xref: /dragonfly/sys/kern/vfs_subr.c (revision 6ab64ab6)
1 /*
2  * Copyright (c) 1989, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  * (c) UNIX System Laboratories, Inc.
5  * All or some portions of this file are derived from material licensed
6  * to the University of California by American Telephone and Telegraph
7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
8  * the permission of UNIX System Laboratories, Inc.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  *	@(#)vfs_subr.c	8.31 (Berkeley) 5/26/95
35  * $FreeBSD: src/sys/kern/vfs_subr.c,v 1.249.2.30 2003/04/04 20:35:57 tegge Exp $
36  */
37 
38 /*
39  * External virtual filesystem routines
40  */
41 #include "opt_ddb.h"
42 #include "opt_inet.h"
43 #include "opt_inet6.h"
44 
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/buf.h>
48 #include <sys/conf.h>
49 #include <sys/dirent.h>
50 #include <sys/eventhandler.h>
51 #include <sys/fcntl.h>
52 #include <sys/file.h>
53 #include <sys/kernel.h>
54 #include <sys/kthread.h>
55 #include <sys/malloc.h>
56 #include <sys/mbuf.h>
57 #include <sys/mount.h>
58 #include <sys/priv.h>
59 #include <sys/proc.h>
60 #include <sys/reboot.h>
61 #include <sys/socket.h>
62 #include <sys/stat.h>
63 #include <sys/sysctl.h>
64 #include <sys/syslog.h>
65 #include <sys/unistd.h>
66 #include <sys/vmmeter.h>
67 #include <sys/vnode.h>
68 
69 #include <machine/limits.h>
70 
71 #include <vm/vm.h>
72 #include <vm/vm_object.h>
73 #include <vm/vm_extern.h>
74 #include <vm/vm_kern.h>
75 #include <vm/pmap.h>
76 #include <vm/vm_map.h>
77 #include <vm/vm_page.h>
78 #include <vm/vm_pager.h>
79 #include <vm/vnode_pager.h>
80 #include <vm/vm_zone.h>
81 
82 #include <sys/buf2.h>
83 #include <sys/thread2.h>
84 #include <sys/sysref2.h>
85 #include <sys/mplock2.h>
86 
87 #include <netinet/in.h>
88 
89 static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
90 
91 int numvnodes;
92 SYSCTL_INT(_debug, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0,
93     "Number of vnodes allocated");
94 int verbose_reclaims;
95 SYSCTL_INT(_debug, OID_AUTO, verbose_reclaims, CTLFLAG_RD, &verbose_reclaims, 0,
96     "Output filename of reclaimed vnode(s)");
97 
98 enum vtype iftovt_tab[16] = {
99 	VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
100 	VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VBAD,
101 };
102 int vttoif_tab[9] = {
103 	0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
104 	S_IFSOCK, S_IFIFO, S_IFMT,
105 };
106 
107 static int reassignbufcalls;
108 SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW, &reassignbufcalls,
109     0, "Number of times buffers have been reassigned to the proper list");
110 
111 static int check_buf_overlap = 2;	/* invasive check */
112 SYSCTL_INT(_vfs, OID_AUTO, check_buf_overlap, CTLFLAG_RW, &check_buf_overlap,
113     0, "Enable overlapping buffer checks");
114 
115 int	nfs_mount_type = -1;
116 static struct lwkt_token spechash_token;
117 struct nfs_public nfs_pub;	/* publicly exported FS */
118 
119 int maxvnodes;
120 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
121 	   &maxvnodes, 0, "Maximum number of vnodes");
122 
123 static struct radix_node_head *vfs_create_addrlist_af(int af,
124 		    struct netexport *nep);
125 static void	vfs_free_addrlist (struct netexport *nep);
126 static int	vfs_free_netcred (struct radix_node *rn, void *w);
127 static void	vfs_free_addrlist_af (struct radix_node_head **prnh);
128 static int	vfs_hang_addrlist (struct mount *mp, struct netexport *nep,
129 	            const struct export_args *argp);
130 
131 int	prtactive = 0;		/* 1 => print out reclaim of active vnodes */
132 
133 /*
134  * Red black tree functions
135  */
136 static int rb_buf_compare(struct buf *b1, struct buf *b2);
137 RB_GENERATE2(buf_rb_tree, buf, b_rbnode, rb_buf_compare, off_t, b_loffset);
138 RB_GENERATE2(buf_rb_hash, buf, b_rbhash, rb_buf_compare, off_t, b_loffset);
139 
140 static int
141 rb_buf_compare(struct buf *b1, struct buf *b2)
142 {
143 	if (b1->b_loffset < b2->b_loffset)
144 		return(-1);
145 	if (b1->b_loffset > b2->b_loffset)
146 		return(1);
147 	return(0);
148 }
149 
150 /*
151  * Initialize the vnode management data structures.
152  *
153  * Called from vfsinit()
154  */
155 void
156 vfs_subr_init(void)
157 {
158 	int factor1;
159 	int factor2;
160 
161 	/*
162 	 * Desiredvnodes is kern.maxvnodes.  We want to scale it
163 	 * according to available system memory but we may also have
164 	 * to limit it based on available KVM, which is capped on 32 bit
165 	 * systems, to ~80K vnodes or so.
166 	 *
167 	 * WARNING!  For machines with 64-256M of ram we have to be sure
168 	 *	     that the default limit scales down well due to HAMMER
169 	 *	     taking up significantly more memory per-vnode vs UFS.
170 	 *	     We want around ~5800 on a 128M machine.
171 	 */
172 	factor1 = 25 * (sizeof(struct vm_object) + sizeof(struct vnode));
173 	factor2 = 30 * (sizeof(struct vm_object) + sizeof(struct vnode));
174 	maxvnodes = imin((int64_t)vmstats.v_page_count * PAGE_SIZE / factor1,
175 			 KvaSize / factor2);
176 	maxvnodes = imax(maxvnodes, maxproc * 8);
177 
178 	lwkt_token_init(&spechash_token, "spechash");
179 }
180 
181 /*
182  * Knob to control the precision of file timestamps:
183  *
184  *   0 = seconds only; nanoseconds zeroed.
185  *   1 = seconds and nanoseconds, accurate within 1/HZ.
186  *   2 = seconds and nanoseconds, truncated to microseconds.
187  * >=3 = seconds and nanoseconds, maximum precision.
188  */
189 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
190 
191 static int timestamp_precision = TSP_SEC;
192 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
193 		&timestamp_precision, 0, "Precision of file timestamps");
194 
195 /*
196  * Get a current timestamp.
197  *
198  * MPSAFE
199  */
200 void
201 vfs_timestamp(struct timespec *tsp)
202 {
203 	struct timeval tv;
204 
205 	switch (timestamp_precision) {
206 	case TSP_SEC:
207 		tsp->tv_sec = time_second;
208 		tsp->tv_nsec = 0;
209 		break;
210 	case TSP_HZ:
211 		getnanotime(tsp);
212 		break;
213 	case TSP_USEC:
214 		microtime(&tv);
215 		TIMEVAL_TO_TIMESPEC(&tv, tsp);
216 		break;
217 	case TSP_NSEC:
218 	default:
219 		nanotime(tsp);
220 		break;
221 	}
222 }
223 
224 /*
225  * Set vnode attributes to VNOVAL
226  */
227 void
228 vattr_null(struct vattr *vap)
229 {
230 	vap->va_type = VNON;
231 	vap->va_size = VNOVAL;
232 	vap->va_bytes = VNOVAL;
233 	vap->va_mode = VNOVAL;
234 	vap->va_nlink = VNOVAL;
235 	vap->va_uid = VNOVAL;
236 	vap->va_gid = VNOVAL;
237 	vap->va_fsid = VNOVAL;
238 	vap->va_fileid = VNOVAL;
239 	vap->va_blocksize = VNOVAL;
240 	vap->va_rmajor = VNOVAL;
241 	vap->va_rminor = VNOVAL;
242 	vap->va_atime.tv_sec = VNOVAL;
243 	vap->va_atime.tv_nsec = VNOVAL;
244 	vap->va_mtime.tv_sec = VNOVAL;
245 	vap->va_mtime.tv_nsec = VNOVAL;
246 	vap->va_ctime.tv_sec = VNOVAL;
247 	vap->va_ctime.tv_nsec = VNOVAL;
248 	vap->va_flags = VNOVAL;
249 	vap->va_gen = VNOVAL;
250 	vap->va_vaflags = 0;
251 	/* va_*_uuid fields are only valid if related flags are set */
252 }
253 
254 /*
255  * Flush out and invalidate all buffers associated with a vnode.
256  *
257  * vp must be locked.
258  */
259 static int vinvalbuf_bp(struct buf *bp, void *data);
260 
261 struct vinvalbuf_bp_info {
262 	struct vnode *vp;
263 	int slptimeo;
264 	int lkflags;
265 	int flags;
266 	int clean;
267 };
268 
269 int
270 vinvalbuf(struct vnode *vp, int flags, int slpflag, int slptimeo)
271 {
272 	struct vinvalbuf_bp_info info;
273 	vm_object_t object;
274 	int error;
275 
276 	lwkt_gettoken(&vp->v_token);
277 
278 	/*
279 	 * If we are being asked to save, call fsync to ensure that the inode
280 	 * is updated.
281 	 */
282 	if (flags & V_SAVE) {
283 		error = bio_track_wait(&vp->v_track_write, slpflag, slptimeo);
284 		if (error)
285 			goto done;
286 		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
287 			if ((error = VOP_FSYNC(vp, MNT_WAIT, 0)) != 0)
288 				goto done;
289 #if 0
290 			/*
291 			 * Dirty bufs may be left or generated via races
292 			 * in circumstances where vinvalbuf() is called on
293 			 * a vnode not undergoing reclamation.   Only
294 			 * panic if we are trying to reclaim the vnode.
295 			 */
296 			if ((vp->v_flag & VRECLAIMED) &&
297 			    (bio_track_active(&vp->v_track_write) ||
298 			    !RB_EMPTY(&vp->v_rbdirty_tree))) {
299 				panic("vinvalbuf: dirty bufs");
300 			}
301 #endif
302 		}
303   	}
304 	info.slptimeo = slptimeo;
305 	info.lkflags = LK_EXCLUSIVE | LK_SLEEPFAIL;
306 	if (slpflag & PCATCH)
307 		info.lkflags |= LK_PCATCH;
308 	info.flags = flags;
309 	info.vp = vp;
310 
311 	/*
312 	 * Flush the buffer cache until nothing is left, wait for all I/O
313 	 * to complete.  At least one pass is required.  We might block
314 	 * in the pip code so we have to re-check.  Order is important.
315 	 */
316 	do {
317 		/*
318 		 * Flush buffer cache
319 		 */
320 		if (!RB_EMPTY(&vp->v_rbclean_tree)) {
321 			info.clean = 1;
322 			error = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
323 					NULL, vinvalbuf_bp, &info);
324 		}
325 		if (!RB_EMPTY(&vp->v_rbdirty_tree)) {
326 			info.clean = 0;
327 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
328 					NULL, vinvalbuf_bp, &info);
329 		}
330 
331 		/*
332 		 * Wait for I/O completion.
333 		 */
334 		bio_track_wait(&vp->v_track_write, 0, 0);
335 		if ((object = vp->v_object) != NULL)
336 			refcount_wait(&object->paging_in_progress, "vnvlbx");
337 	} while (bio_track_active(&vp->v_track_write) ||
338 		 !RB_EMPTY(&vp->v_rbclean_tree) ||
339 		 !RB_EMPTY(&vp->v_rbdirty_tree));
340 
341 	/*
342 	 * Destroy the copy in the VM cache, too.
343 	 */
344 	if ((object = vp->v_object) != NULL) {
345 		vm_object_page_remove(object, 0, 0,
346 			(flags & V_SAVE) ? TRUE : FALSE);
347 	}
348 
349 	if (!RB_EMPTY(&vp->v_rbdirty_tree) || !RB_EMPTY(&vp->v_rbclean_tree))
350 		panic("vinvalbuf: flush failed");
351 	if (!RB_EMPTY(&vp->v_rbhash_tree))
352 		panic("vinvalbuf: flush failed, buffers still present");
353 	error = 0;
354 done:
355 	lwkt_reltoken(&vp->v_token);
356 	return (error);
357 }
358 
359 static int
360 vinvalbuf_bp(struct buf *bp, void *data)
361 {
362 	struct vinvalbuf_bp_info *info = data;
363 	int error;
364 
365 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
366 		atomic_add_int(&bp->b_refs, 1);
367 		error = BUF_TIMELOCK(bp, info->lkflags,
368 				     "vinvalbuf", info->slptimeo);
369 		atomic_subtract_int(&bp->b_refs, 1);
370 		if (error == 0) {
371 			BUF_UNLOCK(bp);
372 			error = ENOLCK;
373 		}
374 		if (error == ENOLCK)
375 			return(0);
376 		return (-error);
377 	}
378 	KKASSERT(bp->b_vp == info->vp);
379 
380 	/*
381 	 * Must check clean/dirty status after successfully locking as
382 	 * it may race.
383 	 */
384 	if ((info->clean && (bp->b_flags & B_DELWRI)) ||
385 	    (info->clean == 0 && (bp->b_flags & B_DELWRI) == 0)) {
386 		BUF_UNLOCK(bp);
387 		return(0);
388 	}
389 
390 	/*
391 	 * NOTE:  NO B_LOCKED CHECK.  Also no buf_checkwrite()
392 	 * check.  This code will write out the buffer, period.
393 	 */
394 	bremfree(bp);
395 	if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
396 	    (info->flags & V_SAVE)) {
397 		cluster_awrite(bp);
398 	} else if (info->flags & V_SAVE) {
399 		/*
400 		 * Cannot set B_NOCACHE on a clean buffer as this will
401 		 * destroy the VM backing store which might actually
402 		 * be dirty (and unsynchronized).
403 		 */
404 		bp->b_flags |= (B_INVAL | B_RELBUF);
405 		brelse(bp);
406 	} else {
407 		bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
408 		brelse(bp);
409 	}
410 	return(0);
411 }
412 
413 /*
414  * Truncate a file's buffer and pages to a specified length.  This
415  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
416  * sync activity.
417  *
418  * The vnode must be locked.
419  */
420 static int vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data);
421 static int vtruncbuf_bp_trunc(struct buf *bp, void *data);
422 static int vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data);
423 static int vtruncbuf_bp_metasync(struct buf *bp, void *data);
424 
425 struct vtruncbuf_info {
426 	struct vnode *vp;
427 	off_t	truncloffset;
428 	int	clean;
429 };
430 
431 int
432 vtruncbuf(struct vnode *vp, off_t length, int blksize)
433 {
434 	struct vtruncbuf_info info;
435 	const char *filename;
436 	int count;
437 
438 	/*
439 	 * Round up to the *next* block, then destroy the buffers in question.
440 	 * Since we are only removing some of the buffers we must rely on the
441 	 * scan count to determine whether a loop is necessary.
442 	 */
443 	if ((count = (int)(length % blksize)) != 0)
444 		info.truncloffset = length + (blksize - count);
445 	else
446 		info.truncloffset = length;
447 	info.vp = vp;
448 
449 	lwkt_gettoken(&vp->v_token);
450 	do {
451 		info.clean = 1;
452 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
453 				vtruncbuf_bp_trunc_cmp,
454 				vtruncbuf_bp_trunc, &info);
455 		info.clean = 0;
456 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
457 				vtruncbuf_bp_trunc_cmp,
458 				vtruncbuf_bp_trunc, &info);
459 	} while(count);
460 
461 	/*
462 	 * For safety, fsync any remaining metadata if the file is not being
463 	 * truncated to 0.  Since the metadata does not represent the entire
464 	 * dirty list we have to rely on the hit count to ensure that we get
465 	 * all of it.
466 	 */
467 	if (length > 0) {
468 		do {
469 			count = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
470 					vtruncbuf_bp_metasync_cmp,
471 					vtruncbuf_bp_metasync, &info);
472 		} while (count);
473 	}
474 
475 	/*
476 	 * Clean out any left over VM backing store.
477 	 *
478 	 * It is possible to have in-progress I/O from buffers that were
479 	 * not part of the truncation.  This should not happen if we
480 	 * are truncating to 0-length.
481 	 */
482 	vnode_pager_setsize(vp, length);
483 	bio_track_wait(&vp->v_track_write, 0, 0);
484 
485 	/*
486 	 * Debugging only
487 	 */
488 	spin_lock(&vp->v_spin);
489 	filename = TAILQ_FIRST(&vp->v_namecache) ?
490 		   TAILQ_FIRST(&vp->v_namecache)->nc_name : "?";
491 	spin_unlock(&vp->v_spin);
492 
493 	/*
494 	 * Make sure no buffers were instantiated while we were trying
495 	 * to clean out the remaining VM pages.  This could occur due
496 	 * to busy dirty VM pages being flushed out to disk.
497 	 */
498 	do {
499 		info.clean = 1;
500 		count = RB_SCAN(buf_rb_tree, &vp->v_rbclean_tree,
501 				vtruncbuf_bp_trunc_cmp,
502 				vtruncbuf_bp_trunc, &info);
503 		info.clean = 0;
504 		count += RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
505 				vtruncbuf_bp_trunc_cmp,
506 				vtruncbuf_bp_trunc, &info);
507 		if (count) {
508 			kprintf("Warning: vtruncbuf():  Had to re-clean %d "
509 			       "left over buffers in %s\n", count, filename);
510 		}
511 	} while(count);
512 
513 	lwkt_reltoken(&vp->v_token);
514 
515 	return (0);
516 }
517 
518 /*
519  * The callback buffer is beyond the new file EOF and must be destroyed.
520  * Note that the compare function must conform to the RB_SCAN's requirements.
521  */
522 static
523 int
524 vtruncbuf_bp_trunc_cmp(struct buf *bp, void *data)
525 {
526 	struct vtruncbuf_info *info = data;
527 
528 	if (bp->b_loffset >= info->truncloffset)
529 		return(0);
530 	return(-1);
531 }
532 
533 static
534 int
535 vtruncbuf_bp_trunc(struct buf *bp, void *data)
536 {
537 	struct vtruncbuf_info *info = data;
538 
539 	/*
540 	 * Do not try to use a buffer we cannot immediately lock, but sleep
541 	 * anyway to prevent a livelock.  The code will loop until all buffers
542 	 * can be acted upon.
543 	 *
544 	 * We must always revalidate the buffer after locking it to deal
545 	 * with MP races.
546 	 */
547 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
548 		atomic_add_int(&bp->b_refs, 1);
549 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
550 			BUF_UNLOCK(bp);
551 		atomic_subtract_int(&bp->b_refs, 1);
552 	} else if ((info->clean && (bp->b_flags & B_DELWRI)) ||
553 		   (info->clean == 0 && (bp->b_flags & B_DELWRI) == 0) ||
554 		   bp->b_vp != info->vp ||
555 		   vtruncbuf_bp_trunc_cmp(bp, data)) {
556 		BUF_UNLOCK(bp);
557 	} else {
558 		bremfree(bp);
559 		bp->b_flags |= (B_INVAL | B_RELBUF | B_NOCACHE);
560 		brelse(bp);
561 	}
562 	return(1);
563 }
564 
565 /*
566  * Fsync all meta-data after truncating a file to be non-zero.  Only metadata
567  * blocks (with a negative loffset) are scanned.
568  * Note that the compare function must conform to the RB_SCAN's requirements.
569  */
570 static int
571 vtruncbuf_bp_metasync_cmp(struct buf *bp, void *data __unused)
572 {
573 	if (bp->b_loffset < 0)
574 		return(0);
575 	return(1);
576 }
577 
578 static int
579 vtruncbuf_bp_metasync(struct buf *bp, void *data)
580 {
581 	struct vtruncbuf_info *info = data;
582 
583 	if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
584 		atomic_add_int(&bp->b_refs, 1);
585 		if (BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL) == 0)
586 			BUF_UNLOCK(bp);
587 		atomic_subtract_int(&bp->b_refs, 1);
588 	} else if ((bp->b_flags & B_DELWRI) == 0 ||
589 		   bp->b_vp != info->vp ||
590 		   vtruncbuf_bp_metasync_cmp(bp, data)) {
591 		BUF_UNLOCK(bp);
592 	} else {
593 		bremfree(bp);
594 		if (bp->b_vp == info->vp)
595 			bawrite(bp);
596 		else
597 			bwrite(bp);
598 	}
599 	return(1);
600 }
601 
602 /*
603  * vfsync - implements a multipass fsync on a file which understands
604  * dependancies and meta-data.  The passed vnode must be locked.  The
605  * waitfor argument may be MNT_WAIT or MNT_NOWAIT, or MNT_LAZY.
606  *
607  * When fsyncing data asynchronously just do one consolidated pass starting
608  * with the most negative block number.  This may not get all the data due
609  * to dependancies.
610  *
611  * When fsyncing data synchronously do a data pass, then a metadata pass,
612  * then do additional data+metadata passes to try to get all the data out.
613  *
614  * Caller must ref the vnode but does not have to lock it.
615  */
616 static int vfsync_wait_output(struct vnode *vp,
617 			    int (*waitoutput)(struct vnode *, struct thread *));
618 static int vfsync_dummy_cmp(struct buf *bp __unused, void *data __unused);
619 static int vfsync_data_only_cmp(struct buf *bp, void *data);
620 static int vfsync_meta_only_cmp(struct buf *bp, void *data);
621 static int vfsync_lazy_range_cmp(struct buf *bp, void *data);
622 static int vfsync_bp(struct buf *bp, void *data);
623 
624 struct vfsync_info {
625 	struct vnode *vp;
626 	int fastpass;
627 	int synchronous;
628 	int syncdeps;
629 	int lazycount;
630 	int lazylimit;
631 	int skippedbufs;
632 	int (*checkdef)(struct buf *);
633 	int (*cmpfunc)(struct buf *, void *);
634 };
635 
636 int
637 vfsync(struct vnode *vp, int waitfor, int passes,
638 	int (*checkdef)(struct buf *),
639 	int (*waitoutput)(struct vnode *, struct thread *))
640 {
641 	struct vfsync_info info;
642 	int error;
643 
644 	bzero(&info, sizeof(info));
645 	info.vp = vp;
646 	if ((info.checkdef = checkdef) == NULL)
647 		info.syncdeps = 1;
648 
649 	lwkt_gettoken(&vp->v_token);
650 
651 	switch(waitfor) {
652 	case MNT_LAZY | MNT_NOWAIT:
653 	case MNT_LAZY:
654 		/*
655 		 * Lazy (filesystem syncer typ) Asynchronous plus limit the
656 		 * number of data (not meta) pages we try to flush to 1MB.
657 		 * A non-zero return means that lazy limit was reached.
658 		 */
659 		info.lazylimit = 1024 * 1024;
660 		info.syncdeps = 1;
661 		info.cmpfunc = vfsync_lazy_range_cmp;
662 		error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
663 				vfsync_lazy_range_cmp, vfsync_bp, &info);
664 		info.cmpfunc = vfsync_meta_only_cmp;
665 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree,
666 			vfsync_meta_only_cmp, vfsync_bp, &info);
667 		if (error == 0)
668 			vp->v_lazyw = 0;
669 		else if (!RB_EMPTY(&vp->v_rbdirty_tree))
670 			vn_syncer_add(vp, 1);
671 		error = 0;
672 		break;
673 	case MNT_NOWAIT:
674 		/*
675 		 * Asynchronous.  Do a data-only pass and a meta-only pass.
676 		 */
677 		info.syncdeps = 1;
678 		info.cmpfunc = vfsync_data_only_cmp;
679 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
680 			vfsync_bp, &info);
681 		info.cmpfunc = vfsync_meta_only_cmp;
682 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_meta_only_cmp,
683 			vfsync_bp, &info);
684 		error = 0;
685 		break;
686 	default:
687 		/*
688 		 * Synchronous.  Do a data-only pass, then a meta-data+data
689 		 * pass, then additional integrated passes to try to get
690 		 * all the dependancies flushed.
691 		 */
692 		info.cmpfunc = vfsync_data_only_cmp;
693 		info.fastpass = 1;
694 		RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, vfsync_data_only_cmp,
695 			vfsync_bp, &info);
696 		info.fastpass = 0;
697 		error = vfsync_wait_output(vp, waitoutput);
698 		if (error == 0) {
699 			info.skippedbufs = 0;
700 			info.cmpfunc = vfsync_dummy_cmp;
701 			RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
702 				vfsync_bp, &info);
703 			error = vfsync_wait_output(vp, waitoutput);
704 			if (info.skippedbufs) {
705 				kprintf("Warning: vfsync skipped %d dirty "
706 					"buf%s in pass2!\n",
707 					info.skippedbufs,
708 					((info.skippedbufs > 1) ? "s" : ""));
709 			}
710 		}
711 		while (error == 0 && passes > 0 &&
712 		       !RB_EMPTY(&vp->v_rbdirty_tree)
713 		) {
714 			info.skippedbufs = 0;
715 			if (--passes == 0) {
716 				info.synchronous = 1;
717 				info.syncdeps = 1;
718 			}
719 			info.cmpfunc = vfsync_dummy_cmp;
720 			error = RB_SCAN(buf_rb_tree, &vp->v_rbdirty_tree, NULL,
721 					vfsync_bp, &info);
722 			if (error < 0)
723 				error = -error;
724 			info.syncdeps = 1;
725 			if (error == 0)
726 				error = vfsync_wait_output(vp, waitoutput);
727 			if (info.skippedbufs && passes == 0) {
728 				kprintf("Warning: vfsync skipped %d dirty "
729 					"buf%s in final pass!\n",
730 					info.skippedbufs,
731 					((info.skippedbufs > 1) ? "s" : ""));
732 			}
733 		}
734 		if (!RB_EMPTY(&vp->v_rbdirty_tree))
735 			kprintf("dirty bufs left after final pass\n");
736 		break;
737 	}
738 	lwkt_reltoken(&vp->v_token);
739 
740 	return(error);
741 }
742 
743 static int
744 vfsync_wait_output(struct vnode *vp,
745 		   int (*waitoutput)(struct vnode *, struct thread *))
746 {
747 	int error;
748 
749 	error = bio_track_wait(&vp->v_track_write, 0, 0);
750 	if (waitoutput)
751 		error = waitoutput(vp, curthread);
752 	return(error);
753 }
754 
755 static int
756 vfsync_dummy_cmp(struct buf *bp __unused, void *data __unused)
757 {
758 	return(0);
759 }
760 
761 static int
762 vfsync_data_only_cmp(struct buf *bp, void *data)
763 {
764 	if (bp->b_loffset < 0)
765 		return(-1);
766 	return(0);
767 }
768 
769 static int
770 vfsync_meta_only_cmp(struct buf *bp, void *data)
771 {
772 	if (bp->b_loffset < 0)
773 		return(0);
774 	return(1);
775 }
776 
777 static int
778 vfsync_lazy_range_cmp(struct buf *bp, void *data)
779 {
780 	struct vfsync_info *info = data;
781 
782 	if (bp->b_loffset < info->vp->v_lazyw)
783 		return(-1);
784 	return(0);
785 }
786 
787 static int
788 vfsync_bp(struct buf *bp, void *data)
789 {
790 	struct vfsync_info *info = data;
791 	struct vnode *vp = info->vp;
792 	int error;
793 
794 	if (info->fastpass) {
795 		/*
796 		 * Ignore buffers that we cannot immediately lock.
797 		 */
798 		if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
799 			if (BUF_TIMELOCK(bp, LK_EXCLUSIVE, "bflst1", 1)) {
800 				++info->skippedbufs;
801 				return(0);
802 			}
803 		}
804 	} else if (info->synchronous == 0) {
805 		/*
806 		 * Normal pass, give the buffer a little time to become
807 		 * available to us.
808 		 */
809 		if (BUF_TIMELOCK(bp, LK_EXCLUSIVE, "bflst2", hz / 10)) {
810 			++info->skippedbufs;
811 			return(0);
812 		}
813 	} else {
814 		/*
815 		 * Synchronous pass, give the buffer a lot of time before
816 		 * giving up.
817 		 */
818 		if (BUF_TIMELOCK(bp, LK_EXCLUSIVE, "bflst3", hz * 10)) {
819 			++info->skippedbufs;
820 			return(0);
821 		}
822 	}
823 
824 	/*
825 	 * We must revalidate the buffer after locking.
826 	 */
827 	if ((bp->b_flags & B_DELWRI) == 0 ||
828 	    bp->b_vp != info->vp ||
829 	    info->cmpfunc(bp, data)) {
830 		BUF_UNLOCK(bp);
831 		return(0);
832 	}
833 
834 	/*
835 	 * If syncdeps is not set we do not try to write buffers which have
836 	 * dependancies.
837 	 */
838 	if (!info->synchronous && info->syncdeps == 0 && info->checkdef(bp)) {
839 		BUF_UNLOCK(bp);
840 		return(0);
841 	}
842 
843 	/*
844 	 * B_NEEDCOMMIT (primarily used by NFS) is a state where the buffer
845 	 * has been written but an additional handshake with the device
846 	 * is required before we can dispose of the buffer.  We have no idea
847 	 * how to do this so we have to skip these buffers.
848 	 */
849 	if (bp->b_flags & B_NEEDCOMMIT) {
850 		BUF_UNLOCK(bp);
851 		return(0);
852 	}
853 
854 	/*
855 	 * Ask bioops if it is ok to sync.  If not the VFS may have
856 	 * set B_LOCKED so we have to cycle the buffer.
857 	 */
858 	if (LIST_FIRST(&bp->b_dep) != NULL && buf_checkwrite(bp)) {
859 		bremfree(bp);
860 		brelse(bp);
861 		return(0);
862 	}
863 
864 	if (info->synchronous) {
865 		/*
866 		 * Synchronous flushing.  An error may be returned.
867 		 */
868 		bremfree(bp);
869 		error = bwrite(bp);
870 	} else {
871 		/*
872 		 * Asynchronous flushing.  A negative return value simply
873 		 * stops the scan and is not considered an error.  We use
874 		 * this to support limited MNT_LAZY flushes.
875 		 */
876 		vp->v_lazyw = bp->b_loffset;
877 		bremfree(bp);
878 		info->lazycount += cluster_awrite(bp);
879 		waitrunningbufspace();
880 		vm_wait_nominal();
881 		if (info->lazylimit && info->lazycount >= info->lazylimit)
882 			error = 1;
883 		else
884 			error = 0;
885 	}
886 	return(-error);
887 }
888 
889 /*
890  * Associate a buffer with a vnode.
891  *
892  * MPSAFE
893  */
894 int
895 bgetvp(struct vnode *vp, struct buf *bp, int testsize)
896 {
897 	KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));
898 	KKASSERT((bp->b_flags & (B_HASHED|B_DELWRI|B_VNCLEAN|B_VNDIRTY)) == 0);
899 
900 	/*
901 	 * Insert onto list for new vnode.
902 	 */
903 	lwkt_gettoken(&vp->v_token);
904 
905 	if (buf_rb_hash_RB_INSERT(&vp->v_rbhash_tree, bp)) {
906 		lwkt_reltoken(&vp->v_token);
907 		return (EEXIST);
908 	}
909 
910 	/*
911 	 * Diagnostics (mainly for HAMMER debugging).  Check for
912 	 * overlapping buffers.
913 	 */
914 	if (check_buf_overlap) {
915 		struct buf *bx;
916 		bx = buf_rb_hash_RB_PREV(bp);
917 		if (bx) {
918 			if (bx->b_loffset + bx->b_bufsize > bp->b_loffset) {
919 				kprintf("bgetvp: overlapl %016jx/%d %016jx "
920 					"bx %p bp %p\n",
921 					(intmax_t)bx->b_loffset,
922 					bx->b_bufsize,
923 					(intmax_t)bp->b_loffset,
924 					bx, bp);
925 				if (check_buf_overlap > 1)
926 					panic("bgetvp - overlapping buffer");
927 			}
928 		}
929 		bx = buf_rb_hash_RB_NEXT(bp);
930 		if (bx) {
931 			if (bp->b_loffset + testsize > bx->b_loffset) {
932 				kprintf("bgetvp: overlapr %016jx/%d %016jx "
933 					"bp %p bx %p\n",
934 					(intmax_t)bp->b_loffset,
935 					testsize,
936 					(intmax_t)bx->b_loffset,
937 					bp, bx);
938 				if (check_buf_overlap > 1)
939 					panic("bgetvp - overlapping buffer");
940 			}
941 		}
942 	}
943 	bp->b_vp = vp;
944 	bp->b_flags |= B_HASHED;
945 	bp->b_flags |= B_VNCLEAN;
946 	if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp))
947 		panic("reassignbuf: dup lblk/clean vp %p bp %p", vp, bp);
948 	/*vhold(vp);*/
949 	lwkt_reltoken(&vp->v_token);
950 	return(0);
951 }
952 
953 /*
954  * Disassociate a buffer from a vnode.
955  *
956  * MPSAFE
957  */
958 void
959 brelvp(struct buf *bp)
960 {
961 	struct vnode *vp;
962 
963 	KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
964 
965 	/*
966 	 * Delete from old vnode list, if on one.
967 	 */
968 	vp = bp->b_vp;
969 	lwkt_gettoken(&vp->v_token);
970 	if (bp->b_flags & (B_VNDIRTY | B_VNCLEAN)) {
971 		if (bp->b_flags & B_VNDIRTY)
972 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
973 		else
974 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
975 		bp->b_flags &= ~(B_VNDIRTY | B_VNCLEAN);
976 	}
977 	if (bp->b_flags & B_HASHED) {
978 		buf_rb_hash_RB_REMOVE(&vp->v_rbhash_tree, bp);
979 		bp->b_flags &= ~B_HASHED;
980 	}
981 
982 	/*
983 	 * Only remove from synclist when no dirty buffers are left AND
984 	 * the VFS has not flagged the vnode's inode as being dirty.
985 	 */
986 	if ((vp->v_flag & (VONWORKLST | VISDIRTY | VOBJDIRTY)) == VONWORKLST &&
987 	    RB_EMPTY(&vp->v_rbdirty_tree)) {
988 		vn_syncer_remove(vp, 0);
989 	}
990 	bp->b_vp = NULL;
991 
992 	lwkt_reltoken(&vp->v_token);
993 
994 	/*vdrop(vp);*/
995 }
996 
997 /*
998  * Reassign the buffer to the proper clean/dirty list based on B_DELWRI.
999  * This routine is called when the state of the B_DELWRI bit is changed.
1000  *
1001  * Must be called with vp->v_token held.
1002  * MPSAFE
1003  */
1004 void
1005 reassignbuf(struct buf *bp)
1006 {
1007 	struct vnode *vp = bp->b_vp;
1008 	int delay;
1009 
1010 	ASSERT_LWKT_TOKEN_HELD(&vp->v_token);
1011 	++reassignbufcalls;
1012 
1013 	/*
1014 	 * B_PAGING flagged buffers cannot be reassigned because their vp
1015 	 * is not fully linked in.
1016 	 */
1017 	if (bp->b_flags & B_PAGING)
1018 		panic("cannot reassign paging buffer");
1019 
1020 	if (bp->b_flags & B_DELWRI) {
1021 		/*
1022 		 * Move to the dirty list, add the vnode to the worklist
1023 		 */
1024 		if (bp->b_flags & B_VNCLEAN) {
1025 			buf_rb_tree_RB_REMOVE(&vp->v_rbclean_tree, bp);
1026 			bp->b_flags &= ~B_VNCLEAN;
1027 		}
1028 		if ((bp->b_flags & B_VNDIRTY) == 0) {
1029 			if (buf_rb_tree_RB_INSERT(&vp->v_rbdirty_tree, bp)) {
1030 				panic("reassignbuf: dup lblk vp %p bp %p",
1031 				      vp, bp);
1032 			}
1033 			bp->b_flags |= B_VNDIRTY;
1034 		}
1035 		if ((vp->v_flag & VONWORKLST) == 0) {
1036 			switch (vp->v_type) {
1037 			case VDIR:
1038 				delay = dirdelay;
1039 				break;
1040 			case VCHR:
1041 			case VBLK:
1042 				if (vp->v_rdev &&
1043 				    vp->v_rdev->si_mountpoint != NULL) {
1044 					delay = metadelay;
1045 					break;
1046 				}
1047 				/* fall through */
1048 			default:
1049 				delay = filedelay;
1050 			}
1051 			vn_syncer_add(vp, delay);
1052 		}
1053 	} else {
1054 		/*
1055 		 * Move to the clean list, remove the vnode from the worklist
1056 		 * if no dirty blocks remain.
1057 		 */
1058 		if (bp->b_flags & B_VNDIRTY) {
1059 			buf_rb_tree_RB_REMOVE(&vp->v_rbdirty_tree, bp);
1060 			bp->b_flags &= ~B_VNDIRTY;
1061 		}
1062 		if ((bp->b_flags & B_VNCLEAN) == 0) {
1063 			if (buf_rb_tree_RB_INSERT(&vp->v_rbclean_tree, bp)) {
1064 				panic("reassignbuf: dup lblk vp %p bp %p",
1065 				      vp, bp);
1066 			}
1067 			bp->b_flags |= B_VNCLEAN;
1068 		}
1069 
1070 		/*
1071 		 * Only remove from synclist when no dirty buffers are left
1072 		 * AND the VFS has not flagged the vnode's inode as being
1073 		 * dirty.
1074 		 */
1075 		if ((vp->v_flag & (VONWORKLST | VISDIRTY | VOBJDIRTY)) ==
1076 		     VONWORKLST &&
1077 		    RB_EMPTY(&vp->v_rbdirty_tree)) {
1078 			vn_syncer_remove(vp, 0);
1079 		}
1080 	}
1081 }
1082 
1083 /*
1084  * Create a vnode for a block device.  Used for mounting the root file
1085  * system.
1086  *
1087  * A vref()'d vnode is returned.
1088  */
1089 extern struct vop_ops *devfs_vnode_dev_vops_p;
1090 int
1091 bdevvp(cdev_t dev, struct vnode **vpp)
1092 {
1093 	struct vnode *vp;
1094 	struct vnode *nvp;
1095 	int error;
1096 
1097 	if (dev == NULL) {
1098 		*vpp = NULLVP;
1099 		return (ENXIO);
1100 	}
1101 	error = getspecialvnode(VT_NON, NULL, &devfs_vnode_dev_vops_p,
1102 				&nvp, 0, 0);
1103 	if (error) {
1104 		*vpp = NULLVP;
1105 		return (error);
1106 	}
1107 	vp = nvp;
1108 	vp->v_type = VCHR;
1109 #if 0
1110 	vp->v_rdev = dev;
1111 #endif
1112 	v_associate_rdev(vp, dev);
1113 	vp->v_umajor = dev->si_umajor;
1114 	vp->v_uminor = dev->si_uminor;
1115 	vx_unlock(vp);
1116 	*vpp = vp;
1117 	return (0);
1118 }
1119 
1120 int
1121 v_associate_rdev(struct vnode *vp, cdev_t dev)
1122 {
1123 	if (dev == NULL)
1124 		return(ENXIO);
1125 	if (dev_is_good(dev) == 0)
1126 		return(ENXIO);
1127 	KKASSERT(vp->v_rdev == NULL);
1128 	vp->v_rdev = reference_dev(dev);
1129 	lwkt_gettoken(&spechash_token);
1130 	SLIST_INSERT_HEAD(&dev->si_hlist, vp, v_cdevnext);
1131 	lwkt_reltoken(&spechash_token);
1132 	return(0);
1133 }
1134 
1135 void
1136 v_release_rdev(struct vnode *vp)
1137 {
1138 	cdev_t dev;
1139 
1140 	if ((dev = vp->v_rdev) != NULL) {
1141 		lwkt_gettoken(&spechash_token);
1142 		SLIST_REMOVE(&dev->si_hlist, vp, vnode, v_cdevnext);
1143 		vp->v_rdev = NULL;
1144 		release_dev(dev);
1145 		lwkt_reltoken(&spechash_token);
1146 	}
1147 }
1148 
1149 /*
1150  * Add a vnode to the alias list hung off the cdev_t.  We only associate
1151  * the device number with the vnode.  The actual device is not associated
1152  * until the vnode is opened (usually in spec_open()), and will be
1153  * disassociated on last close.
1154  */
1155 void
1156 addaliasu(struct vnode *nvp, int x, int y)
1157 {
1158 	if (nvp->v_type != VBLK && nvp->v_type != VCHR)
1159 		panic("addaliasu on non-special vnode");
1160 	nvp->v_umajor = x;
1161 	nvp->v_uminor = y;
1162 }
1163 
1164 /*
1165  * Simple call that a filesystem can make to try to get rid of a
1166  * vnode.  It will fail if anyone is referencing the vnode (including
1167  * the caller).
1168  *
1169  * The filesystem can check whether its in-memory inode structure still
1170  * references the vp on return.
1171  *
1172  * May only be called if the vnode is in a known state (i.e. being prevented
1173  * from being deallocated by some other condition such as a vfs inode hold).
1174  */
1175 void
1176 vclean_unlocked(struct vnode *vp)
1177 {
1178 	vx_get(vp);
1179 	if (VREFCNT(vp) <= 1)
1180 		vgone_vxlocked(vp);
1181 	vx_put(vp);
1182 }
1183 
1184 /*
1185  * Disassociate a vnode from its underlying filesystem.
1186  *
1187  * The vnode must be VX locked and referenced.  In all normal situations
1188  * there are no active references.  If vclean_vxlocked() is called while
1189  * there are active references, the vnode is being ripped out and we have
1190  * to call VOP_CLOSE() as appropriate before we can reclaim it.
1191  */
1192 void
1193 vclean_vxlocked(struct vnode *vp, int flags)
1194 {
1195 	int active;
1196 	int n;
1197 	vm_object_t object;
1198 	struct namecache *ncp;
1199 
1200 	/*
1201 	 * If the vnode has already been reclaimed we have nothing to do.
1202 	 */
1203 	if (vp->v_flag & VRECLAIMED)
1204 		return;
1205 
1206 	/*
1207 	 * Set flag to interlock operation, flag finalization to ensure
1208 	 * that the vnode winds up on the inactive list, and set v_act to 0.
1209 	 */
1210 	vsetflags(vp, VRECLAIMED);
1211 	atomic_set_int(&vp->v_refcnt, VREF_FINALIZE);
1212 	vp->v_act = 0;
1213 
1214 	if (verbose_reclaims) {
1215 		if ((ncp = TAILQ_FIRST(&vp->v_namecache)) != NULL)
1216 			kprintf("Debug: reclaim %p %s\n", vp, ncp->nc_name);
1217 	}
1218 
1219 	/*
1220 	 * Scrap the vfs cache
1221 	 */
1222 	while (cache_inval_vp(vp, 0) != 0) {
1223 		kprintf("Warning: vnode %p clean/cache_resolution "
1224 			"race detected\n", vp);
1225 		tsleep(vp, 0, "vclninv", 2);
1226 	}
1227 
1228 	/*
1229 	 * Check to see if the vnode is in use. If so we have to reference it
1230 	 * before we clean it out so that its count cannot fall to zero and
1231 	 * generate a race against ourselves to recycle it.
1232 	 */
1233 	active = (VREFCNT(vp) > 0);
1234 
1235 	/*
1236 	 * Clean out any buffers associated with the vnode and destroy its
1237 	 * object, if it has one.
1238 	 */
1239 	vinvalbuf(vp, V_SAVE, 0, 0);
1240 	KKASSERT(lockcountnb(&vp->v_lock) == 1);
1241 
1242 	/*
1243 	 * If purging an active vnode (typically during a forced unmount
1244 	 * or reboot), it must be closed and deactivated before being
1245 	 * reclaimed.  This isn't really all that safe, but what can
1246 	 * we do? XXX.
1247 	 *
1248 	 * Note that neither of these routines unlocks the vnode.
1249 	 */
1250 	if (active && (flags & DOCLOSE)) {
1251 		while ((n = vp->v_opencount) != 0) {
1252 			if (vp->v_writecount)
1253 				VOP_CLOSE(vp, FWRITE|FNONBLOCK, NULL);
1254 			else
1255 				VOP_CLOSE(vp, FNONBLOCK, NULL);
1256 			if (vp->v_opencount == n) {
1257 				kprintf("Warning: unable to force-close"
1258 				       " vnode %p\n", vp);
1259 				break;
1260 			}
1261 		}
1262 	}
1263 
1264 	/*
1265 	 * If the vnode has not been deactivated, deactivated it.  Deactivation
1266 	 * can create new buffers and VM pages so we have to call vinvalbuf()
1267 	 * again to make sure they all get flushed.
1268 	 *
1269 	 * This can occur if a file with a link count of 0 needs to be
1270 	 * truncated.
1271 	 *
1272 	 * If the vnode is already dead don't try to deactivate it.
1273 	 */
1274 	if ((vp->v_flag & VINACTIVE) == 0) {
1275 		vsetflags(vp, VINACTIVE);
1276 		if (vp->v_mount)
1277 			VOP_INACTIVE(vp);
1278 		vinvalbuf(vp, V_SAVE, 0, 0);
1279 	}
1280 	KKASSERT(lockcountnb(&vp->v_lock) == 1);
1281 
1282 	/*
1283 	 * If the vnode has an object, destroy it.
1284 	 */
1285 	while ((object = vp->v_object) != NULL) {
1286 		vm_object_hold(object);
1287 		if (object == vp->v_object)
1288 			break;
1289 		vm_object_drop(object);
1290 	}
1291 
1292 	if (object != NULL) {
1293 		if (object->ref_count == 0) {
1294 			if ((object->flags & OBJ_DEAD) == 0)
1295 				vm_object_terminate(object);
1296 			vm_object_drop(object);
1297 			vclrflags(vp, VOBJBUF);
1298 		} else {
1299 			vm_pager_deallocate(object);
1300 			vclrflags(vp, VOBJBUF);
1301 			vm_object_drop(object);
1302 		}
1303 	}
1304 	KKASSERT((vp->v_flag & VOBJBUF) == 0);
1305 
1306 	/*
1307 	 * Reclaim the vnode if not already dead.
1308 	 */
1309 	if (vp->v_mount && VOP_RECLAIM(vp))
1310 		panic("vclean: cannot reclaim");
1311 
1312 	/*
1313 	 * Done with purge, notify sleepers of the grim news.
1314 	 */
1315 	vp->v_ops = &dead_vnode_vops_p;
1316 	vn_gone(vp);
1317 	vp->v_tag = VT_NON;
1318 
1319 	/*
1320 	 * If we are destroying an active vnode, reactivate it now that
1321 	 * we have reassociated it with deadfs.  This prevents the system
1322 	 * from crashing on the vnode due to it being unexpectedly marked
1323 	 * as inactive or reclaimed.
1324 	 */
1325 	if (active && (flags & DOCLOSE)) {
1326 		vclrflags(vp, VINACTIVE | VRECLAIMED);
1327 	}
1328 }
1329 
1330 /*
1331  * Eliminate all activity associated with the requested vnode
1332  * and with all vnodes aliased to the requested vnode.
1333  *
1334  * The vnode must be referenced but should not be locked.
1335  */
1336 int
1337 vrevoke(struct vnode *vp, struct ucred *cred)
1338 {
1339 	struct vnode *vq;
1340 	struct vnode *vqn;
1341 	cdev_t dev;
1342 	int error;
1343 
1344 	/*
1345 	 * If the vnode has a device association, scrap all vnodes associated
1346 	 * with the device.  Don't let the device disappear on us while we
1347 	 * are scrapping the vnodes.
1348 	 *
1349 	 * The passed vp will probably show up in the list, do not VX lock
1350 	 * it twice!
1351 	 *
1352 	 * Releasing the vnode's rdev here can mess up specfs's call to
1353 	 * device close, so don't do it.  The vnode has been disassociated
1354 	 * and the device will be closed after the last ref on the related
1355 	 * fp goes away (if not still open by e.g. the kernel).
1356 	 */
1357 	if (vp->v_type != VCHR) {
1358 		error = fdrevoke(vp, DTYPE_VNODE, cred);
1359 		return (error);
1360 	}
1361 	if ((dev = vp->v_rdev) == NULL) {
1362 		return(0);
1363 	}
1364 	reference_dev(dev);
1365 	lwkt_gettoken(&spechash_token);
1366 
1367 restart:
1368 	vqn = SLIST_FIRST(&dev->si_hlist);
1369 	if (vqn)
1370 		vhold(vqn);
1371 	while ((vq = vqn) != NULL) {
1372 		if (VREFCNT(vq) > 0) {
1373 			vref(vq);
1374 			fdrevoke(vq, DTYPE_VNODE, cred);
1375 			/*v_release_rdev(vq);*/
1376 			vrele(vq);
1377 			if (vq->v_rdev != dev) {
1378 				vdrop(vq);
1379 				goto restart;
1380 			}
1381 		}
1382 		vqn = SLIST_NEXT(vq, v_cdevnext);
1383 		if (vqn)
1384 			vhold(vqn);
1385 		vdrop(vq);
1386 	}
1387 	lwkt_reltoken(&spechash_token);
1388 	dev_drevoke(dev);
1389 	release_dev(dev);
1390 	return (0);
1391 }
1392 
1393 /*
1394  * This is called when the object underlying a vnode is being destroyed,
1395  * such as in a remove().  Try to recycle the vnode immediately if the
1396  * only active reference is our reference.
1397  *
1398  * Directory vnodes in the namecache with children cannot be immediately
1399  * recycled because numerous VOP_N*() ops require them to be stable.
1400  *
1401  * To avoid recursive recycling from VOP_INACTIVE implemenetations this
1402  * function is a NOP if VRECLAIMED is already set.
1403  */
1404 int
1405 vrecycle(struct vnode *vp)
1406 {
1407 	if (VREFCNT(vp) <= 1 && (vp->v_flag & VRECLAIMED) == 0) {
1408 		if (cache_inval_vp_nonblock(vp))
1409 			return(0);
1410 		vgone_vxlocked(vp);
1411 		return (1);
1412 	}
1413 	return (0);
1414 }
1415 
1416 /*
1417  * Return the maximum I/O size allowed for strategy calls on VP.
1418  *
1419  * If vp is VCHR or VBLK we dive the device, otherwise we use
1420  * the vp's mount info.
1421  *
1422  * The returned value is clamped at MAXPHYS as most callers cannot use
1423  * buffers larger than that size.
1424  */
1425 int
1426 vmaxiosize(struct vnode *vp)
1427 {
1428 	int maxiosize;
1429 
1430 	if (vp->v_type == VBLK || vp->v_type == VCHR)
1431 		maxiosize = vp->v_rdev->si_iosize_max;
1432 	else
1433 		maxiosize = vp->v_mount->mnt_iosize_max;
1434 
1435 	if (maxiosize > MAXPHYS)
1436 		maxiosize = MAXPHYS;
1437 	return (maxiosize);
1438 }
1439 
1440 /*
1441  * Eliminate all activity associated with a vnode in preparation for
1442  * destruction.
1443  *
1444  * The vnode must be VX locked and refd and will remain VX locked and refd
1445  * on return.  This routine may be called with the vnode in any state, as
1446  * long as it is VX locked.  The vnode will be cleaned out and marked
1447  * VRECLAIMED but will not actually be reused until all existing refs and
1448  * holds go away.
1449  *
1450  * NOTE: This routine may be called on a vnode which has not yet been
1451  * already been deactivated (VOP_INACTIVE), or on a vnode which has
1452  * already been reclaimed.
1453  *
1454  * This routine is not responsible for placing us back on the freelist.
1455  * Instead, it happens automatically when the caller releases the VX lock
1456  * (assuming there aren't any other references).
1457  */
1458 void
1459 vgone_vxlocked(struct vnode *vp)
1460 {
1461 	/*
1462 	 * assert that the VX lock is held.  This is an absolute requirement
1463 	 * now for vgone_vxlocked() to be called.
1464 	 */
1465 	KKASSERT(lockcountnb(&vp->v_lock) == 1);
1466 
1467 	/*
1468 	 * Clean out the filesystem specific data and set the VRECLAIMED
1469 	 * bit.  Also deactivate the vnode if necessary.
1470 	 *
1471 	 * The vnode should have automatically been removed from the syncer
1472 	 * list as syncer/dirty flags cleared during the cleaning.
1473 	 */
1474 	vclean_vxlocked(vp, DOCLOSE);
1475 
1476 	/*
1477 	 * Normally panic if the vnode is still dirty, unless we are doing
1478 	 * a forced unmount (tmpfs typically).
1479 	 */
1480 	if (vp->v_flag & VONWORKLST) {
1481 		if (vp->v_mount->mnt_kern_flag & MNTK_UNMOUNTF) {
1482 			/* force removal */
1483 			vn_syncer_remove(vp, 1);
1484 		} else {
1485 			panic("vp %p still dirty in vgone after flush", vp);
1486 		}
1487 	}
1488 
1489 	/*
1490 	 * Delete from old mount point vnode list, if on one.
1491 	 */
1492 	if (vp->v_mount != NULL) {
1493 		KKASSERT(vp->v_data == NULL);
1494 		insmntque(vp, NULL);
1495 	}
1496 
1497 	/*
1498 	 * If special device, remove it from special device alias list
1499 	 * if it is on one.  This should normally only occur if a vnode is
1500 	 * being revoked as the device should otherwise have been released
1501 	 * naturally.
1502 	 */
1503 	if ((vp->v_type == VBLK || vp->v_type == VCHR) && vp->v_rdev != NULL) {
1504 		v_release_rdev(vp);
1505 	}
1506 
1507 	/*
1508 	 * Set us to VBAD
1509 	 */
1510 	vp->v_type = VBAD;
1511 }
1512 
1513 /*
1514  * Lookup a vnode by device number.
1515  *
1516  * Returns non-zero and *vpp set to a vref'd vnode on success.
1517  * Returns zero on failure.
1518  */
1519 int
1520 vfinddev(cdev_t dev, enum vtype type, struct vnode **vpp)
1521 {
1522 	struct vnode *vp;
1523 
1524 	lwkt_gettoken(&spechash_token);
1525 	SLIST_FOREACH(vp, &dev->si_hlist, v_cdevnext) {
1526 		if (type == vp->v_type) {
1527 			*vpp = vp;
1528 			vref(vp);
1529 			lwkt_reltoken(&spechash_token);
1530 			return (1);
1531 		}
1532 	}
1533 	lwkt_reltoken(&spechash_token);
1534 	return (0);
1535 }
1536 
1537 /*
1538  * Calculate the total number of references to a special device.  This
1539  * routine may only be called for VBLK and VCHR vnodes since v_rdev is
1540  * an overloaded field.  Since udev2dev can now return NULL, we have
1541  * to check for a NULL v_rdev.
1542  */
1543 int
1544 count_dev(cdev_t dev)
1545 {
1546 	struct vnode *vp;
1547 	int count = 0;
1548 
1549 	if (SLIST_FIRST(&dev->si_hlist)) {
1550 		lwkt_gettoken(&spechash_token);
1551 		SLIST_FOREACH(vp, &dev->si_hlist, v_cdevnext) {
1552 			count += vp->v_opencount;
1553 		}
1554 		lwkt_reltoken(&spechash_token);
1555 	}
1556 	return(count);
1557 }
1558 
1559 int
1560 vcount(struct vnode *vp)
1561 {
1562 	if (vp->v_rdev == NULL)
1563 		return(0);
1564 	return(count_dev(vp->v_rdev));
1565 }
1566 
1567 /*
1568  * Initialize VMIO for a vnode.  This routine MUST be called before a
1569  * VFS can issue buffer cache ops on a vnode.  It is typically called
1570  * when a vnode is initialized from its inode.
1571  */
1572 int
1573 vinitvmio(struct vnode *vp, off_t filesize, int blksize, int boff)
1574 {
1575 	vm_object_t object;
1576 	int error = 0;
1577 
1578 	object = vp->v_object;
1579 	if (object) {
1580 		vm_object_hold(object);
1581 		KKASSERT(vp->v_object == object);
1582 	}
1583 
1584 	if (object == NULL) {
1585 		object = vnode_pager_alloc(vp, filesize, 0, 0, blksize, boff);
1586 
1587 		/*
1588 		 * Dereference the reference we just created.  This assumes
1589 		 * that the object is associated with the vp.  Allow it to
1590 		 * have zero refs.  It cannot be destroyed as long as it
1591 		 * is associated with the vnode.
1592 		 */
1593 		vm_object_hold(object);
1594 		atomic_add_int(&object->ref_count, -1);
1595 		vrele(vp);
1596 	} else {
1597 		KKASSERT((object->flags & OBJ_DEAD) == 0);
1598 	}
1599 	KASSERT(vp->v_object != NULL, ("vinitvmio: NULL object"));
1600 	vsetflags(vp, VOBJBUF);
1601 	vm_object_drop(object);
1602 
1603 	return (error);
1604 }
1605 
1606 
1607 /*
1608  * Print out a description of a vnode.
1609  */
1610 static char *typename[] =
1611 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
1612 
1613 void
1614 vprint(char *label, struct vnode *vp)
1615 {
1616 	char buf[96];
1617 
1618 	if (label != NULL)
1619 		kprintf("%s: %p: ", label, (void *)vp);
1620 	else
1621 		kprintf("%p: ", (void *)vp);
1622 	kprintf("type %s, refcnt %08x, writecount %d, holdcnt %d,",
1623 		typename[vp->v_type],
1624 		vp->v_refcnt, vp->v_writecount, vp->v_auxrefs);
1625 	buf[0] = '\0';
1626 	if (vp->v_flag & VROOT)
1627 		strcat(buf, "|VROOT");
1628 	if (vp->v_flag & VPFSROOT)
1629 		strcat(buf, "|VPFSROOT");
1630 	if (vp->v_flag & VTEXT)
1631 		strcat(buf, "|VTEXT");
1632 	if (vp->v_flag & VSYSTEM)
1633 		strcat(buf, "|VSYSTEM");
1634 	if (vp->v_flag & VOBJBUF)
1635 		strcat(buf, "|VOBJBUF");
1636 	if (buf[0] != '\0')
1637 		kprintf(" flags (%s)", &buf[1]);
1638 	if (vp->v_data == NULL) {
1639 		kprintf("\n");
1640 	} else {
1641 		kprintf("\n\t");
1642 		VOP_PRINT(vp);
1643 	}
1644 }
1645 
1646 /*
1647  * Do the usual access checking.
1648  * file_mode, uid and gid are from the vnode in question,
1649  * while acc_mode and cred are from the VOP_ACCESS parameter list
1650  */
1651 int
1652 vaccess(enum vtype type, mode_t file_mode, uid_t uid, gid_t gid,
1653     mode_t acc_mode, struct ucred *cred)
1654 {
1655 	mode_t mask;
1656 	int ismember;
1657 
1658 	/*
1659 	 * Super-user always gets read/write access, but execute access depends
1660 	 * on at least one execute bit being set.
1661 	 */
1662 	if (priv_check_cred(cred, PRIV_ROOT, 0) == 0) {
1663 		if ((acc_mode & VEXEC) && type != VDIR &&
1664 		    (file_mode & (S_IXUSR|S_IXGRP|S_IXOTH)) == 0)
1665 			return (EACCES);
1666 		return (0);
1667 	}
1668 
1669 	mask = 0;
1670 
1671 	/* Otherwise, check the owner. */
1672 	if (cred->cr_uid == uid) {
1673 		if (acc_mode & VEXEC)
1674 			mask |= S_IXUSR;
1675 		if (acc_mode & VREAD)
1676 			mask |= S_IRUSR;
1677 		if (acc_mode & VWRITE)
1678 			mask |= S_IWUSR;
1679 		return ((file_mode & mask) == mask ? 0 : EACCES);
1680 	}
1681 
1682 	/* Otherwise, check the groups. */
1683 	ismember = groupmember(gid, cred);
1684 	if (cred->cr_svgid == gid || ismember) {
1685 		if (acc_mode & VEXEC)
1686 			mask |= S_IXGRP;
1687 		if (acc_mode & VREAD)
1688 			mask |= S_IRGRP;
1689 		if (acc_mode & VWRITE)
1690 			mask |= S_IWGRP;
1691 		return ((file_mode & mask) == mask ? 0 : EACCES);
1692 	}
1693 
1694 	/* Otherwise, check everyone else. */
1695 	if (acc_mode & VEXEC)
1696 		mask |= S_IXOTH;
1697 	if (acc_mode & VREAD)
1698 		mask |= S_IROTH;
1699 	if (acc_mode & VWRITE)
1700 		mask |= S_IWOTH;
1701 	return ((file_mode & mask) == mask ? 0 : EACCES);
1702 }
1703 
1704 #ifdef DDB
1705 #include <ddb/ddb.h>
1706 
1707 static int db_show_locked_vnodes(struct mount *mp, void *data);
1708 
1709 /*
1710  * List all of the locked vnodes in the system.
1711  * Called when debugging the kernel.
1712  */
1713 DB_SHOW_COMMAND(lockedvnodes, lockedvnodes)
1714 {
1715 	kprintf("Locked vnodes\n");
1716 	mountlist_scan(db_show_locked_vnodes, NULL,
1717 			MNTSCAN_FORWARD|MNTSCAN_NOBUSY);
1718 }
1719 
1720 static int
1721 db_show_locked_vnodes(struct mount *mp, void *data __unused)
1722 {
1723 	struct vnode *vp;
1724 
1725 	TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
1726 		if (vn_islocked(vp))
1727 			vprint(NULL, vp);
1728 	}
1729 	return(0);
1730 }
1731 #endif
1732 
1733 /*
1734  * Top level filesystem related information gathering.
1735  */
1736 static int	sysctl_ovfs_conf (SYSCTL_HANDLER_ARGS);
1737 
1738 static int
1739 vfs_sysctl(SYSCTL_HANDLER_ARGS)
1740 {
1741 	int *name = (int *)arg1 - 1;	/* XXX */
1742 	u_int namelen = arg2 + 1;	/* XXX */
1743 	struct vfsconf *vfsp;
1744 	int maxtypenum;
1745 
1746 #if 1 || defined(COMPAT_PRELITE2)
1747 	/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
1748 	if (namelen == 1)
1749 		return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
1750 #endif
1751 
1752 #ifdef notyet
1753 	/* all sysctl names at this level are at least name and field */
1754 	if (namelen < 2)
1755 		return (ENOTDIR);		/* overloaded */
1756 	if (name[0] != VFS_GENERIC) {
1757 		vfsp = vfsconf_find_by_typenum(name[0]);
1758 		if (vfsp == NULL)
1759 			return (EOPNOTSUPP);
1760 		return ((*vfsp->vfc_vfsops->vfs_sysctl)(&name[1], namelen - 1,
1761 		    oldp, oldlenp, newp, newlen, p));
1762 	}
1763 #endif
1764 	switch (name[1]) {
1765 	case VFS_MAXTYPENUM:
1766 		if (namelen != 2)
1767 			return (ENOTDIR);
1768 		maxtypenum = vfsconf_get_maxtypenum();
1769 		return (SYSCTL_OUT(req, &maxtypenum, sizeof(maxtypenum)));
1770 	case VFS_CONF:
1771 		if (namelen != 3)
1772 			return (ENOTDIR);	/* overloaded */
1773 		vfsp = vfsconf_find_by_typenum(name[2]);
1774 		if (vfsp == NULL)
1775 			return (EOPNOTSUPP);
1776 		return (SYSCTL_OUT(req, vfsp, sizeof *vfsp));
1777 	}
1778 	return (EOPNOTSUPP);
1779 }
1780 
1781 SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD, vfs_sysctl,
1782 	"Generic filesystem");
1783 
1784 #if 1 || defined(COMPAT_PRELITE2)
1785 
1786 static int
1787 sysctl_ovfs_conf_iter(struct vfsconf *vfsp, void *data)
1788 {
1789 	int error;
1790 	struct ovfsconf ovfs;
1791 	struct sysctl_req *req = (struct sysctl_req*) data;
1792 
1793 	bzero(&ovfs, sizeof(ovfs));
1794 	ovfs.vfc_vfsops = vfsp->vfc_vfsops;	/* XXX used as flag */
1795 	strcpy(ovfs.vfc_name, vfsp->vfc_name);
1796 	ovfs.vfc_index = vfsp->vfc_typenum;
1797 	ovfs.vfc_refcount = vfsp->vfc_refcount;
1798 	ovfs.vfc_flags = vfsp->vfc_flags;
1799 	error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
1800 	if (error)
1801 		return error; /* abort iteration with error code */
1802 	else
1803 		return 0; /* continue iterating with next element */
1804 }
1805 
1806 static int
1807 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
1808 {
1809 	return vfsconf_each(sysctl_ovfs_conf_iter, (void*)req);
1810 }
1811 
1812 #endif /* 1 || COMPAT_PRELITE2 */
1813 
1814 /*
1815  * Check to see if a filesystem is mounted on a block device.
1816  */
1817 int
1818 vfs_mountedon(struct vnode *vp)
1819 {
1820 	cdev_t dev;
1821 
1822 	if ((dev = vp->v_rdev) == NULL) {
1823 /*		if (vp->v_type != VBLK)
1824 			dev = get_dev(vp->v_uminor, vp->v_umajor); */
1825 	}
1826 	if (dev != NULL && dev->si_mountpoint)
1827 		return (EBUSY);
1828 	return (0);
1829 }
1830 
1831 /*
1832  * Unmount all filesystems. The list is traversed in reverse order
1833  * of mounting to avoid dependencies.
1834  *
1835  * We want the umountall to be able to break out of its loop if a
1836  * failure occurs, after scanning all possible mounts, so the callback
1837  * returns 0 on error.
1838  *
1839  * NOTE: Do not call mountlist_remove(mp) on error any more, this will
1840  *	 confuse mountlist_scan()'s unbusy check.
1841  */
1842 static int vfs_umountall_callback(struct mount *mp, void *data);
1843 
1844 void
1845 vfs_unmountall(void)
1846 {
1847 	int count;
1848 
1849 	do {
1850 		count = mountlist_scan(vfs_umountall_callback,
1851 					NULL, MNTSCAN_REVERSE|MNTSCAN_NOBUSY);
1852 	} while (count);
1853 }
1854 
1855 static
1856 int
1857 vfs_umountall_callback(struct mount *mp, void *data)
1858 {
1859 	int error;
1860 
1861 	error = dounmount(mp, MNT_FORCE);
1862 	if (error) {
1863 		kprintf("unmount of filesystem mounted from %s failed (",
1864 			mp->mnt_stat.f_mntfromname);
1865 		if (error == EBUSY)
1866 			kprintf("BUSY)\n");
1867 		else
1868 			kprintf("%d)\n", error);
1869 		return 0;
1870 	} else {
1871 		return 1;
1872 	}
1873 }
1874 
1875 /*
1876  * Checks the mount flags for parameter mp and put the names comma-separated
1877  * into a string buffer buf with a size limit specified by len.
1878  *
1879  * It returns the number of bytes written into buf, and (*errorp) will be
1880  * set to 0, EINVAL (if passed length is 0), or ENOSPC (supplied buffer was
1881  * not large enough).  The buffer will be 0-terminated if len was not 0.
1882  */
1883 size_t
1884 vfs_flagstostr(int flags, const struct mountctl_opt *optp,
1885 	       char *buf, size_t len, int *errorp)
1886 {
1887 	static const struct mountctl_opt optnames[] = {
1888 		{ MNT_RDONLY,           "read-only" },
1889 		{ MNT_SYNCHRONOUS,      "synchronous" },
1890 		{ MNT_NOEXEC,           "noexec" },
1891 		{ MNT_NOSUID,           "nosuid" },
1892 		{ MNT_NODEV,            "nodev" },
1893 		{ MNT_AUTOMOUNTED,      "automounted" },
1894 		{ MNT_ASYNC,            "asynchronous" },
1895 		{ MNT_SUIDDIR,          "suiddir" },
1896 		{ MNT_SOFTDEP,          "soft-updates" },
1897 		{ MNT_NOSYMFOLLOW,      "nosymfollow" },
1898 		{ MNT_TRIM,             "trim" },
1899 		{ MNT_NOATIME,          "noatime" },
1900 		{ MNT_NOCLUSTERR,       "noclusterr" },
1901 		{ MNT_NOCLUSTERW,       "noclusterw" },
1902 		{ MNT_EXRDONLY,         "NFS read-only" },
1903 		{ MNT_EXPORTED,         "NFS exported" },
1904 		/* Remaining NFS flags could come here */
1905 		{ MNT_LOCAL,            "local" },
1906 		{ MNT_QUOTA,            "with-quotas" },
1907 		/* { MNT_ROOTFS,           "rootfs" }, */
1908 		/* { MNT_IGNORE,           "ignore" }, */
1909 		{ 0,			NULL}
1910 	};
1911 	int bwritten;
1912 	int bleft;
1913 	int optlen;
1914 	int actsize;
1915 
1916 	*errorp = 0;
1917 	bwritten = 0;
1918 	bleft = len - 1;	/* leave room for trailing \0 */
1919 
1920 	/*
1921 	 * Checks the size of the string. If it contains
1922 	 * any data, then we will append the new flags to
1923 	 * it.
1924 	 */
1925 	actsize = strlen(buf);
1926 	if (actsize > 0)
1927 		buf += actsize;
1928 
1929 	/* Default flags if no flags passed */
1930 	if (optp == NULL)
1931 		optp = optnames;
1932 
1933 	if (bleft < 0) {	/* degenerate case, 0-length buffer */
1934 		*errorp = EINVAL;
1935 		return(0);
1936 	}
1937 
1938 	for (; flags && optp->o_opt; ++optp) {
1939 		if ((flags & optp->o_opt) == 0)
1940 			continue;
1941 		optlen = strlen(optp->o_name);
1942 		if (bwritten || actsize > 0) {
1943 			if (bleft < 2) {
1944 				*errorp = ENOSPC;
1945 				break;
1946 			}
1947 			buf[bwritten++] = ',';
1948 			buf[bwritten++] = ' ';
1949 			bleft -= 2;
1950 		}
1951 		if (bleft < optlen) {
1952 			*errorp = ENOSPC;
1953 			break;
1954 		}
1955 		bcopy(optp->o_name, buf + bwritten, optlen);
1956 		bwritten += optlen;
1957 		bleft -= optlen;
1958 		flags &= ~optp->o_opt;
1959 	}
1960 
1961 	/*
1962 	 * Space already reserved for trailing \0
1963 	 */
1964 	buf[bwritten] = 0;
1965 	return (bwritten);
1966 }
1967 
1968 /*
1969  * Build hash lists of net addresses and hang them off the mount point.
1970  * Called by ufs_mount() to set up the lists of export addresses.
1971  */
1972 static int
1973 vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
1974 		const struct export_args *argp)
1975 {
1976 	struct netcred *np;
1977 	struct radix_node_head *rnh;
1978 	int i;
1979 	struct radix_node *rn;
1980 	struct sockaddr *saddr, *smask = NULL;
1981 	int error;
1982 
1983 	if (argp->ex_addrlen == 0) {
1984 		if (mp->mnt_flag & MNT_DEFEXPORTED)
1985 			return (EPERM);
1986 		np = &nep->ne_defexported;
1987 		np->netc_exflags = argp->ex_flags;
1988 		np->netc_anon = argp->ex_anon;
1989 		np->netc_anon.cr_ref = 1;
1990 		mp->mnt_flag |= MNT_DEFEXPORTED;
1991 		return (0);
1992 	}
1993 
1994 	if (argp->ex_addrlen < 0 || argp->ex_addrlen > MLEN)
1995 		return (EINVAL);
1996 	if (argp->ex_masklen < 0 || argp->ex_masklen > MLEN)
1997 		return (EINVAL);
1998 
1999 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
2000 	np = (struct netcred *) kmalloc(i, M_NETADDR, M_WAITOK | M_ZERO);
2001 	saddr = (struct sockaddr *) (np + 1);
2002 	if ((error = copyin(argp->ex_addr, (caddr_t) saddr, argp->ex_addrlen)))
2003 		goto out;
2004 	if (saddr->sa_len > argp->ex_addrlen)
2005 		saddr->sa_len = argp->ex_addrlen;
2006 	if (argp->ex_masklen) {
2007 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
2008 		error = copyin(argp->ex_mask, (caddr_t)smask, argp->ex_masklen);
2009 		if (error)
2010 			goto out;
2011 		if (smask->sa_len > argp->ex_masklen)
2012 			smask->sa_len = argp->ex_masklen;
2013 	}
2014 	NE_LOCK(nep);
2015 	if (nep->ne_maskhead == NULL) {
2016 		if (!rn_inithead((void **)&nep->ne_maskhead, NULL, 0)) {
2017 			error = ENOBUFS;
2018 			goto out;
2019 		}
2020 	}
2021 	if((rnh = vfs_create_addrlist_af(saddr->sa_family, nep)) == NULL) {
2022 		error = ENOBUFS;
2023 		goto out;
2024 	}
2025 	rn = (*rnh->rnh_addaddr) ((char *) saddr, (char *) smask, rnh,
2026 	    np->netc_rnodes);
2027 	NE_UNLOCK(nep);
2028 	if (rn == NULL || np != (struct netcred *) rn) {	/* already exists */
2029 		error = EPERM;
2030 		goto out;
2031 	}
2032 	np->netc_exflags = argp->ex_flags;
2033 	np->netc_anon = argp->ex_anon;
2034 	np->netc_anon.cr_ref = 1;
2035 	return (0);
2036 out:
2037 	kfree(np, M_NETADDR);
2038 	return (error);
2039 }
2040 
2041 /* ARGSUSED */
2042 static int
2043 vfs_free_netcred(struct radix_node *rn, void *w)
2044 {
2045 	struct radix_node_head *rnh = (struct radix_node_head *) w;
2046 
2047 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
2048 	kfree((caddr_t) rn, M_NETADDR);
2049 	return (0);
2050 }
2051 
2052 static struct radix_node_head *
2053 vfs_create_addrlist_af(int af, struct netexport *nep)
2054 {
2055 	struct radix_node_head *rnh = NULL;
2056 #if defined(INET) || defined(INET6)
2057 	struct radix_node_head *maskhead = nep->ne_maskhead;
2058 	int off;
2059 #endif
2060 
2061 	NE_ASSERT_LOCKED(nep);
2062 	KKASSERT(maskhead != NULL);
2063 	switch (af) {
2064 #ifdef INET
2065 	case AF_INET:
2066 		if ((rnh = nep->ne_inethead) == NULL) {
2067 			off = offsetof(struct sockaddr_in, sin_addr) << 3;
2068 			if (!rn_inithead((void **)&rnh, maskhead, off))
2069 				return (NULL);
2070 			nep->ne_inethead = rnh;
2071 		}
2072 		break;
2073 #endif
2074 #ifdef INET6
2075 	case AF_INET6:
2076 		if ((rnh = nep->ne_inet6head) == NULL) {
2077 			off = offsetof(struct sockaddr_in6, sin6_addr) << 3;
2078 			if (!rn_inithead((void **)&rnh, maskhead, off))
2079 				return (NULL);
2080 			nep->ne_inet6head = rnh;
2081 		}
2082 		break;
2083 #endif
2084 	}
2085 	return (rnh);
2086 }
2087 
2088 static void
2089 vfs_free_addrlist_af(struct radix_node_head **prnh)
2090 {
2091 	struct radix_node_head *rnh = *prnh;
2092 
2093 	(*rnh->rnh_walktree) (rnh, vfs_free_netcred, rnh);
2094 	kfree(rnh, M_RTABLE);
2095 	*prnh = NULL;
2096 }
2097 
2098 /*
2099  * Free the net address hash lists that are hanging off the mount points.
2100  */
2101 static void
2102 vfs_free_addrlist(struct netexport *nep)
2103 {
2104 	NE_LOCK(nep);
2105 	if (nep->ne_inethead != NULL)
2106 		vfs_free_addrlist_af(&nep->ne_inethead);
2107 	if (nep->ne_inet6head != NULL)
2108 		vfs_free_addrlist_af(&nep->ne_inet6head);
2109 	if (nep->ne_maskhead)
2110 		vfs_free_addrlist_af(&nep->ne_maskhead);
2111 	NE_UNLOCK(nep);
2112 }
2113 
2114 int
2115 vfs_export(struct mount *mp, struct netexport *nep,
2116 	   const struct export_args *argp)
2117 {
2118 	int error;
2119 
2120 	if (argp->ex_flags & MNT_DELEXPORT) {
2121 		if (mp->mnt_flag & MNT_EXPUBLIC) {
2122 			vfs_setpublicfs(NULL, NULL, NULL);
2123 			mp->mnt_flag &= ~MNT_EXPUBLIC;
2124 		}
2125 		vfs_free_addrlist(nep);
2126 		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
2127 	}
2128 	if (argp->ex_flags & MNT_EXPORTED) {
2129 		if (argp->ex_flags & MNT_EXPUBLIC) {
2130 			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
2131 				return (error);
2132 			mp->mnt_flag |= MNT_EXPUBLIC;
2133 		}
2134 		if ((error = vfs_hang_addrlist(mp, nep, argp)))
2135 			return (error);
2136 		mp->mnt_flag |= MNT_EXPORTED;
2137 	}
2138 	return (0);
2139 }
2140 
2141 
2142 /*
2143  * Set the publicly exported filesystem (WebNFS). Currently, only
2144  * one public filesystem is possible in the spec (RFC 2054 and 2055)
2145  */
2146 int
2147 vfs_setpublicfs(struct mount *mp, struct netexport *nep,
2148 		const struct export_args *argp)
2149 {
2150 	int error;
2151 	struct vnode *rvp;
2152 	char *cp;
2153 
2154 	/*
2155 	 * mp == NULL -> invalidate the current info, the FS is
2156 	 * no longer exported. May be called from either vfs_export
2157 	 * or unmount, so check if it hasn't already been done.
2158 	 */
2159 	if (mp == NULL) {
2160 		if (nfs_pub.np_valid) {
2161 			nfs_pub.np_valid = 0;
2162 			if (nfs_pub.np_index != NULL) {
2163 				kfree(nfs_pub.np_index, M_TEMP);
2164 				nfs_pub.np_index = NULL;
2165 			}
2166 		}
2167 		return (0);
2168 	}
2169 
2170 	/*
2171 	 * Only one allowed at a time.
2172 	 */
2173 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
2174 		return (EBUSY);
2175 
2176 	/*
2177 	 * Get real filehandle for root of exported FS.
2178 	 */
2179 	bzero((caddr_t)&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
2180 	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
2181 
2182 	if ((error = VFS_ROOT(mp, &rvp)))
2183 		return (error);
2184 
2185 	if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
2186 		return (error);
2187 
2188 	vput(rvp);
2189 
2190 	/*
2191 	 * If an indexfile was specified, pull it in.
2192 	 */
2193 	if (argp->ex_indexfile != NULL) {
2194 		int namelen;
2195 
2196 		error = vn_get_namelen(rvp, &namelen);
2197 		if (error)
2198 			return (error);
2199 		nfs_pub.np_index = kmalloc(namelen, M_TEMP, M_WAITOK);
2200 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
2201 		    namelen, NULL);
2202 		if (!error) {
2203 			/*
2204 			 * Check for illegal filenames.
2205 			 */
2206 			for (cp = nfs_pub.np_index; *cp; cp++) {
2207 				if (*cp == '/') {
2208 					error = EINVAL;
2209 					break;
2210 				}
2211 			}
2212 		}
2213 		if (error) {
2214 			kfree(nfs_pub.np_index, M_TEMP);
2215 			return (error);
2216 		}
2217 	}
2218 
2219 	nfs_pub.np_mount = mp;
2220 	nfs_pub.np_valid = 1;
2221 	return (0);
2222 }
2223 
2224 struct netcred *
2225 vfs_export_lookup(struct mount *mp, struct netexport *nep,
2226 		struct sockaddr *nam)
2227 {
2228 	struct netcred *np;
2229 	struct radix_node_head *rnh;
2230 	struct sockaddr *saddr;
2231 
2232 	np = NULL;
2233 	if (mp->mnt_flag & MNT_EXPORTED) {
2234 		/*
2235 		 * Lookup in the export list first.
2236 		 */
2237 		NE_LOCK(nep);
2238 		if (nam != NULL) {
2239 			saddr = nam;
2240 			switch (saddr->sa_family) {
2241 #ifdef INET
2242 			case AF_INET:
2243 				rnh = nep->ne_inethead;
2244 				break;
2245 #endif
2246 #ifdef INET6
2247 			case AF_INET6:
2248 				rnh = nep->ne_inet6head;
2249 				break;
2250 #endif
2251 			default:
2252 				rnh = NULL;
2253 			}
2254 			if (rnh != NULL) {
2255 				np = (struct netcred *)
2256 					(*rnh->rnh_matchaddr)((char *)saddr,
2257 							      rnh);
2258 				if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
2259 					np = NULL;
2260 			}
2261 		}
2262 		NE_UNLOCK(nep);
2263 		/*
2264 		 * If no address match, use the default if it exists.
2265 		 */
2266 		if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
2267 			np = &nep->ne_defexported;
2268 	}
2269 	return (np);
2270 }
2271 
2272 /*
2273  * perform msync on all vnodes under a mount point.  The mount point must
2274  * be locked.  This code is also responsible for lazy-freeing unreferenced
2275  * vnodes whos VM objects no longer contain pages.
2276  *
2277  * NOTE: MNT_WAIT still skips vnodes in the VXLOCK state.
2278  *
2279  * NOTE: XXX VOP_PUTPAGES and friends requires that the vnode be locked,
2280  * but vnode_pager_putpages() doesn't lock the vnode.  We have to do it
2281  * way up in this high level function.
2282  */
2283 static int vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data);
2284 static int vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data);
2285 
2286 void
2287 vfs_msync(struct mount *mp, int flags)
2288 {
2289 	int vmsc_flags;
2290 
2291 	/*
2292 	 * tmpfs sets this flag to prevent msync(), sync, and the
2293 	 * filesystem periodic syncer from trying to flush VM pages
2294 	 * to swap.  Only pure memory pressure flushes tmpfs VM pages
2295 	 * to swap.
2296 	 */
2297 	if (mp->mnt_kern_flag & MNTK_NOMSYNC)
2298 		return;
2299 
2300 	/*
2301 	 * Ok, scan the vnodes for work.  If the filesystem is using the
2302 	 * syncer thread feature we can use vsyncscan() instead of
2303 	 * vmntvnodescan(), which is much faster.
2304 	 */
2305 	vmsc_flags = VMSC_GETVP;
2306 	if (flags != MNT_WAIT)
2307 		vmsc_flags |= VMSC_NOWAIT;
2308 
2309 	if (mp->mnt_kern_flag & MNTK_THR_SYNC) {
2310 		vsyncscan(mp, vmsc_flags, vfs_msync_scan2,
2311 			  (void *)(intptr_t)flags);
2312 	} else {
2313 		vmntvnodescan(mp, vmsc_flags,
2314 			      vfs_msync_scan1, vfs_msync_scan2,
2315 			      (void *)(intptr_t)flags);
2316 	}
2317 }
2318 
2319 /*
2320  * scan1 is a fast pre-check.  There could be hundreds of thousands of
2321  * vnodes, we cannot afford to do anything heavy weight until we have a
2322  * fairly good indication that there is work to do.
2323  */
2324 static
2325 int
2326 vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data)
2327 {
2328 	int flags = (int)(intptr_t)data;
2329 
2330 	if ((vp->v_flag & VRECLAIMED) == 0) {
2331 		if (vp->v_auxrefs == 0 && VREFCNT(vp) <= 0 &&
2332 		    vp->v_object) {
2333 			return(0);	/* call scan2 */
2334 		}
2335 		if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
2336 		    (vp->v_flag & VOBJDIRTY) &&
2337 		    (flags == MNT_WAIT || vn_islocked(vp) == 0)) {
2338 			return(0);	/* call scan2 */
2339 		}
2340 	}
2341 
2342 	/*
2343 	 * do not call scan2, continue the loop
2344 	 */
2345 	return(-1);
2346 }
2347 
2348 /*
2349  * This callback is handed a locked vnode.
2350  */
2351 static
2352 int
2353 vfs_msync_scan2(struct mount *mp, struct vnode *vp, void *data)
2354 {
2355 	vm_object_t obj;
2356 	int flags = (int)(intptr_t)data;
2357 
2358 	if (vp->v_flag & VRECLAIMED)
2359 		return(0);
2360 
2361 	if ((mp->mnt_flag & MNT_RDONLY) == 0 && (vp->v_flag & VOBJDIRTY)) {
2362 		if ((obj = vp->v_object) != NULL) {
2363 			vm_object_page_clean(obj, 0, 0,
2364 			 flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
2365 		}
2366 	}
2367 	return(0);
2368 }
2369 
2370 /*
2371  * Wake up anyone interested in vp because it is being revoked.
2372  */
2373 void
2374 vn_gone(struct vnode *vp)
2375 {
2376 	lwkt_gettoken(&vp->v_token);
2377 	KNOTE(&vp->v_pollinfo.vpi_kqinfo.ki_note, NOTE_REVOKE);
2378 	lwkt_reltoken(&vp->v_token);
2379 }
2380 
2381 /*
2382  * extract the cdev_t from a VBLK or VCHR.  The vnode must have been opened
2383  * (or v_rdev might be NULL).
2384  */
2385 cdev_t
2386 vn_todev(struct vnode *vp)
2387 {
2388 	if (vp->v_type != VBLK && vp->v_type != VCHR)
2389 		return (NULL);
2390 	KKASSERT(vp->v_rdev != NULL);
2391 	return (vp->v_rdev);
2392 }
2393 
2394 /*
2395  * Check if vnode represents a disk device.  The vnode does not need to be
2396  * opened.
2397  *
2398  * MPALMOSTSAFE
2399  */
2400 int
2401 vn_isdisk(struct vnode *vp, int *errp)
2402 {
2403 	cdev_t dev;
2404 
2405 	if (vp->v_type != VCHR) {
2406 		if (errp != NULL)
2407 			*errp = ENOTBLK;
2408 		return (0);
2409 	}
2410 
2411 	dev = vp->v_rdev;
2412 
2413 	if (dev == NULL) {
2414 		if (errp != NULL)
2415 			*errp = ENXIO;
2416 		return (0);
2417 	}
2418 	if (dev_is_good(dev) == 0) {
2419 		if (errp != NULL)
2420 			*errp = ENXIO;
2421 		return (0);
2422 	}
2423 	if ((dev_dflags(dev) & D_DISK) == 0) {
2424 		if (errp != NULL)
2425 			*errp = ENOTBLK;
2426 		return (0);
2427 	}
2428 	if (errp != NULL)
2429 		*errp = 0;
2430 	return (1);
2431 }
2432 
2433 int
2434 vn_get_namelen(struct vnode *vp, int *namelen)
2435 {
2436 	int error;
2437 	register_t retval[2];
2438 
2439 	error = VOP_PATHCONF(vp, _PC_NAME_MAX, retval);
2440 	if (error)
2441 		return (error);
2442 	*namelen = (int)retval[0];
2443 	return (0);
2444 }
2445 
2446 int
2447 vop_write_dirent(int *error, struct uio *uio, ino_t d_ino, uint8_t d_type,
2448 		uint16_t d_namlen, const char *d_name)
2449 {
2450 	struct dirent *dp;
2451 	size_t len;
2452 
2453 	len = _DIRENT_RECLEN(d_namlen);
2454 	if (len > uio->uio_resid)
2455 		return(1);
2456 
2457 	dp = kmalloc(len, M_TEMP, M_WAITOK | M_ZERO);
2458 
2459 	dp->d_ino = d_ino;
2460 	dp->d_namlen = d_namlen;
2461 	dp->d_type = d_type;
2462 	bcopy(d_name, dp->d_name, d_namlen);
2463 
2464 	*error = uiomove((caddr_t)dp, len, uio);
2465 
2466 	kfree(dp, M_TEMP);
2467 
2468 	return(0);
2469 }
2470 
2471 void
2472 vn_mark_atime(struct vnode *vp, struct thread *td)
2473 {
2474 	struct proc *p = td->td_proc;
2475 	struct ucred *cred = p ? p->p_ucred : proc0.p_ucred;
2476 
2477 	if ((vp->v_mount->mnt_flag & (MNT_NOATIME | MNT_RDONLY)) == 0) {
2478 		VOP_MARKATIME(vp, cred);
2479 	}
2480 }
2481 
2482 /*
2483  * Calculate the number of entries in an inode-related chained hash table.
2484  * With today's memory sizes, maxvnodes can wind up being a very large
2485  * number.  There is no reason to waste memory, so tolerate some stacking.
2486  */
2487 int
2488 vfs_inodehashsize(void)
2489 {
2490 	int hsize;
2491 
2492 	hsize = 32;
2493 	while (hsize < maxvnodes)
2494 		hsize <<= 1;
2495 	while (hsize > maxvnodes * 2)
2496 		hsize >>= 1;		/* nominal 2x stacking */
2497 
2498 	if (maxvnodes > 1024 * 1024)
2499 		hsize >>= 1;		/* nominal 8x stacking */
2500 
2501 	if (maxvnodes > 128 * 1024)
2502 		hsize >>= 1;		/* nominal 4x stacking */
2503 
2504 	if (hsize < 16)
2505 		hsize = 16;
2506 
2507 	return hsize;
2508 }
2509