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Commit | Line | Data |
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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> | |
3ea22a71 | 15 | #include <linux/module.h> |
38b25697 MS |
16 | #include <linux/posix_acl.h> |
17 | #include <linux/posix_acl_xattr.h> | |
6a45b362 | 18 | #include <linux/atomic.h> |
a6c60655 | 19 | #include <linux/ratelimit.h> |
e9be9d5e MS |
20 | #include "overlayfs.h" |
21 | ||
3ea22a71 MS |
22 | static unsigned short ovl_redirect_max = 256; |
23 | module_param_named(redirect_max, ovl_redirect_max, ushort, 0644); | |
24 | MODULE_PARM_DESC(ovl_redirect_max, | |
25 | "Maximum length of absolute redirect xattr value"); | |
26 | ||
e9be9d5e MS |
27 | void ovl_cleanup(struct inode *wdir, struct dentry *wdentry) |
28 | { | |
29 | int err; | |
30 | ||
31 | dget(wdentry); | |
e36cb0b8 | 32 | if (d_is_dir(wdentry)) |
e9be9d5e MS |
33 | err = ovl_do_rmdir(wdir, wdentry); |
34 | else | |
35 | err = ovl_do_unlink(wdir, wdentry); | |
36 | dput(wdentry); | |
37 | ||
38 | if (err) { | |
39 | pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n", | |
40 | wdentry, err); | |
41 | } | |
42 | } | |
43 | ||
3d27573c | 44 | struct dentry *ovl_lookup_temp(struct dentry *workdir) |
e9be9d5e MS |
45 | { |
46 | struct dentry *temp; | |
47 | char name[20]; | |
6a45b362 | 48 | static atomic_t temp_id = ATOMIC_INIT(0); |
e9be9d5e | 49 | |
6a45b362 RW |
50 | /* counter is allowed to wrap, since temp dentries are ephemeral */ |
51 | snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id)); | |
e9be9d5e MS |
52 | |
53 | temp = lookup_one_len(name, workdir, strlen(name)); | |
54 | if (!IS_ERR(temp) && temp->d_inode) { | |
55 | pr_err("overlayfs: workdir/%s already exists\n", name); | |
56 | dput(temp); | |
57 | temp = ERR_PTR(-EIO); | |
58 | } | |
59 | ||
60 | return temp; | |
61 | } | |
62 | ||
63 | /* caller holds i_mutex on workdir */ | |
64 | static struct dentry *ovl_whiteout(struct dentry *workdir, | |
65 | struct dentry *dentry) | |
66 | { | |
67 | int err; | |
68 | struct dentry *whiteout; | |
69 | struct inode *wdir = workdir->d_inode; | |
70 | ||
3d27573c | 71 | whiteout = ovl_lookup_temp(workdir); |
e9be9d5e MS |
72 | if (IS_ERR(whiteout)) |
73 | return whiteout; | |
74 | ||
75 | err = ovl_do_whiteout(wdir, whiteout); | |
76 | if (err) { | |
77 | dput(whiteout); | |
78 | whiteout = ERR_PTR(err); | |
79 | } | |
80 | ||
81 | return whiteout; | |
82 | } | |
83 | ||
84 | int ovl_create_real(struct inode *dir, struct dentry *newdentry, | |
32a3d848 | 85 | struct cattr *attr, struct dentry *hardlink, bool debug) |
e9be9d5e MS |
86 | { |
87 | int err; | |
88 | ||
89 | if (newdentry->d_inode) | |
90 | return -ESTALE; | |
91 | ||
92 | if (hardlink) { | |
93 | err = ovl_do_link(hardlink, dir, newdentry, debug); | |
94 | } else { | |
32a3d848 | 95 | switch (attr->mode & S_IFMT) { |
e9be9d5e | 96 | case S_IFREG: |
32a3d848 | 97 | err = ovl_do_create(dir, newdentry, attr->mode, debug); |
e9be9d5e MS |
98 | break; |
99 | ||
100 | case S_IFDIR: | |
32a3d848 | 101 | err = ovl_do_mkdir(dir, newdentry, attr->mode, debug); |
e9be9d5e MS |
102 | break; |
103 | ||
104 | case S_IFCHR: | |
105 | case S_IFBLK: | |
106 | case S_IFIFO: | |
107 | case S_IFSOCK: | |
108 | err = ovl_do_mknod(dir, newdentry, | |
32a3d848 | 109 | attr->mode, attr->rdev, debug); |
e9be9d5e MS |
110 | break; |
111 | ||
112 | case S_IFLNK: | |
32a3d848 | 113 | err = ovl_do_symlink(dir, newdentry, attr->link, debug); |
e9be9d5e MS |
114 | break; |
115 | ||
116 | default: | |
117 | err = -EPERM; | |
118 | } | |
119 | } | |
120 | if (!err && WARN_ON(!newdentry->d_inode)) { | |
121 | /* | |
122 | * Not quite sure if non-instantiated dentry is legal or not. | |
123 | * VFS doesn't seem to care so check and warn here. | |
124 | */ | |
125 | err = -ENOENT; | |
126 | } | |
127 | return err; | |
128 | } | |
129 | ||
21a22878 AG |
130 | static int ovl_set_opaque_xerr(struct dentry *dentry, struct dentry *upper, |
131 | int xerr) | |
e9be9d5e | 132 | { |
5cf5b477 MS |
133 | int err; |
134 | ||
21a22878 | 135 | err = ovl_check_setxattr(dentry, upper, OVL_XATTR_OPAQUE, "y", 1, xerr); |
5cf5b477 MS |
136 | if (!err) |
137 | ovl_dentry_set_opaque(dentry); | |
138 | ||
139 | return err; | |
e9be9d5e MS |
140 | } |
141 | ||
21a22878 AG |
142 | static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry) |
143 | { | |
144 | /* | |
145 | * Fail with -EIO when trying to create opaque dir and upper doesn't | |
146 | * support xattrs. ovl_rename() calls ovl_set_opaque_xerr(-EXDEV) to | |
147 | * return a specific error for noxattr case. | |
148 | */ | |
149 | return ovl_set_opaque_xerr(dentry, upperdentry, -EIO); | |
150 | } | |
151 | ||
72e48481 VG |
152 | /* Common operations required to be done after creation of file on upper */ |
153 | static void ovl_instantiate(struct dentry *dentry, struct inode *inode, | |
51f7e52d | 154 | struct dentry *newdentry, bool hardlink) |
72e48481 VG |
155 | { |
156 | ovl_dentry_version_inc(dentry->d_parent); | |
157 | ovl_dentry_update(dentry, newdentry); | |
51f7e52d MS |
158 | if (!hardlink) { |
159 | ovl_inode_update(inode, d_inode(newdentry)); | |
160 | ovl_copyattr(newdentry->d_inode, inode); | |
161 | } else { | |
162 | WARN_ON(ovl_inode_real(inode, NULL) != d_inode(newdentry)); | |
163 | inc_nlink(inode); | |
164 | } | |
72e48481 | 165 | d_instantiate(dentry, inode); |
5b6c9053 AG |
166 | /* Force lookup of new upper hardlink to find its lower */ |
167 | if (hardlink) | |
168 | d_drop(dentry); | |
72e48481 VG |
169 | } |
170 | ||
97c684cc AG |
171 | static bool ovl_type_merge(struct dentry *dentry) |
172 | { | |
173 | return OVL_TYPE_MERGE(ovl_path_type(dentry)); | |
174 | } | |
175 | ||
e9be9d5e | 176 | static int ovl_create_upper(struct dentry *dentry, struct inode *inode, |
32a3d848 | 177 | struct cattr *attr, struct dentry *hardlink) |
e9be9d5e MS |
178 | { |
179 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
180 | struct inode *udir = upperdir->d_inode; | |
181 | struct dentry *newdentry; | |
182 | int err; | |
183 | ||
38b25697 | 184 | if (!hardlink && !IS_POSIXACL(udir)) |
32a3d848 | 185 | attr->mode &= ~current_umask(); |
38b25697 | 186 | |
5955102c | 187 | inode_lock_nested(udir, I_MUTEX_PARENT); |
e9be9d5e MS |
188 | newdentry = lookup_one_len(dentry->d_name.name, upperdir, |
189 | dentry->d_name.len); | |
190 | err = PTR_ERR(newdentry); | |
191 | if (IS_ERR(newdentry)) | |
192 | goto out_unlock; | |
32a3d848 | 193 | err = ovl_create_real(udir, newdentry, attr, hardlink, false); |
e9be9d5e MS |
194 | if (err) |
195 | goto out_dput; | |
196 | ||
4a99f3c8 | 197 | if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry)) { |
97c684cc AG |
198 | /* Setting opaque here is just an optimization, allow to fail */ |
199 | ovl_set_opaque(dentry, newdentry); | |
200 | } | |
201 | ||
51f7e52d | 202 | ovl_instantiate(dentry, inode, newdentry, !!hardlink); |
e9be9d5e MS |
203 | newdentry = NULL; |
204 | out_dput: | |
205 | dput(newdentry); | |
206 | out_unlock: | |
5955102c | 207 | inode_unlock(udir); |
e9be9d5e MS |
208 | return err; |
209 | } | |
210 | ||
211 | static int ovl_lock_rename_workdir(struct dentry *workdir, | |
212 | struct dentry *upperdir) | |
213 | { | |
214 | /* Workdir should not be the same as upperdir */ | |
215 | if (workdir == upperdir) | |
216 | goto err; | |
217 | ||
218 | /* Workdir should not be subdir of upperdir and vice versa */ | |
219 | if (lock_rename(workdir, upperdir) != NULL) | |
220 | goto err_unlock; | |
221 | ||
222 | return 0; | |
223 | ||
224 | err_unlock: | |
225 | unlock_rename(workdir, upperdir); | |
226 | err: | |
227 | pr_err("overlayfs: failed to lock workdir+upperdir\n"); | |
228 | return -EIO; | |
229 | } | |
230 | ||
231 | static struct dentry *ovl_clear_empty(struct dentry *dentry, | |
232 | struct list_head *list) | |
233 | { | |
234 | struct dentry *workdir = ovl_workdir(dentry); | |
235 | struct inode *wdir = workdir->d_inode; | |
236 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
237 | struct inode *udir = upperdir->d_inode; | |
238 | struct path upperpath; | |
239 | struct dentry *upper; | |
240 | struct dentry *opaquedir; | |
241 | struct kstat stat; | |
242 | int err; | |
243 | ||
cc6f67bc MS |
244 | if (WARN_ON(!workdir)) |
245 | return ERR_PTR(-EROFS); | |
246 | ||
e9be9d5e MS |
247 | err = ovl_lock_rename_workdir(workdir, upperdir); |
248 | if (err) | |
249 | goto out; | |
250 | ||
251 | ovl_path_upper(dentry, &upperpath); | |
a528d35e DH |
252 | err = vfs_getattr(&upperpath, &stat, |
253 | STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT); | |
e9be9d5e MS |
254 | if (err) |
255 | goto out_unlock; | |
256 | ||
257 | err = -ESTALE; | |
258 | if (!S_ISDIR(stat.mode)) | |
259 | goto out_unlock; | |
260 | upper = upperpath.dentry; | |
261 | if (upper->d_parent->d_inode != udir) | |
262 | goto out_unlock; | |
263 | ||
3d27573c | 264 | opaquedir = ovl_lookup_temp(workdir); |
e9be9d5e MS |
265 | err = PTR_ERR(opaquedir); |
266 | if (IS_ERR(opaquedir)) | |
267 | goto out_unlock; | |
268 | ||
32a3d848 AV |
269 | err = ovl_create_real(wdir, opaquedir, |
270 | &(struct cattr){.mode = stat.mode}, NULL, true); | |
e9be9d5e MS |
271 | if (err) |
272 | goto out_dput; | |
273 | ||
274 | err = ovl_copy_xattr(upper, opaquedir); | |
275 | if (err) | |
276 | goto out_cleanup; | |
277 | ||
5cf5b477 | 278 | err = ovl_set_opaque(dentry, opaquedir); |
e9be9d5e MS |
279 | if (err) |
280 | goto out_cleanup; | |
281 | ||
5955102c | 282 | inode_lock(opaquedir->d_inode); |
e9be9d5e | 283 | err = ovl_set_attr(opaquedir, &stat); |
5955102c | 284 | inode_unlock(opaquedir->d_inode); |
e9be9d5e MS |
285 | if (err) |
286 | goto out_cleanup; | |
287 | ||
288 | err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE); | |
289 | if (err) | |
290 | goto out_cleanup; | |
291 | ||
292 | ovl_cleanup_whiteouts(upper, list); | |
293 | ovl_cleanup(wdir, upper); | |
294 | unlock_rename(workdir, upperdir); | |
295 | ||
296 | /* dentry's upper doesn't match now, get rid of it */ | |
297 | d_drop(dentry); | |
298 | ||
299 | return opaquedir; | |
300 | ||
301 | out_cleanup: | |
302 | ovl_cleanup(wdir, opaquedir); | |
303 | out_dput: | |
304 | dput(opaquedir); | |
305 | out_unlock: | |
306 | unlock_rename(workdir, upperdir); | |
307 | out: | |
308 | return ERR_PTR(err); | |
309 | } | |
310 | ||
a105d685 | 311 | static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry) |
e9be9d5e MS |
312 | { |
313 | int err; | |
314 | struct dentry *ret = NULL; | |
30c17ebf | 315 | enum ovl_path_type type = ovl_path_type(dentry); |
e9be9d5e MS |
316 | LIST_HEAD(list); |
317 | ||
318 | err = ovl_check_empty_dir(dentry, &list); | |
30c17ebf | 319 | if (err) { |
e9be9d5e | 320 | ret = ERR_PTR(err); |
30c17ebf | 321 | goto out_free; |
a105d685 | 322 | } |
e9be9d5e | 323 | |
30c17ebf MS |
324 | /* |
325 | * When removing an empty opaque directory, then it makes no sense to | |
326 | * replace it with an exact replica of itself. | |
327 | * | |
328 | * If no upperdentry then skip clearing whiteouts. | |
329 | * | |
330 | * Can race with copy-up, since we don't hold the upperdir mutex. | |
331 | * Doesn't matter, since copy-up can't create a non-empty directory | |
332 | * from an empty one. | |
333 | */ | |
334 | if (OVL_TYPE_UPPER(type) && OVL_TYPE_MERGE(type)) | |
335 | ret = ovl_clear_empty(dentry, &list); | |
336 | ||
337 | out_free: | |
e9be9d5e MS |
338 | ovl_cache_free(&list); |
339 | ||
340 | return ret; | |
341 | } | |
342 | ||
38b25697 MS |
343 | static int ovl_set_upper_acl(struct dentry *upperdentry, const char *name, |
344 | const struct posix_acl *acl) | |
345 | { | |
346 | void *buffer; | |
347 | size_t size; | |
348 | int err; | |
349 | ||
350 | if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl) | |
351 | return 0; | |
352 | ||
353 | size = posix_acl_to_xattr(NULL, acl, NULL, 0); | |
354 | buffer = kmalloc(size, GFP_KERNEL); | |
355 | if (!buffer) | |
356 | return -ENOMEM; | |
357 | ||
358 | size = posix_acl_to_xattr(&init_user_ns, acl, buffer, size); | |
359 | err = size; | |
360 | if (err < 0) | |
361 | goto out_free; | |
362 | ||
363 | err = vfs_setxattr(upperdentry, name, buffer, size, XATTR_CREATE); | |
364 | out_free: | |
365 | kfree(buffer); | |
366 | return err; | |
367 | } | |
368 | ||
e9be9d5e | 369 | static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, |
32a3d848 | 370 | struct cattr *cattr, |
e9be9d5e MS |
371 | struct dentry *hardlink) |
372 | { | |
373 | struct dentry *workdir = ovl_workdir(dentry); | |
374 | struct inode *wdir = workdir->d_inode; | |
375 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
376 | struct inode *udir = upperdir->d_inode; | |
377 | struct dentry *upper; | |
378 | struct dentry *newdentry; | |
379 | int err; | |
38b25697 | 380 | struct posix_acl *acl, *default_acl; |
e9be9d5e | 381 | |
cc6f67bc MS |
382 | if (WARN_ON(!workdir)) |
383 | return -EROFS; | |
384 | ||
38b25697 MS |
385 | if (!hardlink) { |
386 | err = posix_acl_create(dentry->d_parent->d_inode, | |
32a3d848 | 387 | &cattr->mode, &default_acl, &acl); |
38b25697 MS |
388 | if (err) |
389 | return err; | |
390 | } | |
391 | ||
e9be9d5e MS |
392 | err = ovl_lock_rename_workdir(workdir, upperdir); |
393 | if (err) | |
394 | goto out; | |
395 | ||
3d27573c | 396 | newdentry = ovl_lookup_temp(workdir); |
e9be9d5e MS |
397 | err = PTR_ERR(newdentry); |
398 | if (IS_ERR(newdentry)) | |
399 | goto out_unlock; | |
400 | ||
401 | upper = lookup_one_len(dentry->d_name.name, upperdir, | |
402 | dentry->d_name.len); | |
403 | err = PTR_ERR(upper); | |
404 | if (IS_ERR(upper)) | |
405 | goto out_dput; | |
406 | ||
32a3d848 | 407 | err = ovl_create_real(wdir, newdentry, cattr, hardlink, true); |
e9be9d5e MS |
408 | if (err) |
409 | goto out_dput2; | |
410 | ||
bb0d2b8a MS |
411 | /* |
412 | * mode could have been mutilated due to umask (e.g. sgid directory) | |
413 | */ | |
51f7e52d | 414 | if (!hardlink && |
32a3d848 AV |
415 | !S_ISLNK(cattr->mode) && |
416 | newdentry->d_inode->i_mode != cattr->mode) { | |
bb0d2b8a MS |
417 | struct iattr attr = { |
418 | .ia_valid = ATTR_MODE, | |
32a3d848 | 419 | .ia_mode = cattr->mode, |
bb0d2b8a MS |
420 | }; |
421 | inode_lock(newdentry->d_inode); | |
422 | err = notify_change(newdentry, &attr, NULL); | |
423 | inode_unlock(newdentry->d_inode); | |
424 | if (err) | |
425 | goto out_cleanup; | |
426 | } | |
38b25697 MS |
427 | if (!hardlink) { |
428 | err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS, | |
429 | acl); | |
430 | if (err) | |
431 | goto out_cleanup; | |
432 | ||
433 | err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT, | |
434 | default_acl); | |
435 | if (err) | |
436 | goto out_cleanup; | |
437 | } | |
bb0d2b8a | 438 | |
32a3d848 | 439 | if (!hardlink && S_ISDIR(cattr->mode)) { |
5cf5b477 | 440 | err = ovl_set_opaque(dentry, newdentry); |
e9be9d5e MS |
441 | if (err) |
442 | goto out_cleanup; | |
443 | ||
444 | err = ovl_do_rename(wdir, newdentry, udir, upper, | |
445 | RENAME_EXCHANGE); | |
446 | if (err) | |
447 | goto out_cleanup; | |
448 | ||
449 | ovl_cleanup(wdir, upper); | |
450 | } else { | |
451 | err = ovl_do_rename(wdir, newdentry, udir, upper, 0); | |
452 | if (err) | |
453 | goto out_cleanup; | |
454 | } | |
51f7e52d | 455 | ovl_instantiate(dentry, inode, newdentry, !!hardlink); |
e9be9d5e MS |
456 | newdentry = NULL; |
457 | out_dput2: | |
458 | dput(upper); | |
459 | out_dput: | |
460 | dput(newdentry); | |
461 | out_unlock: | |
462 | unlock_rename(workdir, upperdir); | |
463 | out: | |
38b25697 MS |
464 | if (!hardlink) { |
465 | posix_acl_release(acl); | |
466 | posix_acl_release(default_acl); | |
467 | } | |
e9be9d5e MS |
468 | return err; |
469 | ||
470 | out_cleanup: | |
471 | ovl_cleanup(wdir, newdentry); | |
472 | goto out_dput2; | |
473 | } | |
474 | ||
51f7e52d | 475 | static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, |
32a3d848 | 476 | struct cattr *attr, struct dentry *hardlink) |
e9be9d5e MS |
477 | { |
478 | int err; | |
1175b6b8 VG |
479 | const struct cred *old_cred; |
480 | struct cred *override_cred; | |
e9be9d5e MS |
481 | |
482 | err = ovl_copy_up(dentry->d_parent); | |
483 | if (err) | |
51f7e52d | 484 | return err; |
bb0d2b8a | 485 | |
1175b6b8 VG |
486 | old_cred = ovl_override_creds(dentry->d_sb); |
487 | err = -ENOMEM; | |
488 | override_cred = prepare_creds(); | |
489 | if (override_cred) { | |
bb0d2b8a MS |
490 | override_cred->fsuid = inode->i_uid; |
491 | override_cred->fsgid = inode->i_gid; | |
2602625b VG |
492 | if (!hardlink) { |
493 | err = security_dentry_create_files_as(dentry, | |
32a3d848 | 494 | attr->mode, &dentry->d_name, old_cred, |
2602625b VG |
495 | override_cred); |
496 | if (err) { | |
497 | put_cred(override_cred); | |
498 | goto out_revert_creds; | |
499 | } | |
500 | } | |
1175b6b8 VG |
501 | put_cred(override_creds(override_cred)); |
502 | put_cred(override_cred); | |
503 | ||
c412ce49 | 504 | if (!ovl_dentry_is_whiteout(dentry)) |
32a3d848 | 505 | err = ovl_create_upper(dentry, inode, attr, |
1175b6b8 VG |
506 | hardlink); |
507 | else | |
32a3d848 AV |
508 | err = ovl_create_over_whiteout(dentry, inode, attr, |
509 | hardlink); | |
e9be9d5e | 510 | } |
2602625b | 511 | out_revert_creds: |
1175b6b8 | 512 | revert_creds(old_cred); |
bb0d2b8a MS |
513 | if (!err) { |
514 | struct inode *realinode = d_inode(ovl_dentry_upper(dentry)); | |
515 | ||
516 | WARN_ON(inode->i_mode != realinode->i_mode); | |
517 | WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid)); | |
518 | WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid)); | |
bb0d2b8a | 519 | } |
e9be9d5e MS |
520 | return err; |
521 | } | |
522 | ||
523 | static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, | |
524 | const char *link) | |
525 | { | |
526 | int err; | |
51f7e52d | 527 | struct inode *inode; |
32a3d848 | 528 | struct cattr attr = { |
51f7e52d | 529 | .rdev = rdev, |
32a3d848 | 530 | .link = link, |
51f7e52d | 531 | }; |
e9be9d5e MS |
532 | |
533 | err = ovl_want_write(dentry); | |
51f7e52d MS |
534 | if (err) |
535 | goto out; | |
536 | ||
537 | err = -ENOMEM; | |
ca4c8a3a | 538 | inode = ovl_new_inode(dentry->d_sb, mode, rdev); |
51f7e52d MS |
539 | if (!inode) |
540 | goto out_drop_write; | |
541 | ||
542 | inode_init_owner(inode, dentry->d_parent->d_inode, mode); | |
32a3d848 | 543 | attr.mode = inode->i_mode; |
51f7e52d | 544 | |
32a3d848 | 545 | err = ovl_create_or_link(dentry, inode, &attr, NULL); |
51f7e52d MS |
546 | if (err) |
547 | iput(inode); | |
e9be9d5e | 548 | |
51f7e52d MS |
549 | out_drop_write: |
550 | ovl_drop_write(dentry); | |
551 | out: | |
e9be9d5e MS |
552 | return err; |
553 | } | |
554 | ||
555 | static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode, | |
556 | bool excl) | |
557 | { | |
558 | return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL); | |
559 | } | |
560 | ||
561 | static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) | |
562 | { | |
563 | return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL); | |
564 | } | |
565 | ||
566 | static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, | |
567 | dev_t rdev) | |
568 | { | |
569 | /* Don't allow creation of "whiteout" on overlay */ | |
570 | if (S_ISCHR(mode) && rdev == WHITEOUT_DEV) | |
571 | return -EPERM; | |
572 | ||
573 | return ovl_create_object(dentry, mode, rdev, NULL); | |
574 | } | |
575 | ||
576 | static int ovl_symlink(struct inode *dir, struct dentry *dentry, | |
577 | const char *link) | |
578 | { | |
579 | return ovl_create_object(dentry, S_IFLNK, 0, link); | |
580 | } | |
581 | ||
582 | static int ovl_link(struct dentry *old, struct inode *newdir, | |
583 | struct dentry *new) | |
584 | { | |
585 | int err; | |
51f7e52d | 586 | struct inode *inode; |
e9be9d5e MS |
587 | |
588 | err = ovl_want_write(old); | |
589 | if (err) | |
590 | goto out; | |
591 | ||
592 | err = ovl_copy_up(old); | |
593 | if (err) | |
594 | goto out_drop_write; | |
595 | ||
51f7e52d MS |
596 | inode = d_inode(old); |
597 | ihold(inode); | |
598 | ||
32a3d848 | 599 | err = ovl_create_or_link(new, inode, NULL, ovl_dentry_upper(old)); |
51f7e52d MS |
600 | if (err) |
601 | iput(inode); | |
e9be9d5e MS |
602 | |
603 | out_drop_write: | |
604 | ovl_drop_write(old); | |
605 | out: | |
606 | return err; | |
607 | } | |
608 | ||
a105d685 | 609 | static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir) |
e9be9d5e MS |
610 | { |
611 | struct dentry *workdir = ovl_workdir(dentry); | |
612 | struct inode *wdir = workdir->d_inode; | |
613 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
614 | struct inode *udir = upperdir->d_inode; | |
615 | struct dentry *whiteout; | |
616 | struct dentry *upper; | |
617 | struct dentry *opaquedir = NULL; | |
618 | int err; | |
cfc9fde0 | 619 | int flags = 0; |
e9be9d5e | 620 | |
cc6f67bc MS |
621 | if (WARN_ON(!workdir)) |
622 | return -EROFS; | |
623 | ||
d377c5eb | 624 | if (is_dir) { |
30c17ebf MS |
625 | opaquedir = ovl_check_empty_and_clear(dentry); |
626 | err = PTR_ERR(opaquedir); | |
627 | if (IS_ERR(opaquedir)) | |
628 | goto out; | |
e9be9d5e MS |
629 | } |
630 | ||
631 | err = ovl_lock_rename_workdir(workdir, upperdir); | |
632 | if (err) | |
633 | goto out_dput; | |
634 | ||
cfc9fde0 MP |
635 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
636 | dentry->d_name.len); | |
637 | err = PTR_ERR(upper); | |
638 | if (IS_ERR(upper)) | |
e9be9d5e MS |
639 | goto out_unlock; |
640 | ||
cfc9fde0 MP |
641 | err = -ESTALE; |
642 | if ((opaquedir && upper != opaquedir) || | |
643 | (!opaquedir && ovl_dentry_upper(dentry) && | |
644 | upper != ovl_dentry_upper(dentry))) { | |
645 | goto out_dput_upper; | |
646 | } | |
e9be9d5e | 647 | |
cfc9fde0 MP |
648 | whiteout = ovl_whiteout(workdir, dentry); |
649 | err = PTR_ERR(whiteout); | |
650 | if (IS_ERR(whiteout)) | |
651 | goto out_dput_upper; | |
e9be9d5e | 652 | |
cfc9fde0 MP |
653 | if (d_is_dir(upper)) |
654 | flags = RENAME_EXCHANGE; | |
e9be9d5e | 655 | |
cfc9fde0 MP |
656 | err = ovl_do_rename(wdir, whiteout, udir, upper, flags); |
657 | if (err) | |
658 | goto kill_whiteout; | |
659 | if (flags) | |
660 | ovl_cleanup(wdir, upper); | |
e9be9d5e | 661 | |
e9be9d5e MS |
662 | ovl_dentry_version_inc(dentry->d_parent); |
663 | out_d_drop: | |
664 | d_drop(dentry); | |
665 | dput(whiteout); | |
cfc9fde0 MP |
666 | out_dput_upper: |
667 | dput(upper); | |
e9be9d5e MS |
668 | out_unlock: |
669 | unlock_rename(workdir, upperdir); | |
670 | out_dput: | |
671 | dput(opaquedir); | |
672 | out: | |
673 | return err; | |
674 | ||
675 | kill_whiteout: | |
676 | ovl_cleanup(wdir, whiteout); | |
677 | goto out_d_drop; | |
678 | } | |
679 | ||
680 | static int ovl_remove_upper(struct dentry *dentry, bool is_dir) | |
681 | { | |
682 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
683 | struct inode *dir = upperdir->d_inode; | |
11f37104 | 684 | struct dentry *upper; |
d1595119 | 685 | struct dentry *opaquedir = NULL; |
e9be9d5e MS |
686 | int err; |
687 | ||
d1595119 AG |
688 | /* Redirect dir can be !ovl_lower_positive && OVL_TYPE_MERGE */ |
689 | if (is_dir && ovl_dentry_get_redirect(dentry)) { | |
690 | opaquedir = ovl_check_empty_and_clear(dentry); | |
691 | err = PTR_ERR(opaquedir); | |
692 | if (IS_ERR(opaquedir)) | |
693 | goto out; | |
694 | } | |
695 | ||
5955102c | 696 | inode_lock_nested(dir, I_MUTEX_PARENT); |
11f37104 MS |
697 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
698 | dentry->d_name.len); | |
699 | err = PTR_ERR(upper); | |
700 | if (IS_ERR(upper)) | |
701 | goto out_unlock; | |
702 | ||
e9be9d5e | 703 | err = -ESTALE; |
d1595119 AG |
704 | if ((opaquedir && upper != opaquedir) || |
705 | (!opaquedir && upper != ovl_dentry_upper(dentry))) | |
706 | goto out_dput_upper; | |
707 | ||
708 | if (is_dir) | |
709 | err = vfs_rmdir(dir, upper); | |
710 | else | |
711 | err = vfs_unlink(dir, upper, NULL); | |
712 | ovl_dentry_version_inc(dentry->d_parent); | |
e9be9d5e MS |
713 | |
714 | /* | |
715 | * Keeping this dentry hashed would mean having to release | |
716 | * upperpath/lowerpath, which could only be done if we are the | |
717 | * sole user of this dentry. Too tricky... Just unhash for | |
718 | * now. | |
719 | */ | |
ce9113bb RW |
720 | if (!err) |
721 | d_drop(dentry); | |
d1595119 AG |
722 | out_dput_upper: |
723 | dput(upper); | |
11f37104 | 724 | out_unlock: |
5955102c | 725 | inode_unlock(dir); |
d1595119 AG |
726 | dput(opaquedir); |
727 | out: | |
e9be9d5e MS |
728 | return err; |
729 | } | |
730 | ||
e9be9d5e MS |
731 | static int ovl_do_remove(struct dentry *dentry, bool is_dir) |
732 | { | |
733 | enum ovl_path_type type; | |
734 | int err; | |
1175b6b8 VG |
735 | const struct cred *old_cred; |
736 | ||
e9be9d5e MS |
737 | err = ovl_want_write(dentry); |
738 | if (err) | |
739 | goto out; | |
740 | ||
741 | err = ovl_copy_up(dentry->d_parent); | |
742 | if (err) | |
743 | goto out_drop_write; | |
744 | ||
745 | type = ovl_path_type(dentry); | |
e9be9d5e | 746 | |
1175b6b8 | 747 | old_cred = ovl_override_creds(dentry->d_sb); |
2aff4534 | 748 | if (!ovl_lower_positive(dentry)) |
1175b6b8 VG |
749 | err = ovl_remove_upper(dentry, is_dir); |
750 | else | |
a105d685 | 751 | err = ovl_remove_and_whiteout(dentry, is_dir); |
1175b6b8 | 752 | revert_creds(old_cred); |
dbc816d0 MS |
753 | if (!err) { |
754 | if (is_dir) | |
755 | clear_nlink(dentry->d_inode); | |
756 | else | |
757 | drop_nlink(dentry->d_inode); | |
758 | } | |
e9be9d5e MS |
759 | out_drop_write: |
760 | ovl_drop_write(dentry); | |
761 | out: | |
762 | return err; | |
763 | } | |
764 | ||
765 | static int ovl_unlink(struct inode *dir, struct dentry *dentry) | |
766 | { | |
767 | return ovl_do_remove(dentry, false); | |
768 | } | |
769 | ||
770 | static int ovl_rmdir(struct inode *dir, struct dentry *dentry) | |
771 | { | |
772 | return ovl_do_remove(dentry, true); | |
773 | } | |
774 | ||
370e55ac MS |
775 | static bool ovl_type_merge_or_lower(struct dentry *dentry) |
776 | { | |
777 | enum ovl_path_type type = ovl_path_type(dentry); | |
778 | ||
779 | return OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type); | |
780 | } | |
781 | ||
a6c60655 MS |
782 | static bool ovl_can_move(struct dentry *dentry) |
783 | { | |
784 | return ovl_redirect_dir(dentry->d_sb) || | |
785 | !d_is_dir(dentry) || !ovl_type_merge_or_lower(dentry); | |
786 | } | |
787 | ||
a6c60655 MS |
788 | static char *ovl_get_redirect(struct dentry *dentry, bool samedir) |
789 | { | |
790 | char *buf, *ret; | |
791 | struct dentry *d, *tmp; | |
3ea22a71 | 792 | int buflen = ovl_redirect_max + 1; |
a6c60655 MS |
793 | |
794 | if (samedir) { | |
795 | ret = kstrndup(dentry->d_name.name, dentry->d_name.len, | |
796 | GFP_KERNEL); | |
797 | goto out; | |
798 | } | |
799 | ||
800 | buf = ret = kmalloc(buflen, GFP_TEMPORARY); | |
801 | if (!buf) | |
802 | goto out; | |
803 | ||
804 | buflen--; | |
805 | buf[buflen] = '\0'; | |
806 | for (d = dget(dentry); !IS_ROOT(d);) { | |
807 | const char *name; | |
808 | int thislen; | |
809 | ||
810 | spin_lock(&d->d_lock); | |
811 | name = ovl_dentry_get_redirect(d); | |
812 | if (name) { | |
813 | thislen = strlen(name); | |
814 | } else { | |
815 | name = d->d_name.name; | |
816 | thislen = d->d_name.len; | |
817 | } | |
818 | ||
819 | /* If path is too long, fall back to userspace move */ | |
820 | if (thislen + (name[0] != '/') > buflen) { | |
821 | ret = ERR_PTR(-EXDEV); | |
822 | spin_unlock(&d->d_lock); | |
823 | goto out_put; | |
824 | } | |
825 | ||
826 | buflen -= thislen; | |
827 | memcpy(&buf[buflen], name, thislen); | |
828 | tmp = dget_dlock(d->d_parent); | |
829 | spin_unlock(&d->d_lock); | |
830 | ||
831 | dput(d); | |
832 | d = tmp; | |
833 | ||
834 | /* Absolute redirect: finished */ | |
835 | if (buf[buflen] == '/') | |
836 | break; | |
837 | buflen--; | |
838 | buf[buflen] = '/'; | |
839 | } | |
840 | ret = kstrdup(&buf[buflen], GFP_KERNEL); | |
841 | out_put: | |
842 | dput(d); | |
843 | kfree(buf); | |
844 | out: | |
845 | return ret ? ret : ERR_PTR(-ENOMEM); | |
846 | } | |
847 | ||
848 | static int ovl_set_redirect(struct dentry *dentry, bool samedir) | |
849 | { | |
850 | int err; | |
851 | const char *redirect = ovl_dentry_get_redirect(dentry); | |
852 | ||
853 | if (redirect && (samedir || redirect[0] == '/')) | |
854 | return 0; | |
855 | ||
856 | redirect = ovl_get_redirect(dentry, samedir); | |
857 | if (IS_ERR(redirect)) | |
858 | return PTR_ERR(redirect); | |
859 | ||
21a22878 AG |
860 | err = ovl_check_setxattr(dentry, ovl_dentry_upper(dentry), |
861 | OVL_XATTR_REDIRECT, | |
862 | redirect, strlen(redirect), -EXDEV); | |
a6c60655 MS |
863 | if (!err) { |
864 | spin_lock(&dentry->d_lock); | |
865 | ovl_dentry_set_redirect(dentry, redirect); | |
866 | spin_unlock(&dentry->d_lock); | |
867 | } else { | |
868 | kfree(redirect); | |
21a22878 | 869 | pr_warn_ratelimited("overlay: failed to set redirect (%i)\n", err); |
a6c60655 MS |
870 | /* Fall back to userspace copy-up */ |
871 | err = -EXDEV; | |
872 | } | |
873 | return err; | |
874 | } | |
875 | ||
6c02cb59 MS |
876 | static int ovl_rename(struct inode *olddir, struct dentry *old, |
877 | struct inode *newdir, struct dentry *new, | |
878 | unsigned int flags) | |
e9be9d5e MS |
879 | { |
880 | int err; | |
e9be9d5e MS |
881 | struct dentry *old_upperdir; |
882 | struct dentry *new_upperdir; | |
883 | struct dentry *olddentry; | |
884 | struct dentry *newdentry; | |
885 | struct dentry *trap; | |
886 | bool old_opaque; | |
887 | bool new_opaque; | |
e9be9d5e MS |
888 | bool cleanup_whiteout = false; |
889 | bool overwrite = !(flags & RENAME_EXCHANGE); | |
e36cb0b8 | 890 | bool is_dir = d_is_dir(old); |
370e55ac | 891 | bool new_is_dir = d_is_dir(new); |
a6c60655 | 892 | bool samedir = olddir == newdir; |
e9be9d5e MS |
893 | struct dentry *opaquedir = NULL; |
894 | const struct cred *old_cred = NULL; | |
e9be9d5e MS |
895 | |
896 | err = -EINVAL; | |
897 | if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) | |
898 | goto out; | |
899 | ||
900 | flags &= ~RENAME_NOREPLACE; | |
901 | ||
e9be9d5e | 902 | /* Don't copy up directory trees */ |
e9be9d5e | 903 | err = -EXDEV; |
a6c60655 | 904 | if (!ovl_can_move(old)) |
370e55ac | 905 | goto out; |
a6c60655 | 906 | if (!overwrite && !ovl_can_move(new)) |
e9be9d5e | 907 | goto out; |
e9be9d5e MS |
908 | |
909 | err = ovl_want_write(old); | |
910 | if (err) | |
911 | goto out; | |
912 | ||
913 | err = ovl_copy_up(old); | |
914 | if (err) | |
915 | goto out_drop_write; | |
916 | ||
917 | err = ovl_copy_up(new->d_parent); | |
918 | if (err) | |
919 | goto out_drop_write; | |
920 | if (!overwrite) { | |
921 | err = ovl_copy_up(new); | |
922 | if (err) | |
923 | goto out_drop_write; | |
924 | } | |
925 | ||
1175b6b8 | 926 | old_cred = ovl_override_creds(old->d_sb); |
e9be9d5e | 927 | |
370e55ac | 928 | if (overwrite && new_is_dir && ovl_type_merge_or_lower(new)) { |
a105d685 | 929 | opaquedir = ovl_check_empty_and_clear(new); |
e9be9d5e MS |
930 | err = PTR_ERR(opaquedir); |
931 | if (IS_ERR(opaquedir)) { | |
932 | opaquedir = NULL; | |
933 | goto out_revert_creds; | |
934 | } | |
935 | } | |
936 | ||
937 | if (overwrite) { | |
2aff4534 | 938 | if (ovl_lower_positive(old)) { |
c412ce49 | 939 | if (!ovl_dentry_is_whiteout(new)) { |
e9be9d5e MS |
940 | /* Whiteout source */ |
941 | flags |= RENAME_WHITEOUT; | |
942 | } else { | |
943 | /* Switch whiteouts */ | |
944 | flags |= RENAME_EXCHANGE; | |
945 | } | |
c412ce49 | 946 | } else if (is_dir && ovl_dentry_is_whiteout(new)) { |
e9be9d5e MS |
947 | flags |= RENAME_EXCHANGE; |
948 | cleanup_whiteout = true; | |
949 | } | |
950 | } | |
951 | ||
952 | old_upperdir = ovl_dentry_upper(old->d_parent); | |
953 | new_upperdir = ovl_dentry_upper(new->d_parent); | |
954 | ||
955 | trap = lock_rename(new_upperdir, old_upperdir); | |
956 | ||
11f37104 MS |
957 | olddentry = lookup_one_len(old->d_name.name, old_upperdir, |
958 | old->d_name.len); | |
959 | err = PTR_ERR(olddentry); | |
960 | if (IS_ERR(olddentry)) | |
961 | goto out_unlock; | |
962 | ||
963 | err = -ESTALE; | |
964 | if (olddentry != ovl_dentry_upper(old)) | |
965 | goto out_dput_old; | |
966 | ||
967 | newdentry = lookup_one_len(new->d_name.name, new_upperdir, | |
968 | new->d_name.len); | |
969 | err = PTR_ERR(newdentry); | |
970 | if (IS_ERR(newdentry)) | |
971 | goto out_dput_old; | |
972 | ||
3ee23ff1 MS |
973 | old_opaque = ovl_dentry_is_opaque(old); |
974 | new_opaque = ovl_dentry_is_opaque(new); | |
975 | ||
11f37104 MS |
976 | err = -ESTALE; |
977 | if (ovl_dentry_upper(new)) { | |
e9be9d5e | 978 | if (opaquedir) { |
11f37104 MS |
979 | if (newdentry != opaquedir) |
980 | goto out_dput; | |
e9be9d5e | 981 | } else { |
11f37104 MS |
982 | if (newdentry != ovl_dentry_upper(new)) |
983 | goto out_dput; | |
e9be9d5e MS |
984 | } |
985 | } else { | |
11f37104 MS |
986 | if (!d_is_negative(newdentry) && |
987 | (!new_opaque || !ovl_is_whiteout(newdentry))) | |
988 | goto out_dput; | |
e9be9d5e MS |
989 | } |
990 | ||
e9be9d5e MS |
991 | if (olddentry == trap) |
992 | goto out_dput; | |
993 | if (newdentry == trap) | |
994 | goto out_dput; | |
995 | ||
804032fa MS |
996 | if (WARN_ON(olddentry->d_inode == newdentry->d_inode)) |
997 | goto out_dput; | |
998 | ||
5cf5b477 | 999 | err = 0; |
a6c60655 | 1000 | if (is_dir) { |
5cf5b477 | 1001 | if (ovl_type_merge_or_lower(old)) |
a6c60655 | 1002 | err = ovl_set_redirect(old, samedir); |
97c684cc | 1003 | else if (!old_opaque && ovl_type_merge(new->d_parent)) |
21a22878 | 1004 | err = ovl_set_opaque_xerr(old, olddentry, -EXDEV); |
5cf5b477 MS |
1005 | if (err) |
1006 | goto out_dput; | |
e9be9d5e | 1007 | } |
a6c60655 | 1008 | if (!overwrite && new_is_dir) { |
5cf5b477 | 1009 | if (ovl_type_merge_or_lower(new)) |
a6c60655 | 1010 | err = ovl_set_redirect(new, samedir); |
97c684cc | 1011 | else if (!new_opaque && ovl_type_merge(old->d_parent)) |
21a22878 | 1012 | err = ovl_set_opaque_xerr(new, newdentry, -EXDEV); |
5cf5b477 MS |
1013 | if (err) |
1014 | goto out_dput; | |
e9be9d5e MS |
1015 | } |
1016 | ||
3ee23ff1 MS |
1017 | err = ovl_do_rename(old_upperdir->d_inode, olddentry, |
1018 | new_upperdir->d_inode, newdentry, flags); | |
1019 | if (err) | |
e9be9d5e | 1020 | goto out_dput; |
e9be9d5e MS |
1021 | |
1022 | if (cleanup_whiteout) | |
1023 | ovl_cleanup(old_upperdir->d_inode, newdentry); | |
1024 | ||
1025 | ovl_dentry_version_inc(old->d_parent); | |
1026 | ovl_dentry_version_inc(new->d_parent); | |
1027 | ||
1028 | out_dput: | |
1029 | dput(newdentry); | |
11f37104 MS |
1030 | out_dput_old: |
1031 | dput(olddentry); | |
e9be9d5e MS |
1032 | out_unlock: |
1033 | unlock_rename(new_upperdir, old_upperdir); | |
1034 | out_revert_creds: | |
1175b6b8 | 1035 | revert_creds(old_cred); |
e9be9d5e MS |
1036 | out_drop_write: |
1037 | ovl_drop_write(old); | |
1038 | out: | |
1039 | dput(opaquedir); | |
1040 | return err; | |
1041 | } | |
1042 | ||
1043 | const struct inode_operations ovl_dir_inode_operations = { | |
1044 | .lookup = ovl_lookup, | |
1045 | .mkdir = ovl_mkdir, | |
1046 | .symlink = ovl_symlink, | |
1047 | .unlink = ovl_unlink, | |
1048 | .rmdir = ovl_rmdir, | |
6c02cb59 | 1049 | .rename = ovl_rename, |
e9be9d5e MS |
1050 | .link = ovl_link, |
1051 | .setattr = ovl_setattr, | |
1052 | .create = ovl_create, | |
1053 | .mknod = ovl_mknod, | |
1054 | .permission = ovl_permission, | |
5b712091 | 1055 | .getattr = ovl_getattr, |
e9be9d5e | 1056 | .listxattr = ovl_listxattr, |
39a25b2b | 1057 | .get_acl = ovl_get_acl, |
d719e8f2 | 1058 | .update_time = ovl_update_time, |
e9be9d5e | 1059 | }; |