xref: /netbsd-src/sys/miscfs/deadfs/dead_vnops.c (revision 4b30c543a0b21e3ba94f2c569e9a82b4fdb2075f)
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 1.5 1993/09/07 15:41:08 ws 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, \
155 		u_int *cookies, \
156 		int ncookies))) dead_ebadf)
157 #define dead_readlink ((int (*) __P(( \
158 		struct vnode *vp, \
159 		struct uio *uio, \
160 		struct ucred *cred))) dead_ebadf)
161 #define dead_abortop ((int (*) __P(( \
162 		struct nameidata *ndp))) dead_badop)
163 #define dead_inactive ((int (*) __P(( \
164 		struct vnode *vp, \
165 		struct proc *p))) nullop)
166 #define dead_reclaim ((int (*) __P(( \
167 		struct vnode *vp))) nullop)
168 int	dead_lock __P((
169 		struct vnode *vp));
170 #define dead_unlock ((int (*) __P(( \
171 		struct vnode *vp))) nullop)
172 int	dead_bmap __P((
173 		struct vnode *vp,
174 		daddr_t bn,
175 		struct vnode **vpp,
176 		daddr_t *bnp));
177 int	dead_strategy __P((
178 		struct buf *bp));
179 void	dead_print __P((
180 		struct vnode *vp));
181 #define dead_islocked ((int (*) __P(( \
182 		struct vnode *vp))) nullop)
183 #define dead_advlock ((int (*) __P(( \
184 		struct vnode *vp, \
185 		caddr_t id, \
186 		int op, \
187 		struct flock *fl, \
188 		int flags))) dead_ebadf)
189 int	chkvnlock __P((
190 		struct vnode *vp));
191 
192 struct vnodeops dead_vnodeops = {
193 	dead_lookup,	/* lookup */
194 	dead_create,	/* create */
195 	dead_mknod,	/* mknod */
196 	dead_open,	/* open */
197 	dead_close,	/* close */
198 	dead_access,	/* access */
199 	dead_getattr,	/* getattr */
200 	dead_setattr,	/* setattr */
201 	dead_read,	/* read */
202 	dead_write,	/* write */
203 	dead_ioctl,	/* ioctl */
204 	dead_select,	/* select */
205 	dead_mmap,	/* mmap */
206 	dead_fsync,	/* fsync */
207 	dead_seek,	/* seek */
208 	dead_remove,	/* remove */
209 	dead_link,	/* link */
210 	dead_rename,	/* rename */
211 	dead_mkdir,	/* mkdir */
212 	dead_rmdir,	/* rmdir */
213 	dead_symlink,	/* symlink */
214 	dead_readdir,	/* readdir */
215 	dead_readlink,	/* readlink */
216 	dead_abortop,	/* abortop */
217 	dead_inactive,	/* inactive */
218 	dead_reclaim,	/* reclaim */
219 	dead_lock,	/* lock */
220 	dead_unlock,	/* unlock */
221 	dead_bmap,	/* bmap */
222 	dead_strategy,	/* strategy */
223 	dead_print,	/* print */
224 	dead_islocked,	/* islocked */
225 	dead_advlock,	/* advlock */
226 };
227 
228 /*
229  * Trivial lookup routine that always fails.
230  */
231 /* ARGSUSED */
232 int
233 dead_lookup(vp, ndp, p)
234 	struct vnode *vp;
235 	struct nameidata *ndp;
236 	struct proc *p;
237 {
238 
239 	ndp->ni_dvp = vp;
240 	ndp->ni_vp = NULL;
241 	return (ENOTDIR);
242 }
243 
244 /*
245  * Open always fails as if device did not exist.
246  */
247 /* ARGSUSED */
248 int
249 dead_open(vp, mode, cred, p)
250 	struct vnode *vp;
251 	int mode;
252 	struct ucred *cred;
253 	struct proc *p;
254 {
255 
256 	return (ENXIO);
257 }
258 
259 /*
260  * Vnode op for read
261  */
262 /* ARGSUSED */
263 int
264 dead_read(vp, uio, ioflag, cred)
265 	struct vnode *vp;
266 	struct uio *uio;
267 	int ioflag;
268 	struct ucred *cred;
269 {
270 
271 	if (chkvnlock(vp))
272 		panic("dead_read: lock");
273 	/*
274 	 * Return EOF for character devices, EIO for others
275 	 */
276 	if (vp->v_type != VCHR)
277 		return (EIO);
278 	return (0);
279 }
280 
281 /*
282  * Vnode op for write
283  */
284 /* ARGSUSED */
285 int
286 dead_write(vp, uio, ioflag, cred)
287 	register struct vnode *vp;
288 	struct uio *uio;
289 	int ioflag;
290 	struct ucred *cred;
291 {
292 
293 	if (chkvnlock(vp))
294 		panic("dead_write: lock");
295 	return (EIO);
296 }
297 
298 /*
299  * Device ioctl operation.
300  */
301 /* ARGSUSED */
302 int
303 dead_ioctl(vp, com, data, fflag, cred, p)
304 	struct vnode *vp;
305 	register int com;
306 	caddr_t data;
307 	int fflag;
308 	struct ucred *cred;
309 	struct proc *p;
310 {
311 
312 	if (!chkvnlock(vp))
313 		return (EBADF);
314 	return (VOP_IOCTL(vp, com, data, fflag, cred, p));
315 }
316 
317 /* ARGSUSED */
318 int
319 dead_select(vp, which, fflags, cred, p)
320 	struct vnode *vp;
321 	int which, fflags;
322 	struct ucred *cred;
323 	struct proc *p;
324 {
325 
326 	/*
327 	 * Let the user find out that the descriptor is gone.
328 	 */
329 	return (1);
330 }
331 
332 /*
333  * Just call the device strategy routine
334  */
335 int
336 dead_strategy(bp)
337 	register struct buf *bp;
338 {
339 
340 	if (bp->b_vp == NULL || !chkvnlock(bp->b_vp)) {
341 		bp->b_flags |= B_ERROR;
342 		biodone(bp);
343 		return (EIO);
344 	}
345 	return (VOP_STRATEGY(bp));
346 }
347 
348 /*
349  * Wait until the vnode has finished changing state.
350  */
351 int
352 dead_lock(vp)
353 	struct vnode *vp;
354 {
355 
356 	if (!chkvnlock(vp))
357 		return (0);
358 	return (VOP_LOCK(vp));
359 }
360 
361 /*
362  * Wait until the vnode has finished changing state.
363  */
364 int
365 dead_bmap(vp, bn, vpp, bnp)
366 	struct vnode *vp;
367 	daddr_t bn;
368 	struct vnode **vpp;
369 	daddr_t *bnp;
370 {
371 
372 	if (!chkvnlock(vp))
373 		return (EIO);
374 	return (VOP_BMAP(vp, bn, vpp, bnp));
375 }
376 
377 /*
378  * Print out the contents of a dead vnode.
379  */
380 /* ARGSUSED */
381 void
382 dead_print(vp)
383 	struct vnode *vp;
384 {
385 
386 	printf("tag VT_NON, dead vnode\n");
387 }
388 
389 /*
390  * Empty vnode failed operation
391  */
392 int
393 dead_ebadf()
394 {
395 
396 	return (EBADF);
397 }
398 
399 /*
400  * Empty vnode bad operation
401  */
402 volatile void
403 dead_badop()
404 {
405 
406 	panic("dead_badop called");
407 	/* NOTREACHED */
408 }
409 
410 /*
411  * Empty vnode null operation
412  */
413 int
414 dead_nullop()
415 {
416 
417 	return (0);
418 }
419 
420 /*
421  * We have to wait during times when the vnode is
422  * in a state of change.
423  */
424 int
425 chkvnlock(vp)
426 	register struct vnode *vp;
427 {
428 	int locked = 0;
429 
430 	while (vp->v_flag & VXLOCK) {
431 		vp->v_flag |= VXWANT;
432 		tsleep((caddr_t)vp, PINOD, "chkvunlock", 0);
433 		locked = 1;
434 	}
435 	return (locked);
436 }
437