/*
 * Copyright (c) 1982, 1986, 1989, 1991, 1993, 1995
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)ufs_ihash.c 8.7 (Berkeley) 5/17/95
 * $FreeBSD: src/sys/fs/hpfs/hpfs_hash.c,v 1.1 1999/12/09 19:09:58 semenu Exp $
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/malloc.h>
#include <sys/proc.h>

#include "hpfs.h"

MALLOC_DEFINE(M_HPFSHASH, "HPFS hash", "HPFS node hash tables");

/*
 * Structures associated with hpfsnode cacheing.
 */
static LIST_HEAD(hphashhead, hpfsnode) *hpfs_hphashtbl;
static u_long   hpfs_hphash;            /* size of hash table - 1 */
#define HPNOHASH(dev, lsn)      (&hpfs_hphashtbl[(minor(dev) + (lsn)) & hpfs_hphash])
#ifndef NULL_SIMPLELOCKS
static struct lwkt_token hpfs_hphash_token;
#endif
struct lock hpfs_hphash_lock;

/*
 * Initialize inode hash table.
 */
void
hpfs_hphashinit(void)
{
        int hsize = vfs_inodehashsize();

        lockinit(&hpfs_hphash_lock, "hpfs_hphashlock", 0, 0);
        hpfs_hphashtbl = hashinit(hsize, M_HPFSHASH, &hpfs_hphash);
        lwkt_token_init(&hpfs_hphash_token, "hpfsihash");
}

/*
 * Free the inode hash.
 */
int
hpfs_hphash_uninit(struct vfsconf *vfc)
{
        lwkt_gettoken(&hpfs_hphash_token);
        if (hpfs_hphashtbl)
                hashdestroy(hpfs_hphashtbl, M_HPFSHASH, hpfs_hphash);
        lwkt_reltoken(&hpfs_hphash_token);

        return 0;
}

/*
 * Use the device/inum pair to find the incore inode, and return a pointer
 * to it. If it is in core, return it, even if it is locked.
 */
struct hpfsnode *
hpfs_hphashlookup(cdev_t dev, lsn_t ino)
{
        struct hpfsnode *hp;

        lwkt_gettoken(&hpfs_hphash_token);
        for (hp = HPNOHASH(dev, ino)->lh_first; hp; hp = hp->h_hash.le_next) {
                if (ino == hp->h_no && dev == hp->h_dev)
                        break;
        }
        lwkt_reltoken(&hpfs_hphash_token);

        return (hp);
}

struct vnode *
hpfs_hphashvget(cdev_t dev, lsn_t ino)
{
        struct hpfsnode *hp;
        struct vnode *vp;

        lwkt_gettoken(&hpfs_hphash_token);
loop:
        for (hp = HPNOHASH(dev, ino)->lh_first; hp; hp = hp->h_hash.le_next) {
                if (ino != hp->h_no || dev != hp->h_dev)
                        continue;
                vp = HPTOV(hp);

                if (vget(vp, LK_EXCLUSIVE))
                        goto loop;
                /*
                 * We must check to see if the inode has been ripped
                 * out from under us after blocking.
                 */
                for (hp = HPNOHASH(dev, ino)->lh_first; hp; hp = hp->h_hash.le_next) {
                        if (ino == hp->h_no && dev == hp->h_dev)
                                break;
                }
                if (hp == NULL || vp != HPTOV(hp)) {
                        vput(vp);
                        goto loop;
                }

                /*
                 * Or if the vget fails (due to a race)
                 */
                lwkt_reltoken(&hpfs_hphash_token);
                return (vp);
        }
        lwkt_reltoken(&hpfs_hphash_token);
        return (NULLVP);
}

/*
 * Insert the hpfsnode into the hash table.
 */
void
hpfs_hphashins(struct hpfsnode *hp)
{
        struct hphashhead *hpp;

        lwkt_gettoken(&hpfs_hphash_token);
        hpp = HPNOHASH(hp->h_dev, hp->h_no);
        hp->h_flag |= H_HASHED;
        LIST_INSERT_HEAD(hpp, hp, h_hash);
        lwkt_reltoken(&hpfs_hphash_token);
}

/*
 * Remove the inode from the hash table.
 */
void
hpfs_hphashrem(struct hpfsnode *hp)
{
        lwkt_gettoken(&hpfs_hphash_token);
        if (hp->h_flag & H_HASHED) {
                hp->h_flag &= ~H_HASHED;
                LIST_REMOVE(hp, h_hash);
#ifdef DIAGNOSTIC
                hp->h_hash.le_next = NULL;
                hp->h_hash.le_prev = NULL;
#endif
        }
        lwkt_reltoken(&hpfs_hphash_token);
}