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 | ||
170 | mutex_lock_nested(&udir->i_mutex, I_MUTEX_PARENT); | |
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: | |
188 | mutex_unlock(&udir->i_mutex); | |
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 | ||
261 | mutex_lock(&opaquedir->d_inode->i_mutex); | |
262 | err = ovl_set_attr(opaquedir, &stat); | |
263 | mutex_unlock(&opaquedir->d_inode->i_mutex); | |
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; | |
408 | struct cred *override_cred; | |
409 | ||
410 | err = -ENOMEM; | |
411 | override_cred = prepare_creds(); | |
412 | if (!override_cred) | |
413 | goto out_iput; | |
414 | ||
415 | /* | |
416 | * CAP_SYS_ADMIN for setting opaque xattr | |
417 | * CAP_DAC_OVERRIDE for create in workdir, rename | |
418 | * CAP_FOWNER for removing whiteout from sticky dir | |
419 | */ | |
420 | cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN); | |
421 | cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); | |
422 | cap_raise(override_cred->cap_effective, CAP_FOWNER); | |
423 | old_cred = override_creds(override_cred); | |
424 | ||
425 | err = ovl_create_over_whiteout(dentry, inode, &stat, link, | |
426 | hardlink); | |
427 | ||
428 | revert_creds(old_cred); | |
429 | put_cred(override_cred); | |
430 | } | |
431 | ||
432 | if (!err) | |
433 | inode = NULL; | |
434 | out_iput: | |
435 | iput(inode); | |
436 | out: | |
437 | return err; | |
438 | } | |
439 | ||
440 | static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, | |
441 | const char *link) | |
442 | { | |
443 | int err; | |
444 | ||
445 | err = ovl_want_write(dentry); | |
446 | if (!err) { | |
447 | err = ovl_create_or_link(dentry, mode, rdev, link, NULL); | |
448 | ovl_drop_write(dentry); | |
449 | } | |
450 | ||
451 | return err; | |
452 | } | |
453 | ||
454 | static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode, | |
455 | bool excl) | |
456 | { | |
457 | return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL); | |
458 | } | |
459 | ||
460 | static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) | |
461 | { | |
462 | return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL); | |
463 | } | |
464 | ||
465 | static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, | |
466 | dev_t rdev) | |
467 | { | |
468 | /* Don't allow creation of "whiteout" on overlay */ | |
469 | if (S_ISCHR(mode) && rdev == WHITEOUT_DEV) | |
470 | return -EPERM; | |
471 | ||
472 | return ovl_create_object(dentry, mode, rdev, NULL); | |
473 | } | |
474 | ||
475 | static int ovl_symlink(struct inode *dir, struct dentry *dentry, | |
476 | const char *link) | |
477 | { | |
478 | return ovl_create_object(dentry, S_IFLNK, 0, link); | |
479 | } | |
480 | ||
481 | static int ovl_link(struct dentry *old, struct inode *newdir, | |
482 | struct dentry *new) | |
483 | { | |
484 | int err; | |
485 | struct dentry *upper; | |
486 | ||
487 | err = ovl_want_write(old); | |
488 | if (err) | |
489 | goto out; | |
490 | ||
491 | err = ovl_copy_up(old); | |
492 | if (err) | |
493 | goto out_drop_write; | |
494 | ||
495 | upper = ovl_dentry_upper(old); | |
496 | err = ovl_create_or_link(new, upper->d_inode->i_mode, 0, NULL, upper); | |
497 | ||
498 | out_drop_write: | |
499 | ovl_drop_write(old); | |
500 | out: | |
501 | return err; | |
502 | } | |
503 | ||
a105d685 | 504 | static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir) |
e9be9d5e MS |
505 | { |
506 | struct dentry *workdir = ovl_workdir(dentry); | |
507 | struct inode *wdir = workdir->d_inode; | |
508 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
509 | struct inode *udir = upperdir->d_inode; | |
510 | struct dentry *whiteout; | |
511 | struct dentry *upper; | |
512 | struct dentry *opaquedir = NULL; | |
513 | int err; | |
514 | ||
cc6f67bc MS |
515 | if (WARN_ON(!workdir)) |
516 | return -EROFS; | |
517 | ||
d377c5eb MS |
518 | if (is_dir) { |
519 | if (OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) { | |
520 | opaquedir = ovl_check_empty_and_clear(dentry); | |
521 | err = PTR_ERR(opaquedir); | |
522 | if (IS_ERR(opaquedir)) | |
523 | goto out; | |
524 | } else { | |
525 | LIST_HEAD(list); | |
526 | ||
527 | /* | |
528 | * When removing an empty opaque directory, then it | |
529 | * makes no sense to replace it with an exact replica of | |
530 | * itself. But emptiness still needs to be checked. | |
531 | */ | |
532 | err = ovl_check_empty_dir(dentry, &list); | |
533 | ovl_cache_free(&list); | |
534 | if (err) | |
535 | goto out; | |
536 | } | |
e9be9d5e MS |
537 | } |
538 | ||
539 | err = ovl_lock_rename_workdir(workdir, upperdir); | |
540 | if (err) | |
541 | goto out_dput; | |
542 | ||
543 | whiteout = ovl_whiteout(workdir, dentry); | |
544 | err = PTR_ERR(whiteout); | |
545 | if (IS_ERR(whiteout)) | |
546 | goto out_unlock; | |
547 | ||
a105d685 MS |
548 | upper = ovl_dentry_upper(dentry); |
549 | if (!upper) { | |
e9be9d5e | 550 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
a105d685 | 551 | dentry->d_name.len); |
e9be9d5e MS |
552 | err = PTR_ERR(upper); |
553 | if (IS_ERR(upper)) | |
554 | goto kill_whiteout; | |
555 | ||
556 | err = ovl_do_rename(wdir, whiteout, udir, upper, 0); | |
557 | dput(upper); | |
558 | if (err) | |
559 | goto kill_whiteout; | |
560 | } else { | |
561 | int flags = 0; | |
562 | ||
e9be9d5e MS |
563 | if (opaquedir) |
564 | upper = opaquedir; | |
565 | err = -ESTALE; | |
566 | if (upper->d_parent != upperdir) | |
567 | goto kill_whiteout; | |
568 | ||
569 | if (is_dir) | |
570 | flags |= RENAME_EXCHANGE; | |
571 | ||
572 | err = ovl_do_rename(wdir, whiteout, udir, upper, flags); | |
573 | if (err) | |
574 | goto kill_whiteout; | |
575 | ||
576 | if (is_dir) | |
577 | ovl_cleanup(wdir, upper); | |
578 | } | |
579 | ovl_dentry_version_inc(dentry->d_parent); | |
580 | out_d_drop: | |
581 | d_drop(dentry); | |
582 | dput(whiteout); | |
583 | out_unlock: | |
584 | unlock_rename(workdir, upperdir); | |
585 | out_dput: | |
586 | dput(opaquedir); | |
587 | out: | |
588 | return err; | |
589 | ||
590 | kill_whiteout: | |
591 | ovl_cleanup(wdir, whiteout); | |
592 | goto out_d_drop; | |
593 | } | |
594 | ||
595 | static int ovl_remove_upper(struct dentry *dentry, bool is_dir) | |
596 | { | |
597 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
598 | struct inode *dir = upperdir->d_inode; | |
599 | struct dentry *upper = ovl_dentry_upper(dentry); | |
600 | int err; | |
601 | ||
602 | mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT); | |
603 | err = -ESTALE; | |
604 | if (upper->d_parent == upperdir) { | |
605 | /* Don't let d_delete() think it can reset d_inode */ | |
606 | dget(upper); | |
607 | if (is_dir) | |
608 | err = vfs_rmdir(dir, upper); | |
609 | else | |
610 | err = vfs_unlink(dir, upper, NULL); | |
611 | dput(upper); | |
612 | ovl_dentry_version_inc(dentry->d_parent); | |
613 | } | |
614 | ||
615 | /* | |
616 | * Keeping this dentry hashed would mean having to release | |
617 | * upperpath/lowerpath, which could only be done if we are the | |
618 | * sole user of this dentry. Too tricky... Just unhash for | |
619 | * now. | |
620 | */ | |
621 | d_drop(dentry); | |
622 | mutex_unlock(&dir->i_mutex); | |
623 | ||
624 | return err; | |
625 | } | |
626 | ||
627 | static inline int ovl_check_sticky(struct dentry *dentry) | |
628 | { | |
629 | struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode; | |
630 | struct inode *inode = ovl_dentry_real(dentry)->d_inode; | |
631 | ||
632 | if (check_sticky(dir, inode)) | |
633 | return -EPERM; | |
634 | ||
635 | return 0; | |
636 | } | |
637 | ||
638 | static int ovl_do_remove(struct dentry *dentry, bool is_dir) | |
639 | { | |
640 | enum ovl_path_type type; | |
641 | int err; | |
642 | ||
643 | err = ovl_check_sticky(dentry); | |
644 | if (err) | |
645 | goto out; | |
646 | ||
647 | err = ovl_want_write(dentry); | |
648 | if (err) | |
649 | goto out; | |
650 | ||
651 | err = ovl_copy_up(dentry->d_parent); | |
652 | if (err) | |
653 | goto out_drop_write; | |
654 | ||
655 | type = ovl_path_type(dentry); | |
1afaba1e | 656 | if (OVL_TYPE_PURE_UPPER(type)) { |
e9be9d5e MS |
657 | err = ovl_remove_upper(dentry, is_dir); |
658 | } else { | |
659 | const struct cred *old_cred; | |
660 | struct cred *override_cred; | |
661 | ||
662 | err = -ENOMEM; | |
663 | override_cred = prepare_creds(); | |
664 | if (!override_cred) | |
665 | goto out_drop_write; | |
666 | ||
667 | /* | |
668 | * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir | |
669 | * CAP_DAC_OVERRIDE for create in workdir, rename | |
670 | * CAP_FOWNER for removing whiteout from sticky dir | |
671 | * CAP_FSETID for chmod of opaque dir | |
672 | * CAP_CHOWN for chown of opaque dir | |
673 | */ | |
674 | cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN); | |
675 | cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); | |
676 | cap_raise(override_cred->cap_effective, CAP_FOWNER); | |
677 | cap_raise(override_cred->cap_effective, CAP_FSETID); | |
678 | cap_raise(override_cred->cap_effective, CAP_CHOWN); | |
679 | old_cred = override_creds(override_cred); | |
680 | ||
a105d685 | 681 | err = ovl_remove_and_whiteout(dentry, is_dir); |
e9be9d5e MS |
682 | |
683 | revert_creds(old_cred); | |
684 | put_cred(override_cred); | |
685 | } | |
686 | out_drop_write: | |
687 | ovl_drop_write(dentry); | |
688 | out: | |
689 | return err; | |
690 | } | |
691 | ||
692 | static int ovl_unlink(struct inode *dir, struct dentry *dentry) | |
693 | { | |
694 | return ovl_do_remove(dentry, false); | |
695 | } | |
696 | ||
697 | static int ovl_rmdir(struct inode *dir, struct dentry *dentry) | |
698 | { | |
699 | return ovl_do_remove(dentry, true); | |
700 | } | |
701 | ||
702 | static int ovl_rename2(struct inode *olddir, struct dentry *old, | |
703 | struct inode *newdir, struct dentry *new, | |
704 | unsigned int flags) | |
705 | { | |
706 | int err; | |
707 | enum ovl_path_type old_type; | |
708 | enum ovl_path_type new_type; | |
709 | struct dentry *old_upperdir; | |
710 | struct dentry *new_upperdir; | |
711 | struct dentry *olddentry; | |
712 | struct dentry *newdentry; | |
713 | struct dentry *trap; | |
714 | bool old_opaque; | |
715 | bool new_opaque; | |
716 | bool new_create = false; | |
717 | bool cleanup_whiteout = false; | |
718 | bool overwrite = !(flags & RENAME_EXCHANGE); | |
e36cb0b8 | 719 | bool is_dir = d_is_dir(old); |
e9be9d5e MS |
720 | bool new_is_dir = false; |
721 | struct dentry *opaquedir = NULL; | |
722 | const struct cred *old_cred = NULL; | |
723 | struct cred *override_cred = NULL; | |
724 | ||
725 | err = -EINVAL; | |
726 | if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) | |
727 | goto out; | |
728 | ||
729 | flags &= ~RENAME_NOREPLACE; | |
730 | ||
731 | err = ovl_check_sticky(old); | |
732 | if (err) | |
733 | goto out; | |
734 | ||
735 | /* Don't copy up directory trees */ | |
736 | old_type = ovl_path_type(old); | |
737 | err = -EXDEV; | |
1afaba1e | 738 | if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir) |
e9be9d5e MS |
739 | goto out; |
740 | ||
741 | if (new->d_inode) { | |
742 | err = ovl_check_sticky(new); | |
743 | if (err) | |
744 | goto out; | |
745 | ||
e36cb0b8 | 746 | if (d_is_dir(new)) |
e9be9d5e MS |
747 | new_is_dir = true; |
748 | ||
749 | new_type = ovl_path_type(new); | |
750 | err = -EXDEV; | |
1afaba1e | 751 | if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) |
e9be9d5e MS |
752 | goto out; |
753 | ||
754 | err = 0; | |
1afaba1e | 755 | if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) { |
e9be9d5e MS |
756 | if (ovl_dentry_lower(old)->d_inode == |
757 | ovl_dentry_lower(new)->d_inode) | |
758 | goto out; | |
759 | } | |
1afaba1e | 760 | if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) { |
e9be9d5e MS |
761 | if (ovl_dentry_upper(old)->d_inode == |
762 | ovl_dentry_upper(new)->d_inode) | |
763 | goto out; | |
764 | } | |
765 | } else { | |
766 | if (ovl_dentry_is_opaque(new)) | |
1afaba1e | 767 | new_type = __OVL_PATH_UPPER; |
e9be9d5e | 768 | else |
1afaba1e | 769 | new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE; |
e9be9d5e MS |
770 | } |
771 | ||
772 | err = ovl_want_write(old); | |
773 | if (err) | |
774 | goto out; | |
775 | ||
776 | err = ovl_copy_up(old); | |
777 | if (err) | |
778 | goto out_drop_write; | |
779 | ||
780 | err = ovl_copy_up(new->d_parent); | |
781 | if (err) | |
782 | goto out_drop_write; | |
783 | if (!overwrite) { | |
784 | err = ovl_copy_up(new); | |
785 | if (err) | |
786 | goto out_drop_write; | |
787 | } | |
788 | ||
1afaba1e MS |
789 | old_opaque = !OVL_TYPE_PURE_UPPER(old_type); |
790 | new_opaque = !OVL_TYPE_PURE_UPPER(new_type); | |
e9be9d5e MS |
791 | |
792 | if (old_opaque || new_opaque) { | |
793 | err = -ENOMEM; | |
794 | override_cred = prepare_creds(); | |
795 | if (!override_cred) | |
796 | goto out_drop_write; | |
797 | ||
798 | /* | |
799 | * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir | |
800 | * CAP_DAC_OVERRIDE for create in workdir | |
801 | * CAP_FOWNER for removing whiteout from sticky dir | |
802 | * CAP_FSETID for chmod of opaque dir | |
803 | * CAP_CHOWN for chown of opaque dir | |
804 | */ | |
805 | cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN); | |
806 | cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); | |
807 | cap_raise(override_cred->cap_effective, CAP_FOWNER); | |
808 | cap_raise(override_cred->cap_effective, CAP_FSETID); | |
809 | cap_raise(override_cred->cap_effective, CAP_CHOWN); | |
810 | old_cred = override_creds(override_cred); | |
811 | } | |
812 | ||
1afaba1e | 813 | if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) { |
a105d685 | 814 | opaquedir = ovl_check_empty_and_clear(new); |
e9be9d5e MS |
815 | err = PTR_ERR(opaquedir); |
816 | if (IS_ERR(opaquedir)) { | |
817 | opaquedir = NULL; | |
818 | goto out_revert_creds; | |
819 | } | |
820 | } | |
821 | ||
822 | if (overwrite) { | |
823 | if (old_opaque) { | |
824 | if (new->d_inode || !new_opaque) { | |
825 | /* Whiteout source */ | |
826 | flags |= RENAME_WHITEOUT; | |
827 | } else { | |
828 | /* Switch whiteouts */ | |
829 | flags |= RENAME_EXCHANGE; | |
830 | } | |
831 | } else if (is_dir && !new->d_inode && new_opaque) { | |
832 | flags |= RENAME_EXCHANGE; | |
833 | cleanup_whiteout = true; | |
834 | } | |
835 | } | |
836 | ||
837 | old_upperdir = ovl_dentry_upper(old->d_parent); | |
838 | new_upperdir = ovl_dentry_upper(new->d_parent); | |
839 | ||
840 | trap = lock_rename(new_upperdir, old_upperdir); | |
841 | ||
842 | olddentry = ovl_dentry_upper(old); | |
843 | newdentry = ovl_dentry_upper(new); | |
844 | if (newdentry) { | |
845 | if (opaquedir) { | |
846 | newdentry = opaquedir; | |
847 | opaquedir = NULL; | |
848 | } else { | |
849 | dget(newdentry); | |
850 | } | |
851 | } else { | |
852 | new_create = true; | |
853 | newdentry = lookup_one_len(new->d_name.name, new_upperdir, | |
854 | new->d_name.len); | |
855 | err = PTR_ERR(newdentry); | |
856 | if (IS_ERR(newdentry)) | |
857 | goto out_unlock; | |
858 | } | |
859 | ||
860 | err = -ESTALE; | |
861 | if (olddentry->d_parent != old_upperdir) | |
862 | goto out_dput; | |
863 | if (newdentry->d_parent != new_upperdir) | |
864 | goto out_dput; | |
865 | if (olddentry == trap) | |
866 | goto out_dput; | |
867 | if (newdentry == trap) | |
868 | goto out_dput; | |
869 | ||
870 | if (is_dir && !old_opaque && new_opaque) { | |
871 | err = ovl_set_opaque(olddentry); | |
872 | if (err) | |
873 | goto out_dput; | |
874 | } | |
875 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) { | |
876 | err = ovl_set_opaque(newdentry); | |
877 | if (err) | |
878 | goto out_dput; | |
879 | } | |
880 | ||
881 | if (old_opaque || new_opaque) { | |
882 | err = ovl_do_rename(old_upperdir->d_inode, olddentry, | |
883 | new_upperdir->d_inode, newdentry, | |
884 | flags); | |
885 | } else { | |
886 | /* No debug for the plain case */ | |
887 | BUG_ON(flags & ~RENAME_EXCHANGE); | |
888 | err = vfs_rename(old_upperdir->d_inode, olddentry, | |
889 | new_upperdir->d_inode, newdentry, | |
890 | NULL, flags); | |
891 | } | |
892 | ||
893 | if (err) { | |
894 | if (is_dir && !old_opaque && new_opaque) | |
895 | ovl_remove_opaque(olddentry); | |
896 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) | |
897 | ovl_remove_opaque(newdentry); | |
898 | goto out_dput; | |
899 | } | |
900 | ||
901 | if (is_dir && old_opaque && !new_opaque) | |
902 | ovl_remove_opaque(olddentry); | |
903 | if (!overwrite && new_is_dir && !old_opaque && new_opaque) | |
904 | ovl_remove_opaque(newdentry); | |
905 | ||
906 | if (old_opaque != new_opaque) { | |
907 | ovl_dentry_set_opaque(old, new_opaque); | |
908 | if (!overwrite) | |
909 | ovl_dentry_set_opaque(new, old_opaque); | |
910 | } | |
911 | ||
912 | if (cleanup_whiteout) | |
913 | ovl_cleanup(old_upperdir->d_inode, newdentry); | |
914 | ||
915 | ovl_dentry_version_inc(old->d_parent); | |
916 | ovl_dentry_version_inc(new->d_parent); | |
917 | ||
918 | out_dput: | |
919 | dput(newdentry); | |
920 | out_unlock: | |
921 | unlock_rename(new_upperdir, old_upperdir); | |
922 | out_revert_creds: | |
923 | if (old_opaque || new_opaque) { | |
924 | revert_creds(old_cred); | |
925 | put_cred(override_cred); | |
926 | } | |
927 | out_drop_write: | |
928 | ovl_drop_write(old); | |
929 | out: | |
930 | dput(opaquedir); | |
931 | return err; | |
932 | } | |
933 | ||
934 | const struct inode_operations ovl_dir_inode_operations = { | |
935 | .lookup = ovl_lookup, | |
936 | .mkdir = ovl_mkdir, | |
937 | .symlink = ovl_symlink, | |
938 | .unlink = ovl_unlink, | |
939 | .rmdir = ovl_rmdir, | |
940 | .rename2 = ovl_rename2, | |
941 | .link = ovl_link, | |
942 | .setattr = ovl_setattr, | |
943 | .create = ovl_create, | |
944 | .mknod = ovl_mknod, | |
945 | .permission = ovl_permission, | |
946 | .getattr = ovl_dir_getattr, | |
947 | .setxattr = ovl_setxattr, | |
948 | .getxattr = ovl_getxattr, | |
949 | .listxattr = ovl_listxattr, | |
950 | .removexattr = ovl_removexattr, | |
951 | }; |