1 /* $OpenBSD: tmpfs_vfsops.c,v 1.19 2021/10/24 15:41:47 patrick Exp $ */
2 /* $NetBSD: tmpfs_vfsops.c,v 1.52 2011/09/27 01:10:43 christos Exp $ */
3
4 /*
5 * Copyright (c) 2005, 2006, 2007 The NetBSD Foundation, Inc.
6 * All rights reserved.
7 *
8 * This code is derived from software contributed to The NetBSD Foundation
9 * by Julio M. Merino Vidal, developed as part of Google's Summer of Code
10 * 2005 program.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
23 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
25 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
32 */
33
34 /*
35 * Efficient memory file system.
36 *
37 * tmpfs is a file system that uses NetBSD's virtual memory sub-system
38 * (the well-known UVM) to store file data and metadata in an efficient
39 * way. This means that it does not follow the structure of an on-disk
40 * file system because it simply does not need to. Instead, it uses
41 * memory-specific data structures and algorithms to automatically
42 * allocate and release resources.
43 */
44
45 #include <sys/param.h>
46 #include <sys/mount.h>
47 #include <sys/stat.h>
48 #include <sys/systm.h>
49 #include <sys/vnode.h>
50 #include <sys/malloc.h>
51
52 #include <tmpfs/tmpfs.h>
53
54 /* MODULE(MODULE_CLASS_VFS, tmpfs, NULL); */
55
56 struct pool tmpfs_dirent_pool;
57 struct pool tmpfs_node_pool;
58
59 int tmpfs_mount(struct mount *, const char *, void *, struct nameidata *,
60 struct proc *);
61 int tmpfs_start(struct mount *, int, struct proc *);
62 int tmpfs_unmount(struct mount *, int, struct proc *);
63 int tmpfs_root(struct mount *, struct vnode **);
64 int tmpfs_vget(struct mount *, ino_t, struct vnode **);
65 int tmpfs_fhtovp(struct mount *, struct fid *, struct vnode **);
66 int tmpfs_vptofh(struct vnode *, struct fid *);
67 int tmpfs_statfs(struct mount *, struct statfs *, struct proc *);
68 int tmpfs_sync(struct mount *, int, int, struct ucred *, struct proc *);
69 int tmpfs_init(struct vfsconf *);
70 int tmpfs_mount_update(struct mount *);
71
72 int
tmpfs_init(struct vfsconf * vfsp)73 tmpfs_init(struct vfsconf *vfsp)
74 {
75
76 pool_init(&tmpfs_dirent_pool, sizeof(tmpfs_dirent_t), 0, IPL_NONE,
77 PR_WAITOK, "tmpfs_dirent", NULL);
78 pool_init(&tmpfs_node_pool, sizeof(tmpfs_node_t), 0, IPL_NONE,
79 PR_WAITOK, "tmpfs_node", NULL);
80
81 return 0;
82 }
83
84 int
tmpfs_mount_update(struct mount * mp)85 tmpfs_mount_update(struct mount *mp)
86 {
87 tmpfs_mount_t *tmp;
88 struct vnode *rootvp;
89 int error;
90
91 if ((mp->mnt_flag & MNT_RDONLY) == 0)
92 return EOPNOTSUPP;
93
94 /* ro->rw transition: nothing to do? */
95 if (mp->mnt_flag & MNT_WANTRDWR)
96 return 0;
97
98 tmp = mp->mnt_data;
99 rootvp = tmp->tm_root->tn_vnode;
100
101 /* Lock root to prevent lookups. */
102 error = vn_lock(rootvp, LK_EXCLUSIVE | LK_RETRY);
103 if (error)
104 return error;
105
106 /* Lock mount point to prevent nodes from being added/removed. */
107 rw_enter_write(&tmp->tm_lock);
108
109 /* Flush files opened for writing; skip rootvp. */
110 error = vflush(mp, rootvp, WRITECLOSE);
111
112 rw_exit_write(&tmp->tm_lock);
113 VOP_UNLOCK(rootvp);
114
115 return error;
116 }
117
118 int
tmpfs_mount(struct mount * mp,const char * path,void * data,struct nameidata * ndp,struct proc * p)119 tmpfs_mount(struct mount *mp, const char *path, void *data,
120 struct nameidata *ndp, struct proc *p)
121 {
122 struct tmpfs_args *args = data;
123 tmpfs_mount_t *tmp;
124 tmpfs_node_t *root;
125 uint64_t memlimit;
126 uint64_t nodes;
127 int error;
128
129 if (mp->mnt_flag & MNT_UPDATE)
130 return (tmpfs_mount_update(mp));
131
132 /* Prohibit mounts if there is not enough memory. */
133 if (tmpfs_mem_info(1) < TMPFS_PAGES_RESERVED)
134 return EINVAL;
135
136 if (args->ta_root_uid == VNOVAL || args->ta_root_gid == VNOVAL ||
137 args->ta_root_mode == VNOVAL)
138 return EINVAL;
139
140 /* Get the memory usage limit for this file-system. */
141 if (args->ta_size_max < PAGE_SIZE) {
142 memlimit = UINT64_MAX;
143 } else {
144 memlimit = args->ta_size_max;
145 }
146 KASSERT(memlimit > 0);
147
148 if (args->ta_nodes_max <= 3) {
149 nodes = 3 + (memlimit / 1024);
150 } else {
151 nodes = args->ta_nodes_max;
152 }
153 nodes = MIN(nodes, INT_MAX);
154 KASSERT(nodes >= 3);
155
156 /* Allocate the tmpfs mount structure and fill it. */
157 tmp = malloc(sizeof(tmpfs_mount_t), M_MISCFSMNT, M_WAITOK);
158
159 tmp->tm_nodes_max = (ino_t)nodes;
160 tmp->tm_nodes_cnt = 0;
161 tmp->tm_highest_inode = 1;
162 LIST_INIT(&tmp->tm_nodes);
163
164 rw_init(&tmp->tm_lock, "tmplk");
165 tmpfs_mntmem_init(tmp, memlimit);
166
167 /* Allocate the root node. */
168 error = tmpfs_alloc_node(tmp, VDIR, args->ta_root_uid,
169 args->ta_root_gid, args->ta_root_mode & ALLPERMS, NULL,
170 VNOVAL, &root);
171 KASSERT(error == 0 && root != NULL);
172
173 /*
174 * Parent of the root inode is itself. Also, root inode has no
175 * directory entry (i.e. is never attached), thus hold an extra
176 * reference (link) for it.
177 */
178 root->tn_links++;
179 root->tn_spec.tn_dir.tn_parent = root;
180 tmp->tm_root = root;
181
182 mp->mnt_data = tmp;
183 mp->mnt_flag |= MNT_LOCAL;
184 mp->mnt_stat.f_namemax = TMPFS_MAXNAMLEN;
185 vfs_getnewfsid(mp);
186
187 mp->mnt_stat.mount_info.tmpfs_args = *args;
188
189 bzero(&mp->mnt_stat.f_mntonname, sizeof(mp->mnt_stat.f_mntonname));
190 bzero(&mp->mnt_stat.f_mntfromname, sizeof(mp->mnt_stat.f_mntfromname));
191 bzero(&mp->mnt_stat.f_mntfromspec, sizeof(mp->mnt_stat.f_mntfromspec));
192
193 strlcpy(mp->mnt_stat.f_mntonname, path,
194 sizeof(mp->mnt_stat.f_mntonname) - 1);
195 strlcpy(mp->mnt_stat.f_mntfromname, "tmpfs",
196 sizeof(mp->mnt_stat.f_mntfromname) - 1);
197 strlcpy(mp->mnt_stat.f_mntfromspec, "tmpfs",
198 sizeof(mp->mnt_stat.f_mntfromspec) - 1);
199
200 return error;
201 }
202
203 int
tmpfs_start(struct mount * mp,int flags,struct proc * p)204 tmpfs_start(struct mount *mp, int flags, struct proc *p)
205 {
206 return 0;
207 }
208
209 int
tmpfs_unmount(struct mount * mp,int mntflags,struct proc * p)210 tmpfs_unmount(struct mount *mp, int mntflags, struct proc *p)
211 {
212 tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp);
213 tmpfs_node_t *node, *cnode;
214 int error, flags = 0;
215
216 /* Handle forced unmounts. */
217 if (mntflags & MNT_FORCE)
218 flags |= FORCECLOSE;
219
220 /* Finalize all pending I/O. */
221 error = vflush(mp, NULL, flags);
222 if (error != 0)
223 return error;
224
225 /*
226 * First round, detach and destroy all directory entries.
227 * Also, clear the pointers to the vnodes - they are gone.
228 */
229 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) {
230 tmpfs_dirent_t *de;
231
232 node->tn_vnode = NULL;
233 if (node->tn_type != VDIR) {
234 continue;
235 }
236 while ((de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir)) != NULL) {
237 cnode = de->td_node;
238 if (cnode)
239 cnode->tn_vnode = NULL;
240 tmpfs_dir_detach(node, de);
241 tmpfs_free_dirent(tmp, de);
242 }
243 }
244
245 /* Second round, destroy all inodes. */
246 while ((node = LIST_FIRST(&tmp->tm_nodes)) != NULL) {
247 tmpfs_free_node(tmp, node);
248 }
249
250 /* Throw away the tmpfs_mount structure. */
251 tmpfs_mntmem_destroy(tmp);
252 /* mutex_destroy(&tmp->tm_lock); */
253 /* kmem_free(tmp, sizeof(*tmp)); */
254 free(tmp, M_MISCFSMNT, sizeof(tmpfs_mount_t));
255 mp->mnt_data = NULL;
256
257 return 0;
258 }
259
260 int
tmpfs_root(struct mount * mp,struct vnode ** vpp)261 tmpfs_root(struct mount *mp, struct vnode **vpp)
262 {
263 tmpfs_node_t *node = VFS_TO_TMPFS(mp)->tm_root;
264
265 rw_enter_write(&node->tn_nlock);
266 return tmpfs_vnode_get(mp, node, vpp);
267 }
268
269 int
tmpfs_vget(struct mount * mp,ino_t ino,struct vnode ** vpp)270 tmpfs_vget(struct mount *mp, ino_t ino, struct vnode **vpp)
271 {
272
273 printf("tmpfs_vget called; need for it unknown yet\n");
274 return EOPNOTSUPP;
275 }
276
277 int
tmpfs_fhtovp(struct mount * mp,struct fid * fhp,struct vnode ** vpp)278 tmpfs_fhtovp(struct mount *mp, struct fid *fhp, struct vnode **vpp)
279 {
280 tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp);
281 tmpfs_node_t *node;
282 tmpfs_fid_t tfh;
283
284 if (fhp->fid_len != sizeof(tmpfs_fid_t)) {
285 return EINVAL;
286 }
287 memcpy(&tfh, fhp, sizeof(tmpfs_fid_t));
288
289 rw_enter_write(&tmp->tm_lock);
290 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) {
291 if (node->tn_id != tfh.tf_id) {
292 continue;
293 }
294 if (TMPFS_NODE_GEN(node) != tfh.tf_gen) {
295 continue;
296 }
297 rw_enter_write(&node->tn_nlock);
298 break;
299 }
300 rw_exit_write(&tmp->tm_lock);
301
302 /* Will release the tn_nlock. */
303 return node ? tmpfs_vnode_get(mp, node, vpp) : ESTALE;
304 }
305
306 int
tmpfs_vptofh(struct vnode * vp,struct fid * fhp)307 tmpfs_vptofh(struct vnode *vp, struct fid *fhp)
308 {
309 tmpfs_fid_t tfh;
310 tmpfs_node_t *node;
311
312 node = VP_TO_TMPFS_NODE(vp);
313
314 memset(&tfh, 0, sizeof(tfh));
315 tfh.tf_len = sizeof(tmpfs_fid_t);
316 tfh.tf_gen = TMPFS_NODE_GEN(node);
317 tfh.tf_id = node->tn_id;
318 memcpy(fhp, &tfh, sizeof(tfh));
319
320 return 0;
321 }
322
323 int
tmpfs_statfs(struct mount * mp,struct statfs * sbp,struct proc * p)324 tmpfs_statfs(struct mount *mp, struct statfs *sbp, struct proc *p)
325 {
326 tmpfs_mount_t *tmp;
327 fsfilcnt_t freenodes;
328 uint64_t avail;
329
330 tmp = VFS_TO_TMPFS(mp);
331
332 sbp->f_iosize = sbp->f_bsize = PAGE_SIZE;
333
334 rw_enter_write(&tmp->tm_acc_lock);
335 avail = tmpfs_pages_avail(tmp);
336 sbp->f_blocks = (tmpfs_bytes_max(tmp) >> PAGE_SHIFT);
337 sbp->f_bfree = avail;
338 sbp->f_bavail = avail & INT64_MAX; /* f_bavail is int64_t */
339
340 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_cnt,
341 avail * PAGE_SIZE / sizeof(tmpfs_node_t));
342
343 sbp->f_files = tmp->tm_nodes_cnt + freenodes;
344 sbp->f_ffree = freenodes;
345 sbp->f_favail = freenodes & INT64_MAX; /* f_favail is int64_t */
346 rw_exit_write(&tmp->tm_acc_lock);
347
348 copy_statfs_info(sbp, mp);
349
350 return 0;
351 }
352
353 int
tmpfs_sync(struct mount * mp,int waitfor,int stall,struct ucred * cred,struct proc * p)354 tmpfs_sync(struct mount *mp, int waitfor, int stall, struct ucred *cred,
355 struct proc *p)
356 {
357
358 return 0;
359 }
360
361 /*
362 * tmpfs vfs operations.
363 */
364
365 const struct vfsops tmpfs_vfsops = {
366 .vfs_mount = tmpfs_mount,
367 .vfs_start = tmpfs_start,
368 .vfs_unmount = tmpfs_unmount,
369 .vfs_root = tmpfs_root,
370 .vfs_quotactl = (void *)eopnotsupp,
371 .vfs_statfs = tmpfs_statfs,
372 .vfs_sync = tmpfs_sync,
373 .vfs_vget = tmpfs_vget,
374 .vfs_fhtovp = tmpfs_fhtovp,
375 .vfs_vptofh = tmpfs_vptofh,
376 .vfs_init = tmpfs_init,
377 .vfs_sysctl = (void *)eopnotsupp,
378 .vfs_checkexp = (void *)eopnotsupp,
379 };
380