s4-dsdb: don't change replPropertyMetaData if the value hasn't changed

When updating replPropertyMetaData, check if the value being stored is
the same as the current value, and skip the update if it is.

This is based on a patch by Fernando J V da Silva <fernandojvsilva@yahoo.com.br>

diff --git a/source4/dsdb/samdb/ldb_modules/repl_meta_data.c b/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
index 51611aca1d3e5ea8c7b26de729cd8882f931e571..b1abc7d8b3e7ef1500d60b1650701ed09d69561f 100644 (file)
--- a/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
+++ b/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
@@ -983,6 +983,7 @@ static int replmd_add(struct ldb_module *module, struct ldb_request *req)
 static int replmd_update_rpmd_element(struct ldb_context *ldb,
                                      struct ldb_message *msg,
                                      struct ldb_message_element *el,
+                                     struct ldb_message_element *old_el,
                                      struct replPropertyMetaDataBlob *omd,
                                      const struct dsdb_schema *schema,
                                      uint64_t *seq_num,
@@ -1004,6 +1005,11 @@ static int replmd_update_rpmd_element(struct ldb_context *ldb,
                return LDB_SUCCESS;
        }
 
+       /* if the attribute's value haven't changed then return LDB_SUCCESS     */
+       if (old_el != NULL && ldb_msg_element_compare(el, old_el) == 0) {
+               return LDB_SUCCESS;
+       }
+
        for (i=0; i<omd->ctr.ctr1.count; i++) {
                if (a->attributeID_id == omd->ctr.ctr1.array[i].attid) break;
        }
@@ -1073,7 +1079,7 @@ static int replmd_update_rpmd(struct ldb_module *module,
        NTTIME now;
        const struct GUID *our_invocation_id;
        int ret;
-       const char *attrs[] = { "replPropertyMetaData" , "objectClass", NULL };
+       const char *attrs[] = { "replPropertyMetaData", "*", NULL };
        struct ldb_result *res;
        struct ldb_context *ldb;
        struct ldb_message_element *objectclass_el;
@@ -1091,8 +1097,16 @@ static int replmd_update_rpmd(struct ldb_module *module,
 
        unix_to_nt_time(&now, t);
 
-       /* search for the existing replPropertyMetaDataBlob */
-       ret = dsdb_search_dn_with_deleted(ldb, msg, &res, msg->dn, attrs);
+       /* search for the existing replPropertyMetaDataBlob. We need
+        * to use REVEAL and ask for DNs in storage format to support
+        * the check for values being the same in
+        * replmd_update_rpmd_element()
+        */
+       ret = dsdb_module_search_dn(module, msg, &res, msg->dn, attrs,
+                                   DSDB_SEARCH_SHOW_DELETED |
+                                   DSDB_SEARCH_SHOW_EXTENDED_DN |
+                                   DSDB_SEARCH_SHOW_DN_IN_STORAGE_FORMAT |
+                                   DSDB_SEARCH_REVEAL_INTERNALS);
        if (ret != LDB_SUCCESS || res->count != 1) {
                DEBUG(0,(__location__ ": Object %s failed to find replPropertyMetaData\n",
                         ldb_dn_get_linearized(msg->dn)));
@@ -1136,7 +1150,9 @@ static int replmd_update_rpmd(struct ldb_module *module,
        }
 
        for (i=0; i<msg->num_elements; i++) {
-               ret = replmd_update_rpmd_element(ldb, msg, &msg->elements[i], &omd, schema, seq_num,
+               struct ldb_message_element *old_el;
+               old_el = ldb_msg_find_element(res->msgs[0], msg->elements[i].name);
+               ret = replmd_update_rpmd_element(ldb, msg, &msg->elements[i], old_el, &omd, schema, seq_num,
                                                 our_invocation_id, now);
                if (ret != LDB_SUCCESS) {
                        return ret;