xref: /netbsd-src/sys/miscfs/umapfs/umap_vnops.c (revision b7ae68fde0d8ef1c03714e8bbb1ee7c6118ea93b)
1 /*	$NetBSD: umap_vnops.c,v 1.41 2006/09/13 10:07:42 elad Exp $	*/
2 
3 /*
4  * Copyright (c) 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software donated to Berkeley by
8  * the UCLA Ficus project.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)umap_vnops.c	8.6 (Berkeley) 5/22/95
35  */
36 
37 /*
38  * Umap Layer
39  */
40 
41 #include <sys/cdefs.h>
42 __KERNEL_RCSID(0, "$NetBSD: umap_vnops.c,v 1.41 2006/09/13 10:07:42 elad Exp $");
43 
44 #include <sys/param.h>
45 #include <sys/systm.h>
46 #include <sys/time.h>
47 #include <sys/vnode.h>
48 #include <sys/mount.h>
49 #include <sys/namei.h>
50 #include <sys/malloc.h>
51 #include <sys/buf.h>
52 #include <sys/kauth.h>
53 
54 #include <miscfs/umapfs/umap.h>
55 #include <miscfs/genfs/genfs.h>
56 #include <miscfs/genfs/layer_extern.h>
57 
58 int	umap_lookup(void *);
59 int	umap_getattr(void *);
60 int	umap_print(void *);
61 int	umap_rename(void *);
62 
63 /*
64  * Global vfs data structures
65  */
66 /*
67  * XXX - strategy, bwrite are hand coded currently.  They should
68  * go away with a merged buffer/block cache.
69  *
70  */
71 int (**umap_vnodeop_p)(void *);
72 const struct vnodeopv_entry_desc umap_vnodeop_entries[] = {
73 	{ &vop_default_desc,	umap_bypass },
74 
75 	{ &vop_lookup_desc,	umap_lookup },
76 	{ &vop_getattr_desc,	umap_getattr },
77 	{ &vop_print_desc,	umap_print },
78 	{ &vop_rename_desc,	umap_rename },
79 
80 	{ &vop_lock_desc,	layer_lock },
81 	{ &vop_unlock_desc,	layer_unlock },
82 	{ &vop_islocked_desc,	layer_islocked },
83 	{ &vop_fsync_desc,	layer_fsync },
84 	{ &vop_inactive_desc,	layer_inactive },
85 	{ &vop_reclaim_desc,	layer_reclaim },
86 	{ &vop_open_desc,	layer_open },
87 	{ &vop_setattr_desc,	layer_setattr },
88 	{ &vop_access_desc,	layer_access },
89 	{ &vop_remove_desc,	layer_remove },
90 	{ &vop_rmdir_desc,	layer_rmdir },
91 
92 	{ &vop_bwrite_desc,	layer_bwrite },
93 	{ &vop_bmap_desc,	layer_bmap },
94 	{ &vop_getpages_desc,	layer_getpages },
95 	{ &vop_putpages_desc,	layer_putpages },
96 
97 	{ NULL, NULL }
98 };
99 const struct vnodeopv_desc umapfs_vnodeop_opv_desc =
100 	{ &umap_vnodeop_p, umap_vnodeop_entries };
101 
102 /*
103  * This is the 08-June-1999 bypass routine.
104  * See layer_vnops.c:layer_bypass for more details.
105  */
106 int
107 umap_bypass(v)
108 	void *v;
109 {
110 	struct vop_generic_args /* {
111 		struct vnodeop_desc *a_desc;
112 		<other random data follows, presumably>
113 	} */ *ap = v;
114 	int (**our_vnodeop_p)(void *);
115 	kauth_cred_t *credpp = NULL, credp = 0;
116 	kauth_cred_t savecredp = 0, savecompcredp = 0;
117 	kauth_cred_t compcredp = 0;
118 	struct vnode **this_vp_p;
119 	int error, error1;
120 	struct vnode *old_vps[VDESC_MAX_VPS], *vp0;
121 	struct vnode **vps_p[VDESC_MAX_VPS];
122 	struct vnode ***vppp;
123 	struct vnodeop_desc *descp = ap->a_desc;
124 	int reles, i, flags;
125 	struct componentname **compnamepp = 0;
126 
127 #ifdef SAFETY
128 	/*
129 	 * We require at least one vp.
130 	 */
131 	if (descp->vdesc_vp_offsets == NULL ||
132 	    descp->vdesc_vp_offsets[0] == VDESC_NO_OFFSET)
133 		panic("%s: no vp's in map.\n", __func__);
134 #endif
135 
136 	vps_p[0] =
137 	    VOPARG_OFFSETTO(struct vnode**, descp->vdesc_vp_offsets[0], ap);
138 	vp0 = *vps_p[0];
139 	flags = MOUNTTOUMAPMOUNT(vp0->v_mount)->umapm_flags;
140 	our_vnodeop_p = vp0->v_op;
141 
142 	if (flags & LAYERFS_MBYPASSDEBUG)
143 		printf("%s: %s\n", __func__, descp->vdesc_name);
144 
145 	/*
146 	 * Map the vnodes going in.
147 	 * Later, we'll invoke the operation based on
148 	 * the first mapped vnode's operation vector.
149 	 */
150 	reles = descp->vdesc_flags;
151 	for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
152 		if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
153 			break;   /* bail out at end of list */
154 		vps_p[i] = this_vp_p =
155 		    VOPARG_OFFSETTO(struct vnode**, descp->vdesc_vp_offsets[i],
156 		    ap);
157 		/*
158 		 * We're not guaranteed that any but the first vnode
159 		 * are of our type.  Check for and don't map any
160 		 * that aren't.  (We must always map first vp or vclean fails.)
161 		 */
162 		if (i && (*this_vp_p == NULL ||
163 		    (*this_vp_p)->v_op != our_vnodeop_p)) {
164 			old_vps[i] = NULL;
165 		} else {
166 			old_vps[i] = *this_vp_p;
167 			*(vps_p[i]) = UMAPVPTOLOWERVP(*this_vp_p);
168 			/*
169 			 * XXX - Several operations have the side effect
170 			 * of vrele'ing their vp's.  We must account for
171 			 * that.  (This should go away in the future.)
172 			 */
173 			if (reles & VDESC_VP0_WILLRELE)
174 				VREF(*this_vp_p);
175 		}
176 
177 	}
178 
179 	/*
180 	 * Fix the credentials.  (That's the purpose of this layer.)
181 	 */
182 
183 	if (descp->vdesc_cred_offset != VDESC_NO_OFFSET) {
184 
185 		credpp = VOPARG_OFFSETTO(kauth_cred_t*,
186 		    descp->vdesc_cred_offset, ap);
187 
188 		/* Save old values */
189 
190 		savecredp = *credpp;
191 		if (savecredp != NOCRED)
192 			*credpp = kauth_cred_dup(savecredp);
193 		credp = *credpp;
194 
195 		if ((flags & LAYERFS_MBYPASSDEBUG) &&
196 		    kauth_authorize_generic(credp, KAUTH_GENERIC_ISSUSER,
197 		     NULL))
198 			printf("umap_bypass: user was %d, group %d\n",
199 			    kauth_cred_geteuid(credp), kauth_cred_getegid(credp));
200 
201 		/* Map all ids in the credential structure. */
202 
203 		umap_mapids(vp0->v_mount, credp);
204 
205 		if ((flags & LAYERFS_MBYPASSDEBUG) &&
206 		    kauth_authorize_generic(credp, KAUTH_GENERIC_ISSUSER,
207 		     NULL))
208 			printf("umap_bypass: user now %d, group %d\n",
209 			    kauth_cred_geteuid(credp), kauth_cred_getegid(credp));
210 	}
211 
212 	/* BSD often keeps a credential in the componentname structure
213 	 * for speed.  If there is one, it better get mapped, too.
214 	 */
215 
216 	if (descp->vdesc_componentname_offset != VDESC_NO_OFFSET) {
217 
218 		compnamepp = VOPARG_OFFSETTO(struct componentname**,
219 		    descp->vdesc_componentname_offset, ap);
220 
221 		savecompcredp = (*compnamepp)->cn_cred;
222 		if (savecompcredp != NOCRED)
223 			(*compnamepp)->cn_cred = kauth_cred_dup(savecompcredp);
224 		compcredp = (*compnamepp)->cn_cred;
225 
226 		if ((flags & LAYERFS_MBYPASSDEBUG) &&
227 		    kauth_authorize_generic(compcredp, KAUTH_GENERIC_ISSUSER,
228 		     NULL))
229 			printf("umap_bypass: component credit user was %d, group %d\n",
230 			    kauth_cred_geteuid(compcredp), kauth_cred_getegid(compcredp));
231 
232 		/* Map all ids in the credential structure. */
233 
234 		umap_mapids(vp0->v_mount, compcredp);
235 
236 		if ((flags & LAYERFS_MBYPASSDEBUG) &&
237 		    kauth_authorize_generic(compcredp, KAUTH_GENERIC_ISSUSER,
238 		     NULL))
239 			printf("umap_bypass: component credit user now %d, group %d\n",
240 			    kauth_cred_geteuid(compcredp), kauth_cred_getegid(compcredp));
241 	}
242 
243 	/*
244 	 * Call the operation on the lower layer
245 	 * with the modified argument structure.
246 	 */
247 	error = VCALL(*vps_p[0], descp->vdesc_offset, ap);
248 
249 	/*
250 	 * Maintain the illusion of call-by-value
251 	 * by restoring vnodes in the argument structure
252 	 * to their original value.
253 	 */
254 	reles = descp->vdesc_flags;
255 	for (i = 0; i < VDESC_MAX_VPS; reles >>= 1, i++) {
256 		if (descp->vdesc_vp_offsets[i] == VDESC_NO_OFFSET)
257 			break;   /* bail out at end of list */
258 		if (old_vps[i]) {
259 			*(vps_p[i]) = old_vps[i];
260 			if (reles & VDESC_VP0_WILLUNLOCK)
261 				LAYERFS_UPPERUNLOCK(*(vps_p[i]), 0, error1);
262 			if (reles & VDESC_VP0_WILLRELE)
263 				vrele(*(vps_p[i]));
264 		}
265 	}
266 
267 	/*
268 	 * Map the possible out-going vpp
269 	 * (Assumes that the lower layer always returns
270 	 * a VREF'ed vpp unless it gets an error.)
271 	 */
272 	if (descp->vdesc_vpp_offset != VDESC_NO_OFFSET &&
273 	    !(descp->vdesc_flags & VDESC_NOMAP_VPP) &&
274 	    !error) {
275 		/*
276 		 * XXX - even though some ops have vpp returned vp's,
277 		 * several ops actually vrele this before returning.
278 		 * We must avoid these ops.
279 		 * (This should go away when these ops are regularized.)
280 		 */
281 		if (descp->vdesc_flags & VDESC_VPP_WILLRELE)
282 			goto out;
283 		vppp = VOPARG_OFFSETTO(struct vnode***,
284 				 descp->vdesc_vpp_offset, ap);
285 		/*
286 		 * Only vop_lookup, vop_create, vop_makedir, vop_bmap,
287 		 * vop_mknod, and vop_symlink return vpp's. vop_bmap
288 		 * doesn't call bypass as the lower vpp is fine (we're just
289 		 * going to do i/o on it). vop_lookup doesn't call bypass
290 		 * as a lookup on "." would generate a locking error.
291 		 * So all the calls which get us here have a locked vpp. :-)
292 		 */
293 		error = layer_node_create(old_vps[0]->v_mount, **vppp, *vppp);
294 		if (error) {
295 			vput(**vppp);
296 			**vppp = NULL;
297 		}
298 	}
299 
300  out:
301 	/*
302 	 * Free duplicate cred structure and restore old one.
303 	 */
304 	if (descp->vdesc_cred_offset != VDESC_NO_OFFSET) {
305 		if ((flags & LAYERFS_MBYPASSDEBUG) && credp &&
306 		    kauth_cred_geteuid(credp) != 0)
307 			printf("umap_bypass: returning-user was %d\n",
308 			    kauth_cred_geteuid(credp));
309 
310 		if (savecredp != NOCRED && credpp) {
311 			kauth_cred_free(credp);
312 			*credpp = savecredp;
313 			if ((flags & LAYERFS_MBYPASSDEBUG) && credpp &&
314 			    kauth_authorize_generic(*credpp,
315 			     KAUTH_GENERIC_ISSUSER,NULL))
316 			 	printf("umap_bypass: returning-user now %d\n\n",
317 				    kauth_cred_geteuid(savecredp));
318 		}
319 	}
320 
321 	if (descp->vdesc_componentname_offset != VDESC_NO_OFFSET) {
322 		if ((flags & LAYERFS_MBYPASSDEBUG) && compcredp &&
323 		    kauth_authorize_generic(compcredp, KAUTH_GENERIC_ISSUSER,
324 		     NULL))
325 			printf("umap_bypass: returning-component-user was %d\n",
326 			    kauth_cred_geteuid(compcredp));
327 
328 		if (savecompcredp != NOCRED) {
329 			kauth_cred_free(compcredp);
330 			(*compnamepp)->cn_cred = savecompcredp;
331 			if ((flags & LAYERFS_MBYPASSDEBUG) && savecompcredp &&
332 			    kauth_authorize_generic(savecompcredp,
333 			     KAUTH_GENERIC_ISSUSER, NULL))
334 			 	printf("umap_bypass: returning-component-user now %d\n",
335 				    kauth_cred_geteuid(savecompcredp));
336 		}
337 	}
338 
339 	return (error);
340 }
341 
342 /*
343  * This is based on the 08-June-1999 bypass routine.
344  * See layer_vnops.c:layer_bypass for more details.
345  */
346 int
347 umap_lookup(v)
348 	void *v;
349 {
350 	struct vop_lookup_args /* {
351 		struct vnodeop_desc *a_desc;
352 		struct vnode * a_dvp;
353 		struct vnode ** a_vpp;
354 		struct componentname * a_cnp;
355 	} */ *ap = v;
356 	struct componentname *cnp = ap->a_cnp;
357 	kauth_cred_t savecompcredp = NULL;
358 	kauth_cred_t compcredp = NULL;
359 	struct vnode *dvp, *vp, *ldvp;
360 	struct mount *mp;
361 	int error;
362 	int i, flags, cnf = cnp->cn_flags;
363 
364 	dvp = ap->a_dvp;
365 	mp = dvp->v_mount;
366 
367 	if ((cnf & ISLASTCN) && (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
368 		(cnp->cn_nameiop == DELETE || cnp->cn_nameiop == RENAME))
369 		return (EROFS);
370 
371 	flags = MOUNTTOUMAPMOUNT(mp)->umapm_flags;
372 	ldvp = UMAPVPTOLOWERVP(dvp);
373 
374 	if (flags & LAYERFS_MBYPASSDEBUG)
375 		printf("umap_lookup\n");
376 
377 	/*
378 	 * Fix the credentials.  (That's the purpose of this layer.)
379 	 *
380 	 * BSD often keeps a credential in the componentname structure
381 	 * for speed.  If there is one, it better get mapped, too.
382 	 */
383 
384 	if ((savecompcredp = cnp->cn_cred)) {
385 		compcredp = kauth_cred_dup(savecompcredp);
386 		cnp->cn_cred = compcredp;
387 
388 		if ((flags & LAYERFS_MBYPASSDEBUG) &&
389 		    kauth_authorize_generic(compcredp, KAUTH_GENERIC_ISSUSER,
390 		     NULL))
391 			printf("umap_lookup: component credit user was %d, group %d\n",
392 			    kauth_cred_geteuid(compcredp), kauth_cred_getegid(compcredp));
393 
394 		/* Map all ids in the credential structure. */
395 		umap_mapids(mp, compcredp);
396 	}
397 
398 	if ((flags & LAYERFS_MBYPASSDEBUG) && compcredp &&
399 	    kauth_authorize_generic(compcredp, KAUTH_GENERIC_ISSUSER,
400 	     NULL))
401 		printf("umap_lookup: component credit user now %d, group %d\n",
402 		    kauth_cred_geteuid(compcredp), kauth_cred_getegid(compcredp));
403 
404 	ap->a_dvp = ldvp;
405 	error = VCALL(ldvp, ap->a_desc->vdesc_offset, ap);
406 	vp = *ap->a_vpp;
407 	*ap->a_vpp = NULL;
408 
409 	if (error == EJUSTRETURN && (cnf & ISLASTCN) &&
410 	    (dvp->v_mount->mnt_flag & MNT_RDONLY) &&
411 	    (cnp->cn_nameiop == CREATE || cnp->cn_nameiop == RENAME))
412 		error = EROFS;
413 
414 	/* Do locking fixup as appropriate. See layer_lookup() for info */
415 	if ((cnp->cn_flags & PDIRUNLOCK)) {
416 		LAYERFS_UPPERUNLOCK(dvp, 0, i);
417 	}
418 	if (ldvp == vp) {
419 		*ap->a_vpp = dvp;
420 		VREF(dvp);
421 		vrele(vp);
422 	} else if (vp != NULL) {
423 		error = layer_node_create(mp, vp, ap->a_vpp);
424 		if (error) {
425 			vput(vp);
426 			if (cnp->cn_flags & PDIRUNLOCK) {
427 				if (vn_lock(dvp, LK_EXCLUSIVE | LK_RETRY) == 0)
428 					cnp->cn_flags &= ~PDIRUNLOCK;
429 			}
430 		}
431 	}
432 
433 	/*
434 	 * Free duplicate cred structure and restore old one.
435 	 */
436 	if ((flags & LAYERFS_MBYPASSDEBUG) && compcredp &&
437 	    kauth_authorize_generic(compcredp, KAUTH_GENERIC_ISSUSER,
438 	     NULL))
439 		printf("umap_lookup: returning-component-user was %d\n",
440 			    kauth_cred_geteuid(compcredp));
441 
442 	if (savecompcredp != NOCRED) {
443 		if (compcredp)
444 			kauth_cred_free(compcredp);
445 		cnp->cn_cred = savecompcredp;
446 		if ((flags & LAYERFS_MBYPASSDEBUG) && savecompcredp &&
447 		    kauth_authorize_generic(savecompcredp,
448 		     KAUTH_GENERIC_ISSUSER, NULL))
449 		 	printf("umap_lookup: returning-component-user now %d\n",
450 			    kauth_cred_geteuid(savecompcredp));
451 	}
452 
453 	return (error);
454 }
455 
456 /*
457  *  We handle getattr to change the fsid.
458  */
459 int
460 umap_getattr(v)
461 	void *v;
462 {
463 	struct vop_getattr_args /* {
464 		struct vnode *a_vp;
465 		struct vattr *a_vap;
466 		kauth_cred_t a_cred;
467 		struct lwp *a_l;
468 	} */ *ap = v;
469 	uid_t uid;
470 	gid_t gid;
471 	int error, tmpid, nentries, gnentries, flags;
472 	u_long (*mapdata)[2];
473 	u_long (*gmapdata)[2];
474 	struct vnode **vp1p;
475 	const struct vnodeop_desc *descp = ap->a_desc;
476 
477 	if ((error = umap_bypass(ap)) != 0)
478 		return (error);
479 	/* Requires that arguments be restored. */
480 	ap->a_vap->va_fsid = ap->a_vp->v_mount->mnt_stat.f_fsidx.__fsid_val[0];
481 
482 	flags = MOUNTTOUMAPMOUNT(ap->a_vp->v_mount)->umapm_flags;
483 	/*
484 	 * Umap needs to map the uid and gid returned by a stat
485 	 * into the proper values for this site.  This involves
486 	 * finding the returned uid in the mapping information,
487 	 * translating it into the uid on the other end,
488 	 * and filling in the proper field in the vattr
489 	 * structure pointed to by ap->a_vap.  The group
490 	 * is easier, since currently all groups will be
491 	 * translate to the NULLGROUP.
492 	 */
493 
494 	/* Find entry in map */
495 
496 	uid = ap->a_vap->va_uid;
497 	gid = ap->a_vap->va_gid;
498 	if ((flags & LAYERFS_MBYPASSDEBUG))
499 		printf("umap_getattr: mapped uid = %d, mapped gid = %d\n", uid,
500 		    gid);
501 
502 	vp1p = VOPARG_OFFSETTO(struct vnode**, descp->vdesc_vp_offsets[0], ap);
503 	nentries =  MOUNTTOUMAPMOUNT((*vp1p)->v_mount)->info_nentries;
504 	mapdata =  (MOUNTTOUMAPMOUNT((*vp1p)->v_mount)->info_mapdata);
505 	gnentries =  MOUNTTOUMAPMOUNT((*vp1p)->v_mount)->info_gnentries;
506 	gmapdata =  (MOUNTTOUMAPMOUNT((*vp1p)->v_mount)->info_gmapdata);
507 
508 	/* Reverse map the uid for the vnode.  Since it's a reverse
509 		map, we can't use umap_mapids() to do it. */
510 
511 	tmpid = umap_reverse_findid(uid, mapdata, nentries);
512 
513 	if (tmpid != -1) {
514 		ap->a_vap->va_uid = (uid_t) tmpid;
515 		if ((flags & LAYERFS_MBYPASSDEBUG))
516 			printf("umap_getattr: original uid = %d\n", uid);
517 	} else
518 		ap->a_vap->va_uid = (uid_t) NOBODY;
519 
520 	/* Reverse map the gid for the vnode. */
521 
522 	tmpid = umap_reverse_findid(gid, gmapdata, gnentries);
523 
524 	if (tmpid != -1) {
525 		ap->a_vap->va_gid = (gid_t) tmpid;
526 		if ((flags & LAYERFS_MBYPASSDEBUG))
527 			printf("umap_getattr: original gid = %d\n", gid);
528 	} else
529 		ap->a_vap->va_gid = (gid_t) NULLGROUP;
530 
531 	return (0);
532 }
533 
534 int
535 umap_print(v)
536 	void *v;
537 {
538 	struct vop_print_args /* {
539 		struct vnode *a_vp;
540 	} */ *ap = v;
541 	struct vnode *vp = ap->a_vp;
542 	printf("\ttag VT_UMAPFS, vp=%p, lowervp=%p\n", vp,
543 	    UMAPVPTOLOWERVP(vp));
544 	return (0);
545 }
546 
547 int
548 umap_rename(v)
549 	void *v;
550 {
551 	struct vop_rename_args  /* {
552 		struct vnode *a_fdvp;
553 		struct vnode *a_fvp;
554 		struct componentname *a_fcnp;
555 		struct vnode *a_tdvp;
556 		struct vnode *a_tvp;
557 		struct componentname *a_tcnp;
558 	} */ *ap = v;
559 	int error, flags;
560 	struct componentname *compnamep;
561 	kauth_cred_t compcredp, savecompcredp;
562 	struct vnode *vp;
563 	struct vnode *tvp;
564 
565 	/*
566 	 * Rename is irregular, having two componentname structures.
567 	 * We need to map the cre in the second structure,
568 	 * and then bypass takes care of the rest.
569 	 */
570 
571 	vp = ap->a_fdvp;
572 	flags = MOUNTTOUMAPMOUNT(vp->v_mount)->umapm_flags;
573 	compnamep = ap->a_tcnp;
574 	compcredp = compnamep->cn_cred;
575 
576 	savecompcredp = compcredp;
577 	compcredp = compnamep->cn_cred = kauth_cred_dup(savecompcredp);
578 
579 	if ((flags & LAYERFS_MBYPASSDEBUG) &&
580 	    kauth_authorize_generic(compcredp, KAUTH_GENERIC_ISSUSER,
581 	     NULL))
582 		printf("umap_rename: rename component credit user was %d, group %d\n",
583 		    kauth_cred_geteuid(compcredp), kauth_cred_getegid(compcredp));
584 
585 	/* Map all ids in the credential structure. */
586 
587 	umap_mapids(vp->v_mount, compcredp);
588 
589 	if ((flags & LAYERFS_MBYPASSDEBUG) &&
590 	    kauth_authorize_generic(compcredp, KAUTH_GENERIC_ISSUSER,
591 	     NULL))
592 		printf("umap_rename: rename component credit user now %d, group %d\n",
593 		    kauth_cred_geteuid(compcredp), kauth_cred_getegid(compcredp));
594 
595 	tvp = ap->a_tvp;
596 	if (tvp) {
597 		if (tvp->v_mount != vp->v_mount)
598 			tvp = NULL;
599 		else
600 			vref(tvp);
601 	}
602 	error = umap_bypass(ap);
603 	if (tvp) {
604 		if (error == 0)
605 			VTOLAYER(tvp)->layer_flags |= LAYERFS_REMOVED;
606 		vrele(tvp);
607 	}
608 
609 	/* Restore the additional mapped componentname cred structure. */
610 
611 	kauth_cred_free(compcredp);
612 	compnamep->cn_cred = savecompcredp;
613 
614 	return error;
615 }
616