Do not treat absense of gres.conf file as fatal error.

Do not treat the absence of a gres.conf file as a fatal error on systems
configured with GRES, but set GRES counts to zero. These counts can be
Counts can be altered by node_config_load() in the gres plugin.

NEWS

@@ -15,6 +15,8 @@ documents those changes that are of interest to users and admins.
     4.6 compiler.
  -- Fix for sview reservation tab when finding correct reservation.
  -- Fix for handling QOS limits per user on a reconfig of the slurmctld.
+ -- Do not treat the absence of a gres.conf file as a fatal error on systems
+    configured with GRES, but set GRES counts to zero.
 
 * Changes in SLURM 2.3.0-2
 ==========================

doc/man/man5/gres.conf.5

-.TH "gres.conf" "5" "September 2010" "gres.conf 2.2" "Slurm configuration file"
+.TH "gres.conf" "5" "September 2011" "gres.conf 2.3" "Slurm configuration file"
 .SH "NAME"
 gres.conf \- Slurm configuration file for generic resource management.
 
@@ -8,7 +8,8 @@ of generic resources on each compute node. Each node must contain a
 gres.conf file if generic resources are to be scheduled by SLURM.
 The file location can be modified at system build time using the
 DEFAULT_SLURM_CONF parameter. The file will always be located in the
-same directory as the \fBslurm.conf\fP file.
+same directory as the \fBslurm.conf\fP file. If generic resource counts are
+set by the gres plugin function node_config_load(), this file may be optional.
 .LP
 Parameter names are case insensitive.
 Any text following a "#" in the configuration file is treated

src/common/gres.c

@@ -765,9 +765,13 @@ extern int gres_plugin_node_config_devices_path(char **dev_path,
 
 	gres_plugin_init();
 	gres_conf_file = _get_gres_conf();
+	if (stat(gres_conf_file, &config_stat) < 0) {
+		error("can't stat gres.conf file %s: %m", gres_conf_file);
+		xfree(gres_conf_file);
+		return 0;
+	}
+
 	slurm_mutex_lock(&gres_context_lock);
-	if (stat(gres_conf_file, &config_stat) < 0)
-		fatal("can't stat gres.conf file %s: %m", gres_conf_file);
 	tbl = s_p_hashtbl_create(_gres_options);
 	if (s_p_parse_file(tbl, NULL, gres_conf_file, false) == SLURM_ERROR)
 		fatal("error opening/reading %s", gres_conf_file);
@@ -796,7 +800,32 @@ extern int gres_plugin_node_config_devices_path(char **dev_path,
 	return count;
 }
 
+/* No gres.conf file found.
+ * Initialize gres table with zero counts of all resources.
+ * Counts can be altered by node_config_load() in the gres plugin. */
+static int _no_gres_conf(uint32_t cpu_cnt)
+{
+	int i, rc = SLURM_SUCCESS;
+	gres_slurmd_conf_t *p;
 
+	slurm_mutex_lock(&gres_context_lock);
+	FREE_NULL_LIST(gres_conf_list);
+	gres_conf_list = list_create(_destroy_gres_slurmd_conf);
+	if (gres_conf_list == NULL)
+		fatal("list_create: malloc failure");
+	p = xmalloc(sizeof(gres_slurmd_conf_t *) * gres_context_cnt);
+	for (i = 0; ((i < gres_context_cnt) && (rc == SLURM_SUCCESS)); i++) {
+		p = xmalloc(sizeof(gres_slurmd_conf_t));
+		p->cpu_cnt	= cpu_cnt;
+		p->name		= xstrdup(gres_context[i].gres_name);
+		p->plugin_id	= gres_context[i].plugin_id;
+		list_append(gres_conf_list, p);
+		rc = (*(gres_context[i].ops.node_config_load))(gres_conf_list);
+	}
+	slurm_mutex_unlock(&gres_context_lock);
+
+	return rc;
+}
 
 /*
  * Load this node's configuration (how many resources it has, topology, etc.)
@@ -820,10 +849,15 @@ extern int gres_plugin_node_config_load(uint32_t cpu_cnt)
 		return SLURM_SUCCESS;
 
 	gres_conf_file = _get_gres_conf();
+	if (stat(gres_conf_file, &config_stat) < 0) {
+		error("can't stat gres.conf file %s, assuming zero resource "
+		      "counts", gres_conf_file);
+		xfree(gres_conf_file);
+		return _no_gres_conf(cpu_cnt);
+	}
+
 	slurm_mutex_lock(&gres_context_lock);
 	gres_cpu_cnt = cpu_cnt;
-	if (stat(gres_conf_file, &config_stat) < 0)
-		fatal("can't stat gres.conf file %s: %m", gres_conf_file);
 	tbl = s_p_hashtbl_create(_gres_options);
 	if (s_p_parse_file(tbl, NULL, gres_conf_file, false) == SLURM_ERROR)
 		fatal("error opening/reading %s", gres_conf_file);