xref: /freebsd/sys/fs/unionfs/union_vnops.c (revision 6419bb52)
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 <vm/vm.h>
65 #include <vm/vm_extern.h>
66 #include <vm/vm_object.h>
67 #include <vm/vnode_pager.h>
68 
69 #if 0
70 #define UNIONFS_INTERNAL_DEBUG(msg, args...)    printf(msg, ## args)
71 #define UNIONFS_IDBG_RENAME
72 #else
73 #define UNIONFS_INTERNAL_DEBUG(msg, args...)
74 #endif
75 
76 #define KASSERT_UNIONFS_VNODE(vp) \
77 	KASSERT(((vp)->v_op == &unionfs_vnodeops), \
78 	    ("unionfs: it is not unionfs-vnode"))
79 
80 static int
81 unionfs_lookup(struct vop_cachedlookup_args *ap)
82 {
83 	int		iswhiteout;
84 	int		lockflag;
85 	int		error , uerror, lerror;
86 	u_long		nameiop;
87 	u_long		cnflags, cnflagsbk;
88 	struct unionfs_node *dunp;
89 	struct vnode   *dvp, *udvp, *ldvp, *vp, *uvp, *lvp, *dtmpvp;
90 	struct vattr	va;
91 	struct componentname *cnp;
92 	struct thread  *td;
93 
94 	iswhiteout = 0;
95 	lockflag = 0;
96 	error = uerror = lerror = ENOENT;
97 	cnp = ap->a_cnp;
98 	nameiop = cnp->cn_nameiop;
99 	cnflags = cnp->cn_flags;
100 	dvp = ap->a_dvp;
101 	dunp = VTOUNIONFS(dvp);
102 	udvp = dunp->un_uppervp;
103 	ldvp = dunp->un_lowervp;
104 	vp = uvp = lvp = NULLVP;
105 	td = curthread;
106 	*(ap->a_vpp) = NULLVP;
107 
108 	UNIONFS_INTERNAL_DEBUG("unionfs_lookup: enter: nameiop=%ld, flags=%lx, path=%s\n", nameiop, cnflags, cnp->cn_nameptr);
109 
110 	if (dvp->v_type != VDIR)
111 		return (ENOTDIR);
112 
113 	/*
114 	 * If read-only and op is not LOOKUP, will return EROFS.
115 	 */
116 	if ((cnflags & ISLASTCN) &&
117 	    (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
118 	    LOOKUP != nameiop)
119 		return (EROFS);
120 
121 	/*
122 	 * lookup dotdot
123 	 */
124 	if (cnflags & ISDOTDOT) {
125 		if (LOOKUP != nameiop && udvp == NULLVP)
126 			return (EROFS);
127 
128 		if (udvp != NULLVP) {
129 			dtmpvp = udvp;
130 			if (ldvp != NULLVP)
131 				VOP_UNLOCK(ldvp);
132 		}
133 		else
134 			dtmpvp = ldvp;
135 
136 		error = VOP_LOOKUP(dtmpvp, &vp, cnp);
137 
138 		if (dtmpvp == udvp && ldvp != NULLVP) {
139 			VOP_UNLOCK(udvp);
140 			vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
141 		}
142 
143 		if (error == 0) {
144 			/*
145 			 * Exchange lock and reference from vp to
146 			 * dunp->un_dvp. vp is upper/lower vnode, but it
147 			 * will need to return the unionfs vnode.
148 			 */
149 			if (nameiop == DELETE  || nameiop == RENAME ||
150 			    (cnp->cn_lkflags & LK_TYPE_MASK))
151 				VOP_UNLOCK(vp);
152 			vrele(vp);
153 
154 			VOP_UNLOCK(dvp);
155 			*(ap->a_vpp) = dunp->un_dvp;
156 			vref(dunp->un_dvp);
157 
158 			if (nameiop == DELETE || nameiop == RENAME)
159 				vn_lock(dunp->un_dvp, LK_EXCLUSIVE | LK_RETRY);
160 			else if (cnp->cn_lkflags & LK_TYPE_MASK)
161 				vn_lock(dunp->un_dvp, cnp->cn_lkflags |
162 				    LK_RETRY);
163 
164 			vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY);
165 		} else if (error == ENOENT && (cnflags & MAKEENTRY) != 0)
166 			cache_enter(dvp, NULLVP, cnp);
167 
168 		UNIONFS_INTERNAL_DEBUG("unionfs_lookup: leave (%d)\n", error);
169 
170 		return (error);
171 	}
172 
173 	/*
174 	 * lookup upper layer
175 	 */
176 	if (udvp != NULLVP) {
177 		uerror = VOP_LOOKUP(udvp, &uvp, cnp);
178 
179 		if (uerror == 0) {
180 			if (udvp == uvp) {	/* is dot */
181 				vrele(uvp);
182 				*(ap->a_vpp) = dvp;
183 				vref(dvp);
184 
185 				UNIONFS_INTERNAL_DEBUG("unionfs_lookup: leave (%d)\n", uerror);
186 
187 				return (uerror);
188 			}
189 			if (nameiop == DELETE || nameiop == RENAME ||
190 			    (cnp->cn_lkflags & LK_TYPE_MASK))
191 				VOP_UNLOCK(uvp);
192 		}
193 
194 		/* check whiteout */
195 		if (uerror == ENOENT || uerror == EJUSTRETURN)
196 			if (cnp->cn_flags & ISWHITEOUT)
197 				iswhiteout = 1;	/* don't lookup lower */
198 		if (iswhiteout == 0 && ldvp != NULLVP)
199 			if (!VOP_GETATTR(udvp, &va, cnp->cn_cred) &&
200 			    (va.va_flags & OPAQUE))
201 				iswhiteout = 1;	/* don't lookup lower */
202 #if 0
203 		UNIONFS_INTERNAL_DEBUG("unionfs_lookup: debug: whiteout=%d, path=%s\n", iswhiteout, cnp->cn_nameptr);
204 #endif
205 	}
206 
207 	/*
208 	 * lookup lower layer
209 	 */
210 	if (ldvp != NULLVP && !(cnflags & DOWHITEOUT) && iswhiteout == 0) {
211 		/* always op is LOOKUP */
212 		cnp->cn_nameiop = LOOKUP;
213 		cnflagsbk = cnp->cn_flags;
214 		cnp->cn_flags = cnflags;
215 
216 		lerror = VOP_LOOKUP(ldvp, &lvp, cnp);
217 
218 		cnp->cn_nameiop = nameiop;
219 		if (udvp != NULLVP && (uerror == 0 || uerror == EJUSTRETURN))
220 			cnp->cn_flags = cnflagsbk;
221 
222 		if (lerror == 0) {
223 			if (ldvp == lvp) {	/* is dot */
224 				if (uvp != NULLVP)
225 					vrele(uvp);	/* no need? */
226 				vrele(lvp);
227 				*(ap->a_vpp) = dvp;
228 				vref(dvp);
229 
230 				UNIONFS_INTERNAL_DEBUG("unionfs_lookup: leave (%d)\n", lerror);
231 
232 				return (lerror);
233 			}
234 			if (cnp->cn_lkflags & LK_TYPE_MASK)
235 				VOP_UNLOCK(lvp);
236 		}
237 	}
238 
239 	/*
240 	 * check lookup result
241 	 */
242 	if (uvp == NULLVP && lvp == NULLVP) {
243 		UNIONFS_INTERNAL_DEBUG("unionfs_lookup: leave (%d)\n",
244 		    (udvp != NULLVP ? uerror : lerror));
245 		return (udvp != NULLVP ? uerror : lerror);
246 	}
247 
248 	/*
249 	 * check vnode type
250 	 */
251 	if (uvp != NULLVP && lvp != NULLVP && uvp->v_type != lvp->v_type) {
252 		vrele(lvp);
253 		lvp = NULLVP;
254 	}
255 
256 	/*
257 	 * check shadow dir
258 	 */
259 	if (uerror != 0 && uerror != EJUSTRETURN && udvp != NULLVP &&
260 	    lerror == 0 && lvp != NULLVP && lvp->v_type == VDIR &&
261 	    !(dvp->v_mount->mnt_flag & MNT_RDONLY) &&
262 	    (1 < cnp->cn_namelen || '.' != *(cnp->cn_nameptr))) {
263 		/* get unionfs vnode in order to create a new shadow dir. */
264 		error = unionfs_nodeget(dvp->v_mount, NULLVP, lvp, dvp, &vp,
265 		    cnp, td);
266 		if (error != 0)
267 			goto unionfs_lookup_out;
268 
269 		if (LK_SHARED == (cnp->cn_lkflags & LK_TYPE_MASK))
270 			VOP_UNLOCK(vp);
271 		if (LK_EXCLUSIVE != VOP_ISLOCKED(vp)) {
272 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
273 			lockflag = 1;
274 		}
275 		error = unionfs_mkshadowdir(MOUNTTOUNIONFSMOUNT(dvp->v_mount),
276 		    udvp, VTOUNIONFS(vp), cnp, td);
277 		if (lockflag != 0)
278 			VOP_UNLOCK(vp);
279 		if (error != 0) {
280 			UNIONFSDEBUG("unionfs_lookup: Unable to create shadow dir.");
281 			if ((cnp->cn_lkflags & LK_TYPE_MASK) == LK_EXCLUSIVE)
282 				vput(vp);
283 			else
284 				vrele(vp);
285 			goto unionfs_lookup_out;
286 		}
287 		if ((cnp->cn_lkflags & LK_TYPE_MASK) == LK_SHARED)
288 			vn_lock(vp, LK_SHARED | LK_RETRY);
289 	}
290 	/*
291 	 * get unionfs vnode.
292 	 */
293 	else {
294 		if (uvp != NULLVP)
295 			error = uerror;
296 		else
297 			error = lerror;
298 		if (error != 0)
299 			goto unionfs_lookup_out;
300 		/*
301 		 * get socket vnode.
302 		 */
303 		if (uvp != NULLVP && uvp->v_type == VSOCK) {
304 			vp = uvp;
305 			vref(vp);
306 			if (cnp->cn_lkflags & LK_TYPE_MASK)
307 				vn_lock(vp, cnp->cn_lkflags | LK_RETRY);
308 		}
309 		else if (lvp != NULLVP && lvp->v_type == VSOCK) {
310 			vp = lvp;
311 			vref(vp);
312 			if (cnp->cn_lkflags & LK_TYPE_MASK)
313 				vn_lock(vp, cnp->cn_lkflags | LK_RETRY);
314 		}
315 		/*
316 		 * get unionfs vnode.
317 		 */
318 		else
319 			error = unionfs_nodeget(dvp->v_mount, uvp, lvp,
320 			    dvp, &vp, cnp, td);
321 		if (error != 0) {
322 			UNIONFSDEBUG("unionfs_lookup: Unable to create unionfs vnode.");
323 			goto unionfs_lookup_out;
324 		}
325 		if ((nameiop == DELETE || nameiop == RENAME) &&
326 		    (cnp->cn_lkflags & LK_TYPE_MASK) == 0)
327 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
328 	}
329 
330 	*(ap->a_vpp) = vp;
331 
332 	if ((cnflags & MAKEENTRY) && vp->v_type != VSOCK)
333 		cache_enter(dvp, vp, cnp);
334 
335 unionfs_lookup_out:
336 	if (uvp != NULLVP)
337 		vrele(uvp);
338 	if (lvp != NULLVP)
339 		vrele(lvp);
340 
341 	if (error == ENOENT && (cnflags & MAKEENTRY) != 0)
342 		cache_enter(dvp, NULLVP, cnp);
343 
344 	UNIONFS_INTERNAL_DEBUG("unionfs_lookup: leave (%d)\n", error);
345 
346 	return (error);
347 }
348 
349 static int
350 unionfs_create(struct vop_create_args *ap)
351 {
352 	struct unionfs_node *dunp;
353 	struct componentname *cnp;
354 	struct vnode   *udvp;
355 	struct vnode   *vp;
356 	int		error;
357 
358 	UNIONFS_INTERNAL_DEBUG("unionfs_create: enter\n");
359 
360 	KASSERT_UNIONFS_VNODE(ap->a_dvp);
361 
362 	dunp = VTOUNIONFS(ap->a_dvp);
363 	cnp = ap->a_cnp;
364 	udvp = dunp->un_uppervp;
365 	error = EROFS;
366 
367 	if (udvp != NULLVP) {
368 		error = VOP_CREATE(udvp, &vp, cnp, ap->a_vap);
369 		if (error != 0)
370 			goto unionfs_create_abort;
371 
372 		if (vp->v_type == VSOCK)
373 			*(ap->a_vpp) = vp;
374 		else {
375 			VOP_UNLOCK(vp);
376 			error = unionfs_nodeget(ap->a_dvp->v_mount, vp, NULLVP,
377 			    ap->a_dvp, ap->a_vpp, cnp, curthread);
378 			vrele(vp);
379 		}
380 	}
381 
382 unionfs_create_abort:
383 	UNIONFS_INTERNAL_DEBUG("unionfs_create: leave (%d)\n", error);
384 
385 	return (error);
386 }
387 
388 static int
389 unionfs_whiteout(struct vop_whiteout_args *ap)
390 {
391 	struct unionfs_node *dunp;
392 	struct componentname *cnp;
393 	struct vnode   *udvp;
394 	int		error;
395 
396 	UNIONFS_INTERNAL_DEBUG("unionfs_whiteout: enter\n");
397 
398 	KASSERT_UNIONFS_VNODE(ap->a_dvp);
399 
400 	dunp = VTOUNIONFS(ap->a_dvp);
401 	cnp = ap->a_cnp;
402 	udvp = dunp->un_uppervp;
403 	error = EOPNOTSUPP;
404 
405 	if (udvp != NULLVP) {
406 		switch (ap->a_flags) {
407 		case CREATE:
408 		case DELETE:
409 		case LOOKUP:
410 			error = VOP_WHITEOUT(udvp, cnp, ap->a_flags);
411 			break;
412 		default:
413 			error = EINVAL;
414 			break;
415 		}
416 	}
417 
418 	UNIONFS_INTERNAL_DEBUG("unionfs_whiteout: leave (%d)\n", error);
419 
420 	return (error);
421 }
422 
423 static int
424 unionfs_mknod(struct vop_mknod_args *ap)
425 {
426 	struct unionfs_node *dunp;
427 	struct componentname *cnp;
428 	struct vnode   *udvp;
429 	struct vnode   *vp;
430 	int		error;
431 
432 	UNIONFS_INTERNAL_DEBUG("unionfs_mknod: enter\n");
433 
434 	KASSERT_UNIONFS_VNODE(ap->a_dvp);
435 
436 	dunp = VTOUNIONFS(ap->a_dvp);
437 	cnp = ap->a_cnp;
438 	udvp = dunp->un_uppervp;
439 	error = EROFS;
440 
441 	if (udvp != NULLVP) {
442 		error = VOP_MKNOD(udvp, &vp, cnp, ap->a_vap);
443 		if (error != 0)
444 			goto unionfs_mknod_abort;
445 
446 		if (vp->v_type == VSOCK)
447 			*(ap->a_vpp) = vp;
448 		else {
449 			VOP_UNLOCK(vp);
450 			error = unionfs_nodeget(ap->a_dvp->v_mount, vp, NULLVP,
451 			    ap->a_dvp, ap->a_vpp, cnp, curthread);
452 			vrele(vp);
453 		}
454 	}
455 
456 unionfs_mknod_abort:
457 	UNIONFS_INTERNAL_DEBUG("unionfs_mknod: leave (%d)\n", error);
458 
459 	return (error);
460 }
461 
462 static int
463 unionfs_open(struct vop_open_args *ap)
464 {
465 	int		error;
466 	struct unionfs_node *unp;
467 	struct unionfs_node_status *unsp;
468 	struct vnode   *uvp;
469 	struct vnode   *lvp;
470 	struct vnode   *targetvp;
471 	struct ucred   *cred;
472 	struct thread  *td;
473 
474 	UNIONFS_INTERNAL_DEBUG("unionfs_open: enter\n");
475 
476 	KASSERT_UNIONFS_VNODE(ap->a_vp);
477 
478 	error = 0;
479 	unp = VTOUNIONFS(ap->a_vp);
480 	uvp = unp->un_uppervp;
481 	lvp = unp->un_lowervp;
482 	targetvp = NULLVP;
483 	cred = ap->a_cred;
484 	td = ap->a_td;
485 
486 	unionfs_get_node_status(unp, td, &unsp);
487 
488 	if (unsp->uns_lower_opencnt > 0 || unsp->uns_upper_opencnt > 0) {
489 		/* vnode is already opend. */
490 		if (unsp->uns_upper_opencnt > 0)
491 			targetvp = uvp;
492 		else
493 			targetvp = lvp;
494 
495 		if (targetvp == lvp &&
496 		    (ap->a_mode & FWRITE) && lvp->v_type == VREG)
497 			targetvp = NULLVP;
498 	}
499 	if (targetvp == NULLVP) {
500 		if (uvp == NULLVP) {
501 			if ((ap->a_mode & FWRITE) && lvp->v_type == VREG) {
502 				error = unionfs_copyfile(unp,
503 				    !(ap->a_mode & O_TRUNC), cred, td);
504 				if (error != 0)
505 					goto unionfs_open_abort;
506 				targetvp = uvp = unp->un_uppervp;
507 			} else
508 				targetvp = lvp;
509 		} else
510 			targetvp = uvp;
511 	}
512 
513 	error = VOP_OPEN(targetvp, ap->a_mode, cred, td, ap->a_fp);
514 	if (error == 0) {
515 		if (targetvp == uvp) {
516 			if (uvp->v_type == VDIR && lvp != NULLVP &&
517 			    unsp->uns_lower_opencnt <= 0) {
518 				/* open lower for readdir */
519 				error = VOP_OPEN(lvp, FREAD, cred, td, NULL);
520 				if (error != 0) {
521 					VOP_CLOSE(uvp, ap->a_mode, cred, td);
522 					goto unionfs_open_abort;
523 				}
524 				unsp->uns_node_flag |= UNS_OPENL_4_READDIR;
525 				unsp->uns_lower_opencnt++;
526 			}
527 			unsp->uns_upper_opencnt++;
528 		} else {
529 			unsp->uns_lower_opencnt++;
530 			unsp->uns_lower_openmode = ap->a_mode;
531 		}
532 		ap->a_vp->v_object = targetvp->v_object;
533 	}
534 
535 unionfs_open_abort:
536 	if (error != 0)
537 		unionfs_tryrem_node_status(unp, unsp);
538 
539 	UNIONFS_INTERNAL_DEBUG("unionfs_open: leave (%d)\n", error);
540 
541 	return (error);
542 }
543 
544 static int
545 unionfs_close(struct vop_close_args *ap)
546 {
547 	int		error;
548 	int		locked;
549 	struct unionfs_node *unp;
550 	struct unionfs_node_status *unsp;
551 	struct ucred   *cred;
552 	struct thread  *td;
553 	struct vnode   *vp;
554 	struct vnode   *ovp;
555 
556 	UNIONFS_INTERNAL_DEBUG("unionfs_close: enter\n");
557 
558 	KASSERT_UNIONFS_VNODE(ap->a_vp);
559 
560 	locked = 0;
561 	vp = ap->a_vp;
562 	unp = VTOUNIONFS(vp);
563 	cred = ap->a_cred;
564 	td = ap->a_td;
565 
566 	if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
567 		if (vn_lock(vp, LK_UPGRADE) != 0)
568 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
569 		locked = 1;
570 	}
571 	unionfs_get_node_status(unp, td, &unsp);
572 
573 	if (unsp->uns_lower_opencnt <= 0 && unsp->uns_upper_opencnt <= 0) {
574 #ifdef DIAGNOSTIC
575 		printf("unionfs_close: warning: open count is 0\n");
576 #endif
577 		if (unp->un_uppervp != NULLVP)
578 			ovp = unp->un_uppervp;
579 		else
580 			ovp = unp->un_lowervp;
581 	} else if (unsp->uns_upper_opencnt > 0)
582 		ovp = unp->un_uppervp;
583 	else
584 		ovp = unp->un_lowervp;
585 
586 	error = VOP_CLOSE(ovp, ap->a_fflag, cred, td);
587 
588 	if (error != 0)
589 		goto unionfs_close_abort;
590 
591 	vp->v_object = ovp->v_object;
592 
593 	if (ovp == unp->un_uppervp) {
594 		unsp->uns_upper_opencnt--;
595 		if (unsp->uns_upper_opencnt == 0) {
596 			if (unsp->uns_node_flag & UNS_OPENL_4_READDIR) {
597 				VOP_CLOSE(unp->un_lowervp, FREAD, cred, td);
598 				unsp->uns_node_flag &= ~UNS_OPENL_4_READDIR;
599 				unsp->uns_lower_opencnt--;
600 			}
601 			if (unsp->uns_lower_opencnt > 0)
602 				vp->v_object = unp->un_lowervp->v_object;
603 		}
604 	} else
605 		unsp->uns_lower_opencnt--;
606 
607 unionfs_close_abort:
608 	unionfs_tryrem_node_status(unp, unsp);
609 
610 	if (locked != 0)
611 		vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
612 
613 	UNIONFS_INTERNAL_DEBUG("unionfs_close: leave (%d)\n", error);
614 
615 	return (error);
616 }
617 
618 /*
619  * Check the access mode toward shadow file/dir.
620  */
621 static int
622 unionfs_check_corrected_access(accmode_t accmode,
623 			     struct vattr *va,
624 			     struct ucred *cred)
625 {
626 	int		count;
627 	uid_t		uid;	/* upper side vnode's uid */
628 	gid_t		gid;	/* upper side vnode's gid */
629 	u_short		vmode;	/* upper side vnode's mode */
630 	u_short		mask;
631 
632 	mask = 0;
633 	uid = va->va_uid;
634 	gid = va->va_gid;
635 	vmode = va->va_mode;
636 
637 	/* check owner */
638 	if (cred->cr_uid == uid) {
639 		if (accmode & VEXEC)
640 			mask |= S_IXUSR;
641 		if (accmode & VREAD)
642 			mask |= S_IRUSR;
643 		if (accmode & VWRITE)
644 			mask |= S_IWUSR;
645 		return ((vmode & mask) == mask ? 0 : EACCES);
646 	}
647 
648 	/* check group */
649 	count = 0;
650 	if (groupmember(gid, cred)) {
651 		if (accmode & VEXEC)
652 			mask |= S_IXGRP;
653 		if (accmode & VREAD)
654 			mask |= S_IRGRP;
655 		if (accmode & VWRITE)
656 			mask |= S_IWGRP;
657 		return ((vmode & mask) == mask ? 0 : EACCES);
658 	}
659 
660 	/* check other */
661 	if (accmode & VEXEC)
662 		mask |= S_IXOTH;
663 	if (accmode & VREAD)
664 		mask |= S_IROTH;
665 	if (accmode & VWRITE)
666 		mask |= S_IWOTH;
667 
668 	return ((vmode & mask) == mask ? 0 : EACCES);
669 }
670 
671 static int
672 unionfs_access(struct vop_access_args *ap)
673 {
674 	struct unionfs_mount *ump;
675 	struct unionfs_node *unp;
676 	struct vnode   *uvp;
677 	struct vnode   *lvp;
678 	struct thread  *td;
679 	struct vattr	va;
680 	accmode_t	accmode;
681 	int		error;
682 
683 	UNIONFS_INTERNAL_DEBUG("unionfs_access: enter\n");
684 
685 	KASSERT_UNIONFS_VNODE(ap->a_vp);
686 
687 	ump = MOUNTTOUNIONFSMOUNT(ap->a_vp->v_mount);
688 	unp = VTOUNIONFS(ap->a_vp);
689 	uvp = unp->un_uppervp;
690 	lvp = unp->un_lowervp;
691 	td = ap->a_td;
692 	accmode = ap->a_accmode;
693 	error = EACCES;
694 
695 	if ((accmode & VWRITE) &&
696 	    (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)) {
697 		switch (ap->a_vp->v_type) {
698 		case VREG:
699 		case VDIR:
700 		case VLNK:
701 			return (EROFS);
702 		default:
703 			break;
704 		}
705 	}
706 
707 	if (uvp != NULLVP) {
708 		error = VOP_ACCESS(uvp, accmode, ap->a_cred, td);
709 
710 		UNIONFS_INTERNAL_DEBUG("unionfs_access: leave (%d)\n", error);
711 
712 		return (error);
713 	}
714 
715 	if (lvp != NULLVP) {
716 		if (accmode & VWRITE) {
717 			if (ump->um_uppervp->v_mount->mnt_flag & MNT_RDONLY) {
718 				switch (ap->a_vp->v_type) {
719 				case VREG:
720 				case VDIR:
721 				case VLNK:
722 					return (EROFS);
723 				default:
724 					break;
725 				}
726 			} else if (ap->a_vp->v_type == VREG || ap->a_vp->v_type == VDIR) {
727 				/* check shadow file/dir */
728 				if (ump->um_copymode != UNIONFS_TRANSPARENT) {
729 					error = unionfs_create_uppervattr(ump,
730 					    lvp, &va, ap->a_cred, td);
731 					if (error != 0)
732 						return (error);
733 
734 					error = unionfs_check_corrected_access(
735 					    accmode, &va, ap->a_cred);
736 					if (error != 0)
737 						return (error);
738 				}
739 			}
740 			accmode &= ~(VWRITE | VAPPEND);
741 			accmode |= VREAD; /* will copy to upper */
742 		}
743 		error = VOP_ACCESS(lvp, accmode, ap->a_cred, td);
744 	}
745 
746 	UNIONFS_INTERNAL_DEBUG("unionfs_access: leave (%d)\n", error);
747 
748 	return (error);
749 }
750 
751 static int
752 unionfs_getattr(struct vop_getattr_args *ap)
753 {
754 	int		error;
755 	struct unionfs_node *unp;
756 	struct unionfs_mount *ump;
757 	struct vnode   *uvp;
758 	struct vnode   *lvp;
759 	struct thread  *td;
760 	struct vattr	va;
761 
762 	UNIONFS_INTERNAL_DEBUG("unionfs_getattr: enter\n");
763 
764 	KASSERT_UNIONFS_VNODE(ap->a_vp);
765 
766 	unp = VTOUNIONFS(ap->a_vp);
767 	ump = MOUNTTOUNIONFSMOUNT(ap->a_vp->v_mount);
768 	uvp = unp->un_uppervp;
769 	lvp = unp->un_lowervp;
770 	td = curthread;
771 
772 	if (uvp != NULLVP) {
773 		if ((error = VOP_GETATTR(uvp, ap->a_vap, ap->a_cred)) == 0)
774 			ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
775 
776 		UNIONFS_INTERNAL_DEBUG("unionfs_getattr: leave mode=%o, uid=%d, gid=%d (%d)\n",
777 		    ap->a_vap->va_mode, ap->a_vap->va_uid,
778 		    ap->a_vap->va_gid, error);
779 
780 		return (error);
781 	}
782 
783 	error = VOP_GETATTR(lvp, ap->a_vap, ap->a_cred);
784 
785 	if (error == 0 && !(ump->um_uppervp->v_mount->mnt_flag & MNT_RDONLY)) {
786 		/* correct the attr toward shadow file/dir. */
787 		if (ap->a_vp->v_type == VREG || ap->a_vp->v_type == VDIR) {
788 			unionfs_create_uppervattr_core(ump, ap->a_vap, &va, td);
789 			ap->a_vap->va_mode = va.va_mode;
790 			ap->a_vap->va_uid = va.va_uid;
791 			ap->a_vap->va_gid = va.va_gid;
792 		}
793 	}
794 
795 	if (error == 0)
796 		ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsid.val[0];
797 
798 	UNIONFS_INTERNAL_DEBUG("unionfs_getattr: leave mode=%o, uid=%d, gid=%d (%d)\n",
799 	    ap->a_vap->va_mode, ap->a_vap->va_uid, ap->a_vap->va_gid, error);
800 
801 	return (error);
802 }
803 
804 static int
805 unionfs_setattr(struct vop_setattr_args *ap)
806 {
807 	int		error;
808 	struct unionfs_node *unp;
809 	struct vnode   *uvp;
810 	struct vnode   *lvp;
811 	struct thread  *td;
812 	struct vattr   *vap;
813 
814 	UNIONFS_INTERNAL_DEBUG("unionfs_setattr: enter\n");
815 
816 	KASSERT_UNIONFS_VNODE(ap->a_vp);
817 
818 	error = EROFS;
819 	unp = VTOUNIONFS(ap->a_vp);
820 	uvp = unp->un_uppervp;
821 	lvp = unp->un_lowervp;
822 	td = curthread;
823 	vap = ap->a_vap;
824 
825 	if ((ap->a_vp->v_mount->mnt_flag & MNT_RDONLY) &&
826 	    (vap->va_flags != VNOVAL || vap->va_uid != (uid_t)VNOVAL ||
827 	     vap->va_gid != (gid_t)VNOVAL || vap->va_atime.tv_sec != VNOVAL ||
828 	     vap->va_mtime.tv_sec != VNOVAL || vap->va_mode != (mode_t)VNOVAL))
829 		return (EROFS);
830 
831 	if (uvp == NULLVP && lvp->v_type == VREG) {
832 		error = unionfs_copyfile(unp, (vap->va_size != 0),
833 		    ap->a_cred, td);
834 		if (error != 0)
835 			return (error);
836 		uvp = unp->un_uppervp;
837 	}
838 
839 	if (uvp != NULLVP)
840 		error = VOP_SETATTR(uvp, vap, ap->a_cred);
841 
842 	UNIONFS_INTERNAL_DEBUG("unionfs_setattr: leave (%d)\n", error);
843 
844 	return (error);
845 }
846 
847 static int
848 unionfs_read(struct vop_read_args *ap)
849 {
850 	int		error;
851 	struct unionfs_node *unp;
852 	struct vnode   *tvp;
853 
854 	/* UNIONFS_INTERNAL_DEBUG("unionfs_read: enter\n"); */
855 
856 	KASSERT_UNIONFS_VNODE(ap->a_vp);
857 
858 	unp = VTOUNIONFS(ap->a_vp);
859 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
860 
861 	error = VOP_READ(tvp, ap->a_uio, ap->a_ioflag, ap->a_cred);
862 
863 	/* UNIONFS_INTERNAL_DEBUG("unionfs_read: leave (%d)\n", error); */
864 
865 	return (error);
866 }
867 
868 static int
869 unionfs_write(struct vop_write_args *ap)
870 {
871 	int		error;
872 	struct unionfs_node *unp;
873 	struct vnode   *tvp;
874 
875 	/* UNIONFS_INTERNAL_DEBUG("unionfs_write: enter\n"); */
876 
877 	KASSERT_UNIONFS_VNODE(ap->a_vp);
878 
879 	unp = VTOUNIONFS(ap->a_vp);
880 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
881 
882 	error = VOP_WRITE(tvp, ap->a_uio, ap->a_ioflag, ap->a_cred);
883 
884 	/* UNIONFS_INTERNAL_DEBUG("unionfs_write: leave (%d)\n", error); */
885 
886 	return (error);
887 }
888 
889 static int
890 unionfs_ioctl(struct vop_ioctl_args *ap)
891 {
892 	int error;
893 	struct unionfs_node *unp;
894 	struct unionfs_node_status *unsp;
895 	struct vnode   *ovp;
896 
897 	UNIONFS_INTERNAL_DEBUG("unionfs_ioctl: enter\n");
898 
899 	KASSERT_UNIONFS_VNODE(ap->a_vp);
900 
901  	vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
902 	unp = VTOUNIONFS(ap->a_vp);
903 	unionfs_get_node_status(unp, ap->a_td, &unsp);
904 	ovp = (unsp->uns_upper_opencnt ? unp->un_uppervp : unp->un_lowervp);
905 	unionfs_tryrem_node_status(unp, unsp);
906 	VOP_UNLOCK(ap->a_vp);
907 
908 	if (ovp == NULLVP)
909 		return (EBADF);
910 
911 	error = VOP_IOCTL(ovp, ap->a_command, ap->a_data, ap->a_fflag,
912 	    ap->a_cred, ap->a_td);
913 
914 	UNIONFS_INTERNAL_DEBUG("unionfs_ioctl: leave (%d)\n", error);
915 
916 	return (error);
917 }
918 
919 static int
920 unionfs_poll(struct vop_poll_args *ap)
921 {
922 	struct unionfs_node *unp;
923 	struct unionfs_node_status *unsp;
924 	struct vnode   *ovp;
925 
926 	KASSERT_UNIONFS_VNODE(ap->a_vp);
927 
928  	vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
929 	unp = VTOUNIONFS(ap->a_vp);
930 	unionfs_get_node_status(unp, ap->a_td, &unsp);
931 	ovp = (unsp->uns_upper_opencnt ? unp->un_uppervp : unp->un_lowervp);
932 	unionfs_tryrem_node_status(unp, unsp);
933 	VOP_UNLOCK(ap->a_vp);
934 
935 	if (ovp == NULLVP)
936 		return (EBADF);
937 
938 	return (VOP_POLL(ovp, ap->a_events, ap->a_cred, ap->a_td));
939 }
940 
941 static int
942 unionfs_fsync(struct vop_fsync_args *ap)
943 {
944 	struct unionfs_node *unp;
945 	struct unionfs_node_status *unsp;
946 	struct vnode   *ovp;
947 
948 	KASSERT_UNIONFS_VNODE(ap->a_vp);
949 
950 	unp = VTOUNIONFS(ap->a_vp);
951 	unionfs_get_node_status(unp, ap->a_td, &unsp);
952 	ovp = (unsp->uns_upper_opencnt ? unp->un_uppervp : unp->un_lowervp);
953 	unionfs_tryrem_node_status(unp, unsp);
954 
955 	if (ovp == NULLVP)
956 		return (EBADF);
957 
958 	return (VOP_FSYNC(ovp, ap->a_waitfor, ap->a_td));
959 }
960 
961 static int
962 unionfs_remove(struct vop_remove_args *ap)
963 {
964 	int		error;
965 	char	       *path;
966 	struct unionfs_node *dunp;
967 	struct unionfs_node *unp;
968 	struct unionfs_mount *ump;
969 	struct vnode   *udvp;
970 	struct vnode   *uvp;
971 	struct vnode   *lvp;
972 	struct vnode   *vp;
973 	struct componentname *cnp;
974 	struct componentname cn;
975 	struct thread  *td;
976 
977 	UNIONFS_INTERNAL_DEBUG("unionfs_remove: enter\n");
978 
979 	KASSERT_UNIONFS_VNODE(ap->a_dvp);
980 
981 	error = 0;
982 	dunp = VTOUNIONFS(ap->a_dvp);
983 	udvp = dunp->un_uppervp;
984 	cnp = ap->a_cnp;
985 	td = curthread;
986 
987 	if (ap->a_vp->v_op != &unionfs_vnodeops) {
988 		if (ap->a_vp->v_type != VSOCK)
989 			return (EINVAL);
990 		ump = NULL;
991 		vp = uvp = lvp = NULLVP;
992 		/* search vnode */
993 		VOP_UNLOCK(ap->a_vp);
994 		error = unionfs_relookup(udvp, &vp, cnp, &cn, td,
995 		    cnp->cn_nameptr, strlen(cnp->cn_nameptr), DELETE);
996 		if (error != 0 && error != ENOENT) {
997 			vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
998 			return (error);
999 		}
1000 
1001 		if (error == 0 && vp == ap->a_vp) {
1002 			/* target vnode in upper */
1003 			uvp = vp;
1004 			vrele(vp);
1005 			path = NULL;
1006 		} else {
1007 			/* target vnode in lower */
1008 			if (vp != NULLVP) {
1009 				if (udvp == vp)
1010 					vrele(vp);
1011 				else
1012 					vput(vp);
1013 			}
1014 			vn_lock(ap->a_vp, LK_EXCLUSIVE | LK_RETRY);
1015 			lvp = ap->a_vp;
1016 			path = ap->a_cnp->cn_nameptr;
1017 		}
1018 	} else {
1019 		ump = MOUNTTOUNIONFSMOUNT(ap->a_vp->v_mount);
1020 		unp = VTOUNIONFS(ap->a_vp);
1021 		uvp = unp->un_uppervp;
1022 		lvp = unp->un_lowervp;
1023 		path = unp->un_path;
1024 	}
1025 
1026 	if (udvp == NULLVP)
1027 		return (EROFS);
1028 
1029 	if (uvp != NULLVP) {
1030 		/*
1031 		 * XXX: if the vnode type is VSOCK, it will create whiteout
1032 		 *      after remove.
1033 		 */
1034 		if (ump == NULL || ump->um_whitemode == UNIONFS_WHITE_ALWAYS ||
1035 		    lvp != NULLVP)
1036 			cnp->cn_flags |= DOWHITEOUT;
1037 		error = VOP_REMOVE(udvp, uvp, cnp);
1038 	} else if (lvp != NULLVP)
1039 		error = unionfs_mkwhiteout(udvp, cnp, td, path);
1040 
1041 	UNIONFS_INTERNAL_DEBUG("unionfs_remove: leave (%d)\n", error);
1042 
1043 	return (error);
1044 }
1045 
1046 static int
1047 unionfs_link(struct vop_link_args *ap)
1048 {
1049 	int		error;
1050 	int		needrelookup;
1051 	struct unionfs_node *dunp;
1052 	struct unionfs_node *unp;
1053 	struct vnode   *udvp;
1054 	struct vnode   *uvp;
1055 	struct componentname *cnp;
1056 	struct thread  *td;
1057 
1058 	UNIONFS_INTERNAL_DEBUG("unionfs_link: enter\n");
1059 
1060 	KASSERT_UNIONFS_VNODE(ap->a_tdvp);
1061 	KASSERT_UNIONFS_VNODE(ap->a_vp);
1062 
1063 	error = 0;
1064 	needrelookup = 0;
1065 	dunp = VTOUNIONFS(ap->a_tdvp);
1066 	unp = NULL;
1067 	udvp = dunp->un_uppervp;
1068 	uvp = NULLVP;
1069 	cnp = ap->a_cnp;
1070 	td = curthread;
1071 
1072 	if (udvp == NULLVP)
1073 		return (EROFS);
1074 
1075 	if (ap->a_vp->v_op != &unionfs_vnodeops)
1076 		uvp = ap->a_vp;
1077 	else {
1078 		unp = VTOUNIONFS(ap->a_vp);
1079 
1080 		if (unp->un_uppervp == NULLVP) {
1081 			if (ap->a_vp->v_type != VREG)
1082 				return (EOPNOTSUPP);
1083 
1084 			error = unionfs_copyfile(unp, 1, cnp->cn_cred, td);
1085 			if (error != 0)
1086 				return (error);
1087 			needrelookup = 1;
1088 		}
1089 		uvp = unp->un_uppervp;
1090 	}
1091 
1092 	if (needrelookup != 0)
1093 		error = unionfs_relookup_for_create(ap->a_tdvp, cnp, td);
1094 
1095 	if (error == 0)
1096 		error = VOP_LINK(udvp, uvp, cnp);
1097 
1098 	UNIONFS_INTERNAL_DEBUG("unionfs_link: leave (%d)\n", error);
1099 
1100 	return (error);
1101 }
1102 
1103 static int
1104 unionfs_rename(struct vop_rename_args *ap)
1105 {
1106 	int		error;
1107 	struct vnode   *fdvp;
1108 	struct vnode   *fvp;
1109 	struct componentname *fcnp;
1110 	struct vnode   *tdvp;
1111 	struct vnode   *tvp;
1112 	struct componentname *tcnp;
1113 	struct vnode   *ltdvp;
1114 	struct vnode   *ltvp;
1115 	struct thread  *td;
1116 
1117 	/* rename target vnodes */
1118 	struct vnode   *rfdvp;
1119 	struct vnode   *rfvp;
1120 	struct vnode   *rtdvp;
1121 	struct vnode   *rtvp;
1122 
1123 	int		needrelookup;
1124 	struct unionfs_mount *ump;
1125 	struct unionfs_node *unp;
1126 
1127 	UNIONFS_INTERNAL_DEBUG("unionfs_rename: enter\n");
1128 
1129 	error = 0;
1130 	fdvp = ap->a_fdvp;
1131 	fvp = ap->a_fvp;
1132 	fcnp = ap->a_fcnp;
1133 	tdvp = ap->a_tdvp;
1134 	tvp = ap->a_tvp;
1135 	tcnp = ap->a_tcnp;
1136 	ltdvp = NULLVP;
1137 	ltvp = NULLVP;
1138 	td = curthread;
1139 	rfdvp = fdvp;
1140 	rfvp = fvp;
1141 	rtdvp = tdvp;
1142 	rtvp = tvp;
1143 	needrelookup = 0;
1144 
1145 #ifdef DIAGNOSTIC
1146 	if (!(fcnp->cn_flags & HASBUF) || !(tcnp->cn_flags & HASBUF))
1147 		panic("unionfs_rename: no name");
1148 #endif
1149 
1150 	/* check for cross device rename */
1151 	if (fvp->v_mount != tdvp->v_mount ||
1152 	    (tvp != NULLVP && fvp->v_mount != tvp->v_mount)) {
1153 		if (fvp->v_op != &unionfs_vnodeops)
1154 			error = ENODEV;
1155 		else
1156 			error = EXDEV;
1157 		goto unionfs_rename_abort;
1158 	}
1159 
1160 	/* Renaming a file to itself has no effect. */
1161 	if (fvp == tvp)
1162 		goto unionfs_rename_abort;
1163 
1164 	/*
1165 	 * from/to vnode is unionfs node.
1166 	 */
1167 
1168 	KASSERT_UNIONFS_VNODE(fdvp);
1169 	KASSERT_UNIONFS_VNODE(fvp);
1170 	KASSERT_UNIONFS_VNODE(tdvp);
1171 	if (tvp != NULLVP)
1172 		KASSERT_UNIONFS_VNODE(tvp);
1173 
1174 	unp = VTOUNIONFS(fdvp);
1175 #ifdef UNIONFS_IDBG_RENAME
1176 	UNIONFS_INTERNAL_DEBUG("fdvp=%p, ufdvp=%p, lfdvp=%p\n", fdvp, unp->un_uppervp, unp->un_lowervp);
1177 #endif
1178 	if (unp->un_uppervp == NULLVP) {
1179 		error = ENODEV;
1180 		goto unionfs_rename_abort;
1181 	}
1182 	rfdvp = unp->un_uppervp;
1183 	vref(rfdvp);
1184 
1185 	unp = VTOUNIONFS(fvp);
1186 #ifdef UNIONFS_IDBG_RENAME
1187 	UNIONFS_INTERNAL_DEBUG("fvp=%p, ufvp=%p, lfvp=%p\n", fvp, unp->un_uppervp, unp->un_lowervp);
1188 #endif
1189 	ump = MOUNTTOUNIONFSMOUNT(fvp->v_mount);
1190 	if (unp->un_uppervp == NULLVP) {
1191 		switch (fvp->v_type) {
1192 		case VREG:
1193 			if ((error = vn_lock(fvp, LK_EXCLUSIVE)) != 0)
1194 				goto unionfs_rename_abort;
1195 			error = unionfs_copyfile(unp, 1, fcnp->cn_cred, td);
1196 			VOP_UNLOCK(fvp);
1197 			if (error != 0)
1198 				goto unionfs_rename_abort;
1199 			break;
1200 		case VDIR:
1201 			if ((error = vn_lock(fvp, LK_EXCLUSIVE)) != 0)
1202 				goto unionfs_rename_abort;
1203 			error = unionfs_mkshadowdir(ump, rfdvp, unp, fcnp, td);
1204 			VOP_UNLOCK(fvp);
1205 			if (error != 0)
1206 				goto unionfs_rename_abort;
1207 			break;
1208 		default:
1209 			error = ENODEV;
1210 			goto unionfs_rename_abort;
1211 		}
1212 
1213 		needrelookup = 1;
1214 	}
1215 
1216 	if (unp->un_lowervp != NULLVP)
1217 		fcnp->cn_flags |= DOWHITEOUT;
1218 	rfvp = unp->un_uppervp;
1219 	vref(rfvp);
1220 
1221 	unp = VTOUNIONFS(tdvp);
1222 #ifdef UNIONFS_IDBG_RENAME
1223 	UNIONFS_INTERNAL_DEBUG("tdvp=%p, utdvp=%p, ltdvp=%p\n", tdvp, unp->un_uppervp, unp->un_lowervp);
1224 #endif
1225 	if (unp->un_uppervp == NULLVP) {
1226 		error = ENODEV;
1227 		goto unionfs_rename_abort;
1228 	}
1229 	rtdvp = unp->un_uppervp;
1230 	ltdvp = unp->un_lowervp;
1231 	vref(rtdvp);
1232 
1233 	if (tdvp == tvp) {
1234 		rtvp = rtdvp;
1235 		vref(rtvp);
1236 	} else if (tvp != NULLVP) {
1237 		unp = VTOUNIONFS(tvp);
1238 #ifdef UNIONFS_IDBG_RENAME
1239 		UNIONFS_INTERNAL_DEBUG("tvp=%p, utvp=%p, ltvp=%p\n", tvp, unp->un_uppervp, unp->un_lowervp);
1240 #endif
1241 		if (unp->un_uppervp == NULLVP)
1242 			rtvp = NULLVP;
1243 		else {
1244 			if (tvp->v_type == VDIR) {
1245 				error = EINVAL;
1246 				goto unionfs_rename_abort;
1247 			}
1248 			rtvp = unp->un_uppervp;
1249 			ltvp = unp->un_lowervp;
1250 			vref(rtvp);
1251 		}
1252 	}
1253 
1254 	if (rfvp == rtvp)
1255 		goto unionfs_rename_abort;
1256 
1257 	if (needrelookup != 0) {
1258 		if ((error = vn_lock(fdvp, LK_EXCLUSIVE)) != 0)
1259 			goto unionfs_rename_abort;
1260 		error = unionfs_relookup_for_delete(fdvp, fcnp, td);
1261 		VOP_UNLOCK(fdvp);
1262 		if (error != 0)
1263 			goto unionfs_rename_abort;
1264 
1265 		/* Locke of tvp is canceled in order to avoid recursive lock. */
1266 		if (tvp != NULLVP && tvp != tdvp)
1267 			VOP_UNLOCK(tvp);
1268 		error = unionfs_relookup_for_rename(tdvp, tcnp, td);
1269 		if (tvp != NULLVP && tvp != tdvp)
1270 			vn_lock(tvp, LK_EXCLUSIVE | LK_RETRY);
1271 		if (error != 0)
1272 			goto unionfs_rename_abort;
1273 	}
1274 
1275 	error = VOP_RENAME(rfdvp, rfvp, fcnp, rtdvp, rtvp, tcnp);
1276 
1277 	if (error == 0) {
1278 		if (rtvp != NULLVP && rtvp->v_type == VDIR)
1279 			cache_purge(tdvp);
1280 		if (fvp->v_type == VDIR && fdvp != tdvp)
1281 			cache_purge(fdvp);
1282 	}
1283 
1284 	if (ltdvp != NULLVP)
1285 		VOP_UNLOCK(ltdvp);
1286 	if (tdvp != rtdvp)
1287 		vrele(tdvp);
1288 	if (ltvp != NULLVP)
1289 		VOP_UNLOCK(ltvp);
1290 	if (tvp != rtvp && tvp != NULLVP) {
1291 		if (rtvp == NULLVP)
1292 			vput(tvp);
1293 		else
1294 			vrele(tvp);
1295 	}
1296 	if (fdvp != rfdvp)
1297 		vrele(fdvp);
1298 	if (fvp != rfvp)
1299 		vrele(fvp);
1300 
1301 	UNIONFS_INTERNAL_DEBUG("unionfs_rename: leave (%d)\n", error);
1302 
1303 	return (error);
1304 
1305 unionfs_rename_abort:
1306 	vput(tdvp);
1307 	if (tdvp != rtdvp)
1308 		vrele(rtdvp);
1309 	if (tvp != NULLVP) {
1310 		if (tdvp != tvp)
1311 			vput(tvp);
1312 		else
1313 			vrele(tvp);
1314 	}
1315 	if (tvp != rtvp && rtvp != NULLVP)
1316 		vrele(rtvp);
1317 	if (fdvp != rfdvp)
1318 		vrele(rfdvp);
1319 	if (fvp != rfvp)
1320 		vrele(rfvp);
1321 	vrele(fdvp);
1322 	vrele(fvp);
1323 
1324 	UNIONFS_INTERNAL_DEBUG("unionfs_rename: leave (%d)\n", error);
1325 
1326 	return (error);
1327 }
1328 
1329 static int
1330 unionfs_mkdir(struct vop_mkdir_args *ap)
1331 {
1332 	int		error;
1333 	int		lkflags;
1334 	struct unionfs_node *dunp;
1335 	struct componentname *cnp;
1336 	struct thread  *td;
1337 	struct vnode   *udvp;
1338 	struct vnode   *uvp;
1339 	struct vattr	va;
1340 
1341 	UNIONFS_INTERNAL_DEBUG("unionfs_mkdir: enter\n");
1342 
1343 	KASSERT_UNIONFS_VNODE(ap->a_dvp);
1344 
1345 	error = EROFS;
1346 	dunp = VTOUNIONFS(ap->a_dvp);
1347 	cnp = ap->a_cnp;
1348 	lkflags = cnp->cn_lkflags;
1349 	td = curthread;
1350 	udvp = dunp->un_uppervp;
1351 
1352 	if (udvp != NULLVP) {
1353 		/* check opaque */
1354 		if (!(cnp->cn_flags & ISWHITEOUT)) {
1355 			error = VOP_GETATTR(udvp, &va, cnp->cn_cred);
1356 			if (error != 0)
1357 				return (error);
1358 			if (va.va_flags & OPAQUE)
1359 				cnp->cn_flags |= ISWHITEOUT;
1360 		}
1361 
1362 		if ((error = VOP_MKDIR(udvp, &uvp, cnp, ap->a_vap)) == 0) {
1363 			VOP_UNLOCK(uvp);
1364 			cnp->cn_lkflags = LK_EXCLUSIVE;
1365 			error = unionfs_nodeget(ap->a_dvp->v_mount, uvp, NULLVP,
1366 			    ap->a_dvp, ap->a_vpp, cnp, td);
1367 			cnp->cn_lkflags = lkflags;
1368 			vrele(uvp);
1369 		}
1370 	}
1371 
1372 	UNIONFS_INTERNAL_DEBUG("unionfs_mkdir: leave (%d)\n", error);
1373 
1374 	return (error);
1375 }
1376 
1377 static int
1378 unionfs_rmdir(struct vop_rmdir_args *ap)
1379 {
1380 	int		error;
1381 	struct unionfs_node *dunp;
1382 	struct unionfs_node *unp;
1383 	struct unionfs_mount *ump;
1384 	struct componentname *cnp;
1385 	struct thread  *td;
1386 	struct vnode   *udvp;
1387 	struct vnode   *uvp;
1388 	struct vnode   *lvp;
1389 
1390 	UNIONFS_INTERNAL_DEBUG("unionfs_rmdir: enter\n");
1391 
1392 	KASSERT_UNIONFS_VNODE(ap->a_dvp);
1393 	KASSERT_UNIONFS_VNODE(ap->a_vp);
1394 
1395 	error = 0;
1396 	dunp = VTOUNIONFS(ap->a_dvp);
1397 	unp = VTOUNIONFS(ap->a_vp);
1398 	cnp = ap->a_cnp;
1399 	td = curthread;
1400 	udvp = dunp->un_uppervp;
1401 	uvp = unp->un_uppervp;
1402 	lvp = unp->un_lowervp;
1403 
1404 	if (udvp == NULLVP)
1405 		return (EROFS);
1406 
1407 	if (udvp == uvp)
1408 		return (EOPNOTSUPP);
1409 
1410 	if (uvp != NULLVP) {
1411 		if (lvp != NULLVP) {
1412 			error = unionfs_check_rmdir(ap->a_vp, cnp->cn_cred, td);
1413 			if (error != 0)
1414 				return (error);
1415 		}
1416 		ump = MOUNTTOUNIONFSMOUNT(ap->a_vp->v_mount);
1417 		if (ump->um_whitemode == UNIONFS_WHITE_ALWAYS || lvp != NULLVP)
1418 			cnp->cn_flags |= DOWHITEOUT;
1419 		error = unionfs_relookup_for_delete(ap->a_dvp, cnp, td);
1420 		if (!error)
1421 			error = VOP_RMDIR(udvp, uvp, cnp);
1422 	}
1423 	else if (lvp != NULLVP)
1424 		error = unionfs_mkwhiteout(udvp, cnp, td, unp->un_path);
1425 
1426 	if (error == 0) {
1427 		cache_purge(ap->a_dvp);
1428 		cache_purge(ap->a_vp);
1429 	}
1430 
1431 	UNIONFS_INTERNAL_DEBUG("unionfs_rmdir: leave (%d)\n", error);
1432 
1433 	return (error);
1434 }
1435 
1436 static int
1437 unionfs_symlink(struct vop_symlink_args *ap)
1438 {
1439 	int		error;
1440 	int		lkflags;
1441 	struct unionfs_node *dunp;
1442 	struct componentname *cnp;
1443 	struct thread  *td;
1444 	struct vnode   *udvp;
1445 	struct vnode   *uvp;
1446 
1447 	UNIONFS_INTERNAL_DEBUG("unionfs_symlink: enter\n");
1448 
1449 	KASSERT_UNIONFS_VNODE(ap->a_dvp);
1450 
1451 	error = EROFS;
1452 	dunp = VTOUNIONFS(ap->a_dvp);
1453 	cnp = ap->a_cnp;
1454 	lkflags = cnp->cn_lkflags;
1455 	td = curthread;
1456 	udvp = dunp->un_uppervp;
1457 
1458 	if (udvp != NULLVP) {
1459 		error = VOP_SYMLINK(udvp, &uvp, cnp, ap->a_vap, ap->a_target);
1460 		if (error == 0) {
1461 			VOP_UNLOCK(uvp);
1462 			cnp->cn_lkflags = LK_EXCLUSIVE;
1463 			error = unionfs_nodeget(ap->a_dvp->v_mount, uvp, NULLVP,
1464 			    ap->a_dvp, ap->a_vpp, cnp, td);
1465 			cnp->cn_lkflags = lkflags;
1466 			vrele(uvp);
1467 		}
1468 	}
1469 
1470 	UNIONFS_INTERNAL_DEBUG("unionfs_symlink: leave (%d)\n", error);
1471 
1472 	return (error);
1473 }
1474 
1475 static int
1476 unionfs_readdir(struct vop_readdir_args *ap)
1477 {
1478 	int		error;
1479 	int		eofflag;
1480 	int		locked;
1481 	int		uio_offset_bk;
1482 	struct unionfs_node *unp;
1483 	struct unionfs_node_status *unsp;
1484 	struct uio     *uio;
1485 	struct vnode   *vp;
1486 	struct vnode   *uvp;
1487 	struct vnode   *lvp;
1488 	struct thread  *td;
1489 	struct vattr    va;
1490 
1491 	int		ncookies_bk;
1492 	u_long         *cookies_bk;
1493 
1494 	UNIONFS_INTERNAL_DEBUG("unionfs_readdir: enter\n");
1495 
1496 	KASSERT_UNIONFS_VNODE(ap->a_vp);
1497 
1498 	error = 0;
1499 	eofflag = 0;
1500 	locked = 0;
1501 	uio_offset_bk = 0;
1502 	uio = ap->a_uio;
1503 	uvp = NULLVP;
1504 	lvp = NULLVP;
1505 	td = uio->uio_td;
1506 	ncookies_bk = 0;
1507 	cookies_bk = NULL;
1508 
1509 	vp = ap->a_vp;
1510 	if (vp->v_type != VDIR)
1511 		return (ENOTDIR);
1512 
1513 	/* check the open count. unionfs needs to open before readdir. */
1514 	if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
1515 		if (vn_lock(vp, LK_UPGRADE) != 0)
1516 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1517 		locked = 1;
1518 	}
1519 	unp = VTOUNIONFS(vp);
1520 	if (unp == NULL)
1521 		error = EBADF;
1522 	else {
1523 		uvp = unp->un_uppervp;
1524 		lvp = unp->un_lowervp;
1525 		unionfs_get_node_status(unp, td, &unsp);
1526 		if ((uvp != NULLVP && unsp->uns_upper_opencnt <= 0) ||
1527 			(lvp != NULLVP && unsp->uns_lower_opencnt <= 0)) {
1528 			unionfs_tryrem_node_status(unp, unsp);
1529 			error = EBADF;
1530 		}
1531 	}
1532 	if (locked)
1533 		vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
1534 	if (error != 0)
1535 		goto unionfs_readdir_exit;
1536 
1537 	/* check opaque */
1538 	if (uvp != NULLVP && lvp != NULLVP) {
1539 		if ((error = VOP_GETATTR(uvp, &va, ap->a_cred)) != 0)
1540 			goto unionfs_readdir_exit;
1541 		if (va.va_flags & OPAQUE)
1542 			lvp = NULLVP;
1543 	}
1544 
1545 	/* upper only */
1546 	if (uvp != NULLVP && lvp == NULLVP) {
1547 		error = VOP_READDIR(uvp, uio, ap->a_cred, ap->a_eofflag,
1548 		    ap->a_ncookies, ap->a_cookies);
1549 		unsp->uns_readdir_status = 0;
1550 
1551 		goto unionfs_readdir_exit;
1552 	}
1553 
1554 	/* lower only */
1555 	if (uvp == NULLVP && lvp != NULLVP) {
1556 		error = VOP_READDIR(lvp, uio, ap->a_cred, ap->a_eofflag,
1557 		    ap->a_ncookies, ap->a_cookies);
1558 		unsp->uns_readdir_status = 2;
1559 
1560 		goto unionfs_readdir_exit;
1561 	}
1562 
1563 	/*
1564 	 * readdir upper and lower
1565 	 */
1566 	KASSERT(uvp != NULLVP, ("unionfs_readdir: null upper vp"));
1567 	KASSERT(lvp != NULLVP, ("unionfs_readdir: null lower vp"));
1568 	if (uio->uio_offset == 0)
1569 		unsp->uns_readdir_status = 0;
1570 
1571 	if (unsp->uns_readdir_status == 0) {
1572 		/* read upper */
1573 		error = VOP_READDIR(uvp, uio, ap->a_cred, &eofflag,
1574 				    ap->a_ncookies, ap->a_cookies);
1575 
1576 		if (error != 0 || eofflag == 0)
1577 			goto unionfs_readdir_exit;
1578 		unsp->uns_readdir_status = 1;
1579 
1580 		/*
1581 		 * UFS(and other FS) needs size of uio_resid larger than
1582 		 * DIRBLKSIZ.
1583 		 * size of DIRBLKSIZ equals DEV_BSIZE.
1584 		 * (see: ufs/ufs/ufs_vnops.c ufs_readdir func , ufs/ufs/dir.h)
1585 		 */
1586 		if (uio->uio_resid <= (uio->uio_resid & (DEV_BSIZE -1)))
1587 			goto unionfs_readdir_exit;
1588 
1589 		/*
1590 		 * Backup cookies.
1591 		 * It prepares to readdir in lower.
1592 		 */
1593 		if (ap->a_ncookies != NULL) {
1594 			ncookies_bk = *(ap->a_ncookies);
1595 			*(ap->a_ncookies) = 0;
1596 		}
1597 		if (ap->a_cookies != NULL) {
1598 			cookies_bk = *(ap->a_cookies);
1599 			*(ap->a_cookies) = NULL;
1600 		}
1601 	}
1602 
1603 	/* initialize for readdir in lower */
1604 	if (unsp->uns_readdir_status == 1) {
1605 		unsp->uns_readdir_status = 2;
1606 		/*
1607 		 * Backup uio_offset. See the comment after the
1608 		 * VOP_READDIR call on the lower layer.
1609 		 */
1610 		uio_offset_bk = uio->uio_offset;
1611 		uio->uio_offset = 0;
1612 	}
1613 
1614 	if (lvp == NULLVP) {
1615 		error = EBADF;
1616 		goto unionfs_readdir_exit;
1617 	}
1618 	/* read lower */
1619 	error = VOP_READDIR(lvp, uio, ap->a_cred, ap->a_eofflag,
1620 			    ap->a_ncookies, ap->a_cookies);
1621 
1622 	/*
1623 	 * We can't return an uio_offset of 0: this would trigger an
1624 	 * infinite loop, because the next call to unionfs_readdir would
1625 	 * always restart with the upper layer (uio_offset == 0) and
1626 	 * always return some data.
1627 	 *
1628 	 * This happens when the lower layer root directory is removed.
1629 	 * (A root directory deleting of unionfs should not be permitted.
1630 	 *  But current VFS can not do it.)
1631 	 */
1632 	if (uio->uio_offset == 0)
1633 		uio->uio_offset = uio_offset_bk;
1634 
1635 	if (cookies_bk != NULL) {
1636 		/* merge cookies */
1637 		int		size;
1638 		u_long         *newcookies, *pos;
1639 
1640 		size = *(ap->a_ncookies) + ncookies_bk;
1641 		newcookies = (u_long *) malloc(size * sizeof(u_long),
1642 		    M_TEMP, M_WAITOK);
1643 		pos = newcookies;
1644 
1645 		memcpy(pos, cookies_bk, ncookies_bk * sizeof(u_long));
1646 		pos += ncookies_bk;
1647 		memcpy(pos, *(ap->a_cookies), *(ap->a_ncookies) * sizeof(u_long));
1648 		free(cookies_bk, M_TEMP);
1649 		free(*(ap->a_cookies), M_TEMP);
1650 		*(ap->a_ncookies) = size;
1651 		*(ap->a_cookies) = newcookies;
1652 	}
1653 
1654 unionfs_readdir_exit:
1655 	if (error != 0 && ap->a_eofflag != NULL)
1656 		*(ap->a_eofflag) = 1;
1657 
1658 	UNIONFS_INTERNAL_DEBUG("unionfs_readdir: leave (%d)\n", error);
1659 
1660 	return (error);
1661 }
1662 
1663 static int
1664 unionfs_readlink(struct vop_readlink_args *ap)
1665 {
1666 	int error;
1667 	struct unionfs_node *unp;
1668 	struct vnode   *vp;
1669 
1670 	UNIONFS_INTERNAL_DEBUG("unionfs_readlink: enter\n");
1671 
1672 	KASSERT_UNIONFS_VNODE(ap->a_vp);
1673 
1674 	unp = VTOUNIONFS(ap->a_vp);
1675 	vp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
1676 
1677 	error = VOP_READLINK(vp, ap->a_uio, ap->a_cred);
1678 
1679 	UNIONFS_INTERNAL_DEBUG("unionfs_readlink: leave (%d)\n", error);
1680 
1681 	return (error);
1682 }
1683 
1684 static int
1685 unionfs_getwritemount(struct vop_getwritemount_args *ap)
1686 {
1687 	int		error;
1688 	struct vnode   *uvp;
1689 	struct vnode   *vp;
1690 
1691 	UNIONFS_INTERNAL_DEBUG("unionfs_getwritemount: enter\n");
1692 
1693 	error = 0;
1694 	vp = ap->a_vp;
1695 
1696 	if (vp == NULLVP || (vp->v_mount->mnt_flag & MNT_RDONLY))
1697 		return (EACCES);
1698 
1699 	KASSERT_UNIONFS_VNODE(vp);
1700 
1701 	uvp = UNIONFSVPTOUPPERVP(vp);
1702 	if (uvp == NULLVP && VREG == vp->v_type)
1703 		uvp = UNIONFSVPTOUPPERVP(VTOUNIONFS(vp)->un_dvp);
1704 
1705 	if (uvp != NULLVP)
1706 		error = VOP_GETWRITEMOUNT(uvp, ap->a_mpp);
1707 	else {
1708 		VI_LOCK(vp);
1709 		if (vp->v_holdcnt == 0)
1710 			error = EOPNOTSUPP;
1711 		else
1712 			error = EACCES;
1713 		VI_UNLOCK(vp);
1714 	}
1715 
1716 	UNIONFS_INTERNAL_DEBUG("unionfs_getwritemount: leave (%d)\n", error);
1717 
1718 	return (error);
1719 }
1720 
1721 static int
1722 unionfs_inactive(struct vop_inactive_args *ap)
1723 {
1724 	ap->a_vp->v_object = NULL;
1725 	vrecycle(ap->a_vp);
1726 	return (0);
1727 }
1728 
1729 static int
1730 unionfs_reclaim(struct vop_reclaim_args *ap)
1731 {
1732 	/* UNIONFS_INTERNAL_DEBUG("unionfs_reclaim: enter\n"); */
1733 
1734 	unionfs_noderem(ap->a_vp, ap->a_td);
1735 
1736 	/* UNIONFS_INTERNAL_DEBUG("unionfs_reclaim: leave\n"); */
1737 
1738 	return (0);
1739 }
1740 
1741 static int
1742 unionfs_print(struct vop_print_args *ap)
1743 {
1744 	struct unionfs_node *unp;
1745 	/* struct unionfs_node_status *unsp; */
1746 
1747 	unp = VTOUNIONFS(ap->a_vp);
1748 	/* unionfs_get_node_status(unp, curthread, &unsp); */
1749 
1750 	printf("unionfs_vp=%p, uppervp=%p, lowervp=%p\n",
1751 	    ap->a_vp, unp->un_uppervp, unp->un_lowervp);
1752 	/*
1753 	printf("unionfs opencnt: uppervp=%d, lowervp=%d\n",
1754 	    unsp->uns_upper_opencnt, unsp->uns_lower_opencnt);
1755 	*/
1756 
1757 	if (unp->un_uppervp != NULLVP)
1758 		vn_printf(unp->un_uppervp, "unionfs: upper ");
1759 	if (unp->un_lowervp != NULLVP)
1760 		vn_printf(unp->un_lowervp, "unionfs: lower ");
1761 
1762 	return (0);
1763 }
1764 
1765 static int
1766 unionfs_islocked(struct vop_islocked_args *ap)
1767 {
1768 	struct unionfs_node *unp;
1769 
1770 	KASSERT_UNIONFS_VNODE(ap->a_vp);
1771 
1772 	unp = VTOUNIONFS(ap->a_vp);
1773 	if (unp == NULL)
1774 		return (vop_stdislocked(ap));
1775 
1776 	if (unp->un_uppervp != NULLVP)
1777 		return (VOP_ISLOCKED(unp->un_uppervp));
1778 	if (unp->un_lowervp != NULLVP)
1779 		return (VOP_ISLOCKED(unp->un_lowervp));
1780 	return (vop_stdislocked(ap));
1781 }
1782 
1783 static int
1784 unionfs_get_llt_revlock(struct vnode *vp, int flags)
1785 {
1786 	int revlock;
1787 
1788 	revlock = 0;
1789 
1790 	switch (flags & LK_TYPE_MASK) {
1791 	case LK_SHARED:
1792 		if (VOP_ISLOCKED(vp) == LK_EXCLUSIVE)
1793 			revlock = LK_UPGRADE;
1794 		else
1795 			revlock = LK_RELEASE;
1796 		break;
1797 	case LK_EXCLUSIVE:
1798 	case LK_UPGRADE:
1799 		revlock = LK_RELEASE;
1800 		break;
1801 	case LK_DOWNGRADE:
1802 		revlock = LK_UPGRADE;
1803 		break;
1804 	default:
1805 		break;
1806 	}
1807 
1808 	return (revlock);
1809 }
1810 
1811 /*
1812  * The state of an acquired lock is adjusted similarly to
1813  * the time of error generating.
1814  * flags: LK_RELEASE or LK_UPGRADE
1815  */
1816 static void
1817 unionfs_revlock(struct vnode *vp, int flags)
1818 {
1819 	if (flags & LK_RELEASE)
1820 		VOP_UNLOCK_FLAGS(vp, flags);
1821 	else {
1822 		/* UPGRADE */
1823 		if (vn_lock(vp, flags) != 0)
1824 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1825 	}
1826 }
1827 
1828 static int
1829 unionfs_lock(struct vop_lock1_args *ap)
1830 {
1831 	int		error;
1832 	int		flags;
1833 	int		revlock;
1834 	int		interlock;
1835 	int		uhold;
1836 	struct mount   *mp;
1837 	struct unionfs_mount *ump;
1838 	struct unionfs_node *unp;
1839 	struct vnode   *vp;
1840 	struct vnode   *uvp;
1841 	struct vnode   *lvp;
1842 
1843 	KASSERT_UNIONFS_VNODE(ap->a_vp);
1844 
1845 	error = 0;
1846 	interlock = 1;
1847 	uhold = 0;
1848 	flags = ap->a_flags;
1849 	vp = ap->a_vp;
1850 
1851 	if (LK_RELEASE == (flags & LK_TYPE_MASK) || !(flags & LK_TYPE_MASK))
1852 		return (VOP_UNLOCK_FLAGS(vp, flags | LK_RELEASE));
1853 
1854 	if ((flags & LK_INTERLOCK) == 0)
1855 		VI_LOCK(vp);
1856 
1857 	mp = vp->v_mount;
1858 	if (mp == NULL)
1859 		goto unionfs_lock_null_vnode;
1860 
1861 	ump = MOUNTTOUNIONFSMOUNT(mp);
1862 	unp = VTOUNIONFS(vp);
1863 	if (ump == NULL || unp == NULL)
1864 		goto unionfs_lock_null_vnode;
1865 	lvp = unp->un_lowervp;
1866 	uvp = unp->un_uppervp;
1867 
1868 	if ((revlock = unionfs_get_llt_revlock(vp, flags)) == 0)
1869 		panic("unknown lock type: 0x%x", flags & LK_TYPE_MASK);
1870 
1871 	if ((vp->v_iflag & VI_OWEINACT) != 0)
1872 		flags |= LK_NOWAIT;
1873 
1874 	/*
1875 	 * Sometimes, lower or upper is already exclusive locked.
1876 	 * (ex. vfs_domount: mounted vnode is already locked.)
1877 	 */
1878 	if ((flags & LK_TYPE_MASK) == LK_EXCLUSIVE &&
1879 	    vp == ump->um_rootvp)
1880 		flags |= LK_CANRECURSE;
1881 
1882 	if (lvp != NULLVP) {
1883 		if (uvp != NULLVP && flags & LK_UPGRADE) {
1884 			/* Share Lock is once released and a deadlock is avoided.  */
1885 			vholdnz(uvp);
1886 			uhold = 1;
1887 			VOP_UNLOCK(uvp);
1888 			unp = VTOUNIONFS(vp);
1889 			if (unp == NULL) {
1890 				/* vnode is released. */
1891 				VI_UNLOCK(vp);
1892 				VOP_UNLOCK(lvp);
1893 				vdrop(uvp);
1894 				return (EBUSY);
1895 			}
1896 		}
1897 		VI_LOCK_FLAGS(lvp, MTX_DUPOK);
1898 		flags |= LK_INTERLOCK;
1899 		vholdl(lvp);
1900 
1901 		VI_UNLOCK(vp);
1902 		ap->a_flags &= ~LK_INTERLOCK;
1903 
1904 		error = VOP_LOCK(lvp, flags);
1905 
1906 		VI_LOCK(vp);
1907 		unp = VTOUNIONFS(vp);
1908 		if (unp == NULL) {
1909 			/* vnode is released. */
1910 			VI_UNLOCK(vp);
1911 			if (error == 0)
1912 				VOP_UNLOCK(lvp);
1913 			vdrop(lvp);
1914 			if (uhold != 0)
1915 				vdrop(uvp);
1916 			return (vop_stdlock(ap));
1917 		}
1918 	}
1919 
1920 	if (error == 0 && uvp != NULLVP) {
1921 		if (uhold && flags & LK_UPGRADE) {
1922 			flags &= ~LK_TYPE_MASK;
1923 			flags |= LK_EXCLUSIVE;
1924 		}
1925 		VI_LOCK_FLAGS(uvp, MTX_DUPOK);
1926 		flags |= LK_INTERLOCK;
1927 		if (uhold == 0) {
1928 			vholdl(uvp);
1929 			uhold = 1;
1930 		}
1931 
1932 		VI_UNLOCK(vp);
1933 		ap->a_flags &= ~LK_INTERLOCK;
1934 
1935 		error = VOP_LOCK(uvp, flags);
1936 
1937 		VI_LOCK(vp);
1938 		unp = VTOUNIONFS(vp);
1939 		if (unp == NULL) {
1940 			/* vnode is released. */
1941 			VI_UNLOCK(vp);
1942 			if (error == 0)
1943 				VOP_UNLOCK(uvp);
1944 			vdrop(uvp);
1945 			if (lvp != NULLVP) {
1946 				VOP_UNLOCK(lvp);
1947 				vdrop(lvp);
1948 			}
1949 			return (vop_stdlock(ap));
1950 		}
1951 		if (error != 0 && lvp != NULLVP) {
1952 			/* rollback */
1953 			VI_UNLOCK(vp);
1954 			unionfs_revlock(lvp, revlock);
1955 			interlock = 0;
1956 		}
1957 	}
1958 
1959 	if (interlock)
1960 		VI_UNLOCK(vp);
1961 	if (lvp != NULLVP)
1962 		vdrop(lvp);
1963 	if (uhold != 0)
1964 		vdrop(uvp);
1965 
1966 	return (error);
1967 
1968 unionfs_lock_null_vnode:
1969 	ap->a_flags |= LK_INTERLOCK;
1970 	return (vop_stdlock(ap));
1971 }
1972 
1973 static int
1974 unionfs_unlock(struct vop_unlock_args *ap)
1975 {
1976 	int		error;
1977 	int		uhold;
1978 	struct vnode   *vp;
1979 	struct vnode   *lvp;
1980 	struct vnode   *uvp;
1981 	struct unionfs_node *unp;
1982 
1983 	KASSERT_UNIONFS_VNODE(ap->a_vp);
1984 
1985 	error = 0;
1986 	uhold = 0;
1987 	vp = ap->a_vp;
1988 
1989 	unp = VTOUNIONFS(vp);
1990 	if (unp == NULL)
1991 		goto unionfs_unlock_null_vnode;
1992 	lvp = unp->un_lowervp;
1993 	uvp = unp->un_uppervp;
1994 
1995 	if (lvp != NULLVP) {
1996 		vholdnz(lvp);
1997 		error = VOP_UNLOCK(lvp);
1998 	}
1999 
2000 	if (error == 0 && uvp != NULLVP) {
2001 		vholdnz(uvp);
2002 		uhold = 1;
2003 		error = VOP_UNLOCK(uvp);
2004 	}
2005 
2006 	if (lvp != NULLVP)
2007 		vdrop(lvp);
2008 	if (uhold != 0)
2009 		vdrop(uvp);
2010 
2011 	return error;
2012 
2013 unionfs_unlock_null_vnode:
2014 	return (vop_stdunlock(ap));
2015 }
2016 
2017 static int
2018 unionfs_pathconf(struct vop_pathconf_args *ap)
2019 {
2020 	struct unionfs_node *unp;
2021 	struct vnode   *vp;
2022 
2023 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2024 
2025 	unp = VTOUNIONFS(ap->a_vp);
2026 	vp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
2027 
2028 	return (VOP_PATHCONF(vp, ap->a_name, ap->a_retval));
2029 }
2030 
2031 static int
2032 unionfs_advlock(struct vop_advlock_args *ap)
2033 {
2034 	int error;
2035 	struct unionfs_node *unp;
2036 	struct unionfs_node_status *unsp;
2037 	struct vnode   *vp;
2038 	struct vnode   *uvp;
2039 	struct thread  *td;
2040 
2041 	UNIONFS_INTERNAL_DEBUG("unionfs_advlock: enter\n");
2042 
2043 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2044 
2045 	vp = ap->a_vp;
2046 	td = curthread;
2047 
2048 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2049 
2050 	unp = VTOUNIONFS(ap->a_vp);
2051 	uvp = unp->un_uppervp;
2052 
2053 	if (uvp == NULLVP) {
2054 		error = unionfs_copyfile(unp, 1, td->td_ucred, td);
2055 		if (error != 0)
2056 			goto unionfs_advlock_abort;
2057 		uvp = unp->un_uppervp;
2058 
2059 		unionfs_get_node_status(unp, td, &unsp);
2060 		if (unsp->uns_lower_opencnt > 0) {
2061 			/* try reopen the vnode */
2062 			error = VOP_OPEN(uvp, unsp->uns_lower_openmode,
2063 				td->td_ucred, td, NULL);
2064 			if (error)
2065 				goto unionfs_advlock_abort;
2066 			unsp->uns_upper_opencnt++;
2067 			VOP_CLOSE(unp->un_lowervp, unsp->uns_lower_openmode, td->td_ucred, td);
2068 			unsp->uns_lower_opencnt--;
2069 		} else
2070 			unionfs_tryrem_node_status(unp, unsp);
2071 	}
2072 
2073 	VOP_UNLOCK(vp);
2074 
2075 	error = VOP_ADVLOCK(uvp, ap->a_id, ap->a_op, ap->a_fl, ap->a_flags);
2076 
2077 	UNIONFS_INTERNAL_DEBUG("unionfs_advlock: leave (%d)\n", error);
2078 
2079 	return error;
2080 
2081 unionfs_advlock_abort:
2082 	VOP_UNLOCK(vp);
2083 
2084 	UNIONFS_INTERNAL_DEBUG("unionfs_advlock: leave (%d)\n", error);
2085 
2086 	return error;
2087 }
2088 
2089 static int
2090 unionfs_strategy(struct vop_strategy_args *ap)
2091 {
2092 	struct unionfs_node *unp;
2093 	struct vnode   *vp;
2094 
2095 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2096 
2097 	unp = VTOUNIONFS(ap->a_vp);
2098 	vp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
2099 
2100 #ifdef DIAGNOSTIC
2101 	if (vp == NULLVP)
2102 		panic("unionfs_strategy: nullvp");
2103 
2104 	if (ap->a_bp->b_iocmd == BIO_WRITE && vp == unp->un_lowervp)
2105 		panic("unionfs_strategy: writing to lowervp");
2106 #endif
2107 
2108 	return (VOP_STRATEGY(vp, ap->a_bp));
2109 }
2110 
2111 static int
2112 unionfs_getacl(struct vop_getacl_args *ap)
2113 {
2114 	int		error;
2115 	struct unionfs_node *unp;
2116 	struct vnode   *vp;
2117 
2118 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2119 
2120 	unp = VTOUNIONFS(ap->a_vp);
2121 	vp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
2122 
2123 	UNIONFS_INTERNAL_DEBUG("unionfs_getacl: enter\n");
2124 
2125 	error = VOP_GETACL(vp, ap->a_type, ap->a_aclp, ap->a_cred, ap->a_td);
2126 
2127 	UNIONFS_INTERNAL_DEBUG("unionfs_getacl: leave (%d)\n", error);
2128 
2129 	return (error);
2130 }
2131 
2132 static int
2133 unionfs_setacl(struct vop_setacl_args *ap)
2134 {
2135 	int		error;
2136 	struct unionfs_node *unp;
2137 	struct vnode   *uvp;
2138 	struct vnode   *lvp;
2139 	struct thread  *td;
2140 
2141 	UNIONFS_INTERNAL_DEBUG("unionfs_setacl: enter\n");
2142 
2143 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2144 
2145 	error = EROFS;
2146 	unp = VTOUNIONFS(ap->a_vp);
2147 	uvp = unp->un_uppervp;
2148 	lvp = unp->un_lowervp;
2149 	td = ap->a_td;
2150 
2151 	if (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)
2152 		return (EROFS);
2153 
2154 	if (uvp == NULLVP && lvp->v_type == VREG) {
2155 		if ((error = unionfs_copyfile(unp, 1, ap->a_cred, td)) != 0)
2156 			return (error);
2157 		uvp = unp->un_uppervp;
2158 	}
2159 
2160 	if (uvp != NULLVP)
2161 		error = VOP_SETACL(uvp, ap->a_type, ap->a_aclp, ap->a_cred, td);
2162 
2163 	UNIONFS_INTERNAL_DEBUG("unionfs_setacl: leave (%d)\n", error);
2164 
2165 	return (error);
2166 }
2167 
2168 static int
2169 unionfs_aclcheck(struct vop_aclcheck_args *ap)
2170 {
2171 	int		error;
2172 	struct unionfs_node *unp;
2173 	struct vnode   *vp;
2174 
2175 	UNIONFS_INTERNAL_DEBUG("unionfs_aclcheck: enter\n");
2176 
2177 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2178 
2179 	unp = VTOUNIONFS(ap->a_vp);
2180 	vp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
2181 
2182 	error = VOP_ACLCHECK(vp, ap->a_type, ap->a_aclp, ap->a_cred, ap->a_td);
2183 
2184 	UNIONFS_INTERNAL_DEBUG("unionfs_aclcheck: leave (%d)\n", error);
2185 
2186 	return (error);
2187 }
2188 
2189 static int
2190 unionfs_openextattr(struct vop_openextattr_args *ap)
2191 {
2192 	int		error;
2193 	struct unionfs_node *unp;
2194 	struct vnode   *vp;
2195 	struct vnode   *tvp;
2196 
2197 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2198 
2199 	vp = ap->a_vp;
2200 	unp = VTOUNIONFS(vp);
2201 	tvp = (unp->un_uppervp != NULLVP ? unp->un_uppervp : unp->un_lowervp);
2202 
2203 	if ((tvp == unp->un_uppervp && (unp->un_flag & UNIONFS_OPENEXTU)) ||
2204 	    (tvp == unp->un_lowervp && (unp->un_flag & UNIONFS_OPENEXTL)))
2205 		return (EBUSY);
2206 
2207 	error = VOP_OPENEXTATTR(tvp, ap->a_cred, ap->a_td);
2208 
2209 	if (error == 0) {
2210 		if (vn_lock(vp, LK_UPGRADE) != 0)
2211 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2212 		if (tvp == unp->un_uppervp)
2213 			unp->un_flag |= UNIONFS_OPENEXTU;
2214 		else
2215 			unp->un_flag |= UNIONFS_OPENEXTL;
2216 		vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
2217 	}
2218 
2219 	return (error);
2220 }
2221 
2222 static int
2223 unionfs_closeextattr(struct vop_closeextattr_args *ap)
2224 {
2225 	int		error;
2226 	struct unionfs_node *unp;
2227 	struct vnode   *vp;
2228 	struct vnode   *tvp;
2229 
2230 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2231 
2232 	vp = ap->a_vp;
2233 	unp = VTOUNIONFS(vp);
2234 	tvp = NULLVP;
2235 
2236 	if (unp->un_flag & UNIONFS_OPENEXTU)
2237 		tvp = unp->un_uppervp;
2238 	else if (unp->un_flag & UNIONFS_OPENEXTL)
2239 		tvp = unp->un_lowervp;
2240 
2241 	if (tvp == NULLVP)
2242 		return (EOPNOTSUPP);
2243 
2244 	error = VOP_CLOSEEXTATTR(tvp, ap->a_commit, ap->a_cred, ap->a_td);
2245 
2246 	if (error == 0) {
2247 		if (vn_lock(vp, LK_UPGRADE) != 0)
2248 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2249 		if (tvp == unp->un_uppervp)
2250 			unp->un_flag &= ~UNIONFS_OPENEXTU;
2251 		else
2252 			unp->un_flag &= ~UNIONFS_OPENEXTL;
2253 		vn_lock(vp, LK_DOWNGRADE | LK_RETRY);
2254 	}
2255 
2256 	return (error);
2257 }
2258 
2259 static int
2260 unionfs_getextattr(struct vop_getextattr_args *ap)
2261 {
2262 	struct unionfs_node *unp;
2263 	struct vnode   *vp;
2264 
2265 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2266 
2267 	unp = VTOUNIONFS(ap->a_vp);
2268 	vp = NULLVP;
2269 
2270 	if (unp->un_flag & UNIONFS_OPENEXTU)
2271 		vp = unp->un_uppervp;
2272 	else if (unp->un_flag & UNIONFS_OPENEXTL)
2273 		vp = unp->un_lowervp;
2274 
2275 	if (vp == NULLVP)
2276 		return (EOPNOTSUPP);
2277 
2278 	return (VOP_GETEXTATTR(vp, ap->a_attrnamespace, ap->a_name,
2279 	    ap->a_uio, ap->a_size, ap->a_cred, ap->a_td));
2280 }
2281 
2282 static int
2283 unionfs_setextattr(struct vop_setextattr_args *ap)
2284 {
2285 	int		error;
2286 	struct unionfs_node *unp;
2287 	struct vnode   *uvp;
2288 	struct vnode   *lvp;
2289 	struct vnode   *ovp;
2290 	struct ucred   *cred;
2291 	struct thread  *td;
2292 
2293 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2294 
2295 	error = EROFS;
2296 	unp = VTOUNIONFS(ap->a_vp);
2297 	uvp = unp->un_uppervp;
2298 	lvp = unp->un_lowervp;
2299 	ovp = NULLVP;
2300 	cred = ap->a_cred;
2301 	td = ap->a_td;
2302 
2303 	UNIONFS_INTERNAL_DEBUG("unionfs_setextattr: enter (un_flag=%x)\n", unp->un_flag);
2304 
2305 	if (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)
2306 		return (EROFS);
2307 
2308 	if (unp->un_flag & UNIONFS_OPENEXTU)
2309 		ovp = unp->un_uppervp;
2310 	else if (unp->un_flag & UNIONFS_OPENEXTL)
2311 		ovp = unp->un_lowervp;
2312 
2313 	if (ovp == NULLVP)
2314 		return (EOPNOTSUPP);
2315 
2316 	if (ovp == lvp && lvp->v_type == VREG) {
2317 		VOP_CLOSEEXTATTR(lvp, 0, cred, td);
2318 		if (uvp == NULLVP &&
2319 		    (error = unionfs_copyfile(unp, 1, cred, td)) != 0) {
2320 unionfs_setextattr_reopen:
2321 			if ((unp->un_flag & UNIONFS_OPENEXTL) &&
2322 			    VOP_OPENEXTATTR(lvp, cred, td)) {
2323 #ifdef DIAGNOSTIC
2324 				panic("unionfs: VOP_OPENEXTATTR failed");
2325 #endif
2326 				unp->un_flag &= ~UNIONFS_OPENEXTL;
2327 			}
2328 			goto unionfs_setextattr_abort;
2329 		}
2330 		uvp = unp->un_uppervp;
2331 		if ((error = VOP_OPENEXTATTR(uvp, cred, td)) != 0)
2332 			goto unionfs_setextattr_reopen;
2333 		unp->un_flag &= ~UNIONFS_OPENEXTL;
2334 		unp->un_flag |= UNIONFS_OPENEXTU;
2335 		ovp = uvp;
2336 	}
2337 
2338 	if (ovp == uvp)
2339 		error = VOP_SETEXTATTR(ovp, ap->a_attrnamespace, ap->a_name,
2340 		    ap->a_uio, cred, td);
2341 
2342 unionfs_setextattr_abort:
2343 	UNIONFS_INTERNAL_DEBUG("unionfs_setextattr: leave (%d)\n", error);
2344 
2345 	return (error);
2346 }
2347 
2348 static int
2349 unionfs_listextattr(struct vop_listextattr_args *ap)
2350 {
2351 	struct unionfs_node *unp;
2352 	struct vnode   *vp;
2353 
2354 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2355 
2356 	unp = VTOUNIONFS(ap->a_vp);
2357 	vp = NULLVP;
2358 
2359 	if (unp->un_flag & UNIONFS_OPENEXTU)
2360 		vp = unp->un_uppervp;
2361 	else if (unp->un_flag & UNIONFS_OPENEXTL)
2362 		vp = unp->un_lowervp;
2363 
2364 	if (vp == NULLVP)
2365 		return (EOPNOTSUPP);
2366 
2367 	return (VOP_LISTEXTATTR(vp, ap->a_attrnamespace, ap->a_uio,
2368 	    ap->a_size, ap->a_cred, ap->a_td));
2369 }
2370 
2371 static int
2372 unionfs_deleteextattr(struct vop_deleteextattr_args *ap)
2373 {
2374 	int		error;
2375 	struct unionfs_node *unp;
2376 	struct vnode   *uvp;
2377 	struct vnode   *lvp;
2378 	struct vnode   *ovp;
2379 	struct ucred   *cred;
2380 	struct thread  *td;
2381 
2382 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2383 
2384 	error = EROFS;
2385 	unp = VTOUNIONFS(ap->a_vp);
2386 	uvp = unp->un_uppervp;
2387 	lvp = unp->un_lowervp;
2388 	ovp = NULLVP;
2389 	cred = ap->a_cred;
2390 	td = ap->a_td;
2391 
2392 	UNIONFS_INTERNAL_DEBUG("unionfs_deleteextattr: enter (un_flag=%x)\n", unp->un_flag);
2393 
2394 	if (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)
2395 		return (EROFS);
2396 
2397 	if (unp->un_flag & UNIONFS_OPENEXTU)
2398 		ovp = unp->un_uppervp;
2399 	else if (unp->un_flag & UNIONFS_OPENEXTL)
2400 		ovp = unp->un_lowervp;
2401 
2402 	if (ovp == NULLVP)
2403 		return (EOPNOTSUPP);
2404 
2405 	if (ovp == lvp && lvp->v_type == VREG) {
2406 		VOP_CLOSEEXTATTR(lvp, 0, cred, td);
2407 		if (uvp == NULLVP &&
2408 		    (error = unionfs_copyfile(unp, 1, cred, td)) != 0) {
2409 unionfs_deleteextattr_reopen:
2410 			if ((unp->un_flag & UNIONFS_OPENEXTL) &&
2411 			    VOP_OPENEXTATTR(lvp, cred, td)) {
2412 #ifdef DIAGNOSTIC
2413 				panic("unionfs: VOP_OPENEXTATTR failed");
2414 #endif
2415 				unp->un_flag &= ~UNIONFS_OPENEXTL;
2416 			}
2417 			goto unionfs_deleteextattr_abort;
2418 		}
2419 		uvp = unp->un_uppervp;
2420 		if ((error = VOP_OPENEXTATTR(uvp, cred, td)) != 0)
2421 			goto unionfs_deleteextattr_reopen;
2422 		unp->un_flag &= ~UNIONFS_OPENEXTL;
2423 		unp->un_flag |= UNIONFS_OPENEXTU;
2424 		ovp = uvp;
2425 	}
2426 
2427 	if (ovp == uvp)
2428 		error = VOP_DELETEEXTATTR(ovp, ap->a_attrnamespace, ap->a_name,
2429 		    ap->a_cred, ap->a_td);
2430 
2431 unionfs_deleteextattr_abort:
2432 	UNIONFS_INTERNAL_DEBUG("unionfs_deleteextattr: leave (%d)\n", error);
2433 
2434 	return (error);
2435 }
2436 
2437 static int
2438 unionfs_setlabel(struct vop_setlabel_args *ap)
2439 {
2440 	int		error;
2441 	struct unionfs_node *unp;
2442 	struct vnode   *uvp;
2443 	struct vnode   *lvp;
2444 	struct thread  *td;
2445 
2446 	UNIONFS_INTERNAL_DEBUG("unionfs_setlabel: enter\n");
2447 
2448 	KASSERT_UNIONFS_VNODE(ap->a_vp);
2449 
2450 	error = EROFS;
2451 	unp = VTOUNIONFS(ap->a_vp);
2452 	uvp = unp->un_uppervp;
2453 	lvp = unp->un_lowervp;
2454 	td = ap->a_td;
2455 
2456 	if (ap->a_vp->v_mount->mnt_flag & MNT_RDONLY)
2457 		return (EROFS);
2458 
2459 	if (uvp == NULLVP && lvp->v_type == VREG) {
2460 		if ((error = unionfs_copyfile(unp, 1, ap->a_cred, td)) != 0)
2461 			return (error);
2462 		uvp = unp->un_uppervp;
2463 	}
2464 
2465 	if (uvp != NULLVP)
2466 		error = VOP_SETLABEL(uvp, ap->a_label, ap->a_cred, td);
2467 
2468 	UNIONFS_INTERNAL_DEBUG("unionfs_setlabel: leave (%d)\n", error);
2469 
2470 	return (error);
2471 }
2472 
2473 static int
2474 unionfs_vptofh(struct vop_vptofh_args *ap)
2475 {
2476 	return (EOPNOTSUPP);
2477 }
2478 
2479 static int
2480 unionfs_add_writecount(struct vop_add_writecount_args *ap)
2481 {
2482 	struct vnode *tvp, *vp;
2483 	struct unionfs_node *unp;
2484 	int error;
2485 
2486 	vp = ap->a_vp;
2487 	unp = VTOUNIONFS(vp);
2488 	tvp = unp->un_uppervp != NULL ? unp->un_uppervp : unp->un_lowervp;
2489 	VI_LOCK(vp);
2490 	/* text refs are bypassed to lowervp */
2491 	VNASSERT(vp->v_writecount >= 0, vp, ("wrong null writecount"));
2492 	VNASSERT(vp->v_writecount + ap->a_inc >= 0, vp,
2493 	    ("wrong writecount inc %d", ap->a_inc));
2494 	if (tvp != NULL)
2495 		error = VOP_ADD_WRITECOUNT(tvp, ap->a_inc);
2496 	else if (vp->v_writecount < 0)
2497 		error = ETXTBSY;
2498 	else
2499 		error = 0;
2500 	if (error == 0)
2501 		vp->v_writecount += ap->a_inc;
2502 	VI_UNLOCK(vp);
2503 	return (error);
2504 }
2505 
2506 struct vop_vector unionfs_vnodeops = {
2507 	.vop_default =		&default_vnodeops,
2508 
2509 	.vop_access =		unionfs_access,
2510 	.vop_aclcheck =		unionfs_aclcheck,
2511 	.vop_advlock =		unionfs_advlock,
2512 	.vop_bmap =		VOP_EOPNOTSUPP,
2513 	.vop_cachedlookup =	unionfs_lookup,
2514 	.vop_close =		unionfs_close,
2515 	.vop_closeextattr =	unionfs_closeextattr,
2516 	.vop_create =		unionfs_create,
2517 	.vop_deleteextattr =	unionfs_deleteextattr,
2518 	.vop_fsync =		unionfs_fsync,
2519 	.vop_getacl =		unionfs_getacl,
2520 	.vop_getattr =		unionfs_getattr,
2521 	.vop_getextattr =	unionfs_getextattr,
2522 	.vop_getwritemount =	unionfs_getwritemount,
2523 	.vop_inactive =		unionfs_inactive,
2524 	.vop_need_inactive =	vop_stdneed_inactive,
2525 	.vop_islocked =		unionfs_islocked,
2526 	.vop_ioctl =		unionfs_ioctl,
2527 	.vop_link =		unionfs_link,
2528 	.vop_listextattr =	unionfs_listextattr,
2529 	.vop_lock1 =		unionfs_lock,
2530 	.vop_lookup =		vfs_cache_lookup,
2531 	.vop_mkdir =		unionfs_mkdir,
2532 	.vop_mknod =		unionfs_mknod,
2533 	.vop_open =		unionfs_open,
2534 	.vop_openextattr =	unionfs_openextattr,
2535 	.vop_pathconf =		unionfs_pathconf,
2536 	.vop_poll =		unionfs_poll,
2537 	.vop_print =		unionfs_print,
2538 	.vop_read =		unionfs_read,
2539 	.vop_readdir =		unionfs_readdir,
2540 	.vop_readlink =		unionfs_readlink,
2541 	.vop_reclaim =		unionfs_reclaim,
2542 	.vop_remove =		unionfs_remove,
2543 	.vop_rename =		unionfs_rename,
2544 	.vop_rmdir =		unionfs_rmdir,
2545 	.vop_setacl =		unionfs_setacl,
2546 	.vop_setattr =		unionfs_setattr,
2547 	.vop_setextattr =	unionfs_setextattr,
2548 	.vop_setlabel =		unionfs_setlabel,
2549 	.vop_strategy =		unionfs_strategy,
2550 	.vop_symlink =		unionfs_symlink,
2551 	.vop_unlock =		unionfs_unlock,
2552 	.vop_whiteout =		unionfs_whiteout,
2553 	.vop_write =		unionfs_write,
2554 	.vop_vptofh =		unionfs_vptofh,
2555 	.vop_add_writecount =	unionfs_add_writecount,
2556 };
2557 VFS_VOP_VECTOR_REGISTER(unionfs_vnodeops);
2558