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(child->d_inode, &dotdot); 83 if (!ino) 84 return ERR_PTR(-ENOENT); 85 return d_obtain_alias(ext2_iget(child->d_inode->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; 99 100 dquot_initialize(dir); 101 102 inode = ext2_new_inode(dir, mode, &dentry->d_name); 103 if (IS_ERR(inode)) 104 return PTR_ERR(inode); 105 106 inode->i_op = &ext2_file_inode_operations; 107 if (test_opt(inode->i_sb, DAX)) { 108 inode->i_mapping->a_ops = &ext2_aops; 109 inode->i_fop = &ext2_dax_file_operations; 110 } else 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, DAX)) { 129 inode->i_mapping->a_ops = &ext2_aops; 130 inode->i_fop = &ext2_dax_file_operations; 131 } else if (test_opt(inode->i_sb, NOBH)) { 132 inode->i_mapping->a_ops = &ext2_nobh_aops; 133 inode->i_fop = &ext2_file_operations; 134 } else { 135 inode->i_mapping->a_ops = &ext2_aops; 136 inode->i_fop = &ext2_file_operations; 137 } 138 mark_inode_dirty(inode); 139 d_tmpfile(dentry, inode); 140 unlock_new_inode(inode); 141 return 0; 142 } 143 144 static int ext2_mknod (struct inode * dir, struct dentry *dentry, umode_t mode, dev_t rdev) 145 { 146 struct inode * inode; 147 int err; 148 149 if (!new_valid_dev(rdev)) 150 return -EINVAL; 151 152 dquot_initialize(dir); 153 154 inode = ext2_new_inode (dir, mode, &dentry->d_name); 155 err = PTR_ERR(inode); 156 if (!IS_ERR(inode)) { 157 init_special_inode(inode, inode->i_mode, rdev); 158 #ifdef CONFIG_EXT2_FS_XATTR 159 inode->i_op = &ext2_special_inode_operations; 160 #endif 161 mark_inode_dirty(inode); 162 err = ext2_add_nondir(dentry, inode); 163 } 164 return err; 165 } 166 167 static int ext2_symlink (struct inode * dir, struct dentry * dentry, 168 const char * symname) 169 { 170 struct super_block * sb = dir->i_sb; 171 int err = -ENAMETOOLONG; 172 unsigned l = strlen(symname)+1; 173 struct inode * inode; 174 175 if (l > sb->s_blocksize) 176 goto out; 177 178 dquot_initialize(dir); 179 180 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name); 181 err = PTR_ERR(inode); 182 if (IS_ERR(inode)) 183 goto out; 184 185 if (l > sizeof (EXT2_I(inode)->i_data)) { 186 /* slow symlink */ 187 inode->i_op = &ext2_symlink_inode_operations; 188 if (test_opt(inode->i_sb, NOBH)) 189 inode->i_mapping->a_ops = &ext2_nobh_aops; 190 else 191 inode->i_mapping->a_ops = &ext2_aops; 192 err = page_symlink(inode, symname, l); 193 if (err) 194 goto out_fail; 195 } else { 196 /* fast symlink */ 197 inode->i_op = &ext2_fast_symlink_inode_operations; 198 memcpy((char*)(EXT2_I(inode)->i_data),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 = old_dentry->d_inode; 218 int err; 219 220 dquot_initialize(dir); 221 222 inode->i_ctime = CURRENT_TIME_SEC; 223 inode_inc_link_count(inode); 224 ihold(inode); 225 226 err = ext2_add_link(dentry, inode); 227 if (!err) { 228 d_instantiate(dentry, inode); 229 return 0; 230 } 231 inode_dec_link_count(inode); 232 iput(inode); 233 return err; 234 } 235 236 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode) 237 { 238 struct inode * inode; 239 int err; 240 241 dquot_initialize(dir); 242 243 inode_inc_link_count(dir); 244 245 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 246 err = PTR_ERR(inode); 247 if (IS_ERR(inode)) 248 goto out_dir; 249 250 inode->i_op = &ext2_dir_inode_operations; 251 inode->i_fop = &ext2_dir_operations; 252 if (test_opt(inode->i_sb, NOBH)) 253 inode->i_mapping->a_ops = &ext2_nobh_aops; 254 else 255 inode->i_mapping->a_ops = &ext2_aops; 256 257 inode_inc_link_count(inode); 258 259 err = ext2_make_empty(inode, dir); 260 if (err) 261 goto out_fail; 262 263 err = ext2_add_link(dentry, inode); 264 if (err) 265 goto out_fail; 266 267 unlock_new_inode(inode); 268 d_instantiate(dentry, inode); 269 out: 270 return err; 271 272 out_fail: 273 inode_dec_link_count(inode); 274 inode_dec_link_count(inode); 275 unlock_new_inode(inode); 276 iput(inode); 277 out_dir: 278 inode_dec_link_count(dir); 279 goto out; 280 } 281 282 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 283 { 284 struct inode * inode = dentry->d_inode; 285 struct ext2_dir_entry_2 * de; 286 struct page * page; 287 int err = -ENOENT; 288 289 dquot_initialize(dir); 290 291 de = ext2_find_entry (dir, &dentry->d_name, &page); 292 if (!de) 293 goto out; 294 295 err = ext2_delete_entry (de, page); 296 if (err) 297 goto out; 298 299 inode->i_ctime = dir->i_ctime; 300 inode_dec_link_count(inode); 301 err = 0; 302 out: 303 return err; 304 } 305 306 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 307 { 308 struct inode * inode = dentry->d_inode; 309 int err = -ENOTEMPTY; 310 311 if (ext2_empty_dir(inode)) { 312 err = ext2_unlink(dir, dentry); 313 if (!err) { 314 inode->i_size = 0; 315 inode_dec_link_count(inode); 316 inode_dec_link_count(dir); 317 } 318 } 319 return err; 320 } 321 322 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 323 struct inode * new_dir, struct dentry * new_dentry ) 324 { 325 struct inode * old_inode = old_dentry->d_inode; 326 struct inode * new_inode = new_dentry->d_inode; 327 struct page * dir_page = NULL; 328 struct ext2_dir_entry_2 * dir_de = NULL; 329 struct page * old_page; 330 struct ext2_dir_entry_2 * old_de; 331 int err = -ENOENT; 332 333 dquot_initialize(old_dir); 334 dquot_initialize(new_dir); 335 336 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page); 337 if (!old_de) 338 goto out; 339 340 if (S_ISDIR(old_inode->i_mode)) { 341 err = -EIO; 342 dir_de = ext2_dotdot(old_inode, &dir_page); 343 if (!dir_de) 344 goto out_old; 345 } 346 347 if (new_inode) { 348 struct page *new_page; 349 struct ext2_dir_entry_2 *new_de; 350 351 err = -ENOTEMPTY; 352 if (dir_de && !ext2_empty_dir (new_inode)) 353 goto out_dir; 354 355 err = -ENOENT; 356 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page); 357 if (!new_de) 358 goto out_dir; 359 ext2_set_link(new_dir, new_de, new_page, old_inode, 1); 360 new_inode->i_ctime = CURRENT_TIME_SEC; 361 if (dir_de) 362 drop_nlink(new_inode); 363 inode_dec_link_count(new_inode); 364 } else { 365 err = ext2_add_link(new_dentry, old_inode); 366 if (err) 367 goto out_dir; 368 if (dir_de) 369 inode_inc_link_count(new_dir); 370 } 371 372 /* 373 * Like most other Unix systems, set the ctime for inodes on a 374 * rename. 375 */ 376 old_inode->i_ctime = CURRENT_TIME_SEC; 377 mark_inode_dirty(old_inode); 378 379 ext2_delete_entry (old_de, old_page); 380 381 if (dir_de) { 382 if (old_dir != new_dir) 383 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0); 384 else { 385 kunmap(dir_page); 386 page_cache_release(dir_page); 387 } 388 inode_dec_link_count(old_dir); 389 } 390 return 0; 391 392 393 out_dir: 394 if (dir_de) { 395 kunmap(dir_page); 396 page_cache_release(dir_page); 397 } 398 out_old: 399 kunmap(old_page); 400 page_cache_release(old_page); 401 out: 402 return err; 403 } 404 405 const struct inode_operations ext2_dir_inode_operations = { 406 .create = ext2_create, 407 .lookup = ext2_lookup, 408 .link = ext2_link, 409 .unlink = ext2_unlink, 410 .symlink = ext2_symlink, 411 .mkdir = ext2_mkdir, 412 .rmdir = ext2_rmdir, 413 .mknod = ext2_mknod, 414 .rename = ext2_rename, 415 #ifdef CONFIG_EXT2_FS_XATTR 416 .setxattr = generic_setxattr, 417 .getxattr = generic_getxattr, 418 .listxattr = ext2_listxattr, 419 .removexattr = generic_removexattr, 420 #endif 421 .setattr = ext2_setattr, 422 .get_acl = ext2_get_acl, 423 .set_acl = ext2_set_acl, 424 .tmpfile = ext2_tmpfile, 425 }; 426 427 const struct inode_operations ext2_special_inode_operations = { 428 #ifdef CONFIG_EXT2_FS_XATTR 429 .setxattr = generic_setxattr, 430 .getxattr = generic_getxattr, 431 .listxattr = ext2_listxattr, 432 .removexattr = generic_removexattr, 433 #endif 434 .setattr = ext2_setattr, 435 .get_acl = ext2_get_acl, 436 .set_acl = ext2_set_acl, 437 }; 438