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; 99 100 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, NOBH)) { 108 inode->i_mapping->a_ops = &ext2_nobh_aops; 109 inode->i_fop = &ext2_file_operations; 110 } else { 111 inode->i_mapping->a_ops = &ext2_aops; 112 inode->i_fop = &ext2_file_operations; 113 } 114 mark_inode_dirty(inode); 115 return ext2_add_nondir(dentry, inode); 116 } 117 118 static int ext2_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) 119 { 120 struct inode *inode = ext2_new_inode(dir, mode, NULL); 121 if (IS_ERR(inode)) 122 return PTR_ERR(inode); 123 124 inode->i_op = &ext2_file_inode_operations; 125 if (test_opt(inode->i_sb, NOBH)) { 126 inode->i_mapping->a_ops = &ext2_nobh_aops; 127 inode->i_fop = &ext2_file_operations; 128 } else { 129 inode->i_mapping->a_ops = &ext2_aops; 130 inode->i_fop = &ext2_file_operations; 131 } 132 mark_inode_dirty(inode); 133 d_tmpfile(dentry, inode); 134 unlock_new_inode(inode); 135 return 0; 136 } 137 138 static int ext2_mknod (struct inode * dir, struct dentry *dentry, umode_t mode, dev_t rdev) 139 { 140 struct inode * inode; 141 int err; 142 143 if (!new_valid_dev(rdev)) 144 return -EINVAL; 145 146 dquot_initialize(dir); 147 148 inode = ext2_new_inode (dir, mode, &dentry->d_name); 149 err = PTR_ERR(inode); 150 if (!IS_ERR(inode)) { 151 init_special_inode(inode, inode->i_mode, rdev); 152 #ifdef CONFIG_EXT2_FS_XATTR 153 inode->i_op = &ext2_special_inode_operations; 154 #endif 155 mark_inode_dirty(inode); 156 err = ext2_add_nondir(dentry, inode); 157 } 158 return err; 159 } 160 161 static int ext2_symlink (struct inode * dir, struct dentry * dentry, 162 const char * symname) 163 { 164 struct super_block * sb = dir->i_sb; 165 int err = -ENAMETOOLONG; 166 unsigned l = strlen(symname)+1; 167 struct inode * inode; 168 169 if (l > sb->s_blocksize) 170 goto out; 171 172 dquot_initialize(dir); 173 174 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name); 175 err = PTR_ERR(inode); 176 if (IS_ERR(inode)) 177 goto out; 178 179 if (l > sizeof (EXT2_I(inode)->i_data)) { 180 /* slow symlink */ 181 inode->i_op = &ext2_symlink_inode_operations; 182 if (test_opt(inode->i_sb, NOBH)) 183 inode->i_mapping->a_ops = &ext2_nobh_aops; 184 else 185 inode->i_mapping->a_ops = &ext2_aops; 186 err = page_symlink(inode, symname, l); 187 if (err) 188 goto out_fail; 189 } else { 190 /* fast symlink */ 191 inode->i_op = &ext2_fast_symlink_inode_operations; 192 inode->i_link = (char*)EXT2_I(inode)->i_data; 193 memcpy(inode->i_link, symname, l); 194 inode->i_size = l-1; 195 } 196 mark_inode_dirty(inode); 197 198 err = ext2_add_nondir(dentry, inode); 199 out: 200 return err; 201 202 out_fail: 203 inode_dec_link_count(inode); 204 unlock_new_inode(inode); 205 iput (inode); 206 goto out; 207 } 208 209 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 210 struct dentry *dentry) 211 { 212 struct inode *inode = d_inode(old_dentry); 213 int err; 214 215 dquot_initialize(dir); 216 217 inode->i_ctime = CURRENT_TIME_SEC; 218 inode_inc_link_count(inode); 219 ihold(inode); 220 221 err = ext2_add_link(dentry, inode); 222 if (!err) { 223 d_instantiate(dentry, inode); 224 return 0; 225 } 226 inode_dec_link_count(inode); 227 iput(inode); 228 return err; 229 } 230 231 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode) 232 { 233 struct inode * inode; 234 int err; 235 236 dquot_initialize(dir); 237 238 inode_inc_link_count(dir); 239 240 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 241 err = PTR_ERR(inode); 242 if (IS_ERR(inode)) 243 goto out_dir; 244 245 inode->i_op = &ext2_dir_inode_operations; 246 inode->i_fop = &ext2_dir_operations; 247 if (test_opt(inode->i_sb, NOBH)) 248 inode->i_mapping->a_ops = &ext2_nobh_aops; 249 else 250 inode->i_mapping->a_ops = &ext2_aops; 251 252 inode_inc_link_count(inode); 253 254 err = ext2_make_empty(inode, dir); 255 if (err) 256 goto out_fail; 257 258 err = ext2_add_link(dentry, inode); 259 if (err) 260 goto out_fail; 261 262 unlock_new_inode(inode); 263 d_instantiate(dentry, inode); 264 out: 265 return err; 266 267 out_fail: 268 inode_dec_link_count(inode); 269 inode_dec_link_count(inode); 270 unlock_new_inode(inode); 271 iput(inode); 272 out_dir: 273 inode_dec_link_count(dir); 274 goto out; 275 } 276 277 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 278 { 279 struct inode * inode = d_inode(dentry); 280 struct ext2_dir_entry_2 * de; 281 struct page * page; 282 int err = -ENOENT; 283 284 dquot_initialize(dir); 285 286 de = ext2_find_entry (dir, &dentry->d_name, &page); 287 if (!de) 288 goto out; 289 290 err = ext2_delete_entry (de, page); 291 if (err) 292 goto out; 293 294 inode->i_ctime = dir->i_ctime; 295 inode_dec_link_count(inode); 296 err = 0; 297 out: 298 return err; 299 } 300 301 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 302 { 303 struct inode * inode = d_inode(dentry); 304 int err = -ENOTEMPTY; 305 306 if (ext2_empty_dir(inode)) { 307 err = ext2_unlink(dir, dentry); 308 if (!err) { 309 inode->i_size = 0; 310 inode_dec_link_count(inode); 311 inode_dec_link_count(dir); 312 } 313 } 314 return err; 315 } 316 317 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 318 struct inode * new_dir, struct dentry * new_dentry ) 319 { 320 struct inode * old_inode = d_inode(old_dentry); 321 struct inode * new_inode = d_inode(new_dentry); 322 struct page * dir_page = NULL; 323 struct ext2_dir_entry_2 * dir_de = NULL; 324 struct page * old_page; 325 struct ext2_dir_entry_2 * old_de; 326 int err = -ENOENT; 327 328 dquot_initialize(old_dir); 329 dquot_initialize(new_dir); 330 331 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page); 332 if (!old_de) 333 goto out; 334 335 if (S_ISDIR(old_inode->i_mode)) { 336 err = -EIO; 337 dir_de = ext2_dotdot(old_inode, &dir_page); 338 if (!dir_de) 339 goto out_old; 340 } 341 342 if (new_inode) { 343 struct page *new_page; 344 struct ext2_dir_entry_2 *new_de; 345 346 err = -ENOTEMPTY; 347 if (dir_de && !ext2_empty_dir (new_inode)) 348 goto out_dir; 349 350 err = -ENOENT; 351 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page); 352 if (!new_de) 353 goto out_dir; 354 ext2_set_link(new_dir, new_de, new_page, old_inode, 1); 355 new_inode->i_ctime = CURRENT_TIME_SEC; 356 if (dir_de) 357 drop_nlink(new_inode); 358 inode_dec_link_count(new_inode); 359 } else { 360 err = ext2_add_link(new_dentry, old_inode); 361 if (err) 362 goto out_dir; 363 if (dir_de) 364 inode_inc_link_count(new_dir); 365 } 366 367 /* 368 * Like most other Unix systems, set the ctime for inodes on a 369 * rename. 370 */ 371 old_inode->i_ctime = CURRENT_TIME_SEC; 372 mark_inode_dirty(old_inode); 373 374 ext2_delete_entry (old_de, old_page); 375 376 if (dir_de) { 377 if (old_dir != new_dir) 378 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0); 379 else { 380 kunmap(dir_page); 381 page_cache_release(dir_page); 382 } 383 inode_dec_link_count(old_dir); 384 } 385 return 0; 386 387 388 out_dir: 389 if (dir_de) { 390 kunmap(dir_page); 391 page_cache_release(dir_page); 392 } 393 out_old: 394 kunmap(old_page); 395 page_cache_release(old_page); 396 out: 397 return err; 398 } 399 400 const struct inode_operations ext2_dir_inode_operations = { 401 .create = ext2_create, 402 .lookup = ext2_lookup, 403 .link = ext2_link, 404 .unlink = ext2_unlink, 405 .symlink = ext2_symlink, 406 .mkdir = ext2_mkdir, 407 .rmdir = ext2_rmdir, 408 .mknod = ext2_mknod, 409 .rename = ext2_rename, 410 #ifdef CONFIG_EXT2_FS_XATTR 411 .setxattr = generic_setxattr, 412 .getxattr = generic_getxattr, 413 .listxattr = ext2_listxattr, 414 .removexattr = generic_removexattr, 415 #endif 416 .setattr = ext2_setattr, 417 .get_acl = ext2_get_acl, 418 .set_acl = ext2_set_acl, 419 .tmpfile = ext2_tmpfile, 420 }; 421 422 const struct inode_operations ext2_special_inode_operations = { 423 #ifdef CONFIG_EXT2_FS_XATTR 424 .setxattr = generic_setxattr, 425 .getxattr = generic_getxattr, 426 .listxattr = ext2_listxattr, 427 .removexattr = generic_removexattr, 428 #endif 429 .setattr = ext2_setattr, 430 .get_acl = ext2_get_acl, 431 .set_acl = ext2_set_acl, 432 }; 433