sys/vfs/ufs/ufs_ihash.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/ufs/ufs/ufs_ihash.c,v 1.20 1999/08/28 00:52:29 peter 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/malloc.h>
  39 #include <sys/proc.h>
  40 #include <sys/mount.h>
  41
  42 #include "quota.h"
  43 #include "inode.h"
  44 #include "ufs_extern.h"
  45 #include "ufsmount.h"
  46
  47 static MALLOC_DEFINE(M_UFSIHASH, "UFS ihash", "UFS Inode hash tables");
  48
  49 #define INOHASH(ump, inum)      \
  50         (&ump->um_ihashtbl[inum & ump->um_ihash])
  51
  52 /*
  53  * Initialize inode hash table.
  54  */
  55 void
  56 ufs_ihashinit(struct ufsmount *ump)
  57 {
  58         u_long target = desiredvnodes / 4 + 1;
  59
  60         ump->um_ihash = 16;
  61         while (ump->um_ihash < target)
  62                 ump->um_ihash <<= 1;
  63         ump->um_ihashtbl = kmalloc(sizeof(void *) * ump->um_ihash, M_UFSIHASH,
  64                                    M_WAITOK|M_ZERO);
  65         --ump->um_ihash;
  66 }
  67
  68 void
  69 ufs_ihashuninit(struct ufsmount *ump)
  70 {
  71         if (ump->um_ihashtbl) {
  72                 kfree(ump->um_ihashtbl, M_UFSIHASH);
  73                 ump->um_ihashtbl = NULL;
  74         }
  75 }
  76
  77 /*
  78  * Use the device/inum pair to find the incore inode, and return a pointer
  79  * to it. If it is in core, return it, even if it is locked.
  80  */
  81 struct vnode *
  82 ufs_ihashlookup(struct ufsmount *ump, cdev_t dev, ino_t inum)
  83 {
  84         struct inode *ip = NULL;
  85
  86         for (ip = *INOHASH(ump, inum); ip; ip = ip->i_next) {
  87                 if (inum == ip->i_number && dev == ip->i_dev)
  88                         break;
  89         }
  90         if (ip)
  91                 return (ITOV(ip));
  92         return (NULLVP);
  93 }
  94
  95 /*
  96  * Use the device/inum pair to find the incore inode, and return a pointer
  97  * to it. If it is in core, but locked, wait for it.
  98  *
  99  * This subroutine may block.
 100  */
 101 struct vnode *
 102 ufs_ihashget(struct ufsmount *ump, cdev_t dev, ino_t inum)
 103 {
 104         struct inode *ip;
 105         struct vnode *vp;
 106
 107 loop:
 108         for (ip = *INOHASH(ump, inum); ip; ip = ip->i_next) {
 109                 if (inum != ip->i_number || dev != ip->i_dev)
 110                         continue;
 111                 vp = ITOV(ip);
 112                 if (vget(vp, LK_EXCLUSIVE))
 113                         goto loop;
 114                 /*
 115                  * We must check to see if the inode has been ripped
 116                  * out from under us after blocking.
 117                  */
 118                 for (ip = *INOHASH(ump, inum); ip; ip = ip->i_next) {
 119                         if (inum == ip->i_number && dev == ip->i_dev)
 120                                 break;
 121                 }
 122                 if (ip == NULL || ITOV(ip) != vp) {
 123                         vput(vp);
 124                         goto loop;
 125                 }
 126                 return (vp);
 127         }
 128         return (NULL);
 129 }
 130
 131 /*
 132  * Check to see if an inode is in the hash table.  This is used to interlock
 133  * file free operations to ensure that the vnode is not reused due to a
 134  * reallocate of its inode number before we have had a chance to recycle it.
 135  */
 136 int
 137 ufs_ihashcheck(struct ufsmount *ump, cdev_t dev, ino_t inum)
 138 {
 139         struct inode *ip;
 140
 141         for (ip = *INOHASH(ump, inum); ip; ip = ip->i_next) {
 142                 if (inum == ip->i_number && dev == ip->i_dev)
 143                         break;
 144         }
 145         return(ip ? 1 : 0);
 146 }
 147
 148 /*
 149  * Insert the inode into the hash table, and return it locked.
 150  */
 151 int
 152 ufs_ihashins(struct ufsmount *ump, struct inode *ip)
 153 {
 154         struct inode **ipp;
 155         struct inode *iq;
 156
 157         KKASSERT((ip->i_flag & IN_HASHED) == 0);
 158         ipp = INOHASH(ump, ip->i_number);
 159         while ((iq = *ipp) != NULL) {
 160                 if (ip->i_dev == iq->i_dev && ip->i_number == iq->i_number) {
 161                         return(EBUSY);
 162                 }
 163                 ipp = &iq->i_next;
 164         }
 165         ip->i_next = NULL;
 166         *ipp = ip;
 167         ip->i_flag |= IN_HASHED;
 168         return(0);
 169 }
 170
 171 /*
 172  * Remove the inode from the hash table.
 173  */
 174 void
 175 ufs_ihashrem(struct ufsmount *ump, struct inode *ip)
 176 {
 177         struct inode **ipp;
 178         struct inode *iq;
 179
 180         if (ip->i_flag & IN_HASHED) {
 181                 ipp = INOHASH(ump, ip->i_number);
 182                 while ((iq = *ipp) != NULL) {
 183                         if (ip == iq)
 184                                 break;
 185                         ipp = &iq->i_next;
 186                 }
 187                 KKASSERT(ip == iq);
 188                 *ipp = ip->i_next;
 189                 ip->i_next = NULL;
 190                 ip->i_flag &= ~IN_HASHED;
 191         }
 192 }
 193