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32 results

cache.h

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  • config.c 21.36 KiB
    /******************************************************************************
    *******************************************************************************
    **
    **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
    **  Copyright (C) 2004-2011 Red Hat, Inc.  All rights reserved.
    **
    **  This copyrighted material is made available to anyone wishing to use,
    **  modify, copy, or redistribute it subject to the terms and conditions
    **  of the GNU General Public License v.2.
    **
    *******************************************************************************
    ******************************************************************************/
    
    #include <linux/kernel.h>
    #include <linux/module.h>
    #include <linux/configfs.h>
    #include <linux/slab.h>
    #include <linux/in.h>
    #include <linux/in6.h>
    #include <linux/dlmconstants.h>
    #include <net/ipv6.h>
    #include <net/sock.h>
    
    #include "config.h"
    #include "lowcomms.h"
    
    /*
     * /config/dlm/<cluster>/spaces/<space>/nodes/<node>/nodeid
     * /config/dlm/<cluster>/spaces/<space>/nodes/<node>/weight
     * /config/dlm/<cluster>/comms/<comm>/nodeid
     * /config/dlm/<cluster>/comms/<comm>/local
     * /config/dlm/<cluster>/comms/<comm>/addr      (write only)
     * /config/dlm/<cluster>/comms/<comm>/addr_list (read only)
     * The <cluster> level is useless, but I haven't figured out how to avoid it.
     */
    
    static struct config_group *space_list;
    static struct config_group *comm_list;
    static struct dlm_comm *local_comm;
    static uint32_t dlm_comm_count;
    
    struct dlm_clusters;
    struct dlm_cluster;
    struct dlm_spaces;
    struct dlm_space;
    struct dlm_comms;
    struct dlm_comm;
    struct dlm_nodes;
    struct dlm_node;
    
    static struct config_group *make_cluster(struct config_group *, const char *);
    static void drop_cluster(struct config_group *, struct config_item *);
    static void release_cluster(struct config_item *);
    static struct config_group *make_space(struct config_group *, const char *);
    static void drop_space(struct config_group *, struct config_item *);
    static void release_space(struct config_item *);
    static struct config_item *make_comm(struct config_group *, const char *);
    static void drop_comm(struct config_group *, struct config_item *);
    static void release_comm(struct config_item *);
    static struct config_item *make_node(struct config_group *, const char *);
    static void drop_node(struct config_group *, struct config_item *);
    static void release_node(struct config_item *);
    
    static struct configfs_attribute *comm_attrs[];
    static struct configfs_attribute *node_attrs[];
    
    struct dlm_cluster {
    	struct config_group group;
    	unsigned int cl_tcp_port;
    	unsigned int cl_buffer_size;
    	unsigned int cl_rsbtbl_size;
    	unsigned int cl_recover_timer;
    	unsigned int cl_toss_secs;
    	unsigned int cl_scan_secs;
    	unsigned int cl_log_debug;
    	unsigned int cl_protocol;
    	unsigned int cl_timewarn_cs;
    	unsigned int cl_waitwarn_us;
    	unsigned int cl_new_rsb_count;
    	unsigned int cl_recover_callbacks;
    	char cl_cluster_name[DLM_LOCKSPACE_LEN];
    };
    
    static struct dlm_cluster *config_item_to_cluster(struct config_item *i)
    {
    	return i ? container_of(to_config_group(i), struct dlm_cluster, group) :
    		   NULL;
    }
    
    enum {
    	CLUSTER_ATTR_TCP_PORT = 0,
    	CLUSTER_ATTR_BUFFER_SIZE,
    	CLUSTER_ATTR_RSBTBL_SIZE,
    	CLUSTER_ATTR_RECOVER_TIMER,
    	CLUSTER_ATTR_TOSS_SECS,
    	CLUSTER_ATTR_SCAN_SECS,
    	CLUSTER_ATTR_LOG_DEBUG,
    	CLUSTER_ATTR_PROTOCOL,
    	CLUSTER_ATTR_TIMEWARN_CS,
    	CLUSTER_ATTR_WAITWARN_US,
    	CLUSTER_ATTR_NEW_RSB_COUNT,
    	CLUSTER_ATTR_RECOVER_CALLBACKS,
    	CLUSTER_ATTR_CLUSTER_NAME,
    };
    
    static ssize_t cluster_cluster_name_show(struct config_item *item, char *buf)
    {
    	struct dlm_cluster *cl = config_item_to_cluster(item);
    	return sprintf(buf, "%s\n", cl->cl_cluster_name);
    }
    
    static ssize_t cluster_cluster_name_store(struct config_item *item,
    					  const char *buf, size_t len)
    {
    	struct dlm_cluster *cl = config_item_to_cluster(item);
    
    	strlcpy(dlm_config.ci_cluster_name, buf,
    				sizeof(dlm_config.ci_cluster_name));
    	strlcpy(cl->cl_cluster_name, buf, sizeof(cl->cl_cluster_name));
    	return len;
    }
    
    CONFIGFS_ATTR(cluster_, cluster_name);
    
    static ssize_t cluster_set(struct dlm_cluster *cl, unsigned int *cl_field,
    			   int *info_field, int check_zero,
    			   const char *buf, size_t len)
    {
    	unsigned int x;
    	int rc;
    
    	if (!capable(CAP_SYS_ADMIN))
    		return -EPERM;
    	rc = kstrtouint(buf, 0, &x);
    	if (rc)
    		return rc;
    
    	if (check_zero && !x)
    		return -EINVAL;
    
    	*cl_field = x;
    	*info_field = x;
    
    	return len;
    }
    
    #define CLUSTER_ATTR(name, check_zero)                                        \
    static ssize_t cluster_##name##_store(struct config_item *item, \
    		const char *buf, size_t len) \
    {                                                                             \
    	struct dlm_cluster *cl = config_item_to_cluster(item);		      \
    	return cluster_set(cl, &cl->cl_##name, &dlm_config.ci_##name,         \
    			   check_zero, buf, len);                             \
    }                                                                             \
    static ssize_t cluster_##name##_show(struct config_item *item, char *buf)     \
    {                                                                             \
    	struct dlm_cluster *cl = config_item_to_cluster(item);		      \
    	return snprintf(buf, PAGE_SIZE, "%u\n", cl->cl_##name);               \
    }                                                                             \
    CONFIGFS_ATTR(cluster_, name);
    
    CLUSTER_ATTR(tcp_port, 1);
    CLUSTER_ATTR(buffer_size, 1);
    CLUSTER_ATTR(rsbtbl_size, 1);
    CLUSTER_ATTR(recover_timer, 1);
    CLUSTER_ATTR(toss_secs, 1);
    CLUSTER_ATTR(scan_secs, 1);
    CLUSTER_ATTR(log_debug, 0);
    CLUSTER_ATTR(protocol, 0);
    CLUSTER_ATTR(timewarn_cs, 1);
    CLUSTER_ATTR(waitwarn_us, 0);
    CLUSTER_ATTR(new_rsb_count, 0);
    CLUSTER_ATTR(recover_callbacks, 0);
    
    static struct configfs_attribute *cluster_attrs[] = {
    	[CLUSTER_ATTR_TCP_PORT] = &cluster_attr_tcp_port,
    	[CLUSTER_ATTR_BUFFER_SIZE] = &cluster_attr_buffer_size,
    	[CLUSTER_ATTR_RSBTBL_SIZE] = &cluster_attr_rsbtbl_size,
    	[CLUSTER_ATTR_RECOVER_TIMER] = &cluster_attr_recover_timer,
    	[CLUSTER_ATTR_TOSS_SECS] = &cluster_attr_toss_secs,
    	[CLUSTER_ATTR_SCAN_SECS] = &cluster_attr_scan_secs,
    	[CLUSTER_ATTR_LOG_DEBUG] = &cluster_attr_log_debug,
    	[CLUSTER_ATTR_PROTOCOL] = &cluster_attr_protocol,
    	[CLUSTER_ATTR_TIMEWARN_CS] = &cluster_attr_timewarn_cs,
    	[CLUSTER_ATTR_WAITWARN_US] = &cluster_attr_waitwarn_us,
    	[CLUSTER_ATTR_NEW_RSB_COUNT] = &cluster_attr_new_rsb_count,
    	[CLUSTER_ATTR_RECOVER_CALLBACKS] = &cluster_attr_recover_callbacks,
    	[CLUSTER_ATTR_CLUSTER_NAME] = &cluster_attr_cluster_name,
    	NULL,
    };
    
    enum {
    	COMM_ATTR_NODEID = 0,
    	COMM_ATTR_LOCAL,
    	COMM_ATTR_ADDR,
    	COMM_ATTR_ADDR_LIST,
    };
    
    enum {
    	NODE_ATTR_NODEID = 0,
    	NODE_ATTR_WEIGHT,
    };
    
    struct dlm_clusters {
    	struct configfs_subsystem subsys;
    };
    
    struct dlm_spaces {
    	struct config_group ss_group;
    };
    
    struct dlm_space {
    	struct config_group group;
    	struct list_head members;
    	struct mutex members_lock;
    	int members_count;
    };
    
    struct dlm_comms {
    	struct config_group cs_group;
    };
    
    struct dlm_comm {
    	struct config_item item;
    	int seq;
    	int nodeid;
    	int local;
    	int addr_count;
    	struct sockaddr_storage *addr[DLM_MAX_ADDR_COUNT];
    };
    
    struct dlm_nodes {
    	struct config_group ns_group;
    };
    
    struct dlm_node {
    	struct config_item item;
    	struct list_head list; /* space->members */
    	int nodeid;
    	int weight;
    	int new;
    	int comm_seq; /* copy of cm->seq when nd->nodeid is set */
    };
    
    static struct configfs_group_operations clusters_ops = {
    	.make_group = make_cluster,
    	.drop_item = drop_cluster,
    };
    
    static struct configfs_item_operations cluster_ops = {
    	.release = release_cluster,
    };
    
    static struct configfs_group_operations spaces_ops = {
    	.make_group = make_space,
    	.drop_item = drop_space,
    };
    
    static struct configfs_item_operations space_ops = {
    	.release = release_space,
    };
    
    static struct configfs_group_operations comms_ops = {
    	.make_item = make_comm,
    	.drop_item = drop_comm,
    };
    
    static struct configfs_item_operations comm_ops = {
    	.release = release_comm,
    };
    
    static struct configfs_group_operations nodes_ops = {
    	.make_item = make_node,
    	.drop_item = drop_node,
    };
    
    static struct configfs_item_operations node_ops = {
    	.release = release_node,
    };
    
    static struct config_item_type clusters_type = {
    	.ct_group_ops = &clusters_ops,
    	.ct_owner = THIS_MODULE,
    };
    
    static struct config_item_type cluster_type = {
    	.ct_item_ops = &cluster_ops,
    	.ct_attrs = cluster_attrs,
    	.ct_owner = THIS_MODULE,
    };
    
    static struct config_item_type spaces_type = {
    	.ct_group_ops = &spaces_ops,
    	.ct_owner = THIS_MODULE,
    };
    
    static struct config_item_type space_type = {
    	.ct_item_ops = &space_ops,
    	.ct_owner = THIS_MODULE,
    };
    
    static struct config_item_type comms_type = {
    	.ct_group_ops = &comms_ops,
    	.ct_owner = THIS_MODULE,
    };
    
    static struct config_item_type comm_type = {
    	.ct_item_ops = &comm_ops,
    	.ct_attrs = comm_attrs,
    	.ct_owner = THIS_MODULE,
    };
    
    static struct config_item_type nodes_type = {
    	.ct_group_ops = &nodes_ops,
    	.ct_owner = THIS_MODULE,
    };
    
    static struct config_item_type node_type = {
    	.ct_item_ops = &node_ops,
    	.ct_attrs = node_attrs,
    	.ct_owner = THIS_MODULE,
    };
    
    static struct dlm_space *config_item_to_space(struct config_item *i)
    {
    	return i ? container_of(to_config_group(i), struct dlm_space, group) :
    		   NULL;
    }
    
    static struct dlm_comm *config_item_to_comm(struct config_item *i)
    {
    	return i ? container_of(i, struct dlm_comm, item) : NULL;
    }
    
    static struct dlm_node *config_item_to_node(struct config_item *i)
    {
    	return i ? container_of(i, struct dlm_node, item) : NULL;
    }
    
    static struct config_group *make_cluster(struct config_group *g,
    					 const char *name)
    {
    	struct dlm_cluster *cl = NULL;
    	struct dlm_spaces *sps = NULL;
    	struct dlm_comms *cms = NULL;
    
    	cl = kzalloc(sizeof(struct dlm_cluster), GFP_NOFS);
    	sps = kzalloc(sizeof(struct dlm_spaces), GFP_NOFS);
    	cms = kzalloc(sizeof(struct dlm_comms), GFP_NOFS);
    
    	if (!cl || !sps || !cms)
    		goto fail;
    
    	config_group_init_type_name(&cl->group, name, &cluster_type);
    	config_group_init_type_name(&sps->ss_group, "spaces", &spaces_type);
    	config_group_init_type_name(&cms->cs_group, "comms", &comms_type);
    
    	configfs_add_default_group(&sps->ss_group, &cl->group);
    	configfs_add_default_group(&cms->cs_group, &cl->group);
    
    	cl->cl_tcp_port = dlm_config.ci_tcp_port;
    	cl->cl_buffer_size = dlm_config.ci_buffer_size;
    	cl->cl_rsbtbl_size = dlm_config.ci_rsbtbl_size;
    	cl->cl_recover_timer = dlm_config.ci_recover_timer;
    	cl->cl_toss_secs = dlm_config.ci_toss_secs;
    	cl->cl_scan_secs = dlm_config.ci_scan_secs;
    	cl->cl_log_debug = dlm_config.ci_log_debug;
    	cl->cl_protocol = dlm_config.ci_protocol;
    	cl->cl_timewarn_cs = dlm_config.ci_timewarn_cs;
    	cl->cl_waitwarn_us = dlm_config.ci_waitwarn_us;
    	cl->cl_new_rsb_count = dlm_config.ci_new_rsb_count;
    	cl->cl_recover_callbacks = dlm_config.ci_recover_callbacks;
    	memcpy(cl->cl_cluster_name, dlm_config.ci_cluster_name,
    	       DLM_LOCKSPACE_LEN);
    
    	space_list = &sps->ss_group;
    	comm_list = &cms->cs_group;
    	return &cl->group;
    
     fail:
    	kfree(cl);
    	kfree(sps);
    	kfree(cms);
    	return ERR_PTR(-ENOMEM);
    }
    
    static void drop_cluster(struct config_group *g, struct config_item *i)
    {
    	struct dlm_cluster *cl = config_item_to_cluster(i);
    
    	configfs_remove_default_groups(&cl->group);
    
    	space_list = NULL;
    	comm_list = NULL;
    
    	config_item_put(i);
    }
    
    static void release_cluster(struct config_item *i)
    {
    	struct dlm_cluster *cl = config_item_to_cluster(i);
    	kfree(cl);
    }
    
    static struct config_group *make_space(struct config_group *g, const char *name)
    {
    	struct dlm_space *sp = NULL;
    	struct dlm_nodes *nds = NULL;
    
    	sp = kzalloc(sizeof(struct dlm_space), GFP_NOFS);
    	nds = kzalloc(sizeof(struct dlm_nodes), GFP_NOFS);
    
    	if (!sp || !nds)
    		goto fail;
    
    	config_group_init_type_name(&sp->group, name, &space_type);
    
    	config_group_init_type_name(&nds->ns_group, "nodes", &nodes_type);
    	configfs_add_default_group(&nds->ns_group, &sp->group);
    
    	INIT_LIST_HEAD(&sp->members);
    	mutex_init(&sp->members_lock);
    	sp->members_count = 0;
    	return &sp->group;
    
     fail:
    	kfree(sp);
    	kfree(nds);
    	return ERR_PTR(-ENOMEM);
    }
    
    static void drop_space(struct config_group *g, struct config_item *i)
    {
    	struct dlm_space *sp = config_item_to_space(i);
    
    	/* assert list_empty(&sp->members) */
    
    	configfs_remove_default_groups(&sp->group);
    	config_item_put(i);
    }
    
    static void release_space(struct config_item *i)
    {
    	struct dlm_space *sp = config_item_to_space(i);
    	kfree(sp);
    }
    
    static struct config_item *make_comm(struct config_group *g, const char *name)
    {
    	struct dlm_comm *cm;
    
    	cm = kzalloc(sizeof(struct dlm_comm), GFP_NOFS);
    	if (!cm)
    		return ERR_PTR(-ENOMEM);
    
    	config_item_init_type_name(&cm->item, name, &comm_type);
    
    	cm->seq = dlm_comm_count++;
    	if (!cm->seq)
    		cm->seq = dlm_comm_count++;
    
    	cm->nodeid = -1;
    	cm->local = 0;
    	cm->addr_count = 0;
    	return &cm->item;
    }
    
    static void drop_comm(struct config_group *g, struct config_item *i)
    {
    	struct dlm_comm *cm = config_item_to_comm(i);
    	if (local_comm == cm)
    		local_comm = NULL;
    	dlm_lowcomms_close(cm->nodeid);
    	while (cm->addr_count--)
    		kfree(cm->addr[cm->addr_count]);
    	config_item_put(i);
    }
    
    static void release_comm(struct config_item *i)
    {
    	struct dlm_comm *cm = config_item_to_comm(i);
    	kfree(cm);
    }
    
    static struct config_item *make_node(struct config_group *g, const char *name)
    {
    	struct dlm_space *sp = config_item_to_space(g->cg_item.ci_parent);
    	struct dlm_node *nd;
    
    	nd = kzalloc(sizeof(struct dlm_node), GFP_NOFS);
    	if (!nd)
    		return ERR_PTR(-ENOMEM);
    
    	config_item_init_type_name(&nd->item, name, &node_type);
    	nd->nodeid = -1;
    	nd->weight = 1;  /* default weight of 1 if none is set */
    	nd->new = 1;     /* set to 0 once it's been read by dlm_nodeid_list() */
    
    	mutex_lock(&sp->members_lock);
    	list_add(&nd->list, &sp->members);
    	sp->members_count++;
    	mutex_unlock(&sp->members_lock);
    
    	return &nd->item;
    }
    
    static void drop_node(struct config_group *g, struct config_item *i)
    {
    	struct dlm_space *sp = config_item_to_space(g->cg_item.ci_parent);
    	struct dlm_node *nd = config_item_to_node(i);
    
    	mutex_lock(&sp->members_lock);
    	list_del(&nd->list);
    	sp->members_count--;
    	mutex_unlock(&sp->members_lock);
    
    	config_item_put(i);
    }
    
    static void release_node(struct config_item *i)
    {
    	struct dlm_node *nd = config_item_to_node(i);
    	kfree(nd);
    }
    
    static struct dlm_clusters clusters_root = {
    	.subsys = {
    		.su_group = {
    			.cg_item = {
    				.ci_namebuf = "dlm",
    				.ci_type = &clusters_type,
    			},
    		},
    	},
    };
    
    int __init dlm_config_init(void)
    {
    	config_group_init(&clusters_root.subsys.su_group);
    	mutex_init(&clusters_root.subsys.su_mutex);
    	return configfs_register_subsystem(&clusters_root.subsys);
    }
    
    void dlm_config_exit(void)
    {
    	configfs_unregister_subsystem(&clusters_root.subsys);
    }
    
    /*
     * Functions for user space to read/write attributes
     */
    
    static ssize_t comm_nodeid_show(struct config_item *item, char *buf)
    {
    	return sprintf(buf, "%d\n", config_item_to_comm(item)->nodeid);
    }
    
    static ssize_t comm_nodeid_store(struct config_item *item, const char *buf,
    				 size_t len)
    {
    	int rc = kstrtoint(buf, 0, &config_item_to_comm(item)->nodeid);
    
    	if (rc)
    		return rc;
    	return len;
    }
    
    static ssize_t comm_local_show(struct config_item *item, char *buf)
    {
    	return sprintf(buf, "%d\n", config_item_to_comm(item)->local);
    }
    
    static ssize_t comm_local_store(struct config_item *item, const char *buf,
    				size_t len)
    {
    	struct dlm_comm *cm = config_item_to_comm(item);
    	int rc = kstrtoint(buf, 0, &cm->local);
    
    	if (rc)
    		return rc;
    	if (cm->local && !local_comm)
    		local_comm = cm;
    	return len;
    }
    
    static ssize_t comm_addr_store(struct config_item *item, const char *buf,
    		size_t len)
    {
    	struct dlm_comm *cm = config_item_to_comm(item);
    	struct sockaddr_storage *addr;
    	int rv;
    
    	if (len != sizeof(struct sockaddr_storage))
    		return -EINVAL;
    
    	if (cm->addr_count >= DLM_MAX_ADDR_COUNT)
    		return -ENOSPC;
    
    	addr = kzalloc(sizeof(*addr), GFP_NOFS);
    	if (!addr)
    		return -ENOMEM;
    
    	memcpy(addr, buf, len);
    
    	rv = dlm_lowcomms_addr(cm->nodeid, addr, len);
    	if (rv) {
    		kfree(addr);
    		return rv;
    	}
    
    	cm->addr[cm->addr_count++] = addr;
    	return len;
    }
    
    static ssize_t comm_addr_list_show(struct config_item *item, char *buf)
    {
    	struct dlm_comm *cm = config_item_to_comm(item);
    	ssize_t s;
    	ssize_t allowance;
    	int i;
    	struct sockaddr_storage *addr;
    	struct sockaddr_in *addr_in;
    	struct sockaddr_in6 *addr_in6;
    	
    	/* Taken from ip6_addr_string() defined in lib/vsprintf.c */
    	char buf0[sizeof("AF_INET6	xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:255.255.255.255\n")];
    	
    
    	/* Derived from SIMPLE_ATTR_SIZE of fs/configfs/file.c */
    	allowance = 4096;
    	buf[0] = '\0';
    
    	for (i = 0; i < cm->addr_count; i++) {
    		addr = cm->addr[i];
    
    		switch(addr->ss_family) {
    		case AF_INET:
    			addr_in = (struct sockaddr_in *)addr;
    			s = sprintf(buf0, "AF_INET	%pI4\n", &addr_in->sin_addr.s_addr);
    			break;
    		case AF_INET6:
    			addr_in6 = (struct sockaddr_in6 *)addr;
    			s = sprintf(buf0, "AF_INET6	%pI6\n", &addr_in6->sin6_addr);
    			break;
    		default:
    			s = sprintf(buf0, "%s\n", "<UNKNOWN>");
    			break;
    		}
    		allowance -= s;
    		if (allowance >= 0)
    			strcat(buf, buf0);
    		else {
    			allowance += s;
    			break;
    		}
    	}
    	return 4096 - allowance;
    }
    
    CONFIGFS_ATTR(comm_, nodeid);
    CONFIGFS_ATTR(comm_, local);
    CONFIGFS_ATTR_WO(comm_, addr);
    CONFIGFS_ATTR_RO(comm_, addr_list);
    
    static struct configfs_attribute *comm_attrs[] = {
    	[COMM_ATTR_NODEID] = &comm_attr_nodeid,
    	[COMM_ATTR_LOCAL] = &comm_attr_local,
    	[COMM_ATTR_ADDR] = &comm_attr_addr,
    	[COMM_ATTR_ADDR_LIST] = &comm_attr_addr_list,
    	NULL,
    };
    
    static ssize_t node_nodeid_show(struct config_item *item, char *buf)
    {
    	return sprintf(buf, "%d\n", config_item_to_node(item)->nodeid);
    }
    
    static ssize_t node_nodeid_store(struct config_item *item, const char *buf,
    				 size_t len)
    {
    	struct dlm_node *nd = config_item_to_node(item);
    	uint32_t seq = 0;
    	int rc = kstrtoint(buf, 0, &nd->nodeid);
    
    	if (rc)
    		return rc;
    	dlm_comm_seq(nd->nodeid, &seq);
    	nd->comm_seq = seq;
    	return len;
    }
    
    static ssize_t node_weight_show(struct config_item *item, char *buf)
    {
    	return sprintf(buf, "%d\n", config_item_to_node(item)->weight);
    }
    
    static ssize_t node_weight_store(struct config_item *item, const char *buf,
    				 size_t len)
    {
    	int rc = kstrtoint(buf, 0, &config_item_to_node(item)->weight);
    
    	if (rc)
    		return rc;
    	return len;
    }
    
    CONFIGFS_ATTR(node_, nodeid);
    CONFIGFS_ATTR(node_, weight);
    
    static struct configfs_attribute *node_attrs[] = {
    	[NODE_ATTR_NODEID] = &node_attr_nodeid,
    	[NODE_ATTR_WEIGHT] = &node_attr_weight,
    	NULL,
    };
    
    /*
     * Functions for the dlm to get the info that's been configured
     */
    
    static struct dlm_space *get_space(char *name)
    {
    	struct config_item *i;
    
    	if (!space_list)
    		return NULL;
    
    	mutex_lock(&space_list->cg_subsys->su_mutex);
    	i = config_group_find_item(space_list, name);
    	mutex_unlock(&space_list->cg_subsys->su_mutex);
    
    	return config_item_to_space(i);
    }
    
    static void put_space(struct dlm_space *sp)
    {
    	config_item_put(&sp->group.cg_item);
    }
    
    static struct dlm_comm *get_comm(int nodeid)
    {
    	struct config_item *i;
    	struct dlm_comm *cm = NULL;
    	int found = 0;
    
    	if (!comm_list)
    		return NULL;
    
    	mutex_lock(&clusters_root.subsys.su_mutex);
    
    	list_for_each_entry(i, &comm_list->cg_children, ci_entry) {
    		cm = config_item_to_comm(i);
    
    		if (cm->nodeid != nodeid)
    			continue;
    		found = 1;
    		config_item_get(i);
    		break;
    	}
    	mutex_unlock(&clusters_root.subsys.su_mutex);
    
    	if (!found)
    		cm = NULL;
    	return cm;
    }
    
    static void put_comm(struct dlm_comm *cm)
    {
    	config_item_put(&cm->item);
    }
    
    /* caller must free mem */
    int dlm_config_nodes(char *lsname, struct dlm_config_node **nodes_out,
    		     int *count_out)
    {
    	struct dlm_space *sp;
    	struct dlm_node *nd;
    	struct dlm_config_node *nodes, *node;
    	int rv, count;
    
    	sp = get_space(lsname);
    	if (!sp)
    		return -EEXIST;
    
    	mutex_lock(&sp->members_lock);
    	if (!sp->members_count) {
    		rv = -EINVAL;
    		printk(KERN_ERR "dlm: zero members_count\n");
    		goto out;
    	}
    
    	count = sp->members_count;
    
    	nodes = kcalloc(count, sizeof(struct dlm_config_node), GFP_NOFS);
    	if (!nodes) {
    		rv = -ENOMEM;
    		goto out;
    	}
    
    	node = nodes;
    	list_for_each_entry(nd, &sp->members, list) {
    		node->nodeid = nd->nodeid;
    		node->weight = nd->weight;
    		node->new = nd->new;
    		node->comm_seq = nd->comm_seq;
    		node++;
    
    		nd->new = 0;
    	}
    
    	*count_out = count;
    	*nodes_out = nodes;
    	rv = 0;
     out:
    	mutex_unlock(&sp->members_lock);
    	put_space(sp);
    	return rv;
    }
    
    int dlm_comm_seq(int nodeid, uint32_t *seq)
    {
    	struct dlm_comm *cm = get_comm(nodeid);
    	if (!cm)
    		return -EEXIST;
    	*seq = cm->seq;
    	put_comm(cm);
    	return 0;
    }
    
    int dlm_our_nodeid(void)
    {
    	return local_comm ? local_comm->nodeid : 0;
    }
    
    /* num 0 is first addr, num 1 is second addr */
    int dlm_our_addr(struct sockaddr_storage *addr, int num)
    {
    	if (!local_comm)
    		return -1;
    	if (num + 1 > local_comm->addr_count)
    		return -1;
    	memcpy(addr, local_comm->addr[num], sizeof(*addr));
    	return 0;
    }
    
    /* Config file defaults */
    #define DEFAULT_TCP_PORT       21064
    #define DEFAULT_BUFFER_SIZE     4096
    #define DEFAULT_RSBTBL_SIZE     1024
    #define DEFAULT_RECOVER_TIMER      5
    #define DEFAULT_TOSS_SECS         10
    #define DEFAULT_SCAN_SECS          5
    #define DEFAULT_LOG_DEBUG          0
    #define DEFAULT_PROTOCOL           0
    #define DEFAULT_TIMEWARN_CS      500 /* 5 sec = 500 centiseconds */
    #define DEFAULT_WAITWARN_US	   0
    #define DEFAULT_NEW_RSB_COUNT    128
    #define DEFAULT_RECOVER_CALLBACKS  0
    #define DEFAULT_CLUSTER_NAME      ""
    
    struct dlm_config_info dlm_config = {
    	.ci_tcp_port = DEFAULT_TCP_PORT,
    	.ci_buffer_size = DEFAULT_BUFFER_SIZE,
    	.ci_rsbtbl_size = DEFAULT_RSBTBL_SIZE,
    	.ci_recover_timer = DEFAULT_RECOVER_TIMER,
    	.ci_toss_secs = DEFAULT_TOSS_SECS,
    	.ci_scan_secs = DEFAULT_SCAN_SECS,
    	.ci_log_debug = DEFAULT_LOG_DEBUG,
    	.ci_protocol = DEFAULT_PROTOCOL,
    	.ci_timewarn_cs = DEFAULT_TIMEWARN_CS,
    	.ci_waitwarn_us = DEFAULT_WAITWARN_US,
    	.ci_new_rsb_count = DEFAULT_NEW_RSB_COUNT,
    	.ci_recover_callbacks = DEFAULT_RECOVER_CALLBACKS,
    	.ci_cluster_name = DEFAULT_CLUSTER_NAME
    };