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