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 *
|
66
67static int null_node_alloc __P((struct mount *mp, struct vnode *lowervp,
68 struct vnode **vpp));
69static struct vnode *
70 null_node_find __P((struct mount *mp, struct vnode *lowervp));
71
72/*
73 * Initialise cache headers
74 */
75int
76nullfs_init(vfsp)
77 struct vfsconf *vfsp;
78{
79
80#ifdef NULLFS_DIAGNOSTIC
81 printf("nullfs_init\n"); /* printed during system boot */
82#endif
83 null_node_hashtbl = hashinit(NNULLNODECACHE, M_CACHE, &null_node_hash);
84 return (0);
85}
86
87/*
88 * Return a VREF'ed alias for lower vnode if already exists, else 0.
89 */
90static struct vnode *
91null_node_find(mp, lowervp)
92 struct mount *mp;
93 struct vnode *lowervp;
94{
95 struct proc *p = curproc; /* XXX */
96 struct null_node_hashhead *hd;
97 struct null_node *a;
98 struct vnode *vp;
99
100 /*
101 * Find hash base, and then search the (two-way) linked
102 * list looking for a null_node structure which is referencing
103 * the lower vnode. If found, the increment the null_node
104 * reference count (but NOT the lower vnode's VREF counter).
105 */
106 hd = NULL_NHASH(lowervp);
107loop:
108 for (a = hd->lh_first; a != 0; a = a->null_hash.le_next) {
109 if (a->null_lowervp == lowervp && NULLTOV(a)->v_mount == mp) {
110 vp = NULLTOV(a);
111 /*
112 * We need vget for the VXLOCK
113 * stuff, but we don't want to lock
114 * the lower node.
115 */
116 if (vget(vp, 0, p)) {
117 printf ("null_node_find: vget failed.\n");
118 goto loop;
119 };
120 return (vp);
121 }
122 }
123
124 return NULLVP;
125}
126
127
128/*
129 * Make a new null_node node.
130 * Vp is the alias vnode, lofsvp is the lower vnode.
131 * Maintain a reference to (lowervp).
132 */
133static int
134null_node_alloc(mp, lowervp, vpp)
135 struct mount *mp;
136 struct vnode *lowervp;
137 struct vnode **vpp;
138{
139 struct null_node_hashhead *hd;
140 struct null_node *xp;
141 struct vnode *othervp, *vp;
142 int error;
143
144 /*
145 * Do the MALLOC before the getnewvnode since doing so afterward
146 * might cause a bogus v_data pointer to get dereferenced
147 * elsewhere if MALLOC should block.
148 */
149 MALLOC(xp, struct null_node *, sizeof(struct null_node), M_TEMP, M_WAITOK);
150
151 error = getnewvnode(VT_NULL, mp, null_vnodeop_p, vpp);
152 if (error) {
153 FREE(xp, M_TEMP);
154 return (error);
155 }
156 vp = *vpp;
157
158 vp->v_type = lowervp->v_type;
159 xp->null_vnode = vp;
160 vp->v_data = xp;
161 xp->null_lowervp = lowervp;
162 /*
163 * Before we insert our new node onto the hash chains,
164 * check to see if someone else has beaten us to it.
165 * (We could have slept in MALLOC.)
166 */
167 othervp = null_node_find(mp, lowervp);
168 if (othervp) {
169 FREE(xp, M_TEMP);
170 vp->v_type = VBAD; /* node is discarded */
171 vp->v_usecount = 0; /* XXX */
172 *vpp = othervp;
173 return 0;
174 };
175 VREF(lowervp); /* Extra VREF will be vrele'd in null_node_create */
176 hd = NULL_NHASH(lowervp);
177 LIST_INSERT_HEAD(hd, xp, null_hash);
178 return 0;
179}
180
181
182/*
183 * Try to find an existing null_node vnode refering
184 * to it, otherwise make a new null_node vnode which
185 * contains a reference to the lower vnode.
186 */
187int
188null_node_create(mp, lowervp, newvpp)
189 struct mount *mp;
190 struct vnode *lowervp;
191 struct vnode **newvpp;
192{
193 struct vnode *aliasvp;
194
195 aliasvp = null_node_find(mp, lowervp);
196 if (aliasvp) {
197 /*
198 * null_node_find has taken another reference
199 * to the alias vnode.
200 */
201#ifdef NULLFS_DIAGNOSTIC
202 vprint("null_node_create: exists", aliasvp);
203#endif
204 /* VREF(aliasvp); --- done in null_node_find */
205 } else {
206 int error;
207
208 /*
209 * Get new vnode.
210 */
211#ifdef NULLFS_DIAGNOSTIC
212 printf("null_node_create: create new alias vnode\n");
213#endif
214
215 /*
216 * Make new vnode reference the null_node.
217 */
218 error = null_node_alloc(mp, lowervp, &aliasvp);
219 if (error)
220 return error;
221
222 /*
223 * aliasvp is already VREF'd by getnewvnode()
224 */
225 }
226
227 vrele(lowervp);
228
229#ifdef DIAGNOSTIC
230 if (lowervp->v_usecount < 1) {
231 /* Should never happen... */
232 vprint ("null_node_create: alias ", aliasvp);
233 vprint ("null_node_create: lower ", lowervp);
234 panic ("null_node_create: lower has 0 usecount.");
235 };
236#endif
237
238#ifdef NULLFS_DIAGNOSTIC
239 vprint("null_node_create: alias", aliasvp);
240 vprint("null_node_create: lower", lowervp);
241#endif
242
243 *newvpp = aliasvp;
244 return (0);
245}
246
247#ifdef NULLFS_DIAGNOSTIC
248#include "opt_ddb.h"
249
250#ifdef DDB
251#define null_checkvp_barrier 1
252#else
253#define null_checkvp_barrier 0
254#endif
255
256struct vnode *
257null_checkvp(vp, fil, lno)
258 struct vnode *vp;
259 char *fil;
260 int lno;
261{
262 struct null_node *a = VTONULL(vp);
263#ifdef notyet
264 /*
265 * Can't do this check because vop_reclaim runs
266 * with a funny vop vector.
267 */
268 if (vp->v_op != null_vnodeop_p) {
269 printf ("null_checkvp: on non-null-node\n");
270 while (null_checkvp_barrier) /*WAIT*/ ;
271 panic("null_checkvp");
272 };
273#endif
274 if (a->null_lowervp == NULLVP) {
275 /* Should never happen */
276 int i; u_long *p;
277 printf("vp = %x, ZERO ptr\n", vp);
278 for (p = (u_long *) a, i = 0; i < 8; i++)
279 printf(" %x", p[i]);
280 printf("\n");
281 /* wait for debugger */
282 while (null_checkvp_barrier) /*WAIT*/ ;
283 panic("null_checkvp");
284 }
285 if (a->null_lowervp->v_usecount < 1) {
286 int i; u_long *p;
287 printf("vp = %x, unref'ed lowervp\n", vp);
288 for (p = (u_long *) a, i = 0; i < 8; i++)
289 printf(" %x", p[i]);
290 printf("\n");
291 /* wait for debugger */
292 while (null_checkvp_barrier) /*WAIT*/ ;
293 panic ("null with unref'ed lowervp");
294 };
295#ifdef notyet
296 printf("null %x/%d -> %x/%d [%s, %d]\n",
297 NULLTOV(a), NULLTOV(a)->v_usecount,
298 a->null_lowervp, a->null_lowervp->v_usecount,
299 fil, lno);
300#endif
301 return a->null_lowervp;
302}
303#endif
| 66
67static int null_node_alloc __P((struct mount *mp, struct vnode *lowervp,
68 struct vnode **vpp));
69static struct vnode *
70 null_node_find __P((struct mount *mp, struct vnode *lowervp));
71
72/*
73 * Initialise cache headers
74 */
75int
76nullfs_init(vfsp)
77 struct vfsconf *vfsp;
78{
79
80#ifdef NULLFS_DIAGNOSTIC
81 printf("nullfs_init\n"); /* printed during system boot */
82#endif
83 null_node_hashtbl = hashinit(NNULLNODECACHE, M_CACHE, &null_node_hash);
84 return (0);
85}
86
87/*
88 * Return a VREF'ed alias for lower vnode if already exists, else 0.
89 */
90static struct vnode *
91null_node_find(mp, lowervp)
92 struct mount *mp;
93 struct vnode *lowervp;
94{
95 struct proc *p = curproc; /* XXX */
96 struct null_node_hashhead *hd;
97 struct null_node *a;
98 struct vnode *vp;
99
100 /*
101 * Find hash base, and then search the (two-way) linked
102 * list looking for a null_node structure which is referencing
103 * the lower vnode. If found, the increment the null_node
104 * reference count (but NOT the lower vnode's VREF counter).
105 */
106 hd = NULL_NHASH(lowervp);
107loop:
108 for (a = hd->lh_first; a != 0; a = a->null_hash.le_next) {
109 if (a->null_lowervp == lowervp && NULLTOV(a)->v_mount == mp) {
110 vp = NULLTOV(a);
111 /*
112 * We need vget for the VXLOCK
113 * stuff, but we don't want to lock
114 * the lower node.
115 */
116 if (vget(vp, 0, p)) {
117 printf ("null_node_find: vget failed.\n");
118 goto loop;
119 };
120 return (vp);
121 }
122 }
123
124 return NULLVP;
125}
126
127
128/*
129 * Make a new null_node node.
130 * Vp is the alias vnode, lofsvp is the lower vnode.
131 * Maintain a reference to (lowervp).
132 */
133static int
134null_node_alloc(mp, lowervp, vpp)
135 struct mount *mp;
136 struct vnode *lowervp;
137 struct vnode **vpp;
138{
139 struct null_node_hashhead *hd;
140 struct null_node *xp;
141 struct vnode *othervp, *vp;
142 int error;
143
144 /*
145 * Do the MALLOC before the getnewvnode since doing so afterward
146 * might cause a bogus v_data pointer to get dereferenced
147 * elsewhere if MALLOC should block.
148 */
149 MALLOC(xp, struct null_node *, sizeof(struct null_node), M_TEMP, M_WAITOK);
150
151 error = getnewvnode(VT_NULL, mp, null_vnodeop_p, vpp);
152 if (error) {
153 FREE(xp, M_TEMP);
154 return (error);
155 }
156 vp = *vpp;
157
158 vp->v_type = lowervp->v_type;
159 xp->null_vnode = vp;
160 vp->v_data = xp;
161 xp->null_lowervp = lowervp;
162 /*
163 * Before we insert our new node onto the hash chains,
164 * check to see if someone else has beaten us to it.
165 * (We could have slept in MALLOC.)
166 */
167 othervp = null_node_find(mp, lowervp);
168 if (othervp) {
169 FREE(xp, M_TEMP);
170 vp->v_type = VBAD; /* node is discarded */
171 vp->v_usecount = 0; /* XXX */
172 *vpp = othervp;
173 return 0;
174 };
175 VREF(lowervp); /* Extra VREF will be vrele'd in null_node_create */
176 hd = NULL_NHASH(lowervp);
177 LIST_INSERT_HEAD(hd, xp, null_hash);
178 return 0;
179}
180
181
182/*
183 * Try to find an existing null_node vnode refering
184 * to it, otherwise make a new null_node vnode which
185 * contains a reference to the lower vnode.
186 */
187int
188null_node_create(mp, lowervp, newvpp)
189 struct mount *mp;
190 struct vnode *lowervp;
191 struct vnode **newvpp;
192{
193 struct vnode *aliasvp;
194
195 aliasvp = null_node_find(mp, lowervp);
196 if (aliasvp) {
197 /*
198 * null_node_find has taken another reference
199 * to the alias vnode.
200 */
201#ifdef NULLFS_DIAGNOSTIC
202 vprint("null_node_create: exists", aliasvp);
203#endif
204 /* VREF(aliasvp); --- done in null_node_find */
205 } else {
206 int error;
207
208 /*
209 * Get new vnode.
210 */
211#ifdef NULLFS_DIAGNOSTIC
212 printf("null_node_create: create new alias vnode\n");
213#endif
214
215 /*
216 * Make new vnode reference the null_node.
217 */
218 error = null_node_alloc(mp, lowervp, &aliasvp);
219 if (error)
220 return error;
221
222 /*
223 * aliasvp is already VREF'd by getnewvnode()
224 */
225 }
226
227 vrele(lowervp);
228
229#ifdef DIAGNOSTIC
230 if (lowervp->v_usecount < 1) {
231 /* Should never happen... */
232 vprint ("null_node_create: alias ", aliasvp);
233 vprint ("null_node_create: lower ", lowervp);
234 panic ("null_node_create: lower has 0 usecount.");
235 };
236#endif
237
238#ifdef NULLFS_DIAGNOSTIC
239 vprint("null_node_create: alias", aliasvp);
240 vprint("null_node_create: lower", lowervp);
241#endif
242
243 *newvpp = aliasvp;
244 return (0);
245}
246
247#ifdef NULLFS_DIAGNOSTIC
248#include "opt_ddb.h"
249
250#ifdef DDB
251#define null_checkvp_barrier 1
252#else
253#define null_checkvp_barrier 0
254#endif
255
256struct vnode *
257null_checkvp(vp, fil, lno)
258 struct vnode *vp;
259 char *fil;
260 int lno;
261{
262 struct null_node *a = VTONULL(vp);
263#ifdef notyet
264 /*
265 * Can't do this check because vop_reclaim runs
266 * with a funny vop vector.
267 */
268 if (vp->v_op != null_vnodeop_p) {
269 printf ("null_checkvp: on non-null-node\n");
270 while (null_checkvp_barrier) /*WAIT*/ ;
271 panic("null_checkvp");
272 };
273#endif
274 if (a->null_lowervp == NULLVP) {
275 /* Should never happen */
276 int i; u_long *p;
277 printf("vp = %x, ZERO ptr\n", vp);
278 for (p = (u_long *) a, i = 0; i < 8; i++)
279 printf(" %x", p[i]);
280 printf("\n");
281 /* wait for debugger */
282 while (null_checkvp_barrier) /*WAIT*/ ;
283 panic("null_checkvp");
284 }
285 if (a->null_lowervp->v_usecount < 1) {
286 int i; u_long *p;
287 printf("vp = %x, unref'ed lowervp\n", vp);
288 for (p = (u_long *) a, i = 0; i < 8; i++)
289 printf(" %x", p[i]);
290 printf("\n");
291 /* wait for debugger */
292 while (null_checkvp_barrier) /*WAIT*/ ;
293 panic ("null with unref'ed lowervp");
294 };
295#ifdef notyet
296 printf("null %x/%d -> %x/%d [%s, %d]\n",
297 NULLTOV(a), NULLTOV(a)->v_usecount,
298 a->null_lowervp, a->null_lowervp->v_usecount,
299 fil, lno);
300#endif
301 return a->null_lowervp;
302}
303#endif
|