xref: /dragonfly/sys/kern/vfs_subr.c (revision 40f79625)
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 1.70 2006/03/05 18:38:34 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_GENERATE2(buf_rb_tree, buf, b_rbnode, rb_buf_compare, daddr_t, b_lblkno);
140 RB_GENERATE2(buf_rb_hash, buf, b_rbhash, rb_buf_compare, daddr_t, b_lblkno);
141 
142 static int
143 rb_buf_compare(struct buf *b1, struct buf *b2)
144 {
145 	if (b1->b_lblkno < b2->b_lblkno)
146 		return(-1);
147 	if (b1->b_lblkno > b2->b_lblkno)
148 		return(1);
149 	return(0);
150 }
151 
152 /*
153  * Return 0 if the vnode is already on the free list or cannot be placed
154  * on the free list.  Return 1 if the vnode can be placed on the free list.
155  */
156 static __inline int
157 vshouldfree(struct vnode *vp, int usecount)
158 {
159 	if (vp->v_flag & VFREE)
160 		return (0);		/* already free */
161 	if (vp->v_holdcnt != 0 || vp->v_usecount != usecount)
162 		return (0);		/* other holderse */
163 	if (vp->v_object &&
164 	    (vp->v_object->ref_count || vp->v_object->resident_page_count)) {
165 		return (0);
166 	}
167 	return (1);
168 }
169 
170 /*
171  * Initialize the vnode management data structures.
172  *
173  * Called from vfsinit()
174  */
175 void
176 vfs_subr_init(void)
177 {
178 	/*
179 	 * Desired vnodes is a result of the physical page count
180 	 * and the size of kernel's heap.  It scales in proportion
181 	 * to the amount of available physical memory.  This can
182 	 * cause trouble on 64-bit and large memory platforms.
183 	 */
184 	/* desiredvnodes = maxproc + vmstats.v_page_count / 4; */
185 	desiredvnodes =
186 		min(maxproc + vmstats.v_page_count /4,
187 		    2 * (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) /
188 		    (5 * (sizeof(struct vm_object) + sizeof(struct vnode))));
189 
190 	lwkt_token_init(&spechash_token);
191 }
192 
193 /*
194  * Knob to control the precision of file timestamps:
195  *
196  *   0 = seconds only; nanoseconds zeroed.
197  *   1 = seconds and nanoseconds, accurate within 1/HZ.
198  *   2 = seconds and nanoseconds, truncated to microseconds.
199  * >=3 = seconds and nanoseconds, maximum precision.
200  */
201 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
202 
203 static int timestamp_precision = TSP_SEC;
204 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
205 		&timestamp_precision, 0, "");
206 
207 /*
208  * Get a current timestamp.
209  */
210 void
211 vfs_timestamp(struct timespec *tsp)
212 {
213 	struct timeval tv;
214 
215 	switch (timestamp_precision) {
216 	case TSP_SEC:
217 		tsp->tv_sec = time_second;
218 		tsp->tv_nsec = 0;
219 		break;
220 	case TSP_HZ:
221 		getnanotime(tsp);
222 		break;
223 	case TSP_USEC:
224 		microtime(&tv);
225 		TIMEVAL_TO_TIMESPEC(&tv, tsp);
226 		break;
227 	case TSP_NSEC:
228 	default:
229 		nanotime(tsp);
230 		break;
231 	}
232 }
233 
234 /*
235  * Set vnode attributes to VNOVAL
236  */
237 void
238 vattr_null(struct vattr *vap)
239 {
240 	vap->va_type = VNON;
241 	vap->va_size = VNOVAL;
242 	vap->va_bytes = VNOVAL;
243 	vap->va_mode = VNOVAL;
244 	vap->va_nlink = VNOVAL;
245 	vap->va_uid = VNOVAL;
246 	vap->va_gid = VNOVAL;
247 	vap->va_fsid = VNOVAL;
248 	vap->va_fileid = VNOVAL;
249 	vap->va_blocksize = VNOVAL;
250 	vap->va_rdev = VNOVAL;
251 	vap->va_atime.tv_sec = VNOVAL;
252 	vap->va_atime.tv_nsec = VNOVAL;
253 	vap->va_mtime.tv_sec = VNOVAL;
254 	vap->va_mtime.tv_nsec = VNOVAL;
255 	vap->va_ctime.tv_sec = VNOVAL;
256 	vap->va_ctime.tv_nsec = VNOVAL;
257 	vap->va_flags = VNOVAL;
258 	vap->va_gen = VNOVAL;
259 	vap->va_vaflags = 0;
260 	vap->va_fsmid = VNOVAL;
261 }
262 
263 /*
264  * Flush out and invalidate all buffers associated with a vnode.
265  *
266  * vp must be locked.
267  */
268 static int vinvalbuf_bp(struct buf *bp, void *data);
269 
270 struct vinvalbuf_bp_info {
271 	struct vnode *vp;
272 	int slptimeo;
273 	int lkflags;
274 	int flags;
275 };
276 
277 int
278 vinvalbuf(struct vnode *vp, int flags, struct thread *td,
279 	int slpflag, int slptimeo)
280 {
281 	struct vinvalbuf_bp_info info;
282 	int error;
283 	vm_object_t object;
284 
285 	/*
286 	 * If we are being asked to save, call fsync to ensure that the inode
287 	 * is updated.
288 	 */
289 	if (flags & V_SAVE) {
290 		crit_enter();
291 		while (vp->v_track_write.bk_active) {
292 			vp->v_track_write.bk_waitflag = 1;
293 			error = tsleep(&vp->v_track_write, slpflag,
294 					"vinvlbuf", slptimeo);
295 			if (error) {
296 				crit_exit();
297 				return (error);
298 			}
299 		}
300 		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
301 			crit_exit();
302 			if ((error = VOP_FSYNC(vp, MNT_WAIT, td)) != 0)
303 				return (error);
304 			crit_enter();
305 			if (vp->v_track_write.bk_active > 0 ||
306 			    !RB_EMPTY(&vp->v_rbdirty_tree))
307 				panic("vinvalbuf: dirty bufs");
308 		}
309 		crit_exit();
310   	}
311 	crit_enter();
312 	info.slptimeo = slptimeo;
313 	info.lkflags = LK_EXCLUSIVE | LK_SLEEPFAIL;
314 	if (slpflag & PCATCH)
315 		info.lkflags |= LK_PCATCH;
316 	info.flags = flags;
317 	info.vp = vp;
318 
319 	/*
320 	 * Flush the buffer cache until nothing is left.
321 	 */
322 	while (!RB_EMPTY(&vp->v_rbclean_tree) ||
323 	    !RB_EMPTY(&vp->v_rbdirty_tree)) {
324 		error = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree, NULL,
325 				vinvalbuf_bp, &info);
326 		if (error == 0) {
327 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
328 					vinvalbuf_bp, &info);
329 		}
330 	}
331 
332 	/*
333 	 * Wait for I/O to complete.  XXX needs cleaning up.  The vnode can
334 	 * have write I/O in-progress but if there is a VM object then the
335 	 * VM object can also have read-I/O in-progress.
336 	 */
337 	do {
338 		while (vp->v_track_write.bk_active > 0) {
339 			vp->v_track_write.bk_waitflag = 1;
340 			tsleep(&vp->v_track_write, 0, "vnvlbv", 0);
341 		}
342 		if (VOP_GETVOBJECT(vp, &object) == 0) {
343 			while (object->paging_in_progress)
344 				vm_object_pip_sleep(object, "vnvlbx");
345 		}
346 	} while (vp->v_track_write.bk_active > 0);
347 
348 	crit_exit();
349 
350 	/*
351 	 * Destroy the copy in the VM cache, too.
352 	 */
353 	if (VOP_GETVOBJECT(vp, &object) == 0) {
354 		vm_object_page_remove(object, 0, 0,
355 			(flags & V_SAVE) ? TRUE : FALSE);
356 	}
357 
358 	if (!RB_EMPTY(&vp->v_rbdirty_tree) || !RB_EMPTY(&vp->v_rbclean_tree))
359 		panic("vinvalbuf: flush failed");
360 	if (!RB_EMPTY(&vp->v_rbhash_tree))
361 		panic("vinvalbuf: flush failed, buffers still present");
362 	return (0);
363 }
364 
365 static int
366 vinvalbuf_bp(struct buf *bp, void *data)
367 {
368 	struct vinvalbuf_bp_info *info = data;
369 	int error;
370 
371 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
372 		error = BUF_TIMELOCK(bp, info->lkflags,
373 				     "vinvalbuf", info->slptimeo);
374 		if (error == 0) {
375 			BUF_UNLOCK(bp);
376 			error = ENOLCK;
377 		}
378 		if (error == ENOLCK)
379 			return(0);
380 		return (-error);
381 	}
382 
383 	KKASSERT(bp->b_vp == info->vp);
384 
385 	/*
386 	 * XXX Since there are no node locks for NFS, I
387 	 * believe there is a slight chance that a delayed
388 	 * write will occur while sleeping just above, so
389 	 * check for it.  Note that vfs_bio_awrite expects
390 	 * buffers to reside on a queue, while VOP_BWRITE and
391 	 * brelse do not.
392 	 */
393 	if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
394 	    (info->flags & V_SAVE)) {
395 		if (bp->b_vp == info->vp) {
396 			if (bp->b_flags & B_CLUSTEROK) {
397 				vfs_bio_awrite(bp);
398 			} else {
399 				bremfree(bp);
400 				bp->b_flags |= B_ASYNC;
401 				VOP_BWRITE(bp->b_vp, bp);
402 			}
403 		} else {
404 			bremfree(bp);
405 			VOP_BWRITE(bp->b_vp, bp);
406 		}
407 	} else {
408 		bremfree(bp);
409 		bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
410 		bp->b_flags &= ~B_ASYNC;
411 		brelse(bp);
412 	}
413 	return(0);
414 }
415 
416 /*
417  * Truncate a file's buffer and pages to a specified length.  This
418  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
419  * sync activity.
420  *
421  * The vnode must be locked.
422  */
423 static int vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data);
424 static int vtruncbuf_bp_trunc(struct buf *bp, void *data);
425 static int vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data);
426 static int vtruncbuf_bp_metasync(struct buf *bp, void *data);
427 
428 int
429 vtruncbuf(struct vnode *vp, struct thread *td, off_t length, int blksize)
430 {
431 	daddr_t trunclbn;
432 	int count;
433 
434 	/*
435 	 * Round up to the *next* lbn, then destroy the buffers in question.
436 	 * Since we are only removing some of the buffers we must rely on the
437 	 * scan count to determine whether a loop is necessary.
438 	 */
439 	trunclbn = (length + blksize - 1) / blksize;
440 
441 	crit_enter();
442 	do {
443 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
444 				vtruncbuf_bp_trunc_cmp,
445 				vtruncbuf_bp_trunc, &trunclbn);
446 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
447 				vtruncbuf_bp_trunc_cmp,
448 				vtruncbuf_bp_trunc, &trunclbn);
449 	} while(count);
450 
451 	/*
452 	 * For safety, fsync any remaining metadata if the file is not being
453 	 * truncated to 0.  Since the metadata does not represent the entire
454 	 * dirty list we have to rely on the hit count to ensure that we get
455 	 * all of it.
456 	 */
457 	if (length > 0) {
458 		do {
459 			count = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
460 					vtruncbuf_bp_metasync_cmp,
461 					vtruncbuf_bp_metasync, vp);
462 		} while (count);
463 	}
464 
465 	/*
466 	 * Wait for any in-progress I/O to complete before returning (why?)
467 	 */
468 	while (vp->v_track_write.bk_active > 0) {
469 		vp->v_track_write.bk_waitflag = 1;
470 		tsleep(&vp->v_track_write, 0, "vbtrunc", 0);
471 	}
472 
473 	crit_exit();
474 
475 	vnode_pager_setsize(vp, length);
476 
477 	return (0);
478 }
479 
480 /*
481  * The callback buffer is beyond the new file EOF and must be destroyed.
482  * Note that the compare function must conform to the RB_SCAN's requirements.
483  */
484 static
485 int
486 vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data)
487 {
488 	if (bp->b_lblkno >= *(daddr_t *)data)
489 		return(0);
490 	return(-1);
491 }
492 
493 static
494 int
495 vtruncbuf_bp_trunc(struct buf *bp, void *data)
496 {
497 	/*
498 	 * Do not try to use a buffer we cannot immediately lock, but sleep
499 	 * anyway to prevent a livelock.  The code will loop until all buffers
500 	 * can be acted upon.
501 	 */
502 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
503 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
504 			BUF_UNLOCK(bp);
505 	} else {
506 		bremfree(bp);
507 		bp->b_flags |= (B_INVAL | B_RELBUF);
508 		bp->b_flags &= ~B_ASYNC;
509 		brelse(bp);
510 	}
511 	return(1);
512 }
513 
514 /*
515  * Fsync all meta-data after truncating a file to be non-zero.  Only metadata
516  * blocks (with a negative lblkno) are scanned.
517  * Note that the compare function must conform to the RB_SCAN's requirements.
518  */
519 static int
520 vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data)
521 {
522 	if (bp->b_lblkno < 0)
523 		return(0);
524 	return(1);
525 }
526 
527 static int
528 vtruncbuf_bp_metasync(struct buf *bp, void *data)
529 {
530 	struct vnode *vp = data;
531 
532 	if (bp->b_flags & B_DELWRI) {
533 		/*
534 		 * Do not try to use a buffer we cannot immediately lock,
535 		 * but sleep anyway to prevent a livelock.  The code will
536 		 * loop until all buffers can be acted upon.
537 		 */
538 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
539 			if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
540 				BUF_UNLOCK(bp);
541 		} else {
542 			bremfree(bp);
543 			if (bp->b_vp == vp) {
544 				bp->b_flags |= B_ASYNC;
545 			} else {
546 				bp->b_flags &= ~B_ASYNC;
547 			}
548 			VOP_BWRITE(bp->b_vp, bp);
549 		}
550 		return(1);
551 	} else {
552 		return(0);
553 	}
554 }
555 
556 /*
557  * vfsync - implements a multipass fsync on a file which understands
558  * dependancies and meta-data.  The passed vnode must be locked.  The
559  * waitfor argument may be MNT_WAIT or MNT_NOWAIT, or MNT_LAZY.
560  *
561  * When fsyncing data asynchronously just do one consolidated pass starting
562  * with the most negative block number.  This may not get all the data due
563  * to dependancies.
564  *
565  * When fsyncing data synchronously do a data pass, then a metadata pass,
566  * then do additional data+metadata passes to try to get all the data out.
567  */
568 static int vfsync_wait_output(struct vnode *vp,
569 			    int (*waitoutput)(struct vnode *, struct thread *));
570 static int vfsync_data_only_cmp(struct buf *bp, void *data);
571 static int vfsync_meta_only_cmp(struct buf *bp, void *data);
572 static int vfsync_lazy_range_cmp(struct buf *bp, void *data);
573 static int vfsync_bp(struct buf *bp, void *data);
574 
575 struct vfsync_info {
576 	struct vnode *vp;
577 	int synchronous;
578 	int syncdeps;
579 	int lazycount;
580 	int lazylimit;
581 	daddr_t lbn;
582 	int (*checkdef)(struct buf *);
583 };
584 
585 int
586 vfsync(struct vnode *vp, int waitfor, int passes, daddr_t lbn,
587 	int (*checkdef)(struct buf *),
588 	int (*waitoutput)(struct vnode *, struct thread *))
589 {
590 	struct vfsync_info info;
591 	int error;
592 
593 	bzero(&info, sizeof(info));
594 	info.vp = vp;
595 	info.lbn = lbn;
596 	if ((info.checkdef = checkdef) == NULL)
597 		info.syncdeps = 1;
598 
599 	crit_enter();
600 
601 	switch(waitfor) {
602 	case MNT_LAZY:
603 		/*
604 		 * Lazy (filesystem syncer typ) Asynchronous plus limit the
605 		 * number of data (not meta) pages we try to flush to 1MB.
606 		 * A non-zero return means that lazy limit was reached.
607 		 */
608 		info.lazylimit = 1024 * 1024;
609 		info.syncdeps = 1;
610 		error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
611 				vfsync_lazy_range_cmp, vfsync_bp, &info);
612 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
613 				vfsync_meta_only_cmp, vfsync_bp, &info);
614 		if (error == 0)
615 			vp->v_lazyw = 0;
616 		else if (!RB_EMPTY(&vp->v_rbdirty_tree))
617 			vn_syncer_add_to_worklist(vp, 1);
618 		error = 0;
619 		break;
620 	case MNT_NOWAIT:
621 		/*
622 		 * Asynchronous.  Do a data-only pass and a meta-only pass.
623 		 */
624 		info.syncdeps = 1;
625 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
626 			vfsync_bp, &info);
627 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_meta_only_cmp,
628 			vfsync_bp, &info);
629 		error = 0;
630 		break;
631 	default:
632 		/*
633 		 * Synchronous.  Do a data-only pass, then a meta-data+data
634 		 * pass, then additional integrated passes to try to get
635 		 * all the dependancies flushed.
636 		 */
637 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
638 			vfsync_bp, &info);
639 		error = vfsync_wait_output(vp, waitoutput);
640 		if (error == 0) {
641 			RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
642 				vfsync_bp, &info);
643 			error = vfsync_wait_output(vp, waitoutput);
644 		}
645 		while (error == 0 && passes > 0 &&
646 		    !RB_EMPTY(&vp->v_rbdirty_tree)) {
647 			if (--passes == 0) {
648 				info.synchronous = 1;
649 				info.syncdeps = 1;
650 			}
651 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
652 				vfsync_bp, &info);
653 			if (error < 0)
654 				error = -error;
655 			info.syncdeps = 1;
656 			if (error == 0)
657 				error = vfsync_wait_output(vp, waitoutput);
658 		}
659 		break;
660 	}
661 	crit_exit();
662 	return(error);
663 }
664 
665 static int
666 vfsync_wait_output(struct vnode *vp, int (*waitoutput)(struct vnode *, struct thread *))
667 {
668 	int error = 0;
669 
670 	while (vp->v_track_write.bk_active) {
671 		vp->v_track_write.bk_waitflag = 1;
672 		tsleep(&vp->v_track_write, 0, "fsfsn", 0);
673 	}
674 	if (waitoutput)
675 		error = waitoutput(vp, curthread);
676 	return(error);
677 }
678 
679 static int
680 vfsync_data_only_cmp(struct buf *bp, void *data)
681 {
682 	if (bp->b_lblkno < 0)
683 		return(-1);
684 	return(0);
685 }
686 
687 static int
688 vfsync_meta_only_cmp(struct buf *bp, void *data)
689 {
690 	if (bp->b_lblkno < 0)
691 		return(0);
692 	return(1);
693 }
694 
695 static int
696 vfsync_lazy_range_cmp(struct buf *bp, void *data)
697 {
698 	struct vfsync_info *info = data;
699 	if (bp->b_lblkno < info->vp->v_lazyw)
700 		return(-1);
701 	return(0);
702 }
703 
704 static int
705 vfsync_bp(struct buf *bp, void *data)
706 {
707 	struct vfsync_info *info = data;
708 	struct vnode *vp = info->vp;
709 	int error;
710 
711 	/*
712 	 * if syncdeps is not set we do not try to write buffers which have
713 	 * dependancies.
714 	 */
715 	if (!info->synchronous && info->syncdeps == 0 && info->checkdef(bp))
716 		return(0);
717 
718 	/*
719 	 * Ignore buffers that we cannot immediately lock.  XXX
720 	 */
721 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT))
722 		return(0);
723 	if ((bp->b_flags & B_DELWRI) == 0)
724 		panic("vfsync_bp: buffer not dirty");
725 	if (vp != bp->b_vp)
726 		panic("vfsync_bp: buffer vp mismatch");
727 
728 	/*
729 	 * B_NEEDCOMMIT (primarily used by NFS) is a state where the buffer
730 	 * has been written but an additional handshake with the device
731 	 * is required before we can dispose of the buffer.  We have no idea
732 	 * how to do this so we have to skip these buffers.
733 	 */
734 	if (bp->b_flags & B_NEEDCOMMIT) {
735 		BUF_UNLOCK(bp);
736 		return(0);
737 	}
738 
739 	/*
740 	 * (LEGACY FROM UFS, REMOVE WHEN POSSIBLE) - invalidate any dirty
741 	 * buffers beyond the file EOF.
742 	 */
743 	if (info->lbn != (daddr_t)-1 && vp->v_type == VREG &&
744 	    bp->b_lblkno >= info->lbn) {
745 		bremfree(bp);
746 		bp->b_flags |= B_INVAL | B_NOCACHE;
747 		crit_exit();
748 		brelse(bp);
749 		crit_enter();
750 	}
751 
752 	if (info->synchronous) {
753 		/*
754 		 * Synchronous flushing.  An error may be returned.
755 		 */
756 		bremfree(bp);
757 		crit_exit();
758 		error = bwrite(bp);
759 		crit_enter();
760 	} else {
761 		/*
762 		 * Asynchronous flushing.  A negative return value simply
763 		 * stops the scan and is not considered an error.  We use
764 		 * this to support limited MNT_LAZY flushes.
765 		 */
766 		vp->v_lazyw = bp->b_lblkno;
767 		if ((vp->v_flag & VOBJBUF) && (bp->b_flags & B_CLUSTEROK)) {
768 			info->lazycount += vfs_bio_awrite(bp);
769 		} else {
770 			info->lazycount += bp->b_bufsize;
771 			bremfree(bp);
772 			crit_exit();
773 			bawrite(bp);
774 			crit_enter();
775 		}
776 		if (info->lazylimit && info->lazycount >= info->lazylimit)
777 			error = 1;
778 		else
779 			error = 0;
780 	}
781 	return(-error);
782 }
783 
784 /*
785  * Associate a buffer with a vnode.
786  */
787 void
788 bgetvp(struct vnode *vp, struct buf *bp)
789 {
790 	KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));
791 	KKASSERT((bp->b_flags & (B_HASHED|B_DELWRI)) == 0);
792 	KKASSERT((bp->b_xflags & (BX_VNCLEAN|BX_VNDIRTY)) == 0);
793 
794 	vhold(vp);
795 	/*
796 	 * Insert onto list for new vnode.
797 	 */
798 	crit_enter();
799 	bp->b_vp = vp;
800 	bp->b_flags |= B_HASHED;
801 	if (buf_rb_hash_RB_INSERT(&vp->v_rbhash_tree, bp))
802 		panic("reassignbuf: dup lblk vp %p bp %p", vp, bp);
803 
804 	bp->b_xflags |= BX_VNCLEAN;
805 	if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp))
806 		panic("reassignbuf: dup lblk/clean vp %p bp %p", vp, bp);
807 	crit_exit();
808 }
809 
810 /*
811  * Disassociate a buffer from a vnode.
812  */
813 void
814 brelvp(struct buf *bp)
815 {
816 	struct vnode *vp;
817 
818 	KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
819 
820 	/*
821 	 * Delete from old vnode list, if on one.
822 	 */
823 	vp = bp->b_vp;
824 	crit_enter();
825 	if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) {
826 		if (bp->b_xflags & BX_VNDIRTY)
827 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
828 		else
829 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
830 		bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
831 	}
832 	if (bp->b_flags & B_HASHED) {
833 		buf_rb_hash_RB_REMOVE(&vp->v_rbhash_tree, bp);
834 		bp->b_flags &= ~B_HASHED;
835 	}
836 	if ((vp->v_flag & VONWORKLST) && RB_EMPTY(&vp->v_rbdirty_tree)) {
837 		vp->v_flag &= ~VONWORKLST;
838 		LIST_REMOVE(vp, v_synclist);
839 	}
840 	crit_exit();
841 	bp->b_vp = NULL;
842 	vdrop(vp);
843 }
844 
845 /*
846  * Associate a p-buffer with a vnode.
847  *
848  * Also sets B_PAGING flag to indicate that vnode is not fully associated
849  * with the buffer.  i.e. the bp has not been linked into the vnode or
850  * ref-counted.
851  */
852 void
853 pbgetvp(struct vnode *vp, struct buf *bp)
854 {
855 	KASSERT(bp->b_vp == NULL, ("pbgetvp: not free"));
856 	KKASSERT((bp->b_flags & B_HASHED) == 0);
857 
858 	bp->b_vp = vp;
859 	bp->b_flags |= B_PAGING;
860 }
861 
862 /*
863  * Disassociate a p-buffer from a vnode.
864  */
865 void
866 pbrelvp(struct buf *bp)
867 {
868 	KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL"));
869 	KKASSERT((bp->b_flags & B_HASHED) == 0);
870 
871 	bp->b_vp = NULL;
872 	bp->b_flags &= ~B_PAGING;
873 }
874 
875 /*
876  * Reassign the buffer to the proper clean/dirty list based on B_DELWRI.
877  * This routine is called when the state of the B_DELWRI bit is changed.
878  */
879 void
880 reassignbuf(struct buf *bp)
881 {
882 	struct vnode *vp = bp->b_vp;
883 	int delay;
884 
885 	KKASSERT(vp != NULL);
886 	++reassignbufcalls;
887 
888 	/*
889 	 * B_PAGING flagged buffers cannot be reassigned because their vp
890 	 * is not fully linked in.
891 	 */
892 	if (bp->b_flags & B_PAGING)
893 		panic("cannot reassign paging buffer");
894 
895 	crit_enter();
896 	if (bp->b_flags & B_DELWRI) {
897 		/*
898 		 * Move to the dirty list, add the vnode to the worklist
899 		 */
900 		if (bp->b_xflags & BX_VNCLEAN) {
901 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
902 			bp->b_xflags &= ~BX_VNCLEAN;
903 		}
904 		if ((bp->b_xflags & BX_VNDIRTY) == 0) {
905 			if (buf_rb_tree_RB_INSERT(&vp->v_rbdirty_tree, bp)) {
906 				panic("reassignbuf: dup lblk vp %p bp %p",
907 				      vp, bp);
908 			}
909 			bp->b_xflags |= BX_VNDIRTY;
910 		}
911 		if ((vp->v_flag & VONWORKLST) == 0) {
912 			switch (vp->v_type) {
913 			case VDIR:
914 				delay = dirdelay;
915 				break;
916 			case VCHR:
917 			case VBLK:
918 				if (vp->v_rdev &&
919 				    vp->v_rdev->si_mountpoint != NULL) {
920 					delay = metadelay;
921 					break;
922 				}
923 				/* fall through */
924 			default:
925 				delay = filedelay;
926 			}
927 			vn_syncer_add_to_worklist(vp, delay);
928 		}
929 	} else {
930 		/*
931 		 * Move to the clean list, remove the vnode from the worklist
932 		 * if no dirty blocks remain.
933 		 */
934 		if (bp->b_xflags & BX_VNDIRTY) {
935 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
936 			bp->b_xflags &= ~BX_VNDIRTY;
937 		}
938 		if ((bp->b_xflags & BX_VNCLEAN) == 0) {
939 			if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp)) {
940 				panic("reassignbuf: dup lblk vp %p bp %p",
941 				      vp, bp);
942 			}
943 			bp->b_xflags |= BX_VNCLEAN;
944 		}
945 		if ((vp->v_flag & VONWORKLST) &&
946 		    RB_EMPTY(&vp->v_rbdirty_tree)) {
947 			vp->v_flag &= ~VONWORKLST;
948 			LIST_REMOVE(vp, v_synclist);
949 		}
950 	}
951 	crit_exit();
952 }
953 
954 /*
955  * Create a vnode for a block device.
956  * Used for mounting the root file system.
957  */
958 int
959 bdevvp(dev_t dev, struct vnode **vpp)
960 {
961 	struct vnode *vp;
962 	struct vnode *nvp;
963 	int error;
964 
965 	if (dev == NODEV) {
966 		*vpp = NULLVP;
967 		return (ENXIO);
968 	}
969 	error = getspecialvnode(VT_NON, NULL, &spec_vnode_vops, &nvp, 0, 0);
970 	if (error) {
971 		*vpp = NULLVP;
972 		return (error);
973 	}
974 	vp = nvp;
975 	vp->v_type = VCHR;
976 	vp->v_udev = dev->si_udev;
977 	vx_unlock(vp);
978 	*vpp = vp;
979 	return (0);
980 }
981 
982 int
983 v_associate_rdev(struct vnode *vp, dev_t dev)
984 {
985 	lwkt_tokref ilock;
986 
987 	if (dev == NULL || dev == NODEV)
988 		return(ENXIO);
989 	if (dev_is_good(dev) == 0)
990 		return(ENXIO);
991 	KKASSERT(vp->v_rdev == NULL);
992 	if (dev_ref_debug)
993 		printf("Z1");
994 	vp->v_rdev = reference_dev(dev);
995 	lwkt_gettoken(&ilock, &spechash_token);
996 	SLIST_INSERT_HEAD(&dev->si_hlist, vp, v_specnext);
997 	lwkt_reltoken(&ilock);
998 	return(0);
999 }
1000 
1001 void
1002 v_release_rdev(struct vnode *vp)
1003 {
1004 	lwkt_tokref ilock;
1005 	dev_t dev;
1006 
1007 	if ((dev = vp->v_rdev) != NULL) {
1008 		lwkt_gettoken(&ilock, &spechash_token);
1009 		SLIST_REMOVE(&dev->si_hlist, vp, vnode, v_specnext);
1010 		if (dev_ref_debug && vp->v_opencount != 0) {
1011 			printf("releasing rdev with non-0 "
1012 				"v_opencount(%d) (revoked?)\n",
1013 				vp->v_opencount);
1014 		}
1015 		vp->v_rdev = NULL;
1016 		vp->v_opencount = 0;
1017 		release_dev(dev);
1018 		lwkt_reltoken(&ilock);
1019 	}
1020 }
1021 
1022 /*
1023  * Add a vnode to the alias list hung off the dev_t.  We only associate
1024  * the device number with the vnode.  The actual device is not associated
1025  * until the vnode is opened (usually in spec_open()), and will be
1026  * disassociated on last close.
1027  */
1028 void
1029 addaliasu(struct vnode *nvp, udev_t nvp_udev)
1030 {
1031 	if (nvp->v_type != VBLK && nvp->v_type != VCHR)
1032 		panic("addaliasu on non-special vnode");
1033 	nvp->v_udev = nvp_udev;
1034 }
1035 
1036 /*
1037  * Disassociate a vnode from its underlying filesystem.
1038  *
1039  * The vnode must be VX locked and refd
1040  *
1041  * If there are v_usecount references to the vnode other then ours we have
1042  * to VOP_CLOSE the vnode before we can deactivate and reclaim it.
1043  */
1044 void
1045 vclean(struct vnode *vp, int flags, struct thread *td)
1046 {
1047 	int active;
1048 	int retflags = 0;
1049 
1050 	/*
1051 	 * If the vnode has already been reclaimed we have nothing to do.
1052 	 */
1053 	if (vp->v_flag & VRECLAIMED)
1054 		return;
1055 	vp->v_flag |= VRECLAIMED;
1056 
1057 	/*
1058 	 * Scrap the vfs cache
1059 	 */
1060 	while (cache_inval_vp(vp, 0, &retflags) != 0) {
1061 		printf("Warning: vnode %p clean/cache_resolution race detected\n", vp);
1062 		tsleep(vp, 0, "vclninv", 2);
1063 	}
1064 
1065 	/*
1066 	 * Check to see if the vnode is in use. If so we have to reference it
1067 	 * before we clean it out so that its count cannot fall to zero and
1068 	 * generate a race against ourselves to recycle it.
1069 	 */
1070 	active = (vp->v_usecount > 1);
1071 
1072 	/*
1073 	 * Clean out any buffers associated with the vnode and destroy its
1074 	 * object, if it has one.
1075 	 */
1076 	vinvalbuf(vp, V_SAVE, td, 0, 0);
1077 	VOP_DESTROYVOBJECT(vp);
1078 
1079 	/*
1080 	 * If purging an active vnode, it must be closed and
1081 	 * deactivated before being reclaimed.   XXX
1082 	 *
1083 	 * Note that neither of these routines unlocks the vnode.
1084 	 */
1085 	if (active) {
1086 		if (flags & DOCLOSE)
1087 			VOP_CLOSE(vp, FNONBLOCK, td);
1088 	}
1089 
1090 	/*
1091 	 * If the vnode has not be deactivated, deactivated it.
1092 	 */
1093 	if ((vp->v_flag & VINACTIVE) == 0) {
1094 		vp->v_flag |= VINACTIVE;
1095 		VOP_INACTIVE(vp, td);
1096 	}
1097 
1098 	/*
1099 	 * Reclaim the vnode.
1100 	 */
1101 	if (VOP_RECLAIM(vp, retflags, td))
1102 		panic("vclean: cannot reclaim");
1103 
1104 	/*
1105 	 * Done with purge, notify sleepers of the grim news.
1106 	 */
1107 	vp->v_ops = &dead_vnode_vops;
1108 	vn_pollgone(vp);
1109 	vp->v_tag = VT_NON;
1110 }
1111 
1112 /*
1113  * Eliminate all activity associated with the requested vnode
1114  * and with all vnodes aliased to the requested vnode.
1115  *
1116  * The vnode must be referenced and vx_lock()'d
1117  *
1118  * revoke { struct vnode *a_vp, int a_flags }
1119  */
1120 int
1121 vop_stdrevoke(struct vop_revoke_args *ap)
1122 {
1123 	struct vnode *vp, *vq;
1124 	lwkt_tokref ilock;
1125 	dev_t dev;
1126 
1127 	KASSERT((ap->a_flags & REVOKEALL) != 0, ("vop_revoke"));
1128 
1129 	vp = ap->a_vp;
1130 
1131 	/*
1132 	 * If the vnode is already dead don't try to revoke it
1133 	 */
1134 	if (vp->v_flag & VRECLAIMED)
1135 		return (0);
1136 
1137 	/*
1138 	 * If the vnode has a device association, scrap all vnodes associated
1139 	 * with the device.  Don't let the device disappear on us while we
1140 	 * are scrapping the vnodes.
1141 	 *
1142 	 * The passed vp will probably show up in the list, do not VX lock
1143 	 * it twice!
1144 	 */
1145 	if (vp->v_type != VCHR && vp->v_type != VBLK)
1146 		return(0);
1147 	if ((dev = vp->v_rdev) == NULL) {
1148 		if ((dev = udev2dev(vp->v_udev, vp->v_type == VBLK)) == NODEV)
1149 			return(0);
1150 	}
1151 	reference_dev(dev);
1152 	lwkt_gettoken(&ilock, &spechash_token);
1153 	while ((vq = SLIST_FIRST(&dev->si_hlist)) != NULL) {
1154 		if (vp == vq || vx_get(vq) == 0) {
1155 			if (vq == SLIST_FIRST(&dev->si_hlist))
1156 				vgone(vq);
1157 			if (vp != vq)
1158 				vx_put(vq);
1159 		}
1160 	}
1161 	lwkt_reltoken(&ilock);
1162 	release_dev(dev);
1163 	return (0);
1164 }
1165 
1166 /*
1167  * Recycle an unused vnode to the front of the free list.
1168  *
1169  * Returns 1 if we were successfully able to recycle the vnode,
1170  * 0 otherwise.
1171  */
1172 int
1173 vrecycle(struct vnode *vp, struct thread *td)
1174 {
1175 	if (vp->v_usecount == 1) {
1176 		vgone(vp);
1177 		return (1);
1178 	}
1179 	return (0);
1180 }
1181 
1182 /*
1183  * Eliminate all activity associated with a vnode in preparation for reuse.
1184  *
1185  * The vnode must be VX locked and refd and will remain VX locked and refd
1186  * on return.  This routine may be called with the vnode in any state, as
1187  * long as it is VX locked.  The vnode will be cleaned out and marked
1188  * VRECLAIMED but will not actually be reused until all existing refs and
1189  * holds go away.
1190  *
1191  * NOTE: This routine may be called on a vnode which has not yet been
1192  * already been deactivated (VOP_INACTIVE), or on a vnode which has
1193  * already been reclaimed.
1194  *
1195  * This routine is not responsible for placing us back on the freelist.
1196  * Instead, it happens automatically when the caller releases the VX lock
1197  * (assuming there aren't any other references).
1198  */
1199 void
1200 vgone(struct vnode *vp)
1201 {
1202 	/*
1203 	 * assert that the VX lock is held.  This is an absolute requirement
1204 	 * now for vgone() to be called.
1205 	 */
1206 	KKASSERT(vp->v_lock.lk_exclusivecount == 1);
1207 
1208 	/*
1209 	 * Clean out the filesystem specific data and set the VRECLAIMED
1210 	 * bit.  Also deactivate the vnode if necessary.
1211 	 */
1212 	vclean(vp, DOCLOSE, curthread);
1213 
1214 	/*
1215 	 * Delete from old mount point vnode list, if on one.
1216 	 */
1217 	if (vp->v_mount != NULL)
1218 		insmntque(vp, NULL);
1219 
1220 	/*
1221 	 * If special device, remove it from special device alias list
1222 	 * if it is on one.  This should normally only occur if a vnode is
1223 	 * being revoked as the device should otherwise have been released
1224 	 * naturally.
1225 	 */
1226 	if ((vp->v_type == VBLK || vp->v_type == VCHR) && vp->v_rdev != NULL) {
1227 		v_release_rdev(vp);
1228 	}
1229 
1230 	/*
1231 	 * Set us to VBAD
1232 	 */
1233 	vp->v_type = VBAD;
1234 }
1235 
1236 /*
1237  * Lookup a vnode by device number.
1238  */
1239 int
1240 vfinddev(dev_t dev, enum vtype type, struct vnode **vpp)
1241 {
1242 	lwkt_tokref ilock;
1243 	struct vnode *vp;
1244 
1245 	lwkt_gettoken(&ilock, &spechash_token);
1246 	SLIST_FOREACH(vp, &dev->si_hlist, v_specnext) {
1247 		if (type == vp->v_type) {
1248 			*vpp = vp;
1249 			lwkt_reltoken(&ilock);
1250 			return (1);
1251 		}
1252 	}
1253 	lwkt_reltoken(&ilock);
1254 	return (0);
1255 }
1256 
1257 /*
1258  * Calculate the total number of references to a special device.  This
1259  * routine may only be called for VBLK and VCHR vnodes since v_rdev is
1260  * an overloaded field.  Since udev2dev can now return NODEV, we have
1261  * to check for a NULL v_rdev.
1262  */
1263 int
1264 count_dev(dev_t dev)
1265 {
1266 	lwkt_tokref ilock;
1267 	struct vnode *vp;
1268 	int count = 0;
1269 
1270 	if (SLIST_FIRST(&dev->si_hlist)) {
1271 		lwkt_gettoken(&ilock, &spechash_token);
1272 		SLIST_FOREACH(vp, &dev->si_hlist, v_specnext) {
1273 			count += vp->v_usecount;
1274 		}
1275 		lwkt_reltoken(&ilock);
1276 	}
1277 	return(count);
1278 }
1279 
1280 int
1281 count_udev(udev_t udev)
1282 {
1283 	dev_t dev;
1284 
1285 	if ((dev = udev2dev(udev, 0)) == NODEV)
1286 		return(0);
1287 	return(count_dev(dev));
1288 }
1289 
1290 int
1291 vcount(struct vnode *vp)
1292 {
1293 	if (vp->v_rdev == NULL)
1294 		return(0);
1295 	return(count_dev(vp->v_rdev));
1296 }
1297 
1298 /*
1299  * Print out a description of a vnode.
1300  */
1301 static char *typename[] =
1302 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
1303 
1304 void
1305 vprint(char *label, struct vnode *vp)
1306 {
1307 	char buf[96];
1308 
1309 	if (label != NULL)
1310 		printf("%s: %p: ", label, (void *)vp);
1311 	else
1312 		printf("%p: ", (void *)vp);
1313 	printf("type %s, usecount %d, writecount %d, refcount %d,",
1314 	    typename[vp->v_type], vp->v_usecount, vp->v_writecount,
1315 	    vp->v_holdcnt);
1316 	buf[0] = '\0';
1317 	if (vp->v_flag & VROOT)
1318 		strcat(buf, "|VROOT");
1319 	if (vp->v_flag & VTEXT)
1320 		strcat(buf, "|VTEXT");
1321 	if (vp->v_flag & VSYSTEM)
1322 		strcat(buf, "|VSYSTEM");
1323 	if (vp->v_flag & VFREE)
1324 		strcat(buf, "|VFREE");
1325 	if (vp->v_flag & VOBJBUF)
1326 		strcat(buf, "|VOBJBUF");
1327 	if (buf[0] != '\0')
1328 		printf(" flags (%s)", &buf[1]);
1329 	if (vp->v_data == NULL) {
1330 		printf("\n");
1331 	} else {
1332 		printf("\n\t");
1333 		VOP_PRINT(vp);
1334 	}
1335 }
1336 
1337 #ifdef DDB
1338 #include <ddb/ddb.h>
1339 
1340 static int db_show_locked_vnodes(struct mount *mp, void *data);
1341 
1342 /*
1343  * List all of the locked vnodes in the system.
1344  * Called when debugging the kernel.
1345  */
1346 DB_SHOW_COMMAND(lockedvnodes, lockedvnodes)
1347 {
1348 	printf("Locked vnodes\n");
1349 	mountlist_scan(db_show_locked_vnodes, NULL,
1350 			MNTSCAN_FORWARD|MNTSCAN_NOBUSY);
1351 }
1352 
1353 static int
1354 db_show_locked_vnodes(struct mount *mp, void *data __unused)
1355 {
1356 	struct vnode *vp;
1357 
1358 	TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
1359 		if (VOP_ISLOCKED(vp, NULL))
1360 			vprint((char *)0, vp);
1361 	}
1362 	return(0);
1363 }
1364 #endif
1365 
1366 /*
1367  * Top level filesystem related information gathering.
1368  */
1369 static int	sysctl_ovfs_conf (SYSCTL_HANDLER_ARGS);
1370 
1371 static int
1372 vfs_sysctl(SYSCTL_HANDLER_ARGS)
1373 {
1374 	int *name = (int *)arg1 - 1;	/* XXX */
1375 	u_int namelen = arg2 + 1;	/* XXX */
1376 	struct vfsconf *vfsp;
1377 
1378 #if 1 || defined(COMPAT_PRELITE2)
1379 	/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
1380 	if (namelen == 1)
1381 		return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
1382 #endif
1383 
1384 #ifdef notyet
1385 	/* all sysctl names at this level are at least name and field */
1386 	if (namelen < 2)
1387 		return (ENOTDIR);		/* overloaded */
1388 	if (name[0] != VFS_GENERIC) {
1389 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
1390 			if (vfsp->vfc_typenum == name[0])
1391 				break;
1392 		if (vfsp == NULL)
1393 			return (EOPNOTSUPP);
1394 		return ((*vfsp->vfc_vfsops->vfs_sysctl)(&name[1], namelen - 1,
1395 		    oldp, oldlenp, newp, newlen, p));
1396 	}
1397 #endif
1398 	switch (name[1]) {
1399 	case VFS_MAXTYPENUM:
1400 		if (namelen != 2)
1401 			return (ENOTDIR);
1402 		return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
1403 	case VFS_CONF:
1404 		if (namelen != 3)
1405 			return (ENOTDIR);	/* overloaded */
1406 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
1407 			if (vfsp->vfc_typenum == name[2])
1408 				break;
1409 		if (vfsp == NULL)
1410 			return (EOPNOTSUPP);
1411 		return (SYSCTL_OUT(req, vfsp, sizeof *vfsp));
1412 	}
1413 	return (EOPNOTSUPP);
1414 }
1415 
1416 SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD, vfs_sysctl,
1417 	"Generic filesystem");
1418 
1419 #if 1 || defined(COMPAT_PRELITE2)
1420 
1421 static int
1422 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
1423 {
1424 	int error;
1425 	struct vfsconf *vfsp;
1426 	struct ovfsconf ovfs;
1427 
1428 	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
1429 		bzero(&ovfs, sizeof(ovfs));
1430 		ovfs.vfc_vfsops = vfsp->vfc_vfsops;	/* XXX used as flag */
1431 		strcpy(ovfs.vfc_name, vfsp->vfc_name);
1432 		ovfs.vfc_index = vfsp->vfc_typenum;
1433 		ovfs.vfc_refcount = vfsp->vfc_refcount;
1434 		ovfs.vfc_flags = vfsp->vfc_flags;
1435 		error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
1436 		if (error)
1437 			return error;
1438 	}
1439 	return 0;
1440 }
1441 
1442 #endif /* 1 || COMPAT_PRELITE2 */
1443 
1444 /*
1445  * Check to see if a filesystem is mounted on a block device.
1446  */
1447 int
1448 vfs_mountedon(struct vnode *vp)
1449 {
1450 	dev_t dev;
1451 
1452 	if ((dev = vp->v_rdev) == NULL)
1453 		dev = udev2dev(vp->v_udev, (vp->v_type == VBLK));
1454 	if (dev != NODEV && dev->si_mountpoint)
1455 		return (EBUSY);
1456 	return (0);
1457 }
1458 
1459 /*
1460  * Unmount all filesystems. The list is traversed in reverse order
1461  * of mounting to avoid dependencies.
1462  */
1463 
1464 static int vfs_umountall_callback(struct mount *mp, void *data);
1465 
1466 void
1467 vfs_unmountall(void)
1468 {
1469 	struct thread *td = curthread;
1470 	int count;
1471 
1472 	if (td->td_proc == NULL)
1473 		td = initproc->p_thread;	/* XXX XXX use proc0 instead? */
1474 
1475 	do {
1476 		count = mountlist_scan(vfs_umountall_callback,
1477 					&td, MNTSCAN_REVERSE|MNTSCAN_NOBUSY);
1478 	} while (count);
1479 }
1480 
1481 static
1482 int
1483 vfs_umountall_callback(struct mount *mp, void *data)
1484 {
1485 	struct thread *td = *(struct thread **)data;
1486 	int error;
1487 
1488 	error = dounmount(mp, MNT_FORCE, td);
1489 	if (error) {
1490 		mountlist_remove(mp);
1491 		printf("unmount of filesystem mounted from %s failed (",
1492 			mp->mnt_stat.f_mntfromname);
1493 		if (error == EBUSY)
1494 			printf("BUSY)\n");
1495 		else
1496 			printf("%d)\n", error);
1497 	}
1498 	return(1);
1499 }
1500 
1501 /*
1502  * Build hash lists of net addresses and hang them off the mount point.
1503  * Called by ufs_mount() to set up the lists of export addresses.
1504  */
1505 static int
1506 vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
1507 		struct export_args *argp)
1508 {
1509 	struct netcred *np;
1510 	struct radix_node_head *rnh;
1511 	int i;
1512 	struct radix_node *rn;
1513 	struct sockaddr *saddr, *smask = 0;
1514 	struct domain *dom;
1515 	int error;
1516 
1517 	if (argp->ex_addrlen == 0) {
1518 		if (mp->mnt_flag & MNT_DEFEXPORTED)
1519 			return (EPERM);
1520 		np = &nep->ne_defexported;
1521 		np->netc_exflags = argp->ex_flags;
1522 		np->netc_anon = argp->ex_anon;
1523 		np->netc_anon.cr_ref = 1;
1524 		mp->mnt_flag |= MNT_DEFEXPORTED;
1525 		return (0);
1526 	}
1527 
1528 	if (argp->ex_addrlen < 0 || argp->ex_addrlen > MLEN)
1529 		return (EINVAL);
1530 	if (argp->ex_masklen < 0 || argp->ex_masklen > MLEN)
1531 		return (EINVAL);
1532 
1533 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
1534 	np = (struct netcred *) malloc(i, M_NETADDR, M_WAITOK);
1535 	bzero((caddr_t) np, i);
1536 	saddr = (struct sockaddr *) (np + 1);
1537 	if ((error = copyin(argp->ex_addr, (caddr_t) saddr, argp->ex_addrlen)))
1538 		goto out;
1539 	if (saddr->sa_len > argp->ex_addrlen)
1540 		saddr->sa_len = argp->ex_addrlen;
1541 	if (argp->ex_masklen) {
1542 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
1543 		error = copyin(argp->ex_mask, (caddr_t)smask, argp->ex_masklen);
1544 		if (error)
1545 			goto out;
1546 		if (smask->sa_len > argp->ex_masklen)
1547 			smask->sa_len = argp->ex_masklen;
1548 	}
1549 	i = saddr->sa_family;
1550 	if ((rnh = nep->ne_rtable[i]) == 0) {
1551 		/*
1552 		 * Seems silly to initialize every AF when most are not used,
1553 		 * do so on demand here
1554 		 */
1555 		SLIST_FOREACH(dom, &domains, dom_next)
1556 			if (dom->dom_family == i && dom->dom_rtattach) {
1557 				dom->dom_rtattach((void **) &nep->ne_rtable[i],
1558 				    dom->dom_rtoffset);
1559 				break;
1560 			}
1561 		if ((rnh = nep->ne_rtable[i]) == 0) {
1562 			error = ENOBUFS;
1563 			goto out;
1564 		}
1565 	}
1566 	rn = (*rnh->rnh_addaddr) ((char *) saddr, (char *) smask, rnh,
1567 	    np->netc_rnodes);
1568 	if (rn == 0 || np != (struct netcred *) rn) {	/* already exists */
1569 		error = EPERM;
1570 		goto out;
1571 	}
1572 	np->netc_exflags = argp->ex_flags;
1573 	np->netc_anon = argp->ex_anon;
1574 	np->netc_anon.cr_ref = 1;
1575 	return (0);
1576 out:
1577 	free(np, M_NETADDR);
1578 	return (error);
1579 }
1580 
1581 /* ARGSUSED */
1582 static int
1583 vfs_free_netcred(struct radix_node *rn, void *w)
1584 {
1585 	struct radix_node_head *rnh = (struct radix_node_head *) w;
1586 
1587 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
1588 	free((caddr_t) rn, M_NETADDR);
1589 	return (0);
1590 }
1591 
1592 /*
1593  * Free the net address hash lists that are hanging off the mount points.
1594  */
1595 static void
1596 vfs_free_addrlist(struct netexport *nep)
1597 {
1598 	int i;
1599 	struct radix_node_head *rnh;
1600 
1601 	for (i = 0; i <= AF_MAX; i++)
1602 		if ((rnh = nep->ne_rtable[i])) {
1603 			(*rnh->rnh_walktree) (rnh, vfs_free_netcred,
1604 			    (caddr_t) rnh);
1605 			free((caddr_t) rnh, M_RTABLE);
1606 			nep->ne_rtable[i] = 0;
1607 		}
1608 }
1609 
1610 int
1611 vfs_export(struct mount *mp, struct netexport *nep, struct export_args *argp)
1612 {
1613 	int error;
1614 
1615 	if (argp->ex_flags & MNT_DELEXPORT) {
1616 		if (mp->mnt_flag & MNT_EXPUBLIC) {
1617 			vfs_setpublicfs(NULL, NULL, NULL);
1618 			mp->mnt_flag &= ~MNT_EXPUBLIC;
1619 		}
1620 		vfs_free_addrlist(nep);
1621 		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
1622 	}
1623 	if (argp->ex_flags & MNT_EXPORTED) {
1624 		if (argp->ex_flags & MNT_EXPUBLIC) {
1625 			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
1626 				return (error);
1627 			mp->mnt_flag |= MNT_EXPUBLIC;
1628 		}
1629 		if ((error = vfs_hang_addrlist(mp, nep, argp)))
1630 			return (error);
1631 		mp->mnt_flag |= MNT_EXPORTED;
1632 	}
1633 	return (0);
1634 }
1635 
1636 
1637 /*
1638  * Set the publicly exported filesystem (WebNFS). Currently, only
1639  * one public filesystem is possible in the spec (RFC 2054 and 2055)
1640  */
1641 int
1642 vfs_setpublicfs(struct mount *mp, struct netexport *nep,
1643 		struct export_args *argp)
1644 {
1645 	int error;
1646 	struct vnode *rvp;
1647 	char *cp;
1648 
1649 	/*
1650 	 * mp == NULL -> invalidate the current info, the FS is
1651 	 * no longer exported. May be called from either vfs_export
1652 	 * or unmount, so check if it hasn't already been done.
1653 	 */
1654 	if (mp == NULL) {
1655 		if (nfs_pub.np_valid) {
1656 			nfs_pub.np_valid = 0;
1657 			if (nfs_pub.np_index != NULL) {
1658 				FREE(nfs_pub.np_index, M_TEMP);
1659 				nfs_pub.np_index = NULL;
1660 			}
1661 		}
1662 		return (0);
1663 	}
1664 
1665 	/*
1666 	 * Only one allowed at a time.
1667 	 */
1668 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
1669 		return (EBUSY);
1670 
1671 	/*
1672 	 * Get real filehandle for root of exported FS.
1673 	 */
1674 	bzero((caddr_t)&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
1675 	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
1676 
1677 	if ((error = VFS_ROOT(mp, &rvp)))
1678 		return (error);
1679 
1680 	if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
1681 		return (error);
1682 
1683 	vput(rvp);
1684 
1685 	/*
1686 	 * If an indexfile was specified, pull it in.
1687 	 */
1688 	if (argp->ex_indexfile != NULL) {
1689 		int namelen;
1690 
1691 		error = vn_get_namelen(rvp, &namelen);
1692 		if (error)
1693 			return (error);
1694 		MALLOC(nfs_pub.np_index, char *, namelen, M_TEMP,
1695 		    M_WAITOK);
1696 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
1697 		    namelen, (size_t *)0);
1698 		if (!error) {
1699 			/*
1700 			 * Check for illegal filenames.
1701 			 */
1702 			for (cp = nfs_pub.np_index; *cp; cp++) {
1703 				if (*cp == '/') {
1704 					error = EINVAL;
1705 					break;
1706 				}
1707 			}
1708 		}
1709 		if (error) {
1710 			FREE(nfs_pub.np_index, M_TEMP);
1711 			return (error);
1712 		}
1713 	}
1714 
1715 	nfs_pub.np_mount = mp;
1716 	nfs_pub.np_valid = 1;
1717 	return (0);
1718 }
1719 
1720 struct netcred *
1721 vfs_export_lookup(struct mount *mp, struct netexport *nep,
1722 		struct sockaddr *nam)
1723 {
1724 	struct netcred *np;
1725 	struct radix_node_head *rnh;
1726 	struct sockaddr *saddr;
1727 
1728 	np = NULL;
1729 	if (mp->mnt_flag & MNT_EXPORTED) {
1730 		/*
1731 		 * Lookup in the export list first.
1732 		 */
1733 		if (nam != NULL) {
1734 			saddr = nam;
1735 			rnh = nep->ne_rtable[saddr->sa_family];
1736 			if (rnh != NULL) {
1737 				np = (struct netcred *)
1738 					(*rnh->rnh_matchaddr)((char *)saddr,
1739 							      rnh);
1740 				if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
1741 					np = NULL;
1742 			}
1743 		}
1744 		/*
1745 		 * If no address match, use the default if it exists.
1746 		 */
1747 		if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
1748 			np = &nep->ne_defexported;
1749 	}
1750 	return (np);
1751 }
1752 
1753 /*
1754  * perform msync on all vnodes under a mount point.  The mount point must
1755  * be locked.  This code is also responsible for lazy-freeing unreferenced
1756  * vnodes whos VM objects no longer contain pages.
1757  *
1758  * NOTE: MNT_WAIT still skips vnodes in the VXLOCK state.
1759  *
1760  * NOTE: XXX VOP_PUTPAGES and friends requires that the vnode be locked,
1761  * but vnode_pager_putpages() doesn't lock the vnode.  We have to do it
1762  * way up in this high level function.
1763  */
1764 static int vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data);
1765 static int vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data);
1766 
1767 void
1768 vfs_msync(struct mount *mp, int flags)
1769 {
1770 	int vmsc_flags;
1771 
1772 	vmsc_flags = VMSC_GETVP;
1773 	if (flags != MNT_WAIT)
1774 		vmsc_flags |= VMSC_NOWAIT;
1775 	vmntvnodescan(mp, vmsc_flags, vfs_msync_scan1, vfs_msync_scan2,
1776 			(void *)flags);
1777 }
1778 
1779 /*
1780  * scan1 is a fast pre-check.  There could be hundreds of thousands of
1781  * vnodes, we cannot afford to do anything heavy weight until we have a
1782  * fairly good indication that there is work to do.
1783  */
1784 static
1785 int
1786 vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data)
1787 {
1788 	int flags = (int)data;
1789 
1790 	if ((vp->v_flag & VRECLAIMED) == 0) {
1791 		if (vshouldfree(vp, 0))
1792 			return(0);	/* call scan2 */
1793 		if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
1794 		    (vp->v_flag & VOBJDIRTY) &&
1795 		    (flags == MNT_WAIT || VOP_ISLOCKED(vp, NULL) == 0)) {
1796 			return(0);	/* call scan2 */
1797 		}
1798 	}
1799 
1800 	/*
1801 	 * do not call scan2, continue the loop
1802 	 */
1803 	return(-1);
1804 }
1805 
1806 /*
1807  * This callback is handed a locked vnode.
1808  */
1809 static
1810 int
1811 vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data)
1812 {
1813 	vm_object_t obj;
1814 	int flags = (int)data;
1815 
1816 	if (vp->v_flag & VRECLAIMED)
1817 		return(0);
1818 
1819 	if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
1820 	    (vp->v_flag & VOBJDIRTY)) {
1821 		if (VOP_GETVOBJECT(vp, &obj) == 0) {
1822 			vm_object_page_clean(obj, 0, 0,
1823 			 flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
1824 		}
1825 	}
1826 	return(0);
1827 }
1828 
1829 /*
1830  * Create the VM object needed for VMIO and mmap support.  This
1831  * is done for all VREG files in the system.  Some filesystems might
1832  * afford the additional metadata buffering capability of the
1833  * VMIO code by making the device node be VMIO mode also.
1834  *
1835  * vp must be locked when vfs_object_create is called.
1836  */
1837 int
1838 vfs_object_create(struct vnode *vp, struct thread *td)
1839 {
1840 	return (VOP_CREATEVOBJECT(vp, td));
1841 }
1842 
1843 /*
1844  * Record a process's interest in events which might happen to
1845  * a vnode.  Because poll uses the historic select-style interface
1846  * internally, this routine serves as both the ``check for any
1847  * pending events'' and the ``record my interest in future events''
1848  * functions.  (These are done together, while the lock is held,
1849  * to avoid race conditions.)
1850  */
1851 int
1852 vn_pollrecord(struct vnode *vp, struct thread *td, int events)
1853 {
1854 	lwkt_tokref ilock;
1855 
1856 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
1857 	if (vp->v_pollinfo.vpi_revents & events) {
1858 		/*
1859 		 * This leaves events we are not interested
1860 		 * in available for the other process which
1861 		 * which presumably had requested them
1862 		 * (otherwise they would never have been
1863 		 * recorded).
1864 		 */
1865 		events &= vp->v_pollinfo.vpi_revents;
1866 		vp->v_pollinfo.vpi_revents &= ~events;
1867 
1868 		lwkt_reltoken(&ilock);
1869 		return events;
1870 	}
1871 	vp->v_pollinfo.vpi_events |= events;
1872 	selrecord(td, &vp->v_pollinfo.vpi_selinfo);
1873 	lwkt_reltoken(&ilock);
1874 	return 0;
1875 }
1876 
1877 /*
1878  * Note the occurrence of an event.  If the VN_POLLEVENT macro is used,
1879  * it is possible for us to miss an event due to race conditions, but
1880  * that condition is expected to be rare, so for the moment it is the
1881  * preferred interface.
1882  */
1883 void
1884 vn_pollevent(struct vnode *vp, int events)
1885 {
1886 	lwkt_tokref ilock;
1887 
1888 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
1889 	if (vp->v_pollinfo.vpi_events & events) {
1890 		/*
1891 		 * We clear vpi_events so that we don't
1892 		 * call selwakeup() twice if two events are
1893 		 * posted before the polling process(es) is
1894 		 * awakened.  This also ensures that we take at
1895 		 * most one selwakeup() if the polling process
1896 		 * is no longer interested.  However, it does
1897 		 * mean that only one event can be noticed at
1898 		 * a time.  (Perhaps we should only clear those
1899 		 * event bits which we note?) XXX
1900 		 */
1901 		vp->v_pollinfo.vpi_events = 0;	/* &= ~events ??? */
1902 		vp->v_pollinfo.vpi_revents |= events;
1903 		selwakeup(&vp->v_pollinfo.vpi_selinfo);
1904 	}
1905 	lwkt_reltoken(&ilock);
1906 }
1907 
1908 /*
1909  * Wake up anyone polling on vp because it is being revoked.
1910  * This depends on dead_poll() returning POLLHUP for correct
1911  * behavior.
1912  */
1913 void
1914 vn_pollgone(struct vnode *vp)
1915 {
1916 	lwkt_tokref ilock;
1917 
1918 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
1919 	if (vp->v_pollinfo.vpi_events) {
1920 		vp->v_pollinfo.vpi_events = 0;
1921 		selwakeup(&vp->v_pollinfo.vpi_selinfo);
1922 	}
1923 	lwkt_reltoken(&ilock);
1924 }
1925 
1926 /*
1927  * extract the dev_t from a VBLK or VCHR.  The vnode must have been opened
1928  * (or v_rdev might be NULL).
1929  */
1930 dev_t
1931 vn_todev(struct vnode *vp)
1932 {
1933 	if (vp->v_type != VBLK && vp->v_type != VCHR)
1934 		return (NODEV);
1935 	KKASSERT(vp->v_rdev != NULL);
1936 	return (vp->v_rdev);
1937 }
1938 
1939 /*
1940  * Check if vnode represents a disk device.  The vnode does not need to be
1941  * opened.
1942  */
1943 int
1944 vn_isdisk(struct vnode *vp, int *errp)
1945 {
1946 	dev_t dev;
1947 
1948 	if (vp->v_type != VBLK && vp->v_type != VCHR) {
1949 		if (errp != NULL)
1950 			*errp = ENOTBLK;
1951 		return (0);
1952 	}
1953 
1954 	if ((dev = vp->v_rdev) == NULL)
1955 		dev = udev2dev(vp->v_udev, (vp->v_type == VBLK));
1956 	if (dev == NULL || dev == NODEV) {
1957 		if (errp != NULL)
1958 			*errp = ENXIO;
1959 		return (0);
1960 	}
1961 	if (dev_is_good(dev) == 0) {
1962 		if (errp != NULL)
1963 			*errp = ENXIO;
1964 		return (0);
1965 	}
1966 	if ((dev_dflags(dev) & D_DISK) == 0) {
1967 		if (errp != NULL)
1968 			*errp = ENOTBLK;
1969 		return (0);
1970 	}
1971 	if (errp != NULL)
1972 		*errp = 0;
1973 	return (1);
1974 }
1975 
1976 #ifdef DEBUG_VFS_LOCKS
1977 
1978 void
1979 assert_vop_locked(struct vnode *vp, const char *str)
1980 {
1981 	if (vp && IS_LOCKING_VFS(vp) && !VOP_ISLOCKED(vp, NULL)) {
1982 		panic("%s: %p is not locked shared but should be", str, vp);
1983 	}
1984 }
1985 
1986 void
1987 assert_vop_unlocked(struct vnode *vp, const char *str)
1988 {
1989 	if (vp && IS_LOCKING_VFS(vp)) {
1990 		if (VOP_ISLOCKED(vp, curthread) == LK_EXCLUSIVE) {
1991 			panic("%s: %p is locked but should not be", str, vp);
1992 		}
1993 	}
1994 }
1995 
1996 #endif
1997 
1998 int
1999 vn_get_namelen(struct vnode *vp, int *namelen)
2000 {
2001 	int error, retval[2];
2002 
2003 	error = VOP_PATHCONF(vp, _PC_NAME_MAX, retval);
2004 	if (error)
2005 		return (error);
2006 	*namelen = *retval;
2007 	return (0);
2008 }
2009 
2010 int
2011 vop_write_dirent(int *error, struct uio *uio, ino_t d_ino, uint8_t d_type,
2012 		uint16_t d_namlen, const char *d_name)
2013 {
2014 	struct dirent *dp;
2015 	size_t len;
2016 
2017 	len = _DIRENT_RECLEN(d_namlen);
2018 	if (len > uio->uio_resid)
2019 		return(1);
2020 
2021 	dp = malloc(len, M_TEMP, M_WAITOK | M_ZERO);
2022 
2023 	dp->d_ino = d_ino;
2024 	dp->d_namlen = d_namlen;
2025 	dp->d_type = d_type;
2026 	bcopy(d_name, dp->d_name, d_namlen);
2027 
2028 	*error = uiomove((caddr_t)dp, len, uio);
2029 
2030 	free(dp, M_TEMP);
2031 
2032 	return(0);
2033 }
2034