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Commit | Line | Data |
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e9be9d5e MS |
1 | /* |
2 | * | |
3 | * Copyright (C) 2011 Novell Inc. | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify it | |
6 | * under the terms of the GNU General Public License version 2 as published by | |
7 | * the Free Software Foundation. | |
8 | */ | |
9 | ||
5b825c3a | 10 | #include <uapi/linux/magic.h> |
e9be9d5e MS |
11 | #include <linux/fs.h> |
12 | #include <linux/namei.h> | |
13 | #include <linux/xattr.h> | |
e9be9d5e | 14 | #include <linux/mount.h> |
e9be9d5e MS |
15 | #include <linux/parser.h> |
16 | #include <linux/module.h> | |
cc259639 | 17 | #include <linux/statfs.h> |
f45827e8 | 18 | #include <linux/seq_file.h> |
d837a49b | 19 | #include <linux/posix_acl_xattr.h> |
e9be9d5e | 20 | #include "overlayfs.h" |
bbb1e54d | 21 | #include "ovl_entry.h" |
e9be9d5e MS |
22 | |
23 | MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); | |
24 | MODULE_DESCRIPTION("Overlay filesystem"); | |
25 | MODULE_LICENSE("GPL"); | |
26 | ||
e9be9d5e MS |
27 | |
28 | struct ovl_dir_cache; | |
29 | ||
a78d9f0d MS |
30 | #define OVL_MAX_STACK 500 |
31 | ||
688ea0e5 MS |
32 | static bool ovl_redirect_dir_def = IS_ENABLED(CONFIG_OVERLAY_FS_REDIRECT_DIR); |
33 | module_param_named(redirect_dir, ovl_redirect_dir_def, bool, 0644); | |
34 | MODULE_PARM_DESC(ovl_redirect_dir_def, | |
35 | "Default to on or off for the redirect_dir feature"); | |
e9be9d5e MS |
36 | |
37 | static void ovl_dentry_release(struct dentry *dentry) | |
38 | { | |
39 | struct ovl_entry *oe = dentry->d_fsdata; | |
40 | ||
41 | if (oe) { | |
dd662667 MS |
42 | unsigned int i; |
43 | ||
e9be9d5e | 44 | dput(oe->__upperdentry); |
02b69b28 | 45 | kfree(oe->redirect); |
dd662667 MS |
46 | for (i = 0; i < oe->numlower; i++) |
47 | dput(oe->lowerstack[i].dentry); | |
e9be9d5e MS |
48 | kfree_rcu(oe, rcu); |
49 | } | |
50 | } | |
51 | ||
b0990fbb AG |
52 | static int ovl_check_append_only(struct inode *inode, int flag) |
53 | { | |
54 | /* | |
55 | * This test was moot in vfs may_open() because overlay inode does | |
56 | * not have the S_APPEND flag, so re-check on real upper inode | |
57 | */ | |
58 | if (IS_APPEND(inode)) { | |
59 | if ((flag & O_ACCMODE) != O_RDONLY && !(flag & O_APPEND)) | |
60 | return -EPERM; | |
61 | if (flag & O_TRUNC) | |
62 | return -EPERM; | |
63 | } | |
64 | ||
65 | return 0; | |
66 | } | |
67 | ||
2d902671 MS |
68 | static struct dentry *ovl_d_real(struct dentry *dentry, |
69 | const struct inode *inode, | |
70 | unsigned int open_flags) | |
d101a125 MS |
71 | { |
72 | struct dentry *real; | |
b0990fbb | 73 | int err; |
d101a125 | 74 | |
ca4c8a3a | 75 | if (!d_is_reg(dentry)) { |
d101a125 MS |
76 | if (!inode || inode == d_inode(dentry)) |
77 | return dentry; | |
78 | goto bug; | |
79 | } | |
80 | ||
2d902671 MS |
81 | if (d_is_negative(dentry)) |
82 | return dentry; | |
83 | ||
84 | if (open_flags) { | |
b0990fbb | 85 | err = ovl_open_maybe_copy_up(dentry, open_flags); |
2d902671 MS |
86 | if (err) |
87 | return ERR_PTR(err); | |
88 | } | |
89 | ||
d101a125 | 90 | real = ovl_dentry_upper(dentry); |
b0990fbb AG |
91 | if (real && (!inode || inode == d_inode(real))) { |
92 | if (!inode) { | |
93 | err = ovl_check_append_only(d_inode(real), open_flags); | |
94 | if (err) | |
95 | return ERR_PTR(err); | |
96 | } | |
d101a125 | 97 | return real; |
b0990fbb | 98 | } |
d101a125 MS |
99 | |
100 | real = ovl_dentry_lower(dentry); | |
101 | if (!real) | |
102 | goto bug; | |
103 | ||
c4fcfc16 MS |
104 | /* Handle recursion */ |
105 | real = d_real(real, inode, open_flags); | |
106 | ||
d101a125 MS |
107 | if (!inode || inode == d_inode(real)) |
108 | return real; | |
d101a125 | 109 | bug: |
656189d2 | 110 | WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry, |
d101a125 MS |
111 | inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0); |
112 | return dentry; | |
113 | } | |
114 | ||
7c03b5d4 MS |
115 | static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
116 | { | |
117 | struct ovl_entry *oe = dentry->d_fsdata; | |
118 | unsigned int i; | |
119 | int ret = 1; | |
120 | ||
121 | for (i = 0; i < oe->numlower; i++) { | |
122 | struct dentry *d = oe->lowerstack[i].dentry; | |
123 | ||
124 | if (d->d_flags & DCACHE_OP_REVALIDATE) { | |
125 | ret = d->d_op->d_revalidate(d, flags); | |
126 | if (ret < 0) | |
127 | return ret; | |
128 | if (!ret) { | |
129 | if (!(flags & LOOKUP_RCU)) | |
130 | d_invalidate(d); | |
131 | return -ESTALE; | |
132 | } | |
133 | } | |
134 | } | |
135 | return 1; | |
136 | } | |
137 | ||
138 | static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) | |
139 | { | |
140 | struct ovl_entry *oe = dentry->d_fsdata; | |
141 | unsigned int i; | |
142 | int ret = 1; | |
143 | ||
144 | for (i = 0; i < oe->numlower; i++) { | |
145 | struct dentry *d = oe->lowerstack[i].dentry; | |
146 | ||
147 | if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) { | |
148 | ret = d->d_op->d_weak_revalidate(d, flags); | |
149 | if (ret <= 0) | |
150 | break; | |
151 | } | |
152 | } | |
153 | return ret; | |
154 | } | |
155 | ||
e9be9d5e MS |
156 | static const struct dentry_operations ovl_dentry_operations = { |
157 | .d_release = ovl_dentry_release, | |
d101a125 | 158 | .d_real = ovl_d_real, |
e9be9d5e MS |
159 | }; |
160 | ||
7c03b5d4 MS |
161 | static const struct dentry_operations ovl_reval_dentry_operations = { |
162 | .d_release = ovl_dentry_release, | |
d101a125 | 163 | .d_real = ovl_d_real, |
7c03b5d4 MS |
164 | .d_revalidate = ovl_dentry_revalidate, |
165 | .d_weak_revalidate = ovl_dentry_weak_revalidate, | |
166 | }; | |
167 | ||
e9be9d5e MS |
168 | static void ovl_put_super(struct super_block *sb) |
169 | { | |
170 | struct ovl_fs *ufs = sb->s_fs_info; | |
dd662667 | 171 | unsigned i; |
e9be9d5e MS |
172 | |
173 | dput(ufs->workdir); | |
174 | mntput(ufs->upper_mnt); | |
dd662667 MS |
175 | for (i = 0; i < ufs->numlower; i++) |
176 | mntput(ufs->lower_mnt[i]); | |
5ffdbe8b | 177 | kfree(ufs->lower_mnt); |
e9be9d5e | 178 | |
f45827e8 EZ |
179 | kfree(ufs->config.lowerdir); |
180 | kfree(ufs->config.upperdir); | |
181 | kfree(ufs->config.workdir); | |
3fe6e52f | 182 | put_cred(ufs->creator_cred); |
e9be9d5e MS |
183 | kfree(ufs); |
184 | } | |
185 | ||
e593b2bf AG |
186 | static int ovl_sync_fs(struct super_block *sb, int wait) |
187 | { | |
188 | struct ovl_fs *ufs = sb->s_fs_info; | |
189 | struct super_block *upper_sb; | |
190 | int ret; | |
191 | ||
192 | if (!ufs->upper_mnt) | |
193 | return 0; | |
194 | upper_sb = ufs->upper_mnt->mnt_sb; | |
195 | if (!upper_sb->s_op->sync_fs) | |
196 | return 0; | |
197 | ||
198 | /* real inodes have already been synced by sync_filesystem(ovl_sb) */ | |
199 | down_read(&upper_sb->s_umount); | |
200 | ret = upper_sb->s_op->sync_fs(upper_sb, wait); | |
201 | up_read(&upper_sb->s_umount); | |
202 | return ret; | |
203 | } | |
204 | ||
cc259639 AW |
205 | /** |
206 | * ovl_statfs | |
207 | * @sb: The overlayfs super block | |
208 | * @buf: The struct kstatfs to fill in with stats | |
209 | * | |
210 | * Get the filesystem statistics. As writes always target the upper layer | |
4ebc5818 | 211 | * filesystem pass the statfs to the upper filesystem (if it exists) |
cc259639 AW |
212 | */ |
213 | static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) | |
214 | { | |
215 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
216 | struct dentry *root_dentry = dentry->d_sb->s_root; | |
217 | struct path path; | |
218 | int err; | |
219 | ||
4ebc5818 | 220 | ovl_path_real(root_dentry, &path); |
cc259639 AW |
221 | |
222 | err = vfs_statfs(&path, buf); | |
223 | if (!err) { | |
6b2d5fe4 | 224 | buf->f_namelen = ofs->namelen; |
cc259639 AW |
225 | buf->f_type = OVERLAYFS_SUPER_MAGIC; |
226 | } | |
227 | ||
228 | return err; | |
229 | } | |
230 | ||
f45827e8 EZ |
231 | /** |
232 | * ovl_show_options | |
233 | * | |
234 | * Prints the mount options for a given superblock. | |
235 | * Returns zero; does not fail. | |
236 | */ | |
237 | static int ovl_show_options(struct seq_file *m, struct dentry *dentry) | |
238 | { | |
239 | struct super_block *sb = dentry->d_sb; | |
240 | struct ovl_fs *ufs = sb->s_fs_info; | |
241 | ||
a068acf2 | 242 | seq_show_option(m, "lowerdir", ufs->config.lowerdir); |
53a08cb9 | 243 | if (ufs->config.upperdir) { |
a068acf2 KC |
244 | seq_show_option(m, "upperdir", ufs->config.upperdir); |
245 | seq_show_option(m, "workdir", ufs->config.workdir); | |
53a08cb9 | 246 | } |
8d3095f4 MS |
247 | if (ufs->config.default_permissions) |
248 | seq_puts(m, ",default_permissions"); | |
c5bef3a7 AG |
249 | if (ufs->config.redirect_dir != ovl_redirect_dir_def) |
250 | seq_printf(m, ",redirect_dir=%s", | |
251 | ufs->config.redirect_dir ? "on" : "off"); | |
f45827e8 EZ |
252 | return 0; |
253 | } | |
254 | ||
3cdf6fe9 SL |
255 | static int ovl_remount(struct super_block *sb, int *flags, char *data) |
256 | { | |
257 | struct ovl_fs *ufs = sb->s_fs_info; | |
258 | ||
cc6f67bc | 259 | if (!(*flags & MS_RDONLY) && (!ufs->upper_mnt || !ufs->workdir)) |
3cdf6fe9 SL |
260 | return -EROFS; |
261 | ||
262 | return 0; | |
263 | } | |
264 | ||
e9be9d5e MS |
265 | static const struct super_operations ovl_super_operations = { |
266 | .put_super = ovl_put_super, | |
e593b2bf | 267 | .sync_fs = ovl_sync_fs, |
cc259639 | 268 | .statfs = ovl_statfs, |
f45827e8 | 269 | .show_options = ovl_show_options, |
3cdf6fe9 | 270 | .remount_fs = ovl_remount, |
eead4f2d | 271 | .drop_inode = generic_delete_inode, |
e9be9d5e MS |
272 | }; |
273 | ||
274 | enum { | |
275 | OPT_LOWERDIR, | |
276 | OPT_UPPERDIR, | |
277 | OPT_WORKDIR, | |
8d3095f4 | 278 | OPT_DEFAULT_PERMISSIONS, |
a6c60655 MS |
279 | OPT_REDIRECT_DIR_ON, |
280 | OPT_REDIRECT_DIR_OFF, | |
e9be9d5e MS |
281 | OPT_ERR, |
282 | }; | |
283 | ||
284 | static const match_table_t ovl_tokens = { | |
285 | {OPT_LOWERDIR, "lowerdir=%s"}, | |
286 | {OPT_UPPERDIR, "upperdir=%s"}, | |
287 | {OPT_WORKDIR, "workdir=%s"}, | |
8d3095f4 | 288 | {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, |
a6c60655 MS |
289 | {OPT_REDIRECT_DIR_ON, "redirect_dir=on"}, |
290 | {OPT_REDIRECT_DIR_OFF, "redirect_dir=off"}, | |
e9be9d5e MS |
291 | {OPT_ERR, NULL} |
292 | }; | |
293 | ||
91c77947 MS |
294 | static char *ovl_next_opt(char **s) |
295 | { | |
296 | char *sbegin = *s; | |
297 | char *p; | |
298 | ||
299 | if (sbegin == NULL) | |
300 | return NULL; | |
301 | ||
302 | for (p = sbegin; *p; p++) { | |
303 | if (*p == '\\') { | |
304 | p++; | |
305 | if (!*p) | |
306 | break; | |
307 | } else if (*p == ',') { | |
308 | *p = '\0'; | |
309 | *s = p + 1; | |
310 | return sbegin; | |
311 | } | |
312 | } | |
313 | *s = NULL; | |
314 | return sbegin; | |
315 | } | |
316 | ||
e9be9d5e MS |
317 | static int ovl_parse_opt(char *opt, struct ovl_config *config) |
318 | { | |
319 | char *p; | |
320 | ||
91c77947 | 321 | while ((p = ovl_next_opt(&opt)) != NULL) { |
e9be9d5e MS |
322 | int token; |
323 | substring_t args[MAX_OPT_ARGS]; | |
324 | ||
325 | if (!*p) | |
326 | continue; | |
327 | ||
328 | token = match_token(p, ovl_tokens, args); | |
329 | switch (token) { | |
330 | case OPT_UPPERDIR: | |
331 | kfree(config->upperdir); | |
332 | config->upperdir = match_strdup(&args[0]); | |
333 | if (!config->upperdir) | |
334 | return -ENOMEM; | |
335 | break; | |
336 | ||
337 | case OPT_LOWERDIR: | |
338 | kfree(config->lowerdir); | |
339 | config->lowerdir = match_strdup(&args[0]); | |
340 | if (!config->lowerdir) | |
341 | return -ENOMEM; | |
342 | break; | |
343 | ||
344 | case OPT_WORKDIR: | |
345 | kfree(config->workdir); | |
346 | config->workdir = match_strdup(&args[0]); | |
347 | if (!config->workdir) | |
348 | return -ENOMEM; | |
349 | break; | |
350 | ||
8d3095f4 MS |
351 | case OPT_DEFAULT_PERMISSIONS: |
352 | config->default_permissions = true; | |
353 | break; | |
354 | ||
a6c60655 MS |
355 | case OPT_REDIRECT_DIR_ON: |
356 | config->redirect_dir = true; | |
357 | break; | |
358 | ||
359 | case OPT_REDIRECT_DIR_OFF: | |
360 | config->redirect_dir = false; | |
361 | break; | |
362 | ||
e9be9d5e | 363 | default: |
bead55ef | 364 | pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p); |
e9be9d5e MS |
365 | return -EINVAL; |
366 | } | |
367 | } | |
71cbad7e | 368 | |
369 | /* Workdir is useless in non-upper mount */ | |
370 | if (!config->upperdir && config->workdir) { | |
371 | pr_info("overlayfs: option \"workdir=%s\" is useless in a non-upper mount, ignore\n", | |
372 | config->workdir); | |
373 | kfree(config->workdir); | |
374 | config->workdir = NULL; | |
375 | } | |
376 | ||
e9be9d5e MS |
377 | return 0; |
378 | } | |
379 | ||
380 | #define OVL_WORKDIR_NAME "work" | |
381 | ||
382 | static struct dentry *ovl_workdir_create(struct vfsmount *mnt, | |
383 | struct dentry *dentry) | |
384 | { | |
385 | struct inode *dir = dentry->d_inode; | |
386 | struct dentry *work; | |
387 | int err; | |
388 | bool retried = false; | |
389 | ||
390 | err = mnt_want_write(mnt); | |
391 | if (err) | |
392 | return ERR_PTR(err); | |
393 | ||
5955102c | 394 | inode_lock_nested(dir, I_MUTEX_PARENT); |
e9be9d5e MS |
395 | retry: |
396 | work = lookup_one_len(OVL_WORKDIR_NAME, dentry, | |
397 | strlen(OVL_WORKDIR_NAME)); | |
398 | ||
399 | if (!IS_ERR(work)) { | |
c11b9fdd MS |
400 | struct iattr attr = { |
401 | .ia_valid = ATTR_MODE, | |
32a3d848 | 402 | .ia_mode = S_IFDIR | 0, |
c11b9fdd | 403 | }; |
e9be9d5e MS |
404 | |
405 | if (work->d_inode) { | |
406 | err = -EEXIST; | |
407 | if (retried) | |
408 | goto out_dput; | |
409 | ||
410 | retried = true; | |
eea2fb48 | 411 | ovl_workdir_cleanup(dir, mnt, work, 0); |
e9be9d5e MS |
412 | dput(work); |
413 | goto retry; | |
414 | } | |
415 | ||
32a3d848 AV |
416 | err = ovl_create_real(dir, work, |
417 | &(struct cattr){.mode = S_IFDIR | 0}, | |
418 | NULL, true); | |
e9be9d5e MS |
419 | if (err) |
420 | goto out_dput; | |
c11b9fdd | 421 | |
cb348edb MS |
422 | /* |
423 | * Try to remove POSIX ACL xattrs from workdir. We are good if: | |
424 | * | |
425 | * a) success (there was a POSIX ACL xattr and was removed) | |
426 | * b) -ENODATA (there was no POSIX ACL xattr) | |
427 | * c) -EOPNOTSUPP (POSIX ACL xattrs are not supported) | |
428 | * | |
429 | * There are various other error values that could effectively | |
430 | * mean that the xattr doesn't exist (e.g. -ERANGE is returned | |
431 | * if the xattr name is too long), but the set of filesystems | |
432 | * allowed as upper are limited to "normal" ones, where checking | |
433 | * for the above two errors is sufficient. | |
434 | */ | |
c11b9fdd | 435 | err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_DEFAULT); |
e1ff3dd1 | 436 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
437 | goto out_dput; |
438 | ||
439 | err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_ACCESS); | |
e1ff3dd1 | 440 | if (err && err != -ENODATA && err != -EOPNOTSUPP) |
c11b9fdd MS |
441 | goto out_dput; |
442 | ||
443 | /* Clear any inherited mode bits */ | |
444 | inode_lock(work->d_inode); | |
445 | err = notify_change(work, &attr, NULL); | |
446 | inode_unlock(work->d_inode); | |
447 | if (err) | |
448 | goto out_dput; | |
e9be9d5e MS |
449 | } |
450 | out_unlock: | |
5955102c | 451 | inode_unlock(dir); |
e9be9d5e MS |
452 | mnt_drop_write(mnt); |
453 | ||
454 | return work; | |
455 | ||
456 | out_dput: | |
457 | dput(work); | |
458 | work = ERR_PTR(err); | |
459 | goto out_unlock; | |
460 | } | |
461 | ||
91c77947 MS |
462 | static void ovl_unescape(char *s) |
463 | { | |
464 | char *d = s; | |
465 | ||
466 | for (;; s++, d++) { | |
467 | if (*s == '\\') | |
468 | s++; | |
469 | *d = *s; | |
470 | if (!*s) | |
471 | break; | |
472 | } | |
473 | } | |
474 | ||
ab508822 MS |
475 | static int ovl_mount_dir_noesc(const char *name, struct path *path) |
476 | { | |
a78d9f0d | 477 | int err = -EINVAL; |
ab508822 | 478 | |
a78d9f0d MS |
479 | if (!*name) { |
480 | pr_err("overlayfs: empty lowerdir\n"); | |
481 | goto out; | |
482 | } | |
ab508822 MS |
483 | err = kern_path(name, LOOKUP_FOLLOW, path); |
484 | if (err) { | |
485 | pr_err("overlayfs: failed to resolve '%s': %i\n", name, err); | |
486 | goto out; | |
487 | } | |
488 | err = -EINVAL; | |
7c03b5d4 | 489 | if (ovl_dentry_weird(path->dentry)) { |
ab508822 MS |
490 | pr_err("overlayfs: filesystem on '%s' not supported\n", name); |
491 | goto out_put; | |
492 | } | |
2b8c30e9 | 493 | if (!d_is_dir(path->dentry)) { |
ab508822 MS |
494 | pr_err("overlayfs: '%s' not a directory\n", name); |
495 | goto out_put; | |
496 | } | |
497 | return 0; | |
498 | ||
499 | out_put: | |
500 | path_put(path); | |
501 | out: | |
502 | return err; | |
503 | } | |
504 | ||
505 | static int ovl_mount_dir(const char *name, struct path *path) | |
506 | { | |
507 | int err = -ENOMEM; | |
508 | char *tmp = kstrdup(name, GFP_KERNEL); | |
509 | ||
510 | if (tmp) { | |
511 | ovl_unescape(tmp); | |
512 | err = ovl_mount_dir_noesc(tmp, path); | |
7c03b5d4 MS |
513 | |
514 | if (!err) | |
515 | if (ovl_dentry_remote(path->dentry)) { | |
516 | pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n", | |
517 | tmp); | |
518 | path_put(path); | |
519 | err = -EINVAL; | |
520 | } | |
ab508822 MS |
521 | kfree(tmp); |
522 | } | |
523 | return err; | |
524 | } | |
525 | ||
6b2d5fe4 MS |
526 | static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs, |
527 | const char *name) | |
ab508822 | 528 | { |
ab508822 | 529 | struct kstatfs statfs; |
6b2d5fe4 MS |
530 | int err = vfs_statfs(path, &statfs); |
531 | ||
532 | if (err) | |
533 | pr_err("overlayfs: statfs failed on '%s'\n", name); | |
534 | else | |
535 | ofs->namelen = max(ofs->namelen, statfs.f_namelen); | |
536 | ||
537 | return err; | |
538 | } | |
539 | ||
540 | static int ovl_lower_dir(const char *name, struct path *path, | |
541 | struct ovl_fs *ofs, int *stack_depth, bool *remote) | |
542 | { | |
543 | int err; | |
ab508822 | 544 | |
a78d9f0d | 545 | err = ovl_mount_dir_noesc(name, path); |
ab508822 MS |
546 | if (err) |
547 | goto out; | |
548 | ||
6b2d5fe4 MS |
549 | err = ovl_check_namelen(path, ofs, name); |
550 | if (err) | |
ab508822 | 551 | goto out_put; |
6b2d5fe4 | 552 | |
ab508822 MS |
553 | *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); |
554 | ||
7c03b5d4 MS |
555 | if (ovl_dentry_remote(path->dentry)) |
556 | *remote = true; | |
557 | ||
ab508822 MS |
558 | return 0; |
559 | ||
560 | out_put: | |
561 | path_put(path); | |
562 | out: | |
563 | return err; | |
564 | } | |
565 | ||
e9be9d5e MS |
566 | /* Workdir should not be subdir of upperdir and vice versa */ |
567 | static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) | |
568 | { | |
569 | bool ok = false; | |
570 | ||
571 | if (workdir != upperdir) { | |
572 | ok = (lock_rename(workdir, upperdir) == NULL); | |
573 | unlock_rename(workdir, upperdir); | |
574 | } | |
575 | return ok; | |
576 | } | |
577 | ||
a78d9f0d MS |
578 | static unsigned int ovl_split_lowerdirs(char *str) |
579 | { | |
580 | unsigned int ctr = 1; | |
581 | char *s, *d; | |
582 | ||
583 | for (s = d = str;; s++, d++) { | |
584 | if (*s == '\\') { | |
585 | s++; | |
586 | } else if (*s == ':') { | |
587 | *d = '\0'; | |
588 | ctr++; | |
589 | continue; | |
590 | } | |
591 | *d = *s; | |
592 | if (!*s) | |
593 | break; | |
594 | } | |
595 | return ctr; | |
596 | } | |
597 | ||
0eb45fc3 AG |
598 | static int __maybe_unused |
599 | ovl_posix_acl_xattr_get(const struct xattr_handler *handler, | |
600 | struct dentry *dentry, struct inode *inode, | |
601 | const char *name, void *buffer, size_t size) | |
602 | { | |
603 | return ovl_xattr_get(dentry, handler->name, buffer, size); | |
604 | } | |
605 | ||
0c97be22 AG |
606 | static int __maybe_unused |
607 | ovl_posix_acl_xattr_set(const struct xattr_handler *handler, | |
608 | struct dentry *dentry, struct inode *inode, | |
609 | const char *name, const void *value, | |
610 | size_t size, int flags) | |
d837a49b MS |
611 | { |
612 | struct dentry *workdir = ovl_workdir(dentry); | |
613 | struct inode *realinode = ovl_inode_real(inode, NULL); | |
614 | struct posix_acl *acl = NULL; | |
615 | int err; | |
616 | ||
617 | /* Check that everything is OK before copy-up */ | |
618 | if (value) { | |
619 | acl = posix_acl_from_xattr(&init_user_ns, value, size); | |
620 | if (IS_ERR(acl)) | |
621 | return PTR_ERR(acl); | |
622 | } | |
623 | err = -EOPNOTSUPP; | |
624 | if (!IS_POSIXACL(d_inode(workdir))) | |
625 | goto out_acl_release; | |
626 | if (!realinode->i_op->set_acl) | |
627 | goto out_acl_release; | |
628 | if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) { | |
629 | err = acl ? -EACCES : 0; | |
630 | goto out_acl_release; | |
631 | } | |
632 | err = -EPERM; | |
633 | if (!inode_owner_or_capable(inode)) | |
634 | goto out_acl_release; | |
635 | ||
636 | posix_acl_release(acl); | |
637 | ||
fd3220d3 MS |
638 | /* |
639 | * Check if sgid bit needs to be cleared (actual setacl operation will | |
640 | * be done with mounter's capabilities and so that won't do it for us). | |
641 | */ | |
642 | if (unlikely(inode->i_mode & S_ISGID) && | |
643 | handler->flags == ACL_TYPE_ACCESS && | |
644 | !in_group_p(inode->i_gid) && | |
645 | !capable_wrt_inode_uidgid(inode, CAP_FSETID)) { | |
646 | struct iattr iattr = { .ia_valid = ATTR_KILL_SGID }; | |
647 | ||
648 | err = ovl_setattr(dentry, &iattr); | |
649 | if (err) | |
650 | return err; | |
651 | } | |
652 | ||
ce31513a MS |
653 | err = ovl_xattr_set(dentry, handler->name, value, size, flags); |
654 | if (!err) | |
655 | ovl_copyattr(ovl_inode_real(inode, NULL), inode); | |
656 | ||
657 | return err; | |
d837a49b MS |
658 | |
659 | out_acl_release: | |
660 | posix_acl_release(acl); | |
661 | return err; | |
662 | } | |
663 | ||
0eb45fc3 AG |
664 | static int ovl_own_xattr_get(const struct xattr_handler *handler, |
665 | struct dentry *dentry, struct inode *inode, | |
666 | const char *name, void *buffer, size_t size) | |
667 | { | |
48fab5d7 | 668 | return -EOPNOTSUPP; |
0eb45fc3 AG |
669 | } |
670 | ||
d837a49b MS |
671 | static int ovl_own_xattr_set(const struct xattr_handler *handler, |
672 | struct dentry *dentry, struct inode *inode, | |
673 | const char *name, const void *value, | |
674 | size_t size, int flags) | |
675 | { | |
48fab5d7 | 676 | return -EOPNOTSUPP; |
d837a49b MS |
677 | } |
678 | ||
0eb45fc3 AG |
679 | static int ovl_other_xattr_get(const struct xattr_handler *handler, |
680 | struct dentry *dentry, struct inode *inode, | |
681 | const char *name, void *buffer, size_t size) | |
682 | { | |
683 | return ovl_xattr_get(dentry, name, buffer, size); | |
684 | } | |
685 | ||
0e585ccc AG |
686 | static int ovl_other_xattr_set(const struct xattr_handler *handler, |
687 | struct dentry *dentry, struct inode *inode, | |
688 | const char *name, const void *value, | |
689 | size_t size, int flags) | |
690 | { | |
691 | return ovl_xattr_set(dentry, name, value, size, flags); | |
692 | } | |
693 | ||
0c97be22 AG |
694 | static const struct xattr_handler __maybe_unused |
695 | ovl_posix_acl_access_xattr_handler = { | |
d837a49b MS |
696 | .name = XATTR_NAME_POSIX_ACL_ACCESS, |
697 | .flags = ACL_TYPE_ACCESS, | |
0eb45fc3 | 698 | .get = ovl_posix_acl_xattr_get, |
d837a49b MS |
699 | .set = ovl_posix_acl_xattr_set, |
700 | }; | |
701 | ||
0c97be22 AG |
702 | static const struct xattr_handler __maybe_unused |
703 | ovl_posix_acl_default_xattr_handler = { | |
d837a49b MS |
704 | .name = XATTR_NAME_POSIX_ACL_DEFAULT, |
705 | .flags = ACL_TYPE_DEFAULT, | |
0eb45fc3 | 706 | .get = ovl_posix_acl_xattr_get, |
d837a49b MS |
707 | .set = ovl_posix_acl_xattr_set, |
708 | }; | |
709 | ||
710 | static const struct xattr_handler ovl_own_xattr_handler = { | |
711 | .prefix = OVL_XATTR_PREFIX, | |
0eb45fc3 | 712 | .get = ovl_own_xattr_get, |
d837a49b MS |
713 | .set = ovl_own_xattr_set, |
714 | }; | |
715 | ||
716 | static const struct xattr_handler ovl_other_xattr_handler = { | |
717 | .prefix = "", /* catch all */ | |
0eb45fc3 | 718 | .get = ovl_other_xattr_get, |
d837a49b MS |
719 | .set = ovl_other_xattr_set, |
720 | }; | |
721 | ||
722 | static const struct xattr_handler *ovl_xattr_handlers[] = { | |
0c97be22 | 723 | #ifdef CONFIG_FS_POSIX_ACL |
d837a49b MS |
724 | &ovl_posix_acl_access_xattr_handler, |
725 | &ovl_posix_acl_default_xattr_handler, | |
0c97be22 | 726 | #endif |
d837a49b MS |
727 | &ovl_own_xattr_handler, |
728 | &ovl_other_xattr_handler, | |
729 | NULL | |
730 | }; | |
731 | ||
e9be9d5e MS |
732 | static int ovl_fill_super(struct super_block *sb, void *data, int silent) |
733 | { | |
33006cdf KC |
734 | struct path upperpath = { }; |
735 | struct path workpath = { }; | |
e9be9d5e | 736 | struct dentry *root_dentry; |
39b681f8 | 737 | struct inode *realinode; |
e9be9d5e MS |
738 | struct ovl_entry *oe; |
739 | struct ovl_fs *ufs; | |
a78d9f0d MS |
740 | struct path *stack = NULL; |
741 | char *lowertmp; | |
742 | char *lower; | |
743 | unsigned int numlower; | |
744 | unsigned int stacklen = 0; | |
dd662667 | 745 | unsigned int i; |
7c03b5d4 | 746 | bool remote = false; |
51f8f3c4 | 747 | struct cred *cred; |
e9be9d5e MS |
748 | int err; |
749 | ||
f45827e8 EZ |
750 | err = -ENOMEM; |
751 | ufs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); | |
752 | if (!ufs) | |
e9be9d5e MS |
753 | goto out; |
754 | ||
39d3d60a | 755 | init_waitqueue_head(&ufs->copyup_wq); |
688ea0e5 | 756 | ufs->config.redirect_dir = ovl_redirect_dir_def; |
f45827e8 EZ |
757 | err = ovl_parse_opt((char *) data, &ufs->config); |
758 | if (err) | |
759 | goto out_free_config; | |
760 | ||
e9be9d5e | 761 | err = -EINVAL; |
53a08cb9 | 762 | if (!ufs->config.lowerdir) { |
07f2af7b KK |
763 | if (!silent) |
764 | pr_err("overlayfs: missing 'lowerdir'\n"); | |
e9be9d5e MS |
765 | goto out_free_config; |
766 | } | |
767 | ||
53a08cb9 | 768 | sb->s_stack_depth = 0; |
cf9a6784 | 769 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
53a08cb9 | 770 | if (ufs->config.upperdir) { |
53a08cb9 MS |
771 | if (!ufs->config.workdir) { |
772 | pr_err("overlayfs: missing 'workdir'\n"); | |
773 | goto out_free_config; | |
774 | } | |
e9be9d5e | 775 | |
53a08cb9 MS |
776 | err = ovl_mount_dir(ufs->config.upperdir, &upperpath); |
777 | if (err) | |
778 | goto out_free_config; | |
e9be9d5e | 779 | |
71cbad7e | 780 | /* Upper fs should not be r/o */ |
781 | if (upperpath.mnt->mnt_sb->s_flags & MS_RDONLY) { | |
782 | pr_err("overlayfs: upper fs is r/o, try multi-lower layers mount\n"); | |
783 | err = -EINVAL; | |
784 | goto out_put_upperpath; | |
785 | } | |
786 | ||
6b2d5fe4 MS |
787 | err = ovl_check_namelen(&upperpath, ufs, ufs->config.upperdir); |
788 | if (err) | |
789 | goto out_put_upperpath; | |
790 | ||
53a08cb9 MS |
791 | err = ovl_mount_dir(ufs->config.workdir, &workpath); |
792 | if (err) | |
793 | goto out_put_upperpath; | |
794 | ||
2f83fd8c | 795 | err = -EINVAL; |
53a08cb9 MS |
796 | if (upperpath.mnt != workpath.mnt) { |
797 | pr_err("overlayfs: workdir and upperdir must reside under the same mount\n"); | |
798 | goto out_put_workpath; | |
799 | } | |
800 | if (!ovl_workdir_ok(workpath.dentry, upperpath.dentry)) { | |
801 | pr_err("overlayfs: workdir and upperdir must be separate subtrees\n"); | |
802 | goto out_put_workpath; | |
803 | } | |
804 | sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth; | |
cc259639 | 805 | } |
a78d9f0d MS |
806 | err = -ENOMEM; |
807 | lowertmp = kstrdup(ufs->config.lowerdir, GFP_KERNEL); | |
808 | if (!lowertmp) | |
ab508822 | 809 | goto out_put_workpath; |
69c433ed | 810 | |
a78d9f0d MS |
811 | err = -EINVAL; |
812 | stacklen = ovl_split_lowerdirs(lowertmp); | |
6be4506e | 813 | if (stacklen > OVL_MAX_STACK) { |
fd36570a | 814 | pr_err("overlayfs: too many lower directories, limit is %d\n", |
6be4506e | 815 | OVL_MAX_STACK); |
a78d9f0d | 816 | goto out_free_lowertmp; |
6be4506e | 817 | } else if (!ufs->config.upperdir && stacklen == 1) { |
818 | pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n"); | |
819 | goto out_free_lowertmp; | |
820 | } | |
a78d9f0d | 821 | |
313684c4 | 822 | err = -ENOMEM; |
a78d9f0d MS |
823 | stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL); |
824 | if (!stack) | |
825 | goto out_free_lowertmp; | |
826 | ||
313684c4 | 827 | err = -EINVAL; |
a78d9f0d MS |
828 | lower = lowertmp; |
829 | for (numlower = 0; numlower < stacklen; numlower++) { | |
6b2d5fe4 MS |
830 | err = ovl_lower_dir(lower, &stack[numlower], ufs, |
831 | &sb->s_stack_depth, &remote); | |
a78d9f0d MS |
832 | if (err) |
833 | goto out_put_lowerpath; | |
834 | ||
835 | lower = strchr(lower, '\0') + 1; | |
836 | } | |
837 | ||
69c433ed | 838 | err = -EINVAL; |
ab508822 | 839 | sb->s_stack_depth++; |
69c433ed MS |
840 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { |
841 | pr_err("overlayfs: maximum fs stacking depth exceeded\n"); | |
3b7a9a24 | 842 | goto out_put_lowerpath; |
69c433ed MS |
843 | } |
844 | ||
53a08cb9 MS |
845 | if (ufs->config.upperdir) { |
846 | ufs->upper_mnt = clone_private_mount(&upperpath); | |
847 | err = PTR_ERR(ufs->upper_mnt); | |
848 | if (IS_ERR(ufs->upper_mnt)) { | |
849 | pr_err("overlayfs: failed to clone upperpath\n"); | |
850 | goto out_put_lowerpath; | |
851 | } | |
d719e8f2 MS |
852 | /* Don't inherit atime flags */ |
853 | ufs->upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); | |
854 | ||
855 | sb->s_time_gran = ufs->upper_mnt->mnt_sb->s_time_gran; | |
3b7a9a24 | 856 | |
53a08cb9 MS |
857 | ufs->workdir = ovl_workdir_create(ufs->upper_mnt, workpath.dentry); |
858 | err = PTR_ERR(ufs->workdir); | |
859 | if (IS_ERR(ufs->workdir)) { | |
cc6f67bc MS |
860 | pr_warn("overlayfs: failed to create directory %s/%s (errno: %i); mounting read-only\n", |
861 | ufs->config.workdir, OVL_WORKDIR_NAME, -err); | |
862 | sb->s_flags |= MS_RDONLY; | |
863 | ufs->workdir = NULL; | |
53a08cb9 | 864 | } |
45aebeaf VG |
865 | |
866 | /* | |
867 | * Upper should support d_type, else whiteouts are visible. | |
868 | * Given workdir and upper are on same fs, we can do | |
21765194 VG |
869 | * iterate_dir() on workdir. This check requires successful |
870 | * creation of workdir in previous step. | |
45aebeaf | 871 | */ |
21765194 | 872 | if (ufs->workdir) { |
e7f52429 AG |
873 | struct dentry *temp; |
874 | ||
21765194 VG |
875 | err = ovl_check_d_type_supported(&workpath); |
876 | if (err < 0) | |
877 | goto out_put_workdir; | |
45aebeaf | 878 | |
e7c0b599 VG |
879 | /* |
880 | * We allowed this configuration and don't want to | |
881 | * break users over kernel upgrade. So warn instead | |
882 | * of erroring out. | |
883 | */ | |
884 | if (!err) | |
885 | pr_warn("overlayfs: upper fs needs to support d_type.\n"); | |
e7f52429 AG |
886 | |
887 | /* Check if upper/work fs supports O_TMPFILE */ | |
888 | temp = ovl_do_tmpfile(ufs->workdir, S_IFREG | 0); | |
889 | ufs->tmpfile = !IS_ERR(temp); | |
890 | if (ufs->tmpfile) | |
891 | dput(temp); | |
892 | else | |
893 | pr_warn("overlayfs: upper fs does not support tmpfile.\n"); | |
82b749b2 AG |
894 | |
895 | /* | |
896 | * Check if upper/work fs supports trusted.overlay.* | |
897 | * xattr | |
898 | */ | |
899 | err = ovl_do_setxattr(ufs->workdir, OVL_XATTR_OPAQUE, | |
900 | "0", 1, 0); | |
901 | if (err) { | |
902 | ufs->noxattr = true; | |
903 | pr_warn("overlayfs: upper fs does not support xattr.\n"); | |
904 | } else { | |
905 | vfs_removexattr(ufs->workdir, OVL_XATTR_OPAQUE); | |
906 | } | |
45aebeaf | 907 | } |
e9be9d5e MS |
908 | } |
909 | ||
2f83fd8c | 910 | err = -ENOMEM; |
a78d9f0d | 911 | ufs->lower_mnt = kcalloc(numlower, sizeof(struct vfsmount *), GFP_KERNEL); |
dd662667 | 912 | if (ufs->lower_mnt == NULL) |
3b7a9a24 | 913 | goto out_put_workdir; |
a78d9f0d MS |
914 | for (i = 0; i < numlower; i++) { |
915 | struct vfsmount *mnt = clone_private_mount(&stack[i]); | |
dd662667 | 916 | |
2f83fd8c | 917 | err = PTR_ERR(mnt); |
a78d9f0d MS |
918 | if (IS_ERR(mnt)) { |
919 | pr_err("overlayfs: failed to clone lowerpath\n"); | |
920 | goto out_put_lower_mnt; | |
921 | } | |
922 | /* | |
923 | * Make lower_mnt R/O. That way fchmod/fchown on lower file | |
924 | * will fail instead of modifying lower fs. | |
925 | */ | |
d719e8f2 | 926 | mnt->mnt_flags |= MNT_READONLY | MNT_NOATIME; |
dd662667 | 927 | |
a78d9f0d MS |
928 | ufs->lower_mnt[ufs->numlower] = mnt; |
929 | ufs->numlower++; | |
7bcd74b9 AG |
930 | |
931 | /* Check if all lower layers are on same sb */ | |
932 | if (i == 0) | |
933 | ufs->same_sb = mnt->mnt_sb; | |
934 | else if (ufs->same_sb != mnt->mnt_sb) | |
935 | ufs->same_sb = NULL; | |
a78d9f0d | 936 | } |
e9be9d5e | 937 | |
71cbad7e | 938 | /* If the upper fs is nonexistent, we mark overlayfs r/o too */ |
939 | if (!ufs->upper_mnt) | |
e9be9d5e | 940 | sb->s_flags |= MS_RDONLY; |
7bcd74b9 AG |
941 | else if (ufs->upper_mnt->mnt_sb != ufs->same_sb) |
942 | ufs->same_sb = NULL; | |
e9be9d5e | 943 | |
7c03b5d4 MS |
944 | if (remote) |
945 | sb->s_d_op = &ovl_reval_dentry_operations; | |
946 | else | |
947 | sb->s_d_op = &ovl_dentry_operations; | |
e9be9d5e | 948 | |
51f8f3c4 KK |
949 | ufs->creator_cred = cred = prepare_creds(); |
950 | if (!cred) | |
3fe6e52f AM |
951 | goto out_put_lower_mnt; |
952 | ||
51f8f3c4 KK |
953 | /* Never override disk quota limits or use reserved space */ |
954 | cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); | |
955 | ||
e9be9d5e | 956 | err = -ENOMEM; |
a78d9f0d | 957 | oe = ovl_alloc_entry(numlower); |
3b7a9a24 | 958 | if (!oe) |
3fe6e52f | 959 | goto out_put_cred; |
e9be9d5e | 960 | |
655042cc VG |
961 | sb->s_magic = OVERLAYFS_SUPER_MAGIC; |
962 | sb->s_op = &ovl_super_operations; | |
963 | sb->s_xattr = ovl_xattr_handlers; | |
964 | sb->s_fs_info = ufs; | |
965 | sb->s_flags |= MS_POSIXACL | MS_NOREMOTELOCK; | |
966 | ||
ca4c8a3a | 967 | root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); |
e9be9d5e | 968 | if (!root_dentry) |
3b7a9a24 | 969 | goto out_free_oe; |
e9be9d5e MS |
970 | |
971 | mntput(upperpath.mnt); | |
a78d9f0d MS |
972 | for (i = 0; i < numlower; i++) |
973 | mntput(stack[i].mnt); | |
e9be9d5e | 974 | path_put(&workpath); |
a78d9f0d | 975 | kfree(lowertmp); |
e9be9d5e | 976 | |
f3a15685 AG |
977 | if (upperpath.dentry) { |
978 | oe->__upperdentry = upperpath.dentry; | |
979 | oe->impure = ovl_is_impuredir(upperpath.dentry); | |
980 | } | |
a78d9f0d MS |
981 | for (i = 0; i < numlower; i++) { |
982 | oe->lowerstack[i].dentry = stack[i].dentry; | |
983 | oe->lowerstack[i].mnt = ufs->lower_mnt[i]; | |
984 | } | |
0f95502a | 985 | kfree(stack); |
e9be9d5e MS |
986 | |
987 | root_dentry->d_fsdata = oe; | |
988 | ||
39b681f8 MS |
989 | realinode = d_inode(ovl_dentry_real(root_dentry)); |
990 | ovl_inode_init(d_inode(root_dentry), realinode, !!upperpath.dentry); | |
991 | ovl_copyattr(realinode, d_inode(root_dentry)); | |
ed06e069 | 992 | |
e9be9d5e | 993 | sb->s_root = root_dentry; |
e9be9d5e MS |
994 | |
995 | return 0; | |
996 | ||
3b7a9a24 MS |
997 | out_free_oe: |
998 | kfree(oe); | |
3fe6e52f AM |
999 | out_put_cred: |
1000 | put_cred(ufs->creator_cred); | |
e9be9d5e | 1001 | out_put_lower_mnt: |
dd662667 MS |
1002 | for (i = 0; i < ufs->numlower; i++) |
1003 | mntput(ufs->lower_mnt[i]); | |
1004 | kfree(ufs->lower_mnt); | |
3b7a9a24 MS |
1005 | out_put_workdir: |
1006 | dput(ufs->workdir); | |
e9be9d5e | 1007 | mntput(ufs->upper_mnt); |
e9be9d5e | 1008 | out_put_lowerpath: |
a78d9f0d MS |
1009 | for (i = 0; i < numlower; i++) |
1010 | path_put(&stack[i]); | |
1011 | kfree(stack); | |
1012 | out_free_lowertmp: | |
1013 | kfree(lowertmp); | |
3b7a9a24 MS |
1014 | out_put_workpath: |
1015 | path_put(&workpath); | |
e9be9d5e MS |
1016 | out_put_upperpath: |
1017 | path_put(&upperpath); | |
e9be9d5e | 1018 | out_free_config: |
f45827e8 EZ |
1019 | kfree(ufs->config.lowerdir); |
1020 | kfree(ufs->config.upperdir); | |
1021 | kfree(ufs->config.workdir); | |
1022 | kfree(ufs); | |
e9be9d5e MS |
1023 | out: |
1024 | return err; | |
1025 | } | |
1026 | ||
1027 | static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, | |
1028 | const char *dev_name, void *raw_data) | |
1029 | { | |
1030 | return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); | |
1031 | } | |
1032 | ||
1033 | static struct file_system_type ovl_fs_type = { | |
1034 | .owner = THIS_MODULE, | |
ef94b186 | 1035 | .name = "overlay", |
e9be9d5e MS |
1036 | .mount = ovl_mount, |
1037 | .kill_sb = kill_anon_super, | |
1038 | }; | |
ef94b186 | 1039 | MODULE_ALIAS_FS("overlay"); |
e9be9d5e MS |
1040 | |
1041 | static int __init ovl_init(void) | |
1042 | { | |
1043 | return register_filesystem(&ovl_fs_type); | |
1044 | } | |
1045 | ||
1046 | static void __exit ovl_exit(void) | |
1047 | { | |
1048 | unregister_filesystem(&ovl_fs_type); | |
1049 | } | |
1050 | ||
1051 | module_init(ovl_init); | |
1052 | module_exit(ovl_exit); |