sys/vfs/hpfs/hpfs_hash.c

   1 /*
   2  * Copyright (c) 1982, 1986, 1989, 1991, 1993, 1995
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  *
  29  *      @(#)ufs_ihash.c 8.7 (Berkeley) 5/17/95
  30  * $FreeBSD: src/sys/fs/hpfs/hpfs_hash.c,v 1.1 1999/12/09 19:09:58 semenu Exp $
  31  */
  32
  33 #include <sys/param.h>
  34 #include <sys/systm.h>
  35 #include <sys/kernel.h>
  36 #include <sys/lock.h>
  37 #include <sys/vnode.h>
  38 #include <sys/mount.h>
  39 #include <sys/malloc.h>
  40 #include <sys/proc.h>
  41
  42 #include "hpfs.h"
  43
  44 MALLOC_DEFINE(M_HPFSHASH, "HPFS hash", "HPFS node hash tables");
  45
  46 /*
  47  * Structures associated with hpfsnode cacheing.
  48  */
  49 static LIST_HEAD(hphashhead, hpfsnode) *hpfs_hphashtbl;
  50 static u_long   hpfs_hphash;            /* size of hash table - 1 */
  51 #define HPNOHASH(dev, lsn)      (&hpfs_hphashtbl[(minor(dev) + (lsn)) & hpfs_hphash])
  52 #ifndef NULL_SIMPLELOCKS
  53 static struct lwkt_token hpfs_hphash_token;
  54 #endif
  55 struct lock hpfs_hphash_lock;
  56
  57 /*
  58  * Initialize inode hash table.
  59  */
  60 void
  61 hpfs_hphashinit(void)
  62 {
  63
  64         lockinit (&hpfs_hphash_lock, "hpfs_hphashlock", 0, 0);
  65         hpfs_hphashtbl = hashinit(desiredvnodes, M_HPFSHASH, &hpfs_hphash);
  66         lwkt_token_init(&hpfs_hphash_token, "hpfsihash");
  67 }
  68
  69 /*
  70  * Free the inode hash.
  71  */
  72 int
  73 hpfs_hphash_uninit(struct vfsconf *vfc)
  74 {
  75         lwkt_gettoken(&hpfs_hphash_token);
  76         if (hpfs_hphashtbl)
  77                 hashdestroy(hpfs_hphashtbl, M_HPFSHASH, hpfs_hphash);
  78         lwkt_reltoken(&hpfs_hphash_token);
  79
  80         return 0;
  81 }
  82
  83 /*
  84  * Use the device/inum pair to find the incore inode, and return a pointer
  85  * to it. If it is in core, return it, even if it is locked.
  86  */
  87 struct hpfsnode *
  88 hpfs_hphashlookup(cdev_t dev, lsn_t ino)
  89 {
  90         struct hpfsnode *hp;
  91
  92         lwkt_gettoken(&hpfs_hphash_token);
  93         for (hp = HPNOHASH(dev, ino)->lh_first; hp; hp = hp->h_hash.le_next) {
  94                 if (ino == hp->h_no && dev == hp->h_dev)
  95                         break;
  96         }
  97         lwkt_reltoken(&hpfs_hphash_token);
  98
  99         return (hp);
 100 }
 101
 102 struct vnode *
 103 hpfs_hphashvget(cdev_t dev, lsn_t ino)
 104 {
 105         struct hpfsnode *hp;
 106         struct vnode *vp;
 107
 108         lwkt_gettoken(&hpfs_hphash_token);
 109 loop:
 110         for (hp = HPNOHASH(dev, ino)->lh_first; hp; hp = hp->h_hash.le_next) {
 111                 if (ino != hp->h_no || dev != hp->h_dev)
 112                         continue;
 113                 vp = HPTOV(hp);
 114
 115                 if (vget(vp, LK_EXCLUSIVE))
 116                         goto loop;
 117                 /*
 118                  * We must check to see if the inode has been ripped
 119                  * out from under us after blocking.
 120                  */
 121                 for (hp = HPNOHASH(dev, ino)->lh_first; hp; hp = hp->h_hash.le_next) {
 122                         if (ino == hp->h_no && dev == hp->h_dev)
 123                                 break;
 124                 }
 125                 if (hp == NULL || vp != HPTOV(hp)) {
 126                         vput(vp);
 127                         goto loop;
 128                 }
 129
 130                 /*
 131                  * Or if the vget fails (due to a race)
 132                  */
 133                 lwkt_reltoken(&hpfs_hphash_token);
 134                 return (vp);
 135         }
 136         lwkt_reltoken(&hpfs_hphash_token);
 137         return (NULLVP);
 138 }
 139
 140 /*
 141  * Insert the hpfsnode into the hash table.
 142  */
 143 void
 144 hpfs_hphashins(struct hpfsnode *hp)
 145 {
 146         struct hphashhead *hpp;
 147
 148         lwkt_gettoken(&hpfs_hphash_token);
 149         hpp = HPNOHASH(hp->h_dev, hp->h_no);
 150         hp->h_flag |= H_HASHED;
 151         LIST_INSERT_HEAD(hpp, hp, h_hash);
 152         lwkt_reltoken(&hpfs_hphash_token);
 153 }
 154
 155 /*
 156  * Remove the inode from the hash table.
 157  */
 158 void
 159 hpfs_hphashrem(struct hpfsnode *hp)
 160 {
 161         lwkt_gettoken(&hpfs_hphash_token);
 162         if (hp->h_flag & H_HASHED) {
 163                 hp->h_flag &= ~H_HASHED;
 164                 LIST_REMOVE(hp, h_hash);
 165 #ifdef DIAGNOSTIC
 166                 hp->h_hash.le_next = NULL;
 167                 hp->h_hash.le_prev = NULL;
 168 #endif
 169         }
 170         lwkt_reltoken(&hpfs_hphash_token);
 171 }