xref: /dragonfly/sys/kern/vfs_subr.c (revision 6877ea2d)
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/mplock2.h>
85 #include <vm/vm_page2.h>
86 
87 #include <netinet/in.h>
88 
89 static MALLOC_DEFINE(M_NETCRED, "Export Host", "Export host address structure");
90 
91 int numvnodes;
92 SYSCTL_INT(_debug, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0,
93     "Number of vnodes allocated");
94 int verbose_reclaims;
95 SYSCTL_INT(_debug, OID_AUTO, verbose_reclaims, CTLFLAG_RD, &verbose_reclaims, 0,
96     "Output filename of reclaimed vnode(s)");
97 
98 enum vtype iftovt_tab[16] = {
99 	VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
100 	VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
101 };
102 int vttoif_tab[9] = {
103 	0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
104 	S_IFSOCK, S_IFIFO, S_IFMT,
105 };
106 
107 static int reassignbufcalls;
108 SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW, &reassignbufcalls,
109     0, "Number of times buffers have been reassigned to the proper list");
110 
111 static int check_buf_overlap = 2;	/* invasive check */
112 SYSCTL_INT(_vfs, OID_AUTO, check_buf_overlap, CTLFLAG_RW, &check_buf_overlap,
113     0, "Enable overlapping buffer checks");
114 
115 int	nfs_mount_type = -1;
116 static struct lwkt_token spechash_token;
117 struct nfs_public nfs_pub;	/* publicly exported FS */
118 
119 int maxvnodes;
120 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
121 	   &maxvnodes, 0, "Maximum number of vnodes");
122 
123 static struct radix_node_head *vfs_create_addrlist_af(int af,
124 		    struct netexport *nep);
125 static void	vfs_free_addrlist (struct netexport *nep);
126 static int	vfs_free_netcred (struct radix_node *rn, void *w);
127 static void	vfs_free_addrlist_af (struct radix_node_head **prnh);
128 static int	vfs_hang_addrlist (struct mount *mp, struct netexport *nep,
129 	            const struct export_args *argp);
130 
131 int	prtactive = 0;		/* 1 => print out reclaim of active vnodes */
132 
133 /*
134  * Red black tree functions
135  */
136 static int rb_buf_compare(struct buf *b1, struct buf *b2);
137 RB_GENERATE2(buf_rb_tree, buf, b_rbnode, rb_buf_compare, off_t, b_loffset);
138 RB_GENERATE2(buf_rb_hash, buf, b_rbhash, rb_buf_compare, off_t, b_loffset);
139 
140 static int
141 rb_buf_compare(struct buf *b1, struct buf *b2)
142 {
143 	if (b1->b_loffset < b2->b_loffset)
144 		return(-1);
145 	if (b1->b_loffset > b2->b_loffset)
146 		return(1);
147 	return(0);
148 }
149 
150 /*
151  * Initialize the vnode management data structures.
152  *
153  * Called from vfsinit()
154  */
155 void
156 vfs_subr_init(void)
157 {
158 	int factor1;
159 	int factor2;
160 
161 	/*
162 	 * Desiredvnodes is kern.maxvnodes.  We want to scale it
163 	 * according to available system memory but we may also have
164 	 * to limit it based on available KVM.
165 	 *
166 	 * WARNING!  For machines with 64-256M of ram we have to be sure
167 	 *	     that the default limit scales down well due to HAMMER
168 	 *	     taking up significantly more memory per-vnode vs UFS.
169 	 *	     We want around ~5800 on a 128M machine.
170 	 *
171 	 * WARNING!  Now that KVM is substantially larger (e.g. 8TB+),
172 	 *	     also limit maxvnodes based on a 128GB metric.  This
173 	 *	     gives us something like ~3 millon vnodes.  sysctl
174 	 *	     can be used to increase it further if desired.
175 	 *
176 	 *	     For disk cachhing purposes, filesystems like HAMMER1
177 	 *	     and HAMMER2 will or can be told to cache file data
178 	 *	     via the block device instead of excessively in vnodes.
179 	 */
180 	factor1 = 25 * (sizeof(struct vm_object) + sizeof(struct vnode));
181 	factor2 = 30 * (sizeof(struct vm_object) + sizeof(struct vnode));
182 	maxvnodes = imin((int64_t)vmstats.v_page_count * PAGE_SIZE / factor1,
183 			 KvaSize / factor2);
184 	maxvnodes = imax(maxvnodes, maxproc * 8);
185 	maxvnodes = imin(maxvnodes, 64LL*1024*1024*1024 / factor2);
186 
187 	lwkt_token_init(&spechash_token, "spechash");
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, "Precision of file timestamps");
203 
204 /*
205  * Get a current timestamp.
206  *
207  * MPSAFE
208  */
209 void
210 vfs_timestamp(struct timespec *tsp)
211 {
212 	struct timeval tv;
213 
214 	switch (timestamp_precision) {
215 	case TSP_SEC:
216 		tsp->tv_sec = time_second;
217 		tsp->tv_nsec = 0;
218 		break;
219 	case TSP_HZ:
220 		getnanotime(tsp);
221 		break;
222 	case TSP_USEC:
223 		microtime(&tv);
224 		TIMEVAL_TO_TIMESPEC(&tv, tsp);
225 		break;
226 	case TSP_NSEC:
227 	default:
228 		nanotime(tsp);
229 		break;
230 	}
231 }
232 
233 /*
234  * Set vnode attributes to VNOVAL
235  */
236 void
237 vattr_null(struct vattr *vap)
238 {
239 	vap->va_type = VNON;
240 	vap->va_size = VNOVAL;
241 	vap->va_bytes = VNOVAL;
242 	vap->va_mode = VNOVAL;
243 	vap->va_nlink = VNOVAL;
244 	vap->va_uid = VNOVAL;
245 	vap->va_gid = VNOVAL;
246 	vap->va_fsid = VNOVAL;
247 	vap->va_fileid = VNOVAL;
248 	vap->va_blocksize = VNOVAL;
249 	vap->va_rmajor = VNOVAL;
250 	vap->va_rminor = VNOVAL;
251 	vap->va_atime.tv_sec = VNOVAL;
252 	vap->va_atime.tv_nsec = VNOVAL;
253 	vap->va_mtime.tv_sec = VNOVAL;
254 	vap->va_mtime.tv_nsec = VNOVAL;
255 	vap->va_ctime.tv_sec = VNOVAL;
256 	vap->va_ctime.tv_nsec = VNOVAL;
257 	vap->va_flags = VNOVAL;
258 	vap->va_gen = VNOVAL;
259 	vap->va_vaflags = 0;
260 	/* va_*_uuid fields are only valid if related flags are set */
261 }
262 
263 /*
264  * Flush out and invalidate all buffers associated with a vnode.
265  *
266  * vp must be locked.
267  */
268 static int vinvalbuf_bp(struct buf *bp, void *data);
269 
270 struct vinvalbuf_bp_info {
271 	struct vnode *vp;
272 	int slptimeo;
273 	int lkflags;
274 	int flags;
275 	int clean;
276 };
277 
278 int
279 vinvalbuf(struct vnode *vp, int flags, int slpflag, int slptimeo)
280 {
281 	struct vinvalbuf_bp_info info;
282 	vm_object_t object;
283 	int error;
284 
285 	lwkt_gettoken(&vp->v_token);
286 
287 	/*
288 	 * If we are being asked to save, call fsync to ensure that the inode
289 	 * is updated.
290 	 */
291 	if (flags & V_SAVE) {
292 		error = bio_track_wait(&vp->v_track_write, slpflag, slptimeo);
293 		if (error)
294 			goto done;
295 		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
296 			if ((error = VOP_FSYNC(vp, MNT_WAIT, 0)) != 0)
297 				goto done;
298 #if 0
299 			/*
300 			 * Dirty bufs may be left or generated via races
301 			 * in circumstances where vinvalbuf() is called on
302 			 * a vnode not undergoing reclamation.   Only
303 			 * panic if we are trying to reclaim the vnode.
304 			 */
305 			if ((vp->v_flag & VRECLAIMED) &&
306 			    (bio_track_active(&vp->v_track_write) ||
307 			    !RB_EMPTY(&vp->v_rbdirty_tree))) {
308 				panic("vinvalbuf: dirty bufs");
309 			}
310 #endif
311 		}
312   	}
313 	info.slptimeo = slptimeo;
314 	info.lkflags = LK_EXCLUSIVE | LK_SLEEPFAIL;
315 	if (slpflag & PCATCH)
316 		info.lkflags |= LK_PCATCH;
317 	info.flags = flags;
318 	info.vp = vp;
319 
320 	/*
321 	 * Flush the buffer cache until nothing is left, wait for all I/O
322 	 * to complete.  At least one pass is required.  We might block
323 	 * in the pip code so we have to re-check.  Order is important.
324 	 */
325 	do {
326 		/*
327 		 * Flush buffer cache
328 		 */
329 		if (!RB_EMPTY(&vp->v_rbclean_tree)) {
330 			info.clean = 1;
331 			error = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
332 					NULL, vinvalbuf_bp, &info);
333 		}
334 		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
335 			info.clean = 0;
336 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
337 					NULL, vinvalbuf_bp, &info);
338 		}
339 
340 		/*
341 		 * Wait for I/O completion.
342 		 */
343 		bio_track_wait(&vp->v_track_write, 0, 0);
344 		if ((object = vp->v_object) != NULL)
345 			refcount_wait(&object->paging_in_progress, "vnvlbx");
346 	} while (bio_track_active(&vp->v_track_write) ||
347 		 !RB_EMPTY(&vp->v_rbclean_tree) ||
348 		 !RB_EMPTY(&vp->v_rbdirty_tree));
349 
350 	/*
351 	 * Destroy the copy in the VM cache, too.
352 	 */
353 	if ((object = vp->v_object) != NULL) {
354 		vm_object_page_remove(object, 0, 0,
355 			(flags & V_SAVE) ? TRUE : FALSE);
356 	}
357 
358 	if (!RB_EMPTY(&vp->v_rbdirty_tree) || !RB_EMPTY(&vp->v_rbclean_tree))
359 		panic("vinvalbuf: flush failed");
360 	if (!RB_EMPTY(&vp->v_rbhash_tree))
361 		panic("vinvalbuf: flush failed, buffers still present");
362 	error = 0;
363 done:
364 	lwkt_reltoken(&vp->v_token);
365 	return (error);
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 		atomic_add_int(&bp->b_refs, 1);
376 		error = BUF_TIMELOCK(bp, info->lkflags,
377 				     "vinvalbuf", info->slptimeo);
378 		atomic_subtract_int(&bp->b_refs, 1);
379 		if (error == 0) {
380 			BUF_UNLOCK(bp);
381 			error = ENOLCK;
382 		}
383 		if (error == ENOLCK)
384 			return(0);
385 		return (-error);
386 	}
387 	KKASSERT(bp->b_vp == info->vp);
388 
389 	/*
390 	 * Must check clean/dirty status after successfully locking as
391 	 * it may race.
392 	 */
393 	if ((info->clean && (bp->b_flags & B_DELWRI)) ||
394 	    (info->clean == 0 && (bp->b_flags & B_DELWRI) == 0)) {
395 		BUF_UNLOCK(bp);
396 		return(0);
397 	}
398 
399 	/*
400 	 * NOTE:  NO B_LOCKED CHECK.  Also no buf_checkwrite()
401 	 * check.  This code will write out the buffer, period.
402 	 */
403 	bremfree(bp);
404 	if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
405 	    (info->flags & V_SAVE)) {
406 		cluster_awrite(bp);
407 	} else if (info->flags & V_SAVE) {
408 		/*
409 		 * Cannot set B_NOCACHE on a clean buffer as this will
410 		 * destroy the VM backing store which might actually
411 		 * be dirty (and unsynchronized).
412 		 */
413 		bp->b_flags |= (B_INVAL | B_RELBUF);
414 		brelse(bp);
415 	} else {
416 		bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
417 		brelse(bp);
418 	}
419 	return(0);
420 }
421 
422 /*
423  * Truncate a file's buffer and pages to a specified length.  This
424  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
425  * sync activity.
426  *
427  * The vnode must be locked.
428  */
429 static int vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data);
430 static int vtruncbuf_bp_trunc(struct buf *bp, void *data);
431 static int vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data);
432 static int vtruncbuf_bp_metasync(struct buf *bp, void *data);
433 
434 struct vtruncbuf_info {
435 	struct vnode *vp;
436 	off_t	truncloffset;
437 	int	clean;
438 };
439 
440 int
441 vtruncbuf(struct vnode *vp, off_t length, int blksize)
442 {
443 	struct vtruncbuf_info info;
444 	const char *filename;
445 	int count;
446 
447 	/*
448 	 * Round up to the *next* block, then destroy the buffers in question.
449 	 * Since we are only removing some of the buffers we must rely on the
450 	 * scan count to determine whether a loop is necessary.
451 	 */
452 	if ((count = (int)(length % blksize)) != 0)
453 		info.truncloffset = length + (blksize - count);
454 	else
455 		info.truncloffset = length;
456 	info.vp = vp;
457 
458 	lwkt_gettoken(&vp->v_token);
459 	do {
460 		info.clean = 1;
461 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
462 				vtruncbuf_bp_trunc_cmp,
463 				vtruncbuf_bp_trunc, &info);
464 		info.clean = 0;
465 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
466 				vtruncbuf_bp_trunc_cmp,
467 				vtruncbuf_bp_trunc, &info);
468 	} while(count);
469 
470 	/*
471 	 * For safety, fsync any remaining metadata if the file is not being
472 	 * truncated to 0.  Since the metadata does not represent the entire
473 	 * dirty list we have to rely on the hit count to ensure that we get
474 	 * all of it.
475 	 */
476 	if (length > 0) {
477 		do {
478 			count = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
479 					vtruncbuf_bp_metasync_cmp,
480 					vtruncbuf_bp_metasync, &info);
481 		} while (count);
482 	}
483 
484 	/*
485 	 * Clean out any left over VM backing store.
486 	 *
487 	 * It is possible to have in-progress I/O from buffers that were
488 	 * not part of the truncation.  This should not happen if we
489 	 * are truncating to 0-length.
490 	 */
491 	vnode_pager_setsize(vp, length);
492 	bio_track_wait(&vp->v_track_write, 0, 0);
493 
494 	/*
495 	 * Debugging only
496 	 */
497 	spin_lock(&vp->v_spin);
498 	filename = TAILQ_FIRST(&vp->v_namecache) ?
499 		   TAILQ_FIRST(&vp->v_namecache)->nc_name : "?";
500 	spin_unlock(&vp->v_spin);
501 
502 	/*
503 	 * Make sure no buffers were instantiated while we were trying
504 	 * to clean out the remaining VM pages.  This could occur due
505 	 * to busy dirty VM pages being flushed out to disk.
506 	 */
507 	do {
508 		info.clean = 1;
509 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
510 				vtruncbuf_bp_trunc_cmp,
511 				vtruncbuf_bp_trunc, &info);
512 		info.clean = 0;
513 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
514 				vtruncbuf_bp_trunc_cmp,
515 				vtruncbuf_bp_trunc, &info);
516 		if (count) {
517 			kprintf("Warning: vtruncbuf():  Had to re-clean %d "
518 			       "left over buffers in %s\n", count, filename);
519 		}
520 	} while(count);
521 
522 	lwkt_reltoken(&vp->v_token);
523 
524 	return (0);
525 }
526 
527 /*
528  * The callback buffer is beyond the new file EOF and must be destroyed.
529  * Note that the compare function must conform to the RB_SCAN's requirements.
530  */
531 static
532 int
533 vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data)
534 {
535 	struct vtruncbuf_info *info = data;
536 
537 	if (bp->b_loffset >= info->truncloffset)
538 		return(0);
539 	return(-1);
540 }
541 
542 static
543 int
544 vtruncbuf_bp_trunc(struct buf *bp, void *data)
545 {
546 	struct vtruncbuf_info *info = data;
547 
548 	/*
549 	 * Do not try to use a buffer we cannot immediately lock, but sleep
550 	 * anyway to prevent a livelock.  The code will loop until all buffers
551 	 * can be acted upon.
552 	 *
553 	 * We must always revalidate the buffer after locking it to deal
554 	 * with MP races.
555 	 */
556 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
557 		atomic_add_int(&bp->b_refs, 1);
558 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
559 			BUF_UNLOCK(bp);
560 		atomic_subtract_int(&bp->b_refs, 1);
561 	} else if ((info->clean && (bp->b_flags & B_DELWRI)) ||
562 		   (info->clean == 0 && (bp->b_flags & B_DELWRI) == 0) ||
563 		   bp->b_vp != info->vp ||
564 		   vtruncbuf_bp_trunc_cmp(bp, data)) {
565 		BUF_UNLOCK(bp);
566 	} else {
567 		bremfree(bp);
568 		bp->b_flags |= (B_INVAL | B_RELBUF | B_NOCACHE);
569 		brelse(bp);
570 	}
571 	return(1);
572 }
573 
574 /*
575  * Fsync all meta-data after truncating a file to be non-zero.  Only metadata
576  * blocks (with a negative loffset) are scanned.
577  * Note that the compare function must conform to the RB_SCAN's requirements.
578  */
579 static int
580 vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data __unused)
581 {
582 	if (bp->b_loffset < 0)
583 		return(0);
584 	return(1);
585 }
586 
587 static int
588 vtruncbuf_bp_metasync(struct buf *bp, void *data)
589 {
590 	struct vtruncbuf_info *info = data;
591 
592 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
593 		atomic_add_int(&bp->b_refs, 1);
594 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
595 			BUF_UNLOCK(bp);
596 		atomic_subtract_int(&bp->b_refs, 1);
597 	} else if ((bp->b_flags & B_DELWRI) == 0 ||
598 		   bp->b_vp != info->vp ||
599 		   vtruncbuf_bp_metasync_cmp(bp, data)) {
600 		BUF_UNLOCK(bp);
601 	} else {
602 		bremfree(bp);
603 		if (bp->b_vp == info->vp)
604 			bawrite(bp);
605 		else
606 			bwrite(bp);
607 	}
608 	return(1);
609 }
610 
611 /*
612  * vfsync - implements a multipass fsync on a file which understands
613  * dependancies and meta-data.  The passed vnode must be locked.  The
614  * waitfor argument may be MNT_WAIT or MNT_NOWAIT, or MNT_LAZY.
615  *
616  * When fsyncing data asynchronously just do one consolidated pass starting
617  * with the most negative block number.  This may not get all the data due
618  * to dependancies.
619  *
620  * When fsyncing data synchronously do a data pass, then a metadata pass,
621  * then do additional data+metadata passes to try to get all the data out.
622  *
623  * Caller must ref the vnode but does not have to lock it.
624  */
625 static int vfsync_wait_output(struct vnode *vp,
626 			    int (*waitoutput)(struct vnode *, struct thread *));
627 static int vfsync_dummy_cmp(struct buf *bp __unused, void *data __unused);
628 static int vfsync_data_only_cmp(struct buf *bp, void *data);
629 static int vfsync_meta_only_cmp(struct buf *bp, void *data);
630 static int vfsync_lazy_range_cmp(struct buf *bp, void *data);
631 static int vfsync_bp(struct buf *bp, void *data);
632 
633 struct vfsync_info {
634 	struct vnode *vp;
635 	int fastpass;
636 	int synchronous;
637 	int syncdeps;
638 	int lazycount;
639 	int lazylimit;
640 	int skippedbufs;
641 	int (*checkdef)(struct buf *);
642 	int (*cmpfunc)(struct buf *, void *);
643 };
644 
645 int
646 vfsync(struct vnode *vp, int waitfor, int passes,
647 	int (*checkdef)(struct buf *),
648 	int (*waitoutput)(struct vnode *, struct thread *))
649 {
650 	struct vfsync_info info;
651 	int error;
652 
653 	bzero(&info, sizeof(info));
654 	info.vp = vp;
655 	if ((info.checkdef = checkdef) == NULL)
656 		info.syncdeps = 1;
657 
658 	lwkt_gettoken(&vp->v_token);
659 
660 	switch(waitfor) {
661 	case MNT_LAZY | MNT_NOWAIT:
662 	case MNT_LAZY:
663 		/*
664 		 * Lazy (filesystem syncer typ) Asynchronous plus limit the
665 		 * number of data (not meta) pages we try to flush to 1MB.
666 		 * A non-zero return means that lazy limit was reached.
667 		 */
668 		info.lazylimit = 1024 * 1024;
669 		info.syncdeps = 1;
670 		info.cmpfunc = vfsync_lazy_range_cmp;
671 		error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
672 				vfsync_lazy_range_cmp, vfsync_bp, &info);
673 		info.cmpfunc = vfsync_meta_only_cmp;
674 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
675 			vfsync_meta_only_cmp, vfsync_bp, &info);
676 		if (error == 0)
677 			vp->v_lazyw = 0;
678 		else if (!RB_EMPTY(&vp->v_rbdirty_tree))
679 			vn_syncer_add(vp, 1);
680 		error = 0;
681 		break;
682 	case MNT_NOWAIT:
683 		/*
684 		 * Asynchronous.  Do a data-only pass and a meta-only pass.
685 		 */
686 		info.syncdeps = 1;
687 		info.cmpfunc = vfsync_data_only_cmp;
688 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
689 			vfsync_bp, &info);
690 		info.cmpfunc = vfsync_meta_only_cmp;
691 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_meta_only_cmp,
692 			vfsync_bp, &info);
693 		error = 0;
694 		break;
695 	default:
696 		/*
697 		 * Synchronous.  Do a data-only pass, then a meta-data+data
698 		 * pass, then additional integrated passes to try to get
699 		 * all the dependancies flushed.
700 		 */
701 		info.cmpfunc = vfsync_data_only_cmp;
702 		info.fastpass = 1;
703 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
704 			vfsync_bp, &info);
705 		info.fastpass = 0;
706 		error = vfsync_wait_output(vp, waitoutput);
707 		if (error == 0) {
708 			info.skippedbufs = 0;
709 			info.cmpfunc = vfsync_dummy_cmp;
710 			RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
711 				vfsync_bp, &info);
712 			error = vfsync_wait_output(vp, waitoutput);
713 			if (info.skippedbufs) {
714 				kprintf("Warning: vfsync skipped %d dirty "
715 					"buf%s in pass2!\n",
716 					info.skippedbufs,
717 					((info.skippedbufs > 1) ? "s" : ""));
718 			}
719 		}
720 		while (error == 0 && passes > 0 &&
721 		       !RB_EMPTY(&vp->v_rbdirty_tree)
722 		) {
723 			info.skippedbufs = 0;
724 			if (--passes == 0) {
725 				info.synchronous = 1;
726 				info.syncdeps = 1;
727 			}
728 			info.cmpfunc = vfsync_dummy_cmp;
729 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
730 					vfsync_bp, &info);
731 			if (error < 0)
732 				error = -error;
733 			info.syncdeps = 1;
734 			if (error == 0)
735 				error = vfsync_wait_output(vp, waitoutput);
736 			if (info.skippedbufs && passes == 0) {
737 				kprintf("Warning: vfsync skipped %d dirty "
738 					"buf%s in final pass!\n",
739 					info.skippedbufs,
740 					((info.skippedbufs > 1) ? "s" : ""));
741 			}
742 		}
743 #if 0
744 		/*
745 		 * This case can occur normally because vnode lock might
746 		 * not be held.
747 		 */
748 		if (!RB_EMPTY(&vp->v_rbdirty_tree))
749 			kprintf("dirty bufs left after final pass\n");
750 #endif
751 		break;
752 	}
753 	lwkt_reltoken(&vp->v_token);
754 
755 	return(error);
756 }
757 
758 static int
759 vfsync_wait_output(struct vnode *vp,
760 		   int (*waitoutput)(struct vnode *, struct thread *))
761 {
762 	int error;
763 
764 	error = bio_track_wait(&vp->v_track_write, 0, 0);
765 	if (waitoutput)
766 		error = waitoutput(vp, curthread);
767 	return(error);
768 }
769 
770 static int
771 vfsync_dummy_cmp(struct buf *bp __unused, void *data __unused)
772 {
773 	return(0);
774 }
775 
776 static int
777 vfsync_data_only_cmp(struct buf *bp, void *data)
778 {
779 	if (bp->b_loffset < 0)
780 		return(-1);
781 	return(0);
782 }
783 
784 static int
785 vfsync_meta_only_cmp(struct buf *bp, void *data)
786 {
787 	if (bp->b_loffset < 0)
788 		return(0);
789 	return(1);
790 }
791 
792 static int
793 vfsync_lazy_range_cmp(struct buf *bp, void *data)
794 {
795 	struct vfsync_info *info = data;
796 
797 	if (bp->b_loffset < info->vp->v_lazyw)
798 		return(-1);
799 	return(0);
800 }
801 
802 static int
803 vfsync_bp(struct buf *bp, void *data)
804 {
805 	struct vfsync_info *info = data;
806 	struct vnode *vp = info->vp;
807 	int error;
808 
809 	if (info->fastpass) {
810 		/*
811 		 * Ignore buffers that we cannot immediately lock.
812 		 */
813 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
814 			if (BUF_TIMELOCK(bp, LK_EXCLUSIVE, "bflst1", 1)) {
815 				++info->skippedbufs;
816 				return(0);
817 			}
818 		}
819 	} else if (info->synchronous == 0) {
820 		/*
821 		 * Normal pass, give the buffer a little time to become
822 		 * available to us.
823 		 */
824 		if (BUF_TIMELOCK(bp, LK_EXCLUSIVE, "bflst2", hz / 10)) {
825 			++info->skippedbufs;
826 			return(0);
827 		}
828 	} else {
829 		/*
830 		 * Synchronous pass, give the buffer a lot of time before
831 		 * giving up.
832 		 */
833 		if (BUF_TIMELOCK(bp, LK_EXCLUSIVE, "bflst3", hz * 10)) {
834 			++info->skippedbufs;
835 			return(0);
836 		}
837 	}
838 
839 	/*
840 	 * We must revalidate the buffer after locking.
841 	 */
842 	if ((bp->b_flags & B_DELWRI) == 0 ||
843 	    bp->b_vp != info->vp ||
844 	    info->cmpfunc(bp, data)) {
845 		BUF_UNLOCK(bp);
846 		return(0);
847 	}
848 
849 	/*
850 	 * If syncdeps is not set we do not try to write buffers which have
851 	 * dependancies.
852 	 */
853 	if (!info->synchronous && info->syncdeps == 0 && info->checkdef(bp)) {
854 		BUF_UNLOCK(bp);
855 		return(0);
856 	}
857 
858 	/*
859 	 * B_NEEDCOMMIT (primarily used by NFS) is a state where the buffer
860 	 * has been written but an additional handshake with the device
861 	 * is required before we can dispose of the buffer.  We have no idea
862 	 * how to do this so we have to skip these buffers.
863 	 */
864 	if (bp->b_flags & B_NEEDCOMMIT) {
865 		BUF_UNLOCK(bp);
866 		return(0);
867 	}
868 
869 	/*
870 	 * Ask bioops if it is ok to sync.  If not the VFS may have
871 	 * set B_LOCKED so we have to cycle the buffer.
872 	 */
873 	if (LIST_FIRST(&bp->b_dep) != NULL && buf_checkwrite(bp)) {
874 		bremfree(bp);
875 		brelse(bp);
876 		return(0);
877 	}
878 
879 	if (info->synchronous) {
880 		/*
881 		 * Synchronous flush.  An error may be returned and will
882 		 * stop the scan.
883 		 */
884 		bremfree(bp);
885 		error = bwrite(bp);
886 	} else {
887 		/*
888 		 * Asynchronous flush.  We use the error return to support
889 		 * MNT_LAZY flushes.
890 		 *
891 		 * In low-memory situations we revert to synchronous
892 		 * operation.  This should theoretically prevent the I/O
893 		 * path from exhausting memory in a non-recoverable way.
894 		 */
895 		vp->v_lazyw = bp->b_loffset;
896 		bremfree(bp);
897 		if (vm_page_count_min(0)) {
898 			/* low memory */
899 			info->lazycount += bp->b_bufsize;
900 			bwrite(bp);
901 		} else {
902 			/* normal */
903 			info->lazycount += cluster_awrite(bp);
904 			waitrunningbufspace();
905 			/*vm_wait_nominal();*/
906 		}
907 		if (info->lazylimit && info->lazycount >= info->lazylimit)
908 			error = 1;
909 		else
910 			error = 0;
911 	}
912 	return(-error);
913 }
914 
915 /*
916  * Associate a buffer with a vnode.
917  *
918  * MPSAFE
919  */
920 int
921 bgetvp(struct vnode *vp, struct buf *bp, int testsize)
922 {
923 	KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));
924 	KKASSERT((bp->b_flags & (B_HASHED|B_DELWRI|B_VNCLEAN|B_VNDIRTY)) == 0);
925 
926 	/*
927 	 * Insert onto list for new vnode.
928 	 */
929 	lwkt_gettoken(&vp->v_token);
930 
931 	if (buf_rb_hash_RB_INSERT(&vp->v_rbhash_tree, bp)) {
932 		lwkt_reltoken(&vp->v_token);
933 		return (EEXIST);
934 	}
935 
936 	/*
937 	 * Diagnostics (mainly for HAMMER debugging).  Check for
938 	 * overlapping buffers.
939 	 */
940 	if (check_buf_overlap) {
941 		struct buf *bx;
942 		bx = buf_rb_hash_RB_PREV(bp);
943 		if (bx) {
944 			if (bx->b_loffset + bx->b_bufsize > bp->b_loffset) {
945 				kprintf("bgetvp: overlapl %016jx/%d %016jx "
946 					"bx %p bp %p\n",
947 					(intmax_t)bx->b_loffset,
948 					bx->b_bufsize,
949 					(intmax_t)bp->b_loffset,
950 					bx, bp);
951 				if (check_buf_overlap > 1)
952 					panic("bgetvp - overlapping buffer");
953 			}
954 		}
955 		bx = buf_rb_hash_RB_NEXT(bp);
956 		if (bx) {
957 			if (bp->b_loffset + testsize > bx->b_loffset) {
958 				kprintf("bgetvp: overlapr %016jx/%d %016jx "
959 					"bp %p bx %p\n",
960 					(intmax_t)bp->b_loffset,
961 					testsize,
962 					(intmax_t)bx->b_loffset,
963 					bp, bx);
964 				if (check_buf_overlap > 1)
965 					panic("bgetvp - overlapping buffer");
966 			}
967 		}
968 	}
969 	bp->b_vp = vp;
970 	bp->b_flags |= B_HASHED;
971 	bp->b_flags |= B_VNCLEAN;
972 	if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp))
973 		panic("reassignbuf: dup lblk/clean vp %p bp %p", vp, bp);
974 	/*vhold(vp);*/
975 	lwkt_reltoken(&vp->v_token);
976 	return(0);
977 }
978 
979 /*
980  * Disassociate a buffer from a vnode.
981  *
982  * MPSAFE
983  */
984 void
985 brelvp(struct buf *bp)
986 {
987 	struct vnode *vp;
988 
989 	KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
990 
991 	/*
992 	 * Delete from old vnode list, if on one.
993 	 */
994 	vp = bp->b_vp;
995 	lwkt_gettoken(&vp->v_token);
996 	if (bp->b_flags & (B_VNDIRTY | B_VNCLEAN)) {
997 		if (bp->b_flags & B_VNDIRTY)
998 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
999 		else
1000 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
1001 		bp->b_flags &= ~(B_VNDIRTY | B_VNCLEAN);
1002 	}
1003 	if (bp->b_flags & B_HASHED) {
1004 		buf_rb_hash_RB_REMOVE(&vp->v_rbhash_tree, bp);
1005 		bp->b_flags &= ~B_HASHED;
1006 	}
1007 
1008 	/*
1009 	 * Only remove from synclist when no dirty buffers are left AND
1010 	 * the VFS has not flagged the vnode's inode as being dirty.
1011 	 */
1012 	if ((vp->v_flag & (VONWORKLST | VISDIRTY | VOBJDIRTY)) == VONWORKLST &&
1013 	    RB_EMPTY(&vp->v_rbdirty_tree)) {
1014 		vn_syncer_remove(vp, 0);
1015 	}
1016 	bp->b_vp = NULL;
1017 
1018 	lwkt_reltoken(&vp->v_token);
1019 
1020 	/*vdrop(vp);*/
1021 }
1022 
1023 /*
1024  * Reassign the buffer to the proper clean/dirty list based on B_DELWRI.
1025  * This routine is called when the state of the B_DELWRI bit is changed.
1026  *
1027  * Must be called with vp->v_token held.
1028  * MPSAFE
1029  */
1030 void
1031 reassignbuf(struct buf *bp)
1032 {
1033 	struct vnode *vp = bp->b_vp;
1034 	int delay;
1035 
1036 	ASSERT_LWKT_TOKEN_HELD(&vp->v_token);
1037 	++reassignbufcalls;
1038 
1039 	/*
1040 	 * B_PAGING flagged buffers cannot be reassigned because their vp
1041 	 * is not fully linked in.
1042 	 */
1043 	if (bp->b_flags & B_PAGING)
1044 		panic("cannot reassign paging buffer");
1045 
1046 	if (bp->b_flags & B_DELWRI) {
1047 		/*
1048 		 * Move to the dirty list, add the vnode to the worklist
1049 		 */
1050 		if (bp->b_flags & B_VNCLEAN) {
1051 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
1052 			bp->b_flags &= ~B_VNCLEAN;
1053 		}
1054 		if ((bp->b_flags & B_VNDIRTY) == 0) {
1055 			if (buf_rb_tree_RB_INSERT(&vp->v_rbdirty_tree, bp)) {
1056 				panic("reassignbuf: dup lblk vp %p bp %p",
1057 				      vp, bp);
1058 			}
1059 			bp->b_flags |= B_VNDIRTY;
1060 		}
1061 		if ((vp->v_flag & VONWORKLST) == 0) {
1062 			switch (vp->v_type) {
1063 			case VDIR:
1064 				delay = dirdelay;
1065 				break;
1066 			case VCHR:
1067 			case VBLK:
1068 				if (vp->v_rdev &&
1069 				    vp->v_rdev->si_mountpoint != NULL) {
1070 					delay = metadelay;
1071 					break;
1072 				}
1073 				/* fall through */
1074 			default:
1075 				delay = filedelay;
1076 			}
1077 			vn_syncer_add(vp, delay);
1078 		}
1079 	} else {
1080 		/*
1081 		 * Move to the clean list, remove the vnode from the worklist
1082 		 * if no dirty blocks remain.
1083 		 */
1084 		if (bp->b_flags & B_VNDIRTY) {
1085 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
1086 			bp->b_flags &= ~B_VNDIRTY;
1087 		}
1088 		if ((bp->b_flags & B_VNCLEAN) == 0) {
1089 			if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp)) {
1090 				panic("reassignbuf: dup lblk vp %p bp %p",
1091 				      vp, bp);
1092 			}
1093 			bp->b_flags |= B_VNCLEAN;
1094 		}
1095 
1096 		/*
1097 		 * Only remove from synclist when no dirty buffers are left
1098 		 * AND the VFS has not flagged the vnode's inode as being
1099 		 * dirty.
1100 		 */
1101 		if ((vp->v_flag & (VONWORKLST | VISDIRTY | VOBJDIRTY)) ==
1102 		     VONWORKLST &&
1103 		    RB_EMPTY(&vp->v_rbdirty_tree)) {
1104 			vn_syncer_remove(vp, 0);
1105 		}
1106 	}
1107 }
1108 
1109 /*
1110  * Create a vnode for a block device.  Used for mounting the root file
1111  * system.
1112  *
1113  * A vref()'d vnode is returned.
1114  */
1115 extern struct vop_ops *devfs_vnode_dev_vops_p;
1116 int
1117 bdevvp(cdev_t dev, struct vnode **vpp)
1118 {
1119 	struct vnode *vp;
1120 	struct vnode *nvp;
1121 	int error;
1122 
1123 	if (dev == NULL) {
1124 		*vpp = NULLVP;
1125 		return (ENXIO);
1126 	}
1127 	error = getspecialvnode(VT_NON, NULL, &devfs_vnode_dev_vops_p,
1128 				&nvp, 0, 0);
1129 	if (error) {
1130 		*vpp = NULLVP;
1131 		return (error);
1132 	}
1133 	vp = nvp;
1134 	vp->v_type = VCHR;
1135 #if 0
1136 	vp->v_rdev = dev;
1137 #endif
1138 	v_associate_rdev(vp, dev);
1139 	vp->v_umajor = dev->si_umajor;
1140 	vp->v_uminor = dev->si_uminor;
1141 	vx_unlock(vp);
1142 	*vpp = vp;
1143 	return (0);
1144 }
1145 
1146 int
1147 v_associate_rdev(struct vnode *vp, cdev_t dev)
1148 {
1149 	if (dev == NULL)
1150 		return(ENXIO);
1151 	if (dev_is_good(dev) == 0)
1152 		return(ENXIO);
1153 	KKASSERT(vp->v_rdev == NULL);
1154 	vp->v_rdev = reference_dev(dev);
1155 	lwkt_gettoken(&spechash_token);
1156 	SLIST_INSERT_HEAD(&dev->si_hlist, vp, v_cdevnext);
1157 	lwkt_reltoken(&spechash_token);
1158 	return(0);
1159 }
1160 
1161 void
1162 v_release_rdev(struct vnode *vp)
1163 {
1164 	cdev_t dev;
1165 
1166 	if ((dev = vp->v_rdev) != NULL) {
1167 		lwkt_gettoken(&spechash_token);
1168 		SLIST_REMOVE(&dev->si_hlist, vp, vnode, v_cdevnext);
1169 		vp->v_rdev = NULL;
1170 		release_dev(dev);
1171 		lwkt_reltoken(&spechash_token);
1172 	}
1173 }
1174 
1175 /*
1176  * Add a vnode to the alias list hung off the cdev_t.  We only associate
1177  * the device number with the vnode.  The actual device is not associated
1178  * until the vnode is opened (usually in spec_open()), and will be
1179  * disassociated on last close.
1180  */
1181 void
1182 addaliasu(struct vnode *nvp, int x, int y)
1183 {
1184 	if (nvp->v_type != VBLK && nvp->v_type != VCHR)
1185 		panic("addaliasu on non-special vnode");
1186 	nvp->v_umajor = x;
1187 	nvp->v_uminor = y;
1188 }
1189 
1190 /*
1191  * Simple call that a filesystem can make to try to get rid of a
1192  * vnode.  It will fail if anyone is referencing the vnode (including
1193  * the caller).
1194  *
1195  * The filesystem can check whether its in-memory inode structure still
1196  * references the vp on return.
1197  *
1198  * May only be called if the vnode is in a known state (i.e. being prevented
1199  * from being deallocated by some other condition such as a vfs inode hold).
1200  */
1201 void
1202 vclean_unlocked(struct vnode *vp)
1203 {
1204 	vx_get(vp);
1205 	if (VREFCNT(vp) <= 1)
1206 		vgone_vxlocked(vp);
1207 	vx_put(vp);
1208 }
1209 
1210 /*
1211  * Disassociate a vnode from its underlying filesystem.
1212  *
1213  * The vnode must be VX locked and referenced.  In all normal situations
1214  * there are no active references.  If vclean_vxlocked() is called while
1215  * there are active references, the vnode is being ripped out and we have
1216  * to call VOP_CLOSE() as appropriate before we can reclaim it.
1217  */
1218 void
1219 vclean_vxlocked(struct vnode *vp, int flags)
1220 {
1221 	int active;
1222 	int n;
1223 	vm_object_t object;
1224 	struct namecache *ncp;
1225 
1226 	/*
1227 	 * If the vnode has already been reclaimed we have nothing to do.
1228 	 */
1229 	if (vp->v_flag & VRECLAIMED)
1230 		return;
1231 
1232 	/*
1233 	 * Set flag to interlock operation, flag finalization to ensure
1234 	 * that the vnode winds up on the inactive list, and set v_act to 0.
1235 	 */
1236 	vsetflags(vp, VRECLAIMED);
1237 	atomic_set_int(&vp->v_refcnt, VREF_FINALIZE);
1238 	vp->v_act = 0;
1239 
1240 	if (verbose_reclaims) {
1241 		if ((ncp = TAILQ_FIRST(&vp->v_namecache)) != NULL)
1242 			kprintf("Debug: reclaim %p %s\n", vp, ncp->nc_name);
1243 	}
1244 
1245 	/*
1246 	 * Scrap the vfs cache
1247 	 */
1248 	while (cache_inval_vp(vp, 0) != 0) {
1249 		kprintf("Warning: vnode %p clean/cache_resolution "
1250 			"race detected\n", vp);
1251 		tsleep(vp, 0, "vclninv", 2);
1252 	}
1253 
1254 	/*
1255 	 * Check to see if the vnode is in use. If so we have to reference it
1256 	 * before we clean it out so that its count cannot fall to zero and
1257 	 * generate a race against ourselves to recycle it.
1258 	 */
1259 	active = (VREFCNT(vp) > 0);
1260 
1261 	/*
1262 	 * Clean out any buffers associated with the vnode and destroy its
1263 	 * object, if it has one.
1264 	 */
1265 	vinvalbuf(vp, V_SAVE, 0, 0);
1266 
1267 	/*
1268 	 * If purging an active vnode (typically during a forced unmount
1269 	 * or reboot), it must be closed and deactivated before being
1270 	 * reclaimed.  This isn't really all that safe, but what can
1271 	 * we do? XXX.
1272 	 *
1273 	 * Note that neither of these routines unlocks the vnode.
1274 	 */
1275 	if (active && (flags & DOCLOSE)) {
1276 		while ((n = vp->v_opencount) != 0) {
1277 			if (vp->v_writecount)
1278 				VOP_CLOSE(vp, FWRITE|FNONBLOCK, NULL);
1279 			else
1280 				VOP_CLOSE(vp, FNONBLOCK, NULL);
1281 			if (vp->v_opencount == n) {
1282 				kprintf("Warning: unable to force-close"
1283 				       " vnode %p\n", vp);
1284 				break;
1285 			}
1286 		}
1287 	}
1288 
1289 	/*
1290 	 * If the vnode has not been deactivated, deactivated it.  Deactivation
1291 	 * can create new buffers and VM pages so we have to call vinvalbuf()
1292 	 * again to make sure they all get flushed.
1293 	 *
1294 	 * This can occur if a file with a link count of 0 needs to be
1295 	 * truncated.
1296 	 *
1297 	 * If the vnode is already dead don't try to deactivate it.
1298 	 */
1299 	if ((vp->v_flag & VINACTIVE) == 0) {
1300 		vsetflags(vp, VINACTIVE);
1301 		if (vp->v_mount)
1302 			VOP_INACTIVE(vp);
1303 		vinvalbuf(vp, V_SAVE, 0, 0);
1304 	}
1305 
1306 	/*
1307 	 * If the vnode has an object, destroy it.
1308 	 */
1309 	while ((object = vp->v_object) != NULL) {
1310 		vm_object_hold(object);
1311 		if (object == vp->v_object)
1312 			break;
1313 		vm_object_drop(object);
1314 	}
1315 
1316 	if (object != NULL) {
1317 		if (object->ref_count == 0) {
1318 			if ((object->flags & OBJ_DEAD) == 0)
1319 				vm_object_terminate(object);
1320 			vm_object_drop(object);
1321 			vclrflags(vp, VOBJBUF);
1322 		} else {
1323 			vm_pager_deallocate(object);
1324 			vclrflags(vp, VOBJBUF);
1325 			vm_object_drop(object);
1326 		}
1327 	}
1328 	KKASSERT((vp->v_flag & VOBJBUF) == 0);
1329 
1330 	if (vp->v_flag & VOBJDIRTY)
1331 		vclrobjdirty(vp);
1332 
1333 	/*
1334 	 * Reclaim the vnode if not already dead.
1335 	 */
1336 	if (vp->v_mount && VOP_RECLAIM(vp))
1337 		panic("vclean: cannot reclaim");
1338 
1339 	/*
1340 	 * Done with purge, notify sleepers of the grim news.
1341 	 */
1342 	vp->v_ops = &dead_vnode_vops_p;
1343 	vn_gone(vp);
1344 	vp->v_tag = VT_NON;
1345 
1346 	/*
1347 	 * If we are destroying an active vnode, reactivate it now that
1348 	 * we have reassociated it with deadfs.  This prevents the system
1349 	 * from crashing on the vnode due to it being unexpectedly marked
1350 	 * as inactive or reclaimed.
1351 	 */
1352 	if (active && (flags & DOCLOSE)) {
1353 		vclrflags(vp, VINACTIVE | VRECLAIMED);
1354 	}
1355 }
1356 
1357 /*
1358  * Eliminate all activity associated with the requested vnode
1359  * and with all vnodes aliased to the requested vnode.
1360  *
1361  * The vnode must be referenced but should not be locked.
1362  */
1363 int
1364 vrevoke(struct vnode *vp, struct ucred *cred)
1365 {
1366 	struct vnode *vq;
1367 	struct vnode *vqn;
1368 	cdev_t dev;
1369 	int error;
1370 
1371 	/*
1372 	 * If the vnode has a device association, scrap all vnodes associated
1373 	 * with the device.  Don't let the device disappear on us while we
1374 	 * are scrapping the vnodes.
1375 	 *
1376 	 * The passed vp will probably show up in the list, do not VX lock
1377 	 * it twice!
1378 	 *
1379 	 * Releasing the vnode's rdev here can mess up specfs's call to
1380 	 * device close, so don't do it.  The vnode has been disassociated
1381 	 * and the device will be closed after the last ref on the related
1382 	 * fp goes away (if not still open by e.g. the kernel).
1383 	 */
1384 	if (vp->v_type != VCHR) {
1385 		error = fdrevoke(vp, DTYPE_VNODE, cred);
1386 		return (error);
1387 	}
1388 	if ((dev = vp->v_rdev) == NULL) {
1389 		return(0);
1390 	}
1391 	reference_dev(dev);
1392 	lwkt_gettoken(&spechash_token);
1393 
1394 restart:
1395 	vqn = SLIST_FIRST(&dev->si_hlist);
1396 	if (vqn)
1397 		vhold(vqn);
1398 	while ((vq = vqn) != NULL) {
1399 		if (VREFCNT(vq) > 0) {
1400 			vref(vq);
1401 			fdrevoke(vq, DTYPE_VNODE, cred);
1402 			/*v_release_rdev(vq);*/
1403 			vrele(vq);
1404 			if (vq->v_rdev != dev) {
1405 				vdrop(vq);
1406 				goto restart;
1407 			}
1408 		}
1409 		vqn = SLIST_NEXT(vq, v_cdevnext);
1410 		if (vqn)
1411 			vhold(vqn);
1412 		vdrop(vq);
1413 	}
1414 	lwkt_reltoken(&spechash_token);
1415 	dev_drevoke(dev);
1416 	release_dev(dev);
1417 	return (0);
1418 }
1419 
1420 /*
1421  * This is called when the object underlying a vnode is being destroyed,
1422  * such as in a remove().  Try to recycle the vnode immediately if the
1423  * only active reference is our reference.
1424  *
1425  * Directory vnodes in the namecache with children cannot be immediately
1426  * recycled because numerous VOP_N*() ops require them to be stable.
1427  *
1428  * To avoid recursive recycling from VOP_INACTIVE implemenetations this
1429  * function is a NOP if VRECLAIMED is already set.
1430  */
1431 int
1432 vrecycle(struct vnode *vp)
1433 {
1434 	if (VREFCNT(vp) <= 1 && (vp->v_flag & VRECLAIMED) == 0) {
1435 		if (cache_inval_vp_nonblock(vp))
1436 			return(0);
1437 		vgone_vxlocked(vp);
1438 		return (1);
1439 	}
1440 	return (0);
1441 }
1442 
1443 /*
1444  * Return the maximum I/O size allowed for strategy calls on VP.
1445  *
1446  * If vp is VCHR or VBLK we dive the device, otherwise we use
1447  * the vp's mount info.
1448  *
1449  * The returned value is clamped at MAXPHYS as most callers cannot use
1450  * buffers larger than that size.
1451  */
1452 int
1453 vmaxiosize(struct vnode *vp)
1454 {
1455 	int maxiosize;
1456 
1457 	if (vp->v_type == VBLK || vp->v_type == VCHR)
1458 		maxiosize = vp->v_rdev->si_iosize_max;
1459 	else
1460 		maxiosize = vp->v_mount->mnt_iosize_max;
1461 
1462 	if (maxiosize > MAXPHYS)
1463 		maxiosize = MAXPHYS;
1464 	return (maxiosize);
1465 }
1466 
1467 /*
1468  * Eliminate all activity associated with a vnode in preparation for
1469  * destruction.
1470  *
1471  * The vnode must be VX locked and refd and will remain VX locked and refd
1472  * on return.  This routine may be called with the vnode in any state, as
1473  * long as it is VX locked.  The vnode will be cleaned out and marked
1474  * VRECLAIMED but will not actually be reused until all existing refs and
1475  * holds go away.
1476  *
1477  * NOTE: This routine may be called on a vnode which has not yet been
1478  * already been deactivated (VOP_INACTIVE), or on a vnode which has
1479  * already been reclaimed.
1480  *
1481  * This routine is not responsible for placing us back on the freelist.
1482  * Instead, it happens automatically when the caller releases the VX lock
1483  * (assuming there aren't any other references).
1484  */
1485 void
1486 vgone_vxlocked(struct vnode *vp)
1487 {
1488 	/*
1489 	 * assert that the VX lock is held.  This is an absolute requirement
1490 	 * now for vgone_vxlocked() to be called.
1491 	 */
1492 	KKASSERT(lockinuse(&vp->v_lock));
1493 
1494 	/*
1495 	 * Clean out the filesystem specific data and set the VRECLAIMED
1496 	 * bit.  Also deactivate the vnode if necessary.
1497 	 *
1498 	 * The vnode should have automatically been removed from the syncer
1499 	 * list as syncer/dirty flags cleared during the cleaning.
1500 	 */
1501 	vclean_vxlocked(vp, DOCLOSE);
1502 
1503 	/*
1504 	 * Normally panic if the vnode is still dirty, unless we are doing
1505 	 * a forced unmount (tmpfs typically).
1506 	 */
1507 	if (vp->v_flag & VONWORKLST) {
1508 		if (vp->v_mount->mnt_kern_flag & MNTK_UNMOUNTF) {
1509 			/* force removal */
1510 			vn_syncer_remove(vp, 1);
1511 		} else {
1512 			panic("vp %p still dirty in vgone after flush", vp);
1513 		}
1514 	}
1515 
1516 	/*
1517 	 * Delete from old mount point vnode list, if on one.
1518 	 */
1519 	if (vp->v_mount != NULL) {
1520 		KKASSERT(vp->v_data == NULL);
1521 		insmntque(vp, NULL);
1522 	}
1523 
1524 	/*
1525 	 * If special device, remove it from special device alias list
1526 	 * if it is on one.  This should normally only occur if a vnode is
1527 	 * being revoked as the device should otherwise have been released
1528 	 * naturally.
1529 	 */
1530 	if ((vp->v_type == VBLK || vp->v_type == VCHR) && vp->v_rdev != NULL) {
1531 		v_release_rdev(vp);
1532 	}
1533 
1534 	/*
1535 	 * Set us to VBAD
1536 	 */
1537 	vp->v_type = VBAD;
1538 }
1539 
1540 /*
1541  * Lookup a vnode by device number.
1542  *
1543  * Returns non-zero and *vpp set to a vref'd vnode on success.
1544  * Returns zero on failure.
1545  */
1546 int
1547 vfinddev(cdev_t dev, enum vtype type, struct vnode **vpp)
1548 {
1549 	struct vnode *vp;
1550 
1551 	lwkt_gettoken(&spechash_token);
1552 	SLIST_FOREACH(vp, &dev->si_hlist, v_cdevnext) {
1553 		if (type == vp->v_type) {
1554 			*vpp = vp;
1555 			vref(vp);
1556 			lwkt_reltoken(&spechash_token);
1557 			return (1);
1558 		}
1559 	}
1560 	lwkt_reltoken(&spechash_token);
1561 	return (0);
1562 }
1563 
1564 /*
1565  * Calculate the total number of references to a special device.  This
1566  * routine may only be called for VBLK and VCHR vnodes since v_rdev is
1567  * an overloaded field.  Since udev2dev can now return NULL, we have
1568  * to check for a NULL v_rdev.
1569  */
1570 int
1571 count_dev(cdev_t dev)
1572 {
1573 	struct vnode *vp;
1574 	int count = 0;
1575 
1576 	if (SLIST_FIRST(&dev->si_hlist)) {
1577 		lwkt_gettoken(&spechash_token);
1578 		SLIST_FOREACH(vp, &dev->si_hlist, v_cdevnext) {
1579 			count += vp->v_opencount;
1580 		}
1581 		lwkt_reltoken(&spechash_token);
1582 	}
1583 	return(count);
1584 }
1585 
1586 int
1587 vcount(struct vnode *vp)
1588 {
1589 	if (vp->v_rdev == NULL)
1590 		return(0);
1591 	return(count_dev(vp->v_rdev));
1592 }
1593 
1594 /*
1595  * Initialize VMIO for a vnode.  This routine MUST be called before a
1596  * VFS can issue buffer cache ops on a vnode.  It is typically called
1597  * when a vnode is initialized from its inode.
1598  */
1599 int
1600 vinitvmio(struct vnode *vp, off_t filesize, int blksize, int boff)
1601 {
1602 	vm_object_t object;
1603 	int error = 0;
1604 
1605 	object = vp->v_object;
1606 	if (object) {
1607 		vm_object_hold(object);
1608 		KKASSERT(vp->v_object == object);
1609 	}
1610 
1611 	if (object == NULL) {
1612 		object = vnode_pager_alloc(vp, filesize, 0, 0, blksize, boff);
1613 
1614 		/*
1615 		 * Dereference the reference we just created.  This assumes
1616 		 * that the object is associated with the vp.  Allow it to
1617 		 * have zero refs.  It cannot be destroyed as long as it
1618 		 * is associated with the vnode.
1619 		 */
1620 		vm_object_hold(object);
1621 		atomic_add_int(&object->ref_count, -1);
1622 		vrele(vp);
1623 	} else {
1624 		KKASSERT((object->flags & OBJ_DEAD) == 0);
1625 	}
1626 	KASSERT(vp->v_object != NULL, ("vinitvmio: NULL object"));
1627 	vsetflags(vp, VOBJBUF);
1628 	vm_object_drop(object);
1629 
1630 	return (error);
1631 }
1632 
1633 
1634 /*
1635  * Print out a description of a vnode.
1636  */
1637 static char *typename[] =
1638 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
1639 
1640 void
1641 vprint(char *label, struct vnode *vp)
1642 {
1643 	char buf[96];
1644 
1645 	if (label != NULL)
1646 		kprintf("%s: %p: ", label, (void *)vp);
1647 	else
1648 		kprintf("%p: ", (void *)vp);
1649 	kprintf("type %s, refcnt %08x, writecount %d, holdcnt %d,",
1650 		typename[vp->v_type],
1651 		vp->v_refcnt, vp->v_writecount, vp->v_auxrefs);
1652 	buf[0] = '\0';
1653 	if (vp->v_flag & VROOT)
1654 		strcat(buf, "|VROOT");
1655 	if (vp->v_flag & VPFSROOT)
1656 		strcat(buf, "|VPFSROOT");
1657 	if (vp->v_flag & VTEXT)
1658 		strcat(buf, "|VTEXT");
1659 	if (vp->v_flag & VSYSTEM)
1660 		strcat(buf, "|VSYSTEM");
1661 	if (vp->v_flag & VOBJBUF)
1662 		strcat(buf, "|VOBJBUF");
1663 	if (buf[0] != '\0')
1664 		kprintf(" flags (%s)", &buf[1]);
1665 	if (vp->v_data == NULL) {
1666 		kprintf("\n");
1667 	} else {
1668 		kprintf("\n\t");
1669 		VOP_PRINT(vp);
1670 	}
1671 }
1672 
1673 /*
1674  * Do the usual access checking.
1675  * file_mode, uid and gid are from the vnode in question,
1676  * while acc_mode and cred are from the VOP_ACCESS parameter list
1677  */
1678 int
1679 vaccess(enum vtype type, mode_t file_mode, uid_t uid, gid_t gid,
1680     mode_t acc_mode, struct ucred *cred)
1681 {
1682 	mode_t mask;
1683 	int ismember;
1684 
1685 	/*
1686 	 * Super-user always gets read/write access, but execute access depends
1687 	 * on at least one execute bit being set.
1688 	 */
1689 	if (priv_check_cred(cred, PRIV_ROOT, 0) == 0) {
1690 		if ((acc_mode & VEXEC) && type != VDIR &&
1691 		    (file_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)
1692 			return (EACCES);
1693 		return (0);
1694 	}
1695 
1696 	mask = 0;
1697 
1698 	/* Otherwise, check the owner. */
1699 	if (cred->cr_uid == uid) {
1700 		if (acc_mode & VEXEC)
1701 			mask |= S_IXUSR;
1702 		if (acc_mode & VREAD)
1703 			mask |= S_IRUSR;
1704 		if (acc_mode & VWRITE)
1705 			mask |= S_IWUSR;
1706 		return ((file_mode & mask) == mask ? 0 : EACCES);
1707 	}
1708 
1709 	/* Otherwise, check the groups. */
1710 	ismember = groupmember(gid, cred);
1711 	if (cred->cr_svgid == gid || ismember) {
1712 		if (acc_mode & VEXEC)
1713 			mask |= S_IXGRP;
1714 		if (acc_mode & VREAD)
1715 			mask |= S_IRGRP;
1716 		if (acc_mode & VWRITE)
1717 			mask |= S_IWGRP;
1718 		return ((file_mode & mask) == mask ? 0 : EACCES);
1719 	}
1720 
1721 	/* Otherwise, check everyone else. */
1722 	if (acc_mode & VEXEC)
1723 		mask |= S_IXOTH;
1724 	if (acc_mode & VREAD)
1725 		mask |= S_IROTH;
1726 	if (acc_mode & VWRITE)
1727 		mask |= S_IWOTH;
1728 	return ((file_mode & mask) == mask ? 0 : EACCES);
1729 }
1730 
1731 #ifdef DDB
1732 #include <ddb/ddb.h>
1733 
1734 static int db_show_locked_vnodes(struct mount *mp, void *data);
1735 
1736 /*
1737  * List all of the locked vnodes in the system.
1738  * Called when debugging the kernel.
1739  */
1740 DB_SHOW_COMMAND(lockedvnodes, lockedvnodes)
1741 {
1742 	kprintf("Locked vnodes\n");
1743 	mountlist_scan(db_show_locked_vnodes, NULL,
1744 			MNTSCAN_FORWARD|MNTSCAN_NOBUSY);
1745 }
1746 
1747 static int
1748 db_show_locked_vnodes(struct mount *mp, void *data __unused)
1749 {
1750 	struct vnode *vp;
1751 
1752 	TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
1753 		if (vn_islocked(vp))
1754 			vprint(NULL, vp);
1755 	}
1756 	return(0);
1757 }
1758 #endif
1759 
1760 /*
1761  * Top level filesystem related information gathering.
1762  */
1763 static int	sysctl_ovfs_conf (SYSCTL_HANDLER_ARGS);
1764 
1765 static int
1766 vfs_sysctl(SYSCTL_HANDLER_ARGS)
1767 {
1768 	int *name = (int *)arg1 - 1;	/* XXX */
1769 	u_int namelen = arg2 + 1;	/* XXX */
1770 	struct vfsconf *vfsp;
1771 	int maxtypenum;
1772 
1773 #if 1 || defined(COMPAT_PRELITE2)
1774 	/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
1775 	if (namelen == 1)
1776 		return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
1777 #endif
1778 
1779 #ifdef notyet
1780 	/* all sysctl names at this level are at least name and field */
1781 	if (namelen < 2)
1782 		return (ENOTDIR);		/* overloaded */
1783 	if (name[0] != VFS_GENERIC) {
1784 		vfsp = vfsconf_find_by_typenum(name[0]);
1785 		if (vfsp == NULL)
1786 			return (EOPNOTSUPP);
1787 		return ((*vfsp->vfc_vfsops->vfs_sysctl)(&name[1], namelen - 1,
1788 		    oldp, oldlenp, newp, newlen, p));
1789 	}
1790 #endif
1791 	switch (name[1]) {
1792 	case VFS_MAXTYPENUM:
1793 		if (namelen != 2)
1794 			return (ENOTDIR);
1795 		maxtypenum = vfsconf_get_maxtypenum();
1796 		return (SYSCTL_OUT(req, &maxtypenum, sizeof(maxtypenum)));
1797 	case VFS_CONF:
1798 		if (namelen != 3)
1799 			return (ENOTDIR);	/* overloaded */
1800 		vfsp = vfsconf_find_by_typenum(name[2]);
1801 		if (vfsp == NULL)
1802 			return (EOPNOTSUPP);
1803 		return (SYSCTL_OUT(req, vfsp, sizeof *vfsp));
1804 	}
1805 	return (EOPNOTSUPP);
1806 }
1807 
1808 SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD, vfs_sysctl,
1809 	"Generic filesystem");
1810 
1811 #if 1 || defined(COMPAT_PRELITE2)
1812 
1813 static int
1814 sysctl_ovfs_conf_iter(struct vfsconf *vfsp, void *data)
1815 {
1816 	int error;
1817 	struct ovfsconf ovfs;
1818 	struct sysctl_req *req = (struct sysctl_req*) data;
1819 
1820 	bzero(&ovfs, sizeof(ovfs));
1821 	ovfs.vfc_vfsops = vfsp->vfc_vfsops;	/* XXX used as flag */
1822 	strcpy(ovfs.vfc_name, vfsp->vfc_name);
1823 	ovfs.vfc_index = vfsp->vfc_typenum;
1824 	ovfs.vfc_refcount = vfsp->vfc_refcount;
1825 	ovfs.vfc_flags = vfsp->vfc_flags;
1826 	error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
1827 	if (error)
1828 		return error; /* abort iteration with error code */
1829 	else
1830 		return 0; /* continue iterating with next element */
1831 }
1832 
1833 static int
1834 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
1835 {
1836 	return vfsconf_each(sysctl_ovfs_conf_iter, (void*)req);
1837 }
1838 
1839 #endif /* 1 || COMPAT_PRELITE2 */
1840 
1841 /*
1842  * Check to see if a filesystem is mounted on a block device.
1843  */
1844 int
1845 vfs_mountedon(struct vnode *vp)
1846 {
1847 	cdev_t dev;
1848 
1849 	if ((dev = vp->v_rdev) == NULL) {
1850 /*		if (vp->v_type != VBLK)
1851 			dev = get_dev(vp->v_uminor, vp->v_umajor); */
1852 	}
1853 	if (dev != NULL && dev->si_mountpoint)
1854 		return (EBUSY);
1855 	return (0);
1856 }
1857 
1858 /*
1859  * Unmount all filesystems. The list is traversed in reverse order
1860  * of mounting to avoid dependencies.
1861  *
1862  * We want the umountall to be able to break out of its loop if a
1863  * failure occurs, after scanning all possible mounts, so the callback
1864  * returns 0 on error.
1865  *
1866  * NOTE: Do not call mountlist_remove(mp) on error any more, this will
1867  *	 confuse mountlist_scan()'s unbusy check.
1868  */
1869 static int vfs_umountall_callback(struct mount *mp, void *data);
1870 
1871 void
1872 vfs_unmountall(int halting)
1873 {
1874 	int count;
1875 
1876 	do {
1877 		count = mountlist_scan(vfs_umountall_callback, &halting,
1878 				       MNTSCAN_REVERSE|MNTSCAN_NOBUSY);
1879 	} while (count);
1880 }
1881 
1882 static
1883 int
1884 vfs_umountall_callback(struct mount *mp, void *data)
1885 {
1886 	int error;
1887 	int halting = *(int *)data;
1888 
1889 	/*
1890 	 * NOTE: When halting, dounmount will disconnect but leave
1891 	 *	 certain mount points intact.  e.g. devfs.
1892 	 */
1893 	error = dounmount(mp, MNT_FORCE, halting);
1894 	if (error) {
1895 		kprintf("unmount of filesystem mounted from %s failed (",
1896 			mp->mnt_stat.f_mntfromname);
1897 		if (error == EBUSY)
1898 			kprintf("BUSY)\n");
1899 		else
1900 			kprintf("%d)\n", error);
1901 		return 0;
1902 	} else {
1903 		return 1;
1904 	}
1905 }
1906 
1907 /*
1908  * Checks the mount flags for parameter mp and put the names comma-separated
1909  * into a string buffer buf with a size limit specified by len.
1910  *
1911  * It returns the number of bytes written into buf, and (*errorp) will be
1912  * set to 0, EINVAL (if passed length is 0), or ENOSPC (supplied buffer was
1913  * not large enough).  The buffer will be 0-terminated if len was not 0.
1914  */
1915 size_t
1916 vfs_flagstostr(int flags, const struct mountctl_opt *optp,
1917 	       char *buf, size_t len, int *errorp)
1918 {
1919 	static const struct mountctl_opt optnames[] = {
1920 		{ MNT_RDONLY,           "read-only" },
1921 		{ MNT_SYNCHRONOUS,      "synchronous" },
1922 		{ MNT_NOEXEC,           "noexec" },
1923 		{ MNT_NOSUID,           "nosuid" },
1924 		{ MNT_NODEV,            "nodev" },
1925 		{ MNT_AUTOMOUNTED,      "automounted" },
1926 		{ MNT_ASYNC,            "asynchronous" },
1927 		{ MNT_SUIDDIR,          "suiddir" },
1928 		{ MNT_SOFTDEP,          "soft-updates" },
1929 		{ MNT_NOSYMFOLLOW,      "nosymfollow" },
1930 		{ MNT_TRIM,             "trim" },
1931 		{ MNT_NOATIME,          "noatime" },
1932 		{ MNT_NOCLUSTERR,       "noclusterr" },
1933 		{ MNT_NOCLUSTERW,       "noclusterw" },
1934 		{ MNT_EXRDONLY,         "NFS read-only" },
1935 		{ MNT_EXPORTED,         "NFS exported" },
1936 		/* Remaining NFS flags could come here */
1937 		{ MNT_LOCAL,            "local" },
1938 		{ MNT_QUOTA,            "with-quotas" },
1939 		/* { MNT_ROOTFS,           "rootfs" }, */
1940 		/* { MNT_IGNORE,           "ignore" }, */
1941 		{ 0,			NULL}
1942 	};
1943 	int bwritten;
1944 	int bleft;
1945 	int optlen;
1946 	int actsize;
1947 
1948 	*errorp = 0;
1949 	bwritten = 0;
1950 	bleft = len - 1;	/* leave room for trailing \0 */
1951 
1952 	/*
1953 	 * Checks the size of the string. If it contains
1954 	 * any data, then we will append the new flags to
1955 	 * it.
1956 	 */
1957 	actsize = strlen(buf);
1958 	if (actsize > 0)
1959 		buf += actsize;
1960 
1961 	/* Default flags if no flags passed */
1962 	if (optp == NULL)
1963 		optp = optnames;
1964 
1965 	if (bleft < 0) {	/* degenerate case, 0-length buffer */
1966 		*errorp = EINVAL;
1967 		return(0);
1968 	}
1969 
1970 	for (; flags && optp->o_opt; ++optp) {
1971 		if ((flags & optp->o_opt) == 0)
1972 			continue;
1973 		optlen = strlen(optp->o_name);
1974 		if (bwritten || actsize > 0) {
1975 			if (bleft < 2) {
1976 				*errorp = ENOSPC;
1977 				break;
1978 			}
1979 			buf[bwritten++] = ',';
1980 			buf[bwritten++] = ' ';
1981 			bleft -= 2;
1982 		}
1983 		if (bleft < optlen) {
1984 			*errorp = ENOSPC;
1985 			break;
1986 		}
1987 		bcopy(optp->o_name, buf + bwritten, optlen);
1988 		bwritten += optlen;
1989 		bleft -= optlen;
1990 		flags &= ~optp->o_opt;
1991 	}
1992 
1993 	/*
1994 	 * Space already reserved for trailing \0
1995 	 */
1996 	buf[bwritten] = 0;
1997 	return (bwritten);
1998 }
1999 
2000 /*
2001  * Build hash lists of net addresses and hang them off the mount point.
2002  * Called by ufs_mount() to set up the lists of export addresses.
2003  */
2004 static int
2005 vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
2006 		const struct export_args *argp)
2007 {
2008 	struct netcred *np;
2009 	struct radix_node_head *rnh;
2010 	int i;
2011 	struct radix_node *rn;
2012 	struct sockaddr *saddr, *smask = NULL;
2013 	int error;
2014 
2015 	if (argp->ex_addrlen == 0) {
2016 		if (mp->mnt_flag & MNT_DEFEXPORTED)
2017 			return (EPERM);
2018 		np = &nep->ne_defexported;
2019 		np->netc_exflags = argp->ex_flags;
2020 		np->netc_anon = argp->ex_anon;
2021 		np->netc_anon.cr_ref = 1;
2022 		mp->mnt_flag |= MNT_DEFEXPORTED;
2023 		return (0);
2024 	}
2025 
2026 	if (argp->ex_addrlen < 0 || argp->ex_addrlen > MLEN)
2027 		return (EINVAL);
2028 	if (argp->ex_masklen < 0 || argp->ex_masklen > MLEN)
2029 		return (EINVAL);
2030 
2031 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
2032 	np = (struct netcred *)kmalloc(i, M_NETCRED, M_WAITOK | M_ZERO);
2033 	saddr = (struct sockaddr *) (np + 1);
2034 	if ((error = copyin(argp->ex_addr, (caddr_t) saddr, argp->ex_addrlen)))
2035 		goto out;
2036 	if (saddr->sa_len > argp->ex_addrlen)
2037 		saddr->sa_len = argp->ex_addrlen;
2038 	if (argp->ex_masklen) {
2039 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
2040 		error = copyin(argp->ex_mask, (caddr_t)smask, argp->ex_masklen);
2041 		if (error)
2042 			goto out;
2043 		if (smask->sa_len > argp->ex_masklen)
2044 			smask->sa_len = argp->ex_masklen;
2045 	}
2046 	NE_LOCK(nep);
2047 	if (nep->ne_maskhead == NULL) {
2048 		if (!rn_inithead((void **)&nep->ne_maskhead, NULL, 0)) {
2049 			error = ENOBUFS;
2050 			goto out;
2051 		}
2052 	}
2053 	if ((rnh = vfs_create_addrlist_af(saddr->sa_family, nep)) == NULL) {
2054 		error = ENOBUFS;
2055 		goto out;
2056 	}
2057 	rn = (*rnh->rnh_addaddr)((char *)saddr, (char *)smask, rnh,
2058 				 np->netc_rnodes);
2059 	NE_UNLOCK(nep);
2060 	if (rn == NULL || np != (struct netcred *)rn) {	/* already exists */
2061 		error = EPERM;
2062 		goto out;
2063 	}
2064 	np->netc_exflags = argp->ex_flags;
2065 	np->netc_anon = argp->ex_anon;
2066 	np->netc_anon.cr_ref = 1;
2067 	return (0);
2068 
2069 out:
2070 	kfree(np, M_NETCRED);
2071 	return (error);
2072 }
2073 
2074 /*
2075  * Free netcred structures installed in the netexport
2076  */
2077 static int
2078 vfs_free_netcred(struct radix_node *rn, void *w)
2079 {
2080 	struct radix_node_head *rnh = (struct radix_node_head *)w;
2081 
2082 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
2083 	kfree(rn, M_NETCRED);
2084 
2085 	return (0);
2086 }
2087 
2088 /*
2089  * callback to free an element of the mask table installed in the
2090  * netexport.  These may be created indirectly and are not netcred
2091  * structures.
2092  */
2093 static int
2094 vfs_free_netcred_mask(struct radix_node *rn, void *w)
2095 {
2096 	struct radix_node_head *rnh = (struct radix_node_head *)w;
2097 
2098 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
2099 	kfree(rn, M_RTABLE);
2100 
2101 	return (0);
2102 }
2103 
2104 static struct radix_node_head *
2105 vfs_create_addrlist_af(int af, struct netexport *nep)
2106 {
2107 	struct radix_node_head *rnh = NULL;
2108 #if defined(INET) || defined(INET6)
2109 	struct radix_node_head *maskhead = nep->ne_maskhead;
2110 	int off;
2111 #endif
2112 
2113 	NE_ASSERT_LOCKED(nep);
2114 	KKASSERT(maskhead != NULL);
2115 	switch (af) {
2116 #ifdef INET
2117 	case AF_INET:
2118 		if ((rnh = nep->ne_inethead) == NULL) {
2119 			off = offsetof(struct sockaddr_in, sin_addr) << 3;
2120 			if (!rn_inithead((void **)&rnh, maskhead, off))
2121 				return (NULL);
2122 			nep->ne_inethead = rnh;
2123 		}
2124 		break;
2125 #endif
2126 #ifdef INET6
2127 	case AF_INET6:
2128 		if ((rnh = nep->ne_inet6head) == NULL) {
2129 			off = offsetof(struct sockaddr_in6, sin6_addr) << 3;
2130 			if (!rn_inithead((void **)&rnh, maskhead, off))
2131 				return (NULL);
2132 			nep->ne_inet6head = rnh;
2133 		}
2134 		break;
2135 #endif
2136 	}
2137 	return (rnh);
2138 }
2139 
2140 /*
2141  * helper function for freeing netcred elements
2142  */
2143 static void
2144 vfs_free_addrlist_af(struct radix_node_head **prnh)
2145 {
2146 	struct radix_node_head *rnh = *prnh;
2147 
2148 	(*rnh->rnh_walktree) (rnh, vfs_free_netcred, rnh);
2149 	kfree(rnh, M_RTABLE);
2150 	*prnh = NULL;
2151 }
2152 
2153 /*
2154  * helper function for freeing mask elements
2155  */
2156 static void
2157 vfs_free_addrlist_masks(struct radix_node_head **prnh)
2158 {
2159 	struct radix_node_head *rnh = *prnh;
2160 
2161 	(*rnh->rnh_walktree) (rnh, vfs_free_netcred_mask, rnh);
2162 	kfree(rnh, M_RTABLE);
2163 	*prnh = NULL;
2164 }
2165 
2166 /*
2167  * Free the net address hash lists that are hanging off the mount points.
2168  */
2169 static void
2170 vfs_free_addrlist(struct netexport *nep)
2171 {
2172 	NE_LOCK(nep);
2173 	if (nep->ne_inethead != NULL)
2174 		vfs_free_addrlist_af(&nep->ne_inethead);
2175 	if (nep->ne_inet6head != NULL)
2176 		vfs_free_addrlist_af(&nep->ne_inet6head);
2177 	if (nep->ne_maskhead)
2178 		vfs_free_addrlist_masks(&nep->ne_maskhead);
2179 	NE_UNLOCK(nep);
2180 }
2181 
2182 int
2183 vfs_export(struct mount *mp, struct netexport *nep,
2184 	   const struct export_args *argp)
2185 {
2186 	int error;
2187 
2188 	if (argp->ex_flags & MNT_DELEXPORT) {
2189 		if (mp->mnt_flag & MNT_EXPUBLIC) {
2190 			vfs_setpublicfs(NULL, NULL, NULL);
2191 			mp->mnt_flag &= ~MNT_EXPUBLIC;
2192 		}
2193 		vfs_free_addrlist(nep);
2194 		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
2195 	}
2196 	if (argp->ex_flags & MNT_EXPORTED) {
2197 		if (argp->ex_flags & MNT_EXPUBLIC) {
2198 			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
2199 				return (error);
2200 			mp->mnt_flag |= MNT_EXPUBLIC;
2201 		}
2202 		if ((error = vfs_hang_addrlist(mp, nep, argp)))
2203 			return (error);
2204 		mp->mnt_flag |= MNT_EXPORTED;
2205 	}
2206 	return (0);
2207 }
2208 
2209 
2210 /*
2211  * Set the publicly exported filesystem (WebNFS). Currently, only
2212  * one public filesystem is possible in the spec (RFC 2054 and 2055)
2213  */
2214 int
2215 vfs_setpublicfs(struct mount *mp, struct netexport *nep,
2216 		const struct export_args *argp)
2217 {
2218 	int error;
2219 	struct vnode *rvp;
2220 	char *cp;
2221 
2222 	/*
2223 	 * mp == NULL -> invalidate the current info, the FS is
2224 	 * no longer exported. May be called from either vfs_export
2225 	 * or unmount, so check if it hasn't already been done.
2226 	 */
2227 	if (mp == NULL) {
2228 		if (nfs_pub.np_valid) {
2229 			nfs_pub.np_valid = 0;
2230 			if (nfs_pub.np_index != NULL) {
2231 				kfree(nfs_pub.np_index, M_TEMP);
2232 				nfs_pub.np_index = NULL;
2233 			}
2234 		}
2235 		return (0);
2236 	}
2237 
2238 	/*
2239 	 * Only one allowed at a time.
2240 	 */
2241 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
2242 		return (EBUSY);
2243 
2244 	/*
2245 	 * Get real filehandle for root of exported FS.
2246 	 */
2247 	bzero((caddr_t)&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
2248 	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
2249 
2250 	if ((error = VFS_ROOT(mp, &rvp)))
2251 		return (error);
2252 
2253 	if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
2254 		return (error);
2255 
2256 	vput(rvp);
2257 
2258 	/*
2259 	 * If an indexfile was specified, pull it in.
2260 	 */
2261 	if (argp->ex_indexfile != NULL) {
2262 		int namelen;
2263 
2264 		error = vn_get_namelen(rvp, &namelen);
2265 		if (error)
2266 			return (error);
2267 		nfs_pub.np_index = kmalloc(namelen, M_TEMP, M_WAITOK);
2268 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
2269 		    namelen, NULL);
2270 		if (!error) {
2271 			/*
2272 			 * Check for illegal filenames.
2273 			 */
2274 			for (cp = nfs_pub.np_index; *cp; cp++) {
2275 				if (*cp == '/') {
2276 					error = EINVAL;
2277 					break;
2278 				}
2279 			}
2280 		}
2281 		if (error) {
2282 			kfree(nfs_pub.np_index, M_TEMP);
2283 			return (error);
2284 		}
2285 	}
2286 
2287 	nfs_pub.np_mount = mp;
2288 	nfs_pub.np_valid = 1;
2289 	return (0);
2290 }
2291 
2292 struct netcred *
2293 vfs_export_lookup(struct mount *mp, struct netexport *nep,
2294 		struct sockaddr *nam)
2295 {
2296 	struct netcred *np;
2297 	struct radix_node_head *rnh;
2298 	struct sockaddr *saddr;
2299 
2300 	np = NULL;
2301 	if (mp->mnt_flag & MNT_EXPORTED) {
2302 		/*
2303 		 * Lookup in the export list first.
2304 		 */
2305 		NE_LOCK(nep);
2306 		if (nam != NULL) {
2307 			saddr = nam;
2308 			switch (saddr->sa_family) {
2309 #ifdef INET
2310 			case AF_INET:
2311 				rnh = nep->ne_inethead;
2312 				break;
2313 #endif
2314 #ifdef INET6
2315 			case AF_INET6:
2316 				rnh = nep->ne_inet6head;
2317 				break;
2318 #endif
2319 			default:
2320 				rnh = NULL;
2321 			}
2322 			if (rnh != NULL) {
2323 				np = (struct netcred *)
2324 					(*rnh->rnh_matchaddr)((char *)saddr,
2325 							      rnh);
2326 				if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
2327 					np = NULL;
2328 			}
2329 		}
2330 		NE_UNLOCK(nep);
2331 		/*
2332 		 * If no address match, use the default if it exists.
2333 		 */
2334 		if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
2335 			np = &nep->ne_defexported;
2336 	}
2337 	return (np);
2338 }
2339 
2340 /*
2341  * perform msync on all vnodes under a mount point.  The mount point must
2342  * be locked.  This code is also responsible for lazy-freeing unreferenced
2343  * vnodes whos VM objects no longer contain pages.
2344  *
2345  * NOTE: MNT_WAIT still skips vnodes in the VXLOCK state.
2346  *
2347  * NOTE: XXX VOP_PUTPAGES and friends requires that the vnode be locked,
2348  * but vnode_pager_putpages() doesn't lock the vnode.  We have to do it
2349  * way up in this high level function.
2350  */
2351 static int vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data);
2352 static int vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data);
2353 
2354 void
2355 vfs_msync(struct mount *mp, int flags)
2356 {
2357 	int vmsc_flags;
2358 
2359 	/*
2360 	 * tmpfs sets this flag to prevent msync(), sync, and the
2361 	 * filesystem periodic syncer from trying to flush VM pages
2362 	 * to swap.  Only pure memory pressure flushes tmpfs VM pages
2363 	 * to swap.
2364 	 */
2365 	if (mp->mnt_kern_flag & MNTK_NOMSYNC)
2366 		return;
2367 
2368 	/*
2369 	 * Ok, scan the vnodes for work.  If the filesystem is using the
2370 	 * syncer thread feature we can use vsyncscan() instead of
2371 	 * vmntvnodescan(), which is much faster.
2372 	 */
2373 	vmsc_flags = VMSC_GETVP;
2374 	if (flags != MNT_WAIT)
2375 		vmsc_flags |= VMSC_NOWAIT;
2376 
2377 	if (mp->mnt_kern_flag & MNTK_THR_SYNC) {
2378 		vsyncscan(mp, vmsc_flags, vfs_msync_scan2,
2379 			  (void *)(intptr_t)flags);
2380 	} else {
2381 		vmntvnodescan(mp, vmsc_flags,
2382 			      vfs_msync_scan1, vfs_msync_scan2,
2383 			      (void *)(intptr_t)flags);
2384 	}
2385 }
2386 
2387 /*
2388  * scan1 is a fast pre-check.  There could be hundreds of thousands of
2389  * vnodes, we cannot afford to do anything heavy weight until we have a
2390  * fairly good indication that there is work to do.
2391  */
2392 static
2393 int
2394 vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data)
2395 {
2396 	int flags = (int)(intptr_t)data;
2397 
2398 	if ((vp->v_flag & VRECLAIMED) == 0) {
2399 		if (vp->v_auxrefs == 0 && VREFCNT(vp) <= 0 &&
2400 		    vp->v_object) {
2401 			return(0);	/* call scan2 */
2402 		}
2403 		if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
2404 		    (vp->v_flag & VOBJDIRTY) &&
2405 		    (flags == MNT_WAIT || vn_islocked(vp) == 0)) {
2406 			return(0);	/* call scan2 */
2407 		}
2408 	}
2409 
2410 	/*
2411 	 * do not call scan2, continue the loop
2412 	 */
2413 	return(-1);
2414 }
2415 
2416 /*
2417  * This callback is handed a locked vnode.
2418  */
2419 static
2420 int
2421 vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data)
2422 {
2423 	vm_object_t obj;
2424 	int flags = (int)(intptr_t)data;
2425 
2426 	if (vp->v_flag & VRECLAIMED)
2427 		return(0);
2428 
2429 	if ((mp->mnt_flag & MNT_RDONLY) == 0 && (vp->v_flag & VOBJDIRTY)) {
2430 		if ((obj = vp->v_object) != NULL) {
2431 			vm_object_page_clean(obj, 0, 0,
2432 			 flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
2433 		}
2434 	}
2435 	return(0);
2436 }
2437 
2438 /*
2439  * Wake up anyone interested in vp because it is being revoked.
2440  */
2441 void
2442 vn_gone(struct vnode *vp)
2443 {
2444 	lwkt_gettoken(&vp->v_token);
2445 	KNOTE(&vp->v_pollinfo.vpi_kqinfo.ki_note, NOTE_REVOKE);
2446 	lwkt_reltoken(&vp->v_token);
2447 }
2448 
2449 /*
2450  * extract the cdev_t from a VBLK or VCHR.  The vnode must have been opened
2451  * (or v_rdev might be NULL).
2452  */
2453 cdev_t
2454 vn_todev(struct vnode *vp)
2455 {
2456 	if (vp->v_type != VBLK && vp->v_type != VCHR)
2457 		return (NULL);
2458 	KKASSERT(vp->v_rdev != NULL);
2459 	return (vp->v_rdev);
2460 }
2461 
2462 /*
2463  * Check if vnode represents a disk device.  The vnode does not need to be
2464  * opened.
2465  *
2466  * MPALMOSTSAFE
2467  */
2468 int
2469 vn_isdisk(struct vnode *vp, int *errp)
2470 {
2471 	cdev_t dev;
2472 
2473 	if (vp->v_type != VCHR) {
2474 		if (errp != NULL)
2475 			*errp = ENOTBLK;
2476 		return (0);
2477 	}
2478 
2479 	dev = vp->v_rdev;
2480 
2481 	if (dev == NULL) {
2482 		if (errp != NULL)
2483 			*errp = ENXIO;
2484 		return (0);
2485 	}
2486 	if (dev_is_good(dev) == 0) {
2487 		if (errp != NULL)
2488 			*errp = ENXIO;
2489 		return (0);
2490 	}
2491 	if ((dev_dflags(dev) & D_DISK) == 0) {
2492 		if (errp != NULL)
2493 			*errp = ENOTBLK;
2494 		return (0);
2495 	}
2496 	if (errp != NULL)
2497 		*errp = 0;
2498 	return (1);
2499 }
2500 
2501 int
2502 vn_get_namelen(struct vnode *vp, int *namelen)
2503 {
2504 	int error;
2505 	register_t retval[2];
2506 
2507 	error = VOP_PATHCONF(vp, _PC_NAME_MAX, retval);
2508 	if (error)
2509 		return (error);
2510 	*namelen = (int)retval[0];
2511 	return (0);
2512 }
2513 
2514 int
2515 vop_write_dirent(int *error, struct uio *uio, ino_t d_ino, uint8_t d_type,
2516 		uint16_t d_namlen, const char *d_name)
2517 {
2518 	struct dirent *dp;
2519 	size_t len;
2520 
2521 	len = _DIRENT_RECLEN(d_namlen);
2522 	if (len > uio->uio_resid)
2523 		return(1);
2524 
2525 	dp = kmalloc(len, M_TEMP, M_WAITOK | M_ZERO);
2526 
2527 	dp->d_ino = d_ino;
2528 	dp->d_namlen = d_namlen;
2529 	dp->d_type = d_type;
2530 	bcopy(d_name, dp->d_name, d_namlen);
2531 
2532 	*error = uiomove((caddr_t)dp, len, uio);
2533 
2534 	kfree(dp, M_TEMP);
2535 
2536 	return(0);
2537 }
2538 
2539 void
2540 vn_mark_atime(struct vnode *vp, struct thread *td)
2541 {
2542 	struct proc *p = td->td_proc;
2543 	struct ucred *cred = p ? p->p_ucred : proc0.p_ucred;
2544 
2545 	if ((vp->v_mount->mnt_flag & (MNT_NOATIME | MNT_RDONLY)) == 0) {
2546 		VOP_MARKATIME(vp, cred);
2547 	}
2548 }
2549 
2550 /*
2551  * Calculate the number of entries in an inode-related chained hash table.
2552  * With today's memory sizes, maxvnodes can wind up being a very large
2553  * number.  There is no reason to waste memory, so tolerate some stacking.
2554  */
2555 int
2556 vfs_inodehashsize(void)
2557 {
2558 	int hsize;
2559 
2560 	hsize = 32;
2561 	while (hsize < maxvnodes)
2562 		hsize <<= 1;
2563 	while (hsize > maxvnodes * 2)
2564 		hsize >>= 1;		/* nominal 2x stacking */
2565 
2566 	if (maxvnodes > 1024 * 1024)
2567 		hsize >>= 1;		/* nominal 8x stacking */
2568 
2569 	if (maxvnodes > 128 * 1024)
2570 		hsize >>= 1;		/* nominal 4x stacking */
2571 
2572 	if (hsize < 16)
2573 		hsize = 16;
2574 
2575 	return hsize;
2576 }
2577