dsdb: Do not create a transaction in partition_init()

This will allow us to lock the databases for read during all of the Samba init
hooks.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13379

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>

diff --git a/source4/dsdb/samdb/ldb_modules/partition_metadata.c b/source4/dsdb/samdb/ldb_modules/partition_metadata.c
index e3ad0d8c6c213e42acd4a5434163d91951bd7915..3e60393a2c9130cfb7ce77c6b54c475f109ea5b7 100644 (file)
--- a/source4/dsdb/samdb/ldb_modules/partition_metadata.c
+++ b/source4/dsdb/samdb/ldb_modules/partition_metadata.c
@@ -319,38 +319,6 @@ int partition_metadata_init(struct ldb_module *module)
                return ret;
        }
 
-       /*
-        * We need to fill in the sequence number from the DB, so we
-        * need to get a lock over all the databases.  We only read
-        * from the main partitions, but write to metadata so to avoid
-        * lock ordering we just get a transaction over the lot.
-        */
-       ret = partition_start_trans(module);
-       if (ret != LDB_SUCCESS) {
-               TALLOC_FREE(data->metadata);
-               return ret;
-       }
-
-       ret = partition_metadata_set_sequence_number(module);
-       if (ret != LDB_SUCCESS) {
-               TALLOC_FREE(data->metadata);
-               partition_del_trans(module);
-               return ret;
-       }
-
-       ret = partition_prepare_commit(module);
-       if (ret != LDB_SUCCESS) {
-               TALLOC_FREE(data->metadata);
-               partition_del_trans(module);
-               return ret;
-       }
-
-       ret = partition_end_trans(module);
-       if (ret != LDB_SUCCESS) {
-               /* Nothing much we can do */
-               TALLOC_FREE(data->metadata);
-       }
-
        return ret;
 }
 
@@ -370,6 +338,13 @@ int partition_metadata_sequence_number(struct ldb_module *module, uint64_t *valu
                return ret;
        }
 
+       /*
+        * This means we will give a 0 until the first write
+        * tranaction, which is actually pretty reasonable.
+        *
+        * All modern databases will have the metadata.tdb from
+        * the time of the first transaction in provision anyway.
+        */
        ret = partition_metadata_get_uint64(module,
                                            LDB_METADATA_SEQ_NUM,
                                            value,
@@ -410,6 +385,26 @@ int partition_metadata_sequence_number_increment(struct ldb_module *module, uint
                return ret;
        }
 
+       if (*value == 0) {
+               /*
+                * We are in a transaction now, so we can get the
+                * sequence number from the partitions.
+                */
+               ret = partition_metadata_set_sequence_number(module);
+               if (ret != LDB_SUCCESS) {
+                       TALLOC_FREE(data->metadata);
+                       partition_del_trans(module);
+                       return ret;
+               }
+
+               ret = partition_metadata_get_uint64(module,
+                                                   LDB_METADATA_SEQ_NUM,
+                                                   value, 0);
+               if (ret != LDB_SUCCESS) {
+                       return ret;
+               }
+       }
+
        (*value)++;
        ret = partition_metadata_set_uint64(module, LDB_METADATA_SEQ_NUM, *value, false);
        return ret;