1/*
2 * Copyright (c) 1992, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * John Heidemann of the UCLA Ficus project.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)null_vnops.c 8.6 (Berkeley) 5/27/95
37 *
38 * Ancestors:
39 * @(#)lofs_vnops.c 1.2 (Berkeley) 6/18/92
| 1/*
2 * Copyright (c) 1992, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * John Heidemann of the UCLA Ficus project.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 *
36 * @(#)null_vnops.c 8.6 (Berkeley) 5/27/95
37 *
38 * Ancestors:
39 * @(#)lofs_vnops.c 1.2 (Berkeley) 6/18/92
|
40 * $Id: null_vnops.c,v 1.29 1998/07/04 20:45:33 julian Exp $
| 40 * $Id: null_vnops.c,v 1.30 1998/12/07 21:58:32 archie Exp $
|
41 * ...and...
42 * @(#)null_vnodeops.c 1.20 92/07/07 UCLA Ficus project
43 *
| 41 * ...and...
42 * @(#)null_vnodeops.c 1.20 92/07/07 UCLA Ficus project
43 *
|
44 * $Id: null_vnops.c,v 1.29 1998/07/04 20:45:33 julian Exp $
| 44 * $Id: null_vnops.c,v 1.30 1998/12/07 21:58:32 archie Exp $
|
45 */
46
47/*
48 * Null Layer
49 *
50 * (See mount_null(8) for more information.)
51 *
52 * The null layer duplicates a portion of the file system
53 * name space under a new name. In this respect, it is
54 * similar to the loopback file system. It differs from
55 * the loopback fs in two respects: it is implemented using
56 * a stackable layers techniques, and its "null-node"s stack above
57 * all lower-layer vnodes, not just over directory vnodes.
58 *
59 * The null layer has two purposes. First, it serves as a demonstration
60 * of layering by proving a layer which does nothing. (It actually
61 * does everything the loopback file system does, which is slightly
62 * more than nothing.) Second, the null layer can serve as a prototype
63 * layer. Since it provides all necessary layer framework,
64 * new file system layers can be created very easily be starting
65 * with a null layer.
66 *
67 * The remainder of this man page examines the null layer as a basis
68 * for constructing new layers.
69 *
70 *
71 * INSTANTIATING NEW NULL LAYERS
72 *
73 * New null layers are created with mount_null(8).
74 * Mount_null(8) takes two arguments, the pathname
75 * of the lower vfs (target-pn) and the pathname where the null
76 * layer will appear in the namespace (alias-pn). After
77 * the null layer is put into place, the contents
78 * of target-pn subtree will be aliased under alias-pn.
79 *
80 *
81 * OPERATION OF A NULL LAYER
82 *
83 * The null layer is the minimum file system layer,
84 * simply bypassing all possible operations to the lower layer
85 * for processing there. The majority of its activity centers
86 * on the bypass routine, through which nearly all vnode operations
87 * pass.
88 *
89 * The bypass routine accepts arbitrary vnode operations for
90 * handling by the lower layer. It begins by examing vnode
91 * operation arguments and replacing any null-nodes by their
92 * lower-layer equivlants. It then invokes the operation
93 * on the lower layer. Finally, it replaces the null-nodes
94 * in the arguments and, if a vnode is return by the operation,
95 * stacks a null-node on top of the returned vnode.
96 *
97 * Although bypass handles most operations, vop_getattr, vop_lock,
98 * vop_unlock, vop_inactive, vop_reclaim, and vop_print are not
99 * bypassed. Vop_getattr must change the fsid being returned.
100 * Vop_lock and vop_unlock must handle any locking for the
101 * current vnode as well as pass the lock request down.
102 * Vop_inactive and vop_reclaim are not bypassed so that
103 * they can handle freeing null-layer specific data. Vop_print
104 * is not bypassed to avoid excessive debugging information.
105 * Also, certain vnode operations change the locking state within
106 * the operation (create, mknod, remove, link, rename, mkdir, rmdir,
107 * and symlink). Ideally these operations should not change the
108 * lock state, but should be changed to let the caller of the
109 * function unlock them. Otherwise all intermediate vnode layers
110 * (such as union, umapfs, etc) must catch these functions to do
111 * the necessary locking at their layer.
112 *
113 *
114 * INSTANTIATING VNODE STACKS
115 *
116 * Mounting associates the null layer with a lower layer,
117 * effect stacking two VFSes. Vnode stacks are instead
118 * created on demand as files are accessed.
119 *
120 * The initial mount creates a single vnode stack for the
121 * root of the new null layer. All other vnode stacks
122 * are created as a result of vnode operations on
123 * this or other null vnode stacks.
124 *
125 * New vnode stacks come into existance as a result of
126 * an operation which returns a vnode.
127 * The bypass routine stacks a null-node above the new
128 * vnode before returning it to the caller.
129 *
130 * For example, imagine mounting a null layer with
131 * "mount_null /usr/include /dev/layer/null".
132 * Changing directory to /dev/layer/null will assign
133 * the root null-node (which was created when the null layer was mounted).
134 * Now consider opening "sys". A vop_lookup would be
135 * done on the root null-node. This operation would bypass through
136 * to the lower layer which would return a vnode representing
137 * the UFS "sys". Null_bypass then builds a null-node
138 * aliasing the UFS "sys" and returns this to the caller.
139 * Later operations on the null-node "sys" will repeat this
140 * process when constructing other vnode stacks.
141 *
142 *
143 * CREATING OTHER FILE SYSTEM LAYERS
144 *
145 * One of the easiest ways to construct new file system layers is to make
146 * a copy of the null layer, rename all files and variables, and
147 * then begin modifing the copy. Sed can be used to easily rename
148 * all variables.
149 *
150 * The umap layer is an example of a layer descended from the
151 * null layer.
152 *
153 *
154 * INVOKING OPERATIONS ON LOWER LAYERS
155 *
156 * There are two techniques to invoke operations on a lower layer
157 * when the operation cannot be completely bypassed. Each method
158 * is appropriate in different situations. In both cases,
159 * it is the responsibility of the aliasing layer to make
160 * the operation arguments "correct" for the lower layer
161 * by mapping an vnode arguments to the lower layer.
162 *
163 * The first approach is to call the aliasing layer's bypass routine.
164 * This method is most suitable when you wish to invoke the operation
165 * currently being handled on the lower layer. It has the advantage
166 * that the bypass routine already must do argument mapping.
167 * An example of this is null_getattrs in the null layer.
168 *
169 * A second approach is to directly invoke vnode operations on
170 * the lower layer with the VOP_OPERATIONNAME interface.
171 * The advantage of this method is that it is easy to invoke
172 * arbitrary operations on the lower layer. The disadvantage
173 * is that vnode arguments must be manualy mapped.
174 *
175 */
176
177#include "opt_debug_nullfs.h"
178
179#include <sys/param.h>
180#include <sys/systm.h>
181#include <sys/kernel.h>
182#include <sys/sysctl.h>
183#include <sys/vnode.h>
184#include <sys/mount.h>
185#include <sys/namei.h>
186#include <sys/malloc.h>
187#include <sys/buf.h>
188#include <miscfs/nullfs/null.h>
189
190static int null_bug_bypass = 0; /* for debugging: enables bypass printf'ing */
191SYSCTL_INT(_debug, OID_AUTO, nullfs_bug_bypass, CTLFLAG_RW,
192 &null_bug_bypass, 0, "");
193
194static int null_access __P((struct vop_access_args *ap));
195static int null_bwrite __P((struct vop_bwrite_args *ap));
196static int null_getattr __P((struct vop_getattr_args *ap));
197static int null_inactive __P((struct vop_inactive_args *ap));
198static int null_lock __P((struct vop_lock_args *ap));
199static int null_lookup __P((struct vop_lookup_args *ap));
200static int null_print __P((struct vop_print_args *ap));
201static int null_reclaim __P((struct vop_reclaim_args *ap));
202static int null_setattr __P((struct vop_setattr_args *ap));
203static int null_strategy __P((struct vop_strategy_args *ap));
204static int null_unlock __P((struct vop_unlock_args *ap));
205
206/*
207 * This is the 10-Apr-92 bypass routine.
208 * This version has been optimized for speed, throwing away some
209 * safety checks. It should still always work, but it's not as
210 * robust to programmer errors.
211 * Define SAFETY to include some error checking code.
212 *
213 * In general, we map all vnodes going down and unmap them on the way back.
214 * As an exception to this, vnodes can be marked "unmapped" by setting
215 * the Nth bit in operation's vdesc_flags.
216 *
217 * Also, some BSD vnode operations have the side effect of vrele'ing
218 * their arguments. With stacking, the reference counts are held
219 * by the upper node, not the lower one, so we must handle these
220 * side-effects here. This is not of concern in Sun-derived systems
221 * since there are no such side-effects.
222 *
223 * This makes the following assumptions:
224 * - only one returned vpp
225 * - no INOUT vpp's (Sun's vop_open has one of these)
226 * - the vnode operation vector of the first vnode should be used
227 * to determine what implementation of the op should be invoked
228 * - all mapped vnodes are of our vnode-type (NEEDSWORK:
229 * problems on rmdir'ing mount points and renaming?)
230 */
231int
232null_bypass(ap)
233 struct vop_generic_args /* {
234 struct vnodeop_desc *a_desc;
235 <other random data follows, presumably>
236 } */ *ap;
237{
238 register struct vnode **this_vp_p;
239 int error;
240 struct vnode *old_vps[VDESC_MAX_VPS];
241 struct vnode **vps_p[VDESC_MAX_VPS];
242 struct vnode ***vppp;
243 struct vnodeop_desc *descp = ap->a_desc;
244 int reles, i;
245
246 if (null_bug_bypass)
247 printf ("null_bypass: %s\n", descp->vdesc_name);
248
249#ifdef SAFETY
250 /*
251 * We require at least one vp.
252 */
253 if (descp->vdesc_vp_offsets == NULL ||
254 descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET)
255 panic ("null_bypass: no vp's in map.");
256#endif
257
258 /*
259 * Map the vnodes going in.
260 * Later, we'll invoke the operation based on
261 * the first mapped vnode's operation vector.
262 */
263 reles = descp->vdesc_flags;
264 for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
265 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
266 break; /* bail out at end of list */
267 vps_p[i] = this_vp_p =
268 VOPARG_OFFSETTO(struct vnode**,descp->vdesc_vp_offsets[i],ap);
269 /*
270 * We're not guaranteed that any but the first vnode
271 * are of our type. Check for and don't map any
272 * that aren't. (We must always map first vp or vclean fails.)
273 */
274 if (i && (*this_vp_p == NULLVP ||
275 (*this_vp_p)->v_op != null_vnodeop_p)) {
276 old_vps[i] = NULLVP;
277 } else {
278 old_vps[i] = *this_vp_p;
279 *(vps_p[i]) = NULLVPTOLOWERVP(*this_vp_p);
280 /*
281 * XXX - Several operations have the side effect
282 * of vrele'ing their vp's. We must account for
283 * that. (This should go away in the future.)
284 */
285 if (reles & 1)
286 VREF(*this_vp_p);
287 }
288
289 }
290
291 /*
292 * Call the operation on the lower layer
293 * with the modified argument structure.
294 */
295 error = VCALL(*(vps_p[0]), descp->vdesc_offset, ap);
296
297 /*
298 * Maintain the illusion of call-by-value
299 * by restoring vnodes in the argument structure
300 * to their original value.
301 */
302 reles = descp->vdesc_flags;
303 for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
304 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
305 break; /* bail out at end of list */
306 if (old_vps[i]) {
307 *(vps_p[i]) = old_vps[i];
308 if (reles & 1)
309 vrele(*(vps_p[i]));
310 }
311 }
312
313 /*
314 * Map the possible out-going vpp
315 * (Assumes that the lower layer always returns
316 * a VREF'ed vpp unless it gets an error.)
317 */
318 if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET &&
319 !(descp->vdesc_flags & VDESC_NOMAP_VPP) &&
320 !error) {
321 /*
322 * XXX - even though some ops have vpp returned vp's,
323 * several ops actually vrele this before returning.
324 * We must avoid these ops.
325 * (This should go away when these ops are regularized.)
326 */
327 if (descp->vdesc_flags & VDESC_VPP_WILLRELE)
328 goto out;
329 vppp = VOPARG_OFFSETTO(struct vnode***,
330 descp->vdesc_vpp_offset,ap);
331 if (*vppp)
332 error = null_node_create(old_vps[0]->v_mount, **vppp, *vppp);
333 }
334
335 out:
336 return (error);
337}
338
339/*
340 * We have to carry on the locking protocol on the null layer vnodes
341 * as we progress through the tree. We also have to enforce read-only
342 * if this layer is mounted read-only.
343 */
344static int
345null_lookup(ap)
346 struct vop_lookup_args /* {
347 struct vnode * a_dvp;
348 struct vnode ** a_vpp;
349 struct componentname * a_cnp;
350 } */ *ap;
351{
352 struct componentname *cnp = ap->a_cnp;
353 struct proc *p = cnp->cn_proc;
354 int flags = cnp->cn_flags;
355 struct vop_lock_args lockargs;
356 struct vop_unlock_args unlockargs;
357 struct vnode *dvp, *vp;
358 int error;
359
360 if ((flags & ISLASTCN) && (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) &&
361 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
362 return (EROFS);
363 error = null_bypass((struct vop_generic_args *)ap);
364 if (error == EJUSTRETURN && (flags & ISLASTCN) &&
365 (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) &&
366 (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME))
367 error = EROFS;
368 /*
369 * We must do the same locking and unlocking at this layer as
370 * is done in the layers below us. We could figure this out
371 * based on the error return and the LASTCN, LOCKPARENT, and
372 * LOCKLEAF flags. However, it is more expidient to just find
373 * out the state of the lower level vnodes and set ours to the
374 * same state.
375 */
376 dvp = ap->a_dvp;
377 vp = *ap->a_vpp;
378 if (dvp == vp)
379 return (error);
380 if (!VOP_ISLOCKED(dvp)) {
381 unlockargs.a_vp = dvp;
382 unlockargs.a_flags = 0;
383 unlockargs.a_p = p;
384 vop_nounlock(&unlockargs);
385 }
386 if (vp != NULLVP && VOP_ISLOCKED(vp)) {
387 lockargs.a_vp = vp;
388 lockargs.a_flags = LK_SHARED;
389 lockargs.a_p = p;
390 vop_nolock(&lockargs);
391 }
392 return (error);
393}
394
395/*
396 * Setattr call. Disallow write attempts if the layer is mounted read-only.
397 */
398int
399null_setattr(ap)
400 struct vop_setattr_args /* {
401 struct vnodeop_desc *a_desc;
402 struct vnode *a_vp;
403 struct vattr *a_vap;
404 struct ucred *a_cred;
405 struct proc *a_p;
406 } */ *ap;
407{
408 struct vnode *vp = ap->a_vp;
409 struct vattr *vap = ap->a_vap;
410
411 if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
412 vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
413 vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) &&
414 (vp->v_mount->mnt_flag & MNT_RDONLY))
415 return (EROFS);
416 if (vap->va_size != VNOVAL) {
417 switch (vp->v_type) {
418 case VDIR:
419 return (EISDIR);
420 case VCHR:
421 case VBLK:
422 case VSOCK:
423 case VFIFO:
424 if (vap->va_flags != VNOVAL)
425 return (EOPNOTSUPP);
426 return (0);
427 case VREG:
428 case VLNK:
429 default:
430 /*
431 * Disallow write attempts if the filesystem is
432 * mounted read-only.
433 */
434 if (vp->v_mount->mnt_flag & MNT_RDONLY)
435 return (EROFS);
436 }
437 }
438 return (null_bypass((struct vop_generic_args *)ap));
439}
440
441/*
442 * We handle getattr only to change the fsid.
443 */
444static int
445null_getattr(ap)
446 struct vop_getattr_args /* {
447 struct vnode *a_vp;
448 struct vattr *a_vap;
449 struct ucred *a_cred;
450 struct proc *a_p;
451 } */ *ap;
452{
453 int error;
454
455 if (error = null_bypass((struct vop_generic_args *)ap))
456 return (error);
457 /* Requires that arguments be restored. */
458 ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
459 return (0);
460}
461
462static int
463null_access(ap)
464 struct vop_access_args /* {
465 struct vnode *a_vp;
466 int a_mode;
467 struct ucred *a_cred;
468 struct proc *a_p;
469 } */ *ap;
470{
471 struct vnode *vp = ap->a_vp;
472 mode_t mode = ap->a_mode;
473
474 /*
475 * Disallow write attempts on read-only layers;
476 * unless the file is a socket, fifo, or a block or
477 * character device resident on the file system.
478 */
479 if (mode & VWRITE) {
480 switch (vp->v_type) {
481 case VDIR:
482 case VLNK:
483 case VREG:
484 if (vp->v_mount->mnt_flag & MNT_RDONLY)
485 return (EROFS);
486 break;
| 45 */
46
47/*
48 * Null Layer
49 *
50 * (See mount_null(8) for more information.)
51 *
52 * The null layer duplicates a portion of the file system
53 * name space under a new name. In this respect, it is
54 * similar to the loopback file system. It differs from
55 * the loopback fs in two respects: it is implemented using
56 * a stackable layers techniques, and its "null-node"s stack above
57 * all lower-layer vnodes, not just over directory vnodes.
58 *
59 * The null layer has two purposes. First, it serves as a demonstration
60 * of layering by proving a layer which does nothing. (It actually
61 * does everything the loopback file system does, which is slightly
62 * more than nothing.) Second, the null layer can serve as a prototype
63 * layer. Since it provides all necessary layer framework,
64 * new file system layers can be created very easily be starting
65 * with a null layer.
66 *
67 * The remainder of this man page examines the null layer as a basis
68 * for constructing new layers.
69 *
70 *
71 * INSTANTIATING NEW NULL LAYERS
72 *
73 * New null layers are created with mount_null(8).
74 * Mount_null(8) takes two arguments, the pathname
75 * of the lower vfs (target-pn) and the pathname where the null
76 * layer will appear in the namespace (alias-pn). After
77 * the null layer is put into place, the contents
78 * of target-pn subtree will be aliased under alias-pn.
79 *
80 *
81 * OPERATION OF A NULL LAYER
82 *
83 * The null layer is the minimum file system layer,
84 * simply bypassing all possible operations to the lower layer
85 * for processing there. The majority of its activity centers
86 * on the bypass routine, through which nearly all vnode operations
87 * pass.
88 *
89 * The bypass routine accepts arbitrary vnode operations for
90 * handling by the lower layer. It begins by examing vnode
91 * operation arguments and replacing any null-nodes by their
92 * lower-layer equivlants. It then invokes the operation
93 * on the lower layer. Finally, it replaces the null-nodes
94 * in the arguments and, if a vnode is return by the operation,
95 * stacks a null-node on top of the returned vnode.
96 *
97 * Although bypass handles most operations, vop_getattr, vop_lock,
98 * vop_unlock, vop_inactive, vop_reclaim, and vop_print are not
99 * bypassed. Vop_getattr must change the fsid being returned.
100 * Vop_lock and vop_unlock must handle any locking for the
101 * current vnode as well as pass the lock request down.
102 * Vop_inactive and vop_reclaim are not bypassed so that
103 * they can handle freeing null-layer specific data. Vop_print
104 * is not bypassed to avoid excessive debugging information.
105 * Also, certain vnode operations change the locking state within
106 * the operation (create, mknod, remove, link, rename, mkdir, rmdir,
107 * and symlink). Ideally these operations should not change the
108 * lock state, but should be changed to let the caller of the
109 * function unlock them. Otherwise all intermediate vnode layers
110 * (such as union, umapfs, etc) must catch these functions to do
111 * the necessary locking at their layer.
112 *
113 *
114 * INSTANTIATING VNODE STACKS
115 *
116 * Mounting associates the null layer with a lower layer,
117 * effect stacking two VFSes. Vnode stacks are instead
118 * created on demand as files are accessed.
119 *
120 * The initial mount creates a single vnode stack for the
121 * root of the new null layer. All other vnode stacks
122 * are created as a result of vnode operations on
123 * this or other null vnode stacks.
124 *
125 * New vnode stacks come into existance as a result of
126 * an operation which returns a vnode.
127 * The bypass routine stacks a null-node above the new
128 * vnode before returning it to the caller.
129 *
130 * For example, imagine mounting a null layer with
131 * "mount_null /usr/include /dev/layer/null".
132 * Changing directory to /dev/layer/null will assign
133 * the root null-node (which was created when the null layer was mounted).
134 * Now consider opening "sys". A vop_lookup would be
135 * done on the root null-node. This operation would bypass through
136 * to the lower layer which would return a vnode representing
137 * the UFS "sys". Null_bypass then builds a null-node
138 * aliasing the UFS "sys" and returns this to the caller.
139 * Later operations on the null-node "sys" will repeat this
140 * process when constructing other vnode stacks.
141 *
142 *
143 * CREATING OTHER FILE SYSTEM LAYERS
144 *
145 * One of the easiest ways to construct new file system layers is to make
146 * a copy of the null layer, rename all files and variables, and
147 * then begin modifing the copy. Sed can be used to easily rename
148 * all variables.
149 *
150 * The umap layer is an example of a layer descended from the
151 * null layer.
152 *
153 *
154 * INVOKING OPERATIONS ON LOWER LAYERS
155 *
156 * There are two techniques to invoke operations on a lower layer
157 * when the operation cannot be completely bypassed. Each method
158 * is appropriate in different situations. In both cases,
159 * it is the responsibility of the aliasing layer to make
160 * the operation arguments "correct" for the lower layer
161 * by mapping an vnode arguments to the lower layer.
162 *
163 * The first approach is to call the aliasing layer's bypass routine.
164 * This method is most suitable when you wish to invoke the operation
165 * currently being handled on the lower layer. It has the advantage
166 * that the bypass routine already must do argument mapping.
167 * An example of this is null_getattrs in the null layer.
168 *
169 * A second approach is to directly invoke vnode operations on
170 * the lower layer with the VOP_OPERATIONNAME interface.
171 * The advantage of this method is that it is easy to invoke
172 * arbitrary operations on the lower layer. The disadvantage
173 * is that vnode arguments must be manualy mapped.
174 *
175 */
176
177#include "opt_debug_nullfs.h"
178
179#include <sys/param.h>
180#include <sys/systm.h>
181#include <sys/kernel.h>
182#include <sys/sysctl.h>
183#include <sys/vnode.h>
184#include <sys/mount.h>
185#include <sys/namei.h>
186#include <sys/malloc.h>
187#include <sys/buf.h>
188#include <miscfs/nullfs/null.h>
189
190static int null_bug_bypass = 0; /* for debugging: enables bypass printf'ing */
191SYSCTL_INT(_debug, OID_AUTO, nullfs_bug_bypass, CTLFLAG_RW,
192 &null_bug_bypass, 0, "");
193
194static int null_access __P((struct vop_access_args *ap));
195static int null_bwrite __P((struct vop_bwrite_args *ap));
196static int null_getattr __P((struct vop_getattr_args *ap));
197static int null_inactive __P((struct vop_inactive_args *ap));
198static int null_lock __P((struct vop_lock_args *ap));
199static int null_lookup __P((struct vop_lookup_args *ap));
200static int null_print __P((struct vop_print_args *ap));
201static int null_reclaim __P((struct vop_reclaim_args *ap));
202static int null_setattr __P((struct vop_setattr_args *ap));
203static int null_strategy __P((struct vop_strategy_args *ap));
204static int null_unlock __P((struct vop_unlock_args *ap));
205
206/*
207 * This is the 10-Apr-92 bypass routine.
208 * This version has been optimized for speed, throwing away some
209 * safety checks. It should still always work, but it's not as
210 * robust to programmer errors.
211 * Define SAFETY to include some error checking code.
212 *
213 * In general, we map all vnodes going down and unmap them on the way back.
214 * As an exception to this, vnodes can be marked "unmapped" by setting
215 * the Nth bit in operation's vdesc_flags.
216 *
217 * Also, some BSD vnode operations have the side effect of vrele'ing
218 * their arguments. With stacking, the reference counts are held
219 * by the upper node, not the lower one, so we must handle these
220 * side-effects here. This is not of concern in Sun-derived systems
221 * since there are no such side-effects.
222 *
223 * This makes the following assumptions:
224 * - only one returned vpp
225 * - no INOUT vpp's (Sun's vop_open has one of these)
226 * - the vnode operation vector of the first vnode should be used
227 * to determine what implementation of the op should be invoked
228 * - all mapped vnodes are of our vnode-type (NEEDSWORK:
229 * problems on rmdir'ing mount points and renaming?)
230 */
231int
232null_bypass(ap)
233 struct vop_generic_args /* {
234 struct vnodeop_desc *a_desc;
235 <other random data follows, presumably>
236 } */ *ap;
237{
238 register struct vnode **this_vp_p;
239 int error;
240 struct vnode *old_vps[VDESC_MAX_VPS];
241 struct vnode **vps_p[VDESC_MAX_VPS];
242 struct vnode ***vppp;
243 struct vnodeop_desc *descp = ap->a_desc;
244 int reles, i;
245
246 if (null_bug_bypass)
247 printf ("null_bypass: %s\n", descp->vdesc_name);
248
249#ifdef SAFETY
250 /*
251 * We require at least one vp.
252 */
253 if (descp->vdesc_vp_offsets == NULL ||
254 descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET)
255 panic ("null_bypass: no vp's in map.");
256#endif
257
258 /*
259 * Map the vnodes going in.
260 * Later, we'll invoke the operation based on
261 * the first mapped vnode's operation vector.
262 */
263 reles = descp->vdesc_flags;
264 for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
265 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
266 break; /* bail out at end of list */
267 vps_p[i] = this_vp_p =
268 VOPARG_OFFSETTO(struct vnode**,descp->vdesc_vp_offsets[i],ap);
269 /*
270 * We're not guaranteed that any but the first vnode
271 * are of our type. Check for and don't map any
272 * that aren't. (We must always map first vp or vclean fails.)
273 */
274 if (i && (*this_vp_p == NULLVP ||
275 (*this_vp_p)->v_op != null_vnodeop_p)) {
276 old_vps[i] = NULLVP;
277 } else {
278 old_vps[i] = *this_vp_p;
279 *(vps_p[i]) = NULLVPTOLOWERVP(*this_vp_p);
280 /*
281 * XXX - Several operations have the side effect
282 * of vrele'ing their vp's. We must account for
283 * that. (This should go away in the future.)
284 */
285 if (reles & 1)
286 VREF(*this_vp_p);
287 }
288
289 }
290
291 /*
292 * Call the operation on the lower layer
293 * with the modified argument structure.
294 */
295 error = VCALL(*(vps_p[0]), descp->vdesc_offset, ap);
296
297 /*
298 * Maintain the illusion of call-by-value
299 * by restoring vnodes in the argument structure
300 * to their original value.
301 */
302 reles = descp->vdesc_flags;
303 for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
304 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
305 break; /* bail out at end of list */
306 if (old_vps[i]) {
307 *(vps_p[i]) = old_vps[i];
308 if (reles & 1)
309 vrele(*(vps_p[i]));
310 }
311 }
312
313 /*
314 * Map the possible out-going vpp
315 * (Assumes that the lower layer always returns
316 * a VREF'ed vpp unless it gets an error.)
317 */
318 if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET &&
319 !(descp->vdesc_flags & VDESC_NOMAP_VPP) &&
320 !error) {
321 /*
322 * XXX - even though some ops have vpp returned vp's,
323 * several ops actually vrele this before returning.
324 * We must avoid these ops.
325 * (This should go away when these ops are regularized.)
326 */
327 if (descp->vdesc_flags & VDESC_VPP_WILLRELE)
328 goto out;
329 vppp = VOPARG_OFFSETTO(struct vnode***,
330 descp->vdesc_vpp_offset,ap);
331 if (*vppp)
332 error = null_node_create(old_vps[0]->v_mount, **vppp, *vppp);
333 }
334
335 out:
336 return (error);
337}
338
339/*
340 * We have to carry on the locking protocol on the null layer vnodes
341 * as we progress through the tree. We also have to enforce read-only
342 * if this layer is mounted read-only.
343 */
344static int
345null_lookup(ap)
346 struct vop_lookup_args /* {
347 struct vnode * a_dvp;
348 struct vnode ** a_vpp;
349 struct componentname * a_cnp;
350 } */ *ap;
351{
352 struct componentname *cnp = ap->a_cnp;
353 struct proc *p = cnp->cn_proc;
354 int flags = cnp->cn_flags;
355 struct vop_lock_args lockargs;
356 struct vop_unlock_args unlockargs;
357 struct vnode *dvp, *vp;
358 int error;
359
360 if ((flags & ISLASTCN) && (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) &&
361 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
362 return (EROFS);
363 error = null_bypass((struct vop_generic_args *)ap);
364 if (error == EJUSTRETURN && (flags & ISLASTCN) &&
365 (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) &&
366 (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME))
367 error = EROFS;
368 /*
369 * We must do the same locking and unlocking at this layer as
370 * is done in the layers below us. We could figure this out
371 * based on the error return and the LASTCN, LOCKPARENT, and
372 * LOCKLEAF flags. However, it is more expidient to just find
373 * out the state of the lower level vnodes and set ours to the
374 * same state.
375 */
376 dvp = ap->a_dvp;
377 vp = *ap->a_vpp;
378 if (dvp == vp)
379 return (error);
380 if (!VOP_ISLOCKED(dvp)) {
381 unlockargs.a_vp = dvp;
382 unlockargs.a_flags = 0;
383 unlockargs.a_p = p;
384 vop_nounlock(&unlockargs);
385 }
386 if (vp != NULLVP && VOP_ISLOCKED(vp)) {
387 lockargs.a_vp = vp;
388 lockargs.a_flags = LK_SHARED;
389 lockargs.a_p = p;
390 vop_nolock(&lockargs);
391 }
392 return (error);
393}
394
395/*
396 * Setattr call. Disallow write attempts if the layer is mounted read-only.
397 */
398int
399null_setattr(ap)
400 struct vop_setattr_args /* {
401 struct vnodeop_desc *a_desc;
402 struct vnode *a_vp;
403 struct vattr *a_vap;
404 struct ucred *a_cred;
405 struct proc *a_p;
406 } */ *ap;
407{
408 struct vnode *vp = ap->a_vp;
409 struct vattr *vap = ap->a_vap;
410
411 if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
412 vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
413 vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) &&
414 (vp->v_mount->mnt_flag & MNT_RDONLY))
415 return (EROFS);
416 if (vap->va_size != VNOVAL) {
417 switch (vp->v_type) {
418 case VDIR:
419 return (EISDIR);
420 case VCHR:
421 case VBLK:
422 case VSOCK:
423 case VFIFO:
424 if (vap->va_flags != VNOVAL)
425 return (EOPNOTSUPP);
426 return (0);
427 case VREG:
428 case VLNK:
429 default:
430 /*
431 * Disallow write attempts if the filesystem is
432 * mounted read-only.
433 */
434 if (vp->v_mount->mnt_flag & MNT_RDONLY)
435 return (EROFS);
436 }
437 }
438 return (null_bypass((struct vop_generic_args *)ap));
439}
440
441/*
442 * We handle getattr only to change the fsid.
443 */
444static int
445null_getattr(ap)
446 struct vop_getattr_args /* {
447 struct vnode *a_vp;
448 struct vattr *a_vap;
449 struct ucred *a_cred;
450 struct proc *a_p;
451 } */ *ap;
452{
453 int error;
454
455 if (error = null_bypass((struct vop_generic_args *)ap))
456 return (error);
457 /* Requires that arguments be restored. */
458 ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
459 return (0);
460}
461
462static int
463null_access(ap)
464 struct vop_access_args /* {
465 struct vnode *a_vp;
466 int a_mode;
467 struct ucred *a_cred;
468 struct proc *a_p;
469 } */ *ap;
470{
471 struct vnode *vp = ap->a_vp;
472 mode_t mode = ap->a_mode;
473
474 /*
475 * Disallow write attempts on read-only layers;
476 * unless the file is a socket, fifo, or a block or
477 * character device resident on the file system.
478 */
479 if (mode & VWRITE) {
480 switch (vp->v_type) {
481 case VDIR:
482 case VLNK:
483 case VREG:
484 if (vp->v_mount->mnt_flag & MNT_RDONLY)
485 return (EROFS);
486 break;
|
| 487 default:
488 break;
|
487 }
488 }
489 return (null_bypass((struct vop_generic_args *)ap));
490}
491
492/*
493 * We need to process our own vnode lock and then clear the
494 * interlock flag as it applies only to our vnode, not the
495 * vnodes below us on the stack.
496 */
497static int
498null_lock(ap)
499 struct vop_lock_args /* {
500 struct vnode *a_vp;
501 int a_flags;
502 struct proc *a_p;
503 } */ *ap;
504{
505
506 vop_nolock(ap);
507 if ((ap->a_flags & LK_TYPE_MASK) == LK_DRAIN)
508 return (0);
509 ap->a_flags &= ~LK_INTERLOCK;
510 return (null_bypass((struct vop_generic_args *)ap));
511}
512
513/*
514 * We need to process our own vnode unlock and then clear the
515 * interlock flag as it applies only to our vnode, not the
516 * vnodes below us on the stack.
517 */
518static int
519null_unlock(ap)
520 struct vop_unlock_args /* {
521 struct vnode *a_vp;
522 int a_flags;
523 struct proc *a_p;
524 } */ *ap;
525{
526 vop_nounlock(ap);
527 ap->a_flags &= ~LK_INTERLOCK;
528 return (null_bypass((struct vop_generic_args *)ap));
529}
530
531static int
532null_inactive(ap)
533 struct vop_inactive_args /* {
534 struct vnode *a_vp;
535 struct proc *a_p;
536 } */ *ap;
537{
538 struct vnode *vp = ap->a_vp;
539 struct null_node *xp = VTONULL(vp);
540 struct vnode *lowervp = xp->null_lowervp;
541 /*
542 * Do nothing (and _don't_ bypass).
543 * Wait to vrele lowervp until reclaim,
544 * so that until then our null_node is in the
545 * cache and reusable.
546 * We still have to tell the lower layer the vnode
547 * is now inactive though.
548 *
549 * NEEDSWORK: Someday, consider inactive'ing
550 * the lowervp and then trying to reactivate it
551 * with capabilities (v_id)
552 * like they do in the name lookup cache code.
553 * That's too much work for now.
554 */
555 VOP_INACTIVE(lowervp, ap->a_p);
556 VOP_UNLOCK(ap->a_vp, 0, ap->a_p);
557 return (0);
558}
559
560static int
561null_reclaim(ap)
562 struct vop_reclaim_args /* {
563 struct vnode *a_vp;
564 struct proc *a_p;
565 } */ *ap;
566{
567 struct vnode *vp = ap->a_vp;
568 struct null_node *xp = VTONULL(vp);
569 struct vnode *lowervp = xp->null_lowervp;
570
571 /*
572 * Note: in vop_reclaim, vp->v_op == dead_vnodeop_p,
573 * so we can't call VOPs on ourself.
574 */
575 /* After this assignment, this node will not be re-used. */
576 xp->null_lowervp = NULLVP;
577 LIST_REMOVE(xp, null_hash);
578 FREE(vp->v_data, M_TEMP);
579 vp->v_data = NULL;
580 vrele (lowervp);
581 return (0);
582}
583
584static int
585null_print(ap)
586 struct vop_print_args /* {
587 struct vnode *a_vp;
588 } */ *ap;
589{
590 register struct vnode *vp = ap->a_vp;
591 printf ("\ttag VT_NULLFS, vp=%p, lowervp=%p\n", vp, NULLVPTOLOWERVP(vp));
592 return (0);
593}
594
595/*
596 * XXX - vop_strategy must be hand coded because it has no
597 * vnode in its arguments.
598 * This goes away with a merged VM/buffer cache.
599 */
600static int
601null_strategy(ap)
602 struct vop_strategy_args /* {
603 struct buf *a_bp;
604 } */ *ap;
605{
606 struct buf *bp = ap->a_bp;
607 int error;
608 struct vnode *savedvp;
609
610 savedvp = bp->b_vp;
611 bp->b_vp = NULLVPTOLOWERVP(bp->b_vp);
612
613 error = VOP_STRATEGY(bp->b_vp, bp);
614
615 bp->b_vp = savedvp;
616
617 return (error);
618}
619
620/*
621 * XXX - like vop_strategy, vop_bwrite must be hand coded because it has no
622 * vnode in its arguments.
623 * This goes away with a merged VM/buffer cache.
624 */
625static int
626null_bwrite(ap)
627 struct vop_bwrite_args /* {
628 struct buf *a_bp;
629 } */ *ap;
630{
631 struct buf *bp = ap->a_bp;
632 int error;
633 struct vnode *savedvp;
634
635 savedvp = bp->b_vp;
636 bp->b_vp = NULLVPTOLOWERVP(bp->b_vp);
637
638 error = VOP_BWRITE(bp);
639
640 bp->b_vp = savedvp;
641
642 return (error);
643}
644
645/*
646 * Global vfs data structures
647 */
648vop_t **null_vnodeop_p;
649static struct vnodeopv_entry_desc null_vnodeop_entries[] = {
650 { &vop_default_desc, (vop_t *) null_bypass },
651 { &vop_access_desc, (vop_t *) null_access },
652 { &vop_bwrite_desc, (vop_t *) null_bwrite },
653 { &vop_getattr_desc, (vop_t *) null_getattr },
654 { &vop_inactive_desc, (vop_t *) null_inactive },
655 { &vop_lock_desc, (vop_t *) null_lock },
656 { &vop_lookup_desc, (vop_t *) null_lookup },
657 { &vop_print_desc, (vop_t *) null_print },
658 { &vop_reclaim_desc, (vop_t *) null_reclaim },
659 { &vop_setattr_desc, (vop_t *) null_setattr },
660 { &vop_strategy_desc, (vop_t *) null_strategy },
661 { &vop_unlock_desc, (vop_t *) null_unlock },
662 { NULL, NULL }
663};
664static struct vnodeopv_desc null_vnodeop_opv_desc =
665 { &null_vnodeop_p, null_vnodeop_entries };
666
667VNODEOP_SET(null_vnodeop_opv_desc);
| 489 }
490 }
491 return (null_bypass((struct vop_generic_args *)ap));
492}
493
494/*
495 * We need to process our own vnode lock and then clear the
496 * interlock flag as it applies only to our vnode, not the
497 * vnodes below us on the stack.
498 */
499static int
500null_lock(ap)
501 struct vop_lock_args /* {
502 struct vnode *a_vp;
503 int a_flags;
504 struct proc *a_p;
505 } */ *ap;
506{
507
508 vop_nolock(ap);
509 if ((ap->a_flags & LK_TYPE_MASK) == LK_DRAIN)
510 return (0);
511 ap->a_flags &= ~LK_INTERLOCK;
512 return (null_bypass((struct vop_generic_args *)ap));
513}
514
515/*
516 * We need to process our own vnode unlock and then clear the
517 * interlock flag as it applies only to our vnode, not the
518 * vnodes below us on the stack.
519 */
520static int
521null_unlock(ap)
522 struct vop_unlock_args /* {
523 struct vnode *a_vp;
524 int a_flags;
525 struct proc *a_p;
526 } */ *ap;
527{
528 vop_nounlock(ap);
529 ap->a_flags &= ~LK_INTERLOCK;
530 return (null_bypass((struct vop_generic_args *)ap));
531}
532
533static int
534null_inactive(ap)
535 struct vop_inactive_args /* {
536 struct vnode *a_vp;
537 struct proc *a_p;
538 } */ *ap;
539{
540 struct vnode *vp = ap->a_vp;
541 struct null_node *xp = VTONULL(vp);
542 struct vnode *lowervp = xp->null_lowervp;
543 /*
544 * Do nothing (and _don't_ bypass).
545 * Wait to vrele lowervp until reclaim,
546 * so that until then our null_node is in the
547 * cache and reusable.
548 * We still have to tell the lower layer the vnode
549 * is now inactive though.
550 *
551 * NEEDSWORK: Someday, consider inactive'ing
552 * the lowervp and then trying to reactivate it
553 * with capabilities (v_id)
554 * like they do in the name lookup cache code.
555 * That's too much work for now.
556 */
557 VOP_INACTIVE(lowervp, ap->a_p);
558 VOP_UNLOCK(ap->a_vp, 0, ap->a_p);
559 return (0);
560}
561
562static int
563null_reclaim(ap)
564 struct vop_reclaim_args /* {
565 struct vnode *a_vp;
566 struct proc *a_p;
567 } */ *ap;
568{
569 struct vnode *vp = ap->a_vp;
570 struct null_node *xp = VTONULL(vp);
571 struct vnode *lowervp = xp->null_lowervp;
572
573 /*
574 * Note: in vop_reclaim, vp->v_op == dead_vnodeop_p,
575 * so we can't call VOPs on ourself.
576 */
577 /* After this assignment, this node will not be re-used. */
578 xp->null_lowervp = NULLVP;
579 LIST_REMOVE(xp, null_hash);
580 FREE(vp->v_data, M_TEMP);
581 vp->v_data = NULL;
582 vrele (lowervp);
583 return (0);
584}
585
586static int
587null_print(ap)
588 struct vop_print_args /* {
589 struct vnode *a_vp;
590 } */ *ap;
591{
592 register struct vnode *vp = ap->a_vp;
593 printf ("\ttag VT_NULLFS, vp=%p, lowervp=%p\n", vp, NULLVPTOLOWERVP(vp));
594 return (0);
595}
596
597/*
598 * XXX - vop_strategy must be hand coded because it has no
599 * vnode in its arguments.
600 * This goes away with a merged VM/buffer cache.
601 */
602static int
603null_strategy(ap)
604 struct vop_strategy_args /* {
605 struct buf *a_bp;
606 } */ *ap;
607{
608 struct buf *bp = ap->a_bp;
609 int error;
610 struct vnode *savedvp;
611
612 savedvp = bp->b_vp;
613 bp->b_vp = NULLVPTOLOWERVP(bp->b_vp);
614
615 error = VOP_STRATEGY(bp->b_vp, bp);
616
617 bp->b_vp = savedvp;
618
619 return (error);
620}
621
622/*
623 * XXX - like vop_strategy, vop_bwrite must be hand coded because it has no
624 * vnode in its arguments.
625 * This goes away with a merged VM/buffer cache.
626 */
627static int
628null_bwrite(ap)
629 struct vop_bwrite_args /* {
630 struct buf *a_bp;
631 } */ *ap;
632{
633 struct buf *bp = ap->a_bp;
634 int error;
635 struct vnode *savedvp;
636
637 savedvp = bp->b_vp;
638 bp->b_vp = NULLVPTOLOWERVP(bp->b_vp);
639
640 error = VOP_BWRITE(bp);
641
642 bp->b_vp = savedvp;
643
644 return (error);
645}
646
647/*
648 * Global vfs data structures
649 */
650vop_t **null_vnodeop_p;
651static struct vnodeopv_entry_desc null_vnodeop_entries[] = {
652 { &vop_default_desc, (vop_t *) null_bypass },
653 { &vop_access_desc, (vop_t *) null_access },
654 { &vop_bwrite_desc, (vop_t *) null_bwrite },
655 { &vop_getattr_desc, (vop_t *) null_getattr },
656 { &vop_inactive_desc, (vop_t *) null_inactive },
657 { &vop_lock_desc, (vop_t *) null_lock },
658 { &vop_lookup_desc, (vop_t *) null_lookup },
659 { &vop_print_desc, (vop_t *) null_print },
660 { &vop_reclaim_desc, (vop_t *) null_reclaim },
661 { &vop_setattr_desc, (vop_t *) null_setattr },
662 { &vop_strategy_desc, (vop_t *) null_strategy },
663 { &vop_unlock_desc, (vop_t *) null_unlock },
664 { NULL, NULL }
665};
666static struct vnodeopv_desc null_vnodeop_opv_desc =
667 { &null_vnodeop_p, null_vnodeop_entries };
668
669VNODEOP_SET(null_vnodeop_opv_desc);
|