xref: /dragonfly/sys/kern/vfs_subr.c (revision 1847e88f)
1 /*
2  * Copyright (c) 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
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  *	@(#)vfs_subr.c	8.31 (Berkeley) 5/26/95
39  * $FreeBSD: src/sys/kern/vfs_subr.c,v 1.249.2.30 2003/04/04 20:35:57 tegge Exp $
40  * $DragonFly: src/sys/kern/vfs_subr.c,v 1.66 2006/02/17 19:18:06 dillon Exp $
41  */
42 
43 /*
44  * External virtual filesystem routines
45  */
46 #include "opt_ddb.h"
47 
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/buf.h>
51 #include <sys/conf.h>
52 #include <sys/dirent.h>
53 #include <sys/domain.h>
54 #include <sys/eventhandler.h>
55 #include <sys/fcntl.h>
56 #include <sys/kernel.h>
57 #include <sys/kthread.h>
58 #include <sys/malloc.h>
59 #include <sys/mbuf.h>
60 #include <sys/mount.h>
61 #include <sys/proc.h>
62 #include <sys/reboot.h>
63 #include <sys/socket.h>
64 #include <sys/stat.h>
65 #include <sys/sysctl.h>
66 #include <sys/syslog.h>
67 #include <sys/unistd.h>
68 #include <sys/vmmeter.h>
69 #include <sys/vnode.h>
70 
71 #include <machine/limits.h>
72 
73 #include <vm/vm.h>
74 #include <vm/vm_object.h>
75 #include <vm/vm_extern.h>
76 #include <vm/vm_kern.h>
77 #include <vm/pmap.h>
78 #include <vm/vm_map.h>
79 #include <vm/vm_page.h>
80 #include <vm/vm_pager.h>
81 #include <vm/vnode_pager.h>
82 #include <vm/vm_zone.h>
83 
84 #include <sys/buf2.h>
85 #include <sys/thread2.h>
86 
87 static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
88 
89 int numvnodes;
90 SYSCTL_INT(_debug, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0, "");
91 int vfs_fastdev = 1;
92 SYSCTL_INT(_vfs, OID_AUTO, fastdev, CTLFLAG_RW, &vfs_fastdev, 0, "");
93 
94 enum vtype iftovt_tab[16] = {
95 	VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
96 	VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
97 };
98 int vttoif_tab[9] = {
99 	0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
100 	S_IFSOCK, S_IFIFO, S_IFMT,
101 };
102 
103 static int reassignbufcalls;
104 SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW,
105 		&reassignbufcalls, 0, "");
106 static int reassignbufloops;
107 SYSCTL_INT(_vfs, OID_AUTO, reassignbufloops, CTLFLAG_RW,
108 		&reassignbufloops, 0, "");
109 static int reassignbufsortgood;
110 SYSCTL_INT(_vfs, OID_AUTO, reassignbufsortgood, CTLFLAG_RW,
111 		&reassignbufsortgood, 0, "");
112 static int reassignbufsortbad;
113 SYSCTL_INT(_vfs, OID_AUTO, reassignbufsortbad, CTLFLAG_RW,
114 		&reassignbufsortbad, 0, "");
115 static int reassignbufmethod = 1;
116 SYSCTL_INT(_vfs, OID_AUTO, reassignbufmethod, CTLFLAG_RW,
117 		&reassignbufmethod, 0, "");
118 
119 int	nfs_mount_type = -1;
120 static struct lwkt_token spechash_token;
121 struct nfs_public nfs_pub;	/* publicly exported FS */
122 
123 int desiredvnodes;
124 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
125 		&desiredvnodes, 0, "Maximum number of vnodes");
126 
127 static void	vfs_free_addrlist (struct netexport *nep);
128 static int	vfs_free_netcred (struct radix_node *rn, void *w);
129 static int	vfs_hang_addrlist (struct mount *mp, struct netexport *nep,
130 				       struct export_args *argp);
131 
132 extern int dev_ref_debug;
133 extern struct vnodeopv_entry_desc spec_vnodeop_entries[];
134 
135 /*
136  * Red black tree functions
137  */
138 static int rb_buf_compare(struct buf *b1, struct buf *b2);
139 RB_GENERATE(buf_rb_tree, buf, b_rbnode, rb_buf_compare);
140 
141 static int
142 rb_buf_compare(struct buf *b1, struct buf *b2)
143 {
144 	if (b1->b_lblkno < b2->b_lblkno)
145 		return(-1);
146 	if (b1->b_lblkno > b2->b_lblkno)
147 		return(1);
148 	return(0);
149 }
150 
151 /*
152  * Return 0 if the vnode is already on the free list or cannot be placed
153  * on the free list.  Return 1 if the vnode can be placed on the free list.
154  */
155 static __inline int
156 vshouldfree(struct vnode *vp, int usecount)
157 {
158 	if (vp->v_flag & VFREE)
159 		return (0);		/* already free */
160 	if (vp->v_holdcnt != 0 || vp->v_usecount != usecount)
161 		return (0);		/* other holderse */
162 	if (vp->v_object &&
163 	    (vp->v_object->ref_count || vp->v_object->resident_page_count)) {
164 		return (0);
165 	}
166 	return (1);
167 }
168 
169 /*
170  * Initialize the vnode management data structures.
171  *
172  * Called from vfsinit()
173  */
174 void
175 vfs_subr_init(void)
176 {
177 	/*
178 	 * Desired vnodes is a result of the physical page count
179 	 * and the size of kernel's heap.  It scales in proportion
180 	 * to the amount of available physical memory.  This can
181 	 * cause trouble on 64-bit and large memory platforms.
182 	 */
183 	/* desiredvnodes = maxproc + vmstats.v_page_count / 4; */
184 	desiredvnodes =
185 		min(maxproc + vmstats.v_page_count /4,
186 		    2 * (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) /
187 		    (5 * (sizeof(struct vm_object) + sizeof(struct vnode))));
188 
189 	lwkt_token_init(&spechash_token);
190 }
191 
192 /*
193  * Knob to control the precision of file timestamps:
194  *
195  *   0 = seconds only; nanoseconds zeroed.
196  *   1 = seconds and nanoseconds, accurate within 1/HZ.
197  *   2 = seconds and nanoseconds, truncated to microseconds.
198  * >=3 = seconds and nanoseconds, maximum precision.
199  */
200 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
201 
202 static int timestamp_precision = TSP_SEC;
203 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
204 		&timestamp_precision, 0, "");
205 
206 /*
207  * Get a current timestamp.
208  */
209 void
210 vfs_timestamp(struct timespec *tsp)
211 {
212 	struct timeval tv;
213 
214 	switch (timestamp_precision) {
215 	case TSP_SEC:
216 		tsp->tv_sec = time_second;
217 		tsp->tv_nsec = 0;
218 		break;
219 	case TSP_HZ:
220 		getnanotime(tsp);
221 		break;
222 	case TSP_USEC:
223 		microtime(&tv);
224 		TIMEVAL_TO_TIMESPEC(&tv, tsp);
225 		break;
226 	case TSP_NSEC:
227 	default:
228 		nanotime(tsp);
229 		break;
230 	}
231 }
232 
233 /*
234  * Set vnode attributes to VNOVAL
235  */
236 void
237 vattr_null(struct vattr *vap)
238 {
239 	vap->va_type = VNON;
240 	vap->va_size = VNOVAL;
241 	vap->va_bytes = VNOVAL;
242 	vap->va_mode = VNOVAL;
243 	vap->va_nlink = VNOVAL;
244 	vap->va_uid = VNOVAL;
245 	vap->va_gid = VNOVAL;
246 	vap->va_fsid = VNOVAL;
247 	vap->va_fileid = VNOVAL;
248 	vap->va_blocksize = VNOVAL;
249 	vap->va_rdev = VNOVAL;
250 	vap->va_atime.tv_sec = VNOVAL;
251 	vap->va_atime.tv_nsec = VNOVAL;
252 	vap->va_mtime.tv_sec = VNOVAL;
253 	vap->va_mtime.tv_nsec = VNOVAL;
254 	vap->va_ctime.tv_sec = VNOVAL;
255 	vap->va_ctime.tv_nsec = VNOVAL;
256 	vap->va_flags = VNOVAL;
257 	vap->va_gen = VNOVAL;
258 	vap->va_vaflags = 0;
259 	vap->va_fsmid = VNOVAL;
260 }
261 
262 /*
263  * Flush out and invalidate all buffers associated with a vnode.
264  *
265  * vp must be locked.
266  */
267 static int vinvalbuf_bp(struct buf *bp, void *data);
268 
269 struct vinvalbuf_bp_info {
270 	struct vnode *vp;
271 	int slptimeo;
272 	int slpflag;
273 	int flags;
274 };
275 
276 int
277 vinvalbuf(struct vnode *vp, int flags, struct thread *td,
278 	int slpflag, int slptimeo)
279 {
280 	struct vinvalbuf_bp_info info;
281 	int error;
282 	vm_object_t object;
283 
284 	/*
285 	 * If we are being asked to save, call fsync to ensure that the inode
286 	 * is updated.
287 	 */
288 	if (flags & V_SAVE) {
289 		crit_enter();
290 		while (vp->v_track_write.bk_active) {
291 			vp->v_track_write.bk_waitflag = 1;
292 			error = tsleep(&vp->v_track_write, slpflag,
293 					"vinvlbuf", slptimeo);
294 			if (error) {
295 				crit_exit();
296 				return (error);
297 			}
298 		}
299 		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
300 			crit_exit();
301 			if ((error = VOP_FSYNC(vp, MNT_WAIT, td)) != 0)
302 				return (error);
303 			crit_enter();
304 			if (vp->v_track_write.bk_active > 0 ||
305 			    !RB_EMPTY(&vp->v_rbdirty_tree))
306 				panic("vinvalbuf: dirty bufs");
307 		}
308 		crit_exit();
309   	}
310 	crit_enter();
311 	info.slptimeo = slptimeo;
312 	info.slpflag = slpflag;
313 	info.flags = flags;
314 	info.vp = vp;
315 
316 	/*
317 	 * Flush the buffer cache until nothing is left.
318 	 */
319 	while (!RB_EMPTY(&vp->v_rbclean_tree) ||
320 	    !RB_EMPTY(&vp->v_rbdirty_tree)) {
321 		error = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree, NULL,
322 			vinvalbuf_bp, &info);
323 		if (error == 0) {
324 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
325 					vinvalbuf_bp, &info);
326 		}
327 	}
328 
329 	/*
330 	 * Wait for I/O to complete.  XXX needs cleaning up.  The vnode can
331 	 * have write I/O in-progress but if there is a VM object then the
332 	 * VM object can also have read-I/O in-progress.
333 	 */
334 	do {
335 		while (vp->v_track_write.bk_active > 0) {
336 			vp->v_track_write.bk_waitflag = 1;
337 			tsleep(&vp->v_track_write, 0, "vnvlbv", 0);
338 		}
339 		if (VOP_GETVOBJECT(vp, &object) == 0) {
340 			while (object->paging_in_progress)
341 				vm_object_pip_sleep(object, "vnvlbx");
342 		}
343 	} while (vp->v_track_write.bk_active > 0);
344 
345 	crit_exit();
346 
347 	/*
348 	 * Destroy the copy in the VM cache, too.
349 	 */
350 	if (VOP_GETVOBJECT(vp, &object) == 0) {
351 		vm_object_page_remove(object, 0, 0,
352 			(flags & V_SAVE) ? TRUE : FALSE);
353 	}
354 
355 	if (!RB_EMPTY(&vp->v_rbdirty_tree) || !RB_EMPTY(&vp->v_rbclean_tree))
356 		panic("vinvalbuf: flush failed");
357 	return (0);
358 }
359 
360 static int
361 vinvalbuf_bp(struct buf *bp, void *data)
362 {
363 	struct vinvalbuf_bp_info *info = data;
364 	int error;
365 
366 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
367 		error = BUF_TIMELOCK(bp,
368 		    LK_EXCLUSIVE | LK_SLEEPFAIL,
369 		    "vinvalbuf", info->slpflag, info->slptimeo);
370 		if (error == 0) {
371 			BUF_UNLOCK(bp);
372 			error = ENOLCK;
373 		}
374 		if (error == ENOLCK)
375 			return(0);
376 		return (-error);
377 	}
378 	/*
379 	 * XXX Since there are no node locks for NFS, I
380 	 * believe there is a slight chance that a delayed
381 	 * write will occur while sleeping just above, so
382 	 * check for it.  Note that vfs_bio_awrite expects
383 	 * buffers to reside on a queue, while VOP_BWRITE and
384 	 * brelse do not.
385 	 */
386 	if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
387 	    (info->flags & V_SAVE)) {
388 		if (bp->b_vp == info->vp) {
389 			if (bp->b_flags & B_CLUSTEROK) {
390 				BUF_UNLOCK(bp);
391 				vfs_bio_awrite(bp);
392 			} else {
393 				bremfree(bp);
394 				bp->b_flags |= B_ASYNC;
395 				VOP_BWRITE(bp->b_vp, bp);
396 			}
397 		} else {
398 			bremfree(bp);
399 			VOP_BWRITE(bp->b_vp, bp);
400 		}
401 	} else {
402 		bremfree(bp);
403 		bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
404 		bp->b_flags &= ~B_ASYNC;
405 		brelse(bp);
406 	}
407 	return(0);
408 }
409 
410 /*
411  * Truncate a file's buffer and pages to a specified length.  This
412  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
413  * sync activity.
414  *
415  * The vnode must be locked.
416  */
417 static int vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data);
418 static int vtruncbuf_bp_trunc(struct buf *bp, void *data);
419 static int vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data);
420 static int vtruncbuf_bp_metasync(struct buf *bp, void *data);
421 
422 int
423 vtruncbuf(struct vnode *vp, struct thread *td, off_t length, int blksize)
424 {
425 	daddr_t trunclbn;
426 	int count;
427 
428 	/*
429 	 * Round up to the *next* lbn, then destroy the buffers in question.
430 	 * Since we are only removing some of the buffers we must rely on the
431 	 * scan count to determine whether a loop is necessary.
432 	 */
433 	trunclbn = (length + blksize - 1) / blksize;
434 
435 	crit_enter();
436 	do {
437 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
438 				vtruncbuf_bp_trunc_cmp,
439 				vtruncbuf_bp_trunc, &trunclbn);
440 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
441 				vtruncbuf_bp_trunc_cmp,
442 				vtruncbuf_bp_trunc, &trunclbn);
443 	} while(count);
444 
445 	/*
446 	 * For safety, fsync any remaining metadata if the file is not being
447 	 * truncated to 0.  Since the metadata does not represent the entire
448 	 * dirty list we have to rely on the hit count to ensure that we get
449 	 * all of it.
450 	 */
451 	if (length > 0) {
452 		do {
453 			count = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
454 					vtruncbuf_bp_metasync_cmp,
455 					vtruncbuf_bp_metasync, vp);
456 		} while (count);
457 	}
458 
459 	/*
460 	 * Wait for any in-progress I/O to complete before returning (why?)
461 	 */
462 	while (vp->v_track_write.bk_active > 0) {
463 		vp->v_track_write.bk_waitflag = 1;
464 		tsleep(&vp->v_track_write, 0, "vbtrunc", 0);
465 	}
466 
467 	crit_exit();
468 
469 	vnode_pager_setsize(vp, length);
470 
471 	return (0);
472 }
473 
474 /*
475  * The callback buffer is beyond the new file EOF and must be destroyed.
476  * Note that the compare function must conform to the RB_SCAN's requirements.
477  */
478 static
479 int
480 vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data)
481 {
482 	if (bp->b_lblkno >= *(daddr_t *)data)
483 		return(0);
484 	return(-1);
485 }
486 
487 static
488 int
489 vtruncbuf_bp_trunc(struct buf *bp, void *data)
490 {
491 	/*
492 	 * Do not try to use a buffer we cannot immediately lock, but sleep
493 	 * anyway to prevent a livelock.  The code will loop until all buffers
494 	 * can be acted upon.
495 	 */
496 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
497 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
498 			BUF_UNLOCK(bp);
499 	} else {
500 		bremfree(bp);
501 		bp->b_flags |= (B_INVAL | B_RELBUF);
502 		bp->b_flags &= ~B_ASYNC;
503 		brelse(bp);
504 	}
505 	return(1);
506 }
507 
508 /*
509  * Fsync all meta-data after truncating a file to be non-zero.  Only metadata
510  * blocks (with a negative lblkno) are scanned.
511  * Note that the compare function must conform to the RB_SCAN's requirements.
512  */
513 static int
514 vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data)
515 {
516 	if (bp->b_lblkno < 0)
517 		return(0);
518 	return(1);
519 }
520 
521 static int
522 vtruncbuf_bp_metasync(struct buf *bp, void *data)
523 {
524 	struct vnode *vp = data;
525 
526 	if (bp->b_flags & B_DELWRI) {
527 		/*
528 		 * Do not try to use a buffer we cannot immediately lock,
529 		 * but sleep anyway to prevent a livelock.  The code will
530 		 * loop until all buffers can be acted upon.
531 		 */
532 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
533 			if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
534 				BUF_UNLOCK(bp);
535 		} else {
536 			bremfree(bp);
537 			if (bp->b_vp == vp) {
538 				bp->b_flags |= B_ASYNC;
539 			} else {
540 				bp->b_flags &= ~B_ASYNC;
541 			}
542 			VOP_BWRITE(bp->b_vp, bp);
543 		}
544 		return(1);
545 	} else {
546 		return(0);
547 	}
548 }
549 
550 /*
551  * vfsync - implements a multipass fsync on a file which understands
552  * dependancies and meta-data.  The passed vnode must be locked.  The
553  * waitfor argument may be MNT_WAIT or MNT_NOWAIT, or MNT_LAZY.
554  *
555  * When fsyncing data asynchronously just do one consolidated pass starting
556  * with the most negative block number.  This may not get all the data due
557  * to dependancies.
558  *
559  * When fsyncing data synchronously do a data pass, then a metadata pass,
560  * then do additional data+metadata passes to try to get all the data out.
561  */
562 static int vfsync_wait_output(struct vnode *vp,
563 			    int (*waitoutput)(struct vnode *, struct thread *));
564 static int vfsync_data_only_cmp(struct buf *bp, void *data);
565 static int vfsync_meta_only_cmp(struct buf *bp, void *data);
566 static int vfsync_lazy_range_cmp(struct buf *bp, void *data);
567 static int vfsync_bp(struct buf *bp, void *data);
568 
569 struct vfsync_info {
570 	struct vnode *vp;
571 	int synchronous;
572 	int syncdeps;
573 	int lazycount;
574 	int lazylimit;
575 	daddr_t lbn;
576 	int (*checkdef)(struct buf *);
577 };
578 
579 int
580 vfsync(struct vnode *vp, int waitfor, int passes, daddr_t lbn,
581 	int (*checkdef)(struct buf *),
582 	int (*waitoutput)(struct vnode *, struct thread *))
583 {
584 	struct vfsync_info info;
585 	int error;
586 
587 	bzero(&info, sizeof(info));
588 	info.vp = vp;
589 	info.lbn = lbn;
590 	if ((info.checkdef = checkdef) == NULL)
591 		info.syncdeps = 1;
592 
593 	crit_enter();
594 
595 	switch(waitfor) {
596 	case MNT_LAZY:
597 		/*
598 		 * Lazy (filesystem syncer typ) Asynchronous plus limit the
599 		 * number of data (not meta) pages we try to flush to 1MB.
600 		 * A non-zero return means that lazy limit was reached.
601 		 */
602 		info.lazylimit = 1024 * 1024;
603 		info.syncdeps = 1;
604 		error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
605 				vfsync_lazy_range_cmp, vfsync_bp, &info);
606 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
607 				vfsync_meta_only_cmp, vfsync_bp, &info);
608 		if (error == 0)
609 			vp->v_lazyw = 0;
610 		else if (!RB_EMPTY(&vp->v_rbdirty_tree))
611 			vn_syncer_add_to_worklist(vp, 1);
612 		error = 0;
613 		break;
614 	case MNT_NOWAIT:
615 		/*
616 		 * Asynchronous.  Do a data-only pass and a meta-only pass.
617 		 */
618 		info.syncdeps = 1;
619 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
620 			vfsync_bp, &info);
621 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_meta_only_cmp,
622 			vfsync_bp, &info);
623 		error = 0;
624 		break;
625 	default:
626 		/*
627 		 * Synchronous.  Do a data-only pass, then a meta-data+data
628 		 * pass, then additional integrated passes to try to get
629 		 * all the dependancies flushed.
630 		 */
631 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
632 			vfsync_bp, &info);
633 		error = vfsync_wait_output(vp, waitoutput);
634 		if (error == 0) {
635 			RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
636 				vfsync_bp, &info);
637 			error = vfsync_wait_output(vp, waitoutput);
638 		}
639 		while (error == 0 && passes > 0 &&
640 		    !RB_EMPTY(&vp->v_rbdirty_tree)) {
641 			if (--passes == 0) {
642 				info.synchronous = 1;
643 				info.syncdeps = 1;
644 			}
645 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
646 				vfsync_bp, &info);
647 			if (error < 0)
648 				error = -error;
649 			info.syncdeps = 1;
650 			if (error == 0)
651 				error = vfsync_wait_output(vp, waitoutput);
652 		}
653 		break;
654 	}
655 	crit_exit();
656 	return(error);
657 }
658 
659 static int
660 vfsync_wait_output(struct vnode *vp, int (*waitoutput)(struct vnode *, struct thread *))
661 {
662 	int error = 0;
663 
664 	while (vp->v_track_write.bk_active) {
665 		vp->v_track_write.bk_waitflag = 1;
666 		tsleep(&vp->v_track_write, 0, "fsfsn", 0);
667 	}
668 	if (waitoutput)
669 		error = waitoutput(vp, curthread);
670 	return(error);
671 }
672 
673 static int
674 vfsync_data_only_cmp(struct buf *bp, void *data)
675 {
676 	if (bp->b_lblkno < 0)
677 		return(-1);
678 	return(0);
679 }
680 
681 static int
682 vfsync_meta_only_cmp(struct buf *bp, void *data)
683 {
684 	if (bp->b_lblkno < 0)
685 		return(0);
686 	return(1);
687 }
688 
689 static int
690 vfsync_lazy_range_cmp(struct buf *bp, void *data)
691 {
692 	struct vfsync_info *info = data;
693 	if (bp->b_lblkno < info->vp->v_lazyw)
694 		return(-1);
695 	return(0);
696 }
697 
698 static int
699 vfsync_bp(struct buf *bp, void *data)
700 {
701 	struct vfsync_info *info = data;
702 	struct vnode *vp = info->vp;
703 	int error;
704 
705 	/*
706 	 * if syncdeps is not set we do not try to write buffers which have
707 	 * dependancies.
708 	 */
709 	if (!info->synchronous && info->syncdeps == 0 && info->checkdef(bp))
710 		return(0);
711 
712 	/*
713 	 * Ignore buffers that we cannot immediately lock.  XXX
714 	 */
715 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT))
716 		return(0);
717 	if ((bp->b_flags & B_DELWRI) == 0)
718 		panic("vfsync_bp: buffer not dirty");
719 	if (vp != bp->b_vp)
720 		panic("vfsync_bp: buffer vp mismatch");
721 
722 	/*
723 	 * B_NEEDCOMMIT (primarily used by NFS) is a state where the buffer
724 	 * has been written but an additional handshake with the device
725 	 * is required before we can dispose of the buffer.  We have no idea
726 	 * how to do this so we have to skip these buffers.
727 	 */
728 	if (bp->b_flags & B_NEEDCOMMIT) {
729 		BUF_UNLOCK(bp);
730 		return(0);
731 	}
732 
733 	/*
734 	 * (LEGACY FROM UFS, REMOVE WHEN POSSIBLE) - invalidate any dirty
735 	 * buffers beyond the file EOF.
736 	 */
737 	if (info->lbn != (daddr_t)-1 && vp->v_type == VREG &&
738 	    bp->b_lblkno >= info->lbn) {
739 		bremfree(bp);
740 		bp->b_flags |= B_INVAL | B_NOCACHE;
741 		crit_exit();
742 		brelse(bp);
743 		crit_enter();
744 	}
745 
746 	if (info->synchronous) {
747 		/*
748 		 * Synchronous flushing.  An error may be returned.
749 		 */
750 		bremfree(bp);
751 		crit_exit();
752 		error = bwrite(bp);
753 		crit_enter();
754 	} else {
755 		/*
756 		 * Asynchronous flushing.  A negative return value simply
757 		 * stops the scan and is not considered an error.  We use
758 		 * this to support limited MNT_LAZY flushes.
759 		 */
760 		vp->v_lazyw = bp->b_lblkno;
761 		if ((vp->v_flag & VOBJBUF) && (bp->b_flags & B_CLUSTEROK)) {
762 			BUF_UNLOCK(bp);
763 			info->lazycount += vfs_bio_awrite(bp);
764 		} else {
765 			info->lazycount += bp->b_bufsize;
766 			bremfree(bp);
767 			crit_exit();
768 			bawrite(bp);
769 			crit_enter();
770 		}
771 		if (info->lazylimit && info->lazycount >= info->lazylimit)
772 			error = 1;
773 		else
774 			error = 0;
775 	}
776 	return(-error);
777 }
778 
779 /*
780  * Associate a buffer with a vnode.
781  */
782 void
783 bgetvp(struct vnode *vp, struct buf *bp)
784 {
785 	KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));
786 
787 	vhold(vp);
788 	bp->b_vp = vp;
789 	/*
790 	 * Insert onto list for new vnode.
791 	 */
792 	crit_enter();
793 	bp->b_xflags |= BX_VNCLEAN;
794 	bp->b_xflags &= ~BX_VNDIRTY;
795 	if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp))
796 		panic("reassignbuf: dup lblk vp %p bp %p", vp, bp);
797 	crit_exit();
798 }
799 
800 /*
801  * Disassociate a buffer from a vnode.
802  */
803 void
804 brelvp(struct buf *bp)
805 {
806 	struct vnode *vp;
807 
808 	KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
809 
810 	/*
811 	 * Delete from old vnode list, if on one.
812 	 */
813 	vp = bp->b_vp;
814 	crit_enter();
815 	if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) {
816 		if (bp->b_xflags & BX_VNDIRTY)
817 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
818 		else
819 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
820 		bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
821 	}
822 	if ((vp->v_flag & VONWORKLST) && RB_EMPTY(&vp->v_rbdirty_tree)) {
823 		vp->v_flag &= ~VONWORKLST;
824 		LIST_REMOVE(vp, v_synclist);
825 	}
826 	crit_exit();
827 	bp->b_vp = NULL;
828 	vdrop(vp);
829 }
830 
831 /*
832  * Associate a p-buffer with a vnode.
833  *
834  * Also sets B_PAGING flag to indicate that vnode is not fully associated
835  * with the buffer.  i.e. the bp has not been linked into the vnode or
836  * ref-counted.
837  */
838 void
839 pbgetvp(struct vnode *vp, struct buf *bp)
840 {
841 	KASSERT(bp->b_vp == NULL, ("pbgetvp: not free"));
842 
843 	bp->b_vp = vp;
844 	bp->b_flags |= B_PAGING;
845 }
846 
847 /*
848  * Disassociate a p-buffer from a vnode.
849  */
850 void
851 pbrelvp(struct buf *bp)
852 {
853 	KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL"));
854 
855 	bp->b_vp = NULL;
856 	bp->b_flags &= ~B_PAGING;
857 }
858 
859 void
860 pbreassignbuf(struct buf *bp, struct vnode *newvp)
861 {
862 	if ((bp->b_flags & B_PAGING) == 0) {
863 		panic(
864 		    "pbreassignbuf() on non phys bp %p",
865 		    bp
866 		);
867 	}
868 	bp->b_vp = newvp;
869 }
870 
871 /*
872  * Reassign a buffer from one vnode to another.
873  * Used to assign file specific control information
874  * (indirect blocks) to the vnode to which they belong.
875  */
876 void
877 reassignbuf(struct buf *bp, struct vnode *newvp)
878 {
879 	int delay;
880 
881 	if (newvp == NULL) {
882 		printf("reassignbuf: NULL");
883 		return;
884 	}
885 	++reassignbufcalls;
886 
887 	/*
888 	 * B_PAGING flagged buffers cannot be reassigned because their vp
889 	 * is not fully linked in.
890 	 */
891 	if (bp->b_flags & B_PAGING)
892 		panic("cannot reassign paging buffer");
893 
894 	crit_enter();
895 	/*
896 	 * Delete from old vnode list, if on one.
897 	 */
898 	if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) {
899 		if (bp->b_xflags & BX_VNDIRTY)
900 			buf_rb_tree_RB_REMOVE(&bp->b_vp->v_rbdirty_tree, bp);
901 		else
902 			buf_rb_tree_RB_REMOVE(&bp->b_vp->v_rbclean_tree, bp);
903 		bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
904 		if (bp->b_vp != newvp) {
905 			vdrop(bp->b_vp);
906 			bp->b_vp = NULL;	/* for clarification */
907 		}
908 	}
909 	/*
910 	 * If dirty, put on list of dirty buffers; otherwise insert onto list
911 	 * of clean buffers.
912 	 */
913 	if (bp->b_flags & B_DELWRI) {
914 		if ((newvp->v_flag & VONWORKLST) == 0) {
915 			switch (newvp->v_type) {
916 			case VDIR:
917 				delay = dirdelay;
918 				break;
919 			case VCHR:
920 			case VBLK:
921 				if (newvp->v_rdev &&
922 				    newvp->v_rdev->si_mountpoint != NULL) {
923 					delay = metadelay;
924 					break;
925 				}
926 				/* fall through */
927 			default:
928 				delay = filedelay;
929 			}
930 			vn_syncer_add_to_worklist(newvp, delay);
931 		}
932 		bp->b_xflags |= BX_VNDIRTY;
933 		if (buf_rb_tree_RB_INSERT(&newvp->v_rbdirty_tree, bp))
934 			panic("reassignbuf: dup lblk vp %p bp %p", newvp, bp);
935 	} else {
936 		bp->b_xflags |= BX_VNCLEAN;
937 		if (buf_rb_tree_RB_INSERT(&newvp->v_rbclean_tree, bp))
938 			panic("reassignbuf: dup lblk vp %p bp %p", newvp, bp);
939 		if ((newvp->v_flag & VONWORKLST) &&
940 		    RB_EMPTY(&newvp->v_rbdirty_tree)) {
941 			newvp->v_flag &= ~VONWORKLST;
942 			LIST_REMOVE(newvp, v_synclist);
943 		}
944 	}
945 	if (bp->b_vp != newvp) {
946 		bp->b_vp = newvp;
947 		vhold(bp->b_vp);
948 	}
949 	crit_exit();
950 }
951 
952 /*
953  * Create a vnode for a block device.
954  * Used for mounting the root file system.
955  */
956 int
957 bdevvp(dev_t dev, struct vnode **vpp)
958 {
959 	struct vnode *vp;
960 	struct vnode *nvp;
961 	int error;
962 
963 	if (dev == NODEV) {
964 		*vpp = NULLVP;
965 		return (ENXIO);
966 	}
967 	error = getspecialvnode(VT_NON, NULL, &spec_vnode_vops, &nvp, 0, 0);
968 	if (error) {
969 		*vpp = NULLVP;
970 		return (error);
971 	}
972 	vp = nvp;
973 	vp->v_type = VCHR;
974 	vp->v_udev = dev->si_udev;
975 	vx_unlock(vp);
976 	*vpp = vp;
977 	return (0);
978 }
979 
980 int
981 v_associate_rdev(struct vnode *vp, dev_t dev)
982 {
983 	lwkt_tokref ilock;
984 
985 	if (dev == NULL || dev == NODEV)
986 		return(ENXIO);
987 	if (dev_is_good(dev) == 0)
988 		return(ENXIO);
989 	KKASSERT(vp->v_rdev == NULL);
990 	if (dev_ref_debug)
991 		printf("Z1");
992 	vp->v_rdev = reference_dev(dev);
993 	lwkt_gettoken(&ilock, &spechash_token);
994 	SLIST_INSERT_HEAD(&dev->si_hlist, vp, v_specnext);
995 	lwkt_reltoken(&ilock);
996 	return(0);
997 }
998 
999 void
1000 v_release_rdev(struct vnode *vp)
1001 {
1002 	lwkt_tokref ilock;
1003 	dev_t dev;
1004 
1005 	if ((dev = vp->v_rdev) != NULL) {
1006 		lwkt_gettoken(&ilock, &spechash_token);
1007 		SLIST_REMOVE(&dev->si_hlist, vp, vnode, v_specnext);
1008 		if (dev_ref_debug && vp->v_opencount != 0) {
1009 			printf("releasing rdev with non-0 "
1010 				"v_opencount(%d) (revoked?)\n",
1011 				vp->v_opencount);
1012 		}
1013 		vp->v_rdev = NULL;
1014 		vp->v_opencount = 0;
1015 		release_dev(dev);
1016 		lwkt_reltoken(&ilock);
1017 	}
1018 }
1019 
1020 /*
1021  * Add a vnode to the alias list hung off the dev_t.  We only associate
1022  * the device number with the vnode.  The actual device is not associated
1023  * until the vnode is opened (usually in spec_open()), and will be
1024  * disassociated on last close.
1025  */
1026 void
1027 addaliasu(struct vnode *nvp, udev_t nvp_udev)
1028 {
1029 	if (nvp->v_type != VBLK && nvp->v_type != VCHR)
1030 		panic("addaliasu on non-special vnode");
1031 	nvp->v_udev = nvp_udev;
1032 }
1033 
1034 /*
1035  * Disassociate a vnode from its underlying filesystem.
1036  *
1037  * The vnode must be VX locked and refd
1038  *
1039  * If there are v_usecount references to the vnode other then ours we have
1040  * to VOP_CLOSE the vnode before we can deactivate and reclaim it.
1041  */
1042 void
1043 vclean(struct vnode *vp, int flags, struct thread *td)
1044 {
1045 	int active;
1046 	int retflags = 0;
1047 
1048 	/*
1049 	 * If the vnode has already been reclaimed we have nothing to do.
1050 	 */
1051 	if (vp->v_flag & VRECLAIMED)
1052 		return;
1053 	vp->v_flag |= VRECLAIMED;
1054 
1055 	/*
1056 	 * Scrap the vfs cache
1057 	 */
1058 	while (cache_inval_vp(vp, 0, &retflags) != 0) {
1059 		printf("Warning: vnode %p clean/cache_resolution race detected\n", vp);
1060 		tsleep(vp, 0, "vclninv", 2);
1061 	}
1062 
1063 	/*
1064 	 * Check to see if the vnode is in use. If so we have to reference it
1065 	 * before we clean it out so that its count cannot fall to zero and
1066 	 * generate a race against ourselves to recycle it.
1067 	 */
1068 	active = (vp->v_usecount > 1);
1069 
1070 	/*
1071 	 * Clean out any buffers associated with the vnode and destroy its
1072 	 * object, if it has one.
1073 	 */
1074 	vinvalbuf(vp, V_SAVE, td, 0, 0);
1075 	VOP_DESTROYVOBJECT(vp);
1076 
1077 	/*
1078 	 * If purging an active vnode, it must be closed and
1079 	 * deactivated before being reclaimed.   XXX
1080 	 *
1081 	 * Note that neither of these routines unlocks the vnode.
1082 	 */
1083 	if (active) {
1084 		if (flags & DOCLOSE)
1085 			VOP_CLOSE(vp, FNONBLOCK, td);
1086 	}
1087 
1088 	/*
1089 	 * If the vnode has not be deactivated, deactivated it.
1090 	 */
1091 	if ((vp->v_flag & VINACTIVE) == 0) {
1092 		vp->v_flag |= VINACTIVE;
1093 		VOP_INACTIVE(vp, td);
1094 	}
1095 
1096 	/*
1097 	 * Reclaim the vnode.
1098 	 */
1099 	if (VOP_RECLAIM(vp, retflags, td))
1100 		panic("vclean: cannot reclaim");
1101 
1102 	/*
1103 	 * Done with purge, notify sleepers of the grim news.
1104 	 */
1105 	vp->v_ops = &dead_vnode_vops;
1106 	vn_pollgone(vp);
1107 	vp->v_tag = VT_NON;
1108 }
1109 
1110 /*
1111  * Eliminate all activity associated with the requested vnode
1112  * and with all vnodes aliased to the requested vnode.
1113  *
1114  * The vnode must be referenced and vx_lock()'d
1115  *
1116  * revoke { struct vnode *a_vp, int a_flags }
1117  */
1118 int
1119 vop_stdrevoke(struct vop_revoke_args *ap)
1120 {
1121 	struct vnode *vp, *vq;
1122 	lwkt_tokref ilock;
1123 	dev_t dev;
1124 
1125 	KASSERT((ap->a_flags & REVOKEALL) != 0, ("vop_revoke"));
1126 
1127 	vp = ap->a_vp;
1128 
1129 	/*
1130 	 * If the vnode is already dead don't try to revoke it
1131 	 */
1132 	if (vp->v_flag & VRECLAIMED)
1133 		return (0);
1134 
1135 	/*
1136 	 * If the vnode has a device association, scrap all vnodes associated
1137 	 * with the device.  Don't let the device disappear on us while we
1138 	 * are scrapping the vnodes.
1139 	 *
1140 	 * The passed vp will probably show up in the list, do not VX lock
1141 	 * it twice!
1142 	 */
1143 	if (vp->v_type != VCHR && vp->v_type != VBLK)
1144 		return(0);
1145 	if ((dev = vp->v_rdev) == NULL) {
1146 		if ((dev = udev2dev(vp->v_udev, vp->v_type == VBLK)) == NODEV)
1147 			return(0);
1148 	}
1149 	reference_dev(dev);
1150 	lwkt_gettoken(&ilock, &spechash_token);
1151 	while ((vq = SLIST_FIRST(&dev->si_hlist)) != NULL) {
1152 		if (vp == vq || vx_get(vq) == 0) {
1153 			if (vq == SLIST_FIRST(&dev->si_hlist))
1154 				vgone(vq);
1155 			if (vp != vq)
1156 				vx_put(vq);
1157 		}
1158 	}
1159 	lwkt_reltoken(&ilock);
1160 	release_dev(dev);
1161 	return (0);
1162 }
1163 
1164 /*
1165  * Recycle an unused vnode to the front of the free list.
1166  *
1167  * Returns 1 if we were successfully able to recycle the vnode,
1168  * 0 otherwise.
1169  */
1170 int
1171 vrecycle(struct vnode *vp, struct thread *td)
1172 {
1173 	if (vp->v_usecount == 1) {
1174 		vgone(vp);
1175 		return (1);
1176 	}
1177 	return (0);
1178 }
1179 
1180 /*
1181  * Eliminate all activity associated with a vnode in preparation for reuse.
1182  *
1183  * The vnode must be VX locked and refd and will remain VX locked and refd
1184  * on return.  This routine may be called with the vnode in any state, as
1185  * long as it is VX locked.  The vnode will be cleaned out and marked
1186  * VRECLAIMED but will not actually be reused until all existing refs and
1187  * holds go away.
1188  *
1189  * NOTE: This routine may be called on a vnode which has not yet been
1190  * already been deactivated (VOP_INACTIVE), or on a vnode which has
1191  * already been reclaimed.
1192  *
1193  * This routine is not responsible for placing us back on the freelist.
1194  * Instead, it happens automatically when the caller releases the VX lock
1195  * (assuming there aren't any other references).
1196  */
1197 void
1198 vgone(struct vnode *vp)
1199 {
1200 	/*
1201 	 * assert that the VX lock is held.  This is an absolute requirement
1202 	 * now for vgone() to be called.
1203 	 */
1204 	KKASSERT(vp->v_lock.lk_exclusivecount == 1);
1205 
1206 	/*
1207 	 * Clean out the filesystem specific data and set the VRECLAIMED
1208 	 * bit.  Also deactivate the vnode if necessary.
1209 	 */
1210 	vclean(vp, DOCLOSE, curthread);
1211 
1212 	/*
1213 	 * Delete from old mount point vnode list, if on one.
1214 	 */
1215 	if (vp->v_mount != NULL)
1216 		insmntque(vp, NULL);
1217 
1218 	/*
1219 	 * If special device, remove it from special device alias list
1220 	 * if it is on one.  This should normally only occur if a vnode is
1221 	 * being revoked as the device should otherwise have been released
1222 	 * naturally.
1223 	 */
1224 	if ((vp->v_type == VBLK || vp->v_type == VCHR) && vp->v_rdev != NULL) {
1225 		v_release_rdev(vp);
1226 	}
1227 
1228 	/*
1229 	 * Set us to VBAD
1230 	 */
1231 	vp->v_type = VBAD;
1232 }
1233 
1234 /*
1235  * Lookup a vnode by device number.
1236  */
1237 int
1238 vfinddev(dev_t dev, enum vtype type, struct vnode **vpp)
1239 {
1240 	lwkt_tokref ilock;
1241 	struct vnode *vp;
1242 
1243 	lwkt_gettoken(&ilock, &spechash_token);
1244 	SLIST_FOREACH(vp, &dev->si_hlist, v_specnext) {
1245 		if (type == vp->v_type) {
1246 			*vpp = vp;
1247 			lwkt_reltoken(&ilock);
1248 			return (1);
1249 		}
1250 	}
1251 	lwkt_reltoken(&ilock);
1252 	return (0);
1253 }
1254 
1255 /*
1256  * Calculate the total number of references to a special device.  This
1257  * routine may only be called for VBLK and VCHR vnodes since v_rdev is
1258  * an overloaded field.  Since udev2dev can now return NODEV, we have
1259  * to check for a NULL v_rdev.
1260  */
1261 int
1262 count_dev(dev_t dev)
1263 {
1264 	lwkt_tokref ilock;
1265 	struct vnode *vp;
1266 	int count = 0;
1267 
1268 	if (SLIST_FIRST(&dev->si_hlist)) {
1269 		lwkt_gettoken(&ilock, &spechash_token);
1270 		SLIST_FOREACH(vp, &dev->si_hlist, v_specnext) {
1271 			count += vp->v_usecount;
1272 		}
1273 		lwkt_reltoken(&ilock);
1274 	}
1275 	return(count);
1276 }
1277 
1278 int
1279 count_udev(udev_t udev)
1280 {
1281 	dev_t dev;
1282 
1283 	if ((dev = udev2dev(udev, 0)) == NODEV)
1284 		return(0);
1285 	return(count_dev(dev));
1286 }
1287 
1288 int
1289 vcount(struct vnode *vp)
1290 {
1291 	if (vp->v_rdev == NULL)
1292 		return(0);
1293 	return(count_dev(vp->v_rdev));
1294 }
1295 
1296 /*
1297  * Print out a description of a vnode.
1298  */
1299 static char *typename[] =
1300 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
1301 
1302 void
1303 vprint(char *label, struct vnode *vp)
1304 {
1305 	char buf[96];
1306 
1307 	if (label != NULL)
1308 		printf("%s: %p: ", label, (void *)vp);
1309 	else
1310 		printf("%p: ", (void *)vp);
1311 	printf("type %s, usecount %d, writecount %d, refcount %d,",
1312 	    typename[vp->v_type], vp->v_usecount, vp->v_writecount,
1313 	    vp->v_holdcnt);
1314 	buf[0] = '\0';
1315 	if (vp->v_flag & VROOT)
1316 		strcat(buf, "|VROOT");
1317 	if (vp->v_flag & VTEXT)
1318 		strcat(buf, "|VTEXT");
1319 	if (vp->v_flag & VSYSTEM)
1320 		strcat(buf, "|VSYSTEM");
1321 	if (vp->v_flag & VFREE)
1322 		strcat(buf, "|VFREE");
1323 	if (vp->v_flag & VOBJBUF)
1324 		strcat(buf, "|VOBJBUF");
1325 	if (buf[0] != '\0')
1326 		printf(" flags (%s)", &buf[1]);
1327 	if (vp->v_data == NULL) {
1328 		printf("\n");
1329 	} else {
1330 		printf("\n\t");
1331 		VOP_PRINT(vp);
1332 	}
1333 }
1334 
1335 #ifdef DDB
1336 #include <ddb/ddb.h>
1337 
1338 static int db_show_locked_vnodes(struct mount *mp, void *data);
1339 
1340 /*
1341  * List all of the locked vnodes in the system.
1342  * Called when debugging the kernel.
1343  */
1344 DB_SHOW_COMMAND(lockedvnodes, lockedvnodes)
1345 {
1346 	printf("Locked vnodes\n");
1347 	mountlist_scan(db_show_locked_vnodes, NULL,
1348 			MNTSCAN_FORWARD|MNTSCAN_NOBUSY);
1349 }
1350 
1351 static int
1352 db_show_locked_vnodes(struct mount *mp, void *data __unused)
1353 {
1354 	struct vnode *vp;
1355 
1356 	TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
1357 		if (VOP_ISLOCKED(vp, NULL))
1358 			vprint((char *)0, vp);
1359 	}
1360 	return(0);
1361 }
1362 #endif
1363 
1364 /*
1365  * Top level filesystem related information gathering.
1366  */
1367 static int	sysctl_ovfs_conf (SYSCTL_HANDLER_ARGS);
1368 
1369 static int
1370 vfs_sysctl(SYSCTL_HANDLER_ARGS)
1371 {
1372 	int *name = (int *)arg1 - 1;	/* XXX */
1373 	u_int namelen = arg2 + 1;	/* XXX */
1374 	struct vfsconf *vfsp;
1375 
1376 #if 1 || defined(COMPAT_PRELITE2)
1377 	/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
1378 	if (namelen == 1)
1379 		return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
1380 #endif
1381 
1382 #ifdef notyet
1383 	/* all sysctl names at this level are at least name and field */
1384 	if (namelen < 2)
1385 		return (ENOTDIR);		/* overloaded */
1386 	if (name[0] != VFS_GENERIC) {
1387 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
1388 			if (vfsp->vfc_typenum == name[0])
1389 				break;
1390 		if (vfsp == NULL)
1391 			return (EOPNOTSUPP);
1392 		return ((*vfsp->vfc_vfsops->vfs_sysctl)(&name[1], namelen - 1,
1393 		    oldp, oldlenp, newp, newlen, p));
1394 	}
1395 #endif
1396 	switch (name[1]) {
1397 	case VFS_MAXTYPENUM:
1398 		if (namelen != 2)
1399 			return (ENOTDIR);
1400 		return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
1401 	case VFS_CONF:
1402 		if (namelen != 3)
1403 			return (ENOTDIR);	/* overloaded */
1404 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
1405 			if (vfsp->vfc_typenum == name[2])
1406 				break;
1407 		if (vfsp == NULL)
1408 			return (EOPNOTSUPP);
1409 		return (SYSCTL_OUT(req, vfsp, sizeof *vfsp));
1410 	}
1411 	return (EOPNOTSUPP);
1412 }
1413 
1414 SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD, vfs_sysctl,
1415 	"Generic filesystem");
1416 
1417 #if 1 || defined(COMPAT_PRELITE2)
1418 
1419 static int
1420 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
1421 {
1422 	int error;
1423 	struct vfsconf *vfsp;
1424 	struct ovfsconf ovfs;
1425 
1426 	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
1427 		bzero(&ovfs, sizeof(ovfs));
1428 		ovfs.vfc_vfsops = vfsp->vfc_vfsops;	/* XXX used as flag */
1429 		strcpy(ovfs.vfc_name, vfsp->vfc_name);
1430 		ovfs.vfc_index = vfsp->vfc_typenum;
1431 		ovfs.vfc_refcount = vfsp->vfc_refcount;
1432 		ovfs.vfc_flags = vfsp->vfc_flags;
1433 		error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
1434 		if (error)
1435 			return error;
1436 	}
1437 	return 0;
1438 }
1439 
1440 #endif /* 1 || COMPAT_PRELITE2 */
1441 
1442 /*
1443  * Check to see if a filesystem is mounted on a block device.
1444  */
1445 int
1446 vfs_mountedon(struct vnode *vp)
1447 {
1448 	dev_t dev;
1449 
1450 	if ((dev = vp->v_rdev) == NULL)
1451 		dev = udev2dev(vp->v_udev, (vp->v_type == VBLK));
1452 	if (dev != NODEV && dev->si_mountpoint)
1453 		return (EBUSY);
1454 	return (0);
1455 }
1456 
1457 /*
1458  * Unmount all filesystems. The list is traversed in reverse order
1459  * of mounting to avoid dependencies.
1460  */
1461 
1462 static int vfs_umountall_callback(struct mount *mp, void *data);
1463 
1464 void
1465 vfs_unmountall(void)
1466 {
1467 	struct thread *td = curthread;
1468 	int count;
1469 
1470 	if (td->td_proc == NULL)
1471 		td = initproc->p_thread;	/* XXX XXX use proc0 instead? */
1472 
1473 	do {
1474 		count = mountlist_scan(vfs_umountall_callback,
1475 					&td, MNTSCAN_REVERSE|MNTSCAN_NOBUSY);
1476 	} while (count);
1477 }
1478 
1479 static
1480 int
1481 vfs_umountall_callback(struct mount *mp, void *data)
1482 {
1483 	struct thread *td = *(struct thread **)data;
1484 	int error;
1485 
1486 	error = dounmount(mp, MNT_FORCE, td);
1487 	if (error) {
1488 		mountlist_remove(mp);
1489 		printf("unmount of filesystem mounted from %s failed (",
1490 			mp->mnt_stat.f_mntfromname);
1491 		if (error == EBUSY)
1492 			printf("BUSY)\n");
1493 		else
1494 			printf("%d)\n", error);
1495 	}
1496 	return(1);
1497 }
1498 
1499 /*
1500  * Build hash lists of net addresses and hang them off the mount point.
1501  * Called by ufs_mount() to set up the lists of export addresses.
1502  */
1503 static int
1504 vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
1505 		struct export_args *argp)
1506 {
1507 	struct netcred *np;
1508 	struct radix_node_head *rnh;
1509 	int i;
1510 	struct radix_node *rn;
1511 	struct sockaddr *saddr, *smask = 0;
1512 	struct domain *dom;
1513 	int error;
1514 
1515 	if (argp->ex_addrlen == 0) {
1516 		if (mp->mnt_flag & MNT_DEFEXPORTED)
1517 			return (EPERM);
1518 		np = &nep->ne_defexported;
1519 		np->netc_exflags = argp->ex_flags;
1520 		np->netc_anon = argp->ex_anon;
1521 		np->netc_anon.cr_ref = 1;
1522 		mp->mnt_flag |= MNT_DEFEXPORTED;
1523 		return (0);
1524 	}
1525 
1526 	if (argp->ex_addrlen < 0 || argp->ex_addrlen > MLEN)
1527 		return (EINVAL);
1528 	if (argp->ex_masklen < 0 || argp->ex_masklen > MLEN)
1529 		return (EINVAL);
1530 
1531 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
1532 	np = (struct netcred *) malloc(i, M_NETADDR, M_WAITOK);
1533 	bzero((caddr_t) np, i);
1534 	saddr = (struct sockaddr *) (np + 1);
1535 	if ((error = copyin(argp->ex_addr, (caddr_t) saddr, argp->ex_addrlen)))
1536 		goto out;
1537 	if (saddr->sa_len > argp->ex_addrlen)
1538 		saddr->sa_len = argp->ex_addrlen;
1539 	if (argp->ex_masklen) {
1540 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
1541 		error = copyin(argp->ex_mask, (caddr_t)smask, argp->ex_masklen);
1542 		if (error)
1543 			goto out;
1544 		if (smask->sa_len > argp->ex_masklen)
1545 			smask->sa_len = argp->ex_masklen;
1546 	}
1547 	i = saddr->sa_family;
1548 	if ((rnh = nep->ne_rtable[i]) == 0) {
1549 		/*
1550 		 * Seems silly to initialize every AF when most are not used,
1551 		 * do so on demand here
1552 		 */
1553 		SLIST_FOREACH(dom, &domains, dom_next)
1554 			if (dom->dom_family == i && dom->dom_rtattach) {
1555 				dom->dom_rtattach((void **) &nep->ne_rtable[i],
1556 				    dom->dom_rtoffset);
1557 				break;
1558 			}
1559 		if ((rnh = nep->ne_rtable[i]) == 0) {
1560 			error = ENOBUFS;
1561 			goto out;
1562 		}
1563 	}
1564 	rn = (*rnh->rnh_addaddr) ((char *) saddr, (char *) smask, rnh,
1565 	    np->netc_rnodes);
1566 	if (rn == 0 || np != (struct netcred *) rn) {	/* already exists */
1567 		error = EPERM;
1568 		goto out;
1569 	}
1570 	np->netc_exflags = argp->ex_flags;
1571 	np->netc_anon = argp->ex_anon;
1572 	np->netc_anon.cr_ref = 1;
1573 	return (0);
1574 out:
1575 	free(np, M_NETADDR);
1576 	return (error);
1577 }
1578 
1579 /* ARGSUSED */
1580 static int
1581 vfs_free_netcred(struct radix_node *rn, void *w)
1582 {
1583 	struct radix_node_head *rnh = (struct radix_node_head *) w;
1584 
1585 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
1586 	free((caddr_t) rn, M_NETADDR);
1587 	return (0);
1588 }
1589 
1590 /*
1591  * Free the net address hash lists that are hanging off the mount points.
1592  */
1593 static void
1594 vfs_free_addrlist(struct netexport *nep)
1595 {
1596 	int i;
1597 	struct radix_node_head *rnh;
1598 
1599 	for (i = 0; i <= AF_MAX; i++)
1600 		if ((rnh = nep->ne_rtable[i])) {
1601 			(*rnh->rnh_walktree) (rnh, vfs_free_netcred,
1602 			    (caddr_t) rnh);
1603 			free((caddr_t) rnh, M_RTABLE);
1604 			nep->ne_rtable[i] = 0;
1605 		}
1606 }
1607 
1608 int
1609 vfs_export(struct mount *mp, struct netexport *nep, struct export_args *argp)
1610 {
1611 	int error;
1612 
1613 	if (argp->ex_flags & MNT_DELEXPORT) {
1614 		if (mp->mnt_flag & MNT_EXPUBLIC) {
1615 			vfs_setpublicfs(NULL, NULL, NULL);
1616 			mp->mnt_flag &= ~MNT_EXPUBLIC;
1617 		}
1618 		vfs_free_addrlist(nep);
1619 		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
1620 	}
1621 	if (argp->ex_flags & MNT_EXPORTED) {
1622 		if (argp->ex_flags & MNT_EXPUBLIC) {
1623 			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
1624 				return (error);
1625 			mp->mnt_flag |= MNT_EXPUBLIC;
1626 		}
1627 		if ((error = vfs_hang_addrlist(mp, nep, argp)))
1628 			return (error);
1629 		mp->mnt_flag |= MNT_EXPORTED;
1630 	}
1631 	return (0);
1632 }
1633 
1634 
1635 /*
1636  * Set the publicly exported filesystem (WebNFS). Currently, only
1637  * one public filesystem is possible in the spec (RFC 2054 and 2055)
1638  */
1639 int
1640 vfs_setpublicfs(struct mount *mp, struct netexport *nep,
1641 		struct export_args *argp)
1642 {
1643 	int error;
1644 	struct vnode *rvp;
1645 	char *cp;
1646 
1647 	/*
1648 	 * mp == NULL -> invalidate the current info, the FS is
1649 	 * no longer exported. May be called from either vfs_export
1650 	 * or unmount, so check if it hasn't already been done.
1651 	 */
1652 	if (mp == NULL) {
1653 		if (nfs_pub.np_valid) {
1654 			nfs_pub.np_valid = 0;
1655 			if (nfs_pub.np_index != NULL) {
1656 				FREE(nfs_pub.np_index, M_TEMP);
1657 				nfs_pub.np_index = NULL;
1658 			}
1659 		}
1660 		return (0);
1661 	}
1662 
1663 	/*
1664 	 * Only one allowed at a time.
1665 	 */
1666 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
1667 		return (EBUSY);
1668 
1669 	/*
1670 	 * Get real filehandle for root of exported FS.
1671 	 */
1672 	bzero((caddr_t)&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
1673 	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
1674 
1675 	if ((error = VFS_ROOT(mp, &rvp)))
1676 		return (error);
1677 
1678 	if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
1679 		return (error);
1680 
1681 	vput(rvp);
1682 
1683 	/*
1684 	 * If an indexfile was specified, pull it in.
1685 	 */
1686 	if (argp->ex_indexfile != NULL) {
1687 		int namelen;
1688 
1689 		error = vn_get_namelen(rvp, &namelen);
1690 		if (error)
1691 			return (error);
1692 		MALLOC(nfs_pub.np_index, char *, namelen, M_TEMP,
1693 		    M_WAITOK);
1694 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
1695 		    namelen, (size_t *)0);
1696 		if (!error) {
1697 			/*
1698 			 * Check for illegal filenames.
1699 			 */
1700 			for (cp = nfs_pub.np_index; *cp; cp++) {
1701 				if (*cp == '/') {
1702 					error = EINVAL;
1703 					break;
1704 				}
1705 			}
1706 		}
1707 		if (error) {
1708 			FREE(nfs_pub.np_index, M_TEMP);
1709 			return (error);
1710 		}
1711 	}
1712 
1713 	nfs_pub.np_mount = mp;
1714 	nfs_pub.np_valid = 1;
1715 	return (0);
1716 }
1717 
1718 struct netcred *
1719 vfs_export_lookup(struct mount *mp, struct netexport *nep,
1720 		struct sockaddr *nam)
1721 {
1722 	struct netcred *np;
1723 	struct radix_node_head *rnh;
1724 	struct sockaddr *saddr;
1725 
1726 	np = NULL;
1727 	if (mp->mnt_flag & MNT_EXPORTED) {
1728 		/*
1729 		 * Lookup in the export list first.
1730 		 */
1731 		if (nam != NULL) {
1732 			saddr = nam;
1733 			rnh = nep->ne_rtable[saddr->sa_family];
1734 			if (rnh != NULL) {
1735 				np = (struct netcred *)
1736 					(*rnh->rnh_matchaddr)((char *)saddr,
1737 							      rnh);
1738 				if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
1739 					np = NULL;
1740 			}
1741 		}
1742 		/*
1743 		 * If no address match, use the default if it exists.
1744 		 */
1745 		if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
1746 			np = &nep->ne_defexported;
1747 	}
1748 	return (np);
1749 }
1750 
1751 /*
1752  * perform msync on all vnodes under a mount point.  The mount point must
1753  * be locked.  This code is also responsible for lazy-freeing unreferenced
1754  * vnodes whos VM objects no longer contain pages.
1755  *
1756  * NOTE: MNT_WAIT still skips vnodes in the VXLOCK state.
1757  *
1758  * NOTE: XXX VOP_PUTPAGES and friends requires that the vnode be locked,
1759  * but vnode_pager_putpages() doesn't lock the vnode.  We have to do it
1760  * way up in this high level function.
1761  */
1762 static int vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data);
1763 static int vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data);
1764 
1765 void
1766 vfs_msync(struct mount *mp, int flags)
1767 {
1768 	int vmsc_flags;
1769 
1770 	vmsc_flags = VMSC_GETVP;
1771 	if (flags != MNT_WAIT)
1772 		vmsc_flags |= VMSC_NOWAIT;
1773 	vmntvnodescan(mp, vmsc_flags, vfs_msync_scan1, vfs_msync_scan2,
1774 			(void *)flags);
1775 }
1776 
1777 /*
1778  * scan1 is a fast pre-check.  There could be hundreds of thousands of
1779  * vnodes, we cannot afford to do anything heavy weight until we have a
1780  * fairly good indication that there is work to do.
1781  */
1782 static
1783 int
1784 vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data)
1785 {
1786 	int flags = (int)data;
1787 
1788 	if ((vp->v_flag & VRECLAIMED) == 0) {
1789 		if (vshouldfree(vp, 0))
1790 			return(0);	/* call scan2 */
1791 		if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
1792 		    (vp->v_flag & VOBJDIRTY) &&
1793 		    (flags == MNT_WAIT || VOP_ISLOCKED(vp, NULL) == 0)) {
1794 			return(0);	/* call scan2 */
1795 		}
1796 	}
1797 
1798 	/*
1799 	 * do not call scan2, continue the loop
1800 	 */
1801 	return(-1);
1802 }
1803 
1804 /*
1805  * This callback is handed a locked vnode.
1806  */
1807 static
1808 int
1809 vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data)
1810 {
1811 	vm_object_t obj;
1812 	int flags = (int)data;
1813 
1814 	if (vp->v_flag & VRECLAIMED)
1815 		return(0);
1816 
1817 	if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
1818 	    (vp->v_flag & VOBJDIRTY)) {
1819 		if (VOP_GETVOBJECT(vp, &obj) == 0) {
1820 			vm_object_page_clean(obj, 0, 0,
1821 			 flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
1822 		}
1823 	}
1824 	return(0);
1825 }
1826 
1827 /*
1828  * Create the VM object needed for VMIO and mmap support.  This
1829  * is done for all VREG files in the system.  Some filesystems might
1830  * afford the additional metadata buffering capability of the
1831  * VMIO code by making the device node be VMIO mode also.
1832  *
1833  * vp must be locked when vfs_object_create is called.
1834  */
1835 int
1836 vfs_object_create(struct vnode *vp, struct thread *td)
1837 {
1838 	return (VOP_CREATEVOBJECT(vp, td));
1839 }
1840 
1841 /*
1842  * Record a process's interest in events which might happen to
1843  * a vnode.  Because poll uses the historic select-style interface
1844  * internally, this routine serves as both the ``check for any
1845  * pending events'' and the ``record my interest in future events''
1846  * functions.  (These are done together, while the lock is held,
1847  * to avoid race conditions.)
1848  */
1849 int
1850 vn_pollrecord(struct vnode *vp, struct thread *td, int events)
1851 {
1852 	lwkt_tokref ilock;
1853 
1854 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
1855 	if (vp->v_pollinfo.vpi_revents & events) {
1856 		/*
1857 		 * This leaves events we are not interested
1858 		 * in available for the other process which
1859 		 * which presumably had requested them
1860 		 * (otherwise they would never have been
1861 		 * recorded).
1862 		 */
1863 		events &= vp->v_pollinfo.vpi_revents;
1864 		vp->v_pollinfo.vpi_revents &= ~events;
1865 
1866 		lwkt_reltoken(&ilock);
1867 		return events;
1868 	}
1869 	vp->v_pollinfo.vpi_events |= events;
1870 	selrecord(td, &vp->v_pollinfo.vpi_selinfo);
1871 	lwkt_reltoken(&ilock);
1872 	return 0;
1873 }
1874 
1875 /*
1876  * Note the occurrence of an event.  If the VN_POLLEVENT macro is used,
1877  * it is possible for us to miss an event due to race conditions, but
1878  * that condition is expected to be rare, so for the moment it is the
1879  * preferred interface.
1880  */
1881 void
1882 vn_pollevent(struct vnode *vp, int events)
1883 {
1884 	lwkt_tokref ilock;
1885 
1886 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
1887 	if (vp->v_pollinfo.vpi_events & events) {
1888 		/*
1889 		 * We clear vpi_events so that we don't
1890 		 * call selwakeup() twice if two events are
1891 		 * posted before the polling process(es) is
1892 		 * awakened.  This also ensures that we take at
1893 		 * most one selwakeup() if the polling process
1894 		 * is no longer interested.  However, it does
1895 		 * mean that only one event can be noticed at
1896 		 * a time.  (Perhaps we should only clear those
1897 		 * event bits which we note?) XXX
1898 		 */
1899 		vp->v_pollinfo.vpi_events = 0;	/* &= ~events ??? */
1900 		vp->v_pollinfo.vpi_revents |= events;
1901 		selwakeup(&vp->v_pollinfo.vpi_selinfo);
1902 	}
1903 	lwkt_reltoken(&ilock);
1904 }
1905 
1906 /*
1907  * Wake up anyone polling on vp because it is being revoked.
1908  * This depends on dead_poll() returning POLLHUP for correct
1909  * behavior.
1910  */
1911 void
1912 vn_pollgone(struct vnode *vp)
1913 {
1914 	lwkt_tokref ilock;
1915 
1916 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
1917 	if (vp->v_pollinfo.vpi_events) {
1918 		vp->v_pollinfo.vpi_events = 0;
1919 		selwakeup(&vp->v_pollinfo.vpi_selinfo);
1920 	}
1921 	lwkt_reltoken(&ilock);
1922 }
1923 
1924 /*
1925  * extract the dev_t from a VBLK or VCHR.  The vnode must have been opened
1926  * (or v_rdev might be NULL).
1927  */
1928 dev_t
1929 vn_todev(struct vnode *vp)
1930 {
1931 	if (vp->v_type != VBLK && vp->v_type != VCHR)
1932 		return (NODEV);
1933 	KKASSERT(vp->v_rdev != NULL);
1934 	return (vp->v_rdev);
1935 }
1936 
1937 /*
1938  * Check if vnode represents a disk device.  The vnode does not need to be
1939  * opened.
1940  */
1941 int
1942 vn_isdisk(struct vnode *vp, int *errp)
1943 {
1944 	dev_t dev;
1945 
1946 	if (vp->v_type != VBLK && vp->v_type != VCHR) {
1947 		if (errp != NULL)
1948 			*errp = ENOTBLK;
1949 		return (0);
1950 	}
1951 
1952 	if ((dev = vp->v_rdev) == NULL)
1953 		dev = udev2dev(vp->v_udev, (vp->v_type == VBLK));
1954 	if (dev == NULL || dev == NODEV) {
1955 		if (errp != NULL)
1956 			*errp = ENXIO;
1957 		return (0);
1958 	}
1959 	if (dev_is_good(dev) == 0) {
1960 		if (errp != NULL)
1961 			*errp = ENXIO;
1962 		return (0);
1963 	}
1964 	if ((dev_dflags(dev) & D_DISK) == 0) {
1965 		if (errp != NULL)
1966 			*errp = ENOTBLK;
1967 		return (0);
1968 	}
1969 	if (errp != NULL)
1970 		*errp = 0;
1971 	return (1);
1972 }
1973 
1974 #ifdef DEBUG_VFS_LOCKS
1975 
1976 void
1977 assert_vop_locked(struct vnode *vp, const char *str)
1978 {
1979 	if (vp && IS_LOCKING_VFS(vp) && !VOP_ISLOCKED(vp, NULL)) {
1980 		panic("%s: %p is not locked shared but should be", str, vp);
1981 	}
1982 }
1983 
1984 void
1985 assert_vop_unlocked(struct vnode *vp, const char *str)
1986 {
1987 	if (vp && IS_LOCKING_VFS(vp)) {
1988 		if (VOP_ISLOCKED(vp, curthread) == LK_EXCLUSIVE) {
1989 			panic("%s: %p is locked but should not be", str, vp);
1990 		}
1991 	}
1992 }
1993 
1994 #endif
1995 
1996 int
1997 vn_get_namelen(struct vnode *vp, int *namelen)
1998 {
1999 	int error, retval[2];
2000 
2001 	error = VOP_PATHCONF(vp, _PC_NAME_MAX, retval);
2002 	if (error)
2003 		return (error);
2004 	*namelen = *retval;
2005 	return (0);
2006 }
2007 
2008 int
2009 vop_write_dirent(int *error, struct uio *uio, ino_t d_ino, uint8_t d_type,
2010 		uint16_t d_namlen, const char *d_name)
2011 {
2012 	struct dirent *dp;
2013 	size_t len;
2014 
2015 	len = _DIRENT_RECLEN(d_namlen);
2016 	if (len > uio->uio_resid)
2017 		return(1);
2018 
2019 	dp = malloc(len, M_TEMP, M_WAITOK | M_ZERO);
2020 
2021 	dp->d_ino = d_ino;
2022 	dp->d_namlen = d_namlen;
2023 	dp->d_type = d_type;
2024 	bcopy(d_name, dp->d_name, d_namlen);
2025 
2026 	*error = uiomove((caddr_t)dp, len, uio);
2027 
2028 	free(dp, M_TEMP);
2029 
2030 	return(0);
2031 }
2032