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5
6
7#include <linux/module.h>
8#include <linux/fs.h>
9#include <linux/slab.h>
10#include <linux/file.h>
11#include <linux/fileattr.h>
12#include <linux/splice.h>
13#include <linux/xattr.h>
14#include <linux/security.h>
15#include <linux/uaccess.h>
16#include <linux/sched/signal.h>
17#include <linux/cred.h>
18#include <linux/namei.h>
19#include <linux/fdtable.h>
20#include <linux/ratelimit.h>
21#include <linux/exportfs.h>
22#include "overlayfs.h"
23
24#define OVL_COPY_UP_CHUNK_SIZE (1 << 20)
25
26static int ovl_ccup_set(const char *buf, const struct kernel_param *param)
27{
28 pr_warn("\"check_copy_up\" module option is obsolete\n");
29 return 0;
30}
31
32static int ovl_ccup_get(char *buf, const struct kernel_param *param)
33{
34 return sprintf(buf, "N\n");
35}
36
37module_param_call(check_copy_up, ovl_ccup_set, ovl_ccup_get, NULL, 0644);
38MODULE_PARM_DESC(check_copy_up, "Obsolete; does nothing");
39
40static bool ovl_must_copy_xattr(const char *name)
41{
42 return !strcmp(name, XATTR_POSIX_ACL_ACCESS) ||
43 !strcmp(name, XATTR_POSIX_ACL_DEFAULT) ||
44 !strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN);
45}
46
47int ovl_copy_xattr(struct super_block *sb, struct dentry *old,
48 struct dentry *new)
49{
50 ssize_t list_size, size, value_size = 0;
51 char *buf, *name, *value = NULL;
52 int error = 0;
53 size_t slen;
54
55 if (!(old->d_inode->i_opflags & IOP_XATTR) ||
56 !(new->d_inode->i_opflags & IOP_XATTR))
57 return 0;
58
59 list_size = vfs_listxattr(old, NULL, 0);
60 if (list_size <= 0) {
61 if (list_size == -EOPNOTSUPP)
62 return 0;
63 return list_size;
64 }
65
66 buf = kvzalloc(list_size, GFP_KERNEL);
67 if (!buf)
68 return -ENOMEM;
69
70 list_size = vfs_listxattr(old, buf, list_size);
71 if (list_size <= 0) {
72 error = list_size;
73 goto out;
74 }
75
76 for (name = buf; list_size; name += slen) {
77 slen = strnlen(name, list_size) + 1;
78
79
80 if (WARN_ON(slen > list_size)) {
81 error = -EIO;
82 break;
83 }
84 list_size -= slen;
85
86 if (ovl_is_private_xattr(sb, name))
87 continue;
88
89 error = security_inode_copy_up_xattr(name);
90 if (error < 0 && error != -EOPNOTSUPP)
91 break;
92 if (error == 1) {
93 error = 0;
94 continue;
95 }
96retry:
97 size = vfs_getxattr(&init_user_ns, old, name, value, value_size);
98 if (size == -ERANGE)
99 size = vfs_getxattr(&init_user_ns, old, name, NULL, 0);
100
101 if (size < 0) {
102 error = size;
103 break;
104 }
105
106 if (size > value_size) {
107 void *new;
108
109 new = kvmalloc(size, GFP_KERNEL);
110 if (!new) {
111 error = -ENOMEM;
112 break;
113 }
114 kvfree(value);
115 value = new;
116 value_size = size;
117 goto retry;
118 }
119
120 error = vfs_setxattr(&init_user_ns, new, name, value, size, 0);
121 if (error) {
122 if (error != -EOPNOTSUPP || ovl_must_copy_xattr(name))
123 break;
124
125
126 error = 0;
127 }
128 }
129 kvfree(value);
130out:
131 kvfree(buf);
132 return error;
133}
134
135static int ovl_copy_fileattr(struct inode *inode, struct path *old,
136 struct path *new)
137{
138 struct fileattr oldfa = { .flags_valid = true };
139 struct fileattr newfa = { .flags_valid = true };
140 int err;
141
142 err = ovl_real_fileattr_get(old, &oldfa);
143 if (err) {
144
145 if (err == -ENOTTY || err == -EINVAL)
146 return 0;
147 pr_warn("failed to retrieve lower fileattr (%pd2, err=%i)\n",
148 old->dentry, err);
149 return err;
150 }
151
152
153
154
155
156
157
158 if (oldfa.flags & OVL_PROT_FS_FLAGS_MASK) {
159 err = ovl_set_protattr(inode, new->dentry, &oldfa);
160 if (err == -EPERM)
161 pr_warn_once("copying fileattr: no xattr on upper\n");
162 else if (err)
163 return err;
164 }
165
166
167 if (!(oldfa.flags & OVL_COPY_FS_FLAGS_MASK))
168 return 0;
169
170 err = ovl_real_fileattr_get(new, &newfa);
171 if (err) {
172
173
174
175
176 if (err == -ENOTTY || err == -EINVAL) {
177 pr_warn_once("copying fileattr: no support on upper\n");
178 return 0;
179 }
180 pr_warn("failed to retrieve upper fileattr (%pd2, err=%i)\n",
181 new->dentry, err);
182 return err;
183 }
184
185 BUILD_BUG_ON(OVL_COPY_FS_FLAGS_MASK & ~FS_COMMON_FL);
186 newfa.flags &= ~OVL_COPY_FS_FLAGS_MASK;
187 newfa.flags |= (oldfa.flags & OVL_COPY_FS_FLAGS_MASK);
188
189 BUILD_BUG_ON(OVL_COPY_FSX_FLAGS_MASK & ~FS_XFLAG_COMMON);
190 newfa.fsx_xflags &= ~OVL_COPY_FSX_FLAGS_MASK;
191 newfa.fsx_xflags |= (oldfa.fsx_xflags & OVL_COPY_FSX_FLAGS_MASK);
192
193 return ovl_real_fileattr_set(new, &newfa);
194}
195
196static int ovl_copy_up_data(struct ovl_fs *ofs, struct path *old,
197 struct path *new, loff_t len)
198{
199 struct file *old_file;
200 struct file *new_file;
201 loff_t old_pos = 0;
202 loff_t new_pos = 0;
203 loff_t cloned;
204 loff_t data_pos = -1;
205 loff_t hole_len;
206 bool skip_hole = false;
207 int error = 0;
208
209 if (len == 0)
210 return 0;
211
212 old_file = ovl_path_open(old, O_LARGEFILE | O_RDONLY);
213 if (IS_ERR(old_file))
214 return PTR_ERR(old_file);
215
216 new_file = ovl_path_open(new, O_LARGEFILE | O_WRONLY);
217 if (IS_ERR(new_file)) {
218 error = PTR_ERR(new_file);
219 goto out_fput;
220 }
221
222
223 cloned = do_clone_file_range(old_file, 0, new_file, 0, len, 0);
224 if (cloned == len)
225 goto out;
226
227
228
229 if (old_file->f_mode & FMODE_LSEEK &&
230 old_file->f_op->llseek)
231 skip_hole = true;
232
233 while (len) {
234 size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
235 long bytes;
236
237 if (len < this_len)
238 this_len = len;
239
240 if (signal_pending_state(TASK_KILLABLE, current)) {
241 error = -EINTR;
242 break;
243 }
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261 if (skip_hole && data_pos < old_pos) {
262 data_pos = vfs_llseek(old_file, old_pos, SEEK_DATA);
263 if (data_pos > old_pos) {
264 hole_len = data_pos - old_pos;
265 len -= hole_len;
266 old_pos = new_pos = data_pos;
267 continue;
268 } else if (data_pos == -ENXIO) {
269 break;
270 } else if (data_pos < 0) {
271 skip_hole = false;
272 }
273 }
274
275 bytes = do_splice_direct(old_file, &old_pos,
276 new_file, &new_pos,
277 this_len, SPLICE_F_MOVE);
278 if (bytes <= 0) {
279 error = bytes;
280 break;
281 }
282 WARN_ON(old_pos != new_pos);
283
284 len -= bytes;
285 }
286out:
287 if (!error && ovl_should_sync(ofs))
288 error = vfs_fsync(new_file, 0);
289 fput(new_file);
290out_fput:
291 fput(old_file);
292 return error;
293}
294
295static int ovl_set_size(struct dentry *upperdentry, struct kstat *stat)
296{
297 struct iattr attr = {
298 .ia_valid = ATTR_SIZE,
299 .ia_size = stat->size,
300 };
301
302 return notify_change(&init_user_ns, upperdentry, &attr, NULL);
303}
304
305static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat)
306{
307 struct iattr attr = {
308 .ia_valid =
309 ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET,
310 .ia_atime = stat->atime,
311 .ia_mtime = stat->mtime,
312 };
313
314 return notify_change(&init_user_ns, upperdentry, &attr, NULL);
315}
316
317int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat)
318{
319 int err = 0;
320
321 if (!S_ISLNK(stat->mode)) {
322 struct iattr attr = {
323 .ia_valid = ATTR_MODE,
324 .ia_mode = stat->mode,
325 };
326 err = notify_change(&init_user_ns, upperdentry, &attr, NULL);
327 }
328 if (!err) {
329 struct iattr attr = {
330 .ia_valid = ATTR_UID | ATTR_GID,
331 .ia_uid = stat->uid,
332 .ia_gid = stat->gid,
333 };
334 err = notify_change(&init_user_ns, upperdentry, &attr, NULL);
335 }
336 if (!err)
337 ovl_set_timestamps(upperdentry, stat);
338
339 return err;
340}
341
342struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
343 bool is_upper)
344{
345 struct ovl_fh *fh;
346 int fh_type, dwords;
347 int buflen = MAX_HANDLE_SZ;
348 uuid_t *uuid = &real->d_sb->s_uuid;
349 int err;
350
351
352 BUILD_BUG_ON(OVL_FH_FID_OFFSET % 4);
353 BUILD_BUG_ON(MAX_HANDLE_SZ + OVL_FH_FID_OFFSET > 255);
354
355 fh = kzalloc(buflen + OVL_FH_FID_OFFSET, GFP_KERNEL);
356 if (!fh)
357 return ERR_PTR(-ENOMEM);
358
359
360
361
362
363
364 dwords = buflen >> 2;
365 fh_type = exportfs_encode_fh(real, (void *)fh->fb.fid, &dwords, 0);
366 buflen = (dwords << 2);
367
368 err = -EIO;
369 if (WARN_ON(fh_type < 0) ||
370 WARN_ON(buflen > MAX_HANDLE_SZ) ||
371 WARN_ON(fh_type == FILEID_INVALID))
372 goto out_err;
373
374 fh->fb.version = OVL_FH_VERSION;
375 fh->fb.magic = OVL_FH_MAGIC;
376 fh->fb.type = fh_type;
377 fh->fb.flags = OVL_FH_FLAG_CPU_ENDIAN;
378
379
380
381
382
383
384 if (is_upper)
385 fh->fb.flags |= OVL_FH_FLAG_PATH_UPPER;
386 fh->fb.len = sizeof(fh->fb) + buflen;
387 if (ofs->config.uuid)
388 fh->fb.uuid = *uuid;
389
390 return fh;
391
392out_err:
393 kfree(fh);
394 return ERR_PTR(err);
395}
396
397int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower,
398 struct dentry *upper)
399{
400 const struct ovl_fh *fh = NULL;
401 int err;
402
403
404
405
406
407
408 if (ovl_can_decode_fh(lower->d_sb)) {
409 fh = ovl_encode_real_fh(ofs, lower, false);
410 if (IS_ERR(fh))
411 return PTR_ERR(fh);
412 }
413
414
415
416
417 err = ovl_check_setxattr(ofs, upper, OVL_XATTR_ORIGIN, fh->buf,
418 fh ? fh->fb.len : 0, 0);
419 kfree(fh);
420
421
422 return err == -EPERM ? 0 : err;
423}
424
425
426static int ovl_set_upper_fh(struct ovl_fs *ofs, struct dentry *upper,
427 struct dentry *index)
428{
429 const struct ovl_fh *fh;
430 int err;
431
432 fh = ovl_encode_real_fh(ofs, upper, true);
433 if (IS_ERR(fh))
434 return PTR_ERR(fh);
435
436 err = ovl_do_setxattr(ofs, index, OVL_XATTR_UPPER, fh->buf, fh->fb.len);
437
438 kfree(fh);
439 return err;
440}
441
442
443
444
445
446
447static int ovl_create_index(struct dentry *dentry, struct dentry *origin,
448 struct dentry *upper)
449{
450 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
451 struct dentry *indexdir = ovl_indexdir(dentry->d_sb);
452 struct inode *dir = d_inode(indexdir);
453 struct dentry *index = NULL;
454 struct dentry *temp = NULL;
455 struct qstr name = { };
456 int err;
457
458
459
460
461
462
463
464
465
466 if (WARN_ON(!d_is_dir(dentry)))
467 return -EIO;
468
469
470 if (WARN_ON(ovl_test_flag(OVL_INDEX, d_inode(dentry))))
471 return -EIO;
472
473 err = ovl_get_index_name(ofs, origin, &name);
474 if (err)
475 return err;
476
477 temp = ovl_create_temp(indexdir, OVL_CATTR(S_IFDIR | 0));
478 err = PTR_ERR(temp);
479 if (IS_ERR(temp))
480 goto free_name;
481
482 err = ovl_set_upper_fh(ofs, upper, temp);
483 if (err)
484 goto out;
485
486 index = lookup_one_len(name.name, indexdir, name.len);
487 if (IS_ERR(index)) {
488 err = PTR_ERR(index);
489 } else {
490 err = ovl_do_rename(dir, temp, dir, index, 0);
491 dput(index);
492 }
493out:
494 if (err)
495 ovl_cleanup(dir, temp);
496 dput(temp);
497free_name:
498 kfree(name.name);
499 return err;
500}
501
502struct ovl_copy_up_ctx {
503 struct dentry *parent;
504 struct dentry *dentry;
505 struct path lowerpath;
506 struct kstat stat;
507 struct kstat pstat;
508 const char *link;
509 struct dentry *destdir;
510 struct qstr destname;
511 struct dentry *workdir;
512 bool origin;
513 bool indexed;
514 bool metacopy;
515};
516
517static int ovl_link_up(struct ovl_copy_up_ctx *c)
518{
519 int err;
520 struct dentry *upper;
521 struct dentry *upperdir = ovl_dentry_upper(c->parent);
522 struct inode *udir = d_inode(upperdir);
523
524
525 err = ovl_set_impure(c->parent, upperdir);
526 if (err)
527 return err;
528
529 err = ovl_set_nlink_lower(c->dentry);
530 if (err)
531 return err;
532
533 inode_lock_nested(udir, I_MUTEX_PARENT);
534 upper = lookup_one_len(c->dentry->d_name.name, upperdir,
535 c->dentry->d_name.len);
536 err = PTR_ERR(upper);
537 if (!IS_ERR(upper)) {
538 err = ovl_do_link(ovl_dentry_upper(c->dentry), udir, upper);
539 dput(upper);
540
541 if (!err) {
542
543 ovl_set_timestamps(upperdir, &c->pstat);
544 ovl_dentry_set_upper_alias(c->dentry);
545 }
546 }
547 inode_unlock(udir);
548 if (err)
549 return err;
550
551 err = ovl_set_nlink_upper(c->dentry);
552
553 return err;
554}
555
556static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
557{
558 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
559 struct inode *inode = d_inode(c->dentry);
560 struct path upperpath, datapath;
561 int err;
562
563 ovl_path_upper(c->dentry, &upperpath);
564 if (WARN_ON(upperpath.dentry != NULL))
565 return -EIO;
566
567 upperpath.dentry = temp;
568
569
570
571
572
573 if (S_ISREG(c->stat.mode) && !c->metacopy) {
574 ovl_path_lowerdata(c->dentry, &datapath);
575 err = ovl_copy_up_data(ofs, &datapath, &upperpath,
576 c->stat.size);
577 if (err)
578 return err;
579 }
580
581 err = ovl_copy_xattr(c->dentry->d_sb, c->lowerpath.dentry, temp);
582 if (err)
583 return err;
584
585 if (inode->i_flags & OVL_COPY_I_FLAGS_MASK) {
586
587
588
589
590 err = ovl_copy_fileattr(inode, &c->lowerpath, &upperpath);
591 if (err)
592 return err;
593 }
594
595
596
597
598
599
600
601
602 if (c->origin) {
603 err = ovl_set_origin(ofs, c->lowerpath.dentry, temp);
604 if (err)
605 return err;
606 }
607
608 if (c->metacopy) {
609 err = ovl_check_setxattr(ofs, temp, OVL_XATTR_METACOPY,
610 NULL, 0, -EOPNOTSUPP);
611 if (err)
612 return err;
613 }
614
615 inode_lock(temp->d_inode);
616 if (S_ISREG(c->stat.mode))
617 err = ovl_set_size(temp, &c->stat);
618 if (!err)
619 err = ovl_set_attr(temp, &c->stat);
620 inode_unlock(temp->d_inode);
621
622 return err;
623}
624
625struct ovl_cu_creds {
626 const struct cred *old;
627 struct cred *new;
628};
629
630static int ovl_prep_cu_creds(struct dentry *dentry, struct ovl_cu_creds *cc)
631{
632 int err;
633
634 cc->old = cc->new = NULL;
635 err = security_inode_copy_up(dentry, &cc->new);
636 if (err < 0)
637 return err;
638
639 if (cc->new)
640 cc->old = override_creds(cc->new);
641
642 return 0;
643}
644
645static void ovl_revert_cu_creds(struct ovl_cu_creds *cc)
646{
647 if (cc->new) {
648 revert_creds(cc->old);
649 put_cred(cc->new);
650 }
651}
652
653
654
655
656
657static int ovl_copy_up_workdir(struct ovl_copy_up_ctx *c)
658{
659 struct inode *inode;
660 struct inode *udir = d_inode(c->destdir), *wdir = d_inode(c->workdir);
661 struct dentry *temp, *upper;
662 struct ovl_cu_creds cc;
663 int err;
664 struct ovl_cattr cattr = {
665
666 .mode = c->stat.mode & S_IFMT,
667 .rdev = c->stat.rdev,
668 .link = c->link
669 };
670
671
672 err = -EIO;
673 if (lock_rename(c->workdir, c->destdir) != NULL)
674 goto unlock;
675
676 err = ovl_prep_cu_creds(c->dentry, &cc);
677 if (err)
678 goto unlock;
679
680 temp = ovl_create_temp(c->workdir, &cattr);
681 ovl_revert_cu_creds(&cc);
682
683 err = PTR_ERR(temp);
684 if (IS_ERR(temp))
685 goto unlock;
686
687 err = ovl_copy_up_inode(c, temp);
688 if (err)
689 goto cleanup;
690
691 if (S_ISDIR(c->stat.mode) && c->indexed) {
692 err = ovl_create_index(c->dentry, c->lowerpath.dentry, temp);
693 if (err)
694 goto cleanup;
695 }
696
697 upper = lookup_one_len(c->destname.name, c->destdir, c->destname.len);
698 err = PTR_ERR(upper);
699 if (IS_ERR(upper))
700 goto cleanup;
701
702 err = ovl_do_rename(wdir, temp, udir, upper, 0);
703 dput(upper);
704 if (err)
705 goto cleanup;
706
707 if (!c->metacopy)
708 ovl_set_upperdata(d_inode(c->dentry));
709 inode = d_inode(c->dentry);
710 ovl_inode_update(inode, temp);
711 if (S_ISDIR(inode->i_mode))
712 ovl_set_flag(OVL_WHITEOUTS, inode);
713unlock:
714 unlock_rename(c->workdir, c->destdir);
715
716 return err;
717
718cleanup:
719 ovl_cleanup(wdir, temp);
720 dput(temp);
721 goto unlock;
722}
723
724
725static int ovl_copy_up_tmpfile(struct ovl_copy_up_ctx *c)
726{
727 struct inode *udir = d_inode(c->destdir);
728 struct dentry *temp, *upper;
729 struct ovl_cu_creds cc;
730 int err;
731
732 err = ovl_prep_cu_creds(c->dentry, &cc);
733 if (err)
734 return err;
735
736 temp = ovl_do_tmpfile(c->workdir, c->stat.mode);
737 ovl_revert_cu_creds(&cc);
738
739 if (IS_ERR(temp))
740 return PTR_ERR(temp);
741
742 err = ovl_copy_up_inode(c, temp);
743 if (err)
744 goto out_dput;
745
746 inode_lock_nested(udir, I_MUTEX_PARENT);
747
748 upper = lookup_one_len(c->destname.name, c->destdir, c->destname.len);
749 err = PTR_ERR(upper);
750 if (!IS_ERR(upper)) {
751 err = ovl_do_link(temp, udir, upper);
752 dput(upper);
753 }
754 inode_unlock(udir);
755
756 if (err)
757 goto out_dput;
758
759 if (!c->metacopy)
760 ovl_set_upperdata(d_inode(c->dentry));
761 ovl_inode_update(d_inode(c->dentry), temp);
762
763 return 0;
764
765out_dput:
766 dput(temp);
767 return err;
768}
769
770
771
772
773
774
775
776
777
778
779static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
780{
781 int err;
782 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
783 bool to_index = false;
784
785
786
787
788
789
790
791 if (ovl_need_index(c->dentry)) {
792 c->indexed = true;
793 if (S_ISDIR(c->stat.mode))
794 c->workdir = ovl_indexdir(c->dentry->d_sb);
795 else
796 to_index = true;
797 }
798
799 if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || to_index)
800 c->origin = true;
801
802 if (to_index) {
803 c->destdir = ovl_indexdir(c->dentry->d_sb);
804 err = ovl_get_index_name(ofs, c->lowerpath.dentry, &c->destname);
805 if (err)
806 return err;
807 } else if (WARN_ON(!c->parent)) {
808
809 return -EIO;
810 } else {
811
812
813
814
815 err = ovl_set_impure(c->parent, c->destdir);
816 if (err)
817 return err;
818 }
819
820
821 if (S_ISREG(c->stat.mode) && ofs->tmpfile)
822 err = ovl_copy_up_tmpfile(c);
823 else
824 err = ovl_copy_up_workdir(c);
825 if (err)
826 goto out;
827
828 if (c->indexed)
829 ovl_set_flag(OVL_INDEX, d_inode(c->dentry));
830
831 if (to_index) {
832
833 err = ovl_set_nlink_upper(c->dentry);
834 } else {
835 struct inode *udir = d_inode(c->destdir);
836
837
838 inode_lock(udir);
839 ovl_set_timestamps(c->destdir, &c->pstat);
840 inode_unlock(udir);
841
842 ovl_dentry_set_upper_alias(c->dentry);
843 }
844
845out:
846 if (to_index)
847 kfree(c->destname.name);
848 return err;
849}
850
851static bool ovl_need_meta_copy_up(struct dentry *dentry, umode_t mode,
852 int flags)
853{
854 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
855
856 if (!ofs->config.metacopy)
857 return false;
858
859 if (!S_ISREG(mode))
860 return false;
861
862 if (flags && ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)))
863 return false;
864
865 return true;
866}
867
868static ssize_t ovl_getxattr(struct dentry *dentry, char *name, char **value)
869{
870 ssize_t res;
871 char *buf;
872
873 res = vfs_getxattr(&init_user_ns, dentry, name, NULL, 0);
874 if (res == -ENODATA || res == -EOPNOTSUPP)
875 res = 0;
876
877 if (res > 0) {
878 buf = kzalloc(res, GFP_KERNEL);
879 if (!buf)
880 return -ENOMEM;
881
882 res = vfs_getxattr(&init_user_ns, dentry, name, buf, res);
883 if (res < 0)
884 kfree(buf);
885 else
886 *value = buf;
887 }
888 return res;
889}
890
891
892static int ovl_copy_up_meta_inode_data(struct ovl_copy_up_ctx *c)
893{
894 struct ovl_fs *ofs = OVL_FS(c->dentry->d_sb);
895 struct path upperpath, datapath;
896 int err;
897 char *capability = NULL;
898 ssize_t cap_size;
899
900 ovl_path_upper(c->dentry, &upperpath);
901 if (WARN_ON(upperpath.dentry == NULL))
902 return -EIO;
903
904 ovl_path_lowerdata(c->dentry, &datapath);
905 if (WARN_ON(datapath.dentry == NULL))
906 return -EIO;
907
908 if (c->stat.size) {
909 err = cap_size = ovl_getxattr(upperpath.dentry, XATTR_NAME_CAPS,
910 &capability);
911 if (cap_size < 0)
912 goto out;
913 }
914
915 err = ovl_copy_up_data(ofs, &datapath, &upperpath, c->stat.size);
916 if (err)
917 goto out_free;
918
919
920
921
922
923 if (capability) {
924 err = vfs_setxattr(&init_user_ns, upperpath.dentry,
925 XATTR_NAME_CAPS, capability, cap_size, 0);
926 if (err)
927 goto out_free;
928 }
929
930
931 err = ovl_do_removexattr(ofs, upperpath.dentry, OVL_XATTR_METACOPY);
932 if (err)
933 goto out_free;
934
935 ovl_set_upperdata(d_inode(c->dentry));
936out_free:
937 kfree(capability);
938out:
939 return err;
940}
941
942static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
943 int flags)
944{
945 int err;
946 DEFINE_DELAYED_CALL(done);
947 struct path parentpath;
948 struct ovl_copy_up_ctx ctx = {
949 .parent = parent,
950 .dentry = dentry,
951 .workdir = ovl_workdir(dentry),
952 };
953
954 if (WARN_ON(!ctx.workdir))
955 return -EROFS;
956
957 ovl_path_lower(dentry, &ctx.lowerpath);
958 err = vfs_getattr(&ctx.lowerpath, &ctx.stat,
959 STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
960 if (err)
961 return err;
962
963 ctx.metacopy = ovl_need_meta_copy_up(dentry, ctx.stat.mode, flags);
964
965 if (parent) {
966 ovl_path_upper(parent, &parentpath);
967 ctx.destdir = parentpath.dentry;
968 ctx.destname = dentry->d_name;
969
970 err = vfs_getattr(&parentpath, &ctx.pstat,
971 STATX_ATIME | STATX_MTIME,
972 AT_STATX_SYNC_AS_STAT);
973 if (err)
974 return err;
975 }
976
977
978 if (flags & O_TRUNC)
979 ctx.stat.size = 0;
980
981 if (S_ISLNK(ctx.stat.mode)) {
982 ctx.link = vfs_get_link(ctx.lowerpath.dentry, &done);
983 if (IS_ERR(ctx.link))
984 return PTR_ERR(ctx.link);
985 }
986
987 err = ovl_copy_up_start(dentry, flags);
988
989 if (unlikely(err)) {
990 if (err > 0)
991 err = 0;
992 } else {
993 if (!ovl_dentry_upper(dentry))
994 err = ovl_do_copy_up(&ctx);
995 if (!err && parent && !ovl_dentry_has_upper_alias(dentry))
996 err = ovl_link_up(&ctx);
997 if (!err && ovl_dentry_needs_data_copy_up_locked(dentry, flags))
998 err = ovl_copy_up_meta_inode_data(&ctx);
999 ovl_copy_up_end(dentry);
1000 }
1001 do_delayed_call(&done);
1002
1003 return err;
1004}
1005
1006static int ovl_copy_up_flags(struct dentry *dentry, int flags)
1007{
1008 int err = 0;
1009 const struct cred *old_cred;
1010 bool disconnected = (dentry->d_flags & DCACHE_DISCONNECTED);
1011
1012
1013
1014
1015
1016
1017 if (WARN_ON(disconnected && d_is_dir(dentry)))
1018 return -EIO;
1019
1020 old_cred = ovl_override_creds(dentry->d_sb);
1021 while (!err) {
1022 struct dentry *next;
1023 struct dentry *parent = NULL;
1024
1025 if (ovl_already_copied_up(dentry, flags))
1026 break;
1027
1028 next = dget(dentry);
1029
1030 for (; !disconnected;) {
1031 parent = dget_parent(next);
1032
1033 if (ovl_dentry_upper(parent))
1034 break;
1035
1036 dput(next);
1037 next = parent;
1038 }
1039
1040 err = ovl_copy_up_one(parent, next, flags);
1041
1042 dput(parent);
1043 dput(next);
1044 }
1045 revert_creds(old_cred);
1046
1047 return err;
1048}
1049
1050static bool ovl_open_need_copy_up(struct dentry *dentry, int flags)
1051{
1052
1053 if (ovl_already_copied_up(dentry, flags))
1054 return false;
1055
1056 if (special_file(d_inode(dentry)->i_mode))
1057 return false;
1058
1059 if (!ovl_open_flags_need_copy_up(flags))
1060 return false;
1061
1062 return true;
1063}
1064
1065int ovl_maybe_copy_up(struct dentry *dentry, int flags)
1066{
1067 int err = 0;
1068
1069 if (ovl_open_need_copy_up(dentry, flags)) {
1070 err = ovl_want_write(dentry);
1071 if (!err) {
1072 err = ovl_copy_up_flags(dentry, flags);
1073 ovl_drop_write(dentry);
1074 }
1075 }
1076
1077 return err;
1078}
1079
1080int ovl_copy_up_with_data(struct dentry *dentry)
1081{
1082 return ovl_copy_up_flags(dentry, O_WRONLY);
1083}
1084
1085int ovl_copy_up(struct dentry *dentry)
1086{
1087 return ovl_copy_up_flags(dentry, 0);
1088}
1089