freebsd-skq/sys/gnu/ext2fs/ext2_ihash.c

170 lines
4.5 KiB
C

/*-
* 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.
* 4. 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
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/mutex.h>
#include <gnu/ext2fs/inode.h>
#include <gnu/ext2fs/ext2_extern.h>
static MALLOC_DEFINE(M_EXT2IHASH, "EXT2 ihash", "EXT2 Inode hash tables");
/*
* Structures associated with inode cacheing.
*/
static LIST_HEAD(ihashhead, inode) *ihashtbl;
static u_long ihash; /* size of hash table - 1 */
#define INOHASH(device, inum) (&ihashtbl[(minor(device) + (inum)) & ihash])
static struct mtx ext2_ihash_mtx;
/*
* Initialize inode hash table.
*/
void
ext2_ihashinit()
{
KASSERT(ihashtbl == NULL, ("ext2_ihashinit called twice"));
ihashtbl = hashinit(desiredvnodes, M_EXT2IHASH, &ihash);
mtx_init(&ext2_ihash_mtx, "ext2 ihash", NULL, MTX_DEF);
}
/*
* Destroy the inode hash table.
*/
void
ext2_ihashuninit()
{
hashdestroy(ihashtbl, M_EXT2IHASH, ihash);
mtx_destroy(&ext2_ihash_mtx);
}
/*
* 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 vnode *
ext2_ihashlookup(dev, inum)
struct cdev *dev;
ino_t inum;
{
struct inode *ip;
mtx_lock(&ext2_ihash_mtx);
LIST_FOREACH(ip, INOHASH(dev, inum), i_hash)
if (inum == ip->i_number && dev == ip->i_dev)
break;
mtx_unlock(&ext2_ihash_mtx);
if (ip)
return (ITOV(ip));
return (NULLVP);
}
/*
* Use the device/inum pair to find the incore inode, and return a pointer
* to it. If it is in core, but locked, wait for it.
*/
int
ext2_ihashget(dev, inum, flags, vpp)
struct cdev *dev;
ino_t inum;
int flags;
struct vnode **vpp;
{
struct thread *td = curthread; /* XXX */
struct inode *ip;
struct vnode *vp;
int error;
*vpp = NULL;
loop:
mtx_lock(&ext2_ihash_mtx);
LIST_FOREACH(ip, INOHASH(dev, inum), i_hash) {
if (inum == ip->i_number && dev == ip->i_dev) {
vp = ITOV(ip);
mtx_lock(&vp->v_interlock);
mtx_unlock(&ext2_ihash_mtx);
error = vget(vp, flags | LK_INTERLOCK, td);
if (error == ENOENT)
goto loop;
if (error)
return (error);
*vpp = vp;
return (0);
}
}
mtx_unlock(&ext2_ihash_mtx);
return (0);
}
/*
* Insert the inode into the hash table, and return it locked.
*/
void
ext2_ihashins(ip)
struct inode *ip;
{
struct thread *td = curthread; /* XXX */
struct ihashhead *ipp;
/* lock the inode, then put it on the appropriate hash list */
vn_lock(ITOV(ip), LK_EXCLUSIVE | LK_RETRY, td);
mtx_lock(&ext2_ihash_mtx);
ipp = INOHASH(ip->i_dev, ip->i_number);
LIST_INSERT_HEAD(ipp, ip, i_hash);
ip->i_flag |= IN_HASHED;
mtx_unlock(&ext2_ihash_mtx);
}
/*
* Remove the inode from the hash table.
*/
void
ext2_ihashrem(ip)
struct inode *ip;
{
mtx_lock(&ext2_ihash_mtx);
if (ip->i_flag & IN_HASHED) {
ip->i_flag &= ~IN_HASHED;
LIST_REMOVE(ip, i_hash);
}
mtx_unlock(&ext2_ihash_mtx);
}