xref: /freebsd/sys/kern/vfs_init.c (revision 0de89efe5c443f213c7ea28773ef2dc6cf3af2ed)
1 /*
2  * Copyright (c) 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed
6  * to Berkeley by John Heidemann of the UCLA Ficus project.
7  *
8  * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)vfs_init.c	8.3 (Berkeley) 1/4/94
39  * $Id: vfs_init.c,v 1.27 1997/09/10 20:11:01 phk Exp $
40  */
41 
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/kernel.h>
46 #include <sys/mount.h>
47 #include <sys/vnode.h>
48 #include <sys/malloc.h>
49 #include <vm/vm_zone.h>
50 
51 static void	vfs_op_init __P((void));
52 
53 static void vfsinit __P((void *));
54 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vfsinit, NULL)
55 
56 /*
57  * Sigh, such primitive tools are these...
58  */
59 #if 0
60 #define DODEBUG(A) A
61 #else
62 #define DODEBUG(A)
63 #endif
64 
65 struct vfsconf void_vfsconf;
66 
67 extern struct linker_set vfs_opv_descs_;
68 #define vfs_opv_descs ((struct vnodeopv_desc **)vfs_opv_descs_.ls_items)
69 
70 extern struct linker_set vfs_set;
71 
72 extern struct vnodeop_desc *vfs_op_descs[];
73 				/* and the operations they perform */
74 
75 /*
76  * Zone for namei
77  */
78 struct vm_zone *namei_zone;
79 
80 /*
81  * A miscellaneous routine.
82  * A generic "default" routine that just returns an error.
83  */
84 int
85 vn_default_error()
86 {
87 
88 	return (EOPNOTSUPP);
89 }
90 
91 /*
92  * vfs_init.c
93  *
94  * Allocate and fill in operations vectors.
95  *
96  * An undocumented feature of this approach to defining operations is that
97  * there can be multiple entries in vfs_opv_descs for the same operations
98  * vector. This allows third parties to extend the set of operations
99  * supported by another layer in a binary compatibile way. For example,
100  * assume that NFS needed to be modified to support Ficus. NFS has an entry
101  * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by
102  * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions)
103  * listing those new operations Ficus adds to NFS, all without modifying the
104  * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but
105  * that is a(whole)nother story.) This is a feature.
106  *
107  * Without an explicit reserve area, however, you must replace vnode_if.c
108  * and vnode_if.h when you do this, or you will be derefrencing of the
109  * end of vfs_op_descs[].  This is a flaw in the use of a structure
110  * pointer array rather than an agregate to define vfs_op_descs.  So
111  * it's not a very dynamic "feature".
112  */
113 void
114 vfs_opv_init(struct vnodeopv_desc **them)
115 {
116 	int i, j, k;
117 	vop_t ***opv_desc_vector_p;
118 	vop_t **opv_desc_vector;
119 	struct vnodeopv_entry_desc *opve_descp;
120 
121 	/*
122 	 * Allocate the dynamic vectors and fill them in.
123 	 */
124 	for (i=0; them[i]; i++) {
125 		opv_desc_vector_p = them[i]->opv_desc_vector_p;
126 		/*
127 		 * Allocate and init the vector, if it needs it.
128 		 * Also handle backwards compatibility.
129 		 */
130 		if (*opv_desc_vector_p == NULL) {
131 			/* XXX - shouldn't be M_VNODE */
132 			MALLOC(*opv_desc_vector_p, vop_t **,
133 			       vfs_opv_numops * sizeof(vop_t *), M_VNODE,
134 			       M_WAITOK);
135 			bzero(*opv_desc_vector_p,
136 			      vfs_opv_numops * sizeof(vop_t *));
137 			DODEBUG(printf("vector at %x allocated\n",
138 			    opv_desc_vector_p));
139 		}
140 		opv_desc_vector = *opv_desc_vector_p;
141 		for (j=0; them[i]->opv_desc_ops[j].opve_op; j++) {
142 			opve_descp = &(them[i]->opv_desc_ops[j]);
143 
144 			/*
145 			 * Sanity check:  is this operation listed
146 			 * in the list of operations?  We check this
147 			 * by seeing if its offest is zero.  Since
148 			 * the default routine should always be listed
149 			 * first, it should be the only one with a zero
150 			 * offset.  Any other operation with a zero
151 			 * offset is probably not listed in
152 			 * vfs_op_descs, and so is probably an error.
153 			 *
154 			 * A panic here means the layer programmer
155 			 * has committed the all-too common bug
156 			 * of adding a new operation to the layer's
157 			 * list of vnode operations but
158 			 * not adding the operation to the system-wide
159 			 * list of supported operations.
160 			 */
161 			if (opve_descp->opve_op->vdesc_offset == 0 &&
162 				    opve_descp->opve_op->vdesc_offset !=
163 				    	VOFFSET(vop_default)) {
164 				printf("operation %s not listed in %s.\n",
165 				    opve_descp->opve_op->vdesc_name,
166 				    "vfs_op_descs");
167 				panic ("vfs_opv_init: bad operation");
168 			}
169 			/*
170 			 * Fill in this entry.
171 			 */
172 			opv_desc_vector[opve_descp->opve_op->vdesc_offset] =
173 					opve_descp->opve_impl;
174 		}
175 	}
176 	/*
177 	 * Finally, go back and replace unfilled routines
178 	 * with their default.  (Sigh, an O(n^3) algorithm.  I
179 	 * could make it better, but that'd be work, and n is small.)
180 	 */
181 	for (i = 0; them[i]; i++) {
182 		opv_desc_vector = *(them[i]->opv_desc_vector_p);
183 		/*
184 		 * Force every operations vector to have a default routine.
185 		 */
186 		if (opv_desc_vector[VOFFSET(vop_default)]==NULL) {
187 			panic("vfs_opv_init: operation vector without default routine.");
188 		}
189 		for (k = 0; k<vfs_opv_numops; k++)
190 			if (opv_desc_vector[k] == NULL)
191 				opv_desc_vector[k] =
192 					opv_desc_vector[VOFFSET(vop_default)];
193 	}
194 }
195 
196 /*
197  * Initialize known vnode operations vectors.
198  */
199 static void
200 vfs_op_init()
201 {
202 	int i;
203 
204 	DODEBUG(printf("Vnode_interface_init.\n"));
205 	DODEBUG(printf ("vfs_opv_numops=%d\n", vfs_opv_numops));
206 	/*
207 	 * Set all vnode vectors to a well known value.
208 	 */
209 	for (i = 0; vfs_opv_descs[i]; i++)
210 		*(vfs_opv_descs[i]->opv_desc_vector_p) = NULL;
211 	/*
212 	 * assign each op to its offset
213 	 *
214 	 * XXX This should not be needed, but is because the per
215 	 * XXX FS ops tables are not sorted according to the
216 	 * XXX vnodeop_desc's offset in vfs_op_descs.  This
217 	 * XXX is the same reason we have to take the hit for
218 	 * XXX the static inline function calls instead of using
219 	 * XXX simple macro references.
220 	 */
221 	for (i = 0; i < vfs_opv_numops; i++)
222 		vfs_op_descs[i]->vdesc_offset = i;
223 }
224 
225 /*
226  * Routines having to do with the management of the vnode table.
227  */
228 extern struct vnodeops dead_vnodeops;
229 extern struct vnodeops spec_vnodeops;
230 struct vattr va_null;
231 
232 /*
233  * Initialize the vnode structures and initialize each file system type.
234  */
235 /* ARGSUSED*/
236 static void
237 vfsinit(dummy)
238 	void *dummy;
239 {
240 	struct vfsconf **vfc;
241 	int maxtypenum;
242 
243 	namei_zone = zinit("NAMEI", MAXPATHLEN, 0, 0, 2);
244 
245 	/*
246 	 * Initialize the vnode table
247 	 */
248 	vntblinit();
249 	/*
250 	 * Initialize the vnode name cache
251 	 */
252 	nchinit();
253 	/*
254 	 * Build vnode operation vectors.
255 	 */
256 	vfs_op_init();
257 	vfs_opv_init(vfs_opv_descs);   /* finish the job */
258 	/*
259 	 * Initialize each file system type.
260 	 */
261 	vattr_null(&va_null);
262 	maxtypenum = 0;
263 	vfc = (struct vfsconf **)vfs_set.ls_items;
264 	vfsconf = *vfc;		/* simulate Lite2 vfsconf array */
265 	while (*vfc) {
266 		struct vfsconf *vfsp = *vfc;
267 
268 		vfc++;
269 		vfsp->vfc_next = *vfc;
270 		if (maxtypenum <= vfsp->vfc_typenum)
271 			maxtypenum = vfsp->vfc_typenum + 1;
272 		(*vfsp->vfc_vfsops->vfs_init)(vfsp);
273 	}
274 	/* next vfc_typenum to be used */
275 	maxvfsconf = maxtypenum;
276 }
277 
278 /*
279  * kernel related system variables.
280  */
281 
282 /*
283  * This goop is here to support a loadable NFS module... grumble...
284  */
285 int (*lease_check_hook) __P((struct vop_lease_args *))
286      = 0;
287 void (*lease_updatetime) __P((int))
288      = 0;
289 
290 int
291 lease_check(ap)
292 	struct vop_lease_args /* {
293 		struct vnode *a_vp;
294 		struct proc *a_p;
295 		struct ucred *a_cred;
296 		int a_flag;
297 	} */ *ap;
298 {
299     if (lease_check_hook)
300 	return (*lease_check_hook)(ap);
301     else
302 	return 0;
303 }
304