path: root/fs/ocfs2/slot_map.c

/* -*- mode: c; c-basic-offset: 8; -*-
 * vim: noexpandtab sw=8 ts=8 sts=0:
 *
 * slot_map.c
 *
 *
 *
 * 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/types.h>
#include <linux/slab.h>
#include <linux/highmem.h>

#include <cluster/masklog.h>

#include "ocfs2.h"

#include "dlmglue.h"
#include "extent_map.h"
#include "heartbeat.h"
#include "inode.h"
#include "slot_map.h"
#include "super.h"
#include "sysfile.h"
#include "ocfs2_trace.h"

#include "buffer_head_io.h"


struct ocfs2_slot {
	int sl_valid;
	unsigned int sl_node_num;
};

struct ocfs2_slot_info {
	int si_extended;
	int si_slots_per_block;
	struct inode *si_inode;
	unsigned int si_blocks;
	struct buffer_head **si_bh;
	unsigned int si_num_slots;
	struct ocfs2_slot *si_slots;
};


static int __ocfs2_node_num_to_slot(struct ocfs2_slot_info *si,
				    unsigned int node_num);

static void ocfs2_invalidate_slot(struct ocfs2_slot_info *si,
				  int slot_num)
{
	BUG_ON((slot_num < 0) || (slot_num >= si->si_num_slots));
	si->si_slots[slot_num].sl_valid = 0;
}

static void ocfs2_set_slot(struct ocfs2_slot_info *si,
			   int slot_num, unsigned int node_num)
{
	BUG_ON((slot_num < 0) || (slot_num >= si->si_num_slots));

	si->si_slots[slot_num].sl_valid = 1;
	si->si_slots[slot_num].sl_node_num = node_num;
}

/* This version is for the extended slot map */
static void ocfs2_update_slot_info_extended(struct ocfs2_slot_info *si)
{
	int b, i, slotno;
	struct ocfs2_slot_map_extended *se;

	slotno = 0;
	for (b = 0; b < si->si_blocks; b++) {
		se = (struct ocfs2_slot_map_extended *)si->si_bh[b]->b_data;
		for (i = 0;
		     (i < si->si_slots_per_block) &&
		     (slotno < si->si_num_slots);
		     i++, slotno++) {
			if (se->se_slots[i].es_valid)
				ocfs2_set_slot(si, slotno,
					       le32_to_cpu(se->se_slots[i].es_node_num));
			else
				ocfs2_invalidate_slot(si, slotno);
		}
	}
}

/*
 * Post the slot information on disk into our slot_info struct.
 * Must be protected by osb_lock.
 */
static void ocfs2_update_slot_info_old(struct ocfs2_slot_info *si)
{
	int i;
	struct ocfs2_slot_map *sm;

	sm = (struct ocfs2_slot_map *)si->si_bh[0]->b_data;

	for (i = 0; i < si->si_num_slots; i++) {
		if (le16_to_cpu(sm->sm_slots[i]) == (u16)OCFS2_INVALID_SLOT)
			ocfs2_invalidate_slot(si, i);
		else
			ocfs2_set_slot(si, i, le16_to_cpu(sm->sm_slots[i]));
	}
}

static void ocfs2_update_slot_info(struct ocfs2_slot_info *si)
{
	/*
	 * The slot data will have been refreshed when ocfs2_super_lock
	 * was taken.
	 */
	if (si->si_extended)
		ocfs2_update_slot_info_extended(si);
	else
		ocfs2_update_slot_info_old(si);
}

int ocfs2_refresh_slot_info(struct ocfs2_super *osb)
{
	int ret;
	struct ocfs2_slot_info *si = osb->slot_info;

	if (si == NULL)
		return 0;

	BUG_ON(si->si_blocks == 0);
	BUG_ON(si->si_bh == NULL);

	trace_ocfs2_refresh_slot_info(si->si_blocks);

	/*
	 * We pass -1 as blocknr because we expect all of si->si_bh to
	 * be !NULL.  Thus, ocfs2_read_blocks() will ignore blocknr.  If
	 * this is not true, the read of -1 (UINT64_MAX) will fail.
	 */
	ret = ocfs2_read_blocks(INODE_CACHE(si->si_inode), -1, si->si_blocks,
				si->si_bh, OCFS2_BH_IGNORE_CACHE, NULL);
	if (ret == 0) {
		spin_lock(&osb->osb_lock);
		ocfs2_update_slot_info(si);
		spin_unlock(&osb->osb_lock);
	}

	return ret;
}

/* post the our slot info stuff into it's destination bh and write it
 * out. */
static void ocfs2_update_disk_slot_extended(struct ocfs2_slot_info *si,
					    int slot_num,
					    struct buffer_head **bh)
{
	int blkind = slot_num / si->si_slots_per_block;
	int slotno = slot_num % si->si_slots_per_block;
	struct ocfs2_slot_map_extended *se;

	BUG_ON(blkind >= si->si_blocks);

	se = (struct ocfs2_slot_map_extended *)si->si_bh[blkind]->b_data;'n858' href='#n858'>858