dead_vnops.c revision 104094
1/* 2 * Copyright (c) 1989, 1993 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 * @(#)dead_vnops.c 8.1 (Berkeley) 6/10/93 34 * $FreeBSD: head/sys/fs/deadfs/dead_vnops.c 104094 2002-09-28 17:15:38Z phk $ 35 */ 36 37#include <sys/param.h> 38#include <sys/systm.h> 39#include <sys/kernel.h> 40#include <sys/lock.h> 41#include <sys/mutex.h> 42#include <sys/poll.h> 43#include <sys/vnode.h> 44 45static int chkvnlock(struct vnode *); 46/* 47 * Prototypes for dead operations on vnodes. 48 */ 49static int dead_bmap(struct vop_bmap_args *); 50static int dead_ioctl(struct vop_ioctl_args *); 51static int dead_lock(struct vop_lock_args *); 52static int dead_lookup(struct vop_lookup_args *); 53static int dead_open(struct vop_open_args *); 54static int dead_poll(struct vop_poll_args *); 55static int dead_read(struct vop_read_args *); 56static int dead_write(struct vop_write_args *); 57 58vop_t **dead_vnodeop_p; 59static struct vnodeopv_entry_desc dead_vnodeop_entries[] = { 60 { &vop_default_desc, (vop_t *) vop_defaultop }, 61 { &vop_access_desc, (vop_t *) vop_ebadf }, 62 { &vop_advlock_desc, (vop_t *) vop_ebadf }, 63 { &vop_bmap_desc, (vop_t *) dead_bmap }, 64 { &vop_create_desc, (vop_t *) vop_panic }, 65 { &vop_getattr_desc, (vop_t *) vop_ebadf }, 66 { &vop_inactive_desc, (vop_t *) vop_null }, 67 { &vop_ioctl_desc, (vop_t *) dead_ioctl }, 68 { &vop_link_desc, (vop_t *) vop_panic }, 69 { &vop_lock_desc, (vop_t *) dead_lock }, 70 { &vop_lookup_desc, (vop_t *) dead_lookup }, 71 { &vop_mkdir_desc, (vop_t *) vop_panic }, 72 { &vop_mknod_desc, (vop_t *) vop_panic }, 73 { &vop_open_desc, (vop_t *) dead_open }, 74 { &vop_pathconf_desc, (vop_t *) vop_ebadf }, /* per pathconf(2) */ 75 { &vop_poll_desc, (vop_t *) dead_poll }, 76 { &vop_print_desc, (vop_t *) vop_null }, 77 { &vop_read_desc, (vop_t *) dead_read }, 78 { &vop_readdir_desc, (vop_t *) vop_ebadf }, 79 { &vop_readlink_desc, (vop_t *) vop_ebadf }, 80 { &vop_reclaim_desc, (vop_t *) vop_null }, 81 { &vop_remove_desc, (vop_t *) vop_panic }, 82 { &vop_rename_desc, (vop_t *) vop_panic }, 83 { &vop_rmdir_desc, (vop_t *) vop_panic }, 84 { &vop_setattr_desc, (vop_t *) vop_ebadf }, 85 { &vop_symlink_desc, (vop_t *) vop_panic }, 86 { &vop_write_desc, (vop_t *) dead_write }, 87 { NULL, NULL } 88}; 89static struct vnodeopv_desc dead_vnodeop_opv_desc = 90 { &dead_vnodeop_p, dead_vnodeop_entries }; 91 92VNODEOP_SET(dead_vnodeop_opv_desc); 93 94/* 95 * Trivial lookup routine that always fails. 96 */ 97/* ARGSUSED */ 98static int 99dead_lookup(ap) 100 struct vop_lookup_args /* { 101 struct vnode * a_dvp; 102 struct vnode ** a_vpp; 103 struct componentname * a_cnp; 104 } */ *ap; 105{ 106 107 *ap->a_vpp = NULL; 108 return (ENOTDIR); 109} 110 111/* 112 * Open always fails as if device did not exist. 113 */ 114/* ARGSUSED */ 115static int 116dead_open(ap) 117 struct vop_open_args /* { 118 struct vnode *a_vp; 119 int a_mode; 120 struct ucred *a_cred; 121 struct proc *a_p; 122 } */ *ap; 123{ 124 125 return (ENXIO); 126} 127 128/* 129 * Vnode op for read 130 */ 131/* ARGSUSED */ 132static int 133dead_read(ap) 134 struct vop_read_args /* { 135 struct vnode *a_vp; 136 struct uio *a_uio; 137 int a_ioflag; 138 struct ucred *a_cred; 139 } */ *ap; 140{ 141 142 if (chkvnlock(ap->a_vp)) 143 panic("dead_read: lock"); 144 /* 145 * Return EOF for tty devices, EIO for others 146 */ 147 if ((ap->a_vp->v_vflag & VV_ISTTY) == 0) 148 return (EIO); 149 return (0); 150} 151 152/* 153 * Vnode op for write 154 */ 155/* ARGSUSED */ 156static int 157dead_write(ap) 158 struct vop_write_args /* { 159 struct vnode *a_vp; 160 struct uio *a_uio; 161 int a_ioflag; 162 struct ucred *a_cred; 163 } */ *ap; 164{ 165 166 if (chkvnlock(ap->a_vp)) 167 panic("dead_write: lock"); 168 return (EIO); 169} 170 171/* 172 * Device ioctl operation. 173 */ 174/* ARGSUSED */ 175static int 176dead_ioctl(ap) 177 struct vop_ioctl_args /* { 178 struct vnode *a_vp; 179 int a_command; 180 caddr_t a_data; 181 int a_fflag; 182 struct ucred *a_cred; 183 struct proc *a_p; 184 } */ *ap; 185{ 186 187 if (!chkvnlock(ap->a_vp)) 188 return (ENOTTY); 189 return (VCALL(ap->a_vp, VOFFSET(vop_ioctl), ap)); 190} 191 192 193/* 194 * Wait until the vnode has finished changing state. 195 */ 196static int 197dead_lock(ap) 198 struct vop_lock_args /* { 199 struct vnode *a_vp; 200 int a_flags; 201 struct proc *a_p; 202 } */ *ap; 203{ 204 struct vnode *vp = ap->a_vp; 205 206 /* 207 * Since we are not using the lock manager, we must clear 208 * the interlock here. 209 */ 210 if (ap->a_flags & LK_INTERLOCK) { 211 mtx_unlock(&vp->v_interlock); 212 ap->a_flags &= ~LK_INTERLOCK; 213 } 214 if (!chkvnlock(vp)) 215 return (0); 216 return (VCALL(vp, VOFFSET(vop_lock), ap)); 217} 218 219/* 220 * Wait until the vnode has finished changing state. 221 */ 222static int 223dead_bmap(ap) 224 struct vop_bmap_args /* { 225 struct vnode *a_vp; 226 daddr_t a_bn; 227 struct vnode **a_vpp; 228 daddr_t *a_bnp; 229 int *a_runp; 230 int *a_runb; 231 } */ *ap; 232{ 233 234 if (!chkvnlock(ap->a_vp)) 235 return (EIO); 236 return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp, ap->a_runb)); 237} 238 239/* 240 * We have to wait during times when the vnode is 241 * in a state of change. 242 */ 243static int 244chkvnlock(vp) 245 register struct vnode *vp; 246{ 247 int locked = 0; 248 249 VI_LOCK(vp); 250 while (vp->v_iflag & VI_XLOCK) { 251 vp->v_iflag |= VI_XWANT; 252 (void) msleep((caddr_t)vp, VI_MTX(vp), PINOD, "ckvnlk", 0); 253 locked = 1; 254 } 255 VI_UNLOCK(vp); 256 return (locked); 257} 258 259/* 260 * Trivial poll routine that always returns POLLHUP. 261 * This is necessary so that a process which is polling a file 262 * gets notified when that file is revoke()d. 263 */ 264static int 265dead_poll(ap) 266 struct vop_poll_args *ap; 267{ 268 return (POLLHUP); 269} 270