namei.c 6.2 KB

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  1. /*
  2. * linux/fs/sysv/namei.c
  3. *
  4. * minix/namei.c
  5. * Copyright (C) 1991, 1992 Linus Torvalds
  6. *
  7. * coh/namei.c
  8. * Copyright (C) 1993 Pascal Haible, Bruno Haible
  9. *
  10. * sysv/namei.c
  11. * Copyright (C) 1993 Bruno Haible
  12. * Copyright (C) 1997, 1998 Krzysztof G. Baranowski
  13. */
  14. #include <linux/pagemap.h>
  15. #include <linux/smp_lock.h>
  16. #include "sysv.h"
  17. static int add_nondir(struct dentry *dentry, struct inode *inode)
  18. {
  19. int err = sysv_add_link(dentry, inode);
  20. if (!err) {
  21. d_instantiate(dentry, inode);
  22. return 0;
  23. }
  24. inode_dec_link_count(inode);
  25. iput(inode);
  26. return err;
  27. }
  28. static int sysv_hash(struct dentry *dentry, struct qstr *qstr)
  29. {
  30. /* Truncate the name in place, avoids having to define a compare
  31. function. */
  32. if (qstr->len > SYSV_NAMELEN) {
  33. qstr->len = SYSV_NAMELEN;
  34. qstr->hash = full_name_hash(qstr->name, qstr->len);
  35. }
  36. return 0;
  37. }
  38. struct dentry_operations sysv_dentry_operations = {
  39. .d_hash = sysv_hash,
  40. };
  41. static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
  42. {
  43. struct inode * inode = NULL;
  44. ino_t ino;
  45. dentry->d_op = dir->i_sb->s_root->d_op;
  46. if (dentry->d_name.len > SYSV_NAMELEN)
  47. return ERR_PTR(-ENAMETOOLONG);
  48. ino = sysv_inode_by_name(dentry);
  49. if (ino) {
  50. inode = iget(dir->i_sb, ino);
  51. if (!inode)
  52. return ERR_PTR(-EACCES);
  53. }
  54. d_add(dentry, inode);
  55. return NULL;
  56. }
  57. static int sysv_mknod(struct inode * dir, struct dentry * dentry, int mode, dev_t rdev)
  58. {
  59. struct inode * inode;
  60. int err;
  61. if (!old_valid_dev(rdev))
  62. return -EINVAL;
  63. inode = sysv_new_inode(dir, mode);
  64. err = PTR_ERR(inode);
  65. if (!IS_ERR(inode)) {
  66. sysv_set_inode(inode, rdev);
  67. mark_inode_dirty(inode);
  68. err = add_nondir(dentry, inode);
  69. }
  70. return err;
  71. }
  72. static int sysv_create(struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd)
  73. {
  74. return sysv_mknod(dir, dentry, mode, 0);
  75. }
  76. static int sysv_symlink(struct inode * dir, struct dentry * dentry,
  77. const char * symname)
  78. {
  79. int err = -ENAMETOOLONG;
  80. int l = strlen(symname)+1;
  81. struct inode * inode;
  82. if (l > dir->i_sb->s_blocksize)
  83. goto out;
  84. inode = sysv_new_inode(dir, S_IFLNK|0777);
  85. err = PTR_ERR(inode);
  86. if (IS_ERR(inode))
  87. goto out;
  88. sysv_set_inode(inode, 0);
  89. err = page_symlink(inode, symname, l);
  90. if (err)
  91. goto out_fail;
  92. mark_inode_dirty(inode);
  93. err = add_nondir(dentry, inode);
  94. out:
  95. return err;
  96. out_fail:
  97. inode_dec_link_count(inode);
  98. iput(inode);
  99. goto out;
  100. }
  101. static int sysv_link(struct dentry * old_dentry, struct inode * dir,
  102. struct dentry * dentry)
  103. {
  104. struct inode *inode = old_dentry->d_inode;
  105. if (inode->i_nlink >= SYSV_SB(inode->i_sb)->s_link_max)
  106. return -EMLINK;
  107. inode->i_ctime = CURRENT_TIME_SEC;
  108. inode_inc_link_count(inode);
  109. atomic_inc(&inode->i_count);
  110. return add_nondir(dentry, inode);
  111. }
  112. static int sysv_mkdir(struct inode * dir, struct dentry *dentry, int mode)
  113. {
  114. struct inode * inode;
  115. int err = -EMLINK;
  116. if (dir->i_nlink >= SYSV_SB(dir->i_sb)->s_link_max)
  117. goto out;
  118. inode_inc_link_count(dir);
  119. inode = sysv_new_inode(dir, S_IFDIR|mode);
  120. err = PTR_ERR(inode);
  121. if (IS_ERR(inode))
  122. goto out_dir;
  123. sysv_set_inode(inode, 0);
  124. inode_inc_link_count(inode);
  125. err = sysv_make_empty(inode, dir);
  126. if (err)
  127. goto out_fail;
  128. err = sysv_add_link(dentry, inode);
  129. if (err)
  130. goto out_fail;
  131. d_instantiate(dentry, inode);
  132. out:
  133. return err;
  134. out_fail:
  135. inode_dec_link_count(inode);
  136. inode_dec_link_count(inode);
  137. iput(inode);
  138. out_dir:
  139. inode_dec_link_count(dir);
  140. goto out;
  141. }
  142. static int sysv_unlink(struct inode * dir, struct dentry * dentry)
  143. {
  144. struct inode * inode = dentry->d_inode;
  145. struct page * page;
  146. struct sysv_dir_entry * de;
  147. int err = -ENOENT;
  148. de = sysv_find_entry(dentry, &page);
  149. if (!de)
  150. goto out;
  151. err = sysv_delete_entry (de, page);
  152. if (err)
  153. goto out;
  154. inode->i_ctime = dir->i_ctime;
  155. inode_dec_link_count(inode);
  156. out:
  157. return err;
  158. }
  159. static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
  160. {
  161. struct inode *inode = dentry->d_inode;
  162. int err = -ENOTEMPTY;
  163. if (sysv_empty_dir(inode)) {
  164. err = sysv_unlink(dir, dentry);
  165. if (!err) {
  166. inode->i_size = 0;
  167. inode_dec_link_count(inode);
  168. inode_dec_link_count(dir);
  169. }
  170. }
  171. return err;
  172. }
  173. /*
  174. * Anybody can rename anything with this: the permission checks are left to the
  175. * higher-level routines.
  176. */
  177. static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
  178. struct inode * new_dir, struct dentry * new_dentry)
  179. {
  180. struct inode * old_inode = old_dentry->d_inode;
  181. struct inode * new_inode = new_dentry->d_inode;
  182. struct page * dir_page = NULL;
  183. struct sysv_dir_entry * dir_de = NULL;
  184. struct page * old_page;
  185. struct sysv_dir_entry * old_de;
  186. int err = -ENOENT;
  187. old_de = sysv_find_entry(old_dentry, &old_page);
  188. if (!old_de)
  189. goto out;
  190. if (S_ISDIR(old_inode->i_mode)) {
  191. err = -EIO;
  192. dir_de = sysv_dotdot(old_inode, &dir_page);
  193. if (!dir_de)
  194. goto out_old;
  195. }
  196. if (new_inode) {
  197. struct page * new_page;
  198. struct sysv_dir_entry * new_de;
  199. err = -ENOTEMPTY;
  200. if (dir_de && !sysv_empty_dir(new_inode))
  201. goto out_dir;
  202. err = -ENOENT;
  203. new_de = sysv_find_entry(new_dentry, &new_page);
  204. if (!new_de)
  205. goto out_dir;
  206. inode_inc_link_count(old_inode);
  207. sysv_set_link(new_de, new_page, old_inode);
  208. new_inode->i_ctime = CURRENT_TIME_SEC;
  209. if (dir_de)
  210. drop_nlink(new_inode);
  211. inode_dec_link_count(new_inode);
  212. } else {
  213. if (dir_de) {
  214. err = -EMLINK;
  215. if (new_dir->i_nlink >= SYSV_SB(new_dir->i_sb)->s_link_max)
  216. goto out_dir;
  217. }
  218. inode_inc_link_count(old_inode);
  219. err = sysv_add_link(new_dentry, old_inode);
  220. if (err) {
  221. inode_dec_link_count(old_inode);
  222. goto out_dir;
  223. }
  224. if (dir_de)
  225. inode_inc_link_count(new_dir);
  226. }
  227. sysv_delete_entry(old_de, old_page);
  228. inode_dec_link_count(old_inode);
  229. if (dir_de) {
  230. sysv_set_link(dir_de, dir_page, new_dir);
  231. inode_dec_link_count(old_dir);
  232. }
  233. return 0;
  234. out_dir:
  235. if (dir_de) {
  236. kunmap(dir_page);
  237. page_cache_release(dir_page);
  238. }
  239. out_old:
  240. kunmap(old_page);
  241. page_cache_release(old_page);
  242. out:
  243. return err;
  244. }
  245. /*
  246. * directories can handle most operations...
  247. */
  248. const struct inode_operations sysv_dir_inode_operations = {
  249. .create = sysv_create,
  250. .lookup = sysv_lookup,
  251. .link = sysv_link,
  252. .unlink = sysv_unlink,
  253. .symlink = sysv_symlink,
  254. .mkdir = sysv_mkdir,
  255. .rmdir = sysv_rmdir,
  256. .mknod = sysv_mknod,
  257. .rename = sysv_rename,
  258. .getattr = sysv_getattr,
  259. };