FreeBSD/Linux Kernel Cross Reference
sys/kern/vfs_init.c
1 /* $NetBSD: vfs_init.c,v 1.32 2006/11/01 10:17:59 yamt Exp $ */
2
3 /*-
4 * Copyright (c) 1998, 2000 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
9 * NASA Ames Research Center.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the NetBSD
22 * Foundation, Inc. and its contributors.
23 * 4. Neither the name of The NetBSD Foundation nor the names of its
24 * contributors may be used to endorse or promote products derived
25 * from this software without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37 * POSSIBILITY OF SUCH DAMAGE.
38 */
39
40 /*
41 * Copyright (c) 1989, 1993
42 * The Regents of the University of California. All rights reserved.
43 *
44 * This code is derived from software contributed
45 * to Berkeley by John Heidemann of the UCLA Ficus project.
46 *
47 * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
48 *
49 * Redistribution and use in source and binary forms, with or without
50 * modification, are permitted provided that the following conditions
51 * are met:
52 * 1. Redistributions of source code must retain the above copyright
53 * notice, this list of conditions and the following disclaimer.
54 * 2. Redistributions in binary form must reproduce the above copyright
55 * notice, this list of conditions and the following disclaimer in the
56 * documentation and/or other materials provided with the distribution.
57 * 3. Neither the name of the University nor the names of its contributors
58 * may be used to endorse or promote products derived from this software
59 * without specific prior written permission.
60 *
61 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
62 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
63 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
64 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
65 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
66 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
67 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
68 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
69 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
70 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
71 * SUCH DAMAGE.
72 *
73 * @(#)vfs_init.c 8.5 (Berkeley) 5/11/95
74 */
75
76 #include <sys/cdefs.h>
77 __KERNEL_RCSID(0, "$NetBSD: vfs_init.c,v 1.32 2006/11/01 10:17:59 yamt Exp $");
78
79 #include <sys/param.h>
80 #include <sys/mount.h>
81 #include <sys/time.h>
82 #include <sys/vnode.h>
83 #include <sys/stat.h>
84 #include <sys/namei.h>
85 #include <sys/ucred.h>
86 #include <sys/buf.h>
87 #include <sys/errno.h>
88 #include <sys/malloc.h>
89 #include <sys/systm.h>
90
91 /*
92 * Sigh, such primitive tools are these...
93 */
94 #if 0
95 #define DODEBUG(A) A
96 #else
97 #define DODEBUG(A)
98 #endif
99
100 /*
101 * The global list of vnode operations.
102 */
103 extern const struct vnodeop_desc * const vfs_op_descs[];
104
105 /*
106 * These vnodeopv_descs are listed here because they are not
107 * associated with any particular file system, and thus cannot
108 * be initialized by vfs_attach().
109 */
110 extern const struct vnodeopv_desc dead_vnodeop_opv_desc;
111 extern const struct vnodeopv_desc fifo_vnodeop_opv_desc;
112 extern const struct vnodeopv_desc spec_vnodeop_opv_desc;
113 extern const struct vnodeopv_desc sync_vnodeop_opv_desc;
114
115 const struct vnodeopv_desc * const vfs_special_vnodeopv_descs[] = {
116 &dead_vnodeop_opv_desc,
117 &fifo_vnodeop_opv_desc,
118 &spec_vnodeop_opv_desc,
119 &sync_vnodeop_opv_desc,
120 NULL,
121 };
122
123 /*
124 * This code doesn't work if the defn is **vnodop_defns with cc.
125 * The problem is because of the compiler sometimes putting in an
126 * extra level of indirection for arrays. It's an interesting
127 * "feature" of C.
128 */
129 typedef int (*PFI)(void *);
130
131 /*
132 * A miscellaneous routine.
133 * A generic "default" routine that just returns an error.
134 */
135 /*ARGSUSED*/
136 int
137 vn_default_error(void *v)
138 {
139
140 return (EOPNOTSUPP);
141 }
142
143 /*
144 * vfs_init.c
145 *
146 * Allocate and fill in operations vectors.
147 *
148 * An undocumented feature of this approach to defining operations is that
149 * there can be multiple entries in vfs_opv_descs for the same operations
150 * vector. This allows third parties to extend the set of operations
151 * supported by another layer in a binary compatibile way. For example,
152 * assume that NFS needed to be modified to support Ficus. NFS has an entry
153 * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by
154 * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions)
155 * listing those new operations Ficus adds to NFS, all without modifying the
156 * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but
157 * that is a(whole)nother story.) This is a feature.
158 */
159
160 /*
161 * Init the vector, if it needs it.
162 * Also handle backwards compatibility.
163 */
164 static void
165 vfs_opv_init_explicit(const struct vnodeopv_desc *vfs_opv_desc)
166 {
167 int (**opv_desc_vector)(void *);
168 const struct vnodeopv_entry_desc *opve_descp;
169
170 opv_desc_vector = *(vfs_opv_desc->opv_desc_vector_p);
171
172 for (opve_descp = vfs_opv_desc->opv_desc_ops;
173 opve_descp->opve_op;
174 opve_descp++) {
175 /*
176 * Sanity check: is this operation listed
177 * in the list of operations? We check this
178 * by seeing if its offset is zero. Since
179 * the default routine should always be listed
180 * first, it should be the only one with a zero
181 * offset. Any other operation with a zero
182 * offset is probably not listed in
183 * vfs_op_descs, and so is probably an error.
184 *
185 * A panic here means the layer programmer
186 * has committed the all-too common bug
187 * of adding a new operation to the layer's
188 * list of vnode operations but
189 * not adding the operation to the system-wide
190 * list of supported operations.
191 */
192 if (opve_descp->opve_op->vdesc_offset == 0 &&
193 opve_descp->opve_op->vdesc_offset != VOFFSET(vop_default)) {
194 printf("operation %s not listed in %s.\n",
195 opve_descp->opve_op->vdesc_name, "vfs_op_descs");
196 panic ("vfs_opv_init: bad operation");
197 }
198
199 /*
200 * Fill in this entry.
201 */
202 opv_desc_vector[opve_descp->opve_op->vdesc_offset] =
203 opve_descp->opve_impl;
204 }
205 }
206
207 static void
208 vfs_opv_init_default(const struct vnodeopv_desc *vfs_opv_desc)
209 {
210 int j;
211 int (**opv_desc_vector)(void *);
212
213 opv_desc_vector = *(vfs_opv_desc->opv_desc_vector_p);
214
215 /*
216 * Force every operations vector to have a default routine.
217 */
218 if (opv_desc_vector[VOFFSET(vop_default)] == NULL)
219 panic("vfs_opv_init: operation vector without default routine.");
220
221 for (j = 0; j < VNODE_OPS_COUNT; j++)
222 if (opv_desc_vector[j] == NULL)
223 opv_desc_vector[j] =
224 opv_desc_vector[VOFFSET(vop_default)];
225 }
226
227 void
228 vfs_opv_init(const struct vnodeopv_desc * const *vopvdpp)
229 {
230 int (**opv_desc_vector)(void *);
231 int i;
232
233 /*
234 * Allocate the vectors.
235 */
236 for (i = 0; vopvdpp[i] != NULL; i++) {
237 /* XXX - shouldn't be M_VNODE */
238 opv_desc_vector =
239 malloc(VNODE_OPS_COUNT * sizeof(PFI), M_VNODE, M_WAITOK);
240 memset(opv_desc_vector, 0, VNODE_OPS_COUNT * sizeof(PFI));
241 *(vopvdpp[i]->opv_desc_vector_p) = opv_desc_vector;
242 DODEBUG(printf("vector at %p allocated\n",
243 opv_desc_vector_p));
244 }
245
246 /*
247 * ...and fill them in.
248 */
249 for (i = 0; vopvdpp[i] != NULL; i++)
250 vfs_opv_init_explicit(vopvdpp[i]);
251
252 /*
253 * Finally, go back and replace unfilled routines
254 * with their default.
255 */
256 for (i = 0; vopvdpp[i] != NULL; i++)
257 vfs_opv_init_default(vopvdpp[i]);
258 }
259
260 void
261 vfs_opv_free(const struct vnodeopv_desc * const *vopvdpp)
262 {
263 int i;
264
265 /*
266 * Free the vectors allocated in vfs_opv_init().
267 */
268 for (i = 0; vopvdpp[i] != NULL; i++) {
269 /* XXX - shouldn't be M_VNODE */
270 free(*(vopvdpp[i]->opv_desc_vector_p), M_VNODE);
271 *(vopvdpp[i]->opv_desc_vector_p) = NULL;
272 }
273 }
274
275 #ifdef DEBUG
276 static void
277 vfs_op_check(void)
278 {
279 int i;
280
281 DODEBUG(printf("Vnode_interface_init.\n"));
282
283 /*
284 * Check offset of each op.
285 */
286 for (i = 0; vfs_op_descs[i]; i++) {
287 if (vfs_op_descs[i]->vdesc_offset != i)
288 panic("vfs_op_check: vfs_op_desc[] offset mismatch");
289 }
290
291 if (i != VNODE_OPS_COUNT) {
292 panic("vfs_op_check: vnode ops count mismatch (%d != %d)",
293 i, VNODE_OPS_COUNT);
294 }
295
296 DODEBUG(printf ("vfs_opv_numops=%d\n", VNODE_OPS_COUNT));
297 }
298 #endif /* DEBUG */
299
300 /*
301 * Initialize the vnode structures and initialize each file system type.
302 */
303 void
304 vfsinit(void)
305 {
306 __link_set_decl(vfsops, struct vfsops);
307 struct vfsops * const *vfsp;
308
309 /*
310 * Initialize the namei pathname buffer pool and cache.
311 */
312 pool_init(&pnbuf_pool, MAXPATHLEN, 0, 0, 0, "pnbufpl",
313 &pool_allocator_nointr);
314 pool_cache_init(&pnbuf_cache, &pnbuf_pool, NULL, NULL, NULL);
315
316 /*
317 * Initialize the vnode table
318 */
319 vntblinit();
320
321 /*
322 * Initialize the vnode name cache
323 */
324 nchinit();
325
326 #ifdef DEBUG
327 /*
328 * Check the list of vnode operations.
329 */
330 vfs_op_check();
331 #endif
332
333 /*
334 * Initialize the special vnode operations.
335 */
336 vfs_opv_init(vfs_special_vnodeopv_descs);
337
338 /*
339 * Establish each file system which was statically
340 * included in the kernel.
341 */
342 __link_set_foreach(vfsp, vfsops) {
343 if (vfs_attach(*vfsp)) {
344 printf("multiple `%s' file systems",
345 (*vfsp)->vfs_name);
346 panic("vfsinit");
347 }
348 }
349 }
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