xref: /dragonfly/sys/kern/vfs_subr.c (revision 521a7b05)
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 1.104 2007/05/09 00:53:34 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 #include <sys/sysref2.h>
87 
88 static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
89 
90 int numvnodes;
91 SYSCTL_INT(_debug, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0, "");
92 int vfs_fastdev = 1;
93 SYSCTL_INT(_vfs, OID_AUTO, fastdev, CTLFLAG_RW, &vfs_fastdev, 0, "");
94 
95 enum vtype iftovt_tab[16] = {
96 	VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
97 	VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
98 };
99 int vttoif_tab[9] = {
100 	0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
101 	S_IFSOCK, S_IFIFO, S_IFMT,
102 };
103 
104 static int reassignbufcalls;
105 SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW,
106 		&reassignbufcalls, 0, "");
107 static int reassignbufloops;
108 SYSCTL_INT(_vfs, OID_AUTO, reassignbufloops, CTLFLAG_RW,
109 		&reassignbufloops, 0, "");
110 static int reassignbufsortgood;
111 SYSCTL_INT(_vfs, OID_AUTO, reassignbufsortgood, CTLFLAG_RW,
112 		&reassignbufsortgood, 0, "");
113 static int reassignbufsortbad;
114 SYSCTL_INT(_vfs, OID_AUTO, reassignbufsortbad, CTLFLAG_RW,
115 		&reassignbufsortbad, 0, "");
116 static int reassignbufmethod = 1;
117 SYSCTL_INT(_vfs, OID_AUTO, reassignbufmethod, CTLFLAG_RW,
118 		&reassignbufmethod, 0, "");
119 
120 int	nfs_mount_type = -1;
121 static struct lwkt_token spechash_token;
122 struct nfs_public nfs_pub;	/* publicly exported FS */
123 
124 int desiredvnodes;
125 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
126 		&desiredvnodes, 0, "Maximum number of vnodes");
127 
128 static void	vfs_free_addrlist (struct netexport *nep);
129 static int	vfs_free_netcred (struct radix_node *rn, void *w);
130 static int	vfs_hang_addrlist (struct mount *mp, struct netexport *nep,
131 				       struct export_args *argp);
132 
133 extern int dev_ref_debug;
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, off_t, b_loffset);
140 RB_GENERATE2(buf_rb_hash, buf, b_rbhash, rb_buf_compare, off_t, b_loffset);
141 
142 static int
143 rb_buf_compare(struct buf *b1, struct buf *b2)
144 {
145 	if (b1->b_loffset < b2->b_loffset)
146 		return(-1);
147 	if (b1->b_loffset > b2->b_loffset)
148 		return(1);
149 	return(0);
150 }
151 
152 /*
153  * Returns non-zero if the vnode is a candidate for lazy msyncing.
154  */
155 static __inline int
156 vshouldmsync(struct vnode *vp)
157 {
158 	if (vp->v_auxrefs != 0 || vp->v_sysref.refcnt > 0)
159 		return (0);		/* other holders */
160 	if (vp->v_object &&
161 	    (vp->v_object->ref_count || vp->v_object->resident_page_count)) {
162 		return (0);
163 	}
164 	return (1);
165 }
166 
167 /*
168  * Initialize the vnode management data structures.
169  *
170  * Called from vfsinit()
171  */
172 void
173 vfs_subr_init(void)
174 {
175 	/*
176 	 * Desired vnodes is a result of the physical page count
177 	 * and the size of kernel's heap.  It scales in proportion
178 	 * to the amount of available physical memory.  This can
179 	 * cause trouble on 64-bit and large memory platforms.
180 	 */
181 	/* desiredvnodes = maxproc + vmstats.v_page_count / 4; */
182 	desiredvnodes =
183 		min(maxproc + vmstats.v_page_count / 4,
184 		    2 * KvaSize /
185 		    (5 * (sizeof(struct vm_object) + sizeof(struct vnode))));
186 
187 	lwkt_token_init(&spechash_token);
188 }
189 
190 /*
191  * Knob to control the precision of file timestamps:
192  *
193  *   0 = seconds only; nanoseconds zeroed.
194  *   1 = seconds and nanoseconds, accurate within 1/HZ.
195  *   2 = seconds and nanoseconds, truncated to microseconds.
196  * >=3 = seconds and nanoseconds, maximum precision.
197  */
198 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
199 
200 static int timestamp_precision = TSP_SEC;
201 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
202 		&timestamp_precision, 0, "");
203 
204 /*
205  * Get a current timestamp.
206  */
207 void
208 vfs_timestamp(struct timespec *tsp)
209 {
210 	struct timeval tv;
211 
212 	switch (timestamp_precision) {
213 	case TSP_SEC:
214 		tsp->tv_sec = time_second;
215 		tsp->tv_nsec = 0;
216 		break;
217 	case TSP_HZ:
218 		getnanotime(tsp);
219 		break;
220 	case TSP_USEC:
221 		microtime(&tv);
222 		TIMEVAL_TO_TIMESPEC(&tv, tsp);
223 		break;
224 	case TSP_NSEC:
225 	default:
226 		nanotime(tsp);
227 		break;
228 	}
229 }
230 
231 /*
232  * Set vnode attributes to VNOVAL
233  */
234 void
235 vattr_null(struct vattr *vap)
236 {
237 	vap->va_type = VNON;
238 	vap->va_size = VNOVAL;
239 	vap->va_bytes = VNOVAL;
240 	vap->va_mode = VNOVAL;
241 	vap->va_nlink = VNOVAL;
242 	vap->va_uid = VNOVAL;
243 	vap->va_gid = VNOVAL;
244 	vap->va_fsid = VNOVAL;
245 	vap->va_fileid = VNOVAL;
246 	vap->va_blocksize = VNOVAL;
247 	vap->va_rmajor = VNOVAL;
248 	vap->va_rminor = 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 	vap->va_fsmid = VNOVAL;
259 }
260 
261 /*
262  * Flush out and invalidate all buffers associated with a vnode.
263  *
264  * vp must be locked.
265  */
266 static int vinvalbuf_bp(struct buf *bp, void *data);
267 
268 struct vinvalbuf_bp_info {
269 	struct vnode *vp;
270 	int slptimeo;
271 	int lkflags;
272 	int flags;
273 };
274 
275 void
276 vupdatefsmid(struct vnode *vp)
277 {
278 	atomic_set_int(&vp->v_flag, VFSMID);
279 }
280 
281 int
282 vinvalbuf(struct vnode *vp, int flags, int slpflag, int slptimeo)
283 {
284 	struct vinvalbuf_bp_info info;
285 	int error;
286 	vm_object_t object;
287 
288 	/*
289 	 * If we are being asked to save, call fsync to ensure that the inode
290 	 * is updated.
291 	 */
292 	if (flags & V_SAVE) {
293 		crit_enter();
294 		while (vp->v_track_write.bk_active) {
295 			vp->v_track_write.bk_waitflag = 1;
296 			error = tsleep(&vp->v_track_write, slpflag,
297 					"vinvlbuf", slptimeo);
298 			if (error) {
299 				crit_exit();
300 				return (error);
301 			}
302 		}
303 		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
304 			crit_exit();
305 			if ((error = VOP_FSYNC(vp, MNT_WAIT)) != 0)
306 				return (error);
307 			crit_enter();
308 			if (vp->v_track_write.bk_active > 0 ||
309 			    !RB_EMPTY(&vp->v_rbdirty_tree))
310 				panic("vinvalbuf: dirty bufs");
311 		}
312 		crit_exit();
313   	}
314 	crit_enter();
315 	info.slptimeo = slptimeo;
316 	info.lkflags = LK_EXCLUSIVE | LK_SLEEPFAIL;
317 	if (slpflag & PCATCH)
318 		info.lkflags |= LK_PCATCH;
319 	info.flags = flags;
320 	info.vp = vp;
321 
322 	/*
323 	 * Flush the buffer cache until nothing is left.
324 	 */
325 	while (!RB_EMPTY(&vp->v_rbclean_tree) ||
326 	    !RB_EMPTY(&vp->v_rbdirty_tree)) {
327 		error = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree, NULL,
328 				vinvalbuf_bp, &info);
329 		if (error == 0) {
330 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
331 					vinvalbuf_bp, &info);
332 		}
333 	}
334 
335 	/*
336 	 * Wait for I/O to complete.  XXX needs cleaning up.  The vnode can
337 	 * have write I/O in-progress but if there is a VM object then the
338 	 * VM object can also have read-I/O in-progress.
339 	 */
340 	do {
341 		while (vp->v_track_write.bk_active > 0) {
342 			vp->v_track_write.bk_waitflag = 1;
343 			tsleep(&vp->v_track_write, 0, "vnvlbv", 0);
344 		}
345 		if ((object = vp->v_object) != NULL) {
346 			while (object->paging_in_progress)
347 				vm_object_pip_sleep(object, "vnvlbx");
348 		}
349 	} while (vp->v_track_write.bk_active > 0);
350 
351 	crit_exit();
352 
353 	/*
354 	 * Destroy the copy in the VM cache, too.
355 	 */
356 	if ((object = vp->v_object) != NULL) {
357 		vm_object_page_remove(object, 0, 0,
358 			(flags & V_SAVE) ? TRUE : FALSE);
359 	}
360 
361 	if (!RB_EMPTY(&vp->v_rbdirty_tree) || !RB_EMPTY(&vp->v_rbclean_tree))
362 		panic("vinvalbuf: flush failed");
363 	if (!RB_EMPTY(&vp->v_rbhash_tree))
364 		panic("vinvalbuf: flush failed, buffers still present");
365 	return (0);
366 }
367 
368 static int
369 vinvalbuf_bp(struct buf *bp, void *data)
370 {
371 	struct vinvalbuf_bp_info *info = data;
372 	int error;
373 
374 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
375 		error = BUF_TIMELOCK(bp, info->lkflags,
376 				     "vinvalbuf", info->slptimeo);
377 		if (error == 0) {
378 			BUF_UNLOCK(bp);
379 			error = ENOLCK;
380 		}
381 		if (error == ENOLCK)
382 			return(0);
383 		return (-error);
384 	}
385 
386 	KKASSERT(bp->b_vp == info->vp);
387 
388 	/*
389 	 * XXX Since there are no node locks for NFS, I
390 	 * believe there is a slight chance that a delayed
391 	 * write will occur while sleeping just above, so
392 	 * check for it.  Note that vfs_bio_awrite expects
393 	 * buffers to reside on a queue, while bwrite() and
394 	 * brelse() do not.
395 	 */
396 	if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
397 	    (info->flags & V_SAVE)) {
398 		if (bp->b_vp == info->vp) {
399 			if (bp->b_flags & B_CLUSTEROK) {
400 				vfs_bio_awrite(bp);
401 			} else {
402 				bremfree(bp);
403 				bp->b_flags |= B_ASYNC;
404 				bwrite(bp);
405 			}
406 		} else {
407 			bremfree(bp);
408 			bwrite(bp);
409 		}
410 	} else if (info->flags & V_SAVE) {
411 		/*
412 		 * Cannot set B_NOCACHE on a clean buffer as this will
413 		 * destroy the VM backing store which might actually
414 		 * be dirty (and unsynchronized).
415 		 */
416 		bremfree(bp);
417 		bp->b_flags |= (B_INVAL | B_RELBUF);
418 		bp->b_flags &= ~B_ASYNC;
419 		brelse(bp);
420 	} else {
421 		bremfree(bp);
422 		bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
423 		bp->b_flags &= ~B_ASYNC;
424 		brelse(bp);
425 	}
426 	return(0);
427 }
428 
429 /*
430  * Truncate a file's buffer and pages to a specified length.  This
431  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
432  * sync activity.
433  *
434  * The vnode must be locked.
435  */
436 static int vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data);
437 static int vtruncbuf_bp_trunc(struct buf *bp, void *data);
438 static int vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data);
439 static int vtruncbuf_bp_metasync(struct buf *bp, void *data);
440 
441 int
442 vtruncbuf(struct vnode *vp, off_t length, int blksize)
443 {
444 	off_t truncloffset;
445 	int count;
446 	const char *filename;
447 
448 	/*
449 	 * Round up to the *next* block, then destroy the buffers in question.
450 	 * Since we are only removing some of the buffers we must rely on the
451 	 * scan count to determine whether a loop is necessary.
452 	 */
453 	if ((count = (int)(length % blksize)) != 0)
454 		truncloffset = length + (blksize - count);
455 	else
456 		truncloffset = length;
457 
458 	crit_enter();
459 	do {
460 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
461 				vtruncbuf_bp_trunc_cmp,
462 				vtruncbuf_bp_trunc, &truncloffset);
463 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
464 				vtruncbuf_bp_trunc_cmp,
465 				vtruncbuf_bp_trunc, &truncloffset);
466 	} while(count);
467 
468 	/*
469 	 * For safety, fsync any remaining metadata if the file is not being
470 	 * truncated to 0.  Since the metadata does not represent the entire
471 	 * dirty list we have to rely on the hit count to ensure that we get
472 	 * all of it.
473 	 */
474 	if (length > 0) {
475 		do {
476 			count = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
477 					vtruncbuf_bp_metasync_cmp,
478 					vtruncbuf_bp_metasync, vp);
479 		} while (count);
480 	}
481 
482 	/*
483 	 * Clean out any left over VM backing store.
484 	 */
485 	crit_exit();
486 
487 	vnode_pager_setsize(vp, length);
488 
489 	crit_enter();
490 
491 	/*
492 	 * It is possible to have in-progress I/O from buffers that were
493 	 * not part of the truncation.  This should not happen if we
494 	 * are truncating to 0-length.
495 	 */
496 	filename = TAILQ_FIRST(&vp->v_namecache) ?
497 		   TAILQ_FIRST(&vp->v_namecache)->nc_name : "?";
498 
499 	while ((count = vp->v_track_write.bk_active) > 0) {
500 		vp->v_track_write.bk_waitflag = 1;
501 		tsleep(&vp->v_track_write, 0, "vbtrunc", 0);
502 		if (length == 0) {
503 			kprintf("Warning: vtruncbuf(): Had to wait for "
504 			       "%d buffer I/Os to finish in %s\n",
505 			       count, filename);
506 		}
507 	}
508 
509 	/*
510 	 * Make sure no buffers were instantiated while we were trying
511 	 * to clean out the remaining VM pages.  This could occur due
512 	 * to busy dirty VM pages being flushed out to disk.
513 	 */
514 	do {
515 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
516 				vtruncbuf_bp_trunc_cmp,
517 				vtruncbuf_bp_trunc, &truncloffset);
518 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
519 				vtruncbuf_bp_trunc_cmp,
520 				vtruncbuf_bp_trunc, &truncloffset);
521 		if (count) {
522 			kprintf("Warning: vtruncbuf():  Had to re-clean %d "
523 			       "left over buffers in %s\n", count, filename);
524 		}
525 	} while(count);
526 
527 	crit_exit();
528 
529 	return (0);
530 }
531 
532 /*
533  * The callback buffer is beyond the new file EOF and must be destroyed.
534  * Note that the compare function must conform to the RB_SCAN's requirements.
535  */
536 static
537 int
538 vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data)
539 {
540 	if (bp->b_loffset >= *(off_t *)data)
541 		return(0);
542 	return(-1);
543 }
544 
545 static
546 int
547 vtruncbuf_bp_trunc(struct buf *bp, void *data)
548 {
549 	/*
550 	 * Do not try to use a buffer we cannot immediately lock, but sleep
551 	 * anyway to prevent a livelock.  The code will loop until all buffers
552 	 * can be acted upon.
553 	 */
554 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
555 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
556 			BUF_UNLOCK(bp);
557 	} else {
558 		bremfree(bp);
559 		bp->b_flags |= (B_INVAL | B_RELBUF | B_NOCACHE);
560 		bp->b_flags &= ~B_ASYNC;
561 		brelse(bp);
562 	}
563 	return(1);
564 }
565 
566 /*
567  * Fsync all meta-data after truncating a file to be non-zero.  Only metadata
568  * blocks (with a negative loffset) are scanned.
569  * Note that the compare function must conform to the RB_SCAN's requirements.
570  */
571 static int
572 vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data)
573 {
574 	if (bp->b_loffset < 0)
575 		return(0);
576 	return(1);
577 }
578 
579 static int
580 vtruncbuf_bp_metasync(struct buf *bp, void *data)
581 {
582 	struct vnode *vp = data;
583 
584 	if (bp->b_flags & B_DELWRI) {
585 		/*
586 		 * Do not try to use a buffer we cannot immediately lock,
587 		 * but sleep anyway to prevent a livelock.  The code will
588 		 * loop until all buffers can be acted upon.
589 		 */
590 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
591 			if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
592 				BUF_UNLOCK(bp);
593 		} else {
594 			bremfree(bp);
595 			if (bp->b_vp == vp) {
596 				bp->b_flags |= B_ASYNC;
597 			} else {
598 				bp->b_flags &= ~B_ASYNC;
599 			}
600 			bwrite(bp);
601 		}
602 		return(1);
603 	} else {
604 		return(0);
605 	}
606 }
607 
608 /*
609  * vfsync - implements a multipass fsync on a file which understands
610  * dependancies and meta-data.  The passed vnode must be locked.  The
611  * waitfor argument may be MNT_WAIT or MNT_NOWAIT, or MNT_LAZY.
612  *
613  * When fsyncing data asynchronously just do one consolidated pass starting
614  * with the most negative block number.  This may not get all the data due
615  * to dependancies.
616  *
617  * When fsyncing data synchronously do a data pass, then a metadata pass,
618  * then do additional data+metadata passes to try to get all the data out.
619  */
620 static int vfsync_wait_output(struct vnode *vp,
621 			    int (*waitoutput)(struct vnode *, struct thread *));
622 static int vfsync_data_only_cmp(struct buf *bp, void *data);
623 static int vfsync_meta_only_cmp(struct buf *bp, void *data);
624 static int vfsync_lazy_range_cmp(struct buf *bp, void *data);
625 static int vfsync_bp(struct buf *bp, void *data);
626 
627 struct vfsync_info {
628 	struct vnode *vp;
629 	int synchronous;
630 	int syncdeps;
631 	int lazycount;
632 	int lazylimit;
633 	int skippedbufs;
634 	int (*checkdef)(struct buf *);
635 };
636 
637 int
638 vfsync(struct vnode *vp, int waitfor, int passes,
639 	int (*checkdef)(struct buf *),
640 	int (*waitoutput)(struct vnode *, struct thread *))
641 {
642 	struct vfsync_info info;
643 	int error;
644 
645 	bzero(&info, sizeof(info));
646 	info.vp = vp;
647 	if ((info.checkdef = checkdef) == NULL)
648 		info.syncdeps = 1;
649 
650 	crit_enter_id("vfsync");
651 
652 	switch(waitfor) {
653 	case MNT_LAZY:
654 		/*
655 		 * Lazy (filesystem syncer typ) Asynchronous plus limit the
656 		 * number of data (not meta) pages we try to flush to 1MB.
657 		 * A non-zero return means that lazy limit was reached.
658 		 */
659 		info.lazylimit = 1024 * 1024;
660 		info.syncdeps = 1;
661 		error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
662 				vfsync_lazy_range_cmp, vfsync_bp, &info);
663 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
664 				vfsync_meta_only_cmp, vfsync_bp, &info);
665 		if (error == 0)
666 			vp->v_lazyw = 0;
667 		else if (!RB_EMPTY(&vp->v_rbdirty_tree))
668 			vn_syncer_add_to_worklist(vp, 1);
669 		error = 0;
670 		break;
671 	case MNT_NOWAIT:
672 		/*
673 		 * Asynchronous.  Do a data-only pass and a meta-only pass.
674 		 */
675 		info.syncdeps = 1;
676 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
677 			vfsync_bp, &info);
678 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_meta_only_cmp,
679 			vfsync_bp, &info);
680 		error = 0;
681 		break;
682 	default:
683 		/*
684 		 * Synchronous.  Do a data-only pass, then a meta-data+data
685 		 * pass, then additional integrated passes to try to get
686 		 * all the dependancies flushed.
687 		 */
688 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
689 			vfsync_bp, &info);
690 		error = vfsync_wait_output(vp, waitoutput);
691 		if (error == 0) {
692 			info.skippedbufs = 0;
693 			RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
694 				vfsync_bp, &info);
695 			error = vfsync_wait_output(vp, waitoutput);
696 			if (info.skippedbufs)
697 				kprintf("Warning: vfsync skipped %d dirty bufs in pass2!\n", info.skippedbufs);
698 		}
699 		while (error == 0 && passes > 0 &&
700 		    !RB_EMPTY(&vp->v_rbdirty_tree)) {
701 			if (--passes == 0) {
702 				info.synchronous = 1;
703 				info.syncdeps = 1;
704 			}
705 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
706 				vfsync_bp, &info);
707 			if (error < 0)
708 				error = -error;
709 			info.syncdeps = 1;
710 			if (error == 0)
711 				error = vfsync_wait_output(vp, waitoutput);
712 		}
713 		break;
714 	}
715 	crit_exit_id("vfsync");
716 	return(error);
717 }
718 
719 static int
720 vfsync_wait_output(struct vnode *vp, int (*waitoutput)(struct vnode *, struct thread *))
721 {
722 	int error = 0;
723 
724 	while (vp->v_track_write.bk_active) {
725 		vp->v_track_write.bk_waitflag = 1;
726 		tsleep(&vp->v_track_write, 0, "fsfsn", 0);
727 	}
728 	if (waitoutput)
729 		error = waitoutput(vp, curthread);
730 	return(error);
731 }
732 
733 static int
734 vfsync_data_only_cmp(struct buf *bp, void *data)
735 {
736 	if (bp->b_loffset < 0)
737 		return(-1);
738 	return(0);
739 }
740 
741 static int
742 vfsync_meta_only_cmp(struct buf *bp, void *data)
743 {
744 	if (bp->b_loffset < 0)
745 		return(0);
746 	return(1);
747 }
748 
749 static int
750 vfsync_lazy_range_cmp(struct buf *bp, void *data)
751 {
752 	struct vfsync_info *info = data;
753 	if (bp->b_loffset < info->vp->v_lazyw)
754 		return(-1);
755 	return(0);
756 }
757 
758 static int
759 vfsync_bp(struct buf *bp, void *data)
760 {
761 	struct vfsync_info *info = data;
762 	struct vnode *vp = info->vp;
763 	int error;
764 
765 	/*
766 	 * if syncdeps is not set we do not try to write buffers which have
767 	 * dependancies.
768 	 */
769 	if (!info->synchronous && info->syncdeps == 0 && info->checkdef(bp))
770 		return(0);
771 
772 	/*
773 	 * Ignore buffers that we cannot immediately lock.  XXX
774 	 */
775 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
776 		kprintf("Warning: vfsync_bp skipping dirty buffer %p\n", bp);
777 		++info->skippedbufs;
778 		return(0);
779 	}
780 	if ((bp->b_flags & B_DELWRI) == 0)
781 		panic("vfsync_bp: buffer not dirty");
782 	if (vp != bp->b_vp)
783 		panic("vfsync_bp: buffer vp mismatch");
784 
785 	/*
786 	 * B_NEEDCOMMIT (primarily used by NFS) is a state where the buffer
787 	 * has been written but an additional handshake with the device
788 	 * is required before we can dispose of the buffer.  We have no idea
789 	 * how to do this so we have to skip these buffers.
790 	 */
791 	if (bp->b_flags & B_NEEDCOMMIT) {
792 		BUF_UNLOCK(bp);
793 		return(0);
794 	}
795 
796 	if (info->synchronous) {
797 		/*
798 		 * Synchronous flushing.  An error may be returned.
799 		 */
800 		bremfree(bp);
801 		crit_exit_id("vfsync");
802 		error = bwrite(bp);
803 		crit_enter_id("vfsync");
804 	} else {
805 		/*
806 		 * Asynchronous flushing.  A negative return value simply
807 		 * stops the scan and is not considered an error.  We use
808 		 * this to support limited MNT_LAZY flushes.
809 		 */
810 		vp->v_lazyw = bp->b_loffset;
811 		if ((vp->v_flag & VOBJBUF) && (bp->b_flags & B_CLUSTEROK)) {
812 			info->lazycount += vfs_bio_awrite(bp);
813 		} else {
814 			info->lazycount += bp->b_bufsize;
815 			bremfree(bp);
816 			crit_exit_id("vfsync");
817 			bawrite(bp);
818 			crit_enter_id("vfsync");
819 		}
820 		if (info->lazylimit && info->lazycount >= info->lazylimit)
821 			error = 1;
822 		else
823 			error = 0;
824 	}
825 	return(-error);
826 }
827 
828 /*
829  * Associate a buffer with a vnode.
830  */
831 void
832 bgetvp(struct vnode *vp, struct buf *bp)
833 {
834 	KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));
835 	KKASSERT((bp->b_flags & (B_HASHED|B_DELWRI|B_VNCLEAN|B_VNDIRTY)) == 0);
836 
837 	vhold(vp);
838 	/*
839 	 * Insert onto list for new vnode.
840 	 */
841 	crit_enter();
842 	bp->b_vp = vp;
843 	bp->b_flags |= B_HASHED;
844 	if (buf_rb_hash_RB_INSERT(&vp->v_rbhash_tree, bp))
845 		panic("reassignbuf: dup lblk vp %p bp %p", vp, bp);
846 
847 	bp->b_flags |= B_VNCLEAN;
848 	if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp))
849 		panic("reassignbuf: dup lblk/clean vp %p bp %p", vp, bp);
850 	crit_exit();
851 }
852 
853 /*
854  * Disassociate a buffer from a vnode.
855  */
856 void
857 brelvp(struct buf *bp)
858 {
859 	struct vnode *vp;
860 
861 	KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
862 
863 	/*
864 	 * Delete from old vnode list, if on one.
865 	 */
866 	vp = bp->b_vp;
867 	crit_enter();
868 	if (bp->b_flags & (B_VNDIRTY | B_VNCLEAN)) {
869 		if (bp->b_flags & B_VNDIRTY)
870 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
871 		else
872 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
873 		bp->b_flags &= ~(B_VNDIRTY | B_VNCLEAN);
874 	}
875 	if (bp->b_flags & B_HASHED) {
876 		buf_rb_hash_RB_REMOVE(&vp->v_rbhash_tree, bp);
877 		bp->b_flags &= ~B_HASHED;
878 	}
879 	if ((vp->v_flag & VONWORKLST) && RB_EMPTY(&vp->v_rbdirty_tree)) {
880 		vp->v_flag &= ~VONWORKLST;
881 		LIST_REMOVE(vp, v_synclist);
882 	}
883 	crit_exit();
884 	bp->b_vp = NULL;
885 	vdrop(vp);
886 }
887 
888 /*
889  * Reassign the buffer to the proper clean/dirty list based on B_DELWRI.
890  * This routine is called when the state of the B_DELWRI bit is changed.
891  */
892 void
893 reassignbuf(struct buf *bp)
894 {
895 	struct vnode *vp = bp->b_vp;
896 	int delay;
897 
898 	KKASSERT(vp != NULL);
899 	++reassignbufcalls;
900 
901 	/*
902 	 * B_PAGING flagged buffers cannot be reassigned because their vp
903 	 * is not fully linked in.
904 	 */
905 	if (bp->b_flags & B_PAGING)
906 		panic("cannot reassign paging buffer");
907 
908 	crit_enter();
909 	if (bp->b_flags & B_DELWRI) {
910 		/*
911 		 * Move to the dirty list, add the vnode to the worklist
912 		 */
913 		if (bp->b_flags & B_VNCLEAN) {
914 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
915 			bp->b_flags &= ~B_VNCLEAN;
916 		}
917 		if ((bp->b_flags & B_VNDIRTY) == 0) {
918 			if (buf_rb_tree_RB_INSERT(&vp->v_rbdirty_tree, bp)) {
919 				panic("reassignbuf: dup lblk vp %p bp %p",
920 				      vp, bp);
921 			}
922 			bp->b_flags |= B_VNDIRTY;
923 		}
924 		if ((vp->v_flag & VONWORKLST) == 0) {
925 			switch (vp->v_type) {
926 			case VDIR:
927 				delay = dirdelay;
928 				break;
929 			case VCHR:
930 			case VBLK:
931 				if (vp->v_rdev &&
932 				    vp->v_rdev->si_mountpoint != NULL) {
933 					delay = metadelay;
934 					break;
935 				}
936 				/* fall through */
937 			default:
938 				delay = filedelay;
939 			}
940 			vn_syncer_add_to_worklist(vp, delay);
941 		}
942 	} else {
943 		/*
944 		 * Move to the clean list, remove the vnode from the worklist
945 		 * if no dirty blocks remain.
946 		 */
947 		if (bp->b_flags & B_VNDIRTY) {
948 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
949 			bp->b_flags &= ~B_VNDIRTY;
950 		}
951 		if ((bp->b_flags & B_VNCLEAN) == 0) {
952 			if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp)) {
953 				panic("reassignbuf: dup lblk vp %p bp %p",
954 				      vp, bp);
955 			}
956 			bp->b_flags |= B_VNCLEAN;
957 		}
958 		if ((vp->v_flag & VONWORKLST) &&
959 		    RB_EMPTY(&vp->v_rbdirty_tree)) {
960 			vp->v_flag &= ~VONWORKLST;
961 			LIST_REMOVE(vp, v_synclist);
962 		}
963 	}
964 	crit_exit();
965 }
966 
967 /*
968  * Create a vnode for a block device.
969  * Used for mounting the root file system.
970  */
971 int
972 bdevvp(cdev_t dev, struct vnode **vpp)
973 {
974 	struct vnode *vp;
975 	struct vnode *nvp;
976 	int error;
977 
978 	if (dev == NULL) {
979 		*vpp = NULLVP;
980 		return (ENXIO);
981 	}
982 	error = getspecialvnode(VT_NON, NULL, &spec_vnode_vops_p, &nvp, 0, 0);
983 	if (error) {
984 		*vpp = NULLVP;
985 		return (error);
986 	}
987 	vp = nvp;
988 	vp->v_type = VCHR;
989 	vp->v_umajor = dev->si_umajor;
990 	vp->v_uminor = dev->si_uminor;
991 	vx_unlock(vp);
992 	*vpp = vp;
993 	return (0);
994 }
995 
996 int
997 v_associate_rdev(struct vnode *vp, cdev_t dev)
998 {
999 	lwkt_tokref ilock;
1000 
1001 	if (dev == NULL)
1002 		return(ENXIO);
1003 	if (dev_is_good(dev) == 0)
1004 		return(ENXIO);
1005 	KKASSERT(vp->v_rdev == NULL);
1006 	if (dev_ref_debug)
1007 		kprintf("Z1");
1008 	vp->v_rdev = reference_dev(dev);
1009 	lwkt_gettoken(&ilock, &spechash_token);
1010 	SLIST_INSERT_HEAD(&dev->si_hlist, vp, v_cdevnext);
1011 	lwkt_reltoken(&ilock);
1012 	return(0);
1013 }
1014 
1015 void
1016 v_release_rdev(struct vnode *vp)
1017 {
1018 	lwkt_tokref ilock;
1019 	cdev_t dev;
1020 
1021 	if ((dev = vp->v_rdev) != NULL) {
1022 		lwkt_gettoken(&ilock, &spechash_token);
1023 		SLIST_REMOVE(&dev->si_hlist, vp, vnode, v_cdevnext);
1024 		vp->v_rdev = NULL;
1025 		release_dev(dev);
1026 		lwkt_reltoken(&ilock);
1027 	}
1028 }
1029 
1030 /*
1031  * Add a vnode to the alias list hung off the cdev_t.  We only associate
1032  * the device number with the vnode.  The actual device is not associated
1033  * until the vnode is opened (usually in spec_open()), and will be
1034  * disassociated on last close.
1035  */
1036 void
1037 addaliasu(struct vnode *nvp, int x, int y)
1038 {
1039 	if (nvp->v_type != VBLK && nvp->v_type != VCHR)
1040 		panic("addaliasu on non-special vnode");
1041 	nvp->v_umajor = x;
1042 	nvp->v_uminor = y;
1043 }
1044 
1045 /*
1046  * Disassociate a vnode from its underlying filesystem.
1047  *
1048  * The vnode must be VX locked and referenced.  In all normal situations
1049  * there are no active references.  If vclean_vxlocked() is called while
1050  * there are active references, the vnode is being ripped out and we have
1051  * to call VOP_CLOSE() as appropriate before we can reclaim it.
1052  */
1053 void
1054 vclean_vxlocked(struct vnode *vp, int flags)
1055 {
1056 	int active;
1057 	int n;
1058 	vm_object_t object;
1059 
1060 	/*
1061 	 * If the vnode has already been reclaimed we have nothing to do.
1062 	 */
1063 	if (vp->v_flag & VRECLAIMED)
1064 		return;
1065 	vp->v_flag |= VRECLAIMED;
1066 
1067 	/*
1068 	 * Scrap the vfs cache
1069 	 */
1070 	while (cache_inval_vp(vp, 0) != 0) {
1071 		kprintf("Warning: vnode %p clean/cache_resolution race detected\n", vp);
1072 		tsleep(vp, 0, "vclninv", 2);
1073 	}
1074 
1075 	/*
1076 	 * Check to see if the vnode is in use. If so we have to reference it
1077 	 * before we clean it out so that its count cannot fall to zero and
1078 	 * generate a race against ourselves to recycle it.
1079 	 */
1080 	active = sysref_isactive(&vp->v_sysref);
1081 
1082 	/*
1083 	 * Clean out any buffers associated with the vnode and destroy its
1084 	 * object, if it has one.
1085 	 */
1086 	vinvalbuf(vp, V_SAVE, 0, 0);
1087 
1088 	/*
1089 	 * If purging an active vnode (typically during a forced unmount
1090 	 * or reboot), it must be closed and deactivated before being
1091 	 * reclaimed.  This isn't really all that safe, but what can
1092 	 * we do? XXX.
1093 	 *
1094 	 * Note that neither of these routines unlocks the vnode.
1095 	 */
1096 	if (active && (flags & DOCLOSE)) {
1097 		while ((n = vp->v_opencount) != 0) {
1098 			if (vp->v_writecount)
1099 				VOP_CLOSE(vp, FWRITE|FNONBLOCK);
1100 			else
1101 				VOP_CLOSE(vp, FNONBLOCK);
1102 			if (vp->v_opencount == n) {
1103 				kprintf("Warning: unable to force-close"
1104 				       " vnode %p\n", vp);
1105 				break;
1106 			}
1107 		}
1108 	}
1109 
1110 	/*
1111 	 * If the vnode has not be deactivated, deactivated it.  Deactivation
1112 	 * can create new buffers and VM pages so we have to call vinvalbuf()
1113 	 * again to make sure they all get flushed.
1114 	 *
1115 	 * This can occur if a file with a link count of 0 needs to be
1116 	 * truncated.
1117 	 */
1118 	if ((vp->v_flag & VINACTIVE) == 0) {
1119 		vp->v_flag |= VINACTIVE;
1120 		VOP_INACTIVE(vp);
1121 		vinvalbuf(vp, V_SAVE, 0, 0);
1122 	}
1123 
1124 	/*
1125 	 * If the vnode has an object, destroy it.
1126 	 */
1127 	if ((object = vp->v_object) != NULL) {
1128 		if (object->ref_count == 0) {
1129 			if ((object->flags & OBJ_DEAD) == 0)
1130 				vm_object_terminate(object);
1131 		} else {
1132 			vm_pager_deallocate(object);
1133 		}
1134 		vp->v_flag &= ~VOBJBUF;
1135 	}
1136 	KKASSERT((vp->v_flag & VOBJBUF) == 0);
1137 
1138 
1139 	/*
1140 	 * Reclaim the vnode.
1141 	 */
1142 	if (VOP_RECLAIM(vp))
1143 		panic("vclean: cannot reclaim");
1144 
1145 	/*
1146 	 * Done with purge, notify sleepers of the grim news.
1147 	 */
1148 	vp->v_ops = &dead_vnode_vops_p;
1149 	vn_pollgone(vp);
1150 	vp->v_tag = VT_NON;
1151 }
1152 
1153 /*
1154  * Eliminate all activity associated with the requested vnode
1155  * and with all vnodes aliased to the requested vnode.
1156  *
1157  * The vnode must be referenced and vx_lock()'d
1158  *
1159  * revoke { struct vnode *a_vp, int a_flags }
1160  */
1161 int
1162 vop_stdrevoke(struct vop_revoke_args *ap)
1163 {
1164 	struct vnode *vp, *vq;
1165 	lwkt_tokref ilock;
1166 	cdev_t dev;
1167 
1168 	KASSERT((ap->a_flags & REVOKEALL) != 0, ("vop_revoke"));
1169 
1170 	vp = ap->a_vp;
1171 
1172 	/*
1173 	 * If the vnode is already dead don't try to revoke it
1174 	 */
1175 	if (vp->v_flag & VRECLAIMED)
1176 		return (0);
1177 
1178 	/*
1179 	 * If the vnode has a device association, scrap all vnodes associated
1180 	 * with the device.  Don't let the device disappear on us while we
1181 	 * are scrapping the vnodes.
1182 	 *
1183 	 * The passed vp will probably show up in the list, do not VX lock
1184 	 * it twice!
1185 	 */
1186 	if (vp->v_type != VCHR)
1187 		return(0);
1188 	if ((dev = vp->v_rdev) == NULL) {
1189 		if ((dev = get_dev(vp->v_umajor, vp->v_uminor)) == NULL)
1190 			return(0);
1191 	}
1192 	reference_dev(dev);
1193 	lwkt_gettoken(&ilock, &spechash_token);
1194 	while ((vq = SLIST_FIRST(&dev->si_hlist)) != NULL) {
1195 		if (vp != vq)
1196 			vx_get(vq);
1197 		if (vq == SLIST_FIRST(&dev->si_hlist))
1198 			vgone_vxlocked(vq);
1199 		if (vp != vq)
1200 			vx_put(vq);
1201 	}
1202 	lwkt_reltoken(&ilock);
1203 	release_dev(dev);
1204 	return (0);
1205 }
1206 
1207 /*
1208  * This is called when the object underlying a vnode is being destroyed,
1209  * such as in a remove().  Try to recycle the vnode immediately if the
1210  * only active reference is our reference.
1211  */
1212 int
1213 vrecycle(struct vnode *vp)
1214 {
1215 	if (vp->v_sysref.refcnt == 1) {
1216 		vgone_vxlocked(vp);
1217 		return (1);
1218 	}
1219 	return (0);
1220 }
1221 
1222 /*
1223  * Eliminate all activity associated with a vnode in preparation for reuse.
1224  *
1225  * The vnode must be VX locked and refd and will remain VX locked and refd
1226  * on return.  This routine may be called with the vnode in any state, as
1227  * long as it is VX locked.  The vnode will be cleaned out and marked
1228  * VRECLAIMED but will not actually be reused until all existing refs and
1229  * holds go away.
1230  *
1231  * NOTE: This routine may be called on a vnode which has not yet been
1232  * already been deactivated (VOP_INACTIVE), or on a vnode which has
1233  * already been reclaimed.
1234  *
1235  * This routine is not responsible for placing us back on the freelist.
1236  * Instead, it happens automatically when the caller releases the VX lock
1237  * (assuming there aren't any other references).
1238  */
1239 
1240 void
1241 vgone_vxlocked(struct vnode *vp)
1242 {
1243 	/*
1244 	 * assert that the VX lock is held.  This is an absolute requirement
1245 	 * now for vgone_vxlocked() to be called.
1246 	 */
1247 	KKASSERT(vp->v_lock.lk_exclusivecount == 1);
1248 
1249 	/*
1250 	 * Clean out the filesystem specific data and set the VRECLAIMED
1251 	 * bit.  Also deactivate the vnode if necessary.
1252 	 */
1253 	vclean_vxlocked(vp, DOCLOSE);
1254 
1255 	/*
1256 	 * Delete from old mount point vnode list, if on one.
1257 	 */
1258 	if (vp->v_mount != NULL)
1259 		insmntque(vp, NULL);
1260 
1261 	/*
1262 	 * If special device, remove it from special device alias list
1263 	 * if it is on one.  This should normally only occur if a vnode is
1264 	 * being revoked as the device should otherwise have been released
1265 	 * naturally.
1266 	 */
1267 	if ((vp->v_type == VBLK || vp->v_type == VCHR) && vp->v_rdev != NULL) {
1268 		v_release_rdev(vp);
1269 	}
1270 
1271 	/*
1272 	 * Set us to VBAD
1273 	 */
1274 	vp->v_type = VBAD;
1275 }
1276 
1277 /*
1278  * Lookup a vnode by device number.
1279  */
1280 int
1281 vfinddev(cdev_t dev, enum vtype type, struct vnode **vpp)
1282 {
1283 	lwkt_tokref ilock;
1284 	struct vnode *vp;
1285 
1286 	lwkt_gettoken(&ilock, &spechash_token);
1287 	SLIST_FOREACH(vp, &dev->si_hlist, v_cdevnext) {
1288 		if (type == vp->v_type) {
1289 			*vpp = vp;
1290 			lwkt_reltoken(&ilock);
1291 			return (1);
1292 		}
1293 	}
1294 	lwkt_reltoken(&ilock);
1295 	return (0);
1296 }
1297 
1298 /*
1299  * Calculate the total number of references to a special device.  This
1300  * routine may only be called for VBLK and VCHR vnodes since v_rdev is
1301  * an overloaded field.  Since udev2dev can now return NULL, we have
1302  * to check for a NULL v_rdev.
1303  */
1304 int
1305 count_dev(cdev_t dev)
1306 {
1307 	lwkt_tokref ilock;
1308 	struct vnode *vp;
1309 	int count = 0;
1310 
1311 	if (SLIST_FIRST(&dev->si_hlist)) {
1312 		lwkt_gettoken(&ilock, &spechash_token);
1313 		SLIST_FOREACH(vp, &dev->si_hlist, v_cdevnext) {
1314 			if (vp->v_sysref.refcnt > 0)
1315 				count += vp->v_sysref.refcnt;
1316 		}
1317 		lwkt_reltoken(&ilock);
1318 	}
1319 	return(count);
1320 }
1321 
1322 int
1323 count_udev(int x, int y)
1324 {
1325 	cdev_t dev;
1326 
1327 	if ((dev = get_dev(x, y)) == NULL)
1328 		return(0);
1329 	return(count_dev(dev));
1330 }
1331 
1332 int
1333 vcount(struct vnode *vp)
1334 {
1335 	if (vp->v_rdev == NULL)
1336 		return(0);
1337 	return(count_dev(vp->v_rdev));
1338 }
1339 
1340 /*
1341  * Initialize VMIO for a vnode.  This routine MUST be called before a
1342  * VFS can issue buffer cache ops on a vnode.  It is typically called
1343  * when a vnode is initialized from its inode.
1344  */
1345 int
1346 vinitvmio(struct vnode *vp, off_t filesize)
1347 {
1348 	vm_object_t object;
1349 	int error = 0;
1350 
1351 retry:
1352 	if ((object = vp->v_object) == NULL) {
1353 		object = vnode_pager_alloc(vp, filesize, 0, 0);
1354 		/*
1355 		 * Dereference the reference we just created.  This assumes
1356 		 * that the object is associated with the vp.
1357 		 */
1358 		object->ref_count--;
1359 		vrele(vp);
1360 	} else {
1361 		if (object->flags & OBJ_DEAD) {
1362 			vn_unlock(vp);
1363 			tsleep(object, 0, "vodead", 0);
1364 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1365 			goto retry;
1366 		}
1367 	}
1368 	KASSERT(vp->v_object != NULL, ("vinitvmio: NULL object"));
1369 	vp->v_flag |= VOBJBUF;
1370 	return (error);
1371 }
1372 
1373 
1374 /*
1375  * Print out a description of a vnode.
1376  */
1377 static char *typename[] =
1378 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
1379 
1380 void
1381 vprint(char *label, struct vnode *vp)
1382 {
1383 	char buf[96];
1384 
1385 	if (label != NULL)
1386 		kprintf("%s: %p: ", label, (void *)vp);
1387 	else
1388 		kprintf("%p: ", (void *)vp);
1389 	kprintf("type %s, sysrefs %d, writecount %d, holdcnt %d,",
1390 		typename[vp->v_type],
1391 		vp->v_sysref.refcnt, vp->v_writecount, vp->v_auxrefs);
1392 	buf[0] = '\0';
1393 	if (vp->v_flag & VROOT)
1394 		strcat(buf, "|VROOT");
1395 	if (vp->v_flag & VTEXT)
1396 		strcat(buf, "|VTEXT");
1397 	if (vp->v_flag & VSYSTEM)
1398 		strcat(buf, "|VSYSTEM");
1399 	if (vp->v_flag & VFREE)
1400 		strcat(buf, "|VFREE");
1401 	if (vp->v_flag & VOBJBUF)
1402 		strcat(buf, "|VOBJBUF");
1403 	if (buf[0] != '\0')
1404 		kprintf(" flags (%s)", &buf[1]);
1405 	if (vp->v_data == NULL) {
1406 		kprintf("\n");
1407 	} else {
1408 		kprintf("\n\t");
1409 		VOP_PRINT(vp);
1410 	}
1411 }
1412 
1413 #ifdef DDB
1414 #include <ddb/ddb.h>
1415 
1416 static int db_show_locked_vnodes(struct mount *mp, void *data);
1417 
1418 /*
1419  * List all of the locked vnodes in the system.
1420  * Called when debugging the kernel.
1421  */
1422 DB_SHOW_COMMAND(lockedvnodes, lockedvnodes)
1423 {
1424 	kprintf("Locked vnodes\n");
1425 	mountlist_scan(db_show_locked_vnodes, NULL,
1426 			MNTSCAN_FORWARD|MNTSCAN_NOBUSY);
1427 }
1428 
1429 static int
1430 db_show_locked_vnodes(struct mount *mp, void *data __unused)
1431 {
1432 	struct vnode *vp;
1433 
1434 	TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
1435 		if (vn_islocked(vp))
1436 			vprint((char *)0, vp);
1437 	}
1438 	return(0);
1439 }
1440 #endif
1441 
1442 /*
1443  * Top level filesystem related information gathering.
1444  */
1445 static int	sysctl_ovfs_conf (SYSCTL_HANDLER_ARGS);
1446 
1447 static int
1448 vfs_sysctl(SYSCTL_HANDLER_ARGS)
1449 {
1450 	int *name = (int *)arg1 - 1;	/* XXX */
1451 	u_int namelen = arg2 + 1;	/* XXX */
1452 	struct vfsconf *vfsp;
1453 
1454 #if 1 || defined(COMPAT_PRELITE2)
1455 	/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
1456 	if (namelen == 1)
1457 		return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
1458 #endif
1459 
1460 #ifdef notyet
1461 	/* all sysctl names at this level are at least name and field */
1462 	if (namelen < 2)
1463 		return (ENOTDIR);		/* overloaded */
1464 	if (name[0] != VFS_GENERIC) {
1465 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
1466 			if (vfsp->vfc_typenum == name[0])
1467 				break;
1468 		if (vfsp == NULL)
1469 			return (EOPNOTSUPP);
1470 		return ((*vfsp->vfc_vfsops->vfs_sysctl)(&name[1], namelen - 1,
1471 		    oldp, oldlenp, newp, newlen, p));
1472 	}
1473 #endif
1474 	switch (name[1]) {
1475 	case VFS_MAXTYPENUM:
1476 		if (namelen != 2)
1477 			return (ENOTDIR);
1478 		return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
1479 	case VFS_CONF:
1480 		if (namelen != 3)
1481 			return (ENOTDIR);	/* overloaded */
1482 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
1483 			if (vfsp->vfc_typenum == name[2])
1484 				break;
1485 		if (vfsp == NULL)
1486 			return (EOPNOTSUPP);
1487 		return (SYSCTL_OUT(req, vfsp, sizeof *vfsp));
1488 	}
1489 	return (EOPNOTSUPP);
1490 }
1491 
1492 SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD, vfs_sysctl,
1493 	"Generic filesystem");
1494 
1495 #if 1 || defined(COMPAT_PRELITE2)
1496 
1497 static int
1498 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
1499 {
1500 	int error;
1501 	struct vfsconf *vfsp;
1502 	struct ovfsconf ovfs;
1503 
1504 	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
1505 		bzero(&ovfs, sizeof(ovfs));
1506 		ovfs.vfc_vfsops = vfsp->vfc_vfsops;	/* XXX used as flag */
1507 		strcpy(ovfs.vfc_name, vfsp->vfc_name);
1508 		ovfs.vfc_index = vfsp->vfc_typenum;
1509 		ovfs.vfc_refcount = vfsp->vfc_refcount;
1510 		ovfs.vfc_flags = vfsp->vfc_flags;
1511 		error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
1512 		if (error)
1513 			return error;
1514 	}
1515 	return 0;
1516 }
1517 
1518 #endif /* 1 || COMPAT_PRELITE2 */
1519 
1520 /*
1521  * Check to see if a filesystem is mounted on a block device.
1522  */
1523 int
1524 vfs_mountedon(struct vnode *vp)
1525 {
1526 	cdev_t dev;
1527 
1528 	if ((dev = vp->v_rdev) == NULL) {
1529 		if (vp->v_type != VBLK)
1530 			dev = get_dev(vp->v_uminor, vp->v_umajor);
1531 	}
1532 	if (dev != NULL && dev->si_mountpoint)
1533 		return (EBUSY);
1534 	return (0);
1535 }
1536 
1537 /*
1538  * Unmount all filesystems. The list is traversed in reverse order
1539  * of mounting to avoid dependencies.
1540  */
1541 
1542 static int vfs_umountall_callback(struct mount *mp, void *data);
1543 
1544 void
1545 vfs_unmountall(void)
1546 {
1547 	int count;
1548 
1549 	do {
1550 		count = mountlist_scan(vfs_umountall_callback,
1551 					NULL, MNTSCAN_REVERSE|MNTSCAN_NOBUSY);
1552 	} while (count);
1553 }
1554 
1555 static
1556 int
1557 vfs_umountall_callback(struct mount *mp, void *data)
1558 {
1559 	int error;
1560 
1561 	error = dounmount(mp, MNT_FORCE);
1562 	if (error) {
1563 		mountlist_remove(mp);
1564 		kprintf("unmount of filesystem mounted from %s failed (",
1565 			mp->mnt_stat.f_mntfromname);
1566 		if (error == EBUSY)
1567 			kprintf("BUSY)\n");
1568 		else
1569 			kprintf("%d)\n", error);
1570 	}
1571 	return(1);
1572 }
1573 
1574 /*
1575  * Build hash lists of net addresses and hang them off the mount point.
1576  * Called by ufs_mount() to set up the lists of export addresses.
1577  */
1578 static int
1579 vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
1580 		struct export_args *argp)
1581 {
1582 	struct netcred *np;
1583 	struct radix_node_head *rnh;
1584 	int i;
1585 	struct radix_node *rn;
1586 	struct sockaddr *saddr, *smask = 0;
1587 	struct domain *dom;
1588 	int error;
1589 
1590 	if (argp->ex_addrlen == 0) {
1591 		if (mp->mnt_flag & MNT_DEFEXPORTED)
1592 			return (EPERM);
1593 		np = &nep->ne_defexported;
1594 		np->netc_exflags = argp->ex_flags;
1595 		np->netc_anon = argp->ex_anon;
1596 		np->netc_anon.cr_ref = 1;
1597 		mp->mnt_flag |= MNT_DEFEXPORTED;
1598 		return (0);
1599 	}
1600 
1601 	if (argp->ex_addrlen < 0 || argp->ex_addrlen > MLEN)
1602 		return (EINVAL);
1603 	if (argp->ex_masklen < 0 || argp->ex_masklen > MLEN)
1604 		return (EINVAL);
1605 
1606 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
1607 	np = (struct netcred *) kmalloc(i, M_NETADDR, M_WAITOK);
1608 	bzero((caddr_t) np, i);
1609 	saddr = (struct sockaddr *) (np + 1);
1610 	if ((error = copyin(argp->ex_addr, (caddr_t) saddr, argp->ex_addrlen)))
1611 		goto out;
1612 	if (saddr->sa_len > argp->ex_addrlen)
1613 		saddr->sa_len = argp->ex_addrlen;
1614 	if (argp->ex_masklen) {
1615 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
1616 		error = copyin(argp->ex_mask, (caddr_t)smask, argp->ex_masklen);
1617 		if (error)
1618 			goto out;
1619 		if (smask->sa_len > argp->ex_masklen)
1620 			smask->sa_len = argp->ex_masklen;
1621 	}
1622 	i = saddr->sa_family;
1623 	if ((rnh = nep->ne_rtable[i]) == 0) {
1624 		/*
1625 		 * Seems silly to initialize every AF when most are not used,
1626 		 * do so on demand here
1627 		 */
1628 		SLIST_FOREACH(dom, &domains, dom_next)
1629 			if (dom->dom_family == i && dom->dom_rtattach) {
1630 				dom->dom_rtattach((void **) &nep->ne_rtable[i],
1631 				    dom->dom_rtoffset);
1632 				break;
1633 			}
1634 		if ((rnh = nep->ne_rtable[i]) == 0) {
1635 			error = ENOBUFS;
1636 			goto out;
1637 		}
1638 	}
1639 	rn = (*rnh->rnh_addaddr) ((char *) saddr, (char *) smask, rnh,
1640 	    np->netc_rnodes);
1641 	if (rn == 0 || np != (struct netcred *) rn) {	/* already exists */
1642 		error = EPERM;
1643 		goto out;
1644 	}
1645 	np->netc_exflags = argp->ex_flags;
1646 	np->netc_anon = argp->ex_anon;
1647 	np->netc_anon.cr_ref = 1;
1648 	return (0);
1649 out:
1650 	kfree(np, M_NETADDR);
1651 	return (error);
1652 }
1653 
1654 /* ARGSUSED */
1655 static int
1656 vfs_free_netcred(struct radix_node *rn, void *w)
1657 {
1658 	struct radix_node_head *rnh = (struct radix_node_head *) w;
1659 
1660 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
1661 	kfree((caddr_t) rn, M_NETADDR);
1662 	return (0);
1663 }
1664 
1665 /*
1666  * Free the net address hash lists that are hanging off the mount points.
1667  */
1668 static void
1669 vfs_free_addrlist(struct netexport *nep)
1670 {
1671 	int i;
1672 	struct radix_node_head *rnh;
1673 
1674 	for (i = 0; i <= AF_MAX; i++)
1675 		if ((rnh = nep->ne_rtable[i])) {
1676 			(*rnh->rnh_walktree) (rnh, vfs_free_netcred,
1677 			    (caddr_t) rnh);
1678 			kfree((caddr_t) rnh, M_RTABLE);
1679 			nep->ne_rtable[i] = 0;
1680 		}
1681 }
1682 
1683 int
1684 vfs_export(struct mount *mp, struct netexport *nep, struct export_args *argp)
1685 {
1686 	int error;
1687 
1688 	if (argp->ex_flags & MNT_DELEXPORT) {
1689 		if (mp->mnt_flag & MNT_EXPUBLIC) {
1690 			vfs_setpublicfs(NULL, NULL, NULL);
1691 			mp->mnt_flag &= ~MNT_EXPUBLIC;
1692 		}
1693 		vfs_free_addrlist(nep);
1694 		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
1695 	}
1696 	if (argp->ex_flags & MNT_EXPORTED) {
1697 		if (argp->ex_flags & MNT_EXPUBLIC) {
1698 			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
1699 				return (error);
1700 			mp->mnt_flag |= MNT_EXPUBLIC;
1701 		}
1702 		if ((error = vfs_hang_addrlist(mp, nep, argp)))
1703 			return (error);
1704 		mp->mnt_flag |= MNT_EXPORTED;
1705 	}
1706 	return (0);
1707 }
1708 
1709 
1710 /*
1711  * Set the publicly exported filesystem (WebNFS). Currently, only
1712  * one public filesystem is possible in the spec (RFC 2054 and 2055)
1713  */
1714 int
1715 vfs_setpublicfs(struct mount *mp, struct netexport *nep,
1716 		struct export_args *argp)
1717 {
1718 	int error;
1719 	struct vnode *rvp;
1720 	char *cp;
1721 
1722 	/*
1723 	 * mp == NULL -> invalidate the current info, the FS is
1724 	 * no longer exported. May be called from either vfs_export
1725 	 * or unmount, so check if it hasn't already been done.
1726 	 */
1727 	if (mp == NULL) {
1728 		if (nfs_pub.np_valid) {
1729 			nfs_pub.np_valid = 0;
1730 			if (nfs_pub.np_index != NULL) {
1731 				FREE(nfs_pub.np_index, M_TEMP);
1732 				nfs_pub.np_index = NULL;
1733 			}
1734 		}
1735 		return (0);
1736 	}
1737 
1738 	/*
1739 	 * Only one allowed at a time.
1740 	 */
1741 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
1742 		return (EBUSY);
1743 
1744 	/*
1745 	 * Get real filehandle for root of exported FS.
1746 	 */
1747 	bzero((caddr_t)&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
1748 	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
1749 
1750 	if ((error = VFS_ROOT(mp, &rvp)))
1751 		return (error);
1752 
1753 	if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
1754 		return (error);
1755 
1756 	vput(rvp);
1757 
1758 	/*
1759 	 * If an indexfile was specified, pull it in.
1760 	 */
1761 	if (argp->ex_indexfile != NULL) {
1762 		int namelen;
1763 
1764 		error = vn_get_namelen(rvp, &namelen);
1765 		if (error)
1766 			return (error);
1767 		MALLOC(nfs_pub.np_index, char *, namelen, M_TEMP,
1768 		    M_WAITOK);
1769 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
1770 		    namelen, (size_t *)0);
1771 		if (!error) {
1772 			/*
1773 			 * Check for illegal filenames.
1774 			 */
1775 			for (cp = nfs_pub.np_index; *cp; cp++) {
1776 				if (*cp == '/') {
1777 					error = EINVAL;
1778 					break;
1779 				}
1780 			}
1781 		}
1782 		if (error) {
1783 			FREE(nfs_pub.np_index, M_TEMP);
1784 			return (error);
1785 		}
1786 	}
1787 
1788 	nfs_pub.np_mount = mp;
1789 	nfs_pub.np_valid = 1;
1790 	return (0);
1791 }
1792 
1793 struct netcred *
1794 vfs_export_lookup(struct mount *mp, struct netexport *nep,
1795 		struct sockaddr *nam)
1796 {
1797 	struct netcred *np;
1798 	struct radix_node_head *rnh;
1799 	struct sockaddr *saddr;
1800 
1801 	np = NULL;
1802 	if (mp->mnt_flag & MNT_EXPORTED) {
1803 		/*
1804 		 * Lookup in the export list first.
1805 		 */
1806 		if (nam != NULL) {
1807 			saddr = nam;
1808 			rnh = nep->ne_rtable[saddr->sa_family];
1809 			if (rnh != NULL) {
1810 				np = (struct netcred *)
1811 					(*rnh->rnh_matchaddr)((char *)saddr,
1812 							      rnh);
1813 				if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
1814 					np = NULL;
1815 			}
1816 		}
1817 		/*
1818 		 * If no address match, use the default if it exists.
1819 		 */
1820 		if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
1821 			np = &nep->ne_defexported;
1822 	}
1823 	return (np);
1824 }
1825 
1826 /*
1827  * perform msync on all vnodes under a mount point.  The mount point must
1828  * be locked.  This code is also responsible for lazy-freeing unreferenced
1829  * vnodes whos VM objects no longer contain pages.
1830  *
1831  * NOTE: MNT_WAIT still skips vnodes in the VXLOCK state.
1832  *
1833  * NOTE: XXX VOP_PUTPAGES and friends requires that the vnode be locked,
1834  * but vnode_pager_putpages() doesn't lock the vnode.  We have to do it
1835  * way up in this high level function.
1836  */
1837 static int vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data);
1838 static int vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data);
1839 
1840 void
1841 vfs_msync(struct mount *mp, int flags)
1842 {
1843 	int vmsc_flags;
1844 
1845 	vmsc_flags = VMSC_GETVP;
1846 	if (flags != MNT_WAIT)
1847 		vmsc_flags |= VMSC_NOWAIT;
1848 	vmntvnodescan(mp, vmsc_flags, vfs_msync_scan1, vfs_msync_scan2,
1849 			(void *)flags);
1850 }
1851 
1852 /*
1853  * scan1 is a fast pre-check.  There could be hundreds of thousands of
1854  * vnodes, we cannot afford to do anything heavy weight until we have a
1855  * fairly good indication that there is work to do.
1856  */
1857 static
1858 int
1859 vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data)
1860 {
1861 	int flags = (int)data;
1862 
1863 	if ((vp->v_flag & VRECLAIMED) == 0) {
1864 		if (vshouldmsync(vp))
1865 			return(0);	/* call scan2 */
1866 		if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
1867 		    (vp->v_flag & VOBJDIRTY) &&
1868 		    (flags == MNT_WAIT || vn_islocked(vp) == 0)) {
1869 			return(0);	/* call scan2 */
1870 		}
1871 	}
1872 
1873 	/*
1874 	 * do not call scan2, continue the loop
1875 	 */
1876 	return(-1);
1877 }
1878 
1879 /*
1880  * This callback is handed a locked vnode.
1881  */
1882 static
1883 int
1884 vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data)
1885 {
1886 	vm_object_t obj;
1887 	int flags = (int)data;
1888 
1889 	if (vp->v_flag & VRECLAIMED)
1890 		return(0);
1891 
1892 	if ((mp->mnt_flag & MNT_RDONLY) == 0 && (vp->v_flag & VOBJDIRTY)) {
1893 		if ((obj = vp->v_object) != NULL) {
1894 			vm_object_page_clean(obj, 0, 0,
1895 			 flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
1896 		}
1897 	}
1898 	return(0);
1899 }
1900 
1901 /*
1902  * Record a process's interest in events which might happen to
1903  * a vnode.  Because poll uses the historic select-style interface
1904  * internally, this routine serves as both the ``check for any
1905  * pending events'' and the ``record my interest in future events''
1906  * functions.  (These are done together, while the lock is held,
1907  * to avoid race conditions.)
1908  */
1909 int
1910 vn_pollrecord(struct vnode *vp, int events)
1911 {
1912 	lwkt_tokref ilock;
1913 
1914 	KKASSERT(curthread->td_proc != NULL);
1915 
1916 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
1917 	if (vp->v_pollinfo.vpi_revents & events) {
1918 		/*
1919 		 * This leaves events we are not interested
1920 		 * in available for the other process which
1921 		 * which presumably had requested them
1922 		 * (otherwise they would never have been
1923 		 * recorded).
1924 		 */
1925 		events &= vp->v_pollinfo.vpi_revents;
1926 		vp->v_pollinfo.vpi_revents &= ~events;
1927 
1928 		lwkt_reltoken(&ilock);
1929 		return events;
1930 	}
1931 	vp->v_pollinfo.vpi_events |= events;
1932 	selrecord(curthread, &vp->v_pollinfo.vpi_selinfo);
1933 	lwkt_reltoken(&ilock);
1934 	return 0;
1935 }
1936 
1937 /*
1938  * Note the occurrence of an event.  If the VN_POLLEVENT macro is used,
1939  * it is possible for us to miss an event due to race conditions, but
1940  * that condition is expected to be rare, so for the moment it is the
1941  * preferred interface.
1942  */
1943 void
1944 vn_pollevent(struct vnode *vp, int events)
1945 {
1946 	lwkt_tokref ilock;
1947 
1948 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
1949 	if (vp->v_pollinfo.vpi_events & events) {
1950 		/*
1951 		 * We clear vpi_events so that we don't
1952 		 * call selwakeup() twice if two events are
1953 		 * posted before the polling process(es) is
1954 		 * awakened.  This also ensures that we take at
1955 		 * most one selwakeup() if the polling process
1956 		 * is no longer interested.  However, it does
1957 		 * mean that only one event can be noticed at
1958 		 * a time.  (Perhaps we should only clear those
1959 		 * event bits which we note?) XXX
1960 		 */
1961 		vp->v_pollinfo.vpi_events = 0;	/* &= ~events ??? */
1962 		vp->v_pollinfo.vpi_revents |= events;
1963 		selwakeup(&vp->v_pollinfo.vpi_selinfo);
1964 	}
1965 	lwkt_reltoken(&ilock);
1966 }
1967 
1968 /*
1969  * Wake up anyone polling on vp because it is being revoked.
1970  * This depends on dead_poll() returning POLLHUP for correct
1971  * behavior.
1972  */
1973 void
1974 vn_pollgone(struct vnode *vp)
1975 {
1976 	lwkt_tokref ilock;
1977 
1978 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
1979 	if (vp->v_pollinfo.vpi_events) {
1980 		vp->v_pollinfo.vpi_events = 0;
1981 		selwakeup(&vp->v_pollinfo.vpi_selinfo);
1982 	}
1983 	lwkt_reltoken(&ilock);
1984 }
1985 
1986 /*
1987  * extract the cdev_t from a VBLK or VCHR.  The vnode must have been opened
1988  * (or v_rdev might be NULL).
1989  */
1990 cdev_t
1991 vn_todev(struct vnode *vp)
1992 {
1993 	if (vp->v_type != VBLK && vp->v_type != VCHR)
1994 		return (NULL);
1995 	KKASSERT(vp->v_rdev != NULL);
1996 	return (vp->v_rdev);
1997 }
1998 
1999 /*
2000  * Check if vnode represents a disk device.  The vnode does not need to be
2001  * opened.
2002  */
2003 int
2004 vn_isdisk(struct vnode *vp, int *errp)
2005 {
2006 	cdev_t dev;
2007 
2008 	if (vp->v_type != VCHR) {
2009 		if (errp != NULL)
2010 			*errp = ENOTBLK;
2011 		return (0);
2012 	}
2013 
2014 	if ((dev = vp->v_rdev) == NULL)
2015 		dev = get_dev(vp->v_umajor, vp->v_uminor);
2016 
2017 	if (dev == NULL) {
2018 		if (errp != NULL)
2019 			*errp = ENXIO;
2020 		return (0);
2021 	}
2022 	if (dev_is_good(dev) == 0) {
2023 		if (errp != NULL)
2024 			*errp = ENXIO;
2025 		return (0);
2026 	}
2027 	if ((dev_dflags(dev) & D_DISK) == 0) {
2028 		if (errp != NULL)
2029 			*errp = ENOTBLK;
2030 		return (0);
2031 	}
2032 	if (errp != NULL)
2033 		*errp = 0;
2034 	return (1);
2035 }
2036 
2037 int
2038 vn_get_namelen(struct vnode *vp, int *namelen)
2039 {
2040 	int error, retval[2];
2041 
2042 	error = VOP_PATHCONF(vp, _PC_NAME_MAX, retval);
2043 	if (error)
2044 		return (error);
2045 	*namelen = *retval;
2046 	return (0);
2047 }
2048 
2049 int
2050 vop_write_dirent(int *error, struct uio *uio, ino_t d_ino, uint8_t d_type,
2051 		uint16_t d_namlen, const char *d_name)
2052 {
2053 	struct dirent *dp;
2054 	size_t len;
2055 
2056 	len = _DIRENT_RECLEN(d_namlen);
2057 	if (len > uio->uio_resid)
2058 		return(1);
2059 
2060 	dp = kmalloc(len, M_TEMP, M_WAITOK | M_ZERO);
2061 
2062 	dp->d_ino = d_ino;
2063 	dp->d_namlen = d_namlen;
2064 	dp->d_type = d_type;
2065 	bcopy(d_name, dp->d_name, d_namlen);
2066 
2067 	*error = uiomove((caddr_t)dp, len, uio);
2068 
2069 	kfree(dp, M_TEMP);
2070 
2071 	return(0);
2072 }
2073 
2074