null_vfsops.c revision 1.18 
1/*	$NetBSD: null_vfsops.c,v 1.18 1998/02/18 07:05:48 thorpej Exp $	*/
2
3/*
4 * Copyright (c) 1992, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software donated to Berkeley by
8 * Jan-Simon Pendry.
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 *	from: Id: lofs_vfsops.c,v 1.9 1992/05/30 10:26:24 jsp Exp
39 *	from: @(#)lofs_vfsops.c	1.2 (Berkeley) 6/18/92
40 *	@(#)null_vfsops.c	8.2 (Berkeley) 1/21/94
41 */
42
43/*
44 * Null Layer
45 * (See null_vnops.c for a description of what this does.)
46 */
47
48#include <sys/param.h>
49#include <sys/systm.h>
50#include <sys/time.h>
51#include <sys/types.h>
52#include <sys/vnode.h>
53#include <sys/mount.h>
54#include <sys/namei.h>
55#include <sys/malloc.h>
56#include <miscfs/nullfs/null.h>
57
58int	nullfs_mount __P((struct mount *, const char *, void *,
59			  struct nameidata *, struct proc *));
60int	nullfs_start __P((struct mount *, int, struct proc *));
61int	nullfs_unmount __P((struct mount *, int, struct proc *));
62int	nullfs_root __P((struct mount *, struct vnode **));
63int	nullfs_quotactl __P((struct mount *, int, uid_t, caddr_t,
64			     struct proc *));
65int	nullfs_statfs __P((struct mount *, struct statfs *, struct proc *));
66int	nullfs_sync __P((struct mount *, int, struct ucred *, struct proc *));
67int	nullfs_vget __P((struct mount *, ino_t, struct vnode **));
68int	nullfs_fhtovp __P((struct mount *, struct fid *, struct mbuf *,
69			   struct vnode **, int *, struct ucred **));
70int	nullfs_vptofh __P((struct vnode *, struct fid *));
71/*
72 * Mount null layer
73 */
74int
75nullfs_mount(mp, path, data, ndp, p)
76	struct mount *mp;
77	const char *path;
78	void *data;
79	struct nameidata *ndp;
80	struct proc *p;
81{
82	int error = 0;
83	struct null_args args;
84	struct vnode *lowerrootvp, *vp;
85	struct vnode *nullm_rootvp;
86	struct null_mount *xmp;
87	size_t size;
88
89#ifdef NULLFS_DIAGNOSTIC
90	printf("nullfs_mount(mp = %p)\n", mp);
91#endif
92
93	/*
94	 * Update is a no-op
95	 */
96	if (mp->mnt_flag & MNT_UPDATE) {
97		return (EOPNOTSUPP);
98		/* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/
99	}
100
101	/*
102	 * Get argument
103	 */
104	error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
105	if (error)
106		return (error);
107
108	/*
109	 * Find lower node
110	 */
111	NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF,
112		UIO_USERSPACE, args.target, p);
113	if ((error = namei(ndp)) != 0)
114		return (error);
115
116	/*
117	 * Sanity check on lower vnode
118	 */
119	lowerrootvp = ndp->ni_vp;
120
121	vrele(ndp->ni_dvp);
122	ndp->ni_dvp = NULL;
123
124	xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
125				M_UFSMNT, M_WAITOK);	/* XXX */
126
127	/*
128	 * Save reference to underlying FS
129	 */
130	xmp->nullm_vfs = lowerrootvp->v_mount;
131
132	/*
133	 * Save reference.  Each mount also holds
134	 * a reference on the root vnode.
135	 */
136	error = null_node_create(mp, lowerrootvp, &vp, 1);
137	/*
138	 * Unlock the node (either the lower or the alias)
139	 */
140	VOP_UNLOCK(vp);
141	/*
142	 * Make sure the node alias worked
143	 */
144	if (error) {
145		vrele(lowerrootvp);
146		free(xmp, M_UFSMNT);	/* XXX */
147		return (error);
148	}
149
150	/*
151	 * Keep a held reference to the root vnode.
152	 * It is vrele'd in nullfs_unmount.
153	 */
154	nullm_rootvp = vp;
155	nullm_rootvp->v_flag |= VROOT;
156	xmp->nullm_rootvp = nullm_rootvp;
157	if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
158		mp->mnt_flag |= MNT_LOCAL;
159	mp->mnt_data = (qaddr_t) xmp;
160	getnewfsid(mp, makefstype(MOUNT_NULL));
161
162	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
163	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
164	(void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
165	    &size);
166	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
167#ifdef NULLFS_DIAGNOSTIC
168	printf("nullfs_mount: lower %s, alias at %s\n",
169	    mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
170#endif
171	return (0);
172}
173
174/*
175 * VFS start.  Nothing needed here - the start routine
176 * on the underlying filesystem will have been called
177 * when that filesystem was mounted.
178 */
179int
180nullfs_start(mp, flags, p)
181	struct mount *mp;
182	int flags;
183	struct proc *p;
184{
185
186	return (0);
187	/* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */
188}
189
190/*
191 * Free reference to null layer
192 */
193int
194nullfs_unmount(mp, mntflags, p)
195	struct mount *mp;
196	int mntflags;
197	struct proc *p;
198{
199	struct vnode *nullm_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
200	int error;
201	int flags = 0;
202	extern int doforce;
203
204#ifdef NULLFS_DIAGNOSTIC
205	printf("nullfs_unmount(mp = %p)\n", mp);
206#endif
207
208	if (mntflags & MNT_FORCE) {
209		/* lofs can never be rootfs so don't check for it */
210		if (!doforce)
211			return (EINVAL);
212		flags |= FORCECLOSE;
213	}
214
215	/*
216	 * Clear out buffer cache.  I don't think we
217	 * ever get anything cached at this level at the
218	 * moment, but who knows...
219	 */
220#if 0
221	mntflushbuf(mp, 0);
222	if (mntinvalbuf(mp, 1))
223		return (EBUSY);
224#endif
225	if (nullm_rootvp->v_usecount > 1)
226		return (EBUSY);
227	if ((error = vflush(mp, nullm_rootvp, flags)) != 0)
228		return (error);
229
230#ifdef NULLFS_DIAGNOSTIC
231	vprint("alias root of lower", nullm_rootvp);
232#endif
233	/*
234	 * Release reference on underlying root vnode
235	 */
236	vrele(nullm_rootvp);
237	/*
238	 * And blow it away for future re-use
239	 */
240	vgone(nullm_rootvp);
241	/*
242	 * Finally, throw away the null_mount structure
243	 */
244	free(mp->mnt_data, M_UFSMNT);	/* XXX */
245	mp->mnt_data = 0;
246	return 0;
247}
248
249int
250nullfs_root(mp, vpp)
251	struct mount *mp;
252	struct vnode **vpp;
253{
254	struct vnode *vp;
255
256#ifdef NULLFS_DIAGNOSTIC
257	printf("nullfs_root(mp = %p, vp = %p->%p)\n", mp,
258	    MOUNTTONULLMOUNT(mp)->nullm_rootvp,
259	    NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
260#endif
261
262	/*
263	 * Return locked reference to root.
264	 */
265	vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
266	VREF(vp);
267	VOP_LOCK(vp);
268	*vpp = vp;
269	return 0;
270}
271
272int
273nullfs_quotactl(mp, cmd, uid, arg, p)
274	struct mount *mp;
275	int cmd;
276	uid_t uid;
277	caddr_t arg;
278	struct proc *p;
279{
280
281	return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p);
282}
283
284int
285nullfs_statfs(mp, sbp, p)
286	struct mount *mp;
287	struct statfs *sbp;
288	struct proc *p;
289{
290	int error;
291	struct statfs mstat;
292
293#ifdef NULLFS_DIAGNOSTIC
294	printf("nullfs_statfs(mp = %p, vp = %p->%p)\n", mp,
295	    MOUNTTONULLMOUNT(mp)->nullm_rootvp,
296	    NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
297#endif
298
299	bzero(&mstat, sizeof(mstat));
300
301	error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p);
302	if (error)
303		return (error);
304
305	/* now copy across the "interesting" information and fake the rest */
306	sbp->f_type = mstat.f_type;
307	sbp->f_flags = mstat.f_flags;
308	sbp->f_bsize = mstat.f_bsize;
309	sbp->f_iosize = mstat.f_iosize;
310	sbp->f_blocks = mstat.f_blocks;
311	sbp->f_bfree = mstat.f_bfree;
312	sbp->f_bavail = mstat.f_bavail;
313	sbp->f_files = mstat.f_files;
314	sbp->f_ffree = mstat.f_ffree;
315	if (sbp != &mp->mnt_stat) {
316		bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
317		bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
318		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
319	}
320	strncpy(sbp->f_fstypename, mp->mnt_op->vfs_name, MFSNAMELEN);
321	return (0);
322}
323
324int
325nullfs_sync(mp, waitfor, cred, p)
326	struct mount *mp;
327	int waitfor;
328	struct ucred *cred;
329	struct proc *p;
330{
331
332	/*
333	 * XXX - Assumes no data cached at null layer.
334	 */
335	return (0);
336}
337
338int
339nullfs_vget(mp, ino, vpp)
340	struct mount *mp;
341	ino_t ino;
342	struct vnode **vpp;
343{
344
345	return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp);
346}
347
348int
349nullfs_fhtovp(mp, fidp, nam, vpp, exflagsp, credanonp)
350	struct mount *mp;
351	struct fid *fidp;
352	struct mbuf *nam;
353	struct vnode **vpp;
354	int *exflagsp;
355	struct ucred**credanonp;
356{
357
358	return (EOPNOTSUPP);
359}
360
361int
362nullfs_vptofh(vp, fhp)
363	struct vnode *vp;
364	struct fid *fhp;
365{
366
367	return (EOPNOTSUPP);
368}
369
370extern struct vnodeopv_desc nullfs_vnodeop_opv_desc;
371
372struct vnodeopv_desc *nullfs_vnodeopv_descs[] = {
373	&nullfs_vnodeop_opv_desc,
374	NULL,
375};
376
377struct vfsops nullfs_vfsops = {
378	MOUNT_NULL,
379	nullfs_mount,
380	nullfs_start,
381	nullfs_unmount,
382	nullfs_root,
383	nullfs_quotactl,
384	nullfs_statfs,
385	nullfs_sync,
386	nullfs_vget,
387	nullfs_fhtovp,
388	nullfs_vptofh,
389	nullfs_init,
390	NULL,				/* vfs_mountroot */
391	nullfs_vnodeopv_descs,
392};
393