MIPS: KVM: Use raw_cpu_has_fpu in kvm_mips_guest_can_have_fpu()
[deliverable/linux.git] / fs / overlayfs / dir.c
CommitLineData
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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);
e36cb0b8 22 if (d_is_dir(wdentry))
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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
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{
cead89bb 121 return ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0);
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122}
123
124static void ovl_remove_opaque(struct dentry *upperdentry)
125{
126 int err;
127
cead89bb 128 err = ovl_do_removexattr(upperdentry, OVL_XATTR_OPAQUE);
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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 */
1afaba1e 155 if (OVL_TYPE_MERGE(type))
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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
5955102c 170 inode_lock_nested(udir, I_MUTEX_PARENT);
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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:
5955102c 188 inode_unlock(udir);
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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
cc6f67bc
MS
225 if (WARN_ON(!workdir))
226 return ERR_PTR(-EROFS);
227
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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);
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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
280out_cleanup:
281 ovl_cleanup(wdir, opaquedir);
282out_dput:
283 dput(opaquedir);
284out_unlock:
285 unlock_rename(workdir, upperdir);
286out:
287 return ERR_PTR(err);
288}
289
a105d685 290static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry)
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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 }
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310
311 ovl_cache_free(&list);
312
313 return ret;
314}
315
316static 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;
371out_dput2:
372 dput(upper);
373out_dput:
374 dput(newdentry);
375out_unlock:
376 unlock_rename(workdir, upperdir);
377out:
378 return err;
379
380out_cleanup:
381 ovl_cleanup(wdir, newdentry);
382 goto out_dput2;
383}
384
385static 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;
e9be9d5e 408
3fe6e52f 409 old_cred = ovl_override_creds(dentry->d_sb);
e9be9d5e
MS
410
411 err = ovl_create_over_whiteout(dentry, inode, &stat, link,
412 hardlink);
413
414 revert_creds(old_cred);
e9be9d5e
MS
415 }
416
417 if (!err)
418 inode = NULL;
419out_iput:
420 iput(inode);
421out:
422 return err;
423}
424
425static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
426 const char *link)
427{
428 int err;
429
430 err = ovl_want_write(dentry);
431 if (!err) {
432 err = ovl_create_or_link(dentry, mode, rdev, link, NULL);
433 ovl_drop_write(dentry);
434 }
435
436 return err;
437}
438
439static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode,
440 bool excl)
441{
442 return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
443}
444
445static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
446{
447 return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL);
448}
449
450static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
451 dev_t rdev)
452{
453 /* Don't allow creation of "whiteout" on overlay */
454 if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
455 return -EPERM;
456
457 return ovl_create_object(dentry, mode, rdev, NULL);
458}
459
460static int ovl_symlink(struct inode *dir, struct dentry *dentry,
461 const char *link)
462{
463 return ovl_create_object(dentry, S_IFLNK, 0, link);
464}
465
466static int ovl_link(struct dentry *old, struct inode *newdir,
467 struct dentry *new)
468{
469 int err;
470 struct dentry *upper;
471
472 err = ovl_want_write(old);
473 if (err)
474 goto out;
475
476 err = ovl_copy_up(old);
477 if (err)
478 goto out_drop_write;
479
480 upper = ovl_dentry_upper(old);
481 err = ovl_create_or_link(new, upper->d_inode->i_mode, 0, NULL, upper);
482
483out_drop_write:
484 ovl_drop_write(old);
485out:
486 return err;
487}
488
a105d685 489static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
e9be9d5e
MS
490{
491 struct dentry *workdir = ovl_workdir(dentry);
492 struct inode *wdir = workdir->d_inode;
493 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
494 struct inode *udir = upperdir->d_inode;
495 struct dentry *whiteout;
496 struct dentry *upper;
497 struct dentry *opaquedir = NULL;
498 int err;
499
cc6f67bc
MS
500 if (WARN_ON(!workdir))
501 return -EROFS;
502
d377c5eb
MS
503 if (is_dir) {
504 if (OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) {
505 opaquedir = ovl_check_empty_and_clear(dentry);
506 err = PTR_ERR(opaquedir);
507 if (IS_ERR(opaquedir))
508 goto out;
509 } else {
510 LIST_HEAD(list);
511
512 /*
513 * When removing an empty opaque directory, then it
514 * makes no sense to replace it with an exact replica of
515 * itself. But emptiness still needs to be checked.
516 */
517 err = ovl_check_empty_dir(dentry, &list);
518 ovl_cache_free(&list);
519 if (err)
520 goto out;
521 }
e9be9d5e
MS
522 }
523
524 err = ovl_lock_rename_workdir(workdir, upperdir);
525 if (err)
526 goto out_dput;
527
528 whiteout = ovl_whiteout(workdir, dentry);
529 err = PTR_ERR(whiteout);
530 if (IS_ERR(whiteout))
531 goto out_unlock;
532
a105d685
MS
533 upper = ovl_dentry_upper(dentry);
534 if (!upper) {
e9be9d5e 535 upper = lookup_one_len(dentry->d_name.name, upperdir,
a105d685 536 dentry->d_name.len);
e9be9d5e
MS
537 err = PTR_ERR(upper);
538 if (IS_ERR(upper))
539 goto kill_whiteout;
540
541 err = ovl_do_rename(wdir, whiteout, udir, upper, 0);
542 dput(upper);
543 if (err)
544 goto kill_whiteout;
545 } else {
546 int flags = 0;
547
e9be9d5e
MS
548 if (opaquedir)
549 upper = opaquedir;
550 err = -ESTALE;
551 if (upper->d_parent != upperdir)
552 goto kill_whiteout;
553
554 if (is_dir)
555 flags |= RENAME_EXCHANGE;
556
557 err = ovl_do_rename(wdir, whiteout, udir, upper, flags);
558 if (err)
559 goto kill_whiteout;
560
561 if (is_dir)
562 ovl_cleanup(wdir, upper);
563 }
564 ovl_dentry_version_inc(dentry->d_parent);
565out_d_drop:
566 d_drop(dentry);
567 dput(whiteout);
568out_unlock:
569 unlock_rename(workdir, upperdir);
570out_dput:
571 dput(opaquedir);
572out:
573 return err;
574
575kill_whiteout:
576 ovl_cleanup(wdir, whiteout);
577 goto out_d_drop;
578}
579
580static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
581{
582 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
583 struct inode *dir = upperdir->d_inode;
11f37104 584 struct dentry *upper;
e9be9d5e
MS
585 int err;
586
5955102c 587 inode_lock_nested(dir, I_MUTEX_PARENT);
11f37104
MS
588 upper = lookup_one_len(dentry->d_name.name, upperdir,
589 dentry->d_name.len);
590 err = PTR_ERR(upper);
591 if (IS_ERR(upper))
592 goto out_unlock;
593
e9be9d5e 594 err = -ESTALE;
11f37104 595 if (upper == ovl_dentry_upper(dentry)) {
e9be9d5e
MS
596 if (is_dir)
597 err = vfs_rmdir(dir, upper);
598 else
599 err = vfs_unlink(dir, upper, NULL);
e9be9d5e
MS
600 ovl_dentry_version_inc(dentry->d_parent);
601 }
11f37104 602 dput(upper);
e9be9d5e
MS
603
604 /*
605 * Keeping this dentry hashed would mean having to release
606 * upperpath/lowerpath, which could only be done if we are the
607 * sole user of this dentry. Too tricky... Just unhash for
608 * now.
609 */
ce9113bb
RW
610 if (!err)
611 d_drop(dentry);
11f37104 612out_unlock:
5955102c 613 inode_unlock(dir);
e9be9d5e
MS
614
615 return err;
616}
617
618static inline int ovl_check_sticky(struct dentry *dentry)
619{
620 struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode;
621 struct inode *inode = ovl_dentry_real(dentry)->d_inode;
622
623 if (check_sticky(dir, inode))
624 return -EPERM;
625
626 return 0;
627}
628
629static int ovl_do_remove(struct dentry *dentry, bool is_dir)
630{
631 enum ovl_path_type type;
632 int err;
633
634 err = ovl_check_sticky(dentry);
635 if (err)
636 goto out;
637
638 err = ovl_want_write(dentry);
639 if (err)
640 goto out;
641
642 err = ovl_copy_up(dentry->d_parent);
643 if (err)
644 goto out_drop_write;
645
646 type = ovl_path_type(dentry);
1afaba1e 647 if (OVL_TYPE_PURE_UPPER(type)) {
e9be9d5e
MS
648 err = ovl_remove_upper(dentry, is_dir);
649 } else {
3fe6e52f 650 const struct cred *old_cred = ovl_override_creds(dentry->d_sb);
e9be9d5e 651
a105d685 652 err = ovl_remove_and_whiteout(dentry, is_dir);
e9be9d5e
MS
653
654 revert_creds(old_cred);
e9be9d5e
MS
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;
e9be9d5e
MS
686 bool cleanup_whiteout = false;
687 bool overwrite = !(flags & RENAME_EXCHANGE);
e36cb0b8 688 bool is_dir = d_is_dir(old);
e9be9d5e
MS
689 bool new_is_dir = false;
690 struct dentry *opaquedir = NULL;
691 const struct cred *old_cred = NULL;
e9be9d5e
MS
692
693 err = -EINVAL;
694 if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
695 goto out;
696
697 flags &= ~RENAME_NOREPLACE;
698
699 err = ovl_check_sticky(old);
700 if (err)
701 goto out;
702
703 /* Don't copy up directory trees */
704 old_type = ovl_path_type(old);
705 err = -EXDEV;
1afaba1e 706 if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir)
e9be9d5e
MS
707 goto out;
708
709 if (new->d_inode) {
710 err = ovl_check_sticky(new);
711 if (err)
712 goto out;
713
e36cb0b8 714 if (d_is_dir(new))
e9be9d5e
MS
715 new_is_dir = true;
716
717 new_type = ovl_path_type(new);
718 err = -EXDEV;
1afaba1e 719 if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir)
e9be9d5e
MS
720 goto out;
721
722 err = 0;
1afaba1e 723 if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) {
e9be9d5e
MS
724 if (ovl_dentry_lower(old)->d_inode ==
725 ovl_dentry_lower(new)->d_inode)
726 goto out;
727 }
1afaba1e 728 if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) {
e9be9d5e
MS
729 if (ovl_dentry_upper(old)->d_inode ==
730 ovl_dentry_upper(new)->d_inode)
731 goto out;
732 }
733 } else {
734 if (ovl_dentry_is_opaque(new))
1afaba1e 735 new_type = __OVL_PATH_UPPER;
e9be9d5e 736 else
1afaba1e 737 new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE;
e9be9d5e
MS
738 }
739
740 err = ovl_want_write(old);
741 if (err)
742 goto out;
743
744 err = ovl_copy_up(old);
745 if (err)
746 goto out_drop_write;
747
748 err = ovl_copy_up(new->d_parent);
749 if (err)
750 goto out_drop_write;
751 if (!overwrite) {
752 err = ovl_copy_up(new);
753 if (err)
754 goto out_drop_write;
755 }
756
1afaba1e
MS
757 old_opaque = !OVL_TYPE_PURE_UPPER(old_type);
758 new_opaque = !OVL_TYPE_PURE_UPPER(new_type);
e9be9d5e 759
3fe6e52f
AM
760 if (old_opaque || new_opaque)
761 old_cred = ovl_override_creds(old->d_sb);
e9be9d5e 762
1afaba1e 763 if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) {
a105d685 764 opaquedir = ovl_check_empty_and_clear(new);
e9be9d5e
MS
765 err = PTR_ERR(opaquedir);
766 if (IS_ERR(opaquedir)) {
767 opaquedir = NULL;
768 goto out_revert_creds;
769 }
770 }
771
772 if (overwrite) {
773 if (old_opaque) {
774 if (new->d_inode || !new_opaque) {
775 /* Whiteout source */
776 flags |= RENAME_WHITEOUT;
777 } else {
778 /* Switch whiteouts */
779 flags |= RENAME_EXCHANGE;
780 }
781 } else if (is_dir && !new->d_inode && new_opaque) {
782 flags |= RENAME_EXCHANGE;
783 cleanup_whiteout = true;
784 }
785 }
786
787 old_upperdir = ovl_dentry_upper(old->d_parent);
788 new_upperdir = ovl_dentry_upper(new->d_parent);
789
790 trap = lock_rename(new_upperdir, old_upperdir);
791
11f37104
MS
792
793 olddentry = lookup_one_len(old->d_name.name, old_upperdir,
794 old->d_name.len);
795 err = PTR_ERR(olddentry);
796 if (IS_ERR(olddentry))
797 goto out_unlock;
798
799 err = -ESTALE;
800 if (olddentry != ovl_dentry_upper(old))
801 goto out_dput_old;
802
803 newdentry = lookup_one_len(new->d_name.name, new_upperdir,
804 new->d_name.len);
805 err = PTR_ERR(newdentry);
806 if (IS_ERR(newdentry))
807 goto out_dput_old;
808
809 err = -ESTALE;
810 if (ovl_dentry_upper(new)) {
e9be9d5e 811 if (opaquedir) {
11f37104
MS
812 if (newdentry != opaquedir)
813 goto out_dput;
e9be9d5e 814 } else {
11f37104
MS
815 if (newdentry != ovl_dentry_upper(new))
816 goto out_dput;
e9be9d5e
MS
817 }
818 } else {
11f37104
MS
819 if (!d_is_negative(newdentry) &&
820 (!new_opaque || !ovl_is_whiteout(newdentry)))
821 goto out_dput;
e9be9d5e
MS
822 }
823
e9be9d5e
MS
824 if (olddentry == trap)
825 goto out_dput;
826 if (newdentry == trap)
827 goto out_dput;
828
829 if (is_dir && !old_opaque && new_opaque) {
830 err = ovl_set_opaque(olddentry);
831 if (err)
832 goto out_dput;
833 }
834 if (!overwrite && new_is_dir && old_opaque && !new_opaque) {
835 err = ovl_set_opaque(newdentry);
836 if (err)
837 goto out_dput;
838 }
839
840 if (old_opaque || new_opaque) {
841 err = ovl_do_rename(old_upperdir->d_inode, olddentry,
842 new_upperdir->d_inode, newdentry,
843 flags);
844 } else {
845 /* No debug for the plain case */
846 BUG_ON(flags & ~RENAME_EXCHANGE);
847 err = vfs_rename(old_upperdir->d_inode, olddentry,
848 new_upperdir->d_inode, newdentry,
849 NULL, flags);
850 }
851
852 if (err) {
853 if (is_dir && !old_opaque && new_opaque)
854 ovl_remove_opaque(olddentry);
855 if (!overwrite && new_is_dir && old_opaque && !new_opaque)
856 ovl_remove_opaque(newdentry);
857 goto out_dput;
858 }
859
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
45d11738
KK
865 /*
866 * Old dentry now lives in different location. Dentries in
867 * lowerstack are stale. We cannot drop them here because
868 * access to them is lockless. This could be only pure upper
869 * or opaque directory - numlower is zero. Or upper non-dir
870 * entry - its pureness is tracked by flag opaque.
871 */
e9be9d5e
MS
872 if (old_opaque != new_opaque) {
873 ovl_dentry_set_opaque(old, new_opaque);
874 if (!overwrite)
875 ovl_dentry_set_opaque(new, old_opaque);
876 }
877
878 if (cleanup_whiteout)
879 ovl_cleanup(old_upperdir->d_inode, newdentry);
880
881 ovl_dentry_version_inc(old->d_parent);
882 ovl_dentry_version_inc(new->d_parent);
883
884out_dput:
885 dput(newdentry);
11f37104
MS
886out_dput_old:
887 dput(olddentry);
e9be9d5e
MS
888out_unlock:
889 unlock_rename(new_upperdir, old_upperdir);
890out_revert_creds:
3fe6e52f 891 if (old_opaque || new_opaque)
e9be9d5e 892 revert_creds(old_cred);
e9be9d5e
MS
893out_drop_write:
894 ovl_drop_write(old);
895out:
896 dput(opaquedir);
897 return err;
898}
899
900const struct inode_operations ovl_dir_inode_operations = {
901 .lookup = ovl_lookup,
902 .mkdir = ovl_mkdir,
903 .symlink = ovl_symlink,
904 .unlink = ovl_unlink,
905 .rmdir = ovl_rmdir,
906 .rename2 = ovl_rename2,
907 .link = ovl_link,
908 .setattr = ovl_setattr,
909 .create = ovl_create,
910 .mknod = ovl_mknod,
911 .permission = ovl_permission,
912 .getattr = ovl_dir_getattr,
913 .setxattr = ovl_setxattr,
914 .getxattr = ovl_getxattr,
915 .listxattr = ovl_listxattr,
916 .removexattr = ovl_removexattr,
917};
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