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 inode_nohighmem(inode); 187 if (test_opt(inode->i_sb, NOBH)) 188 inode->i_mapping->a_ops = &ext2_nobh_aops; 189 else 190 inode->i_mapping->a_ops = &ext2_aops; 191 err = page_symlink(inode, symname, l); 192 if (err) 193 goto out_fail; 194 } else { 195 /* fast symlink */ 196 inode->i_op = &ext2_fast_symlink_inode_operations; 197 inode->i_link = (char*)EXT2_I(inode)->i_data; 198 memcpy(inode->i_link, symname, l); 199 inode->i_size = l-1; 200 } 201 mark_inode_dirty(inode); 202 203 err = ext2_add_nondir(dentry, inode); 204 out: 205 return err; 206 207 out_fail: 208 inode_dec_link_count(inode); 209 unlock_new_inode(inode); 210 iput (inode); 211 goto out; 212 } 213 214 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 215 struct dentry *dentry) 216 { 217 struct inode *inode = d_inode(old_dentry); 218 int err; 219 220 err = dquot_initialize(dir); 221 if (err) 222 return err; 223 224 inode->i_ctime = CURRENT_TIME_SEC; 225 inode_inc_link_count(inode); 226 ihold(inode); 227 228 err = ext2_add_link(dentry, inode); 229 if (!err) { 230 d_instantiate(dentry, inode); 231 return 0; 232 } 233 inode_dec_link_count(inode); 234 iput(inode); 235 return err; 236 } 237 238 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode) 239 { 240 struct inode * inode; 241 int err; 242 243 err = dquot_initialize(dir); 244 if (err) 245 return err; 246 247 inode_inc_link_count(dir); 248 249 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 250 err = PTR_ERR(inode); 251 if (IS_ERR(inode)) 252 goto out_dir; 253 254 inode->i_op = &ext2_dir_inode_operations; 255 inode->i_fop = &ext2_dir_operations; 256 if (test_opt(inode->i_sb, NOBH)) 257 inode->i_mapping->a_ops = &ext2_nobh_aops; 258 else 259 inode->i_mapping->a_ops = &ext2_aops; 260 261 inode_inc_link_count(inode); 262 263 err = ext2_make_empty(inode, dir); 264 if (err) 265 goto out_fail; 266 267 err = ext2_add_link(dentry, inode); 268 if (err) 269 goto out_fail; 270 271 unlock_new_inode(inode); 272 d_instantiate(dentry, inode); 273 out: 274 return err; 275 276 out_fail: 277 inode_dec_link_count(inode); 278 inode_dec_link_count(inode); 279 unlock_new_inode(inode); 280 iput(inode); 281 out_dir: 282 inode_dec_link_count(dir); 283 goto out; 284 } 285 286 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 287 { 288 struct inode * inode = d_inode(dentry); 289 struct ext2_dir_entry_2 * de; 290 struct page * page; 291 int err; 292 293 err = dquot_initialize(dir); 294 if (err) 295 goto out; 296 297 de = ext2_find_entry (dir, &dentry->d_name, &page); 298 if (!de) { 299 err = -ENOENT; 300 goto out; 301 } 302 303 err = ext2_delete_entry (de, page); 304 if (err) 305 goto out; 306 307 inode->i_ctime = dir->i_ctime; 308 inode_dec_link_count(inode); 309 err = 0; 310 out: 311 return err; 312 } 313 314 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 315 { 316 struct inode * inode = d_inode(dentry); 317 int err = -ENOTEMPTY; 318 319 if (ext2_empty_dir(inode)) { 320 err = ext2_unlink(dir, dentry); 321 if (!err) { 322 inode->i_size = 0; 323 inode_dec_link_count(inode); 324 inode_dec_link_count(dir); 325 } 326 } 327 return err; 328 } 329 330 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 331 struct inode * new_dir, struct dentry * new_dentry ) 332 { 333 struct inode * old_inode = d_inode(old_dentry); 334 struct inode * new_inode = d_inode(new_dentry); 335 struct page * dir_page = NULL; 336 struct ext2_dir_entry_2 * dir_de = NULL; 337 struct page * old_page; 338 struct ext2_dir_entry_2 * old_de; 339 int err; 340 341 err = dquot_initialize(old_dir); 342 if (err) 343 goto out; 344 345 err = dquot_initialize(new_dir); 346 if (err) 347 goto out; 348 349 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page); 350 if (!old_de) { 351 err = -ENOENT; 352 goto out; 353 } 354 355 if (S_ISDIR(old_inode->i_mode)) { 356 err = -EIO; 357 dir_de = ext2_dotdot(old_inode, &dir_page); 358 if (!dir_de) 359 goto out_old; 360 } 361 362 if (new_inode) { 363 struct page *new_page; 364 struct ext2_dir_entry_2 *new_de; 365 366 err = -ENOTEMPTY; 367 if (dir_de && !ext2_empty_dir (new_inode)) 368 goto out_dir; 369 370 err = -ENOENT; 371 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page); 372 if (!new_de) 373 goto out_dir; 374 ext2_set_link(new_dir, new_de, new_page, old_inode, 1); 375 new_inode->i_ctime = CURRENT_TIME_SEC; 376 if (dir_de) 377 drop_nlink(new_inode); 378 inode_dec_link_count(new_inode); 379 } else { 380 err = ext2_add_link(new_dentry, old_inode); 381 if (err) 382 goto out_dir; 383 if (dir_de) 384 inode_inc_link_count(new_dir); 385 } 386 387 /* 388 * Like most other Unix systems, set the ctime for inodes on a 389 * rename. 390 */ 391 old_inode->i_ctime = CURRENT_TIME_SEC; 392 mark_inode_dirty(old_inode); 393 394 ext2_delete_entry (old_de, old_page); 395 396 if (dir_de) { 397 if (old_dir != new_dir) 398 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0); 399 else { 400 kunmap(dir_page); 401 page_cache_release(dir_page); 402 } 403 inode_dec_link_count(old_dir); 404 } 405 return 0; 406 407 408 out_dir: 409 if (dir_de) { 410 kunmap(dir_page); 411 page_cache_release(dir_page); 412 } 413 out_old: 414 kunmap(old_page); 415 page_cache_release(old_page); 416 out: 417 return err; 418 } 419 420 const struct inode_operations ext2_dir_inode_operations = { 421 .create = ext2_create, 422 .lookup = ext2_lookup, 423 .link = ext2_link, 424 .unlink = ext2_unlink, 425 .symlink = ext2_symlink, 426 .mkdir = ext2_mkdir, 427 .rmdir = ext2_rmdir, 428 .mknod = ext2_mknod, 429 .rename = ext2_rename, 430 #ifdef CONFIG_EXT2_FS_XATTR 431 .setxattr = generic_setxattr, 432 .getxattr = generic_getxattr, 433 .listxattr = ext2_listxattr, 434 .removexattr = generic_removexattr, 435 #endif 436 .setattr = ext2_setattr, 437 .get_acl = ext2_get_acl, 438 .set_acl = ext2_set_acl, 439 .tmpfile = ext2_tmpfile, 440 }; 441 442 const struct inode_operations ext2_special_inode_operations = { 443 #ifdef CONFIG_EXT2_FS_XATTR 444 .setxattr = generic_setxattr, 445 .getxattr = generic_getxattr, 446 .listxattr = ext2_listxattr, 447 .removexattr = generic_removexattr, 448 #endif 449 .setattr = ext2_setattr, 450 .get_acl = ext2_get_acl, 451 .set_acl = ext2_set_acl, 452 }; 453