vfs_hash.c revision 143663
1143561Sphk/*- 2143561Sphk * Copyright (c) 2005 Poul-Henning Kamp 3143561Sphk * All rights reserved. 4143561Sphk * 5143561Sphk * Redistribution and use in source and binary forms, with or without 6143561Sphk * modification, are permitted provided that the following conditions 7143561Sphk * are met: 8143561Sphk * 1. Redistributions of source code must retain the above copyright 9143561Sphk * notice, this list of conditions and the following disclaimer. 10143561Sphk * 2. Redistributions in binary form must reproduce the above copyright 11143561Sphk * notice, this list of conditions and the following disclaimer in the 12143561Sphk * documentation and/or other materials provided with the distribution. 13143561Sphk * 14143561Sphk * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15143561Sphk * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16143561Sphk * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17143561Sphk * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18143561Sphk * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19143561Sphk * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20143561Sphk * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21143561Sphk * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22143561Sphk * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23143561Sphk * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24143561Sphk * SUCH DAMAGE. 25143561Sphk * 26143561Sphk */ 27143561Sphk 28143561Sphk#include <sys/cdefs.h> 29143561Sphk__FBSDID("$FreeBSD: head/sys/kern/vfs_hash.c 143663 2005-03-15 20:00:03Z phk $"); 30143561Sphk 31143561Sphk#include <sys/param.h> 32143561Sphk#include <sys/systm.h> 33143561Sphk#include <sys/kernel.h> 34143561Sphk#include <sys/malloc.h> 35143561Sphk#include <sys/vnode.h> 36143561Sphk 37143561Sphkstatic MALLOC_DEFINE(M_VFS_HASH, "VFS hash", "VFS hash table"); 38143561Sphk 39143561Sphkstatic LIST_HEAD(vfs_hashhead, vnode) *vfs_hash_tbl; 40143561Sphkstatic u_long vfs_hash_mask; 41143561Sphkstatic struct mtx vfs_hash_mtx; 42143561Sphk 43143561Sphkstatic void 44143561Sphkvfs_hashinit(void *dummy __unused) 45143561Sphk{ 46143561Sphk 47143561Sphk vfs_hash_tbl = hashinit(desiredvnodes, M_VFS_HASH, &vfs_hash_mask); 48143561Sphk mtx_init(&vfs_hash_mtx, "vfs hash", NULL, MTX_DEF); 49143561Sphk} 50143561Sphk 51143561Sphk/* Must be SI_ORDER_SECOND so desiredvnodes is available */ 52143561SphkSYSINIT(vfs_hash, SI_SUB_VFS, SI_ORDER_SECOND, vfs_hashinit, NULL) 53143561Sphk 54143561Sphkint 55143561Sphkvfs_hash_get(struct mount *mp, u_int hash, int flags, struct thread *td, struct vnode **vpp) 56143561Sphk{ 57143561Sphk struct vnode *vp; 58143561Sphk int error; 59143561Sphk 60143561Sphk while (1) { 61143561Sphk mtx_lock(&vfs_hash_mtx); 62143561Sphk LIST_FOREACH(vp, 63143561Sphk &vfs_hash_tbl[hash & vfs_hash_mask], v_hashlist) { 64143561Sphk if (vp->v_hash != hash) 65143561Sphk continue; 66143561Sphk if (vp->v_mount != mp) 67143561Sphk continue; 68143561Sphk VI_LOCK(vp); 69143561Sphk mtx_unlock(&vfs_hash_mtx); 70143561Sphk error = vget(vp, flags | LK_INTERLOCK, td); 71143561Sphk if (error == ENOENT) 72143561Sphk break; 73143561Sphk if (error) 74143561Sphk return (error); 75143561Sphk *vpp = vp; 76143561Sphk return (0); 77143561Sphk } 78143561Sphk if (vp == NULL) { 79143561Sphk mtx_unlock(&vfs_hash_mtx); 80143561Sphk *vpp = NULL; 81143561Sphk return (0); 82143561Sphk } 83143561Sphk } 84143561Sphk} 85143561Sphk 86143561Sphkvoid 87143561Sphkvfs_hash_remove(struct vnode *vp) 88143561Sphk{ 89143561Sphk 90143561Sphk mtx_lock(&vfs_hash_mtx); 91143561Sphk VI_LOCK(vp); 92143561Sphk VNASSERT(vp->v_iflag & VI_HASHED, vp, ("vfs_hash_remove: not hashed")); 93143561Sphk LIST_REMOVE(vp, v_hashlist); 94143561Sphk vp->v_iflag &= ~VI_HASHED; 95143561Sphk VI_UNLOCK(vp); 96143561Sphk mtx_unlock(&vfs_hash_mtx); 97143561Sphk} 98143561Sphk 99143561Sphkint 100143561Sphkvfs_hash_insert(struct vnode *vp, u_int hash, int flags, struct thread *td, struct vnode **vpp) 101143561Sphk{ 102143561Sphk struct vnode *vp2; 103143561Sphk int error; 104143561Sphk 105143619Sphk lockmgr(vp->v_vnlock, LK_EXCLUSIVE, NULL, td); 106143619Sphk *vpp = NULL; 107143561Sphk while (1) { 108143561Sphk mtx_lock(&vfs_hash_mtx); 109143561Sphk LIST_FOREACH(vp2, 110143561Sphk &vfs_hash_tbl[hash & vfs_hash_mask], v_hashlist) { 111143561Sphk if (vp2->v_hash != hash) 112143561Sphk continue; 113143561Sphk if (vp2->v_mount != vp->v_mount) 114143561Sphk continue; 115143561Sphk VI_LOCK(vp2); 116143561Sphk mtx_unlock(&vfs_hash_mtx); 117143561Sphk error = vget(vp2, flags | LK_INTERLOCK, td); 118143561Sphk if (error == ENOENT) 119143561Sphk break; 120143663Sphk vput(vp); 121143663Sphk if (!error) 122143663Sphk *vpp = vp2; 123143663Sphk return (error); 124143561Sphk } 125143561Sphk if (vp2 == NULL) 126143561Sphk break; 127143561Sphk 128143561Sphk } 129143561Sphk VI_LOCK(vp); 130143561Sphk VNASSERT(!(vp->v_iflag & VI_HASHED), vp, 131143561Sphk ("vfs_hash_insert: already hashed")); 132143561Sphk vp->v_hash = hash; 133143561Sphk LIST_INSERT_HEAD(&vfs_hash_tbl[hash & vfs_hash_mask], vp, v_hashlist); 134143561Sphk vp->v_iflag |= VI_HASHED; 135143561Sphk VI_UNLOCK(vp); 136143561Sphk mtx_unlock(&vfs_hash_mtx); 137143561Sphk return (0); 138143561Sphk} 139143561Sphk 140143561Sphkvoid 141143561Sphkvfs_hash_rehash(struct vnode *vp, u_int hash) 142143561Sphk{ 143143561Sphk 144143561Sphk mtx_lock(&vfs_hash_mtx); 145143561Sphk VNASSERT(vp->v_iflag & VI_HASHED, vp, ("vfs_hash_rehash: not hashed")); 146143561Sphk LIST_REMOVE(vp, v_hashlist); 147143561Sphk LIST_INSERT_HEAD(&vfs_hash_tbl[hash & vfs_hash_mask], vp, v_hashlist); 148143561Sphk vp->v_hash = hash; 149143561Sphk mtx_unlock(&vfs_hash_mtx); 150143561Sphk} 151