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/8.4/sys/fs/tmpfs/tmpfs_vfsops.c 234512 2012-04-20 22:16:08Z rmh $");
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 *, struct vnode **);
75 static int tmpfs_statfs(struct mount *, struct statfs *);
76
77 /* --------------------------------------------------------------------- */
78
79 static const char *tmpfs_opts[] = {
80 "from", "size", "maxfilesize", "inodes", "uid", "gid", "mode", "export",
81 NULL
82 };
83
84 /* --------------------------------------------------------------------- */
85
86 static int
87 tmpfs_node_ctor(void *mem, int size, void *arg, int flags)
88 {
89 struct tmpfs_node *node = (struct tmpfs_node *)mem;
90
91 node->tn_gen++;
92 node->tn_size = 0;
93 node->tn_status = 0;
94 node->tn_flags = 0;
95 node->tn_links = 0;
96 node->tn_vnode = NULL;
97 node->tn_vpstate = 0;
98
99 return (0);
100 }
101
102 static void
103 tmpfs_node_dtor(void *mem, int size, void *arg)
104 {
105 struct tmpfs_node *node = (struct tmpfs_node *)mem;
106 node->tn_type = VNON;
107 }
108
109 static int
110 tmpfs_node_init(void *mem, int size, int flags)
111 {
112 struct tmpfs_node *node = (struct tmpfs_node *)mem;
113 node->tn_id = 0;
114
115 mtx_init(&node->tn_interlock, "tmpfs node interlock", NULL, MTX_DEF);
116 node->tn_gen = arc4random();
117
118 return (0);
119 }
120
121 static void
122 tmpfs_node_fini(void *mem, int size)
123 {
124 struct tmpfs_node *node = (struct tmpfs_node *)mem;
125
126 mtx_destroy(&node->tn_interlock);
127 }
128
129 static int
130 tmpfs_mount(struct mount *mp)
131 {
132 struct tmpfs_mount *tmp;
133 struct tmpfs_node *root;
134 size_t pages;
135 uint32_t nodes;
136 int error;
137 /* Size counters. */
138 u_int nodes_max;
139 u_quad_t size_max, maxfilesize;
140
141 /* Root node attributes. */
142 uid_t root_uid;
143 gid_t root_gid;
144 mode_t root_mode;
145
146 struct vattr va;
147
148 if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts))
149 return (EINVAL);
150
151 if (mp->mnt_flag & MNT_UPDATE) {
152 /* XXX: There is no support yet to update file system
153 * settings. Should be added. */
154
155 return EOPNOTSUPP;
156 }
157
158 vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
159 error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred);
160 VOP_UNLOCK(mp->mnt_vnodecovered, 0);
161 if (error)
162 return (error);
163
164 if (mp->mnt_cred->cr_ruid != 0 ||
165 vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1)
166 root_gid = va.va_gid;
167 if (mp->mnt_cred->cr_ruid != 0 ||
168 vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1)
169 root_uid = va.va_uid;
170 if (mp->mnt_cred->cr_ruid != 0 ||
171 vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1)
172 root_mode = va.va_mode;
173 if (vfs_scanopt(mp->mnt_optnew, "inodes", "%u", &nodes_max) != 1)
174 nodes_max = 0;
175 if (vfs_scanopt(mp->mnt_optnew, "size", "%qu", &size_max) != 1)
176 size_max = 0;
177 if (vfs_scanopt(mp->mnt_optnew, "maxfilesize", "%qu",
178 &maxfilesize) != 1)
179 maxfilesize = 0;
180
181 /* Do not allow mounts if we do not have enough memory to preserve
182 * the minimum reserved pages. */
183 if (tmpfs_mem_info() < TMPFS_PAGES_RESERVED)
184 return ENOSPC;
185
186 /* Get the maximum number of memory pages this file system is
187 * allowed to use, based on the maximum size the user passed in
188 * the mount structure. A value of zero is treated as if the
189 * maximum available space was requested. */
190 if (size_max < PAGE_SIZE || size_max > SIZE_MAX - PAGE_SIZE)
191 pages = SIZE_MAX;
192 else
193 pages = howmany(size_max, PAGE_SIZE);
194 MPASS(pages > 0);
195
196 if (nodes_max <= 3) {
197 if (pages > UINT32_MAX - 3)
198 nodes = UINT32_MAX;
199 else
200 nodes = pages + 3;
201 } else
202 nodes = nodes_max;
203 MPASS(nodes >= 3);
204
205 /* Allocate the tmpfs mount structure and fill it. */
206 tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount),
207 M_TMPFSMNT, M_WAITOK | M_ZERO);
208
209 mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF);
210 tmp->tm_nodes_max = nodes;
211 tmp->tm_nodes_inuse = 0;
212 tmp->tm_maxfilesize = maxfilesize > 0 ? maxfilesize : UINT64_MAX;
213 LIST_INIT(&tmp->tm_nodes_used);
214
215 tmp->tm_pages_max = pages;
216 tmp->tm_pages_used = 0;
217 tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock);
218 tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent",
219 sizeof(struct tmpfs_dirent),
220 NULL, NULL, NULL, NULL,
221 UMA_ALIGN_PTR, 0);
222 tmp->tm_node_pool = uma_zcreate("TMPFS node",
223 sizeof(struct tmpfs_node),
224 tmpfs_node_ctor, tmpfs_node_dtor,
225 tmpfs_node_init, tmpfs_node_fini,
226 UMA_ALIGN_PTR, 0);
227
228 /* Allocate the root node. */
229 error = tmpfs_alloc_node(tmp, VDIR, root_uid,
230 root_gid, root_mode & ALLPERMS, NULL, NULL,
231 VNOVAL, &root);
232
233 if (error != 0 || root == NULL) {
234 uma_zdestroy(tmp->tm_node_pool);
235 uma_zdestroy(tmp->tm_dirent_pool);
236 delete_unrhdr(tmp->tm_ino_unr);
237 free(tmp, M_TMPFSMNT);
238 return error;
239 }
240 KASSERT(root->tn_id == 2, ("tmpfs root with invalid ino: %d", root->tn_id));
241 tmp->tm_root = root;
242
243 MNT_ILOCK(mp);
244 mp->mnt_flag |= MNT_LOCAL;
245 mp->mnt_kern_flag |= MNTK_MPSAFE;
246 MNT_IUNLOCK(mp);
247
248 mp->mnt_data = tmp;
249 mp->mnt_stat.f_namemax = MAXNAMLEN;
250 vfs_getnewfsid(mp);
251 vfs_mountedfrom(mp, "tmpfs");
252
253 return 0;
254 }
255
256 /* --------------------------------------------------------------------- */
257
258 /* ARGSUSED2 */
259 static int
260 tmpfs_unmount(struct mount *mp, int mntflags)
261 {
262 int error;
263 int flags = 0;
264 struct tmpfs_mount *tmp;
265 struct tmpfs_node *node;
266
267 /* Handle forced unmounts. */
268 if (mntflags & MNT_FORCE)
269 flags |= FORCECLOSE;
270
271 /* Finalize all pending I/O. */
272 error = vflush(mp, 0, flags, curthread);
273 if (error != 0)
274 return error;
275
276 tmp = VFS_TO_TMPFS(mp);
277
278 /* Free all associated data. The loop iterates over the linked list
279 * we have containing all used nodes. For each of them that is
280 * a directory, we free all its directory entries. Note that after
281 * freeing a node, it will automatically go to the available list,
282 * so we will later have to iterate over it to release its items. */
283 node = LIST_FIRST(&tmp->tm_nodes_used);
284 while (node != NULL) {
285 struct tmpfs_node *next;
286
287 if (node->tn_type == VDIR) {
288 struct tmpfs_dirent *de;
289
290 de = TAILQ_FIRST(&node->tn_dir.tn_dirhead);
291 while (de != NULL) {
292 struct tmpfs_dirent *nde;
293
294 nde = TAILQ_NEXT(de, td_entries);
295 tmpfs_free_dirent(tmp, de, FALSE);
296 de = nde;
297 node->tn_size -= sizeof(struct tmpfs_dirent);
298 }
299 }
300
301 next = LIST_NEXT(node, tn_entries);
302 tmpfs_free_node(tmp, node);
303 node = next;
304 }
305
306 uma_zdestroy(tmp->tm_dirent_pool);
307 uma_zdestroy(tmp->tm_node_pool);
308 delete_unrhdr(tmp->tm_ino_unr);
309
310 mtx_destroy(&tmp->allnode_lock);
311 MPASS(tmp->tm_pages_used == 0);
312 MPASS(tmp->tm_nodes_inuse == 0);
313
314 /* Throw away the tmpfs_mount structure. */
315 free(mp->mnt_data, M_TMPFSMNT);
316 mp->mnt_data = NULL;
317
318 MNT_ILOCK(mp);
319 mp->mnt_flag &= ~MNT_LOCAL;
320 MNT_IUNLOCK(mp);
321 return 0;
322 }
323
324 /* --------------------------------------------------------------------- */
325
326 static int
327 tmpfs_root(struct mount *mp, int flags, struct vnode **vpp)
328 {
329 int error;
330 error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp);
331
332 if (!error)
333 (*vpp)->v_vflag |= VV_ROOT;
334
335 return error;
336 }
337
338 /* --------------------------------------------------------------------- */
339
340 static int
341 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
342 {
343 boolean_t found;
344 struct tmpfs_fid *tfhp;
345 struct tmpfs_mount *tmp;
346 struct tmpfs_node *node;
347
348 tmp = VFS_TO_TMPFS(mp);
349
350 tfhp = (struct tmpfs_fid *)fhp;
351 if (tfhp->tf_len != sizeof(struct tmpfs_fid))
352 return EINVAL;
353
354 if (tfhp->tf_id >= tmp->tm_nodes_max)
355 return EINVAL;
356
357 found = FALSE;
358
359 TMPFS_LOCK(tmp);
360 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
361 if (node->tn_id == tfhp->tf_id &&
362 node->tn_gen == tfhp->tf_gen) {
363 found = TRUE;
364 break;
365 }
366 }
367 TMPFS_UNLOCK(tmp);
368
369 if (found)
370 return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp));
371
372 return (EINVAL);
373 }
374
375 /* --------------------------------------------------------------------- */
376
377 /* ARGSUSED2 */
378 static int
379 tmpfs_statfs(struct mount *mp, struct statfs *sbp)
380 {
381 fsfilcnt_t freenodes;
382 struct tmpfs_mount *tmp;
383
384 tmp = VFS_TO_TMPFS(mp);
385
386 sbp->f_iosize = PAGE_SIZE;
387 sbp->f_bsize = PAGE_SIZE;
388
389 sbp->f_blocks = TMPFS_PAGES_MAX(tmp);
390 sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp);
391
392 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_inuse,
393 TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node));
394
395 sbp->f_files = freenodes + tmp->tm_nodes_inuse;
396 sbp->f_ffree = freenodes;
397 /* sbp->f_owner = tmp->tn_uid; */
398
399 return 0;
400 }
401
402 /* --------------------------------------------------------------------- */
403
404 /*
405 * tmpfs vfs operations.
406 */
407
408 struct vfsops tmpfs_vfsops = {
409 .vfs_mount = tmpfs_mount,
410 .vfs_unmount = tmpfs_unmount,
411 .vfs_root = tmpfs_root,
412 .vfs_statfs = tmpfs_statfs,
413 .vfs_fhtovp = tmpfs_fhtovp,
414 };
415 VFS_SET(tmpfs_vfsops, tmpfs, 0);
Cache object: 7969609765387ca0ed96a8644c2f2984
|