dead_vnops.c revision 95944
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 95944 2002-05-02 19:13:44Z 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_print(struct vop_print_args *); 56static int dead_read(struct vop_read_args *); 57static int dead_write(struct vop_write_args *); 58 59vop_t **dead_vnodeop_p; 60static struct vnodeopv_entry_desc dead_vnodeop_entries[] = { 61 { &vop_default_desc, (vop_t *) vop_defaultop }, 62 { &vop_access_desc, (vop_t *) vop_ebadf }, 63 { &vop_advlock_desc, (vop_t *) vop_ebadf }, 64 { &vop_bmap_desc, (vop_t *) dead_bmap }, 65 { &vop_create_desc, (vop_t *) vop_panic }, 66 { &vop_getattr_desc, (vop_t *) vop_ebadf }, 67 { &vop_inactive_desc, (vop_t *) vop_null }, 68 { &vop_ioctl_desc, (vop_t *) dead_ioctl }, 69 { &vop_link_desc, (vop_t *) vop_panic }, 70 { &vop_lock_desc, (vop_t *) dead_lock }, 71 { &vop_lookup_desc, (vop_t *) dead_lookup }, 72 { &vop_mkdir_desc, (vop_t *) vop_panic }, 73 { &vop_mknod_desc, (vop_t *) vop_panic }, 74 { &vop_open_desc, (vop_t *) dead_open }, 75 { &vop_pathconf_desc, (vop_t *) vop_ebadf }, /* per pathconf(2) */ 76 { &vop_poll_desc, (vop_t *) dead_poll }, 77 { &vop_print_desc, (vop_t *) dead_print }, 78 { &vop_read_desc, (vop_t *) dead_read }, 79 { &vop_readdir_desc, (vop_t *) vop_ebadf }, 80 { &vop_readlink_desc, (vop_t *) vop_ebadf }, 81 { &vop_reclaim_desc, (vop_t *) vop_null }, 82 { &vop_remove_desc, (vop_t *) vop_panic }, 83 { &vop_rename_desc, (vop_t *) vop_panic }, 84 { &vop_rmdir_desc, (vop_t *) vop_panic }, 85 { &vop_setattr_desc, (vop_t *) vop_ebadf }, 86 { &vop_symlink_desc, (vop_t *) vop_panic }, 87 { &vop_write_desc, (vop_t *) dead_write }, 88 { NULL, NULL } 89}; 90static struct vnodeopv_desc dead_vnodeop_opv_desc = 91 { &dead_vnodeop_p, dead_vnodeop_entries }; 92 93VNODEOP_SET(dead_vnodeop_opv_desc); 94 95/* 96 * Trivial lookup routine that always fails. 97 */ 98/* ARGSUSED */ 99static int 100dead_lookup(ap) 101 struct vop_lookup_args /* { 102 struct vnode * a_dvp; 103 struct vnode ** a_vpp; 104 struct componentname * a_cnp; 105 } */ *ap; 106{ 107 108 *ap->a_vpp = NULL; 109 return (ENOTDIR); 110} 111 112/* 113 * Open always fails as if device did not exist. 114 */ 115/* ARGSUSED */ 116static int 117dead_open(ap) 118 struct vop_open_args /* { 119 struct vnode *a_vp; 120 int a_mode; 121 struct ucred *a_cred; 122 struct proc *a_p; 123 } */ *ap; 124{ 125 126 return (ENXIO); 127} 128 129/* 130 * Vnode op for read 131 */ 132/* ARGSUSED */ 133static int 134dead_read(ap) 135 struct vop_read_args /* { 136 struct vnode *a_vp; 137 struct uio *a_uio; 138 int a_ioflag; 139 struct ucred *a_cred; 140 } */ *ap; 141{ 142 143 if (chkvnlock(ap->a_vp)) 144 panic("dead_read: lock"); 145 /* 146 * Return EOF for tty devices, EIO for others 147 */ 148 if ((ap->a_vp->v_flag & VISTTY) == 0) 149 return (EIO); 150 return (0); 151} 152 153/* 154 * Vnode op for write 155 */ 156/* ARGSUSED */ 157static int 158dead_write(ap) 159 struct vop_write_args /* { 160 struct vnode *a_vp; 161 struct uio *a_uio; 162 int a_ioflag; 163 struct ucred *a_cred; 164 } */ *ap; 165{ 166 167 if (chkvnlock(ap->a_vp)) 168 panic("dead_write: lock"); 169 return (EIO); 170} 171 172/* 173 * Device ioctl operation. 174 */ 175/* ARGSUSED */ 176static int 177dead_ioctl(ap) 178 struct vop_ioctl_args /* { 179 struct vnode *a_vp; 180 int a_command; 181 caddr_t a_data; 182 int a_fflag; 183 struct ucred *a_cred; 184 struct proc *a_p; 185 } */ *ap; 186{ 187 188 if (!chkvnlock(ap->a_vp)) 189 return (ENOTTY); 190 return (VCALL(ap->a_vp, VOFFSET(vop_ioctl), ap)); 191} 192 193 194/* 195 * Wait until the vnode has finished changing state. 196 */ 197static int 198dead_lock(ap) 199 struct vop_lock_args /* { 200 struct vnode *a_vp; 201 int a_flags; 202 struct proc *a_p; 203 } */ *ap; 204{ 205 struct vnode *vp = ap->a_vp; 206 207 /* 208 * Since we are not using the lock manager, we must clear 209 * the interlock here. 210 */ 211 if (ap->a_flags & LK_INTERLOCK) { 212 mtx_unlock(&vp->v_interlock); 213 ap->a_flags &= ~LK_INTERLOCK; 214 } 215 if (!chkvnlock(vp)) 216 return (0); 217 return (VCALL(vp, VOFFSET(vop_lock), ap)); 218} 219 220/* 221 * Wait until the vnode has finished changing state. 222 */ 223static int 224dead_bmap(ap) 225 struct vop_bmap_args /* { 226 struct vnode *a_vp; 227 daddr_t a_bn; 228 struct vnode **a_vpp; 229 daddr_t *a_bnp; 230 int *a_runp; 231 int *a_runb; 232 } */ *ap; 233{ 234 235 if (!chkvnlock(ap->a_vp)) 236 return (EIO); 237 return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp, ap->a_runb)); 238} 239 240/* 241 * Print out the contents of a dead vnode. 242 */ 243/* ARGSUSED */ 244static int 245dead_print(ap) 246 struct vop_print_args /* { 247 struct vnode *a_vp; 248 } */ *ap; 249{ 250 251 printf("tag VT_NON, dead vnode\n"); 252 return (0); 253} 254 255/* 256 * We have to wait during times when the vnode is 257 * in a state of change. 258 */ 259int 260chkvnlock(vp) 261 register struct vnode *vp; 262{ 263 int locked = 0; 264 265 while (vp->v_flag & VXLOCK) { 266 vp->v_flag |= VXWANT; 267 (void) tsleep((caddr_t)vp, PINOD, "ckvnlk", 0); 268 locked = 1; 269 } 270 return (locked); 271} 272 273/* 274 * Trivial poll routine that always returns POLLHUP. 275 * This is necessary so that a process which is polling a file 276 * gets notified when that file is revoke()d. 277 */ 278static int 279dead_poll(ap) 280 struct vop_poll_args *ap; 281{ 282 return (POLLHUP); 283} 284