1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 *
4 * Copyright (C) 2011 Novell Inc.
5 */
6
7 #include <linux/fs.h>
8 #include <linux/namei.h>
9 #include <linux/xattr.h>
10 #include <linux/security.h>
11 #include <linux/cred.h>
12 #include <linux/module.h>
13 #include <linux/posix_acl.h>
14 #include <linux/posix_acl_xattr.h>
15 #include <linux/atomic.h>
16 #include <linux/ratelimit.h>
17 #include <linux/backing-file.h>
18 #include "overlayfs.h"
19
20 static unsigned short ovl_redirect_max = 256;
21 module_param_named(redirect_max, ovl_redirect_max, ushort, 0644);
22 MODULE_PARM_DESC(redirect_max,
23 "Maximum length of absolute redirect xattr value");
24
25 static int ovl_set_redirect(struct dentry *dentry, bool samedir);
26
ovl_cleanup(struct ovl_fs * ofs,struct inode * wdir,struct dentry * wdentry)27 int ovl_cleanup(struct ovl_fs *ofs, struct inode *wdir, struct dentry *wdentry)
28 {
29 int err;
30
31 dget(wdentry);
32 if (d_is_dir(wdentry))
33 err = ovl_do_rmdir(ofs, wdir, wdentry);
34 else
35 err = ovl_do_unlink(ofs, wdir, wdentry);
36 dput(wdentry);
37
38 if (err) {
39 pr_err("cleanup of '%pd2' failed (%i)\n",
40 wdentry, err);
41 }
42
43 return err;
44 }
45
ovl_lookup_temp(struct ovl_fs * ofs,struct dentry * workdir)46 struct dentry *ovl_lookup_temp(struct ovl_fs *ofs, struct dentry *workdir)
47 {
48 struct dentry *temp;
49 char name[20];
50 static atomic_t temp_id = ATOMIC_INIT(0);
51
52 /* counter is allowed to wrap, since temp dentries are ephemeral */
53 snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id));
54
55 temp = ovl_lookup_upper(ofs, name, workdir, strlen(name));
56 if (!IS_ERR(temp) && temp->d_inode) {
57 pr_err("workdir/%s already exists\n", name);
58 dput(temp);
59 temp = ERR_PTR(-EIO);
60 }
61
62 return temp;
63 }
64
65 /* caller holds i_mutex on workdir */
ovl_whiteout(struct ovl_fs * ofs)66 static struct dentry *ovl_whiteout(struct ovl_fs *ofs)
67 {
68 int err;
69 struct dentry *whiteout;
70 struct dentry *workdir = ofs->workdir;
71 struct inode *wdir = workdir->d_inode;
72
73 if (!ofs->whiteout) {
74 whiteout = ovl_lookup_temp(ofs, workdir);
75 if (IS_ERR(whiteout))
76 goto out;
77
78 err = ovl_do_whiteout(ofs, wdir, whiteout);
79 if (err) {
80 dput(whiteout);
81 whiteout = ERR_PTR(err);
82 goto out;
83 }
84 ofs->whiteout = whiteout;
85 }
86
87 if (!ofs->no_shared_whiteout) {
88 whiteout = ovl_lookup_temp(ofs, workdir);
89 if (IS_ERR(whiteout))
90 goto out;
91
92 err = ovl_do_link(ofs, ofs->whiteout, wdir, whiteout);
93 if (!err)
94 goto out;
95
96 if (err != -EMLINK) {
97 pr_warn("Failed to link whiteout - disabling whiteout inode sharing(nlink=%u, err=%i)\n",
98 ofs->whiteout->d_inode->i_nlink, err);
99 ofs->no_shared_whiteout = true;
100 }
101 dput(whiteout);
102 }
103 whiteout = ofs->whiteout;
104 ofs->whiteout = NULL;
105 out:
106 return whiteout;
107 }
108
109 /* Caller must hold i_mutex on both workdir and dir */
ovl_cleanup_and_whiteout(struct ovl_fs * ofs,struct inode * dir,struct dentry * dentry)110 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
111 struct dentry *dentry)
112 {
113 struct inode *wdir = ofs->workdir->d_inode;
114 struct dentry *whiteout;
115 int err;
116 int flags = 0;
117
118 whiteout = ovl_whiteout(ofs);
119 err = PTR_ERR(whiteout);
120 if (IS_ERR(whiteout))
121 return err;
122
123 if (d_is_dir(dentry))
124 flags = RENAME_EXCHANGE;
125
126 err = ovl_do_rename(ofs, wdir, whiteout, dir, dentry, flags);
127 if (err)
128 goto kill_whiteout;
129 if (flags)
130 ovl_cleanup(ofs, wdir, dentry);
131
132 out:
133 dput(whiteout);
134 return err;
135
136 kill_whiteout:
137 ovl_cleanup(ofs, wdir, whiteout);
138 goto out;
139 }
140
ovl_create_real(struct ovl_fs * ofs,struct inode * dir,struct dentry * newdentry,struct ovl_cattr * attr)141 struct dentry *ovl_create_real(struct ovl_fs *ofs, struct inode *dir,
142 struct dentry *newdentry, struct ovl_cattr *attr)
143 {
144 int err;
145
146 if (IS_ERR(newdentry))
147 return newdentry;
148
149 err = -ESTALE;
150 if (newdentry->d_inode)
151 goto out;
152
153 if (attr->hardlink) {
154 err = ovl_do_link(ofs, attr->hardlink, dir, newdentry);
155 } else {
156 switch (attr->mode & S_IFMT) {
157 case S_IFREG:
158 err = ovl_do_create(ofs, dir, newdentry, attr->mode);
159 break;
160
161 case S_IFDIR:
162 /* mkdir is special... */
163 newdentry = ovl_do_mkdir(ofs, dir, newdentry, attr->mode);
164 err = PTR_ERR_OR_ZERO(newdentry);
165 break;
166
167 case S_IFCHR:
168 case S_IFBLK:
169 case S_IFIFO:
170 case S_IFSOCK:
171 err = ovl_do_mknod(ofs, dir, newdentry, attr->mode,
172 attr->rdev);
173 break;
174
175 case S_IFLNK:
176 err = ovl_do_symlink(ofs, dir, newdentry, attr->link);
177 break;
178
179 default:
180 err = -EPERM;
181 }
182 }
183 if (!err && WARN_ON(!newdentry->d_inode)) {
184 /*
185 * Not quite sure if non-instantiated dentry is legal or not.
186 * VFS doesn't seem to care so check and warn here.
187 */
188 err = -EIO;
189 }
190 out:
191 if (err) {
192 if (!IS_ERR(newdentry))
193 dput(newdentry);
194 return ERR_PTR(err);
195 }
196 return newdentry;
197 }
198
ovl_create_temp(struct ovl_fs * ofs,struct dentry * workdir,struct ovl_cattr * attr)199 struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir,
200 struct ovl_cattr *attr)
201 {
202 return ovl_create_real(ofs, d_inode(workdir),
203 ovl_lookup_temp(ofs, workdir), attr);
204 }
205
ovl_set_opaque_xerr(struct dentry * dentry,struct dentry * upper,int xerr)206 static int ovl_set_opaque_xerr(struct dentry *dentry, struct dentry *upper,
207 int xerr)
208 {
209 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
210 int err;
211
212 err = ovl_check_setxattr(ofs, upper, OVL_XATTR_OPAQUE, "y", 1, xerr);
213 if (!err)
214 ovl_dentry_set_opaque(dentry);
215
216 return err;
217 }
218
ovl_set_opaque(struct dentry * dentry,struct dentry * upperdentry)219 static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry)
220 {
221 /*
222 * Fail with -EIO when trying to create opaque dir and upper doesn't
223 * support xattrs. ovl_rename() calls ovl_set_opaque_xerr(-EXDEV) to
224 * return a specific error for noxattr case.
225 */
226 return ovl_set_opaque_xerr(dentry, upperdentry, -EIO);
227 }
228
229 /*
230 * Common operations required to be done after creation of file on upper.
231 * If @hardlink is false, then @inode is a pre-allocated inode, we may or
232 * may not use to instantiate the new dentry.
233 */
ovl_instantiate(struct dentry * dentry,struct inode * inode,struct dentry * newdentry,bool hardlink,struct file * tmpfile)234 static int ovl_instantiate(struct dentry *dentry, struct inode *inode,
235 struct dentry *newdentry, bool hardlink, struct file *tmpfile)
236 {
237 struct ovl_inode_params oip = {
238 .upperdentry = newdentry,
239 .newinode = inode,
240 };
241
242 ovl_dentry_set_upper_alias(dentry);
243 ovl_dentry_init_reval(dentry, newdentry, NULL);
244
245 if (!hardlink) {
246 /*
247 * ovl_obtain_alias() can be called after ovl_create_real()
248 * and before we get here, so we may get an inode from cache
249 * with the same real upperdentry that is not the inode we
250 * pre-allocated. In this case we will use the cached inode
251 * to instantiate the new dentry.
252 *
253 * XXX: if we ever use ovl_obtain_alias() to decode directory
254 * file handles, need to use ovl_get_inode_locked() and
255 * d_instantiate_new() here to prevent from creating two
256 * hashed directory inode aliases. We then need to return
257 * the obtained alias to ovl_mkdir().
258 */
259 inode = ovl_get_inode(dentry->d_sb, &oip);
260 if (IS_ERR(inode))
261 return PTR_ERR(inode);
262 if (inode == oip.newinode)
263 ovl_set_flag(OVL_UPPERDATA, inode);
264 } else {
265 WARN_ON(ovl_inode_real(inode) != d_inode(newdentry));
266 dput(newdentry);
267 inc_nlink(inode);
268 }
269
270 if (tmpfile)
271 d_mark_tmpfile(tmpfile, inode);
272
273 d_instantiate(dentry, inode);
274 if (inode != oip.newinode) {
275 pr_warn_ratelimited("newly created inode found in cache (%pd2)\n",
276 dentry);
277 }
278
279 /* Force lookup of new upper hardlink to find its lower */
280 if (hardlink)
281 d_drop(dentry);
282
283 return 0;
284 }
285
ovl_type_merge(struct dentry * dentry)286 static bool ovl_type_merge(struct dentry *dentry)
287 {
288 return OVL_TYPE_MERGE(ovl_path_type(dentry));
289 }
290
ovl_type_origin(struct dentry * dentry)291 static bool ovl_type_origin(struct dentry *dentry)
292 {
293 return OVL_TYPE_ORIGIN(ovl_path_type(dentry));
294 }
295
ovl_create_upper(struct dentry * dentry,struct inode * inode,struct ovl_cattr * attr)296 static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
297 struct ovl_cattr *attr)
298 {
299 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
300 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
301 struct inode *udir = upperdir->d_inode;
302 struct dentry *newdentry;
303 int err;
304
305 inode_lock_nested(udir, I_MUTEX_PARENT);
306 newdentry = ovl_create_real(ofs, udir,
307 ovl_lookup_upper(ofs, dentry->d_name.name,
308 upperdir, dentry->d_name.len),
309 attr);
310 err = PTR_ERR(newdentry);
311 if (IS_ERR(newdentry))
312 goto out_unlock;
313
314 if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry) &&
315 !ovl_allow_offline_changes(ofs)) {
316 /* Setting opaque here is just an optimization, allow to fail */
317 ovl_set_opaque(dentry, newdentry);
318 }
319
320 ovl_dir_modified(dentry->d_parent, false);
321 err = ovl_instantiate(dentry, inode, newdentry, !!attr->hardlink, NULL);
322 if (err)
323 goto out_cleanup;
324 out_unlock:
325 inode_unlock(udir);
326 return err;
327
328 out_cleanup:
329 ovl_cleanup(ofs, udir, newdentry);
330 dput(newdentry);
331 goto out_unlock;
332 }
333
ovl_clear_empty(struct dentry * dentry,struct list_head * list)334 static struct dentry *ovl_clear_empty(struct dentry *dentry,
335 struct list_head *list)
336 {
337 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
338 struct dentry *workdir = ovl_workdir(dentry);
339 struct inode *wdir = workdir->d_inode;
340 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
341 struct inode *udir = upperdir->d_inode;
342 struct path upperpath;
343 struct dentry *upper;
344 struct dentry *opaquedir;
345 struct kstat stat;
346 int err;
347
348 if (WARN_ON(!workdir))
349 return ERR_PTR(-EROFS);
350
351 err = ovl_lock_rename_workdir(workdir, upperdir);
352 if (err)
353 goto out;
354
355 ovl_path_upper(dentry, &upperpath);
356 err = vfs_getattr(&upperpath, &stat,
357 STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT);
358 if (err)
359 goto out_unlock;
360
361 err = -ESTALE;
362 if (!S_ISDIR(stat.mode))
363 goto out_unlock;
364 upper = upperpath.dentry;
365 if (upper->d_parent->d_inode != udir)
366 goto out_unlock;
367
368 opaquedir = ovl_create_temp(ofs, workdir, OVL_CATTR(stat.mode));
369 err = PTR_ERR(opaquedir);
370 if (IS_ERR(opaquedir))
371 goto out_unlock;
372
373 err = ovl_copy_xattr(dentry->d_sb, &upperpath, opaquedir);
374 if (err)
375 goto out_cleanup;
376
377 err = ovl_set_opaque(dentry, opaquedir);
378 if (err)
379 goto out_cleanup;
380
381 inode_lock(opaquedir->d_inode);
382 err = ovl_set_attr(ofs, opaquedir, &stat);
383 inode_unlock(opaquedir->d_inode);
384 if (err)
385 goto out_cleanup;
386
387 err = ovl_do_rename(ofs, wdir, opaquedir, udir, upper, RENAME_EXCHANGE);
388 if (err)
389 goto out_cleanup;
390
391 ovl_cleanup_whiteouts(ofs, upper, list);
392 ovl_cleanup(ofs, wdir, upper);
393 unlock_rename(workdir, upperdir);
394
395 /* dentry's upper doesn't match now, get rid of it */
396 d_drop(dentry);
397
398 return opaquedir;
399
400 out_cleanup:
401 ovl_cleanup(ofs, wdir, opaquedir);
402 dput(opaquedir);
403 out_unlock:
404 unlock_rename(workdir, upperdir);
405 out:
406 return ERR_PTR(err);
407 }
408
ovl_set_upper_acl(struct ovl_fs * ofs,struct dentry * upperdentry,const char * acl_name,struct posix_acl * acl)409 static int ovl_set_upper_acl(struct ovl_fs *ofs, struct dentry *upperdentry,
410 const char *acl_name, struct posix_acl *acl)
411 {
412 if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl)
413 return 0;
414
415 return ovl_do_set_acl(ofs, upperdentry, acl_name, acl);
416 }
417
ovl_create_over_whiteout(struct dentry * dentry,struct inode * inode,struct ovl_cattr * cattr)418 static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
419 struct ovl_cattr *cattr)
420 {
421 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
422 struct dentry *workdir = ovl_workdir(dentry);
423 struct inode *wdir = workdir->d_inode;
424 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
425 struct inode *udir = upperdir->d_inode;
426 struct dentry *upper;
427 struct dentry *newdentry;
428 int err;
429 struct posix_acl *acl, *default_acl;
430 bool hardlink = !!cattr->hardlink;
431
432 if (WARN_ON(!workdir))
433 return -EROFS;
434
435 if (!hardlink) {
436 err = posix_acl_create(dentry->d_parent->d_inode,
437 &cattr->mode, &default_acl, &acl);
438 if (err)
439 return err;
440 }
441
442 err = ovl_lock_rename_workdir(workdir, upperdir);
443 if (err)
444 goto out;
445
446 upper = ovl_lookup_upper(ofs, dentry->d_name.name, upperdir,
447 dentry->d_name.len);
448 err = PTR_ERR(upper);
449 if (IS_ERR(upper))
450 goto out_unlock;
451
452 err = -ESTALE;
453 if (d_is_negative(upper) || !ovl_upper_is_whiteout(ofs, upper))
454 goto out_dput;
455
456 newdentry = ovl_create_temp(ofs, workdir, cattr);
457 err = PTR_ERR(newdentry);
458 if (IS_ERR(newdentry))
459 goto out_dput;
460
461 /*
462 * mode could have been mutilated due to umask (e.g. sgid directory)
463 */
464 if (!hardlink &&
465 !S_ISLNK(cattr->mode) &&
466 newdentry->d_inode->i_mode != cattr->mode) {
467 struct iattr attr = {
468 .ia_valid = ATTR_MODE,
469 .ia_mode = cattr->mode,
470 };
471 inode_lock(newdentry->d_inode);
472 err = ovl_do_notify_change(ofs, newdentry, &attr);
473 inode_unlock(newdentry->d_inode);
474 if (err)
475 goto out_cleanup;
476 }
477 if (!hardlink) {
478 err = ovl_set_upper_acl(ofs, newdentry,
479 XATTR_NAME_POSIX_ACL_ACCESS, acl);
480 if (err)
481 goto out_cleanup;
482
483 err = ovl_set_upper_acl(ofs, newdentry,
484 XATTR_NAME_POSIX_ACL_DEFAULT, default_acl);
485 if (err)
486 goto out_cleanup;
487 }
488
489 if (!hardlink && S_ISDIR(cattr->mode)) {
490 err = ovl_set_opaque(dentry, newdentry);
491 if (err)
492 goto out_cleanup;
493
494 err = ovl_do_rename(ofs, wdir, newdentry, udir, upper,
495 RENAME_EXCHANGE);
496 if (err)
497 goto out_cleanup;
498
499 ovl_cleanup(ofs, wdir, upper);
500 } else {
501 err = ovl_do_rename(ofs, wdir, newdentry, udir, upper, 0);
502 if (err)
503 goto out_cleanup;
504 }
505 ovl_dir_modified(dentry->d_parent, false);
506 err = ovl_instantiate(dentry, inode, newdentry, hardlink, NULL);
507 if (err) {
508 ovl_cleanup(ofs, udir, newdentry);
509 dput(newdentry);
510 }
511 out_dput:
512 dput(upper);
513 out_unlock:
514 unlock_rename(workdir, upperdir);
515 out:
516 if (!hardlink) {
517 posix_acl_release(acl);
518 posix_acl_release(default_acl);
519 }
520 return err;
521
522 out_cleanup:
523 ovl_cleanup(ofs, wdir, newdentry);
524 dput(newdentry);
525 goto out_dput;
526 }
527
ovl_setup_cred_for_create(struct dentry * dentry,struct inode * inode,umode_t mode,const struct cred * old_cred)528 static const struct cred *ovl_setup_cred_for_create(struct dentry *dentry,
529 struct inode *inode,
530 umode_t mode,
531 const struct cred *old_cred)
532 {
533 int err;
534 struct cred *override_cred;
535
536 override_cred = prepare_creds();
537 if (!override_cred)
538 return ERR_PTR(-ENOMEM);
539
540 override_cred->fsuid = inode->i_uid;
541 override_cred->fsgid = inode->i_gid;
542 err = security_dentry_create_files_as(dentry, mode, &dentry->d_name,
543 old_cred, override_cred);
544 if (err) {
545 put_cred(override_cred);
546 return ERR_PTR(err);
547 }
548
549 /*
550 * Caller is going to match this with revert_creds() and drop
551 * referenec on the returned creds.
552 * We must be called with creator creds already, otherwise we risk
553 * leaking creds.
554 */
555 old_cred = override_creds(override_cred);
556 WARN_ON_ONCE(old_cred != ovl_creds(dentry->d_sb));
557
558 return override_cred;
559 }
560
ovl_create_or_link(struct dentry * dentry,struct inode * inode,struct ovl_cattr * attr,bool origin)561 static int ovl_create_or_link(struct dentry *dentry, struct inode *inode,
562 struct ovl_cattr *attr, bool origin)
563 {
564 int err;
565 const struct cred *old_cred, *new_cred = NULL;
566 struct dentry *parent = dentry->d_parent;
567
568 old_cred = ovl_override_creds(dentry->d_sb);
569
570 /*
571 * When linking a file with copy up origin into a new parent, mark the
572 * new parent dir "impure".
573 */
574 if (origin) {
575 err = ovl_set_impure(parent, ovl_dentry_upper(parent));
576 if (err)
577 goto out_revert_creds;
578 }
579
580 if (!attr->hardlink) {
581 /*
582 * In the creation cases(create, mkdir, mknod, symlink),
583 * ovl should transfer current's fs{u,g}id to underlying
584 * fs. Because underlying fs want to initialize its new
585 * inode owner using current's fs{u,g}id. And in this
586 * case, the @inode is a new inode that is initialized
587 * in inode_init_owner() to current's fs{u,g}id. So use
588 * the inode's i_{u,g}id to override the cred's fs{u,g}id.
589 *
590 * But in the other hardlink case, ovl_link() does not
591 * create a new inode, so just use the ovl mounter's
592 * fs{u,g}id.
593 */
594 new_cred = ovl_setup_cred_for_create(dentry, inode, attr->mode,
595 old_cred);
596 err = PTR_ERR(new_cred);
597 if (IS_ERR(new_cred)) {
598 new_cred = NULL;
599 goto out_revert_creds;
600 }
601 }
602
603 if (!ovl_dentry_is_whiteout(dentry))
604 err = ovl_create_upper(dentry, inode, attr);
605 else
606 err = ovl_create_over_whiteout(dentry, inode, attr);
607
608 out_revert_creds:
609 ovl_revert_creds(old_cred);
610 put_cred(new_cred);
611 return err;
612 }
613
ovl_create_object(struct dentry * dentry,int mode,dev_t rdev,const char * link)614 static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
615 const char *link)
616 {
617 int err;
618 struct inode *inode;
619 struct ovl_cattr attr = {
620 .rdev = rdev,
621 .link = link,
622 };
623
624 err = ovl_copy_up(dentry->d_parent);
625 if (err)
626 return err;
627
628 err = ovl_want_write(dentry);
629 if (err)
630 goto out;
631
632 /* Preallocate inode to be used by ovl_get_inode() */
633 err = -ENOMEM;
634 inode = ovl_new_inode(dentry->d_sb, mode, rdev);
635 if (!inode)
636 goto out_drop_write;
637
638 spin_lock(&inode->i_lock);
639 inode->i_state |= I_CREATING;
640 spin_unlock(&inode->i_lock);
641
642 inode_init_owner(&nop_mnt_idmap, inode, dentry->d_parent->d_inode, mode);
643 attr.mode = inode->i_mode;
644
645 err = ovl_create_or_link(dentry, inode, &attr, false);
646 /* Did we end up using the preallocated inode? */
647 if (inode != d_inode(dentry))
648 iput(inode);
649
650 out_drop_write:
651 ovl_drop_write(dentry);
652 out:
653 return err;
654 }
655
ovl_create(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)656 static int ovl_create(struct mnt_idmap *idmap, struct inode *dir,
657 struct dentry *dentry, umode_t mode, bool excl)
658 {
659 return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
660 }
661
ovl_mkdir(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode)662 static struct dentry *ovl_mkdir(struct mnt_idmap *idmap, struct inode *dir,
663 struct dentry *dentry, umode_t mode)
664 {
665 return ERR_PTR(ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL));
666 }
667
ovl_mknod(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,umode_t mode,dev_t rdev)668 static int ovl_mknod(struct mnt_idmap *idmap, struct inode *dir,
669 struct dentry *dentry, umode_t mode, dev_t rdev)
670 {
671 /* Don't allow creation of "whiteout" on overlay */
672 if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
673 return -EPERM;
674
675 return ovl_create_object(dentry, mode, rdev, NULL);
676 }
677
ovl_symlink(struct mnt_idmap * idmap,struct inode * dir,struct dentry * dentry,const char * link)678 static int ovl_symlink(struct mnt_idmap *idmap, struct inode *dir,
679 struct dentry *dentry, const char *link)
680 {
681 return ovl_create_object(dentry, S_IFLNK, 0, link);
682 }
683
ovl_set_link_redirect(struct dentry * dentry)684 static int ovl_set_link_redirect(struct dentry *dentry)
685 {
686 const struct cred *old_cred;
687 int err;
688
689 old_cred = ovl_override_creds(dentry->d_sb);
690 err = ovl_set_redirect(dentry, false);
691 ovl_revert_creds(old_cred);
692
693 return err;
694 }
695
ovl_link(struct dentry * old,struct inode * newdir,struct dentry * new)696 static int ovl_link(struct dentry *old, struct inode *newdir,
697 struct dentry *new)
698 {
699 int err;
700 struct inode *inode;
701
702 err = ovl_copy_up(old);
703 if (err)
704 goto out;
705
706 err = ovl_copy_up(new->d_parent);
707 if (err)
708 goto out;
709
710 err = ovl_nlink_start(old);
711 if (err)
712 goto out;
713
714 if (ovl_is_metacopy_dentry(old)) {
715 err = ovl_set_link_redirect(old);
716 if (err)
717 goto out_nlink_end;
718 }
719
720 inode = d_inode(old);
721 ihold(inode);
722
723 err = ovl_create_or_link(new, inode,
724 &(struct ovl_cattr) {.hardlink = ovl_dentry_upper(old)},
725 ovl_type_origin(old));
726 if (err)
727 iput(inode);
728
729 out_nlink_end:
730 ovl_nlink_end(old);
731 out:
732 return err;
733 }
734
ovl_matches_upper(struct dentry * dentry,struct dentry * upper)735 static bool ovl_matches_upper(struct dentry *dentry, struct dentry *upper)
736 {
737 return d_inode(ovl_dentry_upper(dentry)) == d_inode(upper);
738 }
739
ovl_remove_and_whiteout(struct dentry * dentry,struct list_head * list)740 static int ovl_remove_and_whiteout(struct dentry *dentry,
741 struct list_head *list)
742 {
743 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
744 struct dentry *workdir = ovl_workdir(dentry);
745 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
746 struct dentry *upper;
747 struct dentry *opaquedir = NULL;
748 int err;
749
750 if (WARN_ON(!workdir))
751 return -EROFS;
752
753 if (!list_empty(list)) {
754 opaquedir = ovl_clear_empty(dentry, list);
755 err = PTR_ERR(opaquedir);
756 if (IS_ERR(opaquedir))
757 goto out;
758 }
759
760 err = ovl_lock_rename_workdir(workdir, upperdir);
761 if (err)
762 goto out_dput;
763
764 upper = ovl_lookup_upper(ofs, dentry->d_name.name, upperdir,
765 dentry->d_name.len);
766 err = PTR_ERR(upper);
767 if (IS_ERR(upper))
768 goto out_unlock;
769
770 err = -ESTALE;
771 if ((opaquedir && upper != opaquedir) ||
772 (!opaquedir && ovl_dentry_upper(dentry) &&
773 !ovl_matches_upper(dentry, upper))) {
774 goto out_dput_upper;
775 }
776
777 err = ovl_cleanup_and_whiteout(ofs, d_inode(upperdir), upper);
778 if (err)
779 goto out_d_drop;
780
781 ovl_dir_modified(dentry->d_parent, true);
782 out_d_drop:
783 d_drop(dentry);
784 out_dput_upper:
785 dput(upper);
786 out_unlock:
787 unlock_rename(workdir, upperdir);
788 out_dput:
789 dput(opaquedir);
790 out:
791 return err;
792 }
793
ovl_remove_upper(struct dentry * dentry,bool is_dir,struct list_head * list)794 static int ovl_remove_upper(struct dentry *dentry, bool is_dir,
795 struct list_head *list)
796 {
797 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
798 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
799 struct inode *dir = upperdir->d_inode;
800 struct dentry *upper;
801 struct dentry *opaquedir = NULL;
802 int err;
803
804 if (!list_empty(list)) {
805 opaquedir = ovl_clear_empty(dentry, list);
806 err = PTR_ERR(opaquedir);
807 if (IS_ERR(opaquedir))
808 goto out;
809 }
810
811 inode_lock_nested(dir, I_MUTEX_PARENT);
812 upper = ovl_lookup_upper(ofs, dentry->d_name.name, upperdir,
813 dentry->d_name.len);
814 err = PTR_ERR(upper);
815 if (IS_ERR(upper))
816 goto out_unlock;
817
818 err = -ESTALE;
819 if ((opaquedir && upper != opaquedir) ||
820 (!opaquedir && !ovl_matches_upper(dentry, upper)))
821 goto out_dput_upper;
822
823 if (is_dir)
824 err = ovl_do_rmdir(ofs, dir, upper);
825 else
826 err = ovl_do_unlink(ofs, dir, upper);
827 ovl_dir_modified(dentry->d_parent, ovl_type_origin(dentry));
828
829 /*
830 * Keeping this dentry hashed would mean having to release
831 * upperpath/lowerpath, which could only be done if we are the
832 * sole user of this dentry. Too tricky... Just unhash for
833 * now.
834 */
835 if (!err)
836 d_drop(dentry);
837 out_dput_upper:
838 dput(upper);
839 out_unlock:
840 inode_unlock(dir);
841 dput(opaquedir);
842 out:
843 return err;
844 }
845
ovl_pure_upper(struct dentry * dentry)846 static bool ovl_pure_upper(struct dentry *dentry)
847 {
848 return !ovl_dentry_lower(dentry) &&
849 !ovl_test_flag(OVL_WHITEOUTS, d_inode(dentry));
850 }
851
ovl_drop_nlink(struct dentry * dentry)852 static void ovl_drop_nlink(struct dentry *dentry)
853 {
854 struct inode *inode = d_inode(dentry);
855 struct dentry *alias;
856
857 /* Try to find another, hashed alias */
858 spin_lock(&inode->i_lock);
859 hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
860 if (alias != dentry && !d_unhashed(alias))
861 break;
862 }
863 spin_unlock(&inode->i_lock);
864
865 /*
866 * Changes to underlying layers may cause i_nlink to lose sync with
867 * reality. In this case prevent the link count from going to zero
868 * prematurely.
869 */
870 if (inode->i_nlink > !!alias)
871 drop_nlink(inode);
872 }
873
ovl_do_remove(struct dentry * dentry,bool is_dir)874 static int ovl_do_remove(struct dentry *dentry, bool is_dir)
875 {
876 int err;
877 const struct cred *old_cred;
878 bool lower_positive = ovl_lower_positive(dentry);
879 LIST_HEAD(list);
880
881 /* No need to clean pure upper removed by vfs_rmdir() */
882 if (is_dir && (lower_positive || !ovl_pure_upper(dentry))) {
883 err = ovl_check_empty_dir(dentry, &list);
884 if (err)
885 goto out;
886 }
887
888 err = ovl_copy_up(dentry->d_parent);
889 if (err)
890 goto out;
891
892 err = ovl_nlink_start(dentry);
893 if (err)
894 goto out;
895
896 old_cred = ovl_override_creds(dentry->d_sb);
897 if (!lower_positive)
898 err = ovl_remove_upper(dentry, is_dir, &list);
899 else
900 err = ovl_remove_and_whiteout(dentry, &list);
901 ovl_revert_creds(old_cred);
902 if (!err) {
903 if (is_dir)
904 clear_nlink(dentry->d_inode);
905 else
906 ovl_drop_nlink(dentry);
907 }
908 ovl_nlink_end(dentry);
909
910 /*
911 * Copy ctime
912 *
913 * Note: we fail to update ctime if there was no copy-up, only a
914 * whiteout
915 */
916 if (ovl_dentry_upper(dentry))
917 ovl_copyattr(d_inode(dentry));
918
919 out:
920 ovl_cache_free(&list);
921 return err;
922 }
923
ovl_unlink(struct inode * dir,struct dentry * dentry)924 static int ovl_unlink(struct inode *dir, struct dentry *dentry)
925 {
926 return ovl_do_remove(dentry, false);
927 }
928
ovl_rmdir(struct inode * dir,struct dentry * dentry)929 static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
930 {
931 return ovl_do_remove(dentry, true);
932 }
933
ovl_type_merge_or_lower(struct dentry * dentry)934 static bool ovl_type_merge_or_lower(struct dentry *dentry)
935 {
936 enum ovl_path_type type = ovl_path_type(dentry);
937
938 return OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type);
939 }
940
ovl_can_move(struct dentry * dentry)941 static bool ovl_can_move(struct dentry *dentry)
942 {
943 return ovl_redirect_dir(OVL_FS(dentry->d_sb)) ||
944 !d_is_dir(dentry) || !ovl_type_merge_or_lower(dentry);
945 }
946
ovl_get_redirect(struct dentry * dentry,bool abs_redirect)947 static char *ovl_get_redirect(struct dentry *dentry, bool abs_redirect)
948 {
949 char *buf, *ret;
950 struct dentry *d, *tmp;
951 int buflen = ovl_redirect_max + 1;
952
953 if (!abs_redirect) {
954 ret = kstrndup(dentry->d_name.name, dentry->d_name.len,
955 GFP_KERNEL);
956 goto out;
957 }
958
959 buf = ret = kmalloc(buflen, GFP_KERNEL);
960 if (!buf)
961 goto out;
962
963 buflen--;
964 buf[buflen] = '\0';
965 for (d = dget(dentry); !IS_ROOT(d);) {
966 const char *name;
967 int thislen;
968
969 spin_lock(&d->d_lock);
970 name = ovl_dentry_get_redirect(d);
971 if (name) {
972 thislen = strlen(name);
973 } else {
974 name = d->d_name.name;
975 thislen = d->d_name.len;
976 }
977
978 /* If path is too long, fall back to userspace move */
979 if (thislen + (name[0] != '/') > buflen) {
980 ret = ERR_PTR(-EXDEV);
981 spin_unlock(&d->d_lock);
982 goto out_put;
983 }
984
985 buflen -= thislen;
986 memcpy(&buf[buflen], name, thislen);
987 spin_unlock(&d->d_lock);
988 tmp = dget_parent(d);
989
990 dput(d);
991 d = tmp;
992
993 /* Absolute redirect: finished */
994 if (buf[buflen] == '/')
995 break;
996 buflen--;
997 buf[buflen] = '/';
998 }
999 ret = kstrdup(&buf[buflen], GFP_KERNEL);
1000 out_put:
1001 dput(d);
1002 kfree(buf);
1003 out:
1004 return ret ? ret : ERR_PTR(-ENOMEM);
1005 }
1006
ovl_need_absolute_redirect(struct dentry * dentry,bool samedir)1007 static bool ovl_need_absolute_redirect(struct dentry *dentry, bool samedir)
1008 {
1009 struct dentry *lowerdentry;
1010
1011 if (!samedir)
1012 return true;
1013
1014 if (d_is_dir(dentry))
1015 return false;
1016
1017 /*
1018 * For non-dir hardlinked files, we need absolute redirects
1019 * in general as two upper hardlinks could be in different
1020 * dirs. We could put a relative redirect now and convert
1021 * it to absolute redirect later. But when nlink > 1 and
1022 * indexing is on, that means relative redirect needs to be
1023 * converted to absolute during copy up of another lower
1024 * hardllink as well.
1025 *
1026 * So without optimizing too much, just check if lower is
1027 * a hard link or not. If lower is hard link, put absolute
1028 * redirect.
1029 */
1030 lowerdentry = ovl_dentry_lower(dentry);
1031 return (d_inode(lowerdentry)->i_nlink > 1);
1032 }
1033
ovl_set_redirect(struct dentry * dentry,bool samedir)1034 static int ovl_set_redirect(struct dentry *dentry, bool samedir)
1035 {
1036 int err;
1037 struct ovl_fs *ofs = OVL_FS(dentry->d_sb);
1038 const char *redirect = ovl_dentry_get_redirect(dentry);
1039 bool absolute_redirect = ovl_need_absolute_redirect(dentry, samedir);
1040
1041 if (redirect && (!absolute_redirect || redirect[0] == '/'))
1042 return 0;
1043
1044 redirect = ovl_get_redirect(dentry, absolute_redirect);
1045 if (IS_ERR(redirect))
1046 return PTR_ERR(redirect);
1047
1048 err = ovl_check_setxattr(ofs, ovl_dentry_upper(dentry),
1049 OVL_XATTR_REDIRECT,
1050 redirect, strlen(redirect), -EXDEV);
1051 if (!err) {
1052 spin_lock(&dentry->d_lock);
1053 ovl_dentry_set_redirect(dentry, redirect);
1054 spin_unlock(&dentry->d_lock);
1055 } else {
1056 kfree(redirect);
1057 pr_warn_ratelimited("failed to set redirect (%i)\n",
1058 err);
1059 /* Fall back to userspace copy-up */
1060 err = -EXDEV;
1061 }
1062 return err;
1063 }
1064
ovl_rename(struct mnt_idmap * idmap,struct inode * olddir,struct dentry * old,struct inode * newdir,struct dentry * new,unsigned int flags)1065 static int ovl_rename(struct mnt_idmap *idmap, struct inode *olddir,
1066 struct dentry *old, struct inode *newdir,
1067 struct dentry *new, unsigned int flags)
1068 {
1069 int err;
1070 struct dentry *old_upperdir;
1071 struct dentry *new_upperdir;
1072 struct dentry *olddentry;
1073 struct dentry *newdentry;
1074 struct dentry *trap;
1075 bool old_opaque;
1076 bool new_opaque;
1077 bool cleanup_whiteout = false;
1078 bool update_nlink = false;
1079 bool overwrite = !(flags & RENAME_EXCHANGE);
1080 bool is_dir = d_is_dir(old);
1081 bool new_is_dir = d_is_dir(new);
1082 bool samedir = olddir == newdir;
1083 struct dentry *opaquedir = NULL;
1084 const struct cred *old_cred = NULL;
1085 struct ovl_fs *ofs = OVL_FS(old->d_sb);
1086 LIST_HEAD(list);
1087
1088 err = -EINVAL;
1089 if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
1090 goto out;
1091
1092 flags &= ~RENAME_NOREPLACE;
1093
1094 /* Don't copy up directory trees */
1095 err = -EXDEV;
1096 if (!ovl_can_move(old))
1097 goto out;
1098 if (!overwrite && !ovl_can_move(new))
1099 goto out;
1100
1101 if (overwrite && new_is_dir && !ovl_pure_upper(new)) {
1102 err = ovl_check_empty_dir(new, &list);
1103 if (err)
1104 goto out;
1105 }
1106
1107 if (overwrite) {
1108 if (ovl_lower_positive(old)) {
1109 if (!ovl_dentry_is_whiteout(new)) {
1110 /* Whiteout source */
1111 flags |= RENAME_WHITEOUT;
1112 } else {
1113 /* Switch whiteouts */
1114 flags |= RENAME_EXCHANGE;
1115 }
1116 } else if (is_dir && ovl_dentry_is_whiteout(new)) {
1117 flags |= RENAME_EXCHANGE;
1118 cleanup_whiteout = true;
1119 }
1120 }
1121
1122 err = ovl_copy_up(old);
1123 if (err)
1124 goto out;
1125
1126 err = ovl_copy_up(new->d_parent);
1127 if (err)
1128 goto out;
1129 if (!overwrite) {
1130 err = ovl_copy_up(new);
1131 if (err)
1132 goto out;
1133 } else if (d_inode(new)) {
1134 err = ovl_nlink_start(new);
1135 if (err)
1136 goto out;
1137
1138 update_nlink = true;
1139 }
1140
1141 if (!update_nlink) {
1142 /* ovl_nlink_start() took ovl_want_write() */
1143 err = ovl_want_write(old);
1144 if (err)
1145 goto out;
1146 }
1147
1148 old_cred = ovl_override_creds(old->d_sb);
1149
1150 if (!list_empty(&list)) {
1151 opaquedir = ovl_clear_empty(new, &list);
1152 err = PTR_ERR(opaquedir);
1153 if (IS_ERR(opaquedir)) {
1154 opaquedir = NULL;
1155 goto out_revert_creds;
1156 }
1157 }
1158
1159 old_upperdir = ovl_dentry_upper(old->d_parent);
1160 new_upperdir = ovl_dentry_upper(new->d_parent);
1161
1162 if (!samedir) {
1163 /*
1164 * When moving a merge dir or non-dir with copy up origin into
1165 * a new parent, we are marking the new parent dir "impure".
1166 * When ovl_iterate() iterates an "impure" upper dir, it will
1167 * lookup the origin inodes of the entries to fill d_ino.
1168 */
1169 if (ovl_type_origin(old)) {
1170 err = ovl_set_impure(new->d_parent, new_upperdir);
1171 if (err)
1172 goto out_revert_creds;
1173 }
1174 if (!overwrite && ovl_type_origin(new)) {
1175 err = ovl_set_impure(old->d_parent, old_upperdir);
1176 if (err)
1177 goto out_revert_creds;
1178 }
1179 }
1180
1181 trap = lock_rename(new_upperdir, old_upperdir);
1182 if (IS_ERR(trap)) {
1183 err = PTR_ERR(trap);
1184 goto out_revert_creds;
1185 }
1186
1187 olddentry = ovl_lookup_upper(ofs, old->d_name.name, old_upperdir,
1188 old->d_name.len);
1189 err = PTR_ERR(olddentry);
1190 if (IS_ERR(olddentry))
1191 goto out_unlock;
1192
1193 err = -ESTALE;
1194 if (!ovl_matches_upper(old, olddentry))
1195 goto out_dput_old;
1196
1197 newdentry = ovl_lookup_upper(ofs, new->d_name.name, new_upperdir,
1198 new->d_name.len);
1199 err = PTR_ERR(newdentry);
1200 if (IS_ERR(newdentry))
1201 goto out_dput_old;
1202
1203 old_opaque = ovl_dentry_is_opaque(old);
1204 new_opaque = ovl_dentry_is_opaque(new);
1205
1206 err = -ESTALE;
1207 if (d_inode(new) && ovl_dentry_upper(new)) {
1208 if (opaquedir) {
1209 if (newdentry != opaquedir)
1210 goto out_dput;
1211 } else {
1212 if (!ovl_matches_upper(new, newdentry))
1213 goto out_dput;
1214 }
1215 } else {
1216 if (!d_is_negative(newdentry)) {
1217 if (!new_opaque || !ovl_upper_is_whiteout(ofs, newdentry))
1218 goto out_dput;
1219 } else {
1220 if (flags & RENAME_EXCHANGE)
1221 goto out_dput;
1222 }
1223 }
1224
1225 if (olddentry == trap)
1226 goto out_dput;
1227 if (newdentry == trap)
1228 goto out_dput;
1229
1230 if (olddentry->d_inode == newdentry->d_inode)
1231 goto out_dput;
1232
1233 err = 0;
1234 if (ovl_type_merge_or_lower(old))
1235 err = ovl_set_redirect(old, samedir);
1236 else if (is_dir && !old_opaque && ovl_type_merge(new->d_parent))
1237 err = ovl_set_opaque_xerr(old, olddentry, -EXDEV);
1238 if (err)
1239 goto out_dput;
1240
1241 if (!overwrite && ovl_type_merge_or_lower(new))
1242 err = ovl_set_redirect(new, samedir);
1243 else if (!overwrite && new_is_dir && !new_opaque &&
1244 ovl_type_merge(old->d_parent))
1245 err = ovl_set_opaque_xerr(new, newdentry, -EXDEV);
1246 if (err)
1247 goto out_dput;
1248
1249 err = ovl_do_rename(ofs, old_upperdir->d_inode, olddentry,
1250 new_upperdir->d_inode, newdentry, flags);
1251 if (err)
1252 goto out_dput;
1253
1254 if (cleanup_whiteout)
1255 ovl_cleanup(ofs, old_upperdir->d_inode, newdentry);
1256
1257 if (overwrite && d_inode(new)) {
1258 if (new_is_dir)
1259 clear_nlink(d_inode(new));
1260 else
1261 ovl_drop_nlink(new);
1262 }
1263
1264 ovl_dir_modified(old->d_parent, ovl_type_origin(old) ||
1265 (!overwrite && ovl_type_origin(new)));
1266 ovl_dir_modified(new->d_parent, ovl_type_origin(old) ||
1267 (d_inode(new) && ovl_type_origin(new)));
1268
1269 /* copy ctime: */
1270 ovl_copyattr(d_inode(old));
1271 if (d_inode(new) && ovl_dentry_upper(new))
1272 ovl_copyattr(d_inode(new));
1273
1274 out_dput:
1275 dput(newdentry);
1276 out_dput_old:
1277 dput(olddentry);
1278 out_unlock:
1279 unlock_rename(new_upperdir, old_upperdir);
1280 out_revert_creds:
1281 ovl_revert_creds(old_cred);
1282 if (update_nlink)
1283 ovl_nlink_end(new);
1284 else
1285 ovl_drop_write(old);
1286 out:
1287 dput(opaquedir);
1288 ovl_cache_free(&list);
1289 return err;
1290 }
1291
ovl_create_tmpfile(struct file * file,struct dentry * dentry,struct inode * inode,umode_t mode)1292 static int ovl_create_tmpfile(struct file *file, struct dentry *dentry,
1293 struct inode *inode, umode_t mode)
1294 {
1295 const struct cred *old_cred, *new_cred = NULL;
1296 struct path realparentpath;
1297 struct file *realfile;
1298 struct ovl_file *of;
1299 struct dentry *newdentry;
1300 /* It's okay to set O_NOATIME, since the owner will be current fsuid */
1301 int flags = file->f_flags | OVL_OPEN_FLAGS;
1302 int err;
1303
1304 old_cred = ovl_override_creds(dentry->d_sb);
1305 new_cred = ovl_setup_cred_for_create(dentry, inode, mode, old_cred);
1306 err = PTR_ERR(new_cred);
1307 if (IS_ERR(new_cred)) {
1308 new_cred = NULL;
1309 goto out_revert_creds;
1310 }
1311
1312 ovl_path_upper(dentry->d_parent, &realparentpath);
1313 realfile = backing_tmpfile_open(&file->f_path, flags, &realparentpath,
1314 mode, current_cred());
1315 err = PTR_ERR_OR_ZERO(realfile);
1316 pr_debug("tmpfile/open(%pd2, 0%o) = %i\n", realparentpath.dentry, mode, err);
1317 if (err)
1318 goto out_revert_creds;
1319
1320 of = ovl_file_alloc(realfile);
1321 if (!of) {
1322 fput(realfile);
1323 err = -ENOMEM;
1324 goto out_revert_creds;
1325 }
1326
1327 /* ovl_instantiate() consumes the newdentry reference on success */
1328 newdentry = dget(realfile->f_path.dentry);
1329 err = ovl_instantiate(dentry, inode, newdentry, false, file);
1330 if (!err) {
1331 file->private_data = of;
1332 } else {
1333 dput(newdentry);
1334 ovl_file_free(of);
1335 }
1336 out_revert_creds:
1337 ovl_revert_creds(old_cred);
1338 put_cred(new_cred);
1339 return err;
1340 }
1341
ovl_dummy_open(struct inode * inode,struct file * file)1342 static int ovl_dummy_open(struct inode *inode, struct file *file)
1343 {
1344 return 0;
1345 }
1346
ovl_tmpfile(struct mnt_idmap * idmap,struct inode * dir,struct file * file,umode_t mode)1347 static int ovl_tmpfile(struct mnt_idmap *idmap, struct inode *dir,
1348 struct file *file, umode_t mode)
1349 {
1350 int err;
1351 struct dentry *dentry = file->f_path.dentry;
1352 struct inode *inode;
1353
1354 if (!OVL_FS(dentry->d_sb)->tmpfile)
1355 return -EOPNOTSUPP;
1356
1357 err = ovl_copy_up(dentry->d_parent);
1358 if (err)
1359 return err;
1360
1361 err = ovl_want_write(dentry);
1362 if (err)
1363 return err;
1364
1365 err = -ENOMEM;
1366 inode = ovl_new_inode(dentry->d_sb, mode, 0);
1367 if (!inode)
1368 goto drop_write;
1369
1370 inode_init_owner(&nop_mnt_idmap, inode, dir, mode);
1371 err = ovl_create_tmpfile(file, dentry, inode, inode->i_mode);
1372 if (err)
1373 goto put_inode;
1374
1375 /*
1376 * Check if the preallocated inode was actually used. Having something
1377 * else assigned to the dentry shouldn't happen as that would indicate
1378 * that the backing tmpfile "leaked" out of overlayfs.
1379 */
1380 err = -EIO;
1381 if (WARN_ON(inode != d_inode(dentry)))
1382 goto put_realfile;
1383
1384 /* inode reference was transferred to dentry */
1385 inode = NULL;
1386 err = finish_open(file, dentry, ovl_dummy_open);
1387 put_realfile:
1388 /* Without FMODE_OPENED ->release() won't be called on @file */
1389 if (!(file->f_mode & FMODE_OPENED))
1390 ovl_file_free(file->private_data);
1391 put_inode:
1392 iput(inode);
1393 drop_write:
1394 ovl_drop_write(dentry);
1395 return err;
1396 }
1397
1398 const struct inode_operations ovl_dir_inode_operations = {
1399 .lookup = ovl_lookup,
1400 .mkdir = ovl_mkdir,
1401 .symlink = ovl_symlink,
1402 .unlink = ovl_unlink,
1403 .rmdir = ovl_rmdir,
1404 .rename = ovl_rename,
1405 .link = ovl_link,
1406 .setattr = ovl_setattr,
1407 .create = ovl_create,
1408 .mknod = ovl_mknod,
1409 .permission = ovl_permission,
1410 .getattr = ovl_getattr,
1411 .listxattr = ovl_listxattr,
1412 .get_inode_acl = ovl_get_inode_acl,
1413 .get_acl = ovl_get_acl,
1414 .set_acl = ovl_set_acl,
1415 .update_time = ovl_update_time,
1416 .fileattr_get = ovl_fileattr_get,
1417 .fileattr_set = ovl_fileattr_set,
1418 .tmpfile = ovl_tmpfile,
1419 };
1420