/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * heartbeat.c
 *
 * Register ourselves with the heartbaet service, keep our node maps
 * up to date, and fire off recovery when needed.
 *
 * Copyright (C) 2002, 2004 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/fs.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>
#include <linux/kmod.h>

#include <cluster/heartbeat.h>
#include <cluster/nodemanager.h>

#include <dlm/dlmapi.h>

#define MLOG_MASK_PREFIX ML_SUPER
#include <cluster/masklog.h>

#include "ocfs2.h"

#include "alloc.h"
#include "heartbeat.h"
#include "inode.h"
#include "journal.h"
#include "vote.h"

#include "buffer_head_io.h"

#define OCFS2_HB_NODE_DOWN_PRI     (0x0000002)
#define OCFS2_HB_NODE_UP_PRI       OCFS2_HB_NODE_DOWN_PRI

static inline void __ocfs2_node_map_set_bit(struct ocfs2_node_map *map,
                                            int bit);
static inline void __ocfs2_node_map_clear_bit(struct ocfs2_node_map *map,
                                              int bit);
static inline int __ocfs2_node_map_is_empty(struct ocfs2_node_map *map);
static void __ocfs2_node_map_dup(struct ocfs2_node_map *target,
                                 struct ocfs2_node_map *from);
static void __ocfs2_node_map_set(struct ocfs2_node_map *target,
                                 struct ocfs2_node_map *from);

void ocfs2_init_node_maps(struct ocfs2_super *osb)
{
        spin_lock_init(&osb->node_map_lock);
        ocfs2_node_map_init(&osb->mounted_map);
        ocfs2_node_map_init(&osb->recovery_map);
        ocfs2_node_map_init(&osb->umount_map);
        ocfs2_node_map_init(&osb->osb_recovering_orphan_dirs);
}

static void ocfs2_do_node_down(int node_num,
                               struct ocfs2_super *osb)
{
        BUG_ON(osb->node_num == node_num);

        mlog(0, "ocfs2: node down event for %d\n", node_num);

        if (!osb->dlm) {
                /*
                 * No DLM means we're not even ready to participate yet.
                 * We check the slots after the DLM comes up, so we will
                 * notice the node death then.  We can safely ignore it
                 * here.
                 */
                return;
        }

        if (ocfs2_node_map_test_bit(osb, &osb->umount_map, node_num)) {
                /* If a node is in the umount map, then we've been
                 * expecting him to go down and we know ahead of time
                 * that recovery is not necessary. */
                ocfs2_node_map_clear_bit(osb, &osb->umount_map, node_num);
                return;
        }

        ocfs2_recovery_thread(osb, node_num);

        ocfs2_remove_node_from_vote_queues(osb, node_num);
}

static void ocfs2_hb_node_down_cb(struct o2nm_node *node,
                                  int node_num,
                                  void *data)
{
        ocfs2_do_node_down(node_num, (struct ocfs2_super *) data);
}

/* Called from the dlm when it's about to evict a node. We may also
 * get a heartbeat callback later. */
static void ocfs2_dlm_eviction_cb(int node_num,
                                  void *data)
{
        struct ocfs2_super *osb = (struct ocfs2_super *) data;
        struct super_block *sb = osb->sb;

        mlog(ML_NOTICE, "device (%u,%u): dlm has evicted node %d\n",
             MAJOR(sb->s_dev), MINOR(sb->s_dev), node_num);

        ocfs2_do_node_down(node_num, osb);
}

static void ocfs2_hb_node_up_cb(struct o2nm_node *node,
                                int node_num,
                                void *data)
{
        struct ocfs2_super *osb = data;

        BUG_ON(osb->node_num == node_num);

        mlog(0, "node up event for %d\n", node_num);
        ocfs2_node_map_clear_bit(osb, &osb->umount_map, node_num);
}

void ocfs2_setup_hb_callbacks(struct ocfs2_super *osb)
{
        o2hb_setup_callback(&osb->osb_hb_down, O2HB_NODE_DOWN_CB,
                            ocfs2_hb_node_down_cb, osb,
                            OCFS2_HB_NODE_DOWN_PRI);

        o2hb_setup_callback(&osb->osb_hb_up, O2HB_NODE_UP_CB,
                            ocfs2_hb_node_up_cb, osb, OCFS2_HB_NODE_UP_PRI);

        /* Not exactly a heartbeat callback, but leads to essentially
         * the same path so we set it up here. */
        dlm_setup_eviction_cb(&osb->osb_eviction_cb,
                              ocfs2_dlm_eviction_cb,
                              osb);
}

/* Most functions here are just stubs for now... */
int ocfs2_register_hb_callbacks(struct ocfs2_super *osb)
{
        int status;

        if (ocfs2_mount_local(osb))
                return 0;

        status = o2hb_register_callback(osb->uuid_str, &osb->osb_hb_down);
        if (status < 0) {
                mlog_errno(status);
                goto bail;
        }

        status = o2hb_register_callback(osb->uuid_str, &osb->osb_hb_up);
        if (status < 0) {
                mlog_errno(status);
                o2hb_unregister_callback(osb->uuid_str, &osb->osb_hb_down);
        }

bail:
        return status;
}

void ocfs2_clear_hb_callbacks(struct ocfs2_super *osb)
{
        if (ocfs2_mount_local(osb))
                return;

        o2hb_unregister_callback(osb->uuid_str, &osb->osb_hb_down);
        o2hb_unregister_callback(osb->uuid_str, &osb->osb_hb_up);
}

void ocfs2_stop_heartbeat(struct ocfs2_super *osb)
{
        int ret;
        char *argv[5], *envp[3];

        if (ocfs2_mount_local(osb))
                return;

        if (!osb->uuid_str) {
                /* This can happen if we don't get far enough in mount... */
                mlog(0, "No UUID with which to stop heartbeat!\n\n");
                return;
        }

        argv[0] = (char *)o2nm_get_hb_ctl_path();
        argv[1] = "-K";
        argv[2] = "-u";
        argv[3] = osb->uuid_str;
        argv[4] = NULL;

        mlog(0, "Run: %s %s %s %s\n", argv[0], argv[1], argv[2], argv[3]);

        /* minimal command environment taken from cpu_run_sbin_hotplug */
        envp[0] = "HOME=/";
        envp[1] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
        envp[2] = NULL;

        ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_PROC);
        if (ret < 0)
                mlog_errno(ret);
}

/* special case -1 for now
 * TODO: should *really* make sure the calling func never passes -1!!  */
void ocfs2_node_map_init(struct ocfs2_node_map *map)
{
        map->num_nodes = OCFS2_NODE_MAP_MAX_NODES;
        memset(map->map, 0, BITS_TO_LONGS(OCFS2_NODE_MAP_MAX_NODES) *
               sizeof(unsigned long));
}

static inline void __ocfs2_node_map_set_bit(struct ocfs2_node_map *map,
                                            int bit)
{
        set_bit(bit, map->map);
}

void ocfs2_node_map_set_bit(struct ocfs2_super *osb,
                            struct ocfs2_node_map *map,
                            int bit)
{
        if (bit==-1)
                return;
        BUG_ON(bit >= map->num_nodes);
        spin_lock(&osb->node_map_lock);
        __ocfs2_node_map_set_bit(map, bit);
        spin_unlock(&osb->node_map_lock);
}

static inline void __ocfs2_node_map_clear_bit(struct ocfs2_node_map *map,
                                              int bit)
{
        clear_bit(bit, map->map);
}

void ocfs2_node_map_clear_bit(struct ocfs2_super *osb,
                              struct ocfs2_node_map *map,
                              int bit)
{
        if (bit==-1)
                return;
        BUG_ON(bit >= map->num_nodes);
        spin_lock(&osb->node_map_lock);
        __ocfs2_node_map_clear_bit(map, bit);
        spin_unlock(&osb->node_map_lock);
}

int ocfs2_node_map_test_bit(struct ocfs2_super *osb,
                            struct ocfs2_node_map *map,
                            int bit)
{
        int ret;
        if (bit >= map->num_nodes) {
                mlog(ML_ERROR, "bit=%d map->num_nodes=%d\n", bit, map->num_nodes);
                BUG();
        }
        spin_lock(&osb->node_map_lock);
        ret = test_bit(bit, map->map);
        spin_unlock(&osb->node_map_lock);
        return ret;
}

static inline int __ocfs2_node_map_is_empty(struct ocfs2_node_map *map)
{
        int bit;
        bit = find_next_bit(map->map, map->num_nodes, 0);
        if (bit < map->num_nodes)
                return 0;
        return 1;
}

int ocfs2_node_map_is_empty(struct ocfs2_super *osb,
                            struct ocfs2_node_map *map)
{
        int ret;
        BUG_ON(map->num_nodes == 0);
        spin_lock(&osb->node_map_lock);
        ret = __ocfs2_node_map_is_empty(map);
        spin_unlock(&osb->node_map_lock);
        return ret;
}

static void __ocfs2_node_map_dup(struct ocfs2_node_map *target,
                                 struct ocfs2_node_map *from)
{
        BUG_ON(from->num_nodes == 0);
        ocfs2_node_map_init(target);
        __ocfs2_node_map_set(target, from);
}

/* returns 1 if bit is the only bit set in target, 0 otherwise */
int ocfs2_node_map_is_only(struct ocfs2_super *osb,
                           struct ocfs2_node_map *target,
                           int bit)
{
        struct ocfs2_node_map temp;
        int ret;

        spin_lock(&osb->node_map_lock);
        __ocfs2_node_map_dup(&temp, target);
        __ocfs2_node_map_clear_bit(&temp, bit);
        ret = __ocfs2_node_map_is_empty(&temp);
        spin_unlock(&osb->node_map_lock);

        return ret;
}

static void __ocfs2_node_map_set(struct ocfs2_node_map *target,
                                 struct ocfs2_node_map *from)
{
        int num_longs, i;

        BUG_ON(target->num_nodes != from->num_nodes);
        BUG_ON(target->num_nodes == 0);

        num_longs = BITS_TO_LONGS(target->num_nodes);
        for (i = 0; i < num_longs; i++)
                target->map[i] = from->map[i];
}

/* Returns whether the recovery bit was actually set - it may not be
 * if a node is still marked as needing recovery */
int ocfs2_recovery_map_set(struct ocfs2_super *osb,
                           int num)
{
        int set = 0;

        spin_lock(&osb->node_map_lock);

        __ocfs2_node_map_clear_bit(&osb->mounted_map, num);

        if (!test_bit(num, osb->recovery_map.map)) {
            __ocfs2_node_map_set_bit(&osb->recovery_map, num);
            set = 1;
        }

        spin_unlock(&osb->node_map_lock);

        return set;
}

void ocfs2_recovery_map_clear(struct ocfs2_super *osb,
                              int num)
{
        ocfs2_node_map_clear_bit(osb, &osb->recovery_map, num);
}

int ocfs2_node_map_iterate(struct ocfs2_super *osb,
                           struct ocfs2_node_map *map,
                           int idx)
{
        int i = idx;

        idx = O2NM_INVALID_NODE_NUM;
        spin_lock(&osb->node_map_lock);
        if ((i != O2NM_INVALID_NODE_NUM) &&
            (i >= 0) &&
            (i < map->num_nodes)) {
                while(i < map->num_nodes) {
                        if (test_bit(i, map->map)) {
                                idx = i;
                                break;
                        }
                        i++;
                }
        }
        spin_unlock(&osb->node_map_lock);
        return idx;
}