);
-       lu_object_put_nocache(env, &root->do_lu);
+       dt_object_put_nocache(env, root);
        if (IS_ERR(dto))
                GOTO(out_los, rc = PTR_ERR(dto));
 
@@ -803,7 +836,7 @@ static int mgc_fs_setup(const struct lu_env *env, struct obd_device *obd,
        EXIT;
 out_llog:
        if (rc) {
-               lu_object_put(env, &cli->cl_mgc_configs_dir->do_lu);
+               dt_object_put(env, cli->cl_mgc_configs_dir);
                cli->cl_mgc_configs_dir = NULL;
        }
 out_los:
@@ -824,7 +857,7 @@ static int mgc_fs_cleanup(const struct lu_env *env, struct obd_device *obd)
 
        mgc_local_llog_fini(env, obd);
 
-       lu_object_put_nocache(env, &cli->cl_mgc_configs_dir->do_lu);
+       dt_object_put_nocache(env, cli->cl_mgc_configs_dir);
        cli->cl_mgc_configs_dir = NULL;
 
        local_oid_storage_fini(env, cli->cl_mgc_los);
@@ -912,7 +945,7 @@ static int mgc_cleanup(struct obd_device *obd)
 
         /* COMPAT_146 - old config logs may have added profiles we don't
            know about */
-        if (obd->obd_type->typ_refcnt <= 1)
+       if (atomic_read(&obd->obd_type->typ_refcnt) <= 1)
                 /* Only for the last mgc */
                 class_del_profiles();
 
@@ -943,11 +976,9 @@ static int mgc_setup(struct obd_device *obd, struct lustre_cfg *lcfg)
                GOTO(err_cleanup, rc);
        }
 
-#ifdef CONFIG_PROC_FS
-       obd->obd_vars = lprocfs_mgc_obd_vars;
-       lprocfs_obd_setup(obd);
-#endif
-       sptlrpc_lprocfs_cliobd_attach(obd);
+       rc = mgc_tunables_init(obd);
+       if (rc)
+               GOTO(err_sysfs, rc);
 
        if (atomic_inc_return(&mgc_count) == 1) {
                rq_state = 0;
@@ -960,7 +991,7 @@ static int mgc_setup(struct obd_device *obd, struct lustre_cfg *lcfg)
                        CERROR("%s: cannot start requeue thread: rc = %d; "
                               "no more log updates\n",
                               obd->obd_name, rc);
-                       GOTO(err_cleanup, rc);
+                       GOTO(err_sysfs, rc);
                }
                /* rc is the task_struct pointer of mgc_requeue_thread. */
                rc = 0;
@@ -969,6 +1000,8 @@ static int mgc_setup(struct obd_device *obd, struct lustre_cfg *lcfg)
 
        RETURN(rc);
 
+err_sysfs:
+       lprocfs_obd_cleanup(obd);
 err_cleanup:
        client_obd_cleanup(obd);
 err_decref:
@@ -1007,6 +1040,9 @@ static int mgc_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
 
                /* held at mgc_process_log(). */
                LASSERT(atomic_read(&cld->cld_refcount) > 0);
+
+               lock->l_ast_data = NULL;
+               cld->cld_lockh.cookie = 0;
                /* Are we done with this log? */
                if (cld->cld_stopping) {
                        CDEBUG(D_MGC, "log %s: stopping, won't requeue\n",
@@ -1041,49 +1077,13 @@ static int mgc_blocking_ast(struct ldlm_lock *lock, struct ldlm_lock_desc *desc,
 #define  MGC_ENQUEUE_LIMIT (INITIAL_CONNECT_TIMEOUT + (AT_OFF ? 0 : at_min) \
                                + PING_INTERVAL)
 #define  MGC_TARGET_REG_LIMIT 10
+#define  MGC_TARGET_REG_LIMIT_MAX RECONNECT_DELAY_MAX
 #define  MGC_SEND_PARAM_LIMIT 10
 
-/* Send parameter to MGS*/
-static int mgc_set_mgs_param(struct obd_export *exp,
-                             struct mgs_send_param *msp)
-{
-        struct ptlrpc_request *req;
-        struct mgs_send_param *req_msp, *rep_msp;
-        int rc;
-        ENTRY;
-
-        req = ptlrpc_request_alloc_pack(class_exp2cliimp(exp),
-                                        &RQF_MGS_SET_INFO, LUSTRE_MGS_VERSION,
-                                        MGS_SET_INFO);
-        if (!req)
-                RETURN(-ENOMEM);
-
-        req_msp = req_capsule_client_get(&req->rq_pill, &RMF_MGS_SEND_PARAM);
-        if (!req_msp) {
-                ptlrpc_req_finished(req);
-                RETURN(-ENOMEM);
-        }
-
-        memcpy(req_msp, msp, sizeof(*req_msp));
-        ptlrpc_request_set_replen(req);
-
-        /* Limit how long we will wait for the enqueue to complete */
-        req->rq_delay_limit = MGC_SEND_PARAM_LIMIT;
-        rc = ptlrpc_queue_wait(req);
-        if (!rc) {
-                rep_msp = req_capsule_server_get(&req->rq_pill, &RMF_MGS_SEND_PARAM);
-                memcpy(msp, rep_msp, sizeof(*rep_msp));
-        }
-
-        ptlrpc_req_finished(req);
-
-        RETURN(rc);
-}
-
 /* Take a config lock so we can get cancel notifications */
 static int mgc_enqueue(struct obd_export *exp, enum ldlm_type type,
                       union ldlm_policy_data *policy, enum ldlm_mode mode,
-                      __u64 *flags, void *bl_cb, void *cp_cb, void *gl_cb,
+                      __u64 *flags, ldlm_glimpse_callback glimpse_callback,
                       void *data, __u32 lvb_len, void *lvb_swabber,
                       struct lustre_handle *lockh)
 {
@@ -1093,12 +1093,16 @@ static int mgc_enqueue(struct obd_export *exp, enum ldlm_type type,
                .ei_mode        = mode,
                .ei_cb_bl       = mgc_blocking_ast,
                .ei_cb_cp       = ldlm_completion_ast,
+               .ei_cb_gl       = glimpse_callback,
        };
        struct ptlrpc_request *req;
        int short_limit = cld_is_sptlrpc(cld);
        int rc;
        ENTRY;
 
+       if (!exp)
+               RETURN(-EBADR);
+
        CDEBUG(D_MGC, "Enqueue for %s (res %#llx)\n", cld->cld_logname,
                cld->cld_resid.name[0]);
 
@@ -1171,11 +1175,18 @@ static int mgc_target_register(struct obd_export *exp,
                 RETURN(-ENOMEM);
         }
 
-        memcpy(req_mti, mti, sizeof(*req_mti));
-        ptlrpc_request_set_replen(req);
-        CDEBUG(D_MGC, "register %s\n", mti->mti_svname);
-        /* Limit how long we will wait for the enqueue to complete */
-        req->rq_delay_limit = MGC_TARGET_REG_LIMIT;
+       memcpy(req_mti, mti, sizeof(*req_mti));
+       ptlrpc_request_set_replen(req);
+       CDEBUG(D_MGC, "register %s\n", mti->mti_svname);
+       /* Limit how long we will wait for the enqueue to complete */
+       req->rq_delay_limit = MGC_TARGET_REG_LIMIT;
+
+       /* if the target needs to regenerate the config log in MGS, it's better
+        * to use some longer limit to let MGC have time to change connection to
+        * another MGS (or try again with the same MGS) for the target (server)
+        * will fail and exit if the request expired due to delay limit. */
+       if (mti->mti_flags & (LDD_F_UPDATE | LDD_F_NEED_INDEX))
+               req->rq_delay_limit = MGC_TARGET_REG_LIMIT_MAX;
 
         rc = ptlrpc_queue_wait(req);
         if (!rc) {
@@ -1198,24 +1209,28 @@ static int mgc_set_info_async(const struct lu_env *env, struct obd_export *exp,
         int rc = -EINVAL;
         ENTRY;
 
-        /* Turn off initial_recov after we try all backup servers once */
-        if (KEY_IS(KEY_INIT_RECOV_BACKUP)) {
-                struct obd_import *imp = class_exp2cliimp(exp);
-                int value;
-                if (vallen != sizeof(int))
-                        RETURN(-EINVAL);
-                value = *(int *)val;
-                CDEBUG(D_MGC, "InitRecov %s %d/d%d:i%d:r%d:or%d:%s\n",
-                       imp->imp_obd->obd_name, value,
-                       imp->imp_deactive, imp->imp_invalid,
-                       imp->imp_replayable, imp->imp_obd->obd_replayable,
-                       ptlrpc_import_state_name(imp->imp_state));
-                /* Resurrect if we previously died */
-                if ((imp->imp_state != LUSTRE_IMP_FULL &&
-                     imp->imp_state != LUSTRE_IMP_NEW) || value > 1)
-                        ptlrpc_reconnect_import(imp);
-                RETURN(0);
-        }
+       /* Turn off initial_recov after we try all backup servers once */
+       if (KEY_IS(KEY_INIT_RECOV_BACKUP)) {
+               struct obd_import *imp = class_exp2cliimp(exp);
+               int value;
+               if (vallen != sizeof(int))
+                       RETURN(-EINVAL);
+               value = *(int *)val;
+               CDEBUG(D_MGC, "InitRecov %s %d/d%d:i%d:r%d:or%d:%s\n",
+                      imp->imp_obd->obd_name, value,
+                      imp->imp_deactive, imp->imp_invalid,
+                      imp->imp_replayable, imp->imp_obd->obd_replayable,
+                      ptlrpc_import_state_name(imp->imp_state));
+               /* Resurrect the import immediately if
+                * 1. we previously got disconnected,
+                * 2. value > 1 (at the same node with MGS)
+                * */
+               if (imp->imp_state == LUSTRE_IMP_DISCON || value > 1)
+                       ptlrpc_reconnect_import(imp);
+
+               RETURN(0);
+       }
+
         /* FIXME move this to mgc_process_config */
         if (KEY_IS(KEY_REGISTER_TARGET)) {
                 struct mgs_target_info *mti;
@@ -1242,13 +1257,6 @@ static int mgc_set_info_async(const struct lu_env *env, struct obd_export *exp,
                rc = mgc_fs_cleanup(env, exp->exp_obd);
                RETURN(rc);
        }
-        if (KEY_IS(KEY_SET_INFO)) {
-                struct mgs_send_param *msp;
-
-                msp = (struct mgs_send_param *)val;
-                rc =  mgc_set_mgs_param(exp, msp);
-                RETURN(rc);
-        }
         if (KEY_IS(KEY_MGSSEC)) {
                 struct client_obd     *cli = &exp->exp_obd->u.cli;
                 struct sptlrpc_flavor  flvr;
@@ -1357,7 +1365,7 @@ static int mgc_import_event(struct obd_device *obd,
 }
 
 enum {
-       CONFIG_READ_NRPAGES_INIT = 1 << (20 - PAGE_CACHE_SHIFT),
+       CONFIG_READ_NRPAGES_INIT = 1 << (20 - PAGE_SHIFT),
         CONFIG_READ_NRPAGES      = 4
 };
 
@@ -1366,79 +1374,86 @@ static int mgc_apply_recover_logs(struct obd_device *mgc,
                                  __u64 max_version,
                                  void *data, int datalen, bool mne_swab)
 {
-        struct config_llog_instance *cfg = &cld->cld_cfg;
-        struct lustre_sb_info       *lsi = s2lsi(cfg->cfg_sb);
-        struct mgs_nidtbl_entry *entry;
-        struct lustre_cfg       *lcfg;
-        struct lustre_cfg_bufs   bufs;
-        u64   prev_version = 0;
-        char *inst;
-        char *buf;
-        int   bufsz;
-        int   pos;
-        int   rc  = 0;
-        int   off = 0;
-        ENTRY;
+       struct config_llog_instance *cfg = &cld->cld_cfg;
+       struct lustre_sb_info *lsi = s2lsi(cfg->cfg_sb);
+       struct mgs_nidtbl_entry *entry;
+       struct lustre_cfg *lcfg;
+       struct lustre_cfg_bufs bufs;
+       u64 prev_version = 0;
+       char *inst;
+       char *buf;
+       int bufsz;
+       int pos = 0;
+       int rc  = 0;
+       int off = 0;
+       unsigned long dynamic_nids;
 
-        LASSERT(cfg->cfg_instance != NULL);
-        LASSERT(cfg->cfg_sb == cfg->cfg_instance);
+       ENTRY;
+       LASSERT(cfg->cfg_instance != 0);
+       LASSERT(ll_get_cfg_instance(cfg->cfg_sb) == cfg->cfg_instance);
+
+       /* get dynamic nids setting */
+       dynamic_nids = mgc->obd_dynamic_nids;
 
-       OBD_ALLOC(inst, PAGE_CACHE_SIZE);
+       OBD_ALLOC(inst, PAGE_SIZE);
        if (inst == NULL)
                RETURN(-ENOMEM);
 
        if (!IS_SERVER(lsi)) {
-               pos = snprintf(inst, PAGE_CACHE_SIZE, "%p", cfg->cfg_instance);
-               if (pos >= PAGE_CACHE_SIZE) {
-                       OBD_FREE(inst, PAGE_CACHE_SIZE);
+               pos = snprintf(inst, PAGE_SIZE, "%016lx", cfg->cfg_instance);
+               if (pos >= PAGE_SIZE) {
+                       OBD_FREE(inst, PAGE_SIZE);
                        return -E2BIG;
                }
-        } else {
+#ifdef HAVE_SERVER_SUPPORT
+       } else {
                LASSERT(IS_MDT(lsi));
                rc = server_name2svname(lsi->lsi_svname, inst, NULL,
-                                       PAGE_CACHE_SIZE);
+                                       PAGE_SIZE);
                if (rc) {
-                       OBD_FREE(inst, PAGE_CACHE_SIZE);
+                       OBD_FREE(inst, PAGE_SIZE);
                        RETURN(-EINVAL);
                }
                pos = strlen(inst);
-        }
+#endif /* HAVE_SERVER_SUPPORT */
+       }
+
+       ++pos;
+       buf   = inst + pos;
+       bufsz = PAGE_SIZE - pos;
+
+       while (datalen > 0) {
+               int   entry_len = sizeof(*entry);
+               int   is_ost;
+               struct obd_device *obd;
+               struct obd_import *imp;
+               char *obdname;
+               char *cname;
+               char *params;
+               char *uuid;
+
+               rc = -EINVAL;
+               if (datalen < sizeof(*entry))
+                       break;
+
+               entry = (typeof(entry))(data + off);
+
+               /* sanity check */
+               if (entry->mne_nid_type != 0) /* only support type 0 for ipv4 */
+                       break;
+               if (entry->mne_nid_count == 0) /* at least one nid entry */
+                       break;
+               if (entry->mne_nid_size != sizeof(lnet_nid_t))
+                       break;
 
-        ++pos;
-        buf   = inst + pos;
-       bufsz = PAGE_CACHE_SIZE - pos;
-
-        while (datalen > 0) {
-                int   entry_len = sizeof(*entry);
-               int   is_ost, i;
-                struct obd_device *obd;
-                char *obdname;
-                char *cname;
-                char *params;
-                char *uuid;
-
-                rc = -EINVAL;
-                if (datalen < sizeof(*entry))
-                        break;
-
-                entry = (typeof(entry))(data + off);
-
-                /* sanity check */
-                if (entry->mne_nid_type != 0) /* only support type 0 for ipv4 */
-                        break;
-                if (entry->mne_nid_count == 0) /* at least one nid entry */
-                        break;
-                if (entry->mne_nid_size != sizeof(lnet_nid_t))
-                        break;
-
-                entry_len += entry->mne_nid_count * entry->mne_nid_size;
-                if (datalen < entry_len) /* must have entry_len at least */
-                        break;
+               entry_len += entry->mne_nid_count * entry->mne_nid_size;
+               if (datalen < entry_len) /* must have entry_len at least */
+                       break;
 
                /* Keep this swab for normal mixed endian handling. LU-1644 */
                if (mne_swab)
                        lustre_swab_mgs_nidtbl_entry(entry);
-               if (entry->mne_length > PAGE_CACHE_SIZE) {
+               if (entry->mne_length > PAGE_SIZE) {
                        CERROR("MNE too large (%u)\n", entry->mne_length);
                        break;
                }
@@ -1446,122 +1461,153 @@ static int mgc_apply_recover_logs(struct obd_device *mgc,
                if (entry->mne_length < entry_len)
                        break;
 
-                off     += entry->mne_length;
-                datalen -= entry->mne_length;
-                if (datalen < 0)
-                        break;
+               off     += entry->mne_length;
+               datalen -= entry->mne_length;
+               if (datalen < 0)
+                       break;
 
-                if (entry->mne_version > max_version) {
-                        CERROR("entry index(%lld) is over max_index(%lld)\n",
-                               entry->mne_version, max_version);
-                        break;
-                }
+               if (entry->mne_version > max_version) {
+                       CERROR("entry index(%lld) is over max_index(%lld)\n",
+                              entry->mne_version, max_version);
+                       break;
+               }
 
-                if (prev_version >= entry->mne_version) {
-                        CERROR("index unsorted, prev %lld, now %lld\n",
-                               prev_version, entry->mne_version);
-                        break;
-                }
-                prev_version = entry->mne_version;
+               if (prev_version >= entry->mne_version) {
+                       CERROR("index unsorted, prev %lld, now %lld\n",
+                              prev_version, entry->mne_version);
+                       break;
+               }
+               prev_version = entry->mne_version;
 
-                /*
-                 * Write a string with format "nid::instance" to
-                 * lustre/<osc|mdc>/<target>-<osc|mdc>-<instance>/import.
-                 */
+               /*
+                * Write a string with format "nid::instance" to
+                * lustre/<osc|mdc>/<target>-<osc|mdc>-<instance>/import.
+                */
 
-                is_ost = entry->mne_type == LDD_F_SV_TYPE_OST;
-                memset(buf, 0, bufsz);
-                obdname = buf;
-                pos = 0;
-
-                /* lustre-OST0001-osc-<instance #> */
-                strcpy(obdname, cld->cld_logname);
-                cname = strrchr(obdname, '-');
-                if (cname == NULL) {
-                        CERROR("mgc %s: invalid logname %s\n",
-                               mgc->obd_name, obdname);
-                        break;
-                }
+               is_ost = entry->mne_type == LDD_F_SV_TYPE_OST;
+               memset(buf, 0, bufsz);
+               obdname = buf;
+               pos = 0;
+
+               /* lustre-OST0001-osc-<instance #> */
+               strcpy(obdname, cld->cld_logname);
+               cname = strrchr(obdname, '-');
+               if (cname == NULL) {
+                       CERROR("mgc %s: invalid logname %s\n",
+                              mgc->obd_name, obdname);
+                       break;
+               }
 
-                pos = cname - obdname;
-                obdname[pos] = 0;
-                pos += sprintf(obdname + pos, "-%s%04x",
-                                  is_ost ? "OST" : "MDT", entry->mne_index);
+               pos = cname - obdname;
+               obdname[pos] = 0;
+               pos += sprintf(obdname + pos, "-%s%04x",
+                              is_ost ? "OST" : "MDT", entry->mne_index);
 
-                cname = is_ost ? "osc" : "mdc",
-                pos += sprintf(obdname + pos, "-%s-%s", cname, inst);
-                lustre_cfg_bufs_reset(&bufs, obdname);
+               cname = is_ost ? "osc" : "mdc",
+                       pos += sprintf(obdname + pos, "-%s-%s", cname, inst);
+               lustre_cfg_bufs_reset(&bufs, obdname);
 
-                /* find the obd by obdname */
-                obd = class_name2obd(obdname);
-                if (obd == NULL) {
-                        CDEBUG(D_INFO, "mgc %s: cannot find obdname %s\n",
-                               mgc->obd_name, obdname);
+               /* find the obd by obdname */
+               obd = class_name2obd(obdname);
+               if (obd == NULL) {
+                       CDEBUG(D_INFO, "mgc %s: cannot find obdname %s\n",
+                              mgc->obd_name, obdname);
                        rc = 0;
-                        /* this is a safe race, when the ost is starting up...*/
-                        continue;
-                }
-
-                /* osc.import = "connection=<Conn UUID>::<target instance>" */
-                ++pos;
-                params = buf + pos;
-                pos += sprintf(params, "%s.import=%s", cname, "connection=");
-                uuid = buf + pos;
+                       /* this is a safe race, when the ost is starting up...*/
+                       continue;
+               }
 
-               down_read(&obd->u.cli.cl_sem);
-               if (obd->u.cli.cl_import == NULL) {
+               /* osc.import = "connection=<Conn UUID>::<target instance>" */
+               ++pos;
+               params = buf + pos;
+               pos += sprintf(params, "%s.import=%s", cname, "connection=");
+               uuid = buf + pos;
+
+               with_imp_locked(obd, imp, rc) {
+                       /* iterate all nids to find one */
+                       /* find uuid by nid */
+                       /* create import entries if they don't exist */
+                       rc = client_import_add_nids_to_conn(
+                               imp, entry->u.nids, entry->mne_nid_count,
+                               (struct obd_uuid *)uuid);
+
+                       if (rc == -ENOENT && dynamic_nids) {
+                               /* create a new connection for this import */
+                               char *primary_nid =
+                                       libcfs_nid2str(entry->u.nids[0]);
+                               int prim_nid_len = strlen(primary_nid) + 1;
+                               struct obd_uuid server_uuid;
+
+                               if (prim_nid_len > UUID_MAX)
+                                       goto fail;
+                               strncpy(server_uuid.uuid, primary_nid,
+                                       prim_nid_len);
+
+                               CDEBUG(D_INFO, "Adding a connection for %s\n",
+                                      primary_nid);
+
+                               rc = client_import_dyn_add_conn(
+                                       imp, &server_uuid, entry->u.nids[0], 1);
+                               if (rc < 0) {
+                                       CERROR("%s: Failed to add new connection with NID '%s' to import: rc = %d\n",
+                                              obd->obd_name, primary_nid, rc);
+                                       goto fail;
+                               }
+                               rc = client_import_add_nids_to_conn(
+                                       imp, entry->u.nids,
+                                       entry->mne_nid_count,
+                                       (struct obd_uuid *)uuid);
+                               if (rc < 0) {
+                                       CERROR("%s: failed to lookup UUID: rc = %d\n",
+                                              obd->obd_name, rc);
+                                       goto fail;
+                               }
+                       }
+fail:;
+               }
+               if (rc == -ENODEV) {
                        /* client does not connect to the OST yet */
-                       up_read(&obd->u.cli.cl_sem);
                        rc = 0;
                        continue;
                }
 
-               /* iterate all nids to find one */
-               /* find uuid by nid */
-               rc = -ENOENT;
-               for (i = 0; i < entry->mne_nid_count; i++) {
-                       rc = client_import_find_conn(obd->u.cli.cl_import,
-                                                    entry->u.nids[i],
-                                                    (struct obd_uuid *)uuid);
-                       if (rc == 0)
-                               break;
+               if (rc < 0 && rc != -ENOSPC) {
+                       CERROR("mgc: cannot find UUID by nid '%s': rc = %d\n",
+                              libcfs_nid2str(entry->u.nids[0]), rc);
+                       break;
                }
 
-               up_read(&obd->u.cli.cl_sem);
-                if (rc < 0) {
-                        CERROR("mgc: cannot find uuid by nid %s\n",
-                               libcfs_nid2str(entry->u.nids[0]));
-                        break;
-                }
+               CDEBUG(D_INFO, "Found UUID '%s' by NID '%s'\n",
+                      uuid, libcfs_nid2str(entry->u.nids[0]));
 
-                CDEBUG(D_INFO, "Find uuid %s by nid %s\n",
-                       uuid, libcfs_nid2str(entry->u.nids[0]));
+               pos += strlen(uuid);
+               pos += sprintf(buf + pos, "::%u", entry->mne_instance);
+               LASSERT(pos < bufsz);
 
-                pos += strlen(uuid);
-                pos += sprintf(buf + pos, "::%u", entry->mne_instance);
-                LASSERT(pos < bufsz);
+               lustre_cfg_bufs_set_string(&bufs, 1, params);
 
-                lustre_cfg_bufs_set_string(&bufs, 1, params);
-
-               lcfg = lustre_cfg_new(LCFG_PARAM, &bufs);
-               if (lcfg == NULL) {
+               OBD_ALLOC(lcfg, lustre_cfg_len(bufs.lcfg_bufcount,
+                                              bufs.lcfg_buflen));
+               if (!lcfg) {
                        rc = -ENOMEM;
                        break;
                }
+               lustre_cfg_init(lcfg, LCFG_PARAM, &bufs);
 
                CDEBUG(D_INFO, "ir apply logs %lld/%lld for %s -> %s\n",
-                       prev_version, max_version, obdname, params);
+                      prev_version, max_version, obdname, params);
 
-                rc = class_process_config(lcfg);
-                lustre_cfg_free(lcfg);
-                if (rc)
-                        CDEBUG(D_INFO, "process config for %s error %d\n",
-                               obdname, rc);
+               rc = class_process_config(lcfg);
+               OBD_FREE(lcfg, lustre_cfg_len(lcfg->lcfg_bufcount,
+                                             lcfg->lcfg_buflens));
+               if (rc)
+                       CDEBUG(D_INFO, "process config for %s error %d\n",
+                              obdname, rc);
 
-                /* continue, even one with error */
-        }
+               /* continue, even one with error */
+       }
 
-       OBD_FREE(inst, PAGE_CACHE_SIZE);
+       OBD_FREE(inst, PAGE_SIZE);
         RETURN(rc);
 }
 
@@ -1583,6 +1629,7 @@ static int mgc_process_recover_nodemap_log(struct obd_device *obd,
        struct ptlrpc_bulk_desc *desc;
        struct page **pages = NULL;
        __u64 config_read_offset = 0;
+       __u8 nodemap_cur_pass = 0;
        int nrpages = 0;
        bool eof = true;
        bool mne_swab = false;
@@ -1594,29 +1641,28 @@ static int mgc_process_recover_nodemap_log(struct obd_device *obd,
        mgc_conn = class_exp2cliimp(cld->cld_mgcexp)->imp_connection;
 
        /* don't need to get local config */
-       if (cld_is_nodemap(cld) &&
-           (LNET_NETTYP(LNET_NIDNET(mgc_conn->c_peer.nid)) == LOLND))
+       if (cld_is_nodemap(cld) && LNetIsPeerLocal(mgc_conn->c_peer.nid))
                GOTO(out, rc = 0);
 
-        /* allocate buffer for bulk transfer.
-         * if this is the first time for this mgs to read logs,
-         * CONFIG_READ_NRPAGES_INIT will be used since it will read all logs
-         * once; otherwise, it only reads increment of logs, this should be
-         * small and CONFIG_READ_NRPAGES will be used.
-         */
-        nrpages = CONFIG_READ_NRPAGES;
+       /* allocate buffer for bulk transfer.
+        * if this is the first time for this mgs to read logs,
+        * CONFIG_READ_NRPAGES_INIT will be used since it will read all logs
+        * once; otherwise, it only reads increment of logs, this should be
+        * small and CONFIG_READ_NRPAGES will be used.
+        */
+       nrpages = CONFIG_READ_NRPAGES;
        if (cfg->cfg_last_idx == 0 || cld_is_nodemap(cld))
-                nrpages = CONFIG_READ_NRPAGES_INIT;
+               nrpages = CONFIG_READ_NRPAGES_INIT;
 
-        OBD_ALLOC(pages, sizeof(*pages) * nrpages);
-        if (pages == NULL)
-                GOTO(out, rc = -ENOMEM);
+       OBD_ALLOC_PTR_ARRAY(pages, nrpages);
+       if (pages == NULL)
+               GOTO(out, rc = -ENOMEM);
 
-        for (i = 0; i < nrpages; i++) {
+       for (i = 0; i < nrpages; i++) {
                pages[i] = alloc_page(GFP_KERNEL);
-                if (pages[i] == NULL)
-                        GOTO(out, rc = -ENOMEM);
-        }
+               if (pages[i] == NULL)
+                       GOTO(out, rc = -ENOMEM);
+       }
 
 again:
 #ifdef HAVE_SERVER_SUPPORT
@@ -1652,12 +1698,13 @@ again:
        else
                body->mcb_offset = cfg->cfg_last_idx + 1;
        body->mcb_type   = cld->cld_type;
-       body->mcb_bits   = PAGE_CACHE_SHIFT;
+       body->mcb_bits   = PAGE_SHIFT;
        body->mcb_units  = nrpages;
+       body->mcb_nm_cur_pass = nodemap_cur_pass;
 
        /* allocate bulk transfer descriptor */
        desc = ptlrpc_prep_bulk_imp(req, nrpages, 1,
-                                   PTLRPC_BULK_PUT_SINK | PTLRPC_BULK_BUF_KIOV,
+                                   PTLRPC_BULK_PUT_SINK,
                                    MGS_BULK_PORTAL,
                                    &ptlrpc_bulk_kiov_pin_ops);
        if (desc == NULL)
@@ -1665,7 +1712,7 @@ again:
 
        for (i = 0; i < nrpages; i++)
                desc->bd_frag_ops->add_kiov_frag(desc, pages[i], 0,
-                                                PAGE_CACHE_SIZE);
+                                                PAGE_SIZE);
 
        ptlrpc_request_set_replen(req);
        rc = ptlrpc_queue_wait(req);
@@ -1679,6 +1726,7 @@ again:
        if (cld_is_nodemap(cld)) {
                config_read_offset = res->mcr_offset;
                eof = config_read_offset == II_END_OFF;
+               nodemap_cur_pass = res->mcr_nm_cur_pass;
        } else {
                if (res->mcr_size < res->mcr_offset)
                        GOTO(out, rc = -EINVAL);
@@ -1697,22 +1745,15 @@ again:
        if (ealen < 0)
                GOTO(out, rc = ealen);
 
-       if (ealen > nrpages << PAGE_CACHE_SHIFT)
+       if (ealen > nrpages << PAGE_SHIFT)
                GOTO(out, rc = -EINVAL);
 
        if (ealen == 0) { /* no logs transferred */
 #ifdef HAVE_SERVER_SUPPORT
                /* config changed since first read RPC */
                if (cld_is_nodemap(cld) && config_read_offset == 0) {
-                       recent_nodemap = NULL;
-                       nodemap_config_dealloc(new_config);
-                       new_config = NULL;
-
                        CDEBUG(D_INFO, "nodemap config changed in transit, retrying\n");
-
-                       /* setting eof to false, we request config again */
-                       eof = false;
-                       GOTO(out, rc = 0);
+                       GOTO(out, rc = -EAGAIN);
                }
 #endif
                if (!eof)
@@ -1720,13 +1761,7 @@ again:
                GOTO(out, rc);
        }
 
-       mne_swab = !!ptlrpc_rep_need_swab(req);
-#if LUSTRE_VERSION_CODE < OBD_OCD_VERSION(3, 0, 53, 0)
-       /* This import flag means the server did an extra swab of IR MNE
-        * records (fixed in LU-1252), reverse it here if needed. LU-1644 */
-       if (unlikely(req->rq_import->imp_need_mne_swab))
-               mne_swab = !mne_swab;
-#endif
+       mne_swab = ptlrpc_rep_need_swab(req);
 
        /* When a nodemap config is received, we build a new nodemap config,
         * with new nodemap structs. We keep track of the most recently added
@@ -1749,7 +1784,7 @@ again:
                        rc2 = mgc_apply_recover_logs(obd, cld, res->mcr_offset,
                                                     ptr,
                                                     min_t(int, ealen,
-                                                          PAGE_CACHE_SIZE),
+                                                          PAGE_SIZE),
                                                     mne_swab);
                kunmap(pages[i]);
                if (rc2 < 0) {
@@ -1758,10 +1793,10 @@ again:
                              cld_is_nodemap(cld) ? "nodemap" : "recovery",
                              cld->cld_logname,
                              rc2);
-                       break;
+                       GOTO(out, rc = rc2);
                }
 
-               ealen -= PAGE_CACHE_SIZE;
+               ealen -= PAGE_SIZE;
        }
 
 out:
@@ -1789,11 +1824,26 @@ out:
                                break;
                        __free_page(pages[i]);
                }
-               OBD_FREE(pages, sizeof(*pages) * nrpages);
+               OBD_FREE_PTR_ARRAY(pages, nrpages);
        }
        return rc;
 }
 
+static int mgc_barrier_glimpse_ast(struct ldlm_lock *lock, void *data)
+{
+       struct config_llog_data *cld = lock->l_ast_data;
+       int rc;
+       ENTRY;
+
+       if (cld->cld_stopping)
+               RETURN(-ENODEV);
+
+       rc = barrier_handler(s2lsi(cld->cld_cfg.cfg_sb)->lsi_dt_dev,
+                            (struct ptlrpc_request *)data);
+
+       RETURN(rc);
+}
+
 /* Copy a remote log locally */
 static int mgc_llog_local_copy(const struct lu_env *env,
                               struct obd_device *obd,
@@ -1845,7 +1895,6 @@ static int mgc_process_cfg_log(struct obd_device *mgc,
        struct client_obd       *cli = &mgc->u.cli;
        struct lustre_sb_info   *lsi = NULL;
        int                      rc = 0;
-       bool                     sptlrpc_started = false;
        struct lu_env           *env;
 
        ENTRY;
@@ -1853,13 +1902,6 @@ static int mgc_process_cfg_log(struct obd_device *mgc,
        LASSERT(cld);
        LASSERT(mutex_is_locked(&cld->cld_lock));
 
-       /*
-        * local copy of sptlrpc log is controlled elsewhere, don't try to
-        * read it up here.
-        */
-       if (cld_is_sptlrpc(cld) && local_only)
-               RETURN(0);
-
        if (cld->cld_cfg.cfg_sb)
                lsi = s2lsi(cld->cld_cfg.cfg_sb);
 
@@ -1882,21 +1924,32 @@ 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. */
+                       CDEBUG(D_INFO, "%s: copy local log %s\n",
+                              mgc->obd_name, cld->cld_logname);
+
                        rc = mgc_llog_local_copy(env, mgc, ctxt, lctxt,
                                                 cld->cld_logname);
+                       if (!rc)
+                               lsi->lsi_flags &= ~LDD_F_NO_LOCAL_LOGS;
+               }
                if (local_only || rc) {
+                       if (unlikely(lsi->lsi_flags & LDD_F_NO_LOCAL_LOGS)
+                           || rc) {
+                               CWARN("%s: local log %s are not valid and/or remote logs are not accessbile rc = %d\n",
+                                     mgc->obd_name, cld->cld_logname, rc);
+                               GOTO(out_pop, rc = -EIO);
+                       }
+
                        if (strcmp(cld->cld_logname, PARAMS_FILENAME) != 0 &&
                            llog_is_empty(env, lctxt, cld->cld_logname)) {
-                               LCONSOLE_ERROR_MSG(0x13a, "Failed to get MGS "
-                                                  "log %s and no local copy."
-                                                  "\n", cld->cld_logname);
+                               LCONSOLE_ERROR_MSG(0x13a, "Failed to get MGS log %s and no local copy.\n",
+                                                  cld->cld_logname);
                                GOTO(out_pop, rc = -ENOENT);
                        }
-                       CDEBUG(D_MGC, "Failed to get MGS log %s, using local "
-                              "copy for now, will try to update later.\n",
-                              cld->cld_logname);
+                       CDEBUG(D_MGC, "%s: Failed to get MGS log %s, using local copy for now, will try to update later.\n",
+                              mgc->obd_name, cld->cld_logname);
                        rc = 0;
                }
                /* Now, whether we copied or not, start using the local llog.
@@ -1910,36 +1963,39 @@ static int mgc_process_cfg_log(struct obd_device *mgc,
                        GOTO(out_pop, rc = -EIO);
        }
 
-       if (cld_is_sptlrpc(cld)) {
-               sptlrpc_conf_log_update_begin(cld->cld_logname);
-               sptlrpc_started = true;
-       }
+       rc = -EAGAIN;
+       if (lsi && IS_SERVER(lsi) && !IS_MGS(lsi) &&
+           lsi->lsi_dt_dev->dd_rdonly) {
+               struct llog_ctxt *rctxt;
 
-       /* 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);
-       EXIT;
+               /* 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);
 
-out_pop:
-       __llog_ctxt_put(env, ctxt);
-       if (lctxt)
-               __llog_ctxt_put(env, lctxt);
+               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
-        * of llog_process_lock so no device is attaching/detaching
-        * in parallel.
+        * update settings on existing OBDs.
         * the logname must be <fsname>-sptlrpc
         */
-       if (sptlrpc_started) {
-               LASSERT(cld_is_sptlrpc(cld));
-               sptlrpc_conf_log_update_end(cld->cld_logname);
+       if (rc == 0 && cld_is_sptlrpc(cld))
                class_notify_sptlrpc_conf(cld->cld_logname,
                                          strlen(cld->cld_logname) -
                                          strlen("-sptlrpc"));
-       }
+       EXIT;
+
+out_pop:
+       __llog_ctxt_put(env, ctxt);
+       if (lctxt)
+               __llog_ctxt_put(env, lctxt);
 
        lu_env_fini(env);
 out_free:
@@ -2006,31 +2062,34 @@ restart:
        mutex_lock(&cld->cld_lock);
        if (cld->cld_stopping) {
                mutex_unlock(&cld->cld_lock);
-                RETURN(0);
-        }
+               RETURN(0);
+       }
 
-        OBD_FAIL_TIMEOUT(OBD_FAIL_MGC_PAUSE_PROCESS_LOG, 20);
+       OBD_FAIL_TIMEOUT(OBD_FAIL_MGC_PAUSE_PROCESS_LOG, 20);
 
-       CDEBUG(D_MGC, "Process log %s:%p from %d\n", cld->cld_logname,
+       CDEBUG(D_MGC, "Process log %s-%016lx from %d\n", cld->cld_logname,
               cld->cld_cfg.cfg_instance, cld->cld_cfg.cfg_last_idx + 1);
 
        /* Get the cfg lock on the llog */
        rcl = mgc_enqueue(mgc->u.cli.cl_mgc_mgsexp, LDLM_PLAIN, NULL,
-                         LCK_CR, &flags, NULL, NULL, NULL,
+                         LCK_CR, &flags,
+                         cld_is_barrier(cld) ? mgc_barrier_glimpse_ast : NULL,
                          cld, 0, NULL, &lockh);
        if (rcl == 0) {
                /* Get the cld, it will be released in mgc_blocking_ast. */
                config_log_get(cld);
                rc = ldlm_lock_set_data(&lockh, (void *)cld);
+               LASSERT(!lustre_handle_is_used(&cld->cld_lockh));
                LASSERT(rc == 0);
+               cld->cld_lockh = lockh;
        } else {
                CDEBUG(D_MGC, "Can't get cfg lock: %d\n", rcl);
+               cld->cld_lockh.cookie = 0;
 
                if (rcl == -ESHUTDOWN &&
                    atomic_read(&mgc->u.cli.cl_mgc_refcount) > 0 && !retry) {
                        struct obd_import *imp;
-                       struct l_wait_info lwi;
-                       int secs = cfs_time_seconds(obd_timeout);
+                       long timeout = cfs_time_seconds(obd_timeout);
 
                        mutex_unlock(&cld->cld_lock);
                        imp = class_exp2cliimp(mgc->u.cli.cl_mgc_mgsexp);
@@ -2043,56 +2102,63 @@ restart:
                         * FULL or closed */
                        ptlrpc_pinger_force(imp);
 
-                       lwi = LWI_TIMEOUT(secs, NULL, NULL);
-                       l_wait_event(imp->imp_recovery_waitq,
-                                    !mgc_import_in_recovery(imp), &lwi);
+                       wait_event_idle_timeout(imp->imp_recovery_waitq,
+                                               !mgc_import_in_recovery(imp),
+                                               timeout);
 
                        if (imp->imp_state == LUSTRE_IMP_FULL) {
                                retry = true;
                                goto restart;
                        } else {
                                mutex_lock(&cld->cld_lock);
+                               /* unlock/lock mutex, so check stopping again */
+                               if (cld->cld_stopping) {
+                                       mutex_unlock(&cld->cld_lock);
+                                       RETURN(0);
+                               }
+                               spin_lock(&config_list_lock);
                                cld->cld_lostlock = 1;
+                               spin_unlock(&config_list_lock);
                        }
                } else {
                        /* mark cld_lostlock so that it will requeue
                         * after MGC becomes available. */
+                       spin_lock(&config_list_lock);
                        cld->cld_lostlock = 1;
+                       spin_unlock(&config_list_lock);
                }
-               /* Get extra reference, it will be put in requeue thread */
-               config_log_get(cld);
        }
 
-
        if (cld_is_recover(cld) || cld_is_nodemap(cld)) {
                if (!rcl)
                        rc = mgc_process_recover_nodemap_log(mgc, cld);
                else if (cld_is_nodemap(cld))
                        rc = rcl;
 
-               if (cld_is_recover(cld) && rc) {
-                       if (!rcl) {
-                               CERROR("%s: recover log %s failed, not fatal: rc = %d\n",
-                                      mgc->obd_name, cld->cld_logname, rc);
-                               cld->cld_lostlock = 1;
-                       }
-                       rc = 0; /* this is not a fatal error for recover log */
-               }
-       } else {
+       } else if (!cld_is_barrier(cld)) {
                rc = mgc_process_cfg_log(mgc, cld, rcl != 0);
        }
 
        CDEBUG(D_MGC, "%s: configuration from log '%s' %sed (%d).\n",
               mgc->obd_name, cld->cld_logname, rc ? "fail" : "succeed", rc);
 
-       mutex_unlock(&cld->cld_lock);
-
        /* Now drop the lock so MGS can revoke it */
        if (!rcl) {
                rcl = mgc_cancel(mgc->u.cli.cl_mgc_mgsexp, LCK_CR, &lockh);
                if (rcl)
                        CERROR("Can't drop cfg lock: %d\n", rcl);
        }
+       mutex_unlock(&cld->cld_lock);
+
+       /* requeue nodemap lock immediately if transfer was interrupted */
+       if ((cld_is_nodemap(cld) && rc == -EAGAIN) ||
+           (cld_is_recover(cld) && rc)) {
+               if (cld_is_recover(cld))
+                       CWARN("%s: IR log %s failed, not fatal: rc = %d\n",
+                             mgc->obd_name, cld->cld_logname, rc);
+               mgc_requeue_add(cld);
+               rc = 0;
+       }
 
        RETURN(rc);
 }
@@ -2146,33 +2212,30 @@ static int mgc_process_config(struct obd_device *obd, size_t len, void *buf)
                        cfg->cfg_last_idx);
 
                 /* We're only called through here on the initial mount */
-                rc = config_log_add(obd, logname, cfg, sb);
-                if (rc)
-                        break;
-                cld = config_log_find(logname, cfg);
-                if (cld == NULL) {
-                        rc = -ENOENT;
-                        break;
-                }
+               cld = config_log_add(obd, logname, cfg, sb);
+               if (IS_ERR(cld)) {
+                       rc = PTR_ERR(cld);
+                       break;
+               }
 
-                /* COMPAT_146 */
-                /* FIXME only set this for old logs!  Right now this forces
-                   us to always skip the "inside markers" check */
-                cld->cld_cfg.cfg_flags |= CFG_F_COMPAT146;
-
-                rc = mgc_process_log(obd, cld);
-                if (rc == 0 && cld->cld_recover != NULL) {
-                        if (OCD_HAS_FLAG(&obd->u.cli.cl_import->
-                                         imp_connect_data, IMP_RECOV)) {
-                                rc = mgc_process_log(obd, cld->cld_recover);
-                        } else {
-                                struct config_llog_data *cir = cld->cld_recover;
-                                cld->cld_recover = NULL;
-                                config_log_put(cir);
-                        }
-                        if (rc)
-                                CERROR("Cannot process recover llog %d\n", rc);
-                }
+               rc = mgc_process_log(obd, cld);
+               if (rc == 0 && cld->cld_recover != NULL) {
+                       if (OCD_HAS_FLAG(&obd->u.cli.cl_import->
+                                        imp_connect_data, IMP_RECOV)) {
+                               rc = mgc_process_log(obd, cld->cld_recover);
+                       } else {
+                               struct config_llog_data *cir;
+
+                               mutex_lock(&cld->cld_lock);
+                               cir = cld->cld_recover;
+                               cld->cld_recover = NULL;
+                               mutex_unlock(&cld->cld_lock);
+                               config_log_put(cir);
+                       }
+
+                       if (rc)
+                               CERROR("Cannot process recover llog %d\n", rc);
+               }
 
                if (rc == 0 && cld->cld_params != NULL) {
                        rc = mgc_process_log(obd, cld->cld_params);
@@ -2186,7 +2249,6 @@ static int mgc_process_config(struct obd_device *obd, size_t len, void *buf)
                                CERROR("%s: can't process params llog: rc = %d\n",
                                       obd->obd_name, rc);
                }
-                config_log_put(cld);
 
                 break;
         }
@@ -2209,7 +2271,7 @@ out:
         RETURN(rc);
 }
 
-static struct obd_ops mgc_obd_ops = {
+static const struct obd_ops mgc_obd_ops = {
         .o_owner        = THIS_MODULE,
         .o_setup        = mgc_setup,
         .o_precleanup   = mgc_precleanup,
@@ -2226,7 +2288,7 @@ static struct obd_ops mgc_obd_ops = {
 
 static int __init mgc_init(void)
 {
-       return class_register_type(&mgc_obd_ops, NULL, true, NULL,
+       return class_register_type(&mgc_obd_ops, NULL, false,
                                   LUSTRE_MGC_NAME, NULL);
 }