X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=blobdiff_plain;f=lustre%2Fptlrpc%2Fnodemap_storage.c;h=72ce072148ab1431d7f06e111216a58694c4b72c;hp=dc956a8e964ff3789021a03a16397c8b357e8754;hb=6601661f96325b4971d0d1cb0be0fa01cc2ddc97;hpb=928714dddabb2dbc4fc93101f23eaa671099dbea

diff --git a/lustre/ptlrpc/nodemap_storage.c b/lustre/ptlrpc/nodemap_storage.c
index dc956a8..72ce072 100644
--- a/lustre/ptlrpc/nodemap_storage.c
+++ b/lustre/ptlrpc/nodemap_storage.c
@@ -22,7 +22,7 @@
 /*
  * Copyright (C) 2015, Trustees of Indiana University
  *
- * Copyright (c) 2014, Intel Corporation.
+ * Copyright (c) 2017, Intel Corporation.
  *
  * Author: Joshua Walgenbach <jjw@iu.edu>
  * Author: Kit Westneat <cwestnea@iu.edu>
@@ -50,8 +50,8 @@
 #include <linux/mutex.h>
 #include <linux/string.h>
 #include <linux/types.h>
-#include <lnet/types.h>
-#include <lustre/lustre_idl.h>
+#include <uapi/linux/lnet/lnet-types.h>
+#include <uapi/linux/lustre/lustre_idl.h>
 #include <dt_object.h>
 #include <lu_object.h>
 #include <lustre_net.h>
@@ -60,14 +60,21 @@
 #include <obd_support.h>
 #include "nodemap_internal.h"
 
-/* list of registered nodemap index files */
+/* list of registered nodemap index files, except MGS */
 static LIST_HEAD(ncf_list_head);
 static DEFINE_MUTEX(ncf_list_lock);
 
+/* MGS index is different than others, others are listeners to MGS idx */
+static struct nm_config_file *nodemap_mgs_ncf;
+
 /* lu_nodemap flags */
 enum nm_flag_shifts {
 	NM_FL_ALLOW_ROOT_ACCESS = 0x1,
 	NM_FL_TRUST_CLIENT_IDS = 0x2,
+	NM_FL_DENY_UNKNOWN = 0x4,
+	NM_FL_MAP_UID_ONLY = 0x8,
+	NM_FL_MAP_GID_ONLY = 0x10,
+	NM_FL_ENABLE_AUDIT = 0x20,
 };
 
 static void nodemap_cluster_key_init(struct nodemap_key *nk, unsigned int nm_id)
@@ -82,12 +89,22 @@ static void nodemap_cluster_rec_init(union nodemap_rec *nr,
 {
 	CLASSERT(sizeof(nr->ncr.ncr_name) == sizeof(nodemap->nm_name));
 
-	strncpy(nr->ncr.ncr_name, nodemap->nm_name, sizeof(nodemap->nm_name));
+	strncpy(nr->ncr.ncr_name, nodemap->nm_name, sizeof(nr->ncr.ncr_name));
 	nr->ncr.ncr_squash_uid = cpu_to_le32(nodemap->nm_squash_uid);
 	nr->ncr.ncr_squash_gid = cpu_to_le32(nodemap->nm_squash_gid);
 	nr->ncr.ncr_flags = cpu_to_le32(
-		(nodemap->nmf_trust_client_ids ? NM_FL_TRUST_CLIENT_IDS : 0) |
-		(nodemap->nmf_allow_root_access ? NM_FL_ALLOW_ROOT_ACCESS : 0));
+		(nodemap->nmf_trust_client_ids ?
+			NM_FL_TRUST_CLIENT_IDS : 0) |
+		(nodemap->nmf_allow_root_access ?
+			NM_FL_ALLOW_ROOT_ACCESS : 0) |
+		(nodemap->nmf_deny_unknown ?
+			NM_FL_DENY_UNKNOWN : 0) |
+		(nodemap->nmf_map_uid_only ?
+			NM_FL_MAP_UID_ONLY : 0) |
+		(nodemap->nmf_map_gid_only ?
+			NM_FL_MAP_GID_ONLY : 0) |
+		(nodemap->nmf_enable_audit ?
+			NM_FL_ENABLE_AUDIT : 0));
 }
 
 static void nodemap_idmap_key_init(struct nodemap_key *nk, unsigned int nm_id,
@@ -145,14 +162,92 @@ static void nodemap_inc_version(const struct lu_env *env,
 	dt_version_set(env, nodemap_idx, ver + 1, th);
 }
 
-static int nodemap_idx_insert(struct lu_env *env,
+enum ncfc_find_create {
+	NCFC_CREATE_NEW = 1,
+};
+
+static struct dt_object *nodemap_cache_find_create(const struct lu_env *env,
+						   struct dt_device *dev,
+						   struct local_oid_storage *los,
+						   enum ncfc_find_create create_new)
+{
+	struct lu_fid tfid;
+	struct dt_object *root_obj;
+	struct dt_object *nm_obj;
+	int rc = 0;
+
+	rc = dt_root_get(env, dev, &tfid);
+	if (rc < 0)
+		GOTO(out, nm_obj = ERR_PTR(rc));
+
+	root_obj = dt_locate(env, dev, &tfid);
+	if (unlikely(IS_ERR(root_obj)))
+		GOTO(out, nm_obj = root_obj);
+
+	rc = dt_lookup_dir(env, root_obj, LUSTRE_NODEMAP_NAME, &tfid);
+	if (rc == -ENOENT) {
+		if (dev->dd_rdonly)
+			GOTO(out_root, nm_obj = ERR_PTR(-EROFS));
+	} else if (rc) {
+		GOTO(out_root, nm_obj = ERR_PTR(rc));
+	} else if (dev->dd_rdonly && create_new == NCFC_CREATE_NEW) {
+		GOTO(out_root, nm_obj = ERR_PTR(-EROFS));
+	}
+
+again:
+	/* if loading index fails the first time, create new index */
+	if (create_new == NCFC_CREATE_NEW && rc != -ENOENT) {
+		CDEBUG(D_INFO, "removing old index, creating new one\n");
+		rc = local_object_unlink(env, dev, root_obj,
+					 LUSTRE_NODEMAP_NAME);
+		if (rc < 0) {
+			/* XXX not sure the best way to get obd name. */
+			CERROR("cannot destroy nodemap index: rc = %d\n",
+			       rc);
+			GOTO(out_root, nm_obj = ERR_PTR(rc));
+		}
+	}
+
+	nm_obj = local_index_find_or_create(env, los, root_obj,
+						LUSTRE_NODEMAP_NAME,
+						S_IFREG | S_IRUGO | S_IWUSR,
+						&dt_nodemap_features);
+	if (IS_ERR(nm_obj))
+		GOTO(out_root, nm_obj);
+
+	if (nm_obj->do_index_ops == NULL) {
+		rc = nm_obj->do_ops->do_index_try(env, nm_obj,
+						      &dt_nodemap_features);
+		/* even if loading from tgt fails, connecting to MGS will
+		 * rewrite the config
+		 */
+		if (rc < 0) {
+			dt_object_put(env, nm_obj);
+
+			if (create_new == NCFC_CREATE_NEW)
+				GOTO(out_root, nm_obj = ERR_PTR(rc));
+
+			CERROR("cannot load nodemap index from disk, creating "
+			       "new index: rc = %d\n", rc);
+			create_new = NCFC_CREATE_NEW;
+			goto again;
+		}
+	}
+
+out_root:
+	dt_object_put(env, root_obj);
+out:
+	return nm_obj;
+}
+
+static int nodemap_idx_insert(const struct lu_env *env,
 			      struct dt_object *idx,
 			      const struct nodemap_key *nk,
 			      const union nodemap_rec *nr)
 {
-	struct thandle		*th;
-	struct dt_device	*dev = lu2dt_dev(idx->do_lu.lo_dev);
-	int			 rc;
+	struct thandle *th;
+	struct dt_device *dev = lu2dt_dev(idx->do_lu.lo_dev);
+	int rc;
 
 	CLASSERT(sizeof(union nodemap_rec) == 32);
 
@@ -178,7 +273,7 @@ static int nodemap_idx_insert(struct lu_env *env,
 	dt_write_lock(env, idx, 0);
 
 	rc = dt_insert(env, idx, (const struct dt_rec *)nr,
-		       (const struct dt_key *)nk, th, 1);
+		       (const struct dt_key *)nk, th);
 
 	nodemap_inc_version(env, idx, th);
 	dt_write_unlock(env, idx);
@@ -188,7 +283,7 @@ out:
 	return rc;
 }
 
-static int nodemap_idx_update(struct lu_env *env,
+static int nodemap_idx_update(const struct lu_env *env,
 			      struct dt_object *idx,
 			      const struct nodemap_key *nk,
 			      const union nodemap_rec *nr)
@@ -226,7 +321,7 @@ static int nodemap_idx_update(struct lu_env *env,
 		GOTO(out_lock, rc);
 
 	rc = dt_insert(env, idx, (const struct dt_rec *)nr,
-		       (const struct dt_key *)nk, th, 1);
+		       (const struct dt_key *)nk, th);
 	if (rc != 0)
 		GOTO(out_lock, rc);
 
@@ -239,7 +334,7 @@ out:
 	return rc;
 }
 
-static int nodemap_idx_delete(struct lu_env *env,
+static int nodemap_idx_delete(const struct lu_env *env,
 			      struct dt_object *idx,
 			      const struct nodemap_key *nk,
 			      const union nodemap_rec *unused)
@@ -278,79 +373,59 @@ out:
 	return rc;
 }
 
-typedef int (*nm_idx_cb_t)(struct lu_env *env,
-			   struct dt_object *idx,
-			   const struct nodemap_key *nk,
-			   const union nodemap_rec *nr);
-
-/**
- * Iterates through all the registered nodemap_config_files and calls the
- * given callback with the ncf as a parameter, as well as the given key and rec.
- *
- * \param	cb_f		callback function to call
- * \param	nk		key of the record to act upon
- * \param	nr		record to act upon, NULL for the delete action
- */
-static int nodemap_idx_action(nm_idx_cb_t cb_f, struct nodemap_key *nk,
-			      union nodemap_rec *nr)
-{
-	struct nm_config_file	*ncf;
-	struct lu_env		 env;
-	int			 rc = 0;
-	int			 rc2 = 0;
-
-	rc = lu_env_init(&env, LCT_LOCAL);
-	if (rc != 0)
-		return rc;
-
-	mutex_lock(&ncf_list_lock);
-	list_for_each_entry(ncf, &ncf_list_head, ncf_list) {
-		rc2 = cb_f(&env, ncf->ncf_obj, nk, nr);
-		if (rc2 < 0) {
-			CWARN("%s: error writing to nodemap config: rc = %d\n",
-			      ncf->ncf_obj->do_lu.lo_dev->ld_obd->obd_name, rc);
-			rc = rc2;
-		}
-	}
-	mutex_unlock(&ncf_list_lock);
-	lu_env_fini(&env);
-
-	return 0;
-}
-
 enum nm_add_update {
 	NM_ADD = 0,
 	NM_UPDATE = 1,
 };
 
 static int nodemap_idx_nodemap_add_update(const struct lu_nodemap *nodemap,
+					  struct dt_object *idx,
 					  enum nm_add_update update)
 {
-	struct nodemap_key	 nk;
-	union nodemap_rec	 nr;
+	struct nodemap_key nk;
+	union nodemap_rec nr;
+	struct lu_env env;
 	int rc = 0;
 
 	ENTRY;
 
+	rc = lu_env_init(&env, LCT_LOCAL);
+	if (rc)
+		RETURN(rc);
+
 	nodemap_cluster_key_init(&nk, nodemap->nm_id);
 	nodemap_cluster_rec_init(&nr, nodemap);
 
 	if (update == NM_UPDATE)
-		rc = nodemap_idx_action(nodemap_idx_update, &nk, &nr);
+		rc = nodemap_idx_update(&env, idx, &nk, &nr);
 	else
-		rc = nodemap_idx_action(nodemap_idx_insert, &nk, &nr);
+		rc = nodemap_idx_insert(&env, idx, &nk, &nr);
+
+	lu_env_fini(&env);
 
 	RETURN(rc);
 }
 
 int nodemap_idx_nodemap_add(const struct lu_nodemap *nodemap)
 {
-	return nodemap_idx_nodemap_add_update(nodemap, NM_ADD);
+	if (nodemap_mgs_ncf == NULL) {
+		CERROR("cannot add nodemap config to non-existing MGS.\n");
+		return -EINVAL;
+	}
+
+	return nodemap_idx_nodemap_add_update(nodemap, nodemap_mgs_ncf->ncf_obj,
+					      NM_ADD);
 }
 
 int nodemap_idx_nodemap_update(const struct lu_nodemap *nodemap)
 {
-	return nodemap_idx_nodemap_add_update(nodemap, NM_UPDATE);
+	if (nodemap_mgs_ncf == NULL) {
+		CERROR("cannot add nodemap config to non-existing MGS.\n");
+		return -EINVAL;
+	}
+
+	return nodemap_idx_nodemap_add_update(nodemap, nodemap_mgs_ncf->ncf_obj,
+					      NM_UPDATE);
 }
 
 int nodemap_idx_nodemap_del(const struct lu_nodemap *nodemap)
@@ -361,17 +436,28 @@ int nodemap_idx_nodemap_del(const struct lu_nodemap *nodemap)
 	struct lu_nid_range	*range;
 	struct lu_nid_range	*range_temp;
 	struct nodemap_key	 nk;
+	struct lu_env		 env;
 	int			 rc = 0;
 	int			 rc2 = 0;
 
 	ENTRY;
 
+	if (nodemap_mgs_ncf == NULL) {
+		CERROR("cannot add nodemap config to non-existing MGS.\n");
+		return -EINVAL;
+	}
+
+	rc = lu_env_init(&env, LCT_LOCAL);
+	if (rc != 0)
+		RETURN(rc);
+
 	root = nodemap->nm_fs_to_client_uidmap;
 	nm_rbtree_postorder_for_each_entry_safe(idmap, temp, &root,
 						id_fs_to_client) {
 		nodemap_idmap_key_init(&nk, nodemap->nm_id, NODEMAP_UID,
 				       idmap->id_client);
-		rc2 = nodemap_idx_action(nodemap_idx_delete, &nk, NULL);
+		rc2 = nodemap_idx_delete(&env, nodemap_mgs_ncf->ncf_obj,
+					 &nk, NULL);
 		if (rc2 < 0)
 			rc = rc2;
 	}
@@ -381,7 +467,8 @@ int nodemap_idx_nodemap_del(const struct lu_nodemap *nodemap)
 						id_client_to_fs) {
 		nodemap_idmap_key_init(&nk, nodemap->nm_id, NODEMAP_GID,
 				       idmap->id_client);
-		rc2 = nodemap_idx_action(nodemap_idx_delete, &nk, NULL);
+		rc2 = nodemap_idx_delete(&env, nodemap_mgs_ncf->ncf_obj,
+					 &nk, NULL);
 		if (rc2 < 0)
 			rc = rc2;
 	}
@@ -389,16 +476,19 @@ int nodemap_idx_nodemap_del(const struct lu_nodemap *nodemap)
 	list_for_each_entry_safe(range, range_temp, &nodemap->nm_ranges,
 				 rn_list) {
 		nodemap_range_key_init(&nk, nodemap->nm_id, range->rn_id);
-		rc2 = nodemap_idx_action(nodemap_idx_delete, &nk, NULL);
+		rc2 = nodemap_idx_delete(&env, nodemap_mgs_ncf->ncf_obj,
+					 &nk, NULL);
 		if (rc2 < 0)
 			rc = rc2;
 	}
 
 	nodemap_cluster_key_init(&nk, nodemap->nm_id);
-	rc2 = nodemap_idx_action(nodemap_idx_delete, &nk, NULL);
+	rc2 = nodemap_idx_delete(&env, nodemap_mgs_ncf->ncf_obj, &nk, NULL);
 	if (rc2 < 0)
 		rc = rc2;
 
+	lu_env_fini(&env);
+
 	RETURN(rc);
 }
 
@@ -407,22 +497,50 @@ int nodemap_idx_range_add(const struct lu_nid_range *range,
 {
 	struct nodemap_key	 nk;
 	union nodemap_rec	 nr;
+	struct lu_env		 env;
+	int			 rc = 0;
 	ENTRY;
 
+	if (nodemap_mgs_ncf == NULL) {
+		CERROR("cannot add nodemap config to non-existing MGS.\n");
+		return -EINVAL;
+	}
+
+	rc = lu_env_init(&env, LCT_LOCAL);
+	if (rc != 0)
+		RETURN(rc);
+
 	nodemap_range_key_init(&nk, range->rn_nodemap->nm_id, range->rn_id);
 	nodemap_range_rec_init(&nr, nid);
 
-	RETURN(nodemap_idx_action(nodemap_idx_insert, &nk, &nr));
+	rc = nodemap_idx_insert(&env, nodemap_mgs_ncf->ncf_obj, &nk, &nr);
+	lu_env_fini(&env);
+
+	RETURN(rc);
 }
 
 int nodemap_idx_range_del(const struct lu_nid_range *range)
 {
 	struct nodemap_key	 nk;
+	struct lu_env		 env;
+	int			 rc = 0;
 	ENTRY;
 
+	if (nodemap_mgs_ncf == NULL) {
+		CERROR("cannot add nodemap config to non-existing MGS.\n");
+		return -EINVAL;
+	}
+
+	rc = lu_env_init(&env, LCT_LOCAL);
+	if (rc != 0)
+		RETURN(rc);
+
 	nodemap_range_key_init(&nk, range->rn_nodemap->nm_id, range->rn_id);
 
-	RETURN(nodemap_idx_action(nodemap_idx_delete, &nk, NULL));
+	rc = nodemap_idx_delete(&env, nodemap_mgs_ncf->ncf_obj, &nk, NULL);
+	lu_env_fini(&env);
+
+	RETURN(rc);
 }
 
 int nodemap_idx_idmap_add(const struct lu_nodemap *nodemap,
@@ -431,12 +549,26 @@ int nodemap_idx_idmap_add(const struct lu_nodemap *nodemap,
 {
 	struct nodemap_key	 nk;
 	union nodemap_rec	 nr;
+	struct lu_env		 env;
+	int			 rc = 0;
 	ENTRY;
 
+	if (nodemap_mgs_ncf == NULL) {
+		CERROR("cannot add nodemap config to non-existing MGS.\n");
+		return -EINVAL;
+	}
+
+	rc = lu_env_init(&env, LCT_LOCAL);
+	if (rc != 0)
+		RETURN(rc);
+
 	nodemap_idmap_key_init(&nk, nodemap->nm_id, id_type, map[0]);
 	nodemap_idmap_rec_init(&nr, map[1]);
 
-	RETURN(nodemap_idx_action(nodemap_idx_insert, &nk, &nr));
+	rc = nodemap_idx_insert(&env, nodemap_mgs_ncf->ncf_obj, &nk, &nr);
+	lu_env_fini(&env);
+
+	RETURN(rc);
 }
 
 int nodemap_idx_idmap_del(const struct lu_nodemap *nodemap,
@@ -444,26 +576,57 @@ int nodemap_idx_idmap_del(const struct lu_nodemap *nodemap,
 			  const u32 map[2])
 {
 	struct nodemap_key	 nk;
+	struct lu_env		 env;
+	int			 rc = 0;
 	ENTRY;
 
+	if (nodemap_mgs_ncf == NULL) {
+		CERROR("cannot add nodemap config to non-existing MGS.\n");
+		return -EINVAL;
+	}
+
+	rc = lu_env_init(&env, LCT_LOCAL);
+	if (rc != 0)
+		RETURN(rc);
+
 	nodemap_idmap_key_init(&nk, nodemap->nm_id, id_type, map[0]);
 
-	RETURN(nodemap_idx_action(nodemap_idx_delete, &nk, NULL));
+	rc = nodemap_idx_delete(&env, nodemap_mgs_ncf->ncf_obj, &nk, NULL);
+	lu_env_fini(&env);
+
+	RETURN(rc);
 }
 
 static int nodemap_idx_global_add_update(bool value, enum nm_add_update update)
 {
 	struct nodemap_key	 nk;
 	union nodemap_rec	 nr;
+	struct lu_env		 env;
+	int			 rc = 0;
 	ENTRY;
 
+	if (nodemap_mgs_ncf == NULL) {
+		CERROR("cannot add nodemap config to non-existing MGS.\n");
+		return -EINVAL;
+	}
+
+	rc = lu_env_init(&env, LCT_LOCAL);
+	if (rc != 0)
+		RETURN(rc);
+
 	nodemap_global_key_init(&nk);
 	nodemap_global_rec_init(&nr, value);
 
 	if (update == NM_UPDATE)
-		RETURN(nodemap_idx_action(nodemap_idx_update, &nk, &nr));
+		rc = nodemap_idx_update(&env, nodemap_mgs_ncf->ncf_obj,
+					&nk, &nr);
 	else
-		RETURN(nodemap_idx_action(nodemap_idx_insert, &nk, &nr));
+		rc = nodemap_idx_insert(&env, nodemap_mgs_ncf->ncf_obj,
+					&nk, &nr);
+
+	lu_env_fini(&env);
+
+	RETURN(rc);
 }
 
 int nodemap_idx_nodemap_activate(bool value)
@@ -471,6 +634,14 @@ int nodemap_idx_nodemap_activate(bool value)
 	return nodemap_idx_global_add_update(value, NM_UPDATE);
 }
 
+static enum nodemap_idx_type nodemap_get_key_type(const struct nodemap_key *key)
+{
+	u32			 nodemap_id;
+
+	nodemap_id = le32_to_cpu(key->nk_nodemap_id);
+	return nm_idx_get_type(nodemap_id);
+}
+
 /**
  * Process a key/rec pair and modify the new configuration.
  *
@@ -489,21 +660,26 @@ static int nodemap_process_keyrec(struct nodemap_config *config,
 				  const union nodemap_rec *rec,
 				  struct lu_nodemap **recent_nodemap)
 {
-	struct lu_nodemap	*nodemap = NULL;
-	enum nodemap_idx_type	 type;
-	enum nodemap_id_type	 id_type;
-	u8			 flags;
-	u32			 nodemap_id;
-	lnet_nid_t		 nid[2];
-	u32			 map[2];
-	int			 rc;
+	struct lu_nodemap *nodemap = NULL;
+	enum nodemap_idx_type type;
+	enum nodemap_id_type id_type;
+	u8 flags;
+	u32 nodemap_id;
+	lnet_nid_t nid[2];
+	u32 map[2];
+	int rc;
+
+	ENTRY;
 
 	CLASSERT(sizeof(union nodemap_rec) == 32);
 
 	nodemap_id = le32_to_cpu(key->nk_nodemap_id);
-	type = nm_idx_get_type(nodemap_id);
+	type = nodemap_get_key_type(key);
 	nodemap_id = nm_idx_set_type(nodemap_id, 0);
 
+	CDEBUG(D_INFO, "found config entry, nm_id %d type %d\n",
+	       nodemap_id, type);
+
 	/* find the correct nodemap in the load list */
 	if (type == NODEMAP_RANGE_IDX || type == NODEMAP_UIDMAP_IDX ||
 	    type == NODEMAP_GIDMAP_IDX) {
@@ -537,7 +713,9 @@ static int nodemap_process_keyrec(struct nodemap_config *config,
 			      " nodemap_id=%d. nodemap config file corrupt?\n",
 			      nodemap_id);
 		break;
-	case NODEMAP_CLUSTER_IDX:
+	case NODEMAP_CLUSTER_IDX: {
+		struct lu_nodemap *old_nm = NULL;
+
 		nodemap = cfs_hash_lookup(config->nmc_nodemap_hash,
 					  rec->ncr.ncr_name);
 		if (nodemap == NULL) {
@@ -572,6 +750,25 @@ static int nodemap_process_keyrec(struct nodemap_config *config,
 					flags & NM_FL_ALLOW_ROOT_ACCESS;
 		nodemap->nmf_trust_client_ids =
 					flags & NM_FL_TRUST_CLIENT_IDS;
+		nodemap->nmf_deny_unknown =
+					flags & NM_FL_DENY_UNKNOWN;
+		nodemap->nmf_map_uid_only =
+					flags & NM_FL_MAP_UID_ONLY;
+		nodemap->nmf_map_gid_only =
+					flags & NM_FL_MAP_GID_ONLY;
+		nodemap->nmf_enable_audit =
+					flags & NM_FL_ENABLE_AUDIT;
+
+		/* The fileset should be saved otherwise it will be empty
+		 * every time in case of "NODEMAP_CLUSTER_IDX". */
+		mutex_lock(&active_config_lock);
+		old_nm = nodemap_lookup(rec->ncr.ncr_name);
+		if (!IS_ERR(old_nm) && old_nm->nm_fileset[0] != '\0')
+			strlcpy(nodemap->nm_fileset, old_nm->nm_fileset,
+				sizeof(nodemap->nm_fileset));
+		mutex_unlock(&active_config_lock);
+		if (!IS_ERR(old_nm))
+			nodemap_putref(old_nm);
 
 		if (*recent_nodemap == NULL) {
 			*recent_nodemap = nodemap;
@@ -582,6 +779,7 @@ static int nodemap_process_keyrec(struct nodemap_config *config,
 		}
 		nodemap_putref(nodemap);
 		break;
+	}
 	case NODEMAP_RANGE_IDX:
 		nid[0] = le64_to_cpu(rec->nrr.nrr_start_nid);
 		nid[1] = le64_to_cpu(rec->nrr.nrr_end_nid);
@@ -612,23 +810,32 @@ static int nodemap_process_keyrec(struct nodemap_config *config,
 		CERROR("got keyrec pair for unknown type %d\n", type);
 		break;
 	}
+
 	rc = type;
 
+	EXIT;
+
 out:
 	return rc;
 }
 
+enum nm_config_passes {
+	NM_READ_CLUSTERS = 0,
+	NM_READ_ATTRIBUTES = 1,
+};
+
 static int nodemap_load_entries(const struct lu_env *env,
 				struct dt_object *nodemap_idx)
 {
-	const struct dt_it_ops  *iops;
-	struct dt_it            *it;
-	struct lu_nodemap	*recent_nodemap = NULL;
-	struct nodemap_config	*new_config = NULL;
-	u64			 hash = 0;
-	bool			 activate_nodemap = false;
-	bool			 loaded_global_idx = false;
-	int			 rc = 0;
+	const struct dt_it_ops *iops;
+	struct dt_it *it;
+	struct lu_nodemap *recent_nodemap = NULL;
+	struct nodemap_config *new_config = NULL;
+	u64 hash = 0;
+	bool activate_nodemap = false;
+	bool loaded_global_idx = false;
+	enum nm_config_passes cur_pass = NM_READ_CLUSTERS;
+	int rc = 0;
 
 	ENTRY;
 
@@ -640,54 +847,83 @@ static int nodemap_load_entries(const struct lu_env *env,
 		GOTO(out, rc = PTR_ERR(it));
 
 	rc = iops->load(env, it, hash);
+	if (rc < 0)
+		GOTO(out_iops_fini, rc);
+
+	/* rc == 0 means we need to advance to record */
 	if (rc == 0) {
 		rc = iops->next(env, it);
-		if (rc != 0)
-			GOTO(out_iops, rc = 0);
+
+		if (rc < 0)
+			GOTO(out_iops_put, rc);
+		/* rc > 0 is eof, will be checked in while below */
+	} else {
+		/* rc == 1, we found initial record and can process below */
+		rc = 0;
 	}
 
-	/* acquires active config lock */
 	new_config = nodemap_config_alloc();
-
 	if (IS_ERR(new_config)) {
 		rc = PTR_ERR(new_config);
 		new_config = NULL;
-		GOTO(out_lock, rc);
+		GOTO(out_iops_put, rc);
 	}
 
-	do {
+	/* rc > 0 is eof, check initial iops->next here as well */
+	while (rc == 0) {
 		struct nodemap_key *key;
 		union nodemap_rec rec;
+		enum nodemap_idx_type key_type;
 
 		key = (struct nodemap_key *)iops->key(env, it);
-		rc = iops->rec(env, it, (struct dt_rec *)&rec, 0);
-		if (rc != -ESTALE) {
-			if (rc != 0)
-				GOTO(out_lock, rc);
-			rc = nodemap_process_keyrec(new_config, key, &rec,
-						    &recent_nodemap);
-			if (rc < 0)
-				GOTO(out_lock, rc);
-			if (rc == NODEMAP_GLOBAL_IDX)
-				loaded_global_idx = true;
+		key_type = nodemap_get_key_type((struct nodemap_key *)key);
+		if ((cur_pass == NM_READ_CLUSTERS &&
+				key_type == NODEMAP_CLUSTER_IDX) ||
+		    (cur_pass == NM_READ_ATTRIBUTES &&
+				key_type != NODEMAP_CLUSTER_IDX &&
+				key_type != NODEMAP_EMPTY_IDX)) {
+			rc = iops->rec(env, it, (struct dt_rec *)&rec, 0);
+			if (rc != -ESTALE) {
+				if (rc != 0)
+					GOTO(out_nodemap_config, rc);
+				rc = nodemap_process_keyrec(new_config, key, &rec,
+							    &recent_nodemap);
+				if (rc < 0)
+					GOTO(out_nodemap_config, rc);
+				if (rc == NODEMAP_GLOBAL_IDX)
+					loaded_global_idx = true;
+			}
 		}
 
 		do
 			rc = iops->next(env, it);
 		while (rc == -ESTALE);
-	} while (rc == 0);
+
+		/* move to second pass */
+		if (rc > 0 && cur_pass == NM_READ_CLUSTERS) {
+			cur_pass = NM_READ_ATTRIBUTES;
+			rc = iops->load(env, it, 0);
+			if (rc == 0)
+				rc = iops->next(env, it);
+			else if (rc > 0)
+				rc = 0;
+			else
+				GOTO(out, rc);
+		}
+	}
 
 	if (rc > 0)
 		rc = 0;
 
-out_lock:
+out_nodemap_config:
 	if (rc != 0)
 		nodemap_config_dealloc(new_config);
 	else
 		/* creating new default needs to be done outside dt read lock */
 		activate_nodemap = true;
-out_iops:
+out_iops_put:
 	iops->put(env, it);
+out_iops_fini:
 	iops->fini(env, it);
 out:
 	dt_read_unlock(env, nodemap_idx);
@@ -707,14 +943,22 @@ out:
 			rc = PTR_ERR(new_config->nmc_default_nodemap);
 		} else {
 			rc = nodemap_idx_nodemap_add_update(
-					new_config->nmc_default_nodemap, 0);
+					new_config->nmc_default_nodemap,
+					nodemap_idx,
+					NM_ADD);
 			nodemap_putref(new_config->nmc_default_nodemap);
 		}
 	}
 
 	/* new nodemap config won't have an active/inactive record */
-	if (rc == 0 && loaded_global_idx == false)
-		rc = nodemap_idx_global_add_update(false, NM_ADD);
+	if (rc == 0 && loaded_global_idx == false) {
+		struct nodemap_key	 nk;
+		union nodemap_rec	 nr;
+
+		nodemap_global_key_init(&nk);
+		nodemap_global_rec_init(&nr, false);
+		rc = nodemap_idx_insert(env, nodemap_idx, &nk, &nr);
+	}
 
 	if (rc == 0)
 		nodemap_config_set_active(new_config);
@@ -725,6 +969,161 @@ out:
 }
 
 /**
+ * Step through active config and write to disk.
+ */
+struct dt_object *nodemap_save_config_cache(const struct lu_env *env,
+					    struct dt_device *dev,
+					    struct local_oid_storage *los)
+{
+	struct dt_object *o;
+	struct lu_nodemap *nodemap;
+	struct lu_nodemap *nm_tmp;
+	struct lu_nid_range *range;
+	struct lu_nid_range *range_temp;
+	struct lu_idmap *idmap;
+	struct lu_idmap *id_tmp;
+	struct rb_root root;
+	struct nodemap_key nk;
+	union nodemap_rec nr;
+	LIST_HEAD(nodemap_list_head);
+	int rc = 0, rc2;
+
+	ENTRY;
+
+	/* create a new index file to fill with active config */
+	o = nodemap_cache_find_create(env, dev, los, NCFC_CREATE_NEW);
+	if (IS_ERR(o))
+		RETURN(o);
+
+	mutex_lock(&active_config_lock);
+
+	/* convert hash to list so we don't spin */
+	cfs_hash_for_each_safe(active_config->nmc_nodemap_hash,
+			       nm_hash_list_cb, &nodemap_list_head);
+
+	list_for_each_entry_safe(nodemap, nm_tmp, &nodemap_list_head, nm_list) {
+		nodemap_cluster_key_init(&nk, nodemap->nm_id);
+		nodemap_cluster_rec_init(&nr, nodemap);
+
+		rc2 = nodemap_idx_insert(env, o, &nk, &nr);
+		if (rc2 < 0) {
+			rc = rc2;
+			continue;
+		}
+
+		down_read(&active_config->nmc_range_tree_lock);
+		list_for_each_entry_safe(range, range_temp, &nodemap->nm_ranges,
+					 rn_list) {
+			lnet_nid_t nid[2] = {
+				range->rn_node.in_extent.start,
+				range->rn_node.in_extent.end
+			};
+			nodemap_range_key_init(&nk, nodemap->nm_id,
+					       range->rn_id);
+			nodemap_range_rec_init(&nr, nid);
+			rc2 = nodemap_idx_insert(env, o, &nk, &nr);
+			if (rc2 < 0)
+				rc = rc2;
+		}
+		up_read(&active_config->nmc_range_tree_lock);
+
+		/* we don't need to take nm_idmap_lock because active config
+		 * lock prevents changes from happening to nodemaps
+		 */
+		root = nodemap->nm_client_to_fs_uidmap;
+		nm_rbtree_postorder_for_each_entry_safe(idmap, id_tmp, &root,
+							id_client_to_fs) {
+			nodemap_idmap_key_init(&nk, nodemap->nm_id, NODEMAP_UID,
+					       idmap->id_client);
+			nodemap_idmap_rec_init(&nr, idmap->id_fs);
+			rc2 = nodemap_idx_insert(env, o, &nk, &nr);
+			if (rc2 < 0)
+				rc = rc2;
+		}
+
+		root = nodemap->nm_client_to_fs_gidmap;
+		nm_rbtree_postorder_for_each_entry_safe(idmap, id_tmp, &root,
+							id_client_to_fs) {
+			nodemap_idmap_key_init(&nk, nodemap->nm_id, NODEMAP_GID,
+					       idmap->id_client);
+			nodemap_idmap_rec_init(&nr, idmap->id_fs);
+			rc2 = nodemap_idx_insert(env, o, &nk, &nr);
+			if (rc2 < 0)
+				rc = rc2;
+		}
+	}
+	nodemap_global_key_init(&nk);
+	nodemap_global_rec_init(&nr, active_config->nmc_nodemap_is_active);
+	rc2 = nodemap_idx_insert(env, o, &nk, &nr);
+	if (rc2 < 0)
+		rc = rc2;
+
+	mutex_unlock(&active_config_lock);
+
+	if (rc < 0) {
+		dt_object_put(env, o);
+		o = ERR_PTR(rc);
+	}
+
+	RETURN(o);
+}
+
+static void nodemap_save_all_caches(void)
+{
+	struct nm_config_file	*ncf;
+	struct lu_env		 env;
+	int			 rc = 0;
+
+	/* recreating nodemap cache requires fld_thread_key be in env */
+	rc = lu_env_init(&env, LCT_MD_THREAD | LCT_DT_THREAD | LCT_MG_THREAD);
+	if (rc != 0) {
+		CWARN("cannot init env for nodemap config: rc = %d\n", rc);
+		return;
+	}
+
+	mutex_lock(&ncf_list_lock);
+	list_for_each_entry(ncf, &ncf_list_head, ncf_list) {
+		struct dt_device *dev = lu2dt_dev(ncf->ncf_obj->do_lu.lo_dev);
+		struct obd_device *obd = ncf->ncf_obj->do_lu.lo_dev->ld_obd;
+		struct dt_object *o;
+
+		/* put current config file so save conf can rewrite it */
+		dt_object_put_nocache(&env, ncf->ncf_obj);
+		ncf->ncf_obj = NULL;
+
+		o = nodemap_save_config_cache(&env, dev, ncf->ncf_los);
+		if (IS_ERR(o))
+			CWARN("%s: error writing to nodemap config: rc = %d\n",
+			      obd->obd_name, rc);
+		else
+			ncf->ncf_obj = o;
+	}
+	mutex_unlock(&ncf_list_lock);
+
+	lu_env_fini(&env);
+}
+
+/* tracks if config still needs to be loaded, either from disk or network */
+static bool nodemap_config_loaded;
+static DEFINE_MUTEX(nodemap_config_loaded_lock);
+
+/**
+ * Ensures that configs loaded over the wire are prioritized over those loaded
+ * from disk.
+ *
+ * \param config	config to set as the active config
+ */
+void nodemap_config_set_active_mgc(struct nodemap_config *config)
+{
+	mutex_lock(&nodemap_config_loaded_lock);
+	nodemap_config_set_active(config);
+	nodemap_config_loaded = true;
+	nodemap_save_all_caches();
+	mutex_unlock(&nodemap_config_loaded_lock);
+}
+EXPORT_SYMBOL(nodemap_config_set_active_mgc);
+
+/**
  * Register a dt_object representing the config index file. This should be
  * called by targets in order to load the nodemap configuration from disk. The
  * dt_object should be created with local_index_find_or_create and the index
@@ -736,61 +1135,416 @@ out:
  * \retval	-ENOMEM		memory allocation failure
  * \retval	-ENOENT		error loading nodemap config
  * \retval	-EINVAL		error loading nodemap config
+ * \retval	-EEXIST		nodemap config already registered for MGS
  */
-struct nm_config_file *nm_config_file_register(const struct lu_env *env,
-					       struct dt_object *obj)
+struct nm_config_file *nm_config_file_register_mgs(const struct lu_env *env,
+						   struct dt_object *obj,
+						   struct local_oid_storage *los)
 {
 	struct nm_config_file *ncf;
-	bool load_entries = false;
-	int rc;
+	int rc = 0;
 	ENTRY;
 
+	if (nodemap_mgs_ncf != NULL)
+		GOTO(out, ncf = ERR_PTR(-EEXIST));
+
 	OBD_ALLOC_PTR(ncf);
 	if (ncf == NULL)
-		RETURN(ERR_PTR(-ENOMEM));
+		GOTO(out, ncf = ERR_PTR(-ENOMEM));
+
+	/* if loading from cache, prevent activation of MGS config until cache
+	 * loading is done, so disk config is overwritten by MGS config.
+	 */
+	mutex_lock(&nodemap_config_loaded_lock);
+	rc = nodemap_load_entries(env, obj);
+	if (!rc)
+		nodemap_config_loaded = true;
+	mutex_unlock(&nodemap_config_loaded_lock);
+
+	if (rc) {
+		OBD_FREE_PTR(ncf);
+		GOTO(out, ncf = ERR_PTR(rc));
+	}
+
+	lu_object_get(&obj->do_lu);
 
 	ncf->ncf_obj = obj;
-	mutex_lock(&ncf_list_lock);
+	ncf->ncf_los = los;
 
-	/* if this is first config file, we load it from disk */
-	if (list_empty(&ncf_list_head))
-		load_entries = true;
+	nodemap_mgs_ncf = ncf;
 
+out:
+	return ncf;
+}
+EXPORT_SYMBOL(nm_config_file_register_mgs);
+
+struct nm_config_file *nm_config_file_register_tgt(const struct lu_env *env,
+						   struct dt_device *dev,
+						   struct local_oid_storage *los)
+{
+	struct nm_config_file *ncf;
+	struct dt_object *config_obj = NULL;
+	int rc = 0;
+
+	OBD_ALLOC_PTR(ncf);
+	if (ncf == NULL)
+		RETURN(ERR_PTR(-ENOMEM));
+
+	/* don't load from cache if config already loaded */
+	mutex_lock(&nodemap_config_loaded_lock);
+	if (!nodemap_config_loaded) {
+		config_obj = nodemap_cache_find_create(env, dev, los, 0);
+		if (IS_ERR(config_obj))
+			rc = PTR_ERR(config_obj);
+		else
+			rc = nodemap_load_entries(env, config_obj);
+
+		if (!rc)
+			nodemap_config_loaded = true;
+	}
+	mutex_unlock(&nodemap_config_loaded_lock);
+	if (rc)
+		GOTO(out_ncf, rc);
+
+	/* sync on disk caches w/ loaded config in memory, ncf_obj may change */
+	if (!config_obj) {
+		config_obj = nodemap_save_config_cache(env, dev, los);
+		if (IS_ERR(config_obj))
+			GOTO(out_ncf, rc = PTR_ERR(config_obj));
+	}
+
+	ncf->ncf_obj = config_obj;
+	ncf->ncf_los = los;
+
+	mutex_lock(&ncf_list_lock);
 	list_add(&ncf->ncf_list, &ncf_list_head);
 	mutex_unlock(&ncf_list_lock);
 
-	if (load_entries) {
-		rc = nodemap_load_entries(env, obj);
-		if (rc < 0) {
-			mutex_lock(&ncf_list_lock);
-			list_del(&ncf->ncf_list);
-			mutex_unlock(&ncf_list_lock);
-			OBD_FREE_PTR(ncf);
-			RETURN(ERR_PTR(rc));
-		}
+out_ncf:
+	if (rc) {
+		OBD_FREE_PTR(ncf);
+		RETURN(ERR_PTR(rc));
 	}
 
 	RETURN(ncf);
 }
-EXPORT_SYMBOL(nm_config_file_register);
+EXPORT_SYMBOL(nm_config_file_register_tgt);
 
 /**
  * Deregister a nm_config_file. Should be called by targets during cleanup.
  *
  * \param ncf	config file to deregister
  */
-void nm_config_file_deregister(const struct lu_env *env,
-			       struct nm_config_file *ncf)
+void nm_config_file_deregister_mgs(const struct lu_env *env,
+				   struct nm_config_file *ncf)
 {
 	ENTRY;
+	LASSERT(nodemap_mgs_ncf == ncf);
 
-	lu_object_put(env, &ncf->ncf_obj->do_lu);
+	nodemap_mgs_ncf = NULL;
+	if (ncf->ncf_obj)
+		dt_object_put(env, ncf->ncf_obj);
+
+	OBD_FREE_PTR(ncf);
+
+	EXIT;
+}
+EXPORT_SYMBOL(nm_config_file_deregister_mgs);
+
+void nm_config_file_deregister_tgt(const struct lu_env *env,
+				   struct nm_config_file *ncf)
+{
+	ENTRY;
+
+	if (ncf == NULL)
+		return;
 
 	mutex_lock(&ncf_list_lock);
 	list_del(&ncf->ncf_list);
 	mutex_unlock(&ncf_list_lock);
+
+	if (ncf->ncf_obj)
+		dt_object_put(env, ncf->ncf_obj);
+
 	OBD_FREE_PTR(ncf);
 
 	EXIT;
 }
-EXPORT_SYMBOL(nm_config_file_deregister);
+EXPORT_SYMBOL(nm_config_file_deregister_tgt);
+
+int nodemap_process_idx_pages(struct nodemap_config *config, union lu_page *lip,
+			      struct lu_nodemap **recent_nodemap)
+{
+	struct nodemap_key *key;
+	union nodemap_rec *rec;
+	char *entry;
+	int j;
+	int k;
+	int rc = 0;
+	int size = dt_nodemap_features.dif_keysize_max +
+		   dt_nodemap_features.dif_recsize_max;
+	ENTRY;
+
+	for (j = 0; j < LU_PAGE_COUNT; j++) {
+		if (lip->lp_idx.lip_magic != LIP_MAGIC)
+			return -EINVAL;
+
+		/* get and process keys and records from page */
+		for (k = 0; k < lip->lp_idx.lip_nr; k++) {
+			entry = lip->lp_idx.lip_entries + k * size;
+			key = (struct nodemap_key *)entry;
+
+			entry += dt_nodemap_features.dif_keysize_max;
+			rec = (union nodemap_rec *)entry;
+
+			rc = nodemap_process_keyrec(config, key, rec,
+						    recent_nodemap);
+			if (rc < 0)
+				return rc;
+		}
+		lip++;
+	}
+
+	EXIT;
+	return 0;
+}
+EXPORT_SYMBOL(nodemap_process_idx_pages);
+
+static int nodemap_page_build(const struct lu_env *env, union lu_page *lp,
+			      size_t nob, const struct dt_it_ops *iops,
+			      struct dt_it *it, __u32 attr, void *arg)
+{
+	struct idx_info *ii = (struct idx_info *)arg;
+	struct lu_idxpage *lip = &lp->lp_idx;
+	char *entry;
+	size_t size = ii->ii_keysize + ii->ii_recsize;
+	int rc;
+	ENTRY;
+
+	if (nob < LIP_HDR_SIZE)
+		return -EINVAL;
+
+	/* initialize the header of the new container */
+	memset(lip, 0, LIP_HDR_SIZE);
+	lip->lip_magic = LIP_MAGIC;
+	nob           -= LIP_HDR_SIZE;
+
+	entry = lip->lip_entries;
+	do {
+		char		*tmp_entry = entry;
+		struct dt_key	*key;
+		__u64		hash;
+		enum nodemap_idx_type key_type;
+
+		/* fetch 64-bit hash value */
+		hash = iops->store(env, it);
+		ii->ii_hash_end = hash;
+
+		if (OBD_FAIL_CHECK(OBD_FAIL_OBD_IDX_READ_BREAK)) {
+			if (lip->lip_nr != 0)
+				GOTO(out, rc = 0);
+		}
+
+		if (nob < size) {
+			if (lip->lip_nr == 0)
+				GOTO(out, rc = -EINVAL);
+			GOTO(out, rc = 0);
+		}
+
+		key = iops->key(env, it);
+		key_type = nodemap_get_key_type((struct nodemap_key *)key);
+
+		/* on the first pass, get only the cluster types. On second
+		 * pass, get all the rest */
+		if ((ii->ii_attrs == NM_READ_CLUSTERS &&
+				key_type == NODEMAP_CLUSTER_IDX) ||
+		    (ii->ii_attrs == NM_READ_ATTRIBUTES &&
+				key_type != NODEMAP_CLUSTER_IDX &&
+				key_type != NODEMAP_EMPTY_IDX)) {
+			memcpy(tmp_entry, key, ii->ii_keysize);
+			tmp_entry += ii->ii_keysize;
+
+			/* and finally the record */
+			rc = iops->rec(env, it, (struct dt_rec *)tmp_entry,
+				       attr);
+			if (rc != -ESTALE) {
+				if (rc != 0)
+					GOTO(out, rc);
+
+				/* hash/key/record successfully copied! */
+				lip->lip_nr++;
+				if (unlikely(lip->lip_nr == 1 &&
+				    ii->ii_count == 0))
+					ii->ii_hash_start = hash;
+
+				entry = tmp_entry + ii->ii_recsize;
+				nob -= size;
+			}
+		}
+
+		/* move on to the next record */
+		do {
+			rc = iops->next(env, it);
+		} while (rc == -ESTALE);
+
+		/* move to second pass */
+		if (rc > 0 && ii->ii_attrs == NM_READ_CLUSTERS) {
+			ii->ii_attrs = NM_READ_ATTRIBUTES;
+			rc = iops->load(env, it, 0);
+			if (rc == 0)
+				rc = iops->next(env, it);
+			else if (rc > 0)
+				rc = 0;
+			else
+				GOTO(out, rc);
+		}
+
+	} while (rc == 0);
+
+	GOTO(out, rc);
+out:
+	if (rc >= 0 && lip->lip_nr > 0)
+		/* one more container */
+		ii->ii_count++;
+	if (rc > 0)
+		/* no more entries */
+		ii->ii_hash_end = II_END_OFF;
+	return rc;
+}
+
+
+int nodemap_index_read(struct lu_env *env,
+		       struct nm_config_file *ncf,
+		       struct idx_info *ii,
+		       const struct lu_rdpg *rdpg)
+{
+	struct dt_object	*nodemap_idx = ncf->ncf_obj;
+	__u64			 version;
+	int			 rc = 0;
+
+	ii->ii_keysize = dt_nodemap_features.dif_keysize_max;
+	ii->ii_recsize = dt_nodemap_features.dif_recsize_max;
+
+	dt_read_lock(env, nodemap_idx, 0);
+	version = dt_version_get(env, nodemap_idx);
+	if (rdpg->rp_hash != 0 && ii->ii_version != version) {
+		CDEBUG(D_INFO, "nodemap config changed inflight, old %llu, new %llu\n",
+		       ii->ii_version,
+		       version);
+		ii->ii_hash_end = 0;
+	} else {
+		rc = dt_index_walk(env, nodemap_idx, rdpg, nodemap_page_build,
+				   ii);
+		CDEBUG(D_INFO, "walked index, hashend %llx\n", ii->ii_hash_end);
+	}
+
+	if (rc >= 0)
+		ii->ii_version = version;
+
+	dt_read_unlock(env, nodemap_idx);
+	return rc;
+}
+EXPORT_SYMBOL(nodemap_index_read);
+
+/**
+ * Returns the current nodemap configuration to MGC by walking the nodemap
+ * config index and storing it in the response buffer.
+ *
+ * \param	req		incoming MGS_CONFIG_READ request
+ * \retval	0		success
+ * \retval	-EINVAL		malformed request
+ * \retval	-ENOTCONN	client evicted/reconnected already
+ * \retval	-ETIMEDOUT	client timeout or network error
+ * \retval	-ENOMEM
+ */
+int nodemap_get_config_req(struct obd_device *mgs_obd,
+			   struct ptlrpc_request *req)
+{
+	struct mgs_config_body *body;
+	struct mgs_config_res *res;
+	struct lu_rdpg rdpg;
+	struct idx_info nodemap_ii;
+	struct ptlrpc_bulk_desc *desc;
+	struct l_wait_info lwi;
+	struct tg_export_data *rqexp_ted = &req->rq_export->exp_target_data;
+	int i;
+	int page_count;
+	int bytes = 0;
+	int rc = 0;
+
+	body = req_capsule_client_get(&req->rq_pill, &RMF_MGS_CONFIG_BODY);
+	if (!body)
+		RETURN(-EINVAL);
+
+	if (body->mcb_type != CONFIG_T_NODEMAP)
+		RETURN(-EINVAL);
+
+	rdpg.rp_count = (body->mcb_units << body->mcb_bits);
+	rdpg.rp_npages = (rdpg.rp_count + PAGE_SIZE - 1) >>
+		PAGE_SHIFT;
+	if (rdpg.rp_npages > PTLRPC_MAX_BRW_PAGES)
+		RETURN(-EINVAL);
+
+	CDEBUG(D_INFO, "reading nodemap log, name '%s', size = %u\n",
+	       body->mcb_name, rdpg.rp_count);
+
+	/* allocate pages to store the containers */
+	OBD_ALLOC(rdpg.rp_pages, sizeof(*rdpg.rp_pages) * rdpg.rp_npages);
+	if (rdpg.rp_pages == NULL)
+		RETURN(-ENOMEM);
+	for (i = 0; i < rdpg.rp_npages; i++) {
+		rdpg.rp_pages[i] = alloc_page(GFP_NOFS);
+		if (rdpg.rp_pages[i] == NULL)
+			GOTO(out, rc = -ENOMEM);
+	}
+
+	rdpg.rp_hash = body->mcb_offset;
+	nodemap_ii.ii_magic = IDX_INFO_MAGIC;
+	nodemap_ii.ii_flags = II_FL_NOHASH;
+	nodemap_ii.ii_version = rqexp_ted->ted_nodemap_version;
+	nodemap_ii.ii_attrs = body->mcb_nm_cur_pass;
+
+	bytes = nodemap_index_read(req->rq_svc_thread->t_env,
+				   mgs_obd->u.obt.obt_nodemap_config_file,
+				   &nodemap_ii, &rdpg);
+	if (bytes < 0)
+		GOTO(out, rc = bytes);
+
+	rqexp_ted->ted_nodemap_version = nodemap_ii.ii_version;
+
+	res = req_capsule_server_get(&req->rq_pill, &RMF_MGS_CONFIG_RES);
+	if (res == NULL)
+		GOTO(out, rc = -EINVAL);
+	res->mcr_offset = nodemap_ii.ii_hash_end;
+	res->mcr_nm_cur_pass = nodemap_ii.ii_attrs;
+
+	page_count = (bytes + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	LASSERT(page_count <= rdpg.rp_count);
+	desc = ptlrpc_prep_bulk_exp(req, page_count, 1,
+				    PTLRPC_BULK_PUT_SOURCE |
+					PTLRPC_BULK_BUF_KIOV,
+				    MGS_BULK_PORTAL,
+				    &ptlrpc_bulk_kiov_pin_ops);
+	if (desc == NULL)
+		GOTO(out, rc = -ENOMEM);
+
+	for (i = 0; i < page_count && bytes > 0; i++) {
+		ptlrpc_prep_bulk_page_pin(desc, rdpg.rp_pages[i], 0,
+					  min_t(int, bytes, PAGE_SIZE));
+		bytes -= PAGE_SIZE;
+	}
+
+	rc = target_bulk_io(req->rq_export, desc, &lwi);
+	ptlrpc_free_bulk(desc);
+
+out:
+	if (rdpg.rp_pages != NULL) {
+		for (i = 0; i < rdpg.rp_npages; i++)
+			if (rdpg.rp_pages[i] != NULL)
+				__free_page(rdpg.rp_pages[i]);
+		OBD_FREE(rdpg.rp_pages,
+			 rdpg.rp_npages * sizeof(rdpg.rp_pages[0]));
+	}
+	return rc;
+}
+EXPORT_SYMBOL(nodemap_get_config_req);