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, | |
51f7e52d | 166 | struct dentry *newdentry, bool hardlink) |
72e48481 VG |
167 | { |
168 | ovl_dentry_version_inc(dentry->d_parent); | |
169 | ovl_dentry_update(dentry, newdentry); | |
51f7e52d MS |
170 | if (!hardlink) { |
171 | ovl_inode_update(inode, d_inode(newdentry)); | |
172 | ovl_copyattr(newdentry->d_inode, inode); | |
173 | } else { | |
174 | WARN_ON(ovl_inode_real(inode, NULL) != d_inode(newdentry)); | |
175 | inc_nlink(inode); | |
176 | } | |
72e48481 VG |
177 | d_instantiate(dentry, inode); |
178 | } | |
179 | ||
e9be9d5e MS |
180 | static int ovl_create_upper(struct dentry *dentry, struct inode *inode, |
181 | struct kstat *stat, const char *link, | |
182 | struct dentry *hardlink) | |
183 | { | |
184 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
185 | struct inode *udir = upperdir->d_inode; | |
186 | struct dentry *newdentry; | |
187 | int err; | |
188 | ||
5955102c | 189 | inode_lock_nested(udir, I_MUTEX_PARENT); |
e9be9d5e MS |
190 | newdentry = lookup_one_len(dentry->d_name.name, upperdir, |
191 | dentry->d_name.len); | |
192 | err = PTR_ERR(newdentry); | |
193 | if (IS_ERR(newdentry)) | |
194 | goto out_unlock; | |
195 | err = ovl_create_real(udir, newdentry, stat, link, hardlink, false); | |
196 | if (err) | |
197 | goto out_dput; | |
198 | ||
51f7e52d | 199 | ovl_instantiate(dentry, inode, newdentry, !!hardlink); |
e9be9d5e MS |
200 | newdentry = NULL; |
201 | out_dput: | |
202 | dput(newdentry); | |
203 | out_unlock: | |
5955102c | 204 | inode_unlock(udir); |
e9be9d5e MS |
205 | return err; |
206 | } | |
207 | ||
208 | static int ovl_lock_rename_workdir(struct dentry *workdir, | |
209 | struct dentry *upperdir) | |
210 | { | |
211 | /* Workdir should not be the same as upperdir */ | |
212 | if (workdir == upperdir) | |
213 | goto err; | |
214 | ||
215 | /* Workdir should not be subdir of upperdir and vice versa */ | |
216 | if (lock_rename(workdir, upperdir) != NULL) | |
217 | goto err_unlock; | |
218 | ||
219 | return 0; | |
220 | ||
221 | err_unlock: | |
222 | unlock_rename(workdir, upperdir); | |
223 | err: | |
224 | pr_err("overlayfs: failed to lock workdir+upperdir\n"); | |
225 | return -EIO; | |
226 | } | |
227 | ||
228 | static struct dentry *ovl_clear_empty(struct dentry *dentry, | |
229 | struct list_head *list) | |
230 | { | |
231 | struct dentry *workdir = ovl_workdir(dentry); | |
232 | struct inode *wdir = workdir->d_inode; | |
233 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
234 | struct inode *udir = upperdir->d_inode; | |
235 | struct path upperpath; | |
236 | struct dentry *upper; | |
237 | struct dentry *opaquedir; | |
238 | struct kstat stat; | |
239 | int err; | |
240 | ||
cc6f67bc MS |
241 | if (WARN_ON(!workdir)) |
242 | return ERR_PTR(-EROFS); | |
243 | ||
e9be9d5e MS |
244 | err = ovl_lock_rename_workdir(workdir, upperdir); |
245 | if (err) | |
246 | goto out; | |
247 | ||
248 | ovl_path_upper(dentry, &upperpath); | |
249 | err = vfs_getattr(&upperpath, &stat); | |
250 | if (err) | |
251 | goto out_unlock; | |
252 | ||
253 | err = -ESTALE; | |
254 | if (!S_ISDIR(stat.mode)) | |
255 | goto out_unlock; | |
256 | upper = upperpath.dentry; | |
257 | if (upper->d_parent->d_inode != udir) | |
258 | goto out_unlock; | |
259 | ||
260 | opaquedir = ovl_lookup_temp(workdir, dentry); | |
261 | err = PTR_ERR(opaquedir); | |
262 | if (IS_ERR(opaquedir)) | |
263 | goto out_unlock; | |
264 | ||
265 | err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true); | |
266 | if (err) | |
267 | goto out_dput; | |
268 | ||
269 | err = ovl_copy_xattr(upper, opaquedir); | |
270 | if (err) | |
271 | goto out_cleanup; | |
272 | ||
273 | err = ovl_set_opaque(opaquedir); | |
274 | if (err) | |
275 | goto out_cleanup; | |
276 | ||
5955102c | 277 | inode_lock(opaquedir->d_inode); |
e9be9d5e | 278 | err = ovl_set_attr(opaquedir, &stat); |
5955102c | 279 | inode_unlock(opaquedir->d_inode); |
e9be9d5e MS |
280 | if (err) |
281 | goto out_cleanup; | |
282 | ||
283 | err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE); | |
284 | if (err) | |
285 | goto out_cleanup; | |
286 | ||
287 | ovl_cleanup_whiteouts(upper, list); | |
288 | ovl_cleanup(wdir, upper); | |
289 | unlock_rename(workdir, upperdir); | |
290 | ||
291 | /* dentry's upper doesn't match now, get rid of it */ | |
292 | d_drop(dentry); | |
293 | ||
294 | return opaquedir; | |
295 | ||
296 | out_cleanup: | |
297 | ovl_cleanup(wdir, opaquedir); | |
298 | out_dput: | |
299 | dput(opaquedir); | |
300 | out_unlock: | |
301 | unlock_rename(workdir, upperdir); | |
302 | out: | |
303 | return ERR_PTR(err); | |
304 | } | |
305 | ||
a105d685 | 306 | static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry) |
e9be9d5e MS |
307 | { |
308 | int err; | |
309 | struct dentry *ret = NULL; | |
30c17ebf | 310 | enum ovl_path_type type = ovl_path_type(dentry); |
e9be9d5e MS |
311 | LIST_HEAD(list); |
312 | ||
313 | err = ovl_check_empty_dir(dentry, &list); | |
30c17ebf | 314 | if (err) { |
e9be9d5e | 315 | ret = ERR_PTR(err); |
30c17ebf | 316 | goto out_free; |
a105d685 | 317 | } |
e9be9d5e | 318 | |
30c17ebf MS |
319 | /* |
320 | * When removing an empty opaque directory, then it makes no sense to | |
321 | * replace it with an exact replica of itself. | |
322 | * | |
323 | * If no upperdentry then skip clearing whiteouts. | |
324 | * | |
325 | * Can race with copy-up, since we don't hold the upperdir mutex. | |
326 | * Doesn't matter, since copy-up can't create a non-empty directory | |
327 | * from an empty one. | |
328 | */ | |
329 | if (OVL_TYPE_UPPER(type) && OVL_TYPE_MERGE(type)) | |
330 | ret = ovl_clear_empty(dentry, &list); | |
331 | ||
332 | out_free: | |
e9be9d5e MS |
333 | ovl_cache_free(&list); |
334 | ||
335 | return ret; | |
336 | } | |
337 | ||
338 | static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, | |
339 | struct kstat *stat, const char *link, | |
340 | struct dentry *hardlink) | |
341 | { | |
342 | struct dentry *workdir = ovl_workdir(dentry); | |
343 | struct inode *wdir = workdir->d_inode; | |
344 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
345 | struct inode *udir = upperdir->d_inode; | |
346 | struct dentry *upper; | |
347 | struct dentry *newdentry; | |
348 | int err; | |
349 | ||
cc6f67bc MS |
350 | if (WARN_ON(!workdir)) |
351 | return -EROFS; | |
352 | ||
e9be9d5e MS |
353 | err = ovl_lock_rename_workdir(workdir, upperdir); |
354 | if (err) | |
355 | goto out; | |
356 | ||
357 | newdentry = ovl_lookup_temp(workdir, dentry); | |
358 | err = PTR_ERR(newdentry); | |
359 | if (IS_ERR(newdentry)) | |
360 | goto out_unlock; | |
361 | ||
362 | upper = lookup_one_len(dentry->d_name.name, upperdir, | |
363 | dentry->d_name.len); | |
364 | err = PTR_ERR(upper); | |
365 | if (IS_ERR(upper)) | |
366 | goto out_dput; | |
367 | ||
368 | err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true); | |
369 | if (err) | |
370 | goto out_dput2; | |
371 | ||
bb0d2b8a MS |
372 | /* |
373 | * mode could have been mutilated due to umask (e.g. sgid directory) | |
374 | */ | |
51f7e52d MS |
375 | if (!hardlink && |
376 | !S_ISLNK(stat->mode) && newdentry->d_inode->i_mode != stat->mode) { | |
bb0d2b8a MS |
377 | struct iattr attr = { |
378 | .ia_valid = ATTR_MODE, | |
379 | .ia_mode = stat->mode, | |
380 | }; | |
381 | inode_lock(newdentry->d_inode); | |
382 | err = notify_change(newdentry, &attr, NULL); | |
383 | inode_unlock(newdentry->d_inode); | |
384 | if (err) | |
385 | goto out_cleanup; | |
386 | } | |
387 | ||
51f7e52d | 388 | if (!hardlink && S_ISDIR(stat->mode)) { |
e9be9d5e MS |
389 | err = ovl_set_opaque(newdentry); |
390 | if (err) | |
391 | goto out_cleanup; | |
392 | ||
393 | err = ovl_do_rename(wdir, newdentry, udir, upper, | |
394 | RENAME_EXCHANGE); | |
395 | if (err) | |
396 | goto out_cleanup; | |
397 | ||
398 | ovl_cleanup(wdir, upper); | |
399 | } else { | |
400 | err = ovl_do_rename(wdir, newdentry, udir, upper, 0); | |
401 | if (err) | |
402 | goto out_cleanup; | |
403 | } | |
51f7e52d | 404 | ovl_instantiate(dentry, inode, newdentry, !!hardlink); |
e9be9d5e MS |
405 | newdentry = NULL; |
406 | out_dput2: | |
407 | dput(upper); | |
408 | out_dput: | |
409 | dput(newdentry); | |
410 | out_unlock: | |
411 | unlock_rename(workdir, upperdir); | |
412 | out: | |
413 | return err; | |
414 | ||
415 | out_cleanup: | |
416 | ovl_cleanup(wdir, newdentry); | |
417 | goto out_dput2; | |
418 | } | |
419 | ||
51f7e52d MS |
420 | static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, |
421 | struct kstat *stat, const char *link, | |
422 | struct dentry *hardlink) | |
e9be9d5e MS |
423 | { |
424 | int err; | |
1175b6b8 VG |
425 | const struct cred *old_cred; |
426 | struct cred *override_cred; | |
e9be9d5e MS |
427 | |
428 | err = ovl_copy_up(dentry->d_parent); | |
429 | if (err) | |
51f7e52d | 430 | return err; |
bb0d2b8a | 431 | |
1175b6b8 VG |
432 | old_cred = ovl_override_creds(dentry->d_sb); |
433 | err = -ENOMEM; | |
434 | override_cred = prepare_creds(); | |
435 | if (override_cred) { | |
bb0d2b8a MS |
436 | override_cred->fsuid = inode->i_uid; |
437 | override_cred->fsgid = inode->i_gid; | |
2602625b VG |
438 | if (!hardlink) { |
439 | err = security_dentry_create_files_as(dentry, | |
440 | stat->mode, &dentry->d_name, old_cred, | |
441 | override_cred); | |
442 | if (err) { | |
443 | put_cred(override_cred); | |
444 | goto out_revert_creds; | |
445 | } | |
446 | } | |
1175b6b8 VG |
447 | put_cred(override_creds(override_cred)); |
448 | put_cred(override_cred); | |
449 | ||
450 | if (!ovl_dentry_is_opaque(dentry)) | |
51f7e52d | 451 | err = ovl_create_upper(dentry, inode, stat, link, |
1175b6b8 VG |
452 | hardlink); |
453 | else | |
51f7e52d | 454 | err = ovl_create_over_whiteout(dentry, inode, stat, |
1175b6b8 | 455 | link, hardlink); |
e9be9d5e | 456 | } |
2602625b | 457 | out_revert_creds: |
1175b6b8 | 458 | revert_creds(old_cred); |
bb0d2b8a MS |
459 | if (!err) { |
460 | struct inode *realinode = d_inode(ovl_dentry_upper(dentry)); | |
461 | ||
462 | WARN_ON(inode->i_mode != realinode->i_mode); | |
463 | WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid)); | |
464 | WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid)); | |
bb0d2b8a | 465 | } |
e9be9d5e MS |
466 | return err; |
467 | } | |
468 | ||
469 | static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, | |
470 | const char *link) | |
471 | { | |
472 | int err; | |
51f7e52d MS |
473 | struct inode *inode; |
474 | struct kstat stat = { | |
475 | .rdev = rdev, | |
476 | }; | |
e9be9d5e MS |
477 | |
478 | err = ovl_want_write(dentry); | |
51f7e52d MS |
479 | if (err) |
480 | goto out; | |
481 | ||
482 | err = -ENOMEM; | |
483 | inode = ovl_new_inode(dentry->d_sb, mode); | |
484 | if (!inode) | |
485 | goto out_drop_write; | |
486 | ||
487 | inode_init_owner(inode, dentry->d_parent->d_inode, mode); | |
488 | stat.mode = inode->i_mode; | |
489 | ||
490 | err = ovl_create_or_link(dentry, inode, &stat, link, NULL); | |
491 | if (err) | |
492 | iput(inode); | |
e9be9d5e | 493 | |
51f7e52d MS |
494 | out_drop_write: |
495 | ovl_drop_write(dentry); | |
496 | out: | |
e9be9d5e MS |
497 | return err; |
498 | } | |
499 | ||
500 | static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode, | |
501 | bool excl) | |
502 | { | |
503 | return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL); | |
504 | } | |
505 | ||
506 | static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) | |
507 | { | |
508 | return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL); | |
509 | } | |
510 | ||
511 | static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, | |
512 | dev_t rdev) | |
513 | { | |
514 | /* Don't allow creation of "whiteout" on overlay */ | |
515 | if (S_ISCHR(mode) && rdev == WHITEOUT_DEV) | |
516 | return -EPERM; | |
517 | ||
518 | return ovl_create_object(dentry, mode, rdev, NULL); | |
519 | } | |
520 | ||
521 | static int ovl_symlink(struct inode *dir, struct dentry *dentry, | |
522 | const char *link) | |
523 | { | |
524 | return ovl_create_object(dentry, S_IFLNK, 0, link); | |
525 | } | |
526 | ||
527 | static int ovl_link(struct dentry *old, struct inode *newdir, | |
528 | struct dentry *new) | |
529 | { | |
530 | int err; | |
51f7e52d | 531 | struct inode *inode; |
e9be9d5e MS |
532 | |
533 | err = ovl_want_write(old); | |
534 | if (err) | |
535 | goto out; | |
536 | ||
537 | err = ovl_copy_up(old); | |
538 | if (err) | |
539 | goto out_drop_write; | |
540 | ||
51f7e52d MS |
541 | inode = d_inode(old); |
542 | ihold(inode); | |
543 | ||
544 | err = ovl_create_or_link(new, inode, NULL, NULL, ovl_dentry_upper(old)); | |
545 | if (err) | |
546 | iput(inode); | |
e9be9d5e MS |
547 | |
548 | out_drop_write: | |
549 | ovl_drop_write(old); | |
550 | out: | |
551 | return err; | |
552 | } | |
553 | ||
a105d685 | 554 | static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir) |
e9be9d5e MS |
555 | { |
556 | struct dentry *workdir = ovl_workdir(dentry); | |
557 | struct inode *wdir = workdir->d_inode; | |
558 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
559 | struct inode *udir = upperdir->d_inode; | |
560 | struct dentry *whiteout; | |
561 | struct dentry *upper; | |
562 | struct dentry *opaquedir = NULL; | |
563 | int err; | |
cfc9fde0 | 564 | int flags = 0; |
e9be9d5e | 565 | |
cc6f67bc MS |
566 | if (WARN_ON(!workdir)) |
567 | return -EROFS; | |
568 | ||
d377c5eb | 569 | if (is_dir) { |
30c17ebf MS |
570 | opaquedir = ovl_check_empty_and_clear(dentry); |
571 | err = PTR_ERR(opaquedir); | |
572 | if (IS_ERR(opaquedir)) | |
573 | goto out; | |
e9be9d5e MS |
574 | } |
575 | ||
576 | err = ovl_lock_rename_workdir(workdir, upperdir); | |
577 | if (err) | |
578 | goto out_dput; | |
579 | ||
cfc9fde0 MP |
580 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
581 | dentry->d_name.len); | |
582 | err = PTR_ERR(upper); | |
583 | if (IS_ERR(upper)) | |
e9be9d5e MS |
584 | goto out_unlock; |
585 | ||
cfc9fde0 MP |
586 | err = -ESTALE; |
587 | if ((opaquedir && upper != opaquedir) || | |
588 | (!opaquedir && ovl_dentry_upper(dentry) && | |
589 | upper != ovl_dentry_upper(dentry))) { | |
590 | goto out_dput_upper; | |
591 | } | |
e9be9d5e | 592 | |
cfc9fde0 MP |
593 | whiteout = ovl_whiteout(workdir, dentry); |
594 | err = PTR_ERR(whiteout); | |
595 | if (IS_ERR(whiteout)) | |
596 | goto out_dput_upper; | |
e9be9d5e | 597 | |
cfc9fde0 MP |
598 | if (d_is_dir(upper)) |
599 | flags = RENAME_EXCHANGE; | |
e9be9d5e | 600 | |
cfc9fde0 MP |
601 | err = ovl_do_rename(wdir, whiteout, udir, upper, flags); |
602 | if (err) | |
603 | goto kill_whiteout; | |
604 | if (flags) | |
605 | ovl_cleanup(wdir, upper); | |
e9be9d5e | 606 | |
e9be9d5e MS |
607 | ovl_dentry_version_inc(dentry->d_parent); |
608 | out_d_drop: | |
609 | d_drop(dentry); | |
610 | dput(whiteout); | |
cfc9fde0 MP |
611 | out_dput_upper: |
612 | dput(upper); | |
e9be9d5e MS |
613 | out_unlock: |
614 | unlock_rename(workdir, upperdir); | |
615 | out_dput: | |
616 | dput(opaquedir); | |
617 | out: | |
618 | return err; | |
619 | ||
620 | kill_whiteout: | |
621 | ovl_cleanup(wdir, whiteout); | |
622 | goto out_d_drop; | |
623 | } | |
624 | ||
625 | static int ovl_remove_upper(struct dentry *dentry, bool is_dir) | |
626 | { | |
627 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
628 | struct inode *dir = upperdir->d_inode; | |
11f37104 | 629 | struct dentry *upper; |
e9be9d5e MS |
630 | int err; |
631 | ||
5955102c | 632 | inode_lock_nested(dir, I_MUTEX_PARENT); |
11f37104 MS |
633 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
634 | dentry->d_name.len); | |
635 | err = PTR_ERR(upper); | |
636 | if (IS_ERR(upper)) | |
637 | goto out_unlock; | |
638 | ||
e9be9d5e | 639 | err = -ESTALE; |
11f37104 | 640 | if (upper == ovl_dentry_upper(dentry)) { |
e9be9d5e MS |
641 | if (is_dir) |
642 | err = vfs_rmdir(dir, upper); | |
643 | else | |
644 | err = vfs_unlink(dir, upper, NULL); | |
e9be9d5e MS |
645 | ovl_dentry_version_inc(dentry->d_parent); |
646 | } | |
11f37104 | 647 | dput(upper); |
e9be9d5e MS |
648 | |
649 | /* | |
650 | * Keeping this dentry hashed would mean having to release | |
651 | * upperpath/lowerpath, which could only be done if we are the | |
652 | * sole user of this dentry. Too tricky... Just unhash for | |
653 | * now. | |
654 | */ | |
ce9113bb RW |
655 | if (!err) |
656 | d_drop(dentry); | |
11f37104 | 657 | out_unlock: |
5955102c | 658 | inode_unlock(dir); |
e9be9d5e MS |
659 | |
660 | return err; | |
661 | } | |
662 | ||
663 | static inline int ovl_check_sticky(struct dentry *dentry) | |
664 | { | |
665 | struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode; | |
666 | struct inode *inode = ovl_dentry_real(dentry)->d_inode; | |
667 | ||
668 | if (check_sticky(dir, inode)) | |
669 | return -EPERM; | |
670 | ||
671 | return 0; | |
672 | } | |
673 | ||
674 | static int ovl_do_remove(struct dentry *dentry, bool is_dir) | |
675 | { | |
676 | enum ovl_path_type type; | |
677 | int err; | |
1175b6b8 VG |
678 | const struct cred *old_cred; |
679 | ||
e9be9d5e MS |
680 | |
681 | err = ovl_check_sticky(dentry); | |
682 | if (err) | |
683 | goto out; | |
684 | ||
685 | err = ovl_want_write(dentry); | |
686 | if (err) | |
687 | goto out; | |
688 | ||
689 | err = ovl_copy_up(dentry->d_parent); | |
690 | if (err) | |
691 | goto out_drop_write; | |
692 | ||
693 | type = ovl_path_type(dentry); | |
e9be9d5e | 694 | |
1175b6b8 VG |
695 | old_cred = ovl_override_creds(dentry->d_sb); |
696 | if (OVL_TYPE_PURE_UPPER(type)) | |
697 | err = ovl_remove_upper(dentry, is_dir); | |
698 | else | |
a105d685 | 699 | err = ovl_remove_and_whiteout(dentry, is_dir); |
1175b6b8 | 700 | revert_creds(old_cred); |
dbc816d0 MS |
701 | if (!err) { |
702 | if (is_dir) | |
703 | clear_nlink(dentry->d_inode); | |
704 | else | |
705 | drop_nlink(dentry->d_inode); | |
706 | } | |
e9be9d5e MS |
707 | out_drop_write: |
708 | ovl_drop_write(dentry); | |
709 | out: | |
710 | return err; | |
711 | } | |
712 | ||
713 | static int ovl_unlink(struct inode *dir, struct dentry *dentry) | |
714 | { | |
715 | return ovl_do_remove(dentry, false); | |
716 | } | |
717 | ||
718 | static int ovl_rmdir(struct inode *dir, struct dentry *dentry) | |
719 | { | |
720 | return ovl_do_remove(dentry, true); | |
721 | } | |
722 | ||
723 | static int ovl_rename2(struct inode *olddir, struct dentry *old, | |
724 | struct inode *newdir, struct dentry *new, | |
725 | unsigned int flags) | |
726 | { | |
727 | int err; | |
728 | enum ovl_path_type old_type; | |
729 | enum ovl_path_type new_type; | |
730 | struct dentry *old_upperdir; | |
731 | struct dentry *new_upperdir; | |
732 | struct dentry *olddentry; | |
733 | struct dentry *newdentry; | |
734 | struct dentry *trap; | |
735 | bool old_opaque; | |
736 | bool new_opaque; | |
e9be9d5e MS |
737 | bool cleanup_whiteout = false; |
738 | bool overwrite = !(flags & RENAME_EXCHANGE); | |
e36cb0b8 | 739 | bool is_dir = d_is_dir(old); |
e9be9d5e MS |
740 | bool new_is_dir = false; |
741 | struct dentry *opaquedir = NULL; | |
742 | const struct cred *old_cred = NULL; | |
e9be9d5e MS |
743 | |
744 | err = -EINVAL; | |
745 | if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) | |
746 | goto out; | |
747 | ||
748 | flags &= ~RENAME_NOREPLACE; | |
749 | ||
750 | err = ovl_check_sticky(old); | |
751 | if (err) | |
752 | goto out; | |
753 | ||
754 | /* Don't copy up directory trees */ | |
755 | old_type = ovl_path_type(old); | |
756 | err = -EXDEV; | |
1afaba1e | 757 | if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir) |
e9be9d5e MS |
758 | goto out; |
759 | ||
760 | if (new->d_inode) { | |
761 | err = ovl_check_sticky(new); | |
762 | if (err) | |
763 | goto out; | |
764 | ||
e36cb0b8 | 765 | if (d_is_dir(new)) |
e9be9d5e MS |
766 | new_is_dir = true; |
767 | ||
768 | new_type = ovl_path_type(new); | |
769 | err = -EXDEV; | |
1afaba1e | 770 | if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) |
e9be9d5e MS |
771 | goto out; |
772 | ||
773 | err = 0; | |
1afaba1e | 774 | if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) { |
e9be9d5e MS |
775 | if (ovl_dentry_lower(old)->d_inode == |
776 | ovl_dentry_lower(new)->d_inode) | |
777 | goto out; | |
778 | } | |
1afaba1e | 779 | if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) { |
e9be9d5e MS |
780 | if (ovl_dentry_upper(old)->d_inode == |
781 | ovl_dentry_upper(new)->d_inode) | |
782 | goto out; | |
783 | } | |
784 | } else { | |
785 | if (ovl_dentry_is_opaque(new)) | |
1afaba1e | 786 | new_type = __OVL_PATH_UPPER; |
e9be9d5e | 787 | else |
1afaba1e | 788 | new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE; |
e9be9d5e MS |
789 | } |
790 | ||
791 | err = ovl_want_write(old); | |
792 | if (err) | |
793 | goto out; | |
794 | ||
795 | err = ovl_copy_up(old); | |
796 | if (err) | |
797 | goto out_drop_write; | |
798 | ||
799 | err = ovl_copy_up(new->d_parent); | |
800 | if (err) | |
801 | goto out_drop_write; | |
802 | if (!overwrite) { | |
803 | err = ovl_copy_up(new); | |
804 | if (err) | |
805 | goto out_drop_write; | |
806 | } | |
807 | ||
1afaba1e MS |
808 | old_opaque = !OVL_TYPE_PURE_UPPER(old_type); |
809 | new_opaque = !OVL_TYPE_PURE_UPPER(new_type); | |
e9be9d5e | 810 | |
1175b6b8 | 811 | old_cred = ovl_override_creds(old->d_sb); |
e9be9d5e | 812 | |
1afaba1e | 813 | if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) { |
a105d685 | 814 | opaquedir = ovl_check_empty_and_clear(new); |
e9be9d5e MS |
815 | err = PTR_ERR(opaquedir); |
816 | if (IS_ERR(opaquedir)) { | |
817 | opaquedir = NULL; | |
818 | goto out_revert_creds; | |
819 | } | |
820 | } | |
821 | ||
822 | if (overwrite) { | |
823 | if (old_opaque) { | |
824 | if (new->d_inode || !new_opaque) { | |
825 | /* Whiteout source */ | |
826 | flags |= RENAME_WHITEOUT; | |
827 | } else { | |
828 | /* Switch whiteouts */ | |
829 | flags |= RENAME_EXCHANGE; | |
830 | } | |
831 | } else if (is_dir && !new->d_inode && new_opaque) { | |
832 | flags |= RENAME_EXCHANGE; | |
833 | cleanup_whiteout = true; | |
834 | } | |
835 | } | |
836 | ||
837 | old_upperdir = ovl_dentry_upper(old->d_parent); | |
838 | new_upperdir = ovl_dentry_upper(new->d_parent); | |
839 | ||
840 | trap = lock_rename(new_upperdir, old_upperdir); | |
841 | ||
11f37104 MS |
842 | |
843 | olddentry = lookup_one_len(old->d_name.name, old_upperdir, | |
844 | old->d_name.len); | |
845 | err = PTR_ERR(olddentry); | |
846 | if (IS_ERR(olddentry)) | |
847 | goto out_unlock; | |
848 | ||
849 | err = -ESTALE; | |
850 | if (olddentry != ovl_dentry_upper(old)) | |
851 | goto out_dput_old; | |
852 | ||
853 | newdentry = lookup_one_len(new->d_name.name, new_upperdir, | |
854 | new->d_name.len); | |
855 | err = PTR_ERR(newdentry); | |
856 | if (IS_ERR(newdentry)) | |
857 | goto out_dput_old; | |
858 | ||
859 | err = -ESTALE; | |
860 | if (ovl_dentry_upper(new)) { | |
e9be9d5e | 861 | if (opaquedir) { |
11f37104 MS |
862 | if (newdentry != opaquedir) |
863 | goto out_dput; | |
e9be9d5e | 864 | } else { |
11f37104 MS |
865 | if (newdentry != ovl_dentry_upper(new)) |
866 | goto out_dput; | |
e9be9d5e MS |
867 | } |
868 | } else { | |
11f37104 MS |
869 | if (!d_is_negative(newdentry) && |
870 | (!new_opaque || !ovl_is_whiteout(newdentry))) | |
871 | goto out_dput; | |
e9be9d5e MS |
872 | } |
873 | ||
e9be9d5e MS |
874 | if (olddentry == trap) |
875 | goto out_dput; | |
876 | if (newdentry == trap) | |
877 | goto out_dput; | |
878 | ||
879 | if (is_dir && !old_opaque && new_opaque) { | |
880 | err = ovl_set_opaque(olddentry); | |
881 | if (err) | |
882 | goto out_dput; | |
883 | } | |
884 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) { | |
885 | err = ovl_set_opaque(newdentry); | |
886 | if (err) | |
887 | goto out_dput; | |
888 | } | |
889 | ||
890 | if (old_opaque || new_opaque) { | |
891 | err = ovl_do_rename(old_upperdir->d_inode, olddentry, | |
892 | new_upperdir->d_inode, newdentry, | |
893 | flags); | |
894 | } else { | |
895 | /* No debug for the plain case */ | |
896 | BUG_ON(flags & ~RENAME_EXCHANGE); | |
897 | err = vfs_rename(old_upperdir->d_inode, olddentry, | |
898 | new_upperdir->d_inode, newdentry, | |
899 | NULL, flags); | |
900 | } | |
901 | ||
902 | if (err) { | |
903 | if (is_dir && !old_opaque && new_opaque) | |
904 | ovl_remove_opaque(olddentry); | |
905 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) | |
906 | ovl_remove_opaque(newdentry); | |
907 | goto out_dput; | |
908 | } | |
909 | ||
910 | if (is_dir && old_opaque && !new_opaque) | |
911 | ovl_remove_opaque(olddentry); | |
912 | if (!overwrite && new_is_dir && !old_opaque && new_opaque) | |
913 | ovl_remove_opaque(newdentry); | |
914 | ||
45d11738 KK |
915 | /* |
916 | * Old dentry now lives in different location. Dentries in | |
917 | * lowerstack are stale. We cannot drop them here because | |
918 | * access to them is lockless. This could be only pure upper | |
919 | * or opaque directory - numlower is zero. Or upper non-dir | |
920 | * entry - its pureness is tracked by flag opaque. | |
921 | */ | |
e9be9d5e MS |
922 | if (old_opaque != new_opaque) { |
923 | ovl_dentry_set_opaque(old, new_opaque); | |
924 | if (!overwrite) | |
925 | ovl_dentry_set_opaque(new, old_opaque); | |
926 | } | |
927 | ||
928 | if (cleanup_whiteout) | |
929 | ovl_cleanup(old_upperdir->d_inode, newdentry); | |
930 | ||
931 | ovl_dentry_version_inc(old->d_parent); | |
932 | ovl_dentry_version_inc(new->d_parent); | |
933 | ||
934 | out_dput: | |
935 | dput(newdentry); | |
11f37104 MS |
936 | out_dput_old: |
937 | dput(olddentry); | |
e9be9d5e MS |
938 | out_unlock: |
939 | unlock_rename(new_upperdir, old_upperdir); | |
940 | out_revert_creds: | |
1175b6b8 | 941 | revert_creds(old_cred); |
e9be9d5e MS |
942 | out_drop_write: |
943 | ovl_drop_write(old); | |
944 | out: | |
945 | dput(opaquedir); | |
946 | return err; | |
947 | } | |
948 | ||
949 | const struct inode_operations ovl_dir_inode_operations = { | |
950 | .lookup = ovl_lookup, | |
951 | .mkdir = ovl_mkdir, | |
952 | .symlink = ovl_symlink, | |
953 | .unlink = ovl_unlink, | |
954 | .rmdir = ovl_rmdir, | |
955 | .rename2 = ovl_rename2, | |
956 | .link = ovl_link, | |
957 | .setattr = ovl_setattr, | |
958 | .create = ovl_create, | |
959 | .mknod = ovl_mknod, | |
960 | .permission = ovl_permission, | |
961 | .getattr = ovl_dir_getattr, | |
d837a49b | 962 | .setxattr = generic_setxattr, |
e9be9d5e MS |
963 | .getxattr = ovl_getxattr, |
964 | .listxattr = ovl_listxattr, | |
965 | .removexattr = ovl_removexattr, | |
39a25b2b | 966 | .get_acl = ovl_get_acl, |
d719e8f2 | 967 | .update_time = ovl_update_time, |
e9be9d5e | 968 | }; |