xref: /dragonfly/sys/kern/vfs_subr.c (revision f746689a)
1 /*
2  * Copyright (c) 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  *
38  *	@(#)vfs_subr.c	8.31 (Berkeley) 5/26/95
39  * $FreeBSD: src/sys/kern/vfs_subr.c,v 1.249.2.30 2003/04/04 20:35:57 tegge Exp $
40  * $DragonFly: src/sys/kern/vfs_subr.c,v 1.118 2008/09/17 21:44:18 dillon Exp $
41  */
42 
43 /*
44  * External virtual filesystem routines
45  */
46 #include "opt_ddb.h"
47 
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/buf.h>
51 #include <sys/conf.h>
52 #include <sys/dirent.h>
53 #include <sys/domain.h>
54 #include <sys/eventhandler.h>
55 #include <sys/fcntl.h>
56 #include <sys/file.h>
57 #include <sys/kernel.h>
58 #include <sys/kthread.h>
59 #include <sys/malloc.h>
60 #include <sys/mbuf.h>
61 #include <sys/mount.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 
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 int vfs_fastdev = 1;
94 SYSCTL_INT(_vfs, OID_AUTO, fastdev, CTLFLAG_RW, &vfs_fastdev, 0, "");
95 
96 enum vtype iftovt_tab[16] = {
97 	VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
98 	VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
99 };
100 int vttoif_tab[9] = {
101 	0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
102 	S_IFSOCK, S_IFIFO, S_IFMT,
103 };
104 
105 static int reassignbufcalls;
106 SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW,
107 		&reassignbufcalls, 0, "");
108 static int reassignbufloops;
109 SYSCTL_INT(_vfs, OID_AUTO, reassignbufloops, CTLFLAG_RW,
110 		&reassignbufloops, 0, "");
111 static int reassignbufsortgood;
112 SYSCTL_INT(_vfs, OID_AUTO, reassignbufsortgood, CTLFLAG_RW,
113 		&reassignbufsortgood, 0, "");
114 static int reassignbufsortbad;
115 SYSCTL_INT(_vfs, OID_AUTO, reassignbufsortbad, CTLFLAG_RW,
116 		&reassignbufsortbad, 0, "");
117 static int reassignbufmethod = 1;
118 SYSCTL_INT(_vfs, OID_AUTO, reassignbufmethod, CTLFLAG_RW,
119 		&reassignbufmethod, 0, "");
120 
121 int	nfs_mount_type = -1;
122 static struct lwkt_token spechash_token;
123 struct nfs_public nfs_pub;	/* publicly exported FS */
124 
125 int desiredvnodes;
126 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
127 		&desiredvnodes, 0, "Maximum number of vnodes");
128 
129 static void	vfs_free_addrlist (struct netexport *nep);
130 static int	vfs_free_netcred (struct radix_node *rn, void *w);
131 static int	vfs_hang_addrlist (struct mount *mp, struct netexport *nep,
132 				       const struct export_args *argp);
133 
134 extern int dev_ref_debug;
135 
136 /*
137  * Red black tree functions
138  */
139 static int rb_buf_compare(struct buf *b1, struct buf *b2);
140 RB_GENERATE2(buf_rb_tree, buf, b_rbnode, rb_buf_compare, off_t, b_loffset);
141 RB_GENERATE2(buf_rb_hash, buf, b_rbhash, rb_buf_compare, off_t, b_loffset);
142 
143 static int
144 rb_buf_compare(struct buf *b1, struct buf *b2)
145 {
146 	if (b1->b_loffset < b2->b_loffset)
147 		return(-1);
148 	if (b1->b_loffset > b2->b_loffset)
149 		return(1);
150 	return(0);
151 }
152 
153 /*
154  * Returns non-zero if the vnode is a candidate for lazy msyncing.
155  */
156 static __inline int
157 vshouldmsync(struct vnode *vp)
158 {
159 	if (vp->v_auxrefs != 0 || vp->v_sysref.refcnt > 0)
160 		return (0);		/* other holders */
161 	if (vp->v_object &&
162 	    (vp->v_object->ref_count || vp->v_object->resident_page_count)) {
163 		return (0);
164 	}
165 	return (1);
166 }
167 
168 /*
169  * Initialize the vnode management data structures.
170  *
171  * Called from vfsinit()
172  */
173 void
174 vfs_subr_init(void)
175 {
176 	/*
177 	 * Desiredvnodes is kern.maxvnodes.  We want to scale it
178 	 * according to available system memory but we may also have
179 	 * to limit it based on available KVM, which is capped on 32 bit
180 	 * systems.
181 	 */
182 	desiredvnodes = min(maxproc + vmstats.v_page_count / 4,
183 			    KvaSize / (20 *
184 			    (sizeof(struct vm_object) + sizeof(struct vnode))));
185 
186 	lwkt_token_init(&spechash_token);
187 }
188 
189 /*
190  * Knob to control the precision of file timestamps:
191  *
192  *   0 = seconds only; nanoseconds zeroed.
193  *   1 = seconds and nanoseconds, accurate within 1/HZ.
194  *   2 = seconds and nanoseconds, truncated to microseconds.
195  * >=3 = seconds and nanoseconds, maximum precision.
196  */
197 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
198 
199 static int timestamp_precision = TSP_SEC;
200 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
201 		&timestamp_precision, 0, "");
202 
203 /*
204  * Get a current timestamp.
205  */
206 void
207 vfs_timestamp(struct timespec *tsp)
208 {
209 	struct timeval tv;
210 
211 	switch (timestamp_precision) {
212 	case TSP_SEC:
213 		tsp->tv_sec = time_second;
214 		tsp->tv_nsec = 0;
215 		break;
216 	case TSP_HZ:
217 		getnanotime(tsp);
218 		break;
219 	case TSP_USEC:
220 		microtime(&tv);
221 		TIMEVAL_TO_TIMESPEC(&tv, tsp);
222 		break;
223 	case TSP_NSEC:
224 	default:
225 		nanotime(tsp);
226 		break;
227 	}
228 }
229 
230 /*
231  * Set vnode attributes to VNOVAL
232  */
233 void
234 vattr_null(struct vattr *vap)
235 {
236 	vap->va_type = VNON;
237 	vap->va_size = VNOVAL;
238 	vap->va_bytes = VNOVAL;
239 	vap->va_mode = VNOVAL;
240 	vap->va_nlink = VNOVAL;
241 	vap->va_uid = VNOVAL;
242 	vap->va_gid = VNOVAL;
243 	vap->va_fsid = VNOVAL;
244 	vap->va_fileid = VNOVAL;
245 	vap->va_blocksize = VNOVAL;
246 	vap->va_rmajor = VNOVAL;
247 	vap->va_rminor = VNOVAL;
248 	vap->va_atime.tv_sec = VNOVAL;
249 	vap->va_atime.tv_nsec = VNOVAL;
250 	vap->va_mtime.tv_sec = VNOVAL;
251 	vap->va_mtime.tv_nsec = VNOVAL;
252 	vap->va_ctime.tv_sec = VNOVAL;
253 	vap->va_ctime.tv_nsec = VNOVAL;
254 	vap->va_flags = VNOVAL;
255 	vap->va_gen = VNOVAL;
256 	vap->va_vaflags = 0;
257 	vap->va_fsmid = VNOVAL;
258 	/* va_*_uuid fields are only valid if related flags are set */
259 }
260 
261 /*
262  * Flush out and invalidate all buffers associated with a vnode.
263  *
264  * vp must be locked.
265  */
266 static int vinvalbuf_bp(struct buf *bp, void *data);
267 
268 struct vinvalbuf_bp_info {
269 	struct vnode *vp;
270 	int slptimeo;
271 	int lkflags;
272 	int flags;
273 };
274 
275 void
276 vupdatefsmid(struct vnode *vp)
277 {
278 	atomic_set_int(&vp->v_flag, VFSMID);
279 }
280 
281 int
282 vinvalbuf(struct vnode *vp, int flags, int slpflag, int slptimeo)
283 {
284 	struct vinvalbuf_bp_info info;
285 	int error;
286 	vm_object_t object;
287 
288 	/*
289 	 * If we are being asked to save, call fsync to ensure that the inode
290 	 * is updated.
291 	 */
292 	if (flags & V_SAVE) {
293 		crit_enter();
294 		while (vp->v_track_write.bk_active) {
295 			vp->v_track_write.bk_waitflag = 1;
296 			error = tsleep(&vp->v_track_write, slpflag,
297 					"vinvlbuf", slptimeo);
298 			if (error) {
299 				crit_exit();
300 				return (error);
301 			}
302 		}
303 		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
304 			crit_exit();
305 			if ((error = VOP_FSYNC(vp, MNT_WAIT)) != 0)
306 				return (error);
307 			crit_enter();
308 
309 			/*
310 			 * Dirty bufs may be left or generated via races
311 			 * in circumstances where vinvalbuf() is called on
312 			 * a vnode not undergoing reclamation.   Only
313 			 * panic if we are trying to reclaim the vnode.
314 			 */
315 			if ((vp->v_flag & VRECLAIMED) &&
316 			    (vp->v_track_write.bk_active > 0 ||
317 			    !RB_EMPTY(&vp->v_rbdirty_tree))) {
318 				panic("vinvalbuf: dirty bufs");
319 			}
320 		}
321 		crit_exit();
322   	}
323 	crit_enter();
324 	info.slptimeo = slptimeo;
325 	info.lkflags = LK_EXCLUSIVE | LK_SLEEPFAIL;
326 	if (slpflag & PCATCH)
327 		info.lkflags |= LK_PCATCH;
328 	info.flags = flags;
329 	info.vp = vp;
330 
331 	/*
332 	 * Flush the buffer cache until nothing is left.
333 	 */
334 	while (!RB_EMPTY(&vp->v_rbclean_tree) ||
335 	    !RB_EMPTY(&vp->v_rbdirty_tree)) {
336 		error = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree, NULL,
337 				vinvalbuf_bp, &info);
338 		if (error == 0) {
339 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
340 					vinvalbuf_bp, &info);
341 		}
342 	}
343 
344 	/*
345 	 * Wait for I/O to complete.  XXX needs cleaning up.  The vnode can
346 	 * have write I/O in-progress but if there is a VM object then the
347 	 * VM object can also have read-I/O in-progress.
348 	 */
349 	do {
350 		while (vp->v_track_write.bk_active > 0) {
351 			vp->v_track_write.bk_waitflag = 1;
352 			tsleep(&vp->v_track_write, 0, "vnvlbv", 0);
353 		}
354 		if ((object = vp->v_object) != NULL) {
355 			while (object->paging_in_progress)
356 				vm_object_pip_sleep(object, "vnvlbx");
357 		}
358 	} while (vp->v_track_write.bk_active > 0);
359 
360 	crit_exit();
361 
362 	/*
363 	 * Destroy the copy in the VM cache, too.
364 	 */
365 	if ((object = vp->v_object) != NULL) {
366 		vm_object_page_remove(object, 0, 0,
367 			(flags & V_SAVE) ? TRUE : FALSE);
368 	}
369 
370 	if (!RB_EMPTY(&vp->v_rbdirty_tree) || !RB_EMPTY(&vp->v_rbclean_tree))
371 		panic("vinvalbuf: flush failed");
372 	if (!RB_EMPTY(&vp->v_rbhash_tree))
373 		panic("vinvalbuf: flush failed, buffers still present");
374 	return (0);
375 }
376 
377 static int
378 vinvalbuf_bp(struct buf *bp, void *data)
379 {
380 	struct vinvalbuf_bp_info *info = data;
381 	int error;
382 
383 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
384 		error = BUF_TIMELOCK(bp, info->lkflags,
385 				     "vinvalbuf", info->slptimeo);
386 		if (error == 0) {
387 			BUF_UNLOCK(bp);
388 			error = ENOLCK;
389 		}
390 		if (error == ENOLCK)
391 			return(0);
392 		return (-error);
393 	}
394 
395 	KKASSERT(bp->b_vp == info->vp);
396 
397 	/*
398 	 * XXX Since there are no node locks for NFS, I
399 	 * believe there is a slight chance that a delayed
400 	 * write will occur while sleeping just above, so
401 	 * check for it.  Note that vfs_bio_awrite expects
402 	 * buffers to reside on a queue, while bwrite() and
403 	 * brelse() do not.
404 	 *
405 	 * NOTE:  NO B_LOCKED CHECK.  Also no buf_checkwrite()
406 	 * check.  This code will write out the buffer, period.
407 	 */
408 	if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
409 	    (info->flags & V_SAVE)) {
410 		if (bp->b_vp == info->vp) {
411 			if (bp->b_flags & B_CLUSTEROK) {
412 				vfs_bio_awrite(bp);
413 			} else {
414 				bremfree(bp);
415 				bp->b_flags |= B_ASYNC;
416 				bwrite(bp);
417 			}
418 		} else {
419 			bremfree(bp);
420 			bwrite(bp);
421 		}
422 	} else if (info->flags & V_SAVE) {
423 		/*
424 		 * Cannot set B_NOCACHE on a clean buffer as this will
425 		 * destroy the VM backing store which might actually
426 		 * be dirty (and unsynchronized).
427 		 */
428 		bremfree(bp);
429 		bp->b_flags |= (B_INVAL | B_RELBUF);
430 		bp->b_flags &= ~B_ASYNC;
431 		brelse(bp);
432 	} else {
433 		bremfree(bp);
434 		bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
435 		bp->b_flags &= ~B_ASYNC;
436 		brelse(bp);
437 	}
438 	return(0);
439 }
440 
441 /*
442  * Truncate a file's buffer and pages to a specified length.  This
443  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
444  * sync activity.
445  *
446  * The vnode must be locked.
447  */
448 static int vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data);
449 static int vtruncbuf_bp_trunc(struct buf *bp, void *data);
450 static int vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data);
451 static int vtruncbuf_bp_metasync(struct buf *bp, void *data);
452 
453 int
454 vtruncbuf(struct vnode *vp, off_t length, int blksize)
455 {
456 	off_t truncloffset;
457 	int count;
458 	const char *filename;
459 
460 	/*
461 	 * Round up to the *next* block, then destroy the buffers in question.
462 	 * Since we are only removing some of the buffers we must rely on the
463 	 * scan count to determine whether a loop is necessary.
464 	 */
465 	if ((count = (int)(length % blksize)) != 0)
466 		truncloffset = length + (blksize - count);
467 	else
468 		truncloffset = length;
469 
470 	crit_enter();
471 	do {
472 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
473 				vtruncbuf_bp_trunc_cmp,
474 				vtruncbuf_bp_trunc, &truncloffset);
475 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
476 				vtruncbuf_bp_trunc_cmp,
477 				vtruncbuf_bp_trunc, &truncloffset);
478 	} while(count);
479 
480 	/*
481 	 * For safety, fsync any remaining metadata if the file is not being
482 	 * truncated to 0.  Since the metadata does not represent the entire
483 	 * dirty list we have to rely on the hit count to ensure that we get
484 	 * all of it.
485 	 */
486 	if (length > 0) {
487 		do {
488 			count = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
489 					vtruncbuf_bp_metasync_cmp,
490 					vtruncbuf_bp_metasync, vp);
491 		} while (count);
492 	}
493 
494 	/*
495 	 * Clean out any left over VM backing store.
496 	 */
497 	crit_exit();
498 
499 	vnode_pager_setsize(vp, length);
500 
501 	crit_enter();
502 
503 	/*
504 	 * It is possible to have in-progress I/O from buffers that were
505 	 * not part of the truncation.  This should not happen if we
506 	 * are truncating to 0-length.
507 	 */
508 	filename = TAILQ_FIRST(&vp->v_namecache) ?
509 		   TAILQ_FIRST(&vp->v_namecache)->nc_name : "?";
510 
511 	while ((count = vp->v_track_write.bk_active) > 0) {
512 		vp->v_track_write.bk_waitflag = 1;
513 		tsleep(&vp->v_track_write, 0, "vbtrunc", 0);
514 		if (length == 0) {
515 			kprintf("Warning: vtruncbuf(): Had to wait for "
516 			       "%d buffer I/Os to finish in %s\n",
517 			       count, filename);
518 		}
519 	}
520 
521 	/*
522 	 * Make sure no buffers were instantiated while we were trying
523 	 * to clean out the remaining VM pages.  This could occur due
524 	 * to busy dirty VM pages being flushed out to disk.
525 	 */
526 	do {
527 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
528 				vtruncbuf_bp_trunc_cmp,
529 				vtruncbuf_bp_trunc, &truncloffset);
530 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
531 				vtruncbuf_bp_trunc_cmp,
532 				vtruncbuf_bp_trunc, &truncloffset);
533 		if (count) {
534 			kprintf("Warning: vtruncbuf():  Had to re-clean %d "
535 			       "left over buffers in %s\n", count, filename);
536 		}
537 	} while(count);
538 
539 	crit_exit();
540 
541 	return (0);
542 }
543 
544 /*
545  * The callback buffer is beyond the new file EOF and must be destroyed.
546  * Note that the compare function must conform to the RB_SCAN's requirements.
547  */
548 static
549 int
550 vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data)
551 {
552 	if (bp->b_loffset >= *(off_t *)data)
553 		return(0);
554 	return(-1);
555 }
556 
557 static
558 int
559 vtruncbuf_bp_trunc(struct buf *bp, void *data)
560 {
561 	/*
562 	 * Do not try to use a buffer we cannot immediately lock, but sleep
563 	 * anyway to prevent a livelock.  The code will loop until all buffers
564 	 * can be acted upon.
565 	 */
566 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
567 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
568 			BUF_UNLOCK(bp);
569 	} else {
570 		bremfree(bp);
571 		bp->b_flags |= (B_INVAL | B_RELBUF | B_NOCACHE);
572 		bp->b_flags &= ~B_ASYNC;
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)
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 vnode *vp = data;
595 
596 	if (bp->b_flags & B_DELWRI) {
597 		/*
598 		 * Do not try to use a buffer we cannot immediately lock,
599 		 * but sleep anyway to prevent a livelock.  The code will
600 		 * loop until all buffers can be acted upon.
601 		 */
602 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
603 			if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
604 				BUF_UNLOCK(bp);
605 		} else {
606 			bremfree(bp);
607 			if (bp->b_vp == vp) {
608 				bp->b_flags |= B_ASYNC;
609 			} else {
610 				bp->b_flags &= ~B_ASYNC;
611 			}
612 			bwrite(bp);
613 		}
614 		return(1);
615 	} else {
616 		return(0);
617 	}
618 }
619 
620 /*
621  * vfsync - implements a multipass fsync on a file which understands
622  * dependancies and meta-data.  The passed vnode must be locked.  The
623  * waitfor argument may be MNT_WAIT or MNT_NOWAIT, or MNT_LAZY.
624  *
625  * When fsyncing data asynchronously just do one consolidated pass starting
626  * with the most negative block number.  This may not get all the data due
627  * to dependancies.
628  *
629  * When fsyncing data synchronously do a data pass, then a metadata pass,
630  * then do additional data+metadata passes to try to get all the data out.
631  */
632 static int vfsync_wait_output(struct vnode *vp,
633 			    int (*waitoutput)(struct vnode *, struct thread *));
634 static int vfsync_data_only_cmp(struct buf *bp, void *data);
635 static int vfsync_meta_only_cmp(struct buf *bp, void *data);
636 static int vfsync_lazy_range_cmp(struct buf *bp, void *data);
637 static int vfsync_bp(struct buf *bp, void *data);
638 
639 struct vfsync_info {
640 	struct vnode *vp;
641 	int synchronous;
642 	int syncdeps;
643 	int lazycount;
644 	int lazylimit;
645 	int skippedbufs;
646 	int (*checkdef)(struct buf *);
647 };
648 
649 int
650 vfsync(struct vnode *vp, int waitfor, int passes,
651 	int (*checkdef)(struct buf *),
652 	int (*waitoutput)(struct vnode *, struct thread *))
653 {
654 	struct vfsync_info info;
655 	int error;
656 
657 	bzero(&info, sizeof(info));
658 	info.vp = vp;
659 	if ((info.checkdef = checkdef) == NULL)
660 		info.syncdeps = 1;
661 
662 	crit_enter_id("vfsync");
663 
664 	switch(waitfor) {
665 	case MNT_LAZY:
666 		/*
667 		 * Lazy (filesystem syncer typ) Asynchronous plus limit the
668 		 * number of data (not meta) pages we try to flush to 1MB.
669 		 * A non-zero return means that lazy limit was reached.
670 		 */
671 		info.lazylimit = 1024 * 1024;
672 		info.syncdeps = 1;
673 		error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
674 				vfsync_lazy_range_cmp, vfsync_bp, &info);
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_to_worklist(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 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
689 			vfsync_bp, &info);
690 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_meta_only_cmp,
691 			vfsync_bp, &info);
692 		error = 0;
693 		break;
694 	default:
695 		/*
696 		 * Synchronous.  Do a data-only pass, then a meta-data+data
697 		 * pass, then additional integrated passes to try to get
698 		 * all the dependancies flushed.
699 		 */
700 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
701 			vfsync_bp, &info);
702 		error = vfsync_wait_output(vp, waitoutput);
703 		if (error == 0) {
704 			info.skippedbufs = 0;
705 			RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
706 				vfsync_bp, &info);
707 			error = vfsync_wait_output(vp, waitoutput);
708 			if (info.skippedbufs)
709 				kprintf("Warning: vfsync skipped %d dirty bufs in pass2!\n", info.skippedbufs);
710 		}
711 		while (error == 0 && passes > 0 &&
712 		    !RB_EMPTY(&vp->v_rbdirty_tree)) {
713 			if (--passes == 0) {
714 				info.synchronous = 1;
715 				info.syncdeps = 1;
716 			}
717 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
718 				vfsync_bp, &info);
719 			if (error < 0)
720 				error = -error;
721 			info.syncdeps = 1;
722 			if (error == 0)
723 				error = vfsync_wait_output(vp, waitoutput);
724 		}
725 		break;
726 	}
727 	crit_exit_id("vfsync");
728 	return(error);
729 }
730 
731 static int
732 vfsync_wait_output(struct vnode *vp, int (*waitoutput)(struct vnode *, struct thread *))
733 {
734 	int error = 0;
735 
736 	while (vp->v_track_write.bk_active) {
737 		vp->v_track_write.bk_waitflag = 1;
738 		tsleep(&vp->v_track_write, 0, "fsfsn", 0);
739 	}
740 	if (waitoutput)
741 		error = waitoutput(vp, curthread);
742 	return(error);
743 }
744 
745 static int
746 vfsync_data_only_cmp(struct buf *bp, void *data)
747 {
748 	if (bp->b_loffset < 0)
749 		return(-1);
750 	return(0);
751 }
752 
753 static int
754 vfsync_meta_only_cmp(struct buf *bp, void *data)
755 {
756 	if (bp->b_loffset < 0)
757 		return(0);
758 	return(1);
759 }
760 
761 static int
762 vfsync_lazy_range_cmp(struct buf *bp, void *data)
763 {
764 	struct vfsync_info *info = data;
765 	if (bp->b_loffset < info->vp->v_lazyw)
766 		return(-1);
767 	return(0);
768 }
769 
770 static int
771 vfsync_bp(struct buf *bp, void *data)
772 {
773 	struct vfsync_info *info = data;
774 	struct vnode *vp = info->vp;
775 	int error;
776 
777 	/*
778 	 * if syncdeps is not set we do not try to write buffers which have
779 	 * dependancies.
780 	 */
781 	if (!info->synchronous && info->syncdeps == 0 && info->checkdef(bp))
782 		return(0);
783 
784 	/*
785 	 * Ignore buffers that we cannot immediately lock.  XXX
786 	 */
787 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
788 		kprintf("Warning: vfsync_bp skipping dirty buffer %p\n", bp);
789 		++info->skippedbufs;
790 		return(0);
791 	}
792 	if ((bp->b_flags & B_DELWRI) == 0)
793 		panic("vfsync_bp: buffer not dirty");
794 	if (vp != bp->b_vp)
795 		panic("vfsync_bp: buffer vp mismatch");
796 
797 	/*
798 	 * B_NEEDCOMMIT (primarily used by NFS) is a state where the buffer
799 	 * has been written but an additional handshake with the device
800 	 * is required before we can dispose of the buffer.  We have no idea
801 	 * how to do this so we have to skip these buffers.
802 	 */
803 	if (bp->b_flags & B_NEEDCOMMIT) {
804 		BUF_UNLOCK(bp);
805 		return(0);
806 	}
807 
808 	/*
809 	 * Ask bioops if it is ok to sync
810 	 */
811 	if (LIST_FIRST(&bp->b_dep) != NULL && buf_checkwrite(bp)) {
812 		bremfree(bp);
813 		brelse(bp);
814 		return(0);
815 	}
816 
817 	if (info->synchronous) {
818 		/*
819 		 * Synchronous flushing.  An error may be returned.
820 		 */
821 		bremfree(bp);
822 		crit_exit_id("vfsync");
823 		error = bwrite(bp);
824 		crit_enter_id("vfsync");
825 	} else {
826 		/*
827 		 * Asynchronous flushing.  A negative return value simply
828 		 * stops the scan and is not considered an error.  We use
829 		 * this to support limited MNT_LAZY flushes.
830 		 */
831 		vp->v_lazyw = bp->b_loffset;
832 		if ((vp->v_flag & VOBJBUF) && (bp->b_flags & B_CLUSTEROK)) {
833 			info->lazycount += vfs_bio_awrite(bp);
834 		} else {
835 			info->lazycount += bp->b_bufsize;
836 			bremfree(bp);
837 			crit_exit_id("vfsync");
838 			bawrite(bp);
839 			crit_enter_id("vfsync");
840 		}
841 		if (info->lazylimit && info->lazycount >= info->lazylimit)
842 			error = 1;
843 		else
844 			error = 0;
845 	}
846 	return(-error);
847 }
848 
849 /*
850  * Associate a buffer with a vnode.
851  */
852 void
853 bgetvp(struct vnode *vp, struct buf *bp)
854 {
855 	KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));
856 	KKASSERT((bp->b_flags & (B_HASHED|B_DELWRI|B_VNCLEAN|B_VNDIRTY)) == 0);
857 
858 	vhold(vp);
859 	/*
860 	 * Insert onto list for new vnode.
861 	 */
862 	crit_enter();
863 	bp->b_vp = vp;
864 	bp->b_flags |= B_HASHED;
865 	if (buf_rb_hash_RB_INSERT(&vp->v_rbhash_tree, bp))
866 		panic("reassignbuf: dup lblk vp %p bp %p", vp, bp);
867 
868 	bp->b_flags |= B_VNCLEAN;
869 	if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp))
870 		panic("reassignbuf: dup lblk/clean vp %p bp %p", vp, bp);
871 	crit_exit();
872 }
873 
874 /*
875  * Disassociate a buffer from a vnode.
876  */
877 void
878 brelvp(struct buf *bp)
879 {
880 	struct vnode *vp;
881 
882 	KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
883 
884 	/*
885 	 * Delete from old vnode list, if on one.
886 	 */
887 	vp = bp->b_vp;
888 	crit_enter();
889 	if (bp->b_flags & (B_VNDIRTY | B_VNCLEAN)) {
890 		if (bp->b_flags & B_VNDIRTY)
891 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
892 		else
893 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
894 		bp->b_flags &= ~(B_VNDIRTY | B_VNCLEAN);
895 	}
896 	if (bp->b_flags & B_HASHED) {
897 		buf_rb_hash_RB_REMOVE(&vp->v_rbhash_tree, bp);
898 		bp->b_flags &= ~B_HASHED;
899 	}
900 	if ((vp->v_flag & VONWORKLST) && RB_EMPTY(&vp->v_rbdirty_tree)) {
901 		vp->v_flag &= ~VONWORKLST;
902 		LIST_REMOVE(vp, v_synclist);
903 	}
904 	crit_exit();
905 	bp->b_vp = NULL;
906 	vdrop(vp);
907 }
908 
909 /*
910  * Reassign the buffer to the proper clean/dirty list based on B_DELWRI.
911  * This routine is called when the state of the B_DELWRI bit is changed.
912  */
913 void
914 reassignbuf(struct buf *bp)
915 {
916 	struct vnode *vp = bp->b_vp;
917 	int delay;
918 
919 	KKASSERT(vp != NULL);
920 	++reassignbufcalls;
921 
922 	/*
923 	 * B_PAGING flagged buffers cannot be reassigned because their vp
924 	 * is not fully linked in.
925 	 */
926 	if (bp->b_flags & B_PAGING)
927 		panic("cannot reassign paging buffer");
928 
929 	crit_enter();
930 	if (bp->b_flags & B_DELWRI) {
931 		/*
932 		 * Move to the dirty list, add the vnode to the worklist
933 		 */
934 		if (bp->b_flags & B_VNCLEAN) {
935 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
936 			bp->b_flags &= ~B_VNCLEAN;
937 		}
938 		if ((bp->b_flags & B_VNDIRTY) == 0) {
939 			if (buf_rb_tree_RB_INSERT(&vp->v_rbdirty_tree, bp)) {
940 				panic("reassignbuf: dup lblk vp %p bp %p",
941 				      vp, bp);
942 			}
943 			bp->b_flags |= B_VNDIRTY;
944 		}
945 		if ((vp->v_flag & VONWORKLST) == 0) {
946 			switch (vp->v_type) {
947 			case VDIR:
948 				delay = dirdelay;
949 				break;
950 			case VCHR:
951 			case VBLK:
952 				if (vp->v_rdev &&
953 				    vp->v_rdev->si_mountpoint != NULL) {
954 					delay = metadelay;
955 					break;
956 				}
957 				/* fall through */
958 			default:
959 				delay = filedelay;
960 			}
961 			vn_syncer_add_to_worklist(vp, delay);
962 		}
963 	} else {
964 		/*
965 		 * Move to the clean list, remove the vnode from the worklist
966 		 * if no dirty blocks remain.
967 		 */
968 		if (bp->b_flags & B_VNDIRTY) {
969 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
970 			bp->b_flags &= ~B_VNDIRTY;
971 		}
972 		if ((bp->b_flags & B_VNCLEAN) == 0) {
973 			if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp)) {
974 				panic("reassignbuf: dup lblk vp %p bp %p",
975 				      vp, bp);
976 			}
977 			bp->b_flags |= B_VNCLEAN;
978 		}
979 		if ((vp->v_flag & VONWORKLST) &&
980 		    RB_EMPTY(&vp->v_rbdirty_tree)) {
981 			vp->v_flag &= ~VONWORKLST;
982 			LIST_REMOVE(vp, v_synclist);
983 		}
984 	}
985 	crit_exit();
986 }
987 
988 /*
989  * Create a vnode for a block device.
990  * Used for mounting the root file system.
991  */
992 int
993 bdevvp(cdev_t dev, struct vnode **vpp)
994 {
995 	struct vnode *vp;
996 	struct vnode *nvp;
997 	int error;
998 
999 	if (dev == NULL) {
1000 		*vpp = NULLVP;
1001 		return (ENXIO);
1002 	}
1003 	error = getspecialvnode(VT_NON, NULL, &spec_vnode_vops_p, &nvp, 0, 0);
1004 	if (error) {
1005 		*vpp = NULLVP;
1006 		return (error);
1007 	}
1008 	vp = nvp;
1009 	vp->v_type = VCHR;
1010 	vp->v_umajor = dev->si_umajor;
1011 	vp->v_uminor = dev->si_uminor;
1012 	vx_unlock(vp);
1013 	*vpp = vp;
1014 	return (0);
1015 }
1016 
1017 int
1018 v_associate_rdev(struct vnode *vp, cdev_t dev)
1019 {
1020 	lwkt_tokref ilock;
1021 
1022 	if (dev == NULL)
1023 		return(ENXIO);
1024 	if (dev_is_good(dev) == 0)
1025 		return(ENXIO);
1026 	KKASSERT(vp->v_rdev == NULL);
1027 	if (dev_ref_debug)
1028 		kprintf("Z1");
1029 	vp->v_rdev = reference_dev(dev);
1030 	lwkt_gettoken(&ilock, &spechash_token);
1031 	SLIST_INSERT_HEAD(&dev->si_hlist, vp, v_cdevnext);
1032 	lwkt_reltoken(&ilock);
1033 	return(0);
1034 }
1035 
1036 void
1037 v_release_rdev(struct vnode *vp)
1038 {
1039 	lwkt_tokref ilock;
1040 	cdev_t dev;
1041 
1042 	if ((dev = vp->v_rdev) != NULL) {
1043 		lwkt_gettoken(&ilock, &spechash_token);
1044 		SLIST_REMOVE(&dev->si_hlist, vp, vnode, v_cdevnext);
1045 		vp->v_rdev = NULL;
1046 		release_dev(dev);
1047 		lwkt_reltoken(&ilock);
1048 	}
1049 }
1050 
1051 /*
1052  * Add a vnode to the alias list hung off the cdev_t.  We only associate
1053  * the device number with the vnode.  The actual device is not associated
1054  * until the vnode is opened (usually in spec_open()), and will be
1055  * disassociated on last close.
1056  */
1057 void
1058 addaliasu(struct vnode *nvp, int x, int y)
1059 {
1060 	if (nvp->v_type != VBLK && nvp->v_type != VCHR)
1061 		panic("addaliasu on non-special vnode");
1062 	nvp->v_umajor = x;
1063 	nvp->v_uminor = y;
1064 }
1065 
1066 /*
1067  * Simple call that a filesystem can make to try to get rid of a
1068  * vnode.  It will fail if anyone is referencing the vnode (including
1069  * the caller).
1070  *
1071  * The filesystem can check whether its in-memory inode structure still
1072  * references the vp on return.
1073  */
1074 void
1075 vclean_unlocked(struct vnode *vp)
1076 {
1077 	vx_get(vp);
1078 	if (sysref_isactive(&vp->v_sysref) == 0)
1079 		vgone_vxlocked(vp);
1080 	vx_put(vp);
1081 }
1082 
1083 /*
1084  * Disassociate a vnode from its underlying filesystem.
1085  *
1086  * The vnode must be VX locked and referenced.  In all normal situations
1087  * there are no active references.  If vclean_vxlocked() is called while
1088  * there are active references, the vnode is being ripped out and we have
1089  * to call VOP_CLOSE() as appropriate before we can reclaim it.
1090  */
1091 void
1092 vclean_vxlocked(struct vnode *vp, int flags)
1093 {
1094 	int active;
1095 	int n;
1096 	vm_object_t object;
1097 
1098 	/*
1099 	 * If the vnode has already been reclaimed we have nothing to do.
1100 	 */
1101 	if (vp->v_flag & VRECLAIMED)
1102 		return;
1103 	vp->v_flag |= VRECLAIMED;
1104 
1105 	/*
1106 	 * Scrap the vfs cache
1107 	 */
1108 	while (cache_inval_vp(vp, 0) != 0) {
1109 		kprintf("Warning: vnode %p clean/cache_resolution race detected\n", vp);
1110 		tsleep(vp, 0, "vclninv", 2);
1111 	}
1112 
1113 	/*
1114 	 * Check to see if the vnode is in use. If so we have to reference it
1115 	 * before we clean it out so that its count cannot fall to zero and
1116 	 * generate a race against ourselves to recycle it.
1117 	 */
1118 	active = sysref_isactive(&vp->v_sysref);
1119 
1120 	/*
1121 	 * Clean out any buffers associated with the vnode and destroy its
1122 	 * object, if it has one.
1123 	 */
1124 	vinvalbuf(vp, V_SAVE, 0, 0);
1125 
1126 	/*
1127 	 * If purging an active vnode (typically during a forced unmount
1128 	 * or reboot), it must be closed and deactivated before being
1129 	 * reclaimed.  This isn't really all that safe, but what can
1130 	 * we do? XXX.
1131 	 *
1132 	 * Note that neither of these routines unlocks the vnode.
1133 	 */
1134 	if (active && (flags & DOCLOSE)) {
1135 		while ((n = vp->v_opencount) != 0) {
1136 			if (vp->v_writecount)
1137 				VOP_CLOSE(vp, FWRITE|FNONBLOCK);
1138 			else
1139 				VOP_CLOSE(vp, FNONBLOCK);
1140 			if (vp->v_opencount == n) {
1141 				kprintf("Warning: unable to force-close"
1142 				       " vnode %p\n", vp);
1143 				break;
1144 			}
1145 		}
1146 	}
1147 
1148 	/*
1149 	 * If the vnode has not been deactivated, deactivated it.  Deactivation
1150 	 * can create new buffers and VM pages so we have to call vinvalbuf()
1151 	 * again to make sure they all get flushed.
1152 	 *
1153 	 * This can occur if a file with a link count of 0 needs to be
1154 	 * truncated.
1155 	 */
1156 	if ((vp->v_flag & VINACTIVE) == 0) {
1157 		vp->v_flag |= VINACTIVE;
1158 		VOP_INACTIVE(vp);
1159 		vinvalbuf(vp, V_SAVE, 0, 0);
1160 	}
1161 
1162 	/*
1163 	 * If the vnode has an object, destroy it.
1164 	 */
1165 	if ((object = vp->v_object) != NULL) {
1166 		if (object->ref_count == 0) {
1167 			if ((object->flags & OBJ_DEAD) == 0)
1168 				vm_object_terminate(object);
1169 		} else {
1170 			vm_pager_deallocate(object);
1171 		}
1172 		vp->v_flag &= ~VOBJBUF;
1173 	}
1174 	KKASSERT((vp->v_flag & VOBJBUF) == 0);
1175 
1176 	/*
1177 	 * Reclaim the vnode.
1178 	 */
1179 	if (VOP_RECLAIM(vp))
1180 		panic("vclean: cannot reclaim");
1181 
1182 	/*
1183 	 * Done with purge, notify sleepers of the grim news.
1184 	 */
1185 	vp->v_ops = &dead_vnode_vops_p;
1186 	vn_pollgone(vp);
1187 	vp->v_tag = VT_NON;
1188 
1189 	/*
1190 	 * If we are destroying an active vnode, reactivate it now that
1191 	 * we have reassociated it with deadfs.  This prevents the system
1192 	 * from crashing on the vnode due to it being unexpectedly marked
1193 	 * as inactive or reclaimed.
1194 	 */
1195 	if (active && (flags & DOCLOSE)) {
1196 		vp->v_flag &= ~(VINACTIVE|VRECLAIMED);
1197 	}
1198 }
1199 
1200 /*
1201  * Eliminate all activity associated with the requested vnode
1202  * and with all vnodes aliased to the requested vnode.
1203  *
1204  * The vnode must be referenced but should not be locked.
1205  */
1206 int
1207 vrevoke(struct vnode *vp, struct ucred *cred)
1208 {
1209 	struct vnode *vq;
1210 	lwkt_tokref ilock;
1211 	cdev_t dev;
1212 	int error;
1213 
1214 	/*
1215 	 * If the vnode has a device association, scrap all vnodes associated
1216 	 * with the device.  Don't let the device disappear on us while we
1217 	 * are scrapping the vnodes.
1218 	 *
1219 	 * The passed vp will probably show up in the list, do not VX lock
1220 	 * it twice!
1221 	 */
1222 	if (vp->v_type != VCHR) {
1223 		error = fdrevoke(vp, DTYPE_VNODE, cred);
1224 		return (error);
1225 	}
1226 	if ((dev = vp->v_rdev) == NULL) {
1227 		if ((dev = get_dev(vp->v_umajor, vp->v_uminor)) == NULL)
1228 			return(0);
1229 	}
1230 	reference_dev(dev);
1231 	lwkt_gettoken(&ilock, &spechash_token);
1232 	while ((vq = SLIST_FIRST(&dev->si_hlist)) != NULL) {
1233 		vref(vq);
1234 		fdrevoke(vq, DTYPE_VNODE, cred);
1235 		v_release_rdev(vq);
1236 		vrele(vq);
1237 	}
1238 	lwkt_reltoken(&ilock);
1239 	release_dev(dev);
1240 	return (0);
1241 }
1242 
1243 /*
1244  * This is called when the object underlying a vnode is being destroyed,
1245  * such as in a remove().  Try to recycle the vnode immediately if the
1246  * only active reference is our reference.
1247  *
1248  * Directory vnodes in the namecache with children cannot be immediately
1249  * recycled because numerous VOP_N*() ops require them to be stable.
1250  */
1251 int
1252 vrecycle(struct vnode *vp)
1253 {
1254 	if (vp->v_sysref.refcnt <= 1) {
1255 		if (cache_inval_vp_nonblock(vp))
1256 			return(0);
1257 		vgone_vxlocked(vp);
1258 		return (1);
1259 	}
1260 	return (0);
1261 }
1262 
1263 /*
1264  * Return the maximum I/O size allowed for strategy calls on VP.
1265  *
1266  * If vp is VCHR or VBLK we dive the device, otherwise we use
1267  * the vp's mount info.
1268  */
1269 int
1270 vmaxiosize(struct vnode *vp)
1271 {
1272 	if (vp->v_type == VBLK || vp->v_type == VCHR) {
1273 		return(vp->v_rdev->si_iosize_max);
1274 	} else {
1275 		return(vp->v_mount->mnt_iosize_max);
1276 	}
1277 }
1278 
1279 /*
1280  * Eliminate all activity associated with a vnode in preparation for reuse.
1281  *
1282  * The vnode must be VX locked and refd and will remain VX locked and refd
1283  * on return.  This routine may be called with the vnode in any state, as
1284  * long as it is VX locked.  The vnode will be cleaned out and marked
1285  * VRECLAIMED but will not actually be reused until all existing refs and
1286  * holds go away.
1287  *
1288  * NOTE: This routine may be called on a vnode which has not yet been
1289  * already been deactivated (VOP_INACTIVE), or on a vnode which has
1290  * already been reclaimed.
1291  *
1292  * This routine is not responsible for placing us back on the freelist.
1293  * Instead, it happens automatically when the caller releases the VX lock
1294  * (assuming there aren't any other references).
1295  */
1296 
1297 void
1298 vgone_vxlocked(struct vnode *vp)
1299 {
1300 	/*
1301 	 * assert that the VX lock is held.  This is an absolute requirement
1302 	 * now for vgone_vxlocked() to be called.
1303 	 */
1304 	KKASSERT(vp->v_lock.lk_exclusivecount == 1);
1305 
1306 	/*
1307 	 * Clean out the filesystem specific data and set the VRECLAIMED
1308 	 * bit.  Also deactivate the vnode if necessary.
1309 	 */
1310 	vclean_vxlocked(vp, DOCLOSE);
1311 
1312 	/*
1313 	 * Delete from old mount point vnode list, if on one.
1314 	 */
1315 	if (vp->v_mount != NULL)
1316 		insmntque(vp, NULL);
1317 
1318 	/*
1319 	 * If special device, remove it from special device alias list
1320 	 * if it is on one.  This should normally only occur if a vnode is
1321 	 * being revoked as the device should otherwise have been released
1322 	 * naturally.
1323 	 */
1324 	if ((vp->v_type == VBLK || vp->v_type == VCHR) && vp->v_rdev != NULL) {
1325 		v_release_rdev(vp);
1326 	}
1327 
1328 	/*
1329 	 * Set us to VBAD
1330 	 */
1331 	vp->v_type = VBAD;
1332 }
1333 
1334 /*
1335  * Lookup a vnode by device number.
1336  *
1337  * Returns non-zero and *vpp set to a vref'd vnode on success.
1338  * Returns zero on failure.
1339  */
1340 int
1341 vfinddev(cdev_t dev, enum vtype type, struct vnode **vpp)
1342 {
1343 	lwkt_tokref ilock;
1344 	struct vnode *vp;
1345 
1346 	lwkt_gettoken(&ilock, &spechash_token);
1347 	SLIST_FOREACH(vp, &dev->si_hlist, v_cdevnext) {
1348 		if (type == vp->v_type) {
1349 			*vpp = vp;
1350 			vref(vp);
1351 			lwkt_reltoken(&ilock);
1352 			return (1);
1353 		}
1354 	}
1355 	lwkt_reltoken(&ilock);
1356 	return (0);
1357 }
1358 
1359 /*
1360  * Calculate the total number of references to a special device.  This
1361  * routine may only be called for VBLK and VCHR vnodes since v_rdev is
1362  * an overloaded field.  Since udev2dev can now return NULL, we have
1363  * to check for a NULL v_rdev.
1364  */
1365 int
1366 count_dev(cdev_t dev)
1367 {
1368 	lwkt_tokref ilock;
1369 	struct vnode *vp;
1370 	int count = 0;
1371 
1372 	if (SLIST_FIRST(&dev->si_hlist)) {
1373 		lwkt_gettoken(&ilock, &spechash_token);
1374 		SLIST_FOREACH(vp, &dev->si_hlist, v_cdevnext) {
1375 			if (vp->v_sysref.refcnt > 0)
1376 				count += vp->v_sysref.refcnt;
1377 		}
1378 		lwkt_reltoken(&ilock);
1379 	}
1380 	return(count);
1381 }
1382 
1383 int
1384 count_udev(int x, int y)
1385 {
1386 	cdev_t dev;
1387 
1388 	if ((dev = get_dev(x, y)) == NULL)
1389 		return(0);
1390 	return(count_dev(dev));
1391 }
1392 
1393 int
1394 vcount(struct vnode *vp)
1395 {
1396 	if (vp->v_rdev == NULL)
1397 		return(0);
1398 	return(count_dev(vp->v_rdev));
1399 }
1400 
1401 /*
1402  * Initialize VMIO for a vnode.  This routine MUST be called before a
1403  * VFS can issue buffer cache ops on a vnode.  It is typically called
1404  * when a vnode is initialized from its inode.
1405  */
1406 int
1407 vinitvmio(struct vnode *vp, off_t filesize)
1408 {
1409 	vm_object_t object;
1410 	int error = 0;
1411 
1412 retry:
1413 	if ((object = vp->v_object) == NULL) {
1414 		object = vnode_pager_alloc(vp, filesize, 0, 0);
1415 		/*
1416 		 * Dereference the reference we just created.  This assumes
1417 		 * that the object is associated with the vp.
1418 		 */
1419 		object->ref_count--;
1420 		vrele(vp);
1421 	} else {
1422 		if (object->flags & OBJ_DEAD) {
1423 			vn_unlock(vp);
1424 			vm_object_dead_sleep(object, "vodead");
1425 			vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1426 			goto retry;
1427 		}
1428 	}
1429 	KASSERT(vp->v_object != NULL, ("vinitvmio: NULL object"));
1430 	vp->v_flag |= VOBJBUF;
1431 	return (error);
1432 }
1433 
1434 
1435 /*
1436  * Print out a description of a vnode.
1437  */
1438 static char *typename[] =
1439 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
1440 
1441 void
1442 vprint(char *label, struct vnode *vp)
1443 {
1444 	char buf[96];
1445 
1446 	if (label != NULL)
1447 		kprintf("%s: %p: ", label, (void *)vp);
1448 	else
1449 		kprintf("%p: ", (void *)vp);
1450 	kprintf("type %s, sysrefs %d, writecount %d, holdcnt %d,",
1451 		typename[vp->v_type],
1452 		vp->v_sysref.refcnt, vp->v_writecount, vp->v_auxrefs);
1453 	buf[0] = '\0';
1454 	if (vp->v_flag & VROOT)
1455 		strcat(buf, "|VROOT");
1456 	if (vp->v_flag & VPFSROOT)
1457 		strcat(buf, "|VPFSROOT");
1458 	if (vp->v_flag & VTEXT)
1459 		strcat(buf, "|VTEXT");
1460 	if (vp->v_flag & VSYSTEM)
1461 		strcat(buf, "|VSYSTEM");
1462 	if (vp->v_flag & VFREE)
1463 		strcat(buf, "|VFREE");
1464 	if (vp->v_flag & VOBJBUF)
1465 		strcat(buf, "|VOBJBUF");
1466 	if (buf[0] != '\0')
1467 		kprintf(" flags (%s)", &buf[1]);
1468 	if (vp->v_data == NULL) {
1469 		kprintf("\n");
1470 	} else {
1471 		kprintf("\n\t");
1472 		VOP_PRINT(vp);
1473 	}
1474 }
1475 
1476 #ifdef DDB
1477 #include <ddb/ddb.h>
1478 
1479 static int db_show_locked_vnodes(struct mount *mp, void *data);
1480 
1481 /*
1482  * List all of the locked vnodes in the system.
1483  * Called when debugging the kernel.
1484  */
1485 DB_SHOW_COMMAND(lockedvnodes, lockedvnodes)
1486 {
1487 	kprintf("Locked vnodes\n");
1488 	mountlist_scan(db_show_locked_vnodes, NULL,
1489 			MNTSCAN_FORWARD|MNTSCAN_NOBUSY);
1490 }
1491 
1492 static int
1493 db_show_locked_vnodes(struct mount *mp, void *data __unused)
1494 {
1495 	struct vnode *vp;
1496 
1497 	TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
1498 		if (vn_islocked(vp))
1499 			vprint(NULL, vp);
1500 	}
1501 	return(0);
1502 }
1503 #endif
1504 
1505 /*
1506  * Top level filesystem related information gathering.
1507  */
1508 static int	sysctl_ovfs_conf (SYSCTL_HANDLER_ARGS);
1509 
1510 static int
1511 vfs_sysctl(SYSCTL_HANDLER_ARGS)
1512 {
1513 	int *name = (int *)arg1 - 1;	/* XXX */
1514 	u_int namelen = arg2 + 1;	/* XXX */
1515 	struct vfsconf *vfsp;
1516 	int maxtypenum;
1517 
1518 #if 1 || defined(COMPAT_PRELITE2)
1519 	/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
1520 	if (namelen == 1)
1521 		return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
1522 #endif
1523 
1524 #ifdef notyet
1525 	/* all sysctl names at this level are at least name and field */
1526 	if (namelen < 2)
1527 		return (ENOTDIR);		/* overloaded */
1528 	if (name[0] != VFS_GENERIC) {
1529 		vfsp = vfsconf_find_by_typenum(name[0]);
1530 		if (vfsp == NULL)
1531 			return (EOPNOTSUPP);
1532 		return ((*vfsp->vfc_vfsops->vfs_sysctl)(&name[1], namelen - 1,
1533 		    oldp, oldlenp, newp, newlen, p));
1534 	}
1535 #endif
1536 	switch (name[1]) {
1537 	case VFS_MAXTYPENUM:
1538 		if (namelen != 2)
1539 			return (ENOTDIR);
1540 		maxtypenum = vfsconf_get_maxtypenum();
1541 		return (SYSCTL_OUT(req, &maxtypenum, sizeof(maxtypenum)));
1542 	case VFS_CONF:
1543 		if (namelen != 3)
1544 			return (ENOTDIR);	/* overloaded */
1545 		vfsp = vfsconf_find_by_typenum(name[2]);
1546 		if (vfsp == NULL)
1547 			return (EOPNOTSUPP);
1548 		return (SYSCTL_OUT(req, vfsp, sizeof *vfsp));
1549 	}
1550 	return (EOPNOTSUPP);
1551 }
1552 
1553 SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD, vfs_sysctl,
1554 	"Generic filesystem");
1555 
1556 #if 1 || defined(COMPAT_PRELITE2)
1557 
1558 static int
1559 sysctl_ovfs_conf_iter(struct vfsconf *vfsp, void *data)
1560 {
1561 	int error;
1562 	struct ovfsconf ovfs;
1563 	struct sysctl_req *req = (struct sysctl_req*) data;
1564 
1565 	bzero(&ovfs, sizeof(ovfs));
1566 	ovfs.vfc_vfsops = vfsp->vfc_vfsops;	/* XXX used as flag */
1567 	strcpy(ovfs.vfc_name, vfsp->vfc_name);
1568 	ovfs.vfc_index = vfsp->vfc_typenum;
1569 	ovfs.vfc_refcount = vfsp->vfc_refcount;
1570 	ovfs.vfc_flags = vfsp->vfc_flags;
1571 	error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
1572 	if (error)
1573 		return error; /* abort iteration with error code */
1574 	else
1575 		return 0; /* continue iterating with next element */
1576 }
1577 
1578 static int
1579 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
1580 {
1581 	return vfsconf_each(sysctl_ovfs_conf_iter, (void*)req);
1582 }
1583 
1584 #endif /* 1 || COMPAT_PRELITE2 */
1585 
1586 /*
1587  * Check to see if a filesystem is mounted on a block device.
1588  */
1589 int
1590 vfs_mountedon(struct vnode *vp)
1591 {
1592 	cdev_t dev;
1593 
1594 	if ((dev = vp->v_rdev) == NULL) {
1595 		if (vp->v_type != VBLK)
1596 			dev = get_dev(vp->v_uminor, vp->v_umajor);
1597 	}
1598 	if (dev != NULL && dev->si_mountpoint)
1599 		return (EBUSY);
1600 	return (0);
1601 }
1602 
1603 /*
1604  * Unmount all filesystems. The list is traversed in reverse order
1605  * of mounting to avoid dependencies.
1606  */
1607 
1608 static int vfs_umountall_callback(struct mount *mp, void *data);
1609 
1610 void
1611 vfs_unmountall(void)
1612 {
1613 	int count;
1614 
1615 	do {
1616 		count = mountlist_scan(vfs_umountall_callback,
1617 					NULL, MNTSCAN_REVERSE|MNTSCAN_NOBUSY);
1618 	} while (count);
1619 }
1620 
1621 static
1622 int
1623 vfs_umountall_callback(struct mount *mp, void *data)
1624 {
1625 	int error;
1626 
1627 	error = dounmount(mp, MNT_FORCE);
1628 	if (error) {
1629 		mountlist_remove(mp);
1630 		kprintf("unmount of filesystem mounted from %s failed (",
1631 			mp->mnt_stat.f_mntfromname);
1632 		if (error == EBUSY)
1633 			kprintf("BUSY)\n");
1634 		else
1635 			kprintf("%d)\n", error);
1636 	}
1637 	return(1);
1638 }
1639 
1640 /*
1641  * Build hash lists of net addresses and hang them off the mount point.
1642  * Called by ufs_mount() to set up the lists of export addresses.
1643  */
1644 static int
1645 vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
1646 		const struct export_args *argp)
1647 {
1648 	struct netcred *np;
1649 	struct radix_node_head *rnh;
1650 	int i;
1651 	struct radix_node *rn;
1652 	struct sockaddr *saddr, *smask = 0;
1653 	struct domain *dom;
1654 	int error;
1655 
1656 	if (argp->ex_addrlen == 0) {
1657 		if (mp->mnt_flag & MNT_DEFEXPORTED)
1658 			return (EPERM);
1659 		np = &nep->ne_defexported;
1660 		np->netc_exflags = argp->ex_flags;
1661 		np->netc_anon = argp->ex_anon;
1662 		np->netc_anon.cr_ref = 1;
1663 		mp->mnt_flag |= MNT_DEFEXPORTED;
1664 		return (0);
1665 	}
1666 
1667 	if (argp->ex_addrlen < 0 || argp->ex_addrlen > MLEN)
1668 		return (EINVAL);
1669 	if (argp->ex_masklen < 0 || argp->ex_masklen > MLEN)
1670 		return (EINVAL);
1671 
1672 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
1673 	np = (struct netcred *) kmalloc(i, M_NETADDR, M_WAITOK | M_ZERO);
1674 	saddr = (struct sockaddr *) (np + 1);
1675 	if ((error = copyin(argp->ex_addr, (caddr_t) saddr, argp->ex_addrlen)))
1676 		goto out;
1677 	if (saddr->sa_len > argp->ex_addrlen)
1678 		saddr->sa_len = argp->ex_addrlen;
1679 	if (argp->ex_masklen) {
1680 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
1681 		error = copyin(argp->ex_mask, (caddr_t)smask, argp->ex_masklen);
1682 		if (error)
1683 			goto out;
1684 		if (smask->sa_len > argp->ex_masklen)
1685 			smask->sa_len = argp->ex_masklen;
1686 	}
1687 	i = saddr->sa_family;
1688 	if ((rnh = nep->ne_rtable[i]) == 0) {
1689 		/*
1690 		 * Seems silly to initialize every AF when most are not used,
1691 		 * do so on demand here
1692 		 */
1693 		SLIST_FOREACH(dom, &domains, dom_next)
1694 			if (dom->dom_family == i && dom->dom_rtattach) {
1695 				dom->dom_rtattach((void **) &nep->ne_rtable[i],
1696 				    dom->dom_rtoffset);
1697 				break;
1698 			}
1699 		if ((rnh = nep->ne_rtable[i]) == 0) {
1700 			error = ENOBUFS;
1701 			goto out;
1702 		}
1703 	}
1704 	rn = (*rnh->rnh_addaddr) ((char *) saddr, (char *) smask, rnh,
1705 	    np->netc_rnodes);
1706 	if (rn == 0 || np != (struct netcred *) rn) {	/* already exists */
1707 		error = EPERM;
1708 		goto out;
1709 	}
1710 	np->netc_exflags = argp->ex_flags;
1711 	np->netc_anon = argp->ex_anon;
1712 	np->netc_anon.cr_ref = 1;
1713 	return (0);
1714 out:
1715 	kfree(np, M_NETADDR);
1716 	return (error);
1717 }
1718 
1719 /* ARGSUSED */
1720 static int
1721 vfs_free_netcred(struct radix_node *rn, void *w)
1722 {
1723 	struct radix_node_head *rnh = (struct radix_node_head *) w;
1724 
1725 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
1726 	kfree((caddr_t) rn, M_NETADDR);
1727 	return (0);
1728 }
1729 
1730 /*
1731  * Free the net address hash lists that are hanging off the mount points.
1732  */
1733 static void
1734 vfs_free_addrlist(struct netexport *nep)
1735 {
1736 	int i;
1737 	struct radix_node_head *rnh;
1738 
1739 	for (i = 0; i <= AF_MAX; i++)
1740 		if ((rnh = nep->ne_rtable[i])) {
1741 			(*rnh->rnh_walktree) (rnh, vfs_free_netcred,
1742 			    (caddr_t) rnh);
1743 			kfree((caddr_t) rnh, M_RTABLE);
1744 			nep->ne_rtable[i] = 0;
1745 		}
1746 }
1747 
1748 int
1749 vfs_export(struct mount *mp, struct netexport *nep,
1750 	   const struct export_args *argp)
1751 {
1752 	int error;
1753 
1754 	if (argp->ex_flags & MNT_DELEXPORT) {
1755 		if (mp->mnt_flag & MNT_EXPUBLIC) {
1756 			vfs_setpublicfs(NULL, NULL, NULL);
1757 			mp->mnt_flag &= ~MNT_EXPUBLIC;
1758 		}
1759 		vfs_free_addrlist(nep);
1760 		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
1761 	}
1762 	if (argp->ex_flags & MNT_EXPORTED) {
1763 		if (argp->ex_flags & MNT_EXPUBLIC) {
1764 			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
1765 				return (error);
1766 			mp->mnt_flag |= MNT_EXPUBLIC;
1767 		}
1768 		if ((error = vfs_hang_addrlist(mp, nep, argp)))
1769 			return (error);
1770 		mp->mnt_flag |= MNT_EXPORTED;
1771 	}
1772 	return (0);
1773 }
1774 
1775 
1776 /*
1777  * Set the publicly exported filesystem (WebNFS). Currently, only
1778  * one public filesystem is possible in the spec (RFC 2054 and 2055)
1779  */
1780 int
1781 vfs_setpublicfs(struct mount *mp, struct netexport *nep,
1782 		const struct export_args *argp)
1783 {
1784 	int error;
1785 	struct vnode *rvp;
1786 	char *cp;
1787 
1788 	/*
1789 	 * mp == NULL -> invalidate the current info, the FS is
1790 	 * no longer exported. May be called from either vfs_export
1791 	 * or unmount, so check if it hasn't already been done.
1792 	 */
1793 	if (mp == NULL) {
1794 		if (nfs_pub.np_valid) {
1795 			nfs_pub.np_valid = 0;
1796 			if (nfs_pub.np_index != NULL) {
1797 				FREE(nfs_pub.np_index, M_TEMP);
1798 				nfs_pub.np_index = NULL;
1799 			}
1800 		}
1801 		return (0);
1802 	}
1803 
1804 	/*
1805 	 * Only one allowed at a time.
1806 	 */
1807 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
1808 		return (EBUSY);
1809 
1810 	/*
1811 	 * Get real filehandle for root of exported FS.
1812 	 */
1813 	bzero((caddr_t)&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
1814 	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
1815 
1816 	if ((error = VFS_ROOT(mp, &rvp)))
1817 		return (error);
1818 
1819 	if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
1820 		return (error);
1821 
1822 	vput(rvp);
1823 
1824 	/*
1825 	 * If an indexfile was specified, pull it in.
1826 	 */
1827 	if (argp->ex_indexfile != NULL) {
1828 		int namelen;
1829 
1830 		error = vn_get_namelen(rvp, &namelen);
1831 		if (error)
1832 			return (error);
1833 		MALLOC(nfs_pub.np_index, char *, namelen, M_TEMP,
1834 		    M_WAITOK);
1835 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
1836 		    namelen, NULL);
1837 		if (!error) {
1838 			/*
1839 			 * Check for illegal filenames.
1840 			 */
1841 			for (cp = nfs_pub.np_index; *cp; cp++) {
1842 				if (*cp == '/') {
1843 					error = EINVAL;
1844 					break;
1845 				}
1846 			}
1847 		}
1848 		if (error) {
1849 			FREE(nfs_pub.np_index, M_TEMP);
1850 			return (error);
1851 		}
1852 	}
1853 
1854 	nfs_pub.np_mount = mp;
1855 	nfs_pub.np_valid = 1;
1856 	return (0);
1857 }
1858 
1859 struct netcred *
1860 vfs_export_lookup(struct mount *mp, struct netexport *nep,
1861 		struct sockaddr *nam)
1862 {
1863 	struct netcred *np;
1864 	struct radix_node_head *rnh;
1865 	struct sockaddr *saddr;
1866 
1867 	np = NULL;
1868 	if (mp->mnt_flag & MNT_EXPORTED) {
1869 		/*
1870 		 * Lookup in the export list first.
1871 		 */
1872 		if (nam != NULL) {
1873 			saddr = nam;
1874 			rnh = nep->ne_rtable[saddr->sa_family];
1875 			if (rnh != NULL) {
1876 				np = (struct netcred *)
1877 					(*rnh->rnh_matchaddr)((char *)saddr,
1878 							      rnh);
1879 				if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
1880 					np = NULL;
1881 			}
1882 		}
1883 		/*
1884 		 * If no address match, use the default if it exists.
1885 		 */
1886 		if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
1887 			np = &nep->ne_defexported;
1888 	}
1889 	return (np);
1890 }
1891 
1892 /*
1893  * perform msync on all vnodes under a mount point.  The mount point must
1894  * be locked.  This code is also responsible for lazy-freeing unreferenced
1895  * vnodes whos VM objects no longer contain pages.
1896  *
1897  * NOTE: MNT_WAIT still skips vnodes in the VXLOCK state.
1898  *
1899  * NOTE: XXX VOP_PUTPAGES and friends requires that the vnode be locked,
1900  * but vnode_pager_putpages() doesn't lock the vnode.  We have to do it
1901  * way up in this high level function.
1902  */
1903 static int vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data);
1904 static int vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data);
1905 
1906 void
1907 vfs_msync(struct mount *mp, int flags)
1908 {
1909 	int vmsc_flags;
1910 
1911 	vmsc_flags = VMSC_GETVP;
1912 	if (flags != MNT_WAIT)
1913 		vmsc_flags |= VMSC_NOWAIT;
1914 	vmntvnodescan(mp, vmsc_flags, vfs_msync_scan1, vfs_msync_scan2,
1915 			(void *)flags);
1916 }
1917 
1918 /*
1919  * scan1 is a fast pre-check.  There could be hundreds of thousands of
1920  * vnodes, we cannot afford to do anything heavy weight until we have a
1921  * fairly good indication that there is work to do.
1922  */
1923 static
1924 int
1925 vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data)
1926 {
1927 	int flags = (int)data;
1928 
1929 	if ((vp->v_flag & VRECLAIMED) == 0) {
1930 		if (vshouldmsync(vp))
1931 			return(0);	/* call scan2 */
1932 		if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
1933 		    (vp->v_flag & VOBJDIRTY) &&
1934 		    (flags == MNT_WAIT || vn_islocked(vp) == 0)) {
1935 			return(0);	/* call scan2 */
1936 		}
1937 	}
1938 
1939 	/*
1940 	 * do not call scan2, continue the loop
1941 	 */
1942 	return(-1);
1943 }
1944 
1945 /*
1946  * This callback is handed a locked vnode.
1947  */
1948 static
1949 int
1950 vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data)
1951 {
1952 	vm_object_t obj;
1953 	int flags = (int)data;
1954 
1955 	if (vp->v_flag & VRECLAIMED)
1956 		return(0);
1957 
1958 	if ((mp->mnt_flag & MNT_RDONLY) == 0 && (vp->v_flag & VOBJDIRTY)) {
1959 		if ((obj = vp->v_object) != NULL) {
1960 			vm_object_page_clean(obj, 0, 0,
1961 			 flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
1962 		}
1963 	}
1964 	return(0);
1965 }
1966 
1967 /*
1968  * Record a process's interest in events which might happen to
1969  * a vnode.  Because poll uses the historic select-style interface
1970  * internally, this routine serves as both the ``check for any
1971  * pending events'' and the ``record my interest in future events''
1972  * functions.  (These are done together, while the lock is held,
1973  * to avoid race conditions.)
1974  */
1975 int
1976 vn_pollrecord(struct vnode *vp, int events)
1977 {
1978 	lwkt_tokref ilock;
1979 
1980 	KKASSERT(curthread->td_proc != NULL);
1981 
1982 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
1983 	if (vp->v_pollinfo.vpi_revents & events) {
1984 		/*
1985 		 * This leaves events we are not interested
1986 		 * in available for the other process which
1987 		 * which presumably had requested them
1988 		 * (otherwise they would never have been
1989 		 * recorded).
1990 		 */
1991 		events &= vp->v_pollinfo.vpi_revents;
1992 		vp->v_pollinfo.vpi_revents &= ~events;
1993 
1994 		lwkt_reltoken(&ilock);
1995 		return events;
1996 	}
1997 	vp->v_pollinfo.vpi_events |= events;
1998 	selrecord(curthread, &vp->v_pollinfo.vpi_selinfo);
1999 	lwkt_reltoken(&ilock);
2000 	return 0;
2001 }
2002 
2003 /*
2004  * Note the occurrence of an event.  If the VN_POLLEVENT macro is used,
2005  * it is possible for us to miss an event due to race conditions, but
2006  * that condition is expected to be rare, so for the moment it is the
2007  * preferred interface.
2008  */
2009 void
2010 vn_pollevent(struct vnode *vp, int events)
2011 {
2012 	lwkt_tokref ilock;
2013 
2014 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
2015 	if (vp->v_pollinfo.vpi_events & events) {
2016 		/*
2017 		 * We clear vpi_events so that we don't
2018 		 * call selwakeup() twice if two events are
2019 		 * posted before the polling process(es) is
2020 		 * awakened.  This also ensures that we take at
2021 		 * most one selwakeup() if the polling process
2022 		 * is no longer interested.  However, it does
2023 		 * mean that only one event can be noticed at
2024 		 * a time.  (Perhaps we should only clear those
2025 		 * event bits which we note?) XXX
2026 		 */
2027 		vp->v_pollinfo.vpi_events = 0;	/* &= ~events ??? */
2028 		vp->v_pollinfo.vpi_revents |= events;
2029 		selwakeup(&vp->v_pollinfo.vpi_selinfo);
2030 	}
2031 	lwkt_reltoken(&ilock);
2032 }
2033 
2034 /*
2035  * Wake up anyone polling on vp because it is being revoked.
2036  * This depends on dead_poll() returning POLLHUP for correct
2037  * behavior.
2038  */
2039 void
2040 vn_pollgone(struct vnode *vp)
2041 {
2042 	lwkt_tokref ilock;
2043 
2044 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
2045 	if (vp->v_pollinfo.vpi_events) {
2046 		vp->v_pollinfo.vpi_events = 0;
2047 		selwakeup(&vp->v_pollinfo.vpi_selinfo);
2048 	}
2049 	lwkt_reltoken(&ilock);
2050 }
2051 
2052 /*
2053  * extract the cdev_t from a VBLK or VCHR.  The vnode must have been opened
2054  * (or v_rdev might be NULL).
2055  */
2056 cdev_t
2057 vn_todev(struct vnode *vp)
2058 {
2059 	if (vp->v_type != VBLK && vp->v_type != VCHR)
2060 		return (NULL);
2061 	KKASSERT(vp->v_rdev != NULL);
2062 	return (vp->v_rdev);
2063 }
2064 
2065 /*
2066  * Check if vnode represents a disk device.  The vnode does not need to be
2067  * opened.
2068  */
2069 int
2070 vn_isdisk(struct vnode *vp, int *errp)
2071 {
2072 	cdev_t dev;
2073 
2074 	if (vp->v_type != VCHR) {
2075 		if (errp != NULL)
2076 			*errp = ENOTBLK;
2077 		return (0);
2078 	}
2079 
2080 	if ((dev = vp->v_rdev) == NULL)
2081 		dev = get_dev(vp->v_umajor, vp->v_uminor);
2082 
2083 	if (dev == NULL) {
2084 		if (errp != NULL)
2085 			*errp = ENXIO;
2086 		return (0);
2087 	}
2088 	if (dev_is_good(dev) == 0) {
2089 		if (errp != NULL)
2090 			*errp = ENXIO;
2091 		return (0);
2092 	}
2093 	if ((dev_dflags(dev) & D_DISK) == 0) {
2094 		if (errp != NULL)
2095 			*errp = ENOTBLK;
2096 		return (0);
2097 	}
2098 	if (errp != NULL)
2099 		*errp = 0;
2100 	return (1);
2101 }
2102 
2103 int
2104 vn_get_namelen(struct vnode *vp, int *namelen)
2105 {
2106 	int error, retval[2];
2107 
2108 	error = VOP_PATHCONF(vp, _PC_NAME_MAX, retval);
2109 	if (error)
2110 		return (error);
2111 	*namelen = *retval;
2112 	return (0);
2113 }
2114 
2115 int
2116 vop_write_dirent(int *error, struct uio *uio, ino_t d_ino, uint8_t d_type,
2117 		uint16_t d_namlen, const char *d_name)
2118 {
2119 	struct dirent *dp;
2120 	size_t len;
2121 
2122 	len = _DIRENT_RECLEN(d_namlen);
2123 	if (len > uio->uio_resid)
2124 		return(1);
2125 
2126 	dp = kmalloc(len, M_TEMP, M_WAITOK | M_ZERO);
2127 
2128 	dp->d_ino = d_ino;
2129 	dp->d_namlen = d_namlen;
2130 	dp->d_type = d_type;
2131 	bcopy(d_name, dp->d_name, d_namlen);
2132 
2133 	*error = uiomove((caddr_t)dp, len, uio);
2134 
2135 	kfree(dp, M_TEMP);
2136 
2137 	return(0);
2138 }
2139 
2140 void
2141 vn_mark_atime(struct vnode *vp, struct thread *td)
2142 {
2143 	struct proc *p = td->td_proc;
2144 	struct ucred *cred = p ? p->p_ucred : proc0.p_ucred;
2145 
2146 	if ((vp->v_mount->mnt_flag & (MNT_NOATIME | MNT_RDONLY)) == 0) {
2147 		VOP_MARKATIME(vp, cred);
2148 	}
2149 }
2150