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 8 #include <linux/time.h> 9 #include <linux/string.h> 10 #include <linux/fs.h> 11 #include <linux/buffer_head.h> 12 #include <linux/sched.h> 13 #include "bfs.h" 14 15 #undef DEBUG 16 17 #ifdef DEBUG 18 #define dprintf(x...) printf(x) 19 #else 20 #define dprintf(x...) 21 #endif 22 23 static int bfs_add_entry(struct inode *dir, const unsigned char *name, 24 int namelen, int ino); 25 static struct buffer_head *bfs_find_entry(struct inode *dir, 26 const unsigned char *name, int namelen, 27 struct bfs_dirent **res_dir); 28 29 static int bfs_readdir(struct file *f, void *dirent, filldir_t filldir) 30 { 31 struct inode *dir = file_inode(f); 32 struct buffer_head *bh; 33 struct bfs_dirent *de; 34 struct bfs_sb_info *info = BFS_SB(dir->i_sb); 35 unsigned int offset; 36 int block; 37 38 mutex_lock(&info->bfs_lock); 39 40 if (f->f_pos & (BFS_DIRENT_SIZE - 1)) { 41 printf("Bad f_pos=%08lx for %s:%08lx\n", 42 (unsigned long)f->f_pos, 43 dir->i_sb->s_id, dir->i_ino); 44 mutex_unlock(&info->bfs_lock); 45 return -EBADF; 46 } 47 48 while (f->f_pos < dir->i_size) { 49 offset = f->f_pos & (BFS_BSIZE - 1); 50 block = BFS_I(dir)->i_sblock + (f->f_pos >> BFS_BSIZE_BITS); 51 bh = sb_bread(dir->i_sb, block); 52 if (!bh) { 53 f->f_pos += BFS_BSIZE - offset; 54 continue; 55 } 56 do { 57 de = (struct bfs_dirent *)(bh->b_data + offset); 58 if (de->ino) { 59 int size = strnlen(de->name, BFS_NAMELEN); 60 if (filldir(dirent, de->name, size, f->f_pos, 61 le16_to_cpu(de->ino), 62 DT_UNKNOWN) < 0) { 63 brelse(bh); 64 mutex_unlock(&info->bfs_lock); 65 return 0; 66 } 67 } 68 offset += BFS_DIRENT_SIZE; 69 f->f_pos += BFS_DIRENT_SIZE; 70 } while ((offset < BFS_BSIZE) && (f->f_pos < dir->i_size)); 71 brelse(bh); 72 } 73 74 mutex_unlock(&info->bfs_lock); 75 return 0; 76 } 77 78 const struct file_operations bfs_dir_operations = { 79 .read = generic_read_dir, 80 .readdir = bfs_readdir, 81 .fsync = generic_file_fsync, 82 .llseek = generic_file_llseek, 83 }; 84 85 extern void dump_imap(const char *, struct super_block *); 86 87 static int bfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, 88 bool excl) 89 { 90 int err; 91 struct inode *inode; 92 struct super_block *s = dir->i_sb; 93 struct bfs_sb_info *info = BFS_SB(s); 94 unsigned long ino; 95 96 inode = new_inode(s); 97 if (!inode) 98 return -ENOSPC; 99 mutex_lock(&info->bfs_lock); 100 ino = find_first_zero_bit(info->si_imap, info->si_lasti + 1); 101 if (ino > info->si_lasti) { 102 mutex_unlock(&info->bfs_lock); 103 iput(inode); 104 return -ENOSPC; 105 } 106 set_bit(ino, info->si_imap); 107 info->si_freei--; 108 inode_init_owner(inode, dir, mode); 109 inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC; 110 inode->i_blocks = 0; 111 inode->i_op = &bfs_file_inops; 112 inode->i_fop = &bfs_file_operations; 113 inode->i_mapping->a_ops = &bfs_aops; 114 inode->i_ino = ino; 115 BFS_I(inode)->i_dsk_ino = ino; 116 BFS_I(inode)->i_sblock = 0; 117 BFS_I(inode)->i_eblock = 0; 118 insert_inode_hash(inode); 119 mark_inode_dirty(inode); 120 dump_imap("create", s); 121 122 err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len, 123 inode->i_ino); 124 if (err) { 125 inode_dec_link_count(inode); 126 mutex_unlock(&info->bfs_lock); 127 iput(inode); 128 return err; 129 } 130 mutex_unlock(&info->bfs_lock); 131 d_instantiate(dentry, inode); 132 return 0; 133 } 134 135 static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry, 136 unsigned int flags) 137 { 138 struct inode *inode = NULL; 139 struct buffer_head *bh; 140 struct bfs_dirent *de; 141 struct bfs_sb_info *info = BFS_SB(dir->i_sb); 142 143 if (dentry->d_name.len > BFS_NAMELEN) 144 return ERR_PTR(-ENAMETOOLONG); 145 146 mutex_lock(&info->bfs_lock); 147 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de); 148 if (bh) { 149 unsigned long ino = (unsigned long)le16_to_cpu(de->ino); 150 brelse(bh); 151 inode = bfs_iget(dir->i_sb, ino); 152 if (IS_ERR(inode)) { 153 mutex_unlock(&info->bfs_lock); 154 return ERR_CAST(inode); 155 } 156 } 157 mutex_unlock(&info->bfs_lock); 158 d_add(dentry, inode); 159 return NULL; 160 } 161 162 static int bfs_link(struct dentry *old, struct inode *dir, 163 struct dentry *new) 164 { 165 struct inode *inode = old->d_inode; 166 struct bfs_sb_info *info = BFS_SB(inode->i_sb); 167 int err; 168 169 mutex_lock(&info->bfs_lock); 170 err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, 171 inode->i_ino); 172 if (err) { 173 mutex_unlock(&info->bfs_lock); 174 return err; 175 } 176 inc_nlink(inode); 177 inode->i_ctime = CURRENT_TIME_SEC; 178 mark_inode_dirty(inode); 179 ihold(inode); 180 d_instantiate(new, inode); 181 mutex_unlock(&info->bfs_lock); 182 return 0; 183 } 184 185 static int bfs_unlink(struct inode *dir, struct dentry *dentry) 186 { 187 int error = -ENOENT; 188 struct inode *inode = dentry->d_inode; 189 struct buffer_head *bh; 190 struct bfs_dirent *de; 191 struct bfs_sb_info *info = BFS_SB(inode->i_sb); 192 193 mutex_lock(&info->bfs_lock); 194 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de); 195 if (!bh || (le16_to_cpu(de->ino) != inode->i_ino)) 196 goto out_brelse; 197 198 if (!inode->i_nlink) { 199 printf("unlinking non-existent file %s:%lu (nlink=%d)\n", 200 inode->i_sb->s_id, inode->i_ino, 201 inode->i_nlink); 202 set_nlink(inode, 1); 203 } 204 de->ino = 0; 205 mark_buffer_dirty_inode(bh, dir); 206 dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC; 207 mark_inode_dirty(dir); 208 inode->i_ctime = dir->i_ctime; 209 inode_dec_link_count(inode); 210 error = 0; 211 212 out_brelse: 213 brelse(bh); 214 mutex_unlock(&info->bfs_lock); 215 return error; 216 } 217 218 static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry, 219 struct inode *new_dir, struct dentry *new_dentry) 220 { 221 struct inode *old_inode, *new_inode; 222 struct buffer_head *old_bh, *new_bh; 223 struct bfs_dirent *old_de, *new_de; 224 struct bfs_sb_info *info; 225 int error = -ENOENT; 226 227 old_bh = new_bh = NULL; 228 old_inode = old_dentry->d_inode; 229 if (S_ISDIR(old_inode->i_mode)) 230 return -EINVAL; 231 232 info = BFS_SB(old_inode->i_sb); 233 234 mutex_lock(&info->bfs_lock); 235 old_bh = bfs_find_entry(old_dir, 236 old_dentry->d_name.name, 237 old_dentry->d_name.len, &old_de); 238 239 if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino)) 240 goto end_rename; 241 242 error = -EPERM; 243 new_inode = new_dentry->d_inode; 244 new_bh = bfs_find_entry(new_dir, 245 new_dentry->d_name.name, 246 new_dentry->d_name.len, &new_de); 247 248 if (new_bh && !new_inode) { 249 brelse(new_bh); 250 new_bh = NULL; 251 } 252 if (!new_bh) { 253 error = bfs_add_entry(new_dir, 254 new_dentry->d_name.name, 255 new_dentry->d_name.len, 256 old_inode->i_ino); 257 if (error) 258 goto end_rename; 259 } 260 old_de->ino = 0; 261 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC; 262 mark_inode_dirty(old_dir); 263 if (new_inode) { 264 new_inode->i_ctime = CURRENT_TIME_SEC; 265 inode_dec_link_count(new_inode); 266 } 267 mark_buffer_dirty_inode(old_bh, old_dir); 268 error = 0; 269 270 end_rename: 271 mutex_unlock(&info->bfs_lock); 272 brelse(old_bh); 273 brelse(new_bh); 274 return error; 275 } 276 277 const struct inode_operations bfs_dir_inops = { 278 .create = bfs_create, 279 .lookup = bfs_lookup, 280 .link = bfs_link, 281 .unlink = bfs_unlink, 282 .rename = bfs_rename, 283 }; 284 285 static int bfs_add_entry(struct inode *dir, const unsigned char *name, 286 int namelen, int ino) 287 { 288 struct buffer_head *bh; 289 struct bfs_dirent *de; 290 int block, sblock, eblock, off, pos; 291 int i; 292 293 dprintf("name=%s, namelen=%d\n", name, namelen); 294 295 if (!namelen) 296 return -ENOENT; 297 if (namelen > BFS_NAMELEN) 298 return -ENAMETOOLONG; 299 300 sblock = BFS_I(dir)->i_sblock; 301 eblock = BFS_I(dir)->i_eblock; 302 for (block = sblock; block <= eblock; block++) { 303 bh = sb_bread(dir->i_sb, block); 304 if (!bh) 305 return -ENOSPC; 306 for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) { 307 de = (struct bfs_dirent *)(bh->b_data + off); 308 if (!de->ino) { 309 pos = (block - sblock) * BFS_BSIZE + off; 310 if (pos >= dir->i_size) { 311 dir->i_size += BFS_DIRENT_SIZE; 312 dir->i_ctime = CURRENT_TIME_SEC; 313 } 314 dir->i_mtime = CURRENT_TIME_SEC; 315 mark_inode_dirty(dir); 316 de->ino = cpu_to_le16((u16)ino); 317 for (i = 0; i < BFS_NAMELEN; i++) 318 de->name[i] = 319 (i < namelen) ? name[i] : 0; 320 mark_buffer_dirty_inode(bh, dir); 321 brelse(bh); 322 return 0; 323 } 324 } 325 brelse(bh); 326 } 327 return -ENOSPC; 328 } 329 330 static inline int bfs_namecmp(int len, const unsigned char *name, 331 const char *buffer) 332 { 333 if ((len < BFS_NAMELEN) && buffer[len]) 334 return 0; 335 return !memcmp(name, buffer, len); 336 } 337 338 static struct buffer_head *bfs_find_entry(struct inode *dir, 339 const unsigned char *name, int namelen, 340 struct bfs_dirent **res_dir) 341 { 342 unsigned long block = 0, offset = 0; 343 struct buffer_head *bh = NULL; 344 struct bfs_dirent *de; 345 346 *res_dir = NULL; 347 if (namelen > BFS_NAMELEN) 348 return NULL; 349 350 while (block * BFS_BSIZE + offset < dir->i_size) { 351 if (!bh) { 352 bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block); 353 if (!bh) { 354 block++; 355 continue; 356 } 357 } 358 de = (struct bfs_dirent *)(bh->b_data + offset); 359 offset += BFS_DIRENT_SIZE; 360 if (le16_to_cpu(de->ino) && 361 bfs_namecmp(namelen, name, de->name)) { 362 *res_dir = de; 363 return bh; 364 } 365 if (offset < bh->b_size) 366 continue; 367 brelse(bh); 368 bh = NULL; 369 offset = 0; 370 block++; 371 } 372 brelse(bh); 373 return NULL; 374 } 375