xref: /xnu-8792.61.2/bsd/vfs/vfs_init.c (revision 42e220869062b56f8d7d0726fd4c88954f87902c)
1 /*
2  * Copyright (c) 2000-2010 Apple Inc. All rights reserved.
3  *
4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5  *
6  * This file contains Original Code and/or Modifications of Original Code
7  * as defined in and that are subject to the Apple Public Source License
8  * Version 2.0 (the 'License'). You may not use this file except in
9  * compliance with the License. The rights granted to you under the License
10  * may not be used to create, or enable the creation or redistribution of,
11  * unlawful or unlicensed copies of an Apple operating system, or to
12  * circumvent, violate, or enable the circumvention or violation of, any
13  * terms of an Apple operating system software license agreement.
14  *
15  * Please obtain a copy of the License at
16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
17  *
18  * The Original Code and all software distributed under the License are
19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23  * Please see the License for the specific language governing rights and
24  * limitations under the License.
25  *
26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27  */
28 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
29 /*
30  * Copyright (c) 1989, 1993
31  *	The Regents of the University of California.  All rights reserved.
32  *
33  * This code is derived from software contributed
34  * to Berkeley by John Heidemann of the UCLA Ficus project.
35  *
36  * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
37  *
38  * Redistribution and use in source and binary forms, with or without
39  * modification, are permitted provided that the following conditions
40  * are met:
41  * 1. Redistributions of source code must retain the above copyright
42  *    notice, this list of conditions and the following disclaimer.
43  * 2. Redistributions in binary form must reproduce the above copyright
44  *    notice, this list of conditions and the following disclaimer in the
45  *    documentation and/or other materials provided with the distribution.
46  * 3. All advertising materials mentioning features or use of this software
47  *    must display the following acknowledgement:
48  *	This product includes software developed by the University of
49  *	California, Berkeley and its contributors.
50  * 4. Neither the name of the University nor the names of its contributors
51  *    may be used to endorse or promote products derived from this software
52  *    without specific prior written permission.
53  *
54  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
55  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
56  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
57  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
58  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
59  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
60  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
61  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
62  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
63  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
64  * SUCH DAMAGE.
65  *
66  *	@(#)vfs_init.c	8.5 (Berkeley) 5/11/95
67  */
68 /*
69  * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
70  * support for mandatory and extensible security protections.  This notice
71  * is included in support of clause 2.2 (b) of the Apple Public License,
72  * Version 2.0.
73  */
74 
75 
76 #include <sys/param.h>
77 #include <sys/mount_internal.h>
78 #include <sys/time.h>
79 #include <sys/vm.h>
80 #include <sys/vnode_internal.h>
81 #include <sys/stat.h>
82 #include <sys/namei.h>
83 #include <sys/ucred.h>
84 #include <sys/errno.h>
85 #include <kern/kalloc.h>
86 #include <sys/decmpfs.h>
87 
88 #if CONFIG_MACF
89 #include <security/mac_framework.h>
90 #include <sys/kauth.h>
91 #endif
92 #if QUOTA
93 #include <sys/quota.h>
94 #endif
95 
96 /*
97  * Sigh, such primitive tools are these...
98  */
99 #if 0
100 #define DODEBUG(A) A
101 #else
102 #define DODEBUG(A)
103 #endif
104 
105 ZONE_DEFINE_TYPE(mount_zone, "mount", struct mount, ZC_ZFREE_CLEARMEM);
106 
107 __private_extern__ void vntblinit(void);
108 
109 extern const struct vnodeopv_desc *vfs_opv_descs[];
110 /* a list of lists of vnodeops defns */
111 extern struct vnodeop_desc *vfs_op_descs[];
112 /* and the operations they perform */
113 /*
114  * This code doesn't work if the defn is **vnodop_defns with cc.
115  * The problem is because of the compiler sometimes putting in an
116  * extra level of indirection for arrays.  It's an interesting
117  * "feature" of C.
118  */
119 int vfs_opv_numops;
120 
121 typedef int (*PFIvp)(void *);
122 
123 /*
124  * A miscellaneous routine.
125  * A generic "default" routine that just returns an error.
126  */
127 int
vn_default_error(void)128 vn_default_error(void)
129 {
130 	return ENOTSUP;
131 }
132 
133 /*
134  * vfs_init.c
135  *
136  * Allocate and fill in operations vectors.
137  *
138  * An undocumented feature of this approach to defining operations is that
139  * there can be multiple entries in vfs_opv_descs for the same operations
140  * vector. This allows third parties to extend the set of operations
141  * supported by another layer in a binary compatibile way. For example,
142  * assume that NFS needed to be modified to support Ficus. NFS has an entry
143  * (probably nfs_vnopdeop_decls) declaring all the operations NFS supports by
144  * default. Ficus could add another entry (ficus_nfs_vnodeop_decl_entensions)
145  * listing those new operations Ficus adds to NFS, all without modifying the
146  * NFS code. (Of couse, the OTW NFS protocol still needs to be munged, but
147  * that is a(whole)nother story.) This is a feature.
148  */
149 void
vfs_opv_init(void)150 vfs_opv_init(void)
151 {
152 	int i, j, k;
153 	int(***opv_desc_vector_p)(void *);
154 	int(**opv_desc_vector)(void *);
155 	const struct vnodeopv_entry_desc *opve_descp;
156 
157 	/*
158 	 * Allocate the dynamic vectors and fill them in.
159 	 */
160 	for (i = 0; vfs_opv_descs[i]; i++) {
161 		opv_desc_vector_p = vfs_opv_descs[i]->opv_desc_vector_p;
162 		/*
163 		 * Allocate and init the vector, if it needs it.
164 		 * Also handle backwards compatibility.
165 		 */
166 		if (*opv_desc_vector_p == NULL) {
167 			*opv_desc_vector_p = zalloc_permanent(vfs_opv_numops * sizeof(PFIvp),
168 			    ZALIGN(PFIvp));
169 			DODEBUG(printf("vector at %x allocated\n",
170 			    opv_desc_vector_p));
171 		}
172 		opv_desc_vector = *opv_desc_vector_p;
173 		for (j = 0; vfs_opv_descs[i]->opv_desc_ops[j].opve_op; j++) {
174 			opve_descp = &(vfs_opv_descs[i]->opv_desc_ops[j]);
175 
176 			/* Silently skip known-disabled operations */
177 			if (opve_descp->opve_op->vdesc_flags & VDESC_DISABLED) {
178 				printf("vfs_fsadd: Ignoring reference in %p to disabled operation %s.\n",
179 				    vfs_opv_descs[i], opve_descp->opve_op->vdesc_name);
180 				continue;
181 			}
182 
183 			/*
184 			 * Sanity check:  is this operation listed
185 			 * in the list of operations?  We check this
186 			 * by seeing if its offest is zero.  Since
187 			 * the default routine should always be listed
188 			 * first, it should be the only one with a zero
189 			 * offset.  Any other operation with a zero
190 			 * offset is probably not listed in
191 			 * vfs_op_descs, and so is probably an error.
192 			 *
193 			 * A panic here means the layer programmer
194 			 * has committed the all-too common bug
195 			 * of adding a new operation to the layer's
196 			 * list of vnode operations but
197 			 * not adding the operation to the system-wide
198 			 * list of supported operations.
199 			 */
200 			if (opve_descp->opve_op->vdesc_offset == 0 &&
201 			    opve_descp->opve_op !=
202 			    VDESC(vnop_default)) {
203 				printf("operation %s not listed in %s.\n",
204 				    opve_descp->opve_op->vdesc_name,
205 				    "vfs_op_descs");
206 				panic("vfs_opv_init: bad operation");
207 			}
208 			/*
209 			 * Fill in this entry.
210 			 */
211 			opv_desc_vector[opve_descp->opve_op->vdesc_offset] =
212 			    opve_descp->opve_impl;
213 		}
214 	}
215 	/*
216 	 * Finally, go back and replace unfilled routines
217 	 * with their default.  (Sigh, an O(n^3) algorithm.  I
218 	 * could make it better, but that'd be work, and n is small.)
219 	 */
220 	for (i = 0; vfs_opv_descs[i]; i++) {
221 		opv_desc_vector = *(vfs_opv_descs[i]->opv_desc_vector_p);
222 		/*
223 		 * Force every operations vector to have a default routine.
224 		 */
225 		if (opv_desc_vector[VOFFSET(vnop_default)] == NULL) {
226 			panic("vfs_opv_init: operation vector without default routine.");
227 		}
228 		for (k = 0; k < vfs_opv_numops; k++) {
229 			if (opv_desc_vector[k] == NULL) {
230 				opv_desc_vector[k] =
231 				    opv_desc_vector[VOFFSET(vnop_default)];
232 			}
233 		}
234 	}
235 }
236 
237 /*
238  * Initialize known vnode operations vectors.
239  */
240 void
vfs_op_init(void)241 vfs_op_init(void)
242 {
243 	int i;
244 
245 	DODEBUG(printf("Vnode_interface_init.\n"));
246 	/*
247 	 * Set all vnode vectors to a well known value.
248 	 */
249 	for (i = 0; vfs_opv_descs[i]; i++) {
250 		*(vfs_opv_descs[i]->opv_desc_vector_p) = NULL;
251 	}
252 	/*
253 	 * Figure out how many ops there are by counting the table,
254 	 * and assign each its offset.
255 	 */
256 	for (vfs_opv_numops = 0, i = 0; vfs_op_descs[i]; i++) {
257 		/* Silently skip known-disabled operations */
258 		if (vfs_op_descs[i]->vdesc_flags & VDESC_DISABLED) {
259 			continue;
260 		}
261 		vfs_op_descs[i]->vdesc_offset = vfs_opv_numops;
262 		vfs_opv_numops++;
263 	}
264 	DODEBUG(printf("vfs_opv_numops=%d\n", vfs_opv_numops));
265 }
266 
267 /*
268  * Routines having to do with the management of the vnode table.
269  */
270 extern struct vnodeops dead_vnodeops;
271 extern struct vnodeops spec_vnodeops;
272 
273 /* vars for vnode list lock */
274 static LCK_GRP_DECLARE(vnode_list_lck_grp, "vnode list");
275 static LCK_ATTR_DECLARE(vnode_list_lck_attr, 0, 0);
276 static LCK_SPIN_DECLARE_ATTR(vnode_list_spin_lock,
277     &vnode_list_lck_grp, &vnode_list_lck_attr);
278 static LCK_MTX_DECLARE_ATTR(spechash_mtx_lock,
279     &vnode_list_lck_grp, &vnode_list_lck_attr);
280 LCK_MTX_DECLARE_ATTR(pkg_extensions_lck,
281     &vnode_list_lck_grp, &vnode_list_lck_attr);
282 
283 /* vars for mount lock */
284 static LCK_GRP_DECLARE(mnt_lck_grp, "mount");
285 static LCK_ATTR_DECLARE(mnt_lck_attr, 0, 0);
286 
287 /* vars for mount list lock */
288 static LCK_GRP_DECLARE(mnt_list_lck_grp, "mount list");
289 LCK_MTX_DECLARE(mnt_list_mtx_lock, &mnt_list_lck_grp);
290 
291 /*
292  * We want dead_mountp to be a constant pointer, but vfsinit() runs
293  * pretty late, so we'll allocate the dead_mount statically and
294  * statically-initialized dead_mountp.
295  */
296 static struct mount dead_mount_store;
297 struct mount * const dead_mountp = &dead_mount_store;
298 
299 /*
300  * Initialize the vnode structures and initialize each file system type.
301  */
302 void
vfsinit(void)303 vfsinit(void)
304 {
305 	struct vfstable *vfsp;
306 	int i, maxtypenum;
307 	struct mount * mp;
308 
309 	/*
310 	 * Initialize the vnode table
311 	 */
312 	vntblinit();
313 	/*
314 	 * Initialize the filesystem event mechanism.
315 	 */
316 	vfs_event_init();
317 	/*
318 	 * Initialize the vnode name cache
319 	 */
320 	nchinit();
321 
322 	/*
323 	 * Build vnode operation vectors.
324 	 */
325 	vfs_op_init();
326 	vfs_opv_init();   /* finish the job */
327 	/*
328 	 * Initialize each file system type in the static list,
329 	 * until the first NULL ->vfs_vfsops is encountered.
330 	 */
331 	maxtypenum = VT_NON;
332 	for (vfsp = vfsconf, i = 0; i < maxvfsslots; i++, vfsp++) {
333 		struct vfsconf vfsc;
334 		if (vfsp->vfc_vfsops == (struct vfsops *)0) {
335 			break;
336 		}
337 		if (i) {
338 			vfsconf[i - 1].vfc_next = vfsp;
339 		}
340 		if (maxtypenum <= vfsp->vfc_typenum) {
341 			maxtypenum = vfsp->vfc_typenum + 1;
342 		}
343 
344 		bzero(&vfsc, sizeof(struct vfsconf));
345 		vfsc.vfc_reserved1 = 0;
346 		bcopy(vfsp->vfc_name, vfsc.vfc_name, sizeof(vfsc.vfc_name));
347 		vfsc.vfc_typenum = vfsp->vfc_typenum;
348 		vfsc.vfc_refcount = vfsp->vfc_refcount;
349 		vfsc.vfc_flags = vfsp->vfc_flags;
350 		vfsc.vfc_reserved2 = 0;
351 		vfsc.vfc_reserved3 = 0;
352 
353 		if (vfsp->vfc_vfsops->vfs_sysctl) {
354 			struct sysctl_oid *oidp = NULL;
355 			struct sysctl_oid oid = SYSCTL_STRUCT_INIT(_vfs, vfsp->vfc_typenum, , CTLTYPE_NODE | CTLFLAG_KERN | CTLFLAG_RW | CTLFLAG_LOCKED, NULL, 0, vfs_sysctl_node, "-", "");
356 
357 			oidp = kalloc_type(struct sysctl_oid, Z_WAITOK);
358 			*oidp = oid;
359 
360 			/* Memory for VFS oid held by vfsentry forever */
361 			vfsp->vfc_sysctl = oidp;
362 			oidp->oid_name = vfsp->vfc_name;
363 			sysctl_register_oid(vfsp->vfc_sysctl);
364 		}
365 
366 		(*vfsp->vfc_vfsops->vfs_init)(&vfsc);
367 
368 		numused_vfsslots++;
369 		numregistered_fses++;
370 	}
371 	/* next vfc_typenum to be used */
372 	maxvfstypenum = maxtypenum;
373 
374 	/*
375 	 * Initialize the vnop authorization scope.
376 	 */
377 	vnode_authorize_init();
378 
379 	/*
380 	 * create a mount point for dead vnodes
381 	 */
382 	mp = &dead_mount_store;
383 	/* Initialize the default IO constraints */
384 	mp->mnt_maxreadcnt = mp->mnt_maxwritecnt = MAXPHYS;
385 	mp->mnt_segreadcnt = mp->mnt_segwritecnt = 32;
386 	mp->mnt_maxsegreadsize = mp->mnt_maxreadcnt;
387 	mp->mnt_maxsegwritesize = mp->mnt_maxwritecnt;
388 	mp->mnt_devblocksize = DEV_BSIZE;
389 	mp->mnt_alignmentmask = PAGE_MASK;
390 	mp->mnt_ioqueue_depth = MNT_DEFAULT_IOQUEUE_DEPTH;
391 	mp->mnt_ioscale = 1;
392 	mp->mnt_ioflags = 0;
393 	mp->mnt_realrootvp = NULLVP;
394 	mp->mnt_authcache_ttl = CACHED_LOOKUP_RIGHT_TTL;
395 
396 	TAILQ_INIT(&mp->mnt_vnodelist);
397 	TAILQ_INIT(&mp->mnt_workerqueue);
398 	TAILQ_INIT(&mp->mnt_newvnodes);
399 	mp->mnt_flag = MNT_LOCAL;
400 	mp->mnt_lflag = MNT_LDEAD;
401 	mount_lock_init(mp);
402 
403 #if CONFIG_MACF
404 	mac_mount_label_init(mp);
405 	mac_mount_label_associate(vfs_context_kernel(), mp);
406 #endif
407 	/*
408 	 * dead_mountp is a statically-initialized constant pointer
409 	 * to dead_mount_store.
410 	 */
411 
412 #if FS_COMPRESSION
413 	decmpfs_init();
414 #endif
415 
416 	nspace_resolver_init();
417 }
418 
419 void
vnode_list_lock(void)420 vnode_list_lock(void)
421 {
422 	lck_spin_lock_grp(&vnode_list_spin_lock, &vnode_list_lck_grp);
423 }
424 
425 void
vnode_list_unlock(void)426 vnode_list_unlock(void)
427 {
428 	lck_spin_unlock(&vnode_list_spin_lock);
429 }
430 
431 void
mount_list_lock(void)432 mount_list_lock(void)
433 {
434 	lck_mtx_lock(&mnt_list_mtx_lock);
435 }
436 
437 void
mount_list_unlock(void)438 mount_list_unlock(void)
439 {
440 	lck_mtx_unlock(&mnt_list_mtx_lock);
441 }
442 
443 void
mount_lock_init(mount_t mp)444 mount_lock_init(mount_t mp)
445 {
446 	lck_mtx_init(&mp->mnt_mlock, &mnt_lck_grp, &mnt_lck_attr);
447 	lck_mtx_init(&mp->mnt_iter_lock, &mnt_lck_grp, &mnt_lck_attr);
448 	lck_mtx_init(&mp->mnt_renamelock, &mnt_lck_grp, &mnt_lck_attr);
449 	lck_rw_init(&mp->mnt_rwlock, &mnt_lck_grp, &mnt_lck_attr);
450 }
451 
452 void
mount_lock_destroy(mount_t mp)453 mount_lock_destroy(mount_t mp)
454 {
455 	lck_mtx_destroy(&mp->mnt_mlock, &mnt_lck_grp);
456 	lck_mtx_destroy(&mp->mnt_iter_lock, &mnt_lck_grp);
457 	lck_mtx_destroy(&mp->mnt_renamelock, &mnt_lck_grp);
458 	lck_rw_destroy(&mp->mnt_rwlock, &mnt_lck_grp);
459 }
460 
461 
462 /*
463  * Name:	vfstable_add
464  *
465  * Description:	Add a filesystem to the vfsconf list at the first
466  *		unused slot.  If no slots are available, return an
467  *		error.
468  *
469  * Parameter:	nvfsp		vfsconf for VFS to add
470  *
471  * Returns:	0		Success
472  *		-1		Failure
473  *
474  * Notes:	The vfsconf should be treated as a linked list by
475  *		all external references, as the implementation is
476  *		expected to change in the future.  The linkage is
477  *		through ->vfc_next, and the list is NULL terminated.
478  *
479  * Warning:	This code assumes that vfsconf[0] is non-empty.
480  */
481 struct vfstable *
vfstable_add(struct vfstable * nvfsp)482 vfstable_add(struct vfstable  *nvfsp)
483 {
484 	int slot;
485 	struct vfstable *slotp, *allocated = NULL;
486 	struct sysctl_oid *oidp = NULL;
487 
488 
489 	if (nvfsp->vfc_vfsops->vfs_sysctl) {
490 		struct sysctl_oid oid = SYSCTL_STRUCT_INIT(_vfs, nvfsp->vfc_typenum, , CTLTYPE_NODE | CTLFLAG_KERN | CTLFLAG_RW | CTLFLAG_LOCKED, NULL, 0, vfs_sysctl_node, "-", "");
491 
492 		oidp = kalloc_type(struct sysctl_oid, Z_WAITOK);
493 		*oidp = oid;
494 	}
495 
496 	/*
497 	 * Find the next empty slot; we recognize an empty slot by a
498 	 * NULL-valued ->vfc_vfsops, so if we delete a VFS, we must
499 	 * ensure we set the entry back to NULL.
500 	 */
501 findslot:
502 	mount_list_lock();
503 	for (slot = 0; slot < maxvfsslots; slot++) {
504 		if (vfsconf[slot].vfc_vfsops == NULL) {
505 			break;
506 		}
507 	}
508 	if (slot == maxvfsslots) {
509 		if (allocated == NULL) {
510 			mount_list_unlock();
511 			/* out of static slots; allocate one instead */
512 			allocated = kalloc_type(struct vfstable, Z_WAITOK);
513 			goto findslot;
514 		} else {
515 			slotp = allocated;
516 		}
517 	} else {
518 		slotp = &vfsconf[slot];
519 	}
520 
521 	/*
522 	 * Replace the contents of the next empty slot with the contents
523 	 * of the provided nvfsp.
524 	 *
525 	 * Note; Takes advantage of the fact that 'slot' was left
526 	 * with the value of 'maxvfslots' in the allocation case.
527 	 */
528 	bcopy(nvfsp, slotp, sizeof(struct vfstable));
529 	if (slot != 0) {
530 		slotp->vfc_next = vfsconf[slot - 1].vfc_next;
531 		vfsconf[slot - 1].vfc_next = slotp;
532 	} else {
533 		slotp->vfc_next = NULL;
534 	}
535 
536 	if (slotp != allocated) {
537 		/* used a statically allocated slot */
538 		numused_vfsslots++;
539 	}
540 	numregistered_fses++;
541 
542 	if (oidp) {
543 		/* Memory freed in vfstable_del after unregistration */
544 		slotp->vfc_sysctl = oidp;
545 		oidp->oid_name = slotp->vfc_name;
546 		sysctl_register_oid(slotp->vfc_sysctl);
547 	}
548 
549 	mount_list_unlock();
550 
551 	if (allocated && allocated != slotp) {
552 		/* did allocation, but ended up using static slot */
553 		kfree_type(struct vfstable, allocated);
554 	}
555 
556 	return slotp;
557 }
558 
559 /*
560  * Name:	vfstable_del
561  *
562  * Description:	Remove a filesystem from the vfsconf list by name.
563  *		If no such filesystem exists, return an error.
564  *
565  * Parameter:	fs_name		name of VFS to remove
566  *
567  * Returns:	0		Success
568  *		-1		Failure
569  *
570  * Notes:	Hopefully all filesystems have unique names.
571  */
572 int
vfstable_del(struct vfstable * vtbl)573 vfstable_del(struct vfstable  * vtbl)
574 {
575 	struct vfstable **vcpp;
576 	struct vfstable *vcdelp;
577 
578 #if DEBUG
579 	lck_mtx_assert(&mnt_list_mtx_lock, LCK_MTX_ASSERT_OWNED);
580 #endif /* DEBUG */
581 
582 	/*
583 	 * Traverse the list looking for vtbl; if found, *vcpp
584 	 * will contain the address of the pointer to the entry to
585 	 * be removed.
586 	 */
587 	for (vcpp = &vfsconf; *vcpp; vcpp = &(*vcpp)->vfc_next) {
588 		if (*vcpp == vtbl) {
589 			break;
590 		}
591 	}
592 
593 	if (*vcpp == NULL) {
594 		return ESRCH; /* vtbl not on vfsconf list */
595 	}
596 	if ((*vcpp)->vfc_sysctl) {
597 		sysctl_unregister_oid((*vcpp)->vfc_sysctl);
598 		(*vcpp)->vfc_sysctl->oid_name = NULL;
599 		kfree_type(struct sysctl_oid, (*vcpp)->vfc_sysctl);
600 	}
601 
602 	/* Unlink entry */
603 	vcdelp = *vcpp;
604 	*vcpp = (*vcpp)->vfc_next;
605 
606 	/*
607 	 * Is this an entry from our static table?  We find out by
608 	 * seeing if the pointer to the object to be deleted places
609 	 * the object in the address space containing the table (or not).
610 	 */
611 	if (vcdelp >= vfsconf && vcdelp < (vfsconf + maxvfsslots)) {    /* Y */
612 		/* Mark as empty for vfscon_add() */
613 		bzero(vcdelp, sizeof(struct vfstable));
614 		numregistered_fses--;
615 		numused_vfsslots--;
616 	} else {                                                        /* N */
617 		/*
618 		 * This entry was dynamically allocated; we must free it;
619 		 * we would prefer to have just linked the caller's
620 		 * vfsconf onto our list, but it may not be persistent
621 		 * because of the previous (copying) implementation.
622 		 */
623 		numregistered_fses--;
624 		mount_list_unlock();
625 		kfree_type(struct vfstable, vcdelp);
626 		mount_list_lock();
627 	}
628 
629 #if DEBUG
630 	lck_mtx_assert(&mnt_list_mtx_lock, LCK_MTX_ASSERT_OWNED);
631 #endif /* DEBUG */
632 
633 	return 0;
634 }
635 
636 void
SPECHASH_LOCK(void)637 SPECHASH_LOCK(void)
638 {
639 	lck_mtx_lock(&spechash_mtx_lock);
640 }
641 
642 void
SPECHASH_UNLOCK(void)643 SPECHASH_UNLOCK(void)
644 {
645 	lck_mtx_unlock(&spechash_mtx_lock);
646 }
647