use the prepare_commit op in the partition code

This makes multi-partition ldb's much safer

diff --git a/source4/dsdb/samdb/ldb_modules/partition.c b/source4/dsdb/samdb/ldb_modules/partition.c
index 71a1b8e9427d288a99933eb4e023d137a44770bc..3231f7ab0fc9265cfd293fc9fb3b63588852bcd8 100644 (file)
--- a/source4/dsdb/samdb/ldb_modules/partition.c
+++ b/source4/dsdb/samdb/ldb_modules/partition.c
@@ -73,11 +73,14 @@ static struct partition_context *partition_init_ctx(struct ldb_module *module, s
        return ac;
 }
 
-#define PARTITION_FIND_OP(module, op) do { \
-       struct ldb_context *ldbctx = module->ldb; \
+#define PARTITION_FIND_OP_NOERROR(module, op) do { \
         while (module && module->ops->op == NULL) module = module->next; \
+} while (0)
+
+#define PARTITION_FIND_OP(module, op) do { \
+       PARTITION_FIND_OP_NOERROR(module, op); \
         if (module == NULL) { \
-                ldb_asprintf_errstring(ldbctx, \
+                ldb_asprintf_errstring(module->ldb, \
                        "Unable to find backend operation for " #op ); \
                 return LDB_ERR_OPERATIONS_ERROR; \
         } \
@@ -654,7 +657,7 @@ static int partition_start_trans(struct ldb_module *module)
 /* end a transaction */
 static int partition_end_trans(struct ldb_module *module)
 {
-       int i, ret;
+       int i, ret, final_ret;
        struct partition_private_data *data = talloc_get_type(module->private_data, 
                                                              struct partition_private_data);
        ret = ldb_next_end_trans(module);
@@ -662,28 +665,60 @@ static int partition_end_trans(struct ldb_module *module)
                return ret;
        }
 
+       /* if the backend has a prepare_commit op then use that, to ensure
+          that all partitions are committed safely together */
+       for (i=0; data && data->partitions && data->partitions[i]; i++) {
+               struct ldb_module *next_end = data->partitions[i]->module;
+               struct ldb_module *next_prepare = data->partitions[i]->module;
+               struct ldb_module *next_del = data->partitions[i]->module;
+
+               PARTITION_FIND_OP_NOERROR(next_prepare, prepare_commit);
+               if (next_prepare == NULL) {
+                       continue;
+               }
+
+               PARTITION_FIND_OP(next_end, end_transaction);
+               PARTITION_FIND_OP(next_del, del_transaction);
+
+               if (next_end != next_prepare || next_del != next_end) {
+                       ldb_asprintf_errstring(module->ldb, "ERROR: Mismatch between prepare and commit ops in ldb module");
+                       return LDB_ERR_OPERATIONS_ERROR;
+               }
+               
+               ret = next_prepare->ops->prepare_commit(next_prepare);
+               if (ret != LDB_SUCCESS) {
+                       /* if one fails, cancel all but this one */
+                       int j;
+                       for (j=0; data->partitions[j]; j++) {
+                               if (j == i) continue;
+                               next_del = data->partitions[j]->module;
+                               PARTITION_FIND_OP(next_del, del_transaction);
+                               next_del->ops->del_transaction(next_del);
+                       }
+                       ldb_next_del_trans(module);
+                       return ret;
+               }
+       }
+
        /* Look at base DN */
        /* Figure out which partition it is under */
        /* Skip the lot if 'data' isn't here yet (initialistion) */
+       final_ret = LDB_SUCCESS;
+
        for (i=0; data && data->partitions && data->partitions[i]; i++) {
                struct ldb_module *next = data->partitions[i]->module;
                PARTITION_FIND_OP(next, end_transaction);
 
                ret = next->ops->end_transaction(next);
                if (ret != LDB_SUCCESS) {
-                       /* Back it out, if it fails on one */
-                       for (i--; i >= 0; i--) {
-                               next = data->partitions[i]->module;
-                               PARTITION_FIND_OP(next, del_transaction);
-
-                               next->ops->del_transaction(next);
-                       }
-                       ldb_next_del_trans(module);
-                       return ret;
+                       /* this should only be happening if we had a serious 
+                          OS or hardware error */
+                       ldb_asprintf_errstring(module->ldb, "ERROR: partition commit error");
+                       final_ret = ret;
                }
        }
 
-       return LDB_SUCCESS;
+       return final_ret;
 }
 
 /* delete a transaction */