xref: /freebsd/sys/fs/tmpfs/tmpfs_vfsops.c (revision 43d82295d28bacaa1cf8d1be9b89cc65fa6b2c33)
1 /*	$NetBSD: tmpfs_vfsops.c,v 1.10 2005/12/11 12:24:29 christos Exp $	*/
2 
3 /*-
4  * SPDX-License-Identifier: BSD-2-Clause-NetBSD
5  *
6  * Copyright (c) 2005 The NetBSD Foundation, Inc.
7  * All rights reserved.
8  *
9  * This code is derived from software contributed to The NetBSD Foundation
10  * by Julio M. Merino Vidal, developed as part of Google's Summer of Code
11  * 2005 program.
12  *
13  * Redistribution and use in source and binary forms, with or without
14  * modification, are permitted provided that the following conditions
15  * are met:
16  * 1. Redistributions of source code must retain the above copyright
17  *    notice, this list of conditions and the following disclaimer.
18  * 2. Redistributions in binary form must reproduce the above copyright
19  *    notice, this list of conditions and the following disclaimer in the
20  *    documentation and/or other materials provided with the distribution.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
24  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
25  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
26  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
27  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
28  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
29  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
30  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
31  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
32  * POSSIBILITY OF SUCH DAMAGE.
33  */
34 
35 /*
36  * Efficient memory file system.
37  *
38  * tmpfs is a file system that uses FreeBSD's virtual memory
39  * sub-system to store file data and metadata in an efficient way.
40  * This means that it does not follow the structure of an on-disk file
41  * system because it simply does not need to.  Instead, it uses
42  * memory-specific data structures and algorithms to automatically
43  * allocate and release resources.
44  */
45 
46 #include "opt_ddb.h"
47 #include "opt_tmpfs.h"
48 
49 #include <sys/cdefs.h>
50 __FBSDID("$FreeBSD$");
51 
52 #include <sys/param.h>
53 #include <sys/systm.h>
54 #include <sys/dirent.h>
55 #include <sys/file.h>
56 #include <sys/limits.h>
57 #include <sys/lock.h>
58 #include <sys/mount.h>
59 #include <sys/mutex.h>
60 #include <sys/proc.h>
61 #include <sys/jail.h>
62 #include <sys/kernel.h>
63 #include <sys/rwlock.h>
64 #include <sys/stat.h>
65 #include <sys/sx.h>
66 #include <sys/sysctl.h>
67 #include <sys/vnode.h>
68 
69 #include <vm/vm.h>
70 #include <vm/vm_param.h>
71 #include <vm/pmap.h>
72 #include <vm/vm_extern.h>
73 #include <vm/vm_map.h>
74 #include <vm/vm_object.h>
75 #include <vm/vm_param.h>
76 
77 #include <fs/tmpfs/tmpfs.h>
78 
79 /*
80  * Default permission for root node
81  */
82 #define TMPFS_DEFAULT_ROOT_MODE	(S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
83 
84 static MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures");
85 MALLOC_DEFINE(M_TMPFSNAME, "tmpfs name", "tmpfs file names");
86 
87 static int	tmpfs_mount(struct mount *);
88 static int	tmpfs_unmount(struct mount *, int);
89 static int	tmpfs_root(struct mount *, int flags, struct vnode **);
90 static int	tmpfs_fhtovp(struct mount *, struct fid *, int,
91 		    struct vnode **);
92 static int	tmpfs_statfs(struct mount *, struct statfs *);
93 
94 static const char *tmpfs_opts[] = {
95 	"from", "size", "maxfilesize", "inodes", "uid", "gid", "mode", "export",
96 	"union", "nonc", "nomtime", NULL
97 };
98 
99 static const char *tmpfs_updateopts[] = {
100 	"from", "export", "nomtime", "size", NULL
101 };
102 
103 static int
104 tmpfs_update_mtime_lazy_filter(struct vnode *vp, void *arg)
105 {
106 	struct vm_object *obj;
107 
108 	if (vp->v_type != VREG)
109 		return (0);
110 
111 	obj = atomic_load_ptr(&vp->v_object);
112 	if (obj == NULL)
113 		return (0);
114 
115 	return (vm_object_mightbedirty_(obj));
116 }
117 
118 static void
119 tmpfs_update_mtime_lazy(struct mount *mp)
120 {
121 	struct vnode *vp, *mvp;
122 
123 	MNT_VNODE_FOREACH_LAZY(vp, mp, mvp, tmpfs_update_mtime_lazy_filter, NULL) {
124 		if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK) != 0)
125 			continue;
126 		tmpfs_check_mtime(vp);
127 		vput(vp);
128 	}
129 }
130 
131 static void
132 tmpfs_update_mtime_all(struct mount *mp)
133 {
134 	struct vnode *vp, *mvp;
135 
136 	if (VFS_TO_TMPFS(mp)->tm_nomtime)
137 		return;
138 	MNT_VNODE_FOREACH_ALL(vp, mp, mvp) {
139 		if (vp->v_type != VREG) {
140 			VI_UNLOCK(vp);
141 			continue;
142 		}
143 		if (vget(vp, LK_EXCLUSIVE | LK_INTERLOCK) != 0)
144 			continue;
145 		tmpfs_check_mtime(vp);
146 		tmpfs_update(vp);
147 		vput(vp);
148 	}
149 }
150 
151 struct tmpfs_check_rw_maps_arg {
152 	bool found;
153 };
154 
155 static bool
156 tmpfs_check_rw_maps_cb(struct mount *mp __unused, vm_map_t map __unused,
157     vm_map_entry_t entry __unused, void *arg)
158 {
159 	struct tmpfs_check_rw_maps_arg *a;
160 
161 	a = arg;
162 	a->found = true;
163 	return (true);
164 }
165 
166 /*
167  * Revoke write permissions from all mappings of regular files
168  * belonging to the specified tmpfs mount.
169  */
170 static bool
171 tmpfs_revoke_rw_maps_cb(struct mount *mp __unused, vm_map_t map,
172     vm_map_entry_t entry, void *arg __unused)
173 {
174 
175 	/*
176 	 * XXXKIB: might be invalidate the mapping
177 	 * instead ?  The process is not going to be
178 	 * happy in any case.
179 	 */
180 	entry->max_protection &= ~VM_PROT_WRITE;
181 	if ((entry->protection & VM_PROT_WRITE) != 0) {
182 		entry->protection &= ~VM_PROT_WRITE;
183 		pmap_protect(map->pmap, entry->start, entry->end,
184 		    entry->protection);
185 	}
186 	return (false);
187 }
188 
189 static void
190 tmpfs_all_rw_maps(struct mount *mp, bool (*cb)(struct mount *mp, vm_map_t,
191     vm_map_entry_t, void *), void *cb_arg)
192 {
193 	struct proc *p;
194 	struct vmspace *vm;
195 	vm_map_t map;
196 	vm_map_entry_t entry;
197 	vm_object_t object;
198 	struct vnode *vp;
199 	int gen;
200 	bool terminate;
201 
202 	terminate = false;
203 	sx_slock(&allproc_lock);
204 again:
205 	gen = allproc_gen;
206 	FOREACH_PROC_IN_SYSTEM(p) {
207 		PROC_LOCK(p);
208 		if (p->p_state != PRS_NORMAL || (p->p_flag & (P_INEXEC |
209 		    P_SYSTEM | P_WEXIT)) != 0) {
210 			PROC_UNLOCK(p);
211 			continue;
212 		}
213 		vm = vmspace_acquire_ref(p);
214 		_PHOLD_LITE(p);
215 		PROC_UNLOCK(p);
216 		if (vm == NULL) {
217 			PRELE(p);
218 			continue;
219 		}
220 		sx_sunlock(&allproc_lock);
221 		map = &vm->vm_map;
222 
223 		vm_map_lock(map);
224 		if (map->busy)
225 			vm_map_wait_busy(map);
226 		VM_MAP_ENTRY_FOREACH(entry, map) {
227 			if ((entry->eflags & (MAP_ENTRY_GUARD |
228 			    MAP_ENTRY_IS_SUB_MAP | MAP_ENTRY_COW)) != 0 ||
229 			    (entry->max_protection & VM_PROT_WRITE) == 0)
230 				continue;
231 			object = entry->object.vm_object;
232 			if (object == NULL || object->type != tmpfs_pager_type)
233 				continue;
234 			/*
235 			 * No need to dig into shadow chain, mapping
236 			 * of the object not at top is readonly.
237 			 */
238 
239 			VM_OBJECT_RLOCK(object);
240 			if (object->type == OBJT_DEAD) {
241 				VM_OBJECT_RUNLOCK(object);
242 				continue;
243 			}
244 			MPASS(object->ref_count > 1);
245 			if ((object->flags & OBJ_TMPFS) == 0) {
246 				VM_OBJECT_RUNLOCK(object);
247 				continue;
248 			}
249 			vp = VM_TO_TMPFS_VP(object);
250 			if (vp->v_mount != mp) {
251 				VM_OBJECT_RUNLOCK(object);
252 				continue;
253 			}
254 
255 			terminate = cb(mp, map, entry, cb_arg);
256 			VM_OBJECT_RUNLOCK(object);
257 			if (terminate)
258 				break;
259 		}
260 		vm_map_unlock(map);
261 
262 		vmspace_free(vm);
263 		sx_slock(&allproc_lock);
264 		PRELE(p);
265 		if (terminate)
266 			break;
267 	}
268 	if (!terminate && gen != allproc_gen)
269 		goto again;
270 	sx_sunlock(&allproc_lock);
271 }
272 
273 static bool
274 tmpfs_check_rw_maps(struct mount *mp)
275 {
276 	struct tmpfs_check_rw_maps_arg ca;
277 
278 	ca.found = false;
279 	tmpfs_all_rw_maps(mp, tmpfs_check_rw_maps_cb, &ca);
280 	return (ca.found);
281 }
282 
283 static int
284 tmpfs_rw_to_ro(struct mount *mp)
285 {
286 	int error, flags;
287 	bool forced;
288 
289 	forced = (mp->mnt_flag & MNT_FORCE) != 0;
290 	flags = WRITECLOSE | (forced ? FORCECLOSE : 0);
291 
292 	if ((error = vn_start_write(NULL, &mp, V_WAIT)) != 0)
293 		return (error);
294 	error = vfs_write_suspend_umnt(mp);
295 	if (error != 0)
296 		return (error);
297 	if (!forced && tmpfs_check_rw_maps(mp)) {
298 		error = EBUSY;
299 		goto out;
300 	}
301 	VFS_TO_TMPFS(mp)->tm_ronly = 1;
302 	MNT_ILOCK(mp);
303 	mp->mnt_flag |= MNT_RDONLY;
304 	MNT_IUNLOCK(mp);
305 	for (;;) {
306 		tmpfs_all_rw_maps(mp, tmpfs_revoke_rw_maps_cb, NULL);
307 		tmpfs_update_mtime_all(mp);
308 		error = vflush(mp, 0, flags, curthread);
309 		if (error != 0) {
310 			VFS_TO_TMPFS(mp)->tm_ronly = 0;
311 			MNT_ILOCK(mp);
312 			mp->mnt_flag &= ~MNT_RDONLY;
313 			MNT_IUNLOCK(mp);
314 			goto out;
315 		}
316 		if (!tmpfs_check_rw_maps(mp))
317 			break;
318 	}
319 out:
320 	vfs_write_resume(mp, 0);
321 	return (error);
322 }
323 
324 static int
325 tmpfs_mount(struct mount *mp)
326 {
327 	const size_t nodes_per_page = howmany(PAGE_SIZE,
328 	    sizeof(struct tmpfs_dirent) + sizeof(struct tmpfs_node));
329 	struct tmpfs_mount *tmp;
330 	struct tmpfs_node *root;
331 	int error;
332 	bool nomtime, nonc;
333 	/* Size counters. */
334 	u_quad_t pages;
335 	off_t nodes_max, size_max, maxfilesize;
336 
337 	/* Root node attributes. */
338 	uid_t root_uid;
339 	gid_t root_gid;
340 	mode_t root_mode;
341 
342 	struct vattr va;
343 
344 	if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts))
345 		return (EINVAL);
346 
347 	if (mp->mnt_flag & MNT_UPDATE) {
348 		/* Only support update mounts for certain options. */
349 		if (vfs_filteropt(mp->mnt_optnew, tmpfs_updateopts) != 0)
350 			return (EOPNOTSUPP);
351 		tmp = VFS_TO_TMPFS(mp);
352 		if (vfs_getopt_size(mp->mnt_optnew, "size", &size_max) == 0) {
353 			/*
354 			 * On-the-fly resizing is not supported (yet). We still
355 			 * need to have "size" listed as "supported", otherwise
356 			 * trying to update fs that is listed in fstab with size
357 			 * parameter, say trying to change rw to ro or vice
358 			 * versa, would cause vfs_filteropt() to bail.
359 			 */
360 			if (size_max != tmp->tm_size_max)
361 				return (EOPNOTSUPP);
362 		}
363 		if (vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0) &&
364 		    !tmp->tm_ronly) {
365 			/* RW -> RO */
366 			return (tmpfs_rw_to_ro(mp));
367 		} else if (!vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0) &&
368 		    tmp->tm_ronly) {
369 			/* RO -> RW */
370 			tmp->tm_ronly = 0;
371 			MNT_ILOCK(mp);
372 			mp->mnt_flag &= ~MNT_RDONLY;
373 			MNT_IUNLOCK(mp);
374 		}
375 		tmp->tm_nomtime = vfs_getopt(mp->mnt_optnew, "nomtime", NULL,
376 		    0) == 0;
377 		MNT_ILOCK(mp);
378 		if ((mp->mnt_flag & MNT_UNION) == 0) {
379 			mp->mnt_kern_flag |= MNTK_FPLOOKUP;
380 		} else {
381 			mp->mnt_kern_flag &= ~MNTK_FPLOOKUP;
382 		}
383 		MNT_IUNLOCK(mp);
384 		return (0);
385 	}
386 
387 	vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
388 	error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred);
389 	VOP_UNLOCK(mp->mnt_vnodecovered);
390 	if (error)
391 		return (error);
392 
393 	if (mp->mnt_cred->cr_ruid != 0 ||
394 	    vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1)
395 		root_gid = va.va_gid;
396 	if (mp->mnt_cred->cr_ruid != 0 ||
397 	    vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1)
398 		root_uid = va.va_uid;
399 	if (mp->mnt_cred->cr_ruid != 0 ||
400 	    vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1)
401 		root_mode = va.va_mode;
402 	if (vfs_getopt_size(mp->mnt_optnew, "inodes", &nodes_max) != 0)
403 		nodes_max = 0;
404 	if (vfs_getopt_size(mp->mnt_optnew, "size", &size_max) != 0)
405 		size_max = 0;
406 	if (vfs_getopt_size(mp->mnt_optnew, "maxfilesize", &maxfilesize) != 0)
407 		maxfilesize = 0;
408 	nonc = vfs_getopt(mp->mnt_optnew, "nonc", NULL, NULL) == 0;
409 	nomtime = vfs_getopt(mp->mnt_optnew, "nomtime", NULL, NULL) == 0;
410 
411 	/* Do not allow mounts if we do not have enough memory to preserve
412 	 * the minimum reserved pages. */
413 	if (tmpfs_mem_avail() < TMPFS_PAGES_MINRESERVED)
414 		return (ENOSPC);
415 
416 	/* Get the maximum number of memory pages this file system is
417 	 * allowed to use, based on the maximum size the user passed in
418 	 * the mount structure.  A value of zero is treated as if the
419 	 * maximum available space was requested. */
420 	if (size_max == 0 || size_max > OFF_MAX - PAGE_SIZE ||
421 	    (SIZE_MAX < OFF_MAX && size_max / PAGE_SIZE >= SIZE_MAX))
422 		pages = SIZE_MAX;
423 	else {
424 		size_max = roundup(size_max, PAGE_SIZE);
425 		pages = howmany(size_max, PAGE_SIZE);
426 	}
427 	MPASS(pages > 0);
428 
429 	if (nodes_max <= 3) {
430 		if (pages < INT_MAX / nodes_per_page)
431 			nodes_max = pages * nodes_per_page;
432 		else
433 			nodes_max = INT_MAX;
434 	}
435 	if (nodes_max > INT_MAX)
436 		nodes_max = INT_MAX;
437 	MPASS(nodes_max >= 3);
438 
439 	/* Allocate the tmpfs mount structure and fill it. */
440 	tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount),
441 	    M_TMPFSMNT, M_WAITOK | M_ZERO);
442 
443 	mtx_init(&tmp->tm_allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF);
444 	tmp->tm_nodes_max = nodes_max;
445 	tmp->tm_nodes_inuse = 0;
446 	tmp->tm_refcount = 1;
447 	tmp->tm_maxfilesize = maxfilesize > 0 ? maxfilesize : OFF_MAX;
448 	LIST_INIT(&tmp->tm_nodes_used);
449 
450 	tmp->tm_size_max = size_max;
451 	tmp->tm_pages_max = pages;
452 	tmp->tm_pages_used = 0;
453 	new_unrhdr64(&tmp->tm_ino_unr, 2);
454 	tmp->tm_ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
455 	tmp->tm_nonc = nonc;
456 	tmp->tm_nomtime = nomtime;
457 
458 	/* Allocate the root node. */
459 	error = tmpfs_alloc_node(mp, tmp, VDIR, root_uid, root_gid,
460 	    root_mode & ALLPERMS, NULL, NULL, VNOVAL, &root);
461 
462 	if (error != 0 || root == NULL) {
463 		free(tmp, M_TMPFSMNT);
464 		return (error);
465 	}
466 	KASSERT(root->tn_id == 2,
467 	    ("tmpfs root with invalid ino: %ju", (uintmax_t)root->tn_id));
468 	tmp->tm_root = root;
469 
470 	MNT_ILOCK(mp);
471 	mp->mnt_flag |= MNT_LOCAL;
472 	mp->mnt_kern_flag |= MNTK_LOOKUP_SHARED | MNTK_EXTENDED_SHARED |
473 	    MNTK_NOMSYNC;
474 	if (!nonc && (mp->mnt_flag & MNT_UNION) == 0)
475 		mp->mnt_kern_flag |= MNTK_FPLOOKUP;
476 	MNT_IUNLOCK(mp);
477 
478 	mp->mnt_data = tmp;
479 	mp->mnt_stat.f_namemax = MAXNAMLEN;
480 	vfs_getnewfsid(mp);
481 	vfs_mountedfrom(mp, "tmpfs");
482 
483 	return (0);
484 }
485 
486 /* ARGSUSED2 */
487 static int
488 tmpfs_unmount(struct mount *mp, int mntflags)
489 {
490 	struct tmpfs_mount *tmp;
491 	struct tmpfs_node *node;
492 	int error, flags;
493 
494 	flags = (mntflags & MNT_FORCE) != 0 ? FORCECLOSE : 0;
495 	tmp = VFS_TO_TMPFS(mp);
496 
497 	/* Stop writers */
498 	error = vfs_write_suspend_umnt(mp);
499 	if (error != 0)
500 		return (error);
501 	/*
502 	 * At this point, nodes cannot be destroyed by any other
503 	 * thread because write suspension is started.
504 	 */
505 
506 	for (;;) {
507 		error = vflush(mp, 0, flags, curthread);
508 		if (error != 0) {
509 			vfs_write_resume(mp, VR_START_WRITE);
510 			return (error);
511 		}
512 		MNT_ILOCK(mp);
513 		if (mp->mnt_nvnodelistsize == 0) {
514 			MNT_IUNLOCK(mp);
515 			break;
516 		}
517 		MNT_IUNLOCK(mp);
518 		if ((mntflags & MNT_FORCE) == 0) {
519 			vfs_write_resume(mp, VR_START_WRITE);
520 			return (EBUSY);
521 		}
522 	}
523 
524 	TMPFS_LOCK(tmp);
525 	while ((node = LIST_FIRST(&tmp->tm_nodes_used)) != NULL) {
526 		TMPFS_NODE_LOCK(node);
527 		if (node->tn_type == VDIR)
528 			tmpfs_dir_destroy(tmp, node);
529 		if (tmpfs_free_node_locked(tmp, node, true))
530 			TMPFS_LOCK(tmp);
531 		else
532 			TMPFS_NODE_UNLOCK(node);
533 	}
534 
535 	mp->mnt_data = NULL;
536 	tmpfs_free_tmp(tmp);
537 	vfs_write_resume(mp, VR_START_WRITE);
538 
539 	MNT_ILOCK(mp);
540 	mp->mnt_flag &= ~MNT_LOCAL;
541 	MNT_IUNLOCK(mp);
542 
543 	return (0);
544 }
545 
546 void
547 tmpfs_free_tmp(struct tmpfs_mount *tmp)
548 {
549 	TMPFS_MP_ASSERT_LOCKED(tmp);
550 	MPASS(tmp->tm_refcount > 0);
551 
552 	tmp->tm_refcount--;
553 	if (tmp->tm_refcount > 0) {
554 		TMPFS_UNLOCK(tmp);
555 		return;
556 	}
557 	TMPFS_UNLOCK(tmp);
558 
559 	mtx_destroy(&tmp->tm_allnode_lock);
560 	/*
561 	 * We cannot assert that tmp->tm_pages_used == 0 there,
562 	 * because tmpfs vm_objects might be still mapped by some
563 	 * process and outlive the mount due to reference counting.
564 	 */
565 	MPASS(tmp->tm_nodes_inuse == 0);
566 
567 	free(tmp, M_TMPFSMNT);
568 }
569 
570 static int
571 tmpfs_root(struct mount *mp, int flags, struct vnode **vpp)
572 {
573 	int error;
574 
575 	error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp);
576 	if (error == 0)
577 		(*vpp)->v_vflag |= VV_ROOT;
578 	return (error);
579 }
580 
581 static int
582 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int flags,
583     struct vnode **vpp)
584 {
585 	struct tmpfs_fid_data tfd;
586 	struct tmpfs_mount *tmp;
587 	struct tmpfs_node *node;
588 	int error;
589 
590 	if (fhp->fid_len != sizeof(tfd))
591 		return (EINVAL);
592 
593 	/*
594 	 * Copy from fid_data onto the stack to avoid unaligned pointer use.
595 	 * See the comment in sys/mount.h on struct fid for details.
596 	 */
597 	memcpy(&tfd, fhp->fid_data, fhp->fid_len);
598 
599 	tmp = VFS_TO_TMPFS(mp);
600 
601 	if (tfd.tfd_id >= tmp->tm_nodes_max)
602 		return (EINVAL);
603 
604 	TMPFS_LOCK(tmp);
605 	LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
606 		if (node->tn_id == tfd.tfd_id &&
607 		    node->tn_gen == tfd.tfd_gen) {
608 			tmpfs_ref_node(node);
609 			break;
610 		}
611 	}
612 	TMPFS_UNLOCK(tmp);
613 
614 	if (node != NULL) {
615 		error = tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp);
616 		tmpfs_free_node(tmp, node);
617 	} else
618 		error = EINVAL;
619 	return (error);
620 }
621 
622 /* ARGSUSED2 */
623 static int
624 tmpfs_statfs(struct mount *mp, struct statfs *sbp)
625 {
626 	struct tmpfs_mount *tmp;
627 	size_t used;
628 
629 	tmp = VFS_TO_TMPFS(mp);
630 
631 	sbp->f_iosize = PAGE_SIZE;
632 	sbp->f_bsize = PAGE_SIZE;
633 
634 	used = tmpfs_pages_used(tmp);
635 	if (tmp->tm_pages_max != ULONG_MAX)
636 		 sbp->f_blocks = tmp->tm_pages_max;
637 	else
638 		 sbp->f_blocks = used + tmpfs_mem_avail();
639 	if (sbp->f_blocks <= used)
640 		sbp->f_bavail = 0;
641 	else
642 		sbp->f_bavail = sbp->f_blocks - used;
643 	sbp->f_bfree = sbp->f_bavail;
644 	used = tmp->tm_nodes_inuse;
645 	sbp->f_files = tmp->tm_nodes_max;
646 	if (sbp->f_files <= used)
647 		sbp->f_ffree = 0;
648 	else
649 		sbp->f_ffree = sbp->f_files - used;
650 	/* sbp->f_owner = tmp->tn_uid; */
651 
652 	return (0);
653 }
654 
655 static int
656 tmpfs_sync(struct mount *mp, int waitfor)
657 {
658 
659 	if (waitfor == MNT_SUSPEND) {
660 		MNT_ILOCK(mp);
661 		mp->mnt_kern_flag |= MNTK_SUSPEND2 | MNTK_SUSPENDED;
662 		MNT_IUNLOCK(mp);
663 	} else if (waitfor == MNT_LAZY) {
664 		tmpfs_update_mtime_lazy(mp);
665 	}
666 	return (0);
667 }
668 
669 static int
670 tmpfs_init(struct vfsconf *conf)
671 {
672 	int res;
673 
674 	res = tmpfs_subr_init();
675 	if (res != 0)
676 		return (res);
677 	memcpy(&tmpfs_fnops, &vnops, sizeof(struct fileops));
678 	tmpfs_fnops.fo_close = tmpfs_fo_close;
679 	return (0);
680 }
681 
682 static int
683 tmpfs_uninit(struct vfsconf *conf)
684 {
685 	tmpfs_subr_uninit();
686 	return (0);
687 }
688 
689 /*
690  * tmpfs vfs operations.
691  */
692 struct vfsops tmpfs_vfsops = {
693 	.vfs_mount =			tmpfs_mount,
694 	.vfs_unmount =			tmpfs_unmount,
695 	.vfs_root =			vfs_cache_root,
696 	.vfs_cachedroot =		tmpfs_root,
697 	.vfs_statfs =			tmpfs_statfs,
698 	.vfs_fhtovp =			tmpfs_fhtovp,
699 	.vfs_sync =			tmpfs_sync,
700 	.vfs_init =			tmpfs_init,
701 	.vfs_uninit =			tmpfs_uninit,
702 };
703 VFS_SET(tmpfs_vfsops, tmpfs, VFCF_JAIL);
704 
705 #ifdef DDB
706 #include <ddb/ddb.h>
707 
708 static void
709 db_print_tmpfs(struct mount *mp, struct tmpfs_mount *tmp)
710 {
711 	db_printf("mp %p (%s) tmp %p\n", mp,
712 	    mp->mnt_stat.f_mntonname, tmp);
713 	db_printf(
714 	    "\tsize max %ju pages max %lu pages used %lu\n"
715 	    "\tinodes max %ju inodes inuse %ju refcount %ju\n"
716 	    "\tmaxfilesize %ju r%c %snamecache %smtime\n",
717 	    (uintmax_t)tmp->tm_size_max, tmp->tm_pages_max, tmp->tm_pages_used,
718 	    (uintmax_t)tmp->tm_nodes_max, (uintmax_t)tmp->tm_nodes_inuse,
719 	    (uintmax_t)tmp->tm_refcount, (uintmax_t)tmp->tm_maxfilesize,
720 	    tmp->tm_ronly ? 'o' : 'w', tmp->tm_nonc ? "no" : "",
721 	    tmp->tm_nomtime ? "no" : "");
722 }
723 
724 DB_SHOW_COMMAND(tmpfs, db_show_tmpfs)
725 {
726 	struct mount *mp;
727 	struct tmpfs_mount *tmp;
728 
729 	if (have_addr) {
730 		mp = (struct mount *)addr;
731 		tmp = VFS_TO_TMPFS(mp);
732 		db_print_tmpfs(mp, tmp);
733 		return;
734 	}
735 
736 	TAILQ_FOREACH(mp, &mountlist, mnt_list) {
737 		if (strcmp(mp->mnt_stat.f_fstypename, tmpfs_vfsconf.vfc_name) ==
738 		    0) {
739 			tmp = VFS_TO_TMPFS(mp);
740 			db_print_tmpfs(mp, tmp);
741 		}
742 	}
743 }
744 #endif	/* DDB */
745