/******************************************************************************
*******************************************************************************
**
**  Copyright (C) 2005-2009 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 "dlm_internal.h"
#include "lockspace.h"
#include "member.h"
#include "recoverd.h"
#include "recover.h"
#include "rcom.h"
#include "config.h"
#include "lowcomms.h"

int dlm_slots_version(struct dlm_header *h)
{
	if ((h->h_version & 0x0000FFFF) < DLM_HEADER_SLOTS)
		return 0;
	return 1;
}

void dlm_slot_save(struct dlm_ls *ls, struct dlm_rcom *rc,
		  struct dlm_member *memb)
{
	struct rcom_config *rf = (struct rcom_config *)rc->rc_buf;

	if (!dlm_slots_version(&rc->rc_header))
		return;

	memb->slot = le16_to_cpu(rf->rf_our_slot);
	memb->generation = le32_to_cpu(rf->rf_generation);
}

void dlm_slots_copy_out(struct dlm_ls *ls, struct dlm_rcom *rc)
{
	struct dlm_slot *slot;
	struct rcom_slot *ro;
	int i;

	ro = (struct rcom_slot *)(rc->rc_buf + sizeof(struct rcom_config));

	/* ls_slots array is sparse, but not rcom_slots */

	for (i = 0; i < ls->ls_slots_size; i++) {
		slot = &ls->ls_slots[i];
		if (!slot->nodeid)
			continue;
		ro->ro_nodeid = cpu_to_le32(slot->nodeid);
		ro->ro_slot = cpu_to_le16(slot->slot);
		ro++;
	}
}

#define SLOT_DEBUG_LINE 128

static void log_debug_slots(struct dlm_ls *ls, uint32_t gen, int num_slots,
			    struct rcom_slot *ro0, struct dlm_slot *array,
			    int array_size)
{
	char line[SLOT_DEBUG_LINE];
	int len = SLOT_DEBUG_LINE - 1;
	int pos = 0;
	int ret, i;

	if (!dlm_config.ci_log_debug)
		return;

	memset(line, 0, sizeof(line));

	if (array) {
		for (i = 0; i < array_size; i++) {
			if (!array[i].nodeid)
				continue;

			ret = snprintf(line + pos, len - pos, " %d:%d",
				       array[i].slot, array[i].nodeid);
			if (ret >= len - pos)
				break;
			pos += ret;
		}
	} else if (ro0) {
		for (i = 0; i < num_slots; i++) {
			ret = snprintf(line + pos, len - pos, " %d:%d",
				       ro0[i].ro_slot, ro0[i].ro_nodeid);
			if (ret >= len - pos)
				break;
			pos += ret;
		}
	}

	log_debug(ls, "generation %u slots %d%s", gen, num_slots, line);
}

int dlm_slots_copy_in(struct dlm_ls *ls)
{
	struct dlm_member *memb;
	struct dlm_rcom *rc = ls->ls_recover_buf;
	struct rcom_config *rf = (struct rcom_config *)rc->rc_buf;
	struct rcom_slot *ro0, *ro;
	int our_nodeid = dlm_our_nodeid();
	int i, num_slots;
	uint32_t gen;

	if (!dlm_slots_version(&rc->rc_header))
		return -1;

	gen = le32_to_cpu(rf->rf_generation);
	if (gen <= ls->ls_generation) {
		log_error(ls, "dlm_slots_copy_in gen %u old %u",
			  gen, ls->ls_generation);
	}
	ls->ls_generation = gen;

	num_slots = le16_to_cpu(rf->rf_num_slots);
	if (!num_slots)
		return -1;

	ro0 = (struct rcom_slot *)(rc->rc_buf + sizeof(struct rcom_config));

	for (i = 0, ro = ro0; i < num_slots; i++, ro++) {
		ro->ro_nodeid = le32_to_cpu(ro->ro_nodeid);
		ro->ro_slot = le16_to_cpu(ro->ro_slot);
	}

	log_debug_slots(ls, gen, num_slots, ro0, NULL, 0);

	list_for_each_entry(memb, &ls->ls_nodes, list) {
		for (i = 0, ro = ro0; i < num_slots; i++, ro++) {
			if (ro->ro_nodeid != memb->nodeid)
				continue;
			memb->slot = ro->ro_slot;
			memb->slot_prev = memb->slot;
			break;
		}

		if (memb->nodeid == our_nodeid) {
			if (ls->ls_slot && ls->ls_slot != memb->slot) {
				log_error(ls, "dlm_slots_copy_in our slot "
					  "changed %d %d", ls->ls_slot,
					  memb->slot);
				return -1;
			}

			if (!ls->ls_slot)
				ls->ls_slot = memb->slot;
		}

		if (!memb->slot) {
			log_error(ls, "dlm_slots_copy_in nodeid %d no slot",
				   memb->nodeid);
			return -1;
		}
	}

	return 0;
}

/* for any nodes that do not support slots, we will not have set memb->slot
   in wait_status_all(), so memb->slot will remain -1, and we will not
   assign slots or set ls_num_slots here */

int dlm_slots_assign(struct dlm_ls *ls, int *num_slots, int *slots_size,
		     struct dlm_slot **slots_out, uint32_t *gen_out)
{
	struct dlm_member *memb;
	struct dlm_slot *array;
	int our_nodeid = dlm_our_nodeid();
	int array_size, max_slots, i;
	int need = 0;
	int max = 0;
	int num = 0;
	uint32_t gen = 0;

	/* our own memb struct will have slot -1 gen 0 */

	list_for_each_entry(memb, &ls->ls_nodes, list) {
		if (memb->nodeid == our_nodeid) {
			memb->slot = ls->ls_slot;
			memb->generation = ls->ls_generation;
			break;
		}
	}

	list_for_each_entry(memb, &ls->ls_nodes, list) {
		if (memb->generation > gen)
			gen = memb->generation;

		/* node doesn't support slots */

		if (memb->slot == -1)
			return -1;

		/* node needs a slot assigned */

		if (!memb->slot)
			need++;

		/* node has a slot assigned */

		num++;

		if (!max || max < memb->slot)
			max = memb->slot;

		/* sanity check, once slot is assigned it shouldn't change */

		if (memb->slot_prev && memb->slot && memb->slot_prev != memb->slot) {
			log_error(ls, "nodeid %d slot changed %d %d",
				  memb->nodeid, memb->slot_prev, memb->slot);
			return -1;
		}
		memb->slot_prev = memb->slot;
	}

	array_size = max + need;

	array = kzalloc(array_size * sizeof(struct dlm_slot), GFP_NOFS);
	if (!array)
		return -ENOMEM;

	num = 0;

	/* fill in slots (offsets) that are used */

	list_for_each_entry(memb, &ls->ls_nodes, list) {
		if (!memb->slot)
			continue;

		if (memb->slot > array_size) {
			log_error(ls, "invalid slot number %d", memb->slot);
			kfree(array);
			return -1;
		}

		array[memb->slot - 1].nodeid = memb->nodeid;
		array[memb->slot - 1].slot = memb->slot;
		num++;
	}

	/* assign new slots from unused offsets */

	list_for_each_entry(memb, &ls->ls_nodes, list) {
		if (memb->slot)
			continue;

		for (i = 0; i < array_size; i++) {
			if (array[i].nodeid)
				continue;

			memb->slot = i + 1;
			memb->slot_prev = memb->slot;
			array[i].nodeid = memb->nodeid;
			array[i].slot = memb->slot;
			num++;

			if (!ls->ls_slot && memb->nodeid == our_nodeid)
				ls->ls_slot = memb->slot;
			break;
		}

		if (!memb->slot) {
			log_error(ls, "no free slot found");
			kfree(array);
			return -1;
		}
	}

	gen++;

	log_debug_slots(ls, gen, num, NULL, array, array_size);

	max_slots = (dlm_config.ci_buffer_size - sizeof(struct dlm_rcom) -
		     sizeof(struct rcom_config)) / sizeof(struct rcom_slot);

	if (num > max_slots) {
		log_error(ls, "num_slots %d exceeds max_slots %d",
			  num, max_slots);
		kfree(array);
		return -1;
	}

	*gen_out = gen;
	*slots_out = array;
	*slots_size = array_size;
	*num_slots = num;
	return 0;
}

static void add_ordered_member(struct dlm_ls *ls, struct dlm_member *new)
{
	struct dlm_member *memb = NULL;
	struct list_head *tmp;
	struct list_head *newlist = &new->list;
	struct list_head *head = &ls->ls_nodes;

	list_for_each(tmp, head) {
		memb = list_entry(tmp, struct dlm_member, list);
		if (new->nodeid < memb->nodeid)
			break;
	}

	if (!memb)
		list_add_tail(newlist, head);
	else {
		/* FIXME: can use list macro here */
		newlist->prev = tmp->prev;
		newlist->next = tmp;
		tmp->prev->next = newlist;
		tmp->prev = newlist;
	}
}

static int dlm_add_member(struct dlm_ls *ls, int nodeid)
{
	struct dlm_member *memb;
	int w, error;

	memb = kzalloc(sizeof(struct dlm_member), GFP_NOFS);
	if (!memb)
		return -ENOMEM;

	w = dlm_node_weight(ls->ls_name, nodeid);
	if (w < 0) {
		kfree(memb);
		return w;
	}

	error = dlm_lowcomms_connect_node(nodeid);
	if (error < 0) {
		kfree(memb);
		return error;
	}

	memb->nodeid = nodeid;
	memb->weight = w;
	add_ordered_member(ls, memb);
	ls->ls_num_nodes++;
	return 0;
}

static void dlm_remove_member(struct dlm_ls *ls, struct dlm_member *memb)
{
	list_move(&memb->list, &ls->ls_nodes_gone);
	ls->ls_num_nodes--;
}

int dlm_is_member(struct dlm_ls *ls, int nodeid)
{
	struct dlm_member *memb;

	list_for_each_entry(memb, &ls->ls_nodes, list) {
		if (memb->nodeid == nodeid)
			return 1;
	}
	return 0;
}

int dlm_is_removed(struct dlm_ls *ls, int nodeid)
{
	struct dlm_member *memb;

	list_for_each_entry(memb, &ls->ls_nodes_gone, list) {
		if (memb->nodeid == nodeid)
			return 1;
	}
	return 0;
}

static void clear_memb_list(struct list_head *head)
{
	struct dlm_member *memb;

	while (!list_empty(head)) {
		memb = list_entry(head->next, struct dlm_member, list);
		list_del(&memb->list);
		kfree(memb);
	}
}

void dlm_clear_members(struct dlm_ls *ls)
{
	clear_memb_list(&ls->ls_nodes);
	ls->ls_num_nodes = 0;
}

void dlm_clear_members_gone(struct dlm_ls *ls)
{
	clear_memb_list(&ls->ls_nodes_gone);
}

static void make_member_array(struct dlm_ls *ls)
{
	struct dlm_member *memb;
	int i, w, x = 0, total = 0, all_zero = 0, *array;

	kfree(ls->ls_node_array);
	ls->ls_node_array = NULL;

	list_for_each_entry(memb, &ls->ls_nodes, list) {
		if (memb->weight)
			total += memb->weight;
	}

	/* all nodes revert to weight of 1 if all have weight 0 */

	if (!total) {
		total = ls->ls_num_nodes;
		all_zero = 1;
	}

	ls->ls_total_weight = total;

	array = kmalloc(sizeof(int) * total, GFP_NOFS);
	if (!array)
		return;

	list_for_each_entry(memb, &ls->ls_nodes, list) {
		if (!all_zero && !memb->weight)
			continue;

		if (all_zero)
			w = 1;
		else
			w = memb->weight;

		DLM_ASSERT(x < total, printk("total %d x %d\n", total, x););

		for (i = 0; i < w; i++)
			array[x++] = memb->nodeid;
	}

	ls->ls_node_array = array;
}

/* send a status request to all members just to establish comms connections */

static int ping_members(struct dlm_ls *ls)
{
	struct dlm_member *memb;
	int error = 0;

	list_for_each_entry(memb, &ls->ls_nodes, list) {
		error = dlm_recovery_stopped(ls);
		if (error)
			break;
		error = dlm_rcom_status(ls, memb->nodeid, 0);
		if (error)
			break;
	}
	if (error)
		log_debug(ls, "ping_members aborted %d last nodeid %d",
			  error, ls->ls_recover_nodeid);
	return error;
}

int dlm_recover_members(struct dlm_ls *ls, struct dlm_recover *rv, int *neg_out)
{
	struct dlm_member *memb, *safe;
	int i, error, found, pos = 0, neg = 0, low = -1;

	/* previously removed members that we've not finished removing need to
	   count as a negative change so the "neg" recovery steps will happen */

	list_for_each_entry(memb, &ls->ls_nodes_gone, list) {
		log_debug(ls, "prev removed member %d", memb->nodeid);
		neg++;
	}

	/* move departed members from ls_nodes to ls_nodes_gone */

	list_for_each_entry_safe(memb, safe, &ls->ls_nodes, list) {
		found = 0;
		for (i = 0; i < rv->node_count; i++) {
			if (memb->nodeid == rv->nodeids[i]) {
				found = 1;
				break;
			}
		}

		if (!found) {
			neg++;
			dlm_remove_member(ls, memb);
			log_debug(ls, "remove member %d", memb->nodeid);
		}
	}

	/* Add an entry to ls_nodes_gone for members that were removed and
	   then added again, so that previous state for these nodes will be
	   cleared during recovery. */

	for (i = 0; i < rv->new_count; i++) {
		if (!dlm_is_member(ls, rv->new[i]))
			continue;
		log_debug(ls, "new nodeid %d is a re-added member", rv->new[i]);

		memb = kzalloc(sizeof(struct dlm_member), GFP_NOFS);
		if (!memb)
			return -ENOMEM;
		memb->nodeid = rv->new[i];
		list_add_tail(&memb->list, &ls->ls_nodes_gone);
		neg++;
	}

	/* add new members to ls_nodes */

	for (i = 0; i < rv->node_count; i++) {
		if (dlm_is_member(ls, rv->nodeids[i]))
			continue;
		dlm_add_member(ls, rv->nodeids[i]);
		pos++;
		log_debug(ls, "add member %d", rv->nodeids[i]);
	}

	list_for_each_entry(memb, &ls->ls_nodes, list) {
		if (low == -1 || memb->nodeid < low)
			low = memb->nodeid;
	}
	ls->ls_low_nodeid = low;

	make_member_array(ls);
	*neg_out = neg;

	error = ping_members(ls);
	if (!error || error == -EPROTO) {
		/* new_lockspace() may be waiting to know if the config
		   is good or bad */
		ls->ls_members_result = error;
		complete(&ls->ls_members_done);
	}

	log_debug(ls, "dlm_recover_members %d nodes", ls->ls_num_nodes);
	return error;
}

/* Userspace guarantees that dlm_ls_stop() has completed on all nodes before
   dlm_ls_start() is called on any of them to start the new recovery. */

int dlm_ls_stop(struct dlm_ls *ls)
{
	int new;

	/*
	 * Prevent dlm_recv from being in the middle of something when we do
	 * the stop.  This includes ensuring dlm_recv isn't processing a
	 * recovery message (rcom), while dlm_recoverd is aborting and
	 * resetting things from an in-progress recovery.  i.e. we want
	 * dlm_recoverd to abort its recovery without worrying about dlm_recv
	 * processing an rcom at the same time.  Stopping dlm_recv also makes
	 * it easy for dlm_receive_message() to check locking stopped and add a
	 * message to the requestqueue without races.
	 */

	down_write(&ls->ls_recv_active);

	/*
	 * Abort any recovery that's in progress (see RECOVERY_STOP,
	 * dlm_recovery_stopped()) and tell any other threads running in the
	 * dlm to quit any processing (see RUNNING, dlm_locking_stopped()).
	 */

	spin_lock(&ls->ls_recover_lock);
	set_bit(LSFL_RECOVERY_STOP, &ls->ls_flags);
	new = test_and_clear_bit(LSFL_RUNNING, &ls->ls_flags);
	ls->ls_recover_seq++;
	spin_unlock(&ls->ls_recover_lock);

	/*
	 * Let dlm_recv run again, now any normal messages will be saved on the
	 * requestqueue for later.
	 */

	up_write(&ls->ls_recv_active);

	/*
	 * This in_recovery lock does two things:
	 * 1) Keeps this function from returning until all threads are out
	 *    of locking routines and locking is truly stopped.
	 * 2) Keeps any new requests from being processed until it's unlocked
	 *    when recovery is complete.
	 */

	if (new)
		down_write(&ls->ls_in_recovery);

	/*
	 * The recoverd suspend/resume makes sure that dlm_recoverd (if
	 * running) has noticed RECOVERY_STOP above and quit processing the
	 * previous recovery.
	 */

	dlm_recoverd_suspend(ls);

	spin_lock(&ls->ls_recover_lock);
	kfree(ls->ls_slots);
	ls->ls_slots = NULL;
	ls->ls_num_slots = 0;
	ls->ls_slots_size = 0;
	ls->ls_recover_status = 0;
	spin_unlock(&ls->ls_recover_lock);

	dlm_recoverd_resume(ls);

	if (!ls->ls_recover_begin)
		ls->ls_recover_begin = jiffies;
	return 0;
}

int dlm_ls_start(struct dlm_ls *ls)
{
	struct dlm_recover *rv = NULL, *rv_old;
	int *ids = NULL, *new = NULL;
	int error, ids_count = 0, new_count = 0;

	rv = kzalloc(sizeof(struct dlm_recover), GFP_NOFS);
	if (!rv)
		return -ENOMEM;

	error = dlm_nodeid_list(ls->ls_name, &ids, &ids_count,
				&new, &new_count);
	if (error < 0)
		goto fail;

	spin_lock(&ls->ls_recover_lock);

	/* the lockspace needs to be stopped before it can be started */

	if (!dlm_locking_stopped(ls)) {
		spin_unlock(&ls->ls_recover_lock);
		log_error(ls, "start ignored: lockspace running");
		error = -EINVAL;
		goto fail;
	}

	rv->nodeids = ids;
	rv->node_count = ids_count;
	rv->new = new;
	rv->new_count = new_count;
	rv->seq = ++ls->ls_recover_seq;
	rv_old = ls->ls_recover_args;
	ls->ls_recover_args = rv;
	spin_unlock(&ls->ls_recover_lock);

	if (rv_old) {
		log_error(ls, "unused recovery %llx %d",
			  (unsigned long long)rv_old->seq, rv_old->node_count);
		kfree(rv_old->nodeids);
		kfree(rv_old->new);
		kfree(rv_old);
	}

	dlm_recoverd_kick(ls);
	return 0;

 fail:
	kfree(rv);
	kfree(ids);
	kfree(new);
	return error;
}