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