util: rewrite dlinklist.h so that DLIST_ADD_END() is O(1)
[ira/wip.git] / source4 / dsdb / samdb / ldb_modules / repl_meta_data.c
index df5ae1a1c69f97854a4597cc7069d34f8ed0ba4a..67d7094d4c890e7c9bc8f8889b0b2b628c51727d 100644 (file)
 #include "param/param.h"
 #include "libcli/security/dom_sid.h"
 #include "lib/util/dlinklist.h"
+#include "dsdb/samdb/ldb_modules/util.h"
+#include "lib/util/binsearch.h"
+#include "libcli/security/security.h"
+
+#define W2K3_LINKED_ATTRIBUTES 1
 
 struct replmd_private {
        TALLOC_CTX *la_ctx;
        struct la_entry *la_list;
-       uint32_t num_ncs;
+       TALLOC_CTX *bl_ctx;
+       struct la_backlink *la_backlinks;
        struct nc_entry {
+               struct nc_entry *prev, *next;
                struct ldb_dn *dn;
-               struct GUID guid;
                uint64_t mod_usn;
+               uint64_t mod_usn_urgent;
        } *ncs;
 };
 
@@ -68,17 +75,80 @@ struct replmd_replicated_request {
 
        const struct dsdb_schema *schema;
 
-       struct dsdb_extended_replicated_objects *objs;
-
        /* the controls we pass down */
        struct ldb_control **controls;
 
+       /* details for the mode where we apply a bunch of inbound replication meessages */
+       bool apply_mode;
        uint32_t index_current;
+       struct dsdb_extended_replicated_objects *objs;
 
        struct ldb_message *search_msg;
+
+       uint64_t seq_num;
+       bool is_urgent;
+};
+
+enum urgent_situation {
+       REPL_URGENT_ON_CREATE = 1,
+       REPL_URGENT_ON_UPDATE = 3, /* activated on creating as well*/
+       REPL_URGENT_ON_DELETE = 4
 };
 
 
+static const struct {
+       const char *update_name;
+       enum urgent_situation repl_situation;
+} urgent_objects[] = {
+               {"nTDSDSA", (REPL_URGENT_ON_CREATE | REPL_URGENT_ON_DELETE)},
+               {"crossRef", (REPL_URGENT_ON_CREATE | REPL_URGENT_ON_DELETE)},
+               {"attributeSchema", REPL_URGENT_ON_UPDATE},
+               {"classSchema", REPL_URGENT_ON_UPDATE},
+               {"secret", REPL_URGENT_ON_UPDATE},
+               {"rIDManager", REPL_URGENT_ON_UPDATE},
+               {NULL, 0}
+};
+
+/* Attributes looked for when updating or deleting, to check for a urgent replication needed */
+static const char *urgent_attrs[] = {
+               "lockoutTime",
+               "pwdLastSet",
+               "userAccountControl",
+               NULL
+};
+
+
+static bool replmd_check_urgent_objectclass(const struct ldb_message_element *objectclass_el,
+                                       enum urgent_situation situation)
+{
+       int i, j;
+       for (i=0; urgent_objects[i].update_name; i++) {
+
+               if ((situation & urgent_objects[i].repl_situation) == 0) {
+                       continue;
+               }
+
+               for (j=0; j<objectclass_el->num_values; j++) {
+                       const struct ldb_val *v = &objectclass_el->values[j];
+                       if (ldb_attr_cmp((const char *)v->data, urgent_objects[i].update_name) == 0) {
+                               return true;
+                       }
+               }
+       }
+       return false;
+}
+
+static bool replmd_check_urgent_attribute(const struct ldb_message_element *el)
+{
+       if (ldb_attr_in_list(urgent_attrs, el->name)) {
+               return true;
+       }
+       return false;
+}
+
+
+static int replmd_replicated_apply_next(struct replmd_replicated_request *ar);
+
 /*
   initialise the module
   allocate the private structure and build the list
@@ -99,131 +169,272 @@ static int replmd_init(struct ldb_module *module)
        return ldb_next_init(module);
 }
 
-
-static int nc_compare(struct nc_entry *n1, struct nc_entry *n2)
+/*
+  cleanup our per-transaction contexts
+ */
+static void replmd_txn_cleanup(struct replmd_private *replmd_private)
 {
-       return ldb_dn_compare(n1->dn, n2->dn);
+       talloc_free(replmd_private->la_ctx);
+       replmd_private->la_list = NULL;
+       replmd_private->la_ctx = NULL;
+
+       talloc_free(replmd_private->bl_ctx);
+       replmd_private->la_backlinks = NULL;
+       replmd_private->bl_ctx = NULL;
 }
 
+
+struct la_backlink {
+       struct la_backlink *next, *prev;
+       const char *attr_name;
+       struct GUID forward_guid, target_guid;
+       bool active;
+};
+
 /*
-  build the list of partition DNs for use by replmd_notify()
+  process a backlinks we accumulated during a transaction, adding and
+  deleting the backlinks from the target objects
  */
-static int replmd_load_NCs(struct ldb_module *module)
+static int replmd_process_backlink(struct ldb_module *module, struct la_backlink *bl)
 {
-       const char *attrs[] = { "namingContexts", NULL };
-       struct ldb_result *res = NULL;
-       int i, ret;
-       TALLOC_CTX *tmp_ctx;
-       struct ldb_context *ldb;
-       struct ldb_message_element *el;
-       struct replmd_private *replmd_private = 
-               talloc_get_type(ldb_module_get_private(module), struct replmd_private);
+       struct ldb_dn *target_dn, *source_dn;
+       int ret;
+       struct ldb_context *ldb = ldb_module_get_ctx(module);
+       struct ldb_message *msg;
+       TALLOC_CTX *tmp_ctx = talloc_new(bl);
+       char *dn_string;
 
-       if (replmd_private->ncs != NULL) {
-               return LDB_SUCCESS;
+       /*
+         - find DN of target
+         - find DN of source
+         - construct ldb_message
+              - either an add or a delete
+        */
+       ret = dsdb_module_dn_by_guid(module, tmp_ctx, &bl->target_guid, &target_dn);
+       if (ret != LDB_SUCCESS) {
+               ldb_asprintf_errstring(ldb, "Failed to find target DN for linked attribute with GUID %s\n",
+                                      GUID_string(bl, &bl->target_guid));
+               talloc_free(tmp_ctx);
+               return ret;
        }
 
-       ldb = ldb_module_get_ctx(module);
-       tmp_ctx = talloc_new(module);
-
-       /* load the list of naming contexts */
-       ret = ldb_search(ldb, tmp_ctx, &res, ldb_dn_new(tmp_ctx, ldb, ""), 
-                        LDB_SCOPE_BASE, attrs, NULL);
-       if (ret != LDB_SUCCESS ||
-           res->count != 1) {
-               DEBUG(0,(__location__ ": Failed to load rootDSE\n"));
-               return LDB_ERR_OPERATIONS_ERROR;
+       ret = dsdb_module_dn_by_guid(module, tmp_ctx, &bl->forward_guid, &source_dn);
+       if (ret != LDB_SUCCESS) {
+               ldb_asprintf_errstring(ldb, "Failed to find source DN for linked attribute with GUID %s\n",
+                                      GUID_string(bl, &bl->forward_guid));
+               talloc_free(tmp_ctx);
+               return ret;
        }
 
-       el = ldb_msg_find_element(res->msgs[0], "namingContexts");
-       if (el == NULL) {
-               DEBUG(0,(__location__ ": Failed to load namingContexts\n"));
-               return LDB_ERR_OPERATIONS_ERROR;                
+       msg = ldb_msg_new(tmp_ctx);
+       if (msg == NULL) {
+               ldb_module_oom(module);
+               talloc_free(tmp_ctx);
+               return LDB_ERR_OPERATIONS_ERROR;
        }
 
-       replmd_private->num_ncs = el->num_values;
-       replmd_private->ncs = talloc_array(replmd_private, struct nc_entry, 
-                                          replmd_private->num_ncs);
-       if (replmd_private->ncs == NULL) {
-               ldb_oom(ldb);
+       /* construct a ldb_message for adding/deleting the backlink */
+       msg->dn = target_dn;
+       dn_string = ldb_dn_get_extended_linearized(tmp_ctx, source_dn, 1);
+       if (!dn_string) {
+               ldb_module_oom(module);
+               talloc_free(tmp_ctx);
                return LDB_ERR_OPERATIONS_ERROR;
        }
+       ret = ldb_msg_add_steal_string(msg, bl->attr_name, dn_string);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
+               return ret;
+       }
+       msg->elements[0].flags = bl->active?LDB_FLAG_MOD_ADD:LDB_FLAG_MOD_DELETE;
 
-       for (i=0; i<replmd_private->num_ncs; i++) {
-               replmd_private->ncs[i].dn = 
-                       ldb_dn_from_ldb_val(replmd_private->ncs, 
-                                           ldb, &el->values[i]);
-               replmd_private->ncs[i].mod_usn = 0;
+       ret = dsdb_module_modify(module, msg, 0);
+       if (ret != LDB_SUCCESS) {
+               ldb_asprintf_errstring(ldb, "Failed to %s backlink from %s to %s - %s",
+                                      bl->active?"add":"remove",
+                                      ldb_dn_get_linearized(source_dn),
+                                      ldb_dn_get_linearized(target_dn),
+                                      ldb_errstring(ldb));
+               talloc_free(tmp_ctx);
+               return ret;
        }
+       talloc_free(tmp_ctx);
+       return ret;
+}
 
-       talloc_free(res);
+/*
+  add a backlink to the list of backlinks to add/delete in the prepare
+  commit
+ */
+static int replmd_add_backlink(struct ldb_module *module, const struct dsdb_schema *schema,
+                              struct GUID *forward_guid, struct GUID *target_guid,
+                              bool active, const struct dsdb_attribute *schema_attr, bool immediate)
+{
+       const struct dsdb_attribute *target_attr;
+       struct la_backlink *bl;
+       struct replmd_private *replmd_private =
+               talloc_get_type_abort(ldb_module_get_private(module), struct replmd_private);
 
-       /* now find the GUIDs of each of those DNs */
-       for (i=0; i<replmd_private->num_ncs; i++) {
-               const char *attrs2[] = { "objectGUID", NULL };
-               ret = ldb_search(ldb, tmp_ctx, &res, replmd_private->ncs[i].dn,
-                                LDB_SCOPE_BASE, attrs2, NULL);
-               if (ret != LDB_SUCCESS ||
-                   res->count != 1) {
-                       /* this happens when the schema is first being
-                          setup */
-                       talloc_free(replmd_private->ncs);
-                       replmd_private->ncs = NULL;
-                       replmd_private->num_ncs = 0;
-                       talloc_free(tmp_ctx);
+       target_attr = dsdb_attribute_by_linkID(schema, schema_attr->linkID ^ 1);
+       if (!target_attr) {
+               /*
+                * windows 2003 has a broken schema where the
+                * definition of msDS-IsDomainFor is missing (which is
+                * supposed to be the backlink of the
+                * msDS-HasDomainNCs attribute
+                */
+               return LDB_SUCCESS;
+       }
+
+       /* see if its already in the list */
+       for (bl=replmd_private->la_backlinks; bl; bl=bl->next) {
+               if (GUID_equal(forward_guid, &bl->forward_guid) &&
+                   GUID_equal(target_guid, &bl->target_guid) &&
+                   (target_attr->lDAPDisplayName == bl->attr_name ||
+                    strcmp(target_attr->lDAPDisplayName, bl->attr_name) == 0)) {
+                       break;
+               }
+       }
+
+       if (bl) {
+               /* we found an existing one */
+               if (bl->active == active) {
                        return LDB_SUCCESS;
                }
-               replmd_private->ncs[i].guid = 
-                       samdb_result_guid(res->msgs[0], "objectGUID");
-               talloc_free(res);
-       }       
+               DLIST_REMOVE(replmd_private->la_backlinks, bl);
+               talloc_free(bl);
+               return LDB_SUCCESS;
+       }
+
+       if (replmd_private->bl_ctx == NULL) {
+               replmd_private->bl_ctx = talloc_new(replmd_private);
+               if (replmd_private->bl_ctx == NULL) {
+                       ldb_module_oom(module);
+                       return LDB_ERR_OPERATIONS_ERROR;
+               }
+       }
+
+       /* its a new one */
+       bl = talloc(replmd_private->bl_ctx, struct la_backlink);
+       if (bl == NULL) {
+               ldb_module_oom(module);
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
 
-       /* sort the NCs into order, most to least specific */
-       qsort(replmd_private->ncs, replmd_private->num_ncs,
-             sizeof(replmd_private->ncs[0]), QSORT_CAST nc_compare);
+       bl->attr_name = target_attr->lDAPDisplayName;
+       bl->forward_guid = *forward_guid;
+       bl->target_guid = *target_guid;
+       bl->active = active;
+
+       /* the caller may ask for this backlink to be processed
+          immediately */
+       if (immediate) {
+               int ret = replmd_process_backlink(module, bl);
+               talloc_free(bl);
+               return ret;
+       }
+
+       DLIST_ADD(replmd_private->la_backlinks, bl);
 
-       
-       talloc_free(tmp_ctx);
-       
        return LDB_SUCCESS;
 }
 
 
 /*
+ * Callback for most write operations in this module:
+ * 
  * notify the repl task that a object has changed. The notifies are
  * gathered up in the replmd_private structure then written to the
  * @REPLCHANGED object in each partition during the prepare_commit
  */
-static int replmd_notify(struct ldb_module *module, struct ldb_dn *dn, uint64_t uSN)
+static int replmd_op_callback(struct ldb_request *req, struct ldb_reply *ares)
 {
-       int ret, i;
+       int ret;
+       struct replmd_replicated_request *ac = 
+               talloc_get_type_abort(req->context, struct replmd_replicated_request);
        struct replmd_private *replmd_private = 
-               talloc_get_type(ldb_module_get_private(module), struct replmd_private);
+               talloc_get_type_abort(ldb_module_get_private(ac->module), struct replmd_private);
+       struct nc_entry *modified_partition;
+       struct ldb_control *partition_ctrl;
+       const struct dsdb_control_current_partition *partition;
 
-       ret = replmd_load_NCs(module);
-       if (ret != LDB_SUCCESS) {
-               return ret;
-       }
-       if (replmd_private->num_ncs == 0) {
-               return LDB_SUCCESS;
+       struct ldb_control **controls;
+
+       partition_ctrl = ldb_reply_get_control(ares, DSDB_CONTROL_CURRENT_PARTITION_OID);
+
+       /* Remove the 'partition' control from what we pass up the chain */
+       controls = controls_except_specified(ares->controls, ares, partition_ctrl);
+
+       if (ares->error != LDB_SUCCESS) {
+               return ldb_module_done(ac->req, controls,
+                                       ares->response, ares->error);
        }
 
-       for (i=0; i<replmd_private->num_ncs; i++) {
-               if (ldb_dn_compare_base(replmd_private->ncs[i].dn, dn) == 0) {
-                       break;
-               }
+       if (ares->type != LDB_REPLY_DONE) {
+               ldb_set_errstring(ldb_module_get_ctx(ac->module), "Invalid reply type for notify\n!");
+               return ldb_module_done(ac->req, NULL,
+                                      NULL, LDB_ERR_OPERATIONS_ERROR);
        }
-       if (i == replmd_private->num_ncs) {
-               DEBUG(0,(__location__ ": DN not within known NCs '%s'\n", 
-                        ldb_dn_get_linearized(dn)));
-               return LDB_ERR_OPERATIONS_ERROR;
+
+       if (!partition_ctrl) {
+               ldb_set_errstring(ldb_module_get_ctx(ac->module),"No partition control on reply");
+               return ldb_module_done(ac->req, NULL,
+                                      NULL, LDB_ERR_OPERATIONS_ERROR);
        }
 
-       if (uSN > replmd_private->ncs[i].mod_usn) {
-           replmd_private->ncs[i].mod_usn = uSN;
+       partition = talloc_get_type_abort(partition_ctrl->data,
+                                   struct dsdb_control_current_partition);
+       
+       if (ac->seq_num > 0) {
+               for (modified_partition = replmd_private->ncs; modified_partition; 
+                    modified_partition = modified_partition->next) {
+                       if (ldb_dn_compare(modified_partition->dn, partition->dn) == 0) {
+                               break;
+                       }
+               }
+               
+               if (modified_partition == NULL) {
+                       modified_partition = talloc_zero(replmd_private, struct nc_entry);
+                       if (!modified_partition) {
+                               ldb_oom(ldb_module_get_ctx(ac->module));
+                               return ldb_module_done(ac->req, NULL,
+                                                      NULL, LDB_ERR_OPERATIONS_ERROR);
+                       }
+                       modified_partition->dn = ldb_dn_copy(modified_partition, partition->dn);
+                       if (!modified_partition->dn) {
+                               ldb_oom(ldb_module_get_ctx(ac->module));
+                               return ldb_module_done(ac->req, NULL,
+                                                      NULL, LDB_ERR_OPERATIONS_ERROR);
+                       }
+                       DLIST_ADD(replmd_private->ncs, modified_partition);
+               }
+
+               if (ac->seq_num > modified_partition->mod_usn) {
+                       modified_partition->mod_usn = ac->seq_num;
+                       if (ac->is_urgent) {
+                               modified_partition->mod_usn_urgent = ac->seq_num;
+                       }
+               }
        }
 
-       return LDB_SUCCESS;
+       if (ac->apply_mode) {
+               talloc_free(ares);
+               ac->index_current++;
+               
+               ret = replmd_replicated_apply_next(ac);
+               if (ret != LDB_SUCCESS) {
+                       return ldb_module_done(ac->req, NULL, NULL, ret);
+               }
+               return ret;
+       } else {
+               /* free the partition control container here, for the
+                * common path.  Other cases will have it cleaned up
+                * eventually with the ares */
+               talloc_free(partition_ctrl);
+               return ldb_module_done(ac->req, 
+                                      controls_except_specified(controls, ares, partition_ctrl),
+                                      ares->response, LDB_SUCCESS);
+       }
 }
 
 
@@ -233,27 +444,24 @@ static int replmd_notify(struct ldb_module *module, struct ldb_dn *dn, uint64_t
  */
 static int replmd_notify_store(struct ldb_module *module)
 {
-       int i;
-       struct replmd_private *replmd_private = 
+       struct replmd_private *replmd_private =
                talloc_get_type(ldb_module_get_private(module), struct replmd_private);
        struct ldb_context *ldb = ldb_module_get_ctx(module);
 
-       for (i=0; i<replmd_private->num_ncs; i++) {
+       while (replmd_private->ncs) {
                int ret;
+               struct nc_entry *modified_partition = replmd_private->ncs;
 
-               if (replmd_private->ncs[i].mod_usn == 0) {
-                       /* this partition has not changed in this
-                          transaction */
-                       continue;
-               }
-
-               ret = dsdb_save_partition_usn(ldb, replmd_private->ncs[i].dn, 
-                                             replmd_private->ncs[i].mod_usn);
+               ret = dsdb_save_partition_usn(ldb, modified_partition->dn,
+                                               modified_partition->mod_usn,
+                                               modified_partition->mod_usn_urgent);
                if (ret != LDB_SUCCESS) {
                        DEBUG(0,(__location__ ": Failed to save partition uSN for %s\n",
-                                ldb_dn_get_linearized(replmd_private->ncs[i].dn)));
+                                ldb_dn_get_linearized(modified_partition->dn)));
                        return ret;
                }
+               DLIST_REMOVE(replmd_private->ncs, modified_partition);
+               talloc_free(modified_partition);
        }
 
        return LDB_SUCCESS;
@@ -279,6 +487,15 @@ static struct replmd_replicated_request *replmd_ctx_init(struct ldb_module *modu
 
        ac->module = module;
        ac->req = req;
+
+       ac->schema = dsdb_get_schema(ldb);
+       if (!ac->schema) {
+               ldb_debug_set(ldb, LDB_DEBUG_FATAL,
+                             "replmd_modify: no dsdb_schema loaded");
+               DEBUG(0,(__location__ ": %s\n", ldb_errstring(ldb)));
+               return NULL;
+       }
+
        return ac;
 }
 
@@ -360,7 +577,7 @@ static int replmd_replPropertyMetaData1_attid_sort(const struct replPropertyMeta
                return -1;
        }
 
-       return m1->attid - m2->attid;
+       return m1->attid > m2->attid ? 1 : -1;
 }
 
 static int replmd_replPropertyMetaDataCtr1_sort(struct replPropertyMetaDataCtr1 *ctr1,
@@ -414,8 +631,10 @@ static int replmd_ldb_message_element_attid_sort(const struct ldb_message_elemen
        if (!a1 || !a2) {
                return strcasecmp(e1->name, e2->name);
        }
-
-       return a1->attributeID_id - a2->attributeID_id;
+       if (a1->attributeID_id == a2->attributeID_id) {
+               return 0;
+       }
+       return a1->attributeID_id > a2->attributeID_id ? 1 : -1;
 }
 
 static void replmd_ldb_message_sort(struct ldb_message *msg,
@@ -425,54 +644,101 @@ static void replmd_ldb_message_sort(struct ldb_message *msg,
                  discard_const_p(void, schema), (ldb_qsort_cmp_fn_t)replmd_ldb_message_element_attid_sort);
 }
 
-static int replmd_op_callback(struct ldb_request *req, struct ldb_reply *ares)
+static int replmd_build_la_val(TALLOC_CTX *mem_ctx, struct ldb_val *v, struct dsdb_dn *dsdb_dn,
+                              const struct GUID *invocation_id, uint64_t seq_num,
+                              uint64_t local_usn, NTTIME nttime, uint32_t version, bool deleted);
+
+
+/*
+  fix up linked attributes in replmd_add.
+  This involves setting up the right meta-data in extended DN
+  components, and creating backlinks to the object
+ */
+static int replmd_add_fix_la(struct ldb_module *module, struct ldb_message_element *el,
+                            uint64_t seq_num, const struct GUID *invocationId, time_t t,
+                            struct GUID *guid, const struct dsdb_attribute *sa)
 {
-       struct ldb_context *ldb;
-       struct replmd_replicated_request *ac;
+       int i;
+       TALLOC_CTX *tmp_ctx = talloc_new(el->values);
+       struct ldb_context *ldb = ldb_module_get_ctx(module);
+       struct dsdb_schema *schema = dsdb_get_schema(ldb);
+       NTTIME now;
 
-       ac = talloc_get_type(req->context, struct replmd_replicated_request);
-       ldb = ldb_module_get_ctx(ac->module);
+       unix_to_nt_time(&now, t);
 
-       if (!ares) {
-               return ldb_module_done(ac->req, NULL, NULL,
-                                       LDB_ERR_OPERATIONS_ERROR);
-       }
-       if (ares->error != LDB_SUCCESS) {
-               return ldb_module_done(ac->req, ares->controls,
-                                       ares->response, ares->error);
-       }
+       for (i=0; i<el->num_values; i++) {
+               struct ldb_val *v = &el->values[i];
+               struct dsdb_dn *dsdb_dn = dsdb_dn_parse(tmp_ctx, ldb, v, sa->syntax->ldap_oid);
+               struct GUID target_guid;
+               NTSTATUS status;
+               int ret;
 
-       if (ares->type != LDB_REPLY_DONE) {
-               ldb_set_errstring(ldb,
-                                 "invalid ldb_reply_type in callback");
-               talloc_free(ares);
-               return ldb_module_done(ac->req, NULL, NULL,
-                                       LDB_ERR_OPERATIONS_ERROR);
+               /* note that the DN already has the extended
+                  components from the extended_dn_store module */
+               status = dsdb_get_extended_dn_guid(dsdb_dn->dn, &target_guid, "GUID");
+               if (!NT_STATUS_IS_OK(status) || GUID_all_zero(&target_guid)) {
+                       ret = dsdb_module_guid_by_dn(module, dsdb_dn->dn, &target_guid);
+                       if (ret != LDB_SUCCESS) {
+                               talloc_free(tmp_ctx);
+                               return ret;
+                       }
+                       ret = dsdb_set_extended_dn_guid(dsdb_dn->dn, &target_guid, "GUID");
+                       if (ret != LDB_SUCCESS) {
+                               talloc_free(tmp_ctx);
+                               return ret;
+                       }
+               }
+
+               ret = replmd_build_la_val(el->values, v, dsdb_dn, invocationId,
+                                         seq_num, seq_num, now, 0, false);
+               if (ret != LDB_SUCCESS) {
+                       talloc_free(tmp_ctx);
+                       return ret;
+               }
+
+               ret = replmd_add_backlink(module, schema, guid, &target_guid, true, sa, false);
+               if (ret != LDB_SUCCESS) {
+                       talloc_free(tmp_ctx);
+                       return ret;
+               }
        }
 
-       return ldb_module_done(ac->req, ares->controls,
-                               ares->response, LDB_SUCCESS);
+       talloc_free(tmp_ctx);
+       return LDB_SUCCESS;
 }
 
+
+/*
+  intercept add requests
+ */
 static int replmd_add(struct ldb_module *module, struct ldb_request *req)
 {
        struct ldb_context *ldb;
+        struct ldb_control *control;
        struct replmd_replicated_request *ac;
-       const struct dsdb_schema *schema;
        enum ndr_err_code ndr_err;
        struct ldb_request *down_req;
        struct ldb_message *msg;
+        const DATA_BLOB *guid_blob;
        struct GUID guid;
-       struct ldb_val guid_value;
        struct replPropertyMetaDataBlob nmd;
        struct ldb_val nmd_value;
-       uint64_t seq_num;
        const struct GUID *our_invocation_id;
        time_t t = time(NULL);
        NTTIME now;
        char *time_str;
        int ret;
        uint32_t i, ni=0;
+       bool allow_add_guid = false;
+       bool remove_current_guid = false;
+       bool is_urgent = false;
+       struct ldb_message_element *objectclass_el;
+
+        /* check if there's a show relax control (used by provision to say 'I know what I'm doing') */
+        control = ldb_request_get_control(req, LDB_CONTROL_RELAX_OID);
+       if (control) {
+               allow_add_guid = true;
+       }
 
        /* do not manipulate our control entries */
        if (ldb_dn_is_special(req->op.add.message->dn)) {
@@ -483,41 +749,48 @@ static int replmd_add(struct ldb_module *module, struct ldb_request *req)
 
        ldb_debug(ldb, LDB_DEBUG_TRACE, "replmd_add\n");
 
-       schema = dsdb_get_schema(ldb);
-       if (!schema) {
-               ldb_debug_set(ldb, LDB_DEBUG_FATAL,
-                             "replmd_add: no dsdb_schema loaded");
-               DEBUG(0,(__location__ ": %s\n", ldb_errstring(ldb)));
-               return LDB_ERR_CONSTRAINT_VIOLATION;
-       }
-
        ac = replmd_ctx_init(module, req);
        if (!ac) {
                return LDB_ERR_OPERATIONS_ERROR;
        }
 
-       ac->schema = schema;
-
-       if (ldb_msg_find_element(req->op.add.message, "objectGUID") != NULL) {
-               ldb_debug_set(ldb, LDB_DEBUG_ERROR,
+        guid_blob = ldb_msg_find_ldb_val(req->op.add.message, "objectGUID");
+       if ( guid_blob != NULL ) {
+               if( !allow_add_guid ) {
+                       ldb_debug_set(ldb, LDB_DEBUG_ERROR,
                              "replmd_add: it's not allowed to add an object with objectGUID\n");
-               return LDB_ERR_UNWILLING_TO_PERFORM;
+                       talloc_free(ac);
+                       return LDB_ERR_UNWILLING_TO_PERFORM;
+               } else {
+                       NTSTATUS status = GUID_from_data_blob(guid_blob,&guid);
+                       if ( !NT_STATUS_IS_OK(status)) {
+                                       ldb_debug_set(ldb, LDB_DEBUG_ERROR,
+                                     "replmd_add: Unable to parse as a GUID the attribute objectGUID\n");
+                               talloc_free(ac);
+                               return LDB_ERR_UNWILLING_TO_PERFORM;
+                       }
+                       /* we remove this attribute as it can be a string and will not be treated 
+                       correctly and then we will readd it latter on in the good format*/
+                       remove_current_guid = true;
+               }
+       } else {
+               /* a new GUID */
+               guid = GUID_random();
        }
 
        /* Get a sequence number from the backend */
-       ret = ldb_sequence_number(ldb, LDB_SEQ_NEXT, &seq_num);
+       ret = ldb_sequence_number(ldb, LDB_SEQ_NEXT, &ac->seq_num);
        if (ret != LDB_SUCCESS) {
+               talloc_free(ac);
                return ret;
        }
 
-       /* a new GUID */
-       guid = GUID_random();
-
        /* get our invocationId */
        our_invocation_id = samdb_ntds_invocation_id(ldb);
        if (!our_invocation_id) {
                ldb_debug_set(ldb, LDB_DEBUG_ERROR,
                              "replmd_add: unable to find invocationId\n");
+               talloc_free(ac);
                return LDB_ERR_OPERATIONS_ERROR;
        }
 
@@ -525,6 +798,7 @@ static int replmd_add(struct ldb_module *module, struct ldb_request *req)
        msg = ldb_msg_copy_shallow(ac, req->op.add.message);
        if (msg == NULL) {
                ldb_oom(ldb);
+               talloc_free(ac);
                return LDB_ERR_OPERATIONS_ERROR;
        }
 
@@ -532,8 +806,13 @@ static int replmd_add(struct ldb_module *module, struct ldb_request *req)
        unix_to_nt_time(&now, t);
        time_str = ldb_timestring(msg, t);
        if (!time_str) {
+               ldb_oom(ldb);
+               talloc_free(ac);
                return LDB_ERR_OPERATIONS_ERROR;
        }
+       if (remove_current_guid) {
+               ldb_msg_remove_attr(msg,"objectGUID");
+       }
 
        /* 
         * remove autogenerated attributes
@@ -544,21 +823,14 @@ static int replmd_add(struct ldb_module *module, struct ldb_request *req)
        ldb_msg_remove_attr(msg, "uSNChanged");
        ldb_msg_remove_attr(msg, "replPropertyMetaData");
 
-       if (!ldb_msg_find_element(req->op.add.message, "instanceType")) {
-               ret = ldb_msg_add_fmt(msg, "instanceType", "%u", INSTANCE_TYPE_WRITE);
-               if (ret != LDB_SUCCESS) {
-                       ldb_oom(ldb);
-                       return LDB_ERR_OPERATIONS_ERROR;
-               }
-       }
-
        /*
         * readd replicated attributes
         */
        ret = ldb_msg_add_string(msg, "whenCreated", time_str);
        if (ret != LDB_SUCCESS) {
                ldb_oom(ldb);
-               return LDB_ERR_OPERATIONS_ERROR;
+               talloc_free(ac);
+               return ret;
        }
 
        /* build the replication meta_data */
@@ -570,6 +842,7 @@ static int replmd_add(struct ldb_module *module, struct ldb_request *req)
                                               nmd.ctr.ctr1.count);
        if (!nmd.ctr.ctr1.array) {
                ldb_oom(ldb);
+               talloc_free(ac);
                return LDB_ERR_OPERATIONS_ERROR;
        }
 
@@ -580,11 +853,12 @@ static int replmd_add(struct ldb_module *module, struct ldb_request *req)
 
                if (e->name[0] == '@') continue;
 
-               sa = dsdb_attribute_by_lDAPDisplayName(schema, e->name);
+               sa = dsdb_attribute_by_lDAPDisplayName(ac->schema, e->name);
                if (!sa) {
                        ldb_debug_set(ldb, LDB_DEBUG_ERROR,
                                      "replmd_add: attribute '%s' not defined in schema\n",
                                      e->name);
+                       talloc_free(ac);
                        return LDB_ERR_NO_SUCH_ATTRIBUTE;
                }
 
@@ -595,12 +869,25 @@ static int replmd_add(struct ldb_module *module, struct ldb_request *req)
                        continue;
                }
 
+#if W2K3_LINKED_ATTRIBUTES
+               if (sa->linkID != 0 && dsdb_functional_level(ldb) > DS_DOMAIN_FUNCTION_2000) {
+                       ret = replmd_add_fix_la(module, e, ac->seq_num, our_invocation_id, t, &guid, sa);
+                       if (ret != LDB_SUCCESS) {
+                               talloc_free(ac);
+                               return ret;
+                       }
+                       /* linked attributes are not stored in
+                          replPropertyMetaData in FL above w2k */
+                       continue;
+               }
+#endif
+
                m->attid                        = sa->attributeID_id;
                m->version                      = 1;
                m->originating_change_time      = now;
                m->originating_invocation_id    = *our_invocation_id;
-               m->originating_usn              = seq_num;
-               m->local_usn                    = seq_num;
+               m->originating_usn              = ac->seq_num;
+               m->local_usn                    = ac->seq_num;
                ni++;
        }
 
@@ -610,75 +897,81 @@ static int replmd_add(struct ldb_module *module, struct ldb_request *req)
        /*
         * sort meta data array, and move the rdn attribute entry to the end
         */
-       ret = replmd_replPropertyMetaDataCtr1_sort(&nmd.ctr.ctr1, schema, msg->dn);
+       ret = replmd_replPropertyMetaDataCtr1_sort(&nmd.ctr.ctr1, ac->schema, msg->dn);
        if (ret != LDB_SUCCESS) {
+               talloc_free(ac);
                return ret;
        }
 
        /* generated NDR encoded values */
-       ndr_err = ndr_push_struct_blob(&guid_value, msg, 
-                                      NULL,
-                                      &guid,
-                                      (ndr_push_flags_fn_t)ndr_push_GUID);
-       if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
-               ldb_oom(ldb);
-               return LDB_ERR_OPERATIONS_ERROR;
-       }
        ndr_err = ndr_push_struct_blob(&nmd_value, msg, 
                                       lp_iconv_convenience(ldb_get_opaque(ldb, "loadparm")),
                                       &nmd,
                                       (ndr_push_flags_fn_t)ndr_push_replPropertyMetaDataBlob);
        if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
                ldb_oom(ldb);
+               talloc_free(ac);
                return LDB_ERR_OPERATIONS_ERROR;
        }
 
        /*
         * add the autogenerated values
         */
-       ret = ldb_msg_add_value(msg, "objectGUID", &guid_value, NULL);
+       ret = dsdb_msg_add_guid(msg, &guid, "objectGUID");
        if (ret != LDB_SUCCESS) {
                ldb_oom(ldb);
-               return LDB_ERR_OPERATIONS_ERROR;
+               talloc_free(ac);
+               return ret;
        }
        ret = ldb_msg_add_string(msg, "whenChanged", time_str);
        if (ret != LDB_SUCCESS) {
                ldb_oom(ldb);
-               return LDB_ERR_OPERATIONS_ERROR;
+               talloc_free(ac);
+               return ret;
        }
-       ret = samdb_msg_add_uint64(ldb, msg, msg, "uSNCreated", seq_num);
+       ret = samdb_msg_add_uint64(ldb, msg, msg, "uSNCreated", ac->seq_num);
        if (ret != LDB_SUCCESS) {
                ldb_oom(ldb);
-               return LDB_ERR_OPERATIONS_ERROR;
+               talloc_free(ac);
+               return ret;
        }
-       ret = samdb_msg_add_uint64(ldb, msg, msg, "uSNChanged", seq_num);
+       ret = samdb_msg_add_uint64(ldb, msg, msg, "uSNChanged", ac->seq_num);
        if (ret != LDB_SUCCESS) {
                ldb_oom(ldb);
-               return LDB_ERR_OPERATIONS_ERROR;
+               talloc_free(ac);
+               return ret;
        }
        ret = ldb_msg_add_value(msg, "replPropertyMetaData", &nmd_value, NULL);
        if (ret != LDB_SUCCESS) {
                ldb_oom(ldb);
-               return LDB_ERR_OPERATIONS_ERROR;
+               talloc_free(ac);
+               return ret;
        }
 
        /*
         * sort the attributes by attid before storing the object
         */
-       replmd_ldb_message_sort(msg, schema);
+       replmd_ldb_message_sort(msg, ac->schema);
 
+       objectclass_el = ldb_msg_find_element(msg, "objectClass");
+       is_urgent = replmd_check_urgent_objectclass(objectclass_el,
+                                                       REPL_URGENT_ON_CREATE);
+
+       ac->is_urgent = is_urgent;
        ret = ldb_build_add_req(&down_req, ldb, ac,
                                msg,
                                req->controls,
                                ac, replmd_op_callback,
                                req);
+
        if (ret != LDB_SUCCESS) {
+               talloc_free(ac);
                return ret;
        }
 
-       ret = replmd_notify(module, msg->dn, seq_num);
-       if (ret != LDB_SUCCESS) {
-               return ret;
+       /* mark the control done */
+       if (control) {
+               control->critical = 0;
        }
 
        /* go on with the call chain */
@@ -689,11 +982,11 @@ static int replmd_add(struct ldb_module *module, struct ldb_request *req)
 /*
  * update the replPropertyMetaData for one element
  */
-static int replmd_update_rpmd_element(struct ldb_context *ldb, 
+static int replmd_update_rpmd_element(struct ldb_context *ldb,
                                      struct ldb_message *msg,
                                      struct ldb_message_element *el,
                                      struct replPropertyMetaDataBlob *omd,
-                                     struct dsdb_schema *schema,
+                                     const struct dsdb_schema *schema,
                                      uint64_t *seq_num,
                                      const struct GUID *our_invocation_id,
                                      NTTIME now)
@@ -716,6 +1009,20 @@ static int replmd_update_rpmd_element(struct ldb_context *ldb,
        for (i=0; i<omd->ctr.ctr1.count; i++) {
                if (a->attributeID_id == omd->ctr.ctr1.array[i].attid) break;
        }
+
+#if W2K3_LINKED_ATTRIBUTES
+       if (a->linkID != 0 && dsdb_functional_level(ldb) > DS_DOMAIN_FUNCTION_2000) {
+               /* linked attributes are not stored in
+                  replPropertyMetaData in FL above w2k, but we do
+                  raise the seqnum for the object  */
+               if (*seq_num == 0 &&
+                   ldb_sequence_number(ldb, LDB_SEQ_NEXT, seq_num) != LDB_SUCCESS) {
+                       return LDB_ERR_OPERATIONS_ERROR;
+               }
+               return LDB_SUCCESS;
+       }
+#endif
+
        if (i == omd->ctr.ctr1.count) {
                /* we need to add a new one */
                omd->ctr.ctr1.array = talloc_realloc(msg, omd->ctr.ctr1.array, 
@@ -756,20 +1063,22 @@ static int replmd_update_rpmd_element(struct ldb_context *ldb,
  * client is based on this object 
  */
 static int replmd_update_rpmd(struct ldb_module *module, 
-                             struct ldb_message *msg, uint64_t *seq_num)
+                             const struct dsdb_schema *schema, 
+                             struct ldb_message *msg, uint64_t *seq_num,
+                             time_t t,
+                             bool *is_urgent)
 {
        const struct ldb_val *omd_value;
        enum ndr_err_code ndr_err;
        struct replPropertyMetaDataBlob omd;
        int i;
-       struct dsdb_schema *schema;
-       time_t t = time(NULL);
        NTTIME now;
        const struct GUID *our_invocation_id;
        int ret;
-       const char *attrs[] = { "replPropertyMetaData" , NULL };
+       const char *attrs[] = { "replPropertyMetaData" , "objectClass", NULL };
        struct ldb_result *res;
        struct ldb_context *ldb;
+       struct ldb_message_element *objectclass_el;
 
        ldb = ldb_module_get_ctx(module);
 
@@ -785,12 +1094,17 @@ static int replmd_update_rpmd(struct ldb_module *module,
 
        /* search for the existing replPropertyMetaDataBlob */
        ret = dsdb_search_dn_with_deleted(ldb, msg, &res, msg->dn, attrs);
-       if (ret != LDB_SUCCESS || res->count < 1) {
+       if (ret != LDB_SUCCESS || res->count != 1) {
                DEBUG(0,(__location__ ": Object %s failed to find replPropertyMetaData\n",
                         ldb_dn_get_linearized(msg->dn)));
                return LDB_ERR_OPERATIONS_ERROR;
        }
-               
+
+       objectclass_el = ldb_msg_find_element(res->msgs[0], "objectClass");
+       if (is_urgent && replmd_check_urgent_objectclass(objectclass_el,
+                                                       REPL_URGENT_ON_UPDATE)) {
+               *is_urgent = true;
+       }
 
        omd_value = ldb_msg_find_ldb_val(res->msgs[0], "replPropertyMetaData");
        if (!omd_value) {
@@ -814,14 +1128,17 @@ static int replmd_update_rpmd(struct ldb_module *module,
                return LDB_ERR_OPERATIONS_ERROR;
        }
 
-       schema = dsdb_get_schema(ldb);
-
        for (i=0; i<msg->num_elements; i++) {
-               ret = replmd_update_rpmd_element(ldb, msg, &msg->elements[i], &omd, schema, seq_num, 
+               ret = replmd_update_rpmd_element(ldb, msg, &msg->elements[i], &omd, schema, seq_num,
                                                 our_invocation_id, now);
                if (ret != LDB_SUCCESS) {
                        return ret;
                }
+
+               if (is_urgent && !*is_urgent) {
+                       *is_urgent = replmd_check_urgent_attribute(&msg->elements[i]);
+               }
+
        }
 
        /*
@@ -860,11 +1177,6 @@ static int replmd_update_rpmd(struct ldb_module *module,
                        return ret;
                }
 
-               ret = replmd_notify(module, msg->dn, *seq_num);
-               if (ret != LDB_SUCCESS) {
-                       return ret;
-               }
-
                el->num_values = 1;
                el->values = md_value;
        }
@@ -872,193 +1184,1336 @@ static int replmd_update_rpmd(struct ldb_module *module,
        return LDB_SUCCESS;     
 }
 
+struct parsed_dn {
+       struct dsdb_dn *dsdb_dn;
+       struct GUID *guid;
+       struct ldb_val *v;
+};
 
-static int replmd_modify(struct ldb_module *module, struct ldb_request *req)
+static int parsed_dn_compare(struct parsed_dn *pdn1, struct parsed_dn *pdn2)
 {
-       struct ldb_context *ldb;
-       struct replmd_replicated_request *ac;
-       const struct dsdb_schema *schema;
-       struct ldb_request *down_req;
-       struct ldb_message *msg;
+       return GUID_compare(pdn1->guid, pdn2->guid);
+}
+
+static struct parsed_dn *parsed_dn_find(struct parsed_dn *pdn, int count, struct GUID *guid, struct ldb_dn *dn)
+{
+       struct parsed_dn *ret;
+       if (dn && GUID_all_zero(guid)) {
+               /* when updating a link using DRS, we sometimes get a
+                  NULL GUID. We then need to try and match by DN */
+               int i;
+               for (i=0; i<count; i++) {
+                       if (ldb_dn_compare(pdn[i].dsdb_dn->dn, dn) == 0) {
+                               dsdb_get_extended_dn_guid(pdn[i].dsdb_dn->dn, guid, "GUID");
+                               return &pdn[i];
+                       }
+               }
+               return NULL;
+       }
+       BINARY_ARRAY_SEARCH(pdn, count, guid, guid, GUID_compare, ret);
+       return ret;
+}
+
+/*
+  get a series of message element values as an array of DNs and GUIDs
+  the result is sorted by GUID
+ */
+static int get_parsed_dns(struct ldb_module *module, TALLOC_CTX *mem_ctx,
+                         struct ldb_message_element *el, struct parsed_dn **pdn,
+                         const char *ldap_oid)
+{
+       int i;
+       struct ldb_context *ldb = ldb_module_get_ctx(module);
+
+       if (el == NULL) {
+               *pdn = NULL;
+               return LDB_SUCCESS;
+       }
+
+       (*pdn) = talloc_array(mem_ctx, struct parsed_dn, el->num_values);
+       if (!*pdn) {
+               ldb_module_oom(module);
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       for (i=0; i<el->num_values; i++) {
+               struct ldb_val *v = &el->values[i];
+               NTSTATUS status;
+               struct ldb_dn *dn;
+               struct parsed_dn *p;
+
+               p = &(*pdn)[i];
+
+               p->dsdb_dn = dsdb_dn_parse(*pdn, ldb, v, ldap_oid);
+               if (p->dsdb_dn == NULL) {
+                       return LDB_ERR_INVALID_DN_SYNTAX;
+               }
+
+               dn = p->dsdb_dn->dn;
+
+               p->guid = talloc(*pdn, struct GUID);
+               if (p->guid == NULL) {
+                       ldb_module_oom(module);
+                       return LDB_ERR_OPERATIONS_ERROR;
+               }
+
+               status = dsdb_get_extended_dn_guid(dn, p->guid, "GUID");
+               if (NT_STATUS_EQUAL(status, NT_STATUS_OBJECT_NAME_NOT_FOUND)) {
+                       /* we got a DN without a GUID - go find the GUID */
+                       int ret = dsdb_module_guid_by_dn(module, dn, p->guid);
+                       if (ret != LDB_SUCCESS) {
+                               ldb_asprintf_errstring(ldb, "Unable to find GUID for DN %s\n",
+                                                      ldb_dn_get_linearized(dn));
+                               return ret;
+                       }
+                       ret = dsdb_set_extended_dn_guid(dn, p->guid, "GUID");
+                       if (ret != LDB_SUCCESS) {
+                               return ret;
+                       }
+               } else if (!NT_STATUS_IS_OK(status)) {
+                       return LDB_ERR_OPERATIONS_ERROR;
+               }
+
+               /* keep a pointer to the original ldb_val */
+               p->v = v;
+       }
+
+       qsort(*pdn, el->num_values, sizeof((*pdn)[0]), (comparison_fn_t)parsed_dn_compare);
+
+       return LDB_SUCCESS;
+}
+
+/*
+  build a new extended DN, including all meta data fields
+
+  RMD_FLAGS           = DSDB_RMD_FLAG_* bits
+  RMD_ADDTIME         = originating_add_time
+  RMD_INVOCID         = originating_invocation_id
+  RMD_CHANGETIME      = originating_change_time
+  RMD_ORIGINATING_USN = originating_usn
+  RMD_LOCAL_USN       = local_usn
+  RMD_VERSION         = version
+ */
+static int replmd_build_la_val(TALLOC_CTX *mem_ctx, struct ldb_val *v, struct dsdb_dn *dsdb_dn,
+                              const struct GUID *invocation_id, uint64_t seq_num,
+                              uint64_t local_usn, NTTIME nttime, uint32_t version, bool deleted)
+{
+       struct ldb_dn *dn = dsdb_dn->dn;
+       const char *tstring, *usn_string, *flags_string;
+       struct ldb_val tval;
+       struct ldb_val iid;
+       struct ldb_val usnv, local_usnv;
+       struct ldb_val vers, flagsv;
+       NTSTATUS status;
        int ret;
-       time_t t = time(NULL);
-       uint64_t seq_num = 0;
+       const char *dnstring;
+       char *vstring;
+       uint32_t rmd_flags = deleted?DSDB_RMD_FLAG_DELETED:0;
 
-       /* do not manipulate our control entries */
-       if (ldb_dn_is_special(req->op.mod.message->dn)) {
-               return ldb_next_request(module, req);
+       tstring = talloc_asprintf(mem_ctx, "%llu", (unsigned long long)nttime);
+       if (!tstring) {
+               return LDB_ERR_OPERATIONS_ERROR;
        }
+       tval = data_blob_string_const(tstring);
 
-       ldb = ldb_module_get_ctx(module);
+       usn_string = talloc_asprintf(mem_ctx, "%llu", (unsigned long long)seq_num);
+       if (!usn_string) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+       usnv = data_blob_string_const(usn_string);
 
-       ldb_debug(ldb, LDB_DEBUG_TRACE, "replmd_modify\n");
+       usn_string = talloc_asprintf(mem_ctx, "%llu", (unsigned long long)local_usn);
+       if (!usn_string) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+       local_usnv = data_blob_string_const(usn_string);
 
-       schema = dsdb_get_schema(ldb);
-       if (!schema) {
-               ldb_debug_set(ldb, LDB_DEBUG_FATAL,
-                             "replmd_modify: no dsdb_schema loaded");
-               DEBUG(0,(__location__ ": %s\n", ldb_errstring(ldb)));
-               return LDB_ERR_CONSTRAINT_VIOLATION;
+       vstring = talloc_asprintf(mem_ctx, "%lu", (unsigned long)version);
+       if (!vstring) {
+               return LDB_ERR_OPERATIONS_ERROR;
        }
+       vers = data_blob_string_const(vstring);
 
-       ac = replmd_ctx_init(module, req);
-       if (!ac) {
+       status = GUID_to_ndr_blob(invocation_id, dn, &iid);
+       if (!NT_STATUS_IS_OK(status)) {
                return LDB_ERR_OPERATIONS_ERROR;
        }
 
-       ac->schema = schema;
+       flags_string = talloc_asprintf(mem_ctx, "%u", rmd_flags);
+       if (!flags_string) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+       flagsv = data_blob_string_const(flags_string);
+
+       ret = ldb_dn_set_extended_component(dn, "RMD_FLAGS", &flagsv);
+       if (ret != LDB_SUCCESS) return ret;
+       ret = ldb_dn_set_extended_component(dn, "RMD_ADDTIME", &tval);
+       if (ret != LDB_SUCCESS) return ret;
+       ret = ldb_dn_set_extended_component(dn, "RMD_INVOCID", &iid);
+       if (ret != LDB_SUCCESS) return ret;
+       ret = ldb_dn_set_extended_component(dn, "RMD_CHANGETIME", &tval);
+       if (ret != LDB_SUCCESS) return ret;
+       ret = ldb_dn_set_extended_component(dn, "RMD_LOCAL_USN", &local_usnv);
+       if (ret != LDB_SUCCESS) return ret;
+       ret = ldb_dn_set_extended_component(dn, "RMD_ORIGINATING_USN", &usnv);
+       if (ret != LDB_SUCCESS) return ret;
+       ret = ldb_dn_set_extended_component(dn, "RMD_VERSION", &vers);
+       if (ret != LDB_SUCCESS) return ret;
+
+       dnstring = dsdb_dn_get_extended_linearized(mem_ctx, dsdb_dn, 1);
+       if (dnstring == NULL) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+       *v = data_blob_string_const(dnstring);
 
-       /* we have to copy the message as the caller might have it as a const */
-       msg = ldb_msg_copy_shallow(ac, req->op.mod.message);
-       if (msg == NULL) {
-               talloc_free(ac);
+       return LDB_SUCCESS;
+}
+
+static int replmd_update_la_val(TALLOC_CTX *mem_ctx, struct ldb_val *v, struct dsdb_dn *dsdb_dn,
+                               struct dsdb_dn *old_dsdb_dn, const struct GUID *invocation_id,
+                               uint64_t seq_num, uint64_t local_usn, NTTIME nttime,
+                               uint32_t version, bool deleted);
+
+/*
+  check if any links need upgrading from w2k format
+ */
+static int replmd_check_upgrade_links(struct parsed_dn *dns, uint32_t count, const struct GUID *invocation_id)
+{
+       int i;
+       for (i=0; i<count; i++) {
+               NTSTATUS status;
+               uint32_t version;
+               int ret;
+
+               status = dsdb_get_extended_dn_uint32(dns[i].dsdb_dn->dn, &version, "RMD_VERSION");
+               if (!NT_STATUS_EQUAL(status, NT_STATUS_OBJECT_NAME_NOT_FOUND)) {
+                       continue;
+               }
+
+               /* it's an old one that needs upgrading */
+               ret = replmd_update_la_val(dns, dns[i].v, dns[i].dsdb_dn, dns[i].dsdb_dn, invocation_id,
+                                          1, 1, 0, 0, false);
+               if (ret != LDB_SUCCESS) {
+                       return ret;
+               }
+       }
+       return LDB_SUCCESS;
+}
+
+/*
+  update an extended DN, including all meta data fields
+
+  see replmd_build_la_val for value names
+ */
+static int replmd_update_la_val(TALLOC_CTX *mem_ctx, struct ldb_val *v, struct dsdb_dn *dsdb_dn,
+                               struct dsdb_dn *old_dsdb_dn, const struct GUID *invocation_id,
+                               uint64_t seq_num, uint64_t local_usn, NTTIME nttime,
+                               uint32_t version, bool deleted)
+{
+       struct ldb_dn *dn = dsdb_dn->dn;
+       const char *tstring, *usn_string, *flags_string;
+       struct ldb_val tval;
+       struct ldb_val iid;
+       struct ldb_val usnv, local_usnv;
+       struct ldb_val vers, flagsv;
+       const struct ldb_val *old_addtime;
+       uint32_t old_version;
+       NTSTATUS status;
+       int ret;
+       const char *dnstring;
+       char *vstring;
+       uint32_t rmd_flags = deleted?DSDB_RMD_FLAG_DELETED:0;
+
+       tstring = talloc_asprintf(mem_ctx, "%llu", (unsigned long long)nttime);
+       if (!tstring) {
                return LDB_ERR_OPERATIONS_ERROR;
        }
+       tval = data_blob_string_const(tstring);
 
-       /* TODO:
-        * - get the whole old object
-        * - if the old object doesn't exist report an error
-        * - give an error when a readonly attribute should
-        *   be modified
-        * - merge the changed into the old object
-        *   if the caller set values to the same value
-        *   ignore the attribute, return success when no
-        *   attribute was changed
-        */
+       usn_string = talloc_asprintf(mem_ctx, "%llu", (unsigned long long)seq_num);
+       if (!usn_string) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+       usnv = data_blob_string_const(usn_string);
+
+       usn_string = talloc_asprintf(mem_ctx, "%llu", (unsigned long long)local_usn);
+       if (!usn_string) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+       local_usnv = data_blob_string_const(usn_string);
+
+       status = GUID_to_ndr_blob(invocation_id, dn, &iid);
+       if (!NT_STATUS_IS_OK(status)) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       flags_string = talloc_asprintf(mem_ctx, "%u", rmd_flags);
+       if (!flags_string) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+       flagsv = data_blob_string_const(flags_string);
+
+       ret = ldb_dn_set_extended_component(dn, "RMD_FLAGS", &flagsv);
+       if (ret != LDB_SUCCESS) return ret;
+
+       /* get the ADDTIME from the original */
+       old_addtime = ldb_dn_get_extended_component(old_dsdb_dn->dn, "RMD_ADDTIME");
+       if (old_addtime == NULL) {
+               old_addtime = &tval;
+       }
+       if (dsdb_dn != old_dsdb_dn) {
+               ret = ldb_dn_set_extended_component(dn, "RMD_ADDTIME", old_addtime);
+               if (ret != LDB_SUCCESS) return ret;
+       }
+
+       /* use our invocation id */
+       ret = ldb_dn_set_extended_component(dn, "RMD_INVOCID", &iid);
+       if (ret != LDB_SUCCESS) return ret;
+
+       /* changetime is the current time */
+       ret = ldb_dn_set_extended_component(dn, "RMD_CHANGETIME", &tval);
+       if (ret != LDB_SUCCESS) return ret;
 
-       ret = replmd_update_rpmd(module, msg, &seq_num);
+       /* update the USN */
+       ret = ldb_dn_set_extended_component(dn, "RMD_ORIGINATING_USN", &usnv);
+       if (ret != LDB_SUCCESS) return ret;
+
+       ret = ldb_dn_set_extended_component(dn, "RMD_LOCAL_USN", &local_usnv);
+       if (ret != LDB_SUCCESS) return ret;
+
+       /* increase the version by 1 */
+       status = dsdb_get_extended_dn_uint32(old_dsdb_dn->dn, &old_version, "RMD_VERSION");
+       if (NT_STATUS_IS_OK(status) && old_version >= version) {
+               version = old_version+1;
+       }
+       vstring = talloc_asprintf(dn, "%lu", (unsigned long)version);
+       vers = data_blob_string_const(vstring);
+       ret = ldb_dn_set_extended_component(dn, "RMD_VERSION", &vers);
+       if (ret != LDB_SUCCESS) return ret;
+
+       dnstring = dsdb_dn_get_extended_linearized(mem_ctx, dsdb_dn, 1);
+       if (dnstring == NULL) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+       *v = data_blob_string_const(dnstring);
+
+       return LDB_SUCCESS;
+}
+
+/*
+  handle adding a linked attribute
+ */
+static int replmd_modify_la_add(struct ldb_module *module,
+                               struct dsdb_schema *schema,
+                               struct ldb_message *msg,
+                               struct ldb_message_element *el,
+                               struct ldb_message_element *old_el,
+                               const struct dsdb_attribute *schema_attr,
+                               uint64_t seq_num,
+                               time_t t,
+                               struct GUID *msg_guid)
+{
+       int i;
+       struct parsed_dn *dns, *old_dns;
+       TALLOC_CTX *tmp_ctx = talloc_new(msg);
+       int ret;
+       struct ldb_val *new_values = NULL;
+       unsigned int num_new_values = 0;
+       unsigned old_num_values = old_el?old_el->num_values:0;
+       const struct GUID *invocation_id;
+       struct ldb_context *ldb = ldb_module_get_ctx(module);
+       NTTIME now;
+
+       unix_to_nt_time(&now, t);
+
+       ret = get_parsed_dns(module, tmp_ctx, el, &dns, schema_attr->syntax->ldap_oid);
        if (ret != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
                return ret;
        }
 
-       /* TODO:
-        * - replace the old object with the newly constructed one
-        */
+       ret = get_parsed_dns(module, tmp_ctx, old_el, &old_dns, schema_attr->syntax->ldap_oid);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
+               return ret;
+       }
 
-       ret = ldb_build_mod_req(&down_req, ldb, ac,
-                               msg,
-                               req->controls,
-                               ac, replmd_op_callback,
-                               req);
+       invocation_id = samdb_ntds_invocation_id(ldb);
+       if (!invocation_id) {
+               talloc_free(tmp_ctx);
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       ret = replmd_check_upgrade_links(old_dns, old_num_values, invocation_id);
        if (ret != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
                return ret;
        }
-       talloc_steal(down_req, msg);
 
-       /* we only change whenChanged and uSNChanged if the seq_num
-          has changed */
-       if (seq_num != 0) {
-               if (add_time_element(msg, "whenChanged", t) != LDB_SUCCESS) {
-                       talloc_free(ac);
-                       return LDB_ERR_OPERATIONS_ERROR;
+       /* for each new value, see if it exists already with the same GUID */
+       for (i=0; i<el->num_values; i++) {
+               struct parsed_dn *p = parsed_dn_find(old_dns, old_num_values, dns[i].guid, NULL);
+               if (p == NULL) {
+                       /* this is a new linked attribute value */
+                       new_values = talloc_realloc(tmp_ctx, new_values, struct ldb_val, num_new_values+1);
+                       if (new_values == NULL) {
+                               ldb_module_oom(module);
+                               talloc_free(tmp_ctx);
+                               return LDB_ERR_OPERATIONS_ERROR;
+                       }
+                       ret = replmd_build_la_val(new_values, &new_values[num_new_values], dns[i].dsdb_dn,
+                                                 invocation_id, seq_num, seq_num, now, 0, false);
+                       if (ret != LDB_SUCCESS) {
+                               talloc_free(tmp_ctx);
+                               return ret;
+                       }
+                       num_new_values++;
+               } else {
+                       /* this is only allowed if the GUID was
+                          previously deleted. */
+                       uint32_t rmd_flags = dsdb_dn_rmd_flags(p->dsdb_dn->dn);
+
+                       if (!(rmd_flags & DSDB_RMD_FLAG_DELETED)) {
+                               ldb_asprintf_errstring(ldb, "Attribute %s already exists for target GUID %s",
+                                                      el->name, GUID_string(tmp_ctx, p->guid));
+                               talloc_free(tmp_ctx);
+                               return LDB_ERR_ATTRIBUTE_OR_VALUE_EXISTS;
+                       }
+                       ret = replmd_update_la_val(old_el->values, p->v, dns[i].dsdb_dn, p->dsdb_dn,
+                                                  invocation_id, seq_num, seq_num, now, 0, false);
+                       if (ret != LDB_SUCCESS) {
+                               talloc_free(tmp_ctx);
+                               return ret;
+                       }
                }
 
-               if (add_uint64_element(msg, "uSNChanged", seq_num) != LDB_SUCCESS) {
-                       talloc_free(ac);
-                       return LDB_ERR_OPERATIONS_ERROR;
+               ret = replmd_add_backlink(module, schema, msg_guid, dns[i].guid, true, schema_attr, true);
+               if (ret != LDB_SUCCESS) {
+                       talloc_free(tmp_ctx);
+                       return ret;
                }
        }
 
-       /* go on with the call chain */
-       return ldb_next_request(module, down_req);
+       /* add the new ones on to the end of the old values, constructing a new el->values */
+       el->values = talloc_realloc(msg->elements, old_el?old_el->values:NULL,
+                                   struct ldb_val,
+                                   old_num_values+num_new_values);
+       if (el->values == NULL) {
+               ldb_module_oom(module);
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       memcpy(&el->values[old_num_values], new_values, num_new_values*sizeof(struct ldb_val));
+       el->num_values = old_num_values + num_new_values;
+
+       talloc_steal(msg->elements, el->values);
+       talloc_steal(el->values, new_values);
+
+       talloc_free(tmp_ctx);
+
+       /* we now tell the backend to replace all existing values
+          with the one we have constructed */
+       el->flags = LDB_FLAG_MOD_REPLACE;
+
+       return LDB_SUCCESS;
 }
 
 
 /*
-  handle a rename request
-
-  On a rename we need to do an extra ldb_modify which sets the
-  whenChanged and uSNChanged attributes
+  handle deleting all active linked attributes
  */
-static int replmd_rename(struct ldb_module *module, struct ldb_request *req)
+static int replmd_modify_la_delete(struct ldb_module *module,
+                                  struct dsdb_schema *schema,
+                                  struct ldb_message *msg,
+                                  struct ldb_message_element *el,
+                                  struct ldb_message_element *old_el,
+                                  const struct dsdb_attribute *schema_attr,
+                                  uint64_t seq_num,
+                                  time_t t,
+                                  struct GUID *msg_guid)
 {
-       struct ldb_context *ldb;
-       int ret, i;
-       time_t t = time(NULL);
-       uint64_t seq_num = 0;
-       struct ldb_message *msg;
-       struct replmd_private *replmd_private = 
-               talloc_get_type(ldb_module_get_private(module), struct replmd_private);
+       int i;
+       struct parsed_dn *dns, *old_dns;
+       TALLOC_CTX *tmp_ctx = talloc_new(msg);
+       int ret;
+       const struct GUID *invocation_id;
+       struct ldb_context *ldb = ldb_module_get_ctx(module);
+       NTTIME now;
+
+       unix_to_nt_time(&now, t);
+
+       /* check if there is nothing to delete */
+       if ((!old_el || old_el->num_values == 0) &&
+           el->num_values == 0) {
+               return LDB_SUCCESS;
+       }
+
+       if (!old_el || old_el->num_values == 0) {
+               return LDB_ERR_NO_SUCH_ATTRIBUTE;
+       }
+
+       ret = get_parsed_dns(module, tmp_ctx, el, &dns, schema_attr->syntax->ldap_oid);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
+               return ret;
+       }
+
+       ret = get_parsed_dns(module, tmp_ctx, old_el, &old_dns, schema_attr->syntax->ldap_oid);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
+               return ret;
+       }
+
+       invocation_id = samdb_ntds_invocation_id(ldb);
+       if (!invocation_id) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       ret = replmd_check_upgrade_links(old_dns, old_el->num_values, invocation_id);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
+               return ret;
+       }
+
+       el->values = NULL;
+
+       /* see if we are being asked to delete any links that
+          don't exist or are already deleted */
+       for (i=0; i<el->num_values; i++) {
+               struct parsed_dn *p = &dns[i];
+               struct parsed_dn *p2;
+               uint32_t rmd_flags;
+
+               p2 = parsed_dn_find(old_dns, old_el->num_values, p->guid, NULL);
+               if (!p2) {
+                       ldb_asprintf_errstring(ldb, "Attribute %s doesn't exist for target GUID %s",
+                                              el->name, GUID_string(tmp_ctx, p->guid));
+                       return LDB_ERR_NO_SUCH_ATTRIBUTE;
+               }
+               rmd_flags = dsdb_dn_rmd_flags(p2->dsdb_dn->dn);
+               if (rmd_flags & DSDB_RMD_FLAG_DELETED) {
+                       ldb_asprintf_errstring(ldb, "Attribute %s already deleted for target GUID %s",
+                                              el->name, GUID_string(tmp_ctx, p->guid));
+                       return LDB_ERR_NO_SUCH_ATTRIBUTE;
+               }
+       }
+
+       /* for each new value, see if it exists already with the same GUID
+          if it is not already deleted and matches the delete list then delete it
+       */
+       for (i=0; i<old_el->num_values; i++) {
+               struct parsed_dn *p = &old_dns[i];
+               uint32_t rmd_flags;
+
+               if (el->num_values && parsed_dn_find(dns, el->num_values, p->guid, NULL) == NULL) {
+                       continue;
+               }
+
+               rmd_flags = dsdb_dn_rmd_flags(p->dsdb_dn->dn);
+               if (rmd_flags & DSDB_RMD_FLAG_DELETED) continue;
+
+               ret = replmd_update_la_val(old_el->values, p->v, p->dsdb_dn, p->dsdb_dn,
+                                          invocation_id, seq_num, seq_num, now, 0, true);
+               if (ret != LDB_SUCCESS) {
+                       talloc_free(tmp_ctx);
+                       return ret;
+               }
+
+               ret = replmd_add_backlink(module, schema, msg_guid, old_dns[i].guid, false, schema_attr, true);
+               if (ret != LDB_SUCCESS) {
+                       talloc_free(tmp_ctx);
+                       return ret;
+               }
+       }
+
+       el->values = talloc_steal(msg->elements, old_el->values);
+       el->num_values = old_el->num_values;
+
+       talloc_free(tmp_ctx);
+
+       /* we now tell the backend to replace all existing values
+          with the one we have constructed */
+       el->flags = LDB_FLAG_MOD_REPLACE;
+
+       return LDB_SUCCESS;
+}
+
+/*
+  handle replacing a linked attribute
+ */
+static int replmd_modify_la_replace(struct ldb_module *module,
+                                   struct dsdb_schema *schema,
+                                   struct ldb_message *msg,
+                                   struct ldb_message_element *el,
+                                   struct ldb_message_element *old_el,
+                                   const struct dsdb_attribute *schema_attr,
+                                   uint64_t seq_num,
+                                   time_t t,
+                                   struct GUID *msg_guid)
+{
+       int i;
+       struct parsed_dn *dns, *old_dns;
+       TALLOC_CTX *tmp_ctx = talloc_new(msg);
+       int ret;
+       const struct GUID *invocation_id;
+       struct ldb_context *ldb = ldb_module_get_ctx(module);
+       struct ldb_val *new_values = NULL;
+       uint32_t num_new_values = 0;
+       unsigned old_num_values = old_el?old_el->num_values:0;
+       NTTIME now;
+
+       unix_to_nt_time(&now, t);
+
+       /* check if there is nothing to replace */
+       if ((!old_el || old_el->num_values == 0) &&
+           el->num_values == 0) {
+               return LDB_SUCCESS;
+       }
+
+       ret = get_parsed_dns(module, tmp_ctx, el, &dns, schema_attr->syntax->ldap_oid);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
+               return ret;
+       }
+
+       ret = get_parsed_dns(module, tmp_ctx, old_el, &old_dns, schema_attr->syntax->ldap_oid);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
+               return ret;
+       }
+
+       invocation_id = samdb_ntds_invocation_id(ldb);
+       if (!invocation_id) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       ret = replmd_check_upgrade_links(old_dns, old_num_values, invocation_id);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
+               return ret;
+       }
+
+       /* mark all the old ones as deleted */
+       for (i=0; i<old_num_values; i++) {
+               struct parsed_dn *old_p = &old_dns[i];
+               struct parsed_dn *p;
+               uint32_t rmd_flags = dsdb_dn_rmd_flags(old_p->dsdb_dn->dn);
+
+               if (rmd_flags & DSDB_RMD_FLAG_DELETED) continue;
+
+               ret = replmd_add_backlink(module, schema, msg_guid, old_dns[i].guid, false, schema_attr, false);
+               if (ret != LDB_SUCCESS) {
+                       talloc_free(tmp_ctx);
+                       return ret;
+               }
+
+               p = parsed_dn_find(dns, el->num_values, old_p->guid, NULL);
+               if (p) {
+                       /* we don't delete it if we are re-adding it */
+                       continue;
+               }
+
+               ret = replmd_update_la_val(old_el->values, old_p->v, old_p->dsdb_dn, old_p->dsdb_dn,
+                                          invocation_id, seq_num, seq_num, now, 0, true);
+               if (ret != LDB_SUCCESS) {
+                       talloc_free(tmp_ctx);
+                       return ret;
+               }
+       }
+
+       /* for each new value, either update its meta-data, or add it
+        * to old_el
+       */
+       for (i=0; i<el->num_values; i++) {
+               struct parsed_dn *p = &dns[i], *old_p;
+
+               if (old_dns &&
+                   (old_p = parsed_dn_find(old_dns,
+                                           old_num_values, p->guid, NULL)) != NULL) {
+                       /* update in place */
+                       ret = replmd_update_la_val(old_el->values, old_p->v, old_p->dsdb_dn,
+                                                  old_p->dsdb_dn, invocation_id,
+                                                  seq_num, seq_num, now, 0, false);
+                       if (ret != LDB_SUCCESS) {
+                               talloc_free(tmp_ctx);
+                               return ret;
+                       }
+               } else {
+                       /* add a new one */
+                       new_values = talloc_realloc(tmp_ctx, new_values, struct ldb_val,
+                                                   num_new_values+1);
+                       if (new_values == NULL) {
+                               ldb_module_oom(module);
+                               talloc_free(tmp_ctx);
+                               return LDB_ERR_OPERATIONS_ERROR;
+                       }
+                       ret = replmd_build_la_val(new_values, &new_values[num_new_values], dns[i].dsdb_dn,
+                                                 invocation_id, seq_num, seq_num, now, 0, false);
+                       if (ret != LDB_SUCCESS) {
+                               talloc_free(tmp_ctx);
+                               return ret;
+                       }
+                       num_new_values++;
+               }
+
+               ret = replmd_add_backlink(module, schema, msg_guid, dns[i].guid, true, schema_attr, false);
+               if (ret != LDB_SUCCESS) {
+                       talloc_free(tmp_ctx);
+                       return ret;
+               }
+       }
+
+       /* add the new values to the end of old_el */
+       if (num_new_values != 0) {
+               el->values = talloc_realloc(msg->elements, old_el?old_el->values:NULL,
+                                           struct ldb_val, old_num_values+num_new_values);
+               if (el->values == NULL) {
+                       ldb_module_oom(module);
+                       return LDB_ERR_OPERATIONS_ERROR;
+               }
+               memcpy(&el->values[old_num_values], &new_values[0],
+                      sizeof(struct ldb_val)*num_new_values);
+               el->num_values = old_num_values + num_new_values;
+               talloc_steal(msg->elements, new_values);
+       } else {
+               el->values = old_el->values;
+               el->num_values = old_el->num_values;
+               talloc_steal(msg->elements, el->values);
+       }
+
+       talloc_free(tmp_ctx);
+
+       /* we now tell the backend to replace all existing values
+          with the one we have constructed */
+       el->flags = LDB_FLAG_MOD_REPLACE;
+
+       return LDB_SUCCESS;
+}
+
+
+/*
+  handle linked attributes in modify requests
+ */
+static int replmd_modify_handle_linked_attribs(struct ldb_module *module,
+                                              struct ldb_message *msg,
+                                              uint64_t seq_num, time_t t)
+{
+       struct ldb_result *res;
+       int ret, i;
+       struct ldb_context *ldb = ldb_module_get_ctx(module);
+       struct ldb_message *old_msg;
+       struct dsdb_schema *schema = dsdb_get_schema(ldb);
+       struct GUID old_guid;
+
+       if (seq_num == 0) {
+               /* there the replmd_update_rpmd code has already
+                * checked and saw that there are no linked
+                * attributes */
+               return LDB_SUCCESS;
+       }
+
+#if !W2K3_LINKED_ATTRIBUTES
+       return LDB_SUCCESS;
+#endif
+
+       if (dsdb_functional_level(ldb) == DS_DOMAIN_FUNCTION_2000) {
+               /* don't do anything special for linked attributes */
+               return LDB_SUCCESS;
+       }
+
+       ret = dsdb_module_search_dn(module, msg, &res, msg->dn, NULL,
+                                   DSDB_SEARCH_SHOW_DELETED |
+                                   DSDB_SEARCH_REVEAL_INTERNALS |
+                                   DSDB_SEARCH_SHOW_DN_IN_STORAGE_FORMAT);
+       if (ret != LDB_SUCCESS) {
+               return ret;
+       }
+       old_msg = res->msgs[0];
+
+       old_guid = samdb_result_guid(old_msg, "objectGUID");
+
+       for (i=0; i<msg->num_elements; i++) {
+               struct ldb_message_element *el = &msg->elements[i];
+               struct ldb_message_element *old_el, *new_el;
+               const struct dsdb_attribute *schema_attr
+                       = dsdb_attribute_by_lDAPDisplayName(schema, el->name);
+               if (!schema_attr) {
+                       ldb_asprintf_errstring(ldb,
+                                              "attribute %s is not a valid attribute in schema", el->name);
+                       return LDB_ERR_OBJECT_CLASS_VIOLATION;
+               }
+               if (schema_attr->linkID == 0) {
+                       continue;
+               }
+               if ((schema_attr->linkID & 1) == 1) {
+                       /* Odd is for the target.  Illegal to modify */
+                       ldb_asprintf_errstring(ldb,
+                                              "attribute %s must not be modified directly, it is a linked attribute", el->name);
+                       return LDB_ERR_UNWILLING_TO_PERFORM;
+               }
+               old_el = ldb_msg_find_element(old_msg, el->name);
+               switch (el->flags & LDB_FLAG_MOD_MASK) {
+               case LDB_FLAG_MOD_REPLACE:
+                       ret = replmd_modify_la_replace(module, schema, msg, el, old_el, schema_attr, seq_num, t, &old_guid);
+                       break;
+               case LDB_FLAG_MOD_DELETE:
+                       ret = replmd_modify_la_delete(module, schema, msg, el, old_el, schema_attr, seq_num, t, &old_guid);
+                       break;
+               case LDB_FLAG_MOD_ADD:
+                       ret = replmd_modify_la_add(module, schema, msg, el, old_el, schema_attr, seq_num, t, &old_guid);
+                       break;
+               default:
+                       ldb_asprintf_errstring(ldb,
+                                              "invalid flags 0x%x for %s linked attribute",
+                                              el->flags, el->name);
+                       return LDB_ERR_UNWILLING_TO_PERFORM;
+               }
+               if (ret != LDB_SUCCESS) {
+                       return ret;
+               }
+               if (old_el) {
+                       ldb_msg_remove_attr(old_msg, el->name);
+               }
+               ldb_msg_add_empty(old_msg, el->name, 0, &new_el);
+               new_el->num_values = el->num_values;
+               new_el->values = talloc_steal(msg->elements, el->values);
+
+               /* TODO: this relises a bit too heavily on the exact
+                  behaviour of ldb_msg_find_element and
+                  ldb_msg_remove_element */
+               old_el = ldb_msg_find_element(msg, el->name);
+               if (old_el != el) {
+                       ldb_msg_remove_element(msg, old_el);
+                       i--;
+               }
+       }
+
+       talloc_free(res);
+       return ret;
+}
+
+
+
+static int replmd_modify(struct ldb_module *module, struct ldb_request *req)
+{
+       struct ldb_context *ldb;
+       struct replmd_replicated_request *ac;
+       struct ldb_request *down_req;
+       struct ldb_message *msg;
+       time_t t = time(NULL);
+       int ret;
+       bool is_urgent = false;
+
+       /* do not manipulate our control entries */
+       if (ldb_dn_is_special(req->op.mod.message->dn)) {
+               return ldb_next_request(module, req);
+       }
+
+       ldb = ldb_module_get_ctx(module);
+
+       ldb_debug(ldb, LDB_DEBUG_TRACE, "replmd_modify\n");
+
+       ac = replmd_ctx_init(module, req);
+       if (!ac) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       /* we have to copy the message as the caller might have it as a const */
+       msg = ldb_msg_copy_shallow(ac, req->op.mod.message);
+       if (msg == NULL) {
+               ldb_oom(ldb);
+               talloc_free(ac);
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       ldb_msg_remove_attr(msg, "whenChanged");
+       ldb_msg_remove_attr(msg, "uSNChanged");
+
+       ret = replmd_update_rpmd(module, ac->schema, msg, &ac->seq_num, t, &is_urgent);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(ac);
+               return ret;
+       }
+
+       ret = replmd_modify_handle_linked_attribs(module, msg, ac->seq_num, t);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(ac);
+               return ret;
+       }
+
+       /* TODO:
+        * - replace the old object with the newly constructed one
+        */
+
+       ac->is_urgent = is_urgent;
+
+       ret = ldb_build_mod_req(&down_req, ldb, ac,
+                               msg,
+                               req->controls,
+                               ac, replmd_op_callback,
+                               req);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(ac);
+               return ret;
+       }
+       talloc_steal(down_req, msg);
+
+       /* we only change whenChanged and uSNChanged if the seq_num
+          has changed */
+       if (ac->seq_num != 0) {
+               if (add_time_element(msg, "whenChanged", t) != LDB_SUCCESS) {
+                       talloc_free(ac);
+                       return ret;
+               }
+
+               if (add_uint64_element(msg, "uSNChanged", ac->seq_num) != LDB_SUCCESS) {
+                       talloc_free(ac);
+                       return ret;
+               }
+       }
+
+       /* go on with the call chain */
+       return ldb_next_request(module, down_req);
+}
+
+static int replmd_rename_callback(struct ldb_request *req, struct ldb_reply *ares);
+
+/*
+  handle a rename request
+
+  On a rename we need to do an extra ldb_modify which sets the
+  whenChanged and uSNChanged attributes.  We do this in a callback after the success.
+ */
+static int replmd_rename(struct ldb_module *module, struct ldb_request *req)
+{
+       struct ldb_context *ldb;
+       struct replmd_replicated_request *ac;
+       int ret;
+       struct ldb_request *down_req;
+
+       /* do not manipulate our control entries */
+       if (ldb_dn_is_special(req->op.mod.message->dn)) {
+               return ldb_next_request(module, req);
+       }
+
+       ldb = ldb_module_get_ctx(module);
+
+       ldb_debug(ldb, LDB_DEBUG_TRACE, "replmd_rename\n");
+
+       ac = replmd_ctx_init(module, req);
+       if (!ac) {
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+       ret = ldb_build_rename_req(&down_req, ldb, ac,
+                                  ac->req->op.rename.olddn,
+                                  ac->req->op.rename.newdn,
+                                  ac->req->controls,
+                                  ac, replmd_rename_callback,
+                                  ac->req);
+
+       if (ret != LDB_SUCCESS) {
+               talloc_free(ac);
+               return ret;
+       }
+
+       /* go on with the call chain */
+       return ldb_next_request(module, down_req);
+}
+
+/* After the rename is compleated, update the whenchanged etc */
+static int replmd_rename_callback(struct ldb_request *req, struct ldb_reply *ares)
+{
+       struct ldb_context *ldb;
+       struct replmd_replicated_request *ac;
+       struct ldb_request *down_req;
+       struct ldb_message *msg;
+       time_t t = time(NULL);
+       int ret;
+
+       ac = talloc_get_type(req->context, struct replmd_replicated_request);
+       ldb = ldb_module_get_ctx(ac->module);
+
+       if (ares->error != LDB_SUCCESS) {
+               return ldb_module_done(ac->req, ares->controls,
+                                       ares->response, ares->error);
+       }
+
+       if (ares->type != LDB_REPLY_DONE) {
+               ldb_set_errstring(ldb,
+                                 "invalid ldb_reply_type in callback");
+               talloc_free(ares);
+               return ldb_module_done(ac->req, NULL, NULL,
+                                       LDB_ERR_OPERATIONS_ERROR);
+       }
+
+       /* Get a sequence number from the backend */
+       ret = ldb_sequence_number(ldb, LDB_SEQ_NEXT, &ac->seq_num);
+       if (ret != LDB_SUCCESS) {
+               return ret;
+       }
+
+       /* TODO:
+        * - replace the old object with the newly constructed one
+        */
+
+       msg = ldb_msg_new(ac);
+       if (msg == NULL) {
+               ldb_oom(ldb);
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       msg->dn = ac->req->op.rename.newdn;
+
+       ret = ldb_build_mod_req(&down_req, ldb, ac,
+                               msg,
+                               req->controls,
+                               ac, replmd_op_callback,
+                               req);
+
+       if (ret != LDB_SUCCESS) {
+               talloc_free(ac);
+               return ret;
+       }
+       talloc_steal(down_req, msg);
+
+       if (add_time_element(msg, "whenChanged", t) != LDB_SUCCESS) {
+               talloc_free(ac);
+               return ret;
+       }
+       
+       if (add_uint64_element(msg, "uSNChanged", ac->seq_num) != LDB_SUCCESS) {
+               talloc_free(ac);
+               return ret;
+       }
+
+       /* go on with the call chain - do the modify after the rename */
+       return ldb_next_request(ac->module, down_req);
+}
+
+/*
+   remove links from objects that point at this object when an object
+   is deleted
+ */
+static int replmd_delete_remove_link(struct ldb_module *module,
+                                    struct dsdb_schema *schema,
+                                    struct ldb_dn *dn,
+                                    struct ldb_message_element *el,
+                                    const struct dsdb_attribute *sa)
+{
+       int i;
+       TALLOC_CTX *tmp_ctx = talloc_new(module);
+       struct ldb_context *ldb = ldb_module_get_ctx(module);
+
+       for (i=0; i<el->num_values; i++) {
+               struct dsdb_dn *dsdb_dn;
+               NTSTATUS status;
+               int ret;
+               struct GUID guid2;
+               struct ldb_message *msg;
+               const struct dsdb_attribute *target_attr;
+               struct ldb_message_element *el2;
+               struct ldb_val dn_val;
+
+               if (dsdb_dn_is_deleted_val(&el->values[i])) {
+                       continue;
+               }
+
+               dsdb_dn = dsdb_dn_parse(tmp_ctx, ldb, &el->values[i], sa->syntax->ldap_oid);
+               if (!dsdb_dn) {
+                       talloc_free(tmp_ctx);
+                       return LDB_ERR_OPERATIONS_ERROR;
+               }
+
+               status = dsdb_get_extended_dn_guid(dsdb_dn->dn, &guid2, "GUID");
+               if (!NT_STATUS_IS_OK(status)) {
+                       talloc_free(tmp_ctx);
+                       return LDB_ERR_OPERATIONS_ERROR;
+               }
+
+               /* remove the link */
+               msg = ldb_msg_new(tmp_ctx);
+               if (!msg) {
+                       ldb_module_oom(module);
+                       talloc_free(tmp_ctx);
+                       return LDB_ERR_OPERATIONS_ERROR;
+               }
+
+
+               msg->dn = dsdb_dn->dn;
+
+               target_attr = dsdb_attribute_by_linkID(schema, sa->linkID ^ 1);
+               if (target_attr == NULL) {
+                       continue;
+               }
+
+               ret = ldb_msg_add_empty(msg, target_attr->lDAPDisplayName, LDB_FLAG_MOD_DELETE, &el2);
+               if (ret != LDB_SUCCESS) {
+                       ldb_module_oom(module);
+                       talloc_free(tmp_ctx);
+                       return LDB_ERR_OPERATIONS_ERROR;
+               }
+               dn_val = data_blob_string_const(ldb_dn_get_linearized(dn));
+               el2->values = &dn_val;
+               el2->num_values = 1;
+
+               ret = dsdb_module_modify(module, msg, DSDB_FLAG_OWN_MODULE);
+               if (ret != LDB_SUCCESS) {
+                       talloc_free(tmp_ctx);
+                       return ret;
+               }
+       }
+       talloc_free(tmp_ctx);
+       return LDB_SUCCESS;
+}
+
+
+/*
+  handle update of replication meta data for deletion of objects
+
+  This also handles the mapping of delete to a rename operation
+  to allow deletes to be replicated.
+ */
+static int replmd_delete(struct ldb_module *module, struct ldb_request *req)
+{
+       int ret = LDB_ERR_OTHER;
+       bool retb;
+       struct ldb_dn *old_dn, *new_dn;
+       const char *rdn_name;
+       const struct ldb_val *rdn_value, *new_rdn_value;
+       struct GUID guid;
+       struct ldb_context *ldb = ldb_module_get_ctx(module);
+       struct dsdb_schema *schema = dsdb_get_schema(ldb);
+       struct ldb_message *msg, *old_msg;
+       struct ldb_message_element *el;
+       TALLOC_CTX *tmp_ctx;
+       struct ldb_result *res, *parent_res;
+       const char *preserved_attrs[] = {
+               /* yes, this really is a hard coded list. See MS-ADTS
+                  section 3.1.1.5.5.1.1 */
+               "nTSecurityDescriptor", "attributeID", "attributeSyntax", "dNReferenceUpdate", "dNSHostName",
+               "flatName", "governsID", "groupType", "instanceType", "lDAPDisplayName", "legacyExchangeDN",
+               "isDeleted", "isRecycled", "lastKnownParent", "msDS-LastKnownRDN", "mS-DS-CreatorSID",
+               "mSMQOwnerID", "nCName", "objectClass", "distinguishedName", "objectGUID", "objectSid",
+               "oMSyntax", "proxiedObjectName", "name", "replPropertyMetaData", "sAMAccountName",
+               "securityIdentifier", "sIDHistory", "subClassOf", "systemFlags", "trustPartner", "trustDirection",
+               "trustType", "trustAttributes", "userAccountControl", "uSNChanged", "uSNCreated", "whenCreated",
+               "whenChanged", NULL};
+       uint32_t el_count = 0;
+       int i;
+
+       if (ldb_dn_is_special(req->op.del.dn)) {
+               return ldb_next_request(module, req);
+       }
+
+       tmp_ctx = talloc_new(ldb);
+
+       old_dn = ldb_dn_copy(tmp_ctx, req->op.del.dn);
+
+       /* we need the complete msg off disk, so we can work out which
+          attributes need to be removed */
+       ret = dsdb_module_search_dn(module, tmp_ctx, &res, old_dn, NULL,
+                                   DSDB_SEARCH_SHOW_DELETED |
+                                   DSDB_SEARCH_REVEAL_INTERNALS |
+                                   DSDB_SEARCH_SHOW_DN_IN_STORAGE_FORMAT);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
+               return ret;
+       }
+       old_msg = res->msgs[0];
+
+       if (ldb_msg_check_string_attribute(old_msg, "isDeleted", "TRUE")) {
+               struct auth_session_info *session_info =
+                       (struct auth_session_info *)ldb_get_opaque(ldb, "sessionInfo");
+               if (security_session_user_level(session_info) != SECURITY_SYSTEM) {
+                       ldb_asprintf_errstring(ldb, "Refusing to delete deleted object %s",
+                                              ldb_dn_get_linearized(old_msg->dn));
+                       return LDB_ERR_UNWILLING_TO_PERFORM;
+               }
+
+               /* it is already deleted - really remove it this time */
+               talloc_free(tmp_ctx);
+               return ldb_next_request(module, req);
+       }
+
+       /* work out where we will be renaming this object to */
+       ret = dsdb_get_deleted_objects_dn(ldb, tmp_ctx, old_dn, &new_dn);
+       if (ret != LDB_SUCCESS) {
+               /* this is probably an attempted delete on a partition
+                * that doesn't allow delete operations, such as the
+                * schema partition */
+               ldb_asprintf_errstring(ldb, "No Deleted Objects container for DN %s",
+                                      ldb_dn_get_linearized(old_dn));
+               talloc_free(tmp_ctx);
+               return LDB_ERR_UNWILLING_TO_PERFORM;
+       }
+
+       rdn_name = ldb_dn_get_rdn_name(old_dn);
+       rdn_value = ldb_dn_get_rdn_val(old_dn);
+
+       /* get the objects GUID from the search we just did */
+       guid = samdb_result_guid(old_msg, "objectGUID");
+
+       /* Add a formatted child */
+       retb = ldb_dn_add_child_fmt(new_dn, "%s=%s\\0ADEL:%s",
+                                   rdn_name,
+                                   rdn_value->data,
+                                   GUID_string(tmp_ctx, &guid));
+       if (!retb) {
+               DEBUG(0,(__location__ ": Unable to add a formatted child to dn: %s",
+                               ldb_dn_get_linearized(new_dn)));
+               talloc_free(tmp_ctx);
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       /*
+         now we need to modify the object in the following ways:
+
+         - add isDeleted=TRUE
+         - update rDN and name, with new rDN
+         - remove linked attributes
+         - remove objectCategory and sAMAccountType
+         - remove attribs not on the preserved list
+            - preserved if in above list, or is rDN
+         - remove all linked attribs from this object
+         - remove all links from other objects to this object
+         - add lastKnownParent
+         - update replPropertyMetaData?
+
+         see MS-ADTS "Tombstone Requirements" section 3.1.1.5.5.1.1
+        */
+
+       msg = ldb_msg_new(tmp_ctx);
+       if (msg == NULL) {
+               ldb_module_oom(module);
+               talloc_free(tmp_ctx);
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       msg->dn = old_dn;
+
+       ret = ldb_msg_add_string(msg, "isDeleted", "TRUE");
+       if (ret != LDB_SUCCESS) {
+               DEBUG(0,(__location__ ": Failed to add isDeleted string to the msg\n"));
+               ldb_module_oom(module);
+               talloc_free(tmp_ctx);
+               return ret;
+       }
+       msg->elements[el_count++].flags = LDB_FLAG_MOD_ADD;
+
+       /* we also mark it as recycled, meaning this object can't be
+          recovered (we are stripping its attributes) */
+       if (dsdb_functional_level(ldb) >= DS_DOMAIN_FUNCTION_2008_R2) {
+               ret = ldb_msg_add_string(msg, "isRecycled", "TRUE");
+               if (ret != LDB_SUCCESS) {
+                       DEBUG(0,(__location__ ": Failed to add isRecycled string to the msg\n"));
+                       ldb_module_oom(module);
+                       talloc_free(tmp_ctx);
+                       return ret;
+               }
+               msg->elements[el_count++].flags = LDB_FLAG_MOD_ADD;
+       }
+
+       /* we need the storage form of the parent GUID */
+       ret = dsdb_module_search_dn(module, tmp_ctx, &parent_res,
+                                   ldb_dn_get_parent(tmp_ctx, old_dn), NULL,
+                                   DSDB_SEARCH_SHOW_DN_IN_STORAGE_FORMAT |
+                                   DSDB_SEARCH_REVEAL_INTERNALS);
+       if (ret != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
+               return ret;
+       }
+
+       ret = ldb_msg_add_steal_string(msg, "lastKnownParent",
+                                      ldb_dn_get_extended_linearized(tmp_ctx, parent_res->msgs[0]->dn, 1));
+       if (ret != LDB_SUCCESS) {
+               DEBUG(0,(__location__ ": Failed to add lastKnownParent string to the msg\n"));
+               ldb_module_oom(module);
+               talloc_free(tmp_ctx);
+               return ret;
+       }
+       msg->elements[el_count++].flags = LDB_FLAG_MOD_ADD;
+
+       /* work out which of the old attributes we will be removing */
+       for (i=0; i<old_msg->num_elements; i++) {
+               const struct dsdb_attribute *sa;
+               el = &old_msg->elements[i];
+               sa = dsdb_attribute_by_lDAPDisplayName(schema, el->name);
+               if (!sa) {
+                       talloc_free(tmp_ctx);
+                       return LDB_ERR_OPERATIONS_ERROR;
+               }
+               if (ldb_attr_cmp(el->name, rdn_name) == 0) {
+                       /* don't remove the rDN */
+                       continue;
+               }
 
-       /* do not manipulate our control entries */
-       if (ldb_dn_is_special(req->op.mod.message->dn)) {
-               return ldb_next_request(module, req);
-       }
+               if (sa->linkID && sa->linkID & 1) {
+                       ret = replmd_delete_remove_link(module, schema, old_dn, el, sa);
+                       if (ret != LDB_SUCCESS) {
+                               talloc_free(tmp_ctx);
+                               return LDB_ERR_OPERATIONS_ERROR;
+                       }
+                       continue;
+               }
 
-       ldb = ldb_module_get_ctx(module);
+               if (!sa->linkID && ldb_attr_in_list(preserved_attrs, el->name)) {
+                       continue;
+               }
 
-       ldb_debug(ldb, LDB_DEBUG_TRACE, "replmd_rename\n");
+               ret = ldb_msg_add_empty(msg, el->name, LDB_FLAG_MOD_DELETE, &el);
+               if (ret != LDB_SUCCESS) {
+                       talloc_free(tmp_ctx);
+                       ldb_module_oom(module);
+                       return ret;
+               }
+       }
 
-       /* Get a sequence number from the backend */
-       ret = ldb_sequence_number(ldb, LDB_SEQ_NEXT, &seq_num);
+       /* work out what the new rdn value is, for updating the
+          rDN and name fields */
+       new_rdn_value = ldb_dn_get_rdn_val(new_dn);
+       ret = ldb_msg_add_value(msg, rdn_name, new_rdn_value, &el);
        if (ret != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
                return ret;
        }
+       el->flags = LDB_FLAG_MOD_REPLACE;
 
-       msg = ldb_msg_new(req);
-       if (msg == NULL) {
-               ldb_oom(ldb);
-               return LDB_ERR_OPERATIONS_ERROR;
-       }
-
-       msg->dn = req->op.rename.olddn;
-
-       if (add_time_element(msg, "whenChanged", t) != LDB_SUCCESS) {
-               talloc_free(msg);
-               return LDB_ERR_OPERATIONS_ERROR;
-       }
-       msg->elements[0].flags = LDB_FLAG_MOD_REPLACE;
-
-       if (add_uint64_element(msg, "uSNChanged", seq_num) != LDB_SUCCESS) {
-               talloc_free(msg);
-               return LDB_ERR_OPERATIONS_ERROR;
+       el = ldb_msg_find_element(old_msg, "name");
+       if (el) {
+               ret = ldb_msg_add_value(msg, "name", new_rdn_value, &el);
+               if (ret != LDB_SUCCESS) {
+                       talloc_free(tmp_ctx);
+                       return ret;
+               }
+               el->flags = LDB_FLAG_MOD_REPLACE;
        }
-       msg->elements[1].flags = LDB_FLAG_MOD_REPLACE;
 
-       ret = ldb_modify(ldb, msg);
-       talloc_free(msg);
+       ret = dsdb_module_modify(module, msg, DSDB_FLAG_OWN_MODULE);
        if (ret != LDB_SUCCESS) {
+               ldb_asprintf_errstring(ldb, "replmd_delete: Failed to modify object %s in delete - %s",
+                                      ldb_dn_get_linearized(old_dn), ldb_errstring(ldb));
+               talloc_free(tmp_ctx);
                return ret;
        }
 
-       ret = replmd_load_NCs(module);
-       if (ret != 0) {
+       /* now rename onto the new DN */
+       ret = dsdb_module_rename(module, old_dn, new_dn, 0);
+       if (ret != LDB_SUCCESS){
+               DEBUG(0,(__location__ ": Failed to rename object from '%s' to '%s' - %s\n",
+                        ldb_dn_get_linearized(old_dn),
+                        ldb_dn_get_linearized(new_dn),
+                        ldb_errstring(ldb)));
+               talloc_free(tmp_ctx);
                return ret;
        }
 
-       /* now update the highest uSNs of the partitions that are
-          affected. Note that two partitions could be changing */
-       for (i=0; i<replmd_private->num_ncs; i++) {
-               if (ldb_dn_compare_base(replmd_private->ncs[i].dn, 
-                                       req->op.rename.olddn) == 0) {
-                       break;
-               }
-       }
-       if (i == replmd_private->num_ncs) {
-               DEBUG(0,(__location__ ": rename olddn outside tree? %s\n",
-                        ldb_dn_get_linearized(req->op.rename.olddn)));
-               return LDB_ERR_OPERATIONS_ERROR;
-       }
-       replmd_private->ncs[i].mod_usn = seq_num;
+       talloc_free(tmp_ctx);
 
-       for (i=0; i<replmd_private->num_ncs; i++) {
-               if (ldb_dn_compare_base(replmd_private->ncs[i].dn, 
-                                       req->op.rename.newdn) == 0) {
-                       break;
-               }
-       }
-       if (i == replmd_private->num_ncs) {
-               DEBUG(0,(__location__ ": rename newdn outside tree? %s\n",
-                        ldb_dn_get_linearized(req->op.rename.newdn)));
-               return LDB_ERR_OPERATIONS_ERROR;
-       }
-       replmd_private->ncs[i].mod_usn = seq_num;
-       
-       /* go on with the call chain */
-       return ldb_next_request(module, req);
+       return ldb_module_done(req, NULL, NULL, LDB_SUCCESS);
 }
 
 
+
 static int replmd_replicated_request_error(struct replmd_replicated_request *ar, int ret)
 {
        return ret;
@@ -1071,44 +2526,6 @@ static int replmd_replicated_request_werror(struct replmd_replicated_request *ar
        return ret;
 }
 
-static int replmd_replicated_apply_next(struct replmd_replicated_request *ar);
-
-static int replmd_replicated_apply_add_callback(struct ldb_request *req,
-                                               struct ldb_reply *ares)
-{
-       struct ldb_context *ldb;
-       struct replmd_replicated_request *ar = talloc_get_type(req->context,
-                                              struct replmd_replicated_request);
-       int ret;
-
-       ldb = ldb_module_get_ctx(ar->module);
-
-       if (!ares) {
-               return ldb_module_done(ar->req, NULL, NULL,
-                                       LDB_ERR_OPERATIONS_ERROR);
-       }
-       if (ares->error != LDB_SUCCESS) {
-               return ldb_module_done(ar->req, ares->controls,
-                                       ares->response, ares->error);
-       }
-
-       if (ares->type != LDB_REPLY_DONE) {
-               ldb_set_errstring(ldb, "Invalid reply type\n!");
-               return ldb_module_done(ar->req, NULL, NULL,
-                                       LDB_ERR_OPERATIONS_ERROR);
-       }
-
-       talloc_free(ares);
-       ar->index_current++;
-
-       ret = replmd_replicated_apply_next(ar);
-       if (ret != LDB_SUCCESS) {
-               return ldb_module_done(ar->req, NULL, NULL, ret);
-       }
-
-       return LDB_SUCCESS;
-}
-
 static int replmd_replicated_apply_add(struct replmd_replicated_request *ar)
 {
        struct ldb_context *ldb;
@@ -1118,7 +2535,6 @@ static int replmd_replicated_apply_add(struct replmd_replicated_request *ar)
        struct replPropertyMetaDataBlob *md;
        struct ldb_val md_value;
        uint32_t i;
-       uint64_t seq_num;
        int ret;
 
        /*
@@ -1134,7 +2550,7 @@ static int replmd_replicated_apply_add(struct replmd_replicated_request *ar)
        msg = ar->objs->objects[ar->index_current].msg;
        md = ar->objs->objects[ar->index_current].meta_data;
 
-       ret = ldb_sequence_number(ldb, LDB_SEQ_NEXT, &seq_num);
+       ret = ldb_sequence_number(ldb, LDB_SEQ_NEXT, &ar->seq_num);
        if (ret != LDB_SUCCESS) {
                return replmd_replicated_request_error(ar, ret);
        }
@@ -1149,31 +2565,27 @@ static int replmd_replicated_apply_add(struct replmd_replicated_request *ar)
                return replmd_replicated_request_error(ar, ret);
        }
 
-       ret = samdb_msg_add_uint64(ldb, msg, msg, "uSNCreated", seq_num);
-       if (ret != LDB_SUCCESS) {
-               return replmd_replicated_request_error(ar, ret);
-       }
-
-       ret = samdb_msg_add_uint64(ldb, msg, msg, "uSNChanged", seq_num);
+       ret = samdb_msg_add_uint64(ldb, msg, msg, "uSNCreated", ar->seq_num);
        if (ret != LDB_SUCCESS) {
                return replmd_replicated_request_error(ar, ret);
        }
 
-       ret = replmd_notify(ar->module, msg->dn, seq_num);
+       ret = samdb_msg_add_uint64(ldb, msg, msg, "uSNChanged", ar->seq_num);
        if (ret != LDB_SUCCESS) {
                return replmd_replicated_request_error(ar, ret);
        }
 
        /* remove any message elements that have zero values */
        for (i=0; i<msg->num_elements; i++) {
-               if (msg->elements[i].num_values == 0) {
+               struct ldb_message_element *el = &msg->elements[i];
+
+               if (el->num_values == 0) {
                        DEBUG(4,(__location__ ": Removing attribute %s with num_values==0\n",
-                                msg->elements[i].name));
-                       memmove(&msg->elements[i], 
-                               &msg->elements[i+1], 
-                               sizeof(msg->elements[i])*(msg->num_elements - (i+1)));
+                                el->name));
+                       memmove(el, el+1, sizeof(*el)*(msg->num_elements - (i+1)));
                        msg->num_elements--;
                        i--;
+                       continue;
                }
        }
        
@@ -1181,7 +2593,7 @@ static int replmd_replicated_apply_add(struct replmd_replicated_request *ar)
         * the meta data array is already sorted by the caller
         */
        for (i=0; i < md->ctr.ctr1.count; i++) {
-               md->ctr.ctr1.array[i].local_usn = seq_num;
+               md->ctr.ctr1.array[i].local_usn = ar->seq_num;
        }
        ndr_err = ndr_push_struct_blob(&md_value, msg, 
                                       lp_iconv_convenience(ldb_get_opaque(ldb, "loadparm")),
@@ -1210,68 +2622,45 @@ static int replmd_replicated_apply_add(struct replmd_replicated_request *ar)
                                msg,
                                ar->controls,
                                ar,
-                               replmd_replicated_apply_add_callback,
+                               replmd_op_callback,
                                ar->req);
        if (ret != LDB_SUCCESS) return replmd_replicated_request_error(ar, ret);
 
        return ldb_next_request(ar->module, change_req);
 }
 
-static int replmd_replPropertyMetaData1_conflict_compare(struct replPropertyMetaData1 *m1,
-                                                        struct replPropertyMetaData1 *m2)
+/*
+   return true if an update is newer than an existing entry
+   see section 5.11 of MS-ADTS
+*/
+static bool replmd_update_is_newer(const struct GUID *current_invocation_id,
+                                  const struct GUID *update_invocation_id,
+                                  uint32_t current_version,
+                                  uint32_t update_version,
+                                  NTTIME current_change_time,
+                                  NTTIME update_change_time)
 {
-       int ret;
-
-       if (m1->version != m2->version) {
-               return m1->version - m2->version;
+       if (update_version != current_version) {
+               return update_version > current_version;
        }
-
-       if (m1->originating_change_time != m2->originating_change_time) {
-               return m1->originating_change_time - m2->originating_change_time;
+       if (update_change_time > current_change_time) {
+               return true;
        }
-
-       ret = GUID_compare(&m1->originating_invocation_id, &m2->originating_invocation_id);
-       if (ret != 0) {
-               return ret;
+       if (update_change_time == current_change_time) {
+               return GUID_compare(update_invocation_id, current_invocation_id) > 0;
        }
-
-       return m1->originating_usn - m2->originating_usn;
+       return false;
 }
 
-static int replmd_replicated_apply_merge_callback(struct ldb_request *req,
-                                                 struct ldb_reply *ares)
+static bool replmd_replPropertyMetaData1_is_newer(struct replPropertyMetaData1 *cur_m,
+                                                 struct replPropertyMetaData1 *new_m)
 {
-       struct ldb_context *ldb;
-       struct replmd_replicated_request *ar = talloc_get_type(req->context,
-                                              struct replmd_replicated_request);
-       int ret;
-
-       ldb = ldb_module_get_ctx(ar->module);
-
-       if (!ares) {
-               return ldb_module_done(ar->req, NULL, NULL,
-                                       LDB_ERR_OPERATIONS_ERROR);
-       }
-       if (ares->error != LDB_SUCCESS) {
-               return ldb_module_done(ar->req, ares->controls,
-                                       ares->response, ares->error);
-       }
-
-       if (ares->type != LDB_REPLY_DONE) {
-               ldb_set_errstring(ldb, "Invalid reply type\n!");
-               return ldb_module_done(ar->req, NULL, NULL,
-                                       LDB_ERR_OPERATIONS_ERROR);
-       }
-
-       talloc_free(ares);
-       ar->index_current++;
-
-       ret = replmd_replicated_apply_next(ar);
-       if (ret != LDB_SUCCESS) {
-               return ldb_module_done(ar->req, NULL, NULL, ret);
-       }
-
-       return LDB_SUCCESS;
+       return replmd_update_is_newer(&cur_m->originating_invocation_id,
+                                     &new_m->originating_invocation_id,
+                                     cur_m->version,
+                                     new_m->version,
+                                     cur_m->originating_change_time,
+                                     new_m->originating_change_time);
 }
 
 static int replmd_replicated_apply_merge(struct replmd_replicated_request *ar)
@@ -1287,7 +2676,6 @@ static int replmd_replicated_apply_merge(struct replmd_replicated_request *ar)
        struct ldb_val nmd_value;
        uint32_t i,j,ni=0;
        uint32_t removed_attrs = 0;
-       uint64_t seq_num;
        int ret;
 
        ldb = ldb_module_get_ctx(ar->module);
@@ -1303,7 +2691,9 @@ static int replmd_replicated_apply_merge(struct replmd_replicated_request *ar)
                ldb_debug(ldb, LDB_DEBUG_TRACE, "replmd_replicated_request rename %s => %s\n",
                          ldb_dn_get_linearized(ar->search_msg->dn),
                          ldb_dn_get_linearized(msg->dn));
-               if (ldb_rename(ldb, ar->search_msg->dn, msg->dn) != LDB_SUCCESS) {
+               if (dsdb_module_rename(ar->module,
+                                      ar->search_msg->dn, msg->dn,
+                                      DSDB_FLAG_OWN_MODULE) != LDB_SUCCESS) {
                        ldb_debug(ldb, LDB_DEBUG_FATAL, "replmd_replicated_request rename %s => %s failed - %s\n",
                                  ldb_dn_get_linearized(ar->search_msg->dn),
                                  ldb_dn_get_linearized(msg->dn),
@@ -1347,21 +2737,28 @@ static int replmd_replicated_apply_merge(struct replmd_replicated_request *ar)
                bool found = false;
 
                for (j=0; j < ni; j++) {
-                       int cmp;
+                       bool cmp;
 
                        if (rmd->ctr.ctr1.array[i].attid != nmd.ctr.ctr1.array[j].attid) {
                                continue;
                        }
 
-                       cmp = replmd_replPropertyMetaData1_conflict_compare(&rmd->ctr.ctr1.array[i],
-                                                                           &nmd.ctr.ctr1.array[j]);
-                       if (cmp > 0) {
+                       cmp = replmd_replPropertyMetaData1_is_newer(&nmd.ctr.ctr1.array[j],
+                                                                   &rmd->ctr.ctr1.array[i]);
+                       if (cmp) {
                                /* replace the entry */
                                nmd.ctr.ctr1.array[j] = rmd->ctr.ctr1.array[i];
                                found = true;
                                break;
                        }
 
+                       if (rmd->ctr.ctr1.array[i].attid != DRSUAPI_ATTRIBUTE_instanceType) {
+                               DEBUG(1,("Discarding older DRS attribute update to %s on %s from %s\n",
+                                        msg->elements[i-removed_attrs].name,
+                                        ldb_dn_get_linearized(msg->dn),
+                                        GUID_string(ar, &rmd->ctr.ctr1.array[i].originating_invocation_id)));
+                       }
+
                        /* we don't want to apply this change so remove the attribute */
                        ldb_msg_remove_element(msg, &msg->elements[i-removed_attrs]);
                        removed_attrs++;
@@ -1407,13 +2804,13 @@ static int replmd_replicated_apply_merge(struct replmd_replicated_request *ar)
        ldb_debug(ldb, LDB_DEBUG_TRACE, "replmd_replicated_apply_merge[%u]: replace %u attributes\n",
                  ar->index_current, msg->num_elements);
 
-       ret = ldb_sequence_number(ldb, LDB_SEQ_NEXT, &seq_num);
+       ret = ldb_sequence_number(ldb, LDB_SEQ_NEXT, &ar->seq_num);
        if (ret != LDB_SUCCESS) {
                return replmd_replicated_request_error(ar, ret);
        }
 
        for (i=0; i<ni; i++) {
-               nmd.ctr.ctr1.array[i].local_usn = seq_num;
+               nmd.ctr.ctr1.array[i].local_usn = ar->seq_num;
        }
 
        /* create the meta data value */
@@ -1434,7 +2831,7 @@ static int replmd_replicated_apply_merge(struct replmd_replicated_request *ar)
        if (ret != LDB_SUCCESS) {
                return replmd_replicated_request_error(ar, ret);
        }
-       ret = samdb_msg_add_uint64(ldb, msg, msg, "uSNChanged", seq_num);
+       ret = samdb_msg_add_uint64(ldb, msg, msg, "uSNChanged", ar->seq_num);
        if (ret != LDB_SUCCESS) {
                return replmd_replicated_request_error(ar, ret);
        }
@@ -1450,11 +2847,6 @@ static int replmd_replicated_apply_merge(struct replmd_replicated_request *ar)
                msg->elements[i].flags = LDB_FLAG_MOD_REPLACE;
        }
 
-       ret = replmd_notify(ar->module, msg->dn, seq_num);
-       if (ret != LDB_SUCCESS) {
-               return replmd_replicated_request_error(ar, ret);
-       }
-
        if (DEBUGLVL(4)) {
                char *s = ldb_ldif_message_string(ldb, ar, LDB_CHANGETYPE_MODIFY, msg);
                DEBUG(4, ("DRS replication modify message:\n%s\n", s));
@@ -1467,7 +2859,7 @@ static int replmd_replicated_apply_merge(struct replmd_replicated_request *ar)
                                msg,
                                ar->controls,
                                ar,
-                               replmd_replicated_apply_merge_callback,
+                               replmd_op_callback,
                                ar->req);
        if (ret != LDB_SUCCESS) return replmd_replicated_request_error(ar, ret);
 
@@ -1524,6 +2916,7 @@ static int replmd_replicated_apply_next(struct replmd_replicated_request *ar)
        char *tmp_str;
        char *filter;
        struct ldb_request *search_req;
+       struct ldb_search_options_control *options;
 
        if (ar->index_current >= ar->objs->num_objects) {
                /* done with it, go to next stage */
@@ -1543,7 +2936,7 @@ static int replmd_replicated_apply_next(struct replmd_replicated_request *ar)
        ret = ldb_build_search_req(&search_req,
                                   ldb,
                                   ar,
-                                  ar->objs->partition_dn,
+                                  NULL,
                                   LDB_SCOPE_SUBTREE,
                                   filter,
                                   NULL,
@@ -1556,7 +2949,22 @@ static int replmd_replicated_apply_next(struct replmd_replicated_request *ar)
        if (ret != LDB_SUCCESS) {
                return ret;
        }
-       
+
+       /* we need to cope with cross-partition links, so search for
+          the GUID over all partitions */
+       options = talloc(search_req, struct ldb_search_options_control);
+       if (options == NULL) {
+               DEBUG(0, (__location__ ": out of memory\n"));
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+       options->search_options = LDB_SEARCH_OPTION_PHANTOM_ROOT;
+
+       ret = ldb_request_add_control(search_req,
+                                     LDB_CONTROL_SEARCH_OPTIONS_OID,
+                                     true, options);
+       if (ret != LDB_SUCCESS) {
+               return ret;
+       }
 
        if (ret != LDB_SUCCESS) return replmd_replicated_request_error(ar, ret);
 
@@ -1959,7 +3367,6 @@ static int replmd_extended_replicated_objects(struct ldb_module *module, struct
        struct replmd_replicated_request *ar;
        struct ldb_control **ctrls;
        int ret, i;
-       struct dsdb_control_current_partition *partition_ctrl;
        struct replmd_private *replmd_private = 
                talloc_get_type(ldb_module_get_private(module), struct replmd_private);
 
@@ -1983,6 +3390,8 @@ static int replmd_extended_replicated_objects(struct ldb_module *module, struct
        if (!ar)
                return LDB_ERR_OPERATIONS_ERROR;
 
+       /* Set the flags to have the replmd_op_callback run over the full set of objects */
+       ar->apply_mode = true;
        ar->objs = objs;
        ar->schema = dsdb_get_schema(ldb);
        if (!ar->schema) {
@@ -2005,27 +3414,6 @@ static int replmd_extended_replicated_objects(struct ldb_module *module, struct
                return ret;
        }
 
-       /*
-         add the DSDB_CONTROL_CURRENT_PARTITION_OID control. This
-         tells the partition module which partition this request is
-         directed at. That is important as the partition roots appear
-         twice in the directory, once as mount points in the top
-         level store, and once as the roots of each partition. The
-         replication code wants to operate on the root of the
-         partitions, not the top level mount points
-        */
-       partition_ctrl = talloc(req, struct dsdb_control_current_partition);
-       if (partition_ctrl == NULL) {
-               if (!partition_ctrl) return replmd_replicated_request_werror(ar, WERR_NOMEM);
-       }
-       partition_ctrl->version = DSDB_CONTROL_CURRENT_PARTITION_VERSION;
-       partition_ctrl->dn = objs->partition_dn;
-
-       ret = ldb_request_add_control(req, DSDB_CONTROL_CURRENT_PARTITION_OID, false, partition_ctrl);
-       if (ret != LDB_SUCCESS) {
-               return ret;
-       }
-
        ar->controls = req->controls;
        req->controls = ctrls;
 
@@ -2071,15 +3459,23 @@ static int replmd_process_linked_attribute(struct ldb_module *module,
 {                                         
        struct drsuapi_DsReplicaLinkedAttribute *la = la_entry->la;
        struct ldb_context *ldb = ldb_module_get_ctx(module);
-       struct drsuapi_DsReplicaObjectIdentifier3 target;
+       struct dsdb_schema *schema = dsdb_get_schema(ldb);
        struct ldb_message *msg;
-       struct ldb_message_element *ret_el;
        TALLOC_CTX *tmp_ctx = talloc_new(la_entry);
-       enum ndr_err_code ndr_err;
-       struct ldb_request *mod_req;
        int ret;
        const struct dsdb_attribute *attr;
-       struct ldb_dn *target_dn;
+       struct dsdb_dn *dsdb_dn;
+       uint64_t seq_num = 0;
+       struct ldb_message_element *old_el;
+       WERROR status;
+       time_t t = time(NULL);
+       struct ldb_result *res;
+       const char *attrs[2];
+       struct parsed_dn *pdn_list, *pdn;
+       struct GUID guid = GUID_zero();
+       NTSTATUS ntstatus;
+       bool active = (la->flags & DRSUAPI_DS_LINKED_ATTRIBUTE_FLAG_ACTIVE)?true:false;
+       const struct GUID *our_invocation_id;
 
 /*
 linked_attributes[0]:                                                     
@@ -2105,6 +3501,8 @@ linked_attributes[0]:
             originating_change_time  : Wed Sep  2 23:39:07 2009 EST            
             originating_invocation_id: 794640f3-18cf-40ee-a211-a93992b67a64    
             originating_usn          : 0x000000000001e19c (123292)             
+
+(for cases where the link is to a normal DN)
      &target: struct drsuapi_DsReplicaObjectIdentifier3                        
         __ndr_size               : 0x0000007e (126)                            
         __ndr_size_sid           : 0x0000001c (28)                             
@@ -2113,147 +3511,221 @@ linked_attributes[0]:
         __ndr_size_dn            : 0x00000022 (34)                                
         dn                       : 'CN=UOne,OU=TestOU,DC=vsofs8,DC=com'           
  */
-       if (DEBUGLVL(4)) {
-               NDR_PRINT_DEBUG(drsuapi_DsReplicaLinkedAttribute, la); 
-       }
        
-       /* decode the target of the link */
-       ndr_err = ndr_pull_struct_blob(la->value.blob, 
-                                      tmp_ctx, lp_iconv_convenience(ldb_get_opaque(ldb, "loadparm")), 
-                                      &target,
-                                      (ndr_pull_flags_fn_t)ndr_pull_drsuapi_DsReplicaObjectIdentifier3);
-       if (ndr_err != NDR_ERR_SUCCESS) {
-               DEBUG(0,("Unable to decode linked_attribute target\n"));
-               dump_data(4, la->value.blob->data, la->value.blob->length);                     
+       /* find the attribute being modified */
+       attr = dsdb_attribute_by_attributeID_id(schema, la->attid);
+       if (attr == NULL) {
+               DEBUG(0, (__location__ ": Unable to find attributeID 0x%x\n", la->attid));
                talloc_free(tmp_ctx);
                return LDB_ERR_OPERATIONS_ERROR;
        }
-       if (DEBUGLVL(4)) {
-               NDR_PRINT_DEBUG(drsuapi_DsReplicaObjectIdentifier3, &target);
-       }
 
-       /* construct a modify request for this attribute change */
-       msg = ldb_msg_new(tmp_ctx);
-       if (!msg) {
-               ldb_oom(ldb);
-               talloc_free(tmp_ctx);
-               return LDB_ERR_OPERATIONS_ERROR;
-       }
+       attrs[0] = attr->lDAPDisplayName;
+       attrs[1] = NULL;
 
-       ret = dsdb_find_dn_by_guid(ldb, tmp_ctx, 
-                                  GUID_string(tmp_ctx, &la->identifier->guid), &msg->dn);
+       /* get the existing message from the db for the object with
+          this GUID, returning attribute being modified. We will then
+          use this msg as the basis for a modify call */
+       ret = dsdb_module_search(module, tmp_ctx, &res, NULL, LDB_SCOPE_SUBTREE, attrs,
+                                DSDB_SEARCH_SEARCH_ALL_PARTITIONS |
+                                DSDB_SEARCH_SHOW_DELETED |
+                                DSDB_SEARCH_SHOW_DN_IN_STORAGE_FORMAT |
+                                DSDB_SEARCH_REVEAL_INTERNALS,
+                                "objectGUID=%s", GUID_string(tmp_ctx, &la->identifier->guid));
        if (ret != LDB_SUCCESS) {
                talloc_free(tmp_ctx);
                return ret;
        }
-
-       /* find the attribute being modified */
-       attr = dsdb_attribute_by_attributeID_id(dsdb_get_schema(ldb), la->attid);
-       if (attr == NULL) {
-               DEBUG(0, (__location__ ": Unable to find attributeID 0x%x\n", la->attid));
+       if (res->count != 1) {
+               ldb_asprintf_errstring(ldb, "DRS linked attribute for GUID %s - DN not found",
+                                      GUID_string(tmp_ctx, &la->identifier->guid));
                talloc_free(tmp_ctx);
-               return LDB_ERR_OPERATIONS_ERROR;
+               return LDB_ERR_NO_SUCH_OBJECT;
        }
+       msg = res->msgs[0];
 
-       if (la->flags & DRSUAPI_DS_LINKED_ATTRIBUTE_FLAG_ACTIVE) {
-               ret = ldb_msg_add_empty(msg, attr->lDAPDisplayName,
-                                       LDB_FLAG_MOD_ADD, &ret_el);
+       if (msg->num_elements == 0) {
+               ret = ldb_msg_add_empty(msg, attr->lDAPDisplayName, LDB_FLAG_MOD_REPLACE, &old_el);
+               if (ret != LDB_SUCCESS) {
+                       ldb_module_oom(module);
+                       talloc_free(tmp_ctx);
+                       return LDB_ERR_OPERATIONS_ERROR;
+               }
        } else {
-               ret = ldb_msg_add_empty(msg, attr->lDAPDisplayName,
-                                       LDB_FLAG_MOD_DELETE, &ret_el);
+               old_el = &msg->elements[0];
+               old_el->flags = LDB_FLAG_MOD_REPLACE;
        }
+
+       /* parse the existing links */
+       ret = get_parsed_dns(module, tmp_ctx, old_el, &pdn_list, attr->syntax->ldap_oid);
        if (ret != LDB_SUCCESS) {
                talloc_free(tmp_ctx);
                return ret;
        }
-       /* we allocate two entries here, in case we need a remove/add
-          pair */
-       ret_el->values = talloc_array(msg, struct ldb_val, 2);
-       if (!ret_el->values) {
-               ldb_oom(ldb);
+
+       /* get our invocationId */
+       our_invocation_id = samdb_ntds_invocation_id(ldb);
+       if (!our_invocation_id) {
+               ldb_debug_set(ldb, LDB_DEBUG_ERROR, __location__ ": unable to find invocationId\n");
                talloc_free(tmp_ctx);
                return LDB_ERR_OPERATIONS_ERROR;
        }
-       ret_el->num_values = 1;
 
-       ret = dsdb_find_dn_by_guid(ldb, tmp_ctx, GUID_string(tmp_ctx, &target.guid), &target_dn);
+       ret = replmd_check_upgrade_links(pdn_list, old_el->num_values, our_invocation_id);
        if (ret != LDB_SUCCESS) {
-               DEBUG(0,(__location__ ": Failed to map GUID %s to DN\n", GUID_string(tmp_ctx, &target.guid)));
                talloc_free(tmp_ctx);
+               return ret;
+       }
+
+       status = dsdb_dn_la_from_blob(ldb, attr, schema, tmp_ctx, la->value.blob, &dsdb_dn);
+       if (!W_ERROR_IS_OK(status)) {
+               ldb_asprintf_errstring(ldb, "Failed to parsed linked attribute blob for %s on %s - %s\n",
+                                      old_el->name, ldb_dn_get_linearized(msg->dn), win_errstr(status));
                return LDB_ERR_OPERATIONS_ERROR;
        }
 
-       ret_el->values[0].data = (uint8_t *)ldb_dn_get_extended_linearized(tmp_ctx, target_dn, 1);
-       ret_el->values[0].length = strlen((char *)ret_el->values[0].data);
+       ntstatus = dsdb_get_extended_dn_guid(dsdb_dn->dn, &guid, "GUID");
+       if (!NT_STATUS_IS_OK(ntstatus) && active) {
+               ldb_asprintf_errstring(ldb, "Failed to find GUID in linked attribute blob for %s on %s from %s",
+                                      old_el->name,
+                                      ldb_dn_get_linearized(dsdb_dn->dn),
+                                      ldb_dn_get_linearized(msg->dn));
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
 
-       ret = ldb_build_mod_req(&mod_req, ldb, tmp_ctx,
-                               msg,
-                               NULL,
-                               NULL, 
-                               ldb_op_default_callback,
-                               NULL);
+       /* re-resolve the DN by GUID, as the DRS server may give us an
+          old DN value */
+       ret = dsdb_module_dn_by_guid(module, dsdb_dn, &guid, &dsdb_dn->dn);
        if (ret != LDB_SUCCESS) {
+               ldb_asprintf_errstring(ldb, __location__ ": Failed to re-resolve GUID %s",
+                                      GUID_string(tmp_ctx, &guid));
                talloc_free(tmp_ctx);
                return ret;
        }
-       talloc_steal(mod_req, msg);
 
-       if (DEBUGLVL(4)) {
-               DEBUG(4,("Applying DRS linked attribute change:\n%s\n",
-                        ldb_ldif_message_string(ldb, tmp_ctx, LDB_CHANGETYPE_MODIFY, msg)));
-       }
+       /* see if this link already exists */
+       pdn = parsed_dn_find(pdn_list, old_el->num_values, &guid, dsdb_dn->dn);
+       if (pdn != NULL) {
+               /* see if this update is newer than what we have already */
+               struct GUID invocation_id = GUID_zero();
+               uint32_t version = 0;
+               NTTIME change_time = 0;
+               uint32_t rmd_flags = dsdb_dn_rmd_flags(pdn->dsdb_dn->dn);
+
+               dsdb_get_extended_dn_guid(pdn->dsdb_dn->dn, &invocation_id, "RMD_INVOCID");
+               dsdb_get_extended_dn_uint32(pdn->dsdb_dn->dn, &version, "RMD_VERSION");
+               dsdb_get_extended_dn_nttime(pdn->dsdb_dn->dn, &change_time, "RMD_CHANGETIME");
+
+               if (!replmd_update_is_newer(&invocation_id,
+                                           &la->meta_data.originating_invocation_id,
+                                           version,
+                                           la->meta_data.version,
+                                           change_time,
+                                           la->meta_data.originating_change_time)) {
+                       DEBUG(1,("Discarding older DRS linked attribute update to %s on %s from %s\n",
+                                old_el->name, ldb_dn_get_linearized(msg->dn),
+                                GUID_string(tmp_ctx, &la->meta_data.originating_invocation_id)));
+                       talloc_free(tmp_ctx);
+                       return LDB_SUCCESS;
+               }
 
-       /* Run the new request */
-       ret = ldb_next_request(module, mod_req);
+               /* get a seq_num for this change */
+               ret = ldb_sequence_number(ldb, LDB_SEQ_NEXT, &seq_num);
+               if (ret != LDB_SUCCESS) {
+                       talloc_free(tmp_ctx);
+                       return ret;
+               }
 
-       /* we need to wait for this to finish, as we are being called
-          from the synchronous end_transaction hook of this module */
-       if (ret == LDB_SUCCESS) {
-               ret = ldb_wait(mod_req->handle, LDB_WAIT_ALL);
-       }
+               if (!(rmd_flags & DSDB_RMD_FLAG_DELETED)) {
+                       /* remove the existing backlink */
+                       ret = replmd_add_backlink(module, schema, &la->identifier->guid, &guid, false, attr, false);
+                       if (ret != LDB_SUCCESS) {
+                               talloc_free(tmp_ctx);
+                               return ret;
+                       }
+               }
 
-       if (ret == LDB_ERR_ATTRIBUTE_OR_VALUE_EXISTS) {
-               /* the link destination exists, we need to update it
-                * by deleting the old one for the same DN then adding
-                * the new one */
-               msg->elements = talloc_realloc(msg, msg->elements,
-                                              struct ldb_message_element,
-                                              msg->num_elements+1);
-               if (msg->elements == NULL) {
-                       ldb_oom(ldb);
+               ret = replmd_update_la_val(tmp_ctx, pdn->v, dsdb_dn, pdn->dsdb_dn,
+                                          &la->meta_data.originating_invocation_id,
+                                          la->meta_data.originating_usn, seq_num,
+                                          la->meta_data.originating_change_time,
+                                          la->meta_data.version,
+                                          !active);
+               if (ret != LDB_SUCCESS) {
+                       talloc_free(tmp_ctx);
+                       return ret;
+               }
+
+               if (active) {
+                       /* add the new backlink */
+                       ret = replmd_add_backlink(module, schema, &la->identifier->guid, &guid, true, attr, false);
+                       if (ret != LDB_SUCCESS) {
+                               talloc_free(tmp_ctx);
+                               return ret;
+                       }
+               }
+       } else {
+               /* get a seq_num for this change */
+               ret = ldb_sequence_number(ldb, LDB_SEQ_NEXT, &seq_num);
+               if (ret != LDB_SUCCESS) {
                        talloc_free(tmp_ctx);
+                       return ret;
+               }
+
+               old_el->values = talloc_realloc(msg->elements, old_el->values,
+                                               struct ldb_val, old_el->num_values+1);
+               if (!old_el->values) {
+                       ldb_module_oom(module);
                        return LDB_ERR_OPERATIONS_ERROR;
                }
-               /* this relies on the backend matching the old entry
-                  only by the DN portion of the extended DN */
-               msg->elements[1] = msg->elements[0];
-               msg->elements[0].flags = LDB_FLAG_MOD_DELETE;
-               msg->num_elements++;
-
-               ret = ldb_build_mod_req(&mod_req, ldb, tmp_ctx,
-                                       msg,
-                                       NULL,
-                                       NULL, 
-                                       ldb_op_default_callback,
-                                       NULL);
+               old_el->num_values++;
+
+               ret = replmd_build_la_val(tmp_ctx, &old_el->values[old_el->num_values-1], dsdb_dn,
+                                         &la->meta_data.originating_invocation_id,
+                                         la->meta_data.originating_usn, seq_num,
+                                         la->meta_data.originating_change_time,
+                                         la->meta_data.version,
+                                         (la->flags & DRSUAPI_DS_LINKED_ATTRIBUTE_FLAG_ACTIVE)?false:true);
                if (ret != LDB_SUCCESS) {
                        talloc_free(tmp_ctx);
                        return ret;
                }
 
-               /* Run the new request */
-               ret = ldb_next_request(module, mod_req);
-               
-               if (ret == LDB_SUCCESS) {
-                       ret = ldb_wait(mod_req->handle, LDB_WAIT_ALL);
+               if (active) {
+                       ret = replmd_add_backlink(module, schema, &la->identifier->guid, &guid,
+                                                 true, attr, false);
+                       if (ret != LDB_SUCCESS) {
+                               talloc_free(tmp_ctx);
+                               return ret;
+                       }
                }
        }
 
+       /* we only change whenChanged and uSNChanged if the seq_num
+          has changed */
+       if (add_time_element(msg, "whenChanged", t) != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       if (add_uint64_element(msg, "uSNChanged", seq_num) != LDB_SUCCESS) {
+               talloc_free(tmp_ctx);
+               return LDB_ERR_OPERATIONS_ERROR;
+       }
+
+       ret = dsdb_check_single_valued_link(attr, old_el);
        if (ret != LDB_SUCCESS) {
-               ldb_debug(ldb, LDB_DEBUG_WARNING, "Failed to apply linked attribute change '%s' %s\n",
+               talloc_free(tmp_ctx);
+               return ret;
+       }
+
+       ret = dsdb_module_modify(module, msg, DSDB_MODIFY_RELAX);
+       if (ret != LDB_SUCCESS) {
+               ldb_debug(ldb, LDB_DEBUG_WARNING, "Failed to apply linked attribute change '%s'\n%s\n",
                          ldb_errstring(ldb),
                          ldb_ldif_message_string(ldb, tmp_ctx, LDB_CHANGETYPE_MODIFY, msg));
-               ret = LDB_SUCCESS;
+               talloc_free(tmp_ctx);
+               return ret;
        }
        
        talloc_free(tmp_ctx);
@@ -2281,15 +3753,16 @@ static int replmd_extended(struct ldb_module *module, struct ldb_request *req)
 static int replmd_start_transaction(struct ldb_module *module)
 {
        /* create our private structure for this transaction */
-       int i;
        struct replmd_private *replmd_private = talloc_get_type(ldb_module_get_private(module),
                                                                struct replmd_private);
-       talloc_free(replmd_private->la_ctx);
-       replmd_private->la_list = NULL;
-       replmd_private->la_ctx = NULL;
+       replmd_txn_cleanup(replmd_private);
 
-       for (i=0; i<replmd_private->num_ncs; i++) {
-               replmd_private->ncs[i].mod_usn = 0;
+       /* free any leftover mod_usn records from cancelled
+          transactions */
+       while (replmd_private->ncs) {
+               struct nc_entry *e = replmd_private->ncs;
+               DLIST_REMOVE(replmd_private->ncs, e);
+               talloc_free(e);
        }
 
        return ldb_next_start_trans(module);
@@ -2304,28 +3777,33 @@ static int replmd_prepare_commit(struct ldb_module *module)
        struct replmd_private *replmd_private = 
                talloc_get_type(ldb_module_get_private(module), struct replmd_private);
        struct la_entry *la, *prev;
+       struct la_backlink *bl;
        int ret;
 
        /* walk the list backwards, to do the first entry first, as we
         * added the entries with DLIST_ADD() which puts them at the
         * start of the list */
-       for (la = replmd_private->la_list; la && la->next; la=la->next) ;
-
-       for (; la; la=prev) {
-               prev = la->prev;
+       for (la = DLIST_TAIL(replmd_private->la_list); la; la=prev) {
+               prev = DLIST_PREV(la);
                DLIST_REMOVE(replmd_private->la_list, la);
                ret = replmd_process_linked_attribute(module, la);
                if (ret != LDB_SUCCESS) {
-                       talloc_free(replmd_private->la_ctx);
-                       replmd_private->la_list = NULL;
-                       replmd_private->la_ctx = NULL;
+                       replmd_txn_cleanup(replmd_private);
                        return ret;
                }
        }
 
-       talloc_free(replmd_private->la_ctx);
-       replmd_private->la_list = NULL;
-       replmd_private->la_ctx = NULL;
+       /* process our backlink list, creating and deleting backlinks
+          as necessary */
+       for (bl=replmd_private->la_backlinks; bl; bl=bl->next) {
+               ret = replmd_process_backlink(module, bl);
+               if (ret != LDB_SUCCESS) {
+                       replmd_txn_cleanup(replmd_private);
+                       return ret;
+               }
+       }
+
+       replmd_txn_cleanup(replmd_private);
 
        /* possibly change @REPLCHANGED */
        ret = replmd_notify_store(module);
@@ -2340,9 +3818,8 @@ static int replmd_del_transaction(struct ldb_module *module)
 {
        struct replmd_private *replmd_private = 
                talloc_get_type(ldb_module_get_private(module), struct replmd_private);
-       talloc_free(replmd_private->la_ctx);
-       replmd_private->la_list = NULL;
-       replmd_private->la_ctx = NULL;
+       replmd_txn_cleanup(replmd_private);
+
        return ldb_next_del_trans(module);
 }
 
@@ -2353,6 +3830,7 @@ _PUBLIC_ const struct ldb_module_ops ldb_repl_meta_data_module_ops = {
        .add               = replmd_add,
        .modify            = replmd_modify,
        .rename            = replmd_rename,
+       .del               = replmd_delete,
        .extended          = replmd_extended,
        .start_transaction = replmd_start_transaction,
        .prepare_commit    = replmd_prepare_commit,