pseudofs_vncache.c revision 77998
1/*- 2 * Copyright (c) 2001 Dag-Erling Co�dan Sm�rgrav 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 * in this position and unchanged. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. The name of the author may not be used to endorse or promote products 15 * derived from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 * 28 * $FreeBSD: head/sys/fs/pseudofs/pseudofs_vncache.c 77998 2001-06-10 18:39:21Z des $ 29 */ 30 31#include <sys/param.h> 32#include <sys/kernel.h> 33#include <sys/systm.h> 34#include <sys/malloc.h> 35#include <sys/mount.h> 36#include <sys/mutex.h> 37#include <sys/sbuf.h> 38#include <sys/sysctl.h> 39#include <sys/vnode.h> 40 41#include <fs/pseudofs/pseudofs.h> 42#include <fs/pseudofs/pseudofs_internal.h> 43 44static MALLOC_DEFINE(M_PFSVNCACHE, "pfs_vncache", "pseudofs vnode cache"); 45 46static struct mtx pfs_vncache_mutex; 47 48struct pfs_vnode { 49 struct vnode *pv_vnode; 50 struct pfs_vnode *pv_next; 51} *pfs_vncache; 52 53SYSCTL_NODE(_vfs_pfs, OID_AUTO, vncache, CTLFLAG_RW, 0, 54 "pseudofs vnode cache"); 55 56static int pfs_vncache_hits; 57SYSCTL_INT(_vfs_pfs_vncache, OID_AUTO, hits, CTLFLAG_RD, &pfs_vncache_hits, 0, 58 "number of cache hits since initialization"); 59 60static int pfs_vncache_misses; 61SYSCTL_INT(_vfs_pfs_vncache, OID_AUTO, misses, CTLFLAG_RD, &pfs_vncache_misses, 0, 62 "number of cache misses since initialization"); 63 64extern vop_t **pfs_vnodeop_p; 65 66/* 67 * Initialize vnode cache 68 */ 69void 70pfs_vncache_load(void) 71{ 72 mtx_init(&pfs_vncache_mutex, "pseudofs_vncache", MTX_DEF); 73} 74 75/* 76 * Tear down vnode cache 77 */ 78void 79pfs_vncache_unload(void) 80{ 81 mtx_destroy(&pfs_vncache_mutex); 82} 83 84/* 85 * Allocate a vnode 86 */ 87int 88pfs_vncache_alloc(struct mount *mp, struct vnode **vpp, 89 struct pfs_node *pn, pid_t pid) 90{ 91 struct pfs_vnode *pv; 92 struct pfs_vdata *pvd; 93 int error; 94 95 /* see if the vnode is in the cache */ 96 mtx_lock(&pfs_vncache_mutex); 97 for (pv = pfs_vncache; pv; pv = pv->pv_next) { 98 pvd = (struct pfs_vdata *)pv->pv_vnode->v_data; 99 if (pvd->pvd_pn == pn && pvd->pvd_pid == pid) { 100 if (vget(pv->pv_vnode, 0, curproc) == 0) { 101 ++pfs_vncache_hits; 102 *vpp = pv->pv_vnode; 103 mtx_unlock(&pfs_vncache_mutex); 104 return (0); 105 } 106 /* XXX if this can happen, we're in trouble */ 107 break; 108 } 109 } 110 mtx_unlock(&pfs_vncache_mutex); 111 ++pfs_vncache_misses; 112 113 /* nope, get a new one */ 114 MALLOC(pv, struct pfs_vnode *, sizeof *pv, M_PFSVNCACHE, M_WAITOK); 115 MALLOC(pvd, struct pfs_vdata *, sizeof *pvd, M_PFSVNCACHE, M_WAITOK); 116 error = getnewvnode(VT_PSEUDOFS, mp, pfs_vnodeop_p, vpp); 117 if (error) 118 return (error); 119 pvd->pvd_pn = pn; 120 pvd->pvd_pid = pid; 121 (*vpp)->v_data = pvd; 122 switch (pn->pn_type) { 123 case pfstype_root: 124 (*vpp)->v_flag = VROOT; 125#if 0 126 printf("root vnode allocated\n"); 127#endif 128 case pfstype_dir: 129 case pfstype_this: 130 case pfstype_parent: 131 case pfstype_procdir: 132 (*vpp)->v_type = VDIR; 133 break; 134 case pfstype_file: 135 (*vpp)->v_type = VREG; 136 break; 137 case pfstype_symlink: 138 (*vpp)->v_type = VLNK; 139 break; 140 case pfstype_none: 141 KASSERT(0, ("pfs_vncache_alloc called for null node\n")); 142 default: 143 panic("%s has unexpected type: %d", pn->pn_name, pn->pn_type); 144 } 145 pv->pv_vnode = *vpp; 146 mtx_lock(&pfs_vncache_mutex); 147 pv->pv_next = pfs_vncache; 148 pfs_vncache = pv; 149 mtx_unlock(&pfs_vncache_mutex); 150 return (0); 151} 152 153/* 154 * Free a vnode 155 */ 156int 157pfs_vncache_free(struct vnode *vp) 158{ 159 struct pfs_vnode *prev, *pv; 160 struct pfs_vdata *pvd; 161 162 mtx_lock(&pfs_vncache_mutex); 163 for (prev = NULL, pv = pfs_vncache; pv; prev = pv, pv = pv->pv_next) 164 if (pv->pv_vnode == vp) 165 break; 166 KASSERT(pv != NULL, ("pfs_vncache_free(): not in cache\n")); 167 if (prev) 168 prev->pv_next = pv->pv_next; 169 else 170 pfs_vncache = pv->pv_next; 171 mtx_unlock(&pfs_vncache_mutex); 172 173 pvd = (struct pfs_vdata *)vp->v_data; 174 FREE(pvd, M_PFSVNCACHE); 175 vp->v_data = NULL; 176 FREE(pv, M_PFSVNCACHE); 177 return (0); 178} 179