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; | |
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; | |
11f37104 | 599 | struct dentry *upper; |
e9be9d5e MS |
600 | int err; |
601 | ||
5955102c | 602 | inode_lock_nested(dir, I_MUTEX_PARENT); |
11f37104 MS |
603 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
604 | dentry->d_name.len); | |
605 | err = PTR_ERR(upper); | |
606 | if (IS_ERR(upper)) | |
607 | goto out_unlock; | |
608 | ||
e9be9d5e | 609 | err = -ESTALE; |
11f37104 | 610 | if (upper == ovl_dentry_upper(dentry)) { |
e9be9d5e MS |
611 | if (is_dir) |
612 | err = vfs_rmdir(dir, upper); | |
613 | else | |
614 | err = vfs_unlink(dir, upper, NULL); | |
e9be9d5e MS |
615 | ovl_dentry_version_inc(dentry->d_parent); |
616 | } | |
11f37104 | 617 | dput(upper); |
e9be9d5e MS |
618 | |
619 | /* | |
620 | * Keeping this dentry hashed would mean having to release | |
621 | * upperpath/lowerpath, which could only be done if we are the | |
622 | * sole user of this dentry. Too tricky... Just unhash for | |
623 | * now. | |
624 | */ | |
ce9113bb RW |
625 | if (!err) |
626 | d_drop(dentry); | |
11f37104 | 627 | out_unlock: |
5955102c | 628 | inode_unlock(dir); |
e9be9d5e MS |
629 | |
630 | return err; | |
631 | } | |
632 | ||
633 | static inline int ovl_check_sticky(struct dentry *dentry) | |
634 | { | |
635 | struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode; | |
636 | struct inode *inode = ovl_dentry_real(dentry)->d_inode; | |
637 | ||
638 | if (check_sticky(dir, inode)) | |
639 | return -EPERM; | |
640 | ||
641 | return 0; | |
642 | } | |
643 | ||
644 | static int ovl_do_remove(struct dentry *dentry, bool is_dir) | |
645 | { | |
646 | enum ovl_path_type type; | |
647 | int err; | |
648 | ||
649 | err = ovl_check_sticky(dentry); | |
650 | if (err) | |
651 | goto out; | |
652 | ||
653 | err = ovl_want_write(dentry); | |
654 | if (err) | |
655 | goto out; | |
656 | ||
657 | err = ovl_copy_up(dentry->d_parent); | |
658 | if (err) | |
659 | goto out_drop_write; | |
660 | ||
661 | type = ovl_path_type(dentry); | |
1afaba1e | 662 | if (OVL_TYPE_PURE_UPPER(type)) { |
e9be9d5e MS |
663 | err = ovl_remove_upper(dentry, is_dir); |
664 | } else { | |
665 | const struct cred *old_cred; | |
666 | struct cred *override_cred; | |
667 | ||
668 | err = -ENOMEM; | |
669 | override_cred = prepare_creds(); | |
670 | if (!override_cred) | |
671 | goto out_drop_write; | |
672 | ||
673 | /* | |
674 | * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir | |
675 | * CAP_DAC_OVERRIDE for create in workdir, rename | |
676 | * CAP_FOWNER for removing whiteout from sticky dir | |
677 | * CAP_FSETID for chmod of opaque dir | |
678 | * CAP_CHOWN for chown of opaque dir | |
679 | */ | |
680 | cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN); | |
681 | cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); | |
682 | cap_raise(override_cred->cap_effective, CAP_FOWNER); | |
683 | cap_raise(override_cred->cap_effective, CAP_FSETID); | |
684 | cap_raise(override_cred->cap_effective, CAP_CHOWN); | |
685 | old_cred = override_creds(override_cred); | |
686 | ||
a105d685 | 687 | err = ovl_remove_and_whiteout(dentry, is_dir); |
e9be9d5e MS |
688 | |
689 | revert_creds(old_cred); | |
690 | put_cred(override_cred); | |
691 | } | |
692 | out_drop_write: | |
693 | ovl_drop_write(dentry); | |
694 | out: | |
695 | return err; | |
696 | } | |
697 | ||
698 | static int ovl_unlink(struct inode *dir, struct dentry *dentry) | |
699 | { | |
700 | return ovl_do_remove(dentry, false); | |
701 | } | |
702 | ||
703 | static int ovl_rmdir(struct inode *dir, struct dentry *dentry) | |
704 | { | |
705 | return ovl_do_remove(dentry, true); | |
706 | } | |
707 | ||
708 | static int ovl_rename2(struct inode *olddir, struct dentry *old, | |
709 | struct inode *newdir, struct dentry *new, | |
710 | unsigned int flags) | |
711 | { | |
712 | int err; | |
713 | enum ovl_path_type old_type; | |
714 | enum ovl_path_type new_type; | |
715 | struct dentry *old_upperdir; | |
716 | struct dentry *new_upperdir; | |
717 | struct dentry *olddentry; | |
718 | struct dentry *newdentry; | |
719 | struct dentry *trap; | |
720 | bool old_opaque; | |
721 | bool new_opaque; | |
e9be9d5e MS |
722 | bool cleanup_whiteout = false; |
723 | bool overwrite = !(flags & RENAME_EXCHANGE); | |
e36cb0b8 | 724 | bool is_dir = d_is_dir(old); |
e9be9d5e MS |
725 | bool new_is_dir = false; |
726 | struct dentry *opaquedir = NULL; | |
727 | const struct cred *old_cred = NULL; | |
728 | struct cred *override_cred = NULL; | |
729 | ||
730 | err = -EINVAL; | |
731 | if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) | |
732 | goto out; | |
733 | ||
734 | flags &= ~RENAME_NOREPLACE; | |
735 | ||
736 | err = ovl_check_sticky(old); | |
737 | if (err) | |
738 | goto out; | |
739 | ||
740 | /* Don't copy up directory trees */ | |
741 | old_type = ovl_path_type(old); | |
742 | err = -EXDEV; | |
1afaba1e | 743 | if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir) |
e9be9d5e MS |
744 | goto out; |
745 | ||
746 | if (new->d_inode) { | |
747 | err = ovl_check_sticky(new); | |
748 | if (err) | |
749 | goto out; | |
750 | ||
e36cb0b8 | 751 | if (d_is_dir(new)) |
e9be9d5e MS |
752 | new_is_dir = true; |
753 | ||
754 | new_type = ovl_path_type(new); | |
755 | err = -EXDEV; | |
1afaba1e | 756 | if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) |
e9be9d5e MS |
757 | goto out; |
758 | ||
759 | err = 0; | |
1afaba1e | 760 | if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) { |
e9be9d5e MS |
761 | if (ovl_dentry_lower(old)->d_inode == |
762 | ovl_dentry_lower(new)->d_inode) | |
763 | goto out; | |
764 | } | |
1afaba1e | 765 | if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) { |
e9be9d5e MS |
766 | if (ovl_dentry_upper(old)->d_inode == |
767 | ovl_dentry_upper(new)->d_inode) | |
768 | goto out; | |
769 | } | |
770 | } else { | |
771 | if (ovl_dentry_is_opaque(new)) | |
1afaba1e | 772 | new_type = __OVL_PATH_UPPER; |
e9be9d5e | 773 | else |
1afaba1e | 774 | new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE; |
e9be9d5e MS |
775 | } |
776 | ||
777 | err = ovl_want_write(old); | |
778 | if (err) | |
779 | goto out; | |
780 | ||
781 | err = ovl_copy_up(old); | |
782 | if (err) | |
783 | goto out_drop_write; | |
784 | ||
785 | err = ovl_copy_up(new->d_parent); | |
786 | if (err) | |
787 | goto out_drop_write; | |
788 | if (!overwrite) { | |
789 | err = ovl_copy_up(new); | |
790 | if (err) | |
791 | goto out_drop_write; | |
792 | } | |
793 | ||
1afaba1e MS |
794 | old_opaque = !OVL_TYPE_PURE_UPPER(old_type); |
795 | new_opaque = !OVL_TYPE_PURE_UPPER(new_type); | |
e9be9d5e MS |
796 | |
797 | if (old_opaque || new_opaque) { | |
798 | err = -ENOMEM; | |
799 | override_cred = prepare_creds(); | |
800 | if (!override_cred) | |
801 | goto out_drop_write; | |
802 | ||
803 | /* | |
804 | * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir | |
805 | * CAP_DAC_OVERRIDE for create in workdir | |
806 | * CAP_FOWNER for removing whiteout from sticky dir | |
807 | * CAP_FSETID for chmod of opaque dir | |
808 | * CAP_CHOWN for chown of opaque dir | |
809 | */ | |
810 | cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN); | |
811 | cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE); | |
812 | cap_raise(override_cred->cap_effective, CAP_FOWNER); | |
813 | cap_raise(override_cred->cap_effective, CAP_FSETID); | |
814 | cap_raise(override_cred->cap_effective, CAP_CHOWN); | |
815 | old_cred = override_creds(override_cred); | |
816 | } | |
817 | ||
1afaba1e | 818 | if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) { |
a105d685 | 819 | opaquedir = ovl_check_empty_and_clear(new); |
e9be9d5e MS |
820 | err = PTR_ERR(opaquedir); |
821 | if (IS_ERR(opaquedir)) { | |
822 | opaquedir = NULL; | |
823 | goto out_revert_creds; | |
824 | } | |
825 | } | |
826 | ||
827 | if (overwrite) { | |
828 | if (old_opaque) { | |
829 | if (new->d_inode || !new_opaque) { | |
830 | /* Whiteout source */ | |
831 | flags |= RENAME_WHITEOUT; | |
832 | } else { | |
833 | /* Switch whiteouts */ | |
834 | flags |= RENAME_EXCHANGE; | |
835 | } | |
836 | } else if (is_dir && !new->d_inode && new_opaque) { | |
837 | flags |= RENAME_EXCHANGE; | |
838 | cleanup_whiteout = true; | |
839 | } | |
840 | } | |
841 | ||
842 | old_upperdir = ovl_dentry_upper(old->d_parent); | |
843 | new_upperdir = ovl_dentry_upper(new->d_parent); | |
844 | ||
845 | trap = lock_rename(new_upperdir, old_upperdir); | |
846 | ||
11f37104 MS |
847 | |
848 | olddentry = lookup_one_len(old->d_name.name, old_upperdir, | |
849 | old->d_name.len); | |
850 | err = PTR_ERR(olddentry); | |
851 | if (IS_ERR(olddentry)) | |
852 | goto out_unlock; | |
853 | ||
854 | err = -ESTALE; | |
855 | if (olddentry != ovl_dentry_upper(old)) | |
856 | goto out_dput_old; | |
857 | ||
858 | newdentry = lookup_one_len(new->d_name.name, new_upperdir, | |
859 | new->d_name.len); | |
860 | err = PTR_ERR(newdentry); | |
861 | if (IS_ERR(newdentry)) | |
862 | goto out_dput_old; | |
863 | ||
864 | err = -ESTALE; | |
865 | if (ovl_dentry_upper(new)) { | |
e9be9d5e | 866 | if (opaquedir) { |
11f37104 MS |
867 | if (newdentry != opaquedir) |
868 | goto out_dput; | |
e9be9d5e | 869 | } else { |
11f37104 MS |
870 | if (newdentry != ovl_dentry_upper(new)) |
871 | goto out_dput; | |
e9be9d5e MS |
872 | } |
873 | } else { | |
11f37104 MS |
874 | if (!d_is_negative(newdentry) && |
875 | (!new_opaque || !ovl_is_whiteout(newdentry))) | |
876 | goto out_dput; | |
e9be9d5e MS |
877 | } |
878 | ||
e9be9d5e MS |
879 | if (olddentry == trap) |
880 | goto out_dput; | |
881 | if (newdentry == trap) | |
882 | goto out_dput; | |
883 | ||
884 | if (is_dir && !old_opaque && new_opaque) { | |
885 | err = ovl_set_opaque(olddentry); | |
886 | if (err) | |
887 | goto out_dput; | |
888 | } | |
889 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) { | |
890 | err = ovl_set_opaque(newdentry); | |
891 | if (err) | |
892 | goto out_dput; | |
893 | } | |
894 | ||
895 | if (old_opaque || new_opaque) { | |
896 | err = ovl_do_rename(old_upperdir->d_inode, olddentry, | |
897 | new_upperdir->d_inode, newdentry, | |
898 | flags); | |
899 | } else { | |
900 | /* No debug for the plain case */ | |
901 | BUG_ON(flags & ~RENAME_EXCHANGE); | |
902 | err = vfs_rename(old_upperdir->d_inode, olddentry, | |
903 | new_upperdir->d_inode, newdentry, | |
904 | NULL, flags); | |
905 | } | |
906 | ||
907 | if (err) { | |
908 | if (is_dir && !old_opaque && new_opaque) | |
909 | ovl_remove_opaque(olddentry); | |
910 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) | |
911 | ovl_remove_opaque(newdentry); | |
912 | goto out_dput; | |
913 | } | |
914 | ||
915 | if (is_dir && old_opaque && !new_opaque) | |
916 | ovl_remove_opaque(olddentry); | |
917 | if (!overwrite && new_is_dir && !old_opaque && new_opaque) | |
918 | ovl_remove_opaque(newdentry); | |
919 | ||
45d11738 KK |
920 | /* |
921 | * Old dentry now lives in different location. Dentries in | |
922 | * lowerstack are stale. We cannot drop them here because | |
923 | * access to them is lockless. This could be only pure upper | |
924 | * or opaque directory - numlower is zero. Or upper non-dir | |
925 | * entry - its pureness is tracked by flag opaque. | |
926 | */ | |
e9be9d5e MS |
927 | if (old_opaque != new_opaque) { |
928 | ovl_dentry_set_opaque(old, new_opaque); | |
929 | if (!overwrite) | |
930 | ovl_dentry_set_opaque(new, old_opaque); | |
931 | } | |
932 | ||
933 | if (cleanup_whiteout) | |
934 | ovl_cleanup(old_upperdir->d_inode, newdentry); | |
935 | ||
936 | ovl_dentry_version_inc(old->d_parent); | |
937 | ovl_dentry_version_inc(new->d_parent); | |
938 | ||
939 | out_dput: | |
940 | dput(newdentry); | |
11f37104 MS |
941 | out_dput_old: |
942 | dput(olddentry); | |
e9be9d5e MS |
943 | out_unlock: |
944 | unlock_rename(new_upperdir, old_upperdir); | |
945 | out_revert_creds: | |
946 | if (old_opaque || new_opaque) { | |
947 | revert_creds(old_cred); | |
948 | put_cred(override_cred); | |
949 | } | |
950 | out_drop_write: | |
951 | ovl_drop_write(old); | |
952 | out: | |
953 | dput(opaquedir); | |
954 | return err; | |
955 | } | |
956 | ||
957 | const struct inode_operations ovl_dir_inode_operations = { | |
958 | .lookup = ovl_lookup, | |
959 | .mkdir = ovl_mkdir, | |
960 | .symlink = ovl_symlink, | |
961 | .unlink = ovl_unlink, | |
962 | .rmdir = ovl_rmdir, | |
963 | .rename2 = ovl_rename2, | |
964 | .link = ovl_link, | |
965 | .setattr = ovl_setattr, | |
966 | .create = ovl_create, | |
967 | .mknod = ovl_mknod, | |
968 | .permission = ovl_permission, | |
969 | .getattr = ovl_dir_getattr, | |
970 | .setxattr = ovl_setxattr, | |
971 | .getxattr = ovl_getxattr, | |
972 | .listxattr = ovl_listxattr, | |
973 | .removexattr = ovl_removexattr, | |
974 | }; |