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 err = dquot_initialize(dir); 147 if (err) 148 return err; 149 150 inode = ext2_new_inode (dir, mode, &dentry->d_name); 151 err = PTR_ERR(inode); 152 if (!IS_ERR(inode)) { 153 init_special_inode(inode, inode->i_mode, rdev); 154 #ifdef CONFIG_EXT2_FS_XATTR 155 inode->i_op = &ext2_special_inode_operations; 156 #endif 157 mark_inode_dirty(inode); 158 err = ext2_add_nondir(dentry, inode); 159 } 160 return err; 161 } 162 163 static int ext2_symlink (struct inode * dir, struct dentry * dentry, 164 const char * symname) 165 { 166 struct super_block * sb = dir->i_sb; 167 int err = -ENAMETOOLONG; 168 unsigned l = strlen(symname)+1; 169 struct inode * inode; 170 171 if (l > sb->s_blocksize) 172 goto out; 173 174 err = dquot_initialize(dir); 175 if (err) 176 goto out; 177 178 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name); 179 err = PTR_ERR(inode); 180 if (IS_ERR(inode)) 181 goto out; 182 183 if (l > sizeof (EXT2_I(inode)->i_data)) { 184 /* slow symlink */ 185 inode->i_op = &ext2_symlink_inode_operations; 186 if (test_opt(inode->i_sb, NOBH)) 187 inode->i_mapping->a_ops = &ext2_nobh_aops; 188 else 189 inode->i_mapping->a_ops = &ext2_aops; 190 err = page_symlink(inode, symname, l); 191 if (err) 192 goto out_fail; 193 } else { 194 /* fast symlink */ 195 inode->i_op = &ext2_fast_symlink_inode_operations; 196 inode->i_link = (char*)EXT2_I(inode)->i_data; 197 memcpy(inode->i_link, symname, l); 198 inode->i_size = l-1; 199 } 200 mark_inode_dirty(inode); 201 202 err = ext2_add_nondir(dentry, inode); 203 out: 204 return err; 205 206 out_fail: 207 inode_dec_link_count(inode); 208 unlock_new_inode(inode); 209 iput (inode); 210 goto out; 211 } 212 213 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 214 struct dentry *dentry) 215 { 216 struct inode *inode = d_inode(old_dentry); 217 int err; 218 219 err = dquot_initialize(dir); 220 if (err) 221 return err; 222 223 inode->i_ctime = CURRENT_TIME_SEC; 224 inode_inc_link_count(inode); 225 ihold(inode); 226 227 err = ext2_add_link(dentry, inode); 228 if (!err) { 229 d_instantiate(dentry, inode); 230 return 0; 231 } 232 inode_dec_link_count(inode); 233 iput(inode); 234 return err; 235 } 236 237 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode) 238 { 239 struct inode * inode; 240 int err; 241 242 err = dquot_initialize(dir); 243 if (err) 244 return err; 245 246 inode_inc_link_count(dir); 247 248 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 249 err = PTR_ERR(inode); 250 if (IS_ERR(inode)) 251 goto out_dir; 252 253 inode->i_op = &ext2_dir_inode_operations; 254 inode->i_fop = &ext2_dir_operations; 255 if (test_opt(inode->i_sb, NOBH)) 256 inode->i_mapping->a_ops = &ext2_nobh_aops; 257 else 258 inode->i_mapping->a_ops = &ext2_aops; 259 260 inode_inc_link_count(inode); 261 262 err = ext2_make_empty(inode, dir); 263 if (err) 264 goto out_fail; 265 266 err = ext2_add_link(dentry, inode); 267 if (err) 268 goto out_fail; 269 270 unlock_new_inode(inode); 271 d_instantiate(dentry, inode); 272 out: 273 return err; 274 275 out_fail: 276 inode_dec_link_count(inode); 277 inode_dec_link_count(inode); 278 unlock_new_inode(inode); 279 iput(inode); 280 out_dir: 281 inode_dec_link_count(dir); 282 goto out; 283 } 284 285 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 286 { 287 struct inode * inode = d_inode(dentry); 288 struct ext2_dir_entry_2 * de; 289 struct page * page; 290 int err; 291 292 err = dquot_initialize(dir); 293 if (err) 294 goto out; 295 296 de = ext2_find_entry (dir, &dentry->d_name, &page); 297 if (!de) { 298 err = -ENOENT; 299 goto out; 300 } 301 302 err = ext2_delete_entry (de, page); 303 if (err) 304 goto out; 305 306 inode->i_ctime = dir->i_ctime; 307 inode_dec_link_count(inode); 308 err = 0; 309 out: 310 return err; 311 } 312 313 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 314 { 315 struct inode * inode = d_inode(dentry); 316 int err = -ENOTEMPTY; 317 318 if (ext2_empty_dir(inode)) { 319 err = ext2_unlink(dir, dentry); 320 if (!err) { 321 inode->i_size = 0; 322 inode_dec_link_count(inode); 323 inode_dec_link_count(dir); 324 } 325 } 326 return err; 327 } 328 329 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 330 struct inode * new_dir, struct dentry * new_dentry ) 331 { 332 struct inode * old_inode = d_inode(old_dentry); 333 struct inode * new_inode = d_inode(new_dentry); 334 struct page * dir_page = NULL; 335 struct ext2_dir_entry_2 * dir_de = NULL; 336 struct page * old_page; 337 struct ext2_dir_entry_2 * old_de; 338 int err; 339 340 err = dquot_initialize(old_dir); 341 if (err) 342 goto out; 343 344 err = dquot_initialize(new_dir); 345 if (err) 346 goto out; 347 348 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page); 349 if (!old_de) { 350 err = -ENOENT; 351 goto out; 352 } 353 354 if (S_ISDIR(old_inode->i_mode)) { 355 err = -EIO; 356 dir_de = ext2_dotdot(old_inode, &dir_page); 357 if (!dir_de) 358 goto out_old; 359 } 360 361 if (new_inode) { 362 struct page *new_page; 363 struct ext2_dir_entry_2 *new_de; 364 365 err = -ENOTEMPTY; 366 if (dir_de && !ext2_empty_dir (new_inode)) 367 goto out_dir; 368 369 err = -ENOENT; 370 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page); 371 if (!new_de) 372 goto out_dir; 373 ext2_set_link(new_dir, new_de, new_page, old_inode, 1); 374 new_inode->i_ctime = CURRENT_TIME_SEC; 375 if (dir_de) 376 drop_nlink(new_inode); 377 inode_dec_link_count(new_inode); 378 } else { 379 err = ext2_add_link(new_dentry, old_inode); 380 if (err) 381 goto out_dir; 382 if (dir_de) 383 inode_inc_link_count(new_dir); 384 } 385 386 /* 387 * Like most other Unix systems, set the ctime for inodes on a 388 * rename. 389 */ 390 old_inode->i_ctime = CURRENT_TIME_SEC; 391 mark_inode_dirty(old_inode); 392 393 ext2_delete_entry (old_de, old_page); 394 395 if (dir_de) { 396 if (old_dir != new_dir) 397 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0); 398 else { 399 kunmap(dir_page); 400 page_cache_release(dir_page); 401 } 402 inode_dec_link_count(old_dir); 403 } 404 return 0; 405 406 407 out_dir: 408 if (dir_de) { 409 kunmap(dir_page); 410 page_cache_release(dir_page); 411 } 412 out_old: 413 kunmap(old_page); 414 page_cache_release(old_page); 415 out: 416 return err; 417 } 418 419 const struct inode_operations ext2_dir_inode_operations = { 420 .create = ext2_create, 421 .lookup = ext2_lookup, 422 .link = ext2_link, 423 .unlink = ext2_unlink, 424 .symlink = ext2_symlink, 425 .mkdir = ext2_mkdir, 426 .rmdir = ext2_rmdir, 427 .mknod = ext2_mknod, 428 .rename = ext2_rename, 429 #ifdef CONFIG_EXT2_FS_XATTR 430 .setxattr = generic_setxattr, 431 .getxattr = generic_getxattr, 432 .listxattr = ext2_listxattr, 433 .removexattr = generic_removexattr, 434 #endif 435 .setattr = ext2_setattr, 436 .get_acl = ext2_get_acl, 437 .set_acl = ext2_set_acl, 438 .tmpfile = ext2_tmpfile, 439 }; 440 441 const struct inode_operations ext2_special_inode_operations = { 442 #ifdef CONFIG_EXT2_FS_XATTR 443 .setxattr = generic_setxattr, 444 .getxattr = generic_getxattr, 445 .listxattr = ext2_listxattr, 446 .removexattr = generic_removexattr, 447 #endif 448 .setattr = ext2_setattr, 449 .get_acl = ext2_get_acl, 450 .set_acl = ext2_set_acl, 451 }; 452