xref: /dragonfly/sys/kern/vfs_subr.c (revision d9d67b59)
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. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)vfs_subr.c	8.31 (Berkeley) 5/26/95
35  * $FreeBSD: src/sys/kern/vfs_subr.c,v 1.249.2.30 2003/04/04 20:35:57 tegge Exp $
36  */
37 
38 /*
39  * External virtual filesystem routines
40  */
41 #include "opt_ddb.h"
42 #include "opt_inet.h"
43 #include "opt_inet6.h"
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/buf.h>
48 #include <sys/conf.h>
49 #include <sys/dirent.h>
50 #include <sys/eventhandler.h>
51 #include <sys/fcntl.h>
52 #include <sys/file.h>
53 #include <sys/kernel.h>
54 #include <sys/kthread.h>
55 #include <sys/malloc.h>
56 #include <sys/mbuf.h>
57 #include <sys/mount.h>
58 #include <sys/priv.h>
59 #include <sys/proc.h>
60 #include <sys/reboot.h>
61 #include <sys/socket.h>
62 #include <sys/stat.h>
63 #include <sys/sysctl.h>
64 #include <sys/syslog.h>
65 #include <sys/unistd.h>
66 #include <sys/vmmeter.h>
67 #include <sys/vnode.h>
68 
69 #include <machine/limits.h>
70 
71 #include <vm/vm.h>
72 #include <vm/vm_object.h>
73 #include <vm/vm_extern.h>
74 #include <vm/vm_kern.h>
75 #include <vm/pmap.h>
76 #include <vm/vm_map.h>
77 #include <vm/vm_page.h>
78 #include <vm/vm_pager.h>
79 #include <vm/vnode_pager.h>
80 #include <vm/vm_zone.h>
81 
82 #include <sys/buf2.h>
83 #include <sys/thread2.h>
84 #include <sys/sysref2.h>
85 #include <sys/mplock2.h>
86 #include <vm/vm_page2.h>
87 
88 #include <netinet/in.h>
89 
90 static MALLOC_DEFINE(M_NETCRED, "Export Host", "Export host address structure");
91 
92 int numvnodes;
93 SYSCTL_INT(_debug, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0,
94     "Number of vnodes allocated");
95 int verbose_reclaims;
96 SYSCTL_INT(_debug, OID_AUTO, verbose_reclaims, CTLFLAG_RD, &verbose_reclaims, 0,
97     "Output filename of reclaimed vnode(s)");
98 
99 enum vtype iftovt_tab[16] = {
100 	VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
101 	VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
102 };
103 int vttoif_tab[9] = {
104 	0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
105 	S_IFSOCK, S_IFIFO, S_IFMT,
106 };
107 
108 static int reassignbufcalls;
109 SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW, &reassignbufcalls,
110     0, "Number of times buffers have been reassigned to the proper list");
111 
112 static int check_buf_overlap = 2;	/* invasive check */
113 SYSCTL_INT(_vfs, OID_AUTO, check_buf_overlap, CTLFLAG_RW, &check_buf_overlap,
114     0, "Enable overlapping buffer checks");
115 
116 int	nfs_mount_type = -1;
117 static struct lwkt_token spechash_token;
118 struct nfs_public nfs_pub;	/* publicly exported FS */
119 
120 int maxvnodes;
121 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
122 	   &maxvnodes, 0, "Maximum number of vnodes");
123 
124 static struct radix_node_head *vfs_create_addrlist_af(int af,
125 		    struct netexport *nep);
126 static void	vfs_free_addrlist (struct netexport *nep);
127 static int	vfs_free_netcred (struct radix_node *rn, void *w);
128 static void	vfs_free_addrlist_af (struct radix_node_head **prnh);
129 static int	vfs_hang_addrlist (struct mount *mp, struct netexport *nep,
130 	            const struct export_args *argp);
131 
132 int	prtactive = 0;		/* 1 => print out reclaim of active vnodes */
133 
134 /*
135  * Red black tree functions
136  */
137 static int rb_buf_compare(struct buf *b1, struct buf *b2);
138 RB_GENERATE2(buf_rb_tree, buf, b_rbnode, rb_buf_compare, off_t, b_loffset);
139 RB_GENERATE2(buf_rb_hash, buf, b_rbhash, rb_buf_compare, off_t, b_loffset);
140 
141 static int
142 rb_buf_compare(struct buf *b1, struct buf *b2)
143 {
144 	if (b1->b_loffset < b2->b_loffset)
145 		return(-1);
146 	if (b1->b_loffset > b2->b_loffset)
147 		return(1);
148 	return(0);
149 }
150 
151 /*
152  * Initialize the vnode management data structures.
153  *
154  * Called from vfsinit()
155  */
156 void
157 vfs_subr_init(void)
158 {
159 	int factor1;
160 	int factor2;
161 
162 	/*
163 	 * Desiredvnodes is kern.maxvnodes.  We want to scale it
164 	 * according to available system memory but we may also have
165 	 * to limit it based on available KVM, which is capped on 32 bit
166 	 * systems, to ~80K vnodes or so.
167 	 *
168 	 * WARNING!  For machines with 64-256M of ram we have to be sure
169 	 *	     that the default limit scales down well due to HAMMER
170 	 *	     taking up significantly more memory per-vnode vs UFS.
171 	 *	     We want around ~5800 on a 128M machine.
172 	 */
173 	factor1 = 25 * (sizeof(struct vm_object) + sizeof(struct vnode));
174 	factor2 = 30 * (sizeof(struct vm_object) + sizeof(struct vnode));
175 	maxvnodes = imin((int64_t)vmstats.v_page_count * PAGE_SIZE / factor1,
176 			 KvaSize / factor2);
177 	maxvnodes = imax(maxvnodes, maxproc * 8);
178 
179 	lwkt_token_init(&spechash_token, "spechash");
180 }
181 
182 /*
183  * Knob to control the precision of file timestamps:
184  *
185  *   0 = seconds only; nanoseconds zeroed.
186  *   1 = seconds and nanoseconds, accurate within 1/HZ.
187  *   2 = seconds and nanoseconds, truncated to microseconds.
188  * >=3 = seconds and nanoseconds, maximum precision.
189  */
190 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
191 
192 static int timestamp_precision = TSP_SEC;
193 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
194 		&timestamp_precision, 0, "Precision of file timestamps");
195 
196 /*
197  * Get a current timestamp.
198  *
199  * MPSAFE
200  */
201 void
202 vfs_timestamp(struct timespec *tsp)
203 {
204 	struct timeval tv;
205 
206 	switch (timestamp_precision) {
207 	case TSP_SEC:
208 		tsp->tv_sec = time_second;
209 		tsp->tv_nsec = 0;
210 		break;
211 	case TSP_HZ:
212 		getnanotime(tsp);
213 		break;
214 	case TSP_USEC:
215 		microtime(&tv);
216 		TIMEVAL_TO_TIMESPEC(&tv, tsp);
217 		break;
218 	case TSP_NSEC:
219 	default:
220 		nanotime(tsp);
221 		break;
222 	}
223 }
224 
225 /*
226  * Set vnode attributes to VNOVAL
227  */
228 void
229 vattr_null(struct vattr *vap)
230 {
231 	vap->va_type = VNON;
232 	vap->va_size = VNOVAL;
233 	vap->va_bytes = VNOVAL;
234 	vap->va_mode = VNOVAL;
235 	vap->va_nlink = VNOVAL;
236 	vap->va_uid = VNOVAL;
237 	vap->va_gid = VNOVAL;
238 	vap->va_fsid = VNOVAL;
239 	vap->va_fileid = VNOVAL;
240 	vap->va_blocksize = VNOVAL;
241 	vap->va_rmajor = VNOVAL;
242 	vap->va_rminor = VNOVAL;
243 	vap->va_atime.tv_sec = VNOVAL;
244 	vap->va_atime.tv_nsec = VNOVAL;
245 	vap->va_mtime.tv_sec = VNOVAL;
246 	vap->va_mtime.tv_nsec = VNOVAL;
247 	vap->va_ctime.tv_sec = VNOVAL;
248 	vap->va_ctime.tv_nsec = VNOVAL;
249 	vap->va_flags = VNOVAL;
250 	vap->va_gen = VNOVAL;
251 	vap->va_vaflags = 0;
252 	/* va_*_uuid fields are only valid if related flags are set */
253 }
254 
255 /*
256  * Flush out and invalidate all buffers associated with a vnode.
257  *
258  * vp must be locked.
259  */
260 static int vinvalbuf_bp(struct buf *bp, void *data);
261 
262 struct vinvalbuf_bp_info {
263 	struct vnode *vp;
264 	int slptimeo;
265 	int lkflags;
266 	int flags;
267 	int clean;
268 };
269 
270 int
271 vinvalbuf(struct vnode *vp, int flags, int slpflag, int slptimeo)
272 {
273 	struct vinvalbuf_bp_info info;
274 	vm_object_t object;
275 	int error;
276 
277 	lwkt_gettoken(&vp->v_token);
278 
279 	/*
280 	 * If we are being asked to save, call fsync to ensure that the inode
281 	 * is updated.
282 	 */
283 	if (flags & V_SAVE) {
284 		error = bio_track_wait(&vp->v_track_write, slpflag, slptimeo);
285 		if (error)
286 			goto done;
287 		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
288 			if ((error = VOP_FSYNC(vp, MNT_WAIT, 0)) != 0)
289 				goto done;
290 #if 0
291 			/*
292 			 * Dirty bufs may be left or generated via races
293 			 * in circumstances where vinvalbuf() is called on
294 			 * a vnode not undergoing reclamation.   Only
295 			 * panic if we are trying to reclaim the vnode.
296 			 */
297 			if ((vp->v_flag & VRECLAIMED) &&
298 			    (bio_track_active(&vp->v_track_write) ||
299 			    !RB_EMPTY(&vp->v_rbdirty_tree))) {
300 				panic("vinvalbuf: dirty bufs");
301 			}
302 #endif
303 		}
304   	}
305 	info.slptimeo = slptimeo;
306 	info.lkflags = LK_EXCLUSIVE | LK_SLEEPFAIL;
307 	if (slpflag & PCATCH)
308 		info.lkflags |= LK_PCATCH;
309 	info.flags = flags;
310 	info.vp = vp;
311 
312 	/*
313 	 * Flush the buffer cache until nothing is left, wait for all I/O
314 	 * to complete.  At least one pass is required.  We might block
315 	 * in the pip code so we have to re-check.  Order is important.
316 	 */
317 	do {
318 		/*
319 		 * Flush buffer cache
320 		 */
321 		if (!RB_EMPTY(&vp->v_rbclean_tree)) {
322 			info.clean = 1;
323 			error = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
324 					NULL, vinvalbuf_bp, &info);
325 		}
326 		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
327 			info.clean = 0;
328 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
329 					NULL, vinvalbuf_bp, &info);
330 		}
331 
332 		/*
333 		 * Wait for I/O completion.
334 		 */
335 		bio_track_wait(&vp->v_track_write, 0, 0);
336 		if ((object = vp->v_object) != NULL)
337 			refcount_wait(&object->paging_in_progress, "vnvlbx");
338 	} while (bio_track_active(&vp->v_track_write) ||
339 		 !RB_EMPTY(&vp->v_rbclean_tree) ||
340 		 !RB_EMPTY(&vp->v_rbdirty_tree));
341 
342 	/*
343 	 * Destroy the copy in the VM cache, too.
344 	 */
345 	if ((object = vp->v_object) != NULL) {
346 		vm_object_page_remove(object, 0, 0,
347 			(flags & V_SAVE) ? TRUE : FALSE);
348 	}
349 
350 	if (!RB_EMPTY(&vp->v_rbdirty_tree) || !RB_EMPTY(&vp->v_rbclean_tree))
351 		panic("vinvalbuf: flush failed");
352 	if (!RB_EMPTY(&vp->v_rbhash_tree))
353 		panic("vinvalbuf: flush failed, buffers still present");
354 	error = 0;
355 done:
356 	lwkt_reltoken(&vp->v_token);
357 	return (error);
358 }
359 
360 static int
361 vinvalbuf_bp(struct buf *bp, void *data)
362 {
363 	struct vinvalbuf_bp_info *info = data;
364 	int error;
365 
366 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
367 		atomic_add_int(&bp->b_refs, 1);
368 		error = BUF_TIMELOCK(bp, info->lkflags,
369 				     "vinvalbuf", info->slptimeo);
370 		atomic_subtract_int(&bp->b_refs, 1);
371 		if (error == 0) {
372 			BUF_UNLOCK(bp);
373 			error = ENOLCK;
374 		}
375 		if (error == ENOLCK)
376 			return(0);
377 		return (-error);
378 	}
379 	KKASSERT(bp->b_vp == info->vp);
380 
381 	/*
382 	 * Must check clean/dirty status after successfully locking as
383 	 * it may race.
384 	 */
385 	if ((info->clean && (bp->b_flags & B_DELWRI)) ||
386 	    (info->clean == 0 && (bp->b_flags & B_DELWRI) == 0)) {
387 		BUF_UNLOCK(bp);
388 		return(0);
389 	}
390 
391 	/*
392 	 * NOTE:  NO B_LOCKED CHECK.  Also no buf_checkwrite()
393 	 * check.  This code will write out the buffer, period.
394 	 */
395 	bremfree(bp);
396 	if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
397 	    (info->flags & V_SAVE)) {
398 		cluster_awrite(bp);
399 	} else if (info->flags & V_SAVE) {
400 		/*
401 		 * Cannot set B_NOCACHE on a clean buffer as this will
402 		 * destroy the VM backing store which might actually
403 		 * be dirty (and unsynchronized).
404 		 */
405 		bp->b_flags |= (B_INVAL | B_RELBUF);
406 		brelse(bp);
407 	} else {
408 		bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
409 		brelse(bp);
410 	}
411 	return(0);
412 }
413 
414 /*
415  * Truncate a file's buffer and pages to a specified length.  This
416  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
417  * sync activity.
418  *
419  * The vnode must be locked.
420  */
421 static int vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data);
422 static int vtruncbuf_bp_trunc(struct buf *bp, void *data);
423 static int vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data);
424 static int vtruncbuf_bp_metasync(struct buf *bp, void *data);
425 
426 struct vtruncbuf_info {
427 	struct vnode *vp;
428 	off_t	truncloffset;
429 	int	clean;
430 };
431 
432 int
433 vtruncbuf(struct vnode *vp, off_t length, int blksize)
434 {
435 	struct vtruncbuf_info info;
436 	const char *filename;
437 	int count;
438 
439 	/*
440 	 * Round up to the *next* block, then destroy the buffers in question.
441 	 * Since we are only removing some of the buffers we must rely on the
442 	 * scan count to determine whether a loop is necessary.
443 	 */
444 	if ((count = (int)(length % blksize)) != 0)
445 		info.truncloffset = length + (blksize - count);
446 	else
447 		info.truncloffset = length;
448 	info.vp = vp;
449 
450 	lwkt_gettoken(&vp->v_token);
451 	do {
452 		info.clean = 1;
453 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
454 				vtruncbuf_bp_trunc_cmp,
455 				vtruncbuf_bp_trunc, &info);
456 		info.clean = 0;
457 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
458 				vtruncbuf_bp_trunc_cmp,
459 				vtruncbuf_bp_trunc, &info);
460 	} while(count);
461 
462 	/*
463 	 * For safety, fsync any remaining metadata if the file is not being
464 	 * truncated to 0.  Since the metadata does not represent the entire
465 	 * dirty list we have to rely on the hit count to ensure that we get
466 	 * all of it.
467 	 */
468 	if (length > 0) {
469 		do {
470 			count = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
471 					vtruncbuf_bp_metasync_cmp,
472 					vtruncbuf_bp_metasync, &info);
473 		} while (count);
474 	}
475 
476 	/*
477 	 * Clean out any left over VM backing store.
478 	 *
479 	 * It is possible to have in-progress I/O from buffers that were
480 	 * not part of the truncation.  This should not happen if we
481 	 * are truncating to 0-length.
482 	 */
483 	vnode_pager_setsize(vp, length);
484 	bio_track_wait(&vp->v_track_write, 0, 0);
485 
486 	/*
487 	 * Debugging only
488 	 */
489 	spin_lock(&vp->v_spin);
490 	filename = TAILQ_FIRST(&vp->v_namecache) ?
491 		   TAILQ_FIRST(&vp->v_namecache)->nc_name : "?";
492 	spin_unlock(&vp->v_spin);
493 
494 	/*
495 	 * Make sure no buffers were instantiated while we were trying
496 	 * to clean out the remaining VM pages.  This could occur due
497 	 * to busy dirty VM pages being flushed out to disk.
498 	 */
499 	do {
500 		info.clean = 1;
501 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
502 				vtruncbuf_bp_trunc_cmp,
503 				vtruncbuf_bp_trunc, &info);
504 		info.clean = 0;
505 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
506 				vtruncbuf_bp_trunc_cmp,
507 				vtruncbuf_bp_trunc, &info);
508 		if (count) {
509 			kprintf("Warning: vtruncbuf():  Had to re-clean %d "
510 			       "left over buffers in %s\n", count, filename);
511 		}
512 	} while(count);
513 
514 	lwkt_reltoken(&vp->v_token);
515 
516 	return (0);
517 }
518 
519 /*
520  * The callback buffer is beyond the new file EOF and must be destroyed.
521  * Note that the compare function must conform to the RB_SCAN's requirements.
522  */
523 static
524 int
525 vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data)
526 {
527 	struct vtruncbuf_info *info = data;
528 
529 	if (bp->b_loffset >= info->truncloffset)
530 		return(0);
531 	return(-1);
532 }
533 
534 static
535 int
536 vtruncbuf_bp_trunc(struct buf *bp, void *data)
537 {
538 	struct vtruncbuf_info *info = data;
539 
540 	/*
541 	 * Do not try to use a buffer we cannot immediately lock, but sleep
542 	 * anyway to prevent a livelock.  The code will loop until all buffers
543 	 * can be acted upon.
544 	 *
545 	 * We must always revalidate the buffer after locking it to deal
546 	 * with MP races.
547 	 */
548 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
549 		atomic_add_int(&bp->b_refs, 1);
550 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
551 			BUF_UNLOCK(bp);
552 		atomic_subtract_int(&bp->b_refs, 1);
553 	} else if ((info->clean && (bp->b_flags & B_DELWRI)) ||
554 		   (info->clean == 0 && (bp->b_flags & B_DELWRI) == 0) ||
555 		   bp->b_vp != info->vp ||
556 		   vtruncbuf_bp_trunc_cmp(bp, data)) {
557 		BUF_UNLOCK(bp);
558 	} else {
559 		bremfree(bp);
560 		bp->b_flags |= (B_INVAL | B_RELBUF | B_NOCACHE);
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 __unused)
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 vtruncbuf_info *info = data;
583 
584 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
585 		atomic_add_int(&bp->b_refs, 1);
586 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
587 			BUF_UNLOCK(bp);
588 		atomic_subtract_int(&bp->b_refs, 1);
589 	} else if ((bp->b_flags & B_DELWRI) == 0 ||
590 		   bp->b_vp != info->vp ||
591 		   vtruncbuf_bp_metasync_cmp(bp, data)) {
592 		BUF_UNLOCK(bp);
593 	} else {
594 		bremfree(bp);
595 		if (bp->b_vp == info->vp)
596 			bawrite(bp);
597 		else
598 			bwrite(bp);
599 	}
600 	return(1);
601 }
602 
603 /*
604  * vfsync - implements a multipass fsync on a file which understands
605  * dependancies and meta-data.  The passed vnode must be locked.  The
606  * waitfor argument may be MNT_WAIT or MNT_NOWAIT, or MNT_LAZY.
607  *
608  * When fsyncing data asynchronously just do one consolidated pass starting
609  * with the most negative block number.  This may not get all the data due
610  * to dependancies.
611  *
612  * When fsyncing data synchronously do a data pass, then a metadata pass,
613  * then do additional data+metadata passes to try to get all the data out.
614  *
615  * Caller must ref the vnode but does not have to lock it.
616  */
617 static int vfsync_wait_output(struct vnode *vp,
618 			    int (*waitoutput)(struct vnode *, struct thread *));
619 static int vfsync_dummy_cmp(struct buf *bp __unused, void *data __unused);
620 static int vfsync_data_only_cmp(struct buf *bp, void *data);
621 static int vfsync_meta_only_cmp(struct buf *bp, void *data);
622 static int vfsync_lazy_range_cmp(struct buf *bp, void *data);
623 static int vfsync_bp(struct buf *bp, void *data);
624 
625 struct vfsync_info {
626 	struct vnode *vp;
627 	int fastpass;
628 	int synchronous;
629 	int syncdeps;
630 	int lazycount;
631 	int lazylimit;
632 	int skippedbufs;
633 	int (*checkdef)(struct buf *);
634 	int (*cmpfunc)(struct buf *, void *);
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 	lwkt_gettoken(&vp->v_token);
651 
652 	switch(waitfor) {
653 	case MNT_LAZY | MNT_NOWAIT:
654 	case MNT_LAZY:
655 		/*
656 		 * Lazy (filesystem syncer typ) Asynchronous plus limit the
657 		 * number of data (not meta) pages we try to flush to 1MB.
658 		 * A non-zero return means that lazy limit was reached.
659 		 */
660 		info.lazylimit = 1024 * 1024;
661 		info.syncdeps = 1;
662 		info.cmpfunc = vfsync_lazy_range_cmp;
663 		error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
664 				vfsync_lazy_range_cmp, vfsync_bp, &info);
665 		info.cmpfunc = vfsync_meta_only_cmp;
666 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
667 			vfsync_meta_only_cmp, vfsync_bp, &info);
668 		if (error == 0)
669 			vp->v_lazyw = 0;
670 		else if (!RB_EMPTY(&vp->v_rbdirty_tree))
671 			vn_syncer_add(vp, 1);
672 		error = 0;
673 		break;
674 	case MNT_NOWAIT:
675 		/*
676 		 * Asynchronous.  Do a data-only pass and a meta-only pass.
677 		 */
678 		info.syncdeps = 1;
679 		info.cmpfunc = vfsync_data_only_cmp;
680 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
681 			vfsync_bp, &info);
682 		info.cmpfunc = vfsync_meta_only_cmp;
683 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_meta_only_cmp,
684 			vfsync_bp, &info);
685 		error = 0;
686 		break;
687 	default:
688 		/*
689 		 * Synchronous.  Do a data-only pass, then a meta-data+data
690 		 * pass, then additional integrated passes to try to get
691 		 * all the dependancies flushed.
692 		 */
693 		info.cmpfunc = vfsync_data_only_cmp;
694 		info.fastpass = 1;
695 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
696 			vfsync_bp, &info);
697 		info.fastpass = 0;
698 		error = vfsync_wait_output(vp, waitoutput);
699 		if (error == 0) {
700 			info.skippedbufs = 0;
701 			info.cmpfunc = vfsync_dummy_cmp;
702 			RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
703 				vfsync_bp, &info);
704 			error = vfsync_wait_output(vp, waitoutput);
705 			if (info.skippedbufs) {
706 				kprintf("Warning: vfsync skipped %d dirty "
707 					"buf%s in pass2!\n",
708 					info.skippedbufs,
709 					((info.skippedbufs > 1) ? "s" : ""));
710 			}
711 		}
712 		while (error == 0 && passes > 0 &&
713 		       !RB_EMPTY(&vp->v_rbdirty_tree)
714 		) {
715 			info.skippedbufs = 0;
716 			if (--passes == 0) {
717 				info.synchronous = 1;
718 				info.syncdeps = 1;
719 			}
720 			info.cmpfunc = vfsync_dummy_cmp;
721 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
722 					vfsync_bp, &info);
723 			if (error < 0)
724 				error = -error;
725 			info.syncdeps = 1;
726 			if (error == 0)
727 				error = vfsync_wait_output(vp, waitoutput);
728 			if (info.skippedbufs && passes == 0) {
729 				kprintf("Warning: vfsync skipped %d dirty "
730 					"buf%s in final pass!\n",
731 					info.skippedbufs,
732 					((info.skippedbufs > 1) ? "s" : ""));
733 			}
734 		}
735 #if 0
736 		/*
737 		 * This case can occur normally because vnode lock might
738 		 * not be held.
739 		 */
740 		if (!RB_EMPTY(&vp->v_rbdirty_tree))
741 			kprintf("dirty bufs left after final pass\n");
742 #endif
743 		break;
744 	}
745 	lwkt_reltoken(&vp->v_token);
746 
747 	return(error);
748 }
749 
750 static int
751 vfsync_wait_output(struct vnode *vp,
752 		   int (*waitoutput)(struct vnode *, struct thread *))
753 {
754 	int error;
755 
756 	error = bio_track_wait(&vp->v_track_write, 0, 0);
757 	if (waitoutput)
758 		error = waitoutput(vp, curthread);
759 	return(error);
760 }
761 
762 static int
763 vfsync_dummy_cmp(struct buf *bp __unused, void *data __unused)
764 {
765 	return(0);
766 }
767 
768 static int
769 vfsync_data_only_cmp(struct buf *bp, void *data)
770 {
771 	if (bp->b_loffset < 0)
772 		return(-1);
773 	return(0);
774 }
775 
776 static int
777 vfsync_meta_only_cmp(struct buf *bp, void *data)
778 {
779 	if (bp->b_loffset < 0)
780 		return(0);
781 	return(1);
782 }
783 
784 static int
785 vfsync_lazy_range_cmp(struct buf *bp, void *data)
786 {
787 	struct vfsync_info *info = data;
788 
789 	if (bp->b_loffset < info->vp->v_lazyw)
790 		return(-1);
791 	return(0);
792 }
793 
794 static int
795 vfsync_bp(struct buf *bp, void *data)
796 {
797 	struct vfsync_info *info = data;
798 	struct vnode *vp = info->vp;
799 	int error;
800 
801 	if (info->fastpass) {
802 		/*
803 		 * Ignore buffers that we cannot immediately lock.
804 		 */
805 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
806 			if (BUF_TIMELOCK(bp, LK_EXCLUSIVE, "bflst1", 1)) {
807 				++info->skippedbufs;
808 				return(0);
809 			}
810 		}
811 	} else if (info->synchronous == 0) {
812 		/*
813 		 * Normal pass, give the buffer a little time to become
814 		 * available to us.
815 		 */
816 		if (BUF_TIMELOCK(bp, LK_EXCLUSIVE, "bflst2", hz / 10)) {
817 			++info->skippedbufs;
818 			return(0);
819 		}
820 	} else {
821 		/*
822 		 * Synchronous pass, give the buffer a lot of time before
823 		 * giving up.
824 		 */
825 		if (BUF_TIMELOCK(bp, LK_EXCLUSIVE, "bflst3", hz * 10)) {
826 			++info->skippedbufs;
827 			return(0);
828 		}
829 	}
830 
831 	/*
832 	 * We must revalidate the buffer after locking.
833 	 */
834 	if ((bp->b_flags & B_DELWRI) == 0 ||
835 	    bp->b_vp != info->vp ||
836 	    info->cmpfunc(bp, data)) {
837 		BUF_UNLOCK(bp);
838 		return(0);
839 	}
840 
841 	/*
842 	 * If syncdeps is not set we do not try to write buffers which have
843 	 * dependancies.
844 	 */
845 	if (!info->synchronous && info->syncdeps == 0 && info->checkdef(bp)) {
846 		BUF_UNLOCK(bp);
847 		return(0);
848 	}
849 
850 	/*
851 	 * B_NEEDCOMMIT (primarily used by NFS) is a state where the buffer
852 	 * has been written but an additional handshake with the device
853 	 * is required before we can dispose of the buffer.  We have no idea
854 	 * how to do this so we have to skip these buffers.
855 	 */
856 	if (bp->b_flags & B_NEEDCOMMIT) {
857 		BUF_UNLOCK(bp);
858 		return(0);
859 	}
860 
861 	/*
862 	 * Ask bioops if it is ok to sync.  If not the VFS may have
863 	 * set B_LOCKED so we have to cycle the buffer.
864 	 */
865 	if (LIST_FIRST(&bp->b_dep) != NULL && buf_checkwrite(bp)) {
866 		bremfree(bp);
867 		brelse(bp);
868 		return(0);
869 	}
870 
871 	if (info->synchronous) {
872 		/*
873 		 * Synchronous flush.  An error may be returned and will
874 		 * stop the scan.
875 		 */
876 		bremfree(bp);
877 		error = bwrite(bp);
878 	} else {
879 		/*
880 		 * Asynchronous flush.  We use the error return to support
881 		 * MNT_LAZY flushes.
882 		 *
883 		 * In low-memory situations we revert to synchronous
884 		 * operation.  This should theoretically prevent the I/O
885 		 * path from exhausting memory in a non-recoverable way.
886 		 */
887 		vp->v_lazyw = bp->b_loffset;
888 		bremfree(bp);
889 		if (vm_page_count_min(0)) {
890 			/* low memory */
891 			info->lazycount += bp->b_bufsize;
892 			bwrite(bp);
893 		} else {
894 			/* normal */
895 			info->lazycount += cluster_awrite(bp);
896 			waitrunningbufspace();
897 			/*vm_wait_nominal();*/
898 		}
899 		if (info->lazylimit && info->lazycount >= info->lazylimit)
900 			error = 1;
901 		else
902 			error = 0;
903 	}
904 	return(-error);
905 }
906 
907 /*
908  * Associate a buffer with a vnode.
909  *
910  * MPSAFE
911  */
912 int
913 bgetvp(struct vnode *vp, struct buf *bp, int testsize)
914 {
915 	KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));
916 	KKASSERT((bp->b_flags & (B_HASHED|B_DELWRI|B_VNCLEAN|B_VNDIRTY)) == 0);
917 
918 	/*
919 	 * Insert onto list for new vnode.
920 	 */
921 	lwkt_gettoken(&vp->v_token);
922 
923 	if (buf_rb_hash_RB_INSERT(&vp->v_rbhash_tree, bp)) {
924 		lwkt_reltoken(&vp->v_token);
925 		return (EEXIST);
926 	}
927 
928 	/*
929 	 * Diagnostics (mainly for HAMMER debugging).  Check for
930 	 * overlapping buffers.
931 	 */
932 	if (check_buf_overlap) {
933 		struct buf *bx;
934 		bx = buf_rb_hash_RB_PREV(bp);
935 		if (bx) {
936 			if (bx->b_loffset + bx->b_bufsize > bp->b_loffset) {
937 				kprintf("bgetvp: overlapl %016jx/%d %016jx "
938 					"bx %p bp %p\n",
939 					(intmax_t)bx->b_loffset,
940 					bx->b_bufsize,
941 					(intmax_t)bp->b_loffset,
942 					bx, bp);
943 				if (check_buf_overlap > 1)
944 					panic("bgetvp - overlapping buffer");
945 			}
946 		}
947 		bx = buf_rb_hash_RB_NEXT(bp);
948 		if (bx) {
949 			if (bp->b_loffset + testsize > bx->b_loffset) {
950 				kprintf("bgetvp: overlapr %016jx/%d %016jx "
951 					"bp %p bx %p\n",
952 					(intmax_t)bp->b_loffset,
953 					testsize,
954 					(intmax_t)bx->b_loffset,
955 					bp, bx);
956 				if (check_buf_overlap > 1)
957 					panic("bgetvp - overlapping buffer");
958 			}
959 		}
960 	}
961 	bp->b_vp = vp;
962 	bp->b_flags |= B_HASHED;
963 	bp->b_flags |= B_VNCLEAN;
964 	if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp))
965 		panic("reassignbuf: dup lblk/clean vp %p bp %p", vp, bp);
966 	/*vhold(vp);*/
967 	lwkt_reltoken(&vp->v_token);
968 	return(0);
969 }
970 
971 /*
972  * Disassociate a buffer from a vnode.
973  *
974  * MPSAFE
975  */
976 void
977 brelvp(struct buf *bp)
978 {
979 	struct vnode *vp;
980 
981 	KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
982 
983 	/*
984 	 * Delete from old vnode list, if on one.
985 	 */
986 	vp = bp->b_vp;
987 	lwkt_gettoken(&vp->v_token);
988 	if (bp->b_flags & (B_VNDIRTY | B_VNCLEAN)) {
989 		if (bp->b_flags & B_VNDIRTY)
990 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
991 		else
992 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
993 		bp->b_flags &= ~(B_VNDIRTY | B_VNCLEAN);
994 	}
995 	if (bp->b_flags & B_HASHED) {
996 		buf_rb_hash_RB_REMOVE(&vp->v_rbhash_tree, bp);
997 		bp->b_flags &= ~B_HASHED;
998 	}
999 
1000 	/*
1001 	 * Only remove from synclist when no dirty buffers are left AND
1002 	 * the VFS has not flagged the vnode's inode as being dirty.
1003 	 */
1004 	if ((vp->v_flag & (VONWORKLST | VISDIRTY | VOBJDIRTY)) == VONWORKLST &&
1005 	    RB_EMPTY(&vp->v_rbdirty_tree)) {
1006 		vn_syncer_remove(vp, 0);
1007 	}
1008 	bp->b_vp = NULL;
1009 
1010 	lwkt_reltoken(&vp->v_token);
1011 
1012 	/*vdrop(vp);*/
1013 }
1014 
1015 /*
1016  * Reassign the buffer to the proper clean/dirty list based on B_DELWRI.
1017  * This routine is called when the state of the B_DELWRI bit is changed.
1018  *
1019  * Must be called with vp->v_token held.
1020  * MPSAFE
1021  */
1022 void
1023 reassignbuf(struct buf *bp)
1024 {
1025 	struct vnode *vp = bp->b_vp;
1026 	int delay;
1027 
1028 	ASSERT_LWKT_TOKEN_HELD(&vp->v_token);
1029 	++reassignbufcalls;
1030 
1031 	/*
1032 	 * B_PAGING flagged buffers cannot be reassigned because their vp
1033 	 * is not fully linked in.
1034 	 */
1035 	if (bp->b_flags & B_PAGING)
1036 		panic("cannot reassign paging buffer");
1037 
1038 	if (bp->b_flags & B_DELWRI) {
1039 		/*
1040 		 * Move to the dirty list, add the vnode to the worklist
1041 		 */
1042 		if (bp->b_flags & B_VNCLEAN) {
1043 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
1044 			bp->b_flags &= ~B_VNCLEAN;
1045 		}
1046 		if ((bp->b_flags & B_VNDIRTY) == 0) {
1047 			if (buf_rb_tree_RB_INSERT(&vp->v_rbdirty_tree, bp)) {
1048 				panic("reassignbuf: dup lblk vp %p bp %p",
1049 				      vp, bp);
1050 			}
1051 			bp->b_flags |= B_VNDIRTY;
1052 		}
1053 		if ((vp->v_flag & VONWORKLST) == 0) {
1054 			switch (vp->v_type) {
1055 			case VDIR:
1056 				delay = dirdelay;
1057 				break;
1058 			case VCHR:
1059 			case VBLK:
1060 				if (vp->v_rdev &&
1061 				    vp->v_rdev->si_mountpoint != NULL) {
1062 					delay = metadelay;
1063 					break;
1064 				}
1065 				/* fall through */
1066 			default:
1067 				delay = filedelay;
1068 			}
1069 			vn_syncer_add(vp, delay);
1070 		}
1071 	} else {
1072 		/*
1073 		 * Move to the clean list, remove the vnode from the worklist
1074 		 * if no dirty blocks remain.
1075 		 */
1076 		if (bp->b_flags & B_VNDIRTY) {
1077 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
1078 			bp->b_flags &= ~B_VNDIRTY;
1079 		}
1080 		if ((bp->b_flags & B_VNCLEAN) == 0) {
1081 			if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp)) {
1082 				panic("reassignbuf: dup lblk vp %p bp %p",
1083 				      vp, bp);
1084 			}
1085 			bp->b_flags |= B_VNCLEAN;
1086 		}
1087 
1088 		/*
1089 		 * Only remove from synclist when no dirty buffers are left
1090 		 * AND the VFS has not flagged the vnode's inode as being
1091 		 * dirty.
1092 		 */
1093 		if ((vp->v_flag & (VONWORKLST | VISDIRTY | VOBJDIRTY)) ==
1094 		     VONWORKLST &&
1095 		    RB_EMPTY(&vp->v_rbdirty_tree)) {
1096 			vn_syncer_remove(vp, 0);
1097 		}
1098 	}
1099 }
1100 
1101 /*
1102  * Create a vnode for a block device.  Used for mounting the root file
1103  * system.
1104  *
1105  * A vref()'d vnode is returned.
1106  */
1107 extern struct vop_ops *devfs_vnode_dev_vops_p;
1108 int
1109 bdevvp(cdev_t dev, struct vnode **vpp)
1110 {
1111 	struct vnode *vp;
1112 	struct vnode *nvp;
1113 	int error;
1114 
1115 	if (dev == NULL) {
1116 		*vpp = NULLVP;
1117 		return (ENXIO);
1118 	}
1119 	error = getspecialvnode(VT_NON, NULL, &devfs_vnode_dev_vops_p,
1120 				&nvp, 0, 0);
1121 	if (error) {
1122 		*vpp = NULLVP;
1123 		return (error);
1124 	}
1125 	vp = nvp;
1126 	vp->v_type = VCHR;
1127 #if 0
1128 	vp->v_rdev = dev;
1129 #endif
1130 	v_associate_rdev(vp, dev);
1131 	vp->v_umajor = dev->si_umajor;
1132 	vp->v_uminor = dev->si_uminor;
1133 	vx_unlock(vp);
1134 	*vpp = vp;
1135 	return (0);
1136 }
1137 
1138 int
1139 v_associate_rdev(struct vnode *vp, cdev_t dev)
1140 {
1141 	if (dev == NULL)
1142 		return(ENXIO);
1143 	if (dev_is_good(dev) == 0)
1144 		return(ENXIO);
1145 	KKASSERT(vp->v_rdev == NULL);
1146 	vp->v_rdev = reference_dev(dev);
1147 	lwkt_gettoken(&spechash_token);
1148 	SLIST_INSERT_HEAD(&dev->si_hlist, vp, v_cdevnext);
1149 	lwkt_reltoken(&spechash_token);
1150 	return(0);
1151 }
1152 
1153 void
1154 v_release_rdev(struct vnode *vp)
1155 {
1156 	cdev_t dev;
1157 
1158 	if ((dev = vp->v_rdev) != NULL) {
1159 		lwkt_gettoken(&spechash_token);
1160 		SLIST_REMOVE(&dev->si_hlist, vp, vnode, v_cdevnext);
1161 		vp->v_rdev = NULL;
1162 		release_dev(dev);
1163 		lwkt_reltoken(&spechash_token);
1164 	}
1165 }
1166 
1167 /*
1168  * Add a vnode to the alias list hung off the cdev_t.  We only associate
1169  * the device number with the vnode.  The actual device is not associated
1170  * until the vnode is opened (usually in spec_open()), and will be
1171  * disassociated on last close.
1172  */
1173 void
1174 addaliasu(struct vnode *nvp, int x, int y)
1175 {
1176 	if (nvp->v_type != VBLK && nvp->v_type != VCHR)
1177 		panic("addaliasu on non-special vnode");
1178 	nvp->v_umajor = x;
1179 	nvp->v_uminor = y;
1180 }
1181 
1182 /*
1183  * Simple call that a filesystem can make to try to get rid of a
1184  * vnode.  It will fail if anyone is referencing the vnode (including
1185  * the caller).
1186  *
1187  * The filesystem can check whether its in-memory inode structure still
1188  * references the vp on return.
1189  *
1190  * May only be called if the vnode is in a known state (i.e. being prevented
1191  * from being deallocated by some other condition such as a vfs inode hold).
1192  */
1193 void
1194 vclean_unlocked(struct vnode *vp)
1195 {
1196 	vx_get(vp);
1197 	if (VREFCNT(vp) <= 1)
1198 		vgone_vxlocked(vp);
1199 	vx_put(vp);
1200 }
1201 
1202 /*
1203  * Disassociate a vnode from its underlying filesystem.
1204  *
1205  * The vnode must be VX locked and referenced.  In all normal situations
1206  * there are no active references.  If vclean_vxlocked() is called while
1207  * there are active references, the vnode is being ripped out and we have
1208  * to call VOP_CLOSE() as appropriate before we can reclaim it.
1209  */
1210 void
1211 vclean_vxlocked(struct vnode *vp, int flags)
1212 {
1213 	int active;
1214 	int n;
1215 	vm_object_t object;
1216 	struct namecache *ncp;
1217 
1218 	/*
1219 	 * If the vnode has already been reclaimed we have nothing to do.
1220 	 */
1221 	if (vp->v_flag & VRECLAIMED)
1222 		return;
1223 
1224 	/*
1225 	 * Set flag to interlock operation, flag finalization to ensure
1226 	 * that the vnode winds up on the inactive list, and set v_act to 0.
1227 	 */
1228 	vsetflags(vp, VRECLAIMED);
1229 	atomic_set_int(&vp->v_refcnt, VREF_FINALIZE);
1230 	vp->v_act = 0;
1231 
1232 	if (verbose_reclaims) {
1233 		if ((ncp = TAILQ_FIRST(&vp->v_namecache)) != NULL)
1234 			kprintf("Debug: reclaim %p %s\n", vp, ncp->nc_name);
1235 	}
1236 
1237 	/*
1238 	 * Scrap the vfs cache
1239 	 */
1240 	while (cache_inval_vp(vp, 0) != 0) {
1241 		kprintf("Warning: vnode %p clean/cache_resolution "
1242 			"race detected\n", vp);
1243 		tsleep(vp, 0, "vclninv", 2);
1244 	}
1245 
1246 	/*
1247 	 * Check to see if the vnode is in use. If so we have to reference it
1248 	 * before we clean it out so that its count cannot fall to zero and
1249 	 * generate a race against ourselves to recycle it.
1250 	 */
1251 	active = (VREFCNT(vp) > 0);
1252 
1253 	/*
1254 	 * Clean out any buffers associated with the vnode and destroy its
1255 	 * object, if it has one.
1256 	 */
1257 	vinvalbuf(vp, V_SAVE, 0, 0);
1258 	KKASSERT(lockcountnb(&vp->v_lock) == 1);
1259 
1260 	/*
1261 	 * If purging an active vnode (typically during a forced unmount
1262 	 * or reboot), it must be closed and deactivated before being
1263 	 * reclaimed.  This isn't really all that safe, but what can
1264 	 * we do? XXX.
1265 	 *
1266 	 * Note that neither of these routines unlocks the vnode.
1267 	 */
1268 	if (active && (flags & DOCLOSE)) {
1269 		while ((n = vp->v_opencount) != 0) {
1270 			if (vp->v_writecount)
1271 				VOP_CLOSE(vp, FWRITE|FNONBLOCK, NULL);
1272 			else
1273 				VOP_CLOSE(vp, FNONBLOCK, NULL);
1274 			if (vp->v_opencount == n) {
1275 				kprintf("Warning: unable to force-close"
1276 				       " vnode %p\n", vp);
1277 				break;
1278 			}
1279 		}
1280 	}
1281 
1282 	/*
1283 	 * If the vnode has not been deactivated, deactivated it.  Deactivation
1284 	 * can create new buffers and VM pages so we have to call vinvalbuf()
1285 	 * again to make sure they all get flushed.
1286 	 *
1287 	 * This can occur if a file with a link count of 0 needs to be
1288 	 * truncated.
1289 	 *
1290 	 * If the vnode is already dead don't try to deactivate it.
1291 	 */
1292 	if ((vp->v_flag & VINACTIVE) == 0) {
1293 		vsetflags(vp, VINACTIVE);
1294 		if (vp->v_mount)
1295 			VOP_INACTIVE(vp);
1296 		vinvalbuf(vp, V_SAVE, 0, 0);
1297 	}
1298 	KKASSERT(lockcountnb(&vp->v_lock) == 1);
1299 
1300 	/*
1301 	 * If the vnode has an object, destroy it.
1302 	 */
1303 	while ((object = vp->v_object) != NULL) {
1304 		vm_object_hold(object);
1305 		if (object == vp->v_object)
1306 			break;
1307 		vm_object_drop(object);
1308 	}
1309 
1310 	if (object != NULL) {
1311 		if (object->ref_count == 0) {
1312 			if ((object->flags & OBJ_DEAD) == 0)
1313 				vm_object_terminate(object);
1314 			vm_object_drop(object);
1315 			vclrflags(vp, VOBJBUF);
1316 		} else {
1317 			vm_pager_deallocate(object);
1318 			vclrflags(vp, VOBJBUF);
1319 			vm_object_drop(object);
1320 		}
1321 	}
1322 	KKASSERT((vp->v_flag & VOBJBUF) == 0);
1323 
1324 	/*
1325 	 * Reclaim the vnode if not already dead.
1326 	 */
1327 	if (vp->v_mount && VOP_RECLAIM(vp))
1328 		panic("vclean: cannot reclaim");
1329 
1330 	/*
1331 	 * Done with purge, notify sleepers of the grim news.
1332 	 */
1333 	vp->v_ops = &dead_vnode_vops_p;
1334 	vn_gone(vp);
1335 	vp->v_tag = VT_NON;
1336 
1337 	/*
1338 	 * If we are destroying an active vnode, reactivate it now that
1339 	 * we have reassociated it with deadfs.  This prevents the system
1340 	 * from crashing on the vnode due to it being unexpectedly marked
1341 	 * as inactive or reclaimed.
1342 	 */
1343 	if (active && (flags & DOCLOSE)) {
1344 		vclrflags(vp, VINACTIVE | VRECLAIMED);
1345 	}
1346 }
1347 
1348 /*
1349  * Eliminate all activity associated with the requested vnode
1350  * and with all vnodes aliased to the requested vnode.
1351  *
1352  * The vnode must be referenced but should not be locked.
1353  */
1354 int
1355 vrevoke(struct vnode *vp, struct ucred *cred)
1356 {
1357 	struct vnode *vq;
1358 	struct vnode *vqn;
1359 	cdev_t dev;
1360 	int error;
1361 
1362 	/*
1363 	 * If the vnode has a device association, scrap all vnodes associated
1364 	 * with the device.  Don't let the device disappear on us while we
1365 	 * are scrapping the vnodes.
1366 	 *
1367 	 * The passed vp will probably show up in the list, do not VX lock
1368 	 * it twice!
1369 	 *
1370 	 * Releasing the vnode's rdev here can mess up specfs's call to
1371 	 * device close, so don't do it.  The vnode has been disassociated
1372 	 * and the device will be closed after the last ref on the related
1373 	 * fp goes away (if not still open by e.g. the kernel).
1374 	 */
1375 	if (vp->v_type != VCHR) {
1376 		error = fdrevoke(vp, DTYPE_VNODE, cred);
1377 		return (error);
1378 	}
1379 	if ((dev = vp->v_rdev) == NULL) {
1380 		return(0);
1381 	}
1382 	reference_dev(dev);
1383 	lwkt_gettoken(&spechash_token);
1384 
1385 restart:
1386 	vqn = SLIST_FIRST(&dev->si_hlist);
1387 	if (vqn)
1388 		vhold(vqn);
1389 	while ((vq = vqn) != NULL) {
1390 		if (VREFCNT(vq) > 0) {
1391 			vref(vq);
1392 			fdrevoke(vq, DTYPE_VNODE, cred);
1393 			/*v_release_rdev(vq);*/
1394 			vrele(vq);
1395 			if (vq->v_rdev != dev) {
1396 				vdrop(vq);
1397 				goto restart;
1398 			}
1399 		}
1400 		vqn = SLIST_NEXT(vq, v_cdevnext);
1401 		if (vqn)
1402 			vhold(vqn);
1403 		vdrop(vq);
1404 	}
1405 	lwkt_reltoken(&spechash_token);
1406 	dev_drevoke(dev);
1407 	release_dev(dev);
1408 	return (0);
1409 }
1410 
1411 /*
1412  * This is called when the object underlying a vnode is being destroyed,
1413  * such as in a remove().  Try to recycle the vnode immediately if the
1414  * only active reference is our reference.
1415  *
1416  * Directory vnodes in the namecache with children cannot be immediately
1417  * recycled because numerous VOP_N*() ops require them to be stable.
1418  *
1419  * To avoid recursive recycling from VOP_INACTIVE implemenetations this
1420  * function is a NOP if VRECLAIMED is already set.
1421  */
1422 int
1423 vrecycle(struct vnode *vp)
1424 {
1425 	if (VREFCNT(vp) <= 1 && (vp->v_flag & VRECLAIMED) == 0) {
1426 		if (cache_inval_vp_nonblock(vp))
1427 			return(0);
1428 		vgone_vxlocked(vp);
1429 		return (1);
1430 	}
1431 	return (0);
1432 }
1433 
1434 /*
1435  * Return the maximum I/O size allowed for strategy calls on VP.
1436  *
1437  * If vp is VCHR or VBLK we dive the device, otherwise we use
1438  * the vp's mount info.
1439  *
1440  * The returned value is clamped at MAXPHYS as most callers cannot use
1441  * buffers larger than that size.
1442  */
1443 int
1444 vmaxiosize(struct vnode *vp)
1445 {
1446 	int maxiosize;
1447 
1448 	if (vp->v_type == VBLK || vp->v_type == VCHR)
1449 		maxiosize = vp->v_rdev->si_iosize_max;
1450 	else
1451 		maxiosize = vp->v_mount->mnt_iosize_max;
1452 
1453 	if (maxiosize > MAXPHYS)
1454 		maxiosize = MAXPHYS;
1455 	return (maxiosize);
1456 }
1457 
1458 /*
1459  * Eliminate all activity associated with a vnode in preparation for
1460  * destruction.
1461  *
1462  * The vnode must be VX locked and refd and will remain VX locked and refd
1463  * on return.  This routine may be called with the vnode in any state, as
1464  * long as it is VX locked.  The vnode will be cleaned out and marked
1465  * VRECLAIMED but will not actually be reused until all existing refs and
1466  * holds go away.
1467  *
1468  * NOTE: This routine may be called on a vnode which has not yet been
1469  * already been deactivated (VOP_INACTIVE), or on a vnode which has
1470  * already been reclaimed.
1471  *
1472  * This routine is not responsible for placing us back on the freelist.
1473  * Instead, it happens automatically when the caller releases the VX lock
1474  * (assuming there aren't any other references).
1475  */
1476 void
1477 vgone_vxlocked(struct vnode *vp)
1478 {
1479 	/*
1480 	 * assert that the VX lock is held.  This is an absolute requirement
1481 	 * now for vgone_vxlocked() to be called.
1482 	 */
1483 	KKASSERT(lockcountnb(&vp->v_lock) == 1);
1484 
1485 	/*
1486 	 * Clean out the filesystem specific data and set the VRECLAIMED
1487 	 * bit.  Also deactivate the vnode if necessary.
1488 	 *
1489 	 * The vnode should have automatically been removed from the syncer
1490 	 * list as syncer/dirty flags cleared during the cleaning.
1491 	 */
1492 	vclean_vxlocked(vp, DOCLOSE);
1493 
1494 	/*
1495 	 * Normally panic if the vnode is still dirty, unless we are doing
1496 	 * a forced unmount (tmpfs typically).
1497 	 */
1498 	if (vp->v_flag & VONWORKLST) {
1499 		if (vp->v_mount->mnt_kern_flag & MNTK_UNMOUNTF) {
1500 			/* force removal */
1501 			vn_syncer_remove(vp, 1);
1502 		} else {
1503 			panic("vp %p still dirty in vgone after flush", vp);
1504 		}
1505 	}
1506 
1507 	/*
1508 	 * Delete from old mount point vnode list, if on one.
1509 	 */
1510 	if (vp->v_mount != NULL) {
1511 		KKASSERT(vp->v_data == NULL);
1512 		insmntque(vp, NULL);
1513 	}
1514 
1515 	/*
1516 	 * If special device, remove it from special device alias list
1517 	 * if it is on one.  This should normally only occur if a vnode is
1518 	 * being revoked as the device should otherwise have been released
1519 	 * naturally.
1520 	 */
1521 	if ((vp->v_type == VBLK || vp->v_type == VCHR) && vp->v_rdev != NULL) {
1522 		v_release_rdev(vp);
1523 	}
1524 
1525 	/*
1526 	 * Set us to VBAD
1527 	 */
1528 	vp->v_type = VBAD;
1529 }
1530 
1531 /*
1532  * Lookup a vnode by device number.
1533  *
1534  * Returns non-zero and *vpp set to a vref'd vnode on success.
1535  * Returns zero on failure.
1536  */
1537 int
1538 vfinddev(cdev_t dev, enum vtype type, struct vnode **vpp)
1539 {
1540 	struct vnode *vp;
1541 
1542 	lwkt_gettoken(&spechash_token);
1543 	SLIST_FOREACH(vp, &dev->si_hlist, v_cdevnext) {
1544 		if (type == vp->v_type) {
1545 			*vpp = vp;
1546 			vref(vp);
1547 			lwkt_reltoken(&spechash_token);
1548 			return (1);
1549 		}
1550 	}
1551 	lwkt_reltoken(&spechash_token);
1552 	return (0);
1553 }
1554 
1555 /*
1556  * Calculate the total number of references to a special device.  This
1557  * routine may only be called for VBLK and VCHR vnodes since v_rdev is
1558  * an overloaded field.  Since udev2dev can now return NULL, we have
1559  * to check for a NULL v_rdev.
1560  */
1561 int
1562 count_dev(cdev_t dev)
1563 {
1564 	struct vnode *vp;
1565 	int count = 0;
1566 
1567 	if (SLIST_FIRST(&dev->si_hlist)) {
1568 		lwkt_gettoken(&spechash_token);
1569 		SLIST_FOREACH(vp, &dev->si_hlist, v_cdevnext) {
1570 			count += vp->v_opencount;
1571 		}
1572 		lwkt_reltoken(&spechash_token);
1573 	}
1574 	return(count);
1575 }
1576 
1577 int
1578 vcount(struct vnode *vp)
1579 {
1580 	if (vp->v_rdev == NULL)
1581 		return(0);
1582 	return(count_dev(vp->v_rdev));
1583 }
1584 
1585 /*
1586  * Initialize VMIO for a vnode.  This routine MUST be called before a
1587  * VFS can issue buffer cache ops on a vnode.  It is typically called
1588  * when a vnode is initialized from its inode.
1589  */
1590 int
1591 vinitvmio(struct vnode *vp, off_t filesize, int blksize, int boff)
1592 {
1593 	vm_object_t object;
1594 	int error = 0;
1595 
1596 	object = vp->v_object;
1597 	if (object) {
1598 		vm_object_hold(object);
1599 		KKASSERT(vp->v_object == object);
1600 	}
1601 
1602 	if (object == NULL) {
1603 		object = vnode_pager_alloc(vp, filesize, 0, 0, blksize, boff);
1604 
1605 		/*
1606 		 * Dereference the reference we just created.  This assumes
1607 		 * that the object is associated with the vp.  Allow it to
1608 		 * have zero refs.  It cannot be destroyed as long as it
1609 		 * is associated with the vnode.
1610 		 */
1611 		vm_object_hold(object);
1612 		atomic_add_int(&object->ref_count, -1);
1613 		vrele(vp);
1614 	} else {
1615 		KKASSERT((object->flags & OBJ_DEAD) == 0);
1616 	}
1617 	KASSERT(vp->v_object != NULL, ("vinitvmio: NULL object"));
1618 	vsetflags(vp, VOBJBUF);
1619 	vm_object_drop(object);
1620 
1621 	return (error);
1622 }
1623 
1624 
1625 /*
1626  * Print out a description of a vnode.
1627  */
1628 static char *typename[] =
1629 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
1630 
1631 void
1632 vprint(char *label, struct vnode *vp)
1633 {
1634 	char buf[96];
1635 
1636 	if (label != NULL)
1637 		kprintf("%s: %p: ", label, (void *)vp);
1638 	else
1639 		kprintf("%p: ", (void *)vp);
1640 	kprintf("type %s, refcnt %08x, writecount %d, holdcnt %d,",
1641 		typename[vp->v_type],
1642 		vp->v_refcnt, vp->v_writecount, vp->v_auxrefs);
1643 	buf[0] = '\0';
1644 	if (vp->v_flag & VROOT)
1645 		strcat(buf, "|VROOT");
1646 	if (vp->v_flag & VPFSROOT)
1647 		strcat(buf, "|VPFSROOT");
1648 	if (vp->v_flag & VTEXT)
1649 		strcat(buf, "|VTEXT");
1650 	if (vp->v_flag & VSYSTEM)
1651 		strcat(buf, "|VSYSTEM");
1652 	if (vp->v_flag & VOBJBUF)
1653 		strcat(buf, "|VOBJBUF");
1654 	if (buf[0] != '\0')
1655 		kprintf(" flags (%s)", &buf[1]);
1656 	if (vp->v_data == NULL) {
1657 		kprintf("\n");
1658 	} else {
1659 		kprintf("\n\t");
1660 		VOP_PRINT(vp);
1661 	}
1662 }
1663 
1664 /*
1665  * Do the usual access checking.
1666  * file_mode, uid and gid are from the vnode in question,
1667  * while acc_mode and cred are from the VOP_ACCESS parameter list
1668  */
1669 int
1670 vaccess(enum vtype type, mode_t file_mode, uid_t uid, gid_t gid,
1671     mode_t acc_mode, struct ucred *cred)
1672 {
1673 	mode_t mask;
1674 	int ismember;
1675 
1676 	/*
1677 	 * Super-user always gets read/write access, but execute access depends
1678 	 * on at least one execute bit being set.
1679 	 */
1680 	if (priv_check_cred(cred, PRIV_ROOT, 0) == 0) {
1681 		if ((acc_mode & VEXEC) && type != VDIR &&
1682 		    (file_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)
1683 			return (EACCES);
1684 		return (0);
1685 	}
1686 
1687 	mask = 0;
1688 
1689 	/* Otherwise, check the owner. */
1690 	if (cred->cr_uid == uid) {
1691 		if (acc_mode & VEXEC)
1692 			mask |= S_IXUSR;
1693 		if (acc_mode & VREAD)
1694 			mask |= S_IRUSR;
1695 		if (acc_mode & VWRITE)
1696 			mask |= S_IWUSR;
1697 		return ((file_mode & mask) == mask ? 0 : EACCES);
1698 	}
1699 
1700 	/* Otherwise, check the groups. */
1701 	ismember = groupmember(gid, cred);
1702 	if (cred->cr_svgid == gid || ismember) {
1703 		if (acc_mode & VEXEC)
1704 			mask |= S_IXGRP;
1705 		if (acc_mode & VREAD)
1706 			mask |= S_IRGRP;
1707 		if (acc_mode & VWRITE)
1708 			mask |= S_IWGRP;
1709 		return ((file_mode & mask) == mask ? 0 : EACCES);
1710 	}
1711 
1712 	/* Otherwise, check everyone else. */
1713 	if (acc_mode & VEXEC)
1714 		mask |= S_IXOTH;
1715 	if (acc_mode & VREAD)
1716 		mask |= S_IROTH;
1717 	if (acc_mode & VWRITE)
1718 		mask |= S_IWOTH;
1719 	return ((file_mode & mask) == mask ? 0 : EACCES);
1720 }
1721 
1722 #ifdef DDB
1723 #include <ddb/ddb.h>
1724 
1725 static int db_show_locked_vnodes(struct mount *mp, void *data);
1726 
1727 /*
1728  * List all of the locked vnodes in the system.
1729  * Called when debugging the kernel.
1730  */
1731 DB_SHOW_COMMAND(lockedvnodes, lockedvnodes)
1732 {
1733 	kprintf("Locked vnodes\n");
1734 	mountlist_scan(db_show_locked_vnodes, NULL,
1735 			MNTSCAN_FORWARD|MNTSCAN_NOBUSY);
1736 }
1737 
1738 static int
1739 db_show_locked_vnodes(struct mount *mp, void *data __unused)
1740 {
1741 	struct vnode *vp;
1742 
1743 	TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
1744 		if (vn_islocked(vp))
1745 			vprint(NULL, vp);
1746 	}
1747 	return(0);
1748 }
1749 #endif
1750 
1751 /*
1752  * Top level filesystem related information gathering.
1753  */
1754 static int	sysctl_ovfs_conf (SYSCTL_HANDLER_ARGS);
1755 
1756 static int
1757 vfs_sysctl(SYSCTL_HANDLER_ARGS)
1758 {
1759 	int *name = (int *)arg1 - 1;	/* XXX */
1760 	u_int namelen = arg2 + 1;	/* XXX */
1761 	struct vfsconf *vfsp;
1762 	int maxtypenum;
1763 
1764 #if 1 || defined(COMPAT_PRELITE2)
1765 	/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
1766 	if (namelen == 1)
1767 		return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
1768 #endif
1769 
1770 #ifdef notyet
1771 	/* all sysctl names at this level are at least name and field */
1772 	if (namelen < 2)
1773 		return (ENOTDIR);		/* overloaded */
1774 	if (name[0] != VFS_GENERIC) {
1775 		vfsp = vfsconf_find_by_typenum(name[0]);
1776 		if (vfsp == NULL)
1777 			return (EOPNOTSUPP);
1778 		return ((*vfsp->vfc_vfsops->vfs_sysctl)(&name[1], namelen - 1,
1779 		    oldp, oldlenp, newp, newlen, p));
1780 	}
1781 #endif
1782 	switch (name[1]) {
1783 	case VFS_MAXTYPENUM:
1784 		if (namelen != 2)
1785 			return (ENOTDIR);
1786 		maxtypenum = vfsconf_get_maxtypenum();
1787 		return (SYSCTL_OUT(req, &maxtypenum, sizeof(maxtypenum)));
1788 	case VFS_CONF:
1789 		if (namelen != 3)
1790 			return (ENOTDIR);	/* overloaded */
1791 		vfsp = vfsconf_find_by_typenum(name[2]);
1792 		if (vfsp == NULL)
1793 			return (EOPNOTSUPP);
1794 		return (SYSCTL_OUT(req, vfsp, sizeof *vfsp));
1795 	}
1796 	return (EOPNOTSUPP);
1797 }
1798 
1799 SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD, vfs_sysctl,
1800 	"Generic filesystem");
1801 
1802 #if 1 || defined(COMPAT_PRELITE2)
1803 
1804 static int
1805 sysctl_ovfs_conf_iter(struct vfsconf *vfsp, void *data)
1806 {
1807 	int error;
1808 	struct ovfsconf ovfs;
1809 	struct sysctl_req *req = (struct sysctl_req*) data;
1810 
1811 	bzero(&ovfs, sizeof(ovfs));
1812 	ovfs.vfc_vfsops = vfsp->vfc_vfsops;	/* XXX used as flag */
1813 	strcpy(ovfs.vfc_name, vfsp->vfc_name);
1814 	ovfs.vfc_index = vfsp->vfc_typenum;
1815 	ovfs.vfc_refcount = vfsp->vfc_refcount;
1816 	ovfs.vfc_flags = vfsp->vfc_flags;
1817 	error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
1818 	if (error)
1819 		return error; /* abort iteration with error code */
1820 	else
1821 		return 0; /* continue iterating with next element */
1822 }
1823 
1824 static int
1825 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
1826 {
1827 	return vfsconf_each(sysctl_ovfs_conf_iter, (void*)req);
1828 }
1829 
1830 #endif /* 1 || COMPAT_PRELITE2 */
1831 
1832 /*
1833  * Check to see if a filesystem is mounted on a block device.
1834  */
1835 int
1836 vfs_mountedon(struct vnode *vp)
1837 {
1838 	cdev_t dev;
1839 
1840 	if ((dev = vp->v_rdev) == NULL) {
1841 /*		if (vp->v_type != VBLK)
1842 			dev = get_dev(vp->v_uminor, vp->v_umajor); */
1843 	}
1844 	if (dev != NULL && dev->si_mountpoint)
1845 		return (EBUSY);
1846 	return (0);
1847 }
1848 
1849 /*
1850  * Unmount all filesystems. The list is traversed in reverse order
1851  * of mounting to avoid dependencies.
1852  *
1853  * We want the umountall to be able to break out of its loop if a
1854  * failure occurs, after scanning all possible mounts, so the callback
1855  * returns 0 on error.
1856  *
1857  * NOTE: Do not call mountlist_remove(mp) on error any more, this will
1858  *	 confuse mountlist_scan()'s unbusy check.
1859  */
1860 static int vfs_umountall_callback(struct mount *mp, void *data);
1861 
1862 void
1863 vfs_unmountall(void)
1864 {
1865 	int count;
1866 
1867 	do {
1868 		count = mountlist_scan(vfs_umountall_callback,
1869 					NULL, MNTSCAN_REVERSE|MNTSCAN_NOBUSY);
1870 	} while (count);
1871 }
1872 
1873 static
1874 int
1875 vfs_umountall_callback(struct mount *mp, void *data)
1876 {
1877 	int error;
1878 
1879 	error = dounmount(mp, MNT_FORCE);
1880 	if (error) {
1881 		kprintf("unmount of filesystem mounted from %s failed (",
1882 			mp->mnt_stat.f_mntfromname);
1883 		if (error == EBUSY)
1884 			kprintf("BUSY)\n");
1885 		else
1886 			kprintf("%d)\n", error);
1887 		return 0;
1888 	} else {
1889 		return 1;
1890 	}
1891 }
1892 
1893 /*
1894  * Checks the mount flags for parameter mp and put the names comma-separated
1895  * into a string buffer buf with a size limit specified by len.
1896  *
1897  * It returns the number of bytes written into buf, and (*errorp) will be
1898  * set to 0, EINVAL (if passed length is 0), or ENOSPC (supplied buffer was
1899  * not large enough).  The buffer will be 0-terminated if len was not 0.
1900  */
1901 size_t
1902 vfs_flagstostr(int flags, const struct mountctl_opt *optp,
1903 	       char *buf, size_t len, int *errorp)
1904 {
1905 	static const struct mountctl_opt optnames[] = {
1906 		{ MNT_RDONLY,           "read-only" },
1907 		{ MNT_SYNCHRONOUS,      "synchronous" },
1908 		{ MNT_NOEXEC,           "noexec" },
1909 		{ MNT_NOSUID,           "nosuid" },
1910 		{ MNT_NODEV,            "nodev" },
1911 		{ MNT_AUTOMOUNTED,      "automounted" },
1912 		{ MNT_ASYNC,            "asynchronous" },
1913 		{ MNT_SUIDDIR,          "suiddir" },
1914 		{ MNT_SOFTDEP,          "soft-updates" },
1915 		{ MNT_NOSYMFOLLOW,      "nosymfollow" },
1916 		{ MNT_TRIM,             "trim" },
1917 		{ MNT_NOATIME,          "noatime" },
1918 		{ MNT_NOCLUSTERR,       "noclusterr" },
1919 		{ MNT_NOCLUSTERW,       "noclusterw" },
1920 		{ MNT_EXRDONLY,         "NFS read-only" },
1921 		{ MNT_EXPORTED,         "NFS exported" },
1922 		/* Remaining NFS flags could come here */
1923 		{ MNT_LOCAL,            "local" },
1924 		{ MNT_QUOTA,            "with-quotas" },
1925 		/* { MNT_ROOTFS,           "rootfs" }, */
1926 		/* { MNT_IGNORE,           "ignore" }, */
1927 		{ 0,			NULL}
1928 	};
1929 	int bwritten;
1930 	int bleft;
1931 	int optlen;
1932 	int actsize;
1933 
1934 	*errorp = 0;
1935 	bwritten = 0;
1936 	bleft = len - 1;	/* leave room for trailing \0 */
1937 
1938 	/*
1939 	 * Checks the size of the string. If it contains
1940 	 * any data, then we will append the new flags to
1941 	 * it.
1942 	 */
1943 	actsize = strlen(buf);
1944 	if (actsize > 0)
1945 		buf += actsize;
1946 
1947 	/* Default flags if no flags passed */
1948 	if (optp == NULL)
1949 		optp = optnames;
1950 
1951 	if (bleft < 0) {	/* degenerate case, 0-length buffer */
1952 		*errorp = EINVAL;
1953 		return(0);
1954 	}
1955 
1956 	for (; flags && optp->o_opt; ++optp) {
1957 		if ((flags & optp->o_opt) == 0)
1958 			continue;
1959 		optlen = strlen(optp->o_name);
1960 		if (bwritten || actsize > 0) {
1961 			if (bleft < 2) {
1962 				*errorp = ENOSPC;
1963 				break;
1964 			}
1965 			buf[bwritten++] = ',';
1966 			buf[bwritten++] = ' ';
1967 			bleft -= 2;
1968 		}
1969 		if (bleft < optlen) {
1970 			*errorp = ENOSPC;
1971 			break;
1972 		}
1973 		bcopy(optp->o_name, buf + bwritten, optlen);
1974 		bwritten += optlen;
1975 		bleft -= optlen;
1976 		flags &= ~optp->o_opt;
1977 	}
1978 
1979 	/*
1980 	 * Space already reserved for trailing \0
1981 	 */
1982 	buf[bwritten] = 0;
1983 	return (bwritten);
1984 }
1985 
1986 /*
1987  * Build hash lists of net addresses and hang them off the mount point.
1988  * Called by ufs_mount() to set up the lists of export addresses.
1989  */
1990 static int
1991 vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
1992 		const struct export_args *argp)
1993 {
1994 	struct netcred *np;
1995 	struct radix_node_head *rnh;
1996 	int i;
1997 	struct radix_node *rn;
1998 	struct sockaddr *saddr, *smask = NULL;
1999 	int error;
2000 
2001 	if (argp->ex_addrlen == 0) {
2002 		if (mp->mnt_flag & MNT_DEFEXPORTED)
2003 			return (EPERM);
2004 		np = &nep->ne_defexported;
2005 		np->netc_exflags = argp->ex_flags;
2006 		np->netc_anon = argp->ex_anon;
2007 		np->netc_anon.cr_ref = 1;
2008 		mp->mnt_flag |= MNT_DEFEXPORTED;
2009 		return (0);
2010 	}
2011 
2012 	if (argp->ex_addrlen < 0 || argp->ex_addrlen > MLEN)
2013 		return (EINVAL);
2014 	if (argp->ex_masklen < 0 || argp->ex_masklen > MLEN)
2015 		return (EINVAL);
2016 
2017 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
2018 	np = (struct netcred *)kmalloc(i, M_NETCRED, M_WAITOK | M_ZERO);
2019 	saddr = (struct sockaddr *) (np + 1);
2020 	if ((error = copyin(argp->ex_addr, (caddr_t) saddr, argp->ex_addrlen)))
2021 		goto out;
2022 	if (saddr->sa_len > argp->ex_addrlen)
2023 		saddr->sa_len = argp->ex_addrlen;
2024 	if (argp->ex_masklen) {
2025 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
2026 		error = copyin(argp->ex_mask, (caddr_t)smask, argp->ex_masklen);
2027 		if (error)
2028 			goto out;
2029 		if (smask->sa_len > argp->ex_masklen)
2030 			smask->sa_len = argp->ex_masklen;
2031 	}
2032 	NE_LOCK(nep);
2033 	if (nep->ne_maskhead == NULL) {
2034 		if (!rn_inithead((void **)&nep->ne_maskhead, NULL, 0)) {
2035 			error = ENOBUFS;
2036 			goto out;
2037 		}
2038 	}
2039 	if ((rnh = vfs_create_addrlist_af(saddr->sa_family, nep)) == NULL) {
2040 		error = ENOBUFS;
2041 		goto out;
2042 	}
2043 	rn = (*rnh->rnh_addaddr)((char *)saddr, (char *)smask, rnh,
2044 				 np->netc_rnodes);
2045 	NE_UNLOCK(nep);
2046 	if (rn == NULL || np != (struct netcred *)rn) {	/* already exists */
2047 		error = EPERM;
2048 		goto out;
2049 	}
2050 	np->netc_exflags = argp->ex_flags;
2051 	np->netc_anon = argp->ex_anon;
2052 	np->netc_anon.cr_ref = 1;
2053 	return (0);
2054 
2055 out:
2056 	kfree(np, M_NETCRED);
2057 	return (error);
2058 }
2059 
2060 /*
2061  * Free netcred structures installed in the netexport
2062  */
2063 static int
2064 vfs_free_netcred(struct radix_node *rn, void *w)
2065 {
2066 	struct radix_node_head *rnh = (struct radix_node_head *)w;
2067 
2068 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
2069 	kfree(rn, M_NETCRED);
2070 
2071 	return (0);
2072 }
2073 
2074 /*
2075  * callback to free an element of the mask table installed in the
2076  * netexport.  These may be created indirectly and are not netcred
2077  * structures.
2078  */
2079 static int
2080 vfs_free_netcred_mask(struct radix_node *rn, void *w)
2081 {
2082 	struct radix_node_head *rnh = (struct radix_node_head *)w;
2083 
2084 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
2085 	kfree(rn, M_RTABLE);
2086 
2087 	return (0);
2088 }
2089 
2090 static struct radix_node_head *
2091 vfs_create_addrlist_af(int af, struct netexport *nep)
2092 {
2093 	struct radix_node_head *rnh = NULL;
2094 #if defined(INET) || defined(INET6)
2095 	struct radix_node_head *maskhead = nep->ne_maskhead;
2096 	int off;
2097 #endif
2098 
2099 	NE_ASSERT_LOCKED(nep);
2100 	KKASSERT(maskhead != NULL);
2101 	switch (af) {
2102 #ifdef INET
2103 	case AF_INET:
2104 		if ((rnh = nep->ne_inethead) == NULL) {
2105 			off = offsetof(struct sockaddr_in, sin_addr) << 3;
2106 			if (!rn_inithead((void **)&rnh, maskhead, off))
2107 				return (NULL);
2108 			nep->ne_inethead = rnh;
2109 		}
2110 		break;
2111 #endif
2112 #ifdef INET6
2113 	case AF_INET6:
2114 		if ((rnh = nep->ne_inet6head) == NULL) {
2115 			off = offsetof(struct sockaddr_in6, sin6_addr) << 3;
2116 			if (!rn_inithead((void **)&rnh, maskhead, off))
2117 				return (NULL);
2118 			nep->ne_inet6head = rnh;
2119 		}
2120 		break;
2121 #endif
2122 	}
2123 	return (rnh);
2124 }
2125 
2126 /*
2127  * helper function for freeing netcred elements
2128  */
2129 static void
2130 vfs_free_addrlist_af(struct radix_node_head **prnh)
2131 {
2132 	struct radix_node_head *rnh = *prnh;
2133 
2134 	(*rnh->rnh_walktree) (rnh, vfs_free_netcred, rnh);
2135 	kfree(rnh, M_RTABLE);
2136 	*prnh = NULL;
2137 }
2138 
2139 /*
2140  * helper function for freeing mask elements
2141  */
2142 static void
2143 vfs_free_addrlist_masks(struct radix_node_head **prnh)
2144 {
2145 	struct radix_node_head *rnh = *prnh;
2146 
2147 	(*rnh->rnh_walktree) (rnh, vfs_free_netcred_mask, rnh);
2148 	kfree(rnh, M_RTABLE);
2149 	*prnh = NULL;
2150 }
2151 
2152 /*
2153  * Free the net address hash lists that are hanging off the mount points.
2154  */
2155 static void
2156 vfs_free_addrlist(struct netexport *nep)
2157 {
2158 	NE_LOCK(nep);
2159 	if (nep->ne_inethead != NULL)
2160 		vfs_free_addrlist_af(&nep->ne_inethead);
2161 	if (nep->ne_inet6head != NULL)
2162 		vfs_free_addrlist_af(&nep->ne_inet6head);
2163 	if (nep->ne_maskhead)
2164 		vfs_free_addrlist_masks(&nep->ne_maskhead);
2165 	NE_UNLOCK(nep);
2166 }
2167 
2168 int
2169 vfs_export(struct mount *mp, struct netexport *nep,
2170 	   const struct export_args *argp)
2171 {
2172 	int error;
2173 
2174 	if (argp->ex_flags & MNT_DELEXPORT) {
2175 		if (mp->mnt_flag & MNT_EXPUBLIC) {
2176 			vfs_setpublicfs(NULL, NULL, NULL);
2177 			mp->mnt_flag &= ~MNT_EXPUBLIC;
2178 		}
2179 		vfs_free_addrlist(nep);
2180 		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
2181 	}
2182 	if (argp->ex_flags & MNT_EXPORTED) {
2183 		if (argp->ex_flags & MNT_EXPUBLIC) {
2184 			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
2185 				return (error);
2186 			mp->mnt_flag |= MNT_EXPUBLIC;
2187 		}
2188 		if ((error = vfs_hang_addrlist(mp, nep, argp)))
2189 			return (error);
2190 		mp->mnt_flag |= MNT_EXPORTED;
2191 	}
2192 	return (0);
2193 }
2194 
2195 
2196 /*
2197  * Set the publicly exported filesystem (WebNFS). Currently, only
2198  * one public filesystem is possible in the spec (RFC 2054 and 2055)
2199  */
2200 int
2201 vfs_setpublicfs(struct mount *mp, struct netexport *nep,
2202 		const struct export_args *argp)
2203 {
2204 	int error;
2205 	struct vnode *rvp;
2206 	char *cp;
2207 
2208 	/*
2209 	 * mp == NULL -> invalidate the current info, the FS is
2210 	 * no longer exported. May be called from either vfs_export
2211 	 * or unmount, so check if it hasn't already been done.
2212 	 */
2213 	if (mp == NULL) {
2214 		if (nfs_pub.np_valid) {
2215 			nfs_pub.np_valid = 0;
2216 			if (nfs_pub.np_index != NULL) {
2217 				kfree(nfs_pub.np_index, M_TEMP);
2218 				nfs_pub.np_index = NULL;
2219 			}
2220 		}
2221 		return (0);
2222 	}
2223 
2224 	/*
2225 	 * Only one allowed at a time.
2226 	 */
2227 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
2228 		return (EBUSY);
2229 
2230 	/*
2231 	 * Get real filehandle for root of exported FS.
2232 	 */
2233 	bzero((caddr_t)&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
2234 	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
2235 
2236 	if ((error = VFS_ROOT(mp, &rvp)))
2237 		return (error);
2238 
2239 	if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
2240 		return (error);
2241 
2242 	vput(rvp);
2243 
2244 	/*
2245 	 * If an indexfile was specified, pull it in.
2246 	 */
2247 	if (argp->ex_indexfile != NULL) {
2248 		int namelen;
2249 
2250 		error = vn_get_namelen(rvp, &namelen);
2251 		if (error)
2252 			return (error);
2253 		nfs_pub.np_index = kmalloc(namelen, M_TEMP, M_WAITOK);
2254 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
2255 		    namelen, NULL);
2256 		if (!error) {
2257 			/*
2258 			 * Check for illegal filenames.
2259 			 */
2260 			for (cp = nfs_pub.np_index; *cp; cp++) {
2261 				if (*cp == '/') {
2262 					error = EINVAL;
2263 					break;
2264 				}
2265 			}
2266 		}
2267 		if (error) {
2268 			kfree(nfs_pub.np_index, M_TEMP);
2269 			return (error);
2270 		}
2271 	}
2272 
2273 	nfs_pub.np_mount = mp;
2274 	nfs_pub.np_valid = 1;
2275 	return (0);
2276 }
2277 
2278 struct netcred *
2279 vfs_export_lookup(struct mount *mp, struct netexport *nep,
2280 		struct sockaddr *nam)
2281 {
2282 	struct netcred *np;
2283 	struct radix_node_head *rnh;
2284 	struct sockaddr *saddr;
2285 
2286 	np = NULL;
2287 	if (mp->mnt_flag & MNT_EXPORTED) {
2288 		/*
2289 		 * Lookup in the export list first.
2290 		 */
2291 		NE_LOCK(nep);
2292 		if (nam != NULL) {
2293 			saddr = nam;
2294 			switch (saddr->sa_family) {
2295 #ifdef INET
2296 			case AF_INET:
2297 				rnh = nep->ne_inethead;
2298 				break;
2299 #endif
2300 #ifdef INET6
2301 			case AF_INET6:
2302 				rnh = nep->ne_inet6head;
2303 				break;
2304 #endif
2305 			default:
2306 				rnh = NULL;
2307 			}
2308 			if (rnh != NULL) {
2309 				np = (struct netcred *)
2310 					(*rnh->rnh_matchaddr)((char *)saddr,
2311 							      rnh);
2312 				if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
2313 					np = NULL;
2314 			}
2315 		}
2316 		NE_UNLOCK(nep);
2317 		/*
2318 		 * If no address match, use the default if it exists.
2319 		 */
2320 		if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
2321 			np = &nep->ne_defexported;
2322 	}
2323 	return (np);
2324 }
2325 
2326 /*
2327  * perform msync on all vnodes under a mount point.  The mount point must
2328  * be locked.  This code is also responsible for lazy-freeing unreferenced
2329  * vnodes whos VM objects no longer contain pages.
2330  *
2331  * NOTE: MNT_WAIT still skips vnodes in the VXLOCK state.
2332  *
2333  * NOTE: XXX VOP_PUTPAGES and friends requires that the vnode be locked,
2334  * but vnode_pager_putpages() doesn't lock the vnode.  We have to do it
2335  * way up in this high level function.
2336  */
2337 static int vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data);
2338 static int vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data);
2339 
2340 void
2341 vfs_msync(struct mount *mp, int flags)
2342 {
2343 	int vmsc_flags;
2344 
2345 	/*
2346 	 * tmpfs sets this flag to prevent msync(), sync, and the
2347 	 * filesystem periodic syncer from trying to flush VM pages
2348 	 * to swap.  Only pure memory pressure flushes tmpfs VM pages
2349 	 * to swap.
2350 	 */
2351 	if (mp->mnt_kern_flag & MNTK_NOMSYNC)
2352 		return;
2353 
2354 	/*
2355 	 * Ok, scan the vnodes for work.  If the filesystem is using the
2356 	 * syncer thread feature we can use vsyncscan() instead of
2357 	 * vmntvnodescan(), which is much faster.
2358 	 */
2359 	vmsc_flags = VMSC_GETVP;
2360 	if (flags != MNT_WAIT)
2361 		vmsc_flags |= VMSC_NOWAIT;
2362 
2363 	if (mp->mnt_kern_flag & MNTK_THR_SYNC) {
2364 		vsyncscan(mp, vmsc_flags, vfs_msync_scan2,
2365 			  (void *)(intptr_t)flags);
2366 	} else {
2367 		vmntvnodescan(mp, vmsc_flags,
2368 			      vfs_msync_scan1, vfs_msync_scan2,
2369 			      (void *)(intptr_t)flags);
2370 	}
2371 }
2372 
2373 /*
2374  * scan1 is a fast pre-check.  There could be hundreds of thousands of
2375  * vnodes, we cannot afford to do anything heavy weight until we have a
2376  * fairly good indication that there is work to do.
2377  */
2378 static
2379 int
2380 vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data)
2381 {
2382 	int flags = (int)(intptr_t)data;
2383 
2384 	if ((vp->v_flag & VRECLAIMED) == 0) {
2385 		if (vp->v_auxrefs == 0 && VREFCNT(vp) <= 0 &&
2386 		    vp->v_object) {
2387 			return(0);	/* call scan2 */
2388 		}
2389 		if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
2390 		    (vp->v_flag & VOBJDIRTY) &&
2391 		    (flags == MNT_WAIT || vn_islocked(vp) == 0)) {
2392 			return(0);	/* call scan2 */
2393 		}
2394 	}
2395 
2396 	/*
2397 	 * do not call scan2, continue the loop
2398 	 */
2399 	return(-1);
2400 }
2401 
2402 /*
2403  * This callback is handed a locked vnode.
2404  */
2405 static
2406 int
2407 vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data)
2408 {
2409 	vm_object_t obj;
2410 	int flags = (int)(intptr_t)data;
2411 
2412 	if (vp->v_flag & VRECLAIMED)
2413 		return(0);
2414 
2415 	if ((mp->mnt_flag & MNT_RDONLY) == 0 && (vp->v_flag & VOBJDIRTY)) {
2416 		if ((obj = vp->v_object) != NULL) {
2417 			vm_object_page_clean(obj, 0, 0,
2418 			 flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
2419 		}
2420 	}
2421 	return(0);
2422 }
2423 
2424 /*
2425  * Wake up anyone interested in vp because it is being revoked.
2426  */
2427 void
2428 vn_gone(struct vnode *vp)
2429 {
2430 	lwkt_gettoken(&vp->v_token);
2431 	KNOTE(&vp->v_pollinfo.vpi_kqinfo.ki_note, NOTE_REVOKE);
2432 	lwkt_reltoken(&vp->v_token);
2433 }
2434 
2435 /*
2436  * extract the cdev_t from a VBLK or VCHR.  The vnode must have been opened
2437  * (or v_rdev might be NULL).
2438  */
2439 cdev_t
2440 vn_todev(struct vnode *vp)
2441 {
2442 	if (vp->v_type != VBLK && vp->v_type != VCHR)
2443 		return (NULL);
2444 	KKASSERT(vp->v_rdev != NULL);
2445 	return (vp->v_rdev);
2446 }
2447 
2448 /*
2449  * Check if vnode represents a disk device.  The vnode does not need to be
2450  * opened.
2451  *
2452  * MPALMOSTSAFE
2453  */
2454 int
2455 vn_isdisk(struct vnode *vp, int *errp)
2456 {
2457 	cdev_t dev;
2458 
2459 	if (vp->v_type != VCHR) {
2460 		if (errp != NULL)
2461 			*errp = ENOTBLK;
2462 		return (0);
2463 	}
2464 
2465 	dev = vp->v_rdev;
2466 
2467 	if (dev == NULL) {
2468 		if (errp != NULL)
2469 			*errp = ENXIO;
2470 		return (0);
2471 	}
2472 	if (dev_is_good(dev) == 0) {
2473 		if (errp != NULL)
2474 			*errp = ENXIO;
2475 		return (0);
2476 	}
2477 	if ((dev_dflags(dev) & D_DISK) == 0) {
2478 		if (errp != NULL)
2479 			*errp = ENOTBLK;
2480 		return (0);
2481 	}
2482 	if (errp != NULL)
2483 		*errp = 0;
2484 	return (1);
2485 }
2486 
2487 int
2488 vn_get_namelen(struct vnode *vp, int *namelen)
2489 {
2490 	int error;
2491 	register_t retval[2];
2492 
2493 	error = VOP_PATHCONF(vp, _PC_NAME_MAX, retval);
2494 	if (error)
2495 		return (error);
2496 	*namelen = (int)retval[0];
2497 	return (0);
2498 }
2499 
2500 int
2501 vop_write_dirent(int *error, struct uio *uio, ino_t d_ino, uint8_t d_type,
2502 		uint16_t d_namlen, const char *d_name)
2503 {
2504 	struct dirent *dp;
2505 	size_t len;
2506 
2507 	len = _DIRENT_RECLEN(d_namlen);
2508 	if (len > uio->uio_resid)
2509 		return(1);
2510 
2511 	dp = kmalloc(len, M_TEMP, M_WAITOK | M_ZERO);
2512 
2513 	dp->d_ino = d_ino;
2514 	dp->d_namlen = d_namlen;
2515 	dp->d_type = d_type;
2516 	bcopy(d_name, dp->d_name, d_namlen);
2517 
2518 	*error = uiomove((caddr_t)dp, len, uio);
2519 
2520 	kfree(dp, M_TEMP);
2521 
2522 	return(0);
2523 }
2524 
2525 void
2526 vn_mark_atime(struct vnode *vp, struct thread *td)
2527 {
2528 	struct proc *p = td->td_proc;
2529 	struct ucred *cred = p ? p->p_ucred : proc0.p_ucred;
2530 
2531 	if ((vp->v_mount->mnt_flag & (MNT_NOATIME | MNT_RDONLY)) == 0) {
2532 		VOP_MARKATIME(vp, cred);
2533 	}
2534 }
2535 
2536 /*
2537  * Calculate the number of entries in an inode-related chained hash table.
2538  * With today's memory sizes, maxvnodes can wind up being a very large
2539  * number.  There is no reason to waste memory, so tolerate some stacking.
2540  */
2541 int
2542 vfs_inodehashsize(void)
2543 {
2544 	int hsize;
2545 
2546 	hsize = 32;
2547 	while (hsize < maxvnodes)
2548 		hsize <<= 1;
2549 	while (hsize > maxvnodes * 2)
2550 		hsize >>= 1;		/* nominal 2x stacking */
2551 
2552 	if (maxvnodes > 1024 * 1024)
2553 		hsize >>= 1;		/* nominal 8x stacking */
2554 
2555 	if (maxvnodes > 128 * 1024)
2556 		hsize >>= 1;		/* nominal 4x stacking */
2557 
2558 	if (hsize < 16)
2559 		hsize = 16;
2560 
2561 	return hsize;
2562 }
2563