xref: /freebsd/sys/kern/vfs_default.c (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
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  * 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 
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/bio.h>
38 #include <sys/buf.h>
39 #include <sys/conf.h>
40 #include <sys/event.h>
41 #include <sys/filio.h>
42 #include <sys/kernel.h>
43 #include <sys/limits.h>
44 #include <sys/lock.h>
45 #include <sys/lockf.h>
46 #include <sys/malloc.h>
47 #include <sys/mount.h>
48 #include <sys/namei.h>
49 #include <sys/rwlock.h>
50 #include <sys/fcntl.h>
51 #include <sys/unistd.h>
52 #include <sys/vnode.h>
53 #include <sys/dirent.h>
54 #include <sys/poll.h>
55 #include <sys/stat.h>
56 #include <security/audit/audit.h>
57 #include <sys/priv.h>
58 
59 #include <security/mac/mac_framework.h>
60 
61 #include <vm/vm.h>
62 #include <vm/vm_object.h>
63 #include <vm/vm_extern.h>
64 #include <vm/pmap.h>
65 #include <vm/vm_map.h>
66 #include <vm/vm_page.h>
67 #include <vm/vm_pager.h>
68 #include <vm/vnode_pager.h>
69 
70 static int	vop_nolookup(struct vop_lookup_args *);
71 static int	vop_norename(struct vop_rename_args *);
72 static int	vop_nostrategy(struct vop_strategy_args *);
73 static int	dirent_exists(struct vnode *vp, const char *dirname,
74 			      struct thread *td);
75 
76 static int vop_stdis_text(struct vop_is_text_args *ap);
77 static int vop_stdunset_text(struct vop_unset_text_args *ap);
78 static int vop_stdadd_writecount(struct vop_add_writecount_args *ap);
79 static int vop_stdcopy_file_range(struct vop_copy_file_range_args *ap);
80 static int vop_stdfdatasync(struct vop_fdatasync_args *ap);
81 static int vop_stdgetpages_async(struct vop_getpages_async_args *ap);
82 static int vop_stdread_pgcache(struct vop_read_pgcache_args *ap);
83 static int vop_stdstat(struct vop_stat_args *ap);
84 static int vop_stdvput_pair(struct vop_vput_pair_args *ap);
85 static int vop_stdgetlowvnode(struct vop_getlowvnode_args *ap);
86 
87 /*
88  * This vnode table stores what we want to do if the filesystem doesn't
89  * implement a particular VOP.
90  *
91  * If there is no specific entry here, we will return EOPNOTSUPP.
92  *
93  * Note that every filesystem has to implement either vop_access
94  * or vop_accessx; failing to do so will result in immediate crash
95  * due to stack overflow, as vop_stdaccess() calls vop_stdaccessx(),
96  * which calls vop_stdaccess() etc.
97  */
98 
99 struct vop_vector default_vnodeops = {
100 	.vop_default =		NULL,
101 	.vop_bypass =		VOP_EOPNOTSUPP,
102 
103 	.vop_access =		vop_stdaccess,
104 	.vop_accessx =		vop_stdaccessx,
105 	.vop_advise =		vop_stdadvise,
106 	.vop_advlock =		vop_stdadvlock,
107 	.vop_advlockasync =	vop_stdadvlockasync,
108 	.vop_advlockpurge =	vop_stdadvlockpurge,
109 	.vop_allocate =		vop_stdallocate,
110 	.vop_deallocate =	vop_stddeallocate,
111 	.vop_bmap =		vop_stdbmap,
112 	.vop_close =		VOP_NULL,
113 	.vop_fsync =		VOP_NULL,
114 	.vop_stat =		vop_stdstat,
115 	.vop_fdatasync =	vop_stdfdatasync,
116 	.vop_getlowvnode = 	vop_stdgetlowvnode,
117 	.vop_getpages =		vop_stdgetpages,
118 	.vop_getpages_async =	vop_stdgetpages_async,
119 	.vop_getwritemount = 	vop_stdgetwritemount,
120 	.vop_inactive =		VOP_NULL,
121 	.vop_need_inactive =	vop_stdneed_inactive,
122 	.vop_ioctl =		vop_stdioctl,
123 	.vop_kqfilter =		vop_stdkqfilter,
124 	.vop_islocked =		vop_stdislocked,
125 	.vop_lock1 =		vop_stdlock,
126 	.vop_lookup =		vop_nolookup,
127 	.vop_open =		VOP_NULL,
128 	.vop_pathconf =		VOP_EINVAL,
129 	.vop_poll =		vop_nopoll,
130 	.vop_putpages =		vop_stdputpages,
131 	.vop_readlink =		VOP_EINVAL,
132 	.vop_read_pgcache =	vop_stdread_pgcache,
133 	.vop_rename =		vop_norename,
134 	.vop_revoke =		VOP_PANIC,
135 	.vop_strategy =		vop_nostrategy,
136 	.vop_unlock =		vop_stdunlock,
137 	.vop_vptocnp =		vop_stdvptocnp,
138 	.vop_vptofh =		vop_stdvptofh,
139 	.vop_unp_bind =		vop_stdunp_bind,
140 	.vop_unp_connect =	vop_stdunp_connect,
141 	.vop_unp_detach =	vop_stdunp_detach,
142 	.vop_is_text =		vop_stdis_text,
143 	.vop_set_text =		vop_stdset_text,
144 	.vop_unset_text =	vop_stdunset_text,
145 	.vop_add_writecount =	vop_stdadd_writecount,
146 	.vop_copy_file_range =	vop_stdcopy_file_range,
147 	.vop_vput_pair =	vop_stdvput_pair,
148 };
149 VFS_VOP_VECTOR_REGISTER(default_vnodeops);
150 
151 /*
152  * Series of placeholder functions for various error returns for
153  * VOPs.
154  */
155 
156 int
157 vop_eopnotsupp(struct vop_generic_args *ap)
158 {
159 	/*
160 	printf("vop_notsupp[%s]\n", ap->a_desc->vdesc_name);
161 	*/
162 
163 	return (EOPNOTSUPP);
164 }
165 
166 int
167 vop_ebadf(struct vop_generic_args *ap)
168 {
169 
170 	return (EBADF);
171 }
172 
173 int
174 vop_enotty(struct vop_generic_args *ap)
175 {
176 
177 	return (ENOTTY);
178 }
179 
180 int
181 vop_einval(struct vop_generic_args *ap)
182 {
183 
184 	return (EINVAL);
185 }
186 
187 int
188 vop_enoent(struct vop_generic_args *ap)
189 {
190 
191 	return (ENOENT);
192 }
193 
194 int
195 vop_eagain(struct vop_generic_args *ap)
196 {
197 
198 	return (EAGAIN);
199 }
200 
201 int
202 vop_null(struct vop_generic_args *ap)
203 {
204 
205 	return (0);
206 }
207 
208 /*
209  * Helper function to panic on some bad VOPs in some filesystems.
210  */
211 int
212 vop_panic(struct vop_generic_args *ap)
213 {
214 
215 	panic("filesystem goof: vop_panic[%s]", ap->a_desc->vdesc_name);
216 }
217 
218 /*
219  * vop_std<something> and vop_no<something> are default functions for use by
220  * filesystems that need the "default reasonable" implementation for a
221  * particular operation.
222  *
223  * The documentation for the operations they implement exists (if it exists)
224  * in the VOP_<SOMETHING>(9) manpage (all uppercase).
225  */
226 
227 /*
228  * Default vop for filesystems that do not support name lookup
229  */
230 static int
231 vop_nolookup(struct vop_lookup_args *ap)
232 {
233 
234 	*ap->a_vpp = NULL;
235 	return (ENOTDIR);
236 }
237 
238 /*
239  * vop_norename:
240  *
241  * Handle unlock and reference counting for arguments of vop_rename
242  * for filesystems that do not implement rename operation.
243  */
244 static int
245 vop_norename(struct vop_rename_args *ap)
246 {
247 
248 	vop_rename_fail(ap);
249 	return (EOPNOTSUPP);
250 }
251 
252 /*
253  *	vop_nostrategy:
254  *
255  *	Strategy routine for VFS devices that have none.
256  *
257  *	BIO_ERROR and B_INVAL must be cleared prior to calling any strategy
258  *	routine.  Typically this is done for a BIO_READ strategy call.
259  *	Typically B_INVAL is assumed to already be clear prior to a write
260  *	and should not be cleared manually unless you just made the buffer
261  *	invalid.  BIO_ERROR should be cleared either way.
262  */
263 
264 static int
265 vop_nostrategy (struct vop_strategy_args *ap)
266 {
267 	printf("No strategy for buffer at %p\n", ap->a_bp);
268 	vn_printf(ap->a_vp, "vnode ");
269 	ap->a_bp->b_ioflags |= BIO_ERROR;
270 	ap->a_bp->b_error = EOPNOTSUPP;
271 	bufdone(ap->a_bp);
272 	return (EOPNOTSUPP);
273 }
274 
275 /*
276  * Check if a named file exists in a given directory vnode
277  *
278  * Returns 0 if the file exists, ENOENT if it doesn't, or errors returned by
279  * vn_dir_next_dirent().
280  */
281 static int
282 dirent_exists(struct vnode *vp, const char *dirname, struct thread *td)
283 {
284 	char *dirbuf;
285 	int error, eofflag;
286 	size_t dirbuflen, len;
287 	off_t off;
288 	struct dirent *dp;
289 	struct vattr va;
290 
291 	ASSERT_VOP_LOCKED(vp, "vnode not locked");
292 	KASSERT(vp->v_type == VDIR, ("vp %p is not a directory", vp));
293 
294 	error = VOP_GETATTR(vp, &va, td->td_ucred);
295 	if (error != 0)
296 		return (error);
297 
298 	dirbuflen = MAX(DEV_BSIZE, GENERIC_MAXDIRSIZ);
299 	if (dirbuflen < va.va_blocksize)
300 		dirbuflen = va.va_blocksize;
301 	dirbuf = malloc(dirbuflen, M_TEMP, M_WAITOK);
302 
303 	len = 0;
304 	off = 0;
305 	eofflag = 0;
306 
307 	for (;;) {
308 		error = vn_dir_next_dirent(vp, td, dirbuf, dirbuflen,
309 		    &dp, &len, &off, &eofflag);
310 		if (error != 0)
311 			goto out;
312 
313 		if (len == 0)
314 			break;
315 
316 		if (dp->d_type != DT_WHT && dp->d_fileno != 0 &&
317 		    strcmp(dp->d_name, dirname) == 0)
318 			goto out;
319 	}
320 
321 	error = ENOENT;
322 
323 out:
324 	free(dirbuf, M_TEMP);
325 	return (error);
326 }
327 
328 int
329 vop_stdaccess(struct vop_access_args *ap)
330 {
331 
332 	KASSERT((ap->a_accmode & ~(VEXEC | VWRITE | VREAD | VADMIN |
333 	    VAPPEND)) == 0, ("invalid bit in accmode"));
334 
335 	return (VOP_ACCESSX(ap->a_vp, ap->a_accmode, ap->a_cred, ap->a_td));
336 }
337 
338 int
339 vop_stdaccessx(struct vop_accessx_args *ap)
340 {
341 	int error;
342 	accmode_t accmode = ap->a_accmode;
343 
344 	error = vfs_unixify_accmode(&accmode);
345 	if (error != 0)
346 		return (error);
347 
348 	if (accmode == 0)
349 		return (0);
350 
351 	return (VOP_ACCESS(ap->a_vp, accmode, ap->a_cred, ap->a_td));
352 }
353 
354 /*
355  * Advisory record locking support
356  */
357 int
358 vop_stdadvlock(struct vop_advlock_args *ap)
359 {
360 	struct vnode *vp;
361 	struct mount *mp;
362 	struct vattr vattr;
363 	int error;
364 
365 	vp = ap->a_vp;
366 
367 	/*
368 	 * Provide atomicity of open(O_CREAT | O_EXCL | O_EXLOCK) for
369 	 * local filesystems.  See vn_open_cred() for reciprocal part.
370 	 */
371 	mp = vp->v_mount;
372 	if (mp != NULL && (mp->mnt_flag & MNT_LOCAL) != 0 &&
373 	    ap->a_op == F_SETLK && (ap->a_flags & F_FIRSTOPEN) == 0) {
374 		VI_LOCK(vp);
375 		while ((vp->v_iflag & VI_FOPENING) != 0)
376 			msleep(vp, VI_MTX(vp), PLOCK, "lockfo", 0);
377 		VI_UNLOCK(vp);
378 	}
379 
380 	if (ap->a_fl->l_whence == SEEK_END) {
381 		/*
382 		 * The NFSv4 server must avoid doing a vn_lock() here, since it
383 		 * can deadlock the nfsd threads, due to a LOR.  Fortunately
384 		 * the NFSv4 server always uses SEEK_SET and this code is
385 		 * only required for the SEEK_END case.
386 		 */
387 		vn_lock(vp, LK_SHARED | LK_RETRY);
388 		error = VOP_GETATTR(vp, &vattr, curthread->td_ucred);
389 		VOP_UNLOCK(vp);
390 		if (error)
391 			return (error);
392 	} else
393 		vattr.va_size = 0;
394 
395 	return (lf_advlock(ap, &(vp->v_lockf), vattr.va_size));
396 }
397 
398 int
399 vop_stdadvlockasync(struct vop_advlockasync_args *ap)
400 {
401 	struct vnode *vp;
402 	struct vattr vattr;
403 	int error;
404 
405 	vp = ap->a_vp;
406 	if (ap->a_fl->l_whence == SEEK_END) {
407 		/* The size argument is only needed for SEEK_END. */
408 		vn_lock(vp, LK_SHARED | LK_RETRY);
409 		error = VOP_GETATTR(vp, &vattr, curthread->td_ucred);
410 		VOP_UNLOCK(vp);
411 		if (error)
412 			return (error);
413 	} else
414 		vattr.va_size = 0;
415 
416 	return (lf_advlockasync(ap, &(vp->v_lockf), vattr.va_size));
417 }
418 
419 int
420 vop_stdadvlockpurge(struct vop_advlockpurge_args *ap)
421 {
422 	struct vnode *vp;
423 
424 	vp = ap->a_vp;
425 	lf_purgelocks(vp, &vp->v_lockf);
426 	return (0);
427 }
428 
429 /*
430  * vop_stdpathconf:
431  *
432  * Standard implementation of POSIX pathconf, to get information about limits
433  * for a filesystem.
434  * Override per filesystem for the case where the filesystem has smaller
435  * limits.
436  */
437 int
438 vop_stdpathconf(struct vop_pathconf_args *ap)
439 {
440 
441 	switch (ap->a_name) {
442 		case _PC_ASYNC_IO:
443 			*ap->a_retval = _POSIX_ASYNCHRONOUS_IO;
444 			return (0);
445 		case _PC_PATH_MAX:
446 			*ap->a_retval = PATH_MAX;
447 			return (0);
448 		case _PC_ACL_EXTENDED:
449 		case _PC_ACL_NFS4:
450 		case _PC_CAP_PRESENT:
451 		case _PC_DEALLOC_PRESENT:
452 		case _PC_INF_PRESENT:
453 		case _PC_MAC_PRESENT:
454 			*ap->a_retval = 0;
455 			return (0);
456 		default:
457 			return (EINVAL);
458 	}
459 	/* NOTREACHED */
460 }
461 
462 /*
463  * Standard lock, unlock and islocked functions.
464  */
465 int
466 vop_stdlock(struct vop_lock1_args *ap)
467 {
468 	struct vnode *vp = ap->a_vp;
469 	struct mtx *ilk;
470 
471 	ilk = VI_MTX(vp);
472 	return (lockmgr_lock_flags(vp->v_vnlock, ap->a_flags,
473 	    &ilk->lock_object, ap->a_file, ap->a_line));
474 }
475 
476 /* See above. */
477 int
478 vop_stdunlock(struct vop_unlock_args *ap)
479 {
480 	struct vnode *vp = ap->a_vp;
481 
482 	return (lockmgr_unlock(vp->v_vnlock));
483 }
484 
485 /* See above. */
486 int
487 vop_stdislocked(struct vop_islocked_args *ap)
488 {
489 
490 	return (lockstatus(ap->a_vp->v_vnlock));
491 }
492 
493 /*
494  * Variants of the above set.
495  *
496  * Differences are:
497  * - shared locking disablement is not supported
498  * - v_vnlock pointer is not honored
499  */
500 int
501 vop_lock(struct vop_lock1_args *ap)
502 {
503 	struct vnode *vp = ap->a_vp;
504 	int flags = ap->a_flags;
505 	struct mtx *ilk;
506 
507 	MPASS(vp->v_vnlock == &vp->v_lock);
508 
509 	if (__predict_false((flags & ~(LK_TYPE_MASK | LK_NODDLKTREAT | LK_RETRY)) != 0))
510 		goto other;
511 
512 	switch (flags & LK_TYPE_MASK) {
513 	case LK_SHARED:
514 		return (lockmgr_slock(&vp->v_lock, flags, ap->a_file, ap->a_line));
515 	case LK_EXCLUSIVE:
516 		return (lockmgr_xlock(&vp->v_lock, flags, ap->a_file, ap->a_line));
517 	}
518 other:
519 	ilk = VI_MTX(vp);
520 	return (lockmgr_lock_flags(&vp->v_lock, flags,
521 	    &ilk->lock_object, ap->a_file, ap->a_line));
522 }
523 
524 int
525 vop_unlock(struct vop_unlock_args *ap)
526 {
527 	struct vnode *vp = ap->a_vp;
528 
529 	MPASS(vp->v_vnlock == &vp->v_lock);
530 
531 	return (lockmgr_unlock(&vp->v_lock));
532 }
533 
534 int
535 vop_islocked(struct vop_islocked_args *ap)
536 {
537 	struct vnode *vp = ap->a_vp;
538 
539 	MPASS(vp->v_vnlock == &vp->v_lock);
540 
541 	return (lockstatus(&vp->v_lock));
542 }
543 
544 /*
545  * Return true for select/poll.
546  */
547 int
548 vop_nopoll(struct vop_poll_args *ap)
549 {
550 
551 	if (ap->a_events & ~POLLSTANDARD)
552 		return (POLLNVAL);
553 	return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
554 }
555 
556 /*
557  * Implement poll for local filesystems that support it.
558  */
559 int
560 vop_stdpoll(struct vop_poll_args *ap)
561 {
562 	if (ap->a_events & ~POLLSTANDARD)
563 		return (vn_pollrecord(ap->a_vp, ap->a_td, ap->a_events));
564 	return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
565 }
566 
567 /*
568  * Return our mount point, as we will take charge of the writes.
569  */
570 int
571 vop_stdgetwritemount(struct vop_getwritemount_args *ap)
572 {
573 	struct mount *mp;
574 	struct vnode *vp;
575 
576 	/*
577 	 * Note that having a reference does not prevent forced unmount from
578 	 * setting ->v_mount to NULL after the lock gets released. This is of
579 	 * no consequence for typical consumers (most notably vn_start_write)
580 	 * since in this case the vnode is VIRF_DOOMED. Unmount might have
581 	 * progressed far enough that its completion is only delayed by the
582 	 * reference obtained here. The consumer only needs to concern itself
583 	 * with releasing it.
584 	 */
585 	vp = ap->a_vp;
586 	mp = vfs_ref_from_vp(vp);
587 	*(ap->a_mpp) = mp;
588 	return (0);
589 }
590 
591 /*
592  * If the file system doesn't implement VOP_BMAP, then return sensible defaults:
593  * - Return the vnode's bufobj instead of any underlying device's bufobj
594  * - Calculate the physical block number as if there were equal size
595  *   consecutive blocks, but
596  * - Report no contiguous runs of blocks.
597  */
598 int
599 vop_stdbmap(struct vop_bmap_args *ap)
600 {
601 
602 	if (ap->a_bop != NULL)
603 		*ap->a_bop = &ap->a_vp->v_bufobj;
604 	if (ap->a_bnp != NULL)
605 		*ap->a_bnp = ap->a_bn * btodb(ap->a_vp->v_mount->mnt_stat.f_iosize);
606 	if (ap->a_runp != NULL)
607 		*ap->a_runp = 0;
608 	if (ap->a_runb != NULL)
609 		*ap->a_runb = 0;
610 	return (0);
611 }
612 
613 int
614 vop_stdfsync(struct vop_fsync_args *ap)
615 {
616 
617 	return (vn_fsync_buf(ap->a_vp, ap->a_waitfor));
618 }
619 
620 static int
621 vop_stdfdatasync(struct vop_fdatasync_args *ap)
622 {
623 
624 	return (VOP_FSYNC(ap->a_vp, MNT_WAIT, ap->a_td));
625 }
626 
627 int
628 vop_stdfdatasync_buf(struct vop_fdatasync_args *ap)
629 {
630 
631 	return (vn_fsync_buf(ap->a_vp, MNT_WAIT));
632 }
633 
634 /* XXX Needs good comment and more info in the manpage (VOP_GETPAGES(9)). */
635 int
636 vop_stdgetpages(struct vop_getpages_args *ap)
637 {
638 
639 	return vnode_pager_generic_getpages(ap->a_vp, ap->a_m,
640 	    ap->a_count, ap->a_rbehind, ap->a_rahead, NULL, NULL);
641 }
642 
643 static int
644 vop_stdgetpages_async(struct vop_getpages_async_args *ap)
645 {
646 	int error;
647 
648 	error = VOP_GETPAGES(ap->a_vp, ap->a_m, ap->a_count, ap->a_rbehind,
649 	    ap->a_rahead);
650 	if (ap->a_iodone != NULL)
651 		ap->a_iodone(ap->a_arg, ap->a_m, ap->a_count, error);
652 	return (error);
653 }
654 
655 int
656 vop_stdkqfilter(struct vop_kqfilter_args *ap)
657 {
658 	return vfs_kqfilter(ap);
659 }
660 
661 /* XXX Needs good comment and more info in the manpage (VOP_PUTPAGES(9)). */
662 int
663 vop_stdputpages(struct vop_putpages_args *ap)
664 {
665 
666 	return vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count,
667 	     ap->a_sync, ap->a_rtvals);
668 }
669 
670 int
671 vop_stdvptofh(struct vop_vptofh_args *ap)
672 {
673 	return (EOPNOTSUPP);
674 }
675 
676 int
677 vop_stdvptocnp(struct vop_vptocnp_args *ap)
678 {
679 	struct vnode *const vp = ap->a_vp;
680 	struct vnode **const dvp = ap->a_vpp;
681 	char *buf = ap->a_buf;
682 	size_t *buflen = ap->a_buflen;
683 	char *dirbuf;
684 	int i = *buflen;
685 	int error = 0, covered = 0;
686 	int eofflag, flags, locked;
687 	size_t dirbuflen, len;
688 	off_t off;
689 	ino_t fileno;
690 	struct vattr va;
691 	struct nameidata nd;
692 	struct thread *const td = curthread;
693 	struct ucred *const cred = td->td_ucred;
694 	struct dirent *dp;
695 	struct vnode *mvp;
696 
697 	if (vp->v_type != VDIR)
698 		return (ENOENT);
699 
700 	error = VOP_GETATTR(vp, &va, cred);
701 	if (error)
702 		return (error);
703 
704 	VREF(vp);
705 	locked = VOP_ISLOCKED(vp);
706 	VOP_UNLOCK(vp);
707 	NDINIT_ATVP(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF, UIO_SYSSPACE,
708 	    "..", vp);
709 	flags = FREAD;
710 	error = vn_open_cred(&nd, &flags, 0, VN_OPEN_NOAUDIT, cred, NULL);
711 	if (error) {
712 		vn_lock(vp, locked | LK_RETRY);
713 		return (error);
714 	}
715 	NDFREE_PNBUF(&nd);
716 
717 	mvp = *dvp = nd.ni_vp;
718 
719 	if (vp->v_mount != (*dvp)->v_mount &&
720 	    ((*dvp)->v_vflag & VV_ROOT) &&
721 	    ((*dvp)->v_mount->mnt_flag & MNT_UNION)) {
722 		*dvp = (*dvp)->v_mount->mnt_vnodecovered;
723 		VREF(mvp);
724 		VOP_UNLOCK(mvp);
725 		vn_close(mvp, FREAD, cred, td);
726 		VREF(*dvp);
727 		vn_lock(*dvp, LK_SHARED | LK_RETRY);
728 		covered = 1;
729 	}
730 
731 	fileno = va.va_fileid;
732 
733 	dirbuflen = MAX(DEV_BSIZE, GENERIC_MAXDIRSIZ);
734 	if (dirbuflen < va.va_blocksize)
735 		dirbuflen = va.va_blocksize;
736 	dirbuf = malloc(dirbuflen, M_TEMP, M_WAITOK);
737 
738 	if ((*dvp)->v_type != VDIR) {
739 		error = ENOENT;
740 		goto out;
741 	}
742 
743 	len = 0;
744 	off = 0;
745 	eofflag = 0;
746 
747 	for (;;) {
748 		/* call VOP_READDIR of parent */
749 		error = vn_dir_next_dirent(*dvp, td,
750 		    dirbuf, dirbuflen, &dp, &len, &off, &eofflag);
751 		if (error != 0)
752 			goto out;
753 
754 		if (len == 0) {
755 			error = ENOENT;
756 			goto out;
757 		}
758 
759 		if ((dp->d_type != DT_WHT) &&
760 		    (dp->d_fileno == fileno)) {
761 			if (covered) {
762 				VOP_UNLOCK(*dvp);
763 				vn_lock(mvp, LK_SHARED | LK_RETRY);
764 				if (dirent_exists(mvp, dp->d_name, td) == 0) {
765 					error = ENOENT;
766 					VOP_UNLOCK(mvp);
767 					vn_lock(*dvp, LK_SHARED | LK_RETRY);
768 					goto out;
769 				}
770 				VOP_UNLOCK(mvp);
771 				vn_lock(*dvp, LK_SHARED | LK_RETRY);
772 			}
773 			i -= dp->d_namlen;
774 
775 			if (i < 0) {
776 				error = ENOMEM;
777 				goto out;
778 			}
779 			if (dp->d_namlen == 1 && dp->d_name[0] == '.') {
780 				error = ENOENT;
781 			} else {
782 				bcopy(dp->d_name, buf + i, dp->d_namlen);
783 				error = 0;
784 			}
785 			goto out;
786 		}
787 	}
788 
789 out:
790 	free(dirbuf, M_TEMP);
791 	if (!error) {
792 		*buflen = i;
793 		vref(*dvp);
794 	}
795 	if (covered) {
796 		vput(*dvp);
797 		vrele(mvp);
798 	} else {
799 		VOP_UNLOCK(mvp);
800 		vn_close(mvp, FREAD, cred, td);
801 	}
802 	vn_lock(vp, locked | LK_RETRY);
803 	return (error);
804 }
805 
806 int
807 vop_stdallocate(struct vop_allocate_args *ap)
808 {
809 #ifdef __notyet__
810 	struct statfs *sfs;
811 	off_t maxfilesize = 0;
812 #endif
813 	struct iovec aiov;
814 	struct vattr vattr, *vap;
815 	struct uio auio;
816 	off_t fsize, len, cur, offset;
817 	uint8_t *buf;
818 	struct thread *td;
819 	struct vnode *vp;
820 	size_t iosize;
821 	int error;
822 
823 	buf = NULL;
824 	error = 0;
825 	td = curthread;
826 	vap = &vattr;
827 	vp = ap->a_vp;
828 	len = *ap->a_len;
829 	offset = *ap->a_offset;
830 
831 	error = VOP_GETATTR(vp, vap, ap->a_cred);
832 	if (error != 0)
833 		goto out;
834 	fsize = vap->va_size;
835 	iosize = vap->va_blocksize;
836 	if (iosize == 0)
837 		iosize = BLKDEV_IOSIZE;
838 	if (iosize > maxphys)
839 		iosize = maxphys;
840 	buf = malloc(iosize, M_TEMP, M_WAITOK);
841 
842 #ifdef __notyet__
843 	/*
844 	 * Check if the filesystem sets f_maxfilesize; if not use
845 	 * VOP_SETATTR to perform the check.
846 	 */
847 	sfs = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK);
848 	error = VFS_STATFS(vp->v_mount, sfs, td);
849 	if (error == 0)
850 		maxfilesize = sfs->f_maxfilesize;
851 	free(sfs, M_STATFS);
852 	if (error != 0)
853 		goto out;
854 	if (maxfilesize) {
855 		if (offset > maxfilesize || len > maxfilesize ||
856 		    offset + len > maxfilesize) {
857 			error = EFBIG;
858 			goto out;
859 		}
860 	} else
861 #endif
862 	if (offset + len > vap->va_size) {
863 		/*
864 		 * Test offset + len against the filesystem's maxfilesize.
865 		 */
866 		VATTR_NULL(vap);
867 		vap->va_size = offset + len;
868 		error = VOP_SETATTR(vp, vap, ap->a_cred);
869 		if (error != 0)
870 			goto out;
871 		VATTR_NULL(vap);
872 		vap->va_size = fsize;
873 		error = VOP_SETATTR(vp, vap, ap->a_cred);
874 		if (error != 0)
875 			goto out;
876 	}
877 
878 	for (;;) {
879 		/*
880 		 * Read and write back anything below the nominal file
881 		 * size.  There's currently no way outside the filesystem
882 		 * to know whether this area is sparse or not.
883 		 */
884 		cur = iosize;
885 		if ((offset % iosize) != 0)
886 			cur -= (offset % iosize);
887 		if (cur > len)
888 			cur = len;
889 		if (offset < fsize) {
890 			aiov.iov_base = buf;
891 			aiov.iov_len = cur;
892 			auio.uio_iov = &aiov;
893 			auio.uio_iovcnt = 1;
894 			auio.uio_offset = offset;
895 			auio.uio_resid = cur;
896 			auio.uio_segflg = UIO_SYSSPACE;
897 			auio.uio_rw = UIO_READ;
898 			auio.uio_td = td;
899 			error = VOP_READ(vp, &auio, ap->a_ioflag, ap->a_cred);
900 			if (error != 0)
901 				break;
902 			if (auio.uio_resid > 0) {
903 				bzero(buf + cur - auio.uio_resid,
904 				    auio.uio_resid);
905 			}
906 		} else {
907 			bzero(buf, cur);
908 		}
909 
910 		aiov.iov_base = buf;
911 		aiov.iov_len = cur;
912 		auio.uio_iov = &aiov;
913 		auio.uio_iovcnt = 1;
914 		auio.uio_offset = offset;
915 		auio.uio_resid = cur;
916 		auio.uio_segflg = UIO_SYSSPACE;
917 		auio.uio_rw = UIO_WRITE;
918 		auio.uio_td = td;
919 
920 		error = VOP_WRITE(vp, &auio, ap->a_ioflag, ap->a_cred);
921 		if (error != 0)
922 			break;
923 
924 		len -= cur;
925 		offset += cur;
926 		if (len == 0)
927 			break;
928 		if (should_yield())
929 			break;
930 	}
931 
932  out:
933 	*ap->a_len = len;
934 	*ap->a_offset = offset;
935 	free(buf, M_TEMP);
936 	return (error);
937 }
938 
939 static int
940 vp_zerofill(struct vnode *vp, struct vattr *vap, off_t *offsetp, off_t *lenp,
941     int ioflag, struct ucred *cred)
942 {
943 	int iosize;
944 	int error = 0;
945 	struct iovec aiov;
946 	struct uio auio;
947 	struct thread *td;
948 	off_t offset, len;
949 
950 	iosize = vap->va_blocksize;
951 	td = curthread;
952 	offset = *offsetp;
953 	len = *lenp;
954 
955 	if (iosize == 0)
956 		iosize = BLKDEV_IOSIZE;
957 	/* If va_blocksize is 512 bytes, iosize will be 4 kilobytes */
958 	iosize = min(iosize * 8, ZERO_REGION_SIZE);
959 
960 	while (len > 0) {
961 		int xfersize = iosize;
962 		if (offset % iosize != 0)
963 			xfersize -= offset % iosize;
964 		if (xfersize > len)
965 			xfersize = len;
966 
967 		aiov.iov_base = __DECONST(void *, zero_region);
968 		aiov.iov_len = xfersize;
969 		auio.uio_iov = &aiov;
970 		auio.uio_iovcnt = 1;
971 		auio.uio_offset = offset;
972 		auio.uio_resid = xfersize;
973 		auio.uio_segflg = UIO_SYSSPACE;
974 		auio.uio_rw = UIO_WRITE;
975 		auio.uio_td = td;
976 
977 		error = VOP_WRITE(vp, &auio, ioflag, cred);
978 		if (error != 0) {
979 			len -= xfersize - auio.uio_resid;
980 			offset += xfersize - auio.uio_resid;
981 			break;
982 		}
983 
984 		len -= xfersize;
985 		offset += xfersize;
986 	}
987 
988 	*offsetp = offset;
989 	*lenp = len;
990 	return (error);
991 }
992 
993 int
994 vop_stddeallocate(struct vop_deallocate_args *ap)
995 {
996 	struct vnode *vp;
997 	off_t offset, len;
998 	struct ucred *cred;
999 	int error;
1000 	struct vattr va;
1001 	off_t noff, xfersize, rem;
1002 
1003 	vp = ap->a_vp;
1004 	offset = *ap->a_offset;
1005 	cred = ap->a_cred;
1006 
1007 	error = VOP_GETATTR(vp, &va, cred);
1008 	if (error)
1009 		return (error);
1010 
1011 	len = omin((off_t)va.va_size - offset, *ap->a_len);
1012 	while (len > 0) {
1013 		noff = offset;
1014 		error = vn_bmap_seekhole_locked(vp, FIOSEEKDATA, &noff, cred);
1015 		if (error) {
1016 			if (error != ENXIO)
1017 				/* XXX: Is it okay to fallback further? */
1018 				goto out;
1019 
1020 			/*
1021 			 * No more data region to be filled
1022 			 */
1023 			offset += len;
1024 			len = 0;
1025 			error = 0;
1026 			break;
1027 		}
1028 		KASSERT(noff >= offset, ("FIOSEEKDATA going backward"));
1029 		if (noff != offset) {
1030 			xfersize = omin(noff - offset, len);
1031 			len -= xfersize;
1032 			offset += xfersize;
1033 			if (len == 0)
1034 				break;
1035 		}
1036 		error = vn_bmap_seekhole_locked(vp, FIOSEEKHOLE, &noff, cred);
1037 		if (error)
1038 			goto out;
1039 
1040 		/* Fill zeroes */
1041 		xfersize = rem = omin(noff - offset, len);
1042 		error = vp_zerofill(vp, &va, &offset, &rem, ap->a_ioflag, cred);
1043 		if (error) {
1044 			len -= xfersize - rem;
1045 			goto out;
1046 		}
1047 
1048 		len -= xfersize;
1049 		if (should_yield())
1050 			break;
1051 	}
1052 	/* Handle the case when offset is beyond EOF */
1053 	if (len < 0)
1054 		len = 0;
1055 out:
1056 	*ap->a_offset = offset;
1057 	*ap->a_len = len;
1058 	return (error);
1059 }
1060 
1061 int
1062 vop_stdadvise(struct vop_advise_args *ap)
1063 {
1064 	struct vnode *vp;
1065 	struct bufobj *bo;
1066 	daddr_t startn, endn;
1067 	off_t bstart, bend, start, end;
1068 	int bsize, error;
1069 
1070 	vp = ap->a_vp;
1071 	switch (ap->a_advice) {
1072 	case POSIX_FADV_WILLNEED:
1073 		/*
1074 		 * Do nothing for now.  Filesystems should provide a
1075 		 * custom method which starts an asynchronous read of
1076 		 * the requested region.
1077 		 */
1078 		error = 0;
1079 		break;
1080 	case POSIX_FADV_DONTNEED:
1081 		error = 0;
1082 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1083 		if (VN_IS_DOOMED(vp)) {
1084 			VOP_UNLOCK(vp);
1085 			break;
1086 		}
1087 
1088 		/*
1089 		 * Round to block boundaries (and later possibly further to
1090 		 * page boundaries).  Applications cannot reasonably be aware
1091 		 * of the boundaries, and the rounding must be to expand at
1092 		 * both extremities to cover enough.  It still doesn't cover
1093 		 * read-ahead.  For partial blocks, this gives unnecessary
1094 		 * discarding of buffers but is efficient enough since the
1095 		 * pages usually remain in VMIO for some time.
1096 		 */
1097 		bsize = vp->v_bufobj.bo_bsize;
1098 		bstart = rounddown(ap->a_start, bsize);
1099 		bend = roundup(ap->a_end, bsize);
1100 
1101 		/*
1102 		 * Deactivate pages in the specified range from the backing VM
1103 		 * object.  Pages that are resident in the buffer cache will
1104 		 * remain wired until their corresponding buffers are released
1105 		 * below.
1106 		 */
1107 		if (vp->v_object != NULL) {
1108 			start = trunc_page(bstart);
1109 			end = round_page(bend);
1110 			VM_OBJECT_RLOCK(vp->v_object);
1111 			vm_object_page_noreuse(vp->v_object, OFF_TO_IDX(start),
1112 			    OFF_TO_IDX(end));
1113 			VM_OBJECT_RUNLOCK(vp->v_object);
1114 		}
1115 
1116 		bo = &vp->v_bufobj;
1117 		BO_RLOCK(bo);
1118 		startn = bstart / bsize;
1119 		endn = bend / bsize;
1120 		error = bnoreuselist(&bo->bo_clean, bo, startn, endn);
1121 		if (error == 0)
1122 			error = bnoreuselist(&bo->bo_dirty, bo, startn, endn);
1123 		BO_RUNLOCK(bo);
1124 		VOP_UNLOCK(vp);
1125 		break;
1126 	default:
1127 		error = EINVAL;
1128 		break;
1129 	}
1130 	return (error);
1131 }
1132 
1133 int
1134 vop_stdunp_bind(struct vop_unp_bind_args *ap)
1135 {
1136 
1137 	ap->a_vp->v_unpcb = ap->a_unpcb;
1138 	return (0);
1139 }
1140 
1141 int
1142 vop_stdunp_connect(struct vop_unp_connect_args *ap)
1143 {
1144 
1145 	*ap->a_unpcb = ap->a_vp->v_unpcb;
1146 	return (0);
1147 }
1148 
1149 int
1150 vop_stdunp_detach(struct vop_unp_detach_args *ap)
1151 {
1152 
1153 	ap->a_vp->v_unpcb = NULL;
1154 	return (0);
1155 }
1156 
1157 static int
1158 vop_stdis_text(struct vop_is_text_args *ap)
1159 {
1160 
1161 	return (atomic_load_int(&ap->a_vp->v_writecount) < 0);
1162 }
1163 
1164 int
1165 vop_stdset_text(struct vop_set_text_args *ap)
1166 {
1167 	struct vnode *vp;
1168 	int n;
1169 	bool gotref;
1170 
1171 	vp = ap->a_vp;
1172 
1173 	n = atomic_load_int(&vp->v_writecount);
1174 	for (;;) {
1175 		if (__predict_false(n > 0)) {
1176 			return (ETXTBSY);
1177 		}
1178 
1179 		/*
1180 		 * Transition point, we may need to grab a reference on the vnode.
1181 		 *
1182 		 * Take the ref early As a safety measure against bogus calls
1183 		 * to vop_stdunset_text.
1184 		 */
1185 		if (n == 0) {
1186 			gotref = false;
1187 			if ((vn_irflag_read(vp) & VIRF_TEXT_REF) != 0) {
1188 				vref(vp);
1189 				gotref = true;
1190 			}
1191 			if (atomic_fcmpset_int(&vp->v_writecount, &n, -1)) {
1192 				return (0);
1193 			}
1194 			if (gotref) {
1195 				vunref(vp);
1196 			}
1197 			continue;
1198 		}
1199 
1200 		MPASS(n < 0);
1201 		if (atomic_fcmpset_int(&vp->v_writecount, &n, n - 1)) {
1202 			return (0);
1203 		}
1204 	}
1205 	__assert_unreachable();
1206 }
1207 
1208 static int
1209 vop_stdunset_text(struct vop_unset_text_args *ap)
1210 {
1211 	struct vnode *vp;
1212 	int n;
1213 
1214 	vp = ap->a_vp;
1215 
1216 	n = atomic_load_int(&vp->v_writecount);
1217 	for (;;) {
1218 		if (__predict_false(n >= 0)) {
1219 			return (EINVAL);
1220 		}
1221 
1222 		/*
1223 		 * Transition point, we may need to release a reference on the vnode.
1224 		 */
1225 		if (n == -1) {
1226 			if (atomic_fcmpset_int(&vp->v_writecount, &n, 0)) {
1227 				if ((vn_irflag_read(vp) & VIRF_TEXT_REF) != 0) {
1228 					vunref(vp);
1229 				}
1230 				return (0);
1231 			}
1232 			continue;
1233 		}
1234 
1235 		MPASS(n < -1);
1236 		if (atomic_fcmpset_int(&vp->v_writecount, &n, n + 1)) {
1237 			return (0);
1238 		}
1239 	}
1240 	__assert_unreachable();
1241 }
1242 
1243 static int __always_inline
1244 vop_stdadd_writecount_impl(struct vop_add_writecount_args *ap, bool handle_msync)
1245 {
1246 	struct vnode *vp;
1247 	struct mount *mp __diagused;
1248 	int n;
1249 
1250 	vp = ap->a_vp;
1251 
1252 #ifdef INVARIANTS
1253 	mp = vp->v_mount;
1254 	if (mp != NULL) {
1255 		if (handle_msync) {
1256 			VNPASS((mp->mnt_kern_flag & MNTK_NOMSYNC) == 0, vp);
1257 		} else {
1258 			VNPASS((mp->mnt_kern_flag & MNTK_NOMSYNC) != 0, vp);
1259 		}
1260 	}
1261 #endif
1262 
1263 	n = atomic_load_int(&vp->v_writecount);
1264 	for (;;) {
1265 		if (__predict_false(n < 0)) {
1266 			return (ETXTBSY);
1267 		}
1268 
1269 		VNASSERT(n + ap->a_inc >= 0, vp,
1270 		    ("neg writecount increment %d + %d = %d", n, ap->a_inc,
1271 		    n + ap->a_inc));
1272 		if (n == 0) {
1273 			if (handle_msync) {
1274 				vlazy(vp);
1275 			}
1276 		}
1277 
1278 		if (atomic_fcmpset_int(&vp->v_writecount, &n, n + ap->a_inc)) {
1279 			return (0);
1280 		}
1281 	}
1282 	__assert_unreachable();
1283 }
1284 
1285 int
1286 vop_stdadd_writecount(struct vop_add_writecount_args *ap)
1287 {
1288 
1289 	return (vop_stdadd_writecount_impl(ap, true));
1290 }
1291 
1292 int
1293 vop_stdadd_writecount_nomsync(struct vop_add_writecount_args *ap)
1294 {
1295 
1296 	return (vop_stdadd_writecount_impl(ap, false));
1297 }
1298 
1299 int
1300 vop_stdneed_inactive(struct vop_need_inactive_args *ap)
1301 {
1302 
1303 	return (1);
1304 }
1305 
1306 int
1307 vop_stdioctl(struct vop_ioctl_args *ap)
1308 {
1309 	struct vnode *vp;
1310 	struct vattr va;
1311 	off_t *offp;
1312 	int error;
1313 
1314 	switch (ap->a_command) {
1315 	case FIOSEEKDATA:
1316 	case FIOSEEKHOLE:
1317 		vp = ap->a_vp;
1318 		error = vn_lock(vp, LK_SHARED);
1319 		if (error != 0)
1320 			return (EBADF);
1321 		if (vp->v_type == VREG)
1322 			error = VOP_GETATTR(vp, &va, ap->a_cred);
1323 		else
1324 			error = ENOTTY;
1325 		if (error == 0) {
1326 			offp = ap->a_data;
1327 			if (*offp < 0 || *offp >= va.va_size)
1328 				error = ENXIO;
1329 			else if (ap->a_command == FIOSEEKHOLE)
1330 				*offp = va.va_size;
1331 		}
1332 		VOP_UNLOCK(vp);
1333 		break;
1334 	default:
1335 		error = ENOTTY;
1336 		break;
1337 	}
1338 	return (error);
1339 }
1340 
1341 /*
1342  * vfs default ops
1343  * used to fill the vfs function table to get reasonable default return values.
1344  */
1345 int
1346 vfs_stdroot(struct mount *mp, int flags, struct vnode **vpp)
1347 {
1348 
1349 	return (EOPNOTSUPP);
1350 }
1351 
1352 int
1353 vfs_stdstatfs(struct mount *mp, struct statfs *sbp)
1354 {
1355 
1356 	return (EOPNOTSUPP);
1357 }
1358 
1359 int
1360 vfs_stdquotactl(struct mount *mp, int cmds, uid_t uid, void *arg, bool *mp_busy)
1361 {
1362 	return (EOPNOTSUPP);
1363 }
1364 
1365 int
1366 vfs_stdsync(struct mount *mp, int waitfor)
1367 {
1368 	struct vnode *vp, *mvp;
1369 	struct thread *td;
1370 	int error, lockreq, allerror = 0;
1371 
1372 	td = curthread;
1373 	lockreq = LK_EXCLUSIVE | LK_INTERLOCK;
1374 	if (waitfor != MNT_WAIT)
1375 		lockreq |= LK_NOWAIT;
1376 	/*
1377 	 * Force stale buffer cache information to be flushed.
1378 	 */
1379 loop:
1380 	MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
1381 		if (vp->v_bufobj.bo_dirty.bv_cnt == 0) {
1382 			VI_UNLOCK(vp);
1383 			continue;
1384 		}
1385 		if ((error = vget(vp, lockreq)) != 0) {
1386 			if (error == ENOENT) {
1387 				MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
1388 				goto loop;
1389 			}
1390 			continue;
1391 		}
1392 		error = VOP_FSYNC(vp, waitfor, td);
1393 		if (error)
1394 			allerror = error;
1395 		vput(vp);
1396 	}
1397 	return (allerror);
1398 }
1399 
1400 int
1401 vfs_stdnosync(struct mount *mp, int waitfor)
1402 {
1403 
1404 	return (0);
1405 }
1406 
1407 static int
1408 vop_stdcopy_file_range(struct vop_copy_file_range_args *ap)
1409 {
1410 	int error;
1411 
1412 	error = vn_generic_copy_file_range(ap->a_invp, ap->a_inoffp,
1413 	    ap->a_outvp, ap->a_outoffp, ap->a_lenp, ap->a_flags, ap->a_incred,
1414 	    ap->a_outcred, ap->a_fsizetd);
1415 	return (error);
1416 }
1417 
1418 int
1419 vfs_stdvget(struct mount *mp, ino_t ino, int flags, struct vnode **vpp)
1420 {
1421 
1422 	return (EOPNOTSUPP);
1423 }
1424 
1425 int
1426 vfs_stdfhtovp(struct mount *mp, struct fid *fhp, int flags, struct vnode **vpp)
1427 {
1428 
1429 	return (EOPNOTSUPP);
1430 }
1431 
1432 int
1433 vfs_stdinit(struct vfsconf *vfsp)
1434 {
1435 
1436 	return (0);
1437 }
1438 
1439 int
1440 vfs_stduninit(struct vfsconf *vfsp)
1441 {
1442 
1443 	return(0);
1444 }
1445 
1446 int
1447 vfs_stdextattrctl(struct mount *mp, int cmd, struct vnode *filename_vp,
1448     int attrnamespace, const char *attrname)
1449 {
1450 
1451 	if (filename_vp != NULL)
1452 		VOP_UNLOCK(filename_vp);
1453 	return (EOPNOTSUPP);
1454 }
1455 
1456 int
1457 vfs_stdsysctl(struct mount *mp, fsctlop_t op, struct sysctl_req *req)
1458 {
1459 
1460 	return (EOPNOTSUPP);
1461 }
1462 
1463 static vop_bypass_t *
1464 bp_by_off(struct vop_vector *vop, struct vop_generic_args *a)
1465 {
1466 
1467 	return (*(vop_bypass_t **)((char *)vop + a->a_desc->vdesc_vop_offset));
1468 }
1469 
1470 int
1471 vop_sigdefer(struct vop_vector *vop, struct vop_generic_args *a)
1472 {
1473 	vop_bypass_t *bp;
1474 	int prev_stops, rc;
1475 
1476 	bp = bp_by_off(vop, a);
1477 	MPASS(bp != NULL);
1478 
1479 	prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
1480 	rc = bp(a);
1481 	sigallowstop(prev_stops);
1482 	return (rc);
1483 }
1484 
1485 static int
1486 vop_stdstat(struct vop_stat_args *a)
1487 {
1488 	struct vattr vattr;
1489 	struct vattr *vap;
1490 	struct vnode *vp;
1491 	struct stat *sb;
1492 	int error;
1493 	u_short mode;
1494 
1495 	vp = a->a_vp;
1496 	sb = a->a_sb;
1497 
1498 	error = vop_stat_helper_pre(a);
1499 	if (error != 0)
1500 		return (error);
1501 
1502 	vap = &vattr;
1503 
1504 	/*
1505 	 * Initialize defaults for new and unusual fields, so that file
1506 	 * systems which don't support these fields don't need to know
1507 	 * about them.
1508 	 */
1509 	vap->va_birthtime.tv_sec = -1;
1510 	vap->va_birthtime.tv_nsec = 0;
1511 	vap->va_fsid = VNOVAL;
1512 	vap->va_gen = 0;
1513 	vap->va_rdev = NODEV;
1514 
1515 	error = VOP_GETATTR(vp, vap, a->a_active_cred);
1516 	if (error)
1517 		goto out;
1518 
1519 	/*
1520 	 * Zero the spare stat fields
1521 	 */
1522 	bzero(sb, sizeof *sb);
1523 
1524 	/*
1525 	 * Copy from vattr table
1526 	 */
1527 	if (vap->va_fsid != VNOVAL)
1528 		sb->st_dev = vap->va_fsid;
1529 	else
1530 		sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0];
1531 	sb->st_ino = vap->va_fileid;
1532 	mode = vap->va_mode;
1533 	switch (vap->va_type) {
1534 	case VREG:
1535 		mode |= S_IFREG;
1536 		break;
1537 	case VDIR:
1538 		mode |= S_IFDIR;
1539 		break;
1540 	case VBLK:
1541 		mode |= S_IFBLK;
1542 		break;
1543 	case VCHR:
1544 		mode |= S_IFCHR;
1545 		break;
1546 	case VLNK:
1547 		mode |= S_IFLNK;
1548 		break;
1549 	case VSOCK:
1550 		mode |= S_IFSOCK;
1551 		break;
1552 	case VFIFO:
1553 		mode |= S_IFIFO;
1554 		break;
1555 	default:
1556 		error = EBADF;
1557 		goto out;
1558 	}
1559 	sb->st_mode = mode;
1560 	sb->st_nlink = vap->va_nlink;
1561 	sb->st_uid = vap->va_uid;
1562 	sb->st_gid = vap->va_gid;
1563 	sb->st_rdev = vap->va_rdev;
1564 	if (vap->va_size > OFF_MAX) {
1565 		error = EOVERFLOW;
1566 		goto out;
1567 	}
1568 	sb->st_size = vap->va_size;
1569 	sb->st_atim.tv_sec = vap->va_atime.tv_sec;
1570 	sb->st_atim.tv_nsec = vap->va_atime.tv_nsec;
1571 	sb->st_mtim.tv_sec = vap->va_mtime.tv_sec;
1572 	sb->st_mtim.tv_nsec = vap->va_mtime.tv_nsec;
1573 	sb->st_ctim.tv_sec = vap->va_ctime.tv_sec;
1574 	sb->st_ctim.tv_nsec = vap->va_ctime.tv_nsec;
1575 	sb->st_birthtim.tv_sec = vap->va_birthtime.tv_sec;
1576 	sb->st_birthtim.tv_nsec = vap->va_birthtime.tv_nsec;
1577 
1578 	/*
1579 	 * According to www.opengroup.org, the meaning of st_blksize is
1580 	 *   "a filesystem-specific preferred I/O block size for this
1581 	 *    object.  In some filesystem types, this may vary from file
1582 	 *    to file"
1583 	 * Use minimum/default of PAGE_SIZE (e.g. for VCHR).
1584 	 */
1585 
1586 	sb->st_blksize = max(PAGE_SIZE, vap->va_blocksize);
1587 	sb->st_flags = vap->va_flags;
1588 	sb->st_blocks = vap->va_bytes / S_BLKSIZE;
1589 	sb->st_gen = vap->va_gen;
1590 out:
1591 	return (vop_stat_helper_post(a, error));
1592 }
1593 
1594 static int
1595 vop_stdread_pgcache(struct vop_read_pgcache_args *ap __unused)
1596 {
1597 	return (EJUSTRETURN);
1598 }
1599 
1600 static int
1601 vop_stdvput_pair(struct vop_vput_pair_args *ap)
1602 {
1603 	struct vnode *dvp, *vp, **vpp;
1604 
1605 	dvp = ap->a_dvp;
1606 	vpp = ap->a_vpp;
1607 	vput(dvp);
1608 	if (vpp != NULL && ap->a_unlock_vp && (vp = *vpp) != NULL)
1609 		vput(vp);
1610 	return (0);
1611 }
1612 
1613 static int
1614 vop_stdgetlowvnode(struct vop_getlowvnode_args *ap)
1615 {
1616 	vref(ap->a_vp);
1617 	*ap->a_vplp = ap->a_vp;
1618 	return (0);
1619 }
1620