1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1999-2004 Poul-Henning Kamp
5 * Copyright (c) 1999 Michael Smith
6 * Copyright (c) 1989, 1993
7 * The Regents of the University of California. All rights reserved.
8 * (c) UNIX System Laboratories, Inc.
9 * All or some portions of this file are derived from material licensed
10 * to the University of California by American Telephone and Telegraph
11 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
12 * the permission of UNIX System Laboratories, Inc.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 * 3. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 */
38
39 #include <sys/param.h>
40 #include <sys/conf.h>
41 #include <sys/smp.h>
42 #include <sys/devctl.h>
43 #include <sys/eventhandler.h>
44 #include <sys/fcntl.h>
45 #include <sys/jail.h>
46 #include <sys/kernel.h>
47 #include <sys/ktr.h>
48 #include <sys/libkern.h>
49 #include <sys/limits.h>
50 #include <sys/malloc.h>
51 #include <sys/mount.h>
52 #include <sys/mutex.h>
53 #include <sys/namei.h>
54 #include <sys/priv.h>
55 #include <sys/proc.h>
56 #include <sys/filedesc.h>
57 #include <sys/reboot.h>
58 #include <sys/sbuf.h>
59 #include <sys/syscallsubr.h>
60 #include <sys/sysproto.h>
61 #include <sys/sx.h>
62 #include <sys/sysctl.h>
63 #include <sys/systm.h>
64 #include <sys/taskqueue.h>
65 #include <sys/vnode.h>
66 #include <vm/uma.h>
67
68 #include <geom/geom.h>
69
70 #include <machine/stdarg.h>
71
72 #include <security/audit/audit.h>
73 #include <security/mac/mac_framework.h>
74
75 #define VFS_MOUNTARG_SIZE_MAX (1024 * 64)
76
77 static int vfs_domount(struct thread *td, const char *fstype, char *fspath,
78 uint64_t fsflags, bool jail_export,
79 struct vfsoptlist **optlist);
80 static void free_mntarg(struct mntarg *ma);
81
82 static int usermount = 0;
83 SYSCTL_INT(_vfs, OID_AUTO, usermount, CTLFLAG_RW, &usermount, 0,
84 "Unprivileged users may mount and unmount file systems");
85
86 static bool default_autoro = false;
87 SYSCTL_BOOL(_vfs, OID_AUTO, default_autoro, CTLFLAG_RW, &default_autoro, 0,
88 "Retry failed r/w mount as r/o if no explicit ro/rw option is specified");
89
90 static bool recursive_forced_unmount = false;
91 SYSCTL_BOOL(_vfs, OID_AUTO, recursive_forced_unmount, CTLFLAG_RW,
92 &recursive_forced_unmount, 0, "Recursively unmount stacked upper mounts"
93 " when a file system is forcibly unmounted");
94
95 static SYSCTL_NODE(_vfs, OID_AUTO, deferred_unmount,
96 CTLFLAG_RD | CTLFLAG_MPSAFE, 0, "deferred unmount controls");
97
98 static unsigned int deferred_unmount_retry_limit = 10;
99 SYSCTL_UINT(_vfs_deferred_unmount, OID_AUTO, retry_limit, CTLFLAG_RW,
100 &deferred_unmount_retry_limit, 0,
101 "Maximum number of retries for deferred unmount failure");
102
103 static int deferred_unmount_retry_delay_hz;
104 SYSCTL_INT(_vfs_deferred_unmount, OID_AUTO, retry_delay_hz, CTLFLAG_RW,
105 &deferred_unmount_retry_delay_hz, 0,
106 "Delay in units of [1/kern.hz]s when retrying a failed deferred unmount");
107
108 static int deferred_unmount_total_retries = 0;
109 SYSCTL_INT(_vfs_deferred_unmount, OID_AUTO, total_retries, CTLFLAG_RD,
110 &deferred_unmount_total_retries, 0,
111 "Total number of retried deferred unmounts");
112
113 MALLOC_DEFINE(M_MOUNT, "mount", "vfs mount structure");
114 MALLOC_DEFINE(M_STATFS, "statfs", "statfs structure");
115 static uma_zone_t mount_zone;
116
117 /* List of mounted filesystems. */
118 struct mntlist mountlist = TAILQ_HEAD_INITIALIZER(mountlist);
119
120 /* For any iteration/modification of mountlist */
121 struct mtx_padalign __exclusive_cache_line mountlist_mtx;
122
123 EVENTHANDLER_LIST_DEFINE(vfs_mounted);
124 EVENTHANDLER_LIST_DEFINE(vfs_unmounted);
125
126 static void vfs_deferred_unmount(void *arg, int pending);
127 static struct timeout_task deferred_unmount_task;
128 static struct mtx deferred_unmount_lock;
129 MTX_SYSINIT(deferred_unmount, &deferred_unmount_lock, "deferred_unmount",
130 MTX_DEF);
131 static STAILQ_HEAD(, mount) deferred_unmount_list =
132 STAILQ_HEAD_INITIALIZER(deferred_unmount_list);
133 TASKQUEUE_DEFINE_THREAD(deferred_unmount);
134
135 static void mount_devctl_event(const char *type, struct mount *mp, bool donew);
136
137 /*
138 * Global opts, taken by all filesystems
139 */
140 static const char *global_opts[] = {
141 "errmsg",
142 "fstype",
143 "fspath",
144 "ro",
145 "rw",
146 "nosuid",
147 "noexec",
148 NULL
149 };
150
151 static int
mount_init(void * mem,int size,int flags)152 mount_init(void *mem, int size, int flags)
153 {
154 struct mount *mp;
155
156 mp = (struct mount *)mem;
157 mtx_init(&mp->mnt_mtx, "struct mount mtx", NULL, MTX_DEF);
158 mtx_init(&mp->mnt_listmtx, "struct mount vlist mtx", NULL, MTX_DEF);
159 lockinit(&mp->mnt_explock, PVFS, "explock", 0, 0);
160 mp->mnt_pcpu = uma_zalloc_pcpu(pcpu_zone_16, M_WAITOK | M_ZERO);
161 mp->mnt_ref = 0;
162 mp->mnt_vfs_ops = 1;
163 mp->mnt_rootvnode = NULL;
164 return (0);
165 }
166
167 static void
mount_fini(void * mem,int size)168 mount_fini(void *mem, int size)
169 {
170 struct mount *mp;
171
172 mp = (struct mount *)mem;
173 uma_zfree_pcpu(pcpu_zone_16, mp->mnt_pcpu);
174 lockdestroy(&mp->mnt_explock);
175 mtx_destroy(&mp->mnt_listmtx);
176 mtx_destroy(&mp->mnt_mtx);
177 }
178
179 static void
vfs_mount_init(void * dummy __unused)180 vfs_mount_init(void *dummy __unused)
181 {
182 TIMEOUT_TASK_INIT(taskqueue_deferred_unmount, &deferred_unmount_task,
183 0, vfs_deferred_unmount, NULL);
184 deferred_unmount_retry_delay_hz = hz;
185 mount_zone = uma_zcreate("Mountpoints", sizeof(struct mount), NULL,
186 NULL, mount_init, mount_fini, UMA_ALIGN_CACHE, UMA_ZONE_NOFREE);
187 mtx_init(&mountlist_mtx, "mountlist", NULL, MTX_DEF);
188 }
189 SYSINIT(vfs_mount, SI_SUB_VFS, SI_ORDER_ANY, vfs_mount_init, NULL);
190
191 /*
192 * ---------------------------------------------------------------------
193 * Functions for building and sanitizing the mount options
194 */
195
196 /* Remove one mount option. */
197 static void
vfs_freeopt(struct vfsoptlist * opts,struct vfsopt * opt)198 vfs_freeopt(struct vfsoptlist *opts, struct vfsopt *opt)
199 {
200
201 TAILQ_REMOVE(opts, opt, link);
202 free(opt->name, M_MOUNT);
203 if (opt->value != NULL)
204 free(opt->value, M_MOUNT);
205 free(opt, M_MOUNT);
206 }
207
208 /* Release all resources related to the mount options. */
209 void
vfs_freeopts(struct vfsoptlist * opts)210 vfs_freeopts(struct vfsoptlist *opts)
211 {
212 struct vfsopt *opt;
213
214 while (!TAILQ_EMPTY(opts)) {
215 opt = TAILQ_FIRST(opts);
216 vfs_freeopt(opts, opt);
217 }
218 free(opts, M_MOUNT);
219 }
220
221 void
vfs_deleteopt(struct vfsoptlist * opts,const char * name)222 vfs_deleteopt(struct vfsoptlist *opts, const char *name)
223 {
224 struct vfsopt *opt, *temp;
225
226 if (opts == NULL)
227 return;
228 TAILQ_FOREACH_SAFE(opt, opts, link, temp) {
229 if (strcmp(opt->name, name) == 0)
230 vfs_freeopt(opts, opt);
231 }
232 }
233
234 static int
vfs_isopt_ro(const char * opt)235 vfs_isopt_ro(const char *opt)
236 {
237
238 if (strcmp(opt, "ro") == 0 || strcmp(opt, "rdonly") == 0 ||
239 strcmp(opt, "norw") == 0)
240 return (1);
241 return (0);
242 }
243
244 static int
vfs_isopt_rw(const char * opt)245 vfs_isopt_rw(const char *opt)
246 {
247
248 if (strcmp(opt, "rw") == 0 || strcmp(opt, "noro") == 0)
249 return (1);
250 return (0);
251 }
252
253 /*
254 * Check if options are equal (with or without the "no" prefix).
255 */
256 static int
vfs_equalopts(const char * opt1,const char * opt2)257 vfs_equalopts(const char *opt1, const char *opt2)
258 {
259 char *p;
260
261 /* "opt" vs. "opt" or "noopt" vs. "noopt" */
262 if (strcmp(opt1, opt2) == 0)
263 return (1);
264 /* "noopt" vs. "opt" */
265 if (strncmp(opt1, "no", 2) == 0 && strcmp(opt1 + 2, opt2) == 0)
266 return (1);
267 /* "opt" vs. "noopt" */
268 if (strncmp(opt2, "no", 2) == 0 && strcmp(opt1, opt2 + 2) == 0)
269 return (1);
270 while ((p = strchr(opt1, '.')) != NULL &&
271 !strncmp(opt1, opt2, ++p - opt1)) {
272 opt2 += p - opt1;
273 opt1 = p;
274 /* "foo.noopt" vs. "foo.opt" */
275 if (strncmp(opt1, "no", 2) == 0 && strcmp(opt1 + 2, opt2) == 0)
276 return (1);
277 /* "foo.opt" vs. "foo.noopt" */
278 if (strncmp(opt2, "no", 2) == 0 && strcmp(opt1, opt2 + 2) == 0)
279 return (1);
280 }
281 /* "ro" / "rdonly" / "norw" / "rw" / "noro" */
282 if ((vfs_isopt_ro(opt1) || vfs_isopt_rw(opt1)) &&
283 (vfs_isopt_ro(opt2) || vfs_isopt_rw(opt2)))
284 return (1);
285 return (0);
286 }
287
288 /*
289 * If a mount option is specified several times,
290 * (with or without the "no" prefix) only keep
291 * the last occurrence of it.
292 */
293 static void
vfs_sanitizeopts(struct vfsoptlist * opts)294 vfs_sanitizeopts(struct vfsoptlist *opts)
295 {
296 struct vfsopt *opt, *opt2, *tmp;
297
298 TAILQ_FOREACH_REVERSE(opt, opts, vfsoptlist, link) {
299 opt2 = TAILQ_PREV(opt, vfsoptlist, link);
300 while (opt2 != NULL) {
301 if (vfs_equalopts(opt->name, opt2->name)) {
302 tmp = TAILQ_PREV(opt2, vfsoptlist, link);
303 vfs_freeopt(opts, opt2);
304 opt2 = tmp;
305 } else {
306 opt2 = TAILQ_PREV(opt2, vfsoptlist, link);
307 }
308 }
309 }
310 }
311
312 /*
313 * Build a linked list of mount options from a struct uio.
314 */
315 int
vfs_buildopts(struct uio * auio,struct vfsoptlist ** options)316 vfs_buildopts(struct uio *auio, struct vfsoptlist **options)
317 {
318 struct vfsoptlist *opts;
319 struct vfsopt *opt;
320 size_t memused, namelen, optlen;
321 unsigned int i, iovcnt;
322 int error;
323
324 opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
325 TAILQ_INIT(opts);
326 memused = 0;
327 iovcnt = auio->uio_iovcnt;
328 for (i = 0; i < iovcnt; i += 2) {
329 namelen = auio->uio_iov[i].iov_len;
330 optlen = auio->uio_iov[i + 1].iov_len;
331 memused += sizeof(struct vfsopt) + optlen + namelen;
332 /*
333 * Avoid consuming too much memory, and attempts to overflow
334 * memused.
335 */
336 if (memused > VFS_MOUNTARG_SIZE_MAX ||
337 optlen > VFS_MOUNTARG_SIZE_MAX ||
338 namelen > VFS_MOUNTARG_SIZE_MAX) {
339 error = EINVAL;
340 goto bad;
341 }
342
343 opt = malloc(sizeof(struct vfsopt), M_MOUNT, M_WAITOK);
344 opt->name = malloc(namelen, M_MOUNT, M_WAITOK);
345 opt->value = NULL;
346 opt->len = 0;
347 opt->pos = i / 2;
348 opt->seen = 0;
349
350 /*
351 * Do this early, so jumps to "bad" will free the current
352 * option.
353 */
354 TAILQ_INSERT_TAIL(opts, opt, link);
355
356 if (auio->uio_segflg == UIO_SYSSPACE) {
357 bcopy(auio->uio_iov[i].iov_base, opt->name, namelen);
358 } else {
359 error = copyin(auio->uio_iov[i].iov_base, opt->name,
360 namelen);
361 if (error)
362 goto bad;
363 }
364 /* Ensure names are null-terminated strings. */
365 if (namelen == 0 || opt->name[namelen - 1] != '\0') {
366 error = EINVAL;
367 goto bad;
368 }
369 if (optlen != 0) {
370 opt->len = optlen;
371 opt->value = malloc(optlen, M_MOUNT, M_WAITOK);
372 if (auio->uio_segflg == UIO_SYSSPACE) {
373 bcopy(auio->uio_iov[i + 1].iov_base, opt->value,
374 optlen);
375 } else {
376 error = copyin(auio->uio_iov[i + 1].iov_base,
377 opt->value, optlen);
378 if (error)
379 goto bad;
380 }
381 }
382 }
383 vfs_sanitizeopts(opts);
384 *options = opts;
385 return (0);
386 bad:
387 vfs_freeopts(opts);
388 return (error);
389 }
390
391 /*
392 * Merge the old mount options with the new ones passed
393 * in the MNT_UPDATE case.
394 *
395 * XXX: This function will keep a "nofoo" option in the new
396 * options. E.g, if the option's canonical name is "foo",
397 * "nofoo" ends up in the mount point's active options.
398 */
399 static void
vfs_mergeopts(struct vfsoptlist * toopts,struct vfsoptlist * oldopts)400 vfs_mergeopts(struct vfsoptlist *toopts, struct vfsoptlist *oldopts)
401 {
402 struct vfsopt *opt, *new;
403
404 TAILQ_FOREACH(opt, oldopts, link) {
405 new = malloc(sizeof(struct vfsopt), M_MOUNT, M_WAITOK);
406 new->name = strdup(opt->name, M_MOUNT);
407 if (opt->len != 0) {
408 new->value = malloc(opt->len, M_MOUNT, M_WAITOK);
409 bcopy(opt->value, new->value, opt->len);
410 } else
411 new->value = NULL;
412 new->len = opt->len;
413 new->seen = opt->seen;
414 TAILQ_INSERT_HEAD(toopts, new, link);
415 }
416 vfs_sanitizeopts(toopts);
417 }
418
419 /*
420 * Mount a filesystem.
421 */
422 #ifndef _SYS_SYSPROTO_H_
423 struct nmount_args {
424 struct iovec *iovp;
425 unsigned int iovcnt;
426 int flags;
427 };
428 #endif
429 int
sys_nmount(struct thread * td,struct nmount_args * uap)430 sys_nmount(struct thread *td, struct nmount_args *uap)
431 {
432 struct uio *auio;
433 int error;
434 u_int iovcnt;
435 uint64_t flags;
436
437 /*
438 * Mount flags are now 64-bits. On 32-bit archtectures only
439 * 32-bits are passed in, but from here on everything handles
440 * 64-bit flags correctly.
441 */
442 flags = uap->flags;
443
444 AUDIT_ARG_FFLAGS(flags);
445 CTR4(KTR_VFS, "%s: iovp %p with iovcnt %d and flags %d", __func__,
446 uap->iovp, uap->iovcnt, flags);
447
448 /*
449 * Filter out MNT_ROOTFS. We do not want clients of nmount() in
450 * userspace to set this flag, but we must filter it out if we want
451 * MNT_UPDATE on the root file system to work.
452 * MNT_ROOTFS should only be set by the kernel when mounting its
453 * root file system.
454 */
455 flags &= ~MNT_ROOTFS;
456
457 iovcnt = uap->iovcnt;
458 /*
459 * Check that we have an even number of iovec's
460 * and that we have at least two options.
461 */
462 if ((iovcnt & 1) || (iovcnt < 4)) {
463 CTR2(KTR_VFS, "%s: failed for invalid iovcnt %d", __func__,
464 uap->iovcnt);
465 return (EINVAL);
466 }
467
468 error = copyinuio(uap->iovp, iovcnt, &auio);
469 if (error) {
470 CTR2(KTR_VFS, "%s: failed for invalid uio op with %d errno",
471 __func__, error);
472 return (error);
473 }
474 error = vfs_donmount(td, flags, auio);
475
476 freeuio(auio);
477 return (error);
478 }
479
480 /*
481 * ---------------------------------------------------------------------
482 * Various utility functions
483 */
484
485 /*
486 * Get a reference on a mount point from a vnode.
487 *
488 * The vnode is allowed to be passed unlocked and race against dooming. Note in
489 * such case there are no guarantees the referenced mount point will still be
490 * associated with it after the function returns.
491 */
492 struct mount *
vfs_ref_from_vp(struct vnode * vp)493 vfs_ref_from_vp(struct vnode *vp)
494 {
495 struct mount *mp;
496 struct mount_pcpu *mpcpu;
497
498 mp = atomic_load_ptr(&vp->v_mount);
499 if (__predict_false(mp == NULL)) {
500 return (mp);
501 }
502 if (vfs_op_thread_enter(mp, mpcpu)) {
503 if (__predict_true(mp == vp->v_mount)) {
504 vfs_mp_count_add_pcpu(mpcpu, ref, 1);
505 vfs_op_thread_exit(mp, mpcpu);
506 } else {
507 vfs_op_thread_exit(mp, mpcpu);
508 mp = NULL;
509 }
510 } else {
511 MNT_ILOCK(mp);
512 if (mp == vp->v_mount) {
513 MNT_REF(mp);
514 MNT_IUNLOCK(mp);
515 } else {
516 MNT_IUNLOCK(mp);
517 mp = NULL;
518 }
519 }
520 return (mp);
521 }
522
523 void
vfs_ref(struct mount * mp)524 vfs_ref(struct mount *mp)
525 {
526 struct mount_pcpu *mpcpu;
527
528 CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
529 if (vfs_op_thread_enter(mp, mpcpu)) {
530 vfs_mp_count_add_pcpu(mpcpu, ref, 1);
531 vfs_op_thread_exit(mp, mpcpu);
532 return;
533 }
534
535 MNT_ILOCK(mp);
536 MNT_REF(mp);
537 MNT_IUNLOCK(mp);
538 }
539
540 /*
541 * Register ump as an upper mount of the mount associated with
542 * vnode vp. This registration will be tracked through
543 * mount_upper_node upper, which should be allocated by the
544 * caller and stored in per-mount data associated with mp.
545 *
546 * If successful, this function will return the mount associated
547 * with vp, and will ensure that it cannot be unmounted until
548 * ump has been unregistered as one of its upper mounts.
549 *
550 * Upon failure this function will return NULL.
551 */
552 struct mount *
vfs_register_upper_from_vp(struct vnode * vp,struct mount * ump,struct mount_upper_node * upper)553 vfs_register_upper_from_vp(struct vnode *vp, struct mount *ump,
554 struct mount_upper_node *upper)
555 {
556 struct mount *mp;
557
558 mp = atomic_load_ptr(&vp->v_mount);
559 if (mp == NULL)
560 return (NULL);
561 MNT_ILOCK(mp);
562 if (mp != vp->v_mount ||
563 ((mp->mnt_kern_flag & (MNTK_UNMOUNT | MNTK_RECURSE)) != 0)) {
564 MNT_IUNLOCK(mp);
565 return (NULL);
566 }
567 KASSERT(ump != mp, ("upper and lower mounts are identical"));
568 upper->mp = ump;
569 MNT_REF(mp);
570 TAILQ_INSERT_TAIL(&mp->mnt_uppers, upper, mnt_upper_link);
571 MNT_IUNLOCK(mp);
572 return (mp);
573 }
574
575 /*
576 * Register upper mount ump to receive vnode unlink/reclaim
577 * notifications from lower mount mp. This registration will
578 * be tracked through mount_upper_node upper, which should be
579 * allocated by the caller and stored in per-mount data
580 * associated with mp.
581 *
582 * ump must already be registered as an upper mount of mp
583 * through a call to vfs_register_upper_from_vp().
584 */
585 void
vfs_register_for_notification(struct mount * mp,struct mount * ump,struct mount_upper_node * upper)586 vfs_register_for_notification(struct mount *mp, struct mount *ump,
587 struct mount_upper_node *upper)
588 {
589 upper->mp = ump;
590 MNT_ILOCK(mp);
591 TAILQ_INSERT_TAIL(&mp->mnt_notify, upper, mnt_upper_link);
592 MNT_IUNLOCK(mp);
593 }
594
595 static void
vfs_drain_upper_locked(struct mount * mp)596 vfs_drain_upper_locked(struct mount *mp)
597 {
598 mtx_assert(MNT_MTX(mp), MA_OWNED);
599 while (mp->mnt_upper_pending != 0) {
600 mp->mnt_kern_flag |= MNTK_UPPER_WAITER;
601 msleep(&mp->mnt_uppers, MNT_MTX(mp), 0, "mntupw", 0);
602 }
603 }
604
605 /*
606 * Undo a previous call to vfs_register_for_notification().
607 * The mount represented by upper must be currently registered
608 * as an upper mount for mp.
609 */
610 void
vfs_unregister_for_notification(struct mount * mp,struct mount_upper_node * upper)611 vfs_unregister_for_notification(struct mount *mp,
612 struct mount_upper_node *upper)
613 {
614 MNT_ILOCK(mp);
615 vfs_drain_upper_locked(mp);
616 TAILQ_REMOVE(&mp->mnt_notify, upper, mnt_upper_link);
617 MNT_IUNLOCK(mp);
618 }
619
620 /*
621 * Undo a previous call to vfs_register_upper_from_vp().
622 * This must be done before mp can be unmounted.
623 */
624 void
vfs_unregister_upper(struct mount * mp,struct mount_upper_node * upper)625 vfs_unregister_upper(struct mount *mp, struct mount_upper_node *upper)
626 {
627 MNT_ILOCK(mp);
628 KASSERT((mp->mnt_kern_flag & MNTK_UNMOUNT) == 0,
629 ("registered upper with pending unmount"));
630 vfs_drain_upper_locked(mp);
631 TAILQ_REMOVE(&mp->mnt_uppers, upper, mnt_upper_link);
632 if ((mp->mnt_kern_flag & MNTK_TASKQUEUE_WAITER) != 0 &&
633 TAILQ_EMPTY(&mp->mnt_uppers)) {
634 mp->mnt_kern_flag &= ~MNTK_TASKQUEUE_WAITER;
635 wakeup(&mp->mnt_taskqueue_link);
636 }
637 MNT_REL(mp);
638 MNT_IUNLOCK(mp);
639 }
640
641 void
vfs_rel(struct mount * mp)642 vfs_rel(struct mount *mp)
643 {
644 struct mount_pcpu *mpcpu;
645
646 CTR2(KTR_VFS, "%s: mp %p", __func__, mp);
647 if (vfs_op_thread_enter(mp, mpcpu)) {
648 vfs_mp_count_sub_pcpu(mpcpu, ref, 1);
649 vfs_op_thread_exit(mp, mpcpu);
650 return;
651 }
652
653 MNT_ILOCK(mp);
654 MNT_REL(mp);
655 MNT_IUNLOCK(mp);
656 }
657
658 /*
659 * Allocate and initialize the mount point struct.
660 */
661 struct mount *
vfs_mount_alloc(struct vnode * vp,struct vfsconf * vfsp,const char * fspath,struct ucred * cred)662 vfs_mount_alloc(struct vnode *vp, struct vfsconf *vfsp, const char *fspath,
663 struct ucred *cred)
664 {
665 struct mount *mp;
666
667 mp = uma_zalloc(mount_zone, M_WAITOK);
668 bzero(&mp->mnt_startzero,
669 __rangeof(struct mount, mnt_startzero, mnt_endzero));
670 mp->mnt_kern_flag = 0;
671 mp->mnt_flag = 0;
672 mp->mnt_rootvnode = NULL;
673 mp->mnt_vnodecovered = NULL;
674 mp->mnt_op = NULL;
675 mp->mnt_vfc = NULL;
676 TAILQ_INIT(&mp->mnt_nvnodelist);
677 mp->mnt_nvnodelistsize = 0;
678 TAILQ_INIT(&mp->mnt_lazyvnodelist);
679 mp->mnt_lazyvnodelistsize = 0;
680 MPPASS(mp->mnt_ref == 0 && mp->mnt_lockref == 0 &&
681 mp->mnt_writeopcount == 0, mp);
682 MPASSERT(mp->mnt_vfs_ops == 1, mp,
683 ("vfs_ops should be 1 but %d found", mp->mnt_vfs_ops));
684 (void) vfs_busy(mp, MBF_NOWAIT);
685 atomic_add_acq_int(&vfsp->vfc_refcount, 1);
686 mp->mnt_op = vfsp->vfc_vfsops;
687 mp->mnt_vfc = vfsp;
688 mp->mnt_stat.f_type = vfsp->vfc_typenum;
689 mp->mnt_gen++;
690 strlcpy(mp->mnt_stat.f_fstypename, vfsp->vfc_name, MFSNAMELEN);
691 mp->mnt_vnodecovered = vp;
692 mp->mnt_cred = crdup(cred);
693 mp->mnt_stat.f_owner = cred->cr_uid;
694 strlcpy(mp->mnt_stat.f_mntonname, fspath, MNAMELEN);
695 mp->mnt_iosize_max = DFLTPHYS;
696 #ifdef MAC
697 mac_mount_init(mp);
698 mac_mount_create(cred, mp);
699 #endif
700 arc4rand(&mp->mnt_hashseed, sizeof mp->mnt_hashseed, 0);
701 mp->mnt_upper_pending = 0;
702 TAILQ_INIT(&mp->mnt_uppers);
703 TAILQ_INIT(&mp->mnt_notify);
704 mp->mnt_taskqueue_flags = 0;
705 mp->mnt_unmount_retries = 0;
706 return (mp);
707 }
708
709 /*
710 * Destroy the mount struct previously allocated by vfs_mount_alloc().
711 */
712 void
vfs_mount_destroy(struct mount * mp)713 vfs_mount_destroy(struct mount *mp)
714 {
715
716 MPPASS(mp->mnt_vfs_ops != 0, mp);
717
718 vfs_assert_mount_counters(mp);
719
720 MNT_ILOCK(mp);
721 mp->mnt_kern_flag |= MNTK_REFEXPIRE;
722 if (mp->mnt_kern_flag & MNTK_MWAIT) {
723 mp->mnt_kern_flag &= ~MNTK_MWAIT;
724 wakeup(mp);
725 }
726 while (mp->mnt_ref)
727 msleep(mp, MNT_MTX(mp), PVFS, "mntref", 0);
728 KASSERT(mp->mnt_ref == 0,
729 ("%s: invalid refcount in the drain path @ %s:%d", __func__,
730 __FILE__, __LINE__));
731 MPPASS(mp->mnt_writeopcount == 0, mp);
732 MPPASS(mp->mnt_secondary_writes == 0, mp);
733 atomic_subtract_rel_int(&mp->mnt_vfc->vfc_refcount, 1);
734 if (!TAILQ_EMPTY(&mp->mnt_nvnodelist)) {
735 struct vnode *vp;
736
737 TAILQ_FOREACH(vp, &mp->mnt_nvnodelist, v_nmntvnodes)
738 vn_printf(vp, "dangling vnode ");
739 panic("unmount: dangling vnode");
740 }
741 KASSERT(mp->mnt_upper_pending == 0, ("mnt_upper_pending"));
742 KASSERT(TAILQ_EMPTY(&mp->mnt_uppers), ("mnt_uppers"));
743 KASSERT(TAILQ_EMPTY(&mp->mnt_notify), ("mnt_notify"));
744 MPPASS(mp->mnt_nvnodelistsize == 0, mp);
745 MPPASS(mp->mnt_lazyvnodelistsize == 0, mp);
746 MPPASS(mp->mnt_lockref == 0, mp);
747 MNT_IUNLOCK(mp);
748
749 MPASSERT(mp->mnt_vfs_ops == 1, mp,
750 ("vfs_ops should be 1 but %d found", mp->mnt_vfs_ops));
751
752 MPASSERT(mp->mnt_rootvnode == NULL, mp,
753 ("mount point still has a root vnode %p", mp->mnt_rootvnode));
754
755 if (mp->mnt_vnodecovered != NULL)
756 vrele(mp->mnt_vnodecovered);
757 #ifdef MAC
758 mac_mount_destroy(mp);
759 #endif
760 if (mp->mnt_opt != NULL)
761 vfs_freeopts(mp->mnt_opt);
762 if (mp->mnt_exjail != NULL) {
763 atomic_subtract_int(&mp->mnt_exjail->cr_prison->pr_exportcnt,
764 1);
765 crfree(mp->mnt_exjail);
766 }
767 if (mp->mnt_export != NULL) {
768 vfs_free_addrlist(mp->mnt_export);
769 free(mp->mnt_export, M_MOUNT);
770 }
771 crfree(mp->mnt_cred);
772 uma_zfree(mount_zone, mp);
773 }
774
775 static bool
vfs_should_downgrade_to_ro_mount(uint64_t fsflags,int error)776 vfs_should_downgrade_to_ro_mount(uint64_t fsflags, int error)
777 {
778 /* This is an upgrade of an exisiting mount. */
779 if ((fsflags & MNT_UPDATE) != 0)
780 return (false);
781 /* This is already an R/O mount. */
782 if ((fsflags & MNT_RDONLY) != 0)
783 return (false);
784
785 switch (error) {
786 case ENODEV: /* generic, geom, ... */
787 case EACCES: /* cam/scsi, ... */
788 case EROFS: /* md, mmcsd, ... */
789 /*
790 * These errors can be returned by the storage layer to signal
791 * that the media is read-only. No harm in the R/O mount
792 * attempt if the error was returned for some other reason.
793 */
794 return (true);
795 default:
796 return (false);
797 }
798 }
799
800 int
vfs_donmount(struct thread * td,uint64_t fsflags,struct uio * fsoptions)801 vfs_donmount(struct thread *td, uint64_t fsflags, struct uio *fsoptions)
802 {
803 struct vfsoptlist *optlist;
804 struct vfsopt *opt, *tmp_opt;
805 char *fstype, *fspath, *errmsg;
806 int error, fstypelen, fspathlen, errmsg_len, errmsg_pos;
807 bool autoro, has_nonexport, jail_export;
808
809 errmsg = fspath = NULL;
810 errmsg_len = fspathlen = 0;
811 errmsg_pos = -1;
812 autoro = default_autoro;
813
814 error = vfs_buildopts(fsoptions, &optlist);
815 if (error)
816 return (error);
817
818 if (vfs_getopt(optlist, "errmsg", (void **)&errmsg, &errmsg_len) == 0)
819 errmsg_pos = vfs_getopt_pos(optlist, "errmsg");
820
821 /*
822 * We need these two options before the others,
823 * and they are mandatory for any filesystem.
824 * Ensure they are NUL terminated as well.
825 */
826 fstypelen = 0;
827 error = vfs_getopt(optlist, "fstype", (void **)&fstype, &fstypelen);
828 if (error || fstypelen <= 0 || fstype[fstypelen - 1] != '\0') {
829 error = EINVAL;
830 if (errmsg != NULL)
831 strncpy(errmsg, "Invalid fstype", errmsg_len);
832 goto bail;
833 }
834 fspathlen = 0;
835 error = vfs_getopt(optlist, "fspath", (void **)&fspath, &fspathlen);
836 if (error || fspathlen <= 0 || fspath[fspathlen - 1] != '\0') {
837 error = EINVAL;
838 if (errmsg != NULL)
839 strncpy(errmsg, "Invalid fspath", errmsg_len);
840 goto bail;
841 }
842
843 /*
844 * Check to see that "export" is only used with the "update", "fstype",
845 * "fspath", "from" and "errmsg" options when in a vnet jail.
846 * These are the ones used to set/update exports by mountd(8).
847 * If only the above options are set in a jail that can run mountd(8),
848 * then the jail_export argument of vfs_domount() will be true.
849 * When jail_export is true, the vfs_suser() check does not cause
850 * failure, but limits the update to exports only.
851 * This allows mountd(8) running within the vnet jail
852 * to export file systems visible within the jail, but
853 * mounted outside of the jail.
854 */
855 /*
856 * We need to see if we have the "update" option
857 * before we call vfs_domount(), since vfs_domount() has special
858 * logic based on MNT_UPDATE. This is very important
859 * when we want to update the root filesystem.
860 */
861 has_nonexport = false;
862 jail_export = false;
863 TAILQ_FOREACH_SAFE(opt, optlist, link, tmp_opt) {
864 int do_freeopt = 0;
865
866 if (jailed(td->td_ucred) &&
867 strcmp(opt->name, "export") != 0 &&
868 strcmp(opt->name, "update") != 0 &&
869 strcmp(opt->name, "fstype") != 0 &&
870 strcmp(opt->name, "fspath") != 0 &&
871 strcmp(opt->name, "from") != 0 &&
872 strcmp(opt->name, "errmsg") != 0)
873 has_nonexport = true;
874 if (strcmp(opt->name, "update") == 0) {
875 fsflags |= MNT_UPDATE;
876 do_freeopt = 1;
877 }
878 else if (strcmp(opt->name, "async") == 0)
879 fsflags |= MNT_ASYNC;
880 else if (strcmp(opt->name, "force") == 0) {
881 fsflags |= MNT_FORCE;
882 do_freeopt = 1;
883 }
884 else if (strcmp(opt->name, "reload") == 0) {
885 fsflags |= MNT_RELOAD;
886 do_freeopt = 1;
887 }
888 else if (strcmp(opt->name, "multilabel") == 0)
889 fsflags |= MNT_MULTILABEL;
890 else if (strcmp(opt->name, "noasync") == 0)
891 fsflags &= ~MNT_ASYNC;
892 else if (strcmp(opt->name, "noatime") == 0)
893 fsflags |= MNT_NOATIME;
894 else if (strcmp(opt->name, "atime") == 0) {
895 free(opt->name, M_MOUNT);
896 opt->name = strdup("nonoatime", M_MOUNT);
897 }
898 else if (strcmp(opt->name, "noclusterr") == 0)
899 fsflags |= MNT_NOCLUSTERR;
900 else if (strcmp(opt->name, "clusterr") == 0) {
901 free(opt->name, M_MOUNT);
902 opt->name = strdup("nonoclusterr", M_MOUNT);
903 }
904 else if (strcmp(opt->name, "noclusterw") == 0)
905 fsflags |= MNT_NOCLUSTERW;
906 else if (strcmp(opt->name, "clusterw") == 0) {
907 free(opt->name, M_MOUNT);
908 opt->name = strdup("nonoclusterw", M_MOUNT);
909 }
910 else if (strcmp(opt->name, "noexec") == 0)
911 fsflags |= MNT_NOEXEC;
912 else if (strcmp(opt->name, "exec") == 0) {
913 free(opt->name, M_MOUNT);
914 opt->name = strdup("nonoexec", M_MOUNT);
915 }
916 else if (strcmp(opt->name, "nosuid") == 0)
917 fsflags |= MNT_NOSUID;
918 else if (strcmp(opt->name, "suid") == 0) {
919 free(opt->name, M_MOUNT);
920 opt->name = strdup("nonosuid", M_MOUNT);
921 }
922 else if (strcmp(opt->name, "nosymfollow") == 0)
923 fsflags |= MNT_NOSYMFOLLOW;
924 else if (strcmp(opt->name, "symfollow") == 0) {
925 free(opt->name, M_MOUNT);
926 opt->name = strdup("nonosymfollow", M_MOUNT);
927 }
928 else if (strcmp(opt->name, "noro") == 0) {
929 fsflags &= ~MNT_RDONLY;
930 autoro = false;
931 }
932 else if (strcmp(opt->name, "rw") == 0) {
933 fsflags &= ~MNT_RDONLY;
934 autoro = false;
935 }
936 else if (strcmp(opt->name, "ro") == 0) {
937 fsflags |= MNT_RDONLY;
938 autoro = false;
939 }
940 else if (strcmp(opt->name, "rdonly") == 0) {
941 free(opt->name, M_MOUNT);
942 opt->name = strdup("ro", M_MOUNT);
943 fsflags |= MNT_RDONLY;
944 autoro = false;
945 }
946 else if (strcmp(opt->name, "autoro") == 0) {
947 do_freeopt = 1;
948 autoro = true;
949 }
950 else if (strcmp(opt->name, "suiddir") == 0)
951 fsflags |= MNT_SUIDDIR;
952 else if (strcmp(opt->name, "sync") == 0)
953 fsflags |= MNT_SYNCHRONOUS;
954 else if (strcmp(opt->name, "union") == 0)
955 fsflags |= MNT_UNION;
956 else if (strcmp(opt->name, "export") == 0) {
957 fsflags |= MNT_EXPORTED;
958 jail_export = true;
959 } else if (strcmp(opt->name, "automounted") == 0) {
960 fsflags |= MNT_AUTOMOUNTED;
961 do_freeopt = 1;
962 } else if (strcmp(opt->name, "nocover") == 0) {
963 fsflags |= MNT_NOCOVER;
964 do_freeopt = 1;
965 } else if (strcmp(opt->name, "cover") == 0) {
966 fsflags &= ~MNT_NOCOVER;
967 do_freeopt = 1;
968 } else if (strcmp(opt->name, "emptydir") == 0) {
969 fsflags |= MNT_EMPTYDIR;
970 do_freeopt = 1;
971 } else if (strcmp(opt->name, "noemptydir") == 0) {
972 fsflags &= ~MNT_EMPTYDIR;
973 do_freeopt = 1;
974 }
975 if (do_freeopt)
976 vfs_freeopt(optlist, opt);
977 }
978
979 /*
980 * Be ultra-paranoid about making sure the type and fspath
981 * variables will fit in our mp buffers, including the
982 * terminating NUL.
983 */
984 if (fstypelen > MFSNAMELEN || fspathlen > MNAMELEN) {
985 error = ENAMETOOLONG;
986 goto bail;
987 }
988
989 /*
990 * If has_nonexport is true or the caller is not running within a
991 * vnet prison that can run mountd(8), set jail_export false.
992 */
993 if (has_nonexport || !jailed(td->td_ucred) ||
994 !prison_check_nfsd(td->td_ucred))
995 jail_export = false;
996
997 error = vfs_domount(td, fstype, fspath, fsflags, jail_export, &optlist);
998 if (error == ENODEV) {
999 error = EINVAL;
1000 if (errmsg != NULL)
1001 strncpy(errmsg, "Invalid fstype", errmsg_len);
1002 goto bail;
1003 }
1004
1005 /*
1006 * See if we can mount in the read-only mode if the error code suggests
1007 * that it could be possible and the mount options allow for that.
1008 * Never try it if "[no]{ro|rw}" has been explicitly requested and not
1009 * overridden by "autoro".
1010 */
1011 if (autoro && vfs_should_downgrade_to_ro_mount(fsflags, error)) {
1012 printf("%s: R/W mount failed, possibly R/O media,"
1013 " trying R/O mount\n", __func__);
1014 fsflags |= MNT_RDONLY;
1015 error = vfs_domount(td, fstype, fspath, fsflags, jail_export,
1016 &optlist);
1017 }
1018 bail:
1019 /* copyout the errmsg */
1020 if (errmsg_pos != -1 && ((2 * errmsg_pos + 1) < fsoptions->uio_iovcnt)
1021 && errmsg_len > 0 && errmsg != NULL) {
1022 if (fsoptions->uio_segflg == UIO_SYSSPACE) {
1023 bcopy(errmsg,
1024 fsoptions->uio_iov[2 * errmsg_pos + 1].iov_base,
1025 fsoptions->uio_iov[2 * errmsg_pos + 1].iov_len);
1026 } else {
1027 (void)copyout(errmsg,
1028 fsoptions->uio_iov[2 * errmsg_pos + 1].iov_base,
1029 fsoptions->uio_iov[2 * errmsg_pos + 1].iov_len);
1030 }
1031 }
1032
1033 if (optlist != NULL)
1034 vfs_freeopts(optlist);
1035 return (error);
1036 }
1037
1038 /*
1039 * Old mount API.
1040 */
1041 #ifndef _SYS_SYSPROTO_H_
1042 struct mount_args {
1043 char *type;
1044 char *path;
1045 int flags;
1046 caddr_t data;
1047 };
1048 #endif
1049 /* ARGSUSED */
1050 int
sys_mount(struct thread * td,struct mount_args * uap)1051 sys_mount(struct thread *td, struct mount_args *uap)
1052 {
1053 char *fstype;
1054 struct vfsconf *vfsp = NULL;
1055 struct mntarg *ma = NULL;
1056 uint64_t flags;
1057 int error;
1058
1059 /*
1060 * Mount flags are now 64-bits. On 32-bit architectures only
1061 * 32-bits are passed in, but from here on everything handles
1062 * 64-bit flags correctly.
1063 */
1064 flags = uap->flags;
1065
1066 AUDIT_ARG_FFLAGS(flags);
1067
1068 /*
1069 * Filter out MNT_ROOTFS. We do not want clients of mount() in
1070 * userspace to set this flag, but we must filter it out if we want
1071 * MNT_UPDATE on the root file system to work.
1072 * MNT_ROOTFS should only be set by the kernel when mounting its
1073 * root file system.
1074 */
1075 flags &= ~MNT_ROOTFS;
1076
1077 fstype = malloc(MFSNAMELEN, M_TEMP, M_WAITOK);
1078 error = copyinstr(uap->type, fstype, MFSNAMELEN, NULL);
1079 if (error) {
1080 free(fstype, M_TEMP);
1081 return (error);
1082 }
1083
1084 AUDIT_ARG_TEXT(fstype);
1085 vfsp = vfs_byname_kld(fstype, td, &error);
1086 free(fstype, M_TEMP);
1087 if (vfsp == NULL)
1088 return (EINVAL);
1089 if (((vfsp->vfc_flags & VFCF_SBDRY) != 0 &&
1090 vfsp->vfc_vfsops_sd->vfs_cmount == NULL) ||
1091 ((vfsp->vfc_flags & VFCF_SBDRY) == 0 &&
1092 vfsp->vfc_vfsops->vfs_cmount == NULL))
1093 return (EOPNOTSUPP);
1094
1095 ma = mount_argsu(ma, "fstype", uap->type, MFSNAMELEN);
1096 ma = mount_argsu(ma, "fspath", uap->path, MNAMELEN);
1097 ma = mount_argb(ma, flags & MNT_RDONLY, "noro");
1098 ma = mount_argb(ma, !(flags & MNT_NOSUID), "nosuid");
1099 ma = mount_argb(ma, !(flags & MNT_NOEXEC), "noexec");
1100
1101 if ((vfsp->vfc_flags & VFCF_SBDRY) != 0)
1102 return (vfsp->vfc_vfsops_sd->vfs_cmount(ma, uap->data, flags));
1103 return (vfsp->vfc_vfsops->vfs_cmount(ma, uap->data, flags));
1104 }
1105
1106 /*
1107 * vfs_domount_first(): first file system mount (not update)
1108 */
1109 static int
vfs_domount_first(struct thread * td,struct vfsconf * vfsp,char * fspath,struct vnode * vp,uint64_t fsflags,struct vfsoptlist ** optlist)1110 vfs_domount_first(
1111 struct thread *td, /* Calling thread. */
1112 struct vfsconf *vfsp, /* File system type. */
1113 char *fspath, /* Mount path. */
1114 struct vnode *vp, /* Vnode to be covered. */
1115 uint64_t fsflags, /* Flags common to all filesystems. */
1116 struct vfsoptlist **optlist /* Options local to the filesystem. */
1117 )
1118 {
1119 struct vattr va;
1120 struct mount *mp;
1121 struct vnode *newdp, *rootvp;
1122 int error, error1;
1123 bool unmounted;
1124
1125 ASSERT_VOP_ELOCKED(vp, __func__);
1126 KASSERT((fsflags & MNT_UPDATE) == 0, ("MNT_UPDATE shouldn't be here"));
1127
1128 /*
1129 * If the jail of the calling thread lacks permission for this type of
1130 * file system, or is trying to cover its own root, deny immediately.
1131 */
1132 if (jailed(td->td_ucred) && (!prison_allow(td->td_ucred,
1133 vfsp->vfc_prison_flag) || vp == td->td_ucred->cr_prison->pr_root)) {
1134 vput(vp);
1135 return (EPERM);
1136 }
1137
1138 /*
1139 * If the user is not root, ensure that they own the directory
1140 * onto which we are attempting to mount.
1141 */
1142 error = VOP_GETATTR(vp, &va, td->td_ucred);
1143 if (error == 0 && va.va_uid != td->td_ucred->cr_uid)
1144 error = priv_check_cred(td->td_ucred, PRIV_VFS_ADMIN);
1145 if (error == 0)
1146 error = vinvalbuf(vp, V_SAVE, 0, 0);
1147 if (vfsp->vfc_flags & VFCF_FILEMOUNT) {
1148 if (error == 0 && vp->v_type != VDIR && vp->v_type != VREG)
1149 error = EINVAL;
1150 /*
1151 * For file mounts, ensure that there is only one hardlink to the file.
1152 */
1153 if (error == 0 && vp->v_type == VREG && va.va_nlink != 1)
1154 error = EINVAL;
1155 } else {
1156 if (error == 0 && vp->v_type != VDIR)
1157 error = ENOTDIR;
1158 }
1159 if (error == 0 && (fsflags & MNT_EMPTYDIR) != 0)
1160 error = vn_dir_check_empty(vp);
1161 if (error == 0) {
1162 VI_LOCK(vp);
1163 if ((vp->v_iflag & VI_MOUNT) == 0 && vp->v_mountedhere == NULL)
1164 vp->v_iflag |= VI_MOUNT;
1165 else
1166 error = EBUSY;
1167 VI_UNLOCK(vp);
1168 }
1169 if (error != 0) {
1170 vput(vp);
1171 return (error);
1172 }
1173 vn_seqc_write_begin(vp);
1174 VOP_UNLOCK(vp);
1175
1176 /* Allocate and initialize the filesystem. */
1177 mp = vfs_mount_alloc(vp, vfsp, fspath, td->td_ucred);
1178 /* XXXMAC: pass to vfs_mount_alloc? */
1179 mp->mnt_optnew = *optlist;
1180 /* Set the mount level flags. */
1181 mp->mnt_flag = (fsflags &
1182 (MNT_UPDATEMASK | MNT_ROOTFS | MNT_RDONLY | MNT_FORCE));
1183
1184 /*
1185 * Mount the filesystem.
1186 * XXX The final recipients of VFS_MOUNT just overwrite the ndp they
1187 * get. No freeing of cn_pnbuf.
1188 */
1189 error1 = 0;
1190 unmounted = true;
1191 if ((error = VFS_MOUNT(mp)) != 0 ||
1192 (error1 = VFS_STATFS(mp, &mp->mnt_stat)) != 0 ||
1193 (error1 = VFS_ROOT(mp, LK_EXCLUSIVE, &newdp)) != 0) {
1194 rootvp = NULL;
1195 if (error1 != 0) {
1196 MPASS(error == 0);
1197 rootvp = vfs_cache_root_clear(mp);
1198 if (rootvp != NULL) {
1199 vhold(rootvp);
1200 vrele(rootvp);
1201 }
1202 (void)vn_start_write(NULL, &mp, V_WAIT);
1203 MNT_ILOCK(mp);
1204 mp->mnt_kern_flag |= MNTK_UNMOUNT | MNTK_UNMOUNTF;
1205 MNT_IUNLOCK(mp);
1206 VFS_PURGE(mp);
1207 error = VFS_UNMOUNT(mp, 0);
1208 vn_finished_write(mp);
1209 if (error != 0) {
1210 printf(
1211 "failed post-mount (%d): rollback unmount returned %d\n",
1212 error1, error);
1213 unmounted = false;
1214 }
1215 error = error1;
1216 }
1217 vfs_unbusy(mp);
1218 mp->mnt_vnodecovered = NULL;
1219 if (unmounted) {
1220 /* XXXKIB wait for mnt_lockref drain? */
1221 vfs_mount_destroy(mp);
1222 }
1223 VI_LOCK(vp);
1224 vp->v_iflag &= ~VI_MOUNT;
1225 VI_UNLOCK(vp);
1226 if (rootvp != NULL) {
1227 vn_seqc_write_end(rootvp);
1228 vdrop(rootvp);
1229 }
1230 vn_seqc_write_end(vp);
1231 vrele(vp);
1232 return (error);
1233 }
1234 vn_seqc_write_begin(newdp);
1235 VOP_UNLOCK(newdp);
1236
1237 if (mp->mnt_opt != NULL)
1238 vfs_freeopts(mp->mnt_opt);
1239 mp->mnt_opt = mp->mnt_optnew;
1240 *optlist = NULL;
1241
1242 /*
1243 * Prevent external consumers of mount options from reading mnt_optnew.
1244 */
1245 mp->mnt_optnew = NULL;
1246
1247 MNT_ILOCK(mp);
1248 if ((mp->mnt_flag & MNT_ASYNC) != 0 &&
1249 (mp->mnt_kern_flag & MNTK_NOASYNC) == 0)
1250 mp->mnt_kern_flag |= MNTK_ASYNC;
1251 else
1252 mp->mnt_kern_flag &= ~MNTK_ASYNC;
1253 MNT_IUNLOCK(mp);
1254
1255 /*
1256 * VIRF_MOUNTPOINT and v_mountedhere need to be set under the
1257 * vp lock to satisfy vfs_lookup() requirements.
1258 */
1259 VOP_LOCK(vp, LK_EXCLUSIVE | LK_RETRY);
1260 VI_LOCK(vp);
1261 vn_irflag_set_locked(vp, VIRF_MOUNTPOINT);
1262 vp->v_mountedhere = mp;
1263 VI_UNLOCK(vp);
1264 VOP_UNLOCK(vp);
1265 cache_purge(vp);
1266
1267 /*
1268 * We need to lock both vnodes.
1269 *
1270 * Use vn_lock_pair to avoid establishing an ordering between vnodes
1271 * from different filesystems.
1272 */
1273 vn_lock_pair(vp, false, LK_EXCLUSIVE, newdp, false, LK_EXCLUSIVE);
1274
1275 VI_LOCK(vp);
1276 vp->v_iflag &= ~VI_MOUNT;
1277 VI_UNLOCK(vp);
1278 /* Place the new filesystem at the end of the mount list. */
1279 mtx_lock(&mountlist_mtx);
1280 TAILQ_INSERT_TAIL(&mountlist, mp, mnt_list);
1281 mtx_unlock(&mountlist_mtx);
1282 vfs_event_signal(NULL, VQ_MOUNT, 0);
1283 VOP_UNLOCK(vp);
1284 EVENTHANDLER_DIRECT_INVOKE(vfs_mounted, mp, newdp, td);
1285 VOP_UNLOCK(newdp);
1286 mount_devctl_event("MOUNT", mp, false);
1287 mountcheckdirs(vp, newdp);
1288 vn_seqc_write_end(vp);
1289 vn_seqc_write_end(newdp);
1290 vrele(newdp);
1291 if ((mp->mnt_flag & MNT_RDONLY) == 0)
1292 vfs_allocate_syncvnode(mp);
1293 vfs_op_exit(mp);
1294 vfs_unbusy(mp);
1295 return (0);
1296 }
1297
1298 /*
1299 * vfs_domount_update(): update of mounted file system
1300 */
1301 static int
vfs_domount_update(struct thread * td,struct vnode * vp,uint64_t fsflags,bool jail_export,struct vfsoptlist ** optlist)1302 vfs_domount_update(
1303 struct thread *td, /* Calling thread. */
1304 struct vnode *vp, /* Mount point vnode. */
1305 uint64_t fsflags, /* Flags common to all filesystems. */
1306 bool jail_export, /* Got export option in vnet prison. */
1307 struct vfsoptlist **optlist /* Options local to the filesystem. */
1308 )
1309 {
1310 struct export_args export;
1311 struct o2export_args o2export;
1312 struct vnode *rootvp;
1313 void *bufp;
1314 struct mount *mp;
1315 int error, export_error, i, len, fsid_up_len;
1316 uint64_t flag, mnt_union;
1317 gid_t *grps;
1318 fsid_t *fsid_up;
1319 bool vfs_suser_failed;
1320
1321 ASSERT_VOP_ELOCKED(vp, __func__);
1322 KASSERT((fsflags & MNT_UPDATE) != 0, ("MNT_UPDATE should be here"));
1323 mp = vp->v_mount;
1324
1325 if ((vp->v_vflag & VV_ROOT) == 0) {
1326 if (vfs_copyopt(*optlist, "export", &export, sizeof(export))
1327 == 0)
1328 error = EXDEV;
1329 else
1330 error = EINVAL;
1331 vput(vp);
1332 return (error);
1333 }
1334
1335 /*
1336 * We only allow the filesystem to be reloaded if it
1337 * is currently mounted read-only.
1338 */
1339 flag = mp->mnt_flag;
1340 if ((fsflags & MNT_RELOAD) != 0 && (flag & MNT_RDONLY) == 0) {
1341 vput(vp);
1342 return (EOPNOTSUPP); /* Needs translation */
1343 }
1344 /*
1345 * Only privileged root, or (if MNT_USER is set) the user that
1346 * did the original mount is permitted to update it.
1347 */
1348 /*
1349 * For the case of mountd(8) doing exports in a jail, the vfs_suser()
1350 * call does not cause failure. vfs_domount() has already checked
1351 * that "root" is doing this and vfs_suser() will fail when
1352 * the file system has been mounted outside the jail.
1353 * jail_export set true indicates that "export" is not mixed
1354 * with other options that change mount behaviour.
1355 */
1356 vfs_suser_failed = false;
1357 error = vfs_suser(mp, td);
1358 if (jail_export && error != 0) {
1359 error = 0;
1360 vfs_suser_failed = true;
1361 }
1362 if (error != 0) {
1363 vput(vp);
1364 return (error);
1365 }
1366 if (vfs_busy(mp, MBF_NOWAIT)) {
1367 vput(vp);
1368 return (EBUSY);
1369 }
1370 VI_LOCK(vp);
1371 if ((vp->v_iflag & VI_MOUNT) != 0 || vp->v_mountedhere != NULL) {
1372 VI_UNLOCK(vp);
1373 vfs_unbusy(mp);
1374 vput(vp);
1375 return (EBUSY);
1376 }
1377 vp->v_iflag |= VI_MOUNT;
1378 VI_UNLOCK(vp);
1379 VOP_UNLOCK(vp);
1380
1381 rootvp = NULL;
1382 vfs_op_enter(mp);
1383 vn_seqc_write_begin(vp);
1384
1385 if (vfs_getopt(*optlist, "fsid", (void **)&fsid_up,
1386 &fsid_up_len) == 0) {
1387 if (fsid_up_len != sizeof(*fsid_up)) {
1388 error = EINVAL;
1389 goto end;
1390 }
1391 if (fsidcmp(fsid_up, &mp->mnt_stat.f_fsid) != 0) {
1392 error = ENOENT;
1393 goto end;
1394 }
1395 vfs_deleteopt(*optlist, "fsid");
1396 }
1397
1398 mnt_union = 0;
1399 MNT_ILOCK(mp);
1400 if ((mp->mnt_kern_flag & MNTK_UNMOUNT) != 0) {
1401 MNT_IUNLOCK(mp);
1402 error = EBUSY;
1403 goto end;
1404 }
1405 if (vfs_suser_failed) {
1406 KASSERT((fsflags & (MNT_EXPORTED | MNT_UPDATE)) ==
1407 (MNT_EXPORTED | MNT_UPDATE),
1408 ("%s: jailed export did not set expected fsflags",
1409 __func__));
1410 /*
1411 * For this case, only MNT_UPDATE and
1412 * MNT_EXPORTED have been set in fsflags
1413 * by the options. Only set MNT_UPDATE,
1414 * since that is the one that would be set
1415 * when set in fsflags, below.
1416 */
1417 mp->mnt_flag |= MNT_UPDATE;
1418 } else {
1419 mp->mnt_flag &= ~MNT_UPDATEMASK;
1420 if ((mp->mnt_flag & MNT_UNION) == 0 &&
1421 (fsflags & MNT_UNION) != 0) {
1422 fsflags &= ~MNT_UNION;
1423 mnt_union = MNT_UNION;
1424 }
1425 mp->mnt_flag |= fsflags & (MNT_RELOAD | MNT_FORCE | MNT_UPDATE |
1426 MNT_SNAPSHOT | MNT_ROOTFS | MNT_UPDATEMASK | MNT_RDONLY);
1427 if ((mp->mnt_flag & MNT_ASYNC) == 0)
1428 mp->mnt_kern_flag &= ~MNTK_ASYNC;
1429 }
1430 rootvp = vfs_cache_root_clear(mp);
1431 MNT_IUNLOCK(mp);
1432 mp->mnt_optnew = *optlist;
1433 vfs_mergeopts(mp->mnt_optnew, mp->mnt_opt);
1434
1435 /*
1436 * Mount the filesystem.
1437 * XXX The final recipients of VFS_MOUNT just overwrite the ndp they
1438 * get. No freeing of cn_pnbuf.
1439 */
1440 /*
1441 * For the case of mountd(8) doing exports from within a vnet jail,
1442 * "from" is typically not set correctly such that VFS_MOUNT() will
1443 * return ENOENT. It is not obvious that VFS_MOUNT() ever needs to be
1444 * called when mountd is doing exports, but this check only applies to
1445 * the specific case where it is running inside a vnet jail, to
1446 * avoid any POLA violation.
1447 */
1448 error = 0;
1449 if (!jail_export)
1450 error = VFS_MOUNT(mp);
1451
1452 export_error = 0;
1453 /* Process the export option. */
1454 if (error == 0 && vfs_getopt(mp->mnt_optnew, "export", &bufp,
1455 &len) == 0) {
1456 /* Assume that there is only 1 ABI for each length. */
1457 switch (len) {
1458 case (sizeof(struct oexport_args)):
1459 bzero(&o2export, sizeof(o2export));
1460 /* FALLTHROUGH */
1461 case (sizeof(o2export)):
1462 bcopy(bufp, &o2export, len);
1463 export.ex_flags = (uint64_t)o2export.ex_flags;
1464 export.ex_root = o2export.ex_root;
1465 export.ex_uid = o2export.ex_anon.cr_uid;
1466 export.ex_groups = NULL;
1467 export.ex_ngroups = o2export.ex_anon.cr_ngroups;
1468 if (export.ex_ngroups > 0) {
1469 if (export.ex_ngroups <= XU_NGROUPS) {
1470 export.ex_groups = malloc(
1471 export.ex_ngroups * sizeof(gid_t),
1472 M_TEMP, M_WAITOK);
1473 for (i = 0; i < export.ex_ngroups; i++)
1474 export.ex_groups[i] =
1475 o2export.ex_anon.cr_groups[i];
1476 } else
1477 export_error = EINVAL;
1478 } else if (export.ex_ngroups < 0)
1479 export_error = EINVAL;
1480 export.ex_addr = o2export.ex_addr;
1481 export.ex_addrlen = o2export.ex_addrlen;
1482 export.ex_mask = o2export.ex_mask;
1483 export.ex_masklen = o2export.ex_masklen;
1484 export.ex_indexfile = o2export.ex_indexfile;
1485 export.ex_numsecflavors = o2export.ex_numsecflavors;
1486 if (export.ex_numsecflavors < MAXSECFLAVORS) {
1487 for (i = 0; i < export.ex_numsecflavors; i++)
1488 export.ex_secflavors[i] =
1489 o2export.ex_secflavors[i];
1490 } else
1491 export_error = EINVAL;
1492 if (export_error == 0)
1493 export_error = vfs_export(mp, &export, true);
1494 free(export.ex_groups, M_TEMP);
1495 break;
1496 case (sizeof(export)):
1497 bcopy(bufp, &export, len);
1498 grps = NULL;
1499 if (export.ex_ngroups > 0) {
1500 if (export.ex_ngroups <= NGROUPS_MAX) {
1501 grps = malloc(export.ex_ngroups *
1502 sizeof(gid_t), M_TEMP, M_WAITOK);
1503 export_error = copyin(export.ex_groups,
1504 grps, export.ex_ngroups *
1505 sizeof(gid_t));
1506 if (export_error == 0)
1507 export.ex_groups = grps;
1508 } else
1509 export_error = EINVAL;
1510 } else if (export.ex_ngroups == 0)
1511 export.ex_groups = NULL;
1512 else
1513 export_error = EINVAL;
1514 if (export_error == 0)
1515 export_error = vfs_export(mp, &export, true);
1516 free(grps, M_TEMP);
1517 break;
1518 default:
1519 export_error = EINVAL;
1520 break;
1521 }
1522 }
1523
1524 MNT_ILOCK(mp);
1525 if (error == 0) {
1526 mp->mnt_flag &= ~(MNT_UPDATE | MNT_RELOAD | MNT_FORCE |
1527 MNT_SNAPSHOT);
1528 mp->mnt_flag |= mnt_union;
1529 } else {
1530 /*
1531 * If we fail, restore old mount flags. MNT_QUOTA is special,
1532 * because it is not part of MNT_UPDATEMASK, but it could have
1533 * changed in the meantime if quotactl(2) was called.
1534 * All in all we want current value of MNT_QUOTA, not the old
1535 * one.
1536 */
1537 mp->mnt_flag = (mp->mnt_flag & MNT_QUOTA) | (flag & ~MNT_QUOTA);
1538 }
1539 if ((mp->mnt_flag & MNT_ASYNC) != 0 &&
1540 (mp->mnt_kern_flag & MNTK_NOASYNC) == 0)
1541 mp->mnt_kern_flag |= MNTK_ASYNC;
1542 else
1543 mp->mnt_kern_flag &= ~MNTK_ASYNC;
1544 MNT_IUNLOCK(mp);
1545
1546 if (error != 0)
1547 goto end;
1548
1549 mount_devctl_event("REMOUNT", mp, true);
1550 if (mp->mnt_opt != NULL)
1551 vfs_freeopts(mp->mnt_opt);
1552 mp->mnt_opt = mp->mnt_optnew;
1553 *optlist = NULL;
1554 (void)VFS_STATFS(mp, &mp->mnt_stat);
1555 /*
1556 * Prevent external consumers of mount options from reading
1557 * mnt_optnew.
1558 */
1559 mp->mnt_optnew = NULL;
1560
1561 if ((mp->mnt_flag & MNT_RDONLY) == 0)
1562 vfs_allocate_syncvnode(mp);
1563 else
1564 vfs_deallocate_syncvnode(mp);
1565 end:
1566 vfs_op_exit(mp);
1567 if (rootvp != NULL) {
1568 vn_seqc_write_end(rootvp);
1569 vrele(rootvp);
1570 }
1571 vn_seqc_write_end(vp);
1572 vfs_unbusy(mp);
1573 VI_LOCK(vp);
1574 vp->v_iflag &= ~VI_MOUNT;
1575 VI_UNLOCK(vp);
1576 vrele(vp);
1577 return (error != 0 ? error : export_error);
1578 }
1579
1580 /*
1581 * vfs_domount(): actually attempt a filesystem mount.
1582 */
1583 static int
vfs_domount(struct thread * td,const char * fstype,char * fspath,uint64_t fsflags,bool jail_export,struct vfsoptlist ** optlist)1584 vfs_domount(
1585 struct thread *td, /* Calling thread. */
1586 const char *fstype, /* Filesystem type. */
1587 char *fspath, /* Mount path. */
1588 uint64_t fsflags, /* Flags common to all filesystems. */
1589 bool jail_export, /* Got export option in vnet prison. */
1590 struct vfsoptlist **optlist /* Options local to the filesystem. */
1591 )
1592 {
1593 struct vfsconf *vfsp;
1594 struct nameidata nd;
1595 struct vnode *vp;
1596 char *pathbuf;
1597 int error;
1598
1599 /*
1600 * Be ultra-paranoid about making sure the type and fspath
1601 * variables will fit in our mp buffers, including the
1602 * terminating NUL.
1603 */
1604 if (strlen(fstype) >= MFSNAMELEN || strlen(fspath) >= MNAMELEN)
1605 return (ENAMETOOLONG);
1606
1607 if (jail_export) {
1608 error = priv_check(td, PRIV_NFS_DAEMON);
1609 if (error)
1610 return (error);
1611 } else if (jailed(td->td_ucred) || usermount == 0) {
1612 if ((error = priv_check(td, PRIV_VFS_MOUNT)) != 0)
1613 return (error);
1614 }
1615
1616 /*
1617 * Do not allow NFS export or MNT_SUIDDIR by unprivileged users.
1618 */
1619 if (fsflags & MNT_EXPORTED) {
1620 error = priv_check(td, PRIV_VFS_MOUNT_EXPORTED);
1621 if (error)
1622 return (error);
1623 }
1624 if (fsflags & MNT_SUIDDIR) {
1625 error = priv_check(td, PRIV_VFS_MOUNT_SUIDDIR);
1626 if (error)
1627 return (error);
1628 }
1629 /*
1630 * Silently enforce MNT_NOSUID and MNT_USER for unprivileged users.
1631 */
1632 if ((fsflags & (MNT_NOSUID | MNT_USER)) != (MNT_NOSUID | MNT_USER)) {
1633 if (priv_check(td, PRIV_VFS_MOUNT_NONUSER) != 0)
1634 fsflags |= MNT_NOSUID | MNT_USER;
1635 }
1636
1637 /* Load KLDs before we lock the covered vnode to avoid reversals. */
1638 vfsp = NULL;
1639 if ((fsflags & MNT_UPDATE) == 0) {
1640 /* Don't try to load KLDs if we're mounting the root. */
1641 if (fsflags & MNT_ROOTFS) {
1642 if ((vfsp = vfs_byname(fstype)) == NULL)
1643 return (ENODEV);
1644 } else {
1645 if ((vfsp = vfs_byname_kld(fstype, td, &error)) == NULL)
1646 return (error);
1647 }
1648 }
1649
1650 /*
1651 * Get vnode to be covered or mount point's vnode in case of MNT_UPDATE.
1652 */
1653 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNODE1 | WANTPARENT,
1654 UIO_SYSSPACE, fspath);
1655 error = namei(&nd);
1656 if (error != 0)
1657 return (error);
1658 vp = nd.ni_vp;
1659 /*
1660 * Don't allow stacking file mounts to work around problems with the way
1661 * that namei sets nd.ni_dvp to vp_crossmp for these.
1662 */
1663 if (vp->v_type == VREG)
1664 fsflags |= MNT_NOCOVER;
1665 if ((fsflags & MNT_UPDATE) == 0) {
1666 if ((vp->v_vflag & VV_ROOT) != 0 &&
1667 (fsflags & MNT_NOCOVER) != 0) {
1668 vput(vp);
1669 error = EBUSY;
1670 goto out;
1671 }
1672 pathbuf = malloc(MNAMELEN, M_TEMP, M_WAITOK);
1673 strcpy(pathbuf, fspath);
1674 /*
1675 * Note: we allow any vnode type here. If the path sanity check
1676 * succeeds, the type will be validated in vfs_domount_first
1677 * above.
1678 */
1679 if (vp->v_type == VDIR)
1680 error = vn_path_to_global_path(td, vp, pathbuf,
1681 MNAMELEN);
1682 else
1683 error = vn_path_to_global_path_hardlink(td, vp,
1684 nd.ni_dvp, pathbuf, MNAMELEN,
1685 nd.ni_cnd.cn_nameptr, nd.ni_cnd.cn_namelen);
1686 if (error == 0) {
1687 error = vfs_domount_first(td, vfsp, pathbuf, vp,
1688 fsflags, optlist);
1689 }
1690 free(pathbuf, M_TEMP);
1691 } else
1692 error = vfs_domount_update(td, vp, fsflags, jail_export,
1693 optlist);
1694
1695 out:
1696 NDFREE_PNBUF(&nd);
1697 vrele(nd.ni_dvp);
1698
1699 return (error);
1700 }
1701
1702 /*
1703 * Unmount a filesystem.
1704 *
1705 * Note: unmount takes a path to the vnode mounted on as argument, not
1706 * special file (as before).
1707 */
1708 #ifndef _SYS_SYSPROTO_H_
1709 struct unmount_args {
1710 char *path;
1711 int flags;
1712 };
1713 #endif
1714 /* ARGSUSED */
1715 int
sys_unmount(struct thread * td,struct unmount_args * uap)1716 sys_unmount(struct thread *td, struct unmount_args *uap)
1717 {
1718
1719 return (kern_unmount(td, uap->path, uap->flags));
1720 }
1721
1722 int
kern_unmount(struct thread * td,const char * path,int flags)1723 kern_unmount(struct thread *td, const char *path, int flags)
1724 {
1725 struct nameidata nd;
1726 struct mount *mp;
1727 char *fsidbuf, *pathbuf;
1728 fsid_t fsid;
1729 int error;
1730
1731 AUDIT_ARG_VALUE(flags);
1732 if (jailed(td->td_ucred) || usermount == 0) {
1733 error = priv_check(td, PRIV_VFS_UNMOUNT);
1734 if (error)
1735 return (error);
1736 }
1737
1738 if (flags & MNT_BYFSID) {
1739 fsidbuf = malloc(MNAMELEN, M_TEMP, M_WAITOK);
1740 error = copyinstr(path, fsidbuf, MNAMELEN, NULL);
1741 if (error) {
1742 free(fsidbuf, M_TEMP);
1743 return (error);
1744 }
1745
1746 AUDIT_ARG_TEXT(fsidbuf);
1747 /* Decode the filesystem ID. */
1748 if (sscanf(fsidbuf, "FSID:%d:%d", &fsid.val[0], &fsid.val[1]) != 2) {
1749 free(fsidbuf, M_TEMP);
1750 return (EINVAL);
1751 }
1752
1753 mp = vfs_getvfs(&fsid);
1754 free(fsidbuf, M_TEMP);
1755 if (mp == NULL) {
1756 return (ENOENT);
1757 }
1758 } else {
1759 pathbuf = malloc(MNAMELEN, M_TEMP, M_WAITOK);
1760 error = copyinstr(path, pathbuf, MNAMELEN, NULL);
1761 if (error) {
1762 free(pathbuf, M_TEMP);
1763 return (error);
1764 }
1765
1766 /*
1767 * Try to find global path for path argument.
1768 */
1769 NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNODE1,
1770 UIO_SYSSPACE, pathbuf);
1771 if (namei(&nd) == 0) {
1772 NDFREE_PNBUF(&nd);
1773 error = vn_path_to_global_path(td, nd.ni_vp, pathbuf,
1774 MNAMELEN);
1775 if (error == 0)
1776 vput(nd.ni_vp);
1777 }
1778 mtx_lock(&mountlist_mtx);
1779 TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
1780 if (strcmp(mp->mnt_stat.f_mntonname, pathbuf) == 0) {
1781 vfs_ref(mp);
1782 break;
1783 }
1784 }
1785 mtx_unlock(&mountlist_mtx);
1786 free(pathbuf, M_TEMP);
1787 if (mp == NULL) {
1788 /*
1789 * Previously we returned ENOENT for a nonexistent path and
1790 * EINVAL for a non-mountpoint. We cannot tell these apart
1791 * now, so in the !MNT_BYFSID case return the more likely
1792 * EINVAL for compatibility.
1793 */
1794 return (EINVAL);
1795 }
1796 }
1797
1798 /*
1799 * Don't allow unmounting the root filesystem.
1800 */
1801 if (mp->mnt_flag & MNT_ROOTFS) {
1802 vfs_rel(mp);
1803 return (EINVAL);
1804 }
1805 error = dounmount(mp, flags, td);
1806 return (error);
1807 }
1808
1809 /*
1810 * Return error if any of the vnodes, ignoring the root vnode
1811 * and the syncer vnode, have non-zero usecount.
1812 *
1813 * This function is purely advisory - it can return false positives
1814 * and negatives.
1815 */
1816 static int
vfs_check_usecounts(struct mount * mp)1817 vfs_check_usecounts(struct mount *mp)
1818 {
1819 struct vnode *vp, *mvp;
1820
1821 MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
1822 if ((vp->v_vflag & VV_ROOT) == 0 && vp->v_type != VNON &&
1823 vp->v_usecount != 0) {
1824 VI_UNLOCK(vp);
1825 MNT_VNODE_FOREACH_ALL_ABORT(mp, mvp);
1826 return (EBUSY);
1827 }
1828 VI_UNLOCK(vp);
1829 }
1830
1831 return (0);
1832 }
1833
1834 static void
dounmount_cleanup(struct mount * mp,struct vnode * coveredvp,int mntkflags)1835 dounmount_cleanup(struct mount *mp, struct vnode *coveredvp, int mntkflags)
1836 {
1837
1838 mtx_assert(MNT_MTX(mp), MA_OWNED);
1839 mp->mnt_kern_flag &= ~mntkflags;
1840 if ((mp->mnt_kern_flag & MNTK_MWAIT) != 0) {
1841 mp->mnt_kern_flag &= ~MNTK_MWAIT;
1842 wakeup(mp);
1843 }
1844 vfs_op_exit_locked(mp);
1845 MNT_IUNLOCK(mp);
1846 if (coveredvp != NULL) {
1847 VOP_UNLOCK(coveredvp);
1848 vdrop(coveredvp);
1849 }
1850 vn_finished_write(mp);
1851 vfs_rel(mp);
1852 }
1853
1854 /*
1855 * There are various reference counters associated with the mount point.
1856 * Normally it is permitted to modify them without taking the mnt ilock,
1857 * but this behavior can be temporarily disabled if stable value is needed
1858 * or callers are expected to block (e.g. to not allow new users during
1859 * forced unmount).
1860 */
1861 void
vfs_op_enter(struct mount * mp)1862 vfs_op_enter(struct mount *mp)
1863 {
1864 struct mount_pcpu *mpcpu;
1865 int cpu;
1866
1867 MNT_ILOCK(mp);
1868 mp->mnt_vfs_ops++;
1869 if (mp->mnt_vfs_ops > 1) {
1870 MNT_IUNLOCK(mp);
1871 return;
1872 }
1873 vfs_op_barrier_wait(mp);
1874 CPU_FOREACH(cpu) {
1875 mpcpu = vfs_mount_pcpu_remote(mp, cpu);
1876
1877 mp->mnt_ref += mpcpu->mntp_ref;
1878 mpcpu->mntp_ref = 0;
1879
1880 mp->mnt_lockref += mpcpu->mntp_lockref;
1881 mpcpu->mntp_lockref = 0;
1882
1883 mp->mnt_writeopcount += mpcpu->mntp_writeopcount;
1884 mpcpu->mntp_writeopcount = 0;
1885 }
1886 MPASSERT(mp->mnt_ref > 0 && mp->mnt_lockref >= 0 &&
1887 mp->mnt_writeopcount >= 0, mp,
1888 ("invalid count(s): ref %d lockref %d writeopcount %d",
1889 mp->mnt_ref, mp->mnt_lockref, mp->mnt_writeopcount));
1890 MNT_IUNLOCK(mp);
1891 vfs_assert_mount_counters(mp);
1892 }
1893
1894 void
vfs_op_exit_locked(struct mount * mp)1895 vfs_op_exit_locked(struct mount *mp)
1896 {
1897
1898 mtx_assert(MNT_MTX(mp), MA_OWNED);
1899
1900 MPASSERT(mp->mnt_vfs_ops > 0, mp,
1901 ("invalid vfs_ops count %d", mp->mnt_vfs_ops));
1902 MPASSERT(mp->mnt_vfs_ops > 1 ||
1903 (mp->mnt_kern_flag & (MNTK_UNMOUNT | MNTK_SUSPEND)) == 0, mp,
1904 ("vfs_ops too low %d in unmount or suspend", mp->mnt_vfs_ops));
1905 mp->mnt_vfs_ops--;
1906 }
1907
1908 void
vfs_op_exit(struct mount * mp)1909 vfs_op_exit(struct mount *mp)
1910 {
1911
1912 MNT_ILOCK(mp);
1913 vfs_op_exit_locked(mp);
1914 MNT_IUNLOCK(mp);
1915 }
1916
1917 struct vfs_op_barrier_ipi {
1918 struct mount *mp;
1919 struct smp_rendezvous_cpus_retry_arg srcra;
1920 };
1921
1922 static void
vfs_op_action_func(void * arg)1923 vfs_op_action_func(void *arg)
1924 {
1925 struct vfs_op_barrier_ipi *vfsopipi;
1926 struct mount *mp;
1927
1928 vfsopipi = __containerof(arg, struct vfs_op_barrier_ipi, srcra);
1929 mp = vfsopipi->mp;
1930
1931 if (!vfs_op_thread_entered(mp))
1932 smp_rendezvous_cpus_done(arg);
1933 }
1934
1935 static void
vfs_op_wait_func(void * arg,int cpu)1936 vfs_op_wait_func(void *arg, int cpu)
1937 {
1938 struct vfs_op_barrier_ipi *vfsopipi;
1939 struct mount *mp;
1940 struct mount_pcpu *mpcpu;
1941
1942 vfsopipi = __containerof(arg, struct vfs_op_barrier_ipi, srcra);
1943 mp = vfsopipi->mp;
1944
1945 mpcpu = vfs_mount_pcpu_remote(mp, cpu);
1946 while (atomic_load_int(&mpcpu->mntp_thread_in_ops))
1947 cpu_spinwait();
1948 }
1949
1950 void
vfs_op_barrier_wait(struct mount * mp)1951 vfs_op_barrier_wait(struct mount *mp)
1952 {
1953 struct vfs_op_barrier_ipi vfsopipi;
1954
1955 vfsopipi.mp = mp;
1956
1957 smp_rendezvous_cpus_retry(all_cpus,
1958 smp_no_rendezvous_barrier,
1959 vfs_op_action_func,
1960 smp_no_rendezvous_barrier,
1961 vfs_op_wait_func,
1962 &vfsopipi.srcra);
1963 }
1964
1965 #ifdef DIAGNOSTIC
1966 void
vfs_assert_mount_counters(struct mount * mp)1967 vfs_assert_mount_counters(struct mount *mp)
1968 {
1969 struct mount_pcpu *mpcpu;
1970 int cpu;
1971
1972 if (mp->mnt_vfs_ops == 0)
1973 return;
1974
1975 CPU_FOREACH(cpu) {
1976 mpcpu = vfs_mount_pcpu_remote(mp, cpu);
1977 if (mpcpu->mntp_ref != 0 ||
1978 mpcpu->mntp_lockref != 0 ||
1979 mpcpu->mntp_writeopcount != 0)
1980 vfs_dump_mount_counters(mp);
1981 }
1982 }
1983
1984 void
vfs_dump_mount_counters(struct mount * mp)1985 vfs_dump_mount_counters(struct mount *mp)
1986 {
1987 struct mount_pcpu *mpcpu;
1988 int ref, lockref, writeopcount;
1989 int cpu;
1990
1991 printf("%s: mp %p vfs_ops %d\n", __func__, mp, mp->mnt_vfs_ops);
1992
1993 printf(" ref : ");
1994 ref = mp->mnt_ref;
1995 CPU_FOREACH(cpu) {
1996 mpcpu = vfs_mount_pcpu_remote(mp, cpu);
1997 printf("%d ", mpcpu->mntp_ref);
1998 ref += mpcpu->mntp_ref;
1999 }
2000 printf("\n");
2001 printf(" lockref : ");
2002 lockref = mp->mnt_lockref;
2003 CPU_FOREACH(cpu) {
2004 mpcpu = vfs_mount_pcpu_remote(mp, cpu);
2005 printf("%d ", mpcpu->mntp_lockref);
2006 lockref += mpcpu->mntp_lockref;
2007 }
2008 printf("\n");
2009 printf("writeopcount: ");
2010 writeopcount = mp->mnt_writeopcount;
2011 CPU_FOREACH(cpu) {
2012 mpcpu = vfs_mount_pcpu_remote(mp, cpu);
2013 printf("%d ", mpcpu->mntp_writeopcount);
2014 writeopcount += mpcpu->mntp_writeopcount;
2015 }
2016 printf("\n");
2017
2018 printf("counter struct total\n");
2019 printf("ref %-5d %-5d\n", mp->mnt_ref, ref);
2020 printf("lockref %-5d %-5d\n", mp->mnt_lockref, lockref);
2021 printf("writeopcount %-5d %-5d\n", mp->mnt_writeopcount, writeopcount);
2022
2023 panic("invalid counts on struct mount");
2024 }
2025 #endif
2026
2027 int
vfs_mount_fetch_counter(struct mount * mp,enum mount_counter which)2028 vfs_mount_fetch_counter(struct mount *mp, enum mount_counter which)
2029 {
2030 struct mount_pcpu *mpcpu;
2031 int cpu, sum;
2032
2033 switch (which) {
2034 case MNT_COUNT_REF:
2035 sum = mp->mnt_ref;
2036 break;
2037 case MNT_COUNT_LOCKREF:
2038 sum = mp->mnt_lockref;
2039 break;
2040 case MNT_COUNT_WRITEOPCOUNT:
2041 sum = mp->mnt_writeopcount;
2042 break;
2043 }
2044
2045 CPU_FOREACH(cpu) {
2046 mpcpu = vfs_mount_pcpu_remote(mp, cpu);
2047 switch (which) {
2048 case MNT_COUNT_REF:
2049 sum += mpcpu->mntp_ref;
2050 break;
2051 case MNT_COUNT_LOCKREF:
2052 sum += mpcpu->mntp_lockref;
2053 break;
2054 case MNT_COUNT_WRITEOPCOUNT:
2055 sum += mpcpu->mntp_writeopcount;
2056 break;
2057 }
2058 }
2059 return (sum);
2060 }
2061
2062 static bool
deferred_unmount_enqueue(struct mount * mp,uint64_t flags,bool requeue,int timeout_ticks)2063 deferred_unmount_enqueue(struct mount *mp, uint64_t flags, bool requeue,
2064 int timeout_ticks)
2065 {
2066 bool enqueued;
2067
2068 enqueued = false;
2069 mtx_lock(&deferred_unmount_lock);
2070 if ((mp->mnt_taskqueue_flags & MNT_DEFERRED) == 0 || requeue) {
2071 mp->mnt_taskqueue_flags = flags | MNT_DEFERRED;
2072 STAILQ_INSERT_TAIL(&deferred_unmount_list, mp,
2073 mnt_taskqueue_link);
2074 enqueued = true;
2075 }
2076 mtx_unlock(&deferred_unmount_lock);
2077
2078 if (enqueued) {
2079 taskqueue_enqueue_timeout(taskqueue_deferred_unmount,
2080 &deferred_unmount_task, timeout_ticks);
2081 }
2082
2083 return (enqueued);
2084 }
2085
2086 /*
2087 * Taskqueue handler for processing async/recursive unmounts
2088 */
2089 static void
vfs_deferred_unmount(void * argi __unused,int pending __unused)2090 vfs_deferred_unmount(void *argi __unused, int pending __unused)
2091 {
2092 STAILQ_HEAD(, mount) local_unmounts;
2093 uint64_t flags;
2094 struct mount *mp, *tmp;
2095 int error;
2096 unsigned int retries;
2097 bool unmounted;
2098
2099 STAILQ_INIT(&local_unmounts);
2100 mtx_lock(&deferred_unmount_lock);
2101 STAILQ_CONCAT(&local_unmounts, &deferred_unmount_list);
2102 mtx_unlock(&deferred_unmount_lock);
2103
2104 STAILQ_FOREACH_SAFE(mp, &local_unmounts, mnt_taskqueue_link, tmp) {
2105 flags = mp->mnt_taskqueue_flags;
2106 KASSERT((flags & MNT_DEFERRED) != 0,
2107 ("taskqueue unmount without MNT_DEFERRED"));
2108 error = dounmount(mp, flags, curthread);
2109 if (error != 0) {
2110 MNT_ILOCK(mp);
2111 unmounted = ((mp->mnt_kern_flag & MNTK_REFEXPIRE) != 0);
2112 MNT_IUNLOCK(mp);
2113
2114 /*
2115 * The deferred unmount thread is the only thread that
2116 * modifies the retry counts, so locking/atomics aren't
2117 * needed here.
2118 */
2119 retries = (mp->mnt_unmount_retries)++;
2120 deferred_unmount_total_retries++;
2121 if (!unmounted && retries < deferred_unmount_retry_limit) {
2122 deferred_unmount_enqueue(mp, flags, true,
2123 -deferred_unmount_retry_delay_hz);
2124 } else {
2125 if (retries >= deferred_unmount_retry_limit) {
2126 printf("giving up on deferred unmount "
2127 "of %s after %d retries, error %d\n",
2128 mp->mnt_stat.f_mntonname, retries, error);
2129 }
2130 vfs_rel(mp);
2131 }
2132 }
2133 }
2134 }
2135
2136 /*
2137 * Do the actual filesystem unmount.
2138 */
2139 int
dounmount(struct mount * mp,uint64_t flags,struct thread * td)2140 dounmount(struct mount *mp, uint64_t flags, struct thread *td)
2141 {
2142 struct mount_upper_node *upper;
2143 struct vnode *coveredvp, *rootvp;
2144 int error;
2145 uint64_t async_flag;
2146 int mnt_gen_r;
2147 unsigned int retries;
2148
2149 KASSERT((flags & MNT_DEFERRED) == 0 ||
2150 (flags & (MNT_RECURSE | MNT_FORCE)) == (MNT_RECURSE | MNT_FORCE),
2151 ("MNT_DEFERRED requires MNT_RECURSE | MNT_FORCE"));
2152
2153 /*
2154 * If the caller has explicitly requested the unmount to be handled by
2155 * the taskqueue and we're not already in taskqueue context, queue
2156 * up the unmount request and exit. This is done prior to any
2157 * credential checks; MNT_DEFERRED should be used only for kernel-
2158 * initiated unmounts and will therefore be processed with the
2159 * (kernel) credentials of the taskqueue thread. Still, callers
2160 * should be sure this is the behavior they want.
2161 */
2162 if ((flags & MNT_DEFERRED) != 0 &&
2163 taskqueue_member(taskqueue_deferred_unmount, curthread) == 0) {
2164 if (!deferred_unmount_enqueue(mp, flags, false, 0))
2165 vfs_rel(mp);
2166 return (EINPROGRESS);
2167 }
2168
2169 /*
2170 * Only privileged root, or (if MNT_USER is set) the user that did the
2171 * original mount is permitted to unmount this filesystem.
2172 * This check should be made prior to queueing up any recursive
2173 * unmounts of upper filesystems. Those unmounts will be executed
2174 * with kernel thread credentials and are expected to succeed, so
2175 * we must at least ensure the originating context has sufficient
2176 * privilege to unmount the base filesystem before proceeding with
2177 * the uppers.
2178 */
2179 error = vfs_suser(mp, td);
2180 if (error != 0) {
2181 KASSERT((flags & MNT_DEFERRED) == 0,
2182 ("taskqueue unmount with insufficient privilege"));
2183 vfs_rel(mp);
2184 return (error);
2185 }
2186
2187 if (recursive_forced_unmount && ((flags & MNT_FORCE) != 0))
2188 flags |= MNT_RECURSE;
2189
2190 if ((flags & MNT_RECURSE) != 0) {
2191 KASSERT((flags & MNT_FORCE) != 0,
2192 ("MNT_RECURSE requires MNT_FORCE"));
2193
2194 MNT_ILOCK(mp);
2195 /*
2196 * Set MNTK_RECURSE to prevent new upper mounts from being
2197 * added, and note that an operation on the uppers list is in
2198 * progress. This will ensure that unregistration from the
2199 * uppers list, and therefore any pending unmount of the upper
2200 * FS, can't complete until after we finish walking the list.
2201 */
2202 mp->mnt_kern_flag |= MNTK_RECURSE;
2203 mp->mnt_upper_pending++;
2204 TAILQ_FOREACH(upper, &mp->mnt_uppers, mnt_upper_link) {
2205 retries = upper->mp->mnt_unmount_retries;
2206 if (retries > deferred_unmount_retry_limit) {
2207 error = EBUSY;
2208 continue;
2209 }
2210 MNT_IUNLOCK(mp);
2211
2212 vfs_ref(upper->mp);
2213 if (!deferred_unmount_enqueue(upper->mp, flags,
2214 false, 0))
2215 vfs_rel(upper->mp);
2216 MNT_ILOCK(mp);
2217 }
2218 mp->mnt_upper_pending--;
2219 if ((mp->mnt_kern_flag & MNTK_UPPER_WAITER) != 0 &&
2220 mp->mnt_upper_pending == 0) {
2221 mp->mnt_kern_flag &= ~MNTK_UPPER_WAITER;
2222 wakeup(&mp->mnt_uppers);
2223 }
2224
2225 /*
2226 * If we're not on the taskqueue, wait until the uppers list
2227 * is drained before proceeding with unmount. Otherwise, if
2228 * we are on the taskqueue and there are still pending uppers,
2229 * just re-enqueue on the end of the taskqueue.
2230 */
2231 if ((flags & MNT_DEFERRED) == 0) {
2232 while (error == 0 && !TAILQ_EMPTY(&mp->mnt_uppers)) {
2233 mp->mnt_kern_flag |= MNTK_TASKQUEUE_WAITER;
2234 error = msleep(&mp->mnt_taskqueue_link,
2235 MNT_MTX(mp), PCATCH, "umntqw", 0);
2236 }
2237 if (error != 0) {
2238 MNT_REL(mp);
2239 MNT_IUNLOCK(mp);
2240 return (error);
2241 }
2242 } else if (!TAILQ_EMPTY(&mp->mnt_uppers)) {
2243 MNT_IUNLOCK(mp);
2244 if (error == 0)
2245 deferred_unmount_enqueue(mp, flags, true, 0);
2246 return (error);
2247 }
2248 MNT_IUNLOCK(mp);
2249 KASSERT(TAILQ_EMPTY(&mp->mnt_uppers), ("mnt_uppers not empty"));
2250 }
2251
2252 /* Allow the taskqueue to safely re-enqueue on failure */
2253 if ((flags & MNT_DEFERRED) != 0)
2254 vfs_ref(mp);
2255
2256 if ((coveredvp = mp->mnt_vnodecovered) != NULL) {
2257 mnt_gen_r = mp->mnt_gen;
2258 VI_LOCK(coveredvp);
2259 vholdl(coveredvp);
2260 vn_lock(coveredvp, LK_EXCLUSIVE | LK_INTERLOCK | LK_RETRY);
2261 /*
2262 * Check for mp being unmounted while waiting for the
2263 * covered vnode lock.
2264 */
2265 if (coveredvp->v_mountedhere != mp ||
2266 coveredvp->v_mountedhere->mnt_gen != mnt_gen_r) {
2267 VOP_UNLOCK(coveredvp);
2268 vdrop(coveredvp);
2269 vfs_rel(mp);
2270 return (EBUSY);
2271 }
2272 }
2273
2274 vfs_op_enter(mp);
2275
2276 vn_start_write(NULL, &mp, V_WAIT);
2277 MNT_ILOCK(mp);
2278 if ((mp->mnt_kern_flag & MNTK_UNMOUNT) != 0 ||
2279 (mp->mnt_flag & MNT_UPDATE) != 0 ||
2280 !TAILQ_EMPTY(&mp->mnt_uppers)) {
2281 dounmount_cleanup(mp, coveredvp, 0);
2282 return (EBUSY);
2283 }
2284 mp->mnt_kern_flag |= MNTK_UNMOUNT;
2285 rootvp = vfs_cache_root_clear(mp);
2286 if (coveredvp != NULL)
2287 vn_seqc_write_begin(coveredvp);
2288 if (flags & MNT_NONBUSY) {
2289 MNT_IUNLOCK(mp);
2290 error = vfs_check_usecounts(mp);
2291 MNT_ILOCK(mp);
2292 if (error != 0) {
2293 vn_seqc_write_end(coveredvp);
2294 dounmount_cleanup(mp, coveredvp, MNTK_UNMOUNT);
2295 if (rootvp != NULL) {
2296 vn_seqc_write_end(rootvp);
2297 vrele(rootvp);
2298 }
2299 return (error);
2300 }
2301 }
2302 /* Allow filesystems to detect that a forced unmount is in progress. */
2303 if (flags & MNT_FORCE) {
2304 mp->mnt_kern_flag |= MNTK_UNMOUNTF;
2305 MNT_IUNLOCK(mp);
2306 /*
2307 * Must be done after setting MNTK_UNMOUNTF and before
2308 * waiting for mnt_lockref to become 0.
2309 */
2310 VFS_PURGE(mp);
2311 MNT_ILOCK(mp);
2312 }
2313 error = 0;
2314 if (mp->mnt_lockref) {
2315 mp->mnt_kern_flag |= MNTK_DRAINING;
2316 error = msleep(&mp->mnt_lockref, MNT_MTX(mp), PVFS,
2317 "mount drain", 0);
2318 }
2319 MNT_IUNLOCK(mp);
2320 KASSERT(mp->mnt_lockref == 0,
2321 ("%s: invalid lock refcount in the drain path @ %s:%d",
2322 __func__, __FILE__, __LINE__));
2323 KASSERT(error == 0,
2324 ("%s: invalid return value for msleep in the drain path @ %s:%d",
2325 __func__, __FILE__, __LINE__));
2326
2327 /*
2328 * We want to keep the vnode around so that we can vn_seqc_write_end
2329 * after we are done with unmount. Downgrade our reference to a mere
2330 * hold count so that we don't interefere with anything.
2331 */
2332 if (rootvp != NULL) {
2333 vhold(rootvp);
2334 vrele(rootvp);
2335 }
2336
2337 if (mp->mnt_flag & MNT_EXPUBLIC)
2338 vfs_setpublicfs(NULL, NULL, NULL);
2339
2340 vfs_periodic(mp, MNT_WAIT);
2341 MNT_ILOCK(mp);
2342 async_flag = mp->mnt_flag & MNT_ASYNC;
2343 mp->mnt_flag &= ~MNT_ASYNC;
2344 mp->mnt_kern_flag &= ~MNTK_ASYNC;
2345 MNT_IUNLOCK(mp);
2346 vfs_deallocate_syncvnode(mp);
2347 error = VFS_UNMOUNT(mp, flags);
2348 vn_finished_write(mp);
2349 vfs_rel(mp);
2350 /*
2351 * If we failed to flush the dirty blocks for this mount point,
2352 * undo all the cdir/rdir and rootvnode changes we made above.
2353 * Unless we failed to do so because the device is reporting that
2354 * it doesn't exist anymore.
2355 */
2356 if (error && error != ENXIO) {
2357 MNT_ILOCK(mp);
2358 if ((mp->mnt_flag & MNT_RDONLY) == 0) {
2359 MNT_IUNLOCK(mp);
2360 vfs_allocate_syncvnode(mp);
2361 MNT_ILOCK(mp);
2362 }
2363 mp->mnt_kern_flag &= ~(MNTK_UNMOUNT | MNTK_UNMOUNTF);
2364 mp->mnt_flag |= async_flag;
2365 if ((mp->mnt_flag & MNT_ASYNC) != 0 &&
2366 (mp->mnt_kern_flag & MNTK_NOASYNC) == 0)
2367 mp->mnt_kern_flag |= MNTK_ASYNC;
2368 if (mp->mnt_kern_flag & MNTK_MWAIT) {
2369 mp->mnt_kern_flag &= ~MNTK_MWAIT;
2370 wakeup(mp);
2371 }
2372 vfs_op_exit_locked(mp);
2373 MNT_IUNLOCK(mp);
2374 if (coveredvp) {
2375 vn_seqc_write_end(coveredvp);
2376 VOP_UNLOCK(coveredvp);
2377 vdrop(coveredvp);
2378 }
2379 if (rootvp != NULL) {
2380 vn_seqc_write_end(rootvp);
2381 vdrop(rootvp);
2382 }
2383 return (error);
2384 }
2385
2386 mtx_lock(&mountlist_mtx);
2387 TAILQ_REMOVE(&mountlist, mp, mnt_list);
2388 mtx_unlock(&mountlist_mtx);
2389 EVENTHANDLER_DIRECT_INVOKE(vfs_unmounted, mp, td);
2390 if (coveredvp != NULL) {
2391 VI_LOCK(coveredvp);
2392 vn_irflag_unset_locked(coveredvp, VIRF_MOUNTPOINT);
2393 coveredvp->v_mountedhere = NULL;
2394 vn_seqc_write_end_locked(coveredvp);
2395 VI_UNLOCK(coveredvp);
2396 VOP_UNLOCK(coveredvp);
2397 vdrop(coveredvp);
2398 }
2399 mount_devctl_event("UNMOUNT", mp, false);
2400 if (rootvp != NULL) {
2401 vn_seqc_write_end(rootvp);
2402 vdrop(rootvp);
2403 }
2404 vfs_event_signal(NULL, VQ_UNMOUNT, 0);
2405 if (rootvnode != NULL && mp == rootvnode->v_mount) {
2406 vrele(rootvnode);
2407 rootvnode = NULL;
2408 }
2409 if (mp == rootdevmp)
2410 rootdevmp = NULL;
2411 if ((flags & MNT_DEFERRED) != 0)
2412 vfs_rel(mp);
2413 vfs_mount_destroy(mp);
2414 return (0);
2415 }
2416
2417 /*
2418 * Report errors during filesystem mounting.
2419 */
2420 void
vfs_mount_error(struct mount * mp,const char * fmt,...)2421 vfs_mount_error(struct mount *mp, const char *fmt, ...)
2422 {
2423 struct vfsoptlist *moptlist = mp->mnt_optnew;
2424 va_list ap;
2425 int error, len;
2426 char *errmsg;
2427
2428 error = vfs_getopt(moptlist, "errmsg", (void **)&errmsg, &len);
2429 if (error || errmsg == NULL || len <= 0)
2430 return;
2431
2432 va_start(ap, fmt);
2433 vsnprintf(errmsg, (size_t)len, fmt, ap);
2434 va_end(ap);
2435 }
2436
2437 void
vfs_opterror(struct vfsoptlist * opts,const char * fmt,...)2438 vfs_opterror(struct vfsoptlist *opts, const char *fmt, ...)
2439 {
2440 va_list ap;
2441 int error, len;
2442 char *errmsg;
2443
2444 error = vfs_getopt(opts, "errmsg", (void **)&errmsg, &len);
2445 if (error || errmsg == NULL || len <= 0)
2446 return;
2447
2448 va_start(ap, fmt);
2449 vsnprintf(errmsg, (size_t)len, fmt, ap);
2450 va_end(ap);
2451 }
2452
2453 /*
2454 * ---------------------------------------------------------------------
2455 * Functions for querying mount options/arguments from filesystems.
2456 */
2457
2458 /*
2459 * Check that no unknown options are given
2460 */
2461 int
vfs_filteropt(struct vfsoptlist * opts,const char ** legal)2462 vfs_filteropt(struct vfsoptlist *opts, const char **legal)
2463 {
2464 struct vfsopt *opt;
2465 char errmsg[255];
2466 const char **t, *p, *q;
2467 int ret = 0;
2468
2469 TAILQ_FOREACH(opt, opts, link) {
2470 p = opt->name;
2471 q = NULL;
2472 if (p[0] == 'n' && p[1] == 'o')
2473 q = p + 2;
2474 for(t = global_opts; *t != NULL; t++) {
2475 if (strcmp(*t, p) == 0)
2476 break;
2477 if (q != NULL) {
2478 if (strcmp(*t, q) == 0)
2479 break;
2480 }
2481 }
2482 if (*t != NULL)
2483 continue;
2484 for(t = legal; *t != NULL; t++) {
2485 if (strcmp(*t, p) == 0)
2486 break;
2487 if (q != NULL) {
2488 if (strcmp(*t, q) == 0)
2489 break;
2490 }
2491 }
2492 if (*t != NULL)
2493 continue;
2494 snprintf(errmsg, sizeof(errmsg),
2495 "mount option <%s> is unknown", p);
2496 ret = EINVAL;
2497 }
2498 if (ret != 0) {
2499 TAILQ_FOREACH(opt, opts, link) {
2500 if (strcmp(opt->name, "errmsg") == 0) {
2501 strncpy((char *)opt->value, errmsg, opt->len);
2502 break;
2503 }
2504 }
2505 if (opt == NULL)
2506 printf("%s\n", errmsg);
2507 }
2508 return (ret);
2509 }
2510
2511 /*
2512 * Get a mount option by its name.
2513 *
2514 * Return 0 if the option was found, ENOENT otherwise.
2515 * If len is non-NULL it will be filled with the length
2516 * of the option. If buf is non-NULL, it will be filled
2517 * with the address of the option.
2518 */
2519 int
vfs_getopt(struct vfsoptlist * opts,const char * name,void ** buf,int * len)2520 vfs_getopt(struct vfsoptlist *opts, const char *name, void **buf, int *len)
2521 {
2522 struct vfsopt *opt;
2523
2524 KASSERT(opts != NULL, ("vfs_getopt: caller passed 'opts' as NULL"));
2525
2526 TAILQ_FOREACH(opt, opts, link) {
2527 if (strcmp(name, opt->name) == 0) {
2528 opt->seen = 1;
2529 if (len != NULL)
2530 *len = opt->len;
2531 if (buf != NULL)
2532 *buf = opt->value;
2533 return (0);
2534 }
2535 }
2536 return (ENOENT);
2537 }
2538
2539 int
vfs_getopt_pos(struct vfsoptlist * opts,const char * name)2540 vfs_getopt_pos(struct vfsoptlist *opts, const char *name)
2541 {
2542 struct vfsopt *opt;
2543
2544 if (opts == NULL)
2545 return (-1);
2546
2547 TAILQ_FOREACH(opt, opts, link) {
2548 if (strcmp(name, opt->name) == 0) {
2549 opt->seen = 1;
2550 return (opt->pos);
2551 }
2552 }
2553 return (-1);
2554 }
2555
2556 int
vfs_getopt_size(struct vfsoptlist * opts,const char * name,off_t * value)2557 vfs_getopt_size(struct vfsoptlist *opts, const char *name, off_t *value)
2558 {
2559 char *opt_value, *vtp;
2560 quad_t iv;
2561 int error, opt_len;
2562
2563 error = vfs_getopt(opts, name, (void **)&opt_value, &opt_len);
2564 if (error != 0)
2565 return (error);
2566 if (opt_len == 0 || opt_value == NULL)
2567 return (EINVAL);
2568 if (opt_value[0] == '\0' || opt_value[opt_len - 1] != '\0')
2569 return (EINVAL);
2570 iv = strtoq(opt_value, &vtp, 0);
2571 if (vtp == opt_value || (vtp[0] != '\0' && vtp[1] != '\0'))
2572 return (EINVAL);
2573 if (iv < 0)
2574 return (EINVAL);
2575 switch (vtp[0]) {
2576 case 't': case 'T':
2577 iv *= 1024;
2578 /* FALLTHROUGH */
2579 case 'g': case 'G':
2580 iv *= 1024;
2581 /* FALLTHROUGH */
2582 case 'm': case 'M':
2583 iv *= 1024;
2584 /* FALLTHROUGH */
2585 case 'k': case 'K':
2586 iv *= 1024;
2587 case '\0':
2588 break;
2589 default:
2590 return (EINVAL);
2591 }
2592 *value = iv;
2593
2594 return (0);
2595 }
2596
2597 char *
vfs_getopts(struct vfsoptlist * opts,const char * name,int * error)2598 vfs_getopts(struct vfsoptlist *opts, const char *name, int *error)
2599 {
2600 struct vfsopt *opt;
2601
2602 *error = 0;
2603 TAILQ_FOREACH(opt, opts, link) {
2604 if (strcmp(name, opt->name) != 0)
2605 continue;
2606 opt->seen = 1;
2607 if (opt->len == 0 ||
2608 ((char *)opt->value)[opt->len - 1] != '\0') {
2609 *error = EINVAL;
2610 return (NULL);
2611 }
2612 return (opt->value);
2613 }
2614 *error = ENOENT;
2615 return (NULL);
2616 }
2617
2618 int
vfs_flagopt(struct vfsoptlist * opts,const char * name,uint64_t * w,uint64_t val)2619 vfs_flagopt(struct vfsoptlist *opts, const char *name, uint64_t *w,
2620 uint64_t val)
2621 {
2622 struct vfsopt *opt;
2623
2624 TAILQ_FOREACH(opt, opts, link) {
2625 if (strcmp(name, opt->name) == 0) {
2626 opt->seen = 1;
2627 if (w != NULL)
2628 *w |= val;
2629 return (1);
2630 }
2631 }
2632 if (w != NULL)
2633 *w &= ~val;
2634 return (0);
2635 }
2636
2637 int
vfs_scanopt(struct vfsoptlist * opts,const char * name,const char * fmt,...)2638 vfs_scanopt(struct vfsoptlist *opts, const char *name, const char *fmt, ...)
2639 {
2640 va_list ap;
2641 struct vfsopt *opt;
2642 int ret;
2643
2644 KASSERT(opts != NULL, ("vfs_getopt: caller passed 'opts' as NULL"));
2645
2646 TAILQ_FOREACH(opt, opts, link) {
2647 if (strcmp(name, opt->name) != 0)
2648 continue;
2649 opt->seen = 1;
2650 if (opt->len == 0 || opt->value == NULL)
2651 return (0);
2652 if (((char *)opt->value)[opt->len - 1] != '\0')
2653 return (0);
2654 va_start(ap, fmt);
2655 ret = vsscanf(opt->value, fmt, ap);
2656 va_end(ap);
2657 return (ret);
2658 }
2659 return (0);
2660 }
2661
2662 int
vfs_setopt(struct vfsoptlist * opts,const char * name,void * value,int len)2663 vfs_setopt(struct vfsoptlist *opts, const char *name, void *value, int len)
2664 {
2665 struct vfsopt *opt;
2666
2667 TAILQ_FOREACH(opt, opts, link) {
2668 if (strcmp(name, opt->name) != 0)
2669 continue;
2670 opt->seen = 1;
2671 if (opt->value == NULL)
2672 opt->len = len;
2673 else {
2674 if (opt->len != len)
2675 return (EINVAL);
2676 bcopy(value, opt->value, len);
2677 }
2678 return (0);
2679 }
2680 return (ENOENT);
2681 }
2682
2683 int
vfs_setopt_part(struct vfsoptlist * opts,const char * name,void * value,int len)2684 vfs_setopt_part(struct vfsoptlist *opts, const char *name, void *value, int len)
2685 {
2686 struct vfsopt *opt;
2687
2688 TAILQ_FOREACH(opt, opts, link) {
2689 if (strcmp(name, opt->name) != 0)
2690 continue;
2691 opt->seen = 1;
2692 if (opt->value == NULL)
2693 opt->len = len;
2694 else {
2695 if (opt->len < len)
2696 return (EINVAL);
2697 opt->len = len;
2698 bcopy(value, opt->value, len);
2699 }
2700 return (0);
2701 }
2702 return (ENOENT);
2703 }
2704
2705 int
vfs_setopts(struct vfsoptlist * opts,const char * name,const char * value)2706 vfs_setopts(struct vfsoptlist *opts, const char *name, const char *value)
2707 {
2708 struct vfsopt *opt;
2709
2710 TAILQ_FOREACH(opt, opts, link) {
2711 if (strcmp(name, opt->name) != 0)
2712 continue;
2713 opt->seen = 1;
2714 if (opt->value == NULL)
2715 opt->len = strlen(value) + 1;
2716 else if (strlcpy(opt->value, value, opt->len) >= opt->len)
2717 return (EINVAL);
2718 return (0);
2719 }
2720 return (ENOENT);
2721 }
2722
2723 /*
2724 * Find and copy a mount option.
2725 *
2726 * The size of the buffer has to be specified
2727 * in len, if it is not the same length as the
2728 * mount option, EINVAL is returned.
2729 * Returns ENOENT if the option is not found.
2730 */
2731 int
vfs_copyopt(struct vfsoptlist * opts,const char * name,void * dest,int len)2732 vfs_copyopt(struct vfsoptlist *opts, const char *name, void *dest, int len)
2733 {
2734 struct vfsopt *opt;
2735
2736 KASSERT(opts != NULL, ("vfs_copyopt: caller passed 'opts' as NULL"));
2737
2738 TAILQ_FOREACH(opt, opts, link) {
2739 if (strcmp(name, opt->name) == 0) {
2740 opt->seen = 1;
2741 if (len != opt->len)
2742 return (EINVAL);
2743 bcopy(opt->value, dest, opt->len);
2744 return (0);
2745 }
2746 }
2747 return (ENOENT);
2748 }
2749
2750 int
__vfs_statfs(struct mount * mp,struct statfs * sbp)2751 __vfs_statfs(struct mount *mp, struct statfs *sbp)
2752 {
2753 /*
2754 * Filesystems only fill in part of the structure for updates, we
2755 * have to read the entirety first to get all content.
2756 */
2757 if (sbp != &mp->mnt_stat)
2758 memcpy(sbp, &mp->mnt_stat, sizeof(*sbp));
2759
2760 /*
2761 * Set these in case the underlying filesystem fails to do so.
2762 */
2763 sbp->f_version = STATFS_VERSION;
2764 sbp->f_namemax = NAME_MAX;
2765 sbp->f_flags = mp->mnt_flag & MNT_VISFLAGMASK;
2766 sbp->f_nvnodelistsize = mp->mnt_nvnodelistsize;
2767
2768 return (mp->mnt_op->vfs_statfs(mp, sbp));
2769 }
2770
2771 void
vfs_mountedfrom(struct mount * mp,const char * from)2772 vfs_mountedfrom(struct mount *mp, const char *from)
2773 {
2774
2775 bzero(mp->mnt_stat.f_mntfromname, sizeof mp->mnt_stat.f_mntfromname);
2776 strlcpy(mp->mnt_stat.f_mntfromname, from,
2777 sizeof mp->mnt_stat.f_mntfromname);
2778 }
2779
2780 /*
2781 * ---------------------------------------------------------------------
2782 * This is the api for building mount args and mounting filesystems from
2783 * inside the kernel.
2784 *
2785 * The API works by accumulation of individual args. First error is
2786 * latched.
2787 *
2788 * XXX: should be documented in new manpage kernel_mount(9)
2789 */
2790
2791 /* A memory allocation which must be freed when we are done */
2792 struct mntaarg {
2793 SLIST_ENTRY(mntaarg) next;
2794 };
2795
2796 /* The header for the mount arguments */
2797 struct mntarg {
2798 struct iovec *v;
2799 int len;
2800 int error;
2801 SLIST_HEAD(, mntaarg) list;
2802 };
2803
2804 /*
2805 * Add a boolean argument.
2806 *
2807 * flag is the boolean value.
2808 * name must start with "no".
2809 */
2810 struct mntarg *
mount_argb(struct mntarg * ma,int flag,const char * name)2811 mount_argb(struct mntarg *ma, int flag, const char *name)
2812 {
2813
2814 KASSERT(name[0] == 'n' && name[1] == 'o',
2815 ("mount_argb(...,%s): name must start with 'no'", name));
2816
2817 return (mount_arg(ma, name + (flag ? 2 : 0), NULL, 0));
2818 }
2819
2820 /*
2821 * Add an argument printf style
2822 */
2823 struct mntarg *
mount_argf(struct mntarg * ma,const char * name,const char * fmt,...)2824 mount_argf(struct mntarg *ma, const char *name, const char *fmt, ...)
2825 {
2826 va_list ap;
2827 struct mntaarg *maa;
2828 struct sbuf *sb;
2829 int len;
2830
2831 if (ma == NULL) {
2832 ma = malloc(sizeof *ma, M_MOUNT, M_WAITOK | M_ZERO);
2833 SLIST_INIT(&ma->list);
2834 }
2835 if (ma->error)
2836 return (ma);
2837
2838 ma->v = realloc(ma->v, sizeof *ma->v * (ma->len + 2),
2839 M_MOUNT, M_WAITOK);
2840 ma->v[ma->len].iov_base = (void *)(uintptr_t)name;
2841 ma->v[ma->len].iov_len = strlen(name) + 1;
2842 ma->len++;
2843
2844 sb = sbuf_new_auto();
2845 va_start(ap, fmt);
2846 sbuf_vprintf(sb, fmt, ap);
2847 va_end(ap);
2848 sbuf_finish(sb);
2849 len = sbuf_len(sb) + 1;
2850 maa = malloc(sizeof *maa + len, M_MOUNT, M_WAITOK | M_ZERO);
2851 SLIST_INSERT_HEAD(&ma->list, maa, next);
2852 bcopy(sbuf_data(sb), maa + 1, len);
2853 sbuf_delete(sb);
2854
2855 ma->v[ma->len].iov_base = maa + 1;
2856 ma->v[ma->len].iov_len = len;
2857 ma->len++;
2858
2859 return (ma);
2860 }
2861
2862 /*
2863 * Add an argument which is a userland string.
2864 */
2865 struct mntarg *
mount_argsu(struct mntarg * ma,const char * name,const void * val,int len)2866 mount_argsu(struct mntarg *ma, const char *name, const void *val, int len)
2867 {
2868 struct mntaarg *maa;
2869 char *tbuf;
2870
2871 if (val == NULL)
2872 return (ma);
2873 if (ma == NULL) {
2874 ma = malloc(sizeof *ma, M_MOUNT, M_WAITOK | M_ZERO);
2875 SLIST_INIT(&ma->list);
2876 }
2877 if (ma->error)
2878 return (ma);
2879 maa = malloc(sizeof *maa + len, M_MOUNT, M_WAITOK | M_ZERO);
2880 SLIST_INSERT_HEAD(&ma->list, maa, next);
2881 tbuf = (void *)(maa + 1);
2882 ma->error = copyinstr(val, tbuf, len, NULL);
2883 return (mount_arg(ma, name, tbuf, -1));
2884 }
2885
2886 /*
2887 * Plain argument.
2888 *
2889 * If length is -1, treat value as a C string.
2890 */
2891 struct mntarg *
mount_arg(struct mntarg * ma,const char * name,const void * val,int len)2892 mount_arg(struct mntarg *ma, const char *name, const void *val, int len)
2893 {
2894
2895 if (ma == NULL) {
2896 ma = malloc(sizeof *ma, M_MOUNT, M_WAITOK | M_ZERO);
2897 SLIST_INIT(&ma->list);
2898 }
2899 if (ma->error)
2900 return (ma);
2901
2902 ma->v = realloc(ma->v, sizeof *ma->v * (ma->len + 2),
2903 M_MOUNT, M_WAITOK);
2904 ma->v[ma->len].iov_base = (void *)(uintptr_t)name;
2905 ma->v[ma->len].iov_len = strlen(name) + 1;
2906 ma->len++;
2907
2908 ma->v[ma->len].iov_base = (void *)(uintptr_t)val;
2909 if (len < 0)
2910 ma->v[ma->len].iov_len = strlen(val) + 1;
2911 else
2912 ma->v[ma->len].iov_len = len;
2913 ma->len++;
2914 return (ma);
2915 }
2916
2917 /*
2918 * Free a mntarg structure
2919 */
2920 static void
free_mntarg(struct mntarg * ma)2921 free_mntarg(struct mntarg *ma)
2922 {
2923 struct mntaarg *maa;
2924
2925 while (!SLIST_EMPTY(&ma->list)) {
2926 maa = SLIST_FIRST(&ma->list);
2927 SLIST_REMOVE_HEAD(&ma->list, next);
2928 free(maa, M_MOUNT);
2929 }
2930 free(ma->v, M_MOUNT);
2931 free(ma, M_MOUNT);
2932 }
2933
2934 /*
2935 * Mount a filesystem
2936 */
2937 int
kernel_mount(struct mntarg * ma,uint64_t flags)2938 kernel_mount(struct mntarg *ma, uint64_t flags)
2939 {
2940 struct uio auio;
2941 int error;
2942
2943 KASSERT(ma != NULL, ("kernel_mount NULL ma"));
2944 KASSERT(ma->error != 0 || ma->v != NULL, ("kernel_mount NULL ma->v"));
2945 KASSERT(!(ma->len & 1), ("kernel_mount odd ma->len (%d)", ma->len));
2946
2947 error = ma->error;
2948 if (error == 0) {
2949 auio.uio_iov = ma->v;
2950 auio.uio_iovcnt = ma->len;
2951 auio.uio_segflg = UIO_SYSSPACE;
2952 error = vfs_donmount(curthread, flags, &auio);
2953 }
2954 free_mntarg(ma);
2955 return (error);
2956 }
2957
2958 /* Map from mount options to printable formats. */
2959 static struct mntoptnames optnames[] = {
2960 MNTOPT_NAMES
2961 };
2962
2963 #define DEVCTL_LEN 1024
2964 static void
mount_devctl_event(const char * type,struct mount * mp,bool donew)2965 mount_devctl_event(const char *type, struct mount *mp, bool donew)
2966 {
2967 const uint8_t *cp;
2968 struct mntoptnames *fp;
2969 struct sbuf sb;
2970 struct statfs *sfp = &mp->mnt_stat;
2971 char *buf;
2972
2973 buf = malloc(DEVCTL_LEN, M_MOUNT, M_NOWAIT);
2974 if (buf == NULL)
2975 return;
2976 sbuf_new(&sb, buf, DEVCTL_LEN, SBUF_FIXEDLEN);
2977 sbuf_cpy(&sb, "mount-point=\"");
2978 devctl_safe_quote_sb(&sb, sfp->f_mntonname);
2979 sbuf_cat(&sb, "\" mount-dev=\"");
2980 devctl_safe_quote_sb(&sb, sfp->f_mntfromname);
2981 sbuf_cat(&sb, "\" mount-type=\"");
2982 devctl_safe_quote_sb(&sb, sfp->f_fstypename);
2983 sbuf_cat(&sb, "\" fsid=0x");
2984 cp = (const uint8_t *)&sfp->f_fsid.val[0];
2985 for (int i = 0; i < sizeof(sfp->f_fsid); i++)
2986 sbuf_printf(&sb, "%02x", cp[i]);
2987 sbuf_printf(&sb, " owner=%u flags=\"", sfp->f_owner);
2988 for (fp = optnames; fp->o_opt != 0; fp++) {
2989 if ((mp->mnt_flag & fp->o_opt) != 0) {
2990 sbuf_cat(&sb, fp->o_name);
2991 sbuf_putc(&sb, ';');
2992 }
2993 }
2994 sbuf_putc(&sb, '"');
2995 sbuf_finish(&sb);
2996
2997 /*
2998 * Options are not published because the form of the options depends on
2999 * the file system and may include binary data. In addition, they don't
3000 * necessarily provide enough useful information to be actionable when
3001 * devd processes them.
3002 */
3003
3004 if (sbuf_error(&sb) == 0)
3005 devctl_notify("VFS", "FS", type, sbuf_data(&sb));
3006 sbuf_delete(&sb);
3007 free(buf, M_MOUNT);
3008 }
3009
3010 /*
3011 * Force remount specified mount point to read-only. The argument
3012 * must be busied to avoid parallel unmount attempts.
3013 *
3014 * Intended use is to prevent further writes if some metadata
3015 * inconsistency is detected. Note that the function still flushes
3016 * all cached metadata and data for the mount point, which might be
3017 * not always suitable.
3018 */
3019 int
vfs_remount_ro(struct mount * mp)3020 vfs_remount_ro(struct mount *mp)
3021 {
3022 struct vfsoptlist *opts;
3023 struct vfsopt *opt;
3024 struct vnode *vp_covered, *rootvp;
3025 int error;
3026
3027 vfs_op_enter(mp);
3028 KASSERT(mp->mnt_lockref > 0,
3029 ("vfs_remount_ro: mp %p is not busied", mp));
3030 KASSERT((mp->mnt_kern_flag & MNTK_UNMOUNT) == 0,
3031 ("vfs_remount_ro: mp %p is being unmounted (and busy?)", mp));
3032
3033 rootvp = NULL;
3034 vp_covered = mp->mnt_vnodecovered;
3035 error = vget(vp_covered, LK_EXCLUSIVE | LK_NOWAIT);
3036 if (error != 0) {
3037 vfs_op_exit(mp);
3038 return (error);
3039 }
3040 VI_LOCK(vp_covered);
3041 if ((vp_covered->v_iflag & VI_MOUNT) != 0) {
3042 VI_UNLOCK(vp_covered);
3043 vput(vp_covered);
3044 vfs_op_exit(mp);
3045 return (EBUSY);
3046 }
3047 vp_covered->v_iflag |= VI_MOUNT;
3048 VI_UNLOCK(vp_covered);
3049 vn_seqc_write_begin(vp_covered);
3050
3051 MNT_ILOCK(mp);
3052 if ((mp->mnt_flag & MNT_RDONLY) != 0) {
3053 MNT_IUNLOCK(mp);
3054 error = EBUSY;
3055 goto out;
3056 }
3057 mp->mnt_flag |= MNT_UPDATE | MNT_FORCE | MNT_RDONLY;
3058 rootvp = vfs_cache_root_clear(mp);
3059 MNT_IUNLOCK(mp);
3060
3061 opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK | M_ZERO);
3062 TAILQ_INIT(opts);
3063 opt = malloc(sizeof(struct vfsopt), M_MOUNT, M_WAITOK | M_ZERO);
3064 opt->name = strdup("ro", M_MOUNT);
3065 opt->value = NULL;
3066 TAILQ_INSERT_TAIL(opts, opt, link);
3067 vfs_mergeopts(opts, mp->mnt_opt);
3068 mp->mnt_optnew = opts;
3069
3070 error = VFS_MOUNT(mp);
3071
3072 if (error == 0) {
3073 MNT_ILOCK(mp);
3074 mp->mnt_flag &= ~(MNT_UPDATE | MNT_FORCE);
3075 MNT_IUNLOCK(mp);
3076 vfs_deallocate_syncvnode(mp);
3077 if (mp->mnt_opt != NULL)
3078 vfs_freeopts(mp->mnt_opt);
3079 mp->mnt_opt = mp->mnt_optnew;
3080 } else {
3081 MNT_ILOCK(mp);
3082 mp->mnt_flag &= ~(MNT_UPDATE | MNT_FORCE | MNT_RDONLY);
3083 MNT_IUNLOCK(mp);
3084 vfs_freeopts(mp->mnt_optnew);
3085 }
3086 mp->mnt_optnew = NULL;
3087
3088 out:
3089 vfs_op_exit(mp);
3090 VI_LOCK(vp_covered);
3091 vp_covered->v_iflag &= ~VI_MOUNT;
3092 VI_UNLOCK(vp_covered);
3093 vput(vp_covered);
3094 vn_seqc_write_end(vp_covered);
3095 if (rootvp != NULL) {
3096 vn_seqc_write_end(rootvp);
3097 vrele(rootvp);
3098 }
3099 return (error);
3100 }
3101
3102 /*
3103 * Suspend write operations on all local writeable filesystems. Does
3104 * full sync of them in the process.
3105 *
3106 * Iterate over the mount points in reverse order, suspending most
3107 * recently mounted filesystems first. It handles a case where a
3108 * filesystem mounted from a md(4) vnode-backed device should be
3109 * suspended before the filesystem that owns the vnode.
3110 */
3111 void
suspend_all_fs(void)3112 suspend_all_fs(void)
3113 {
3114 struct mount *mp;
3115 int error;
3116
3117 mtx_lock(&mountlist_mtx);
3118 TAILQ_FOREACH_REVERSE(mp, &mountlist, mntlist, mnt_list) {
3119 error = vfs_busy(mp, MBF_MNTLSTLOCK | MBF_NOWAIT);
3120 if (error != 0)
3121 continue;
3122 if ((mp->mnt_flag & (MNT_RDONLY | MNT_LOCAL)) != MNT_LOCAL ||
3123 (mp->mnt_kern_flag & MNTK_SUSPEND) != 0) {
3124 mtx_lock(&mountlist_mtx);
3125 vfs_unbusy(mp);
3126 continue;
3127 }
3128 error = vfs_write_suspend(mp, 0);
3129 if (error == 0) {
3130 MNT_ILOCK(mp);
3131 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND_ALL) == 0);
3132 mp->mnt_kern_flag |= MNTK_SUSPEND_ALL;
3133 MNT_IUNLOCK(mp);
3134 mtx_lock(&mountlist_mtx);
3135 } else {
3136 printf("suspend of %s failed, error %d\n",
3137 mp->mnt_stat.f_mntonname, error);
3138 mtx_lock(&mountlist_mtx);
3139 vfs_unbusy(mp);
3140 }
3141 }
3142 mtx_unlock(&mountlist_mtx);
3143 }
3144
3145 /*
3146 * Clone the mnt_exjail field to a new mount point.
3147 */
3148 void
vfs_exjail_clone(struct mount * inmp,struct mount * outmp)3149 vfs_exjail_clone(struct mount *inmp, struct mount *outmp)
3150 {
3151 struct ucred *cr;
3152 struct prison *pr;
3153
3154 MNT_ILOCK(inmp);
3155 cr = inmp->mnt_exjail;
3156 if (cr != NULL) {
3157 crhold(cr);
3158 MNT_IUNLOCK(inmp);
3159 pr = cr->cr_prison;
3160 sx_slock(&allprison_lock);
3161 if (!prison_isalive(pr)) {
3162 sx_sunlock(&allprison_lock);
3163 crfree(cr);
3164 return;
3165 }
3166 MNT_ILOCK(outmp);
3167 if (outmp->mnt_exjail == NULL) {
3168 outmp->mnt_exjail = cr;
3169 atomic_add_int(&pr->pr_exportcnt, 1);
3170 cr = NULL;
3171 }
3172 MNT_IUNLOCK(outmp);
3173 sx_sunlock(&allprison_lock);
3174 if (cr != NULL)
3175 crfree(cr);
3176 } else
3177 MNT_IUNLOCK(inmp);
3178 }
3179
3180 void
resume_all_fs(void)3181 resume_all_fs(void)
3182 {
3183 struct mount *mp;
3184
3185 mtx_lock(&mountlist_mtx);
3186 TAILQ_FOREACH(mp, &mountlist, mnt_list) {
3187 if ((mp->mnt_kern_flag & MNTK_SUSPEND_ALL) == 0)
3188 continue;
3189 mtx_unlock(&mountlist_mtx);
3190 MNT_ILOCK(mp);
3191 MPASS((mp->mnt_kern_flag & MNTK_SUSPEND) != 0);
3192 mp->mnt_kern_flag &= ~MNTK_SUSPEND_ALL;
3193 MNT_IUNLOCK(mp);
3194 vfs_write_resume(mp, 0);
3195 mtx_lock(&mountlist_mtx);
3196 vfs_unbusy(mp);
3197 }
3198 mtx_unlock(&mountlist_mtx);
3199 }
3200