xref: /dragonfly/sys/kern/vfs_subr.c (revision 783d47c4)
1 /*
2  * Copyright (c) 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)vfs_subr.c	8.31 (Berkeley) 5/26/95
39  * $FreeBSD: src/sys/kern/vfs_subr.c,v 1.249.2.30 2003/04/04 20:35:57 tegge Exp $
40  */
41 
42 /*
43  * External virtual filesystem routines
44  */
45 #include "opt_ddb.h"
46 
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/buf.h>
50 #include <sys/conf.h>
51 #include <sys/dirent.h>
52 #include <sys/domain.h>
53 #include <sys/eventhandler.h>
54 #include <sys/fcntl.h>
55 #include <sys/file.h>
56 #include <sys/kernel.h>
57 #include <sys/kthread.h>
58 #include <sys/malloc.h>
59 #include <sys/mbuf.h>
60 #include <sys/mount.h>
61 #include <sys/priv.h>
62 #include <sys/proc.h>
63 #include <sys/reboot.h>
64 #include <sys/socket.h>
65 #include <sys/stat.h>
66 #include <sys/sysctl.h>
67 #include <sys/syslog.h>
68 #include <sys/unistd.h>
69 #include <sys/vmmeter.h>
70 #include <sys/vnode.h>
71 
72 #include <machine/limits.h>
73 
74 #include <vm/vm.h>
75 #include <vm/vm_object.h>
76 #include <vm/vm_extern.h>
77 #include <vm/vm_kern.h>
78 #include <vm/pmap.h>
79 #include <vm/vm_map.h>
80 #include <vm/vm_page.h>
81 #include <vm/vm_pager.h>
82 #include <vm/vnode_pager.h>
83 #include <vm/vm_zone.h>
84 
85 #include <sys/buf2.h>
86 #include <sys/thread2.h>
87 #include <sys/sysref2.h>
88 #include <sys/mplock2.h>
89 
90 static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
91 
92 int numvnodes;
93 SYSCTL_INT(_debug, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0,
94     "Number of vnodes allocated");
95 int verbose_reclaims;
96 SYSCTL_INT(_debug, OID_AUTO, verbose_reclaims, CTLFLAG_RD, &verbose_reclaims, 0,
97     "Output filename of reclaimed vnode(s)");
98 
99 enum vtype iftovt_tab[16] = {
100 	VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
101 	VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
102 };
103 int vttoif_tab[9] = {
104 	0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
105 	S_IFSOCK, S_IFIFO, S_IFMT,
106 };
107 
108 static int reassignbufcalls;
109 SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW, &reassignbufcalls,
110     0, "Number of times buffers have been reassigned to the proper list");
111 
112 static int check_buf_overlap = 2;	/* invasive check */
113 SYSCTL_INT(_vfs, OID_AUTO, check_buf_overlap, CTLFLAG_RW, &check_buf_overlap,
114     0, "Enable overlapping buffer checks");
115 
116 int	nfs_mount_type = -1;
117 static struct lwkt_token spechash_token;
118 struct nfs_public nfs_pub;	/* publicly exported FS */
119 
120 int desiredvnodes;
121 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
122 		&desiredvnodes, 0, "Maximum number of vnodes");
123 
124 static void	vfs_free_addrlist (struct netexport *nep);
125 static int	vfs_free_netcred (struct radix_node *rn, void *w);
126 static int	vfs_hang_addrlist (struct mount *mp, struct netexport *nep,
127 				       const struct export_args *argp);
128 
129 /*
130  * Red black tree functions
131  */
132 static int rb_buf_compare(struct buf *b1, struct buf *b2);
133 RB_GENERATE2(buf_rb_tree, buf, b_rbnode, rb_buf_compare, off_t, b_loffset);
134 RB_GENERATE2(buf_rb_hash, buf, b_rbhash, rb_buf_compare, off_t, b_loffset);
135 
136 static int
137 rb_buf_compare(struct buf *b1, struct buf *b2)
138 {
139 	if (b1->b_loffset < b2->b_loffset)
140 		return(-1);
141 	if (b1->b_loffset > b2->b_loffset)
142 		return(1);
143 	return(0);
144 }
145 
146 /*
147  * Returns non-zero if the vnode is a candidate for lazy msyncing.
148  *
149  * NOTE: v_object is not stable (this scan can race), however the
150  *	 mntvnodescan code holds vmobj_token so any VM object we
151  *	 do find will remain stable storage.
152  */
153 static __inline int
154 vshouldmsync(struct vnode *vp)
155 {
156 	vm_object_t object;
157 
158 	if (vp->v_auxrefs != 0 || vp->v_sysref.refcnt > 0)
159 		return (0);		/* other holders */
160 	object = vp->v_object;
161 	cpu_ccfence();
162 	if (object && (object->ref_count || object->resident_page_count))
163 		return(0);
164 	return (1);
165 }
166 
167 /*
168  * Initialize the vnode management data structures.
169  *
170  * Called from vfsinit()
171  */
172 void
173 vfs_subr_init(void)
174 {
175 	int factor1;
176 	int factor2;
177 
178 	/*
179 	 * Desiredvnodes is kern.maxvnodes.  We want to scale it
180 	 * according to available system memory but we may also have
181 	 * to limit it based on available KVM, which is capped on 32 bit
182 	 * systems.
183 	 *
184 	 * WARNING!  For machines with 64-256M of ram we have to be sure
185 	 *	     that the default limit scales down well due to HAMMER
186 	 *	     taking up significantly more memory per-vnode vs UFS.
187 	 *	     We want around ~5800 on a 128M machine.
188 	 */
189 	factor1 = 20 * (sizeof(struct vm_object) + sizeof(struct vnode));
190 	factor2 = 22 * (sizeof(struct vm_object) + sizeof(struct vnode));
191 	desiredvnodes =
192 		imin((int64_t)vmstats.v_page_count * PAGE_SIZE / factor1,
193 		     KvaSize / factor2);
194 	desiredvnodes = imax(desiredvnodes, maxproc * 8);
195 
196 	lwkt_token_init(&spechash_token, "spechash");
197 }
198 
199 /*
200  * Knob to control the precision of file timestamps:
201  *
202  *   0 = seconds only; nanoseconds zeroed.
203  *   1 = seconds and nanoseconds, accurate within 1/HZ.
204  *   2 = seconds and nanoseconds, truncated to microseconds.
205  * >=3 = seconds and nanoseconds, maximum precision.
206  */
207 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
208 
209 static int timestamp_precision = TSP_SEC;
210 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
211 		&timestamp_precision, 0, "Precision of file timestamps");
212 
213 /*
214  * Get a current timestamp.
215  *
216  * MPSAFE
217  */
218 void
219 vfs_timestamp(struct timespec *tsp)
220 {
221 	struct timeval tv;
222 
223 	switch (timestamp_precision) {
224 	case TSP_SEC:
225 		tsp->tv_sec = time_second;
226 		tsp->tv_nsec = 0;
227 		break;
228 	case TSP_HZ:
229 		getnanotime(tsp);
230 		break;
231 	case TSP_USEC:
232 		microtime(&tv);
233 		TIMEVAL_TO_TIMESPEC(&tv, tsp);
234 		break;
235 	case TSP_NSEC:
236 	default:
237 		nanotime(tsp);
238 		break;
239 	}
240 }
241 
242 /*
243  * Set vnode attributes to VNOVAL
244  */
245 void
246 vattr_null(struct vattr *vap)
247 {
248 	vap->va_type = VNON;
249 	vap->va_size = VNOVAL;
250 	vap->va_bytes = VNOVAL;
251 	vap->va_mode = VNOVAL;
252 	vap->va_nlink = VNOVAL;
253 	vap->va_uid = VNOVAL;
254 	vap->va_gid = VNOVAL;
255 	vap->va_fsid = VNOVAL;
256 	vap->va_fileid = VNOVAL;
257 	vap->va_blocksize = VNOVAL;
258 	vap->va_rmajor = VNOVAL;
259 	vap->va_rminor = VNOVAL;
260 	vap->va_atime.tv_sec = VNOVAL;
261 	vap->va_atime.tv_nsec = VNOVAL;
262 	vap->va_mtime.tv_sec = VNOVAL;
263 	vap->va_mtime.tv_nsec = VNOVAL;
264 	vap->va_ctime.tv_sec = VNOVAL;
265 	vap->va_ctime.tv_nsec = VNOVAL;
266 	vap->va_flags = VNOVAL;
267 	vap->va_gen = VNOVAL;
268 	vap->va_vaflags = 0;
269 	/* va_*_uuid fields are only valid if related flags are set */
270 }
271 
272 /*
273  * Flush out and invalidate all buffers associated with a vnode.
274  *
275  * vp must be locked.
276  */
277 static int vinvalbuf_bp(struct buf *bp, void *data);
278 
279 struct vinvalbuf_bp_info {
280 	struct vnode *vp;
281 	int slptimeo;
282 	int lkflags;
283 	int flags;
284 	int clean;
285 };
286 
287 int
288 vinvalbuf(struct vnode *vp, int flags, int slpflag, int slptimeo)
289 {
290 	struct vinvalbuf_bp_info info;
291 	vm_object_t object;
292 	int error;
293 
294 	lwkt_gettoken(&vp->v_token);
295 
296 	/*
297 	 * If we are being asked to save, call fsync to ensure that the inode
298 	 * is updated.
299 	 */
300 	if (flags & V_SAVE) {
301 		error = bio_track_wait(&vp->v_track_write, slpflag, slptimeo);
302 		if (error)
303 			goto done;
304 		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
305 			if ((error = VOP_FSYNC(vp, MNT_WAIT, 0)) != 0)
306 				goto done;
307 
308 			/*
309 			 * Dirty bufs may be left or generated via races
310 			 * in circumstances where vinvalbuf() is called on
311 			 * a vnode not undergoing reclamation.   Only
312 			 * panic if we are trying to reclaim the vnode.
313 			 */
314 			if ((vp->v_flag & VRECLAIMED) &&
315 			    (bio_track_active(&vp->v_track_write) ||
316 			    !RB_EMPTY(&vp->v_rbdirty_tree))) {
317 				panic("vinvalbuf: dirty bufs");
318 			}
319 		}
320   	}
321 	info.slptimeo = slptimeo;
322 	info.lkflags = LK_EXCLUSIVE | LK_SLEEPFAIL;
323 	if (slpflag & PCATCH)
324 		info.lkflags |= LK_PCATCH;
325 	info.flags = flags;
326 	info.vp = vp;
327 
328 	/*
329 	 * Flush the buffer cache until nothing is left.
330 	 */
331 	while (!RB_EMPTY(&vp->v_rbclean_tree) ||
332 	       !RB_EMPTY(&vp->v_rbdirty_tree)) {
333 		info.clean = 1;
334 		error = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree, NULL,
335 				vinvalbuf_bp, &info);
336 		if (error == 0) {
337 			info.clean = 0;
338 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
339 					vinvalbuf_bp, &info);
340 		}
341 	}
342 
343 	/*
344 	 * Wait for I/O completion.  We may block in the pip code so we have
345 	 * to re-check.
346 	 */
347 	do {
348 		bio_track_wait(&vp->v_track_write, 0, 0);
349 		if ((object = vp->v_object) != NULL) {
350 			refcount_wait(&object->paging_in_progress, "vnvlbx");
351 		}
352 	} while (bio_track_active(&vp->v_track_write));
353 
354 	/*
355 	 * Destroy the copy in the VM cache, too.
356 	 */
357 	if ((object = vp->v_object) != NULL) {
358 		vm_object_page_remove(object, 0, 0,
359 			(flags & V_SAVE) ? TRUE : FALSE);
360 	}
361 
362 	if (!RB_EMPTY(&vp->v_rbdirty_tree) || !RB_EMPTY(&vp->v_rbclean_tree))
363 		panic("vinvalbuf: flush failed");
364 	if (!RB_EMPTY(&vp->v_rbhash_tree))
365 		panic("vinvalbuf: flush failed, buffers still present");
366 	error = 0;
367 done:
368 	lwkt_reltoken(&vp->v_token);
369 	return (error);
370 }
371 
372 static int
373 vinvalbuf_bp(struct buf *bp, void *data)
374 {
375 	struct vinvalbuf_bp_info *info = data;
376 	int error;
377 
378 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
379 		atomic_add_int(&bp->b_refs, 1);
380 		error = BUF_TIMELOCK(bp, info->lkflags,
381 				     "vinvalbuf", info->slptimeo);
382 		atomic_subtract_int(&bp->b_refs, 1);
383 		if (error == 0) {
384 			BUF_UNLOCK(bp);
385 			error = ENOLCK;
386 		}
387 		if (error == ENOLCK)
388 			return(0);
389 		return (-error);
390 	}
391 	KKASSERT(bp->b_vp == info->vp);
392 
393 	/*
394 	 * Must check clean/dirty status after successfully locking as
395 	 * it may race.
396 	 */
397 	if ((info->clean && (bp->b_flags & B_DELWRI)) ||
398 	    (info->clean == 0 && (bp->b_flags & B_DELWRI) == 0)) {
399 		BUF_UNLOCK(bp);
400 		return(0);
401 	}
402 
403 	/*
404 	 * NOTE:  NO B_LOCKED CHECK.  Also no buf_checkwrite()
405 	 * check.  This code will write out the buffer, period.
406 	 */
407 	bremfree(bp);
408 	if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
409 	    (info->flags & V_SAVE)) {
410 		cluster_awrite(bp);
411 	} else if (info->flags & V_SAVE) {
412 		/*
413 		 * Cannot set B_NOCACHE on a clean buffer as this will
414 		 * destroy the VM backing store which might actually
415 		 * be dirty (and unsynchronized).
416 		 */
417 		bp->b_flags |= (B_INVAL | B_RELBUF);
418 		brelse(bp);
419 	} else {
420 		bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
421 		brelse(bp);
422 	}
423 	return(0);
424 }
425 
426 /*
427  * Truncate a file's buffer and pages to a specified length.  This
428  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
429  * sync activity.
430  *
431  * The vnode must be locked.
432  */
433 static int vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data);
434 static int vtruncbuf_bp_trunc(struct buf *bp, void *data);
435 static int vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data);
436 static int vtruncbuf_bp_metasync(struct buf *bp, void *data);
437 
438 struct vtruncbuf_info {
439 	struct vnode *vp;
440 	off_t	truncloffset;
441 	int	clean;
442 };
443 
444 int
445 vtruncbuf(struct vnode *vp, off_t length, int blksize)
446 {
447 	struct vtruncbuf_info info;
448 	const char *filename;
449 	int count;
450 
451 	/*
452 	 * Round up to the *next* block, then destroy the buffers in question.
453 	 * Since we are only removing some of the buffers we must rely on the
454 	 * scan count to determine whether a loop is necessary.
455 	 */
456 	if ((count = (int)(length % blksize)) != 0)
457 		info.truncloffset = length + (blksize - count);
458 	else
459 		info.truncloffset = length;
460 	info.vp = vp;
461 
462 	lwkt_gettoken(&vp->v_token);
463 	do {
464 		info.clean = 1;
465 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
466 				vtruncbuf_bp_trunc_cmp,
467 				vtruncbuf_bp_trunc, &info);
468 		info.clean = 0;
469 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
470 				vtruncbuf_bp_trunc_cmp,
471 				vtruncbuf_bp_trunc, &info);
472 	} while(count);
473 
474 	/*
475 	 * For safety, fsync any remaining metadata if the file is not being
476 	 * truncated to 0.  Since the metadata does not represent the entire
477 	 * dirty list we have to rely on the hit count to ensure that we get
478 	 * all of it.
479 	 */
480 	if (length > 0) {
481 		do {
482 			count = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
483 					vtruncbuf_bp_metasync_cmp,
484 					vtruncbuf_bp_metasync, &info);
485 		} while (count);
486 	}
487 
488 	/*
489 	 * Clean out any left over VM backing store.
490 	 *
491 	 * It is possible to have in-progress I/O from buffers that were
492 	 * not part of the truncation.  This should not happen if we
493 	 * are truncating to 0-length.
494 	 */
495 	vnode_pager_setsize(vp, length);
496 	bio_track_wait(&vp->v_track_write, 0, 0);
497 
498 	/*
499 	 * Debugging only
500 	 */
501 	spin_lock(&vp->v_spin);
502 	filename = TAILQ_FIRST(&vp->v_namecache) ?
503 		   TAILQ_FIRST(&vp->v_namecache)->nc_name : "?";
504 	spin_unlock(&vp->v_spin);
505 
506 	/*
507 	 * Make sure no buffers were instantiated while we were trying
508 	 * to clean out the remaining VM pages.  This could occur due
509 	 * to busy dirty VM pages being flushed out to disk.
510 	 */
511 	do {
512 		info.clean = 1;
513 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
514 				vtruncbuf_bp_trunc_cmp,
515 				vtruncbuf_bp_trunc, &info);
516 		info.clean = 0;
517 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
518 				vtruncbuf_bp_trunc_cmp,
519 				vtruncbuf_bp_trunc, &info);
520 		if (count) {
521 			kprintf("Warning: vtruncbuf():  Had to re-clean %d "
522 			       "left over buffers in %s\n", count, filename);
523 		}
524 	} while(count);
525 
526 	lwkt_reltoken(&vp->v_token);
527 
528 	return (0);
529 }
530 
531 /*
532  * The callback buffer is beyond the new file EOF and must be destroyed.
533  * Note that the compare function must conform to the RB_SCAN's requirements.
534  */
535 static
536 int
537 vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data)
538 {
539 	struct vtruncbuf_info *info = data;
540 
541 	if (bp->b_loffset >= info->truncloffset)
542 		return(0);
543 	return(-1);
544 }
545 
546 static
547 int
548 vtruncbuf_bp_trunc(struct buf *bp, void *data)
549 {
550 	struct vtruncbuf_info *info = data;
551 
552 	/*
553 	 * Do not try to use a buffer we cannot immediately lock, but sleep
554 	 * anyway to prevent a livelock.  The code will loop until all buffers
555 	 * can be acted upon.
556 	 *
557 	 * We must always revalidate the buffer after locking it to deal
558 	 * with MP races.
559 	 */
560 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
561 		atomic_add_int(&bp->b_refs, 1);
562 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
563 			BUF_UNLOCK(bp);
564 		atomic_subtract_int(&bp->b_refs, 1);
565 	} else if ((info->clean && (bp->b_flags & B_DELWRI)) ||
566 		   (info->clean == 0 && (bp->b_flags & B_DELWRI) == 0) ||
567 		   bp->b_vp != info->vp ||
568 		   vtruncbuf_bp_trunc_cmp(bp, data)) {
569 		BUF_UNLOCK(bp);
570 	} else {
571 		bremfree(bp);
572 		bp->b_flags |= (B_INVAL | B_RELBUF | B_NOCACHE);
573 		brelse(bp);
574 	}
575 	return(1);
576 }
577 
578 /*
579  * Fsync all meta-data after truncating a file to be non-zero.  Only metadata
580  * blocks (with a negative loffset) are scanned.
581  * Note that the compare function must conform to the RB_SCAN's requirements.
582  */
583 static int
584 vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data __unused)
585 {
586 	if (bp->b_loffset < 0)
587 		return(0);
588 	return(1);
589 }
590 
591 static int
592 vtruncbuf_bp_metasync(struct buf *bp, void *data)
593 {
594 	struct vtruncbuf_info *info = data;
595 
596 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
597 		atomic_add_int(&bp->b_refs, 1);
598 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
599 			BUF_UNLOCK(bp);
600 		atomic_subtract_int(&bp->b_refs, 1);
601 	} else if ((bp->b_flags & B_DELWRI) == 0 ||
602 		   bp->b_vp != info->vp ||
603 		   vtruncbuf_bp_metasync_cmp(bp, data)) {
604 		BUF_UNLOCK(bp);
605 	} else {
606 		bremfree(bp);
607 		if (bp->b_vp == info->vp)
608 			bawrite(bp);
609 		else
610 			bwrite(bp);
611 	}
612 	return(1);
613 }
614 
615 /*
616  * vfsync - implements a multipass fsync on a file which understands
617  * dependancies and meta-data.  The passed vnode must be locked.  The
618  * waitfor argument may be MNT_WAIT or MNT_NOWAIT, or MNT_LAZY.
619  *
620  * When fsyncing data asynchronously just do one consolidated pass starting
621  * with the most negative block number.  This may not get all the data due
622  * to dependancies.
623  *
624  * When fsyncing data synchronously do a data pass, then a metadata pass,
625  * then do additional data+metadata passes to try to get all the data out.
626  */
627 static int vfsync_wait_output(struct vnode *vp,
628 			    int (*waitoutput)(struct vnode *, struct thread *));
629 static int vfsync_dummy_cmp(struct buf *bp __unused, void *data __unused);
630 static int vfsync_data_only_cmp(struct buf *bp, void *data);
631 static int vfsync_meta_only_cmp(struct buf *bp, void *data);
632 static int vfsync_lazy_range_cmp(struct buf *bp, void *data);
633 static int vfsync_bp(struct buf *bp, void *data);
634 
635 struct vfsync_info {
636 	struct vnode *vp;
637 	int synchronous;
638 	int syncdeps;
639 	int lazycount;
640 	int lazylimit;
641 	int skippedbufs;
642 	int (*checkdef)(struct buf *);
643 	int (*cmpfunc)(struct buf *, void *);
644 };
645 
646 int
647 vfsync(struct vnode *vp, int waitfor, int passes,
648 	int (*checkdef)(struct buf *),
649 	int (*waitoutput)(struct vnode *, struct thread *))
650 {
651 	struct vfsync_info info;
652 	int error;
653 
654 	bzero(&info, sizeof(info));
655 	info.vp = vp;
656 	if ((info.checkdef = checkdef) == NULL)
657 		info.syncdeps = 1;
658 
659 	lwkt_gettoken(&vp->v_token);
660 
661 	switch(waitfor) {
662 	case MNT_LAZY | MNT_NOWAIT:
663 	case MNT_LAZY:
664 		/*
665 		 * Lazy (filesystem syncer typ) Asynchronous plus limit the
666 		 * number of data (not meta) pages we try to flush to 1MB.
667 		 * A non-zero return means that lazy limit was reached.
668 		 */
669 		info.lazylimit = 1024 * 1024;
670 		info.syncdeps = 1;
671 		info.cmpfunc = vfsync_lazy_range_cmp;
672 		error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
673 				vfsync_lazy_range_cmp, vfsync_bp, &info);
674 		info.cmpfunc = vfsync_meta_only_cmp;
675 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
676 			vfsync_meta_only_cmp, vfsync_bp, &info);
677 		if (error == 0)
678 			vp->v_lazyw = 0;
679 		else if (!RB_EMPTY(&vp->v_rbdirty_tree))
680 			vn_syncer_add(vp, 1);
681 		error = 0;
682 		break;
683 	case MNT_NOWAIT:
684 		/*
685 		 * Asynchronous.  Do a data-only pass and a meta-only pass.
686 		 */
687 		info.syncdeps = 1;
688 		info.cmpfunc = vfsync_data_only_cmp;
689 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
690 			vfsync_bp, &info);
691 		info.cmpfunc = vfsync_meta_only_cmp;
692 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_meta_only_cmp,
693 			vfsync_bp, &info);
694 		error = 0;
695 		break;
696 	default:
697 		/*
698 		 * Synchronous.  Do a data-only pass, then a meta-data+data
699 		 * pass, then additional integrated passes to try to get
700 		 * all the dependancies flushed.
701 		 */
702 		info.cmpfunc = vfsync_data_only_cmp;
703 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
704 			vfsync_bp, &info);
705 		error = vfsync_wait_output(vp, waitoutput);
706 		if (error == 0) {
707 			info.skippedbufs = 0;
708 			info.cmpfunc = vfsync_dummy_cmp;
709 			RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
710 				vfsync_bp, &info);
711 			error = vfsync_wait_output(vp, waitoutput);
712 			if (info.skippedbufs) {
713 				kprintf("Warning: vfsync skipped %d dirty "
714 					"bufs in pass2!\n", info.skippedbufs);
715 			}
716 		}
717 		while (error == 0 && passes > 0 &&
718 		       !RB_EMPTY(&vp->v_rbdirty_tree)
719 		) {
720 			if (--passes == 0) {
721 				info.synchronous = 1;
722 				info.syncdeps = 1;
723 			}
724 			info.cmpfunc = vfsync_dummy_cmp;
725 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
726 					vfsync_bp, &info);
727 			if (error < 0)
728 				error = -error;
729 			info.syncdeps = 1;
730 			if (error == 0)
731 				error = vfsync_wait_output(vp, waitoutput);
732 		}
733 		break;
734 	}
735 	lwkt_reltoken(&vp->v_token);
736 	return(error);
737 }
738 
739 static int
740 vfsync_wait_output(struct vnode *vp,
741 		   int (*waitoutput)(struct vnode *, struct thread *))
742 {
743 	int error;
744 
745 	error = bio_track_wait(&vp->v_track_write, 0, 0);
746 	if (waitoutput)
747 		error = waitoutput(vp, curthread);
748 	return(error);
749 }
750 
751 static int
752 vfsync_dummy_cmp(struct buf *bp __unused, void *data __unused)
753 {
754 	return(0);
755 }
756 
757 static int
758 vfsync_data_only_cmp(struct buf *bp, void *data)
759 {
760 	if (bp->b_loffset < 0)
761 		return(-1);
762 	return(0);
763 }
764 
765 static int
766 vfsync_meta_only_cmp(struct buf *bp, void *data)
767 {
768 	if (bp->b_loffset < 0)
769 		return(0);
770 	return(1);
771 }
772 
773 static int
774 vfsync_lazy_range_cmp(struct buf *bp, void *data)
775 {
776 	struct vfsync_info *info = data;
777 
778 	if (bp->b_loffset < info->vp->v_lazyw)
779 		return(-1);
780 	return(0);
781 }
782 
783 static int
784 vfsync_bp(struct buf *bp, void *data)
785 {
786 	struct vfsync_info *info = data;
787 	struct vnode *vp = info->vp;
788 	int error;
789 
790 	/*
791 	 * Ignore buffers that we cannot immediately lock.
792 	 */
793 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
794 		++info->skippedbufs;
795 		return(0);
796 	}
797 
798 	/*
799 	 * We must revalidate the buffer after locking.
800 	 */
801 	if ((bp->b_flags & B_DELWRI) == 0 ||
802 	    bp->b_vp != info->vp ||
803 	    info->cmpfunc(bp, data)) {
804 		BUF_UNLOCK(bp);
805 		return(0);
806 	}
807 
808 	/*
809 	 * If syncdeps is not set we do not try to write buffers which have
810 	 * dependancies.
811 	 */
812 	if (!info->synchronous && info->syncdeps == 0 && info->checkdef(bp)) {
813 		BUF_UNLOCK(bp);
814 		return(0);
815 	}
816 
817 	/*
818 	 * B_NEEDCOMMIT (primarily used by NFS) is a state where the buffer
819 	 * has been written but an additional handshake with the device
820 	 * is required before we can dispose of the buffer.  We have no idea
821 	 * how to do this so we have to skip these buffers.
822 	 */
823 	if (bp->b_flags & B_NEEDCOMMIT) {
824 		BUF_UNLOCK(bp);
825 		return(0);
826 	}
827 
828 	/*
829 	 * Ask bioops if it is ok to sync.  If not the VFS may have
830 	 * set B_LOCKED so we have to cycle the buffer.
831 	 */
832 	if (LIST_FIRST(&bp->b_dep) != NULL && buf_checkwrite(bp)) {
833 		bremfree(bp);
834 		brelse(bp);
835 		return(0);
836 	}
837 
838 	if (info->synchronous) {
839 		/*
840 		 * Synchronous flushing.  An error may be returned.
841 		 */
842 		bremfree(bp);
843 		error = bwrite(bp);
844 	} else {
845 		/*
846 		 * Asynchronous flushing.  A negative return value simply
847 		 * stops the scan and is not considered an error.  We use
848 		 * this to support limited MNT_LAZY flushes.
849 		 */
850 		vp->v_lazyw = bp->b_loffset;
851 		bremfree(bp);
852 		info->lazycount += cluster_awrite(bp);
853 		waitrunningbufspace();
854 		vm_wait_nominal();
855 		if (info->lazylimit && info->lazycount >= info->lazylimit)
856 			error = 1;
857 		else
858 			error = 0;
859 	}
860 	return(-error);
861 }
862 
863 /*
864  * Associate a buffer with a vnode.
865  *
866  * MPSAFE
867  */
868 int
869 bgetvp(struct vnode *vp, struct buf *bp, int testsize)
870 {
871 	KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));
872 	KKASSERT((bp->b_flags & (B_HASHED|B_DELWRI|B_VNCLEAN|B_VNDIRTY)) == 0);
873 
874 	/*
875 	 * Insert onto list for new vnode.
876 	 */
877 	lwkt_gettoken(&vp->v_token);
878 
879 	if (buf_rb_hash_RB_INSERT(&vp->v_rbhash_tree, bp)) {
880 		lwkt_reltoken(&vp->v_token);
881 		return (EEXIST);
882 	}
883 
884 	/*
885 	 * Diagnostics (mainly for HAMMER debugging).  Check for
886 	 * overlapping buffers.
887 	 */
888 	if (check_buf_overlap) {
889 		struct buf *bx;
890 		bx = buf_rb_hash_RB_PREV(bp);
891 		if (bx) {
892 			if (bx->b_loffset + bx->b_bufsize > bp->b_loffset) {
893 				kprintf("bgetvp: overlapl %016jx/%d %016jx "
894 					"bx %p bp %p\n",
895 					(intmax_t)bx->b_loffset,
896 					bx->b_bufsize,
897 					(intmax_t)bp->b_loffset,
898 					bx, bp);
899 				if (check_buf_overlap > 1)
900 					panic("bgetvp - overlapping buffer");
901 			}
902 		}
903 		bx = buf_rb_hash_RB_NEXT(bp);
904 		if (bx) {
905 			if (bp->b_loffset + testsize > bx->b_loffset) {
906 				kprintf("bgetvp: overlapr %016jx/%d %016jx "
907 					"bp %p bx %p\n",
908 					(intmax_t)bp->b_loffset,
909 					testsize,
910 					(intmax_t)bx->b_loffset,
911 					bp, bx);
912 				if (check_buf_overlap > 1)
913 					panic("bgetvp - overlapping buffer");
914 			}
915 		}
916 	}
917 	bp->b_vp = vp;
918 	bp->b_flags |= B_HASHED;
919 	bp->b_flags |= B_VNCLEAN;
920 	if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp))
921 		panic("reassignbuf: dup lblk/clean vp %p bp %p", vp, bp);
922 	vhold(vp);
923 	lwkt_reltoken(&vp->v_token);
924 	return(0);
925 }
926 
927 /*
928  * Disassociate a buffer from a vnode.
929  *
930  * MPSAFE
931  */
932 void
933 brelvp(struct buf *bp)
934 {
935 	struct vnode *vp;
936 
937 	KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
938 
939 	/*
940 	 * Delete from old vnode list, if on one.
941 	 */
942 	vp = bp->b_vp;
943 	lwkt_gettoken(&vp->v_token);
944 	if (bp->b_flags & (B_VNDIRTY | B_VNCLEAN)) {
945 		if (bp->b_flags & B_VNDIRTY)
946 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
947 		else
948 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
949 		bp->b_flags &= ~(B_VNDIRTY | B_VNCLEAN);
950 	}
951 	if (bp->b_flags & B_HASHED) {
952 		buf_rb_hash_RB_REMOVE(&vp->v_rbhash_tree, bp);
953 		bp->b_flags &= ~B_HASHED;
954 	}
955 	if ((vp->v_flag & VONWORKLST) && RB_EMPTY(&vp->v_rbdirty_tree))
956 		vn_syncer_remove(vp);
957 	bp->b_vp = NULL;
958 
959 	lwkt_reltoken(&vp->v_token);
960 
961 	vdrop(vp);
962 }
963 
964 /*
965  * Reassign the buffer to the proper clean/dirty list based on B_DELWRI.
966  * This routine is called when the state of the B_DELWRI bit is changed.
967  *
968  * Must be called with vp->v_token held.
969  * MPSAFE
970  */
971 void
972 reassignbuf(struct buf *bp)
973 {
974 	struct vnode *vp = bp->b_vp;
975 	int delay;
976 
977 	ASSERT_LWKT_TOKEN_HELD(&vp->v_token);
978 	++reassignbufcalls;
979 
980 	/*
981 	 * B_PAGING flagged buffers cannot be reassigned because their vp
982 	 * is not fully linked in.
983 	 */
984 	if (bp->b_flags & B_PAGING)
985 		panic("cannot reassign paging buffer");
986 
987 	if (bp->b_flags & B_DELWRI) {
988 		/*
989 		 * Move to the dirty list, add the vnode to the worklist
990 		 */
991 		if (bp->b_flags & B_VNCLEAN) {
992 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
993 			bp->b_flags &= ~B_VNCLEAN;
994 		}
995 		if ((bp->b_flags & B_VNDIRTY) == 0) {
996 			if (buf_rb_tree_RB_INSERT(&vp->v_rbdirty_tree, bp)) {
997 				panic("reassignbuf: dup lblk vp %p bp %p",
998 				      vp, bp);
999 			}
1000 			bp->b_flags |= B_VNDIRTY;
1001 		}
1002 		if ((vp->v_flag & VONWORKLST) == 0) {
1003 			switch (vp->v_type) {
1004 			case VDIR:
1005 				delay = dirdelay;
1006 				break;
1007 			case VCHR:
1008 			case VBLK:
1009 				if (vp->v_rdev &&
1010 				    vp->v_rdev->si_mountpoint != NULL) {
1011 					delay = metadelay;
1012 					break;
1013 				}
1014 				/* fall through */
1015 			default:
1016 				delay = filedelay;
1017 			}
1018 			vn_syncer_add(vp, delay);
1019 		}
1020 	} else {
1021 		/*
1022 		 * Move to the clean list, remove the vnode from the worklist
1023 		 * if no dirty blocks remain.
1024 		 */
1025 		if (bp->b_flags & B_VNDIRTY) {
1026 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
1027 			bp->b_flags &= ~B_VNDIRTY;
1028 		}
1029 		if ((bp->b_flags & B_VNCLEAN) == 0) {
1030 			if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp)) {
1031 				panic("reassignbuf: dup lblk vp %p bp %p",
1032 				      vp, bp);
1033 			}
1034 			bp->b_flags |= B_VNCLEAN;
1035 		}
1036 		if ((vp->v_flag & VONWORKLST) &&
1037 		    RB_EMPTY(&vp->v_rbdirty_tree)) {
1038 			vn_syncer_remove(vp);
1039 		}
1040 	}
1041 }
1042 
1043 /*
1044  * Create a vnode for a block device.  Used for mounting the root file
1045  * system.
1046  *
1047  * A vref()'d vnode is returned.
1048  */
1049 extern struct vop_ops *devfs_vnode_dev_vops_p;
1050 int
1051 bdevvp(cdev_t dev, struct vnode **vpp)
1052 {
1053 	struct vnode *vp;
1054 	struct vnode *nvp;
1055 	int error;
1056 
1057 	if (dev == NULL) {
1058 		*vpp = NULLVP;
1059 		return (ENXIO);
1060 	}
1061 	error = getspecialvnode(VT_NON, NULL, &devfs_vnode_dev_vops_p,
1062 				&nvp, 0, 0);
1063 	if (error) {
1064 		*vpp = NULLVP;
1065 		return (error);
1066 	}
1067 	vp = nvp;
1068 	vp->v_type = VCHR;
1069 #if 0
1070 	vp->v_rdev = dev;
1071 #endif
1072 	v_associate_rdev(vp, dev);
1073 	vp->v_umajor = dev->si_umajor;
1074 	vp->v_uminor = dev->si_uminor;
1075 	vx_unlock(vp);
1076 	*vpp = vp;
1077 	return (0);
1078 }
1079 
1080 int
1081 v_associate_rdev(struct vnode *vp, cdev_t dev)
1082 {
1083 	if (dev == NULL)
1084 		return(ENXIO);
1085 	if (dev_is_good(dev) == 0)
1086 		return(ENXIO);
1087 	KKASSERT(vp->v_rdev == NULL);
1088 	vp->v_rdev = reference_dev(dev);
1089 	lwkt_gettoken(&spechash_token);
1090 	SLIST_INSERT_HEAD(&dev->si_hlist, vp, v_cdevnext);
1091 	lwkt_reltoken(&spechash_token);
1092 	return(0);
1093 }
1094 
1095 void
1096 v_release_rdev(struct vnode *vp)
1097 {
1098 	cdev_t dev;
1099 
1100 	if ((dev = vp->v_rdev) != NULL) {
1101 		lwkt_gettoken(&spechash_token);
1102 		SLIST_REMOVE(&dev->si_hlist, vp, vnode, v_cdevnext);
1103 		vp->v_rdev = NULL;
1104 		release_dev(dev);
1105 		lwkt_reltoken(&spechash_token);
1106 	}
1107 }
1108 
1109 /*
1110  * Add a vnode to the alias list hung off the cdev_t.  We only associate
1111  * the device number with the vnode.  The actual device is not associated
1112  * until the vnode is opened (usually in spec_open()), and will be
1113  * disassociated on last close.
1114  */
1115 void
1116 addaliasu(struct vnode *nvp, int x, int y)
1117 {
1118 	if (nvp->v_type != VBLK && nvp->v_type != VCHR)
1119 		panic("addaliasu on non-special vnode");
1120 	nvp->v_umajor = x;
1121 	nvp->v_uminor = y;
1122 }
1123 
1124 /*
1125  * Simple call that a filesystem can make to try to get rid of a
1126  * vnode.  It will fail if anyone is referencing the vnode (including
1127  * the caller).
1128  *
1129  * The filesystem can check whether its in-memory inode structure still
1130  * references the vp on return.
1131  */
1132 void
1133 vclean_unlocked(struct vnode *vp)
1134 {
1135 	vx_get(vp);
1136 	if (sysref_isactive(&vp->v_sysref) == 0)
1137 		vgone_vxlocked(vp);
1138 	vx_put(vp);
1139 }
1140 
1141 /*
1142  * Disassociate a vnode from its underlying filesystem.
1143  *
1144  * The vnode must be VX locked and referenced.  In all normal situations
1145  * there are no active references.  If vclean_vxlocked() is called while
1146  * there are active references, the vnode is being ripped out and we have
1147  * to call VOP_CLOSE() as appropriate before we can reclaim it.
1148  */
1149 void
1150 vclean_vxlocked(struct vnode *vp, int flags)
1151 {
1152 	int active;
1153 	int n;
1154 	vm_object_t object;
1155 	struct namecache *ncp;
1156 
1157 	/*
1158 	 * If the vnode has already been reclaimed we have nothing to do.
1159 	 */
1160 	if (vp->v_flag & VRECLAIMED)
1161 		return;
1162 	vsetflags(vp, VRECLAIMED);
1163 
1164 	if (verbose_reclaims) {
1165 		if ((ncp = TAILQ_FIRST(&vp->v_namecache)) != NULL)
1166 			kprintf("Debug: reclaim %p %s\n", vp, ncp->nc_name);
1167 	}
1168 
1169 	/*
1170 	 * Scrap the vfs cache
1171 	 */
1172 	while (cache_inval_vp(vp, 0) != 0) {
1173 		kprintf("Warning: vnode %p clean/cache_resolution "
1174 			"race detected\n", vp);
1175 		tsleep(vp, 0, "vclninv", 2);
1176 	}
1177 
1178 	/*
1179 	 * Check to see if the vnode is in use. If so we have to reference it
1180 	 * before we clean it out so that its count cannot fall to zero and
1181 	 * generate a race against ourselves to recycle it.
1182 	 */
1183 	active = sysref_isactive(&vp->v_sysref);
1184 
1185 	/*
1186 	 * Clean out any buffers associated with the vnode and destroy its
1187 	 * object, if it has one.
1188 	 */
1189 	vinvalbuf(vp, V_SAVE, 0, 0);
1190 
1191 	/*
1192 	 * If purging an active vnode (typically during a forced unmount
1193 	 * or reboot), it must be closed and deactivated before being
1194 	 * reclaimed.  This isn't really all that safe, but what can
1195 	 * we do? XXX.
1196 	 *
1197 	 * Note that neither of these routines unlocks the vnode.
1198 	 */
1199 	if (active && (flags & DOCLOSE)) {
1200 		while ((n = vp->v_opencount) != 0) {
1201 			if (vp->v_writecount)
1202 				VOP_CLOSE(vp, FWRITE|FNONBLOCK);
1203 			else
1204 				VOP_CLOSE(vp, FNONBLOCK);
1205 			if (vp->v_opencount == n) {
1206 				kprintf("Warning: unable to force-close"
1207 				       " vnode %p\n", vp);
1208 				break;
1209 			}
1210 		}
1211 	}
1212 
1213 	/*
1214 	 * If the vnode has not been deactivated, deactivated it.  Deactivation
1215 	 * can create new buffers and VM pages so we have to call vinvalbuf()
1216 	 * again to make sure they all get flushed.
1217 	 *
1218 	 * This can occur if a file with a link count of 0 needs to be
1219 	 * truncated.
1220 	 *
1221 	 * If the vnode is already dead don't try to deactivate it.
1222 	 */
1223 	if ((vp->v_flag & VINACTIVE) == 0) {
1224 		vsetflags(vp, VINACTIVE);
1225 		if (vp->v_mount)
1226 			VOP_INACTIVE(vp);
1227 		vinvalbuf(vp, V_SAVE, 0, 0);
1228 	}
1229 
1230 	/*
1231 	 * If the vnode has an object, destroy it.
1232 	 */
1233 	while ((object = vp->v_object) != NULL) {
1234 		vm_object_hold(object);
1235 		if (object == vp->v_object)
1236 			break;
1237 		vm_object_drop(object);
1238 	}
1239 
1240 	if (object != NULL) {
1241 		if (object->ref_count == 0) {
1242 			if ((object->flags & OBJ_DEAD) == 0)
1243 				vm_object_terminate(object);
1244 			vm_object_drop(object);
1245 			vclrflags(vp, VOBJBUF);
1246 		} else {
1247 			vm_pager_deallocate(object);
1248 			vclrflags(vp, VOBJBUF);
1249 			vm_object_drop(object);
1250 		}
1251 	}
1252 	KKASSERT((vp->v_flag & VOBJBUF) == 0);
1253 
1254 	/*
1255 	 * Reclaim the vnode if not already dead.
1256 	 */
1257 	if (vp->v_mount && VOP_RECLAIM(vp))
1258 		panic("vclean: cannot reclaim");
1259 
1260 	/*
1261 	 * Done with purge, notify sleepers of the grim news.
1262 	 */
1263 	vp->v_ops = &dead_vnode_vops_p;
1264 	vn_gone(vp);
1265 	vp->v_tag = VT_NON;
1266 
1267 	/*
1268 	 * If we are destroying an active vnode, reactivate it now that
1269 	 * we have reassociated it with deadfs.  This prevents the system
1270 	 * from crashing on the vnode due to it being unexpectedly marked
1271 	 * as inactive or reclaimed.
1272 	 */
1273 	if (active && (flags & DOCLOSE)) {
1274 		vclrflags(vp, VINACTIVE | VRECLAIMED);
1275 	}
1276 }
1277 
1278 /*
1279  * Eliminate all activity associated with the requested vnode
1280  * and with all vnodes aliased to the requested vnode.
1281  *
1282  * The vnode must be referenced but should not be locked.
1283  */
1284 int
1285 vrevoke(struct vnode *vp, struct ucred *cred)
1286 {
1287 	struct vnode *vq;
1288 	struct vnode *vqn;
1289 	cdev_t dev;
1290 	int error;
1291 
1292 	/*
1293 	 * If the vnode has a device association, scrap all vnodes associated
1294 	 * with the device.  Don't let the device disappear on us while we
1295 	 * are scrapping the vnodes.
1296 	 *
1297 	 * The passed vp will probably show up in the list, do not VX lock
1298 	 * it twice!
1299 	 *
1300 	 * Releasing the vnode's rdev here can mess up specfs's call to
1301 	 * device close, so don't do it.  The vnode has been disassociated
1302 	 * and the device will be closed after the last ref on the related
1303 	 * fp goes away (if not still open by e.g. the kernel).
1304 	 */
1305 	if (vp->v_type != VCHR) {
1306 		error = fdrevoke(vp, DTYPE_VNODE, cred);
1307 		return (error);
1308 	}
1309 	if ((dev = vp->v_rdev) == NULL) {
1310 		return(0);
1311 	}
1312 	reference_dev(dev);
1313 	lwkt_gettoken(&spechash_token);
1314 
1315 restart:
1316 	vqn = SLIST_FIRST(&dev->si_hlist);
1317 	if (vqn)
1318 		vhold(vqn);
1319 	while ((vq = vqn) != NULL) {
1320 		if (sysref_isactive(&vq->v_sysref)) {
1321 			vref(vq);
1322 			fdrevoke(vq, DTYPE_VNODE, cred);
1323 			/*v_release_rdev(vq);*/
1324 			vrele(vq);
1325 			if (vq->v_rdev != dev) {
1326 				vdrop(vq);
1327 				goto restart;
1328 			}
1329 		}
1330 		vqn = SLIST_NEXT(vq, v_cdevnext);
1331 		if (vqn)
1332 			vhold(vqn);
1333 		vdrop(vq);
1334 	}
1335 	lwkt_reltoken(&spechash_token);
1336 	dev_drevoke(dev);
1337 	release_dev(dev);
1338 	return (0);
1339 }
1340 
1341 /*
1342  * This is called when the object underlying a vnode is being destroyed,
1343  * such as in a remove().  Try to recycle the vnode immediately if the
1344  * only active reference is our reference.
1345  *
1346  * Directory vnodes in the namecache with children cannot be immediately
1347  * recycled because numerous VOP_N*() ops require them to be stable.
1348  *
1349  * To avoid recursive recycling from VOP_INACTIVE implemenetations this
1350  * function is a NOP if VRECLAIMED is already set.
1351  */
1352 int
1353 vrecycle(struct vnode *vp)
1354 {
1355 	if (vp->v_sysref.refcnt <= 1 && (vp->v_flag & VRECLAIMED) == 0) {
1356 		if (cache_inval_vp_nonblock(vp))
1357 			return(0);
1358 		vgone_vxlocked(vp);
1359 		return (1);
1360 	}
1361 	return (0);
1362 }
1363 
1364 /*
1365  * Return the maximum I/O size allowed for strategy calls on VP.
1366  *
1367  * If vp is VCHR or VBLK we dive the device, otherwise we use
1368  * the vp's mount info.
1369  *
1370  * The returned value is clamped at MAXPHYS as most callers cannot use
1371  * buffers larger than that size.
1372  */
1373 int
1374 vmaxiosize(struct vnode *vp)
1375 {
1376 	int maxiosize;
1377 
1378 	if (vp->v_type == VBLK || vp->v_type == VCHR)
1379 		maxiosize = vp->v_rdev->si_iosize_max;
1380 	else
1381 		maxiosize = vp->v_mount->mnt_iosize_max;
1382 
1383 	if (maxiosize > MAXPHYS)
1384 		maxiosize = MAXPHYS;
1385 	return (maxiosize);
1386 }
1387 
1388 /*
1389  * Eliminate all activity associated with a vnode in preparation for reuse.
1390  *
1391  * The vnode must be VX locked and refd and will remain VX locked and refd
1392  * on return.  This routine may be called with the vnode in any state, as
1393  * long as it is VX locked.  The vnode will be cleaned out and marked
1394  * VRECLAIMED but will not actually be reused until all existing refs and
1395  * holds go away.
1396  *
1397  * NOTE: This routine may be called on a vnode which has not yet been
1398  * already been deactivated (VOP_INACTIVE), or on a vnode which has
1399  * already been reclaimed.
1400  *
1401  * This routine is not responsible for placing us back on the freelist.
1402  * Instead, it happens automatically when the caller releases the VX lock
1403  * (assuming there aren't any other references).
1404  */
1405 void
1406 vgone_vxlocked(struct vnode *vp)
1407 {
1408 	/*
1409 	 * assert that the VX lock is held.  This is an absolute requirement
1410 	 * now for vgone_vxlocked() to be called.
1411 	 */
1412 	KKASSERT(vp->v_lock.lk_exclusivecount == 1);
1413 
1414 	/*
1415 	 * Clean out the filesystem specific data and set the VRECLAIMED
1416 	 * bit.  Also deactivate the vnode if necessary.
1417 	 */
1418 	vclean_vxlocked(vp, DOCLOSE);
1419 
1420 	/*
1421 	 * Delete from old mount point vnode list, if on one.
1422 	 */
1423 	if (vp->v_mount != NULL) {
1424 		KKASSERT(vp->v_data == NULL);
1425 		insmntque(vp, NULL);
1426 	}
1427 
1428 	/*
1429 	 * If special device, remove it from special device alias list
1430 	 * if it is on one.  This should normally only occur if a vnode is
1431 	 * being revoked as the device should otherwise have been released
1432 	 * naturally.
1433 	 */
1434 	if ((vp->v_type == VBLK || vp->v_type == VCHR) && vp->v_rdev != NULL) {
1435 		v_release_rdev(vp);
1436 	}
1437 
1438 	/*
1439 	 * Set us to VBAD
1440 	 */
1441 	vp->v_type = VBAD;
1442 }
1443 
1444 /*
1445  * Lookup a vnode by device number.
1446  *
1447  * Returns non-zero and *vpp set to a vref'd vnode on success.
1448  * Returns zero on failure.
1449  */
1450 int
1451 vfinddev(cdev_t dev, enum vtype type, struct vnode **vpp)
1452 {
1453 	struct vnode *vp;
1454 
1455 	lwkt_gettoken(&spechash_token);
1456 	SLIST_FOREACH(vp, &dev->si_hlist, v_cdevnext) {
1457 		if (type == vp->v_type) {
1458 			*vpp = vp;
1459 			vref(vp);
1460 			lwkt_reltoken(&spechash_token);
1461 			return (1);
1462 		}
1463 	}
1464 	lwkt_reltoken(&spechash_token);
1465 	return (0);
1466 }
1467 
1468 /*
1469  * Calculate the total number of references to a special device.  This
1470  * routine may only be called for VBLK and VCHR vnodes since v_rdev is
1471  * an overloaded field.  Since udev2dev can now return NULL, we have
1472  * to check for a NULL v_rdev.
1473  */
1474 int
1475 count_dev(cdev_t dev)
1476 {
1477 	struct vnode *vp;
1478 	int count = 0;
1479 
1480 	if (SLIST_FIRST(&dev->si_hlist)) {
1481 		lwkt_gettoken(&spechash_token);
1482 		SLIST_FOREACH(vp, &dev->si_hlist, v_cdevnext) {
1483 			count += vp->v_opencount;
1484 		}
1485 		lwkt_reltoken(&spechash_token);
1486 	}
1487 	return(count);
1488 }
1489 
1490 int
1491 vcount(struct vnode *vp)
1492 {
1493 	if (vp->v_rdev == NULL)
1494 		return(0);
1495 	return(count_dev(vp->v_rdev));
1496 }
1497 
1498 /*
1499  * Initialize VMIO for a vnode.  This routine MUST be called before a
1500  * VFS can issue buffer cache ops on a vnode.  It is typically called
1501  * when a vnode is initialized from its inode.
1502  */
1503 int
1504 vinitvmio(struct vnode *vp, off_t filesize, int blksize, int boff)
1505 {
1506 	vm_object_t object;
1507 	int error = 0;
1508 
1509 retry:
1510 	while ((object = vp->v_object) != NULL) {
1511 		vm_object_hold(object);
1512 		if (object == vp->v_object)
1513 			break;
1514 		vm_object_drop(object);
1515 	}
1516 
1517 	if (object == NULL) {
1518 		object = vnode_pager_alloc(vp, filesize, 0, 0, blksize, boff);
1519 
1520 		/*
1521 		 * Dereference the reference we just created.  This assumes
1522 		 * that the object is associated with the vp.
1523 		 */
1524 		vm_object_hold(object);
1525 		object->ref_count--;
1526 		vrele(vp);
1527 	} else {
1528 		if (object->flags & OBJ_DEAD) {
1529 			vn_unlock(vp);
1530 			if (vp->v_object == object)
1531 				vm_object_dead_sleep(object, "vodead");
1532 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1533 			vm_object_drop(object);
1534 			goto retry;
1535 		}
1536 	}
1537 	KASSERT(vp->v_object != NULL, ("vinitvmio: NULL object"));
1538 	vsetflags(vp, VOBJBUF);
1539 	vm_object_drop(object);
1540 
1541 	return (error);
1542 }
1543 
1544 
1545 /*
1546  * Print out a description of a vnode.
1547  */
1548 static char *typename[] =
1549 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
1550 
1551 void
1552 vprint(char *label, struct vnode *vp)
1553 {
1554 	char buf[96];
1555 
1556 	if (label != NULL)
1557 		kprintf("%s: %p: ", label, (void *)vp);
1558 	else
1559 		kprintf("%p: ", (void *)vp);
1560 	kprintf("type %s, sysrefs %d, writecount %d, holdcnt %d,",
1561 		typename[vp->v_type],
1562 		vp->v_sysref.refcnt, vp->v_writecount, vp->v_auxrefs);
1563 	buf[0] = '\0';
1564 	if (vp->v_flag & VROOT)
1565 		strcat(buf, "|VROOT");
1566 	if (vp->v_flag & VPFSROOT)
1567 		strcat(buf, "|VPFSROOT");
1568 	if (vp->v_flag & VTEXT)
1569 		strcat(buf, "|VTEXT");
1570 	if (vp->v_flag & VSYSTEM)
1571 		strcat(buf, "|VSYSTEM");
1572 	if (vp->v_flag & VFREE)
1573 		strcat(buf, "|VFREE");
1574 	if (vp->v_flag & VOBJBUF)
1575 		strcat(buf, "|VOBJBUF");
1576 	if (buf[0] != '\0')
1577 		kprintf(" flags (%s)", &buf[1]);
1578 	if (vp->v_data == NULL) {
1579 		kprintf("\n");
1580 	} else {
1581 		kprintf("\n\t");
1582 		VOP_PRINT(vp);
1583 	}
1584 }
1585 
1586 /*
1587  * Do the usual access checking.
1588  * file_mode, uid and gid are from the vnode in question,
1589  * while acc_mode and cred are from the VOP_ACCESS parameter list
1590  */
1591 int
1592 vaccess(enum vtype type, mode_t file_mode, uid_t uid, gid_t gid,
1593     mode_t acc_mode, struct ucred *cred)
1594 {
1595 	mode_t mask;
1596 	int ismember;
1597 
1598 	/*
1599 	 * Super-user always gets read/write access, but execute access depends
1600 	 * on at least one execute bit being set.
1601 	 */
1602 	if (priv_check_cred(cred, PRIV_ROOT, 0) == 0) {
1603 		if ((acc_mode & VEXEC) && type != VDIR &&
1604 		    (file_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)
1605 			return (EACCES);
1606 		return (0);
1607 	}
1608 
1609 	mask = 0;
1610 
1611 	/* Otherwise, check the owner. */
1612 	if (cred->cr_uid == uid) {
1613 		if (acc_mode & VEXEC)
1614 			mask |= S_IXUSR;
1615 		if (acc_mode & VREAD)
1616 			mask |= S_IRUSR;
1617 		if (acc_mode & VWRITE)
1618 			mask |= S_IWUSR;
1619 		return ((file_mode & mask) == mask ? 0 : EACCES);
1620 	}
1621 
1622 	/* Otherwise, check the groups. */
1623 	ismember = groupmember(gid, cred);
1624 	if (cred->cr_svgid == gid || ismember) {
1625 		if (acc_mode & VEXEC)
1626 			mask |= S_IXGRP;
1627 		if (acc_mode & VREAD)
1628 			mask |= S_IRGRP;
1629 		if (acc_mode & VWRITE)
1630 			mask |= S_IWGRP;
1631 		return ((file_mode & mask) == mask ? 0 : EACCES);
1632 	}
1633 
1634 	/* Otherwise, check everyone else. */
1635 	if (acc_mode & VEXEC)
1636 		mask |= S_IXOTH;
1637 	if (acc_mode & VREAD)
1638 		mask |= S_IROTH;
1639 	if (acc_mode & VWRITE)
1640 		mask |= S_IWOTH;
1641 	return ((file_mode & mask) == mask ? 0 : EACCES);
1642 }
1643 
1644 #ifdef DDB
1645 #include <ddb/ddb.h>
1646 
1647 static int db_show_locked_vnodes(struct mount *mp, void *data);
1648 
1649 /*
1650  * List all of the locked vnodes in the system.
1651  * Called when debugging the kernel.
1652  */
1653 DB_SHOW_COMMAND(lockedvnodes, lockedvnodes)
1654 {
1655 	kprintf("Locked vnodes\n");
1656 	mountlist_scan(db_show_locked_vnodes, NULL,
1657 			MNTSCAN_FORWARD|MNTSCAN_NOBUSY);
1658 }
1659 
1660 static int
1661 db_show_locked_vnodes(struct mount *mp, void *data __unused)
1662 {
1663 	struct vnode *vp;
1664 
1665 	TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
1666 		if (vn_islocked(vp))
1667 			vprint(NULL, vp);
1668 	}
1669 	return(0);
1670 }
1671 #endif
1672 
1673 /*
1674  * Top level filesystem related information gathering.
1675  */
1676 static int	sysctl_ovfs_conf (SYSCTL_HANDLER_ARGS);
1677 
1678 static int
1679 vfs_sysctl(SYSCTL_HANDLER_ARGS)
1680 {
1681 	int *name = (int *)arg1 - 1;	/* XXX */
1682 	u_int namelen = arg2 + 1;	/* XXX */
1683 	struct vfsconf *vfsp;
1684 	int maxtypenum;
1685 
1686 #if 1 || defined(COMPAT_PRELITE2)
1687 	/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
1688 	if (namelen == 1)
1689 		return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
1690 #endif
1691 
1692 #ifdef notyet
1693 	/* all sysctl names at this level are at least name and field */
1694 	if (namelen < 2)
1695 		return (ENOTDIR);		/* overloaded */
1696 	if (name[0] != VFS_GENERIC) {
1697 		vfsp = vfsconf_find_by_typenum(name[0]);
1698 		if (vfsp == NULL)
1699 			return (EOPNOTSUPP);
1700 		return ((*vfsp->vfc_vfsops->vfs_sysctl)(&name[1], namelen - 1,
1701 		    oldp, oldlenp, newp, newlen, p));
1702 	}
1703 #endif
1704 	switch (name[1]) {
1705 	case VFS_MAXTYPENUM:
1706 		if (namelen != 2)
1707 			return (ENOTDIR);
1708 		maxtypenum = vfsconf_get_maxtypenum();
1709 		return (SYSCTL_OUT(req, &maxtypenum, sizeof(maxtypenum)));
1710 	case VFS_CONF:
1711 		if (namelen != 3)
1712 			return (ENOTDIR);	/* overloaded */
1713 		vfsp = vfsconf_find_by_typenum(name[2]);
1714 		if (vfsp == NULL)
1715 			return (EOPNOTSUPP);
1716 		return (SYSCTL_OUT(req, vfsp, sizeof *vfsp));
1717 	}
1718 	return (EOPNOTSUPP);
1719 }
1720 
1721 SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD, vfs_sysctl,
1722 	"Generic filesystem");
1723 
1724 #if 1 || defined(COMPAT_PRELITE2)
1725 
1726 static int
1727 sysctl_ovfs_conf_iter(struct vfsconf *vfsp, void *data)
1728 {
1729 	int error;
1730 	struct ovfsconf ovfs;
1731 	struct sysctl_req *req = (struct sysctl_req*) data;
1732 
1733 	bzero(&ovfs, sizeof(ovfs));
1734 	ovfs.vfc_vfsops = vfsp->vfc_vfsops;	/* XXX used as flag */
1735 	strcpy(ovfs.vfc_name, vfsp->vfc_name);
1736 	ovfs.vfc_index = vfsp->vfc_typenum;
1737 	ovfs.vfc_refcount = vfsp->vfc_refcount;
1738 	ovfs.vfc_flags = vfsp->vfc_flags;
1739 	error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
1740 	if (error)
1741 		return error; /* abort iteration with error code */
1742 	else
1743 		return 0; /* continue iterating with next element */
1744 }
1745 
1746 static int
1747 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
1748 {
1749 	return vfsconf_each(sysctl_ovfs_conf_iter, (void*)req);
1750 }
1751 
1752 #endif /* 1 || COMPAT_PRELITE2 */
1753 
1754 /*
1755  * Check to see if a filesystem is mounted on a block device.
1756  */
1757 int
1758 vfs_mountedon(struct vnode *vp)
1759 {
1760 	cdev_t dev;
1761 
1762 	if ((dev = vp->v_rdev) == NULL) {
1763 /*		if (vp->v_type != VBLK)
1764 			dev = get_dev(vp->v_uminor, vp->v_umajor); */
1765 	}
1766 	if (dev != NULL && dev->si_mountpoint)
1767 		return (EBUSY);
1768 	return (0);
1769 }
1770 
1771 /*
1772  * Unmount all filesystems. The list is traversed in reverse order
1773  * of mounting to avoid dependencies.
1774  */
1775 
1776 static int vfs_umountall_callback(struct mount *mp, void *data);
1777 
1778 void
1779 vfs_unmountall(void)
1780 {
1781 	int count;
1782 
1783 	do {
1784 		count = mountlist_scan(vfs_umountall_callback,
1785 					NULL, MNTSCAN_REVERSE|MNTSCAN_NOBUSY);
1786 	} while (count);
1787 }
1788 
1789 static
1790 int
1791 vfs_umountall_callback(struct mount *mp, void *data)
1792 {
1793 	int error;
1794 
1795 	error = dounmount(mp, MNT_FORCE);
1796 	if (error) {
1797 		mountlist_remove(mp);
1798 		kprintf("unmount of filesystem mounted from %s failed (",
1799 			mp->mnt_stat.f_mntfromname);
1800 		if (error == EBUSY)
1801 			kprintf("BUSY)\n");
1802 		else
1803 			kprintf("%d)\n", error);
1804 	}
1805 	return(1);
1806 }
1807 
1808 /*
1809  * Checks the mount flags for parameter mp and put the names comma-separated
1810  * into a string buffer buf with a size limit specified by len.
1811  *
1812  * It returns the number of bytes written into buf, and (*errorp) will be
1813  * set to 0, EINVAL (if passed length is 0), or ENOSPC (supplied buffer was
1814  * not large enough).  The buffer will be 0-terminated if len was not 0.
1815  */
1816 size_t
1817 vfs_flagstostr(int flags, const struct mountctl_opt *optp,
1818 	       char *buf, size_t len, int *errorp)
1819 {
1820 	static const struct mountctl_opt optnames[] = {
1821 		{ MNT_ASYNC,            "asynchronous" },
1822 		{ MNT_EXPORTED,         "NFS exported" },
1823 		{ MNT_LOCAL,            "local" },
1824 		{ MNT_NOATIME,          "noatime" },
1825 		{ MNT_NODEV,            "nodev" },
1826 		{ MNT_NOEXEC,           "noexec" },
1827 		{ MNT_NOSUID,           "nosuid" },
1828 		{ MNT_NOSYMFOLLOW,      "nosymfollow" },
1829 		{ MNT_QUOTA,            "with-quotas" },
1830 		{ MNT_RDONLY,           "read-only" },
1831 		{ MNT_SYNCHRONOUS,      "synchronous" },
1832 		{ MNT_UNION,            "union" },
1833 		{ MNT_NOCLUSTERR,       "noclusterr" },
1834 		{ MNT_NOCLUSTERW,       "noclusterw" },
1835 		{ MNT_SUIDDIR,          "suiddir" },
1836 		{ MNT_SOFTDEP,          "soft-updates" },
1837 		{ MNT_IGNORE,           "ignore" },
1838 		{ 0,			NULL}
1839 	};
1840 	int bwritten;
1841 	int bleft;
1842 	int optlen;
1843 	int actsize;
1844 
1845 	*errorp = 0;
1846 	bwritten = 0;
1847 	bleft = len - 1;	/* leave room for trailing \0 */
1848 
1849 	/*
1850 	 * Checks the size of the string. If it contains
1851 	 * any data, then we will append the new flags to
1852 	 * it.
1853 	 */
1854 	actsize = strlen(buf);
1855 	if (actsize > 0)
1856 		buf += actsize;
1857 
1858 	/* Default flags if no flags passed */
1859 	if (optp == NULL)
1860 		optp = optnames;
1861 
1862 	if (bleft < 0) {	/* degenerate case, 0-length buffer */
1863 		*errorp = EINVAL;
1864 		return(0);
1865 	}
1866 
1867 	for (; flags && optp->o_opt; ++optp) {
1868 		if ((flags & optp->o_opt) == 0)
1869 			continue;
1870 		optlen = strlen(optp->o_name);
1871 		if (bwritten || actsize > 0) {
1872 			if (bleft < 2) {
1873 				*errorp = ENOSPC;
1874 				break;
1875 			}
1876 			buf[bwritten++] = ',';
1877 			buf[bwritten++] = ' ';
1878 			bleft -= 2;
1879 		}
1880 		if (bleft < optlen) {
1881 			*errorp = ENOSPC;
1882 			break;
1883 		}
1884 		bcopy(optp->o_name, buf + bwritten, optlen);
1885 		bwritten += optlen;
1886 		bleft -= optlen;
1887 		flags &= ~optp->o_opt;
1888 	}
1889 
1890 	/*
1891 	 * Space already reserved for trailing \0
1892 	 */
1893 	buf[bwritten] = 0;
1894 	return (bwritten);
1895 }
1896 
1897 /*
1898  * Build hash lists of net addresses and hang them off the mount point.
1899  * Called by ufs_mount() to set up the lists of export addresses.
1900  */
1901 static int
1902 vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
1903 		const struct export_args *argp)
1904 {
1905 	struct netcred *np;
1906 	struct radix_node_head *rnh;
1907 	int i;
1908 	struct radix_node *rn;
1909 	struct sockaddr *saddr, *smask = NULL;
1910 	struct domain *dom;
1911 	int error;
1912 
1913 	if (argp->ex_addrlen == 0) {
1914 		if (mp->mnt_flag & MNT_DEFEXPORTED)
1915 			return (EPERM);
1916 		np = &nep->ne_defexported;
1917 		np->netc_exflags = argp->ex_flags;
1918 		np->netc_anon = argp->ex_anon;
1919 		np->netc_anon.cr_ref = 1;
1920 		mp->mnt_flag |= MNT_DEFEXPORTED;
1921 		return (0);
1922 	}
1923 
1924 	if (argp->ex_addrlen < 0 || argp->ex_addrlen > MLEN)
1925 		return (EINVAL);
1926 	if (argp->ex_masklen < 0 || argp->ex_masklen > MLEN)
1927 		return (EINVAL);
1928 
1929 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
1930 	np = (struct netcred *) kmalloc(i, M_NETADDR, M_WAITOK | M_ZERO);
1931 	saddr = (struct sockaddr *) (np + 1);
1932 	if ((error = copyin(argp->ex_addr, (caddr_t) saddr, argp->ex_addrlen)))
1933 		goto out;
1934 	if (saddr->sa_len > argp->ex_addrlen)
1935 		saddr->sa_len = argp->ex_addrlen;
1936 	if (argp->ex_masklen) {
1937 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
1938 		error = copyin(argp->ex_mask, (caddr_t)smask, argp->ex_masklen);
1939 		if (error)
1940 			goto out;
1941 		if (smask->sa_len > argp->ex_masklen)
1942 			smask->sa_len = argp->ex_masklen;
1943 	}
1944 	i = saddr->sa_family;
1945 	if ((rnh = nep->ne_rtable[i]) == NULL) {
1946 		/*
1947 		 * Seems silly to initialize every AF when most are not used,
1948 		 * do so on demand here
1949 		 */
1950 		SLIST_FOREACH(dom, &domains, dom_next)
1951 			if (dom->dom_family == i && dom->dom_rtattach) {
1952 				dom->dom_rtattach((void **) &nep->ne_rtable[i],
1953 				    dom->dom_rtoffset);
1954 				break;
1955 			}
1956 		if ((rnh = nep->ne_rtable[i]) == NULL) {
1957 			error = ENOBUFS;
1958 			goto out;
1959 		}
1960 	}
1961 	rn = (*rnh->rnh_addaddr) ((char *) saddr, (char *) smask, rnh,
1962 	    np->netc_rnodes);
1963 	if (rn == NULL || np != (struct netcred *) rn) {	/* already exists */
1964 		error = EPERM;
1965 		goto out;
1966 	}
1967 	np->netc_exflags = argp->ex_flags;
1968 	np->netc_anon = argp->ex_anon;
1969 	np->netc_anon.cr_ref = 1;
1970 	return (0);
1971 out:
1972 	kfree(np, M_NETADDR);
1973 	return (error);
1974 }
1975 
1976 /* ARGSUSED */
1977 static int
1978 vfs_free_netcred(struct radix_node *rn, void *w)
1979 {
1980 	struct radix_node_head *rnh = (struct radix_node_head *) w;
1981 
1982 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
1983 	kfree((caddr_t) rn, M_NETADDR);
1984 	return (0);
1985 }
1986 
1987 /*
1988  * Free the net address hash lists that are hanging off the mount points.
1989  */
1990 static void
1991 vfs_free_addrlist(struct netexport *nep)
1992 {
1993 	int i;
1994 	struct radix_node_head *rnh;
1995 
1996 	for (i = 0; i <= AF_MAX; i++)
1997 		if ((rnh = nep->ne_rtable[i])) {
1998 			(*rnh->rnh_walktree) (rnh, vfs_free_netcred,
1999 			    (caddr_t) rnh);
2000 			kfree((caddr_t) rnh, M_RTABLE);
2001 			nep->ne_rtable[i] = 0;
2002 		}
2003 }
2004 
2005 int
2006 vfs_export(struct mount *mp, struct netexport *nep,
2007 	   const struct export_args *argp)
2008 {
2009 	int error;
2010 
2011 	if (argp->ex_flags & MNT_DELEXPORT) {
2012 		if (mp->mnt_flag & MNT_EXPUBLIC) {
2013 			vfs_setpublicfs(NULL, NULL, NULL);
2014 			mp->mnt_flag &= ~MNT_EXPUBLIC;
2015 		}
2016 		vfs_free_addrlist(nep);
2017 		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
2018 	}
2019 	if (argp->ex_flags & MNT_EXPORTED) {
2020 		if (argp->ex_flags & MNT_EXPUBLIC) {
2021 			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
2022 				return (error);
2023 			mp->mnt_flag |= MNT_EXPUBLIC;
2024 		}
2025 		if ((error = vfs_hang_addrlist(mp, nep, argp)))
2026 			return (error);
2027 		mp->mnt_flag |= MNT_EXPORTED;
2028 	}
2029 	return (0);
2030 }
2031 
2032 
2033 /*
2034  * Set the publicly exported filesystem (WebNFS). Currently, only
2035  * one public filesystem is possible in the spec (RFC 2054 and 2055)
2036  */
2037 int
2038 vfs_setpublicfs(struct mount *mp, struct netexport *nep,
2039 		const struct export_args *argp)
2040 {
2041 	int error;
2042 	struct vnode *rvp;
2043 	char *cp;
2044 
2045 	/*
2046 	 * mp == NULL -> invalidate the current info, the FS is
2047 	 * no longer exported. May be called from either vfs_export
2048 	 * or unmount, so check if it hasn't already been done.
2049 	 */
2050 	if (mp == NULL) {
2051 		if (nfs_pub.np_valid) {
2052 			nfs_pub.np_valid = 0;
2053 			if (nfs_pub.np_index != NULL) {
2054 				kfree(nfs_pub.np_index, M_TEMP);
2055 				nfs_pub.np_index = NULL;
2056 			}
2057 		}
2058 		return (0);
2059 	}
2060 
2061 	/*
2062 	 * Only one allowed at a time.
2063 	 */
2064 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
2065 		return (EBUSY);
2066 
2067 	/*
2068 	 * Get real filehandle for root of exported FS.
2069 	 */
2070 	bzero((caddr_t)&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
2071 	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
2072 
2073 	if ((error = VFS_ROOT(mp, &rvp)))
2074 		return (error);
2075 
2076 	if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
2077 		return (error);
2078 
2079 	vput(rvp);
2080 
2081 	/*
2082 	 * If an indexfile was specified, pull it in.
2083 	 */
2084 	if (argp->ex_indexfile != NULL) {
2085 		int namelen;
2086 
2087 		error = vn_get_namelen(rvp, &namelen);
2088 		if (error)
2089 			return (error);
2090 		nfs_pub.np_index = kmalloc(namelen, M_TEMP, M_WAITOK);
2091 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
2092 		    namelen, NULL);
2093 		if (!error) {
2094 			/*
2095 			 * Check for illegal filenames.
2096 			 */
2097 			for (cp = nfs_pub.np_index; *cp; cp++) {
2098 				if (*cp == '/') {
2099 					error = EINVAL;
2100 					break;
2101 				}
2102 			}
2103 		}
2104 		if (error) {
2105 			kfree(nfs_pub.np_index, M_TEMP);
2106 			return (error);
2107 		}
2108 	}
2109 
2110 	nfs_pub.np_mount = mp;
2111 	nfs_pub.np_valid = 1;
2112 	return (0);
2113 }
2114 
2115 struct netcred *
2116 vfs_export_lookup(struct mount *mp, struct netexport *nep,
2117 		struct sockaddr *nam)
2118 {
2119 	struct netcred *np;
2120 	struct radix_node_head *rnh;
2121 	struct sockaddr *saddr;
2122 
2123 	np = NULL;
2124 	if (mp->mnt_flag & MNT_EXPORTED) {
2125 		/*
2126 		 * Lookup in the export list first.
2127 		 */
2128 		if (nam != NULL) {
2129 			saddr = nam;
2130 			rnh = nep->ne_rtable[saddr->sa_family];
2131 			if (rnh != NULL) {
2132 				np = (struct netcred *)
2133 					(*rnh->rnh_matchaddr)((char *)saddr,
2134 							      rnh);
2135 				if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
2136 					np = NULL;
2137 			}
2138 		}
2139 		/*
2140 		 * If no address match, use the default if it exists.
2141 		 */
2142 		if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
2143 			np = &nep->ne_defexported;
2144 	}
2145 	return (np);
2146 }
2147 
2148 /*
2149  * perform msync on all vnodes under a mount point.  The mount point must
2150  * be locked.  This code is also responsible for lazy-freeing unreferenced
2151  * vnodes whos VM objects no longer contain pages.
2152  *
2153  * NOTE: MNT_WAIT still skips vnodes in the VXLOCK state.
2154  *
2155  * NOTE: XXX VOP_PUTPAGES and friends requires that the vnode be locked,
2156  * but vnode_pager_putpages() doesn't lock the vnode.  We have to do it
2157  * way up in this high level function.
2158  */
2159 static int vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data);
2160 static int vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data);
2161 
2162 void
2163 vfs_msync(struct mount *mp, int flags)
2164 {
2165 	int vmsc_flags;
2166 
2167 	/*
2168 	 * tmpfs sets this flag to prevent msync(), sync, and the
2169 	 * filesystem periodic syncer from trying to flush VM pages
2170 	 * to swap.  Only pure memory pressure flushes tmpfs VM pages
2171 	 * to swap.
2172 	 */
2173 	if (mp->mnt_kern_flag & MNTK_NOMSYNC)
2174 		return;
2175 
2176 	/*
2177 	 * Ok, scan the vnodes for work.
2178 	 */
2179 	vmsc_flags = VMSC_GETVP;
2180 	if (flags != MNT_WAIT)
2181 		vmsc_flags |= VMSC_NOWAIT;
2182 	vmntvnodescan(mp, vmsc_flags,
2183 		      vfs_msync_scan1, vfs_msync_scan2,
2184 		      (void *)(intptr_t)flags);
2185 }
2186 
2187 /*
2188  * scan1 is a fast pre-check.  There could be hundreds of thousands of
2189  * vnodes, we cannot afford to do anything heavy weight until we have a
2190  * fairly good indication that there is work to do.
2191  */
2192 static
2193 int
2194 vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data)
2195 {
2196 	int flags = (int)(intptr_t)data;
2197 
2198 	if ((vp->v_flag & VRECLAIMED) == 0) {
2199 		if (vshouldmsync(vp))
2200 			return(0);	/* call scan2 */
2201 		if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
2202 		    (vp->v_flag & VOBJDIRTY) &&
2203 		    (flags == MNT_WAIT || vn_islocked(vp) == 0)) {
2204 			return(0);	/* call scan2 */
2205 		}
2206 	}
2207 
2208 	/*
2209 	 * do not call scan2, continue the loop
2210 	 */
2211 	return(-1);
2212 }
2213 
2214 /*
2215  * This callback is handed a locked vnode.
2216  */
2217 static
2218 int
2219 vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data)
2220 {
2221 	vm_object_t obj;
2222 	int flags = (int)(intptr_t)data;
2223 
2224 	if (vp->v_flag & VRECLAIMED)
2225 		return(0);
2226 
2227 	if ((mp->mnt_flag & MNT_RDONLY) == 0 && (vp->v_flag & VOBJDIRTY)) {
2228 		if ((obj = vp->v_object) != NULL) {
2229 			vm_object_page_clean(obj, 0, 0,
2230 			 flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
2231 		}
2232 	}
2233 	return(0);
2234 }
2235 
2236 /*
2237  * Wake up anyone interested in vp because it is being revoked.
2238  */
2239 void
2240 vn_gone(struct vnode *vp)
2241 {
2242 	lwkt_gettoken(&vp->v_token);
2243 	KNOTE(&vp->v_pollinfo.vpi_kqinfo.ki_note, NOTE_REVOKE);
2244 	lwkt_reltoken(&vp->v_token);
2245 }
2246 
2247 /*
2248  * extract the cdev_t from a VBLK or VCHR.  The vnode must have been opened
2249  * (or v_rdev might be NULL).
2250  */
2251 cdev_t
2252 vn_todev(struct vnode *vp)
2253 {
2254 	if (vp->v_type != VBLK && vp->v_type != VCHR)
2255 		return (NULL);
2256 	KKASSERT(vp->v_rdev != NULL);
2257 	return (vp->v_rdev);
2258 }
2259 
2260 /*
2261  * Check if vnode represents a disk device.  The vnode does not need to be
2262  * opened.
2263  *
2264  * MPALMOSTSAFE
2265  */
2266 int
2267 vn_isdisk(struct vnode *vp, int *errp)
2268 {
2269 	cdev_t dev;
2270 
2271 	if (vp->v_type != VCHR) {
2272 		if (errp != NULL)
2273 			*errp = ENOTBLK;
2274 		return (0);
2275 	}
2276 
2277 	dev = vp->v_rdev;
2278 
2279 	if (dev == NULL) {
2280 		if (errp != NULL)
2281 			*errp = ENXIO;
2282 		return (0);
2283 	}
2284 	if (dev_is_good(dev) == 0) {
2285 		if (errp != NULL)
2286 			*errp = ENXIO;
2287 		return (0);
2288 	}
2289 	if ((dev_dflags(dev) & D_DISK) == 0) {
2290 		if (errp != NULL)
2291 			*errp = ENOTBLK;
2292 		return (0);
2293 	}
2294 	if (errp != NULL)
2295 		*errp = 0;
2296 	return (1);
2297 }
2298 
2299 int
2300 vn_get_namelen(struct vnode *vp, int *namelen)
2301 {
2302 	int error;
2303 	register_t retval[2];
2304 
2305 	error = VOP_PATHCONF(vp, _PC_NAME_MAX, retval);
2306 	if (error)
2307 		return (error);
2308 	*namelen = (int)retval[0];
2309 	return (0);
2310 }
2311 
2312 int
2313 vop_write_dirent(int *error, struct uio *uio, ino_t d_ino, uint8_t d_type,
2314 		uint16_t d_namlen, const char *d_name)
2315 {
2316 	struct dirent *dp;
2317 	size_t len;
2318 
2319 	len = _DIRENT_RECLEN(d_namlen);
2320 	if (len > uio->uio_resid)
2321 		return(1);
2322 
2323 	dp = kmalloc(len, M_TEMP, M_WAITOK | M_ZERO);
2324 
2325 	dp->d_ino = d_ino;
2326 	dp->d_namlen = d_namlen;
2327 	dp->d_type = d_type;
2328 	bcopy(d_name, dp->d_name, d_namlen);
2329 
2330 	*error = uiomove((caddr_t)dp, len, uio);
2331 
2332 	kfree(dp, M_TEMP);
2333 
2334 	return(0);
2335 }
2336 
2337 void
2338 vn_mark_atime(struct vnode *vp, struct thread *td)
2339 {
2340 	struct proc *p = td->td_proc;
2341 	struct ucred *cred = p ? p->p_ucred : proc0.p_ucred;
2342 
2343 	if ((vp->v_mount->mnt_flag & (MNT_NOATIME | MNT_RDONLY)) == 0) {
2344 		VOP_MARKATIME(vp, cred);
2345 	}
2346 }
2347