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ufs_ihash.c

/*    $OpenBSD: ufs_ihash.c,v 1.10 2004/12/26 21:22:14 miod Exp $ */
/*    $NetBSD: ufs_ihash.c,v 1.3 1996/02/09 22:36:04 christos Exp $     */

/*
 * 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. 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
 */

#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.
 */
LIST_HEAD(ihashhead, inode) *ihashtbl;
u_long      ihash;            /* size of hash table - 1 */
#define     INOHASH(device, inum)   (&ihashtbl[((device) + (inum)) & ihash])
struct simplelock ufs_ihash_slock;

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

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

/*
 * 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(dev, inum)
      dev_t dev;
      ino_t inum;
{
        struct inode *ip;

      simple_lock(&ufs_ihash_slock);
      LIST_FOREACH(ip, INOHASH(dev, inum), i_hash)
            if (inum == ip->i_number && dev == ip->i_dev)
                  break;
      simple_unlock(&ufs_ihash_slock);

      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.
 */
struct vnode *
ufs_ihashget(dev, inum)
      dev_t dev;
      ino_t inum;
{
      struct proc *p = curproc;
      struct inode *ip;
      struct vnode *vp;
loop:
      simple_lock(&ufs_ihash_slock);
      LIST_FOREACH(ip, INOHASH(dev, inum), i_hash) {
            if (inum == ip->i_number && dev == ip->i_dev) {
                  vp = ITOV(ip);
                  simple_lock(&vp->v_interlock);
                  simple_unlock(&ufs_ihash_slock);
                  if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK, p))
                        goto loop;
                  return (vp);
            }
      }
      simple_unlock(&ufs_ihash_slock);
      return (NULL);
}

/*
 * Insert the inode into the hash table, and return it locked.
 */
int
ufs_ihashins(ip)
      struct inode *ip;
{
      struct inode *curip;
      struct proc *p = curproc;           /* XXX */
      struct ihashhead *ipp;
      dev_t  dev = ip->i_dev;
      ino_t  inum = ip->i_number;

      /* lock the inode, then put it on the appropriate hash list */
      lockmgr(&ip->i_lock, LK_EXCLUSIVE, (struct simplelock *)0, p);

      simple_lock(&ufs_ihash_slock);

      LIST_FOREACH(curip, INOHASH(dev, inum), i_hash) {
            if (inum == curip->i_number && dev == curip->i_dev) {
                    simple_unlock(&ufs_ihash_slock);
                  lockmgr(&ip->i_lock, LK_RELEASE, (struct simplelock *)0, p);
                  return (EEXIST);
            }
      }

      ipp = INOHASH(dev, inum);
      LIST_INSERT_HEAD(ipp, ip, i_hash);
      simple_unlock(&ufs_ihash_slock);

      return (0);
}

/*
 * Remove the inode from the hash table.
 */
void
ufs_ihashrem(ip)
      struct inode *ip;
{
      simple_lock(&ufs_ihash_slock);

      if (ip->i_hash.le_prev == NULL)
            return;

      LIST_REMOVE(ip, i_hash);
#ifdef DIAGNOSTIC
      ip->i_hash.le_next = NULL;
      ip->i_hash.le_prev = NULL;
#endif
      simple_unlock(&ufs_ihash_slock);

}

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