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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 | ||
72e48481 VG |
161 | /* Common operations required to be done after creation of file on upper */ |
162 | static void ovl_instantiate(struct dentry *dentry, struct inode *inode, | |
163 | struct dentry *newdentry) | |
164 | { | |
165 | ovl_dentry_version_inc(dentry->d_parent); | |
166 | ovl_dentry_update(dentry, newdentry); | |
167 | ovl_copyattr(newdentry->d_inode, inode); | |
168 | d_instantiate(dentry, inode); | |
169 | } | |
170 | ||
e9be9d5e MS |
171 | static int ovl_create_upper(struct dentry *dentry, struct inode *inode, |
172 | struct kstat *stat, const char *link, | |
173 | struct dentry *hardlink) | |
174 | { | |
175 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
176 | struct inode *udir = upperdir->d_inode; | |
177 | struct dentry *newdentry; | |
178 | int err; | |
179 | ||
5955102c | 180 | inode_lock_nested(udir, I_MUTEX_PARENT); |
e9be9d5e MS |
181 | newdentry = lookup_one_len(dentry->d_name.name, upperdir, |
182 | dentry->d_name.len); | |
183 | err = PTR_ERR(newdentry); | |
184 | if (IS_ERR(newdentry)) | |
185 | goto out_unlock; | |
186 | err = ovl_create_real(udir, newdentry, stat, link, hardlink, false); | |
187 | if (err) | |
188 | goto out_dput; | |
189 | ||
72e48481 | 190 | ovl_instantiate(dentry, inode, newdentry); |
e9be9d5e MS |
191 | newdentry = NULL; |
192 | out_dput: | |
193 | dput(newdentry); | |
194 | out_unlock: | |
5955102c | 195 | inode_unlock(udir); |
e9be9d5e MS |
196 | return err; |
197 | } | |
198 | ||
199 | static int ovl_lock_rename_workdir(struct dentry *workdir, | |
200 | struct dentry *upperdir) | |
201 | { | |
202 | /* Workdir should not be the same as upperdir */ | |
203 | if (workdir == upperdir) | |
204 | goto err; | |
205 | ||
206 | /* Workdir should not be subdir of upperdir and vice versa */ | |
207 | if (lock_rename(workdir, upperdir) != NULL) | |
208 | goto err_unlock; | |
209 | ||
210 | return 0; | |
211 | ||
212 | err_unlock: | |
213 | unlock_rename(workdir, upperdir); | |
214 | err: | |
215 | pr_err("overlayfs: failed to lock workdir+upperdir\n"); | |
216 | return -EIO; | |
217 | } | |
218 | ||
219 | static struct dentry *ovl_clear_empty(struct dentry *dentry, | |
220 | struct list_head *list) | |
221 | { | |
222 | struct dentry *workdir = ovl_workdir(dentry); | |
223 | struct inode *wdir = workdir->d_inode; | |
224 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
225 | struct inode *udir = upperdir->d_inode; | |
226 | struct path upperpath; | |
227 | struct dentry *upper; | |
228 | struct dentry *opaquedir; | |
229 | struct kstat stat; | |
230 | int err; | |
231 | ||
cc6f67bc MS |
232 | if (WARN_ON(!workdir)) |
233 | return ERR_PTR(-EROFS); | |
234 | ||
e9be9d5e MS |
235 | err = ovl_lock_rename_workdir(workdir, upperdir); |
236 | if (err) | |
237 | goto out; | |
238 | ||
239 | ovl_path_upper(dentry, &upperpath); | |
240 | err = vfs_getattr(&upperpath, &stat); | |
241 | if (err) | |
242 | goto out_unlock; | |
243 | ||
244 | err = -ESTALE; | |
245 | if (!S_ISDIR(stat.mode)) | |
246 | goto out_unlock; | |
247 | upper = upperpath.dentry; | |
248 | if (upper->d_parent->d_inode != udir) | |
249 | goto out_unlock; | |
250 | ||
251 | opaquedir = ovl_lookup_temp(workdir, dentry); | |
252 | err = PTR_ERR(opaquedir); | |
253 | if (IS_ERR(opaquedir)) | |
254 | goto out_unlock; | |
255 | ||
256 | err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true); | |
257 | if (err) | |
258 | goto out_dput; | |
259 | ||
260 | err = ovl_copy_xattr(upper, opaquedir); | |
261 | if (err) | |
262 | goto out_cleanup; | |
263 | ||
264 | err = ovl_set_opaque(opaquedir); | |
265 | if (err) | |
266 | goto out_cleanup; | |
267 | ||
5955102c | 268 | inode_lock(opaquedir->d_inode); |
e9be9d5e | 269 | err = ovl_set_attr(opaquedir, &stat); |
5955102c | 270 | inode_unlock(opaquedir->d_inode); |
e9be9d5e MS |
271 | if (err) |
272 | goto out_cleanup; | |
273 | ||
274 | err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE); | |
275 | if (err) | |
276 | goto out_cleanup; | |
277 | ||
278 | ovl_cleanup_whiteouts(upper, list); | |
279 | ovl_cleanup(wdir, upper); | |
280 | unlock_rename(workdir, upperdir); | |
281 | ||
282 | /* dentry's upper doesn't match now, get rid of it */ | |
283 | d_drop(dentry); | |
284 | ||
285 | return opaquedir; | |
286 | ||
287 | out_cleanup: | |
288 | ovl_cleanup(wdir, opaquedir); | |
289 | out_dput: | |
290 | dput(opaquedir); | |
291 | out_unlock: | |
292 | unlock_rename(workdir, upperdir); | |
293 | out: | |
294 | return ERR_PTR(err); | |
295 | } | |
296 | ||
a105d685 | 297 | static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry) |
e9be9d5e MS |
298 | { |
299 | int err; | |
300 | struct dentry *ret = NULL; | |
301 | LIST_HEAD(list); | |
302 | ||
303 | err = ovl_check_empty_dir(dentry, &list); | |
304 | if (err) | |
305 | ret = ERR_PTR(err); | |
a105d685 MS |
306 | else { |
307 | /* | |
308 | * If no upperdentry then skip clearing whiteouts. | |
309 | * | |
310 | * Can race with copy-up, since we don't hold the upperdir | |
311 | * mutex. Doesn't matter, since copy-up can't create a | |
312 | * non-empty directory from an empty one. | |
313 | */ | |
314 | if (ovl_dentry_upper(dentry)) | |
315 | ret = ovl_clear_empty(dentry, &list); | |
316 | } | |
e9be9d5e MS |
317 | |
318 | ovl_cache_free(&list); | |
319 | ||
320 | return ret; | |
321 | } | |
322 | ||
323 | static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, | |
324 | struct kstat *stat, const char *link, | |
325 | struct dentry *hardlink) | |
326 | { | |
327 | struct dentry *workdir = ovl_workdir(dentry); | |
328 | struct inode *wdir = workdir->d_inode; | |
329 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
330 | struct inode *udir = upperdir->d_inode; | |
331 | struct dentry *upper; | |
332 | struct dentry *newdentry; | |
333 | int err; | |
334 | ||
cc6f67bc MS |
335 | if (WARN_ON(!workdir)) |
336 | return -EROFS; | |
337 | ||
e9be9d5e MS |
338 | err = ovl_lock_rename_workdir(workdir, upperdir); |
339 | if (err) | |
340 | goto out; | |
341 | ||
342 | newdentry = ovl_lookup_temp(workdir, dentry); | |
343 | err = PTR_ERR(newdentry); | |
344 | if (IS_ERR(newdentry)) | |
345 | goto out_unlock; | |
346 | ||
347 | upper = lookup_one_len(dentry->d_name.name, upperdir, | |
348 | dentry->d_name.len); | |
349 | err = PTR_ERR(upper); | |
350 | if (IS_ERR(upper)) | |
351 | goto out_dput; | |
352 | ||
353 | err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true); | |
354 | if (err) | |
355 | goto out_dput2; | |
356 | ||
357 | if (S_ISDIR(stat->mode)) { | |
358 | err = ovl_set_opaque(newdentry); | |
359 | if (err) | |
360 | goto out_cleanup; | |
361 | ||
362 | err = ovl_do_rename(wdir, newdentry, udir, upper, | |
363 | RENAME_EXCHANGE); | |
364 | if (err) | |
365 | goto out_cleanup; | |
366 | ||
367 | ovl_cleanup(wdir, upper); | |
368 | } else { | |
369 | err = ovl_do_rename(wdir, newdentry, udir, upper, 0); | |
370 | if (err) | |
371 | goto out_cleanup; | |
372 | } | |
72e48481 | 373 | ovl_instantiate(dentry, inode, newdentry); |
e9be9d5e MS |
374 | newdentry = NULL; |
375 | out_dput2: | |
376 | dput(upper); | |
377 | out_dput: | |
378 | dput(newdentry); | |
379 | out_unlock: | |
380 | unlock_rename(workdir, upperdir); | |
381 | out: | |
382 | return err; | |
383 | ||
384 | out_cleanup: | |
385 | ovl_cleanup(wdir, newdentry); | |
386 | goto out_dput2; | |
387 | } | |
388 | ||
389 | static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev, | |
390 | const char *link, struct dentry *hardlink) | |
391 | { | |
392 | int err; | |
393 | struct inode *inode; | |
394 | struct kstat stat = { | |
395 | .mode = mode, | |
396 | .rdev = rdev, | |
397 | }; | |
398 | ||
399 | err = -ENOMEM; | |
400 | inode = ovl_new_inode(dentry->d_sb, mode, dentry->d_fsdata); | |
401 | if (!inode) | |
402 | goto out; | |
403 | ||
404 | err = ovl_copy_up(dentry->d_parent); | |
405 | if (err) | |
406 | goto out_iput; | |
407 | ||
408 | if (!ovl_dentry_is_opaque(dentry)) { | |
409 | err = ovl_create_upper(dentry, inode, &stat, link, hardlink); | |
410 | } else { | |
411 | const struct cred *old_cred; | |
d0e13f5b | 412 | struct cred *override_cred; |
e9be9d5e | 413 | |
3fe6e52f | 414 | old_cred = ovl_override_creds(dentry->d_sb); |
e9be9d5e | 415 | |
d0e13f5b MS |
416 | err = -ENOMEM; |
417 | override_cred = prepare_creds(); | |
418 | if (override_cred) { | |
419 | override_cred->fsuid = old_cred->fsuid; | |
420 | override_cred->fsgid = old_cred->fsgid; | |
421 | put_cred(override_creds(override_cred)); | |
422 | put_cred(override_cred); | |
e9be9d5e | 423 | |
d0e13f5b MS |
424 | err = ovl_create_over_whiteout(dentry, inode, &stat, |
425 | link, hardlink); | |
426 | } | |
e9be9d5e | 427 | revert_creds(old_cred); |
e9be9d5e MS |
428 | } |
429 | ||
430 | if (!err) | |
431 | inode = NULL; | |
432 | out_iput: | |
433 | iput(inode); | |
434 | out: | |
435 | return err; | |
436 | } | |
437 | ||
438 | static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, | |
439 | const char *link) | |
440 | { | |
441 | int err; | |
442 | ||
443 | err = ovl_want_write(dentry); | |
444 | if (!err) { | |
445 | err = ovl_create_or_link(dentry, mode, rdev, link, NULL); | |
446 | ovl_drop_write(dentry); | |
447 | } | |
448 | ||
449 | return err; | |
450 | } | |
451 | ||
452 | static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode, | |
453 | bool excl) | |
454 | { | |
455 | return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL); | |
456 | } | |
457 | ||
458 | static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) | |
459 | { | |
460 | return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL); | |
461 | } | |
462 | ||
463 | static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, | |
464 | dev_t rdev) | |
465 | { | |
466 | /* Don't allow creation of "whiteout" on overlay */ | |
467 | if (S_ISCHR(mode) && rdev == WHITEOUT_DEV) | |
468 | return -EPERM; | |
469 | ||
470 | return ovl_create_object(dentry, mode, rdev, NULL); | |
471 | } | |
472 | ||
473 | static int ovl_symlink(struct inode *dir, struct dentry *dentry, | |
474 | const char *link) | |
475 | { | |
476 | return ovl_create_object(dentry, S_IFLNK, 0, link); | |
477 | } | |
478 | ||
479 | static int ovl_link(struct dentry *old, struct inode *newdir, | |
480 | struct dentry *new) | |
481 | { | |
482 | int err; | |
483 | struct dentry *upper; | |
484 | ||
485 | err = ovl_want_write(old); | |
486 | if (err) | |
487 | goto out; | |
488 | ||
489 | err = ovl_copy_up(old); | |
490 | if (err) | |
491 | goto out_drop_write; | |
492 | ||
493 | upper = ovl_dentry_upper(old); | |
494 | err = ovl_create_or_link(new, upper->d_inode->i_mode, 0, NULL, upper); | |
495 | ||
496 | out_drop_write: | |
497 | ovl_drop_write(old); | |
498 | out: | |
499 | return err; | |
500 | } | |
501 | ||
a105d685 | 502 | static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir) |
e9be9d5e MS |
503 | { |
504 | struct dentry *workdir = ovl_workdir(dentry); | |
505 | struct inode *wdir = workdir->d_inode; | |
506 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
507 | struct inode *udir = upperdir->d_inode; | |
508 | struct dentry *whiteout; | |
509 | struct dentry *upper; | |
510 | struct dentry *opaquedir = NULL; | |
511 | int err; | |
cfc9fde0 | 512 | int flags = 0; |
e9be9d5e | 513 | |
cc6f67bc MS |
514 | if (WARN_ON(!workdir)) |
515 | return -EROFS; | |
516 | ||
d377c5eb MS |
517 | if (is_dir) { |
518 | if (OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) { | |
519 | opaquedir = ovl_check_empty_and_clear(dentry); | |
520 | err = PTR_ERR(opaquedir); | |
521 | if (IS_ERR(opaquedir)) | |
522 | goto out; | |
523 | } else { | |
524 | LIST_HEAD(list); | |
525 | ||
526 | /* | |
527 | * When removing an empty opaque directory, then it | |
528 | * makes no sense to replace it with an exact replica of | |
529 | * itself. But emptiness still needs to be checked. | |
530 | */ | |
531 | err = ovl_check_empty_dir(dentry, &list); | |
532 | ovl_cache_free(&list); | |
533 | if (err) | |
534 | goto out; | |
535 | } | |
e9be9d5e MS |
536 | } |
537 | ||
538 | err = ovl_lock_rename_workdir(workdir, upperdir); | |
539 | if (err) | |
540 | goto out_dput; | |
541 | ||
cfc9fde0 MP |
542 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
543 | dentry->d_name.len); | |
544 | err = PTR_ERR(upper); | |
545 | if (IS_ERR(upper)) | |
e9be9d5e MS |
546 | goto out_unlock; |
547 | ||
cfc9fde0 MP |
548 | err = -ESTALE; |
549 | if ((opaquedir && upper != opaquedir) || | |
550 | (!opaquedir && ovl_dentry_upper(dentry) && | |
551 | upper != ovl_dentry_upper(dentry))) { | |
552 | goto out_dput_upper; | |
553 | } | |
e9be9d5e | 554 | |
cfc9fde0 MP |
555 | whiteout = ovl_whiteout(workdir, dentry); |
556 | err = PTR_ERR(whiteout); | |
557 | if (IS_ERR(whiteout)) | |
558 | goto out_dput_upper; | |
e9be9d5e | 559 | |
cfc9fde0 MP |
560 | if (d_is_dir(upper)) |
561 | flags = RENAME_EXCHANGE; | |
e9be9d5e | 562 | |
cfc9fde0 MP |
563 | err = ovl_do_rename(wdir, whiteout, udir, upper, flags); |
564 | if (err) | |
565 | goto kill_whiteout; | |
566 | if (flags) | |
567 | ovl_cleanup(wdir, upper); | |
e9be9d5e | 568 | |
e9be9d5e MS |
569 | ovl_dentry_version_inc(dentry->d_parent); |
570 | out_d_drop: | |
571 | d_drop(dentry); | |
572 | dput(whiteout); | |
cfc9fde0 MP |
573 | out_dput_upper: |
574 | dput(upper); | |
e9be9d5e MS |
575 | out_unlock: |
576 | unlock_rename(workdir, upperdir); | |
577 | out_dput: | |
578 | dput(opaquedir); | |
579 | out: | |
580 | return err; | |
581 | ||
582 | kill_whiteout: | |
583 | ovl_cleanup(wdir, whiteout); | |
584 | goto out_d_drop; | |
585 | } | |
586 | ||
587 | static int ovl_remove_upper(struct dentry *dentry, bool is_dir) | |
588 | { | |
589 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
590 | struct inode *dir = upperdir->d_inode; | |
11f37104 | 591 | struct dentry *upper; |
e9be9d5e MS |
592 | int err; |
593 | ||
5955102c | 594 | inode_lock_nested(dir, I_MUTEX_PARENT); |
11f37104 MS |
595 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
596 | dentry->d_name.len); | |
597 | err = PTR_ERR(upper); | |
598 | if (IS_ERR(upper)) | |
599 | goto out_unlock; | |
600 | ||
e9be9d5e | 601 | err = -ESTALE; |
11f37104 | 602 | if (upper == ovl_dentry_upper(dentry)) { |
e9be9d5e MS |
603 | if (is_dir) |
604 | err = vfs_rmdir(dir, upper); | |
605 | else | |
606 | err = vfs_unlink(dir, upper, NULL); | |
e9be9d5e MS |
607 | ovl_dentry_version_inc(dentry->d_parent); |
608 | } | |
11f37104 | 609 | dput(upper); |
e9be9d5e MS |
610 | |
611 | /* | |
612 | * Keeping this dentry hashed would mean having to release | |
613 | * upperpath/lowerpath, which could only be done if we are the | |
614 | * sole user of this dentry. Too tricky... Just unhash for | |
615 | * now. | |
616 | */ | |
ce9113bb RW |
617 | if (!err) |
618 | d_drop(dentry); | |
11f37104 | 619 | out_unlock: |
5955102c | 620 | inode_unlock(dir); |
e9be9d5e MS |
621 | |
622 | return err; | |
623 | } | |
624 | ||
625 | static inline int ovl_check_sticky(struct dentry *dentry) | |
626 | { | |
627 | struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode; | |
628 | struct inode *inode = ovl_dentry_real(dentry)->d_inode; | |
629 | ||
630 | if (check_sticky(dir, inode)) | |
631 | return -EPERM; | |
632 | ||
633 | return 0; | |
634 | } | |
635 | ||
636 | static int ovl_do_remove(struct dentry *dentry, bool is_dir) | |
637 | { | |
638 | enum ovl_path_type type; | |
639 | int err; | |
640 | ||
641 | err = ovl_check_sticky(dentry); | |
642 | if (err) | |
643 | goto out; | |
644 | ||
645 | err = ovl_want_write(dentry); | |
646 | if (err) | |
647 | goto out; | |
648 | ||
649 | err = ovl_copy_up(dentry->d_parent); | |
650 | if (err) | |
651 | goto out_drop_write; | |
652 | ||
653 | type = ovl_path_type(dentry); | |
1afaba1e | 654 | if (OVL_TYPE_PURE_UPPER(type)) { |
e9be9d5e MS |
655 | err = ovl_remove_upper(dentry, is_dir); |
656 | } else { | |
3fe6e52f | 657 | const struct cred *old_cred = ovl_override_creds(dentry->d_sb); |
e9be9d5e | 658 | |
a105d685 | 659 | err = ovl_remove_and_whiteout(dentry, is_dir); |
e9be9d5e MS |
660 | |
661 | revert_creds(old_cred); | |
e9be9d5e MS |
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; | |
e9be9d5e MS |
693 | bool cleanup_whiteout = false; |
694 | bool overwrite = !(flags & RENAME_EXCHANGE); | |
e36cb0b8 | 695 | bool is_dir = d_is_dir(old); |
e9be9d5e MS |
696 | bool new_is_dir = false; |
697 | struct dentry *opaquedir = NULL; | |
698 | const struct cred *old_cred = NULL; | |
e9be9d5e MS |
699 | |
700 | err = -EINVAL; | |
701 | if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) | |
702 | goto out; | |
703 | ||
704 | flags &= ~RENAME_NOREPLACE; | |
705 | ||
706 | err = ovl_check_sticky(old); | |
707 | if (err) | |
708 | goto out; | |
709 | ||
710 | /* Don't copy up directory trees */ | |
711 | old_type = ovl_path_type(old); | |
712 | err = -EXDEV; | |
1afaba1e | 713 | if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir) |
e9be9d5e MS |
714 | goto out; |
715 | ||
716 | if (new->d_inode) { | |
717 | err = ovl_check_sticky(new); | |
718 | if (err) | |
719 | goto out; | |
720 | ||
e36cb0b8 | 721 | if (d_is_dir(new)) |
e9be9d5e MS |
722 | new_is_dir = true; |
723 | ||
724 | new_type = ovl_path_type(new); | |
725 | err = -EXDEV; | |
1afaba1e | 726 | if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) |
e9be9d5e MS |
727 | goto out; |
728 | ||
729 | err = 0; | |
1afaba1e | 730 | if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) { |
e9be9d5e MS |
731 | if (ovl_dentry_lower(old)->d_inode == |
732 | ovl_dentry_lower(new)->d_inode) | |
733 | goto out; | |
734 | } | |
1afaba1e | 735 | if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) { |
e9be9d5e MS |
736 | if (ovl_dentry_upper(old)->d_inode == |
737 | ovl_dentry_upper(new)->d_inode) | |
738 | goto out; | |
739 | } | |
740 | } else { | |
741 | if (ovl_dentry_is_opaque(new)) | |
1afaba1e | 742 | new_type = __OVL_PATH_UPPER; |
e9be9d5e | 743 | else |
1afaba1e | 744 | new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE; |
e9be9d5e MS |
745 | } |
746 | ||
747 | err = ovl_want_write(old); | |
748 | if (err) | |
749 | goto out; | |
750 | ||
751 | err = ovl_copy_up(old); | |
752 | if (err) | |
753 | goto out_drop_write; | |
754 | ||
755 | err = ovl_copy_up(new->d_parent); | |
756 | if (err) | |
757 | goto out_drop_write; | |
758 | if (!overwrite) { | |
759 | err = ovl_copy_up(new); | |
760 | if (err) | |
761 | goto out_drop_write; | |
762 | } | |
763 | ||
1afaba1e MS |
764 | old_opaque = !OVL_TYPE_PURE_UPPER(old_type); |
765 | new_opaque = !OVL_TYPE_PURE_UPPER(new_type); | |
e9be9d5e | 766 | |
3fe6e52f AM |
767 | if (old_opaque || new_opaque) |
768 | old_cred = ovl_override_creds(old->d_sb); | |
e9be9d5e | 769 | |
1afaba1e | 770 | if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) { |
a105d685 | 771 | opaquedir = ovl_check_empty_and_clear(new); |
e9be9d5e MS |
772 | err = PTR_ERR(opaquedir); |
773 | if (IS_ERR(opaquedir)) { | |
774 | opaquedir = NULL; | |
775 | goto out_revert_creds; | |
776 | } | |
777 | } | |
778 | ||
779 | if (overwrite) { | |
780 | if (old_opaque) { | |
781 | if (new->d_inode || !new_opaque) { | |
782 | /* Whiteout source */ | |
783 | flags |= RENAME_WHITEOUT; | |
784 | } else { | |
785 | /* Switch whiteouts */ | |
786 | flags |= RENAME_EXCHANGE; | |
787 | } | |
788 | } else if (is_dir && !new->d_inode && new_opaque) { | |
789 | flags |= RENAME_EXCHANGE; | |
790 | cleanup_whiteout = true; | |
791 | } | |
792 | } | |
793 | ||
794 | old_upperdir = ovl_dentry_upper(old->d_parent); | |
795 | new_upperdir = ovl_dentry_upper(new->d_parent); | |
796 | ||
797 | trap = lock_rename(new_upperdir, old_upperdir); | |
798 | ||
11f37104 MS |
799 | |
800 | olddentry = lookup_one_len(old->d_name.name, old_upperdir, | |
801 | old->d_name.len); | |
802 | err = PTR_ERR(olddentry); | |
803 | if (IS_ERR(olddentry)) | |
804 | goto out_unlock; | |
805 | ||
806 | err = -ESTALE; | |
807 | if (olddentry != ovl_dentry_upper(old)) | |
808 | goto out_dput_old; | |
809 | ||
810 | newdentry = lookup_one_len(new->d_name.name, new_upperdir, | |
811 | new->d_name.len); | |
812 | err = PTR_ERR(newdentry); | |
813 | if (IS_ERR(newdentry)) | |
814 | goto out_dput_old; | |
815 | ||
816 | err = -ESTALE; | |
817 | if (ovl_dentry_upper(new)) { | |
e9be9d5e | 818 | if (opaquedir) { |
11f37104 MS |
819 | if (newdentry != opaquedir) |
820 | goto out_dput; | |
e9be9d5e | 821 | } else { |
11f37104 MS |
822 | if (newdentry != ovl_dentry_upper(new)) |
823 | goto out_dput; | |
e9be9d5e MS |
824 | } |
825 | } else { | |
11f37104 MS |
826 | if (!d_is_negative(newdentry) && |
827 | (!new_opaque || !ovl_is_whiteout(newdentry))) | |
828 | goto out_dput; | |
e9be9d5e MS |
829 | } |
830 | ||
e9be9d5e MS |
831 | if (olddentry == trap) |
832 | goto out_dput; | |
833 | if (newdentry == trap) | |
834 | goto out_dput; | |
835 | ||
836 | if (is_dir && !old_opaque && new_opaque) { | |
837 | err = ovl_set_opaque(olddentry); | |
838 | if (err) | |
839 | goto out_dput; | |
840 | } | |
841 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) { | |
842 | err = ovl_set_opaque(newdentry); | |
843 | if (err) | |
844 | goto out_dput; | |
845 | } | |
846 | ||
847 | if (old_opaque || new_opaque) { | |
848 | err = ovl_do_rename(old_upperdir->d_inode, olddentry, | |
849 | new_upperdir->d_inode, newdentry, | |
850 | flags); | |
851 | } else { | |
852 | /* No debug for the plain case */ | |
853 | BUG_ON(flags & ~RENAME_EXCHANGE); | |
854 | err = vfs_rename(old_upperdir->d_inode, olddentry, | |
855 | new_upperdir->d_inode, newdentry, | |
856 | NULL, flags); | |
857 | } | |
858 | ||
859 | if (err) { | |
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 | goto out_dput; | |
865 | } | |
866 | ||
867 | if (is_dir && old_opaque && !new_opaque) | |
868 | ovl_remove_opaque(olddentry); | |
869 | if (!overwrite && new_is_dir && !old_opaque && new_opaque) | |
870 | ovl_remove_opaque(newdentry); | |
871 | ||
45d11738 KK |
872 | /* |
873 | * Old dentry now lives in different location. Dentries in | |
874 | * lowerstack are stale. We cannot drop them here because | |
875 | * access to them is lockless. This could be only pure upper | |
876 | * or opaque directory - numlower is zero. Or upper non-dir | |
877 | * entry - its pureness is tracked by flag opaque. | |
878 | */ | |
e9be9d5e MS |
879 | if (old_opaque != new_opaque) { |
880 | ovl_dentry_set_opaque(old, new_opaque); | |
881 | if (!overwrite) | |
882 | ovl_dentry_set_opaque(new, old_opaque); | |
883 | } | |
884 | ||
885 | if (cleanup_whiteout) | |
886 | ovl_cleanup(old_upperdir->d_inode, newdentry); | |
887 | ||
888 | ovl_dentry_version_inc(old->d_parent); | |
889 | ovl_dentry_version_inc(new->d_parent); | |
890 | ||
891 | out_dput: | |
892 | dput(newdentry); | |
11f37104 MS |
893 | out_dput_old: |
894 | dput(olddentry); | |
e9be9d5e MS |
895 | out_unlock: |
896 | unlock_rename(new_upperdir, old_upperdir); | |
897 | out_revert_creds: | |
3fe6e52f | 898 | if (old_opaque || new_opaque) |
e9be9d5e | 899 | revert_creds(old_cred); |
e9be9d5e MS |
900 | out_drop_write: |
901 | ovl_drop_write(old); | |
902 | out: | |
903 | dput(opaquedir); | |
904 | return err; | |
905 | } | |
906 | ||
907 | const struct inode_operations ovl_dir_inode_operations = { | |
908 | .lookup = ovl_lookup, | |
909 | .mkdir = ovl_mkdir, | |
910 | .symlink = ovl_symlink, | |
911 | .unlink = ovl_unlink, | |
912 | .rmdir = ovl_rmdir, | |
913 | .rename2 = ovl_rename2, | |
914 | .link = ovl_link, | |
915 | .setattr = ovl_setattr, | |
916 | .create = ovl_create, | |
917 | .mknod = ovl_mknod, | |
918 | .permission = ovl_permission, | |
919 | .getattr = ovl_dir_getattr, | |
920 | .setxattr = ovl_setxattr, | |
921 | .getxattr = ovl_getxattr, | |
922 | .listxattr = ovl_listxattr, | |
923 | .removexattr = ovl_removexattr, | |
924 | }; |