null_vfsops.c revision 7095 
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_vfsops.c	8.2 (Berkeley) 1/21/94
37 *
38 * @(#)lofs_vfsops.c	1.2 (Berkeley) 6/18/92
39 * $Id: null_vfsops.c,v 1.5 1995/03/16 18:13:31 bde Exp $
40 */
41
42/*
43 * Null Layer
44 * (See null_vnops.c for a description of what this does.)
45 */
46
47#include <sys/param.h>
48#include <sys/systm.h>
49#include <sys/kernel.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
58/*
59 * Mount null layer
60 */
61int
62nullfs_mount(mp, path, data, ndp, p)
63	struct mount *mp;
64	char *path;
65	caddr_t data;
66	struct nameidata *ndp;
67	struct proc *p;
68{
69	int error = 0;
70	struct null_args args;
71	struct vnode *lowerrootvp, *vp;
72	struct vnode *nullm_rootvp;
73	struct null_mount *xmp;
74	u_int size;
75
76#ifdef NULLFS_DIAGNOSTIC
77	printf("nullfs_mount(mp = %x)\n", mp);
78#endif
79
80	/*
81	 * Update is a no-op
82	 */
83	if (mp->mnt_flag & MNT_UPDATE) {
84		return (EOPNOTSUPP);
85		/* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, p);*/
86	}
87
88	/*
89	 * Get argument
90	 */
91	error = copyin(data, (caddr_t)&args, sizeof(struct null_args));
92	if (error)
93		return (error);
94
95	/*
96	 * Find lower node
97	 */
98	NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF,
99		UIO_USERSPACE, args.target, p);
100	error = namei(ndp);
101	if (error)
102		return (error);
103
104	/*
105	 * Sanity check on lower vnode
106	 */
107	lowerrootvp = ndp->ni_vp;
108
109	vrele(ndp->ni_dvp);
110	ndp->ni_dvp = NULL;
111
112	xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
113				M_UFSMNT, M_WAITOK);	/* XXX */
114
115	/*
116	 * Save reference to underlying FS
117	 */
118	xmp->nullm_vfs = lowerrootvp->v_mount;
119
120	/*
121	 * Save reference.  Each mount also holds
122	 * a reference on the root vnode.
123	 */
124	error = null_node_create(mp, lowerrootvp, &vp);
125	/*
126	 * Unlock the node (either the lower or the alias)
127	 */
128	VOP_UNLOCK(vp);
129	/*
130	 * Make sure the node alias worked
131	 */
132	if (error) {
133		vrele(lowerrootvp);
134		free(xmp, M_UFSMNT);	/* XXX */
135		return (error);
136	}
137
138	/*
139	 * Keep a held reference to the root vnode.
140	 * It is vrele'd in nullfs_unmount.
141	 */
142	nullm_rootvp = vp;
143	nullm_rootvp->v_flag |= VROOT;
144	xmp->nullm_rootvp = nullm_rootvp;
145	if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
146		mp->mnt_flag |= MNT_LOCAL;
147	mp->mnt_data = (qaddr_t) xmp;
148	getnewfsid(mp, MOUNT_LOFS);
149
150	(void) copyinstr(path, mp->mnt_stat.f_mntonname, MNAMELEN - 1, &size);
151	bzero(mp->mnt_stat.f_mntonname + size, MNAMELEN - size);
152	(void) copyinstr(args.target, mp->mnt_stat.f_mntfromname, MNAMELEN - 1,
153	    &size);
154	bzero(mp->mnt_stat.f_mntfromname + size, MNAMELEN - size);
155#ifdef NULLFS_DIAGNOSTIC
156	printf("nullfs_mount: lower %s, alias at %s\n",
157		mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
158#endif
159	return (0);
160}
161
162/*
163 * VFS start.  Nothing needed here - the start routine
164 * on the underlying filesystem will have been called
165 * when that filesystem was mounted.
166 */
167int
168nullfs_start(mp, flags, p)
169	struct mount *mp;
170	int flags;
171	struct proc *p;
172{
173	return (0);
174	/* return VFS_START(MOUNTTONULLMOUNT(mp)->nullm_vfs, flags, p); */
175}
176
177/*
178 * Free reference to null layer
179 */
180int
181nullfs_unmount(mp, mntflags, p)
182	struct mount *mp;
183	int mntflags;
184	struct proc *p;
185{
186	struct vnode *nullm_rootvp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
187	int error;
188	int flags = 0;
189
190#ifdef NULLFS_DIAGNOSTIC
191	printf("nullfs_unmount(mp = %x)\n", mp);
192#endif
193
194	if (mntflags & MNT_FORCE) {
195		/* lofs can never be rootfs so don't check for it */
196		if (!doforce)
197			return (EINVAL);
198		flags |= FORCECLOSE;
199	}
200
201	/*
202	 * Clear out buffer cache.  I don't think we
203	 * ever get anything cached at this level at the
204	 * moment, but who knows...
205	 */
206#if 0
207	mntflushbuf(mp, 0);
208	if (mntinvalbuf(mp, 1))
209		return (EBUSY);
210#endif
211	if (nullm_rootvp->v_usecount > 1)
212		return (EBUSY);
213	error = vflush(mp, nullm_rootvp, flags);
214	if (error)
215		return (error);
216
217#ifdef NULLFS_DIAGNOSTIC
218	vprint("alias root of lower", nullm_rootvp);
219#endif
220	/*
221	 * Release reference on underlying root vnode
222	 */
223	vrele(nullm_rootvp);
224	/*
225	 * And blow it away for future re-use
226	 */
227	vgone(nullm_rootvp);
228	/*
229	 * Finally, throw away the null_mount structure
230	 */
231	free(mp->mnt_data, M_UFSMNT);	/* XXX */
232	mp->mnt_data = 0;
233	return 0;
234}
235
236int
237nullfs_root(mp, vpp)
238	struct mount *mp;
239	struct vnode **vpp;
240{
241	struct vnode *vp;
242
243#ifdef NULLFS_DIAGNOSTIC
244	printf("nullfs_root(mp = %x, vp = %x->%x)\n", mp,
245			MOUNTTONULLMOUNT(mp)->nullm_rootvp,
246			NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)
247			);
248#endif
249
250	/*
251	 * Return locked reference to root.
252	 */
253	vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
254	VREF(vp);
255	VOP_LOCK(vp);
256	*vpp = vp;
257	return 0;
258}
259
260int
261nullfs_quotactl(mp, cmd, uid, arg, p)
262	struct mount *mp;
263	int cmd;
264	uid_t uid;
265	caddr_t arg;
266	struct proc *p;
267{
268	return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, p);
269}
270
271int
272nullfs_statfs(mp, sbp, p)
273	struct mount *mp;
274	struct statfs *sbp;
275	struct proc *p;
276{
277	int error;
278	struct statfs mstat;
279
280#ifdef NULLFS_DIAGNOSTIC
281	printf("nullfs_statfs(mp = %x, vp = %x->%x)\n", mp,
282			MOUNTTONULLMOUNT(mp)->nullm_rootvp,
283			NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp)
284			);
285#endif
286
287	bzero(&mstat, sizeof(mstat));
288
289	error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, p);
290	if (error)
291		return (error);
292
293	/* now copy across the "interesting" information and fake the rest */
294	sbp->f_type = mstat.f_type;
295	sbp->f_flags = mstat.f_flags;
296	sbp->f_bsize = mstat.f_bsize;
297	sbp->f_iosize = mstat.f_iosize;
298	sbp->f_blocks = mstat.f_blocks;
299	sbp->f_bfree = mstat.f_bfree;
300	sbp->f_bavail = mstat.f_bavail;
301	sbp->f_files = mstat.f_files;
302	sbp->f_ffree = mstat.f_ffree;
303	if (sbp != &mp->mnt_stat) {
304		bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
305		bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
306		bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
307	}
308	return (0);
309}
310
311int
312nullfs_sync(mp, waitfor, cred, p)
313	struct mount *mp;
314	int waitfor;
315	struct ucred *cred;
316	struct proc *p;
317{
318	/*
319	 * XXX - Assumes no data cached at null layer.
320	 */
321	return (0);
322}
323
324int
325nullfs_vget(mp, ino, vpp)
326	struct mount *mp;
327	ino_t ino;
328	struct vnode **vpp;
329{
330
331	return VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, vpp);
332}
333
334int
335nullfs_fhtovp(mp, fidp, nam, vpp, exflagsp, credanonp)
336	struct mount *mp;
337	struct fid *fidp;
338	struct mbuf *nam;
339	struct vnode **vpp;
340	int *exflagsp;
341	struct ucred**credanonp;
342{
343
344	return VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, nam, vpp, exflagsp,credanonp);
345}
346
347int
348nullfs_vptofh(vp, fhp)
349	struct vnode *vp;
350	struct fid *fhp;
351{
352	return VFS_VPTOFH(NULLVPTOLOWERVP(vp), fhp);
353}
354
355int nullfs_init __P((void));
356
357struct vfsops null_vfsops = {
358	nullfs_mount,
359	nullfs_start,
360	nullfs_unmount,
361	nullfs_root,
362	nullfs_quotactl,
363	nullfs_statfs,
364	nullfs_sync,
365	nullfs_vget,
366	nullfs_fhtovp,
367	nullfs_vptofh,
368	nullfs_init,
369};
370
371VFS_SET(null_vfsops, null, MOUNT_NULL, VFCF_LOOPBACK);
372