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-rw-r--r--fs/overlayfs/dir.c928
1 files changed, 928 insertions, 0 deletions
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
new file mode 100644
index 000000000000..8ffc4b980f1b
--- /dev/null
+++ b/fs/overlayfs/dir.c
@@ -0,0 +1,928 @@
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{
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);
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 }
307
308 ovl_cache_free(&list);
309
310 return ret;
311}
312
313static 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;
365out_dput2:
366 dput(upper);
367out_dput:
368 dput(newdentry);
369out_unlock:
370 unlock_rename(workdir, upperdir);
371out:
372 return err;
373
374out_cleanup:
375 ovl_cleanup(wdir, newdentry);
376 goto out_dput2;
377}
378
379static 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;
428out_iput:
429 iput(inode);
430out:
431 return err;
432}
433
434static 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
448static 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
454static 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
459static 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
469static 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
475static 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
492out_drop_write:
493 ovl_drop_write(old);
494out:
495 return err;
496}
497
498static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
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
509 if (is_dir) {
510 opaquedir = ovl_check_empty_and_clear(dentry);
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
525 upper = ovl_dentry_upper(dentry);
526 if (!upper) {
527 upper = lookup_one_len(dentry->d_name.name, upperdir,
528 dentry->d_name.len);
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
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);
557out_d_drop:
558 d_drop(dentry);
559 dput(whiteout);
560out_unlock:
561 unlock_rename(workdir, upperdir);
562out_dput:
563 dput(opaquedir);
564out:
565 return err;
566
567kill_whiteout:
568 ovl_cleanup(wdir, whiteout);
569 goto out_d_drop;
570}
571
572static 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
604static 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
615static 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);
633 if (type == OVL_PATH_PURE_UPPER) {
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
658 err = ovl_remove_and_whiteout(dentry, is_dir);
659
660 revert_creds(old_cred);
661 put_cred(override_cred);
662 }
663out_drop_write:
664 ovl_drop_write(dentry);
665out:
666 return err;
667}
668
669static int ovl_unlink(struct inode *dir, struct dentry *dentry)
670{
671 return ovl_do_remove(dentry, false);
672}
673
674static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
675{
676 return ovl_do_remove(dentry, true);
677}
678
679static 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;
715 if ((old_type == OVL_PATH_LOWER || old_type == OVL_PATH_MERGE) && is_dir)
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;
728 if (!overwrite && (new_type == OVL_PATH_LOWER || new_type == OVL_PATH_MERGE) && new_is_dir)
729 goto out;
730
731 err = 0;
732 if (new_type == OVL_PATH_LOWER && old_type == OVL_PATH_LOWER) {
733 if (ovl_dentry_lower(old)->d_inode ==
734 ovl_dentry_lower(new)->d_inode)
735 goto out;
736 }
737 if (new_type != OVL_PATH_LOWER && old_type != OVL_PATH_LOWER) {
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))
744 new_type = OVL_PATH_UPPER;
745 else
746 new_type = OVL_PATH_PURE_UPPER;
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
766 old_opaque = old_type != OVL_PATH_PURE_UPPER;
767 new_opaque = new_type != OVL_PATH_PURE_UPPER;
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
790 if (overwrite && (new_type == OVL_PATH_LOWER || new_type == OVL_PATH_MERGE) && new_is_dir) {
791 opaquedir = ovl_check_empty_and_clear(new);
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
895out_dput:
896 dput(newdentry);
897out_unlock:
898 unlock_rename(new_upperdir, old_upperdir);
899out_revert_creds:
900 if (old_opaque || new_opaque) {
901 revert_creds(old_cred);
902 put_cred(override_cred);
903 }
904out_drop_write:
905 ovl_drop_write(old);
906out:
907 dput(opaquedir);
908 return err;
909}
910
911const 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};
generated by cgit v1.2.2 (git 2.25.0) at 2025-06-01 03:16:53 -0400