xref: /freebsd/sys/kern/vfs_mount.c (revision 84ee9401a3fc8d3c22424266f421a928989cd692)
1 /*-
2  * Copyright (c) 1999-2004 Poul-Henning Kamp
3  * Copyright (c) 1999 Michael Smith
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  * 4. 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 AUTHOR 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 AUTHOR 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 
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
39 
40 #include <sys/param.h>
41 #include <sys/conf.h>
42 #include <sys/clock.h>
43 #include <sys/jail.h>
44 #include <sys/kernel.h>
45 #include <sys/libkern.h>
46 #include <sys/mac.h>
47 #include <sys/malloc.h>
48 #include <sys/mount.h>
49 #include <sys/mutex.h>
50 #include <sys/namei.h>
51 #include <sys/proc.h>
52 #include <sys/filedesc.h>
53 #include <sys/reboot.h>
54 #include <sys/syscallsubr.h>
55 #include <sys/sysproto.h>
56 #include <sys/sx.h>
57 #include <sys/sysctl.h>
58 #include <sys/sysent.h>
59 #include <sys/systm.h>
60 #include <sys/vnode.h>
61 #include <vm/uma.h>
62 
63 #include <geom/geom.h>
64 
65 #include <machine/stdarg.h>
66 
67 #include <security/audit/audit.h>
68 
69 #include "opt_rootdevname.h"
70 #include "opt_ddb.h"
71 #include "opt_mac.h"
72 
73 #ifdef DDB
74 #include <ddb/ddb.h>
75 #endif
76 
77 #define	ROOTNAME		"root_device"
78 #define	VFS_MOUNTARG_SIZE_MAX	(1024 * 64)
79 
80 static int	vfs_domount(struct thread *td, const char *fstype,
81 		    char *fspath, int fsflags, void *fsdata);
82 static struct mount *vfs_mount_alloc(struct vnode *dvp, struct vfsconf *vfsp,
83 		    const char *fspath, struct thread *td);
84 static int	vfs_mountroot_ask(void);
85 static int	vfs_mountroot_try(const char *mountfrom);
86 static int	vfs_donmount(struct thread *td, int fsflags,
87 		    struct uio *fsoptions);
88 static void	free_mntarg(struct mntarg *ma);
89 static void	vfs_mount_destroy(struct mount *);
90 static int	vfs_getopt_pos(struct vfsoptlist *opts, const char *name);
91 
92 static int	usermount = 0;
93 SYSCTL_INT(_vfs, OID_AUTO, usermount, CTLFLAG_RW, &usermount, 0,
94     "Unprivileged users may mount and unmount file systems");
95 
96 MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
97 MALLOC_DEFINE(M_VNODE_MARKER, "vnodemarker", "vnode marker");
98 static uma_zone_t mount_zone;
99 
100 /* List of mounted filesystems. */
101 struct mntlist mountlist = TAILQ_HEAD_INITIALIZER(mountlist);
102 
103 /* For any iteration/modification of mountlist */
104 struct mtx mountlist_mtx;
105 MTX_SYSINIT(mountlist, &mountlist_mtx, "mountlist", MTX_DEF);
106 
107 TAILQ_HEAD(vfsoptlist, vfsopt);
108 struct vfsopt {
109 	TAILQ_ENTRY(vfsopt) link;
110 	char	*name;
111 	void	*value;
112 	int	len;
113 };
114 
115 /*
116  * The vnode of the system's root (/ in the filesystem, without chroot
117  * active.)
118  */
119 struct vnode	*rootvnode;
120 
121 /*
122  * The root filesystem is detailed in the kernel environment variable
123  * vfs.root.mountfrom, which is expected to be in the general format
124  *
125  * <vfsname>:[<path>]
126  * vfsname   := the name of a VFS known to the kernel and capable
127  *              of being mounted as root
128  * path      := disk device name or other data used by the filesystem
129  *              to locate its physical store
130  */
131 
132 /*
133  * Global opts, taken by all filesystems
134  */
135 static const char *global_opts[] = {
136 	"errmsg",
137 	"fstype",
138 	"fspath",
139 	"rdonly",
140 	"ro",
141 	"rw",
142 	"suid",
143 	"exec",
144 	"update",
145 	NULL
146 };
147 
148 /*
149  * The root specifiers we will try if RB_CDROM is specified.
150  */
151 static char *cdrom_rootdevnames[] = {
152 	"cd9660:cd0",
153 	"cd9660:acd0",
154 	NULL
155 };
156 
157 /* legacy find-root code */
158 char		*rootdevnames[2] = {NULL, NULL};
159 #ifndef ROOTDEVNAME
160 #  define ROOTDEVNAME NULL
161 #endif
162 static const char	*ctrootdevname = ROOTDEVNAME;
163 
164 /*
165  * ---------------------------------------------------------------------
166  * Functions for building and sanitizing the mount options
167  */
168 
169 /* Remove one mount option. */
170 static void
171 vfs_freeopt(struct vfsoptlist *opts, struct vfsopt *opt)
172 {
173 
174 	TAILQ_REMOVE(opts, opt, link);
175 	free(opt->name, M_MOUNT);
176 	if (opt->value != NULL)
177 		free(opt->value, M_MOUNT);
178 #ifdef INVARIANTS
179 	else if (opt->len != 0)
180 		panic("%s: mount option with NULL value but length != 0",
181 		    __func__);
182 #endif
183 	free(opt, M_MOUNT);
184 }
185 
186 /* Release all resources related to the mount options. */
187 static void
188 vfs_freeopts(struct vfsoptlist *opts)
189 {
190 	struct vfsopt *opt;
191 
192 	while (!TAILQ_EMPTY(opts)) {
193 		opt = TAILQ_FIRST(opts);
194 		vfs_freeopt(opts, opt);
195 	}
196 	free(opts, M_MOUNT);
197 }
198 
199 /*
200  * Check if options are equal (with or without the "no" prefix).
201  */
202 static int
203 vfs_equalopts(const char *opt1, const char *opt2)
204 {
205 
206 	/* "opt" vs. "opt" or "noopt" vs. "noopt" */
207 	if (strcmp(opt1, opt2) == 0)
208 		return (1);
209 	/* "noopt" vs. "opt" */
210 	if (strncmp(opt1, "no", 2) == 0 && strcmp(opt1 + 2, opt2) == 0)
211 		return (1);
212 	/* "opt" vs. "noopt" */
213 	if (strncmp(opt2, "no", 2) == 0 && strcmp(opt1, opt2 + 2) == 0)
214 		return (1);
215 	return (0);
216 }
217 
218 /*
219  * If a mount option is specified several times,
220  * (with or without the "no" prefix) only keep
221  * the last occurence of it.
222  */
223 static void
224 vfs_sanitizeopts(struct vfsoptlist *opts)
225 {
226 	struct vfsopt *opt, *opt2, *tmp;
227 
228 	TAILQ_FOREACH_REVERSE(opt, opts, vfsoptlist, link) {
229 		opt2 = TAILQ_PREV(opt, vfsoptlist, link);
230 		while (opt2 != NULL) {
231 			if (vfs_equalopts(opt->name, opt2->name)) {
232 				tmp = TAILQ_PREV(opt2, vfsoptlist, link);
233 				vfs_freeopt(opts, opt2);
234 				opt2 = tmp;
235 			} else {
236 				opt2 = TAILQ_PREV(opt2, vfsoptlist, link);
237 			}
238 		}
239 	}
240 }
241 
242 /*
243  * Build a linked list of mount options from a struct uio.
244  */
245 static int
246 vfs_buildopts(struct uio *auio, struct vfsoptlist **options)
247 {
248 	struct vfsoptlist *opts;
249 	struct vfsopt *opt;
250 	size_t memused;
251 	unsigned int i, iovcnt;
252 	int error, namelen, optlen;
253 
254 	opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
255 	TAILQ_INIT(opts);
256 	memused = 0;
257 	iovcnt = auio->uio_iovcnt;
258 	for (i = 0; i < iovcnt; i += 2) {
259 		opt = malloc(sizeof(struct vfsopt), M_MOUNT, M_WAITOK);
260 		namelen = auio->uio_iov[i].iov_len;
261 		optlen = auio->uio_iov[i + 1].iov_len;
262 		opt->name = malloc(namelen, M_MOUNT, M_WAITOK);
263 		opt->value = NULL;
264 		opt->len = 0;
265 
266 		/*
267 		 * Do this early, so jumps to "bad" will free the current
268 		 * option.
269 		 */
270 		TAILQ_INSERT_TAIL(opts, opt, link);
271 		memused += sizeof(struct vfsopt) + optlen + namelen;
272 
273 		/*
274 		 * Avoid consuming too much memory, and attempts to overflow
275 		 * memused.
276 		 */
277 		if (memused > VFS_MOUNTARG_SIZE_MAX ||
278 		    optlen > VFS_MOUNTARG_SIZE_MAX ||
279 		    namelen > VFS_MOUNTARG_SIZE_MAX) {
280 			error = EINVAL;
281 			goto bad;
282 		}
283 
284 		if (auio->uio_segflg == UIO_SYSSPACE) {
285 			bcopy(auio->uio_iov[i].iov_base, opt->name, namelen);
286 		} else {
287 			error = copyin(auio->uio_iov[i].iov_base, opt->name,
288 			    namelen);
289 			if (error)
290 				goto bad;
291 		}
292 		/* Ensure names are null-terminated strings. */
293 		if (opt->name[namelen - 1] != '\0') {
294 			error = EINVAL;
295 			goto bad;
296 		}
297 		if (optlen != 0) {
298 			opt->len = optlen;
299 			opt->value = malloc(optlen, M_MOUNT, M_WAITOK);
300 			if (auio->uio_segflg == UIO_SYSSPACE) {
301 				bcopy(auio->uio_iov[i + 1].iov_base, opt->value,
302 				    optlen);
303 			} else {
304 				error = copyin(auio->uio_iov[i + 1].iov_base,
305 				    opt->value, optlen);
306 				if (error)
307 					goto bad;
308 			}
309 		}
310 	}
311 	vfs_sanitizeopts(opts);
312 	*options = opts;
313 	return (0);
314 bad:
315 	vfs_freeopts(opts);
316 	return (error);
317 }
318 
319 /*
320  * Merge the old mount options with the new ones passed
321  * in the MNT_UPDATE case.
322  */
323 static void
324 vfs_mergeopts(struct vfsoptlist *toopts, struct vfsoptlist *opts)
325 {
326 	struct vfsopt *opt, *opt2, *new;
327 
328 	TAILQ_FOREACH(opt, opts, link) {
329 		/*
330 		 * Check that this option hasn't been redefined
331 		 * nor cancelled with a "no" mount option.
332 		 */
333 		opt2 = TAILQ_FIRST(toopts);
334 		while (opt2 != NULL) {
335 			if (strcmp(opt2->name, opt->name) == 0)
336 				goto next;
337 			if (strncmp(opt2->name, "no", 2) == 0 &&
338 			    strcmp(opt2->name + 2, opt->name) == 0) {
339 				vfs_freeopt(toopts, opt2);
340 				goto next;
341 			}
342 			opt2 = TAILQ_NEXT(opt2, link);
343 		}
344 		/* We want this option, duplicate it. */
345 		new = malloc(sizeof(struct vfsopt), M_MOUNT, M_WAITOK);
346 		new->name = malloc(strlen(opt->name) + 1, M_MOUNT, M_WAITOK);
347 		strcpy(new->name, opt->name);
348 		if (opt->len != 0) {
349 			new->value = malloc(opt->len, M_MOUNT, M_WAITOK);
350 			bcopy(opt->value, new->value, opt->len);
351 		} else {
352 			new->value = NULL;
353 		}
354 		new->len = opt->len;
355 		TAILQ_INSERT_TAIL(toopts, new, link);
356 next:
357 		continue;
358 	}
359 }
360 
361 /*
362  * ---------------------------------------------------------------------
363  * Mount a filesystem
364  */
365 int
366 nmount(td, uap)
367 	struct thread *td;
368 	struct nmount_args /* {
369 		struct iovec *iovp;
370 		unsigned int iovcnt;
371 		int flags;
372 	} */ *uap;
373 {
374 	struct uio *auio;
375 	struct iovec *iov;
376 	unsigned int i;
377 	int error;
378 	u_int iovcnt;
379 
380 	AUDIT_ARG(fflags, uap->flags);
381 
382 	/* Kick out MNT_ROOTFS early as it is legal internally */
383 	if (uap->flags & MNT_ROOTFS)
384 		return (EINVAL);
385 
386 	iovcnt = uap->iovcnt;
387 	/*
388 	 * Check that we have an even number of iovec's
389 	 * and that we have at least two options.
390 	 */
391 	if ((iovcnt & 1) || (iovcnt < 4))
392 		return (EINVAL);
393 
394 	error = copyinuio(uap->iovp, iovcnt, &auio);
395 	if (error)
396 		return (error);
397 	iov = auio->uio_iov;
398 	for (i = 0; i < iovcnt; i++) {
399 		if (iov->iov_len > MMAXOPTIONLEN) {
400 			free(auio, M_IOV);
401 			return (EINVAL);
402 		}
403 		iov++;
404 	}
405 	error = vfs_donmount(td, uap->flags, auio);
406 
407 	free(auio, M_IOV);
408 	return (error);
409 }
410 
411 /*
412  * ---------------------------------------------------------------------
413  * Various utility functions
414  */
415 
416 void
417 vfs_ref(struct mount *mp)
418 {
419 
420 	MNT_ILOCK(mp);
421 	MNT_REF(mp);
422 	MNT_IUNLOCK(mp);
423 }
424 
425 void
426 vfs_rel(struct mount *mp)
427 {
428 
429 	MNT_ILOCK(mp);
430 	MNT_REL(mp);
431 	MNT_IUNLOCK(mp);
432 }
433 
434 static int
435 mount_init(void *mem, int size, int flags)
436 {
437 	struct mount *mp;
438 
439 	mp = (struct mount *)mem;
440 	mtx_init(&mp->mnt_mtx, "struct mount mtx", NULL, MTX_DEF);
441 	lockinit(&mp->mnt_lock, PVFS, "vfslock", 0, 0);
442 	return (0);
443 }
444 
445 static void
446 mount_fini(void *mem, int size)
447 {
448 	struct mount *mp;
449 
450 	mp = (struct mount *)mem;
451 	lockdestroy(&mp->mnt_lock);
452 	mtx_destroy(&mp->mnt_mtx);
453 }
454 
455 /*
456  * Allocate and initialize the mount point struct.
457  */
458 static struct mount *
459 vfs_mount_alloc(struct vnode *vp, struct vfsconf *vfsp,
460     const char *fspath, struct thread *td)
461 {
462 	struct mount *mp;
463 
464 	mp = uma_zalloc(mount_zone, M_WAITOK);
465 	bzero(&mp->mnt_startzero,
466 	    __rangeof(struct mount, mnt_startzero, mnt_endzero));
467 	TAILQ_INIT(&mp->mnt_nvnodelist);
468 	mp->mnt_nvnodelistsize = 0;
469 	mp->mnt_ref = 0;
470 	(void) vfs_busy(mp, LK_NOWAIT, 0, td);
471 	mp->mnt_op = vfsp->vfc_vfsops;
472 	mp->mnt_vfc = vfsp;
473 	vfsp->vfc_refcount++;	/* XXX Unlocked */
474 	mp->mnt_stat.f_type = vfsp->vfc_typenum;
475 	MNT_ILOCK(mp);
476 	mp->mnt_flag |= vfsp->vfc_flags & MNT_VISFLAGMASK;
477 	MNT_IUNLOCK(mp);
478 	mp->mnt_gen++;
479 	strlcpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
480 	mp->mnt_vnodecovered = vp;
481 	mp->mnt_cred = crdup(td->td_ucred);
482 	mp->mnt_stat.f_owner = td->td_ucred->cr_uid;
483 	strlcpy(mp->mnt_stat.f_mntonname, fspath, MNAMELEN);
484 	mp->mnt_iosize_max = DFLTPHYS;
485 #ifdef MAC
486 	mac_init_mount(mp);
487 	mac_create_mount(td->td_ucred, mp);
488 #endif
489 	arc4rand(&mp->mnt_hashseed, sizeof mp->mnt_hashseed, 0);
490 	return (mp);
491 }
492 
493 /*
494  * Destroy the mount struct previously allocated by vfs_mount_alloc().
495  */
496 static void
497 vfs_mount_destroy(struct mount *mp)
498 {
499 	int i;
500 
501 	MNT_ILOCK(mp);
502 	for (i = 0; mp->mnt_ref && i < 3; i++)
503 		msleep(mp, MNT_MTX(mp), PVFS, "mntref", hz);
504 	/*
505 	 * This will always cause a 3 second delay in rebooting due to
506 	 * refs on the root mountpoint that never go away.  Most of these
507 	 * are held by init which never exits.
508 	 */
509 	if (i == 3 && (!rebooting || bootverbose))
510 		printf("Mount point %s had %d dangling refs\n",
511 		    mp->mnt_stat.f_mntonname, mp->mnt_ref);
512 	if (mp->mnt_holdcnt != 0) {
513 		printf("Waiting for mount point to be unheld\n");
514 		while (mp->mnt_holdcnt != 0) {
515 			mp->mnt_holdcntwaiters++;
516 			msleep(&mp->mnt_holdcnt, MNT_MTX(mp),
517 			       PZERO, "mntdestroy", 0);
518 			mp->mnt_holdcntwaiters--;
519 		}
520 		printf("mount point unheld\n");
521 	}
522 	if (mp->mnt_writeopcount > 0) {
523 		printf("Waiting for mount point write ops\n");
524 		while (mp->mnt_writeopcount > 0) {
525 			mp->mnt_kern_flag |= MNTK_SUSPEND;
526 			msleep(&mp->mnt_writeopcount,
527 			       MNT_MTX(mp),
528 			       PZERO, "mntdestroy2", 0);
529 		}
530 		printf("mount point write ops completed\n");
531 	}
532 	if (mp->mnt_secondary_writes > 0) {
533 		printf("Waiting for mount point secondary write ops\n");
534 		while (mp->mnt_secondary_writes > 0) {
535 			mp->mnt_kern_flag |= MNTK_SUSPEND;
536 			msleep(&mp->mnt_secondary_writes,
537 			       MNT_MTX(mp),
538 			       PZERO, "mntdestroy3", 0);
539 		}
540 		printf("mount point secondary write ops completed\n");
541 	}
542 	MNT_IUNLOCK(mp);
543 	mp->mnt_vfc->vfc_refcount--;
544 	if (!TAILQ_EMPTY(&mp->mnt_nvnodelist)) {
545 		struct vnode *vp;
546 
547 		TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes)
548 			vprint("", vp);
549 		panic("unmount: dangling vnode");
550 	}
551 	MNT_ILOCK(mp);
552 	if (mp->mnt_kern_flag & MNTK_MWAIT)
553 		wakeup(mp);
554 	if (mp->mnt_writeopcount != 0)
555 		panic("vfs_mount_destroy: nonzero writeopcount");
556 	if (mp->mnt_secondary_writes != 0)
557 		panic("vfs_mount_destroy: nonzero secondary_writes");
558 	if (mp->mnt_nvnodelistsize != 0)
559 		panic("vfs_mount_destroy: nonzero nvnodelistsize");
560 	mp->mnt_writeopcount = -1000;
561 	mp->mnt_nvnodelistsize = -1000;
562 	mp->mnt_secondary_writes = -1000;
563 	MNT_IUNLOCK(mp);
564 #ifdef MAC
565 	mac_destroy_mount(mp);
566 #endif
567 	if (mp->mnt_opt != NULL)
568 		vfs_freeopts(mp->mnt_opt);
569 	crfree(mp->mnt_cred);
570 	uma_zfree(mount_zone, mp);
571 }
572 
573 static int
574 vfs_donmount(struct thread *td, int fsflags, struct uio *fsoptions)
575 {
576 	struct vfsoptlist *optlist;
577 	struct vfsopt *opt, *noro_opt;
578 	char *fstype, *fspath, *errmsg;
579 	int error, fstypelen, fspathlen, errmsg_len, errmsg_pos;
580 	int has_rw, has_noro;
581 
582 	errmsg = NULL;
583 	errmsg_len = 0;
584 	errmsg_pos = -1;
585 	has_rw = 0;
586 	has_noro = 0;
587 
588 	error = vfs_buildopts(fsoptions, &optlist);
589 	if (error)
590 		return (error);
591 
592 	if (vfs_getopt(optlist, "errmsg", (void **)&errmsg, &errmsg_len) == 0)
593 		errmsg_pos = vfs_getopt_pos(optlist, "errmsg");
594 
595 	/*
596 	 * We need these two options before the others,
597 	 * and they are mandatory for any filesystem.
598 	 * Ensure they are NUL terminated as well.
599 	 */
600 	fstypelen = 0;
601 	error = vfs_getopt(optlist, "fstype", (void **)&fstype, &fstypelen);
602 	if (error || fstype[fstypelen - 1] != '\0') {
603 		error = EINVAL;
604 		if (errmsg != NULL)
605 			strncpy(errmsg, "Invalid fstype", errmsg_len);
606 		goto bail;
607 	}
608 	fspathlen = 0;
609 	error = vfs_getopt(optlist, "fspath", (void **)&fspath, &fspathlen);
610 	if (error || fspath[fspathlen - 1] != '\0') {
611 		error = EINVAL;
612 		if (errmsg != NULL)
613 			strncpy(errmsg, "Invalid fspath", errmsg_len);
614 		goto bail;
615 	}
616 
617 	/*
618 	 * We need to see if we have the "update" option
619 	 * before we call vfs_domount(), since vfs_domount() has special
620 	 * logic based on MNT_UPDATE.  This is very important
621 	 * when we want to update the root filesystem.
622 	 */
623 	TAILQ_FOREACH(opt, optlist, link) {
624 		if (strcmp(opt->name, "update") == 0)
625 			fsflags |= MNT_UPDATE;
626 		else if (strcmp(opt->name, "async") == 0)
627 			fsflags |= MNT_ASYNC;
628 		else if (strcmp(opt->name, "force") == 0)
629 			fsflags |= MNT_FORCE;
630 		else if (strcmp(opt->name, "multilabel") == 0)
631 			fsflags |= MNT_MULTILABEL;
632 		else if (strcmp(opt->name, "noasync") == 0)
633 			fsflags &= ~MNT_ASYNC;
634 		else if (strcmp(opt->name, "noatime") == 0)
635 			fsflags |= MNT_NOATIME;
636 		else if (strcmp(opt->name, "noclusterr") == 0)
637 			fsflags |= MNT_NOCLUSTERR;
638 		else if (strcmp(opt->name, "noclusterw") == 0)
639 			fsflags |= MNT_NOCLUSTERW;
640 		else if (strcmp(opt->name, "noexec") == 0)
641 			fsflags |= MNT_NOEXEC;
642 		else if (strcmp(opt->name, "nosuid") == 0)
643 			fsflags |= MNT_NOSUID;
644 		else if (strcmp(opt->name, "nosymfollow") == 0)
645 			fsflags |= MNT_NOSYMFOLLOW;
646 		else if (strcmp(opt->name, "noro") == 0) {
647 			fsflags &= ~MNT_RDONLY;
648 			has_noro = 1;
649 		}
650 		else if (strcmp(opt->name, "rw") == 0) {
651 			fsflags &= ~MNT_RDONLY;
652 			has_rw = 1;
653 		}
654 		else if (strcmp(opt->name, "ro") == 0 ||
655 		    strcmp(opt->name, "rdonly") == 0)
656 			fsflags |= MNT_RDONLY;
657 		else if (strcmp(opt->name, "snapshot") == 0)
658 			fsflags |= MNT_SNAPSHOT;
659 		else if (strcmp(opt->name, "suiddir") == 0)
660 			fsflags |= MNT_SUIDDIR;
661 		else if (strcmp(opt->name, "sync") == 0)
662 			fsflags |= MNT_SYNCHRONOUS;
663 		else if (strcmp(opt->name, "union") == 0)
664 			fsflags |= MNT_UNION;
665 	}
666 
667 	/*
668 	 * If "rw" was specified as a mount option, and we
669 	 * are trying to update a mount-point from "ro" to "rw",
670 	 * we need a mount option "noro", since in vfs_mergeopts(),
671 	 * "noro" will cancel "ro", but "rw" will not do anything.
672 	 */
673 	if (has_rw && !has_noro) {
674 		noro_opt = malloc(sizeof(struct vfsopt), M_MOUNT, M_WAITOK);
675 		noro_opt->name = strdup("noro", M_MOUNT);
676 		noro_opt->value = NULL;
677 		noro_opt->len = 0;
678 		TAILQ_INSERT_TAIL(optlist, noro_opt, link);
679 	}
680 
681 	/*
682 	 * Be ultra-paranoid about making sure the type and fspath
683 	 * variables will fit in our mp buffers, including the
684 	 * terminating NUL.
685 	 */
686 	if (fstypelen >= MFSNAMELEN - 1 || fspathlen >= MNAMELEN - 1) {
687 		error = ENAMETOOLONG;
688 		goto bail;
689 	}
690 
691 	mtx_lock(&Giant);
692 	error = vfs_domount(td, fstype, fspath, fsflags, optlist);
693 	mtx_unlock(&Giant);
694 bail:
695 	/* copyout the errmsg */
696 	if (errmsg_pos != -1 && ((2 * errmsg_pos + 1) < fsoptions->uio_iovcnt)
697 	    && errmsg_len > 0 && errmsg != NULL) {
698 		if (fsoptions->uio_segflg == UIO_SYSSPACE) {
699 			bcopy(errmsg,
700 			    fsoptions->uio_iov[2 * errmsg_pos + 1].iov_base,
701 			    fsoptions->uio_iov[2 * errmsg_pos + 1].iov_len);
702 		} else {
703 			copyout(errmsg,
704 			    fsoptions->uio_iov[2 * errmsg_pos + 1].iov_base,
705 			    fsoptions->uio_iov[2 * errmsg_pos + 1].iov_len);
706 		}
707 	}
708 
709 	if (error != 0)
710 		vfs_freeopts(optlist);
711 	return (error);
712 }
713 
714 /*
715  * ---------------------------------------------------------------------
716  * Old mount API.
717  */
718 #ifndef _SYS_SYSPROTO_H_
719 struct mount_args {
720 	char	*type;
721 	char	*path;
722 	int	flags;
723 	caddr_t	data;
724 };
725 #endif
726 /* ARGSUSED */
727 int
728 mount(td, uap)
729 	struct thread *td;
730 	struct mount_args /* {
731 		char *type;
732 		char *path;
733 		int flags;
734 		caddr_t data;
735 	} */ *uap;
736 {
737 	char *fstype;
738 	struct vfsconf *vfsp = NULL;
739 	struct mntarg *ma = NULL;
740 	int error;
741 
742 	AUDIT_ARG(fflags, uap->flags);
743 
744 	/* Kick out MNT_ROOTFS early as it is legal internally */
745 	uap->flags &= ~MNT_ROOTFS;
746 
747 	fstype = malloc(MFSNAMELEN, M_TEMP, M_WAITOK);
748 	error = copyinstr(uap->type, fstype, MFSNAMELEN, NULL);
749 	if (error) {
750 		free(fstype, M_TEMP);
751 		return (error);
752 	}
753 
754 	AUDIT_ARG(text, fstype);
755 	mtx_lock(&Giant);
756 	vfsp = vfs_byname_kld(fstype, td, &error);
757 	free(fstype, M_TEMP);
758 	if (vfsp == NULL) {
759 		mtx_unlock(&Giant);
760 		return (ENOENT);
761 	}
762 	if (vfsp->vfc_vfsops->vfs_cmount == NULL) {
763 		mtx_unlock(&Giant);
764 		return (EOPNOTSUPP);
765 	}
766 
767 	ma = mount_argsu(ma, "fstype", uap->type, MNAMELEN);
768 	ma = mount_argsu(ma, "fspath", uap->path, MNAMELEN);
769 	ma = mount_argb(ma, uap->flags & MNT_RDONLY, "noro");
770 	ma = mount_argb(ma, !(uap->flags & MNT_NOSUID), "nosuid");
771 	ma = mount_argb(ma, !(uap->flags & MNT_NOEXEC), "noexec");
772 
773 	error = vfsp->vfc_vfsops->vfs_cmount(ma, uap->data, uap->flags, td);
774 	mtx_unlock(&Giant);
775 	return (error);
776 }
777 
778 
779 /*
780  * vfs_domount(): actually attempt a filesystem mount.
781  */
782 static int
783 vfs_domount(
784 	struct thread *td,	/* Calling thread. */
785 	const char *fstype,	/* Filesystem type. */
786 	char *fspath,		/* Mount path. */
787 	int fsflags,		/* Flags common to all filesystems. */
788 	void *fsdata		/* Options local to the filesystem. */
789 	)
790 {
791 	struct vnode *vp;
792 	struct mount *mp;
793 	struct vfsconf *vfsp;
794 	struct export_args export;
795 	int error, flag = 0;
796 	struct vattr va;
797 	struct nameidata nd;
798 
799 	mtx_assert(&Giant, MA_OWNED);
800 	/*
801 	 * Be ultra-paranoid about making sure the type and fspath
802 	 * variables will fit in our mp buffers, including the
803 	 * terminating NUL.
804 	 */
805 	if (strlen(fstype) >= MFSNAMELEN || strlen(fspath) >= MNAMELEN)
806 		return (ENAMETOOLONG);
807 
808 	if (jailed(td->td_ucred))
809 		return (EPERM);
810 	if (usermount == 0) {
811 		if ((error = suser(td)) != 0)
812 			return (error);
813 	}
814 
815 	/*
816 	 * Do not allow NFS export or MNT_SUIDDIR by unprivileged users.
817 	 */
818 	if (fsflags & (MNT_EXPORTED | MNT_SUIDDIR)) {
819 		if ((error = suser(td)) != 0)
820 			return (error);
821 	}
822 	/*
823 	 * Silently enforce MNT_NOSUID and MNT_USER for
824 	 * unprivileged users.
825 	 */
826 	if (suser(td) != 0)
827 		fsflags |= MNT_NOSUID | MNT_USER;
828 
829 	/* Load KLDs before we lock the covered vnode to avoid reversals. */
830 	vfsp = NULL;
831 	if ((fsflags & MNT_UPDATE) == 0) {
832 		/* Don't try to load KLDs if we're mounting the root. */
833 		if (fsflags & MNT_ROOTFS)
834 			vfsp = vfs_byname(fstype);
835 		else
836 			vfsp = vfs_byname_kld(fstype, td, &error);
837 		if (vfsp == NULL)
838 			return (ENODEV);
839 	}
840 	/*
841 	 * Get vnode to be covered
842 	 */
843 	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNODE1, UIO_SYSSPACE,
844 	    fspath, td);
845 	if ((error = namei(&nd)) != 0)
846 		return (error);
847 	NDFREE(&nd, NDF_ONLY_PNBUF);
848 	vp = nd.ni_vp;
849 	if (fsflags & MNT_UPDATE) {
850 		if ((vp->v_vflag & VV_ROOT) == 0) {
851 			vput(vp);
852 			return (EINVAL);
853 		}
854 		mp = vp->v_mount;
855 		MNT_ILOCK(mp);
856 		flag = mp->mnt_flag;
857 		/*
858 		 * We only allow the filesystem to be reloaded if it
859 		 * is currently mounted read-only.
860 		 */
861 		if ((fsflags & MNT_RELOAD) &&
862 		    ((mp->mnt_flag & MNT_RDONLY) == 0)) {
863 			MNT_IUNLOCK(mp);
864 			vput(vp);
865 			return (EOPNOTSUPP);	/* Needs translation */
866 		}
867 		MNT_IUNLOCK(mp);
868 		/*
869 		 * Only privileged root, or (if MNT_USER is set) the user that
870 		 * did the original mount is permitted to update it.
871 		 */
872 		error = vfs_suser(mp, td);
873 		if (error) {
874 			vput(vp);
875 			return (error);
876 		}
877 		if (vfs_busy(mp, LK_NOWAIT, 0, td)) {
878 			vput(vp);
879 			return (EBUSY);
880 		}
881 		VI_LOCK(vp);
882 		if ((vp->v_iflag & VI_MOUNT) != 0 ||
883 		    vp->v_mountedhere != NULL) {
884 			VI_UNLOCK(vp);
885 			vfs_unbusy(mp, td);
886 			vput(vp);
887 			return (EBUSY);
888 		}
889 		vp->v_iflag |= VI_MOUNT;
890 		VI_UNLOCK(vp);
891 		MNT_ILOCK(mp);
892 		mp->mnt_flag |= fsflags &
893 		    (MNT_RELOAD | MNT_FORCE | MNT_UPDATE | MNT_SNAPSHOT | MNT_ROOTFS);
894 		MNT_IUNLOCK(mp);
895 		VOP_UNLOCK(vp, 0, td);
896 		mp->mnt_optnew = fsdata;
897 		vfs_mergeopts(mp->mnt_optnew, mp->mnt_opt);
898 	} else {
899 		/*
900 		 * If the user is not root, ensure that they own the directory
901 		 * onto which we are attempting to mount.
902 		 */
903 		error = VOP_GETATTR(vp, &va, td->td_ucred, td);
904 		if (error) {
905 			vput(vp);
906 			return (error);
907 		}
908 		if (va.va_uid != td->td_ucred->cr_uid) {
909 			if ((error = suser(td)) != 0) {
910 				vput(vp);
911 				return (error);
912 			}
913 		}
914 		error = vinvalbuf(vp, V_SAVE, td, 0, 0);
915 		if (error != 0) {
916 			vput(vp);
917 			return (error);
918 		}
919 		if (vp->v_type != VDIR) {
920 			vput(vp);
921 			return (ENOTDIR);
922 		}
923 		VI_LOCK(vp);
924 		if ((vp->v_iflag & VI_MOUNT) != 0 ||
925 		    vp->v_mountedhere != NULL) {
926 			VI_UNLOCK(vp);
927 			vput(vp);
928 			return (EBUSY);
929 		}
930 		vp->v_iflag |= VI_MOUNT;
931 		VI_UNLOCK(vp);
932 
933 		/*
934 		 * Allocate and initialize the filesystem.
935 		 */
936 		mp = vfs_mount_alloc(vp, vfsp, fspath, td);
937 		VOP_UNLOCK(vp, 0, td);
938 
939 		/* XXXMAC: pass to vfs_mount_alloc? */
940 		mp->mnt_optnew = fsdata;
941 	}
942 
943 	/*
944 	 * Set the mount level flags.
945 	 */
946 	MNT_ILOCK(mp);
947 	mp->mnt_flag = (mp->mnt_flag & ~MNT_UPDATEMASK) |
948 		(fsflags & (MNT_UPDATEMASK | MNT_FORCE | MNT_ROOTFS |
949 			    MNT_RDONLY));
950 	if ((mp->mnt_flag & MNT_ASYNC) == 0)
951 		mp->mnt_kern_flag &= ~MNTK_ASYNC;
952 	MNT_IUNLOCK(mp);
953 	/*
954 	 * Mount the filesystem.
955 	 * XXX The final recipients of VFS_MOUNT just overwrite the ndp they
956 	 * get.  No freeing of cn_pnbuf.
957 	 */
958         error = VFS_MOUNT(mp, td);
959 
960 	/*
961 	 * Process the export option only if we are
962 	 * updating mount options.
963 	 */
964 	if (!error && (fsflags & MNT_UPDATE)) {
965 		if (vfs_copyopt(mp->mnt_optnew, "export", &export,
966 		    sizeof(export)) == 0)
967 			error = vfs_export(mp, &export);
968 	}
969 
970 	if (!error) {
971 		if (mp->mnt_opt != NULL)
972 			vfs_freeopts(mp->mnt_opt);
973 		mp->mnt_opt = mp->mnt_optnew;
974 		(void)VFS_STATFS(mp, &mp->mnt_stat, td);
975 	}
976 	/*
977 	 * Prevent external consumers of mount options from reading
978 	 * mnt_optnew.
979 	*/
980 	mp->mnt_optnew = NULL;
981 	if (mp->mnt_flag & MNT_UPDATE) {
982 		MNT_ILOCK(mp);
983 		if (error)
984 			mp->mnt_flag = (mp->mnt_flag & MNT_QUOTA) |
985 				(flag & ~MNT_QUOTA);
986 		else
987 			mp->mnt_flag &=	~(MNT_UPDATE | MNT_RELOAD |
988 					  MNT_FORCE | MNT_SNAPSHOT);
989 		if ((mp->mnt_flag & MNT_ASYNC) != 0 && mp->mnt_noasync == 0)
990 			mp->mnt_kern_flag |= MNTK_ASYNC;
991 		else
992 			mp->mnt_kern_flag &= ~MNTK_ASYNC;
993 		MNT_IUNLOCK(mp);
994 		if ((mp->mnt_flag & MNT_RDONLY) == 0) {
995 			if (mp->mnt_syncer == NULL)
996 				error = vfs_allocate_syncvnode(mp);
997 		} else {
998 			if (mp->mnt_syncer != NULL)
999 				vrele(mp->mnt_syncer);
1000 			mp->mnt_syncer = NULL;
1001 		}
1002 		vfs_unbusy(mp, td);
1003 		VI_LOCK(vp);
1004 		vp->v_iflag &= ~VI_MOUNT;
1005 		VI_UNLOCK(vp);
1006 		vrele(vp);
1007 		return (error);
1008 	}
1009 	MNT_ILOCK(mp);
1010 	if ((mp->mnt_flag & MNT_ASYNC) != 0 && mp->mnt_noasync == 0)
1011 		mp->mnt_kern_flag |= MNTK_ASYNC;
1012 	else
1013 		mp->mnt_kern_flag &= ~MNTK_ASYNC;
1014 	MNT_IUNLOCK(mp);
1015 	vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
1016 	/*
1017 	 * Put the new filesystem on the mount list after root.
1018 	 */
1019 	cache_purge(vp);
1020 	if (!error) {
1021 		struct vnode *newdp;
1022 
1023 		VI_LOCK(vp);
1024 		vp->v_iflag &= ~VI_MOUNT;
1025 		VI_UNLOCK(vp);
1026 		vp->v_mountedhere = mp;
1027 		mtx_lock(&mountlist_mtx);
1028 		TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
1029 		mtx_unlock(&mountlist_mtx);
1030 		vfs_event_signal(NULL, VQ_MOUNT, 0);
1031 		if (VFS_ROOT(mp, LK_EXCLUSIVE, &newdp, td))
1032 			panic("mount: lost mount");
1033 		mountcheckdirs(vp, newdp);
1034 		vput(newdp);
1035 		VOP_UNLOCK(vp, 0, td);
1036 		if ((mp->mnt_flag & MNT_RDONLY) == 0)
1037 			error = vfs_allocate_syncvnode(mp);
1038 		vfs_unbusy(mp, td);
1039 		if (error)
1040 			vrele(vp);
1041 	} else {
1042 		VI_LOCK(vp);
1043 		vp->v_iflag &= ~VI_MOUNT;
1044 		VI_UNLOCK(vp);
1045 		vfs_unbusy(mp, td);
1046 		vfs_mount_destroy(mp);
1047 		vput(vp);
1048 	}
1049 	return (error);
1050 }
1051 
1052 /*
1053  * ---------------------------------------------------------------------
1054  * Unmount a filesystem.
1055  *
1056  * Note: unmount takes a path to the vnode mounted on as argument,
1057  * not special file (as before).
1058  */
1059 #ifndef _SYS_SYSPROTO_H_
1060 struct unmount_args {
1061 	char	*path;
1062 	int	flags;
1063 };
1064 #endif
1065 /* ARGSUSED */
1066 int
1067 unmount(td, uap)
1068 	struct thread *td;
1069 	register struct unmount_args /* {
1070 		char *path;
1071 		int flags;
1072 	} */ *uap;
1073 {
1074 	struct mount *mp;
1075 	char *pathbuf;
1076 	int error, id0, id1;
1077 
1078 	if (jailed(td->td_ucred))
1079 		return (EPERM);
1080 	if (usermount == 0) {
1081 		if ((error = suser(td)) != 0)
1082 			return (error);
1083 	}
1084 
1085 	pathbuf = malloc(MNAMELEN, M_TEMP, M_WAITOK);
1086 	error = copyinstr(uap->path, pathbuf, MNAMELEN, NULL);
1087 	if (error) {
1088 		free(pathbuf, M_TEMP);
1089 		return (error);
1090 	}
1091 	AUDIT_ARG(upath, td, pathbuf, ARG_UPATH1);
1092 	mtx_lock(&Giant);
1093 	if (uap->flags & MNT_BYFSID) {
1094 		/* Decode the filesystem ID. */
1095 		if (sscanf(pathbuf, "FSID:%d:%d", &id0, &id1) != 2) {
1096 			mtx_unlock(&Giant);
1097 			free(pathbuf, M_TEMP);
1098 			return (EINVAL);
1099 		}
1100 
1101 		mtx_lock(&mountlist_mtx);
1102 		TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
1103 			if (mp->mnt_stat.f_fsid.val[0] == id0 &&
1104 			    mp->mnt_stat.f_fsid.val[1] == id1)
1105 				break;
1106 		}
1107 		mtx_unlock(&mountlist_mtx);
1108 	} else {
1109 		mtx_lock(&mountlist_mtx);
1110 		TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
1111 			if (strcmp(mp->mnt_stat.f_mntonname, pathbuf) == 0)
1112 				break;
1113 		}
1114 		mtx_unlock(&mountlist_mtx);
1115 	}
1116 	free(pathbuf, M_TEMP);
1117 	if (mp == NULL) {
1118 		/*
1119 		 * Previously we returned ENOENT for a nonexistent path and
1120 		 * EINVAL for a non-mountpoint.  We cannot tell these apart
1121 		 * now, so in the !MNT_BYFSID case return the more likely
1122 		 * EINVAL for compatibility.
1123 		 */
1124 		mtx_unlock(&Giant);
1125 		return ((uap->flags & MNT_BYFSID) ? ENOENT : EINVAL);
1126 	}
1127 
1128 	/*
1129 	 * Don't allow unmounting the root filesystem.
1130 	 */
1131 	if (mp->mnt_flag & MNT_ROOTFS) {
1132 		mtx_unlock(&Giant);
1133 		return (EINVAL);
1134 	}
1135 	error = dounmount(mp, uap->flags, td);
1136 	mtx_unlock(&Giant);
1137 	return (error);
1138 }
1139 
1140 /*
1141  * Do the actual filesystem unmount.
1142  */
1143 int
1144 dounmount(mp, flags, td)
1145 	struct mount *mp;
1146 	int flags;
1147 	struct thread *td;
1148 {
1149 	struct vnode *coveredvp, *fsrootvp;
1150 	int error;
1151 	int async_flag;
1152 	int mnt_gen_r;
1153 
1154 	mtx_assert(&Giant, MA_OWNED);
1155 
1156 	if ((coveredvp = mp->mnt_vnodecovered) != NULL) {
1157 		mnt_gen_r = mp->mnt_gen;
1158 		VI_LOCK(coveredvp);
1159 		vholdl(coveredvp);
1160 		error = vn_lock(coveredvp, LK_EXCLUSIVE | LK_INTERLOCK, td);
1161 		vdrop(coveredvp);
1162 		/*
1163 		 * Check for mp being unmounted while waiting for the
1164 		 * covered vnode lock.
1165 		 */
1166 		if (error)
1167 			return (error);
1168 		if (coveredvp->v_mountedhere != mp ||
1169 		    coveredvp->v_mountedhere->mnt_gen != mnt_gen_r) {
1170 			VOP_UNLOCK(coveredvp, 0, td);
1171 			return (EBUSY);
1172 		}
1173 	}
1174 	/*
1175 	 * Only privileged root, or (if MNT_USER is set) the user that did the
1176 	 * original mount is permitted to unmount this filesystem.
1177 	 */
1178 	error = vfs_suser(mp, td);
1179 	if (error) {
1180 		if (coveredvp)
1181 			VOP_UNLOCK(coveredvp, 0, td);
1182 		return (error);
1183 	}
1184 
1185 	MNT_ILOCK(mp);
1186 	if (mp->mnt_kern_flag & MNTK_UNMOUNT) {
1187 		MNT_IUNLOCK(mp);
1188 		if (coveredvp)
1189 			VOP_UNLOCK(coveredvp, 0, td);
1190 		return (EBUSY);
1191 	}
1192 	mp->mnt_kern_flag |= MNTK_UNMOUNT;
1193 	/* Allow filesystems to detect that a forced unmount is in progress. */
1194 	if (flags & MNT_FORCE)
1195 		mp->mnt_kern_flag |= MNTK_UNMOUNTF;
1196 	error = lockmgr(&mp->mnt_lock, LK_DRAIN | LK_INTERLOCK |
1197 	    ((flags & MNT_FORCE) ? 0 : LK_NOWAIT), MNT_MTX(mp), td);
1198 	if (error) {
1199 		MNT_ILOCK(mp);
1200 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
1201 		if (mp->mnt_kern_flag & MNTK_MWAIT)
1202 			wakeup(mp);
1203 		MNT_IUNLOCK(mp);
1204 		if (coveredvp)
1205 			VOP_UNLOCK(coveredvp, 0, td);
1206 		return (error);
1207 	}
1208 	vn_start_write(NULL, &mp, V_WAIT);
1209 
1210 	if (mp->mnt_flag & MNT_EXPUBLIC)
1211 		vfs_setpublicfs(NULL, NULL, NULL);
1212 
1213 	vfs_msync(mp, MNT_WAIT);
1214 	MNT_ILOCK(mp);
1215 	async_flag = mp->mnt_flag & MNT_ASYNC;
1216 	mp->mnt_flag &= ~MNT_ASYNC;
1217 	mp->mnt_kern_flag &= ~MNTK_ASYNC;
1218 	MNT_IUNLOCK(mp);
1219 	cache_purgevfs(mp);	/* remove cache entries for this file sys */
1220 	if (mp->mnt_syncer != NULL)
1221 		vrele(mp->mnt_syncer);
1222 	/*
1223 	 * For forced unmounts, move process cdir/rdir refs on the fs root
1224 	 * vnode to the covered vnode.  For non-forced unmounts we want
1225 	 * such references to cause an EBUSY error.
1226 	 */
1227 	if ((flags & MNT_FORCE) &&
1228 	    VFS_ROOT(mp, LK_EXCLUSIVE, &fsrootvp, td) == 0) {
1229 		if (mp->mnt_vnodecovered != NULL)
1230 			mountcheckdirs(fsrootvp, mp->mnt_vnodecovered);
1231 		if (fsrootvp == rootvnode) {
1232 			vrele(rootvnode);
1233 			rootvnode = NULL;
1234 		}
1235 		vput(fsrootvp);
1236 	}
1237 	if (((mp->mnt_flag & MNT_RDONLY) ||
1238 	     (error = VFS_SYNC(mp, MNT_WAIT, td)) == 0) ||
1239 	    (flags & MNT_FORCE)) {
1240 		error = VFS_UNMOUNT(mp, flags, td);
1241 	}
1242 	vn_finished_write(mp);
1243 	if (error) {
1244 		/* Undo cdir/rdir and rootvnode changes made above. */
1245 		if ((flags & MNT_FORCE) &&
1246 		    VFS_ROOT(mp, LK_EXCLUSIVE, &fsrootvp, td) == 0) {
1247 			if (mp->mnt_vnodecovered != NULL)
1248 				mountcheckdirs(mp->mnt_vnodecovered, fsrootvp);
1249 			if (rootvnode == NULL) {
1250 				rootvnode = fsrootvp;
1251 				vref(rootvnode);
1252 			}
1253 			vput(fsrootvp);
1254 		}
1255 		if ((mp->mnt_flag & MNT_RDONLY) == 0 && mp->mnt_syncer == NULL)
1256 			(void) vfs_allocate_syncvnode(mp);
1257 		MNT_ILOCK(mp);
1258 		mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
1259 		mp->mnt_flag |= async_flag;
1260 		if ((mp->mnt_flag & MNT_ASYNC) != 0 && mp->mnt_noasync == 0)
1261 			mp->mnt_kern_flag |= MNTK_ASYNC;
1262 		lockmgr(&mp->mnt_lock, LK_RELEASE, NULL, td);
1263 		if (mp->mnt_kern_flag & MNTK_MWAIT)
1264 			wakeup(mp);
1265 		MNT_IUNLOCK(mp);
1266 		if (coveredvp)
1267 			VOP_UNLOCK(coveredvp, 0, td);
1268 		return (error);
1269 	}
1270 	mtx_lock(&mountlist_mtx);
1271 	TAILQ_REMOVE(&mountlist, mp, mnt_list);
1272 	mtx_unlock(&mountlist_mtx);
1273 	if (coveredvp != NULL) {
1274 		coveredvp->v_mountedhere = NULL;
1275 		vput(coveredvp);
1276 	}
1277 	vfs_event_signal(NULL, VQ_UNMOUNT, 0);
1278 	lockmgr(&mp->mnt_lock, LK_RELEASE, NULL, td);
1279 	vfs_mount_destroy(mp);
1280 	return (0);
1281 }
1282 
1283 /*
1284  * ---------------------------------------------------------------------
1285  * Mounting of root filesystem
1286  *
1287  */
1288 
1289 struct root_hold_token {
1290 	const char 			*who;
1291 	LIST_ENTRY(root_hold_token)	list;
1292 };
1293 
1294 static LIST_HEAD(, root_hold_token)	root_holds =
1295     LIST_HEAD_INITIALIZER(&root_holds);
1296 
1297 struct root_hold_token *
1298 root_mount_hold(const char *identifier)
1299 {
1300 	struct root_hold_token *h;
1301 
1302 	h = malloc(sizeof *h, M_DEVBUF, M_ZERO | M_WAITOK);
1303 	h->who = identifier;
1304 	mtx_lock(&mountlist_mtx);
1305 	LIST_INSERT_HEAD(&root_holds, h, list);
1306 	mtx_unlock(&mountlist_mtx);
1307 	return (h);
1308 }
1309 
1310 void
1311 root_mount_rel(struct root_hold_token *h)
1312 {
1313 
1314 	mtx_lock(&mountlist_mtx);
1315 	LIST_REMOVE(h, list);
1316 	wakeup(&root_holds);
1317 	mtx_unlock(&mountlist_mtx);
1318 	free(h, M_DEVBUF);
1319 }
1320 
1321 static void
1322 root_mount_wait(void)
1323 {
1324 	struct root_hold_token *h;
1325 
1326 	for (;;) {
1327 		DROP_GIANT();
1328 		g_waitidle();
1329 		PICKUP_GIANT();
1330 		mtx_lock(&mountlist_mtx);
1331 		if (LIST_EMPTY(&root_holds)) {
1332 			mtx_unlock(&mountlist_mtx);
1333 			break;
1334 		}
1335 		printf("Root mount waiting for:");
1336 		LIST_FOREACH(h, &root_holds, list)
1337 			printf(" %s", h->who);
1338 		printf("\n");
1339 		msleep(&root_holds, &mountlist_mtx, PZERO | PDROP, "roothold",
1340 		    hz);
1341 	}
1342 }
1343 
1344 static void
1345 set_rootvnode(struct thread *td)
1346 {
1347 	struct proc *p;
1348 
1349 	if (VFS_ROOT(TAILQ_FIRST(&mountlist), LK_EXCLUSIVE, &rootvnode, td))
1350 		panic("Cannot find root vnode");
1351 
1352 	p = td->td_proc;
1353 	FILEDESC_LOCK(p->p_fd);
1354 
1355 	if (p->p_fd->fd_cdir != NULL)
1356 		vrele(p->p_fd->fd_cdir);
1357 	p->p_fd->fd_cdir = rootvnode;
1358 	VREF(rootvnode);
1359 
1360 	if (p->p_fd->fd_rdir != NULL)
1361 		vrele(p->p_fd->fd_rdir);
1362 	p->p_fd->fd_rdir = rootvnode;
1363 	VREF(rootvnode);
1364 
1365 	FILEDESC_UNLOCK(p->p_fd);
1366 
1367 	VOP_UNLOCK(rootvnode, 0, td);
1368 }
1369 
1370 /*
1371  * Mount /devfs as our root filesystem, but do not put it on the mountlist
1372  * yet.  Create a /dev -> / symlink so that absolute pathnames will lookup.
1373  */
1374 
1375 static void
1376 devfs_first(void)
1377 {
1378 	struct thread *td = curthread;
1379 	struct vfsoptlist *opts;
1380 	struct vfsconf *vfsp;
1381 	struct mount *mp = NULL;
1382 	int error;
1383 
1384 	vfsp = vfs_byname("devfs");
1385 	KASSERT(vfsp != NULL, ("Could not find devfs by name"));
1386 	if (vfsp == NULL)
1387 		return;
1388 
1389 	mp = vfs_mount_alloc(NULLVP, vfsp, "/dev", td);
1390 
1391 	error = VFS_MOUNT(mp, td);
1392 	KASSERT(error == 0, ("VFS_MOUNT(devfs) failed %d", error));
1393 	if (error)
1394 		return;
1395 
1396 	opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
1397 	TAILQ_INIT(opts);
1398 	mp->mnt_opt = opts;
1399 
1400 	mtx_lock(&mountlist_mtx);
1401 	TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
1402 	mtx_unlock(&mountlist_mtx);
1403 
1404 	set_rootvnode(td);
1405 
1406 	error = kern_symlink(td, "/", "dev", UIO_SYSSPACE);
1407 	if (error)
1408 		printf("kern_symlink /dev -> / returns %d\n", error);
1409 }
1410 
1411 /*
1412  * Surgically move our devfs to be mounted on /dev.
1413  */
1414 
1415 static void
1416 devfs_fixup(struct thread *td)
1417 {
1418 	struct nameidata nd;
1419 	int error;
1420 	struct vnode *vp, *dvp;
1421 	struct mount *mp;
1422 
1423 	/* Remove our devfs mount from the mountlist and purge the cache */
1424 	mtx_lock(&mountlist_mtx);
1425 	mp = TAILQ_FIRST(&mountlist);
1426 	TAILQ_REMOVE(&mountlist, mp, mnt_list);
1427 	mtx_unlock(&mountlist_mtx);
1428 	cache_purgevfs(mp);
1429 
1430 	VFS_ROOT(mp, LK_EXCLUSIVE, &dvp, td);
1431 	VI_LOCK(dvp);
1432 	dvp->v_iflag &= ~VI_MOUNT;
1433 	dvp->v_mountedhere = NULL;
1434 	VI_UNLOCK(dvp);
1435 
1436 	/* Set up the real rootvnode, and purge the cache */
1437 	TAILQ_FIRST(&mountlist)->mnt_vnodecovered = NULL;
1438 	set_rootvnode(td);
1439 	cache_purgevfs(rootvnode->v_mount);
1440 
1441 	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, "/dev", td);
1442 	error = namei(&nd);
1443 	if (error) {
1444 		printf("Lookup of /dev for devfs, error: %d\n", error);
1445 		return;
1446 	}
1447 	NDFREE(&nd, NDF_ONLY_PNBUF);
1448 	vp = nd.ni_vp;
1449 	if (vp->v_type != VDIR) {
1450 		vput(vp);
1451 	}
1452 	error = vinvalbuf(vp, V_SAVE, td, 0, 0);
1453 	if (error) {
1454 		vput(vp);
1455 	}
1456 	cache_purge(vp);
1457 	mp->mnt_vnodecovered = vp;
1458 	vp->v_mountedhere = mp;
1459 	mtx_lock(&mountlist_mtx);
1460 	TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
1461 	mtx_unlock(&mountlist_mtx);
1462 	VOP_UNLOCK(vp, 0, td);
1463 	vput(dvp);
1464 	vfs_unbusy(mp, td);
1465 
1466 	/* Unlink the no longer needed /dev/dev -> / symlink */
1467 	kern_unlink(td, "/dev/dev", UIO_SYSSPACE);
1468 }
1469 
1470 /*
1471  * Report errors during filesystem mounting.
1472  */
1473 void
1474 vfs_mount_error(struct mount *mp, const char *fmt, ...)
1475 {
1476 	struct vfsoptlist *moptlist = mp->mnt_optnew;
1477 	va_list ap;
1478 	int error, len;
1479 	char *errmsg;
1480 
1481 	error = vfs_getopt(moptlist, "errmsg", (void **)&errmsg, &len);
1482 	if (error || errmsg == NULL || len <= 0)
1483 		return;
1484 
1485 	va_start(ap, fmt);
1486 	vsnprintf(errmsg, (size_t)len, fmt, ap);
1487 	va_end(ap);
1488 }
1489 
1490 /*
1491  * Find and mount the root filesystem
1492  */
1493 void
1494 vfs_mountroot(void)
1495 {
1496 	char *cp;
1497 	int error, i, asked = 0;
1498 
1499 	root_mount_wait();
1500 
1501 	mount_zone = uma_zcreate("Mountpoints", sizeof(struct mount),
1502 	    NULL, NULL, mount_init, mount_fini,
1503 	    UMA_ALIGN_PTR, UMA_ZONE_NOFREE);
1504 	devfs_first();
1505 
1506 	/*
1507 	 * We are booted with instructions to prompt for the root filesystem.
1508 	 */
1509 	if (boothowto & RB_ASKNAME) {
1510 		if (!vfs_mountroot_ask())
1511 			return;
1512 		asked = 1;
1513 	}
1514 
1515 	/*
1516 	 * The root filesystem information is compiled in, and we are
1517 	 * booted with instructions to use it.
1518 	 */
1519 	if (ctrootdevname != NULL && (boothowto & RB_DFLTROOT)) {
1520 		if (!vfs_mountroot_try(ctrootdevname))
1521 			return;
1522 		ctrootdevname = NULL;
1523 	}
1524 
1525 	/*
1526 	 * We've been given the generic "use CDROM as root" flag.  This is
1527 	 * necessary because one media may be used in many different
1528 	 * devices, so we need to search for them.
1529 	 */
1530 	if (boothowto & RB_CDROM) {
1531 		for (i = 0; cdrom_rootdevnames[i] != NULL; i++) {
1532 			if (!vfs_mountroot_try(cdrom_rootdevnames[i]))
1533 				return;
1534 		}
1535 	}
1536 
1537 	/*
1538 	 * Try to use the value read by the loader from /etc/fstab, or
1539 	 * supplied via some other means.  This is the preferred
1540 	 * mechanism.
1541 	 */
1542 	cp = getenv("vfs.root.mountfrom");
1543 	if (cp != NULL) {
1544 		error = vfs_mountroot_try(cp);
1545 		freeenv(cp);
1546 		if (!error)
1547 			return;
1548 	}
1549 
1550 	/*
1551 	 * Try values that may have been computed by code during boot
1552 	 */
1553 	if (!vfs_mountroot_try(rootdevnames[0]))
1554 		return;
1555 	if (!vfs_mountroot_try(rootdevnames[1]))
1556 		return;
1557 
1558 	/*
1559 	 * If we (still) have a compiled-in default, try it.
1560 	 */
1561 	if (ctrootdevname != NULL)
1562 		if (!vfs_mountroot_try(ctrootdevname))
1563 			return;
1564 	/*
1565 	 * Everything so far has failed, prompt on the console if we haven't
1566 	 * already tried that.
1567 	 */
1568 	if (!asked)
1569 		if (!vfs_mountroot_ask())
1570 			return;
1571 
1572 	panic("Root mount failed, startup aborted.");
1573 }
1574 
1575 /*
1576  * Mount (mountfrom) as the root filesystem.
1577  */
1578 static int
1579 vfs_mountroot_try(const char *mountfrom)
1580 {
1581 	struct mount	*mp;
1582 	char		*vfsname, *path;
1583 	time_t		timebase;
1584 	int		error;
1585 	char		patt[32];
1586 
1587 	vfsname = NULL;
1588 	path    = NULL;
1589 	mp      = NULL;
1590 	error   = EINVAL;
1591 
1592 	if (mountfrom == NULL)
1593 		return (error);		/* don't complain */
1594 	printf("Trying to mount root from %s\n", mountfrom);
1595 
1596 	/* parse vfs name and path */
1597 	vfsname = malloc(MFSNAMELEN, M_MOUNT, M_WAITOK);
1598 	path = malloc(MNAMELEN, M_MOUNT, M_WAITOK);
1599 	vfsname[0] = path[0] = 0;
1600 	sprintf(patt, "%%%d[a-z0-9]:%%%ds", MFSNAMELEN, MNAMELEN);
1601 	if (sscanf(mountfrom, patt, vfsname, path) < 1)
1602 		goto out;
1603 
1604 	if (path[0] == '\0')
1605 		strcpy(path, ROOTNAME);
1606 
1607 	error = kernel_vmount(
1608 	    MNT_RDONLY | MNT_ROOTFS,
1609 	    "fstype", vfsname,
1610 	    "fspath", "/",
1611 	    "from", path,
1612 	    NULL);
1613 	if (error == 0) {
1614 		/*
1615 		 * We mount devfs prior to mounting the / FS, so the first
1616 		 * entry will typically be devfs.
1617 		 */
1618 		mp = TAILQ_FIRST(&mountlist);
1619 		KASSERT(mp != NULL, ("%s: mountlist is empty", __func__));
1620 
1621 		/*
1622 		 * Iterate over all currently mounted file systems and use
1623 		 * the time stamp found to check and/or initialize the RTC.
1624 		 * Typically devfs has no time stamp and the only other FS
1625 		 * is the actual / FS.
1626 		 * Call inittodr() only once and pass it the largest of the
1627 		 * timestamps we encounter.
1628 		 */
1629 		timebase = 0;
1630 		do {
1631 			if (mp->mnt_time > timebase)
1632 				timebase = mp->mnt_time;
1633 			mp = TAILQ_NEXT(mp, mnt_list);
1634 		} while (mp != NULL);
1635 		inittodr(timebase);
1636 
1637 		devfs_fixup(curthread);
1638 	}
1639 out:
1640 	free(path, M_MOUNT);
1641 	free(vfsname, M_MOUNT);
1642 	return (error);
1643 }
1644 
1645 /*
1646  * ---------------------------------------------------------------------
1647  * Interactive root filesystem selection code.
1648  */
1649 
1650 static int
1651 vfs_mountroot_ask(void)
1652 {
1653 	char name[128];
1654 
1655 	for(;;) {
1656 		printf("\nManual root filesystem specification:\n");
1657 		printf("  <fstype>:<device>  Mount <device> using filesystem <fstype>\n");
1658 #if defined(__amd64__) || defined(__i386__) || defined(__ia64__)
1659 		printf("                       eg. ufs:da0s1a\n");
1660 #else
1661 		printf("                       eg. ufs:/dev/da0a\n");
1662 #endif
1663 		printf("  ?                  List valid disk boot devices\n");
1664 		printf("  <empty line>       Abort manual input\n");
1665 		printf("\nmountroot> ");
1666 		gets(name, sizeof(name), 1);
1667 		if (name[0] == '\0')
1668 			return (1);
1669 		if (name[0] == '?') {
1670 			printf("\nList of GEOM managed disk devices:\n  ");
1671 			g_dev_print();
1672 			continue;
1673 		}
1674 		if (!vfs_mountroot_try(name))
1675 			return (0);
1676 	}
1677 }
1678 
1679 /*
1680  * ---------------------------------------------------------------------
1681  * Functions for querying mount options/arguments from filesystems.
1682  */
1683 
1684 /*
1685  * Check that no unknown options are given
1686  */
1687 int
1688 vfs_filteropt(struct vfsoptlist *opts, const char **legal)
1689 {
1690 	struct vfsopt *opt;
1691 	const char **t, *p;
1692 
1693 
1694 	TAILQ_FOREACH(opt, opts, link) {
1695 		p = opt->name;
1696 		if (p[0] == 'n' && p[1] == 'o')
1697 			p += 2;
1698 		for(t = global_opts; *t != NULL; t++)
1699 			if (!strcmp(*t, p))
1700 				break;
1701 		if (*t != NULL)
1702 			continue;
1703 		for(t = legal; *t != NULL; t++)
1704 			if (!strcmp(*t, p))
1705 				break;
1706 		if (*t != NULL)
1707 			continue;
1708 		printf("mount option <%s> is unknown\n", p);
1709 		return (EINVAL);
1710 	}
1711 	return (0);
1712 }
1713 
1714 /*
1715  * Get a mount option by its name.
1716  *
1717  * Return 0 if the option was found, ENOENT otherwise.
1718  * If len is non-NULL it will be filled with the length
1719  * of the option. If buf is non-NULL, it will be filled
1720  * with the address of the option.
1721  */
1722 int
1723 vfs_getopt(opts, name, buf, len)
1724 	struct vfsoptlist *opts;
1725 	const char *name;
1726 	void **buf;
1727 	int *len;
1728 {
1729 	struct vfsopt *opt;
1730 
1731 	KASSERT(opts != NULL, ("vfs_getopt: caller passed 'opts' as NULL"));
1732 
1733 	TAILQ_FOREACH(opt, opts, link) {
1734 		if (strcmp(name, opt->name) == 0) {
1735 			if (len != NULL)
1736 				*len = opt->len;
1737 			if (buf != NULL)
1738 				*buf = opt->value;
1739 			return (0);
1740 		}
1741 	}
1742 	return (ENOENT);
1743 }
1744 
1745 static int
1746 vfs_getopt_pos(struct vfsoptlist *opts, const char *name)
1747 {
1748 	struct vfsopt *opt;
1749 	int i;
1750 
1751 	if (opts == NULL)
1752 		return (-1);
1753 
1754 	i = 0;
1755 	TAILQ_FOREACH(opt, opts, link) {
1756 		if (strcmp(name, opt->name) == 0)
1757 			return (i);
1758 		++i;
1759 	}
1760 	return (-1);
1761 }
1762 
1763 char *
1764 vfs_getopts(struct vfsoptlist *opts, const char *name, int *error)
1765 {
1766 	struct vfsopt *opt;
1767 
1768 	*error = 0;
1769 	TAILQ_FOREACH(opt, opts, link) {
1770 		if (strcmp(name, opt->name) != 0)
1771 			continue;
1772 		if (((char *)opt->value)[opt->len - 1] != '\0') {
1773 			*error = EINVAL;
1774 			return (NULL);
1775 		}
1776 		return (opt->value);
1777 	}
1778 	return (NULL);
1779 }
1780 
1781 int
1782 vfs_flagopt(struct vfsoptlist *opts, const char *name, u_int *w, u_int val)
1783 {
1784 	struct vfsopt *opt;
1785 
1786 	TAILQ_FOREACH(opt, opts, link) {
1787 		if (strcmp(name, opt->name) == 0) {
1788 			if (w != NULL)
1789 				*w |= val;
1790 			return (1);
1791 		}
1792 	}
1793 	if (w != NULL)
1794 		*w &= ~val;
1795 	return (0);
1796 }
1797 
1798 int
1799 vfs_scanopt(struct vfsoptlist *opts, const char *name, const char *fmt, ...)
1800 {
1801 	va_list ap;
1802 	struct vfsopt *opt;
1803 	int ret;
1804 
1805 	KASSERT(opts != NULL, ("vfs_getopt: caller passed 'opts' as NULL"));
1806 
1807 	TAILQ_FOREACH(opt, opts, link) {
1808 		if (strcmp(name, opt->name) != 0)
1809 			continue;
1810 		if (((char *)opt->value)[opt->len - 1] != '\0')
1811 			return (0);
1812 		va_start(ap, fmt);
1813 		ret = vsscanf(opt->value, fmt, ap);
1814 		va_end(ap);
1815 		return (ret);
1816 	}
1817 	return (0);
1818 }
1819 
1820 /*
1821  * Find and copy a mount option.
1822  *
1823  * The size of the buffer has to be specified
1824  * in len, if it is not the same length as the
1825  * mount option, EINVAL is returned.
1826  * Returns ENOENT if the option is not found.
1827  */
1828 int
1829 vfs_copyopt(opts, name, dest, len)
1830 	struct vfsoptlist *opts;
1831 	const char *name;
1832 	void *dest;
1833 	int len;
1834 {
1835 	struct vfsopt *opt;
1836 
1837 	KASSERT(opts != NULL, ("vfs_copyopt: caller passed 'opts' as NULL"));
1838 
1839 	TAILQ_FOREACH(opt, opts, link) {
1840 		if (strcmp(name, opt->name) == 0) {
1841 			if (len != opt->len)
1842 				return (EINVAL);
1843 			bcopy(opt->value, dest, opt->len);
1844 			return (0);
1845 		}
1846 	}
1847 	return (ENOENT);
1848 }
1849 
1850 /*
1851  * This is a helper function for filesystems to traverse their
1852  * vnodes.  See MNT_VNODE_FOREACH() in sys/mount.h
1853  */
1854 
1855 struct vnode *
1856 __mnt_vnode_next(struct vnode **mvp, struct mount *mp)
1857 {
1858 	struct vnode *vp;
1859 
1860 	mtx_assert(MNT_MTX(mp), MA_OWNED);
1861 
1862 	KASSERT((*mvp)->v_mount == mp, ("marker vnode mount list mismatch"));
1863 	vp = TAILQ_NEXT(*mvp, v_nmntvnodes);
1864 	while (vp != NULL && vp->v_type == VMARKER)
1865 		vp = TAILQ_NEXT(vp, v_nmntvnodes);
1866 
1867 	/* Check if we are done */
1868 	if (vp == NULL) {
1869 		__mnt_vnode_markerfree(mvp, mp);
1870 		return (NULL);
1871 	}
1872 	TAILQ_REMOVE(&mp->mnt_nvnodelist, *mvp, v_nmntvnodes);
1873 	TAILQ_INSERT_AFTER(&mp->mnt_nvnodelist, vp, *mvp, v_nmntvnodes);
1874 	return (vp);
1875 }
1876 
1877 struct vnode *
1878 __mnt_vnode_first(struct vnode **mvp, struct mount *mp)
1879 {
1880 	struct vnode *vp;
1881 
1882 	mtx_assert(MNT_MTX(mp), MA_OWNED);
1883 
1884 	vp = TAILQ_FIRST(&mp->mnt_nvnodelist);
1885 	while (vp != NULL && vp->v_type == VMARKER)
1886 		vp = TAILQ_NEXT(vp, v_nmntvnodes);
1887 
1888 	/* Check if we are done */
1889 	if (vp == NULL) {
1890 		*mvp = NULL;
1891 		return (NULL);
1892 	}
1893 	mp->mnt_holdcnt++;
1894 	MNT_IUNLOCK(mp);
1895 	*mvp = (struct vnode *) malloc(sizeof(struct vnode),
1896 				       M_VNODE_MARKER,
1897 				       M_WAITOK | M_ZERO);
1898 	MNT_ILOCK(mp);
1899 	(*mvp)->v_type = VMARKER;
1900 
1901 	vp = TAILQ_FIRST(&mp->mnt_nvnodelist);
1902 	while (vp != NULL && vp->v_type == VMARKER)
1903 		vp = TAILQ_NEXT(vp, v_nmntvnodes);
1904 
1905 	/* Check if we are done */
1906 	if (vp == NULL) {
1907 		MNT_IUNLOCK(mp);
1908 		free(*mvp, M_VNODE_MARKER);
1909 		MNT_ILOCK(mp);
1910 		*mvp = NULL;
1911 		mp->mnt_holdcnt--;
1912 		if (mp->mnt_holdcnt == 0 && mp->mnt_holdcntwaiters != 0)
1913 			wakeup(&mp->mnt_holdcnt);
1914 		return (NULL);
1915 	}
1916 	mp->mnt_markercnt++;
1917 	(*mvp)->v_mount = mp;
1918 	TAILQ_INSERT_AFTER(&mp->mnt_nvnodelist, vp, *mvp, v_nmntvnodes);
1919 	return (vp);
1920 }
1921 
1922 
1923 void
1924 __mnt_vnode_markerfree(struct vnode **mvp, struct mount *mp)
1925 {
1926 
1927 	if (*mvp == NULL)
1928 		return;
1929 
1930 	mtx_assert(MNT_MTX(mp), MA_OWNED);
1931 
1932 	KASSERT((*mvp)->v_mount == mp, ("marker vnode mount list mismatch"));
1933 	TAILQ_REMOVE(&mp->mnt_nvnodelist, *mvp, v_nmntvnodes);
1934 	MNT_IUNLOCK(mp);
1935 	free(*mvp, M_VNODE_MARKER);
1936 	MNT_ILOCK(mp);
1937 	*mvp = NULL;
1938 
1939 	mp->mnt_markercnt--;
1940 	mp->mnt_holdcnt--;
1941 	if (mp->mnt_holdcnt == 0 && mp->mnt_holdcntwaiters != 0)
1942 		wakeup(&mp->mnt_holdcnt);
1943 }
1944 
1945 
1946 int
1947 __vfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *td)
1948 {
1949 	int error;
1950 
1951 	error = mp->mnt_op->vfs_statfs(mp, &mp->mnt_stat, td);
1952 	if (sbp != &mp->mnt_stat)
1953 		*sbp = mp->mnt_stat;
1954 	return (error);
1955 }
1956 
1957 void
1958 vfs_mountedfrom(struct mount *mp, const char *from)
1959 {
1960 
1961 	bzero(mp->mnt_stat.f_mntfromname, sizeof mp->mnt_stat.f_mntfromname);
1962 	strlcpy(mp->mnt_stat.f_mntfromname, from,
1963 	    sizeof mp->mnt_stat.f_mntfromname);
1964 }
1965 
1966 /*
1967  * ---------------------------------------------------------------------
1968  * This is the api for building mount args and mounting filesystems from
1969  * inside the kernel.
1970  *
1971  * The API works by accumulation of individual args.  First error is
1972  * latched.
1973  *
1974  * XXX: should be documented in new manpage kernel_mount(9)
1975  */
1976 
1977 /* A memory allocation which must be freed when we are done */
1978 struct mntaarg {
1979 	SLIST_ENTRY(mntaarg)	next;
1980 };
1981 
1982 /* The header for the mount arguments */
1983 struct mntarg {
1984 	struct iovec *v;
1985 	int len;
1986 	int error;
1987 	SLIST_HEAD(, mntaarg)	list;
1988 };
1989 
1990 /*
1991  * Add a boolean argument.
1992  *
1993  * flag is the boolean value.
1994  * name must start with "no".
1995  */
1996 struct mntarg *
1997 mount_argb(struct mntarg *ma, int flag, const char *name)
1998 {
1999 
2000 	KASSERT(name[0] == 'n' && name[1] == 'o',
2001 	    ("mount_argb(...,%s): name must start with 'no'", name));
2002 
2003 	return (mount_arg(ma, name + (flag ? 2 : 0), NULL, 0));
2004 }
2005 
2006 /*
2007  * Add an argument printf style
2008  */
2009 struct mntarg *
2010 mount_argf(struct mntarg *ma, const char *name, const char *fmt, ...)
2011 {
2012 	va_list ap;
2013 	struct mntaarg *maa;
2014 	struct sbuf *sb;
2015 	int len;
2016 
2017 	if (ma == NULL) {
2018 		ma = malloc(sizeof *ma, M_MOUNT, M_WAITOK | M_ZERO);
2019 		SLIST_INIT(&ma->list);
2020 	}
2021 	if (ma->error)
2022 		return (ma);
2023 
2024 	ma->v = realloc(ma->v, sizeof *ma->v * (ma->len + 2),
2025 	    M_MOUNT, M_WAITOK);
2026 	ma->v[ma->len].iov_base = (void *)(uintptr_t)name;
2027 	ma->v[ma->len].iov_len = strlen(name) + 1;
2028 	ma->len++;
2029 
2030 	sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND);
2031 	va_start(ap, fmt);
2032 	sbuf_vprintf(sb, fmt, ap);
2033 	va_end(ap);
2034 	sbuf_finish(sb);
2035 	len = sbuf_len(sb) + 1;
2036 	maa = malloc(sizeof *maa + len, M_MOUNT, M_WAITOK | M_ZERO);
2037 	SLIST_INSERT_HEAD(&ma->list, maa, next);
2038 	bcopy(sbuf_data(sb), maa + 1, len);
2039 	sbuf_delete(sb);
2040 
2041 	ma->v[ma->len].iov_base = maa + 1;
2042 	ma->v[ma->len].iov_len = len;
2043 	ma->len++;
2044 
2045 	return (ma);
2046 }
2047 
2048 /*
2049  * Add an argument which is a userland string.
2050  */
2051 struct mntarg *
2052 mount_argsu(struct mntarg *ma, const char *name, const void *val, int len)
2053 {
2054 	struct mntaarg *maa;
2055 	char *tbuf;
2056 
2057 	if (val == NULL)
2058 		return (ma);
2059 	if (ma == NULL) {
2060 		ma = malloc(sizeof *ma, M_MOUNT, M_WAITOK | M_ZERO);
2061 		SLIST_INIT(&ma->list);
2062 	}
2063 	if (ma->error)
2064 		return (ma);
2065 	maa = malloc(sizeof *maa + len, M_MOUNT, M_WAITOK | M_ZERO);
2066 	SLIST_INSERT_HEAD(&ma->list, maa, next);
2067 	tbuf = (void *)(maa + 1);
2068 	ma->error = copyinstr(val, tbuf, len, NULL);
2069 	return (mount_arg(ma, name, tbuf, -1));
2070 }
2071 
2072 /*
2073  * Plain argument.
2074  *
2075  * If length is -1, use printf.
2076  */
2077 struct mntarg *
2078 mount_arg(struct mntarg *ma, const char *name, const void *val, int len)
2079 {
2080 
2081 	if (ma == NULL) {
2082 		ma = malloc(sizeof *ma, M_MOUNT, M_WAITOK | M_ZERO);
2083 		SLIST_INIT(&ma->list);
2084 	}
2085 	if (ma->error)
2086 		return (ma);
2087 
2088 	ma->v = realloc(ma->v, sizeof *ma->v * (ma->len + 2),
2089 	    M_MOUNT, M_WAITOK);
2090 	ma->v[ma->len].iov_base = (void *)(uintptr_t)name;
2091 	ma->v[ma->len].iov_len = strlen(name) + 1;
2092 	ma->len++;
2093 
2094 	ma->v[ma->len].iov_base = (void *)(uintptr_t)val;
2095 	if (len < 0)
2096 		ma->v[ma->len].iov_len = strlen(val) + 1;
2097 	else
2098 		ma->v[ma->len].iov_len = len;
2099 	ma->len++;
2100 	return (ma);
2101 }
2102 
2103 /*
2104  * Free a mntarg structure
2105  */
2106 static void
2107 free_mntarg(struct mntarg *ma)
2108 {
2109 	struct mntaarg *maa;
2110 
2111 	while (!SLIST_EMPTY(&ma->list)) {
2112 		maa = SLIST_FIRST(&ma->list);
2113 		SLIST_REMOVE_HEAD(&ma->list, next);
2114 		free(maa, M_MOUNT);
2115 	}
2116 	free(ma->v, M_MOUNT);
2117 	free(ma, M_MOUNT);
2118 }
2119 
2120 /*
2121  * Mount a filesystem
2122  */
2123 int
2124 kernel_mount(struct mntarg *ma, int flags)
2125 {
2126 	struct uio auio;
2127 	int error;
2128 
2129 	KASSERT(ma != NULL, ("kernel_mount NULL ma"));
2130 	KASSERT(ma->v != NULL, ("kernel_mount NULL ma->v"));
2131 	KASSERT(!(ma->len & 1), ("kernel_mount odd ma->len (%d)", ma->len));
2132 
2133 	auio.uio_iov = ma->v;
2134 	auio.uio_iovcnt = ma->len;
2135 	auio.uio_segflg = UIO_SYSSPACE;
2136 
2137 	error = ma->error;
2138 	if (!error)
2139 		error = vfs_donmount(curthread, flags, &auio);
2140 	free_mntarg(ma);
2141 	return (error);
2142 }
2143 
2144 /*
2145  * A printflike function to mount a filesystem.
2146  */
2147 int
2148 kernel_vmount(int flags, ...)
2149 {
2150 	struct mntarg *ma = NULL;
2151 	va_list ap;
2152 	const char *cp;
2153 	const void *vp;
2154 	int error;
2155 
2156 	va_start(ap, flags);
2157 	for (;;) {
2158 		cp = va_arg(ap, const char *);
2159 		if (cp == NULL)
2160 			break;
2161 		vp = va_arg(ap, const void *);
2162 		ma = mount_arg(ma, cp, vp, -1);
2163 	}
2164 	va_end(ap);
2165 
2166 	error = kernel_mount(ma, flags);
2167 	return (error);
2168 }
2169