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. 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/ufs/ufs/ufs_ihash.c,v 1.20 1999/08/28 00:52:29 peter Exp $
  35  * $DragonFly: src/sys/vfs/ufs/ufs_ihash.c,v 1.20 2006/10/14 16:26:40 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/malloc.h>
  44 #include <sys/proc.h>
  45
  46 #include "quota.h"
  47 #include "inode.h"
  48 #include "ufs_extern.h"
  49
  50 static MALLOC_DEFINE(M_UFSIHASH, "UFS ihash", "UFS Inode hash tables");
  51 /*
  52  * Structures associated with inode cacheing.
  53  */
  54 static struct inode **ihashtbl;
  55 static u_long   ihash;          /* size of hash table - 1 */
  56 static struct lwkt_token ufs_ihash_token;
  57
  58 #define INOHASH(device, inum)   (&ihashtbl[(minor(device) + (inum)) & ihash])
  59
  60 /*
  61  * Initialize inode hash table.
  62  */
  63 void
  64 ufs_ihashinit(void)
  65 {
  66         ihash = 16;
  67         while (ihash < desiredvnodes)
  68                 ihash <<= 1;
  69         ihashtbl = kmalloc(sizeof(void *) * ihash, M_UFSIHASH, M_WAITOK|M_ZERO);
  70         --ihash;
  71         lwkt_token_init(&ufs_ihash_token);
  72 }
  73
  74 int
  75 ufs_uninit(struct vfsconf *vfc)
  76 {
  77     lwkt_tokref ilock;
  78
  79     lwkt_gettoken(&ilock, &ufs_ihash_token);
  80     if (ihashtbl)
  81                 kfree(ihashtbl, M_UFSIHASH);
  82     lwkt_reltoken(&ilock);
  83
  84     return (0);
  85 }
  86 /*
  87  * Use the device/inum pair to find the incore inode, and return a pointer
  88  * to it. If it is in core, return it, even if it is locked.
  89  */
  90 struct vnode *
  91 ufs_ihashlookup(cdev_t dev, ino_t inum)
  92 {
  93         struct inode *ip;
  94         lwkt_tokref ilock;
  95
  96         lwkt_gettoken(&ilock, &ufs_ihash_token);
  97         for (ip = *INOHASH(dev, inum); ip; ip = ip->i_next) {
  98                 if (inum == ip->i_number && dev == ip->i_dev)
  99                         break;
 100         }
 101         lwkt_reltoken(&ilock);
 102         if (ip)
 103                 return (ITOV(ip));
 104         return (NULLVP);
 105 }
 106
 107 /*
 108  * Use the device/inum pair to find the incore inode, and return a pointer
 109  * to it. If it is in core, but locked, wait for it.
 110  *
 111  * Note that the serializing tokens do not prevent other processes from
 112  * playing with the data structure being protected while we are blocked.
 113  * They do protect us from preemptive interrupts which might try to
 114  * play with the protected data structure.
 115  */
 116 struct vnode *
 117 ufs_ihashget(cdev_t dev, ino_t inum)
 118 {
 119         lwkt_tokref ilock;
 120         struct inode *ip;
 121         struct vnode *vp;
 122
 123         lwkt_gettoken(&ilock, &ufs_ihash_token);
 124 loop:
 125         for (ip = *INOHASH(dev, inum); ip; ip = ip->i_next) {
 126                 if (inum != ip->i_number || dev != ip->i_dev)
 127                         continue;
 128                 vp = ITOV(ip);
 129                 if (vget(vp, LK_EXCLUSIVE))
 130                         goto loop;
 131                 /*
 132                  * We must check to see if the inode has been ripped
 133                  * out from under us after blocking.
 134                  */
 135                 for (ip = *INOHASH(dev, inum); ip; ip = ip->i_next) {
 136                         if (inum == ip->i_number && dev == ip->i_dev)
 137                                 break;
 138                 }
 139                 if (ip == NULL || ITOV(ip) != vp) {
 140                         vput(vp);
 141                         goto loop;
 142                 }
 143                 lwkt_reltoken(&ilock);
 144                 return (vp);
 145         }
 146         lwkt_reltoken(&ilock);
 147         return (NULL);
 148 }
 149
 150 /*
 151  * Check to see if an inode is in the hash table.  This is used to interlock
 152  * file free operations to ensure that the vnode is not reused due to a
 153  * reallocate of its inode number before we have had a chance to recycle it.
 154  */
 155 int
 156 ufs_ihashcheck(cdev_t dev, ino_t inum)
 157 {
 158         lwkt_tokref ilock;
 159         struct inode *ip;
 160
 161         lwkt_gettoken(&ilock, &ufs_ihash_token);
 162         for (ip = *INOHASH(dev, inum); ip; ip = ip->i_next) {
 163                 if (inum == ip->i_number && dev == ip->i_dev)
 164                         break;
 165         }
 166         lwkt_reltoken(&ilock);
 167         return(ip ? 1 : 0);
 168 }
 169
 170 /*
 171  * Insert the inode into the hash table, and return it locked.
 172  */
 173 int
 174 ufs_ihashins(struct inode *ip)
 175 {
 176         struct inode **ipp;
 177         struct inode *iq;
 178         lwkt_tokref ilock;
 179
 180         KKASSERT((ip->i_flag & IN_HASHED) == 0);
 181         lwkt_gettoken(&ilock, &ufs_ihash_token);
 182         ipp = INOHASH(ip->i_dev, ip->i_number);
 183         while ((iq = *ipp) != NULL) {
 184                 if (ip->i_dev == iq->i_dev && ip->i_number == iq->i_number) {
 185                         lwkt_reltoken(&ilock);
 186                         return(EBUSY);
 187                 }
 188                 ipp = &iq->i_next;
 189         }
 190         ip->i_next = NULL;
 191         *ipp = ip;
 192         ip->i_flag |= IN_HASHED;
 193         lwkt_reltoken(&ilock);
 194         return(0);
 195 }
 196
 197 /*
 198  * Remove the inode from the hash table.
 199  */
 200 void
 201 ufs_ihashrem(struct inode *ip)
 202 {
 203         lwkt_tokref ilock;
 204         struct inode **ipp;
 205         struct inode *iq;
 206
 207         lwkt_gettoken(&ilock, &ufs_ihash_token);
 208         if (ip->i_flag & IN_HASHED) {
 209                 ipp = INOHASH(ip->i_dev, ip->i_number);
 210                 while ((iq = *ipp) != NULL) {
 211                         if (ip == iq)
 212                                 break;
 213                         ipp = &iq->i_next;
 214                 }
 215                 KKASSERT(ip == iq);
 216                 *ipp = ip->i_next;
 217                 ip->i_next = NULL;
 218                 ip->i_flag &= ~IN_HASHED;
 219         }
 220         lwkt_reltoken(&ilock);
 221 }
 222