1/*- 2 * Copyright (c) 2005 Poul-Henning Kamp 3 * 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 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 */ 27 28#include <sys/cdefs.h> 29__FBSDID("$FreeBSD$"); 30 31#include <sys/param.h> 32#include <sys/systm.h> 33#include <sys/kernel.h> 34#include <sys/malloc.h> 35#include <sys/mount.h> 36#include <sys/vnode.h> 37 38static MALLOC_DEFINE(M_VFS_HASH, "vfs_hash", "VFS hash table"); 39 40static LIST_HEAD(vfs_hash_head, vnode) *vfs_hash_tbl; 41static LIST_HEAD(,vnode) vfs_hash_side; 42static u_long vfs_hash_mask; 43static struct mtx vfs_hash_mtx; 44 45static void 46vfs_hashinit(void *dummy __unused) 47{ 48 49 vfs_hash_tbl = hashinit(desiredvnodes, M_VFS_HASH, &vfs_hash_mask); 50 mtx_init(&vfs_hash_mtx, "vfs hash", NULL, MTX_DEF); 51 LIST_INIT(&vfs_hash_side); 52} 53 54/* Must be SI_ORDER_SECOND so desiredvnodes is available */ 55SYSINIT(vfs_hash, SI_SUB_VFS, SI_ORDER_SECOND, vfs_hashinit, NULL); 56 57u_int 58vfs_hash_index(struct vnode *vp) 59{ 60 61 return (vp->v_hash + vp->v_mount->mnt_hashseed); 62} 63 64static struct vfs_hash_head * 65vfs_hash_bucket(const struct mount *mp, u_int hash) 66{ 67 68 return (&vfs_hash_tbl[(hash + mp->mnt_hashseed) & vfs_hash_mask]); 69} 70 71int 72vfs_hash_get(const struct mount *mp, u_int hash, int flags, struct thread *td, 73 struct vnode **vpp, vfs_hash_cmp_t *fn, void *arg) 74{ 75 struct vnode *vp; 76 int error; 77 78 while (1) { 79 mtx_lock(&vfs_hash_mtx); 80 LIST_FOREACH(vp, vfs_hash_bucket(mp, hash), v_hashlist) { 81 if (vp->v_hash != hash) 82 continue; 83 if (vp->v_mount != mp) 84 continue; 85 if (fn != NULL && fn(vp, arg)) 86 continue; 87 VI_LOCK(vp); 88 mtx_unlock(&vfs_hash_mtx); 89 error = vget(vp, flags | LK_INTERLOCK, td); 90 if (error == ENOENT && (flags & LK_NOWAIT) == 0) 91 break; 92 if (error) 93 return (error); 94 *vpp = vp; 95 return (0); 96 } 97 if (vp == NULL) { 98 mtx_unlock(&vfs_hash_mtx); 99 *vpp = NULL; 100 return (0); 101 } 102 } 103} 104 105void 106vfs_hash_ref(const struct mount *mp, u_int hash, struct thread *td, 107 struct vnode **vpp, vfs_hash_cmp_t *fn, void *arg) 108{ 109 struct vnode *vp; 110 111 while (1) { 112 mtx_lock(&vfs_hash_mtx); 113 LIST_FOREACH(vp, vfs_hash_bucket(mp, hash), v_hashlist) { 114 if (vp->v_hash != hash) 115 continue; 116 if (vp->v_mount != mp) 117 continue; 118 if (fn != NULL && fn(vp, arg)) 119 continue; 120 vhold(vp); 121 mtx_unlock(&vfs_hash_mtx); 122 vref(vp); 123 vdrop(vp); 124 *vpp = vp; 125 return; 126 } 127 if (vp == NULL) { 128 mtx_unlock(&vfs_hash_mtx); 129 *vpp = NULL; 130 return; 131 } 132 } 133} 134 135void 136vfs_hash_remove(struct vnode *vp) 137{ 138 139 mtx_lock(&vfs_hash_mtx); 140 LIST_REMOVE(vp, v_hashlist); 141 mtx_unlock(&vfs_hash_mtx); 142} 143 144int 145vfs_hash_insert(struct vnode *vp, u_int hash, int flags, struct thread *td, 146 struct vnode **vpp, vfs_hash_cmp_t *fn, void *arg) 147{ 148 struct vnode *vp2; 149 int error; 150 151 *vpp = NULL; 152 while (1) { 153 mtx_lock(&vfs_hash_mtx); 154 LIST_FOREACH(vp2, 155 vfs_hash_bucket(vp->v_mount, hash), v_hashlist) { 156 if (vp2->v_hash != hash) 157 continue; 158 if (vp2->v_mount != vp->v_mount) 159 continue; 160 if (fn != NULL && fn(vp2, arg)) 161 continue; 162 VI_LOCK(vp2); 163 mtx_unlock(&vfs_hash_mtx); 164 error = vget(vp2, flags | LK_INTERLOCK, td); 165 if (error == ENOENT && (flags & LK_NOWAIT) == 0) 166 break; 167 mtx_lock(&vfs_hash_mtx); 168 LIST_INSERT_HEAD(&vfs_hash_side, vp, v_hashlist); 169 mtx_unlock(&vfs_hash_mtx); 170 vput(vp); 171 if (!error) 172 *vpp = vp2; 173 return (error); 174 } 175 if (vp2 == NULL) 176 break; 177 178 } 179 vp->v_hash = hash; 180 LIST_INSERT_HEAD(vfs_hash_bucket(vp->v_mount, hash), vp, v_hashlist); 181 mtx_unlock(&vfs_hash_mtx); 182 return (0); 183} 184 185void 186vfs_hash_rehash(struct vnode *vp, u_int hash) 187{ 188 189 mtx_lock(&vfs_hash_mtx); 190 LIST_REMOVE(vp, v_hashlist); 191 LIST_INSERT_HEAD(vfs_hash_bucket(vp->v_mount, hash), vp, v_hashlist); 192 vp->v_hash = hash; 193 mtx_unlock(&vfs_hash_mtx); 194} 195 196void 197vfs_hash_changesize(int newmaxvnodes) 198{ 199 struct vfs_hash_head *vfs_hash_newtbl, *vfs_hash_oldtbl; 200 u_long vfs_hash_newmask, vfs_hash_oldmask; 201 struct vnode *vp; 202 int i; 203 204 vfs_hash_newtbl = hashinit(newmaxvnodes, M_VFS_HASH, 205 &vfs_hash_newmask); 206 /* If same hash table size, nothing to do */ 207 if (vfs_hash_mask == vfs_hash_newmask) { 208 free(vfs_hash_newtbl, M_VFS_HASH); 209 return; 210 } 211 /* 212 * Move everything from the old hash table to the new table. 213 * None of the vnodes in the table can be recycled because to 214 * do so, they have to be removed from the hash table. 215 */ 216 mtx_lock(&vfs_hash_mtx); 217 vfs_hash_oldtbl = vfs_hash_tbl; 218 vfs_hash_oldmask = vfs_hash_mask; 219 vfs_hash_tbl = vfs_hash_newtbl; 220 vfs_hash_mask = vfs_hash_newmask; 221 for (i = 0; i <= vfs_hash_oldmask; i++) { 222 while ((vp = LIST_FIRST(&vfs_hash_oldtbl[i])) != NULL) { 223 LIST_REMOVE(vp, v_hashlist); 224 LIST_INSERT_HEAD( 225 vfs_hash_bucket(vp->v_mount, vp->v_hash), 226 vp, v_hashlist); 227 } 228 } 229 mtx_unlock(&vfs_hash_mtx); 230 free(vfs_hash_oldtbl, M_VFS_HASH); 231} 232