dir.c 8.5 KB

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  1. /*
  2. * fs/bfs/dir.c
  3. * BFS directory operations.
  4. * Copyright (C) 1999,2000 Tigran Aivazian <tigran@veritas.com>
  5. * Made endianness-clean by Andrew Stribblehill <ads@wompom.org> 2005
  6. */
  7. #include <linux/time.h>
  8. #include <linux/string.h>
  9. #include <linux/fs.h>
  10. #include <linux/smp_lock.h>
  11. #include <linux/buffer_head.h>
  12. #include <linux/sched.h>
  13. #include "bfs.h"
  14. #undef DEBUG
  15. #ifdef DEBUG
  16. #define dprintf(x...) printf(x)
  17. #else
  18. #define dprintf(x...)
  19. #endif
  20. static int bfs_add_entry(struct inode * dir, const unsigned char * name, int namelen, int ino);
  21. static struct buffer_head * bfs_find_entry(struct inode * dir,
  22. const unsigned char * name, int namelen, struct bfs_dirent ** res_dir);
  23. static int bfs_readdir(struct file * f, void * dirent, filldir_t filldir)
  24. {
  25. struct inode * dir = f->f_path.dentry->d_inode;
  26. struct buffer_head * bh;
  27. struct bfs_dirent * de;
  28. unsigned int offset;
  29. int block;
  30. lock_kernel();
  31. if (f->f_pos & (BFS_DIRENT_SIZE-1)) {
  32. printf("Bad f_pos=%08lx for %s:%08lx\n", (unsigned long)f->f_pos,
  33. dir->i_sb->s_id, dir->i_ino);
  34. unlock_kernel();
  35. return -EBADF;
  36. }
  37. while (f->f_pos < dir->i_size) {
  38. offset = f->f_pos & (BFS_BSIZE-1);
  39. block = BFS_I(dir)->i_sblock + (f->f_pos >> BFS_BSIZE_BITS);
  40. bh = sb_bread(dir->i_sb, block);
  41. if (!bh) {
  42. f->f_pos += BFS_BSIZE - offset;
  43. continue;
  44. }
  45. do {
  46. de = (struct bfs_dirent *)(bh->b_data + offset);
  47. if (de->ino) {
  48. int size = strnlen(de->name, BFS_NAMELEN);
  49. if (filldir(dirent, de->name, size, f->f_pos, le16_to_cpu(de->ino), DT_UNKNOWN) < 0) {
  50. brelse(bh);
  51. unlock_kernel();
  52. return 0;
  53. }
  54. }
  55. offset += BFS_DIRENT_SIZE;
  56. f->f_pos += BFS_DIRENT_SIZE;
  57. } while (offset < BFS_BSIZE && f->f_pos < dir->i_size);
  58. brelse(bh);
  59. }
  60. unlock_kernel();
  61. return 0;
  62. }
  63. const struct file_operations bfs_dir_operations = {
  64. .read = generic_read_dir,
  65. .readdir = bfs_readdir,
  66. .fsync = file_fsync,
  67. };
  68. extern void dump_imap(const char *, struct super_block *);
  69. static int bfs_create(struct inode * dir, struct dentry * dentry, int mode,
  70. struct nameidata *nd)
  71. {
  72. int err;
  73. struct inode * inode;
  74. struct super_block * s = dir->i_sb;
  75. struct bfs_sb_info * info = BFS_SB(s);
  76. unsigned long ino;
  77. inode = new_inode(s);
  78. if (!inode)
  79. return -ENOSPC;
  80. lock_kernel();
  81. ino = find_first_zero_bit(info->si_imap, info->si_lasti);
  82. if (ino > info->si_lasti) {
  83. unlock_kernel();
  84. iput(inode);
  85. return -ENOSPC;
  86. }
  87. set_bit(ino, info->si_imap);
  88. info->si_freei--;
  89. inode->i_uid = current->fsuid;
  90. inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid;
  91. inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
  92. inode->i_blocks = 0;
  93. inode->i_op = &bfs_file_inops;
  94. inode->i_fop = &bfs_file_operations;
  95. inode->i_mapping->a_ops = &bfs_aops;
  96. inode->i_mode = mode;
  97. inode->i_ino = ino;
  98. BFS_I(inode)->i_dsk_ino = ino;
  99. BFS_I(inode)->i_sblock = 0;
  100. BFS_I(inode)->i_eblock = 0;
  101. insert_inode_hash(inode);
  102. mark_inode_dirty(inode);
  103. dump_imap("create",s);
  104. err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len, inode->i_ino);
  105. if (err) {
  106. inode_dec_link_count(inode);
  107. iput(inode);
  108. unlock_kernel();
  109. return err;
  110. }
  111. unlock_kernel();
  112. d_instantiate(dentry, inode);
  113. return 0;
  114. }
  115. static struct dentry * bfs_lookup(struct inode * dir, struct dentry * dentry, struct nameidata *nd)
  116. {
  117. struct inode * inode = NULL;
  118. struct buffer_head * bh;
  119. struct bfs_dirent * de;
  120. if (dentry->d_name.len > BFS_NAMELEN)
  121. return ERR_PTR(-ENAMETOOLONG);
  122. lock_kernel();
  123. bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
  124. if (bh) {
  125. unsigned long ino = (unsigned long)le16_to_cpu(de->ino);
  126. brelse(bh);
  127. inode = iget(dir->i_sb, ino);
  128. if (!inode) {
  129. unlock_kernel();
  130. return ERR_PTR(-EACCES);
  131. }
  132. }
  133. unlock_kernel();
  134. d_add(dentry, inode);
  135. return NULL;
  136. }
  137. static int bfs_link(struct dentry * old, struct inode * dir, struct dentry * new)
  138. {
  139. struct inode * inode = old->d_inode;
  140. int err;
  141. lock_kernel();
  142. err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, inode->i_ino);
  143. if (err) {
  144. unlock_kernel();
  145. return err;
  146. }
  147. inc_nlink(inode);
  148. inode->i_ctime = CURRENT_TIME_SEC;
  149. mark_inode_dirty(inode);
  150. atomic_inc(&inode->i_count);
  151. d_instantiate(new, inode);
  152. unlock_kernel();
  153. return 0;
  154. }
  155. static int bfs_unlink(struct inode * dir, struct dentry * dentry)
  156. {
  157. int error = -ENOENT;
  158. struct inode * inode;
  159. struct buffer_head * bh;
  160. struct bfs_dirent * de;
  161. inode = dentry->d_inode;
  162. lock_kernel();
  163. bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de);
  164. if (!bh || le16_to_cpu(de->ino) != inode->i_ino)
  165. goto out_brelse;
  166. if (!inode->i_nlink) {
  167. printf("unlinking non-existent file %s:%lu (nlink=%d)\n", inode->i_sb->s_id,
  168. inode->i_ino, inode->i_nlink);
  169. inode->i_nlink = 1;
  170. }
  171. de->ino = 0;
  172. mark_buffer_dirty(bh);
  173. dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC;
  174. mark_inode_dirty(dir);
  175. inode->i_ctime = dir->i_ctime;
  176. inode_dec_link_count(inode);
  177. error = 0;
  178. out_brelse:
  179. brelse(bh);
  180. unlock_kernel();
  181. return error;
  182. }
  183. static int bfs_rename(struct inode * old_dir, struct dentry * old_dentry,
  184. struct inode * new_dir, struct dentry * new_dentry)
  185. {
  186. struct inode * old_inode, * new_inode;
  187. struct buffer_head * old_bh, * new_bh;
  188. struct bfs_dirent * old_de, * new_de;
  189. int error = -ENOENT;
  190. old_bh = new_bh = NULL;
  191. old_inode = old_dentry->d_inode;
  192. if (S_ISDIR(old_inode->i_mode))
  193. return -EINVAL;
  194. lock_kernel();
  195. old_bh = bfs_find_entry(old_dir,
  196. old_dentry->d_name.name,
  197. old_dentry->d_name.len, &old_de);
  198. if (!old_bh || le16_to_cpu(old_de->ino) != old_inode->i_ino)
  199. goto end_rename;
  200. error = -EPERM;
  201. new_inode = new_dentry->d_inode;
  202. new_bh = bfs_find_entry(new_dir,
  203. new_dentry->d_name.name,
  204. new_dentry->d_name.len, &new_de);
  205. if (new_bh && !new_inode) {
  206. brelse(new_bh);
  207. new_bh = NULL;
  208. }
  209. if (!new_bh) {
  210. error = bfs_add_entry(new_dir,
  211. new_dentry->d_name.name,
  212. new_dentry->d_name.len, old_inode->i_ino);
  213. if (error)
  214. goto end_rename;
  215. }
  216. old_de->ino = 0;
  217. old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC;
  218. mark_inode_dirty(old_dir);
  219. if (new_inode) {
  220. new_inode->i_ctime = CURRENT_TIME_SEC;
  221. inode_dec_link_count(new_inode);
  222. }
  223. mark_buffer_dirty(old_bh);
  224. error = 0;
  225. end_rename:
  226. unlock_kernel();
  227. brelse(old_bh);
  228. brelse(new_bh);
  229. return error;
  230. }
  231. const struct inode_operations bfs_dir_inops = {
  232. .create = bfs_create,
  233. .lookup = bfs_lookup,
  234. .link = bfs_link,
  235. .unlink = bfs_unlink,
  236. .rename = bfs_rename,
  237. };
  238. static int bfs_add_entry(struct inode * dir, const unsigned char * name, int namelen, int ino)
  239. {
  240. struct buffer_head * bh;
  241. struct bfs_dirent * de;
  242. int block, sblock, eblock, off, eoff;
  243. int i;
  244. dprintf("name=%s, namelen=%d\n", name, namelen);
  245. if (!namelen)
  246. return -ENOENT;
  247. if (namelen > BFS_NAMELEN)
  248. return -ENAMETOOLONG;
  249. sblock = BFS_I(dir)->i_sblock;
  250. eblock = BFS_I(dir)->i_eblock;
  251. eoff = dir->i_size % BFS_BSIZE;
  252. for (block=sblock; block<=eblock; block++) {
  253. bh = sb_bread(dir->i_sb, block);
  254. if(!bh)
  255. return -ENOSPC;
  256. for (off=0; off<BFS_BSIZE; off+=BFS_DIRENT_SIZE) {
  257. de = (struct bfs_dirent *)(bh->b_data + off);
  258. if (block==eblock && off>=eoff) {
  259. /* Do not read/interpret the garbage in the end of eblock. */
  260. de->ino = 0;
  261. }
  262. if (!de->ino) {
  263. if ((block-sblock)*BFS_BSIZE + off >= dir->i_size) {
  264. dir->i_size += BFS_DIRENT_SIZE;
  265. dir->i_ctime = CURRENT_TIME_SEC;
  266. }
  267. dir->i_mtime = CURRENT_TIME_SEC;
  268. mark_inode_dirty(dir);
  269. de->ino = cpu_to_le16((u16)ino);
  270. for (i=0; i<BFS_NAMELEN; i++)
  271. de->name[i] = (i < namelen) ? name[i] : 0;
  272. mark_buffer_dirty(bh);
  273. brelse(bh);
  274. return 0;
  275. }
  276. }
  277. brelse(bh);
  278. }
  279. return -ENOSPC;
  280. }
  281. static inline int bfs_namecmp(int len, const unsigned char * name, const char * buffer)
  282. {
  283. if (len < BFS_NAMELEN && buffer[len])
  284. return 0;
  285. return !memcmp(name, buffer, len);
  286. }
  287. static struct buffer_head * bfs_find_entry(struct inode * dir,
  288. const unsigned char * name, int namelen, struct bfs_dirent ** res_dir)
  289. {
  290. unsigned long block, offset;
  291. struct buffer_head * bh;
  292. struct bfs_dirent * de;
  293. *res_dir = NULL;
  294. if (namelen > BFS_NAMELEN)
  295. return NULL;
  296. bh = NULL;
  297. block = offset = 0;
  298. while (block * BFS_BSIZE + offset < dir->i_size) {
  299. if (!bh) {
  300. bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block);
  301. if (!bh) {
  302. block++;
  303. continue;
  304. }
  305. }
  306. de = (struct bfs_dirent *)(bh->b_data + offset);
  307. offset += BFS_DIRENT_SIZE;
  308. if (le16_to_cpu(de->ino) && bfs_namecmp(namelen, name, de->name)) {
  309. *res_dir = de;
  310. return bh;
  311. }
  312. if (offset < bh->b_size)
  313. continue;
  314. brelse(bh);
  315. bh = NULL;
  316. offset = 0;
  317. block++;
  318. }
  319. brelse(bh);
  320. return NULL;
  321. }