xref: /netbsd-src/sys/miscfs/deadfs/dead_vnops.c (revision cda4f8f6ee55684e8d311b86c99ea59191e6b74f)
1 /*
2  * Copyright (c) 1989 The Regents of the University of California.
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  * 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  *	from: @(#)dead_vnops.c	7.13 (Berkeley) 4/15/91
34  *	$Id: dead_vnops.c,v 1.3 1993/06/27 06:01:27 andrew Exp $
35  */
36 
37 #include "param.h"
38 #include "systm.h"
39 #include "time.h"
40 #include "vnode.h"
41 #include "errno.h"
42 #include "namei.h"
43 #include "buf.h"
44 
45 /*
46  * Prototypes for dead operations on vnodes.
47  */
48 volatile void	dead_badop();
49 int	dead_ebadf();
50 int	dead_lookup __P((
51 		struct vnode *vp,
52 		struct nameidata *ndp,
53 		struct proc *p));
54 #define dead_create ((int (*) __P(( \
55 		struct nameidata *ndp, \
56 		struct vattr *vap, \
57 		struct proc *p))) dead_badop)
58 #define dead_mknod ((int (*) __P(( \
59 		struct nameidata *ndp, \
60 		struct vattr *vap, \
61 		struct ucred *cred, \
62 		struct proc *p))) dead_badop)
63 int	dead_open __P((
64 		struct vnode *vp,
65 		int mode,
66 		struct ucred *cred,
67 		struct proc *p));
68 #define dead_close ((int (*) __P(( \
69 		struct vnode *vp, \
70 		int fflag, \
71 		struct ucred *cred, \
72 		struct proc *p))) nullop)
73 #define dead_access ((int (*) __P(( \
74 		struct vnode *vp, \
75 		int mode, \
76 		struct ucred *cred, \
77 		struct proc *p))) dead_ebadf)
78 #define dead_getattr ((int (*) __P(( \
79 		struct vnode *vp, \
80 		struct vattr *vap, \
81 		struct ucred *cred, \
82 		struct proc *p))) dead_ebadf)
83 #define dead_setattr ((int (*) __P(( \
84 		struct vnode *vp, \
85 		struct vattr *vap, \
86 		struct ucred *cred, \
87 		struct proc *p))) dead_ebadf)
88 int	dead_read __P((
89 		struct vnode *vp,
90 		struct uio *uio,
91 		int ioflag,
92 		struct ucred *cred));
93 int	dead_write __P((
94 		struct vnode *vp,
95 		struct uio *uio,
96 		int ioflag,
97 		struct ucred *cred));
98 int	dead_ioctl __P((
99 		struct vnode *vp,
100 		int command,
101 		caddr_t data,
102 		int fflag,
103 		struct ucred *cred,
104 		struct proc *p));
105 int	dead_select __P((
106 		struct vnode *vp,
107 		int which,
108 		int fflags,
109 		struct ucred *cred,
110 		struct proc *p));
111 #define dead_mmap ((int (*) __P(( \
112 		struct vnode *vp, \
113 		int fflags, \
114 		struct ucred *cred, \
115 		struct proc *p))) dead_badop)
116 #define dead_fsync ((int (*) __P(( \
117 		struct vnode *vp, \
118 		int fflags, \
119 		struct ucred *cred, \
120 		int waitfor, \
121 		struct proc *p))) nullop)
122 #define dead_seek ((int (*) __P(( \
123 		struct vnode *vp, \
124 		off_t oldoff, \
125 		off_t newoff, \
126 		struct ucred *cred))) nullop)
127 #define dead_remove ((int (*) __P(( \
128 		struct nameidata *ndp, \
129 		struct proc *p))) dead_badop)
130 #define dead_link ((int (*) __P(( \
131 		struct vnode *vp, \
132 		struct nameidata *ndp, \
133 		struct proc *p))) dead_badop)
134 #define dead_rename ((int (*) __P(( \
135 		struct nameidata *fndp, \
136 		struct nameidata *tdnp, \
137 		struct proc *p))) dead_badop)
138 #define dead_mkdir ((int (*) __P(( \
139 		struct nameidata *ndp, \
140 		struct vattr *vap, \
141 		struct proc *p))) dead_badop)
142 #define dead_rmdir ((int (*) __P(( \
143 		struct nameidata *ndp, \
144 		struct proc *p))) dead_badop)
145 #define dead_symlink ((int (*) __P(( \
146 		struct nameidata *ndp, \
147 		struct vattr *vap, \
148 		char *target, \
149 		struct proc *p))) dead_badop)
150 #define dead_readdir ((int (*) __P(( \
151 		struct vnode *vp, \
152 		struct uio *uio, \
153 		struct ucred *cred, \
154 		int *eofflagp))) dead_ebadf)
155 #define dead_readlink ((int (*) __P(( \
156 		struct vnode *vp, \
157 		struct uio *uio, \
158 		struct ucred *cred))) dead_ebadf)
159 #define dead_abortop ((int (*) __P(( \
160 		struct nameidata *ndp))) dead_badop)
161 #define dead_inactive ((int (*) __P(( \
162 		struct vnode *vp, \
163 		struct proc *p))) nullop)
164 #define dead_reclaim ((int (*) __P(( \
165 		struct vnode *vp))) nullop)
166 int	dead_lock __P((
167 		struct vnode *vp));
168 #define dead_unlock ((int (*) __P(( \
169 		struct vnode *vp))) nullop)
170 int	dead_bmap __P((
171 		struct vnode *vp,
172 		daddr_t bn,
173 		struct vnode **vpp,
174 		daddr_t *bnp));
175 int	dead_strategy __P((
176 		struct buf *bp));
177 void	dead_print __P((
178 		struct vnode *vp));
179 #define dead_islocked ((int (*) __P(( \
180 		struct vnode *vp))) nullop)
181 #define dead_advlock ((int (*) __P(( \
182 		struct vnode *vp, \
183 		caddr_t id, \
184 		int op, \
185 		struct flock *fl, \
186 		int flags))) dead_ebadf)
187 int	chkvnlock __P((
188 		struct vnode *vp));
189 
190 struct vnodeops dead_vnodeops = {
191 	dead_lookup,	/* lookup */
192 	dead_create,	/* create */
193 	dead_mknod,	/* mknod */
194 	dead_open,	/* open */
195 	dead_close,	/* close */
196 	dead_access,	/* access */
197 	dead_getattr,	/* getattr */
198 	dead_setattr,	/* setattr */
199 	dead_read,	/* read */
200 	dead_write,	/* write */
201 	dead_ioctl,	/* ioctl */
202 	dead_select,	/* select */
203 	dead_mmap,	/* mmap */
204 	dead_fsync,	/* fsync */
205 	dead_seek,	/* seek */
206 	dead_remove,	/* remove */
207 	dead_link,	/* link */
208 	dead_rename,	/* rename */
209 	dead_mkdir,	/* mkdir */
210 	dead_rmdir,	/* rmdir */
211 	dead_symlink,	/* symlink */
212 	dead_readdir,	/* readdir */
213 	dead_readlink,	/* readlink */
214 	dead_abortop,	/* abortop */
215 	dead_inactive,	/* inactive */
216 	dead_reclaim,	/* reclaim */
217 	dead_lock,	/* lock */
218 	dead_unlock,	/* unlock */
219 	dead_bmap,	/* bmap */
220 	dead_strategy,	/* strategy */
221 	dead_print,	/* print */
222 	dead_islocked,	/* islocked */
223 	dead_advlock,	/* advlock */
224 };
225 
226 /*
227  * Trivial lookup routine that always fails.
228  */
229 /* ARGSUSED */
230 int
231 dead_lookup(vp, ndp, p)
232 	struct vnode *vp;
233 	struct nameidata *ndp;
234 	struct proc *p;
235 {
236 
237 	ndp->ni_dvp = vp;
238 	ndp->ni_vp = NULL;
239 	return (ENOTDIR);
240 }
241 
242 /*
243  * Open always fails as if device did not exist.
244  */
245 /* ARGSUSED */
246 int
247 dead_open(vp, mode, cred, p)
248 	struct vnode *vp;
249 	int mode;
250 	struct ucred *cred;
251 	struct proc *p;
252 {
253 
254 	return (ENXIO);
255 }
256 
257 /*
258  * Vnode op for read
259  */
260 /* ARGSUSED */
261 int
262 dead_read(vp, uio, ioflag, cred)
263 	struct vnode *vp;
264 	struct uio *uio;
265 	int ioflag;
266 	struct ucred *cred;
267 {
268 
269 	if (chkvnlock(vp))
270 		panic("dead_read: lock");
271 	/*
272 	 * Return EOF for character devices, EIO for others
273 	 */
274 	if (vp->v_type != VCHR)
275 		return (EIO);
276 	return (0);
277 }
278 
279 /*
280  * Vnode op for write
281  */
282 /* ARGSUSED */
283 int
284 dead_write(vp, uio, ioflag, cred)
285 	register struct vnode *vp;
286 	struct uio *uio;
287 	int ioflag;
288 	struct ucred *cred;
289 {
290 
291 	if (chkvnlock(vp))
292 		panic("dead_write: lock");
293 	return (EIO);
294 }
295 
296 /*
297  * Device ioctl operation.
298  */
299 /* ARGSUSED */
300 int
301 dead_ioctl(vp, com, data, fflag, cred, p)
302 	struct vnode *vp;
303 	register int com;
304 	caddr_t data;
305 	int fflag;
306 	struct ucred *cred;
307 	struct proc *p;
308 {
309 
310 	if (!chkvnlock(vp))
311 		return (EBADF);
312 	return (VOP_IOCTL(vp, com, data, fflag, cred, p));
313 }
314 
315 /* ARGSUSED */
316 int
317 dead_select(vp, which, fflags, cred, p)
318 	struct vnode *vp;
319 	int which, fflags;
320 	struct ucred *cred;
321 	struct proc *p;
322 {
323 
324 	/*
325 	 * Let the user find out that the descriptor is gone.
326 	 */
327 	return (1);
328 }
329 
330 /*
331  * Just call the device strategy routine
332  */
333 int
334 dead_strategy(bp)
335 	register struct buf *bp;
336 {
337 
338 	if (bp->b_vp == NULL || !chkvnlock(bp->b_vp)) {
339 		bp->b_flags |= B_ERROR;
340 		biodone(bp);
341 		return (EIO);
342 	}
343 	return (VOP_STRATEGY(bp));
344 }
345 
346 /*
347  * Wait until the vnode has finished changing state.
348  */
349 int
350 dead_lock(vp)
351 	struct vnode *vp;
352 {
353 
354 	if (!chkvnlock(vp))
355 		return (0);
356 	return (VOP_LOCK(vp));
357 }
358 
359 /*
360  * Wait until the vnode has finished changing state.
361  */
362 int
363 dead_bmap(vp, bn, vpp, bnp)
364 	struct vnode *vp;
365 	daddr_t bn;
366 	struct vnode **vpp;
367 	daddr_t *bnp;
368 {
369 
370 	if (!chkvnlock(vp))
371 		return (EIO);
372 	return (VOP_BMAP(vp, bn, vpp, bnp));
373 }
374 
375 /*
376  * Print out the contents of a dead vnode.
377  */
378 /* ARGSUSED */
379 void
380 dead_print(vp)
381 	struct vnode *vp;
382 {
383 
384 	printf("tag VT_NON, dead vnode\n");
385 }
386 
387 /*
388  * Empty vnode failed operation
389  */
390 int
391 dead_ebadf()
392 {
393 
394 	return (EBADF);
395 }
396 
397 /*
398  * Empty vnode bad operation
399  */
400 volatile void
401 dead_badop()
402 {
403 
404 	panic("dead_badop called");
405 	/* NOTREACHED */
406 }
407 
408 /*
409  * Empty vnode null operation
410  */
411 int
412 dead_nullop()
413 {
414 
415 	return (0);
416 }
417 
418 /*
419  * We have to wait during times when the vnode is
420  * in a state of change.
421  */
422 int
423 chkvnlock(vp)
424 	register struct vnode *vp;
425 {
426 	int locked = 0;
427 
428 	while (vp->v_flag & VXLOCK) {
429 		vp->v_flag |= VXWANT;
430 		sleep((caddr_t)vp, PINOD);
431 		locked = 1;
432 	}
433 	return (locked);
434 }
435