/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * Copyright (C) 2004, 2005, 2012 Oracle.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public
 * License along with this program; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 021110-1307, USA.
 */

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/configfs.h>

#include "tcp.h"
#include "nodemanager.h"
#include "heartbeat.h"
#include "masklog.h"

/* for now we operate under the assertion that there can be only one
 * cluster active at a time.  Changing this will require trickling
 * cluster references throughout where nodes are looked up */
struct r2nm_cluster *r2nm_single_cluster;

char *r2nm_fence_method_desc[R2NM_FENCE_METHODS] = {
                "reset",        /* R2NM_FENCE_RESET */
                "panic",        /* R2NM_FENCE_PANIC */
};

struct r2nm_node *r2nm_get_node_by_num(u8 node_num)
{
        struct r2nm_node *node = NULL;

        if (node_num >= R2NM_MAX_NODES || r2nm_single_cluster == NULL)
                goto out;

        read_lock(&r2nm_single_cluster->cl_nodes_lock);
        node = r2nm_single_cluster->cl_nodes[node_num];
        if (node)
                config_item_get(&node->nd_item);
        read_unlock(&r2nm_single_cluster->cl_nodes_lock);
out:
        return node;
}
EXPORT_SYMBOL_GPL(r2nm_get_node_by_num);

int r2nm_configured_node_map(unsigned long *map, unsigned bytes)
{
        struct r2nm_cluster *cluster = r2nm_single_cluster;

        BUG_ON(bytes < (sizeof(cluster->cl_nodes_bitmap)));

        if (cluster == NULL)
                return -EINVAL;

        read_lock(&cluster->cl_nodes_lock);
        memcpy(map, cluster->cl_nodes_bitmap, sizeof(cluster->cl_nodes_bitmap));
        read_unlock(&cluster->cl_nodes_lock);

        return 0;
}
EXPORT_SYMBOL_GPL(r2nm_configured_node_map);

static struct r2nm_node *r2nm_node_ip_tree_lookup(struct r2nm_cluster *cluster,
                                                  __be32 ip_needle,
                                                  struct rb_node ***ret_p,
                                                  struct rb_node **ret_parent)
{
        struct rb_node **p = &cluster->cl_node_ip_tree.rb_node;
        struct rb_node *parent = NULL;
        struct r2nm_node *node, *ret = NULL;

        while (*p) {
                int cmp;

                parent = *p;
                node = rb_entry(parent, struct r2nm_node, nd_ip_node);

                cmp = memcmp(&ip_needle, &node->nd_ipv4_address,
                                sizeof(ip_needle));
                if (cmp < 0)
                        p = &(*p)->rb_left;
                else if (cmp > 0)
                        p = &(*p)->rb_right;
                else {
                        ret = node;
                        break;
                }
        }

        if (ret_p != NULL)
                *ret_p = p;
        if (ret_parent != NULL)
                *ret_parent = parent;

        return ret;
}

struct r2nm_node *r2nm_get_node_by_ip(__be32 addr)
{
        struct r2nm_node *node = NULL;
        struct r2nm_cluster *cluster = r2nm_single_cluster;

        if (cluster == NULL)
                goto out;

        read_lock(&cluster->cl_nodes_lock);
        node = r2nm_node_ip_tree_lookup(cluster, addr, NULL, NULL);
        if (node)
                config_item_get(&node->nd_item);
        read_unlock(&cluster->cl_nodes_lock);

out:
        return node;
}
EXPORT_SYMBOL_GPL(r2nm_get_node_by_ip);

void r2nm_node_put(struct r2nm_node *node)
{
        config_item_put(&node->nd_item);
}
EXPORT_SYMBOL_GPL(r2nm_node_put);

void r2nm_node_get(struct r2nm_node *node)
{
        config_item_get(&node->nd_item);
}
EXPORT_SYMBOL_GPL(r2nm_node_get);

u8 r2nm_this_node(void)
{
        u8 node_num = R2NM_MAX_NODES;

        if (r2nm_single_cluster && r2nm_single_cluster->cl_has_local)
                node_num = r2nm_single_cluster->cl_local_node;

        return node_num;
}
EXPORT_SYMBOL_GPL(r2nm_this_node);

/* node configfs bits */

static struct r2nm_cluster *to_r2nm_cluster(struct config_item *item)
{
        return item ?
                container_of(to_config_group(item), struct r2nm_cluster,
                             cl_group)
                : NULL;
}

static struct r2nm_node *to_r2nm_node(struct config_item *item)
{
        return item ? container_of(item, struct r2nm_node, nd_item) : NULL;
}

static void r2nm_node_release(struct config_item *item)
{
        struct r2nm_node *node = to_r2nm_node(item);
        kfree(node);
}

static ssize_t r2nm_node_num_read(struct r2nm_node *node, char *page)
{
        return sprintf(page, "%d\n", node->nd_num);
}

static struct r2nm_cluster *to_r2nm_cluster_from_node(struct r2nm_node *node)
{
        /* through the first node_set .parent
         * mycluster/nodes/mynode == r2nm_cluster->r2nm_node_group->r2nm_node */
        return to_r2nm_cluster(node->nd_item.ci_parent->ci_parent);
}

enum {
        R2NM_NODE_ATTR_NUM = 0,
        R2NM_NODE_ATTR_PORT,
        R2NM_NODE_ATTR_ADDRESS,
        R2NM_NODE_ATTR_LOCAL,
};

static ssize_t r2nm_node_num_write(struct r2nm_node *node, const char *page,
                                   size_t count)
{
        struct r2nm_cluster *cluster = to_r2nm_cluster_from_node(node);
        unsigned long tmp;
        char *p = (char *)page;
        int err;

        err = kstrtoul(p, 10, &tmp);
        if (err)
                return err;

        if (tmp >= R2NM_MAX_NODES)
                return -ERANGE;

        /* once we're in the cl_nodes tree networking can look us up by
         * node number and try to use our address and port attributes
         * to connect to this node.. make sure that they've been set
         * before writing the node attribute? */
        if (!test_bit(R2NM_NODE_ATTR_ADDRESS, &node->nd_set_attributes) ||
            !test_bit(R2NM_NODE_ATTR_PORT, &node->nd_set_attributes))
                return -EINVAL; /* XXX */

        write_lock(&cluster->cl_nodes_lock);
        if (cluster->cl_nodes[tmp])
                p = NULL;
        else  {
                cluster->cl_nodes[tmp] = node;
                node->nd_num = tmp;
                set_bit(tmp, cluster->cl_nodes_bitmap);
        }
        write_unlock(&cluster->cl_nodes_lock);
        if (p == NULL)
                return -EEXIST;

        return count;
}
static ssize_t r2nm_node_ipv4_port_read(struct r2nm_node *node, char *page)
{
        return sprintf(page, "%u\n", ntohs(node->nd_ipv4_port));
}

static ssize_t r2nm_node_ipv4_port_write(struct r2nm_node *node,
                                         const char *page, size_t count)
{
        unsigned long tmp;
        char *p = (char *)page;
        int err;

        err = kstrtoul(p, 10, &tmp);
        if (err)
                return err;

        if (tmp == 0)
                return -EINVAL;
        if (tmp >= (u16)-1)
                return -ERANGE;

        node->nd_ipv4_port = htons(tmp);

        return count;
}

static ssize_t r2nm_node_ipv4_address_read(struct r2nm_node *node, char *page)
{
        return sprintf(page, "%pI4\n", &node->nd_ipv4_address);
}

static ssize_t r2nm_node_ipv4_address_write(struct r2nm_node *node,
                                            const char *page,
                                            size_t count)
{
        struct r2nm_cluster *cluster = to_r2nm_cluster_from_node(node);
        int ret, i;
        struct rb_node **p, *parent;
        unsigned int octets[4];
        __be32 ipv4_addr = 0;

        ret = sscanf(page, "%3u.%3u.%3u.%3u", &octets[3], &octets[2],
                     &octets[1], &octets[0]);
        if (ret != 4)
                return -EINVAL;

        for (i = 0; i < ARRAY_SIZE(octets); i++) {
                if (octets[i] > 255)
                        return -ERANGE;
                be32_add_cpu(&ipv4_addr, octets[i] << (i * 8));
        }

        ret = 0;
        write_lock(&cluster->cl_nodes_lock);
        if (r2nm_node_ip_tree_lookup(cluster, ipv4_addr, &p, &parent))
                ret = -EEXIST;
        else {
                rb_link_node(&node->nd_ip_node, parent, p);
                rb_insert_color(&node->nd_ip_node, &cluster->cl_node_ip_tree);
        }
        write_unlock(&cluster->cl_nodes_lock);
        if (ret)
                return ret;

        memcpy(&node->nd_ipv4_address, &ipv4_addr, sizeof(ipv4_addr));

        return count;
}

static ssize_t r2nm_node_local_read(struct r2nm_node *node, char *page)
{
        return sprintf(page, "%d\n", node->nd_local);
}

static ssize_t r2nm_node_local_write(struct r2nm_node *node, const char *page,
                                     size_t count)
{
        struct r2nm_cluster *cluster = to_r2nm_cluster_from_node(node);
        unsigned long tmp;
        char *p = (char *)page;
        ssize_t ret;
        int err;

        err = kstrtoul(p, 10, &tmp);
        if (err)
                return err;

        tmp = !!tmp; /* boolean of whether this node wants to be local */

        /* setting local turns on networking rx for now so we require having
         * set everything else first */
        if (!test_bit(R2NM_NODE_ATTR_ADDRESS, &node->nd_set_attributes) ||
            !test_bit(R2NM_NODE_ATTR_NUM, &node->nd_set_attributes) ||
            !test_bit(R2NM_NODE_ATTR_PORT, &node->nd_set_attributes))
                return -EINVAL; /* XXX */

        /* the only failure case is trying to set a new local node
         * when a different one is already set */
        if (tmp && tmp == cluster->cl_has_local &&
            cluster->cl_local_node != node->nd_num)
                return -EBUSY;

        /* bring up the rx thread if we're setting the new local node. */
        if (tmp && !cluster->cl_has_local) {
                ret = r2net_start_listening(node);
                if (ret)
                        return ret;
        }

        if (!tmp && cluster->cl_has_local &&
            cluster->cl_local_node == node->nd_num) {
                r2net_stop_listening(node);
                cluster->cl_local_node = R2NM_INVALID_NODE_NUM;
        }

        node->nd_local = tmp;
        if (node->nd_local) {
                cluster->cl_has_local = tmp;
                cluster->cl_local_node = node->nd_num;
        }

        return count;
}

struct r2nm_node_attribute {
        struct configfs_attribute attr;
        ssize_t (*show)(struct r2nm_node *, char *);
        ssize_t (*store)(struct r2nm_node *, const char *, size_t);
};

static struct r2nm_node_attribute r2nm_node_attr_num = {
        .attr   = { .ca_owner = THIS_MODULE,
                    .ca_name = "num",
                    .ca_mode = S_IRUGO | S_IWUSR },
        .show   = r2nm_node_num_read,
        .store  = r2nm_node_num_write,
};

static struct r2nm_node_attribute r2nm_node_attr_ipv4_port = {
        .attr   = { .ca_owner = THIS_MODULE,
                    .ca_name = "ipv4_port",
                    .ca_mode = S_IRUGO | S_IWUSR },
        .show   = r2nm_node_ipv4_port_read,
        .store  = r2nm_node_ipv4_port_write,
};

static struct r2nm_node_attribute r2nm_node_attr_ipv4_address = {
        .attr   = { .ca_owner = THIS_MODULE,
                    .ca_name = "ipv4_address",
                    .ca_mode = S_IRUGO | S_IWUSR },
        .show   = r2nm_node_ipv4_address_read,
        .store  = r2nm_node_ipv4_address_write,
};

static struct r2nm_node_attribute r2nm_node_attr_local = {
        .attr   = { .ca_owner = THIS_MODULE,
                    .ca_name = "local",
                    .ca_mode = S_IRUGO | S_IWUSR },
        .show   = r2nm_node_local_read,
        .store  = r2nm_node_local_write,
};

static struct configfs_attribute *r2nm_node_attrs[] = {
        [R2NM_NODE_ATTR_NUM] = &r2nm_node_attr_num.attr,
        [R2NM_NODE_ATTR_PORT] = &r2nm_node_attr_ipv4_port.attr,
        [R2NM_NODE_ATTR_ADDRESS] = &r2nm_node_attr_ipv4_address.attr,
        [R2NM_NODE_ATTR_LOCAL] = &r2nm_node_attr_local.attr,
        NULL,
};

static int r2nm_attr_index(struct configfs_attribute *attr)
{
        int i;
        for (i = 0; i < ARRAY_SIZE(r2nm_node_attrs); i++) {
                if (attr == r2nm_node_attrs[i])
                        return i;
        }
        BUG();
        return 0;
}

static ssize_t r2nm_node_show(struct config_item *item,
                              struct configfs_attribute *attr,
                              char *page)
{
        struct r2nm_node *node = to_r2nm_node(item);
        struct r2nm_node_attribute *r2nm_node_attr =
                container_of(attr, struct r2nm_node_attribute, attr);
        ssize_t ret = 0;

        if (r2nm_node_attr->show)
                ret = r2nm_node_attr->show(node, page);
        return ret;
}

static ssize_t r2nm_node_store(struct config_item *item,
                               struct configfs_attribute *attr,
                               const char *page, size_t count)
{
        struct r2nm_node *node = to_r2nm_node(item);
        struct r2nm_node_attribute *r2nm_node_attr =
                container_of(attr, struct r2nm_node_attribute, attr);
        ssize_t ret;
        int attr_index = r2nm_attr_index(attr);

        if (r2nm_node_attr->store == NULL) {
                ret = -EINVAL;
                goto out;
        }

        if (test_bit(attr_index, &node->nd_set_attributes))
                return -EBUSY;

        ret = r2nm_node_attr->store(node, page, count);
        if (ret < count)
                goto out;

        set_bit(attr_index, &node->nd_set_attributes);
out:
        return ret;
}

static struct configfs_item_operations r2nm_node_item_ops = {
        .release                = r2nm_node_release,
        .show_attribute         = r2nm_node_show,
        .store_attribute        = r2nm_node_store,
};

static struct config_item_type r2nm_node_type = {
        .ct_item_ops    = &r2nm_node_item_ops,
        .ct_attrs       = r2nm_node_attrs,
        .ct_owner       = THIS_MODULE,
};

/* node set */

struct r2nm_node_group {
        struct config_group ns_group;
        /* some stuff? */
};

#if 0
static struct r2nm_node_group *to_r2nm_node_group(struct config_group *group)
{
        return group ?
                container_of(group, struct r2nm_node_group, ns_group)
                : NULL;
}
#endif

struct r2nm_cluster_attribute {
        struct configfs_attribute attr;
        ssize_t (*show)(struct r2nm_cluster *, char *);
        ssize_t (*store)(struct r2nm_cluster *, const char *, size_t);
};

static ssize_t r2nm_cluster_attr_write(const char *page, ssize_t count,
                                        unsigned int *val)
{
        unsigned long tmp;
        char *p = (char *)page;
        int err;

        err = kstrtoul(p, 10, &tmp);
        if (err)
                return err;

        if (tmp == 0)
                return -EINVAL;
        if (tmp >= (u32)-1)
                return -ERANGE;

        *val = tmp;

        return count;
}

static ssize_t r2nm_cluster_attr_idle_timeout_ms_read(
        struct r2nm_cluster *cluster, char *page)
{
        return sprintf(page, "%u\n", cluster->cl_idle_timeout_ms);
}

static ssize_t r2nm_cluster_attr_idle_timeout_ms_write(
        struct r2nm_cluster *cluster, const char *page, size_t count)
{
        ssize_t ret;
        unsigned int val = 0;

        ret =  r2nm_cluster_attr_write(page, count, &val);

        if (ret > 0) {
                if (cluster->cl_idle_timeout_ms != val
                        && r2net_num_connected_peers()) {
                        mlog(ML_NOTICE,
                             "r2net: cannot change idle timeout after "
                             "the first peer has agreed to it."
                             "  %d connected peers\n",
                             r2net_num_connected_peers());
                        ret = -EINVAL;
                } else if (val <= cluster->cl_keepalive_delay_ms) {
                        mlog(ML_NOTICE, "r2net: idle timeout must be larger "
                             "than keepalive delay\n");
                        ret = -EINVAL;
                } else {
                        cluster->cl_idle_timeout_ms = val;
                }
        }

        return ret;
}

static ssize_t r2nm_cluster_attr_keepalive_delay_ms_read(
        struct r2nm_cluster *cluster, char *page)
{
        return sprintf(page, "%u\n", cluster->cl_keepalive_delay_ms);
}

static ssize_t r2nm_cluster_attr_keepalive_delay_ms_write(
        struct r2nm_cluster *cluster, const char *page, size_t count)
{
        ssize_t ret;
        unsigned int val = 0;

        ret =  r2nm_cluster_attr_write(page, count, &val);

        if (ret > 0) {
                if (cluster->cl_keepalive_delay_ms != val
                    && r2net_num_connected_peers()) {
                        mlog(ML_NOTICE,
                             "r2net: cannot change keepalive delay after"
                             " the first peer has agreed to it."
                             "  %d connected peers\n",
                             r2net_num_connected_peers());
                        ret = -EINVAL;
                } else if (val >= cluster->cl_idle_timeout_ms) {
                        mlog(ML_NOTICE, "r2net: keepalive delay must be "
                             "smaller than idle timeout\n");
                        ret = -EINVAL;
                } else {
                        cluster->cl_keepalive_delay_ms = val;
                }
        }

        return ret;
}

static ssize_t r2nm_cluster_attr_reconnect_delay_ms_read(
        struct r2nm_cluster *cluster, char *page)
{
        return sprintf(page, "%u\n", cluster->cl_reconnect_delay_ms);
}

static ssize_t r2nm_cluster_attr_reconnect_delay_ms_write(
        struct r2nm_cluster *cluster, const char *page, size_t count)
{
        return r2nm_cluster_attr_write(page, count,
                                        &cluster->cl_reconnect_delay_ms);
}

static ssize_t r2nm_cluster_attr_fence_method_read(
        struct r2nm_cluster *cluster, char *page)
{
        ssize_t ret = 0;

        if (cluster)
                ret = sprintf(page, "%s\n",
                              r2nm_fence_method_desc[cluster->cl_fence_method]);
        return ret;
}

static ssize_t r2nm_cluster_attr_fence_method_write(
        struct r2nm_cluster *cluster, const char *page, size_t count)
{
        unsigned int i;

        if (page[count - 1] != '\n')
                goto bail;

        for (i = 0; i < R2NM_FENCE_METHODS; ++i) {
                if (count != strlen(r2nm_fence_method_desc[i]) + 1)
                        continue;
                if (strncasecmp(page, r2nm_fence_method_desc[i], count - 1))
                        continue;
                if (cluster->cl_fence_method != i) {
                        printk(KERN_INFO "ramster: Changing fence method to %s\n",
                               r2nm_fence_method_desc[i]);
                        cluster->cl_fence_method = i;
                }
                return count;
        }

bail:
        return -EINVAL;
}

static struct r2nm_cluster_attribute r2nm_cluster_attr_idle_timeout_ms = {
        .attr   = { .ca_owner = THIS_MODULE,
                    .ca_name = "idle_timeout_ms",
                    .ca_mode = S_IRUGO | S_IWUSR },
        .show   = r2nm_cluster_attr_idle_timeout_ms_read,
        .store  = r2nm_cluster_attr_idle_timeout_ms_write,
};

static struct r2nm_cluster_attribute r2nm_cluster_attr_keepalive_delay_ms = {
        .attr   = { .ca_owner = THIS_MODULE,
                    .ca_name = "keepalive_delay_ms",
                    .ca_mode = S_IRUGO | S_IWUSR },
        .show   = r2nm_cluster_attr_keepalive_delay_ms_read,
        .store  = r2nm_cluster_attr_keepalive_delay_ms_write,
};

static struct r2nm_cluster_attribute r2nm_cluster_attr_reconnect_delay_ms = {
        .attr   = { .ca_owner = THIS_MODULE,
                    .ca_name = "reconnect_delay_ms",
                    .ca_mode = S_IRUGO | S_IWUSR },
        .show   = r2nm_cluster_attr_reconnect_delay_ms_read,
        .store  = r2nm_cluster_attr_reconnect_delay_ms_write,
};

static struct r2nm_cluster_attribute r2nm_cluster_attr_fence_method = {
        .attr   = { .ca_owner = THIS_MODULE,
                    .ca_name = "fence_method",
                    .ca_mode = S_IRUGO | S_IWUSR },
        .show   = r2nm_cluster_attr_fence_method_read,
        .store  = r2nm_cluster_attr_fence_method_write,
};

static struct configfs_attribute *r2nm_cluster_attrs[] = {
        &r2nm_cluster_attr_idle_timeout_ms.attr,
        &r2nm_cluster_attr_keepalive_delay_ms.attr,
        &r2nm_cluster_attr_reconnect_delay_ms.attr,
        &r2nm_cluster_attr_fence_method.attr,
        NULL,
};
static ssize_t r2nm_cluster_show(struct config_item *item,
                                        struct configfs_attribute *attr,
                                        char *page)
{
        struct r2nm_cluster *cluster = to_r2nm_cluster(item);
        struct r2nm_cluster_attribute *r2nm_cluster_attr =
                container_of(attr, struct r2nm_cluster_attribute, attr);
        ssize_t ret = 0;

        if (r2nm_cluster_attr->show)
                ret = r2nm_cluster_attr->show(cluster, page);
        return ret;
}

static ssize_t r2nm_cluster_store(struct config_item *item,
                                        struct configfs_attribute *attr,
                                        const char *page, size_t count)
{
        struct r2nm_cluster *cluster = to_r2nm_cluster(item);
        struct r2nm_cluster_attribute *r2nm_cluster_attr =
                container_of(attr, struct r2nm_cluster_attribute, attr);
        ssize_t ret;

        if (r2nm_cluster_attr->store == NULL) {
                ret = -EINVAL;
                goto out;
        }

        ret = r2nm_cluster_attr->store(cluster, page, count);
        if (ret < count)
                goto out;
out:
        return ret;
}

static struct config_item *r2nm_node_group_make_item(struct config_group *group,
                                                     const char *name)
{
        struct r2nm_node *node = NULL;

        if (strlen(name) > R2NM_MAX_NAME_LEN)
                return ERR_PTR(-ENAMETOOLONG);

        node = kzalloc(sizeof(struct r2nm_node), GFP_KERNEL);
        if (node == NULL)
                return ERR_PTR(-ENOMEM);

        strcpy(node->nd_name, name); /* use item.ci_namebuf instead? */
        config_item_init_type_name(&node->nd_item, name, &r2nm_node_type);
        spin_lock_init(&node->nd_lock);

        mlog(ML_CLUSTER, "r2nm: Registering node %s\n", name);

        return &node->nd_item;
}

static void r2nm_node_group_drop_item(struct config_group *group,
                                      struct config_item *item)
{
        struct r2nm_node *node = to_r2nm_node(item);
        struct r2nm_cluster *cluster =
                                to_r2nm_cluster(group->cg_item.ci_parent);

        r2net_disconnect_node(node);

        if (cluster->cl_has_local &&
            (cluster->cl_local_node == node->nd_num)) {
                cluster->cl_has_local = 0;
                cluster->cl_local_node = R2NM_INVALID_NODE_NUM;
                r2net_stop_listening(node);
        }

        /* XXX call into net to stop this node from trading messages */

        write_lock(&cluster->cl_nodes_lock);

        /* XXX sloppy */
        if (node->nd_ipv4_address)
                rb_erase(&node->nd_ip_node, &cluster->cl_node_ip_tree);

        /* nd_num might be 0 if the node number hasn't been set.. */
        if (cluster->cl_nodes[node->nd_num] == node) {
                cluster->cl_nodes[node->nd_num] = NULL;
                clear_bit(node->nd_num, cluster->cl_nodes_bitmap);
        }
        write_unlock(&cluster->cl_nodes_lock);

        mlog(ML_CLUSTER, "r2nm: Unregistered node %s\n",
             config_item_name(&node->nd_item));

        config_item_put(item);
}

static struct configfs_group_operations r2nm_node_group_group_ops = {
        .make_item      = r2nm_node_group_make_item,
        .drop_item      = r2nm_node_group_drop_item,
};

static struct config_item_type r2nm_node_group_type = {
        .ct_group_ops   = &r2nm_node_group_group_ops,
        .ct_owner       = THIS_MODULE,
};

/* cluster */

static void r2nm_cluster_release(struct config_item *item)
{
        struct r2nm_cluster *cluster = to_r2nm_cluster(item);

        kfree(cluster->cl_group.default_groups);
        kfree(cluster);
}

static struct configfs_item_operations r2nm_cluster_item_ops = {
        .release        = r2nm_cluster_release,
        .show_attribute         = r2nm_cluster_show,
        .store_attribute        = r2nm_cluster_store,
};

static struct config_item_type r2nm_cluster_type = {
        .ct_item_ops    = &r2nm_cluster_item_ops,
        .ct_attrs       = r2nm_cluster_attrs,
        .ct_owner       = THIS_MODULE,
};

/* cluster set */

struct r2nm_cluster_group {
        struct configfs_subsystem cs_subsys;
        /* some stuff? */
};

#if 0
static struct r2nm_cluster_group *
to_r2nm_cluster_group(struct config_group *group)
{
        return group ?
                container_of(to_configfs_subsystem(group),
                                struct r2nm_cluster_group, cs_subsys)
               : NULL;
}
#endif

static struct config_group *
r2nm_cluster_group_make_group(struct config_group *group,
                                                          const char *name)
{
        struct r2nm_cluster *cluster = NULL;
        struct r2nm_node_group *ns = NULL;
        struct config_group *r2hb_group = NULL, *ret = NULL;
        void *defs = NULL;

        /* this runs under the parent dir's i_mutex; there can be only
         * one caller in here at a time */
        if (r2nm_single_cluster)
                return ERR_PTR(-ENOSPC);

        cluster = kzalloc(sizeof(struct r2nm_cluster), GFP_KERNEL);
        ns = kzalloc(sizeof(struct r2nm_node_group), GFP_KERNEL);
        defs = kcalloc(3, sizeof(struct config_group *), GFP_KERNEL);
        r2hb_group = r2hb_alloc_hb_set();
        if (cluster == NULL || ns == NULL || r2hb_group == NULL || defs == NULL)
                goto out;

        config_group_init_type_name(&cluster->cl_group, name,
                                    &r2nm_cluster_type);
        config_group_init_type_name(&ns->ns_group, "node",
                                    &r2nm_node_group_type);

        cluster->cl_group.default_groups = defs;
        cluster->cl_group.default_groups[0] = &ns->ns_group;
        cluster->cl_group.default_groups[1] = r2hb_group;
        cluster->cl_group.default_groups[2] = NULL;
        rwlock_init(&cluster->cl_nodes_lock);
        cluster->cl_node_ip_tree = RB_ROOT;
        cluster->cl_reconnect_delay_ms = R2NET_RECONNECT_DELAY_MS_DEFAULT;
        cluster->cl_idle_timeout_ms    = R2NET_IDLE_TIMEOUT_MS_DEFAULT;
        cluster->cl_keepalive_delay_ms = R2NET_KEEPALIVE_DELAY_MS_DEFAULT;
        cluster->cl_fence_method       = R2NM_FENCE_RESET;

        ret = &cluster->cl_group;
        r2nm_single_cluster = cluster;

out:
        if (ret == NULL) {
                kfree(cluster);
                kfree(ns);
                r2hb_free_hb_set(r2hb_group);
                kfree(defs);
                ret = ERR_PTR(-ENOMEM);
        }

        return ret;
}

static void r2nm_cluster_group_drop_item(struct config_group *group,
                                                struct config_item *item)
{
        struct r2nm_cluster *cluster = to_r2nm_cluster(item);
        int i;
        struct config_item *killme;

        BUG_ON(r2nm_single_cluster != cluster);
        r2nm_single_cluster = NULL;

        for (i = 0; cluster->cl_group.default_groups[i]; i++) {
                killme = &cluster->cl_group.default_groups[i]->cg_item;
                cluster->cl_group.default_groups[i] = NULL;
                config_item_put(killme);
        }

        config_item_put(item);
}

static struct configfs_group_operations r2nm_cluster_group_group_ops = {
        .make_group     = r2nm_cluster_group_make_group,
        .drop_item      = r2nm_cluster_group_drop_item,
};

static struct config_item_type r2nm_cluster_group_type = {
        .ct_group_ops   = &r2nm_cluster_group_group_ops,
        .ct_owner       = THIS_MODULE,
};

static struct r2nm_cluster_group r2nm_cluster_group = {
        .cs_subsys = {
                .su_group = {
                        .cg_item = {
                                .ci_namebuf = "cluster",
                                .ci_type = &r2nm_cluster_group_type,
                        },
                },
        },
};

int r2nm_depend_item(struct config_item *item)
{
        return configfs_depend_item(&r2nm_cluster_group.cs_subsys, item);
}

void r2nm_undepend_item(struct config_item *item)
{
        configfs_undepend_item(&r2nm_cluster_group.cs_subsys, item);
}

int r2nm_depend_this_node(void)
{
        int ret = 0;
        struct r2nm_node *local_node;

        local_node = r2nm_get_node_by_num(r2nm_this_node());
        if (!local_node) {
                ret = -EINVAL;
                goto out;
        }

        ret = r2nm_depend_item(&local_node->nd_item);
        r2nm_node_put(local_node);

out:
        return ret;
}

void r2nm_undepend_this_node(void)
{
        struct r2nm_node *local_node;

        local_node = r2nm_get_node_by_num(r2nm_this_node());
        BUG_ON(!local_node);

        r2nm_undepend_item(&local_node->nd_item);
        r2nm_node_put(local_node);
}


static void __exit exit_r2nm(void)
{
        /* XXX sync with hb callbacks and shut down hb? */
        r2net_unregister_hb_callbacks();
        configfs_unregister_subsystem(&r2nm_cluster_group.cs_subsys);

        r2net_exit();
        r2hb_exit();
}

static int __init init_r2nm(void)
{
        int ret = -1;

        ret = r2hb_init();
        if (ret)
                goto out;

        ret = r2net_init();
        if (ret)
                goto out_r2hb;

        ret = r2net_register_hb_callbacks();
        if (ret)
                goto out_r2net;

        config_group_init(&r2nm_cluster_group.cs_subsys.su_group);
        mutex_init(&r2nm_cluster_group.cs_subsys.su_mutex);
        ret = configfs_register_subsystem(&r2nm_cluster_group.cs_subsys);
        if (ret) {
                printk(KERN_ERR "nodemanager: Registration returned %d\n", ret);
                goto out_callbacks;
        }

        if (!ret)
                goto out;

        configfs_unregister_subsystem(&r2nm_cluster_group.cs_subsys);
out_callbacks:
        r2net_unregister_hb_callbacks();
out_r2net:
        r2net_exit();
out_r2hb:
        r2hb_exit();
out:
        return ret;
}

MODULE_AUTHOR("Oracle");
MODULE_LICENSE("GPL");

module_init(init_r2nm)
module_exit(exit_r2nm)