xref: /freebsd/sys/kern/vfs_default.c (revision a2f733abcff64628b7771a47089628b7327a88bd)
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/cdefs.h>
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/bio.h>
39 #include <sys/buf.h>
40 #include <sys/conf.h>
41 #include <sys/event.h>
42 #include <sys/filio.h>
43 #include <sys/kernel.h>
44 #include <sys/limits.h>
45 #include <sys/lock.h>
46 #include <sys/lockf.h>
47 #include <sys/malloc.h>
48 #include <sys/mount.h>
49 #include <sys/namei.h>
50 #include <sys/rwlock.h>
51 #include <sys/fcntl.h>
52 #include <sys/unistd.h>
53 #include <sys/vnode.h>
54 #include <sys/dirent.h>
55 #include <sys/poll.h>
56 #include <sys/stat.h>
57 #include <security/audit/audit.h>
58 #include <sys/priv.h>
59 
60 #include <security/mac/mac_framework.h>
61 
62 #include <vm/vm.h>
63 #include <vm/vm_object.h>
64 #include <vm/vm_extern.h>
65 #include <vm/pmap.h>
66 #include <vm/vm_map.h>
67 #include <vm/vm_page.h>
68 #include <vm/vm_pager.h>
69 #include <vm/vnode_pager.h>
70 
71 static int	vop_nolookup(struct vop_lookup_args *);
72 static int	vop_norename(struct vop_rename_args *);
73 static int	vop_nostrategy(struct vop_strategy_args *);
74 static int	dirent_exists(struct vnode *vp, const char *dirname,
75 			      struct thread *td);
76 
77 static int vop_stdis_text(struct vop_is_text_args *ap);
78 static int vop_stdunset_text(struct vop_unset_text_args *ap);
79 static int vop_stdadd_writecount(struct vop_add_writecount_args *ap);
80 static int vop_stdcopy_file_range(struct vop_copy_file_range_args *ap);
81 static int vop_stdfdatasync(struct vop_fdatasync_args *ap);
82 static int vop_stdgetpages_async(struct vop_getpages_async_args *ap);
83 static int vop_stdread_pgcache(struct vop_read_pgcache_args *ap);
84 static int vop_stdstat(struct vop_stat_args *ap);
85 static int vop_stdvput_pair(struct vop_vput_pair_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_getpages =		vop_stdgetpages,
117 	.vop_getpages_async =	vop_stdgetpages_async,
118 	.vop_getwritemount = 	vop_stdgetwritemount,
119 	.vop_inactive =		VOP_NULL,
120 	.vop_need_inactive =	vop_stdneed_inactive,
121 	.vop_ioctl =		vop_stdioctl,
122 	.vop_kqfilter =		vop_stdkqfilter,
123 	.vop_islocked =		vop_stdislocked,
124 	.vop_lock1 =		vop_stdlock,
125 	.vop_lookup =		vop_nolookup,
126 	.vop_open =		VOP_NULL,
127 	.vop_pathconf =		VOP_EINVAL,
128 	.vop_poll =		vop_nopoll,
129 	.vop_putpages =		vop_stdputpages,
130 	.vop_readlink =		VOP_EINVAL,
131 	.vop_read_pgcache =	vop_stdread_pgcache,
132 	.vop_rename =		vop_norename,
133 	.vop_revoke =		VOP_PANIC,
134 	.vop_strategy =		vop_nostrategy,
135 	.vop_unlock =		vop_stdunlock,
136 	.vop_vptocnp =		vop_stdvptocnp,
137 	.vop_vptofh =		vop_stdvptofh,
138 	.vop_unp_bind =		vop_stdunp_bind,
139 	.vop_unp_connect =	vop_stdunp_connect,
140 	.vop_unp_detach =	vop_stdunp_detach,
141 	.vop_is_text =		vop_stdis_text,
142 	.vop_set_text =		vop_stdset_text,
143 	.vop_unset_text =	vop_stdunset_text,
144 	.vop_add_writecount =	vop_stdadd_writecount,
145 	.vop_copy_file_range =	vop_stdcopy_file_range,
146 	.vop_vput_pair =	vop_stdvput_pair,
147 };
148 VFS_VOP_VECTOR_REGISTER(default_vnodeops);
149 
150 /*
151  * Series of placeholder functions for various error returns for
152  * VOPs.
153  */
154 
155 int
156 vop_eopnotsupp(struct vop_generic_args *ap)
157 {
158 	/*
159 	printf("vop_notsupp[%s]\n", ap->a_desc->vdesc_name);
160 	*/
161 
162 	return (EOPNOTSUPP);
163 }
164 
165 int
166 vop_ebadf(struct vop_generic_args *ap)
167 {
168 
169 	return (EBADF);
170 }
171 
172 int
173 vop_enotty(struct vop_generic_args *ap)
174 {
175 
176 	return (ENOTTY);
177 }
178 
179 int
180 vop_einval(struct vop_generic_args *ap)
181 {
182 
183 	return (EINVAL);
184 }
185 
186 int
187 vop_enoent(struct vop_generic_args *ap)
188 {
189 
190 	return (ENOENT);
191 }
192 
193 int
194 vop_eagain(struct vop_generic_args *ap)
195 {
196 
197 	return (EAGAIN);
198 }
199 
200 int
201 vop_null(struct vop_generic_args *ap)
202 {
203 
204 	return (0);
205 }
206 
207 /*
208  * Helper function to panic on some bad VOPs in some filesystems.
209  */
210 int
211 vop_panic(struct vop_generic_args *ap)
212 {
213 
214 	panic("filesystem goof: vop_panic[%s]", ap->a_desc->vdesc_name);
215 }
216 
217 /*
218  * vop_std<something> and vop_no<something> are default functions for use by
219  * filesystems that need the "default reasonable" implementation for a
220  * particular operation.
221  *
222  * The documentation for the operations they implement exists (if it exists)
223  * in the VOP_<SOMETHING>(9) manpage (all uppercase).
224  */
225 
226 /*
227  * Default vop for filesystems that do not support name lookup
228  */
229 static int
230 vop_nolookup(struct vop_lookup_args *ap)
231 {
232 
233 	*ap->a_vpp = NULL;
234 	return (ENOTDIR);
235 }
236 
237 /*
238  * vop_norename:
239  *
240  * Handle unlock and reference counting for arguments of vop_rename
241  * for filesystems that do not implement rename operation.
242  */
243 static int
244 vop_norename(struct vop_rename_args *ap)
245 {
246 
247 	vop_rename_fail(ap);
248 	return (EOPNOTSUPP);
249 }
250 
251 /*
252  *	vop_nostrategy:
253  *
254  *	Strategy routine for VFS devices that have none.
255  *
256  *	BIO_ERROR and B_INVAL must be cleared prior to calling any strategy
257  *	routine.  Typically this is done for a BIO_READ strategy call.
258  *	Typically B_INVAL is assumed to already be clear prior to a write
259  *	and should not be cleared manually unless you just made the buffer
260  *	invalid.  BIO_ERROR should be cleared either way.
261  */
262 
263 static int
264 vop_nostrategy (struct vop_strategy_args *ap)
265 {
266 	printf("No strategy for buffer at %p\n", ap->a_bp);
267 	vn_printf(ap->a_vp, "vnode ");
268 	ap->a_bp->b_ioflags |= BIO_ERROR;
269 	ap->a_bp->b_error = EOPNOTSUPP;
270 	bufdone(ap->a_bp);
271 	return (EOPNOTSUPP);
272 }
273 
274 /*
275  * Check if a named file exists in a given directory vnode
276  *
277  * Returns 0 if the file exists, ENOENT if it doesn't, or errors returned by
278  * vn_dir_next_dirent().
279  */
280 static int
281 dirent_exists(struct vnode *vp, const char *dirname, struct thread *td)
282 {
283 	char *dirbuf;
284 	int error, eofflag;
285 	size_t dirbuflen, len;
286 	off_t off;
287 	struct dirent *dp;
288 	struct vattr va;
289 
290 	ASSERT_VOP_LOCKED(vp, "vnode not locked");
291 	KASSERT(vp->v_type == VDIR, ("vp %p is not a directory", vp));
292 
293 	error = VOP_GETATTR(vp, &va, td->td_ucred);
294 	if (error != 0)
295 		return (error);
296 
297 	dirbuflen = MAX(DEV_BSIZE, GENERIC_MAXDIRSIZ);
298 	if (dirbuflen < va.va_blocksize)
299 		dirbuflen = va.va_blocksize;
300 	dirbuf = malloc(dirbuflen, M_TEMP, M_WAITOK);
301 
302 	len = 0;
303 	off = 0;
304 	eofflag = 0;
305 
306 	for (;;) {
307 		error = vn_dir_next_dirent(vp, td, dirbuf, dirbuflen,
308 		    &dp, &len, &off, &eofflag);
309 		if (error != 0)
310 			goto out;
311 
312 		if (len == 0)
313 			break;
314 
315 		if (dp->d_type != DT_WHT && dp->d_fileno != 0 &&
316 		    strcmp(dp->d_name, dirname) == 0)
317 			goto out;
318 	}
319 
320 	error = ENOENT;
321 
322 out:
323 	free(dirbuf, M_TEMP);
324 	return (error);
325 }
326 
327 int
328 vop_stdaccess(struct vop_access_args *ap)
329 {
330 
331 	KASSERT((ap->a_accmode & ~(VEXEC | VWRITE | VREAD | VADMIN |
332 	    VAPPEND)) == 0, ("invalid bit in accmode"));
333 
334 	return (VOP_ACCESSX(ap->a_vp, ap->a_accmode, ap->a_cred, ap->a_td));
335 }
336 
337 int
338 vop_stdaccessx(struct vop_accessx_args *ap)
339 {
340 	int error;
341 	accmode_t accmode = ap->a_accmode;
342 
343 	error = vfs_unixify_accmode(&accmode);
344 	if (error != 0)
345 		return (error);
346 
347 	if (accmode == 0)
348 		return (0);
349 
350 	return (VOP_ACCESS(ap->a_vp, accmode, ap->a_cred, ap->a_td));
351 }
352 
353 /*
354  * Advisory record locking support
355  */
356 int
357 vop_stdadvlock(struct vop_advlock_args *ap)
358 {
359 	struct vnode *vp;
360 	struct mount *mp;
361 	struct vattr vattr;
362 	int error;
363 
364 	vp = ap->a_vp;
365 
366 	/*
367 	 * Provide atomicity of open(O_CREAT | O_EXCL | O_EXLOCK) for
368 	 * local filesystems.  See vn_open_cred() for reciprocal part.
369 	 */
370 	mp = vp->v_mount;
371 	if (mp != NULL && (mp->mnt_flag & MNT_LOCAL) != 0 &&
372 	    ap->a_op == F_SETLK && (ap->a_flags & F_FIRSTOPEN) == 0) {
373 		VI_LOCK(vp);
374 		while ((vp->v_iflag & VI_FOPENING) != 0)
375 			msleep(vp, VI_MTX(vp), PLOCK, "lockfo", 0);
376 		VI_UNLOCK(vp);
377 	}
378 
379 	if (ap->a_fl->l_whence == SEEK_END) {
380 		/*
381 		 * The NFSv4 server must avoid doing a vn_lock() here, since it
382 		 * can deadlock the nfsd threads, due to a LOR.  Fortunately
383 		 * the NFSv4 server always uses SEEK_SET and this code is
384 		 * only required for the SEEK_END case.
385 		 */
386 		vn_lock(vp, LK_SHARED | LK_RETRY);
387 		error = VOP_GETATTR(vp, &vattr, curthread->td_ucred);
388 		VOP_UNLOCK(vp);
389 		if (error)
390 			return (error);
391 	} else
392 		vattr.va_size = 0;
393 
394 	return (lf_advlock(ap, &(vp->v_lockf), vattr.va_size));
395 }
396 
397 int
398 vop_stdadvlockasync(struct vop_advlockasync_args *ap)
399 {
400 	struct vnode *vp;
401 	struct vattr vattr;
402 	int error;
403 
404 	vp = ap->a_vp;
405 	if (ap->a_fl->l_whence == SEEK_END) {
406 		/* The size argument is only needed for SEEK_END. */
407 		vn_lock(vp, LK_SHARED | LK_RETRY);
408 		error = VOP_GETATTR(vp, &vattr, curthread->td_ucred);
409 		VOP_UNLOCK(vp);
410 		if (error)
411 			return (error);
412 	} else
413 		vattr.va_size = 0;
414 
415 	return (lf_advlockasync(ap, &(vp->v_lockf), vattr.va_size));
416 }
417 
418 int
419 vop_stdadvlockpurge(struct vop_advlockpurge_args *ap)
420 {
421 	struct vnode *vp;
422 
423 	vp = ap->a_vp;
424 	lf_purgelocks(vp, &vp->v_lockf);
425 	return (0);
426 }
427 
428 /*
429  * vop_stdpathconf:
430  *
431  * Standard implementation of POSIX pathconf, to get information about limits
432  * for a filesystem.
433  * Override per filesystem for the case where the filesystem has smaller
434  * limits.
435  */
436 int
437 vop_stdpathconf(struct vop_pathconf_args *ap)
438 {
439 
440 	switch (ap->a_name) {
441 		case _PC_ASYNC_IO:
442 			*ap->a_retval = _POSIX_ASYNCHRONOUS_IO;
443 			return (0);
444 		case _PC_PATH_MAX:
445 			*ap->a_retval = PATH_MAX;
446 			return (0);
447 		case _PC_ACL_EXTENDED:
448 		case _PC_ACL_NFS4:
449 		case _PC_CAP_PRESENT:
450 		case _PC_DEALLOC_PRESENT:
451 		case _PC_INF_PRESENT:
452 		case _PC_MAC_PRESENT:
453 			*ap->a_retval = 0;
454 			return (0);
455 		default:
456 			return (EINVAL);
457 	}
458 	/* NOTREACHED */
459 }
460 
461 /*
462  * Standard lock, unlock and islocked functions.
463  */
464 int
465 vop_stdlock(struct vop_lock1_args *ap)
466 {
467 	struct vnode *vp = ap->a_vp;
468 	struct mtx *ilk;
469 
470 	ilk = VI_MTX(vp);
471 	return (lockmgr_lock_flags(vp->v_vnlock, ap->a_flags,
472 	    &ilk->lock_object, ap->a_file, ap->a_line));
473 }
474 
475 /* See above. */
476 int
477 vop_stdunlock(struct vop_unlock_args *ap)
478 {
479 	struct vnode *vp = ap->a_vp;
480 
481 	return (lockmgr_unlock(vp->v_vnlock));
482 }
483 
484 /* See above. */
485 int
486 vop_stdislocked(struct vop_islocked_args *ap)
487 {
488 
489 	return (lockstatus(ap->a_vp->v_vnlock));
490 }
491 
492 /*
493  * Variants of the above set.
494  *
495  * Differences are:
496  * - shared locking disablement is not supported
497  * - v_vnlock pointer is not honored
498  */
499 int
500 vop_lock(struct vop_lock1_args *ap)
501 {
502 	struct vnode *vp = ap->a_vp;
503 	int flags = ap->a_flags;
504 	struct mtx *ilk;
505 
506 	MPASS(vp->v_vnlock == &vp->v_lock);
507 
508 	if (__predict_false((flags & ~(LK_TYPE_MASK | LK_NODDLKTREAT | LK_RETRY)) != 0))
509 		goto other;
510 
511 	switch (flags & LK_TYPE_MASK) {
512 	case LK_SHARED:
513 		return (lockmgr_slock(&vp->v_lock, flags, ap->a_file, ap->a_line));
514 	case LK_EXCLUSIVE:
515 		return (lockmgr_xlock(&vp->v_lock, flags, ap->a_file, ap->a_line));
516 	}
517 other:
518 	ilk = VI_MTX(vp);
519 	return (lockmgr_lock_flags(&vp->v_lock, flags,
520 	    &ilk->lock_object, ap->a_file, ap->a_line));
521 }
522 
523 int
524 vop_unlock(struct vop_unlock_args *ap)
525 {
526 	struct vnode *vp = ap->a_vp;
527 
528 	MPASS(vp->v_vnlock == &vp->v_lock);
529 
530 	return (lockmgr_unlock(&vp->v_lock));
531 }
532 
533 int
534 vop_islocked(struct vop_islocked_args *ap)
535 {
536 	struct vnode *vp = ap->a_vp;
537 
538 	MPASS(vp->v_vnlock == &vp->v_lock);
539 
540 	return (lockstatus(&vp->v_lock));
541 }
542 
543 /*
544  * Return true for select/poll.
545  */
546 int
547 vop_nopoll(struct vop_poll_args *ap)
548 {
549 
550 	if (ap->a_events & ~POLLSTANDARD)
551 		return (POLLNVAL);
552 	return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
553 }
554 
555 /*
556  * Implement poll for local filesystems that support it.
557  */
558 int
559 vop_stdpoll(struct vop_poll_args *ap)
560 {
561 	if (ap->a_events & ~POLLSTANDARD)
562 		return (vn_pollrecord(ap->a_vp, ap->a_td, ap->a_events));
563 	return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
564 }
565 
566 /*
567  * Return our mount point, as we will take charge of the writes.
568  */
569 int
570 vop_stdgetwritemount(struct vop_getwritemount_args *ap)
571 {
572 	struct mount *mp;
573 	struct vnode *vp;
574 
575 	/*
576 	 * Note that having a reference does not prevent forced unmount from
577 	 * setting ->v_mount to NULL after the lock gets released. This is of
578 	 * no consequence for typical consumers (most notably vn_start_write)
579 	 * since in this case the vnode is VIRF_DOOMED. Unmount might have
580 	 * progressed far enough that its completion is only delayed by the
581 	 * reference obtained here. The consumer only needs to concern itself
582 	 * with releasing it.
583 	 */
584 	vp = ap->a_vp;
585 	mp = vfs_ref_from_vp(vp);
586 	*(ap->a_mpp) = mp;
587 	return (0);
588 }
589 
590 /*
591  * If the file system doesn't implement VOP_BMAP, then return sensible defaults:
592  * - Return the vnode's bufobj instead of any underlying device's bufobj
593  * - Calculate the physical block number as if there were equal size
594  *   consecutive blocks, but
595  * - Report no contiguous runs of blocks.
596  */
597 int
598 vop_stdbmap(struct vop_bmap_args *ap)
599 {
600 
601 	if (ap->a_bop != NULL)
602 		*ap->a_bop = &ap->a_vp->v_bufobj;
603 	if (ap->a_bnp != NULL)
604 		*ap->a_bnp = ap->a_bn * btodb(ap->a_vp->v_mount->mnt_stat.f_iosize);
605 	if (ap->a_runp != NULL)
606 		*ap->a_runp = 0;
607 	if (ap->a_runb != NULL)
608 		*ap->a_runb = 0;
609 	return (0);
610 }
611 
612 int
613 vop_stdfsync(struct vop_fsync_args *ap)
614 {
615 
616 	return (vn_fsync_buf(ap->a_vp, ap->a_waitfor));
617 }
618 
619 static int
620 vop_stdfdatasync(struct vop_fdatasync_args *ap)
621 {
622 
623 	return (VOP_FSYNC(ap->a_vp, MNT_WAIT, ap->a_td));
624 }
625 
626 int
627 vop_stdfdatasync_buf(struct vop_fdatasync_args *ap)
628 {
629 
630 	return (vn_fsync_buf(ap->a_vp, MNT_WAIT));
631 }
632 
633 /* XXX Needs good comment and more info in the manpage (VOP_GETPAGES(9)). */
634 int
635 vop_stdgetpages(struct vop_getpages_args *ap)
636 {
637 
638 	return vnode_pager_generic_getpages(ap->a_vp, ap->a_m,
639 	    ap->a_count, ap->a_rbehind, ap->a_rahead, NULL, NULL);
640 }
641 
642 static int
643 vop_stdgetpages_async(struct vop_getpages_async_args *ap)
644 {
645 	int error;
646 
647 	error = VOP_GETPAGES(ap->a_vp, ap->a_m, ap->a_count, ap->a_rbehind,
648 	    ap->a_rahead);
649 	if (ap->a_iodone != NULL)
650 		ap->a_iodone(ap->a_arg, ap->a_m, ap->a_count, error);
651 	return (error);
652 }
653 
654 int
655 vop_stdkqfilter(struct vop_kqfilter_args *ap)
656 {
657 	return vfs_kqfilter(ap);
658 }
659 
660 /* XXX Needs good comment and more info in the manpage (VOP_PUTPAGES(9)). */
661 int
662 vop_stdputpages(struct vop_putpages_args *ap)
663 {
664 
665 	return vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count,
666 	     ap->a_sync, ap->a_rtvals);
667 }
668 
669 int
670 vop_stdvptofh(struct vop_vptofh_args *ap)
671 {
672 	return (EOPNOTSUPP);
673 }
674 
675 int
676 vop_stdvptocnp(struct vop_vptocnp_args *ap)
677 {
678 	struct vnode *const vp = ap->a_vp;
679 	struct vnode **const dvp = ap->a_vpp;
680 	char *buf = ap->a_buf;
681 	size_t *buflen = ap->a_buflen;
682 	char *dirbuf;
683 	int i = *buflen;
684 	int error = 0, covered = 0;
685 	int eofflag, flags, locked;
686 	size_t dirbuflen, len;
687 	off_t off;
688 	ino_t fileno;
689 	struct vattr va;
690 	struct nameidata nd;
691 	struct thread *const td = curthread;
692 	struct ucred *const cred = td->td_ucred;
693 	struct dirent *dp;
694 	struct vnode *mvp;
695 
696 	if (vp->v_type != VDIR)
697 		return (ENOENT);
698 
699 	error = VOP_GETATTR(vp, &va, cred);
700 	if (error)
701 		return (error);
702 
703 	VREF(vp);
704 	locked = VOP_ISLOCKED(vp);
705 	VOP_UNLOCK(vp);
706 	NDINIT_ATVP(&nd, LOOKUP, FOLLOW | LOCKSHARED | LOCKLEAF, UIO_SYSSPACE,
707 	    "..", vp);
708 	flags = FREAD;
709 	error = vn_open_cred(&nd, &flags, 0, VN_OPEN_NOAUDIT, cred, NULL);
710 	if (error) {
711 		vn_lock(vp, locked | LK_RETRY);
712 		return (error);
713 	}
714 	NDFREE_PNBUF(&nd);
715 
716 	mvp = *dvp = nd.ni_vp;
717 
718 	if (vp->v_mount != (*dvp)->v_mount &&
719 	    ((*dvp)->v_vflag & VV_ROOT) &&
720 	    ((*dvp)->v_mount->mnt_flag & MNT_UNION)) {
721 		*dvp = (*dvp)->v_mount->mnt_vnodecovered;
722 		VREF(mvp);
723 		VOP_UNLOCK(mvp);
724 		vn_close(mvp, FREAD, cred, td);
725 		VREF(*dvp);
726 		vn_lock(*dvp, LK_SHARED | LK_RETRY);
727 		covered = 1;
728 	}
729 
730 	fileno = va.va_fileid;
731 
732 	dirbuflen = MAX(DEV_BSIZE, GENERIC_MAXDIRSIZ);
733 	if (dirbuflen < va.va_blocksize)
734 		dirbuflen = va.va_blocksize;
735 	dirbuf = malloc(dirbuflen, M_TEMP, M_WAITOK);
736 
737 	if ((*dvp)->v_type != VDIR) {
738 		error = ENOENT;
739 		goto out;
740 	}
741 
742 	len = 0;
743 	off = 0;
744 	eofflag = 0;
745 
746 	for (;;) {
747 		/* call VOP_READDIR of parent */
748 		error = vn_dir_next_dirent(*dvp, td,
749 		    dirbuf, dirbuflen, &dp, &len, &off, &eofflag);
750 		if (error != 0)
751 			goto out;
752 
753 		if (len == 0) {
754 			error = ENOENT;
755 			goto out;
756 		}
757 
758 		if ((dp->d_type != DT_WHT) &&
759 		    (dp->d_fileno == fileno)) {
760 			if (covered) {
761 				VOP_UNLOCK(*dvp);
762 				vn_lock(mvp, LK_SHARED | LK_RETRY);
763 				if (dirent_exists(mvp, dp->d_name, td) == 0) {
764 					error = ENOENT;
765 					VOP_UNLOCK(mvp);
766 					vn_lock(*dvp, LK_SHARED | LK_RETRY);
767 					goto out;
768 				}
769 				VOP_UNLOCK(mvp);
770 				vn_lock(*dvp, LK_SHARED | LK_RETRY);
771 			}
772 			i -= dp->d_namlen;
773 
774 			if (i < 0) {
775 				error = ENOMEM;
776 				goto out;
777 			}
778 			if (dp->d_namlen == 1 && dp->d_name[0] == '.') {
779 				error = ENOENT;
780 			} else {
781 				bcopy(dp->d_name, buf + i, dp->d_namlen);
782 				error = 0;
783 			}
784 			goto out;
785 		}
786 	}
787 
788 out:
789 	free(dirbuf, M_TEMP);
790 	if (!error) {
791 		*buflen = i;
792 		vref(*dvp);
793 	}
794 	if (covered) {
795 		vput(*dvp);
796 		vrele(mvp);
797 	} else {
798 		VOP_UNLOCK(mvp);
799 		vn_close(mvp, FREAD, cred, td);
800 	}
801 	vn_lock(vp, locked | LK_RETRY);
802 	return (error);
803 }
804 
805 int
806 vop_stdallocate(struct vop_allocate_args *ap)
807 {
808 #ifdef __notyet__
809 	struct statfs *sfs;
810 	off_t maxfilesize = 0;
811 #endif
812 	struct iovec aiov;
813 	struct vattr vattr, *vap;
814 	struct uio auio;
815 	off_t fsize, len, cur, offset;
816 	uint8_t *buf;
817 	struct thread *td;
818 	struct vnode *vp;
819 	size_t iosize;
820 	int error;
821 
822 	buf = NULL;
823 	error = 0;
824 	td = curthread;
825 	vap = &vattr;
826 	vp = ap->a_vp;
827 	len = *ap->a_len;
828 	offset = *ap->a_offset;
829 
830 	error = VOP_GETATTR(vp, vap, ap->a_cred);
831 	if (error != 0)
832 		goto out;
833 	fsize = vap->va_size;
834 	iosize = vap->va_blocksize;
835 	if (iosize == 0)
836 		iosize = BLKDEV_IOSIZE;
837 	if (iosize > maxphys)
838 		iosize = maxphys;
839 	buf = malloc(iosize, M_TEMP, M_WAITOK);
840 
841 #ifdef __notyet__
842 	/*
843 	 * Check if the filesystem sets f_maxfilesize; if not use
844 	 * VOP_SETATTR to perform the check.
845 	 */
846 	sfs = malloc(sizeof(struct statfs), M_STATFS, M_WAITOK);
847 	error = VFS_STATFS(vp->v_mount, sfs, td);
848 	if (error == 0)
849 		maxfilesize = sfs->f_maxfilesize;
850 	free(sfs, M_STATFS);
851 	if (error != 0)
852 		goto out;
853 	if (maxfilesize) {
854 		if (offset > maxfilesize || len > maxfilesize ||
855 		    offset + len > maxfilesize) {
856 			error = EFBIG;
857 			goto out;
858 		}
859 	} else
860 #endif
861 	if (offset + len > vap->va_size) {
862 		/*
863 		 * Test offset + len against the filesystem's maxfilesize.
864 		 */
865 		VATTR_NULL(vap);
866 		vap->va_size = offset + len;
867 		error = VOP_SETATTR(vp, vap, ap->a_cred);
868 		if (error != 0)
869 			goto out;
870 		VATTR_NULL(vap);
871 		vap->va_size = fsize;
872 		error = VOP_SETATTR(vp, vap, ap->a_cred);
873 		if (error != 0)
874 			goto out;
875 	}
876 
877 	for (;;) {
878 		/*
879 		 * Read and write back anything below the nominal file
880 		 * size.  There's currently no way outside the filesystem
881 		 * to know whether this area is sparse or not.
882 		 */
883 		cur = iosize;
884 		if ((offset % iosize) != 0)
885 			cur -= (offset % iosize);
886 		if (cur > len)
887 			cur = len;
888 		if (offset < fsize) {
889 			aiov.iov_base = buf;
890 			aiov.iov_len = cur;
891 			auio.uio_iov = &aiov;
892 			auio.uio_iovcnt = 1;
893 			auio.uio_offset = offset;
894 			auio.uio_resid = cur;
895 			auio.uio_segflg = UIO_SYSSPACE;
896 			auio.uio_rw = UIO_READ;
897 			auio.uio_td = td;
898 			error = VOP_READ(vp, &auio, ap->a_ioflag, ap->a_cred);
899 			if (error != 0)
900 				break;
901 			if (auio.uio_resid > 0) {
902 				bzero(buf + cur - auio.uio_resid,
903 				    auio.uio_resid);
904 			}
905 		} else {
906 			bzero(buf, cur);
907 		}
908 
909 		aiov.iov_base = buf;
910 		aiov.iov_len = cur;
911 		auio.uio_iov = &aiov;
912 		auio.uio_iovcnt = 1;
913 		auio.uio_offset = offset;
914 		auio.uio_resid = cur;
915 		auio.uio_segflg = UIO_SYSSPACE;
916 		auio.uio_rw = UIO_WRITE;
917 		auio.uio_td = td;
918 
919 		error = VOP_WRITE(vp, &auio, ap->a_ioflag, ap->a_cred);
920 		if (error != 0)
921 			break;
922 
923 		len -= cur;
924 		offset += cur;
925 		if (len == 0)
926 			break;
927 		if (should_yield())
928 			break;
929 	}
930 
931  out:
932 	*ap->a_len = len;
933 	*ap->a_offset = offset;
934 	free(buf, M_TEMP);
935 	return (error);
936 }
937 
938 static int
939 vp_zerofill(struct vnode *vp, struct vattr *vap, off_t *offsetp, off_t *lenp,
940     int ioflag, struct ucred *cred)
941 {
942 	int iosize;
943 	int error = 0;
944 	struct iovec aiov;
945 	struct uio auio;
946 	struct thread *td;
947 	off_t offset, len;
948 
949 	iosize = vap->va_blocksize;
950 	td = curthread;
951 	offset = *offsetp;
952 	len = *lenp;
953 
954 	if (iosize == 0)
955 		iosize = BLKDEV_IOSIZE;
956 	/* If va_blocksize is 512 bytes, iosize will be 4 kilobytes */
957 	iosize = min(iosize * 8, ZERO_REGION_SIZE);
958 
959 	while (len > 0) {
960 		int xfersize = iosize;
961 		if (offset % iosize != 0)
962 			xfersize -= offset % iosize;
963 		if (xfersize > len)
964 			xfersize = len;
965 
966 		aiov.iov_base = __DECONST(void *, zero_region);
967 		aiov.iov_len = xfersize;
968 		auio.uio_iov = &aiov;
969 		auio.uio_iovcnt = 1;
970 		auio.uio_offset = offset;
971 		auio.uio_resid = xfersize;
972 		auio.uio_segflg = UIO_SYSSPACE;
973 		auio.uio_rw = UIO_WRITE;
974 		auio.uio_td = td;
975 
976 		error = VOP_WRITE(vp, &auio, ioflag, cred);
977 		if (error != 0) {
978 			len -= xfersize - auio.uio_resid;
979 			offset += xfersize - auio.uio_resid;
980 			break;
981 		}
982 
983 		len -= xfersize;
984 		offset += xfersize;
985 	}
986 
987 	*offsetp = offset;
988 	*lenp = len;
989 	return (error);
990 }
991 
992 int
993 vop_stddeallocate(struct vop_deallocate_args *ap)
994 {
995 	struct vnode *vp;
996 	off_t offset, len;
997 	struct ucred *cred;
998 	int error;
999 	struct vattr va;
1000 	off_t noff, xfersize, rem;
1001 
1002 	vp = ap->a_vp;
1003 	offset = *ap->a_offset;
1004 	cred = ap->a_cred;
1005 
1006 	error = VOP_GETATTR(vp, &va, cred);
1007 	if (error)
1008 		return (error);
1009 
1010 	len = omin((off_t)va.va_size - offset, *ap->a_len);
1011 	while (len > 0) {
1012 		noff = offset;
1013 		error = vn_bmap_seekhole_locked(vp, FIOSEEKDATA, &noff, cred);
1014 		if (error) {
1015 			if (error != ENXIO)
1016 				/* XXX: Is it okay to fallback further? */
1017 				goto out;
1018 
1019 			/*
1020 			 * No more data region to be filled
1021 			 */
1022 			offset += len;
1023 			len = 0;
1024 			error = 0;
1025 			break;
1026 		}
1027 		KASSERT(noff >= offset, ("FIOSEEKDATA going backward"));
1028 		if (noff != offset) {
1029 			xfersize = omin(noff - offset, len);
1030 			len -= xfersize;
1031 			offset += xfersize;
1032 			if (len == 0)
1033 				break;
1034 		}
1035 		error = vn_bmap_seekhole_locked(vp, FIOSEEKHOLE, &noff, cred);
1036 		if (error)
1037 			goto out;
1038 
1039 		/* Fill zeroes */
1040 		xfersize = rem = omin(noff - offset, len);
1041 		error = vp_zerofill(vp, &va, &offset, &rem, ap->a_ioflag, cred);
1042 		if (error) {
1043 			len -= xfersize - rem;
1044 			goto out;
1045 		}
1046 
1047 		len -= xfersize;
1048 		if (should_yield())
1049 			break;
1050 	}
1051 	/* Handle the case when offset is beyond EOF */
1052 	if (len < 0)
1053 		len = 0;
1054 out:
1055 	*ap->a_offset = offset;
1056 	*ap->a_len = len;
1057 	return (error);
1058 }
1059 
1060 int
1061 vop_stdadvise(struct vop_advise_args *ap)
1062 {
1063 	struct vnode *vp;
1064 	struct bufobj *bo;
1065 	daddr_t startn, endn;
1066 	off_t bstart, bend, start, end;
1067 	int bsize, error;
1068 
1069 	vp = ap->a_vp;
1070 	switch (ap->a_advice) {
1071 	case POSIX_FADV_WILLNEED:
1072 		/*
1073 		 * Do nothing for now.  Filesystems should provide a
1074 		 * custom method which starts an asynchronous read of
1075 		 * the requested region.
1076 		 */
1077 		error = 0;
1078 		break;
1079 	case POSIX_FADV_DONTNEED:
1080 		error = 0;
1081 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1082 		if (VN_IS_DOOMED(vp)) {
1083 			VOP_UNLOCK(vp);
1084 			break;
1085 		}
1086 
1087 		/*
1088 		 * Round to block boundaries (and later possibly further to
1089 		 * page boundaries).  Applications cannot reasonably be aware
1090 		 * of the boundaries, and the rounding must be to expand at
1091 		 * both extremities to cover enough.  It still doesn't cover
1092 		 * read-ahead.  For partial blocks, this gives unnecessary
1093 		 * discarding of buffers but is efficient enough since the
1094 		 * pages usually remain in VMIO for some time.
1095 		 */
1096 		bsize = vp->v_bufobj.bo_bsize;
1097 		bstart = rounddown(ap->a_start, bsize);
1098 		bend = roundup(ap->a_end, bsize);
1099 
1100 		/*
1101 		 * Deactivate pages in the specified range from the backing VM
1102 		 * object.  Pages that are resident in the buffer cache will
1103 		 * remain wired until their corresponding buffers are released
1104 		 * below.
1105 		 */
1106 		if (vp->v_object != NULL) {
1107 			start = trunc_page(bstart);
1108 			end = round_page(bend);
1109 			VM_OBJECT_RLOCK(vp->v_object);
1110 			vm_object_page_noreuse(vp->v_object, OFF_TO_IDX(start),
1111 			    OFF_TO_IDX(end));
1112 			VM_OBJECT_RUNLOCK(vp->v_object);
1113 		}
1114 
1115 		bo = &vp->v_bufobj;
1116 		BO_RLOCK(bo);
1117 		startn = bstart / bsize;
1118 		endn = bend / bsize;
1119 		error = bnoreuselist(&bo->bo_clean, bo, startn, endn);
1120 		if (error == 0)
1121 			error = bnoreuselist(&bo->bo_dirty, bo, startn, endn);
1122 		BO_RUNLOCK(bo);
1123 		VOP_UNLOCK(vp);
1124 		break;
1125 	default:
1126 		error = EINVAL;
1127 		break;
1128 	}
1129 	return (error);
1130 }
1131 
1132 int
1133 vop_stdunp_bind(struct vop_unp_bind_args *ap)
1134 {
1135 
1136 	ap->a_vp->v_unpcb = ap->a_unpcb;
1137 	return (0);
1138 }
1139 
1140 int
1141 vop_stdunp_connect(struct vop_unp_connect_args *ap)
1142 {
1143 
1144 	*ap->a_unpcb = ap->a_vp->v_unpcb;
1145 	return (0);
1146 }
1147 
1148 int
1149 vop_stdunp_detach(struct vop_unp_detach_args *ap)
1150 {
1151 
1152 	ap->a_vp->v_unpcb = NULL;
1153 	return (0);
1154 }
1155 
1156 static int
1157 vop_stdis_text(struct vop_is_text_args *ap)
1158 {
1159 
1160 	return (atomic_load_int(&ap->a_vp->v_writecount) < 0);
1161 }
1162 
1163 int
1164 vop_stdset_text(struct vop_set_text_args *ap)
1165 {
1166 	struct vnode *vp;
1167 	int n;
1168 	bool gotref;
1169 
1170 	vp = ap->a_vp;
1171 
1172 	n = atomic_load_int(&vp->v_writecount);
1173 	for (;;) {
1174 		if (__predict_false(n > 0)) {
1175 			return (ETXTBSY);
1176 		}
1177 
1178 		/*
1179 		 * Transition point, we may need to grab a reference on the vnode.
1180 		 *
1181 		 * Take the ref early As a safety measure against bogus calls
1182 		 * to vop_stdunset_text.
1183 		 */
1184 		if (n == 0) {
1185 			gotref = false;
1186 			if ((vn_irflag_read(vp) & VIRF_TEXT_REF) != 0) {
1187 				vref(vp);
1188 				gotref = true;
1189 			}
1190 			if (atomic_fcmpset_int(&vp->v_writecount, &n, -1)) {
1191 				return (0);
1192 			}
1193 			if (gotref) {
1194 				vunref(vp);
1195 			}
1196 			continue;
1197 		}
1198 
1199 		MPASS(n < 0);
1200 		if (atomic_fcmpset_int(&vp->v_writecount, &n, n - 1)) {
1201 			return (0);
1202 		}
1203 	}
1204 	__assert_unreachable();
1205 }
1206 
1207 static int
1208 vop_stdunset_text(struct vop_unset_text_args *ap)
1209 {
1210 	struct vnode *vp;
1211 	int n;
1212 
1213 	vp = ap->a_vp;
1214 
1215 	n = atomic_load_int(&vp->v_writecount);
1216 	for (;;) {
1217 		if (__predict_false(n >= 0)) {
1218 			return (EINVAL);
1219 		}
1220 
1221 		/*
1222 		 * Transition point, we may need to release a reference on the vnode.
1223 		 */
1224 		if (n == -1) {
1225 			if (atomic_fcmpset_int(&vp->v_writecount, &n, 0)) {
1226 				if ((vn_irflag_read(vp) & VIRF_TEXT_REF) != 0) {
1227 					vunref(vp);
1228 				}
1229 				return (0);
1230 			}
1231 			continue;
1232 		}
1233 
1234 		MPASS(n < -1);
1235 		if (atomic_fcmpset_int(&vp->v_writecount, &n, n + 1)) {
1236 			return (0);
1237 		}
1238 	}
1239 	__assert_unreachable();
1240 }
1241 
1242 static int __always_inline
1243 vop_stdadd_writecount_impl(struct vop_add_writecount_args *ap, bool handle_msync)
1244 {
1245 	struct vnode *vp;
1246 	struct mount *mp __diagused;
1247 	int n;
1248 
1249 	vp = ap->a_vp;
1250 
1251 #ifdef INVARIANTS
1252 	mp = vp->v_mount;
1253 	if (mp != NULL) {
1254 		if (handle_msync) {
1255 			VNPASS((mp->mnt_kern_flag & MNTK_NOMSYNC) == 0, vp);
1256 		} else {
1257 			VNPASS((mp->mnt_kern_flag & MNTK_NOMSYNC) != 0, vp);
1258 		}
1259 	}
1260 #endif
1261 
1262 	n = atomic_load_int(&vp->v_writecount);
1263 	for (;;) {
1264 		if (__predict_false(n < 0)) {
1265 			return (ETXTBSY);
1266 		}
1267 
1268 		VNASSERT(n + ap->a_inc >= 0, vp,
1269 		    ("neg writecount increment %d + %d = %d", n, ap->a_inc,
1270 		    n + ap->a_inc));
1271 		if (n == 0) {
1272 			if (handle_msync) {
1273 				vlazy(vp);
1274 			}
1275 		}
1276 
1277 		if (atomic_fcmpset_int(&vp->v_writecount, &n, n + ap->a_inc)) {
1278 			return (0);
1279 		}
1280 	}
1281 	__assert_unreachable();
1282 }
1283 
1284 int
1285 vop_stdadd_writecount(struct vop_add_writecount_args *ap)
1286 {
1287 
1288 	return (vop_stdadd_writecount_impl(ap, true));
1289 }
1290 
1291 int
1292 vop_stdadd_writecount_nomsync(struct vop_add_writecount_args *ap)
1293 {
1294 
1295 	return (vop_stdadd_writecount_impl(ap, false));
1296 }
1297 
1298 int
1299 vop_stdneed_inactive(struct vop_need_inactive_args *ap)
1300 {
1301 
1302 	return (1);
1303 }
1304 
1305 int
1306 vop_stdioctl(struct vop_ioctl_args *ap)
1307 {
1308 	struct vnode *vp;
1309 	struct vattr va;
1310 	off_t *offp;
1311 	int error;
1312 
1313 	switch (ap->a_command) {
1314 	case FIOSEEKDATA:
1315 	case FIOSEEKHOLE:
1316 		vp = ap->a_vp;
1317 		error = vn_lock(vp, LK_SHARED);
1318 		if (error != 0)
1319 			return (EBADF);
1320 		if (vp->v_type == VREG)
1321 			error = VOP_GETATTR(vp, &va, ap->a_cred);
1322 		else
1323 			error = ENOTTY;
1324 		if (error == 0) {
1325 			offp = ap->a_data;
1326 			if (*offp < 0 || *offp >= va.va_size)
1327 				error = ENXIO;
1328 			else if (ap->a_command == FIOSEEKHOLE)
1329 				*offp = va.va_size;
1330 		}
1331 		VOP_UNLOCK(vp);
1332 		break;
1333 	default:
1334 		error = ENOTTY;
1335 		break;
1336 	}
1337 	return (error);
1338 }
1339 
1340 /*
1341  * vfs default ops
1342  * used to fill the vfs function table to get reasonable default return values.
1343  */
1344 int
1345 vfs_stdroot(struct mount *mp, int flags, struct vnode **vpp)
1346 {
1347 
1348 	return (EOPNOTSUPP);
1349 }
1350 
1351 int
1352 vfs_stdstatfs(struct mount *mp, struct statfs *sbp)
1353 {
1354 
1355 	return (EOPNOTSUPP);
1356 }
1357 
1358 int
1359 vfs_stdquotactl(struct mount *mp, int cmds, uid_t uid, void *arg, bool *mp_busy)
1360 {
1361 	return (EOPNOTSUPP);
1362 }
1363 
1364 int
1365 vfs_stdsync(struct mount *mp, int waitfor)
1366 {
1367 	struct vnode *vp, *mvp;
1368 	struct thread *td;
1369 	int error, lockreq, allerror = 0;
1370 
1371 	td = curthread;
1372 	lockreq = LK_EXCLUSIVE | LK_INTERLOCK;
1373 	if (waitfor != MNT_WAIT)
1374 		lockreq |= LK_NOWAIT;
1375 	/*
1376 	 * Force stale buffer cache information to be flushed.
1377 	 */
1378 loop:
1379 	MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
1380 		if (vp->v_bufobj.bo_dirty.bv_cnt == 0) {
1381 			VI_UNLOCK(vp);
1382 			continue;
1383 		}
1384 		if ((error = vget(vp, lockreq)) != 0) {
1385 			if (error == ENOENT) {
1386 				MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
1387 				goto loop;
1388 			}
1389 			continue;
1390 		}
1391 		error = VOP_FSYNC(vp, waitfor, td);
1392 		if (error)
1393 			allerror = error;
1394 		vput(vp);
1395 	}
1396 	return (allerror);
1397 }
1398 
1399 int
1400 vfs_stdnosync(struct mount *mp, int waitfor)
1401 {
1402 
1403 	return (0);
1404 }
1405 
1406 static int
1407 vop_stdcopy_file_range(struct vop_copy_file_range_args *ap)
1408 {
1409 	int error;
1410 
1411 	error = vn_generic_copy_file_range(ap->a_invp, ap->a_inoffp,
1412 	    ap->a_outvp, ap->a_outoffp, ap->a_lenp, ap->a_flags, ap->a_incred,
1413 	    ap->a_outcred, ap->a_fsizetd);
1414 	return (error);
1415 }
1416 
1417 int
1418 vfs_stdvget(struct mount *mp, ino_t ino, int flags, struct vnode **vpp)
1419 {
1420 
1421 	return (EOPNOTSUPP);
1422 }
1423 
1424 int
1425 vfs_stdfhtovp(struct mount *mp, struct fid *fhp, int flags, struct vnode **vpp)
1426 {
1427 
1428 	return (EOPNOTSUPP);
1429 }
1430 
1431 int
1432 vfs_stdinit(struct vfsconf *vfsp)
1433 {
1434 
1435 	return (0);
1436 }
1437 
1438 int
1439 vfs_stduninit(struct vfsconf *vfsp)
1440 {
1441 
1442 	return(0);
1443 }
1444 
1445 int
1446 vfs_stdextattrctl(struct mount *mp, int cmd, struct vnode *filename_vp,
1447     int attrnamespace, const char *attrname)
1448 {
1449 
1450 	if (filename_vp != NULL)
1451 		VOP_UNLOCK(filename_vp);
1452 	return (EOPNOTSUPP);
1453 }
1454 
1455 int
1456 vfs_stdsysctl(struct mount *mp, fsctlop_t op, struct sysctl_req *req)
1457 {
1458 
1459 	return (EOPNOTSUPP);
1460 }
1461 
1462 static vop_bypass_t *
1463 bp_by_off(struct vop_vector *vop, struct vop_generic_args *a)
1464 {
1465 
1466 	return (*(vop_bypass_t **)((char *)vop + a->a_desc->vdesc_vop_offset));
1467 }
1468 
1469 int
1470 vop_sigdefer(struct vop_vector *vop, struct vop_generic_args *a)
1471 {
1472 	vop_bypass_t *bp;
1473 	int prev_stops, rc;
1474 
1475 	bp = bp_by_off(vop, a);
1476 	MPASS(bp != NULL);
1477 
1478 	prev_stops = sigdeferstop(SIGDEFERSTOP_SILENT);
1479 	rc = bp(a);
1480 	sigallowstop(prev_stops);
1481 	return (rc);
1482 }
1483 
1484 static int
1485 vop_stdstat(struct vop_stat_args *a)
1486 {
1487 	struct vattr vattr;
1488 	struct vattr *vap;
1489 	struct vnode *vp;
1490 	struct stat *sb;
1491 	int error;
1492 	u_short mode;
1493 
1494 	vp = a->a_vp;
1495 	sb = a->a_sb;
1496 
1497 	error = vop_stat_helper_pre(a);
1498 	if (error != 0)
1499 		return (error);
1500 
1501 	vap = &vattr;
1502 
1503 	/*
1504 	 * Initialize defaults for new and unusual fields, so that file
1505 	 * systems which don't support these fields don't need to know
1506 	 * about them.
1507 	 */
1508 	vap->va_birthtime.tv_sec = -1;
1509 	vap->va_birthtime.tv_nsec = 0;
1510 	vap->va_fsid = VNOVAL;
1511 	vap->va_gen = 0;
1512 	vap->va_rdev = NODEV;
1513 
1514 	error = VOP_GETATTR(vp, vap, a->a_active_cred);
1515 	if (error)
1516 		goto out;
1517 
1518 	/*
1519 	 * Zero the spare stat fields
1520 	 */
1521 	bzero(sb, sizeof *sb);
1522 
1523 	/*
1524 	 * Copy from vattr table
1525 	 */
1526 	if (vap->va_fsid != VNOVAL)
1527 		sb->st_dev = vap->va_fsid;
1528 	else
1529 		sb->st_dev = vp->v_mount->mnt_stat.f_fsid.val[0];
1530 	sb->st_ino = vap->va_fileid;
1531 	mode = vap->va_mode;
1532 	switch (vap->va_type) {
1533 	case VREG:
1534 		mode |= S_IFREG;
1535 		break;
1536 	case VDIR:
1537 		mode |= S_IFDIR;
1538 		break;
1539 	case VBLK:
1540 		mode |= S_IFBLK;
1541 		break;
1542 	case VCHR:
1543 		mode |= S_IFCHR;
1544 		break;
1545 	case VLNK:
1546 		mode |= S_IFLNK;
1547 		break;
1548 	case VSOCK:
1549 		mode |= S_IFSOCK;
1550 		break;
1551 	case VFIFO:
1552 		mode |= S_IFIFO;
1553 		break;
1554 	default:
1555 		error = EBADF;
1556 		goto out;
1557 	}
1558 	sb->st_mode = mode;
1559 	sb->st_nlink = vap->va_nlink;
1560 	sb->st_uid = vap->va_uid;
1561 	sb->st_gid = vap->va_gid;
1562 	sb->st_rdev = vap->va_rdev;
1563 	if (vap->va_size > OFF_MAX) {
1564 		error = EOVERFLOW;
1565 		goto out;
1566 	}
1567 	sb->st_size = vap->va_size;
1568 	sb->st_atim.tv_sec = vap->va_atime.tv_sec;
1569 	sb->st_atim.tv_nsec = vap->va_atime.tv_nsec;
1570 	sb->st_mtim.tv_sec = vap->va_mtime.tv_sec;
1571 	sb->st_mtim.tv_nsec = vap->va_mtime.tv_nsec;
1572 	sb->st_ctim.tv_sec = vap->va_ctime.tv_sec;
1573 	sb->st_ctim.tv_nsec = vap->va_ctime.tv_nsec;
1574 	sb->st_birthtim.tv_sec = vap->va_birthtime.tv_sec;
1575 	sb->st_birthtim.tv_nsec = vap->va_birthtime.tv_nsec;
1576 
1577 	/*
1578 	 * According to www.opengroup.org, the meaning of st_blksize is
1579 	 *   "a filesystem-specific preferred I/O block size for this
1580 	 *    object.  In some filesystem types, this may vary from file
1581 	 *    to file"
1582 	 * Use minimum/default of PAGE_SIZE (e.g. for VCHR).
1583 	 */
1584 
1585 	sb->st_blksize = max(PAGE_SIZE, vap->va_blocksize);
1586 	sb->st_flags = vap->va_flags;
1587 	sb->st_blocks = vap->va_bytes / S_BLKSIZE;
1588 	sb->st_gen = vap->va_gen;
1589 out:
1590 	return (vop_stat_helper_post(a, error));
1591 }
1592 
1593 static int
1594 vop_stdread_pgcache(struct vop_read_pgcache_args *ap __unused)
1595 {
1596 	return (EJUSTRETURN);
1597 }
1598 
1599 static int
1600 vop_stdvput_pair(struct vop_vput_pair_args *ap)
1601 {
1602 	struct vnode *dvp, *vp, **vpp;
1603 
1604 	dvp = ap->a_dvp;
1605 	vpp = ap->a_vpp;
1606 	vput(dvp);
1607 	if (vpp != NULL && ap->a_unlock_vp && (vp = *vpp) != NULL)
1608 		vput(vp);
1609 	return (0);
1610 }
1611