xref: /dragonfly/sys/kern/vfs_subr.c (revision 86fe9e07)
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 1.37 2004/08/17 18:57:32 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/kernel.h>
57 #include <sys/kthread.h>
58 #include <sys/malloc.h>
59 #include <sys/mbuf.h>
60 #include <sys/mount.h>
61 #include <sys/proc.h>
62 #include <sys/namei.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/vmmeter.h>
69 #include <sys/vnode.h>
70 
71 #include <machine/limits.h>
72 
73 #include <vm/vm.h>
74 #include <vm/vm_object.h>
75 #include <vm/vm_extern.h>
76 #include <vm/vm_kern.h>
77 #include <vm/pmap.h>
78 #include <vm/vm_map.h>
79 #include <vm/vm_page.h>
80 #include <vm/vm_pager.h>
81 #include <vm/vnode_pager.h>
82 #include <vm/vm_zone.h>
83 
84 #include <sys/buf2.h>
85 #include <sys/thread2.h>
86 
87 static MALLOC_DEFINE(M_NETADDR, "Export Host", "Export host address structure");
88 
89 static void	insmntque (struct vnode *vp, struct mount *mp);
90 static void	vclean (struct vnode *vp, lwkt_tokref_t vlock,
91 			int flags, struct thread *td);
92 
93 static unsigned long numvnodes;
94 SYSCTL_INT(_debug, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 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 TAILQ_HEAD(freelst, vnode) vnode_free_list;	/* vnode free list */
106 
107 static u_long wantfreevnodes = 25;
108 SYSCTL_INT(_debug, OID_AUTO, wantfreevnodes, CTLFLAG_RW,
109 		&wantfreevnodes, 0, "");
110 static u_long freevnodes = 0;
111 SYSCTL_INT(_debug, OID_AUTO, freevnodes, CTLFLAG_RD,
112 		&freevnodes, 0, "");
113 
114 static int reassignbufcalls;
115 SYSCTL_INT(_vfs, OID_AUTO, reassignbufcalls, CTLFLAG_RW,
116 		&reassignbufcalls, 0, "");
117 static int reassignbufloops;
118 SYSCTL_INT(_vfs, OID_AUTO, reassignbufloops, CTLFLAG_RW,
119 		&reassignbufloops, 0, "");
120 static int reassignbufsortgood;
121 SYSCTL_INT(_vfs, OID_AUTO, reassignbufsortgood, CTLFLAG_RW,
122 		&reassignbufsortgood, 0, "");
123 static int reassignbufsortbad;
124 SYSCTL_INT(_vfs, OID_AUTO, reassignbufsortbad, CTLFLAG_RW,
125 		&reassignbufsortbad, 0, "");
126 static int reassignbufmethod = 1;
127 SYSCTL_INT(_vfs, OID_AUTO, reassignbufmethod, CTLFLAG_RW,
128 		&reassignbufmethod, 0, "");
129 
130 #ifdef ENABLE_VFS_IOOPT
131 int vfs_ioopt = 0;
132 SYSCTL_INT(_vfs, OID_AUTO, ioopt, CTLFLAG_RW, &vfs_ioopt, 0, "");
133 #endif
134 
135 struct mntlist mountlist = TAILQ_HEAD_INITIALIZER(mountlist); /* mounted fs */
136 struct lwkt_token mountlist_token;
137 struct lwkt_token mntvnode_token;
138 int	nfs_mount_type = -1;
139 static struct lwkt_token mntid_token;
140 static struct lwkt_token vnode_free_list_token;
141 static struct lwkt_token spechash_token;
142 struct nfs_public nfs_pub;	/* publicly exported FS */
143 static vm_zone_t vnode_zone;
144 
145 /*
146  * The workitem queue.
147  */
148 #define SYNCER_MAXDELAY		32
149 static int syncer_maxdelay = SYNCER_MAXDELAY;	/* maximum delay time */
150 time_t syncdelay = 30;		/* max time to delay syncing data */
151 SYSCTL_INT(_kern, OID_AUTO, syncdelay, CTLFLAG_RW,
152 		&syncdelay, 0, "VFS data synchronization delay");
153 time_t filedelay = 30;		/* time to delay syncing files */
154 SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW,
155 		&filedelay, 0, "File synchronization delay");
156 time_t dirdelay = 29;		/* time to delay syncing directories */
157 SYSCTL_INT(_kern, OID_AUTO, dirdelay, CTLFLAG_RW,
158 		&dirdelay, 0, "Directory synchronization delay");
159 time_t metadelay = 28;		/* time to delay syncing metadata */
160 SYSCTL_INT(_kern, OID_AUTO, metadelay, CTLFLAG_RW,
161 		&metadelay, 0, "VFS metadata synchronization delay");
162 static int rushjob;			/* number of slots to run ASAP */
163 static int stat_rush_requests;	/* number of times I/O speeded up */
164 SYSCTL_INT(_debug, OID_AUTO, rush_requests, CTLFLAG_RW,
165 		&stat_rush_requests, 0, "");
166 
167 static int syncer_delayno = 0;
168 static long syncer_mask;
169 LIST_HEAD(synclist, vnode);
170 static struct synclist *syncer_workitem_pending;
171 
172 int desiredvnodes;
173 SYSCTL_INT(_kern, KERN_MAXVNODES, maxvnodes, CTLFLAG_RW,
174 		&desiredvnodes, 0, "Maximum number of vnodes");
175 static int minvnodes;
176 SYSCTL_INT(_kern, OID_AUTO, minvnodes, CTLFLAG_RW,
177 		&minvnodes, 0, "Minimum number of vnodes");
178 static int vnlru_nowhere = 0;
179 SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW,
180 		&vnlru_nowhere, 0,
181 		"Number of times the vnlru process ran without success");
182 
183 static void	vfs_free_addrlist (struct netexport *nep);
184 static int	vfs_free_netcred (struct radix_node *rn, void *w);
185 static int	vfs_hang_addrlist (struct mount *mp, struct netexport *nep,
186 				       struct export_args *argp);
187 
188 #define VSHOULDFREE(vp) \
189 	(!((vp)->v_flag & (VFREE|VDOOMED)) && \
190 	 !(vp)->v_holdcnt && !(vp)->v_usecount && \
191 	 (!(vp)->v_object || \
192 	  !((vp)->v_object->ref_count || (vp)->v_object->resident_page_count)))
193 
194 #define VMIGHTFREE(vp) \
195 	(((vp)->v_flag & (VFREE|VDOOMED|VXLOCK)) == 0 &&   \
196 	 cache_leaf_test(vp) == 0 && (vp)->v_usecount == 0)
197 
198 #define VSHOULDBUSY(vp) \
199 	(((vp)->v_flag & VFREE) && \
200 	 ((vp)->v_holdcnt || (vp)->v_usecount))
201 
202 static void vbusy(struct vnode *vp);
203 static void vfree(struct vnode *vp);
204 static void vmaybefree(struct vnode *vp);
205 
206 extern int dev_ref_debug;
207 extern struct vnodeopv_entry_desc spec_vnodeop_entries[];
208 
209 /*
210  * NOTE: the vnode interlock must be held on call.
211  */
212 static __inline void
213 vmaybefree(struct vnode *vp)
214 {
215 	if (VSHOULDFREE(vp))
216 		vfree(vp);
217 }
218 
219 /*
220  * Initialize the vnode management data structures.
221  */
222 void
223 vntblinit(void)
224 {
225 	/*
226 	 * Desired vnodes is a result of the physical page count
227 	 * and the size of kernel's heap.  It scales in proportion
228 	 * to the amount of available physical memory.  This can
229 	 * cause trouble on 64-bit and large memory platforms.
230 	 */
231 	/* desiredvnodes = maxproc + vmstats.v_page_count / 4; */
232 	desiredvnodes =
233 		min(maxproc + vmstats.v_page_count /4,
234 		    2 * (VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS) /
235 		    (5 * (sizeof(struct vm_object) + sizeof(struct vnode))));
236 
237 	minvnodes = desiredvnodes / 4;
238 	lwkt_token_init(&mountlist_token);
239 	lwkt_token_init(&mntvnode_token);
240 	lwkt_token_init(&mntid_token);
241 	lwkt_token_init(&spechash_token);
242 	TAILQ_INIT(&vnode_free_list);
243 	lwkt_token_init(&vnode_free_list_token);
244 	vnode_zone = zinit("VNODE", sizeof (struct vnode), 0, 0, 5);
245 	/*
246 	 * Initialize the filesystem syncer.
247 	 */
248 	syncer_workitem_pending = hashinit(syncer_maxdelay, M_VNODE,
249 		&syncer_mask);
250 	syncer_maxdelay = syncer_mask + 1;
251 }
252 
253 /*
254  * Mark a mount point as busy. Used to synchronize access and to delay
255  * unmounting. Interlock is not released on failure.
256  */
257 int
258 vfs_busy(struct mount *mp, int flags,
259 	lwkt_tokref_t interlkp, struct thread *td)
260 {
261 	int lkflags;
262 
263 	if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
264 		if (flags & LK_NOWAIT)
265 			return (ENOENT);
266 		mp->mnt_kern_flag |= MNTK_MWAIT;
267 		/*
268 		 * Since all busy locks are shared except the exclusive
269 		 * lock granted when unmounting, the only place that a
270 		 * wakeup needs to be done is at the release of the
271 		 * exclusive lock at the end of dounmount.
272 		 *
273 		 * note: interlkp is a serializer and thus can be safely
274 		 * held through any sleep
275 		 */
276 		tsleep((caddr_t)mp, 0, "vfs_busy", 0);
277 		return (ENOENT);
278 	}
279 	lkflags = LK_SHARED | LK_NOPAUSE;
280 	if (interlkp)
281 		lkflags |= LK_INTERLOCK;
282 	if (lockmgr(&mp->mnt_lock, lkflags, interlkp, td))
283 		panic("vfs_busy: unexpected lock failure");
284 	return (0);
285 }
286 
287 /*
288  * Free a busy filesystem.
289  */
290 void
291 vfs_unbusy(struct mount *mp, struct thread *td)
292 {
293 	lockmgr(&mp->mnt_lock, LK_RELEASE, NULL, td);
294 }
295 
296 /*
297  * Lookup a filesystem type, and if found allocate and initialize
298  * a mount structure for it.
299  *
300  * Devname is usually updated by mount(8) after booting.
301  */
302 int
303 vfs_rootmountalloc(char *fstypename, char *devname, struct mount **mpp)
304 {
305 	struct thread *td = curthread;	/* XXX */
306 	struct vfsconf *vfsp;
307 	struct mount *mp;
308 
309 	if (fstypename == NULL)
310 		return (ENODEV);
311 	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
312 		if (!strcmp(vfsp->vfc_name, fstypename))
313 			break;
314 	}
315 	if (vfsp == NULL)
316 		return (ENODEV);
317 	mp = malloc((u_long)sizeof(struct mount), M_MOUNT, M_WAITOK);
318 	bzero((char *)mp, (u_long)sizeof(struct mount));
319 	lockinit(&mp->mnt_lock, 0, "vfslock", VLKTIMEOUT, LK_NOPAUSE);
320 	vfs_busy(mp, LK_NOWAIT, NULL, td);
321 	TAILQ_INIT(&mp->mnt_nvnodelist);
322 	TAILQ_INIT(&mp->mnt_reservedvnlist);
323 	mp->mnt_nvnodelistsize = 0;
324 	mp->mnt_vfc = vfsp;
325 	mp->mnt_op = vfsp->vfc_vfsops;
326 	mp->mnt_flag = MNT_RDONLY;
327 	mp->mnt_vnodecovered = NULLVP;
328 	vfsp->vfc_refcount++;
329 	mp->mnt_iosize_max = DFLTPHYS;
330 	mp->mnt_stat.f_type = vfsp->vfc_typenum;
331 	mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
332 	strncpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
333 	mp->mnt_stat.f_mntonname[0] = '/';
334 	mp->mnt_stat.f_mntonname[1] = 0;
335 	(void) copystr(devname, mp->mnt_stat.f_mntfromname, MNAMELEN - 1, 0);
336 	*mpp = mp;
337 	return (0);
338 }
339 
340 /*
341  * Lookup a mount point by filesystem identifier.
342  */
343 struct mount *
344 vfs_getvfs(fsid_t *fsid)
345 {
346 	struct mount *mp;
347 	lwkt_tokref ilock;
348 
349 	lwkt_gettoken(&ilock, &mountlist_token);
350 	TAILQ_FOREACH(mp, &mountlist, mnt_list) {
351 		if (mp->mnt_stat.f_fsid.val[0] == fsid->val[0] &&
352 		    mp->mnt_stat.f_fsid.val[1] == fsid->val[1]) {
353 			break;
354 	    }
355 	}
356 	lwkt_reltoken(&ilock);
357 	return (mp);
358 }
359 
360 /*
361  * Get a new unique fsid.  Try to make its val[0] unique, since this value
362  * will be used to create fake device numbers for stat().  Also try (but
363  * not so hard) make its val[0] unique mod 2^16, since some emulators only
364  * support 16-bit device numbers.  We end up with unique val[0]'s for the
365  * first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls.
366  *
367  * Keep in mind that several mounts may be running in parallel.  Starting
368  * the search one past where the previous search terminated is both a
369  * micro-optimization and a defense against returning the same fsid to
370  * different mounts.
371  */
372 void
373 vfs_getnewfsid(struct mount *mp)
374 {
375 	static u_int16_t mntid_base;
376 	lwkt_tokref ilock;
377 	fsid_t tfsid;
378 	int mtype;
379 
380 	lwkt_gettoken(&ilock, &mntid_token);
381 	mtype = mp->mnt_vfc->vfc_typenum;
382 	tfsid.val[1] = mtype;
383 	mtype = (mtype & 0xFF) << 24;
384 	for (;;) {
385 		tfsid.val[0] = makeudev(255,
386 		    mtype | ((mntid_base & 0xFF00) << 8) | (mntid_base & 0xFF));
387 		mntid_base++;
388 		if (vfs_getvfs(&tfsid) == NULL)
389 			break;
390 	}
391 	mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
392 	mp->mnt_stat.f_fsid.val[1] = tfsid.val[1];
393 	lwkt_reltoken(&ilock);
394 }
395 
396 /*
397  * Knob to control the precision of file timestamps:
398  *
399  *   0 = seconds only; nanoseconds zeroed.
400  *   1 = seconds and nanoseconds, accurate within 1/HZ.
401  *   2 = seconds and nanoseconds, truncated to microseconds.
402  * >=3 = seconds and nanoseconds, maximum precision.
403  */
404 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
405 
406 static int timestamp_precision = TSP_SEC;
407 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
408 		&timestamp_precision, 0, "");
409 
410 /*
411  * Get a current timestamp.
412  */
413 void
414 vfs_timestamp(struct timespec *tsp)
415 {
416 	struct timeval tv;
417 
418 	switch (timestamp_precision) {
419 	case TSP_SEC:
420 		tsp->tv_sec = time_second;
421 		tsp->tv_nsec = 0;
422 		break;
423 	case TSP_HZ:
424 		getnanotime(tsp);
425 		break;
426 	case TSP_USEC:
427 		microtime(&tv);
428 		TIMEVAL_TO_TIMESPEC(&tv, tsp);
429 		break;
430 	case TSP_NSEC:
431 	default:
432 		nanotime(tsp);
433 		break;
434 	}
435 }
436 
437 /*
438  * Set vnode attributes to VNOVAL
439  */
440 void
441 vattr_null(struct vattr *vap)
442 {
443 	vap->va_type = VNON;
444 	vap->va_size = VNOVAL;
445 	vap->va_bytes = VNOVAL;
446 	vap->va_mode = VNOVAL;
447 	vap->va_nlink = VNOVAL;
448 	vap->va_uid = VNOVAL;
449 	vap->va_gid = VNOVAL;
450 	vap->va_fsid = VNOVAL;
451 	vap->va_fileid = VNOVAL;
452 	vap->va_blocksize = VNOVAL;
453 	vap->va_rdev = VNOVAL;
454 	vap->va_atime.tv_sec = VNOVAL;
455 	vap->va_atime.tv_nsec = VNOVAL;
456 	vap->va_mtime.tv_sec = VNOVAL;
457 	vap->va_mtime.tv_nsec = VNOVAL;
458 	vap->va_ctime.tv_sec = VNOVAL;
459 	vap->va_ctime.tv_nsec = VNOVAL;
460 	vap->va_flags = VNOVAL;
461 	vap->va_gen = VNOVAL;
462 	vap->va_vaflags = 0;
463 }
464 
465 /*
466  * This routine is called when we have too many vnodes.  It attempts
467  * to free <count> vnodes and will potentially free vnodes that still
468  * have VM backing store (VM backing store is typically the cause
469  * of a vnode blowout so we want to do this).  Therefore, this operation
470  * is not considered cheap.
471  *
472  * A number of conditions may prevent a vnode from being reclaimed.
473  * the buffer cache may have references on the vnode, a directory
474  * vnode may still have references due to the namei cache representing
475  * underlying files, or the vnode may be in active use.   It is not
476  * desireable to reuse such vnodes.  These conditions may cause the
477  * number of vnodes to reach some minimum value regardless of what
478  * you set kern.maxvnodes to.  Do not set kern.maxvnodes too low.
479  */
480 static int
481 vlrureclaim(struct mount *mp)
482 {
483 	struct vnode *vp;
484 	lwkt_tokref ilock;
485 	lwkt_tokref vlock;
486 	int done;
487 	int trigger;
488 	int usevnodes;
489 	int count;
490 
491 	/*
492 	 * Calculate the trigger point, don't allow user
493 	 * screwups to blow us up.   This prevents us from
494 	 * recycling vnodes with lots of resident pages.  We
495 	 * aren't trying to free memory, we are trying to
496 	 * free vnodes.
497 	 */
498 	usevnodes = desiredvnodes;
499 	if (usevnodes <= 0)
500 		usevnodes = 1;
501 	trigger = vmstats.v_page_count * 2 / usevnodes;
502 
503 	done = 0;
504 	lwkt_gettoken(&ilock, &mntvnode_token);
505 	count = mp->mnt_nvnodelistsize / 10 + 1;
506 	while (count && (vp = TAILQ_FIRST(&mp->mnt_nvnodelist)) != NULL) {
507 		/*
508 		 * __VNODESCAN__
509 		 *
510 		 * The VP will stick around while we hold mntvnode_token,
511 		 * at least until we block, so we can safely do an initial
512 		 * check.  But we have to check again after obtaining
513 		 * the vnode interlock.  vp->v_interlock points to stable
514 		 * storage so it's ok if the vp gets ripped out from
515 		 * under us while we are blocked.
516 		 */
517 		if (vp->v_type == VNON ||
518 		    vp->v_type == VBAD ||
519 		    !VMIGHTFREE(vp) ||		/* critical path opt */
520 		    (vp->v_object &&
521 		     vp->v_object->resident_page_count >= trigger)
522 		) {
523 			TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
524 			TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist,vp, v_nmntvnodes);
525 			--count;
526 			continue;
527 		}
528 
529 		/*
530 		 * Get the interlock, delay moving the node to the tail so
531 		 * we don't race against new additions to the mountlist.
532 		 */
533 		lwkt_gettoken(&vlock, vp->v_interlock);
534 		if (TAILQ_FIRST(&mp->mnt_nvnodelist) != vp) {
535 			lwkt_reltoken(&vlock);
536 			continue;
537 		}
538 		TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
539 		TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist,vp, v_nmntvnodes);
540 
541 		/*
542 		 * Must check again
543 		 */
544 		if (vp->v_type == VNON ||
545 		    vp->v_type == VBAD ||
546 		    !VMIGHTFREE(vp) ||		/* critical path opt */
547 		    (vp->v_object &&
548 		     vp->v_object->resident_page_count >= trigger)
549 		) {
550 			lwkt_reltoken(&vlock);
551 			--count;
552 			continue;
553 		}
554 		vgonel(vp, &vlock, curthread);
555 		++done;
556 		--count;
557 	}
558 	lwkt_reltoken(&ilock);
559 	return done;
560 }
561 
562 /*
563  * Attempt to recycle vnodes in a context that is always safe to block.
564  * Calling vlrurecycle() from the bowels of file system code has some
565  * interesting deadlock problems.
566  */
567 static struct thread *vnlruthread;
568 static int vnlruproc_sig;
569 
570 static void
571 vnlru_proc(void)
572 {
573 	struct mount *mp, *nmp;
574 	lwkt_tokref ilock;
575 	int s;
576 	int done;
577 	struct thread *td = curthread;
578 
579 	EVENTHANDLER_REGISTER(shutdown_pre_sync, shutdown_kproc, td,
580 	    SHUTDOWN_PRI_FIRST);
581 
582 	s = splbio();
583 	for (;;) {
584 		kproc_suspend_loop();
585 		if (numvnodes - freevnodes <= desiredvnodes * 9 / 10) {
586 			vnlruproc_sig = 0;
587 			wakeup(&vnlruproc_sig);
588 			tsleep(td, 0, "vlruwt", hz);
589 			continue;
590 		}
591 		done = 0;
592 		lwkt_gettoken(&ilock, &mountlist_token);
593 		for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
594 			if (vfs_busy(mp, LK_NOWAIT, &ilock, td)) {
595 				nmp = TAILQ_NEXT(mp, mnt_list);
596 				continue;
597 			}
598 			done += vlrureclaim(mp);
599 			lwkt_gettokref(&ilock);
600 			nmp = TAILQ_NEXT(mp, mnt_list);
601 			vfs_unbusy(mp, td);
602 		}
603 		lwkt_reltoken(&ilock);
604 		if (done == 0) {
605 			vnlru_nowhere++;
606 			tsleep(td, 0, "vlrup", hz * 3);
607 		}
608 	}
609 	splx(s);
610 }
611 
612 static struct kproc_desc vnlru_kp = {
613 	"vnlru",
614 	vnlru_proc,
615 	&vnlruthread
616 };
617 SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &vnlru_kp)
618 
619 /*
620  * Routines having to do with the management of the vnode table.
621  */
622 
623 /*
624  * Return the next vnode from the free list.
625  */
626 int
627 getnewvnode(enum vtagtype tag, struct mount *mp,
628 	    struct vop_ops *ops, struct vnode **vpp)
629 {
630 	int s;
631 	struct thread *td = curthread;	/* XXX */
632 	struct vnode *vp = NULL;
633 	struct vnode *xvp;
634 	vm_object_t object;
635 	lwkt_tokref ilock;
636 	lwkt_tokref vlock;
637 
638 	s = splbio();	/* YYY remove me */
639 
640 	/*
641 	 * Try to reuse vnodes if we hit the max.  This situation only
642 	 * occurs in certain large-memory (2G+) situations.  We cannot
643 	 * attempt to directly reclaim vnodes due to nasty recursion
644 	 * problems.
645 	 */
646 	while (numvnodes - freevnodes > desiredvnodes) {
647 		if (vnlruproc_sig == 0) {
648 			vnlruproc_sig = 1;	/* avoid unnecessary wakeups */
649 			wakeup(vnlruthread);
650 		}
651 		tsleep(&vnlruproc_sig, 0, "vlruwk", hz);
652 	}
653 
654 
655 	/*
656 	 * Attempt to reuse a vnode already on the free list, allocating
657 	 * a new vnode if we can't find one or if we have not reached a
658 	 * good minimum for good LRU performance.
659 	 */
660 	lwkt_gettoken(&ilock, &vnode_free_list_token);
661 	if (freevnodes >= wantfreevnodes && numvnodes >= minvnodes) {
662 		int count;
663 
664 		for (count = 0; count < freevnodes; count++) {
665 			/*
666 			 * __VNODESCAN__
667 			 *
668 			 * Pull the next vnode off the free list and do some
669 			 * sanity checks.  Note that regardless of how we
670 			 * block, if freevnodes is non-zero there had better
671 			 * be something on the list.
672 			 */
673 			vp = TAILQ_FIRST(&vnode_free_list);
674 			if (vp == NULL)
675 				panic("getnewvnode: free vnode isn't");
676 
677 			/*
678 			 * Move the vnode to the end of the list so other
679 			 * processes do not double-block trying to recycle
680 			 * the same vnode (as an optimization), then get
681 			 * the interlock.
682 			 */
683 			TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
684 			TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
685 
686 			/*
687 			 * Skip vnodes that are in the process of being
688 			 * held or referenced.  Since the act of adding or
689 			 * removing a vnode on the freelist requires a token
690 			 * and may block, the ref count may be adjusted
691 			 * prior to its addition or removal.
692 			 */
693 			if (VSHOULDBUSY(vp)) {
694 				vp = NULL;
695 				continue;
696 			}
697 
698 
699 			/*
700 			 * Obtain the vnode interlock and check that the
701 			 * vnode is still on the free list.
702 			 *
703 			 * This normally devolves into a degenerate case so
704 			 * it is optimal.   Loop up if it isn't.  Note that
705 			 * the vnode could be in the middle of being moved
706 			 * off the free list (the VSHOULDBUSY() check) and
707 			 * must be skipped if so.
708 			 */
709 			lwkt_gettoken(&vlock, vp->v_interlock);
710 			TAILQ_FOREACH_REVERSE(xvp, &vnode_free_list,
711 			    freelst, v_freelist) {
712 				if (vp == xvp)
713 					break;
714 			}
715 			if (vp != xvp || VSHOULDBUSY(vp)) {
716 				vp = NULL;
717 				continue;
718 			}
719 
720 			/*
721 			 * We now safely own the vnode.  If the vnode has
722 			 * an object do not recycle it if its VM object
723 			 * has resident pages or references.
724 			 */
725 			if ((VOP_GETVOBJECT(vp, &object) == 0 &&
726 			    (object->resident_page_count || object->ref_count))
727 			) {
728 				lwkt_reltoken(&vlock);
729 				vp = NULL;
730 				continue;
731 			}
732 
733 			/*
734 			 * We can almost reuse this vnode.  But we don't want
735 			 * to recycle it if the vnode has children in the
736 			 * namecache because that breaks the namecache's
737 			 * path element chain.  (YYY use nc_refs for the
738 			 * check?)
739 			 */
740 			KKASSERT(vp->v_flag & VFREE);
741 			TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
742 
743 			if (TAILQ_FIRST(&vp->v_namecache) == NULL ||
744 			    cache_leaf_test(vp) >= 0) {
745 				/* ok, we can reuse this vnode */
746 				break;
747 			}
748 			lwkt_reltoken(&vlock);
749 			TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
750 			vp = NULL;
751 		}
752 	}
753 
754 	/*
755 	 * If vp is non-NULL we hold it's interlock.
756 	 */
757 	if (vp) {
758 		vp->v_flag |= VDOOMED;
759 		vp->v_flag &= ~VFREE;
760 		freevnodes--;
761 		lwkt_reltoken(&ilock);
762 		cache_purge(vp);	/* YYY may block */
763 		vp->v_lease = NULL;
764 		if (vp->v_type != VBAD) {
765 			vgonel(vp, &vlock, td);
766 		} else {
767 			lwkt_reltoken(&vlock);
768 		}
769 
770 #ifdef INVARIANTS
771 		{
772 			int s;
773 
774 			if (vp->v_data)
775 				panic("cleaned vnode isn't");
776 			s = splbio();
777 			if (vp->v_numoutput)
778 				panic("Clean vnode has pending I/O's");
779 			splx(s);
780 		}
781 #endif
782 		vp->v_flag = 0;
783 		vp->v_lastw = 0;
784 		vp->v_lasta = 0;
785 		vp->v_cstart = 0;
786 		vp->v_clen = 0;
787 		vp->v_socket = 0;
788 		vp->v_writecount = 0;	/* XXX */
789 	} else {
790 		lwkt_reltoken(&ilock);
791 		vp = zalloc(vnode_zone);
792 		bzero(vp, sizeof(*vp));
793 		vp->v_interlock = lwkt_token_pool_get(vp);
794 		lwkt_token_init(&vp->v_pollinfo.vpi_token);
795 		cache_purge(vp);
796 		TAILQ_INIT(&vp->v_namecache);
797 		numvnodes++;
798 	}
799 
800 	TAILQ_INIT(&vp->v_cleanblkhd);
801 	TAILQ_INIT(&vp->v_dirtyblkhd);
802 	vp->v_type = VNON;
803 	vp->v_tag = tag;
804 	vp->v_ops = ops;
805 	*vpp = vp;
806 	vp->v_usecount = 1;
807 	vp->v_data = NULL;
808 	splx(s);
809 
810 	/*
811 	 * Placing the vnode on the mount point's queue makes it visible.
812 	 * We had better already have a ref on it.
813 	 */
814 	insmntque(vp, mp);
815 
816 	vfs_object_create(vp, td);
817 	return (0);
818 }
819 
820 /*
821  * Move a vnode from one mount queue to another.
822  */
823 static void
824 insmntque(struct vnode *vp, struct mount *mp)
825 {
826 	lwkt_tokref ilock;
827 
828 	lwkt_gettoken(&ilock, &mntvnode_token);
829 	/*
830 	 * Delete from old mount point vnode list, if on one.
831 	 */
832 	if (vp->v_mount != NULL) {
833 		KASSERT(vp->v_mount->mnt_nvnodelistsize > 0,
834 			("bad mount point vnode list size"));
835 		TAILQ_REMOVE(&vp->v_mount->mnt_nvnodelist, vp, v_nmntvnodes);
836 		vp->v_mount->mnt_nvnodelistsize--;
837 	}
838 	/*
839 	 * Insert into list of vnodes for the new mount point, if available.
840 	 */
841 	if ((vp->v_mount = mp) == NULL) {
842 		lwkt_reltoken(&ilock);
843 		return;
844 	}
845 	TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
846 	mp->mnt_nvnodelistsize++;
847 	lwkt_reltoken(&ilock);
848 }
849 
850 /*
851  * Update outstanding I/O count and do wakeup if requested.
852  */
853 void
854 vwakeup(struct buf *bp)
855 {
856 	struct vnode *vp;
857 
858 	bp->b_flags &= ~B_WRITEINPROG;
859 	if ((vp = bp->b_vp)) {
860 		vp->v_numoutput--;
861 		if (vp->v_numoutput < 0)
862 			panic("vwakeup: neg numoutput");
863 		if ((vp->v_numoutput == 0) && (vp->v_flag & VBWAIT)) {
864 			vp->v_flag &= ~VBWAIT;
865 			wakeup((caddr_t) &vp->v_numoutput);
866 		}
867 	}
868 }
869 
870 /*
871  * Flush out and invalidate all buffers associated with a vnode.
872  * Called with the underlying object locked.
873  */
874 int
875 vinvalbuf(struct vnode *vp, int flags, struct thread *td,
876 	int slpflag, int slptimeo)
877 {
878 	struct buf *bp;
879 	struct buf *nbp, *blist;
880 	int s, error;
881 	vm_object_t object;
882 	lwkt_tokref vlock;
883 
884 	if (flags & V_SAVE) {
885 		s = splbio();
886 		while (vp->v_numoutput) {
887 			vp->v_flag |= VBWAIT;
888 			error = tsleep((caddr_t)&vp->v_numoutput,
889 			    slpflag, "vinvlbuf", slptimeo);
890 			if (error) {
891 				splx(s);
892 				return (error);
893 			}
894 		}
895 		if (!TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
896 			splx(s);
897 			if ((error = VOP_FSYNC(vp, MNT_WAIT, td)) != 0)
898 				return (error);
899 			s = splbio();
900 			if (vp->v_numoutput > 0 ||
901 			    !TAILQ_EMPTY(&vp->v_dirtyblkhd))
902 				panic("vinvalbuf: dirty bufs");
903 		}
904 		splx(s);
905   	}
906 	s = splbio();
907 	for (;;) {
908 		blist = TAILQ_FIRST(&vp->v_cleanblkhd);
909 		if (!blist)
910 			blist = TAILQ_FIRST(&vp->v_dirtyblkhd);
911 		if (!blist)
912 			break;
913 
914 		for (bp = blist; bp; bp = nbp) {
915 			nbp = TAILQ_NEXT(bp, b_vnbufs);
916 			if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
917 				error = BUF_TIMELOCK(bp,
918 				    LK_EXCLUSIVE | LK_SLEEPFAIL,
919 				    "vinvalbuf", slpflag, slptimeo);
920 				if (error == ENOLCK)
921 					break;
922 				splx(s);
923 				return (error);
924 			}
925 			/*
926 			 * XXX Since there are no node locks for NFS, I
927 			 * believe there is a slight chance that a delayed
928 			 * write will occur while sleeping just above, so
929 			 * check for it.  Note that vfs_bio_awrite expects
930 			 * buffers to reside on a queue, while VOP_BWRITE and
931 			 * brelse do not.
932 			 */
933 			if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
934 				(flags & V_SAVE)) {
935 
936 				if (bp->b_vp == vp) {
937 					if (bp->b_flags & B_CLUSTEROK) {
938 						BUF_UNLOCK(bp);
939 						vfs_bio_awrite(bp);
940 					} else {
941 						bremfree(bp);
942 						bp->b_flags |= B_ASYNC;
943 						VOP_BWRITE(bp->b_vp, bp);
944 					}
945 				} else {
946 					bremfree(bp);
947 					(void) VOP_BWRITE(bp->b_vp, bp);
948 				}
949 				break;
950 			}
951 			bremfree(bp);
952 			bp->b_flags |= (B_INVAL | B_NOCACHE | B_RELBUF);
953 			bp->b_flags &= ~B_ASYNC;
954 			brelse(bp);
955 		}
956 	}
957 
958 	/*
959 	 * Wait for I/O to complete.  XXX needs cleaning up.  The vnode can
960 	 * have write I/O in-progress but if there is a VM object then the
961 	 * VM object can also have read-I/O in-progress.
962 	 */
963 	do {
964 		while (vp->v_numoutput > 0) {
965 			vp->v_flag |= VBWAIT;
966 			tsleep(&vp->v_numoutput, 0, "vnvlbv", 0);
967 		}
968 		if (VOP_GETVOBJECT(vp, &object) == 0) {
969 			while (object->paging_in_progress)
970 				vm_object_pip_sleep(object, "vnvlbx");
971 		}
972 	} while (vp->v_numoutput > 0);
973 
974 	splx(s);
975 
976 	/*
977 	 * Destroy the copy in the VM cache, too.
978 	 */
979 	lwkt_gettoken(&vlock, vp->v_interlock);
980 	if (VOP_GETVOBJECT(vp, &object) == 0) {
981 		vm_object_page_remove(object, 0, 0,
982 			(flags & V_SAVE) ? TRUE : FALSE);
983 	}
984 	lwkt_reltoken(&vlock);
985 
986 	if (!TAILQ_EMPTY(&vp->v_dirtyblkhd) || !TAILQ_EMPTY(&vp->v_cleanblkhd))
987 		panic("vinvalbuf: flush failed");
988 	return (0);
989 }
990 
991 /*
992  * Truncate a file's buffer and pages to a specified length.  This
993  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
994  * sync activity.
995  */
996 int
997 vtruncbuf(struct vnode *vp, struct thread *td, off_t length, int blksize)
998 {
999 	struct buf *bp;
1000 	struct buf *nbp;
1001 	int s, anyfreed;
1002 	int trunclbn;
1003 
1004 	/*
1005 	 * Round up to the *next* lbn.
1006 	 */
1007 	trunclbn = (length + blksize - 1) / blksize;
1008 
1009 	s = splbio();
1010 restart:
1011 	anyfreed = 1;
1012 	for (;anyfreed;) {
1013 		anyfreed = 0;
1014 		for (bp = TAILQ_FIRST(&vp->v_cleanblkhd); bp; bp = nbp) {
1015 			nbp = TAILQ_NEXT(bp, b_vnbufs);
1016 			if (bp->b_lblkno >= trunclbn) {
1017 				if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
1018 					BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL);
1019 					goto restart;
1020 				} else {
1021 					bremfree(bp);
1022 					bp->b_flags |= (B_INVAL | B_RELBUF);
1023 					bp->b_flags &= ~B_ASYNC;
1024 					brelse(bp);
1025 					anyfreed = 1;
1026 				}
1027 				if (nbp &&
1028 				    (((nbp->b_xflags & BX_VNCLEAN) == 0) ||
1029 				    (nbp->b_vp != vp) ||
1030 				    (nbp->b_flags & B_DELWRI))) {
1031 					goto restart;
1032 				}
1033 			}
1034 		}
1035 
1036 		for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
1037 			nbp = TAILQ_NEXT(bp, b_vnbufs);
1038 			if (bp->b_lblkno >= trunclbn) {
1039 				if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
1040 					BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL);
1041 					goto restart;
1042 				} else {
1043 					bremfree(bp);
1044 					bp->b_flags |= (B_INVAL | B_RELBUF);
1045 					bp->b_flags &= ~B_ASYNC;
1046 					brelse(bp);
1047 					anyfreed = 1;
1048 				}
1049 				if (nbp &&
1050 				    (((nbp->b_xflags & BX_VNDIRTY) == 0) ||
1051 				    (nbp->b_vp != vp) ||
1052 				    (nbp->b_flags & B_DELWRI) == 0)) {
1053 					goto restart;
1054 				}
1055 			}
1056 		}
1057 	}
1058 
1059 	if (length > 0) {
1060 restartsync:
1061 		for (bp = TAILQ_FIRST(&vp->v_dirtyblkhd); bp; bp = nbp) {
1062 			nbp = TAILQ_NEXT(bp, b_vnbufs);
1063 			if ((bp->b_flags & B_DELWRI) && (bp->b_lblkno < 0)) {
1064 				if (BUF_LOCK(bp, LK_EXCLUSIVE | LK_NOWAIT)) {
1065 					BUF_LOCK(bp, LK_EXCLUSIVE|LK_SLEEPFAIL);
1066 					goto restart;
1067 				} else {
1068 					bremfree(bp);
1069 					if (bp->b_vp == vp) {
1070 						bp->b_flags |= B_ASYNC;
1071 					} else {
1072 						bp->b_flags &= ~B_ASYNC;
1073 					}
1074 					VOP_BWRITE(bp->b_vp, bp);
1075 				}
1076 				goto restartsync;
1077 			}
1078 
1079 		}
1080 	}
1081 
1082 	while (vp->v_numoutput > 0) {
1083 		vp->v_flag |= VBWAIT;
1084 		tsleep(&vp->v_numoutput, 0, "vbtrunc", 0);
1085 	}
1086 
1087 	splx(s);
1088 
1089 	vnode_pager_setsize(vp, length);
1090 
1091 	return (0);
1092 }
1093 
1094 /*
1095  * Associate a buffer with a vnode.
1096  */
1097 void
1098 bgetvp(struct vnode *vp, struct buf *bp)
1099 {
1100 	int s;
1101 
1102 	KASSERT(bp->b_vp == NULL, ("bgetvp: not free"));
1103 
1104 	vhold(vp);
1105 	bp->b_vp = vp;
1106 	bp->b_dev = vn_todev(vp);
1107 	/*
1108 	 * Insert onto list for new vnode.
1109 	 */
1110 	s = splbio();
1111 	bp->b_xflags |= BX_VNCLEAN;
1112 	bp->b_xflags &= ~BX_VNDIRTY;
1113 	TAILQ_INSERT_TAIL(&vp->v_cleanblkhd, bp, b_vnbufs);
1114 	splx(s);
1115 }
1116 
1117 /*
1118  * Disassociate a buffer from a vnode.
1119  */
1120 void
1121 brelvp(struct buf *bp)
1122 {
1123 	struct vnode *vp;
1124 	struct buflists *listheadp;
1125 	int s;
1126 
1127 	KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
1128 
1129 	/*
1130 	 * Delete from old vnode list, if on one.
1131 	 */
1132 	vp = bp->b_vp;
1133 	s = splbio();
1134 	if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) {
1135 		if (bp->b_xflags & BX_VNDIRTY)
1136 			listheadp = &vp->v_dirtyblkhd;
1137 		else
1138 			listheadp = &vp->v_cleanblkhd;
1139 		TAILQ_REMOVE(listheadp, bp, b_vnbufs);
1140 		bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
1141 	}
1142 	if ((vp->v_flag & VONWORKLST) && TAILQ_EMPTY(&vp->v_dirtyblkhd)) {
1143 		vp->v_flag &= ~VONWORKLST;
1144 		LIST_REMOVE(vp, v_synclist);
1145 	}
1146 	splx(s);
1147 	bp->b_vp = (struct vnode *) 0;
1148 	vdrop(vp);
1149 }
1150 
1151 /*
1152  * The workitem queue.
1153  *
1154  * It is useful to delay writes of file data and filesystem metadata
1155  * for tens of seconds so that quickly created and deleted files need
1156  * not waste disk bandwidth being created and removed. To realize this,
1157  * we append vnodes to a "workitem" queue. When running with a soft
1158  * updates implementation, most pending metadata dependencies should
1159  * not wait for more than a few seconds. Thus, mounted on block devices
1160  * are delayed only about a half the time that file data is delayed.
1161  * Similarly, directory updates are more critical, so are only delayed
1162  * about a third the time that file data is delayed. Thus, there are
1163  * SYNCER_MAXDELAY queues that are processed round-robin at a rate of
1164  * one each second (driven off the filesystem syncer process). The
1165  * syncer_delayno variable indicates the next queue that is to be processed.
1166  * Items that need to be processed soon are placed in this queue:
1167  *
1168  *	syncer_workitem_pending[syncer_delayno]
1169  *
1170  * A delay of fifteen seconds is done by placing the request fifteen
1171  * entries later in the queue:
1172  *
1173  *	syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
1174  *
1175  */
1176 
1177 /*
1178  * Add an item to the syncer work queue.
1179  */
1180 static void
1181 vn_syncer_add_to_worklist(struct vnode *vp, int delay)
1182 {
1183 	int s, slot;
1184 
1185 	s = splbio();
1186 
1187 	if (vp->v_flag & VONWORKLST) {
1188 		LIST_REMOVE(vp, v_synclist);
1189 	}
1190 
1191 	if (delay > syncer_maxdelay - 2)
1192 		delay = syncer_maxdelay - 2;
1193 	slot = (syncer_delayno + delay) & syncer_mask;
1194 
1195 	LIST_INSERT_HEAD(&syncer_workitem_pending[slot], vp, v_synclist);
1196 	vp->v_flag |= VONWORKLST;
1197 	splx(s);
1198 }
1199 
1200 struct  thread *updatethread;
1201 static void sched_sync (void);
1202 static struct kproc_desc up_kp = {
1203 	"syncer",
1204 	sched_sync,
1205 	&updatethread
1206 };
1207 SYSINIT(syncer, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp)
1208 
1209 /*
1210  * System filesystem synchronizer daemon.
1211  */
1212 void
1213 sched_sync(void)
1214 {
1215 	struct synclist *slp;
1216 	struct vnode *vp;
1217 	long starttime;
1218 	int s;
1219 	struct thread *td = curthread;
1220 
1221 	EVENTHANDLER_REGISTER(shutdown_pre_sync, shutdown_kproc, td,
1222 	    SHUTDOWN_PRI_LAST);
1223 
1224 	for (;;) {
1225 		kproc_suspend_loop();
1226 
1227 		starttime = time_second;
1228 
1229 		/*
1230 		 * Push files whose dirty time has expired.  Be careful
1231 		 * of interrupt race on slp queue.
1232 		 */
1233 		s = splbio();
1234 		slp = &syncer_workitem_pending[syncer_delayno];
1235 		syncer_delayno += 1;
1236 		if (syncer_delayno == syncer_maxdelay)
1237 			syncer_delayno = 0;
1238 		splx(s);
1239 
1240 		while ((vp = LIST_FIRST(slp)) != NULL) {
1241 			if (VOP_ISLOCKED(vp, NULL) == 0) {
1242 				vn_lock(vp, NULL, LK_EXCLUSIVE | LK_RETRY, td);
1243 				(void) VOP_FSYNC(vp, MNT_LAZY, td);
1244 				VOP_UNLOCK(vp, NULL, 0, td);
1245 			}
1246 			s = splbio();
1247 			if (LIST_FIRST(slp) == vp) {
1248 				/*
1249 				 * Note: v_tag VT_VFS vps can remain on the
1250 				 * worklist too with no dirty blocks, but
1251 				 * since sync_fsync() moves it to a different
1252 				 * slot we are safe.
1253 				 */
1254 				if (TAILQ_EMPTY(&vp->v_dirtyblkhd) &&
1255 				    !vn_isdisk(vp, NULL))
1256 					panic("sched_sync: fsync failed vp %p tag %d", vp, vp->v_tag);
1257 				/*
1258 				 * Put us back on the worklist.  The worklist
1259 				 * routine will remove us from our current
1260 				 * position and then add us back in at a later
1261 				 * position.
1262 				 */
1263 				vn_syncer_add_to_worklist(vp, syncdelay);
1264 			}
1265 			splx(s);
1266 		}
1267 
1268 		/*
1269 		 * Do soft update processing.
1270 		 */
1271 		if (bioops.io_sync)
1272 			(*bioops.io_sync)(NULL);
1273 
1274 		/*
1275 		 * The variable rushjob allows the kernel to speed up the
1276 		 * processing of the filesystem syncer process. A rushjob
1277 		 * value of N tells the filesystem syncer to process the next
1278 		 * N seconds worth of work on its queue ASAP. Currently rushjob
1279 		 * is used by the soft update code to speed up the filesystem
1280 		 * syncer process when the incore state is getting so far
1281 		 * ahead of the disk that the kernel memory pool is being
1282 		 * threatened with exhaustion.
1283 		 */
1284 		if (rushjob > 0) {
1285 			rushjob -= 1;
1286 			continue;
1287 		}
1288 		/*
1289 		 * If it has taken us less than a second to process the
1290 		 * current work, then wait. Otherwise start right over
1291 		 * again. We can still lose time if any single round
1292 		 * takes more than two seconds, but it does not really
1293 		 * matter as we are just trying to generally pace the
1294 		 * filesystem activity.
1295 		 */
1296 		if (time_second == starttime)
1297 			tsleep(&lbolt, 0, "syncer", 0);
1298 	}
1299 }
1300 
1301 /*
1302  * Request the syncer daemon to speed up its work.
1303  * We never push it to speed up more than half of its
1304  * normal turn time, otherwise it could take over the cpu.
1305  *
1306  * YYY wchan field protected by the BGL.
1307  */
1308 int
1309 speedup_syncer(void)
1310 {
1311 	crit_enter();
1312 	if (updatethread->td_wchan == &lbolt) { /* YYY */
1313 		unsleep(updatethread);
1314 		lwkt_schedule(updatethread);
1315 	}
1316 	crit_exit();
1317 	if (rushjob < syncdelay / 2) {
1318 		rushjob += 1;
1319 		stat_rush_requests += 1;
1320 		return (1);
1321 	}
1322 	return(0);
1323 }
1324 
1325 /*
1326  * Associate a p-buffer with a vnode.
1327  *
1328  * Also sets B_PAGING flag to indicate that vnode is not fully associated
1329  * with the buffer.  i.e. the bp has not been linked into the vnode or
1330  * ref-counted.
1331  */
1332 void
1333 pbgetvp(struct vnode *vp, struct buf *bp)
1334 {
1335 	KASSERT(bp->b_vp == NULL, ("pbgetvp: not free"));
1336 
1337 	bp->b_vp = vp;
1338 	bp->b_flags |= B_PAGING;
1339 	bp->b_dev = vn_todev(vp);
1340 }
1341 
1342 /*
1343  * Disassociate a p-buffer from a vnode.
1344  */
1345 void
1346 pbrelvp(struct buf *bp)
1347 {
1348 	KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL"));
1349 
1350 	/* XXX REMOVE ME */
1351 	if (TAILQ_NEXT(bp, b_vnbufs) != NULL) {
1352 		panic(
1353 		    "relpbuf(): b_vp was probably reassignbuf()d %p %x",
1354 		    bp,
1355 		    (int)bp->b_flags
1356 		);
1357 	}
1358 	bp->b_vp = (struct vnode *) 0;
1359 	bp->b_flags &= ~B_PAGING;
1360 }
1361 
1362 void
1363 pbreassignbuf(struct buf *bp, struct vnode *newvp)
1364 {
1365 	if ((bp->b_flags & B_PAGING) == 0) {
1366 		panic(
1367 		    "pbreassignbuf() on non phys bp %p",
1368 		    bp
1369 		);
1370 	}
1371 	bp->b_vp = newvp;
1372 }
1373 
1374 /*
1375  * Reassign a buffer from one vnode to another.
1376  * Used to assign file specific control information
1377  * (indirect blocks) to the vnode to which they belong.
1378  */
1379 void
1380 reassignbuf(struct buf *bp, struct vnode *newvp)
1381 {
1382 	struct buflists *listheadp;
1383 	int delay;
1384 	int s;
1385 
1386 	if (newvp == NULL) {
1387 		printf("reassignbuf: NULL");
1388 		return;
1389 	}
1390 	++reassignbufcalls;
1391 
1392 	/*
1393 	 * B_PAGING flagged buffers cannot be reassigned because their vp
1394 	 * is not fully linked in.
1395 	 */
1396 	if (bp->b_flags & B_PAGING)
1397 		panic("cannot reassign paging buffer");
1398 
1399 	s = splbio();
1400 	/*
1401 	 * Delete from old vnode list, if on one.
1402 	 */
1403 	if (bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) {
1404 		if (bp->b_xflags & BX_VNDIRTY)
1405 			listheadp = &bp->b_vp->v_dirtyblkhd;
1406 		else
1407 			listheadp = &bp->b_vp->v_cleanblkhd;
1408 		TAILQ_REMOVE(listheadp, bp, b_vnbufs);
1409 		bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
1410 		if (bp->b_vp != newvp) {
1411 			vdrop(bp->b_vp);
1412 			bp->b_vp = NULL;	/* for clarification */
1413 		}
1414 	}
1415 	/*
1416 	 * If dirty, put on list of dirty buffers; otherwise insert onto list
1417 	 * of clean buffers.
1418 	 */
1419 	if (bp->b_flags & B_DELWRI) {
1420 		struct buf *tbp;
1421 
1422 		listheadp = &newvp->v_dirtyblkhd;
1423 		if ((newvp->v_flag & VONWORKLST) == 0) {
1424 			switch (newvp->v_type) {
1425 			case VDIR:
1426 				delay = dirdelay;
1427 				break;
1428 			case VCHR:
1429 			case VBLK:
1430 				if (newvp->v_rdev &&
1431 				    newvp->v_rdev->si_mountpoint != NULL) {
1432 					delay = metadelay;
1433 					break;
1434 				}
1435 				/* fall through */
1436 			default:
1437 				delay = filedelay;
1438 			}
1439 			vn_syncer_add_to_worklist(newvp, delay);
1440 		}
1441 		bp->b_xflags |= BX_VNDIRTY;
1442 		tbp = TAILQ_FIRST(listheadp);
1443 		if (tbp == NULL ||
1444 		    bp->b_lblkno == 0 ||
1445 		    (bp->b_lblkno > 0 && tbp->b_lblkno < 0) ||
1446 		    (bp->b_lblkno > 0 && bp->b_lblkno < tbp->b_lblkno)) {
1447 			TAILQ_INSERT_HEAD(listheadp, bp, b_vnbufs);
1448 			++reassignbufsortgood;
1449 		} else if (bp->b_lblkno < 0) {
1450 			TAILQ_INSERT_TAIL(listheadp, bp, b_vnbufs);
1451 			++reassignbufsortgood;
1452 		} else if (reassignbufmethod == 1) {
1453 			/*
1454 			 * New sorting algorithm, only handle sequential case,
1455 			 * otherwise append to end (but before metadata)
1456 			 */
1457 			if ((tbp = gbincore(newvp, bp->b_lblkno - 1)) != NULL &&
1458 			    (tbp->b_xflags & BX_VNDIRTY)) {
1459 				/*
1460 				 * Found the best place to insert the buffer
1461 				 */
1462 				TAILQ_INSERT_AFTER(listheadp, tbp, bp, b_vnbufs);
1463 				++reassignbufsortgood;
1464 			} else {
1465 				/*
1466 				 * Missed, append to end, but before meta-data.
1467 				 * We know that the head buffer in the list is
1468 				 * not meta-data due to prior conditionals.
1469 				 *
1470 				 * Indirect effects:  NFS second stage write
1471 				 * tends to wind up here, giving maximum
1472 				 * distance between the unstable write and the
1473 				 * commit rpc.
1474 				 */
1475 				tbp = TAILQ_LAST(listheadp, buflists);
1476 				while (tbp && tbp->b_lblkno < 0)
1477 					tbp = TAILQ_PREV(tbp, buflists, b_vnbufs);
1478 				TAILQ_INSERT_AFTER(listheadp, tbp, bp, b_vnbufs);
1479 				++reassignbufsortbad;
1480 			}
1481 		} else {
1482 			/*
1483 			 * Old sorting algorithm, scan queue and insert
1484 			 */
1485 			struct buf *ttbp;
1486 			while ((ttbp = TAILQ_NEXT(tbp, b_vnbufs)) &&
1487 			    (ttbp->b_lblkno < bp->b_lblkno)) {
1488 				++reassignbufloops;
1489 				tbp = ttbp;
1490 			}
1491 			TAILQ_INSERT_AFTER(listheadp, tbp, bp, b_vnbufs);
1492 		}
1493 	} else {
1494 		bp->b_xflags |= BX_VNCLEAN;
1495 		TAILQ_INSERT_TAIL(&newvp->v_cleanblkhd, bp, b_vnbufs);
1496 		if ((newvp->v_flag & VONWORKLST) &&
1497 		    TAILQ_EMPTY(&newvp->v_dirtyblkhd)) {
1498 			newvp->v_flag &= ~VONWORKLST;
1499 			LIST_REMOVE(newvp, v_synclist);
1500 		}
1501 	}
1502 	if (bp->b_vp != newvp) {
1503 		bp->b_vp = newvp;
1504 		vhold(bp->b_vp);
1505 	}
1506 	splx(s);
1507 }
1508 
1509 /*
1510  * Create a vnode for a block device.
1511  * Used for mounting the root file system.
1512  */
1513 int
1514 bdevvp(dev_t dev, struct vnode **vpp)
1515 {
1516 	struct vnode *vp;
1517 	struct vnode *nvp;
1518 	int error;
1519 
1520 	if (dev == NODEV) {
1521 		*vpp = NULLVP;
1522 		return (ENXIO);
1523 	}
1524 	error = getnewvnode(VT_NON, (struct mount *)0, spec_vnode_vops, &nvp);
1525 	if (error) {
1526 		*vpp = NULLVP;
1527 		return (error);
1528 	}
1529 	vp = nvp;
1530 	vp->v_type = VCHR;
1531 	vp->v_udev = dev->si_udev;
1532 	*vpp = vp;
1533 	return (0);
1534 }
1535 
1536 int
1537 v_associate_rdev(struct vnode *vp, dev_t dev)
1538 {
1539 	lwkt_tokref ilock;
1540 
1541 	if (dev == NULL || dev == NODEV)
1542 		return(ENXIO);
1543 	if (dev_is_good(dev) == 0)
1544 		return(ENXIO);
1545 	KKASSERT(vp->v_rdev == NULL);
1546 	if (dev_ref_debug)
1547 		printf("Z1");
1548 	vp->v_rdev = reference_dev(dev);
1549 	lwkt_gettoken(&ilock, &spechash_token);
1550 	SLIST_INSERT_HEAD(&dev->si_hlist, vp, v_specnext);
1551 	lwkt_reltoken(&ilock);
1552 	return(0);
1553 }
1554 
1555 void
1556 v_release_rdev(struct vnode *vp)
1557 {
1558 	lwkt_tokref ilock;
1559 	dev_t dev;
1560 
1561 	if ((dev = vp->v_rdev) != NULL) {
1562 		lwkt_gettoken(&ilock, &spechash_token);
1563 		SLIST_REMOVE(&dev->si_hlist, vp, vnode, v_specnext);
1564 		if (dev_ref_debug && vp->v_opencount != 0) {
1565 			printf("releasing rdev with non-0 "
1566 				"v_opencount(%d) (revoked?)\n",
1567 				vp->v_opencount);
1568 		}
1569 		vp->v_rdev = NULL;
1570 		vp->v_opencount = 0;
1571 		release_dev(dev);
1572 		lwkt_reltoken(&ilock);
1573 	}
1574 }
1575 
1576 /*
1577  * Add a vnode to the alias list hung off the dev_t.  We only associate
1578  * the device number with the vnode.  The actual device is not associated
1579  * until the vnode is opened (usually in spec_open()), and will be
1580  * disassociated on last close.
1581  */
1582 void
1583 addaliasu(struct vnode *nvp, udev_t nvp_udev)
1584 {
1585 	if (nvp->v_type != VBLK && nvp->v_type != VCHR)
1586 		panic("addaliasu on non-special vnode");
1587 	nvp->v_udev = nvp_udev;
1588 }
1589 
1590 /*
1591  * Grab a particular vnode from the free list, increment its
1592  * reference count and lock it. The vnode lock bit is set if the
1593  * vnode is being eliminated in vgone. The process is awakened
1594  * when the transition is completed, and an error returned to
1595  * indicate that the vnode is no longer usable (possibly having
1596  * been changed to a new file system type).
1597  *
1598  * This code is very sensitive.  We are depending on the vnode interlock
1599  * to be maintained through to the vn_lock() call, which means that we
1600  * cannot block which means that we cannot call vbusy() until after vn_lock().
1601  * If the interlock is not maintained, the VXLOCK check will not properly
1602  * interlock against a vclean()'s LK_DRAIN operation on the lock.
1603  */
1604 int
1605 vget(struct vnode *vp, lwkt_tokref_t vlock, int flags, thread_t td)
1606 {
1607 	int error;
1608 	lwkt_tokref vvlock;
1609 
1610 	/*
1611 	 * We need the interlock to safely modify the v_ fields.  ZZZ it is
1612 	 * only legal to pass (1) the vnode's interlock and (2) only pass
1613 	 * NULL w/o LK_INTERLOCK if the vnode is *ALREADY* referenced or
1614 	 * held.
1615 	 */
1616 	if ((flags & LK_INTERLOCK) == 0) {
1617 		lwkt_gettoken(&vvlock, vp->v_interlock);
1618 		vlock = &vvlock;
1619 	}
1620 
1621 	/*
1622 	 * If the vnode is in the process of being cleaned out for
1623 	 * another use, we wait for the cleaning to finish and then
1624 	 * return failure. Cleaning is determined by checking that
1625 	 * the VXLOCK flag is set.  It is possible for the vnode to be
1626 	 * self-referenced during the cleaning operation.
1627 	 */
1628 	if (vp->v_flag & VXLOCK) {
1629 		if (vp->v_vxthread == curthread) {
1630 #if 0
1631 			/* this can now occur in normal operation */
1632 			log(LOG_INFO, "VXLOCK interlock avoided\n");
1633 #endif
1634 		} else {
1635 			vp->v_flag |= VXWANT;
1636 			lwkt_reltoken(vlock);
1637 			tsleep((caddr_t)vp, 0, "vget", 0);
1638 			return (ENOENT);
1639 		}
1640 	}
1641 
1642 	/*
1643 	 * Bump v_usecount to prevent the vnode from being recycled.  The
1644 	 * usecount needs to be bumped before we successfully get our lock.
1645 	 */
1646 	vp->v_usecount++;
1647 	if (flags & LK_TYPE_MASK) {
1648 		if ((error = vn_lock(vp, vlock, flags | LK_INTERLOCK, td)) != 0) {
1649 			/*
1650 			 * must expand vrele here because we do not want
1651 			 * to call VOP_INACTIVE if the reference count
1652 			 * drops back to zero since it was never really
1653 			 * active. We must remove it from the free list
1654 			 * before sleeping so that multiple processes do
1655 			 * not try to recycle it.
1656 			 */
1657 			lwkt_gettokref(vlock);
1658 			vp->v_usecount--;
1659 			vmaybefree(vp);
1660 			lwkt_reltoken(vlock);
1661 		}
1662 		return (error);
1663 	}
1664 	if (VSHOULDBUSY(vp))
1665 		vbusy(vp);	/* interlock must be held on call */
1666 	lwkt_reltoken(vlock);
1667 	return (0);
1668 }
1669 
1670 void
1671 vref(struct vnode *vp)
1672 {
1673 	crit_enter();	/* YYY use crit section for moment / BGL protected */
1674 	vp->v_usecount++;
1675 	crit_exit();
1676 }
1677 
1678 /*
1679  * Vnode put/release.
1680  * If count drops to zero, call inactive routine and return to freelist.
1681  */
1682 void
1683 vrele(struct vnode *vp)
1684 {
1685 	struct thread *td = curthread;	/* XXX */
1686 	lwkt_tokref vlock;
1687 
1688 	KASSERT(vp != NULL && vp->v_usecount >= 0,
1689 	    ("vrele: null vp or <=0 v_usecount"));
1690 
1691 	lwkt_gettoken(&vlock, vp->v_interlock);
1692 
1693 	if (vp->v_usecount > 1) {
1694 		vp->v_usecount--;
1695 		lwkt_reltoken(&vlock);
1696 		return;
1697 	}
1698 
1699 	if (vp->v_usecount == 1) {
1700 		vp->v_usecount--;
1701 		/*
1702 		 * We must call VOP_INACTIVE with the node locked and the
1703 		 * usecount 0.  If we are doing a vpu, the node is already
1704 		 * locked, but, in the case of vrele, we must explicitly lock
1705 		 * the vnode before calling VOP_INACTIVE.
1706 		 */
1707 
1708 		if (vn_lock(vp, NULL, LK_EXCLUSIVE, td) == 0)
1709 			VOP_INACTIVE(vp, td);
1710 		vmaybefree(vp);
1711 		lwkt_reltoken(&vlock);
1712 	} else {
1713 #ifdef DIAGNOSTIC
1714 		vprint("vrele: negative ref count", vp);
1715 #endif
1716 		lwkt_reltoken(&vlock);
1717 		panic("vrele: negative ref cnt");
1718 	}
1719 }
1720 
1721 void
1722 vput(struct vnode *vp)
1723 {
1724 	struct thread *td = curthread;	/* XXX */
1725 	lwkt_tokref vlock;
1726 
1727 	KASSERT(vp != NULL, ("vput: null vp"));
1728 
1729 	lwkt_gettoken(&vlock, vp->v_interlock);
1730 
1731 	if (vp->v_usecount > 1) {
1732 		vp->v_usecount--;
1733 		VOP_UNLOCK(vp, &vlock, LK_INTERLOCK, td);
1734 		return;
1735 	}
1736 
1737 	if (vp->v_usecount == 1) {
1738 		vp->v_usecount--;
1739 		/*
1740 		 * We must call VOP_INACTIVE with the node locked.
1741 		 * If we are doing a vpu, the node is already locked,
1742 		 * so we just need to release the vnode mutex.
1743 		 */
1744 		VOP_INACTIVE(vp, td);
1745 		vmaybefree(vp);
1746 		lwkt_reltoken(&vlock);
1747 	} else {
1748 #ifdef DIAGNOSTIC
1749 		vprint("vput: negative ref count", vp);
1750 #endif
1751 		lwkt_reltoken(&vlock);
1752 		panic("vput: negative ref cnt");
1753 	}
1754 }
1755 
1756 /*
1757  * Somebody doesn't want the vnode recycled. ZZZ vnode interlock should
1758  * be held but isn't.
1759  */
1760 void
1761 vhold(struct vnode *vp)
1762 {
1763 	int s;
1764 
1765   	s = splbio();
1766 	vp->v_holdcnt++;
1767 	if (VSHOULDBUSY(vp))
1768 		vbusy(vp);	/* interlock must be held on call */
1769 	splx(s);
1770 }
1771 
1772 /*
1773  * One less who cares about this vnode.
1774  */
1775 void
1776 vdrop(struct vnode *vp)
1777 {
1778 	lwkt_tokref vlock;
1779 
1780 	lwkt_gettoken(&vlock, vp->v_interlock);
1781 	if (vp->v_holdcnt <= 0)
1782 		panic("vdrop: holdcnt");
1783 	vp->v_holdcnt--;
1784 	vmaybefree(vp);
1785 	lwkt_reltoken(&vlock);
1786 }
1787 
1788 int
1789 vmntvnodescan(
1790     struct mount *mp,
1791     int (*fastfunc)(struct mount *mp, struct vnode *vp, void *data),
1792     int (*slowfunc)(struct mount *mp, struct vnode *vp,
1793 		    lwkt_tokref_t vlock, void *data),
1794     void *data
1795 ) {
1796 	lwkt_tokref ilock;
1797 	lwkt_tokref vlock;
1798 	struct vnode *pvp;
1799 	struct vnode *vp;
1800 	int r = 0;
1801 
1802 	/*
1803 	 * Scan the vnodes on the mount's vnode list.  Use a placemarker
1804 	 */
1805 	pvp = zalloc(vnode_zone);
1806 	pvp->v_flag |= VPLACEMARKER;
1807 
1808 	lwkt_gettoken(&ilock, &mntvnode_token);
1809 	TAILQ_INSERT_HEAD(&mp->mnt_nvnodelist, pvp, v_nmntvnodes);
1810 
1811 	while ((vp = TAILQ_NEXT(pvp, v_nmntvnodes)) != NULL) {
1812 		/*
1813 		 * Move the placemarker and skip other placemarkers we
1814 		 * encounter.  The nothing can get in our way so the
1815 		 * mount point on the vp must be valid.
1816 		 */
1817 		TAILQ_REMOVE(&mp->mnt_nvnodelist, pvp, v_nmntvnodes);
1818 		TAILQ_INSERT_AFTER(&mp->mnt_nvnodelist, vp, pvp, v_nmntvnodes);
1819 		if (vp->v_flag & VPLACEMARKER)
1820 			continue;
1821 		KKASSERT(vp->v_mount == mp);
1822 
1823 		/*
1824 		 * Quick test
1825 		 */
1826 		if (fastfunc) {
1827 			if ((r = fastfunc(mp, vp, data)) < 0)
1828 				continue;
1829 			if (r)
1830 				break;
1831 		}
1832 
1833 		/*
1834 		 * Get the vnodes interlock and make sure it is still on the
1835 		 * mount list.  Skip it if it has moved (we may encounter it
1836 		 * later).  Then do the with-interlock test.  The callback
1837 		 * is responsible for releasing the vnode interlock.
1838 		 *
1839 		 * The interlock is type-stable.
1840 		 */
1841 		if (slowfunc) {
1842 			lwkt_gettoken(&vlock, vp->v_interlock);
1843 			if (vp != TAILQ_PREV(pvp, vnodelst, v_nmntvnodes)) {
1844 				printf("vmntvnodescan (debug info only): f=%p vp=%p vnode ripped out from under us\n", slowfunc, vp);
1845 				lwkt_reltoken(&vlock);
1846 				continue;
1847 			}
1848 			if ((r = slowfunc(mp, vp, &vlock, data)) != 0) {
1849 				KKASSERT(lwkt_havetokref(&vlock) == 0);
1850 				break;
1851 			}
1852 			KKASSERT(lwkt_havetokref(&vlock) == 0);
1853 		}
1854 	}
1855 	TAILQ_REMOVE(&mp->mnt_nvnodelist, pvp, v_nmntvnodes);
1856 	zfree(vnode_zone, pvp);
1857 	lwkt_reltoken(&ilock);
1858 	return(r);
1859 }
1860 
1861 /*
1862  * Remove any vnodes in the vnode table belonging to mount point mp.
1863  *
1864  * If FORCECLOSE is not specified, there should not be any active ones,
1865  * return error if any are found (nb: this is a user error, not a
1866  * system error). If FORCECLOSE is specified, detach any active vnodes
1867  * that are found.
1868  *
1869  * If WRITECLOSE is set, only flush out regular file vnodes open for
1870  * writing.
1871  *
1872  * SKIPSYSTEM causes any vnodes marked VSYSTEM to be skipped.
1873  *
1874  * `rootrefs' specifies the base reference count for the root vnode
1875  * of this filesystem. The root vnode is considered busy if its
1876  * v_usecount exceeds this value. On a successful return, vflush()
1877  * will call vrele() on the root vnode exactly rootrefs times.
1878  * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must
1879  * be zero.
1880  */
1881 #ifdef DIAGNOSTIC
1882 static int busyprt = 0;		/* print out busy vnodes */
1883 SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, "");
1884 #endif
1885 
1886 static int vflush_scan(struct mount *mp, struct vnode *vp,
1887 			lwkt_tokref_t vlock, void *data);
1888 
1889 struct vflush_info {
1890 	int flags;
1891 	int busy;
1892 	thread_t td;
1893 };
1894 
1895 int
1896 vflush(struct mount *mp, int rootrefs, int flags)
1897 {
1898 	struct thread *td = curthread;	/* XXX */
1899 	struct vnode *rootvp = NULL;
1900 	int error;
1901 	lwkt_tokref vlock;
1902 	struct vflush_info vflush_info;
1903 
1904 	if (rootrefs > 0) {
1905 		KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0,
1906 		    ("vflush: bad args"));
1907 		/*
1908 		 * Get the filesystem root vnode. We can vput() it
1909 		 * immediately, since with rootrefs > 0, it won't go away.
1910 		 */
1911 		if ((error = VFS_ROOT(mp, &rootvp)) != 0)
1912 			return (error);
1913 		vput(rootvp);
1914 	}
1915 
1916 	vflush_info.busy = 0;
1917 	vflush_info.flags = flags;
1918 	vflush_info.td = td;
1919 	vmntvnodescan(mp, NULL, vflush_scan, &vflush_info);
1920 
1921 	if (rootrefs > 0 && (flags & FORCECLOSE) == 0) {
1922 		/*
1923 		 * If just the root vnode is busy, and if its refcount
1924 		 * is equal to `rootrefs', then go ahead and kill it.
1925 		 */
1926 		lwkt_gettoken(&vlock, rootvp->v_interlock);
1927 		KASSERT(vflush_info.busy > 0, ("vflush: not busy"));
1928 		KASSERT(rootvp->v_usecount >= rootrefs, ("vflush: rootrefs"));
1929 		if (vflush_info.busy == 1 && rootvp->v_usecount == rootrefs) {
1930 			vgonel(rootvp, &vlock, td);
1931 			vflush_info.busy = 0;
1932 		} else {
1933 			lwkt_reltoken(&vlock);
1934 		}
1935 	}
1936 	if (vflush_info.busy)
1937 		return (EBUSY);
1938 	for (; rootrefs > 0; rootrefs--)
1939 		vrele(rootvp);
1940 	return (0);
1941 }
1942 
1943 /*
1944  * The scan callback is made with an interlocked vnode.
1945  */
1946 static int
1947 vflush_scan(struct mount *mp, struct vnode *vp,
1948 	    lwkt_tokref_t vlock, void *data)
1949 {
1950 	struct vflush_info *info = data;
1951 	struct vattr vattr;
1952 
1953 	/*
1954 	 * Skip over a vnodes marked VSYSTEM.
1955 	 */
1956 	if ((info->flags & SKIPSYSTEM) && (vp->v_flag & VSYSTEM)) {
1957 		lwkt_reltoken(vlock);
1958 		return(0);
1959 	}
1960 
1961 	/*
1962 	 * If WRITECLOSE is set, flush out unlinked but still open
1963 	 * files (even if open only for reading) and regular file
1964 	 * vnodes open for writing.
1965 	 */
1966 	if ((info->flags & WRITECLOSE) &&
1967 	    (vp->v_type == VNON ||
1968 	    (VOP_GETATTR(vp, &vattr, info->td) == 0 &&
1969 	    vattr.va_nlink > 0)) &&
1970 	    (vp->v_writecount == 0 || vp->v_type != VREG)) {
1971 		lwkt_reltoken(vlock);
1972 		return(0);
1973 	}
1974 
1975 	/*
1976 	 * With v_usecount == 0, all we need to do is clear out the
1977 	 * vnode data structures and we are done.
1978 	 */
1979 	if (vp->v_usecount == 0) {
1980 		vgonel(vp, vlock, info->td);
1981 		return(0);
1982 	}
1983 
1984 	/*
1985 	 * If FORCECLOSE is set, forcibly close the vnode. For block
1986 	 * or character devices, revert to an anonymous device. For
1987 	 * all other files, just kill them.
1988 	 */
1989 	if (info->flags & FORCECLOSE) {
1990 		if (vp->v_type != VBLK && vp->v_type != VCHR) {
1991 			vgonel(vp, vlock, info->td);
1992 		} else {
1993 			vclean(vp, vlock, 0, info->td);
1994 			vp->v_ops = spec_vnode_vops;
1995 			insmntque(vp, (struct mount *) 0);
1996 		}
1997 		return(0);
1998 	}
1999 #ifdef DIAGNOSTIC
2000 	if (busyprt)
2001 		vprint("vflush: busy vnode", vp);
2002 #endif
2003 	lwkt_reltoken(vlock);
2004 	++info->busy;
2005 	return(0);
2006 }
2007 
2008 /*
2009  * Disassociate the underlying file system from a vnode.
2010  */
2011 static void
2012 vclean(struct vnode *vp, lwkt_tokref_t vlock, int flags, struct thread *td)
2013 {
2014 	int active;
2015 
2016 	/*
2017 	 * Check to see if the vnode is in use. If so we have to reference it
2018 	 * before we clean it out so that its count cannot fall to zero and
2019 	 * generate a race against ourselves to recycle it.
2020 	 */
2021 	if ((active = vp->v_usecount))
2022 		vp->v_usecount++;
2023 
2024 	/*
2025 	 * Prevent the vnode from being recycled or brought into use while we
2026 	 * clean it out.
2027 	 */
2028 	if (vp->v_flag & VXLOCK)
2029 		panic("vclean: deadlock");
2030 	vp->v_flag |= VXLOCK;
2031 	vp->v_vxthread = curthread;
2032 
2033 	/*
2034 	 * Even if the count is zero, the VOP_INACTIVE routine may still
2035 	 * have the object locked while it cleans it out. The VOP_LOCK
2036 	 * ensures that the VOP_INACTIVE routine is done with its work.
2037 	 * For active vnodes, it ensures that no other activity can
2038 	 * occur while the underlying object is being cleaned out.
2039 	 *
2040 	 * NOTE: we continue to hold the vnode interlock through to the
2041 	 * end of vclean().
2042 	 */
2043 	VOP_LOCK(vp, NULL, LK_DRAIN, td);
2044 
2045 	/*
2046 	 * Clean out any buffers associated with the vnode.
2047 	 */
2048 	vinvalbuf(vp, V_SAVE, td, 0, 0);
2049 	VOP_DESTROYVOBJECT(vp);
2050 
2051 	/*
2052 	 * If purging an active vnode, it must be closed and
2053 	 * deactivated before being reclaimed. Note that the
2054 	 * VOP_INACTIVE will unlock the vnode.
2055 	 */
2056 	if (active) {
2057 		if (flags & DOCLOSE)
2058 			VOP_CLOSE(vp, FNONBLOCK, td);
2059 		VOP_INACTIVE(vp, td);
2060 	} else {
2061 		/*
2062 		 * Any other processes trying to obtain this lock must first
2063 		 * wait for VXLOCK to clear, then call the new lock operation.
2064 		 */
2065 		VOP_UNLOCK(vp, NULL, 0, td);
2066 	}
2067 	/*
2068 	 * Reclaim the vnode.
2069 	 */
2070 	if (VOP_RECLAIM(vp, td))
2071 		panic("vclean: cannot reclaim");
2072 
2073 	if (active) {
2074 		/*
2075 		 * Inline copy of vrele() since VOP_INACTIVE
2076 		 * has already been called.
2077 		 */
2078 		if (--vp->v_usecount <= 0) {
2079 #ifdef DIAGNOSTIC
2080 			if (vp->v_usecount < 0 || vp->v_writecount != 0) {
2081 				vprint("vclean: bad ref count", vp);
2082 				panic("vclean: ref cnt");
2083 			}
2084 #endif
2085 			vfree(vp);
2086 		}
2087 	}
2088 
2089 	cache_purge(vp);
2090 	vp->v_vnlock = NULL;
2091 	vmaybefree(vp);
2092 
2093 	/*
2094 	 * Done with purge, notify sleepers of the grim news.
2095 	 */
2096 	vp->v_ops = dead_vnode_vops;
2097 	vn_pollgone(vp);
2098 	vp->v_tag = VT_NON;
2099 	vp->v_flag &= ~VXLOCK;
2100 	vp->v_vxthread = NULL;
2101 	if (vp->v_flag & VXWANT) {
2102 		vp->v_flag &= ~VXWANT;
2103 		wakeup((caddr_t) vp);
2104 	}
2105 	lwkt_reltoken(vlock);
2106 }
2107 
2108 /*
2109  * Eliminate all activity associated with the requested vnode
2110  * and with all vnodes aliased to the requested vnode.
2111  *
2112  * revoke { struct vnode *a_vp, int a_flags }
2113  */
2114 int
2115 vop_stdrevoke(struct vop_revoke_args *ap)
2116 {
2117 	struct vnode *vp, *vq;
2118 	lwkt_tokref ilock;
2119 	dev_t dev;
2120 
2121 	KASSERT((ap->a_flags & REVOKEALL) != 0, ("vop_revoke"));
2122 
2123 	vp = ap->a_vp;
2124 	/*
2125 	 * If a vgone (or vclean) is already in progress,
2126 	 * wait until it is done and return.
2127 	 */
2128 	if (vp->v_flag & VXLOCK) {
2129 		vp->v_flag |= VXWANT;
2130 		/*lwkt_reltoken(vlock); ZZZ */
2131 		tsleep((caddr_t)vp, 0, "vop_revokeall", 0);
2132 		return (0);
2133 	}
2134 
2135 	/*
2136 	 * If the vnode has a device association, scrap all vnodes associated
2137 	 * with the device.  Don't let the device disappear on us while we
2138 	 * are scrapping the vnodes.
2139 	 */
2140 	if (vp->v_type != VCHR && vp->v_type != VBLK)
2141 		return(0);
2142 	if ((dev = vp->v_rdev) == NULL) {
2143 		if ((dev = udev2dev(vp->v_udev, vp->v_type == VBLK)) == NODEV)
2144 			return(0);
2145 	}
2146 	reference_dev(dev);
2147 	for (;;) {
2148 		lwkt_gettoken(&ilock, &spechash_token);
2149 		vq = SLIST_FIRST(&dev->si_hlist);
2150 		lwkt_reltoken(&ilock);
2151 		if (vq == NULL)
2152 			break;
2153 		vgone(vq);
2154 	}
2155 	release_dev(dev);
2156 	return (0);
2157 }
2158 
2159 /*
2160  * Recycle an unused vnode to the front of the free list.
2161  * Release the passed interlock if the vnode will be recycled.
2162  */
2163 int
2164 vrecycle(struct vnode *vp, lwkt_tokref_t inter_lkp, struct thread *td)
2165 {
2166 	lwkt_tokref vlock;
2167 
2168 	lwkt_gettoken(&vlock, vp->v_interlock);
2169 	if (vp->v_usecount == 0) {
2170 		if (inter_lkp)
2171 			lwkt_reltoken(inter_lkp);
2172 		vgonel(vp, &vlock, td);
2173 		return (1);
2174 	}
2175 	lwkt_reltoken(&vlock);
2176 	return (0);
2177 }
2178 
2179 /*
2180  * Eliminate all activity associated with a vnode
2181  * in preparation for reuse.
2182  */
2183 void
2184 vgone(struct vnode *vp)
2185 {
2186 	struct thread *td = curthread;	/* XXX */
2187 	lwkt_tokref vlock;
2188 
2189 	lwkt_gettoken(&vlock, vp->v_interlock);
2190 	vgonel(vp, &vlock, td);
2191 }
2192 
2193 /*
2194  * vgone, with the vp interlock held.
2195  */
2196 void
2197 vgonel(struct vnode *vp, lwkt_tokref_t vlock, struct thread *td)
2198 {
2199 	lwkt_tokref ilock;
2200 	int s;
2201 
2202 	/*
2203 	 * If a vgone (or vclean) is already in progress,
2204 	 * wait until it is done and return.
2205 	 */
2206 	if (vp->v_flag & VXLOCK) {
2207 		vp->v_flag |= VXWANT;
2208 		lwkt_reltoken(vlock);
2209 		tsleep((caddr_t)vp, 0, "vgone", 0);
2210 		return;
2211 	}
2212 
2213 	/*
2214 	 * Clean out the filesystem specific data.
2215 	 */
2216 	vclean(vp, vlock, DOCLOSE, td);
2217 	lwkt_gettokref(vlock);
2218 
2219 	/*
2220 	 * Delete from old mount point vnode list, if on one.
2221 	 */
2222 	if (vp->v_mount != NULL)
2223 		insmntque(vp, (struct mount *)0);
2224 
2225 	/*
2226 	 * If special device, remove it from special device alias list
2227 	 * if it is on one.  This should normally only occur if a vnode is
2228 	 * being revoked as the device should otherwise have been released
2229 	 * naturally.
2230 	 */
2231 	if ((vp->v_type == VBLK || vp->v_type == VCHR) && vp->v_rdev != NULL) {
2232 		v_release_rdev(vp);
2233 	}
2234 
2235 	/*
2236 	 * If it is on the freelist and not already at the head,
2237 	 * move it to the head of the list. The test of the
2238 	 * VDOOMED flag and the reference count of zero is because
2239 	 * it will be removed from the free list by getnewvnode,
2240 	 * but will not have its reference count incremented until
2241 	 * after calling vgone. If the reference count were
2242 	 * incremented first, vgone would (incorrectly) try to
2243 	 * close the previous instance of the underlying object.
2244 	 */
2245 	if (vp->v_usecount == 0 && !(vp->v_flag & VDOOMED)) {
2246 		s = splbio();
2247 		lwkt_gettoken(&ilock, &vnode_free_list_token);
2248 		if (vp->v_flag & VFREE)
2249 			TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
2250 		else
2251 			freevnodes++;
2252 		vp->v_flag |= VFREE;
2253 		TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
2254 		lwkt_reltoken(&ilock);
2255 		splx(s);
2256 	}
2257 	vp->v_type = VBAD;
2258 	lwkt_reltoken(vlock);
2259 }
2260 
2261 /*
2262  * Lookup a vnode by device number.
2263  */
2264 int
2265 vfinddev(dev_t dev, enum vtype type, struct vnode **vpp)
2266 {
2267 	lwkt_tokref ilock;
2268 	struct vnode *vp;
2269 
2270 	lwkt_gettoken(&ilock, &spechash_token);
2271 	SLIST_FOREACH(vp, &dev->si_hlist, v_specnext) {
2272 		if (type == vp->v_type) {
2273 			*vpp = vp;
2274 			lwkt_reltoken(&ilock);
2275 			return (1);
2276 		}
2277 	}
2278 	lwkt_reltoken(&ilock);
2279 	return (0);
2280 }
2281 
2282 /*
2283  * Calculate the total number of references to a special device.  This
2284  * routine may only be called for VBLK and VCHR vnodes since v_rdev is
2285  * an overloaded field.  Since udev2dev can now return NODEV, we have
2286  * to check for a NULL v_rdev.
2287  */
2288 int
2289 count_dev(dev_t dev)
2290 {
2291 	lwkt_tokref ilock;
2292 	struct vnode *vp;
2293 	int count = 0;
2294 
2295 	if (SLIST_FIRST(&dev->si_hlist)) {
2296 		lwkt_gettoken(&ilock, &spechash_token);
2297 		SLIST_FOREACH(vp, &dev->si_hlist, v_specnext) {
2298 			count += vp->v_usecount;
2299 		}
2300 		lwkt_reltoken(&ilock);
2301 	}
2302 	return(count);
2303 }
2304 
2305 int
2306 count_udev(udev_t udev)
2307 {
2308 	dev_t dev;
2309 
2310 	if ((dev = udev2dev(udev, 0)) == NODEV)
2311 		return(0);
2312 	return(count_dev(dev));
2313 }
2314 
2315 int
2316 vcount(struct vnode *vp)
2317 {
2318 	if (vp->v_rdev == NULL)
2319 		return(0);
2320 	return(count_dev(vp->v_rdev));
2321 }
2322 
2323 /*
2324  * Print out a description of a vnode.
2325  */
2326 static char *typename[] =
2327 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD"};
2328 
2329 void
2330 vprint(char *label, struct vnode *vp)
2331 {
2332 	char buf[96];
2333 
2334 	if (label != NULL)
2335 		printf("%s: %p: ", label, (void *)vp);
2336 	else
2337 		printf("%p: ", (void *)vp);
2338 	printf("type %s, usecount %d, writecount %d, refcount %d,",
2339 	    typename[vp->v_type], vp->v_usecount, vp->v_writecount,
2340 	    vp->v_holdcnt);
2341 	buf[0] = '\0';
2342 	if (vp->v_flag & VROOT)
2343 		strcat(buf, "|VROOT");
2344 	if (vp->v_flag & VTEXT)
2345 		strcat(buf, "|VTEXT");
2346 	if (vp->v_flag & VSYSTEM)
2347 		strcat(buf, "|VSYSTEM");
2348 	if (vp->v_flag & VXLOCK)
2349 		strcat(buf, "|VXLOCK");
2350 	if (vp->v_flag & VXWANT)
2351 		strcat(buf, "|VXWANT");
2352 	if (vp->v_flag & VBWAIT)
2353 		strcat(buf, "|VBWAIT");
2354 	if (vp->v_flag & VDOOMED)
2355 		strcat(buf, "|VDOOMED");
2356 	if (vp->v_flag & VFREE)
2357 		strcat(buf, "|VFREE");
2358 	if (vp->v_flag & VOBJBUF)
2359 		strcat(buf, "|VOBJBUF");
2360 	if (buf[0] != '\0')
2361 		printf(" flags (%s)", &buf[1]);
2362 	if (vp->v_data == NULL) {
2363 		printf("\n");
2364 	} else {
2365 		printf("\n\t");
2366 		VOP_PRINT(vp);
2367 	}
2368 }
2369 
2370 #ifdef DDB
2371 #include <ddb/ddb.h>
2372 /*
2373  * List all of the locked vnodes in the system.
2374  * Called when debugging the kernel.
2375  */
2376 DB_SHOW_COMMAND(lockedvnodes, lockedvnodes)
2377 {
2378 	struct thread *td = curthread;	/* XXX */
2379 	lwkt_tokref ilock;
2380 	struct mount *mp, *nmp;
2381 	struct vnode *vp;
2382 
2383 	printf("Locked vnodes\n");
2384 	lwkt_gettoken(&ilock, &mountlist_token);
2385 	for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
2386 		if (vfs_busy(mp, LK_NOWAIT, &ilock, td)) {
2387 			nmp = TAILQ_NEXT(mp, mnt_list);
2388 			continue;
2389 		}
2390 		TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
2391 			if (VOP_ISLOCKED(vp, NULL))
2392 				vprint((char *)0, vp);
2393 		}
2394 		lwkt_gettokref(&ilock);
2395 		nmp = TAILQ_NEXT(mp, mnt_list);
2396 		vfs_unbusy(mp, td);
2397 	}
2398 	lwkt_reltoken(&ilock);
2399 }
2400 #endif
2401 
2402 /*
2403  * Top level filesystem related information gathering.
2404  */
2405 static int	sysctl_ovfs_conf (SYSCTL_HANDLER_ARGS);
2406 
2407 static int
2408 vfs_sysctl(SYSCTL_HANDLER_ARGS)
2409 {
2410 	int *name = (int *)arg1 - 1;	/* XXX */
2411 	u_int namelen = arg2 + 1;	/* XXX */
2412 	struct vfsconf *vfsp;
2413 
2414 #if 1 || defined(COMPAT_PRELITE2)
2415 	/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
2416 	if (namelen == 1)
2417 		return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
2418 #endif
2419 
2420 #ifdef notyet
2421 	/* all sysctl names at this level are at least name and field */
2422 	if (namelen < 2)
2423 		return (ENOTDIR);		/* overloaded */
2424 	if (name[0] != VFS_GENERIC) {
2425 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
2426 			if (vfsp->vfc_typenum == name[0])
2427 				break;
2428 		if (vfsp == NULL)
2429 			return (EOPNOTSUPP);
2430 		return ((*vfsp->vfc_vfsops->vfs_sysctl)(&name[1], namelen - 1,
2431 		    oldp, oldlenp, newp, newlen, p));
2432 	}
2433 #endif
2434 	switch (name[1]) {
2435 	case VFS_MAXTYPENUM:
2436 		if (namelen != 2)
2437 			return (ENOTDIR);
2438 		return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
2439 	case VFS_CONF:
2440 		if (namelen != 3)
2441 			return (ENOTDIR);	/* overloaded */
2442 		for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next)
2443 			if (vfsp->vfc_typenum == name[2])
2444 				break;
2445 		if (vfsp == NULL)
2446 			return (EOPNOTSUPP);
2447 		return (SYSCTL_OUT(req, vfsp, sizeof *vfsp));
2448 	}
2449 	return (EOPNOTSUPP);
2450 }
2451 
2452 SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD, vfs_sysctl,
2453 	"Generic filesystem");
2454 
2455 #if 1 || defined(COMPAT_PRELITE2)
2456 
2457 static int
2458 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
2459 {
2460 	int error;
2461 	struct vfsconf *vfsp;
2462 	struct ovfsconf ovfs;
2463 
2464 	for (vfsp = vfsconf; vfsp; vfsp = vfsp->vfc_next) {
2465 		ovfs.vfc_vfsops = vfsp->vfc_vfsops;	/* XXX used as flag */
2466 		strcpy(ovfs.vfc_name, vfsp->vfc_name);
2467 		ovfs.vfc_index = vfsp->vfc_typenum;
2468 		ovfs.vfc_refcount = vfsp->vfc_refcount;
2469 		ovfs.vfc_flags = vfsp->vfc_flags;
2470 		error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
2471 		if (error)
2472 			return error;
2473 	}
2474 	return 0;
2475 }
2476 
2477 #endif /* 1 || COMPAT_PRELITE2 */
2478 
2479 #if 0
2480 #define KINFO_VNODESLOP	10
2481 /*
2482  * Dump vnode list (via sysctl).
2483  * Copyout address of vnode followed by vnode.
2484  */
2485 /* ARGSUSED */
2486 static int
2487 sysctl_vnode(SYSCTL_HANDLER_ARGS)
2488 {
2489 	struct proc *p = curproc;	/* XXX */
2490 	struct mount *mp, *nmp;
2491 	struct vnode *nvp, *vp;
2492 	lwkt_tokref ilock;
2493 	lwkt_tokref jlock;
2494 	int error;
2495 
2496 #define VPTRSZ	sizeof (struct vnode *)
2497 #define VNODESZ	sizeof (struct vnode)
2498 
2499 	req->lock = 0;
2500 	if (!req->oldptr) /* Make an estimate */
2501 		return (SYSCTL_OUT(req, 0,
2502 			(numvnodes + KINFO_VNODESLOP) * (VPTRSZ + VNODESZ)));
2503 
2504 	lwkt_gettoken(&ilock, &mountlist_token);
2505 	for (mp = TAILQ_FIRST(&mountlist); mp != NULL; mp = nmp) {
2506 		if (vfs_busy(mp, LK_NOWAIT, &ilock, p)) {
2507 			nmp = TAILQ_NEXT(mp, mnt_list);
2508 			continue;
2509 		}
2510 		lwkt_gettoken(&jlock, &mntvnode_token);
2511 again:
2512 		for (vp = TAILQ_FIRST(&mp->mnt_nvnodelist);
2513 		     vp != NULL;
2514 		     vp = nvp) {
2515 			/*
2516 			 * Check that the vp is still associated with
2517 			 * this filesystem.  RACE: could have been
2518 			 * recycled onto the same filesystem.
2519 			 */
2520 			if (vp->v_mount != mp)
2521 				goto again;
2522 			nvp = TAILQ_NEXT(vp, v_nmntvnodes);
2523 			if ((error = SYSCTL_OUT(req, &vp, VPTRSZ)) ||
2524 			    (error = SYSCTL_OUT(req, vp, VNODESZ))) {
2525 				lwkt_reltoken(&jlock);
2526 				return (error);
2527 			}
2528 		}
2529 		lwkt_reltoken(&jlock);
2530 		lwkt_gettokref(&ilock);
2531 		nmp = TAILQ_NEXT(mp, mnt_list);	/* ZZZ */
2532 		vfs_unbusy(mp, p);
2533 	}
2534 	lwkt_reltoken(&ilock);
2535 
2536 	return (0);
2537 }
2538 #endif
2539 
2540 /*
2541  * XXX
2542  * Exporting the vnode list on large systems causes them to crash.
2543  * Exporting the vnode list on medium systems causes sysctl to coredump.
2544  */
2545 #if 0
2546 SYSCTL_PROC(_kern, KERN_VNODE, vnode, CTLTYPE_OPAQUE|CTLFLAG_RD,
2547 	0, 0, sysctl_vnode, "S,vnode", "");
2548 #endif
2549 
2550 /*
2551  * Check to see if a filesystem is mounted on a block device.
2552  */
2553 int
2554 vfs_mountedon(struct vnode *vp)
2555 {
2556 	dev_t dev;
2557 
2558 	if ((dev = vp->v_rdev) == NULL)
2559 		dev = udev2dev(vp->v_udev, (vp->v_type == VBLK));
2560 	if (dev != NODEV && dev->si_mountpoint)
2561 		return (EBUSY);
2562 	return (0);
2563 }
2564 
2565 /*
2566  * Unmount all filesystems. The list is traversed in reverse order
2567  * of mounting to avoid dependencies.
2568  */
2569 void
2570 vfs_unmountall(void)
2571 {
2572 	struct mount *mp;
2573 	struct thread *td = curthread;
2574 	int error;
2575 
2576 	if (td->td_proc == NULL)
2577 		td = initproc->p_thread;	/* XXX XXX use proc0 instead? */
2578 
2579 	/*
2580 	 * Since this only runs when rebooting, it is not interlocked.
2581 	 */
2582 	while(!TAILQ_EMPTY(&mountlist)) {
2583 		mp = TAILQ_LAST(&mountlist, mntlist);
2584 		error = dounmount(mp, MNT_FORCE, td);
2585 		if (error) {
2586 			TAILQ_REMOVE(&mountlist, mp, mnt_list);
2587 			printf("unmount of %s failed (",
2588 			    mp->mnt_stat.f_mntonname);
2589 			if (error == EBUSY)
2590 				printf("BUSY)\n");
2591 			else
2592 				printf("%d)\n", error);
2593 		} else {
2594 			/* The unmount has removed mp from the mountlist */
2595 		}
2596 	}
2597 }
2598 
2599 /*
2600  * Build hash lists of net addresses and hang them off the mount point.
2601  * Called by ufs_mount() to set up the lists of export addresses.
2602  */
2603 static int
2604 vfs_hang_addrlist(struct mount *mp, struct netexport *nep,
2605 		struct export_args *argp)
2606 {
2607 	struct netcred *np;
2608 	struct radix_node_head *rnh;
2609 	int i;
2610 	struct radix_node *rn;
2611 	struct sockaddr *saddr, *smask = 0;
2612 	struct domain *dom;
2613 	int error;
2614 
2615 	if (argp->ex_addrlen == 0) {
2616 		if (mp->mnt_flag & MNT_DEFEXPORTED)
2617 			return (EPERM);
2618 		np = &nep->ne_defexported;
2619 		np->netc_exflags = argp->ex_flags;
2620 		np->netc_anon = argp->ex_anon;
2621 		np->netc_anon.cr_ref = 1;
2622 		mp->mnt_flag |= MNT_DEFEXPORTED;
2623 		return (0);
2624 	}
2625 
2626 	if (argp->ex_addrlen < 0 || argp->ex_addrlen > MLEN)
2627 		return (EINVAL);
2628 	if (argp->ex_masklen < 0 || argp->ex_masklen > MLEN)
2629 		return (EINVAL);
2630 
2631 	i = sizeof(struct netcred) + argp->ex_addrlen + argp->ex_masklen;
2632 	np = (struct netcred *) malloc(i, M_NETADDR, M_WAITOK);
2633 	bzero((caddr_t) np, i);
2634 	saddr = (struct sockaddr *) (np + 1);
2635 	if ((error = copyin(argp->ex_addr, (caddr_t) saddr, argp->ex_addrlen)))
2636 		goto out;
2637 	if (saddr->sa_len > argp->ex_addrlen)
2638 		saddr->sa_len = argp->ex_addrlen;
2639 	if (argp->ex_masklen) {
2640 		smask = (struct sockaddr *)((caddr_t)saddr + argp->ex_addrlen);
2641 		error = copyin(argp->ex_mask, (caddr_t)smask, argp->ex_masklen);
2642 		if (error)
2643 			goto out;
2644 		if (smask->sa_len > argp->ex_masklen)
2645 			smask->sa_len = argp->ex_masklen;
2646 	}
2647 	i = saddr->sa_family;
2648 	if ((rnh = nep->ne_rtable[i]) == 0) {
2649 		/*
2650 		 * Seems silly to initialize every AF when most are not used,
2651 		 * do so on demand here
2652 		 */
2653 		for (dom = domains; dom; dom = dom->dom_next)
2654 			if (dom->dom_family == i && dom->dom_rtattach) {
2655 				dom->dom_rtattach((void **) &nep->ne_rtable[i],
2656 				    dom->dom_rtoffset);
2657 				break;
2658 			}
2659 		if ((rnh = nep->ne_rtable[i]) == 0) {
2660 			error = ENOBUFS;
2661 			goto out;
2662 		}
2663 	}
2664 	rn = (*rnh->rnh_addaddr) ((caddr_t) saddr, (caddr_t) smask, rnh,
2665 	    np->netc_rnodes);
2666 	if (rn == 0 || np != (struct netcred *) rn) {	/* already exists */
2667 		error = EPERM;
2668 		goto out;
2669 	}
2670 	np->netc_exflags = argp->ex_flags;
2671 	np->netc_anon = argp->ex_anon;
2672 	np->netc_anon.cr_ref = 1;
2673 	return (0);
2674 out:
2675 	free(np, M_NETADDR);
2676 	return (error);
2677 }
2678 
2679 /* ARGSUSED */
2680 static int
2681 vfs_free_netcred(struct radix_node *rn, void *w)
2682 {
2683 	struct radix_node_head *rnh = (struct radix_node_head *) w;
2684 
2685 	(*rnh->rnh_deladdr) (rn->rn_key, rn->rn_mask, rnh);
2686 	free((caddr_t) rn, M_NETADDR);
2687 	return (0);
2688 }
2689 
2690 /*
2691  * Free the net address hash lists that are hanging off the mount points.
2692  */
2693 static void
2694 vfs_free_addrlist(struct netexport *nep)
2695 {
2696 	int i;
2697 	struct radix_node_head *rnh;
2698 
2699 	for (i = 0; i <= AF_MAX; i++)
2700 		if ((rnh = nep->ne_rtable[i])) {
2701 			(*rnh->rnh_walktree) (rnh, vfs_free_netcred,
2702 			    (caddr_t) rnh);
2703 			free((caddr_t) rnh, M_RTABLE);
2704 			nep->ne_rtable[i] = 0;
2705 		}
2706 }
2707 
2708 int
2709 vfs_export(struct mount *mp, struct netexport *nep, struct export_args *argp)
2710 {
2711 	int error;
2712 
2713 	if (argp->ex_flags & MNT_DELEXPORT) {
2714 		if (mp->mnt_flag & MNT_EXPUBLIC) {
2715 			vfs_setpublicfs(NULL, NULL, NULL);
2716 			mp->mnt_flag &= ~MNT_EXPUBLIC;
2717 		}
2718 		vfs_free_addrlist(nep);
2719 		mp->mnt_flag &= ~(MNT_EXPORTED | MNT_DEFEXPORTED);
2720 	}
2721 	if (argp->ex_flags & MNT_EXPORTED) {
2722 		if (argp->ex_flags & MNT_EXPUBLIC) {
2723 			if ((error = vfs_setpublicfs(mp, nep, argp)) != 0)
2724 				return (error);
2725 			mp->mnt_flag |= MNT_EXPUBLIC;
2726 		}
2727 		if ((error = vfs_hang_addrlist(mp, nep, argp)))
2728 			return (error);
2729 		mp->mnt_flag |= MNT_EXPORTED;
2730 	}
2731 	return (0);
2732 }
2733 
2734 
2735 /*
2736  * Set the publicly exported filesystem (WebNFS). Currently, only
2737  * one public filesystem is possible in the spec (RFC 2054 and 2055)
2738  */
2739 int
2740 vfs_setpublicfs(struct mount *mp, struct netexport *nep,
2741 		struct export_args *argp)
2742 {
2743 	int error;
2744 	struct vnode *rvp;
2745 	char *cp;
2746 
2747 	/*
2748 	 * mp == NULL -> invalidate the current info, the FS is
2749 	 * no longer exported. May be called from either vfs_export
2750 	 * or unmount, so check if it hasn't already been done.
2751 	 */
2752 	if (mp == NULL) {
2753 		if (nfs_pub.np_valid) {
2754 			nfs_pub.np_valid = 0;
2755 			if (nfs_pub.np_index != NULL) {
2756 				FREE(nfs_pub.np_index, M_TEMP);
2757 				nfs_pub.np_index = NULL;
2758 			}
2759 		}
2760 		return (0);
2761 	}
2762 
2763 	/*
2764 	 * Only one allowed at a time.
2765 	 */
2766 	if (nfs_pub.np_valid != 0 && mp != nfs_pub.np_mount)
2767 		return (EBUSY);
2768 
2769 	/*
2770 	 * Get real filehandle for root of exported FS.
2771 	 */
2772 	bzero((caddr_t)&nfs_pub.np_handle, sizeof(nfs_pub.np_handle));
2773 	nfs_pub.np_handle.fh_fsid = mp->mnt_stat.f_fsid;
2774 
2775 	if ((error = VFS_ROOT(mp, &rvp)))
2776 		return (error);
2777 
2778 	if ((error = VFS_VPTOFH(rvp, &nfs_pub.np_handle.fh_fid)))
2779 		return (error);
2780 
2781 	vput(rvp);
2782 
2783 	/*
2784 	 * If an indexfile was specified, pull it in.
2785 	 */
2786 	if (argp->ex_indexfile != NULL) {
2787 		MALLOC(nfs_pub.np_index, char *, MAXNAMLEN + 1, M_TEMP,
2788 		    M_WAITOK);
2789 		error = copyinstr(argp->ex_indexfile, nfs_pub.np_index,
2790 		    MAXNAMLEN, (size_t *)0);
2791 		if (!error) {
2792 			/*
2793 			 * Check for illegal filenames.
2794 			 */
2795 			for (cp = nfs_pub.np_index; *cp; cp++) {
2796 				if (*cp == '/') {
2797 					error = EINVAL;
2798 					break;
2799 				}
2800 			}
2801 		}
2802 		if (error) {
2803 			FREE(nfs_pub.np_index, M_TEMP);
2804 			return (error);
2805 		}
2806 	}
2807 
2808 	nfs_pub.np_mount = mp;
2809 	nfs_pub.np_valid = 1;
2810 	return (0);
2811 }
2812 
2813 struct netcred *
2814 vfs_export_lookup(struct mount *mp, struct netexport *nep,
2815 		struct sockaddr *nam)
2816 {
2817 	struct netcred *np;
2818 	struct radix_node_head *rnh;
2819 	struct sockaddr *saddr;
2820 
2821 	np = NULL;
2822 	if (mp->mnt_flag & MNT_EXPORTED) {
2823 		/*
2824 		 * Lookup in the export list first.
2825 		 */
2826 		if (nam != NULL) {
2827 			saddr = nam;
2828 			rnh = nep->ne_rtable[saddr->sa_family];
2829 			if (rnh != NULL) {
2830 				np = (struct netcred *)
2831 					(*rnh->rnh_matchaddr)((caddr_t)saddr,
2832 							      rnh);
2833 				if (np && np->netc_rnodes->rn_flags & RNF_ROOT)
2834 					np = NULL;
2835 			}
2836 		}
2837 		/*
2838 		 * If no address match, use the default if it exists.
2839 		 */
2840 		if (np == NULL && mp->mnt_flag & MNT_DEFEXPORTED)
2841 			np = &nep->ne_defexported;
2842 	}
2843 	return (np);
2844 }
2845 
2846 /*
2847  * perform msync on all vnodes under a mount point.  The mount point must
2848  * be locked.  This code is also responsible for lazy-freeing unreferenced
2849  * vnodes whos VM objects no longer contain pages.
2850  *
2851  * NOTE: MNT_WAIT still skips vnodes in the VXLOCK state.
2852  */
2853 static int vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data);
2854 static int vfs_msync_scan2(struct mount *mp, struct vnode *vp,
2855 			    lwkt_tokref_t vlock, void *data);
2856 
2857 void
2858 vfs_msync(struct mount *mp, int flags)
2859 {
2860 	vmntvnodescan(mp, vfs_msync_scan1, vfs_msync_scan2, (void *)flags);
2861 }
2862 
2863 /*
2864  * scan1 is a fast pre-check.  There could be hundreds of thousands of
2865  * vnodes, we cannot afford to do anything heavy weight until we have a
2866  * fairly good indication that there is work to do.
2867  */
2868 static
2869 int
2870 vfs_msync_scan1(struct mount *mp, struct vnode *vp, void *data)
2871 {
2872 	int flags = (int)data;
2873 
2874 	if ((vp->v_flag & VXLOCK) == 0) {
2875 		if (VSHOULDFREE(vp))
2876 			return(0);
2877 		if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
2878 		    (vp->v_flag & VOBJDIRTY) &&
2879 		    (flags == MNT_WAIT || VOP_ISLOCKED(vp, NULL) == 0)) {
2880 			return(0);
2881 		}
2882 	}
2883 	return(-1);
2884 }
2885 
2886 static
2887 int
2888 vfs_msync_scan2(struct mount *mp, struct vnode *vp,
2889 		lwkt_tokref_t vlock, void *data)
2890 {
2891 	vm_object_t obj;
2892 	int error;
2893 	int flags = (int)data;
2894 
2895 	if (vp->v_flag & VXLOCK)
2896 		return(0);
2897 
2898 	if ((mp->mnt_flag & MNT_RDONLY) == 0 &&
2899 	    (vp->v_flag & VOBJDIRTY) &&
2900 	    (flags == MNT_WAIT || VOP_ISLOCKED(vp, NULL) == 0)) {
2901 		error = vget(vp, vlock, LK_EXCLUSIVE | LK_RETRY | LK_NOOBJ | LK_INTERLOCK, curthread);
2902 		if (error == 0) {
2903 			if (VOP_GETVOBJECT(vp, &obj) == 0) {
2904 				vm_object_page_clean(obj, 0, 0,
2905 				 flags == MNT_WAIT ? OBJPC_SYNC : OBJPC_NOSYNC);
2906 			}
2907 			vput(vp);
2908 		}
2909 		return(0);
2910 	}
2911 	vmaybefree(vp);
2912 	lwkt_reltoken(vlock);
2913 	return(0);
2914 }
2915 
2916 /*
2917  * Create the VM object needed for VMIO and mmap support.  This
2918  * is done for all VREG files in the system.  Some filesystems might
2919  * afford the additional metadata buffering capability of the
2920  * VMIO code by making the device node be VMIO mode also.
2921  *
2922  * vp must be locked when vfs_object_create is called.
2923  */
2924 int
2925 vfs_object_create(struct vnode *vp, struct thread *td)
2926 {
2927 	return (VOP_CREATEVOBJECT(vp, td));
2928 }
2929 
2930 /*
2931  * NOTE: the vnode interlock must be held during the call.  We have to recheck
2932  * the VFREE flag since the vnode may have been removed from the free list
2933  * while we were blocked on vnode_free_list_token.  The use or hold count
2934  * must have already been bumped by the caller.
2935  */
2936 static void
2937 vbusy(struct vnode *vp)
2938 {
2939 	lwkt_tokref ilock;
2940 
2941 	lwkt_gettoken(&ilock, &vnode_free_list_token);
2942 	if ((vp->v_flag & VFREE) != 0) {
2943 	    TAILQ_REMOVE(&vnode_free_list, vp, v_freelist);
2944 	    freevnodes--;
2945 	    vp->v_flag &= ~(VFREE|VAGE);
2946 	}
2947 	lwkt_reltoken(&ilock);
2948 }
2949 
2950 /*
2951  * NOTE: the vnode interlock must be held during the call.  The use or hold
2952  * count must have already been bumped by the caller.  We use a VINFREE to
2953  * interlock against other calls to vfree() which might occur while we
2954  * are blocked.  The vnode cannot be reused until it has actually been
2955  * placed on the free list, so there are no other races even though the
2956  * use and hold counts are 0.
2957  */
2958 static void
2959 vfree(struct vnode *vp)
2960 {
2961 	lwkt_tokref ilock;
2962 
2963 	if ((vp->v_flag & VINFREE) == 0) {
2964 		vp->v_flag |= VINFREE;
2965 		lwkt_gettoken(&ilock, &vnode_free_list_token); /* can block */
2966 		KASSERT((vp->v_flag & VFREE) == 0, ("vnode already free"));
2967 		if (vp->v_flag & VAGE) {
2968 			TAILQ_INSERT_HEAD(&vnode_free_list, vp, v_freelist);
2969 		} else {
2970 			TAILQ_INSERT_TAIL(&vnode_free_list, vp, v_freelist);
2971 		}
2972 		freevnodes++;
2973 		vp->v_flag &= ~(VAGE|VINFREE);
2974 		vp->v_flag |= VFREE;
2975 		lwkt_reltoken(&ilock);	/* can block */
2976 	}
2977 }
2978 
2979 
2980 /*
2981  * Record a process's interest in events which might happen to
2982  * a vnode.  Because poll uses the historic select-style interface
2983  * internally, this routine serves as both the ``check for any
2984  * pending events'' and the ``record my interest in future events''
2985  * functions.  (These are done together, while the lock is held,
2986  * to avoid race conditions.)
2987  */
2988 int
2989 vn_pollrecord(struct vnode *vp, struct thread *td, int events)
2990 {
2991 	lwkt_tokref ilock;
2992 
2993 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
2994 	if (vp->v_pollinfo.vpi_revents & events) {
2995 		/*
2996 		 * This leaves events we are not interested
2997 		 * in available for the other process which
2998 		 * which presumably had requested them
2999 		 * (otherwise they would never have been
3000 		 * recorded).
3001 		 */
3002 		events &= vp->v_pollinfo.vpi_revents;
3003 		vp->v_pollinfo.vpi_revents &= ~events;
3004 
3005 		lwkt_reltoken(&ilock);
3006 		return events;
3007 	}
3008 	vp->v_pollinfo.vpi_events |= events;
3009 	selrecord(td, &vp->v_pollinfo.vpi_selinfo);
3010 	lwkt_reltoken(&ilock);
3011 	return 0;
3012 }
3013 
3014 /*
3015  * Note the occurrence of an event.  If the VN_POLLEVENT macro is used,
3016  * it is possible for us to miss an event due to race conditions, but
3017  * that condition is expected to be rare, so for the moment it is the
3018  * preferred interface.
3019  */
3020 void
3021 vn_pollevent(struct vnode *vp, int events)
3022 {
3023 	lwkt_tokref ilock;
3024 
3025 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
3026 	if (vp->v_pollinfo.vpi_events & events) {
3027 		/*
3028 		 * We clear vpi_events so that we don't
3029 		 * call selwakeup() twice if two events are
3030 		 * posted before the polling process(es) is
3031 		 * awakened.  This also ensures that we take at
3032 		 * most one selwakeup() if the polling process
3033 		 * is no longer interested.  However, it does
3034 		 * mean that only one event can be noticed at
3035 		 * a time.  (Perhaps we should only clear those
3036 		 * event bits which we note?) XXX
3037 		 */
3038 		vp->v_pollinfo.vpi_events = 0;	/* &= ~events ??? */
3039 		vp->v_pollinfo.vpi_revents |= events;
3040 		selwakeup(&vp->v_pollinfo.vpi_selinfo);
3041 	}
3042 	lwkt_reltoken(&ilock);
3043 }
3044 
3045 /*
3046  * Wake up anyone polling on vp because it is being revoked.
3047  * This depends on dead_poll() returning POLLHUP for correct
3048  * behavior.
3049  */
3050 void
3051 vn_pollgone(struct vnode *vp)
3052 {
3053 	lwkt_tokref ilock;
3054 
3055 	lwkt_gettoken(&ilock, &vp->v_pollinfo.vpi_token);
3056 	if (vp->v_pollinfo.vpi_events) {
3057 		vp->v_pollinfo.vpi_events = 0;
3058 		selwakeup(&vp->v_pollinfo.vpi_selinfo);
3059 	}
3060 	lwkt_reltoken(&ilock);
3061 }
3062 
3063 
3064 
3065 /*
3066  * Routine to create and manage a filesystem syncer vnode.
3067  */
3068 #define sync_close ((int (*) (struct  vop_close_args *))nullop)
3069 static int	sync_fsync (struct  vop_fsync_args *);
3070 static int	sync_inactive (struct  vop_inactive_args *);
3071 static int	sync_reclaim  (struct  vop_reclaim_args *);
3072 #define sync_lock ((int (*) (struct  vop_lock_args *))vop_nolock)
3073 #define sync_unlock ((int (*) (struct  vop_unlock_args *))vop_nounlock)
3074 static int	sync_print (struct vop_print_args *);
3075 #define sync_islocked ((int(*) (struct vop_islocked_args *))vop_noislocked)
3076 
3077 static struct vop_ops *sync_vnode_vops;
3078 static struct vnodeopv_entry_desc sync_vnodeop_entries[] = {
3079 	{ &vop_default_desc,	vop_eopnotsupp },
3080 	{ &vop_close_desc,	(void *) sync_close },		/* close */
3081 	{ &vop_fsync_desc,	(void *) sync_fsync },		/* fsync */
3082 	{ &vop_inactive_desc,	(void *) sync_inactive },	/* inactive */
3083 	{ &vop_reclaim_desc,	(void *) sync_reclaim },	/* reclaim */
3084 	{ &vop_lock_desc,	(void *) sync_lock },		/* lock */
3085 	{ &vop_unlock_desc,	(void *) sync_unlock },		/* unlock */
3086 	{ &vop_print_desc,	(void *) sync_print },		/* print */
3087 	{ &vop_islocked_desc,	(void *) sync_islocked },	/* islocked */
3088 	{ NULL, NULL }
3089 };
3090 
3091 static struct vnodeopv_desc sync_vnodeop_opv_desc =
3092 	{ &sync_vnode_vops, sync_vnodeop_entries };
3093 
3094 VNODEOP_SET(sync_vnodeop_opv_desc);
3095 
3096 /*
3097  * Create a new filesystem syncer vnode for the specified mount point.
3098  * This vnode is placed on the worklist and is responsible for sync'ing
3099  * the filesystem.
3100  *
3101  * NOTE: read-only mounts are also placed on the worklist.  The filesystem
3102  * sync code is also responsible for cleaning up vnodes.
3103  */
3104 int
3105 vfs_allocate_syncvnode(struct mount *mp)
3106 {
3107 	struct vnode *vp;
3108 	static long start, incr, next;
3109 	int error;
3110 
3111 	/* Allocate a new vnode */
3112 	if ((error = getnewvnode(VT_VFS, mp, sync_vnode_vops, &vp)) != 0) {
3113 		mp->mnt_syncer = NULL;
3114 		return (error);
3115 	}
3116 	vp->v_type = VNON;
3117 	/*
3118 	 * Place the vnode onto the syncer worklist. We attempt to
3119 	 * scatter them about on the list so that they will go off
3120 	 * at evenly distributed times even if all the filesystems
3121 	 * are mounted at once.
3122 	 */
3123 	next += incr;
3124 	if (next == 0 || next > syncer_maxdelay) {
3125 		start /= 2;
3126 		incr /= 2;
3127 		if (start == 0) {
3128 			start = syncer_maxdelay / 2;
3129 			incr = syncer_maxdelay;
3130 		}
3131 		next = start;
3132 	}
3133 	vn_syncer_add_to_worklist(vp, syncdelay > 0 ? next % syncdelay : 0);
3134 	mp->mnt_syncer = vp;
3135 	return (0);
3136 }
3137 
3138 /*
3139  * Do a lazy sync of the filesystem.
3140  *
3141  * sync_fsync { struct vnode *a_vp, struct ucred *a_cred, int a_waitfor,
3142  *		struct thread *a_td }
3143  */
3144 static int
3145 sync_fsync(struct vop_fsync_args *ap)
3146 {
3147 	struct vnode *syncvp = ap->a_vp;
3148 	struct mount *mp = syncvp->v_mount;
3149 	struct thread *td = ap->a_td;
3150 	lwkt_tokref ilock;
3151 	int asyncflag;
3152 
3153 	/*
3154 	 * We only need to do something if this is a lazy evaluation.
3155 	 */
3156 	if (ap->a_waitfor != MNT_LAZY)
3157 		return (0);
3158 
3159 	/*
3160 	 * Move ourselves to the back of the sync list.
3161 	 */
3162 	vn_syncer_add_to_worklist(syncvp, syncdelay);
3163 
3164 	/*
3165 	 * Walk the list of vnodes pushing all that are dirty and
3166 	 * not already on the sync list, and freeing vnodes which have
3167 	 * no refs and whos VM objects are empty.  vfs_msync() handles
3168 	 * the VM issues and must be called whether the mount is readonly
3169 	 * or not.
3170 	 */
3171 	lwkt_gettoken(&ilock, &mountlist_token);
3172 	if (vfs_busy(mp, LK_EXCLUSIVE | LK_NOWAIT, &ilock, td) != 0) {
3173 		lwkt_reltoken(&ilock);
3174 		return (0);
3175 	}
3176 	if (mp->mnt_flag & MNT_RDONLY) {
3177 		vfs_msync(mp, MNT_NOWAIT);
3178 	} else {
3179 		asyncflag = mp->mnt_flag & MNT_ASYNC;
3180 		mp->mnt_flag &= ~MNT_ASYNC;	/* ZZZ hack */
3181 		vfs_msync(mp, MNT_NOWAIT);
3182 		VFS_SYNC(mp, MNT_LAZY, td);
3183 		if (asyncflag)
3184 			mp->mnt_flag |= MNT_ASYNC;
3185 	}
3186 	vfs_unbusy(mp, td);
3187 	return (0);
3188 }
3189 
3190 /*
3191  * The syncer vnode is no referenced.
3192  *
3193  * sync_inactive { struct vnode *a_vp, struct proc *a_p }
3194  */
3195 static int
3196 sync_inactive(struct vop_inactive_args *ap)
3197 {
3198 	vgone(ap->a_vp);
3199 	return (0);
3200 }
3201 
3202 /*
3203  * The syncer vnode is no longer needed and is being decommissioned.
3204  *
3205  * Modifications to the worklist must be protected at splbio().
3206  *
3207  *	sync_reclaim { struct vnode *a_vp }
3208  */
3209 static int
3210 sync_reclaim(struct vop_reclaim_args *ap)
3211 {
3212 	struct vnode *vp = ap->a_vp;
3213 	int s;
3214 
3215 	s = splbio();
3216 	vp->v_mount->mnt_syncer = NULL;
3217 	if (vp->v_flag & VONWORKLST) {
3218 		LIST_REMOVE(vp, v_synclist);
3219 		vp->v_flag &= ~VONWORKLST;
3220 	}
3221 	splx(s);
3222 
3223 	return (0);
3224 }
3225 
3226 /*
3227  * Print out a syncer vnode.
3228  *
3229  *	sync_print { struct vnode *a_vp }
3230  */
3231 static int
3232 sync_print(struct vop_print_args *ap)
3233 {
3234 	struct vnode *vp = ap->a_vp;
3235 
3236 	printf("syncer vnode");
3237 	if (vp->v_vnlock != NULL)
3238 		lockmgr_printinfo(vp->v_vnlock);
3239 	printf("\n");
3240 	return (0);
3241 }
3242 
3243 /*
3244  * extract the dev_t from a VBLK or VCHR.  The vnode must have been opened
3245  * (or v_rdev might be NULL).
3246  */
3247 dev_t
3248 vn_todev(struct vnode *vp)
3249 {
3250 	if (vp->v_type != VBLK && vp->v_type != VCHR)
3251 		return (NODEV);
3252 	KKASSERT(vp->v_rdev != NULL);
3253 	return (vp->v_rdev);
3254 }
3255 
3256 /*
3257  * Check if vnode represents a disk device.  The vnode does not need to be
3258  * opened.
3259  */
3260 int
3261 vn_isdisk(struct vnode *vp, int *errp)
3262 {
3263 	dev_t dev;
3264 
3265 	if (vp->v_type != VBLK && vp->v_type != VCHR) {
3266 		if (errp != NULL)
3267 			*errp = ENOTBLK;
3268 		return (0);
3269 	}
3270 
3271 	if ((dev = vp->v_rdev) == NULL)
3272 		dev = udev2dev(vp->v_udev, (vp->v_type == VBLK));
3273 	if (dev == NULL || dev == NODEV) {
3274 		if (errp != NULL)
3275 			*errp = ENXIO;
3276 		return (0);
3277 	}
3278 	if (dev_is_good(dev) == 0) {
3279 		if (errp != NULL)
3280 			*errp = ENXIO;
3281 		return (0);
3282 	}
3283 	if ((dev_dflags(dev) & D_DISK) == 0) {
3284 		if (errp != NULL)
3285 			*errp = ENOTBLK;
3286 		return (0);
3287 	}
3288 	if (errp != NULL)
3289 		*errp = 0;
3290 	return (1);
3291 }
3292 
3293 void
3294 NDFREE(struct nameidata *ndp, const uint flags)
3295 {
3296 	if (!(flags & NDF_NO_FREE_PNBUF) &&
3297 	    (ndp->ni_cnd.cn_flags & CNP_HASBUF)) {
3298 		zfree(namei_zone, ndp->ni_cnd.cn_pnbuf);
3299 		ndp->ni_cnd.cn_flags &= ~CNP_HASBUF;
3300 	}
3301 	if (!(flags & NDF_NO_DNCP_RELE) &&
3302 	    (ndp->ni_cnd.cn_flags & CNP_WANTDNCP) &&
3303 	    ndp->ni_dncp) {
3304 		cache_drop(ndp->ni_dncp);
3305 		ndp->ni_dncp = NULL;
3306 	}
3307 	if (!(flags & NDF_NO_NCP_RELE) &&
3308 	    (ndp->ni_cnd.cn_flags & CNP_WANTNCP) &&
3309 	    ndp->ni_ncp) {
3310 		cache_drop(ndp->ni_ncp);
3311 		ndp->ni_ncp = NULL;
3312 	}
3313 	if (!(flags & NDF_NO_DVP_UNLOCK) &&
3314 	    (ndp->ni_cnd.cn_flags & CNP_LOCKPARENT) &&
3315 	    ndp->ni_dvp != ndp->ni_vp) {
3316 		VOP_UNLOCK(ndp->ni_dvp, NULL, 0, ndp->ni_cnd.cn_td);
3317 	}
3318 	if (!(flags & NDF_NO_DVP_RELE) &&
3319 	    (ndp->ni_cnd.cn_flags & (CNP_LOCKPARENT|CNP_WANTPARENT))) {
3320 		vrele(ndp->ni_dvp);
3321 		ndp->ni_dvp = NULL;
3322 	}
3323 	if (!(flags & NDF_NO_VP_UNLOCK) &&
3324 	    (ndp->ni_cnd.cn_flags & CNP_LOCKLEAF) && ndp->ni_vp) {
3325 		VOP_UNLOCK(ndp->ni_vp, NULL, 0, ndp->ni_cnd.cn_td);
3326 	}
3327 	if (!(flags & NDF_NO_VP_RELE) &&
3328 	    ndp->ni_vp) {
3329 		vrele(ndp->ni_vp);
3330 		ndp->ni_vp = NULL;
3331 	}
3332 	if (!(flags & NDF_NO_STARTDIR_RELE) &&
3333 	    (ndp->ni_cnd.cn_flags & CNP_SAVESTART)) {
3334 		vrele(ndp->ni_startdir);
3335 		ndp->ni_startdir = NULL;
3336 	}
3337 }
3338 
3339 #ifdef DEBUG_VFS_LOCKS
3340 
3341 void
3342 assert_vop_locked(struct vnode *vp, const char *str)
3343 {
3344 	if (vp && IS_LOCKING_VFS(vp) && !VOP_ISLOCKED(vp, NULL)) {
3345 		panic("%s: %p is not locked shared but should be", str, vp);
3346 	}
3347 }
3348 
3349 void
3350 assert_vop_unlocked(struct vnode *vp, const char *str)
3351 {
3352 	if (vp && IS_LOCKING_VFS(vp)) {
3353 		if (VOP_ISLOCKED(vp, curthread) == LK_EXCLUSIVE) {
3354 			panic("%s: %p is locked but should not be", str, vp);
3355 		}
3356 	}
3357 }
3358 
3359 #endif
3360