xref: /freebsd/sys/kern/vfs_subr.c (revision 7e5c51e523ae2a0b4f00cf5d6b9168e053d8eed1)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1989, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  * (c) UNIX System Laboratories, Inc.
7  * All or some portions of this file are derived from material licensed
8  * to the University of California by American Telephone and Telegraph
9  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10  * the permission of UNIX System Laboratories, Inc.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  *
36  *	@(#)vfs_subr.c	8.31 (Berkeley) 5/26/95
37  */
38 
39 /*
40  * External virtual filesystem routines
41  */
42 
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
45 
46 #include "opt_ddb.h"
47 #include "opt_watchdog.h"
48 
49 #include <sys/param.h>
50 #include <sys/systm.h>
51 #include <sys/bio.h>
52 #include <sys/buf.h>
53 #include <sys/capsicum.h>
54 #include <sys/condvar.h>
55 #include <sys/conf.h>
56 #include <sys/counter.h>
57 #include <sys/dirent.h>
58 #include <sys/event.h>
59 #include <sys/eventhandler.h>
60 #include <sys/extattr.h>
61 #include <sys/file.h>
62 #include <sys/fcntl.h>
63 #include <sys/jail.h>
64 #include <sys/kdb.h>
65 #include <sys/kernel.h>
66 #include <sys/kthread.h>
67 #include <sys/ktr.h>
68 #include <sys/lockf.h>
69 #include <sys/malloc.h>
70 #include <sys/mount.h>
71 #include <sys/namei.h>
72 #include <sys/pctrie.h>
73 #include <sys/priv.h>
74 #include <sys/reboot.h>
75 #include <sys/refcount.h>
76 #include <sys/rwlock.h>
77 #include <sys/sched.h>
78 #include <sys/sleepqueue.h>
79 #include <sys/smr.h>
80 #include <sys/smp.h>
81 #include <sys/stat.h>
82 #include <sys/sysctl.h>
83 #include <sys/syslog.h>
84 #include <sys/vmmeter.h>
85 #include <sys/vnode.h>
86 #include <sys/watchdog.h>
87 
88 #include <machine/stdarg.h>
89 
90 #include <security/mac/mac_framework.h>
91 
92 #include <vm/vm.h>
93 #include <vm/vm_object.h>
94 #include <vm/vm_extern.h>
95 #include <vm/pmap.h>
96 #include <vm/vm_map.h>
97 #include <vm/vm_page.h>
98 #include <vm/vm_kern.h>
99 #include <vm/uma.h>
100 
101 #ifdef DDB
102 #include <ddb/ddb.h>
103 #endif
104 
105 static void	delmntque(struct vnode *vp);
106 static int	flushbuflist(struct bufv *bufv, int flags, struct bufobj *bo,
107 		    int slpflag, int slptimeo);
108 static void	syncer_shutdown(void *arg, int howto);
109 static int	vtryrecycle(struct vnode *vp);
110 static void	v_init_counters(struct vnode *);
111 static void	vn_seqc_init(struct vnode *);
112 static void	vn_seqc_write_end_free(struct vnode *vp);
113 static void	vgonel(struct vnode *);
114 static bool	vhold_recycle_free(struct vnode *);
115 static void	vfs_knllock(void *arg);
116 static void	vfs_knlunlock(void *arg);
117 static void	vfs_knl_assert_lock(void *arg, int what);
118 static void	destroy_vpollinfo(struct vpollinfo *vi);
119 static int	v_inval_buf_range_locked(struct vnode *vp, struct bufobj *bo,
120 		    daddr_t startlbn, daddr_t endlbn);
121 static void	vnlru_recalc(void);
122 
123 /*
124  * These fences are intended for cases where some synchronization is
125  * needed between access of v_iflags and lockless vnode refcount (v_holdcnt
126  * and v_usecount) updates.  Access to v_iflags is generally synchronized
127  * by the interlock, but we have some internal assertions that check vnode
128  * flags without acquiring the lock.  Thus, these fences are INVARIANTS-only
129  * for now.
130  */
131 #ifdef INVARIANTS
132 #define	VNODE_REFCOUNT_FENCE_ACQ()	atomic_thread_fence_acq()
133 #define	VNODE_REFCOUNT_FENCE_REL()	atomic_thread_fence_rel()
134 #else
135 #define	VNODE_REFCOUNT_FENCE_ACQ()
136 #define	VNODE_REFCOUNT_FENCE_REL()
137 #endif
138 
139 /*
140  * Number of vnodes in existence.  Increased whenever getnewvnode()
141  * allocates a new vnode, decreased in vdropl() for VIRF_DOOMED vnode.
142  */
143 static u_long __exclusive_cache_line numvnodes;
144 
145 SYSCTL_ULONG(_vfs, OID_AUTO, numvnodes, CTLFLAG_RD, &numvnodes, 0,
146     "Number of vnodes in existence");
147 
148 static counter_u64_t vnodes_created;
149 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, vnodes_created, CTLFLAG_RD, &vnodes_created,
150     "Number of vnodes created by getnewvnode");
151 
152 /*
153  * Conversion tables for conversion from vnode types to inode formats
154  * and back.
155  */
156 enum vtype iftovt_tab[16] = {
157 	VNON, VFIFO, VCHR, VNON, VDIR, VNON, VBLK, VNON,
158 	VREG, VNON, VLNK, VNON, VSOCK, VNON, VNON, VNON
159 };
160 int vttoif_tab[10] = {
161 	0, S_IFREG, S_IFDIR, S_IFBLK, S_IFCHR, S_IFLNK,
162 	S_IFSOCK, S_IFIFO, S_IFMT, S_IFMT
163 };
164 
165 /*
166  * List of allocates vnodes in the system.
167  */
168 static TAILQ_HEAD(freelst, vnode) vnode_list;
169 static struct vnode *vnode_list_free_marker;
170 static struct vnode *vnode_list_reclaim_marker;
171 
172 /*
173  * "Free" vnode target.  Free vnodes are rarely completely free, but are
174  * just ones that are cheap to recycle.  Usually they are for files which
175  * have been stat'd but not read; these usually have inode and namecache
176  * data attached to them.  This target is the preferred minimum size of a
177  * sub-cache consisting mostly of such files. The system balances the size
178  * of this sub-cache with its complement to try to prevent either from
179  * thrashing while the other is relatively inactive.  The targets express
180  * a preference for the best balance.
181  *
182  * "Above" this target there are 2 further targets (watermarks) related
183  * to recyling of free vnodes.  In the best-operating case, the cache is
184  * exactly full, the free list has size between vlowat and vhiwat above the
185  * free target, and recycling from it and normal use maintains this state.
186  * Sometimes the free list is below vlowat or even empty, but this state
187  * is even better for immediate use provided the cache is not full.
188  * Otherwise, vnlru_proc() runs to reclaim enough vnodes (usually non-free
189  * ones) to reach one of these states.  The watermarks are currently hard-
190  * coded as 4% and 9% of the available space higher.  These and the default
191  * of 25% for wantfreevnodes are too large if the memory size is large.
192  * E.g., 9% of 75% of MAXVNODES is more than 566000 vnodes to reclaim
193  * whenever vnlru_proc() becomes active.
194  */
195 static long wantfreevnodes;
196 static long __exclusive_cache_line freevnodes;
197 SYSCTL_ULONG(_vfs, OID_AUTO, freevnodes, CTLFLAG_RD,
198     &freevnodes, 0, "Number of \"free\" vnodes");
199 static long freevnodes_old;
200 
201 static counter_u64_t recycles_count;
202 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, recycles, CTLFLAG_RD, &recycles_count,
203     "Number of vnodes recycled to meet vnode cache targets");
204 
205 static counter_u64_t recycles_free_count;
206 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, recycles_free, CTLFLAG_RD, &recycles_free_count,
207     "Number of free vnodes recycled to meet vnode cache targets");
208 
209 static counter_u64_t deferred_inact;
210 SYSCTL_COUNTER_U64(_vfs, OID_AUTO, deferred_inact, CTLFLAG_RD, &deferred_inact,
211     "Number of times inactive processing was deferred");
212 
213 /* To keep more than one thread at a time from running vfs_getnewfsid */
214 static struct mtx mntid_mtx;
215 
216 /*
217  * Lock for any access to the following:
218  *	vnode_list
219  *	numvnodes
220  *	freevnodes
221  */
222 static struct mtx __exclusive_cache_line vnode_list_mtx;
223 
224 /* Publicly exported FS */
225 struct nfs_public nfs_pub;
226 
227 static uma_zone_t buf_trie_zone;
228 static smr_t buf_trie_smr;
229 
230 /* Zone for allocation of new vnodes - used exclusively by getnewvnode() */
231 static uma_zone_t vnode_zone;
232 MALLOC_DEFINE(M_VNODEPOLL, "VN POLL", "vnode poll");
233 
234 __read_frequently smr_t vfs_smr;
235 
236 /*
237  * The workitem queue.
238  *
239  * It is useful to delay writes of file data and filesystem metadata
240  * for tens of seconds so that quickly created and deleted files need
241  * not waste disk bandwidth being created and removed. To realize this,
242  * we append vnodes to a "workitem" queue. When running with a soft
243  * updates implementation, most pending metadata dependencies should
244  * not wait for more than a few seconds. Thus, mounted on block devices
245  * are delayed only about a half the time that file data is delayed.
246  * Similarly, directory updates are more critical, so are only delayed
247  * about a third the time that file data is delayed. Thus, there are
248  * SYNCER_MAXDELAY queues that are processed round-robin at a rate of
249  * one each second (driven off the filesystem syncer process). The
250  * syncer_delayno variable indicates the next queue that is to be processed.
251  * Items that need to be processed soon are placed in this queue:
252  *
253  *	syncer_workitem_pending[syncer_delayno]
254  *
255  * A delay of fifteen seconds is done by placing the request fifteen
256  * entries later in the queue:
257  *
258  *	syncer_workitem_pending[(syncer_delayno + 15) & syncer_mask]
259  *
260  */
261 static int syncer_delayno;
262 static long syncer_mask;
263 LIST_HEAD(synclist, bufobj);
264 static struct synclist *syncer_workitem_pending;
265 /*
266  * The sync_mtx protects:
267  *	bo->bo_synclist
268  *	sync_vnode_count
269  *	syncer_delayno
270  *	syncer_state
271  *	syncer_workitem_pending
272  *	syncer_worklist_len
273  *	rushjob
274  */
275 static struct mtx sync_mtx;
276 static struct cv sync_wakeup;
277 
278 #define SYNCER_MAXDELAY		32
279 static int syncer_maxdelay = SYNCER_MAXDELAY;	/* maximum delay time */
280 static int syncdelay = 30;		/* max time to delay syncing data */
281 static int filedelay = 30;		/* time to delay syncing files */
282 SYSCTL_INT(_kern, OID_AUTO, filedelay, CTLFLAG_RW, &filedelay, 0,
283     "Time to delay syncing files (in seconds)");
284 static int dirdelay = 29;		/* time to delay syncing directories */
285 SYSCTL_INT(_kern, OID_AUTO, dirdelay, CTLFLAG_RW, &dirdelay, 0,
286     "Time to delay syncing directories (in seconds)");
287 static int metadelay = 28;		/* time to delay syncing metadata */
288 SYSCTL_INT(_kern, OID_AUTO, metadelay, CTLFLAG_RW, &metadelay, 0,
289     "Time to delay syncing metadata (in seconds)");
290 static int rushjob;		/* number of slots to run ASAP */
291 static int stat_rush_requests;	/* number of times I/O speeded up */
292 SYSCTL_INT(_debug, OID_AUTO, rush_requests, CTLFLAG_RW, &stat_rush_requests, 0,
293     "Number of times I/O speeded up (rush requests)");
294 
295 #define	VDBATCH_SIZE 8
296 struct vdbatch {
297 	u_int index;
298 	long freevnodes;
299 	struct mtx lock;
300 	struct vnode *tab[VDBATCH_SIZE];
301 };
302 DPCPU_DEFINE_STATIC(struct vdbatch, vd);
303 
304 static void	vdbatch_dequeue(struct vnode *vp);
305 
306 /*
307  * When shutting down the syncer, run it at four times normal speed.
308  */
309 #define SYNCER_SHUTDOWN_SPEEDUP		4
310 static int sync_vnode_count;
311 static int syncer_worklist_len;
312 static enum { SYNCER_RUNNING, SYNCER_SHUTTING_DOWN, SYNCER_FINAL_DELAY }
313     syncer_state;
314 
315 /* Target for maximum number of vnodes. */
316 u_long desiredvnodes;
317 static u_long gapvnodes;		/* gap between wanted and desired */
318 static u_long vhiwat;		/* enough extras after expansion */
319 static u_long vlowat;		/* minimal extras before expansion */
320 static u_long vstir;		/* nonzero to stir non-free vnodes */
321 static volatile int vsmalltrigger = 8;	/* pref to keep if > this many pages */
322 
323 static u_long vnlru_read_freevnodes(void);
324 
325 /*
326  * Note that no attempt is made to sanitize these parameters.
327  */
328 static int
329 sysctl_maxvnodes(SYSCTL_HANDLER_ARGS)
330 {
331 	u_long val;
332 	int error;
333 
334 	val = desiredvnodes;
335 	error = sysctl_handle_long(oidp, &val, 0, req);
336 	if (error != 0 || req->newptr == NULL)
337 		return (error);
338 
339 	if (val == desiredvnodes)
340 		return (0);
341 	mtx_lock(&vnode_list_mtx);
342 	desiredvnodes = val;
343 	wantfreevnodes = desiredvnodes / 4;
344 	vnlru_recalc();
345 	mtx_unlock(&vnode_list_mtx);
346 	/*
347 	 * XXX There is no protection against multiple threads changing
348 	 * desiredvnodes at the same time. Locking above only helps vnlru and
349 	 * getnewvnode.
350 	 */
351 	vfs_hash_changesize(desiredvnodes);
352 	cache_changesize(desiredvnodes);
353 	return (0);
354 }
355 
356 SYSCTL_PROC(_kern, KERN_MAXVNODES, maxvnodes,
357     CTLTYPE_ULONG | CTLFLAG_MPSAFE | CTLFLAG_RW, NULL, 0, sysctl_maxvnodes,
358     "LU", "Target for maximum number of vnodes");
359 
360 static int
361 sysctl_wantfreevnodes(SYSCTL_HANDLER_ARGS)
362 {
363 	u_long val;
364 	int error;
365 
366 	val = wantfreevnodes;
367 	error = sysctl_handle_long(oidp, &val, 0, req);
368 	if (error != 0 || req->newptr == NULL)
369 		return (error);
370 
371 	if (val == wantfreevnodes)
372 		return (0);
373 	mtx_lock(&vnode_list_mtx);
374 	wantfreevnodes = val;
375 	vnlru_recalc();
376 	mtx_unlock(&vnode_list_mtx);
377 	return (0);
378 }
379 
380 SYSCTL_PROC(_vfs, OID_AUTO, wantfreevnodes,
381     CTLTYPE_ULONG | CTLFLAG_MPSAFE | CTLFLAG_RW, NULL, 0, sysctl_wantfreevnodes,
382     "LU", "Target for minimum number of \"free\" vnodes");
383 
384 SYSCTL_ULONG(_kern, OID_AUTO, minvnodes, CTLFLAG_RW,
385     &wantfreevnodes, 0, "Old name for vfs.wantfreevnodes (legacy)");
386 static int vnlru_nowhere;
387 SYSCTL_INT(_debug, OID_AUTO, vnlru_nowhere, CTLFLAG_RW,
388     &vnlru_nowhere, 0, "Number of times the vnlru process ran without success");
389 
390 static int
391 sysctl_try_reclaim_vnode(SYSCTL_HANDLER_ARGS)
392 {
393 	struct vnode *vp;
394 	struct nameidata nd;
395 	char *buf;
396 	unsigned long ndflags;
397 	int error;
398 
399 	if (req->newptr == NULL)
400 		return (EINVAL);
401 	if (req->newlen >= PATH_MAX)
402 		return (E2BIG);
403 
404 	buf = malloc(PATH_MAX, M_TEMP, M_WAITOK);
405 	error = SYSCTL_IN(req, buf, req->newlen);
406 	if (error != 0)
407 		goto out;
408 
409 	buf[req->newlen] = '\0';
410 
411 	ndflags = LOCKLEAF | NOFOLLOW | AUDITVNODE1 | SAVENAME;
412 	NDINIT(&nd, LOOKUP, ndflags, UIO_SYSSPACE, buf, curthread);
413 	if ((error = namei(&nd)) != 0)
414 		goto out;
415 	vp = nd.ni_vp;
416 
417 	if (VN_IS_DOOMED(vp)) {
418 		/*
419 		 * This vnode is being recycled.  Return != 0 to let the caller
420 		 * know that the sysctl had no effect.  Return EAGAIN because a
421 		 * subsequent call will likely succeed (since namei will create
422 		 * a new vnode if necessary)
423 		 */
424 		error = EAGAIN;
425 		goto putvnode;
426 	}
427 
428 	counter_u64_add(recycles_count, 1);
429 	vgone(vp);
430 putvnode:
431 	NDFREE(&nd, 0);
432 out:
433 	free(buf, M_TEMP);
434 	return (error);
435 }
436 
437 static int
438 sysctl_ftry_reclaim_vnode(SYSCTL_HANDLER_ARGS)
439 {
440 	struct thread *td = curthread;
441 	struct vnode *vp;
442 	struct file *fp;
443 	int error;
444 	int fd;
445 
446 	if (req->newptr == NULL)
447 		return (EBADF);
448 
449         error = sysctl_handle_int(oidp, &fd, 0, req);
450         if (error != 0)
451                 return (error);
452 	error = getvnode(curthread, fd, &cap_fcntl_rights, &fp);
453 	if (error != 0)
454 		return (error);
455 	vp = fp->f_vnode;
456 
457 	error = vn_lock(vp, LK_EXCLUSIVE);
458 	if (error != 0)
459 		goto drop;
460 
461 	counter_u64_add(recycles_count, 1);
462 	vgone(vp);
463 	VOP_UNLOCK(vp);
464 drop:
465 	fdrop(fp, td);
466 	return (error);
467 }
468 
469 SYSCTL_PROC(_debug, OID_AUTO, try_reclaim_vnode,
470     CTLTYPE_STRING | CTLFLAG_MPSAFE | CTLFLAG_WR, NULL, 0,
471     sysctl_try_reclaim_vnode, "A", "Try to reclaim a vnode by its pathname");
472 SYSCTL_PROC(_debug, OID_AUTO, ftry_reclaim_vnode,
473     CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_WR, NULL, 0,
474     sysctl_ftry_reclaim_vnode, "I",
475     "Try to reclaim a vnode by its file descriptor");
476 
477 /* Shift count for (uintptr_t)vp to initialize vp->v_hash. */
478 static int vnsz2log;
479 
480 /*
481  * Support for the bufobj clean & dirty pctrie.
482  */
483 static void *
484 buf_trie_alloc(struct pctrie *ptree)
485 {
486 	return (uma_zalloc_smr(buf_trie_zone, M_NOWAIT));
487 }
488 
489 static void
490 buf_trie_free(struct pctrie *ptree, void *node)
491 {
492 	uma_zfree_smr(buf_trie_zone, node);
493 }
494 PCTRIE_DEFINE_SMR(BUF, buf, b_lblkno, buf_trie_alloc, buf_trie_free,
495     buf_trie_smr);
496 
497 /*
498  * Initialize the vnode management data structures.
499  *
500  * Reevaluate the following cap on the number of vnodes after the physical
501  * memory size exceeds 512GB.  In the limit, as the physical memory size
502  * grows, the ratio of the memory size in KB to vnodes approaches 64:1.
503  */
504 #ifndef	MAXVNODES_MAX
505 #define	MAXVNODES_MAX	(512UL * 1024 * 1024 / 64)	/* 8M */
506 #endif
507 
508 static MALLOC_DEFINE(M_VNODE_MARKER, "vnodemarker", "vnode marker");
509 
510 static struct vnode *
511 vn_alloc_marker(struct mount *mp)
512 {
513 	struct vnode *vp;
514 
515 	vp = malloc(sizeof(struct vnode), M_VNODE_MARKER, M_WAITOK | M_ZERO);
516 	vp->v_type = VMARKER;
517 	vp->v_mount = mp;
518 
519 	return (vp);
520 }
521 
522 static void
523 vn_free_marker(struct vnode *vp)
524 {
525 
526 	MPASS(vp->v_type == VMARKER);
527 	free(vp, M_VNODE_MARKER);
528 }
529 
530 /*
531  * Initialize a vnode as it first enters the zone.
532  */
533 static int
534 vnode_init(void *mem, int size, int flags)
535 {
536 	struct vnode *vp;
537 
538 	vp = mem;
539 	bzero(vp, size);
540 	/*
541 	 * Setup locks.
542 	 */
543 	vp->v_vnlock = &vp->v_lock;
544 	mtx_init(&vp->v_interlock, "vnode interlock", NULL, MTX_DEF);
545 	/*
546 	 * By default, don't allow shared locks unless filesystems opt-in.
547 	 */
548 	lockinit(vp->v_vnlock, PVFS, "vnode", VLKTIMEOUT,
549 	    LK_NOSHARE | LK_IS_VNODE);
550 	/*
551 	 * Initialize bufobj.
552 	 */
553 	bufobj_init(&vp->v_bufobj, vp);
554 	/*
555 	 * Initialize namecache.
556 	 */
557 	cache_vnode_init(vp);
558 	/*
559 	 * Initialize rangelocks.
560 	 */
561 	rangelock_init(&vp->v_rl);
562 
563 	vp->v_dbatchcpu = NOCPU;
564 
565 	/*
566 	 * Check vhold_recycle_free for an explanation.
567 	 */
568 	vp->v_holdcnt = VHOLD_NO_SMR;
569 	vp->v_type = VNON;
570 	mtx_lock(&vnode_list_mtx);
571 	TAILQ_INSERT_BEFORE(vnode_list_free_marker, vp, v_vnodelist);
572 	mtx_unlock(&vnode_list_mtx);
573 	return (0);
574 }
575 
576 /*
577  * Free a vnode when it is cleared from the zone.
578  */
579 static void
580 vnode_fini(void *mem, int size)
581 {
582 	struct vnode *vp;
583 	struct bufobj *bo;
584 
585 	vp = mem;
586 	vdbatch_dequeue(vp);
587 	mtx_lock(&vnode_list_mtx);
588 	TAILQ_REMOVE(&vnode_list, vp, v_vnodelist);
589 	mtx_unlock(&vnode_list_mtx);
590 	rangelock_destroy(&vp->v_rl);
591 	lockdestroy(vp->v_vnlock);
592 	mtx_destroy(&vp->v_interlock);
593 	bo = &vp->v_bufobj;
594 	rw_destroy(BO_LOCKPTR(bo));
595 }
596 
597 /*
598  * Provide the size of NFS nclnode and NFS fh for calculation of the
599  * vnode memory consumption.  The size is specified directly to
600  * eliminate dependency on NFS-private header.
601  *
602  * Other filesystems may use bigger or smaller (like UFS and ZFS)
603  * private inode data, but the NFS-based estimation is ample enough.
604  * Still, we care about differences in the size between 64- and 32-bit
605  * platforms.
606  *
607  * Namecache structure size is heuristically
608  * sizeof(struct namecache_ts) + CACHE_PATH_CUTOFF + 1.
609  */
610 #ifdef _LP64
611 #define	NFS_NCLNODE_SZ	(528 + 64)
612 #define	NC_SZ		148
613 #else
614 #define	NFS_NCLNODE_SZ	(360 + 32)
615 #define	NC_SZ		92
616 #endif
617 
618 static void
619 vntblinit(void *dummy __unused)
620 {
621 	struct vdbatch *vd;
622 	int cpu, physvnodes, virtvnodes;
623 	u_int i;
624 
625 	/*
626 	 * Desiredvnodes is a function of the physical memory size and the
627 	 * kernel's heap size.  Generally speaking, it scales with the
628 	 * physical memory size.  The ratio of desiredvnodes to the physical
629 	 * memory size is 1:16 until desiredvnodes exceeds 98,304.
630 	 * Thereafter, the
631 	 * marginal ratio of desiredvnodes to the physical memory size is
632 	 * 1:64.  However, desiredvnodes is limited by the kernel's heap
633 	 * size.  The memory required by desiredvnodes vnodes and vm objects
634 	 * must not exceed 1/10th of the kernel's heap size.
635 	 */
636 	physvnodes = maxproc + pgtok(vm_cnt.v_page_count) / 64 +
637 	    3 * min(98304 * 16, pgtok(vm_cnt.v_page_count)) / 64;
638 	virtvnodes = vm_kmem_size / (10 * (sizeof(struct vm_object) +
639 	    sizeof(struct vnode) + NC_SZ * ncsizefactor + NFS_NCLNODE_SZ));
640 	desiredvnodes = min(physvnodes, virtvnodes);
641 	if (desiredvnodes > MAXVNODES_MAX) {
642 		if (bootverbose)
643 			printf("Reducing kern.maxvnodes %lu -> %lu\n",
644 			    desiredvnodes, MAXVNODES_MAX);
645 		desiredvnodes = MAXVNODES_MAX;
646 	}
647 	wantfreevnodes = desiredvnodes / 4;
648 	mtx_init(&mntid_mtx, "mntid", NULL, MTX_DEF);
649 	TAILQ_INIT(&vnode_list);
650 	mtx_init(&vnode_list_mtx, "vnode_list", NULL, MTX_DEF);
651 	/*
652 	 * The lock is taken to appease WITNESS.
653 	 */
654 	mtx_lock(&vnode_list_mtx);
655 	vnlru_recalc();
656 	mtx_unlock(&vnode_list_mtx);
657 	vnode_list_free_marker = vn_alloc_marker(NULL);
658 	TAILQ_INSERT_HEAD(&vnode_list, vnode_list_free_marker, v_vnodelist);
659 	vnode_list_reclaim_marker = vn_alloc_marker(NULL);
660 	TAILQ_INSERT_HEAD(&vnode_list, vnode_list_reclaim_marker, v_vnodelist);
661 	vnode_zone = uma_zcreate("VNODE", sizeof (struct vnode), NULL, NULL,
662 	    vnode_init, vnode_fini, UMA_ALIGN_PTR, 0);
663 	uma_zone_set_smr(vnode_zone, vfs_smr);
664 	/*
665 	 * Preallocate enough nodes to support one-per buf so that
666 	 * we can not fail an insert.  reassignbuf() callers can not
667 	 * tolerate the insertion failure.
668 	 */
669 	buf_trie_zone = uma_zcreate("BUF TRIE", pctrie_node_size(),
670 	    NULL, NULL, pctrie_zone_init, NULL, UMA_ALIGN_PTR,
671 	    UMA_ZONE_NOFREE | UMA_ZONE_SMR);
672 	buf_trie_smr = uma_zone_get_smr(buf_trie_zone);
673 	uma_prealloc(buf_trie_zone, nbuf);
674 
675 	vnodes_created = counter_u64_alloc(M_WAITOK);
676 	recycles_count = counter_u64_alloc(M_WAITOK);
677 	recycles_free_count = counter_u64_alloc(M_WAITOK);
678 	deferred_inact = counter_u64_alloc(M_WAITOK);
679 
680 	/*
681 	 * Initialize the filesystem syncer.
682 	 */
683 	syncer_workitem_pending = hashinit(syncer_maxdelay, M_VNODE,
684 	    &syncer_mask);
685 	syncer_maxdelay = syncer_mask + 1;
686 	mtx_init(&sync_mtx, "Syncer mtx", NULL, MTX_DEF);
687 	cv_init(&sync_wakeup, "syncer");
688 	for (i = 1; i <= sizeof(struct vnode); i <<= 1)
689 		vnsz2log++;
690 	vnsz2log--;
691 
692 	CPU_FOREACH(cpu) {
693 		vd = DPCPU_ID_PTR((cpu), vd);
694 		bzero(vd, sizeof(*vd));
695 		mtx_init(&vd->lock, "vdbatch", NULL, MTX_DEF);
696 	}
697 }
698 SYSINIT(vfs, SI_SUB_VFS, SI_ORDER_FIRST, vntblinit, NULL);
699 
700 /*
701  * Mark a mount point as busy. Used to synchronize access and to delay
702  * unmounting. Eventually, mountlist_mtx is not released on failure.
703  *
704  * vfs_busy() is a custom lock, it can block the caller.
705  * vfs_busy() only sleeps if the unmount is active on the mount point.
706  * For a mountpoint mp, vfs_busy-enforced lock is before lock of any
707  * vnode belonging to mp.
708  *
709  * Lookup uses vfs_busy() to traverse mount points.
710  * root fs			var fs
711  * / vnode lock		A	/ vnode lock (/var)		D
712  * /var vnode lock	B	/log vnode lock(/var/log)	E
713  * vfs_busy lock	C	vfs_busy lock			F
714  *
715  * Within each file system, the lock order is C->A->B and F->D->E.
716  *
717  * When traversing across mounts, the system follows that lock order:
718  *
719  *        C->A->B
720  *              |
721  *              +->F->D->E
722  *
723  * The lookup() process for namei("/var") illustrates the process:
724  *  VOP_LOOKUP() obtains B while A is held
725  *  vfs_busy() obtains a shared lock on F while A and B are held
726  *  vput() releases lock on B
727  *  vput() releases lock on A
728  *  VFS_ROOT() obtains lock on D while shared lock on F is held
729  *  vfs_unbusy() releases shared lock on F
730  *  vn_lock() obtains lock on deadfs vnode vp_crossmp instead of A.
731  *    Attempt to lock A (instead of vp_crossmp) while D is held would
732  *    violate the global order, causing deadlocks.
733  *
734  * dounmount() locks B while F is drained.
735  */
736 int
737 vfs_busy(struct mount *mp, int flags)
738 {
739 	struct mount_pcpu *mpcpu;
740 
741 	MPASS((flags & ~MBF_MASK) == 0);
742 	CTR3(KTR_VFS, "%s: mp %p with flags %d", __func__, mp, flags);
743 
744 	if (vfs_op_thread_enter(mp, mpcpu)) {
745 		MPASS((mp->mnt_kern_flag & MNTK_DRAINING) == 0);
746 		MPASS((mp->mnt_kern_flag & MNTK_UNMOUNT) == 0);
747 		MPASS((mp->mnt_kern_flag & MNTK_REFEXPIRE) == 0);
748 		vfs_mp_count_add_pcpu(mpcpu, ref, 1);
749 		vfs_mp_count_add_pcpu(mpcpu, lockref, 1);
750 		vfs_op_thread_exit(mp, mpcpu);
751 		if (flags & MBF_MNTLSTLOCK)
752 			mtx_unlock(&mountlist_mtx);
753 		return (0);
754 	}
755 
756 	MNT_ILOCK(mp);
757 	vfs_assert_mount_counters(mp);
758 	MNT_REF(mp);
759 	/*
760 	 * If mount point is currently being unmounted, sleep until the
761 	 * mount point fate is decided.  If thread doing the unmounting fails,
762 	 * it will clear MNTK_UNMOUNT flag before waking us up, indicating
763 	 * that this mount point has survived the unmount attempt and vfs_busy
764 	 * should retry.  Otherwise the unmounter thread will set MNTK_REFEXPIRE
765 	 * flag in addition to MNTK_UNMOUNT, indicating that mount point is
766 	 * about to be really destroyed.  vfs_busy needs to release its
767 	 * reference on the mount point in this case and return with ENOENT,
768 	 * telling the caller that mount mount it tried to busy is no longer
769 	 * valid.
770 	 */
771 	while (mp->mnt_kern_flag & MNTK_UNMOUNT) {
772 		if (flags & MBF_NOWAIT || mp->mnt_kern_flag & MNTK_REFEXPIRE) {
773 			MNT_REL(mp);
774 			MNT_IUNLOCK(mp);
775 			CTR1(KTR_VFS, "%s: failed busying before sleeping",
776 			    __func__);
777 			return (ENOENT);
778 		}
779 		if (flags & MBF_MNTLSTLOCK)
780 			mtx_unlock(&mountlist_mtx);
781 		mp->mnt_kern_flag |= MNTK_MWAIT;
782 		msleep(mp, MNT_MTX(mp), PVFS | PDROP, "vfs_busy", 0);
783 		if (flags & MBF_MNTLSTLOCK)
784 			mtx_lock(&mountlist_mtx);
785 		MNT_ILOCK(mp);
786 	}
787 	if (flags & MBF_MNTLSTLOCK)
788 		mtx_unlock(&mountlist_mtx);
789 	mp->mnt_lockref++;
790 	MNT_IUNLOCK(mp);
791 	return (0);
792 }
793 
794 /*
795  * Free a busy filesystem.
796  */
797 void
798 vfs_unbusy(struct mount *mp)
799 {
800 	struct mount_pcpu *mpcpu;
801 	int c;
802 
803 	CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
804 
805 	if (vfs_op_thread_enter(mp, mpcpu)) {
806 		MPASS((mp->mnt_kern_flag & MNTK_DRAINING) == 0);
807 		vfs_mp_count_sub_pcpu(mpcpu, lockref, 1);
808 		vfs_mp_count_sub_pcpu(mpcpu, ref, 1);
809 		vfs_op_thread_exit(mp, mpcpu);
810 		return;
811 	}
812 
813 	MNT_ILOCK(mp);
814 	vfs_assert_mount_counters(mp);
815 	MNT_REL(mp);
816 	c = --mp->mnt_lockref;
817 	if (mp->mnt_vfs_ops == 0) {
818 		MPASS((mp->mnt_kern_flag & MNTK_DRAINING) == 0);
819 		MNT_IUNLOCK(mp);
820 		return;
821 	}
822 	if (c < 0)
823 		vfs_dump_mount_counters(mp);
824 	if (c == 0 && (mp->mnt_kern_flag & MNTK_DRAINING) != 0) {
825 		MPASS(mp->mnt_kern_flag & MNTK_UNMOUNT);
826 		CTR1(KTR_VFS, "%s: waking up waiters", __func__);
827 		mp->mnt_kern_flag &= ~MNTK_DRAINING;
828 		wakeup(&mp->mnt_lockref);
829 	}
830 	MNT_IUNLOCK(mp);
831 }
832 
833 /*
834  * Lookup a mount point by filesystem identifier.
835  */
836 struct mount *
837 vfs_getvfs(fsid_t *fsid)
838 {
839 	struct mount *mp;
840 
841 	CTR2(KTR_VFS, "%s: fsid %p", __func__, fsid);
842 	mtx_lock(&mountlist_mtx);
843 	TAILQ_FOREACH(mp, &mountlist, mnt_list) {
844 		if (fsidcmp(&mp->mnt_stat.f_fsid, fsid) == 0) {
845 			vfs_ref(mp);
846 			mtx_unlock(&mountlist_mtx);
847 			return (mp);
848 		}
849 	}
850 	mtx_unlock(&mountlist_mtx);
851 	CTR2(KTR_VFS, "%s: lookup failed for %p id", __func__, fsid);
852 	return ((struct mount *) 0);
853 }
854 
855 /*
856  * Lookup a mount point by filesystem identifier, busying it before
857  * returning.
858  *
859  * To avoid congestion on mountlist_mtx, implement simple direct-mapped
860  * cache for popular filesystem identifiers.  The cache is lockess, using
861  * the fact that struct mount's are never freed.  In worst case we may
862  * get pointer to unmounted or even different filesystem, so we have to
863  * check what we got, and go slow way if so.
864  */
865 struct mount *
866 vfs_busyfs(fsid_t *fsid)
867 {
868 #define	FSID_CACHE_SIZE	256
869 	typedef struct mount * volatile vmp_t;
870 	static vmp_t cache[FSID_CACHE_SIZE];
871 	struct mount *mp;
872 	int error;
873 	uint32_t hash;
874 
875 	CTR2(KTR_VFS, "%s: fsid %p", __func__, fsid);
876 	hash = fsid->val[0] ^ fsid->val[1];
877 	hash = (hash >> 16 ^ hash) & (FSID_CACHE_SIZE - 1);
878 	mp = cache[hash];
879 	if (mp == NULL || fsidcmp(&mp->mnt_stat.f_fsid, fsid) != 0)
880 		goto slow;
881 	if (vfs_busy(mp, 0) != 0) {
882 		cache[hash] = NULL;
883 		goto slow;
884 	}
885 	if (fsidcmp(&mp->mnt_stat.f_fsid, fsid) == 0)
886 		return (mp);
887 	else
888 	    vfs_unbusy(mp);
889 
890 slow:
891 	mtx_lock(&mountlist_mtx);
892 	TAILQ_FOREACH(mp, &mountlist, mnt_list) {
893 		if (fsidcmp(&mp->mnt_stat.f_fsid, fsid) == 0) {
894 			error = vfs_busy(mp, MBF_MNTLSTLOCK);
895 			if (error) {
896 				cache[hash] = NULL;
897 				mtx_unlock(&mountlist_mtx);
898 				return (NULL);
899 			}
900 			cache[hash] = mp;
901 			return (mp);
902 		}
903 	}
904 	CTR2(KTR_VFS, "%s: lookup failed for %p id", __func__, fsid);
905 	mtx_unlock(&mountlist_mtx);
906 	return ((struct mount *) 0);
907 }
908 
909 /*
910  * Check if a user can access privileged mount options.
911  */
912 int
913 vfs_suser(struct mount *mp, struct thread *td)
914 {
915 	int error;
916 
917 	if (jailed(td->td_ucred)) {
918 		/*
919 		 * If the jail of the calling thread lacks permission for
920 		 * this type of file system, deny immediately.
921 		 */
922 		if (!prison_allow(td->td_ucred, mp->mnt_vfc->vfc_prison_flag))
923 			return (EPERM);
924 
925 		/*
926 		 * If the file system was mounted outside the jail of the
927 		 * calling thread, deny immediately.
928 		 */
929 		if (prison_check(td->td_ucred, mp->mnt_cred) != 0)
930 			return (EPERM);
931 	}
932 
933 	/*
934 	 * If file system supports delegated administration, we don't check
935 	 * for the PRIV_VFS_MOUNT_OWNER privilege - it will be better verified
936 	 * by the file system itself.
937 	 * If this is not the user that did original mount, we check for
938 	 * the PRIV_VFS_MOUNT_OWNER privilege.
939 	 */
940 	if (!(mp->mnt_vfc->vfc_flags & VFCF_DELEGADMIN) &&
941 	    mp->mnt_cred->cr_uid != td->td_ucred->cr_uid) {
942 		if ((error = priv_check(td, PRIV_VFS_MOUNT_OWNER)) != 0)
943 			return (error);
944 	}
945 	return (0);
946 }
947 
948 /*
949  * Get a new unique fsid.  Try to make its val[0] unique, since this value
950  * will be used to create fake device numbers for stat().  Also try (but
951  * not so hard) make its val[0] unique mod 2^16, since some emulators only
952  * support 16-bit device numbers.  We end up with unique val[0]'s for the
953  * first 2^16 calls and unique val[0]'s mod 2^16 for the first 2^8 calls.
954  *
955  * Keep in mind that several mounts may be running in parallel.  Starting
956  * the search one past where the previous search terminated is both a
957  * micro-optimization and a defense against returning the same fsid to
958  * different mounts.
959  */
960 void
961 vfs_getnewfsid(struct mount *mp)
962 {
963 	static uint16_t mntid_base;
964 	struct mount *nmp;
965 	fsid_t tfsid;
966 	int mtype;
967 
968 	CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
969 	mtx_lock(&mntid_mtx);
970 	mtype = mp->mnt_vfc->vfc_typenum;
971 	tfsid.val[1] = mtype;
972 	mtype = (mtype & 0xFF) << 24;
973 	for (;;) {
974 		tfsid.val[0] = makedev(255,
975 		    mtype | ((mntid_base & 0xFF00) << 8) | (mntid_base & 0xFF));
976 		mntid_base++;
977 		if ((nmp = vfs_getvfs(&tfsid)) == NULL)
978 			break;
979 		vfs_rel(nmp);
980 	}
981 	mp->mnt_stat.f_fsid.val[0] = tfsid.val[0];
982 	mp->mnt_stat.f_fsid.val[1] = tfsid.val[1];
983 	mtx_unlock(&mntid_mtx);
984 }
985 
986 /*
987  * Knob to control the precision of file timestamps:
988  *
989  *   0 = seconds only; nanoseconds zeroed.
990  *   1 = seconds and nanoseconds, accurate within 1/HZ.
991  *   2 = seconds and nanoseconds, truncated to microseconds.
992  * >=3 = seconds and nanoseconds, maximum precision.
993  */
994 enum { TSP_SEC, TSP_HZ, TSP_USEC, TSP_NSEC };
995 
996 static int timestamp_precision = TSP_USEC;
997 SYSCTL_INT(_vfs, OID_AUTO, timestamp_precision, CTLFLAG_RW,
998     &timestamp_precision, 0, "File timestamp precision (0: seconds, "
999     "1: sec + ns accurate to 1/HZ, 2: sec + ns truncated to us, "
1000     "3+: sec + ns (max. precision))");
1001 
1002 /*
1003  * Get a current timestamp.
1004  */
1005 void
1006 vfs_timestamp(struct timespec *tsp)
1007 {
1008 	struct timeval tv;
1009 
1010 	switch (timestamp_precision) {
1011 	case TSP_SEC:
1012 		tsp->tv_sec = time_second;
1013 		tsp->tv_nsec = 0;
1014 		break;
1015 	case TSP_HZ:
1016 		getnanotime(tsp);
1017 		break;
1018 	case TSP_USEC:
1019 		microtime(&tv);
1020 		TIMEVAL_TO_TIMESPEC(&tv, tsp);
1021 		break;
1022 	case TSP_NSEC:
1023 	default:
1024 		nanotime(tsp);
1025 		break;
1026 	}
1027 }
1028 
1029 /*
1030  * Set vnode attributes to VNOVAL
1031  */
1032 void
1033 vattr_null(struct vattr *vap)
1034 {
1035 
1036 	vap->va_type = VNON;
1037 	vap->va_size = VNOVAL;
1038 	vap->va_bytes = VNOVAL;
1039 	vap->va_mode = VNOVAL;
1040 	vap->va_nlink = VNOVAL;
1041 	vap->va_uid = VNOVAL;
1042 	vap->va_gid = VNOVAL;
1043 	vap->va_fsid = VNOVAL;
1044 	vap->va_fileid = VNOVAL;
1045 	vap->va_blocksize = VNOVAL;
1046 	vap->va_rdev = VNOVAL;
1047 	vap->va_atime.tv_sec = VNOVAL;
1048 	vap->va_atime.tv_nsec = VNOVAL;
1049 	vap->va_mtime.tv_sec = VNOVAL;
1050 	vap->va_mtime.tv_nsec = VNOVAL;
1051 	vap->va_ctime.tv_sec = VNOVAL;
1052 	vap->va_ctime.tv_nsec = VNOVAL;
1053 	vap->va_birthtime.tv_sec = VNOVAL;
1054 	vap->va_birthtime.tv_nsec = VNOVAL;
1055 	vap->va_flags = VNOVAL;
1056 	vap->va_gen = VNOVAL;
1057 	vap->va_vaflags = 0;
1058 }
1059 
1060 /*
1061  * Try to reduce the total number of vnodes.
1062  *
1063  * This routine (and its user) are buggy in at least the following ways:
1064  * - all parameters were picked years ago when RAM sizes were significantly
1065  *   smaller
1066  * - it can pick vnodes based on pages used by the vm object, but filesystems
1067  *   like ZFS don't use it making the pick broken
1068  * - since ZFS has its own aging policy it gets partially combated by this one
1069  * - a dedicated method should be provided for filesystems to let them decide
1070  *   whether the vnode should be recycled
1071  *
1072  * This routine is called when we have too many vnodes.  It attempts
1073  * to free <count> vnodes and will potentially free vnodes that still
1074  * have VM backing store (VM backing store is typically the cause
1075  * of a vnode blowout so we want to do this).  Therefore, this operation
1076  * is not considered cheap.
1077  *
1078  * A number of conditions may prevent a vnode from being reclaimed.
1079  * the buffer cache may have references on the vnode, a directory
1080  * vnode may still have references due to the namei cache representing
1081  * underlying files, or the vnode may be in active use.   It is not
1082  * desirable to reuse such vnodes.  These conditions may cause the
1083  * number of vnodes to reach some minimum value regardless of what
1084  * you set kern.maxvnodes to.  Do not set kern.maxvnodes too low.
1085  *
1086  * @param reclaim_nc_src Only reclaim directories with outgoing namecache
1087  * 			 entries if this argument is strue
1088  * @param trigger	 Only reclaim vnodes with fewer than this many resident
1089  *			 pages.
1090  * @param target	 How many vnodes to reclaim.
1091  * @return		 The number of vnodes that were reclaimed.
1092  */
1093 static int
1094 vlrureclaim(bool reclaim_nc_src, int trigger, u_long target)
1095 {
1096 	struct vnode *vp, *mvp;
1097 	struct mount *mp;
1098 	struct vm_object *object;
1099 	u_long done;
1100 	bool retried;
1101 
1102 	mtx_assert(&vnode_list_mtx, MA_OWNED);
1103 
1104 	retried = false;
1105 	done = 0;
1106 
1107 	mvp = vnode_list_reclaim_marker;
1108 restart:
1109 	vp = mvp;
1110 	while (done < target) {
1111 		vp = TAILQ_NEXT(vp, v_vnodelist);
1112 		if (__predict_false(vp == NULL))
1113 			break;
1114 
1115 		if (__predict_false(vp->v_type == VMARKER))
1116 			continue;
1117 
1118 		/*
1119 		 * If it's been deconstructed already, it's still
1120 		 * referenced, or it exceeds the trigger, skip it.
1121 		 * Also skip free vnodes.  We are trying to make space
1122 		 * to expand the free list, not reduce it.
1123 		 */
1124 		if (vp->v_usecount > 0 || vp->v_holdcnt == 0 ||
1125 		    (!reclaim_nc_src && !LIST_EMPTY(&vp->v_cache_src)))
1126 			goto next_iter;
1127 
1128 		if (vp->v_type == VBAD || vp->v_type == VNON)
1129 			goto next_iter;
1130 
1131 		object = atomic_load_ptr(&vp->v_object);
1132 		if (object == NULL || object->resident_page_count > trigger) {
1133 			goto next_iter;
1134 		}
1135 
1136 		/*
1137 		 * Handle races against vnode allocation. Filesystems lock the
1138 		 * vnode some time after it gets returned from getnewvnode,
1139 		 * despite type and hold count being manipulated earlier.
1140 		 * Resorting to checking v_mount restores guarantees present
1141 		 * before the global list was reworked to contain all vnodes.
1142 		 */
1143 		if (!VI_TRYLOCK(vp))
1144 			goto next_iter;
1145 		if (__predict_false(vp->v_type == VBAD || vp->v_type == VNON)) {
1146 			VI_UNLOCK(vp);
1147 			goto next_iter;
1148 		}
1149 		if (vp->v_mount == NULL) {
1150 			VI_UNLOCK(vp);
1151 			goto next_iter;
1152 		}
1153 		vholdl(vp);
1154 		VI_UNLOCK(vp);
1155 		TAILQ_REMOVE(&vnode_list, mvp, v_vnodelist);
1156 		TAILQ_INSERT_AFTER(&vnode_list, vp, mvp, v_vnodelist);
1157 		mtx_unlock(&vnode_list_mtx);
1158 
1159 		if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
1160 			vdrop(vp);
1161 			goto next_iter_unlocked;
1162 		}
1163 		if (VOP_LOCK(vp, LK_EXCLUSIVE|LK_NOWAIT) != 0) {
1164 			vdrop(vp);
1165 			vn_finished_write(mp);
1166 			goto next_iter_unlocked;
1167 		}
1168 
1169 		VI_LOCK(vp);
1170 		if (vp->v_usecount > 0 ||
1171 		    (!reclaim_nc_src && !LIST_EMPTY(&vp->v_cache_src)) ||
1172 		    (vp->v_object != NULL && vp->v_object->handle == vp &&
1173 		    vp->v_object->resident_page_count > trigger)) {
1174 			VOP_UNLOCK(vp);
1175 			vdropl(vp);
1176 			vn_finished_write(mp);
1177 			goto next_iter_unlocked;
1178 		}
1179 		counter_u64_add(recycles_count, 1);
1180 		vgonel(vp);
1181 		VOP_UNLOCK(vp);
1182 		vdropl(vp);
1183 		vn_finished_write(mp);
1184 		done++;
1185 next_iter_unlocked:
1186 		if (should_yield())
1187 			kern_yield(PRI_USER);
1188 		mtx_lock(&vnode_list_mtx);
1189 		goto restart;
1190 next_iter:
1191 		MPASS(vp->v_type != VMARKER);
1192 		if (!should_yield())
1193 			continue;
1194 		TAILQ_REMOVE(&vnode_list, mvp, v_vnodelist);
1195 		TAILQ_INSERT_AFTER(&vnode_list, vp, mvp, v_vnodelist);
1196 		mtx_unlock(&vnode_list_mtx);
1197 		kern_yield(PRI_USER);
1198 		mtx_lock(&vnode_list_mtx);
1199 		goto restart;
1200 	}
1201 	if (done == 0 && !retried) {
1202 		TAILQ_REMOVE(&vnode_list, mvp, v_vnodelist);
1203 		TAILQ_INSERT_HEAD(&vnode_list, mvp, v_vnodelist);
1204 		retried = true;
1205 		goto restart;
1206 	}
1207 	return (done);
1208 }
1209 
1210 static int max_vnlru_free = 10000; /* limit on vnode free requests per call */
1211 SYSCTL_INT(_debug, OID_AUTO, max_vnlru_free, CTLFLAG_RW, &max_vnlru_free,
1212     0,
1213     "limit on vnode free requests per call to the vnlru_free routine");
1214 
1215 /*
1216  * Attempt to reduce the free list by the requested amount.
1217  */
1218 static int
1219 vnlru_free_impl(int count, struct vfsops *mnt_op, struct vnode *mvp)
1220 {
1221 	struct vnode *vp;
1222 	struct mount *mp;
1223 	int ocount;
1224 
1225 	mtx_assert(&vnode_list_mtx, MA_OWNED);
1226 	if (count > max_vnlru_free)
1227 		count = max_vnlru_free;
1228 	ocount = count;
1229 	vp = mvp;
1230 	for (;;) {
1231 		if (count == 0) {
1232 			break;
1233 		}
1234 		vp = TAILQ_NEXT(vp, v_vnodelist);
1235 		if (__predict_false(vp == NULL)) {
1236 			TAILQ_REMOVE(&vnode_list, mvp, v_vnodelist);
1237 			TAILQ_INSERT_TAIL(&vnode_list, mvp, v_vnodelist);
1238 			break;
1239 		}
1240 		if (__predict_false(vp->v_type == VMARKER))
1241 			continue;
1242 		if (vp->v_holdcnt > 0)
1243 			continue;
1244 		/*
1245 		 * Don't recycle if our vnode is from different type
1246 		 * of mount point.  Note that mp is type-safe, the
1247 		 * check does not reach unmapped address even if
1248 		 * vnode is reclaimed.
1249 		 */
1250 		if (mnt_op != NULL && (mp = vp->v_mount) != NULL &&
1251 		    mp->mnt_op != mnt_op) {
1252 			continue;
1253 		}
1254 		if (__predict_false(vp->v_type == VBAD || vp->v_type == VNON)) {
1255 			continue;
1256 		}
1257 		if (!vhold_recycle_free(vp))
1258 			continue;
1259 		TAILQ_REMOVE(&vnode_list, mvp, v_vnodelist);
1260 		TAILQ_INSERT_AFTER(&vnode_list, vp, mvp, v_vnodelist);
1261 		mtx_unlock(&vnode_list_mtx);
1262 		if (vtryrecycle(vp) == 0)
1263 			count--;
1264 		mtx_lock(&vnode_list_mtx);
1265 		vp = mvp;
1266 	}
1267 	return (ocount - count);
1268 }
1269 
1270 static int
1271 vnlru_free_locked(int count)
1272 {
1273 
1274 	mtx_assert(&vnode_list_mtx, MA_OWNED);
1275 	return (vnlru_free_impl(count, NULL, vnode_list_free_marker));
1276 }
1277 
1278 void
1279 vnlru_free_vfsops(int count, struct vfsops *mnt_op, struct vnode *mvp)
1280 {
1281 
1282 	MPASS(mnt_op != NULL);
1283 	MPASS(mvp != NULL);
1284 	VNPASS(mvp->v_type == VMARKER, mvp);
1285 	mtx_lock(&vnode_list_mtx);
1286 	vnlru_free_impl(count, mnt_op, mvp);
1287 	mtx_unlock(&vnode_list_mtx);
1288 }
1289 
1290 /*
1291  * Temporary binary compat, don't use. Call vnlru_free_vfsops instead.
1292  */
1293 void
1294 vnlru_free(int count, struct vfsops *mnt_op)
1295 {
1296 	struct vnode *mvp;
1297 
1298 	if (count == 0)
1299 		return;
1300 	mtx_lock(&vnode_list_mtx);
1301 	mvp = vnode_list_free_marker;
1302 	if (vnlru_free_impl(count, mnt_op, mvp) == 0) {
1303 		/*
1304 		 * It is possible the marker was moved over eligible vnodes by
1305 		 * callers which filtered by different ops. If so, start from
1306 		 * scratch.
1307 		 */
1308 		if (vnlru_read_freevnodes() > 0) {
1309 			TAILQ_REMOVE(&vnode_list, mvp, v_vnodelist);
1310 			TAILQ_INSERT_HEAD(&vnode_list, mvp, v_vnodelist);
1311 		}
1312 		vnlru_free_impl(count, mnt_op, mvp);
1313 	}
1314 	mtx_unlock(&vnode_list_mtx);
1315 }
1316 
1317 struct vnode *
1318 vnlru_alloc_marker(void)
1319 {
1320 	struct vnode *mvp;
1321 
1322 	mvp = vn_alloc_marker(NULL);
1323 	mtx_lock(&vnode_list_mtx);
1324 	TAILQ_INSERT_BEFORE(vnode_list_free_marker, mvp, v_vnodelist);
1325 	mtx_unlock(&vnode_list_mtx);
1326 	return (mvp);
1327 }
1328 
1329 void
1330 vnlru_free_marker(struct vnode *mvp)
1331 {
1332 	mtx_lock(&vnode_list_mtx);
1333 	TAILQ_REMOVE(&vnode_list, mvp, v_vnodelist);
1334 	mtx_unlock(&vnode_list_mtx);
1335 	vn_free_marker(mvp);
1336 }
1337 
1338 static void
1339 vnlru_recalc(void)
1340 {
1341 
1342 	mtx_assert(&vnode_list_mtx, MA_OWNED);
1343 	gapvnodes = imax(desiredvnodes - wantfreevnodes, 100);
1344 	vhiwat = gapvnodes / 11; /* 9% -- just under the 10% in vlrureclaim() */
1345 	vlowat = vhiwat / 2;
1346 }
1347 
1348 /*
1349  * Attempt to recycle vnodes in a context that is always safe to block.
1350  * Calling vlrurecycle() from the bowels of filesystem code has some
1351  * interesting deadlock problems.
1352  */
1353 static struct proc *vnlruproc;
1354 static int vnlruproc_sig;
1355 
1356 /*
1357  * The main freevnodes counter is only updated when threads requeue their vnode
1358  * batches. CPUs are conditionally walked to compute a more accurate total.
1359  *
1360  * Limit how much of a slop are we willing to tolerate. Note: the actual value
1361  * at any given moment can still exceed slop, but it should not be by significant
1362  * margin in practice.
1363  */
1364 #define VNLRU_FREEVNODES_SLOP 128
1365 
1366 static __inline void
1367 vn_freevnodes_inc(void)
1368 {
1369 	struct vdbatch *vd;
1370 
1371 	critical_enter();
1372 	vd = DPCPU_PTR(vd);
1373 	vd->freevnodes++;
1374 	critical_exit();
1375 }
1376 
1377 static __inline void
1378 vn_freevnodes_dec(void)
1379 {
1380 	struct vdbatch *vd;
1381 
1382 	critical_enter();
1383 	vd = DPCPU_PTR(vd);
1384 	vd->freevnodes--;
1385 	critical_exit();
1386 }
1387 
1388 static u_long
1389 vnlru_read_freevnodes(void)
1390 {
1391 	struct vdbatch *vd;
1392 	long slop;
1393 	int cpu;
1394 
1395 	mtx_assert(&vnode_list_mtx, MA_OWNED);
1396 	if (freevnodes > freevnodes_old)
1397 		slop = freevnodes - freevnodes_old;
1398 	else
1399 		slop = freevnodes_old - freevnodes;
1400 	if (slop < VNLRU_FREEVNODES_SLOP)
1401 		return (freevnodes >= 0 ? freevnodes : 0);
1402 	freevnodes_old = freevnodes;
1403 	CPU_FOREACH(cpu) {
1404 		vd = DPCPU_ID_PTR((cpu), vd);
1405 		freevnodes_old += vd->freevnodes;
1406 	}
1407 	return (freevnodes_old >= 0 ? freevnodes_old : 0);
1408 }
1409 
1410 static bool
1411 vnlru_under(u_long rnumvnodes, u_long limit)
1412 {
1413 	u_long rfreevnodes, space;
1414 
1415 	if (__predict_false(rnumvnodes > desiredvnodes))
1416 		return (true);
1417 
1418 	space = desiredvnodes - rnumvnodes;
1419 	if (space < limit) {
1420 		rfreevnodes = vnlru_read_freevnodes();
1421 		if (rfreevnodes > wantfreevnodes)
1422 			space += rfreevnodes - wantfreevnodes;
1423 	}
1424 	return (space < limit);
1425 }
1426 
1427 static bool
1428 vnlru_under_unlocked(u_long rnumvnodes, u_long limit)
1429 {
1430 	long rfreevnodes, space;
1431 
1432 	if (__predict_false(rnumvnodes > desiredvnodes))
1433 		return (true);
1434 
1435 	space = desiredvnodes - rnumvnodes;
1436 	if (space < limit) {
1437 		rfreevnodes = atomic_load_long(&freevnodes);
1438 		if (rfreevnodes > wantfreevnodes)
1439 			space += rfreevnodes - wantfreevnodes;
1440 	}
1441 	return (space < limit);
1442 }
1443 
1444 static void
1445 vnlru_kick(void)
1446 {
1447 
1448 	mtx_assert(&vnode_list_mtx, MA_OWNED);
1449 	if (vnlruproc_sig == 0) {
1450 		vnlruproc_sig = 1;
1451 		wakeup(vnlruproc);
1452 	}
1453 }
1454 
1455 static void
1456 vnlru_proc(void)
1457 {
1458 	u_long rnumvnodes, rfreevnodes, target;
1459 	unsigned long onumvnodes;
1460 	int done, force, trigger, usevnodes;
1461 	bool reclaim_nc_src, want_reread;
1462 
1463 	EVENTHANDLER_REGISTER(shutdown_pre_sync, kproc_shutdown, vnlruproc,
1464 	    SHUTDOWN_PRI_FIRST);
1465 
1466 	force = 0;
1467 	want_reread = false;
1468 	for (;;) {
1469 		kproc_suspend_check(vnlruproc);
1470 		mtx_lock(&vnode_list_mtx);
1471 		rnumvnodes = atomic_load_long(&numvnodes);
1472 
1473 		if (want_reread) {
1474 			force = vnlru_under(numvnodes, vhiwat) ? 1 : 0;
1475 			want_reread = false;
1476 		}
1477 
1478 		/*
1479 		 * If numvnodes is too large (due to desiredvnodes being
1480 		 * adjusted using its sysctl, or emergency growth), first
1481 		 * try to reduce it by discarding from the free list.
1482 		 */
1483 		if (rnumvnodes > desiredvnodes) {
1484 			vnlru_free_locked(rnumvnodes - desiredvnodes);
1485 			rnumvnodes = atomic_load_long(&numvnodes);
1486 		}
1487 		/*
1488 		 * Sleep if the vnode cache is in a good state.  This is
1489 		 * when it is not over-full and has space for about a 4%
1490 		 * or 9% expansion (by growing its size or inexcessively
1491 		 * reducing its free list).  Otherwise, try to reclaim
1492 		 * space for a 10% expansion.
1493 		 */
1494 		if (vstir && force == 0) {
1495 			force = 1;
1496 			vstir = 0;
1497 		}
1498 		if (force == 0 && !vnlru_under(rnumvnodes, vlowat)) {
1499 			vnlruproc_sig = 0;
1500 			wakeup(&vnlruproc_sig);
1501 			msleep(vnlruproc, &vnode_list_mtx,
1502 			    PVFS|PDROP, "vlruwt", hz);
1503 			continue;
1504 		}
1505 		rfreevnodes = vnlru_read_freevnodes();
1506 
1507 		onumvnodes = rnumvnodes;
1508 		/*
1509 		 * Calculate parameters for recycling.  These are the same
1510 		 * throughout the loop to give some semblance of fairness.
1511 		 * The trigger point is to avoid recycling vnodes with lots
1512 		 * of resident pages.  We aren't trying to free memory; we
1513 		 * are trying to recycle or at least free vnodes.
1514 		 */
1515 		if (rnumvnodes <= desiredvnodes)
1516 			usevnodes = rnumvnodes - rfreevnodes;
1517 		else
1518 			usevnodes = rnumvnodes;
1519 		if (usevnodes <= 0)
1520 			usevnodes = 1;
1521 		/*
1522 		 * The trigger value is is chosen to give a conservatively
1523 		 * large value to ensure that it alone doesn't prevent
1524 		 * making progress.  The value can easily be so large that
1525 		 * it is effectively infinite in some congested and
1526 		 * misconfigured cases, and this is necessary.  Normally
1527 		 * it is about 8 to 100 (pages), which is quite large.
1528 		 */
1529 		trigger = vm_cnt.v_page_count * 2 / usevnodes;
1530 		if (force < 2)
1531 			trigger = vsmalltrigger;
1532 		reclaim_nc_src = force >= 3;
1533 		target = rnumvnodes * (int64_t)gapvnodes / imax(desiredvnodes, 1);
1534 		target = target / 10 + 1;
1535 		done = vlrureclaim(reclaim_nc_src, trigger, target);
1536 		mtx_unlock(&vnode_list_mtx);
1537 		if (onumvnodes > desiredvnodes && numvnodes <= desiredvnodes)
1538 			uma_reclaim(UMA_RECLAIM_DRAIN);
1539 		if (done == 0) {
1540 			if (force == 0 || force == 1) {
1541 				force = 2;
1542 				continue;
1543 			}
1544 			if (force == 2) {
1545 				force = 3;
1546 				continue;
1547 			}
1548 			want_reread = true;
1549 			force = 0;
1550 			vnlru_nowhere++;
1551 			tsleep(vnlruproc, PPAUSE, "vlrup", hz * 3);
1552 		} else {
1553 			want_reread = true;
1554 			kern_yield(PRI_USER);
1555 		}
1556 	}
1557 }
1558 
1559 static struct kproc_desc vnlru_kp = {
1560 	"vnlru",
1561 	vnlru_proc,
1562 	&vnlruproc
1563 };
1564 SYSINIT(vnlru, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start,
1565     &vnlru_kp);
1566 
1567 /*
1568  * Routines having to do with the management of the vnode table.
1569  */
1570 
1571 /*
1572  * Try to recycle a freed vnode.  We abort if anyone picks up a reference
1573  * before we actually vgone().  This function must be called with the vnode
1574  * held to prevent the vnode from being returned to the free list midway
1575  * through vgone().
1576  */
1577 static int
1578 vtryrecycle(struct vnode *vp)
1579 {
1580 	struct mount *vnmp;
1581 
1582 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
1583 	VNASSERT(vp->v_holdcnt, vp,
1584 	    ("vtryrecycle: Recycling vp %p without a reference.", vp));
1585 	/*
1586 	 * This vnode may found and locked via some other list, if so we
1587 	 * can't recycle it yet.
1588 	 */
1589 	if (VOP_LOCK(vp, LK_EXCLUSIVE | LK_NOWAIT) != 0) {
1590 		CTR2(KTR_VFS,
1591 		    "%s: impossible to recycle, vp %p lock is already held",
1592 		    __func__, vp);
1593 		vdrop(vp);
1594 		return (EWOULDBLOCK);
1595 	}
1596 	/*
1597 	 * Don't recycle if its filesystem is being suspended.
1598 	 */
1599 	if (vn_start_write(vp, &vnmp, V_NOWAIT) != 0) {
1600 		VOP_UNLOCK(vp);
1601 		CTR2(KTR_VFS,
1602 		    "%s: impossible to recycle, cannot start the write for %p",
1603 		    __func__, vp);
1604 		vdrop(vp);
1605 		return (EBUSY);
1606 	}
1607 	/*
1608 	 * If we got this far, we need to acquire the interlock and see if
1609 	 * anyone picked up this vnode from another list.  If not, we will
1610 	 * mark it with DOOMED via vgonel() so that anyone who does find it
1611 	 * will skip over it.
1612 	 */
1613 	VI_LOCK(vp);
1614 	if (vp->v_usecount) {
1615 		VOP_UNLOCK(vp);
1616 		vdropl(vp);
1617 		vn_finished_write(vnmp);
1618 		CTR2(KTR_VFS,
1619 		    "%s: impossible to recycle, %p is already referenced",
1620 		    __func__, vp);
1621 		return (EBUSY);
1622 	}
1623 	if (!VN_IS_DOOMED(vp)) {
1624 		counter_u64_add(recycles_free_count, 1);
1625 		vgonel(vp);
1626 	}
1627 	VOP_UNLOCK(vp);
1628 	vdropl(vp);
1629 	vn_finished_write(vnmp);
1630 	return (0);
1631 }
1632 
1633 /*
1634  * Allocate a new vnode.
1635  *
1636  * The operation never returns an error. Returning an error was disabled
1637  * in r145385 (dated 2005) with the following comment:
1638  *
1639  * XXX Not all VFS_VGET/ffs_vget callers check returns.
1640  *
1641  * Given the age of this commit (almost 15 years at the time of writing this
1642  * comment) restoring the ability to fail requires a significant audit of
1643  * all codepaths.
1644  *
1645  * The routine can try to free a vnode or stall for up to 1 second waiting for
1646  * vnlru to clear things up, but ultimately always performs a M_WAITOK allocation.
1647  */
1648 static u_long vn_alloc_cyclecount;
1649 
1650 static struct vnode * __noinline
1651 vn_alloc_hard(struct mount *mp)
1652 {
1653 	u_long rnumvnodes, rfreevnodes;
1654 
1655 	mtx_lock(&vnode_list_mtx);
1656 	rnumvnodes = atomic_load_long(&numvnodes);
1657 	if (rnumvnodes + 1 < desiredvnodes) {
1658 		vn_alloc_cyclecount = 0;
1659 		goto alloc;
1660 	}
1661 	rfreevnodes = vnlru_read_freevnodes();
1662 	if (vn_alloc_cyclecount++ >= rfreevnodes) {
1663 		vn_alloc_cyclecount = 0;
1664 		vstir = 1;
1665 	}
1666 	/*
1667 	 * Grow the vnode cache if it will not be above its target max
1668 	 * after growing.  Otherwise, if the free list is nonempty, try
1669 	 * to reclaim 1 item from it before growing the cache (possibly
1670 	 * above its target max if the reclamation failed or is delayed).
1671 	 * Otherwise, wait for some space.  In all cases, schedule
1672 	 * vnlru_proc() if we are getting short of space.  The watermarks
1673 	 * should be chosen so that we never wait or even reclaim from
1674 	 * the free list to below its target minimum.
1675 	 */
1676 	if (vnlru_free_locked(1) > 0)
1677 		goto alloc;
1678 	if (mp == NULL || (mp->mnt_kern_flag & MNTK_SUSPEND) == 0) {
1679 		/*
1680 		 * Wait for space for a new vnode.
1681 		 */
1682 		vnlru_kick();
1683 		msleep(&vnlruproc_sig, &vnode_list_mtx, PVFS, "vlruwk", hz);
1684 		if (atomic_load_long(&numvnodes) + 1 > desiredvnodes &&
1685 		    vnlru_read_freevnodes() > 1)
1686 			vnlru_free_locked(1);
1687 	}
1688 alloc:
1689 	rnumvnodes = atomic_fetchadd_long(&numvnodes, 1) + 1;
1690 	if (vnlru_under(rnumvnodes, vlowat))
1691 		vnlru_kick();
1692 	mtx_unlock(&vnode_list_mtx);
1693 	return (uma_zalloc_smr(vnode_zone, M_WAITOK));
1694 }
1695 
1696 static struct vnode *
1697 vn_alloc(struct mount *mp)
1698 {
1699 	u_long rnumvnodes;
1700 
1701 	if (__predict_false(vn_alloc_cyclecount != 0))
1702 		return (vn_alloc_hard(mp));
1703 	rnumvnodes = atomic_fetchadd_long(&numvnodes, 1) + 1;
1704 	if (__predict_false(vnlru_under_unlocked(rnumvnodes, vlowat))) {
1705 		atomic_subtract_long(&numvnodes, 1);
1706 		return (vn_alloc_hard(mp));
1707 	}
1708 
1709 	return (uma_zalloc_smr(vnode_zone, M_WAITOK));
1710 }
1711 
1712 static void
1713 vn_free(struct vnode *vp)
1714 {
1715 
1716 	atomic_subtract_long(&numvnodes, 1);
1717 	uma_zfree_smr(vnode_zone, vp);
1718 }
1719 
1720 /*
1721  * Return the next vnode from the free list.
1722  */
1723 int
1724 getnewvnode(const char *tag, struct mount *mp, struct vop_vector *vops,
1725     struct vnode **vpp)
1726 {
1727 	struct vnode *vp;
1728 	struct thread *td;
1729 	struct lock_object *lo;
1730 
1731 	CTR3(KTR_VFS, "%s: mp %p with tag %s", __func__, mp, tag);
1732 
1733 	KASSERT(vops->registered,
1734 	    ("%s: not registered vector op %p\n", __func__, vops));
1735 
1736 	td = curthread;
1737 	if (td->td_vp_reserved != NULL) {
1738 		vp = td->td_vp_reserved;
1739 		td->td_vp_reserved = NULL;
1740 	} else {
1741 		vp = vn_alloc(mp);
1742 	}
1743 	counter_u64_add(vnodes_created, 1);
1744 	/*
1745 	 * Locks are given the generic name "vnode" when created.
1746 	 * Follow the historic practice of using the filesystem
1747 	 * name when they allocated, e.g., "zfs", "ufs", "nfs, etc.
1748 	 *
1749 	 * Locks live in a witness group keyed on their name. Thus,
1750 	 * when a lock is renamed, it must also move from the witness
1751 	 * group of its old name to the witness group of its new name.
1752 	 *
1753 	 * The change only needs to be made when the vnode moves
1754 	 * from one filesystem type to another. We ensure that each
1755 	 * filesystem use a single static name pointer for its tag so
1756 	 * that we can compare pointers rather than doing a strcmp().
1757 	 */
1758 	lo = &vp->v_vnlock->lock_object;
1759 #ifdef WITNESS
1760 	if (lo->lo_name != tag) {
1761 #endif
1762 		lo->lo_name = tag;
1763 #ifdef WITNESS
1764 		WITNESS_DESTROY(lo);
1765 		WITNESS_INIT(lo, tag);
1766 	}
1767 #endif
1768 	/*
1769 	 * By default, don't allow shared locks unless filesystems opt-in.
1770 	 */
1771 	vp->v_vnlock->lock_object.lo_flags |= LK_NOSHARE;
1772 	/*
1773 	 * Finalize various vnode identity bits.
1774 	 */
1775 	KASSERT(vp->v_object == NULL, ("stale v_object %p", vp));
1776 	KASSERT(vp->v_lockf == NULL, ("stale v_lockf %p", vp));
1777 	KASSERT(vp->v_pollinfo == NULL, ("stale v_pollinfo %p", vp));
1778 	vp->v_type = VNON;
1779 	vp->v_op = vops;
1780 	vp->v_irflag = 0;
1781 	v_init_counters(vp);
1782 	vn_seqc_init(vp);
1783 	vp->v_bufobj.bo_ops = &buf_ops_bio;
1784 #ifdef DIAGNOSTIC
1785 	if (mp == NULL && vops != &dead_vnodeops)
1786 		printf("NULL mp in getnewvnode(9), tag %s\n", tag);
1787 #endif
1788 #ifdef MAC
1789 	mac_vnode_init(vp);
1790 	if (mp != NULL && (mp->mnt_flag & MNT_MULTILABEL) == 0)
1791 		mac_vnode_associate_singlelabel(mp, vp);
1792 #endif
1793 	if (mp != NULL) {
1794 		vp->v_bufobj.bo_bsize = mp->mnt_stat.f_iosize;
1795 		if ((mp->mnt_kern_flag & MNTK_NOKNOTE) != 0)
1796 			vp->v_vflag |= VV_NOKNOTE;
1797 	}
1798 
1799 	/*
1800 	 * For the filesystems which do not use vfs_hash_insert(),
1801 	 * still initialize v_hash to have vfs_hash_index() useful.
1802 	 * E.g., nullfs uses vfs_hash_index() on the lower vnode for
1803 	 * its own hashing.
1804 	 */
1805 	vp->v_hash = (uintptr_t)vp >> vnsz2log;
1806 
1807 	*vpp = vp;
1808 	return (0);
1809 }
1810 
1811 void
1812 getnewvnode_reserve(void)
1813 {
1814 	struct thread *td;
1815 
1816 	td = curthread;
1817 	MPASS(td->td_vp_reserved == NULL);
1818 	td->td_vp_reserved = vn_alloc(NULL);
1819 }
1820 
1821 void
1822 getnewvnode_drop_reserve(void)
1823 {
1824 	struct thread *td;
1825 
1826 	td = curthread;
1827 	if (td->td_vp_reserved != NULL) {
1828 		vn_free(td->td_vp_reserved);
1829 		td->td_vp_reserved = NULL;
1830 	}
1831 }
1832 
1833 static void __noinline
1834 freevnode(struct vnode *vp)
1835 {
1836 	struct bufobj *bo;
1837 
1838 	/*
1839 	 * The vnode has been marked for destruction, so free it.
1840 	 *
1841 	 * The vnode will be returned to the zone where it will
1842 	 * normally remain until it is needed for another vnode. We
1843 	 * need to cleanup (or verify that the cleanup has already
1844 	 * been done) any residual data left from its current use
1845 	 * so as not to contaminate the freshly allocated vnode.
1846 	 */
1847 	CTR2(KTR_VFS, "%s: destroying the vnode %p", __func__, vp);
1848 	/*
1849 	 * Paired with vgone.
1850 	 */
1851 	vn_seqc_write_end_free(vp);
1852 
1853 	bo = &vp->v_bufobj;
1854 	VNASSERT(vp->v_data == NULL, vp, ("cleaned vnode isn't"));
1855 	VNPASS(vp->v_holdcnt == VHOLD_NO_SMR, vp);
1856 	VNASSERT(vp->v_usecount == 0, vp, ("Non-zero use count"));
1857 	VNASSERT(vp->v_writecount == 0, vp, ("Non-zero write count"));
1858 	VNASSERT(bo->bo_numoutput == 0, vp, ("Clean vnode has pending I/O's"));
1859 	VNASSERT(bo->bo_clean.bv_cnt == 0, vp, ("cleanbufcnt not 0"));
1860 	VNASSERT(pctrie_is_empty(&bo->bo_clean.bv_root), vp,
1861 	    ("clean blk trie not empty"));
1862 	VNASSERT(bo->bo_dirty.bv_cnt == 0, vp, ("dirtybufcnt not 0"));
1863 	VNASSERT(pctrie_is_empty(&bo->bo_dirty.bv_root), vp,
1864 	    ("dirty blk trie not empty"));
1865 	VNASSERT(TAILQ_EMPTY(&vp->v_cache_dst), vp, ("vp has namecache dst"));
1866 	VNASSERT(LIST_EMPTY(&vp->v_cache_src), vp, ("vp has namecache src"));
1867 	VNASSERT(vp->v_cache_dd == NULL, vp, ("vp has namecache for .."));
1868 	VNASSERT(TAILQ_EMPTY(&vp->v_rl.rl_waiters), vp,
1869 	    ("Dangling rangelock waiters"));
1870 	VNASSERT((vp->v_iflag & (VI_DOINGINACT | VI_OWEINACT)) == 0, vp,
1871 	    ("Leaked inactivation"));
1872 	VI_UNLOCK(vp);
1873 #ifdef MAC
1874 	mac_vnode_destroy(vp);
1875 #endif
1876 	if (vp->v_pollinfo != NULL) {
1877 		destroy_vpollinfo(vp->v_pollinfo);
1878 		vp->v_pollinfo = NULL;
1879 	}
1880 	vp->v_mountedhere = NULL;
1881 	vp->v_unpcb = NULL;
1882 	vp->v_rdev = NULL;
1883 	vp->v_fifoinfo = NULL;
1884 	vp->v_iflag = 0;
1885 	vp->v_vflag = 0;
1886 	bo->bo_flag = 0;
1887 	vn_free(vp);
1888 }
1889 
1890 /*
1891  * Delete from old mount point vnode list, if on one.
1892  */
1893 static void
1894 delmntque(struct vnode *vp)
1895 {
1896 	struct mount *mp;
1897 
1898 	VNPASS((vp->v_mflag & VMP_LAZYLIST) == 0, vp);
1899 
1900 	mp = vp->v_mount;
1901 	if (mp == NULL)
1902 		return;
1903 	MNT_ILOCK(mp);
1904 	VI_LOCK(vp);
1905 	vp->v_mount = NULL;
1906 	VI_UNLOCK(vp);
1907 	VNASSERT(mp->mnt_nvnodelistsize > 0, vp,
1908 		("bad mount point vnode list size"));
1909 	TAILQ_REMOVE(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
1910 	mp->mnt_nvnodelistsize--;
1911 	MNT_REL(mp);
1912 	MNT_IUNLOCK(mp);
1913 }
1914 
1915 static void
1916 insmntque_stddtr(struct vnode *vp, void *dtr_arg)
1917 {
1918 
1919 	vp->v_data = NULL;
1920 	vp->v_op = &dead_vnodeops;
1921 	vgone(vp);
1922 	vput(vp);
1923 }
1924 
1925 /*
1926  * Insert into list of vnodes for the new mount point, if available.
1927  */
1928 int
1929 insmntque1(struct vnode *vp, struct mount *mp,
1930 	void (*dtr)(struct vnode *, void *), void *dtr_arg)
1931 {
1932 
1933 	KASSERT(vp->v_mount == NULL,
1934 		("insmntque: vnode already on per mount vnode list"));
1935 	VNASSERT(mp != NULL, vp, ("Don't call insmntque(foo, NULL)"));
1936 	ASSERT_VOP_ELOCKED(vp, "insmntque: non-locked vp");
1937 
1938 	/*
1939 	 * We acquire the vnode interlock early to ensure that the
1940 	 * vnode cannot be recycled by another process releasing a
1941 	 * holdcnt on it before we get it on both the vnode list
1942 	 * and the active vnode list. The mount mutex protects only
1943 	 * manipulation of the vnode list and the vnode freelist
1944 	 * mutex protects only manipulation of the active vnode list.
1945 	 * Hence the need to hold the vnode interlock throughout.
1946 	 */
1947 	MNT_ILOCK(mp);
1948 	VI_LOCK(vp);
1949 	if (((mp->mnt_kern_flag & MNTK_UNMOUNT) != 0 &&
1950 	    ((mp->mnt_kern_flag & MNTK_UNMOUNTF) != 0 ||
1951 	    mp->mnt_nvnodelistsize == 0)) &&
1952 	    (vp->v_vflag & VV_FORCEINSMQ) == 0) {
1953 		VI_UNLOCK(vp);
1954 		MNT_IUNLOCK(mp);
1955 		if (dtr != NULL)
1956 			dtr(vp, dtr_arg);
1957 		return (EBUSY);
1958 	}
1959 	vp->v_mount = mp;
1960 	MNT_REF(mp);
1961 	TAILQ_INSERT_TAIL(&mp->mnt_nvnodelist, vp, v_nmntvnodes);
1962 	VNASSERT(mp->mnt_nvnodelistsize >= 0, vp,
1963 		("neg mount point vnode list size"));
1964 	mp->mnt_nvnodelistsize++;
1965 	VI_UNLOCK(vp);
1966 	MNT_IUNLOCK(mp);
1967 	return (0);
1968 }
1969 
1970 int
1971 insmntque(struct vnode *vp, struct mount *mp)
1972 {
1973 
1974 	return (insmntque1(vp, mp, insmntque_stddtr, NULL));
1975 }
1976 
1977 /*
1978  * Flush out and invalidate all buffers associated with a bufobj
1979  * Called with the underlying object locked.
1980  */
1981 int
1982 bufobj_invalbuf(struct bufobj *bo, int flags, int slpflag, int slptimeo)
1983 {
1984 	int error;
1985 
1986 	BO_LOCK(bo);
1987 	if (flags & V_SAVE) {
1988 		error = bufobj_wwait(bo, slpflag, slptimeo);
1989 		if (error) {
1990 			BO_UNLOCK(bo);
1991 			return (error);
1992 		}
1993 		if (bo->bo_dirty.bv_cnt > 0) {
1994 			BO_UNLOCK(bo);
1995 			do {
1996 				error = BO_SYNC(bo, MNT_WAIT);
1997 			} while (error == ERELOOKUP);
1998 			if (error != 0)
1999 				return (error);
2000 			/*
2001 			 * XXX We could save a lock/unlock if this was only
2002 			 * enabled under INVARIANTS
2003 			 */
2004 			BO_LOCK(bo);
2005 			if (bo->bo_numoutput > 0 || bo->bo_dirty.bv_cnt > 0)
2006 				panic("vinvalbuf: dirty bufs");
2007 		}
2008 	}
2009 	/*
2010 	 * If you alter this loop please notice that interlock is dropped and
2011 	 * reacquired in flushbuflist.  Special care is needed to ensure that
2012 	 * no race conditions occur from this.
2013 	 */
2014 	do {
2015 		error = flushbuflist(&bo->bo_clean,
2016 		    flags, bo, slpflag, slptimeo);
2017 		if (error == 0 && !(flags & V_CLEANONLY))
2018 			error = flushbuflist(&bo->bo_dirty,
2019 			    flags, bo, slpflag, slptimeo);
2020 		if (error != 0 && error != EAGAIN) {
2021 			BO_UNLOCK(bo);
2022 			return (error);
2023 		}
2024 	} while (error != 0);
2025 
2026 	/*
2027 	 * Wait for I/O to complete.  XXX needs cleaning up.  The vnode can
2028 	 * have write I/O in-progress but if there is a VM object then the
2029 	 * VM object can also have read-I/O in-progress.
2030 	 */
2031 	do {
2032 		bufobj_wwait(bo, 0, 0);
2033 		if ((flags & V_VMIO) == 0 && bo->bo_object != NULL) {
2034 			BO_UNLOCK(bo);
2035 			vm_object_pip_wait_unlocked(bo->bo_object, "bovlbx");
2036 			BO_LOCK(bo);
2037 		}
2038 	} while (bo->bo_numoutput > 0);
2039 	BO_UNLOCK(bo);
2040 
2041 	/*
2042 	 * Destroy the copy in the VM cache, too.
2043 	 */
2044 	if (bo->bo_object != NULL &&
2045 	    (flags & (V_ALT | V_NORMAL | V_CLEANONLY | V_VMIO)) == 0) {
2046 		VM_OBJECT_WLOCK(bo->bo_object);
2047 		vm_object_page_remove(bo->bo_object, 0, 0, (flags & V_SAVE) ?
2048 		    OBJPR_CLEANONLY : 0);
2049 		VM_OBJECT_WUNLOCK(bo->bo_object);
2050 	}
2051 
2052 #ifdef INVARIANTS
2053 	BO_LOCK(bo);
2054 	if ((flags & (V_ALT | V_NORMAL | V_CLEANONLY | V_VMIO |
2055 	    V_ALLOWCLEAN)) == 0 && (bo->bo_dirty.bv_cnt > 0 ||
2056 	    bo->bo_clean.bv_cnt > 0))
2057 		panic("vinvalbuf: flush failed");
2058 	if ((flags & (V_ALT | V_NORMAL | V_CLEANONLY | V_VMIO)) == 0 &&
2059 	    bo->bo_dirty.bv_cnt > 0)
2060 		panic("vinvalbuf: flush dirty failed");
2061 	BO_UNLOCK(bo);
2062 #endif
2063 	return (0);
2064 }
2065 
2066 /*
2067  * Flush out and invalidate all buffers associated with a vnode.
2068  * Called with the underlying object locked.
2069  */
2070 int
2071 vinvalbuf(struct vnode *vp, int flags, int slpflag, int slptimeo)
2072 {
2073 
2074 	CTR3(KTR_VFS, "%s: vp %p with flags %d", __func__, vp, flags);
2075 	ASSERT_VOP_LOCKED(vp, "vinvalbuf");
2076 	if (vp->v_object != NULL && vp->v_object->handle != vp)
2077 		return (0);
2078 	return (bufobj_invalbuf(&vp->v_bufobj, flags, slpflag, slptimeo));
2079 }
2080 
2081 /*
2082  * Flush out buffers on the specified list.
2083  *
2084  */
2085 static int
2086 flushbuflist(struct bufv *bufv, int flags, struct bufobj *bo, int slpflag,
2087     int slptimeo)
2088 {
2089 	struct buf *bp, *nbp;
2090 	int retval, error;
2091 	daddr_t lblkno;
2092 	b_xflags_t xflags;
2093 
2094 	ASSERT_BO_WLOCKED(bo);
2095 
2096 	retval = 0;
2097 	TAILQ_FOREACH_SAFE(bp, &bufv->bv_hd, b_bobufs, nbp) {
2098 		/*
2099 		 * If we are flushing both V_NORMAL and V_ALT buffers then
2100 		 * do not skip any buffers. If we are flushing only V_NORMAL
2101 		 * buffers then skip buffers marked as BX_ALTDATA. If we are
2102 		 * flushing only V_ALT buffers then skip buffers not marked
2103 		 * as BX_ALTDATA.
2104 		 */
2105 		if (((flags & (V_NORMAL | V_ALT)) != (V_NORMAL | V_ALT)) &&
2106 		   (((flags & V_NORMAL) && (bp->b_xflags & BX_ALTDATA) != 0) ||
2107 		    ((flags & V_ALT) && (bp->b_xflags & BX_ALTDATA) == 0))) {
2108 			continue;
2109 		}
2110 		if (nbp != NULL) {
2111 			lblkno = nbp->b_lblkno;
2112 			xflags = nbp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN);
2113 		}
2114 		retval = EAGAIN;
2115 		error = BUF_TIMELOCK(bp,
2116 		    LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK, BO_LOCKPTR(bo),
2117 		    "flushbuf", slpflag, slptimeo);
2118 		if (error) {
2119 			BO_LOCK(bo);
2120 			return (error != ENOLCK ? error : EAGAIN);
2121 		}
2122 		KASSERT(bp->b_bufobj == bo,
2123 		    ("bp %p wrong b_bufobj %p should be %p",
2124 		    bp, bp->b_bufobj, bo));
2125 		/*
2126 		 * XXX Since there are no node locks for NFS, I
2127 		 * believe there is a slight chance that a delayed
2128 		 * write will occur while sleeping just above, so
2129 		 * check for it.
2130 		 */
2131 		if (((bp->b_flags & (B_DELWRI | B_INVAL)) == B_DELWRI) &&
2132 		    (flags & V_SAVE)) {
2133 			bremfree(bp);
2134 			bp->b_flags |= B_ASYNC;
2135 			bwrite(bp);
2136 			BO_LOCK(bo);
2137 			return (EAGAIN);	/* XXX: why not loop ? */
2138 		}
2139 		bremfree(bp);
2140 		bp->b_flags |= (B_INVAL | B_RELBUF);
2141 		bp->b_flags &= ~B_ASYNC;
2142 		brelse(bp);
2143 		BO_LOCK(bo);
2144 		if (nbp == NULL)
2145 			break;
2146 		nbp = gbincore(bo, lblkno);
2147 		if (nbp == NULL || (nbp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN))
2148 		    != xflags)
2149 			break;			/* nbp invalid */
2150 	}
2151 	return (retval);
2152 }
2153 
2154 int
2155 bnoreuselist(struct bufv *bufv, struct bufobj *bo, daddr_t startn, daddr_t endn)
2156 {
2157 	struct buf *bp;
2158 	int error;
2159 	daddr_t lblkno;
2160 
2161 	ASSERT_BO_LOCKED(bo);
2162 
2163 	for (lblkno = startn;;) {
2164 again:
2165 		bp = BUF_PCTRIE_LOOKUP_GE(&bufv->bv_root, lblkno);
2166 		if (bp == NULL || bp->b_lblkno >= endn ||
2167 		    bp->b_lblkno < startn)
2168 			break;
2169 		error = BUF_TIMELOCK(bp, LK_EXCLUSIVE | LK_SLEEPFAIL |
2170 		    LK_INTERLOCK, BO_LOCKPTR(bo), "brlsfl", 0, 0);
2171 		if (error != 0) {
2172 			BO_RLOCK(bo);
2173 			if (error == ENOLCK)
2174 				goto again;
2175 			return (error);
2176 		}
2177 		KASSERT(bp->b_bufobj == bo,
2178 		    ("bp %p wrong b_bufobj %p should be %p",
2179 		    bp, bp->b_bufobj, bo));
2180 		lblkno = bp->b_lblkno + 1;
2181 		if ((bp->b_flags & B_MANAGED) == 0)
2182 			bremfree(bp);
2183 		bp->b_flags |= B_RELBUF;
2184 		/*
2185 		 * In the VMIO case, use the B_NOREUSE flag to hint that the
2186 		 * pages backing each buffer in the range are unlikely to be
2187 		 * reused.  Dirty buffers will have the hint applied once
2188 		 * they've been written.
2189 		 */
2190 		if ((bp->b_flags & B_VMIO) != 0)
2191 			bp->b_flags |= B_NOREUSE;
2192 		brelse(bp);
2193 		BO_RLOCK(bo);
2194 	}
2195 	return (0);
2196 }
2197 
2198 /*
2199  * Truncate a file's buffer and pages to a specified length.  This
2200  * is in lieu of the old vinvalbuf mechanism, which performed unneeded
2201  * sync activity.
2202  */
2203 int
2204 vtruncbuf(struct vnode *vp, off_t length, int blksize)
2205 {
2206 	struct buf *bp, *nbp;
2207 	struct bufobj *bo;
2208 	daddr_t startlbn;
2209 
2210 	CTR4(KTR_VFS, "%s: vp %p with block %d:%ju", __func__,
2211 	    vp, blksize, (uintmax_t)length);
2212 
2213 	/*
2214 	 * Round up to the *next* lbn.
2215 	 */
2216 	startlbn = howmany(length, blksize);
2217 
2218 	ASSERT_VOP_LOCKED(vp, "vtruncbuf");
2219 
2220 	bo = &vp->v_bufobj;
2221 restart_unlocked:
2222 	BO_LOCK(bo);
2223 
2224 	while (v_inval_buf_range_locked(vp, bo, startlbn, INT64_MAX) == EAGAIN)
2225 		;
2226 
2227 	if (length > 0) {
2228 restartsync:
2229 		TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
2230 			if (bp->b_lblkno > 0)
2231 				continue;
2232 			/*
2233 			 * Since we hold the vnode lock this should only
2234 			 * fail if we're racing with the buf daemon.
2235 			 */
2236 			if (BUF_LOCK(bp,
2237 			    LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
2238 			    BO_LOCKPTR(bo)) == ENOLCK)
2239 				goto restart_unlocked;
2240 
2241 			VNASSERT((bp->b_flags & B_DELWRI), vp,
2242 			    ("buf(%p) on dirty queue without DELWRI", bp));
2243 
2244 			bremfree(bp);
2245 			bawrite(bp);
2246 			BO_LOCK(bo);
2247 			goto restartsync;
2248 		}
2249 	}
2250 
2251 	bufobj_wwait(bo, 0, 0);
2252 	BO_UNLOCK(bo);
2253 	vnode_pager_setsize(vp, length);
2254 
2255 	return (0);
2256 }
2257 
2258 /*
2259  * Invalidate the cached pages of a file's buffer within the range of block
2260  * numbers [startlbn, endlbn).
2261  */
2262 void
2263 v_inval_buf_range(struct vnode *vp, daddr_t startlbn, daddr_t endlbn,
2264     int blksize)
2265 {
2266 	struct bufobj *bo;
2267 	off_t start, end;
2268 
2269 	ASSERT_VOP_LOCKED(vp, "v_inval_buf_range");
2270 
2271 	start = blksize * startlbn;
2272 	end = blksize * endlbn;
2273 
2274 	bo = &vp->v_bufobj;
2275 	BO_LOCK(bo);
2276 	MPASS(blksize == bo->bo_bsize);
2277 
2278 	while (v_inval_buf_range_locked(vp, bo, startlbn, endlbn) == EAGAIN)
2279 		;
2280 
2281 	BO_UNLOCK(bo);
2282 	vn_pages_remove(vp, OFF_TO_IDX(start), OFF_TO_IDX(end + PAGE_SIZE - 1));
2283 }
2284 
2285 static int
2286 v_inval_buf_range_locked(struct vnode *vp, struct bufobj *bo,
2287     daddr_t startlbn, daddr_t endlbn)
2288 {
2289 	struct buf *bp, *nbp;
2290 	bool anyfreed;
2291 
2292 	ASSERT_VOP_LOCKED(vp, "v_inval_buf_range_locked");
2293 	ASSERT_BO_LOCKED(bo);
2294 
2295 	do {
2296 		anyfreed = false;
2297 		TAILQ_FOREACH_SAFE(bp, &bo->bo_clean.bv_hd, b_bobufs, nbp) {
2298 			if (bp->b_lblkno < startlbn || bp->b_lblkno >= endlbn)
2299 				continue;
2300 			if (BUF_LOCK(bp,
2301 			    LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
2302 			    BO_LOCKPTR(bo)) == ENOLCK) {
2303 				BO_LOCK(bo);
2304 				return (EAGAIN);
2305 			}
2306 
2307 			bremfree(bp);
2308 			bp->b_flags |= B_INVAL | B_RELBUF;
2309 			bp->b_flags &= ~B_ASYNC;
2310 			brelse(bp);
2311 			anyfreed = true;
2312 
2313 			BO_LOCK(bo);
2314 			if (nbp != NULL &&
2315 			    (((nbp->b_xflags & BX_VNCLEAN) == 0) ||
2316 			    nbp->b_vp != vp ||
2317 			    (nbp->b_flags & B_DELWRI) != 0))
2318 				return (EAGAIN);
2319 		}
2320 
2321 		TAILQ_FOREACH_SAFE(bp, &bo->bo_dirty.bv_hd, b_bobufs, nbp) {
2322 			if (bp->b_lblkno < startlbn || bp->b_lblkno >= endlbn)
2323 				continue;
2324 			if (BUF_LOCK(bp,
2325 			    LK_EXCLUSIVE | LK_SLEEPFAIL | LK_INTERLOCK,
2326 			    BO_LOCKPTR(bo)) == ENOLCK) {
2327 				BO_LOCK(bo);
2328 				return (EAGAIN);
2329 			}
2330 			bremfree(bp);
2331 			bp->b_flags |= B_INVAL | B_RELBUF;
2332 			bp->b_flags &= ~B_ASYNC;
2333 			brelse(bp);
2334 			anyfreed = true;
2335 
2336 			BO_LOCK(bo);
2337 			if (nbp != NULL &&
2338 			    (((nbp->b_xflags & BX_VNDIRTY) == 0) ||
2339 			    (nbp->b_vp != vp) ||
2340 			    (nbp->b_flags & B_DELWRI) == 0))
2341 				return (EAGAIN);
2342 		}
2343 	} while (anyfreed);
2344 	return (0);
2345 }
2346 
2347 static void
2348 buf_vlist_remove(struct buf *bp)
2349 {
2350 	struct bufv *bv;
2351 	b_xflags_t flags;
2352 
2353 	flags = bp->b_xflags;
2354 
2355 	KASSERT(bp->b_bufobj != NULL, ("No b_bufobj %p", bp));
2356 	ASSERT_BO_WLOCKED(bp->b_bufobj);
2357 	KASSERT((flags & (BX_VNDIRTY | BX_VNCLEAN)) != 0 &&
2358 	    (flags & (BX_VNDIRTY | BX_VNCLEAN)) != (BX_VNDIRTY | BX_VNCLEAN),
2359 	    ("%s: buffer %p has invalid queue state", __func__, bp));
2360 
2361 	if ((flags & BX_VNDIRTY) != 0)
2362 		bv = &bp->b_bufobj->bo_dirty;
2363 	else
2364 		bv = &bp->b_bufobj->bo_clean;
2365 	BUF_PCTRIE_REMOVE(&bv->bv_root, bp->b_lblkno);
2366 	TAILQ_REMOVE(&bv->bv_hd, bp, b_bobufs);
2367 	bv->bv_cnt--;
2368 	bp->b_xflags &= ~(BX_VNDIRTY | BX_VNCLEAN);
2369 }
2370 
2371 /*
2372  * Add the buffer to the sorted clean or dirty block list.
2373  *
2374  * NOTE: xflags is passed as a constant, optimizing this inline function!
2375  */
2376 static void
2377 buf_vlist_add(struct buf *bp, struct bufobj *bo, b_xflags_t xflags)
2378 {
2379 	struct bufv *bv;
2380 	struct buf *n;
2381 	int error;
2382 
2383 	ASSERT_BO_WLOCKED(bo);
2384 	KASSERT((bo->bo_flag & BO_NOBUFS) == 0,
2385 	    ("buf_vlist_add: bo %p does not allow bufs", bo));
2386 	KASSERT((xflags & BX_VNDIRTY) == 0 || (bo->bo_flag & BO_DEAD) == 0,
2387 	    ("dead bo %p", bo));
2388 	KASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0,
2389 	    ("buf_vlist_add: Buf %p has existing xflags %d", bp, bp->b_xflags));
2390 	bp->b_xflags |= xflags;
2391 	if (xflags & BX_VNDIRTY)
2392 		bv = &bo->bo_dirty;
2393 	else
2394 		bv = &bo->bo_clean;
2395 
2396 	/*
2397 	 * Keep the list ordered.  Optimize empty list insertion.  Assume
2398 	 * we tend to grow at the tail so lookup_le should usually be cheaper
2399 	 * than _ge.
2400 	 */
2401 	if (bv->bv_cnt == 0 ||
2402 	    bp->b_lblkno > TAILQ_LAST(&bv->bv_hd, buflists)->b_lblkno)
2403 		TAILQ_INSERT_TAIL(&bv->bv_hd, bp, b_bobufs);
2404 	else if ((n = BUF_PCTRIE_LOOKUP_LE(&bv->bv_root, bp->b_lblkno)) == NULL)
2405 		TAILQ_INSERT_HEAD(&bv->bv_hd, bp, b_bobufs);
2406 	else
2407 		TAILQ_INSERT_AFTER(&bv->bv_hd, n, bp, b_bobufs);
2408 	error = BUF_PCTRIE_INSERT(&bv->bv_root, bp);
2409 	if (error)
2410 		panic("buf_vlist_add:  Preallocated nodes insufficient.");
2411 	bv->bv_cnt++;
2412 }
2413 
2414 /*
2415  * Look up a buffer using the buffer tries.
2416  */
2417 struct buf *
2418 gbincore(struct bufobj *bo, daddr_t lblkno)
2419 {
2420 	struct buf *bp;
2421 
2422 	ASSERT_BO_LOCKED(bo);
2423 	bp = BUF_PCTRIE_LOOKUP(&bo->bo_clean.bv_root, lblkno);
2424 	if (bp != NULL)
2425 		return (bp);
2426 	return (BUF_PCTRIE_LOOKUP(&bo->bo_dirty.bv_root, lblkno));
2427 }
2428 
2429 /*
2430  * Look up a buf using the buffer tries, without the bufobj lock.  This relies
2431  * on SMR for safe lookup, and bufs being in a no-free zone to provide type
2432  * stability of the result.  Like other lockless lookups, the found buf may
2433  * already be invalid by the time this function returns.
2434  */
2435 struct buf *
2436 gbincore_unlocked(struct bufobj *bo, daddr_t lblkno)
2437 {
2438 	struct buf *bp;
2439 
2440 	ASSERT_BO_UNLOCKED(bo);
2441 	bp = BUF_PCTRIE_LOOKUP_UNLOCKED(&bo->bo_clean.bv_root, lblkno);
2442 	if (bp != NULL)
2443 		return (bp);
2444 	return (BUF_PCTRIE_LOOKUP_UNLOCKED(&bo->bo_dirty.bv_root, lblkno));
2445 }
2446 
2447 /*
2448  * Associate a buffer with a vnode.
2449  */
2450 void
2451 bgetvp(struct vnode *vp, struct buf *bp)
2452 {
2453 	struct bufobj *bo;
2454 
2455 	bo = &vp->v_bufobj;
2456 	ASSERT_BO_WLOCKED(bo);
2457 	VNASSERT(bp->b_vp == NULL, bp->b_vp, ("bgetvp: not free"));
2458 
2459 	CTR3(KTR_BUF, "bgetvp(%p) vp %p flags %X", bp, vp, bp->b_flags);
2460 	VNASSERT((bp->b_xflags & (BX_VNDIRTY|BX_VNCLEAN)) == 0, vp,
2461 	    ("bgetvp: bp already attached! %p", bp));
2462 
2463 	vhold(vp);
2464 	bp->b_vp = vp;
2465 	bp->b_bufobj = bo;
2466 	/*
2467 	 * Insert onto list for new vnode.
2468 	 */
2469 	buf_vlist_add(bp, bo, BX_VNCLEAN);
2470 }
2471 
2472 /*
2473  * Disassociate a buffer from a vnode.
2474  */
2475 void
2476 brelvp(struct buf *bp)
2477 {
2478 	struct bufobj *bo;
2479 	struct vnode *vp;
2480 
2481 	CTR3(KTR_BUF, "brelvp(%p) vp %p flags %X", bp, bp->b_vp, bp->b_flags);
2482 	KASSERT(bp->b_vp != NULL, ("brelvp: NULL"));
2483 
2484 	/*
2485 	 * Delete from old vnode list, if on one.
2486 	 */
2487 	vp = bp->b_vp;		/* XXX */
2488 	bo = bp->b_bufobj;
2489 	BO_LOCK(bo);
2490 	buf_vlist_remove(bp);
2491 	if ((bo->bo_flag & BO_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
2492 		bo->bo_flag &= ~BO_ONWORKLST;
2493 		mtx_lock(&sync_mtx);
2494 		LIST_REMOVE(bo, bo_synclist);
2495 		syncer_worklist_len--;
2496 		mtx_unlock(&sync_mtx);
2497 	}
2498 	bp->b_vp = NULL;
2499 	bp->b_bufobj = NULL;
2500 	BO_UNLOCK(bo);
2501 	vdrop(vp);
2502 }
2503 
2504 /*
2505  * Add an item to the syncer work queue.
2506  */
2507 static void
2508 vn_syncer_add_to_worklist(struct bufobj *bo, int delay)
2509 {
2510 	int slot;
2511 
2512 	ASSERT_BO_WLOCKED(bo);
2513 
2514 	mtx_lock(&sync_mtx);
2515 	if (bo->bo_flag & BO_ONWORKLST)
2516 		LIST_REMOVE(bo, bo_synclist);
2517 	else {
2518 		bo->bo_flag |= BO_ONWORKLST;
2519 		syncer_worklist_len++;
2520 	}
2521 
2522 	if (delay > syncer_maxdelay - 2)
2523 		delay = syncer_maxdelay - 2;
2524 	slot = (syncer_delayno + delay) & syncer_mask;
2525 
2526 	LIST_INSERT_HEAD(&syncer_workitem_pending[slot], bo, bo_synclist);
2527 	mtx_unlock(&sync_mtx);
2528 }
2529 
2530 static int
2531 sysctl_vfs_worklist_len(SYSCTL_HANDLER_ARGS)
2532 {
2533 	int error, len;
2534 
2535 	mtx_lock(&sync_mtx);
2536 	len = syncer_worklist_len - sync_vnode_count;
2537 	mtx_unlock(&sync_mtx);
2538 	error = SYSCTL_OUT(req, &len, sizeof(len));
2539 	return (error);
2540 }
2541 
2542 SYSCTL_PROC(_vfs, OID_AUTO, worklist_len,
2543     CTLTYPE_INT | CTLFLAG_MPSAFE| CTLFLAG_RD, NULL, 0,
2544     sysctl_vfs_worklist_len, "I", "Syncer thread worklist length");
2545 
2546 static struct proc *updateproc;
2547 static void sched_sync(void);
2548 static struct kproc_desc up_kp = {
2549 	"syncer",
2550 	sched_sync,
2551 	&updateproc
2552 };
2553 SYSINIT(syncer, SI_SUB_KTHREAD_UPDATE, SI_ORDER_FIRST, kproc_start, &up_kp);
2554 
2555 static int
2556 sync_vnode(struct synclist *slp, struct bufobj **bo, struct thread *td)
2557 {
2558 	struct vnode *vp;
2559 	struct mount *mp;
2560 
2561 	*bo = LIST_FIRST(slp);
2562 	if (*bo == NULL)
2563 		return (0);
2564 	vp = bo2vnode(*bo);
2565 	if (VOP_ISLOCKED(vp) != 0 || VI_TRYLOCK(vp) == 0)
2566 		return (1);
2567 	/*
2568 	 * We use vhold in case the vnode does not
2569 	 * successfully sync.  vhold prevents the vnode from
2570 	 * going away when we unlock the sync_mtx so that
2571 	 * we can acquire the vnode interlock.
2572 	 */
2573 	vholdl(vp);
2574 	mtx_unlock(&sync_mtx);
2575 	VI_UNLOCK(vp);
2576 	if (vn_start_write(vp, &mp, V_NOWAIT) != 0) {
2577 		vdrop(vp);
2578 		mtx_lock(&sync_mtx);
2579 		return (*bo == LIST_FIRST(slp));
2580 	}
2581 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
2582 	(void) VOP_FSYNC(vp, MNT_LAZY, td);
2583 	VOP_UNLOCK(vp);
2584 	vn_finished_write(mp);
2585 	BO_LOCK(*bo);
2586 	if (((*bo)->bo_flag & BO_ONWORKLST) != 0) {
2587 		/*
2588 		 * Put us back on the worklist.  The worklist
2589 		 * routine will remove us from our current
2590 		 * position and then add us back in at a later
2591 		 * position.
2592 		 */
2593 		vn_syncer_add_to_worklist(*bo, syncdelay);
2594 	}
2595 	BO_UNLOCK(*bo);
2596 	vdrop(vp);
2597 	mtx_lock(&sync_mtx);
2598 	return (0);
2599 }
2600 
2601 static int first_printf = 1;
2602 
2603 /*
2604  * System filesystem synchronizer daemon.
2605  */
2606 static void
2607 sched_sync(void)
2608 {
2609 	struct synclist *next, *slp;
2610 	struct bufobj *bo;
2611 	long starttime;
2612 	struct thread *td = curthread;
2613 	int last_work_seen;
2614 	int net_worklist_len;
2615 	int syncer_final_iter;
2616 	int error;
2617 
2618 	last_work_seen = 0;
2619 	syncer_final_iter = 0;
2620 	syncer_state = SYNCER_RUNNING;
2621 	starttime = time_uptime;
2622 	td->td_pflags |= TDP_NORUNNINGBUF;
2623 
2624 	EVENTHANDLER_REGISTER(shutdown_pre_sync, syncer_shutdown, td->td_proc,
2625 	    SHUTDOWN_PRI_LAST);
2626 
2627 	mtx_lock(&sync_mtx);
2628 	for (;;) {
2629 		if (syncer_state == SYNCER_FINAL_DELAY &&
2630 		    syncer_final_iter == 0) {
2631 			mtx_unlock(&sync_mtx);
2632 			kproc_suspend_check(td->td_proc);
2633 			mtx_lock(&sync_mtx);
2634 		}
2635 		net_worklist_len = syncer_worklist_len - sync_vnode_count;
2636 		if (syncer_state != SYNCER_RUNNING &&
2637 		    starttime != time_uptime) {
2638 			if (first_printf) {
2639 				printf("\nSyncing disks, vnodes remaining... ");
2640 				first_printf = 0;
2641 			}
2642 			printf("%d ", net_worklist_len);
2643 		}
2644 		starttime = time_uptime;
2645 
2646 		/*
2647 		 * Push files whose dirty time has expired.  Be careful
2648 		 * of interrupt race on slp queue.
2649 		 *
2650 		 * Skip over empty worklist slots when shutting down.
2651 		 */
2652 		do {
2653 			slp = &syncer_workitem_pending[syncer_delayno];
2654 			syncer_delayno += 1;
2655 			if (syncer_delayno == syncer_maxdelay)
2656 				syncer_delayno = 0;
2657 			next = &syncer_workitem_pending[syncer_delayno];
2658 			/*
2659 			 * If the worklist has wrapped since the
2660 			 * it was emptied of all but syncer vnodes,
2661 			 * switch to the FINAL_DELAY state and run
2662 			 * for one more second.
2663 			 */
2664 			if (syncer_state == SYNCER_SHUTTING_DOWN &&
2665 			    net_worklist_len == 0 &&
2666 			    last_work_seen == syncer_delayno) {
2667 				syncer_state = SYNCER_FINAL_DELAY;
2668 				syncer_final_iter = SYNCER_SHUTDOWN_SPEEDUP;
2669 			}
2670 		} while (syncer_state != SYNCER_RUNNING && LIST_EMPTY(slp) &&
2671 		    syncer_worklist_len > 0);
2672 
2673 		/*
2674 		 * Keep track of the last time there was anything
2675 		 * on the worklist other than syncer vnodes.
2676 		 * Return to the SHUTTING_DOWN state if any
2677 		 * new work appears.
2678 		 */
2679 		if (net_worklist_len > 0 || syncer_state == SYNCER_RUNNING)
2680 			last_work_seen = syncer_delayno;
2681 		if (net_worklist_len > 0 && syncer_state == SYNCER_FINAL_DELAY)
2682 			syncer_state = SYNCER_SHUTTING_DOWN;
2683 		while (!LIST_EMPTY(slp)) {
2684 			error = sync_vnode(slp, &bo, td);
2685 			if (error == 1) {
2686 				LIST_REMOVE(bo, bo_synclist);
2687 				LIST_INSERT_HEAD(next, bo, bo_synclist);
2688 				continue;
2689 			}
2690 
2691 			if (first_printf == 0) {
2692 				/*
2693 				 * Drop the sync mutex, because some watchdog
2694 				 * drivers need to sleep while patting
2695 				 */
2696 				mtx_unlock(&sync_mtx);
2697 				wdog_kern_pat(WD_LASTVAL);
2698 				mtx_lock(&sync_mtx);
2699 			}
2700 		}
2701 		if (syncer_state == SYNCER_FINAL_DELAY && syncer_final_iter > 0)
2702 			syncer_final_iter--;
2703 		/*
2704 		 * The variable rushjob allows the kernel to speed up the
2705 		 * processing of the filesystem syncer process. A rushjob
2706 		 * value of N tells the filesystem syncer to process the next
2707 		 * N seconds worth of work on its queue ASAP. Currently rushjob
2708 		 * is used by the soft update code to speed up the filesystem
2709 		 * syncer process when the incore state is getting so far
2710 		 * ahead of the disk that the kernel memory pool is being
2711 		 * threatened with exhaustion.
2712 		 */
2713 		if (rushjob > 0) {
2714 			rushjob -= 1;
2715 			continue;
2716 		}
2717 		/*
2718 		 * Just sleep for a short period of time between
2719 		 * iterations when shutting down to allow some I/O
2720 		 * to happen.
2721 		 *
2722 		 * If it has taken us less than a second to process the
2723 		 * current work, then wait. Otherwise start right over
2724 		 * again. We can still lose time if any single round
2725 		 * takes more than two seconds, but it does not really
2726 		 * matter as we are just trying to generally pace the
2727 		 * filesystem activity.
2728 		 */
2729 		if (syncer_state != SYNCER_RUNNING ||
2730 		    time_uptime == starttime) {
2731 			thread_lock(td);
2732 			sched_prio(td, PPAUSE);
2733 			thread_unlock(td);
2734 		}
2735 		if (syncer_state != SYNCER_RUNNING)
2736 			cv_timedwait(&sync_wakeup, &sync_mtx,
2737 			    hz / SYNCER_SHUTDOWN_SPEEDUP);
2738 		else if (time_uptime == starttime)
2739 			cv_timedwait(&sync_wakeup, &sync_mtx, hz);
2740 	}
2741 }
2742 
2743 /*
2744  * Request the syncer daemon to speed up its work.
2745  * We never push it to speed up more than half of its
2746  * normal turn time, otherwise it could take over the cpu.
2747  */
2748 int
2749 speedup_syncer(void)
2750 {
2751 	int ret = 0;
2752 
2753 	mtx_lock(&sync_mtx);
2754 	if (rushjob < syncdelay / 2) {
2755 		rushjob += 1;
2756 		stat_rush_requests += 1;
2757 		ret = 1;
2758 	}
2759 	mtx_unlock(&sync_mtx);
2760 	cv_broadcast(&sync_wakeup);
2761 	return (ret);
2762 }
2763 
2764 /*
2765  * Tell the syncer to speed up its work and run though its work
2766  * list several times, then tell it to shut down.
2767  */
2768 static void
2769 syncer_shutdown(void *arg, int howto)
2770 {
2771 
2772 	if (howto & RB_NOSYNC)
2773 		return;
2774 	mtx_lock(&sync_mtx);
2775 	syncer_state = SYNCER_SHUTTING_DOWN;
2776 	rushjob = 0;
2777 	mtx_unlock(&sync_mtx);
2778 	cv_broadcast(&sync_wakeup);
2779 	kproc_shutdown(arg, howto);
2780 }
2781 
2782 void
2783 syncer_suspend(void)
2784 {
2785 
2786 	syncer_shutdown(updateproc, 0);
2787 }
2788 
2789 void
2790 syncer_resume(void)
2791 {
2792 
2793 	mtx_lock(&sync_mtx);
2794 	first_printf = 1;
2795 	syncer_state = SYNCER_RUNNING;
2796 	mtx_unlock(&sync_mtx);
2797 	cv_broadcast(&sync_wakeup);
2798 	kproc_resume(updateproc);
2799 }
2800 
2801 /*
2802  * Move the buffer between the clean and dirty lists of its vnode.
2803  */
2804 void
2805 reassignbuf(struct buf *bp)
2806 {
2807 	struct vnode *vp;
2808 	struct bufobj *bo;
2809 	int delay;
2810 #ifdef INVARIANTS
2811 	struct bufv *bv;
2812 #endif
2813 
2814 	vp = bp->b_vp;
2815 	bo = bp->b_bufobj;
2816 
2817 	KASSERT((bp->b_flags & B_PAGING) == 0,
2818 	    ("%s: cannot reassign paging buffer %p", __func__, bp));
2819 
2820 	CTR3(KTR_BUF, "reassignbuf(%p) vp %p flags %X",
2821 	    bp, bp->b_vp, bp->b_flags);
2822 
2823 	BO_LOCK(bo);
2824 	buf_vlist_remove(bp);
2825 
2826 	/*
2827 	 * If dirty, put on list of dirty buffers; otherwise insert onto list
2828 	 * of clean buffers.
2829 	 */
2830 	if (bp->b_flags & B_DELWRI) {
2831 		if ((bo->bo_flag & BO_ONWORKLST) == 0) {
2832 			switch (vp->v_type) {
2833 			case VDIR:
2834 				delay = dirdelay;
2835 				break;
2836 			case VCHR:
2837 				delay = metadelay;
2838 				break;
2839 			default:
2840 				delay = filedelay;
2841 			}
2842 			vn_syncer_add_to_worklist(bo, delay);
2843 		}
2844 		buf_vlist_add(bp, bo, BX_VNDIRTY);
2845 	} else {
2846 		buf_vlist_add(bp, bo, BX_VNCLEAN);
2847 
2848 		if ((bo->bo_flag & BO_ONWORKLST) && bo->bo_dirty.bv_cnt == 0) {
2849 			mtx_lock(&sync_mtx);
2850 			LIST_REMOVE(bo, bo_synclist);
2851 			syncer_worklist_len--;
2852 			mtx_unlock(&sync_mtx);
2853 			bo->bo_flag &= ~BO_ONWORKLST;
2854 		}
2855 	}
2856 #ifdef INVARIANTS
2857 	bv = &bo->bo_clean;
2858 	bp = TAILQ_FIRST(&bv->bv_hd);
2859 	KASSERT(bp == NULL || bp->b_bufobj == bo,
2860 	    ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
2861 	bp = TAILQ_LAST(&bv->bv_hd, buflists);
2862 	KASSERT(bp == NULL || bp->b_bufobj == bo,
2863 	    ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
2864 	bv = &bo->bo_dirty;
2865 	bp = TAILQ_FIRST(&bv->bv_hd);
2866 	KASSERT(bp == NULL || bp->b_bufobj == bo,
2867 	    ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
2868 	bp = TAILQ_LAST(&bv->bv_hd, buflists);
2869 	KASSERT(bp == NULL || bp->b_bufobj == bo,
2870 	    ("bp %p wrong b_bufobj %p should be %p", bp, bp->b_bufobj, bo));
2871 #endif
2872 	BO_UNLOCK(bo);
2873 }
2874 
2875 static void
2876 v_init_counters(struct vnode *vp)
2877 {
2878 
2879 	VNASSERT(vp->v_type == VNON && vp->v_data == NULL && vp->v_iflag == 0,
2880 	    vp, ("%s called for an initialized vnode", __FUNCTION__));
2881 	ASSERT_VI_UNLOCKED(vp, __FUNCTION__);
2882 
2883 	refcount_init(&vp->v_holdcnt, 1);
2884 	refcount_init(&vp->v_usecount, 1);
2885 }
2886 
2887 /*
2888  * Grab a particular vnode from the free list, increment its
2889  * reference count and lock it.  VIRF_DOOMED is set if the vnode
2890  * is being destroyed.  Only callers who specify LK_RETRY will
2891  * see doomed vnodes.  If inactive processing was delayed in
2892  * vput try to do it here.
2893  *
2894  * usecount is manipulated using atomics without holding any locks.
2895  *
2896  * holdcnt can be manipulated using atomics without holding any locks,
2897  * except when transitioning 1<->0, in which case the interlock is held.
2898  *
2899  * Consumers which don't guarantee liveness of the vnode can use SMR to
2900  * try to get a reference. Note this operation can fail since the vnode
2901  * may be awaiting getting freed by the time they get to it.
2902  */
2903 enum vgetstate
2904 vget_prep_smr(struct vnode *vp)
2905 {
2906 	enum vgetstate vs;
2907 
2908 	VFS_SMR_ASSERT_ENTERED();
2909 
2910 	if (refcount_acquire_if_not_zero(&vp->v_usecount)) {
2911 		vs = VGET_USECOUNT;
2912 	} else {
2913 		if (vhold_smr(vp))
2914 			vs = VGET_HOLDCNT;
2915 		else
2916 			vs = VGET_NONE;
2917 	}
2918 	return (vs);
2919 }
2920 
2921 enum vgetstate
2922 vget_prep(struct vnode *vp)
2923 {
2924 	enum vgetstate vs;
2925 
2926 	if (refcount_acquire_if_not_zero(&vp->v_usecount)) {
2927 		vs = VGET_USECOUNT;
2928 	} else {
2929 		vhold(vp);
2930 		vs = VGET_HOLDCNT;
2931 	}
2932 	return (vs);
2933 }
2934 
2935 void
2936 vget_abort(struct vnode *vp, enum vgetstate vs)
2937 {
2938 
2939 	switch (vs) {
2940 	case VGET_USECOUNT:
2941 		vrele(vp);
2942 		break;
2943 	case VGET_HOLDCNT:
2944 		vdrop(vp);
2945 		break;
2946 	default:
2947 		__assert_unreachable();
2948 	}
2949 }
2950 
2951 int
2952 vget(struct vnode *vp, int flags)
2953 {
2954 	enum vgetstate vs;
2955 
2956 	vs = vget_prep(vp);
2957 	return (vget_finish(vp, flags, vs));
2958 }
2959 
2960 int
2961 vget_finish(struct vnode *vp, int flags, enum vgetstate vs)
2962 {
2963 	int error;
2964 
2965 	if ((flags & LK_INTERLOCK) != 0)
2966 		ASSERT_VI_LOCKED(vp, __func__);
2967 	else
2968 		ASSERT_VI_UNLOCKED(vp, __func__);
2969 	VNPASS(vs == VGET_HOLDCNT || vs == VGET_USECOUNT, vp);
2970 	VNPASS(vp->v_holdcnt > 0, vp);
2971 	VNPASS(vs == VGET_HOLDCNT || vp->v_usecount > 0, vp);
2972 
2973 	error = vn_lock(vp, flags);
2974 	if (__predict_false(error != 0)) {
2975 		vget_abort(vp, vs);
2976 		CTR2(KTR_VFS, "%s: impossible to lock vnode %p", __func__,
2977 		    vp);
2978 		return (error);
2979 	}
2980 
2981 	vget_finish_ref(vp, vs);
2982 	return (0);
2983 }
2984 
2985 void
2986 vget_finish_ref(struct vnode *vp, enum vgetstate vs)
2987 {
2988 	int old;
2989 
2990 	VNPASS(vs == VGET_HOLDCNT || vs == VGET_USECOUNT, vp);
2991 	VNPASS(vp->v_holdcnt > 0, vp);
2992 	VNPASS(vs == VGET_HOLDCNT || vp->v_usecount > 0, vp);
2993 
2994 	if (vs == VGET_USECOUNT)
2995 		return;
2996 
2997 	/*
2998 	 * We hold the vnode. If the usecount is 0 it will be utilized to keep
2999 	 * the vnode around. Otherwise someone else lended their hold count and
3000 	 * we have to drop ours.
3001 	 */
3002 	old = atomic_fetchadd_int(&vp->v_usecount, 1);
3003 	VNASSERT(old >= 0, vp, ("%s: wrong use count %d", __func__, old));
3004 	if (old != 0) {
3005 #ifdef INVARIANTS
3006 		old = atomic_fetchadd_int(&vp->v_holdcnt, -1);
3007 		VNASSERT(old > 1, vp, ("%s: wrong hold count %d", __func__, old));
3008 #else
3009 		refcount_release(&vp->v_holdcnt);
3010 #endif
3011 	}
3012 }
3013 
3014 void
3015 vref(struct vnode *vp)
3016 {
3017 	enum vgetstate vs;
3018 
3019 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
3020 	vs = vget_prep(vp);
3021 	vget_finish_ref(vp, vs);
3022 }
3023 
3024 void
3025 vrefact(struct vnode *vp)
3026 {
3027 
3028 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
3029 #ifdef INVARIANTS
3030 	int old = atomic_fetchadd_int(&vp->v_usecount, 1);
3031 	VNASSERT(old > 0, vp, ("%s: wrong use count %d", __func__, old));
3032 #else
3033 	refcount_acquire(&vp->v_usecount);
3034 #endif
3035 }
3036 
3037 void
3038 vlazy(struct vnode *vp)
3039 {
3040 	struct mount *mp;
3041 
3042 	VNASSERT(vp->v_holdcnt > 0, vp, ("%s: vnode not held", __func__));
3043 
3044 	if ((vp->v_mflag & VMP_LAZYLIST) != 0)
3045 		return;
3046 	/*
3047 	 * We may get here for inactive routines after the vnode got doomed.
3048 	 */
3049 	if (VN_IS_DOOMED(vp))
3050 		return;
3051 	mp = vp->v_mount;
3052 	mtx_lock(&mp->mnt_listmtx);
3053 	if ((vp->v_mflag & VMP_LAZYLIST) == 0) {
3054 		vp->v_mflag |= VMP_LAZYLIST;
3055 		TAILQ_INSERT_TAIL(&mp->mnt_lazyvnodelist, vp, v_lazylist);
3056 		mp->mnt_lazyvnodelistsize++;
3057 	}
3058 	mtx_unlock(&mp->mnt_listmtx);
3059 }
3060 
3061 /*
3062  * This routine is only meant to be called from vgonel prior to dooming
3063  * the vnode.
3064  */
3065 static void
3066 vunlazy_gone(struct vnode *vp)
3067 {
3068 	struct mount *mp;
3069 
3070 	ASSERT_VOP_ELOCKED(vp, __func__);
3071 	ASSERT_VI_LOCKED(vp, __func__);
3072 	VNPASS(!VN_IS_DOOMED(vp), vp);
3073 
3074 	if (vp->v_mflag & VMP_LAZYLIST) {
3075 		mp = vp->v_mount;
3076 		mtx_lock(&mp->mnt_listmtx);
3077 		VNPASS(vp->v_mflag & VMP_LAZYLIST, vp);
3078 		vp->v_mflag &= ~VMP_LAZYLIST;
3079 		TAILQ_REMOVE(&mp->mnt_lazyvnodelist, vp, v_lazylist);
3080 		mp->mnt_lazyvnodelistsize--;
3081 		mtx_unlock(&mp->mnt_listmtx);
3082 	}
3083 }
3084 
3085 static void
3086 vdefer_inactive(struct vnode *vp)
3087 {
3088 
3089 	ASSERT_VI_LOCKED(vp, __func__);
3090 	VNASSERT(vp->v_holdcnt > 0, vp,
3091 	    ("%s: vnode without hold count", __func__));
3092 	if (VN_IS_DOOMED(vp)) {
3093 		vdropl(vp);
3094 		return;
3095 	}
3096 	if (vp->v_iflag & VI_DEFINACT) {
3097 		VNASSERT(vp->v_holdcnt > 1, vp, ("lost hold count"));
3098 		vdropl(vp);
3099 		return;
3100 	}
3101 	if (vp->v_usecount > 0) {
3102 		vp->v_iflag &= ~VI_OWEINACT;
3103 		vdropl(vp);
3104 		return;
3105 	}
3106 	vlazy(vp);
3107 	vp->v_iflag |= VI_DEFINACT;
3108 	VI_UNLOCK(vp);
3109 	counter_u64_add(deferred_inact, 1);
3110 }
3111 
3112 static void
3113 vdefer_inactive_unlocked(struct vnode *vp)
3114 {
3115 
3116 	VI_LOCK(vp);
3117 	if ((vp->v_iflag & VI_OWEINACT) == 0) {
3118 		vdropl(vp);
3119 		return;
3120 	}
3121 	vdefer_inactive(vp);
3122 }
3123 
3124 enum vput_op { VRELE, VPUT, VUNREF };
3125 
3126 /*
3127  * Handle ->v_usecount transitioning to 0.
3128  *
3129  * By releasing the last usecount we take ownership of the hold count which
3130  * provides liveness of the vnode, meaning we have to vdrop.
3131  *
3132  * For all vnodes we may need to perform inactive processing. It requires an
3133  * exclusive lock on the vnode, while it is legal to call here with only a
3134  * shared lock (or no locks). If locking the vnode in an expected manner fails,
3135  * inactive processing gets deferred to the syncer.
3136  *
3137  * XXX Some filesystems pass in an exclusively locked vnode and strongly depend
3138  * on the lock being held all the way until VOP_INACTIVE. This in particular
3139  * happens with UFS which adds half-constructed vnodes to the hash, where they
3140  * can be found by other code.
3141  */
3142 static void
3143 vput_final(struct vnode *vp, enum vput_op func)
3144 {
3145 	int error;
3146 	bool want_unlock;
3147 
3148 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
3149 	VNPASS(vp->v_holdcnt > 0, vp);
3150 
3151 	VI_LOCK(vp);
3152 
3153 	/*
3154 	 * By the time we got here someone else might have transitioned
3155 	 * the count back to > 0.
3156 	 */
3157 	if (vp->v_usecount > 0)
3158 		goto out;
3159 
3160 	/*
3161 	 * If the vnode is doomed vgone already performed inactive processing
3162 	 * (if needed).
3163 	 */
3164 	if (VN_IS_DOOMED(vp))
3165 		goto out;
3166 
3167 	if (__predict_true(VOP_NEED_INACTIVE(vp) == 0))
3168 		goto out;
3169 
3170 	if (vp->v_iflag & VI_DOINGINACT)
3171 		goto out;
3172 
3173 	/*
3174 	 * Locking operations here will drop the interlock and possibly the
3175 	 * vnode lock, opening a window where the vnode can get doomed all the
3176 	 * while ->v_usecount is 0. Set VI_OWEINACT to let vgone know to
3177 	 * perform inactive.
3178 	 */
3179 	vp->v_iflag |= VI_OWEINACT;
3180 	want_unlock = false;
3181 	error = 0;
3182 	switch (func) {
3183 	case VRELE:
3184 		switch (VOP_ISLOCKED(vp)) {
3185 		case LK_EXCLUSIVE:
3186 			break;
3187 		case LK_EXCLOTHER:
3188 		case 0:
3189 			want_unlock = true;
3190 			error = vn_lock(vp, LK_EXCLUSIVE | LK_INTERLOCK);
3191 			VI_LOCK(vp);
3192 			break;
3193 		default:
3194 			/*
3195 			 * The lock has at least one sharer, but we have no way
3196 			 * to conclude whether this is us. Play it safe and
3197 			 * defer processing.
3198 			 */
3199 			error = EAGAIN;
3200 			break;
3201 		}
3202 		break;
3203 	case VPUT:
3204 		want_unlock = true;
3205 		if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
3206 			error = VOP_LOCK(vp, LK_UPGRADE | LK_INTERLOCK |
3207 			    LK_NOWAIT);
3208 			VI_LOCK(vp);
3209 		}
3210 		break;
3211 	case VUNREF:
3212 		if (VOP_ISLOCKED(vp) != LK_EXCLUSIVE) {
3213 			error = VOP_LOCK(vp, LK_TRYUPGRADE | LK_INTERLOCK);
3214 			VI_LOCK(vp);
3215 		}
3216 		break;
3217 	}
3218 	if (error == 0) {
3219 		if (func == VUNREF) {
3220 			VNASSERT((vp->v_vflag & VV_UNREF) == 0, vp,
3221 			    ("recursive vunref"));
3222 			vp->v_vflag |= VV_UNREF;
3223 		}
3224 		for (;;) {
3225 			error = vinactive(vp);
3226 			if (want_unlock)
3227 				VOP_UNLOCK(vp);
3228 			if (error != ERELOOKUP || !want_unlock)
3229 				break;
3230 			VOP_LOCK(vp, LK_EXCLUSIVE);
3231 		}
3232 		if (func == VUNREF)
3233 			vp->v_vflag &= ~VV_UNREF;
3234 		vdropl(vp);
3235 	} else {
3236 		vdefer_inactive(vp);
3237 	}
3238 	return;
3239 out:
3240 	if (func == VPUT)
3241 		VOP_UNLOCK(vp);
3242 	vdropl(vp);
3243 }
3244 
3245 /*
3246  * Decrement ->v_usecount for a vnode.
3247  *
3248  * Releasing the last use count requires additional processing, see vput_final
3249  * above for details.
3250  *
3251  * Comment above each variant denotes lock state on entry and exit.
3252  */
3253 
3254 /*
3255  * in: any
3256  * out: same as passed in
3257  */
3258 void
3259 vrele(struct vnode *vp)
3260 {
3261 
3262 	ASSERT_VI_UNLOCKED(vp, __func__);
3263 	if (!refcount_release(&vp->v_usecount))
3264 		return;
3265 	vput_final(vp, VRELE);
3266 }
3267 
3268 /*
3269  * in: locked
3270  * out: unlocked
3271  */
3272 void
3273 vput(struct vnode *vp)
3274 {
3275 
3276 	ASSERT_VOP_LOCKED(vp, __func__);
3277 	ASSERT_VI_UNLOCKED(vp, __func__);
3278 	if (!refcount_release(&vp->v_usecount)) {
3279 		VOP_UNLOCK(vp);
3280 		return;
3281 	}
3282 	vput_final(vp, VPUT);
3283 }
3284 
3285 /*
3286  * in: locked
3287  * out: locked
3288  */
3289 void
3290 vunref(struct vnode *vp)
3291 {
3292 
3293 	ASSERT_VOP_LOCKED(vp, __func__);
3294 	ASSERT_VI_UNLOCKED(vp, __func__);
3295 	if (!refcount_release(&vp->v_usecount))
3296 		return;
3297 	vput_final(vp, VUNREF);
3298 }
3299 
3300 void
3301 vhold(struct vnode *vp)
3302 {
3303 	int old;
3304 
3305 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
3306 	old = atomic_fetchadd_int(&vp->v_holdcnt, 1);
3307 	VNASSERT(old >= 0 && (old & VHOLD_ALL_FLAGS) == 0, vp,
3308 	    ("%s: wrong hold count %d", __func__, old));
3309 	if (old == 0)
3310 		vn_freevnodes_dec();
3311 }
3312 
3313 void
3314 vholdnz(struct vnode *vp)
3315 {
3316 
3317 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
3318 #ifdef INVARIANTS
3319 	int old = atomic_fetchadd_int(&vp->v_holdcnt, 1);
3320 	VNASSERT(old > 0 && (old & VHOLD_ALL_FLAGS) == 0, vp,
3321 	    ("%s: wrong hold count %d", __func__, old));
3322 #else
3323 	atomic_add_int(&vp->v_holdcnt, 1);
3324 #endif
3325 }
3326 
3327 /*
3328  * Grab a hold count unless the vnode is freed.
3329  *
3330  * Only use this routine if vfs smr is the only protection you have against
3331  * freeing the vnode.
3332  *
3333  * The code loops trying to add a hold count as long as the VHOLD_NO_SMR flag
3334  * is not set.  After the flag is set the vnode becomes immutable to anyone but
3335  * the thread which managed to set the flag.
3336  *
3337  * It may be tempting to replace the loop with:
3338  * count = atomic_fetchadd_int(&vp->v_holdcnt, 1);
3339  * if (count & VHOLD_NO_SMR) {
3340  *     backpedal and error out;
3341  * }
3342  *
3343  * However, while this is more performant, it hinders debugging by eliminating
3344  * the previously mentioned invariant.
3345  */
3346 bool
3347 vhold_smr(struct vnode *vp)
3348 {
3349 	int count;
3350 
3351 	VFS_SMR_ASSERT_ENTERED();
3352 
3353 	count = atomic_load_int(&vp->v_holdcnt);
3354 	for (;;) {
3355 		if (count & VHOLD_NO_SMR) {
3356 			VNASSERT((count & ~VHOLD_NO_SMR) == 0, vp,
3357 			    ("non-zero hold count with flags %d\n", count));
3358 			return (false);
3359 		}
3360 		VNASSERT(count >= 0, vp, ("invalid hold count %d\n", count));
3361 		if (atomic_fcmpset_int(&vp->v_holdcnt, &count, count + 1)) {
3362 			if (count == 0)
3363 				vn_freevnodes_dec();
3364 			return (true);
3365 		}
3366 	}
3367 }
3368 
3369 /*
3370  * Hold a free vnode for recycling.
3371  *
3372  * Note: vnode_init references this comment.
3373  *
3374  * Attempts to recycle only need the global vnode list lock and have no use for
3375  * SMR.
3376  *
3377  * However, vnodes get inserted into the global list before they get fully
3378  * initialized and stay there until UMA decides to free the memory. This in
3379  * particular means the target can be found before it becomes usable and after
3380  * it becomes recycled. Picking up such vnodes is guarded with v_holdcnt set to
3381  * VHOLD_NO_SMR.
3382  *
3383  * Note: the vnode may gain more references after we transition the count 0->1.
3384  */
3385 static bool
3386 vhold_recycle_free(struct vnode *vp)
3387 {
3388 	int count;
3389 
3390 	mtx_assert(&vnode_list_mtx, MA_OWNED);
3391 
3392 	count = atomic_load_int(&vp->v_holdcnt);
3393 	for (;;) {
3394 		if (count & VHOLD_NO_SMR) {
3395 			VNASSERT((count & ~VHOLD_NO_SMR) == 0, vp,
3396 			    ("non-zero hold count with flags %d\n", count));
3397 			return (false);
3398 		}
3399 		VNASSERT(count >= 0, vp, ("invalid hold count %d\n", count));
3400 		if (count > 0) {
3401 			return (false);
3402 		}
3403 		if (atomic_fcmpset_int(&vp->v_holdcnt, &count, count + 1)) {
3404 			vn_freevnodes_dec();
3405 			return (true);
3406 		}
3407 	}
3408 }
3409 
3410 static void __noinline
3411 vdbatch_process(struct vdbatch *vd)
3412 {
3413 	struct vnode *vp;
3414 	int i;
3415 
3416 	mtx_assert(&vd->lock, MA_OWNED);
3417 	MPASS(curthread->td_pinned > 0);
3418 	MPASS(vd->index == VDBATCH_SIZE);
3419 
3420 	mtx_lock(&vnode_list_mtx);
3421 	critical_enter();
3422 	freevnodes += vd->freevnodes;
3423 	for (i = 0; i < VDBATCH_SIZE; i++) {
3424 		vp = vd->tab[i];
3425 		TAILQ_REMOVE(&vnode_list, vp, v_vnodelist);
3426 		TAILQ_INSERT_TAIL(&vnode_list, vp, v_vnodelist);
3427 		MPASS(vp->v_dbatchcpu != NOCPU);
3428 		vp->v_dbatchcpu = NOCPU;
3429 	}
3430 	mtx_unlock(&vnode_list_mtx);
3431 	vd->freevnodes = 0;
3432 	bzero(vd->tab, sizeof(vd->tab));
3433 	vd->index = 0;
3434 	critical_exit();
3435 }
3436 
3437 static void
3438 vdbatch_enqueue(struct vnode *vp)
3439 {
3440 	struct vdbatch *vd;
3441 
3442 	ASSERT_VI_LOCKED(vp, __func__);
3443 	VNASSERT(!VN_IS_DOOMED(vp), vp,
3444 	    ("%s: deferring requeue of a doomed vnode", __func__));
3445 
3446 	if (vp->v_dbatchcpu != NOCPU) {
3447 		VI_UNLOCK(vp);
3448 		return;
3449 	}
3450 
3451 	sched_pin();
3452 	vd = DPCPU_PTR(vd);
3453 	mtx_lock(&vd->lock);
3454 	MPASS(vd->index < VDBATCH_SIZE);
3455 	MPASS(vd->tab[vd->index] == NULL);
3456 	/*
3457 	 * A hack: we depend on being pinned so that we know what to put in
3458 	 * ->v_dbatchcpu.
3459 	 */
3460 	vp->v_dbatchcpu = curcpu;
3461 	vd->tab[vd->index] = vp;
3462 	vd->index++;
3463 	VI_UNLOCK(vp);
3464 	if (vd->index == VDBATCH_SIZE)
3465 		vdbatch_process(vd);
3466 	mtx_unlock(&vd->lock);
3467 	sched_unpin();
3468 }
3469 
3470 /*
3471  * This routine must only be called for vnodes which are about to be
3472  * deallocated. Supporting dequeue for arbitrary vndoes would require
3473  * validating that the locked batch matches.
3474  */
3475 static void
3476 vdbatch_dequeue(struct vnode *vp)
3477 {
3478 	struct vdbatch *vd;
3479 	int i;
3480 	short cpu;
3481 
3482 	VNASSERT(vp->v_type == VBAD || vp->v_type == VNON, vp,
3483 	    ("%s: called for a used vnode\n", __func__));
3484 
3485 	cpu = vp->v_dbatchcpu;
3486 	if (cpu == NOCPU)
3487 		return;
3488 
3489 	vd = DPCPU_ID_PTR(cpu, vd);
3490 	mtx_lock(&vd->lock);
3491 	for (i = 0; i < vd->index; i++) {
3492 		if (vd->tab[i] != vp)
3493 			continue;
3494 		vp->v_dbatchcpu = NOCPU;
3495 		vd->index--;
3496 		vd->tab[i] = vd->tab[vd->index];
3497 		vd->tab[vd->index] = NULL;
3498 		break;
3499 	}
3500 	mtx_unlock(&vd->lock);
3501 	/*
3502 	 * Either we dequeued the vnode above or the target CPU beat us to it.
3503 	 */
3504 	MPASS(vp->v_dbatchcpu == NOCPU);
3505 }
3506 
3507 /*
3508  * Drop the hold count of the vnode.  If this is the last reference to
3509  * the vnode we place it on the free list unless it has been vgone'd
3510  * (marked VIRF_DOOMED) in which case we will free it.
3511  *
3512  * Because the vnode vm object keeps a hold reference on the vnode if
3513  * there is at least one resident non-cached page, the vnode cannot
3514  * leave the active list without the page cleanup done.
3515  */
3516 static void
3517 vdrop_deactivate(struct vnode *vp)
3518 {
3519 	struct mount *mp;
3520 
3521 	ASSERT_VI_LOCKED(vp, __func__);
3522 	/*
3523 	 * Mark a vnode as free: remove it from its active list
3524 	 * and put it up for recycling on the freelist.
3525 	 */
3526 	VNASSERT(!VN_IS_DOOMED(vp), vp,
3527 	    ("vdrop: returning doomed vnode"));
3528 	VNASSERT((vp->v_iflag & VI_OWEINACT) == 0, vp,
3529 	    ("vnode with VI_OWEINACT set"));
3530 	VNASSERT((vp->v_iflag & VI_DEFINACT) == 0, vp,
3531 	    ("vnode with VI_DEFINACT set"));
3532 	if (vp->v_mflag & VMP_LAZYLIST) {
3533 		mp = vp->v_mount;
3534 		mtx_lock(&mp->mnt_listmtx);
3535 		VNASSERT(vp->v_mflag & VMP_LAZYLIST, vp, ("lost VMP_LAZYLIST"));
3536 		/*
3537 		 * Don't remove the vnode from the lazy list if another thread
3538 		 * has increased the hold count. It may have re-enqueued the
3539 		 * vnode to the lazy list and is now responsible for its
3540 		 * removal.
3541 		 */
3542 		if (vp->v_holdcnt == 0) {
3543 			vp->v_mflag &= ~VMP_LAZYLIST;
3544 			TAILQ_REMOVE(&mp->mnt_lazyvnodelist, vp, v_lazylist);
3545 			mp->mnt_lazyvnodelistsize--;
3546 		}
3547 		mtx_unlock(&mp->mnt_listmtx);
3548 	}
3549 	vdbatch_enqueue(vp);
3550 }
3551 
3552 static void __noinline
3553 vdropl_final(struct vnode *vp)
3554 {
3555 
3556 	ASSERT_VI_LOCKED(vp, __func__);
3557 	VNPASS(VN_IS_DOOMED(vp), vp);
3558 	/*
3559 	 * Set the VHOLD_NO_SMR flag.
3560 	 *
3561 	 * We may be racing against vhold_smr. If they win we can just pretend
3562 	 * we never got this far, they will vdrop later.
3563 	 */
3564 	if (__predict_false(!atomic_cmpset_int(&vp->v_holdcnt, 0, VHOLD_NO_SMR))) {
3565 		vn_freevnodes_inc();
3566 		VI_UNLOCK(vp);
3567 		/*
3568 		 * We lost the aforementioned race. Any subsequent access is
3569 		 * invalid as they might have managed to vdropl on their own.
3570 		 */
3571 		return;
3572 	}
3573 	/*
3574 	 * Don't bump freevnodes as this one is going away.
3575 	 */
3576 	freevnode(vp);
3577 }
3578 
3579 void
3580 vdrop(struct vnode *vp)
3581 {
3582 
3583 	ASSERT_VI_UNLOCKED(vp, __func__);
3584 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
3585 	if (refcount_release_if_not_last(&vp->v_holdcnt))
3586 		return;
3587 	VI_LOCK(vp);
3588 	vdropl(vp);
3589 }
3590 
3591 void
3592 vdropl(struct vnode *vp)
3593 {
3594 
3595 	ASSERT_VI_LOCKED(vp, __func__);
3596 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
3597 	if (!refcount_release(&vp->v_holdcnt)) {
3598 		VI_UNLOCK(vp);
3599 		return;
3600 	}
3601 	if (!VN_IS_DOOMED(vp)) {
3602 		vn_freevnodes_inc();
3603 		vdrop_deactivate(vp);
3604 		/*
3605 		 * Also unlocks the interlock. We can't assert on it as we
3606 		 * released our hold and by now the vnode might have been
3607 		 * freed.
3608 		 */
3609 		return;
3610 	}
3611 	vdropl_final(vp);
3612 }
3613 
3614 /*
3615  * Call VOP_INACTIVE on the vnode and manage the DOINGINACT and OWEINACT
3616  * flags.  DOINGINACT prevents us from recursing in calls to vinactive.
3617  */
3618 static int
3619 vinactivef(struct vnode *vp)
3620 {
3621 	struct vm_object *obj;
3622 	int error;
3623 
3624 	ASSERT_VOP_ELOCKED(vp, "vinactive");
3625 	ASSERT_VI_LOCKED(vp, "vinactive");
3626 	VNASSERT((vp->v_iflag & VI_DOINGINACT) == 0, vp,
3627 	    ("vinactive: recursed on VI_DOINGINACT"));
3628 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
3629 	vp->v_iflag |= VI_DOINGINACT;
3630 	vp->v_iflag &= ~VI_OWEINACT;
3631 	VI_UNLOCK(vp);
3632 	/*
3633 	 * Before moving off the active list, we must be sure that any
3634 	 * modified pages are converted into the vnode's dirty
3635 	 * buffers, since these will no longer be checked once the
3636 	 * vnode is on the inactive list.
3637 	 *
3638 	 * The write-out of the dirty pages is asynchronous.  At the
3639 	 * point that VOP_INACTIVE() is called, there could still be
3640 	 * pending I/O and dirty pages in the object.
3641 	 */
3642 	if ((obj = vp->v_object) != NULL && (vp->v_vflag & VV_NOSYNC) == 0 &&
3643 	    vm_object_mightbedirty(obj)) {
3644 		VM_OBJECT_WLOCK(obj);
3645 		vm_object_page_clean(obj, 0, 0, 0);
3646 		VM_OBJECT_WUNLOCK(obj);
3647 	}
3648 	error = VOP_INACTIVE(vp);
3649 	VI_LOCK(vp);
3650 	VNASSERT(vp->v_iflag & VI_DOINGINACT, vp,
3651 	    ("vinactive: lost VI_DOINGINACT"));
3652 	vp->v_iflag &= ~VI_DOINGINACT;
3653 	return (error);
3654 }
3655 
3656 int
3657 vinactive(struct vnode *vp)
3658 {
3659 
3660 	ASSERT_VOP_ELOCKED(vp, "vinactive");
3661 	ASSERT_VI_LOCKED(vp, "vinactive");
3662 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
3663 
3664 	if ((vp->v_iflag & VI_OWEINACT) == 0)
3665 		return (0);
3666 	if (vp->v_iflag & VI_DOINGINACT)
3667 		return (0);
3668 	if (vp->v_usecount > 0) {
3669 		vp->v_iflag &= ~VI_OWEINACT;
3670 		return (0);
3671 	}
3672 	return (vinactivef(vp));
3673 }
3674 
3675 /*
3676  * Remove any vnodes in the vnode table belonging to mount point mp.
3677  *
3678  * If FORCECLOSE is not specified, there should not be any active ones,
3679  * return error if any are found (nb: this is a user error, not a
3680  * system error). If FORCECLOSE is specified, detach any active vnodes
3681  * that are found.
3682  *
3683  * If WRITECLOSE is set, only flush out regular file vnodes open for
3684  * writing.
3685  *
3686  * SKIPSYSTEM causes any vnodes marked VV_SYSTEM to be skipped.
3687  *
3688  * `rootrefs' specifies the base reference count for the root vnode
3689  * of this filesystem. The root vnode is considered busy if its
3690  * v_usecount exceeds this value. On a successful return, vflush(, td)
3691  * will call vrele() on the root vnode exactly rootrefs times.
3692  * If the SKIPSYSTEM or WRITECLOSE flags are specified, rootrefs must
3693  * be zero.
3694  */
3695 #ifdef DIAGNOSTIC
3696 static int busyprt = 0;		/* print out busy vnodes */
3697 SYSCTL_INT(_debug, OID_AUTO, busyprt, CTLFLAG_RW, &busyprt, 0, "Print out busy vnodes");
3698 #endif
3699 
3700 int
3701 vflush(struct mount *mp, int rootrefs, int flags, struct thread *td)
3702 {
3703 	struct vnode *vp, *mvp, *rootvp = NULL;
3704 	struct vattr vattr;
3705 	int busy = 0, error;
3706 
3707 	CTR4(KTR_VFS, "%s: mp %p with rootrefs %d and flags %d", __func__, mp,
3708 	    rootrefs, flags);
3709 	if (rootrefs > 0) {
3710 		KASSERT((flags & (SKIPSYSTEM | WRITECLOSE)) == 0,
3711 		    ("vflush: bad args"));
3712 		/*
3713 		 * Get the filesystem root vnode. We can vput() it
3714 		 * immediately, since with rootrefs > 0, it won't go away.
3715 		 */
3716 		if ((error = VFS_ROOT(mp, LK_EXCLUSIVE, &rootvp)) != 0) {
3717 			CTR2(KTR_VFS, "%s: vfs_root lookup failed with %d",
3718 			    __func__, error);
3719 			return (error);
3720 		}
3721 		vput(rootvp);
3722 	}
3723 loop:
3724 	MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
3725 		vholdl(vp);
3726 		error = vn_lock(vp, LK_INTERLOCK | LK_EXCLUSIVE);
3727 		if (error) {
3728 			vdrop(vp);
3729 			MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
3730 			goto loop;
3731 		}
3732 		/*
3733 		 * Skip over a vnodes marked VV_SYSTEM.
3734 		 */
3735 		if ((flags & SKIPSYSTEM) && (vp->v_vflag & VV_SYSTEM)) {
3736 			VOP_UNLOCK(vp);
3737 			vdrop(vp);
3738 			continue;
3739 		}
3740 		/*
3741 		 * If WRITECLOSE is set, flush out unlinked but still open
3742 		 * files (even if open only for reading) and regular file
3743 		 * vnodes open for writing.
3744 		 */
3745 		if (flags & WRITECLOSE) {
3746 			if (vp->v_object != NULL) {
3747 				VM_OBJECT_WLOCK(vp->v_object);
3748 				vm_object_page_clean(vp->v_object, 0, 0, 0);
3749 				VM_OBJECT_WUNLOCK(vp->v_object);
3750 			}
3751 			do {
3752 				error = VOP_FSYNC(vp, MNT_WAIT, td);
3753 			} while (error == ERELOOKUP);
3754 			if (error != 0) {
3755 				VOP_UNLOCK(vp);
3756 				vdrop(vp);
3757 				MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
3758 				return (error);
3759 			}
3760 			error = VOP_GETATTR(vp, &vattr, td->td_ucred);
3761 			VI_LOCK(vp);
3762 
3763 			if ((vp->v_type == VNON ||
3764 			    (error == 0 && vattr.va_nlink > 0)) &&
3765 			    (vp->v_writecount <= 0 || vp->v_type != VREG)) {
3766 				VOP_UNLOCK(vp);
3767 				vdropl(vp);
3768 				continue;
3769 			}
3770 		} else
3771 			VI_LOCK(vp);
3772 		/*
3773 		 * With v_usecount == 0, all we need to do is clear out the
3774 		 * vnode data structures and we are done.
3775 		 *
3776 		 * If FORCECLOSE is set, forcibly close the vnode.
3777 		 */
3778 		if (vp->v_usecount == 0 || (flags & FORCECLOSE)) {
3779 			vgonel(vp);
3780 		} else {
3781 			busy++;
3782 #ifdef DIAGNOSTIC
3783 			if (busyprt)
3784 				vn_printf(vp, "vflush: busy vnode ");
3785 #endif
3786 		}
3787 		VOP_UNLOCK(vp);
3788 		vdropl(vp);
3789 	}
3790 	if (rootrefs > 0 && (flags & FORCECLOSE) == 0) {
3791 		/*
3792 		 * If just the root vnode is busy, and if its refcount
3793 		 * is equal to `rootrefs', then go ahead and kill it.
3794 		 */
3795 		VI_LOCK(rootvp);
3796 		KASSERT(busy > 0, ("vflush: not busy"));
3797 		VNASSERT(rootvp->v_usecount >= rootrefs, rootvp,
3798 		    ("vflush: usecount %d < rootrefs %d",
3799 		     rootvp->v_usecount, rootrefs));
3800 		if (busy == 1 && rootvp->v_usecount == rootrefs) {
3801 			VOP_LOCK(rootvp, LK_EXCLUSIVE|LK_INTERLOCK);
3802 			vgone(rootvp);
3803 			VOP_UNLOCK(rootvp);
3804 			busy = 0;
3805 		} else
3806 			VI_UNLOCK(rootvp);
3807 	}
3808 	if (busy) {
3809 		CTR2(KTR_VFS, "%s: failing as %d vnodes are busy", __func__,
3810 		    busy);
3811 		return (EBUSY);
3812 	}
3813 	for (; rootrefs > 0; rootrefs--)
3814 		vrele(rootvp);
3815 	return (0);
3816 }
3817 
3818 /*
3819  * Recycle an unused vnode to the front of the free list.
3820  */
3821 int
3822 vrecycle(struct vnode *vp)
3823 {
3824 	int recycled;
3825 
3826 	VI_LOCK(vp);
3827 	recycled = vrecyclel(vp);
3828 	VI_UNLOCK(vp);
3829 	return (recycled);
3830 }
3831 
3832 /*
3833  * vrecycle, with the vp interlock held.
3834  */
3835 int
3836 vrecyclel(struct vnode *vp)
3837 {
3838 	int recycled;
3839 
3840 	ASSERT_VOP_ELOCKED(vp, __func__);
3841 	ASSERT_VI_LOCKED(vp, __func__);
3842 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
3843 	recycled = 0;
3844 	if (vp->v_usecount == 0) {
3845 		recycled = 1;
3846 		vgonel(vp);
3847 	}
3848 	return (recycled);
3849 }
3850 
3851 /*
3852  * Eliminate all activity associated with a vnode
3853  * in preparation for reuse.
3854  */
3855 void
3856 vgone(struct vnode *vp)
3857 {
3858 	VI_LOCK(vp);
3859 	vgonel(vp);
3860 	VI_UNLOCK(vp);
3861 }
3862 
3863 static void
3864 notify_lowervp_vfs_dummy(struct mount *mp __unused,
3865     struct vnode *lowervp __unused)
3866 {
3867 }
3868 
3869 /*
3870  * Notify upper mounts about reclaimed or unlinked vnode.
3871  */
3872 void
3873 vfs_notify_upper(struct vnode *vp, int event)
3874 {
3875 	static struct vfsops vgonel_vfsops = {
3876 		.vfs_reclaim_lowervp = notify_lowervp_vfs_dummy,
3877 		.vfs_unlink_lowervp = notify_lowervp_vfs_dummy,
3878 	};
3879 	struct mount *mp, *ump, *mmp;
3880 
3881 	mp = vp->v_mount;
3882 	if (mp == NULL)
3883 		return;
3884 	if (TAILQ_EMPTY(&mp->mnt_uppers))
3885 		return;
3886 
3887 	mmp = malloc(sizeof(struct mount), M_TEMP, M_WAITOK | M_ZERO);
3888 	mmp->mnt_op = &vgonel_vfsops;
3889 	mmp->mnt_kern_flag |= MNTK_MARKER;
3890 	MNT_ILOCK(mp);
3891 	mp->mnt_kern_flag |= MNTK_VGONE_UPPER;
3892 	for (ump = TAILQ_FIRST(&mp->mnt_uppers); ump != NULL;) {
3893 		if ((ump->mnt_kern_flag & MNTK_MARKER) != 0) {
3894 			ump = TAILQ_NEXT(ump, mnt_upper_link);
3895 			continue;
3896 		}
3897 		TAILQ_INSERT_AFTER(&mp->mnt_uppers, ump, mmp, mnt_upper_link);
3898 		MNT_IUNLOCK(mp);
3899 		switch (event) {
3900 		case VFS_NOTIFY_UPPER_RECLAIM:
3901 			VFS_RECLAIM_LOWERVP(ump, vp);
3902 			break;
3903 		case VFS_NOTIFY_UPPER_UNLINK:
3904 			VFS_UNLINK_LOWERVP(ump, vp);
3905 			break;
3906 		default:
3907 			KASSERT(0, ("invalid event %d", event));
3908 			break;
3909 		}
3910 		MNT_ILOCK(mp);
3911 		ump = TAILQ_NEXT(mmp, mnt_upper_link);
3912 		TAILQ_REMOVE(&mp->mnt_uppers, mmp, mnt_upper_link);
3913 	}
3914 	free(mmp, M_TEMP);
3915 	mp->mnt_kern_flag &= ~MNTK_VGONE_UPPER;
3916 	if ((mp->mnt_kern_flag & MNTK_VGONE_WAITER) != 0) {
3917 		mp->mnt_kern_flag &= ~MNTK_VGONE_WAITER;
3918 		wakeup(&mp->mnt_uppers);
3919 	}
3920 	MNT_IUNLOCK(mp);
3921 }
3922 
3923 /*
3924  * vgone, with the vp interlock held.
3925  */
3926 static void
3927 vgonel(struct vnode *vp)
3928 {
3929 	struct thread *td;
3930 	struct mount *mp;
3931 	vm_object_t object;
3932 	bool active, doinginact, oweinact;
3933 
3934 	ASSERT_VOP_ELOCKED(vp, "vgonel");
3935 	ASSERT_VI_LOCKED(vp, "vgonel");
3936 	VNASSERT(vp->v_holdcnt, vp,
3937 	    ("vgonel: vp %p has no reference.", vp));
3938 	CTR2(KTR_VFS, "%s: vp %p", __func__, vp);
3939 	td = curthread;
3940 
3941 	/*
3942 	 * Don't vgonel if we're already doomed.
3943 	 */
3944 	if (VN_IS_DOOMED(vp))
3945 		return;
3946 	/*
3947 	 * Paired with freevnode.
3948 	 */
3949 	vn_seqc_write_begin_locked(vp);
3950 	vunlazy_gone(vp);
3951 	vn_irflag_set_locked(vp, VIRF_DOOMED);
3952 
3953 	/*
3954 	 * Check to see if the vnode is in use.  If so, we have to
3955 	 * call VOP_CLOSE() and VOP_INACTIVE().
3956 	 *
3957 	 * It could be that VOP_INACTIVE() requested reclamation, in
3958 	 * which case we should avoid recursion, so check
3959 	 * VI_DOINGINACT.  This is not precise but good enough.
3960 	 */
3961 	active = vp->v_usecount > 0;
3962 	oweinact = (vp->v_iflag & VI_OWEINACT) != 0;
3963 	doinginact = (vp->v_iflag & VI_DOINGINACT) != 0;
3964 
3965 	/*
3966 	 * If we need to do inactive VI_OWEINACT will be set.
3967 	 */
3968 	if (vp->v_iflag & VI_DEFINACT) {
3969 		VNASSERT(vp->v_holdcnt > 1, vp, ("lost hold count"));
3970 		vp->v_iflag &= ~VI_DEFINACT;
3971 		vdropl(vp);
3972 	} else {
3973 		VNASSERT(vp->v_holdcnt > 0, vp, ("vnode without hold count"));
3974 		VI_UNLOCK(vp);
3975 	}
3976 	cache_purge_vgone(vp);
3977 	vfs_notify_upper(vp, VFS_NOTIFY_UPPER_RECLAIM);
3978 
3979 	/*
3980 	 * If purging an active vnode, it must be closed and
3981 	 * deactivated before being reclaimed.
3982 	 */
3983 	if (active)
3984 		VOP_CLOSE(vp, FNONBLOCK, NOCRED, td);
3985 	if (!doinginact) {
3986 		do {
3987 			if (oweinact || active) {
3988 				VI_LOCK(vp);
3989 				vinactivef(vp);
3990 				oweinact = (vp->v_iflag & VI_OWEINACT) != 0;
3991 				VI_UNLOCK(vp);
3992 			}
3993 		} while (oweinact);
3994 	}
3995 	if (vp->v_type == VSOCK)
3996 		vfs_unp_reclaim(vp);
3997 
3998 	/*
3999 	 * Clean out any buffers associated with the vnode.
4000 	 * If the flush fails, just toss the buffers.
4001 	 */
4002 	mp = NULL;
4003 	if (!TAILQ_EMPTY(&vp->v_bufobj.bo_dirty.bv_hd))
4004 		(void) vn_start_secondary_write(vp, &mp, V_WAIT);
4005 	if (vinvalbuf(vp, V_SAVE, 0, 0) != 0) {
4006 		while (vinvalbuf(vp, 0, 0, 0) != 0)
4007 			;
4008 	}
4009 
4010 	BO_LOCK(&vp->v_bufobj);
4011 	KASSERT(TAILQ_EMPTY(&vp->v_bufobj.bo_dirty.bv_hd) &&
4012 	    vp->v_bufobj.bo_dirty.bv_cnt == 0 &&
4013 	    TAILQ_EMPTY(&vp->v_bufobj.bo_clean.bv_hd) &&
4014 	    vp->v_bufobj.bo_clean.bv_cnt == 0,
4015 	    ("vp %p bufobj not invalidated", vp));
4016 
4017 	/*
4018 	 * For VMIO bufobj, BO_DEAD is set later, or in
4019 	 * vm_object_terminate() after the object's page queue is
4020 	 * flushed.
4021 	 */
4022 	object = vp->v_bufobj.bo_object;
4023 	if (object == NULL)
4024 		vp->v_bufobj.bo_flag |= BO_DEAD;
4025 	BO_UNLOCK(&vp->v_bufobj);
4026 
4027 	/*
4028 	 * Handle the VM part.  Tmpfs handles v_object on its own (the
4029 	 * OBJT_VNODE check).  Nullfs or other bypassing filesystems
4030 	 * should not touch the object borrowed from the lower vnode
4031 	 * (the handle check).
4032 	 */
4033 	if (object != NULL && object->type == OBJT_VNODE &&
4034 	    object->handle == vp)
4035 		vnode_destroy_vobject(vp);
4036 
4037 	/*
4038 	 * Reclaim the vnode.
4039 	 */
4040 	if (VOP_RECLAIM(vp))
4041 		panic("vgone: cannot reclaim");
4042 	if (mp != NULL)
4043 		vn_finished_secondary_write(mp);
4044 	VNASSERT(vp->v_object == NULL, vp,
4045 	    ("vop_reclaim left v_object vp=%p", vp));
4046 	/*
4047 	 * Clear the advisory locks and wake up waiting threads.
4048 	 */
4049 	(void)VOP_ADVLOCKPURGE(vp);
4050 	vp->v_lockf = NULL;
4051 	/*
4052 	 * Delete from old mount point vnode list.
4053 	 */
4054 	delmntque(vp);
4055 	/*
4056 	 * Done with purge, reset to the standard lock and invalidate
4057 	 * the vnode.
4058 	 */
4059 	VI_LOCK(vp);
4060 	vp->v_vnlock = &vp->v_lock;
4061 	vp->v_op = &dead_vnodeops;
4062 	vp->v_type = VBAD;
4063 }
4064 
4065 /*
4066  * Print out a description of a vnode.
4067  */
4068 static const char * const typename[] =
4069 {"VNON", "VREG", "VDIR", "VBLK", "VCHR", "VLNK", "VSOCK", "VFIFO", "VBAD",
4070  "VMARKER"};
4071 
4072 _Static_assert((VHOLD_ALL_FLAGS & ~VHOLD_NO_SMR) == 0,
4073     "new hold count flag not added to vn_printf");
4074 
4075 void
4076 vn_printf(struct vnode *vp, const char *fmt, ...)
4077 {
4078 	va_list ap;
4079 	char buf[256], buf2[16];
4080 	u_long flags;
4081 	u_int holdcnt;
4082 	short irflag;
4083 
4084 	va_start(ap, fmt);
4085 	vprintf(fmt, ap);
4086 	va_end(ap);
4087 	printf("%p: ", (void *)vp);
4088 	printf("type %s\n", typename[vp->v_type]);
4089 	holdcnt = atomic_load_int(&vp->v_holdcnt);
4090 	printf("    usecount %d, writecount %d, refcount %d seqc users %d",
4091 	    vp->v_usecount, vp->v_writecount, holdcnt & ~VHOLD_ALL_FLAGS,
4092 	    vp->v_seqc_users);
4093 	switch (vp->v_type) {
4094 	case VDIR:
4095 		printf(" mountedhere %p\n", vp->v_mountedhere);
4096 		break;
4097 	case VCHR:
4098 		printf(" rdev %p\n", vp->v_rdev);
4099 		break;
4100 	case VSOCK:
4101 		printf(" socket %p\n", vp->v_unpcb);
4102 		break;
4103 	case VFIFO:
4104 		printf(" fifoinfo %p\n", vp->v_fifoinfo);
4105 		break;
4106 	default:
4107 		printf("\n");
4108 		break;
4109 	}
4110 	buf[0] = '\0';
4111 	buf[1] = '\0';
4112 	if (holdcnt & VHOLD_NO_SMR)
4113 		strlcat(buf, "|VHOLD_NO_SMR", sizeof(buf));
4114 	printf("    hold count flags (%s)\n", buf + 1);
4115 
4116 	buf[0] = '\0';
4117 	buf[1] = '\0';
4118 	irflag = vn_irflag_read(vp);
4119 	if (irflag & VIRF_DOOMED)
4120 		strlcat(buf, "|VIRF_DOOMED", sizeof(buf));
4121 	if (irflag & VIRF_PGREAD)
4122 		strlcat(buf, "|VIRF_PGREAD", sizeof(buf));
4123 	if (irflag & VIRF_MOUNTPOINT)
4124 		strlcat(buf, "|VIRF_MOUNTPOINT", sizeof(buf));
4125 	flags = irflag & ~(VIRF_DOOMED | VIRF_PGREAD | VIRF_MOUNTPOINT);
4126 	if (flags != 0) {
4127 		snprintf(buf2, sizeof(buf2), "|VIRF(0x%lx)", flags);
4128 		strlcat(buf, buf2, sizeof(buf));
4129 	}
4130 	if (vp->v_vflag & VV_ROOT)
4131 		strlcat(buf, "|VV_ROOT", sizeof(buf));
4132 	if (vp->v_vflag & VV_ISTTY)
4133 		strlcat(buf, "|VV_ISTTY", sizeof(buf));
4134 	if (vp->v_vflag & VV_NOSYNC)
4135 		strlcat(buf, "|VV_NOSYNC", sizeof(buf));
4136 	if (vp->v_vflag & VV_ETERNALDEV)
4137 		strlcat(buf, "|VV_ETERNALDEV", sizeof(buf));
4138 	if (vp->v_vflag & VV_CACHEDLABEL)
4139 		strlcat(buf, "|VV_CACHEDLABEL", sizeof(buf));
4140 	if (vp->v_vflag & VV_VMSIZEVNLOCK)
4141 		strlcat(buf, "|VV_VMSIZEVNLOCK", sizeof(buf));
4142 	if (vp->v_vflag & VV_COPYONWRITE)
4143 		strlcat(buf, "|VV_COPYONWRITE", sizeof(buf));
4144 	if (vp->v_vflag & VV_SYSTEM)
4145 		strlcat(buf, "|VV_SYSTEM", sizeof(buf));
4146 	if (vp->v_vflag & VV_PROCDEP)
4147 		strlcat(buf, "|VV_PROCDEP", sizeof(buf));
4148 	if (vp->v_vflag & VV_NOKNOTE)
4149 		strlcat(buf, "|VV_NOKNOTE", sizeof(buf));
4150 	if (vp->v_vflag & VV_DELETED)
4151 		strlcat(buf, "|VV_DELETED", sizeof(buf));
4152 	if (vp->v_vflag & VV_MD)
4153 		strlcat(buf, "|VV_MD", sizeof(buf));
4154 	if (vp->v_vflag & VV_FORCEINSMQ)
4155 		strlcat(buf, "|VV_FORCEINSMQ", sizeof(buf));
4156 	if (vp->v_vflag & VV_READLINK)
4157 		strlcat(buf, "|VV_READLINK", sizeof(buf));
4158 	flags = vp->v_vflag & ~(VV_ROOT | VV_ISTTY | VV_NOSYNC | VV_ETERNALDEV |
4159 	    VV_CACHEDLABEL | VV_VMSIZEVNLOCK | VV_COPYONWRITE | VV_SYSTEM |
4160 	    VV_PROCDEP | VV_NOKNOTE | VV_DELETED | VV_MD | VV_FORCEINSMQ |
4161 	    VV_READLINK);
4162 	if (flags != 0) {
4163 		snprintf(buf2, sizeof(buf2), "|VV(0x%lx)", flags);
4164 		strlcat(buf, buf2, sizeof(buf));
4165 	}
4166 	if (vp->v_iflag & VI_TEXT_REF)
4167 		strlcat(buf, "|VI_TEXT_REF", sizeof(buf));
4168 	if (vp->v_iflag & VI_MOUNT)
4169 		strlcat(buf, "|VI_MOUNT", sizeof(buf));
4170 	if (vp->v_iflag & VI_DOINGINACT)
4171 		strlcat(buf, "|VI_DOINGINACT", sizeof(buf));
4172 	if (vp->v_iflag & VI_OWEINACT)
4173 		strlcat(buf, "|VI_OWEINACT", sizeof(buf));
4174 	if (vp->v_iflag & VI_DEFINACT)
4175 		strlcat(buf, "|VI_DEFINACT", sizeof(buf));
4176 	if (vp->v_iflag & VI_FOPENING)
4177 		strlcat(buf, "|VI_FOPENING", sizeof(buf));
4178 	flags = vp->v_iflag & ~(VI_TEXT_REF | VI_MOUNT | VI_DOINGINACT |
4179 	    VI_OWEINACT | VI_DEFINACT | VI_FOPENING);
4180 	if (flags != 0) {
4181 		snprintf(buf2, sizeof(buf2), "|VI(0x%lx)", flags);
4182 		strlcat(buf, buf2, sizeof(buf));
4183 	}
4184 	if (vp->v_mflag & VMP_LAZYLIST)
4185 		strlcat(buf, "|VMP_LAZYLIST", sizeof(buf));
4186 	flags = vp->v_mflag & ~(VMP_LAZYLIST);
4187 	if (flags != 0) {
4188 		snprintf(buf2, sizeof(buf2), "|VMP(0x%lx)", flags);
4189 		strlcat(buf, buf2, sizeof(buf));
4190 	}
4191 	printf("    flags (%s)", buf + 1);
4192 	if (mtx_owned(VI_MTX(vp)))
4193 		printf(" VI_LOCKed");
4194 	printf("\n");
4195 	if (vp->v_object != NULL)
4196 		printf("    v_object %p ref %d pages %d "
4197 		    "cleanbuf %d dirtybuf %d\n",
4198 		    vp->v_object, vp->v_object->ref_count,
4199 		    vp->v_object->resident_page_count,
4200 		    vp->v_bufobj.bo_clean.bv_cnt,
4201 		    vp->v_bufobj.bo_dirty.bv_cnt);
4202 	printf("    ");
4203 	lockmgr_printinfo(vp->v_vnlock);
4204 	if (vp->v_data != NULL)
4205 		VOP_PRINT(vp);
4206 }
4207 
4208 #ifdef DDB
4209 /*
4210  * List all of the locked vnodes in the system.
4211  * Called when debugging the kernel.
4212  */
4213 DB_SHOW_COMMAND(lockedvnods, lockedvnodes)
4214 {
4215 	struct mount *mp;
4216 	struct vnode *vp;
4217 
4218 	/*
4219 	 * Note: because this is DDB, we can't obey the locking semantics
4220 	 * for these structures, which means we could catch an inconsistent
4221 	 * state and dereference a nasty pointer.  Not much to be done
4222 	 * about that.
4223 	 */
4224 	db_printf("Locked vnodes\n");
4225 	TAILQ_FOREACH(mp, &mountlist, mnt_list) {
4226 		TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
4227 			if (vp->v_type != VMARKER && VOP_ISLOCKED(vp))
4228 				vn_printf(vp, "vnode ");
4229 		}
4230 	}
4231 }
4232 
4233 /*
4234  * Show details about the given vnode.
4235  */
4236 DB_SHOW_COMMAND(vnode, db_show_vnode)
4237 {
4238 	struct vnode *vp;
4239 
4240 	if (!have_addr)
4241 		return;
4242 	vp = (struct vnode *)addr;
4243 	vn_printf(vp, "vnode ");
4244 }
4245 
4246 /*
4247  * Show details about the given mount point.
4248  */
4249 DB_SHOW_COMMAND(mount, db_show_mount)
4250 {
4251 	struct mount *mp;
4252 	struct vfsopt *opt;
4253 	struct statfs *sp;
4254 	struct vnode *vp;
4255 	char buf[512];
4256 	uint64_t mflags;
4257 	u_int flags;
4258 
4259 	if (!have_addr) {
4260 		/* No address given, print short info about all mount points. */
4261 		TAILQ_FOREACH(mp, &mountlist, mnt_list) {
4262 			db_printf("%p %s on %s (%s)\n", mp,
4263 			    mp->mnt_stat.f_mntfromname,
4264 			    mp->mnt_stat.f_mntonname,
4265 			    mp->mnt_stat.f_fstypename);
4266 			if (db_pager_quit)
4267 				break;
4268 		}
4269 		db_printf("\nMore info: show mount <addr>\n");
4270 		return;
4271 	}
4272 
4273 	mp = (struct mount *)addr;
4274 	db_printf("%p %s on %s (%s)\n", mp, mp->mnt_stat.f_mntfromname,
4275 	    mp->mnt_stat.f_mntonname, mp->mnt_stat.f_fstypename);
4276 
4277 	buf[0] = '\0';
4278 	mflags = mp->mnt_flag;
4279 #define	MNT_FLAG(flag)	do {						\
4280 	if (mflags & (flag)) {						\
4281 		if (buf[0] != '\0')					\
4282 			strlcat(buf, ", ", sizeof(buf));		\
4283 		strlcat(buf, (#flag) + 4, sizeof(buf));			\
4284 		mflags &= ~(flag);					\
4285 	}								\
4286 } while (0)
4287 	MNT_FLAG(MNT_RDONLY);
4288 	MNT_FLAG(MNT_SYNCHRONOUS);
4289 	MNT_FLAG(MNT_NOEXEC);
4290 	MNT_FLAG(MNT_NOSUID);
4291 	MNT_FLAG(MNT_NFS4ACLS);
4292 	MNT_FLAG(MNT_UNION);
4293 	MNT_FLAG(MNT_ASYNC);
4294 	MNT_FLAG(MNT_SUIDDIR);
4295 	MNT_FLAG(MNT_SOFTDEP);
4296 	MNT_FLAG(MNT_NOSYMFOLLOW);
4297 	MNT_FLAG(MNT_GJOURNAL);
4298 	MNT_FLAG(MNT_MULTILABEL);
4299 	MNT_FLAG(MNT_ACLS);
4300 	MNT_FLAG(MNT_NOATIME);
4301 	MNT_FLAG(MNT_NOCLUSTERR);
4302 	MNT_FLAG(MNT_NOCLUSTERW);
4303 	MNT_FLAG(MNT_SUJ);
4304 	MNT_FLAG(MNT_EXRDONLY);
4305 	MNT_FLAG(MNT_EXPORTED);
4306 	MNT_FLAG(MNT_DEFEXPORTED);
4307 	MNT_FLAG(MNT_EXPORTANON);
4308 	MNT_FLAG(MNT_EXKERB);
4309 	MNT_FLAG(MNT_EXPUBLIC);
4310 	MNT_FLAG(MNT_LOCAL);
4311 	MNT_FLAG(MNT_QUOTA);
4312 	MNT_FLAG(MNT_ROOTFS);
4313 	MNT_FLAG(MNT_USER);
4314 	MNT_FLAG(MNT_IGNORE);
4315 	MNT_FLAG(MNT_UPDATE);
4316 	MNT_FLAG(MNT_DELEXPORT);
4317 	MNT_FLAG(MNT_RELOAD);
4318 	MNT_FLAG(MNT_FORCE);
4319 	MNT_FLAG(MNT_SNAPSHOT);
4320 	MNT_FLAG(MNT_BYFSID);
4321 #undef MNT_FLAG
4322 	if (mflags != 0) {
4323 		if (buf[0] != '\0')
4324 			strlcat(buf, ", ", sizeof(buf));
4325 		snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
4326 		    "0x%016jx", mflags);
4327 	}
4328 	db_printf("    mnt_flag = %s\n", buf);
4329 
4330 	buf[0] = '\0';
4331 	flags = mp->mnt_kern_flag;
4332 #define	MNT_KERN_FLAG(flag)	do {					\
4333 	if (flags & (flag)) {						\
4334 		if (buf[0] != '\0')					\
4335 			strlcat(buf, ", ", sizeof(buf));		\
4336 		strlcat(buf, (#flag) + 5, sizeof(buf));			\
4337 		flags &= ~(flag);					\
4338 	}								\
4339 } while (0)
4340 	MNT_KERN_FLAG(MNTK_UNMOUNTF);
4341 	MNT_KERN_FLAG(MNTK_ASYNC);
4342 	MNT_KERN_FLAG(MNTK_SOFTDEP);
4343 	MNT_KERN_FLAG(MNTK_DRAINING);
4344 	MNT_KERN_FLAG(MNTK_REFEXPIRE);
4345 	MNT_KERN_FLAG(MNTK_EXTENDED_SHARED);
4346 	MNT_KERN_FLAG(MNTK_SHARED_WRITES);
4347 	MNT_KERN_FLAG(MNTK_NO_IOPF);
4348 	MNT_KERN_FLAG(MNTK_VGONE_UPPER);
4349 	MNT_KERN_FLAG(MNTK_VGONE_WAITER);
4350 	MNT_KERN_FLAG(MNTK_LOOKUP_EXCL_DOTDOT);
4351 	MNT_KERN_FLAG(MNTK_MARKER);
4352 	MNT_KERN_FLAG(MNTK_USES_BCACHE);
4353 	MNT_KERN_FLAG(MNTK_FPLOOKUP);
4354 	MNT_KERN_FLAG(MNTK_NOASYNC);
4355 	MNT_KERN_FLAG(MNTK_UNMOUNT);
4356 	MNT_KERN_FLAG(MNTK_MWAIT);
4357 	MNT_KERN_FLAG(MNTK_SUSPEND);
4358 	MNT_KERN_FLAG(MNTK_SUSPEND2);
4359 	MNT_KERN_FLAG(MNTK_SUSPENDED);
4360 	MNT_KERN_FLAG(MNTK_LOOKUP_SHARED);
4361 	MNT_KERN_FLAG(MNTK_NOKNOTE);
4362 #undef MNT_KERN_FLAG
4363 	if (flags != 0) {
4364 		if (buf[0] != '\0')
4365 			strlcat(buf, ", ", sizeof(buf));
4366 		snprintf(buf + strlen(buf), sizeof(buf) - strlen(buf),
4367 		    "0x%08x", flags);
4368 	}
4369 	db_printf("    mnt_kern_flag = %s\n", buf);
4370 
4371 	db_printf("    mnt_opt = ");
4372 	opt = TAILQ_FIRST(mp->mnt_opt);
4373 	if (opt != NULL) {
4374 		db_printf("%s", opt->name);
4375 		opt = TAILQ_NEXT(opt, link);
4376 		while (opt != NULL) {
4377 			db_printf(", %s", opt->name);
4378 			opt = TAILQ_NEXT(opt, link);
4379 		}
4380 	}
4381 	db_printf("\n");
4382 
4383 	sp = &mp->mnt_stat;
4384 	db_printf("    mnt_stat = { version=%u type=%u flags=0x%016jx "
4385 	    "bsize=%ju iosize=%ju blocks=%ju bfree=%ju bavail=%jd files=%ju "
4386 	    "ffree=%jd syncwrites=%ju asyncwrites=%ju syncreads=%ju "
4387 	    "asyncreads=%ju namemax=%u owner=%u fsid=[%d, %d] }\n",
4388 	    (u_int)sp->f_version, (u_int)sp->f_type, (uintmax_t)sp->f_flags,
4389 	    (uintmax_t)sp->f_bsize, (uintmax_t)sp->f_iosize,
4390 	    (uintmax_t)sp->f_blocks, (uintmax_t)sp->f_bfree,
4391 	    (intmax_t)sp->f_bavail, (uintmax_t)sp->f_files,
4392 	    (intmax_t)sp->f_ffree, (uintmax_t)sp->f_syncwrites,
4393 	    (uintmax_t)sp->f_asyncwrites, (uintmax_t)sp->f_syncreads,
4394 	    (uintmax_t)sp->f_asyncreads, (u_int)sp->f_namemax,
4395 	    (u_int)sp->f_owner, (int)sp->f_fsid.val[0], (int)sp->f_fsid.val[1]);
4396 
4397 	db_printf("    mnt_cred = { uid=%u ruid=%u",
4398 	    (u_int)mp->mnt_cred->cr_uid, (u_int)mp->mnt_cred->cr_ruid);
4399 	if (jailed(mp->mnt_cred))
4400 		db_printf(", jail=%d", mp->mnt_cred->cr_prison->pr_id);
4401 	db_printf(" }\n");
4402 	db_printf("    mnt_ref = %d (with %d in the struct)\n",
4403 	    vfs_mount_fetch_counter(mp, MNT_COUNT_REF), mp->mnt_ref);
4404 	db_printf("    mnt_gen = %d\n", mp->mnt_gen);
4405 	db_printf("    mnt_nvnodelistsize = %d\n", mp->mnt_nvnodelistsize);
4406 	db_printf("    mnt_lazyvnodelistsize = %d\n",
4407 	    mp->mnt_lazyvnodelistsize);
4408 	db_printf("    mnt_writeopcount = %d (with %d in the struct)\n",
4409 	    vfs_mount_fetch_counter(mp, MNT_COUNT_WRITEOPCOUNT), mp->mnt_writeopcount);
4410 	db_printf("    mnt_maxsymlinklen = %d\n", mp->mnt_maxsymlinklen);
4411 	db_printf("    mnt_iosize_max = %d\n", mp->mnt_iosize_max);
4412 	db_printf("    mnt_hashseed = %u\n", mp->mnt_hashseed);
4413 	db_printf("    mnt_lockref = %d (with %d in the struct)\n",
4414 	    vfs_mount_fetch_counter(mp, MNT_COUNT_LOCKREF), mp->mnt_lockref);
4415 	db_printf("    mnt_secondary_writes = %d\n", mp->mnt_secondary_writes);
4416 	db_printf("    mnt_secondary_accwrites = %d\n",
4417 	    mp->mnt_secondary_accwrites);
4418 	db_printf("    mnt_gjprovider = %s\n",
4419 	    mp->mnt_gjprovider != NULL ? mp->mnt_gjprovider : "NULL");
4420 	db_printf("    mnt_vfs_ops = %d\n", mp->mnt_vfs_ops);
4421 
4422 	db_printf("\n\nList of active vnodes\n");
4423 	TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
4424 		if (vp->v_type != VMARKER && vp->v_holdcnt > 0) {
4425 			vn_printf(vp, "vnode ");
4426 			if (db_pager_quit)
4427 				break;
4428 		}
4429 	}
4430 	db_printf("\n\nList of inactive vnodes\n");
4431 	TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
4432 		if (vp->v_type != VMARKER && vp->v_holdcnt == 0) {
4433 			vn_printf(vp, "vnode ");
4434 			if (db_pager_quit)
4435 				break;
4436 		}
4437 	}
4438 }
4439 #endif	/* DDB */
4440 
4441 /*
4442  * Fill in a struct xvfsconf based on a struct vfsconf.
4443  */
4444 static int
4445 vfsconf2x(struct sysctl_req *req, struct vfsconf *vfsp)
4446 {
4447 	struct xvfsconf xvfsp;
4448 
4449 	bzero(&xvfsp, sizeof(xvfsp));
4450 	strcpy(xvfsp.vfc_name, vfsp->vfc_name);
4451 	xvfsp.vfc_typenum = vfsp->vfc_typenum;
4452 	xvfsp.vfc_refcount = vfsp->vfc_refcount;
4453 	xvfsp.vfc_flags = vfsp->vfc_flags;
4454 	/*
4455 	 * These are unused in userland, we keep them
4456 	 * to not break binary compatibility.
4457 	 */
4458 	xvfsp.vfc_vfsops = NULL;
4459 	xvfsp.vfc_next = NULL;
4460 	return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
4461 }
4462 
4463 #ifdef COMPAT_FREEBSD32
4464 struct xvfsconf32 {
4465 	uint32_t	vfc_vfsops;
4466 	char		vfc_name[MFSNAMELEN];
4467 	int32_t		vfc_typenum;
4468 	int32_t		vfc_refcount;
4469 	int32_t		vfc_flags;
4470 	uint32_t	vfc_next;
4471 };
4472 
4473 static int
4474 vfsconf2x32(struct sysctl_req *req, struct vfsconf *vfsp)
4475 {
4476 	struct xvfsconf32 xvfsp;
4477 
4478 	bzero(&xvfsp, sizeof(xvfsp));
4479 	strcpy(xvfsp.vfc_name, vfsp->vfc_name);
4480 	xvfsp.vfc_typenum = vfsp->vfc_typenum;
4481 	xvfsp.vfc_refcount = vfsp->vfc_refcount;
4482 	xvfsp.vfc_flags = vfsp->vfc_flags;
4483 	return (SYSCTL_OUT(req, &xvfsp, sizeof(xvfsp)));
4484 }
4485 #endif
4486 
4487 /*
4488  * Top level filesystem related information gathering.
4489  */
4490 static int
4491 sysctl_vfs_conflist(SYSCTL_HANDLER_ARGS)
4492 {
4493 	struct vfsconf *vfsp;
4494 	int error;
4495 
4496 	error = 0;
4497 	vfsconf_slock();
4498 	TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
4499 #ifdef COMPAT_FREEBSD32
4500 		if (req->flags & SCTL_MASK32)
4501 			error = vfsconf2x32(req, vfsp);
4502 		else
4503 #endif
4504 			error = vfsconf2x(req, vfsp);
4505 		if (error)
4506 			break;
4507 	}
4508 	vfsconf_sunlock();
4509 	return (error);
4510 }
4511 
4512 SYSCTL_PROC(_vfs, OID_AUTO, conflist, CTLTYPE_OPAQUE | CTLFLAG_RD |
4513     CTLFLAG_MPSAFE, NULL, 0, sysctl_vfs_conflist,
4514     "S,xvfsconf", "List of all configured filesystems");
4515 
4516 #ifndef BURN_BRIDGES
4517 static int	sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS);
4518 
4519 static int
4520 vfs_sysctl(SYSCTL_HANDLER_ARGS)
4521 {
4522 	int *name = (int *)arg1 - 1;	/* XXX */
4523 	u_int namelen = arg2 + 1;	/* XXX */
4524 	struct vfsconf *vfsp;
4525 
4526 	log(LOG_WARNING, "userland calling deprecated sysctl, "
4527 	    "please rebuild world\n");
4528 
4529 #if 1 || defined(COMPAT_PRELITE2)
4530 	/* Resolve ambiguity between VFS_VFSCONF and VFS_GENERIC. */
4531 	if (namelen == 1)
4532 		return (sysctl_ovfs_conf(oidp, arg1, arg2, req));
4533 #endif
4534 
4535 	switch (name[1]) {
4536 	case VFS_MAXTYPENUM:
4537 		if (namelen != 2)
4538 			return (ENOTDIR);
4539 		return (SYSCTL_OUT(req, &maxvfsconf, sizeof(int)));
4540 	case VFS_CONF:
4541 		if (namelen != 3)
4542 			return (ENOTDIR);	/* overloaded */
4543 		vfsconf_slock();
4544 		TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
4545 			if (vfsp->vfc_typenum == name[2])
4546 				break;
4547 		}
4548 		vfsconf_sunlock();
4549 		if (vfsp == NULL)
4550 			return (EOPNOTSUPP);
4551 #ifdef COMPAT_FREEBSD32
4552 		if (req->flags & SCTL_MASK32)
4553 			return (vfsconf2x32(req, vfsp));
4554 		else
4555 #endif
4556 			return (vfsconf2x(req, vfsp));
4557 	}
4558 	return (EOPNOTSUPP);
4559 }
4560 
4561 static SYSCTL_NODE(_vfs, VFS_GENERIC, generic, CTLFLAG_RD | CTLFLAG_SKIP |
4562     CTLFLAG_MPSAFE, vfs_sysctl,
4563     "Generic filesystem");
4564 
4565 #if 1 || defined(COMPAT_PRELITE2)
4566 
4567 static int
4568 sysctl_ovfs_conf(SYSCTL_HANDLER_ARGS)
4569 {
4570 	int error;
4571 	struct vfsconf *vfsp;
4572 	struct ovfsconf ovfs;
4573 
4574 	vfsconf_slock();
4575 	TAILQ_FOREACH(vfsp, &vfsconf, vfc_list) {
4576 		bzero(&ovfs, sizeof(ovfs));
4577 		ovfs.vfc_vfsops = vfsp->vfc_vfsops;	/* XXX used as flag */
4578 		strcpy(ovfs.vfc_name, vfsp->vfc_name);
4579 		ovfs.vfc_index = vfsp->vfc_typenum;
4580 		ovfs.vfc_refcount = vfsp->vfc_refcount;
4581 		ovfs.vfc_flags = vfsp->vfc_flags;
4582 		error = SYSCTL_OUT(req, &ovfs, sizeof ovfs);
4583 		if (error != 0) {
4584 			vfsconf_sunlock();
4585 			return (error);
4586 		}
4587 	}
4588 	vfsconf_sunlock();
4589 	return (0);
4590 }
4591 
4592 #endif /* 1 || COMPAT_PRELITE2 */
4593 #endif /* !BURN_BRIDGES */
4594 
4595 #define KINFO_VNODESLOP		10
4596 #ifdef notyet
4597 /*
4598  * Dump vnode list (via sysctl).
4599  */
4600 /* ARGSUSED */
4601 static int
4602 sysctl_vnode(SYSCTL_HANDLER_ARGS)
4603 {
4604 	struct xvnode *xvn;
4605 	struct mount *mp;
4606 	struct vnode *vp;
4607 	int error, len, n;
4608 
4609 	/*
4610 	 * Stale numvnodes access is not fatal here.
4611 	 */
4612 	req->lock = 0;
4613 	len = (numvnodes + KINFO_VNODESLOP) * sizeof *xvn;
4614 	if (!req->oldptr)
4615 		/* Make an estimate */
4616 		return (SYSCTL_OUT(req, 0, len));
4617 
4618 	error = sysctl_wire_old_buffer(req, 0);
4619 	if (error != 0)
4620 		return (error);
4621 	xvn = malloc(len, M_TEMP, M_ZERO | M_WAITOK);
4622 	n = 0;
4623 	mtx_lock(&mountlist_mtx);
4624 	TAILQ_FOREACH(mp, &mountlist, mnt_list) {
4625 		if (vfs_busy(mp, MBF_NOWAIT | MBF_MNTLSTLOCK))
4626 			continue;
4627 		MNT_ILOCK(mp);
4628 		TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
4629 			if (n == len)
4630 				break;
4631 			vref(vp);
4632 			xvn[n].xv_size = sizeof *xvn;
4633 			xvn[n].xv_vnode = vp;
4634 			xvn[n].xv_id = 0;	/* XXX compat */
4635 #define XV_COPY(field) xvn[n].xv_##field = vp->v_##field
4636 			XV_COPY(usecount);
4637 			XV_COPY(writecount);
4638 			XV_COPY(holdcnt);
4639 			XV_COPY(mount);
4640 			XV_COPY(numoutput);
4641 			XV_COPY(type);
4642 #undef XV_COPY
4643 			xvn[n].xv_flag = vp->v_vflag;
4644 
4645 			switch (vp->v_type) {
4646 			case VREG:
4647 			case VDIR:
4648 			case VLNK:
4649 				break;
4650 			case VBLK:
4651 			case VCHR:
4652 				if (vp->v_rdev == NULL) {
4653 					vrele(vp);
4654 					continue;
4655 				}
4656 				xvn[n].xv_dev = dev2udev(vp->v_rdev);
4657 				break;
4658 			case VSOCK:
4659 				xvn[n].xv_socket = vp->v_socket;
4660 				break;
4661 			case VFIFO:
4662 				xvn[n].xv_fifo = vp->v_fifoinfo;
4663 				break;
4664 			case VNON:
4665 			case VBAD:
4666 			default:
4667 				/* shouldn't happen? */
4668 				vrele(vp);
4669 				continue;
4670 			}
4671 			vrele(vp);
4672 			++n;
4673 		}
4674 		MNT_IUNLOCK(mp);
4675 		mtx_lock(&mountlist_mtx);
4676 		vfs_unbusy(mp);
4677 		if (n == len)
4678 			break;
4679 	}
4680 	mtx_unlock(&mountlist_mtx);
4681 
4682 	error = SYSCTL_OUT(req, xvn, n * sizeof *xvn);
4683 	free(xvn, M_TEMP);
4684 	return (error);
4685 }
4686 
4687 SYSCTL_PROC(_kern, KERN_VNODE, vnode, CTLTYPE_OPAQUE | CTLFLAG_RD |
4688     CTLFLAG_MPSAFE, 0, 0, sysctl_vnode, "S,xvnode",
4689     "");
4690 #endif
4691 
4692 static void
4693 unmount_or_warn(struct mount *mp)
4694 {
4695 	int error;
4696 
4697 	error = dounmount(mp, MNT_FORCE, curthread);
4698 	if (error != 0) {
4699 		printf("unmount of %s failed (", mp->mnt_stat.f_mntonname);
4700 		if (error == EBUSY)
4701 			printf("BUSY)\n");
4702 		else
4703 			printf("%d)\n", error);
4704 	}
4705 }
4706 
4707 /*
4708  * Unmount all filesystems. The list is traversed in reverse order
4709  * of mounting to avoid dependencies.
4710  */
4711 void
4712 vfs_unmountall(void)
4713 {
4714 	struct mount *mp, *tmp;
4715 
4716 	CTR1(KTR_VFS, "%s: unmounting all filesystems", __func__);
4717 
4718 	/*
4719 	 * Since this only runs when rebooting, it is not interlocked.
4720 	 */
4721 	TAILQ_FOREACH_REVERSE_SAFE(mp, &mountlist, mntlist, mnt_list, tmp) {
4722 		vfs_ref(mp);
4723 
4724 		/*
4725 		 * Forcibly unmounting "/dev" before "/" would prevent clean
4726 		 * unmount of the latter.
4727 		 */
4728 		if (mp == rootdevmp)
4729 			continue;
4730 
4731 		unmount_or_warn(mp);
4732 	}
4733 
4734 	if (rootdevmp != NULL)
4735 		unmount_or_warn(rootdevmp);
4736 }
4737 
4738 static void
4739 vfs_deferred_inactive(struct vnode *vp, int lkflags)
4740 {
4741 
4742 	ASSERT_VI_LOCKED(vp, __func__);
4743 	VNASSERT((vp->v_iflag & VI_DEFINACT) == 0, vp, ("VI_DEFINACT still set"));
4744 	if ((vp->v_iflag & VI_OWEINACT) == 0) {
4745 		vdropl(vp);
4746 		return;
4747 	}
4748 	if (vn_lock(vp, lkflags) == 0) {
4749 		VI_LOCK(vp);
4750 		vinactive(vp);
4751 		VOP_UNLOCK(vp);
4752 		vdropl(vp);
4753 		return;
4754 	}
4755 	vdefer_inactive_unlocked(vp);
4756 }
4757 
4758 static int
4759 vfs_periodic_inactive_filter(struct vnode *vp, void *arg)
4760 {
4761 
4762 	return (vp->v_iflag & VI_DEFINACT);
4763 }
4764 
4765 static void __noinline
4766 vfs_periodic_inactive(struct mount *mp, int flags)
4767 {
4768 	struct vnode *vp, *mvp;
4769 	int lkflags;
4770 
4771 	lkflags = LK_EXCLUSIVE | LK_INTERLOCK;
4772 	if (flags != MNT_WAIT)
4773 		lkflags |= LK_NOWAIT;
4774 
4775 	MNT_VNODE_FOREACH_LAZY(vp, mp, mvp, vfs_periodic_inactive_filter, NULL) {
4776 		if ((vp->v_iflag & VI_DEFINACT) == 0) {
4777 			VI_UNLOCK(vp);
4778 			continue;
4779 		}
4780 		vp->v_iflag &= ~VI_DEFINACT;
4781 		vfs_deferred_inactive(vp, lkflags);
4782 	}
4783 }
4784 
4785 static inline bool
4786 vfs_want_msync(struct vnode *vp)
4787 {
4788 	struct vm_object *obj;
4789 
4790 	/*
4791 	 * This test may be performed without any locks held.
4792 	 * We rely on vm_object's type stability.
4793 	 */
4794 	if (vp->v_vflag & VV_NOSYNC)
4795 		return (false);
4796 	obj = vp->v_object;
4797 	return (obj != NULL && vm_object_mightbedirty(obj));
4798 }
4799 
4800 static int
4801 vfs_periodic_msync_inactive_filter(struct vnode *vp, void *arg __unused)
4802 {
4803 
4804 	if (vp->v_vflag & VV_NOSYNC)
4805 		return (false);
4806 	if (vp->v_iflag & VI_DEFINACT)
4807 		return (true);
4808 	return (vfs_want_msync(vp));
4809 }
4810 
4811 static void __noinline
4812 vfs_periodic_msync_inactive(struct mount *mp, int flags)
4813 {
4814 	struct vnode *vp, *mvp;
4815 	struct vm_object *obj;
4816 	int lkflags, objflags;
4817 	bool seen_defer;
4818 
4819 	lkflags = LK_EXCLUSIVE | LK_INTERLOCK;
4820 	if (flags != MNT_WAIT) {
4821 		lkflags |= LK_NOWAIT;
4822 		objflags = OBJPC_NOSYNC;
4823 	} else {
4824 		objflags = OBJPC_SYNC;
4825 	}
4826 
4827 	MNT_VNODE_FOREACH_LAZY(vp, mp, mvp, vfs_periodic_msync_inactive_filter, NULL) {
4828 		seen_defer = false;
4829 		if (vp->v_iflag & VI_DEFINACT) {
4830 			vp->v_iflag &= ~VI_DEFINACT;
4831 			seen_defer = true;
4832 		}
4833 		if (!vfs_want_msync(vp)) {
4834 			if (seen_defer)
4835 				vfs_deferred_inactive(vp, lkflags);
4836 			else
4837 				VI_UNLOCK(vp);
4838 			continue;
4839 		}
4840 		if (vget(vp, lkflags) == 0) {
4841 			obj = vp->v_object;
4842 			if (obj != NULL && (vp->v_vflag & VV_NOSYNC) == 0) {
4843 				VM_OBJECT_WLOCK(obj);
4844 				vm_object_page_clean(obj, 0, 0, objflags);
4845 				VM_OBJECT_WUNLOCK(obj);
4846 			}
4847 			vput(vp);
4848 			if (seen_defer)
4849 				vdrop(vp);
4850 		} else {
4851 			if (seen_defer)
4852 				vdefer_inactive_unlocked(vp);
4853 		}
4854 	}
4855 }
4856 
4857 void
4858 vfs_periodic(struct mount *mp, int flags)
4859 {
4860 
4861 	CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
4862 
4863 	if ((mp->mnt_kern_flag & MNTK_NOMSYNC) != 0)
4864 		vfs_periodic_inactive(mp, flags);
4865 	else
4866 		vfs_periodic_msync_inactive(mp, flags);
4867 }
4868 
4869 static void
4870 destroy_vpollinfo_free(struct vpollinfo *vi)
4871 {
4872 
4873 	knlist_destroy(&vi->vpi_selinfo.si_note);
4874 	mtx_destroy(&vi->vpi_lock);
4875 	free(vi, M_VNODEPOLL);
4876 }
4877 
4878 static void
4879 destroy_vpollinfo(struct vpollinfo *vi)
4880 {
4881 
4882 	knlist_clear(&vi->vpi_selinfo.si_note, 1);
4883 	seldrain(&vi->vpi_selinfo);
4884 	destroy_vpollinfo_free(vi);
4885 }
4886 
4887 /*
4888  * Initialize per-vnode helper structure to hold poll-related state.
4889  */
4890 void
4891 v_addpollinfo(struct vnode *vp)
4892 {
4893 	struct vpollinfo *vi;
4894 
4895 	if (vp->v_pollinfo != NULL)
4896 		return;
4897 	vi = malloc(sizeof(*vi), M_VNODEPOLL, M_WAITOK | M_ZERO);
4898 	mtx_init(&vi->vpi_lock, "vnode pollinfo", NULL, MTX_DEF);
4899 	knlist_init(&vi->vpi_selinfo.si_note, vp, vfs_knllock,
4900 	    vfs_knlunlock, vfs_knl_assert_lock);
4901 	VI_LOCK(vp);
4902 	if (vp->v_pollinfo != NULL) {
4903 		VI_UNLOCK(vp);
4904 		destroy_vpollinfo_free(vi);
4905 		return;
4906 	}
4907 	vp->v_pollinfo = vi;
4908 	VI_UNLOCK(vp);
4909 }
4910 
4911 /*
4912  * Record a process's interest in events which might happen to
4913  * a vnode.  Because poll uses the historic select-style interface
4914  * internally, this routine serves as both the ``check for any
4915  * pending events'' and the ``record my interest in future events''
4916  * functions.  (These are done together, while the lock is held,
4917  * to avoid race conditions.)
4918  */
4919 int
4920 vn_pollrecord(struct vnode *vp, struct thread *td, int events)
4921 {
4922 
4923 	v_addpollinfo(vp);
4924 	mtx_lock(&vp->v_pollinfo->vpi_lock);
4925 	if (vp->v_pollinfo->vpi_revents & events) {
4926 		/*
4927 		 * This leaves events we are not interested
4928 		 * in available for the other process which
4929 		 * which presumably had requested them
4930 		 * (otherwise they would never have been
4931 		 * recorded).
4932 		 */
4933 		events &= vp->v_pollinfo->vpi_revents;
4934 		vp->v_pollinfo->vpi_revents &= ~events;
4935 
4936 		mtx_unlock(&vp->v_pollinfo->vpi_lock);
4937 		return (events);
4938 	}
4939 	vp->v_pollinfo->vpi_events |= events;
4940 	selrecord(td, &vp->v_pollinfo->vpi_selinfo);
4941 	mtx_unlock(&vp->v_pollinfo->vpi_lock);
4942 	return (0);
4943 }
4944 
4945 /*
4946  * Routine to create and manage a filesystem syncer vnode.
4947  */
4948 #define sync_close ((int (*)(struct  vop_close_args *))nullop)
4949 static int	sync_fsync(struct  vop_fsync_args *);
4950 static int	sync_inactive(struct  vop_inactive_args *);
4951 static int	sync_reclaim(struct  vop_reclaim_args *);
4952 
4953 static struct vop_vector sync_vnodeops = {
4954 	.vop_bypass =	VOP_EOPNOTSUPP,
4955 	.vop_close =	sync_close,		/* close */
4956 	.vop_fsync =	sync_fsync,		/* fsync */
4957 	.vop_inactive =	sync_inactive,	/* inactive */
4958 	.vop_need_inactive = vop_stdneed_inactive, /* need_inactive */
4959 	.vop_reclaim =	sync_reclaim,	/* reclaim */
4960 	.vop_lock1 =	vop_stdlock,	/* lock */
4961 	.vop_unlock =	vop_stdunlock,	/* unlock */
4962 	.vop_islocked =	vop_stdislocked,	/* islocked */
4963 };
4964 VFS_VOP_VECTOR_REGISTER(sync_vnodeops);
4965 
4966 /*
4967  * Create a new filesystem syncer vnode for the specified mount point.
4968  */
4969 void
4970 vfs_allocate_syncvnode(struct mount *mp)
4971 {
4972 	struct vnode *vp;
4973 	struct bufobj *bo;
4974 	static long start, incr, next;
4975 	int error;
4976 
4977 	/* Allocate a new vnode */
4978 	error = getnewvnode("syncer", mp, &sync_vnodeops, &vp);
4979 	if (error != 0)
4980 		panic("vfs_allocate_syncvnode: getnewvnode() failed");
4981 	vp->v_type = VNON;
4982 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
4983 	vp->v_vflag |= VV_FORCEINSMQ;
4984 	error = insmntque(vp, mp);
4985 	if (error != 0)
4986 		panic("vfs_allocate_syncvnode: insmntque() failed");
4987 	vp->v_vflag &= ~VV_FORCEINSMQ;
4988 	VOP_UNLOCK(vp);
4989 	/*
4990 	 * Place the vnode onto the syncer worklist. We attempt to
4991 	 * scatter them about on the list so that they will go off
4992 	 * at evenly distributed times even if all the filesystems
4993 	 * are mounted at once.
4994 	 */
4995 	next += incr;
4996 	if (next == 0 || next > syncer_maxdelay) {
4997 		start /= 2;
4998 		incr /= 2;
4999 		if (start == 0) {
5000 			start = syncer_maxdelay / 2;
5001 			incr = syncer_maxdelay;
5002 		}
5003 		next = start;
5004 	}
5005 	bo = &vp->v_bufobj;
5006 	BO_LOCK(bo);
5007 	vn_syncer_add_to_worklist(bo, syncdelay > 0 ? next % syncdelay : 0);
5008 	/* XXX - vn_syncer_add_to_worklist() also grabs and drops sync_mtx. */
5009 	mtx_lock(&sync_mtx);
5010 	sync_vnode_count++;
5011 	if (mp->mnt_syncer == NULL) {
5012 		mp->mnt_syncer = vp;
5013 		vp = NULL;
5014 	}
5015 	mtx_unlock(&sync_mtx);
5016 	BO_UNLOCK(bo);
5017 	if (vp != NULL) {
5018 		vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
5019 		vgone(vp);
5020 		vput(vp);
5021 	}
5022 }
5023 
5024 void
5025 vfs_deallocate_syncvnode(struct mount *mp)
5026 {
5027 	struct vnode *vp;
5028 
5029 	mtx_lock(&sync_mtx);
5030 	vp = mp->mnt_syncer;
5031 	if (vp != NULL)
5032 		mp->mnt_syncer = NULL;
5033 	mtx_unlock(&sync_mtx);
5034 	if (vp != NULL)
5035 		vrele(vp);
5036 }
5037 
5038 /*
5039  * Do a lazy sync of the filesystem.
5040  */
5041 static int
5042 sync_fsync(struct vop_fsync_args *ap)
5043 {
5044 	struct vnode *syncvp = ap->a_vp;
5045 	struct mount *mp = syncvp->v_mount;
5046 	int error, save;
5047 	struct bufobj *bo;
5048 
5049 	/*
5050 	 * We only need to do something if this is a lazy evaluation.
5051 	 */
5052 	if (ap->a_waitfor != MNT_LAZY)
5053 		return (0);
5054 
5055 	/*
5056 	 * Move ourselves to the back of the sync list.
5057 	 */
5058 	bo = &syncvp->v_bufobj;
5059 	BO_LOCK(bo);
5060 	vn_syncer_add_to_worklist(bo, syncdelay);
5061 	BO_UNLOCK(bo);
5062 
5063 	/*
5064 	 * Walk the list of vnodes pushing all that are dirty and
5065 	 * not already on the sync list.
5066 	 */
5067 	if (vfs_busy(mp, MBF_NOWAIT) != 0)
5068 		return (0);
5069 	if (vn_start_write(NULL, &mp, V_NOWAIT) != 0) {
5070 		vfs_unbusy(mp);
5071 		return (0);
5072 	}
5073 	save = curthread_pflags_set(TDP_SYNCIO);
5074 	/*
5075 	 * The filesystem at hand may be idle with free vnodes stored in the
5076 	 * batch.  Return them instead of letting them stay there indefinitely.
5077 	 */
5078 	vfs_periodic(mp, MNT_NOWAIT);
5079 	error = VFS_SYNC(mp, MNT_LAZY);
5080 	curthread_pflags_restore(save);
5081 	vn_finished_write(mp);
5082 	vfs_unbusy(mp);
5083 	return (error);
5084 }
5085 
5086 /*
5087  * The syncer vnode is no referenced.
5088  */
5089 static int
5090 sync_inactive(struct vop_inactive_args *ap)
5091 {
5092 
5093 	vgone(ap->a_vp);
5094 	return (0);
5095 }
5096 
5097 /*
5098  * The syncer vnode is no longer needed and is being decommissioned.
5099  *
5100  * Modifications to the worklist must be protected by sync_mtx.
5101  */
5102 static int
5103 sync_reclaim(struct vop_reclaim_args *ap)
5104 {
5105 	struct vnode *vp = ap->a_vp;
5106 	struct bufobj *bo;
5107 
5108 	bo = &vp->v_bufobj;
5109 	BO_LOCK(bo);
5110 	mtx_lock(&sync_mtx);
5111 	if (vp->v_mount->mnt_syncer == vp)
5112 		vp->v_mount->mnt_syncer = NULL;
5113 	if (bo->bo_flag & BO_ONWORKLST) {
5114 		LIST_REMOVE(bo, bo_synclist);
5115 		syncer_worklist_len--;
5116 		sync_vnode_count--;
5117 		bo->bo_flag &= ~BO_ONWORKLST;
5118 	}
5119 	mtx_unlock(&sync_mtx);
5120 	BO_UNLOCK(bo);
5121 
5122 	return (0);
5123 }
5124 
5125 int
5126 vn_need_pageq_flush(struct vnode *vp)
5127 {
5128 	struct vm_object *obj;
5129 	int need;
5130 
5131 	MPASS(mtx_owned(VI_MTX(vp)));
5132 	need = 0;
5133 	if ((obj = vp->v_object) != NULL && (vp->v_vflag & VV_NOSYNC) == 0 &&
5134 	    vm_object_mightbedirty(obj))
5135 		need = 1;
5136 	return (need);
5137 }
5138 
5139 /*
5140  * Check if vnode represents a disk device
5141  */
5142 bool
5143 vn_isdisk_error(struct vnode *vp, int *errp)
5144 {
5145 	int error;
5146 
5147 	if (vp->v_type != VCHR) {
5148 		error = ENOTBLK;
5149 		goto out;
5150 	}
5151 	error = 0;
5152 	dev_lock();
5153 	if (vp->v_rdev == NULL)
5154 		error = ENXIO;
5155 	else if (vp->v_rdev->si_devsw == NULL)
5156 		error = ENXIO;
5157 	else if (!(vp->v_rdev->si_devsw->d_flags & D_DISK))
5158 		error = ENOTBLK;
5159 	dev_unlock();
5160 out:
5161 	*errp = error;
5162 	return (error == 0);
5163 }
5164 
5165 bool
5166 vn_isdisk(struct vnode *vp)
5167 {
5168 	int error;
5169 
5170 	return (vn_isdisk_error(vp, &error));
5171 }
5172 
5173 /*
5174  * VOP_FPLOOKUP_VEXEC routines are subject to special circumstances, see
5175  * the comment above cache_fplookup for details.
5176  */
5177 int
5178 vaccess_vexec_smr(mode_t file_mode, uid_t file_uid, gid_t file_gid, struct ucred *cred)
5179 {
5180 	int error;
5181 
5182 	VFS_SMR_ASSERT_ENTERED();
5183 
5184 	/* Check the owner. */
5185 	if (cred->cr_uid == file_uid) {
5186 		if (file_mode & S_IXUSR)
5187 			return (0);
5188 		goto out_error;
5189 	}
5190 
5191 	/* Otherwise, check the groups (first match) */
5192 	if (groupmember(file_gid, cred)) {
5193 		if (file_mode & S_IXGRP)
5194 			return (0);
5195 		goto out_error;
5196 	}
5197 
5198 	/* Otherwise, check everyone else. */
5199 	if (file_mode & S_IXOTH)
5200 		return (0);
5201 out_error:
5202 	/*
5203 	 * Permission check failed, but it is possible denial will get overwritten
5204 	 * (e.g., when root is traversing through a 700 directory owned by someone
5205 	 * else).
5206 	 *
5207 	 * vaccess() calls priv_check_cred which in turn can descent into MAC
5208 	 * modules overriding this result. It's quite unclear what semantics
5209 	 * are allowed for them to operate, thus for safety we don't call them
5210 	 * from within the SMR section. This also means if any such modules
5211 	 * are present, we have to let the regular lookup decide.
5212 	 */
5213 	error = priv_check_cred_vfs_lookup_nomac(cred);
5214 	switch (error) {
5215 	case 0:
5216 		return (0);
5217 	case EAGAIN:
5218 		/*
5219 		 * MAC modules present.
5220 		 */
5221 		return (EAGAIN);
5222 	case EPERM:
5223 		return (EACCES);
5224 	default:
5225 		return (error);
5226 	}
5227 }
5228 
5229 /*
5230  * Common filesystem object access control check routine.  Accepts a
5231  * vnode's type, "mode", uid and gid, requested access mode, and credentials.
5232  * Returns 0 on success, or an errno on failure.
5233  */
5234 int
5235 vaccess(enum vtype type, mode_t file_mode, uid_t file_uid, gid_t file_gid,
5236     accmode_t accmode, struct ucred *cred)
5237 {
5238 	accmode_t dac_granted;
5239 	accmode_t priv_granted;
5240 
5241 	KASSERT((accmode & ~(VEXEC | VWRITE | VREAD | VADMIN | VAPPEND)) == 0,
5242 	    ("invalid bit in accmode"));
5243 	KASSERT((accmode & VAPPEND) == 0 || (accmode & VWRITE),
5244 	    ("VAPPEND without VWRITE"));
5245 
5246 	/*
5247 	 * Look for a normal, non-privileged way to access the file/directory
5248 	 * as requested.  If it exists, go with that.
5249 	 */
5250 
5251 	dac_granted = 0;
5252 
5253 	/* Check the owner. */
5254 	if (cred->cr_uid == file_uid) {
5255 		dac_granted |= VADMIN;
5256 		if (file_mode & S_IXUSR)
5257 			dac_granted |= VEXEC;
5258 		if (file_mode & S_IRUSR)
5259 			dac_granted |= VREAD;
5260 		if (file_mode & S_IWUSR)
5261 			dac_granted |= (VWRITE | VAPPEND);
5262 
5263 		if ((accmode & dac_granted) == accmode)
5264 			return (0);
5265 
5266 		goto privcheck;
5267 	}
5268 
5269 	/* Otherwise, check the groups (first match) */
5270 	if (groupmember(file_gid, cred)) {
5271 		if (file_mode & S_IXGRP)
5272 			dac_granted |= VEXEC;
5273 		if (file_mode & S_IRGRP)
5274 			dac_granted |= VREAD;
5275 		if (file_mode & S_IWGRP)
5276 			dac_granted |= (VWRITE | VAPPEND);
5277 
5278 		if ((accmode & dac_granted) == accmode)
5279 			return (0);
5280 
5281 		goto privcheck;
5282 	}
5283 
5284 	/* Otherwise, check everyone else. */
5285 	if (file_mode & S_IXOTH)
5286 		dac_granted |= VEXEC;
5287 	if (file_mode & S_IROTH)
5288 		dac_granted |= VREAD;
5289 	if (file_mode & S_IWOTH)
5290 		dac_granted |= (VWRITE | VAPPEND);
5291 	if ((accmode & dac_granted) == accmode)
5292 		return (0);
5293 
5294 privcheck:
5295 	/*
5296 	 * Build a privilege mask to determine if the set of privileges
5297 	 * satisfies the requirements when combined with the granted mask
5298 	 * from above.  For each privilege, if the privilege is required,
5299 	 * bitwise or the request type onto the priv_granted mask.
5300 	 */
5301 	priv_granted = 0;
5302 
5303 	if (type == VDIR) {
5304 		/*
5305 		 * For directories, use PRIV_VFS_LOOKUP to satisfy VEXEC
5306 		 * requests, instead of PRIV_VFS_EXEC.
5307 		 */
5308 		if ((accmode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
5309 		    !priv_check_cred(cred, PRIV_VFS_LOOKUP))
5310 			priv_granted |= VEXEC;
5311 	} else {
5312 		/*
5313 		 * Ensure that at least one execute bit is on. Otherwise,
5314 		 * a privileged user will always succeed, and we don't want
5315 		 * this to happen unless the file really is executable.
5316 		 */
5317 		if ((accmode & VEXEC) && ((dac_granted & VEXEC) == 0) &&
5318 		    (file_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) != 0 &&
5319 		    !priv_check_cred(cred, PRIV_VFS_EXEC))
5320 			priv_granted |= VEXEC;
5321 	}
5322 
5323 	if ((accmode & VREAD) && ((dac_granted & VREAD) == 0) &&
5324 	    !priv_check_cred(cred, PRIV_VFS_READ))
5325 		priv_granted |= VREAD;
5326 
5327 	if ((accmode & VWRITE) && ((dac_granted & VWRITE) == 0) &&
5328 	    !priv_check_cred(cred, PRIV_VFS_WRITE))
5329 		priv_granted |= (VWRITE | VAPPEND);
5330 
5331 	if ((accmode & VADMIN) && ((dac_granted & VADMIN) == 0) &&
5332 	    !priv_check_cred(cred, PRIV_VFS_ADMIN))
5333 		priv_granted |= VADMIN;
5334 
5335 	if ((accmode & (priv_granted | dac_granted)) == accmode) {
5336 		return (0);
5337 	}
5338 
5339 	return ((accmode & VADMIN) ? EPERM : EACCES);
5340 }
5341 
5342 /*
5343  * Credential check based on process requesting service, and per-attribute
5344  * permissions.
5345  */
5346 int
5347 extattr_check_cred(struct vnode *vp, int attrnamespace, struct ucred *cred,
5348     struct thread *td, accmode_t accmode)
5349 {
5350 
5351 	/*
5352 	 * Kernel-invoked always succeeds.
5353 	 */
5354 	if (cred == NOCRED)
5355 		return (0);
5356 
5357 	/*
5358 	 * Do not allow privileged processes in jail to directly manipulate
5359 	 * system attributes.
5360 	 */
5361 	switch (attrnamespace) {
5362 	case EXTATTR_NAMESPACE_SYSTEM:
5363 		/* Potentially should be: return (EPERM); */
5364 		return (priv_check_cred(cred, PRIV_VFS_EXTATTR_SYSTEM));
5365 	case EXTATTR_NAMESPACE_USER:
5366 		return (VOP_ACCESS(vp, accmode, cred, td));
5367 	default:
5368 		return (EPERM);
5369 	}
5370 }
5371 
5372 #ifdef DEBUG_VFS_LOCKS
5373 /*
5374  * This only exists to suppress warnings from unlocked specfs accesses.  It is
5375  * no longer ok to have an unlocked VFS.
5376  */
5377 #define	IGNORE_LOCK(vp) (KERNEL_PANICKED() || (vp) == NULL ||		\
5378 	(vp)->v_type == VCHR ||	(vp)->v_type == VBAD)
5379 
5380 int vfs_badlock_ddb = 1;	/* Drop into debugger on violation. */
5381 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_ddb, CTLFLAG_RW, &vfs_badlock_ddb, 0,
5382     "Drop into debugger on lock violation");
5383 
5384 int vfs_badlock_mutex = 1;	/* Check for interlock across VOPs. */
5385 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_mutex, CTLFLAG_RW, &vfs_badlock_mutex,
5386     0, "Check for interlock across VOPs");
5387 
5388 int vfs_badlock_print = 1;	/* Print lock violations. */
5389 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_print, CTLFLAG_RW, &vfs_badlock_print,
5390     0, "Print lock violations");
5391 
5392 int vfs_badlock_vnode = 1;	/* Print vnode details on lock violations. */
5393 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_vnode, CTLFLAG_RW, &vfs_badlock_vnode,
5394     0, "Print vnode details on lock violations");
5395 
5396 #ifdef KDB
5397 int vfs_badlock_backtrace = 1;	/* Print backtrace at lock violations. */
5398 SYSCTL_INT(_debug, OID_AUTO, vfs_badlock_backtrace, CTLFLAG_RW,
5399     &vfs_badlock_backtrace, 0, "Print backtrace at lock violations");
5400 #endif
5401 
5402 static void
5403 vfs_badlock(const char *msg, const char *str, struct vnode *vp)
5404 {
5405 
5406 #ifdef KDB
5407 	if (vfs_badlock_backtrace)
5408 		kdb_backtrace();
5409 #endif
5410 	if (vfs_badlock_vnode)
5411 		vn_printf(vp, "vnode ");
5412 	if (vfs_badlock_print)
5413 		printf("%s: %p %s\n", str, (void *)vp, msg);
5414 	if (vfs_badlock_ddb)
5415 		kdb_enter(KDB_WHY_VFSLOCK, "lock violation");
5416 }
5417 
5418 void
5419 assert_vi_locked(struct vnode *vp, const char *str)
5420 {
5421 
5422 	if (vfs_badlock_mutex && !mtx_owned(VI_MTX(vp)))
5423 		vfs_badlock("interlock is not locked but should be", str, vp);
5424 }
5425 
5426 void
5427 assert_vi_unlocked(struct vnode *vp, const char *str)
5428 {
5429 
5430 	if (vfs_badlock_mutex && mtx_owned(VI_MTX(vp)))
5431 		vfs_badlock("interlock is locked but should not be", str, vp);
5432 }
5433 
5434 void
5435 assert_vop_locked(struct vnode *vp, const char *str)
5436 {
5437 	int locked;
5438 
5439 	if (!IGNORE_LOCK(vp)) {
5440 		locked = VOP_ISLOCKED(vp);
5441 		if (locked == 0 || locked == LK_EXCLOTHER)
5442 			vfs_badlock("is not locked but should be", str, vp);
5443 	}
5444 }
5445 
5446 void
5447 assert_vop_unlocked(struct vnode *vp, const char *str)
5448 {
5449 
5450 	if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) == LK_EXCLUSIVE)
5451 		vfs_badlock("is locked but should not be", str, vp);
5452 }
5453 
5454 void
5455 assert_vop_elocked(struct vnode *vp, const char *str)
5456 {
5457 
5458 	if (!IGNORE_LOCK(vp) && VOP_ISLOCKED(vp) != LK_EXCLUSIVE)
5459 		vfs_badlock("is not exclusive locked but should be", str, vp);
5460 }
5461 #endif /* DEBUG_VFS_LOCKS */
5462 
5463 void
5464 vop_rename_fail(struct vop_rename_args *ap)
5465 {
5466 
5467 	if (ap->a_tvp != NULL)
5468 		vput(ap->a_tvp);
5469 	if (ap->a_tdvp == ap->a_tvp)
5470 		vrele(ap->a_tdvp);
5471 	else
5472 		vput(ap->a_tdvp);
5473 	vrele(ap->a_fdvp);
5474 	vrele(ap->a_fvp);
5475 }
5476 
5477 void
5478 vop_rename_pre(void *ap)
5479 {
5480 	struct vop_rename_args *a = ap;
5481 
5482 #ifdef DEBUG_VFS_LOCKS
5483 	if (a->a_tvp)
5484 		ASSERT_VI_UNLOCKED(a->a_tvp, "VOP_RENAME");
5485 	ASSERT_VI_UNLOCKED(a->a_tdvp, "VOP_RENAME");
5486 	ASSERT_VI_UNLOCKED(a->a_fvp, "VOP_RENAME");
5487 	ASSERT_VI_UNLOCKED(a->a_fdvp, "VOP_RENAME");
5488 
5489 	/* Check the source (from). */
5490 	if (a->a_tdvp->v_vnlock != a->a_fdvp->v_vnlock &&
5491 	    (a->a_tvp == NULL || a->a_tvp->v_vnlock != a->a_fdvp->v_vnlock))
5492 		ASSERT_VOP_UNLOCKED(a->a_fdvp, "vop_rename: fdvp locked");
5493 	if (a->a_tvp == NULL || a->a_tvp->v_vnlock != a->a_fvp->v_vnlock)
5494 		ASSERT_VOP_UNLOCKED(a->a_fvp, "vop_rename: fvp locked");
5495 
5496 	/* Check the target. */
5497 	if (a->a_tvp)
5498 		ASSERT_VOP_LOCKED(a->a_tvp, "vop_rename: tvp not locked");
5499 	ASSERT_VOP_LOCKED(a->a_tdvp, "vop_rename: tdvp not locked");
5500 #endif
5501 	/*
5502 	 * It may be tempting to add vn_seqc_write_begin/end calls here and
5503 	 * in vop_rename_post but that's not going to work out since some
5504 	 * filesystems relookup vnodes mid-rename. This is probably a bug.
5505 	 *
5506 	 * For now filesystems are expected to do the relevant calls after they
5507 	 * decide what vnodes to operate on.
5508 	 */
5509 	if (a->a_tdvp != a->a_fdvp)
5510 		vhold(a->a_fdvp);
5511 	if (a->a_tvp != a->a_fvp)
5512 		vhold(a->a_fvp);
5513 	vhold(a->a_tdvp);
5514 	if (a->a_tvp)
5515 		vhold(a->a_tvp);
5516 }
5517 
5518 #ifdef DEBUG_VFS_LOCKS
5519 void
5520 vop_fplookup_vexec_debugpre(void *ap __unused)
5521 {
5522 
5523 	VFS_SMR_ASSERT_ENTERED();
5524 }
5525 
5526 void
5527 vop_fplookup_vexec_debugpost(void *ap __unused, int rc __unused)
5528 {
5529 
5530 	VFS_SMR_ASSERT_ENTERED();
5531 }
5532 
5533 void
5534 vop_fplookup_symlink_debugpre(void *ap __unused)
5535 {
5536 
5537 	VFS_SMR_ASSERT_ENTERED();
5538 }
5539 
5540 void
5541 vop_fplookup_symlink_debugpost(void *ap __unused, int rc __unused)
5542 {
5543 
5544 	VFS_SMR_ASSERT_ENTERED();
5545 }
5546 void
5547 vop_strategy_debugpre(void *ap)
5548 {
5549 	struct vop_strategy_args *a;
5550 	struct buf *bp;
5551 
5552 	a = ap;
5553 	bp = a->a_bp;
5554 
5555 	/*
5556 	 * Cluster ops lock their component buffers but not the IO container.
5557 	 */
5558 	if ((bp->b_flags & B_CLUSTER) != 0)
5559 		return;
5560 
5561 	if (!KERNEL_PANICKED() && !BUF_ISLOCKED(bp)) {
5562 		if (vfs_badlock_print)
5563 			printf(
5564 			    "VOP_STRATEGY: bp is not locked but should be\n");
5565 		if (vfs_badlock_ddb)
5566 			kdb_enter(KDB_WHY_VFSLOCK, "lock violation");
5567 	}
5568 }
5569 
5570 void
5571 vop_lock_debugpre(void *ap)
5572 {
5573 	struct vop_lock1_args *a = ap;
5574 
5575 	if ((a->a_flags & LK_INTERLOCK) == 0)
5576 		ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
5577 	else
5578 		ASSERT_VI_LOCKED(a->a_vp, "VOP_LOCK");
5579 }
5580 
5581 void
5582 vop_lock_debugpost(void *ap, int rc)
5583 {
5584 	struct vop_lock1_args *a = ap;
5585 
5586 	ASSERT_VI_UNLOCKED(a->a_vp, "VOP_LOCK");
5587 	if (rc == 0 && (a->a_flags & LK_EXCLOTHER) == 0)
5588 		ASSERT_VOP_LOCKED(a->a_vp, "VOP_LOCK");
5589 }
5590 
5591 void
5592 vop_unlock_debugpre(void *ap)
5593 {
5594 	struct vop_unlock_args *a = ap;
5595 
5596 	ASSERT_VOP_LOCKED(a->a_vp, "VOP_UNLOCK");
5597 }
5598 
5599 void
5600 vop_need_inactive_debugpre(void *ap)
5601 {
5602 	struct vop_need_inactive_args *a = ap;
5603 
5604 	ASSERT_VI_LOCKED(a->a_vp, "VOP_NEED_INACTIVE");
5605 }
5606 
5607 void
5608 vop_need_inactive_debugpost(void *ap, int rc)
5609 {
5610 	struct vop_need_inactive_args *a = ap;
5611 
5612 	ASSERT_VI_LOCKED(a->a_vp, "VOP_NEED_INACTIVE");
5613 }
5614 #endif
5615 
5616 void
5617 vop_create_pre(void *ap)
5618 {
5619 	struct vop_create_args *a;
5620 	struct vnode *dvp;
5621 
5622 	a = ap;
5623 	dvp = a->a_dvp;
5624 	vn_seqc_write_begin(dvp);
5625 }
5626 
5627 void
5628 vop_create_post(void *ap, int rc)
5629 {
5630 	struct vop_create_args *a;
5631 	struct vnode *dvp;
5632 
5633 	a = ap;
5634 	dvp = a->a_dvp;
5635 	vn_seqc_write_end(dvp);
5636 	if (!rc)
5637 		VFS_KNOTE_LOCKED(dvp, NOTE_WRITE);
5638 }
5639 
5640 void
5641 vop_whiteout_pre(void *ap)
5642 {
5643 	struct vop_whiteout_args *a;
5644 	struct vnode *dvp;
5645 
5646 	a = ap;
5647 	dvp = a->a_dvp;
5648 	vn_seqc_write_begin(dvp);
5649 }
5650 
5651 void
5652 vop_whiteout_post(void *ap, int rc)
5653 {
5654 	struct vop_whiteout_args *a;
5655 	struct vnode *dvp;
5656 
5657 	a = ap;
5658 	dvp = a->a_dvp;
5659 	vn_seqc_write_end(dvp);
5660 }
5661 
5662 void
5663 vop_deleteextattr_pre(void *ap)
5664 {
5665 	struct vop_deleteextattr_args *a;
5666 	struct vnode *vp;
5667 
5668 	a = ap;
5669 	vp = a->a_vp;
5670 	vn_seqc_write_begin(vp);
5671 }
5672 
5673 void
5674 vop_deleteextattr_post(void *ap, int rc)
5675 {
5676 	struct vop_deleteextattr_args *a;
5677 	struct vnode *vp;
5678 
5679 	a = ap;
5680 	vp = a->a_vp;
5681 	vn_seqc_write_end(vp);
5682 	if (!rc)
5683 		VFS_KNOTE_LOCKED(a->a_vp, NOTE_ATTRIB);
5684 }
5685 
5686 void
5687 vop_link_pre(void *ap)
5688 {
5689 	struct vop_link_args *a;
5690 	struct vnode *vp, *tdvp;
5691 
5692 	a = ap;
5693 	vp = a->a_vp;
5694 	tdvp = a->a_tdvp;
5695 	vn_seqc_write_begin(vp);
5696 	vn_seqc_write_begin(tdvp);
5697 }
5698 
5699 void
5700 vop_link_post(void *ap, int rc)
5701 {
5702 	struct vop_link_args *a;
5703 	struct vnode *vp, *tdvp;
5704 
5705 	a = ap;
5706 	vp = a->a_vp;
5707 	tdvp = a->a_tdvp;
5708 	vn_seqc_write_end(vp);
5709 	vn_seqc_write_end(tdvp);
5710 	if (!rc) {
5711 		VFS_KNOTE_LOCKED(vp, NOTE_LINK);
5712 		VFS_KNOTE_LOCKED(tdvp, NOTE_WRITE);
5713 	}
5714 }
5715 
5716 void
5717 vop_mkdir_pre(void *ap)
5718 {
5719 	struct vop_mkdir_args *a;
5720 	struct vnode *dvp;
5721 
5722 	a = ap;
5723 	dvp = a->a_dvp;
5724 	vn_seqc_write_begin(dvp);
5725 }
5726 
5727 void
5728 vop_mkdir_post(void *ap, int rc)
5729 {
5730 	struct vop_mkdir_args *a;
5731 	struct vnode *dvp;
5732 
5733 	a = ap;
5734 	dvp = a->a_dvp;
5735 	vn_seqc_write_end(dvp);
5736 	if (!rc)
5737 		VFS_KNOTE_LOCKED(dvp, NOTE_WRITE | NOTE_LINK);
5738 }
5739 
5740 #ifdef DEBUG_VFS_LOCKS
5741 void
5742 vop_mkdir_debugpost(void *ap, int rc)
5743 {
5744 	struct vop_mkdir_args *a;
5745 
5746 	a = ap;
5747 	if (!rc)
5748 		cache_validate(a->a_dvp, *a->a_vpp, a->a_cnp);
5749 }
5750 #endif
5751 
5752 void
5753 vop_mknod_pre(void *ap)
5754 {
5755 	struct vop_mknod_args *a;
5756 	struct vnode *dvp;
5757 
5758 	a = ap;
5759 	dvp = a->a_dvp;
5760 	vn_seqc_write_begin(dvp);
5761 }
5762 
5763 void
5764 vop_mknod_post(void *ap, int rc)
5765 {
5766 	struct vop_mknod_args *a;
5767 	struct vnode *dvp;
5768 
5769 	a = ap;
5770 	dvp = a->a_dvp;
5771 	vn_seqc_write_end(dvp);
5772 	if (!rc)
5773 		VFS_KNOTE_LOCKED(dvp, NOTE_WRITE);
5774 }
5775 
5776 void
5777 vop_reclaim_post(void *ap, int rc)
5778 {
5779 	struct vop_reclaim_args *a;
5780 	struct vnode *vp;
5781 
5782 	a = ap;
5783 	vp = a->a_vp;
5784 	ASSERT_VOP_IN_SEQC(vp);
5785 	if (!rc)
5786 		VFS_KNOTE_LOCKED(vp, NOTE_REVOKE);
5787 }
5788 
5789 void
5790 vop_remove_pre(void *ap)
5791 {
5792 	struct vop_remove_args *a;
5793 	struct vnode *dvp, *vp;
5794 
5795 	a = ap;
5796 	dvp = a->a_dvp;
5797 	vp = a->a_vp;
5798 	vn_seqc_write_begin(dvp);
5799 	vn_seqc_write_begin(vp);
5800 }
5801 
5802 void
5803 vop_remove_post(void *ap, int rc)
5804 {
5805 	struct vop_remove_args *a;
5806 	struct vnode *dvp, *vp;
5807 
5808 	a = ap;
5809 	dvp = a->a_dvp;
5810 	vp = a->a_vp;
5811 	vn_seqc_write_end(dvp);
5812 	vn_seqc_write_end(vp);
5813 	if (!rc) {
5814 		VFS_KNOTE_LOCKED(dvp, NOTE_WRITE);
5815 		VFS_KNOTE_LOCKED(vp, NOTE_DELETE);
5816 	}
5817 }
5818 
5819 void
5820 vop_rename_post(void *ap, int rc)
5821 {
5822 	struct vop_rename_args *a = ap;
5823 	long hint;
5824 
5825 	if (!rc) {
5826 		hint = NOTE_WRITE;
5827 		if (a->a_fdvp == a->a_tdvp) {
5828 			if (a->a_tvp != NULL && a->a_tvp->v_type == VDIR)
5829 				hint |= NOTE_LINK;
5830 			VFS_KNOTE_UNLOCKED(a->a_fdvp, hint);
5831 			VFS_KNOTE_UNLOCKED(a->a_tdvp, hint);
5832 		} else {
5833 			hint |= NOTE_EXTEND;
5834 			if (a->a_fvp->v_type == VDIR)
5835 				hint |= NOTE_LINK;
5836 			VFS_KNOTE_UNLOCKED(a->a_fdvp, hint);
5837 
5838 			if (a->a_fvp->v_type == VDIR && a->a_tvp != NULL &&
5839 			    a->a_tvp->v_type == VDIR)
5840 				hint &= ~NOTE_LINK;
5841 			VFS_KNOTE_UNLOCKED(a->a_tdvp, hint);
5842 		}
5843 
5844 		VFS_KNOTE_UNLOCKED(a->a_fvp, NOTE_RENAME);
5845 		if (a->a_tvp)
5846 			VFS_KNOTE_UNLOCKED(a->a_tvp, NOTE_DELETE);
5847 	}
5848 	if (a->a_tdvp != a->a_fdvp)
5849 		vdrop(a->a_fdvp);
5850 	if (a->a_tvp != a->a_fvp)
5851 		vdrop(a->a_fvp);
5852 	vdrop(a->a_tdvp);
5853 	if (a->a_tvp)
5854 		vdrop(a->a_tvp);
5855 }
5856 
5857 void
5858 vop_rmdir_pre(void *ap)
5859 {
5860 	struct vop_rmdir_args *a;
5861 	struct vnode *dvp, *vp;
5862 
5863 	a = ap;
5864 	dvp = a->a_dvp;
5865 	vp = a->a_vp;
5866 	vn_seqc_write_begin(dvp);
5867 	vn_seqc_write_begin(vp);
5868 }
5869 
5870 void
5871 vop_rmdir_post(void *ap, int rc)
5872 {
5873 	struct vop_rmdir_args *a;
5874 	struct vnode *dvp, *vp;
5875 
5876 	a = ap;
5877 	dvp = a->a_dvp;
5878 	vp = a->a_vp;
5879 	vn_seqc_write_end(dvp);
5880 	vn_seqc_write_end(vp);
5881 	if (!rc) {
5882 		VFS_KNOTE_LOCKED(dvp, NOTE_WRITE | NOTE_LINK);
5883 		VFS_KNOTE_LOCKED(vp, NOTE_DELETE);
5884 	}
5885 }
5886 
5887 void
5888 vop_setattr_pre(void *ap)
5889 {
5890 	struct vop_setattr_args *a;
5891 	struct vnode *vp;
5892 
5893 	a = ap;
5894 	vp = a->a_vp;
5895 	vn_seqc_write_begin(vp);
5896 }
5897 
5898 void
5899 vop_setattr_post(void *ap, int rc)
5900 {
5901 	struct vop_setattr_args *a;
5902 	struct vnode *vp;
5903 
5904 	a = ap;
5905 	vp = a->a_vp;
5906 	vn_seqc_write_end(vp);
5907 	if (!rc)
5908 		VFS_KNOTE_LOCKED(vp, NOTE_ATTRIB);
5909 }
5910 
5911 void
5912 vop_setacl_pre(void *ap)
5913 {
5914 	struct vop_setacl_args *a;
5915 	struct vnode *vp;
5916 
5917 	a = ap;
5918 	vp = a->a_vp;
5919 	vn_seqc_write_begin(vp);
5920 }
5921 
5922 void
5923 vop_setacl_post(void *ap, int rc __unused)
5924 {
5925 	struct vop_setacl_args *a;
5926 	struct vnode *vp;
5927 
5928 	a = ap;
5929 	vp = a->a_vp;
5930 	vn_seqc_write_end(vp);
5931 }
5932 
5933 void
5934 vop_setextattr_pre(void *ap)
5935 {
5936 	struct vop_setextattr_args *a;
5937 	struct vnode *vp;
5938 
5939 	a = ap;
5940 	vp = a->a_vp;
5941 	vn_seqc_write_begin(vp);
5942 }
5943 
5944 void
5945 vop_setextattr_post(void *ap, int rc)
5946 {
5947 	struct vop_setextattr_args *a;
5948 	struct vnode *vp;
5949 
5950 	a = ap;
5951 	vp = a->a_vp;
5952 	vn_seqc_write_end(vp);
5953 	if (!rc)
5954 		VFS_KNOTE_LOCKED(vp, NOTE_ATTRIB);
5955 }
5956 
5957 void
5958 vop_symlink_pre(void *ap)
5959 {
5960 	struct vop_symlink_args *a;
5961 	struct vnode *dvp;
5962 
5963 	a = ap;
5964 	dvp = a->a_dvp;
5965 	vn_seqc_write_begin(dvp);
5966 }
5967 
5968 void
5969 vop_symlink_post(void *ap, int rc)
5970 {
5971 	struct vop_symlink_args *a;
5972 	struct vnode *dvp;
5973 
5974 	a = ap;
5975 	dvp = a->a_dvp;
5976 	vn_seqc_write_end(dvp);
5977 	if (!rc)
5978 		VFS_KNOTE_LOCKED(dvp, NOTE_WRITE);
5979 }
5980 
5981 void
5982 vop_open_post(void *ap, int rc)
5983 {
5984 	struct vop_open_args *a = ap;
5985 
5986 	if (!rc)
5987 		VFS_KNOTE_LOCKED(a->a_vp, NOTE_OPEN);
5988 }
5989 
5990 void
5991 vop_close_post(void *ap, int rc)
5992 {
5993 	struct vop_close_args *a = ap;
5994 
5995 	if (!rc && (a->a_cred != NOCRED || /* filter out revokes */
5996 	    !VN_IS_DOOMED(a->a_vp))) {
5997 		VFS_KNOTE_LOCKED(a->a_vp, (a->a_fflag & FWRITE) != 0 ?
5998 		    NOTE_CLOSE_WRITE : NOTE_CLOSE);
5999 	}
6000 }
6001 
6002 void
6003 vop_read_post(void *ap, int rc)
6004 {
6005 	struct vop_read_args *a = ap;
6006 
6007 	if (!rc)
6008 		VFS_KNOTE_LOCKED(a->a_vp, NOTE_READ);
6009 }
6010 
6011 void
6012 vop_read_pgcache_post(void *ap, int rc)
6013 {
6014 	struct vop_read_pgcache_args *a = ap;
6015 
6016 	if (!rc)
6017 		VFS_KNOTE_UNLOCKED(a->a_vp, NOTE_READ);
6018 }
6019 
6020 void
6021 vop_readdir_post(void *ap, int rc)
6022 {
6023 	struct vop_readdir_args *a = ap;
6024 
6025 	if (!rc)
6026 		VFS_KNOTE_LOCKED(a->a_vp, NOTE_READ);
6027 }
6028 
6029 static struct knlist fs_knlist;
6030 
6031 static void
6032 vfs_event_init(void *arg)
6033 {
6034 	knlist_init_mtx(&fs_knlist, NULL);
6035 }
6036 /* XXX - correct order? */
6037 SYSINIT(vfs_knlist, SI_SUB_VFS, SI_ORDER_ANY, vfs_event_init, NULL);
6038 
6039 void
6040 vfs_event_signal(fsid_t *fsid, uint32_t event, intptr_t data __unused)
6041 {
6042 
6043 	KNOTE_UNLOCKED(&fs_knlist, event);
6044 }
6045 
6046 static int	filt_fsattach(struct knote *kn);
6047 static void	filt_fsdetach(struct knote *kn);
6048 static int	filt_fsevent(struct knote *kn, long hint);
6049 
6050 struct filterops fs_filtops = {
6051 	.f_isfd = 0,
6052 	.f_attach = filt_fsattach,
6053 	.f_detach = filt_fsdetach,
6054 	.f_event = filt_fsevent
6055 };
6056 
6057 static int
6058 filt_fsattach(struct knote *kn)
6059 {
6060 
6061 	kn->kn_flags |= EV_CLEAR;
6062 	knlist_add(&fs_knlist, kn, 0);
6063 	return (0);
6064 }
6065 
6066 static void
6067 filt_fsdetach(struct knote *kn)
6068 {
6069 
6070 	knlist_remove(&fs_knlist, kn, 0);
6071 }
6072 
6073 static int
6074 filt_fsevent(struct knote *kn, long hint)
6075 {
6076 
6077 	kn->kn_fflags |= kn->kn_sfflags & hint;
6078 
6079 	return (kn->kn_fflags != 0);
6080 }
6081 
6082 static int
6083 sysctl_vfs_ctl(SYSCTL_HANDLER_ARGS)
6084 {
6085 	struct vfsidctl vc;
6086 	int error;
6087 	struct mount *mp;
6088 
6089 	error = SYSCTL_IN(req, &vc, sizeof(vc));
6090 	if (error)
6091 		return (error);
6092 	if (vc.vc_vers != VFS_CTL_VERS1)
6093 		return (EINVAL);
6094 	mp = vfs_getvfs(&vc.vc_fsid);
6095 	if (mp == NULL)
6096 		return (ENOENT);
6097 	/* ensure that a specific sysctl goes to the right filesystem. */
6098 	if (strcmp(vc.vc_fstypename, "*") != 0 &&
6099 	    strcmp(vc.vc_fstypename, mp->mnt_vfc->vfc_name) != 0) {
6100 		vfs_rel(mp);
6101 		return (EINVAL);
6102 	}
6103 	VCTLTOREQ(&vc, req);
6104 	error = VFS_SYSCTL(mp, vc.vc_op, req);
6105 	vfs_rel(mp);
6106 	return (error);
6107 }
6108 
6109 SYSCTL_PROC(_vfs, OID_AUTO, ctl, CTLTYPE_OPAQUE | CTLFLAG_MPSAFE | CTLFLAG_WR,
6110     NULL, 0, sysctl_vfs_ctl, "",
6111     "Sysctl by fsid");
6112 
6113 /*
6114  * Function to initialize a va_filerev field sensibly.
6115  * XXX: Wouldn't a random number make a lot more sense ??
6116  */
6117 u_quad_t
6118 init_va_filerev(void)
6119 {
6120 	struct bintime bt;
6121 
6122 	getbinuptime(&bt);
6123 	return (((u_quad_t)bt.sec << 32LL) | (bt.frac >> 32LL));
6124 }
6125 
6126 static int	filt_vfsread(struct knote *kn, long hint);
6127 static int	filt_vfswrite(struct knote *kn, long hint);
6128 static int	filt_vfsvnode(struct knote *kn, long hint);
6129 static void	filt_vfsdetach(struct knote *kn);
6130 static struct filterops vfsread_filtops = {
6131 	.f_isfd = 1,
6132 	.f_detach = filt_vfsdetach,
6133 	.f_event = filt_vfsread
6134 };
6135 static struct filterops vfswrite_filtops = {
6136 	.f_isfd = 1,
6137 	.f_detach = filt_vfsdetach,
6138 	.f_event = filt_vfswrite
6139 };
6140 static struct filterops vfsvnode_filtops = {
6141 	.f_isfd = 1,
6142 	.f_detach = filt_vfsdetach,
6143 	.f_event = filt_vfsvnode
6144 };
6145 
6146 static void
6147 vfs_knllock(void *arg)
6148 {
6149 	struct vnode *vp = arg;
6150 
6151 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
6152 }
6153 
6154 static void
6155 vfs_knlunlock(void *arg)
6156 {
6157 	struct vnode *vp = arg;
6158 
6159 	VOP_UNLOCK(vp);
6160 }
6161 
6162 static void
6163 vfs_knl_assert_lock(void *arg, int what)
6164 {
6165 #ifdef DEBUG_VFS_LOCKS
6166 	struct vnode *vp = arg;
6167 
6168 	if (what == LA_LOCKED)
6169 		ASSERT_VOP_LOCKED(vp, "vfs_knl_assert_locked");
6170 	else
6171 		ASSERT_VOP_UNLOCKED(vp, "vfs_knl_assert_unlocked");
6172 #endif
6173 }
6174 
6175 int
6176 vfs_kqfilter(struct vop_kqfilter_args *ap)
6177 {
6178 	struct vnode *vp = ap->a_vp;
6179 	struct knote *kn = ap->a_kn;
6180 	struct knlist *knl;
6181 
6182 	switch (kn->kn_filter) {
6183 	case EVFILT_READ:
6184 		kn->kn_fop = &vfsread_filtops;
6185 		break;
6186 	case EVFILT_WRITE:
6187 		kn->kn_fop = &vfswrite_filtops;
6188 		break;
6189 	case EVFILT_VNODE:
6190 		kn->kn_fop = &vfsvnode_filtops;
6191 		break;
6192 	default:
6193 		return (EINVAL);
6194 	}
6195 
6196 	kn->kn_hook = (caddr_t)vp;
6197 
6198 	v_addpollinfo(vp);
6199 	if (vp->v_pollinfo == NULL)
6200 		return (ENOMEM);
6201 	knl = &vp->v_pollinfo->vpi_selinfo.si_note;
6202 	vhold(vp);
6203 	knlist_add(knl, kn, 0);
6204 
6205 	return (0);
6206 }
6207 
6208 /*
6209  * Detach knote from vnode
6210  */
6211 static void
6212 filt_vfsdetach(struct knote *kn)
6213 {
6214 	struct vnode *vp = (struct vnode *)kn->kn_hook;
6215 
6216 	KASSERT(vp->v_pollinfo != NULL, ("Missing v_pollinfo"));
6217 	knlist_remove(&vp->v_pollinfo->vpi_selinfo.si_note, kn, 0);
6218 	vdrop(vp);
6219 }
6220 
6221 /*ARGSUSED*/
6222 static int
6223 filt_vfsread(struct knote *kn, long hint)
6224 {
6225 	struct vnode *vp = (struct vnode *)kn->kn_hook;
6226 	struct vattr va;
6227 	int res;
6228 
6229 	/*
6230 	 * filesystem is gone, so set the EOF flag and schedule
6231 	 * the knote for deletion.
6232 	 */
6233 	if (hint == NOTE_REVOKE || (hint == 0 && vp->v_type == VBAD)) {
6234 		VI_LOCK(vp);
6235 		kn->kn_flags |= (EV_EOF | EV_ONESHOT);
6236 		VI_UNLOCK(vp);
6237 		return (1);
6238 	}
6239 
6240 	if (VOP_GETATTR(vp, &va, curthread->td_ucred))
6241 		return (0);
6242 
6243 	VI_LOCK(vp);
6244 	kn->kn_data = va.va_size - kn->kn_fp->f_offset;
6245 	res = (kn->kn_sfflags & NOTE_FILE_POLL) != 0 || kn->kn_data != 0;
6246 	VI_UNLOCK(vp);
6247 	return (res);
6248 }
6249 
6250 /*ARGSUSED*/
6251 static int
6252 filt_vfswrite(struct knote *kn, long hint)
6253 {
6254 	struct vnode *vp = (struct vnode *)kn->kn_hook;
6255 
6256 	VI_LOCK(vp);
6257 
6258 	/*
6259 	 * filesystem is gone, so set the EOF flag and schedule
6260 	 * the knote for deletion.
6261 	 */
6262 	if (hint == NOTE_REVOKE || (hint == 0 && vp->v_type == VBAD))
6263 		kn->kn_flags |= (EV_EOF | EV_ONESHOT);
6264 
6265 	kn->kn_data = 0;
6266 	VI_UNLOCK(vp);
6267 	return (1);
6268 }
6269 
6270 static int
6271 filt_vfsvnode(struct knote *kn, long hint)
6272 {
6273 	struct vnode *vp = (struct vnode *)kn->kn_hook;
6274 	int res;
6275 
6276 	VI_LOCK(vp);
6277 	if (kn->kn_sfflags & hint)
6278 		kn->kn_fflags |= hint;
6279 	if (hint == NOTE_REVOKE || (hint == 0 && vp->v_type == VBAD)) {
6280 		kn->kn_flags |= EV_EOF;
6281 		VI_UNLOCK(vp);
6282 		return (1);
6283 	}
6284 	res = (kn->kn_fflags != 0);
6285 	VI_UNLOCK(vp);
6286 	return (res);
6287 }
6288 
6289 /*
6290  * Returns whether the directory is empty or not.
6291  * If it is empty, the return value is 0; otherwise
6292  * the return value is an error value (which may
6293  * be ENOTEMPTY).
6294  */
6295 int
6296 vfs_emptydir(struct vnode *vp)
6297 {
6298 	struct uio uio;
6299 	struct iovec iov;
6300 	struct dirent *dirent, *dp, *endp;
6301 	int error, eof;
6302 
6303 	error = 0;
6304 	eof = 0;
6305 
6306 	ASSERT_VOP_LOCKED(vp, "vfs_emptydir");
6307 
6308 	dirent = malloc(sizeof(struct dirent), M_TEMP, M_WAITOK);
6309 	iov.iov_base = dirent;
6310 	iov.iov_len = sizeof(struct dirent);
6311 
6312 	uio.uio_iov = &iov;
6313 	uio.uio_iovcnt = 1;
6314 	uio.uio_offset = 0;
6315 	uio.uio_resid = sizeof(struct dirent);
6316 	uio.uio_segflg = UIO_SYSSPACE;
6317 	uio.uio_rw = UIO_READ;
6318 	uio.uio_td = curthread;
6319 
6320 	while (eof == 0 && error == 0) {
6321 		error = VOP_READDIR(vp, &uio, curthread->td_ucred, &eof,
6322 		    NULL, NULL);
6323 		if (error != 0)
6324 			break;
6325 		endp = (void *)((uint8_t *)dirent +
6326 		    sizeof(struct dirent) - uio.uio_resid);
6327 		for (dp = dirent; dp < endp;
6328 		     dp = (void *)((uint8_t *)dp + GENERIC_DIRSIZ(dp))) {
6329 			if (dp->d_type == DT_WHT)
6330 				continue;
6331 			if (dp->d_namlen == 0)
6332 				continue;
6333 			if (dp->d_type != DT_DIR &&
6334 			    dp->d_type != DT_UNKNOWN) {
6335 				error = ENOTEMPTY;
6336 				break;
6337 			}
6338 			if (dp->d_namlen > 2) {
6339 				error = ENOTEMPTY;
6340 				break;
6341 			}
6342 			if (dp->d_namlen == 1 &&
6343 			    dp->d_name[0] != '.') {
6344 				error = ENOTEMPTY;
6345 				break;
6346 			}
6347 			if (dp->d_namlen == 2 &&
6348 			    dp->d_name[1] != '.') {
6349 				error = ENOTEMPTY;
6350 				break;
6351 			}
6352 			uio.uio_resid = sizeof(struct dirent);
6353 		}
6354 	}
6355 	free(dirent, M_TEMP);
6356 	return (error);
6357 }
6358 
6359 int
6360 vfs_read_dirent(struct vop_readdir_args *ap, struct dirent *dp, off_t off)
6361 {
6362 	int error;
6363 
6364 	if (dp->d_reclen > ap->a_uio->uio_resid)
6365 		return (ENAMETOOLONG);
6366 	error = uiomove(dp, dp->d_reclen, ap->a_uio);
6367 	if (error) {
6368 		if (ap->a_ncookies != NULL) {
6369 			if (ap->a_cookies != NULL)
6370 				free(ap->a_cookies, M_TEMP);
6371 			ap->a_cookies = NULL;
6372 			*ap->a_ncookies = 0;
6373 		}
6374 		return (error);
6375 	}
6376 	if (ap->a_ncookies == NULL)
6377 		return (0);
6378 
6379 	KASSERT(ap->a_cookies,
6380 	    ("NULL ap->a_cookies value with non-NULL ap->a_ncookies!"));
6381 
6382 	*ap->a_cookies = realloc(*ap->a_cookies,
6383 	    (*ap->a_ncookies + 1) * sizeof(u_long), M_TEMP, M_WAITOK | M_ZERO);
6384 	(*ap->a_cookies)[*ap->a_ncookies] = off;
6385 	*ap->a_ncookies += 1;
6386 	return (0);
6387 }
6388 
6389 /*
6390  * The purpose of this routine is to remove granularity from accmode_t,
6391  * reducing it into standard unix access bits - VEXEC, VREAD, VWRITE,
6392  * VADMIN and VAPPEND.
6393  *
6394  * If it returns 0, the caller is supposed to continue with the usual
6395  * access checks using 'accmode' as modified by this routine.  If it
6396  * returns nonzero value, the caller is supposed to return that value
6397  * as errno.
6398  *
6399  * Note that after this routine runs, accmode may be zero.
6400  */
6401 int
6402 vfs_unixify_accmode(accmode_t *accmode)
6403 {
6404 	/*
6405 	 * There is no way to specify explicit "deny" rule using
6406 	 * file mode or POSIX.1e ACLs.
6407 	 */
6408 	if (*accmode & VEXPLICIT_DENY) {
6409 		*accmode = 0;
6410 		return (0);
6411 	}
6412 
6413 	/*
6414 	 * None of these can be translated into usual access bits.
6415 	 * Also, the common case for NFSv4 ACLs is to not contain
6416 	 * either of these bits. Caller should check for VWRITE
6417 	 * on the containing directory instead.
6418 	 */
6419 	if (*accmode & (VDELETE_CHILD | VDELETE))
6420 		return (EPERM);
6421 
6422 	if (*accmode & VADMIN_PERMS) {
6423 		*accmode &= ~VADMIN_PERMS;
6424 		*accmode |= VADMIN;
6425 	}
6426 
6427 	/*
6428 	 * There is no way to deny VREAD_ATTRIBUTES, VREAD_ACL
6429 	 * or VSYNCHRONIZE using file mode or POSIX.1e ACL.
6430 	 */
6431 	*accmode &= ~(VSTAT_PERMS | VSYNCHRONIZE);
6432 
6433 	return (0);
6434 }
6435 
6436 /*
6437  * Clear out a doomed vnode (if any) and replace it with a new one as long
6438  * as the fs is not being unmounted. Return the root vnode to the caller.
6439  */
6440 static int __noinline
6441 vfs_cache_root_fallback(struct mount *mp, int flags, struct vnode **vpp)
6442 {
6443 	struct vnode *vp;
6444 	int error;
6445 
6446 restart:
6447 	if (mp->mnt_rootvnode != NULL) {
6448 		MNT_ILOCK(mp);
6449 		vp = mp->mnt_rootvnode;
6450 		if (vp != NULL) {
6451 			if (!VN_IS_DOOMED(vp)) {
6452 				vrefact(vp);
6453 				MNT_IUNLOCK(mp);
6454 				error = vn_lock(vp, flags);
6455 				if (error == 0) {
6456 					*vpp = vp;
6457 					return (0);
6458 				}
6459 				vrele(vp);
6460 				goto restart;
6461 			}
6462 			/*
6463 			 * Clear the old one.
6464 			 */
6465 			mp->mnt_rootvnode = NULL;
6466 		}
6467 		MNT_IUNLOCK(mp);
6468 		if (vp != NULL) {
6469 			vfs_op_barrier_wait(mp);
6470 			vrele(vp);
6471 		}
6472 	}
6473 	error = VFS_CACHEDROOT(mp, flags, vpp);
6474 	if (error != 0)
6475 		return (error);
6476 	if (mp->mnt_vfs_ops == 0) {
6477 		MNT_ILOCK(mp);
6478 		if (mp->mnt_vfs_ops != 0) {
6479 			MNT_IUNLOCK(mp);
6480 			return (0);
6481 		}
6482 		if (mp->mnt_rootvnode == NULL) {
6483 			vrefact(*vpp);
6484 			mp->mnt_rootvnode = *vpp;
6485 		} else {
6486 			if (mp->mnt_rootvnode != *vpp) {
6487 				if (!VN_IS_DOOMED(mp->mnt_rootvnode)) {
6488 					panic("%s: mismatch between vnode returned "
6489 					    " by VFS_CACHEDROOT and the one cached "
6490 					    " (%p != %p)",
6491 					    __func__, *vpp, mp->mnt_rootvnode);
6492 				}
6493 			}
6494 		}
6495 		MNT_IUNLOCK(mp);
6496 	}
6497 	return (0);
6498 }
6499 
6500 int
6501 vfs_cache_root(struct mount *mp, int flags, struct vnode **vpp)
6502 {
6503 	struct mount_pcpu *mpcpu;
6504 	struct vnode *vp;
6505 	int error;
6506 
6507 	if (!vfs_op_thread_enter(mp, mpcpu))
6508 		return (vfs_cache_root_fallback(mp, flags, vpp));
6509 	vp = atomic_load_ptr(&mp->mnt_rootvnode);
6510 	if (vp == NULL || VN_IS_DOOMED(vp)) {
6511 		vfs_op_thread_exit(mp, mpcpu);
6512 		return (vfs_cache_root_fallback(mp, flags, vpp));
6513 	}
6514 	vrefact(vp);
6515 	vfs_op_thread_exit(mp, mpcpu);
6516 	error = vn_lock(vp, flags);
6517 	if (error != 0) {
6518 		vrele(vp);
6519 		return (vfs_cache_root_fallback(mp, flags, vpp));
6520 	}
6521 	*vpp = vp;
6522 	return (0);
6523 }
6524 
6525 struct vnode *
6526 vfs_cache_root_clear(struct mount *mp)
6527 {
6528 	struct vnode *vp;
6529 
6530 	/*
6531 	 * ops > 0 guarantees there is nobody who can see this vnode
6532 	 */
6533 	MPASS(mp->mnt_vfs_ops > 0);
6534 	vp = mp->mnt_rootvnode;
6535 	if (vp != NULL)
6536 		vn_seqc_write_begin(vp);
6537 	mp->mnt_rootvnode = NULL;
6538 	return (vp);
6539 }
6540 
6541 void
6542 vfs_cache_root_set(struct mount *mp, struct vnode *vp)
6543 {
6544 
6545 	MPASS(mp->mnt_vfs_ops > 0);
6546 	vrefact(vp);
6547 	mp->mnt_rootvnode = vp;
6548 }
6549 
6550 /*
6551  * These are helper functions for filesystems to traverse all
6552  * their vnodes.  See MNT_VNODE_FOREACH_ALL() in sys/mount.h.
6553  *
6554  * This interface replaces MNT_VNODE_FOREACH.
6555  */
6556 
6557 struct vnode *
6558 __mnt_vnode_next_all(struct vnode **mvp, struct mount *mp)
6559 {
6560 	struct vnode *vp;
6561 
6562 	if (should_yield())
6563 		kern_yield(PRI_USER);
6564 	MNT_ILOCK(mp);
6565 	KASSERT((*mvp)->v_mount == mp, ("marker vnode mount list mismatch"));
6566 	for (vp = TAILQ_NEXT(*mvp, v_nmntvnodes); vp != NULL;
6567 	    vp = TAILQ_NEXT(vp, v_nmntvnodes)) {
6568 		/* Allow a racy peek at VIRF_DOOMED to save a lock acquisition. */
6569 		if (vp->v_type == VMARKER || VN_IS_DOOMED(vp))
6570 			continue;
6571 		VI_LOCK(vp);
6572 		if (VN_IS_DOOMED(vp)) {
6573 			VI_UNLOCK(vp);
6574 			continue;
6575 		}
6576 		break;
6577 	}
6578 	if (vp == NULL) {
6579 		__mnt_vnode_markerfree_all(mvp, mp);
6580 		/* MNT_IUNLOCK(mp); -- done in above function */
6581 		mtx_assert(MNT_MTX(mp), MA_NOTOWNED);
6582 		return (NULL);
6583 	}
6584 	TAILQ_REMOVE(&mp->mnt_nvnodelist, *mvp, v_nmntvnodes);
6585 	TAILQ_INSERT_AFTER(&mp->mnt_nvnodelist, vp, *mvp, v_nmntvnodes);
6586 	MNT_IUNLOCK(mp);
6587 	return (vp);
6588 }
6589 
6590 struct vnode *
6591 __mnt_vnode_first_all(struct vnode **mvp, struct mount *mp)
6592 {
6593 	struct vnode *vp;
6594 
6595 	*mvp = vn_alloc_marker(mp);
6596 	MNT_ILOCK(mp);
6597 	MNT_REF(mp);
6598 
6599 	TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes) {
6600 		/* Allow a racy peek at VIRF_DOOMED to save a lock acquisition. */
6601 		if (vp->v_type == VMARKER || VN_IS_DOOMED(vp))
6602 			continue;
6603 		VI_LOCK(vp);
6604 		if (VN_IS_DOOMED(vp)) {
6605 			VI_UNLOCK(vp);
6606 			continue;
6607 		}
6608 		break;
6609 	}
6610 	if (vp == NULL) {
6611 		MNT_REL(mp);
6612 		MNT_IUNLOCK(mp);
6613 		vn_free_marker(*mvp);
6614 		*mvp = NULL;
6615 		return (NULL);
6616 	}
6617 	TAILQ_INSERT_AFTER(&mp->mnt_nvnodelist, vp, *mvp, v_nmntvnodes);
6618 	MNT_IUNLOCK(mp);
6619 	return (vp);
6620 }
6621 
6622 void
6623 __mnt_vnode_markerfree_all(struct vnode **mvp, struct mount *mp)
6624 {
6625 
6626 	if (*mvp == NULL) {
6627 		MNT_IUNLOCK(mp);
6628 		return;
6629 	}
6630 
6631 	mtx_assert(MNT_MTX(mp), MA_OWNED);
6632 
6633 	KASSERT((*mvp)->v_mount == mp, ("marker vnode mount list mismatch"));
6634 	TAILQ_REMOVE(&mp->mnt_nvnodelist, *mvp, v_nmntvnodes);
6635 	MNT_REL(mp);
6636 	MNT_IUNLOCK(mp);
6637 	vn_free_marker(*mvp);
6638 	*mvp = NULL;
6639 }
6640 
6641 /*
6642  * These are helper functions for filesystems to traverse their
6643  * lazy vnodes.  See MNT_VNODE_FOREACH_LAZY() in sys/mount.h
6644  */
6645 static void
6646 mnt_vnode_markerfree_lazy(struct vnode **mvp, struct mount *mp)
6647 {
6648 
6649 	KASSERT((*mvp)->v_mount == mp, ("marker vnode mount list mismatch"));
6650 
6651 	MNT_ILOCK(mp);
6652 	MNT_REL(mp);
6653 	MNT_IUNLOCK(mp);
6654 	vn_free_marker(*mvp);
6655 	*mvp = NULL;
6656 }
6657 
6658 /*
6659  * Relock the mp mount vnode list lock with the vp vnode interlock in the
6660  * conventional lock order during mnt_vnode_next_lazy iteration.
6661  *
6662  * On entry, the mount vnode list lock is held and the vnode interlock is not.
6663  * The list lock is dropped and reacquired.  On success, both locks are held.
6664  * On failure, the mount vnode list lock is held but the vnode interlock is
6665  * not, and the procedure may have yielded.
6666  */
6667 static bool
6668 mnt_vnode_next_lazy_relock(struct vnode *mvp, struct mount *mp,
6669     struct vnode *vp)
6670 {
6671 
6672 	VNASSERT(mvp->v_mount == mp && mvp->v_type == VMARKER &&
6673 	    TAILQ_NEXT(mvp, v_lazylist) != NULL, mvp,
6674 	    ("%s: bad marker", __func__));
6675 	VNASSERT(vp->v_mount == mp && vp->v_type != VMARKER, vp,
6676 	    ("%s: inappropriate vnode", __func__));
6677 	ASSERT_VI_UNLOCKED(vp, __func__);
6678 	mtx_assert(&mp->mnt_listmtx, MA_OWNED);
6679 
6680 	TAILQ_REMOVE(&mp->mnt_lazyvnodelist, mvp, v_lazylist);
6681 	TAILQ_INSERT_BEFORE(vp, mvp, v_lazylist);
6682 
6683 	/*
6684 	 * Note we may be racing against vdrop which transitioned the hold
6685 	 * count to 0 and now waits for the ->mnt_listmtx lock. This is fine,
6686 	 * if we are the only user after we get the interlock we will just
6687 	 * vdrop.
6688 	 */
6689 	vhold(vp);
6690 	mtx_unlock(&mp->mnt_listmtx);
6691 	VI_LOCK(vp);
6692 	if (VN_IS_DOOMED(vp)) {
6693 		VNPASS((vp->v_mflag & VMP_LAZYLIST) == 0, vp);
6694 		goto out_lost;
6695 	}
6696 	VNPASS(vp->v_mflag & VMP_LAZYLIST, vp);
6697 	/*
6698 	 * There is nothing to do if we are the last user.
6699 	 */
6700 	if (!refcount_release_if_not_last(&vp->v_holdcnt))
6701 		goto out_lost;
6702 	mtx_lock(&mp->mnt_listmtx);
6703 	return (true);
6704 out_lost:
6705 	vdropl(vp);
6706 	maybe_yield();
6707 	mtx_lock(&mp->mnt_listmtx);
6708 	return (false);
6709 }
6710 
6711 static struct vnode *
6712 mnt_vnode_next_lazy(struct vnode **mvp, struct mount *mp, mnt_lazy_cb_t *cb,
6713     void *cbarg)
6714 {
6715 	struct vnode *vp;
6716 
6717 	mtx_assert(&mp->mnt_listmtx, MA_OWNED);
6718 	KASSERT((*mvp)->v_mount == mp, ("marker vnode mount list mismatch"));
6719 restart:
6720 	vp = TAILQ_NEXT(*mvp, v_lazylist);
6721 	while (vp != NULL) {
6722 		if (vp->v_type == VMARKER) {
6723 			vp = TAILQ_NEXT(vp, v_lazylist);
6724 			continue;
6725 		}
6726 		/*
6727 		 * See if we want to process the vnode. Note we may encounter a
6728 		 * long string of vnodes we don't care about and hog the list
6729 		 * as a result. Check for it and requeue the marker.
6730 		 */
6731 		VNPASS(!VN_IS_DOOMED(vp), vp);
6732 		if (!cb(vp, cbarg)) {
6733 			if (!should_yield()) {
6734 				vp = TAILQ_NEXT(vp, v_lazylist);
6735 				continue;
6736 			}
6737 			TAILQ_REMOVE(&mp->mnt_lazyvnodelist, *mvp,
6738 			    v_lazylist);
6739 			TAILQ_INSERT_AFTER(&mp->mnt_lazyvnodelist, vp, *mvp,
6740 			    v_lazylist);
6741 			mtx_unlock(&mp->mnt_listmtx);
6742 			kern_yield(PRI_USER);
6743 			mtx_lock(&mp->mnt_listmtx);
6744 			goto restart;
6745 		}
6746 		/*
6747 		 * Try-lock because this is the wrong lock order.
6748 		 */
6749 		if (!VI_TRYLOCK(vp) &&
6750 		    !mnt_vnode_next_lazy_relock(*mvp, mp, vp))
6751 			goto restart;
6752 		KASSERT(vp->v_type != VMARKER, ("locked marker %p", vp));
6753 		KASSERT(vp->v_mount == mp || vp->v_mount == NULL,
6754 		    ("alien vnode on the lazy list %p %p", vp, mp));
6755 		VNPASS(vp->v_mount == mp, vp);
6756 		VNPASS(!VN_IS_DOOMED(vp), vp);
6757 		break;
6758 	}
6759 	TAILQ_REMOVE(&mp->mnt_lazyvnodelist, *mvp, v_lazylist);
6760 
6761 	/* Check if we are done */
6762 	if (vp == NULL) {
6763 		mtx_unlock(&mp->mnt_listmtx);
6764 		mnt_vnode_markerfree_lazy(mvp, mp);
6765 		return (NULL);
6766 	}
6767 	TAILQ_INSERT_AFTER(&mp->mnt_lazyvnodelist, vp, *mvp, v_lazylist);
6768 	mtx_unlock(&mp->mnt_listmtx);
6769 	ASSERT_VI_LOCKED(vp, "lazy iter");
6770 	return (vp);
6771 }
6772 
6773 struct vnode *
6774 __mnt_vnode_next_lazy(struct vnode **mvp, struct mount *mp, mnt_lazy_cb_t *cb,
6775     void *cbarg)
6776 {
6777 
6778 	if (should_yield())
6779 		kern_yield(PRI_USER);
6780 	mtx_lock(&mp->mnt_listmtx);
6781 	return (mnt_vnode_next_lazy(mvp, mp, cb, cbarg));
6782 }
6783 
6784 struct vnode *
6785 __mnt_vnode_first_lazy(struct vnode **mvp, struct mount *mp, mnt_lazy_cb_t *cb,
6786     void *cbarg)
6787 {
6788 	struct vnode *vp;
6789 
6790 	if (TAILQ_EMPTY(&mp->mnt_lazyvnodelist))
6791 		return (NULL);
6792 
6793 	*mvp = vn_alloc_marker(mp);
6794 	MNT_ILOCK(mp);
6795 	MNT_REF(mp);
6796 	MNT_IUNLOCK(mp);
6797 
6798 	mtx_lock(&mp->mnt_listmtx);
6799 	vp = TAILQ_FIRST(&mp->mnt_lazyvnodelist);
6800 	if (vp == NULL) {
6801 		mtx_unlock(&mp->mnt_listmtx);
6802 		mnt_vnode_markerfree_lazy(mvp, mp);
6803 		return (NULL);
6804 	}
6805 	TAILQ_INSERT_BEFORE(vp, *mvp, v_lazylist);
6806 	return (mnt_vnode_next_lazy(mvp, mp, cb, cbarg));
6807 }
6808 
6809 void
6810 __mnt_vnode_markerfree_lazy(struct vnode **mvp, struct mount *mp)
6811 {
6812 
6813 	if (*mvp == NULL)
6814 		return;
6815 
6816 	mtx_lock(&mp->mnt_listmtx);
6817 	TAILQ_REMOVE(&mp->mnt_lazyvnodelist, *mvp, v_lazylist);
6818 	mtx_unlock(&mp->mnt_listmtx);
6819 	mnt_vnode_markerfree_lazy(mvp, mp);
6820 }
6821 
6822 int
6823 vn_dir_check_exec(struct vnode *vp, struct componentname *cnp)
6824 {
6825 
6826 	if ((cnp->cn_flags & NOEXECCHECK) != 0) {
6827 		cnp->cn_flags &= ~NOEXECCHECK;
6828 		return (0);
6829 	}
6830 
6831 	return (VOP_ACCESS(vp, VEXEC, cnp->cn_cred, cnp->cn_thread));
6832 }
6833 
6834 /*
6835  * Do not use this variant unless you have means other than the hold count
6836  * to prevent the vnode from getting freed.
6837  */
6838 void
6839 vn_seqc_write_begin_unheld_locked(struct vnode *vp)
6840 {
6841 
6842 	ASSERT_VI_LOCKED(vp, __func__);
6843 	VNPASS(vp->v_seqc_users >= 0, vp);
6844 	vp->v_seqc_users++;
6845 	if (vp->v_seqc_users == 1)
6846 		seqc_sleepable_write_begin(&vp->v_seqc);
6847 }
6848 
6849 void
6850 vn_seqc_write_begin_locked(struct vnode *vp)
6851 {
6852 
6853 	ASSERT_VI_LOCKED(vp, __func__);
6854 	VNPASS(vp->v_holdcnt > 0, vp);
6855 	vn_seqc_write_begin_unheld_locked(vp);
6856 }
6857 
6858 void
6859 vn_seqc_write_begin(struct vnode *vp)
6860 {
6861 
6862 	VI_LOCK(vp);
6863 	vn_seqc_write_begin_locked(vp);
6864 	VI_UNLOCK(vp);
6865 }
6866 
6867 void
6868 vn_seqc_write_begin_unheld(struct vnode *vp)
6869 {
6870 
6871 	VI_LOCK(vp);
6872 	vn_seqc_write_begin_unheld_locked(vp);
6873 	VI_UNLOCK(vp);
6874 }
6875 
6876 void
6877 vn_seqc_write_end_locked(struct vnode *vp)
6878 {
6879 
6880 	ASSERT_VI_LOCKED(vp, __func__);
6881 	VNPASS(vp->v_seqc_users > 0, vp);
6882 	vp->v_seqc_users--;
6883 	if (vp->v_seqc_users == 0)
6884 		seqc_sleepable_write_end(&vp->v_seqc);
6885 }
6886 
6887 void
6888 vn_seqc_write_end(struct vnode *vp)
6889 {
6890 
6891 	VI_LOCK(vp);
6892 	vn_seqc_write_end_locked(vp);
6893 	VI_UNLOCK(vp);
6894 }
6895 
6896 /*
6897  * Special case handling for allocating and freeing vnodes.
6898  *
6899  * The counter remains unchanged on free so that a doomed vnode will
6900  * keep testing as in modify as long as it is accessible with SMR.
6901  */
6902 static void
6903 vn_seqc_init(struct vnode *vp)
6904 {
6905 
6906 	vp->v_seqc = 0;
6907 	vp->v_seqc_users = 0;
6908 }
6909 
6910 static void
6911 vn_seqc_write_end_free(struct vnode *vp)
6912 {
6913 
6914 	VNPASS(seqc_in_modify(vp->v_seqc), vp);
6915 	VNPASS(vp->v_seqc_users == 1, vp);
6916 }
6917 
6918 void
6919 vn_irflag_set_locked(struct vnode *vp, short toset)
6920 {
6921 	short flags;
6922 
6923 	ASSERT_VI_LOCKED(vp, __func__);
6924 	flags = vn_irflag_read(vp);
6925 	VNASSERT((flags & toset) == 0, vp,
6926 	    ("%s: some of the passed flags already set (have %d, passed %d)\n",
6927 	    __func__, flags, toset));
6928 	atomic_store_short(&vp->v_irflag, flags | toset);
6929 }
6930 
6931 void
6932 vn_irflag_set(struct vnode *vp, short toset)
6933 {
6934 
6935 	VI_LOCK(vp);
6936 	vn_irflag_set_locked(vp, toset);
6937 	VI_UNLOCK(vp);
6938 }
6939 
6940 void
6941 vn_irflag_set_cond_locked(struct vnode *vp, short toset)
6942 {
6943 	short flags;
6944 
6945 	ASSERT_VI_LOCKED(vp, __func__);
6946 	flags = vn_irflag_read(vp);
6947 	atomic_store_short(&vp->v_irflag, flags | toset);
6948 }
6949 
6950 void
6951 vn_irflag_set_cond(struct vnode *vp, short toset)
6952 {
6953 
6954 	VI_LOCK(vp);
6955 	vn_irflag_set_cond_locked(vp, toset);
6956 	VI_UNLOCK(vp);
6957 }
6958 
6959 void
6960 vn_irflag_unset_locked(struct vnode *vp, short tounset)
6961 {
6962 	short flags;
6963 
6964 	ASSERT_VI_LOCKED(vp, __func__);
6965 	flags = vn_irflag_read(vp);
6966 	VNASSERT((flags & tounset) == tounset, vp,
6967 	    ("%s: some of the passed flags not set (have %d, passed %d)\n",
6968 	    __func__, flags, tounset));
6969 	atomic_store_short(&vp->v_irflag, flags & ~tounset);
6970 }
6971 
6972 void
6973 vn_irflag_unset(struct vnode *vp, short tounset)
6974 {
6975 
6976 	VI_LOCK(vp);
6977 	vn_irflag_unset_locked(vp, tounset);
6978 	VI_UNLOCK(vp);
6979 }
6980