namei.c 9.8 KB

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  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * linux/fs/ext2/namei.c
  4. *
  5. * Rewrite to pagecache. Almost all code had been changed, so blame me
  6. * if the things go wrong. Please, send bug reports to
  7. * [email protected]
  8. *
  9. * Stuff here is basically a glue between the VFS and generic UNIXish
  10. * filesystem that keeps everything in pagecache. All knowledge of the
  11. * directory layout is in fs/ext2/dir.c - it turned out to be easily separatable
  12. * and it's easier to debug that way. In principle we might want to
  13. * generalize that a bit and turn it into a library. Or not.
  14. *
  15. * The only non-static object here is ext2_dir_inode_operations.
  16. *
  17. * TODO: get rid of kmap() use, add readahead.
  18. *
  19. * Copyright (C) 1992, 1993, 1994, 1995
  20. * Remy Card ([email protected])
  21. * Laboratoire MASI - Institut Blaise Pascal
  22. * Universite Pierre et Marie Curie (Paris VI)
  23. *
  24. * from
  25. *
  26. * linux/fs/minix/namei.c
  27. *
  28. * Copyright (C) 1991, 1992 Linus Torvalds
  29. *
  30. * Big-endian to little-endian byte-swapping/bitmaps by
  31. * David S. Miller ([email protected]), 1995
  32. */
  33. #include <linux/pagemap.h>
  34. #include <linux/quotaops.h>
  35. #include "ext2.h"
  36. #include "xattr.h"
  37. #include "acl.h"
  38. static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode)
  39. {
  40. int err = ext2_add_link(dentry, inode);
  41. if (!err) {
  42. d_instantiate_new(dentry, inode);
  43. return 0;
  44. }
  45. inode_dec_link_count(inode);
  46. discard_new_inode(inode);
  47. return err;
  48. }
  49. /*
  50. * Methods themselves.
  51. */
  52. static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags)
  53. {
  54. struct inode * inode;
  55. ino_t ino;
  56. int res;
  57. if (dentry->d_name.len > EXT2_NAME_LEN)
  58. return ERR_PTR(-ENAMETOOLONG);
  59. res = ext2_inode_by_name(dir, &dentry->d_name, &ino);
  60. if (res) {
  61. if (res != -ENOENT)
  62. return ERR_PTR(res);
  63. inode = NULL;
  64. } else {
  65. inode = ext2_iget(dir->i_sb, ino);
  66. if (inode == ERR_PTR(-ESTALE)) {
  67. ext2_error(dir->i_sb, __func__,
  68. "deleted inode referenced: %lu",
  69. (unsigned long) ino);
  70. return ERR_PTR(-EIO);
  71. }
  72. }
  73. return d_splice_alias(inode, dentry);
  74. }
  75. struct dentry *ext2_get_parent(struct dentry *child)
  76. {
  77. ino_t ino;
  78. int res;
  79. res = ext2_inode_by_name(d_inode(child), &dotdot_name, &ino);
  80. if (res)
  81. return ERR_PTR(res);
  82. return d_obtain_alias(ext2_iget(child->d_sb, ino));
  83. }
  84. /*
  85. * By the time this is called, we already have created
  86. * the directory cache entry for the new file, but it
  87. * is so far negative - it has no inode.
  88. *
  89. * If the create succeeds, we fill in the inode information
  90. * with d_instantiate().
  91. */
  92. static int ext2_create (struct user_namespace * mnt_userns,
  93. struct inode * dir, struct dentry * dentry,
  94. umode_t mode, bool excl)
  95. {
  96. struct inode *inode;
  97. int err;
  98. err = dquot_initialize(dir);
  99. if (err)
  100. return err;
  101. inode = ext2_new_inode(dir, mode, &dentry->d_name);
  102. if (IS_ERR(inode))
  103. return PTR_ERR(inode);
  104. ext2_set_file_ops(inode);
  105. mark_inode_dirty(inode);
  106. return ext2_add_nondir(dentry, inode);
  107. }
  108. static int ext2_tmpfile(struct user_namespace *mnt_userns, struct inode *dir,
  109. struct file *file, umode_t mode)
  110. {
  111. struct inode *inode = ext2_new_inode(dir, mode, NULL);
  112. if (IS_ERR(inode))
  113. return PTR_ERR(inode);
  114. ext2_set_file_ops(inode);
  115. mark_inode_dirty(inode);
  116. d_tmpfile(file, inode);
  117. unlock_new_inode(inode);
  118. return finish_open_simple(file, 0);
  119. }
  120. static int ext2_mknod (struct user_namespace * mnt_userns, struct inode * dir,
  121. struct dentry *dentry, umode_t mode, dev_t rdev)
  122. {
  123. struct inode * inode;
  124. int err;
  125. err = dquot_initialize(dir);
  126. if (err)
  127. return err;
  128. inode = ext2_new_inode (dir, mode, &dentry->d_name);
  129. err = PTR_ERR(inode);
  130. if (!IS_ERR(inode)) {
  131. init_special_inode(inode, inode->i_mode, rdev);
  132. inode->i_op = &ext2_special_inode_operations;
  133. mark_inode_dirty(inode);
  134. err = ext2_add_nondir(dentry, inode);
  135. }
  136. return err;
  137. }
  138. static int ext2_symlink (struct user_namespace * mnt_userns, struct inode * dir,
  139. struct dentry * dentry, const char * symname)
  140. {
  141. struct super_block * sb = dir->i_sb;
  142. int err = -ENAMETOOLONG;
  143. unsigned l = strlen(symname)+1;
  144. struct inode * inode;
  145. if (l > sb->s_blocksize)
  146. goto out;
  147. err = dquot_initialize(dir);
  148. if (err)
  149. goto out;
  150. inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name);
  151. err = PTR_ERR(inode);
  152. if (IS_ERR(inode))
  153. goto out;
  154. if (l > sizeof (EXT2_I(inode)->i_data)) {
  155. /* slow symlink */
  156. inode->i_op = &ext2_symlink_inode_operations;
  157. inode_nohighmem(inode);
  158. inode->i_mapping->a_ops = &ext2_aops;
  159. err = page_symlink(inode, symname, l);
  160. if (err)
  161. goto out_fail;
  162. } else {
  163. /* fast symlink */
  164. inode->i_op = &ext2_fast_symlink_inode_operations;
  165. inode->i_link = (char*)EXT2_I(inode)->i_data;
  166. memcpy(inode->i_link, symname, l);
  167. inode->i_size = l-1;
  168. }
  169. mark_inode_dirty(inode);
  170. err = ext2_add_nondir(dentry, inode);
  171. out:
  172. return err;
  173. out_fail:
  174. inode_dec_link_count(inode);
  175. discard_new_inode(inode);
  176. goto out;
  177. }
  178. static int ext2_link (struct dentry * old_dentry, struct inode * dir,
  179. struct dentry *dentry)
  180. {
  181. struct inode *inode = d_inode(old_dentry);
  182. int err;
  183. err = dquot_initialize(dir);
  184. if (err)
  185. return err;
  186. inode->i_ctime = current_time(inode);
  187. inode_inc_link_count(inode);
  188. ihold(inode);
  189. err = ext2_add_link(dentry, inode);
  190. if (!err) {
  191. d_instantiate(dentry, inode);
  192. return 0;
  193. }
  194. inode_dec_link_count(inode);
  195. iput(inode);
  196. return err;
  197. }
  198. static int ext2_mkdir(struct user_namespace * mnt_userns,
  199. struct inode * dir, struct dentry * dentry, umode_t mode)
  200. {
  201. struct inode * inode;
  202. int err;
  203. err = dquot_initialize(dir);
  204. if (err)
  205. return err;
  206. inode_inc_link_count(dir);
  207. inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name);
  208. err = PTR_ERR(inode);
  209. if (IS_ERR(inode))
  210. goto out_dir;
  211. inode->i_op = &ext2_dir_inode_operations;
  212. inode->i_fop = &ext2_dir_operations;
  213. inode->i_mapping->a_ops = &ext2_aops;
  214. inode_inc_link_count(inode);
  215. err = ext2_make_empty(inode, dir);
  216. if (err)
  217. goto out_fail;
  218. err = ext2_add_link(dentry, inode);
  219. if (err)
  220. goto out_fail;
  221. d_instantiate_new(dentry, inode);
  222. out:
  223. return err;
  224. out_fail:
  225. inode_dec_link_count(inode);
  226. inode_dec_link_count(inode);
  227. discard_new_inode(inode);
  228. out_dir:
  229. inode_dec_link_count(dir);
  230. goto out;
  231. }
  232. static int ext2_unlink(struct inode * dir, struct dentry *dentry)
  233. {
  234. struct inode * inode = d_inode(dentry);
  235. struct ext2_dir_entry_2 * de;
  236. struct page * page;
  237. void *page_addr;
  238. int err;
  239. err = dquot_initialize(dir);
  240. if (err)
  241. goto out;
  242. de = ext2_find_entry(dir, &dentry->d_name, &page, &page_addr);
  243. if (IS_ERR(de)) {
  244. err = PTR_ERR(de);
  245. goto out;
  246. }
  247. err = ext2_delete_entry (de, page, page_addr);
  248. ext2_put_page(page, page_addr);
  249. if (err)
  250. goto out;
  251. inode->i_ctime = dir->i_ctime;
  252. inode_dec_link_count(inode);
  253. err = 0;
  254. out:
  255. return err;
  256. }
  257. static int ext2_rmdir (struct inode * dir, struct dentry *dentry)
  258. {
  259. struct inode * inode = d_inode(dentry);
  260. int err = -ENOTEMPTY;
  261. if (ext2_empty_dir(inode)) {
  262. err = ext2_unlink(dir, dentry);
  263. if (!err) {
  264. inode->i_size = 0;
  265. inode_dec_link_count(inode);
  266. inode_dec_link_count(dir);
  267. }
  268. }
  269. return err;
  270. }
  271. static int ext2_rename (struct user_namespace * mnt_userns,
  272. struct inode * old_dir, struct dentry * old_dentry,
  273. struct inode * new_dir, struct dentry * new_dentry,
  274. unsigned int flags)
  275. {
  276. struct inode * old_inode = d_inode(old_dentry);
  277. struct inode * new_inode = d_inode(new_dentry);
  278. struct page * dir_page = NULL;
  279. void *dir_page_addr;
  280. struct ext2_dir_entry_2 * dir_de = NULL;
  281. struct page * old_page;
  282. void *old_page_addr;
  283. struct ext2_dir_entry_2 * old_de;
  284. int err;
  285. if (flags & ~RENAME_NOREPLACE)
  286. return -EINVAL;
  287. err = dquot_initialize(old_dir);
  288. if (err)
  289. goto out;
  290. err = dquot_initialize(new_dir);
  291. if (err)
  292. goto out;
  293. old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_page,
  294. &old_page_addr);
  295. if (IS_ERR(old_de)) {
  296. err = PTR_ERR(old_de);
  297. goto out;
  298. }
  299. if (S_ISDIR(old_inode->i_mode)) {
  300. err = -EIO;
  301. dir_de = ext2_dotdot(old_inode, &dir_page, &dir_page_addr);
  302. if (!dir_de)
  303. goto out_old;
  304. }
  305. if (new_inode) {
  306. void *page_addr;
  307. struct page *new_page;
  308. struct ext2_dir_entry_2 *new_de;
  309. err = -ENOTEMPTY;
  310. if (dir_de && !ext2_empty_dir (new_inode))
  311. goto out_dir;
  312. new_de = ext2_find_entry(new_dir, &new_dentry->d_name,
  313. &new_page, &page_addr);
  314. if (IS_ERR(new_de)) {
  315. err = PTR_ERR(new_de);
  316. goto out_dir;
  317. }
  318. ext2_set_link(new_dir, new_de, new_page, page_addr, old_inode, 1);
  319. ext2_put_page(new_page, page_addr);
  320. new_inode->i_ctime = current_time(new_inode);
  321. if (dir_de)
  322. drop_nlink(new_inode);
  323. inode_dec_link_count(new_inode);
  324. } else {
  325. err = ext2_add_link(new_dentry, old_inode);
  326. if (err)
  327. goto out_dir;
  328. if (dir_de)
  329. inode_inc_link_count(new_dir);
  330. }
  331. /*
  332. * Like most other Unix systems, set the ctime for inodes on a
  333. * rename.
  334. */
  335. old_inode->i_ctime = current_time(old_inode);
  336. mark_inode_dirty(old_inode);
  337. ext2_delete_entry(old_de, old_page, old_page_addr);
  338. if (dir_de) {
  339. if (old_dir != new_dir)
  340. ext2_set_link(old_inode, dir_de, dir_page,
  341. dir_page_addr, new_dir, 0);
  342. ext2_put_page(dir_page, dir_page_addr);
  343. inode_dec_link_count(old_dir);
  344. }
  345. ext2_put_page(old_page, old_page_addr);
  346. return 0;
  347. out_dir:
  348. if (dir_de)
  349. ext2_put_page(dir_page, dir_page_addr);
  350. out_old:
  351. ext2_put_page(old_page, old_page_addr);
  352. out:
  353. return err;
  354. }
  355. const struct inode_operations ext2_dir_inode_operations = {
  356. .create = ext2_create,
  357. .lookup = ext2_lookup,
  358. .link = ext2_link,
  359. .unlink = ext2_unlink,
  360. .symlink = ext2_symlink,
  361. .mkdir = ext2_mkdir,
  362. .rmdir = ext2_rmdir,
  363. .mknod = ext2_mknod,
  364. .rename = ext2_rename,
  365. .listxattr = ext2_listxattr,
  366. .getattr = ext2_getattr,
  367. .setattr = ext2_setattr,
  368. .get_acl = ext2_get_acl,
  369. .set_acl = ext2_set_acl,
  370. .tmpfile = ext2_tmpfile,
  371. .fileattr_get = ext2_fileattr_get,
  372. .fileattr_set = ext2_fileattr_set,
  373. };
  374. const struct inode_operations ext2_special_inode_operations = {
  375. .listxattr = ext2_listxattr,
  376. .getattr = ext2_getattr,
  377. .setattr = ext2_setattr,
  378. .get_acl = ext2_get_acl,
  379. .set_acl = ext2_set_acl,
  380. };