Revert to previous behavior:

always use DB_AUTO_COMMIT when opening a database, don't make it
  dependent on an in-progress transaction

  use mutex instead of DB lock for db access.

servers/slapd/back-bdb/back-bdb.h

@@ -141,6 +141,7 @@ struct bdb_info {
 
 	int			bi_ndatabases;
 	struct bdb_db_info **bi_databases;
+	ldap_pvt_thread_mutex_t	bi_database_mutex;
 	int		bi_db_opflags;	/* db-specific flags */
 
 	slap_mask_t	bi_defaultmask;
@@ -182,7 +183,7 @@ struct bdb_op_info {
 	int		boi_acl_cache;
 };
 
-#define	DB_OPEN(db, txn, file, name, type, flags, mode) \
+#define	DB_OPEN(db, file, name, type, flags, mode) \
 	(db)->open(db, file, name, type, flags, mode)
 
 #if DB_VERSION_MAJOR < 4
@@ -213,8 +214,8 @@ struct bdb_op_info {
 /* BDB 4.1.17 adds txn arg to db->open */
 #if DB_VERSION_MINOR > 1 || DB_VERSION_PATCH >= 17
 #undef DB_OPEN
-#define	DB_OPEN(db, txn, file, name, type, flags, mode) \
+#define	DB_OPEN(db, file, name, type, flags, mode) \
-	(db)->open(db, txn, file, name, type, flags, mode)
+	(db)->open(db, NULL, file, name, type, (flags)|DB_AUTO_COMMIT, mode)
 #endif
 
 #endif

servers/slapd/back-bdb/dbcache.c

@@ -46,19 +46,14 @@ bdb_db_hash(
 int
 bdb_db_cache(
 	Backend	*be,
-	DB_TXN *tid,
 	const char *name,
 	DB **dbout )
 {
 	int i;
 	int rc;
-	int flags;
 	struct bdb_info *bdb = (struct bdb_info *) be->be_private;
 	struct bdb_db_info *db;
 	char *file;
-	DBT lockobj;
-	DB_LOCK lock;
-	u_int32_t locker = 0;
 
 	*dbout = NULL;
 
@@ -69,33 +64,19 @@ bdb_db_cache(
 		}
 	}
 
-	lockobj.data = "bdb_db_cache";
+	ldap_pvt_thread_mutex_lock( &bdb->bi_database_mutex );
-	lockobj.size = sizeof("bdb_db_cache");
-
-	if (tid) {
-		locker = TXN_ID( tid );
-	} else {
-#ifdef BDB_REUSE_LOCKERS
-#define	op	NULL	/* implicit arg in LOCK_ID */
-#endif
-		rc = LOCK_ID( bdb->bi_dbenv, &locker );
-		if (rc) return rc;
-	}
-	rc = LOCK_GET( bdb->bi_dbenv, locker, 0, &lockobj,
-		DB_LOCK_WRITE, &lock );
-	if (rc) return rc;
 
 	/* check again! may have been added by another thread */
 	for( i=BDB_NDB; i < bdb->bi_ndatabases; i++ ) {
 		if( !strcmp( bdb->bi_databases[i]->bdi_name, name) ) {
 			*dbout = bdb->bi_databases[i]->bdi_db;
-			LOCK_PUT( bdb->bi_dbenv, &lock);
+			ldap_pvt_thread_mutex_unlock( &bdb->bi_database_mutex );
 			return 0;
 		}
 	}
 
 	if( i >= BDB_INDICES ) {
-		LOCK_PUT( bdb->bi_dbenv, &lock);
+		ldap_pvt_thread_mutex_unlock( &bdb->bi_database_mutex );
 		return -1;
 	}
 
@@ -114,7 +95,7 @@ bdb_db_cache(
 			"bdb_db_cache: db_create(%s) failed: %s (%d)\n",
 			bdb->bi_dbenv_home, db_strerror(rc), rc );
 #endif
-		LOCK_PUT( bdb->bi_dbenv, &lock);
+		ldap_pvt_thread_mutex_unlock( &bdb->bi_database_mutex );
 		return rc;
 	}
 
@@ -129,11 +110,9 @@ bdb_db_cache(
 #ifdef HAVE_EBCDIC
 	__atoe( file );
 #endif
-	flags = bdb->bi_db_opflags | DB_CREATE | DB_THREAD;
+	rc = DB_OPEN( db->bdi_db,
-	if ( !tid ) flags |= DB_AUTO_COMMIT;
-	rc = DB_OPEN( db->bdi_db, tid,
 		file, NULL /* name */,
-		DB_HASH, flags,
+		DB_HASH, bdb->bi_db_opflags | DB_CREATE | DB_THREAD,
 		bdb->bi_dbenv_mode );
 
 	ch_free( file );
@@ -148,7 +127,7 @@ bdb_db_cache(
 			"bdb_db_cache: db_open(%s) failed: %s (%d)\n",
 			name, db_strerror(rc), rc );
 #endif
-		LOCK_PUT( bdb->bi_dbenv, &lock);
+		ldap_pvt_thread_mutex_unlock( &bdb->bi_database_mutex );
 		return rc;
 	}
 
@@ -157,6 +136,6 @@ bdb_db_cache(
 
 	*dbout = db->bdi_db;
 
-	LOCK_PUT( bdb->bi_dbenv, &lock );
+	ldap_pvt_thread_mutex_unlock( &bdb->bi_database_mutex );
 	return 0;
 }

servers/slapd/back-bdb/index.c

@@ -97,7 +97,7 @@ int bdb_index_param(
 		return LDAP_INAPPROPRIATE_MATCHING;
 	}
 
-	rc = bdb_db_cache( be, NULL, prefixp->bv_val, &db );
+	rc = bdb_db_cache( be, prefixp->bv_val, &db );
 
 	if( rc != LDAP_SUCCESS ) {
 		return rc;
@@ -159,7 +159,7 @@ static int indexer(
 
 	assert( mask );
 
-	rc = bdb_db_cache( op->o_bd, txn, atname->bv_val, &db );
+	rc = bdb_db_cache( op->o_bd, atname->bv_val, &db );
 	
 	if ( rc != LDAP_SUCCESS ) {
 #ifdef NEW_LOGGING

servers/slapd/back-bdb/init.c

@@ -93,6 +93,7 @@ bdb_db_init( BackendDB *be )
 
 	LDAP_LIST_INIT (&bdb->bi_psearch_list);
 
+	ldap_pvt_thread_mutex_init( &bdb->bi_database_mutex );
 	ldap_pvt_thread_mutex_init( &bdb->bi_lastid_mutex );
 	ldap_pvt_thread_mutex_init( &bdb->bi_cache.lru_mutex );
 	ldap_pvt_thread_mutex_init( &bdb->bi_cache.c_dntree.bei_kids_mutex );
@@ -397,14 +398,14 @@ bdb_db_open( BackendDB *be )
 #ifdef HAVE_EBCDIC
 		strcpy( path, bdbi_databases[i].file );
 		__atoe( path );
-		rc = DB_OPEN( db->bdi_db, NULL,
+		rc = DB_OPEN( db->bdi_db,
 			path,
 		/*	bdbi_databases[i].name, */ NULL,
 			bdbi_databases[i].type,
 			bdbi_databases[i].flags | flags | DB_AUTO_COMMIT,
 			bdb->bi_dbenv_mode );
 #else
-		rc = DB_OPEN( db->bdi_db, NULL,
+		rc = DB_OPEN( db->bdi_db,
 			bdbi_databases[i].file,
 		/*	bdbi_databases[i].name, */ NULL,
 			bdbi_databases[i].type,
@@ -539,6 +540,7 @@ bdb_db_destroy( BackendDB *be )
 	ldap_pvt_thread_mutex_destroy( &bdb->bi_cache.lru_mutex );
 	ldap_pvt_thread_mutex_destroy( &bdb->bi_cache.c_dntree.bei_kids_mutex );
 	ldap_pvt_thread_mutex_destroy( &bdb->bi_lastid_mutex );
+	ldap_pvt_thread_mutex_destroy( &bdb->bi_database_mutex );
 #ifdef SLAP_IDL_CACHE
 	if ( bdb->bi_idl_cache_max_size ) {
 		ldap_pvt_thread_rdwr_destroy( &bdb->bi_idl_tree_rwlock );

servers/slapd/back-bdb/proto-bdb.h

@@ -55,7 +55,6 @@ int bdb_get_commit_csn LDAP_P(( Operation *op, SlapReply *rs,
 int
 bdb_db_cache(
     Backend	*be,
-    DB_TXN *tid,
     const char *name,
 	DB **db );