s4-repl: we should only update uSNChanged when replication data changes

When changing non-replicated attributes we should not update the
uSNChanged attribute on the record, otherwise the DRS server will
think this record needs replicating.

1 files changed, 39 insertions, 29 deletions

diff --git a/source4/dsdb/samdb/ldb_modules/repl_meta_data.c b/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
index b9de04a684..5000c56d4e 100644
--- a/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
+++ b/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
@@ -280,7 +280,7 @@ static int replmd_add(struct ldb_module *module, struct ldb_request *req)
 	schema = dsdb_get_schema(ldb);
 	if (!schema) {
 		ldb_debug_set(ldb, LDB_DEBUG_FATAL,
-			      "replmd_modify: no dsdb_schema loaded");
+			      "replmd_add: no dsdb_schema loaded");
 		return LDB_ERR_CONSTRAINT_VIOLATION;
 	}
 
@@ -475,10 +475,9 @@ static int replmd_update_rpmd_element(struct ldb_context *ldb,
 				      struct ldb_message_element *el,
 				      struct replPropertyMetaDataBlob *omd,
 				      struct dsdb_schema *schema,
-				      uint64_t seq_num,
+				      uint64_t *seq_num,
 				      const struct GUID *our_invocation_id,
-				      NTTIME now,
-				      bool *modified)
+				      NTTIME now)
 {
 	int i;
 	const struct dsdb_attribute *a;
@@ -512,15 +511,25 @@ static int replmd_update_rpmd_element(struct ldb_context *ldb,
 		omd->ctr.ctr1.count++;
 	}
 
+	/* Get a new sequence number from the backend. We only do this
+	 * if we have a change that requires a new
+	 * replPropertyMetaData element 
+	 */
+	if (*seq_num == 0) {
+		int ret = ldb_sequence_number(ldb, LDB_SEQ_NEXT, seq_num);
+		if (ret != LDB_SUCCESS) {
+			return LDB_ERR_OPERATIONS_ERROR;
+		}
+	}
+
 	md1 = &omd->ctr.ctr1.array[i];
 	md1->version                   = 1;
 	md1->attid                     = a->attributeID_id;
 	md1->originating_change_time   = now;
 	md1->originating_invocation_id = *our_invocation_id;
-	md1->originating_usn           = seq_num;
-	md1->local_usn                 = seq_num;
+	md1->originating_usn           = *seq_num;
+	md1->local_usn                 = *seq_num;
 	
-	*modified = true;
 	return LDB_SUCCESS;
 }
 
@@ -530,13 +539,12 @@ static int replmd_update_rpmd_element(struct ldb_context *ldb,
  * client is based on this object 
  */
 static int replmd_update_rpmd(struct ldb_context *ldb, struct ldb_message *msg,
-			      uint64_t seq_num)
+			      uint64_t *seq_num)
 {
 	const struct ldb_val *omd_value;
 	enum ndr_err_code ndr_err;
 	struct replPropertyMetaDataBlob omd;
 	int i;
-	bool modified = false;
 	struct dsdb_schema *schema;
 	time_t t = time(NULL);
 	NTTIME now;
@@ -590,13 +598,17 @@ static int replmd_update_rpmd(struct ldb_context *ldb, struct ldb_message *msg,
 
 	for (i=0; i<msg->num_elements; i++) {
 		ret = replmd_update_rpmd_element(ldb, msg, &msg->elements[i], &omd, schema, seq_num, 
-						 our_invocation_id, now, &modified);
+						 our_invocation_id, now);
 		if (ret != LDB_SUCCESS) {
 			return ret;
 		}
 	}
 
-	if (modified) {
+	/*
+	 * replmd_update_rpmd_element has done an update if the
+	 * seq_num is set
+	 */
+	if (*seq_num != 0) {
 		struct ldb_val *md_value;
 		struct ldb_message_element *el;
 
@@ -640,7 +652,7 @@ static int replmd_modify(struct ldb_module *module, struct ldb_request *req)
 	struct ldb_message *msg;
 	int ret;
 	time_t t = time(NULL);
-	uint64_t seq_num;
+	uint64_t seq_num = 0;
 
 	/* do not manipulate our control entries */
 	if (ldb_dn_is_special(req->op.mod.message->dn)) {
@@ -683,27 +695,11 @@ static int replmd_modify(struct ldb_module *module, struct ldb_request *req)
 	 *   attribute was changed
 	 */
 
-	/* Get a sequence number from the backend */
-	ret = ldb_sequence_number(ldb, LDB_SEQ_NEXT, &seq_num);
-	if (ret != LDB_SUCCESS) {
-		return LDB_ERR_OPERATIONS_ERROR;
-	}
-
-	ret = replmd_update_rpmd(ldb, msg, seq_num);
+	ret = replmd_update_rpmd(ldb, msg, &seq_num);
 	if (ret != LDB_SUCCESS) {
 		return ret;
 	}
 
-	if (add_time_element(msg, "whenChanged", t) != LDB_SUCCESS) {
-		talloc_free(ac);
-		return LDB_ERR_OPERATIONS_ERROR;
-	}
-
-	if (add_uint64_element(msg, "uSNChanged", seq_num) != LDB_SUCCESS) {
-		talloc_free(ac);
-		return LDB_ERR_OPERATIONS_ERROR;
-	}
-
 	/* TODO:
 	 * - sort the attributes by attid with replmd_ldb_message_sort()
 	 * - replace the old object with the newly constructed one
@@ -719,6 +715,20 @@ static int replmd_modify(struct ldb_module *module, struct ldb_request *req)
 	}
 	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;
+		}
+
+		if (add_uint64_element(msg, "uSNChanged", seq_num) != LDB_SUCCESS) {
+			talloc_free(ac);
+			return LDB_ERR_OPERATIONS_ERROR;
+		}
+	}
+
 	/* go on with the call chain */
 	return ldb_next_request(module, down_req);
 }