xref: /dragonfly/sys/kern/vfs_subr.c (revision 38b5d46c)
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 
87 #include <netinet/in.h>
88 
89 static MALLOC_DEFINE(M_NETADDR, "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, which is capped on 32 bit
165 	 * systems, to ~80K vnodes or so.
166 	 *
167 	 * WARNING!  For machines with 64-256M of ram we have to be sure
168 	 *	     that the default limit scales down well due to HAMMER
169 	 *	     taking up significantly more memory per-vnode vs UFS.
170 	 *	     We want around ~5800 on a 128M machine.
171 	 */
172 	factor1 = 25 * (sizeof(struct vm_object) + sizeof(struct vnode));
173 	factor2 = 30 * (sizeof(struct vm_object) + sizeof(struct vnode));
174 	maxvnodes = imin((int64_t)vmstats.v_page_count * PAGE_SIZE / factor1,
175 			 KvaSize / factor2);
176 	maxvnodes = imax(maxvnodes, maxproc * 8);
177 
178 	lwkt_token_init(&spechash_token, "spechash");
179 }
180 
181 /*
182  * Knob to control the precision of file timestamps:
183  *
184  *   0 = seconds only; nanoseconds zeroed.
185  *   1 = seconds and nanoseconds, accurate within 1/HZ.
186  *   2 = seconds and nanoseconds, truncated to microseconds.
187  * >=3 = seconds and nanoseconds, maximum precision.
188  */
189 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
190 
191 static int timestamp_precision = TSP_SEC;
192 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
193 		&timestamp_precision, 0, "Precision of file timestamps");
194 
195 /*
196  * Get a current timestamp.
197  *
198  * MPSAFE
199  */
200 void
201 vfs_timestamp(struct timespec *tsp)
202 {
203 	struct timeval tv;
204 
205 	switch (timestamp_precision) {
206 	case TSP_SEC:
207 		tsp->tv_sec = time_second;
208 		tsp->tv_nsec = 0;
209 		break;
210 	case TSP_HZ:
211 		getnanotime(tsp);
212 		break;
213 	case TSP_USEC:
214 		microtime(&tv);
215 		TIMEVAL_TO_TIMESPEC(&tv, tsp);
216 		break;
217 	case TSP_NSEC:
218 	default:
219 		nanotime(tsp);
220 		break;
221 	}
222 }
223 
224 /*
225  * Set vnode attributes to VNOVAL
226  */
227 void
228 vattr_null(struct vattr *vap)
229 {
230 	vap->va_type = VNON;
231 	vap->va_size = VNOVAL;
232 	vap->va_bytes = VNOVAL;
233 	vap->va_mode = VNOVAL;
234 	vap->va_nlink = VNOVAL;
235 	vap->va_uid = VNOVAL;
236 	vap->va_gid = VNOVAL;
237 	vap->va_fsid = VNOVAL;
238 	vap->va_fileid = VNOVAL;
239 	vap->va_blocksize = VNOVAL;
240 	vap->va_rmajor = VNOVAL;
241 	vap->va_rminor = VNOVAL;
242 	vap->va_atime.tv_sec = VNOVAL;
243 	vap->va_atime.tv_nsec = VNOVAL;
244 	vap->va_mtime.tv_sec = VNOVAL;
245 	vap->va_mtime.tv_nsec = VNOVAL;
246 	vap->va_ctime.tv_sec = VNOVAL;
247 	vap->va_ctime.tv_nsec = VNOVAL;
248 	vap->va_flags = VNOVAL;
249 	vap->va_gen = VNOVAL;
250 	vap->va_vaflags = 0;
251 	/* va_*_uuid fields are only valid if related flags are set */
252 }
253 
254 /*
255  * Flush out and invalidate all buffers associated with a vnode.
256  *
257  * vp must be locked.
258  */
259 static int vinvalbuf_bp(struct buf *bp, void *data);
260 
261 struct vinvalbuf_bp_info {
262 	struct vnode *vp;
263 	int slptimeo;
264 	int lkflags;
265 	int flags;
266 	int clean;
267 };
268 
269 int
270 vinvalbuf(struct vnode *vp, int flags, int slpflag, int slptimeo)
271 {
272 	struct vinvalbuf_bp_info info;
273 	vm_object_t object;
274 	int error;
275 
276 	lwkt_gettoken(&vp->v_token);
277 
278 	/*
279 	 * If we are being asked to save, call fsync to ensure that the inode
280 	 * is updated.
281 	 */
282 	if (flags & V_SAVE) {
283 		error = bio_track_wait(&vp->v_track_write, slpflag, slptimeo);
284 		if (error)
285 			goto done;
286 		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
287 			if ((error = VOP_FSYNC(vp, MNT_WAIT, 0)) != 0)
288 				goto done;
289 #if 0
290 			/*
291 			 * Dirty bufs may be left or generated via races
292 			 * in circumstances where vinvalbuf() is called on
293 			 * a vnode not undergoing reclamation.   Only
294 			 * panic if we are trying to reclaim the vnode.
295 			 */
296 			if ((vp->v_flag & VRECLAIMED) &&
297 			    (bio_track_active(&vp->v_track_write) ||
298 			    !RB_EMPTY(&vp->v_rbdirty_tree))) {
299 				panic("vinvalbuf: dirty bufs");
300 			}
301 #endif
302 		}
303   	}
304 	info.slptimeo = slptimeo;
305 	info.lkflags = LK_EXCLUSIVE | LK_SLEEPFAIL;
306 	if (slpflag & PCATCH)
307 		info.lkflags |= LK_PCATCH;
308 	info.flags = flags;
309 	info.vp = vp;
310 
311 	/*
312 	 * Flush the buffer cache until nothing is left, wait for all I/O
313 	 * to complete.  At least one pass is required.  We might block
314 	 * in the pip code so we have to re-check.  Order is important.
315 	 */
316 	do {
317 		/*
318 		 * Flush buffer cache
319 		 */
320 		if (!RB_EMPTY(&vp->v_rbclean_tree)) {
321 			info.clean = 1;
322 			error = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
323 					NULL, vinvalbuf_bp, &info);
324 		}
325 		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
326 			info.clean = 0;
327 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
328 					NULL, vinvalbuf_bp, &info);
329 		}
330 
331 		/*
332 		 * Wait for I/O completion.
333 		 */
334 		bio_track_wait(&vp->v_track_write, 0, 0);
335 		if ((object = vp->v_object) != NULL)
336 			refcount_wait(&object->paging_in_progress, "vnvlbx");
337 	} while (bio_track_active(&vp->v_track_write) ||
338 		 !RB_EMPTY(&vp->v_rbclean_tree) ||
339 		 !RB_EMPTY(&vp->v_rbdirty_tree));
340 
341 	/*
342 	 * Destroy the copy in the VM cache, too.
343 	 */
344 	if ((object = vp->v_object) != NULL) {
345 		vm_object_page_remove(object, 0, 0,
346 			(flags & V_SAVE) ? TRUE : FALSE);
347 	}
348 
349 	if (!RB_EMPTY(&vp->v_rbdirty_tree) || !RB_EMPTY(&vp->v_rbclean_tree))
350 		panic("vinvalbuf: flush failed");
351 	if (!RB_EMPTY(&vp->v_rbhash_tree))
352 		panic("vinvalbuf: flush failed, buffers still present");
353 	error = 0;
354 done:
355 	lwkt_reltoken(&vp->v_token);
356 	return (error);
357 }
358 
359 static int
360 vinvalbuf_bp(struct buf *bp, void *data)
361 {
362 	struct vinvalbuf_bp_info *info = data;
363 	int error;
364 
365 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
366 		atomic_add_int(&bp->b_refs, 1);
367 		error = BUF_TIMELOCK(bp, info->lkflags,
368 				     "vinvalbuf", info->slptimeo);
369 		atomic_subtract_int(&bp->b_refs, 1);
370 		if (error == 0) {
371 			BUF_UNLOCK(bp);
372 			error = ENOLCK;
373 		}
374 		if (error == ENOLCK)
375 			return(0);
376 		return (-error);
377 	}
378 	KKASSERT(bp->b_vp == info->vp);
379 
380 	/*
381 	 * Must check clean/dirty status after successfully locking as
382 	 * it may race.
383 	 */
384 	if ((info->clean && (bp->b_flags & B_DELWRI)) ||
385 	    (info->clean == 0 && (bp->b_flags & B_DELWRI) == 0)) {
386 		BUF_UNLOCK(bp);
387 		return(0);
388 	}
389 
390 	/*
391 	 * NOTE:  NO B_LOCKED CHECK.  Also no buf_checkwrite()
392 	 * check.  This code will write out the buffer, period.
393 	 */
394 	bremfree(bp);
395 	if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
396 	    (info->flags & V_SAVE)) {
397 		cluster_awrite(bp);
398 	} else if (info->flags & V_SAVE) {
399 		/*
400 		 * Cannot set B_NOCACHE on a clean buffer as this will
401 		 * destroy the VM backing store which might actually
402 		 * be dirty (and unsynchronized).
403 		 */
404 		bp->b_flags |= (B_INVAL | B_RELBUF);
405 		brelse(bp);
406 	} else {
407 		bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
408 		brelse(bp);
409 	}
410 	return(0);
411 }
412 
413 /*
414  * Truncate a file's buffer and pages to a specified length.  This
415  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
416  * sync activity.
417  *
418  * The vnode must be locked.
419  */
420 static int vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data);
421 static int vtruncbuf_bp_trunc(struct buf *bp, void *data);
422 static int vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data);
423 static int vtruncbuf_bp_metasync(struct buf *bp, void *data);
424 
425 struct vtruncbuf_info {
426 	struct vnode *vp;
427 	off_t	truncloffset;
428 	int	clean;
429 };
430 
431 int
432 vtruncbuf(struct vnode *vp, off_t length, int blksize)
433 {
434 	struct vtruncbuf_info info;
435 	const char *filename;
436 	int count;
437 
438 	/*
439 	 * Round up to the *next* block, then destroy the buffers in question.
440 	 * Since we are only removing some of the buffers we must rely on the
441 	 * scan count to determine whether a loop is necessary.
442 	 */
443 	if ((count = (int)(length % blksize)) != 0)
444 		info.truncloffset = length + (blksize - count);
445 	else
446 		info.truncloffset = length;
447 	info.vp = vp;
448 
449 	lwkt_gettoken(&vp->v_token);
450 	do {
451 		info.clean = 1;
452 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
453 				vtruncbuf_bp_trunc_cmp,
454 				vtruncbuf_bp_trunc, &info);
455 		info.clean = 0;
456 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
457 				vtruncbuf_bp_trunc_cmp,
458 				vtruncbuf_bp_trunc, &info);
459 	} while(count);
460 
461 	/*
462 	 * For safety, fsync any remaining metadata if the file is not being
463 	 * truncated to 0.  Since the metadata does not represent the entire
464 	 * dirty list we have to rely on the hit count to ensure that we get
465 	 * all of it.
466 	 */
467 	if (length > 0) {
468 		do {
469 			count = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
470 					vtruncbuf_bp_metasync_cmp,
471 					vtruncbuf_bp_metasync, &info);
472 		} while (count);
473 	}
474 
475 	/*
476 	 * Clean out any left over VM backing store.
477 	 *
478 	 * It is possible to have in-progress I/O from buffers that were
479 	 * not part of the truncation.  This should not happen if we
480 	 * are truncating to 0-length.
481 	 */
482 	vnode_pager_setsize(vp, length);
483 	bio_track_wait(&vp->v_track_write, 0, 0);
484 
485 	/*
486 	 * Debugging only
487 	 */
488 	spin_lock(&vp->v_spin);
489 	filename = TAILQ_FIRST(&vp->v_namecache) ?
490 		   TAILQ_FIRST(&vp->v_namecache)->nc_name : "?";
491 	spin_unlock(&vp->v_spin);
492 
493 	/*
494 	 * Make sure no buffers were instantiated while we were trying
495 	 * to clean out the remaining VM pages.  This could occur due
496 	 * to busy dirty VM pages being flushed out to disk.
497 	 */
498 	do {
499 		info.clean = 1;
500 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
501 				vtruncbuf_bp_trunc_cmp,
502 				vtruncbuf_bp_trunc, &info);
503 		info.clean = 0;
504 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
505 				vtruncbuf_bp_trunc_cmp,
506 				vtruncbuf_bp_trunc, &info);
507 		if (count) {
508 			kprintf("Warning: vtruncbuf():  Had to re-clean %d "
509 			       "left over buffers in %s\n", count, filename);
510 		}
511 	} while(count);
512 
513 	lwkt_reltoken(&vp->v_token);
514 
515 	return (0);
516 }
517 
518 /*
519  * The callback buffer is beyond the new file EOF and must be destroyed.
520  * Note that the compare function must conform to the RB_SCAN's requirements.
521  */
522 static
523 int
524 vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data)
525 {
526 	struct vtruncbuf_info *info = data;
527 
528 	if (bp->b_loffset >= info->truncloffset)
529 		return(0);
530 	return(-1);
531 }
532 
533 static
534 int
535 vtruncbuf_bp_trunc(struct buf *bp, void *data)
536 {
537 	struct vtruncbuf_info *info = data;
538 
539 	/*
540 	 * Do not try to use a buffer we cannot immediately lock, but sleep
541 	 * anyway to prevent a livelock.  The code will loop until all buffers
542 	 * can be acted upon.
543 	 *
544 	 * We must always revalidate the buffer after locking it to deal
545 	 * with MP races.
546 	 */
547 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
548 		atomic_add_int(&bp->b_refs, 1);
549 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
550 			BUF_UNLOCK(bp);
551 		atomic_subtract_int(&bp->b_refs, 1);
552 	} else if ((info->clean && (bp->b_flags & B_DELWRI)) ||
553 		   (info->clean == 0 && (bp->b_flags & B_DELWRI) == 0) ||
554 		   bp->b_vp != info->vp ||
555 		   vtruncbuf_bp_trunc_cmp(bp, data)) {
556 		BUF_UNLOCK(bp);
557 	} else {
558 		bremfree(bp);
559 		bp->b_flags |= (B_INVAL | B_RELBUF | B_NOCACHE);
560 		brelse(bp);
561 	}
562 	return(1);
563 }
564 
565 /*
566  * Fsync all meta-data after truncating a file to be non-zero.  Only metadata
567  * blocks (with a negative loffset) are scanned.
568  * Note that the compare function must conform to the RB_SCAN's requirements.
569  */
570 static int
571 vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data __unused)
572 {
573 	if (bp->b_loffset < 0)
574 		return(0);
575 	return(1);
576 }
577 
578 static int
579 vtruncbuf_bp_metasync(struct buf *bp, void *data)
580 {
581 	struct vtruncbuf_info *info = data;
582 
583 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
584 		atomic_add_int(&bp->b_refs, 1);
585 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
586 			BUF_UNLOCK(bp);
587 		atomic_subtract_int(&bp->b_refs, 1);
588 	} else if ((bp->b_flags & B_DELWRI) == 0 ||
589 		   bp->b_vp != info->vp ||
590 		   vtruncbuf_bp_metasync_cmp(bp, data)) {
591 		BUF_UNLOCK(bp);
592 	} else {
593 		bremfree(bp);
594 		if (bp->b_vp == info->vp)
595 			bawrite(bp);
596 		else
597 			bwrite(bp);
598 	}
599 	return(1);
600 }
601 
602 /*
603  * vfsync - implements a multipass fsync on a file which understands
604  * dependancies and meta-data.  The passed vnode must be locked.  The
605  * waitfor argument may be MNT_WAIT or MNT_NOWAIT, or MNT_LAZY.
606  *
607  * When fsyncing data asynchronously just do one consolidated pass starting
608  * with the most negative block number.  This may not get all the data due
609  * to dependancies.
610  *
611  * When fsyncing data synchronously do a data pass, then a metadata pass,
612  * then do additional data+metadata passes to try to get all the data out.
613  *
614  * Caller must ref the vnode but does not have to lock it.
615  */
616 static int vfsync_wait_output(struct vnode *vp,
617 			    int (*waitoutput)(struct vnode *, struct thread *));
618 static int vfsync_dummy_cmp(struct buf *bp __unused, void *data __unused);
619 static int vfsync_data_only_cmp(struct buf *bp, void *data);
620 static int vfsync_meta_only_cmp(struct buf *bp, void *data);
621 static int vfsync_lazy_range_cmp(struct buf *bp, void *data);
622 static int vfsync_bp(struct buf *bp, void *data);
623 
624 struct vfsync_info {
625 	struct vnode *vp;
626 	int fastpass;
627 	int synchronous;
628 	int syncdeps;
629 	int lazycount;
630 	int lazylimit;
631 	int skippedbufs;
632 	int (*checkdef)(struct buf *);
633 	int (*cmpfunc)(struct buf *, void *);
634 };
635 
636 int
637 vfsync(struct vnode *vp, int waitfor, int passes,
638 	int (*checkdef)(struct buf *),
639 	int (*waitoutput)(struct vnode *, struct thread *))
640 {
641 	struct vfsync_info info;
642 	int error;
643 
644 	bzero(&info, sizeof(info));
645 	info.vp = vp;
646 	if ((info.checkdef = checkdef) == NULL)
647 		info.syncdeps = 1;
648 
649 	lwkt_gettoken(&vp->v_token);
650 
651 	switch(waitfor) {
652 	case MNT_LAZY | MNT_NOWAIT:
653 	case MNT_LAZY:
654 		/*
655 		 * Lazy (filesystem syncer typ) Asynchronous plus limit the
656 		 * number of data (not meta) pages we try to flush to 1MB.
657 		 * A non-zero return means that lazy limit was reached.
658 		 */
659 		info.lazylimit = 1024 * 1024;
660 		info.syncdeps = 1;
661 		info.cmpfunc = vfsync_lazy_range_cmp;
662 		error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
663 				vfsync_lazy_range_cmp, vfsync_bp, &info);
664 		info.cmpfunc = vfsync_meta_only_cmp;
665 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
666 			vfsync_meta_only_cmp, vfsync_bp, &info);
667 		if (error == 0)
668 			vp->v_lazyw = 0;
669 		else if (!RB_EMPTY(&vp->v_rbdirty_tree))
670 			vn_syncer_add(vp, 1);
671 		error = 0;
672 		break;
673 	case MNT_NOWAIT:
674 		/*
675 		 * Asynchronous.  Do a data-only pass and a meta-only pass.
676 		 */
677 		info.syncdeps = 1;
678 		info.cmpfunc = vfsync_data_only_cmp;
679 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
680 			vfsync_bp, &info);
681 		info.cmpfunc = vfsync_meta_only_cmp;
682 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_meta_only_cmp,
683 			vfsync_bp, &info);
684 		error = 0;
685 		break;
686 	default:
687 		/*
688 		 * Synchronous.  Do a data-only pass, then a meta-data+data
689 		 * pass, then additional integrated passes to try to get
690 		 * all the dependancies flushed.
691 		 */
692 		info.cmpfunc = vfsync_data_only_cmp;
693 		info.fastpass = 1;
694 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
695 			vfsync_bp, &info);
696 		info.fastpass = 0;
697 		error = vfsync_wait_output(vp, waitoutput);
698 		if (error == 0) {
699 			info.skippedbufs = 0;
700 			info.cmpfunc = vfsync_dummy_cmp;
701 			RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
702 				vfsync_bp, &info);
703 			error = vfsync_wait_output(vp, waitoutput);
704 			if (info.skippedbufs) {
705 				kprintf("Warning: vfsync skipped %d dirty "
706 					"buf%s in pass2!\n",
707 					info.skippedbufs,
708 					((info.skippedbufs > 1) ? "s" : ""));
709 			}
710 		}
711 		while (error == 0 && passes > 0 &&
712 		       !RB_EMPTY(&vp->v_rbdirty_tree)
713 		) {
714 			info.skippedbufs = 0;
715 			if (--passes == 0) {
716 				info.synchronous = 1;
717 				info.syncdeps = 1;
718 			}
719 			info.cmpfunc = vfsync_dummy_cmp;
720 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
721 					vfsync_bp, &info);
722 			if (error < 0)
723 				error = -error;
724 			info.syncdeps = 1;
725 			if (error == 0)
726 				error = vfsync_wait_output(vp, waitoutput);
727 			if (info.skippedbufs && passes == 0) {
728 				kprintf("Warning: vfsync skipped %d dirty "
729 					"buf%s in final pass!\n",
730 					info.skippedbufs,
731 					((info.skippedbufs > 1) ? "s" : ""));
732 			}
733 		}
734 #if 0
735 		/*
736 		 * This case can occur normally because vnode lock might
737 		 * not be held.
738 		 */
739 		if (!RB_EMPTY(&vp->v_rbdirty_tree))
740 			kprintf("dirty bufs left after final pass\n");
741 #endif
742 		break;
743 	}
744 	lwkt_reltoken(&vp->v_token);
745 
746 	return(error);
747 }
748 
749 static int
750 vfsync_wait_output(struct vnode *vp,
751 		   int (*waitoutput)(struct vnode *, struct thread *))
752 {
753 	int error;
754 
755 	error = bio_track_wait(&vp->v_track_write, 0, 0);
756 	if (waitoutput)
757 		error = waitoutput(vp, curthread);
758 	return(error);
759 }
760 
761 static int
762 vfsync_dummy_cmp(struct buf *bp __unused, void *data __unused)
763 {
764 	return(0);
765 }
766 
767 static int
768 vfsync_data_only_cmp(struct buf *bp, void *data)
769 {
770 	if (bp->b_loffset < 0)
771 		return(-1);
772 	return(0);
773 }
774 
775 static int
776 vfsync_meta_only_cmp(struct buf *bp, void *data)
777 {
778 	if (bp->b_loffset < 0)
779 		return(0);
780 	return(1);
781 }
782 
783 static int
784 vfsync_lazy_range_cmp(struct buf *bp, void *data)
785 {
786 	struct vfsync_info *info = data;
787 
788 	if (bp->b_loffset < info->vp->v_lazyw)
789 		return(-1);
790 	return(0);
791 }
792 
793 static int
794 vfsync_bp(struct buf *bp, void *data)
795 {
796 	struct vfsync_info *info = data;
797 	struct vnode *vp = info->vp;
798 	int error;
799 
800 	if (info->fastpass) {
801 		/*
802 		 * Ignore buffers that we cannot immediately lock.
803 		 */
804 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
805 			if (BUF_TIMELOCK(bp, LK_EXCLUSIVE, "bflst1", 1)) {
806 				++info->skippedbufs;
807 				return(0);
808 			}
809 		}
810 	} else if (info->synchronous == 0) {
811 		/*
812 		 * Normal pass, give the buffer a little time to become
813 		 * available to us.
814 		 */
815 		if (BUF_TIMELOCK(bp, LK_EXCLUSIVE, "bflst2", hz / 10)) {
816 			++info->skippedbufs;
817 			return(0);
818 		}
819 	} else {
820 		/*
821 		 * Synchronous pass, give the buffer a lot of time before
822 		 * giving up.
823 		 */
824 		if (BUF_TIMELOCK(bp, LK_EXCLUSIVE, "bflst3", hz * 10)) {
825 			++info->skippedbufs;
826 			return(0);
827 		}
828 	}
829 
830 	/*
831 	 * We must revalidate the buffer after locking.
832 	 */
833 	if ((bp->b_flags & B_DELWRI) == 0 ||
834 	    bp->b_vp != info->vp ||
835 	    info->cmpfunc(bp, data)) {
836 		BUF_UNLOCK(bp);
837 		return(0);
838 	}
839 
840 	/*
841 	 * If syncdeps is not set we do not try to write buffers which have
842 	 * dependancies.
843 	 */
844 	if (!info->synchronous && info->syncdeps == 0 && info->checkdef(bp)) {
845 		BUF_UNLOCK(bp);
846 		return(0);
847 	}
848 
849 	/*
850 	 * B_NEEDCOMMIT (primarily used by NFS) is a state where the buffer
851 	 * has been written but an additional handshake with the device
852 	 * is required before we can dispose of the buffer.  We have no idea
853 	 * how to do this so we have to skip these buffers.
854 	 */
855 	if (bp->b_flags & B_NEEDCOMMIT) {
856 		BUF_UNLOCK(bp);
857 		return(0);
858 	}
859 
860 	/*
861 	 * Ask bioops if it is ok to sync.  If not the VFS may have
862 	 * set B_LOCKED so we have to cycle the buffer.
863 	 */
864 	if (LIST_FIRST(&bp->b_dep) != NULL && buf_checkwrite(bp)) {
865 		bremfree(bp);
866 		brelse(bp);
867 		return(0);
868 	}
869 
870 	if (info->synchronous) {
871 		/*
872 		 * Synchronous flushing.  An error may be returned.
873 		 */
874 		bremfree(bp);
875 		error = bwrite(bp);
876 	} else {
877 		/*
878 		 * Asynchronous flushing.  A negative return value simply
879 		 * stops the scan and is not considered an error.  We use
880 		 * this to support limited MNT_LAZY flushes.
881 		 */
882 		vp->v_lazyw = bp->b_loffset;
883 		bremfree(bp);
884 		info->lazycount += cluster_awrite(bp);
885 		waitrunningbufspace();
886 		vm_wait_nominal();
887 		if (info->lazylimit && info->lazycount >= info->lazylimit)
888 			error = 1;
889 		else
890 			error = 0;
891 	}
892 	return(-error);
893 }
894 
895 /*
896  * Associate a buffer with a vnode.
897  *
898  * MPSAFE
899  */
900 int
901 bgetvp(struct vnode *vp, struct buf *bp, int testsize)
902 {
903 	KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));
904 	KKASSERT((bp->b_flags & (B_HASHED|B_DELWRI|B_VNCLEAN|B_VNDIRTY)) == 0);
905 
906 	/*
907 	 * Insert onto list for new vnode.
908 	 */
909 	lwkt_gettoken(&vp->v_token);
910 
911 	if (buf_rb_hash_RB_INSERT(&vp->v_rbhash_tree, bp)) {
912 		lwkt_reltoken(&vp->v_token);
913 		return (EEXIST);
914 	}
915 
916 	/*
917 	 * Diagnostics (mainly for HAMMER debugging).  Check for
918 	 * overlapping buffers.
919 	 */
920 	if (check_buf_overlap) {
921 		struct buf *bx;
922 		bx = buf_rb_hash_RB_PREV(bp);
923 		if (bx) {
924 			if (bx->b_loffset + bx->b_bufsize > bp->b_loffset) {
925 				kprintf("bgetvp: overlapl %016jx/%d %016jx "
926 					"bx %p bp %p\n",
927 					(intmax_t)bx->b_loffset,
928 					bx->b_bufsize,
929 					(intmax_t)bp->b_loffset,
930 					bx, bp);
931 				if (check_buf_overlap > 1)
932 					panic("bgetvp - overlapping buffer");
933 			}
934 		}
935 		bx = buf_rb_hash_RB_NEXT(bp);
936 		if (bx) {
937 			if (bp->b_loffset + testsize > bx->b_loffset) {
938 				kprintf("bgetvp: overlapr %016jx/%d %016jx "
939 					"bp %p bx %p\n",
940 					(intmax_t)bp->b_loffset,
941 					testsize,
942 					(intmax_t)bx->b_loffset,
943 					bp, bx);
944 				if (check_buf_overlap > 1)
945 					panic("bgetvp - overlapping buffer");
946 			}
947 		}
948 	}
949 	bp->b_vp = vp;
950 	bp->b_flags |= B_HASHED;
951 	bp->b_flags |= B_VNCLEAN;
952 	if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp))
953 		panic("reassignbuf: dup lblk/clean vp %p bp %p", vp, bp);
954 	/*vhold(vp);*/
955 	lwkt_reltoken(&vp->v_token);
956 	return(0);
957 }
958 
959 /*
960  * Disassociate a buffer from a vnode.
961  *
962  * MPSAFE
963  */
964 void
965 brelvp(struct buf *bp)
966 {
967 	struct vnode *vp;
968 
969 	KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
970 
971 	/*
972 	 * Delete from old vnode list, if on one.
973 	 */
974 	vp = bp->b_vp;
975 	lwkt_gettoken(&vp->v_token);
976 	if (bp->b_flags & (B_VNDIRTY | B_VNCLEAN)) {
977 		if (bp->b_flags & B_VNDIRTY)
978 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
979 		else
980 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
981 		bp->b_flags &= ~(B_VNDIRTY | B_VNCLEAN);
982 	}
983 	if (bp->b_flags & B_HASHED) {
984 		buf_rb_hash_RB_REMOVE(&vp->v_rbhash_tree, bp);
985 		bp->b_flags &= ~B_HASHED;
986 	}
987 
988 	/*
989 	 * Only remove from synclist when no dirty buffers are left AND
990 	 * the VFS has not flagged the vnode's inode as being dirty.
991 	 */
992 	if ((vp->v_flag & (VONWORKLST | VISDIRTY | VOBJDIRTY)) == VONWORKLST &&
993 	    RB_EMPTY(&vp->v_rbdirty_tree)) {
994 		vn_syncer_remove(vp, 0);
995 	}
996 	bp->b_vp = NULL;
997 
998 	lwkt_reltoken(&vp->v_token);
999 
1000 	/*vdrop(vp);*/
1001 }
1002 
1003 /*
1004  * Reassign the buffer to the proper clean/dirty list based on B_DELWRI.
1005  * This routine is called when the state of the B_DELWRI bit is changed.
1006  *
1007  * Must be called with vp->v_token held.
1008  * MPSAFE
1009  */
1010 void
1011 reassignbuf(struct buf *bp)
1012 {
1013 	struct vnode *vp = bp->b_vp;
1014 	int delay;
1015 
1016 	ASSERT_LWKT_TOKEN_HELD(&vp->v_token);
1017 	++reassignbufcalls;
1018 
1019 	/*
1020 	 * B_PAGING flagged buffers cannot be reassigned because their vp
1021 	 * is not fully linked in.
1022 	 */
1023 	if (bp->b_flags & B_PAGING)
1024 		panic("cannot reassign paging buffer");
1025 
1026 	if (bp->b_flags & B_DELWRI) {
1027 		/*
1028 		 * Move to the dirty list, add the vnode to the worklist
1029 		 */
1030 		if (bp->b_flags & B_VNCLEAN) {
1031 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
1032 			bp->b_flags &= ~B_VNCLEAN;
1033 		}
1034 		if ((bp->b_flags & B_VNDIRTY) == 0) {
1035 			if (buf_rb_tree_RB_INSERT(&vp->v_rbdirty_tree, bp)) {
1036 				panic("reassignbuf: dup lblk vp %p bp %p",
1037 				      vp, bp);
1038 			}
1039 			bp->b_flags |= B_VNDIRTY;
1040 		}
1041 		if ((vp->v_flag & VONWORKLST) == 0) {
1042 			switch (vp->v_type) {
1043 			case VDIR:
1044 				delay = dirdelay;
1045 				break;
1046 			case VCHR:
1047 			case VBLK:
1048 				if (vp->v_rdev &&
1049 				    vp->v_rdev->si_mountpoint != NULL) {
1050 					delay = metadelay;
1051 					break;
1052 				}
1053 				/* fall through */
1054 			default:
1055 				delay = filedelay;
1056 			}
1057 			vn_syncer_add(vp, delay);
1058 		}
1059 	} else {
1060 		/*
1061 		 * Move to the clean list, remove the vnode from the worklist
1062 		 * if no dirty blocks remain.
1063 		 */
1064 		if (bp->b_flags & B_VNDIRTY) {
1065 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
1066 			bp->b_flags &= ~B_VNDIRTY;
1067 		}
1068 		if ((bp->b_flags & B_VNCLEAN) == 0) {
1069 			if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp)) {
1070 				panic("reassignbuf: dup lblk vp %p bp %p",
1071 				      vp, bp);
1072 			}
1073 			bp->b_flags |= B_VNCLEAN;
1074 		}
1075 
1076 		/*
1077 		 * Only remove from synclist when no dirty buffers are left
1078 		 * AND the VFS has not flagged the vnode's inode as being
1079 		 * dirty.
1080 		 */
1081 		if ((vp->v_flag & (VONWORKLST | VISDIRTY | VOBJDIRTY)) ==
1082 		     VONWORKLST &&
1083 		    RB_EMPTY(&vp->v_rbdirty_tree)) {
1084 			vn_syncer_remove(vp, 0);
1085 		}
1086 	}
1087 }
1088 
1089 /*
1090  * Create a vnode for a block device.  Used for mounting the root file
1091  * system.
1092  *
1093  * A vref()'d vnode is returned.
1094  */
1095 extern struct vop_ops *devfs_vnode_dev_vops_p;
1096 int
1097 bdevvp(cdev_t dev, struct vnode **vpp)
1098 {
1099 	struct vnode *vp;
1100 	struct vnode *nvp;
1101 	int error;
1102 
1103 	if (dev == NULL) {
1104 		*vpp = NULLVP;
1105 		return (ENXIO);
1106 	}
1107 	error = getspecialvnode(VT_NON, NULL, &devfs_vnode_dev_vops_p,
1108 				&nvp, 0, 0);
1109 	if (error) {
1110 		*vpp = NULLVP;
1111 		return (error);
1112 	}
1113 	vp = nvp;
1114 	vp->v_type = VCHR;
1115 #if 0
1116 	vp->v_rdev = dev;
1117 #endif
1118 	v_associate_rdev(vp, dev);
1119 	vp->v_umajor = dev->si_umajor;
1120 	vp->v_uminor = dev->si_uminor;
1121 	vx_unlock(vp);
1122 	*vpp = vp;
1123 	return (0);
1124 }
1125 
1126 int
1127 v_associate_rdev(struct vnode *vp, cdev_t dev)
1128 {
1129 	if (dev == NULL)
1130 		return(ENXIO);
1131 	if (dev_is_good(dev) == 0)
1132 		return(ENXIO);
1133 	KKASSERT(vp->v_rdev == NULL);
1134 	vp->v_rdev = reference_dev(dev);
1135 	lwkt_gettoken(&spechash_token);
1136 	SLIST_INSERT_HEAD(&dev->si_hlist, vp, v_cdevnext);
1137 	lwkt_reltoken(&spechash_token);
1138 	return(0);
1139 }
1140 
1141 void
1142 v_release_rdev(struct vnode *vp)
1143 {
1144 	cdev_t dev;
1145 
1146 	if ((dev = vp->v_rdev) != NULL) {
1147 		lwkt_gettoken(&spechash_token);
1148 		SLIST_REMOVE(&dev->si_hlist, vp, vnode, v_cdevnext);
1149 		vp->v_rdev = NULL;
1150 		release_dev(dev);
1151 		lwkt_reltoken(&spechash_token);
1152 	}
1153 }
1154 
1155 /*
1156  * Add a vnode to the alias list hung off the cdev_t.  We only associate
1157  * the device number with the vnode.  The actual device is not associated
1158  * until the vnode is opened (usually in spec_open()), and will be
1159  * disassociated on last close.
1160  */
1161 void
1162 addaliasu(struct vnode *nvp, int x, int y)
1163 {
1164 	if (nvp->v_type != VBLK && nvp->v_type != VCHR)
1165 		panic("addaliasu on non-special vnode");
1166 	nvp->v_umajor = x;
1167 	nvp->v_uminor = y;
1168 }
1169 
1170 /*
1171  * Simple call that a filesystem can make to try to get rid of a
1172  * vnode.  It will fail if anyone is referencing the vnode (including
1173  * the caller).
1174  *
1175  * The filesystem can check whether its in-memory inode structure still
1176  * references the vp on return.
1177  *
1178  * May only be called if the vnode is in a known state (i.e. being prevented
1179  * from being deallocated by some other condition such as a vfs inode hold).
1180  */
1181 void
1182 vclean_unlocked(struct vnode *vp)
1183 {
1184 	vx_get(vp);
1185 	if (VREFCNT(vp) <= 1)
1186 		vgone_vxlocked(vp);
1187 	vx_put(vp);
1188 }
1189 
1190 /*
1191  * Disassociate a vnode from its underlying filesystem.
1192  *
1193  * The vnode must be VX locked and referenced.  In all normal situations
1194  * there are no active references.  If vclean_vxlocked() is called while
1195  * there are active references, the vnode is being ripped out and we have
1196  * to call VOP_CLOSE() as appropriate before we can reclaim it.
1197  */
1198 void
1199 vclean_vxlocked(struct vnode *vp, int flags)
1200 {
1201 	int active;
1202 	int n;
1203 	vm_object_t object;
1204 	struct namecache *ncp;
1205 
1206 	/*
1207 	 * If the vnode has already been reclaimed we have nothing to do.
1208 	 */
1209 	if (vp->v_flag & VRECLAIMED)
1210 		return;
1211 
1212 	/*
1213 	 * Set flag to interlock operation, flag finalization to ensure
1214 	 * that the vnode winds up on the inactive list, and set v_act to 0.
1215 	 */
1216 	vsetflags(vp, VRECLAIMED);
1217 	atomic_set_int(&vp->v_refcnt, VREF_FINALIZE);
1218 	vp->v_act = 0;
1219 
1220 	if (verbose_reclaims) {
1221 		if ((ncp = TAILQ_FIRST(&vp->v_namecache)) != NULL)
1222 			kprintf("Debug: reclaim %p %s\n", vp, ncp->nc_name);
1223 	}
1224 
1225 	/*
1226 	 * Scrap the vfs cache
1227 	 */
1228 	while (cache_inval_vp(vp, 0) != 0) {
1229 		kprintf("Warning: vnode %p clean/cache_resolution "
1230 			"race detected\n", vp);
1231 		tsleep(vp, 0, "vclninv", 2);
1232 	}
1233 
1234 	/*
1235 	 * Check to see if the vnode is in use. If so we have to reference it
1236 	 * before we clean it out so that its count cannot fall to zero and
1237 	 * generate a race against ourselves to recycle it.
1238 	 */
1239 	active = (VREFCNT(vp) > 0);
1240 
1241 	/*
1242 	 * Clean out any buffers associated with the vnode and destroy its
1243 	 * object, if it has one.
1244 	 */
1245 	vinvalbuf(vp, V_SAVE, 0, 0);
1246 	KKASSERT(lockcountnb(&vp->v_lock) == 1);
1247 
1248 	/*
1249 	 * If purging an active vnode (typically during a forced unmount
1250 	 * or reboot), it must be closed and deactivated before being
1251 	 * reclaimed.  This isn't really all that safe, but what can
1252 	 * we do? XXX.
1253 	 *
1254 	 * Note that neither of these routines unlocks the vnode.
1255 	 */
1256 	if (active && (flags & DOCLOSE)) {
1257 		while ((n = vp->v_opencount) != 0) {
1258 			if (vp->v_writecount)
1259 				VOP_CLOSE(vp, FWRITE|FNONBLOCK, NULL);
1260 			else
1261 				VOP_CLOSE(vp, FNONBLOCK, NULL);
1262 			if (vp->v_opencount == n) {
1263 				kprintf("Warning: unable to force-close"
1264 				       " vnode %p\n", vp);
1265 				break;
1266 			}
1267 		}
1268 	}
1269 
1270 	/*
1271 	 * If the vnode has not been deactivated, deactivated it.  Deactivation
1272 	 * can create new buffers and VM pages so we have to call vinvalbuf()
1273 	 * again to make sure they all get flushed.
1274 	 *
1275 	 * This can occur if a file with a link count of 0 needs to be
1276 	 * truncated.
1277 	 *
1278 	 * If the vnode is already dead don't try to deactivate it.
1279 	 */
1280 	if ((vp->v_flag & VINACTIVE) == 0) {
1281 		vsetflags(vp, VINACTIVE);
1282 		if (vp->v_mount)
1283 			VOP_INACTIVE(vp);
1284 		vinvalbuf(vp, V_SAVE, 0, 0);
1285 	}
1286 	KKASSERT(lockcountnb(&vp->v_lock) == 1);
1287 
1288 	/*
1289 	 * If the vnode has an object, destroy it.
1290 	 */
1291 	while ((object = vp->v_object) != NULL) {
1292 		vm_object_hold(object);
1293 		if (object == vp->v_object)
1294 			break;
1295 		vm_object_drop(object);
1296 	}
1297 
1298 	if (object != NULL) {
1299 		if (object->ref_count == 0) {
1300 			if ((object->flags & OBJ_DEAD) == 0)
1301 				vm_object_terminate(object);
1302 			vm_object_drop(object);
1303 			vclrflags(vp, VOBJBUF);
1304 		} else {
1305 			vm_pager_deallocate(object);
1306 			vclrflags(vp, VOBJBUF);
1307 			vm_object_drop(object);
1308 		}
1309 	}
1310 	KKASSERT((vp->v_flag & VOBJBUF) == 0);
1311 
1312 	/*
1313 	 * Reclaim the vnode if not already dead.
1314 	 */
1315 	if (vp->v_mount && VOP_RECLAIM(vp))
1316 		panic("vclean: cannot reclaim");
1317 
1318 	/*
1319 	 * Done with purge, notify sleepers of the grim news.
1320 	 */
1321 	vp->v_ops = &dead_vnode_vops_p;
1322 	vn_gone(vp);
1323 	vp->v_tag = VT_NON;
1324 
1325 	/*
1326 	 * If we are destroying an active vnode, reactivate it now that
1327 	 * we have reassociated it with deadfs.  This prevents the system
1328 	 * from crashing on the vnode due to it being unexpectedly marked
1329 	 * as inactive or reclaimed.
1330 	 */
1331 	if (active && (flags & DOCLOSE)) {
1332 		vclrflags(vp, VINACTIVE | VRECLAIMED);
1333 	}
1334 }
1335 
1336 /*
1337  * Eliminate all activity associated with the requested vnode
1338  * and with all vnodes aliased to the requested vnode.
1339  *
1340  * The vnode must be referenced but should not be locked.
1341  */
1342 int
1343 vrevoke(struct vnode *vp, struct ucred *cred)
1344 {
1345 	struct vnode *vq;
1346 	struct vnode *vqn;
1347 	cdev_t dev;
1348 	int error;
1349 
1350 	/*
1351 	 * If the vnode has a device association, scrap all vnodes associated
1352 	 * with the device.  Don't let the device disappear on us while we
1353 	 * are scrapping the vnodes.
1354 	 *
1355 	 * The passed vp will probably show up in the list, do not VX lock
1356 	 * it twice!
1357 	 *
1358 	 * Releasing the vnode's rdev here can mess up specfs's call to
1359 	 * device close, so don't do it.  The vnode has been disassociated
1360 	 * and the device will be closed after the last ref on the related
1361 	 * fp goes away (if not still open by e.g. the kernel).
1362 	 */
1363 	if (vp->v_type != VCHR) {
1364 		error = fdrevoke(vp, DTYPE_VNODE, cred);
1365 		return (error);
1366 	}
1367 	if ((dev = vp->v_rdev) == NULL) {
1368 		return(0);
1369 	}
1370 	reference_dev(dev);
1371 	lwkt_gettoken(&spechash_token);
1372 
1373 restart:
1374 	vqn = SLIST_FIRST(&dev->si_hlist);
1375 	if (vqn)
1376 		vhold(vqn);
1377 	while ((vq = vqn) != NULL) {
1378 		if (VREFCNT(vq) > 0) {
1379 			vref(vq);
1380 			fdrevoke(vq, DTYPE_VNODE, cred);
1381 			/*v_release_rdev(vq);*/
1382 			vrele(vq);
1383 			if (vq->v_rdev != dev) {
1384 				vdrop(vq);
1385 				goto restart;
1386 			}
1387 		}
1388 		vqn = SLIST_NEXT(vq, v_cdevnext);
1389 		if (vqn)
1390 			vhold(vqn);
1391 		vdrop(vq);
1392 	}
1393 	lwkt_reltoken(&spechash_token);
1394 	dev_drevoke(dev);
1395 	release_dev(dev);
1396 	return (0);
1397 }
1398 
1399 /*
1400  * This is called when the object underlying a vnode is being destroyed,
1401  * such as in a remove().  Try to recycle the vnode immediately if the
1402  * only active reference is our reference.
1403  *
1404  * Directory vnodes in the namecache with children cannot be immediately
1405  * recycled because numerous VOP_N*() ops require them to be stable.
1406  *
1407  * To avoid recursive recycling from VOP_INACTIVE implemenetations this
1408  * function is a NOP if VRECLAIMED is already set.
1409  */
1410 int
1411 vrecycle(struct vnode *vp)
1412 {
1413 	if (VREFCNT(vp) <= 1 && (vp->v_flag & VRECLAIMED) == 0) {
1414 		if (cache_inval_vp_nonblock(vp))
1415 			return(0);
1416 		vgone_vxlocked(vp);
1417 		return (1);
1418 	}
1419 	return (0);
1420 }
1421 
1422 /*
1423  * Return the maximum I/O size allowed for strategy calls on VP.
1424  *
1425  * If vp is VCHR or VBLK we dive the device, otherwise we use
1426  * the vp's mount info.
1427  *
1428  * The returned value is clamped at MAXPHYS as most callers cannot use
1429  * buffers larger than that size.
1430  */
1431 int
1432 vmaxiosize(struct vnode *vp)
1433 {
1434 	int maxiosize;
1435 
1436 	if (vp->v_type == VBLK || vp->v_type == VCHR)
1437 		maxiosize = vp->v_rdev->si_iosize_max;
1438 	else
1439 		maxiosize = vp->v_mount->mnt_iosize_max;
1440 
1441 	if (maxiosize > MAXPHYS)
1442 		maxiosize = MAXPHYS;
1443 	return (maxiosize);
1444 }
1445 
1446 /*
1447  * Eliminate all activity associated with a vnode in preparation for
1448  * destruction.
1449  *
1450  * The vnode must be VX locked and refd and will remain VX locked and refd
1451  * on return.  This routine may be called with the vnode in any state, as
1452  * long as it is VX locked.  The vnode will be cleaned out and marked
1453  * VRECLAIMED but will not actually be reused until all existing refs and
1454  * holds go away.
1455  *
1456  * NOTE: This routine may be called on a vnode which has not yet been
1457  * already been deactivated (VOP_INACTIVE), or on a vnode which has
1458  * already been reclaimed.
1459  *
1460  * This routine is not responsible for placing us back on the freelist.
1461  * Instead, it happens automatically when the caller releases the VX lock
1462  * (assuming there aren't any other references).
1463  */
1464 void
1465 vgone_vxlocked(struct vnode *vp)
1466 {
1467 	/*
1468 	 * assert that the VX lock is held.  This is an absolute requirement
1469 	 * now for vgone_vxlocked() to be called.
1470 	 */
1471 	KKASSERT(lockcountnb(&vp->v_lock) == 1);
1472 
1473 	/*
1474 	 * Clean out the filesystem specific data and set the VRECLAIMED
1475 	 * bit.  Also deactivate the vnode if necessary.
1476 	 *
1477 	 * The vnode should have automatically been removed from the syncer
1478 	 * list as syncer/dirty flags cleared during the cleaning.
1479 	 */
1480 	vclean_vxlocked(vp, DOCLOSE);
1481 
1482 	/*
1483 	 * Normally panic if the vnode is still dirty, unless we are doing
1484 	 * a forced unmount (tmpfs typically).
1485 	 */
1486 	if (vp->v_flag & VONWORKLST) {
1487 		if (vp->v_mount->mnt_kern_flag & MNTK_UNMOUNTF) {
1488 			/* force removal */
1489 			vn_syncer_remove(vp, 1);
1490 		} else {
1491 			panic("vp %p still dirty in vgone after flush", vp);
1492 		}
1493 	}
1494 
1495 	/*
1496 	 * Delete from old mount point vnode list, if on one.
1497 	 */
1498 	if (vp->v_mount != NULL) {
1499 		KKASSERT(vp->v_data == NULL);
1500 		insmntque(vp, NULL);
1501 	}
1502 
1503 	/*
1504 	 * If special device, remove it from special device alias list
1505 	 * if it is on one.  This should normally only occur if a vnode is
1506 	 * being revoked as the device should otherwise have been released
1507 	 * naturally.
1508 	 */
1509 	if ((vp->v_type == VBLK || vp->v_type == VCHR) && vp->v_rdev != NULL) {
1510 		v_release_rdev(vp);
1511 	}
1512 
1513 	/*
1514 	 * Set us to VBAD
1515 	 */
1516 	vp->v_type = VBAD;
1517 }
1518 
1519 /*
1520  * Lookup a vnode by device number.
1521  *
1522  * Returns non-zero and *vpp set to a vref'd vnode on success.
1523  * Returns zero on failure.
1524  */
1525 int
1526 vfinddev(cdev_t dev, enum vtype type, struct vnode **vpp)
1527 {
1528 	struct vnode *vp;
1529 
1530 	lwkt_gettoken(&spechash_token);
1531 	SLIST_FOREACH(vp, &dev->si_hlist, v_cdevnext) {
1532 		if (type == vp->v_type) {
1533 			*vpp = vp;
1534 			vref(vp);
1535 			lwkt_reltoken(&spechash_token);
1536 			return (1);
1537 		}
1538 	}
1539 	lwkt_reltoken(&spechash_token);
1540 	return (0);
1541 }
1542 
1543 /*
1544  * Calculate the total number of references to a special device.  This
1545  * routine may only be called for VBLK and VCHR vnodes since v_rdev is
1546  * an overloaded field.  Since udev2dev can now return NULL, we have
1547  * to check for a NULL v_rdev.
1548  */
1549 int
1550 count_dev(cdev_t dev)
1551 {
1552 	struct vnode *vp;
1553 	int count = 0;
1554 
1555 	if (SLIST_FIRST(&dev->si_hlist)) {
1556 		lwkt_gettoken(&spechash_token);
1557 		SLIST_FOREACH(vp, &dev->si_hlist, v_cdevnext) {
1558 			count += vp->v_opencount;
1559 		}
1560 		lwkt_reltoken(&spechash_token);
1561 	}
1562 	return(count);
1563 }
1564 
1565 int
1566 vcount(struct vnode *vp)
1567 {
1568 	if (vp->v_rdev == NULL)
1569 		return(0);
1570 	return(count_dev(vp->v_rdev));
1571 }
1572 
1573 /*
1574  * Initialize VMIO for a vnode.  This routine MUST be called before a
1575  * VFS can issue buffer cache ops on a vnode.  It is typically called
1576  * when a vnode is initialized from its inode.
1577  */
1578 int
1579 vinitvmio(struct vnode *vp, off_t filesize, int blksize, int boff)
1580 {
1581 	vm_object_t object;
1582 	int error = 0;
1583 
1584 	object = vp->v_object;
1585 	if (object) {
1586 		vm_object_hold(object);
1587 		KKASSERT(vp->v_object == object);
1588 	}
1589 
1590 	if (object == NULL) {
1591 		object = vnode_pager_alloc(vp, filesize, 0, 0, blksize, boff);
1592 
1593 		/*
1594 		 * Dereference the reference we just created.  This assumes
1595 		 * that the object is associated with the vp.  Allow it to
1596 		 * have zero refs.  It cannot be destroyed as long as it
1597 		 * is associated with the vnode.
1598 		 */
1599 		vm_object_hold(object);
1600 		atomic_add_int(&object->ref_count, -1);
1601 		vrele(vp);
1602 	} else {
1603 		KKASSERT((object->flags & OBJ_DEAD) == 0);
1604 	}
1605 	KASSERT(vp->v_object != NULL, ("vinitvmio: NULL object"));
1606 	vsetflags(vp, VOBJBUF);
1607 	vm_object_drop(object);
1608 
1609 	return (error);
1610 }
1611 
1612 
1613 /*
1614  * Print out a description of a vnode.
1615  */
1616 static char *typename[] =
1617 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
1618 
1619 void
1620 vprint(char *label, struct vnode *vp)
1621 {
1622 	char buf[96];
1623 
1624 	if (label != NULL)
1625 		kprintf("%s: %p: ", label, (void *)vp);
1626 	else
1627 		kprintf("%p: ", (void *)vp);
1628 	kprintf("type %s, refcnt %08x, writecount %d, holdcnt %d,",
1629 		typename[vp->v_type],
1630 		vp->v_refcnt, vp->v_writecount, vp->v_auxrefs);
1631 	buf[0] = '\0';
1632 	if (vp->v_flag & VROOT)
1633 		strcat(buf, "|VROOT");
1634 	if (vp->v_flag & VPFSROOT)
1635 		strcat(buf, "|VPFSROOT");
1636 	if (vp->v_flag & VTEXT)
1637 		strcat(buf, "|VTEXT");
1638 	if (vp->v_flag & VSYSTEM)
1639 		strcat(buf, "|VSYSTEM");
1640 	if (vp->v_flag & VOBJBUF)
1641 		strcat(buf, "|VOBJBUF");
1642 	if (buf[0] != '\0')
1643 		kprintf(" flags (%s)", &buf[1]);
1644 	if (vp->v_data == NULL) {
1645 		kprintf("\n");
1646 	} else {
1647 		kprintf("\n\t");
1648 		VOP_PRINT(vp);
1649 	}
1650 }
1651 
1652 /*
1653  * Do the usual access checking.
1654  * file_mode, uid and gid are from the vnode in question,
1655  * while acc_mode and cred are from the VOP_ACCESS parameter list
1656  */
1657 int
1658 vaccess(enum vtype type, mode_t file_mode, uid_t uid, gid_t gid,
1659     mode_t acc_mode, struct ucred *cred)
1660 {
1661 	mode_t mask;
1662 	int ismember;
1663 
1664 	/*
1665 	 * Super-user always gets read/write access, but execute access depends
1666 	 * on at least one execute bit being set.
1667 	 */
1668 	if (priv_check_cred(cred, PRIV_ROOT, 0) == 0) {
1669 		if ((acc_mode & VEXEC) && type != VDIR &&
1670 		    (file_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)
1671 			return (EACCES);
1672 		return (0);
1673 	}
1674 
1675 	mask = 0;
1676 
1677 	/* Otherwise, check the owner. */
1678 	if (cred->cr_uid == uid) {
1679 		if (acc_mode & VEXEC)
1680 			mask |= S_IXUSR;
1681 		if (acc_mode & VREAD)
1682 			mask |= S_IRUSR;
1683 		if (acc_mode & VWRITE)
1684 			mask |= S_IWUSR;
1685 		return ((file_mode & mask) == mask ? 0 : EACCES);
1686 	}
1687 
1688 	/* Otherwise, check the groups. */
1689 	ismember = groupmember(gid, cred);
1690 	if (cred->cr_svgid == gid || ismember) {
1691 		if (acc_mode & VEXEC)
1692 			mask |= S_IXGRP;
1693 		if (acc_mode & VREAD)
1694 			mask |= S_IRGRP;
1695 		if (acc_mode & VWRITE)
1696 			mask |= S_IWGRP;
1697 		return ((file_mode & mask) == mask ? 0 : EACCES);
1698 	}
1699 
1700 	/* Otherwise, check everyone else. */
1701 	if (acc_mode & VEXEC)
1702 		mask |= S_IXOTH;
1703 	if (acc_mode & VREAD)
1704 		mask |= S_IROTH;
1705 	if (acc_mode & VWRITE)
1706 		mask |= S_IWOTH;
1707 	return ((file_mode & mask) == mask ? 0 : EACCES);
1708 }
1709 
1710 #ifdef DDB
1711 #include <ddb/ddb.h>
1712 
1713 static int db_show_locked_vnodes(struct mount *mp, void *data);
1714 
1715 /*
1716  * List all of the locked vnodes in the system.
1717  * Called when debugging the kernel.
1718  */
1719 DB_SHOW_COMMAND(lockedvnodes, lockedvnodes)
1720 {
1721 	kprintf("Locked vnodes\n");
1722 	mountlist_scan(db_show_locked_vnodes, NULL,
1723 			MNTSCAN_FORWARD|MNTSCAN_NOBUSY);
1724 }
1725 
1726 static int
1727 db_show_locked_vnodes(struct mount *mp, void *data __unused)
1728 {
1729 	struct vnode *vp;
1730 
1731 	TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
1732 		if (vn_islocked(vp))
1733 			vprint(NULL, vp);
1734 	}
1735 	return(0);
1736 }
1737 #endif
1738 
1739 /*
1740  * Top level filesystem related information gathering.
1741  */
1742 static int	sysctl_ovfs_conf (SYSCTL_HANDLER_ARGS);
1743 
1744 static int
1745 vfs_sysctl(SYSCTL_HANDLER_ARGS)
1746 {
1747 	int *name = (int *)arg1 - 1;	/* XXX */
1748 	u_int namelen = arg2 + 1;	/* XXX */
1749 	struct vfsconf *vfsp;
1750 	int maxtypenum;
1751 
1752 #if 1 || defined(COMPAT_PRELITE2)
1753 	/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
1754 	if (namelen == 1)
1755 		return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
1756 #endif
1757 
1758 #ifdef notyet
1759 	/* all sysctl names at this level are at least name and field */
1760 	if (namelen < 2)
1761 		return (ENOTDIR);		/* overloaded */
1762 	if (name[0] != VFS_GENERIC) {
1763 		vfsp = vfsconf_find_by_typenum(name[0]);
1764 		if (vfsp == NULL)
1765 			return (EOPNOTSUPP);
1766 		return ((*vfsp->vfc_vfsops->vfs_sysctl)(&name[1], namelen - 1,
1767 		    oldp, oldlenp, newp, newlen, p));
1768 	}
1769 #endif
1770 	switch (name[1]) {
1771 	case VFS_MAXTYPENUM:
1772 		if (namelen != 2)
1773 			return (ENOTDIR);
1774 		maxtypenum = vfsconf_get_maxtypenum();
1775 		return (SYSCTL_OUT(req, &maxtypenum, sizeof(maxtypenum)));
1776 	case VFS_CONF:
1777 		if (namelen != 3)
1778 			return (ENOTDIR);	/* overloaded */
1779 		vfsp = vfsconf_find_by_typenum(name[2]);
1780 		if (vfsp == NULL)
1781 			return (EOPNOTSUPP);
1782 		return (SYSCTL_OUT(req, vfsp, sizeof *vfsp));
1783 	}
1784 	return (EOPNOTSUPP);
1785 }
1786 
1787 SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD, vfs_sysctl,
1788 	"Generic filesystem");
1789 
1790 #if 1 || defined(COMPAT_PRELITE2)
1791 
1792 static int
1793 sysctl_ovfs_conf_iter(struct vfsconf *vfsp, void *data)
1794 {
1795 	int error;
1796 	struct ovfsconf ovfs;
1797 	struct sysctl_req *req = (struct sysctl_req*) data;
1798 
1799 	bzero(&ovfs, sizeof(ovfs));
1800 	ovfs.vfc_vfsops = vfsp->vfc_vfsops;	/* XXX used as flag */
1801 	strcpy(ovfs.vfc_name, vfsp->vfc_name);
1802 	ovfs.vfc_index = vfsp->vfc_typenum;
1803 	ovfs.vfc_refcount = vfsp->vfc_refcount;
1804 	ovfs.vfc_flags = vfsp->vfc_flags;
1805 	error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
1806 	if (error)
1807 		return error; /* abort iteration with error code */
1808 	else
1809 		return 0; /* continue iterating with next element */
1810 }
1811 
1812 static int
1813 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
1814 {
1815 	return vfsconf_each(sysctl_ovfs_conf_iter, (void*)req);
1816 }
1817 
1818 #endif /* 1 || COMPAT_PRELITE2 */
1819 
1820 /*
1821  * Check to see if a filesystem is mounted on a block device.
1822  */
1823 int
1824 vfs_mountedon(struct vnode *vp)
1825 {
1826 	cdev_t dev;
1827 
1828 	if ((dev = vp->v_rdev) == NULL) {
1829 /*		if (vp->v_type != VBLK)
1830 			dev = get_dev(vp->v_uminor, vp->v_umajor); */
1831 	}
1832 	if (dev != NULL && dev->si_mountpoint)
1833 		return (EBUSY);
1834 	return (0);
1835 }
1836 
1837 /*
1838  * Unmount all filesystems. The list is traversed in reverse order
1839  * of mounting to avoid dependencies.
1840  *
1841  * We want the umountall to be able to break out of its loop if a
1842  * failure occurs, after scanning all possible mounts, so the callback
1843  * returns 0 on error.
1844  *
1845  * NOTE: Do not call mountlist_remove(mp) on error any more, this will
1846  *	 confuse mountlist_scan()'s unbusy check.
1847  */
1848 static int vfs_umountall_callback(struct mount *mp, void *data);
1849 
1850 void
1851 vfs_unmountall(void)
1852 {
1853 	int count;
1854 
1855 	do {
1856 		count = mountlist_scan(vfs_umountall_callback,
1857 					NULL, MNTSCAN_REVERSE|MNTSCAN_NOBUSY);
1858 	} while (count);
1859 }
1860 
1861 static
1862 int
1863 vfs_umountall_callback(struct mount *mp, void *data)
1864 {
1865 	int error;
1866 
1867 	error = dounmount(mp, MNT_FORCE);
1868 	if (error) {
1869 		kprintf("unmount of filesystem mounted from %s failed (",
1870 			mp->mnt_stat.f_mntfromname);
1871 		if (error == EBUSY)
1872 			kprintf("BUSY)\n");
1873 		else
1874 			kprintf("%d)\n", error);
1875 		return 0;
1876 	} else {
1877 		return 1;
1878 	}
1879 }
1880 
1881 /*
1882  * Checks the mount flags for parameter mp and put the names comma-separated
1883  * into a string buffer buf with a size limit specified by len.
1884  *
1885  * It returns the number of bytes written into buf, and (*errorp) will be
1886  * set to 0, EINVAL (if passed length is 0), or ENOSPC (supplied buffer was
1887  * not large enough).  The buffer will be 0-terminated if len was not 0.
1888  */
1889 size_t
1890 vfs_flagstostr(int flags, const struct mountctl_opt *optp,
1891 	       char *buf, size_t len, int *errorp)
1892 {
1893 	static const struct mountctl_opt optnames[] = {
1894 		{ MNT_RDONLY,           "read-only" },
1895 		{ MNT_SYNCHRONOUS,      "synchronous" },
1896 		{ MNT_NOEXEC,           "noexec" },
1897 		{ MNT_NOSUID,           "nosuid" },
1898 		{ MNT_NODEV,            "nodev" },
1899 		{ MNT_AUTOMOUNTED,      "automounted" },
1900 		{ MNT_ASYNC,            "asynchronous" },
1901 		{ MNT_SUIDDIR,          "suiddir" },
1902 		{ MNT_SOFTDEP,          "soft-updates" },
1903 		{ MNT_NOSYMFOLLOW,      "nosymfollow" },
1904 		{ MNT_TRIM,             "trim" },
1905 		{ MNT_NOATIME,          "noatime" },
1906 		{ MNT_NOCLUSTERR,       "noclusterr" },
1907 		{ MNT_NOCLUSTERW,       "noclusterw" },
1908 		{ MNT_EXRDONLY,         "NFS read-only" },
1909 		{ MNT_EXPORTED,         "NFS exported" },
1910 		/* Remaining NFS flags could come here */
1911 		{ MNT_LOCAL,            "local" },
1912 		{ MNT_QUOTA,            "with-quotas" },
1913 		/* { MNT_ROOTFS,           "rootfs" }, */
1914 		/* { MNT_IGNORE,           "ignore" }, */
1915 		{ 0,			NULL}
1916 	};
1917 	int bwritten;
1918 	int bleft;
1919 	int optlen;
1920 	int actsize;
1921 
1922 	*errorp = 0;
1923 	bwritten = 0;
1924 	bleft = len - 1;	/* leave room for trailing \0 */
1925 
1926 	/*
1927 	 * Checks the size of the string. If it contains
1928 	 * any data, then we will append the new flags to
1929 	 * it.
1930 	 */
1931 	actsize = strlen(buf);
1932 	if (actsize > 0)
1933 		buf += actsize;
1934 
1935 	/* Default flags if no flags passed */
1936 	if (optp == NULL)
1937 		optp = optnames;
1938 
1939 	if (bleft < 0) {	/* degenerate case, 0-length buffer */
1940 		*errorp = EINVAL;
1941 		return(0);
1942 	}
1943 
1944 	for (; flags && optp->o_opt; ++optp) {
1945 		if ((flags & optp->o_opt) == 0)
1946 			continue;
1947 		optlen = strlen(optp->o_name);
1948 		if (bwritten || actsize > 0) {
1949 			if (bleft < 2) {
1950 				*errorp = ENOSPC;
1951 				break;
1952 			}
1953 			buf[bwritten++] = ',';
1954 			buf[bwritten++] = ' ';
1955 			bleft -= 2;
1956 		}
1957 		if (bleft < optlen) {
1958 			*errorp = ENOSPC;
1959 			break;
1960 		}
1961 		bcopy(optp->o_name, buf + bwritten, optlen);
1962 		bwritten += optlen;
1963 		bleft -= optlen;
1964 		flags &= ~optp->o_opt;
1965 	}
1966 
1967 	/*
1968 	 * Space already reserved for trailing \0
1969 	 */
1970 	buf[bwritten] = 0;
1971 	return (bwritten);
1972 }
1973 
1974 /*
1975  * Build hash lists of net addresses and hang them off the mount point.
1976  * Called by ufs_mount() to set up the lists of export addresses.
1977  */
1978 static int
1979 vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
1980 		const struct export_args *argp)
1981 {
1982 	struct netcred *np;
1983 	struct radix_node_head *rnh;
1984 	int i;
1985 	struct radix_node *rn;
1986 	struct sockaddr *saddr, *smask = NULL;
1987 	int error;
1988 
1989 	if (argp->ex_addrlen == 0) {
1990 		if (mp->mnt_flag & MNT_DEFEXPORTED)
1991 			return (EPERM);
1992 		np = &nep->ne_defexported;
1993 		np->netc_exflags = argp->ex_flags;
1994 		np->netc_anon = argp->ex_anon;
1995 		np->netc_anon.cr_ref = 1;
1996 		mp->mnt_flag |= MNT_DEFEXPORTED;
1997 		return (0);
1998 	}
1999 
2000 	if (argp->ex_addrlen < 0 || argp->ex_addrlen > MLEN)
2001 		return (EINVAL);
2002 	if (argp->ex_masklen < 0 || argp->ex_masklen > MLEN)
2003 		return (EINVAL);
2004 
2005 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
2006 	np = (struct netcred *) kmalloc(i, M_NETADDR, M_WAITOK | M_ZERO);
2007 	saddr = (struct sockaddr *) (np + 1);
2008 	if ((error = copyin(argp->ex_addr, (caddr_t) saddr, argp->ex_addrlen)))
2009 		goto out;
2010 	if (saddr->sa_len > argp->ex_addrlen)
2011 		saddr->sa_len = argp->ex_addrlen;
2012 	if (argp->ex_masklen) {
2013 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
2014 		error = copyin(argp->ex_mask, (caddr_t)smask, argp->ex_masklen);
2015 		if (error)
2016 			goto out;
2017 		if (smask->sa_len > argp->ex_masklen)
2018 			smask->sa_len = argp->ex_masklen;
2019 	}
2020 	NE_LOCK(nep);
2021 	if (nep->ne_maskhead == NULL) {
2022 		if (!rn_inithead((void **)&nep->ne_maskhead, NULL, 0)) {
2023 			error = ENOBUFS;
2024 			goto out;
2025 		}
2026 	}
2027 	if((rnh = vfs_create_addrlist_af(saddr->sa_family, nep)) == NULL) {
2028 		error = ENOBUFS;
2029 		goto out;
2030 	}
2031 	rn = (*rnh->rnh_addaddr) ((char *) saddr, (char *) smask, rnh,
2032 	    np->netc_rnodes);
2033 	NE_UNLOCK(nep);
2034 	if (rn == NULL || np != (struct netcred *) rn) {	/* already exists */
2035 		error = EPERM;
2036 		goto out;
2037 	}
2038 	np->netc_exflags = argp->ex_flags;
2039 	np->netc_anon = argp->ex_anon;
2040 	np->netc_anon.cr_ref = 1;
2041 	return (0);
2042 out:
2043 	kfree(np, M_NETADDR);
2044 	return (error);
2045 }
2046 
2047 /* ARGSUSED */
2048 static int
2049 vfs_free_netcred(struct radix_node *rn, void *w)
2050 {
2051 	struct radix_node_head *rnh = (struct radix_node_head *) w;
2052 
2053 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
2054 	kfree((caddr_t) rn, M_NETADDR);
2055 	return (0);
2056 }
2057 
2058 static struct radix_node_head *
2059 vfs_create_addrlist_af(int af, struct netexport *nep)
2060 {
2061 	struct radix_node_head *rnh = NULL;
2062 #if defined(INET) || defined(INET6)
2063 	struct radix_node_head *maskhead = nep->ne_maskhead;
2064 	int off;
2065 #endif
2066 
2067 	NE_ASSERT_LOCKED(nep);
2068 	KKASSERT(maskhead != NULL);
2069 	switch (af) {
2070 #ifdef INET
2071 	case AF_INET:
2072 		if ((rnh = nep->ne_inethead) == NULL) {
2073 			off = offsetof(struct sockaddr_in, sin_addr) << 3;
2074 			if (!rn_inithead((void **)&rnh, maskhead, off))
2075 				return (NULL);
2076 			nep->ne_inethead = rnh;
2077 		}
2078 		break;
2079 #endif
2080 #ifdef INET6
2081 	case AF_INET6:
2082 		if ((rnh = nep->ne_inet6head) == NULL) {
2083 			off = offsetof(struct sockaddr_in6, sin6_addr) << 3;
2084 			if (!rn_inithead((void **)&rnh, maskhead, off))
2085 				return (NULL);
2086 			nep->ne_inet6head = rnh;
2087 		}
2088 		break;
2089 #endif
2090 	}
2091 	return (rnh);
2092 }
2093 
2094 static void
2095 vfs_free_addrlist_af(struct radix_node_head **prnh)
2096 {
2097 	struct radix_node_head *rnh = *prnh;
2098 
2099 	(*rnh->rnh_walktree) (rnh, vfs_free_netcred, rnh);
2100 	kfree(rnh, M_RTABLE);
2101 	*prnh = NULL;
2102 }
2103 
2104 /*
2105  * Free the net address hash lists that are hanging off the mount points.
2106  */
2107 static void
2108 vfs_free_addrlist(struct netexport *nep)
2109 {
2110 	NE_LOCK(nep);
2111 	if (nep->ne_inethead != NULL)
2112 		vfs_free_addrlist_af(&nep->ne_inethead);
2113 	if (nep->ne_inet6head != NULL)
2114 		vfs_free_addrlist_af(&nep->ne_inet6head);
2115 	if (nep->ne_maskhead)
2116 		vfs_free_addrlist_af(&nep->ne_maskhead);
2117 	NE_UNLOCK(nep);
2118 }
2119 
2120 int
2121 vfs_export(struct mount *mp, struct netexport *nep,
2122 	   const struct export_args *argp)
2123 {
2124 	int error;
2125 
2126 	if (argp->ex_flags & MNT_DELEXPORT) {
2127 		if (mp->mnt_flag & MNT_EXPUBLIC) {
2128 			vfs_setpublicfs(NULL, NULL, NULL);
2129 			mp->mnt_flag &= ~MNT_EXPUBLIC;
2130 		}
2131 		vfs_free_addrlist(nep);
2132 		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
2133 	}
2134 	if (argp->ex_flags & MNT_EXPORTED) {
2135 		if (argp->ex_flags & MNT_EXPUBLIC) {
2136 			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
2137 				return (error);
2138 			mp->mnt_flag |= MNT_EXPUBLIC;
2139 		}
2140 		if ((error = vfs_hang_addrlist(mp, nep, argp)))
2141 			return (error);
2142 		mp->mnt_flag |= MNT_EXPORTED;
2143 	}
2144 	return (0);
2145 }
2146 
2147 
2148 /*
2149  * Set the publicly exported filesystem (WebNFS). Currently, only
2150  * one public filesystem is possible in the spec (RFC 2054 and 2055)
2151  */
2152 int
2153 vfs_setpublicfs(struct mount *mp, struct netexport *nep,
2154 		const struct export_args *argp)
2155 {
2156 	int error;
2157 	struct vnode *rvp;
2158 	char *cp;
2159 
2160 	/*
2161 	 * mp == NULL -> invalidate the current info, the FS is
2162 	 * no longer exported. May be called from either vfs_export
2163 	 * or unmount, so check if it hasn't already been done.
2164 	 */
2165 	if (mp == NULL) {
2166 		if (nfs_pub.np_valid) {
2167 			nfs_pub.np_valid = 0;
2168 			if (nfs_pub.np_index != NULL) {
2169 				kfree(nfs_pub.np_index, M_TEMP);
2170 				nfs_pub.np_index = NULL;
2171 			}
2172 		}
2173 		return (0);
2174 	}
2175 
2176 	/*
2177 	 * Only one allowed at a time.
2178 	 */
2179 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
2180 		return (EBUSY);
2181 
2182 	/*
2183 	 * Get real filehandle for root of exported FS.
2184 	 */
2185 	bzero((caddr_t)&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
2186 	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
2187 
2188 	if ((error = VFS_ROOT(mp, &rvp)))
2189 		return (error);
2190 
2191 	if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
2192 		return (error);
2193 
2194 	vput(rvp);
2195 
2196 	/*
2197 	 * If an indexfile was specified, pull it in.
2198 	 */
2199 	if (argp->ex_indexfile != NULL) {
2200 		int namelen;
2201 
2202 		error = vn_get_namelen(rvp, &namelen);
2203 		if (error)
2204 			return (error);
2205 		nfs_pub.np_index = kmalloc(namelen, M_TEMP, M_WAITOK);
2206 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
2207 		    namelen, NULL);
2208 		if (!error) {
2209 			/*
2210 			 * Check for illegal filenames.
2211 			 */
2212 			for (cp = nfs_pub.np_index; *cp; cp++) {
2213 				if (*cp == '/') {
2214 					error = EINVAL;
2215 					break;
2216 				}
2217 			}
2218 		}
2219 		if (error) {
2220 			kfree(nfs_pub.np_index, M_TEMP);
2221 			return (error);
2222 		}
2223 	}
2224 
2225 	nfs_pub.np_mount = mp;
2226 	nfs_pub.np_valid = 1;
2227 	return (0);
2228 }
2229 
2230 struct netcred *
2231 vfs_export_lookup(struct mount *mp, struct netexport *nep,
2232 		struct sockaddr *nam)
2233 {
2234 	struct netcred *np;
2235 	struct radix_node_head *rnh;
2236 	struct sockaddr *saddr;
2237 
2238 	np = NULL;
2239 	if (mp->mnt_flag & MNT_EXPORTED) {
2240 		/*
2241 		 * Lookup in the export list first.
2242 		 */
2243 		NE_LOCK(nep);
2244 		if (nam != NULL) {
2245 			saddr = nam;
2246 			switch (saddr->sa_family) {
2247 #ifdef INET
2248 			case AF_INET:
2249 				rnh = nep->ne_inethead;
2250 				break;
2251 #endif
2252 #ifdef INET6
2253 			case AF_INET6:
2254 				rnh = nep->ne_inet6head;
2255 				break;
2256 #endif
2257 			default:
2258 				rnh = NULL;
2259 			}
2260 			if (rnh != NULL) {
2261 				np = (struct netcred *)
2262 					(*rnh->rnh_matchaddr)((char *)saddr,
2263 							      rnh);
2264 				if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
2265 					np = NULL;
2266 			}
2267 		}
2268 		NE_UNLOCK(nep);
2269 		/*
2270 		 * If no address match, use the default if it exists.
2271 		 */
2272 		if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
2273 			np = &nep->ne_defexported;
2274 	}
2275 	return (np);
2276 }
2277 
2278 /*
2279  * perform msync on all vnodes under a mount point.  The mount point must
2280  * be locked.  This code is also responsible for lazy-freeing unreferenced
2281  * vnodes whos VM objects no longer contain pages.
2282  *
2283  * NOTE: MNT_WAIT still skips vnodes in the VXLOCK state.
2284  *
2285  * NOTE: XXX VOP_PUTPAGES and friends requires that the vnode be locked,
2286  * but vnode_pager_putpages() doesn't lock the vnode.  We have to do it
2287  * way up in this high level function.
2288  */
2289 static int vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data);
2290 static int vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data);
2291 
2292 void
2293 vfs_msync(struct mount *mp, int flags)
2294 {
2295 	int vmsc_flags;
2296 
2297 	/*
2298 	 * tmpfs sets this flag to prevent msync(), sync, and the
2299 	 * filesystem periodic syncer from trying to flush VM pages
2300 	 * to swap.  Only pure memory pressure flushes tmpfs VM pages
2301 	 * to swap.
2302 	 */
2303 	if (mp->mnt_kern_flag & MNTK_NOMSYNC)
2304 		return;
2305 
2306 	/*
2307 	 * Ok, scan the vnodes for work.  If the filesystem is using the
2308 	 * syncer thread feature we can use vsyncscan() instead of
2309 	 * vmntvnodescan(), which is much faster.
2310 	 */
2311 	vmsc_flags = VMSC_GETVP;
2312 	if (flags != MNT_WAIT)
2313 		vmsc_flags |= VMSC_NOWAIT;
2314 
2315 	if (mp->mnt_kern_flag & MNTK_THR_SYNC) {
2316 		vsyncscan(mp, vmsc_flags, vfs_msync_scan2,
2317 			  (void *)(intptr_t)flags);
2318 	} else {
2319 		vmntvnodescan(mp, vmsc_flags,
2320 			      vfs_msync_scan1, vfs_msync_scan2,
2321 			      (void *)(intptr_t)flags);
2322 	}
2323 }
2324 
2325 /*
2326  * scan1 is a fast pre-check.  There could be hundreds of thousands of
2327  * vnodes, we cannot afford to do anything heavy weight until we have a
2328  * fairly good indication that there is work to do.
2329  */
2330 static
2331 int
2332 vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data)
2333 {
2334 	int flags = (int)(intptr_t)data;
2335 
2336 	if ((vp->v_flag & VRECLAIMED) == 0) {
2337 		if (vp->v_auxrefs == 0 && VREFCNT(vp) <= 0 &&
2338 		    vp->v_object) {
2339 			return(0);	/* call scan2 */
2340 		}
2341 		if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
2342 		    (vp->v_flag & VOBJDIRTY) &&
2343 		    (flags == MNT_WAIT || vn_islocked(vp) == 0)) {
2344 			return(0);	/* call scan2 */
2345 		}
2346 	}
2347 
2348 	/*
2349 	 * do not call scan2, continue the loop
2350 	 */
2351 	return(-1);
2352 }
2353 
2354 /*
2355  * This callback is handed a locked vnode.
2356  */
2357 static
2358 int
2359 vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data)
2360 {
2361 	vm_object_t obj;
2362 	int flags = (int)(intptr_t)data;
2363 
2364 	if (vp->v_flag & VRECLAIMED)
2365 		return(0);
2366 
2367 	if ((mp->mnt_flag & MNT_RDONLY) == 0 && (vp->v_flag & VOBJDIRTY)) {
2368 		if ((obj = vp->v_object) != NULL) {
2369 			vm_object_page_clean(obj, 0, 0,
2370 			 flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
2371 		}
2372 	}
2373 	return(0);
2374 }
2375 
2376 /*
2377  * Wake up anyone interested in vp because it is being revoked.
2378  */
2379 void
2380 vn_gone(struct vnode *vp)
2381 {
2382 	lwkt_gettoken(&vp->v_token);
2383 	KNOTE(&vp->v_pollinfo.vpi_kqinfo.ki_note, NOTE_REVOKE);
2384 	lwkt_reltoken(&vp->v_token);
2385 }
2386 
2387 /*
2388  * extract the cdev_t from a VBLK or VCHR.  The vnode must have been opened
2389  * (or v_rdev might be NULL).
2390  */
2391 cdev_t
2392 vn_todev(struct vnode *vp)
2393 {
2394 	if (vp->v_type != VBLK && vp->v_type != VCHR)
2395 		return (NULL);
2396 	KKASSERT(vp->v_rdev != NULL);
2397 	return (vp->v_rdev);
2398 }
2399 
2400 /*
2401  * Check if vnode represents a disk device.  The vnode does not need to be
2402  * opened.
2403  *
2404  * MPALMOSTSAFE
2405  */
2406 int
2407 vn_isdisk(struct vnode *vp, int *errp)
2408 {
2409 	cdev_t dev;
2410 
2411 	if (vp->v_type != VCHR) {
2412 		if (errp != NULL)
2413 			*errp = ENOTBLK;
2414 		return (0);
2415 	}
2416 
2417 	dev = vp->v_rdev;
2418 
2419 	if (dev == NULL) {
2420 		if (errp != NULL)
2421 			*errp = ENXIO;
2422 		return (0);
2423 	}
2424 	if (dev_is_good(dev) == 0) {
2425 		if (errp != NULL)
2426 			*errp = ENXIO;
2427 		return (0);
2428 	}
2429 	if ((dev_dflags(dev) & D_DISK) == 0) {
2430 		if (errp != NULL)
2431 			*errp = ENOTBLK;
2432 		return (0);
2433 	}
2434 	if (errp != NULL)
2435 		*errp = 0;
2436 	return (1);
2437 }
2438 
2439 int
2440 vn_get_namelen(struct vnode *vp, int *namelen)
2441 {
2442 	int error;
2443 	register_t retval[2];
2444 
2445 	error = VOP_PATHCONF(vp, _PC_NAME_MAX, retval);
2446 	if (error)
2447 		return (error);
2448 	*namelen = (int)retval[0];
2449 	return (0);
2450 }
2451 
2452 int
2453 vop_write_dirent(int *error, struct uio *uio, ino_t d_ino, uint8_t d_type,
2454 		uint16_t d_namlen, const char *d_name)
2455 {
2456 	struct dirent *dp;
2457 	size_t len;
2458 
2459 	len = _DIRENT_RECLEN(d_namlen);
2460 	if (len > uio->uio_resid)
2461 		return(1);
2462 
2463 	dp = kmalloc(len, M_TEMP, M_WAITOK | M_ZERO);
2464 
2465 	dp->d_ino = d_ino;
2466 	dp->d_namlen = d_namlen;
2467 	dp->d_type = d_type;
2468 	bcopy(d_name, dp->d_name, d_namlen);
2469 
2470 	*error = uiomove((caddr_t)dp, len, uio);
2471 
2472 	kfree(dp, M_TEMP);
2473 
2474 	return(0);
2475 }
2476 
2477 void
2478 vn_mark_atime(struct vnode *vp, struct thread *td)
2479 {
2480 	struct proc *p = td->td_proc;
2481 	struct ucred *cred = p ? p->p_ucred : proc0.p_ucred;
2482 
2483 	if ((vp->v_mount->mnt_flag & (MNT_NOATIME | MNT_RDONLY)) == 0) {
2484 		VOP_MARKATIME(vp, cred);
2485 	}
2486 }
2487 
2488 /*
2489  * Calculate the number of entries in an inode-related chained hash table.
2490  * With today's memory sizes, maxvnodes can wind up being a very large
2491  * number.  There is no reason to waste memory, so tolerate some stacking.
2492  */
2493 int
2494 vfs_inodehashsize(void)
2495 {
2496 	int hsize;
2497 
2498 	hsize = 32;
2499 	while (hsize < maxvnodes)
2500 		hsize <<= 1;
2501 	while (hsize > maxvnodes * 2)
2502 		hsize >>= 1;		/* nominal 2x stacking */
2503 
2504 	if (maxvnodes > 1024 * 1024)
2505 		hsize >>= 1;		/* nominal 8x stacking */
2506 
2507 	if (maxvnodes > 128 * 1024)
2508 		hsize >>= 1;		/* nominal 4x stacking */
2509 
2510 	if (hsize < 16)
2511 		hsize = 16;
2512 
2513 	return hsize;
2514 }
2515