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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 | ||
3d27573c | 44 | struct dentry *ovl_lookup_temp(struct dentry *workdir) |
e9be9d5e MS |
45 | { |
46 | struct dentry *temp; | |
47 | char name[20]; | |
6a45b362 | 48 | static atomic_t temp_id = ATOMIC_INIT(0); |
e9be9d5e | 49 | |
6a45b362 RW |
50 | /* counter is allowed to wrap, since temp dentries are ephemeral */ |
51 | snprintf(name, sizeof(name), "#%x", atomic_inc_return(&temp_id)); | |
e9be9d5e MS |
52 | |
53 | temp = lookup_one_len(name, workdir, strlen(name)); | |
54 | if (!IS_ERR(temp) && temp->d_inode) { | |
55 | pr_err("overlayfs: workdir/%s already exists\n", name); | |
56 | dput(temp); | |
57 | temp = ERR_PTR(-EIO); | |
58 | } | |
59 | ||
60 | return temp; | |
61 | } | |
62 | ||
63 | /* caller holds i_mutex on workdir */ | |
64 | static struct dentry *ovl_whiteout(struct dentry *workdir, | |
65 | struct dentry *dentry) | |
66 | { | |
67 | int err; | |
68 | struct dentry *whiteout; | |
69 | struct inode *wdir = workdir->d_inode; | |
70 | ||
3d27573c | 71 | whiteout = ovl_lookup_temp(workdir); |
e9be9d5e MS |
72 | if (IS_ERR(whiteout)) |
73 | return whiteout; | |
74 | ||
75 | err = ovl_do_whiteout(wdir, whiteout); | |
76 | if (err) { | |
77 | dput(whiteout); | |
78 | whiteout = ERR_PTR(err); | |
79 | } | |
80 | ||
81 | return whiteout; | |
82 | } | |
83 | ||
84 | int ovl_create_real(struct inode *dir, struct dentry *newdentry, | |
32a3d848 | 85 | struct cattr *attr, struct dentry *hardlink, bool debug) |
e9be9d5e MS |
86 | { |
87 | int err; | |
88 | ||
89 | if (newdentry->d_inode) | |
90 | return -ESTALE; | |
91 | ||
92 | if (hardlink) { | |
93 | err = ovl_do_link(hardlink, dir, newdentry, debug); | |
94 | } else { | |
32a3d848 | 95 | switch (attr->mode & S_IFMT) { |
e9be9d5e | 96 | case S_IFREG: |
32a3d848 | 97 | err = ovl_do_create(dir, newdentry, attr->mode, debug); |
e9be9d5e MS |
98 | break; |
99 | ||
100 | case S_IFDIR: | |
32a3d848 | 101 | err = ovl_do_mkdir(dir, newdentry, attr->mode, debug); |
e9be9d5e MS |
102 | break; |
103 | ||
104 | case S_IFCHR: | |
105 | case S_IFBLK: | |
106 | case S_IFIFO: | |
107 | case S_IFSOCK: | |
108 | err = ovl_do_mknod(dir, newdentry, | |
32a3d848 | 109 | attr->mode, attr->rdev, debug); |
e9be9d5e MS |
110 | break; |
111 | ||
112 | case S_IFLNK: | |
32a3d848 | 113 | err = ovl_do_symlink(dir, newdentry, attr->link, debug); |
e9be9d5e MS |
114 | break; |
115 | ||
116 | default: | |
117 | err = -EPERM; | |
118 | } | |
119 | } | |
120 | if (!err && WARN_ON(!newdentry->d_inode)) { | |
121 | /* | |
122 | * Not quite sure if non-instantiated dentry is legal or not. | |
123 | * VFS doesn't seem to care so check and warn here. | |
124 | */ | |
125 | err = -ENOENT; | |
126 | } | |
127 | return err; | |
128 | } | |
129 | ||
21a22878 AG |
130 | static int ovl_set_opaque_xerr(struct dentry *dentry, struct dentry *upper, |
131 | int xerr) | |
e9be9d5e | 132 | { |
5cf5b477 MS |
133 | int err; |
134 | ||
21a22878 | 135 | err = ovl_check_setxattr(dentry, upper, OVL_XATTR_OPAQUE, "y", 1, xerr); |
5cf5b477 MS |
136 | if (!err) |
137 | ovl_dentry_set_opaque(dentry); | |
138 | ||
139 | return err; | |
e9be9d5e MS |
140 | } |
141 | ||
21a22878 AG |
142 | static int ovl_set_opaque(struct dentry *dentry, struct dentry *upperdentry) |
143 | { | |
144 | /* | |
145 | * Fail with -EIO when trying to create opaque dir and upper doesn't | |
146 | * support xattrs. ovl_rename() calls ovl_set_opaque_xerr(-EXDEV) to | |
147 | * return a specific error for noxattr case. | |
148 | */ | |
149 | return ovl_set_opaque_xerr(dentry, upperdentry, -EIO); | |
150 | } | |
151 | ||
72e48481 VG |
152 | /* Common operations required to be done after creation of file on upper */ |
153 | static void ovl_instantiate(struct dentry *dentry, struct inode *inode, | |
51f7e52d | 154 | struct dentry *newdentry, bool hardlink) |
72e48481 VG |
155 | { |
156 | ovl_dentry_version_inc(dentry->d_parent); | |
157 | ovl_dentry_update(dentry, newdentry); | |
51f7e52d MS |
158 | if (!hardlink) { |
159 | ovl_inode_update(inode, d_inode(newdentry)); | |
160 | ovl_copyattr(newdentry->d_inode, inode); | |
161 | } else { | |
162 | WARN_ON(ovl_inode_real(inode, NULL) != d_inode(newdentry)); | |
163 | inc_nlink(inode); | |
164 | } | |
72e48481 | 165 | d_instantiate(dentry, inode); |
5b6c9053 AG |
166 | /* Force lookup of new upper hardlink to find its lower */ |
167 | if (hardlink) | |
168 | d_drop(dentry); | |
72e48481 VG |
169 | } |
170 | ||
97c684cc AG |
171 | static bool ovl_type_merge(struct dentry *dentry) |
172 | { | |
173 | return OVL_TYPE_MERGE(ovl_path_type(dentry)); | |
174 | } | |
175 | ||
ee1d6d37 AG |
176 | static bool ovl_type_origin(struct dentry *dentry) |
177 | { | |
178 | return OVL_TYPE_ORIGIN(ovl_path_type(dentry)); | |
179 | } | |
180 | ||
e9be9d5e | 181 | static int ovl_create_upper(struct dentry *dentry, struct inode *inode, |
32a3d848 | 182 | struct cattr *attr, struct dentry *hardlink) |
e9be9d5e MS |
183 | { |
184 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
185 | struct inode *udir = upperdir->d_inode; | |
186 | struct dentry *newdentry; | |
187 | int err; | |
188 | ||
38b25697 | 189 | if (!hardlink && !IS_POSIXACL(udir)) |
32a3d848 | 190 | attr->mode &= ~current_umask(); |
38b25697 | 191 | |
5955102c | 192 | inode_lock_nested(udir, I_MUTEX_PARENT); |
e9be9d5e MS |
193 | newdentry = lookup_one_len(dentry->d_name.name, upperdir, |
194 | dentry->d_name.len); | |
195 | err = PTR_ERR(newdentry); | |
196 | if (IS_ERR(newdentry)) | |
197 | goto out_unlock; | |
32a3d848 | 198 | err = ovl_create_real(udir, newdentry, attr, hardlink, false); |
e9be9d5e MS |
199 | if (err) |
200 | goto out_dput; | |
201 | ||
4a99f3c8 | 202 | if (ovl_type_merge(dentry->d_parent) && d_is_dir(newdentry)) { |
97c684cc AG |
203 | /* Setting opaque here is just an optimization, allow to fail */ |
204 | ovl_set_opaque(dentry, newdentry); | |
205 | } | |
206 | ||
51f7e52d | 207 | ovl_instantiate(dentry, inode, newdentry, !!hardlink); |
e9be9d5e MS |
208 | newdentry = NULL; |
209 | out_dput: | |
210 | dput(newdentry); | |
211 | out_unlock: | |
5955102c | 212 | inode_unlock(udir); |
e9be9d5e MS |
213 | return err; |
214 | } | |
215 | ||
216 | static int ovl_lock_rename_workdir(struct dentry *workdir, | |
217 | struct dentry *upperdir) | |
218 | { | |
219 | /* Workdir should not be the same as upperdir */ | |
220 | if (workdir == upperdir) | |
221 | goto err; | |
222 | ||
223 | /* Workdir should not be subdir of upperdir and vice versa */ | |
224 | if (lock_rename(workdir, upperdir) != NULL) | |
225 | goto err_unlock; | |
226 | ||
227 | return 0; | |
228 | ||
229 | err_unlock: | |
230 | unlock_rename(workdir, upperdir); | |
231 | err: | |
232 | pr_err("overlayfs: failed to lock workdir+upperdir\n"); | |
233 | return -EIO; | |
234 | } | |
235 | ||
236 | static struct dentry *ovl_clear_empty(struct dentry *dentry, | |
237 | struct list_head *list) | |
238 | { | |
239 | struct dentry *workdir = ovl_workdir(dentry); | |
240 | struct inode *wdir = workdir->d_inode; | |
241 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
242 | struct inode *udir = upperdir->d_inode; | |
243 | struct path upperpath; | |
244 | struct dentry *upper; | |
245 | struct dentry *opaquedir; | |
246 | struct kstat stat; | |
247 | int err; | |
248 | ||
cc6f67bc MS |
249 | if (WARN_ON(!workdir)) |
250 | return ERR_PTR(-EROFS); | |
251 | ||
e9be9d5e MS |
252 | err = ovl_lock_rename_workdir(workdir, upperdir); |
253 | if (err) | |
254 | goto out; | |
255 | ||
256 | ovl_path_upper(dentry, &upperpath); | |
a528d35e DH |
257 | err = vfs_getattr(&upperpath, &stat, |
258 | STATX_BASIC_STATS, AT_STATX_SYNC_AS_STAT); | |
e9be9d5e MS |
259 | if (err) |
260 | goto out_unlock; | |
261 | ||
262 | err = -ESTALE; | |
263 | if (!S_ISDIR(stat.mode)) | |
264 | goto out_unlock; | |
265 | upper = upperpath.dentry; | |
266 | if (upper->d_parent->d_inode != udir) | |
267 | goto out_unlock; | |
268 | ||
3d27573c | 269 | opaquedir = ovl_lookup_temp(workdir); |
e9be9d5e MS |
270 | err = PTR_ERR(opaquedir); |
271 | if (IS_ERR(opaquedir)) | |
272 | goto out_unlock; | |
273 | ||
32a3d848 AV |
274 | err = ovl_create_real(wdir, opaquedir, |
275 | &(struct cattr){.mode = stat.mode}, NULL, true); | |
e9be9d5e MS |
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 | 374 | static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode, |
32a3d848 | 375 | struct cattr *cattr, |
e9be9d5e MS |
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, | |
32a3d848 | 392 | &cattr->mode, &default_acl, &acl); |
38b25697 MS |
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 | ||
3d27573c | 401 | newdentry = ovl_lookup_temp(workdir); |
e9be9d5e MS |
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 | ||
32a3d848 | 412 | err = ovl_create_real(wdir, newdentry, cattr, hardlink, true); |
e9be9d5e MS |
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 | 419 | if (!hardlink && |
32a3d848 AV |
420 | !S_ISLNK(cattr->mode) && |
421 | newdentry->d_inode->i_mode != cattr->mode) { | |
bb0d2b8a MS |
422 | struct iattr attr = { |
423 | .ia_valid = ATTR_MODE, | |
32a3d848 | 424 | .ia_mode = cattr->mode, |
bb0d2b8a MS |
425 | }; |
426 | inode_lock(newdentry->d_inode); | |
427 | err = notify_change(newdentry, &attr, NULL); | |
428 | inode_unlock(newdentry->d_inode); | |
429 | if (err) | |
430 | goto out_cleanup; | |
431 | } | |
38b25697 MS |
432 | if (!hardlink) { |
433 | err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_ACCESS, | |
434 | acl); | |
435 | if (err) | |
436 | goto out_cleanup; | |
437 | ||
438 | err = ovl_set_upper_acl(newdentry, XATTR_NAME_POSIX_ACL_DEFAULT, | |
439 | default_acl); | |
440 | if (err) | |
441 | goto out_cleanup; | |
442 | } | |
bb0d2b8a | 443 | |
32a3d848 | 444 | if (!hardlink && S_ISDIR(cattr->mode)) { |
5cf5b477 | 445 | err = ovl_set_opaque(dentry, newdentry); |
e9be9d5e MS |
446 | if (err) |
447 | goto out_cleanup; | |
448 | ||
449 | err = ovl_do_rename(wdir, newdentry, udir, upper, | |
450 | RENAME_EXCHANGE); | |
451 | if (err) | |
452 | goto out_cleanup; | |
453 | ||
454 | ovl_cleanup(wdir, upper); | |
455 | } else { | |
456 | err = ovl_do_rename(wdir, newdentry, udir, upper, 0); | |
457 | if (err) | |
458 | goto out_cleanup; | |
459 | } | |
51f7e52d | 460 | ovl_instantiate(dentry, inode, newdentry, !!hardlink); |
e9be9d5e MS |
461 | newdentry = NULL; |
462 | out_dput2: | |
463 | dput(upper); | |
464 | out_dput: | |
465 | dput(newdentry); | |
466 | out_unlock: | |
467 | unlock_rename(workdir, upperdir); | |
468 | out: | |
38b25697 MS |
469 | if (!hardlink) { |
470 | posix_acl_release(acl); | |
471 | posix_acl_release(default_acl); | |
472 | } | |
e9be9d5e MS |
473 | return err; |
474 | ||
475 | out_cleanup: | |
476 | ovl_cleanup(wdir, newdentry); | |
477 | goto out_dput2; | |
478 | } | |
479 | ||
51f7e52d | 480 | static int ovl_create_or_link(struct dentry *dentry, struct inode *inode, |
32a3d848 | 481 | struct cattr *attr, 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, | |
32a3d848 | 499 | attr->mode, &dentry->d_name, old_cred, |
2602625b VG |
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)) |
32a3d848 | 510 | err = ovl_create_upper(dentry, inode, attr, |
1175b6b8 VG |
511 | hardlink); |
512 | else | |
32a3d848 AV |
513 | err = ovl_create_over_whiteout(dentry, inode, attr, |
514 | 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 | 532 | struct inode *inode; |
32a3d848 | 533 | struct cattr attr = { |
51f7e52d | 534 | .rdev = rdev, |
32a3d848 | 535 | .link = link, |
51f7e52d | 536 | }; |
e9be9d5e MS |
537 | |
538 | err = ovl_want_write(dentry); | |
51f7e52d MS |
539 | if (err) |
540 | goto out; | |
541 | ||
542 | err = -ENOMEM; | |
ca4c8a3a | 543 | inode = ovl_new_inode(dentry->d_sb, mode, rdev); |
51f7e52d MS |
544 | if (!inode) |
545 | goto out_drop_write; | |
546 | ||
547 | inode_init_owner(inode, dentry->d_parent->d_inode, mode); | |
32a3d848 | 548 | attr.mode = inode->i_mode; |
51f7e52d | 549 | |
32a3d848 | 550 | err = ovl_create_or_link(dentry, inode, &attr, NULL); |
51f7e52d MS |
551 | if (err) |
552 | iput(inode); | |
e9be9d5e | 553 | |
51f7e52d MS |
554 | out_drop_write: |
555 | ovl_drop_write(dentry); | |
556 | out: | |
e9be9d5e MS |
557 | return err; |
558 | } | |
559 | ||
560 | static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode, | |
561 | bool excl) | |
562 | { | |
563 | return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL); | |
564 | } | |
565 | ||
566 | static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) | |
567 | { | |
568 | return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL); | |
569 | } | |
570 | ||
571 | static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, | |
572 | dev_t rdev) | |
573 | { | |
574 | /* Don't allow creation of "whiteout" on overlay */ | |
575 | if (S_ISCHR(mode) && rdev == WHITEOUT_DEV) | |
576 | return -EPERM; | |
577 | ||
578 | return ovl_create_object(dentry, mode, rdev, NULL); | |
579 | } | |
580 | ||
581 | static int ovl_symlink(struct inode *dir, struct dentry *dentry, | |
582 | const char *link) | |
583 | { | |
584 | return ovl_create_object(dentry, S_IFLNK, 0, link); | |
585 | } | |
586 | ||
587 | static int ovl_link(struct dentry *old, struct inode *newdir, | |
588 | struct dentry *new) | |
589 | { | |
590 | int err; | |
51f7e52d | 591 | struct inode *inode; |
e9be9d5e MS |
592 | |
593 | err = ovl_want_write(old); | |
594 | if (err) | |
595 | goto out; | |
596 | ||
597 | err = ovl_copy_up(old); | |
598 | if (err) | |
599 | goto out_drop_write; | |
600 | ||
51f7e52d MS |
601 | inode = d_inode(old); |
602 | ihold(inode); | |
603 | ||
32a3d848 | 604 | err = ovl_create_or_link(new, inode, NULL, ovl_dentry_upper(old)); |
51f7e52d MS |
605 | if (err) |
606 | iput(inode); | |
e9be9d5e MS |
607 | |
608 | out_drop_write: | |
609 | ovl_drop_write(old); | |
610 | out: | |
611 | return err; | |
612 | } | |
613 | ||
a105d685 | 614 | static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir) |
e9be9d5e MS |
615 | { |
616 | struct dentry *workdir = ovl_workdir(dentry); | |
617 | struct inode *wdir = workdir->d_inode; | |
618 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
619 | struct inode *udir = upperdir->d_inode; | |
620 | struct dentry *whiteout; | |
621 | struct dentry *upper; | |
622 | struct dentry *opaquedir = NULL; | |
623 | int err; | |
cfc9fde0 | 624 | int flags = 0; |
e9be9d5e | 625 | |
cc6f67bc MS |
626 | if (WARN_ON(!workdir)) |
627 | return -EROFS; | |
628 | ||
d377c5eb | 629 | if (is_dir) { |
30c17ebf MS |
630 | opaquedir = ovl_check_empty_and_clear(dentry); |
631 | err = PTR_ERR(opaquedir); | |
632 | if (IS_ERR(opaquedir)) | |
633 | goto out; | |
e9be9d5e MS |
634 | } |
635 | ||
636 | err = ovl_lock_rename_workdir(workdir, upperdir); | |
637 | if (err) | |
638 | goto out_dput; | |
639 | ||
cfc9fde0 MP |
640 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
641 | dentry->d_name.len); | |
642 | err = PTR_ERR(upper); | |
643 | if (IS_ERR(upper)) | |
e9be9d5e MS |
644 | goto out_unlock; |
645 | ||
cfc9fde0 MP |
646 | err = -ESTALE; |
647 | if ((opaquedir && upper != opaquedir) || | |
648 | (!opaquedir && ovl_dentry_upper(dentry) && | |
649 | upper != ovl_dentry_upper(dentry))) { | |
650 | goto out_dput_upper; | |
651 | } | |
e9be9d5e | 652 | |
cfc9fde0 MP |
653 | whiteout = ovl_whiteout(workdir, dentry); |
654 | err = PTR_ERR(whiteout); | |
655 | if (IS_ERR(whiteout)) | |
656 | goto out_dput_upper; | |
e9be9d5e | 657 | |
cfc9fde0 MP |
658 | if (d_is_dir(upper)) |
659 | flags = RENAME_EXCHANGE; | |
e9be9d5e | 660 | |
cfc9fde0 MP |
661 | err = ovl_do_rename(wdir, whiteout, udir, upper, flags); |
662 | if (err) | |
663 | goto kill_whiteout; | |
664 | if (flags) | |
665 | ovl_cleanup(wdir, upper); | |
e9be9d5e | 666 | |
e9be9d5e MS |
667 | ovl_dentry_version_inc(dentry->d_parent); |
668 | out_d_drop: | |
669 | d_drop(dentry); | |
670 | dput(whiteout); | |
cfc9fde0 MP |
671 | out_dput_upper: |
672 | dput(upper); | |
e9be9d5e MS |
673 | out_unlock: |
674 | unlock_rename(workdir, upperdir); | |
675 | out_dput: | |
676 | dput(opaquedir); | |
677 | out: | |
678 | return err; | |
679 | ||
680 | kill_whiteout: | |
681 | ovl_cleanup(wdir, whiteout); | |
682 | goto out_d_drop; | |
683 | } | |
684 | ||
685 | static int ovl_remove_upper(struct dentry *dentry, bool is_dir) | |
686 | { | |
687 | struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent); | |
688 | struct inode *dir = upperdir->d_inode; | |
11f37104 | 689 | struct dentry *upper; |
d1595119 | 690 | struct dentry *opaquedir = NULL; |
e9be9d5e MS |
691 | int err; |
692 | ||
d1595119 AG |
693 | /* Redirect dir can be !ovl_lower_positive && OVL_TYPE_MERGE */ |
694 | if (is_dir && ovl_dentry_get_redirect(dentry)) { | |
695 | opaquedir = ovl_check_empty_and_clear(dentry); | |
696 | err = PTR_ERR(opaquedir); | |
697 | if (IS_ERR(opaquedir)) | |
698 | goto out; | |
699 | } | |
700 | ||
5955102c | 701 | inode_lock_nested(dir, I_MUTEX_PARENT); |
11f37104 MS |
702 | upper = lookup_one_len(dentry->d_name.name, upperdir, |
703 | dentry->d_name.len); | |
704 | err = PTR_ERR(upper); | |
705 | if (IS_ERR(upper)) | |
706 | goto out_unlock; | |
707 | ||
e9be9d5e | 708 | err = -ESTALE; |
d1595119 AG |
709 | if ((opaquedir && upper != opaquedir) || |
710 | (!opaquedir && upper != ovl_dentry_upper(dentry))) | |
711 | goto out_dput_upper; | |
712 | ||
713 | if (is_dir) | |
714 | err = vfs_rmdir(dir, upper); | |
715 | else | |
716 | err = vfs_unlink(dir, upper, NULL); | |
717 | ovl_dentry_version_inc(dentry->d_parent); | |
e9be9d5e MS |
718 | |
719 | /* | |
720 | * Keeping this dentry hashed would mean having to release | |
721 | * upperpath/lowerpath, which could only be done if we are the | |
722 | * sole user of this dentry. Too tricky... Just unhash for | |
723 | * now. | |
724 | */ | |
ce9113bb RW |
725 | if (!err) |
726 | d_drop(dentry); | |
d1595119 AG |
727 | out_dput_upper: |
728 | dput(upper); | |
11f37104 | 729 | out_unlock: |
5955102c | 730 | inode_unlock(dir); |
d1595119 AG |
731 | dput(opaquedir); |
732 | out: | |
e9be9d5e MS |
733 | return err; |
734 | } | |
735 | ||
e9be9d5e MS |
736 | static int ovl_do_remove(struct dentry *dentry, bool is_dir) |
737 | { | |
738 | enum ovl_path_type type; | |
739 | int err; | |
1175b6b8 VG |
740 | const struct cred *old_cred; |
741 | ||
e9be9d5e MS |
742 | err = ovl_want_write(dentry); |
743 | if (err) | |
744 | goto out; | |
745 | ||
746 | err = ovl_copy_up(dentry->d_parent); | |
747 | if (err) | |
748 | goto out_drop_write; | |
749 | ||
750 | type = ovl_path_type(dentry); | |
e9be9d5e | 751 | |
1175b6b8 | 752 | old_cred = ovl_override_creds(dentry->d_sb); |
2aff4534 | 753 | if (!ovl_lower_positive(dentry)) |
1175b6b8 VG |
754 | err = ovl_remove_upper(dentry, is_dir); |
755 | else | |
a105d685 | 756 | err = ovl_remove_and_whiteout(dentry, is_dir); |
1175b6b8 | 757 | revert_creds(old_cred); |
dbc816d0 MS |
758 | if (!err) { |
759 | if (is_dir) | |
760 | clear_nlink(dentry->d_inode); | |
761 | else | |
762 | drop_nlink(dentry->d_inode); | |
763 | } | |
e9be9d5e MS |
764 | out_drop_write: |
765 | ovl_drop_write(dentry); | |
766 | out: | |
767 | return err; | |
768 | } | |
769 | ||
770 | static int ovl_unlink(struct inode *dir, struct dentry *dentry) | |
771 | { | |
772 | return ovl_do_remove(dentry, false); | |
773 | } | |
774 | ||
775 | static int ovl_rmdir(struct inode *dir, struct dentry *dentry) | |
776 | { | |
777 | return ovl_do_remove(dentry, true); | |
778 | } | |
779 | ||
370e55ac MS |
780 | static bool ovl_type_merge_or_lower(struct dentry *dentry) |
781 | { | |
782 | enum ovl_path_type type = ovl_path_type(dentry); | |
783 | ||
784 | return OVL_TYPE_MERGE(type) || !OVL_TYPE_UPPER(type); | |
785 | } | |
786 | ||
a6c60655 MS |
787 | static bool ovl_can_move(struct dentry *dentry) |
788 | { | |
789 | return ovl_redirect_dir(dentry->d_sb) || | |
790 | !d_is_dir(dentry) || !ovl_type_merge_or_lower(dentry); | |
791 | } | |
792 | ||
a6c60655 MS |
793 | static char *ovl_get_redirect(struct dentry *dentry, bool samedir) |
794 | { | |
795 | char *buf, *ret; | |
796 | struct dentry *d, *tmp; | |
3ea22a71 | 797 | int buflen = ovl_redirect_max + 1; |
a6c60655 MS |
798 | |
799 | if (samedir) { | |
800 | ret = kstrndup(dentry->d_name.name, dentry->d_name.len, | |
801 | GFP_KERNEL); | |
802 | goto out; | |
803 | } | |
804 | ||
805 | buf = ret = kmalloc(buflen, GFP_TEMPORARY); | |
806 | if (!buf) | |
807 | goto out; | |
808 | ||
809 | buflen--; | |
810 | buf[buflen] = '\0'; | |
811 | for (d = dget(dentry); !IS_ROOT(d);) { | |
812 | const char *name; | |
813 | int thislen; | |
814 | ||
815 | spin_lock(&d->d_lock); | |
816 | name = ovl_dentry_get_redirect(d); | |
817 | if (name) { | |
818 | thislen = strlen(name); | |
819 | } else { | |
820 | name = d->d_name.name; | |
821 | thislen = d->d_name.len; | |
822 | } | |
823 | ||
824 | /* If path is too long, fall back to userspace move */ | |
825 | if (thislen + (name[0] != '/') > buflen) { | |
826 | ret = ERR_PTR(-EXDEV); | |
827 | spin_unlock(&d->d_lock); | |
828 | goto out_put; | |
829 | } | |
830 | ||
831 | buflen -= thislen; | |
832 | memcpy(&buf[buflen], name, thislen); | |
833 | tmp = dget_dlock(d->d_parent); | |
834 | spin_unlock(&d->d_lock); | |
835 | ||
836 | dput(d); | |
837 | d = tmp; | |
838 | ||
839 | /* Absolute redirect: finished */ | |
840 | if (buf[buflen] == '/') | |
841 | break; | |
842 | buflen--; | |
843 | buf[buflen] = '/'; | |
844 | } | |
845 | ret = kstrdup(&buf[buflen], GFP_KERNEL); | |
846 | out_put: | |
847 | dput(d); | |
848 | kfree(buf); | |
849 | out: | |
850 | return ret ? ret : ERR_PTR(-ENOMEM); | |
851 | } | |
852 | ||
853 | static int ovl_set_redirect(struct dentry *dentry, bool samedir) | |
854 | { | |
855 | int err; | |
856 | const char *redirect = ovl_dentry_get_redirect(dentry); | |
857 | ||
858 | if (redirect && (samedir || redirect[0] == '/')) | |
859 | return 0; | |
860 | ||
861 | redirect = ovl_get_redirect(dentry, samedir); | |
862 | if (IS_ERR(redirect)) | |
863 | return PTR_ERR(redirect); | |
864 | ||
21a22878 AG |
865 | err = ovl_check_setxattr(dentry, ovl_dentry_upper(dentry), |
866 | OVL_XATTR_REDIRECT, | |
867 | redirect, strlen(redirect), -EXDEV); | |
a6c60655 MS |
868 | if (!err) { |
869 | spin_lock(&dentry->d_lock); | |
870 | ovl_dentry_set_redirect(dentry, redirect); | |
871 | spin_unlock(&dentry->d_lock); | |
872 | } else { | |
873 | kfree(redirect); | |
21a22878 | 874 | pr_warn_ratelimited("overlay: failed to set redirect (%i)\n", err); |
a6c60655 MS |
875 | /* Fall back to userspace copy-up */ |
876 | err = -EXDEV; | |
877 | } | |
878 | return err; | |
879 | } | |
880 | ||
6c02cb59 MS |
881 | static int ovl_rename(struct inode *olddir, struct dentry *old, |
882 | struct inode *newdir, struct dentry *new, | |
883 | unsigned int flags) | |
e9be9d5e MS |
884 | { |
885 | int err; | |
e9be9d5e MS |
886 | struct dentry *old_upperdir; |
887 | struct dentry *new_upperdir; | |
888 | struct dentry *olddentry; | |
889 | struct dentry *newdentry; | |
890 | struct dentry *trap; | |
891 | bool old_opaque; | |
892 | bool new_opaque; | |
e9be9d5e MS |
893 | bool cleanup_whiteout = false; |
894 | bool overwrite = !(flags & RENAME_EXCHANGE); | |
e36cb0b8 | 895 | bool is_dir = d_is_dir(old); |
370e55ac | 896 | bool new_is_dir = d_is_dir(new); |
a6c60655 | 897 | bool samedir = olddir == newdir; |
e9be9d5e MS |
898 | struct dentry *opaquedir = NULL; |
899 | const struct cred *old_cred = NULL; | |
e9be9d5e MS |
900 | |
901 | err = -EINVAL; | |
902 | if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE)) | |
903 | goto out; | |
904 | ||
905 | flags &= ~RENAME_NOREPLACE; | |
906 | ||
e9be9d5e | 907 | /* Don't copy up directory trees */ |
e9be9d5e | 908 | err = -EXDEV; |
a6c60655 | 909 | if (!ovl_can_move(old)) |
370e55ac | 910 | goto out; |
a6c60655 | 911 | if (!overwrite && !ovl_can_move(new)) |
e9be9d5e | 912 | goto out; |
e9be9d5e MS |
913 | |
914 | err = ovl_want_write(old); | |
915 | if (err) | |
916 | goto out; | |
917 | ||
918 | err = ovl_copy_up(old); | |
919 | if (err) | |
920 | goto out_drop_write; | |
921 | ||
922 | err = ovl_copy_up(new->d_parent); | |
923 | if (err) | |
924 | goto out_drop_write; | |
925 | if (!overwrite) { | |
926 | err = ovl_copy_up(new); | |
927 | if (err) | |
928 | goto out_drop_write; | |
929 | } | |
930 | ||
1175b6b8 | 931 | old_cred = ovl_override_creds(old->d_sb); |
e9be9d5e | 932 | |
370e55ac | 933 | if (overwrite && new_is_dir && ovl_type_merge_or_lower(new)) { |
a105d685 | 934 | opaquedir = ovl_check_empty_and_clear(new); |
e9be9d5e MS |
935 | err = PTR_ERR(opaquedir); |
936 | if (IS_ERR(opaquedir)) { | |
937 | opaquedir = NULL; | |
938 | goto out_revert_creds; | |
939 | } | |
940 | } | |
941 | ||
942 | if (overwrite) { | |
2aff4534 | 943 | if (ovl_lower_positive(old)) { |
c412ce49 | 944 | if (!ovl_dentry_is_whiteout(new)) { |
e9be9d5e MS |
945 | /* Whiteout source */ |
946 | flags |= RENAME_WHITEOUT; | |
947 | } else { | |
948 | /* Switch whiteouts */ | |
949 | flags |= RENAME_EXCHANGE; | |
950 | } | |
c412ce49 | 951 | } else if (is_dir && ovl_dentry_is_whiteout(new)) { |
e9be9d5e MS |
952 | flags |= RENAME_EXCHANGE; |
953 | cleanup_whiteout = true; | |
954 | } | |
955 | } | |
956 | ||
957 | old_upperdir = ovl_dentry_upper(old->d_parent); | |
958 | new_upperdir = ovl_dentry_upper(new->d_parent); | |
959 | ||
ee1d6d37 AG |
960 | if (!samedir) { |
961 | /* | |
962 | * When moving a merge dir or non-dir with copy up origin into | |
f3a15685 AG |
963 | * a new parent, we are marking the new parent dir "impure". |
964 | * When ovl_iterate() iterates an "impure" upper dir, it will | |
965 | * lookup the origin inodes of the entries to fill d_ino. | |
ee1d6d37 | 966 | */ |
f3a15685 | 967 | if (ovl_type_origin(old)) { |
ee1d6d37 AG |
968 | err = ovl_set_impure(new->d_parent, new_upperdir); |
969 | if (err) | |
970 | goto out_revert_creds; | |
971 | } | |
f3a15685 | 972 | if (!overwrite && ovl_type_origin(new)) { |
ee1d6d37 AG |
973 | err = ovl_set_impure(old->d_parent, old_upperdir); |
974 | if (err) | |
975 | goto out_revert_creds; | |
976 | } | |
977 | } | |
978 | ||
e9be9d5e MS |
979 | trap = lock_rename(new_upperdir, old_upperdir); |
980 | ||
11f37104 MS |
981 | olddentry = lookup_one_len(old->d_name.name, old_upperdir, |
982 | old->d_name.len); | |
983 | err = PTR_ERR(olddentry); | |
984 | if (IS_ERR(olddentry)) | |
985 | goto out_unlock; | |
986 | ||
987 | err = -ESTALE; | |
988 | if (olddentry != ovl_dentry_upper(old)) | |
989 | goto out_dput_old; | |
990 | ||
991 | newdentry = lookup_one_len(new->d_name.name, new_upperdir, | |
992 | new->d_name.len); | |
993 | err = PTR_ERR(newdentry); | |
994 | if (IS_ERR(newdentry)) | |
995 | goto out_dput_old; | |
996 | ||
3ee23ff1 MS |
997 | old_opaque = ovl_dentry_is_opaque(old); |
998 | new_opaque = ovl_dentry_is_opaque(new); | |
999 | ||
11f37104 MS |
1000 | err = -ESTALE; |
1001 | if (ovl_dentry_upper(new)) { | |
e9be9d5e | 1002 | if (opaquedir) { |
11f37104 MS |
1003 | if (newdentry != opaquedir) |
1004 | goto out_dput; | |
e9be9d5e | 1005 | } else { |
11f37104 MS |
1006 | if (newdentry != ovl_dentry_upper(new)) |
1007 | goto out_dput; | |
e9be9d5e MS |
1008 | } |
1009 | } else { | |
11f37104 MS |
1010 | if (!d_is_negative(newdentry) && |
1011 | (!new_opaque || !ovl_is_whiteout(newdentry))) | |
1012 | goto out_dput; | |
e9be9d5e MS |
1013 | } |
1014 | ||
e9be9d5e MS |
1015 | if (olddentry == trap) |
1016 | goto out_dput; | |
1017 | if (newdentry == trap) | |
1018 | goto out_dput; | |
1019 | ||
804032fa MS |
1020 | if (WARN_ON(olddentry->d_inode == newdentry->d_inode)) |
1021 | goto out_dput; | |
1022 | ||
5cf5b477 | 1023 | err = 0; |
a6c60655 | 1024 | if (is_dir) { |
5cf5b477 | 1025 | if (ovl_type_merge_or_lower(old)) |
a6c60655 | 1026 | err = ovl_set_redirect(old, samedir); |
97c684cc | 1027 | else if (!old_opaque && ovl_type_merge(new->d_parent)) |
21a22878 | 1028 | err = ovl_set_opaque_xerr(old, olddentry, -EXDEV); |
5cf5b477 MS |
1029 | if (err) |
1030 | goto out_dput; | |
e9be9d5e | 1031 | } |
a6c60655 | 1032 | if (!overwrite && new_is_dir) { |
5cf5b477 | 1033 | if (ovl_type_merge_or_lower(new)) |
a6c60655 | 1034 | err = ovl_set_redirect(new, samedir); |
97c684cc | 1035 | else if (!new_opaque && ovl_type_merge(old->d_parent)) |
21a22878 | 1036 | err = ovl_set_opaque_xerr(new, newdentry, -EXDEV); |
5cf5b477 MS |
1037 | if (err) |
1038 | goto out_dput; | |
e9be9d5e MS |
1039 | } |
1040 | ||
3ee23ff1 MS |
1041 | err = ovl_do_rename(old_upperdir->d_inode, olddentry, |
1042 | new_upperdir->d_inode, newdentry, flags); | |
1043 | if (err) | |
e9be9d5e | 1044 | goto out_dput; |
e9be9d5e MS |
1045 | |
1046 | if (cleanup_whiteout) | |
1047 | ovl_cleanup(old_upperdir->d_inode, newdentry); | |
1048 | ||
1049 | ovl_dentry_version_inc(old->d_parent); | |
1050 | ovl_dentry_version_inc(new->d_parent); | |
1051 | ||
1052 | out_dput: | |
1053 | dput(newdentry); | |
11f37104 MS |
1054 | out_dput_old: |
1055 | dput(olddentry); | |
e9be9d5e MS |
1056 | out_unlock: |
1057 | unlock_rename(new_upperdir, old_upperdir); | |
1058 | out_revert_creds: | |
1175b6b8 | 1059 | revert_creds(old_cred); |
e9be9d5e MS |
1060 | out_drop_write: |
1061 | ovl_drop_write(old); | |
1062 | out: | |
1063 | dput(opaquedir); | |
1064 | return err; | |
1065 | } | |
1066 | ||
1067 | const struct inode_operations ovl_dir_inode_operations = { | |
1068 | .lookup = ovl_lookup, | |
1069 | .mkdir = ovl_mkdir, | |
1070 | .symlink = ovl_symlink, | |
1071 | .unlink = ovl_unlink, | |
1072 | .rmdir = ovl_rmdir, | |
6c02cb59 | 1073 | .rename = ovl_rename, |
e9be9d5e MS |
1074 | .link = ovl_link, |
1075 | .setattr = ovl_setattr, | |
1076 | .create = ovl_create, | |
1077 | .mknod = ovl_mknod, | |
1078 | .permission = ovl_permission, | |
5b712091 | 1079 | .getattr = ovl_getattr, |
e9be9d5e | 1080 | .listxattr = ovl_listxattr, |
39a25b2b | 1081 | .get_acl = ovl_get_acl, |
d719e8f2 | 1082 | .update_time = ovl_update_time, |
e9be9d5e | 1083 | }; |