1 /* $NetBSD: dead_vnops.c,v 1.45 2007/10/10 20:42:28 ad Exp $ */ 2 3 /* 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * @(#)dead_vnops.c 8.2 (Berkeley) 11/21/94 32 */ 33 34 #include <sys/cdefs.h> 35 __KERNEL_RCSID(0, "$NetBSD: dead_vnops.c,v 1.45 2007/10/10 20:42:28 ad Exp $"); 36 37 #include <sys/param.h> 38 #include <sys/systm.h> 39 #include <sys/time.h> 40 #include <sys/vnode.h> 41 #include <sys/errno.h> 42 #include <sys/namei.h> 43 #include <sys/buf.h> 44 #include <sys/proc.h> 45 46 #include <miscfs/genfs/genfs.h> 47 48 /* 49 * Prototypes for dead operations on vnodes. 50 */ 51 int dead_open(void *); 52 #define dead_close genfs_nullop 53 int dead_read(void *); 54 int dead_write(void *); 55 #define dead_lease_check genfs_nullop 56 #define dead_fcntl genfs_nullop 57 int dead_ioctl(void *); 58 int dead_poll(void *); 59 #define dead_fsync genfs_nullop 60 #define dead_seek genfs_nullop 61 #define dead_inactive genfs_nullop 62 #define dead_reclaim genfs_nullop 63 int dead_lock(void *); 64 #define dead_unlock genfs_nullop 65 int dead_bmap(void *); 66 int dead_strategy(void *); 67 int dead_print(void *); 68 #define dead_islocked genfs_nullop 69 #define dead_bwrite genfs_nullop 70 #define dead_revoke genfs_nullop 71 int dead_getpages(void *); 72 #define dead_putpages genfs_null_putpages 73 74 int chkvnlock(struct vnode *, bool); 75 int dead_default_error(void *); 76 77 int (**dead_vnodeop_p)(void *); 78 79 const struct vnodeopv_entry_desc dead_vnodeop_entries[] = { 80 { &vop_default_desc, dead_default_error }, 81 { &vop_open_desc, dead_open }, /* open */ 82 { &vop_close_desc, dead_close }, /* close */ 83 { &vop_read_desc, dead_read }, /* read */ 84 { &vop_write_desc, dead_write }, /* write */ 85 { &vop_lease_desc, dead_lease_check }, /* lease */ 86 { &vop_fcntl_desc, dead_fcntl }, /* fcntl */ 87 { &vop_ioctl_desc, dead_ioctl }, /* ioctl */ 88 { &vop_poll_desc, dead_poll }, /* poll */ 89 { &vop_revoke_desc, dead_revoke }, /* revoke */ 90 { &vop_fsync_desc, dead_fsync }, /* fsync */ 91 { &vop_seek_desc, dead_seek }, /* seek */ 92 { &vop_inactive_desc, dead_inactive }, /* inactive */ 93 { &vop_reclaim_desc, dead_reclaim }, /* reclaim */ 94 { &vop_lock_desc, dead_lock }, /* lock */ 95 { &vop_unlock_desc, dead_unlock }, /* unlock */ 96 { &vop_bmap_desc, dead_bmap }, /* bmap */ 97 { &vop_strategy_desc, dead_strategy }, /* strategy */ 98 { &vop_print_desc, dead_print }, /* print */ 99 { &vop_islocked_desc, dead_islocked }, /* islocked */ 100 { &vop_bwrite_desc, dead_bwrite }, /* bwrite */ 101 { &vop_getpages_desc, dead_getpages }, /* getpages */ 102 { &vop_putpages_desc, dead_putpages }, /* putpages */ 103 { NULL, NULL } 104 }; 105 const struct vnodeopv_desc dead_vnodeop_opv_desc = 106 { &dead_vnodeop_p, dead_vnodeop_entries }; 107 108 int 109 dead_default_error(void *v) 110 { 111 112 return EBADF; 113 } 114 115 /* 116 * Open always fails as if device did not exist. 117 */ 118 /* ARGSUSED */ 119 int 120 dead_open(void *v) 121 { 122 123 return (ENXIO); 124 } 125 126 /* 127 * Vnode op for read 128 */ 129 /* ARGSUSED */ 130 int 131 dead_read(v) 132 void *v; 133 { 134 struct vop_read_args /* { 135 struct vnode *a_vp; 136 struct uio *a_uio; 137 int a_ioflag; 138 kauth_cred_t a_cred; 139 } */ *ap = v; 140 141 if (chkvnlock(ap->a_vp, false)) 142 panic("dead_read: lock"); 143 /* 144 * Return EOF for tty devices, EIO for others 145 */ 146 if ((ap->a_vp->v_vflag & VV_ISTTY) == 0) 147 return (EIO); 148 return (0); 149 } 150 151 /* 152 * Vnode op for write 153 */ 154 /* ARGSUSED */ 155 int 156 dead_write(v) 157 void *v; 158 { 159 struct vop_write_args /* { 160 struct vnode *a_vp; 161 struct uio *a_uio; 162 int a_ioflag; 163 kauth_cred_t a_cred; 164 } */ *ap = v; 165 166 if (chkvnlock(ap->a_vp, false)) 167 panic("dead_write: lock"); 168 return (EIO); 169 } 170 171 /* 172 * Device ioctl operation. 173 */ 174 /* ARGSUSED */ 175 int 176 dead_ioctl(v) 177 void *v; 178 { 179 struct vop_ioctl_args /* { 180 struct vnode *a_vp; 181 u_long a_command; 182 void *a_data; 183 int a_fflag; 184 kauth_cred_t a_cred; 185 struct lwp *a_l; 186 } */ *ap = v; 187 188 if (!chkvnlock(ap->a_vp, false)) 189 return (EBADF); 190 return (VCALL(ap->a_vp, VOFFSET(vop_ioctl), ap)); 191 } 192 193 /* ARGSUSED */ 194 int 195 dead_poll(v) 196 void *v; 197 { 198 struct vop_poll_args /* { 199 struct vnode *a_vp; 200 int a_events; 201 struct lwp *a_l; 202 } */ *ap = v; 203 204 /* 205 * Let the user find out that the descriptor is gone. 206 */ 207 return (ap->a_events); 208 } 209 210 /* 211 * Just call the device strategy routine 212 */ 213 int 214 dead_strategy(v) 215 void *v; 216 { 217 218 struct vop_strategy_args /* { 219 struct vnode *a_vp; 220 struct buf *a_bp; 221 } */ *ap = v; 222 struct buf *bp; 223 if (ap->a_vp == NULL || !chkvnlock(ap->a_vp, false)) { 224 bp = ap->a_bp; 225 bp->b_error = EIO; 226 bp->b_resid = bp->b_bcount; 227 biodone(ap->a_bp); 228 return (EIO); 229 } 230 return (VOP_STRATEGY(ap->a_vp, ap->a_bp)); 231 } 232 233 /* 234 * Wait until the vnode has finished changing state. 235 */ 236 int 237 dead_lock(v) 238 void *v; 239 { 240 struct vop_lock_args /* { 241 struct vnode *a_vp; 242 int a_flags; 243 struct proc *a_p; 244 } */ *ap = v; 245 bool interlock; 246 247 if (ap->a_flags & LK_INTERLOCK) { 248 interlock = true; 249 ap->a_flags &= ~LK_INTERLOCK; 250 } else 251 interlock = false; 252 if (!chkvnlock(ap->a_vp, interlock)) 253 return (0); 254 return (VCALL(ap->a_vp, VOFFSET(vop_lock), ap)); 255 } 256 257 /* 258 * Wait until the vnode has finished changing state. 259 */ 260 int 261 dead_bmap(v) 262 void *v; 263 { 264 struct vop_bmap_args /* { 265 struct vnode *a_vp; 266 daddr_t a_bn; 267 struct vnode **a_vpp; 268 daddr_t *a_bnp; 269 int *a_runp; 270 } */ *ap = v; 271 272 if (!chkvnlock(ap->a_vp, false)) 273 return (EIO); 274 return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp)); 275 } 276 277 /* 278 * Print out the contents of a dead vnode. 279 */ 280 /* ARGSUSED */ 281 int 282 dead_print(void *v) 283 { 284 printf("tag VT_NON, dead vnode\n"); 285 return 0; 286 } 287 288 int 289 dead_getpages(void *v) 290 { 291 struct vop_getpages_args /* { 292 struct vnode *a_vp; 293 voff_t a_offset; 294 struct vm_page **a_m; 295 int *a_count; 296 int a_centeridx; 297 vm_prot_t a_access_type; 298 int a_advice; 299 int a_flags; 300 } */ *ap = v; 301 302 if ((ap->a_flags & PGO_LOCKED) == 0) 303 simple_unlock(&ap->a_vp->v_interlock); 304 305 return (EFAULT); 306 } 307 308 /* 309 * We have to wait during times when the vnode is 310 * in a state of change. 311 */ 312 int 313 chkvnlock(vp, interlock) 314 struct vnode *vp; 315 bool interlock; 316 { 317 int locked = 0; 318 319 if (!interlock) 320 simple_lock(&vp->v_interlock); 321 while (vp->v_iflag & VI_XLOCK) { 322 vp->v_iflag |= VI_XWANT; 323 (void) tsleep(vp, PINOD, "deadchk", 0); 324 locked = 1; 325 } 326 simple_unlock(&vp->v_interlock); 327 328 return (locked); 329 } 330