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, "ufsihash"); 72 } 73 74 int 75 ufs_uninit(struct vfsconf *vfc) 76 { 77 lwkt_gettoken(&ufs_ihash_token); 78 if (ihashtbl) 79 kfree(ihashtbl, M_UFSIHASH); 80 lwkt_reltoken(&ufs_ihash_token); 81 82 return (0); 83 } 84 /* 85 * Use the device/inum pair to find the incore inode, and return a pointer 86 * to it. If it is in core, return it, even if it is locked. 87 */ 88 struct vnode * 89 ufs_ihashlookup(cdev_t dev, ino_t inum) 90 { 91 struct inode *ip; 92 93 lwkt_gettoken(&ufs_ihash_token); 94 for (ip = *INOHASH(dev, inum); ip; ip = ip->i_next) { 95 if (inum == ip->i_number && dev == ip->i_dev) 96 break; 97 } 98 lwkt_reltoken(&ufs_ihash_token); 99 if (ip) 100 return (ITOV(ip)); 101 return (NULLVP); 102 } 103 104 /* 105 * Use the device/inum pair to find the incore inode, and return a pointer 106 * to it. If it is in core, but locked, wait for it. 107 * 108 * Note that the serializing tokens do not prevent other processes from 109 * playing with the data structure being protected while we are blocked. 110 * They do protect us from preemptive interrupts which might try to 111 * play with the protected data structure. 112 */ 113 struct vnode * 114 ufs_ihashget(cdev_t dev, ino_t inum) 115 { 116 struct inode *ip; 117 struct vnode *vp; 118 119 lwkt_gettoken(&ufs_ihash_token); 120 loop: 121 for (ip = *INOHASH(dev, inum); ip; ip = ip->i_next) { 122 if (inum != ip->i_number || dev != ip->i_dev) 123 continue; 124 vp = ITOV(ip); 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 (ip = *INOHASH(dev, inum); ip; ip = ip->i_next) { 132 if (inum == ip->i_number && dev == ip->i_dev) 133 break; 134 } 135 if (ip == NULL || ITOV(ip) != vp) { 136 vput(vp); 137 goto loop; 138 } 139 lwkt_reltoken(&ufs_ihash_token); 140 return (vp); 141 } 142 lwkt_reltoken(&ufs_ihash_token); 143 return (NULL); 144 } 145 146 /* 147 * Check to see if an inode is in the hash table. This is used to interlock 148 * file free operations to ensure that the vnode is not reused due to a 149 * reallocate of its inode number before we have had a chance to recycle it. 150 */ 151 int 152 ufs_ihashcheck(cdev_t dev, ino_t inum) 153 { 154 struct inode *ip; 155 156 lwkt_gettoken(&ufs_ihash_token); 157 for (ip = *INOHASH(dev, inum); ip; ip = ip->i_next) { 158 if (inum == ip->i_number && dev == ip->i_dev) 159 break; 160 } 161 lwkt_reltoken(&ufs_ihash_token); 162 return(ip ? 1 : 0); 163 } 164 165 /* 166 * Insert the inode into the hash table, and return it locked. 167 */ 168 int 169 ufs_ihashins(struct inode *ip) 170 { 171 struct inode **ipp; 172 struct inode *iq; 173 174 KKASSERT((ip->i_flag & IN_HASHED) == 0); 175 lwkt_gettoken(&ufs_ihash_token); 176 ipp = INOHASH(ip->i_dev, ip->i_number); 177 while ((iq = *ipp) != NULL) { 178 if (ip->i_dev == iq->i_dev && ip->i_number == iq->i_number) { 179 lwkt_reltoken(&ufs_ihash_token); 180 return(EBUSY); 181 } 182 ipp = &iq->i_next; 183 } 184 ip->i_next = NULL; 185 *ipp = ip; 186 ip->i_flag |= IN_HASHED; 187 lwkt_reltoken(&ufs_ihash_token); 188 return(0); 189 } 190 191 /* 192 * Remove the inode from the hash table. 193 */ 194 void 195 ufs_ihashrem(struct inode *ip) 196 { 197 struct inode **ipp; 198 struct inode *iq; 199 200 lwkt_gettoken(&ufs_ihash_token); 201 if (ip->i_flag & IN_HASHED) { 202 ipp = INOHASH(ip->i_dev, ip->i_number); 203 while ((iq = *ipp) != NULL) { 204 if (ip == iq) 205 break; 206 ipp = &iq->i_next; 207 } 208 KKASSERT(ip == iq); 209 *ipp = ip->i_next; 210 ip->i_next = NULL; 211 ip->i_flag &= ~IN_HASHED; 212 } 213 lwkt_reltoken(&ufs_ihash_token); 214 } 215 216