1 /* $NetBSD: dead_vnops.c,v 1.48 2009/03/14 21:04:24 dsl 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 1.48 2009/03/14 21:04:24 dsl 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_fcntl genfs_nullop 56 int dead_ioctl(void *); 57 int dead_poll(void *); 58 #define dead_fsync genfs_nullop 59 #define dead_seek genfs_nullop 60 #define dead_inactive genfs_nullop 61 #define dead_reclaim genfs_nullop 62 int dead_lock(void *); 63 #define dead_unlock genfs_nullop 64 int dead_bmap(void *); 65 int dead_strategy(void *); 66 int dead_print(void *); 67 #define dead_islocked genfs_nullop 68 #define dead_bwrite genfs_nullop 69 #define dead_revoke genfs_nullop 70 int dead_getpages(void *); 71 #define dead_putpages genfs_null_putpages 72 73 int chkvnlock(struct vnode *, bool); 74 int dead_default_error(void *); 75 76 int (**dead_vnodeop_p)(void *); 77 78 const struct vnodeopv_entry_desc dead_vnodeop_entries[] = { 79 { &vop_default_desc, dead_default_error }, 80 { &vop_open_desc, dead_open }, /* open */ 81 { &vop_close_desc, dead_close }, /* close */ 82 { &vop_read_desc, dead_read }, /* read */ 83 { &vop_write_desc, dead_write }, /* write */ 84 { &vop_fcntl_desc, dead_fcntl }, /* fcntl */ 85 { &vop_ioctl_desc, dead_ioctl }, /* ioctl */ 86 { &vop_poll_desc, dead_poll }, /* poll */ 87 { &vop_revoke_desc, dead_revoke }, /* revoke */ 88 { &vop_fsync_desc, dead_fsync }, /* fsync */ 89 { &vop_seek_desc, dead_seek }, /* seek */ 90 { &vop_inactive_desc, dead_inactive }, /* inactive */ 91 { &vop_reclaim_desc, dead_reclaim }, /* reclaim */ 92 { &vop_lock_desc, dead_lock }, /* lock */ 93 { &vop_unlock_desc, dead_unlock }, /* unlock */ 94 { &vop_bmap_desc, dead_bmap }, /* bmap */ 95 { &vop_strategy_desc, dead_strategy }, /* strategy */ 96 { &vop_print_desc, dead_print }, /* print */ 97 { &vop_islocked_desc, dead_islocked }, /* islocked */ 98 { &vop_bwrite_desc, dead_bwrite }, /* bwrite */ 99 { &vop_getpages_desc, dead_getpages }, /* getpages */ 100 { &vop_putpages_desc, dead_putpages }, /* putpages */ 101 { NULL, NULL } 102 }; 103 const struct vnodeopv_desc dead_vnodeop_opv_desc = 104 { &dead_vnodeop_p, dead_vnodeop_entries }; 105 106 int 107 dead_default_error(void *v) 108 { 109 110 return EBADF; 111 } 112 113 /* 114 * Open always fails as if device did not exist. 115 */ 116 /* ARGSUSED */ 117 int 118 dead_open(void *v) 119 { 120 121 return (ENXIO); 122 } 123 124 /* 125 * Vnode op for read 126 */ 127 /* ARGSUSED */ 128 int 129 dead_read(void *v) 130 { 131 struct vop_read_args /* { 132 struct vnode *a_vp; 133 struct uio *a_uio; 134 int a_ioflag; 135 kauth_cred_t a_cred; 136 } */ *ap = v; 137 138 if (chkvnlock(ap->a_vp, false)) 139 panic("dead_read: lock"); 140 /* 141 * Return EOF for tty devices, EIO for others 142 */ 143 if ((ap->a_vp->v_vflag & VV_ISTTY) == 0) 144 return (EIO); 145 return (0); 146 } 147 148 /* 149 * Vnode op for write 150 */ 151 /* ARGSUSED */ 152 int 153 dead_write(void *v) 154 { 155 struct vop_write_args /* { 156 struct vnode *a_vp; 157 struct uio *a_uio; 158 int a_ioflag; 159 kauth_cred_t a_cred; 160 } */ *ap = v; 161 162 if (chkvnlock(ap->a_vp, false)) 163 panic("dead_write: lock"); 164 return (EIO); 165 } 166 167 /* 168 * Device ioctl operation. 169 */ 170 /* ARGSUSED */ 171 int 172 dead_ioctl(void *v) 173 { 174 struct vop_ioctl_args /* { 175 struct vnode *a_vp; 176 u_long a_command; 177 void *a_data; 178 int a_fflag; 179 kauth_cred_t a_cred; 180 struct lwp *a_l; 181 } */ *ap = v; 182 183 if (!chkvnlock(ap->a_vp, false)) 184 return (EBADF); 185 return (VCALL(ap->a_vp, VOFFSET(vop_ioctl), ap)); 186 } 187 188 /* ARGSUSED */ 189 int 190 dead_poll(void *v) 191 { 192 struct vop_poll_args /* { 193 struct vnode *a_vp; 194 int a_events; 195 struct lwp *a_l; 196 } */ *ap = v; 197 198 /* 199 * Let the user find out that the descriptor is gone. 200 */ 201 return (ap->a_events); 202 } 203 204 /* 205 * Just call the device strategy routine 206 */ 207 int 208 dead_strategy(void *v) 209 { 210 211 struct vop_strategy_args /* { 212 struct vnode *a_vp; 213 struct buf *a_bp; 214 } */ *ap = v; 215 struct buf *bp; 216 if (ap->a_vp == NULL || !chkvnlock(ap->a_vp, false)) { 217 bp = ap->a_bp; 218 bp->b_error = EIO; 219 bp->b_resid = bp->b_bcount; 220 biodone(ap->a_bp); 221 return (EIO); 222 } 223 return (VOP_STRATEGY(ap->a_vp, ap->a_bp)); 224 } 225 226 /* 227 * Wait until the vnode has finished changing state. 228 */ 229 int 230 dead_lock(void *v) 231 { 232 struct vop_lock_args /* { 233 struct vnode *a_vp; 234 int a_flags; 235 struct proc *a_p; 236 } */ *ap = v; 237 bool interlock; 238 239 if (ap->a_flags & LK_INTERLOCK) { 240 interlock = true; 241 ap->a_flags &= ~LK_INTERLOCK; 242 } else 243 interlock = false; 244 if (!chkvnlock(ap->a_vp, interlock)) 245 return (0); 246 return (VCALL(ap->a_vp, VOFFSET(vop_lock), ap)); 247 } 248 249 /* 250 * Wait until the vnode has finished changing state. 251 */ 252 int 253 dead_bmap(void *v) 254 { 255 struct vop_bmap_args /* { 256 struct vnode *a_vp; 257 daddr_t a_bn; 258 struct vnode **a_vpp; 259 daddr_t *a_bnp; 260 int *a_runp; 261 } */ *ap = v; 262 263 if (!chkvnlock(ap->a_vp, false)) 264 return (EIO); 265 return (VOP_BMAP(ap->a_vp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp)); 266 } 267 268 /* 269 * Print out the contents of a dead vnode. 270 */ 271 /* ARGSUSED */ 272 int 273 dead_print(void *v) 274 { 275 printf("tag VT_NON, dead vnode\n"); 276 return 0; 277 } 278 279 int 280 dead_getpages(void *v) 281 { 282 struct vop_getpages_args /* { 283 struct vnode *a_vp; 284 voff_t a_offset; 285 struct vm_page **a_m; 286 int *a_count; 287 int a_centeridx; 288 vm_prot_t a_access_type; 289 int a_advice; 290 int a_flags; 291 } */ *ap = v; 292 293 if ((ap->a_flags & PGO_LOCKED) == 0) 294 mutex_exit(&ap->a_vp->v_interlock); 295 296 return (EFAULT); 297 } 298 299 /* 300 * We have to wait during times when the vnode is 301 * in a state of change. 302 */ 303 int 304 chkvnlock(struct vnode *vp, bool interlock) 305 { 306 int locked = 0; 307 308 if (!interlock) 309 mutex_enter(&vp->v_interlock); 310 while (vp->v_iflag & VI_XLOCK) { 311 vwait(vp, VI_XLOCK); 312 locked = 1; 313 } 314 mutex_exit(&vp->v_interlock); 315 316 return (locked); 317 } 318