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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> | |
38b25697 MS |
15 | #include <linux/posix_acl.h> |
16 | #include <linux/posix_acl_xattr.h> | |
6a45b362 | 17 | #include <linux/atomic.h> |
e9be9d5e MS |
18 | #include "overlayfs.h" |
19 | ||
20 | void ovl_cleanup(struct inode *wdir, struct dentry *wdentry) | |
21 | { | |
22 | int err; | |
23 | ||
24 | dget(wdentry); | |
e36cb0b8 | 25 | if (d_is_dir(wdentry)) |
e9be9d5e MS |
26 | err = ovl_do_rmdir(wdir, wdentry); |
27 | else | |
28 | err = ovl_do_unlink(wdir, wdentry); | |
29 | dput(wdentry); | |
30 | ||
31 | if (err) { | |
32 | pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n", | |
33 | wdentry, err); | |
34 | } | |
35 | } | |
36 | ||
37 | struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry) | |
38 | { | |
39 | struct dentry *temp; | |
40 | char name[20]; | |
6a45b362 | 41 | static atomic_t temp_id = ATOMIC_INIT(0); |
e9be9d5e | 42 | |
6a45b362 RW |
43 | /* counter is allowed to wrap, since temp dentries are ephemeral */ |
44 | snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id)); | |
e9be9d5e MS |
45 | |
46 | temp = lookup_one_len(name, workdir, strlen(name)); | |
47 | if (!IS_ERR(temp) && temp->d_inode) { | |
48 | pr_err("overlayfs: workdir/%s already exists\n", name); | |
49 | dput(temp); | |
50 | temp = ERR_PTR(-EIO); | |
51 | } | |
52 | ||
53 | return temp; | |
54 | } | |
55 | ||
56 | /* caller holds i_mutex on workdir */ | |
57 | static struct dentry *ovl_whiteout(struct dentry *workdir, | |
58 | struct dentry *dentry) | |
59 | { | |
60 | int err; | |
61 | struct dentry *whiteout; | |
62 | struct inode *wdir = workdir->d_inode; | |
63 | ||
64 | whiteout = ovl_lookup_temp(workdir, dentry); | |
65 | if (IS_ERR(whiteout)) | |
66 | return whiteout; | |
67 | ||
68 | err = ovl_do_whiteout(wdir, whiteout); | |
69 | if (err) { | |
70 | dput(whiteout); | |
71 | whiteout = ERR_PTR(err); | |
72 | } | |
73 | ||
74 | return whiteout; | |
75 | } | |
76 | ||
77 | int ovl_create_real(struct inode *dir, struct dentry *newdentry, | |
78 | struct kstat *stat, const char *link, | |
79 | struct dentry *hardlink, bool debug) | |
80 | { | |
81 | int err; | |
82 | ||
83 | if (newdentry->d_inode) | |
84 | return -ESTALE; | |
85 | ||
86 | if (hardlink) { | |
87 | err = ovl_do_link(hardlink, dir, newdentry, debug); | |
88 | } else { | |
89 | switch (stat->mode & S_IFMT) { | |
90 | case S_IFREG: | |
91 | err = ovl_do_create(dir, newdentry, stat->mode, debug); | |
92 | break; | |
93 | ||
94 | case S_IFDIR: | |
95 | err = ovl_do_mkdir(dir, newdentry, stat->mode, debug); | |
96 | break; | |
97 | ||
98 | case S_IFCHR: | |
99 | case S_IFBLK: | |
100 | case S_IFIFO: | |
101 | case S_IFSOCK: | |
102 | err = ovl_do_mknod(dir, newdentry, | |
103 | stat->mode, stat->rdev, debug); | |
104 | break; | |
105 | ||
106 | case S_IFLNK: | |
107 | err = ovl_do_symlink(dir, newdentry, link, debug); | |
108 | break; | |
109 | ||
110 | default: | |
111 | err = -EPERM; | |
112 | } | |
113 | } | |
114 | if (!err && WARN_ON(!newdentry->d_inode)) { | |
115 | /* | |
116 | * Not quite sure if non-instantiated dentry is legal or not. | |
117 | * VFS doesn't seem to care so check and warn here. | |
118 | */ | |
119 | err = -ENOENT; | |
120 | } | |
121 | return err; | |
122 | } | |
123 | ||
124 | static int ovl_set_opaque(struct dentry *upperdentry) | |
125 | { | |
cead89bb | 126 | return ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0); |
e9be9d5e MS |
127 | } |
128 | ||
129 | static void ovl_remove_opaque(struct dentry *upperdentry) | |
130 | { | |
131 | int err; | |
132 | ||
cead89bb | 133 | err = ovl_do_removexattr(upperdentry, OVL_XATTR_OPAQUE); |
e9be9d5e MS |
134 | if (err) { |
135 | pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n", | |
136 | upperdentry->d_name.name, err); | |
137 | } | |
138 | } | |
139 | ||
140 | static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry, | |
141 | struct kstat *stat) | |
142 | { | |
143 | int err; | |
144 | enum ovl_path_type type; | |
145 | struct path realpath; | |
1175b6b8 | 146 | const struct cred *old_cred; |
e9be9d5e MS |
147 | |
148 | type = ovl_path_real(dentry, &realpath); | |
1175b6b8 | 149 | old_cred = ovl_override_creds(dentry->d_sb); |
e9be9d5e | 150 | err = vfs_getattr(&realpath, stat); |
1175b6b8 | 151 | revert_creds(old_cred); |
e9be9d5e MS |
152 | if (err) |
153 | return err; | |
154 | ||
155 | stat->dev = dentry->d_sb->s_dev; | |
156 | stat->ino = dentry->d_inode->i_ino; | |
157 | ||
158 | /* | |
159 | * It's probably not worth it to count subdirs to get the | |
160 | * correct link count. nlink=1 seems to pacify 'find' and | |
161 | * other utilities. | |
162 | */ | |
1afaba1e | 163 | if (OVL_TYPE_MERGE(type)) |
e9be9d5e MS |
164 | stat->nlink = 1; |
165 | ||
166 | return 0; | |
167 | } | |
168 | ||
72e48481 VG |
169 | /* Common operations required to be done after creation of file on upper */ |
170 | static void ovl_instantiate(struct dentry *dentry, struct inode *inode, | |
51f7e52d | 171 | struct dentry *newdentry, bool hardlink) |
72e48481 VG |
172 | { |
173 | ovl_dentry_version_inc(dentry->d_parent); | |
174 | ovl_dentry_update(dentry, newdentry); | |
51f7e52d MS |
175 | if (!hardlink) { |
176 | ovl_inode_update(inode, d_inode(newdentry)); | |
177 | ovl_copyattr(newdentry->d_inode, inode); | |
178 | } else { | |
179 | WARN_ON(ovl_inode_real(inode, NULL) != d_inode(newdentry)); | |
180 | inc_nlink(inode); | |
181 | } | |
72e48481 VG |
182 | d_instantiate(dentry, inode); |
183 | } | |
184 | ||
e9be9d5e MS |
185 | static int ovl_create_upper(struct dentry *dentry, struct inode *inode, |
186 | struct kstat *stat, const char *link, | |
187 | struct dentry *hardlink) | |
188 | { | |
189 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
190 | struct inode *udir = upperdir->d_inode; | |
191 | struct dentry *newdentry; | |
192 | int err; | |
193 | ||
38b25697 MS |
194 | if (!hardlink && !IS_POSIXACL(udir)) |
195 | stat->mode &= ~current_umask(); | |
196 | ||
5955102c | 197 | inode_lock_nested(udir, I_MUTEX_PARENT); |
e9be9d5e MS |
198 | newdentry = lookup_one_len(dentry->d_name.name, upperdir, |
199 | dentry->d_name.len); | |
200 | err = PTR_ERR(newdentry); | |
201 | if (IS_ERR(newdentry)) | |
202 | goto out_unlock; | |
203 | err = ovl_create_real(udir, newdentry, stat, link, hardlink, false); | |
204 | if (err) | |
205 | goto out_dput; | |
206 | ||
51f7e52d | 207 | ovl_instantiate(dentry, inode, newdentry, !!hardlink); |
e9be9d5e MS |
208 | newdentry = NULL; |
209 | out_dput: | |
210 | dput(newdentry); | |
211 | out_unlock: | |
5955102c | 212 | inode_unlock(udir); |
e9be9d5e MS |
213 | return err; |
214 | } | |
215 | ||
216 | static int ovl_lock_rename_workdir(struct dentry *workdir, | |
217 | struct dentry *upperdir) | |
218 | { | |
219 | /* Workdir should not be the same as upperdir */ | |
220 | if (workdir == upperdir) | |
221 | goto err; | |
222 | ||
223 | /* Workdir should not be subdir of upperdir and vice versa */ | |
224 | if (lock_rename(workdir, upperdir) != NULL) | |
225 | goto err_unlock; | |
226 | ||
227 | return 0; | |
228 | ||
229 | err_unlock: | |
230 | unlock_rename(workdir, upperdir); | |
231 | err: | |
232 | pr_err("overlayfs: failed to lock workdir+upperdir\n"); | |
233 | return -EIO; | |
234 | } | |
235 | ||
236 | static struct dentry *ovl_clear_empty(struct dentry *dentry, | |
237 | struct list_head *list) | |
238 | { | |
239 | struct dentry *workdir = ovl_workdir(dentry); | |
240 | struct inode *wdir = workdir->d_inode; | |
241 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
242 | struct inode *udir = upperdir->d_inode; | |
243 | struct path upperpath; | |
244 | struct dentry *upper; | |
245 | struct dentry *opaquedir; | |
246 | struct kstat stat; | |
247 | int err; | |
248 | ||
cc6f67bc MS |
249 | if (WARN_ON(!workdir)) |
250 | return ERR_PTR(-EROFS); | |
251 | ||
e9be9d5e MS |
252 | err = ovl_lock_rename_workdir(workdir, upperdir); |
253 | if (err) | |
254 | goto out; | |
255 | ||
256 | ovl_path_upper(dentry, &upperpath); | |
257 | err = vfs_getattr(&upperpath, &stat); | |
258 | if (err) | |
259 | goto out_unlock; | |
260 | ||
261 | err = -ESTALE; | |
262 | if (!S_ISDIR(stat.mode)) | |
263 | goto out_unlock; | |
264 | upper = upperpath.dentry; | |
265 | if (upper->d_parent->d_inode != udir) | |
266 | goto out_unlock; | |
267 | ||
268 | opaquedir = ovl_lookup_temp(workdir, dentry); | |
269 | err = PTR_ERR(opaquedir); | |
270 | if (IS_ERR(opaquedir)) | |
271 | goto out_unlock; | |
272 | ||
273 | err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true); | |
274 | if (err) | |
275 | goto out_dput; | |
276 | ||
277 | err = ovl_copy_xattr(upper, opaquedir); | |
278 | if (err) | |
279 | goto out_cleanup; | |
280 | ||
281 | err = ovl_set_opaque(opaquedir); | |
282 | if (err) | |
283 | goto out_cleanup; | |
284 | ||
5955102c | 285 | inode_lock(opaquedir->d_inode); |
e9be9d5e | 286 | err = ovl_set_attr(opaquedir, &stat); |
5955102c | 287 | inode_unlock(opaquedir->d_inode); |
e9be9d5e MS |
288 | if (err) |
289 | goto out_cleanup; | |
290 | ||
291 | err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE); | |
292 | if (err) | |
293 | goto out_cleanup; | |
294 | ||
295 | ovl_cleanup_whiteouts(upper, list); | |
296 | ovl_cleanup(wdir, upper); | |
297 | unlock_rename(workdir, upperdir); | |
298 | ||
299 | /* dentry's upper doesn't match now, get rid of it */ | |
300 | d_drop(dentry); | |
301 | ||
302 | return opaquedir; | |
303 | ||
304 | out_cleanup: | |
305 | ovl_cleanup(wdir, opaquedir); | |
306 | out_dput: | |
307 | dput(opaquedir); | |
308 | out_unlock: | |
309 | unlock_rename(workdir, upperdir); | |
310 | out: | |
311 | return ERR_PTR(err); | |
312 | } | |
313 | ||
a105d685 | 314 | static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry) |
e9be9d5e MS |
315 | { |
316 | int err; | |
317 | struct dentry *ret = NULL; | |
30c17ebf | 318 | enum ovl_path_type type = ovl_path_type(dentry); |
e9be9d5e MS |
319 | LIST_HEAD(list); |
320 | ||
321 | err = ovl_check_empty_dir(dentry, &list); | |
30c17ebf | 322 | if (err) { |
e9be9d5e | 323 | ret = ERR_PTR(err); |
30c17ebf | 324 | goto out_free; |
a105d685 | 325 | } |
e9be9d5e | 326 | |
30c17ebf MS |
327 | /* |
328 | * When removing an empty opaque directory, then it makes no sense to | |
329 | * replace it with an exact replica of itself. | |
330 | * | |
331 | * If no upperdentry then skip clearing whiteouts. | |
332 | * | |
333 | * Can race with copy-up, since we don't hold the upperdir mutex. | |
334 | * Doesn't matter, since copy-up can't create a non-empty directory | |
335 | * from an empty one. | |
336 | */ | |
337 | if (OVL_TYPE_UPPER(type) && OVL_TYPE_MERGE(type)) | |
338 | ret = ovl_clear_empty(dentry, &list); | |
339 | ||
340 | out_free: | |
e9be9d5e MS |
341 | ovl_cache_free(&list); |
342 | ||
343 | return ret; | |
344 | } | |
345 | ||
38b25697 MS |
346 | static int ovl_set_upper_acl(struct dentry *upperdentry, const char *name, |
347 | const struct posix_acl *acl) | |
348 | { | |
349 | void *buffer; | |
350 | size_t size; | |
351 | int err; | |
352 | ||
353 | if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl) | |
354 | return 0; | |
355 | ||
356 | size = posix_acl_to_xattr(NULL, acl, NULL, 0); | |
357 | buffer = kmalloc(size, GFP_KERNEL); | |
358 | if (!buffer) | |
359 | return -ENOMEM; | |
360 | ||
361 | size = posix_acl_to_xattr(&init_user_ns, acl, buffer, size); | |
362 | err = size; | |
363 | if (err < 0) | |
364 | goto out_free; | |
365 | ||
366 | err = vfs_setxattr(upperdentry, name, buffer, size, XATTR_CREATE); | |
367 | out_free: | |
368 | kfree(buffer); | |
369 | return err; | |
370 | } | |
371 | ||
e9be9d5e MS |
372 | static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, |
373 | struct kstat *stat, const char *link, | |
374 | struct dentry *hardlink) | |
375 | { | |
376 | struct dentry *workdir = ovl_workdir(dentry); | |
377 | struct inode *wdir = workdir->d_inode; | |
378 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
379 | struct inode *udir = upperdir->d_inode; | |
380 | struct dentry *upper; | |
381 | struct dentry *newdentry; | |
382 | int err; | |
38b25697 | 383 | struct posix_acl *acl, *default_acl; |
e9be9d5e | 384 | |
cc6f67bc MS |
385 | if (WARN_ON(!workdir)) |
386 | return -EROFS; | |
387 | ||
38b25697 MS |
388 | if (!hardlink) { |
389 | err = posix_acl_create(dentry->d_parent->d_inode, | |
390 | &stat->mode, &default_acl, &acl); | |
391 | if (err) | |
392 | return err; | |
393 | } | |
394 | ||
e9be9d5e MS |
395 | err = ovl_lock_rename_workdir(workdir, upperdir); |
396 | if (err) | |
397 | goto out; | |
398 | ||
399 | newdentry = ovl_lookup_temp(workdir, dentry); | |
400 | err = PTR_ERR(newdentry); | |
401 | if (IS_ERR(newdentry)) | |
402 | goto out_unlock; | |
403 | ||
404 | upper = lookup_one_len(dentry->d_name.name, upperdir, | |
405 | dentry->d_name.len); | |
406 | err = PTR_ERR(upper); | |
407 | if (IS_ERR(upper)) | |
408 | goto out_dput; | |
409 | ||
410 | err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true); | |
411 | if (err) | |
412 | goto out_dput2; | |
413 | ||
bb0d2b8a MS |
414 | /* |
415 | * mode could have been mutilated due to umask (e.g. sgid directory) | |
416 | */ | |
51f7e52d MS |
417 | if (!hardlink && |
418 | !S_ISLNK(stat->mode) && newdentry->d_inode->i_mode != stat->mode) { | |
bb0d2b8a MS |
419 | struct iattr attr = { |
420 | .ia_valid = ATTR_MODE, | |
421 | .ia_mode = stat->mode, | |
422 | }; | |
423 | inode_lock(newdentry->d_inode); | |
424 | err = notify_change(newdentry, &attr, NULL); | |
425 | inode_unlock(newdentry->d_inode); | |
426 | if (err) | |
427 | goto out_cleanup; | |
428 | } | |
38b25697 MS |
429 | if (!hardlink) { |
430 | err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS, | |
431 | acl); | |
432 | if (err) | |
433 | goto out_cleanup; | |
434 | ||
435 | err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT, | |
436 | default_acl); | |
437 | if (err) | |
438 | goto out_cleanup; | |
439 | } | |
bb0d2b8a | 440 | |
51f7e52d | 441 | if (!hardlink && S_ISDIR(stat->mode)) { |
e9be9d5e MS |
442 | err = ovl_set_opaque(newdentry); |
443 | if (err) | |
444 | goto out_cleanup; | |
445 | ||
446 | err = ovl_do_rename(wdir, newdentry, udir, upper, | |
447 | RENAME_EXCHANGE); | |
448 | if (err) | |
449 | goto out_cleanup; | |
450 | ||
451 | ovl_cleanup(wdir, upper); | |
452 | } else { | |
453 | err = ovl_do_rename(wdir, newdentry, udir, upper, 0); | |
454 | if (err) | |
455 | goto out_cleanup; | |
456 | } | |
51f7e52d | 457 | ovl_instantiate(dentry, inode, newdentry, !!hardlink); |
e9be9d5e MS |
458 | newdentry = NULL; |
459 | out_dput2: | |
460 | dput(upper); | |
461 | out_dput: | |
462 | dput(newdentry); | |
463 | out_unlock: | |
464 | unlock_rename(workdir, upperdir); | |
465 | out: | |
38b25697 MS |
466 | if (!hardlink) { |
467 | posix_acl_release(acl); | |
468 | posix_acl_release(default_acl); | |
469 | } | |
e9be9d5e MS |
470 | return err; |
471 | ||
472 | out_cleanup: | |
473 | ovl_cleanup(wdir, newdentry); | |
474 | goto out_dput2; | |
475 | } | |
476 | ||
51f7e52d MS |
477 | static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, |
478 | struct kstat *stat, const char *link, | |
479 | struct dentry *hardlink) | |
e9be9d5e MS |
480 | { |
481 | int err; | |
1175b6b8 VG |
482 | const struct cred *old_cred; |
483 | struct cred *override_cred; | |
e9be9d5e MS |
484 | |
485 | err = ovl_copy_up(dentry->d_parent); | |
486 | if (err) | |
51f7e52d | 487 | return err; |
bb0d2b8a | 488 | |
1175b6b8 VG |
489 | old_cred = ovl_override_creds(dentry->d_sb); |
490 | err = -ENOMEM; | |
491 | override_cred = prepare_creds(); | |
492 | if (override_cred) { | |
bb0d2b8a MS |
493 | override_cred->fsuid = inode->i_uid; |
494 | override_cred->fsgid = inode->i_gid; | |
2602625b VG |
495 | if (!hardlink) { |
496 | err = security_dentry_create_files_as(dentry, | |
497 | stat->mode, &dentry->d_name, old_cred, | |
498 | override_cred); | |
499 | if (err) { | |
500 | put_cred(override_cred); | |
501 | goto out_revert_creds; | |
502 | } | |
503 | } | |
1175b6b8 VG |
504 | put_cred(override_creds(override_cred)); |
505 | put_cred(override_cred); | |
506 | ||
c412ce49 | 507 | if (!ovl_dentry_is_whiteout(dentry)) |
51f7e52d | 508 | err = ovl_create_upper(dentry, inode, stat, link, |
1175b6b8 VG |
509 | hardlink); |
510 | else | |
51f7e52d | 511 | err = ovl_create_over_whiteout(dentry, inode, stat, |
1175b6b8 | 512 | link, hardlink); |
e9be9d5e | 513 | } |
2602625b | 514 | out_revert_creds: |
1175b6b8 | 515 | revert_creds(old_cred); |
bb0d2b8a MS |
516 | if (!err) { |
517 | struct inode *realinode = d_inode(ovl_dentry_upper(dentry)); | |
518 | ||
519 | WARN_ON(inode->i_mode != realinode->i_mode); | |
520 | WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid)); | |
521 | WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid)); | |
bb0d2b8a | 522 | } |
e9be9d5e MS |
523 | return err; |
524 | } | |
525 | ||
526 | static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, | |
527 | const char *link) | |
528 | { | |
529 | int err; | |
51f7e52d MS |
530 | struct inode *inode; |
531 | struct kstat stat = { | |
532 | .rdev = rdev, | |
533 | }; | |
e9be9d5e MS |
534 | |
535 | err = ovl_want_write(dentry); | |
51f7e52d MS |
536 | if (err) |
537 | goto out; | |
538 | ||
539 | err = -ENOMEM; | |
ca4c8a3a | 540 | inode = ovl_new_inode(dentry->d_sb, mode, rdev); |
51f7e52d MS |
541 | if (!inode) |
542 | goto out_drop_write; | |
543 | ||
544 | inode_init_owner(inode, dentry->d_parent->d_inode, mode); | |
545 | stat.mode = inode->i_mode; | |
546 | ||
547 | err = ovl_create_or_link(dentry, inode, &stat, link, NULL); | |
548 | if (err) | |
549 | iput(inode); | |
e9be9d5e | 550 | |
51f7e52d MS |
551 | out_drop_write: |
552 | ovl_drop_write(dentry); | |
553 | out: | |
e9be9d5e MS |
554 | return err; |
555 | } | |
556 | ||
557 | static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode, | |
558 | bool excl) | |
559 | { | |
560 | return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL); | |
561 | } | |
562 | ||
563 | static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) | |
564 | { | |
565 | return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL); | |
566 | } | |
567 | ||
568 | static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, | |
569 | dev_t rdev) | |
570 | { | |
571 | /* Don't allow creation of "whiteout" on overlay */ | |
572 | if (S_ISCHR(mode) && rdev == WHITEOUT_DEV) | |
573 | return -EPERM; | |
574 | ||
575 | return ovl_create_object(dentry, mode, rdev, NULL); | |
576 | } | |
577 | ||
578 | static int ovl_symlink(struct inode *dir, struct dentry *dentry, | |
579 | const char *link) | |
580 | { | |
581 | return ovl_create_object(dentry, S_IFLNK, 0, link); | |
582 | } | |
583 | ||
584 | static int ovl_link(struct dentry *old, struct inode *newdir, | |
585 | struct dentry *new) | |
586 | { | |
587 | int err; | |
51f7e52d | 588 | struct inode *inode; |
e9be9d5e MS |
589 | |
590 | err = ovl_want_write(old); | |
591 | if (err) | |
592 | goto out; | |
593 | ||
594 | err = ovl_copy_up(old); | |
595 | if (err) | |
596 | goto out_drop_write; | |
597 | ||
51f7e52d MS |
598 | inode = d_inode(old); |
599 | ihold(inode); | |
600 | ||
601 | err = ovl_create_or_link(new, inode, NULL, NULL, ovl_dentry_upper(old)); | |
602 | if (err) | |
603 | iput(inode); | |
e9be9d5e MS |
604 | |
605 | out_drop_write: | |
606 | ovl_drop_write(old); | |
607 | out: | |
608 | return err; | |
609 | } | |
610 | ||
a105d685 | 611 | static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir) |
e9be9d5e MS |
612 | { |
613 | struct dentry *workdir = ovl_workdir(dentry); | |
614 | struct inode *wdir = workdir->d_inode; | |
615 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
616 | struct inode *udir = upperdir->d_inode; | |
617 | struct dentry *whiteout; | |
618 | struct dentry *upper; | |
619 | struct dentry *opaquedir = NULL; | |
620 | int err; | |
cfc9fde0 | 621 | int flags = 0; |
e9be9d5e | 622 | |
cc6f67bc MS |
623 | if (WARN_ON(!workdir)) |
624 | return -EROFS; | |
625 | ||
d377c5eb | 626 | if (is_dir) { |
30c17ebf MS |
627 | opaquedir = ovl_check_empty_and_clear(dentry); |
628 | err = PTR_ERR(opaquedir); | |
629 | if (IS_ERR(opaquedir)) | |
630 | goto out; | |
e9be9d5e MS |
631 | } |
632 | ||
633 | err = ovl_lock_rename_workdir(workdir, upperdir); | |
634 | if (err) | |
635 | goto out_dput; | |
636 | ||
cfc9fde0 MP |
637 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
638 | dentry->d_name.len); | |
639 | err = PTR_ERR(upper); | |
640 | if (IS_ERR(upper)) | |
e9be9d5e MS |
641 | goto out_unlock; |
642 | ||
cfc9fde0 MP |
643 | err = -ESTALE; |
644 | if ((opaquedir && upper != opaquedir) || | |
645 | (!opaquedir && ovl_dentry_upper(dentry) && | |
646 | upper != ovl_dentry_upper(dentry))) { | |
647 | goto out_dput_upper; | |
648 | } | |
e9be9d5e | 649 | |
cfc9fde0 MP |
650 | whiteout = ovl_whiteout(workdir, dentry); |
651 | err = PTR_ERR(whiteout); | |
652 | if (IS_ERR(whiteout)) | |
653 | goto out_dput_upper; | |
e9be9d5e | 654 | |
cfc9fde0 MP |
655 | if (d_is_dir(upper)) |
656 | flags = RENAME_EXCHANGE; | |
e9be9d5e | 657 | |
cfc9fde0 MP |
658 | err = ovl_do_rename(wdir, whiteout, udir, upper, flags); |
659 | if (err) | |
660 | goto kill_whiteout; | |
661 | if (flags) | |
662 | ovl_cleanup(wdir, upper); | |
e9be9d5e | 663 | |
e9be9d5e MS |
664 | ovl_dentry_version_inc(dentry->d_parent); |
665 | out_d_drop: | |
666 | d_drop(dentry); | |
667 | dput(whiteout); | |
cfc9fde0 MP |
668 | out_dput_upper: |
669 | dput(upper); | |
e9be9d5e MS |
670 | out_unlock: |
671 | unlock_rename(workdir, upperdir); | |
672 | out_dput: | |
673 | dput(opaquedir); | |
674 | out: | |
675 | return err; | |
676 | ||
677 | kill_whiteout: | |
678 | ovl_cleanup(wdir, whiteout); | |
679 | goto out_d_drop; | |
680 | } | |
681 | ||
682 | static int ovl_remove_upper(struct dentry *dentry, bool is_dir) | |
683 | { | |
684 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
685 | struct inode *dir = upperdir->d_inode; | |
11f37104 | 686 | struct dentry *upper; |
e9be9d5e MS |
687 | int err; |
688 | ||
5955102c | 689 | inode_lock_nested(dir, I_MUTEX_PARENT); |
11f37104 MS |
690 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
691 | dentry->d_name.len); | |
692 | err = PTR_ERR(upper); | |
693 | if (IS_ERR(upper)) | |
694 | goto out_unlock; | |
695 | ||
e9be9d5e | 696 | err = -ESTALE; |
11f37104 | 697 | if (upper == ovl_dentry_upper(dentry)) { |
e9be9d5e MS |
698 | if (is_dir) |
699 | err = vfs_rmdir(dir, upper); | |
700 | else | |
701 | err = vfs_unlink(dir, upper, NULL); | |
e9be9d5e MS |
702 | ovl_dentry_version_inc(dentry->d_parent); |
703 | } | |
11f37104 | 704 | dput(upper); |
e9be9d5e MS |
705 | |
706 | /* | |
707 | * Keeping this dentry hashed would mean having to release | |
708 | * upperpath/lowerpath, which could only be done if we are the | |
709 | * sole user of this dentry. Too tricky... Just unhash for | |
710 | * now. | |
711 | */ | |
ce9113bb RW |
712 | if (!err) |
713 | d_drop(dentry); | |
11f37104 | 714 | out_unlock: |
5955102c | 715 | inode_unlock(dir); |
e9be9d5e MS |
716 | |
717 | return err; | |
718 | } | |
719 | ||
e9be9d5e MS |
720 | static int ovl_do_remove(struct dentry *dentry, bool is_dir) |
721 | { | |
722 | enum ovl_path_type type; | |
723 | int err; | |
1175b6b8 VG |
724 | const struct cred *old_cred; |
725 | ||
e9be9d5e MS |
726 | err = ovl_want_write(dentry); |
727 | if (err) | |
728 | goto out; | |
729 | ||
730 | err = ovl_copy_up(dentry->d_parent); | |
731 | if (err) | |
732 | goto out_drop_write; | |
733 | ||
734 | type = ovl_path_type(dentry); | |
e9be9d5e | 735 | |
1175b6b8 | 736 | old_cred = ovl_override_creds(dentry->d_sb); |
2aff4534 | 737 | if (!ovl_lower_positive(dentry)) |
1175b6b8 VG |
738 | err = ovl_remove_upper(dentry, is_dir); |
739 | else | |
a105d685 | 740 | err = ovl_remove_and_whiteout(dentry, is_dir); |
1175b6b8 | 741 | revert_creds(old_cred); |
dbc816d0 MS |
742 | if (!err) { |
743 | if (is_dir) | |
744 | clear_nlink(dentry->d_inode); | |
745 | else | |
746 | drop_nlink(dentry->d_inode); | |
747 | } | |
e9be9d5e MS |
748 | out_drop_write: |
749 | ovl_drop_write(dentry); | |
750 | out: | |
751 | return err; | |
752 | } | |
753 | ||
754 | static int ovl_unlink(struct inode *dir, struct dentry *dentry) | |
755 | { | |
756 | return ovl_do_remove(dentry, false); | |
757 | } | |
758 | ||
759 | static int ovl_rmdir(struct inode *dir, struct dentry *dentry) | |
760 | { | |
761 | return ovl_do_remove(dentry, true); | |
762 | } | |
763 | ||
370e55ac MS |
764 | static bool ovl_type_merge_or_lower(struct dentry *dentry) |
765 | { | |
766 | enum ovl_path_type type = ovl_path_type(dentry); | |
767 | ||
768 | return OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type); | |
769 | } | |
770 | ||
6c02cb59 MS |
771 | static int ovl_rename(struct inode *olddir, struct dentry *old, |
772 | struct inode *newdir, struct dentry *new, | |
773 | unsigned int flags) | |
e9be9d5e MS |
774 | { |
775 | int err; | |
e9be9d5e MS |
776 | struct dentry *old_upperdir; |
777 | struct dentry *new_upperdir; | |
778 | struct dentry *olddentry; | |
779 | struct dentry *newdentry; | |
780 | struct dentry *trap; | |
781 | bool old_opaque; | |
782 | bool new_opaque; | |
e9be9d5e MS |
783 | bool cleanup_whiteout = false; |
784 | bool overwrite = !(flags & RENAME_EXCHANGE); | |
e36cb0b8 | 785 | bool is_dir = d_is_dir(old); |
370e55ac | 786 | bool new_is_dir = d_is_dir(new); |
e9be9d5e MS |
787 | struct dentry *opaquedir = NULL; |
788 | const struct cred *old_cred = NULL; | |
e9be9d5e MS |
789 | |
790 | err = -EINVAL; | |
791 | if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) | |
792 | goto out; | |
793 | ||
794 | flags &= ~RENAME_NOREPLACE; | |
795 | ||
e9be9d5e | 796 | /* Don't copy up directory trees */ |
e9be9d5e | 797 | err = -EXDEV; |
370e55ac MS |
798 | if (is_dir && ovl_type_merge_or_lower(old)) |
799 | goto out; | |
800 | if (!overwrite && new_is_dir && ovl_type_merge_or_lower(new)) | |
e9be9d5e | 801 | goto out; |
e9be9d5e MS |
802 | |
803 | err = ovl_want_write(old); | |
804 | if (err) | |
805 | goto out; | |
806 | ||
807 | err = ovl_copy_up(old); | |
808 | if (err) | |
809 | goto out_drop_write; | |
810 | ||
811 | err = ovl_copy_up(new->d_parent); | |
812 | if (err) | |
813 | goto out_drop_write; | |
814 | if (!overwrite) { | |
815 | err = ovl_copy_up(new); | |
816 | if (err) | |
817 | goto out_drop_write; | |
818 | } | |
819 | ||
38e813db MS |
820 | old_opaque = ovl_dentry_is_opaque(old); |
821 | new_opaque = ovl_dentry_is_opaque(new); | |
e9be9d5e | 822 | |
1175b6b8 | 823 | old_cred = ovl_override_creds(old->d_sb); |
e9be9d5e | 824 | |
370e55ac | 825 | if (overwrite && new_is_dir && ovl_type_merge_or_lower(new)) { |
a105d685 | 826 | opaquedir = ovl_check_empty_and_clear(new); |
e9be9d5e MS |
827 | err = PTR_ERR(opaquedir); |
828 | if (IS_ERR(opaquedir)) { | |
829 | opaquedir = NULL; | |
830 | goto out_revert_creds; | |
831 | } | |
832 | } | |
833 | ||
834 | if (overwrite) { | |
2aff4534 | 835 | if (ovl_lower_positive(old)) { |
c412ce49 | 836 | if (!ovl_dentry_is_whiteout(new)) { |
e9be9d5e MS |
837 | /* Whiteout source */ |
838 | flags |= RENAME_WHITEOUT; | |
839 | } else { | |
840 | /* Switch whiteouts */ | |
841 | flags |= RENAME_EXCHANGE; | |
842 | } | |
c412ce49 | 843 | } else if (is_dir && ovl_dentry_is_whiteout(new)) { |
e9be9d5e MS |
844 | flags |= RENAME_EXCHANGE; |
845 | cleanup_whiteout = true; | |
846 | } | |
847 | } | |
848 | ||
849 | old_upperdir = ovl_dentry_upper(old->d_parent); | |
850 | new_upperdir = ovl_dentry_upper(new->d_parent); | |
851 | ||
852 | trap = lock_rename(new_upperdir, old_upperdir); | |
853 | ||
11f37104 MS |
854 | |
855 | olddentry = lookup_one_len(old->d_name.name, old_upperdir, | |
856 | old->d_name.len); | |
857 | err = PTR_ERR(olddentry); | |
858 | if (IS_ERR(olddentry)) | |
859 | goto out_unlock; | |
860 | ||
861 | err = -ESTALE; | |
862 | if (olddentry != ovl_dentry_upper(old)) | |
863 | goto out_dput_old; | |
864 | ||
865 | newdentry = lookup_one_len(new->d_name.name, new_upperdir, | |
866 | new->d_name.len); | |
867 | err = PTR_ERR(newdentry); | |
868 | if (IS_ERR(newdentry)) | |
869 | goto out_dput_old; | |
870 | ||
871 | err = -ESTALE; | |
872 | if (ovl_dentry_upper(new)) { | |
e9be9d5e | 873 | if (opaquedir) { |
11f37104 MS |
874 | if (newdentry != opaquedir) |
875 | goto out_dput; | |
e9be9d5e | 876 | } else { |
11f37104 MS |
877 | if (newdentry != ovl_dentry_upper(new)) |
878 | goto out_dput; | |
e9be9d5e MS |
879 | } |
880 | } else { | |
11f37104 MS |
881 | if (!d_is_negative(newdentry) && |
882 | (!new_opaque || !ovl_is_whiteout(newdentry))) | |
883 | goto out_dput; | |
e9be9d5e MS |
884 | } |
885 | ||
e9be9d5e MS |
886 | if (olddentry == trap) |
887 | goto out_dput; | |
888 | if (newdentry == trap) | |
889 | goto out_dput; | |
890 | ||
804032fa MS |
891 | if (WARN_ON(olddentry->d_inode == newdentry->d_inode)) |
892 | goto out_dput; | |
893 | ||
e9be9d5e MS |
894 | if (is_dir && !old_opaque && new_opaque) { |
895 | err = ovl_set_opaque(olddentry); | |
896 | if (err) | |
897 | goto out_dput; | |
898 | } | |
899 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) { | |
900 | err = ovl_set_opaque(newdentry); | |
901 | if (err) | |
902 | goto out_dput; | |
903 | } | |
904 | ||
905 | if (old_opaque || new_opaque) { | |
906 | err = ovl_do_rename(old_upperdir->d_inode, olddentry, | |
907 | new_upperdir->d_inode, newdentry, | |
908 | flags); | |
909 | } else { | |
910 | /* No debug for the plain case */ | |
911 | BUG_ON(flags & ~RENAME_EXCHANGE); | |
912 | err = vfs_rename(old_upperdir->d_inode, olddentry, | |
913 | new_upperdir->d_inode, newdentry, | |
914 | NULL, flags); | |
915 | } | |
916 | ||
917 | if (err) { | |
918 | if (is_dir && !old_opaque && new_opaque) | |
919 | ovl_remove_opaque(olddentry); | |
920 | if (!overwrite && new_is_dir && old_opaque && !new_opaque) | |
921 | ovl_remove_opaque(newdentry); | |
922 | goto out_dput; | |
923 | } | |
924 | ||
925 | if (is_dir && old_opaque && !new_opaque) | |
926 | ovl_remove_opaque(olddentry); | |
927 | if (!overwrite && new_is_dir && !old_opaque && new_opaque) | |
928 | ovl_remove_opaque(newdentry); | |
929 | ||
45d11738 KK |
930 | /* |
931 | * Old dentry now lives in different location. Dentries in | |
932 | * lowerstack are stale. We cannot drop them here because | |
933 | * access to them is lockless. This could be only pure upper | |
934 | * or opaque directory - numlower is zero. Or upper non-dir | |
935 | * entry - its pureness is tracked by flag opaque. | |
936 | */ | |
e9be9d5e MS |
937 | if (old_opaque != new_opaque) { |
938 | ovl_dentry_set_opaque(old, new_opaque); | |
939 | if (!overwrite) | |
940 | ovl_dentry_set_opaque(new, old_opaque); | |
941 | } | |
942 | ||
943 | if (cleanup_whiteout) | |
944 | ovl_cleanup(old_upperdir->d_inode, newdentry); | |
945 | ||
946 | ovl_dentry_version_inc(old->d_parent); | |
947 | ovl_dentry_version_inc(new->d_parent); | |
948 | ||
949 | out_dput: | |
950 | dput(newdentry); | |
11f37104 MS |
951 | out_dput_old: |
952 | dput(olddentry); | |
e9be9d5e MS |
953 | out_unlock: |
954 | unlock_rename(new_upperdir, old_upperdir); | |
955 | out_revert_creds: | |
1175b6b8 | 956 | revert_creds(old_cred); |
e9be9d5e MS |
957 | out_drop_write: |
958 | ovl_drop_write(old); | |
959 | out: | |
960 | dput(opaquedir); | |
961 | return err; | |
962 | } | |
963 | ||
964 | const struct inode_operations ovl_dir_inode_operations = { | |
965 | .lookup = ovl_lookup, | |
966 | .mkdir = ovl_mkdir, | |
967 | .symlink = ovl_symlink, | |
968 | .unlink = ovl_unlink, | |
969 | .rmdir = ovl_rmdir, | |
6c02cb59 | 970 | .rename = ovl_rename, |
e9be9d5e MS |
971 | .link = ovl_link, |
972 | .setattr = ovl_setattr, | |
973 | .create = ovl_create, | |
974 | .mknod = ovl_mknod, | |
975 | .permission = ovl_permission, | |
976 | .getattr = ovl_dir_getattr, | |
e9be9d5e | 977 | .listxattr = ovl_listxattr, |
39a25b2b | 978 | .get_acl = ovl_get_acl, |
d719e8f2 | 979 | .update_time = ovl_update_time, |
e9be9d5e | 980 | }; |