xref: /netbsd-src/sys/fs/unionfs/unionfs_vnops.c (revision e61202360d5611414dd6f6115934a96aa1f50b1a)
1 /*-
2  * Copyright (c) 1992, 1993, 1994, 1995 Jan-Simon Pendry.
3  * Copyright (c) 1992, 1993, 1994, 1995
4  *      The Regents of the University of California.
5  * Copyright (c) 2005, 2006 Masanori Ozawa <ozawa@ongs.co.jp>, ONGS Inc.
6  * Copyright (c) 2006 Daichi Goto <daichi@freebsd.org>
7  * All rights reserved.
8  *
9  * This code is derived from software contributed to Berkeley by
10  * Jan-Simon Pendry.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
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  *	@(#)union_vnops.c	8.32 (Berkeley) 6/23/95
37  * $FreeBSD: src/sys/fs/unionfs/union_vnops.c,v 1.152 2008/01/13 14:44:06 attilio Exp $
38  *
39  */
40 
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/conf.h>
44 #include <sys/kernel.h>
45 #include <sys/lock.h>
46 #include <sys/malloc.h>
47 #include <sys/mount.h>
48 #include <sys/mutex.h>
49 #include <sys/namei.h>
50 #include <sys/sysctl.h>
51 #include <sys/vnode.h>
52 #include <sys/buf.h>
53 #include <sys/fcntl.h>
54 #include <sys/stat.h>
55 #include <sys/dirent.h>
56 #include <sys/proc.h>
57 
58 #include <fs/unionfs/unionfs.h>
59 
60 #if 0
61 #define UNIONFS_INTERNAL_DEBUG(msg, args...)    printf(msg, ## args)
62 #define UNIONFS_IDBG_RENAME
63 #else
64 #define UNIONFS_INTERNAL_DEBUG(msg, args...)
65 #endif
66 
67 static int
68 unionfs_lookup(void *v)
69 {
70 	struct vop_lookup_args *ap = v;
71 	int		iswhiteout;
72 	int		lockflag;
73 	int		error , uerror, lerror;
74 	u_long		nameiop;
75 	u_long		cnflags, cnflagsbk;
76 	struct unionfs_node *dunp;
77 	struct vnode   *dvp, *udvp, *ldvp, *vp, *uvp, *lvp, *dtmpvp;
78 	struct vattr	va;
79 	struct componentname *cnp;
80 
81 	iswhiteout = 0;
82 	lockflag = 0;
83 	error = uerror = lerror = ENOENT;
84 	cnp = ap->a_cnp;
85 	nameiop = cnp->cn_nameiop;
86 	cnflags = cnp->cn_flags;
87 	dvp = ap->a_dvp;
88 	dunp = VTOUNIONFS(dvp);
89 	udvp = dunp->un_uppervp;
90 	ldvp = dunp->un_lowervp;
91 	vp = uvp = lvp = NULLVP;
92 	*(ap->a_vpp) = NULLVP;
93 
94 	UNIONFS_INTERNAL_DEBUG("unionfs_lookup: enter: nameiop=%ld, flags=%lx, path=%s\n", nameiop, cnflags, cnp->cn_nameptr);
95 
96 	if (dvp->v_type != VDIR)
97 		return (ENOTDIR);
98 
99 	/*
100 	 * If read-only and op is not LOOKUP, will return EROFS.
101 	 */
102 	if ((cnflags & ISLASTCN) &&
103 	    (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
104 	    LOOKUP != nameiop)
105 		return (EROFS);
106 
107 	/*
108 	 * lookup dotdot
109 	 */
110 	if (cnflags & ISDOTDOT) {
111 		if (LOOKUP != nameiop && udvp == NULLVP)
112 			return (EROFS);
113 
114 		if (udvp != NULLVP) {
115 			dtmpvp = udvp;
116 			if (ldvp != NULLVP)
117 				VOP_UNLOCK(ldvp);
118 		}
119 		else
120 			dtmpvp = ldvp;
121 
122 		error = VOP_LOOKUP(dtmpvp, &vp, cnp);
123 
124 		if (dtmpvp == udvp && ldvp != NULLVP) {
125 			VOP_UNLOCK(udvp);
126 			vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
127 		}
128 
129 		if (error == 0) {
130 			/*
131 			 * Exchange lock and reference from vp to
132 			 * dunp->un_dvp. vp is upper/lower vnode, but it
133 			 * will need to return the unionfs vnode.
134 			 */
135 			if (nameiop == DELETE  || nameiop == RENAME)
136 				VOP_UNLOCK(vp);
137 			vrele(vp);
138 
139 			VOP_UNLOCK(dvp);
140 			*(ap->a_vpp) = dunp->un_dvp;
141 			vref(dunp->un_dvp);
142 
143 			vn_lock(dunp->un_dvp, LK_EXCLUSIVE | LK_RETRY);
144 			vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
145 		} else if (error == ENOENT && nameiop != CREATE)
146 			cache_enter(dvp, NULLVP, cnp);
147 
148 		UNIONFS_INTERNAL_DEBUG("unionfs_lookup: leave (%d)\n", error);
149 
150 		return (error);
151 	}
152 
153 	/*
154 	 * lookup upper layer
155 	 */
156 	if (udvp != NULLVP) {
157 		uerror = VOP_LOOKUP(udvp, &uvp, cnp);
158 
159 		if (uerror == 0) {
160 			if (udvp == uvp) {	/* is dot */
161 				vrele(uvp);
162 				*(ap->a_vpp) = dvp;
163 				vref(dvp);
164 
165 				UNIONFS_INTERNAL_DEBUG("unionfs_lookup: leave (%d)\n", uerror);
166 
167 				return (uerror);
168 			}
169 		}
170 
171 		/* check whiteout */
172 		if (uerror == ENOENT || uerror == EJUSTRETURN)
173 			if (cnp->cn_flags & ISWHITEOUT)
174 				iswhiteout = 1;	/* don't lookup lower */
175 		if (iswhiteout == 0 && ldvp != NULLVP)
176 			if (VOP_GETATTR(udvp, &va, cnp->cn_cred) == 0 &&
177 			    (va.va_flags & OPAQUE))
178 				iswhiteout = 1;	/* don't lookup lower */
179 #if 0
180 		UNIONFS_INTERNAL_DEBUG("unionfs_lookup: debug: whiteout=%d, path=%s\n", iswhiteout, cnp->cn_nameptr);
181 #endif
182 	}
183 
184 	/*
185 	 * lookup lower layer
186 	 */
187 	if (ldvp != NULLVP && !(cnflags & DOWHITEOUT) && iswhiteout == 0) {
188 		/* always op is LOOKUP */
189 		cnp->cn_nameiop = LOOKUP;
190 		cnflagsbk = cnp->cn_flags;
191 		cnp->cn_flags = cnflags;
192 
193 		lerror = VOP_LOOKUP(ldvp, &lvp, cnp);
194 
195 		cnp->cn_nameiop = nameiop;
196 		if (udvp != NULLVP && (uerror == 0 || uerror == EJUSTRETURN))
197 			cnp->cn_flags = cnflagsbk;
198 
199 		if (lerror == 0) {
200 			if (ldvp == lvp) {	/* is dot */
201 				if (uvp != NULLVP)
202 					vrele(uvp);	/* no need? */
203 				vrele(lvp);
204 				*(ap->a_vpp) = dvp;
205 				vref(dvp);
206 
207 				UNIONFS_INTERNAL_DEBUG("unionfs_lookup: leave (%d)\n", lerror);
208 				if (uvp != NULL)
209 					VOP_UNLOCK(uvp);
210 				return (lerror);
211 			}
212 		}
213 	}
214 
215 	/*
216 	 * check lookup result
217 	 */
218 	if (uvp == NULLVP && lvp == NULLVP) {
219 		UNIONFS_INTERNAL_DEBUG("unionfs_lookup: leave (%d)\n",
220 		    (udvp != NULLVP ? uerror : lerror));
221 		return (udvp != NULLVP ? uerror : lerror);
222 	}
223 
224 	/*
225 	 * check vnode type
226 	 */
227 	if (uvp != NULLVP && lvp != NULLVP && uvp->v_type != lvp->v_type) {
228 		vput(lvp);
229 		lvp = NULLVP;
230 	}
231 
232 	/*
233 	 * check shadow dir
234 	 */
235 	if (uerror != 0 && uerror != EJUSTRETURN && udvp != NULLVP &&
236 	    lerror == 0 && lvp != NULLVP && lvp->v_type == VDIR &&
237 	    !(dvp->v_mount->mnt_flag & MNT_RDONLY) &&
238 	    (1 < cnp->cn_namelen || '.' != *(cnp->cn_nameptr))) {
239 		/* get unionfs vnode in order to create a new shadow dir. */
240 		error = unionfs_nodeget(dvp->v_mount, NULLVP, lvp, dvp, &vp,
241 		    cnp);
242 		if (error != 0)
243 			goto unionfs_lookup_out;
244 		error = unionfs_mkshadowdir(MOUNTTOUNIONFSMOUNT(dvp->v_mount),
245 		    udvp, VTOUNIONFS(vp), cnp);
246 		if (error != 0) {
247 			UNIONFSDEBUG("unionfs_lookup: Unable to create shadow dir.");
248 			vput(vp);
249 			goto unionfs_lookup_out;
250 		}
251 	}
252 	/*
253 	 * get unionfs vnode.
254 	 */
255 	else {
256 		if (uvp != NULLVP)
257 			error = uerror;
258 		else
259 			error = lerror;
260 		if (error != 0)
261 			goto unionfs_lookup_out;
262 		error = unionfs_nodeget(dvp->v_mount, uvp, lvp, dvp, &vp, cnp);
263 		if (error != 0) {
264 			UNIONFSDEBUG("unionfs_lookup: Unable to create unionfs vnode.");
265 			goto unionfs_lookup_out;
266 		}
267 	}
268 
269 	*(ap->a_vpp) = vp;
270 
271 	cache_enter(dvp, vp, cnp);
272 
273 	/* XXXAD lock status on error */
274 unionfs_lookup_out:
275 	if (uvp != NULLVP)
276 		vrele(uvp);
277 	if (lvp != NULLVP)
278 		vrele(lvp);
279 
280 	if (error == ENOENT && nameiop != CREATE)
281 		cache_enter(dvp, NULLVP, cnp);
282 
283 	UNIONFS_INTERNAL_DEBUG("unionfs_lookup: leave (%d)\n", error);
284 
285 	return (error);
286 }
287 
288 static int
289 unionfs_create(void *v)
290 {
291 	struct vop_create_args *ap = v;
292 	struct unionfs_node *dunp;
293 	struct componentname *cnp;
294 	struct vnode   *udvp;
295 	struct vnode   *vp;
296 	int		error;
297 
298 	UNIONFS_INTERNAL_DEBUG("unionfs_create: enter\n");
299 
300 	dunp = VTOUNIONFS(ap->a_dvp);
301 	cnp = ap->a_cnp;
302 	udvp = dunp->un_uppervp;
303 	error = EROFS;
304 
305 	if (udvp != NULLVP) {
306 		if ((error = VOP_CREATE(udvp, &vp, cnp, ap->a_vap)) == 0) {
307 			error = unionfs_nodeget(ap->a_dvp->v_mount, vp, NULLVP,
308 			    ap->a_dvp, ap->a_vpp, cnp);
309 			if (error) {
310 				vput(vp);
311 			} else {
312 				vrele(vp);
313 			}
314 		}
315 	}
316 
317 	UNIONFS_INTERNAL_DEBUG("unionfs_create: leave (%d)\n", error);
318 
319 	return (error);
320 }
321 
322 static int
323 unionfs_whiteout(void *v)
324 {
325 	struct vop_whiteout_args *ap = v;
326 	struct unionfs_node *dunp;
327 	struct componentname *cnp;
328 	struct vnode   *udvp;
329 	int		error;
330 
331 	UNIONFS_INTERNAL_DEBUG("unionfs_whiteout: enter\n");
332 
333 	dunp = VTOUNIONFS(ap->a_dvp);
334 	cnp = ap->a_cnp;
335 	udvp = dunp->un_uppervp;
336 	error = EOPNOTSUPP;
337 
338 	if (udvp != NULLVP) {
339 		switch (ap->a_flags) {
340 		case CREATE:
341 		case DELETE:
342 		case LOOKUP:
343 			error = VOP_WHITEOUT(udvp, cnp, ap->a_flags);
344 			break;
345 		default:
346 			error = EINVAL;
347 			break;
348 		}
349 	}
350 
351 	UNIONFS_INTERNAL_DEBUG("unionfs_whiteout: leave (%d)\n", error);
352 
353 	return (error);
354 }
355 
356 static int
357 unionfs_mknod(void *v)
358 {
359 	struct vop_mknod_args *ap = v;
360 	struct unionfs_node *dunp;
361 	struct componentname *cnp;
362 	struct vnode   *udvp;
363 	struct vnode   *vp;
364 	int		error;
365 
366 	UNIONFS_INTERNAL_DEBUG("unionfs_mknod: enter\n");
367 
368 	dunp = VTOUNIONFS(ap->a_dvp);
369 	cnp = ap->a_cnp;
370 	udvp = dunp->un_uppervp;
371 	error = EROFS;
372 
373 	if (udvp != NULLVP) {
374 		if ((error = VOP_MKNOD(udvp, &vp, cnp, ap->a_vap)) == 0) {
375 			error = unionfs_nodeget(ap->a_dvp->v_mount, vp, NULLVP,
376 			    ap->a_dvp, ap->a_vpp, cnp);
377 			if (error) {
378 				vput(vp);
379 			} else {
380 				vrele(vp);
381 			}
382 		}
383 	}
384 
385 	UNIONFS_INTERNAL_DEBUG("unionfs_mknod: leave (%d)\n", error);
386 
387 	return (error);
388 }
389 
390 static int
391 unionfs_open(void *v)
392 {
393 	struct vop_open_args *ap = v;
394 	int		error;
395 	struct unionfs_node *unp;
396 	struct unionfs_node_status *unsp;
397 	struct vnode   *uvp;
398 	struct vnode   *lvp;
399 	struct vnode   *targetvp;
400 	kauth_cred_t   cred;
401 
402 	UNIONFS_INTERNAL_DEBUG("unionfs_open: enter\n");
403 
404 	error = 0;
405 	unp = VTOUNIONFS(ap->a_vp);
406 	uvp = unp->un_uppervp;
407 	lvp = unp->un_lowervp;
408 	targetvp = NULLVP;
409 	cred = ap->a_cred;
410 
411 	unionfs_get_node_status(unp, &unsp);
412 
413 	if (unsp->uns_lower_opencnt > 0 || unsp->uns_upper_opencnt > 0) {
414 		/* vnode is already opend. */
415 		if (unsp->uns_upper_opencnt > 0)
416 			targetvp = uvp;
417 		else
418 			targetvp = lvp;
419 
420 		if (targetvp == lvp &&
421 		    (ap->a_mode & FWRITE) && lvp->v_type == VREG)
422 			targetvp = NULLVP;
423 	}
424 	if (targetvp == NULLVP) {
425 		if (uvp == NULLVP) {
426 			if ((ap->a_mode & FWRITE) && lvp->v_type == VREG) {
427 				error = unionfs_copyfile(unp,
428 				    !(ap->a_mode & O_TRUNC), cred);
429 				if (error != 0)
430 					goto unionfs_open_abort;
431 				targetvp = uvp = unp->un_uppervp;
432 			} else
433 				targetvp = lvp;
434 		} else
435 			targetvp = uvp;
436 	}
437 
438 	error = VOP_OPEN(targetvp, ap->a_mode, cred);
439 	if (error == 0) {
440 		if (targetvp == uvp) {
441 			if (uvp->v_type == VDIR && lvp != NULLVP &&
442 			    unsp->uns_lower_opencnt <= 0) {
443 				/* open lower for readdir */
444 				error = VOP_OPEN(lvp, FREAD, cred);
445 				if (error != 0) {
446 					VOP_CLOSE(uvp, ap->a_mode, cred);
447 					goto unionfs_open_abort;
448 				}
449 				unsp->uns_node_flag |= UNS_OPENL_4_READDIR;
450 				unsp->uns_lower_opencnt++;
451 			}
452 			unsp->uns_upper_opencnt++;
453 		} else {
454 			unsp->uns_lower_opencnt++;
455 			unsp->uns_lower_openmode = ap->a_mode;
456 		}
457 	}
458 
459 unionfs_open_abort:
460 	if (error != 0)
461 		unionfs_tryrem_node_status(unp, unsp);
462 
463 	UNIONFS_INTERNAL_DEBUG("unionfs_open: leave (%d)\n", error);
464 
465 	return (error);
466 }
467 
468 static int
469 unionfs_close(void *v)
470 {
471 	struct vop_close_args *ap = v;
472 	int		error;
473 	struct unionfs_node *unp;
474 	struct unionfs_node_status *unsp;
475 	kauth_cred_t   cred;
476 	struct vnode   *ovp;
477 
478 	UNIONFS_INTERNAL_DEBUG("unionfs_close: enter\n");
479 
480 	KASSERT(VOP_ISLOCKED(ap->a_vp) == LK_EXCLUSIVE);
481 	unp = VTOUNIONFS(ap->a_vp);
482 	cred = ap->a_cred;
483 
484 	unionfs_get_node_status(unp, &unsp);
485 
486 	if (unsp->uns_lower_opencnt <= 0 && unsp->uns_upper_opencnt <= 0) {
487 #ifdef DIAGNOSTIC
488 		printf("unionfs_close: warning: open count is 0\n");
489 #endif
490 		if (unp->un_uppervp != NULLVP)
491 			ovp = unp->un_uppervp;
492 		else
493 			ovp = unp->un_lowervp;
494 	} else if (unsp->uns_upper_opencnt > 0)
495 		ovp = unp->un_uppervp;
496 	else
497 		ovp = unp->un_lowervp;
498 
499 	error = VOP_CLOSE(ovp, ap->a_fflag, cred);
500 
501 	if (error != 0)
502 		goto unionfs_close_abort;
503 
504 	if (ovp == unp->un_uppervp) {
505 		unsp->uns_upper_opencnt--;
506 		if (unsp->uns_upper_opencnt == 0) {
507 			if (unsp->uns_node_flag & UNS_OPENL_4_READDIR) {
508 				VOP_CLOSE(unp->un_lowervp, FREAD, cred);
509 				unsp->uns_node_flag &= ~UNS_OPENL_4_READDIR;
510 				unsp->uns_lower_opencnt--;
511 			}
512 		}
513 	} else
514 		unsp->uns_lower_opencnt--;
515 
516 unionfs_close_abort:
517 	unionfs_tryrem_node_status(unp, unsp);
518 
519 	UNIONFS_INTERNAL_DEBUG("unionfs_close: leave (%d)\n", error);
520 
521 	return (error);
522 }
523 
524 /*
525  * Check the access mode toward shadow file/dir.
526  */
527 static int
528 unionfs_check_corrected_access(u_short mode, struct vattr *va, kauth_cred_t cred)
529 {
530 	int		result;
531 	int		error;
532 	uid_t		uid;	/* upper side vnode's uid */
533 	gid_t		gid;	/* upper side vnode's gid */
534 	u_short		vmode;	/* upper side vnode's mode */
535 	u_short		mask;
536 
537 	mask = 0;
538 	uid = va->va_uid;
539 	gid = va->va_gid;
540 	vmode = va->va_mode;
541 
542 	/* check owner */
543 	if (kauth_cred_getuid(cred) == uid) {
544 		if (mode & VEXEC)
545 			mask |= S_IXUSR;
546 		if (mode & VREAD)
547 			mask |= S_IRUSR;
548 		if (mode & VWRITE)
549 			mask |= S_IWUSR;
550 		return ((vmode & mask) == mask ? 0 : EACCES);
551 	}
552 
553 	/* check group */
554 	error = kauth_cred_ismember_gid(cred, gid, &result);
555 	if (error != 0)
556 		return error;
557 	if (result) {
558 		if (mode & VEXEC)
559 			mask |= S_IXGRP;
560 		if (mode & VREAD)
561 			mask |= S_IRGRP;
562 		if (mode & VWRITE)
563 			mask |= S_IWGRP;
564 		return ((vmode & mask) == mask ? 0 : EACCES);
565 	}
566 
567 	/* check other */
568 	if (mode & VEXEC)
569 		mask |= S_IXOTH;
570 	if (mode & VREAD)
571 		mask |= S_IROTH;
572 	if (mode & VWRITE)
573 		mask |= S_IWOTH;
574 
575 	return ((vmode & mask) == mask ? 0 : EACCES);
576 }
577 
578 static int
579 unionfs_access(void *v)
580 {
581 	struct vop_access_args *ap = v;
582 	struct unionfs_mount *ump;
583 	struct unionfs_node *unp;
584 	struct vnode   *uvp;
585 	struct vnode   *lvp;
586 	struct vattr	va;
587 	int		mode;
588 	int		error;
589 
590 	UNIONFS_INTERNAL_DEBUG("unionfs_access: enter\n");
591 
592 	ump = MOUNTTOUNIONFSMOUNT(ap->a_vp->v_mount);
593 	unp = VTOUNIONFS(ap->a_vp);
594 	uvp = unp->un_uppervp;
595 	lvp = unp->un_lowervp;
596 	mode = ap->a_mode;
597 	error = EACCES;
598 
599 	if ((mode & VWRITE) &&
600 	    (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)) {
601 		switch (ap->a_vp->v_type) {
602 		case VREG:
603 		case VDIR:
604 		case VLNK:
605 			return (EROFS);
606 		default:
607 			break;
608 		}
609 	}
610 
611 	if (uvp != NULLVP) {
612 		error = VOP_ACCESS(uvp, mode, ap->a_cred);
613 
614 		UNIONFS_INTERNAL_DEBUG("unionfs_access: leave (%d)\n", error);
615 
616 		return (error);
617 	}
618 
619 	if (lvp != NULLVP) {
620 		if (mode & VWRITE) {
621 			if (ump->um_uppervp->v_mount->mnt_flag & MNT_RDONLY) {
622 				switch (ap->a_vp->v_type) {
623 				case VREG:
624 				case VDIR:
625 				case VLNK:
626 					return (EROFS);
627 				default:
628 					break;
629 				}
630 			} else if (ap->a_vp->v_type == VREG || ap->a_vp->v_type == VDIR) {
631 				/* check shadow file/dir */
632 				if (ump->um_copymode != UNIONFS_TRANSPARENT) {
633 					error = unionfs_create_uppervattr(ump,
634 					    lvp, &va, ap->a_cred);
635 					if (error != 0)
636 						return (error);
637 
638 					error = unionfs_check_corrected_access(
639 					    mode, &va, ap->a_cred);
640 					if (error != 0)
641 						return (error);
642 				}
643 			}
644 			mode &= ~VWRITE;
645 			mode |= VREAD; /* will copy to upper */
646 		}
647 		error = VOP_ACCESS(lvp, mode, ap->a_cred);
648 	}
649 
650 	UNIONFS_INTERNAL_DEBUG("unionfs_access: leave (%d)\n", error);
651 
652 	return (error);
653 }
654 
655 static int
656 unionfs_getattr(void *v)
657 {
658 	struct vop_getattr_args *ap = v;
659 	int		error;
660 	struct unionfs_node *unp;
661 	struct unionfs_mount *ump;
662 	struct vnode   *uvp;
663 	struct vnode   *lvp;
664 	struct vattr	va;
665 
666 	UNIONFS_INTERNAL_DEBUG("unionfs_getattr: enter\n");
667 
668 	unp = VTOUNIONFS(ap->a_vp);
669 	ump = MOUNTTOUNIONFSMOUNT(ap->a_vp->v_mount);
670 	uvp = unp->un_uppervp;
671 	lvp = unp->un_lowervp;
672 
673 	if (uvp != NULLVP) {
674 		if ((error = VOP_GETATTR(uvp, ap->a_vap, ap->a_cred)) == 0)
675 			ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid;
676 
677 		UNIONFS_INTERNAL_DEBUG("unionfs_getattr: leave mode=%o, uid=%d, gid=%d (%d)\n",
678 		    ap->a_vap->va_mode, ap->a_vap->va_uid,
679 		    ap->a_vap->va_gid, error);
680 
681 		return (error);
682 	}
683 
684 	error = VOP_GETATTR(lvp, ap->a_vap, ap->a_cred);
685 
686 	if (error == 0 && !(ump->um_uppervp->v_mount->mnt_flag & MNT_RDONLY)) {
687 		/* correct the attr toward shadow file/dir. */
688 		if (ap->a_vp->v_type == VREG || ap->a_vp->v_type == VDIR) {
689 			unionfs_create_uppervattr_core(ump, ap->a_vap, &va);
690 			ap->a_vap->va_mode = va.va_mode;
691 			ap->a_vap->va_uid = va.va_uid;
692 			ap->a_vap->va_gid = va.va_gid;
693 		}
694 	}
695 
696 	if (error == 0)
697 		ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid;
698 
699 	UNIONFS_INTERNAL_DEBUG("unionfs_getattr: leave mode=%o, uid=%d, gid=%d (%d)\n",
700 	    ap->a_vap->va_mode, ap->a_vap->va_uid, ap->a_vap->va_gid, error);
701 
702 	return (error);
703 }
704 
705 static int
706 unionfs_setattr(void *v)
707 {
708 	struct vop_setattr_args *ap = v;
709 	int		error;
710 	struct unionfs_node *unp;
711 	struct vnode   *uvp;
712 	struct vnode   *lvp;
713 	struct vattr   *vap;
714 
715 	UNIONFS_INTERNAL_DEBUG("unionfs_setattr: enter\n");
716 
717 	error = EROFS;
718 	unp = VTOUNIONFS(ap->a_vp);
719 	uvp = unp->un_uppervp;
720 	lvp = unp->un_lowervp;
721 	vap = ap->a_vap;
722 
723 	if ((ap->a_vp->v_mount->mnt_flag & MNT_RDONLY) &&
724 	    (vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
725 	     vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
726 	     vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL))
727 		return (EROFS);
728 
729 	if (uvp == NULLVP && lvp->v_type == VREG) {
730 		error = unionfs_copyfile(unp, (vap->va_size != 0),
731 		    ap->a_cred);
732 		if (error != 0)
733 			return (error);
734 		uvp = unp->un_uppervp;
735 	}
736 
737 	if (uvp != NULLVP)
738 		error = VOP_SETATTR(uvp, vap, ap->a_cred);
739 
740 	UNIONFS_INTERNAL_DEBUG("unionfs_setattr: leave (%d)\n", error);
741 
742 	return (error);
743 }
744 
745 static int
746 unionfs_read(void *v)
747 {
748 	struct vop_read_args *ap = v;
749 	int		error;
750 	struct unionfs_node *unp;
751 	struct vnode   *tvp;
752 
753 	/* UNIONFS_INTERNAL_DEBUG("unionfs_read: enter\n"); */
754 
755 	unp = VTOUNIONFS(ap->a_vp);
756 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
757 
758 	error = VOP_READ(tvp, ap->a_uio, ap->a_ioflag, ap->a_cred);
759 
760 	/* UNIONFS_INTERNAL_DEBUG("unionfs_read: leave (%d)\n", error); */
761 
762 	return (error);
763 }
764 
765 static int
766 unionfs_write(void *v)
767 {
768 	struct vop_write_args *ap = v;
769 	int		error;
770 	struct unionfs_node *unp;
771 	struct vnode   *tvp;
772 
773 	/* UNIONFS_INTERNAL_DEBUG("unionfs_write: enter\n"); */
774 
775 	unp = VTOUNIONFS(ap->a_vp);
776 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
777 
778 	error = VOP_WRITE(tvp, ap->a_uio, ap->a_ioflag, ap->a_cred);
779 
780 	/* UNIONFS_INTERNAL_DEBUG("unionfs_write: leave (%d)\n", error); */
781 
782 	return (error);
783 }
784 
785 static int
786 unionfs_ioctl(void *v)
787 {
788 	struct vop_ioctl_args *ap = v;
789 	int error;
790 	struct unionfs_node *unp;
791 	struct unionfs_node_status *unsp;
792 	struct vnode   *ovp;
793 
794 	UNIONFS_INTERNAL_DEBUG("unionfs_ioctl: enter\n");
795 
796  	vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
797 	unp = VTOUNIONFS(ap->a_vp);
798 	unionfs_get_node_status(unp, &unsp);
799 	ovp = (unsp->uns_upper_opencnt ? unp->un_uppervp : unp->un_lowervp);
800 	unionfs_tryrem_node_status(unp, unsp);
801 	VOP_UNLOCK(ap->a_vp);
802 
803 	if (ovp == NULLVP)
804 		return (EBADF);
805 
806 	error = VOP_IOCTL(ovp, ap->a_command, ap->a_data, ap->a_fflag,
807 	    ap->a_cred);
808 
809 	UNIONFS_INTERNAL_DEBUG("unionfs_ioctl: lease (%d)\n", error);
810 
811 	return (error);
812 }
813 
814 static int
815 unionfs_poll(void *v)
816 {
817 	struct vop_poll_args *ap = v;
818 	struct unionfs_node *unp;
819 	struct unionfs_node_status *unsp;
820 	struct vnode   *ovp;
821 
822  	vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
823 	unp = VTOUNIONFS(ap->a_vp);
824 	unionfs_get_node_status(unp, &unsp);
825 	ovp = (unsp->uns_upper_opencnt ? unp->un_uppervp : unp->un_lowervp);
826 	unionfs_tryrem_node_status(unp, unsp);
827 	VOP_UNLOCK(ap->a_vp);
828 
829 	if (ovp == NULLVP)
830 		return (EBADF);
831 
832 	return (VOP_POLL(ovp, ap->a_events));
833 }
834 
835 static int
836 unionfs_fsync(void *v)
837 {
838 	struct vop_fsync_args *ap = v;
839 	struct unionfs_node *unp;
840 	struct unionfs_node_status *unsp;
841 	struct vnode   *ovp;
842 
843 	unp = VTOUNIONFS(ap->a_vp);
844 	unionfs_get_node_status(unp, &unsp);
845 	ovp = (unsp->uns_upper_opencnt ? unp->un_uppervp : unp->un_lowervp);
846 	unionfs_tryrem_node_status(unp, unsp);
847 
848 	if (ovp == NULLVP)
849 		return (EBADF);
850 
851 	return (VOP_FSYNC(ovp, ap->a_cred, ap->a_flags, ap->a_offlo, ap->a_offhi));
852 }
853 
854 static int
855 unionfs_remove(void *v)
856 {
857 	struct vop_remove_args *ap = v;
858 	int		error;
859 	struct unionfs_node *dunp;
860 	struct unionfs_node *unp;
861 	struct unionfs_mount *ump;
862 	struct vnode   *udvp;
863 	struct vnode   *uvp;
864 	struct vnode   *lvp;
865 	struct componentname *cnp;
866 
867 	UNIONFS_INTERNAL_DEBUG("unionfs_remove: enter\n");
868 
869 	error = 0;
870 	dunp = VTOUNIONFS(ap->a_dvp);
871 	unp = VTOUNIONFS(ap->a_vp);
872 	udvp = dunp->un_uppervp;
873 	uvp = unp->un_uppervp;
874 	lvp = unp->un_lowervp;
875 	cnp = ap->a_cnp;
876 
877 	if (udvp == NULLVP)
878 		return (EROFS);
879 
880 	if (uvp != NULLVP) {
881 		ump = MOUNTTOUNIONFSMOUNT(ap->a_vp->v_mount);
882 		if (ump->um_whitemode == UNIONFS_WHITE_ALWAYS || lvp != NULLVP)
883 			cnp->cn_flags |= DOWHITEOUT;
884 		error = VOP_REMOVE(udvp, uvp, cnp);
885 	} else if (lvp != NULLVP)
886 		error = unionfs_mkwhiteout(udvp, cnp, unp->un_path);
887 
888 	UNIONFS_INTERNAL_DEBUG("unionfs_remove: leave (%d)\n", error);
889 
890 	return (error);
891 }
892 
893 static int
894 unionfs_link(void *v)
895 {
896 #if 0
897 	struct vop_link_args *ap = v;
898 	int		error;
899 	int		needrelookup;
900 	struct unionfs_node *dunp;
901 	struct unionfs_node *unp;
902 	struct vnode   *udvp;
903 	struct vnode   *uvp;
904 	struct componentname *cnp;
905 
906 	UNIONFS_INTERNAL_DEBUG("unionfs_link: enter\n");
907 
908 	error = 0;
909 	needrelookup = 0;
910 	dunp = VTOUNIONFS(ap->a_tdvp);
911 	unp = NULL;
912 	udvp = dunp->un_uppervp;
913 	uvp = NULLVP;
914 	cnp = ap->a_cnp;
915 
916 	if (udvp == NULLVP)
917 		return (EROFS);
918 
919 	if (ap->a_vp->v_op != unionfs_vnodeop_p)
920 		uvp = ap->a_vp;
921 	else {
922 		unp = VTOUNIONFS(ap->a_vp);
923 
924 		if (unp->un_uppervp == NULLVP) {
925 			if (ap->a_vp->v_type != VREG)
926 				return (EOPNOTSUPP);
927 
928 			error = unionfs_copyfile(unp, 1, cnp->cn_cred);
929 			if (error != 0)
930 				return (error);
931 			needrelookup = 1;
932 		}
933 		uvp = unp->un_uppervp;
934 	}
935 
936 	if (needrelookup != 0)
937 		error = unionfs_relookup_for_create(ap->a_tdvp, cnp);
938 
939 	if (error == 0)
940 		error = VOP_LINK(udvp, uvp, cnp);
941 
942 	UNIONFS_INTERNAL_DEBUG("unionfs_link: leave (%d)\n", error);
943 
944 	return (error);
945 #else
946 	panic("XXXAD");
947 	return 0;
948 #endif
949 }
950 
951 static int
952 unionfs_rename(void *v)
953 {
954 	struct vop_rename_args *ap = v;
955 	int		error;
956 	struct vnode   *fdvp;
957 	struct vnode   *fvp;
958 	struct componentname *fcnp;
959 	struct vnode   *tdvp;
960 	struct vnode   *tvp;
961 	struct componentname *tcnp;
962 	struct vnode   *ltdvp;
963 	struct vnode   *ltvp;
964 
965 	/* rename target vnodes */
966 	struct vnode   *rfdvp;
967 	struct vnode   *rfvp;
968 	struct vnode   *rtdvp;
969 	struct vnode   *rtvp;
970 
971 	int		needrelookup;
972 	struct unionfs_mount *ump;
973 	struct unionfs_node *unp;
974 
975 	UNIONFS_INTERNAL_DEBUG("unionfs_rename: enter\n");
976 
977 	error = 0;
978 	fdvp = ap->a_fdvp;
979 	fvp = ap->a_fvp;
980 	fcnp = ap->a_fcnp;
981 	tdvp = ap->a_tdvp;
982 	tvp = ap->a_tvp;
983 	tcnp = ap->a_tcnp;
984 	ltdvp = NULLVP;
985 	ltvp = NULLVP;
986 	rfdvp = fdvp;
987 	rfvp = fvp;
988 	rtdvp = tdvp;
989 	rtvp = tvp;
990 	needrelookup = 0;
991 
992 	/* check for cross device rename */
993 	if (fvp->v_mount != tdvp->v_mount ||
994 	    (tvp != NULLVP && fvp->v_mount != tvp->v_mount)) {
995 		error = EXDEV;
996 		goto unionfs_rename_abort;
997 	}
998 
999 	/* Renaming a file to itself has no effect. */
1000 	if (fvp == tvp)
1001 		goto unionfs_rename_abort;
1002 
1003 	/*
1004 	 * from/to vnode is unionfs node.
1005 	 */
1006 
1007 	unp = VTOUNIONFS(fdvp);
1008 #ifdef UNIONFS_IDBG_RENAME
1009 	UNIONFS_INTERNAL_DEBUG("fdvp=%p, ufdvp=%p, lfdvp=%p\n", fdvp, unp->un_uppervp, unp->un_lowervp);
1010 #endif
1011 	if (unp->un_uppervp == NULLVP) {
1012 		error = ENODEV;
1013 		goto unionfs_rename_abort;
1014 	}
1015 	rfdvp = unp->un_uppervp;
1016 	vref(rfdvp);
1017 
1018 	unp = VTOUNIONFS(fvp);
1019 #ifdef UNIONFS_IDBG_RENAME
1020 	UNIONFS_INTERNAL_DEBUG("fvp=%p, ufvp=%p, lfvp=%p\n", fvp, unp->un_uppervp, unp->un_lowervp);
1021 #endif
1022 	ump = MOUNTTOUNIONFSMOUNT(fvp->v_mount);
1023 	if (unp->un_uppervp == NULLVP) {
1024 		switch (fvp->v_type) {
1025 		case VREG:
1026 			if ((error = vn_lock(fvp, LK_EXCLUSIVE)) != 0)
1027 				goto unionfs_rename_abort;
1028 			error = unionfs_copyfile(unp, 1, fcnp->cn_cred);
1029 			VOP_UNLOCK(fvp);
1030 			if (error != 0)
1031 				goto unionfs_rename_abort;
1032 			break;
1033 		case VDIR:
1034 			if ((error = vn_lock(fvp, LK_EXCLUSIVE)) != 0)
1035 				goto unionfs_rename_abort;
1036 			error = unionfs_mkshadowdir(ump, rfdvp, unp, fcnp);
1037 			VOP_UNLOCK(fvp);
1038 			if (error != 0)
1039 				goto unionfs_rename_abort;
1040 			break;
1041 		default:
1042 			error = ENODEV;
1043 			goto unionfs_rename_abort;
1044 		}
1045 
1046 		needrelookup = 1;
1047 	}
1048 
1049 	if (unp->un_lowervp != NULLVP)
1050 		fcnp->cn_flags |= DOWHITEOUT;
1051 	rfvp = unp->un_uppervp;
1052 	vref(rfvp);
1053 
1054 	unp = VTOUNIONFS(tdvp);
1055 #ifdef UNIONFS_IDBG_RENAME
1056 	UNIONFS_INTERNAL_DEBUG("tdvp=%p, utdvp=%p, ltdvp=%p\n", tdvp, unp->un_uppervp, unp->un_lowervp);
1057 #endif
1058 	if (unp->un_uppervp == NULLVP) {
1059 		error = ENODEV;
1060 		goto unionfs_rename_abort;
1061 	}
1062 	rtdvp = unp->un_uppervp;
1063 	ltdvp = unp->un_lowervp;
1064 	vref(rtdvp);
1065 
1066 	if (tdvp == tvp) {
1067 		rtvp = rtdvp;
1068 		vref(rtvp);
1069 	} else if (tvp != NULLVP) {
1070 		unp = VTOUNIONFS(tvp);
1071 #ifdef UNIONFS_IDBG_RENAME
1072 		UNIONFS_INTERNAL_DEBUG("tvp=%p, utvp=%p, ltvp=%p\n", tvp, unp->un_uppervp, unp->un_lowervp);
1073 #endif
1074 		if (unp->un_uppervp == NULLVP)
1075 			rtvp = NULLVP;
1076 		else {
1077 			if (tvp->v_type == VDIR) {
1078 				error = EINVAL;
1079 				goto unionfs_rename_abort;
1080 			}
1081 			rtvp = unp->un_uppervp;
1082 			ltvp = unp->un_lowervp;
1083 			vref(rtvp);
1084 		}
1085 	}
1086 
1087 	if (needrelookup != 0) {
1088 		if ((error = vn_lock(fdvp, LK_EXCLUSIVE)) != 0)
1089 			goto unionfs_rename_abort;
1090 		error = unionfs_relookup_for_delete(fdvp, fcnp);
1091 		VOP_UNLOCK(fdvp);
1092 		if (error != 0)
1093 			goto unionfs_rename_abort;
1094 
1095 		/* Locke of tvp is canceled in order to avoid recursive lock. */
1096 		if (tvp != NULLVP && tvp != tdvp)
1097 			VOP_UNLOCK(tvp);
1098 		error = unionfs_relookup_for_rename(tdvp, tcnp);
1099 		if (tvp != NULLVP && tvp != tdvp)
1100 			vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY);
1101 		if (error != 0)
1102 			goto unionfs_rename_abort;
1103 	}
1104 
1105 	error = VOP_RENAME(rfdvp, rfvp, fcnp, rtdvp, rtvp, tcnp);
1106 
1107 	if (error == 0) {
1108 		if (rtvp != NULLVP && rtvp->v_type == VDIR)
1109 			cache_purge(tdvp);
1110 		if (fvp->v_type == VDIR && fdvp != tdvp)
1111 			cache_purge(fdvp);
1112 	}
1113 
1114 	if (fdvp != rfdvp)
1115 		vrele(fdvp);
1116 	if (fvp != rfvp)
1117 		vrele(fvp);
1118 	if (ltdvp != NULLVP)
1119 		VOP_UNLOCK(ltdvp);
1120 	if (tdvp != rtdvp)
1121 		vrele(tdvp);
1122 	if (ltvp != NULLVP)
1123 		VOP_UNLOCK(ltvp);
1124 	if (tvp != rtvp && tvp != NULLVP) {
1125 		if (rtvp == NULLVP)
1126 			vput(tvp);
1127 		else
1128 			vrele(tvp);
1129 	}
1130 
1131 	UNIONFS_INTERNAL_DEBUG("unionfs_rename: leave (%d)\n", error);
1132 
1133 	return (error);
1134 
1135 unionfs_rename_abort:
1136 	if (fdvp != rfdvp)
1137 		vrele(rfdvp);
1138 	if (fvp != rfvp)
1139 		vrele(rfvp);
1140 	if (tdvp != rtdvp)
1141 		vrele(rtdvp);
1142 	vput(tdvp);
1143 	if (tvp != rtvp && rtvp != NULLVP)
1144 		vrele(rtvp);
1145 	if (tvp != NULLVP) {
1146 		if (tdvp != tvp)
1147 			vput(tvp);
1148 		else
1149 			vrele(tvp);
1150 	}
1151 	vrele(fdvp);
1152 	vrele(fvp);
1153 
1154 	UNIONFS_INTERNAL_DEBUG("unionfs_rename: leave (%d)\n", error);
1155 
1156 	return (error);
1157 }
1158 
1159 static int
1160 unionfs_mkdir(void *v)
1161 {
1162 	struct vop_mkdir_args *ap = v;
1163 	int		error;
1164 	struct unionfs_node *dunp;
1165 	struct componentname *cnp;
1166 	struct vnode   *udvp;
1167 	struct vnode   *uvp;
1168 	struct vattr	va;
1169 
1170 	UNIONFS_INTERNAL_DEBUG("unionfs_mkdir: enter\n");
1171 
1172 	error = EROFS;
1173 	dunp = VTOUNIONFS(ap->a_dvp);
1174 	cnp = ap->a_cnp;
1175 	udvp = dunp->un_uppervp;
1176 
1177 	if (udvp != NULLVP) {
1178 		/* check opaque */
1179 		if (!(cnp->cn_flags & ISWHITEOUT)) {
1180 			error = VOP_GETATTR(udvp, &va, cnp->cn_cred);
1181 			if (error != 0)
1182 				return (error);
1183 			if (va.va_flags & OPAQUE)
1184 				cnp->cn_flags |= ISWHITEOUT;
1185 		}
1186 
1187 		if ((error = VOP_MKDIR(udvp, &uvp, cnp, ap->a_vap)) == 0) {
1188 			error = unionfs_nodeget(ap->a_dvp->v_mount, uvp, NULLVP,
1189 			    ap->a_dvp, ap->a_vpp, cnp);
1190 			if (error) {
1191 				vput(uvp);
1192 			} else {
1193 				vrele(uvp);
1194 			}
1195 		}
1196 	}
1197 
1198 	UNIONFS_INTERNAL_DEBUG("unionfs_mkdir: leave (%d)\n", error);
1199 
1200 	return (error);
1201 }
1202 
1203 static int
1204 unionfs_rmdir(void *v)
1205 {
1206 	struct vop_rmdir_args *ap = v;
1207 	int		error;
1208 	struct unionfs_node *dunp;
1209 	struct unionfs_node *unp;
1210 	struct unionfs_mount *ump;
1211 	struct componentname *cnp;
1212 	struct vnode   *udvp;
1213 	struct vnode   *uvp;
1214 	struct vnode   *lvp;
1215 
1216 	UNIONFS_INTERNAL_DEBUG("unionfs_rmdir: enter\n");
1217 
1218 	error = 0;
1219 	dunp = VTOUNIONFS(ap->a_dvp);
1220 	unp = VTOUNIONFS(ap->a_vp);
1221 	cnp = ap->a_cnp;
1222 	udvp = dunp->un_uppervp;
1223 	uvp = unp->un_uppervp;
1224 	lvp = unp->un_lowervp;
1225 
1226 	if (udvp == NULLVP)
1227 		return (EROFS);
1228 
1229 	if (udvp == uvp)
1230 		return (EOPNOTSUPP);
1231 
1232 	if (uvp != NULLVP) {
1233 		if (lvp != NULLVP) {
1234 			error = unionfs_check_rmdir(ap->a_vp, cnp->cn_cred);
1235 			if (error != 0)
1236 				return (error);
1237 		}
1238 		ump = MOUNTTOUNIONFSMOUNT(ap->a_vp->v_mount);
1239 		if (ump->um_whitemode == UNIONFS_WHITE_ALWAYS || lvp != NULLVP)
1240 			cnp->cn_flags |= DOWHITEOUT;
1241 		error = VOP_RMDIR(udvp, uvp, cnp);
1242 	}
1243 	else if (lvp != NULLVP)
1244 		error = unionfs_mkwhiteout(udvp, cnp, unp->un_path);
1245 
1246 	if (error == 0) {
1247 		cache_purge(ap->a_dvp);
1248 		cache_purge(ap->a_vp);
1249 	}
1250 
1251 	UNIONFS_INTERNAL_DEBUG("unionfs_rmdir: leave (%d)\n", error);
1252 
1253 	return (error);
1254 }
1255 
1256 static int
1257 unionfs_symlink(void *v)
1258 {
1259 	struct vop_symlink_args *ap = v;
1260 	int		error;
1261 	struct unionfs_node *dunp;
1262 	struct componentname *cnp;
1263 	struct vnode   *udvp;
1264 	struct vnode   *uvp;
1265 
1266 	UNIONFS_INTERNAL_DEBUG("unionfs_symlink: enter\n");
1267 
1268 	error = EROFS;
1269 	dunp = VTOUNIONFS(ap->a_dvp);
1270 	cnp = ap->a_cnp;
1271 	udvp = dunp->un_uppervp;
1272 
1273 	if (udvp != NULLVP) {
1274 		error = VOP_SYMLINK(udvp, &uvp, cnp, ap->a_vap, ap->a_target);
1275 		if (error == 0) {
1276 			error = unionfs_nodeget(ap->a_dvp->v_mount, uvp, NULLVP,
1277 			    ap->a_dvp, ap->a_vpp, cnp);
1278 			if (error) {
1279 				vput(uvp);
1280 			} else {
1281 				vrele(uvp);
1282 			}
1283 		}
1284 	}
1285 
1286 	UNIONFS_INTERNAL_DEBUG("unionfs_symlink: leave (%d)\n", error);
1287 
1288 	return (error);
1289 }
1290 
1291 static int
1292 unionfs_readdir(void *v)
1293 {
1294 	struct vop_readdir_args *ap = v;
1295 	int		error;
1296 	int		eofflag;
1297 	int		locked;
1298 	struct unionfs_node *unp;
1299 	struct unionfs_node_status *unsp;
1300 	struct uio     *uio;
1301 	struct vnode   *uvp;
1302 	struct vnode   *lvp;
1303 	struct vattr    va;
1304 
1305 	int		ncookies_bk;
1306 	off_t          *cookies_bk;
1307 
1308 	UNIONFS_INTERNAL_DEBUG("unionfs_readdir: enter\n");
1309 
1310 	error = 0;
1311 	eofflag = 0;
1312 	locked = 0;
1313 	unp = VTOUNIONFS(ap->a_vp);
1314 	uio = ap->a_uio;
1315 	uvp = unp->un_uppervp;
1316 	lvp = unp->un_lowervp;
1317 	ncookies_bk = 0;
1318 	cookies_bk = NULL;
1319 
1320 	if (ap->a_vp->v_type != VDIR)
1321 		return (ENOTDIR);
1322 
1323 	/* check opaque */
1324 	if (uvp != NULLVP && lvp != NULLVP) {
1325 		if ((error = VOP_GETATTR(uvp, &va, ap->a_cred)) != 0)
1326 			goto unionfs_readdir_exit;
1327 		if (va.va_flags & OPAQUE)
1328 			lvp = NULLVP;
1329 	}
1330 
1331 	/* check the open count. unionfs needs to open before readdir. */
1332 	VOP_UNLOCK(ap->a_vp);
1333 	vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
1334 	unionfs_get_node_status(unp, &unsp);
1335 	if ((uvp != NULLVP && unsp->uns_upper_opencnt <= 0) ||
1336 	    (lvp != NULLVP && unsp->uns_lower_opencnt <= 0)) {
1337 		unionfs_tryrem_node_status(unp, unsp);
1338 		error = EBADF;
1339 	}
1340 	if (error != 0)
1341 		goto unionfs_readdir_exit;
1342 
1343 	/* upper only */
1344 	if (uvp != NULLVP && lvp == NULLVP) {
1345 		error = VOP_READDIR(uvp, uio, ap->a_cred, ap->a_eofflag,
1346 		    ap->a_cookies, ap->a_ncookies);
1347 		unsp->uns_readdir_status = 0;
1348 
1349 		goto unionfs_readdir_exit;
1350 	}
1351 
1352 	/* lower only */
1353 	if (uvp == NULLVP && lvp != NULLVP) {
1354 		error = VOP_READDIR(lvp, uio, ap->a_cred, ap->a_eofflag,
1355 		    ap->a_cookies, ap->a_ncookies);
1356 		unsp->uns_readdir_status = 2;
1357 
1358 		goto unionfs_readdir_exit;
1359 	}
1360 
1361 	/*
1362 	 * readdir upper and lower
1363 	 */
1364 	KASSERT(uvp != NULLVP);
1365 	KASSERT(lvp != NULLVP);
1366 	if (uio->uio_offset == 0)
1367 		unsp->uns_readdir_status = 0;
1368 
1369 	if (unsp->uns_readdir_status == 0) {
1370 		/* read upper */
1371 		error = VOP_READDIR(uvp, uio, ap->a_cred, &eofflag,
1372 				    ap->a_cookies, ap->a_ncookies);
1373 
1374 		if (error != 0 || eofflag == 0)
1375 			goto unionfs_readdir_exit;
1376 		unsp->uns_readdir_status = 1;
1377 
1378 		/*
1379 		 * ufs(and other fs) needs size of uio_resid larger than
1380 		 * DIRBLKSIZ.
1381 		 * size of DIRBLKSIZ equals DEV_BSIZE.
1382 		 * (see: ufs/ufs/ufs_vnops.c ufs_readdir func , ufs/ufs/dir.h)
1383 		 */
1384 		if (uio->uio_resid <= (uio->uio_resid & (DEV_BSIZE -1)))
1385 			goto unionfs_readdir_exit;
1386 
1387 		/*
1388 		 * backup cookies
1389 		 * It prepares to readdir in lower.
1390 		 */
1391 		if (ap->a_ncookies != NULL) {
1392 			ncookies_bk = *(ap->a_ncookies);
1393 			*(ap->a_ncookies) = 0;
1394 		}
1395 		if (ap->a_cookies != NULL) {
1396 			cookies_bk = *(ap->a_cookies);
1397 			*(ap->a_cookies) = NULL;
1398 		}
1399 	}
1400 
1401 	/* initialize for readdir in lower */
1402 	if (unsp->uns_readdir_status == 1) {
1403 		unsp->uns_readdir_status = 2;
1404 		uio->uio_offset = 0;
1405 	}
1406 
1407 	if (lvp == NULLVP) {
1408 		error = EBADF;
1409 		goto unionfs_readdir_exit;
1410 	}
1411 	/* read lower */
1412 	error = VOP_READDIR(lvp, uio, ap->a_cred, ap->a_eofflag,
1413 			    ap->a_cookies, ap->a_ncookies);
1414 
1415 	if (cookies_bk != NULL) {
1416 		/* merge cookies */
1417 		int		size;
1418 		off_t         *newcookies, *pos;
1419 
1420 		size = *(ap->a_ncookies) + ncookies_bk;
1421 		newcookies = (off_t *) malloc(size * sizeof(off_t),
1422 		    M_TEMP, M_WAITOK);
1423 		pos = newcookies;
1424 
1425 		memcpy(pos, cookies_bk, ncookies_bk * sizeof(off_t));
1426 		pos += ncookies_bk * sizeof(off_t);
1427 		memcpy(pos, *(ap->a_cookies), *(ap->a_ncookies) * sizeof(off_t));
1428 		free(cookies_bk, M_TEMP);
1429 		free(*(ap->a_cookies), M_TEMP);
1430 		*(ap->a_ncookies) = size;
1431 		*(ap->a_cookies) = newcookies;
1432 	}
1433 
1434 unionfs_readdir_exit:
1435 	if (error != 0 && ap->a_eofflag != NULL)
1436 		*(ap->a_eofflag) = 1;
1437 
1438 	UNIONFS_INTERNAL_DEBUG("unionfs_readdir: leave (%d)\n", error);
1439 
1440 	return (error);
1441 }
1442 
1443 static int
1444 unionfs_readlink(void *v)
1445 {
1446 	struct vop_readlink_args *ap = v;
1447 	int error;
1448 	struct unionfs_node *unp;
1449 	struct vnode   *vp;
1450 
1451 	UNIONFS_INTERNAL_DEBUG("unionfs_readlink: enter\n");
1452 
1453 	unp = VTOUNIONFS(ap->a_vp);
1454 	vp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
1455 
1456 	error = VOP_READLINK(vp, ap->a_uio, ap->a_cred);
1457 
1458 	UNIONFS_INTERNAL_DEBUG("unionfs_readlink: leave (%d)\n", error);
1459 
1460 	return (error);
1461 }
1462 
1463 static int
1464 unionfs_inactive(void *v)
1465 {
1466 	struct vop_inactive_args *ap = v;
1467 	*ap->a_recycle = true;
1468 	VOP_UNLOCK(ap->a_vp);
1469 	return (0);
1470 }
1471 
1472 static int
1473 unionfs_reclaim(void *v)
1474 {
1475 	struct vop_reclaim_args *ap = v;
1476 
1477 	/* UNIONFS_INTERNAL_DEBUG("unionfs_reclaim: enter\n"); */
1478 
1479 	unionfs_noderem(ap->a_vp);
1480 
1481 	/* UNIONFS_INTERNAL_DEBUG("unionfs_reclaim: leave\n"); */
1482 
1483 	return (0);
1484 }
1485 
1486 static int
1487 unionfs_print(void *v)
1488 {
1489 	struct vop_print_args *ap = v;
1490 	struct unionfs_node *unp;
1491 	/* struct unionfs_node_status *unsp; */
1492 
1493 	unp = VTOUNIONFS(ap->a_vp);
1494 	/* unionfs_get_node_status(unp, &unsp); */
1495 
1496 	printf("unionfs_vp=%p, uppervp=%p, lowervp=%p\n",
1497 	    ap->a_vp, unp->un_uppervp, unp->un_lowervp);
1498 	/*
1499 	printf("unionfs opencnt: uppervp=%d, lowervp=%d\n",
1500 	    unsp->uns_upper_opencnt, unsp->uns_lower_opencnt);
1501 	*/
1502 
1503 	if (unp->un_uppervp != NULLVP)
1504 		vprint("unionfs: upper", unp->un_uppervp);
1505 	if (unp->un_lowervp != NULLVP)
1506 		vprint("unionfs: lower", unp->un_lowervp);
1507 
1508 	return (0);
1509 }
1510 
1511 static int
1512 unionfs_lock(void *v)
1513 {
1514 	struct vop_lock_args *ap = v;
1515 	int		error;
1516 	int		flags;
1517 	struct vnode   *lvp;
1518 	struct vnode   *uvp;
1519 	struct unionfs_node *unp;
1520 
1521 	unp = VTOUNIONFS(ap->a_vp);
1522 	lvp = unp->un_lowervp;
1523 	uvp = unp->un_uppervp;
1524 	flags = ap->a_flags;
1525 	error = 0;
1526 
1527 	if (lvp != NULLVP) {
1528 		error = VOP_LOCK(lvp, flags);
1529 	}
1530 	if (error == 0 && uvp != NULLVP) {
1531 		error = VOP_LOCK(uvp, flags);
1532 		if (error != 0) {
1533 			VOP_UNLOCK(lvp);
1534 		}
1535 	}
1536 
1537 	return error;
1538 }
1539 
1540 static int
1541 unionfs_unlock(void *v)
1542 {
1543 	struct vop_unlock_args *ap = v;
1544 	int		error;
1545 	struct vnode   *lvp;
1546 	struct vnode   *uvp;
1547 	struct unionfs_node *unp;
1548 
1549 	unp = VTOUNIONFS(ap->a_vp);
1550 	lvp = unp->un_lowervp;
1551 	uvp = unp->un_uppervp;
1552 	error = 0;
1553 
1554 	if (lvp != NULLVP) {
1555 		error = VOP_UNLOCK(lvp);
1556 	}
1557 	if (error == 0 && uvp != NULLVP) {
1558 		error = VOP_UNLOCK(uvp);
1559 	}
1560 
1561 	return error;
1562 }
1563 
1564 static int
1565 unionfs_pathconf(void *v)
1566 {
1567 	struct vop_pathconf_args *ap = v;
1568 	struct unionfs_node *unp;
1569 	struct vnode   *vp;
1570 
1571 	unp = VTOUNIONFS(ap->a_vp);
1572 	vp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
1573 
1574 	return (VOP_PATHCONF(vp, ap->a_name, ap->a_retval));
1575 }
1576 
1577 static int
1578 unionfs_advlock(void *v)
1579 {
1580 	struct vop_advlock_args *ap = v;
1581 	int error;
1582 	struct unionfs_node *unp;
1583 	struct unionfs_node_status *unsp;
1584 	struct vnode   *vp;
1585 	struct vnode   *uvp;
1586 	kauth_cred_t	cred;
1587 
1588 	UNIONFS_INTERNAL_DEBUG("unionfs_advlock: enter\n");
1589 
1590 	vp = ap->a_vp;
1591 	cred = kauth_cred_get();
1592 
1593 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1594 
1595 	unp = VTOUNIONFS(ap->a_vp);
1596 	uvp = unp->un_uppervp;
1597 
1598 	if (uvp == NULLVP) {
1599 		error = unionfs_copyfile(unp, 1, cred);
1600 		if (error != 0)
1601 			goto unionfs_advlock_abort;
1602 		uvp = unp->un_uppervp;
1603 
1604 		unionfs_get_node_status(unp, &unsp);
1605 		if (unsp->uns_lower_opencnt > 0) {
1606 			/* try reopen the vnode */
1607 			error = VOP_OPEN(uvp, unsp->uns_lower_openmode, cred);
1608 			if (error)
1609 				goto unionfs_advlock_abort;
1610 			unsp->uns_upper_opencnt++;
1611 			VOP_CLOSE(unp->un_lowervp, unsp->uns_lower_openmode, cred);
1612 			unsp->uns_lower_opencnt--;
1613 		} else
1614 			unionfs_tryrem_node_status(unp, unsp);
1615 	}
1616 
1617 	VOP_UNLOCK(vp);
1618 
1619 	error = VOP_ADVLOCK(uvp, ap->a_id, ap->a_op, ap->a_fl, ap->a_flags);
1620 
1621 	UNIONFS_INTERNAL_DEBUG("unionfs_advlock: leave (%d)\n", error);
1622 
1623 	return error;
1624 
1625 unionfs_advlock_abort:
1626 	VOP_UNLOCK(vp);
1627 
1628 	UNIONFS_INTERNAL_DEBUG("unionfs_advlock: leave (%d)\n", error);
1629 
1630 	return error;
1631 }
1632 
1633 static int
1634 unionfs_strategy(void *v)
1635 {
1636 	struct vop_strategy_args *ap = v;
1637 	struct unionfs_node *unp;
1638 	struct vnode   *vp;
1639 
1640 	unp = VTOUNIONFS(ap->a_vp);
1641 	vp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
1642 
1643 #ifdef DIAGNOSTIC
1644 	if (vp == NULLVP)
1645 		panic("unionfs_strategy: nullvp");
1646 	if ((ap->a_bp->b_flags & B_READ) == 0 && vp == unp->un_lowervp)
1647 		panic("unionfs_strategy: writing to lowervp");
1648 #endif
1649 
1650 	return (VOP_STRATEGY(vp, ap->a_bp));
1651 }
1652 
1653 static int
1654 unionfs_kqfilter(void *v)
1655 {
1656 	struct vop_kqfilter_args *ap = v;
1657 	struct unionfs_node *unp;
1658 	struct vnode   *tvp;
1659 
1660 	unp = VTOUNIONFS(ap->a_vp);
1661 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
1662 
1663 	return VOP_KQFILTER(tvp, ap->a_kn);
1664 }
1665 
1666 static int
1667 unionfs_bmap(void *v)
1668 {
1669 	struct vop_bmap_args *ap = v;
1670 	struct unionfs_node *unp;
1671 	struct vnode   *tvp;
1672 
1673 	unp = VTOUNIONFS(ap->a_vp);
1674 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
1675 
1676 	return VOP_BMAP(tvp, ap->a_bn, ap->a_vpp, ap->a_bnp, ap->a_runp);
1677 }
1678 
1679 static int
1680 unionfs_mmap(void *v)
1681 {
1682 	struct vop_mmap_args *ap = v;
1683 	struct unionfs_node *unp;
1684 	struct vnode   *tvp;
1685 
1686 	unp = VTOUNIONFS(ap->a_vp);
1687 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
1688 
1689 	return VOP_MMAP(tvp, ap->a_prot, ap->a_cred);
1690 }
1691 
1692 static int
1693 unionfs_abortop(void *v)
1694 {
1695 	struct vop_abortop_args *ap = v;
1696 	struct unionfs_node *unp;
1697 	struct vnode   *tvp;
1698 
1699 	unp = VTOUNIONFS(ap->a_dvp);
1700 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
1701 
1702 	return VOP_ABORTOP(tvp, ap->a_cnp);
1703 }
1704 
1705 static int
1706 unionfs_islocked(void *v)
1707 {
1708 	struct vop_islocked_args *ap = v;
1709 	struct unionfs_node *unp;
1710 	struct vnode   *tvp;
1711 
1712 	unp = VTOUNIONFS(ap->a_vp);
1713 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
1714 
1715 	return VOP_ISLOCKED(tvp);
1716 }
1717 
1718 static int
1719 unionfs_seek(void *v)
1720 {
1721 	struct vop_seek_args *ap = v;
1722 	struct unionfs_node *unp;
1723 	struct vnode   *tvp;
1724 
1725 	unp = VTOUNIONFS(ap->a_vp);
1726 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
1727 
1728 	return VOP_SEEK(tvp, ap->a_oldoff, ap->a_newoff, ap->a_cred);
1729 }
1730 
1731 static int
1732 unionfs_putpages(void *v)
1733 {
1734 	struct vop_putpages_args /* {
1735 		struct vnode *a_vp;
1736 		voff_t a_offlo;
1737 		voff_t a_offhi;
1738 		int a_flags;
1739 	} */ *ap = v;
1740 	struct vnode *vp = ap->a_vp, *tvp;
1741 	struct unionfs_node *unp;
1742 
1743 	KASSERT(mutex_owned(vp->v_interlock));
1744 
1745 	unp = VTOUNIONFS(vp);
1746 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
1747 	KASSERT(tvp->v_interlock == vp->v_interlock);
1748 
1749 	if (ap->a_flags & PGO_RECLAIM) {
1750 		mutex_exit(vp->v_interlock);
1751 		return 0;
1752 	}
1753 	return VOP_PUTPAGES(tvp, ap->a_offlo, ap->a_offhi, ap->a_flags);
1754 }
1755 
1756 static int
1757 unionfs_getpages(void *v)
1758 {
1759 	struct vop_getpages_args /* {
1760 		struct vnode *a_vp;
1761 		voff_t a_offset;
1762 		struct vm_page **a_m;
1763 		int *a_count;
1764 		int a_centeridx;
1765 		vm_prot_t a_access_type;
1766 		int a_advice;
1767 		int a_flags;
1768 	} */ *ap = v;
1769 	struct vnode *vp = ap->a_vp, *tvp;
1770 	struct unionfs_node *unp;
1771 
1772 	KASSERT(mutex_owned(vp->v_interlock));
1773 
1774 	unp = VTOUNIONFS(vp);
1775 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
1776 	KASSERT(tvp->v_interlock == vp->v_interlock);
1777 
1778 	if (ap->a_flags & PGO_LOCKED) {
1779 		return EBUSY;
1780 	}
1781 	return VOP_GETPAGES(tvp, ap->a_offset, ap->a_m, ap->a_count,
1782 	    ap->a_centeridx, ap->a_access_type, ap->a_advice, ap->a_flags);
1783 }
1784 
1785 static int
1786 unionfs_revoke(void *v)
1787 {
1788 	struct vop_revoke_args *ap = v;
1789 	struct unionfs_node *unp;
1790 	struct vnode   *tvp;
1791 	int error;
1792 
1793 	unp = VTOUNIONFS(ap->a_vp);
1794 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
1795 
1796 	error = VOP_REVOKE(tvp, ap->a_flags);
1797 	if (error == 0) {
1798 		vgone(ap->a_vp);	/* ??? */
1799 	}
1800 	return error;
1801 }
1802 
1803 /*
1804  * Global vfs data structures
1805  */
1806 int (**unionfs_vnodeop_p)(void *);
1807 const struct vnodeopv_entry_desc unionfs_vnodeop_entries[] = {
1808 	{ &vop_default_desc, vn_default_error },
1809 	{ &vop_lookup_desc, unionfs_lookup },		/* lookup */
1810 	{ &vop_create_desc, unionfs_create },		/* create */
1811 	{ &vop_whiteout_desc, unionfs_whiteout },	/* whiteout */
1812 	{ &vop_mknod_desc, unionfs_mknod },		/* mknod */
1813 	{ &vop_open_desc, unionfs_open },		/* open */
1814 	{ &vop_close_desc, unionfs_close },		/* close */
1815 	{ &vop_access_desc, unionfs_access },		/* access */
1816 	{ &vop_getattr_desc, unionfs_getattr },		/* getattr */
1817 	{ &vop_setattr_desc, unionfs_setattr },		/* setattr */
1818 	{ &vop_read_desc, unionfs_read },		/* read */
1819 	{ &vop_write_desc, unionfs_write },		/* write */
1820 	{ &vop_ioctl_desc, unionfs_ioctl },		/* ioctl */
1821 	{ &vop_poll_desc, unionfs_poll },		/* select */
1822 	{ &vop_revoke_desc, unionfs_revoke },		/* revoke */
1823 	{ &vop_mmap_desc, unionfs_mmap },		/* mmap */
1824 	{ &vop_fsync_desc, unionfs_fsync },		/* fsync */
1825 	{ &vop_seek_desc, unionfs_seek },		/* seek */
1826 	{ &vop_remove_desc, unionfs_remove },		/* remove */
1827 	{ &vop_link_desc, unionfs_link },		/* link */
1828 	{ &vop_rename_desc, unionfs_rename },		/* rename */
1829 	{ &vop_mkdir_desc, unionfs_mkdir },		/* mkdir */
1830 	{ &vop_rmdir_desc, unionfs_rmdir },		/* rmdir */
1831 	{ &vop_symlink_desc, unionfs_symlink },		/* symlink */
1832 	{ &vop_readdir_desc, unionfs_readdir },		/* readdir */
1833 	{ &vop_readlink_desc, unionfs_readlink },	/* readlink */
1834 	{ &vop_abortop_desc, unionfs_abortop },		/* abortop */
1835 	{ &vop_inactive_desc, unionfs_inactive },	/* inactive */
1836 	{ &vop_reclaim_desc, unionfs_reclaim },		/* reclaim */
1837 	{ &vop_lock_desc, unionfs_lock },		/* lock */
1838 	{ &vop_unlock_desc, unionfs_unlock },		/* unlock */
1839 	{ &vop_bmap_desc, unionfs_bmap },		/* bmap */
1840 	{ &vop_strategy_desc, unionfs_strategy },	/* strategy */
1841 	{ &vop_print_desc, unionfs_print },		/* print */
1842 	{ &vop_islocked_desc, unionfs_islocked },	/* islocked */
1843 	{ &vop_pathconf_desc, unionfs_pathconf },	/* pathconf */
1844 	{ &vop_advlock_desc, unionfs_advlock },		/* advlock */
1845 	{ &vop_getpages_desc, unionfs_getpages },	/* getpages */
1846 	{ &vop_putpages_desc, unionfs_putpages },	/* putpages */
1847 	{ &vop_kqfilter_desc, unionfs_kqfilter },	/* kqfilter */
1848 #ifdef notdef
1849 	{ &vop_bwrite_desc, unionfs_bwrite },		/* bwrite */
1850 #endif
1851 	{ NULL, NULL }
1852 };
1853 const struct vnodeopv_desc unionfs_vnodeop_opv_desc =
1854 	{ &unionfs_vnodeop_p, unionfs_vnodeop_entries };
1855