panic if proc doing unlock is not proc that aquired the lock

[unix-history] / usr / src / sys / ufs / ufs / ufs_ihash.c

/*
 * Copyright (c) 1982, 1986, 1989, 1991 Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 *
 *	@(#)ufs_ihash.c	7.8 (Berkeley) %G%
 */

#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(dev, ino)	(((dev) + (ino)) & ihash)

/*
 * Initialize inode hash table.
 */
void
ufs_ihashinit()
{

	ihashtbl = hashinit(desiredvnodes, M_UFSMNT, &ihash);
}

/*
 * Use the dev/ino 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(dev, ino)
	dev_t dev;
	ino_t ino;
{
	register struct inode **ipp, *ip;

	ipp = &ihashtbl[INOHASH(dev, ino)];
loop:
	for (ip = *ipp; ip; ip = ip->i_next) {
		if (ino != ip->i_number || dev != ip->i_dev)
			continue;
		return (ITOV(ip));
	}
	return (NULL);
}

/*
 * Use the dev/ino 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(dev, ino)
	dev_t dev;
	ino_t ino;
{
	register struct inode **ipp, *ip;
	struct vnode *vp;

	ipp = &ihashtbl[INOHASH(dev, ino)];
loop:
	for (ip = *ipp; ip; ip = ip->i_next) {
		if (ino != ip->i_number || dev != ip->i_dev)
			continue;
		if ((ip->i_flag & ILOCKED) != 0) {
			ip->i_flag |= IWANT;
			sleep((caddr_t)ip, PINOD);
			goto loop;
		}
		vp = ITOV(ip);
		if (vget(vp))
			goto loop;
		return (vp);
	}
	return (NULL);
}

/*
 * 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)];
	if (iq = *ipp)
		iq->i_prev = &ip->i_next;
	ip->i_next = iq;
	ip->i_prev = ipp;
	*ipp = ip;
	if ((ip->i_flag & ILOCKED) != 0)
		panic("ufs_ihashins: already locked");
	if (curproc)
		ip->i_lockholder = curproc->p_pid;
	else
		ip->i_lockholder = -1;
	ip->i_flag |= ILOCKED;
}

/*
 * Remove the inode from the hash table.
 */
void
ufs_ihashrem(ip)
	register struct inode *ip;
{
	register struct inode *iq;

	if (iq = ip->i_next)
		iq->i_prev = ip->i_prev;
	*ip->i_prev = iq;
#ifdef DIAGNOSTIC
	ip->i_next = NULL;
	ip->i_prev = NULL;
#endif
}