1/*
2 * Copyright (c) 1994, 1995 The Regents of the University of California.
3 * Copyright (c) 1994, 1995 Jan-Simon Pendry.
4 * All rights reserved.
5 *
6 * This code is derived from software donated to Berkeley by
7 * Jan-Simon Pendry.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * @(#)union_vfsops.c 8.20 (Berkeley) 5/20/95
| 1/*
2 * Copyright (c) 1994, 1995 The Regents of the University of California.
3 * Copyright (c) 1994, 1995 Jan-Simon Pendry.
4 * All rights reserved.
5 *
6 * This code is derived from software donated to Berkeley by
7 * Jan-Simon Pendry.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * @(#)union_vfsops.c 8.20 (Berkeley) 5/20/95
|
68
69/*
70 * Mount union filesystem
71 */
72static int
73union_mount(mp, path, data, ndp, td)
74 struct mount *mp;
75 char *path;
76 caddr_t data;
77 struct nameidata *ndp;
78 struct thread *td;
79{
80 int error = 0;
81 struct union_args args;
82 struct vnode *lowerrootvp = NULLVP;
83 struct vnode *upperrootvp = NULLVP;
84 struct union_mount *um = 0;
85 struct ucred *cred = 0;
86 char *cp = 0;
87 int len;
88 u_int size;
89
90 UDEBUG(("union_mount(mp = %p)\n", (void *)mp));
91
92 /*
93 * Disable clustered write, otherwise system becomes unstable.
94 */
95 mp->mnt_flag |= MNT_NOCLUSTERW;
96
97 /*
98 * Update is a no-op
99 */
100 if (mp->mnt_flag & MNT_UPDATE) {
101 /*
102 * Need to provide.
103 * 1. a way to convert between rdonly and rdwr mounts.
104 * 2. support for nfs exports.
105 */
106 error = EOPNOTSUPP;
107 goto bad;
108 }
109
110 /*
111 * Get argument
112 */
113 error = copyin(data, (caddr_t)&args, sizeof(struct union_args));
114 if (error)
115 goto bad;
116
117 /*
118 * Obtain lower vnode. Vnode is stored in mp->mnt_vnodecovered.
119 * We need to reference it but not lock it.
120 */
121
122 lowerrootvp = mp->mnt_vnodecovered;
123 VREF(lowerrootvp);
124
125#if 0
126 /*
127 * Unlock lower node to avoid deadlock.
128 */
129 if (lowerrootvp->v_op == union_vnodeop_p)
130 VOP_UNLOCK(lowerrootvp, 0, td);
131#endif
132
133 /*
134 * Obtain upper vnode by calling namei() on the path. The
135 * upperrootvp will be turned referenced but not locked.
136 */
137 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT,
138 UIO_USERSPACE, args.target, td);
139
140 error = namei(ndp);
141
142#if 0
143 if (lowerrootvp->v_op == union_vnodeop_p)
144 vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY, td);
145#endif
146 if (error)
147 goto bad;
148
149 NDFREE(ndp, NDF_ONLY_PNBUF);
150 upperrootvp = ndp->ni_vp;
151 vrele(ndp->ni_dvp);
152 ndp->ni_dvp = NULL;
153
154 UDEBUG(("mount_root UPPERVP %p locked = %d\n", upperrootvp,
155 VOP_ISLOCKED(upperrootvp, NULL)));
156
157 /*
158 * Check multi union mount to avoid `lock myself again' panic.
159 * Also require that it be a directory.
160 */
161 if (upperrootvp == VTOUNION(lowerrootvp)->un_uppervp) {
162#ifdef DIAGNOSTIC
163 printf("union_mount: multi union mount?\n");
164#endif
165 error = EDEADLK;
166 goto bad;
167 }
168
169 if (upperrootvp->v_type != VDIR) {
170 error = EINVAL;
171 goto bad;
172 }
173
174 /*
175 * Allocate our union_mount structure and populate the fields.
176 * The vnode references are stored in the union_mount as held,
177 * unlocked references. Depending on the _BELOW flag, the
178 * filesystems are viewed in a different order. In effect this
179 * is the same as providing a mount-under option to the mount
180 * syscall.
181 */
182
183 um = (struct union_mount *) malloc(sizeof(struct union_mount),
184 M_UNIONFSMNT, M_WAITOK | M_ZERO);
185
186 um->um_op = args.mntflags & UNMNT_OPMASK;
187
188 switch (um->um_op) {
189 case UNMNT_ABOVE:
190 um->um_lowervp = lowerrootvp;
191 um->um_uppervp = upperrootvp;
192 upperrootvp = NULL;
193 lowerrootvp = NULL;
194 break;
195
196 case UNMNT_BELOW:
197 um->um_lowervp = upperrootvp;
198 um->um_uppervp = lowerrootvp;
199 upperrootvp = NULL;
200 lowerrootvp = NULL;
201 break;
202
203 case UNMNT_REPLACE:
204 vrele(lowerrootvp);
205 lowerrootvp = NULL;
206 um->um_uppervp = upperrootvp;
207 um->um_lowervp = lowerrootvp;
208 upperrootvp = NULL;
209 break;
210
211 default:
212 error = EINVAL;
213 goto bad;
214 }
215
216 /*
217 * Unless the mount is readonly, ensure that the top layer
218 * supports whiteout operations
219 */
220 if ((mp->mnt_flag & MNT_RDONLY) == 0) {
221 error = VOP_WHITEOUT(um->um_uppervp, NULL, LOOKUP);
222 if (error)
223 goto bad;
224 }
225
226 um->um_cred = crhold(td->td_ucred);
227 FILEDESC_LOCK(td->td_proc->p_fd);
228 um->um_cmode = UN_DIRMODE &~ td->td_proc->p_fd->fd_cmask;
229 FILEDESC_UNLOCK(td->td_proc->p_fd);
230
231 /*
232 * Depending on what you think the MNT_LOCAL flag might mean,
233 * you may want the && to be || on the conditional below.
234 * At the moment it has been defined that the filesystem is
235 * only local if it is all local, ie the MNT_LOCAL flag implies
236 * that the entire namespace is local. If you think the MNT_LOCAL
237 * flag implies that some of the files might be stored locally
238 * then you will want to change the conditional.
239 */
240 if (um->um_op == UNMNT_ABOVE) {
241 if (((um->um_lowervp == NULLVP) ||
242 (um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) &&
243 (um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL))
244 mp->mnt_flag |= MNT_LOCAL;
245 }
246
247 /*
248 * Copy in the upper layer's RDONLY flag. This is for the benefit
249 * of lookup() which explicitly checks the flag, rather than asking
250 * the filesystem for its own opinion. This means, that an update
251 * mount of the underlying filesystem to go from rdonly to rdwr
252 * will leave the unioned view as read-only.
253 */
254 mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY);
255
256 mp->mnt_data = (qaddr_t) um;
257 vfs_getnewfsid(mp);
258
259 switch (um->um_op) {
260 case UNMNT_ABOVE:
261 cp = "<above>:";
262 break;
263 case UNMNT_BELOW:
264 cp = "<below>:";
265 break;
266 case UNMNT_REPLACE:
267 cp = "";
268 break;
269 }
270 len = strlen(cp);
271 bcopy(cp, mp->mnt_stat.f_mntfromname, len);
272
273 cp = mp->mnt_stat.f_mntfromname + len;
274 len = MNAMELEN - len;
275
276 (void) copyinstr(args.target, cp, len - 1, &size);
277 bzero(cp + size, len - size);
278
279 (void)union_statfs(mp, &mp->mnt_stat, td);
280
281 UDEBUG(("union_mount: from %s, on %s\n",
282 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname));
283 return (0);
284
285bad:
286 if (um) {
287 if (um->um_uppervp)
288 vrele(um->um_uppervp);
289 if (um->um_lowervp)
290 vrele(um->um_lowervp);
291 /* XXX other fields */
292 free(um, M_UNIONFSMNT);
293 }
294 if (cred)
295 crfree(cred);
296 if (upperrootvp)
297 vrele(upperrootvp);
298 if (lowerrootvp)
299 vrele(lowerrootvp);
300 return (error);
301}
302
303/*
304 * Free reference to union layer
305 */
306static int
307union_unmount(mp, mntflags, td)
308 struct mount *mp;
309 int mntflags;
310 struct thread *td;
311{
312 struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
313 int error;
314 int freeing;
315 int flags = 0;
316
317 UDEBUG(("union_unmount(mp = %p)\n", (void *)mp));
318
319 if (mntflags & MNT_FORCE)
320 flags |= FORCECLOSE;
321
322 /*
323 * Keep flushing vnodes from the mount list.
324 * This is needed because of the un_pvp held
325 * reference to the parent vnode.
326 * If more vnodes have been freed on a given pass,
327 * the try again. The loop will iterate at most
328 * (d) times, where (d) is the maximum tree depth
329 * in the filesystem.
330 */
331 for (freeing = 0; (error = vflush(mp, 0, flags)) != 0;) {
332 struct vnode *vp;
333 int n;
334
335 /* count #vnodes held on mount list */
336 mtx_lock(&mntvnode_mtx);
337 n = 0;
338 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes)
339 n++;
340 mtx_unlock(&mntvnode_mtx);
341
342 /* if this is unchanged then stop */
343 if (n == freeing)
344 break;
345
346 /* otherwise try once more time */
347 freeing = n;
348 }
349
350 /* If the most recent vflush failed, the filesystem is still busy. */
351 if (error)
352 return (error);
353
354 /*
355 * Discard references to upper and lower target vnodes.
356 */
357 if (um->um_lowervp)
358 vrele(um->um_lowervp);
359 vrele(um->um_uppervp);
360 crfree(um->um_cred);
361 /*
362 * Finally, throw away the union_mount structure
363 */
364 free(mp->mnt_data, M_UNIONFSMNT); /* XXX */
365 mp->mnt_data = 0;
366 return (0);
367}
368
369static int
370union_root(mp, vpp)
371 struct mount *mp;
372 struct vnode **vpp;
373{
374 struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
375 int error;
376
377 /*
378 * Supply an unlocked reference to um_uppervp and to um_lowervp. It
379 * is possible for um_uppervp to be locked without the associated
380 * root union_node being locked. We let union_allocvp() deal with
381 * it.
382 */
383 UDEBUG(("union_root UPPERVP %p locked = %d\n", um->um_uppervp,
384 VOP_ISLOCKED(um->um_uppervp, NULL)));
385
386 VREF(um->um_uppervp);
387 if (um->um_lowervp)
388 VREF(um->um_lowervp);
389
390 error = union_allocvp(vpp, mp, NULLVP, NULLVP, NULL,
391 um->um_uppervp, um->um_lowervp, 1);
392 UDEBUG(("error %d\n", error));
393 UDEBUG(("union_root2 UPPERVP %p locked = %d\n", um->um_uppervp,
394 VOP_ISLOCKED(um->um_uppervp, NULL)));
395
396 return (error);
397}
398
399static int
400union_statfs(mp, sbp, td)
401 struct mount *mp;
402 struct statfs *sbp;
403 struct thread *td;
404{
405 int error;
406 struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
407 struct statfs mstat;
408 int lbsize;
409
410 UDEBUG(("union_statfs(mp = %p, lvp = %p, uvp = %p)\n",
411 (void *)mp, (void *)um->um_lowervp, (void *)um->um_uppervp));
412
413 bzero(&mstat, sizeof(mstat));
414
415 if (um->um_lowervp) {
416 error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, td);
417 if (error)
418 return (error);
419 }
420
421 /* now copy across the "interesting" information and fake the rest */
422#if 0
423 sbp->f_type = mstat.f_type;
424 sbp->f_flags = mstat.f_flags;
425 sbp->f_bsize = mstat.f_bsize;
426 sbp->f_iosize = mstat.f_iosize;
427#endif
428 lbsize = mstat.f_bsize;
429 sbp->f_blocks = mstat.f_blocks;
430 sbp->f_bfree = mstat.f_bfree;
431 sbp->f_bavail = mstat.f_bavail;
432 sbp->f_files = mstat.f_files;
433 sbp->f_ffree = mstat.f_ffree;
434
435 error = VFS_STATFS(um->um_uppervp->v_mount, &mstat, td);
436 if (error)
437 return (error);
438
439 sbp->f_flags = mstat.f_flags;
440 sbp->f_bsize = mstat.f_bsize;
441 sbp->f_iosize = mstat.f_iosize;
442
443 /*
444 * if the lower and upper blocksizes differ, then frig the
445 * block counts so that the sizes reported by df make some
446 * kind of sense. none of this makes sense though.
447 */
448
449 if (mstat.f_bsize != lbsize)
450 sbp->f_blocks = ((off_t) sbp->f_blocks * lbsize) / mstat.f_bsize;
451
452 /*
453 * The "total" fields count total resources in all layers,
454 * the "free" fields count only those resources which are
455 * free in the upper layer (since only the upper layer
456 * is writeable).
457 */
458 sbp->f_blocks += mstat.f_blocks;
459 sbp->f_bfree = mstat.f_bfree;
460 sbp->f_bavail = mstat.f_bavail;
461 sbp->f_files += mstat.f_files;
462 sbp->f_ffree = mstat.f_ffree;
463
464 if (sbp != &mp->mnt_stat) {
465 sbp->f_type = mp->mnt_vfc->vfc_typenum;
466 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
467 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
468 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
469 }
470 return (0);
471}
472
473static struct vfsops union_vfsops = {
474 union_mount,
475 vfs_stdstart, /* underlying start already done */
476 union_unmount,
477 union_root,
478 vfs_stdquotactl,
479 union_statfs,
480 vfs_stdsync, /* XXX assumes no cached data on union level */
481 vfs_stdvget,
482 vfs_stdfhtovp,
483 vfs_stdcheckexp,
484 vfs_stdvptofh,
485 union_init,
486 vfs_stduninit,
487 vfs_stdextattrctl,
488};
489
490VFS_SET(union_vfsops, unionfs, VFCF_LOOPBACK);
| 68
69/*
70 * Mount union filesystem
71 */
72static int
73union_mount(mp, path, data, ndp, td)
74 struct mount *mp;
75 char *path;
76 caddr_t data;
77 struct nameidata *ndp;
78 struct thread *td;
79{
80 int error = 0;
81 struct union_args args;
82 struct vnode *lowerrootvp = NULLVP;
83 struct vnode *upperrootvp = NULLVP;
84 struct union_mount *um = 0;
85 struct ucred *cred = 0;
86 char *cp = 0;
87 int len;
88 u_int size;
89
90 UDEBUG(("union_mount(mp = %p)\n", (void *)mp));
91
92 /*
93 * Disable clustered write, otherwise system becomes unstable.
94 */
95 mp->mnt_flag |= MNT_NOCLUSTERW;
96
97 /*
98 * Update is a no-op
99 */
100 if (mp->mnt_flag & MNT_UPDATE) {
101 /*
102 * Need to provide.
103 * 1. a way to convert between rdonly and rdwr mounts.
104 * 2. support for nfs exports.
105 */
106 error = EOPNOTSUPP;
107 goto bad;
108 }
109
110 /*
111 * Get argument
112 */
113 error = copyin(data, (caddr_t)&args, sizeof(struct union_args));
114 if (error)
115 goto bad;
116
117 /*
118 * Obtain lower vnode. Vnode is stored in mp->mnt_vnodecovered.
119 * We need to reference it but not lock it.
120 */
121
122 lowerrootvp = mp->mnt_vnodecovered;
123 VREF(lowerrootvp);
124
125#if 0
126 /*
127 * Unlock lower node to avoid deadlock.
128 */
129 if (lowerrootvp->v_op == union_vnodeop_p)
130 VOP_UNLOCK(lowerrootvp, 0, td);
131#endif
132
133 /*
134 * Obtain upper vnode by calling namei() on the path. The
135 * upperrootvp will be turned referenced but not locked.
136 */
137 NDINIT(ndp, LOOKUP, FOLLOW|WANTPARENT,
138 UIO_USERSPACE, args.target, td);
139
140 error = namei(ndp);
141
142#if 0
143 if (lowerrootvp->v_op == union_vnodeop_p)
144 vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY, td);
145#endif
146 if (error)
147 goto bad;
148
149 NDFREE(ndp, NDF_ONLY_PNBUF);
150 upperrootvp = ndp->ni_vp;
151 vrele(ndp->ni_dvp);
152 ndp->ni_dvp = NULL;
153
154 UDEBUG(("mount_root UPPERVP %p locked = %d\n", upperrootvp,
155 VOP_ISLOCKED(upperrootvp, NULL)));
156
157 /*
158 * Check multi union mount to avoid `lock myself again' panic.
159 * Also require that it be a directory.
160 */
161 if (upperrootvp == VTOUNION(lowerrootvp)->un_uppervp) {
162#ifdef DIAGNOSTIC
163 printf("union_mount: multi union mount?\n");
164#endif
165 error = EDEADLK;
166 goto bad;
167 }
168
169 if (upperrootvp->v_type != VDIR) {
170 error = EINVAL;
171 goto bad;
172 }
173
174 /*
175 * Allocate our union_mount structure and populate the fields.
176 * The vnode references are stored in the union_mount as held,
177 * unlocked references. Depending on the _BELOW flag, the
178 * filesystems are viewed in a different order. In effect this
179 * is the same as providing a mount-under option to the mount
180 * syscall.
181 */
182
183 um = (struct union_mount *) malloc(sizeof(struct union_mount),
184 M_UNIONFSMNT, M_WAITOK | M_ZERO);
185
186 um->um_op = args.mntflags & UNMNT_OPMASK;
187
188 switch (um->um_op) {
189 case UNMNT_ABOVE:
190 um->um_lowervp = lowerrootvp;
191 um->um_uppervp = upperrootvp;
192 upperrootvp = NULL;
193 lowerrootvp = NULL;
194 break;
195
196 case UNMNT_BELOW:
197 um->um_lowervp = upperrootvp;
198 um->um_uppervp = lowerrootvp;
199 upperrootvp = NULL;
200 lowerrootvp = NULL;
201 break;
202
203 case UNMNT_REPLACE:
204 vrele(lowerrootvp);
205 lowerrootvp = NULL;
206 um->um_uppervp = upperrootvp;
207 um->um_lowervp = lowerrootvp;
208 upperrootvp = NULL;
209 break;
210
211 default:
212 error = EINVAL;
213 goto bad;
214 }
215
216 /*
217 * Unless the mount is readonly, ensure that the top layer
218 * supports whiteout operations
219 */
220 if ((mp->mnt_flag & MNT_RDONLY) == 0) {
221 error = VOP_WHITEOUT(um->um_uppervp, NULL, LOOKUP);
222 if (error)
223 goto bad;
224 }
225
226 um->um_cred = crhold(td->td_ucred);
227 FILEDESC_LOCK(td->td_proc->p_fd);
228 um->um_cmode = UN_DIRMODE &~ td->td_proc->p_fd->fd_cmask;
229 FILEDESC_UNLOCK(td->td_proc->p_fd);
230
231 /*
232 * Depending on what you think the MNT_LOCAL flag might mean,
233 * you may want the && to be || on the conditional below.
234 * At the moment it has been defined that the filesystem is
235 * only local if it is all local, ie the MNT_LOCAL flag implies
236 * that the entire namespace is local. If you think the MNT_LOCAL
237 * flag implies that some of the files might be stored locally
238 * then you will want to change the conditional.
239 */
240 if (um->um_op == UNMNT_ABOVE) {
241 if (((um->um_lowervp == NULLVP) ||
242 (um->um_lowervp->v_mount->mnt_flag & MNT_LOCAL)) &&
243 (um->um_uppervp->v_mount->mnt_flag & MNT_LOCAL))
244 mp->mnt_flag |= MNT_LOCAL;
245 }
246
247 /*
248 * Copy in the upper layer's RDONLY flag. This is for the benefit
249 * of lookup() which explicitly checks the flag, rather than asking
250 * the filesystem for its own opinion. This means, that an update
251 * mount of the underlying filesystem to go from rdonly to rdwr
252 * will leave the unioned view as read-only.
253 */
254 mp->mnt_flag |= (um->um_uppervp->v_mount->mnt_flag & MNT_RDONLY);
255
256 mp->mnt_data = (qaddr_t) um;
257 vfs_getnewfsid(mp);
258
259 switch (um->um_op) {
260 case UNMNT_ABOVE:
261 cp = "<above>:";
262 break;
263 case UNMNT_BELOW:
264 cp = "<below>:";
265 break;
266 case UNMNT_REPLACE:
267 cp = "";
268 break;
269 }
270 len = strlen(cp);
271 bcopy(cp, mp->mnt_stat.f_mntfromname, len);
272
273 cp = mp->mnt_stat.f_mntfromname + len;
274 len = MNAMELEN - len;
275
276 (void) copyinstr(args.target, cp, len - 1, &size);
277 bzero(cp + size, len - size);
278
279 (void)union_statfs(mp, &mp->mnt_stat, td);
280
281 UDEBUG(("union_mount: from %s, on %s\n",
282 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname));
283 return (0);
284
285bad:
286 if (um) {
287 if (um->um_uppervp)
288 vrele(um->um_uppervp);
289 if (um->um_lowervp)
290 vrele(um->um_lowervp);
291 /* XXX other fields */
292 free(um, M_UNIONFSMNT);
293 }
294 if (cred)
295 crfree(cred);
296 if (upperrootvp)
297 vrele(upperrootvp);
298 if (lowerrootvp)
299 vrele(lowerrootvp);
300 return (error);
301}
302
303/*
304 * Free reference to union layer
305 */
306static int
307union_unmount(mp, mntflags, td)
308 struct mount *mp;
309 int mntflags;
310 struct thread *td;
311{
312 struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
313 int error;
314 int freeing;
315 int flags = 0;
316
317 UDEBUG(("union_unmount(mp = %p)\n", (void *)mp));
318
319 if (mntflags & MNT_FORCE)
320 flags |= FORCECLOSE;
321
322 /*
323 * Keep flushing vnodes from the mount list.
324 * This is needed because of the un_pvp held
325 * reference to the parent vnode.
326 * If more vnodes have been freed on a given pass,
327 * the try again. The loop will iterate at most
328 * (d) times, where (d) is the maximum tree depth
329 * in the filesystem.
330 */
331 for (freeing = 0; (error = vflush(mp, 0, flags)) != 0;) {
332 struct vnode *vp;
333 int n;
334
335 /* count #vnodes held on mount list */
336 mtx_lock(&mntvnode_mtx);
337 n = 0;
338 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes)
339 n++;
340 mtx_unlock(&mntvnode_mtx);
341
342 /* if this is unchanged then stop */
343 if (n == freeing)
344 break;
345
346 /* otherwise try once more time */
347 freeing = n;
348 }
349
350 /* If the most recent vflush failed, the filesystem is still busy. */
351 if (error)
352 return (error);
353
354 /*
355 * Discard references to upper and lower target vnodes.
356 */
357 if (um->um_lowervp)
358 vrele(um->um_lowervp);
359 vrele(um->um_uppervp);
360 crfree(um->um_cred);
361 /*
362 * Finally, throw away the union_mount structure
363 */
364 free(mp->mnt_data, M_UNIONFSMNT); /* XXX */
365 mp->mnt_data = 0;
366 return (0);
367}
368
369static int
370union_root(mp, vpp)
371 struct mount *mp;
372 struct vnode **vpp;
373{
374 struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
375 int error;
376
377 /*
378 * Supply an unlocked reference to um_uppervp and to um_lowervp. It
379 * is possible for um_uppervp to be locked without the associated
380 * root union_node being locked. We let union_allocvp() deal with
381 * it.
382 */
383 UDEBUG(("union_root UPPERVP %p locked = %d\n", um->um_uppervp,
384 VOP_ISLOCKED(um->um_uppervp, NULL)));
385
386 VREF(um->um_uppervp);
387 if (um->um_lowervp)
388 VREF(um->um_lowervp);
389
390 error = union_allocvp(vpp, mp, NULLVP, NULLVP, NULL,
391 um->um_uppervp, um->um_lowervp, 1);
392 UDEBUG(("error %d\n", error));
393 UDEBUG(("union_root2 UPPERVP %p locked = %d\n", um->um_uppervp,
394 VOP_ISLOCKED(um->um_uppervp, NULL)));
395
396 return (error);
397}
398
399static int
400union_statfs(mp, sbp, td)
401 struct mount *mp;
402 struct statfs *sbp;
403 struct thread *td;
404{
405 int error;
406 struct union_mount *um = MOUNTTOUNIONMOUNT(mp);
407 struct statfs mstat;
408 int lbsize;
409
410 UDEBUG(("union_statfs(mp = %p, lvp = %p, uvp = %p)\n",
411 (void *)mp, (void *)um->um_lowervp, (void *)um->um_uppervp));
412
413 bzero(&mstat, sizeof(mstat));
414
415 if (um->um_lowervp) {
416 error = VFS_STATFS(um->um_lowervp->v_mount, &mstat, td);
417 if (error)
418 return (error);
419 }
420
421 /* now copy across the "interesting" information and fake the rest */
422#if 0
423 sbp->f_type = mstat.f_type;
424 sbp->f_flags = mstat.f_flags;
425 sbp->f_bsize = mstat.f_bsize;
426 sbp->f_iosize = mstat.f_iosize;
427#endif
428 lbsize = mstat.f_bsize;
429 sbp->f_blocks = mstat.f_blocks;
430 sbp->f_bfree = mstat.f_bfree;
431 sbp->f_bavail = mstat.f_bavail;
432 sbp->f_files = mstat.f_files;
433 sbp->f_ffree = mstat.f_ffree;
434
435 error = VFS_STATFS(um->um_uppervp->v_mount, &mstat, td);
436 if (error)
437 return (error);
438
439 sbp->f_flags = mstat.f_flags;
440 sbp->f_bsize = mstat.f_bsize;
441 sbp->f_iosize = mstat.f_iosize;
442
443 /*
444 * if the lower and upper blocksizes differ, then frig the
445 * block counts so that the sizes reported by df make some
446 * kind of sense. none of this makes sense though.
447 */
448
449 if (mstat.f_bsize != lbsize)
450 sbp->f_blocks = ((off_t) sbp->f_blocks * lbsize) / mstat.f_bsize;
451
452 /*
453 * The "total" fields count total resources in all layers,
454 * the "free" fields count only those resources which are
455 * free in the upper layer (since only the upper layer
456 * is writeable).
457 */
458 sbp->f_blocks += mstat.f_blocks;
459 sbp->f_bfree = mstat.f_bfree;
460 sbp->f_bavail = mstat.f_bavail;
461 sbp->f_files += mstat.f_files;
462 sbp->f_ffree = mstat.f_ffree;
463
464 if (sbp != &mp->mnt_stat) {
465 sbp->f_type = mp->mnt_vfc->vfc_typenum;
466 bcopy(&mp->mnt_stat.f_fsid, &sbp->f_fsid, sizeof(sbp->f_fsid));
467 bcopy(mp->mnt_stat.f_mntonname, sbp->f_mntonname, MNAMELEN);
468 bcopy(mp->mnt_stat.f_mntfromname, sbp->f_mntfromname, MNAMELEN);
469 }
470 return (0);
471}
472
473static struct vfsops union_vfsops = {
474 union_mount,
475 vfs_stdstart, /* underlying start already done */
476 union_unmount,
477 union_root,
478 vfs_stdquotactl,
479 union_statfs,
480 vfs_stdsync, /* XXX assumes no cached data on union level */
481 vfs_stdvget,
482 vfs_stdfhtovp,
483 vfs_stdcheckexp,
484 vfs_stdvptofh,
485 union_init,
486 vfs_stduninit,
487 vfs_stdextattrctl,
488};
489
490VFS_SET(union_vfsops, unionfs, VFCF_LOOPBACK);
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