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 1.14 2004/10/12 19:21:12 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 = malloc(sizeof(void *) * ihash, M_UFSIHASH, M_WAITOK|M_ZERO); 70 --ihash; 71 lwkt_token_init(&ufs_ihash_token); 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(dev_t dev, ino_t inum) 80 { 81 struct inode *ip; 82 lwkt_tokref ilock; 83 84 lwkt_gettoken(&ilock, &ufs_ihash_token); 85 for (ip = *INOHASH(dev, inum); ip; ip = ip->i_next) { 86 if (inum == ip->i_number && dev == ip->i_dev) 87 break; 88 } 89 lwkt_reltoken(&ilock); 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 * Note that the serializing tokens do not prevent other processes from 100 * playing with the data structure being protected while we are blocked. 101 * They do protect us from preemptive interrupts which might try to 102 * play with the protected data structure. 103 */ 104 struct vnode * 105 ufs_ihashget(dev_t dev, ino_t inum) 106 { 107 struct thread *td = curthread; /* XXX */ 108 lwkt_tokref ilock; 109 struct inode *ip; 110 struct vnode *vp; 111 112 lwkt_gettoken(&ilock, &ufs_ihash_token); 113 loop: 114 for (ip = *INOHASH(dev, inum); ip; ip = ip->i_next) { 115 if (inum != ip->i_number || dev != ip->i_dev) 116 continue; 117 vp = ITOV(ip); 118 if (vget(vp, LK_EXCLUSIVE, td)) 119 goto loop; 120 /* 121 * We must check to see if the inode has been ripped 122 * out from under us after blocking. 123 */ 124 for (ip = *INOHASH(dev, inum); ip; ip = ip->i_next) { 125 if (inum == ip->i_number && dev == ip->i_dev) 126 break; 127 } 128 if (ip == NULL || ITOV(ip) != vp) { 129 vput(vp); 130 goto loop; 131 } 132 lwkt_reltoken(&ilock); 133 return (vp); 134 } 135 lwkt_reltoken(&ilock); 136 return (NULL); 137 } 138 139 /* 140 * Insert the inode into the hash table, and return it locked. 141 */ 142 int 143 ufs_ihashins(struct inode *ip) 144 { 145 struct inode **ipp; 146 struct inode *iq; 147 lwkt_tokref ilock; 148 149 KKASSERT((ip->i_flag & IN_HASHED) == 0); 150 lwkt_gettoken(&ilock, &ufs_ihash_token); 151 ipp = INOHASH(ip->i_dev, ip->i_number); 152 while ((iq = *ipp) != NULL) { 153 if (ip->i_dev == iq->i_dev && ip->i_number == iq->i_number) { 154 lwkt_reltoken(&ilock); 155 return(EBUSY); 156 } 157 ipp = &iq->i_next; 158 } 159 ip->i_next = NULL; 160 *ipp = ip; 161 ip->i_flag |= IN_HASHED; 162 lwkt_reltoken(&ilock); 163 return(0); 164 } 165 166 /* 167 * Remove the inode from the hash table. 168 */ 169 void 170 ufs_ihashrem(struct inode *ip) 171 { 172 lwkt_tokref ilock; 173 struct inode **ipp; 174 struct inode *iq; 175 176 lwkt_gettoken(&ilock, &ufs_ihash_token); 177 if (ip->i_flag & IN_HASHED) { 178 ipp = INOHASH(ip->i_dev, 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 lwkt_reltoken(&ilock); 190 } 191 192