xref: /freebsd/sys/kern/vfs_default.c (revision d2387d42b8da231a5b95cbc313825fb2aadf26f6)
1 /*
2  * Copyright (c) 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed
6  * to Berkeley by John Heidemann of the UCLA Ficus project.
7  *
8  * Source: * @(#)i405_init.c 2.10 92/04/27 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. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  */
38 
39 #include <sys/cdefs.h>
40 __FBSDID("$FreeBSD$");
41 
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/bio.h>
45 #include <sys/buf.h>
46 #include <sys/conf.h>
47 #include <sys/kernel.h>
48 #include <sys/limits.h>
49 #include <sys/lock.h>
50 #include <sys/malloc.h>
51 #include <sys/mount.h>
52 #include <sys/mutex.h>
53 #include <sys/unistd.h>
54 #include <sys/vnode.h>
55 #include <sys/poll.h>
56 
57 #include <vm/vm.h>
58 #include <vm/vm_object.h>
59 #include <vm/vm_extern.h>
60 #include <vm/pmap.h>
61 #include <vm/vm_map.h>
62 #include <vm/vm_page.h>
63 #include <vm/vm_pager.h>
64 #include <vm/vnode_pager.h>
65 
66 static int	vop_nolookup(struct vop_lookup_args *);
67 static int	vop_nostrategy(struct vop_strategy_args *);
68 
69 /*
70  * This vnode table stores what we want to do if the filesystem doesn't
71  * implement a particular VOP.
72  *
73  * If there is no specific entry here, we will return EOPNOTSUPP.
74  *
75  */
76 
77 vop_t **default_vnodeop_p;
78 static struct vnodeopv_entry_desc default_vnodeop_entries[] = {
79 	{ &vop_default_desc,		(vop_t *) vop_eopnotsupp },
80 	{ &vop_advlock_desc,		(vop_t *) vop_einval },
81 	{ &vop_bmap_desc,		(vop_t *) vop_stdbmap },
82 	{ &vop_close_desc,		(vop_t *) vop_null },
83 	{ &vop_createvobject_desc,	(vop_t *) vop_stdcreatevobject },
84 	{ &vop_destroyvobject_desc,	(vop_t *) vop_stddestroyvobject },
85 	{ &vop_fsync_desc,		(vop_t *) vop_null },
86 	{ &vop_getpages_desc,		(vop_t *) vop_stdgetpages },
87 	{ &vop_getvobject_desc,		(vop_t *) vop_stdgetvobject },
88 	{ &vop_inactive_desc,		(vop_t *) vop_stdinactive },
89 	{ &vop_ioctl_desc,		(vop_t *) vop_enotty },
90 	{ &vop_islocked_desc,		(vop_t *) vop_stdislocked },
91 	{ &vop_lease_desc,		(vop_t *) vop_null },
92 	{ &vop_lock_desc,		(vop_t *) vop_stdlock },
93 	{ &vop_lookup_desc,		(vop_t *) vop_nolookup },
94 	{ &vop_open_desc,		(vop_t *) vop_null },
95 	{ &vop_pathconf_desc,		(vop_t *) vop_einval },
96 	{ &vop_poll_desc,		(vop_t *) vop_nopoll },
97 	{ &vop_putpages_desc,		(vop_t *) vop_stdputpages },
98 	{ &vop_readlink_desc,		(vop_t *) vop_einval },
99 	{ &vop_revoke_desc,		(vop_t *) vop_revoke },
100 	{ &vop_specstrategy_desc,	(vop_t *) vop_panic },
101 	{ &vop_strategy_desc,		(vop_t *) vop_nostrategy },
102 	{ &vop_unlock_desc,		(vop_t *) vop_stdunlock },
103 	{ NULL, NULL }
104 };
105 
106 static struct vnodeopv_desc default_vnodeop_opv_desc =
107         { &default_vnodeop_p, default_vnodeop_entries };
108 
109 VNODEOP_SET(default_vnodeop_opv_desc);
110 
111 /*
112  * Series of placeholder functions for various error returns for
113  * VOPs.
114  */
115 
116 int
117 vop_eopnotsupp(struct vop_generic_args *ap)
118 {
119 	/*
120 	printf("vop_notsupp[%s]\n", ap->a_desc->vdesc_name);
121 	*/
122 
123 	return (EOPNOTSUPP);
124 }
125 
126 int
127 vop_ebadf(struct vop_generic_args *ap)
128 {
129 
130 	return (EBADF);
131 }
132 
133 int
134 vop_enotty(struct vop_generic_args *ap)
135 {
136 
137 	return (ENOTTY);
138 }
139 
140 int
141 vop_einval(struct vop_generic_args *ap)
142 {
143 
144 	return (EINVAL);
145 }
146 
147 int
148 vop_null(struct vop_generic_args *ap)
149 {
150 
151 	return (0);
152 }
153 
154 /*
155  * Used to make a defined VOP fall back to the default VOP.
156  */
157 int
158 vop_defaultop(struct vop_generic_args *ap)
159 {
160 
161 	return (VOCALL(default_vnodeop_p, ap->a_desc->vdesc_offset, ap));
162 }
163 
164 /*
165  * Helper function to panic on some bad VOPs in some filesystems.
166  */
167 int
168 vop_panic(struct vop_generic_args *ap)
169 {
170 
171 	panic("filesystem goof: vop_panic[%s]", ap->a_desc->vdesc_name);
172 }
173 
174 /*
175  * vop_std<something> and vop_no<something> are default functions for use by
176  * filesystems that need the "default reasonable" implementation for a
177  * particular operation.
178  *
179  * The documentation for the operations they implement exists (if it exists)
180  * in the VOP_<SOMETHING>(9) manpage (all uppercase).
181  */
182 
183 /*
184  * Default vop for filesystems that do not support name lookup
185  */
186 static int
187 vop_nolookup(ap)
188 	struct vop_lookup_args /* {
189 		struct vnode *a_dvp;
190 		struct vnode **a_vpp;
191 		struct componentname *a_cnp;
192 	} */ *ap;
193 {
194 
195 	*ap->a_vpp = NULL;
196 	return (ENOTDIR);
197 }
198 
199 /*
200  *	vop_nostrategy:
201  *
202  *	Strategy routine for VFS devices that have none.
203  *
204  *	BIO_ERROR and B_INVAL must be cleared prior to calling any strategy
205  *	routine.  Typically this is done for a BIO_READ strategy call.
206  *	Typically B_INVAL is assumed to already be clear prior to a write
207  *	and should not be cleared manually unless you just made the buffer
208  *	invalid.  BIO_ERROR should be cleared either way.
209  */
210 
211 static int
212 vop_nostrategy (struct vop_strategy_args *ap)
213 {
214 	KASSERT(ap->a_vp == ap->a_bp->b_vp, ("%s(%p != %p)",
215 	    __func__, ap->a_vp, ap->a_bp->b_vp));
216 	printf("No strategy for buffer at %p\n", ap->a_bp);
217 	vprint("vnode", ap->a_vp);
218 	vprint("device vnode", ap->a_bp->b_vp);
219 	ap->a_bp->b_ioflags |= BIO_ERROR;
220 	ap->a_bp->b_error = EOPNOTSUPP;
221 	bufdone(ap->a_bp);
222 	return (EOPNOTSUPP);
223 }
224 
225 /*
226  * vop_stdpathconf:
227  *
228  * Standard implementation of POSIX pathconf, to get information about limits
229  * for a filesystem.
230  * Override per filesystem for the case where the filesystem has smaller
231  * limits.
232  */
233 int
234 vop_stdpathconf(ap)
235 	struct vop_pathconf_args /* {
236 	struct vnode *a_vp;
237 	int a_name;
238 	int *a_retval;
239 	} */ *ap;
240 {
241 
242 	switch (ap->a_name) {
243 		case _PC_LINK_MAX:
244 			*ap->a_retval = LINK_MAX;
245 			return (0);
246 		case _PC_MAX_CANON:
247 			*ap->a_retval = MAX_CANON;
248 			return (0);
249 		case _PC_MAX_INPUT:
250 			*ap->a_retval = MAX_INPUT;
251 			return (0);
252 		case _PC_PIPE_BUF:
253 			*ap->a_retval = PIPE_BUF;
254 			return (0);
255 		case _PC_CHOWN_RESTRICTED:
256 			*ap->a_retval = 1;
257 			return (0);
258 		case _PC_VDISABLE:
259 			*ap->a_retval = _POSIX_VDISABLE;
260 			return (0);
261 		default:
262 			return (EINVAL);
263 	}
264 	/* NOTREACHED */
265 }
266 
267 /*
268  * Standard lock, unlock and islocked functions.
269  */
270 int
271 vop_stdlock(ap)
272 	struct vop_lock_args /* {
273 		struct vnode *a_vp;
274 		int a_flags;
275 		struct thread *a_td;
276 	} */ *ap;
277 {
278 	struct vnode *vp = ap->a_vp;
279 
280 #ifndef	DEBUG_LOCKS
281 	return (lockmgr(vp->v_vnlock, ap->a_flags, VI_MTX(vp), ap->a_td));
282 #else
283 	return (debuglockmgr(vp->v_vnlock, ap->a_flags, VI_MTX(vp),
284 	    ap->a_td, "vop_stdlock", vp->filename, vp->line));
285 #endif
286 }
287 
288 /* See above. */
289 int
290 vop_stdunlock(ap)
291 	struct vop_unlock_args /* {
292 		struct vnode *a_vp;
293 		int a_flags;
294 		struct thread *a_td;
295 	} */ *ap;
296 {
297 	struct vnode *vp = ap->a_vp;
298 
299 	return (lockmgr(vp->v_vnlock, ap->a_flags | LK_RELEASE, VI_MTX(vp),
300 	    ap->a_td));
301 }
302 
303 /* See above. */
304 int
305 vop_stdislocked(ap)
306 	struct vop_islocked_args /* {
307 		struct vnode *a_vp;
308 		struct thread *a_td;
309 	} */ *ap;
310 {
311 
312 	return (lockstatus(ap->a_vp->v_vnlock, ap->a_td));
313 }
314 
315 /* Mark the vnode inactive */
316 int
317 vop_stdinactive(ap)
318 	struct vop_inactive_args /* {
319 		struct vnode *a_vp;
320 		struct thread *a_td;
321 	} */ *ap;
322 {
323 
324 	VOP_UNLOCK(ap->a_vp, 0, ap->a_td);
325 	return (0);
326 }
327 
328 /*
329  * Return true for select/poll.
330  */
331 int
332 vop_nopoll(ap)
333 	struct vop_poll_args /* {
334 		struct vnode *a_vp;
335 		int  a_events;
336 		struct ucred *a_cred;
337 		struct thread *a_td;
338 	} */ *ap;
339 {
340 	/*
341 	 * Return true for read/write.  If the user asked for something
342 	 * special, return POLLNVAL, so that clients have a way of
343 	 * determining reliably whether or not the extended
344 	 * functionality is present without hard-coding knowledge
345 	 * of specific filesystem implementations.
346 	 * Stay in sync with kern_conf.c::no_poll().
347 	 */
348 	if (ap->a_events & ~POLLSTANDARD)
349 		return (POLLNVAL);
350 
351 	return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
352 }
353 
354 /*
355  * Implement poll for local filesystems that support it.
356  */
357 int
358 vop_stdpoll(ap)
359 	struct vop_poll_args /* {
360 		struct vnode *a_vp;
361 		int  a_events;
362 		struct ucred *a_cred;
363 		struct thread *a_td;
364 	} */ *ap;
365 {
366 	if (ap->a_events & ~POLLSTANDARD)
367 		return (vn_pollrecord(ap->a_vp, ap->a_td, ap->a_events));
368 	return (ap->a_events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
369 }
370 
371 /*
372  * Return our mount point, as we will take charge of the writes.
373  */
374 int
375 vop_stdgetwritemount(ap)
376 	struct vop_getwritemount_args /* {
377 		struct vnode *a_vp;
378 		struct mount **a_mpp;
379 	} */ *ap;
380 {
381 
382 	*(ap->a_mpp) = ap->a_vp->v_mount;
383 	return (0);
384 }
385 
386 /* Create the VM system backing object for this vnode */
387 int
388 vop_stdcreatevobject(ap)
389 	struct vop_createvobject_args /* {
390 		struct vnode *vp;
391 		struct ucred *cred;
392 		struct thread *td;
393 	} */ *ap;
394 {
395 	struct vnode *vp = ap->a_vp;
396 	struct ucred *cred = ap->a_cred;
397 	struct thread *td = ap->a_td;
398 	struct vattr vat;
399 	vm_object_t object;
400 	int error = 0;
401 
402 	GIANT_REQUIRED;
403 
404 	if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE)
405 		return (0);
406 
407 retry:
408 	if ((object = vp->v_object) == NULL) {
409 		if (vp->v_type == VREG || vp->v_type == VDIR) {
410 			if ((error = VOP_GETATTR(vp, &vat, cred, td)) != 0)
411 				goto retn;
412 			object = vnode_pager_alloc(vp, vat.va_size, 0, 0);
413 		} else if (devsw(vp->v_rdev) != NULL) {
414 			/*
415 			 * This simply allocates the biggest object possible
416 			 * for a disk vnode.  This should be fixed, but doesn't
417 			 * cause any problems (yet).
418 			 */
419 			object = vnode_pager_alloc(vp, IDX_TO_OFF(INT_MAX), 0, 0);
420 		} else {
421 			goto retn;
422 		}
423 		/*
424 		 * Dereference the reference we just created.  This assumes
425 		 * that the object is associated with the vp.
426 		 */
427 		VM_OBJECT_LOCK(object);
428 		object->ref_count--;
429 		VM_OBJECT_UNLOCK(object);
430 		vrele(vp);
431 	} else {
432 		VM_OBJECT_LOCK(object);
433 		if (object->flags & OBJ_DEAD) {
434 			VOP_UNLOCK(vp, 0, td);
435 			msleep(object, VM_OBJECT_MTX(object), PDROP | PVM,
436 			    "vodead", 0);
437 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
438 			goto retry;
439 		}
440 		VM_OBJECT_UNLOCK(object);
441 	}
442 
443 	KASSERT(vp->v_object != NULL, ("vfs_object_create: NULL object"));
444 	vp->v_vflag |= VV_OBJBUF;
445 
446 retn:
447 	return (error);
448 }
449 
450 /* Destroy the VM system object associated with this vnode */
451 int
452 vop_stddestroyvobject(ap)
453 	struct vop_destroyvobject_args /* {
454 		struct vnode *vp;
455 	} */ *ap;
456 {
457 	struct vnode *vp = ap->a_vp;
458 	vm_object_t obj = vp->v_object;
459 
460 	GIANT_REQUIRED;
461 
462 	if (obj == NULL)
463 		return (0);
464 	VM_OBJECT_LOCK(obj);
465 	if (obj->ref_count == 0) {
466 		/*
467 		 * vclean() may be called twice. The first time
468 		 * removes the primary reference to the object,
469 		 * the second time goes one further and is a
470 		 * special-case to terminate the object.
471 		 *
472 		 * don't double-terminate the object
473 		 */
474 		if ((obj->flags & OBJ_DEAD) == 0)
475 			vm_object_terminate(obj);
476 		else
477 			VM_OBJECT_UNLOCK(obj);
478 	} else {
479 		/*
480 		 * Woe to the process that tries to page now :-).
481 		 */
482 		vm_pager_deallocate(obj);
483 		VM_OBJECT_UNLOCK(obj);
484 	}
485 	return (0);
486 }
487 
488 /*
489  * Return the underlying VM object.  This routine may be called with or
490  * without the vnode interlock held.  If called without, the returned
491  * object is not guarenteed to be valid.  The syncer typically gets the
492  * object without holding the interlock in order to quickly test whether
493  * it might be dirty before going heavy-weight.  vm_object's use zalloc
494  * and thus stable-storage, so this is safe.
495  */
496 int
497 vop_stdgetvobject(ap)
498 	struct vop_getvobject_args /* {
499 		struct vnode *vp;
500 		struct vm_object **objpp;
501 	} */ *ap;
502 {
503 	struct vnode *vp = ap->a_vp;
504 	struct vm_object **objpp = ap->a_objpp;
505 
506 	if (objpp)
507 		*objpp = vp->v_object;
508 	return (vp->v_object ? 0 : EINVAL);
509 }
510 
511 /* XXX Needs good comment and VOP_BMAP(9) manpage */
512 int
513 vop_stdbmap(ap)
514 	struct vop_bmap_args /* {
515 		struct vnode *a_vp;
516 		daddr_t  a_bn;
517 		struct vnode **a_vpp;
518 		daddr_t *a_bnp;
519 		int *a_runp;
520 		int *a_runb;
521 	} */ *ap;
522 {
523 
524 	if (ap->a_vpp != NULL)
525 		*ap->a_vpp = ap->a_vp;
526 	if (ap->a_bnp != NULL)
527 		*ap->a_bnp = ap->a_bn * btodb(ap->a_vp->v_mount->mnt_stat.f_iosize);
528 	if (ap->a_runp != NULL)
529 		*ap->a_runp = 0;
530 	if (ap->a_runb != NULL)
531 		*ap->a_runb = 0;
532 	return (0);
533 }
534 
535 int
536 vop_stdfsync(ap)
537 	struct vop_fsync_args /* {
538 		struct vnode *a_vp;
539 		struct ucred *a_cred;
540 		int a_waitfor;
541 		struct thread *a_td;
542 	} */ *ap;
543 {
544 	struct vnode *vp = ap->a_vp;
545 	struct buf *bp;
546 	struct buf *nbp;
547 	int s, error = 0;
548 	int maxretry = 100;     /* large, arbitrarily chosen */
549 
550 	VI_LOCK(vp);
551 loop1:
552 	/*
553 	 * MARK/SCAN initialization to avoid infinite loops.
554 	 */
555 	s = splbio();
556         TAILQ_FOREACH(bp, &vp->v_dirtyblkhd, b_vnbufs) {
557                 bp->b_vflags &= ~BV_SCANNED;
558 		bp->b_error = 0;
559 	}
560 	splx(s);
561 
562 	/*
563 	 * Flush all dirty buffers associated with a block device.
564 	 */
565 loop2:
566 	s = splbio();
567 	for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp != NULL; bp = nbp) {
568 		nbp = TAILQ_NEXT(bp, b_vnbufs);
569 		if ((bp->b_vflags & BV_SCANNED) != 0)
570 			continue;
571 		bp->b_vflags |= BV_SCANNED;
572 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT, NULL))
573 			continue;
574 		VI_UNLOCK(vp);
575 		if ((bp->b_flags & B_DELWRI) == 0)
576 			panic("fsync: not dirty");
577 		if ((vp->v_vflag & VV_OBJBUF) && (bp->b_flags & B_CLUSTEROK)) {
578 			vfs_bio_awrite(bp);
579 			splx(s);
580 		} else {
581 			bremfree(bp);
582 			splx(s);
583 			bawrite(bp);
584 		}
585 		VI_LOCK(vp);
586 		goto loop2;
587 	}
588 
589 	/*
590 	 * If synchronous the caller expects us to completely resolve all
591 	 * dirty buffers in the system.  Wait for in-progress I/O to
592 	 * complete (which could include background bitmap writes), then
593 	 * retry if dirty blocks still exist.
594 	 */
595 	if (ap->a_waitfor == MNT_WAIT) {
596 		while (vp->v_numoutput) {
597 			vp->v_iflag |= VI_BWAIT;
598 			msleep((caddr_t)&vp->v_numoutput, VI_MTX(vp),
599 			    PRIBIO + 1, "fsync", 0);
600 		}
601 		if (!TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
602 			/*
603 			 * If we are unable to write any of these buffers
604 			 * then we fail now rather than trying endlessly
605 			 * to write them out.
606 			 */
607 			TAILQ_FOREACH(bp, &vp->v_dirtyblkhd, b_vnbufs)
608 				if ((error = bp->b_error) == 0)
609 					continue;
610 			if (error == 0 && --maxretry >= 0) {
611 				splx(s);
612 				goto loop1;
613 			}
614 			vprint("fsync: giving up on dirty", vp);
615 			error = EAGAIN;
616 		}
617 	}
618 	VI_UNLOCK(vp);
619 	splx(s);
620 
621 	return (error);
622 }
623 
624 /* XXX Needs good comment and more info in the manpage (VOP_GETPAGES(9)). */
625 int
626 vop_stdgetpages(ap)
627 	struct vop_getpages_args /* {
628 		struct vnode *a_vp;
629 		vm_page_t *a_m;
630 		int a_count;
631 		int a_reqpage;
632 		vm_ooffset_t a_offset;
633 	} */ *ap;
634 {
635 
636 	return vnode_pager_generic_getpages(ap->a_vp, ap->a_m,
637 	    ap->a_count, ap->a_reqpage);
638 }
639 
640 /* XXX Needs good comment and more info in the manpage (VOP_PUTPAGES(9)). */
641 int
642 vop_stdputpages(ap)
643 	struct vop_putpages_args /* {
644 		struct vnode *a_vp;
645 		vm_page_t *a_m;
646 		int a_count;
647 		int a_sync;
648 		int *a_rtvals;
649 		vm_ooffset_t a_offset;
650 	} */ *ap;
651 {
652 
653 	return vnode_pager_generic_putpages(ap->a_vp, ap->a_m, ap->a_count,
654 	     ap->a_sync, ap->a_rtvals);
655 }
656 
657 /*
658  * vfs default ops
659  * used to fill the vfs function table to get reasonable default return values.
660  */
661 int
662 vfs_stdroot (mp, vpp)
663 	struct mount *mp;
664 	struct vnode **vpp;
665 {
666 	return (EOPNOTSUPP);
667 }
668 
669 int
670 vfs_stdstatfs (mp, sbp, td)
671 	struct mount *mp;
672 	struct statfs *sbp;
673 	struct thread *td;
674 {
675 	return (EOPNOTSUPP);
676 }
677 
678 int
679 vfs_stdvptofh (vp, fhp)
680 	struct vnode *vp;
681 	struct fid *fhp;
682 {
683 	return (EOPNOTSUPP);
684 }
685 
686 int
687 vfs_stdstart (mp, flags, td)
688 	struct mount *mp;
689 	int flags;
690 	struct thread *td;
691 {
692 	return (0);
693 }
694 
695 int
696 vfs_stdquotactl (mp, cmds, uid, arg, td)
697 	struct mount *mp;
698 	int cmds;
699 	uid_t uid;
700 	caddr_t arg;
701 	struct thread *td;
702 {
703 	return (EOPNOTSUPP);
704 }
705 
706 int
707 vfs_stdsync(mp, waitfor, cred, td)
708 	struct mount *mp;
709 	int waitfor;
710 	struct ucred *cred;
711 	struct thread *td;
712 {
713 	struct vnode *vp, *nvp;
714 	int error, lockreq, allerror = 0;
715 
716 	lockreq = LK_EXCLUSIVE | LK_INTERLOCK;
717 	if (waitfor != MNT_WAIT)
718 		lockreq |= LK_NOWAIT;
719 	/*
720 	 * Force stale buffer cache information to be flushed.
721 	 */
722 	MNT_ILOCK(mp);
723 loop:
724 	for (vp = TAILQ_FIRST(&mp->mnt_nvnodelist); vp != NULL; vp = nvp) {
725 		/*
726 		 * If the vnode that we are about to sync is no longer
727 		 * associated with this mount point, start over.
728 		 */
729 		if (vp->v_mount != mp)
730 			goto loop;
731 
732 		nvp = TAILQ_NEXT(vp, v_nmntvnodes);
733 
734 		VI_LOCK(vp);
735 		if (TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
736 			VI_UNLOCK(vp);
737 			continue;
738 		}
739 		MNT_IUNLOCK(mp);
740 
741 		if ((error = vget(vp, lockreq, td)) != 0) {
742 			MNT_ILOCK(mp);
743 			if (error == ENOENT)
744 				goto loop;
745 			continue;
746 		}
747 		error = VOP_FSYNC(vp, cred, waitfor, td);
748 		if (error)
749 			allerror = error;
750 
751 		VOP_UNLOCK(vp, 0, td);
752 		vrele(vp);
753 		MNT_ILOCK(mp);
754 	}
755 	MNT_IUNLOCK(mp);
756 	return (allerror);
757 }
758 
759 int
760 vfs_stdnosync (mp, waitfor, cred, td)
761 	struct mount *mp;
762 	int waitfor;
763 	struct ucred *cred;
764 	struct thread *td;
765 {
766 	return (0);
767 }
768 
769 int
770 vfs_stdvget (mp, ino, flags, vpp)
771 	struct mount *mp;
772 	ino_t ino;
773 	int flags;
774 	struct vnode **vpp;
775 {
776 	return (EOPNOTSUPP);
777 }
778 
779 int
780 vfs_stdfhtovp (mp, fhp, vpp)
781 	struct mount *mp;
782 	struct fid *fhp;
783 	struct vnode **vpp;
784 {
785 	return (EOPNOTSUPP);
786 }
787 
788 int
789 vfs_stdinit (vfsp)
790 	struct vfsconf *vfsp;
791 {
792 	return (0);
793 }
794 
795 int
796 vfs_stduninit (vfsp)
797 	struct vfsconf *vfsp;
798 {
799 	return(0);
800 }
801 
802 int
803 vfs_stdextattrctl(mp, cmd, filename_vp, attrnamespace, attrname, td)
804 	struct mount *mp;
805 	int cmd;
806 	struct vnode *filename_vp;
807 	int attrnamespace;
808 	const char *attrname;
809 	struct thread *td;
810 {
811 	if (filename_vp != NULL)
812 		VOP_UNLOCK(filename_vp, 0, td);
813 	return(EOPNOTSUPP);
814 }
815 
816 /* end of vfs default ops */
817