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 #include "xip.h" 39 40 static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode) 41 { 42 int err = ext2_add_link(dentry, inode); 43 if (!err) { 44 unlock_new_inode(inode); 45 d_instantiate(dentry, inode); 46 return 0; 47 } 48 inode_dec_link_count(inode); 49 unlock_new_inode(inode); 50 iput(inode); 51 return err; 52 } 53 54 /* 55 * Methods themselves. 56 */ 57 58 static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags) 59 { 60 struct inode * inode; 61 ino_t ino; 62 63 if (dentry->d_name.len > EXT2_NAME_LEN) 64 return ERR_PTR(-ENAMETOOLONG); 65 66 ino = ext2_inode_by_name(dir, &dentry->d_name); 67 inode = NULL; 68 if (ino) { 69 inode = ext2_iget(dir->i_sb, ino); 70 if (inode == ERR_PTR(-ESTALE)) { 71 ext2_error(dir->i_sb, __func__, 72 "deleted inode referenced: %lu", 73 (unsigned long) ino); 74 return ERR_PTR(-EIO); 75 } 76 } 77 return d_splice_alias(inode, dentry); 78 } 79 80 struct dentry *ext2_get_parent(struct dentry *child) 81 { 82 struct qstr dotdot = QSTR_INIT("..", 2); 83 unsigned long ino = ext2_inode_by_name(child->d_inode, &dotdot); 84 if (!ino) 85 return ERR_PTR(-ENOENT); 86 return d_obtain_alias(ext2_iget(child->d_inode->i_sb, ino)); 87 } 88 89 /* 90 * By the time this is called, we already have created 91 * the directory cache entry for the new file, but it 92 * is so far negative - it has no inode. 93 * 94 * If the create succeeds, we fill in the inode information 95 * with d_instantiate(). 96 */ 97 static int ext2_create (struct inode * dir, struct dentry * dentry, umode_t mode, bool excl) 98 { 99 struct inode *inode; 100 101 dquot_initialize(dir); 102 103 inode = ext2_new_inode(dir, mode, &dentry->d_name); 104 if (IS_ERR(inode)) 105 return PTR_ERR(inode); 106 107 inode->i_op = &ext2_file_inode_operations; 108 if (ext2_use_xip(inode->i_sb)) { 109 inode->i_mapping->a_ops = &ext2_aops_xip; 110 inode->i_fop = &ext2_xip_file_operations; 111 } else if (test_opt(inode->i_sb, NOBH)) { 112 inode->i_mapping->a_ops = &ext2_nobh_aops; 113 inode->i_fop = &ext2_file_operations; 114 } else { 115 inode->i_mapping->a_ops = &ext2_aops; 116 inode->i_fop = &ext2_file_operations; 117 } 118 mark_inode_dirty(inode); 119 return ext2_add_nondir(dentry, inode); 120 } 121 122 static int ext2_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) 123 { 124 struct inode *inode = ext2_new_inode(dir, mode, NULL); 125 if (IS_ERR(inode)) 126 return PTR_ERR(inode); 127 128 inode->i_op = &ext2_file_inode_operations; 129 if (ext2_use_xip(inode->i_sb)) { 130 inode->i_mapping->a_ops = &ext2_aops_xip; 131 inode->i_fop = &ext2_xip_file_operations; 132 } else if (test_opt(inode->i_sb, NOBH)) { 133 inode->i_mapping->a_ops = &ext2_nobh_aops; 134 inode->i_fop = &ext2_file_operations; 135 } else { 136 inode->i_mapping->a_ops = &ext2_aops; 137 inode->i_fop = &ext2_file_operations; 138 } 139 mark_inode_dirty(inode); 140 d_tmpfile(dentry, inode); 141 unlock_new_inode(inode); 142 return 0; 143 } 144 145 static int ext2_mknod (struct inode * dir, struct dentry *dentry, umode_t mode, dev_t rdev) 146 { 147 struct inode * inode; 148 int err; 149 150 if (!new_valid_dev(rdev)) 151 return -EINVAL; 152 153 dquot_initialize(dir); 154 155 inode = ext2_new_inode (dir, mode, &dentry->d_name); 156 err = PTR_ERR(inode); 157 if (!IS_ERR(inode)) { 158 init_special_inode(inode, inode->i_mode, rdev); 159 #ifdef CONFIG_EXT2_FS_XATTR 160 inode->i_op = &ext2_special_inode_operations; 161 #endif 162 mark_inode_dirty(inode); 163 err = ext2_add_nondir(dentry, inode); 164 } 165 return err; 166 } 167 168 static int ext2_symlink (struct inode * dir, struct dentry * dentry, 169 const char * symname) 170 { 171 struct super_block * sb = dir->i_sb; 172 int err = -ENAMETOOLONG; 173 unsigned l = strlen(symname)+1; 174 struct inode * inode; 175 176 if (l > sb->s_blocksize) 177 goto out; 178 179 dquot_initialize(dir); 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 memcpy((char*)(EXT2_I(inode)->i_data),symname,l); 200 inode->i_size = l-1; 201 } 202 mark_inode_dirty(inode); 203 204 err = ext2_add_nondir(dentry, inode); 205 out: 206 return err; 207 208 out_fail: 209 inode_dec_link_count(inode); 210 unlock_new_inode(inode); 211 iput (inode); 212 goto out; 213 } 214 215 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 216 struct dentry *dentry) 217 { 218 struct inode *inode = old_dentry->d_inode; 219 int err; 220 221 dquot_initialize(dir); 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 dquot_initialize(dir); 243 244 inode_inc_link_count(dir); 245 246 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 247 err = PTR_ERR(inode); 248 if (IS_ERR(inode)) 249 goto out_dir; 250 251 inode->i_op = &ext2_dir_inode_operations; 252 inode->i_fop = &ext2_dir_operations; 253 if (test_opt(inode->i_sb, NOBH)) 254 inode->i_mapping->a_ops = &ext2_nobh_aops; 255 else 256 inode->i_mapping->a_ops = &ext2_aops; 257 258 inode_inc_link_count(inode); 259 260 err = ext2_make_empty(inode, dir); 261 if (err) 262 goto out_fail; 263 264 err = ext2_add_link(dentry, inode); 265 if (err) 266 goto out_fail; 267 268 unlock_new_inode(inode); 269 d_instantiate(dentry, inode); 270 out: 271 return err; 272 273 out_fail: 274 inode_dec_link_count(inode); 275 inode_dec_link_count(inode); 276 unlock_new_inode(inode); 277 iput(inode); 278 out_dir: 279 inode_dec_link_count(dir); 280 goto out; 281 } 282 283 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 284 { 285 struct inode * inode = dentry->d_inode; 286 struct ext2_dir_entry_2 * de; 287 struct page * page; 288 int err = -ENOENT; 289 290 dquot_initialize(dir); 291 292 de = ext2_find_entry (dir, &dentry->d_name, &page); 293 if (!de) 294 goto out; 295 296 err = ext2_delete_entry (de, page); 297 if (err) 298 goto out; 299 300 inode->i_ctime = dir->i_ctime; 301 inode_dec_link_count(inode); 302 err = 0; 303 out: 304 return err; 305 } 306 307 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 308 { 309 struct inode * inode = dentry->d_inode; 310 int err = -ENOTEMPTY; 311 312 if (ext2_empty_dir(inode)) { 313 err = ext2_unlink(dir, dentry); 314 if (!err) { 315 inode->i_size = 0; 316 inode_dec_link_count(inode); 317 inode_dec_link_count(dir); 318 } 319 } 320 return err; 321 } 322 323 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 324 struct inode * new_dir, struct dentry * new_dentry ) 325 { 326 struct inode * old_inode = old_dentry->d_inode; 327 struct inode * new_inode = new_dentry->d_inode; 328 struct page * dir_page = NULL; 329 struct ext2_dir_entry_2 * dir_de = NULL; 330 struct page * old_page; 331 struct ext2_dir_entry_2 * old_de; 332 int err = -ENOENT; 333 334 dquot_initialize(old_dir); 335 dquot_initialize(new_dir); 336 337 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page); 338 if (!old_de) 339 goto out; 340 341 if (S_ISDIR(old_inode->i_mode)) { 342 err = -EIO; 343 dir_de = ext2_dotdot(old_inode, &dir_page); 344 if (!dir_de) 345 goto out_old; 346 } 347 348 if (new_inode) { 349 struct page *new_page; 350 struct ext2_dir_entry_2 *new_de; 351 352 err = -ENOTEMPTY; 353 if (dir_de && !ext2_empty_dir (new_inode)) 354 goto out_dir; 355 356 err = -ENOENT; 357 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page); 358 if (!new_de) 359 goto out_dir; 360 ext2_set_link(new_dir, new_de, new_page, old_inode, 1); 361 new_inode->i_ctime = CURRENT_TIME_SEC; 362 if (dir_de) 363 drop_nlink(new_inode); 364 inode_dec_link_count(new_inode); 365 } else { 366 err = ext2_add_link(new_dentry, old_inode); 367 if (err) 368 goto out_dir; 369 if (dir_de) 370 inode_inc_link_count(new_dir); 371 } 372 373 /* 374 * Like most other Unix systems, set the ctime for inodes on a 375 * rename. 376 */ 377 old_inode->i_ctime = CURRENT_TIME_SEC; 378 mark_inode_dirty(old_inode); 379 380 ext2_delete_entry (old_de, old_page); 381 382 if (dir_de) { 383 if (old_dir != new_dir) 384 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0); 385 else { 386 kunmap(dir_page); 387 page_cache_release(dir_page); 388 } 389 inode_dec_link_count(old_dir); 390 } 391 return 0; 392 393 394 out_dir: 395 if (dir_de) { 396 kunmap(dir_page); 397 page_cache_release(dir_page); 398 } 399 out_old: 400 kunmap(old_page); 401 page_cache_release(old_page); 402 out: 403 return err; 404 } 405 406 const struct inode_operations ext2_dir_inode_operations = { 407 .create = ext2_create, 408 .lookup = ext2_lookup, 409 .link = ext2_link, 410 .unlink = ext2_unlink, 411 .symlink = ext2_symlink, 412 .mkdir = ext2_mkdir, 413 .rmdir = ext2_rmdir, 414 .mknod = ext2_mknod, 415 .rename = ext2_rename, 416 #ifdef CONFIG_EXT2_FS_XATTR 417 .setxattr = generic_setxattr, 418 .getxattr = generic_getxattr, 419 .listxattr = ext2_listxattr, 420 .removexattr = generic_removexattr, 421 #endif 422 .setattr = ext2_setattr, 423 .get_acl = ext2_get_acl, 424 .set_acl = ext2_set_acl, 425 .tmpfile = ext2_tmpfile, 426 }; 427 428 const struct inode_operations ext2_special_inode_operations = { 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 }; 439