1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1994, 1995 The Regents of the University of California.
5 * Copyright (c) 1994, 1995 Jan-Simon Pendry.
6 * Copyright (c) 2005, 2006, 2012 Masanori Ozawa <ozawa@ongs.co.jp>, ONGS Inc.
7 * Copyright (c) 2006, 2012 Daichi Goto <daichi@freebsd.org>
8 * All rights reserved.
9 *
10 * This code is derived from software donated to Berkeley by
11 * Jan-Simon Pendry.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution.
21 * 3. 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
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/kdb.h>
41 #include <sys/fcntl.h>
42 #include <sys/kernel.h>
43 #include <sys/lock.h>
44 #include <sys/malloc.h>
45 #include <sys/mount.h>
46 #include <sys/namei.h>
47 #include <sys/proc.h>
48 #include <sys/vnode.h>
49 #include <sys/stat.h>
50
51 #include <fs/unionfs/union.h>
52
53 static MALLOC_DEFINE(M_UNIONFSMNT, "UNIONFS mount", "UNIONFS mount structure");
54
55 static vfs_fhtovp_t unionfs_fhtovp;
56 static vfs_checkexp_t unionfs_checkexp;
57 static vfs_mount_t unionfs_domount;
58 static vfs_quotactl_t unionfs_quotactl;
59 static vfs_root_t unionfs_root;
60 static vfs_sync_t unionfs_sync;
61 static vfs_statfs_t unionfs_statfs;
62 static vfs_unmount_t unionfs_unmount;
63 static vfs_vget_t unionfs_vget;
64 static vfs_extattrctl_t unionfs_extattrctl;
65
66 static struct vfsops unionfs_vfsops;
67
68 /*
69 * Mount unionfs layer.
70 */
71 static int
unionfs_domount(struct mount * mp)72 unionfs_domount(struct mount *mp)
73 {
74 struct vnode *lowerrootvp;
75 struct vnode *upperrootvp;
76 struct vnode *lvp1;
77 struct vnode *lvp2;
78 struct unionfs_mount *ump;
79 char *target;
80 char *tmp;
81 char *ep;
82 struct nameidata nd, *ndp;
83 struct vattr va;
84 unionfs_copymode copymode;
85 unionfs_whitemode whitemode;
86 int below;
87 int error;
88 int len;
89 uid_t uid;
90 gid_t gid;
91 u_short udir;
92 u_short ufile;
93
94 UNIONFSDEBUG("unionfs_mount(mp = %p)\n", mp);
95
96 error = 0;
97 below = 0;
98 uid = 0;
99 gid = 0;
100 udir = 0;
101 ufile = 0;
102 copymode = UNIONFS_TRANSPARENT; /* default */
103 whitemode = UNIONFS_WHITE_ALWAYS;
104 ndp = &nd;
105
106 if (mp->mnt_flag & MNT_ROOTFS) {
107 vfs_mount_error(mp, "Cannot union mount root filesystem");
108 return (EOPNOTSUPP);
109 }
110
111 /*
112 * Update is a no operation.
113 */
114 if (mp->mnt_flag & MNT_UPDATE) {
115 vfs_mount_error(mp, "unionfs does not support mount update");
116 return (EOPNOTSUPP);
117 }
118
119 /*
120 * Get argument
121 */
122 error = vfs_getopt(mp->mnt_optnew, "target", (void **)&target, &len);
123 if (error)
124 error = vfs_getopt(mp->mnt_optnew, "from", (void **)&target,
125 &len);
126 if (error || target[len - 1] != '\0') {
127 vfs_mount_error(mp, "Invalid target");
128 return (EINVAL);
129 }
130 if (vfs_getopt(mp->mnt_optnew, "below", NULL, NULL) == 0)
131 below = 1;
132 if (vfs_getopt(mp->mnt_optnew, "udir", (void **)&tmp, NULL) == 0) {
133 if (tmp != NULL)
134 udir = (mode_t)strtol(tmp, &ep, 8);
135 if (tmp == NULL || *ep) {
136 vfs_mount_error(mp, "Invalid udir");
137 return (EINVAL);
138 }
139 udir &= S_IRWXU | S_IRWXG | S_IRWXO;
140 }
141 if (vfs_getopt(mp->mnt_optnew, "ufile", (void **)&tmp, NULL) == 0) {
142 if (tmp != NULL)
143 ufile = (mode_t)strtol(tmp, &ep, 8);
144 if (tmp == NULL || *ep) {
145 vfs_mount_error(mp, "Invalid ufile");
146 return (EINVAL);
147 }
148 ufile &= S_IRWXU | S_IRWXG | S_IRWXO;
149 }
150 /* check umask, uid and gid */
151 if (udir == 0 && ufile != 0)
152 udir = ufile;
153 if (ufile == 0 && udir != 0)
154 ufile = udir;
155
156 vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
157 error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred);
158 if (!error) {
159 if (udir == 0)
160 udir = va.va_mode;
161 if (ufile == 0)
162 ufile = va.va_mode;
163 uid = va.va_uid;
164 gid = va.va_gid;
165 }
166 VOP_UNLOCK(mp->mnt_vnodecovered);
167 if (error)
168 return (error);
169
170 if (mp->mnt_cred->cr_ruid == 0) { /* root only */
171 if (vfs_getopt(mp->mnt_optnew, "uid", (void **)&tmp,
172 NULL) == 0) {
173 if (tmp != NULL)
174 uid = (uid_t)strtol(tmp, &ep, 10);
175 if (tmp == NULL || *ep) {
176 vfs_mount_error(mp, "Invalid uid");
177 return (EINVAL);
178 }
179 }
180 if (vfs_getopt(mp->mnt_optnew, "gid", (void **)&tmp,
181 NULL) == 0) {
182 if (tmp != NULL)
183 gid = (gid_t)strtol(tmp, &ep, 10);
184 if (tmp == NULL || *ep) {
185 vfs_mount_error(mp, "Invalid gid");
186 return (EINVAL);
187 }
188 }
189 if (vfs_getopt(mp->mnt_optnew, "copymode", (void **)&tmp,
190 NULL) == 0) {
191 if (tmp == NULL) {
192 vfs_mount_error(mp, "Invalid copymode");
193 return (EINVAL);
194 } else if (strcasecmp(tmp, "traditional") == 0)
195 copymode = UNIONFS_TRADITIONAL;
196 else if (strcasecmp(tmp, "transparent") == 0)
197 copymode = UNIONFS_TRANSPARENT;
198 else if (strcasecmp(tmp, "masquerade") == 0)
199 copymode = UNIONFS_MASQUERADE;
200 else {
201 vfs_mount_error(mp, "Invalid copymode");
202 return (EINVAL);
203 }
204 }
205 if (vfs_getopt(mp->mnt_optnew, "whiteout", (void **)&tmp,
206 NULL) == 0) {
207 if (tmp == NULL) {
208 vfs_mount_error(mp, "Invalid whiteout mode");
209 return (EINVAL);
210 } else if (strcasecmp(tmp, "always") == 0)
211 whitemode = UNIONFS_WHITE_ALWAYS;
212 else if (strcasecmp(tmp, "whenneeded") == 0)
213 whitemode = UNIONFS_WHITE_WHENNEEDED;
214 else {
215 vfs_mount_error(mp, "Invalid whiteout mode");
216 return (EINVAL);
217 }
218 }
219 }
220 /* If copymode is UNIONFS_TRADITIONAL, uid/gid is mounted user. */
221 if (copymode == UNIONFS_TRADITIONAL) {
222 uid = mp->mnt_cred->cr_ruid;
223 gid = mp->mnt_cred->cr_rgid;
224 }
225
226 UNIONFSDEBUG("unionfs_mount: uid=%d, gid=%d\n", uid, gid);
227 UNIONFSDEBUG("unionfs_mount: udir=0%03o, ufile=0%03o\n", udir, ufile);
228 UNIONFSDEBUG("unionfs_mount: copymode=%d\n", copymode);
229
230 /*
231 * Find upper node
232 */
233 NDINIT(ndp, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, target);
234 if ((error = namei(ndp)))
235 return (error);
236
237 NDFREE_PNBUF(ndp);
238
239 /* get root vnodes */
240 lowerrootvp = mp->mnt_vnodecovered;
241 upperrootvp = ndp->ni_vp;
242 KASSERT(lowerrootvp != NULL, ("%s: NULL lower root vp", __func__));
243 KASSERT(upperrootvp != NULL, ("%s: NULL upper root vp", __func__));
244
245 /* create unionfs_mount */
246 ump = malloc(sizeof(struct unionfs_mount), M_UNIONFSMNT,
247 M_WAITOK | M_ZERO);
248
249 /*
250 * Save reference
251 */
252 if (below) {
253 VOP_UNLOCK(upperrootvp);
254 vn_lock(lowerrootvp, LK_EXCLUSIVE | LK_RETRY);
255 ump->um_lowervp = upperrootvp;
256 ump->um_uppervp = lowerrootvp;
257 } else {
258 ump->um_lowervp = lowerrootvp;
259 ump->um_uppervp = upperrootvp;
260 }
261 ump->um_rootvp = NULL;
262 ump->um_uid = uid;
263 ump->um_gid = gid;
264 ump->um_udir = udir;
265 ump->um_ufile = ufile;
266 ump->um_copymode = copymode;
267 ump->um_whitemode = whitemode;
268
269 mp->mnt_data = ump;
270
271 /*
272 * Copy upper layer's RDONLY flag.
273 */
274 mp->mnt_flag |= ump->um_uppervp->v_mount->mnt_flag & MNT_RDONLY;
275
276 /*
277 * Unlock the node
278 */
279 VOP_UNLOCK(ump->um_uppervp);
280
281 /*
282 * Detect common cases in which constructing a unionfs hierarchy
283 * would produce deadlock (or failed locking assertions) upon
284 * use of the resulting unionfs vnodes. This typically happens
285 * when the requested upper and lower filesytems (which themselves
286 * may be unionfs instances and/or nullfs aliases) end up resolving
287 * to the same base-layer files. Note that this is not meant to be
288 * an exhaustive check of all possible deadlock-producing scenarios.
289 */
290 lvp1 = lvp2 = NULL;
291 VOP_GETLOWVNODE(ump->um_lowervp, &lvp1, FREAD);
292 VOP_GETLOWVNODE(ump->um_uppervp, &lvp2, FREAD);
293 if (lvp1 != NULL && lvp1 == lvp2)
294 error = EDEADLK;
295 if (lvp1 != NULL)
296 vrele(lvp1);
297 if (lvp2 != NULL)
298 vrele(lvp2);
299
300 /*
301 * Get the unionfs root vnode.
302 */
303 if (error == 0) {
304 error = unionfs_nodeget(mp, ump->um_uppervp, ump->um_lowervp,
305 NULL, &(ump->um_rootvp), NULL);
306 }
307 if (error != 0) {
308 vrele(upperrootvp);
309 free(ump, M_UNIONFSMNT);
310 mp->mnt_data = NULL;
311 return (error);
312 }
313 KASSERT(ump->um_rootvp != NULL, ("rootvp cannot be NULL"));
314 KASSERT((ump->um_rootvp->v_vflag & VV_ROOT) != 0,
315 ("%s: rootvp without VV_ROOT", __func__));
316
317 /*
318 * Do not release the namei() reference on upperrootvp until after
319 * we attempt to register the upper mounts. A concurrent unmount
320 * of the upper or lower FS may have caused unionfs_nodeget() to
321 * create a unionfs node with a NULL upper or lower vp and with
322 * no reference held on upperrootvp or lowerrootvp.
323 * vfs_register_upper() should subsequently fail, which is what
324 * we want, but we must ensure neither underlying vnode can be
325 * reused until that happens. We assume the caller holds a reference
326 * to lowerrootvp as it is the mount's covered vnode.
327 */
328 ump->um_lowermp = vfs_register_upper_from_vp(ump->um_lowervp, mp,
329 &ump->um_lower_link);
330 ump->um_uppermp = vfs_register_upper_from_vp(ump->um_uppervp, mp,
331 &ump->um_upper_link);
332
333 vrele(upperrootvp);
334
335 if (ump->um_lowermp == NULL || ump->um_uppermp == NULL) {
336 if (ump->um_lowermp != NULL)
337 vfs_unregister_upper(ump->um_lowermp, &ump->um_lower_link);
338 if (ump->um_uppermp != NULL)
339 vfs_unregister_upper(ump->um_uppermp, &ump->um_upper_link);
340 vflush(mp, 1, FORCECLOSE, curthread);
341 free(ump, M_UNIONFSMNT);
342 mp->mnt_data = NULL;
343 return (ENOENT);
344 }
345
346 /*
347 * Specify that the covered vnode lock should remain held while
348 * lookup() performs the cross-mount walk. This prevents a lock-order
349 * reversal between the covered vnode lock (which is also locked by
350 * unionfs_lock()) and the mountpoint's busy count. Without this,
351 * unmount will lock the covered vnode lock (directly through the
352 * covered vnode) and wait for the busy count to drain, while a
353 * concurrent lookup will increment the busy count and then may lock
354 * the covered vnode lock (indirectly through unionfs_lock()).
355 *
356 * Note that this is only needed for the 'below' case in which the
357 * upper vnode is also the covered vnode, because unionfs_lock()
358 * only locks the upper vnode as long as both lower and upper vnodes
359 * are present (which they will always be for the unionfs mount root).
360 */
361 if (below) {
362 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY | LK_CANRECURSE);
363 mp->mnt_vnodecovered->v_vflag |= VV_CROSSLOCK;
364 VOP_UNLOCK(mp->mnt_vnodecovered);
365 }
366
367 MNT_ILOCK(mp);
368 if ((ump->um_lowermp->mnt_flag & MNT_LOCAL) != 0 &&
369 (ump->um_uppermp->mnt_flag & MNT_LOCAL) != 0)
370 mp->mnt_flag |= MNT_LOCAL;
371 mp->mnt_kern_flag |= MNTK_NOMSYNC | MNTK_UNIONFS |
372 (ump->um_uppermp->mnt_kern_flag & MNTK_SHARED_WRITES);
373 MNT_IUNLOCK(mp);
374
375 /*
376 * Get new fsid
377 */
378 vfs_getnewfsid(mp);
379
380 snprintf(mp->mnt_stat.f_mntfromname, MNAMELEN, "<%s>:%s",
381 below ? "below" : "above", target);
382
383 UNIONFSDEBUG("unionfs_mount: from %s, on %s\n",
384 mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntonname);
385
386 return (0);
387 }
388
389 /*
390 * Free reference to unionfs layer
391 */
392 static int
unionfs_unmount(struct mount * mp,int mntflags)393 unionfs_unmount(struct mount *mp, int mntflags)
394 {
395 struct unionfs_mount *ump;
396 int error;
397 int num;
398 int freeing;
399 int flags;
400
401 UNIONFSDEBUG("unionfs_unmount: mp = %p\n", mp);
402
403 ump = MOUNTTOUNIONFSMOUNT(mp);
404 flags = 0;
405
406 if (mntflags & MNT_FORCE)
407 flags |= FORCECLOSE;
408
409 /* vflush (no need to call vrele) */
410 for (freeing = 0; (error = vflush(mp, 1, flags, curthread)) != 0;) {
411 num = mp->mnt_nvnodelistsize;
412 if (num == freeing)
413 break;
414 freeing = num;
415 }
416
417 if (error)
418 return (error);
419
420 vn_lock(mp->mnt_vnodecovered, LK_EXCLUSIVE | LK_RETRY | LK_CANRECURSE);
421 mp->mnt_vnodecovered->v_vflag &= ~VV_CROSSLOCK;
422 VOP_UNLOCK(mp->mnt_vnodecovered);
423 vfs_unregister_upper(ump->um_lowermp, &ump->um_lower_link);
424 vfs_unregister_upper(ump->um_uppermp, &ump->um_upper_link);
425 free(ump, M_UNIONFSMNT);
426 mp->mnt_data = NULL;
427
428 return (0);
429 }
430
431 static int
unionfs_root(struct mount * mp,int flags,struct vnode ** vpp)432 unionfs_root(struct mount *mp, int flags, struct vnode **vpp)
433 {
434 struct unionfs_mount *ump;
435 struct vnode *vp;
436
437 ump = MOUNTTOUNIONFSMOUNT(mp);
438 vp = ump->um_rootvp;
439
440 UNIONFSDEBUG("unionfs_root: rootvp=%p locked=%x\n",
441 vp, VOP_ISLOCKED(vp));
442
443 vref(vp);
444 if (flags & LK_TYPE_MASK)
445 vn_lock(vp, flags);
446
447 *vpp = vp;
448
449 return (0);
450 }
451
452 static int
unionfs_quotactl(struct mount * mp,int cmd,uid_t uid,void * arg,bool * mp_busy)453 unionfs_quotactl(struct mount *mp, int cmd, uid_t uid, void *arg,
454 bool *mp_busy)
455 {
456 struct mount *uppermp;
457 struct unionfs_mount *ump;
458 int error;
459 bool unbusy;
460
461 ump = MOUNTTOUNIONFSMOUNT(mp);
462 /*
463 * Issue a volatile load of um_uppermp here, as the mount may be
464 * torn down after we call vfs_unbusy().
465 */
466 uppermp = atomic_load_ptr(&ump->um_uppermp);
467 KASSERT(*mp_busy == true, ("upper mount not busy"));
468 /*
469 * See comment in sys_quotactl() for an explanation of why the
470 * lower mount needs to be busied by the caller of VFS_QUOTACTL()
471 * but may be unbusied by the implementation. We must unbusy
472 * the upper mount for the same reason; otherwise a namei lookup
473 * issued by the VFS_QUOTACTL() implementation could traverse the
474 * upper mount and deadlock.
475 */
476 vfs_unbusy(mp);
477 *mp_busy = false;
478 unbusy = true;
479 error = vfs_busy(uppermp, 0);
480 /*
481 * Writing is always performed to upper vnode.
482 */
483 if (error == 0)
484 error = VFS_QUOTACTL(uppermp, cmd, uid, arg, &unbusy);
485 if (unbusy)
486 vfs_unbusy(uppermp);
487
488 return (error);
489 }
490
491 static int
unionfs_statfs(struct mount * mp,struct statfs * sbp)492 unionfs_statfs(struct mount *mp, struct statfs *sbp)
493 {
494 struct unionfs_mount *ump;
495 struct statfs *mstat;
496 uint64_t lbsize;
497 int error;
498
499 ump = MOUNTTOUNIONFSMOUNT(mp);
500
501 UNIONFSDEBUG("unionfs_statfs(mp = %p, lvp = %p, uvp = %p)\n",
502 mp, ump->um_lowervp, ump->um_uppervp);
503
504 mstat = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK | M_ZERO);
505
506 error = VFS_STATFS(ump->um_lowermp, mstat);
507 if (error) {
508 free(mstat, M_STATFS);
509 return (error);
510 }
511
512 /* now copy across the "interesting" information and fake the rest */
513 sbp->f_blocks = mstat->f_blocks;
514 sbp->f_files = mstat->f_files;
515
516 lbsize = mstat->f_bsize;
517
518 error = VFS_STATFS(ump->um_uppermp, mstat);
519 if (error) {
520 free(mstat, M_STATFS);
521 return (error);
522 }
523
524 /*
525 * The FS type etc is copy from upper vfs.
526 * (write able vfs have priority)
527 */
528 sbp->f_type = mstat->f_type;
529 sbp->f_flags = mstat->f_flags;
530 sbp->f_bsize = mstat->f_bsize;
531 sbp->f_iosize = mstat->f_iosize;
532
533 if (mstat->f_bsize != lbsize)
534 sbp->f_blocks = ((off_t)sbp->f_blocks * lbsize) /
535 mstat->f_bsize;
536
537 sbp->f_blocks += mstat->f_blocks;
538 sbp->f_bfree = mstat->f_bfree;
539 sbp->f_bavail = mstat->f_bavail;
540 sbp->f_files += mstat->f_files;
541 sbp->f_ffree = mstat->f_ffree;
542
543 free(mstat, M_STATFS);
544 return (0);
545 }
546
547 static int
unionfs_sync(struct mount * mp,int waitfor)548 unionfs_sync(struct mount *mp, int waitfor)
549 {
550 /* nothing to do */
551 return (0);
552 }
553
554 static int
unionfs_vget(struct mount * mp,ino_t ino,int flags,struct vnode ** vpp)555 unionfs_vget(struct mount *mp, ino_t ino, int flags, struct vnode **vpp)
556 {
557 return (EOPNOTSUPP);
558 }
559
560 static int
unionfs_fhtovp(struct mount * mp,struct fid * fidp,int flags,struct vnode ** vpp)561 unionfs_fhtovp(struct mount *mp, struct fid *fidp, int flags,
562 struct vnode **vpp)
563 {
564 return (EOPNOTSUPP);
565 }
566
567 static int
unionfs_checkexp(struct mount * mp,struct sockaddr * nam,uint64_t * extflagsp,struct ucred ** credanonp,int * numsecflavors,int * secflavors)568 unionfs_checkexp(struct mount *mp, struct sockaddr *nam, uint64_t *extflagsp,
569 struct ucred **credanonp, int *numsecflavors, int *secflavors)
570 {
571 return (EOPNOTSUPP);
572 }
573
574 static int
unionfs_extattrctl(struct mount * mp,int cmd,struct vnode * filename_vp,int namespace,const char * attrname)575 unionfs_extattrctl(struct mount *mp, int cmd, struct vnode *filename_vp,
576 int namespace, const char *attrname)
577 {
578 struct unionfs_mount *ump;
579 struct unionfs_node *unp;
580
581 ump = MOUNTTOUNIONFSMOUNT(mp);
582 unp = VTOUNIONFS(filename_vp);
583
584 if (unp->un_uppervp != NULL) {
585 return (VFS_EXTATTRCTL(ump->um_uppermp, cmd,
586 unp->un_uppervp, namespace, attrname));
587 } else {
588 return (VFS_EXTATTRCTL(ump->um_lowermp, cmd,
589 unp->un_lowervp, namespace, attrname));
590 }
591 }
592
593 static struct vfsops unionfs_vfsops = {
594 .vfs_checkexp = unionfs_checkexp,
595 .vfs_extattrctl = unionfs_extattrctl,
596 .vfs_fhtovp = unionfs_fhtovp,
597 .vfs_init = unionfs_init,
598 .vfs_mount = unionfs_domount,
599 .vfs_quotactl = unionfs_quotactl,
600 .vfs_root = unionfs_root,
601 .vfs_statfs = unionfs_statfs,
602 .vfs_sync = unionfs_sync,
603 .vfs_uninit = unionfs_uninit,
604 .vfs_unmount = unionfs_unmount,
605 .vfs_vget = unionfs_vget,
606 };
607
608 VFS_SET(unionfs_vfsops, unionfs, VFCF_LOOPBACK);
609