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 1.13 1997/02/10 02:13:30 dyson Exp $
| 40 * $Id: null_vnops.c,v 1.14 1997/02/12 14:55:01 mpp 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 * $FreeBSD: head/sys/fs/nullfs/null_vnops.c 22597 1997-02-12 14:55:01Z mpp $
| 44 * $FreeBSD: head/sys/fs/nullfs/null_vnops.c 22607 1997-02-12 18:06:08Z mpp $
|
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 it's "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, though 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 hanldled 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 invoked 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 vnodes arguments must be manualy mapped.
174 *
175 */
176
177#include <sys/param.h>
178#include <sys/systm.h>
179#include <sys/kernel.h>
180#include <sys/sysctl.h>
181#include <sys/proc.h>
182#include <sys/time.h>
183#include <sys/types.h>
184#include <sys/vnode.h>
185#include <sys/mount.h>
186#include <sys/namei.h>
187#include <sys/malloc.h>
188#include <sys/buf.h>
189#include <miscfs/nullfs/null.h>
190
191static int null_bug_bypass = 0; /* for debugging: enables bypass printf'ing */
192SYSCTL_INT(_debug, OID_AUTO, nullfs_bug_bypass, CTLFLAG_RW,
193 &null_bug_bypass, 0, "");
194
195static int null_access __P((struct vop_access_args *ap));
196int null_bypass __P((struct vop_generic_args *ap));
197static int null_bwrite __P((struct vop_bwrite_args *ap));
198static int null_getattr __P((struct vop_getattr_args *ap));
199static int null_inactive __P((struct vop_inactive_args *ap));
200static int null_lock __P((struct vop_lock_args *ap));
201static int null_lookup __P((struct vop_lookup_args *ap));
202static int null_print __P((struct vop_print_args *ap));
203static int null_reclaim __P((struct vop_reclaim_args *ap));
204static int null_setattr __P((struct vop_setattr_args *ap));
205static int null_strategy __P((struct vop_strategy_args *ap));
206static int null_unlock __P((struct vop_unlock_args *ap));
207
208/*
209 * This is the 10-Apr-92 bypass routine.
210 * This version has been optimized for speed, throwing away some
211 * safety checks. It should still always work, but it's not as
212 * robust to programmer errors.
213 * Define SAFETY to include some error checking code.
214 *
215 * In general, we map all vnodes going down and unmap them on the way back.
216 * As an exception to this, vnodes can be marked "unmapped" by setting
217 * the Nth bit in operation's vdesc_flags.
218 *
219 * Also, some BSD vnode operations have the side effect of vrele'ing
220 * their arguments. With stacking, the reference counts are held
221 * by the upper node, not the lower one, so we must handle these
222 * side-effects here. This is not of concern in Sun-derived systems
223 * since there are no such side-effects.
224 *
225 * This makes the following assumptions:
226 * - only one returned vpp
227 * - no INOUT vpp's (Sun's vop_open has one of these)
228 * - the vnode operation vector of the first vnode should be used
229 * to determine what implementation of the op should be invoked
230 * - all mapped vnodes are of our vnode-type (NEEDSWORK:
231 * problems on rmdir'ing mount points and renaming?)
232 */
233int
234null_bypass(ap)
235 struct vop_generic_args /* {
236 struct vnodeop_desc *a_desc;
237 <other random data follows, presumably>
238 } */ *ap;
239{
240 register struct vnode **this_vp_p;
241 int error;
242 struct vnode *old_vps[VDESC_MAX_VPS];
243 struct vnode **vps_p[VDESC_MAX_VPS];
244 struct vnode ***vppp;
245 struct vnodeop_desc *descp = ap->a_desc;
246 int reles, i;
247
248 if (null_bug_bypass)
249 printf ("null_bypass: %s\n", descp->vdesc_name);
250
251#ifdef SAFETY
252 /*
253 * We require at least one vp.
254 */
255 if (descp->vdesc_vp_offsets == NULL ||
256 descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET)
257 panic ("null_bypass: no vp's in map.");
258#endif
259
260 /*
261 * Map the vnodes going in.
262 * Later, we'll invoke the operation based on
263 * the first mapped vnode's operation vector.
264 */
265 reles = descp->vdesc_flags;
266 for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
267 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
268 break; /* bail out at end of list */
269 vps_p[i] = this_vp_p =
270 VOPARG_OFFSETTO(struct vnode**,descp->vdesc_vp_offsets[i],ap);
271 /*
272 * We're not guaranteed that any but the first vnode
273 * are of our type. Check for and don't map any
274 * that aren't. (We must always map first vp or vclean fails.)
275 */
276 if (i && (*this_vp_p == NULL ||
277 (*this_vp_p)->v_op != null_vnodeop_p)) {
278 old_vps[i] = NULL;
279 } else {
280 old_vps[i] = *this_vp_p;
281 *(vps_p[i]) = NULLVPTOLOWERVP(*this_vp_p);
282 /*
283 * XXX - Several operations have the side effect
284 * of vrele'ing their vp's. We must account for
285 * that. (This should go away in the future.)
286 */
287 if (reles & 1)
288 VREF(*this_vp_p);
289 }
290
291 }
292
293 /*
294 * Call the operation on the lower layer
295 * with the modified argument structure.
296 */
297 error = VCALL(*(vps_p[0]), descp->vdesc_offset, ap);
298
299 /*
300 * Maintain the illusion of call-by-value
301 * by restoring vnodes in the argument structure
302 * to their original value.
303 */
304 reles = descp->vdesc_flags;
305 for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
306 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
307 break; /* bail out at end of list */
308 if (old_vps[i]) {
309 *(vps_p[i]) = old_vps[i];
310 if (reles & 1)
311 vrele(*(vps_p[i]));
312 }
313 }
314
315 /*
316 * Map the possible out-going vpp
317 * (Assumes that the lower layer always returns
318 * a VREF'ed vpp unless it gets an error.)
319 */
320 if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET &&
321 !(descp->vdesc_flags & VDESC_NOMAP_VPP) &&
322 !error) {
323 /*
324 * XXX - even though some ops have vpp returned vp's,
325 * several ops actually vrele this before returning.
326 * We must avoid these ops.
327 * (This should go away when these ops are regularized.)
328 */
329 if (descp->vdesc_flags & VDESC_VPP_WILLRELE)
330 goto out;
331 vppp = VOPARG_OFFSETTO(struct vnode***,
332 descp->vdesc_vpp_offset,ap);
333 error = null_node_create(old_vps[0]->v_mount, **vppp, *vppp);
334 }
335
336 out:
337 return (error);
338}
339
340/*
341 * We have to carry on the locking protocol on the null layer vnodes
342 * as we progress through the tree. We also have to enforce read-only
343 * if this layer is mounted read-only.
344 */
345static int
346null_lookup(ap)
347 struct vop_lookup_args /* {
348 struct vnode * a_dvp;
349 struct vnode ** a_vpp;
350 struct componentname * a_cnp;
351 } */ *ap;
352{
353 struct componentname *cnp = ap->a_cnp;
354 struct proc *p = cnp->cn_proc;
355 int flags = cnp->cn_flags;
356 struct vop_lock_args lockargs;
357 struct vop_unlock_args unlockargs;
358 struct vnode *dvp, *vp;
359 int error;
360
361 if ((flags & ISLASTCN) && (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) &&
362 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
363 return (EROFS);
| 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 it's "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, though 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 hanldled 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 invoked 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 vnodes arguments must be manualy mapped.
174 *
175 */
176
177#include <sys/param.h>
178#include <sys/systm.h>
179#include <sys/kernel.h>
180#include <sys/sysctl.h>
181#include <sys/proc.h>
182#include <sys/time.h>
183#include <sys/types.h>
184#include <sys/vnode.h>
185#include <sys/mount.h>
186#include <sys/namei.h>
187#include <sys/malloc.h>
188#include <sys/buf.h>
189#include <miscfs/nullfs/null.h>
190
191static int null_bug_bypass = 0; /* for debugging: enables bypass printf'ing */
192SYSCTL_INT(_debug, OID_AUTO, nullfs_bug_bypass, CTLFLAG_RW,
193 &null_bug_bypass, 0, "");
194
195static int null_access __P((struct vop_access_args *ap));
196int null_bypass __P((struct vop_generic_args *ap));
197static int null_bwrite __P((struct vop_bwrite_args *ap));
198static int null_getattr __P((struct vop_getattr_args *ap));
199static int null_inactive __P((struct vop_inactive_args *ap));
200static int null_lock __P((struct vop_lock_args *ap));
201static int null_lookup __P((struct vop_lookup_args *ap));
202static int null_print __P((struct vop_print_args *ap));
203static int null_reclaim __P((struct vop_reclaim_args *ap));
204static int null_setattr __P((struct vop_setattr_args *ap));
205static int null_strategy __P((struct vop_strategy_args *ap));
206static int null_unlock __P((struct vop_unlock_args *ap));
207
208/*
209 * This is the 10-Apr-92 bypass routine.
210 * This version has been optimized for speed, throwing away some
211 * safety checks. It should still always work, but it's not as
212 * robust to programmer errors.
213 * Define SAFETY to include some error checking code.
214 *
215 * In general, we map all vnodes going down and unmap them on the way back.
216 * As an exception to this, vnodes can be marked "unmapped" by setting
217 * the Nth bit in operation's vdesc_flags.
218 *
219 * Also, some BSD vnode operations have the side effect of vrele'ing
220 * their arguments. With stacking, the reference counts are held
221 * by the upper node, not the lower one, so we must handle these
222 * side-effects here. This is not of concern in Sun-derived systems
223 * since there are no such side-effects.
224 *
225 * This makes the following assumptions:
226 * - only one returned vpp
227 * - no INOUT vpp's (Sun's vop_open has one of these)
228 * - the vnode operation vector of the first vnode should be used
229 * to determine what implementation of the op should be invoked
230 * - all mapped vnodes are of our vnode-type (NEEDSWORK:
231 * problems on rmdir'ing mount points and renaming?)
232 */
233int
234null_bypass(ap)
235 struct vop_generic_args /* {
236 struct vnodeop_desc *a_desc;
237 <other random data follows, presumably>
238 } */ *ap;
239{
240 register struct vnode **this_vp_p;
241 int error;
242 struct vnode *old_vps[VDESC_MAX_VPS];
243 struct vnode **vps_p[VDESC_MAX_VPS];
244 struct vnode ***vppp;
245 struct vnodeop_desc *descp = ap->a_desc;
246 int reles, i;
247
248 if (null_bug_bypass)
249 printf ("null_bypass: %s\n", descp->vdesc_name);
250
251#ifdef SAFETY
252 /*
253 * We require at least one vp.
254 */
255 if (descp->vdesc_vp_offsets == NULL ||
256 descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET)
257 panic ("null_bypass: no vp's in map.");
258#endif
259
260 /*
261 * Map the vnodes going in.
262 * Later, we'll invoke the operation based on
263 * the first mapped vnode's operation vector.
264 */
265 reles = descp->vdesc_flags;
266 for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
267 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
268 break; /* bail out at end of list */
269 vps_p[i] = this_vp_p =
270 VOPARG_OFFSETTO(struct vnode**,descp->vdesc_vp_offsets[i],ap);
271 /*
272 * We're not guaranteed that any but the first vnode
273 * are of our type. Check for and don't map any
274 * that aren't. (We must always map first vp or vclean fails.)
275 */
276 if (i && (*this_vp_p == NULL ||
277 (*this_vp_p)->v_op != null_vnodeop_p)) {
278 old_vps[i] = NULL;
279 } else {
280 old_vps[i] = *this_vp_p;
281 *(vps_p[i]) = NULLVPTOLOWERVP(*this_vp_p);
282 /*
283 * XXX - Several operations have the side effect
284 * of vrele'ing their vp's. We must account for
285 * that. (This should go away in the future.)
286 */
287 if (reles & 1)
288 VREF(*this_vp_p);
289 }
290
291 }
292
293 /*
294 * Call the operation on the lower layer
295 * with the modified argument structure.
296 */
297 error = VCALL(*(vps_p[0]), descp->vdesc_offset, ap);
298
299 /*
300 * Maintain the illusion of call-by-value
301 * by restoring vnodes in the argument structure
302 * to their original value.
303 */
304 reles = descp->vdesc_flags;
305 for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
306 if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
307 break; /* bail out at end of list */
308 if (old_vps[i]) {
309 *(vps_p[i]) = old_vps[i];
310 if (reles & 1)
311 vrele(*(vps_p[i]));
312 }
313 }
314
315 /*
316 * Map the possible out-going vpp
317 * (Assumes that the lower layer always returns
318 * a VREF'ed vpp unless it gets an error.)
319 */
320 if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET &&
321 !(descp->vdesc_flags & VDESC_NOMAP_VPP) &&
322 !error) {
323 /*
324 * XXX - even though some ops have vpp returned vp's,
325 * several ops actually vrele this before returning.
326 * We must avoid these ops.
327 * (This should go away when these ops are regularized.)
328 */
329 if (descp->vdesc_flags & VDESC_VPP_WILLRELE)
330 goto out;
331 vppp = VOPARG_OFFSETTO(struct vnode***,
332 descp->vdesc_vpp_offset,ap);
333 error = null_node_create(old_vps[0]->v_mount, **vppp, *vppp);
334 }
335
336 out:
337 return (error);
338}
339
340/*
341 * We have to carry on the locking protocol on the null layer vnodes
342 * as we progress through the tree. We also have to enforce read-only
343 * if this layer is mounted read-only.
344 */
345static int
346null_lookup(ap)
347 struct vop_lookup_args /* {
348 struct vnode * a_dvp;
349 struct vnode ** a_vpp;
350 struct componentname * a_cnp;
351 } */ *ap;
352{
353 struct componentname *cnp = ap->a_cnp;
354 struct proc *p = cnp->cn_proc;
355 int flags = cnp->cn_flags;
356 struct vop_lock_args lockargs;
357 struct vop_unlock_args unlockargs;
358 struct vnode *dvp, *vp;
359 int error;
360
361 if ((flags & ISLASTCN) && (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) &&
362 (cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
363 return (EROFS);
|
364 error = null_bypass(ap);
| 364 error = null_bypass((struct vop_generic_args *)ap);
|
365 if (error == EJUSTRETURN && (flags & ISLASTCN) &&
366 (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) &&
367 (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME))
368 error = EROFS;
369 /*
370 * We must do the same locking and unlocking at this layer as
371 * is done in the layers below us. We could figure this out
372 * based on the error return and the LASTCN, LOCKPARENT, and
373 * LOCKLEAF flags. However, it is more expidient to just find
374 * out the state of the lower level vnodes and set ours to the
375 * same state.
376 */
377 dvp = ap->a_dvp;
378 vp = *ap->a_vpp;
379 if (dvp == vp)
380 return (error);
381 if (!VOP_ISLOCKED(dvp)) {
382 unlockargs.a_vp = dvp;
383 unlockargs.a_flags = 0;
384 unlockargs.a_p = p;
385 vop_nounlock(&unlockargs);
386 }
387 if (vp != NULL && VOP_ISLOCKED(vp)) {
388 lockargs.a_vp = vp;
389 lockargs.a_flags = LK_SHARED;
390 lockargs.a_p = p;
391 vop_nolock(&lockargs);
392 }
393 return (error);
394}
395
396/*
397 * Setattr call. Disallow write attempts if the layer is mounted read-only.
398 */
399int
400null_setattr(ap)
401 struct vop_setattr_args /* {
402 struct vnodeop_desc *a_desc;
403 struct vnode *a_vp;
404 struct vattr *a_vap;
405 struct ucred *a_cred;
406 struct proc *a_p;
407 } */ *ap;
408{
409 struct vnode *vp = ap->a_vp;
410 struct vattr *vap = ap->a_vap;
411
412 if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
413 vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
414 vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) &&
415 (vp->v_mount->mnt_flag & MNT_RDONLY))
416 return (EROFS);
417 if (vap->va_size != VNOVAL) {
418 switch (vp->v_type) {
419 case VDIR:
420 return (EISDIR);
421 case VCHR:
422 case VBLK:
423 case VSOCK:
424 case VFIFO:
425 return (0);
426 case VREG:
427 case VLNK:
428 default:
429 /*
430 * Disallow write attempts if the filesystem is
431 * mounted read-only.
432 */
433 if (vp->v_mount->mnt_flag & MNT_RDONLY)
434 return (EROFS);
435 }
436 }
| 365 if (error == EJUSTRETURN && (flags & ISLASTCN) &&
366 (ap->a_dvp->v_mount->mnt_flag & MNT_RDONLY) &&
367 (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME))
368 error = EROFS;
369 /*
370 * We must do the same locking and unlocking at this layer as
371 * is done in the layers below us. We could figure this out
372 * based on the error return and the LASTCN, LOCKPARENT, and
373 * LOCKLEAF flags. However, it is more expidient to just find
374 * out the state of the lower level vnodes and set ours to the
375 * same state.
376 */
377 dvp = ap->a_dvp;
378 vp = *ap->a_vpp;
379 if (dvp == vp)
380 return (error);
381 if (!VOP_ISLOCKED(dvp)) {
382 unlockargs.a_vp = dvp;
383 unlockargs.a_flags = 0;
384 unlockargs.a_p = p;
385 vop_nounlock(&unlockargs);
386 }
387 if (vp != NULL && VOP_ISLOCKED(vp)) {
388 lockargs.a_vp = vp;
389 lockargs.a_flags = LK_SHARED;
390 lockargs.a_p = p;
391 vop_nolock(&lockargs);
392 }
393 return (error);
394}
395
396/*
397 * Setattr call. Disallow write attempts if the layer is mounted read-only.
398 */
399int
400null_setattr(ap)
401 struct vop_setattr_args /* {
402 struct vnodeop_desc *a_desc;
403 struct vnode *a_vp;
404 struct vattr *a_vap;
405 struct ucred *a_cred;
406 struct proc *a_p;
407 } */ *ap;
408{
409 struct vnode *vp = ap->a_vp;
410 struct vattr *vap = ap->a_vap;
411
412 if ((vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
413 vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
414 vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL) &&
415 (vp->v_mount->mnt_flag & MNT_RDONLY))
416 return (EROFS);
417 if (vap->va_size != VNOVAL) {
418 switch (vp->v_type) {
419 case VDIR:
420 return (EISDIR);
421 case VCHR:
422 case VBLK:
423 case VSOCK:
424 case VFIFO:
425 return (0);
426 case VREG:
427 case VLNK:
428 default:
429 /*
430 * Disallow write attempts if the filesystem is
431 * mounted read-only.
432 */
433 if (vp->v_mount->mnt_flag & MNT_RDONLY)
434 return (EROFS);
435 }
436 }
|
437 return (null_bypass(ap));
| 437 return (null_bypass((struct vop_generic_args *)ap));
|
438}
439
440/*
441 * We handle getattr only to change the fsid.
442 */
443static int
444null_getattr(ap)
445 struct vop_getattr_args /* {
446 struct vnode *a_vp;
447 struct vattr *a_vap;
448 struct ucred *a_cred;
449 struct proc *a_p;
450 } */ *ap;
451{
452 int error;
453
| 438}
439
440/*
441 * We handle getattr only to change the fsid.
442 */
443static int
444null_getattr(ap)
445 struct vop_getattr_args /* {
446 struct vnode *a_vp;
447 struct vattr *a_vap;
448 struct ucred *a_cred;
449 struct proc *a_p;
450 } */ *ap;
451{
452 int error;
453
|
454 if (error = null_bypass(ap))
| 454 if (error = null_bypass((struct vop_generic_args *)ap))
|
455 return (error);
456 /* Requires that arguments be restored. */
457 ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
458 return (0);
459}
460
461static int
462null_access(ap)
463 struct vop_access_args /* {
464 struct vnode *a_vp;
465 int a_mode;
466 struct ucred *a_cred;
467 struct proc *a_p;
468 } */ *ap;
469{
470 struct vnode *vp = ap->a_vp;
471 mode_t mode = ap->a_mode;
472
473 /*
474 * Disallow write attempts on read-only layers;
475 * unless the file is a socket, fifo, or a block or
476 * character device resident on the file system.
477 */
478 if (mode & VWRITE) {
479 switch (vp->v_type) {
480 case VDIR:
481 case VLNK:
482 case VREG:
483 if (vp->v_mount->mnt_flag & MNT_RDONLY)
484 return (EROFS);
485 break;
486 }
487 }
| 455 return (error);
456 /* Requires that arguments be restored. */
457 ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
458 return (0);
459}
460
461static int
462null_access(ap)
463 struct vop_access_args /* {
464 struct vnode *a_vp;
465 int a_mode;
466 struct ucred *a_cred;
467 struct proc *a_p;
468 } */ *ap;
469{
470 struct vnode *vp = ap->a_vp;
471 mode_t mode = ap->a_mode;
472
473 /*
474 * Disallow write attempts on read-only layers;
475 * unless the file is a socket, fifo, or a block or
476 * character device resident on the file system.
477 */
478 if (mode & VWRITE) {
479 switch (vp->v_type) {
480 case VDIR:
481 case VLNK:
482 case VREG:
483 if (vp->v_mount->mnt_flag & MNT_RDONLY)
484 return (EROFS);
485 break;
486 }
487 }
|
488 return (null_bypass(ap));
| 488 return (null_bypass((struct vop_generic_args *)ap));
|
489}
490
491/*
492 * We need to process our own vnode lock and then clear the
493 * interlock flag as it applies only to our vnode, not the
494 * vnodes below us on the stack.
495 */
496static int
497null_lock(ap)
498 struct vop_lock_args /* {
499 struct vnode *a_vp;
500 int a_flags;
501 struct proc *a_p;
502 } */ *ap;
503{
504
505 vop_nolock(ap);
506 if ((ap->a_flags & LK_TYPE_MASK) == LK_DRAIN)
507 return (0);
508 ap->a_flags &= ~LK_INTERLOCK;
| 489}
490
491/*
492 * We need to process our own vnode lock and then clear the
493 * interlock flag as it applies only to our vnode, not the
494 * vnodes below us on the stack.
495 */
496static int
497null_lock(ap)
498 struct vop_lock_args /* {
499 struct vnode *a_vp;
500 int a_flags;
501 struct proc *a_p;
502 } */ *ap;
503{
504
505 vop_nolock(ap);
506 if ((ap->a_flags & LK_TYPE_MASK) == LK_DRAIN)
507 return (0);
508 ap->a_flags &= ~LK_INTERLOCK;
|
509 return (null_bypass(ap));
| 509 return (null_bypass((struct vop_generic_args *)ap));
|
510}
511
512/*
513 * We need to process our own vnode unlock and then clear the
514 * interlock flag as it applies only to our vnode, not the
515 * vnodes below us on the stack.
516 */
517static int
518null_unlock(ap)
519 struct vop_unlock_args /* {
520 struct vnode *a_vp;
521 int a_flags;
522 struct proc *a_p;
523 } */ *ap;
524{
525 struct vnode *vp = ap->a_vp;
526
527 vop_nounlock(ap);
528 ap->a_flags &= ~LK_INTERLOCK;
| 510}
511
512/*
513 * We need to process our own vnode unlock and then clear the
514 * interlock flag as it applies only to our vnode, not the
515 * vnodes below us on the stack.
516 */
517static int
518null_unlock(ap)
519 struct vop_unlock_args /* {
520 struct vnode *a_vp;
521 int a_flags;
522 struct proc *a_p;
523 } */ *ap;
524{
525 struct vnode *vp = ap->a_vp;
526
527 vop_nounlock(ap);
528 ap->a_flags &= ~LK_INTERLOCK;
|
529 return (null_bypass(ap));
| 529 return (null_bypass((struct vop_generic_args *)ap));
|
530}
531
532static int
533null_inactive(ap)
534 struct vop_inactive_args /* {
535 struct vnode *a_vp;
536 struct proc *a_p;
537 } */ *ap;
538{
539 /*
540 * Do nothing (and _don't_ bypass).
541 * Wait to vrele lowervp until reclaim,
542 * so that until then our null_node is in the
543 * cache and reusable.
544 *
545 * NEEDSWORK: Someday, consider inactive'ing
546 * the lowervp and then trying to reactivate it
547 * with capabilities (v_id)
548 * like they do in the name lookup cache code.
549 * That's too much work for now.
550 */
551 VOP_UNLOCK(ap->a_vp, 0, ap->a_p);
552 return (0);
553}
554
555static int
556null_reclaim(ap)
557 struct vop_reclaim_args /* {
558 struct vnode *a_vp;
559 struct proc *a_p;
560 } */ *ap;
561{
562 struct vnode *vp = ap->a_vp;
563 struct null_node *xp = VTONULL(vp);
564 struct vnode *lowervp = xp->null_lowervp;
565
566 /*
567 * Note: in vop_reclaim, vp->v_op == dead_vnodeop_p,
568 * so we can't call VOPs on ourself.
569 */
570 /* After this assignment, this node will not be re-used. */
571 xp->null_lowervp = NULL;
572 LIST_REMOVE(xp, null_hash);
573 FREE(vp->v_data, M_TEMP);
574 vp->v_data = NULL;
575 vrele (lowervp);
576 return (0);
577}
578
579static int
580null_print(ap)
581 struct vop_print_args /* {
582 struct vnode *a_vp;
583 } */ *ap;
584{
585 register struct vnode *vp = ap->a_vp;
586 printf ("\ttag VT_NULLFS, vp=%p, lowervp=%p\n", vp, NULLVPTOLOWERVP(vp));
587 return (0);
588}
589
590/*
591 * XXX - vop_strategy must be hand coded because it has no
592 * vnode in its arguments.
593 * This goes away with a merged VM/buffer cache.
594 */
595static int
596null_strategy(ap)
597 struct vop_strategy_args /* {
598 struct buf *a_bp;
599 } */ *ap;
600{
601 struct buf *bp = ap->a_bp;
602 int error;
603 struct vnode *savedvp;
604
605 savedvp = bp->b_vp;
606 bp->b_vp = NULLVPTOLOWERVP(bp->b_vp);
607
608 error = VOP_STRATEGY(bp);
609
610 bp->b_vp = savedvp;
611
612 return (error);
613}
614
615/*
616 * XXX - like vop_strategy, vop_bwrite must be hand coded because it has no
617 * vnode in its arguments.
618 * This goes away with a merged VM/buffer cache.
619 */
620static int
621null_bwrite(ap)
622 struct vop_bwrite_args /* {
623 struct buf *a_bp;
624 } */ *ap;
625{
626 struct buf *bp = ap->a_bp;
627 int error;
628 struct vnode *savedvp;
629
630 savedvp = bp->b_vp;
631 bp->b_vp = NULLVPTOLOWERVP(bp->b_vp);
632
633 error = VOP_BWRITE(bp);
634
635 bp->b_vp = savedvp;
636
637 return (error);
638}
639
640/*
641 * Global vfs data structures
642 */
643vop_t **null_vnodeop_p;
644static struct vnodeopv_entry_desc null_vnodeop_entries[] = {
645 { &vop_default_desc, (vop_t *)null_bypass },
646
647 { &vop_lookup_desc, (vop_t *)null_lookup },
648 { &vop_setattr_desc, (vop_t *)null_setattr },
649 { &vop_getattr_desc, (vop_t *)null_getattr },
650 { &vop_access_desc, (vop_t *)null_access },
651 { &vop_lock_desc, (vop_t *)null_lock },
652 { &vop_unlock_desc, (vop_t *)null_unlock },
653 { &vop_inactive_desc, (vop_t *)null_inactive },
654 { &vop_reclaim_desc, (vop_t *)null_reclaim },
655 { &vop_print_desc, (vop_t *)null_print },
656
657 { &vop_strategy_desc, (vop_t *)null_strategy },
658 { &vop_bwrite_desc, (vop_t *)null_bwrite },
659
660 { NULL, NULL }
661};
662static struct vnodeopv_desc null_vnodeop_opv_desc =
663 { &null_vnodeop_p, null_vnodeop_entries };
664
665VNODEOP_SET(null_vnodeop_opv_desc);
| 530}
531
532static int
533null_inactive(ap)
534 struct vop_inactive_args /* {
535 struct vnode *a_vp;
536 struct proc *a_p;
537 } */ *ap;
538{
539 /*
540 * Do nothing (and _don't_ bypass).
541 * Wait to vrele lowervp until reclaim,
542 * so that until then our null_node is in the
543 * cache and reusable.
544 *
545 * NEEDSWORK: Someday, consider inactive'ing
546 * the lowervp and then trying to reactivate it
547 * with capabilities (v_id)
548 * like they do in the name lookup cache code.
549 * That's too much work for now.
550 */
551 VOP_UNLOCK(ap->a_vp, 0, ap->a_p);
552 return (0);
553}
554
555static int
556null_reclaim(ap)
557 struct vop_reclaim_args /* {
558 struct vnode *a_vp;
559 struct proc *a_p;
560 } */ *ap;
561{
562 struct vnode *vp = ap->a_vp;
563 struct null_node *xp = VTONULL(vp);
564 struct vnode *lowervp = xp->null_lowervp;
565
566 /*
567 * Note: in vop_reclaim, vp->v_op == dead_vnodeop_p,
568 * so we can't call VOPs on ourself.
569 */
570 /* After this assignment, this node will not be re-used. */
571 xp->null_lowervp = NULL;
572 LIST_REMOVE(xp, null_hash);
573 FREE(vp->v_data, M_TEMP);
574 vp->v_data = NULL;
575 vrele (lowervp);
576 return (0);
577}
578
579static int
580null_print(ap)
581 struct vop_print_args /* {
582 struct vnode *a_vp;
583 } */ *ap;
584{
585 register struct vnode *vp = ap->a_vp;
586 printf ("\ttag VT_NULLFS, vp=%p, lowervp=%p\n", vp, NULLVPTOLOWERVP(vp));
587 return (0);
588}
589
590/*
591 * XXX - vop_strategy must be hand coded because it has no
592 * vnode in its arguments.
593 * This goes away with a merged VM/buffer cache.
594 */
595static int
596null_strategy(ap)
597 struct vop_strategy_args /* {
598 struct buf *a_bp;
599 } */ *ap;
600{
601 struct buf *bp = ap->a_bp;
602 int error;
603 struct vnode *savedvp;
604
605 savedvp = bp->b_vp;
606 bp->b_vp = NULLVPTOLOWERVP(bp->b_vp);
607
608 error = VOP_STRATEGY(bp);
609
610 bp->b_vp = savedvp;
611
612 return (error);
613}
614
615/*
616 * XXX - like vop_strategy, vop_bwrite must be hand coded because it has no
617 * vnode in its arguments.
618 * This goes away with a merged VM/buffer cache.
619 */
620static int
621null_bwrite(ap)
622 struct vop_bwrite_args /* {
623 struct buf *a_bp;
624 } */ *ap;
625{
626 struct buf *bp = ap->a_bp;
627 int error;
628 struct vnode *savedvp;
629
630 savedvp = bp->b_vp;
631 bp->b_vp = NULLVPTOLOWERVP(bp->b_vp);
632
633 error = VOP_BWRITE(bp);
634
635 bp->b_vp = savedvp;
636
637 return (error);
638}
639
640/*
641 * Global vfs data structures
642 */
643vop_t **null_vnodeop_p;
644static struct vnodeopv_entry_desc null_vnodeop_entries[] = {
645 { &vop_default_desc, (vop_t *)null_bypass },
646
647 { &vop_lookup_desc, (vop_t *)null_lookup },
648 { &vop_setattr_desc, (vop_t *)null_setattr },
649 { &vop_getattr_desc, (vop_t *)null_getattr },
650 { &vop_access_desc, (vop_t *)null_access },
651 { &vop_lock_desc, (vop_t *)null_lock },
652 { &vop_unlock_desc, (vop_t *)null_unlock },
653 { &vop_inactive_desc, (vop_t *)null_inactive },
654 { &vop_reclaim_desc, (vop_t *)null_reclaim },
655 { &vop_print_desc, (vop_t *)null_print },
656
657 { &vop_strategy_desc, (vop_t *)null_strategy },
658 { &vop_bwrite_desc, (vop_t *)null_bwrite },
659
660 { NULL, NULL }
661};
662static struct vnodeopv_desc null_vnodeop_opv_desc =
663 { &null_vnodeop_p, null_vnodeop_entries };
664
665VNODEOP_SET(null_vnodeop_opv_desc);
|