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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> | |
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; | |
3fe6e52f AM |
45 | /* creds of process who forced instantiation of super block */ |
46 | const struct cred *creator_cred; | |
e9be9d5e MS |
47 | }; |
48 | ||
49 | struct ovl_dir_cache; | |
50 | ||
51 | /* private information held for every overlayfs dentry */ | |
52 | struct ovl_entry { | |
53 | struct dentry *__upperdentry; | |
e9be9d5e MS |
54 | struct ovl_dir_cache *cache; |
55 | union { | |
56 | struct { | |
57 | u64 version; | |
58 | bool opaque; | |
59 | }; | |
60 | struct rcu_head rcu; | |
61 | }; | |
dd662667 MS |
62 | unsigned numlower; |
63 | struct path lowerstack[]; | |
e9be9d5e MS |
64 | }; |
65 | ||
a78d9f0d MS |
66 | #define OVL_MAX_STACK 500 |
67 | ||
dd662667 MS |
68 | static struct dentry *__ovl_dentry_lower(struct ovl_entry *oe) |
69 | { | |
70 | return oe->numlower ? oe->lowerstack[0].dentry : NULL; | |
71 | } | |
e9be9d5e MS |
72 | |
73 | enum ovl_path_type ovl_path_type(struct dentry *dentry) | |
74 | { | |
75 | struct ovl_entry *oe = dentry->d_fsdata; | |
1afaba1e | 76 | enum ovl_path_type type = 0; |
e9be9d5e MS |
77 | |
78 | if (oe->__upperdentry) { | |
1afaba1e MS |
79 | type = __OVL_PATH_UPPER; |
80 | ||
45d11738 KK |
81 | /* |
82 | * Non-dir dentry can hold lower dentry from previous | |
83 | * location. Its purity depends only on opaque flag. | |
84 | */ | |
85 | if (oe->numlower && S_ISDIR(dentry->d_inode->i_mode)) | |
86 | type |= __OVL_PATH_MERGE; | |
87 | else if (!oe->opaque) | |
1afaba1e | 88 | type |= __OVL_PATH_PURE; |
9d7459d8 MS |
89 | } else { |
90 | if (oe->numlower > 1) | |
91 | type |= __OVL_PATH_MERGE; | |
e9be9d5e | 92 | } |
1afaba1e | 93 | return type; |
e9be9d5e MS |
94 | } |
95 | ||
96 | static struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe) | |
97 | { | |
71d50928 | 98 | return lockless_dereference(oe->__upperdentry); |
e9be9d5e MS |
99 | } |
100 | ||
101 | void ovl_path_upper(struct dentry *dentry, struct path *path) | |
102 | { | |
103 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
104 | struct ovl_entry *oe = dentry->d_fsdata; | |
105 | ||
106 | path->mnt = ofs->upper_mnt; | |
107 | path->dentry = ovl_upperdentry_dereference(oe); | |
108 | } | |
109 | ||
110 | enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path) | |
111 | { | |
e9be9d5e MS |
112 | enum ovl_path_type type = ovl_path_type(dentry); |
113 | ||
1afaba1e | 114 | if (!OVL_TYPE_UPPER(type)) |
e9be9d5e MS |
115 | ovl_path_lower(dentry, path); |
116 | else | |
117 | ovl_path_upper(dentry, path); | |
118 | ||
119 | return type; | |
120 | } | |
121 | ||
122 | struct dentry *ovl_dentry_upper(struct dentry *dentry) | |
123 | { | |
124 | struct ovl_entry *oe = dentry->d_fsdata; | |
125 | ||
126 | return ovl_upperdentry_dereference(oe); | |
127 | } | |
128 | ||
129 | struct dentry *ovl_dentry_lower(struct dentry *dentry) | |
130 | { | |
131 | struct ovl_entry *oe = dentry->d_fsdata; | |
132 | ||
dd662667 | 133 | return __ovl_dentry_lower(oe); |
e9be9d5e MS |
134 | } |
135 | ||
136 | struct dentry *ovl_dentry_real(struct dentry *dentry) | |
137 | { | |
138 | struct ovl_entry *oe = dentry->d_fsdata; | |
139 | struct dentry *realdentry; | |
140 | ||
141 | realdentry = ovl_upperdentry_dereference(oe); | |
142 | if (!realdentry) | |
dd662667 | 143 | realdentry = __ovl_dentry_lower(oe); |
e9be9d5e MS |
144 | |
145 | return realdentry; | |
146 | } | |
147 | ||
148 | struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper) | |
149 | { | |
150 | struct dentry *realdentry; | |
151 | ||
152 | realdentry = ovl_upperdentry_dereference(oe); | |
153 | if (realdentry) { | |
154 | *is_upper = true; | |
155 | } else { | |
dd662667 | 156 | realdentry = __ovl_dentry_lower(oe); |
e9be9d5e MS |
157 | *is_upper = false; |
158 | } | |
159 | return realdentry; | |
160 | } | |
161 | ||
8d3095f4 MS |
162 | struct vfsmount *ovl_entry_mnt_real(struct ovl_entry *oe, struct inode *inode, |
163 | bool is_upper) | |
164 | { | |
165 | if (is_upper) { | |
166 | struct ovl_fs *ofs = inode->i_sb->s_fs_info; | |
167 | ||
168 | return ofs->upper_mnt; | |
169 | } else { | |
170 | return oe->numlower ? oe->lowerstack[0].mnt : NULL; | |
171 | } | |
172 | } | |
173 | ||
e9be9d5e MS |
174 | struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry) |
175 | { | |
176 | struct ovl_entry *oe = dentry->d_fsdata; | |
177 | ||
178 | return oe->cache; | |
179 | } | |
180 | ||
8d3095f4 MS |
181 | bool ovl_is_default_permissions(struct inode *inode) |
182 | { | |
183 | struct ovl_fs *ofs = inode->i_sb->s_fs_info; | |
184 | ||
185 | return ofs->config.default_permissions; | |
186 | } | |
187 | ||
e9be9d5e MS |
188 | void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache) |
189 | { | |
190 | struct ovl_entry *oe = dentry->d_fsdata; | |
191 | ||
192 | oe->cache = cache; | |
193 | } | |
194 | ||
195 | void ovl_path_lower(struct dentry *dentry, struct path *path) | |
196 | { | |
e9be9d5e MS |
197 | struct ovl_entry *oe = dentry->d_fsdata; |
198 | ||
dd662667 | 199 | *path = oe->numlower ? oe->lowerstack[0] : (struct path) { NULL, NULL }; |
e9be9d5e MS |
200 | } |
201 | ||
202 | int ovl_want_write(struct dentry *dentry) | |
203 | { | |
204 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
205 | return mnt_want_write(ofs->upper_mnt); | |
206 | } | |
207 | ||
208 | void ovl_drop_write(struct dentry *dentry) | |
209 | { | |
210 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
211 | mnt_drop_write(ofs->upper_mnt); | |
212 | } | |
213 | ||
214 | struct dentry *ovl_workdir(struct dentry *dentry) | |
215 | { | |
216 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
217 | return ofs->workdir; | |
218 | } | |
219 | ||
220 | bool ovl_dentry_is_opaque(struct dentry *dentry) | |
221 | { | |
222 | struct ovl_entry *oe = dentry->d_fsdata; | |
223 | return oe->opaque; | |
224 | } | |
225 | ||
226 | void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque) | |
227 | { | |
228 | struct ovl_entry *oe = dentry->d_fsdata; | |
229 | oe->opaque = opaque; | |
230 | } | |
231 | ||
232 | void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry) | |
233 | { | |
234 | struct ovl_entry *oe = dentry->d_fsdata; | |
235 | ||
5955102c | 236 | WARN_ON(!inode_is_locked(upperdentry->d_parent->d_inode)); |
e9be9d5e MS |
237 | WARN_ON(oe->__upperdentry); |
238 | BUG_ON(!upperdentry->d_inode); | |
239 | /* | |
240 | * Make sure upperdentry is consistent before making it visible to | |
241 | * ovl_upperdentry_dereference(). | |
242 | */ | |
243 | smp_wmb(); | |
244 | oe->__upperdentry = upperdentry; | |
245 | } | |
246 | ||
247 | void ovl_dentry_version_inc(struct dentry *dentry) | |
248 | { | |
249 | struct ovl_entry *oe = dentry->d_fsdata; | |
250 | ||
5955102c | 251 | WARN_ON(!inode_is_locked(dentry->d_inode)); |
e9be9d5e MS |
252 | oe->version++; |
253 | } | |
254 | ||
255 | u64 ovl_dentry_version_get(struct dentry *dentry) | |
256 | { | |
257 | struct ovl_entry *oe = dentry->d_fsdata; | |
258 | ||
5955102c | 259 | WARN_ON(!inode_is_locked(dentry->d_inode)); |
e9be9d5e MS |
260 | return oe->version; |
261 | } | |
262 | ||
263 | bool ovl_is_whiteout(struct dentry *dentry) | |
264 | { | |
265 | struct inode *inode = dentry->d_inode; | |
266 | ||
267 | return inode && IS_WHITEOUT(inode); | |
268 | } | |
269 | ||
3fe6e52f AM |
270 | const struct cred *ovl_override_creds(struct super_block *sb) |
271 | { | |
272 | struct ovl_fs *ofs = sb->s_fs_info; | |
273 | ||
274 | return override_creds(ofs->creator_cred); | |
275 | } | |
276 | ||
e9be9d5e MS |
277 | static bool ovl_is_opaquedir(struct dentry *dentry) |
278 | { | |
279 | int res; | |
280 | char val; | |
281 | struct inode *inode = dentry->d_inode; | |
282 | ||
283 | if (!S_ISDIR(inode->i_mode) || !inode->i_op->getxattr) | |
284 | return false; | |
285 | ||
ce23e640 | 286 | res = inode->i_op->getxattr(dentry, inode, OVL_XATTR_OPAQUE, &val, 1); |
e9be9d5e MS |
287 | if (res == 1 && val == 'y') |
288 | return true; | |
289 | ||
290 | return false; | |
291 | } | |
292 | ||
293 | static void ovl_dentry_release(struct dentry *dentry) | |
294 | { | |
295 | struct ovl_entry *oe = dentry->d_fsdata; | |
296 | ||
297 | if (oe) { | |
dd662667 MS |
298 | unsigned int i; |
299 | ||
e9be9d5e | 300 | dput(oe->__upperdentry); |
dd662667 MS |
301 | for (i = 0; i < oe->numlower; i++) |
302 | dput(oe->lowerstack[i].dentry); | |
e9be9d5e MS |
303 | kfree_rcu(oe, rcu); |
304 | } | |
305 | } | |
306 | ||
d101a125 MS |
307 | static struct dentry *ovl_d_real(struct dentry *dentry, struct inode *inode) |
308 | { | |
309 | struct dentry *real; | |
310 | ||
311 | if (d_is_dir(dentry)) { | |
312 | if (!inode || inode == d_inode(dentry)) | |
313 | return dentry; | |
314 | goto bug; | |
315 | } | |
316 | ||
317 | real = ovl_dentry_upper(dentry); | |
318 | if (real && (!inode || inode == d_inode(real))) | |
319 | return real; | |
320 | ||
321 | real = ovl_dentry_lower(dentry); | |
322 | if (!real) | |
323 | goto bug; | |
324 | ||
325 | if (!inode || inode == d_inode(real)) | |
326 | return real; | |
327 | ||
328 | /* Handle recursion */ | |
329 | if (real->d_flags & DCACHE_OP_REAL) | |
330 | return real->d_op->d_real(real, inode); | |
331 | ||
332 | bug: | |
333 | WARN(1, "ovl_d_real(%pd4, %s:%lu\n): real dentry not found\n", dentry, | |
334 | inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0); | |
335 | return dentry; | |
336 | } | |
337 | ||
7c03b5d4 MS |
338 | static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) |
339 | { | |
340 | struct ovl_entry *oe = dentry->d_fsdata; | |
341 | unsigned int i; | |
342 | int ret = 1; | |
343 | ||
344 | for (i = 0; i < oe->numlower; i++) { | |
345 | struct dentry *d = oe->lowerstack[i].dentry; | |
346 | ||
347 | if (d->d_flags & DCACHE_OP_REVALIDATE) { | |
348 | ret = d->d_op->d_revalidate(d, flags); | |
349 | if (ret < 0) | |
350 | return ret; | |
351 | if (!ret) { | |
352 | if (!(flags & LOOKUP_RCU)) | |
353 | d_invalidate(d); | |
354 | return -ESTALE; | |
355 | } | |
356 | } | |
357 | } | |
358 | return 1; | |
359 | } | |
360 | ||
361 | static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) | |
362 | { | |
363 | struct ovl_entry *oe = dentry->d_fsdata; | |
364 | unsigned int i; | |
365 | int ret = 1; | |
366 | ||
367 | for (i = 0; i < oe->numlower; i++) { | |
368 | struct dentry *d = oe->lowerstack[i].dentry; | |
369 | ||
370 | if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) { | |
371 | ret = d->d_op->d_weak_revalidate(d, flags); | |
372 | if (ret <= 0) | |
373 | break; | |
374 | } | |
375 | } | |
376 | return ret; | |
377 | } | |
378 | ||
e9be9d5e MS |
379 | static const struct dentry_operations ovl_dentry_operations = { |
380 | .d_release = ovl_dentry_release, | |
4bacc9c9 | 381 | .d_select_inode = ovl_d_select_inode, |
d101a125 | 382 | .d_real = ovl_d_real, |
e9be9d5e MS |
383 | }; |
384 | ||
7c03b5d4 MS |
385 | static const struct dentry_operations ovl_reval_dentry_operations = { |
386 | .d_release = ovl_dentry_release, | |
b5891cfa | 387 | .d_select_inode = ovl_d_select_inode, |
d101a125 | 388 | .d_real = ovl_d_real, |
7c03b5d4 MS |
389 | .d_revalidate = ovl_dentry_revalidate, |
390 | .d_weak_revalidate = ovl_dentry_weak_revalidate, | |
391 | }; | |
392 | ||
dd662667 | 393 | static struct ovl_entry *ovl_alloc_entry(unsigned int numlower) |
e9be9d5e | 394 | { |
dd662667 MS |
395 | size_t size = offsetof(struct ovl_entry, lowerstack[numlower]); |
396 | struct ovl_entry *oe = kzalloc(size, GFP_KERNEL); | |
397 | ||
398 | if (oe) | |
399 | oe->numlower = numlower; | |
400 | ||
401 | return oe; | |
e9be9d5e MS |
402 | } |
403 | ||
7c03b5d4 MS |
404 | static bool ovl_dentry_remote(struct dentry *dentry) |
405 | { | |
406 | return dentry->d_flags & | |
407 | (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE); | |
408 | } | |
409 | ||
410 | static bool ovl_dentry_weird(struct dentry *dentry) | |
411 | { | |
412 | return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT | | |
413 | DCACHE_MANAGE_TRANSIT | | |
414 | DCACHE_OP_HASH | | |
415 | DCACHE_OP_COMPARE); | |
416 | } | |
417 | ||
e9be9d5e MS |
418 | static inline struct dentry *ovl_lookup_real(struct dentry *dir, |
419 | struct qstr *name) | |
420 | { | |
421 | struct dentry *dentry; | |
422 | ||
38b78a5f | 423 | dentry = lookup_hash(name, dir); |
e9be9d5e MS |
424 | |
425 | if (IS_ERR(dentry)) { | |
426 | if (PTR_ERR(dentry) == -ENOENT) | |
427 | dentry = NULL; | |
428 | } else if (!dentry->d_inode) { | |
429 | dput(dentry); | |
430 | dentry = NULL; | |
7c03b5d4 | 431 | } else if (ovl_dentry_weird(dentry)) { |
a6f15d9a | 432 | dput(dentry); |
7c03b5d4 | 433 | /* Don't support traversing automounts and other weirdness */ |
a6f15d9a | 434 | dentry = ERR_PTR(-EREMOTE); |
e9be9d5e MS |
435 | } |
436 | return dentry; | |
437 | } | |
438 | ||
5ef88da5 MS |
439 | /* |
440 | * Returns next layer in stack starting from top. | |
441 | * Returns -1 if this is the last layer. | |
442 | */ | |
443 | int ovl_path_next(int idx, struct dentry *dentry, struct path *path) | |
444 | { | |
445 | struct ovl_entry *oe = dentry->d_fsdata; | |
446 | ||
447 | BUG_ON(idx < 0); | |
448 | if (idx == 0) { | |
449 | ovl_path_upper(dentry, path); | |
450 | if (path->dentry) | |
451 | return oe->numlower ? 1 : -1; | |
452 | idx++; | |
453 | } | |
454 | BUG_ON(idx > oe->numlower); | |
455 | *path = oe->lowerstack[idx - 1]; | |
456 | ||
457 | return (idx < oe->numlower) ? idx + 1 : -1; | |
458 | } | |
459 | ||
e9be9d5e MS |
460 | struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, |
461 | unsigned int flags) | |
462 | { | |
463 | struct ovl_entry *oe; | |
3d3c6b89 MS |
464 | struct ovl_entry *poe = dentry->d_parent->d_fsdata; |
465 | struct path *stack = NULL; | |
466 | struct dentry *upperdir, *upperdentry = NULL; | |
467 | unsigned int ctr = 0; | |
e9be9d5e | 468 | struct inode *inode = NULL; |
3d3c6b89 MS |
469 | bool upperopaque = false; |
470 | struct dentry *this, *prev = NULL; | |
471 | unsigned int i; | |
e9be9d5e MS |
472 | int err; |
473 | ||
3d3c6b89 | 474 | upperdir = ovl_upperdentry_dereference(poe); |
e9be9d5e | 475 | if (upperdir) { |
3d3c6b89 MS |
476 | this = ovl_lookup_real(upperdir, &dentry->d_name); |
477 | err = PTR_ERR(this); | |
478 | if (IS_ERR(this)) | |
479 | goto out; | |
480 | ||
3e01cee3 | 481 | if (this) { |
7c03b5d4 MS |
482 | if (unlikely(ovl_dentry_remote(this))) { |
483 | dput(this); | |
484 | err = -EREMOTE; | |
485 | goto out; | |
486 | } | |
3d3c6b89 MS |
487 | if (ovl_is_whiteout(this)) { |
488 | dput(this); | |
489 | this = NULL; | |
490 | upperopaque = true; | |
3e01cee3 | 491 | } else if (poe->numlower && ovl_is_opaquedir(this)) { |
3d3c6b89 | 492 | upperopaque = true; |
e9be9d5e MS |
493 | } |
494 | } | |
3d3c6b89 | 495 | upperdentry = prev = this; |
e9be9d5e | 496 | } |
3d3c6b89 MS |
497 | |
498 | if (!upperopaque && poe->numlower) { | |
499 | err = -ENOMEM; | |
500 | stack = kcalloc(poe->numlower, sizeof(struct path), GFP_KERNEL); | |
501 | if (!stack) | |
502 | goto out_put_upper; | |
e9be9d5e MS |
503 | } |
504 | ||
3d3c6b89 MS |
505 | for (i = 0; !upperopaque && i < poe->numlower; i++) { |
506 | bool opaque = false; | |
507 | struct path lowerpath = poe->lowerstack[i]; | |
508 | ||
3d3c6b89 MS |
509 | this = ovl_lookup_real(lowerpath.dentry, &dentry->d_name); |
510 | err = PTR_ERR(this); | |
09e10322 MS |
511 | if (IS_ERR(this)) { |
512 | /* | |
513 | * If it's positive, then treat ENAMETOOLONG as ENOENT. | |
514 | */ | |
515 | if (err == -ENAMETOOLONG && (upperdentry || ctr)) | |
516 | continue; | |
3d3c6b89 | 517 | goto out_put; |
09e10322 | 518 | } |
3d3c6b89 MS |
519 | if (!this) |
520 | continue; | |
3e01cee3 MS |
521 | if (ovl_is_whiteout(this)) { |
522 | dput(this); | |
523 | break; | |
524 | } | |
3d3c6b89 | 525 | /* |
3e01cee3 MS |
526 | * Only makes sense to check opaque dir if this is not the |
527 | * lowermost layer. | |
3d3c6b89 | 528 | */ |
3e01cee3 MS |
529 | if (i < poe->numlower - 1 && ovl_is_opaquedir(this)) |
530 | opaque = true; | |
a425c037 | 531 | |
532 | if (prev && (!S_ISDIR(prev->d_inode->i_mode) || | |
533 | !S_ISDIR(this->d_inode->i_mode))) { | |
534 | /* | |
535 | * FIXME: check for upper-opaqueness maybe better done | |
536 | * in remove code. | |
537 | */ | |
3d3c6b89 MS |
538 | if (prev == upperdentry) |
539 | upperopaque = true; | |
540 | dput(this); | |
541 | break; | |
542 | } | |
a425c037 | 543 | /* |
544 | * If this is a non-directory then stop here. | |
545 | */ | |
546 | if (!S_ISDIR(this->d_inode->i_mode)) | |
547 | opaque = true; | |
548 | ||
3d3c6b89 MS |
549 | stack[ctr].dentry = this; |
550 | stack[ctr].mnt = lowerpath.mnt; | |
551 | ctr++; | |
552 | prev = this; | |
553 | if (opaque) | |
554 | break; | |
e9be9d5e MS |
555 | } |
556 | ||
3d3c6b89 MS |
557 | oe = ovl_alloc_entry(ctr); |
558 | err = -ENOMEM; | |
559 | if (!oe) | |
560 | goto out_put; | |
561 | ||
562 | if (upperdentry || ctr) { | |
e9be9d5e MS |
563 | struct dentry *realdentry; |
564 | ||
3d3c6b89 MS |
565 | realdentry = upperdentry ? upperdentry : stack[0].dentry; |
566 | ||
e9be9d5e MS |
567 | err = -ENOMEM; |
568 | inode = ovl_new_inode(dentry->d_sb, realdentry->d_inode->i_mode, | |
569 | oe); | |
570 | if (!inode) | |
3d3c6b89 | 571 | goto out_free_oe; |
e9be9d5e MS |
572 | ovl_copyattr(realdentry->d_inode, inode); |
573 | } | |
574 | ||
3d3c6b89 | 575 | oe->opaque = upperopaque; |
e9be9d5e | 576 | oe->__upperdentry = upperdentry; |
3d3c6b89 MS |
577 | memcpy(oe->lowerstack, stack, sizeof(struct path) * ctr); |
578 | kfree(stack); | |
e9be9d5e MS |
579 | dentry->d_fsdata = oe; |
580 | d_add(dentry, inode); | |
581 | ||
582 | return NULL; | |
583 | ||
3d3c6b89 | 584 | out_free_oe: |
e9be9d5e | 585 | kfree(oe); |
3d3c6b89 MS |
586 | out_put: |
587 | for (i = 0; i < ctr; i++) | |
588 | dput(stack[i].dentry); | |
589 | kfree(stack); | |
590 | out_put_upper: | |
591 | dput(upperdentry); | |
e9be9d5e MS |
592 | out: |
593 | return ERR_PTR(err); | |
594 | } | |
595 | ||
596 | struct file *ovl_path_open(struct path *path, int flags) | |
597 | { | |
598 | return dentry_open(path, flags, current_cred()); | |
599 | } | |
600 | ||
601 | static void ovl_put_super(struct super_block *sb) | |
602 | { | |
603 | struct ovl_fs *ufs = sb->s_fs_info; | |
dd662667 | 604 | unsigned i; |
e9be9d5e MS |
605 | |
606 | dput(ufs->workdir); | |
607 | mntput(ufs->upper_mnt); | |
dd662667 MS |
608 | for (i = 0; i < ufs->numlower; i++) |
609 | mntput(ufs->lower_mnt[i]); | |
5ffdbe8b | 610 | kfree(ufs->lower_mnt); |
e9be9d5e | 611 | |
f45827e8 EZ |
612 | kfree(ufs->config.lowerdir); |
613 | kfree(ufs->config.upperdir); | |
614 | kfree(ufs->config.workdir); | |
3fe6e52f | 615 | put_cred(ufs->creator_cred); |
e9be9d5e MS |
616 | kfree(ufs); |
617 | } | |
618 | ||
cc259639 AW |
619 | /** |
620 | * ovl_statfs | |
621 | * @sb: The overlayfs super block | |
622 | * @buf: The struct kstatfs to fill in with stats | |
623 | * | |
624 | * Get the filesystem statistics. As writes always target the upper layer | |
4ebc5818 | 625 | * filesystem pass the statfs to the upper filesystem (if it exists) |
cc259639 AW |
626 | */ |
627 | static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) | |
628 | { | |
629 | struct ovl_fs *ofs = dentry->d_sb->s_fs_info; | |
630 | struct dentry *root_dentry = dentry->d_sb->s_root; | |
631 | struct path path; | |
632 | int err; | |
633 | ||
4ebc5818 | 634 | ovl_path_real(root_dentry, &path); |
cc259639 AW |
635 | |
636 | err = vfs_statfs(&path, buf); | |
637 | if (!err) { | |
638 | buf->f_namelen = max(buf->f_namelen, ofs->lower_namelen); | |
639 | buf->f_type = OVERLAYFS_SUPER_MAGIC; | |
640 | } | |
641 | ||
642 | return err; | |
643 | } | |
644 | ||
f45827e8 EZ |
645 | /** |
646 | * ovl_show_options | |
647 | * | |
648 | * Prints the mount options for a given superblock. | |
649 | * Returns zero; does not fail. | |
650 | */ | |
651 | static int ovl_show_options(struct seq_file *m, struct dentry *dentry) | |
652 | { | |
653 | struct super_block *sb = dentry->d_sb; | |
654 | struct ovl_fs *ufs = sb->s_fs_info; | |
655 | ||
a068acf2 | 656 | seq_show_option(m, "lowerdir", ufs->config.lowerdir); |
53a08cb9 | 657 | if (ufs->config.upperdir) { |
a068acf2 KC |
658 | seq_show_option(m, "upperdir", ufs->config.upperdir); |
659 | seq_show_option(m, "workdir", ufs->config.workdir); | |
53a08cb9 | 660 | } |
8d3095f4 MS |
661 | if (ufs->config.default_permissions) |
662 | seq_puts(m, ",default_permissions"); | |
f45827e8 EZ |
663 | return 0; |
664 | } | |
665 | ||
3cdf6fe9 SL |
666 | static int ovl_remount(struct super_block *sb, int *flags, char *data) |
667 | { | |
668 | struct ovl_fs *ufs = sb->s_fs_info; | |
669 | ||
cc6f67bc | 670 | if (!(*flags & MS_RDONLY) && (!ufs->upper_mnt || !ufs->workdir)) |
3cdf6fe9 SL |
671 | return -EROFS; |
672 | ||
673 | return 0; | |
674 | } | |
675 | ||
e9be9d5e MS |
676 | static const struct super_operations ovl_super_operations = { |
677 | .put_super = ovl_put_super, | |
cc259639 | 678 | .statfs = ovl_statfs, |
f45827e8 | 679 | .show_options = ovl_show_options, |
3cdf6fe9 | 680 | .remount_fs = ovl_remount, |
e9be9d5e MS |
681 | }; |
682 | ||
683 | enum { | |
684 | OPT_LOWERDIR, | |
685 | OPT_UPPERDIR, | |
686 | OPT_WORKDIR, | |
8d3095f4 | 687 | OPT_DEFAULT_PERMISSIONS, |
e9be9d5e MS |
688 | OPT_ERR, |
689 | }; | |
690 | ||
691 | static const match_table_t ovl_tokens = { | |
692 | {OPT_LOWERDIR, "lowerdir=%s"}, | |
693 | {OPT_UPPERDIR, "upperdir=%s"}, | |
694 | {OPT_WORKDIR, "workdir=%s"}, | |
8d3095f4 | 695 | {OPT_DEFAULT_PERMISSIONS, "default_permissions"}, |
e9be9d5e MS |
696 | {OPT_ERR, NULL} |
697 | }; | |
698 | ||
91c77947 MS |
699 | static char *ovl_next_opt(char **s) |
700 | { | |
701 | char *sbegin = *s; | |
702 | char *p; | |
703 | ||
704 | if (sbegin == NULL) | |
705 | return NULL; | |
706 | ||
707 | for (p = sbegin; *p; p++) { | |
708 | if (*p == '\\') { | |
709 | p++; | |
710 | if (!*p) | |
711 | break; | |
712 | } else if (*p == ',') { | |
713 | *p = '\0'; | |
714 | *s = p + 1; | |
715 | return sbegin; | |
716 | } | |
717 | } | |
718 | *s = NULL; | |
719 | return sbegin; | |
720 | } | |
721 | ||
e9be9d5e MS |
722 | static int ovl_parse_opt(char *opt, struct ovl_config *config) |
723 | { | |
724 | char *p; | |
725 | ||
91c77947 | 726 | while ((p = ovl_next_opt(&opt)) != NULL) { |
e9be9d5e MS |
727 | int token; |
728 | substring_t args[MAX_OPT_ARGS]; | |
729 | ||
730 | if (!*p) | |
731 | continue; | |
732 | ||
733 | token = match_token(p, ovl_tokens, args); | |
734 | switch (token) { | |
735 | case OPT_UPPERDIR: | |
736 | kfree(config->upperdir); | |
737 | config->upperdir = match_strdup(&args[0]); | |
738 | if (!config->upperdir) | |
739 | return -ENOMEM; | |
740 | break; | |
741 | ||
742 | case OPT_LOWERDIR: | |
743 | kfree(config->lowerdir); | |
744 | config->lowerdir = match_strdup(&args[0]); | |
745 | if (!config->lowerdir) | |
746 | return -ENOMEM; | |
747 | break; | |
748 | ||
749 | case OPT_WORKDIR: | |
750 | kfree(config->workdir); | |
751 | config->workdir = match_strdup(&args[0]); | |
752 | if (!config->workdir) | |
753 | return -ENOMEM; | |
754 | break; | |
755 | ||
8d3095f4 MS |
756 | case OPT_DEFAULT_PERMISSIONS: |
757 | config->default_permissions = true; | |
758 | break; | |
759 | ||
e9be9d5e | 760 | default: |
bead55ef | 761 | pr_err("overlayfs: unrecognized mount option \"%s\" or missing value\n", p); |
e9be9d5e MS |
762 | return -EINVAL; |
763 | } | |
764 | } | |
71cbad7e | 765 | |
766 | /* Workdir is useless in non-upper mount */ | |
767 | if (!config->upperdir && config->workdir) { | |
768 | pr_info("overlayfs: option \"workdir=%s\" is useless in a non-upper mount, ignore\n", | |
769 | config->workdir); | |
770 | kfree(config->workdir); | |
771 | config->workdir = NULL; | |
772 | } | |
773 | ||
e9be9d5e MS |
774 | return 0; |
775 | } | |
776 | ||
777 | #define OVL_WORKDIR_NAME "work" | |
778 | ||
779 | static struct dentry *ovl_workdir_create(struct vfsmount *mnt, | |
780 | struct dentry *dentry) | |
781 | { | |
782 | struct inode *dir = dentry->d_inode; | |
783 | struct dentry *work; | |
784 | int err; | |
785 | bool retried = false; | |
786 | ||
787 | err = mnt_want_write(mnt); | |
788 | if (err) | |
789 | return ERR_PTR(err); | |
790 | ||
5955102c | 791 | inode_lock_nested(dir, I_MUTEX_PARENT); |
e9be9d5e MS |
792 | retry: |
793 | work = lookup_one_len(OVL_WORKDIR_NAME, dentry, | |
794 | strlen(OVL_WORKDIR_NAME)); | |
795 | ||
796 | if (!IS_ERR(work)) { | |
797 | struct kstat stat = { | |
798 | .mode = S_IFDIR | 0, | |
799 | }; | |
800 | ||
801 | if (work->d_inode) { | |
802 | err = -EEXIST; | |
803 | if (retried) | |
804 | goto out_dput; | |
805 | ||
806 | retried = true; | |
807 | ovl_cleanup(dir, work); | |
808 | dput(work); | |
809 | goto retry; | |
810 | } | |
811 | ||
812 | err = ovl_create_real(dir, work, &stat, NULL, NULL, true); | |
813 | if (err) | |
814 | goto out_dput; | |
815 | } | |
816 | out_unlock: | |
5955102c | 817 | inode_unlock(dir); |
e9be9d5e MS |
818 | mnt_drop_write(mnt); |
819 | ||
820 | return work; | |
821 | ||
822 | out_dput: | |
823 | dput(work); | |
824 | work = ERR_PTR(err); | |
825 | goto out_unlock; | |
826 | } | |
827 | ||
91c77947 MS |
828 | static void ovl_unescape(char *s) |
829 | { | |
830 | char *d = s; | |
831 | ||
832 | for (;; s++, d++) { | |
833 | if (*s == '\\') | |
834 | s++; | |
835 | *d = *s; | |
836 | if (!*s) | |
837 | break; | |
838 | } | |
839 | } | |
840 | ||
ab508822 MS |
841 | static int ovl_mount_dir_noesc(const char *name, struct path *path) |
842 | { | |
a78d9f0d | 843 | int err = -EINVAL; |
ab508822 | 844 | |
a78d9f0d MS |
845 | if (!*name) { |
846 | pr_err("overlayfs: empty lowerdir\n"); | |
847 | goto out; | |
848 | } | |
ab508822 MS |
849 | err = kern_path(name, LOOKUP_FOLLOW, path); |
850 | if (err) { | |
851 | pr_err("overlayfs: failed to resolve '%s': %i\n", name, err); | |
852 | goto out; | |
853 | } | |
854 | err = -EINVAL; | |
7c03b5d4 | 855 | if (ovl_dentry_weird(path->dentry)) { |
ab508822 MS |
856 | pr_err("overlayfs: filesystem on '%s' not supported\n", name); |
857 | goto out_put; | |
858 | } | |
859 | if (!S_ISDIR(path->dentry->d_inode->i_mode)) { | |
860 | pr_err("overlayfs: '%s' not a directory\n", name); | |
861 | goto out_put; | |
862 | } | |
863 | return 0; | |
864 | ||
865 | out_put: | |
866 | path_put(path); | |
867 | out: | |
868 | return err; | |
869 | } | |
870 | ||
871 | static int ovl_mount_dir(const char *name, struct path *path) | |
872 | { | |
873 | int err = -ENOMEM; | |
874 | char *tmp = kstrdup(name, GFP_KERNEL); | |
875 | ||
876 | if (tmp) { | |
877 | ovl_unescape(tmp); | |
878 | err = ovl_mount_dir_noesc(tmp, path); | |
7c03b5d4 MS |
879 | |
880 | if (!err) | |
881 | if (ovl_dentry_remote(path->dentry)) { | |
882 | pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n", | |
883 | tmp); | |
884 | path_put(path); | |
885 | err = -EINVAL; | |
886 | } | |
ab508822 MS |
887 | kfree(tmp); |
888 | } | |
889 | return err; | |
890 | } | |
891 | ||
892 | static int ovl_lower_dir(const char *name, struct path *path, long *namelen, | |
7c03b5d4 | 893 | int *stack_depth, bool *remote) |
ab508822 MS |
894 | { |
895 | int err; | |
896 | struct kstatfs statfs; | |
897 | ||
a78d9f0d | 898 | err = ovl_mount_dir_noesc(name, path); |
ab508822 MS |
899 | if (err) |
900 | goto out; | |
901 | ||
902 | err = vfs_statfs(path, &statfs); | |
903 | if (err) { | |
904 | pr_err("overlayfs: statfs failed on '%s'\n", name); | |
905 | goto out_put; | |
906 | } | |
907 | *namelen = max(*namelen, statfs.f_namelen); | |
908 | *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); | |
909 | ||
7c03b5d4 MS |
910 | if (ovl_dentry_remote(path->dentry)) |
911 | *remote = true; | |
912 | ||
ab508822 MS |
913 | return 0; |
914 | ||
915 | out_put: | |
916 | path_put(path); | |
917 | out: | |
918 | return err; | |
919 | } | |
920 | ||
e9be9d5e MS |
921 | /* Workdir should not be subdir of upperdir and vice versa */ |
922 | static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir) | |
923 | { | |
924 | bool ok = false; | |
925 | ||
926 | if (workdir != upperdir) { | |
927 | ok = (lock_rename(workdir, upperdir) == NULL); | |
928 | unlock_rename(workdir, upperdir); | |
929 | } | |
930 | return ok; | |
931 | } | |
932 | ||
a78d9f0d MS |
933 | static unsigned int ovl_split_lowerdirs(char *str) |
934 | { | |
935 | unsigned int ctr = 1; | |
936 | char *s, *d; | |
937 | ||
938 | for (s = d = str;; s++, d++) { | |
939 | if (*s == '\\') { | |
940 | s++; | |
941 | } else if (*s == ':') { | |
942 | *d = '\0'; | |
943 | ctr++; | |
944 | continue; | |
945 | } | |
946 | *d = *s; | |
947 | if (!*s) | |
948 | break; | |
949 | } | |
950 | return ctr; | |
951 | } | |
952 | ||
e9be9d5e MS |
953 | static int ovl_fill_super(struct super_block *sb, void *data, int silent) |
954 | { | |
53a08cb9 MS |
955 | struct path upperpath = { NULL, NULL }; |
956 | struct path workpath = { NULL, NULL }; | |
e9be9d5e MS |
957 | struct dentry *root_dentry; |
958 | struct ovl_entry *oe; | |
959 | struct ovl_fs *ufs; | |
a78d9f0d MS |
960 | struct path *stack = NULL; |
961 | char *lowertmp; | |
962 | char *lower; | |
963 | unsigned int numlower; | |
964 | unsigned int stacklen = 0; | |
dd662667 | 965 | unsigned int i; |
7c03b5d4 | 966 | bool remote = false; |
e9be9d5e MS |
967 | int err; |
968 | ||
f45827e8 EZ |
969 | err = -ENOMEM; |
970 | ufs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); | |
971 | if (!ufs) | |
e9be9d5e MS |
972 | goto out; |
973 | ||
f45827e8 EZ |
974 | err = ovl_parse_opt((char *) data, &ufs->config); |
975 | if (err) | |
976 | goto out_free_config; | |
977 | ||
e9be9d5e | 978 | err = -EINVAL; |
53a08cb9 | 979 | if (!ufs->config.lowerdir) { |
07f2af7b KK |
980 | if (!silent) |
981 | pr_err("overlayfs: missing 'lowerdir'\n"); | |
e9be9d5e MS |
982 | goto out_free_config; |
983 | } | |
984 | ||
53a08cb9 | 985 | sb->s_stack_depth = 0; |
cf9a6784 | 986 | sb->s_maxbytes = MAX_LFS_FILESIZE; |
53a08cb9 | 987 | if (ufs->config.upperdir) { |
53a08cb9 MS |
988 | if (!ufs->config.workdir) { |
989 | pr_err("overlayfs: missing 'workdir'\n"); | |
990 | goto out_free_config; | |
991 | } | |
e9be9d5e | 992 | |
53a08cb9 MS |
993 | err = ovl_mount_dir(ufs->config.upperdir, &upperpath); |
994 | if (err) | |
995 | goto out_free_config; | |
e9be9d5e | 996 | |
71cbad7e | 997 | /* Upper fs should not be r/o */ |
998 | if (upperpath.mnt->mnt_sb->s_flags & MS_RDONLY) { | |
999 | pr_err("overlayfs: upper fs is r/o, try multi-lower layers mount\n"); | |
1000 | err = -EINVAL; | |
1001 | goto out_put_upperpath; | |
1002 | } | |
1003 | ||
53a08cb9 MS |
1004 | err = ovl_mount_dir(ufs->config.workdir, &workpath); |
1005 | if (err) | |
1006 | goto out_put_upperpath; | |
1007 | ||
2f83fd8c | 1008 | err = -EINVAL; |
53a08cb9 MS |
1009 | if (upperpath.mnt != workpath.mnt) { |
1010 | pr_err("overlayfs: workdir and upperdir must reside under the same mount\n"); | |
1011 | goto out_put_workpath; | |
1012 | } | |
1013 | if (!ovl_workdir_ok(workpath.dentry, upperpath.dentry)) { | |
1014 | pr_err("overlayfs: workdir and upperdir must be separate subtrees\n"); | |
1015 | goto out_put_workpath; | |
1016 | } | |
1017 | sb->s_stack_depth = upperpath.mnt->mnt_sb->s_stack_depth; | |
cc259639 | 1018 | } |
a78d9f0d MS |
1019 | err = -ENOMEM; |
1020 | lowertmp = kstrdup(ufs->config.lowerdir, GFP_KERNEL); | |
1021 | if (!lowertmp) | |
ab508822 | 1022 | goto out_put_workpath; |
69c433ed | 1023 | |
a78d9f0d MS |
1024 | err = -EINVAL; |
1025 | stacklen = ovl_split_lowerdirs(lowertmp); | |
6be4506e | 1026 | if (stacklen > OVL_MAX_STACK) { |
1027 | pr_err("overlayfs: too many lower directries, limit is %d\n", | |
1028 | OVL_MAX_STACK); | |
a78d9f0d | 1029 | goto out_free_lowertmp; |
6be4506e | 1030 | } else if (!ufs->config.upperdir && stacklen == 1) { |
1031 | pr_err("overlayfs: at least 2 lowerdir are needed while upperdir nonexistent\n"); | |
1032 | goto out_free_lowertmp; | |
1033 | } | |
a78d9f0d MS |
1034 | |
1035 | stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL); | |
1036 | if (!stack) | |
1037 | goto out_free_lowertmp; | |
1038 | ||
1039 | lower = lowertmp; | |
1040 | for (numlower = 0; numlower < stacklen; numlower++) { | |
1041 | err = ovl_lower_dir(lower, &stack[numlower], | |
7c03b5d4 MS |
1042 | &ufs->lower_namelen, &sb->s_stack_depth, |
1043 | &remote); | |
a78d9f0d MS |
1044 | if (err) |
1045 | goto out_put_lowerpath; | |
1046 | ||
1047 | lower = strchr(lower, '\0') + 1; | |
1048 | } | |
1049 | ||
69c433ed | 1050 | err = -EINVAL; |
ab508822 | 1051 | sb->s_stack_depth++; |
69c433ed MS |
1052 | if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) { |
1053 | pr_err("overlayfs: maximum fs stacking depth exceeded\n"); | |
3b7a9a24 | 1054 | goto out_put_lowerpath; |
69c433ed MS |
1055 | } |
1056 | ||
53a08cb9 MS |
1057 | if (ufs->config.upperdir) { |
1058 | ufs->upper_mnt = clone_private_mount(&upperpath); | |
1059 | err = PTR_ERR(ufs->upper_mnt); | |
1060 | if (IS_ERR(ufs->upper_mnt)) { | |
1061 | pr_err("overlayfs: failed to clone upperpath\n"); | |
1062 | goto out_put_lowerpath; | |
1063 | } | |
3b7a9a24 | 1064 | |
53a08cb9 MS |
1065 | ufs->workdir = ovl_workdir_create(ufs->upper_mnt, workpath.dentry); |
1066 | err = PTR_ERR(ufs->workdir); | |
1067 | if (IS_ERR(ufs->workdir)) { | |
cc6f67bc MS |
1068 | pr_warn("overlayfs: failed to create directory %s/%s (errno: %i); mounting read-only\n", |
1069 | ufs->config.workdir, OVL_WORKDIR_NAME, -err); | |
1070 | sb->s_flags |= MS_RDONLY; | |
1071 | ufs->workdir = NULL; | |
53a08cb9 | 1072 | } |
45aebeaf VG |
1073 | |
1074 | /* | |
1075 | * Upper should support d_type, else whiteouts are visible. | |
1076 | * Given workdir and upper are on same fs, we can do | |
21765194 VG |
1077 | * iterate_dir() on workdir. This check requires successful |
1078 | * creation of workdir in previous step. | |
45aebeaf | 1079 | */ |
21765194 VG |
1080 | if (ufs->workdir) { |
1081 | err = ovl_check_d_type_supported(&workpath); | |
1082 | if (err < 0) | |
1083 | goto out_put_workdir; | |
45aebeaf | 1084 | |
21765194 VG |
1085 | if (!err) { |
1086 | pr_err("overlayfs: upper fs needs to support d_type.\n"); | |
1087 | err = -EINVAL; | |
1088 | goto out_put_workdir; | |
1089 | } | |
45aebeaf | 1090 | } |
e9be9d5e MS |
1091 | } |
1092 | ||
2f83fd8c | 1093 | err = -ENOMEM; |
a78d9f0d | 1094 | ufs->lower_mnt = kcalloc(numlower, sizeof(struct vfsmount *), GFP_KERNEL); |
dd662667 | 1095 | if (ufs->lower_mnt == NULL) |
3b7a9a24 | 1096 | goto out_put_workdir; |
a78d9f0d MS |
1097 | for (i = 0; i < numlower; i++) { |
1098 | struct vfsmount *mnt = clone_private_mount(&stack[i]); | |
dd662667 | 1099 | |
2f83fd8c | 1100 | err = PTR_ERR(mnt); |
a78d9f0d MS |
1101 | if (IS_ERR(mnt)) { |
1102 | pr_err("overlayfs: failed to clone lowerpath\n"); | |
1103 | goto out_put_lower_mnt; | |
1104 | } | |
1105 | /* | |
1106 | * Make lower_mnt R/O. That way fchmod/fchown on lower file | |
1107 | * will fail instead of modifying lower fs. | |
1108 | */ | |
1109 | mnt->mnt_flags |= MNT_READONLY; | |
dd662667 | 1110 | |
a78d9f0d MS |
1111 | ufs->lower_mnt[ufs->numlower] = mnt; |
1112 | ufs->numlower++; | |
1113 | } | |
e9be9d5e | 1114 | |
71cbad7e | 1115 | /* If the upper fs is nonexistent, we mark overlayfs r/o too */ |
1116 | if (!ufs->upper_mnt) | |
e9be9d5e MS |
1117 | sb->s_flags |= MS_RDONLY; |
1118 | ||
7c03b5d4 MS |
1119 | if (remote) |
1120 | sb->s_d_op = &ovl_reval_dentry_operations; | |
1121 | else | |
1122 | sb->s_d_op = &ovl_dentry_operations; | |
e9be9d5e | 1123 | |
3fe6e52f AM |
1124 | ufs->creator_cred = prepare_creds(); |
1125 | if (!ufs->creator_cred) | |
1126 | goto out_put_lower_mnt; | |
1127 | ||
e9be9d5e | 1128 | err = -ENOMEM; |
a78d9f0d | 1129 | oe = ovl_alloc_entry(numlower); |
3b7a9a24 | 1130 | if (!oe) |
3fe6e52f | 1131 | goto out_put_cred; |
e9be9d5e | 1132 | |
3b7a9a24 | 1133 | root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, oe)); |
e9be9d5e | 1134 | if (!root_dentry) |
3b7a9a24 | 1135 | goto out_free_oe; |
e9be9d5e MS |
1136 | |
1137 | mntput(upperpath.mnt); | |
a78d9f0d MS |
1138 | for (i = 0; i < numlower; i++) |
1139 | mntput(stack[i].mnt); | |
e9be9d5e | 1140 | path_put(&workpath); |
a78d9f0d | 1141 | kfree(lowertmp); |
e9be9d5e MS |
1142 | |
1143 | oe->__upperdentry = upperpath.dentry; | |
a78d9f0d MS |
1144 | for (i = 0; i < numlower; i++) { |
1145 | oe->lowerstack[i].dentry = stack[i].dentry; | |
1146 | oe->lowerstack[i].mnt = ufs->lower_mnt[i]; | |
1147 | } | |
0f95502a | 1148 | kfree(stack); |
e9be9d5e MS |
1149 | |
1150 | root_dentry->d_fsdata = oe; | |
1151 | ||
ed06e069 MS |
1152 | ovl_copyattr(ovl_dentry_real(root_dentry)->d_inode, |
1153 | root_dentry->d_inode); | |
1154 | ||
cc259639 | 1155 | sb->s_magic = OVERLAYFS_SUPER_MAGIC; |
e9be9d5e MS |
1156 | sb->s_op = &ovl_super_operations; |
1157 | sb->s_root = root_dentry; | |
1158 | sb->s_fs_info = ufs; | |
1159 | ||
1160 | return 0; | |
1161 | ||
3b7a9a24 MS |
1162 | out_free_oe: |
1163 | kfree(oe); | |
3fe6e52f AM |
1164 | out_put_cred: |
1165 | put_cred(ufs->creator_cred); | |
e9be9d5e | 1166 | out_put_lower_mnt: |
dd662667 MS |
1167 | for (i = 0; i < ufs->numlower; i++) |
1168 | mntput(ufs->lower_mnt[i]); | |
1169 | kfree(ufs->lower_mnt); | |
3b7a9a24 MS |
1170 | out_put_workdir: |
1171 | dput(ufs->workdir); | |
e9be9d5e | 1172 | mntput(ufs->upper_mnt); |
e9be9d5e | 1173 | out_put_lowerpath: |
a78d9f0d MS |
1174 | for (i = 0; i < numlower; i++) |
1175 | path_put(&stack[i]); | |
1176 | kfree(stack); | |
1177 | out_free_lowertmp: | |
1178 | kfree(lowertmp); | |
3b7a9a24 MS |
1179 | out_put_workpath: |
1180 | path_put(&workpath); | |
e9be9d5e MS |
1181 | out_put_upperpath: |
1182 | path_put(&upperpath); | |
e9be9d5e | 1183 | out_free_config: |
f45827e8 EZ |
1184 | kfree(ufs->config.lowerdir); |
1185 | kfree(ufs->config.upperdir); | |
1186 | kfree(ufs->config.workdir); | |
1187 | kfree(ufs); | |
e9be9d5e MS |
1188 | out: |
1189 | return err; | |
1190 | } | |
1191 | ||
1192 | static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, | |
1193 | const char *dev_name, void *raw_data) | |
1194 | { | |
1195 | return mount_nodev(fs_type, flags, raw_data, ovl_fill_super); | |
1196 | } | |
1197 | ||
1198 | static struct file_system_type ovl_fs_type = { | |
1199 | .owner = THIS_MODULE, | |
ef94b186 | 1200 | .name = "overlay", |
e9be9d5e MS |
1201 | .mount = ovl_mount, |
1202 | .kill_sb = kill_anon_super, | |
1203 | }; | |
ef94b186 | 1204 | MODULE_ALIAS_FS("overlay"); |
e9be9d5e MS |
1205 | |
1206 | static int __init ovl_init(void) | |
1207 | { | |
1208 | return register_filesystem(&ovl_fs_type); | |
1209 | } | |
1210 | ||
1211 | static void __exit ovl_exit(void) | |
1212 | { | |
1213 | unregister_filesystem(&ovl_fs_type); | |
1214 | } | |
1215 | ||
1216 | module_init(ovl_init); | |
1217 | module_exit(ovl_exit); |