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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 | ||
10 | #include <linux/fs.h> | |
11 | #include <linux/namei.h> | |
12 | #include <linux/xattr.h> | |
13 | #include <linux/security.h> | |
14 | #include <linux/mount.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/parser.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/sched.h> | |
cc259639 | 19 | #include <linux/statfs.h> |
f45827e8 | 20 | #include <linux/seq_file.h> |
e9be9d5e MS |
21 | #include "overlayfs.h" |
22 | ||
23 | MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); | |
24 | MODULE_DESCRIPTION("Overlay filesystem"); | |
25 | MODULE_LICENSE("GPL"); | |
26 | ||
f45827e8 EZ |
27 | struct ovl_config { |
28 | char *lowerdir; | |
29 | char *upperdir; | |
30 | char *workdir; | |
8d3095f4 | 31 | bool default_permissions; |
f45827e8 EZ |
32 | }; |
33 | ||
e9be9d5e MS |
34 | /* private information held for overlayfs's superblock */ |
35 | struct ovl_fs { | |
36 | struct vfsmount *upper_mnt; | |
dd662667 MS |
37 | unsigned numlower; |
38 | struct vfsmount **lower_mnt; | |
e9be9d5e | 39 | struct dentry *workdir; |
cc259639 | 40 | long lower_namelen; |
f45827e8 EZ |
41 | /* pathnames of lower and upper dirs, for show_options */ |
42 | struct ovl_config config; | |
e9be9d5e MS |
43 | }; |
44 | ||
45 | struct ovl_dir_cache; | |
46 | ||
47 | /* private information held for every overlayfs dentry */ | |
48 | struct ovl_entry { | |
49 | struct dentry *__upperdentry; | |
e9be9d5e MS |
50 | struct ovl_dir_cache *cache; |
51 | union { | |
52 | struct { | |
53 | u64 version; | |
54 | bool opaque; | |
55 | }; | |
56 | struct rcu_head rcu; | |
57 | }; | |
dd662667 MS |
58 | unsigned numlower; |
59 | struct path lowerstack[]; | |
e9be9d5e MS |
60 | }; |
61 | ||
a78d9f0d MS |
62 | #define OVL_MAX_STACK 500 |
63 | ||
dd662667 MS |
64 | static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe) |
65 | { | |
66 | return oe->numlower ? oe->lowerstack[0].dentry : NULL; | |
67 | } | |
e9be9d5e MS |
68 | |
69 | enum ovl_path_type ovl_path_type(struct dentry *dentry) | |
70 | { | |
71 | struct ovl_entry *oe = dentry->d_fsdata; | |
1afaba1e | 72 | enum ovl_path_type type = 0; |
e9be9d5e MS |
73 | |
74 | if (oe->__upperdentry) { | |
1afaba1e MS |
75 | type = __OVL_PATH_UPPER; |
76 | ||
dd662667 | 77 | if (oe->numlower) { |
e9be9d5e | 78 | if (S_ISDIR(dentry->d_inode->i_mode)) |
1afaba1e MS |
79 | type |= __OVL_PATH_MERGE; |
80 | } else if (!oe->opaque) { | |
81 | type |= __OVL_PATH_PURE; | |
e9be9d5e | 82 | } |
9d7459d8 MS |
83 | } else { |
84 | if (oe->numlower > 1) | |
85 | type |= __OVL_PATH_MERGE; | |
e9be9d5e | 86 | } |
1afaba1e | 87 | return type; |
e9be9d5e MS |
88 | } |
89 | ||
90 | static struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe) | |
91 | { | |
71d50928 | 92 | return lockless_dereference(oe->__upperdentry); |
e9be9d5e MS |
93 | } |
94 | ||
95 | void ovl_path_upper(struct dentry *dentry, struct path *path) | |
96 | { | |
97 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
98 | struct ovl_entry *oe = dentry->d_fsdata; | |
99 | ||
100 | path->mnt = ofs->upper_mnt; | |
101 | path->dentry = ovl_upperdentry_dereference(oe); | |
102 | } | |
103 | ||
104 | enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path) | |
105 | { | |
e9be9d5e MS |
106 | enum ovl_path_type type = ovl_path_type(dentry); |
107 | ||
1afaba1e | 108 | if (!OVL_TYPE_UPPER(type)) |
e9be9d5e MS |
109 | ovl_path_lower(dentry, path); |
110 | else | |
111 | ovl_path_upper(dentry, path); | |
112 | ||
113 | return type; | |
114 | } | |
115 | ||
116 | struct dentry *ovl_dentry_upper(struct dentry *dentry) | |
117 | { | |
118 | struct ovl_entry *oe = dentry->d_fsdata; | |
119 | ||
120 | return ovl_upperdentry_dereference(oe); | |
121 | } | |
122 | ||
123 | struct dentry *ovl_dentry_lower(struct dentry *dentry) | |
124 | { | |
125 | struct ovl_entry *oe = dentry->d_fsdata; | |
126 | ||
dd662667 | 127 | return __ovl_dentry_lower(oe); |
e9be9d5e MS |
128 | } |
129 | ||
130 | struct dentry *ovl_dentry_real(struct dentry *dentry) | |
131 | { | |
132 | struct ovl_entry *oe = dentry->d_fsdata; | |
133 | struct dentry *realdentry; | |
134 | ||
135 | realdentry = ovl_upperdentry_dereference(oe); | |
136 | if (!realdentry) | |
dd662667 | 137 | realdentry = __ovl_dentry_lower(oe); |
e9be9d5e MS |
138 | |
139 | return realdentry; | |
140 | } | |
141 | ||
142 | struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper) | |
143 | { | |
144 | struct dentry *realdentry; | |
145 | ||
146 | realdentry = ovl_upperdentry_dereference(oe); | |
147 | if (realdentry) { | |
148 | *is_upper = true; | |
149 | } else { | |
dd662667 | 150 | realdentry = __ovl_dentry_lower(oe); |
e9be9d5e MS |
151 | *is_upper = false; |
152 | } | |
153 | return realdentry; | |
154 | } | |
155 | ||
8d3095f4 MS |
156 | struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode, |
157 | bool is_upper) | |
158 | { | |
159 | if (is_upper) { | |
160 | struct ovl_fs *ofs = inode->i_sb->s_fs_info; | |
161 | ||
162 | return ofs->upper_mnt; | |
163 | } else { | |
164 | return oe->numlower ? oe->lowerstack[0].mnt : NULL; | |
165 | } | |
166 | } | |
167 | ||
e9be9d5e MS |
168 | struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry) |
169 | { | |
170 | struct ovl_entry *oe = dentry->d_fsdata; | |
171 | ||
172 | return oe->cache; | |
173 | } | |
174 | ||
8d3095f4 MS |
175 | bool ovl_is_default_permissions(struct inode *inode) |
176 | { | |
177 | struct ovl_fs *ofs = inode->i_sb->s_fs_info; | |
178 | ||
179 | return ofs->config.default_permissions; | |
180 | } | |
181 | ||
e9be9d5e MS |
182 | void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache) |
183 | { | |
184 | struct ovl_entry *oe = dentry->d_fsdata; | |
185 | ||
186 | oe->cache = cache; | |
187 | } | |
188 | ||
189 | void ovl_path_lower(struct dentry *dentry, struct path *path) | |
190 | { | |
e9be9d5e MS |
191 | struct ovl_entry *oe = dentry->d_fsdata; |
192 | ||
dd662667 | 193 | *path = oe->numlower ? oe->lowerstack[0] : (struct path) { NULL, NULL }; |
e9be9d5e MS |
194 | } |
195 | ||
196 | int ovl_want_write(struct dentry *dentry) | |
197 | { | |
198 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
199 | return mnt_want_write(ofs->upper_mnt); | |
200 | } | |
201 | ||
202 | void ovl_drop_write(struct dentry *dentry) | |
203 | { | |
204 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
205 | mnt_drop_write(ofs->upper_mnt); | |
206 | } | |
207 | ||
208 | struct dentry *ovl_workdir(struct dentry *dentry) | |
209 | { | |
210 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
211 | return ofs->workdir; | |
212 | } | |
213 | ||
214 | bool ovl_dentry_is_opaque(struct dentry *dentry) | |
215 | { | |
216 | struct ovl_entry *oe = dentry->d_fsdata; | |
217 | return oe->opaque; | |
218 | } | |
219 | ||
220 | void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque) | |
221 | { | |
222 | struct ovl_entry *oe = dentry->d_fsdata; | |
223 | oe->opaque = opaque; | |
224 | } | |
225 | ||
226 | void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry) | |
227 | { | |
228 | struct ovl_entry *oe = dentry->d_fsdata; | |
229 | ||
230 | WARN_ON(!mutex_is_locked(&upperdentry->d_parent->d_inode->i_mutex)); | |
231 | WARN_ON(oe->__upperdentry); | |
232 | BUG_ON(!upperdentry->d_inode); | |
233 | /* | |
234 | * Make sure upperdentry is consistent before making it visible to | |
235 | * ovl_upperdentry_dereference(). | |
236 | */ | |
237 | smp_wmb(); | |
238 | oe->__upperdentry = upperdentry; | |
239 | } | |
240 | ||
241 | void ovl_dentry_version_inc(struct dentry *dentry) | |
242 | { | |
243 | struct ovl_entry *oe = dentry->d_fsdata; | |
244 | ||
245 | WARN_ON(!mutex_is_locked(&dentry->d_inode->i_mutex)); | |
246 | oe->version++; | |
247 | } | |
248 | ||
249 | u64 ovl_dentry_version_get(struct dentry *dentry) | |
250 | { | |
251 | struct ovl_entry *oe = dentry->d_fsdata; | |
252 | ||
253 | WARN_ON(!mutex_is_locked(&dentry->d_inode->i_mutex)); | |
254 | return oe->version; | |
255 | } | |
256 | ||
257 | bool ovl_is_whiteout(struct dentry *dentry) | |
258 | { | |
259 | struct inode *inode = dentry->d_inode; | |
260 | ||
261 | return inode && IS_WHITEOUT(inode); | |
262 | } | |
263 | ||
264 | static bool ovl_is_opaquedir(struct dentry *dentry) | |
265 | { | |
266 | int res; | |
267 | char val; | |
268 | struct inode *inode = dentry->d_inode; | |
269 | ||
270 | if (!S_ISDIR(inode->i_mode) || !inode->i_op->getxattr) | |
271 | return false; | |
272 | ||
cead89bb | 273 | res = inode->i_op->getxattr(dentry, OVL_XATTR_OPAQUE, &val, 1); |
e9be9d5e MS |
274 | if (res == 1 && val == 'y') |
275 | return true; | |
276 | ||
277 | return false; | |
278 | } | |
279 | ||
280 | static void ovl_dentry_release(struct dentry *dentry) | |
281 | { | |
282 | struct ovl_entry *oe = dentry->d_fsdata; | |
283 | ||
284 | if (oe) { | |
dd662667 MS |
285 | unsigned int i; |
286 | ||
e9be9d5e | 287 | dput(oe->__upperdentry); |
dd662667 MS |
288 | for (i = 0; i < oe->numlower; i++) |
289 | dput(oe->lowerstack[i].dentry); | |
e9be9d5e MS |
290 | kfree_rcu(oe, rcu); |
291 | } | |
292 | } | |
293 | ||
7c03b5d4 MS |
294 | static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
295 | { | |
296 | struct ovl_entry *oe = dentry->d_fsdata; | |
297 | unsigned int i; | |
298 | int ret = 1; | |
299 | ||
300 | for (i = 0; i < oe->numlower; i++) { | |
301 | struct dentry *d = oe->lowerstack[i].dentry; | |
302 | ||
303 | if (d->d_flags & DCACHE_OP_REVALIDATE) { | |
304 | ret = d->d_op->d_revalidate(d, flags); | |
305 | if (ret < 0) | |
306 | return ret; | |
307 | if (!ret) { | |
308 | if (!(flags & LOOKUP_RCU)) | |
309 | d_invalidate(d); | |
310 | return -ESTALE; | |
311 | } | |
312 | } | |
313 | } | |
314 | return 1; | |
315 | } | |
316 | ||
317 | static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) | |
318 | { | |
319 | struct ovl_entry *oe = dentry->d_fsdata; | |
320 | unsigned int i; | |
321 | int ret = 1; | |
322 | ||
323 | for (i = 0; i < oe->numlower; i++) { | |
324 | struct dentry *d = oe->lowerstack[i].dentry; | |
325 | ||
326 | if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) { | |
327 | ret = d->d_op->d_weak_revalidate(d, flags); | |
328 | if (ret <= 0) | |
329 | break; | |
330 | } | |
331 | } | |
332 | return ret; | |
333 | } | |
334 | ||
e9be9d5e MS |
335 | static const struct dentry_operations ovl_dentry_operations = { |
336 | .d_release = ovl_dentry_release, | |
4bacc9c9 | 337 | .d_select_inode = ovl_d_select_inode, |
e9be9d5e MS |
338 | }; |
339 | ||
7c03b5d4 MS |
340 | static const struct dentry_operations ovl_reval_dentry_operations = { |
341 | .d_release = ovl_dentry_release, | |
342 | .d_revalidate = ovl_dentry_revalidate, | |
343 | .d_weak_revalidate = ovl_dentry_weak_revalidate, | |
344 | }; | |
345 | ||
dd662667 | 346 | static struct ovl_entry *ovl_alloc_entry(unsigned int numlower) |
e9be9d5e | 347 | { |
dd662667 MS |
348 | size_t size = offsetof(struct ovl_entry, lowerstack[numlower]); |
349 | struct ovl_entry *oe = kzalloc(size, GFP_KERNEL); | |
350 | ||
351 | if (oe) | |
352 | oe->numlower = numlower; | |
353 | ||
354 | return oe; | |
e9be9d5e MS |
355 | } |
356 | ||
7c03b5d4 MS |
357 | static bool ovl_dentry_remote(struct dentry *dentry) |
358 | { | |
359 | return dentry->d_flags & | |
360 | (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE); | |
361 | } | |
362 | ||
363 | static bool ovl_dentry_weird(struct dentry *dentry) | |
364 | { | |
365 | return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT | | |
366 | DCACHE_MANAGE_TRANSIT | | |
367 | DCACHE_OP_HASH | | |
368 | DCACHE_OP_COMPARE); | |
369 | } | |
370 | ||
e9be9d5e MS |
371 | static inline struct dentry *ovl_lookup_real(struct dentry *dir, |
372 | struct qstr *name) | |
373 | { | |
374 | struct dentry *dentry; | |
375 | ||
376 | mutex_lock(&dir->d_inode->i_mutex); | |
377 | dentry = lookup_one_len(name->name, dir, name->len); | |
378 | mutex_unlock(&dir->d_inode->i_mutex); | |
379 | ||
380 | if (IS_ERR(dentry)) { | |
381 | if (PTR_ERR(dentry) == -ENOENT) | |
382 | dentry = NULL; | |
383 | } else if (!dentry->d_inode) { | |
384 | dput(dentry); | |
385 | dentry = NULL; | |
7c03b5d4 | 386 | } else if (ovl_dentry_weird(dentry)) { |
a6f15d9a | 387 | dput(dentry); |
7c03b5d4 | 388 | /* Don't support traversing automounts and other weirdness */ |
a6f15d9a | 389 | dentry = ERR_PTR(-EREMOTE); |
e9be9d5e MS |
390 | } |
391 | return dentry; | |
392 | } | |
393 | ||
5ef88da5 MS |
394 | /* |
395 | * Returns next layer in stack starting from top. | |
396 | * Returns -1 if this is the last layer. | |
397 | */ | |
398 | int ovl_path_next(int idx, struct dentry *dentry, struct path *path) | |
399 | { | |
400 | struct ovl_entry *oe = dentry->d_fsdata; | |
401 | ||
402 | BUG_ON(idx < 0); | |
403 | if (idx == 0) { | |
404 | ovl_path_upper(dentry, path); | |
405 | if (path->dentry) | |
406 | return oe->numlower ? 1 : -1; | |
407 | idx++; | |
408 | } | |
409 | BUG_ON(idx > oe->numlower); | |
410 | *path = oe->lowerstack[idx - 1]; | |
411 | ||
412 | return (idx < oe->numlower) ? idx + 1 : -1; | |
413 | } | |
414 | ||
e9be9d5e MS |
415 | struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, |
416 | unsigned int flags) | |
417 | { | |
418 | struct ovl_entry *oe; | |
3d3c6b89 MS |
419 | struct ovl_entry *poe = dentry->d_parent->d_fsdata; |
420 | struct path *stack = NULL; | |
421 | struct dentry *upperdir, *upperdentry = NULL; | |
422 | unsigned int ctr = 0; | |
e9be9d5e | 423 | struct inode *inode = NULL; |
3d3c6b89 MS |
424 | bool upperopaque = false; |
425 | struct dentry *this, *prev = NULL; | |
426 | unsigned int i; | |
e9be9d5e MS |
427 | int err; |
428 | ||
3d3c6b89 | 429 | upperdir = ovl_upperdentry_dereference(poe); |
e9be9d5e | 430 | if (upperdir) { |
3d3c6b89 MS |
431 | this = ovl_lookup_real(upperdir, &dentry->d_name); |
432 | err = PTR_ERR(this); | |
433 | if (IS_ERR(this)) | |
434 | goto out; | |
435 | ||
3e01cee3 | 436 | if (this) { |
7c03b5d4 MS |
437 | if (unlikely(ovl_dentry_remote(this))) { |
438 | dput(this); | |
439 | err = -EREMOTE; | |
440 | goto out; | |
441 | } | |
3d3c6b89 MS |
442 | if (ovl_is_whiteout(this)) { |
443 | dput(this); | |
444 | this = NULL; | |
445 | upperopaque = true; | |
3e01cee3 | 446 | } else if (poe->numlower && ovl_is_opaquedir(this)) { |
3d3c6b89 | 447 | upperopaque = true; |
e9be9d5e MS |
448 | } |
449 | } | |
3d3c6b89 | 450 | upperdentry = prev = this; |
e9be9d5e | 451 | } |
3d3c6b89 MS |
452 | |
453 | if (!upperopaque && poe->numlower) { | |
454 | err = -ENOMEM; | |
455 | stack = kcalloc(poe->numlower, sizeof(struct path), GFP_KERNEL); | |
456 | if (!stack) | |
457 | goto out_put_upper; | |
e9be9d5e MS |
458 | } |
459 | ||
3d3c6b89 MS |
460 | for (i = 0; !upperopaque && i < poe->numlower; i++) { |
461 | bool opaque = false; | |
462 | struct path lowerpath = poe->lowerstack[i]; | |
463 | ||
3d3c6b89 MS |
464 | this = ovl_lookup_real(lowerpath.dentry, &dentry->d_name); |
465 | err = PTR_ERR(this); | |
09e10322 MS |
466 | if (IS_ERR(this)) { |
467 | /* | |
468 | * If it's positive, then treat ENAMETOOLONG as ENOENT. | |
469 | */ | |
470 | if (err == -ENAMETOOLONG && (upperdentry || ctr)) | |
471 | continue; | |
3d3c6b89 | 472 | goto out_put; |
09e10322 | 473 | } |
3d3c6b89 MS |
474 | if (!this) |
475 | continue; | |
3e01cee3 MS |
476 | if (ovl_is_whiteout(this)) { |
477 | dput(this); | |
478 | break; | |
479 | } | |
3d3c6b89 | 480 | /* |
3e01cee3 MS |
481 | * Only makes sense to check opaque dir if this is not the |
482 | * lowermost layer. | |
3d3c6b89 | 483 | */ |
3e01cee3 MS |
484 | if (i < poe->numlower - 1 && ovl_is_opaquedir(this)) |
485 | opaque = true; | |
a425c037 | 486 | |
487 | if (prev && (!S_ISDIR(prev->d_inode->i_mode) || | |
488 | !S_ISDIR(this->d_inode->i_mode))) { | |
489 | /* | |
490 | * FIXME: check for upper-opaqueness maybe better done | |
491 | * in remove code. | |
492 | */ | |
3d3c6b89 MS |
493 | if (prev == upperdentry) |
494 | upperopaque = true; | |
495 | dput(this); | |
496 | break; | |
497 | } | |
a425c037 | 498 | /* |
499 | * If this is a non-directory then stop here. | |
500 | */ | |
501 | if (!S_ISDIR(this->d_inode->i_mode)) | |
502 | opaque = true; | |
503 | ||
3d3c6b89 MS |
504 | stack[ctr].dentry = this; |
505 | stack[ctr].mnt = lowerpath.mnt; | |
506 | ctr++; | |
507 | prev = this; | |
508 | if (opaque) | |
509 | break; | |
e9be9d5e MS |
510 | } |
511 | ||
3d3c6b89 MS |
512 | oe = ovl_alloc_entry(ctr); |
513 | err = -ENOMEM; | |
514 | if (!oe) | |
515 | goto out_put; | |
516 | ||
517 | if (upperdentry || ctr) { | |
e9be9d5e MS |
518 | struct dentry *realdentry; |
519 | ||
3d3c6b89 MS |
520 | realdentry = upperdentry ? upperdentry : stack[0].dentry; |
521 | ||
e9be9d5e MS |
522 | err = -ENOMEM; |
523 | inode = ovl_new_inode(dentry->d_sb, realdentry->d_inode->i_mode, | |
524 | oe); | |
525 | if (!inode) | |
3d3c6b89 | 526 | goto out_free_oe; |
e9be9d5e MS |
527 | ovl_copyattr(realdentry->d_inode, inode); |
528 | } | |
529 | ||
3d3c6b89 | 530 | oe->opaque = upperopaque; |
e9be9d5e | 531 | oe->__upperdentry = upperdentry; |
3d3c6b89 MS |
532 | memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr); |
533 | kfree(stack); | |
e9be9d5e MS |
534 | dentry->d_fsdata = oe; |
535 | d_add(dentry, inode); | |
536 | ||
537 | return NULL; | |
538 | ||
3d3c6b89 | 539 | out_free_oe: |
e9be9d5e | 540 | kfree(oe); |
3d3c6b89 MS |
541 | out_put: |
542 | for (i = 0; i < ctr; i++) | |
543 | dput(stack[i].dentry); | |
544 | kfree(stack); | |
545 | out_put_upper: | |
546 | dput(upperdentry); | |
e9be9d5e MS |
547 | out: |
548 | return ERR_PTR(err); | |
549 | } | |
550 | ||
551 | struct file *ovl_path_open(struct path *path, int flags) | |
552 | { | |
553 | return dentry_open(path, flags, current_cred()); | |
554 | } | |
555 | ||
556 | static void ovl_put_super(struct super_block *sb) | |
557 | { | |
558 | struct ovl_fs *ufs = sb->s_fs_info; | |
dd662667 | 559 | unsigned i; |
e9be9d5e MS |
560 | |
561 | dput(ufs->workdir); | |
562 | mntput(ufs->upper_mnt); | |
dd662667 MS |
563 | for (i = 0; i < ufs->numlower; i++) |
564 | mntput(ufs->lower_mnt[i]); | |
5ffdbe8b | 565 | kfree(ufs->lower_mnt); |
e9be9d5e | 566 | |
f45827e8 EZ |
567 | kfree(ufs->config.lowerdir); |
568 | kfree(ufs->config.upperdir); | |
569 | kfree(ufs->config.workdir); | |
e9be9d5e MS |
570 | kfree(ufs); |
571 | } | |
572 | ||
cc259639 AW |
573 | /** |
574 | * ovl_statfs | |
575 | * @sb: The overlayfs super block | |
576 | * @buf: The struct kstatfs to fill in with stats | |
577 | * | |
578 | * Get the filesystem statistics. As writes always target the upper layer | |
4ebc5818 | 579 | * filesystem pass the statfs to the upper filesystem (if it exists) |
cc259639 AW |
580 | */ |
581 | static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) | |
582 | { | |
583 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
584 | struct dentry *root_dentry = dentry->d_sb->s_root; | |
585 | struct path path; | |
586 | int err; | |
587 | ||
4ebc5818 | 588 | ovl_path_real(root_dentry, &path); |
cc259639 AW |
589 | |
590 | err = vfs_statfs(&path, buf); | |
591 | if (!err) { | |
592 | buf->f_namelen = max(buf->f_namelen, ofs->lower_namelen); | |
593 | buf->f_type = OVERLAYFS_SUPER_MAGIC; | |
594 | } | |
595 | ||
596 | return err; | |
597 | } | |
598 | ||
f45827e8 EZ |
599 | /** |
600 | * ovl_show_options | |
601 | * | |
602 | * Prints the mount options for a given superblock. | |
603 | * Returns zero; does not fail. | |
604 | */ | |
605 | static int ovl_show_options(struct seq_file *m, struct dentry *dentry) | |
606 | { | |
607 | struct super_block *sb = dentry->d_sb; | |
608 | struct ovl_fs *ufs = sb->s_fs_info; | |
609 | ||
610 | seq_printf(m, ",lowerdir=%s", ufs->config.lowerdir); | |
53a08cb9 MS |
611 | if (ufs->config.upperdir) { |
612 | seq_printf(m, ",upperdir=%s", ufs->config.upperdir); | |
613 | seq_printf(m, ",workdir=%s", ufs->config.workdir); | |
614 | } | |
8d3095f4 MS |
615 | if (ufs->config.default_permissions) |
616 | seq_puts(m, ",default_permissions"); | |
f45827e8 EZ |
617 | return 0; |
618 | } | |
619 | ||
3cdf6fe9 SL |
620 | static int ovl_remount(struct super_block *sb, int *flags, char *data) |
621 | { | |
622 | struct ovl_fs *ufs = sb->s_fs_info; | |
623 | ||
cc6f67bc | 624 | if (!(*flags & MS_RDONLY) && (!ufs->upper_mnt || !ufs->workdir)) |
3cdf6fe9 SL |
625 | return -EROFS; |
626 | ||
627 | return 0; | |
628 | } | |
629 | ||
e9be9d5e MS |
630 | static const struct super_operations ovl_super_operations = { |
631 | .put_super = ovl_put_super, | |
cc259639 | 632 | .statfs = ovl_statfs, |
f45827e8 | 633 | .show_options = ovl_show_options, |
3cdf6fe9 | 634 | .remount_fs = ovl_remount, |
e9be9d5e MS |
635 | }; |
636 | ||
637 | enum { | |
638 | OPT_LOWERDIR, | |
639 | OPT_UPPERDIR, | |
640 | OPT_WORKDIR, | |
8d3095f4 | 641 | OPT_DEFAULT_PERMISSIONS, |
e9be9d5e MS |
642 | OPT_ERR, |
643 | }; | |
644 | ||
645 | static const match_table_t ovl_tokens = { | |
646 | {OPT_LOWERDIR, "lowerdir=%s"}, | |
647 | {OPT_UPPERDIR, "upperdir=%s"}, | |
648 | {OPT_WORKDIR, "workdir=%s"}, | |
8d3095f4 | 649 | {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, |
e9be9d5e MS |
650 | {OPT_ERR, NULL} |
651 | }; | |
652 | ||
91c77947 MS |
653 | static char *ovl_next_opt(char **s) |
654 | { | |
655 | char *sbegin = *s; | |
656 | char *p; | |
657 | ||
658 | if (sbegin == NULL) | |
659 | return NULL; | |
660 | ||
661 | for (p = sbegin; *p; p++) { | |
662 | if (*p == '\\') { | |
663 | p++; | |
664 | if (!*p) | |
665 | break; | |
666 | } else if (*p == ',') { | |
667 | *p = '\0'; | |
668 | *s = p + 1; | |
669 | return sbegin; | |
670 | } | |
671 | } | |
672 | *s = NULL; | |
673 | return sbegin; | |
674 | } | |
675 | ||
e9be9d5e MS |
676 | static int ovl_parse_opt(char *opt, struct ovl_config *config) |
677 | { | |
678 | char *p; | |
679 | ||
91c77947 | 680 | while ((p = ovl_next_opt(&opt)) != NULL) { |
e9be9d5e MS |
681 | int token; |
682 | substring_t args[MAX_OPT_ARGS]; | |
683 | ||
684 | if (!*p) | |
685 | continue; | |
686 | ||
687 | token = match_token(p, ovl_tokens, args); | |
688 | switch (token) { | |
689 | case OPT_UPPERDIR: | |
690 | kfree(config->upperdir); | |
691 | config->upperdir = match_strdup(&args[0]); | |
692 | if (!config->upperdir) | |
693 | return -ENOMEM; | |
694 | break; | |
695 | ||
696 | case OPT_LOWERDIR: | |
697 | kfree(config->lowerdir); | |
698 | config->lowerdir = match_strdup(&args[0]); | |
699 | if (!config->lowerdir) | |
700 | return -ENOMEM; | |
701 | break; | |
702 | ||
703 | case OPT_WORKDIR: | |
704 | kfree(config->workdir); | |
705 | config->workdir = match_strdup(&args[0]); | |
706 | if (!config->workdir) | |
707 | return -ENOMEM; | |
708 | break; | |
709 | ||
8d3095f4 MS |
710 | case OPT_DEFAULT_PERMISSIONS: |
711 | config->default_permissions = true; | |
712 | break; | |
713 | ||
e9be9d5e | 714 | default: |
bead55ef | 715 | pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p); |
e9be9d5e MS |
716 | return -EINVAL; |
717 | } | |
718 | } | |
71cbad7e | 719 | |
720 | /* Workdir is useless in non-upper mount */ | |
721 | if (!config->upperdir && config->workdir) { | |
722 | pr_info("overlayfs: option \"workdir=%s\" is useless in a non-upper mount, ignore\n", | |
723 | config->workdir); | |
724 | kfree(config->workdir); | |
725 | config->workdir = NULL; | |
726 | } | |
727 | ||
e9be9d5e MS |
728 | return 0; |
729 | } | |
730 | ||
731 | #define OVL_WORKDIR_NAME "work" | |
732 | ||
733 | static struct dentry *ovl_workdir_create(struct vfsmount *mnt, | |
734 | struct dentry *dentry) | |
735 | { | |
736 | struct inode *dir = dentry->d_inode; | |
737 | struct dentry *work; | |
738 | int err; | |
739 | bool retried = false; | |
740 | ||
741 | err = mnt_want_write(mnt); | |
742 | if (err) | |
743 | return ERR_PTR(err); | |
744 | ||
745 | mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT); | |
746 | retry: | |
747 | work = lookup_one_len(OVL_WORKDIR_NAME, dentry, | |
748 | strlen(OVL_WORKDIR_NAME)); | |
749 | ||
750 | if (!IS_ERR(work)) { | |
751 | struct kstat stat = { | |
752 | .mode = S_IFDIR | 0, | |
753 | }; | |
754 | ||
755 | if (work->d_inode) { | |
756 | err = -EEXIST; | |
757 | if (retried) | |
758 | goto out_dput; | |
759 | ||
760 | retried = true; | |
761 | ovl_cleanup(dir, work); | |
762 | dput(work); | |
763 | goto retry; | |
764 | } | |
765 | ||
766 | err = ovl_create_real(dir, work, &stat, NULL, NULL, true); | |
767 | if (err) | |
768 | goto out_dput; | |
769 | } | |
770 | out_unlock: | |
771 | mutex_unlock(&dir->i_mutex); | |
772 | mnt_drop_write(mnt); | |
773 | ||
774 | return work; | |
775 | ||
776 | out_dput: | |
777 | dput(work); | |
778 | work = ERR_PTR(err); | |
779 | goto out_unlock; | |
780 | } | |
781 | ||
91c77947 MS |
782 | static void ovl_unescape(char *s) |
783 | { | |
784 | char *d = s; | |
785 | ||
786 | for (;; s++, d++) { | |
787 | if (*s == '\\') | |
788 | s++; | |
789 | *d = *s; | |
790 | if (!*s) | |
791 | break; | |
792 | } | |
793 | } | |
794 | ||
ab508822 MS |
795 | static int ovl_mount_dir_noesc(const char *name, struct path *path) |
796 | { | |
a78d9f0d | 797 | int err = -EINVAL; |
ab508822 | 798 | |
a78d9f0d MS |
799 | if (!*name) { |
800 | pr_err("overlayfs: empty lowerdir\n"); | |
801 | goto out; | |
802 | } | |
ab508822 MS |
803 | err = kern_path(name, LOOKUP_FOLLOW, path); |
804 | if (err) { | |
805 | pr_err("overlayfs: failed to resolve '%s': %i\n", name, err); | |
806 | goto out; | |
807 | } | |
808 | err = -EINVAL; | |
7c03b5d4 | 809 | if (ovl_dentry_weird(path->dentry)) { |
ab508822 MS |
810 | pr_err("overlayfs: filesystem on '%s' not supported\n", name); |
811 | goto out_put; | |
812 | } | |
813 | if (!S_ISDIR(path->dentry->d_inode->i_mode)) { | |
814 | pr_err("overlayfs: '%s' not a directory\n", name); | |
815 | goto out_put; | |
816 | } | |
817 | return 0; | |
818 | ||
819 | out_put: | |
820 | path_put(path); | |
821 | out: | |
822 | return err; | |
823 | } | |
824 | ||
825 | static int ovl_mount_dir(const char *name, struct path *path) | |
826 | { | |
827 | int err = -ENOMEM; | |
828 | char *tmp = kstrdup(name, GFP_KERNEL); | |
829 | ||
830 | if (tmp) { | |
831 | ovl_unescape(tmp); | |
832 | err = ovl_mount_dir_noesc(tmp, path); | |
7c03b5d4 MS |
833 | |
834 | if (!err) | |
835 | if (ovl_dentry_remote(path->dentry)) { | |
836 | pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n", | |
837 | tmp); | |
838 | path_put(path); | |
839 | err = -EINVAL; | |
840 | } | |
ab508822 MS |
841 | kfree(tmp); |
842 | } | |
843 | return err; | |
844 | } | |
845 | ||
846 | static int ovl_lower_dir(const char *name, struct path *path, long *namelen, | |
7c03b5d4 | 847 | int *stack_depth, bool *remote) |
ab508822 MS |
848 | { |
849 | int err; | |
850 | struct kstatfs statfs; | |
851 | ||
a78d9f0d | 852 | err = ovl_mount_dir_noesc(name, path); |
ab508822 MS |
853 | if (err) |
854 | goto out; | |
855 | ||
856 | err = vfs_statfs(path, &statfs); | |
857 | if (err) { | |
858 | pr_err("overlayfs: statfs failed on '%s'\n", name); | |
859 | goto out_put; | |
860 | } | |
861 | *namelen = max(*namelen, statfs.f_namelen); | |
862 | *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); | |
863 | ||
7c03b5d4 MS |
864 | if (ovl_dentry_remote(path->dentry)) |
865 | *remote = true; | |
866 | ||
ab508822 MS |
867 | return 0; |
868 | ||
869 | out_put: | |
870 | path_put(path); | |
871 | out: | |
872 | return err; | |
873 | } | |
874 | ||
e9be9d5e MS |
875 | /* Workdir should not be subdir of upperdir and vice versa */ |
876 | static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) | |
877 | { | |
878 | bool ok = false; | |
879 | ||
880 | if (workdir != upperdir) { | |
881 | ok = (lock_rename(workdir, upperdir) == NULL); | |
882 | unlock_rename(workdir, upperdir); | |
883 | } | |
884 | return ok; | |
885 | } | |
886 | ||
a78d9f0d MS |
887 | static unsigned int ovl_split_lowerdirs(char *str) |
888 | { | |
889 | unsigned int ctr = 1; | |
890 | char *s, *d; | |
891 | ||
892 | for (s = d = str;; s++, d++) { | |
893 | if (*s == '\\') { | |
894 | s++; | |
895 | } else if (*s == ':') { | |
896 | *d = '\0'; | |
897 | ctr++; | |
898 | continue; | |
899 | } | |
900 | *d = *s; | |
901 | if (!*s) | |
902 | break; | |
903 | } | |
904 | return ctr; | |
905 | } | |
906 | ||
e9be9d5e MS |
907 | static int ovl_fill_super(struct super_block *sb, void *data, int silent) |
908 | { | |
53a08cb9 MS |
909 | struct path upperpath = { NULL, NULL }; |
910 | struct path workpath = { NULL, NULL }; | |
e9be9d5e MS |
911 | struct dentry *root_dentry; |
912 | struct ovl_entry *oe; | |
913 | struct ovl_fs *ufs; | |
a78d9f0d MS |
914 | struct path *stack = NULL; |
915 | char *lowertmp; | |
916 | char *lower; | |
917 | unsigned int numlower; | |
918 | unsigned int stacklen = 0; | |
dd662667 | 919 | unsigned int i; |
7c03b5d4 | 920 | bool remote = false; |
e9be9d5e MS |
921 | int err; |
922 | ||
f45827e8 EZ |
923 | err = -ENOMEM; |
924 | ufs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); | |
925 | if (!ufs) | |
e9be9d5e MS |
926 | goto out; |
927 | ||
f45827e8 EZ |
928 | err = ovl_parse_opt((char *) data, &ufs->config); |
929 | if (err) | |
930 | goto out_free_config; | |
931 | ||
e9be9d5e | 932 | err = -EINVAL; |
53a08cb9 MS |
933 | if (!ufs->config.lowerdir) { |
934 | pr_err("overlayfs: missing 'lowerdir'\n"); | |
e9be9d5e MS |
935 | goto out_free_config; |
936 | } | |
937 | ||
53a08cb9 MS |
938 | sb->s_stack_depth = 0; |
939 | if (ufs->config.upperdir) { | |
53a08cb9 MS |
940 | if (!ufs->config.workdir) { |
941 | pr_err("overlayfs: missing 'workdir'\n"); | |
942 | goto out_free_config; | |
943 | } | |
e9be9d5e | 944 | |
53a08cb9 MS |
945 | err = ovl_mount_dir(ufs->config.upperdir, &upperpath); |
946 | if (err) | |
947 | goto out_free_config; | |
e9be9d5e | 948 | |
71cbad7e | 949 | /* Upper fs should not be r/o */ |
950 | if (upperpath.mnt->mnt_sb->s_flags & MS_RDONLY) { | |
951 | pr_err("overlayfs: upper fs is r/o, try multi-lower layers mount\n"); | |
952 | err = -EINVAL; | |
953 | goto out_put_upperpath; | |
954 | } | |
955 | ||
53a08cb9 MS |
956 | err = ovl_mount_dir(ufs->config.workdir, &workpath); |
957 | if (err) | |
958 | goto out_put_upperpath; | |
959 | ||
2f83fd8c | 960 | err = -EINVAL; |
53a08cb9 MS |
961 | if (upperpath.mnt != workpath.mnt) { |
962 | pr_err("overlayfs: workdir and upperdir must reside under the same mount\n"); | |
963 | goto out_put_workpath; | |
964 | } | |
965 | if (!ovl_workdir_ok(workpath.dentry, upperpath.dentry)) { | |
966 | pr_err("overlayfs: workdir and upperdir must be separate subtrees\n"); | |
967 | goto out_put_workpath; | |
968 | } | |
969 | sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth; | |
cc259639 | 970 | } |
a78d9f0d MS |
971 | err = -ENOMEM; |
972 | lowertmp = kstrdup(ufs->config.lowerdir, GFP_KERNEL); | |
973 | if (!lowertmp) | |
ab508822 | 974 | goto out_put_workpath; |
69c433ed | 975 | |
a78d9f0d MS |
976 | err = -EINVAL; |
977 | stacklen = ovl_split_lowerdirs(lowertmp); | |
6be4506e | 978 | if (stacklen > OVL_MAX_STACK) { |
979 | pr_err("overlayfs: too many lower directries, limit is %d\n", | |
980 | OVL_MAX_STACK); | |
a78d9f0d | 981 | goto out_free_lowertmp; |
6be4506e | 982 | } else if (!ufs->config.upperdir && stacklen == 1) { |
983 | pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n"); | |
984 | goto out_free_lowertmp; | |
985 | } | |
a78d9f0d MS |
986 | |
987 | stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL); | |
988 | if (!stack) | |
989 | goto out_free_lowertmp; | |
990 | ||
991 | lower = lowertmp; | |
992 | for (numlower = 0; numlower < stacklen; numlower++) { | |
993 | err = ovl_lower_dir(lower, &stack[numlower], | |
7c03b5d4 MS |
994 | &ufs->lower_namelen, &sb->s_stack_depth, |
995 | &remote); | |
a78d9f0d MS |
996 | if (err) |
997 | goto out_put_lowerpath; | |
998 | ||
999 | lower = strchr(lower, '\0') + 1; | |
1000 | } | |
1001 | ||
69c433ed | 1002 | err = -EINVAL; |
ab508822 | 1003 | sb->s_stack_depth++; |
69c433ed MS |
1004 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { |
1005 | pr_err("overlayfs: maximum fs stacking depth exceeded\n"); | |
3b7a9a24 | 1006 | goto out_put_lowerpath; |
69c433ed MS |
1007 | } |
1008 | ||
53a08cb9 MS |
1009 | if (ufs->config.upperdir) { |
1010 | ufs->upper_mnt = clone_private_mount(&upperpath); | |
1011 | err = PTR_ERR(ufs->upper_mnt); | |
1012 | if (IS_ERR(ufs->upper_mnt)) { | |
1013 | pr_err("overlayfs: failed to clone upperpath\n"); | |
1014 | goto out_put_lowerpath; | |
1015 | } | |
3b7a9a24 | 1016 | |
53a08cb9 MS |
1017 | ufs->workdir = ovl_workdir_create(ufs->upper_mnt, workpath.dentry); |
1018 | err = PTR_ERR(ufs->workdir); | |
1019 | if (IS_ERR(ufs->workdir)) { | |
cc6f67bc MS |
1020 | pr_warn("overlayfs: failed to create directory %s/%s (errno: %i); mounting read-only\n", |
1021 | ufs->config.workdir, OVL_WORKDIR_NAME, -err); | |
1022 | sb->s_flags |= MS_RDONLY; | |
1023 | ufs->workdir = NULL; | |
53a08cb9 | 1024 | } |
e9be9d5e MS |
1025 | } |
1026 | ||
2f83fd8c | 1027 | err = -ENOMEM; |
a78d9f0d | 1028 | ufs->lower_mnt = kcalloc(numlower, sizeof(struct vfsmount *), GFP_KERNEL); |
dd662667 | 1029 | if (ufs->lower_mnt == NULL) |
3b7a9a24 | 1030 | goto out_put_workdir; |
a78d9f0d MS |
1031 | for (i = 0; i < numlower; i++) { |
1032 | struct vfsmount *mnt = clone_private_mount(&stack[i]); | |
dd662667 | 1033 | |
2f83fd8c | 1034 | err = PTR_ERR(mnt); |
a78d9f0d MS |
1035 | if (IS_ERR(mnt)) { |
1036 | pr_err("overlayfs: failed to clone lowerpath\n"); | |
1037 | goto out_put_lower_mnt; | |
1038 | } | |
1039 | /* | |
1040 | * Make lower_mnt R/O. That way fchmod/fchown on lower file | |
1041 | * will fail instead of modifying lower fs. | |
1042 | */ | |
1043 | mnt->mnt_flags |= MNT_READONLY; | |
dd662667 | 1044 | |
a78d9f0d MS |
1045 | ufs->lower_mnt[ufs->numlower] = mnt; |
1046 | ufs->numlower++; | |
1047 | } | |
e9be9d5e | 1048 | |
71cbad7e | 1049 | /* If the upper fs is nonexistent, we mark overlayfs r/o too */ |
1050 | if (!ufs->upper_mnt) | |
e9be9d5e MS |
1051 | sb->s_flags |= MS_RDONLY; |
1052 | ||
7c03b5d4 MS |
1053 | if (remote) |
1054 | sb->s_d_op = &ovl_reval_dentry_operations; | |
1055 | else | |
1056 | sb->s_d_op = &ovl_dentry_operations; | |
e9be9d5e MS |
1057 | |
1058 | err = -ENOMEM; | |
a78d9f0d | 1059 | oe = ovl_alloc_entry(numlower); |
3b7a9a24 MS |
1060 | if (!oe) |
1061 | goto out_put_lower_mnt; | |
e9be9d5e | 1062 | |
3b7a9a24 | 1063 | root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, oe)); |
e9be9d5e | 1064 | if (!root_dentry) |
3b7a9a24 | 1065 | goto out_free_oe; |
e9be9d5e MS |
1066 | |
1067 | mntput(upperpath.mnt); | |
a78d9f0d MS |
1068 | for (i = 0; i < numlower; i++) |
1069 | mntput(stack[i].mnt); | |
e9be9d5e | 1070 | path_put(&workpath); |
a78d9f0d | 1071 | kfree(lowertmp); |
e9be9d5e MS |
1072 | |
1073 | oe->__upperdentry = upperpath.dentry; | |
a78d9f0d MS |
1074 | for (i = 0; i < numlower; i++) { |
1075 | oe->lowerstack[i].dentry = stack[i].dentry; | |
1076 | oe->lowerstack[i].mnt = ufs->lower_mnt[i]; | |
1077 | } | |
0f95502a | 1078 | kfree(stack); |
e9be9d5e MS |
1079 | |
1080 | root_dentry->d_fsdata = oe; | |
1081 | ||
cc259639 | 1082 | sb->s_magic = OVERLAYFS_SUPER_MAGIC; |
e9be9d5e MS |
1083 | sb->s_op = &ovl_super_operations; |
1084 | sb->s_root = root_dentry; | |
1085 | sb->s_fs_info = ufs; | |
1086 | ||
1087 | return 0; | |
1088 | ||
3b7a9a24 MS |
1089 | out_free_oe: |
1090 | kfree(oe); | |
e9be9d5e | 1091 | out_put_lower_mnt: |
dd662667 MS |
1092 | for (i = 0; i < ufs->numlower; i++) |
1093 | mntput(ufs->lower_mnt[i]); | |
1094 | kfree(ufs->lower_mnt); | |
3b7a9a24 MS |
1095 | out_put_workdir: |
1096 | dput(ufs->workdir); | |
e9be9d5e | 1097 | mntput(ufs->upper_mnt); |
e9be9d5e | 1098 | out_put_lowerpath: |
a78d9f0d MS |
1099 | for (i = 0; i < numlower; i++) |
1100 | path_put(&stack[i]); | |
1101 | kfree(stack); | |
1102 | out_free_lowertmp: | |
1103 | kfree(lowertmp); | |
3b7a9a24 MS |
1104 | out_put_workpath: |
1105 | path_put(&workpath); | |
e9be9d5e MS |
1106 | out_put_upperpath: |
1107 | path_put(&upperpath); | |
e9be9d5e | 1108 | out_free_config: |
f45827e8 EZ |
1109 | kfree(ufs->config.lowerdir); |
1110 | kfree(ufs->config.upperdir); | |
1111 | kfree(ufs->config.workdir); | |
1112 | kfree(ufs); | |
e9be9d5e MS |
1113 | out: |
1114 | return err; | |
1115 | } | |
1116 | ||
1117 | static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, | |
1118 | const char *dev_name, void *raw_data) | |
1119 | { | |
1120 | return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); | |
1121 | } | |
1122 | ||
1123 | static struct file_system_type ovl_fs_type = { | |
1124 | .owner = THIS_MODULE, | |
ef94b186 | 1125 | .name = "overlay", |
e9be9d5e MS |
1126 | .mount = ovl_mount, |
1127 | .kill_sb = kill_anon_super, | |
1128 | }; | |
ef94b186 | 1129 | MODULE_ALIAS_FS("overlay"); |
e9be9d5e MS |
1130 | |
1131 | static int __init ovl_init(void) | |
1132 | { | |
1133 | return register_filesystem(&ovl_fs_type); | |
1134 | } | |
1135 | ||
1136 | static void __exit ovl_exit(void) | |
1137 | { | |
1138 | unregister_filesystem(&ovl_fs_type); | |
1139 | } | |
1140 | ||
1141 | module_init(ovl_init); | |
1142 | module_exit(ovl_exit); |