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 *
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
31 */
32
33 /*
34 * Efficient memory file system.
35 *
36 * tmpfs is a file system that uses NetBSD's virtual memory sub-system
37 * (the well-known UVM) to store file data and metadata in an efficient
38 * way. This means that it does not follow the structure of an on-disk
39 * file system because it simply does not need to. Instead, it uses
40 * memory-specific data structures and algorithms to automatically
41 * allocate and release resources.
42 */
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD: releng/9.0/sys/fs/tmpfs/tmpfs_vfsops.c 222167 2011-05-22 01:07:54Z rmacklem $");
45
46 #include <sys/param.h>
47 #include <sys/limits.h>
48 #include <sys/lock.h>
49 #include <sys/mutex.h>
50 #include <sys/kernel.h>
51 #include <sys/stat.h>
52 #include <sys/systm.h>
53 #include <sys/sysctl.h>
54
55 #include <vm/vm.h>
56 #include <vm/vm_object.h>
57 #include <vm/vm_param.h>
58
59 #include <fs/tmpfs/tmpfs.h>
60
61 /*
62 * Default permission for root node
63 */
64 #define TMPFS_DEFAULT_ROOT_MODE (S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)
65
66 MALLOC_DEFINE(M_TMPFSMNT, "tmpfs mount", "tmpfs mount structures");
67 MALLOC_DEFINE(M_TMPFSNAME, "tmpfs name", "tmpfs file names");
68
69 /* --------------------------------------------------------------------- */
70
71 static int tmpfs_mount(struct mount *);
72 static int tmpfs_unmount(struct mount *, int);
73 static int tmpfs_root(struct mount *, int flags, struct vnode **);
74 static int tmpfs_fhtovp(struct mount *, struct fid *, int,
75 struct vnode **);
76 static int tmpfs_statfs(struct mount *, struct statfs *);
77
78 /* --------------------------------------------------------------------- */
79
80 static const char *tmpfs_opts[] = {
81 "from", "size", "maxfilesize", "inodes", "uid", "gid", "mode", "export",
82 NULL
83 };
84
85 /* --------------------------------------------------------------------- */
86
87 static int
88 tmpfs_node_ctor(void *mem, int size, void *arg, int flags)
89 {
90 struct tmpfs_node *node = (struct tmpfs_node *)mem;
91
92 node->tn_gen++;
93 node->tn_size = 0;
94 node->tn_status = 0;
95 node->tn_flags = 0;
96 node->tn_links = 0;
97 node->tn_vnode = NULL;
98 node->tn_vpstate = 0;
99
100 return (0);
101 }
102
103 static void
104 tmpfs_node_dtor(void *mem, int size, void *arg)
105 {
106 struct tmpfs_node *node = (struct tmpfs_node *)mem;
107 node->tn_type = VNON;
108 }
109
110 static int
111 tmpfs_node_init(void *mem, int size, int flags)
112 {
113 struct tmpfs_node *node = (struct tmpfs_node *)mem;
114 node->tn_id = 0;
115
116 mtx_init(&node->tn_interlock, "tmpfs node interlock", NULL, MTX_DEF);
117 node->tn_gen = arc4random();
118
119 return (0);
120 }
121
122 static void
123 tmpfs_node_fini(void *mem, int size)
124 {
125 struct tmpfs_node *node = (struct tmpfs_node *)mem;
126
127 mtx_destroy(&node->tn_interlock);
128 }
129
130 static int
131 tmpfs_mount(struct mount *mp)
132 {
133 struct tmpfs_mount *tmp;
134 struct tmpfs_node *root;
135 size_t pages;
136 uint32_t nodes;
137 int error;
138 /* Size counters. */
139 u_int nodes_max;
140 u_quad_t size_max, maxfilesize;
141
142 /* Root node attributes. */
143 uid_t root_uid;
144 gid_t root_gid;
145 mode_t root_mode;
146
147 struct vattr va;
148
149 if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts))
150 return (EINVAL);
151
152 if (mp->mnt_flag & MNT_UPDATE) {
153 /* XXX: There is no support yet to update file system
154 * settings. Should be added. */
155
156 return EOPNOTSUPP;
157 }
158
159 printf("WARNING: TMPFS is considered to be a highly experimental "
160 "feature in FreeBSD.\n");
161
162 vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
163 error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred);
164 VOP_UNLOCK(mp->mnt_vnodecovered, 0);
165 if (error)
166 return (error);
167
168 if (mp->mnt_cred->cr_ruid != 0 ||
169 vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1)
170 root_gid = va.va_gid;
171 if (mp->mnt_cred->cr_ruid != 0 ||
172 vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1)
173 root_uid = va.va_uid;
174 if (mp->mnt_cred->cr_ruid != 0 ||
175 vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1)
176 root_mode = va.va_mode;
177 if (vfs_scanopt(mp->mnt_optnew, "inodes", "%u", &nodes_max) != 1)
178 nodes_max = 0;
179 if (vfs_scanopt(mp->mnt_optnew, "size", "%qu", &size_max) != 1)
180 size_max = 0;
181 if (vfs_scanopt(mp->mnt_optnew, "maxfilesize", "%qu",
182 &maxfilesize) != 1)
183 maxfilesize = 0;
184
185 /* Do not allow mounts if we do not have enough memory to preserve
186 * the minimum reserved pages. */
187 if (tmpfs_mem_info() < TMPFS_PAGES_RESERVED)
188 return ENOSPC;
189
190 /* Get the maximum number of memory pages this file system is
191 * allowed to use, based on the maximum size the user passed in
192 * the mount structure. A value of zero is treated as if the
193 * maximum available space was requested. */
194 if (size_max < PAGE_SIZE || size_max > SIZE_MAX - PAGE_SIZE)
195 pages = SIZE_MAX;
196 else
197 pages = howmany(size_max, PAGE_SIZE);
198 MPASS(pages > 0);
199
200 if (nodes_max <= 3) {
201 if (pages > UINT32_MAX - 3)
202 nodes = UINT32_MAX;
203 else
204 nodes = pages + 3;
205 } else
206 nodes = nodes_max;
207 MPASS(nodes >= 3);
208
209 /* Allocate the tmpfs mount structure and fill it. */
210 tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount),
211 M_TMPFSMNT, M_WAITOK | M_ZERO);
212
213 mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF);
214 tmp->tm_nodes_max = nodes;
215 tmp->tm_nodes_inuse = 0;
216 tmp->tm_maxfilesize = maxfilesize > 0 ? maxfilesize : UINT64_MAX;
217 LIST_INIT(&tmp->tm_nodes_used);
218
219 tmp->tm_pages_max = pages;
220 tmp->tm_pages_used = 0;
221 tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock);
222 tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent",
223 sizeof(struct tmpfs_dirent),
224 NULL, NULL, NULL, NULL,
225 UMA_ALIGN_PTR, 0);
226 tmp->tm_node_pool = uma_zcreate("TMPFS node",
227 sizeof(struct tmpfs_node),
228 tmpfs_node_ctor, tmpfs_node_dtor,
229 tmpfs_node_init, tmpfs_node_fini,
230 UMA_ALIGN_PTR, 0);
231
232 /* Allocate the root node. */
233 error = tmpfs_alloc_node(tmp, VDIR, root_uid,
234 root_gid, root_mode & ALLPERMS, NULL, NULL,
235 VNOVAL, &root);
236
237 if (error != 0 || root == NULL) {
238 uma_zdestroy(tmp->tm_node_pool);
239 uma_zdestroy(tmp->tm_dirent_pool);
240 delete_unrhdr(tmp->tm_ino_unr);
241 free(tmp, M_TMPFSMNT);
242 return error;
243 }
244 KASSERT(root->tn_id == 2, ("tmpfs root with invalid ino: %d", root->tn_id));
245 tmp->tm_root = root;
246
247 MNT_ILOCK(mp);
248 mp->mnt_flag |= MNT_LOCAL;
249 mp->mnt_kern_flag |= MNTK_MPSAFE;
250 MNT_IUNLOCK(mp);
251
252 mp->mnt_data = tmp;
253 mp->mnt_stat.f_namemax = MAXNAMLEN;
254 vfs_getnewfsid(mp);
255 vfs_mountedfrom(mp, "tmpfs");
256
257 return 0;
258 }
259
260 /* --------------------------------------------------------------------- */
261
262 /* ARGSUSED2 */
263 static int
264 tmpfs_unmount(struct mount *mp, int mntflags)
265 {
266 int error;
267 int flags = 0;
268 struct tmpfs_mount *tmp;
269 struct tmpfs_node *node;
270
271 /* Handle forced unmounts. */
272 if (mntflags & MNT_FORCE)
273 flags |= FORCECLOSE;
274
275 /* Finalize all pending I/O. */
276 error = vflush(mp, 0, flags, curthread);
277 if (error != 0)
278 return error;
279
280 tmp = VFS_TO_TMPFS(mp);
281
282 /* Free all associated data. The loop iterates over the linked list
283 * we have containing all used nodes. For each of them that is
284 * a directory, we free all its directory entries. Note that after
285 * freeing a node, it will automatically go to the available list,
286 * so we will later have to iterate over it to release its items. */
287 node = LIST_FIRST(&tmp->tm_nodes_used);
288 while (node != NULL) {
289 struct tmpfs_node *next;
290
291 if (node->tn_type == VDIR) {
292 struct tmpfs_dirent *de;
293
294 de = TAILQ_FIRST(&node->tn_dir.tn_dirhead);
295 while (de != NULL) {
296 struct tmpfs_dirent *nde;
297
298 nde = TAILQ_NEXT(de, td_entries);
299 tmpfs_free_dirent(tmp, de, FALSE);
300 de = nde;
301 node->tn_size -= sizeof(struct tmpfs_dirent);
302 }
303 }
304
305 next = LIST_NEXT(node, tn_entries);
306 tmpfs_free_node(tmp, node);
307 node = next;
308 }
309
310 uma_zdestroy(tmp->tm_dirent_pool);
311 uma_zdestroy(tmp->tm_node_pool);
312 delete_unrhdr(tmp->tm_ino_unr);
313
314 mtx_destroy(&tmp->allnode_lock);
315 MPASS(tmp->tm_pages_used == 0);
316 MPASS(tmp->tm_nodes_inuse == 0);
317
318 /* Throw away the tmpfs_mount structure. */
319 free(mp->mnt_data, M_TMPFSMNT);
320 mp->mnt_data = NULL;
321
322 MNT_ILOCK(mp);
323 mp->mnt_flag &= ~MNT_LOCAL;
324 MNT_IUNLOCK(mp);
325 return 0;
326 }
327
328 /* --------------------------------------------------------------------- */
329
330 static int
331 tmpfs_root(struct mount *mp, int flags, struct vnode **vpp)
332 {
333 int error;
334 error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp);
335
336 if (!error)
337 (*vpp)->v_vflag |= VV_ROOT;
338
339 return error;
340 }
341
342 /* --------------------------------------------------------------------- */
343
344 static int
345 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, int flags,
346 struct vnode **vpp)
347 {
348 boolean_t found;
349 struct tmpfs_fid *tfhp;
350 struct tmpfs_mount *tmp;
351 struct tmpfs_node *node;
352
353 tmp = VFS_TO_TMPFS(mp);
354
355 tfhp = (struct tmpfs_fid *)fhp;
356 if (tfhp->tf_len != sizeof(struct tmpfs_fid))
357 return EINVAL;
358
359 if (tfhp->tf_id >= tmp->tm_nodes_max)
360 return EINVAL;
361
362 found = FALSE;
363
364 TMPFS_LOCK(tmp);
365 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
366 if (node->tn_id == tfhp->tf_id &&
367 node->tn_gen == tfhp->tf_gen) {
368 found = TRUE;
369 break;
370 }
371 }
372 TMPFS_UNLOCK(tmp);
373
374 if (found)
375 return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp));
376
377 return (EINVAL);
378 }
379
380 /* --------------------------------------------------------------------- */
381
382 /* ARGSUSED2 */
383 static int
384 tmpfs_statfs(struct mount *mp, struct statfs *sbp)
385 {
386 fsfilcnt_t freenodes;
387 struct tmpfs_mount *tmp;
388
389 tmp = VFS_TO_TMPFS(mp);
390
391 sbp->f_iosize = PAGE_SIZE;
392 sbp->f_bsize = PAGE_SIZE;
393
394 sbp->f_blocks = TMPFS_PAGES_MAX(tmp);
395 sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp);
396
397 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_inuse,
398 TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node));
399
400 sbp->f_files = freenodes + tmp->tm_nodes_inuse;
401 sbp->f_ffree = freenodes;
402 /* sbp->f_owner = tmp->tn_uid; */
403
404 return 0;
405 }
406
407 /* --------------------------------------------------------------------- */
408
409 /*
410 * tmpfs vfs operations.
411 */
412
413 struct vfsops tmpfs_vfsops = {
414 .vfs_mount = tmpfs_mount,
415 .vfs_unmount = tmpfs_unmount,
416 .vfs_root = tmpfs_root,
417 .vfs_statfs = tmpfs_statfs,
418 .vfs_fhtovp = tmpfs_fhtovp,
419 };
420 VFS_SET(tmpfs_vfsops, tmpfs, 0);
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