xref: /freebsd/sys/fs/unionfs/union_vnops.c (revision 55224280e2f20474f83001cbc402b21fba8f1c4b)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1992, 1993, 1994, 1995 Jan-Simon Pendry.
5  * Copyright (c) 1992, 1993, 1994, 1995
6  *      The Regents of the University of California.
7  * Copyright (c) 2005, 2006, 2012 Masanori Ozawa <ozawa@ongs.co.jp>, ONGS Inc.
8  * Copyright (c) 2006, 2012 Daichi Goto <daichi@freebsd.org>
9  * All rights reserved.
10  *
11  * This code is derived from software contributed to Berkeley by
12  * Jan-Simon Pendry.
13  *
14  * Redistribution and use in source and binary forms, with or without
15  * modification, are permitted provided that the following conditions
16  * are met:
17  * 1. Redistributions of source code must retain the above copyright
18  *    notice, this list of conditions and the following disclaimer.
19  * 2. Redistributions in binary form must reproduce the above copyright
20  *    notice, this list of conditions and the following disclaimer in the
21  *    documentation and/or other materials provided with the distribution.
22  * 3. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)union_vnops.c	8.32 (Berkeley) 6/23/95
39  * $FreeBSD$
40  *
41  */
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/conf.h>
46 #include <sys/kernel.h>
47 #include <sys/lock.h>
48 #include <sys/malloc.h>
49 #include <sys/mount.h>
50 #include <sys/mutex.h>
51 #include <sys/namei.h>
52 #include <sys/sysctl.h>
53 #include <sys/vnode.h>
54 #include <sys/kdb.h>
55 #include <sys/fcntl.h>
56 #include <sys/stat.h>
57 #include <sys/dirent.h>
58 #include <sys/proc.h>
59 #include <sys/bio.h>
60 #include <sys/buf.h>
61 
62 #include <fs/unionfs/union.h>
63 
64 #include <machine/atomic.h>
65 
66 #include <vm/vm.h>
67 #include <vm/vm_extern.h>
68 #include <vm/vm_object.h>
69 #include <vm/vnode_pager.h>
70 
71 #if 0
72 #define UNIONFS_INTERNAL_DEBUG(msg, args...)    printf(msg, ## args)
73 #define UNIONFS_IDBG_RENAME
74 #else
75 #define UNIONFS_INTERNAL_DEBUG(msg, args...)
76 #endif
77 
78 #define KASSERT_UNIONFS_VNODE(vp) \
79 	KASSERT(((vp)->v_op == &unionfs_vnodeops), \
80 	    ("unionfs: it is not unionfs-vnode"))
81 
82 static int
83 unionfs_lookup(struct vop_cachedlookup_args *ap)
84 {
85 	struct unionfs_node *dunp;
86 	struct vnode   *dvp, *udvp, *ldvp, *vp, *uvp, *lvp, *dtmpvp;
87 	struct vattr	va;
88 	struct componentname *cnp;
89 	struct thread  *td;
90 	u_long		nameiop;
91 	u_long		cnflags, cnflagsbk;
92 	int		iswhiteout;
93 	int		lockflag;
94 	int		error , uerror, lerror;
95 
96 	iswhiteout = 0;
97 	lockflag = 0;
98 	error = uerror = lerror = ENOENT;
99 	cnp = ap->a_cnp;
100 	nameiop = cnp->cn_nameiop;
101 	cnflags = cnp->cn_flags;
102 	dvp = ap->a_dvp;
103 	dunp = VTOUNIONFS(dvp);
104 	udvp = dunp->un_uppervp;
105 	ldvp = dunp->un_lowervp;
106 	vp = uvp = lvp = NULLVP;
107 	td = curthread;
108 	*(ap->a_vpp) = NULLVP;
109 
110 	UNIONFS_INTERNAL_DEBUG(
111 	    "unionfs_lookup: enter: nameiop=%ld, flags=%lx, path=%s\n",
112 	    nameiop, cnflags, cnp->cn_nameptr);
113 
114 	if (dvp->v_type != VDIR)
115 		return (ENOTDIR);
116 
117 	/*
118 	 * If read-only and op is not LOOKUP, will return EROFS.
119 	 */
120 	if ((cnflags & ISLASTCN) &&
121 	    (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
122 	    LOOKUP != nameiop)
123 		return (EROFS);
124 
125 	/*
126 	 * lookup dotdot
127 	 */
128 	if (cnflags & ISDOTDOT) {
129 		if (LOOKUP != nameiop && udvp == NULLVP)
130 			return (EROFS);
131 
132 		if (udvp != NULLVP) {
133 			dtmpvp = udvp;
134 			if (ldvp != NULLVP)
135 				VOP_UNLOCK(ldvp);
136 		}
137 		else
138 			dtmpvp = ldvp;
139 
140 		error = VOP_LOOKUP(dtmpvp, &vp, cnp);
141 
142 		if (dtmpvp == udvp && ldvp != NULLVP) {
143 			VOP_UNLOCK(udvp);
144 			vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
145 		}
146 
147 		if (error == 0) {
148 			/*
149 			 * Exchange lock and reference from vp to
150 			 * dunp->un_dvp. vp is upper/lower vnode, but it
151 			 * will need to return the unionfs vnode.
152 			 */
153 			if (nameiop == DELETE  || nameiop == RENAME ||
154 			    (cnp->cn_lkflags & LK_TYPE_MASK))
155 				VOP_UNLOCK(vp);
156 			vrele(vp);
157 
158 			VOP_UNLOCK(dvp);
159 			*(ap->a_vpp) = dunp->un_dvp;
160 			vref(dunp->un_dvp);
161 
162 			if (nameiop == DELETE || nameiop == RENAME)
163 				vn_lock(dunp->un_dvp, LK_EXCLUSIVE | LK_RETRY);
164 			else if (cnp->cn_lkflags & LK_TYPE_MASK)
165 				vn_lock(dunp->un_dvp, cnp->cn_lkflags |
166 				    LK_RETRY);
167 
168 			vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
169 		} else if (error == ENOENT && (cnflags & MAKEENTRY) != 0)
170 			cache_enter(dvp, NULLVP, cnp);
171 
172 		goto unionfs_lookup_return;
173 	}
174 
175 	/*
176 	 * lookup upper layer
177 	 */
178 	if (udvp != NULLVP) {
179 		uerror = VOP_LOOKUP(udvp, &uvp, cnp);
180 
181 		if (uerror == 0) {
182 			if (udvp == uvp) {	/* is dot */
183 				vrele(uvp);
184 				*(ap->a_vpp) = dvp;
185 				vref(dvp);
186 
187 				error = uerror;
188 				goto unionfs_lookup_return;
189 			}
190 			if (nameiop == DELETE || nameiop == RENAME ||
191 			    (cnp->cn_lkflags & LK_TYPE_MASK))
192 				VOP_UNLOCK(uvp);
193 		}
194 
195 		/* check whiteout */
196 		if (uerror == ENOENT || uerror == EJUSTRETURN)
197 			if (cnp->cn_flags & ISWHITEOUT)
198 				iswhiteout = 1;	/* don't lookup lower */
199 		if (iswhiteout == 0 && ldvp != NULLVP)
200 			if (!VOP_GETATTR(udvp, &va, cnp->cn_cred) &&
201 			    (va.va_flags & OPAQUE))
202 				iswhiteout = 1;	/* don't lookup lower */
203 #if 0
204 		UNIONFS_INTERNAL_DEBUG(
205 		    "unionfs_lookup: debug: whiteout=%d, path=%s\n",
206 		    iswhiteout, cnp->cn_nameptr);
207 #endif
208 	}
209 
210 	/*
211 	 * lookup lower layer
212 	 */
213 	if (ldvp != NULLVP && !(cnflags & DOWHITEOUT) && iswhiteout == 0) {
214 		/* always op is LOOKUP */
215 		cnp->cn_nameiop = LOOKUP;
216 		cnflagsbk = cnp->cn_flags;
217 		cnp->cn_flags = cnflags;
218 
219 		lerror = VOP_LOOKUP(ldvp, &lvp, cnp);
220 
221 		cnp->cn_nameiop = nameiop;
222 		if (udvp != NULLVP && (uerror == 0 || uerror == EJUSTRETURN))
223 			cnp->cn_flags = cnflagsbk;
224 
225 		if (lerror == 0) {
226 			if (ldvp == lvp) {	/* is dot */
227 				if (uvp != NULLVP)
228 					vrele(uvp);	/* no need? */
229 				vrele(lvp);
230 				*(ap->a_vpp) = dvp;
231 				vref(dvp);
232 
233 				UNIONFS_INTERNAL_DEBUG(
234 				    "unionfs_lookup: leave (%d)\n", lerror);
235 
236 				return (lerror);
237 			}
238 			if (cnp->cn_lkflags & LK_TYPE_MASK)
239 				VOP_UNLOCK(lvp);
240 		}
241 	}
242 
243 	/*
244 	 * check lookup result
245 	 */
246 	if (uvp == NULLVP && lvp == NULLVP) {
247 		error = (udvp != NULLVP ? uerror : lerror);
248 		goto unionfs_lookup_return;
249 	}
250 
251 	/*
252 	 * check vnode type
253 	 */
254 	if (uvp != NULLVP && lvp != NULLVP && uvp->v_type != lvp->v_type) {
255 		vrele(lvp);
256 		lvp = NULLVP;
257 	}
258 
259 	/*
260 	 * check shadow dir
261 	 */
262 	if (uerror != 0 && uerror != EJUSTRETURN && udvp != NULLVP &&
263 	    lerror == 0 && lvp != NULLVP && lvp->v_type == VDIR &&
264 	    !(dvp->v_mount->mnt_flag & MNT_RDONLY) &&
265 	    (1 < cnp->cn_namelen || '.' != *(cnp->cn_nameptr))) {
266 		/* get unionfs vnode in order to create a new shadow dir. */
267 		error = unionfs_nodeget(dvp->v_mount, NULLVP, lvp, dvp, &vp,
268 		    cnp);
269 		if (error != 0)
270 			goto unionfs_lookup_cleanup;
271 
272 		if (LK_SHARED == (cnp->cn_lkflags & LK_TYPE_MASK))
273 			VOP_UNLOCK(vp);
274 		if (LK_EXCLUSIVE != VOP_ISLOCKED(vp)) {
275 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
276 			lockflag = 1;
277 		}
278 		error = unionfs_mkshadowdir(MOUNTTOUNIONFSMOUNT(dvp->v_mount),
279 		    udvp, VTOUNIONFS(vp), cnp, td);
280 		if (lockflag != 0)
281 			VOP_UNLOCK(vp);
282 		if (error != 0) {
283 			UNIONFSDEBUG(
284 			    "unionfs_lookup: Unable to create shadow dir.");
285 			if ((cnp->cn_lkflags & LK_TYPE_MASK) == LK_EXCLUSIVE)
286 				vput(vp);
287 			else
288 				vrele(vp);
289 			goto unionfs_lookup_cleanup;
290 		}
291 		if ((cnp->cn_lkflags & LK_TYPE_MASK) == LK_SHARED)
292 			vn_lock(vp, LK_SHARED | LK_RETRY);
293 	}
294 	/*
295 	 * get unionfs vnode.
296 	 */
297 	else {
298 		if (uvp != NULLVP)
299 			error = uerror;
300 		else
301 			error = lerror;
302 		if (error != 0)
303 			goto unionfs_lookup_cleanup;
304 		/*
305 		 * get socket vnode.
306 		 */
307 		if (uvp != NULLVP && uvp->v_type == VSOCK) {
308 			vp = uvp;
309 			vref(vp);
310 			if (cnp->cn_lkflags & LK_TYPE_MASK)
311 				vn_lock(vp, cnp->cn_lkflags | LK_RETRY);
312 		}
313 		else if (lvp != NULLVP && lvp->v_type == VSOCK) {
314 			vp = lvp;
315 			vref(vp);
316 			if (cnp->cn_lkflags & LK_TYPE_MASK)
317 				vn_lock(vp, cnp->cn_lkflags | LK_RETRY);
318 		}
319 		/*
320 		 * get unionfs vnode.
321 		 */
322 		else
323 			error = unionfs_nodeget(dvp->v_mount, uvp, lvp,
324 			    dvp, &vp, cnp);
325 		if (error != 0) {
326 			UNIONFSDEBUG(
327 			    "unionfs_lookup: Unable to create unionfs vnode.");
328 			goto unionfs_lookup_cleanup;
329 		}
330 		if ((nameiop == DELETE || nameiop == RENAME) &&
331 		    (cnp->cn_lkflags & LK_TYPE_MASK) == 0)
332 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
333 	}
334 
335 	*(ap->a_vpp) = vp;
336 
337 	if ((cnflags & MAKEENTRY) && vp->v_type != VSOCK)
338 		cache_enter(dvp, vp, cnp);
339 
340 unionfs_lookup_cleanup:
341 	if (uvp != NULLVP)
342 		vrele(uvp);
343 	if (lvp != NULLVP)
344 		vrele(lvp);
345 
346 	if (error == ENOENT && (cnflags & MAKEENTRY) != 0)
347 		cache_enter(dvp, NULLVP, cnp);
348 
349 unionfs_lookup_return:
350 
351 	/* Ensure subsequent vnops will get a valid pathname buffer. */
352 	if (nameiop != LOOKUP && (error == 0 || error == EJUSTRETURN))
353 		cnp->cn_flags |= SAVENAME;
354 
355 	UNIONFS_INTERNAL_DEBUG("unionfs_lookup: leave (%d)\n", error);
356 
357 	return (error);
358 }
359 
360 static int
361 unionfs_create(struct vop_create_args *ap)
362 {
363 	struct unionfs_node *dunp;
364 	struct componentname *cnp;
365 	struct vnode   *udvp;
366 	struct vnode   *vp;
367 	int		error;
368 
369 	UNIONFS_INTERNAL_DEBUG("unionfs_create: enter\n");
370 
371 	KASSERT_UNIONFS_VNODE(ap->a_dvp);
372 
373 	dunp = VTOUNIONFS(ap->a_dvp);
374 	cnp = ap->a_cnp;
375 	udvp = dunp->un_uppervp;
376 	error = EROFS;
377 
378 	if (udvp != NULLVP) {
379 		error = VOP_CREATE(udvp, &vp, cnp, ap->a_vap);
380 		if (error != 0)
381 			goto unionfs_create_abort;
382 
383 		if (vp->v_type == VSOCK)
384 			*(ap->a_vpp) = vp;
385 		else {
386 			VOP_UNLOCK(vp);
387 			error = unionfs_nodeget(ap->a_dvp->v_mount, vp, NULLVP,
388 			    ap->a_dvp, ap->a_vpp, cnp);
389 			vrele(vp);
390 		}
391 	}
392 
393 unionfs_create_abort:
394 	UNIONFS_INTERNAL_DEBUG("unionfs_create: leave (%d)\n", error);
395 
396 	return (error);
397 }
398 
399 static int
400 unionfs_whiteout(struct vop_whiteout_args *ap)
401 {
402 	struct unionfs_node *dunp;
403 	struct componentname *cnp;
404 	struct vnode   *udvp;
405 	int		error;
406 
407 	UNIONFS_INTERNAL_DEBUG("unionfs_whiteout: enter\n");
408 
409 	KASSERT_UNIONFS_VNODE(ap->a_dvp);
410 
411 	dunp = VTOUNIONFS(ap->a_dvp);
412 	cnp = ap->a_cnp;
413 	udvp = dunp->un_uppervp;
414 	error = EOPNOTSUPP;
415 
416 	if (udvp != NULLVP) {
417 		switch (ap->a_flags) {
418 		case CREATE:
419 		case DELETE:
420 		case LOOKUP:
421 			error = VOP_WHITEOUT(udvp, cnp, ap->a_flags);
422 			break;
423 		default:
424 			error = EINVAL;
425 			break;
426 		}
427 	}
428 
429 	UNIONFS_INTERNAL_DEBUG("unionfs_whiteout: leave (%d)\n", error);
430 
431 	return (error);
432 }
433 
434 static int
435 unionfs_mknod(struct vop_mknod_args *ap)
436 {
437 	struct unionfs_node *dunp;
438 	struct componentname *cnp;
439 	struct vnode   *udvp;
440 	struct vnode   *vp;
441 	int		error;
442 
443 	UNIONFS_INTERNAL_DEBUG("unionfs_mknod: enter\n");
444 
445 	KASSERT_UNIONFS_VNODE(ap->a_dvp);
446 
447 	dunp = VTOUNIONFS(ap->a_dvp);
448 	cnp = ap->a_cnp;
449 	udvp = dunp->un_uppervp;
450 	error = EROFS;
451 
452 	if (udvp != NULLVP) {
453 		error = VOP_MKNOD(udvp, &vp, cnp, ap->a_vap);
454 		if (error != 0)
455 			goto unionfs_mknod_abort;
456 
457 		if (vp->v_type == VSOCK)
458 			*(ap->a_vpp) = vp;
459 		else {
460 			VOP_UNLOCK(vp);
461 			error = unionfs_nodeget(ap->a_dvp->v_mount, vp, NULLVP,
462 			    ap->a_dvp, ap->a_vpp, cnp);
463 			vrele(vp);
464 		}
465 	}
466 
467 unionfs_mknod_abort:
468 	UNIONFS_INTERNAL_DEBUG("unionfs_mknod: leave (%d)\n", error);
469 
470 	return (error);
471 }
472 
473 static int
474 unionfs_open(struct vop_open_args *ap)
475 {
476 	struct unionfs_node *unp;
477 	struct unionfs_node_status *unsp;
478 	struct vnode   *uvp;
479 	struct vnode   *lvp;
480 	struct vnode   *targetvp;
481 	struct ucred   *cred;
482 	struct thread  *td;
483 	int		error;
484 
485 	UNIONFS_INTERNAL_DEBUG("unionfs_open: enter\n");
486 
487 	KASSERT_UNIONFS_VNODE(ap->a_vp);
488 
489 	error = 0;
490 	unp = VTOUNIONFS(ap->a_vp);
491 	uvp = unp->un_uppervp;
492 	lvp = unp->un_lowervp;
493 	targetvp = NULLVP;
494 	cred = ap->a_cred;
495 	td = ap->a_td;
496 
497 	unionfs_get_node_status(unp, td, &unsp);
498 
499 	if (unsp->uns_lower_opencnt > 0 || unsp->uns_upper_opencnt > 0) {
500 		/* vnode is already opend. */
501 		if (unsp->uns_upper_opencnt > 0)
502 			targetvp = uvp;
503 		else
504 			targetvp = lvp;
505 
506 		if (targetvp == lvp &&
507 		    (ap->a_mode & FWRITE) && lvp->v_type == VREG)
508 			targetvp = NULLVP;
509 	}
510 	if (targetvp == NULLVP) {
511 		if (uvp == NULLVP) {
512 			if ((ap->a_mode & FWRITE) && lvp->v_type == VREG) {
513 				error = unionfs_copyfile(unp,
514 				    !(ap->a_mode & O_TRUNC), cred, td);
515 				if (error != 0)
516 					goto unionfs_open_abort;
517 				targetvp = uvp = unp->un_uppervp;
518 			} else
519 				targetvp = lvp;
520 		} else
521 			targetvp = uvp;
522 	}
523 
524 	error = VOP_OPEN(targetvp, ap->a_mode, cred, td, ap->a_fp);
525 	if (error == 0) {
526 		if (targetvp == uvp) {
527 			if (uvp->v_type == VDIR && lvp != NULLVP &&
528 			    unsp->uns_lower_opencnt <= 0) {
529 				/* open lower for readdir */
530 				error = VOP_OPEN(lvp, FREAD, cred, td, NULL);
531 				if (error != 0) {
532 					VOP_CLOSE(uvp, ap->a_mode, cred, td);
533 					goto unionfs_open_abort;
534 				}
535 				unsp->uns_node_flag |= UNS_OPENL_4_READDIR;
536 				unsp->uns_lower_opencnt++;
537 			}
538 			unsp->uns_upper_opencnt++;
539 		} else {
540 			unsp->uns_lower_opencnt++;
541 			unsp->uns_lower_openmode = ap->a_mode;
542 		}
543 		ap->a_vp->v_object = targetvp->v_object;
544 	}
545 
546 unionfs_open_abort:
547 	if (error != 0)
548 		unionfs_tryrem_node_status(unp, unsp);
549 
550 	UNIONFS_INTERNAL_DEBUG("unionfs_open: leave (%d)\n", error);
551 
552 	return (error);
553 }
554 
555 static int
556 unionfs_close(struct vop_close_args *ap)
557 {
558 	struct unionfs_node *unp;
559 	struct unionfs_node_status *unsp;
560 	struct ucred   *cred;
561 	struct thread  *td;
562 	struct vnode   *vp;
563 	struct vnode   *ovp;
564 	int		error;
565 	int		locked;
566 
567 	UNIONFS_INTERNAL_DEBUG("unionfs_close: enter\n");
568 
569 	KASSERT_UNIONFS_VNODE(ap->a_vp);
570 
571 	locked = 0;
572 	vp = ap->a_vp;
573 	unp = VTOUNIONFS(vp);
574 	cred = ap->a_cred;
575 	td = ap->a_td;
576 
577 	if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
578 		if (vn_lock(vp, LK_UPGRADE) != 0)
579 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
580 		locked = 1;
581 	}
582 	unionfs_get_node_status(unp, td, &unsp);
583 
584 	if (unsp->uns_lower_opencnt <= 0 && unsp->uns_upper_opencnt <= 0) {
585 #ifdef DIAGNOSTIC
586 		printf("unionfs_close: warning: open count is 0\n");
587 #endif
588 		if (unp->un_uppervp != NULLVP)
589 			ovp = unp->un_uppervp;
590 		else
591 			ovp = unp->un_lowervp;
592 	} else if (unsp->uns_upper_opencnt > 0)
593 		ovp = unp->un_uppervp;
594 	else
595 		ovp = unp->un_lowervp;
596 
597 	error = VOP_CLOSE(ovp, ap->a_fflag, cred, td);
598 
599 	if (error != 0)
600 		goto unionfs_close_abort;
601 
602 	vp->v_object = ovp->v_object;
603 
604 	if (ovp == unp->un_uppervp) {
605 		unsp->uns_upper_opencnt--;
606 		if (unsp->uns_upper_opencnt == 0) {
607 			if (unsp->uns_node_flag & UNS_OPENL_4_READDIR) {
608 				VOP_CLOSE(unp->un_lowervp, FREAD, cred, td);
609 				unsp->uns_node_flag &= ~UNS_OPENL_4_READDIR;
610 				unsp->uns_lower_opencnt--;
611 			}
612 			if (unsp->uns_lower_opencnt > 0)
613 				vp->v_object = unp->un_lowervp->v_object;
614 		}
615 	} else
616 		unsp->uns_lower_opencnt--;
617 
618 unionfs_close_abort:
619 	unionfs_tryrem_node_status(unp, unsp);
620 
621 	if (locked != 0)
622 		vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
623 
624 	UNIONFS_INTERNAL_DEBUG("unionfs_close: leave (%d)\n", error);
625 
626 	return (error);
627 }
628 
629 /*
630  * Check the access mode toward shadow file/dir.
631  */
632 static int
633 unionfs_check_corrected_access(accmode_t accmode, struct vattr *va,
634     struct ucred *cred)
635 {
636 	uid_t		uid;	/* upper side vnode's uid */
637 	gid_t		gid;	/* upper side vnode's gid */
638 	u_short		vmode;	/* upper side vnode's mode */
639 	u_short		mask;
640 
641 	mask = 0;
642 	uid = va->va_uid;
643 	gid = va->va_gid;
644 	vmode = va->va_mode;
645 
646 	/* check owner */
647 	if (cred->cr_uid == uid) {
648 		if (accmode & VEXEC)
649 			mask |= S_IXUSR;
650 		if (accmode & VREAD)
651 			mask |= S_IRUSR;
652 		if (accmode & VWRITE)
653 			mask |= S_IWUSR;
654 		return ((vmode & mask) == mask ? 0 : EACCES);
655 	}
656 
657 	/* check group */
658 	if (groupmember(gid, cred)) {
659 		if (accmode & VEXEC)
660 			mask |= S_IXGRP;
661 		if (accmode & VREAD)
662 			mask |= S_IRGRP;
663 		if (accmode & VWRITE)
664 			mask |= S_IWGRP;
665 		return ((vmode & mask) == mask ? 0 : EACCES);
666 	}
667 
668 	/* check other */
669 	if (accmode & VEXEC)
670 		mask |= S_IXOTH;
671 	if (accmode & VREAD)
672 		mask |= S_IROTH;
673 	if (accmode & VWRITE)
674 		mask |= S_IWOTH;
675 
676 	return ((vmode & mask) == mask ? 0 : EACCES);
677 }
678 
679 static int
680 unionfs_access(struct vop_access_args *ap)
681 {
682 	struct unionfs_mount *ump;
683 	struct unionfs_node *unp;
684 	struct vnode   *uvp;
685 	struct vnode   *lvp;
686 	struct thread  *td;
687 	struct vattr	va;
688 	accmode_t	accmode;
689 	int		error;
690 
691 	UNIONFS_INTERNAL_DEBUG("unionfs_access: enter\n");
692 
693 	KASSERT_UNIONFS_VNODE(ap->a_vp);
694 
695 	ump = MOUNTTOUNIONFSMOUNT(ap->a_vp->v_mount);
696 	unp = VTOUNIONFS(ap->a_vp);
697 	uvp = unp->un_uppervp;
698 	lvp = unp->un_lowervp;
699 	td = ap->a_td;
700 	accmode = ap->a_accmode;
701 	error = EACCES;
702 
703 	if ((accmode & VWRITE) &&
704 	    (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)) {
705 		switch (ap->a_vp->v_type) {
706 		case VREG:
707 		case VDIR:
708 		case VLNK:
709 			return (EROFS);
710 		default:
711 			break;
712 		}
713 	}
714 
715 	if (uvp != NULLVP) {
716 		error = VOP_ACCESS(uvp, accmode, ap->a_cred, td);
717 
718 		UNIONFS_INTERNAL_DEBUG("unionfs_access: leave (%d)\n", error);
719 
720 		return (error);
721 	}
722 
723 	if (lvp != NULLVP) {
724 		if (accmode & VWRITE) {
725 			if (ump->um_uppervp->v_mount->mnt_flag & MNT_RDONLY) {
726 				switch (ap->a_vp->v_type) {
727 				case VREG:
728 				case VDIR:
729 				case VLNK:
730 					return (EROFS);
731 				default:
732 					break;
733 				}
734 			} else if (ap->a_vp->v_type == VREG ||
735 			    ap->a_vp->v_type == VDIR) {
736 				/* check shadow file/dir */
737 				if (ump->um_copymode != UNIONFS_TRANSPARENT) {
738 					error = unionfs_create_uppervattr(ump,
739 					    lvp, &va, ap->a_cred, td);
740 					if (error != 0)
741 						return (error);
742 
743 					error = unionfs_check_corrected_access(
744 					    accmode, &va, ap->a_cred);
745 					if (error != 0)
746 						return (error);
747 				}
748 			}
749 			accmode &= ~(VWRITE | VAPPEND);
750 			accmode |= VREAD; /* will copy to upper */
751 		}
752 		error = VOP_ACCESS(lvp, accmode, ap->a_cred, td);
753 	}
754 
755 	UNIONFS_INTERNAL_DEBUG("unionfs_access: leave (%d)\n", error);
756 
757 	return (error);
758 }
759 
760 static int
761 unionfs_getattr(struct vop_getattr_args *ap)
762 {
763 	struct unionfs_node *unp;
764 	struct unionfs_mount *ump;
765 	struct vnode   *uvp;
766 	struct vnode   *lvp;
767 	struct thread  *td;
768 	struct vattr	va;
769 	int		error;
770 
771 	UNIONFS_INTERNAL_DEBUG("unionfs_getattr: enter\n");
772 
773 	KASSERT_UNIONFS_VNODE(ap->a_vp);
774 
775 	unp = VTOUNIONFS(ap->a_vp);
776 	ump = MOUNTTOUNIONFSMOUNT(ap->a_vp->v_mount);
777 	uvp = unp->un_uppervp;
778 	lvp = unp->un_lowervp;
779 	td = curthread;
780 
781 	if (uvp != NULLVP) {
782 		if ((error = VOP_GETATTR(uvp, ap->a_vap, ap->a_cred)) == 0)
783 			ap->a_vap->va_fsid =
784 			    ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
785 
786 		UNIONFS_INTERNAL_DEBUG(
787 		    "unionfs_getattr: leave mode=%o, uid=%d, gid=%d (%d)\n",
788 		    ap->a_vap->va_mode, ap->a_vap->va_uid,
789 		    ap->a_vap->va_gid, error);
790 
791 		return (error);
792 	}
793 
794 	error = VOP_GETATTR(lvp, ap->a_vap, ap->a_cred);
795 
796 	if (error == 0 && !(ump->um_uppervp->v_mount->mnt_flag & MNT_RDONLY)) {
797 		/* correct the attr toward shadow file/dir. */
798 		if (ap->a_vp->v_type == VREG || ap->a_vp->v_type == VDIR) {
799 			unionfs_create_uppervattr_core(ump, ap->a_vap, &va, td);
800 			ap->a_vap->va_mode = va.va_mode;
801 			ap->a_vap->va_uid = va.va_uid;
802 			ap->a_vap->va_gid = va.va_gid;
803 		}
804 	}
805 
806 	if (error == 0)
807 		ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
808 
809 	UNIONFS_INTERNAL_DEBUG(
810 	    "unionfs_getattr: leave mode=%o, uid=%d, gid=%d (%d)\n",
811 	    ap->a_vap->va_mode, ap->a_vap->va_uid, ap->a_vap->va_gid, error);
812 
813 	return (error);
814 }
815 
816 static int
817 unionfs_setattr(struct vop_setattr_args *ap)
818 {
819 	struct unionfs_node *unp;
820 	struct vnode   *uvp;
821 	struct vnode   *lvp;
822 	struct thread  *td;
823 	struct vattr   *vap;
824 	int		error;
825 
826 	UNIONFS_INTERNAL_DEBUG("unionfs_setattr: enter\n");
827 
828 	KASSERT_UNIONFS_VNODE(ap->a_vp);
829 
830 	error = EROFS;
831 	unp = VTOUNIONFS(ap->a_vp);
832 	uvp = unp->un_uppervp;
833 	lvp = unp->un_lowervp;
834 	td = curthread;
835 	vap = ap->a_vap;
836 
837 	if ((ap->a_vp->v_mount->mnt_flag & MNT_RDONLY) &&
838 	    (vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
839 	     vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
840 	     vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL))
841 		return (EROFS);
842 
843 	if (uvp == NULLVP && lvp->v_type == VREG) {
844 		error = unionfs_copyfile(unp, (vap->va_size != 0),
845 		    ap->a_cred, td);
846 		if (error != 0)
847 			return (error);
848 		uvp = unp->un_uppervp;
849 	}
850 
851 	if (uvp != NULLVP)
852 		error = VOP_SETATTR(uvp, vap, ap->a_cred);
853 
854 	UNIONFS_INTERNAL_DEBUG("unionfs_setattr: leave (%d)\n", error);
855 
856 	return (error);
857 }
858 
859 static int
860 unionfs_read(struct vop_read_args *ap)
861 {
862 	struct unionfs_node *unp;
863 	struct vnode   *tvp;
864 	int		error;
865 
866 	/* UNIONFS_INTERNAL_DEBUG("unionfs_read: enter\n"); */
867 
868 	KASSERT_UNIONFS_VNODE(ap->a_vp);
869 
870 	unp = VTOUNIONFS(ap->a_vp);
871 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
872 
873 	error = VOP_READ(tvp, ap->a_uio, ap->a_ioflag, ap->a_cred);
874 
875 	/* UNIONFS_INTERNAL_DEBUG("unionfs_read: leave (%d)\n", error); */
876 
877 	return (error);
878 }
879 
880 static int
881 unionfs_write(struct vop_write_args *ap)
882 {
883 	struct unionfs_node *unp;
884 	struct vnode   *tvp;
885 	int		error;
886 
887 	/* UNIONFS_INTERNAL_DEBUG("unionfs_write: enter\n"); */
888 
889 	KASSERT_UNIONFS_VNODE(ap->a_vp);
890 
891 	unp = VTOUNIONFS(ap->a_vp);
892 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
893 
894 	error = VOP_WRITE(tvp, ap->a_uio, ap->a_ioflag, ap->a_cred);
895 
896 	/* UNIONFS_INTERNAL_DEBUG("unionfs_write: leave (%d)\n", error); */
897 
898 	return (error);
899 }
900 
901 static int
902 unionfs_ioctl(struct vop_ioctl_args *ap)
903 {
904 	struct unionfs_node *unp;
905 	struct unionfs_node_status *unsp;
906 	struct vnode   *ovp;
907 	int error;
908 
909 	UNIONFS_INTERNAL_DEBUG("unionfs_ioctl: enter\n");
910 
911 	KASSERT_UNIONFS_VNODE(ap->a_vp);
912 
913  	vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
914 	unp = VTOUNIONFS(ap->a_vp);
915 	unionfs_get_node_status(unp, ap->a_td, &unsp);
916 	ovp = (unsp->uns_upper_opencnt ? unp->un_uppervp : unp->un_lowervp);
917 	unionfs_tryrem_node_status(unp, unsp);
918 	VOP_UNLOCK(ap->a_vp);
919 
920 	if (ovp == NULLVP)
921 		return (EBADF);
922 
923 	error = VOP_IOCTL(ovp, ap->a_command, ap->a_data, ap->a_fflag,
924 	    ap->a_cred, ap->a_td);
925 
926 	UNIONFS_INTERNAL_DEBUG("unionfs_ioctl: leave (%d)\n", error);
927 
928 	return (error);
929 }
930 
931 static int
932 unionfs_poll(struct vop_poll_args *ap)
933 {
934 	struct unionfs_node *unp;
935 	struct unionfs_node_status *unsp;
936 	struct vnode *ovp;
937 
938 	KASSERT_UNIONFS_VNODE(ap->a_vp);
939 
940  	vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
941 	unp = VTOUNIONFS(ap->a_vp);
942 	unionfs_get_node_status(unp, ap->a_td, &unsp);
943 	ovp = (unsp->uns_upper_opencnt ? unp->un_uppervp : unp->un_lowervp);
944 	unionfs_tryrem_node_status(unp, unsp);
945 	VOP_UNLOCK(ap->a_vp);
946 
947 	if (ovp == NULLVP)
948 		return (EBADF);
949 
950 	return (VOP_POLL(ovp, ap->a_events, ap->a_cred, ap->a_td));
951 }
952 
953 static int
954 unionfs_fsync(struct vop_fsync_args *ap)
955 {
956 	struct unionfs_node *unp;
957 	struct unionfs_node_status *unsp;
958 	struct vnode *ovp;
959 
960 	KASSERT_UNIONFS_VNODE(ap->a_vp);
961 
962 	unp = VTOUNIONFS(ap->a_vp);
963 	unionfs_get_node_status(unp, ap->a_td, &unsp);
964 	ovp = (unsp->uns_upper_opencnt ? unp->un_uppervp : unp->un_lowervp);
965 	unionfs_tryrem_node_status(unp, unsp);
966 
967 	if (ovp == NULLVP)
968 		return (EBADF);
969 
970 	return (VOP_FSYNC(ovp, ap->a_waitfor, ap->a_td));
971 }
972 
973 static int
974 unionfs_remove(struct vop_remove_args *ap)
975 {
976 	char	       *path;
977 	struct unionfs_node *dunp;
978 	struct unionfs_node *unp;
979 	struct unionfs_mount *ump;
980 	struct vnode   *udvp;
981 	struct vnode   *uvp;
982 	struct vnode   *lvp;
983 	struct vnode   *vp;
984 	struct componentname *cnp;
985 	struct componentname cn;
986 	struct thread  *td;
987 	int		error;
988 	int		pathlen;
989 
990 	UNIONFS_INTERNAL_DEBUG("unionfs_remove: enter\n");
991 
992 	KASSERT_UNIONFS_VNODE(ap->a_dvp);
993 
994 	error = 0;
995 	dunp = VTOUNIONFS(ap->a_dvp);
996 	udvp = dunp->un_uppervp;
997 	cnp = ap->a_cnp;
998 	td = curthread;
999 
1000 	if (ap->a_vp->v_op != &unionfs_vnodeops) {
1001 		if (ap->a_vp->v_type != VSOCK)
1002 			return (EINVAL);
1003 		ump = NULL;
1004 		vp = uvp = lvp = NULLVP;
1005 		/* search vnode */
1006 		VOP_UNLOCK(ap->a_vp);
1007 		error = unionfs_relookup(udvp, &vp, cnp, &cn, td,
1008 		    cnp->cn_nameptr, cnp->cn_namelen, DELETE);
1009 		if (error != 0 && error != ENOENT) {
1010 			vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
1011 			return (error);
1012 		}
1013 
1014 		if (error == 0 && vp == ap->a_vp) {
1015 			/* target vnode in upper */
1016 			uvp = vp;
1017 			vrele(vp);
1018 		} else {
1019 			/* target vnode in lower */
1020 			if (vp != NULLVP) {
1021 				if (udvp == vp)
1022 					vrele(vp);
1023 				else
1024 					vput(vp);
1025 			}
1026 			vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
1027 			lvp = ap->a_vp;
1028 		}
1029 		path = cnp->cn_nameptr;
1030 		pathlen = cnp->cn_namelen;
1031 	} else {
1032 		ump = MOUNTTOUNIONFSMOUNT(ap->a_vp->v_mount);
1033 		unp = VTOUNIONFS(ap->a_vp);
1034 		uvp = unp->un_uppervp;
1035 		lvp = unp->un_lowervp;
1036 		path = unp->un_path;
1037 		pathlen = unp->un_pathlen;
1038 	}
1039 
1040 	if (udvp == NULLVP)
1041 		return (EROFS);
1042 
1043 	if (uvp != NULLVP) {
1044 		/*
1045 		 * XXX: if the vnode type is VSOCK, it will create whiteout
1046 		 *      after remove.
1047 		 */
1048 		if (ump == NULL || ump->um_whitemode == UNIONFS_WHITE_ALWAYS ||
1049 		    lvp != NULLVP)
1050 			cnp->cn_flags |= DOWHITEOUT;
1051 		error = VOP_REMOVE(udvp, uvp, cnp);
1052 	} else if (lvp != NULLVP)
1053 		error = unionfs_mkwhiteout(udvp, cnp, td, path, pathlen);
1054 
1055 	UNIONFS_INTERNAL_DEBUG("unionfs_remove: leave (%d)\n", error);
1056 
1057 	return (error);
1058 }
1059 
1060 static int
1061 unionfs_link(struct vop_link_args *ap)
1062 {
1063 	struct unionfs_node *dunp;
1064 	struct unionfs_node *unp;
1065 	struct vnode   *udvp;
1066 	struct vnode   *uvp;
1067 	struct componentname *cnp;
1068 	struct thread  *td;
1069 	int		error;
1070 	int		needrelookup;
1071 
1072 	UNIONFS_INTERNAL_DEBUG("unionfs_link: enter\n");
1073 
1074 	KASSERT_UNIONFS_VNODE(ap->a_tdvp);
1075 	KASSERT_UNIONFS_VNODE(ap->a_vp);
1076 
1077 	error = 0;
1078 	needrelookup = 0;
1079 	dunp = VTOUNIONFS(ap->a_tdvp);
1080 	unp = NULL;
1081 	udvp = dunp->un_uppervp;
1082 	uvp = NULLVP;
1083 	cnp = ap->a_cnp;
1084 	td = curthread;
1085 
1086 	if (udvp == NULLVP)
1087 		return (EROFS);
1088 
1089 	if (ap->a_vp->v_op != &unionfs_vnodeops)
1090 		uvp = ap->a_vp;
1091 	else {
1092 		unp = VTOUNIONFS(ap->a_vp);
1093 
1094 		if (unp->un_uppervp == NULLVP) {
1095 			if (ap->a_vp->v_type != VREG)
1096 				return (EOPNOTSUPP);
1097 
1098 			error = unionfs_copyfile(unp, 1, cnp->cn_cred, td);
1099 			if (error != 0)
1100 				return (error);
1101 			needrelookup = 1;
1102 		}
1103 		uvp = unp->un_uppervp;
1104 	}
1105 
1106 	if (needrelookup != 0)
1107 		error = unionfs_relookup_for_create(ap->a_tdvp, cnp, td);
1108 
1109 	if (error == 0)
1110 		error = VOP_LINK(udvp, uvp, cnp);
1111 
1112 	UNIONFS_INTERNAL_DEBUG("unionfs_link: leave (%d)\n", error);
1113 
1114 	return (error);
1115 }
1116 
1117 static int
1118 unionfs_rename(struct vop_rename_args *ap)
1119 {
1120 	struct vnode   *fdvp;
1121 	struct vnode   *fvp;
1122 	struct componentname *fcnp;
1123 	struct vnode   *tdvp;
1124 	struct vnode   *tvp;
1125 	struct componentname *tcnp;
1126 	struct vnode   *ltdvp;
1127 	struct vnode   *ltvp;
1128 	struct thread  *td;
1129 
1130 	/* rename target vnodes */
1131 	struct vnode   *rfdvp;
1132 	struct vnode   *rfvp;
1133 	struct vnode   *rtdvp;
1134 	struct vnode   *rtvp;
1135 
1136 	struct unionfs_mount *ump;
1137 	struct unionfs_node *unp;
1138 	int		error;
1139 	int		needrelookup;
1140 
1141 	UNIONFS_INTERNAL_DEBUG("unionfs_rename: enter\n");
1142 
1143 	error = 0;
1144 	fdvp = ap->a_fdvp;
1145 	fvp = ap->a_fvp;
1146 	fcnp = ap->a_fcnp;
1147 	tdvp = ap->a_tdvp;
1148 	tvp = ap->a_tvp;
1149 	tcnp = ap->a_tcnp;
1150 	ltdvp = NULLVP;
1151 	ltvp = NULLVP;
1152 	td = curthread;
1153 	rfdvp = fdvp;
1154 	rfvp = fvp;
1155 	rtdvp = tdvp;
1156 	rtvp = tvp;
1157 	needrelookup = 0;
1158 
1159 #ifdef DIAGNOSTIC
1160 	if (!(fcnp->cn_flags & HASBUF) || !(tcnp->cn_flags & HASBUF))
1161 		panic("unionfs_rename: no name");
1162 #endif
1163 
1164 	/* check for cross device rename */
1165 	if (fvp->v_mount != tdvp->v_mount ||
1166 	    (tvp != NULLVP && fvp->v_mount != tvp->v_mount)) {
1167 		if (fvp->v_op != &unionfs_vnodeops)
1168 			error = ENODEV;
1169 		else
1170 			error = EXDEV;
1171 		goto unionfs_rename_abort;
1172 	}
1173 
1174 	/* Renaming a file to itself has no effect. */
1175 	if (fvp == tvp)
1176 		goto unionfs_rename_abort;
1177 
1178 	/*
1179 	 * from/to vnode is unionfs node.
1180 	 */
1181 
1182 	KASSERT_UNIONFS_VNODE(fdvp);
1183 	KASSERT_UNIONFS_VNODE(fvp);
1184 	KASSERT_UNIONFS_VNODE(tdvp);
1185 	if (tvp != NULLVP)
1186 		KASSERT_UNIONFS_VNODE(tvp);
1187 
1188 	unp = VTOUNIONFS(fdvp);
1189 #ifdef UNIONFS_IDBG_RENAME
1190 	UNIONFS_INTERNAL_DEBUG("fdvp=%p, ufdvp=%p, lfdvp=%p\n",
1191 	    fdvp, unp->un_uppervp, unp->un_lowervp);
1192 #endif
1193 	if (unp->un_uppervp == NULLVP) {
1194 		error = ENODEV;
1195 		goto unionfs_rename_abort;
1196 	}
1197 	rfdvp = unp->un_uppervp;
1198 	vref(rfdvp);
1199 
1200 	unp = VTOUNIONFS(fvp);
1201 #ifdef UNIONFS_IDBG_RENAME
1202 	UNIONFS_INTERNAL_DEBUG("fvp=%p, ufvp=%p, lfvp=%p\n",
1203 	    fvp, unp->un_uppervp, unp->un_lowervp);
1204 #endif
1205 	ump = MOUNTTOUNIONFSMOUNT(fvp->v_mount);
1206 	if (unp->un_uppervp == NULLVP) {
1207 		switch (fvp->v_type) {
1208 		case VREG:
1209 			if ((error = vn_lock(fvp, LK_EXCLUSIVE)) != 0)
1210 				goto unionfs_rename_abort;
1211 			error = unionfs_copyfile(unp, 1, fcnp->cn_cred, td);
1212 			VOP_UNLOCK(fvp);
1213 			if (error != 0)
1214 				goto unionfs_rename_abort;
1215 			break;
1216 		case VDIR:
1217 			if ((error = vn_lock(fvp, LK_EXCLUSIVE)) != 0)
1218 				goto unionfs_rename_abort;
1219 			error = unionfs_mkshadowdir(ump, rfdvp, unp, fcnp, td);
1220 			VOP_UNLOCK(fvp);
1221 			if (error != 0)
1222 				goto unionfs_rename_abort;
1223 			break;
1224 		default:
1225 			error = ENODEV;
1226 			goto unionfs_rename_abort;
1227 		}
1228 
1229 		needrelookup = 1;
1230 	}
1231 
1232 	if (unp->un_lowervp != NULLVP)
1233 		fcnp->cn_flags |= DOWHITEOUT;
1234 	rfvp = unp->un_uppervp;
1235 	vref(rfvp);
1236 
1237 	unp = VTOUNIONFS(tdvp);
1238 #ifdef UNIONFS_IDBG_RENAME
1239 	UNIONFS_INTERNAL_DEBUG("tdvp=%p, utdvp=%p, ltdvp=%p\n",
1240 	    tdvp, unp->un_uppervp, unp->un_lowervp);
1241 #endif
1242 	if (unp->un_uppervp == NULLVP) {
1243 		error = ENODEV;
1244 		goto unionfs_rename_abort;
1245 	}
1246 	rtdvp = unp->un_uppervp;
1247 	ltdvp = unp->un_lowervp;
1248 	vref(rtdvp);
1249 
1250 	if (tdvp == tvp) {
1251 		rtvp = rtdvp;
1252 		vref(rtvp);
1253 	} else if (tvp != NULLVP) {
1254 		unp = VTOUNIONFS(tvp);
1255 #ifdef UNIONFS_IDBG_RENAME
1256 		UNIONFS_INTERNAL_DEBUG("tvp=%p, utvp=%p, ltvp=%p\n",
1257 		    tvp, unp->un_uppervp, unp->un_lowervp);
1258 #endif
1259 		if (unp->un_uppervp == NULLVP)
1260 			rtvp = NULLVP;
1261 		else {
1262 			if (tvp->v_type == VDIR) {
1263 				error = EINVAL;
1264 				goto unionfs_rename_abort;
1265 			}
1266 			rtvp = unp->un_uppervp;
1267 			ltvp = unp->un_lowervp;
1268 			vref(rtvp);
1269 		}
1270 	}
1271 
1272 	if (rfvp == rtvp)
1273 		goto unionfs_rename_abort;
1274 
1275 	if (needrelookup != 0) {
1276 		if ((error = vn_lock(fdvp, LK_EXCLUSIVE)) != 0)
1277 			goto unionfs_rename_abort;
1278 		error = unionfs_relookup_for_delete(fdvp, fcnp, td);
1279 		VOP_UNLOCK(fdvp);
1280 		if (error != 0)
1281 			goto unionfs_rename_abort;
1282 
1283 		/* Lock of tvp is canceled in order to avoid recursive lock. */
1284 		if (tvp != NULLVP && tvp != tdvp)
1285 			VOP_UNLOCK(tvp);
1286 		error = unionfs_relookup_for_rename(tdvp, tcnp, td);
1287 		if (tvp != NULLVP && tvp != tdvp)
1288 			vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY);
1289 		if (error != 0)
1290 			goto unionfs_rename_abort;
1291 	}
1292 
1293 	error = VOP_RENAME(rfdvp, rfvp, fcnp, rtdvp, rtvp, tcnp);
1294 
1295 	if (error == 0) {
1296 		if (rtvp != NULLVP && rtvp->v_type == VDIR)
1297 			cache_purge(tdvp);
1298 		if (fvp->v_type == VDIR && fdvp != tdvp)
1299 			cache_purge(fdvp);
1300 	}
1301 
1302 	if (ltdvp != NULLVP)
1303 		VOP_UNLOCK(ltdvp);
1304 	if (tdvp != rtdvp)
1305 		vrele(tdvp);
1306 	if (ltvp != NULLVP)
1307 		VOP_UNLOCK(ltvp);
1308 	if (tvp != rtvp && tvp != NULLVP) {
1309 		if (rtvp == NULLVP)
1310 			vput(tvp);
1311 		else
1312 			vrele(tvp);
1313 	}
1314 	if (fdvp != rfdvp)
1315 		vrele(fdvp);
1316 	if (fvp != rfvp)
1317 		vrele(fvp);
1318 
1319 	UNIONFS_INTERNAL_DEBUG("unionfs_rename: leave (%d)\n", error);
1320 
1321 	return (error);
1322 
1323 unionfs_rename_abort:
1324 	vput(tdvp);
1325 	if (tdvp != rtdvp)
1326 		vrele(rtdvp);
1327 	if (tvp != NULLVP) {
1328 		if (tdvp != tvp)
1329 			vput(tvp);
1330 		else
1331 			vrele(tvp);
1332 	}
1333 	if (tvp != rtvp && rtvp != NULLVP)
1334 		vrele(rtvp);
1335 	if (fdvp != rfdvp)
1336 		vrele(rfdvp);
1337 	if (fvp != rfvp)
1338 		vrele(rfvp);
1339 	vrele(fdvp);
1340 	vrele(fvp);
1341 
1342 	UNIONFS_INTERNAL_DEBUG("unionfs_rename: leave (%d)\n", error);
1343 
1344 	return (error);
1345 }
1346 
1347 static int
1348 unionfs_mkdir(struct vop_mkdir_args *ap)
1349 {
1350 	struct unionfs_node *dunp;
1351 	struct componentname *cnp;
1352 	struct vnode   *udvp;
1353 	struct vnode   *uvp;
1354 	struct vattr	va;
1355 	int		error;
1356 	int		lkflags;
1357 
1358 	UNIONFS_INTERNAL_DEBUG("unionfs_mkdir: enter\n");
1359 
1360 	KASSERT_UNIONFS_VNODE(ap->a_dvp);
1361 
1362 	error = EROFS;
1363 	dunp = VTOUNIONFS(ap->a_dvp);
1364 	cnp = ap->a_cnp;
1365 	lkflags = cnp->cn_lkflags;
1366 	udvp = dunp->un_uppervp;
1367 
1368 	if (udvp != NULLVP) {
1369 		/* check opaque */
1370 		if (!(cnp->cn_flags & ISWHITEOUT)) {
1371 			error = VOP_GETATTR(udvp, &va, cnp->cn_cred);
1372 			if (error != 0)
1373 				return (error);
1374 			if ((va.va_flags & OPAQUE) != 0)
1375 				cnp->cn_flags |= ISWHITEOUT;
1376 		}
1377 
1378 		if ((error = VOP_MKDIR(udvp, &uvp, cnp, ap->a_vap)) == 0) {
1379 			VOP_UNLOCK(uvp);
1380 			cnp->cn_lkflags = LK_EXCLUSIVE;
1381 			error = unionfs_nodeget(ap->a_dvp->v_mount, uvp, NULLVP,
1382 			    ap->a_dvp, ap->a_vpp, cnp);
1383 			cnp->cn_lkflags = lkflags;
1384 			vrele(uvp);
1385 		}
1386 	}
1387 
1388 	UNIONFS_INTERNAL_DEBUG("unionfs_mkdir: leave (%d)\n", error);
1389 
1390 	return (error);
1391 }
1392 
1393 static int
1394 unionfs_rmdir(struct vop_rmdir_args *ap)
1395 {
1396 	struct unionfs_node *dunp;
1397 	struct unionfs_node *unp;
1398 	struct unionfs_mount *ump;
1399 	struct componentname *cnp;
1400 	struct thread  *td;
1401 	struct vnode   *udvp;
1402 	struct vnode   *uvp;
1403 	struct vnode   *lvp;
1404 	int		error;
1405 
1406 	UNIONFS_INTERNAL_DEBUG("unionfs_rmdir: enter\n");
1407 
1408 	KASSERT_UNIONFS_VNODE(ap->a_dvp);
1409 	KASSERT_UNIONFS_VNODE(ap->a_vp);
1410 
1411 	error = 0;
1412 	dunp = VTOUNIONFS(ap->a_dvp);
1413 	unp = VTOUNIONFS(ap->a_vp);
1414 	cnp = ap->a_cnp;
1415 	td = curthread;
1416 	udvp = dunp->un_uppervp;
1417 	uvp = unp->un_uppervp;
1418 	lvp = unp->un_lowervp;
1419 
1420 	if (udvp == NULLVP)
1421 		return (EROFS);
1422 
1423 	if (udvp == uvp)
1424 		return (EOPNOTSUPP);
1425 
1426 	if (uvp != NULLVP) {
1427 		if (lvp != NULLVP) {
1428 			error = unionfs_check_rmdir(ap->a_vp, cnp->cn_cred, td);
1429 			if (error != 0)
1430 				return (error);
1431 		}
1432 		ump = MOUNTTOUNIONFSMOUNT(ap->a_vp->v_mount);
1433 		if (ump->um_whitemode == UNIONFS_WHITE_ALWAYS || lvp != NULLVP)
1434 			cnp->cn_flags |= DOWHITEOUT;
1435 		/*
1436 		 * The relookup path will need to relock the parent dvp and
1437 		 * possibly the vp as well.  Locking is expected to be done
1438 		 * in parent->child order; drop the lock on vp to avoid LOR
1439 		 * and potential recursion on vp's lock.
1440 		 * vp is expected to remain referenced during VOP_RMDIR(),
1441 		 * so vref/vrele should not be necessary here.
1442 		 */
1443 		VOP_UNLOCK(ap->a_vp);
1444 		VNPASS(vrefcnt(ap->a_vp) > 0, ap->a_vp);
1445 		error = unionfs_relookup_for_delete(ap->a_dvp, cnp, td);
1446 		vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
1447 		if (error == 0 && VN_IS_DOOMED(uvp))
1448 			error = ENOENT;
1449 		if (error == 0)
1450 			error = VOP_RMDIR(udvp, uvp, cnp);
1451 	} else if (lvp != NULLVP)
1452 		error = unionfs_mkwhiteout(udvp, cnp, td,
1453 		    unp->un_path, unp->un_pathlen);
1454 
1455 	if (error == 0) {
1456 		cache_purge(ap->a_dvp);
1457 		cache_purge(ap->a_vp);
1458 	}
1459 
1460 	UNIONFS_INTERNAL_DEBUG("unionfs_rmdir: leave (%d)\n", error);
1461 
1462 	return (error);
1463 }
1464 
1465 static int
1466 unionfs_symlink(struct vop_symlink_args *ap)
1467 {
1468 	struct unionfs_node *dunp;
1469 	struct componentname *cnp;
1470 	struct vnode   *udvp;
1471 	struct vnode   *uvp;
1472 	int		error;
1473 	int		lkflags;
1474 
1475 	UNIONFS_INTERNAL_DEBUG("unionfs_symlink: enter\n");
1476 
1477 	KASSERT_UNIONFS_VNODE(ap->a_dvp);
1478 
1479 	error = EROFS;
1480 	dunp = VTOUNIONFS(ap->a_dvp);
1481 	cnp = ap->a_cnp;
1482 	lkflags = cnp->cn_lkflags;
1483 	udvp = dunp->un_uppervp;
1484 
1485 	if (udvp != NULLVP) {
1486 		error = VOP_SYMLINK(udvp, &uvp, cnp, ap->a_vap, ap->a_target);
1487 		if (error == 0) {
1488 			VOP_UNLOCK(uvp);
1489 			cnp->cn_lkflags = LK_EXCLUSIVE;
1490 			error = unionfs_nodeget(ap->a_dvp->v_mount, uvp, NULLVP,
1491 			    ap->a_dvp, ap->a_vpp, cnp);
1492 			cnp->cn_lkflags = lkflags;
1493 			vrele(uvp);
1494 		}
1495 	}
1496 
1497 	UNIONFS_INTERNAL_DEBUG("unionfs_symlink: leave (%d)\n", error);
1498 
1499 	return (error);
1500 }
1501 
1502 static int
1503 unionfs_readdir(struct vop_readdir_args *ap)
1504 {
1505 	struct unionfs_node *unp;
1506 	struct unionfs_node_status *unsp;
1507 	struct uio     *uio;
1508 	struct vnode   *vp;
1509 	struct vnode   *uvp;
1510 	struct vnode   *lvp;
1511 	struct thread  *td;
1512 	struct vattr    va;
1513 
1514 	uint64_t	*cookies_bk;
1515 	int		error;
1516 	int		eofflag;
1517 	int		locked;
1518 	int		ncookies_bk;
1519 	int		uio_offset_bk;
1520 
1521 	UNIONFS_INTERNAL_DEBUG("unionfs_readdir: enter\n");
1522 
1523 	KASSERT_UNIONFS_VNODE(ap->a_vp);
1524 
1525 	error = 0;
1526 	eofflag = 0;
1527 	locked = 0;
1528 	uio_offset_bk = 0;
1529 	uio = ap->a_uio;
1530 	uvp = NULLVP;
1531 	lvp = NULLVP;
1532 	td = uio->uio_td;
1533 	ncookies_bk = 0;
1534 	cookies_bk = NULL;
1535 
1536 	vp = ap->a_vp;
1537 	if (vp->v_type != VDIR)
1538 		return (ENOTDIR);
1539 
1540 	/* check the open count. unionfs needs to open before readdir. */
1541 	if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
1542 		if (vn_lock(vp, LK_UPGRADE) != 0)
1543 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1544 		locked = 1;
1545 	}
1546 	unp = VTOUNIONFS(vp);
1547 	if (unp == NULL)
1548 		error = EBADF;
1549 	else {
1550 		uvp = unp->un_uppervp;
1551 		lvp = unp->un_lowervp;
1552 		unionfs_get_node_status(unp, td, &unsp);
1553 		if ((uvp != NULLVP && unsp->uns_upper_opencnt <= 0) ||
1554 			(lvp != NULLVP && unsp->uns_lower_opencnt <= 0)) {
1555 			unionfs_tryrem_node_status(unp, unsp);
1556 			error = EBADF;
1557 		}
1558 	}
1559 	if (locked)
1560 		vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
1561 	if (error != 0)
1562 		goto unionfs_readdir_exit;
1563 
1564 	/* check opaque */
1565 	if (uvp != NULLVP && lvp != NULLVP) {
1566 		if ((error = VOP_GETATTR(uvp, &va, ap->a_cred)) != 0)
1567 			goto unionfs_readdir_exit;
1568 		if (va.va_flags & OPAQUE)
1569 			lvp = NULLVP;
1570 	}
1571 
1572 	/* upper only */
1573 	if (uvp != NULLVP && lvp == NULLVP) {
1574 		error = VOP_READDIR(uvp, uio, ap->a_cred, ap->a_eofflag,
1575 		    ap->a_ncookies, ap->a_cookies);
1576 		unsp->uns_readdir_status = 0;
1577 
1578 		goto unionfs_readdir_exit;
1579 	}
1580 
1581 	/* lower only */
1582 	if (uvp == NULLVP && lvp != NULLVP) {
1583 		error = VOP_READDIR(lvp, uio, ap->a_cred, ap->a_eofflag,
1584 		    ap->a_ncookies, ap->a_cookies);
1585 		unsp->uns_readdir_status = 2;
1586 
1587 		goto unionfs_readdir_exit;
1588 	}
1589 
1590 	/*
1591 	 * readdir upper and lower
1592 	 */
1593 	KASSERT(uvp != NULLVP, ("unionfs_readdir: null upper vp"));
1594 	KASSERT(lvp != NULLVP, ("unionfs_readdir: null lower vp"));
1595 	if (uio->uio_offset == 0)
1596 		unsp->uns_readdir_status = 0;
1597 
1598 	if (unsp->uns_readdir_status == 0) {
1599 		/* read upper */
1600 		error = VOP_READDIR(uvp, uio, ap->a_cred, &eofflag,
1601 				    ap->a_ncookies, ap->a_cookies);
1602 
1603 		if (error != 0 || eofflag == 0)
1604 			goto unionfs_readdir_exit;
1605 		unsp->uns_readdir_status = 1;
1606 
1607 		/*
1608 		 * UFS(and other FS) needs size of uio_resid larger than
1609 		 * DIRBLKSIZ.
1610 		 * size of DIRBLKSIZ equals DEV_BSIZE.
1611 		 * (see: ufs/ufs/ufs_vnops.c ufs_readdir func , ufs/ufs/dir.h)
1612 		 */
1613 		if (uio->uio_resid <= (uio->uio_resid & (DEV_BSIZE -1)))
1614 			goto unionfs_readdir_exit;
1615 
1616 		/*
1617 		 * Backup cookies.
1618 		 * It prepares to readdir in lower.
1619 		 */
1620 		if (ap->a_ncookies != NULL) {
1621 			ncookies_bk = *(ap->a_ncookies);
1622 			*(ap->a_ncookies) = 0;
1623 		}
1624 		if (ap->a_cookies != NULL) {
1625 			cookies_bk = *(ap->a_cookies);
1626 			*(ap->a_cookies) = NULL;
1627 		}
1628 	}
1629 
1630 	/* initialize for readdir in lower */
1631 	if (unsp->uns_readdir_status == 1) {
1632 		unsp->uns_readdir_status = 2;
1633 		/*
1634 		 * Backup uio_offset. See the comment after the
1635 		 * VOP_READDIR call on the lower layer.
1636 		 */
1637 		uio_offset_bk = uio->uio_offset;
1638 		uio->uio_offset = 0;
1639 	}
1640 
1641 	if (lvp == NULLVP) {
1642 		error = EBADF;
1643 		goto unionfs_readdir_exit;
1644 	}
1645 	/* read lower */
1646 	error = VOP_READDIR(lvp, uio, ap->a_cred, ap->a_eofflag,
1647 			    ap->a_ncookies, ap->a_cookies);
1648 
1649 	/*
1650 	 * We can't return an uio_offset of 0: this would trigger an
1651 	 * infinite loop, because the next call to unionfs_readdir would
1652 	 * always restart with the upper layer (uio_offset == 0) and
1653 	 * always return some data.
1654 	 *
1655 	 * This happens when the lower layer root directory is removed.
1656 	 * (A root directory deleting of unionfs should not be permitted.
1657 	 *  But current VFS can not do it.)
1658 	 */
1659 	if (uio->uio_offset == 0)
1660 		uio->uio_offset = uio_offset_bk;
1661 
1662 	if (cookies_bk != NULL) {
1663 		/* merge cookies */
1664 		int		size;
1665 		uint64_t         *newcookies, *pos;
1666 
1667 		size = *(ap->a_ncookies) + ncookies_bk;
1668 		newcookies = (uint64_t *) malloc(size * sizeof(*newcookies),
1669 		    M_TEMP, M_WAITOK);
1670 		pos = newcookies;
1671 
1672 		memcpy(pos, cookies_bk, ncookies_bk * sizeof(*newcookies));
1673 		pos += ncookies_bk;
1674 		memcpy(pos, *(ap->a_cookies),
1675 		    *(ap->a_ncookies) * sizeof(*newcookies));
1676 		free(cookies_bk, M_TEMP);
1677 		free(*(ap->a_cookies), M_TEMP);
1678 		*(ap->a_ncookies) = size;
1679 		*(ap->a_cookies) = newcookies;
1680 	}
1681 
1682 unionfs_readdir_exit:
1683 	if (error != 0 && ap->a_eofflag != NULL)
1684 		*(ap->a_eofflag) = 1;
1685 
1686 	UNIONFS_INTERNAL_DEBUG("unionfs_readdir: leave (%d)\n", error);
1687 
1688 	return (error);
1689 }
1690 
1691 static int
1692 unionfs_readlink(struct vop_readlink_args *ap)
1693 {
1694 	struct unionfs_node *unp;
1695 	struct vnode   *vp;
1696 	int error;
1697 
1698 	UNIONFS_INTERNAL_DEBUG("unionfs_readlink: enter\n");
1699 
1700 	KASSERT_UNIONFS_VNODE(ap->a_vp);
1701 
1702 	unp = VTOUNIONFS(ap->a_vp);
1703 	vp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
1704 
1705 	error = VOP_READLINK(vp, ap->a_uio, ap->a_cred);
1706 
1707 	UNIONFS_INTERNAL_DEBUG("unionfs_readlink: leave (%d)\n", error);
1708 
1709 	return (error);
1710 }
1711 
1712 static int
1713 unionfs_getwritemount(struct vop_getwritemount_args *ap)
1714 {
1715 	struct vnode   *uvp;
1716 	struct vnode   *vp;
1717 	int		error;
1718 
1719 	UNIONFS_INTERNAL_DEBUG("unionfs_getwritemount: enter\n");
1720 
1721 	error = 0;
1722 	vp = ap->a_vp;
1723 
1724 	if (vp == NULLVP || (vp->v_mount->mnt_flag & MNT_RDONLY))
1725 		return (EACCES);
1726 
1727 	KASSERT_UNIONFS_VNODE(vp);
1728 
1729 	uvp = UNIONFSVPTOUPPERVP(vp);
1730 	if (uvp == NULLVP && VREG == vp->v_type)
1731 		uvp = UNIONFSVPTOUPPERVP(VTOUNIONFS(vp)->un_dvp);
1732 
1733 	if (uvp != NULLVP)
1734 		error = VOP_GETWRITEMOUNT(uvp, ap->a_mpp);
1735 	else {
1736 		VI_LOCK(vp);
1737 		if (vp->v_holdcnt == 0)
1738 			error = EOPNOTSUPP;
1739 		else
1740 			error = EACCES;
1741 		VI_UNLOCK(vp);
1742 	}
1743 
1744 	UNIONFS_INTERNAL_DEBUG("unionfs_getwritemount: leave (%d)\n", error);
1745 
1746 	return (error);
1747 }
1748 
1749 static int
1750 unionfs_inactive(struct vop_inactive_args *ap)
1751 {
1752 	ap->a_vp->v_object = NULL;
1753 	vrecycle(ap->a_vp);
1754 	return (0);
1755 }
1756 
1757 static int
1758 unionfs_reclaim(struct vop_reclaim_args *ap)
1759 {
1760 	/* UNIONFS_INTERNAL_DEBUG("unionfs_reclaim: enter\n"); */
1761 
1762 	unionfs_noderem(ap->a_vp);
1763 
1764 	/* UNIONFS_INTERNAL_DEBUG("unionfs_reclaim: leave\n"); */
1765 
1766 	return (0);
1767 }
1768 
1769 static int
1770 unionfs_print(struct vop_print_args *ap)
1771 {
1772 	struct unionfs_node *unp;
1773 	/* struct unionfs_node_status *unsp; */
1774 
1775 	unp = VTOUNIONFS(ap->a_vp);
1776 	/* unionfs_get_node_status(unp, curthread, &unsp); */
1777 
1778 	printf("unionfs_vp=%p, uppervp=%p, lowervp=%p\n",
1779 	    ap->a_vp, unp->un_uppervp, unp->un_lowervp);
1780 	/*
1781 	printf("unionfs opencnt: uppervp=%d, lowervp=%d\n",
1782 	    unsp->uns_upper_opencnt, unsp->uns_lower_opencnt);
1783 	*/
1784 
1785 	if (unp->un_uppervp != NULLVP)
1786 		vn_printf(unp->un_uppervp, "unionfs: upper ");
1787 	if (unp->un_lowervp != NULLVP)
1788 		vn_printf(unp->un_lowervp, "unionfs: lower ");
1789 
1790 	return (0);
1791 }
1792 
1793 static int
1794 unionfs_islocked(struct vop_islocked_args *ap)
1795 {
1796 	struct unionfs_node *unp;
1797 
1798 	KASSERT_UNIONFS_VNODE(ap->a_vp);
1799 
1800 	unp = VTOUNIONFS(ap->a_vp);
1801 	if (unp == NULL)
1802 		return (vop_stdislocked(ap));
1803 
1804 	if (unp->un_uppervp != NULLVP)
1805 		return (VOP_ISLOCKED(unp->un_uppervp));
1806 	if (unp->un_lowervp != NULLVP)
1807 		return (VOP_ISLOCKED(unp->un_lowervp));
1808 	return (vop_stdislocked(ap));
1809 }
1810 
1811 static int
1812 unionfs_get_llt_revlock(struct vnode *vp, int flags)
1813 {
1814 	int revlock;
1815 
1816 	revlock = 0;
1817 
1818 	switch (flags & LK_TYPE_MASK) {
1819 	case LK_SHARED:
1820 		if (VOP_ISLOCKED(vp) == LK_EXCLUSIVE)
1821 			revlock = LK_UPGRADE;
1822 		else
1823 			revlock = LK_RELEASE;
1824 		break;
1825 	case LK_EXCLUSIVE:
1826 	case LK_UPGRADE:
1827 		revlock = LK_RELEASE;
1828 		break;
1829 	case LK_DOWNGRADE:
1830 		revlock = LK_UPGRADE;
1831 		break;
1832 	default:
1833 		break;
1834 	}
1835 
1836 	return (revlock);
1837 }
1838 
1839 /*
1840  * The state of an acquired lock is adjusted similarly to
1841  * the time of error generating.
1842  * flags: LK_RELEASE or LK_UPGRADE
1843  */
1844 static void
1845 unionfs_revlock(struct vnode *vp, int flags)
1846 {
1847 	if (flags & LK_RELEASE)
1848 		VOP_UNLOCK_FLAGS(vp, flags);
1849 	else {
1850 		/* UPGRADE */
1851 		if (vn_lock(vp, flags) != 0)
1852 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1853 	}
1854 }
1855 
1856 static int
1857 unionfs_lock(struct vop_lock1_args *ap)
1858 {
1859 	struct mount   *mp;
1860 	struct unionfs_mount *ump;
1861 	struct unionfs_node *unp;
1862 	struct vnode   *vp;
1863 	struct vnode   *uvp;
1864 	struct vnode   *lvp;
1865 	int		error;
1866 	int		flags;
1867 	int		revlock;
1868 	int		interlock;
1869 	int		uhold;
1870 
1871 	KASSERT_UNIONFS_VNODE(ap->a_vp);
1872 
1873 	/*
1874 	 * TODO: rework the unionfs locking scheme.
1875 	 * It's not guaranteed to be safe to blindly lock two vnodes on
1876 	 * different mounts as is done here.  Further, the entanglement
1877 	 * of locking both vnodes with the various options that can be
1878 	 * passed to VOP_LOCK() makes this code hard to reason about.
1879 	 * Instead, consider locking only the upper vnode, or the lower
1880 	 * vnode is the upper is not present, and taking separate measures
1881 	 * to lock both vnodes in the few cases when that is needed.
1882 	 */
1883 	error = 0;
1884 	interlock = 1;
1885 	uhold = 0;
1886 	flags = ap->a_flags;
1887 	vp = ap->a_vp;
1888 
1889 	if (LK_RELEASE == (flags & LK_TYPE_MASK) || !(flags & LK_TYPE_MASK))
1890 		return (VOP_UNLOCK_FLAGS(vp, flags | LK_RELEASE));
1891 
1892 	if ((flags & LK_INTERLOCK) == 0)
1893 		VI_LOCK(vp);
1894 
1895 	mp = vp->v_mount;
1896 	if (mp == NULL)
1897 		goto unionfs_lock_null_vnode;
1898 
1899 	ump = MOUNTTOUNIONFSMOUNT(mp);
1900 	unp = VTOUNIONFS(vp);
1901 	if (ump == NULL || unp == NULL)
1902 		goto unionfs_lock_null_vnode;
1903 	lvp = unp->un_lowervp;
1904 	uvp = unp->un_uppervp;
1905 
1906 	if ((revlock = unionfs_get_llt_revlock(vp, flags)) == 0)
1907 		panic("unknown lock type: 0x%x", flags & LK_TYPE_MASK);
1908 
1909 	if ((vp->v_iflag & VI_OWEINACT) != 0)
1910 		flags |= LK_NOWAIT;
1911 
1912 	/*
1913 	 * Sometimes, lower or upper is already exclusive locked.
1914 	 * (ex. vfs_domount: mounted vnode is already locked.)
1915 	 */
1916 	if ((flags & LK_TYPE_MASK) == LK_EXCLUSIVE &&
1917 	    vp == ump->um_rootvp)
1918 		flags |= LK_CANRECURSE;
1919 
1920 	if (lvp != NULLVP) {
1921 		if (uvp != NULLVP && flags & LK_UPGRADE) {
1922 			/*
1923 			 * Share Lock is once released and a deadlock is
1924 			 * avoided.
1925 			 */
1926 			vholdnz(uvp);
1927 			uhold = 1;
1928 			VOP_UNLOCK(uvp);
1929 			unp = VTOUNIONFS(vp);
1930 			if (unp == NULL) {
1931 				/* vnode is released. */
1932 				VI_UNLOCK(vp);
1933 				VOP_UNLOCK(lvp);
1934 				vdrop(uvp);
1935 				return (EBUSY);
1936 			}
1937 		}
1938 		VI_LOCK_FLAGS(lvp, MTX_DUPOK);
1939 		flags |= LK_INTERLOCK;
1940 		vholdl(lvp);
1941 
1942 		VI_UNLOCK(vp);
1943 		ap->a_flags &= ~LK_INTERLOCK;
1944 
1945 		error = VOP_LOCK(lvp, flags);
1946 
1947 		VI_LOCK(vp);
1948 		unp = VTOUNIONFS(vp);
1949 		if (unp == NULL) {
1950 			/* vnode is released. */
1951 			VI_UNLOCK(vp);
1952 			if (error == 0)
1953 				VOP_UNLOCK(lvp);
1954 			vdrop(lvp);
1955 			if (uhold != 0)
1956 				vdrop(uvp);
1957 			return (vop_stdlock(ap));
1958 		}
1959 	}
1960 
1961 	if (error == 0 && uvp != NULLVP) {
1962 		if (uhold && flags & LK_UPGRADE) {
1963 			flags &= ~LK_TYPE_MASK;
1964 			flags |= LK_EXCLUSIVE;
1965 		}
1966 		VI_LOCK_FLAGS(uvp, MTX_DUPOK);
1967 		flags |= LK_INTERLOCK;
1968 		if (uhold == 0) {
1969 			vholdl(uvp);
1970 			uhold = 1;
1971 		}
1972 
1973 		VI_UNLOCK(vp);
1974 		ap->a_flags &= ~LK_INTERLOCK;
1975 
1976 		error = VOP_LOCK(uvp, flags);
1977 
1978 		VI_LOCK(vp);
1979 		unp = VTOUNIONFS(vp);
1980 		if (unp == NULL) {
1981 			/* vnode is released. */
1982 			VI_UNLOCK(vp);
1983 			if (error == 0)
1984 				VOP_UNLOCK(uvp);
1985 			vdrop(uvp);
1986 			if (lvp != NULLVP) {
1987 				VOP_UNLOCK(lvp);
1988 				vdrop(lvp);
1989 			}
1990 			return (vop_stdlock(ap));
1991 		}
1992 		if (error != 0 && lvp != NULLVP) {
1993 			/* rollback */
1994 			VI_UNLOCK(vp);
1995 			unionfs_revlock(lvp, revlock);
1996 			interlock = 0;
1997 		}
1998 	}
1999 
2000 	if (interlock)
2001 		VI_UNLOCK(vp);
2002 	if (lvp != NULLVP)
2003 		vdrop(lvp);
2004 	if (uhold != 0)
2005 		vdrop(uvp);
2006 
2007 	return (error);
2008 
2009 unionfs_lock_null_vnode:
2010 	ap->a_flags |= LK_INTERLOCK;
2011 	return (vop_stdlock(ap));
2012 }
2013 
2014 static int
2015 unionfs_unlock(struct vop_unlock_args *ap)
2016 {
2017 	struct vnode   *vp;
2018 	struct vnode   *lvp;
2019 	struct vnode   *uvp;
2020 	struct unionfs_node *unp;
2021 	int		error;
2022 	int		uhold;
2023 
2024 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2025 
2026 	error = 0;
2027 	uhold = 0;
2028 	vp = ap->a_vp;
2029 
2030 	unp = VTOUNIONFS(vp);
2031 	if (unp == NULL)
2032 		goto unionfs_unlock_null_vnode;
2033 	lvp = unp->un_lowervp;
2034 	uvp = unp->un_uppervp;
2035 
2036 	if (lvp != NULLVP) {
2037 		vholdnz(lvp);
2038 		error = VOP_UNLOCK(lvp);
2039 	}
2040 
2041 	if (error == 0 && uvp != NULLVP) {
2042 		vholdnz(uvp);
2043 		uhold = 1;
2044 		error = VOP_UNLOCK(uvp);
2045 	}
2046 
2047 	if (lvp != NULLVP)
2048 		vdrop(lvp);
2049 	if (uhold != 0)
2050 		vdrop(uvp);
2051 
2052 	return error;
2053 
2054 unionfs_unlock_null_vnode:
2055 	return (vop_stdunlock(ap));
2056 }
2057 
2058 static int
2059 unionfs_pathconf(struct vop_pathconf_args *ap)
2060 {
2061 	struct unionfs_node *unp;
2062 	struct vnode   *vp;
2063 
2064 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2065 
2066 	unp = VTOUNIONFS(ap->a_vp);
2067 	vp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
2068 
2069 	return (VOP_PATHCONF(vp, ap->a_name, ap->a_retval));
2070 }
2071 
2072 static int
2073 unionfs_advlock(struct vop_advlock_args *ap)
2074 {
2075 	struct unionfs_node *unp;
2076 	struct unionfs_node_status *unsp;
2077 	struct vnode   *vp;
2078 	struct vnode   *uvp;
2079 	struct thread  *td;
2080 	int error;
2081 
2082 	UNIONFS_INTERNAL_DEBUG("unionfs_advlock: enter\n");
2083 
2084 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2085 
2086 	vp = ap->a_vp;
2087 	td = curthread;
2088 
2089 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2090 
2091 	unp = VTOUNIONFS(ap->a_vp);
2092 	uvp = unp->un_uppervp;
2093 
2094 	if (uvp == NULLVP) {
2095 		error = unionfs_copyfile(unp, 1, td->td_ucred, td);
2096 		if (error != 0)
2097 			goto unionfs_advlock_abort;
2098 		uvp = unp->un_uppervp;
2099 
2100 		unionfs_get_node_status(unp, td, &unsp);
2101 		if (unsp->uns_lower_opencnt > 0) {
2102 			/* try reopen the vnode */
2103 			error = VOP_OPEN(uvp, unsp->uns_lower_openmode,
2104 				td->td_ucred, td, NULL);
2105 			if (error)
2106 				goto unionfs_advlock_abort;
2107 			unsp->uns_upper_opencnt++;
2108 			VOP_CLOSE(unp->un_lowervp, unsp->uns_lower_openmode,
2109 			    td->td_ucred, td);
2110 			unsp->uns_lower_opencnt--;
2111 		} else
2112 			unionfs_tryrem_node_status(unp, unsp);
2113 	}
2114 
2115 	VOP_UNLOCK(vp);
2116 
2117 	error = VOP_ADVLOCK(uvp, ap->a_id, ap->a_op, ap->a_fl, ap->a_flags);
2118 
2119 	UNIONFS_INTERNAL_DEBUG("unionfs_advlock: leave (%d)\n", error);
2120 
2121 	return error;
2122 
2123 unionfs_advlock_abort:
2124 	VOP_UNLOCK(vp);
2125 
2126 	UNIONFS_INTERNAL_DEBUG("unionfs_advlock: leave (%d)\n", error);
2127 
2128 	return error;
2129 }
2130 
2131 static int
2132 unionfs_strategy(struct vop_strategy_args *ap)
2133 {
2134 	struct unionfs_node *unp;
2135 	struct vnode   *vp;
2136 
2137 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2138 
2139 	unp = VTOUNIONFS(ap->a_vp);
2140 	vp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
2141 
2142 #ifdef DIAGNOSTIC
2143 	if (vp == NULLVP)
2144 		panic("unionfs_strategy: nullvp");
2145 
2146 	if (ap->a_bp->b_iocmd == BIO_WRITE && vp == unp->un_lowervp)
2147 		panic("unionfs_strategy: writing to lowervp");
2148 #endif
2149 
2150 	return (VOP_STRATEGY(vp, ap->a_bp));
2151 }
2152 
2153 static int
2154 unionfs_getacl(struct vop_getacl_args *ap)
2155 {
2156 	struct unionfs_node *unp;
2157 	struct vnode   *vp;
2158 	int		error;
2159 
2160 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2161 
2162 	unp = VTOUNIONFS(ap->a_vp);
2163 	vp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
2164 
2165 	UNIONFS_INTERNAL_DEBUG("unionfs_getacl: enter\n");
2166 
2167 	error = VOP_GETACL(vp, ap->a_type, ap->a_aclp, ap->a_cred, ap->a_td);
2168 
2169 	UNIONFS_INTERNAL_DEBUG("unionfs_getacl: leave (%d)\n", error);
2170 
2171 	return (error);
2172 }
2173 
2174 static int
2175 unionfs_setacl(struct vop_setacl_args *ap)
2176 {
2177 	struct unionfs_node *unp;
2178 	struct vnode   *uvp;
2179 	struct vnode   *lvp;
2180 	struct thread  *td;
2181 	int		error;
2182 
2183 	UNIONFS_INTERNAL_DEBUG("unionfs_setacl: enter\n");
2184 
2185 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2186 
2187 	error = EROFS;
2188 	unp = VTOUNIONFS(ap->a_vp);
2189 	uvp = unp->un_uppervp;
2190 	lvp = unp->un_lowervp;
2191 	td = ap->a_td;
2192 
2193 	if (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)
2194 		return (EROFS);
2195 
2196 	if (uvp == NULLVP && lvp->v_type == VREG) {
2197 		if ((error = unionfs_copyfile(unp, 1, ap->a_cred, td)) != 0)
2198 			return (error);
2199 		uvp = unp->un_uppervp;
2200 	}
2201 
2202 	if (uvp != NULLVP)
2203 		error = VOP_SETACL(uvp, ap->a_type, ap->a_aclp, ap->a_cred, td);
2204 
2205 	UNIONFS_INTERNAL_DEBUG("unionfs_setacl: leave (%d)\n", error);
2206 
2207 	return (error);
2208 }
2209 
2210 static int
2211 unionfs_aclcheck(struct vop_aclcheck_args *ap)
2212 {
2213 	struct unionfs_node *unp;
2214 	struct vnode   *vp;
2215 	int		error;
2216 
2217 	UNIONFS_INTERNAL_DEBUG("unionfs_aclcheck: enter\n");
2218 
2219 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2220 
2221 	unp = VTOUNIONFS(ap->a_vp);
2222 	vp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
2223 
2224 	error = VOP_ACLCHECK(vp, ap->a_type, ap->a_aclp, ap->a_cred, ap->a_td);
2225 
2226 	UNIONFS_INTERNAL_DEBUG("unionfs_aclcheck: leave (%d)\n", error);
2227 
2228 	return (error);
2229 }
2230 
2231 static int
2232 unionfs_openextattr(struct vop_openextattr_args *ap)
2233 {
2234 	struct unionfs_node *unp;
2235 	struct vnode   *vp;
2236 	struct vnode   *tvp;
2237 	int		error;
2238 
2239 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2240 
2241 	vp = ap->a_vp;
2242 	unp = VTOUNIONFS(vp);
2243 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
2244 
2245 	if ((tvp == unp->un_uppervp && (unp->un_flag & UNIONFS_OPENEXTU)) ||
2246 	    (tvp == unp->un_lowervp && (unp->un_flag & UNIONFS_OPENEXTL)))
2247 		return (EBUSY);
2248 
2249 	error = VOP_OPENEXTATTR(tvp, ap->a_cred, ap->a_td);
2250 
2251 	if (error == 0) {
2252 		if (vn_lock(vp, LK_UPGRADE) != 0)
2253 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2254 		if (tvp == unp->un_uppervp)
2255 			unp->un_flag |= UNIONFS_OPENEXTU;
2256 		else
2257 			unp->un_flag |= UNIONFS_OPENEXTL;
2258 		vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
2259 	}
2260 
2261 	return (error);
2262 }
2263 
2264 static int
2265 unionfs_closeextattr(struct vop_closeextattr_args *ap)
2266 {
2267 	struct unionfs_node *unp;
2268 	struct vnode   *vp;
2269 	struct vnode   *tvp;
2270 	int		error;
2271 
2272 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2273 
2274 	vp = ap->a_vp;
2275 	unp = VTOUNIONFS(vp);
2276 	tvp = NULLVP;
2277 
2278 	if (unp->un_flag & UNIONFS_OPENEXTU)
2279 		tvp = unp->un_uppervp;
2280 	else if (unp->un_flag & UNIONFS_OPENEXTL)
2281 		tvp = unp->un_lowervp;
2282 
2283 	if (tvp == NULLVP)
2284 		return (EOPNOTSUPP);
2285 
2286 	error = VOP_CLOSEEXTATTR(tvp, ap->a_commit, ap->a_cred, ap->a_td);
2287 
2288 	if (error == 0) {
2289 		if (vn_lock(vp, LK_UPGRADE) != 0)
2290 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2291 		if (tvp == unp->un_uppervp)
2292 			unp->un_flag &= ~UNIONFS_OPENEXTU;
2293 		else
2294 			unp->un_flag &= ~UNIONFS_OPENEXTL;
2295 		vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
2296 	}
2297 
2298 	return (error);
2299 }
2300 
2301 static int
2302 unionfs_getextattr(struct vop_getextattr_args *ap)
2303 {
2304 	struct unionfs_node *unp;
2305 	struct vnode   *vp;
2306 
2307 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2308 
2309 	unp = VTOUNIONFS(ap->a_vp);
2310 	vp = NULLVP;
2311 
2312 	if (unp->un_flag & UNIONFS_OPENEXTU)
2313 		vp = unp->un_uppervp;
2314 	else if (unp->un_flag & UNIONFS_OPENEXTL)
2315 		vp = unp->un_lowervp;
2316 
2317 	if (vp == NULLVP)
2318 		return (EOPNOTSUPP);
2319 
2320 	return (VOP_GETEXTATTR(vp, ap->a_attrnamespace, ap->a_name,
2321 	    ap->a_uio, ap->a_size, ap->a_cred, ap->a_td));
2322 }
2323 
2324 static int
2325 unionfs_setextattr(struct vop_setextattr_args *ap)
2326 {
2327 	struct unionfs_node *unp;
2328 	struct vnode   *uvp;
2329 	struct vnode   *lvp;
2330 	struct vnode   *ovp;
2331 	struct ucred   *cred;
2332 	struct thread  *td;
2333 	int		error;
2334 
2335 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2336 
2337 	error = EROFS;
2338 	unp = VTOUNIONFS(ap->a_vp);
2339 	uvp = unp->un_uppervp;
2340 	lvp = unp->un_lowervp;
2341 	ovp = NULLVP;
2342 	cred = ap->a_cred;
2343 	td = ap->a_td;
2344 
2345 	UNIONFS_INTERNAL_DEBUG("unionfs_setextattr: enter (un_flag=%x)\n",
2346 	    unp->un_flag);
2347 
2348 	if (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)
2349 		return (EROFS);
2350 
2351 	if (unp->un_flag & UNIONFS_OPENEXTU)
2352 		ovp = unp->un_uppervp;
2353 	else if (unp->un_flag & UNIONFS_OPENEXTL)
2354 		ovp = unp->un_lowervp;
2355 
2356 	if (ovp == NULLVP)
2357 		return (EOPNOTSUPP);
2358 
2359 	if (ovp == lvp && lvp->v_type == VREG) {
2360 		VOP_CLOSEEXTATTR(lvp, 0, cred, td);
2361 		if (uvp == NULLVP &&
2362 		    (error = unionfs_copyfile(unp, 1, cred, td)) != 0) {
2363 unionfs_setextattr_reopen:
2364 			if ((unp->un_flag & UNIONFS_OPENEXTL) &&
2365 			    VOP_OPENEXTATTR(lvp, cred, td)) {
2366 #ifdef DIAGNOSTIC
2367 				panic("unionfs: VOP_OPENEXTATTR failed");
2368 #endif
2369 				unp->un_flag &= ~UNIONFS_OPENEXTL;
2370 			}
2371 			goto unionfs_setextattr_abort;
2372 		}
2373 		uvp = unp->un_uppervp;
2374 		if ((error = VOP_OPENEXTATTR(uvp, cred, td)) != 0)
2375 			goto unionfs_setextattr_reopen;
2376 		unp->un_flag &= ~UNIONFS_OPENEXTL;
2377 		unp->un_flag |= UNIONFS_OPENEXTU;
2378 		ovp = uvp;
2379 	}
2380 
2381 	if (ovp == uvp)
2382 		error = VOP_SETEXTATTR(ovp, ap->a_attrnamespace, ap->a_name,
2383 		    ap->a_uio, cred, td);
2384 
2385 unionfs_setextattr_abort:
2386 	UNIONFS_INTERNAL_DEBUG("unionfs_setextattr: leave (%d)\n", error);
2387 
2388 	return (error);
2389 }
2390 
2391 static int
2392 unionfs_listextattr(struct vop_listextattr_args *ap)
2393 {
2394 	struct unionfs_node *unp;
2395 	struct vnode *vp;
2396 
2397 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2398 
2399 	unp = VTOUNIONFS(ap->a_vp);
2400 	vp = NULLVP;
2401 
2402 	if (unp->un_flag & UNIONFS_OPENEXTU)
2403 		vp = unp->un_uppervp;
2404 	else if (unp->un_flag & UNIONFS_OPENEXTL)
2405 		vp = unp->un_lowervp;
2406 
2407 	if (vp == NULLVP)
2408 		return (EOPNOTSUPP);
2409 
2410 	return (VOP_LISTEXTATTR(vp, ap->a_attrnamespace, ap->a_uio,
2411 	    ap->a_size, ap->a_cred, ap->a_td));
2412 }
2413 
2414 static int
2415 unionfs_deleteextattr(struct vop_deleteextattr_args *ap)
2416 {
2417 	struct unionfs_node *unp;
2418 	struct vnode   *uvp;
2419 	struct vnode   *lvp;
2420 	struct vnode   *ovp;
2421 	struct ucred   *cred;
2422 	struct thread  *td;
2423 	int		error;
2424 
2425 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2426 
2427 	error = EROFS;
2428 	unp = VTOUNIONFS(ap->a_vp);
2429 	uvp = unp->un_uppervp;
2430 	lvp = unp->un_lowervp;
2431 	ovp = NULLVP;
2432 	cred = ap->a_cred;
2433 	td = ap->a_td;
2434 
2435 	UNIONFS_INTERNAL_DEBUG("unionfs_deleteextattr: enter (un_flag=%x)\n",
2436 	    unp->un_flag);
2437 
2438 	if (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)
2439 		return (EROFS);
2440 
2441 	if (unp->un_flag & UNIONFS_OPENEXTU)
2442 		ovp = unp->un_uppervp;
2443 	else if (unp->un_flag & UNIONFS_OPENEXTL)
2444 		ovp = unp->un_lowervp;
2445 
2446 	if (ovp == NULLVP)
2447 		return (EOPNOTSUPP);
2448 
2449 	if (ovp == lvp && lvp->v_type == VREG) {
2450 		VOP_CLOSEEXTATTR(lvp, 0, cred, td);
2451 		if (uvp == NULLVP &&
2452 		    (error = unionfs_copyfile(unp, 1, cred, td)) != 0) {
2453 unionfs_deleteextattr_reopen:
2454 			if ((unp->un_flag & UNIONFS_OPENEXTL) &&
2455 			    VOP_OPENEXTATTR(lvp, cred, td)) {
2456 #ifdef DIAGNOSTIC
2457 				panic("unionfs: VOP_OPENEXTATTR failed");
2458 #endif
2459 				unp->un_flag &= ~UNIONFS_OPENEXTL;
2460 			}
2461 			goto unionfs_deleteextattr_abort;
2462 		}
2463 		uvp = unp->un_uppervp;
2464 		if ((error = VOP_OPENEXTATTR(uvp, cred, td)) != 0)
2465 			goto unionfs_deleteextattr_reopen;
2466 		unp->un_flag &= ~UNIONFS_OPENEXTL;
2467 		unp->un_flag |= UNIONFS_OPENEXTU;
2468 		ovp = uvp;
2469 	}
2470 
2471 	if (ovp == uvp)
2472 		error = VOP_DELETEEXTATTR(ovp, ap->a_attrnamespace, ap->a_name,
2473 		    ap->a_cred, ap->a_td);
2474 
2475 unionfs_deleteextattr_abort:
2476 	UNIONFS_INTERNAL_DEBUG("unionfs_deleteextattr: leave (%d)\n", error);
2477 
2478 	return (error);
2479 }
2480 
2481 static int
2482 unionfs_setlabel(struct vop_setlabel_args *ap)
2483 {
2484 	struct unionfs_node *unp;
2485 	struct vnode   *uvp;
2486 	struct vnode   *lvp;
2487 	struct thread  *td;
2488 	int		error;
2489 
2490 	UNIONFS_INTERNAL_DEBUG("unionfs_setlabel: enter\n");
2491 
2492 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2493 
2494 	error = EROFS;
2495 	unp = VTOUNIONFS(ap->a_vp);
2496 	uvp = unp->un_uppervp;
2497 	lvp = unp->un_lowervp;
2498 	td = ap->a_td;
2499 
2500 	if (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)
2501 		return (EROFS);
2502 
2503 	if (uvp == NULLVP && lvp->v_type == VREG) {
2504 		if ((error = unionfs_copyfile(unp, 1, ap->a_cred, td)) != 0)
2505 			return (error);
2506 		uvp = unp->un_uppervp;
2507 	}
2508 
2509 	if (uvp != NULLVP)
2510 		error = VOP_SETLABEL(uvp, ap->a_label, ap->a_cred, td);
2511 
2512 	UNIONFS_INTERNAL_DEBUG("unionfs_setlabel: leave (%d)\n", error);
2513 
2514 	return (error);
2515 }
2516 
2517 static int
2518 unionfs_vptofh(struct vop_vptofh_args *ap)
2519 {
2520 	return (EOPNOTSUPP);
2521 }
2522 
2523 static int
2524 unionfs_add_writecount(struct vop_add_writecount_args *ap)
2525 {
2526 	struct vnode *tvp, *vp;
2527 	struct unionfs_node *unp;
2528 	int error, writerefs;
2529 
2530 	vp = ap->a_vp;
2531 	unp = VTOUNIONFS(vp);
2532 	tvp = unp->un_uppervp;
2533 	KASSERT(tvp != NULL,
2534 	    ("%s: adding write ref without upper vnode", __func__));
2535 	error = VOP_ADD_WRITECOUNT(tvp, ap->a_inc);
2536 	if (error != 0)
2537 		return (error);
2538 	/*
2539 	 * We need to track the write refs we've passed to the underlying
2540 	 * vnodes so that we can undo them in case we are forcibly unmounted.
2541 	 */
2542 	writerefs = atomic_fetchadd_int(&vp->v_writecount, ap->a_inc);
2543 	/* text refs are bypassed to lowervp */
2544 	VNASSERT(writerefs >= 0, vp,
2545 	    ("%s: invalid write count %d", __func__, writerefs));
2546 	VNASSERT(writerefs + ap->a_inc >= 0, vp,
2547 	    ("%s: invalid write count inc %d + %d", __func__,
2548 	    writerefs, ap->a_inc));
2549 	return (0);
2550 }
2551 
2552 static int
2553 unionfs_vput_pair(struct vop_vput_pair_args *ap)
2554 {
2555 	struct mount *mp;
2556 	struct vnode *dvp, *vp, **vpp, *lvp, *ldvp, *uvp, *udvp, *tempvp;
2557 	struct unionfs_node *dunp, *unp;
2558 	int error, res;
2559 
2560 	dvp = ap->a_dvp;
2561 	vpp = ap->a_vpp;
2562 	vp = NULLVP;
2563 	lvp = NULLVP;
2564 	uvp = NULLVP;
2565 	unp = NULL;
2566 
2567 	dunp = VTOUNIONFS(dvp);
2568 	udvp = dunp->un_uppervp;
2569 	ldvp = dunp->un_lowervp;
2570 
2571 	/*
2572 	 * Underlying vnodes should be locked because the encompassing unionfs
2573 	 * node is locked, but will not be referenced, as the reference will
2574 	 * only be on the unionfs node.  Reference them now so that the vput()s
2575 	 * performed by VOP_VPUT_PAIR() will have a reference to drop.
2576 	 */
2577 	if (udvp != NULLVP)
2578 		vref(udvp);
2579 	if (ldvp != NULLVP)
2580 		vref(ldvp);
2581 
2582 	if (vpp != NULL)
2583 		vp = *vpp;
2584 
2585 	if (vp != NULLVP) {
2586 		unp = VTOUNIONFS(vp);
2587 		uvp = unp->un_uppervp;
2588 		lvp = unp->un_lowervp;
2589 		if (uvp != NULLVP)
2590 			vref(uvp);
2591 		if (lvp != NULLVP)
2592 			vref(lvp);
2593 
2594 		/*
2595 		 * If we're being asked to return a locked child vnode, then
2596 		 * we may need to create a replacement vnode in case the
2597 		 * original is reclaimed while the lock is dropped.  In that
2598 		 * case we'll need to ensure the mount and the underlying
2599 		 * vnodes aren't also recycled during that window.
2600 		 */
2601 		if (!ap->a_unlock_vp) {
2602 			vhold(vp);
2603 			if (uvp != NULLVP)
2604 				vhold(uvp);
2605 			if (lvp != NULLVP)
2606 				vhold(lvp);
2607 			mp = vp->v_mount;
2608 			vfs_ref(mp);
2609 		}
2610 	}
2611 
2612 	/*
2613 	 * TODO: Because unionfs_lock() locks both the lower and upper vnodes
2614 	 * (if available), we must also call VOP_VPUT_PAIR() on both the lower
2615 	 * and upper parent/child pairs.  If unionfs_lock() is reworked to lock
2616 	 * only a single vnode, this code will need to change to also only
2617 	 * operate on one vnode pair.
2618 	 */
2619 	ASSERT_VOP_LOCKED(ldvp, __func__);
2620 	ASSERT_VOP_LOCKED(udvp, __func__);
2621 	ASSERT_VOP_LOCKED(lvp, __func__);
2622 	ASSERT_VOP_LOCKED(uvp, __func__);
2623 
2624 	KASSERT(lvp == NULLVP || ldvp != NULLVP,
2625 	    ("%s: NULL ldvp with non-NULL lvp", __func__));
2626 	if (ldvp != NULLVP)
2627 		res = VOP_VPUT_PAIR(ldvp, lvp != NULLVP ? &lvp : NULL, true);
2628 	KASSERT(uvp == NULLVP || udvp != NULLVP,
2629 	    ("%s: NULL udvp with non-NULL uvp", __func__));
2630 	if (udvp != NULLVP)
2631 		res = VOP_VPUT_PAIR(udvp, uvp != NULLVP ? &uvp : NULL, true);
2632 
2633 	ASSERT_VOP_UNLOCKED(ldvp, __func__);
2634 	ASSERT_VOP_UNLOCKED(udvp, __func__);
2635 	ASSERT_VOP_UNLOCKED(lvp, __func__);
2636 	ASSERT_VOP_UNLOCKED(uvp, __func__);
2637 
2638 	/*
2639 	 * VOP_VPUT_PAIR() dropped the references we added to the underlying
2640 	 * vnodes, now drop the caller's reference to the unionfs vnodes.
2641 	 */
2642 	if (vp != NULLVP && ap->a_unlock_vp)
2643 		vrele(vp);
2644 	vrele(dvp);
2645 
2646 	if (vp == NULLVP || ap->a_unlock_vp)
2647 		return (res);
2648 
2649 	/*
2650 	 * We're being asked to return a locked vnode.  At this point, the
2651 	 * underlying vnodes have been unlocked, so vp may have been reclaimed.
2652 	 */
2653 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2654 	if (vp->v_data == NULL && vfs_busy(mp, MBF_NOWAIT) == 0) {
2655 		vput(vp);
2656 		error = unionfs_nodeget(mp, uvp, lvp, dvp, &tempvp, NULL);
2657 		if (error == 0) {
2658 			vn_lock(tempvp, LK_EXCLUSIVE | LK_RETRY);
2659 			*vpp = tempvp;
2660 		} else
2661 			vget(vp, LK_EXCLUSIVE | LK_RETRY);
2662 		vfs_unbusy(mp);
2663 	}
2664 	if (lvp != NULLVP)
2665 		vdrop(lvp);
2666 	if (uvp != NULLVP)
2667 		vdrop(uvp);
2668 	vdrop(vp);
2669 	vfs_rel(mp);
2670 
2671 	return (res);
2672 }
2673 
2674 static int
2675 unionfs_set_text(struct vop_set_text_args *ap)
2676 {
2677 	struct vnode *tvp;
2678 	struct unionfs_node *unp;
2679 	int error;
2680 
2681 	/*
2682 	 * We assume text refs are managed against lvp/uvp through the
2683 	 * executable mapping backed by its VM object.  We therefore don't
2684 	 * need to track leased text refs in the case of a forcible unmount.
2685 	 */
2686 	unp = VTOUNIONFS(ap->a_vp);
2687 	ASSERT_VOP_LOCKED(ap->a_vp, __func__);
2688 	tvp = unp->un_uppervp != NULL ? unp->un_uppervp : unp->un_lowervp;
2689 	error = VOP_SET_TEXT(tvp);
2690 	return (error);
2691 }
2692 
2693 static int
2694 unionfs_unset_text(struct vop_unset_text_args *ap)
2695 {
2696 	struct vnode *tvp;
2697 	struct unionfs_node *unp;
2698 
2699 	ASSERT_VOP_LOCKED(ap->a_vp, __func__);
2700 	unp = VTOUNIONFS(ap->a_vp);
2701 	tvp = unp->un_uppervp != NULL ? unp->un_uppervp : unp->un_lowervp;
2702 	VOP_UNSET_TEXT_CHECKED(tvp);
2703 	return (0);
2704 }
2705 
2706 struct vop_vector unionfs_vnodeops = {
2707 	.vop_default =		&default_vnodeops,
2708 
2709 	.vop_access =		unionfs_access,
2710 	.vop_aclcheck =		unionfs_aclcheck,
2711 	.vop_advlock =		unionfs_advlock,
2712 	.vop_bmap =		VOP_EOPNOTSUPP,
2713 	.vop_cachedlookup =	unionfs_lookup,
2714 	.vop_close =		unionfs_close,
2715 	.vop_closeextattr =	unionfs_closeextattr,
2716 	.vop_create =		unionfs_create,
2717 	.vop_deleteextattr =	unionfs_deleteextattr,
2718 	.vop_fsync =		unionfs_fsync,
2719 	.vop_getacl =		unionfs_getacl,
2720 	.vop_getattr =		unionfs_getattr,
2721 	.vop_getextattr =	unionfs_getextattr,
2722 	.vop_getwritemount =	unionfs_getwritemount,
2723 	.vop_inactive =		unionfs_inactive,
2724 	.vop_need_inactive =	vop_stdneed_inactive,
2725 	.vop_islocked =		unionfs_islocked,
2726 	.vop_ioctl =		unionfs_ioctl,
2727 	.vop_link =		unionfs_link,
2728 	.vop_listextattr =	unionfs_listextattr,
2729 	.vop_lock1 =		unionfs_lock,
2730 	.vop_lookup =		vfs_cache_lookup,
2731 	.vop_mkdir =		unionfs_mkdir,
2732 	.vop_mknod =		unionfs_mknod,
2733 	.vop_open =		unionfs_open,
2734 	.vop_openextattr =	unionfs_openextattr,
2735 	.vop_pathconf =		unionfs_pathconf,
2736 	.vop_poll =		unionfs_poll,
2737 	.vop_print =		unionfs_print,
2738 	.vop_read =		unionfs_read,
2739 	.vop_readdir =		unionfs_readdir,
2740 	.vop_readlink =		unionfs_readlink,
2741 	.vop_reclaim =		unionfs_reclaim,
2742 	.vop_remove =		unionfs_remove,
2743 	.vop_rename =		unionfs_rename,
2744 	.vop_rmdir =		unionfs_rmdir,
2745 	.vop_setacl =		unionfs_setacl,
2746 	.vop_setattr =		unionfs_setattr,
2747 	.vop_setextattr =	unionfs_setextattr,
2748 	.vop_setlabel =		unionfs_setlabel,
2749 	.vop_strategy =		unionfs_strategy,
2750 	.vop_symlink =		unionfs_symlink,
2751 	.vop_unlock =		unionfs_unlock,
2752 	.vop_whiteout =		unionfs_whiteout,
2753 	.vop_write =		unionfs_write,
2754 	.vop_vptofh =		unionfs_vptofh,
2755 	.vop_add_writecount =	unionfs_add_writecount,
2756 	.vop_vput_pair =	unionfs_vput_pair,
2757 	.vop_set_text =		unionfs_set_text,
2758 	.vop_unset_text = 	unionfs_unset_text,
2759 };
2760 VFS_VOP_VECTOR_REGISTER(unionfs_vnodeops);
2761