xref: /dflybsd-src/sys/kern/vfs_subr.c (revision 53e987cee557d989dbf172d8a3c2ade9ea6fc46f)
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 1.55 2005/04/19 17:54:42 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/vmmeter.h>
68 #include <sys/vnode.h>
69 
70 #include <machine/limits.h>
71 
72 #include <vm/vm.h>
73 #include <vm/vm_object.h>
74 #include <vm/vm_extern.h>
75 #include <vm/vm_kern.h>
76 #include <vm/pmap.h>
77 #include <vm/vm_map.h>
78 #include <vm/vm_page.h>
79 #include <vm/vm_pager.h>
80 #include <vm/vnode_pager.h>
81 #include <vm/vm_zone.h>
82 
83 #include <sys/buf2.h>
84 #include <sys/thread2.h>
85 
86 static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
87 
88 int numvnodes;
89 SYSCTL_INT(_debug, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0, "");
90 int vfs_fastdev = 1;
91 SYSCTL_INT(_vfs, OID_AUTO, fastdev, CTLFLAG_RW, &vfs_fastdev, 0, "");
92 
93 enum vtype iftovt_tab[16] = {
94 	VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
95 	VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
96 };
97 int vttoif_tab[9] = {
98 	0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
99 	S_IFSOCK, S_IFIFO, S_IFMT,
100 };
101 
102 static int reassignbufcalls;
103 SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW,
104 		&reassignbufcalls, 0, "");
105 static int reassignbufloops;
106 SYSCTL_INT(_vfs, OID_AUTO, reassignbufloops, CTLFLAG_RW,
107 		&reassignbufloops, 0, "");
108 static int reassignbufsortgood;
109 SYSCTL_INT(_vfs, OID_AUTO, reassignbufsortgood, CTLFLAG_RW,
110 		&reassignbufsortgood, 0, "");
111 static int reassignbufsortbad;
112 SYSCTL_INT(_vfs, OID_AUTO, reassignbufsortbad, CTLFLAG_RW,
113 		&reassignbufsortbad, 0, "");
114 static int reassignbufmethod = 1;
115 SYSCTL_INT(_vfs, OID_AUTO, reassignbufmethod, CTLFLAG_RW,
116 		&reassignbufmethod, 0, "");
117 
118 int	nfs_mount_type = -1;
119 static struct lwkt_token spechash_token;
120 struct nfs_public nfs_pub;	/* publicly exported FS */
121 
122 int desiredvnodes;
123 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
124 		&desiredvnodes, 0, "Maximum number of vnodes");
125 
126 static void	vfs_free_addrlist (struct netexport *nep);
127 static int	vfs_free_netcred (struct radix_node *rn, void *w);
128 static int	vfs_hang_addrlist (struct mount *mp, struct netexport *nep,
129 				       struct export_args *argp);
130 
131 extern int dev_ref_debug;
132 extern struct vnodeopv_entry_desc spec_vnodeop_entries[];
133 
134 /*
135  * Red black tree functions
136  */
137 static int rb_buf_compare(struct buf *b1, struct buf *b2);
138 RB_GENERATE(buf_rb_tree, buf, b_rbnode, rb_buf_compare);
139 
140 static int
141 rb_buf_compare(struct buf *b1, struct buf *b2)
142 {
143 	if (b1->b_lblkno < b2->b_lblkno)
144 		return(-1);
145 	if (b1->b_lblkno > b2->b_lblkno)
146 		return(1);
147 	return(0);
148 }
149 
150 /*
151  * Return 0 if the vnode is already on the free list or cannot be placed
152  * on the free list.  Return 1 if the vnode can be placed on the free list.
153  */
154 static __inline int
155 vshouldfree(struct vnode *vp, int usecount)
156 {
157 	if (vp->v_flag & VFREE)
158 		return (0);		/* already free */
159 	if (vp->v_holdcnt != 0 || vp->v_usecount != usecount)
160 		return (0);		/* other holderse */
161 	if (vp->v_object &&
162 	    (vp->v_object->ref_count || vp->v_object->resident_page_count)) {
163 		return (0);
164 	}
165 	return (1);
166 }
167 
168 /*
169  * Initialize the vnode management data structures.
170  *
171  * Called from vfsinit()
172  */
173 void
174 vfs_subr_init(void)
175 {
176 	/*
177 	 * Desired vnodes is a result of the physical page count
178 	 * and the size of kernel's heap.  It scales in proportion
179 	 * to the amount of available physical memory.  This can
180 	 * cause trouble on 64-bit and large memory platforms.
181 	 */
182 	/* desiredvnodes = maxproc + vmstats.v_page_count / 4; */
183 	desiredvnodes =
184 		min(maxproc + vmstats.v_page_count /4,
185 		    2 * (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) /
186 		    (5 * (sizeof(struct vm_object) + sizeof(struct vnode))));
187 
188 	lwkt_token_init(&spechash_token);
189 }
190 
191 /*
192  * Knob to control the precision of file timestamps:
193  *
194  *   0 = seconds only; nanoseconds zeroed.
195  *   1 = seconds and nanoseconds, accurate within 1/HZ.
196  *   2 = seconds and nanoseconds, truncated to microseconds.
197  * >=3 = seconds and nanoseconds, maximum precision.
198  */
199 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
200 
201 static int timestamp_precision = TSP_SEC;
202 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
203 		&timestamp_precision, 0, "");
204 
205 /*
206  * Get a current timestamp.
207  */
208 void
209 vfs_timestamp(struct timespec *tsp)
210 {
211 	struct timeval tv;
212 
213 	switch (timestamp_precision) {
214 	case TSP_SEC:
215 		tsp->tv_sec = time_second;
216 		tsp->tv_nsec = 0;
217 		break;
218 	case TSP_HZ:
219 		getnanotime(tsp);
220 		break;
221 	case TSP_USEC:
222 		microtime(&tv);
223 		TIMEVAL_TO_TIMESPEC(&tv, tsp);
224 		break;
225 	case TSP_NSEC:
226 	default:
227 		nanotime(tsp);
228 		break;
229 	}
230 }
231 
232 /*
233  * Set vnode attributes to VNOVAL
234  */
235 void
236 vattr_null(struct vattr *vap)
237 {
238 	vap->va_type = VNON;
239 	vap->va_size = VNOVAL;
240 	vap->va_bytes = VNOVAL;
241 	vap->va_mode = VNOVAL;
242 	vap->va_nlink = VNOVAL;
243 	vap->va_uid = VNOVAL;
244 	vap->va_gid = VNOVAL;
245 	vap->va_fsid = VNOVAL;
246 	vap->va_fileid = VNOVAL;
247 	vap->va_blocksize = VNOVAL;
248 	vap->va_rdev = VNOVAL;
249 	vap->va_atime.tv_sec = VNOVAL;
250 	vap->va_atime.tv_nsec = VNOVAL;
251 	vap->va_mtime.tv_sec = VNOVAL;
252 	vap->va_mtime.tv_nsec = VNOVAL;
253 	vap->va_ctime.tv_sec = VNOVAL;
254 	vap->va_ctime.tv_nsec = VNOVAL;
255 	vap->va_flags = VNOVAL;
256 	vap->va_gen = VNOVAL;
257 	vap->va_vaflags = 0;
258 }
259 
260 /*
261  * Update outstanding I/O count and do wakeup if requested.
262  */
263 void
264 vwakeup(struct buf *bp)
265 {
266 	struct vnode *vp;
267 
268 	if ((vp = bp->b_vp)) {
269 		vp->v_numoutput--;
270 		if (vp->v_numoutput < 0)
271 			panic("vwakeup: neg numoutput");
272 		if ((vp->v_numoutput == 0) && (vp->v_flag & VBWAIT)) {
273 			vp->v_flag &= ~VBWAIT;
274 			wakeup((caddr_t) &vp->v_numoutput);
275 		}
276 	}
277 }
278 
279 /*
280  * Flush out and invalidate all buffers associated with a vnode.
281  *
282  * vp must be locked.
283  */
284 static int vinvalbuf_bp(struct buf *bp, void *data);
285 
286 struct vinvalbuf_bp_info {
287 	struct vnode *vp;
288 	int slptimeo;
289 	int slpflag;
290 	int flags;
291 };
292 
293 int
294 vinvalbuf(struct vnode *vp, int flags, struct thread *td,
295 	int slpflag, int slptimeo)
296 {
297 	struct vinvalbuf_bp_info info;
298 	int s, error;
299 	vm_object_t object;
300 
301 	/*
302 	 * If we are being asked to save, call fsync to ensure that the inode
303 	 * is updated.
304 	 */
305 	if (flags & V_SAVE) {
306 		s = splbio();
307 		while (vp->v_numoutput) {
308 			vp->v_flag |= VBWAIT;
309 			error = tsleep((caddr_t)&vp->v_numoutput,
310 			    slpflag, "vinvlbuf", slptimeo);
311 			if (error) {
312 				splx(s);
313 				return (error);
314 			}
315 		}
316 		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
317 			splx(s);
318 			if ((error = VOP_FSYNC(vp, MNT_WAIT, td)) != 0)
319 				return (error);
320 			s = splbio();
321 			if (vp->v_numoutput > 0 ||
322 			    !RB_EMPTY(&vp->v_rbdirty_tree))
323 				panic("vinvalbuf: dirty bufs");
324 		}
325 		splx(s);
326   	}
327 	s = splbio();
328 	info.slptimeo = slptimeo;
329 	info.slpflag = slpflag;
330 	info.flags = flags;
331 	info.vp = vp;
332 
333 	/*
334 	 * Flush the buffer cache until nothing is left.
335 	 */
336 	while (!RB_EMPTY(&vp->v_rbclean_tree) ||
337 	    !RB_EMPTY(&vp->v_rbdirty_tree)) {
338 		error = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree, NULL,
339 			vinvalbuf_bp, &info);
340 		if (error == 0) {
341 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
342 					vinvalbuf_bp, &info);
343 		}
344 	}
345 
346 	/*
347 	 * Wait for I/O to complete.  XXX needs cleaning up.  The vnode can
348 	 * have write I/O in-progress but if there is a VM object then the
349 	 * VM object can also have read-I/O in-progress.
350 	 */
351 	do {
352 		while (vp->v_numoutput > 0) {
353 			vp->v_flag |= VBWAIT;
354 			tsleep(&vp->v_numoutput, 0, "vnvlbv", 0);
355 		}
356 		if (VOP_GETVOBJECT(vp, &object) == 0) {
357 			while (object->paging_in_progress)
358 				vm_object_pip_sleep(object, "vnvlbx");
359 		}
360 	} while (vp->v_numoutput > 0);
361 
362 	splx(s);
363 
364 	/*
365 	 * Destroy the copy in the VM cache, too.
366 	 */
367 	if (VOP_GETVOBJECT(vp, &object) == 0) {
368 		vm_object_page_remove(object, 0, 0,
369 			(flags & V_SAVE) ? TRUE : FALSE);
370 	}
371 
372 	if (!RB_EMPTY(&vp->v_rbdirty_tree) || !RB_EMPTY(&vp->v_rbclean_tree))
373 		panic("vinvalbuf: flush failed");
374 	return (0);
375 }
376 
377 static int
378 vinvalbuf_bp(struct buf *bp, void *data)
379 {
380 	struct vinvalbuf_bp_info *info = data;
381 	int error;
382 
383 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
384 		error = BUF_TIMELOCK(bp,
385 		    LK_EXCLUSIVE | LK_SLEEPFAIL,
386 		    "vinvalbuf", info->slpflag, info->slptimeo);
387 		if (error == 0) {
388 			BUF_UNLOCK(bp);
389 			error = ENOLCK;
390 		}
391 		if (error == ENOLCK)
392 			return(0);
393 		return (-error);
394 	}
395 	/*
396 	 * XXX Since there are no node locks for NFS, I
397 	 * believe there is a slight chance that a delayed
398 	 * write will occur while sleeping just above, so
399 	 * check for it.  Note that vfs_bio_awrite expects
400 	 * buffers to reside on a queue, while VOP_BWRITE and
401 	 * brelse do not.
402 	 */
403 	if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
404 	    (info->flags & V_SAVE)) {
405 		if (bp->b_vp == info->vp) {
406 			if (bp->b_flags & B_CLUSTEROK) {
407 				BUF_UNLOCK(bp);
408 				vfs_bio_awrite(bp);
409 			} else {
410 				bremfree(bp);
411 				bp->b_flags |= B_ASYNC;
412 				VOP_BWRITE(bp->b_vp, bp);
413 			}
414 		} else {
415 			bremfree(bp);
416 			VOP_BWRITE(bp->b_vp, bp);
417 		}
418 	} else {
419 		bremfree(bp);
420 		bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
421 		bp->b_flags &= ~B_ASYNC;
422 		brelse(bp);
423 	}
424 	return(0);
425 }
426 
427 /*
428  * Truncate a file's buffer and pages to a specified length.  This
429  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
430  * sync activity.
431  *
432  * The vnode must be locked.
433  */
434 static int vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data);
435 static int vtruncbuf_bp_trunc(struct buf *bp, void *data);
436 static int vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data);
437 static int vtruncbuf_bp_metasync(struct buf *bp, void *data);
438 
439 int
440 vtruncbuf(struct vnode *vp, struct thread *td, off_t length, int blksize)
441 {
442 	daddr_t trunclbn;
443 	int count;
444 	int s;
445 
446 	/*
447 	 * Round up to the *next* lbn, then destroy the buffers in question.
448 	 * Since we are only removing some of the buffers we must rely on the
449 	 * scan count to determine whether a loop is necessary.
450 	 */
451 	trunclbn = (length + blksize - 1) / blksize;
452 
453 	s = splbio();
454 	do {
455 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
456 				vtruncbuf_bp_trunc_cmp,
457 				vtruncbuf_bp_trunc, &trunclbn);
458 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
459 				vtruncbuf_bp_trunc_cmp,
460 				vtruncbuf_bp_trunc, &trunclbn);
461 	} while(count);
462 
463 	/*
464 	 * For safety, fsync any remaining metadata if the file is not being
465 	 * truncated to 0.  Since the metadata does not represent the entire
466 	 * dirty list we have to rely on the hit count to ensure that we get
467 	 * all of it.
468 	 */
469 	if (length > 0) {
470 		do {
471 			count = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
472 					vtruncbuf_bp_metasync_cmp,
473 					vtruncbuf_bp_metasync, vp);
474 		} while (count);
475 	}
476 
477 	/*
478 	 * Wait for any in-progress I/O to complete before returning (why?)
479 	 */
480 	while (vp->v_numoutput > 0) {
481 		vp->v_flag |= VBWAIT;
482 		tsleep(&vp->v_numoutput, 0, "vbtrunc", 0);
483 	}
484 
485 	splx(s);
486 
487 	vnode_pager_setsize(vp, length);
488 
489 	return (0);
490 }
491 
492 /*
493  * The callback buffer is beyond the new file EOF and must be destroyed.
494  * Note that the compare function must conform to the RB_SCAN's requirements.
495  */
496 static
497 int
498 vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data)
499 {
500 	if (bp->b_lblkno >= *(daddr_t *)data)
501 		return(0);
502 	return(-1);
503 }
504 
505 static
506 int
507 vtruncbuf_bp_trunc(struct buf *bp, void *data)
508 {
509 	/*
510 	 * Do not try to use a buffer we cannot immediately lock, but sleep
511 	 * anyway to prevent a livelock.  The code will loop until all buffers
512 	 * can be acted upon.
513 	 */
514 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
515 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
516 			BUF_UNLOCK(bp);
517 	} else {
518 		bremfree(bp);
519 		bp->b_flags |= (B_INVAL | B_RELBUF);
520 		bp->b_flags &= ~B_ASYNC;
521 		brelse(bp);
522 	}
523 	return(1);
524 }
525 
526 /*
527  * Fsync all meta-data after truncating a file to be non-zero.  Only metadata
528  * blocks (with a negative lblkno) are scanned.
529  * Note that the compare function must conform to the RB_SCAN's requirements.
530  */
531 static int
532 vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data)
533 {
534 	if (bp->b_lblkno < 0)
535 		return(0);
536 	return(1);
537 }
538 
539 static int
540 vtruncbuf_bp_metasync(struct buf *bp, void *data)
541 {
542 	struct vnode *vp = data;
543 
544 	if (bp->b_flags & B_DELWRI) {
545 		/*
546 		 * Do not try to use a buffer we cannot immediately lock,
547 		 * but sleep anyway to prevent a livelock.  The code will
548 		 * loop until all buffers can be acted upon.
549 		 */
550 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
551 			if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
552 				BUF_UNLOCK(bp);
553 		} else {
554 			bremfree(bp);
555 			if (bp->b_vp == vp) {
556 				bp->b_flags |= B_ASYNC;
557 			} else {
558 				bp->b_flags &= ~B_ASYNC;
559 			}
560 			VOP_BWRITE(bp->b_vp, bp);
561 		}
562 		return(1);
563 	} else {
564 		return(0);
565 	}
566 }
567 
568 /*
569  * vfsync - implements a multipass fsync on a file which understands
570  * dependancies and meta-data.  The passed vnode must be locked.  The
571  * waitfor argument may be MNT_WAIT or MNT_NOWAIT, or MNT_LAZY.
572  *
573  * When fsyncing data asynchronously just do one consolidated pass starting
574  * with the most negative block number.  This may not get all the data due
575  * to dependancies.
576  *
577  * When fsyncing data synchronously do a data pass, then a metadata pass,
578  * then do additional data+metadata passes to try to get all the data out.
579  */
580 static int vfsync_wait_output(struct vnode *vp,
581 			    int (*waitoutput)(struct vnode *, struct thread *));
582 static int vfsync_data_only_cmp(struct buf *bp, void *data);
583 static int vfsync_meta_only_cmp(struct buf *bp, void *data);
584 static int vfsync_lazy_range_cmp(struct buf *bp, void *data);
585 static int vfsync_bp(struct buf *bp, void *data);
586 
587 struct vfsync_info {
588 	struct vnode *vp;
589 	int synchronous;
590 	int syncdeps;
591 	int lazycount;
592 	int lazylimit;
593 	daddr_t lbn;
594 	int s;
595 	int (*checkdef)(struct buf *);
596 };
597 
598 int
599 vfsync(struct vnode *vp, int waitfor, int passes, daddr_t lbn,
600 	int (*checkdef)(struct buf *),
601 	int (*waitoutput)(struct vnode *, struct thread *))
602 {
603 	struct vfsync_info info;
604 	int error;
605 
606 	bzero(&info, sizeof(info));
607 	info.vp = vp;
608 	info.s = splbio();
609 	info.lbn = lbn;
610 	if ((info.checkdef = checkdef) == NULL)
611 		info.syncdeps = 1;
612 
613 	switch(waitfor) {
614 	case MNT_LAZY:
615 		/*
616 		 * Lazy (filesystem syncer typ) Asynchronous plus limit the
617 		 * number of data (not meta) pages we try to flush to 1MB.
618 		 * A non-zero return means that lazy limit was reached.
619 		 */
620 		info.lazylimit = 1024 * 1024;
621 		info.syncdeps = 1;
622 		error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
623 				vfsync_lazy_range_cmp, vfsync_bp, &info);
624 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
625 				vfsync_meta_only_cmp, vfsync_bp, &info);
626 		if (error == 0)
627 			vp->v_lazyw = 0;
628 		else if (!RB_EMPTY(&vp->v_rbdirty_tree))
629 			vn_syncer_add_to_worklist(vp, 1);
630 		error = 0;
631 		break;
632 	case MNT_NOWAIT:
633 		/*
634 		 * Asynchronous.  Do a data-only pass and a meta-only pass.
635 		 */
636 		info.syncdeps = 1;
637 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
638 			vfsync_bp, &info);
639 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_meta_only_cmp,
640 			vfsync_bp, &info);
641 		error = 0;
642 		break;
643 	default:
644 		/*
645 		 * Synchronous.  Do a data-only pass, then a meta-data+data
646 		 * pass, then additional integrated passes to try to get
647 		 * all the dependancies flushed.
648 		 */
649 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
650 			vfsync_bp, &info);
651 		error = vfsync_wait_output(vp, waitoutput);
652 		if (error == 0) {
653 			RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
654 				vfsync_bp, &info);
655 			error = vfsync_wait_output(vp, waitoutput);
656 		}
657 		while (error == 0 && passes > 0 &&
658 		    !RB_EMPTY(&vp->v_rbdirty_tree)) {
659 			if (--passes == 0) {
660 				info.synchronous = 1;
661 				info.syncdeps = 1;
662 			}
663 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
664 				vfsync_bp, &info);
665 			if (error < 0)
666 				error = -error;
667 			info.syncdeps = 1;
668 			if (error == 0)
669 				error = vfsync_wait_output(vp, waitoutput);
670 		}
671 		break;
672 	}
673 	splx(info.s);
674 	return(error);
675 }
676 
677 static int
678 vfsync_wait_output(struct vnode *vp, int (*waitoutput)(struct vnode *, struct thread *))
679 {
680 	int error = 0;
681 
682 	while (vp->v_numoutput) {
683 		vp->v_flag |= VBWAIT;
684 		tsleep(&vp->v_numoutput, 0, "fsfsn", 0);
685 	}
686 	if (waitoutput)
687 		error = waitoutput(vp, curthread);
688 	return(error);
689 }
690 
691 static int
692 vfsync_data_only_cmp(struct buf *bp, void *data)
693 {
694 	if (bp->b_lblkno < 0)
695 		return(-1);
696 	return(0);
697 }
698 
699 static int
700 vfsync_meta_only_cmp(struct buf *bp, void *data)
701 {
702 	if (bp->b_lblkno < 0)
703 		return(0);
704 	return(1);
705 }
706 
707 static int
708 vfsync_lazy_range_cmp(struct buf *bp, void *data)
709 {
710 	struct vfsync_info *info = data;
711 	if (bp->b_lblkno < info->vp->v_lazyw)
712 		return(-1);
713 	return(0);
714 }
715 
716 static int
717 vfsync_bp(struct buf *bp, void *data)
718 {
719 	struct vfsync_info *info = data;
720 	struct vnode *vp = info->vp;
721 	int error;
722 
723 	/*
724 	 * if syncdeps is not set we do not try to write buffers which have
725 	 * dependancies.
726 	 */
727 	if (!info->synchronous && info->syncdeps == 0 && info->checkdef(bp))
728 		return(0);
729 
730 	/*
731 	 * Ignore buffers that we cannot immediately lock.  XXX
732 	 */
733 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT))
734 		return(0);
735 	if ((bp->b_flags & B_DELWRI) == 0)
736 		panic("vfsync_bp: buffer not dirty");
737 	if (vp != bp->b_vp)
738 		panic("vfsync_bp: buffer vp mismatch");
739 
740 	/*
741 	 * B_NEEDCOMMIT (primarily used by NFS) is a state where the buffer
742 	 * has been written but an additional handshake with the device
743 	 * is required before we can dispose of the buffer.  We have no idea
744 	 * how to do this so we have to skip these buffers.
745 	 */
746 	if (bp->b_flags & B_NEEDCOMMIT) {
747 		BUF_UNLOCK(bp);
748 		return(0);
749 	}
750 
751 	/*
752 	 * (LEGACY FROM UFS, REMOVE WHEN POSSIBLE) - invalidate any dirty
753 	 * buffers beyond the file EOF.
754 	 */
755 	if (info->lbn != (daddr_t)-1 && vp->v_type == VREG &&
756 	    bp->b_lblkno >= info->lbn) {
757 		bremfree(bp);
758 		bp->b_flags |= B_INVAL | B_NOCACHE;
759 		splx(info->s);
760 		brelse(bp);
761 		info->s = splbio();
762 	}
763 
764 	if (info->synchronous) {
765 		/*
766 		 * Synchronous flushing.  An error may be returned.
767 		 */
768 		bremfree(bp);
769 		splx(info->s);
770 		error = bwrite(bp);
771 		info->s = splbio();
772 	} else {
773 		/*
774 		 * Asynchronous flushing.  A negative return value simply
775 		 * stops the scan and is not considered an error.  We use
776 		 * this to support limited MNT_LAZY flushes.
777 		 */
778 		vp->v_lazyw = bp->b_lblkno;
779 		if ((vp->v_flag & VOBJBUF) && (bp->b_flags & B_CLUSTEROK)) {
780 			BUF_UNLOCK(bp);
781 			info->lazycount += vfs_bio_awrite(bp);
782 		} else {
783 			info->lazycount += bp->b_bufsize;
784 			bremfree(bp);
785 			splx(info->s);
786 			bawrite(bp);
787 			info->s = splbio();
788 		}
789 		if (info->lazylimit && info->lazycount >= info->lazylimit)
790 			error = 1;
791 		else
792 			error = 0;
793 	}
794 	return(-error);
795 }
796 
797 /*
798  * Associate a buffer with a vnode.
799  */
800 void
801 bgetvp(struct vnode *vp, struct buf *bp)
802 {
803 	KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));
804 
805 	vhold(vp);
806 	bp->b_vp = vp;
807 	bp->b_dev = vn_todev(vp);
808 	/*
809 	 * Insert onto list for new vnode.
810 	 */
811 	crit_enter();
812 	bp->b_xflags |= BX_VNCLEAN;
813 	bp->b_xflags &= ~BX_VNDIRTY;
814 	if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp))
815 		panic("reassignbuf: dup lblk vp %p bp %p", vp, bp);
816 	crit_exit();
817 }
818 
819 /*
820  * Disassociate a buffer from a vnode.
821  */
822 void
823 brelvp(struct buf *bp)
824 {
825 	struct vnode *vp;
826 
827 	KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
828 
829 	/*
830 	 * Delete from old vnode list, if on one.
831 	 */
832 	vp = bp->b_vp;
833 	crit_enter();
834 	if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) {
835 		if (bp->b_xflags & BX_VNDIRTY)
836 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
837 		else
838 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
839 		bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
840 	}
841 	if ((vp->v_flag & VONWORKLST) && RB_EMPTY(&vp->v_rbdirty_tree)) {
842 		vp->v_flag &= ~VONWORKLST;
843 		LIST_REMOVE(vp, v_synclist);
844 	}
845 	crit_exit();
846 	bp->b_vp = NULL;
847 	vdrop(vp);
848 }
849 
850 /*
851  * Associate a p-buffer with a vnode.
852  *
853  * Also sets B_PAGING flag to indicate that vnode is not fully associated
854  * with the buffer.  i.e. the bp has not been linked into the vnode or
855  * ref-counted.
856  */
857 void
858 pbgetvp(struct vnode *vp, struct buf *bp)
859 {
860 	KASSERT(bp->b_vp == NULL, ("pbgetvp: not free"));
861 
862 	bp->b_vp = vp;
863 	bp->b_flags |= B_PAGING;
864 	bp->b_dev = vn_todev(vp);
865 }
866 
867 /*
868  * Disassociate a p-buffer from a vnode.
869  */
870 void
871 pbrelvp(struct buf *bp)
872 {
873 	KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL"));
874 
875 	bp->b_vp = NULL;
876 	bp->b_flags &= ~B_PAGING;
877 }
878 
879 void
880 pbreassignbuf(struct buf *bp, struct vnode *newvp)
881 {
882 	if ((bp->b_flags & B_PAGING) == 0) {
883 		panic(
884 		    "pbreassignbuf() on non phys bp %p",
885 		    bp
886 		);
887 	}
888 	bp->b_vp = newvp;
889 }
890 
891 /*
892  * Reassign a buffer from one vnode to another.
893  * Used to assign file specific control information
894  * (indirect blocks) to the vnode to which they belong.
895  */
896 void
897 reassignbuf(struct buf *bp, struct vnode *newvp)
898 {
899 	int delay;
900 
901 	if (newvp == NULL) {
902 		printf("reassignbuf: NULL");
903 		return;
904 	}
905 	++reassignbufcalls;
906 
907 	/*
908 	 * B_PAGING flagged buffers cannot be reassigned because their vp
909 	 * is not fully linked in.
910 	 */
911 	if (bp->b_flags & B_PAGING)
912 		panic("cannot reassign paging buffer");
913 
914 	crit_enter();
915 	/*
916 	 * Delete from old vnode list, if on one.
917 	 */
918 	if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) {
919 		if (bp->b_xflags & BX_VNDIRTY)
920 			buf_rb_tree_RB_REMOVE(&bp->b_vp->v_rbdirty_tree, bp);
921 		else
922 			buf_rb_tree_RB_REMOVE(&bp->b_vp->v_rbclean_tree, bp);
923 		bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
924 		if (bp->b_vp != newvp) {
925 			vdrop(bp->b_vp);
926 			bp->b_vp = NULL;	/* for clarification */
927 		}
928 	}
929 	/*
930 	 * If dirty, put on list of dirty buffers; otherwise insert onto list
931 	 * of clean buffers.
932 	 */
933 	if (bp->b_flags & B_DELWRI) {
934 		if ((newvp->v_flag & VONWORKLST) == 0) {
935 			switch (newvp->v_type) {
936 			case VDIR:
937 				delay = dirdelay;
938 				break;
939 			case VCHR:
940 			case VBLK:
941 				if (newvp->v_rdev &&
942 				    newvp->v_rdev->si_mountpoint != NULL) {
943 					delay = metadelay;
944 					break;
945 				}
946 				/* fall through */
947 			default:
948 				delay = filedelay;
949 			}
950 			vn_syncer_add_to_worklist(newvp, delay);
951 		}
952 		bp->b_xflags |= BX_VNDIRTY;
953 		if (buf_rb_tree_RB_INSERT(&newvp->v_rbdirty_tree, bp))
954 			panic("reassignbuf: dup lblk vp %p bp %p", newvp, bp);
955 	} else {
956 		bp->b_xflags |= BX_VNCLEAN;
957 		if (buf_rb_tree_RB_INSERT(&newvp->v_rbclean_tree, bp))
958 			panic("reassignbuf: dup lblk vp %p bp %p", newvp, bp);
959 		if ((newvp->v_flag & VONWORKLST) &&
960 		    RB_EMPTY(&newvp->v_rbdirty_tree)) {
961 			newvp->v_flag &= ~VONWORKLST;
962 			LIST_REMOVE(newvp, v_synclist);
963 		}
964 	}
965 	if (bp->b_vp != newvp) {
966 		bp->b_vp = newvp;
967 		vhold(bp->b_vp);
968 	}
969 	crit_exit();
970 }
971 
972 /*
973  * Create a vnode for a block device.
974  * Used for mounting the root file system.
975  */
976 int
977 bdevvp(dev_t dev, struct vnode **vpp)
978 {
979 	struct vnode *vp;
980 	struct vnode *nvp;
981 	int error;
982 
983 	if (dev == NODEV) {
984 		*vpp = NULLVP;
985 		return (ENXIO);
986 	}
987 	error = getspecialvnode(VT_NON, NULL, &spec_vnode_vops, &nvp, 0, 0);
988 	if (error) {
989 		*vpp = NULLVP;
990 		return (error);
991 	}
992 	vp = nvp;
993 	vp->v_type = VCHR;
994 	vp->v_udev = dev->si_udev;
995 	vx_unlock(vp);
996 	*vpp = vp;
997 	return (0);
998 }
999 
1000 int
1001 v_associate_rdev(struct vnode *vp, dev_t dev)
1002 {
1003 	lwkt_tokref ilock;
1004 
1005 	if (dev == NULL || dev == NODEV)
1006 		return(ENXIO);
1007 	if (dev_is_good(dev) == 0)
1008 		return(ENXIO);
1009 	KKASSERT(vp->v_rdev == NULL);
1010 	if (dev_ref_debug)
1011 		printf("Z1");
1012 	vp->v_rdev = reference_dev(dev);
1013 	lwkt_gettoken(&ilock, &spechash_token);
1014 	SLIST_INSERT_HEAD(&dev->si_hlist, vp, v_specnext);
1015 	lwkt_reltoken(&ilock);
1016 	return(0);
1017 }
1018 
1019 void
1020 v_release_rdev(struct vnode *vp)
1021 {
1022 	lwkt_tokref ilock;
1023 	dev_t dev;
1024 
1025 	if ((dev = vp->v_rdev) != NULL) {
1026 		lwkt_gettoken(&ilock, &spechash_token);
1027 		SLIST_REMOVE(&dev->si_hlist, vp, vnode, v_specnext);
1028 		if (dev_ref_debug && vp->v_opencount != 0) {
1029 			printf("releasing rdev with non-0 "
1030 				"v_opencount(%d) (revoked?)\n",
1031 				vp->v_opencount);
1032 		}
1033 		vp->v_rdev = NULL;
1034 		vp->v_opencount = 0;
1035 		release_dev(dev);
1036 		lwkt_reltoken(&ilock);
1037 	}
1038 }
1039 
1040 /*
1041  * Add a vnode to the alias list hung off the dev_t.  We only associate
1042  * the device number with the vnode.  The actual device is not associated
1043  * until the vnode is opened (usually in spec_open()), and will be
1044  * disassociated on last close.
1045  */
1046 void
1047 addaliasu(struct vnode *nvp, udev_t nvp_udev)
1048 {
1049 	if (nvp->v_type != VBLK && nvp->v_type != VCHR)
1050 		panic("addaliasu on non-special vnode");
1051 	nvp->v_udev = nvp_udev;
1052 }
1053 
1054 /*
1055  * Disassociate a vnode from its underlying filesystem.
1056  *
1057  * The vnode must be VX locked and refd
1058  *
1059  * If there are v_usecount references to the vnode other then ours we have
1060  * to VOP_CLOSE the vnode before we can deactivate and reclaim it.
1061  */
1062 void
1063 vclean(struct vnode *vp, int flags, struct thread *td)
1064 {
1065 	int active;
1066 
1067 	/*
1068 	 * If the vnode has already been reclaimed we have nothing to do.
1069 	 */
1070 	if (vp->v_flag & VRECLAIMED)
1071 		return;
1072 	vp->v_flag |= VRECLAIMED;
1073 
1074 	/*
1075 	 * Scrap the vfs cache
1076 	 */
1077 	while (cache_inval_vp(vp, 0) != 0) {
1078 		printf("Warning: vnode %p clean/cache_resolution race detected\n", vp);
1079 		tsleep(vp, 0, "vclninv", 2);
1080 	}
1081 
1082 	/*
1083 	 * Check to see if the vnode is in use. If so we have to reference it
1084 	 * before we clean it out so that its count cannot fall to zero and
1085 	 * generate a race against ourselves to recycle it.
1086 	 */
1087 	active = (vp->v_usecount > 1);
1088 
1089 	/*
1090 	 * Clean out any buffers associated with the vnode and destroy its
1091 	 * object, if it has one.
1092 	 */
1093 	vinvalbuf(vp, V_SAVE, td, 0, 0);
1094 	VOP_DESTROYVOBJECT(vp);
1095 
1096 	/*
1097 	 * If purging an active vnode, it must be closed and
1098 	 * deactivated before being reclaimed.   XXX
1099 	 *
1100 	 * Note that neither of these routines unlocks the vnode.
1101 	 */
1102 	if (active) {
1103 		if (flags & DOCLOSE)
1104 			VOP_CLOSE(vp, FNONBLOCK, td);
1105 	}
1106 
1107 	/*
1108 	 * If the vnode has not be deactivated, deactivated it.
1109 	 */
1110 	if ((vp->v_flag & VINACTIVE) == 0) {
1111 		vp->v_flag |= VINACTIVE;
1112 		VOP_INACTIVE(vp, td);
1113 	}
1114 
1115 	/*
1116 	 * Reclaim the vnode.
1117 	 */
1118 	if (VOP_RECLAIM(vp, td))
1119 		panic("vclean: cannot reclaim");
1120 
1121 	/*
1122 	 * Done with purge, notify sleepers of the grim news.
1123 	 */
1124 	vp->v_ops = &dead_vnode_vops;
1125 	vn_pollgone(vp);
1126 	vp->v_tag = VT_NON;
1127 }
1128 
1129 /*
1130  * Eliminate all activity associated with the requested vnode
1131  * and with all vnodes aliased to the requested vnode.
1132  *
1133  * The vnode must be referenced and vx_lock()'d
1134  *
1135  * revoke { struct vnode *a_vp, int a_flags }
1136  */
1137 int
1138 vop_stdrevoke(struct vop_revoke_args *ap)
1139 {
1140 	struct vnode *vp, *vq;
1141 	lwkt_tokref ilock;
1142 	dev_t dev;
1143 
1144 	KASSERT((ap->a_flags & REVOKEALL) != 0, ("vop_revoke"));
1145 
1146 	vp = ap->a_vp;
1147 
1148 	/*
1149 	 * If the vnode is already dead don't try to revoke it
1150 	 */
1151 	if (vp->v_flag & VRECLAIMED)
1152 		return (0);
1153 
1154 	/*
1155 	 * If the vnode has a device association, scrap all vnodes associated
1156 	 * with the device.  Don't let the device disappear on us while we
1157 	 * are scrapping the vnodes.
1158 	 *
1159 	 * The passed vp will probably show up in the list, do not VX lock
1160 	 * it twice!
1161 	 */
1162 	if (vp->v_type != VCHR && vp->v_type != VBLK)
1163 		return(0);
1164 	if ((dev = vp->v_rdev) == NULL) {
1165 		if ((dev = udev2dev(vp->v_udev, vp->v_type == VBLK)) == NODEV)
1166 			return(0);
1167 	}
1168 	reference_dev(dev);
1169 	lwkt_gettoken(&ilock, &spechash_token);
1170 	while ((vq = SLIST_FIRST(&dev->si_hlist)) != NULL) {
1171 		if (vp == vq || vx_get(vq) == 0) {
1172 			if (vq == SLIST_FIRST(&dev->si_hlist))
1173 				vgone(vq);
1174 			if (vp != vq)
1175 				vx_put(vq);
1176 		}
1177 	}
1178 	lwkt_reltoken(&ilock);
1179 	release_dev(dev);
1180 	return (0);
1181 }
1182 
1183 /*
1184  * Recycle an unused vnode to the front of the free list.
1185  *
1186  * Returns 1 if we were successfully able to recycle the vnode,
1187  * 0 otherwise.
1188  */
1189 int
1190 vrecycle(struct vnode *vp, struct thread *td)
1191 {
1192 	if (vp->v_usecount == 1) {
1193 		vgone(vp);
1194 		return (1);
1195 	}
1196 	return (0);
1197 }
1198 
1199 /*
1200  * Eliminate all activity associated with a vnode in preparation for reuse.
1201  *
1202  * The vnode must be VX locked and refd and will remain VX locked and refd
1203  * on return.  This routine may be called with the vnode in any state, as
1204  * long as it is VX locked.  The vnode will be cleaned out and marked
1205  * VRECLAIMED but will not actually be reused until all existing refs and
1206  * holds go away.
1207  *
1208  * NOTE: This routine may be called on a vnode which has not yet been
1209  * already been deactivated (VOP_INACTIVE), or on a vnode which has
1210  * already been reclaimed.
1211  *
1212  * This routine is not responsible for placing us back on the freelist.
1213  * Instead, it happens automatically when the caller releases the VX lock
1214  * (assuming there aren't any other references).
1215  */
1216 void
1217 vgone(struct vnode *vp)
1218 {
1219 	/*
1220 	 * assert that the VX lock is held.  This is an absolute requirement
1221 	 * now for vgone() to be called.
1222 	 */
1223 	KKASSERT(vp->v_lock.lk_exclusivecount == 1);
1224 
1225 	/*
1226 	 * Clean out the filesystem specific data and set the VRECLAIMED
1227 	 * bit.  Also deactivate the vnode if necessary.
1228 	 */
1229 	vclean(vp, DOCLOSE, curthread);
1230 
1231 	/*
1232 	 * Delete from old mount point vnode list, if on one.
1233 	 */
1234 	if (vp->v_mount != NULL)
1235 		insmntque(vp, NULL);
1236 
1237 	/*
1238 	 * If special device, remove it from special device alias list
1239 	 * if it is on one.  This should normally only occur if a vnode is
1240 	 * being revoked as the device should otherwise have been released
1241 	 * naturally.
1242 	 */
1243 	if ((vp->v_type == VBLK || vp->v_type == VCHR) && vp->v_rdev != NULL) {
1244 		v_release_rdev(vp);
1245 	}
1246 
1247 	/*
1248 	 * Set us to VBAD
1249 	 */
1250 	vp->v_type = VBAD;
1251 }
1252 
1253 /*
1254  * Lookup a vnode by device number.
1255  */
1256 int
1257 vfinddev(dev_t dev, enum vtype type, struct vnode **vpp)
1258 {
1259 	lwkt_tokref ilock;
1260 	struct vnode *vp;
1261 
1262 	lwkt_gettoken(&ilock, &spechash_token);
1263 	SLIST_FOREACH(vp, &dev->si_hlist, v_specnext) {
1264 		if (type == vp->v_type) {
1265 			*vpp = vp;
1266 			lwkt_reltoken(&ilock);
1267 			return (1);
1268 		}
1269 	}
1270 	lwkt_reltoken(&ilock);
1271 	return (0);
1272 }
1273 
1274 /*
1275  * Calculate the total number of references to a special device.  This
1276  * routine may only be called for VBLK and VCHR vnodes since v_rdev is
1277  * an overloaded field.  Since udev2dev can now return NODEV, we have
1278  * to check for a NULL v_rdev.
1279  */
1280 int
1281 count_dev(dev_t dev)
1282 {
1283 	lwkt_tokref ilock;
1284 	struct vnode *vp;
1285 	int count = 0;
1286 
1287 	if (SLIST_FIRST(&dev->si_hlist)) {
1288 		lwkt_gettoken(&ilock, &spechash_token);
1289 		SLIST_FOREACH(vp, &dev->si_hlist, v_specnext) {
1290 			count += vp->v_usecount;
1291 		}
1292 		lwkt_reltoken(&ilock);
1293 	}
1294 	return(count);
1295 }
1296 
1297 int
1298 count_udev(udev_t udev)
1299 {
1300 	dev_t dev;
1301 
1302 	if ((dev = udev2dev(udev, 0)) == NODEV)
1303 		return(0);
1304 	return(count_dev(dev));
1305 }
1306 
1307 int
1308 vcount(struct vnode *vp)
1309 {
1310 	if (vp->v_rdev == NULL)
1311 		return(0);
1312 	return(count_dev(vp->v_rdev));
1313 }
1314 
1315 /*
1316  * Print out a description of a vnode.
1317  */
1318 static char *typename[] =
1319 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
1320 
1321 void
1322 vprint(char *label, struct vnode *vp)
1323 {
1324 	char buf[96];
1325 
1326 	if (label != NULL)
1327 		printf("%s: %p: ", label, (void *)vp);
1328 	else
1329 		printf("%p: ", (void *)vp);
1330 	printf("type %s, usecount %d, writecount %d, refcount %d,",
1331 	    typename[vp->v_type], vp->v_usecount, vp->v_writecount,
1332 	    vp->v_holdcnt);
1333 	buf[0] = '\0';
1334 	if (vp->v_flag & VROOT)
1335 		strcat(buf, "|VROOT");
1336 	if (vp->v_flag & VTEXT)
1337 		strcat(buf, "|VTEXT");
1338 	if (vp->v_flag & VSYSTEM)
1339 		strcat(buf, "|VSYSTEM");
1340 	if (vp->v_flag & VBWAIT)
1341 		strcat(buf, "|VBWAIT");
1342 	if (vp->v_flag & VFREE)
1343 		strcat(buf, "|VFREE");
1344 	if (vp->v_flag & VOBJBUF)
1345 		strcat(buf, "|VOBJBUF");
1346 	if (buf[0] != '\0')
1347 		printf(" flags (%s)", &buf[1]);
1348 	if (vp->v_data == NULL) {
1349 		printf("\n");
1350 	} else {
1351 		printf("\n\t");
1352 		VOP_PRINT(vp);
1353 	}
1354 }
1355 
1356 #ifdef DDB
1357 #include <ddb/ddb.h>
1358 
1359 static int db_show_locked_vnodes(struct mount *mp, void *data);
1360 
1361 /*
1362  * List all of the locked vnodes in the system.
1363  * Called when debugging the kernel.
1364  */
1365 DB_SHOW_COMMAND(lockedvnodes, lockedvnodes)
1366 {
1367 	printf("Locked vnodes\n");
1368 	mountlist_scan(db_show_locked_vnodes, NULL,
1369 			MNTSCAN_FORWARD|MNTSCAN_NOBUSY);
1370 }
1371 
1372 static int
1373 db_show_locked_vnodes(struct mount *mp, void *data __unused)
1374 {
1375 	struct vnode *vp;
1376 
1377 	TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
1378 		if (VOP_ISLOCKED(vp, NULL))
1379 			vprint((char *)0, vp);
1380 	}
1381 	return(0);
1382 }
1383 #endif
1384 
1385 /*
1386  * Top level filesystem related information gathering.
1387  */
1388 static int	sysctl_ovfs_conf (SYSCTL_HANDLER_ARGS);
1389 
1390 static int
1391 vfs_sysctl(SYSCTL_HANDLER_ARGS)
1392 {
1393 	int *name = (int *)arg1 - 1;	/* XXX */
1394 	u_int namelen = arg2 + 1;	/* XXX */
1395 	struct vfsconf *vfsp;
1396 
1397 #if 1 || defined(COMPAT_PRELITE2)
1398 	/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
1399 	if (namelen == 1)
1400 		return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
1401 #endif
1402 
1403 #ifdef notyet
1404 	/* all sysctl names at this level are at least name and field */
1405 	if (namelen < 2)
1406 		return (ENOTDIR);		/* overloaded */
1407 	if (name[0] != VFS_GENERIC) {
1408 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
1409 			if (vfsp->vfc_typenum == name[0])
1410 				break;
1411 		if (vfsp == NULL)
1412 			return (EOPNOTSUPP);
1413 		return ((*vfsp->vfc_vfsops->vfs_sysctl)(&name[1], namelen - 1,
1414 		    oldp, oldlenp, newp, newlen, p));
1415 	}
1416 #endif
1417 	switch (name[1]) {
1418 	case VFS_MAXTYPENUM:
1419 		if (namelen != 2)
1420 			return (ENOTDIR);
1421 		return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
1422 	case VFS_CONF:
1423 		if (namelen != 3)
1424 			return (ENOTDIR);	/* overloaded */
1425 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
1426 			if (vfsp->vfc_typenum == name[2])
1427 				break;
1428 		if (vfsp == NULL)
1429 			return (EOPNOTSUPP);
1430 		return (SYSCTL_OUT(req, vfsp, sizeof *vfsp));
1431 	}
1432 	return (EOPNOTSUPP);
1433 }
1434 
1435 SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD, vfs_sysctl,
1436 	"Generic filesystem");
1437 
1438 #if 1 || defined(COMPAT_PRELITE2)
1439 
1440 static int
1441 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
1442 {
1443 	int error;
1444 	struct vfsconf *vfsp;
1445 	struct ovfsconf ovfs;
1446 
1447 	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
1448 		ovfs.vfc_vfsops = vfsp->vfc_vfsops;	/* XXX used as flag */
1449 		strcpy(ovfs.vfc_name, vfsp->vfc_name);
1450 		ovfs.vfc_index = vfsp->vfc_typenum;
1451 		ovfs.vfc_refcount = vfsp->vfc_refcount;
1452 		ovfs.vfc_flags = vfsp->vfc_flags;
1453 		error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
1454 		if (error)
1455 			return error;
1456 	}
1457 	return 0;
1458 }
1459 
1460 #endif /* 1 || COMPAT_PRELITE2 */
1461 
1462 /*
1463  * Check to see if a filesystem is mounted on a block device.
1464  */
1465 int
1466 vfs_mountedon(struct vnode *vp)
1467 {
1468 	dev_t dev;
1469 
1470 	if ((dev = vp->v_rdev) == NULL)
1471 		dev = udev2dev(vp->v_udev, (vp->v_type == VBLK));
1472 	if (dev != NODEV && dev->si_mountpoint)
1473 		return (EBUSY);
1474 	return (0);
1475 }
1476 
1477 /*
1478  * Unmount all filesystems. The list is traversed in reverse order
1479  * of mounting to avoid dependencies.
1480  */
1481 
1482 static int vfs_umountall_callback(struct mount *mp, void *data);
1483 
1484 void
1485 vfs_unmountall(void)
1486 {
1487 	struct thread *td = curthread;
1488 	int count;
1489 
1490 	if (td->td_proc == NULL)
1491 		td = initproc->p_thread;	/* XXX XXX use proc0 instead? */
1492 
1493 	do {
1494 		count = mountlist_scan(vfs_umountall_callback,
1495 					&td, MNTSCAN_REVERSE|MNTSCAN_NOBUSY);
1496 	} while (count);
1497 }
1498 
1499 static
1500 int
1501 vfs_umountall_callback(struct mount *mp, void *data)
1502 {
1503 	struct thread *td = *(struct thread **)data;
1504 	int error;
1505 
1506 	error = dounmount(mp, MNT_FORCE, td);
1507 	if (error) {
1508 		mountlist_remove(mp);
1509 		printf("unmount of filesystem mounted from %s failed (",
1510 			mp->mnt_stat.f_mntfromname);
1511 		if (error == EBUSY)
1512 			printf("BUSY)\n");
1513 		else
1514 			printf("%d)\n", error);
1515 	}
1516 	return(1);
1517 }
1518 
1519 /*
1520  * Build hash lists of net addresses and hang them off the mount point.
1521  * Called by ufs_mount() to set up the lists of export addresses.
1522  */
1523 static int
1524 vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
1525 		struct export_args *argp)
1526 {
1527 	struct netcred *np;
1528 	struct radix_node_head *rnh;
1529 	int i;
1530 	struct radix_node *rn;
1531 	struct sockaddr *saddr, *smask = 0;
1532 	struct domain *dom;
1533 	int error;
1534 
1535 	if (argp->ex_addrlen == 0) {
1536 		if (mp->mnt_flag & MNT_DEFEXPORTED)
1537 			return (EPERM);
1538 		np = &nep->ne_defexported;
1539 		np->netc_exflags = argp->ex_flags;
1540 		np->netc_anon = argp->ex_anon;
1541 		np->netc_anon.cr_ref = 1;
1542 		mp->mnt_flag |= MNT_DEFEXPORTED;
1543 		return (0);
1544 	}
1545 
1546 	if (argp->ex_addrlen < 0 || argp->ex_addrlen > MLEN)
1547 		return (EINVAL);
1548 	if (argp->ex_masklen < 0 || argp->ex_masklen > MLEN)
1549 		return (EINVAL);
1550 
1551 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
1552 	np = (struct netcred *) malloc(i, M_NETADDR, M_WAITOK);
1553 	bzero((caddr_t) np, i);
1554 	saddr = (struct sockaddr *) (np + 1);
1555 	if ((error = copyin(argp->ex_addr, (caddr_t) saddr, argp->ex_addrlen)))
1556 		goto out;
1557 	if (saddr->sa_len > argp->ex_addrlen)
1558 		saddr->sa_len = argp->ex_addrlen;
1559 	if (argp->ex_masklen) {
1560 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
1561 		error = copyin(argp->ex_mask, (caddr_t)smask, argp->ex_masklen);
1562 		if (error)
1563 			goto out;
1564 		if (smask->sa_len > argp->ex_masklen)
1565 			smask->sa_len = argp->ex_masklen;
1566 	}
1567 	i = saddr->sa_family;
1568 	if ((rnh = nep->ne_rtable[i]) == 0) {
1569 		/*
1570 		 * Seems silly to initialize every AF when most are not used,
1571 		 * do so on demand here
1572 		 */
1573 		SLIST_FOREACH(dom, &domains, dom_next)
1574 			if (dom->dom_family == i && dom->dom_rtattach) {
1575 				dom->dom_rtattach((void **) &nep->ne_rtable[i],
1576 				    dom->dom_rtoffset);
1577 				break;
1578 			}
1579 		if ((rnh = nep->ne_rtable[i]) == 0) {
1580 			error = ENOBUFS;
1581 			goto out;
1582 		}
1583 	}
1584 	rn = (*rnh->rnh_addaddr) ((char *) saddr, (char *) smask, rnh,
1585 	    np->netc_rnodes);
1586 	if (rn == 0 || np != (struct netcred *) rn) {	/* already exists */
1587 		error = EPERM;
1588 		goto out;
1589 	}
1590 	np->netc_exflags = argp->ex_flags;
1591 	np->netc_anon = argp->ex_anon;
1592 	np->netc_anon.cr_ref = 1;
1593 	return (0);
1594 out:
1595 	free(np, M_NETADDR);
1596 	return (error);
1597 }
1598 
1599 /* ARGSUSED */
1600 static int
1601 vfs_free_netcred(struct radix_node *rn, void *w)
1602 {
1603 	struct radix_node_head *rnh = (struct radix_node_head *) w;
1604 
1605 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
1606 	free((caddr_t) rn, M_NETADDR);
1607 	return (0);
1608 }
1609 
1610 /*
1611  * Free the net address hash lists that are hanging off the mount points.
1612  */
1613 static void
1614 vfs_free_addrlist(struct netexport *nep)
1615 {
1616 	int i;
1617 	struct radix_node_head *rnh;
1618 
1619 	for (i = 0; i <= AF_MAX; i++)
1620 		if ((rnh = nep->ne_rtable[i])) {
1621 			(*rnh->rnh_walktree) (rnh, vfs_free_netcred,
1622 			    (caddr_t) rnh);
1623 			free((caddr_t) rnh, M_RTABLE);
1624 			nep->ne_rtable[i] = 0;
1625 		}
1626 }
1627 
1628 int
1629 vfs_export(struct mount *mp, struct netexport *nep, struct export_args *argp)
1630 {
1631 	int error;
1632 
1633 	if (argp->ex_flags & MNT_DELEXPORT) {
1634 		if (mp->mnt_flag & MNT_EXPUBLIC) {
1635 			vfs_setpublicfs(NULL, NULL, NULL);
1636 			mp->mnt_flag &= ~MNT_EXPUBLIC;
1637 		}
1638 		vfs_free_addrlist(nep);
1639 		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
1640 	}
1641 	if (argp->ex_flags & MNT_EXPORTED) {
1642 		if (argp->ex_flags & MNT_EXPUBLIC) {
1643 			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
1644 				return (error);
1645 			mp->mnt_flag |= MNT_EXPUBLIC;
1646 		}
1647 		if ((error = vfs_hang_addrlist(mp, nep, argp)))
1648 			return (error);
1649 		mp->mnt_flag |= MNT_EXPORTED;
1650 	}
1651 	return (0);
1652 }
1653 
1654 
1655 /*
1656  * Set the publicly exported filesystem (WebNFS). Currently, only
1657  * one public filesystem is possible in the spec (RFC 2054 and 2055)
1658  */
1659 int
1660 vfs_setpublicfs(struct mount *mp, struct netexport *nep,
1661 		struct export_args *argp)
1662 {
1663 	int error;
1664 	struct vnode *rvp;
1665 	char *cp;
1666 
1667 	/*
1668 	 * mp == NULL -> invalidate the current info, the FS is
1669 	 * no longer exported. May be called from either vfs_export
1670 	 * or unmount, so check if it hasn't already been done.
1671 	 */
1672 	if (mp == NULL) {
1673 		if (nfs_pub.np_valid) {
1674 			nfs_pub.np_valid = 0;
1675 			if (nfs_pub.np_index != NULL) {
1676 				FREE(nfs_pub.np_index, M_TEMP);
1677 				nfs_pub.np_index = NULL;
1678 			}
1679 		}
1680 		return (0);
1681 	}
1682 
1683 	/*
1684 	 * Only one allowed at a time.
1685 	 */
1686 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
1687 		return (EBUSY);
1688 
1689 	/*
1690 	 * Get real filehandle for root of exported FS.
1691 	 */
1692 	bzero((caddr_t)&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
1693 	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
1694 
1695 	if ((error = VFS_ROOT(mp, &rvp)))
1696 		return (error);
1697 
1698 	if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
1699 		return (error);
1700 
1701 	vput(rvp);
1702 
1703 	/*
1704 	 * If an indexfile was specified, pull it in.
1705 	 */
1706 	if (argp->ex_indexfile != NULL) {
1707 		MALLOC(nfs_pub.np_index, char *, MAXNAMLEN + 1, M_TEMP,
1708 		    M_WAITOK);
1709 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
1710 		    MAXNAMLEN, (size_t *)0);
1711 		if (!error) {
1712 			/*
1713 			 * Check for illegal filenames.
1714 			 */
1715 			for (cp = nfs_pub.np_index; *cp; cp++) {
1716 				if (*cp == '/') {
1717 					error = EINVAL;
1718 					break;
1719 				}
1720 			}
1721 		}
1722 		if (error) {
1723 			FREE(nfs_pub.np_index, M_TEMP);
1724 			return (error);
1725 		}
1726 	}
1727 
1728 	nfs_pub.np_mount = mp;
1729 	nfs_pub.np_valid = 1;
1730 	return (0);
1731 }
1732 
1733 struct netcred *
1734 vfs_export_lookup(struct mount *mp, struct netexport *nep,
1735 		struct sockaddr *nam)
1736 {
1737 	struct netcred *np;
1738 	struct radix_node_head *rnh;
1739 	struct sockaddr *saddr;
1740 
1741 	np = NULL;
1742 	if (mp->mnt_flag & MNT_EXPORTED) {
1743 		/*
1744 		 * Lookup in the export list first.
1745 		 */
1746 		if (nam != NULL) {
1747 			saddr = nam;
1748 			rnh = nep->ne_rtable[saddr->sa_family];
1749 			if (rnh != NULL) {
1750 				np = (struct netcred *)
1751 					(*rnh->rnh_matchaddr)((char *)saddr,
1752 							      rnh);
1753 				if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
1754 					np = NULL;
1755 			}
1756 		}
1757 		/*
1758 		 * If no address match, use the default if it exists.
1759 		 */
1760 		if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
1761 			np = &nep->ne_defexported;
1762 	}
1763 	return (np);
1764 }
1765 
1766 /*
1767  * perform msync on all vnodes under a mount point.  The mount point must
1768  * be locked.  This code is also responsible for lazy-freeing unreferenced
1769  * vnodes whos VM objects no longer contain pages.
1770  *
1771  * NOTE: MNT_WAIT still skips vnodes in the VXLOCK state.
1772  */
1773 static int vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data);
1774 static int vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data);
1775 
1776 void
1777 vfs_msync(struct mount *mp, int flags)
1778 {
1779 	vmntvnodescan(mp, VMSC_REFVP, vfs_msync_scan1, vfs_msync_scan2,
1780 			(void *)flags);
1781 }
1782 
1783 /*
1784  * scan1 is a fast pre-check.  There could be hundreds of thousands of
1785  * vnodes, we cannot afford to do anything heavy weight until we have a
1786  * fairly good indication that there is work to do.
1787  */
1788 static
1789 int
1790 vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data)
1791 {
1792 	int flags = (int)data;
1793 
1794 	if ((vp->v_flag & VRECLAIMED) == 0) {
1795 		if (vshouldfree(vp, 0))
1796 			return(0);	/* call scan2 */
1797 		if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
1798 		    (vp->v_flag & VOBJDIRTY) &&
1799 		    (flags == MNT_WAIT || VOP_ISLOCKED(vp, NULL) == 0)) {
1800 			return(0);	/* call scan2 */
1801 		}
1802 	}
1803 
1804 	/*
1805 	 * do not call scan2, continue the loop
1806 	 */
1807 	return(-1);
1808 }
1809 
1810 static
1811 int
1812 vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data)
1813 {
1814 	vm_object_t obj;
1815 	int flags = (int)data;
1816 
1817 	if (vp->v_flag & VRECLAIMED)
1818 		return(0);
1819 
1820 	if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
1821 	    (vp->v_flag & VOBJDIRTY) &&
1822 	    (flags == MNT_WAIT || VOP_ISLOCKED(vp, NULL) == 0)) {
1823 		if (VOP_GETVOBJECT(vp, &obj) == 0) {
1824 			vm_object_page_clean(obj, 0, 0,
1825 			 flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
1826 		}
1827 	}
1828 	return(0);
1829 }
1830 
1831 /*
1832  * Create the VM object needed for VMIO and mmap support.  This
1833  * is done for all VREG files in the system.  Some filesystems might
1834  * afford the additional metadata buffering capability of the
1835  * VMIO code by making the device node be VMIO mode also.
1836  *
1837  * vp must be locked when vfs_object_create is called.
1838  */
1839 int
1840 vfs_object_create(struct vnode *vp, struct thread *td)
1841 {
1842 	return (VOP_CREATEVOBJECT(vp, td));
1843 }
1844 
1845 /*
1846  * Record a process's interest in events which might happen to
1847  * a vnode.  Because poll uses the historic select-style interface
1848  * internally, this routine serves as both the ``check for any
1849  * pending events'' and the ``record my interest in future events''
1850  * functions.  (These are done together, while the lock is held,
1851  * to avoid race conditions.)
1852  */
1853 int
1854 vn_pollrecord(struct vnode *vp, struct thread *td, int events)
1855 {
1856 	lwkt_tokref ilock;
1857 
1858 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
1859 	if (vp->v_pollinfo.vpi_revents & events) {
1860 		/*
1861 		 * This leaves events we are not interested
1862 		 * in available for the other process which
1863 		 * which presumably had requested them
1864 		 * (otherwise they would never have been
1865 		 * recorded).
1866 		 */
1867 		events &= vp->v_pollinfo.vpi_revents;
1868 		vp->v_pollinfo.vpi_revents &= ~events;
1869 
1870 		lwkt_reltoken(&ilock);
1871 		return events;
1872 	}
1873 	vp->v_pollinfo.vpi_events |= events;
1874 	selrecord(td, &vp->v_pollinfo.vpi_selinfo);
1875 	lwkt_reltoken(&ilock);
1876 	return 0;
1877 }
1878 
1879 /*
1880  * Note the occurrence of an event.  If the VN_POLLEVENT macro is used,
1881  * it is possible for us to miss an event due to race conditions, but
1882  * that condition is expected to be rare, so for the moment it is the
1883  * preferred interface.
1884  */
1885 void
1886 vn_pollevent(struct vnode *vp, int events)
1887 {
1888 	lwkt_tokref ilock;
1889 
1890 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
1891 	if (vp->v_pollinfo.vpi_events & events) {
1892 		/*
1893 		 * We clear vpi_events so that we don't
1894 		 * call selwakeup() twice if two events are
1895 		 * posted before the polling process(es) is
1896 		 * awakened.  This also ensures that we take at
1897 		 * most one selwakeup() if the polling process
1898 		 * is no longer interested.  However, it does
1899 		 * mean that only one event can be noticed at
1900 		 * a time.  (Perhaps we should only clear those
1901 		 * event bits which we note?) XXX
1902 		 */
1903 		vp->v_pollinfo.vpi_events = 0;	/* &= ~events ??? */
1904 		vp->v_pollinfo.vpi_revents |= events;
1905 		selwakeup(&vp->v_pollinfo.vpi_selinfo);
1906 	}
1907 	lwkt_reltoken(&ilock);
1908 }
1909 
1910 /*
1911  * Wake up anyone polling on vp because it is being revoked.
1912  * This depends on dead_poll() returning POLLHUP for correct
1913  * behavior.
1914  */
1915 void
1916 vn_pollgone(struct vnode *vp)
1917 {
1918 	lwkt_tokref ilock;
1919 
1920 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
1921 	if (vp->v_pollinfo.vpi_events) {
1922 		vp->v_pollinfo.vpi_events = 0;
1923 		selwakeup(&vp->v_pollinfo.vpi_selinfo);
1924 	}
1925 	lwkt_reltoken(&ilock);
1926 }
1927 
1928 /*
1929  * extract the dev_t from a VBLK or VCHR.  The vnode must have been opened
1930  * (or v_rdev might be NULL).
1931  */
1932 dev_t
1933 vn_todev(struct vnode *vp)
1934 {
1935 	if (vp->v_type != VBLK && vp->v_type != VCHR)
1936 		return (NODEV);
1937 	KKASSERT(vp->v_rdev != NULL);
1938 	return (vp->v_rdev);
1939 }
1940 
1941 /*
1942  * Check if vnode represents a disk device.  The vnode does not need to be
1943  * opened.
1944  */
1945 int
1946 vn_isdisk(struct vnode *vp, int *errp)
1947 {
1948 	dev_t dev;
1949 
1950 	if (vp->v_type != VBLK && vp->v_type != VCHR) {
1951 		if (errp != NULL)
1952 			*errp = ENOTBLK;
1953 		return (0);
1954 	}
1955 
1956 	if ((dev = vp->v_rdev) == NULL)
1957 		dev = udev2dev(vp->v_udev, (vp->v_type == VBLK));
1958 	if (dev == NULL || dev == NODEV) {
1959 		if (errp != NULL)
1960 			*errp = ENXIO;
1961 		return (0);
1962 	}
1963 	if (dev_is_good(dev) == 0) {
1964 		if (errp != NULL)
1965 			*errp = ENXIO;
1966 		return (0);
1967 	}
1968 	if ((dev_dflags(dev) & D_DISK) == 0) {
1969 		if (errp != NULL)
1970 			*errp = ENOTBLK;
1971 		return (0);
1972 	}
1973 	if (errp != NULL)
1974 		*errp = 0;
1975 	return (1);
1976 }
1977 
1978 #ifdef DEBUG_VFS_LOCKS
1979 
1980 void
1981 assert_vop_locked(struct vnode *vp, const char *str)
1982 {
1983 	if (vp && IS_LOCKING_VFS(vp) && !VOP_ISLOCKED(vp, NULL)) {
1984 		panic("%s: %p is not locked shared but should be", str, vp);
1985 	}
1986 }
1987 
1988 void
1989 assert_vop_unlocked(struct vnode *vp, const char *str)
1990 {
1991 	if (vp && IS_LOCKING_VFS(vp)) {
1992 		if (VOP_ISLOCKED(vp, curthread) == LK_EXCLUSIVE) {
1993 			panic("%s: %p is locked but should not be", str, vp);
1994 		}
1995 	}
1996 }
1997 
1998 #endif
1999