ctdb-config: Switch tunable TDBMutexEnabled to a config option

Use the "database:tdb mutexes" option instead.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13589

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>

ctdb/common/tunable.c

@@ -145,7 +145,7 @@ static struct {
 		offsetof(struct ctdb_tunable_list, no_ip_host_on_all_disabled) },
 	{ "Samba3AvoidDeadlocks", 0, true,
 		offsetof(struct ctdb_tunable_list, samba3_hack) },
-	{ "TDBMutexEnabled", 1, false,
+	{ "TDBMutexEnabled", 1, true,
 		offsetof(struct ctdb_tunable_list, mutex_enabled) },
 	{ "LockProcessesPerDB", 200, false,
 		offsetof(struct ctdb_tunable_list, lock_processes_per_db) },

ctdb/database/database_conf.c

@@ -54,6 +54,22 @@ static bool check_static_string_change(const char *key,
 	return true;
 }
 
+static bool check_static_boolean_change(const char *key,
+					bool old_value,
+					bool new_value,
+					enum conf_update_mode mode)
+{
+	if (mode == CONF_MODE_RELOAD || CONF_MODE_API) {
+		if (old_value != new_value) {
+			D_WARNING("Ignoring update of [%s] -> %s\n",
+				  DATABASE_CONF_SECTION,
+				  key);
+		}
+	}
+
+	return true;
+}
+
 static bool database_conf_validate_lock_debug_script(const char *key,
 						     const char *old_script,
 						     const char *new_script,
@@ -141,4 +157,9 @@ void database_conf_init(struct conf_context *conf)
 			   DATABASE_CONF_LOCK_DEBUG_SCRIPT,
 			   NULL,
 			   database_conf_validate_lock_debug_script);
+	conf_define_boolean(conf,
+			    DATABASE_CONF_SECTION,
+			    DATABASE_CONF_TDB_MUTEXES,
+			    true,
+			    check_static_boolean_change);
 }

ctdb/database/database_conf.h

@@ -27,7 +27,8 @@
 #define DATABASE_CONF_VOLATILE_DB_DIR           "volatile database directory"
 #define DATABASE_CONF_PERSISTENT_DB_DIR         "persistent database directory"
 #define DATABASE_CONF_STATE_DB_DIR              "state database directory"
-#define DATABASE_CONF_LOCK_DEBUG_SCRIPT          "lock debug script"
+#define DATABASE_CONF_LOCK_DEBUG_SCRIPT         "lock debug script"
+#define DATABASE_CONF_TDB_MUTEXES               "tdb mutexes"
 
 void database_conf_init(struct conf_context *conf);
 

ctdb/doc/ctdb-tunables.7.xml

@@ -660,17 +660,6 @@ MonitorInterval=20
       </para>
     </refsect2>
 
-    <refsect2>
-      <title>TDBMutexEnabled</title>
-      <para>Default: 1</para>
-      <para>
-	This parameter enables TDB_MUTEX_LOCKING feature on volatile
-	databases if the robust mutexes are supported. This optimizes the
-	record locking using robust mutexes and is much more efficient
-	that using posix locks.
-      </para>
-    </refsect2>
-
     <refsect2>
       <title>TickleUpdateInterval</title>
       <para>Default: 20</para>

ctdb/doc/ctdb.1.xml

@@ -828,7 +828,6 @@ DBRecordCountWarn       = 100000
 DBRecordSizeWarn        = 10000000
 DBSizeWarn              = 100000000
 PullDBPreallocation     = 10485760
-TDBMutexEnabled         = 1
 LockProcessesPerDB      = 200
 RecBufferSizeLimit      = 1000000
 QueueBufferSize         = 1024

ctdb/doc/ctdb.conf.5.xml

@@ -304,6 +304,23 @@
 	</listitem>
       </varlistentry>
 
+      <varlistentry>
+	<term>tdb mutexes = true|false</term>
+	<listitem>
+	  <para>
+	    This parameter enables TDB_MUTEX_LOCKING feature on
+	    volatile databases if the robust mutexes are
+	    supported. This optimizes the record locking using robust
+	    mutexes and is much more efficient that using posix locks.
+	  </para>
+	  <para>
+	    If robust mutexes are unreliable on the platform being
+	    used then they can be disabled by setting this to
+	    <literal>false</literal>.
+	  </para>
+	</listitem>
+      </varlistentry>
+
       <varlistentry>
 	<term>lock debug script = <parameter>FILENAME</parameter></term>
 	<listitem>

ctdb/server/ctdb_config.c

@@ -73,6 +73,10 @@ static void setup_config_pointers(struct conf_context *conf)
 				   DATABASE_CONF_SECTION,
 				   DATABASE_CONF_LOCK_DEBUG_SCRIPT,
 				   &ctdb_config.lock_debug_script);
+	conf_assign_boolean_pointer(conf,
+				    DATABASE_CONF_SECTION,
+				    DATABASE_CONF_TDB_MUTEXES,
+				    &ctdb_config.tdb_mutexes);
 
 	/*
 	 * Event

ctdb/server/ctdb_config.h

@@ -33,6 +33,7 @@ struct ctdb_config {
 	const char *dbdir_persistent;
 	const char *dbdir_state;
 	const char *lock_debug_script;
+	bool tdb_mutexes;
 
 	/* Event */
 	const char *event_debug_script;

ctdb/server/ctdb_ltdb_server.c

@@ -41,6 +41,8 @@
 #include "common/common.h"
 #include "common/logging.h"
 
+#include "server/ctdb_config.h"
+
 #define PERSISTENT_HEALTH_TDB "persistent_health.tdb"
 
 /**
@@ -846,8 +848,9 @@ static int ctdb_local_attach(struct ctdb_context *ctdb, const char *db_name,
 						ctdb->db_directory,
 					   db_name, ctdb->pnn);
 
-	tdb_flags = ctdb_db_tdb_flags(db_flags, ctdb->valgrinding,
-				      ctdb->tunable.mutex_enabled);
+	tdb_flags = ctdb_db_tdb_flags(db_flags,
+				      ctdb->valgrinding,
+				      ctdb_config.tdb_mutexes);
 
 again:
 	ctdb_db->ltdb = tdb_wrap_open(ctdb_db, ctdb_db->db_path,

ctdb/tests/cunit/config_test_001.sh

@@ -40,6 +40,7 @@ ok <<EOF
 	# persistent database directory = ${database_persistent_dbdir}
 	# state database directory = ${database_state_dbdir}
 	# lock debug script = 
+	# tdb mutexes = true
 [event]
 	# debug script = 
 [legacy]

ctdb/tests/eventscripts/00.ctdb.setup.002.sh

@@ -8,12 +8,10 @@ setup
 
 setup_tunable_config <<EOF
 MonitorInterval=5
-TDBMutexEnabled=0
 EOF
 
 required_result 0 <<EOF
 Set MonitorInterval to 5
-Set TDBMutexEnabled to 0
 EOF
 
 simple_test

ctdb/tests/eventscripts/scripts/00.ctdb.sh

@@ -8,7 +8,6 @@ setup ()
 
 	export FAKE_CTDB_TUNABLES_OK="
 	       MonitorInterval
-	       TDBMutexEnabled
 	       DatabaseHashSize
 	       "
 	export FAKE_CTDB_TUNABLES_OBSOLETE="

ctdb/tests/tool/ctdb.listvars.001.sh

@@ -58,7 +58,6 @@ DBRecordCountWarn          = 100000
 DBRecordSizeWarn           = 10000000
 DBSizeWarn                 = 100000000
 PullDBPreallocation        = 10485760
-TDBMutexEnabled            = 1
 LockProcessesPerDB         = 200
 RecBufferSizeLimit         = 1000000
 QueueBufferSize            = 1024