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. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)ufs_ihash.c 8.7 (Berkeley) 5/17/95
  34  * $FreeBSD: src/sys/fs/hpfs/hpfs_hash.c,v 1.1 1999/12/09 19:09:58 semenu Exp $
  35  * $DragonFly: src/sys/vfs/hpfs/hpfs_hash.c,v 1.16 2006/09/10 01:26:40 dillon Exp $
  36  */
  37
  38 #include <sys/param.h>
  39 #include <sys/systm.h>
  40 #include <sys/kernel.h>
  41 #include <sys/lock.h>
  42 #include <sys/vnode.h>
  43 #include <sys/mount.h>
  44 #include <sys/malloc.h>
  45 #include <sys/proc.h>
  46
  47 #include "hpfs.h"
  48
  49 MALLOC_DEFINE(M_HPFSHASH, "HPFS hash", "HPFS node hash tables");
  50
  51 /*
  52  * Structures associated with hpfsnode cacheing.
  53  */
  54 static LIST_HEAD(hphashhead, hpfsnode) *hpfs_hphashtbl;
  55 static u_long   hpfs_hphash;            /* size of hash table - 1 */
  56 #define HPNOHASH(dev, lsn)      (&hpfs_hphashtbl[(minor(dev) + (lsn)) & hpfs_hphash])
  57 #ifndef NULL_SIMPLELOCKS
  58 static struct lwkt_token hpfs_hphash_token;
  59 #endif
  60 struct lock hpfs_hphash_lock;
  61
  62 /*
  63  * Initialize inode hash table.
  64  */
  65 void
  66 hpfs_hphashinit(void)
  67 {
  68
  69         lockinit (&hpfs_hphash_lock, "hpfs_hphashlock", 0, 0);
  70         hpfs_hphashtbl = HASHINIT(desiredvnodes, M_HPFSHASH, M_WAITOK,
  71             &hpfs_hphash);
  72         lwkt_token_init(&hpfs_hphash_token);
  73 }
  74
  75 /*
  76  * Free the inode hash.
  77  */
  78 int
  79 hpfs_hphash_uninit(struct vfsconf *vfc)
  80 {
  81         lwkt_tokref ilock;
  82
  83         lwkt_gettoken(&ilock, &hpfs_hphash_token);
  84         if (hpfs_hphashtbl)
  85                 kfree(hpfs_hphashtbl, M_HPFSHASH);
  86         lwkt_reltoken(&ilock);
  87
  88         return 0;
  89 }
  90
  91 /*
  92  * Use the device/inum pair to find the incore inode, and return a pointer
  93  * to it. If it is in core, return it, even if it is locked.
  94  */
  95 struct hpfsnode *
  96 hpfs_hphashlookup(cdev_t dev, lsn_t ino)
  97 {
  98         struct hpfsnode *hp;
  99         lwkt_tokref ilock;
 100
 101         lwkt_gettoken(&ilock, &hpfs_hphash_token);
 102         for (hp = HPNOHASH(dev, ino)->lh_first; hp; hp = hp->h_hash.le_next) {
 103                 if (ino == hp->h_no && dev == hp->h_dev)
 104                         break;
 105         }
 106         lwkt_reltoken(&ilock);
 107
 108         return (hp);
 109 }
 110
 111 struct vnode *
 112 hpfs_hphashvget(cdev_t dev, lsn_t ino)
 113 {
 114         struct hpfsnode *hp;
 115         lwkt_tokref ilock;
 116         struct vnode *vp;
 117
 118         lwkt_gettoken(&ilock, &hpfs_hphash_token);
 119 loop:
 120         for (hp = HPNOHASH(dev, ino)->lh_first; hp; hp = hp->h_hash.le_next) {
 121                 if (ino != hp->h_no || dev != hp->h_dev)
 122                         continue;
 123                 vp = HPTOV(hp);
 124
 125                 if (vget(vp, LK_EXCLUSIVE))
 126                         goto loop;
 127                 /*
 128                  * We must check to see if the inode has been ripped
 129                  * out from under us after blocking.
 130                  */
 131                 for (hp = HPNOHASH(dev, ino)->lh_first; hp; hp = hp->h_hash.le_next) {
 132                         if (ino == hp->h_no && dev == hp->h_dev)
 133                                 break;
 134                 }
 135                 if (hp == NULL || vp != HPTOV(hp)) {
 136                         vput(vp);
 137                         goto loop;
 138                 }
 139
 140                 /*
 141                  * Or if the vget fails (due to a race)
 142                  */
 143                 lwkt_reltoken(&ilock);
 144                 return (vp);
 145         }
 146         lwkt_reltoken(&ilock);
 147         return (NULLVP);
 148 }
 149
 150 /*
 151  * Insert the hpfsnode into the hash table.
 152  */
 153 void
 154 hpfs_hphashins(struct hpfsnode *hp)
 155 {
 156         struct hphashhead *hpp;
 157         lwkt_tokref ilock;
 158
 159         lwkt_gettoken(&ilock, &hpfs_hphash_token);
 160         hpp = HPNOHASH(hp->h_dev, hp->h_no);
 161         hp->h_flag |= H_HASHED;
 162         LIST_INSERT_HEAD(hpp, hp, h_hash);
 163         lwkt_reltoken(&ilock);
 164 }
 165
 166 /*
 167  * Remove the inode from the hash table.
 168  */
 169 void
 170 hpfs_hphashrem(struct hpfsnode *hp)
 171 {
 172         lwkt_tokref ilock;
 173
 174         lwkt_gettoken(&ilock, &hpfs_hphash_token);
 175         if (hp->h_flag & H_HASHED) {
 176                 hp->h_flag &= ~H_HASHED;
 177                 LIST_REMOVE(hp, h_hash);
 178 #ifdef DIAGNOSTIC
 179                 hp->h_hash.le_next = NULL;
 180                 hp->h_hash.le_prev = NULL;
 181 #endif
 182         }
 183         lwkt_reltoken(&ilock);
 184 }