dir.c 20 KB

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  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. #include <linux/fs.h>
  10. #include <linux/namei.h>
  11. #include <linux/xattr.h>
  12. #include <linux/security.h>
  13. #include <linux/cred.h>
  14. #include "overlayfs.h"
  15. void ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
  16. {
  17. int err;
  18. dget(wdentry);
  19. if (d_is_dir(wdentry))
  20. err = ovl_do_rmdir(wdir, wdentry);
  21. else
  22. err = ovl_do_unlink(wdir, wdentry);
  23. dput(wdentry);
  24. if (err) {
  25. pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n",
  26. wdentry, err);
  27. }
  28. }
  29. struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry)
  30. {
  31. struct dentry *temp;
  32. char name[20];
  33. snprintf(name, sizeof(name), "#%lx", (unsigned long) dentry);
  34. temp = lookup_one_len(name, workdir, strlen(name));
  35. if (!IS_ERR(temp) && temp->d_inode) {
  36. pr_err("overlayfs: workdir/%s already exists\n", name);
  37. dput(temp);
  38. temp = ERR_PTR(-EIO);
  39. }
  40. return temp;
  41. }
  42. /* caller holds i_mutex on workdir */
  43. static struct dentry *ovl_whiteout(struct dentry *workdir,
  44. struct dentry *dentry)
  45. {
  46. int err;
  47. struct dentry *whiteout;
  48. struct inode *wdir = workdir->d_inode;
  49. whiteout = ovl_lookup_temp(workdir, dentry);
  50. if (IS_ERR(whiteout))
  51. return whiteout;
  52. err = ovl_do_whiteout(wdir, whiteout);
  53. if (err) {
  54. dput(whiteout);
  55. whiteout = ERR_PTR(err);
  56. }
  57. return whiteout;
  58. }
  59. int ovl_create_real(struct inode *dir, struct dentry *newdentry,
  60. struct kstat *stat, const char *link,
  61. struct dentry *hardlink, bool debug)
  62. {
  63. int err;
  64. if (newdentry->d_inode)
  65. return -ESTALE;
  66. if (hardlink) {
  67. err = ovl_do_link(hardlink, dir, newdentry, debug);
  68. } else {
  69. switch (stat->mode & S_IFMT) {
  70. case S_IFREG:
  71. err = ovl_do_create(dir, newdentry, stat->mode, debug);
  72. break;
  73. case S_IFDIR:
  74. err = ovl_do_mkdir(dir, newdentry, stat->mode, debug);
  75. break;
  76. case S_IFCHR:
  77. case S_IFBLK:
  78. case S_IFIFO:
  79. case S_IFSOCK:
  80. err = ovl_do_mknod(dir, newdentry,
  81. stat->mode, stat->rdev, debug);
  82. break;
  83. case S_IFLNK:
  84. err = ovl_do_symlink(dir, newdentry, link, debug);
  85. break;
  86. default:
  87. err = -EPERM;
  88. }
  89. }
  90. if (!err && WARN_ON(!newdentry->d_inode)) {
  91. /*
  92. * Not quite sure if non-instantiated dentry is legal or not.
  93. * VFS doesn't seem to care so check and warn here.
  94. */
  95. err = -ENOENT;
  96. }
  97. return err;
  98. }
  99. static int ovl_set_opaque(struct dentry *upperdentry)
  100. {
  101. return ovl_do_setxattr(upperdentry, OVL_XATTR_OPAQUE, "y", 1, 0);
  102. }
  103. static void ovl_remove_opaque(struct dentry *upperdentry)
  104. {
  105. int err;
  106. err = ovl_do_removexattr(upperdentry, OVL_XATTR_OPAQUE);
  107. if (err) {
  108. pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n",
  109. upperdentry->d_name.name, err);
  110. }
  111. }
  112. static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
  113. struct kstat *stat)
  114. {
  115. int err;
  116. enum ovl_path_type type;
  117. struct path realpath;
  118. type = ovl_path_real(dentry, &realpath);
  119. err = vfs_getattr(&realpath, stat);
  120. if (err)
  121. return err;
  122. stat->dev = dentry->d_sb->s_dev;
  123. stat->ino = dentry->d_inode->i_ino;
  124. /*
  125. * It's probably not worth it to count subdirs to get the
  126. * correct link count. nlink=1 seems to pacify 'find' and
  127. * other utilities.
  128. */
  129. if (OVL_TYPE_MERGE(type))
  130. stat->nlink = 1;
  131. return 0;
  132. }
  133. static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
  134. struct kstat *stat, const char *link,
  135. struct dentry *hardlink)
  136. {
  137. struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
  138. struct inode *udir = upperdir->d_inode;
  139. struct dentry *newdentry;
  140. int err;
  141. inode_lock_nested(udir, I_MUTEX_PARENT);
  142. newdentry = lookup_one_len(dentry->d_name.name, upperdir,
  143. dentry->d_name.len);
  144. err = PTR_ERR(newdentry);
  145. if (IS_ERR(newdentry))
  146. goto out_unlock;
  147. err = ovl_create_real(udir, newdentry, stat, link, hardlink, false);
  148. if (err)
  149. goto out_dput;
  150. ovl_dentry_version_inc(dentry->d_parent);
  151. ovl_dentry_update(dentry, newdentry);
  152. ovl_copyattr(newdentry->d_inode, inode);
  153. d_instantiate(dentry, inode);
  154. newdentry = NULL;
  155. out_dput:
  156. dput(newdentry);
  157. out_unlock:
  158. inode_unlock(udir);
  159. return err;
  160. }
  161. static int ovl_lock_rename_workdir(struct dentry *workdir,
  162. struct dentry *upperdir)
  163. {
  164. /* Workdir should not be the same as upperdir */
  165. if (workdir == upperdir)
  166. goto err;
  167. /* Workdir should not be subdir of upperdir and vice versa */
  168. if (lock_rename(workdir, upperdir) != NULL)
  169. goto err_unlock;
  170. return 0;
  171. err_unlock:
  172. unlock_rename(workdir, upperdir);
  173. err:
  174. pr_err("overlayfs: failed to lock workdir+upperdir\n");
  175. return -EIO;
  176. }
  177. static struct dentry *ovl_clear_empty(struct dentry *dentry,
  178. struct list_head *list)
  179. {
  180. struct dentry *workdir = ovl_workdir(dentry);
  181. struct inode *wdir = workdir->d_inode;
  182. struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
  183. struct inode *udir = upperdir->d_inode;
  184. struct path upperpath;
  185. struct dentry *upper;
  186. struct dentry *opaquedir;
  187. struct kstat stat;
  188. int err;
  189. if (WARN_ON(!workdir))
  190. return ERR_PTR(-EROFS);
  191. err = ovl_lock_rename_workdir(workdir, upperdir);
  192. if (err)
  193. goto out;
  194. ovl_path_upper(dentry, &upperpath);
  195. err = vfs_getattr(&upperpath, &stat);
  196. if (err)
  197. goto out_unlock;
  198. err = -ESTALE;
  199. if (!S_ISDIR(stat.mode))
  200. goto out_unlock;
  201. upper = upperpath.dentry;
  202. if (upper->d_parent->d_inode != udir)
  203. goto out_unlock;
  204. opaquedir = ovl_lookup_temp(workdir, dentry);
  205. err = PTR_ERR(opaquedir);
  206. if (IS_ERR(opaquedir))
  207. goto out_unlock;
  208. err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true);
  209. if (err)
  210. goto out_dput;
  211. err = ovl_copy_xattr(upper, opaquedir);
  212. if (err)
  213. goto out_cleanup;
  214. err = ovl_set_opaque(opaquedir);
  215. if (err)
  216. goto out_cleanup;
  217. inode_lock(opaquedir->d_inode);
  218. err = ovl_set_attr(opaquedir, &stat);
  219. inode_unlock(opaquedir->d_inode);
  220. if (err)
  221. goto out_cleanup;
  222. err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE);
  223. if (err)
  224. goto out_cleanup;
  225. ovl_cleanup_whiteouts(upper, list);
  226. ovl_cleanup(wdir, upper);
  227. unlock_rename(workdir, upperdir);
  228. /* dentry's upper doesn't match now, get rid of it */
  229. d_drop(dentry);
  230. return opaquedir;
  231. out_cleanup:
  232. ovl_cleanup(wdir, opaquedir);
  233. out_dput:
  234. dput(opaquedir);
  235. out_unlock:
  236. unlock_rename(workdir, upperdir);
  237. out:
  238. return ERR_PTR(err);
  239. }
  240. static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry)
  241. {
  242. int err;
  243. struct dentry *ret = NULL;
  244. LIST_HEAD(list);
  245. err = ovl_check_empty_dir(dentry, &list);
  246. if (err)
  247. ret = ERR_PTR(err);
  248. else {
  249. /*
  250. * If no upperdentry then skip clearing whiteouts.
  251. *
  252. * Can race with copy-up, since we don't hold the upperdir
  253. * mutex. Doesn't matter, since copy-up can't create a
  254. * non-empty directory from an empty one.
  255. */
  256. if (ovl_dentry_upper(dentry))
  257. ret = ovl_clear_empty(dentry, &list);
  258. }
  259. ovl_cache_free(&list);
  260. return ret;
  261. }
  262. static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
  263. struct kstat *stat, const char *link,
  264. struct dentry *hardlink)
  265. {
  266. struct dentry *workdir = ovl_workdir(dentry);
  267. struct inode *wdir = workdir->d_inode;
  268. struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
  269. struct inode *udir = upperdir->d_inode;
  270. struct dentry *upper;
  271. struct dentry *newdentry;
  272. int err;
  273. if (WARN_ON(!workdir))
  274. return -EROFS;
  275. err = ovl_lock_rename_workdir(workdir, upperdir);
  276. if (err)
  277. goto out;
  278. newdentry = ovl_lookup_temp(workdir, dentry);
  279. err = PTR_ERR(newdentry);
  280. if (IS_ERR(newdentry))
  281. goto out_unlock;
  282. upper = lookup_one_len(dentry->d_name.name, upperdir,
  283. dentry->d_name.len);
  284. err = PTR_ERR(upper);
  285. if (IS_ERR(upper))
  286. goto out_dput;
  287. err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true);
  288. if (err)
  289. goto out_dput2;
  290. if (S_ISDIR(stat->mode)) {
  291. err = ovl_set_opaque(newdentry);
  292. if (err)
  293. goto out_cleanup;
  294. err = ovl_do_rename(wdir, newdentry, udir, upper,
  295. RENAME_EXCHANGE);
  296. if (err)
  297. goto out_cleanup;
  298. ovl_cleanup(wdir, upper);
  299. } else {
  300. err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
  301. if (err)
  302. goto out_cleanup;
  303. }
  304. ovl_dentry_version_inc(dentry->d_parent);
  305. ovl_dentry_update(dentry, newdentry);
  306. ovl_copyattr(newdentry->d_inode, inode);
  307. d_instantiate(dentry, inode);
  308. newdentry = NULL;
  309. out_dput2:
  310. dput(upper);
  311. out_dput:
  312. dput(newdentry);
  313. out_unlock:
  314. unlock_rename(workdir, upperdir);
  315. out:
  316. return err;
  317. out_cleanup:
  318. ovl_cleanup(wdir, newdentry);
  319. goto out_dput2;
  320. }
  321. static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev,
  322. const char *link, struct dentry *hardlink)
  323. {
  324. int err;
  325. struct inode *inode;
  326. struct kstat stat = {
  327. .mode = mode,
  328. .rdev = rdev,
  329. };
  330. err = -ENOMEM;
  331. inode = ovl_new_inode(dentry->d_sb, mode, dentry->d_fsdata);
  332. if (!inode)
  333. goto out;
  334. err = ovl_copy_up(dentry->d_parent);
  335. if (err)
  336. goto out_iput;
  337. if (!ovl_dentry_is_opaque(dentry)) {
  338. err = ovl_create_upper(dentry, inode, &stat, link, hardlink);
  339. } else {
  340. const struct cred *old_cred;
  341. old_cred = ovl_override_creds(dentry->d_sb);
  342. err = ovl_create_over_whiteout(dentry, inode, &stat, link,
  343. hardlink);
  344. revert_creds(old_cred);
  345. }
  346. if (!err)
  347. inode = NULL;
  348. out_iput:
  349. iput(inode);
  350. out:
  351. return err;
  352. }
  353. static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
  354. const char *link)
  355. {
  356. int err;
  357. err = ovl_want_write(dentry);
  358. if (!err) {
  359. err = ovl_create_or_link(dentry, mode, rdev, link, NULL);
  360. ovl_drop_write(dentry);
  361. }
  362. return err;
  363. }
  364. static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode,
  365. bool excl)
  366. {
  367. return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
  368. }
  369. static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
  370. {
  371. return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL);
  372. }
  373. static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
  374. dev_t rdev)
  375. {
  376. /* Don't allow creation of "whiteout" on overlay */
  377. if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
  378. return -EPERM;
  379. return ovl_create_object(dentry, mode, rdev, NULL);
  380. }
  381. static int ovl_symlink(struct inode *dir, struct dentry *dentry,
  382. const char *link)
  383. {
  384. return ovl_create_object(dentry, S_IFLNK, 0, link);
  385. }
  386. static int ovl_link(struct dentry *old, struct inode *newdir,
  387. struct dentry *new)
  388. {
  389. int err;
  390. struct dentry *upper;
  391. err = ovl_want_write(old);
  392. if (err)
  393. goto out;
  394. err = ovl_copy_up(old);
  395. if (err)
  396. goto out_drop_write;
  397. upper = ovl_dentry_upper(old);
  398. err = ovl_create_or_link(new, upper->d_inode->i_mode, 0, NULL, upper);
  399. out_drop_write:
  400. ovl_drop_write(old);
  401. out:
  402. return err;
  403. }
  404. static int ovl_remove_and_whiteout(struct dentry *dentry, bool is_dir)
  405. {
  406. struct dentry *workdir = ovl_workdir(dentry);
  407. struct inode *wdir = workdir->d_inode;
  408. struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
  409. struct inode *udir = upperdir->d_inode;
  410. struct dentry *whiteout;
  411. struct dentry *upper;
  412. struct dentry *opaquedir = NULL;
  413. int err;
  414. if (WARN_ON(!workdir))
  415. return -EROFS;
  416. if (is_dir) {
  417. if (OVL_TYPE_MERGE_OR_LOWER(ovl_path_type(dentry))) {
  418. opaquedir = ovl_check_empty_and_clear(dentry);
  419. err = PTR_ERR(opaquedir);
  420. if (IS_ERR(opaquedir))
  421. goto out;
  422. } else {
  423. LIST_HEAD(list);
  424. /*
  425. * When removing an empty opaque directory, then it
  426. * makes no sense to replace it with an exact replica of
  427. * itself. But emptiness still needs to be checked.
  428. */
  429. err = ovl_check_empty_dir(dentry, &list);
  430. ovl_cache_free(&list);
  431. if (err)
  432. goto out;
  433. }
  434. }
  435. err = ovl_lock_rename_workdir(workdir, upperdir);
  436. if (err)
  437. goto out_dput;
  438. whiteout = ovl_whiteout(workdir, dentry);
  439. err = PTR_ERR(whiteout);
  440. if (IS_ERR(whiteout))
  441. goto out_unlock;
  442. upper = ovl_dentry_upper(dentry);
  443. if (!upper) {
  444. upper = lookup_one_len(dentry->d_name.name, upperdir,
  445. dentry->d_name.len);
  446. err = PTR_ERR(upper);
  447. if (IS_ERR(upper))
  448. goto kill_whiteout;
  449. err = ovl_do_rename(wdir, whiteout, udir, upper, 0);
  450. dput(upper);
  451. if (err)
  452. goto kill_whiteout;
  453. } else {
  454. int flags = 0;
  455. if (opaquedir)
  456. upper = opaquedir;
  457. err = -ESTALE;
  458. if (upper->d_parent != upperdir)
  459. goto kill_whiteout;
  460. if (is_dir)
  461. flags |= RENAME_EXCHANGE;
  462. err = ovl_do_rename(wdir, whiteout, udir, upper, flags);
  463. if (err)
  464. goto kill_whiteout;
  465. if (is_dir)
  466. ovl_cleanup(wdir, upper);
  467. }
  468. ovl_dentry_version_inc(dentry->d_parent);
  469. out_d_drop:
  470. d_drop(dentry);
  471. dput(whiteout);
  472. out_unlock:
  473. unlock_rename(workdir, upperdir);
  474. out_dput:
  475. dput(opaquedir);
  476. out:
  477. return err;
  478. kill_whiteout:
  479. ovl_cleanup(wdir, whiteout);
  480. goto out_d_drop;
  481. }
  482. static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
  483. {
  484. struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
  485. struct inode *dir = upperdir->d_inode;
  486. struct dentry *upper;
  487. int err;
  488. inode_lock_nested(dir, I_MUTEX_PARENT);
  489. upper = lookup_one_len(dentry->d_name.name, upperdir,
  490. dentry->d_name.len);
  491. err = PTR_ERR(upper);
  492. if (IS_ERR(upper))
  493. goto out_unlock;
  494. err = -ESTALE;
  495. if (upper == ovl_dentry_upper(dentry)) {
  496. if (is_dir)
  497. err = vfs_rmdir(dir, upper);
  498. else
  499. err = vfs_unlink(dir, upper, NULL);
  500. ovl_dentry_version_inc(dentry->d_parent);
  501. }
  502. dput(upper);
  503. /*
  504. * Keeping this dentry hashed would mean having to release
  505. * upperpath/lowerpath, which could only be done if we are the
  506. * sole user of this dentry. Too tricky... Just unhash for
  507. * now.
  508. */
  509. if (!err)
  510. d_drop(dentry);
  511. out_unlock:
  512. inode_unlock(dir);
  513. return err;
  514. }
  515. static inline int ovl_check_sticky(struct dentry *dentry)
  516. {
  517. struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode;
  518. struct inode *inode = ovl_dentry_real(dentry)->d_inode;
  519. if (check_sticky(dir, inode))
  520. return -EPERM;
  521. return 0;
  522. }
  523. static int ovl_do_remove(struct dentry *dentry, bool is_dir)
  524. {
  525. enum ovl_path_type type;
  526. int err;
  527. err = ovl_check_sticky(dentry);
  528. if (err)
  529. goto out;
  530. err = ovl_want_write(dentry);
  531. if (err)
  532. goto out;
  533. err = ovl_copy_up(dentry->d_parent);
  534. if (err)
  535. goto out_drop_write;
  536. type = ovl_path_type(dentry);
  537. if (OVL_TYPE_PURE_UPPER(type)) {
  538. err = ovl_remove_upper(dentry, is_dir);
  539. } else {
  540. const struct cred *old_cred = ovl_override_creds(dentry->d_sb);
  541. err = ovl_remove_and_whiteout(dentry, is_dir);
  542. revert_creds(old_cred);
  543. }
  544. out_drop_write:
  545. ovl_drop_write(dentry);
  546. out:
  547. return err;
  548. }
  549. static int ovl_unlink(struct inode *dir, struct dentry *dentry)
  550. {
  551. return ovl_do_remove(dentry, false);
  552. }
  553. static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
  554. {
  555. return ovl_do_remove(dentry, true);
  556. }
  557. static int ovl_rename2(struct inode *olddir, struct dentry *old,
  558. struct inode *newdir, struct dentry *new,
  559. unsigned int flags)
  560. {
  561. int err;
  562. enum ovl_path_type old_type;
  563. enum ovl_path_type new_type;
  564. struct dentry *old_upperdir;
  565. struct dentry *new_upperdir;
  566. struct dentry *olddentry;
  567. struct dentry *newdentry;
  568. struct dentry *trap;
  569. bool old_opaque;
  570. bool new_opaque;
  571. bool cleanup_whiteout = false;
  572. bool overwrite = !(flags & RENAME_EXCHANGE);
  573. bool is_dir = d_is_dir(old);
  574. bool new_is_dir = false;
  575. struct dentry *opaquedir = NULL;
  576. const struct cred *old_cred = NULL;
  577. err = -EINVAL;
  578. if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
  579. goto out;
  580. flags &= ~RENAME_NOREPLACE;
  581. err = ovl_check_sticky(old);
  582. if (err)
  583. goto out;
  584. /* Don't copy up directory trees */
  585. old_type = ovl_path_type(old);
  586. err = -EXDEV;
  587. if (OVL_TYPE_MERGE_OR_LOWER(old_type) && is_dir)
  588. goto out;
  589. if (new->d_inode) {
  590. err = ovl_check_sticky(new);
  591. if (err)
  592. goto out;
  593. if (d_is_dir(new))
  594. new_is_dir = true;
  595. new_type = ovl_path_type(new);
  596. err = -EXDEV;
  597. if (!overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir)
  598. goto out;
  599. err = 0;
  600. if (!OVL_TYPE_UPPER(new_type) && !OVL_TYPE_UPPER(old_type)) {
  601. if (ovl_dentry_lower(old)->d_inode ==
  602. ovl_dentry_lower(new)->d_inode)
  603. goto out;
  604. }
  605. if (OVL_TYPE_UPPER(new_type) && OVL_TYPE_UPPER(old_type)) {
  606. if (ovl_dentry_upper(old)->d_inode ==
  607. ovl_dentry_upper(new)->d_inode)
  608. goto out;
  609. }
  610. } else {
  611. if (ovl_dentry_is_opaque(new))
  612. new_type = __OVL_PATH_UPPER;
  613. else
  614. new_type = __OVL_PATH_UPPER | __OVL_PATH_PURE;
  615. }
  616. err = ovl_want_write(old);
  617. if (err)
  618. goto out;
  619. err = ovl_copy_up(old);
  620. if (err)
  621. goto out_drop_write;
  622. err = ovl_copy_up(new->d_parent);
  623. if (err)
  624. goto out_drop_write;
  625. if (!overwrite) {
  626. err = ovl_copy_up(new);
  627. if (err)
  628. goto out_drop_write;
  629. }
  630. old_opaque = !OVL_TYPE_PURE_UPPER(old_type);
  631. new_opaque = !OVL_TYPE_PURE_UPPER(new_type);
  632. if (old_opaque || new_opaque)
  633. old_cred = ovl_override_creds(old->d_sb);
  634. if (overwrite && OVL_TYPE_MERGE_OR_LOWER(new_type) && new_is_dir) {
  635. opaquedir = ovl_check_empty_and_clear(new);
  636. err = PTR_ERR(opaquedir);
  637. if (IS_ERR(opaquedir)) {
  638. opaquedir = NULL;
  639. goto out_revert_creds;
  640. }
  641. }
  642. if (overwrite) {
  643. if (old_opaque) {
  644. if (new->d_inode || !new_opaque) {
  645. /* Whiteout source */
  646. flags |= RENAME_WHITEOUT;
  647. } else {
  648. /* Switch whiteouts */
  649. flags |= RENAME_EXCHANGE;
  650. }
  651. } else if (is_dir && !new->d_inode && new_opaque) {
  652. flags |= RENAME_EXCHANGE;
  653. cleanup_whiteout = true;
  654. }
  655. }
  656. old_upperdir = ovl_dentry_upper(old->d_parent);
  657. new_upperdir = ovl_dentry_upper(new->d_parent);
  658. trap = lock_rename(new_upperdir, old_upperdir);
  659. olddentry = lookup_one_len(old->d_name.name, old_upperdir,
  660. old->d_name.len);
  661. err = PTR_ERR(olddentry);
  662. if (IS_ERR(olddentry))
  663. goto out_unlock;
  664. err = -ESTALE;
  665. if (olddentry != ovl_dentry_upper(old))
  666. goto out_dput_old;
  667. newdentry = lookup_one_len(new->d_name.name, new_upperdir,
  668. new->d_name.len);
  669. err = PTR_ERR(newdentry);
  670. if (IS_ERR(newdentry))
  671. goto out_dput_old;
  672. err = -ESTALE;
  673. if (ovl_dentry_upper(new)) {
  674. if (opaquedir) {
  675. if (newdentry != opaquedir)
  676. goto out_dput;
  677. } else {
  678. if (newdentry != ovl_dentry_upper(new))
  679. goto out_dput;
  680. }
  681. } else {
  682. if (!d_is_negative(newdentry) &&
  683. (!new_opaque || !ovl_is_whiteout(newdentry)))
  684. goto out_dput;
  685. }
  686. if (olddentry == trap)
  687. goto out_dput;
  688. if (newdentry == trap)
  689. goto out_dput;
  690. if (is_dir && !old_opaque && new_opaque) {
  691. err = ovl_set_opaque(olddentry);
  692. if (err)
  693. goto out_dput;
  694. }
  695. if (!overwrite && new_is_dir && old_opaque && !new_opaque) {
  696. err = ovl_set_opaque(newdentry);
  697. if (err)
  698. goto out_dput;
  699. }
  700. if (old_opaque || new_opaque) {
  701. err = ovl_do_rename(old_upperdir->d_inode, olddentry,
  702. new_upperdir->d_inode, newdentry,
  703. flags);
  704. } else {
  705. /* No debug for the plain case */
  706. BUG_ON(flags & ~RENAME_EXCHANGE);
  707. err = vfs_rename(old_upperdir->d_inode, olddentry,
  708. new_upperdir->d_inode, newdentry,
  709. NULL, flags);
  710. }
  711. if (err) {
  712. if (is_dir && !old_opaque && new_opaque)
  713. ovl_remove_opaque(olddentry);
  714. if (!overwrite && new_is_dir && old_opaque && !new_opaque)
  715. ovl_remove_opaque(newdentry);
  716. goto out_dput;
  717. }
  718. if (is_dir && old_opaque && !new_opaque)
  719. ovl_remove_opaque(olddentry);
  720. if (!overwrite && new_is_dir && !old_opaque && new_opaque)
  721. ovl_remove_opaque(newdentry);
  722. /*
  723. * Old dentry now lives in different location. Dentries in
  724. * lowerstack are stale. We cannot drop them here because
  725. * access to them is lockless. This could be only pure upper
  726. * or opaque directory - numlower is zero. Or upper non-dir
  727. * entry - its pureness is tracked by flag opaque.
  728. */
  729. if (old_opaque != new_opaque) {
  730. ovl_dentry_set_opaque(old, new_opaque);
  731. if (!overwrite)
  732. ovl_dentry_set_opaque(new, old_opaque);
  733. }
  734. if (cleanup_whiteout)
  735. ovl_cleanup(old_upperdir->d_inode, newdentry);
  736. ovl_dentry_version_inc(old->d_parent);
  737. ovl_dentry_version_inc(new->d_parent);
  738. out_dput:
  739. dput(newdentry);
  740. out_dput_old:
  741. dput(olddentry);
  742. out_unlock:
  743. unlock_rename(new_upperdir, old_upperdir);
  744. out_revert_creds:
  745. if (old_opaque || new_opaque)
  746. revert_creds(old_cred);
  747. out_drop_write:
  748. ovl_drop_write(old);
  749. out:
  750. dput(opaquedir);
  751. return err;
  752. }
  753. const struct inode_operations ovl_dir_inode_operations = {
  754. .lookup = ovl_lookup,
  755. .mkdir = ovl_mkdir,
  756. .symlink = ovl_symlink,
  757. .unlink = ovl_unlink,
  758. .rmdir = ovl_rmdir,
  759. .rename2 = ovl_rename2,
  760. .link = ovl_link,
  761. .setattr = ovl_setattr,
  762. .create = ovl_create,
  763. .mknod = ovl_mknod,
  764. .permission = ovl_permission,
  765. .getattr = ovl_dir_getattr,
  766. .setxattr = ovl_setxattr,
  767. .getxattr = ovl_getxattr,
  768. .listxattr = ovl_listxattr,
  769. .removexattr = ovl_removexattr,
  770. };