]>
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); | |
22 | if (S_ISDIR(wdentry->d_inode->i_mode)) | |
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 | ||
225 | err = ovl_lock_rename_workdir(workdir, upperdir); | |
226 | if (err) | |
227 | goto out; | |
228 | ||
229 | ovl_path_upper(dentry, &upperpath); | |
230 | err = vfs_getattr(&upperpath, &stat); | |
231 | if (err) | |
232 | goto out_unlock; | |
233 | ||
234 | err = -ESTALE; | |
235 | if (!S_ISDIR(stat.mode)) | |
236 | goto out_unlock; | |
237 | upper = upperpath.dentry; | |
238 | if (upper->d_parent->d_inode != udir) | |
239 | goto out_unlock; | |
240 | ||
241 | opaquedir = ovl_lookup_temp(workdir, dentry); | |
242 | err = PTR_ERR(opaquedir); | |
243 | if (IS_ERR(opaquedir)) | |
244 | goto out_unlock; | |
245 | ||
246 | err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true); | |
247 | if (err) | |
248 | goto out_dput; | |
249 | ||
250 | err = ovl_copy_xattr(upper, opaquedir); | |
251 | if (err) | |
252 | goto out_cleanup; | |
253 | ||
254 | err = ovl_set_opaque(opaquedir); | |
255 | if (err) | |
256 | goto out_cleanup; | |
257 | ||
258 | mutex_lock(&opaquedir->d_inode->i_mutex); | |
259 | err = ovl_set_attr(opaquedir, &stat); | |
260 | mutex_unlock(&opaquedir->d_inode->i_mutex); | |
261 | if (err) | |
262 | goto out_cleanup; | |
263 | ||
264 | err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE); | |
265 | if (err) | |
266 | goto out_cleanup; | |
267 | ||
268 | ovl_cleanup_whiteouts(upper, list); | |
269 | ovl_cleanup(wdir, upper); | |
270 | unlock_rename(workdir, upperdir); | |
271 | ||
272 | /* dentry's upper doesn't match now, get rid of it */ | |
273 | d_drop(dentry); | |
274 | ||
275 | return opaquedir; | |
276 | ||
277 | out_cleanup: | |
278 | ovl_cleanup(wdir, opaquedir); | |
279 | out_dput: | |
280 | dput(opaquedir); | |
281 | out_unlock: | |
282 | unlock_rename(workdir, upperdir); | |
283 | out: | |
284 | return ERR_PTR(err); | |
285 | } | |
286 | ||
a105d685 | 287 | static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry) |
e9be9d5e MS |
288 | { |
289 | int err; | |
290 | struct dentry *ret = NULL; | |
291 | LIST_HEAD(list); | |
292 | ||
293 | err = ovl_check_empty_dir(dentry, &list); | |
294 | if (err) | |
295 | ret = ERR_PTR(err); | |
a105d685 MS |
296 | else { |
297 | /* | |
298 | * If no upperdentry then skip clearing whiteouts. | |
299 | * | |
300 | * Can race with copy-up, since we don't hold the upperdir | |
301 | * mutex. Doesn't matter, since copy-up can't create a | |
302 | * non-empty directory from an empty one. | |
303 | */ | |
304 | if (ovl_dentry_upper(dentry)) | |
305 | ret = ovl_clear_empty(dentry, &list); | |
306 | } | |
e9be9d5e MS |
307 | |
308 | ovl_cache_free(&list); | |
309 | ||
310 | return ret; | |
311 | } | |
312 | ||
313 | static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, | |
314 | struct kstat *stat, const char *link, | |
315 | struct dentry *hardlink) | |
316 | { | |
317 | struct dentry *workdir = ovl_workdir(dentry); | |
318 | struct inode *wdir = workdir->d_inode; | |
319 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
320 | struct inode *udir = upperdir->d_inode; | |
321 | struct dentry *upper; | |
322 | struct dentry *newdentry; | |
323 | int err; | |
324 | ||
325 | err = ovl_lock_rename_workdir(workdir, upperdir); | |
326 | if (err) | |
327 | goto out; | |
328 | ||
329 | newdentry = ovl_lookup_temp(workdir, dentry); | |
330 | err = PTR_ERR(newdentry); | |
331 | if (IS_ERR(newdentry)) | |
332 | goto out_unlock; | |
333 | ||
334 | upper = lookup_one_len(dentry->d_name.name, upperdir, | |
335 | dentry->d_name.len); | |
336 | err = PTR_ERR(upper); | |
337 | if (IS_ERR(upper)) | |
338 | goto out_dput; | |
339 | ||
340 | err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true); | |
341 | if (err) | |
342 | goto out_dput2; | |
343 | ||
344 | if (S_ISDIR(stat->mode)) { | |
345 | err = ovl_set_opaque(newdentry); | |
346 | if (err) | |
347 | goto out_cleanup; | |
348 | ||
349 | err = ovl_do_rename(wdir, newdentry, udir, upper, | |
350 | RENAME_EXCHANGE); | |
351 | if (err) | |
352 | goto out_cleanup; | |
353 | ||
354 | ovl_cleanup(wdir, upper); | |
355 | } else { | |
356 | err = ovl_do_rename(wdir, newdentry, udir, upper, 0); | |
357 | if (err) | |
358 | goto out_cleanup; | |
359 | } | |
360 | ovl_dentry_version_inc(dentry->d_parent); | |
361 | ovl_dentry_update(dentry, newdentry); | |
362 | ovl_copyattr(newdentry->d_inode, inode); | |
363 | d_instantiate(dentry, inode); | |
364 | newdentry = NULL; | |
365 | out_dput2: | |
366 | dput(upper); | |
367 | out_dput: | |
368 | dput(newdentry); | |
369 | out_unlock: | |
370 | unlock_rename(workdir, upperdir); | |
371 | out: | |
372 | return err; | |
373 | ||
374 | out_cleanup: | |
375 | ovl_cleanup(wdir, newdentry); | |
376 | goto out_dput2; | |
377 | } | |
378 | ||
379 | static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev, | |
380 | const char *link, struct dentry *hardlink) | |
381 | { | |
382 | int err; | |
383 | struct inode *inode; | |
384 | struct kstat stat = { | |
385 | .mode = mode, | |
386 | .rdev = rdev, | |
387 | }; | |
388 | ||
389 | err = -ENOMEM; | |
390 | inode = ovl_new_inode(dentry->d_sb, mode, dentry->d_fsdata); | |
391 | if (!inode) | |
392 | goto out; | |
393 | ||
394 | err = ovl_copy_up(dentry->d_parent); | |
395 | if (err) | |
396 | goto out_iput; | |
397 | ||
398 | if (!ovl_dentry_is_opaque(dentry)) { | |
399 | err = ovl_create_upper(dentry, inode, &stat, link, hardlink); | |
400 | } else { | |
401 | const struct cred *old_cred; | |
402 | struct cred *override_cred; | |
403 | ||
404 | err = -ENOMEM; | |
405 | override_cred = prepare_creds(); | |
406 | if (!override_cred) | |
407 | goto out_iput; | |
408 | ||
409 | /* | |
410 | * CAP_SYS_ADMIN for setting opaque xattr | |
411 | * CAP_DAC_OVERRIDE for create in workdir, rename | |
412 | * CAP_FOWNER for removing whiteout from sticky dir | |
413 | */ | |
414 | cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN); | |
415 | cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); | |
416 | cap_raise(override_cred->cap_effective, CAP_FOWNER); | |
417 | old_cred = override_creds(override_cred); | |
418 | ||
419 | err = ovl_create_over_whiteout(dentry, inode, &stat, link, | |
420 | hardlink); | |
421 | ||
422 | revert_creds(old_cred); | |
423 | put_cred(override_cred); | |
424 | } | |
425 | ||
426 | if (!err) | |
427 | inode = NULL; | |
428 | out_iput: | |
429 | iput(inode); | |
430 | out: | |
431 | return err; | |
432 | } | |
433 | ||
434 | static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, | |
435 | const char *link) | |
436 | { | |
437 | int err; | |
438 | ||
439 | err = ovl_want_write(dentry); | |
440 | if (!err) { | |
441 | err = ovl_create_or_link(dentry, mode, rdev, link, NULL); | |
442 | ovl_drop_write(dentry); | |
443 | } | |
444 | ||
445 | return err; | |
446 | } | |
447 | ||
448 | static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode, | |
449 | bool excl) | |
450 | { | |
451 | return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL); | |
452 | } | |
453 | ||
454 | static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) | |
455 | { | |
456 | return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL); | |
457 | } | |
458 | ||
459 | static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, | |
460 | dev_t rdev) | |
461 | { | |
462 | /* Don't allow creation of "whiteout" on overlay */ | |
463 | if (S_ISCHR(mode) && rdev == WHITEOUT_DEV) | |
464 | return -EPERM; | |
465 | ||
466 | return ovl_create_object(dentry, mode, rdev, NULL); | |
467 | } | |
468 | ||
469 | static int ovl_symlink(struct inode *dir, struct dentry *dentry, | |
470 | const char *link) | |
471 | { | |
472 | return ovl_create_object(dentry, S_IFLNK, 0, link); | |
473 | } | |
474 | ||
475 | static int ovl_link(struct dentry *old, struct inode *newdir, | |
476 | struct dentry *new) | |
477 | { | |
478 | int err; | |
479 | struct dentry *upper; | |
480 | ||
481 | err = ovl_want_write(old); | |
482 | if (err) | |
483 | goto out; | |
484 | ||
485 | err = ovl_copy_up(old); | |
486 | if (err) | |
487 | goto out_drop_write; | |
488 | ||
489 | upper = ovl_dentry_upper(old); | |
490 | err = ovl_create_or_link(new, upper->d_inode->i_mode, 0, NULL, upper); | |
491 | ||
492 | out_drop_write: | |
493 | ovl_drop_write(old); | |
494 | out: | |
495 | return err; | |
496 | } | |
497 | ||
a105d685 | 498 | static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir) |
e9be9d5e MS |
499 | { |
500 | struct dentry *workdir = ovl_workdir(dentry); | |
501 | struct inode *wdir = workdir->d_inode; | |
502 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
503 | struct inode *udir = upperdir->d_inode; | |
504 | struct dentry *whiteout; | |
505 | struct dentry *upper; | |
506 | struct dentry *opaquedir = NULL; | |
507 | int err; | |
508 | ||
263b4a0f | 509 | if (is_dir && OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) { |
a105d685 | 510 | opaquedir = ovl_check_empty_and_clear(dentry); |
e9be9d5e MS |
511 | err = PTR_ERR(opaquedir); |
512 | if (IS_ERR(opaquedir)) | |
513 | goto out; | |
514 | } | |
515 | ||
516 | err = ovl_lock_rename_workdir(workdir, upperdir); | |
517 | if (err) | |
518 | goto out_dput; | |
519 | ||
520 | whiteout = ovl_whiteout(workdir, dentry); | |
521 | err = PTR_ERR(whiteout); | |
522 | if (IS_ERR(whiteout)) | |
523 | goto out_unlock; | |
524 | ||
a105d685 MS |
525 | upper = ovl_dentry_upper(dentry); |
526 | if (!upper) { | |
e9be9d5e | 527 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
a105d685 | 528 | dentry->d_name.len); |
e9be9d5e MS |
529 | err = PTR_ERR(upper); |
530 | if (IS_ERR(upper)) | |
531 | goto kill_whiteout; | |
532 | ||
533 | err = ovl_do_rename(wdir, whiteout, udir, upper, 0); | |
534 | dput(upper); | |
535 | if (err) | |
536 | goto kill_whiteout; | |
537 | } else { | |
538 | int flags = 0; | |
539 | ||
e9be9d5e MS |
540 | if (opaquedir) |
541 | upper = opaquedir; | |
542 | err = -ESTALE; | |
543 | if (upper->d_parent != upperdir) | |
544 | goto kill_whiteout; | |
545 | ||
546 | if (is_dir) | |
547 | flags |= RENAME_EXCHANGE; | |
548 | ||
549 | err = ovl_do_rename(wdir, whiteout, udir, upper, flags); | |
550 | if (err) | |
551 | goto kill_whiteout; | |
552 | ||
553 | if (is_dir) | |
554 | ovl_cleanup(wdir, upper); | |
555 | } | |
556 | ovl_dentry_version_inc(dentry->d_parent); | |
557 | out_d_drop: | |
558 | d_drop(dentry); | |
559 | dput(whiteout); | |
560 | out_unlock: | |
561 | unlock_rename(workdir, upperdir); | |
562 | out_dput: | |
563 | dput(opaquedir); | |
564 | out: | |
565 | return err; | |
566 | ||
567 | kill_whiteout: | |
568 | ovl_cleanup(wdir, whiteout); | |
569 | goto out_d_drop; | |
570 | } | |
571 | ||
572 | static int ovl_remove_upper(struct dentry *dentry, bool is_dir) | |
573 | { | |
574 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
575 | struct inode *dir = upperdir->d_inode; | |
576 | struct dentry *upper = ovl_dentry_upper(dentry); | |
577 | int err; | |
578 | ||
579 | mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT); | |
580 | err = -ESTALE; | |
581 | if (upper->d_parent == upperdir) { | |
582 | /* Don't let d_delete() think it can reset d_inode */ | |
583 | dget(upper); | |
584 | if (is_dir) | |
585 | err = vfs_rmdir(dir, upper); | |
586 | else | |
587 | err = vfs_unlink(dir, upper, NULL); | |
588 | dput(upper); | |
589 | ovl_dentry_version_inc(dentry->d_parent); | |
590 | } | |
591 | ||
592 | /* | |
593 | * Keeping this dentry hashed would mean having to release | |
594 | * upperpath/lowerpath, which could only be done if we are the | |
595 | * sole user of this dentry. Too tricky... Just unhash for | |
596 | * now. | |
597 | */ | |
598 | d_drop(dentry); | |
599 | mutex_unlock(&dir->i_mutex); | |
600 | ||
601 | return err; | |
602 | } | |
603 | ||
604 | static inline int ovl_check_sticky(struct dentry *dentry) | |
605 | { | |
606 | struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode; | |
607 | struct inode *inode = ovl_dentry_real(dentry)->d_inode; | |
608 | ||
609 | if (check_sticky(dir, inode)) | |
610 | return -EPERM; | |
611 | ||
612 | return 0; | |
613 | } | |
614 | ||
615 | static int ovl_do_remove(struct dentry *dentry, bool is_dir) | |
616 | { | |
617 | enum ovl_path_type type; | |
618 | int err; | |
619 | ||
620 | err = ovl_check_sticky(dentry); | |
621 | if (err) | |
622 | goto out; | |
623 | ||
624 | err = ovl_want_write(dentry); | |
625 | if (err) | |
626 | goto out; | |
627 | ||
628 | err = ovl_copy_up(dentry->d_parent); | |
629 | if (err) | |
630 | goto out_drop_write; | |
631 | ||
632 | type = ovl_path_type(dentry); | |
1afaba1e | 633 | if (OVL_TYPE_PURE_UPPER(type)) { |
e9be9d5e MS |
634 | err = ovl_remove_upper(dentry, is_dir); |
635 | } else { | |
636 | const struct cred *old_cred; | |
637 | struct cred *override_cred; | |
638 | ||
639 | err = -ENOMEM; | |
640 | override_cred = prepare_creds(); | |
641 | if (!override_cred) | |
642 | goto out_drop_write; | |
643 | ||
644 | /* | |
645 | * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir | |
646 | * CAP_DAC_OVERRIDE for create in workdir, rename | |
647 | * CAP_FOWNER for removing whiteout from sticky dir | |
648 | * CAP_FSETID for chmod of opaque dir | |
649 | * CAP_CHOWN for chown of opaque dir | |
650 | */ | |
651 | cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN); | |
652 | cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); | |
653 | cap_raise(override_cred->cap_effective, CAP_FOWNER); | |
654 | cap_raise(override_cred->cap_effective, CAP_FSETID); | |
655 | cap_raise(override_cred->cap_effective, CAP_CHOWN); | |
656 | old_cred = override_creds(override_cred); | |
657 | ||
a105d685 | 658 | err = ovl_remove_and_whiteout(dentry, is_dir); |
e9be9d5e MS |
659 | |
660 | revert_creds(old_cred); | |
661 | put_cred(override_cred); | |
662 | } | |
663 | out_drop_write: | |
664 | ovl_drop_write(dentry); | |
665 | out: | |
666 | return err; | |
667 | } | |
668 | ||
669 | static int ovl_unlink(struct inode *dir, struct dentry *dentry) | |
670 | { | |
671 | return ovl_do_remove(dentry, false); | |
672 | } | |
673 | ||
674 | static int ovl_rmdir(struct inode *dir, struct dentry *dentry) | |
675 | { | |
676 | return ovl_do_remove(dentry, true); | |
677 | } | |
678 | ||
679 | static int ovl_rename2(struct inode *olddir, struct dentry *old, | |
680 | struct inode *newdir, struct dentry *new, | |
681 | unsigned int flags) | |
682 | { | |
683 | int err; | |
684 | enum ovl_path_type old_type; | |
685 | enum ovl_path_type new_type; | |
686 | struct dentry *old_upperdir; | |
687 | struct dentry *new_upperdir; | |
688 | struct dentry *olddentry; | |
689 | struct dentry *newdentry; | |
690 | struct dentry *trap; | |
691 | bool old_opaque; | |
692 | bool new_opaque; | |
693 | bool new_create = false; | |
694 | bool cleanup_whiteout = false; | |
695 | bool overwrite = !(flags & RENAME_EXCHANGE); | |
696 | bool is_dir = S_ISDIR(old->d_inode->i_mode); | |
697 | bool new_is_dir = false; | |
698 | struct dentry *opaquedir = NULL; | |
699 | const struct cred *old_cred = NULL; | |
700 | struct cred *override_cred = NULL; | |
701 | ||
702 | err = -EINVAL; | |
703 | if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) | |
704 | goto out; | |
705 | ||
706 | flags &= ~RENAME_NOREPLACE; | |
707 | ||
708 | err = ovl_check_sticky(old); | |
709 | if (err) | |
710 | goto out; | |
711 | ||
712 | /* Don't copy up directory trees */ | |
713 | old_type = ovl_path_type(old); | |
714 | err = -EXDEV; | |
1afaba1e | 715 | if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir) |
e9be9d5e MS |
716 | goto out; |
717 | ||
718 | if (new->d_inode) { | |
719 | err = ovl_check_sticky(new); | |
720 | if (err) | |
721 | goto out; | |
722 | ||
723 | if (S_ISDIR(new->d_inode->i_mode)) | |
724 | new_is_dir = true; | |
725 | ||
726 | new_type = ovl_path_type(new); | |
727 | err = -EXDEV; | |
1afaba1e | 728 | if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) |
e9be9d5e MS |
729 | goto out; |
730 | ||
731 | err = 0; | |
1afaba1e | 732 | if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) { |
e9be9d5e MS |
733 | if (ovl_dentry_lower(old)->d_inode == |
734 | ovl_dentry_lower(new)->d_inode) | |
735 | goto out; | |
736 | } | |
1afaba1e | 737 | if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) { |
e9be9d5e MS |
738 | if (ovl_dentry_upper(old)->d_inode == |
739 | ovl_dentry_upper(new)->d_inode) | |
740 | goto out; | |
741 | } | |
742 | } else { | |
743 | if (ovl_dentry_is_opaque(new)) | |
1afaba1e | 744 | new_type = __OVL_PATH_UPPER; |
e9be9d5e | 745 | else |
1afaba1e | 746 | new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE; |
e9be9d5e MS |
747 | } |
748 | ||
749 | err = ovl_want_write(old); | |
750 | if (err) | |
751 | goto out; | |
752 | ||
753 | err = ovl_copy_up(old); | |
754 | if (err) | |
755 | goto out_drop_write; | |
756 | ||
757 | err = ovl_copy_up(new->d_parent); | |
758 | if (err) | |
759 | goto out_drop_write; | |
760 | if (!overwrite) { | |
761 | err = ovl_copy_up(new); | |
762 | if (err) | |
763 | goto out_drop_write; | |
764 | } | |
765 | ||
1afaba1e MS |
766 | old_opaque = !OVL_TYPE_PURE_UPPER(old_type); |
767 | new_opaque = !OVL_TYPE_PURE_UPPER(new_type); | |
e9be9d5e MS |
768 | |
769 | if (old_opaque || new_opaque) { | |
770 | err = -ENOMEM; | |
771 | override_cred = prepare_creds(); | |
772 | if (!override_cred) | |
773 | goto out_drop_write; | |
774 | ||
775 | /* | |
776 | * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir | |
777 | * CAP_DAC_OVERRIDE for create in workdir | |
778 | * CAP_FOWNER for removing whiteout from sticky dir | |
779 | * CAP_FSETID for chmod of opaque dir | |
780 | * CAP_CHOWN for chown of opaque dir | |
781 | */ | |
782 | cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN); | |
783 | cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); | |
784 | cap_raise(override_cred->cap_effective, CAP_FOWNER); | |
785 | cap_raise(override_cred->cap_effective, CAP_FSETID); | |
786 | cap_raise(override_cred->cap_effective, CAP_CHOWN); | |
787 | old_cred = override_creds(override_cred); | |
788 | } | |
789 | ||
1afaba1e | 790 | if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) { |
a105d685 | 791 | opaquedir = ovl_check_empty_and_clear(new); |
e9be9d5e MS |
792 | err = PTR_ERR(opaquedir); |
793 | if (IS_ERR(opaquedir)) { | |
794 | opaquedir = NULL; | |
795 | goto out_revert_creds; | |
796 | } | |
797 | } | |
798 | ||
799 | if (overwrite) { | |
800 | if (old_opaque) { | |
801 | if (new->d_inode || !new_opaque) { | |
802 | /* Whiteout source */ | |
803 | flags |= RENAME_WHITEOUT; | |
804 | } else { | |
805 | /* Switch whiteouts */ | |
806 | flags |= RENAME_EXCHANGE; | |
807 | } | |
808 | } else if (is_dir && !new->d_inode && new_opaque) { | |
809 | flags |= RENAME_EXCHANGE; | |
810 | cleanup_whiteout = true; | |
811 | } | |
812 | } | |
813 | ||
814 | old_upperdir = ovl_dentry_upper(old->d_parent); | |
815 | new_upperdir = ovl_dentry_upper(new->d_parent); | |
816 | ||
817 | trap = lock_rename(new_upperdir, old_upperdir); | |
818 | ||
819 | olddentry = ovl_dentry_upper(old); | |
820 | newdentry = ovl_dentry_upper(new); | |
821 | if (newdentry) { | |
822 | if (opaquedir) { | |
823 | newdentry = opaquedir; | |
824 | opaquedir = NULL; | |
825 | } else { | |
826 | dget(newdentry); | |
827 | } | |
828 | } else { | |
829 | new_create = true; | |
830 | newdentry = lookup_one_len(new->d_name.name, new_upperdir, | |
831 | new->d_name.len); | |
832 | err = PTR_ERR(newdentry); | |
833 | if (IS_ERR(newdentry)) | |
834 | goto out_unlock; | |
835 | } | |
836 | ||
837 | err = -ESTALE; | |
838 | if (olddentry->d_parent != old_upperdir) | |
839 | goto out_dput; | |
840 | if (newdentry->d_parent != new_upperdir) | |
841 | goto out_dput; | |
842 | if (olddentry == trap) | |
843 | goto out_dput; | |
844 | if (newdentry == trap) | |
845 | goto out_dput; | |
846 | ||
847 | if (is_dir && !old_opaque && new_opaque) { | |
848 | err = ovl_set_opaque(olddentry); | |
849 | if (err) | |
850 | goto out_dput; | |
851 | } | |
852 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) { | |
853 | err = ovl_set_opaque(newdentry); | |
854 | if (err) | |
855 | goto out_dput; | |
856 | } | |
857 | ||
858 | if (old_opaque || new_opaque) { | |
859 | err = ovl_do_rename(old_upperdir->d_inode, olddentry, | |
860 | new_upperdir->d_inode, newdentry, | |
861 | flags); | |
862 | } else { | |
863 | /* No debug for the plain case */ | |
864 | BUG_ON(flags & ~RENAME_EXCHANGE); | |
865 | err = vfs_rename(old_upperdir->d_inode, olddentry, | |
866 | new_upperdir->d_inode, newdentry, | |
867 | NULL, flags); | |
868 | } | |
869 | ||
870 | if (err) { | |
871 | if (is_dir && !old_opaque && new_opaque) | |
872 | ovl_remove_opaque(olddentry); | |
873 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) | |
874 | ovl_remove_opaque(newdentry); | |
875 | goto out_dput; | |
876 | } | |
877 | ||
878 | if (is_dir && old_opaque && !new_opaque) | |
879 | ovl_remove_opaque(olddentry); | |
880 | if (!overwrite && new_is_dir && !old_opaque && new_opaque) | |
881 | ovl_remove_opaque(newdentry); | |
882 | ||
883 | if (old_opaque != new_opaque) { | |
884 | ovl_dentry_set_opaque(old, new_opaque); | |
885 | if (!overwrite) | |
886 | ovl_dentry_set_opaque(new, old_opaque); | |
887 | } | |
888 | ||
889 | if (cleanup_whiteout) | |
890 | ovl_cleanup(old_upperdir->d_inode, newdentry); | |
891 | ||
892 | ovl_dentry_version_inc(old->d_parent); | |
893 | ovl_dentry_version_inc(new->d_parent); | |
894 | ||
895 | out_dput: | |
896 | dput(newdentry); | |
897 | out_unlock: | |
898 | unlock_rename(new_upperdir, old_upperdir); | |
899 | out_revert_creds: | |
900 | if (old_opaque || new_opaque) { | |
901 | revert_creds(old_cred); | |
902 | put_cred(override_cred); | |
903 | } | |
904 | out_drop_write: | |
905 | ovl_drop_write(old); | |
906 | out: | |
907 | dput(opaquedir); | |
908 | return err; | |
909 | } | |
910 | ||
911 | const struct inode_operations ovl_dir_inode_operations = { | |
912 | .lookup = ovl_lookup, | |
913 | .mkdir = ovl_mkdir, | |
914 | .symlink = ovl_symlink, | |
915 | .unlink = ovl_unlink, | |
916 | .rmdir = ovl_rmdir, | |
917 | .rename2 = ovl_rename2, | |
918 | .link = ovl_link, | |
919 | .setattr = ovl_setattr, | |
920 | .create = ovl_create, | |
921 | .mknod = ovl_mknod, | |
922 | .permission = ovl_permission, | |
923 | .getattr = ovl_dir_getattr, | |
924 | .setxattr = ovl_setxattr, | |
925 | .getxattr = ovl_getxattr, | |
926 | .listxattr = ovl_listxattr, | |
927 | .removexattr = ovl_removexattr, | |
928 | }; |