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 donated to Berkeley by
6 * Jan-Simon Pendry.
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_subr.c 8.7 (Berkeley) 5/14/95
37 *
| 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 donated to Berkeley by
6 * Jan-Simon Pendry.
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_subr.c 8.7 (Berkeley) 5/14/95
37 *
|
38 * $Id$
| 38 * $Id: null_subr.c,v 1.9 1997/02/22 09:40:21 peter Exp $
|
39 */
40
41#include <sys/param.h>
42#include <sys/systm.h>
43#include <sys/proc.h>
44#include <sys/time.h>
45#include <sys/types.h>
46#include <sys/vnode.h>
47#include <sys/mount.h>
48#include <sys/namei.h>
49#include <sys/malloc.h>
50#include <miscfs/nullfs/null.h>
51
52#define LOG2_SIZEVNODE 7 /* log2(sizeof struct vnode) */
53#define NNULLNODECACHE 16
54
55/*
56 * Null layer cache:
57 * Each cache entry holds a reference to the lower vnode
58 * along with a pointer to the alias vnode. When an
59 * entry is added the lower vnode is VREF'd. When the
60 * alias is removed the lower vnode is vrele'd.
61 */
62
63#define NULL_NHASH(vp) \
64 (&null_node_hashtbl[(((u_long)vp)>>LOG2_SIZEVNODE) & null_node_hash])
65LIST_HEAD(null_node_hashhead, null_node) *null_node_hashtbl;
66u_long null_node_hash;
67
68static int null_node_alloc __P((struct mount *mp, struct vnode *lowervp,
69 struct vnode **vpp));
70static struct vnode *
71 null_node_find __P((struct mount *mp, struct vnode *lowervp));
72
73/*
74 * Initialise cache headers
75 */
76int
77nullfs_init(vfsp)
78 struct vfsconf *vfsp;
79{
80
81#ifdef NULLFS_DIAGNOSTIC
82 printf("nullfs_init\n"); /* printed during system boot */
83#endif
84 null_node_hashtbl = hashinit(NNULLNODECACHE, M_CACHE, &null_node_hash);
85 return (0);
86}
87
88/*
89 * Return a VREF'ed alias for lower vnode if already exists, else 0.
90 */
91static struct vnode *
92null_node_find(mp, lowervp)
93 struct mount *mp;
94 struct vnode *lowervp;
95{
96 struct proc *p = curproc; /* XXX */
97 struct null_node_hashhead *hd;
98 struct null_node *a;
99 struct vnode *vp;
100
101 /*
102 * Find hash base, and then search the (two-way) linked
103 * list looking for a null_node structure which is referencing
104 * the lower vnode. If found, the increment the null_node
105 * reference count (but NOT the lower vnode's VREF counter).
106 */
107 hd = NULL_NHASH(lowervp);
108loop:
109 for (a = hd->lh_first; a != 0; a = a->null_hash.le_next) {
110 if (a->null_lowervp == lowervp && NULLTOV(a)->v_mount == mp) {
111 vp = NULLTOV(a);
112 /*
113 * We need vget for the VXLOCK
114 * stuff, but we don't want to lock
115 * the lower node.
116 */
117 if (vget(vp, 0, p)) {
118 printf ("null_node_find: vget failed.\n");
119 goto loop;
120 };
121 return (vp);
122 }
123 }
124
| 39 */
40
41#include <sys/param.h>
42#include <sys/systm.h>
43#include <sys/proc.h>
44#include <sys/time.h>
45#include <sys/types.h>
46#include <sys/vnode.h>
47#include <sys/mount.h>
48#include <sys/namei.h>
49#include <sys/malloc.h>
50#include <miscfs/nullfs/null.h>
51
52#define LOG2_SIZEVNODE 7 /* log2(sizeof struct vnode) */
53#define NNULLNODECACHE 16
54
55/*
56 * Null layer cache:
57 * Each cache entry holds a reference to the lower vnode
58 * along with a pointer to the alias vnode. When an
59 * entry is added the lower vnode is VREF'd. When the
60 * alias is removed the lower vnode is vrele'd.
61 */
62
63#define NULL_NHASH(vp) \
64 (&null_node_hashtbl[(((u_long)vp)>>LOG2_SIZEVNODE) & null_node_hash])
65LIST_HEAD(null_node_hashhead, null_node) *null_node_hashtbl;
66u_long null_node_hash;
67
68static int null_node_alloc __P((struct mount *mp, struct vnode *lowervp,
69 struct vnode **vpp));
70static struct vnode *
71 null_node_find __P((struct mount *mp, struct vnode *lowervp));
72
73/*
74 * Initialise cache headers
75 */
76int
77nullfs_init(vfsp)
78 struct vfsconf *vfsp;
79{
80
81#ifdef NULLFS_DIAGNOSTIC
82 printf("nullfs_init\n"); /* printed during system boot */
83#endif
84 null_node_hashtbl = hashinit(NNULLNODECACHE, M_CACHE, &null_node_hash);
85 return (0);
86}
87
88/*
89 * Return a VREF'ed alias for lower vnode if already exists, else 0.
90 */
91static struct vnode *
92null_node_find(mp, lowervp)
93 struct mount *mp;
94 struct vnode *lowervp;
95{
96 struct proc *p = curproc; /* XXX */
97 struct null_node_hashhead *hd;
98 struct null_node *a;
99 struct vnode *vp;
100
101 /*
102 * Find hash base, and then search the (two-way) linked
103 * list looking for a null_node structure which is referencing
104 * the lower vnode. If found, the increment the null_node
105 * reference count (but NOT the lower vnode's VREF counter).
106 */
107 hd = NULL_NHASH(lowervp);
108loop:
109 for (a = hd->lh_first; a != 0; a = a->null_hash.le_next) {
110 if (a->null_lowervp == lowervp && NULLTOV(a)->v_mount == mp) {
111 vp = NULLTOV(a);
112 /*
113 * We need vget for the VXLOCK
114 * stuff, but we don't want to lock
115 * the lower node.
116 */
117 if (vget(vp, 0, p)) {
118 printf ("null_node_find: vget failed.\n");
119 goto loop;
120 };
121 return (vp);
122 }
123 }
124
|
125 return NULL;
| 125 return NULLVP;
|
126}
127
128
129/*
130 * Make a new null_node node.
131 * Vp is the alias vnode, lofsvp is the lower vnode.
132 * Maintain a reference to (lowervp).
133 */
134static int
135null_node_alloc(mp, lowervp, vpp)
136 struct mount *mp;
137 struct vnode *lowervp;
138 struct vnode **vpp;
139{
140 struct null_node_hashhead *hd;
141 struct null_node *xp;
142 struct vnode *othervp, *vp;
143 int error;
144
145 /*
146 * Do the MALLOC before the getnewvnode since doing so afterward
147 * might cause a bogus v_data pointer to get dereferenced
148 * elsewhere if MALLOC should block.
149 */
150 MALLOC(xp, struct null_node *, sizeof(struct null_node), M_TEMP, M_WAITOK);
151
152 error = getnewvnode(VT_NULL, mp, null_vnodeop_p, vpp);
153 if (error) {
154 FREE(xp, M_TEMP);
155 return (error);
156 }
157 vp = *vpp;
158
159 vp->v_type = lowervp->v_type;
160 xp->null_vnode = vp;
161 vp->v_data = xp;
162 xp->null_lowervp = lowervp;
163 /*
164 * Before we insert our new node onto the hash chains,
165 * check to see if someone else has beaten us to it.
166 * (We could have slept in MALLOC.)
167 */
168 othervp = null_node_find(mp, lowervp);
169 if (othervp) {
170 FREE(xp, M_TEMP);
171 vp->v_type = VBAD; /* node is discarded */
172 vp->v_usecount = 0; /* XXX */
173 *vpp = othervp;
174 return 0;
175 };
176 VREF(lowervp); /* Extra VREF will be vrele'd in null_node_create */
177 hd = NULL_NHASH(lowervp);
178 LIST_INSERT_HEAD(hd, xp, null_hash);
179 return 0;
180}
181
182
183/*
184 * Try to find an existing null_node vnode refering
185 * to it, otherwise make a new null_node vnode which
186 * contains a reference to the lower vnode.
187 */
188int
189null_node_create(mp, lowervp, newvpp)
190 struct mount *mp;
191 struct vnode *lowervp;
192 struct vnode **newvpp;
193{
194 struct vnode *aliasvp;
195
196 aliasvp = null_node_find(mp, lowervp);
197 if (aliasvp) {
198 /*
199 * null_node_find has taken another reference
200 * to the alias vnode.
201 */
202#ifdef NULLFS_DIAGNOSTIC
203 vprint("null_node_create: exists", NULLTOV(ap));
204#endif
205 /* VREF(aliasvp); --- done in null_node_find */
206 } else {
207 int error;
208
209 /*
210 * Get new vnode.
211 */
212#ifdef NULLFS_DIAGNOSTIC
213 printf("null_node_create: create new alias vnode\n");
214#endif
215
216 /*
217 * Make new vnode reference the null_node.
218 */
219 error = null_node_alloc(mp, lowervp, &aliasvp);
220 if (error)
221 return error;
222
223 /*
224 * aliasvp is already VREF'd by getnewvnode()
225 */
226 }
227
228 vrele(lowervp);
229
230#ifdef DIAGNOSTIC
231 if (lowervp->v_usecount < 1) {
232 /* Should never happen... */
233 vprint ("null_node_create: alias ", aliasvp);
234 vprint ("null_node_create: lower ", lowervp);
235 panic ("null_node_create: lower has 0 usecount.");
236 };
237#endif
238
239#ifdef NULLFS_DIAGNOSTIC
240 vprint("null_node_create: alias", aliasvp);
241 vprint("null_node_create: lower", lowervp);
242#endif
243
244 *newvpp = aliasvp;
245 return (0);
246}
247#ifdef NULLFS_DIAGNOSTIC
248struct vnode *
249null_checkvp(vp, fil, lno)
250 struct vnode *vp;
251 char *fil;
252 int lno;
253{
254 struct null_node *a = VTONULL(vp);
255#ifdef notyet
256 /*
257 * Can't do this check because vop_reclaim runs
258 * with a funny vop vector.
259 */
260 if (vp->v_op != null_vnodeop_p) {
261 printf ("null_checkvp: on non-null-node\n");
262 while (null_checkvp_barrier) /*WAIT*/ ;
263 panic("null_checkvp");
264 };
265#endif
| 126}
127
128
129/*
130 * Make a new null_node node.
131 * Vp is the alias vnode, lofsvp is the lower vnode.
132 * Maintain a reference to (lowervp).
133 */
134static int
135null_node_alloc(mp, lowervp, vpp)
136 struct mount *mp;
137 struct vnode *lowervp;
138 struct vnode **vpp;
139{
140 struct null_node_hashhead *hd;
141 struct null_node *xp;
142 struct vnode *othervp, *vp;
143 int error;
144
145 /*
146 * Do the MALLOC before the getnewvnode since doing so afterward
147 * might cause a bogus v_data pointer to get dereferenced
148 * elsewhere if MALLOC should block.
149 */
150 MALLOC(xp, struct null_node *, sizeof(struct null_node), M_TEMP, M_WAITOK);
151
152 error = getnewvnode(VT_NULL, mp, null_vnodeop_p, vpp);
153 if (error) {
154 FREE(xp, M_TEMP);
155 return (error);
156 }
157 vp = *vpp;
158
159 vp->v_type = lowervp->v_type;
160 xp->null_vnode = vp;
161 vp->v_data = xp;
162 xp->null_lowervp = lowervp;
163 /*
164 * Before we insert our new node onto the hash chains,
165 * check to see if someone else has beaten us to it.
166 * (We could have slept in MALLOC.)
167 */
168 othervp = null_node_find(mp, lowervp);
169 if (othervp) {
170 FREE(xp, M_TEMP);
171 vp->v_type = VBAD; /* node is discarded */
172 vp->v_usecount = 0; /* XXX */
173 *vpp = othervp;
174 return 0;
175 };
176 VREF(lowervp); /* Extra VREF will be vrele'd in null_node_create */
177 hd = NULL_NHASH(lowervp);
178 LIST_INSERT_HEAD(hd, xp, null_hash);
179 return 0;
180}
181
182
183/*
184 * Try to find an existing null_node vnode refering
185 * to it, otherwise make a new null_node vnode which
186 * contains a reference to the lower vnode.
187 */
188int
189null_node_create(mp, lowervp, newvpp)
190 struct mount *mp;
191 struct vnode *lowervp;
192 struct vnode **newvpp;
193{
194 struct vnode *aliasvp;
195
196 aliasvp = null_node_find(mp, lowervp);
197 if (aliasvp) {
198 /*
199 * null_node_find has taken another reference
200 * to the alias vnode.
201 */
202#ifdef NULLFS_DIAGNOSTIC
203 vprint("null_node_create: exists", NULLTOV(ap));
204#endif
205 /* VREF(aliasvp); --- done in null_node_find */
206 } else {
207 int error;
208
209 /*
210 * Get new vnode.
211 */
212#ifdef NULLFS_DIAGNOSTIC
213 printf("null_node_create: create new alias vnode\n");
214#endif
215
216 /*
217 * Make new vnode reference the null_node.
218 */
219 error = null_node_alloc(mp, lowervp, &aliasvp);
220 if (error)
221 return error;
222
223 /*
224 * aliasvp is already VREF'd by getnewvnode()
225 */
226 }
227
228 vrele(lowervp);
229
230#ifdef DIAGNOSTIC
231 if (lowervp->v_usecount < 1) {
232 /* Should never happen... */
233 vprint ("null_node_create: alias ", aliasvp);
234 vprint ("null_node_create: lower ", lowervp);
235 panic ("null_node_create: lower has 0 usecount.");
236 };
237#endif
238
239#ifdef NULLFS_DIAGNOSTIC
240 vprint("null_node_create: alias", aliasvp);
241 vprint("null_node_create: lower", lowervp);
242#endif
243
244 *newvpp = aliasvp;
245 return (0);
246}
247#ifdef NULLFS_DIAGNOSTIC
248struct vnode *
249null_checkvp(vp, fil, lno)
250 struct vnode *vp;
251 char *fil;
252 int lno;
253{
254 struct null_node *a = VTONULL(vp);
255#ifdef notyet
256 /*
257 * Can't do this check because vop_reclaim runs
258 * with a funny vop vector.
259 */
260 if (vp->v_op != null_vnodeop_p) {
261 printf ("null_checkvp: on non-null-node\n");
262 while (null_checkvp_barrier) /*WAIT*/ ;
263 panic("null_checkvp");
264 };
265#endif
|
266 if (a->null_lowervp == NULL) {
| 266 if (a->null_lowervp == NULLVP) {
|
267 /* Should never happen */
268 int i; u_long *p;
269 printf("vp = %x, ZERO ptr\n", vp);
270 for (p = (u_long *) a, i = 0; i < 8; i++)
271 printf(" %x", p[i]);
272 printf("\n");
273 /* wait for debugger */
274 while (null_checkvp_barrier) /*WAIT*/ ;
275 panic("null_checkvp");
276 }
277 if (a->null_lowervp->v_usecount < 1) {
278 int i; u_long *p;
279 printf("vp = %x, unref'ed lowervp\n", vp);
280 for (p = (u_long *) a, i = 0; i < 8; i++)
281 printf(" %x", p[i]);
282 printf("\n");
283 /* wait for debugger */
284 while (null_checkvp_barrier) /*WAIT*/ ;
285 panic ("null with unref'ed lowervp");
286 };
287#ifdef notyet
288 printf("null %x/%d -> %x/%d [%s, %d]\n",
289 NULLTOV(a), NULLTOV(a)->v_usecount,
290 a->null_lowervp, a->null_lowervp->v_usecount,
291 fil, lno);
292#endif
293 return a->null_lowervp;
294}
295#endif
| 267 /* Should never happen */
268 int i; u_long *p;
269 printf("vp = %x, ZERO ptr\n", vp);
270 for (p = (u_long *) a, i = 0; i < 8; i++)
271 printf(" %x", p[i]);
272 printf("\n");
273 /* wait for debugger */
274 while (null_checkvp_barrier) /*WAIT*/ ;
275 panic("null_checkvp");
276 }
277 if (a->null_lowervp->v_usecount < 1) {
278 int i; u_long *p;
279 printf("vp = %x, unref'ed lowervp\n", vp);
280 for (p = (u_long *) a, i = 0; i < 8; i++)
281 printf(" %x", p[i]);
282 printf("\n");
283 /* wait for debugger */
284 while (null_checkvp_barrier) /*WAIT*/ ;
285 panic ("null with unref'ed lowervp");
286 };
287#ifdef notyet
288 printf("null %x/%d -> %x/%d [%s, %d]\n",
289 NULLTOV(a), NULLTOV(a)->v_usecount,
290 a->null_lowervp, a->null_lowervp->v_usecount,
291 fil, lno);
292#endif
293 return a->null_lowervp;
294}
295#endif
|