1 /*-
2 * Copyright (c) 1992, 1993, 1995
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 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * @(#)null_vfsops.c 8.2 (Berkeley) 1/21/94
33 *
34 * @(#)lofs_vfsops.c 1.2 (Berkeley) 6/18/92
35 * $FreeBSD: releng/6.0/sys/fs/nullfs/null_vfsops.c 151669 2005-10-25 20:33:59Z kris $
36 */
37
38 /*
39 * Null Layer
40 * (See null_vnops.c for a description of what this does.)
41 */
42
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/kdb.h>
46 #include <sys/kernel.h>
47 #include <sys/lock.h>
48 #include <sys/malloc.h>
49 #include <sys/mount.h>
50 #include <sys/namei.h>
51 #include <sys/proc.h>
52 #include <sys/vnode.h>
53
54 #include <fs/nullfs/null.h>
55
56 static MALLOC_DEFINE(M_NULLFSMNT, "NULLFS mount", "NULLFS mount structure");
57
58 static vfs_fhtovp_t nullfs_fhtovp;
59 static vfs_checkexp_t nullfs_checkexp;
60 static vfs_mount_t nullfs_mount;
61 static vfs_quotactl_t nullfs_quotactl;
62 static vfs_root_t nullfs_root;
63 static vfs_sync_t nullfs_sync;
64 static vfs_statfs_t nullfs_statfs;
65 static vfs_unmount_t nullfs_unmount;
66 static vfs_vget_t nullfs_vget;
67 static vfs_vptofh_t nullfs_vptofh;
68 static vfs_extattrctl_t nullfs_extattrctl;
69
70 /*
71 * Mount null layer
72 */
73 static int
74 nullfs_mount(struct mount *mp, struct thread *td)
75 {
76 int error = 0;
77 struct vnode *lowerrootvp, *vp;
78 struct vnode *nullm_rootvp;
79 struct null_mount *xmp;
80 char *target;
81 int isvnunlocked = 0, len;
82 struct nameidata nd, *ndp = &nd;
83
84 NULLFSDEBUG("nullfs_mount(mp = %p)\n", (void *)mp);
85
86 if (mp->mnt_flag & MNT_ROOTFS)
87 return (EOPNOTSUPP);
88 /*
89 * Update is a no-op
90 */
91 if (mp->mnt_flag & MNT_UPDATE) {
92 return (EOPNOTSUPP);
93 /* return VFS_MOUNT(MOUNTTONULLMOUNT(mp)->nullm_vfs, path, data, ndp, td);*/
94 }
95
96 /*
97 * Get argument
98 */
99 error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len);
100 if (error || target[len - 1] != '\0')
101 return (EINVAL);
102
103 /*
104 * Unlock lower node to avoid deadlock.
105 * (XXX) VOP_ISLOCKED is needed?
106 */
107 if ((mp->mnt_vnodecovered->v_op == &null_vnodeops) &&
108 VOP_ISLOCKED(mp->mnt_vnodecovered, NULL)) {
109 VOP_UNLOCK(mp->mnt_vnodecovered, 0, td);
110 isvnunlocked = 1;
111 }
112 /*
113 * Find lower node
114 */
115 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT|LOCKLEAF,
116 UIO_SYSSPACE, target, td);
117 error = namei(ndp);
118 /*
119 * Re-lock vnode.
120 */
121 if (isvnunlocked && !VOP_ISLOCKED(mp->mnt_vnodecovered, NULL))
122 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY, td);
123
124 if (error)
125 return (error);
126 NDFREE(ndp, NDF_ONLY_PNBUF);
127
128 /*
129 * Sanity check on lower vnode
130 */
131 lowerrootvp = ndp->ni_vp;
132
133 vrele(ndp->ni_dvp);
134 ndp->ni_dvp = NULLVP;
135
136 /*
137 * Check multi null mount to avoid `lock against myself' panic.
138 */
139 if (lowerrootvp == VTONULL(mp->mnt_vnodecovered)->null_lowervp) {
140 NULLFSDEBUG("nullfs_mount: multi null mount?\n");
141 vput(lowerrootvp);
142 return (EDEADLK);
143 }
144
145 xmp = (struct null_mount *) malloc(sizeof(struct null_mount),
146 M_NULLFSMNT, M_WAITOK); /* XXX */
147
148 /*
149 * Save reference to underlying FS
150 */
151 xmp->nullm_vfs = lowerrootvp->v_mount;
152
153 /*
154 * Save reference. Each mount also holds
155 * a reference on the root vnode.
156 */
157 error = null_nodeget(mp, lowerrootvp, &vp);
158 /*
159 * Make sure the node alias worked
160 */
161 if (error) {
162 VOP_UNLOCK(vp, 0, td);
163 vrele(lowerrootvp);
164 free(xmp, M_NULLFSMNT); /* XXX */
165 return (error);
166 }
167
168 /*
169 * Keep a held reference to the root vnode.
170 * It is vrele'd in nullfs_unmount.
171 */
172 nullm_rootvp = vp;
173 nullm_rootvp->v_vflag |= VV_ROOT;
174 xmp->nullm_rootvp = nullm_rootvp;
175
176 /*
177 * Unlock the node (either the lower or the alias)
178 */
179 VOP_UNLOCK(vp, 0, td);
180
181 if (NULLVPTOLOWERVP(nullm_rootvp)->v_mount->mnt_flag & MNT_LOCAL)
182 mp->mnt_flag |= MNT_LOCAL;
183 mp->mnt_kern_flag |= lowerrootvp->v_mount->mnt_kern_flag | MNTK_MPSAFE;
184 mp->mnt_data = (qaddr_t) xmp;
185 vfs_getnewfsid(mp);
186
187 vfs_mountedfrom(mp, target);
188
189 NULLFSDEBUG("nullfs_mount: lower %s, alias at %s\n",
190 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
191 return (0);
192 }
193
194 /*
195 * Free reference to null layer
196 */
197 static int
198 nullfs_unmount(mp, mntflags, td)
199 struct mount *mp;
200 int mntflags;
201 struct thread *td;
202 {
203 void *mntdata;
204 int error;
205 int flags = 0;
206
207 NULLFSDEBUG("nullfs_unmount: mp = %p\n", (void *)mp);
208
209 if (mntflags & MNT_FORCE)
210 flags |= FORCECLOSE;
211
212 /* There is 1 extra root vnode reference (nullm_rootvp). */
213 error = vflush(mp, 1, flags, td);
214 if (error)
215 return (error);
216
217 /*
218 * Finally, throw away the null_mount structure
219 */
220 mntdata = mp->mnt_data;
221 mp->mnt_data = 0;
222 free(mntdata, M_NULLFSMNT);
223 return 0;
224 }
225
226 static int
227 nullfs_root(mp, flags, vpp, td)
228 struct mount *mp;
229 int flags;
230 struct vnode **vpp;
231 struct thread *td;
232 {
233 struct vnode *vp;
234
235 NULLFSDEBUG("nullfs_root(mp = %p, vp = %p->%p)\n", (void *)mp,
236 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
237 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
238
239 /*
240 * Return locked reference to root.
241 */
242 vp = MOUNTTONULLMOUNT(mp)->nullm_rootvp;
243 VREF(vp);
244
245 #ifdef NULLFS_DEBUG
246 if (VOP_ISLOCKED(vp, NULL)) {
247 kdb_enter("root vnode is locked.\n");
248 vrele(vp);
249 return (EDEADLK);
250 }
251 #endif
252 vn_lock(vp, flags | LK_RETRY, td);
253 *vpp = vp;
254 return 0;
255 }
256
257 static int
258 nullfs_quotactl(mp, cmd, uid, arg, td)
259 struct mount *mp;
260 int cmd;
261 uid_t uid;
262 caddr_t arg;
263 struct thread *td;
264 {
265 return VFS_QUOTACTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, uid, arg, td);
266 }
267
268 static int
269 nullfs_statfs(mp, sbp, td)
270 struct mount *mp;
271 struct statfs *sbp;
272 struct thread *td;
273 {
274 int error;
275 struct statfs mstat;
276
277 NULLFSDEBUG("nullfs_statfs(mp = %p, vp = %p->%p)\n", (void *)mp,
278 (void *)MOUNTTONULLMOUNT(mp)->nullm_rootvp,
279 (void *)NULLVPTOLOWERVP(MOUNTTONULLMOUNT(mp)->nullm_rootvp));
280
281 bzero(&mstat, sizeof(mstat));
282
283 error = VFS_STATFS(MOUNTTONULLMOUNT(mp)->nullm_vfs, &mstat, td);
284 if (error)
285 return (error);
286
287 /* now copy across the "interesting" information and fake the rest */
288 sbp->f_type = mstat.f_type;
289 sbp->f_flags = mstat.f_flags;
290 sbp->f_bsize = mstat.f_bsize;
291 sbp->f_iosize = mstat.f_iosize;
292 sbp->f_blocks = mstat.f_blocks;
293 sbp->f_bfree = mstat.f_bfree;
294 sbp->f_bavail = mstat.f_bavail;
295 sbp->f_files = mstat.f_files;
296 sbp->f_ffree = mstat.f_ffree;
297 return (0);
298 }
299
300 static int
301 nullfs_sync(mp, waitfor, td)
302 struct mount *mp;
303 int waitfor;
304 struct thread *td;
305 {
306 /*
307 * XXX - Assumes no data cached at null layer.
308 */
309 return (0);
310 }
311
312 static int
313 nullfs_vget(mp, ino, flags, vpp)
314 struct mount *mp;
315 ino_t ino;
316 int flags;
317 struct vnode **vpp;
318 {
319 int error;
320 error = VFS_VGET(MOUNTTONULLMOUNT(mp)->nullm_vfs, ino, flags, vpp);
321 if (error)
322 return (error);
323
324 return (null_nodeget(mp, *vpp, vpp));
325 }
326
327 static int
328 nullfs_fhtovp(mp, fidp, vpp)
329 struct mount *mp;
330 struct fid *fidp;
331 struct vnode **vpp;
332 {
333 int error;
334 error = VFS_FHTOVP(MOUNTTONULLMOUNT(mp)->nullm_vfs, fidp, vpp);
335 if (error)
336 return (error);
337
338 return (null_nodeget(mp, *vpp, vpp));
339 }
340
341 static int
342 nullfs_checkexp(mp, nam, extflagsp, credanonp)
343 struct mount *mp;
344 struct sockaddr *nam;
345 int *extflagsp;
346 struct ucred **credanonp;
347 {
348
349 return VFS_CHECKEXP(MOUNTTONULLMOUNT(mp)->nullm_vfs, nam,
350 extflagsp, credanonp);
351 }
352
353 static int
354 nullfs_vptofh(vp, fhp)
355 struct vnode *vp;
356 struct fid *fhp;
357 {
358 struct vnode *lvp;
359
360 lvp = NULLVPTOLOWERVP(vp);
361 return VFS_VPTOFH(lvp, fhp);
362 }
363
364 static int
365 nullfs_extattrctl(mp, cmd, filename_vp, namespace, attrname, td)
366 struct mount *mp;
367 int cmd;
368 struct vnode *filename_vp;
369 int namespace;
370 const char *attrname;
371 struct thread *td;
372 {
373 return VFS_EXTATTRCTL(MOUNTTONULLMOUNT(mp)->nullm_vfs, cmd, filename_vp,
374 namespace, attrname, td);
375 }
376
377
378 static struct vfsops null_vfsops = {
379 .vfs_checkexp = nullfs_checkexp,
380 .vfs_extattrctl = nullfs_extattrctl,
381 .vfs_fhtovp = nullfs_fhtovp,
382 .vfs_init = nullfs_init,
383 .vfs_mount = nullfs_mount,
384 .vfs_quotactl = nullfs_quotactl,
385 .vfs_root = nullfs_root,
386 .vfs_statfs = nullfs_statfs,
387 .vfs_sync = nullfs_sync,
388 .vfs_uninit = nullfs_uninit,
389 .vfs_unmount = nullfs_unmount,
390 .vfs_vget = nullfs_vget,
391 .vfs_vptofh = nullfs_vptofh,
392 };
393
394 VFS_SET(null_vfsops, nullfs, VFCF_LOOPBACK);
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