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      1 /*	$NetBSD: tmpfs_rename.c,v 1.12 2021/10/20 14:28:21 thorpej Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2012 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R Campbell.
      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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * tmpfs rename
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 __KERNEL_RCSID(0, "$NetBSD: tmpfs_rename.c,v 1.12 2021/10/20 14:28:21 thorpej Exp $");
     38 
     39 #include <sys/param.h>
     40 #include <sys/errno.h>
     41 #include <sys/kauth.h>
     42 #include <sys/mount.h>
     43 #include <sys/namei.h>
     44 #include <sys/stat.h>
     45 #include <sys/vnode.h>
     46 #include <sys/vnode_if.h>
     47 
     48 #include <miscfs/genfs/genfs.h>
     49 
     50 #include <fs/tmpfs/tmpfs_vnops.h>
     51 #include <fs/tmpfs/tmpfs.h>
     52 
     53 /*
     54  * Forward declarations
     55  */
     56 
     57 static int tmpfs_sane_rename(struct vnode *, struct componentname *,
     58     struct vnode *, struct componentname *,
     59     kauth_cred_t, bool);
     60 static bool tmpfs_rmdired_p(struct vnode *);
     61 static int tmpfs_gro_lock_directory(struct mount *, struct vnode *);
     62 
     63 static const struct genfs_rename_ops tmpfs_genfs_rename_ops;
     64 
     65 /*
     66  * tmpfs_sane_rename: The hairiest vop, with the saner API.
     67  *
     68  * Arguments:
     69  *
     70  * . fdvp (from directory vnode),
     71  * . fcnp (from component name),
     72  * . tdvp (to directory vnode),
     73  * . tcnp (to component name),
     74  * . cred (credentials structure), and
     75  * . posixly_correct (flag for behaviour if target & source link same file).
     76  *
     77  * fdvp and tdvp may be the same, and must be referenced and unlocked.
     78  */
     79 static int
     80 tmpfs_sane_rename(
     81     struct vnode *fdvp, struct componentname *fcnp,
     82     struct vnode *tdvp, struct componentname *tcnp,
     83     kauth_cred_t cred, bool posixly_correct)
     84 {
     85 	struct tmpfs_dirent *fdirent, *tdirent;
     86 
     87 	return genfs_sane_rename(&tmpfs_genfs_rename_ops,
     88 	    fdvp, fcnp, &fdirent, tdvp, tcnp, &tdirent,
     89 	    cred, posixly_correct);
     90 }
     91 
     92 /*
     93  * tmpfs_rename: The hairiest vop, with the insanest API.  Defer to
     94  * genfs_insane_rename immediately.
     95  */
     96 int
     97 tmpfs_rename(void *v)
     98 {
     99 
    100 	return genfs_insane_rename(v, &tmpfs_sane_rename);
    101 }
    102 
    103 /*
    104  * tmpfs_gro_directory_empty_p: Return true if the directory vp is
    105  * empty.  dvp is its parent.
    106  *
    107  * vp and dvp must be locked and referenced.
    108  */
    109 static bool
    110 tmpfs_gro_directory_empty_p(struct mount *mp, kauth_cred_t cred,
    111     struct vnode *vp, struct vnode *dvp)
    112 {
    113 
    114 	(void)mp;
    115 	(void)cred;
    116 	(void)dvp;
    117 	KASSERT(mp != NULL);
    118 	KASSERT(vp != NULL);
    119 	KASSERT(dvp != NULL);
    120 	KASSERT(vp != dvp);
    121 	KASSERT(vp->v_mount == mp);
    122 	KASSERT(dvp->v_mount == mp);
    123 	KASSERT(VOP_ISLOCKED(vp) == LK_EXCLUSIVE);
    124 	KASSERT(VOP_ISLOCKED(dvp) == LK_EXCLUSIVE);
    125 
    126 	return (VP_TO_TMPFS_NODE(vp)->tn_size == 0);
    127 }
    128 
    129 /*
    130  * tmpfs_gro_rename_check_possible: Check whether a rename is possible
    131  * independent of credentials.
    132  */
    133 static int
    134 tmpfs_gro_rename_check_possible(struct mount *mp,
    135     struct vnode *fdvp, struct vnode *fvp,
    136     struct vnode *tdvp, struct vnode *tvp)
    137 {
    138 
    139 	(void)mp;
    140 	KASSERT(mp != NULL);
    141 	KASSERT(fdvp != NULL);
    142 	KASSERT(fvp != NULL);
    143 	KASSERT(tdvp != NULL);
    144 	KASSERT(fdvp != fvp);
    145 	KASSERT(fdvp != tvp);
    146 	KASSERT(tdvp != fvp);
    147 	KASSERT(tdvp != tvp);
    148 	KASSERT(fvp != tvp);
    149 	KASSERT(fdvp->v_type == VDIR);
    150 	KASSERT(tdvp->v_type == VDIR);
    151 	KASSERT(fdvp->v_mount == mp);
    152 	KASSERT(fvp->v_mount == mp);
    153 	KASSERT(tdvp->v_mount == mp);
    154 	KASSERT((tvp == NULL) || (tvp->v_mount == mp));
    155 	KASSERT(VOP_ISLOCKED(fdvp) == LK_EXCLUSIVE);
    156 	KASSERT(VOP_ISLOCKED(fvp) == LK_EXCLUSIVE);
    157 	KASSERT(VOP_ISLOCKED(tdvp) == LK_EXCLUSIVE);
    158 	KASSERT((tvp == NULL) || (VOP_ISLOCKED(tvp) == LK_EXCLUSIVE));
    159 
    160 	return genfs_ufslike_rename_check_possible(
    161 	    VP_TO_TMPFS_NODE(fdvp)->tn_flags, VP_TO_TMPFS_NODE(fvp)->tn_flags,
    162 	    VP_TO_TMPFS_NODE(tdvp)->tn_flags,
    163 	    (tvp? VP_TO_TMPFS_NODE(tvp)->tn_flags : 0), (tvp != NULL),
    164 	    IMMUTABLE, APPEND);
    165 }
    166 
    167 /*
    168  * tmpfs_gro_rename_check_permitted: Check whether a rename is
    169  * permitted given our credentials.
    170  */
    171 static int
    172 tmpfs_gro_rename_check_permitted(struct mount *mp, kauth_cred_t cred,
    173     struct vnode *fdvp, struct vnode *fvp,
    174     struct vnode *tdvp, struct vnode *tvp)
    175 {
    176 
    177 	(void)mp;
    178 	KASSERT(mp != NULL);
    179 	KASSERT(fdvp != NULL);
    180 	KASSERT(fvp != NULL);
    181 	KASSERT(tdvp != NULL);
    182 	KASSERT(fdvp != fvp);
    183 	KASSERT(fdvp != tvp);
    184 	KASSERT(tdvp != fvp);
    185 	KASSERT(tdvp != tvp);
    186 	KASSERT(fvp != tvp);
    187 	KASSERT(fdvp->v_type == VDIR);
    188 	KASSERT(tdvp->v_type == VDIR);
    189 	KASSERT(fdvp->v_mount == mp);
    190 	KASSERT(fvp->v_mount == mp);
    191 	KASSERT(tdvp->v_mount == mp);
    192 	KASSERT((tvp == NULL) || (tvp->v_mount == mp));
    193 	KASSERT(VOP_ISLOCKED(fdvp) == LK_EXCLUSIVE);
    194 	KASSERT(VOP_ISLOCKED(fvp) == LK_EXCLUSIVE);
    195 	KASSERT(VOP_ISLOCKED(tdvp) == LK_EXCLUSIVE);
    196 	KASSERT((tvp == NULL) || (VOP_ISLOCKED(tvp) == LK_EXCLUSIVE));
    197 
    198 	return genfs_ufslike_rename_check_permitted(cred,
    199 	    fdvp, VP_TO_TMPFS_NODE(fdvp)->tn_mode,
    200 	    VP_TO_TMPFS_NODE(fdvp)->tn_uid,
    201 	    fvp, VP_TO_TMPFS_NODE(fvp)->tn_uid,
    202 	    tdvp, VP_TO_TMPFS_NODE(tdvp)->tn_mode,
    203 	    VP_TO_TMPFS_NODE(tdvp)->tn_uid,
    204 	    tvp, (tvp? VP_TO_TMPFS_NODE(tvp)->tn_uid : 0));
    205 }
    206 
    207 /*
    208  * tmpfs_gro_remove_check_possible: Check whether a remove is possible
    209  * independent of credentials.
    210  */
    211 static int
    212 tmpfs_gro_remove_check_possible(struct mount *mp,
    213     struct vnode *dvp, struct vnode *vp)
    214 {
    215 
    216 	(void)mp;
    217 	KASSERT(mp != NULL);
    218 	KASSERT(dvp != NULL);
    219 	KASSERT(vp != NULL);
    220 	KASSERT(dvp != vp);
    221 	KASSERT(dvp->v_type == VDIR);
    222 	KASSERT(vp->v_type != VDIR);
    223 	KASSERT(dvp->v_mount == mp);
    224 	KASSERT(vp->v_mount == mp);
    225 	KASSERT(VOP_ISLOCKED(dvp) == LK_EXCLUSIVE);
    226 	KASSERT(VOP_ISLOCKED(vp) == LK_EXCLUSIVE);
    227 
    228 	return genfs_ufslike_remove_check_possible(
    229 	    VP_TO_TMPFS_NODE(dvp)->tn_flags, VP_TO_TMPFS_NODE(vp)->tn_flags,
    230 	    IMMUTABLE, APPEND);
    231 }
    232 
    233 /*
    234  * tmpfs_gro_remove_check_permitted: Check whether a remove is
    235  * permitted given our credentials.
    236  */
    237 static int
    238 tmpfs_gro_remove_check_permitted(struct mount *mp, kauth_cred_t cred,
    239     struct vnode *dvp, struct vnode *vp)
    240 {
    241 
    242 	(void)mp;
    243 	KASSERT(mp != NULL);
    244 	KASSERT(dvp != NULL);
    245 	KASSERT(vp != NULL);
    246 	KASSERT(dvp != vp);
    247 	KASSERT(dvp->v_type == VDIR);
    248 	KASSERT(vp->v_type != VDIR);
    249 	KASSERT(dvp->v_mount == mp);
    250 	KASSERT(vp->v_mount == mp);
    251 	KASSERT(VOP_ISLOCKED(dvp) == LK_EXCLUSIVE);
    252 	KASSERT(VOP_ISLOCKED(vp) == LK_EXCLUSIVE);
    253 
    254 	return genfs_ufslike_remove_check_permitted(cred,
    255 	    dvp, VP_TO_TMPFS_NODE(dvp)->tn_mode, VP_TO_TMPFS_NODE(dvp)->tn_uid,
    256 	    vp, VP_TO_TMPFS_NODE(vp)->tn_uid);
    257 }
    258 
    259 /*
    260  * tmpfs_gro_rename: Actually perform the rename operation.
    261  */
    262 static int
    263 tmpfs_gro_rename(struct mount *mp, kauth_cred_t cred,
    264     struct vnode *fdvp, struct componentname *fcnp,
    265     void *fde, struct vnode *fvp,
    266     struct vnode *tdvp, struct componentname *tcnp,
    267     void *tde, struct vnode *tvp, nlink_t *tvp_nlinkp)
    268 {
    269 	tmpfs_node_t *fdnode = VP_TO_TMPFS_DIR(fdvp);
    270 	tmpfs_node_t *tdnode = VP_TO_TMPFS_DIR(tdvp);
    271 	struct tmpfs_dirent **fdep = fde;
    272 	struct tmpfs_dirent **tdep = tde;
    273 	char *newname;
    274 
    275 	(void)cred;
    276 	KASSERT(mp != NULL);
    277 	KASSERT(fdvp != NULL);
    278 	KASSERT(fcnp != NULL);
    279 	KASSERT(fdep != NULL);
    280 	KASSERT(fvp != NULL);
    281 	KASSERT(tdvp != NULL);
    282 	KASSERT(tcnp != NULL);
    283 	KASSERT(tdep != NULL);
    284 	KASSERT(fdep != tdep);
    285 	KASSERT((tvp == NULL) || (*fdep) != (*tdep));
    286 	KASSERT((*fdep) != NULL);
    287 	KASSERT((*fdep)->td_node == VP_TO_TMPFS_NODE(fvp));
    288 	KASSERT((tvp == NULL) || ((*tdep) != NULL));
    289 	KASSERT((tvp == NULL) || ((*tdep)->td_node == VP_TO_TMPFS_NODE(tvp)));
    290 	KASSERT(fdvp != fvp);
    291 	KASSERT(fdvp != tvp);
    292 	KASSERT(tdvp != fvp);
    293 	KASSERT(tdvp != tvp);
    294 	KASSERT(fvp != tvp);
    295 	KASSERT(fdvp->v_mount == mp);
    296 	KASSERT(fvp->v_mount == mp);
    297 	KASSERT(tdvp->v_mount == mp);
    298 	KASSERT((tvp == NULL) || (tvp->v_mount == mp));
    299 	KASSERT(VOP_ISLOCKED(fdvp) == LK_EXCLUSIVE);
    300 	KASSERT(VOP_ISLOCKED(fvp) == LK_EXCLUSIVE);
    301 	KASSERT(VOP_ISLOCKED(tdvp) == LK_EXCLUSIVE);
    302 	KASSERT((tvp == NULL) || (VOP_ISLOCKED(tvp) == LK_EXCLUSIVE));
    303 
    304 	if (tmpfs_strname_neqlen(fcnp, tcnp)) {
    305 		newname = tmpfs_strname_alloc(VFS_TO_TMPFS(mp),
    306 		    tcnp->cn_namelen);
    307 		if (newname == NULL)
    308 			return ENOSPC;
    309 	} else {
    310 		newname = NULL;
    311 	}
    312 
    313 	/*
    314 	 * If we are moving from one directory to another, detach the
    315 	 * source entry and reattach it to the target directory.
    316 	 */
    317 	if (fdvp != tdvp) {
    318 		tmpfs_dir_detach(fdnode, *fdep);
    319 		tmpfs_dir_attach(tdnode, *fdep, VP_TO_TMPFS_NODE(fvp));
    320 	}
    321 
    322 	/*
    323 	 * If we are replacing an existing target entry, delete it.
    324 	 *
    325 	 * XXX What if the target is a directory with whiteout entries?
    326 	 */
    327 	if (tvp != NULL) {
    328 		tdnode = VP_TO_TMPFS_DIR(tdvp);
    329 
    330 		KASSERT((*tdep) != NULL);
    331 		KASSERT((*tdep)->td_node == VP_TO_TMPFS_NODE(tvp));
    332 		KASSERT((fvp->v_type == VDIR) == (tvp->v_type == VDIR));
    333 		if (tvp->v_type == VDIR) {
    334 			KASSERT(VP_TO_TMPFS_NODE(tvp)->tn_size == 0);
    335 			KASSERT(VP_TO_TMPFS_NODE(tvp)->tn_links == 2);
    336 
    337 			/*
    338 			 * Decrement the extra link count for `.' so
    339 			 * the vnode will be recycled when released.
    340 			 */
    341 			VP_TO_TMPFS_NODE(tvp)->tn_links--;
    342 		}
    343 		tmpfs_dir_detach(tdnode, *tdep);
    344 		tmpfs_free_dirent(VFS_TO_TMPFS(mp), *tdep);
    345 
    346 		*tvp_nlinkp = VP_TO_TMPFS_NODE(tvp)->tn_links;
    347 	}
    348 
    349 	/*
    350 	 * Update the directory entry's name if necessary, and flag
    351 	 * metadata updates.  A memory allocation failure here is not
    352 	 * OK because we've already committed some changes that we
    353 	 * can't back out at this point, hence the early allocation
    354 	 * above.
    355 	 */
    356 	if (newname != NULL) {
    357 		KASSERT(tcnp->cn_namelen <= TMPFS_MAXNAMLEN);
    358 
    359 		tmpfs_strname_free(VFS_TO_TMPFS(mp), (*fdep)->td_name,
    360 		    (*fdep)->td_namelen);
    361 		(*fdep)->td_namelen = (uint16_t)tcnp->cn_namelen;
    362 		(void)memcpy(newname, tcnp->cn_nameptr, tcnp->cn_namelen);
    363 		(*fdep)->td_name = newname;
    364 	}
    365 
    366 	/*
    367 	 * Update the timestamps of both parent directories and
    368 	 * the renamed file itself.
    369 	 */
    370 	tmpfs_update(fdvp, TMPFS_UPDATE_MTIME | TMPFS_UPDATE_CTIME);
    371 	tmpfs_update(tdvp, TMPFS_UPDATE_MTIME | TMPFS_UPDATE_CTIME);
    372 	tmpfs_update(fvp, TMPFS_UPDATE_CTIME);
    373 
    374 	genfs_rename_cache_purge(fdvp, fvp, tdvp, tvp);
    375 
    376 	return 0;
    377 }
    378 
    379 /*
    380  * tmpfs_gro_remove: Rename an object over another link to itself,
    381  * effectively removing just the original link.
    382  */
    383 static int
    384 tmpfs_gro_remove(struct mount *mp, kauth_cred_t cred,
    385     struct vnode *dvp, struct componentname *cnp, void *de, struct vnode *vp,
    386     nlink_t *tvp_nlinkp)
    387 {
    388 	tmpfs_node_t *dnode = VP_TO_TMPFS_DIR(dvp);
    389 	struct tmpfs_dirent **dep = de;
    390 
    391 	(void)vp;
    392 	KASSERT(mp != NULL);
    393 	KASSERT(dvp != NULL);
    394 	KASSERT(cnp != NULL);
    395 	KASSERT(dep != NULL);
    396 	KASSERT(vp != NULL);
    397 	KASSERT(dvp != vp);
    398 	KASSERT(dvp->v_mount == mp);
    399 	KASSERT(vp->v_mount == mp);
    400 	KASSERT(dvp->v_type == VDIR);
    401 	KASSERT(vp->v_type != VDIR);
    402 	KASSERT(VOP_ISLOCKED(dvp) == LK_EXCLUSIVE);
    403 	KASSERT(VOP_ISLOCKED(vp) == LK_EXCLUSIVE);
    404 
    405 	KASSERT((*dep)->td_node == VP_TO_TMPFS_NODE(vp));
    406 
    407 	tmpfs_dir_detach(dnode, *dep);
    408 	tmpfs_free_dirent(VFS_TO_TMPFS(mp), *dep);
    409 	tmpfs_update(dvp, TMPFS_UPDATE_MTIME | TMPFS_UPDATE_CTIME);
    410 
    411 	*tvp_nlinkp = VP_TO_TMPFS_NODE(vp)->tn_links;
    412 
    413 	return 0;
    414 }
    415 
    416 /*
    417  * tmpfs_gro_lookup: Look up and save the lookup results.
    418  */
    419 static int
    420 tmpfs_gro_lookup(struct mount *mp, struct vnode *dvp,
    421     struct componentname *cnp, void *de_ret, struct vnode **vp_ret)
    422 {
    423 	struct tmpfs_dirent *dirent, **dep_ret = de_ret;
    424 	struct vnode *vp;
    425 	int error;
    426 
    427 	(void)mp;
    428 	KASSERT(mp != NULL);
    429 	KASSERT(dvp != NULL);
    430 	KASSERT(cnp != NULL);
    431 	KASSERT(dep_ret != NULL);
    432 	KASSERT(vp_ret != NULL);
    433 	KASSERT(VOP_ISLOCKED(dvp) == LK_EXCLUSIVE);
    434 
    435 	dirent = tmpfs_dir_lookup(VP_TO_TMPFS_NODE(dvp), cnp);
    436 	if (dirent == NULL)
    437 		return ENOENT;
    438 
    439 	error = vcache_get(mp, &dirent->td_node, sizeof(dirent->td_node), &vp);
    440 	if (error)
    441 		return error;
    442 	KASSERT(vp != NULL);
    443 
    444 	*dep_ret = dirent;
    445 	*vp_ret = vp;
    446 	return 0;
    447 }
    448 
    449 /*
    450  * tmpfs_rmdired_p: Check whether the directory vp has been rmdired.
    451  *
    452  * vp must be locked and referenced.
    453  */
    454 static bool
    455 tmpfs_rmdired_p(struct vnode *vp)
    456 {
    457 
    458 	KASSERT(vp != NULL);
    459 	KASSERT(VOP_ISLOCKED(vp) == LK_EXCLUSIVE);
    460 	KASSERT(vp->v_type == VDIR);
    461 
    462 	return (VP_TO_TMPFS_NODE(vp)->tn_spec.tn_dir.tn_parent == NULL);
    463 }
    464 
    465 /*
    466  * tmpfs_gro_genealogy: Analyze the genealogy of the source and target
    467  * directories.
    468  */
    469 static int
    470 tmpfs_gro_genealogy(struct mount *mp, kauth_cred_t cred,
    471     struct vnode *fdvp, struct vnode *tdvp,
    472     struct vnode **intermediate_node_ret)
    473 {
    474 	struct vnode *vp, *ovp;
    475 	struct tmpfs_node *dnode;
    476 	int error;
    477 
    478 	(void)cred;
    479 	KASSERT(mp != NULL);
    480 	KASSERT(fdvp != NULL);
    481 	KASSERT(tdvp != NULL);
    482 	KASSERT(fdvp != tdvp);
    483 	KASSERT(intermediate_node_ret != NULL);
    484 	KASSERT(fdvp->v_mount == mp);
    485 	KASSERT(tdvp->v_mount == mp);
    486 	KASSERT(fdvp->v_type == VDIR);
    487 	KASSERT(tdvp->v_type == VDIR);
    488 
    489 	/*
    490 	 * We need to provisionally lock tdvp to keep rmdir from
    491 	 * deleting it -- or any ancestor -- at an inopportune moment.
    492 	 */
    493 	error = tmpfs_gro_lock_directory(mp, tdvp);
    494 	if (error)
    495 		return error;
    496 
    497 	vp = tdvp;
    498 	vref(vp);
    499 
    500 	for (;;) {
    501 		KASSERT(vp != NULL);
    502 		KASSERT(VOP_ISLOCKED(vp) == LK_EXCLUSIVE);
    503 		KASSERT(vp->v_mount == mp);
    504 		KASSERT(vp->v_type == VDIR);
    505 		KASSERT(!tmpfs_rmdired_p(vp));
    506 
    507 		dnode = VP_TO_TMPFS_NODE(vp)->tn_spec.tn_dir.tn_parent;
    508 
    509 		/*
    510 		 * If dnode is null then vp has been rmdir'd, which is
    511 		 * not supposed to happen because we have it locked.
    512 		 */
    513 		KASSERT(dnode != NULL);
    514 
    515 		/* Did we hit the root without finding fdvp?  */
    516 		if (dnode == VP_TO_TMPFS_NODE(vp)) {
    517 			vput(vp);
    518 			*intermediate_node_ret = NULL;
    519 			return 0;
    520 		}
    521 
    522 		/* Did we find that fdvp is an ancestor of tdvp? */
    523 		if (dnode == VP_TO_TMPFS_NODE(fdvp)) {
    524 			KASSERT(dnode->tn_vnode == fdvp);
    525 			/* Unlock vp, but keep it referenced.  */
    526 			VOP_UNLOCK(vp);
    527 			*intermediate_node_ret = vp;
    528 			return 0;
    529 		}
    530 
    531 		/* Neither -- keep ascending the family tree.  */
    532 		ovp = vp;
    533 		vp = NULL;
    534 		error = vcache_get(mp, &dnode, sizeof(dnode), &vp);
    535 		vput(ovp);
    536 		if (error)
    537 			return error;
    538 		error = vn_lock(vp, LK_EXCLUSIVE);
    539 		if (error) {
    540 			vrele(vp);
    541 			return error;
    542 		}
    543 
    544 		/*
    545 		 * vcache_get only guarantees that dnode will not
    546 		 * be freed while we get a vnode for it.  It does not
    547 		 * preserve any other invariants, so we must check
    548 		 * whether the parent has been removed in the meantime.
    549 		 */
    550 		if (tmpfs_rmdired_p(vp)) {
    551 			vput(vp);
    552 			return ENOENT;
    553 		}
    554 	}
    555 }
    556 
    557 /*
    558  * tmpfs_gro_lock_directory: Lock the directory vp, but fail if it has
    559  * been rmdir'd.
    560  */
    561 static int
    562 tmpfs_gro_lock_directory(struct mount *mp, struct vnode *vp)
    563 {
    564 
    565 	(void)mp;
    566 	KASSERT(mp != NULL);
    567 	KASSERT(vp != NULL);
    568 	KASSERT(vp->v_mount == mp);
    569 
    570 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
    571 
    572 	if (tmpfs_rmdired_p(vp)) {
    573 		VOP_UNLOCK(vp);
    574 		return ENOENT;
    575 	}
    576 
    577 	return 0;
    578 }
    579 
    580 static const struct genfs_rename_ops tmpfs_genfs_rename_ops = {
    581 	.gro_directory_empty_p		= tmpfs_gro_directory_empty_p,
    582 	.gro_rename_check_possible	= tmpfs_gro_rename_check_possible,
    583 	.gro_rename_check_permitted	= tmpfs_gro_rename_check_permitted,
    584 	.gro_remove_check_possible	= tmpfs_gro_remove_check_possible,
    585 	.gro_remove_check_permitted	= tmpfs_gro_remove_check_permitted,
    586 	.gro_rename			= tmpfs_gro_rename,
    587 	.gro_remove			= tmpfs_gro_remove,
    588 	.gro_lookup			= tmpfs_gro_lookup,
    589 	.gro_genealogy			= tmpfs_gro_genealogy,
    590 	.gro_lock_directory		= tmpfs_gro_lock_directory,
    591 };
    592