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. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * @(#)ufs_ihash.c 8.7 (Berkeley) 5/17/95 30 * $FreeBSD: src/sys/ufs/ufs/ufs_ihash.c,v 1.20 1999/08/28 00:52:29 peter Exp $ 31 */ 32 33 #include <sys/param.h> 34 #include <sys/systm.h> 35 #include <sys/kernel.h> 36 #include <sys/lock.h> 37 #include <sys/vnode.h> 38 #include <sys/malloc.h> 39 #include <sys/proc.h> 40 41 #include <vfs/ext2fs/fs.h> 42 #include <vfs/ext2fs/ext2fs.h> 43 #include <vfs/ext2fs/inode.h> 44 #include <vfs/ext2fs/ext2_dinode.h> 45 #include <vfs/ext2fs/ext2_extern.h> 46 47 static MALLOC_DEFINE(M_EXT2IHASH, "EXT2 ihash", "EXT2 Inode hash tables"); 48 /* 49 * Structures associated with inode cacheing. 50 */ 51 static struct inode **ext2_ihashtbl; 52 static u_long ext2_ihash; /* size of hash table - 1 */ 53 static struct lwkt_token ext2_ihash_token; 54 55 #define INOHASH(device, inum) (&ext2_ihashtbl[(minor(device) + (inum)) & ext2_ihash]) 56 57 /* 58 * Initialize inode hash table. 59 */ 60 void 61 ext2_ihashinit(void) 62 { 63 ext2_ihash = vfs_inodehashsize(); 64 ext2_ihashtbl = malloc(sizeof(void *) * ext2_ihash, M_EXT2IHASH, 65 M_WAITOK | M_ZERO); 66 --ext2_ihash; 67 lwkt_token_init(&ext2_ihash_token, "ext2ihash"); 68 } 69 70 void 71 ext2_ihashuninit(void) 72 { 73 lwkt_gettoken(&ext2_ihash_token); 74 if (ext2_ihashtbl) 75 free(ext2_ihashtbl, M_EXT2IHASH); 76 lwkt_reltoken(&ext2_ihash_token); 77 } 78 79 /* 80 * Use the device/inum pair to find the incore inode, and return a pointer 81 * to it. If it is in core, but locked, wait for it. 82 * 83 * Note that the serializing tokens do not prevent other processes from 84 * playing with the data structure being protected while we are blocked. 85 * They do protect us from preemptive interrupts which might try to 86 * play with the protected data structure. 87 */ 88 struct vnode * 89 ext2_ihashget(cdev_t dev, ino_t inum) 90 { 91 struct inode *ip; 92 struct vnode *vp; 93 94 lwkt_gettoken(&ext2_ihash_token); 95 loop: 96 for (ip = *INOHASH(dev, inum); ip; ip = ip->i_next) { 97 if (inum != ip->i_number || dev != ip->i_dev) 98 continue; 99 vp = ITOV(ip); 100 if (vget(vp, LK_EXCLUSIVE)) 101 goto loop; 102 /* 103 * We must check to see if the inode has been ripped 104 * out from under us after blocking. 105 */ 106 for (ip = *INOHASH(dev, inum); ip; ip = ip->i_next) { 107 if (inum == ip->i_number && dev == ip->i_dev) 108 break; 109 } 110 if (ip == NULL || ITOV(ip) != vp) { 111 vput(vp); 112 goto loop; 113 } 114 lwkt_reltoken(&ext2_ihash_token); 115 return (vp); 116 } 117 lwkt_reltoken(&ext2_ihash_token); 118 return (NULL); 119 } 120 121 /* 122 * Insert the inode into the hash table, and return it locked. 123 */ 124 int 125 ext2_ihashins(struct inode *ip) 126 { 127 struct inode **ipp; 128 struct inode *iq; 129 130 KKASSERT((ip->i_flag & IN_HASHED) == 0); 131 lwkt_gettoken(&ext2_ihash_token); 132 ipp = INOHASH(ip->i_dev, ip->i_number); 133 while ((iq = *ipp) != NULL) { 134 if (ip->i_dev == iq->i_dev && ip->i_number == iq->i_number) { 135 lwkt_reltoken(&ext2_ihash_token); 136 return (EBUSY); 137 } 138 ipp = &iq->i_next; 139 } 140 ip->i_next = NULL; 141 *ipp = ip; 142 ip->i_flag |= IN_HASHED; 143 lwkt_reltoken(&ext2_ihash_token); 144 return (0); 145 } 146 147 /* 148 * Remove the inode from the hash table. 149 */ 150 void 151 ext2_ihashrem(struct inode *ip) 152 { 153 struct inode **ipp; 154 struct inode *iq; 155 156 lwkt_gettoken(&ext2_ihash_token); 157 if (ip->i_flag & IN_HASHED) { 158 ipp = INOHASH(ip->i_dev, ip->i_number); 159 while ((iq = *ipp) != NULL) { 160 if (ip == iq) 161 break; 162 ipp = &iq->i_next; 163 } 164 KKASSERT(ip == iq); 165 *ipp = ip->i_next; 166 ip->i_next = NULL; 167 ip->i_flag &= ~IN_HASHED; 168 } 169 lwkt_reltoken(&ext2_ihash_token); 170 } 171