xref: /freebsd/sys/kern/vfs_default.c (revision 4d846d26)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed
8  * to Berkeley by John Heidemann of the UCLA Ficus project.
9  *
10  * Source: * @(#)i405_init.c 2.10 92/04/27 UCLA Ficus project
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include <sys/param.h>
41 #include <sys/systm.h>
42 #include <sys/bio.h>
43 #include <sys/buf.h>
44 #include <sys/conf.h>
45 #include <sys/event.h>
46 #include <sys/filio.h>
47 #include <sys/kernel.h>
48 #include <sys/limits.h>
49 #include <sys/lock.h>
50 #include <sys/lockf.h>
51 #include <sys/malloc.h>
52 #include <sys/mount.h>
53 #include <sys/namei.h>
54 #include <sys/rwlock.h>
55 #include <sys/fcntl.h>
56 #include <sys/unistd.h>
57 #include <sys/vnode.h>
58 #include <sys/dirent.h>
59 #include <sys/poll.h>
60 #include <sys/stat.h>
61 #include <security/audit/audit.h>
62 #include <sys/priv.h>
63 
64 #include <security/mac/mac_framework.h>
65 
66 #include <vm/vm.h>
67 #include <vm/vm_object.h>
68 #include <vm/vm_extern.h>
69 #include <vm/pmap.h>
70 #include <vm/vm_map.h>
71 #include <vm/vm_page.h>
72 #include <vm/vm_pager.h>
73 #include <vm/vnode_pager.h>
74 
75 static int	vop_nolookup(struct vop_lookup_args *);
76 static int	vop_norename(struct vop_rename_args *);
77 static int	vop_nostrategy(struct vop_strategy_args *);
78 static int	dirent_exists(struct vnode *vp, const char *dirname,
79 			      struct thread *td);
80 
81 static int vop_stdis_text(struct vop_is_text_args *ap);
82 static int vop_stdunset_text(struct vop_unset_text_args *ap);
83 static int vop_stdadd_writecount(struct vop_add_writecount_args *ap);
84 static int vop_stdcopy_file_range(struct vop_copy_file_range_args *ap);
85 static int vop_stdfdatasync(struct vop_fdatasync_args *ap);
86 static int vop_stdgetpages_async(struct vop_getpages_async_args *ap);
87 static int vop_stdread_pgcache(struct vop_read_pgcache_args *ap);
88 static int vop_stdstat(struct vop_stat_args *ap);
89 static int vop_stdvput_pair(struct vop_vput_pair_args *ap);
90 
91 /*
92  * This vnode table stores what we want to do if the filesystem doesn't
93  * implement a particular VOP.
94  *
95  * If there is no specific entry here, we will return EOPNOTSUPP.
96  *
97  * Note that every filesystem has to implement either vop_access
98  * or vop_accessx; failing to do so will result in immediate crash
99  * due to stack overflow, as vop_stdaccess() calls vop_stdaccessx(),
100  * which calls vop_stdaccess() etc.
101  */
102 
103 struct vop_vector default_vnodeops = {
104 	.vop_default =		NULL,
105 	.vop_bypass =		VOP_EOPNOTSUPP,
106 
107 	.vop_access =		vop_stdaccess,
108 	.vop_accessx =		vop_stdaccessx,
109 	.vop_advise =		vop_stdadvise,
110 	.vop_advlock =		vop_stdadvlock,
111 	.vop_advlockasync =	vop_stdadvlockasync,
112 	.vop_advlockpurge =	vop_stdadvlockpurge,
113 	.vop_allocate =		vop_stdallocate,
114 	.vop_deallocate =	vop_stddeallocate,
115 	.vop_bmap =		vop_stdbmap,
116 	.vop_close =		VOP_NULL,
117 	.vop_fsync =		VOP_NULL,
118 	.vop_stat =		vop_stdstat,
119 	.vop_fdatasync =	vop_stdfdatasync,
120 	.vop_getpages =		vop_stdgetpages,
121 	.vop_getpages_async =	vop_stdgetpages_async,
122 	.vop_getwritemount = 	vop_stdgetwritemount,
123 	.vop_inactive =		VOP_NULL,
124 	.vop_need_inactive =	vop_stdneed_inactive,
125 	.vop_ioctl =		vop_stdioctl,
126 	.vop_kqfilter =		vop_stdkqfilter,
127 	.vop_islocked =		vop_stdislocked,
128 	.vop_lock1 =		vop_stdlock,
129 	.vop_lookup =		vop_nolookup,
130 	.vop_open =		VOP_NULL,
131 	.vop_pathconf =		VOP_EINVAL,
132 	.vop_poll =		vop_nopoll,
133 	.vop_putpages =		vop_stdputpages,
134 	.vop_readlink =		VOP_EINVAL,
135 	.vop_read_pgcache =	vop_stdread_pgcache,
136 	.vop_rename =		vop_norename,
137 	.vop_revoke =		VOP_PANIC,
138 	.vop_strategy =		vop_nostrategy,
139 	.vop_unlock =		vop_stdunlock,
140 	.vop_vptocnp =		vop_stdvptocnp,
141 	.vop_vptofh =		vop_stdvptofh,
142 	.vop_unp_bind =		vop_stdunp_bind,
143 	.vop_unp_connect =	vop_stdunp_connect,
144 	.vop_unp_detach =	vop_stdunp_detach,
145 	.vop_is_text =		vop_stdis_text,
146 	.vop_set_text =		vop_stdset_text,
147 	.vop_unset_text =	vop_stdunset_text,
148 	.vop_add_writecount =	vop_stdadd_writecount,
149 	.vop_copy_file_range =	vop_stdcopy_file_range,
150 	.vop_vput_pair =	vop_stdvput_pair,
151 };
152 VFS_VOP_VECTOR_REGISTER(default_vnodeops);
153 
154 /*
155  * Series of placeholder functions for various error returns for
156  * VOPs.
157  */
158 
159 int
160 vop_eopnotsupp(struct vop_generic_args *ap)
161 {
162 	/*
163 	printf("vop_notsupp[%s]\n", ap->a_desc->vdesc_name);
164 	*/
165 
166 	return (EOPNOTSUPP);
167 }
168 
169 int
170 vop_ebadf(struct vop_generic_args *ap)
171 {
172 
173 	return (EBADF);
174 }
175 
176 int
177 vop_enotty(struct vop_generic_args *ap)
178 {
179 
180 	return (ENOTTY);
181 }
182 
183 int
184 vop_einval(struct vop_generic_args *ap)
185 {
186 
187 	return (EINVAL);
188 }
189 
190 int
191 vop_enoent(struct vop_generic_args *ap)
192 {
193 
194 	return (ENOENT);
195 }
196 
197 int
198 vop_eagain(struct vop_generic_args *ap)
199 {
200 
201 	return (EAGAIN);
202 }
203 
204 int
205 vop_null(struct vop_generic_args *ap)
206 {
207 
208 	return (0);
209 }
210 
211 /*
212  * Helper function to panic on some bad VOPs in some filesystems.
213  */
214 int
215 vop_panic(struct vop_generic_args *ap)
216 {
217 
218 	panic("filesystem goof: vop_panic[%s]", ap->a_desc->vdesc_name);
219 }
220 
221 /*
222  * vop_std<something> and vop_no<something> are default functions for use by
223  * filesystems that need the "default reasonable" implementation for a
224  * particular operation.
225  *
226  * The documentation for the operations they implement exists (if it exists)
227  * in the VOP_<SOMETHING>(9) manpage (all uppercase).
228  */
229 
230 /*
231  * Default vop for filesystems that do not support name lookup
232  */
233 static int
234 vop_nolookup(struct vop_lookup_args *ap)
235 {
236 
237 	*ap->a_vpp = NULL;
238 	return (ENOTDIR);
239 }
240 
241 /*
242  * vop_norename:
243  *
244  * Handle unlock and reference counting for arguments of vop_rename
245  * for filesystems that do not implement rename operation.
246  */
247 static int
248 vop_norename(struct vop_rename_args *ap)
249 {
250 
251 	vop_rename_fail(ap);
252 	return (EOPNOTSUPP);
253 }
254 
255 /*
256  *	vop_nostrategy:
257  *
258  *	Strategy routine for VFS devices that have none.
259  *
260  *	BIO_ERROR and B_INVAL must be cleared prior to calling any strategy
261  *	routine.  Typically this is done for a BIO_READ strategy call.
262  *	Typically B_INVAL is assumed to already be clear prior to a write
263  *	and should not be cleared manually unless you just made the buffer
264  *	invalid.  BIO_ERROR should be cleared either way.
265  */
266 
267 static int
268 vop_nostrategy (struct vop_strategy_args *ap)
269 {
270 	printf("No strategy for buffer at %p\n", ap->a_bp);
271 	vn_printf(ap->a_vp, "vnode ");
272 	ap->a_bp->b_ioflags |= BIO_ERROR;
273 	ap->a_bp->b_error = EOPNOTSUPP;
274 	bufdone(ap->a_bp);
275 	return (EOPNOTSUPP);
276 }
277 
278 /*
279  * Check if a named file exists in a given directory vnode
280  *
281  * Returns 0 if the file exists, ENOENT if it doesn't, or errors returned by
282  * vn_dir_next_dirent().
283  */
284 static int
285 dirent_exists(struct vnode *vp, const char *dirname, struct thread *td)
286 {
287 	char *dirbuf;
288 	int error, eofflag;
289 	size_t dirbuflen, len;
290 	off_t off;
291 	struct dirent *dp;
292 	struct vattr va;
293 
294 	ASSERT_VOP_LOCKED(vp, "vnode not locked");
295 	KASSERT(vp->v_type == VDIR, ("vp %p is not a directory", vp));
296 
297 	error = VOP_GETATTR(vp, &va, td->td_ucred);
298 	if (error != 0)
299 		return (error);
300 
301 	dirbuflen = MAX(DEV_BSIZE, GENERIC_MAXDIRSIZ);
302 	if (dirbuflen < va.va_blocksize)
303 		dirbuflen = va.va_blocksize;
304 	dirbuf = malloc(dirbuflen, M_TEMP, M_WAITOK);
305 
306 	len = 0;
307 	off = 0;
308 	eofflag = 0;
309 
310 	for (;;) {
311 		error = vn_dir_next_dirent(vp, td, dirbuf, dirbuflen,
312 		    &dp, &len, &off, &eofflag);
313 		if (error != 0)
314 			goto out;
315 
316 		if (len == 0)
317 			break;
318 
319 		if (dp->d_type != DT_WHT && dp->d_fileno != 0 &&
320 		    strcmp(dp->d_name, dirname) == 0)
321 			goto out;
322 	}
323 
324 	error = ENOENT;
325 
326 out:
327 	free(dirbuf, M_TEMP);
328 	return (error);
329 }
330 
331 int
332 vop_stdaccess(struct vop_access_args *ap)
333 {
334 
335 	KASSERT((ap->a_accmode & ~(VEXEC | VWRITE | VREAD | VADMIN |
336 	    VAPPEND)) == 0, ("invalid bit in accmode"));
337 
338 	return (VOP_ACCESSX(ap->a_vp, ap->a_accmode, ap->a_cred, ap->a_td));
339 }
340 
341 int
342 vop_stdaccessx(struct vop_accessx_args *ap)
343 {
344 	int error;
345 	accmode_t accmode = ap->a_accmode;
346 
347 	error = vfs_unixify_accmode(&accmode);
348 	if (error != 0)
349 		return (error);
350 
351 	if (accmode == 0)
352 		return (0);
353 
354 	return (VOP_ACCESS(ap->a_vp, accmode, ap->a_cred, ap->a_td));
355 }
356 
357 /*
358  * Advisory record locking support
359  */
360 int
361 vop_stdadvlock(struct vop_advlock_args *ap)
362 {
363 	struct vnode *vp;
364 	struct mount *mp;
365 	struct vattr vattr;
366 	int error;
367 
368 	vp = ap->a_vp;
369 
370 	/*
371 	 * Provide atomicity of open(O_CREAT | O_EXCL | O_EXLOCK) for
372 	 * local filesystems.  See vn_open_cred() for reciprocal part.
373 	 */
374 	mp = vp->v_mount;
375 	if (mp != NULL && (mp->mnt_flag & MNT_LOCAL) != 0 &&
376 	    ap->a_op == F_SETLK && (ap->a_flags & F_FIRSTOPEN) == 0) {
377 		VI_LOCK(vp);
378 		while ((vp->v_iflag & VI_FOPENING) != 0)
379 			msleep(vp, VI_MTX(vp), PLOCK, "lockfo", 0);
380 		VI_UNLOCK(vp);
381 	}
382 
383 	if (ap->a_fl->l_whence == SEEK_END) {
384 		/*
385 		 * The NFSv4 server must avoid doing a vn_lock() here, since it
386 		 * can deadlock the nfsd threads, due to a LOR.  Fortunately
387 		 * the NFSv4 server always uses SEEK_SET and this code is
388 		 * only required for the SEEK_END case.
389 		 */
390 		vn_lock(vp, LK_SHARED | LK_RETRY);
391 		error = VOP_GETATTR(vp, &vattr, curthread->td_ucred);
392 		VOP_UNLOCK(vp);
393 		if (error)
394 			return (error);
395 	} else
396 		vattr.va_size = 0;
397 
398 	return (lf_advlock(ap, &(vp->v_lockf), vattr.va_size));
399 }
400 
401 int
402 vop_stdadvlockasync(struct vop_advlockasync_args *ap)
403 {
404 	struct vnode *vp;
405 	struct vattr vattr;
406 	int error;
407 
408 	vp = ap->a_vp;
409 	if (ap->a_fl->l_whence == SEEK_END) {
410 		/* The size argument is only needed for SEEK_END. */
411 		vn_lock(vp, LK_SHARED | LK_RETRY);
412 		error = VOP_GETATTR(vp, &vattr, curthread->td_ucred);
413 		VOP_UNLOCK(vp);
414 		if (error)
415 			return (error);
416 	} else
417 		vattr.va_size = 0;
418 
419 	return (lf_advlockasync(ap, &(vp->v_lockf), vattr.va_size));
420 }
421 
422 int
423 vop_stdadvlockpurge(struct vop_advlockpurge_args *ap)
424 {
425 	struct vnode *vp;
426 
427 	vp = ap->a_vp;
428 	lf_purgelocks(vp, &vp->v_lockf);
429 	return (0);
430 }
431 
432 /*
433  * vop_stdpathconf:
434  *
435  * Standard implementation of POSIX pathconf, to get information about limits
436  * for a filesystem.
437  * Override per filesystem for the case where the filesystem has smaller
438  * limits.
439  */
440 int
441 vop_stdpathconf(struct vop_pathconf_args *ap)
442 {
443 
444 	switch (ap->a_name) {
445 		case _PC_ASYNC_IO:
446 			*ap->a_retval = _POSIX_ASYNCHRONOUS_IO;
447 			return (0);
448 		case _PC_PATH_MAX:
449 			*ap->a_retval = PATH_MAX;
450 			return (0);
451 		case _PC_ACL_EXTENDED:
452 		case _PC_ACL_NFS4:
453 		case _PC_CAP_PRESENT:
454 		case _PC_DEALLOC_PRESENT:
455 		case _PC_INF_PRESENT:
456 		case _PC_MAC_PRESENT:
457 			*ap->a_retval = 0;
458 			return (0);
459 		default:
460 			return (EINVAL);
461 	}
462 	/* NOTREACHED */
463 }
464 
465 /*
466  * Standard lock, unlock and islocked functions.
467  */
468 int
469 vop_stdlock(struct vop_lock1_args *ap)
470 {
471 	struct vnode *vp = ap->a_vp;
472 	struct mtx *ilk;
473 
474 	ilk = VI_MTX(vp);
475 	return (lockmgr_lock_flags(vp->v_vnlock, ap->a_flags,
476 	    &ilk->lock_object, ap->a_file, ap->a_line));
477 }
478 
479 /* See above. */
480 int
481 vop_stdunlock(struct vop_unlock_args *ap)
482 {
483 	struct vnode *vp = ap->a_vp;
484 
485 	return (lockmgr_unlock(vp->v_vnlock));
486 }
487 
488 /* See above. */
489 int
490 vop_stdislocked(struct vop_islocked_args *ap)
491 {
492 
493 	return (lockstatus(ap->a_vp->v_vnlock));
494 }
495 
496 /*
497  * Variants of the above set.
498  *
499  * Differences are:
500  * - shared locking disablement is not supported
501  * - v_vnlock pointer is not honored
502  */
503 int
504 vop_lock(struct vop_lock1_args *ap)
505 {
506 	struct vnode *vp = ap->a_vp;
507 	int flags = ap->a_flags;
508 	struct mtx *ilk;
509 
510 	MPASS(vp->v_vnlock == &vp->v_lock);
511 
512 	if (__predict_false((flags & ~(LK_TYPE_MASK | LK_NODDLKTREAT | LK_RETRY)) != 0))
513 		goto other;
514 
515 	switch (flags & LK_TYPE_MASK) {
516 	case LK_SHARED:
517 		return (lockmgr_slock(&vp->v_lock, flags, ap->a_file, ap->a_line));
518 	case LK_EXCLUSIVE:
519 		return (lockmgr_xlock(&vp->v_lock, flags, ap->a_file, ap->a_line));
520 	}
521 other:
522 	ilk = VI_MTX(vp);
523 	return (lockmgr_lock_flags(&vp->v_lock, flags,
524 	    &ilk->lock_object, ap->a_file, ap->a_line));
525 }
526 
527 int
528 vop_unlock(struct vop_unlock_args *ap)
529 {
530 	struct vnode *vp = ap->a_vp;
531 
532 	MPASS(vp->v_vnlock == &vp->v_lock);
533 
534 	return (lockmgr_unlock(&vp->v_lock));
535 }
536 
537 int
538 vop_islocked(struct vop_islocked_args *ap)
539 {
540 	struct vnode *vp = ap->a_vp;
541 
542 	MPASS(vp->v_vnlock == &vp->v_lock);
543 
544 	return (lockstatus(&vp->v_lock));
545 }
546 
547 /*
548  * Return true for select/poll.
549  */
550 int
551 vop_nopoll(struct vop_poll_args *ap)
552 {
553 
554 	if (ap->a_events & ~POLLSTANDARD)
555 		return (POLLNVAL);
556 	return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
557 }
558 
559 /*
560  * Implement poll for local filesystems that support it.
561  */
562 int
563 vop_stdpoll(struct vop_poll_args *ap)
564 {
565 	if (ap->a_events & ~POLLSTANDARD)
566 		return (vn_pollrecord(ap->a_vp, ap->a_td, ap->a_events));
567 	return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
568 }
569 
570 /*
571  * Return our mount point, as we will take charge of the writes.
572  */
573 int
574 vop_stdgetwritemount(struct vop_getwritemount_args *ap)
575 {
576 	struct mount *mp;
577 	struct vnode *vp;
578 
579 	/*
580 	 * Note that having a reference does not prevent forced unmount from
581 	 * setting ->v_mount to NULL after the lock gets released. This is of
582 	 * no consequence for typical consumers (most notably vn_start_write)
583 	 * since in this case the vnode is VIRF_DOOMED. Unmount might have
584 	 * progressed far enough that its completion is only delayed by the
585 	 * reference obtained here. The consumer only needs to concern itself
586 	 * with releasing it.
587 	 */
588 	vp = ap->a_vp;
589 	mp = vfs_ref_from_vp(vp);
590 	*(ap->a_mpp) = mp;
591 	return (0);
592 }
593 
594 /*
595  * If the file system doesn't implement VOP_BMAP, then return sensible defaults:
596  * - Return the vnode's bufobj instead of any underlying device's bufobj
597  * - Calculate the physical block number as if there were equal size
598  *   consecutive blocks, but
599  * - Report no contiguous runs of blocks.
600  */
601 int
602 vop_stdbmap(struct vop_bmap_args *ap)
603 {
604 
605 	if (ap->a_bop != NULL)
606 		*ap->a_bop = &ap->a_vp->v_bufobj;
607 	if (ap->a_bnp != NULL)
608 		*ap->a_bnp = ap->a_bn * btodb(ap->a_vp->v_mount->mnt_stat.f_iosize);
609 	if (ap->a_runp != NULL)
610 		*ap->a_runp = 0;
611 	if (ap->a_runb != NULL)
612 		*ap->a_runb = 0;
613 	return (0);
614 }
615 
616 int
617 vop_stdfsync(struct vop_fsync_args *ap)
618 {
619 
620 	return (vn_fsync_buf(ap->a_vp, ap->a_waitfor));
621 }
622 
623 static int
624 vop_stdfdatasync(struct vop_fdatasync_args *ap)
625 {
626 
627 	return (VOP_FSYNC(ap->a_vp, MNT_WAIT, ap->a_td));
628 }
629 
630 int
631 vop_stdfdatasync_buf(struct vop_fdatasync_args *ap)
632 {
633 
634 	return (vn_fsync_buf(ap->a_vp, MNT_WAIT));
635 }
636 
637 /* XXX Needs good comment and more info in the manpage (VOP_GETPAGES(9)). */
638 int
639 vop_stdgetpages(struct vop_getpages_args *ap)
640 {
641 
642 	return vnode_pager_generic_getpages(ap->a_vp, ap->a_m,
643 	    ap->a_count, ap->a_rbehind, ap->a_rahead, NULL, NULL);
644 }
645 
646 static int
647 vop_stdgetpages_async(struct vop_getpages_async_args *ap)
648 {
649 	int error;
650 
651 	error = VOP_GETPAGES(ap->a_vp, ap->a_m, ap->a_count, ap->a_rbehind,
652 	    ap->a_rahead);
653 	if (ap->a_iodone != NULL)
654 		ap->a_iodone(ap->a_arg, ap->a_m, ap->a_count, error);
655 	return (error);
656 }
657 
658 int
659 vop_stdkqfilter(struct vop_kqfilter_args *ap)
660 {
661 	return vfs_kqfilter(ap);
662 }
663 
664 /* XXX Needs good comment and more info in the manpage (VOP_PUTPAGES(9)). */
665 int
666 vop_stdputpages(struct vop_putpages_args *ap)
667 {
668 
669 	return vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count,
670 	     ap->a_sync, ap->a_rtvals);
671 }
672 
673 int
674 vop_stdvptofh(struct vop_vptofh_args *ap)
675 {
676 	return (EOPNOTSUPP);
677 }
678 
679 int
680 vop_stdvptocnp(struct vop_vptocnp_args *ap)
681 {
682 	struct vnode *const vp = ap->a_vp;
683 	struct vnode **const dvp = ap->a_vpp;
684 	char *buf = ap->a_buf;
685 	size_t *buflen = ap->a_buflen;
686 	char *dirbuf;
687 	int i = *buflen;
688 	int error = 0, covered = 0;
689 	int eofflag, flags, locked;
690 	size_t dirbuflen, len;
691 	off_t off;
692 	ino_t fileno;
693 	struct vattr va;
694 	struct nameidata nd;
695 	struct thread *const td = curthread;
696 	struct ucred *const cred = td->td_ucred;
697 	struct dirent *dp;
698 	struct vnode *mvp;
699 
700 	if (vp->v_type != VDIR)
701 		return (ENOENT);
702 
703 	error = VOP_GETATTR(vp, &va, cred);
704 	if (error)
705 		return (error);
706 
707 	VREF(vp);
708 	locked = VOP_ISLOCKED(vp);
709 	VOP_UNLOCK(vp);
710 	NDINIT_ATVP(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF, UIO_SYSSPACE,
711 	    "..", vp);
712 	flags = FREAD;
713 	error = vn_open_cred(&nd, &flags, 0, VN_OPEN_NOAUDIT, cred, NULL);
714 	if (error) {
715 		vn_lock(vp, locked | LK_RETRY);
716 		return (error);
717 	}
718 	NDFREE_PNBUF(&nd);
719 
720 	mvp = *dvp = nd.ni_vp;
721 
722 	if (vp->v_mount != (*dvp)->v_mount &&
723 	    ((*dvp)->v_vflag & VV_ROOT) &&
724 	    ((*dvp)->v_mount->mnt_flag & MNT_UNION)) {
725 		*dvp = (*dvp)->v_mount->mnt_vnodecovered;
726 		VREF(mvp);
727 		VOP_UNLOCK(mvp);
728 		vn_close(mvp, FREAD, cred, td);
729 		VREF(*dvp);
730 		vn_lock(*dvp, LK_SHARED | LK_RETRY);
731 		covered = 1;
732 	}
733 
734 	fileno = va.va_fileid;
735 
736 	dirbuflen = MAX(DEV_BSIZE, GENERIC_MAXDIRSIZ);
737 	if (dirbuflen < va.va_blocksize)
738 		dirbuflen = va.va_blocksize;
739 	dirbuf = malloc(dirbuflen, M_TEMP, M_WAITOK);
740 
741 	if ((*dvp)->v_type != VDIR) {
742 		error = ENOENT;
743 		goto out;
744 	}
745 
746 	len = 0;
747 	off = 0;
748 	eofflag = 0;
749 
750 	for (;;) {
751 		/* call VOP_READDIR of parent */
752 		error = vn_dir_next_dirent(*dvp, td,
753 		    dirbuf, dirbuflen, &dp, &len, &off, &eofflag);
754 		if (error != 0)
755 			goto out;
756 
757 		if (len == 0) {
758 			error = ENOENT;
759 			goto out;
760 		}
761 
762 		if ((dp->d_type != DT_WHT) &&
763 		    (dp->d_fileno == fileno)) {
764 			if (covered) {
765 				VOP_UNLOCK(*dvp);
766 				vn_lock(mvp, LK_SHARED | LK_RETRY);
767 				if (dirent_exists(mvp, dp->d_name, td) == 0) {
768 					error = ENOENT;
769 					VOP_UNLOCK(mvp);
770 					vn_lock(*dvp, LK_SHARED | LK_RETRY);
771 					goto out;
772 				}
773 				VOP_UNLOCK(mvp);
774 				vn_lock(*dvp, LK_SHARED | LK_RETRY);
775 			}
776 			i -= dp->d_namlen;
777 
778 			if (i < 0) {
779 				error = ENOMEM;
780 				goto out;
781 			}
782 			if (dp->d_namlen == 1 && dp->d_name[0] == '.') {
783 				error = ENOENT;
784 			} else {
785 				bcopy(dp->d_name, buf + i, dp->d_namlen);
786 				error = 0;
787 			}
788 			goto out;
789 		}
790 	}
791 
792 out:
793 	free(dirbuf, M_TEMP);
794 	if (!error) {
795 		*buflen = i;
796 		vref(*dvp);
797 	}
798 	if (covered) {
799 		vput(*dvp);
800 		vrele(mvp);
801 	} else {
802 		VOP_UNLOCK(mvp);
803 		vn_close(mvp, FREAD, cred, td);
804 	}
805 	vn_lock(vp, locked | LK_RETRY);
806 	return (error);
807 }
808 
809 int
810 vop_stdallocate(struct vop_allocate_args *ap)
811 {
812 #ifdef __notyet__
813 	struct statfs *sfs;
814 	off_t maxfilesize = 0;
815 #endif
816 	struct iovec aiov;
817 	struct vattr vattr, *vap;
818 	struct uio auio;
819 	off_t fsize, len, cur, offset;
820 	uint8_t *buf;
821 	struct thread *td;
822 	struct vnode *vp;
823 	size_t iosize;
824 	int error;
825 
826 	buf = NULL;
827 	error = 0;
828 	td = curthread;
829 	vap = &vattr;
830 	vp = ap->a_vp;
831 	len = *ap->a_len;
832 	offset = *ap->a_offset;
833 
834 	error = VOP_GETATTR(vp, vap, ap->a_cred);
835 	if (error != 0)
836 		goto out;
837 	fsize = vap->va_size;
838 	iosize = vap->va_blocksize;
839 	if (iosize == 0)
840 		iosize = BLKDEV_IOSIZE;
841 	if (iosize > maxphys)
842 		iosize = maxphys;
843 	buf = malloc(iosize, M_TEMP, M_WAITOK);
844 
845 #ifdef __notyet__
846 	/*
847 	 * Check if the filesystem sets f_maxfilesize; if not use
848 	 * VOP_SETATTR to perform the check.
849 	 */
850 	sfs = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK);
851 	error = VFS_STATFS(vp->v_mount, sfs, td);
852 	if (error == 0)
853 		maxfilesize = sfs->f_maxfilesize;
854 	free(sfs, M_STATFS);
855 	if (error != 0)
856 		goto out;
857 	if (maxfilesize) {
858 		if (offset > maxfilesize || len > maxfilesize ||
859 		    offset + len > maxfilesize) {
860 			error = EFBIG;
861 			goto out;
862 		}
863 	} else
864 #endif
865 	if (offset + len > vap->va_size) {
866 		/*
867 		 * Test offset + len against the filesystem's maxfilesize.
868 		 */
869 		VATTR_NULL(vap);
870 		vap->va_size = offset + len;
871 		error = VOP_SETATTR(vp, vap, ap->a_cred);
872 		if (error != 0)
873 			goto out;
874 		VATTR_NULL(vap);
875 		vap->va_size = fsize;
876 		error = VOP_SETATTR(vp, vap, ap->a_cred);
877 		if (error != 0)
878 			goto out;
879 	}
880 
881 	for (;;) {
882 		/*
883 		 * Read and write back anything below the nominal file
884 		 * size.  There's currently no way outside the filesystem
885 		 * to know whether this area is sparse or not.
886 		 */
887 		cur = iosize;
888 		if ((offset % iosize) != 0)
889 			cur -= (offset % iosize);
890 		if (cur > len)
891 			cur = len;
892 		if (offset < fsize) {
893 			aiov.iov_base = buf;
894 			aiov.iov_len = cur;
895 			auio.uio_iov = &aiov;
896 			auio.uio_iovcnt = 1;
897 			auio.uio_offset = offset;
898 			auio.uio_resid = cur;
899 			auio.uio_segflg = UIO_SYSSPACE;
900 			auio.uio_rw = UIO_READ;
901 			auio.uio_td = td;
902 			error = VOP_READ(vp, &auio, ap->a_ioflag, ap->a_cred);
903 			if (error != 0)
904 				break;
905 			if (auio.uio_resid > 0) {
906 				bzero(buf + cur - auio.uio_resid,
907 				    auio.uio_resid);
908 			}
909 		} else {
910 			bzero(buf, cur);
911 		}
912 
913 		aiov.iov_base = buf;
914 		aiov.iov_len = cur;
915 		auio.uio_iov = &aiov;
916 		auio.uio_iovcnt = 1;
917 		auio.uio_offset = offset;
918 		auio.uio_resid = cur;
919 		auio.uio_segflg = UIO_SYSSPACE;
920 		auio.uio_rw = UIO_WRITE;
921 		auio.uio_td = td;
922 
923 		error = VOP_WRITE(vp, &auio, ap->a_ioflag, ap->a_cred);
924 		if (error != 0)
925 			break;
926 
927 		len -= cur;
928 		offset += cur;
929 		if (len == 0)
930 			break;
931 		if (should_yield())
932 			break;
933 	}
934 
935  out:
936 	*ap->a_len = len;
937 	*ap->a_offset = offset;
938 	free(buf, M_TEMP);
939 	return (error);
940 }
941 
942 static int
943 vp_zerofill(struct vnode *vp, struct vattr *vap, off_t *offsetp, off_t *lenp,
944     int ioflag, struct ucred *cred)
945 {
946 	int iosize;
947 	int error = 0;
948 	struct iovec aiov;
949 	struct uio auio;
950 	struct thread *td;
951 	off_t offset, len;
952 
953 	iosize = vap->va_blocksize;
954 	td = curthread;
955 	offset = *offsetp;
956 	len = *lenp;
957 
958 	if (iosize == 0)
959 		iosize = BLKDEV_IOSIZE;
960 	/* If va_blocksize is 512 bytes, iosize will be 4 kilobytes */
961 	iosize = min(iosize * 8, ZERO_REGION_SIZE);
962 
963 	while (len > 0) {
964 		int xfersize = iosize;
965 		if (offset % iosize != 0)
966 			xfersize -= offset % iosize;
967 		if (xfersize > len)
968 			xfersize = len;
969 
970 		aiov.iov_base = __DECONST(void *, zero_region);
971 		aiov.iov_len = xfersize;
972 		auio.uio_iov = &aiov;
973 		auio.uio_iovcnt = 1;
974 		auio.uio_offset = offset;
975 		auio.uio_resid = xfersize;
976 		auio.uio_segflg = UIO_SYSSPACE;
977 		auio.uio_rw = UIO_WRITE;
978 		auio.uio_td = td;
979 
980 		error = VOP_WRITE(vp, &auio, ioflag, cred);
981 		if (error != 0) {
982 			len -= xfersize - auio.uio_resid;
983 			offset += xfersize - auio.uio_resid;
984 			break;
985 		}
986 
987 		len -= xfersize;
988 		offset += xfersize;
989 	}
990 
991 	*offsetp = offset;
992 	*lenp = len;
993 	return (error);
994 }
995 
996 int
997 vop_stddeallocate(struct vop_deallocate_args *ap)
998 {
999 	struct vnode *vp;
1000 	off_t offset, len;
1001 	struct ucred *cred;
1002 	int error;
1003 	struct vattr va;
1004 	off_t noff, xfersize, rem;
1005 
1006 	vp = ap->a_vp;
1007 	offset = *ap->a_offset;
1008 	cred = ap->a_cred;
1009 
1010 	error = VOP_GETATTR(vp, &va, cred);
1011 	if (error)
1012 		return (error);
1013 
1014 	len = omin((off_t)va.va_size - offset, *ap->a_len);
1015 	while (len > 0) {
1016 		noff = offset;
1017 		error = vn_bmap_seekhole_locked(vp, FIOSEEKDATA, &noff, cred);
1018 		if (error) {
1019 			if (error != ENXIO)
1020 				/* XXX: Is it okay to fallback further? */
1021 				goto out;
1022 
1023 			/*
1024 			 * No more data region to be filled
1025 			 */
1026 			offset += len;
1027 			len = 0;
1028 			error = 0;
1029 			break;
1030 		}
1031 		KASSERT(noff >= offset, ("FIOSEEKDATA going backward"));
1032 		if (noff != offset) {
1033 			xfersize = omin(noff - offset, len);
1034 			len -= xfersize;
1035 			offset += xfersize;
1036 			if (len == 0)
1037 				break;
1038 		}
1039 		error = vn_bmap_seekhole_locked(vp, FIOSEEKHOLE, &noff, cred);
1040 		if (error)
1041 			goto out;
1042 
1043 		/* Fill zeroes */
1044 		xfersize = rem = omin(noff - offset, len);
1045 		error = vp_zerofill(vp, &va, &offset, &rem, ap->a_ioflag, cred);
1046 		if (error) {
1047 			len -= xfersize - rem;
1048 			goto out;
1049 		}
1050 
1051 		len -= xfersize;
1052 		if (should_yield())
1053 			break;
1054 	}
1055 	/* Handle the case when offset is beyond EOF */
1056 	if (len < 0)
1057 		len = 0;
1058 out:
1059 	*ap->a_offset = offset;
1060 	*ap->a_len = len;
1061 	return (error);
1062 }
1063 
1064 int
1065 vop_stdadvise(struct vop_advise_args *ap)
1066 {
1067 	struct vnode *vp;
1068 	struct bufobj *bo;
1069 	daddr_t startn, endn;
1070 	off_t bstart, bend, start, end;
1071 	int bsize, error;
1072 
1073 	vp = ap->a_vp;
1074 	switch (ap->a_advice) {
1075 	case POSIX_FADV_WILLNEED:
1076 		/*
1077 		 * Do nothing for now.  Filesystems should provide a
1078 		 * custom method which starts an asynchronous read of
1079 		 * the requested region.
1080 		 */
1081 		error = 0;
1082 		break;
1083 	case POSIX_FADV_DONTNEED:
1084 		error = 0;
1085 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1086 		if (VN_IS_DOOMED(vp)) {
1087 			VOP_UNLOCK(vp);
1088 			break;
1089 		}
1090 
1091 		/*
1092 		 * Round to block boundaries (and later possibly further to
1093 		 * page boundaries).  Applications cannot reasonably be aware
1094 		 * of the boundaries, and the rounding must be to expand at
1095 		 * both extremities to cover enough.  It still doesn't cover
1096 		 * read-ahead.  For partial blocks, this gives unnecessary
1097 		 * discarding of buffers but is efficient enough since the
1098 		 * pages usually remain in VMIO for some time.
1099 		 */
1100 		bsize = vp->v_bufobj.bo_bsize;
1101 		bstart = rounddown(ap->a_start, bsize);
1102 		bend = roundup(ap->a_end, bsize);
1103 
1104 		/*
1105 		 * Deactivate pages in the specified range from the backing VM
1106 		 * object.  Pages that are resident in the buffer cache will
1107 		 * remain wired until their corresponding buffers are released
1108 		 * below.
1109 		 */
1110 		if (vp->v_object != NULL) {
1111 			start = trunc_page(bstart);
1112 			end = round_page(bend);
1113 			VM_OBJECT_RLOCK(vp->v_object);
1114 			vm_object_page_noreuse(vp->v_object, OFF_TO_IDX(start),
1115 			    OFF_TO_IDX(end));
1116 			VM_OBJECT_RUNLOCK(vp->v_object);
1117 		}
1118 
1119 		bo = &vp->v_bufobj;
1120 		BO_RLOCK(bo);
1121 		startn = bstart / bsize;
1122 		endn = bend / bsize;
1123 		error = bnoreuselist(&bo->bo_clean, bo, startn, endn);
1124 		if (error == 0)
1125 			error = bnoreuselist(&bo->bo_dirty, bo, startn, endn);
1126 		BO_RUNLOCK(bo);
1127 		VOP_UNLOCK(vp);
1128 		break;
1129 	default:
1130 		error = EINVAL;
1131 		break;
1132 	}
1133 	return (error);
1134 }
1135 
1136 int
1137 vop_stdunp_bind(struct vop_unp_bind_args *ap)
1138 {
1139 
1140 	ap->a_vp->v_unpcb = ap->a_unpcb;
1141 	return (0);
1142 }
1143 
1144 int
1145 vop_stdunp_connect(struct vop_unp_connect_args *ap)
1146 {
1147 
1148 	*ap->a_unpcb = ap->a_vp->v_unpcb;
1149 	return (0);
1150 }
1151 
1152 int
1153 vop_stdunp_detach(struct vop_unp_detach_args *ap)
1154 {
1155 
1156 	ap->a_vp->v_unpcb = NULL;
1157 	return (0);
1158 }
1159 
1160 static int
1161 vop_stdis_text(struct vop_is_text_args *ap)
1162 {
1163 
1164 	return (atomic_load_int(&ap->a_vp->v_writecount) < 0);
1165 }
1166 
1167 int
1168 vop_stdset_text(struct vop_set_text_args *ap)
1169 {
1170 	struct vnode *vp;
1171 	int n;
1172 	bool gotref;
1173 
1174 	vp = ap->a_vp;
1175 
1176 	n = atomic_load_int(&vp->v_writecount);
1177 	for (;;) {
1178 		if (__predict_false(n > 0)) {
1179 			return (ETXTBSY);
1180 		}
1181 
1182 		/*
1183 		 * Transition point, we may need to grab a reference on the vnode.
1184 		 *
1185 		 * Take the ref early As a safety measure against bogus calls
1186 		 * to vop_stdunset_text.
1187 		 */
1188 		if (n == 0) {
1189 			gotref = false;
1190 			if ((vn_irflag_read(vp) & VIRF_TEXT_REF) != 0) {
1191 				vref(vp);
1192 				gotref = true;
1193 			}
1194 			if (atomic_fcmpset_int(&vp->v_writecount, &n, -1)) {
1195 				return (0);
1196 			}
1197 			if (gotref) {
1198 				vunref(vp);
1199 			}
1200 			continue;
1201 		}
1202 
1203 		MPASS(n < 0);
1204 		if (atomic_fcmpset_int(&vp->v_writecount, &n, n - 1)) {
1205 			return (0);
1206 		}
1207 	}
1208 	__assert_unreachable();
1209 }
1210 
1211 static int
1212 vop_stdunset_text(struct vop_unset_text_args *ap)
1213 {
1214 	struct vnode *vp;
1215 	int n;
1216 
1217 	vp = ap->a_vp;
1218 
1219 	n = atomic_load_int(&vp->v_writecount);
1220 	for (;;) {
1221 		if (__predict_false(n >= 0)) {
1222 			return (EINVAL);
1223 		}
1224 
1225 		/*
1226 		 * Transition point, we may need to release a reference on the vnode.
1227 		 */
1228 		if (n == -1) {
1229 			if (atomic_fcmpset_int(&vp->v_writecount, &n, 0)) {
1230 				if ((vn_irflag_read(vp) & VIRF_TEXT_REF) != 0) {
1231 					vunref(vp);
1232 				}
1233 				return (0);
1234 			}
1235 			continue;
1236 		}
1237 
1238 		MPASS(n < -1);
1239 		if (atomic_fcmpset_int(&vp->v_writecount, &n, n + 1)) {
1240 			return (0);
1241 		}
1242 	}
1243 	__assert_unreachable();
1244 }
1245 
1246 static int __always_inline
1247 vop_stdadd_writecount_impl(struct vop_add_writecount_args *ap, bool handle_msync)
1248 {
1249 	struct vnode *vp;
1250 	struct mount *mp __diagused;
1251 	int n;
1252 
1253 	vp = ap->a_vp;
1254 
1255 #ifdef INVARIANTS
1256 	mp = vp->v_mount;
1257 	if (mp != NULL) {
1258 		if (handle_msync) {
1259 			VNPASS((mp->mnt_kern_flag & MNTK_NOMSYNC) == 0, vp);
1260 		} else {
1261 			VNPASS((mp->mnt_kern_flag & MNTK_NOMSYNC) != 0, vp);
1262 		}
1263 	}
1264 #endif
1265 
1266 	n = atomic_load_int(&vp->v_writecount);
1267 	for (;;) {
1268 		if (__predict_false(n < 0)) {
1269 			return (ETXTBSY);
1270 		}
1271 
1272 		VNASSERT(n + ap->a_inc >= 0, vp,
1273 		    ("neg writecount increment %d + %d = %d", n, ap->a_inc,
1274 		    n + ap->a_inc));
1275 		if (n == 0) {
1276 			if (handle_msync) {
1277 				vlazy(vp);
1278 			}
1279 		}
1280 
1281 		if (atomic_fcmpset_int(&vp->v_writecount, &n, n + ap->a_inc)) {
1282 			return (0);
1283 		}
1284 	}
1285 	__assert_unreachable();
1286 }
1287 
1288 int
1289 vop_stdadd_writecount(struct vop_add_writecount_args *ap)
1290 {
1291 
1292 	return (vop_stdadd_writecount_impl(ap, true));
1293 }
1294 
1295 int
1296 vop_stdadd_writecount_nomsync(struct vop_add_writecount_args *ap)
1297 {
1298 
1299 	return (vop_stdadd_writecount_impl(ap, false));
1300 }
1301 
1302 int
1303 vop_stdneed_inactive(struct vop_need_inactive_args *ap)
1304 {
1305 
1306 	return (1);
1307 }
1308 
1309 int
1310 vop_stdioctl(struct vop_ioctl_args *ap)
1311 {
1312 	struct vnode *vp;
1313 	struct vattr va;
1314 	off_t *offp;
1315 	int error;
1316 
1317 	switch (ap->a_command) {
1318 	case FIOSEEKDATA:
1319 	case FIOSEEKHOLE:
1320 		vp = ap->a_vp;
1321 		error = vn_lock(vp, LK_SHARED);
1322 		if (error != 0)
1323 			return (EBADF);
1324 		if (vp->v_type == VREG)
1325 			error = VOP_GETATTR(vp, &va, ap->a_cred);
1326 		else
1327 			error = ENOTTY;
1328 		if (error == 0) {
1329 			offp = ap->a_data;
1330 			if (*offp < 0 || *offp >= va.va_size)
1331 				error = ENXIO;
1332 			else if (ap->a_command == FIOSEEKHOLE)
1333 				*offp = va.va_size;
1334 		}
1335 		VOP_UNLOCK(vp);
1336 		break;
1337 	default:
1338 		error = ENOTTY;
1339 		break;
1340 	}
1341 	return (error);
1342 }
1343 
1344 /*
1345  * vfs default ops
1346  * used to fill the vfs function table to get reasonable default return values.
1347  */
1348 int
1349 vfs_stdroot(struct mount *mp, int flags, struct vnode **vpp)
1350 {
1351 
1352 	return (EOPNOTSUPP);
1353 }
1354 
1355 int
1356 vfs_stdstatfs(struct mount *mp, struct statfs *sbp)
1357 {
1358 
1359 	return (EOPNOTSUPP);
1360 }
1361 
1362 int
1363 vfs_stdquotactl(struct mount *mp, int cmds, uid_t uid, void *arg, bool *mp_busy)
1364 {
1365 	return (EOPNOTSUPP);
1366 }
1367 
1368 int
1369 vfs_stdsync(struct mount *mp, int waitfor)
1370 {
1371 	struct vnode *vp, *mvp;
1372 	struct thread *td;
1373 	int error, lockreq, allerror = 0;
1374 
1375 	td = curthread;
1376 	lockreq = LK_EXCLUSIVE | LK_INTERLOCK;
1377 	if (waitfor != MNT_WAIT)
1378 		lockreq |= LK_NOWAIT;
1379 	/*
1380 	 * Force stale buffer cache information to be flushed.
1381 	 */
1382 loop:
1383 	MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
1384 		if (vp->v_bufobj.bo_dirty.bv_cnt == 0) {
1385 			VI_UNLOCK(vp);
1386 			continue;
1387 		}
1388 		if ((error = vget(vp, lockreq)) != 0) {
1389 			if (error == ENOENT) {
1390 				MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
1391 				goto loop;
1392 			}
1393 			continue;
1394 		}
1395 		error = VOP_FSYNC(vp, waitfor, td);
1396 		if (error)
1397 			allerror = error;
1398 		vput(vp);
1399 	}
1400 	return (allerror);
1401 }
1402 
1403 int
1404 vfs_stdnosync(struct mount *mp, int waitfor)
1405 {
1406 
1407 	return (0);
1408 }
1409 
1410 static int
1411 vop_stdcopy_file_range(struct vop_copy_file_range_args *ap)
1412 {
1413 	int error;
1414 
1415 	error = vn_generic_copy_file_range(ap->a_invp, ap->a_inoffp,
1416 	    ap->a_outvp, ap->a_outoffp, ap->a_lenp, ap->a_flags, ap->a_incred,
1417 	    ap->a_outcred, ap->a_fsizetd);
1418 	return (error);
1419 }
1420 
1421 int
1422 vfs_stdvget(struct mount *mp, ino_t ino, int flags, struct vnode **vpp)
1423 {
1424 
1425 	return (EOPNOTSUPP);
1426 }
1427 
1428 int
1429 vfs_stdfhtovp(struct mount *mp, struct fid *fhp, int flags, struct vnode **vpp)
1430 {
1431 
1432 	return (EOPNOTSUPP);
1433 }
1434 
1435 int
1436 vfs_stdinit(struct vfsconf *vfsp)
1437 {
1438 
1439 	return (0);
1440 }
1441 
1442 int
1443 vfs_stduninit(struct vfsconf *vfsp)
1444 {
1445 
1446 	return(0);
1447 }
1448 
1449 int
1450 vfs_stdextattrctl(struct mount *mp, int cmd, struct vnode *filename_vp,
1451     int attrnamespace, const char *attrname)
1452 {
1453 
1454 	if (filename_vp != NULL)
1455 		VOP_UNLOCK(filename_vp);
1456 	return (EOPNOTSUPP);
1457 }
1458 
1459 int
1460 vfs_stdsysctl(struct mount *mp, fsctlop_t op, struct sysctl_req *req)
1461 {
1462 
1463 	return (EOPNOTSUPP);
1464 }
1465 
1466 static vop_bypass_t *
1467 bp_by_off(struct vop_vector *vop, struct vop_generic_args *a)
1468 {
1469 
1470 	return (*(vop_bypass_t **)((char *)vop + a->a_desc->vdesc_vop_offset));
1471 }
1472 
1473 int
1474 vop_sigdefer(struct vop_vector *vop, struct vop_generic_args *a)
1475 {
1476 	vop_bypass_t *bp;
1477 	int prev_stops, rc;
1478 
1479 	bp = bp_by_off(vop, a);
1480 	MPASS(bp != NULL);
1481 
1482 	prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
1483 	rc = bp(a);
1484 	sigallowstop(prev_stops);
1485 	return (rc);
1486 }
1487 
1488 static int
1489 vop_stdstat(struct vop_stat_args *a)
1490 {
1491 	struct vattr vattr;
1492 	struct vattr *vap;
1493 	struct vnode *vp;
1494 	struct stat *sb;
1495 	int error;
1496 	u_short mode;
1497 
1498 	vp = a->a_vp;
1499 	sb = a->a_sb;
1500 
1501 	error = vop_stat_helper_pre(a);
1502 	if (error != 0)
1503 		return (error);
1504 
1505 	vap = &vattr;
1506 
1507 	/*
1508 	 * Initialize defaults for new and unusual fields, so that file
1509 	 * systems which don't support these fields don't need to know
1510 	 * about them.
1511 	 */
1512 	vap->va_birthtime.tv_sec = -1;
1513 	vap->va_birthtime.tv_nsec = 0;
1514 	vap->va_fsid = VNOVAL;
1515 	vap->va_gen = 0;
1516 	vap->va_rdev = NODEV;
1517 
1518 	error = VOP_GETATTR(vp, vap, a->a_active_cred);
1519 	if (error)
1520 		goto out;
1521 
1522 	/*
1523 	 * Zero the spare stat fields
1524 	 */
1525 	bzero(sb, sizeof *sb);
1526 
1527 	/*
1528 	 * Copy from vattr table
1529 	 */
1530 	if (vap->va_fsid != VNOVAL)
1531 		sb->st_dev = vap->va_fsid;
1532 	else
1533 		sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0];
1534 	sb->st_ino = vap->va_fileid;
1535 	mode = vap->va_mode;
1536 	switch (vap->va_type) {
1537 	case VREG:
1538 		mode |= S_IFREG;
1539 		break;
1540 	case VDIR:
1541 		mode |= S_IFDIR;
1542 		break;
1543 	case VBLK:
1544 		mode |= S_IFBLK;
1545 		break;
1546 	case VCHR:
1547 		mode |= S_IFCHR;
1548 		break;
1549 	case VLNK:
1550 		mode |= S_IFLNK;
1551 		break;
1552 	case VSOCK:
1553 		mode |= S_IFSOCK;
1554 		break;
1555 	case VFIFO:
1556 		mode |= S_IFIFO;
1557 		break;
1558 	default:
1559 		error = EBADF;
1560 		goto out;
1561 	}
1562 	sb->st_mode = mode;
1563 	sb->st_nlink = vap->va_nlink;
1564 	sb->st_uid = vap->va_uid;
1565 	sb->st_gid = vap->va_gid;
1566 	sb->st_rdev = vap->va_rdev;
1567 	if (vap->va_size > OFF_MAX) {
1568 		error = EOVERFLOW;
1569 		goto out;
1570 	}
1571 	sb->st_size = vap->va_size;
1572 	sb->st_atim.tv_sec = vap->va_atime.tv_sec;
1573 	sb->st_atim.tv_nsec = vap->va_atime.tv_nsec;
1574 	sb->st_mtim.tv_sec = vap->va_mtime.tv_sec;
1575 	sb->st_mtim.tv_nsec = vap->va_mtime.tv_nsec;
1576 	sb->st_ctim.tv_sec = vap->va_ctime.tv_sec;
1577 	sb->st_ctim.tv_nsec = vap->va_ctime.tv_nsec;
1578 	sb->st_birthtim.tv_sec = vap->va_birthtime.tv_sec;
1579 	sb->st_birthtim.tv_nsec = vap->va_birthtime.tv_nsec;
1580 
1581 	/*
1582 	 * According to www.opengroup.org, the meaning of st_blksize is
1583 	 *   "a filesystem-specific preferred I/O block size for this
1584 	 *    object.  In some filesystem types, this may vary from file
1585 	 *    to file"
1586 	 * Use minimum/default of PAGE_SIZE (e.g. for VCHR).
1587 	 */
1588 
1589 	sb->st_blksize = max(PAGE_SIZE, vap->va_blocksize);
1590 	sb->st_flags = vap->va_flags;
1591 	sb->st_blocks = vap->va_bytes / S_BLKSIZE;
1592 	sb->st_gen = vap->va_gen;
1593 out:
1594 	return (vop_stat_helper_post(a, error));
1595 }
1596 
1597 static int
1598 vop_stdread_pgcache(struct vop_read_pgcache_args *ap __unused)
1599 {
1600 	return (EJUSTRETURN);
1601 }
1602 
1603 static int
1604 vop_stdvput_pair(struct vop_vput_pair_args *ap)
1605 {
1606 	struct vnode *dvp, *vp, **vpp;
1607 
1608 	dvp = ap->a_dvp;
1609 	vpp = ap->a_vpp;
1610 	vput(dvp);
1611 	if (vpp != NULL && ap->a_unlock_vp && (vp = *vpp) != NULL)
1612 		vput(vp);
1613 	return (0);
1614 }
1615