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