1/* $NetBSD: tmpfs_vfsops.c,v 1.68 2016/08/26 21:44:24 dholland Exp $ */
2
3/*
4 * Copyright (c) 2005, 2006, 2007 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
44#include <sys/cdefs.h>
45__KERNEL_RCSID(0, "$NetBSD: tmpfs_vfsops.c,v 1.68 2016/08/26 21:44:24 dholland Exp $");
46
47#include <sys/param.h>
48#include <sys/atomic.h>
49#include <sys/types.h>
50#include <sys/kmem.h>
51#include <sys/mount.h>
52#include <sys/stat.h>
53#include <sys/systm.h>
54#include <sys/vnode.h>
55#include <sys/kauth.h>
56#include <sys/module.h>
57
58#include <miscfs/genfs/genfs.h>
59#include <fs/tmpfs/tmpfs.h>
60#include <fs/tmpfs/tmpfs_args.h>
61
62MODULE(MODULE_CLASS_VFS, tmpfs, NULL);
63
64struct pool tmpfs_dirent_pool;
65struct pool tmpfs_node_pool;
66
67void
68tmpfs_init(void)
69{
70
71 pool_init(&tmpfs_dirent_pool, sizeof(tmpfs_dirent_t), 0, 0, 0,
72 "tmpfs_dirent", &pool_allocator_nointr, IPL_NONE);
73 pool_init(&tmpfs_node_pool, sizeof(tmpfs_node_t), 0, 0, 0,
74 "tmpfs_node", &pool_allocator_nointr, IPL_NONE);
75}
76
77void
78tmpfs_done(void)
79{
80
81 pool_destroy(&tmpfs_dirent_pool);
82 pool_destroy(&tmpfs_node_pool);
83}
84
85int
86tmpfs_mount(struct mount *mp, const char *path, void *data, size_t *data_len)
87{
88 struct tmpfs_args *args = data;
89 tmpfs_mount_t *tmp;
90 tmpfs_node_t *root;
91 struct vattr va;
92 struct vnode *vp;
93 uint64_t memlimit;
94 ino_t nodes;
95 int error;
96 bool set_memlimit;
97 bool set_nodes;
98
99 if (args == NULL)
100 return EINVAL;
101
102 /* Validate the version. */
103 if (*data_len < sizeof(*args) ||
104 args->ta_version != TMPFS_ARGS_VERSION)
105 return EINVAL;
106
107 /* Handle retrieval of mount point arguments. */
108 if (mp->mnt_flag & MNT_GETARGS) {
109 if (mp->mnt_data == NULL)
110 return EIO;
111 tmp = VFS_TO_TMPFS(mp);
112
113 args->ta_version = TMPFS_ARGS_VERSION;
114 args->ta_nodes_max = tmp->tm_nodes_max;
115 args->ta_size_max = tmp->tm_mem_limit;
116
117 root = tmp->tm_root;
118 args->ta_root_uid = root->tn_uid;
119 args->ta_root_gid = root->tn_gid;
120 args->ta_root_mode = root->tn_mode;
121
122 *data_len = sizeof(*args);
123 return 0;
124 }
125
126
127 /* Prohibit mounts if there is not enough memory. */
128 if (tmpfs_mem_info(true) < uvmexp.freetarg)
129 return EINVAL;
130
131 /* Check for invalid uid and gid arguments */
132 if (args->ta_root_uid == VNOVAL || args->ta_root_gid == VNOVAL)
133 return EINVAL;
134
135 /* This can never happen? */
136 if ((args->ta_root_mode & ALLPERMS) == VNOVAL)
137 return EINVAL;
138
139 /* Get the memory usage limit for this file-system. */
140 if (args->ta_size_max < PAGE_SIZE) {
141 memlimit = UINT64_MAX;
142 set_memlimit = false;
143 } else {
144 memlimit = args->ta_size_max;
145 set_memlimit = true;
146 }
147 KASSERT(memlimit > 0);
148
149 if (args->ta_nodes_max <= 3) {
150 nodes = 3 + (memlimit / 1024);
151 set_nodes = false;
152 } else {
153 nodes = args->ta_nodes_max;
154 set_nodes = true;
155 }
156 nodes = MIN(nodes, INT_MAX);
157 KASSERT(nodes >= 3);
158
159 if (mp->mnt_flag & MNT_UPDATE) {
160 tmp = VFS_TO_TMPFS(mp);
161 if (set_nodes && nodes < tmp->tm_nodes_cnt)
162 return EBUSY;
163 if (set_memlimit) {
164 if ((error = tmpfs_mntmem_set(tmp, memlimit)) != 0)
165 return error;
166 }
167 if (set_nodes)
168 tmp->tm_nodes_max = nodes;
169 root = tmp->tm_root;
170 root->tn_uid = args->ta_root_uid;
171 root->tn_gid = args->ta_root_gid;
172 root->tn_mode = args->ta_root_mode;
173 return 0;
174 }
175
176 /* Allocate the tmpfs mount structure and fill it. */
177 tmp = kmem_zalloc(sizeof(tmpfs_mount_t), KM_SLEEP);
178 if (tmp == NULL)
179 return ENOMEM;
180
181 tmp->tm_nodes_max = nodes;
182 tmp->tm_nodes_cnt = 0;
183 LIST_INIT(&tmp->tm_nodes);
184
185 mutex_init(&tmp->tm_lock, MUTEX_DEFAULT, IPL_NONE);
186 tmpfs_mntmem_init(tmp, memlimit);
187 mp->mnt_data = tmp;
188
189 /* Allocate the root node. */
190 vattr_null(&va);
191 va.va_type = VDIR;
192 va.va_mode = args->ta_root_mode & ALLPERMS;
193 va.va_uid = args->ta_root_uid;
194 va.va_gid = args->ta_root_gid;
195 error = vcache_new(mp, NULL, &va, NOCRED, &vp);
196 if (error) {
197 mp->mnt_data = NULL;
198 tmpfs_mntmem_destroy(tmp);
199 mutex_destroy(&tmp->tm_lock);
200 kmem_free(tmp, sizeof(*tmp));
201 return error;
202 }
203 KASSERT(vp != NULL);
204 root = VP_TO_TMPFS_NODE(vp);
205 KASSERT(root != NULL);
206
207 /*
208 * Parent of the root inode is itself. Also, root inode has no
209 * directory entry (i.e. is never attached), thus hold an extra
210 * reference (link) for it.
211 */
212 root->tn_links++;
213 root->tn_spec.tn_dir.tn_parent = root;
214 tmp->tm_root = root;
215 vrele(vp);
216
217 mp->mnt_flag |= MNT_LOCAL;
218 mp->mnt_stat.f_namemax = TMPFS_MAXNAMLEN;
219 mp->mnt_fs_bshift = PAGE_SHIFT;
220 mp->mnt_dev_bshift = DEV_BSHIFT;
221 mp->mnt_iflag |= IMNT_MPSAFE | IMNT_CAN_RWTORO;
222 vfs_getnewfsid(mp);
223
224 error = set_statvfs_info(path, UIO_USERSPACE, "tmpfs", UIO_SYSSPACE,
225 mp->mnt_op->vfs_name, mp, curlwp);
226 if (error) {
227 (void)tmpfs_unmount(mp, MNT_FORCE);
228 }
229 return error;
230}
231
232int
233tmpfs_start(struct mount *mp, int flags)
234{
235
236 return 0;
237}
238
239int
240tmpfs_unmount(struct mount *mp, int mntflags)
241{
242 tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp);
243 tmpfs_node_t *node, *cnode;
244 int error, flags = 0;
245
246 /* Handle forced unmounts. */
247 if (mntflags & MNT_FORCE)
248 flags |= FORCECLOSE;
249
250 /* Finalize all pending I/O. */
251 error = vflush(mp, NULL, flags);
252 if (error != 0)
253 return error;
254
255 /*
256 * First round, detach and destroy all directory entries.
257 * Also, clear the pointers to the vnodes - they are gone.
258 */
259 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) {
260 tmpfs_dirent_t *de;
261
262 node->tn_vnode = NULL;
263 if (node->tn_type != VDIR) {
264 continue;
265 }
266 while ((de = TAILQ_FIRST(&node->tn_spec.tn_dir.tn_dir)) != NULL) {
267 cnode = de->td_node;
268 if (cnode && cnode != TMPFS_NODE_WHITEOUT) {
269 cnode->tn_vnode = NULL;
270 }
271 tmpfs_dir_detach(node, de);
272 tmpfs_free_dirent(tmp, de);
273 }
274 /* Extra virtual entry (itself for the root). */
275 node->tn_links--;
276 }
277
278 /* Release the reference on root (diagnostic). */
279 node = tmp->tm_root;
280 node->tn_links--;
281
282 /* Second round, destroy all inodes. */
283 while ((node = LIST_FIRST(&tmp->tm_nodes)) != NULL) {
284 tmpfs_free_node(tmp, node);
285 }
286
287 /* Throw away the tmpfs_mount structure. */
288 tmpfs_mntmem_destroy(tmp);
289 mutex_destroy(&tmp->tm_lock);
290 kmem_free(tmp, sizeof(*tmp));
291 mp->mnt_data = NULL;
292
293 return 0;
294}
295
296int
297tmpfs_root(struct mount *mp, vnode_t **vpp)
298{
299 tmpfs_node_t *node = VFS_TO_TMPFS(mp)->tm_root;
300 int error;
301
302 error = vcache_get(mp, &node, sizeof(node), vpp);
303 if (error)
304 return error;
305 error = vn_lock(*vpp, LK_EXCLUSIVE);
306 if (error) {
307 vrele(*vpp);
308 *vpp = NULL;
309 return error;
310 }
311
312 return 0;
313}
314
315int
316tmpfs_vget(struct mount *mp, ino_t ino, vnode_t **vpp)
317{
318
319 return EOPNOTSUPP;
320}
321
322int
323tmpfs_fhtovp(struct mount *mp, struct fid *fhp, vnode_t **vpp)
324{
325 tmpfs_mount_t *tmp = VFS_TO_TMPFS(mp);
326 tmpfs_node_t *node;
327 tmpfs_fid_t tfh;
328 int error;
329
330 if (fhp->fid_len != sizeof(tmpfs_fid_t)) {
331 return EINVAL;
332 }
333 memcpy(&tfh, fhp, sizeof(tmpfs_fid_t));
334
335 mutex_enter(&tmp->tm_lock);
336 LIST_FOREACH(node, &tmp->tm_nodes, tn_entries) {
337 if (node->tn_id == tfh.tf_id) {
338 /* Prevent this node from disappearing. */
339 atomic_inc_32(&node->tn_holdcount);
340 break;
341 }
342 }
343 mutex_exit(&tmp->tm_lock);
344 if (node == NULL)
345 return ESTALE;
346
347 error = vcache_get(mp, &node, sizeof(node), vpp);
348 /* If this node has been reclaimed free it now. */
349 if (atomic_dec_32_nv(&node->tn_holdcount) == TMPFS_NODE_RECLAIMED) {
350 KASSERT(error != 0);
351 tmpfs_free_node(tmp, node);
352 }
353 if (error)
354 return (error == ENOENT ? ESTALE : error);
355 error = vn_lock(*vpp, LK_EXCLUSIVE);
356 if (error) {
357 vrele(*vpp);
358 *vpp = NULL;
359 return error;
360 }
361 if (TMPFS_NODE_GEN(node) != tfh.tf_gen) {
362 vput(*vpp);
363 *vpp = NULL;
364 return ESTALE;
365 }
366
367 return 0;
368}
369
370int
371tmpfs_vptofh(vnode_t *vp, struct fid *fhp, size_t *fh_size)
372{
373 tmpfs_fid_t tfh;
374 tmpfs_node_t *node;
375
376 if (*fh_size < sizeof(tmpfs_fid_t)) {
377 *fh_size = sizeof(tmpfs_fid_t);
378 return E2BIG;
379 }
380 *fh_size = sizeof(tmpfs_fid_t);
381 node = VP_TO_TMPFS_NODE(vp);
382
383 memset(&tfh, 0, sizeof(tfh));
384 tfh.tf_len = sizeof(tmpfs_fid_t);
385 tfh.tf_gen = TMPFS_NODE_GEN(node);
386 tfh.tf_id = node->tn_id;
387 memcpy(fhp, &tfh, sizeof(tfh));
388
389 return 0;
390}
391
392int
393tmpfs_statvfs(struct mount *mp, struct statvfs *sbp)
394{
395 tmpfs_mount_t *tmp;
396 fsfilcnt_t freenodes;
397 size_t avail;
398
399 tmp = VFS_TO_TMPFS(mp);
400
401 sbp->f_iosize = sbp->f_frsize = sbp->f_bsize = PAGE_SIZE;
402
403 mutex_enter(&tmp->tm_acc_lock);
404 avail = tmpfs_pages_avail(tmp);
405 sbp->f_blocks = (tmpfs_bytes_max(tmp) >> PAGE_SHIFT);
406 sbp->f_bavail = sbp->f_bfree = avail;
407 sbp->f_bresvd = 0;
408
409 freenodes = MIN(tmp->tm_nodes_max - tmp->tm_nodes_cnt,
410 avail * PAGE_SIZE / sizeof(tmpfs_node_t));
411
412 sbp->f_files = tmp->tm_nodes_cnt + freenodes;
413 sbp->f_favail = sbp->f_ffree = freenodes;
414 sbp->f_fresvd = 0;
415 mutex_exit(&tmp->tm_acc_lock);
416
417 copy_statvfs_info(sbp, mp);
418
419 return 0;
420}
421
422int
423tmpfs_sync(struct mount *mp, int waitfor, kauth_cred_t uc)
424{
425
426 return 0;
427}
428
429int
430tmpfs_snapshot(struct mount *mp, vnode_t *vp, struct timespec *ctime)
431{
432
433 return EOPNOTSUPP;
434}
435
436/*
437 * tmpfs vfs operations.
438 */
439
440extern const struct vnodeopv_desc tmpfs_fifoop_opv_desc;
441extern const struct vnodeopv_desc tmpfs_specop_opv_desc;
442extern const struct vnodeopv_desc tmpfs_vnodeop_opv_desc;
443
444const struct vnodeopv_desc * const tmpfs_vnodeopv_descs[] = {
445 &tmpfs_fifoop_opv_desc,
446 &tmpfs_specop_opv_desc,
447 &tmpfs_vnodeop_opv_desc,
448 NULL,
449};
450
451struct vfsops tmpfs_vfsops = {
452 .vfs_name = MOUNT_TMPFS,
453 .vfs_min_mount_data = sizeof (struct tmpfs_args),
454 .vfs_mount = tmpfs_mount,
455 .vfs_start = tmpfs_start,
456 .vfs_unmount = tmpfs_unmount,
457 .vfs_root = tmpfs_root,
458 .vfs_quotactl = (void *)eopnotsupp,
459 .vfs_statvfs = tmpfs_statvfs,
460 .vfs_sync = tmpfs_sync,
461 .vfs_vget = tmpfs_vget,
462 .vfs_loadvnode = tmpfs_loadvnode,
463 .vfs_newvnode = tmpfs_newvnode,
464 .vfs_fhtovp = tmpfs_fhtovp,
465 .vfs_vptofh = tmpfs_vptofh,
466 .vfs_init = tmpfs_init,
467 .vfs_done = tmpfs_done,
468 .vfs_snapshot = tmpfs_snapshot,
469 .vfs_extattrctl = vfs_stdextattrctl,
470 .vfs_suspendctl = (void *)eopnotsupp,
471 .vfs_renamelock_enter = genfs_renamelock_enter,
472 .vfs_renamelock_exit = genfs_renamelock_exit,
473 .vfs_fsync = (void *)eopnotsupp,
474 .vfs_opv_descs = tmpfs_vnodeopv_descs
475};
476
477static int
478tmpfs_modcmd(modcmd_t cmd, void *arg)
479{
480
481 switch (cmd) {
482 case MODULE_CMD_INIT:
483 return vfs_attach(&tmpfs_vfsops);
484 case MODULE_CMD_FINI:
485 return vfs_detach(&tmpfs_vfsops);
486 default:
487 return ENOTTY;
488 }
489}
490