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 1.10 2004/01/15 20:17:36 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_inittoken(&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 80 lwkt_gettoken(&ufs_ihash_token); 81 for (ip = INOHASH(dev, inum)->lh_first; ip; ip = ip->i_hash.le_next) { 82 if (inum == ip->i_number && dev == ip->i_dev) 83 break; 84 } 85 lwkt_reltoken(&ufs_ihash_token); 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 * Any time we potentially block we must regenerate the token using 97 * lwkt_gentoken(), which at the same time checks the generation number 98 * indicating whether another entity stole the token while we were blocked. 99 * In the best case lwkt_gentoken(). The code below is probably overkill, 100 * but it is particularly important to check the generation number after 101 * acquiring the vnode lock to ensure that the inode association is still 102 * valid. 103 */ 104 struct vnode * 105 ufs_ihashget(dev_t dev, ino_t inum) 106 { 107 struct thread *td = curthread; /* XXX */ 108 struct inode *ip; 109 struct vnode *vp; 110 int gen; 111 112 gen = lwkt_gettoken(&ufs_ihash_token); 113 loop: 114 for (ip = INOHASH(dev, inum)->lh_first; ip; ip = ip->i_hash.le_next) { 115 if (inum == ip->i_number && dev == ip->i_dev) { 116 vp = ITOV(ip); 117 vhold(vp); 118 lwkt_gettoken(&vp->v_interlock); 119 if (lwkt_gentoken(&ufs_ihash_token, &gen) != 0) { 120 lwkt_reltoken(&vp->v_interlock); 121 vdrop(vp); 122 goto loop; 123 } 124 if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK, td)) { 125 vdrop(vp); 126 lwkt_gentoken(&ufs_ihash_token, &gen); 127 goto loop; 128 } 129 if (lwkt_reltoken(&ufs_ihash_token) != gen) { 130 vdrop(vp); 131 vput(vp); 132 gen = lwkt_gettoken(&ufs_ihash_token); 133 goto loop; 134 } 135 vdrop(vp); 136 return (vp); 137 } 138 } 139 lwkt_reltoken(&ufs_ihash_token); 140 return (NULL); 141 } 142 143 /* 144 * Insert the inode into the hash table, and return it locked. 145 */ 146 void 147 ufs_ihashins(struct inode *ip) 148 { 149 struct thread *td = curthread; /* XXX */ 150 struct ihashhead *ipp; 151 152 /* lock the inode, then put it on the appropriate hash list */ 153 lockmgr(&ip->i_lock, LK_EXCLUSIVE, NULL, td); 154 155 lwkt_gettoken(&ufs_ihash_token); 156 ipp = INOHASH(ip->i_dev, ip->i_number); 157 LIST_INSERT_HEAD(ipp, ip, i_hash); 158 ip->i_flag |= IN_HASHED; 159 lwkt_reltoken(&ufs_ihash_token); 160 } 161 162 /* 163 * Remove the inode from the hash table. 164 */ 165 void 166 ufs_ihashrem(ip) 167 struct inode *ip; 168 { 169 lwkt_gettoken(&ufs_ihash_token); 170 if (ip->i_flag & IN_HASHED) { 171 ip->i_flag &= ~IN_HASHED; 172 LIST_REMOVE(ip, i_hash); 173 #ifdef DIAGNOSTIC 174 ip->i_hash.le_next = NULL; 175 ip->i_hash.le_prev = NULL; 176 #endif 177 } 178 lwkt_reltoken(&ufs_ihash_token); 179 } 180