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/smp_lock.h> 12 #include <linux/buffer_head.h> 13 #include <linux/sched.h> 14 #include "bfs.h" 15 16 #undef DEBUG 17 18 #ifdef DEBUG 19 #define dprintf(x...) printf(x) 20 #else 21 #define dprintf(x...) 22 #endif 23 24 static int bfs_add_entry(struct inode *dir, const unsigned char *name, 25 int namelen, int ino); 26 static struct buffer_head *bfs_find_entry(struct inode *dir, 27 const unsigned char *name, int namelen, 28 struct bfs_dirent **res_dir); 29 30 static int bfs_readdir(struct file *f, void *dirent, filldir_t filldir) 31 { 32 struct inode *dir = f->f_path.dentry->d_inode; 33 struct buffer_head *bh; 34 struct bfs_dirent *de; 35 unsigned int offset; 36 int block; 37 38 lock_kernel(); 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 unlock_kernel(); 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 unlock_kernel(); 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 unlock_kernel(); 75 return 0; 76 } 77 78 const struct file_operations bfs_dir_operations = { 79 .read = generic_read_dir, 80 .readdir = bfs_readdir, 81 .fsync = file_fsync, 82 }; 83 84 extern void dump_imap(const char *, struct super_block *); 85 86 static int bfs_create(struct inode *dir, struct dentry *dentry, int mode, 87 struct nameidata *nd) 88 { 89 int err; 90 struct inode *inode; 91 struct super_block *s = dir->i_sb; 92 struct bfs_sb_info *info = BFS_SB(s); 93 unsigned long ino; 94 95 inode = new_inode(s); 96 if (!inode) 97 return -ENOSPC; 98 lock_kernel(); 99 ino = find_first_zero_bit(info->si_imap, info->si_lasti); 100 if (ino > info->si_lasti) { 101 unlock_kernel(); 102 iput(inode); 103 return -ENOSPC; 104 } 105 set_bit(ino, info->si_imap); 106 info->si_freei--; 107 inode->i_uid = current->fsuid; 108 inode->i_gid = (dir->i_mode & S_ISGID) ? dir->i_gid : current->fsgid; 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_mode = mode; 115 inode->i_ino = ino; 116 BFS_I(inode)->i_dsk_ino = ino; 117 BFS_I(inode)->i_sblock = 0; 118 BFS_I(inode)->i_eblock = 0; 119 insert_inode_hash(inode); 120 mark_inode_dirty(inode); 121 dump_imap("create", s); 122 123 err = bfs_add_entry(dir, dentry->d_name.name, dentry->d_name.len, 124 inode->i_ino); 125 if (err) { 126 inode_dec_link_count(inode); 127 iput(inode); 128 unlock_kernel(); 129 return err; 130 } 131 unlock_kernel(); 132 d_instantiate(dentry, inode); 133 return 0; 134 } 135 136 static struct dentry *bfs_lookup(struct inode *dir, struct dentry *dentry, 137 struct nameidata *nd) 138 { 139 struct inode *inode = NULL; 140 struct buffer_head *bh; 141 struct bfs_dirent *de; 142 143 if (dentry->d_name.len > BFS_NAMELEN) 144 return ERR_PTR(-ENAMETOOLONG); 145 146 lock_kernel(); 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 unlock_kernel(); 154 return ERR_CAST(inode); 155 } 156 } 157 unlock_kernel(); 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 int err; 167 168 lock_kernel(); 169 err = bfs_add_entry(dir, new->d_name.name, new->d_name.len, 170 inode->i_ino); 171 if (err) { 172 unlock_kernel(); 173 return err; 174 } 175 inc_nlink(inode); 176 inode->i_ctime = CURRENT_TIME_SEC; 177 mark_inode_dirty(inode); 178 atomic_inc(&inode->i_count); 179 d_instantiate(new, inode); 180 unlock_kernel(); 181 return 0; 182 } 183 184 static int bfs_unlink(struct inode *dir, struct dentry *dentry) 185 { 186 int error = -ENOENT; 187 struct inode *inode; 188 struct buffer_head *bh; 189 struct bfs_dirent *de; 190 191 inode = dentry->d_inode; 192 lock_kernel(); 193 bh = bfs_find_entry(dir, dentry->d_name.name, dentry->d_name.len, &de); 194 if (!bh || (le16_to_cpu(de->ino) != inode->i_ino)) 195 goto out_brelse; 196 197 if (!inode->i_nlink) { 198 printf("unlinking non-existent file %s:%lu (nlink=%d)\n", 199 inode->i_sb->s_id, inode->i_ino, 200 inode->i_nlink); 201 inode->i_nlink = 1; 202 } 203 de->ino = 0; 204 mark_buffer_dirty(bh); 205 dir->i_ctime = dir->i_mtime = CURRENT_TIME_SEC; 206 mark_inode_dirty(dir); 207 inode->i_ctime = dir->i_ctime; 208 inode_dec_link_count(inode); 209 error = 0; 210 211 out_brelse: 212 brelse(bh); 213 unlock_kernel(); 214 return error; 215 } 216 217 static int bfs_rename(struct inode *old_dir, struct dentry *old_dentry, 218 struct inode *new_dir, struct dentry *new_dentry) 219 { 220 struct inode *old_inode, *new_inode; 221 struct buffer_head *old_bh, *new_bh; 222 struct bfs_dirent *old_de, *new_de; 223 int error = -ENOENT; 224 225 old_bh = new_bh = NULL; 226 old_inode = old_dentry->d_inode; 227 if (S_ISDIR(old_inode->i_mode)) 228 return -EINVAL; 229 230 lock_kernel(); 231 old_bh = bfs_find_entry(old_dir, 232 old_dentry->d_name.name, 233 old_dentry->d_name.len, &old_de); 234 235 if (!old_bh || (le16_to_cpu(old_de->ino) != old_inode->i_ino)) 236 goto end_rename; 237 238 error = -EPERM; 239 new_inode = new_dentry->d_inode; 240 new_bh = bfs_find_entry(new_dir, 241 new_dentry->d_name.name, 242 new_dentry->d_name.len, &new_de); 243 244 if (new_bh && !new_inode) { 245 brelse(new_bh); 246 new_bh = NULL; 247 } 248 if (!new_bh) { 249 error = bfs_add_entry(new_dir, 250 new_dentry->d_name.name, 251 new_dentry->d_name.len, 252 old_inode->i_ino); 253 if (error) 254 goto end_rename; 255 } 256 old_de->ino = 0; 257 old_dir->i_ctime = old_dir->i_mtime = CURRENT_TIME_SEC; 258 mark_inode_dirty(old_dir); 259 if (new_inode) { 260 new_inode->i_ctime = CURRENT_TIME_SEC; 261 inode_dec_link_count(new_inode); 262 } 263 mark_buffer_dirty(old_bh); 264 error = 0; 265 266 end_rename: 267 unlock_kernel(); 268 brelse(old_bh); 269 brelse(new_bh); 270 return error; 271 } 272 273 const struct inode_operations bfs_dir_inops = { 274 .create = bfs_create, 275 .lookup = bfs_lookup, 276 .link = bfs_link, 277 .unlink = bfs_unlink, 278 .rename = bfs_rename, 279 }; 280 281 static int bfs_add_entry(struct inode *dir, const unsigned char *name, 282 int namelen, int ino) 283 { 284 struct buffer_head *bh; 285 struct bfs_dirent *de; 286 int block, sblock, eblock, off, pos; 287 int i; 288 289 dprintf("name=%s, namelen=%d\n", name, namelen); 290 291 if (!namelen) 292 return -ENOENT; 293 if (namelen > BFS_NAMELEN) 294 return -ENAMETOOLONG; 295 296 sblock = BFS_I(dir)->i_sblock; 297 eblock = BFS_I(dir)->i_eblock; 298 for (block = sblock; block <= eblock; block++) { 299 bh = sb_bread(dir->i_sb, block); 300 if (!bh) 301 return -ENOSPC; 302 for (off = 0; off < BFS_BSIZE; off += BFS_DIRENT_SIZE) { 303 de = (struct bfs_dirent *)(bh->b_data + off); 304 if (!de->ino) { 305 pos = (block - sblock) * BFS_BSIZE + off; 306 if (pos >= dir->i_size) { 307 dir->i_size += BFS_DIRENT_SIZE; 308 dir->i_ctime = CURRENT_TIME_SEC; 309 } 310 dir->i_mtime = CURRENT_TIME_SEC; 311 mark_inode_dirty(dir); 312 de->ino = cpu_to_le16((u16)ino); 313 for (i = 0; i < BFS_NAMELEN; i++) 314 de->name[i] = 315 (i < namelen) ? name[i] : 0; 316 mark_buffer_dirty(bh); 317 brelse(bh); 318 return 0; 319 } 320 } 321 brelse(bh); 322 } 323 return -ENOSPC; 324 } 325 326 static inline int bfs_namecmp(int len, const unsigned char *name, 327 const char *buffer) 328 { 329 if ((len < BFS_NAMELEN) && buffer[len]) 330 return 0; 331 return !memcmp(name, buffer, len); 332 } 333 334 static struct buffer_head *bfs_find_entry(struct inode *dir, 335 const unsigned char *name, int namelen, 336 struct bfs_dirent **res_dir) 337 { 338 unsigned long block = 0, offset = 0; 339 struct buffer_head *bh = NULL; 340 struct bfs_dirent *de; 341 342 *res_dir = NULL; 343 if (namelen > BFS_NAMELEN) 344 return NULL; 345 346 while (block * BFS_BSIZE + offset < dir->i_size) { 347 if (!bh) { 348 bh = sb_bread(dir->i_sb, BFS_I(dir)->i_sblock + block); 349 if (!bh) { 350 block++; 351 continue; 352 } 353 } 354 de = (struct bfs_dirent *)(bh->b_data + offset); 355 offset += BFS_DIRENT_SIZE; 356 if (le16_to_cpu(de->ino) && 357 bfs_namecmp(namelen, name, de->name)) { 358 *res_dir = de; 359 return bh; 360 } 361 if (offset < bh->b_size) 362 continue; 363 brelse(bh); 364 bh = NULL; 365 offset = 0; 366 block++; 367 } 368 brelse(bh); 369 return NULL; 370 } 371