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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, | |
85 | struct kstat *stat, const char *link, | |
86 | struct dentry *hardlink, bool debug) | |
87 | { | |
88 | int err; | |
89 | ||
90 | if (newdentry->d_inode) | |
91 | return -ESTALE; | |
92 | ||
93 | if (hardlink) { | |
94 | err = ovl_do_link(hardlink, dir, newdentry, debug); | |
95 | } else { | |
96 | switch (stat->mode & S_IFMT) { | |
97 | case S_IFREG: | |
98 | err = ovl_do_create(dir, newdentry, stat->mode, debug); | |
99 | break; | |
100 | ||
101 | case S_IFDIR: | |
102 | err = ovl_do_mkdir(dir, newdentry, stat->mode, debug); | |
103 | break; | |
104 | ||
105 | case S_IFCHR: | |
106 | case S_IFBLK: | |
107 | case S_IFIFO: | |
108 | case S_IFSOCK: | |
109 | err = ovl_do_mknod(dir, newdentry, | |
110 | stat->mode, stat->rdev, debug); | |
111 | break; | |
112 | ||
113 | case S_IFLNK: | |
114 | err = ovl_do_symlink(dir, newdentry, link, debug); | |
115 | break; | |
116 | ||
117 | default: | |
118 | err = -EPERM; | |
119 | } | |
120 | } | |
121 | if (!err && WARN_ON(!newdentry->d_inode)) { | |
122 | /* | |
123 | * Not quite sure if non-instantiated dentry is legal or not. | |
124 | * VFS doesn't seem to care so check and warn here. | |
125 | */ | |
126 | err = -ENOENT; | |
127 | } | |
128 | return err; | |
129 | } | |
130 | ||
5cf5b477 | 131 | static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry) |
e9be9d5e | 132 | { |
5cf5b477 MS |
133 | int err; |
134 | ||
135 | err = ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0); | |
136 | if (!err) | |
137 | ovl_dentry_set_opaque(dentry); | |
138 | ||
139 | return err; | |
e9be9d5e MS |
140 | } |
141 | ||
e9be9d5e MS |
142 | static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry, |
143 | struct kstat *stat) | |
144 | { | |
145 | int err; | |
146 | enum ovl_path_type type; | |
147 | struct path realpath; | |
1175b6b8 | 148 | const struct cred *old_cred; |
e9be9d5e MS |
149 | |
150 | type = ovl_path_real(dentry, &realpath); | |
1175b6b8 | 151 | old_cred = ovl_override_creds(dentry->d_sb); |
e9be9d5e | 152 | err = vfs_getattr(&realpath, stat); |
1175b6b8 | 153 | revert_creds(old_cred); |
e9be9d5e MS |
154 | if (err) |
155 | return err; | |
156 | ||
157 | stat->dev = dentry->d_sb->s_dev; | |
158 | stat->ino = dentry->d_inode->i_ino; | |
159 | ||
160 | /* | |
161 | * It's probably not worth it to count subdirs to get the | |
162 | * correct link count. nlink=1 seems to pacify 'find' and | |
163 | * other utilities. | |
164 | */ | |
1afaba1e | 165 | if (OVL_TYPE_MERGE(type)) |
e9be9d5e MS |
166 | stat->nlink = 1; |
167 | ||
168 | return 0; | |
169 | } | |
170 | ||
72e48481 VG |
171 | /* Common operations required to be done after creation of file on upper */ |
172 | static void ovl_instantiate(struct dentry *dentry, struct inode *inode, | |
51f7e52d | 173 | struct dentry *newdentry, bool hardlink) |
72e48481 VG |
174 | { |
175 | ovl_dentry_version_inc(dentry->d_parent); | |
176 | ovl_dentry_update(dentry, newdentry); | |
51f7e52d MS |
177 | if (!hardlink) { |
178 | ovl_inode_update(inode, d_inode(newdentry)); | |
179 | ovl_copyattr(newdentry->d_inode, inode); | |
180 | } else { | |
181 | WARN_ON(ovl_inode_real(inode, NULL) != d_inode(newdentry)); | |
182 | inc_nlink(inode); | |
183 | } | |
72e48481 VG |
184 | d_instantiate(dentry, inode); |
185 | } | |
186 | ||
e9be9d5e MS |
187 | static int ovl_create_upper(struct dentry *dentry, struct inode *inode, |
188 | struct kstat *stat, const char *link, | |
189 | struct dentry *hardlink) | |
190 | { | |
191 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
192 | struct inode *udir = upperdir->d_inode; | |
193 | struct dentry *newdentry; | |
194 | int err; | |
195 | ||
38b25697 MS |
196 | if (!hardlink && !IS_POSIXACL(udir)) |
197 | stat->mode &= ~current_umask(); | |
198 | ||
5955102c | 199 | inode_lock_nested(udir, I_MUTEX_PARENT); |
e9be9d5e MS |
200 | newdentry = lookup_one_len(dentry->d_name.name, upperdir, |
201 | dentry->d_name.len); | |
202 | err = PTR_ERR(newdentry); | |
203 | if (IS_ERR(newdentry)) | |
204 | goto out_unlock; | |
205 | err = ovl_create_real(udir, newdentry, stat, link, hardlink, false); | |
206 | if (err) | |
207 | goto out_dput; | |
208 | ||
51f7e52d | 209 | ovl_instantiate(dentry, inode, newdentry, !!hardlink); |
e9be9d5e MS |
210 | newdentry = NULL; |
211 | out_dput: | |
212 | dput(newdentry); | |
213 | out_unlock: | |
5955102c | 214 | inode_unlock(udir); |
e9be9d5e MS |
215 | return err; |
216 | } | |
217 | ||
218 | static int ovl_lock_rename_workdir(struct dentry *workdir, | |
219 | struct dentry *upperdir) | |
220 | { | |
221 | /* Workdir should not be the same as upperdir */ | |
222 | if (workdir == upperdir) | |
223 | goto err; | |
224 | ||
225 | /* Workdir should not be subdir of upperdir and vice versa */ | |
226 | if (lock_rename(workdir, upperdir) != NULL) | |
227 | goto err_unlock; | |
228 | ||
229 | return 0; | |
230 | ||
231 | err_unlock: | |
232 | unlock_rename(workdir, upperdir); | |
233 | err: | |
234 | pr_err("overlayfs: failed to lock workdir+upperdir\n"); | |
235 | return -EIO; | |
236 | } | |
237 | ||
238 | static struct dentry *ovl_clear_empty(struct dentry *dentry, | |
239 | struct list_head *list) | |
240 | { | |
241 | struct dentry *workdir = ovl_workdir(dentry); | |
242 | struct inode *wdir = workdir->d_inode; | |
243 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
244 | struct inode *udir = upperdir->d_inode; | |
245 | struct path upperpath; | |
246 | struct dentry *upper; | |
247 | struct dentry *opaquedir; | |
248 | struct kstat stat; | |
249 | int err; | |
250 | ||
cc6f67bc MS |
251 | if (WARN_ON(!workdir)) |
252 | return ERR_PTR(-EROFS); | |
253 | ||
e9be9d5e MS |
254 | err = ovl_lock_rename_workdir(workdir, upperdir); |
255 | if (err) | |
256 | goto out; | |
257 | ||
258 | ovl_path_upper(dentry, &upperpath); | |
259 | err = vfs_getattr(&upperpath, &stat); | |
260 | if (err) | |
261 | goto out_unlock; | |
262 | ||
263 | err = -ESTALE; | |
264 | if (!S_ISDIR(stat.mode)) | |
265 | goto out_unlock; | |
266 | upper = upperpath.dentry; | |
267 | if (upper->d_parent->d_inode != udir) | |
268 | goto out_unlock; | |
269 | ||
270 | opaquedir = ovl_lookup_temp(workdir, dentry); | |
271 | err = PTR_ERR(opaquedir); | |
272 | if (IS_ERR(opaquedir)) | |
273 | goto out_unlock; | |
274 | ||
275 | err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true); | |
276 | if (err) | |
277 | goto out_dput; | |
278 | ||
279 | err = ovl_copy_xattr(upper, opaquedir); | |
280 | if (err) | |
281 | goto out_cleanup; | |
282 | ||
5cf5b477 | 283 | err = ovl_set_opaque(dentry, opaquedir); |
e9be9d5e MS |
284 | if (err) |
285 | goto out_cleanup; | |
286 | ||
5955102c | 287 | inode_lock(opaquedir->d_inode); |
e9be9d5e | 288 | err = ovl_set_attr(opaquedir, &stat); |
5955102c | 289 | inode_unlock(opaquedir->d_inode); |
e9be9d5e MS |
290 | if (err) |
291 | goto out_cleanup; | |
292 | ||
293 | err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE); | |
294 | if (err) | |
295 | goto out_cleanup; | |
296 | ||
297 | ovl_cleanup_whiteouts(upper, list); | |
298 | ovl_cleanup(wdir, upper); | |
299 | unlock_rename(workdir, upperdir); | |
300 | ||
301 | /* dentry's upper doesn't match now, get rid of it */ | |
302 | d_drop(dentry); | |
303 | ||
304 | return opaquedir; | |
305 | ||
306 | out_cleanup: | |
307 | ovl_cleanup(wdir, opaquedir); | |
308 | out_dput: | |
309 | dput(opaquedir); | |
310 | out_unlock: | |
311 | unlock_rename(workdir, upperdir); | |
312 | out: | |
313 | return ERR_PTR(err); | |
314 | } | |
315 | ||
a105d685 | 316 | static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry) |
e9be9d5e MS |
317 | { |
318 | int err; | |
319 | struct dentry *ret = NULL; | |
30c17ebf | 320 | enum ovl_path_type type = ovl_path_type(dentry); |
e9be9d5e MS |
321 | LIST_HEAD(list); |
322 | ||
323 | err = ovl_check_empty_dir(dentry, &list); | |
30c17ebf | 324 | if (err) { |
e9be9d5e | 325 | ret = ERR_PTR(err); |
30c17ebf | 326 | goto out_free; |
a105d685 | 327 | } |
e9be9d5e | 328 | |
30c17ebf MS |
329 | /* |
330 | * When removing an empty opaque directory, then it makes no sense to | |
331 | * replace it with an exact replica of itself. | |
332 | * | |
333 | * If no upperdentry then skip clearing whiteouts. | |
334 | * | |
335 | * Can race with copy-up, since we don't hold the upperdir mutex. | |
336 | * Doesn't matter, since copy-up can't create a non-empty directory | |
337 | * from an empty one. | |
338 | */ | |
339 | if (OVL_TYPE_UPPER(type) && OVL_TYPE_MERGE(type)) | |
340 | ret = ovl_clear_empty(dentry, &list); | |
341 | ||
342 | out_free: | |
e9be9d5e MS |
343 | ovl_cache_free(&list); |
344 | ||
345 | return ret; | |
346 | } | |
347 | ||
38b25697 MS |
348 | static int ovl_set_upper_acl(struct dentry *upperdentry, const char *name, |
349 | const struct posix_acl *acl) | |
350 | { | |
351 | void *buffer; | |
352 | size_t size; | |
353 | int err; | |
354 | ||
355 | if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !acl) | |
356 | return 0; | |
357 | ||
358 | size = posix_acl_to_xattr(NULL, acl, NULL, 0); | |
359 | buffer = kmalloc(size, GFP_KERNEL); | |
360 | if (!buffer) | |
361 | return -ENOMEM; | |
362 | ||
363 | size = posix_acl_to_xattr(&init_user_ns, acl, buffer, size); | |
364 | err = size; | |
365 | if (err < 0) | |
366 | goto out_free; | |
367 | ||
368 | err = vfs_setxattr(upperdentry, name, buffer, size, XATTR_CREATE); | |
369 | out_free: | |
370 | kfree(buffer); | |
371 | return err; | |
372 | } | |
373 | ||
e9be9d5e MS |
374 | static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, |
375 | struct kstat *stat, const char *link, | |
376 | struct dentry *hardlink) | |
377 | { | |
378 | struct dentry *workdir = ovl_workdir(dentry); | |
379 | struct inode *wdir = workdir->d_inode; | |
380 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
381 | struct inode *udir = upperdir->d_inode; | |
382 | struct dentry *upper; | |
383 | struct dentry *newdentry; | |
384 | int err; | |
38b25697 | 385 | struct posix_acl *acl, *default_acl; |
e9be9d5e | 386 | |
cc6f67bc MS |
387 | if (WARN_ON(!workdir)) |
388 | return -EROFS; | |
389 | ||
38b25697 MS |
390 | if (!hardlink) { |
391 | err = posix_acl_create(dentry->d_parent->d_inode, | |
392 | &stat->mode, &default_acl, &acl); | |
393 | if (err) | |
394 | return err; | |
395 | } | |
396 | ||
e9be9d5e MS |
397 | err = ovl_lock_rename_workdir(workdir, upperdir); |
398 | if (err) | |
399 | goto out; | |
400 | ||
401 | newdentry = ovl_lookup_temp(workdir, dentry); | |
402 | err = PTR_ERR(newdentry); | |
403 | if (IS_ERR(newdentry)) | |
404 | goto out_unlock; | |
405 | ||
406 | upper = lookup_one_len(dentry->d_name.name, upperdir, | |
407 | dentry->d_name.len); | |
408 | err = PTR_ERR(upper); | |
409 | if (IS_ERR(upper)) | |
410 | goto out_dput; | |
411 | ||
412 | err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true); | |
413 | if (err) | |
414 | goto out_dput2; | |
415 | ||
bb0d2b8a MS |
416 | /* |
417 | * mode could have been mutilated due to umask (e.g. sgid directory) | |
418 | */ | |
51f7e52d MS |
419 | if (!hardlink && |
420 | !S_ISLNK(stat->mode) && newdentry->d_inode->i_mode != stat->mode) { | |
bb0d2b8a MS |
421 | struct iattr attr = { |
422 | .ia_valid = ATTR_MODE, | |
423 | .ia_mode = stat->mode, | |
424 | }; | |
425 | inode_lock(newdentry->d_inode); | |
426 | err = notify_change(newdentry, &attr, NULL); | |
427 | inode_unlock(newdentry->d_inode); | |
428 | if (err) | |
429 | goto out_cleanup; | |
430 | } | |
38b25697 MS |
431 | if (!hardlink) { |
432 | err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS, | |
433 | acl); | |
434 | if (err) | |
435 | goto out_cleanup; | |
436 | ||
437 | err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT, | |
438 | default_acl); | |
439 | if (err) | |
440 | goto out_cleanup; | |
441 | } | |
bb0d2b8a | 442 | |
51f7e52d | 443 | if (!hardlink && S_ISDIR(stat->mode)) { |
5cf5b477 | 444 | err = ovl_set_opaque(dentry, newdentry); |
e9be9d5e MS |
445 | if (err) |
446 | goto out_cleanup; | |
447 | ||
448 | err = ovl_do_rename(wdir, newdentry, udir, upper, | |
449 | RENAME_EXCHANGE); | |
450 | if (err) | |
451 | goto out_cleanup; | |
452 | ||
453 | ovl_cleanup(wdir, upper); | |
454 | } else { | |
455 | err = ovl_do_rename(wdir, newdentry, udir, upper, 0); | |
456 | if (err) | |
457 | goto out_cleanup; | |
458 | } | |
51f7e52d | 459 | ovl_instantiate(dentry, inode, newdentry, !!hardlink); |
e9be9d5e MS |
460 | newdentry = NULL; |
461 | out_dput2: | |
462 | dput(upper); | |
463 | out_dput: | |
464 | dput(newdentry); | |
465 | out_unlock: | |
466 | unlock_rename(workdir, upperdir); | |
467 | out: | |
38b25697 MS |
468 | if (!hardlink) { |
469 | posix_acl_release(acl); | |
470 | posix_acl_release(default_acl); | |
471 | } | |
e9be9d5e MS |
472 | return err; |
473 | ||
474 | out_cleanup: | |
475 | ovl_cleanup(wdir, newdentry); | |
476 | goto out_dput2; | |
477 | } | |
478 | ||
51f7e52d MS |
479 | static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, |
480 | struct kstat *stat, const char *link, | |
481 | struct dentry *hardlink) | |
e9be9d5e MS |
482 | { |
483 | int err; | |
1175b6b8 VG |
484 | const struct cred *old_cred; |
485 | struct cred *override_cred; | |
e9be9d5e MS |
486 | |
487 | err = ovl_copy_up(dentry->d_parent); | |
488 | if (err) | |
51f7e52d | 489 | return err; |
bb0d2b8a | 490 | |
1175b6b8 VG |
491 | old_cred = ovl_override_creds(dentry->d_sb); |
492 | err = -ENOMEM; | |
493 | override_cred = prepare_creds(); | |
494 | if (override_cred) { | |
bb0d2b8a MS |
495 | override_cred->fsuid = inode->i_uid; |
496 | override_cred->fsgid = inode->i_gid; | |
2602625b VG |
497 | if (!hardlink) { |
498 | err = security_dentry_create_files_as(dentry, | |
499 | stat->mode, &dentry->d_name, old_cred, | |
500 | override_cred); | |
501 | if (err) { | |
502 | put_cred(override_cred); | |
503 | goto out_revert_creds; | |
504 | } | |
505 | } | |
1175b6b8 VG |
506 | put_cred(override_creds(override_cred)); |
507 | put_cred(override_cred); | |
508 | ||
c412ce49 | 509 | if (!ovl_dentry_is_whiteout(dentry)) |
51f7e52d | 510 | err = ovl_create_upper(dentry, inode, stat, link, |
1175b6b8 VG |
511 | hardlink); |
512 | else | |
51f7e52d | 513 | err = ovl_create_over_whiteout(dentry, inode, stat, |
1175b6b8 | 514 | link, hardlink); |
e9be9d5e | 515 | } |
2602625b | 516 | out_revert_creds: |
1175b6b8 | 517 | revert_creds(old_cred); |
bb0d2b8a MS |
518 | if (!err) { |
519 | struct inode *realinode = d_inode(ovl_dentry_upper(dentry)); | |
520 | ||
521 | WARN_ON(inode->i_mode != realinode->i_mode); | |
522 | WARN_ON(!uid_eq(inode->i_uid, realinode->i_uid)); | |
523 | WARN_ON(!gid_eq(inode->i_gid, realinode->i_gid)); | |
bb0d2b8a | 524 | } |
e9be9d5e MS |
525 | return err; |
526 | } | |
527 | ||
528 | static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev, | |
529 | const char *link) | |
530 | { | |
531 | int err; | |
51f7e52d MS |
532 | struct inode *inode; |
533 | struct kstat stat = { | |
534 | .rdev = rdev, | |
535 | }; | |
e9be9d5e MS |
536 | |
537 | err = ovl_want_write(dentry); | |
51f7e52d MS |
538 | if (err) |
539 | goto out; | |
540 | ||
541 | err = -ENOMEM; | |
ca4c8a3a | 542 | inode = ovl_new_inode(dentry->d_sb, mode, rdev); |
51f7e52d MS |
543 | if (!inode) |
544 | goto out_drop_write; | |
545 | ||
546 | inode_init_owner(inode, dentry->d_parent->d_inode, mode); | |
547 | stat.mode = inode->i_mode; | |
548 | ||
549 | err = ovl_create_or_link(dentry, inode, &stat, link, NULL); | |
550 | if (err) | |
551 | iput(inode); | |
e9be9d5e | 552 | |
51f7e52d MS |
553 | out_drop_write: |
554 | ovl_drop_write(dentry); | |
555 | out: | |
e9be9d5e MS |
556 | return err; |
557 | } | |
558 | ||
559 | static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode, | |
560 | bool excl) | |
561 | { | |
562 | return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL); | |
563 | } | |
564 | ||
565 | static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) | |
566 | { | |
567 | return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL); | |
568 | } | |
569 | ||
570 | static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, | |
571 | dev_t rdev) | |
572 | { | |
573 | /* Don't allow creation of "whiteout" on overlay */ | |
574 | if (S_ISCHR(mode) && rdev == WHITEOUT_DEV) | |
575 | return -EPERM; | |
576 | ||
577 | return ovl_create_object(dentry, mode, rdev, NULL); | |
578 | } | |
579 | ||
580 | static int ovl_symlink(struct inode *dir, struct dentry *dentry, | |
581 | const char *link) | |
582 | { | |
583 | return ovl_create_object(dentry, S_IFLNK, 0, link); | |
584 | } | |
585 | ||
586 | static int ovl_link(struct dentry *old, struct inode *newdir, | |
587 | struct dentry *new) | |
588 | { | |
589 | int err; | |
51f7e52d | 590 | struct inode *inode; |
e9be9d5e MS |
591 | |
592 | err = ovl_want_write(old); | |
593 | if (err) | |
594 | goto out; | |
595 | ||
596 | err = ovl_copy_up(old); | |
597 | if (err) | |
598 | goto out_drop_write; | |
599 | ||
51f7e52d MS |
600 | inode = d_inode(old); |
601 | ihold(inode); | |
602 | ||
603 | err = ovl_create_or_link(new, inode, NULL, NULL, ovl_dentry_upper(old)); | |
604 | if (err) | |
605 | iput(inode); | |
e9be9d5e MS |
606 | |
607 | out_drop_write: | |
608 | ovl_drop_write(old); | |
609 | out: | |
610 | return err; | |
611 | } | |
612 | ||
a105d685 | 613 | static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir) |
e9be9d5e MS |
614 | { |
615 | struct dentry *workdir = ovl_workdir(dentry); | |
616 | struct inode *wdir = workdir->d_inode; | |
617 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
618 | struct inode *udir = upperdir->d_inode; | |
619 | struct dentry *whiteout; | |
620 | struct dentry *upper; | |
621 | struct dentry *opaquedir = NULL; | |
622 | int err; | |
cfc9fde0 | 623 | int flags = 0; |
e9be9d5e | 624 | |
cc6f67bc MS |
625 | if (WARN_ON(!workdir)) |
626 | return -EROFS; | |
627 | ||
d377c5eb | 628 | if (is_dir) { |
30c17ebf MS |
629 | opaquedir = ovl_check_empty_and_clear(dentry); |
630 | err = PTR_ERR(opaquedir); | |
631 | if (IS_ERR(opaquedir)) | |
632 | goto out; | |
e9be9d5e MS |
633 | } |
634 | ||
635 | err = ovl_lock_rename_workdir(workdir, upperdir); | |
636 | if (err) | |
637 | goto out_dput; | |
638 | ||
cfc9fde0 MP |
639 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
640 | dentry->d_name.len); | |
641 | err = PTR_ERR(upper); | |
642 | if (IS_ERR(upper)) | |
e9be9d5e MS |
643 | goto out_unlock; |
644 | ||
cfc9fde0 MP |
645 | err = -ESTALE; |
646 | if ((opaquedir && upper != opaquedir) || | |
647 | (!opaquedir && ovl_dentry_upper(dentry) && | |
648 | upper != ovl_dentry_upper(dentry))) { | |
649 | goto out_dput_upper; | |
650 | } | |
e9be9d5e | 651 | |
cfc9fde0 MP |
652 | whiteout = ovl_whiteout(workdir, dentry); |
653 | err = PTR_ERR(whiteout); | |
654 | if (IS_ERR(whiteout)) | |
655 | goto out_dput_upper; | |
e9be9d5e | 656 | |
cfc9fde0 MP |
657 | if (d_is_dir(upper)) |
658 | flags = RENAME_EXCHANGE; | |
e9be9d5e | 659 | |
cfc9fde0 MP |
660 | err = ovl_do_rename(wdir, whiteout, udir, upper, flags); |
661 | if (err) | |
662 | goto kill_whiteout; | |
663 | if (flags) | |
664 | ovl_cleanup(wdir, upper); | |
e9be9d5e | 665 | |
e9be9d5e MS |
666 | ovl_dentry_version_inc(dentry->d_parent); |
667 | out_d_drop: | |
668 | d_drop(dentry); | |
669 | dput(whiteout); | |
cfc9fde0 MP |
670 | out_dput_upper: |
671 | dput(upper); | |
e9be9d5e MS |
672 | out_unlock: |
673 | unlock_rename(workdir, upperdir); | |
674 | out_dput: | |
675 | dput(opaquedir); | |
676 | out: | |
677 | return err; | |
678 | ||
679 | kill_whiteout: | |
680 | ovl_cleanup(wdir, whiteout); | |
681 | goto out_d_drop; | |
682 | } | |
683 | ||
684 | static int ovl_remove_upper(struct dentry *dentry, bool is_dir) | |
685 | { | |
686 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
687 | struct inode *dir = upperdir->d_inode; | |
11f37104 | 688 | struct dentry *upper; |
d1595119 | 689 | struct dentry *opaquedir = NULL; |
e9be9d5e MS |
690 | int err; |
691 | ||
d1595119 AG |
692 | /* Redirect dir can be !ovl_lower_positive && OVL_TYPE_MERGE */ |
693 | if (is_dir && ovl_dentry_get_redirect(dentry)) { | |
694 | opaquedir = ovl_check_empty_and_clear(dentry); | |
695 | err = PTR_ERR(opaquedir); | |
696 | if (IS_ERR(opaquedir)) | |
697 | goto out; | |
698 | } | |
699 | ||
5955102c | 700 | inode_lock_nested(dir, I_MUTEX_PARENT); |
11f37104 MS |
701 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
702 | dentry->d_name.len); | |
703 | err = PTR_ERR(upper); | |
704 | if (IS_ERR(upper)) | |
705 | goto out_unlock; | |
706 | ||
e9be9d5e | 707 | err = -ESTALE; |
d1595119 AG |
708 | if ((opaquedir && upper != opaquedir) || |
709 | (!opaquedir && upper != ovl_dentry_upper(dentry))) | |
710 | goto out_dput_upper; | |
711 | ||
712 | if (is_dir) | |
713 | err = vfs_rmdir(dir, upper); | |
714 | else | |
715 | err = vfs_unlink(dir, upper, NULL); | |
716 | ovl_dentry_version_inc(dentry->d_parent); | |
e9be9d5e MS |
717 | |
718 | /* | |
719 | * Keeping this dentry hashed would mean having to release | |
720 | * upperpath/lowerpath, which could only be done if we are the | |
721 | * sole user of this dentry. Too tricky... Just unhash for | |
722 | * now. | |
723 | */ | |
ce9113bb RW |
724 | if (!err) |
725 | d_drop(dentry); | |
d1595119 AG |
726 | out_dput_upper: |
727 | dput(upper); | |
11f37104 | 728 | out_unlock: |
5955102c | 729 | inode_unlock(dir); |
d1595119 AG |
730 | dput(opaquedir); |
731 | out: | |
e9be9d5e MS |
732 | return err; |
733 | } | |
734 | ||
e9be9d5e MS |
735 | static int ovl_do_remove(struct dentry *dentry, bool is_dir) |
736 | { | |
737 | enum ovl_path_type type; | |
738 | int err; | |
1175b6b8 VG |
739 | const struct cred *old_cred; |
740 | ||
e9be9d5e MS |
741 | err = ovl_want_write(dentry); |
742 | if (err) | |
743 | goto out; | |
744 | ||
745 | err = ovl_copy_up(dentry->d_parent); | |
746 | if (err) | |
747 | goto out_drop_write; | |
748 | ||
749 | type = ovl_path_type(dentry); | |
e9be9d5e | 750 | |
1175b6b8 | 751 | old_cred = ovl_override_creds(dentry->d_sb); |
2aff4534 | 752 | if (!ovl_lower_positive(dentry)) |
1175b6b8 VG |
753 | err = ovl_remove_upper(dentry, is_dir); |
754 | else | |
a105d685 | 755 | err = ovl_remove_and_whiteout(dentry, is_dir); |
1175b6b8 | 756 | revert_creds(old_cred); |
dbc816d0 MS |
757 | if (!err) { |
758 | if (is_dir) | |
759 | clear_nlink(dentry->d_inode); | |
760 | else | |
761 | drop_nlink(dentry->d_inode); | |
762 | } | |
e9be9d5e MS |
763 | out_drop_write: |
764 | ovl_drop_write(dentry); | |
765 | out: | |
766 | return err; | |
767 | } | |
768 | ||
769 | static int ovl_unlink(struct inode *dir, struct dentry *dentry) | |
770 | { | |
771 | return ovl_do_remove(dentry, false); | |
772 | } | |
773 | ||
774 | static int ovl_rmdir(struct inode *dir, struct dentry *dentry) | |
775 | { | |
776 | return ovl_do_remove(dentry, true); | |
777 | } | |
778 | ||
370e55ac MS |
779 | static bool ovl_type_merge_or_lower(struct dentry *dentry) |
780 | { | |
781 | enum ovl_path_type type = ovl_path_type(dentry); | |
782 | ||
783 | return OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type); | |
784 | } | |
785 | ||
a6c60655 MS |
786 | static bool ovl_can_move(struct dentry *dentry) |
787 | { | |
788 | return ovl_redirect_dir(dentry->d_sb) || | |
789 | !d_is_dir(dentry) || !ovl_type_merge_or_lower(dentry); | |
790 | } | |
791 | ||
a6c60655 MS |
792 | static char *ovl_get_redirect(struct dentry *dentry, bool samedir) |
793 | { | |
794 | char *buf, *ret; | |
795 | struct dentry *d, *tmp; | |
3ea22a71 | 796 | int buflen = ovl_redirect_max + 1; |
a6c60655 MS |
797 | |
798 | if (samedir) { | |
799 | ret = kstrndup(dentry->d_name.name, dentry->d_name.len, | |
800 | GFP_KERNEL); | |
801 | goto out; | |
802 | } | |
803 | ||
804 | buf = ret = kmalloc(buflen, GFP_TEMPORARY); | |
805 | if (!buf) | |
806 | goto out; | |
807 | ||
808 | buflen--; | |
809 | buf[buflen] = '\0'; | |
810 | for (d = dget(dentry); !IS_ROOT(d);) { | |
811 | const char *name; | |
812 | int thislen; | |
813 | ||
814 | spin_lock(&d->d_lock); | |
815 | name = ovl_dentry_get_redirect(d); | |
816 | if (name) { | |
817 | thislen = strlen(name); | |
818 | } else { | |
819 | name = d->d_name.name; | |
820 | thislen = d->d_name.len; | |
821 | } | |
822 | ||
823 | /* If path is too long, fall back to userspace move */ | |
824 | if (thislen + (name[0] != '/') > buflen) { | |
825 | ret = ERR_PTR(-EXDEV); | |
826 | spin_unlock(&d->d_lock); | |
827 | goto out_put; | |
828 | } | |
829 | ||
830 | buflen -= thislen; | |
831 | memcpy(&buf[buflen], name, thislen); | |
832 | tmp = dget_dlock(d->d_parent); | |
833 | spin_unlock(&d->d_lock); | |
834 | ||
835 | dput(d); | |
836 | d = tmp; | |
837 | ||
838 | /* Absolute redirect: finished */ | |
839 | if (buf[buflen] == '/') | |
840 | break; | |
841 | buflen--; | |
842 | buf[buflen] = '/'; | |
843 | } | |
844 | ret = kstrdup(&buf[buflen], GFP_KERNEL); | |
845 | out_put: | |
846 | dput(d); | |
847 | kfree(buf); | |
848 | out: | |
849 | return ret ? ret : ERR_PTR(-ENOMEM); | |
850 | } | |
851 | ||
852 | static int ovl_set_redirect(struct dentry *dentry, bool samedir) | |
853 | { | |
854 | int err; | |
855 | const char *redirect = ovl_dentry_get_redirect(dentry); | |
856 | ||
857 | if (redirect && (samedir || redirect[0] == '/')) | |
858 | return 0; | |
859 | ||
860 | redirect = ovl_get_redirect(dentry, samedir); | |
861 | if (IS_ERR(redirect)) | |
862 | return PTR_ERR(redirect); | |
863 | ||
864 | err = ovl_do_setxattr(ovl_dentry_upper(dentry), OVL_XATTR_REDIRECT, | |
865 | redirect, strlen(redirect), 0); | |
866 | if (!err) { | |
867 | spin_lock(&dentry->d_lock); | |
868 | ovl_dentry_set_redirect(dentry, redirect); | |
869 | spin_unlock(&dentry->d_lock); | |
870 | } else { | |
871 | kfree(redirect); | |
872 | if (err == -EOPNOTSUPP) | |
873 | ovl_clear_redirect_dir(dentry->d_sb); | |
874 | else | |
875 | pr_warn_ratelimited("overlay: failed to set redirect (%i)\n", err); | |
876 | /* Fall back to userspace copy-up */ | |
877 | err = -EXDEV; | |
878 | } | |
879 | return err; | |
880 | } | |
881 | ||
6c02cb59 MS |
882 | static int ovl_rename(struct inode *olddir, struct dentry *old, |
883 | struct inode *newdir, struct dentry *new, | |
884 | unsigned int flags) | |
e9be9d5e MS |
885 | { |
886 | int err; | |
e9be9d5e MS |
887 | struct dentry *old_upperdir; |
888 | struct dentry *new_upperdir; | |
889 | struct dentry *olddentry; | |
890 | struct dentry *newdentry; | |
891 | struct dentry *trap; | |
892 | bool old_opaque; | |
893 | bool new_opaque; | |
e9be9d5e MS |
894 | bool cleanup_whiteout = false; |
895 | bool overwrite = !(flags & RENAME_EXCHANGE); | |
e36cb0b8 | 896 | bool is_dir = d_is_dir(old); |
370e55ac | 897 | bool new_is_dir = d_is_dir(new); |
a6c60655 | 898 | bool samedir = olddir == newdir; |
e9be9d5e MS |
899 | struct dentry *opaquedir = NULL; |
900 | const struct cred *old_cred = NULL; | |
e9be9d5e MS |
901 | |
902 | err = -EINVAL; | |
903 | if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) | |
904 | goto out; | |
905 | ||
906 | flags &= ~RENAME_NOREPLACE; | |
907 | ||
e9be9d5e | 908 | /* Don't copy up directory trees */ |
e9be9d5e | 909 | err = -EXDEV; |
a6c60655 | 910 | if (!ovl_can_move(old)) |
370e55ac | 911 | goto out; |
a6c60655 | 912 | if (!overwrite && !ovl_can_move(new)) |
e9be9d5e | 913 | goto out; |
e9be9d5e MS |
914 | |
915 | err = ovl_want_write(old); | |
916 | if (err) | |
917 | goto out; | |
918 | ||
919 | err = ovl_copy_up(old); | |
920 | if (err) | |
921 | goto out_drop_write; | |
922 | ||
923 | err = ovl_copy_up(new->d_parent); | |
924 | if (err) | |
925 | goto out_drop_write; | |
926 | if (!overwrite) { | |
927 | err = ovl_copy_up(new); | |
928 | if (err) | |
929 | goto out_drop_write; | |
930 | } | |
931 | ||
1175b6b8 | 932 | old_cred = ovl_override_creds(old->d_sb); |
e9be9d5e | 933 | |
370e55ac | 934 | if (overwrite && new_is_dir && ovl_type_merge_or_lower(new)) { |
a105d685 | 935 | opaquedir = ovl_check_empty_and_clear(new); |
e9be9d5e MS |
936 | err = PTR_ERR(opaquedir); |
937 | if (IS_ERR(opaquedir)) { | |
938 | opaquedir = NULL; | |
939 | goto out_revert_creds; | |
940 | } | |
941 | } | |
942 | ||
943 | if (overwrite) { | |
2aff4534 | 944 | if (ovl_lower_positive(old)) { |
c412ce49 | 945 | if (!ovl_dentry_is_whiteout(new)) { |
e9be9d5e MS |
946 | /* Whiteout source */ |
947 | flags |= RENAME_WHITEOUT; | |
948 | } else { | |
949 | /* Switch whiteouts */ | |
950 | flags |= RENAME_EXCHANGE; | |
951 | } | |
c412ce49 | 952 | } else if (is_dir && ovl_dentry_is_whiteout(new)) { |
e9be9d5e MS |
953 | flags |= RENAME_EXCHANGE; |
954 | cleanup_whiteout = true; | |
955 | } | |
956 | } | |
957 | ||
958 | old_upperdir = ovl_dentry_upper(old->d_parent); | |
959 | new_upperdir = ovl_dentry_upper(new->d_parent); | |
960 | ||
961 | trap = lock_rename(new_upperdir, old_upperdir); | |
962 | ||
11f37104 MS |
963 | olddentry = lookup_one_len(old->d_name.name, old_upperdir, |
964 | old->d_name.len); | |
965 | err = PTR_ERR(olddentry); | |
966 | if (IS_ERR(olddentry)) | |
967 | goto out_unlock; | |
968 | ||
969 | err = -ESTALE; | |
970 | if (olddentry != ovl_dentry_upper(old)) | |
971 | goto out_dput_old; | |
972 | ||
973 | newdentry = lookup_one_len(new->d_name.name, new_upperdir, | |
974 | new->d_name.len); | |
975 | err = PTR_ERR(newdentry); | |
976 | if (IS_ERR(newdentry)) | |
977 | goto out_dput_old; | |
978 | ||
3ee23ff1 MS |
979 | old_opaque = ovl_dentry_is_opaque(old); |
980 | new_opaque = ovl_dentry_is_opaque(new); | |
981 | ||
11f37104 MS |
982 | err = -ESTALE; |
983 | if (ovl_dentry_upper(new)) { | |
e9be9d5e | 984 | if (opaquedir) { |
11f37104 MS |
985 | if (newdentry != opaquedir) |
986 | goto out_dput; | |
e9be9d5e | 987 | } else { |
11f37104 MS |
988 | if (newdentry != ovl_dentry_upper(new)) |
989 | goto out_dput; | |
e9be9d5e MS |
990 | } |
991 | } else { | |
11f37104 MS |
992 | if (!d_is_negative(newdentry) && |
993 | (!new_opaque || !ovl_is_whiteout(newdentry))) | |
994 | goto out_dput; | |
e9be9d5e MS |
995 | } |
996 | ||
e9be9d5e MS |
997 | if (olddentry == trap) |
998 | goto out_dput; | |
999 | if (newdentry == trap) | |
1000 | goto out_dput; | |
1001 | ||
804032fa MS |
1002 | if (WARN_ON(olddentry->d_inode == newdentry->d_inode)) |
1003 | goto out_dput; | |
1004 | ||
5cf5b477 | 1005 | err = 0; |
a6c60655 | 1006 | if (is_dir) { |
5cf5b477 | 1007 | if (ovl_type_merge_or_lower(old)) |
a6c60655 | 1008 | err = ovl_set_redirect(old, samedir); |
5cf5b477 MS |
1009 | else if (!old_opaque && ovl_lower_positive(new)) |
1010 | err = ovl_set_opaque(old, olddentry); | |
1011 | if (err) | |
1012 | goto out_dput; | |
e9be9d5e | 1013 | } |
a6c60655 | 1014 | if (!overwrite && new_is_dir) { |
5cf5b477 | 1015 | if (ovl_type_merge_or_lower(new)) |
a6c60655 | 1016 | err = ovl_set_redirect(new, samedir); |
5cf5b477 MS |
1017 | else if (!new_opaque && ovl_lower_positive(old)) |
1018 | err = ovl_set_opaque(new, newdentry); | |
1019 | if (err) | |
1020 | goto out_dput; | |
e9be9d5e MS |
1021 | } |
1022 | ||
3ee23ff1 MS |
1023 | err = ovl_do_rename(old_upperdir->d_inode, olddentry, |
1024 | new_upperdir->d_inode, newdentry, flags); | |
1025 | if (err) | |
e9be9d5e | 1026 | goto out_dput; |
e9be9d5e MS |
1027 | |
1028 | if (cleanup_whiteout) | |
1029 | ovl_cleanup(old_upperdir->d_inode, newdentry); | |
1030 | ||
1031 | ovl_dentry_version_inc(old->d_parent); | |
1032 | ovl_dentry_version_inc(new->d_parent); | |
1033 | ||
1034 | out_dput: | |
1035 | dput(newdentry); | |
11f37104 MS |
1036 | out_dput_old: |
1037 | dput(olddentry); | |
e9be9d5e MS |
1038 | out_unlock: |
1039 | unlock_rename(new_upperdir, old_upperdir); | |
1040 | out_revert_creds: | |
1175b6b8 | 1041 | revert_creds(old_cred); |
e9be9d5e MS |
1042 | out_drop_write: |
1043 | ovl_drop_write(old); | |
1044 | out: | |
1045 | dput(opaquedir); | |
1046 | return err; | |
1047 | } | |
1048 | ||
1049 | const struct inode_operations ovl_dir_inode_operations = { | |
1050 | .lookup = ovl_lookup, | |
1051 | .mkdir = ovl_mkdir, | |
1052 | .symlink = ovl_symlink, | |
1053 | .unlink = ovl_unlink, | |
1054 | .rmdir = ovl_rmdir, | |
6c02cb59 | 1055 | .rename = ovl_rename, |
e9be9d5e MS |
1056 | .link = ovl_link, |
1057 | .setattr = ovl_setattr, | |
1058 | .create = ovl_create, | |
1059 | .mknod = ovl_mknod, | |
1060 | .permission = ovl_permission, | |
1061 | .getattr = ovl_dir_getattr, | |
e9be9d5e | 1062 | .listxattr = ovl_listxattr, |
39a25b2b | 1063 | .get_acl = ovl_get_acl, |
d719e8f2 | 1064 | .update_time = ovl_update_time, |
e9be9d5e | 1065 | }; |