Commit | Line | Data |
---|---|---|
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> | |
cf9a6784 | 12 | #include <linux/pagemap.h> |
e9be9d5e MS |
13 | #include <linux/xattr.h> |
14 | #include <linux/security.h> | |
15 | #include <linux/mount.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/parser.h> | |
18 | #include <linux/module.h> | |
e458bcd1 | 19 | #include <linux/pagemap.h> |
e9be9d5e | 20 | #include <linux/sched.h> |
cc259639 | 21 | #include <linux/statfs.h> |
f45827e8 | 22 | #include <linux/seq_file.h> |
e9be9d5e MS |
23 | #include "overlayfs.h" |
24 | ||
25 | MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); | |
26 | MODULE_DESCRIPTION("Overlay filesystem"); | |
27 | MODULE_LICENSE("GPL"); | |
28 | ||
f45827e8 EZ |
29 | struct ovl_config { |
30 | char *lowerdir; | |
31 | char *upperdir; | |
32 | char *workdir; | |
8d3095f4 | 33 | bool default_permissions; |
f45827e8 EZ |
34 | }; |
35 | ||
e9be9d5e MS |
36 | /* private information held for overlayfs's superblock */ |
37 | struct ovl_fs { | |
38 | struct vfsmount *upper_mnt; | |
dd662667 MS |
39 | unsigned numlower; |
40 | struct vfsmount **lower_mnt; | |
e9be9d5e | 41 | struct dentry *workdir; |
cc259639 | 42 | long lower_namelen; |
f45827e8 EZ |
43 | /* pathnames of lower and upper dirs, for show_options */ |
44 | struct ovl_config config; | |
e9be9d5e MS |
45 | }; |
46 | ||
47 | struct ovl_dir_cache; | |
48 | ||
49 | /* private information held for every overlayfs dentry */ | |
50 | struct ovl_entry { | |
51 | struct dentry *__upperdentry; | |
e9be9d5e MS |
52 | struct ovl_dir_cache *cache; |
53 | union { | |
54 | struct { | |
55 | u64 version; | |
56 | bool opaque; | |
57 | }; | |
58 | struct rcu_head rcu; | |
59 | }; | |
dd662667 MS |
60 | unsigned numlower; |
61 | struct path lowerstack[]; | |
e9be9d5e MS |
62 | }; |
63 | ||
a78d9f0d MS |
64 | #define OVL_MAX_STACK 500 |
65 | ||
dd662667 MS |
66 | static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe) |
67 | { | |
68 | return oe->numlower ? oe->lowerstack[0].dentry : NULL; | |
69 | } | |
e9be9d5e MS |
70 | |
71 | enum ovl_path_type ovl_path_type(struct dentry *dentry) | |
72 | { | |
73 | struct ovl_entry *oe = dentry->d_fsdata; | |
1afaba1e | 74 | enum ovl_path_type type = 0; |
e9be9d5e MS |
75 | |
76 | if (oe->__upperdentry) { | |
1afaba1e MS |
77 | type = __OVL_PATH_UPPER; |
78 | ||
dd662667 | 79 | if (oe->numlower) { |
e9be9d5e | 80 | if (S_ISDIR(dentry->d_inode->i_mode)) |
1afaba1e MS |
81 | type |= __OVL_PATH_MERGE; |
82 | } else if (!oe->opaque) { | |
83 | type |= __OVL_PATH_PURE; | |
e9be9d5e | 84 | } |
9d7459d8 MS |
85 | } else { |
86 | if (oe->numlower > 1) | |
87 | type |= __OVL_PATH_MERGE; | |
e9be9d5e | 88 | } |
1afaba1e | 89 | return type; |
e9be9d5e MS |
90 | } |
91 | ||
92 | static struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe) | |
93 | { | |
71d50928 | 94 | return lockless_dereference(oe->__upperdentry); |
e9be9d5e MS |
95 | } |
96 | ||
97 | void ovl_path_upper(struct dentry *dentry, struct path *path) | |
98 | { | |
99 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
100 | struct ovl_entry *oe = dentry->d_fsdata; | |
101 | ||
102 | path->mnt = ofs->upper_mnt; | |
103 | path->dentry = ovl_upperdentry_dereference(oe); | |
104 | } | |
105 | ||
106 | enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path) | |
107 | { | |
e9be9d5e MS |
108 | enum ovl_path_type type = ovl_path_type(dentry); |
109 | ||
1afaba1e | 110 | if (!OVL_TYPE_UPPER(type)) |
e9be9d5e MS |
111 | ovl_path_lower(dentry, path); |
112 | else | |
113 | ovl_path_upper(dentry, path); | |
114 | ||
115 | return type; | |
116 | } | |
117 | ||
118 | struct dentry *ovl_dentry_upper(struct dentry *dentry) | |
119 | { | |
120 | struct ovl_entry *oe = dentry->d_fsdata; | |
121 | ||
122 | return ovl_upperdentry_dereference(oe); | |
123 | } | |
124 | ||
125 | struct dentry *ovl_dentry_lower(struct dentry *dentry) | |
126 | { | |
127 | struct ovl_entry *oe = dentry->d_fsdata; | |
128 | ||
dd662667 | 129 | return __ovl_dentry_lower(oe); |
e9be9d5e MS |
130 | } |
131 | ||
132 | struct dentry *ovl_dentry_real(struct dentry *dentry) | |
133 | { | |
134 | struct ovl_entry *oe = dentry->d_fsdata; | |
135 | struct dentry *realdentry; | |
136 | ||
137 | realdentry = ovl_upperdentry_dereference(oe); | |
138 | if (!realdentry) | |
dd662667 | 139 | realdentry = __ovl_dentry_lower(oe); |
e9be9d5e MS |
140 | |
141 | return realdentry; | |
142 | } | |
143 | ||
144 | struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper) | |
145 | { | |
146 | struct dentry *realdentry; | |
147 | ||
148 | realdentry = ovl_upperdentry_dereference(oe); | |
149 | if (realdentry) { | |
150 | *is_upper = true; | |
151 | } else { | |
dd662667 | 152 | realdentry = __ovl_dentry_lower(oe); |
e9be9d5e MS |
153 | *is_upper = false; |
154 | } | |
155 | return realdentry; | |
156 | } | |
157 | ||
8d3095f4 MS |
158 | struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode, |
159 | bool is_upper) | |
160 | { | |
161 | if (is_upper) { | |
162 | struct ovl_fs *ofs = inode->i_sb->s_fs_info; | |
163 | ||
164 | return ofs->upper_mnt; | |
165 | } else { | |
166 | return oe->numlower ? oe->lowerstack[0].mnt : NULL; | |
167 | } | |
168 | } | |
169 | ||
e9be9d5e MS |
170 | struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry) |
171 | { | |
172 | struct ovl_entry *oe = dentry->d_fsdata; | |
173 | ||
174 | return oe->cache; | |
175 | } | |
176 | ||
8d3095f4 MS |
177 | bool ovl_is_default_permissions(struct inode *inode) |
178 | { | |
179 | struct ovl_fs *ofs = inode->i_sb->s_fs_info; | |
180 | ||
181 | return ofs->config.default_permissions; | |
182 | } | |
183 | ||
e9be9d5e MS |
184 | void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache) |
185 | { | |
186 | struct ovl_entry *oe = dentry->d_fsdata; | |
187 | ||
188 | oe->cache = cache; | |
189 | } | |
190 | ||
191 | void ovl_path_lower(struct dentry *dentry, struct path *path) | |
192 | { | |
e9be9d5e MS |
193 | struct ovl_entry *oe = dentry->d_fsdata; |
194 | ||
dd662667 | 195 | *path = oe->numlower ? oe->lowerstack[0] : (struct path) { NULL, NULL }; |
e9be9d5e MS |
196 | } |
197 | ||
198 | int ovl_want_write(struct dentry *dentry) | |
199 | { | |
200 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
201 | return mnt_want_write(ofs->upper_mnt); | |
202 | } | |
203 | ||
204 | void ovl_drop_write(struct dentry *dentry) | |
205 | { | |
206 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
207 | mnt_drop_write(ofs->upper_mnt); | |
208 | } | |
209 | ||
210 | struct dentry *ovl_workdir(struct dentry *dentry) | |
211 | { | |
212 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
213 | return ofs->workdir; | |
214 | } | |
215 | ||
216 | bool ovl_dentry_is_opaque(struct dentry *dentry) | |
217 | { | |
218 | struct ovl_entry *oe = dentry->d_fsdata; | |
219 | return oe->opaque; | |
220 | } | |
221 | ||
222 | void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque) | |
223 | { | |
224 | struct ovl_entry *oe = dentry->d_fsdata; | |
225 | oe->opaque = opaque; | |
226 | } | |
227 | ||
228 | void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry) | |
229 | { | |
230 | struct ovl_entry *oe = dentry->d_fsdata; | |
231 | ||
5955102c | 232 | WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode)); |
e9be9d5e MS |
233 | WARN_ON(oe->__upperdentry); |
234 | BUG_ON(!upperdentry->d_inode); | |
235 | /* | |
236 | * Make sure upperdentry is consistent before making it visible to | |
237 | * ovl_upperdentry_dereference(). | |
238 | */ | |
239 | smp_wmb(); | |
240 | oe->__upperdentry = upperdentry; | |
241 | } | |
242 | ||
243 | void ovl_dentry_version_inc(struct dentry *dentry) | |
244 | { | |
245 | struct ovl_entry *oe = dentry->d_fsdata; | |
246 | ||
5955102c | 247 | WARN_ON(!inode_is_locked(dentry->d_inode)); |
e9be9d5e MS |
248 | oe->version++; |
249 | } | |
250 | ||
251 | u64 ovl_dentry_version_get(struct dentry *dentry) | |
252 | { | |
253 | struct ovl_entry *oe = dentry->d_fsdata; | |
254 | ||
5955102c | 255 | WARN_ON(!inode_is_locked(dentry->d_inode)); |
e9be9d5e MS |
256 | return oe->version; |
257 | } | |
258 | ||
259 | bool ovl_is_whiteout(struct dentry *dentry) | |
260 | { | |
261 | struct inode *inode = dentry->d_inode; | |
262 | ||
263 | return inode && IS_WHITEOUT(inode); | |
264 | } | |
265 | ||
266 | static bool ovl_is_opaquedir(struct dentry *dentry) | |
267 | { | |
268 | int res; | |
269 | char val; | |
270 | struct inode *inode = dentry->d_inode; | |
271 | ||
272 | if (!S_ISDIR(inode->i_mode) || !inode->i_op->getxattr) | |
273 | return false; | |
274 | ||
cead89bb | 275 | res = inode->i_op->getxattr(dentry, OVL_XATTR_OPAQUE, &val, 1); |
e9be9d5e MS |
276 | if (res == 1 && val == 'y') |
277 | return true; | |
278 | ||
279 | return false; | |
280 | } | |
281 | ||
282 | static void ovl_dentry_release(struct dentry *dentry) | |
283 | { | |
284 | struct ovl_entry *oe = dentry->d_fsdata; | |
285 | ||
286 | if (oe) { | |
dd662667 MS |
287 | unsigned int i; |
288 | ||
e9be9d5e | 289 | dput(oe->__upperdentry); |
dd662667 MS |
290 | for (i = 0; i < oe->numlower; i++) |
291 | dput(oe->lowerstack[i].dentry); | |
e9be9d5e MS |
292 | kfree_rcu(oe, rcu); |
293 | } | |
294 | } | |
295 | ||
7c03b5d4 MS |
296 | static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
297 | { | |
298 | struct ovl_entry *oe = dentry->d_fsdata; | |
299 | unsigned int i; | |
300 | int ret = 1; | |
301 | ||
302 | for (i = 0; i < oe->numlower; i++) { | |
303 | struct dentry *d = oe->lowerstack[i].dentry; | |
304 | ||
305 | if (d->d_flags & DCACHE_OP_REVALIDATE) { | |
306 | ret = d->d_op->d_revalidate(d, flags); | |
307 | if (ret < 0) | |
308 | return ret; | |
309 | if (!ret) { | |
310 | if (!(flags & LOOKUP_RCU)) | |
311 | d_invalidate(d); | |
312 | return -ESTALE; | |
313 | } | |
314 | } | |
315 | } | |
316 | return 1; | |
317 | } | |
318 | ||
319 | static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) | |
320 | { | |
321 | struct ovl_entry *oe = dentry->d_fsdata; | |
322 | unsigned int i; | |
323 | int ret = 1; | |
324 | ||
325 | for (i = 0; i < oe->numlower; i++) { | |
326 | struct dentry *d = oe->lowerstack[i].dentry; | |
327 | ||
328 | if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) { | |
329 | ret = d->d_op->d_weak_revalidate(d, flags); | |
330 | if (ret <= 0) | |
331 | break; | |
332 | } | |
333 | } | |
334 | return ret; | |
335 | } | |
336 | ||
e9be9d5e MS |
337 | static const struct dentry_operations ovl_dentry_operations = { |
338 | .d_release = ovl_dentry_release, | |
4bacc9c9 | 339 | .d_select_inode = ovl_d_select_inode, |
e9be9d5e MS |
340 | }; |
341 | ||
7c03b5d4 MS |
342 | static const struct dentry_operations ovl_reval_dentry_operations = { |
343 | .d_release = ovl_dentry_release, | |
344 | .d_revalidate = ovl_dentry_revalidate, | |
345 | .d_weak_revalidate = ovl_dentry_weak_revalidate, | |
346 | }; | |
347 | ||
dd662667 | 348 | static struct ovl_entry *ovl_alloc_entry(unsigned int numlower) |
e9be9d5e | 349 | { |
dd662667 MS |
350 | size_t size = offsetof(struct ovl_entry, lowerstack[numlower]); |
351 | struct ovl_entry *oe = kzalloc(size, GFP_KERNEL); | |
352 | ||
353 | if (oe) | |
354 | oe->numlower = numlower; | |
355 | ||
356 | return oe; | |
e9be9d5e MS |
357 | } |
358 | ||
7c03b5d4 MS |
359 | static bool ovl_dentry_remote(struct dentry *dentry) |
360 | { | |
361 | return dentry->d_flags & | |
362 | (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE); | |
363 | } | |
364 | ||
365 | static bool ovl_dentry_weird(struct dentry *dentry) | |
366 | { | |
367 | return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT | | |
368 | DCACHE_MANAGE_TRANSIT | | |
369 | DCACHE_OP_HASH | | |
370 | DCACHE_OP_COMPARE); | |
371 | } | |
372 | ||
e9be9d5e MS |
373 | static inline struct dentry *ovl_lookup_real(struct dentry *dir, |
374 | struct qstr *name) | |
375 | { | |
376 | struct dentry *dentry; | |
377 | ||
5955102c | 378 | inode_lock(dir->d_inode); |
e9be9d5e | 379 | dentry = lookup_one_len(name->name, dir, name->len); |
5955102c | 380 | inode_unlock(dir->d_inode); |
e9be9d5e MS |
381 | |
382 | if (IS_ERR(dentry)) { | |
383 | if (PTR_ERR(dentry) == -ENOENT) | |
384 | dentry = NULL; | |
385 | } else if (!dentry->d_inode) { | |
386 | dput(dentry); | |
387 | dentry = NULL; | |
7c03b5d4 | 388 | } else if (ovl_dentry_weird(dentry)) { |
a6f15d9a | 389 | dput(dentry); |
7c03b5d4 | 390 | /* Don't support traversing automounts and other weirdness */ |
a6f15d9a | 391 | dentry = ERR_PTR(-EREMOTE); |
e9be9d5e MS |
392 | } |
393 | return dentry; | |
394 | } | |
395 | ||
5ef88da5 MS |
396 | /* |
397 | * Returns next layer in stack starting from top. | |
398 | * Returns -1 if this is the last layer. | |
399 | */ | |
400 | int ovl_path_next(int idx, struct dentry *dentry, struct path *path) | |
401 | { | |
402 | struct ovl_entry *oe = dentry->d_fsdata; | |
403 | ||
404 | BUG_ON(idx < 0); | |
405 | if (idx == 0) { | |
406 | ovl_path_upper(dentry, path); | |
407 | if (path->dentry) | |
408 | return oe->numlower ? 1 : -1; | |
409 | idx++; | |
410 | } | |
411 | BUG_ON(idx > oe->numlower); | |
412 | *path = oe->lowerstack[idx - 1]; | |
413 | ||
414 | return (idx < oe->numlower) ? idx + 1 : -1; | |
415 | } | |
416 | ||
e9be9d5e MS |
417 | struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, |
418 | unsigned int flags) | |
419 | { | |
420 | struct ovl_entry *oe; | |
3d3c6b89 MS |
421 | struct ovl_entry *poe = dentry->d_parent->d_fsdata; |
422 | struct path *stack = NULL; | |
423 | struct dentry *upperdir, *upperdentry = NULL; | |
424 | unsigned int ctr = 0; | |
e9be9d5e | 425 | struct inode *inode = NULL; |
3d3c6b89 MS |
426 | bool upperopaque = false; |
427 | struct dentry *this, *prev = NULL; | |
428 | unsigned int i; | |
e9be9d5e MS |
429 | int err; |
430 | ||
3d3c6b89 | 431 | upperdir = ovl_upperdentry_dereference(poe); |
e9be9d5e | 432 | if (upperdir) { |
3d3c6b89 MS |
433 | this = ovl_lookup_real(upperdir, &dentry->d_name); |
434 | err = PTR_ERR(this); | |
435 | if (IS_ERR(this)) | |
436 | goto out; | |
437 | ||
3e01cee3 | 438 | if (this) { |
7c03b5d4 MS |
439 | if (unlikely(ovl_dentry_remote(this))) { |
440 | dput(this); | |
441 | err = -EREMOTE; | |
442 | goto out; | |
443 | } | |
3d3c6b89 MS |
444 | if (ovl_is_whiteout(this)) { |
445 | dput(this); | |
446 | this = NULL; | |
447 | upperopaque = true; | |
3e01cee3 | 448 | } else if (poe->numlower && ovl_is_opaquedir(this)) { |
3d3c6b89 | 449 | upperopaque = true; |
e9be9d5e MS |
450 | } |
451 | } | |
3d3c6b89 | 452 | upperdentry = prev = this; |
e9be9d5e | 453 | } |
3d3c6b89 MS |
454 | |
455 | if (!upperopaque && poe->numlower) { | |
456 | err = -ENOMEM; | |
457 | stack = kcalloc(poe->numlower, sizeof(struct path), GFP_KERNEL); | |
458 | if (!stack) | |
459 | goto out_put_upper; | |
e9be9d5e MS |
460 | } |
461 | ||
3d3c6b89 MS |
462 | for (i = 0; !upperopaque && i < poe->numlower; i++) { |
463 | bool opaque = false; | |
464 | struct path lowerpath = poe->lowerstack[i]; | |
465 | ||
3d3c6b89 MS |
466 | this = ovl_lookup_real(lowerpath.dentry, &dentry->d_name); |
467 | err = PTR_ERR(this); | |
09e10322 MS |
468 | if (IS_ERR(this)) { |
469 | /* | |
470 | * If it's positive, then treat ENAMETOOLONG as ENOENT. | |
471 | */ | |
472 | if (err == -ENAMETOOLONG && (upperdentry || ctr)) | |
473 | continue; | |
3d3c6b89 | 474 | goto out_put; |
09e10322 | 475 | } |
3d3c6b89 MS |
476 | if (!this) |
477 | continue; | |
3e01cee3 MS |
478 | if (ovl_is_whiteout(this)) { |
479 | dput(this); | |
480 | break; | |
481 | } | |
3d3c6b89 | 482 | /* |
3e01cee3 MS |
483 | * Only makes sense to check opaque dir if this is not the |
484 | * lowermost layer. | |
3d3c6b89 | 485 | */ |
3e01cee3 MS |
486 | if (i < poe->numlower - 1 && ovl_is_opaquedir(this)) |
487 | opaque = true; | |
a425c037 | 488 | |
489 | if (prev && (!S_ISDIR(prev->d_inode->i_mode) || | |
490 | !S_ISDIR(this->d_inode->i_mode))) { | |
491 | /* | |
492 | * FIXME: check for upper-opaqueness maybe better done | |
493 | * in remove code. | |
494 | */ | |
3d3c6b89 MS |
495 | if (prev == upperdentry) |
496 | upperopaque = true; | |
497 | dput(this); | |
498 | break; | |
499 | } | |
a425c037 | 500 | /* |
501 | * If this is a non-directory then stop here. | |
502 | */ | |
503 | if (!S_ISDIR(this->d_inode->i_mode)) | |
504 | opaque = true; | |
505 | ||
3d3c6b89 MS |
506 | stack[ctr].dentry = this; |
507 | stack[ctr].mnt = lowerpath.mnt; | |
508 | ctr++; | |
509 | prev = this; | |
510 | if (opaque) | |
511 | break; | |
e9be9d5e MS |
512 | } |
513 | ||
3d3c6b89 MS |
514 | oe = ovl_alloc_entry(ctr); |
515 | err = -ENOMEM; | |
516 | if (!oe) | |
517 | goto out_put; | |
518 | ||
519 | if (upperdentry || ctr) { | |
e9be9d5e MS |
520 | struct dentry *realdentry; |
521 | ||
3d3c6b89 MS |
522 | realdentry = upperdentry ? upperdentry : stack[0].dentry; |
523 | ||
e9be9d5e MS |
524 | err = -ENOMEM; |
525 | inode = ovl_new_inode(dentry->d_sb, realdentry->d_inode->i_mode, | |
526 | oe); | |
527 | if (!inode) | |
3d3c6b89 | 528 | goto out_free_oe; |
e9be9d5e MS |
529 | ovl_copyattr(realdentry->d_inode, inode); |
530 | } | |
531 | ||
3d3c6b89 | 532 | oe->opaque = upperopaque; |
e9be9d5e | 533 | oe->__upperdentry = upperdentry; |
3d3c6b89 MS |
534 | memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr); |
535 | kfree(stack); | |
e9be9d5e MS |
536 | dentry->d_fsdata = oe; |
537 | d_add(dentry, inode); | |
538 | ||
539 | return NULL; | |
540 | ||
3d3c6b89 | 541 | out_free_oe: |
e9be9d5e | 542 | kfree(oe); |
3d3c6b89 MS |
543 | out_put: |
544 | for (i = 0; i < ctr; i++) | |
545 | dput(stack[i].dentry); | |
546 | kfree(stack); | |
547 | out_put_upper: | |
548 | dput(upperdentry); | |
e9be9d5e MS |
549 | out: |
550 | return ERR_PTR(err); | |
551 | } | |
552 | ||
553 | struct file *ovl_path_open(struct path *path, int flags) | |
554 | { | |
555 | return dentry_open(path, flags, current_cred()); | |
556 | } | |
557 | ||
558 | static void ovl_put_super(struct super_block *sb) | |
559 | { | |
560 | struct ovl_fs *ufs = sb->s_fs_info; | |
dd662667 | 561 | unsigned i; |
e9be9d5e MS |
562 | |
563 | dput(ufs->workdir); | |
564 | mntput(ufs->upper_mnt); | |
dd662667 MS |
565 | for (i = 0; i < ufs->numlower; i++) |
566 | mntput(ufs->lower_mnt[i]); | |
5ffdbe8b | 567 | kfree(ufs->lower_mnt); |
e9be9d5e | 568 | |
f45827e8 EZ |
569 | kfree(ufs->config.lowerdir); |
570 | kfree(ufs->config.upperdir); | |
571 | kfree(ufs->config.workdir); | |
e9be9d5e MS |
572 | kfree(ufs); |
573 | } | |
574 | ||
cc259639 AW |
575 | /** |
576 | * ovl_statfs | |
577 | * @sb: The overlayfs super block | |
578 | * @buf: The struct kstatfs to fill in with stats | |
579 | * | |
580 | * Get the filesystem statistics. As writes always target the upper layer | |
4ebc5818 | 581 | * filesystem pass the statfs to the upper filesystem (if it exists) |
cc259639 AW |
582 | */ |
583 | static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) | |
584 | { | |
585 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
586 | struct dentry *root_dentry = dentry->d_sb->s_root; | |
587 | struct path path; | |
588 | int err; | |
589 | ||
4ebc5818 | 590 | ovl_path_real(root_dentry, &path); |
cc259639 AW |
591 | |
592 | err = vfs_statfs(&path, buf); | |
593 | if (!err) { | |
594 | buf->f_namelen = max(buf->f_namelen, ofs->lower_namelen); | |
595 | buf->f_type = OVERLAYFS_SUPER_MAGIC; | |
596 | } | |
597 | ||
598 | return err; | |
599 | } | |
600 | ||
f45827e8 EZ |
601 | /** |
602 | * ovl_show_options | |
603 | * | |
604 | * Prints the mount options for a given superblock. | |
605 | * Returns zero; does not fail. | |
606 | */ | |
607 | static int ovl_show_options(struct seq_file *m, struct dentry *dentry) | |
608 | { | |
609 | struct super_block *sb = dentry->d_sb; | |
610 | struct ovl_fs *ufs = sb->s_fs_info; | |
611 | ||
a068acf2 | 612 | seq_show_option(m, "lowerdir", ufs->config.lowerdir); |
53a08cb9 | 613 | if (ufs->config.upperdir) { |
a068acf2 KC |
614 | seq_show_option(m, "upperdir", ufs->config.upperdir); |
615 | seq_show_option(m, "workdir", ufs->config.workdir); | |
53a08cb9 | 616 | } |
8d3095f4 MS |
617 | if (ufs->config.default_permissions) |
618 | seq_puts(m, ",default_permissions"); | |
f45827e8 EZ |
619 | return 0; |
620 | } | |
621 | ||
3cdf6fe9 SL |
622 | static int ovl_remount(struct super_block *sb, int *flags, char *data) |
623 | { | |
624 | struct ovl_fs *ufs = sb->s_fs_info; | |
625 | ||
cc6f67bc | 626 | if (!(*flags & MS_RDONLY) && (!ufs->upper_mnt || !ufs->workdir)) |
3cdf6fe9 SL |
627 | return -EROFS; |
628 | ||
629 | return 0; | |
630 | } | |
631 | ||
e9be9d5e MS |
632 | static const struct super_operations ovl_super_operations = { |
633 | .put_super = ovl_put_super, | |
cc259639 | 634 | .statfs = ovl_statfs, |
f45827e8 | 635 | .show_options = ovl_show_options, |
3cdf6fe9 | 636 | .remount_fs = ovl_remount, |
e9be9d5e MS |
637 | }; |
638 | ||
639 | enum { | |
640 | OPT_LOWERDIR, | |
641 | OPT_UPPERDIR, | |
642 | OPT_WORKDIR, | |
8d3095f4 | 643 | OPT_DEFAULT_PERMISSIONS, |
e9be9d5e MS |
644 | OPT_ERR, |
645 | }; | |
646 | ||
647 | static const match_table_t ovl_tokens = { | |
648 | {OPT_LOWERDIR, "lowerdir=%s"}, | |
649 | {OPT_UPPERDIR, "upperdir=%s"}, | |
650 | {OPT_WORKDIR, "workdir=%s"}, | |
8d3095f4 | 651 | {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, |
e9be9d5e MS |
652 | {OPT_ERR, NULL} |
653 | }; | |
654 | ||
91c77947 MS |
655 | static char *ovl_next_opt(char **s) |
656 | { | |
657 | char *sbegin = *s; | |
658 | char *p; | |
659 | ||
660 | if (sbegin == NULL) | |
661 | return NULL; | |
662 | ||
663 | for (p = sbegin; *p; p++) { | |
664 | if (*p == '\\') { | |
665 | p++; | |
666 | if (!*p) | |
667 | break; | |
668 | } else if (*p == ',') { | |
669 | *p = '\0'; | |
670 | *s = p + 1; | |
671 | return sbegin; | |
672 | } | |
673 | } | |
674 | *s = NULL; | |
675 | return sbegin; | |
676 | } | |
677 | ||
e9be9d5e MS |
678 | static int ovl_parse_opt(char *opt, struct ovl_config *config) |
679 | { | |
680 | char *p; | |
681 | ||
91c77947 | 682 | while ((p = ovl_next_opt(&opt)) != NULL) { |
e9be9d5e MS |
683 | int token; |
684 | substring_t args[MAX_OPT_ARGS]; | |
685 | ||
686 | if (!*p) | |
687 | continue; | |
688 | ||
689 | token = match_token(p, ovl_tokens, args); | |
690 | switch (token) { | |
691 | case OPT_UPPERDIR: | |
692 | kfree(config->upperdir); | |
693 | config->upperdir = match_strdup(&args[0]); | |
694 | if (!config->upperdir) | |
695 | return -ENOMEM; | |
696 | break; | |
697 | ||
698 | case OPT_LOWERDIR: | |
699 | kfree(config->lowerdir); | |
700 | config->lowerdir = match_strdup(&args[0]); | |
701 | if (!config->lowerdir) | |
702 | return -ENOMEM; | |
703 | break; | |
704 | ||
705 | case OPT_WORKDIR: | |
706 | kfree(config->workdir); | |
707 | config->workdir = match_strdup(&args[0]); | |
708 | if (!config->workdir) | |
709 | return -ENOMEM; | |
710 | break; | |
711 | ||
8d3095f4 MS |
712 | case OPT_DEFAULT_PERMISSIONS: |
713 | config->default_permissions = true; | |
714 | break; | |
715 | ||
e9be9d5e | 716 | default: |
bead55ef | 717 | pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p); |
e9be9d5e MS |
718 | return -EINVAL; |
719 | } | |
720 | } | |
71cbad7e | 721 | |
722 | /* Workdir is useless in non-upper mount */ | |
723 | if (!config->upperdir && config->workdir) { | |
724 | pr_info("overlayfs: option \"workdir=%s\" is useless in a non-upper mount, ignore\n", | |
725 | config->workdir); | |
726 | kfree(config->workdir); | |
727 | config->workdir = NULL; | |
728 | } | |
729 | ||
e9be9d5e MS |
730 | return 0; |
731 | } | |
732 | ||
733 | #define OVL_WORKDIR_NAME "work" | |
734 | ||
735 | static struct dentry *ovl_workdir_create(struct vfsmount *mnt, | |
736 | struct dentry *dentry) | |
737 | { | |
738 | struct inode *dir = dentry->d_inode; | |
739 | struct dentry *work; | |
740 | int err; | |
741 | bool retried = false; | |
742 | ||
743 | err = mnt_want_write(mnt); | |
744 | if (err) | |
745 | return ERR_PTR(err); | |
746 | ||
5955102c | 747 | inode_lock_nested(dir, I_MUTEX_PARENT); |
e9be9d5e MS |
748 | retry: |
749 | work = lookup_one_len(OVL_WORKDIR_NAME, dentry, | |
750 | strlen(OVL_WORKDIR_NAME)); | |
751 | ||
752 | if (!IS_ERR(work)) { | |
753 | struct kstat stat = { | |
754 | .mode = S_IFDIR | 0, | |
755 | }; | |
756 | ||
757 | if (work->d_inode) { | |
758 | err = -EEXIST; | |
759 | if (retried) | |
760 | goto out_dput; | |
761 | ||
762 | retried = true; | |
763 | ovl_cleanup(dir, work); | |
764 | dput(work); | |
765 | goto retry; | |
766 | } | |
767 | ||
768 | err = ovl_create_real(dir, work, &stat, NULL, NULL, true); | |
769 | if (err) | |
770 | goto out_dput; | |
771 | } | |
772 | out_unlock: | |
5955102c | 773 | inode_unlock(dir); |
e9be9d5e MS |
774 | mnt_drop_write(mnt); |
775 | ||
776 | return work; | |
777 | ||
778 | out_dput: | |
779 | dput(work); | |
780 | work = ERR_PTR(err); | |
781 | goto out_unlock; | |
782 | } | |
783 | ||
91c77947 MS |
784 | static void ovl_unescape(char *s) |
785 | { | |
786 | char *d = s; | |
787 | ||
788 | for (;; s++, d++) { | |
789 | if (*s == '\\') | |
790 | s++; | |
791 | *d = *s; | |
792 | if (!*s) | |
793 | break; | |
794 | } | |
795 | } | |
796 | ||
ab508822 MS |
797 | static int ovl_mount_dir_noesc(const char *name, struct path *path) |
798 | { | |
a78d9f0d | 799 | int err = -EINVAL; |
ab508822 | 800 | |
a78d9f0d MS |
801 | if (!*name) { |
802 | pr_err("overlayfs: empty lowerdir\n"); | |
803 | goto out; | |
804 | } | |
ab508822 MS |
805 | err = kern_path(name, LOOKUP_FOLLOW, path); |
806 | if (err) { | |
807 | pr_err("overlayfs: failed to resolve '%s': %i\n", name, err); | |
808 | goto out; | |
809 | } | |
810 | err = -EINVAL; | |
7c03b5d4 | 811 | if (ovl_dentry_weird(path->dentry)) { |
ab508822 MS |
812 | pr_err("overlayfs: filesystem on '%s' not supported\n", name); |
813 | goto out_put; | |
814 | } | |
815 | if (!S_ISDIR(path->dentry->d_inode->i_mode)) { | |
816 | pr_err("overlayfs: '%s' not a directory\n", name); | |
817 | goto out_put; | |
818 | } | |
819 | return 0; | |
820 | ||
821 | out_put: | |
822 | path_put(path); | |
823 | out: | |
824 | return err; | |
825 | } | |
826 | ||
827 | static int ovl_mount_dir(const char *name, struct path *path) | |
828 | { | |
829 | int err = -ENOMEM; | |
830 | char *tmp = kstrdup(name, GFP_KERNEL); | |
831 | ||
832 | if (tmp) { | |
833 | ovl_unescape(tmp); | |
834 | err = ovl_mount_dir_noesc(tmp, path); | |
7c03b5d4 MS |
835 | |
836 | if (!err) | |
837 | if (ovl_dentry_remote(path->dentry)) { | |
838 | pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n", | |
839 | tmp); | |
840 | path_put(path); | |
841 | err = -EINVAL; | |
842 | } | |
ab508822 MS |
843 | kfree(tmp); |
844 | } | |
845 | return err; | |
846 | } | |
847 | ||
848 | static int ovl_lower_dir(const char *name, struct path *path, long *namelen, | |
7c03b5d4 | 849 | int *stack_depth, bool *remote) |
ab508822 MS |
850 | { |
851 | int err; | |
852 | struct kstatfs statfs; | |
853 | ||
a78d9f0d | 854 | err = ovl_mount_dir_noesc(name, path); |
ab508822 MS |
855 | if (err) |
856 | goto out; | |
857 | ||
858 | err = vfs_statfs(path, &statfs); | |
859 | if (err) { | |
860 | pr_err("overlayfs: statfs failed on '%s'\n", name); | |
861 | goto out_put; | |
862 | } | |
863 | *namelen = max(*namelen, statfs.f_namelen); | |
864 | *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); | |
865 | ||
7c03b5d4 MS |
866 | if (ovl_dentry_remote(path->dentry)) |
867 | *remote = true; | |
868 | ||
ab508822 MS |
869 | return 0; |
870 | ||
871 | out_put: | |
872 | path_put(path); | |
873 | out: | |
874 | return err; | |
875 | } | |
876 | ||
e9be9d5e MS |
877 | /* Workdir should not be subdir of upperdir and vice versa */ |
878 | static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) | |
879 | { | |
880 | bool ok = false; | |
881 | ||
882 | if (workdir != upperdir) { | |
883 | ok = (lock_rename(workdir, upperdir) == NULL); | |
884 | unlock_rename(workdir, upperdir); | |
885 | } | |
886 | return ok; | |
887 | } | |
888 | ||
a78d9f0d MS |
889 | static unsigned int ovl_split_lowerdirs(char *str) |
890 | { | |
891 | unsigned int ctr = 1; | |
892 | char *s, *d; | |
893 | ||
894 | for (s = d = str;; s++, d++) { | |
895 | if (*s == '\\') { | |
896 | s++; | |
897 | } else if (*s == ':') { | |
898 | *d = '\0'; | |
899 | ctr++; | |
900 | continue; | |
901 | } | |
902 | *d = *s; | |
903 | if (!*s) | |
904 | break; | |
905 | } | |
906 | return ctr; | |
907 | } | |
908 | ||
e9be9d5e MS |
909 | static int ovl_fill_super(struct super_block *sb, void *data, int silent) |
910 | { | |
53a08cb9 MS |
911 | struct path upperpath = { NULL, NULL }; |
912 | struct path workpath = { NULL, NULL }; | |
e9be9d5e MS |
913 | struct dentry *root_dentry; |
914 | struct ovl_entry *oe; | |
915 | struct ovl_fs *ufs; | |
a78d9f0d MS |
916 | struct path *stack = NULL; |
917 | char *lowertmp; | |
918 | char *lower; | |
919 | unsigned int numlower; | |
920 | unsigned int stacklen = 0; | |
dd662667 | 921 | unsigned int i; |
7c03b5d4 | 922 | bool remote = false; |
e9be9d5e MS |
923 | int err; |
924 | ||
f45827e8 EZ |
925 | err = -ENOMEM; |
926 | ufs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); | |
927 | if (!ufs) | |
e9be9d5e MS |
928 | goto out; |
929 | ||
f45827e8 EZ |
930 | err = ovl_parse_opt((char *) data, &ufs->config); |
931 | if (err) | |
932 | goto out_free_config; | |
933 | ||
e9be9d5e | 934 | err = -EINVAL; |
53a08cb9 MS |
935 | if (!ufs->config.lowerdir) { |
936 | pr_err("overlayfs: missing 'lowerdir'\n"); | |
e9be9d5e MS |
937 | goto out_free_config; |
938 | } | |
939 | ||
53a08cb9 | 940 | sb->s_stack_depth = 0; |
cf9a6784 | 941 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
53a08cb9 | 942 | if (ufs->config.upperdir) { |
53a08cb9 MS |
943 | if (!ufs->config.workdir) { |
944 | pr_err("overlayfs: missing 'workdir'\n"); | |
945 | goto out_free_config; | |
946 | } | |
e9be9d5e | 947 | |
53a08cb9 MS |
948 | err = ovl_mount_dir(ufs->config.upperdir, &upperpath); |
949 | if (err) | |
950 | goto out_free_config; | |
e9be9d5e | 951 | |
71cbad7e | 952 | /* Upper fs should not be r/o */ |
953 | if (upperpath.mnt->mnt_sb->s_flags & MS_RDONLY) { | |
954 | pr_err("overlayfs: upper fs is r/o, try multi-lower layers mount\n"); | |
955 | err = -EINVAL; | |
956 | goto out_put_upperpath; | |
957 | } | |
958 | ||
53a08cb9 MS |
959 | err = ovl_mount_dir(ufs->config.workdir, &workpath); |
960 | if (err) | |
961 | goto out_put_upperpath; | |
962 | ||
2f83fd8c | 963 | err = -EINVAL; |
53a08cb9 MS |
964 | if (upperpath.mnt != workpath.mnt) { |
965 | pr_err("overlayfs: workdir and upperdir must reside under the same mount\n"); | |
966 | goto out_put_workpath; | |
967 | } | |
968 | if (!ovl_workdir_ok(workpath.dentry, upperpath.dentry)) { | |
969 | pr_err("overlayfs: workdir and upperdir must be separate subtrees\n"); | |
970 | goto out_put_workpath; | |
971 | } | |
972 | sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth; | |
cc259639 | 973 | } |
a78d9f0d MS |
974 | err = -ENOMEM; |
975 | lowertmp = kstrdup(ufs->config.lowerdir, GFP_KERNEL); | |
976 | if (!lowertmp) | |
ab508822 | 977 | goto out_put_workpath; |
69c433ed | 978 | |
a78d9f0d MS |
979 | err = -EINVAL; |
980 | stacklen = ovl_split_lowerdirs(lowertmp); | |
6be4506e | 981 | if (stacklen > OVL_MAX_STACK) { |
982 | pr_err("overlayfs: too many lower directries, limit is %d\n", | |
983 | OVL_MAX_STACK); | |
a78d9f0d | 984 | goto out_free_lowertmp; |
6be4506e | 985 | } else if (!ufs->config.upperdir && stacklen == 1) { |
986 | pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n"); | |
987 | goto out_free_lowertmp; | |
988 | } | |
a78d9f0d MS |
989 | |
990 | stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL); | |
991 | if (!stack) | |
992 | goto out_free_lowertmp; | |
993 | ||
994 | lower = lowertmp; | |
995 | for (numlower = 0; numlower < stacklen; numlower++) { | |
996 | err = ovl_lower_dir(lower, &stack[numlower], | |
7c03b5d4 MS |
997 | &ufs->lower_namelen, &sb->s_stack_depth, |
998 | &remote); | |
a78d9f0d MS |
999 | if (err) |
1000 | goto out_put_lowerpath; | |
1001 | ||
1002 | lower = strchr(lower, '\0') + 1; | |
1003 | } | |
1004 | ||
69c433ed | 1005 | err = -EINVAL; |
ab508822 | 1006 | sb->s_stack_depth++; |
69c433ed MS |
1007 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { |
1008 | pr_err("overlayfs: maximum fs stacking depth exceeded\n"); | |
3b7a9a24 | 1009 | goto out_put_lowerpath; |
69c433ed MS |
1010 | } |
1011 | ||
53a08cb9 MS |
1012 | if (ufs->config.upperdir) { |
1013 | ufs->upper_mnt = clone_private_mount(&upperpath); | |
1014 | err = PTR_ERR(ufs->upper_mnt); | |
1015 | if (IS_ERR(ufs->upper_mnt)) { | |
1016 | pr_err("overlayfs: failed to clone upperpath\n"); | |
1017 | goto out_put_lowerpath; | |
1018 | } | |
3b7a9a24 | 1019 | |
53a08cb9 MS |
1020 | ufs->workdir = ovl_workdir_create(ufs->upper_mnt, workpath.dentry); |
1021 | err = PTR_ERR(ufs->workdir); | |
1022 | if (IS_ERR(ufs->workdir)) { | |
cc6f67bc MS |
1023 | pr_warn("overlayfs: failed to create directory %s/%s (errno: %i); mounting read-only\n", |
1024 | ufs->config.workdir, OVL_WORKDIR_NAME, -err); | |
1025 | sb->s_flags |= MS_RDONLY; | |
1026 | ufs->workdir = NULL; | |
53a08cb9 | 1027 | } |
e9be9d5e MS |
1028 | } |
1029 | ||
2f83fd8c | 1030 | err = -ENOMEM; |
a78d9f0d | 1031 | ufs->lower_mnt = kcalloc(numlower, sizeof(struct vfsmount *), GFP_KERNEL); |
dd662667 | 1032 | if (ufs->lower_mnt == NULL) |
3b7a9a24 | 1033 | goto out_put_workdir; |
a78d9f0d MS |
1034 | for (i = 0; i < numlower; i++) { |
1035 | struct vfsmount *mnt = clone_private_mount(&stack[i]); | |
dd662667 | 1036 | |
2f83fd8c | 1037 | err = PTR_ERR(mnt); |
a78d9f0d MS |
1038 | if (IS_ERR(mnt)) { |
1039 | pr_err("overlayfs: failed to clone lowerpath\n"); | |
1040 | goto out_put_lower_mnt; | |
1041 | } | |
1042 | /* | |
1043 | * Make lower_mnt R/O. That way fchmod/fchown on lower file | |
1044 | * will fail instead of modifying lower fs. | |
1045 | */ | |
1046 | mnt->mnt_flags |= MNT_READONLY; | |
dd662667 | 1047 | |
a78d9f0d MS |
1048 | ufs->lower_mnt[ufs->numlower] = mnt; |
1049 | ufs->numlower++; | |
1050 | } | |
e9be9d5e | 1051 | |
71cbad7e | 1052 | /* If the upper fs is nonexistent, we mark overlayfs r/o too */ |
1053 | if (!ufs->upper_mnt) | |
e9be9d5e MS |
1054 | sb->s_flags |= MS_RDONLY; |
1055 | ||
7c03b5d4 MS |
1056 | if (remote) |
1057 | sb->s_d_op = &ovl_reval_dentry_operations; | |
1058 | else | |
1059 | sb->s_d_op = &ovl_dentry_operations; | |
e9be9d5e MS |
1060 | |
1061 | err = -ENOMEM; | |
a78d9f0d | 1062 | oe = ovl_alloc_entry(numlower); |
3b7a9a24 MS |
1063 | if (!oe) |
1064 | goto out_put_lower_mnt; | |
e9be9d5e | 1065 | |
3b7a9a24 | 1066 | root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, oe)); |
e9be9d5e | 1067 | if (!root_dentry) |
3b7a9a24 | 1068 | goto out_free_oe; |
e9be9d5e MS |
1069 | |
1070 | mntput(upperpath.mnt); | |
a78d9f0d MS |
1071 | for (i = 0; i < numlower; i++) |
1072 | mntput(stack[i].mnt); | |
e9be9d5e | 1073 | path_put(&workpath); |
a78d9f0d | 1074 | kfree(lowertmp); |
e9be9d5e MS |
1075 | |
1076 | oe->__upperdentry = upperpath.dentry; | |
a78d9f0d MS |
1077 | for (i = 0; i < numlower; i++) { |
1078 | oe->lowerstack[i].dentry = stack[i].dentry; | |
1079 | oe->lowerstack[i].mnt = ufs->lower_mnt[i]; | |
1080 | } | |
0f95502a | 1081 | kfree(stack); |
e9be9d5e MS |
1082 | |
1083 | root_dentry->d_fsdata = oe; | |
1084 | ||
ed06e069 MS |
1085 | ovl_copyattr(ovl_dentry_real(root_dentry)->d_inode, |
1086 | root_dentry->d_inode); | |
1087 | ||
cc259639 | 1088 | sb->s_magic = OVERLAYFS_SUPER_MAGIC; |
e9be9d5e MS |
1089 | sb->s_op = &ovl_super_operations; |
1090 | sb->s_root = root_dentry; | |
1091 | sb->s_fs_info = ufs; | |
1092 | ||
1093 | return 0; | |
1094 | ||
3b7a9a24 MS |
1095 | out_free_oe: |
1096 | kfree(oe); | |
e9be9d5e | 1097 | out_put_lower_mnt: |
dd662667 MS |
1098 | for (i = 0; i < ufs->numlower; i++) |
1099 | mntput(ufs->lower_mnt[i]); | |
1100 | kfree(ufs->lower_mnt); | |
3b7a9a24 MS |
1101 | out_put_workdir: |
1102 | dput(ufs->workdir); | |
e9be9d5e | 1103 | mntput(ufs->upper_mnt); |
e9be9d5e | 1104 | out_put_lowerpath: |
a78d9f0d MS |
1105 | for (i = 0; i < numlower; i++) |
1106 | path_put(&stack[i]); | |
1107 | kfree(stack); | |
1108 | out_free_lowertmp: | |
1109 | kfree(lowertmp); | |
3b7a9a24 MS |
1110 | out_put_workpath: |
1111 | path_put(&workpath); | |
e9be9d5e MS |
1112 | out_put_upperpath: |
1113 | path_put(&upperpath); | |
e9be9d5e | 1114 | out_free_config: |
f45827e8 EZ |
1115 | kfree(ufs->config.lowerdir); |
1116 | kfree(ufs->config.upperdir); | |
1117 | kfree(ufs->config.workdir); | |
1118 | kfree(ufs); | |
e9be9d5e MS |
1119 | out: |
1120 | return err; | |
1121 | } | |
1122 | ||
1123 | static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, | |
1124 | const char *dev_name, void *raw_data) | |
1125 | { | |
1126 | return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); | |
1127 | } | |
1128 | ||
1129 | static struct file_system_type ovl_fs_type = { | |
1130 | .owner = THIS_MODULE, | |
ef94b186 | 1131 | .name = "overlay", |
e9be9d5e MS |
1132 | .mount = ovl_mount, |
1133 | .kill_sb = kill_anon_super, | |
1134 | }; | |
ef94b186 | 1135 | MODULE_ALIAS_FS("overlay"); |
e9be9d5e MS |
1136 | |
1137 | static int __init ovl_init(void) | |
1138 | { | |
1139 | return register_filesystem(&ovl_fs_type); | |
1140 | } | |
1141 | ||
1142 | static void __exit ovl_exit(void) | |
1143 | { | |
1144 | unregister_filesystem(&ovl_fs_type); | |
1145 | } | |
1146 | ||
1147 | module_init(ovl_init); | |
1148 | module_exit(ovl_exit); |