umap_vfsops.c revision 1.90 
1/*	$NetBSD: umap_vfsops.c,v 1.90 2014/02/25 18:30:12 pooka 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 * the 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. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 *	from: @(#)null_vfsops.c       1.5 (Berkeley) 7/10/92
35 *	@(#)umap_vfsops.c	8.8 (Berkeley) 5/14/95
36 */
37
38/*
39 * Umap Layer
40 * (See mount_umap(8) for a description of this layer.)
41 */
42
43#include <sys/cdefs.h>
44__KERNEL_RCSID(0, "$NetBSD: umap_vfsops.c,v 1.90 2014/02/25 18:30:12 pooka Exp $");
45
46#include <sys/param.h>
47#include <sys/systm.h>
48#include <sys/sysctl.h>
49#include <sys/proc.h>
50#include <sys/time.h>
51#include <sys/vnode.h>
52#include <sys/mount.h>
53#include <sys/namei.h>
54#include <sys/malloc.h>
55#include <sys/kauth.h>
56#include <sys/module.h>
57
58#include <miscfs/umapfs/umap.h>
59#include <miscfs/genfs/layer_extern.h>
60
61MODULE(MODULE_CLASS_VFS, umap, "layerfs");
62
63VFS_PROTOS(umapfs);
64
65static struct sysctllog *umapfs_sysctl_log;
66
67/*
68 * Mount umap layer
69 */
70int
71umapfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
72{
73	struct lwp *l = curlwp;
74	struct pathbuf *pb;
75	struct nameidata nd;
76	struct umap_args *args = data;
77	struct vnode *lowerrootvp, *vp;
78	struct umap_mount *amp;
79	int error;
80#ifdef UMAPFS_DIAGNOSTIC
81	int i;
82#endif
83
84	if (*data_len < sizeof *args)
85		return EINVAL;
86
87	if (mp->mnt_flag & MNT_GETARGS) {
88		amp = MOUNTTOUMAPMOUNT(mp);
89		if (amp == NULL)
90			return EIO;
91		args->la.target = NULL;
92		args->nentries = amp->info_nentries;
93		args->gnentries = amp->info_gnentries;
94		*data_len = sizeof *args;
95		return 0;
96	}
97
98	/* only for root */
99	error = kauth_authorize_system(l->l_cred, KAUTH_SYSTEM_MOUNT,
100	    KAUTH_REQ_SYSTEM_MOUNT_UMAP, NULL, NULL, NULL);
101	if (error)
102		return error;
103
104#ifdef UMAPFS_DIAGNOSTIC
105	printf("umapfs_mount(mp = %p)\n", mp);
106#endif
107
108	/*
109	 * Update is not supported
110	 */
111	if (mp->mnt_flag & MNT_UPDATE)
112		return EOPNOTSUPP;
113
114	/*
115	 * Find lower node
116	 */
117	error = pathbuf_copyin(args->umap_target, &pb);
118	if (error) {
119		return error;
120	}
121	NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, pb);
122	if ((error = namei(&nd)) != 0) {
123		pathbuf_destroy(pb);
124		return error;
125	}
126
127	/*
128	 * Sanity check on lower vnode
129	 */
130	lowerrootvp = nd.ni_vp;
131	pathbuf_destroy(pb);
132#ifdef UMAPFS_DIAGNOSTIC
133	printf("vp = %p, check for VDIR...\n", lowerrootvp);
134#endif
135
136	if (lowerrootvp->v_type != VDIR) {
137		vput(lowerrootvp);
138		return (EINVAL);
139	}
140
141#ifdef UMAPFS_DIAGNOSTIC
142	printf("mp = %p\n", mp);
143#endif
144
145	amp = kmem_zalloc(sizeof(struct umap_mount), KM_SLEEP);
146	mp->mnt_data = amp;
147	amp->umapm_vfs = lowerrootvp->v_mount;
148	if (amp->umapm_vfs->mnt_flag & MNT_LOCAL)
149		mp->mnt_flag |= MNT_LOCAL;
150
151	/*
152	 * Now copy in the number of entries and maps for umap mapping.
153	 */
154	if (args->nentries > MAPFILEENTRIES || args->gnentries > GMAPFILEENTRIES) {
155		vput(lowerrootvp);
156		return (error);
157	}
158
159	amp->info_nentries = args->nentries;
160	amp->info_gnentries = args->gnentries;
161	error = copyin(args->mapdata, amp->info_mapdata,
162	    2*sizeof(u_long)*args->nentries);
163	if (error) {
164		vput(lowerrootvp);
165		return (error);
166	}
167
168#ifdef UMAPFS_DIAGNOSTIC
169	printf("umap_mount:nentries %d\n",args->nentries);
170	for (i = 0; i < args->nentries; i++)
171		printf("   %ld maps to %ld\n", amp->info_mapdata[i][0],
172	 	    amp->info_mapdata[i][1]);
173#endif
174
175	error = copyin(args->gmapdata, amp->info_gmapdata,
176	    2*sizeof(u_long)*args->gnentries);
177	if (error) {
178		vput(lowerrootvp);
179		return (error);
180	}
181
182#ifdef UMAPFS_DIAGNOSTIC
183	printf("umap_mount:gnentries %d\n",args->gnentries);
184	for (i = 0; i < args->gnentries; i++)
185		printf("\tgroup %ld maps to %ld\n",
186		    amp->info_gmapdata[i][0],
187	 	    amp->info_gmapdata[i][1]);
188#endif
189
190	/*
191	 * Make sure the mount point's sufficiently initialized
192	 * that the node create call will work.
193	 */
194	vfs_getnewfsid(mp);
195	amp->umapm_size = sizeof(struct umap_node);
196	amp->umapm_tag = VT_UMAP;
197	amp->umapm_bypass = umap_bypass;
198	amp->umapm_alloc = layer_node_alloc;	/* the default alloc is fine */
199	amp->umapm_vnodeop_p = umap_vnodeop_p;
200	mutex_init(&amp->umapm_hashlock, MUTEX_DEFAULT, IPL_NONE);
201	amp->umapm_node_hashtbl = hashinit(NUMAPNODECACHE, HASH_LIST, true,
202	    &amp->umapm_node_hash);
203
204
205	/*
206	 * fix up umap node for root vnode.
207	 */
208	VOP_UNLOCK(lowerrootvp);
209	error = layer_node_create(mp, lowerrootvp, &vp);
210	/*
211	 * Make sure the node alias worked
212	 */
213	if (error) {
214		vrele(lowerrootvp);
215		hashdone(amp->umapm_node_hashtbl, HASH_LIST,
216		    amp->umapm_node_hash);
217		kmem_free(amp, sizeof(struct umap_mount));
218		return error;
219	}
220
221	/*
222	 * Keep a held reference to the root vnode.
223	 * It is vrele'd in umapfs_unmount.
224	 */
225	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
226	vp->v_vflag |= VV_ROOT;
227	amp->umapm_rootvp = vp;
228	VOP_UNLOCK(vp);
229
230	error = set_statvfs_info(path, UIO_USERSPACE, args->umap_target,
231	    UIO_USERSPACE, mp->mnt_op->vfs_name, mp, l);
232#ifdef UMAPFS_DIAGNOSTIC
233	printf("umapfs_mount: lower %s, alias at %s\n",
234		mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
235#endif
236	return error;
237}
238
239/*
240 * Free reference to umap layer
241 */
242int
243umapfs_unmount(struct mount *mp, int mntflags)
244{
245	struct umap_mount *amp = MOUNTTOUMAPMOUNT(mp);
246	struct vnode *rtvp = amp->umapm_rootvp;
247	int error;
248	int flags = 0;
249
250#ifdef UMAPFS_DIAGNOSTIC
251	printf("umapfs_unmount(mp = %p)\n", mp);
252#endif
253
254	if (mntflags & MNT_FORCE)
255		flags |= FORCECLOSE;
256
257	if (rtvp->v_usecount > 1 && (mntflags & MNT_FORCE) == 0)
258		return (EBUSY);
259	if ((error = vflush(mp, rtvp, flags)) != 0)
260		return (error);
261
262#ifdef UMAPFS_DIAGNOSTIC
263	vprint("alias root of lower", rtvp);
264#endif
265	/*
266	 * Blow it away for future re-use
267	 */
268	vgone(rtvp);
269	/*
270	 * Finally, throw away the umap_mount structure
271	 */
272	mutex_destroy(&amp->umapm_hashlock);
273	hashdone(amp->umapm_node_hashtbl, HASH_LIST, amp->umapm_node_hash);
274	kmem_free(amp, sizeof(struct umap_mount));
275	mp->mnt_data = NULL;
276	return 0;
277}
278
279extern const struct vnodeopv_desc umapfs_vnodeop_opv_desc;
280
281const struct vnodeopv_desc * const umapfs_vnodeopv_descs[] = {
282	&umapfs_vnodeop_opv_desc,
283	NULL,
284};
285
286struct vfsops umapfs_vfsops = {
287	MOUNT_UMAP,
288	sizeof (struct umap_args),
289	umapfs_mount,
290	layerfs_start,
291	umapfs_unmount,
292	layerfs_root,
293	layerfs_quotactl,
294	layerfs_statvfs,
295	layerfs_sync,
296	layerfs_vget,
297	layerfs_fhtovp,
298	layerfs_vptofh,
299	layerfs_init,
300	NULL,
301	layerfs_done,
302	NULL,				/* vfs_mountroot */
303	layerfs_snapshot,
304	vfs_stdextattrctl,
305	(void *)eopnotsupp,		/* vfs_suspendctl */
306	layerfs_renamelock_enter,
307	layerfs_renamelock_exit,
308	(void *)eopnotsupp,
309	umapfs_vnodeopv_descs,
310	0,				/* vfs_refcount */
311	{ NULL, NULL },
312};
313
314static int
315umap_modcmd(modcmd_t cmd, void *arg)
316{
317	int error;
318
319	switch (cmd) {
320	case MODULE_CMD_INIT:
321		error = vfs_attach(&umapfs_vfsops);
322		if (error != 0)
323			break;
324		sysctl_createv(&umapfs_sysctl_log, 0, NULL, NULL,
325			       CTLFLAG_PERMANENT,
326			       CTLTYPE_NODE, "umap",
327			       SYSCTL_DESCR("UID/GID remapping file system"),
328			       NULL, 0, NULL, 0,
329			       CTL_VFS, 10, CTL_EOL);
330		/*
331		 * XXX the "10" above could be dynamic, thereby eliminating
332		 * one more instance of the "number to vfs" mapping problem,
333		 * but "10" is the order as taken from sys/mount.h
334		 */
335		break;
336	case MODULE_CMD_FINI:
337		error = vfs_detach(&umapfs_vfsops);
338		if (error != 0)
339			break;
340		sysctl_teardown(&umapfs_sysctl_log);
341		break;
342	default:
343		error = ENOTTY;
344		break;
345	}
346
347	return (error);
348}
349