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> | |
12 | #include <linux/xattr.h> | |
13 | #include <linux/security.h> | |
14 | #include <linux/cred.h> | |
15 | #include "overlayfs.h" | |
16 | ||
17 | void ovl_cleanup(struct inode *wdir, struct dentry *wdentry) | |
18 | { | |
19 | int err; | |
20 | ||
21 | dget(wdentry); | |
e36cb0b8 | 22 | if (d_is_dir(wdentry)) |
e9be9d5e MS |
23 | err = ovl_do_rmdir(wdir, wdentry); |
24 | else | |
25 | err = ovl_do_unlink(wdir, wdentry); | |
26 | dput(wdentry); | |
27 | ||
28 | if (err) { | |
29 | pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n", | |
30 | wdentry, err); | |
31 | } | |
32 | } | |
33 | ||
34 | struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry) | |
35 | { | |
36 | struct dentry *temp; | |
37 | char name[20]; | |
38 | ||
39 | snprintf(name, sizeof(name), "#%lx", (unsigned long) dentry); | |
40 | ||
41 | temp = lookup_one_len(name, workdir, strlen(name)); | |
42 | if (!IS_ERR(temp) && temp->d_inode) { | |
43 | pr_err("overlayfs: workdir/%s already exists\n", name); | |
44 | dput(temp); | |
45 | temp = ERR_PTR(-EIO); | |
46 | } | |
47 | ||
48 | return temp; | |
49 | } | |
50 | ||
51 | /* caller holds i_mutex on workdir */ | |
52 | static struct dentry *ovl_whiteout(struct dentry *workdir, | |
53 | struct dentry *dentry) | |
54 | { | |
55 | int err; | |
56 | struct dentry *whiteout; | |
57 | struct inode *wdir = workdir->d_inode; | |
58 | ||
59 | whiteout = ovl_lookup_temp(workdir, dentry); | |
60 | if (IS_ERR(whiteout)) | |
61 | return whiteout; | |
62 | ||
63 | err = ovl_do_whiteout(wdir, whiteout); | |
64 | if (err) { | |
65 | dput(whiteout); | |
66 | whiteout = ERR_PTR(err); | |
67 | } | |
68 | ||
69 | return whiteout; | |
70 | } | |
71 | ||
72 | int ovl_create_real(struct inode *dir, struct dentry *newdentry, | |
73 | struct kstat *stat, const char *link, | |
74 | struct dentry *hardlink, bool debug) | |
75 | { | |
76 | int err; | |
77 | ||
78 | if (newdentry->d_inode) | |
79 | return -ESTALE; | |
80 | ||
81 | if (hardlink) { | |
82 | err = ovl_do_link(hardlink, dir, newdentry, debug); | |
83 | } else { | |
84 | switch (stat->mode & S_IFMT) { | |
85 | case S_IFREG: | |
86 | err = ovl_do_create(dir, newdentry, stat->mode, debug); | |
87 | break; | |
88 | ||
89 | case S_IFDIR: | |
90 | err = ovl_do_mkdir(dir, newdentry, stat->mode, debug); | |
91 | break; | |
92 | ||
93 | case S_IFCHR: | |
94 | case S_IFBLK: | |
95 | case S_IFIFO: | |
96 | case S_IFSOCK: | |
97 | err = ovl_do_mknod(dir, newdentry, | |
98 | stat->mode, stat->rdev, debug); | |
99 | break; | |
100 | ||
101 | case S_IFLNK: | |
102 | err = ovl_do_symlink(dir, newdentry, link, debug); | |
103 | break; | |
104 | ||
105 | default: | |
106 | err = -EPERM; | |
107 | } | |
108 | } | |
109 | if (!err && WARN_ON(!newdentry->d_inode)) { | |
110 | /* | |
111 | * Not quite sure if non-instantiated dentry is legal or not. | |
112 | * VFS doesn't seem to care so check and warn here. | |
113 | */ | |
114 | err = -ENOENT; | |
115 | } | |
116 | return err; | |
117 | } | |
118 | ||
119 | static int ovl_set_opaque(struct dentry *upperdentry) | |
120 | { | |
cead89bb | 121 | return ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0); |
e9be9d5e MS |
122 | } |
123 | ||
124 | static void ovl_remove_opaque(struct dentry *upperdentry) | |
125 | { | |
126 | int err; | |
127 | ||
cead89bb | 128 | err = ovl_do_removexattr(upperdentry, OVL_XATTR_OPAQUE); |
e9be9d5e MS |
129 | if (err) { |
130 | pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n", | |
131 | upperdentry->d_name.name, err); | |
132 | } | |
133 | } | |
134 | ||
135 | static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry, | |
136 | struct kstat *stat) | |
137 | { | |
138 | int err; | |
139 | enum ovl_path_type type; | |
140 | struct path realpath; | |
141 | ||
142 | type = ovl_path_real(dentry, &realpath); | |
143 | err = vfs_getattr(&realpath, stat); | |
144 | if (err) | |
145 | return err; | |
146 | ||
147 | stat->dev = dentry->d_sb->s_dev; | |
148 | stat->ino = dentry->d_inode->i_ino; | |
149 | ||
150 | /* | |
151 | * It's probably not worth it to count subdirs to get the | |
152 | * correct link count. nlink=1 seems to pacify 'find' and | |
153 | * other utilities. | |
154 | */ | |
1afaba1e | 155 | if (OVL_TYPE_MERGE(type)) |
e9be9d5e MS |
156 | stat->nlink = 1; |
157 | ||
158 | return 0; | |
159 | } | |
160 | ||
161 | static int ovl_create_upper(struct dentry *dentry, struct inode *inode, | |
162 | struct kstat *stat, const char *link, | |
163 | struct dentry *hardlink) | |
164 | { | |
165 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
166 | struct inode *udir = upperdir->d_inode; | |
167 | struct dentry *newdentry; | |
168 | int err; | |
169 | ||
5955102c | 170 | inode_lock_nested(udir, I_MUTEX_PARENT); |
e9be9d5e MS |
171 | newdentry = lookup_one_len(dentry->d_name.name, upperdir, |
172 | dentry->d_name.len); | |
173 | err = PTR_ERR(newdentry); | |
174 | if (IS_ERR(newdentry)) | |
175 | goto out_unlock; | |
176 | err = ovl_create_real(udir, newdentry, stat, link, hardlink, false); | |
177 | if (err) | |
178 | goto out_dput; | |
179 | ||
180 | ovl_dentry_version_inc(dentry->d_parent); | |
181 | ovl_dentry_update(dentry, newdentry); | |
182 | ovl_copyattr(newdentry->d_inode, inode); | |
183 | d_instantiate(dentry, inode); | |
184 | newdentry = NULL; | |
185 | out_dput: | |
186 | dput(newdentry); | |
187 | out_unlock: | |
5955102c | 188 | inode_unlock(udir); |
e9be9d5e MS |
189 | return err; |
190 | } | |
191 | ||
192 | static int ovl_lock_rename_workdir(struct dentry *workdir, | |
193 | struct dentry *upperdir) | |
194 | { | |
195 | /* Workdir should not be the same as upperdir */ | |
196 | if (workdir == upperdir) | |
197 | goto err; | |
198 | ||
199 | /* Workdir should not be subdir of upperdir and vice versa */ | |
200 | if (lock_rename(workdir, upperdir) != NULL) | |
201 | goto err_unlock; | |
202 | ||
203 | return 0; | |
204 | ||
205 | err_unlock: | |
206 | unlock_rename(workdir, upperdir); | |
207 | err: | |
208 | pr_err("overlayfs: failed to lock workdir+upperdir\n"); | |
209 | return -EIO; | |
210 | } | |
211 | ||
212 | static struct dentry *ovl_clear_empty(struct dentry *dentry, | |
213 | struct list_head *list) | |
214 | { | |
215 | struct dentry *workdir = ovl_workdir(dentry); | |
216 | struct inode *wdir = workdir->d_inode; | |
217 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
218 | struct inode *udir = upperdir->d_inode; | |
219 | struct path upperpath; | |
220 | struct dentry *upper; | |
221 | struct dentry *opaquedir; | |
222 | struct kstat stat; | |
223 | int err; | |
224 | ||
cc6f67bc MS |
225 | if (WARN_ON(!workdir)) |
226 | return ERR_PTR(-EROFS); | |
227 | ||
e9be9d5e MS |
228 | err = ovl_lock_rename_workdir(workdir, upperdir); |
229 | if (err) | |
230 | goto out; | |
231 | ||
232 | ovl_path_upper(dentry, &upperpath); | |
233 | err = vfs_getattr(&upperpath, &stat); | |
234 | if (err) | |
235 | goto out_unlock; | |
236 | ||
237 | err = -ESTALE; | |
238 | if (!S_ISDIR(stat.mode)) | |
239 | goto out_unlock; | |
240 | upper = upperpath.dentry; | |
241 | if (upper->d_parent->d_inode != udir) | |
242 | goto out_unlock; | |
243 | ||
244 | opaquedir = ovl_lookup_temp(workdir, dentry); | |
245 | err = PTR_ERR(opaquedir); | |
246 | if (IS_ERR(opaquedir)) | |
247 | goto out_unlock; | |
248 | ||
249 | err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true); | |
250 | if (err) | |
251 | goto out_dput; | |
252 | ||
253 | err = ovl_copy_xattr(upper, opaquedir); | |
254 | if (err) | |
255 | goto out_cleanup; | |
256 | ||
257 | err = ovl_set_opaque(opaquedir); | |
258 | if (err) | |
259 | goto out_cleanup; | |
260 | ||
5955102c | 261 | inode_lock(opaquedir->d_inode); |
e9be9d5e | 262 | err = ovl_set_attr(opaquedir, &stat); |
5955102c | 263 | inode_unlock(opaquedir->d_inode); |
e9be9d5e MS |
264 | if (err) |
265 | goto out_cleanup; | |
266 | ||
267 | err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE); | |
268 | if (err) | |
269 | goto out_cleanup; | |
270 | ||
271 | ovl_cleanup_whiteouts(upper, list); | |
272 | ovl_cleanup(wdir, upper); | |
273 | unlock_rename(workdir, upperdir); | |
274 | ||
275 | /* dentry's upper doesn't match now, get rid of it */ | |
276 | d_drop(dentry); | |
277 | ||
278 | return opaquedir; | |
279 | ||
280 | out_cleanup: | |
281 | ovl_cleanup(wdir, opaquedir); | |
282 | out_dput: | |
283 | dput(opaquedir); | |
284 | out_unlock: | |
285 | unlock_rename(workdir, upperdir); | |
286 | out: | |
287 | return ERR_PTR(err); | |
288 | } | |
289 | ||
a105d685 | 290 | static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry) |
e9be9d5e MS |
291 | { |
292 | int err; | |
293 | struct dentry *ret = NULL; | |
294 | LIST_HEAD(list); | |
295 | ||
296 | err = ovl_check_empty_dir(dentry, &list); | |
297 | if (err) | |
298 | ret = ERR_PTR(err); | |
a105d685 MS |
299 | else { |
300 | /* | |
301 | * If no upperdentry then skip clearing whiteouts. | |
302 | * | |
303 | * Can race with copy-up, since we don't hold the upperdir | |
304 | * mutex. Doesn't matter, since copy-up can't create a | |
305 | * non-empty directory from an empty one. | |
306 | */ | |
307 | if (ovl_dentry_upper(dentry)) | |
308 | ret = ovl_clear_empty(dentry, &list); | |
309 | } | |
e9be9d5e MS |
310 | |
311 | ovl_cache_free(&list); | |
312 | ||
313 | return ret; | |
314 | } | |
315 | ||
316 | static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, | |
317 | struct kstat *stat, const char *link, | |
318 | struct dentry *hardlink) | |
319 | { | |
320 | struct dentry *workdir = ovl_workdir(dentry); | |
321 | struct inode *wdir = workdir->d_inode; | |
322 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
323 | struct inode *udir = upperdir->d_inode; | |
324 | struct dentry *upper; | |
325 | struct dentry *newdentry; | |
326 | int err; | |
327 | ||
cc6f67bc MS |
328 | if (WARN_ON(!workdir)) |
329 | return -EROFS; | |
330 | ||
e9be9d5e MS |
331 | err = ovl_lock_rename_workdir(workdir, upperdir); |
332 | if (err) | |
333 | goto out; | |
334 | ||
335 | newdentry = ovl_lookup_temp(workdir, dentry); | |
336 | err = PTR_ERR(newdentry); | |
337 | if (IS_ERR(newdentry)) | |
338 | goto out_unlock; | |
339 | ||
340 | upper = lookup_one_len(dentry->d_name.name, upperdir, | |
341 | dentry->d_name.len); | |
342 | err = PTR_ERR(upper); | |
343 | if (IS_ERR(upper)) | |
344 | goto out_dput; | |
345 | ||
346 | err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true); | |
347 | if (err) | |
348 | goto out_dput2; | |
349 | ||
350 | if (S_ISDIR(stat->mode)) { | |
351 | err = ovl_set_opaque(newdentry); | |
352 | if (err) | |
353 | goto out_cleanup; | |
354 | ||
355 | err = ovl_do_rename(wdir, newdentry, udir, upper, | |
356 | RENAME_EXCHANGE); | |
357 | if (err) | |
358 | goto out_cleanup; | |
359 | ||
360 | ovl_cleanup(wdir, upper); | |
361 | } else { | |
362 | err = ovl_do_rename(wdir, newdentry, udir, upper, 0); | |
363 | if (err) | |
364 | goto out_cleanup; | |
365 | } | |
366 | ovl_dentry_version_inc(dentry->d_parent); | |
367 | ovl_dentry_update(dentry, newdentry); | |
368 | ovl_copyattr(newdentry->d_inode, inode); | |
369 | d_instantiate(dentry, inode); | |
370 | newdentry = NULL; | |
371 | out_dput2: | |
372 | dput(upper); | |
373 | out_dput: | |
374 | dput(newdentry); | |
375 | out_unlock: | |
376 | unlock_rename(workdir, upperdir); | |
377 | out: | |
378 | return err; | |
379 | ||
380 | out_cleanup: | |
381 | ovl_cleanup(wdir, newdentry); | |
382 | goto out_dput2; | |
383 | } | |
384 | ||
385 | static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev, | |
386 | const char *link, struct dentry *hardlink) | |
387 | { | |
388 | int err; | |
389 | struct inode *inode; | |
390 | struct kstat stat = { | |
391 | .mode = mode, | |
392 | .rdev = rdev, | |
393 | }; | |
394 | ||
395 | err = -ENOMEM; | |
396 | inode = ovl_new_inode(dentry->d_sb, mode, dentry->d_fsdata); | |
397 | if (!inode) | |
398 | goto out; | |
399 | ||
400 | err = ovl_copy_up(dentry->d_parent); | |
401 | if (err) | |
402 | goto out_iput; | |
403 | ||
404 | if (!ovl_dentry_is_opaque(dentry)) { | |
405 | err = ovl_create_upper(dentry, inode, &stat, link, hardlink); | |
406 | } else { | |
407 | const struct cred *old_cred; | |
e9be9d5e | 408 | |
3fe6e52f | 409 | old_cred = ovl_override_creds(dentry->d_sb); |
e9be9d5e MS |
410 | |
411 | err = ovl_create_over_whiteout(dentry, inode, &stat, link, | |
412 | hardlink); | |
413 | ||
414 | revert_creds(old_cred); | |
e9be9d5e MS |
415 | } |
416 | ||
417 | if (!err) | |
418 | inode = NULL; | |
419 | out_iput: | |
420 | iput(inode); | |
421 | out: | |
422 | return err; | |
423 | } | |
424 | ||
425 | static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, | |
426 | const char *link) | |
427 | { | |
428 | int err; | |
429 | ||
430 | err = ovl_want_write(dentry); | |
431 | if (!err) { | |
432 | err = ovl_create_or_link(dentry, mode, rdev, link, NULL); | |
433 | ovl_drop_write(dentry); | |
434 | } | |
435 | ||
436 | return err; | |
437 | } | |
438 | ||
439 | static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode, | |
440 | bool excl) | |
441 | { | |
442 | return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL); | |
443 | } | |
444 | ||
445 | static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) | |
446 | { | |
447 | return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL); | |
448 | } | |
449 | ||
450 | static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, | |
451 | dev_t rdev) | |
452 | { | |
453 | /* Don't allow creation of "whiteout" on overlay */ | |
454 | if (S_ISCHR(mode) && rdev == WHITEOUT_DEV) | |
455 | return -EPERM; | |
456 | ||
457 | return ovl_create_object(dentry, mode, rdev, NULL); | |
458 | } | |
459 | ||
460 | static int ovl_symlink(struct inode *dir, struct dentry *dentry, | |
461 | const char *link) | |
462 | { | |
463 | return ovl_create_object(dentry, S_IFLNK, 0, link); | |
464 | } | |
465 | ||
466 | static int ovl_link(struct dentry *old, struct inode *newdir, | |
467 | struct dentry *new) | |
468 | { | |
469 | int err; | |
470 | struct dentry *upper; | |
471 | ||
472 | err = ovl_want_write(old); | |
473 | if (err) | |
474 | goto out; | |
475 | ||
476 | err = ovl_copy_up(old); | |
477 | if (err) | |
478 | goto out_drop_write; | |
479 | ||
480 | upper = ovl_dentry_upper(old); | |
481 | err = ovl_create_or_link(new, upper->d_inode->i_mode, 0, NULL, upper); | |
482 | ||
483 | out_drop_write: | |
484 | ovl_drop_write(old); | |
485 | out: | |
486 | return err; | |
487 | } | |
488 | ||
a105d685 | 489 | static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir) |
e9be9d5e MS |
490 | { |
491 | struct dentry *workdir = ovl_workdir(dentry); | |
492 | struct inode *wdir = workdir->d_inode; | |
493 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
494 | struct inode *udir = upperdir->d_inode; | |
495 | struct dentry *whiteout; | |
496 | struct dentry *upper; | |
497 | struct dentry *opaquedir = NULL; | |
498 | int err; | |
499 | ||
cc6f67bc MS |
500 | if (WARN_ON(!workdir)) |
501 | return -EROFS; | |
502 | ||
d377c5eb MS |
503 | if (is_dir) { |
504 | if (OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) { | |
505 | opaquedir = ovl_check_empty_and_clear(dentry); | |
506 | err = PTR_ERR(opaquedir); | |
507 | if (IS_ERR(opaquedir)) | |
508 | goto out; | |
509 | } else { | |
510 | LIST_HEAD(list); | |
511 | ||
512 | /* | |
513 | * When removing an empty opaque directory, then it | |
514 | * makes no sense to replace it with an exact replica of | |
515 | * itself. But emptiness still needs to be checked. | |
516 | */ | |
517 | err = ovl_check_empty_dir(dentry, &list); | |
518 | ovl_cache_free(&list); | |
519 | if (err) | |
520 | goto out; | |
521 | } | |
e9be9d5e MS |
522 | } |
523 | ||
524 | err = ovl_lock_rename_workdir(workdir, upperdir); | |
525 | if (err) | |
526 | goto out_dput; | |
527 | ||
528 | whiteout = ovl_whiteout(workdir, dentry); | |
529 | err = PTR_ERR(whiteout); | |
530 | if (IS_ERR(whiteout)) | |
531 | goto out_unlock; | |
532 | ||
a105d685 MS |
533 | upper = ovl_dentry_upper(dentry); |
534 | if (!upper) { | |
e9be9d5e | 535 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
a105d685 | 536 | dentry->d_name.len); |
e9be9d5e MS |
537 | err = PTR_ERR(upper); |
538 | if (IS_ERR(upper)) | |
539 | goto kill_whiteout; | |
540 | ||
541 | err = ovl_do_rename(wdir, whiteout, udir, upper, 0); | |
542 | dput(upper); | |
543 | if (err) | |
544 | goto kill_whiteout; | |
545 | } else { | |
546 | int flags = 0; | |
547 | ||
e9be9d5e MS |
548 | if (opaquedir) |
549 | upper = opaquedir; | |
550 | err = -ESTALE; | |
551 | if (upper->d_parent != upperdir) | |
552 | goto kill_whiteout; | |
553 | ||
554 | if (is_dir) | |
555 | flags |= RENAME_EXCHANGE; | |
556 | ||
557 | err = ovl_do_rename(wdir, whiteout, udir, upper, flags); | |
558 | if (err) | |
559 | goto kill_whiteout; | |
560 | ||
561 | if (is_dir) | |
562 | ovl_cleanup(wdir, upper); | |
563 | } | |
564 | ovl_dentry_version_inc(dentry->d_parent); | |
565 | out_d_drop: | |
566 | d_drop(dentry); | |
567 | dput(whiteout); | |
568 | out_unlock: | |
569 | unlock_rename(workdir, upperdir); | |
570 | out_dput: | |
571 | dput(opaquedir); | |
572 | out: | |
573 | return err; | |
574 | ||
575 | kill_whiteout: | |
576 | ovl_cleanup(wdir, whiteout); | |
577 | goto out_d_drop; | |
578 | } | |
579 | ||
580 | static int ovl_remove_upper(struct dentry *dentry, bool is_dir) | |
581 | { | |
582 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
583 | struct inode *dir = upperdir->d_inode; | |
11f37104 | 584 | struct dentry *upper; |
e9be9d5e MS |
585 | int err; |
586 | ||
5955102c | 587 | inode_lock_nested(dir, I_MUTEX_PARENT); |
11f37104 MS |
588 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
589 | dentry->d_name.len); | |
590 | err = PTR_ERR(upper); | |
591 | if (IS_ERR(upper)) | |
592 | goto out_unlock; | |
593 | ||
e9be9d5e | 594 | err = -ESTALE; |
11f37104 | 595 | if (upper == ovl_dentry_upper(dentry)) { |
e9be9d5e MS |
596 | if (is_dir) |
597 | err = vfs_rmdir(dir, upper); | |
598 | else | |
599 | err = vfs_unlink(dir, upper, NULL); | |
e9be9d5e MS |
600 | ovl_dentry_version_inc(dentry->d_parent); |
601 | } | |
11f37104 | 602 | dput(upper); |
e9be9d5e MS |
603 | |
604 | /* | |
605 | * Keeping this dentry hashed would mean having to release | |
606 | * upperpath/lowerpath, which could only be done if we are the | |
607 | * sole user of this dentry. Too tricky... Just unhash for | |
608 | * now. | |
609 | */ | |
ce9113bb RW |
610 | if (!err) |
611 | d_drop(dentry); | |
11f37104 | 612 | out_unlock: |
5955102c | 613 | inode_unlock(dir); |
e9be9d5e MS |
614 | |
615 | return err; | |
616 | } | |
617 | ||
618 | static inline int ovl_check_sticky(struct dentry *dentry) | |
619 | { | |
620 | struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode; | |
621 | struct inode *inode = ovl_dentry_real(dentry)->d_inode; | |
622 | ||
623 | if (check_sticky(dir, inode)) | |
624 | return -EPERM; | |
625 | ||
626 | return 0; | |
627 | } | |
628 | ||
629 | static int ovl_do_remove(struct dentry *dentry, bool is_dir) | |
630 | { | |
631 | enum ovl_path_type type; | |
632 | int err; | |
633 | ||
634 | err = ovl_check_sticky(dentry); | |
635 | if (err) | |
636 | goto out; | |
637 | ||
638 | err = ovl_want_write(dentry); | |
639 | if (err) | |
640 | goto out; | |
641 | ||
642 | err = ovl_copy_up(dentry->d_parent); | |
643 | if (err) | |
644 | goto out_drop_write; | |
645 | ||
646 | type = ovl_path_type(dentry); | |
1afaba1e | 647 | if (OVL_TYPE_PURE_UPPER(type)) { |
e9be9d5e MS |
648 | err = ovl_remove_upper(dentry, is_dir); |
649 | } else { | |
3fe6e52f | 650 | const struct cred *old_cred = ovl_override_creds(dentry->d_sb); |
e9be9d5e | 651 | |
a105d685 | 652 | err = ovl_remove_and_whiteout(dentry, is_dir); |
e9be9d5e MS |
653 | |
654 | revert_creds(old_cred); | |
e9be9d5e MS |
655 | } |
656 | out_drop_write: | |
657 | ovl_drop_write(dentry); | |
658 | out: | |
659 | return err; | |
660 | } | |
661 | ||
662 | static int ovl_unlink(struct inode *dir, struct dentry *dentry) | |
663 | { | |
664 | return ovl_do_remove(dentry, false); | |
665 | } | |
666 | ||
667 | static int ovl_rmdir(struct inode *dir, struct dentry *dentry) | |
668 | { | |
669 | return ovl_do_remove(dentry, true); | |
670 | } | |
671 | ||
672 | static int ovl_rename2(struct inode *olddir, struct dentry *old, | |
673 | struct inode *newdir, struct dentry *new, | |
674 | unsigned int flags) | |
675 | { | |
676 | int err; | |
677 | enum ovl_path_type old_type; | |
678 | enum ovl_path_type new_type; | |
679 | struct dentry *old_upperdir; | |
680 | struct dentry *new_upperdir; | |
681 | struct dentry *olddentry; | |
682 | struct dentry *newdentry; | |
683 | struct dentry *trap; | |
684 | bool old_opaque; | |
685 | bool new_opaque; | |
e9be9d5e MS |
686 | bool cleanup_whiteout = false; |
687 | bool overwrite = !(flags & RENAME_EXCHANGE); | |
e36cb0b8 | 688 | bool is_dir = d_is_dir(old); |
e9be9d5e MS |
689 | bool new_is_dir = false; |
690 | struct dentry *opaquedir = NULL; | |
691 | const struct cred *old_cred = NULL; | |
e9be9d5e MS |
692 | |
693 | err = -EINVAL; | |
694 | if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) | |
695 | goto out; | |
696 | ||
697 | flags &= ~RENAME_NOREPLACE; | |
698 | ||
699 | err = ovl_check_sticky(old); | |
700 | if (err) | |
701 | goto out; | |
702 | ||
703 | /* Don't copy up directory trees */ | |
704 | old_type = ovl_path_type(old); | |
705 | err = -EXDEV; | |
1afaba1e | 706 | if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir) |
e9be9d5e MS |
707 | goto out; |
708 | ||
709 | if (new->d_inode) { | |
710 | err = ovl_check_sticky(new); | |
711 | if (err) | |
712 | goto out; | |
713 | ||
e36cb0b8 | 714 | if (d_is_dir(new)) |
e9be9d5e MS |
715 | new_is_dir = true; |
716 | ||
717 | new_type = ovl_path_type(new); | |
718 | err = -EXDEV; | |
1afaba1e | 719 | if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) |
e9be9d5e MS |
720 | goto out; |
721 | ||
722 | err = 0; | |
1afaba1e | 723 | if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) { |
e9be9d5e MS |
724 | if (ovl_dentry_lower(old)->d_inode == |
725 | ovl_dentry_lower(new)->d_inode) | |
726 | goto out; | |
727 | } | |
1afaba1e | 728 | if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) { |
e9be9d5e MS |
729 | if (ovl_dentry_upper(old)->d_inode == |
730 | ovl_dentry_upper(new)->d_inode) | |
731 | goto out; | |
732 | } | |
733 | } else { | |
734 | if (ovl_dentry_is_opaque(new)) | |
1afaba1e | 735 | new_type = __OVL_PATH_UPPER; |
e9be9d5e | 736 | else |
1afaba1e | 737 | new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE; |
e9be9d5e MS |
738 | } |
739 | ||
740 | err = ovl_want_write(old); | |
741 | if (err) | |
742 | goto out; | |
743 | ||
744 | err = ovl_copy_up(old); | |
745 | if (err) | |
746 | goto out_drop_write; | |
747 | ||
748 | err = ovl_copy_up(new->d_parent); | |
749 | if (err) | |
750 | goto out_drop_write; | |
751 | if (!overwrite) { | |
752 | err = ovl_copy_up(new); | |
753 | if (err) | |
754 | goto out_drop_write; | |
755 | } | |
756 | ||
1afaba1e MS |
757 | old_opaque = !OVL_TYPE_PURE_UPPER(old_type); |
758 | new_opaque = !OVL_TYPE_PURE_UPPER(new_type); | |
e9be9d5e | 759 | |
3fe6e52f AM |
760 | if (old_opaque || new_opaque) |
761 | old_cred = ovl_override_creds(old->d_sb); | |
e9be9d5e | 762 | |
1afaba1e | 763 | if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) { |
a105d685 | 764 | opaquedir = ovl_check_empty_and_clear(new); |
e9be9d5e MS |
765 | err = PTR_ERR(opaquedir); |
766 | if (IS_ERR(opaquedir)) { | |
767 | opaquedir = NULL; | |
768 | goto out_revert_creds; | |
769 | } | |
770 | } | |
771 | ||
772 | if (overwrite) { | |
773 | if (old_opaque) { | |
774 | if (new->d_inode || !new_opaque) { | |
775 | /* Whiteout source */ | |
776 | flags |= RENAME_WHITEOUT; | |
777 | } else { | |
778 | /* Switch whiteouts */ | |
779 | flags |= RENAME_EXCHANGE; | |
780 | } | |
781 | } else if (is_dir && !new->d_inode && new_opaque) { | |
782 | flags |= RENAME_EXCHANGE; | |
783 | cleanup_whiteout = true; | |
784 | } | |
785 | } | |
786 | ||
787 | old_upperdir = ovl_dentry_upper(old->d_parent); | |
788 | new_upperdir = ovl_dentry_upper(new->d_parent); | |
789 | ||
790 | trap = lock_rename(new_upperdir, old_upperdir); | |
791 | ||
11f37104 MS |
792 | |
793 | olddentry = lookup_one_len(old->d_name.name, old_upperdir, | |
794 | old->d_name.len); | |
795 | err = PTR_ERR(olddentry); | |
796 | if (IS_ERR(olddentry)) | |
797 | goto out_unlock; | |
798 | ||
799 | err = -ESTALE; | |
800 | if (olddentry != ovl_dentry_upper(old)) | |
801 | goto out_dput_old; | |
802 | ||
803 | newdentry = lookup_one_len(new->d_name.name, new_upperdir, | |
804 | new->d_name.len); | |
805 | err = PTR_ERR(newdentry); | |
806 | if (IS_ERR(newdentry)) | |
807 | goto out_dput_old; | |
808 | ||
809 | err = -ESTALE; | |
810 | if (ovl_dentry_upper(new)) { | |
e9be9d5e | 811 | if (opaquedir) { |
11f37104 MS |
812 | if (newdentry != opaquedir) |
813 | goto out_dput; | |
e9be9d5e | 814 | } else { |
11f37104 MS |
815 | if (newdentry != ovl_dentry_upper(new)) |
816 | goto out_dput; | |
e9be9d5e MS |
817 | } |
818 | } else { | |
11f37104 MS |
819 | if (!d_is_negative(newdentry) && |
820 | (!new_opaque || !ovl_is_whiteout(newdentry))) | |
821 | goto out_dput; | |
e9be9d5e MS |
822 | } |
823 | ||
e9be9d5e MS |
824 | if (olddentry == trap) |
825 | goto out_dput; | |
826 | if (newdentry == trap) | |
827 | goto out_dput; | |
828 | ||
829 | if (is_dir && !old_opaque && new_opaque) { | |
830 | err = ovl_set_opaque(olddentry); | |
831 | if (err) | |
832 | goto out_dput; | |
833 | } | |
834 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) { | |
835 | err = ovl_set_opaque(newdentry); | |
836 | if (err) | |
837 | goto out_dput; | |
838 | } | |
839 | ||
840 | if (old_opaque || new_opaque) { | |
841 | err = ovl_do_rename(old_upperdir->d_inode, olddentry, | |
842 | new_upperdir->d_inode, newdentry, | |
843 | flags); | |
844 | } else { | |
845 | /* No debug for the plain case */ | |
846 | BUG_ON(flags & ~RENAME_EXCHANGE); | |
847 | err = vfs_rename(old_upperdir->d_inode, olddentry, | |
848 | new_upperdir->d_inode, newdentry, | |
849 | NULL, flags); | |
850 | } | |
851 | ||
852 | if (err) { | |
853 | if (is_dir && !old_opaque && new_opaque) | |
854 | ovl_remove_opaque(olddentry); | |
855 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) | |
856 | ovl_remove_opaque(newdentry); | |
857 | goto out_dput; | |
858 | } | |
859 | ||
860 | if (is_dir && old_opaque && !new_opaque) | |
861 | ovl_remove_opaque(olddentry); | |
862 | if (!overwrite && new_is_dir && !old_opaque && new_opaque) | |
863 | ovl_remove_opaque(newdentry); | |
864 | ||
45d11738 KK |
865 | /* |
866 | * Old dentry now lives in different location. Dentries in | |
867 | * lowerstack are stale. We cannot drop them here because | |
868 | * access to them is lockless. This could be only pure upper | |
869 | * or opaque directory - numlower is zero. Or upper non-dir | |
870 | * entry - its pureness is tracked by flag opaque. | |
871 | */ | |
e9be9d5e MS |
872 | if (old_opaque != new_opaque) { |
873 | ovl_dentry_set_opaque(old, new_opaque); | |
874 | if (!overwrite) | |
875 | ovl_dentry_set_opaque(new, old_opaque); | |
876 | } | |
877 | ||
878 | if (cleanup_whiteout) | |
879 | ovl_cleanup(old_upperdir->d_inode, newdentry); | |
880 | ||
881 | ovl_dentry_version_inc(old->d_parent); | |
882 | ovl_dentry_version_inc(new->d_parent); | |
883 | ||
884 | out_dput: | |
885 | dput(newdentry); | |
11f37104 MS |
886 | out_dput_old: |
887 | dput(olddentry); | |
e9be9d5e MS |
888 | out_unlock: |
889 | unlock_rename(new_upperdir, old_upperdir); | |
890 | out_revert_creds: | |
3fe6e52f | 891 | if (old_opaque || new_opaque) |
e9be9d5e | 892 | revert_creds(old_cred); |
e9be9d5e MS |
893 | out_drop_write: |
894 | ovl_drop_write(old); | |
895 | out: | |
896 | dput(opaquedir); | |
897 | return err; | |
898 | } | |
899 | ||
900 | const struct inode_operations ovl_dir_inode_operations = { | |
901 | .lookup = ovl_lookup, | |
902 | .mkdir = ovl_mkdir, | |
903 | .symlink = ovl_symlink, | |
904 | .unlink = ovl_unlink, | |
905 | .rmdir = ovl_rmdir, | |
906 | .rename2 = ovl_rename2, | |
907 | .link = ovl_link, | |
908 | .setattr = ovl_setattr, | |
909 | .create = ovl_create, | |
910 | .mknod = ovl_mknod, | |
911 | .permission = ovl_permission, | |
912 | .getattr = ovl_dir_getattr, | |
913 | .setxattr = ovl_setxattr, | |
914 | .getxattr = ovl_getxattr, | |
915 | .listxattr = ovl_listxattr, | |
916 | .removexattr = ovl_removexattr, | |
917 | }; |