vfs_init.c revision 30739
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 1.30 1997/10/16 10:47:57 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
51static void	vfs_op_init __P((void));
52
53static void vfsinit __P((void *));
54SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vfsinit, NULL)
55
56MALLOC_DEFINE(M_VNODE, "vnodes", "Dynamically allocated vnodes");
57
58/*
59 * Sigh, such primitive tools are these...
60 */
61#if 0
62#define DODEBUG(A) A
63#else
64#define DODEBUG(A)
65#endif
66
67struct vfsconf void_vfsconf;
68
69extern struct linker_set vfs_opv_descs_;
70#define vfs_opv_descs ((struct vnodeopv_desc **)vfs_opv_descs_.ls_items)
71
72extern struct linker_set vfs_set;
73
74extern struct vnodeop_desc *vfs_op_descs[];
75				/* and the operations they perform */
76
77/*
78 * Zone for namei
79 */
80struct vm_zone *namei_zone;
81
82/*
83 * vfs_init.c
84 *
85 * Allocate and fill in operations vectors.
86 *
87 * An undocumented feature of this approach to defining operations is that
88 * there can be multiple entries in vfs_opv_descs for the same operations
89 * vector. This allows third parties to extend the set of operations
90 * supported by another layer in a binary compatibile way. For example,
91 * assume that NFS needed to be modified to support Ficus. NFS has an entry
92 * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by
93 * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions)
94 * listing those new operations Ficus adds to NFS, all without modifying the
95 * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but
96 * that is a(whole)nother story.) This is a feature.
97 *
98 * Without an explicit reserve area, however, you must replace vnode_if.c
99 * and vnode_if.h when you do this, or you will be derefrencing of the
100 * end of vfs_op_descs[].  This is a flaw in the use of a structure
101 * pointer array rather than an agregate to define vfs_op_descs.  So
102 * it's not a very dynamic "feature".
103 */
104void
105vfs_opv_init(struct vnodeopv_desc **them)
106{
107	int i, j, k;
108	vop_t ***opv_desc_vector_p;
109	vop_t **opv_desc_vector;
110	struct vnodeopv_entry_desc *opve_descp;
111
112	/*
113	 * Allocate the dynamic vectors and fill them in.
114	 */
115	for (i=0; them[i]; i++) {
116		opv_desc_vector_p = them[i]->opv_desc_vector_p;
117		/*
118		 * Allocate and init the vector, if it needs it.
119		 * Also handle backwards compatibility.
120		 */
121		if (*opv_desc_vector_p == NULL) {
122			/* XXX - shouldn't be M_VNODE */
123			MALLOC(*opv_desc_vector_p, vop_t **,
124			       vfs_opv_numops * sizeof(vop_t *), M_VNODE,
125			       M_WAITOK);
126			bzero(*opv_desc_vector_p,
127			      vfs_opv_numops * sizeof(vop_t *));
128			DODEBUG(printf("vector at %x allocated\n",
129			    opv_desc_vector_p));
130		}
131		opv_desc_vector = *opv_desc_vector_p;
132		for (j=0; them[i]->opv_desc_ops[j].opve_op; j++) {
133			opve_descp = &(them[i]->opv_desc_ops[j]);
134
135			/*
136			 * Sanity check:  is this operation listed
137			 * in the list of operations?  We check this
138			 * by seeing if its offest is zero.  Since
139			 * the default routine should always be listed
140			 * first, it should be the only one with a zero
141			 * offset.  Any other operation with a zero
142			 * offset is probably not listed in
143			 * vfs_op_descs, and so is probably an error.
144			 *
145			 * A panic here means the layer programmer
146			 * has committed the all-too common bug
147			 * of adding a new operation to the layer's
148			 * list of vnode operations but
149			 * not adding the operation to the system-wide
150			 * list of supported operations.
151			 */
152			if (opve_descp->opve_op->vdesc_offset == 0 &&
153				    opve_descp->opve_op->vdesc_offset !=
154				    	VOFFSET(vop_default)) {
155				printf("operation %s not listed in %s.\n",
156				    opve_descp->opve_op->vdesc_name,
157				    "vfs_op_descs");
158				panic ("vfs_opv_init: bad operation");
159			}
160			/*
161			 * Fill in this entry.
162			 */
163			opv_desc_vector[opve_descp->opve_op->vdesc_offset] =
164					opve_descp->opve_impl;
165		}
166	}
167	/*
168	 * Finally, go back and replace unfilled routines
169	 * with their default.  (Sigh, an O(n^3) algorithm.  I
170	 * could make it better, but that'd be work, and n is small.)
171	 */
172	for (i = 0; them[i]; i++) {
173		opv_desc_vector = *(them[i]->opv_desc_vector_p);
174		/*
175		 * Force every operations vector to have a default routine.
176		 */
177		if (opv_desc_vector[VOFFSET(vop_default)]==NULL) {
178			panic("vfs_opv_init: operation vector without default routine.");
179		}
180		for (k = 0; k<vfs_opv_numops; k++)
181			if (opv_desc_vector[k] == NULL)
182				opv_desc_vector[k] =
183					opv_desc_vector[VOFFSET(vop_default)];
184	}
185}
186
187/*
188 * Initialize known vnode operations vectors.
189 */
190static void
191vfs_op_init()
192{
193	int i;
194
195	DODEBUG(printf("Vnode_interface_init.\n"));
196	DODEBUG(printf ("vfs_opv_numops=%d\n", vfs_opv_numops));
197	/*
198	 * Set all vnode vectors to a well known value.
199	 */
200	for (i = 0; vfs_opv_descs[i]; i++)
201		*(vfs_opv_descs[i]->opv_desc_vector_p) = NULL;
202	/*
203	 * assign each op to its offset
204	 *
205	 * XXX This should not be needed, but is because the per
206	 * XXX FS ops tables are not sorted according to the
207	 * XXX vnodeop_desc's offset in vfs_op_descs.  This
208	 * XXX is the same reason we have to take the hit for
209	 * XXX the static inline function calls instead of using
210	 * XXX simple macro references.
211	 */
212	for (i = 0; i < vfs_opv_numops; i++)
213		vfs_op_descs[i]->vdesc_offset = i;
214}
215
216/*
217 * Routines having to do with the management of the vnode table.
218 */
219extern struct vnodeops dead_vnodeops;
220extern struct vnodeops spec_vnodeops;
221struct vattr va_null;
222
223/*
224 * Initialize the vnode structures and initialize each file system type.
225 */
226/* ARGSUSED*/
227static void
228vfsinit(dummy)
229	void *dummy;
230{
231	struct vfsconf **vfc;
232	int maxtypenum;
233
234	namei_zone = zinit("NAMEI", MAXPATHLEN, 0, 0, 2);
235
236	/*
237	 * Initialize the vnode table
238	 */
239	vntblinit();
240	/*
241	 * Initialize the vnode name cache
242	 */
243	nchinit();
244	/*
245	 * Build vnode operation vectors.
246	 */
247	vfs_op_init();
248	vfs_opv_init(vfs_opv_descs);   /* finish the job */
249	/*
250	 * Initialize each file system type.
251	 */
252	vattr_null(&va_null);
253	maxtypenum = 0;
254	vfc = (struct vfsconf **)vfs_set.ls_items;
255	vfsconf = *vfc;		/* simulate Lite2 vfsconf array */
256	while (*vfc) {
257		struct vfsconf *vfsp = *vfc;
258
259		vfc++;
260		vfsp->vfc_next = *vfc;
261		if (maxtypenum <= vfsp->vfc_typenum)
262			maxtypenum = vfsp->vfc_typenum + 1;
263		(*vfsp->vfc_vfsops->vfs_init)(vfsp);
264	}
265	/* next vfc_typenum to be used */
266	maxvfsconf = maxtypenum;
267}
268
269