minix/sys/ufs/chfs/chfs_vnode_cache.c

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/* $NetBSD: chfs_vnode_cache.c,v 1.3 2012/10/19 12:44:39 ttoth Exp $ */
/*-
* Copyright (c) 2010 Department of Software Engineering,
* University of Szeged, Hungary
* Copyright (C) 2010 Tamas Toth <ttoth@inf.u-szeged.hu>
* Copyright (C) 2010 Adam Hoka <ahoka@NetBSD.org>
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by the Department of Software Engineering, University of Szeged, Hungary
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
#include "chfs.h"
#include <sys/pool.h>
/* vnode cache is a hashtable for vnodes */
/* chfs_vnocache_hash_init - initializing the hashtable */
struct chfs_vnode_cache **
chfs_vnocache_hash_init(void)
{
return kmem_zalloc(VNODECACHE_SIZE *
sizeof(struct chfs_vnode_cache *), KM_SLEEP);
}
/*
* chfs_vnode_cache_get - get a vnode_cache from the hashtable
* Returns the vnode_cache.
*/
struct chfs_vnode_cache *
chfs_vnode_cache_get(struct chfs_mount *chmp, ino_t vno)
{
struct chfs_vnode_cache* ret;
KASSERT(mutex_owned(&chmp->chm_lock_vnocache));
ret = chmp->chm_vnocache_hash[vno % VNODECACHE_SIZE];
if (ret == NULL) {
return NULL;
}
while (ret && ret->vno < vno) {
ret = ret->next;
}
if (ret && ret->vno != vno) {
ret = NULL;
}
return ret;
}
/* chfs_vnode_cache_add - add a vnode_cache to the hashtable */
void
chfs_vnode_cache_add(struct chfs_mount *chmp,
struct chfs_vnode_cache* new)
{
struct chfs_vnode_cache** prev;
KASSERT(mutex_owned(&chmp->chm_lock_vnocache));
if (!new->vno) {
new->vno = ++chmp->chm_max_vno;
}
prev = &chmp->chm_vnocache_hash[new->vno % VNODECACHE_SIZE];
while ((*prev) && (*prev)->vno < new->vno) {
prev = &((*prev)->next);
}
new->next = *prev;
*prev = new;
}
/* chfs_vnode_cache_remove - removes a vnode_cache from the hashtable */
void
chfs_vnode_cache_remove(struct chfs_mount *chmp,
struct chfs_vnode_cache* old)
{
struct chfs_vnode_cache** prev;
KASSERT(mutex_owned(&chmp->chm_lock_vnocache));
prev = &chmp->chm_vnocache_hash[old->vno % VNODECACHE_SIZE];
while ((*prev) && (*prev)->vno < old->vno) {
prev = &(*prev)->next;
}
if ((*prev) == old) {
*prev = old->next;
}
if (old->state != VNO_STATE_READING &&
old->state != VNO_STATE_CLEARING) {
chfs_vnode_cache_free(old);
}
}
/* chfs_vnocache_hash_destroy - destroying the vnode cache */
void
chfs_vnocache_hash_destroy(struct chfs_vnode_cache **hash)
{
struct chfs_vnode_cache *this, *next;
int i;
/* free every row */
for (i = 0; i < VNODECACHE_SIZE; i++) {
this = hash[i];
while (this) {
next = this->next;
chfs_vnode_cache_free(this);
this = next;
}
hash[i] = NULL;
}
}