Commit | Line | Data |
---|---|---|
e9be9d5e MS |
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 | ||
17 | void ovl_cleanup(struct inode *wdir, struct dentry *wdentry) | |
18 | { | |
19 | int err; | |
20 | ||
21 | dget(wdentry); | |
e36cb0b8 | 22 | if (d_is_dir(wdentry)) |
e9be9d5e 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 | ||
34 | struct 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 */ | |
52 | static 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 | ||
72 | int 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 | ||
119 | static int ovl_set_opaque(struct dentry *upperdentry) | |
120 | { | |
cead89bb | 121 | return ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0); |
e9be9d5e MS |
122 | } |
123 | ||
124 | static void ovl_remove_opaque(struct dentry *upperdentry) | |
125 | { | |
126 | int err; | |
127 | ||
cead89bb | 128 | err = ovl_do_removexattr(upperdentry, OVL_XATTR_OPAQUE); |
e9be9d5e MS |
129 | if (err) { |
130 | pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n", | |
131 | upperdentry->d_name.name, err); | |
132 | } | |
133 | } | |
134 | ||
135 | static 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; | |
1175b6b8 | 141 | const struct cred *old_cred; |
e9be9d5e MS |
142 | |
143 | type = ovl_path_real(dentry, &realpath); | |
1175b6b8 | 144 | old_cred = ovl_override_creds(dentry->d_sb); |
e9be9d5e | 145 | err = vfs_getattr(&realpath, stat); |
1175b6b8 | 146 | revert_creds(old_cred); |
e9be9d5e MS |
147 | if (err) |
148 | return err; | |
149 | ||
150 | stat->dev = dentry->d_sb->s_dev; | |
151 | stat->ino = dentry->d_inode->i_ino; | |
152 | ||
153 | /* | |
154 | * It's probably not worth it to count subdirs to get the | |
155 | * correct link count. nlink=1 seems to pacify 'find' and | |
156 | * other utilities. | |
157 | */ | |
1afaba1e | 158 | if (OVL_TYPE_MERGE(type)) |
e9be9d5e MS |
159 | stat->nlink = 1; |
160 | ||
161 | return 0; | |
162 | } | |
163 | ||
72e48481 VG |
164 | /* Common operations required to be done after creation of file on upper */ |
165 | static void ovl_instantiate(struct dentry *dentry, struct inode *inode, | |
166 | struct dentry *newdentry) | |
167 | { | |
168 | ovl_dentry_version_inc(dentry->d_parent); | |
169 | ovl_dentry_update(dentry, newdentry); | |
39b681f8 | 170 | ovl_inode_update(inode, d_inode(newdentry)); |
72e48481 VG |
171 | ovl_copyattr(newdentry->d_inode, inode); |
172 | d_instantiate(dentry, inode); | |
173 | } | |
174 | ||
e9be9d5e MS |
175 | static int ovl_create_upper(struct dentry *dentry, struct inode *inode, |
176 | struct kstat *stat, const char *link, | |
177 | struct dentry *hardlink) | |
178 | { | |
179 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
180 | struct inode *udir = upperdir->d_inode; | |
181 | struct dentry *newdentry; | |
182 | int err; | |
183 | ||
5955102c | 184 | inode_lock_nested(udir, I_MUTEX_PARENT); |
e9be9d5e MS |
185 | newdentry = lookup_one_len(dentry->d_name.name, upperdir, |
186 | dentry->d_name.len); | |
187 | err = PTR_ERR(newdentry); | |
188 | if (IS_ERR(newdentry)) | |
189 | goto out_unlock; | |
190 | err = ovl_create_real(udir, newdentry, stat, link, hardlink, false); | |
191 | if (err) | |
192 | goto out_dput; | |
193 | ||
72e48481 | 194 | ovl_instantiate(dentry, inode, newdentry); |
e9be9d5e MS |
195 | newdentry = NULL; |
196 | out_dput: | |
197 | dput(newdentry); | |
198 | out_unlock: | |
5955102c | 199 | inode_unlock(udir); |
e9be9d5e MS |
200 | return err; |
201 | } | |
202 | ||
203 | static int ovl_lock_rename_workdir(struct dentry *workdir, | |
204 | struct dentry *upperdir) | |
205 | { | |
206 | /* Workdir should not be the same as upperdir */ | |
207 | if (workdir == upperdir) | |
208 | goto err; | |
209 | ||
210 | /* Workdir should not be subdir of upperdir and vice versa */ | |
211 | if (lock_rename(workdir, upperdir) != NULL) | |
212 | goto err_unlock; | |
213 | ||
214 | return 0; | |
215 | ||
216 | err_unlock: | |
217 | unlock_rename(workdir, upperdir); | |
218 | err: | |
219 | pr_err("overlayfs: failed to lock workdir+upperdir\n"); | |
220 | return -EIO; | |
221 | } | |
222 | ||
223 | static struct dentry *ovl_clear_empty(struct dentry *dentry, | |
224 | struct list_head *list) | |
225 | { | |
226 | struct dentry *workdir = ovl_workdir(dentry); | |
227 | struct inode *wdir = workdir->d_inode; | |
228 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
229 | struct inode *udir = upperdir->d_inode; | |
230 | struct path upperpath; | |
231 | struct dentry *upper; | |
232 | struct dentry *opaquedir; | |
233 | struct kstat stat; | |
234 | int err; | |
235 | ||
cc6f67bc MS |
236 | if (WARN_ON(!workdir)) |
237 | return ERR_PTR(-EROFS); | |
238 | ||
e9be9d5e MS |
239 | err = ovl_lock_rename_workdir(workdir, upperdir); |
240 | if (err) | |
241 | goto out; | |
242 | ||
243 | ovl_path_upper(dentry, &upperpath); | |
244 | err = vfs_getattr(&upperpath, &stat); | |
245 | if (err) | |
246 | goto out_unlock; | |
247 | ||
248 | err = -ESTALE; | |
249 | if (!S_ISDIR(stat.mode)) | |
250 | goto out_unlock; | |
251 | upper = upperpath.dentry; | |
252 | if (upper->d_parent->d_inode != udir) | |
253 | goto out_unlock; | |
254 | ||
255 | opaquedir = ovl_lookup_temp(workdir, dentry); | |
256 | err = PTR_ERR(opaquedir); | |
257 | if (IS_ERR(opaquedir)) | |
258 | goto out_unlock; | |
259 | ||
260 | err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true); | |
261 | if (err) | |
262 | goto out_dput; | |
263 | ||
264 | err = ovl_copy_xattr(upper, opaquedir); | |
265 | if (err) | |
266 | goto out_cleanup; | |
267 | ||
268 | err = ovl_set_opaque(opaquedir); | |
269 | if (err) | |
270 | goto out_cleanup; | |
271 | ||
5955102c | 272 | inode_lock(opaquedir->d_inode); |
e9be9d5e | 273 | err = ovl_set_attr(opaquedir, &stat); |
5955102c | 274 | inode_unlock(opaquedir->d_inode); |
e9be9d5e MS |
275 | if (err) |
276 | goto out_cleanup; | |
277 | ||
278 | err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE); | |
279 | if (err) | |
280 | goto out_cleanup; | |
281 | ||
282 | ovl_cleanup_whiteouts(upper, list); | |
283 | ovl_cleanup(wdir, upper); | |
284 | unlock_rename(workdir, upperdir); | |
285 | ||
286 | /* dentry's upper doesn't match now, get rid of it */ | |
287 | d_drop(dentry); | |
288 | ||
289 | return opaquedir; | |
290 | ||
291 | out_cleanup: | |
292 | ovl_cleanup(wdir, opaquedir); | |
293 | out_dput: | |
294 | dput(opaquedir); | |
295 | out_unlock: | |
296 | unlock_rename(workdir, upperdir); | |
297 | out: | |
298 | return ERR_PTR(err); | |
299 | } | |
300 | ||
a105d685 | 301 | static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry) |
e9be9d5e MS |
302 | { |
303 | int err; | |
304 | struct dentry *ret = NULL; | |
305 | LIST_HEAD(list); | |
306 | ||
307 | err = ovl_check_empty_dir(dentry, &list); | |
308 | if (err) | |
309 | ret = ERR_PTR(err); | |
a105d685 MS |
310 | else { |
311 | /* | |
312 | * If no upperdentry then skip clearing whiteouts. | |
313 | * | |
314 | * Can race with copy-up, since we don't hold the upperdir | |
315 | * mutex. Doesn't matter, since copy-up can't create a | |
316 | * non-empty directory from an empty one. | |
317 | */ | |
318 | if (ovl_dentry_upper(dentry)) | |
319 | ret = ovl_clear_empty(dentry, &list); | |
320 | } | |
e9be9d5e MS |
321 | |
322 | ovl_cache_free(&list); | |
323 | ||
324 | return ret; | |
325 | } | |
326 | ||
327 | static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, | |
328 | struct kstat *stat, const char *link, | |
329 | struct dentry *hardlink) | |
330 | { | |
331 | struct dentry *workdir = ovl_workdir(dentry); | |
332 | struct inode *wdir = workdir->d_inode; | |
333 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
334 | struct inode *udir = upperdir->d_inode; | |
335 | struct dentry *upper; | |
336 | struct dentry *newdentry; | |
337 | int err; | |
338 | ||
cc6f67bc MS |
339 | if (WARN_ON(!workdir)) |
340 | return -EROFS; | |
341 | ||
e9be9d5e MS |
342 | err = ovl_lock_rename_workdir(workdir, upperdir); |
343 | if (err) | |
344 | goto out; | |
345 | ||
346 | newdentry = ovl_lookup_temp(workdir, dentry); | |
347 | err = PTR_ERR(newdentry); | |
348 | if (IS_ERR(newdentry)) | |
349 | goto out_unlock; | |
350 | ||
351 | upper = lookup_one_len(dentry->d_name.name, upperdir, | |
352 | dentry->d_name.len); | |
353 | err = PTR_ERR(upper); | |
354 | if (IS_ERR(upper)) | |
355 | goto out_dput; | |
356 | ||
357 | err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true); | |
358 | if (err) | |
359 | goto out_dput2; | |
360 | ||
bb0d2b8a MS |
361 | /* |
362 | * mode could have been mutilated due to umask (e.g. sgid directory) | |
363 | */ | |
364 | if (!S_ISLNK(stat->mode) && newdentry->d_inode->i_mode != stat->mode) { | |
365 | struct iattr attr = { | |
366 | .ia_valid = ATTR_MODE, | |
367 | .ia_mode = stat->mode, | |
368 | }; | |
369 | inode_lock(newdentry->d_inode); | |
370 | err = notify_change(newdentry, &attr, NULL); | |
371 | inode_unlock(newdentry->d_inode); | |
372 | if (err) | |
373 | goto out_cleanup; | |
374 | } | |
375 | ||
e9be9d5e MS |
376 | if (S_ISDIR(stat->mode)) { |
377 | err = ovl_set_opaque(newdentry); | |
378 | if (err) | |
379 | goto out_cleanup; | |
380 | ||
381 | err = ovl_do_rename(wdir, newdentry, udir, upper, | |
382 | RENAME_EXCHANGE); | |
383 | if (err) | |
384 | goto out_cleanup; | |
385 | ||
386 | ovl_cleanup(wdir, upper); | |
387 | } else { | |
388 | err = ovl_do_rename(wdir, newdentry, udir, upper, 0); | |
389 | if (err) | |
390 | goto out_cleanup; | |
391 | } | |
72e48481 | 392 | ovl_instantiate(dentry, inode, newdentry); |
e9be9d5e MS |
393 | newdentry = NULL; |
394 | out_dput2: | |
395 | dput(upper); | |
396 | out_dput: | |
397 | dput(newdentry); | |
398 | out_unlock: | |
399 | unlock_rename(workdir, upperdir); | |
400 | out: | |
401 | return err; | |
402 | ||
403 | out_cleanup: | |
404 | ovl_cleanup(wdir, newdentry); | |
405 | goto out_dput2; | |
406 | } | |
407 | ||
408 | static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev, | |
409 | const char *link, struct dentry *hardlink) | |
410 | { | |
411 | int err; | |
412 | struct inode *inode; | |
1175b6b8 VG |
413 | const struct cred *old_cred; |
414 | struct cred *override_cred; | |
e9be9d5e | 415 | struct kstat stat = { |
e9be9d5e MS |
416 | .rdev = rdev, |
417 | }; | |
418 | ||
419 | err = -ENOMEM; | |
39b681f8 | 420 | inode = ovl_new_inode(dentry->d_sb, mode); |
e9be9d5e MS |
421 | if (!inode) |
422 | goto out; | |
423 | ||
424 | err = ovl_copy_up(dentry->d_parent); | |
425 | if (err) | |
426 | goto out_iput; | |
427 | ||
bb0d2b8a MS |
428 | inode_init_owner(inode, dentry->d_parent->d_inode, mode); |
429 | stat.mode = inode->i_mode; | |
430 | ||
1175b6b8 VG |
431 | old_cred = ovl_override_creds(dentry->d_sb); |
432 | err = -ENOMEM; | |
433 | override_cred = prepare_creds(); | |
434 | if (override_cred) { | |
bb0d2b8a MS |
435 | override_cred->fsuid = inode->i_uid; |
436 | override_cred->fsgid = inode->i_gid; | |
1175b6b8 VG |
437 | put_cred(override_creds(override_cred)); |
438 | put_cred(override_cred); | |
439 | ||
440 | if (!ovl_dentry_is_opaque(dentry)) | |
441 | err = ovl_create_upper(dentry, inode, &stat, link, | |
442 | hardlink); | |
443 | else | |
d0e13f5b | 444 | err = ovl_create_over_whiteout(dentry, inode, &stat, |
1175b6b8 | 445 | link, hardlink); |
e9be9d5e | 446 | } |
1175b6b8 | 447 | revert_creds(old_cred); |
bb0d2b8a MS |
448 | if (!err) { |
449 | struct inode *realinode = d_inode(ovl_dentry_upper(dentry)); | |
450 | ||
451 | WARN_ON(inode->i_mode != realinode->i_mode); | |
452 | WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid)); | |
453 | WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid)); | |
e9be9d5e | 454 | inode = NULL; |
bb0d2b8a | 455 | } |
e9be9d5e MS |
456 | out_iput: |
457 | iput(inode); | |
458 | out: | |
459 | return err; | |
460 | } | |
461 | ||
462 | static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, | |
463 | const char *link) | |
464 | { | |
465 | int err; | |
466 | ||
467 | err = ovl_want_write(dentry); | |
468 | if (!err) { | |
469 | err = ovl_create_or_link(dentry, mode, rdev, link, NULL); | |
470 | ovl_drop_write(dentry); | |
471 | } | |
472 | ||
473 | return err; | |
474 | } | |
475 | ||
476 | static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode, | |
477 | bool excl) | |
478 | { | |
479 | return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL); | |
480 | } | |
481 | ||
482 | static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) | |
483 | { | |
484 | return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL); | |
485 | } | |
486 | ||
487 | static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, | |
488 | dev_t rdev) | |
489 | { | |
490 | /* Don't allow creation of "whiteout" on overlay */ | |
491 | if (S_ISCHR(mode) && rdev == WHITEOUT_DEV) | |
492 | return -EPERM; | |
493 | ||
494 | return ovl_create_object(dentry, mode, rdev, NULL); | |
495 | } | |
496 | ||
497 | static int ovl_symlink(struct inode *dir, struct dentry *dentry, | |
498 | const char *link) | |
499 | { | |
500 | return ovl_create_object(dentry, S_IFLNK, 0, link); | |
501 | } | |
502 | ||
503 | static int ovl_link(struct dentry *old, struct inode *newdir, | |
504 | struct dentry *new) | |
505 | { | |
506 | int err; | |
507 | struct dentry *upper; | |
508 | ||
509 | err = ovl_want_write(old); | |
510 | if (err) | |
511 | goto out; | |
512 | ||
513 | err = ovl_copy_up(old); | |
514 | if (err) | |
515 | goto out_drop_write; | |
516 | ||
517 | upper = ovl_dentry_upper(old); | |
518 | err = ovl_create_or_link(new, upper->d_inode->i_mode, 0, NULL, upper); | |
519 | ||
520 | out_drop_write: | |
521 | ovl_drop_write(old); | |
522 | out: | |
523 | return err; | |
524 | } | |
525 | ||
a105d685 | 526 | static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir) |
e9be9d5e MS |
527 | { |
528 | struct dentry *workdir = ovl_workdir(dentry); | |
529 | struct inode *wdir = workdir->d_inode; | |
530 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
531 | struct inode *udir = upperdir->d_inode; | |
532 | struct dentry *whiteout; | |
533 | struct dentry *upper; | |
534 | struct dentry *opaquedir = NULL; | |
535 | int err; | |
cfc9fde0 | 536 | int flags = 0; |
e9be9d5e | 537 | |
cc6f67bc MS |
538 | if (WARN_ON(!workdir)) |
539 | return -EROFS; | |
540 | ||
d377c5eb MS |
541 | if (is_dir) { |
542 | if (OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) { | |
543 | opaquedir = ovl_check_empty_and_clear(dentry); | |
544 | err = PTR_ERR(opaquedir); | |
545 | if (IS_ERR(opaquedir)) | |
546 | goto out; | |
547 | } else { | |
548 | LIST_HEAD(list); | |
549 | ||
550 | /* | |
551 | * When removing an empty opaque directory, then it | |
552 | * makes no sense to replace it with an exact replica of | |
553 | * itself. But emptiness still needs to be checked. | |
554 | */ | |
555 | err = ovl_check_empty_dir(dentry, &list); | |
556 | ovl_cache_free(&list); | |
557 | if (err) | |
558 | goto out; | |
559 | } | |
e9be9d5e MS |
560 | } |
561 | ||
562 | err = ovl_lock_rename_workdir(workdir, upperdir); | |
563 | if (err) | |
564 | goto out_dput; | |
565 | ||
cfc9fde0 MP |
566 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
567 | dentry->d_name.len); | |
568 | err = PTR_ERR(upper); | |
569 | if (IS_ERR(upper)) | |
e9be9d5e MS |
570 | goto out_unlock; |
571 | ||
cfc9fde0 MP |
572 | err = -ESTALE; |
573 | if ((opaquedir && upper != opaquedir) || | |
574 | (!opaquedir && ovl_dentry_upper(dentry) && | |
575 | upper != ovl_dentry_upper(dentry))) { | |
576 | goto out_dput_upper; | |
577 | } | |
e9be9d5e | 578 | |
cfc9fde0 MP |
579 | whiteout = ovl_whiteout(workdir, dentry); |
580 | err = PTR_ERR(whiteout); | |
581 | if (IS_ERR(whiteout)) | |
582 | goto out_dput_upper; | |
e9be9d5e | 583 | |
cfc9fde0 MP |
584 | if (d_is_dir(upper)) |
585 | flags = RENAME_EXCHANGE; | |
e9be9d5e | 586 | |
cfc9fde0 MP |
587 | err = ovl_do_rename(wdir, whiteout, udir, upper, flags); |
588 | if (err) | |
589 | goto kill_whiteout; | |
590 | if (flags) | |
591 | ovl_cleanup(wdir, upper); | |
e9be9d5e | 592 | |
e9be9d5e MS |
593 | ovl_dentry_version_inc(dentry->d_parent); |
594 | out_d_drop: | |
595 | d_drop(dentry); | |
596 | dput(whiteout); | |
cfc9fde0 MP |
597 | out_dput_upper: |
598 | dput(upper); | |
e9be9d5e MS |
599 | out_unlock: |
600 | unlock_rename(workdir, upperdir); | |
601 | out_dput: | |
602 | dput(opaquedir); | |
603 | out: | |
604 | return err; | |
605 | ||
606 | kill_whiteout: | |
607 | ovl_cleanup(wdir, whiteout); | |
608 | goto out_d_drop; | |
609 | } | |
610 | ||
611 | static int ovl_remove_upper(struct dentry *dentry, bool is_dir) | |
612 | { | |
613 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
614 | struct inode *dir = upperdir->d_inode; | |
11f37104 | 615 | struct dentry *upper; |
e9be9d5e MS |
616 | int err; |
617 | ||
5955102c | 618 | inode_lock_nested(dir, I_MUTEX_PARENT); |
11f37104 MS |
619 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
620 | dentry->d_name.len); | |
621 | err = PTR_ERR(upper); | |
622 | if (IS_ERR(upper)) | |
623 | goto out_unlock; | |
624 | ||
e9be9d5e | 625 | err = -ESTALE; |
11f37104 | 626 | if (upper == ovl_dentry_upper(dentry)) { |
e9be9d5e MS |
627 | if (is_dir) |
628 | err = vfs_rmdir(dir, upper); | |
629 | else | |
630 | err = vfs_unlink(dir, upper, NULL); | |
e9be9d5e MS |
631 | ovl_dentry_version_inc(dentry->d_parent); |
632 | } | |
11f37104 | 633 | dput(upper); |
e9be9d5e MS |
634 | |
635 | /* | |
636 | * Keeping this dentry hashed would mean having to release | |
637 | * upperpath/lowerpath, which could only be done if we are the | |
638 | * sole user of this dentry. Too tricky... Just unhash for | |
639 | * now. | |
640 | */ | |
ce9113bb RW |
641 | if (!err) |
642 | d_drop(dentry); | |
11f37104 | 643 | out_unlock: |
5955102c | 644 | inode_unlock(dir); |
e9be9d5e MS |
645 | |
646 | return err; | |
647 | } | |
648 | ||
649 | static inline int ovl_check_sticky(struct dentry *dentry) | |
650 | { | |
651 | struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode; | |
652 | struct inode *inode = ovl_dentry_real(dentry)->d_inode; | |
653 | ||
654 | if (check_sticky(dir, inode)) | |
655 | return -EPERM; | |
656 | ||
657 | return 0; | |
658 | } | |
659 | ||
660 | static int ovl_do_remove(struct dentry *dentry, bool is_dir) | |
661 | { | |
662 | enum ovl_path_type type; | |
663 | int err; | |
1175b6b8 VG |
664 | const struct cred *old_cred; |
665 | ||
e9be9d5e MS |
666 | |
667 | err = ovl_check_sticky(dentry); | |
668 | if (err) | |
669 | goto out; | |
670 | ||
671 | err = ovl_want_write(dentry); | |
672 | if (err) | |
673 | goto out; | |
674 | ||
675 | err = ovl_copy_up(dentry->d_parent); | |
676 | if (err) | |
677 | goto out_drop_write; | |
678 | ||
679 | type = ovl_path_type(dentry); | |
e9be9d5e | 680 | |
1175b6b8 VG |
681 | old_cred = ovl_override_creds(dentry->d_sb); |
682 | if (OVL_TYPE_PURE_UPPER(type)) | |
683 | err = ovl_remove_upper(dentry, is_dir); | |
684 | else | |
a105d685 | 685 | err = ovl_remove_and_whiteout(dentry, is_dir); |
1175b6b8 | 686 | revert_creds(old_cred); |
e9be9d5e MS |
687 | out_drop_write: |
688 | ovl_drop_write(dentry); | |
689 | out: | |
690 | return err; | |
691 | } | |
692 | ||
693 | static int ovl_unlink(struct inode *dir, struct dentry *dentry) | |
694 | { | |
695 | return ovl_do_remove(dentry, false); | |
696 | } | |
697 | ||
698 | static int ovl_rmdir(struct inode *dir, struct dentry *dentry) | |
699 | { | |
700 | return ovl_do_remove(dentry, true); | |
701 | } | |
702 | ||
703 | static int ovl_rename2(struct inode *olddir, struct dentry *old, | |
704 | struct inode *newdir, struct dentry *new, | |
705 | unsigned int flags) | |
706 | { | |
707 | int err; | |
708 | enum ovl_path_type old_type; | |
709 | enum ovl_path_type new_type; | |
710 | struct dentry *old_upperdir; | |
711 | struct dentry *new_upperdir; | |
712 | struct dentry *olddentry; | |
713 | struct dentry *newdentry; | |
714 | struct dentry *trap; | |
715 | bool old_opaque; | |
716 | bool new_opaque; | |
e9be9d5e MS |
717 | bool cleanup_whiteout = false; |
718 | bool overwrite = !(flags & RENAME_EXCHANGE); | |
e36cb0b8 | 719 | bool is_dir = d_is_dir(old); |
e9be9d5e MS |
720 | bool new_is_dir = false; |
721 | struct dentry *opaquedir = NULL; | |
722 | const struct cred *old_cred = NULL; | |
e9be9d5e MS |
723 | |
724 | err = -EINVAL; | |
725 | if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) | |
726 | goto out; | |
727 | ||
728 | flags &= ~RENAME_NOREPLACE; | |
729 | ||
730 | err = ovl_check_sticky(old); | |
731 | if (err) | |
732 | goto out; | |
733 | ||
734 | /* Don't copy up directory trees */ | |
735 | old_type = ovl_path_type(old); | |
736 | err = -EXDEV; | |
1afaba1e | 737 | if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir) |
e9be9d5e MS |
738 | goto out; |
739 | ||
740 | if (new->d_inode) { | |
741 | err = ovl_check_sticky(new); | |
742 | if (err) | |
743 | goto out; | |
744 | ||
e36cb0b8 | 745 | if (d_is_dir(new)) |
e9be9d5e MS |
746 | new_is_dir = true; |
747 | ||
748 | new_type = ovl_path_type(new); | |
749 | err = -EXDEV; | |
1afaba1e | 750 | if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) |
e9be9d5e MS |
751 | goto out; |
752 | ||
753 | err = 0; | |
1afaba1e | 754 | if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) { |
e9be9d5e MS |
755 | if (ovl_dentry_lower(old)->d_inode == |
756 | ovl_dentry_lower(new)->d_inode) | |
757 | goto out; | |
758 | } | |
1afaba1e | 759 | if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) { |
e9be9d5e MS |
760 | if (ovl_dentry_upper(old)->d_inode == |
761 | ovl_dentry_upper(new)->d_inode) | |
762 | goto out; | |
763 | } | |
764 | } else { | |
765 | if (ovl_dentry_is_opaque(new)) | |
1afaba1e | 766 | new_type = __OVL_PATH_UPPER; |
e9be9d5e | 767 | else |
1afaba1e | 768 | new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE; |
e9be9d5e MS |
769 | } |
770 | ||
771 | err = ovl_want_write(old); | |
772 | if (err) | |
773 | goto out; | |
774 | ||
775 | err = ovl_copy_up(old); | |
776 | if (err) | |
777 | goto out_drop_write; | |
778 | ||
779 | err = ovl_copy_up(new->d_parent); | |
780 | if (err) | |
781 | goto out_drop_write; | |
782 | if (!overwrite) { | |
783 | err = ovl_copy_up(new); | |
784 | if (err) | |
785 | goto out_drop_write; | |
786 | } | |
787 | ||
1afaba1e MS |
788 | old_opaque = !OVL_TYPE_PURE_UPPER(old_type); |
789 | new_opaque = !OVL_TYPE_PURE_UPPER(new_type); | |
e9be9d5e | 790 | |
1175b6b8 | 791 | old_cred = ovl_override_creds(old->d_sb); |
e9be9d5e | 792 | |
1afaba1e | 793 | if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) { |
a105d685 | 794 | opaquedir = ovl_check_empty_and_clear(new); |
e9be9d5e MS |
795 | err = PTR_ERR(opaquedir); |
796 | if (IS_ERR(opaquedir)) { | |
797 | opaquedir = NULL; | |
798 | goto out_revert_creds; | |
799 | } | |
800 | } | |
801 | ||
802 | if (overwrite) { | |
803 | if (old_opaque) { | |
804 | if (new->d_inode || !new_opaque) { | |
805 | /* Whiteout source */ | |
806 | flags |= RENAME_WHITEOUT; | |
807 | } else { | |
808 | /* Switch whiteouts */ | |
809 | flags |= RENAME_EXCHANGE; | |
810 | } | |
811 | } else if (is_dir && !new->d_inode && new_opaque) { | |
812 | flags |= RENAME_EXCHANGE; | |
813 | cleanup_whiteout = true; | |
814 | } | |
815 | } | |
816 | ||
817 | old_upperdir = ovl_dentry_upper(old->d_parent); | |
818 | new_upperdir = ovl_dentry_upper(new->d_parent); | |
819 | ||
820 | trap = lock_rename(new_upperdir, old_upperdir); | |
821 | ||
11f37104 MS |
822 | |
823 | olddentry = lookup_one_len(old->d_name.name, old_upperdir, | |
824 | old->d_name.len); | |
825 | err = PTR_ERR(olddentry); | |
826 | if (IS_ERR(olddentry)) | |
827 | goto out_unlock; | |
828 | ||
829 | err = -ESTALE; | |
830 | if (olddentry != ovl_dentry_upper(old)) | |
831 | goto out_dput_old; | |
832 | ||
833 | newdentry = lookup_one_len(new->d_name.name, new_upperdir, | |
834 | new->d_name.len); | |
835 | err = PTR_ERR(newdentry); | |
836 | if (IS_ERR(newdentry)) | |
837 | goto out_dput_old; | |
838 | ||
839 | err = -ESTALE; | |
840 | if (ovl_dentry_upper(new)) { | |
e9be9d5e | 841 | if (opaquedir) { |
11f37104 MS |
842 | if (newdentry != opaquedir) |
843 | goto out_dput; | |
e9be9d5e | 844 | } else { |
11f37104 MS |
845 | if (newdentry != ovl_dentry_upper(new)) |
846 | goto out_dput; | |
e9be9d5e MS |
847 | } |
848 | } else { | |
11f37104 MS |
849 | if (!d_is_negative(newdentry) && |
850 | (!new_opaque || !ovl_is_whiteout(newdentry))) | |
851 | goto out_dput; | |
e9be9d5e MS |
852 | } |
853 | ||
e9be9d5e MS |
854 | if (olddentry == trap) |
855 | goto out_dput; | |
856 | if (newdentry == trap) | |
857 | goto out_dput; | |
858 | ||
859 | if (is_dir && !old_opaque && new_opaque) { | |
860 | err = ovl_set_opaque(olddentry); | |
861 | if (err) | |
862 | goto out_dput; | |
863 | } | |
864 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) { | |
865 | err = ovl_set_opaque(newdentry); | |
866 | if (err) | |
867 | goto out_dput; | |
868 | } | |
869 | ||
870 | if (old_opaque || new_opaque) { | |
871 | err = ovl_do_rename(old_upperdir->d_inode, olddentry, | |
872 | new_upperdir->d_inode, newdentry, | |
873 | flags); | |
874 | } else { | |
875 | /* No debug for the plain case */ | |
876 | BUG_ON(flags & ~RENAME_EXCHANGE); | |
877 | err = vfs_rename(old_upperdir->d_inode, olddentry, | |
878 | new_upperdir->d_inode, newdentry, | |
879 | NULL, flags); | |
880 | } | |
881 | ||
882 | if (err) { | |
883 | if (is_dir && !old_opaque && new_opaque) | |
884 | ovl_remove_opaque(olddentry); | |
885 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) | |
886 | ovl_remove_opaque(newdentry); | |
887 | goto out_dput; | |
888 | } | |
889 | ||
890 | if (is_dir && old_opaque && !new_opaque) | |
891 | ovl_remove_opaque(olddentry); | |
892 | if (!overwrite && new_is_dir && !old_opaque && new_opaque) | |
893 | ovl_remove_opaque(newdentry); | |
894 | ||
45d11738 KK |
895 | /* |
896 | * Old dentry now lives in different location. Dentries in | |
897 | * lowerstack are stale. We cannot drop them here because | |
898 | * access to them is lockless. This could be only pure upper | |
899 | * or opaque directory - numlower is zero. Or upper non-dir | |
900 | * entry - its pureness is tracked by flag opaque. | |
901 | */ | |
e9be9d5e MS |
902 | if (old_opaque != new_opaque) { |
903 | ovl_dentry_set_opaque(old, new_opaque); | |
904 | if (!overwrite) | |
905 | ovl_dentry_set_opaque(new, old_opaque); | |
906 | } | |
907 | ||
908 | if (cleanup_whiteout) | |
909 | ovl_cleanup(old_upperdir->d_inode, newdentry); | |
910 | ||
911 | ovl_dentry_version_inc(old->d_parent); | |
912 | ovl_dentry_version_inc(new->d_parent); | |
913 | ||
914 | out_dput: | |
915 | dput(newdentry); | |
11f37104 MS |
916 | out_dput_old: |
917 | dput(olddentry); | |
e9be9d5e MS |
918 | out_unlock: |
919 | unlock_rename(new_upperdir, old_upperdir); | |
920 | out_revert_creds: | |
1175b6b8 | 921 | revert_creds(old_cred); |
e9be9d5e MS |
922 | out_drop_write: |
923 | ovl_drop_write(old); | |
924 | out: | |
925 | dput(opaquedir); | |
926 | return err; | |
927 | } | |
928 | ||
929 | const struct inode_operations ovl_dir_inode_operations = { | |
930 | .lookup = ovl_lookup, | |
931 | .mkdir = ovl_mkdir, | |
932 | .symlink = ovl_symlink, | |
933 | .unlink = ovl_unlink, | |
934 | .rmdir = ovl_rmdir, | |
935 | .rename2 = ovl_rename2, | |
936 | .link = ovl_link, | |
937 | .setattr = ovl_setattr, | |
938 | .create = ovl_create, | |
939 | .mknod = ovl_mknod, | |
940 | .permission = ovl_permission, | |
941 | .getattr = ovl_dir_getattr, | |
942 | .setxattr = ovl_setxattr, | |
943 | .getxattr = ovl_getxattr, | |
944 | .listxattr = ovl_listxattr, | |
945 | .removexattr = ovl_removexattr, | |
39a25b2b | 946 | .get_acl = ovl_get_acl, |
d719e8f2 | 947 | .update_time = ovl_update_time, |
e9be9d5e | 948 | }; |