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 1.11 2004/03/01 06:33:23 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 LIST_HEAD(ihashhead, inode) *ihashtbl; 55 static u_long ihash; /* size of hash table - 1 */ 56 #define INOHASH(device, inum) (&ihashtbl[(minor(device) + (inum)) & ihash]) 57 static struct lwkt_token ufs_ihash_token; 58 59 /* 60 * Initialize inode hash table. 61 */ 62 void 63 ufs_ihashinit() 64 { 65 ihashtbl = hashinit(desiredvnodes, M_UFSIHASH, &ihash); 66 lwkt_token_init(&ufs_ihash_token); 67 } 68 69 /* 70 * Use the device/inum pair to find the incore inode, and return a pointer 71 * to it. If it is in core, return it, even if it is locked. 72 */ 73 struct vnode * 74 ufs_ihashlookup(dev, inum) 75 dev_t dev; 76 ino_t inum; 77 { 78 struct inode *ip; 79 lwkt_tokref ilock; 80 81 lwkt_gettoken(&ilock, &ufs_ihash_token); 82 for (ip = INOHASH(dev, inum)->lh_first; ip; ip = ip->i_hash.le_next) { 83 if (inum == ip->i_number && dev == ip->i_dev) 84 break; 85 } 86 lwkt_reltoken(&ilock); 87 88 if (ip) 89 return (ITOV(ip)); 90 return (NULLVP); 91 } 92 93 /* 94 * Use the device/inum pair to find the incore inode, and return a pointer 95 * to it. If it is in core, but locked, wait for it. 96 * 97 * Note that the serializing tokens do not prevent other processes from 98 * playing with the data structure being protected while we are blocked. 99 * They do protect us from preemptive interrupts which might try to 100 * play with the protected data structure. 101 */ 102 struct vnode * 103 ufs_ihashget(dev_t dev, ino_t inum) 104 { 105 struct thread *td = curthread; /* XXX */ 106 lwkt_tokref ilock; 107 lwkt_tokref vlock; 108 struct inode *ip; 109 struct vnode *vp; 110 111 lwkt_gettoken(&ilock, &ufs_ihash_token); 112 loop: 113 for (ip = INOHASH(dev, inum)->lh_first; ip; ip = ip->i_hash.le_next) { 114 if (inum != ip->i_number || dev != ip->i_dev) 115 continue; 116 vp = ITOV(ip); 117 lwkt_gettoken(&vlock, vp->v_interlock); 118 /* 119 * We must check to see if the inode has been ripped 120 * out from under us after blocking. 121 */ 122 for (ip = INOHASH(dev, inum)->lh_first; ip; ip = ip->i_hash.le_next) { 123 if (inum == ip->i_number && dev == ip->i_dev) 124 break; 125 } 126 if (ip == NULL || ITOV(ip) != vp) { 127 lwkt_reltoken(&vlock); 128 goto loop; 129 } 130 if (vget(vp, &vlock, LK_EXCLUSIVE | LK_INTERLOCK, td)) 131 goto loop; 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 void 143 ufs_ihashins(struct inode *ip) 144 { 145 struct thread *td = curthread; /* XXX */ 146 struct ihashhead *ipp; 147 lwkt_tokref ilock; 148 149 /* lock the inode, then put it on the appropriate hash list */ 150 lockmgr(&ip->i_lock, LK_EXCLUSIVE, NULL, td); 151 152 lwkt_gettoken(&ilock, &ufs_ihash_token); 153 ipp = INOHASH(ip->i_dev, ip->i_number); 154 LIST_INSERT_HEAD(ipp, ip, i_hash); 155 ip->i_flag |= IN_HASHED; 156 lwkt_reltoken(&ilock); 157 } 158 159 /* 160 * Remove the inode from the hash table. 161 */ 162 void 163 ufs_ihashrem(ip) 164 struct inode *ip; 165 { 166 lwkt_tokref ilock; 167 168 lwkt_gettoken(&ilock, &ufs_ihash_token); 169 if (ip->i_flag & IN_HASHED) { 170 ip->i_flag &= ~IN_HASHED; 171 LIST_REMOVE(ip, i_hash); 172 #ifdef DIAGNOSTIC 173 ip->i_hash.le_next = NULL; 174 ip->i_hash.le_prev = NULL; 175 #endif 176 } 177 lwkt_reltoken(&ilock); 178 } 179