xref: /freebsd/sys/fs/tmpfs/tmpfs_vfsops.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
1 /*	$NetBSD: tmpfs_vfsops.c,v 1.10 2005/12/11 12:24:29 christos Exp $	*/
2 
3 /*
4  * Copyright (c) 2005 The NetBSD Foundation, Inc.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to The NetBSD Foundation
8  * by Julio M. Merino Vidal, developed as part of Google's Summer of Code
9  * 2005 program.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *        This product includes software developed by the NetBSD
22  *        Foundation, Inc. and its contributors.
23  * 4. Neither the name of The NetBSD Foundation nor the names of its
24  *    contributors may be used to endorse or promote products derived
25  *    from this software without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
37  * POSSIBILITY OF SUCH DAMAGE.
38  */
39 
40 /*
41  * Efficient memory file system.
42  *
43  * tmpfs is a file system that uses NetBSD's virtual memory sub-system
44  * (the well-known UVM) to store file data and metadata in an efficient
45  * way.  This means that it does not follow the structure of an on-disk
46  * file system because it simply does not need to.  Instead, it uses
47  * memory-specific data structures and algorithms to automatically
48  * allocate and release resources.
49  */
50 #include <sys/cdefs.h>
51 __FBSDID("$FreeBSD$");
52 
53 #include <sys/param.h>
54 #include <sys/limits.h>
55 #include <sys/lock.h>
56 #include <sys/mutex.h>
57 #include <sys/kernel.h>
58 #include <sys/stat.h>
59 #include <sys/systm.h>
60 #include <sys/sysctl.h>
61 
62 #include <vm/vm.h>
63 #include <vm/vm_object.h>
64 #include <vm/vm_param.h>
65 
66 #include <fs/tmpfs/tmpfs.h>
67 
68 /*
69  * Default permission for root node
70  */
71 #define TMPFS_DEFAULT_ROOT_MODE	(S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
72 
73 MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures");
74 MALLOC_DEFINE(M_TMPFSNAME, "tmpfs name", "tmpfs file names");
75 
76 /* --------------------------------------------------------------------- */
77 
78 static int	tmpfs_mount(struct mount *, struct thread *);
79 static int	tmpfs_unmount(struct mount *, int, struct thread *);
80 static int	tmpfs_root(struct mount *, int flags, struct vnode **,
81 		    struct thread *);
82 static int	tmpfs_fhtovp(struct mount *, struct fid *, struct vnode **);
83 static int	tmpfs_statfs(struct mount *, struct statfs *, struct thread *);
84 
85 /* --------------------------------------------------------------------- */
86 
87 static const char *tmpfs_opts[] = {
88 	"from", "size", "inodes", "uid", "gid", "mode", "export",
89 	NULL
90 };
91 
92 /* --------------------------------------------------------------------- */
93 
94 #define SWI_MAXMIB	3
95 
96 static u_int
97 get_swpgtotal(void)
98 {
99 	struct xswdev xsd;
100 	char *sname = "vm.swap_info";
101 	int soid[SWI_MAXMIB], oid[2];
102 	u_int unswdev, total, dmmax, nswapdev;
103 	size_t mibi, len;
104 
105 	total = 0;
106 
107 	len = sizeof(dmmax);
108 	if (kernel_sysctlbyname(curthread, "vm.dmmax", &dmmax, &len,
109 				NULL, 0, NULL, 0) != 0)
110 		return total;
111 
112 	len = sizeof(nswapdev);
113 	if (kernel_sysctlbyname(curthread, "vm.nswapdev",
114 				&nswapdev, &len,
115 				NULL, 0, NULL, 0) != 0)
116 		return total;
117 
118 	mibi = (SWI_MAXMIB - 1) * sizeof(int);
119 	oid[0] = 0;
120 	oid[1] = 3;
121 
122 	if (kernel_sysctl(curthread, oid, 2,
123 			soid, &mibi, (void *)sname, strlen(sname),
124 			NULL, 0) != 0)
125 		return total;
126 
127 	mibi = (SWI_MAXMIB - 1);
128 	for (unswdev = 0; unswdev < nswapdev; ++unswdev) {
129 		soid[mibi] = unswdev;
130 		len = sizeof(struct xswdev);
131 		if (kernel_sysctl(curthread,
132 				soid, mibi + 1, &xsd, &len, NULL, 0,
133 				NULL, 0) != 0)
134 			return total;
135 		if (len == sizeof(struct xswdev))
136 			total += (xsd.xsw_nblks - dmmax);
137 	}
138 
139 	/* Not Reached */
140 	return total;
141 }
142 
143 /* --------------------------------------------------------------------- */
144 static int
145 tmpfs_node_ctor(void *mem, int size, void *arg, int flags)
146 {
147 	struct tmpfs_node *node = (struct tmpfs_node *)mem;
148 
149 	node->tn_gen++;
150 	node->tn_size = 0;
151 	node->tn_status = 0;
152 	node->tn_flags = 0;
153 	node->tn_links = 0;
154 	node->tn_lockf = NULL;
155 	node->tn_vnode = NULL;
156 	node->tn_vpstate = 0;
157 
158 	return (0);
159 }
160 
161 static void
162 tmpfs_node_dtor(void *mem, int size, void *arg)
163 {
164 	struct tmpfs_node *node = (struct tmpfs_node *)mem;
165 	node->tn_type = VNON;
166 }
167 
168 static int
169 tmpfs_node_init(void *mem, int size, int flags)
170 {
171 	struct tmpfs_node *node = (struct tmpfs_node *)mem;
172 	node->tn_id = 0;
173 
174 	mtx_init(&node->tn_interlock, "tmpfs node interlock", NULL, MTX_DEF);
175 	node->tn_gen = arc4random();
176 
177 	return (0);
178 }
179 
180 static void
181 tmpfs_node_fini(void *mem, int size)
182 {
183 	struct tmpfs_node *node = (struct tmpfs_node *)mem;
184 
185 	mtx_destroy(&node->tn_interlock);
186 }
187 
188 static int
189 tmpfs_mount(struct mount *mp, struct thread *td)
190 {
191 	struct tmpfs_mount *tmp;
192 	struct tmpfs_node *root;
193 	size_t pages, mem_size;
194 	ino_t nodes;
195 	int error;
196 	/* Size counters. */
197 	ino_t	nodes_max;
198 	size_t	size_max;
199 
200 	/* Root node attributes. */
201 	uid_t	root_uid;
202 	gid_t	root_gid;
203 	mode_t	root_mode;
204 
205 	struct vattr	va;
206 
207 	if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts))
208 		return (EINVAL);
209 
210 	if (mp->mnt_flag & MNT_UPDATE) {
211 		/* XXX: There is no support yet to update file system
212 		 * settings.  Should be added. */
213 
214 		return EOPNOTSUPP;
215 	}
216 
217 	printf("WARNING: TMPFS is considered to be a highly experimental "
218 	    "feature in FreeBSD.\n");
219 
220 	vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
221 	error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred, td);
222 	VOP_UNLOCK(mp->mnt_vnodecovered, 0);
223 	if (error)
224 		return (error);
225 
226 	if (mp->mnt_cred->cr_ruid != 0 ||
227 	    vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1)
228 		root_gid = va.va_gid;
229 	if (mp->mnt_cred->cr_ruid != 0 ||
230 	    vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1)
231 		root_uid = va.va_uid;
232 	if (mp->mnt_cred->cr_ruid != 0 ||
233 	    vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1)
234 		root_mode = va.va_mode;
235 	if (vfs_scanopt(mp->mnt_optnew, "inodes", "%d", &nodes_max) != 1)
236 		nodes_max = 0;
237 	if (vfs_scanopt(mp->mnt_optnew, "size", "%qu", &size_max) != 1)
238 		size_max = 0;
239 
240 	/* Do not allow mounts if we do not have enough memory to preserve
241 	 * the minimum reserved pages. */
242 	mem_size = cnt.v_free_count + cnt.v_inactive_count + get_swpgtotal();
243 	mem_size -= mem_size > cnt.v_wire_count ? cnt.v_wire_count : mem_size;
244 	if (mem_size < TMPFS_PAGES_RESERVED)
245 		return ENOSPC;
246 
247 	/* Get the maximum number of memory pages this file system is
248 	 * allowed to use, based on the maximum size the user passed in
249 	 * the mount structure.  A value of zero is treated as if the
250 	 * maximum available space was requested. */
251 	if (size_max < PAGE_SIZE || size_max >= SIZE_MAX)
252 		pages = SIZE_MAX;
253 	else
254 		pages = howmany(size_max, PAGE_SIZE);
255 	MPASS(pages > 0);
256 
257 	if (nodes_max <= 3)
258 		nodes = 3 + pages * PAGE_SIZE / 1024;
259 	else
260 		nodes = nodes_max;
261 	MPASS(nodes >= 3);
262 
263 	/* Allocate the tmpfs mount structure and fill it. */
264 	tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount),
265 	    M_TMPFSMNT, M_WAITOK | M_ZERO);
266 
267 	mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF);
268 	tmp->tm_nodes_max = nodes;
269 	tmp->tm_nodes_inuse = 0;
270 	tmp->tm_maxfilesize = (u_int64_t)(cnt.v_page_count + get_swpgtotal()) * PAGE_SIZE;
271 	LIST_INIT(&tmp->tm_nodes_used);
272 
273 	tmp->tm_pages_max = pages;
274 	tmp->tm_pages_used = 0;
275 	tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock);
276 	tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent",
277 	    sizeof(struct tmpfs_dirent),
278 	    NULL, NULL, NULL, NULL,
279 	    UMA_ALIGN_PTR, 0);
280 	tmp->tm_node_pool = uma_zcreate("TMPFS node",
281 	    sizeof(struct tmpfs_node),
282 	    tmpfs_node_ctor, tmpfs_node_dtor,
283 	    tmpfs_node_init, tmpfs_node_fini,
284 	    UMA_ALIGN_PTR, 0);
285 
286 	/* Allocate the root node. */
287 	error = tmpfs_alloc_node(tmp, VDIR, root_uid,
288 	    root_gid, root_mode & ALLPERMS, NULL, NULL,
289 	    VNOVAL, td, &root);
290 
291 	if (error != 0 || root == NULL) {
292 	    uma_zdestroy(tmp->tm_node_pool);
293 	    uma_zdestroy(tmp->tm_dirent_pool);
294 	    delete_unrhdr(tmp->tm_ino_unr);
295 	    free(tmp, M_TMPFSMNT);
296 	    return error;
297 	}
298 	KASSERT(root->tn_id == 2, ("tmpfs root with invalid ino: %d", root->tn_id));
299 	tmp->tm_root = root;
300 
301 	MNT_ILOCK(mp);
302 	mp->mnt_flag |= MNT_LOCAL;
303 	mp->mnt_kern_flag |= MNTK_MPSAFE;
304 	MNT_IUNLOCK(mp);
305 
306 	mp->mnt_data = tmp;
307 	mp->mnt_stat.f_namemax = MAXNAMLEN;
308 	vfs_getnewfsid(mp);
309 	vfs_mountedfrom(mp, "tmpfs");
310 
311 	return 0;
312 }
313 
314 /* --------------------------------------------------------------------- */
315 
316 /* ARGSUSED2 */
317 static int
318 tmpfs_unmount(struct mount *mp, int mntflags, struct thread *l)
319 {
320 	int error;
321 	int flags = 0;
322 	struct tmpfs_mount *tmp;
323 	struct tmpfs_node *node;
324 
325 	/* Handle forced unmounts. */
326 	if (mntflags & MNT_FORCE)
327 		flags |= FORCECLOSE;
328 
329 	/* Finalize all pending I/O. */
330 	error = vflush(mp, 0, flags, l);
331 	if (error != 0)
332 		return error;
333 
334 	tmp = VFS_TO_TMPFS(mp);
335 
336 	/* Free all associated data.  The loop iterates over the linked list
337 	 * we have containing all used nodes.  For each of them that is
338 	 * a directory, we free all its directory entries.  Note that after
339 	 * freeing a node, it will automatically go to the available list,
340 	 * so we will later have to iterate over it to release its items. */
341 	node = LIST_FIRST(&tmp->tm_nodes_used);
342 	while (node != NULL) {
343 		struct tmpfs_node *next;
344 
345 		if (node->tn_type == VDIR) {
346 			struct tmpfs_dirent *de;
347 
348 			de = TAILQ_FIRST(&node->tn_dir.tn_dirhead);
349 			while (de != NULL) {
350 				struct tmpfs_dirent *nde;
351 
352 				nde = TAILQ_NEXT(de, td_entries);
353 				tmpfs_free_dirent(tmp, de, FALSE);
354 				de = nde;
355 				node->tn_size -= sizeof(struct tmpfs_dirent);
356 			}
357 		}
358 
359 		next = LIST_NEXT(node, tn_entries);
360 		tmpfs_free_node(tmp, node);
361 		node = next;
362 	}
363 
364 	uma_zdestroy(tmp->tm_dirent_pool);
365 	uma_zdestroy(tmp->tm_node_pool);
366 	delete_unrhdr(tmp->tm_ino_unr);
367 
368 	mtx_destroy(&tmp->allnode_lock);
369 	MPASS(tmp->tm_pages_used == 0);
370 	MPASS(tmp->tm_nodes_inuse == 0);
371 
372 	/* Throw away the tmpfs_mount structure. */
373 	free(mp->mnt_data, M_TMPFSMNT);
374 	mp->mnt_data = NULL;
375 
376 	MNT_ILOCK(mp);
377 	mp->mnt_flag &= ~MNT_LOCAL;
378 	MNT_IUNLOCK(mp);
379 	return 0;
380 }
381 
382 /* --------------------------------------------------------------------- */
383 
384 static int
385 tmpfs_root(struct mount *mp, int flags, struct vnode **vpp, struct thread *td)
386 {
387 	int error;
388 	error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp, td);
389 
390 	if (!error)
391 		(*vpp)->v_vflag |= VV_ROOT;
392 
393 	return error;
394 }
395 
396 /* --------------------------------------------------------------------- */
397 
398 static int
399 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
400 {
401 	boolean_t found;
402 	struct tmpfs_fid *tfhp;
403 	struct tmpfs_mount *tmp;
404 	struct tmpfs_node *node;
405 
406 	tmp = VFS_TO_TMPFS(mp);
407 
408 	tfhp = (struct tmpfs_fid *)fhp;
409 	if (tfhp->tf_len != sizeof(struct tmpfs_fid))
410 		return EINVAL;
411 
412 	if (tfhp->tf_id >= tmp->tm_nodes_max)
413 		return EINVAL;
414 
415 	found = FALSE;
416 
417 	TMPFS_LOCK(tmp);
418 	LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
419 		if (node->tn_id == tfhp->tf_id &&
420 		    node->tn_gen == tfhp->tf_gen) {
421 			found = TRUE;
422 			break;
423 		}
424 	}
425 	TMPFS_UNLOCK(tmp);
426 
427 	if (found)
428 		return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp, curthread));
429 
430 	return (EINVAL);
431 }
432 
433 /* --------------------------------------------------------------------- */
434 
435 /* ARGSUSED2 */
436 static int
437 tmpfs_statfs(struct mount *mp, struct statfs *sbp, struct thread *l)
438 {
439 	fsfilcnt_t freenodes;
440 	struct tmpfs_mount *tmp;
441 
442 	tmp = VFS_TO_TMPFS(mp);
443 
444 	sbp->f_iosize = PAGE_SIZE;
445 	sbp->f_bsize = PAGE_SIZE;
446 
447 	sbp->f_blocks = TMPFS_PAGES_MAX(tmp);
448 	sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp);
449 
450 	freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_inuse,
451 	    TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node));
452 
453 	sbp->f_files = freenodes + tmp->tm_nodes_inuse;
454 	sbp->f_ffree = freenodes;
455 	/* sbp->f_owner = tmp->tn_uid; */
456 
457 	return 0;
458 }
459 
460 /* --------------------------------------------------------------------- */
461 
462 /*
463  * tmpfs vfs operations.
464  */
465 
466 struct vfsops tmpfs_vfsops = {
467 	.vfs_mount =			tmpfs_mount,
468 	.vfs_unmount =			tmpfs_unmount,
469 	.vfs_root =			tmpfs_root,
470 	.vfs_statfs =			tmpfs_statfs,
471 	.vfs_fhtovp =			tmpfs_fhtovp,
472 };
473 VFS_SET(tmpfs_vfsops, tmpfs, 0);
474