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

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/*
* Copyright (c) 1982, 1986, 1989, 1991, 1993
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 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 8.4 (Berkeley) 12/30/93
* $Id: ufs_ihash.c,v 1.4 1994/10/08 06:57:23 phk Exp $
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*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <ufs/ufs/quota.h>
#include <ufs/ufs/inode.h>
#include <ufs/ufs/ufs_extern.h>
/*
* Structures associated with inode cacheing.
*/
struct inode **ihashtbl;
u_long ihash; /* size of hash table - 1 */
#define INOHASH(device, inum) (((device) + (inum)) & ihash)
/*
* Initialize inode hash table.
*/
void
ufs_ihashinit()
{
ihashtbl = hashinit(desiredvnodes, M_UFSMNT, &ihash);
}
/*
* 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 *
ufs_ihashlookup(device, inum)
dev_t device;
ino_t inum;
{
register struct inode *ip;
for (ip = ihashtbl[INOHASH(device, inum)];; ip = ip->i_next) {
if (ip == NULL)
return (NULL);
if (inum == ip->i_number && device == ip->i_dev)
return (ITOV(ip));
}
/* NOTREACHED */
}
/*
* 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.
*/
struct vnode *
ufs_ihashget(device, inum)
dev_t device;
ino_t inum;
{
register struct inode *ip;
struct vnode *vp;
for (;;)
for (ip = ihashtbl[INOHASH(device, inum)];; ip = ip->i_next) {
if (ip == NULL)
return (NULL);
if (inum == ip->i_number && device == ip->i_dev) {
if (ip->i_flag & IN_LOCKED) {
if( curproc->p_pid != ip->i_lockholder) {
ip->i_flag |= IN_WANTED;
(void) tsleep(ip, PINOD, "uihget", 0);
break;
} else if (ip->i_flag & IN_RECURSE) {
ip->i_lockcount++;
} else {
panic("ufs_ihashget: recursive lock not expected -- pid %d\n", ip->i_lockholder);
}
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}
vp = ITOV(ip);
if (!vget(vp, 1))
return (vp);
break;
}
}
/* NOTREACHED */
}
/*
* Insert the inode into the hash table, and return it locked.
*/
void
ufs_ihashins(ip)
struct inode *ip;
{
struct inode **ipp, *iq;
ipp = &ihashtbl[INOHASH(ip->i_dev, ip->i_number)];
iq = *ipp;
if (iq)
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iq->i_prev = &ip->i_next;
ip->i_next = iq;
ip->i_prev = ipp;
*ipp = ip;
if ((ip->i_flag & IN_LOCKED) &&
((ip->i_flag & IN_RECURSE) == 0 ||
(!curproc || (curproc && (ip->i_lockholder != curproc->p_pid)))))
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panic("ufs_ihashins: already locked");
if (curproc) {
ip->i_lockcount += 1;
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ip->i_lockholder = curproc->p_pid;
} else {
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ip->i_lockholder = -1;
}
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ip->i_flag |= IN_LOCKED;
}
/*
* Remove the inode from the hash table.
*/
void
ufs_ihashrem(ip)
register struct inode *ip;
{
register struct inode *iq;
iq = ip->i_next;
if (iq)
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iq->i_prev = ip->i_prev;
*ip->i_prev = iq;
#ifdef DIAGNOSTIC
ip->i_next = NULL;
ip->i_prev = NULL;
#endif
}