aboutsummaryrefslogtreecommitdiffstats
path: root/fs/overlayfs/dir.c
diff options
context:
space:
mode:
Diffstat (limited to 'fs/overlayfs/dir.c')
-rw-r--r--fs/overlayfs/dir.c921
1 files changed, 921 insertions, 0 deletions
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
new file mode 100644
index 000000000000..15cd91ad9940
--- /dev/null
+++ b/fs/overlayfs/dir.c
@@ -0,0 +1,921 @@
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
17void 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
34struct 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 */
52static 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
72int 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
119static int ovl_set_opaque(struct dentry *upperdentry)
120{
121 return ovl_do_setxattr(upperdentry, ovl_opaque_xattr, "y", 1, 0);
122}
123
124static void ovl_remove_opaque(struct dentry *upperdentry)
125{
126 int err;
127
128 err = ovl_do_removexattr(upperdentry, ovl_opaque_xattr);
129 if (err) {
130 pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n",
131 upperdentry->d_name.name, err);
132 }
133}
134
135static 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 */
155 if (type == OVL_PATH_MERGE)
156 stat->nlink = 1;
157
158 return 0;
159}
160
161static 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;
185out_dput:
186 dput(newdentry);
187out_unlock:
188 mutex_unlock(&udir->i_mutex);
189 return err;
190}
191
192static 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
205err_unlock:
206 unlock_rename(workdir, upperdir);
207err:
208 pr_err("overlayfs: failed to lock workdir+upperdir\n");
209 return -EIO;
210}
211
212static 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
277out_cleanup:
278 ovl_cleanup(wdir, opaquedir);
279out_dput:
280 dput(opaquedir);
281out_unlock:
282 unlock_rename(workdir, upperdir);
283out:
284 return ERR_PTR(err);
285}
286
287static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry,
288 enum ovl_path_type type)
289{
290 int err;
291 struct dentry *ret = NULL;
292 LIST_HEAD(list);
293
294 err = ovl_check_empty_dir(dentry, &list);
295 if (err)
296 ret = ERR_PTR(err);
297 else if (type == OVL_PATH_MERGE)
298 ret = ovl_clear_empty(dentry, &list);
299
300 ovl_cache_free(&list);
301
302 return ret;
303}
304
305static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
306 struct kstat *stat, const char *link,
307 struct dentry *hardlink)
308{
309 struct dentry *workdir = ovl_workdir(dentry);
310 struct inode *wdir = workdir->d_inode;
311 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
312 struct inode *udir = upperdir->d_inode;
313 struct dentry *upper;
314 struct dentry *newdentry;
315 int err;
316
317 err = ovl_lock_rename_workdir(workdir, upperdir);
318 if (err)
319 goto out;
320
321 newdentry = ovl_lookup_temp(workdir, dentry);
322 err = PTR_ERR(newdentry);
323 if (IS_ERR(newdentry))
324 goto out_unlock;
325
326 upper = lookup_one_len(dentry->d_name.name, upperdir,
327 dentry->d_name.len);
328 err = PTR_ERR(upper);
329 if (IS_ERR(upper))
330 goto out_dput;
331
332 err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true);
333 if (err)
334 goto out_dput2;
335
336 if (S_ISDIR(stat->mode)) {
337 err = ovl_set_opaque(newdentry);
338 if (err)
339 goto out_cleanup;
340
341 err = ovl_do_rename(wdir, newdentry, udir, upper,
342 RENAME_EXCHANGE);
343 if (err)
344 goto out_cleanup;
345
346 ovl_cleanup(wdir, upper);
347 } else {
348 err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
349 if (err)
350 goto out_cleanup;
351 }
352 ovl_dentry_version_inc(dentry->d_parent);
353 ovl_dentry_update(dentry, newdentry);
354 ovl_copyattr(newdentry->d_inode, inode);
355 d_instantiate(dentry, inode);
356 newdentry = NULL;
357out_dput2:
358 dput(upper);
359out_dput:
360 dput(newdentry);
361out_unlock:
362 unlock_rename(workdir, upperdir);
363out:
364 return err;
365
366out_cleanup:
367 ovl_cleanup(wdir, newdentry);
368 goto out_dput2;
369}
370
371static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev,
372 const char *link, struct dentry *hardlink)
373{
374 int err;
375 struct inode *inode;
376 struct kstat stat = {
377 .mode = mode,
378 .rdev = rdev,
379 };
380
381 err = -ENOMEM;
382 inode = ovl_new_inode(dentry->d_sb, mode, dentry->d_fsdata);
383 if (!inode)
384 goto out;
385
386 err = ovl_copy_up(dentry->d_parent);
387 if (err)
388 goto out_iput;
389
390 if (!ovl_dentry_is_opaque(dentry)) {
391 err = ovl_create_upper(dentry, inode, &stat, link, hardlink);
392 } else {
393 const struct cred *old_cred;
394 struct cred *override_cred;
395
396 err = -ENOMEM;
397 override_cred = prepare_creds();
398 if (!override_cred)
399 goto out_iput;
400
401 /*
402 * CAP_SYS_ADMIN for setting opaque xattr
403 * CAP_DAC_OVERRIDE for create in workdir, rename
404 * CAP_FOWNER for removing whiteout from sticky dir
405 */
406 cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
407 cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
408 cap_raise(override_cred->cap_effective, CAP_FOWNER);
409 old_cred = override_creds(override_cred);
410
411 err = ovl_create_over_whiteout(dentry, inode, &stat, link,
412 hardlink);
413
414 revert_creds(old_cred);
415 put_cred(override_cred);
416 }
417
418 if (!err)
419 inode = NULL;
420out_iput:
421 iput(inode);
422out:
423 return err;
424}
425
426static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
427 const char *link)
428{
429 int err;
430
431 err = ovl_want_write(dentry);
432 if (!err) {
433 err = ovl_create_or_link(dentry, mode, rdev, link, NULL);
434 ovl_drop_write(dentry);
435 }
436
437 return err;
438}
439
440static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode,
441 bool excl)
442{
443 return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
444}
445
446static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
447{
448 return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL);
449}
450
451static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
452 dev_t rdev)
453{
454 /* Don't allow creation of "whiteout" on overlay */
455 if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
456 return -EPERM;
457
458 return ovl_create_object(dentry, mode, rdev, NULL);
459}
460
461static int ovl_symlink(struct inode *dir, struct dentry *dentry,
462 const char *link)
463{
464 return ovl_create_object(dentry, S_IFLNK, 0, link);
465}
466
467static int ovl_link(struct dentry *old, struct inode *newdir,
468 struct dentry *new)
469{
470 int err;
471 struct dentry *upper;
472
473 err = ovl_want_write(old);
474 if (err)
475 goto out;
476
477 err = ovl_copy_up(old);
478 if (err)
479 goto out_drop_write;
480
481 upper = ovl_dentry_upper(old);
482 err = ovl_create_or_link(new, upper->d_inode->i_mode, 0, NULL, upper);
483
484out_drop_write:
485 ovl_drop_write(old);
486out:
487 return err;
488}
489
490static int ovl_remove_and_whiteout(struct dentry *dentry,
491 enum ovl_path_type type, bool is_dir)
492{
493 struct dentry *workdir = ovl_workdir(dentry);
494 struct inode *wdir = workdir->d_inode;
495 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
496 struct inode *udir = upperdir->d_inode;
497 struct dentry *whiteout;
498 struct dentry *upper;
499 struct dentry *opaquedir = NULL;
500 int err;
501
502 if (is_dir) {
503 opaquedir = ovl_check_empty_and_clear(dentry, type);
504 err = PTR_ERR(opaquedir);
505 if (IS_ERR(opaquedir))
506 goto out;
507 }
508
509 err = ovl_lock_rename_workdir(workdir, upperdir);
510 if (err)
511 goto out_dput;
512
513 whiteout = ovl_whiteout(workdir, dentry);
514 err = PTR_ERR(whiteout);
515 if (IS_ERR(whiteout))
516 goto out_unlock;
517
518 if (type == OVL_PATH_LOWER) {
519 upper = lookup_one_len(dentry->d_name.name, upperdir,
520 dentry->d_name.len);
521 err = PTR_ERR(upper);
522 if (IS_ERR(upper))
523 goto kill_whiteout;
524
525 err = ovl_do_rename(wdir, whiteout, udir, upper, 0);
526 dput(upper);
527 if (err)
528 goto kill_whiteout;
529 } else {
530 int flags = 0;
531
532 upper = ovl_dentry_upper(dentry);
533 if (opaquedir)
534 upper = opaquedir;
535 err = -ESTALE;
536 if (upper->d_parent != upperdir)
537 goto kill_whiteout;
538
539 if (is_dir)
540 flags |= RENAME_EXCHANGE;
541
542 err = ovl_do_rename(wdir, whiteout, udir, upper, flags);
543 if (err)
544 goto kill_whiteout;
545
546 if (is_dir)
547 ovl_cleanup(wdir, upper);
548 }
549 ovl_dentry_version_inc(dentry->d_parent);
550out_d_drop:
551 d_drop(dentry);
552 dput(whiteout);
553out_unlock:
554 unlock_rename(workdir, upperdir);
555out_dput:
556 dput(opaquedir);
557out:
558 return err;
559
560kill_whiteout:
561 ovl_cleanup(wdir, whiteout);
562 goto out_d_drop;
563}
564
565static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
566{
567 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
568 struct inode *dir = upperdir->d_inode;
569 struct dentry *upper = ovl_dentry_upper(dentry);
570 int err;
571
572 mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
573 err = -ESTALE;
574 if (upper->d_parent == upperdir) {
575 /* Don't let d_delete() think it can reset d_inode */
576 dget(upper);
577 if (is_dir)
578 err = vfs_rmdir(dir, upper);
579 else
580 err = vfs_unlink(dir, upper, NULL);
581 dput(upper);
582 ovl_dentry_version_inc(dentry->d_parent);
583 }
584
585 /*
586 * Keeping this dentry hashed would mean having to release
587 * upperpath/lowerpath, which could only be done if we are the
588 * sole user of this dentry. Too tricky... Just unhash for
589 * now.
590 */
591 d_drop(dentry);
592 mutex_unlock(&dir->i_mutex);
593
594 return err;
595}
596
597static inline int ovl_check_sticky(struct dentry *dentry)
598{
599 struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode;
600 struct inode *inode = ovl_dentry_real(dentry)->d_inode;
601
602 if (check_sticky(dir, inode))
603 return -EPERM;
604
605 return 0;
606}
607
608static int ovl_do_remove(struct dentry *dentry, bool is_dir)
609{
610 enum ovl_path_type type;
611 int err;
612
613 err = ovl_check_sticky(dentry);
614 if (err)
615 goto out;
616
617 err = ovl_want_write(dentry);
618 if (err)
619 goto out;
620
621 err = ovl_copy_up(dentry->d_parent);
622 if (err)
623 goto out_drop_write;
624
625 type = ovl_path_type(dentry);
626 if (type == OVL_PATH_PURE_UPPER) {
627 err = ovl_remove_upper(dentry, is_dir);
628 } else {
629 const struct cred *old_cred;
630 struct cred *override_cred;
631
632 err = -ENOMEM;
633 override_cred = prepare_creds();
634 if (!override_cred)
635 goto out_drop_write;
636
637 /*
638 * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir
639 * CAP_DAC_OVERRIDE for create in workdir, rename
640 * CAP_FOWNER for removing whiteout from sticky dir
641 * CAP_FSETID for chmod of opaque dir
642 * CAP_CHOWN for chown of opaque dir
643 */
644 cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
645 cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
646 cap_raise(override_cred->cap_effective, CAP_FOWNER);
647 cap_raise(override_cred->cap_effective, CAP_FSETID);
648 cap_raise(override_cred->cap_effective, CAP_CHOWN);
649 old_cred = override_creds(override_cred);
650
651 err = ovl_remove_and_whiteout(dentry, type, is_dir);
652
653 revert_creds(old_cred);
654 put_cred(override_cred);
655 }
656out_drop_write:
657 ovl_drop_write(dentry);
658out:
659 return err;
660}
661
662static int ovl_unlink(struct inode *dir, struct dentry *dentry)
663{
664 return ovl_do_remove(dentry, false);
665}
666
667static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
668{
669 return ovl_do_remove(dentry, true);
670}
671
672static int ovl_rename2(struct inode *olddir, struct dentry *old,
673 struct inode *newdir, struct dentry *new,
674 unsigned int flags)
675{
676 int err;
677 enum ovl_path_type old_type;
678 enum ovl_path_type new_type;
679 struct dentry *old_upperdir;
680 struct dentry *new_upperdir;
681 struct dentry *olddentry;
682 struct dentry *newdentry;
683 struct dentry *trap;
684 bool old_opaque;
685 bool new_opaque;
686 bool new_create = false;
687 bool cleanup_whiteout = false;
688 bool overwrite = !(flags & RENAME_EXCHANGE);
689 bool is_dir = S_ISDIR(old->d_inode->i_mode);
690 bool new_is_dir = false;
691 struct dentry *opaquedir = NULL;
692 const struct cred *old_cred = NULL;
693 struct cred *override_cred = NULL;
694
695 err = -EINVAL;
696 if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
697 goto out;
698
699 flags &= ~RENAME_NOREPLACE;
700
701 err = ovl_check_sticky(old);
702 if (err)
703 goto out;
704
705 /* Don't copy up directory trees */
706 old_type = ovl_path_type(old);
707 err = -EXDEV;
708 if ((old_type == OVL_PATH_LOWER || old_type == OVL_PATH_MERGE) && is_dir)
709 goto out;
710
711 if (new->d_inode) {
712 err = ovl_check_sticky(new);
713 if (err)
714 goto out;
715
716 if (S_ISDIR(new->d_inode->i_mode))
717 new_is_dir = true;
718
719 new_type = ovl_path_type(new);
720 err = -EXDEV;
721 if (!overwrite && (new_type == OVL_PATH_LOWER || new_type == OVL_PATH_MERGE) && new_is_dir)
722 goto out;
723
724 err = 0;
725 if (new_type == OVL_PATH_LOWER && old_type == OVL_PATH_LOWER) {
726 if (ovl_dentry_lower(old)->d_inode ==
727 ovl_dentry_lower(new)->d_inode)
728 goto out;
729 }
730 if (new_type != OVL_PATH_LOWER && old_type != OVL_PATH_LOWER) {
731 if (ovl_dentry_upper(old)->d_inode ==
732 ovl_dentry_upper(new)->d_inode)
733 goto out;
734 }
735 } else {
736 if (ovl_dentry_is_opaque(new))
737 new_type = OVL_PATH_UPPER;
738 else
739 new_type = OVL_PATH_PURE_UPPER;
740 }
741
742 err = ovl_want_write(old);
743 if (err)
744 goto out;
745
746 err = ovl_copy_up(old);
747 if (err)
748 goto out_drop_write;
749
750 err = ovl_copy_up(new->d_parent);
751 if (err)
752 goto out_drop_write;
753 if (!overwrite) {
754 err = ovl_copy_up(new);
755 if (err)
756 goto out_drop_write;
757 }
758
759 old_opaque = old_type != OVL_PATH_PURE_UPPER;
760 new_opaque = new_type != OVL_PATH_PURE_UPPER;
761
762 if (old_opaque || new_opaque) {
763 err = -ENOMEM;
764 override_cred = prepare_creds();
765 if (!override_cred)
766 goto out_drop_write;
767
768 /*
769 * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir
770 * CAP_DAC_OVERRIDE for create in workdir
771 * CAP_FOWNER for removing whiteout from sticky dir
772 * CAP_FSETID for chmod of opaque dir
773 * CAP_CHOWN for chown of opaque dir
774 */
775 cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
776 cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
777 cap_raise(override_cred->cap_effective, CAP_FOWNER);
778 cap_raise(override_cred->cap_effective, CAP_FSETID);
779 cap_raise(override_cred->cap_effective, CAP_CHOWN);
780 old_cred = override_creds(override_cred);
781 }
782
783 if (overwrite && (new_type == OVL_PATH_LOWER || new_type == OVL_PATH_MERGE) && new_is_dir) {
784 opaquedir = ovl_check_empty_and_clear(new, new_type);
785 err = PTR_ERR(opaquedir);
786 if (IS_ERR(opaquedir)) {
787 opaquedir = NULL;
788 goto out_revert_creds;
789 }
790 }
791
792 if (overwrite) {
793 if (old_opaque) {
794 if (new->d_inode || !new_opaque) {
795 /* Whiteout source */
796 flags |= RENAME_WHITEOUT;
797 } else {
798 /* Switch whiteouts */
799 flags |= RENAME_EXCHANGE;
800 }
801 } else if (is_dir && !new->d_inode && new_opaque) {
802 flags |= RENAME_EXCHANGE;
803 cleanup_whiteout = true;
804 }
805 }
806
807 old_upperdir = ovl_dentry_upper(old->d_parent);
808 new_upperdir = ovl_dentry_upper(new->d_parent);
809
810 trap = lock_rename(new_upperdir, old_upperdir);
811
812 olddentry = ovl_dentry_upper(old);
813 newdentry = ovl_dentry_upper(new);
814 if (newdentry) {
815 if (opaquedir) {
816 newdentry = opaquedir;
817 opaquedir = NULL;
818 } else {
819 dget(newdentry);
820 }
821 } else {
822 new_create = true;
823 newdentry = lookup_one_len(new->d_name.name, new_upperdir,
824 new->d_name.len);
825 err = PTR_ERR(newdentry);
826 if (IS_ERR(newdentry))
827 goto out_unlock;
828 }
829
830 err = -ESTALE;
831 if (olddentry->d_parent != old_upperdir)
832 goto out_dput;
833 if (newdentry->d_parent != new_upperdir)
834 goto out_dput;
835 if (olddentry == trap)
836 goto out_dput;
837 if (newdentry == trap)
838 goto out_dput;
839
840 if (is_dir && !old_opaque && new_opaque) {
841 err = ovl_set_opaque(olddentry);
842 if (err)
843 goto out_dput;
844 }
845 if (!overwrite && new_is_dir && old_opaque && !new_opaque) {
846 err = ovl_set_opaque(newdentry);
847 if (err)
848 goto out_dput;
849 }
850
851 if (old_opaque || new_opaque) {
852 err = ovl_do_rename(old_upperdir->d_inode, olddentry,
853 new_upperdir->d_inode, newdentry,
854 flags);
855 } else {
856 /* No debug for the plain case */
857 BUG_ON(flags & ~RENAME_EXCHANGE);
858 err = vfs_rename(old_upperdir->d_inode, olddentry,
859 new_upperdir->d_inode, newdentry,
860 NULL, flags);
861 }
862
863 if (err) {
864 if (is_dir && !old_opaque && new_opaque)
865 ovl_remove_opaque(olddentry);
866 if (!overwrite && new_is_dir && old_opaque && !new_opaque)
867 ovl_remove_opaque(newdentry);
868 goto out_dput;
869 }
870
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
876 if (old_opaque != new_opaque) {
877 ovl_dentry_set_opaque(old, new_opaque);
878 if (!overwrite)
879 ovl_dentry_set_opaque(new, old_opaque);
880 }
881
882 if (cleanup_whiteout)
883 ovl_cleanup(old_upperdir->d_inode, newdentry);
884
885 ovl_dentry_version_inc(old->d_parent);
886 ovl_dentry_version_inc(new->d_parent);
887
888out_dput:
889 dput(newdentry);
890out_unlock:
891 unlock_rename(new_upperdir, old_upperdir);
892out_revert_creds:
893 if (old_opaque || new_opaque) {
894 revert_creds(old_cred);
895 put_cred(override_cred);
896 }
897out_drop_write:
898 ovl_drop_write(old);
899out:
900 dput(opaquedir);
901 return err;
902}
903
904const struct inode_operations ovl_dir_inode_operations = {
905 .lookup = ovl_lookup,
906 .mkdir = ovl_mkdir,
907 .symlink = ovl_symlink,
908 .unlink = ovl_unlink,
909 .rmdir = ovl_rmdir,
910 .rename2 = ovl_rename2,
911 .link = ovl_link,
912 .setattr = ovl_setattr,
913 .create = ovl_create,
914 .mknod = ovl_mknod,
915 .permission = ovl_permission,
916 .getattr = ovl_dir_getattr,
917 .setxattr = ovl_setxattr,
918 .getxattr = ovl_getxattr,
919 .listxattr = ovl_listxattr,
920 .removexattr = ovl_removexattr,
921};
generated by cgit v1.2.2 (git 2.25.0) at 2025-06-01 05:07:36 -0400