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