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("$FreeBSD$");
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 static const char *tmpfs_updateopts[] = {
85 "from", "export", NULL
86 };
87
88 /* --------------------------------------------------------------------- */
89
90 static int
91 tmpfs_node_ctor(void *mem, int size, void *arg, int flags)
92 {
93 struct tmpfs_node *node = (struct tmpfs_node *)mem;
94
95 node->tn_gen++;
96 node->tn_size = 0;
97 node->tn_status = 0;
98 node->tn_flags = 0;
99 node->tn_links = 0;
100 node->tn_vnode = NULL;
101 node->tn_vpstate = 0;
102
103 return (0);
104 }
105
106 static void
107 tmpfs_node_dtor(void *mem, int size, void *arg)
108 {
109 struct tmpfs_node *node = (struct tmpfs_node *)mem;
110 node->tn_type = VNON;
111 }
112
113 static int
114 tmpfs_node_init(void *mem, int size, int flags)
115 {
116 struct tmpfs_node *node = (struct tmpfs_node *)mem;
117 node->tn_id = 0;
118
119 mtx_init(&node->tn_interlock, "tmpfs node interlock", NULL, MTX_DEF);
120 node->tn_gen = arc4random();
121
122 return (0);
123 }
124
125 static void
126 tmpfs_node_fini(void *mem, int size)
127 {
128 struct tmpfs_node *node = (struct tmpfs_node *)mem;
129
130 mtx_destroy(&node->tn_interlock);
131 }
132
133 static int
134 tmpfs_mount(struct mount *mp)
135 {
136 struct tmpfs_mount *tmp;
137 struct tmpfs_node *root;
138 size_t pages;
139 uint32_t nodes;
140 int error;
141 /* Size counters. */
142 u_int nodes_max;
143 u_quad_t size_max, maxfilesize;
144
145 /* Root node attributes. */
146 uid_t root_uid;
147 gid_t root_gid;
148 mode_t root_mode;
149
150 struct vattr va;
151
152 if (vfs_filteropt(mp->mnt_optnew, tmpfs_opts))
153 return (EINVAL);
154
155 if (mp->mnt_flag & MNT_UPDATE) {
156 /* Only support update mounts for certain options. */
157 if (vfs_filteropt(mp->mnt_optnew, tmpfs_updateopts) != 0)
158 return (EOPNOTSUPP);
159 if (vfs_flagopt(mp->mnt_optnew, "ro", NULL, 0) !=
160 ((struct tmpfs_mount *)mp->mnt_data)->tm_ronly)
161 return (EOPNOTSUPP);
162 return (0);
163 }
164
165 vn_lock(mp->mnt_vnodecovered, LK_SHARED | LK_RETRY);
166 error = VOP_GETATTR(mp->mnt_vnodecovered, &va, mp->mnt_cred);
167 VOP_UNLOCK(mp->mnt_vnodecovered, 0);
168 if (error)
169 return (error);
170
171 if (mp->mnt_cred->cr_ruid != 0 ||
172 vfs_scanopt(mp->mnt_optnew, "gid", "%d", &root_gid) != 1)
173 root_gid = va.va_gid;
174 if (mp->mnt_cred->cr_ruid != 0 ||
175 vfs_scanopt(mp->mnt_optnew, "uid", "%d", &root_uid) != 1)
176 root_uid = va.va_uid;
177 if (mp->mnt_cred->cr_ruid != 0 ||
178 vfs_scanopt(mp->mnt_optnew, "mode", "%ho", &root_mode) != 1)
179 root_mode = va.va_mode;
180 if (vfs_scanopt(mp->mnt_optnew, "inodes", "%u", &nodes_max) != 1)
181 nodes_max = 0;
182 if (vfs_scanopt(mp->mnt_optnew, "size", "%qu", &size_max) != 1)
183 size_max = 0;
184 if (vfs_scanopt(mp->mnt_optnew, "maxfilesize", "%qu",
185 &maxfilesize) != 1)
186 maxfilesize = 0;
187
188 /* Do not allow mounts if we do not have enough memory to preserve
189 * the minimum reserved pages. */
190 if (tmpfs_mem_info() < TMPFS_PAGES_RESERVED)
191 return ENOSPC;
192
193 /* Get the maximum number of memory pages this file system is
194 * allowed to use, based on the maximum size the user passed in
195 * the mount structure. A value of zero is treated as if the
196 * maximum available space was requested. */
197 if (size_max < PAGE_SIZE || size_max > SIZE_MAX - PAGE_SIZE)
198 pages = SIZE_MAX;
199 else
200 pages = howmany(size_max, PAGE_SIZE);
201 MPASS(pages > 0);
202
203 if (nodes_max <= 3) {
204 if (pages > UINT32_MAX - 3)
205 nodes = UINT32_MAX;
206 else
207 nodes = pages + 3;
208 } else
209 nodes = nodes_max;
210 MPASS(nodes >= 3);
211
212 /* Allocate the tmpfs mount structure and fill it. */
213 tmp = (struct tmpfs_mount *)malloc(sizeof(struct tmpfs_mount),
214 M_TMPFSMNT, M_WAITOK | M_ZERO);
215
216 mtx_init(&tmp->allnode_lock, "tmpfs allnode lock", NULL, MTX_DEF);
217 tmp->tm_nodes_max = nodes;
218 tmp->tm_nodes_inuse = 0;
219 tmp->tm_maxfilesize = maxfilesize > 0 ? maxfilesize : UINT64_MAX;
220 LIST_INIT(&tmp->tm_nodes_used);
221
222 tmp->tm_pages_max = pages;
223 tmp->tm_pages_used = 0;
224 tmp->tm_ino_unr = new_unrhdr(2, INT_MAX, &tmp->allnode_lock);
225 tmp->tm_dirent_pool = uma_zcreate("TMPFS dirent",
226 sizeof(struct tmpfs_dirent),
227 NULL, NULL, NULL, NULL,
228 UMA_ALIGN_PTR, 0);
229 tmp->tm_node_pool = uma_zcreate("TMPFS node",
230 sizeof(struct tmpfs_node),
231 tmpfs_node_ctor, tmpfs_node_dtor,
232 tmpfs_node_init, tmpfs_node_fini,
233 UMA_ALIGN_PTR, 0);
234 tmp->tm_ronly = (mp->mnt_flag & MNT_RDONLY) != 0;
235
236 /* Allocate the root node. */
237 error = tmpfs_alloc_node(tmp, VDIR, root_uid,
238 root_gid, root_mode & ALLPERMS, NULL, NULL,
239 VNOVAL, &root);
240
241 if (error != 0 || root == NULL) {
242 uma_zdestroy(tmp->tm_node_pool);
243 uma_zdestroy(tmp->tm_dirent_pool);
244 delete_unrhdr(tmp->tm_ino_unr);
245 free(tmp, M_TMPFSMNT);
246 return error;
247 }
248 KASSERT(root->tn_id == 2, ("tmpfs root with invalid ino: %d", root->tn_id));
249 tmp->tm_root = root;
250
251 MNT_ILOCK(mp);
252 mp->mnt_flag |= MNT_LOCAL;
253 mp->mnt_kern_flag |= MNTK_MPSAFE;
254 MNT_IUNLOCK(mp);
255
256 mp->mnt_data = tmp;
257 mp->mnt_stat.f_namemax = MAXNAMLEN;
258 vfs_getnewfsid(mp);
259 vfs_mountedfrom(mp, "tmpfs");
260
261 return 0;
262 }
263
264 /* --------------------------------------------------------------------- */
265
266 /* ARGSUSED2 */
267 static int
268 tmpfs_unmount(struct mount *mp, int mntflags)
269 {
270 int error;
271 int flags = 0;
272 struct tmpfs_mount *tmp;
273 struct tmpfs_node *node;
274
275 /* Handle forced unmounts. */
276 if (mntflags & MNT_FORCE)
277 flags |= FORCECLOSE;
278
279 /* Finalize all pending I/O. */
280 error = vflush(mp, 0, flags, curthread);
281 if (error != 0)
282 return error;
283
284 tmp = VFS_TO_TMPFS(mp);
285
286 /* Free all associated data. The loop iterates over the linked list
287 * we have containing all used nodes. For each of them that is
288 * a directory, we free all its directory entries. Note that after
289 * freeing a node, it will automatically go to the available list,
290 * so we will later have to iterate over it to release its items. */
291 node = LIST_FIRST(&tmp->tm_nodes_used);
292 while (node != NULL) {
293 struct tmpfs_node *next;
294
295 if (node->tn_type == VDIR) {
296 struct tmpfs_dirent *de;
297
298 de = TAILQ_FIRST(&node->tn_dir.tn_dirhead);
299 while (de != NULL) {
300 struct tmpfs_dirent *nde;
301
302 nde = TAILQ_NEXT(de, td_entries);
303 tmpfs_free_dirent(tmp, de, FALSE);
304 de = nde;
305 node->tn_size -= sizeof(struct tmpfs_dirent);
306 }
307 }
308
309 next = LIST_NEXT(node, tn_entries);
310 tmpfs_free_node(tmp, node);
311 node = next;
312 }
313
314 uma_zdestroy(tmp->tm_dirent_pool);
315 uma_zdestroy(tmp->tm_node_pool);
316 delete_unrhdr(tmp->tm_ino_unr);
317
318 mtx_destroy(&tmp->allnode_lock);
319 MPASS(tmp->tm_pages_used == 0);
320 MPASS(tmp->tm_nodes_inuse == 0);
321
322 /* Throw away the tmpfs_mount structure. */
323 free(mp->mnt_data, M_TMPFSMNT);
324 mp->mnt_data = NULL;
325
326 MNT_ILOCK(mp);
327 mp->mnt_flag &= ~MNT_LOCAL;
328 MNT_IUNLOCK(mp);
329 return 0;
330 }
331
332 /* --------------------------------------------------------------------- */
333
334 static int
335 tmpfs_root(struct mount *mp, int flags, struct vnode **vpp)
336 {
337 int error;
338 error = tmpfs_alloc_vp(mp, VFS_TO_TMPFS(mp)->tm_root, flags, vpp);
339
340 if (!error)
341 (*vpp)->v_vflag |= VV_ROOT;
342
343 return error;
344 }
345
346 /* --------------------------------------------------------------------- */
347
348 static int
349 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
350 {
351 boolean_t found;
352 struct tmpfs_fid *tfhp;
353 struct tmpfs_mount *tmp;
354 struct tmpfs_node *node;
355
356 tmp = VFS_TO_TMPFS(mp);
357
358 tfhp = (struct tmpfs_fid *)fhp;
359 if (tfhp->tf_len != sizeof(struct tmpfs_fid))
360 return EINVAL;
361
362 if (tfhp->tf_id >= tmp->tm_nodes_max)
363 return EINVAL;
364
365 found = FALSE;
366
367 TMPFS_LOCK(tmp);
368 LIST_FOREACH(node, &tmp->tm_nodes_used, tn_entries) {
369 if (node->tn_id == tfhp->tf_id &&
370 node->tn_gen == tfhp->tf_gen) {
371 found = TRUE;
372 break;
373 }
374 }
375 TMPFS_UNLOCK(tmp);
376
377 if (found)
378 return (tmpfs_alloc_vp(mp, node, LK_EXCLUSIVE, vpp));
379
380 return (EINVAL);
381 }
382
383 /* --------------------------------------------------------------------- */
384
385 /* ARGSUSED2 */
386 static int
387 tmpfs_statfs(struct mount *mp, struct statfs *sbp)
388 {
389 fsfilcnt_t freenodes;
390 struct tmpfs_mount *tmp;
391
392 tmp = VFS_TO_TMPFS(mp);
393
394 sbp->f_iosize = PAGE_SIZE;
395 sbp->f_bsize = PAGE_SIZE;
396
397 sbp->f_blocks = TMPFS_PAGES_MAX(tmp);
398 sbp->f_bavail = sbp->f_bfree = TMPFS_PAGES_AVAIL(tmp);
399
400 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_inuse,
401 TMPFS_PAGES_AVAIL(tmp) * PAGE_SIZE / sizeof(struct tmpfs_node));
402
403 sbp->f_files = freenodes + tmp->tm_nodes_inuse;
404 sbp->f_ffree = freenodes;
405 /* sbp->f_owner = tmp->tn_uid; */
406
407 return 0;
408 }
409
410 /* --------------------------------------------------------------------- */
411
412 /*
413 * tmpfs vfs operations.
414 */
415
416 struct vfsops tmpfs_vfsops = {
417 .vfs_mount = tmpfs_mount,
418 .vfs_unmount = tmpfs_unmount,
419 .vfs_root = tmpfs_root,
420 .vfs_statfs = tmpfs_statfs,
421 .vfs_fhtovp = tmpfs_fhtovp,
422 };
423 VFS_SET(tmpfs_vfsops, tmpfs, 0);
Cache object: 44e7fdad63b933e03168bfd0498d47c3
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