1 /* 2 * linux/fs/ext2/namei.c 3 * 4 * Rewrite to pagecache. Almost all code had been changed, so blame me 5 * if the things go wrong. Please, send bug reports to 6 * viro@parcelfarce.linux.theplanet.co.uk 7 * 8 * Stuff here is basically a glue between the VFS and generic UNIXish 9 * filesystem that keeps everything in pagecache. All knowledge of the 10 * directory layout is in fs/ext2/dir.c - it turned out to be easily separatable 11 * and it's easier to debug that way. In principle we might want to 12 * generalize that a bit and turn it into a library. Or not. 13 * 14 * The only non-static object here is ext2_dir_inode_operations. 15 * 16 * TODO: get rid of kmap() use, add readahead. 17 * 18 * Copyright (C) 1992, 1993, 1994, 1995 19 * Remy Card (card@masi.ibp.fr) 20 * Laboratoire MASI - Institut Blaise Pascal 21 * Universite Pierre et Marie Curie (Paris VI) 22 * 23 * from 24 * 25 * linux/fs/minix/namei.c 26 * 27 * Copyright (C) 1991, 1992 Linus Torvalds 28 * 29 * Big-endian to little-endian byte-swapping/bitmaps by 30 * David S. Miller (davem@caip.rutgers.edu), 1995 31 */ 32 33 #include <linux/pagemap.h> 34 #include <linux/quotaops.h> 35 #include "ext2.h" 36 #include "xattr.h" 37 #include "acl.h" 38 39 static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode) 40 { 41 int err = ext2_add_link(dentry, inode); 42 if (!err) { 43 unlock_new_inode(inode); 44 d_instantiate(dentry, inode); 45 return 0; 46 } 47 inode_dec_link_count(inode); 48 unlock_new_inode(inode); 49 iput(inode); 50 return err; 51 } 52 53 /* 54 * Methods themselves. 55 */ 56 57 static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags) 58 { 59 struct inode * inode; 60 ino_t ino; 61 62 if (dentry->d_name.len > EXT2_NAME_LEN) 63 return ERR_PTR(-ENAMETOOLONG); 64 65 ino = ext2_inode_by_name(dir, &dentry->d_name); 66 inode = NULL; 67 if (ino) { 68 inode = ext2_iget(dir->i_sb, ino); 69 if (inode == ERR_PTR(-ESTALE)) { 70 ext2_error(dir->i_sb, __func__, 71 "deleted inode referenced: %lu", 72 (unsigned long) ino); 73 return ERR_PTR(-EIO); 74 } 75 } 76 return d_splice_alias(inode, dentry); 77 } 78 79 struct dentry *ext2_get_parent(struct dentry *child) 80 { 81 struct qstr dotdot = QSTR_INIT("..", 2); 82 unsigned long ino = ext2_inode_by_name(d_inode(child), &dotdot); 83 if (!ino) 84 return ERR_PTR(-ENOENT); 85 return d_obtain_alias(ext2_iget(d_inode(child)->i_sb, ino)); 86 } 87 88 /* 89 * By the time this is called, we already have created 90 * the directory cache entry for the new file, but it 91 * is so far negative - it has no inode. 92 * 93 * If the create succeeds, we fill in the inode information 94 * with d_instantiate(). 95 */ 96 static int ext2_create (struct inode * dir, struct dentry * dentry, umode_t mode, bool excl) 97 { 98 struct inode *inode; 99 int err; 100 101 err = dquot_initialize(dir); 102 if (err) 103 return err; 104 105 inode = ext2_new_inode(dir, mode, &dentry->d_name); 106 if (IS_ERR(inode)) 107 return PTR_ERR(inode); 108 109 inode->i_op = &ext2_file_inode_operations; 110 if (test_opt(inode->i_sb, NOBH)) { 111 inode->i_mapping->a_ops = &ext2_nobh_aops; 112 inode->i_fop = &ext2_file_operations; 113 } else { 114 inode->i_mapping->a_ops = &ext2_aops; 115 inode->i_fop = &ext2_file_operations; 116 } 117 mark_inode_dirty(inode); 118 return ext2_add_nondir(dentry, inode); 119 } 120 121 static int ext2_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) 122 { 123 struct inode *inode = ext2_new_inode(dir, mode, NULL); 124 if (IS_ERR(inode)) 125 return PTR_ERR(inode); 126 127 inode->i_op = &ext2_file_inode_operations; 128 if (test_opt(inode->i_sb, NOBH)) { 129 inode->i_mapping->a_ops = &ext2_nobh_aops; 130 inode->i_fop = &ext2_file_operations; 131 } else { 132 inode->i_mapping->a_ops = &ext2_aops; 133 inode->i_fop = &ext2_file_operations; 134 } 135 mark_inode_dirty(inode); 136 d_tmpfile(dentry, inode); 137 unlock_new_inode(inode); 138 return 0; 139 } 140 141 static int ext2_mknod (struct inode * dir, struct dentry *dentry, umode_t mode, dev_t rdev) 142 { 143 struct inode * inode; 144 int err; 145 146 if (!new_valid_dev(rdev)) 147 return -EINVAL; 148 149 err = dquot_initialize(dir); 150 if (err) 151 return err; 152 153 inode = ext2_new_inode (dir, mode, &dentry->d_name); 154 err = PTR_ERR(inode); 155 if (!IS_ERR(inode)) { 156 init_special_inode(inode, inode->i_mode, rdev); 157 #ifdef CONFIG_EXT2_FS_XATTR 158 inode->i_op = &ext2_special_inode_operations; 159 #endif 160 mark_inode_dirty(inode); 161 err = ext2_add_nondir(dentry, inode); 162 } 163 return err; 164 } 165 166 static int ext2_symlink (struct inode * dir, struct dentry * dentry, 167 const char * symname) 168 { 169 struct super_block * sb = dir->i_sb; 170 int err = -ENAMETOOLONG; 171 unsigned l = strlen(symname)+1; 172 struct inode * inode; 173 174 if (l > sb->s_blocksize) 175 goto out; 176 177 err = dquot_initialize(dir); 178 if (err) 179 goto out; 180 181 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name); 182 err = PTR_ERR(inode); 183 if (IS_ERR(inode)) 184 goto out; 185 186 if (l > sizeof (EXT2_I(inode)->i_data)) { 187 /* slow symlink */ 188 inode->i_op = &ext2_symlink_inode_operations; 189 if (test_opt(inode->i_sb, NOBH)) 190 inode->i_mapping->a_ops = &ext2_nobh_aops; 191 else 192 inode->i_mapping->a_ops = &ext2_aops; 193 err = page_symlink(inode, symname, l); 194 if (err) 195 goto out_fail; 196 } else { 197 /* fast symlink */ 198 inode->i_op = &ext2_fast_symlink_inode_operations; 199 inode->i_link = (char*)EXT2_I(inode)->i_data; 200 memcpy(inode->i_link, symname, l); 201 inode->i_size = l-1; 202 } 203 mark_inode_dirty(inode); 204 205 err = ext2_add_nondir(dentry, inode); 206 out: 207 return err; 208 209 out_fail: 210 inode_dec_link_count(inode); 211 unlock_new_inode(inode); 212 iput (inode); 213 goto out; 214 } 215 216 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 217 struct dentry *dentry) 218 { 219 struct inode *inode = d_inode(old_dentry); 220 int err; 221 222 err = dquot_initialize(dir); 223 if (err) 224 return err; 225 226 inode->i_ctime = CURRENT_TIME_SEC; 227 inode_inc_link_count(inode); 228 ihold(inode); 229 230 err = ext2_add_link(dentry, inode); 231 if (!err) { 232 d_instantiate(dentry, inode); 233 return 0; 234 } 235 inode_dec_link_count(inode); 236 iput(inode); 237 return err; 238 } 239 240 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode) 241 { 242 struct inode * inode; 243 int err; 244 245 err = dquot_initialize(dir); 246 if (err) 247 return err; 248 249 inode_inc_link_count(dir); 250 251 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 252 err = PTR_ERR(inode); 253 if (IS_ERR(inode)) 254 goto out_dir; 255 256 inode->i_op = &ext2_dir_inode_operations; 257 inode->i_fop = &ext2_dir_operations; 258 if (test_opt(inode->i_sb, NOBH)) 259 inode->i_mapping->a_ops = &ext2_nobh_aops; 260 else 261 inode->i_mapping->a_ops = &ext2_aops; 262 263 inode_inc_link_count(inode); 264 265 err = ext2_make_empty(inode, dir); 266 if (err) 267 goto out_fail; 268 269 err = ext2_add_link(dentry, inode); 270 if (err) 271 goto out_fail; 272 273 unlock_new_inode(inode); 274 d_instantiate(dentry, inode); 275 out: 276 return err; 277 278 out_fail: 279 inode_dec_link_count(inode); 280 inode_dec_link_count(inode); 281 unlock_new_inode(inode); 282 iput(inode); 283 out_dir: 284 inode_dec_link_count(dir); 285 goto out; 286 } 287 288 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 289 { 290 struct inode * inode = d_inode(dentry); 291 struct ext2_dir_entry_2 * de; 292 struct page * page; 293 int err; 294 295 err = dquot_initialize(dir); 296 if (err) 297 goto out; 298 299 de = ext2_find_entry (dir, &dentry->d_name, &page); 300 if (!de) { 301 err = -ENOENT; 302 goto out; 303 } 304 305 err = ext2_delete_entry (de, page); 306 if (err) 307 goto out; 308 309 inode->i_ctime = dir->i_ctime; 310 inode_dec_link_count(inode); 311 err = 0; 312 out: 313 return err; 314 } 315 316 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 317 { 318 struct inode * inode = d_inode(dentry); 319 int err = -ENOTEMPTY; 320 321 if (ext2_empty_dir(inode)) { 322 err = ext2_unlink(dir, dentry); 323 if (!err) { 324 inode->i_size = 0; 325 inode_dec_link_count(inode); 326 inode_dec_link_count(dir); 327 } 328 } 329 return err; 330 } 331 332 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 333 struct inode * new_dir, struct dentry * new_dentry ) 334 { 335 struct inode * old_inode = d_inode(old_dentry); 336 struct inode * new_inode = d_inode(new_dentry); 337 struct page * dir_page = NULL; 338 struct ext2_dir_entry_2 * dir_de = NULL; 339 struct page * old_page; 340 struct ext2_dir_entry_2 * old_de; 341 int err; 342 343 err = dquot_initialize(old_dir); 344 if (err) 345 goto out; 346 347 err = dquot_initialize(new_dir); 348 if (err) 349 goto out; 350 351 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page); 352 if (!old_de) { 353 err = -ENOENT; 354 goto out; 355 } 356 357 if (S_ISDIR(old_inode->i_mode)) { 358 err = -EIO; 359 dir_de = ext2_dotdot(old_inode, &dir_page); 360 if (!dir_de) 361 goto out_old; 362 } 363 364 if (new_inode) { 365 struct page *new_page; 366 struct ext2_dir_entry_2 *new_de; 367 368 err = -ENOTEMPTY; 369 if (dir_de && !ext2_empty_dir (new_inode)) 370 goto out_dir; 371 372 err = -ENOENT; 373 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page); 374 if (!new_de) 375 goto out_dir; 376 ext2_set_link(new_dir, new_de, new_page, old_inode, 1); 377 new_inode->i_ctime = CURRENT_TIME_SEC; 378 if (dir_de) 379 drop_nlink(new_inode); 380 inode_dec_link_count(new_inode); 381 } else { 382 err = ext2_add_link(new_dentry, old_inode); 383 if (err) 384 goto out_dir; 385 if (dir_de) 386 inode_inc_link_count(new_dir); 387 } 388 389 /* 390 * Like most other Unix systems, set the ctime for inodes on a 391 * rename. 392 */ 393 old_inode->i_ctime = CURRENT_TIME_SEC; 394 mark_inode_dirty(old_inode); 395 396 ext2_delete_entry (old_de, old_page); 397 398 if (dir_de) { 399 if (old_dir != new_dir) 400 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0); 401 else { 402 kunmap(dir_page); 403 page_cache_release(dir_page); 404 } 405 inode_dec_link_count(old_dir); 406 } 407 return 0; 408 409 410 out_dir: 411 if (dir_de) { 412 kunmap(dir_page); 413 page_cache_release(dir_page); 414 } 415 out_old: 416 kunmap(old_page); 417 page_cache_release(old_page); 418 out: 419 return err; 420 } 421 422 const struct inode_operations ext2_dir_inode_operations = { 423 .create = ext2_create, 424 .lookup = ext2_lookup, 425 .link = ext2_link, 426 .unlink = ext2_unlink, 427 .symlink = ext2_symlink, 428 .mkdir = ext2_mkdir, 429 .rmdir = ext2_rmdir, 430 .mknod = ext2_mknod, 431 .rename = ext2_rename, 432 #ifdef CONFIG_EXT2_FS_XATTR 433 .setxattr = generic_setxattr, 434 .getxattr = generic_getxattr, 435 .listxattr = ext2_listxattr, 436 .removexattr = generic_removexattr, 437 #endif 438 .setattr = ext2_setattr, 439 .get_acl = ext2_get_acl, 440 .set_acl = ext2_set_acl, 441 .tmpfile = ext2_tmpfile, 442 }; 443 444 const struct inode_operations ext2_special_inode_operations = { 445 #ifdef CONFIG_EXT2_FS_XATTR 446 .setxattr = generic_setxattr, 447 .getxattr = generic_getxattr, 448 .listxattr = ext2_listxattr, 449 .removexattr = generic_removexattr, 450 #endif 451 .setattr = ext2_setattr, 452 .get_acl = ext2_get_acl, 453 .set_acl = ext2_set_acl, 454 }; 455