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 d_instantiate(dentry, inode); 45 unlock_new_inode(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, struct nameidata *nd) 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 = {.name = "..", .len = 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, struct nameidata *nd) 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_mknod (struct inode * dir, struct dentry *dentry, umode_t mode, dev_t rdev) 123 { 124 struct inode * inode; 125 int err; 126 127 if (!new_valid_dev(rdev)) 128 return -EINVAL; 129 130 dquot_initialize(dir); 131 132 inode = ext2_new_inode (dir, mode, &dentry->d_name); 133 err = PTR_ERR(inode); 134 if (!IS_ERR(inode)) { 135 init_special_inode(inode, inode->i_mode, rdev); 136 #ifdef CONFIG_EXT2_FS_XATTR 137 inode->i_op = &ext2_special_inode_operations; 138 #endif 139 mark_inode_dirty(inode); 140 err = ext2_add_nondir(dentry, inode); 141 } 142 return err; 143 } 144 145 static int ext2_symlink (struct inode * dir, struct dentry * dentry, 146 const char * symname) 147 { 148 struct super_block * sb = dir->i_sb; 149 int err = -ENAMETOOLONG; 150 unsigned l = strlen(symname)+1; 151 struct inode * inode; 152 153 if (l > sb->s_blocksize) 154 goto out; 155 156 dquot_initialize(dir); 157 158 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name); 159 err = PTR_ERR(inode); 160 if (IS_ERR(inode)) 161 goto out; 162 163 if (l > sizeof (EXT2_I(inode)->i_data)) { 164 /* slow symlink */ 165 inode->i_op = &ext2_symlink_inode_operations; 166 if (test_opt(inode->i_sb, NOBH)) 167 inode->i_mapping->a_ops = &ext2_nobh_aops; 168 else 169 inode->i_mapping->a_ops = &ext2_aops; 170 err = page_symlink(inode, symname, l); 171 if (err) 172 goto out_fail; 173 } else { 174 /* fast symlink */ 175 inode->i_op = &ext2_fast_symlink_inode_operations; 176 memcpy((char*)(EXT2_I(inode)->i_data),symname,l); 177 inode->i_size = l-1; 178 } 179 mark_inode_dirty(inode); 180 181 err = ext2_add_nondir(dentry, inode); 182 out: 183 return err; 184 185 out_fail: 186 inode_dec_link_count(inode); 187 unlock_new_inode(inode); 188 iput (inode); 189 goto out; 190 } 191 192 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 193 struct dentry *dentry) 194 { 195 struct inode *inode = old_dentry->d_inode; 196 int err; 197 198 if (inode->i_nlink >= EXT2_LINK_MAX) 199 return -EMLINK; 200 201 dquot_initialize(dir); 202 203 inode->i_ctime = CURRENT_TIME_SEC; 204 inode_inc_link_count(inode); 205 ihold(inode); 206 207 err = ext2_add_link(dentry, inode); 208 if (!err) { 209 d_instantiate(dentry, inode); 210 return 0; 211 } 212 inode_dec_link_count(inode); 213 iput(inode); 214 return err; 215 } 216 217 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode) 218 { 219 struct inode * inode; 220 int err = -EMLINK; 221 222 if (dir->i_nlink >= EXT2_LINK_MAX) 223 goto out; 224 225 dquot_initialize(dir); 226 227 inode_inc_link_count(dir); 228 229 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 230 err = PTR_ERR(inode); 231 if (IS_ERR(inode)) 232 goto out_dir; 233 234 inode->i_op = &ext2_dir_inode_operations; 235 inode->i_fop = &ext2_dir_operations; 236 if (test_opt(inode->i_sb, NOBH)) 237 inode->i_mapping->a_ops = &ext2_nobh_aops; 238 else 239 inode->i_mapping->a_ops = &ext2_aops; 240 241 inode_inc_link_count(inode); 242 243 err = ext2_make_empty(inode, dir); 244 if (err) 245 goto out_fail; 246 247 err = ext2_add_link(dentry, inode); 248 if (err) 249 goto out_fail; 250 251 d_instantiate(dentry, inode); 252 unlock_new_inode(inode); 253 out: 254 return err; 255 256 out_fail: 257 inode_dec_link_count(inode); 258 inode_dec_link_count(inode); 259 unlock_new_inode(inode); 260 iput(inode); 261 out_dir: 262 inode_dec_link_count(dir); 263 goto out; 264 } 265 266 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 267 { 268 struct inode * inode = dentry->d_inode; 269 struct ext2_dir_entry_2 * de; 270 struct page * page; 271 int err = -ENOENT; 272 273 dquot_initialize(dir); 274 275 de = ext2_find_entry (dir, &dentry->d_name, &page); 276 if (!de) 277 goto out; 278 279 err = ext2_delete_entry (de, page); 280 if (err) 281 goto out; 282 283 inode->i_ctime = dir->i_ctime; 284 inode_dec_link_count(inode); 285 err = 0; 286 out: 287 return err; 288 } 289 290 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 291 { 292 struct inode * inode = dentry->d_inode; 293 int err = -ENOTEMPTY; 294 295 if (ext2_empty_dir(inode)) { 296 err = ext2_unlink(dir, dentry); 297 if (!err) { 298 inode->i_size = 0; 299 inode_dec_link_count(inode); 300 inode_dec_link_count(dir); 301 } 302 } 303 return err; 304 } 305 306 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 307 struct inode * new_dir, struct dentry * new_dentry ) 308 { 309 struct inode * old_inode = old_dentry->d_inode; 310 struct inode * new_inode = new_dentry->d_inode; 311 struct page * dir_page = NULL; 312 struct ext2_dir_entry_2 * dir_de = NULL; 313 struct page * old_page; 314 struct ext2_dir_entry_2 * old_de; 315 int err = -ENOENT; 316 317 dquot_initialize(old_dir); 318 dquot_initialize(new_dir); 319 320 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page); 321 if (!old_de) 322 goto out; 323 324 if (S_ISDIR(old_inode->i_mode)) { 325 err = -EIO; 326 dir_de = ext2_dotdot(old_inode, &dir_page); 327 if (!dir_de) 328 goto out_old; 329 } 330 331 if (new_inode) { 332 struct page *new_page; 333 struct ext2_dir_entry_2 *new_de; 334 335 err = -ENOTEMPTY; 336 if (dir_de && !ext2_empty_dir (new_inode)) 337 goto out_dir; 338 339 err = -ENOENT; 340 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page); 341 if (!new_de) 342 goto out_dir; 343 ext2_set_link(new_dir, new_de, new_page, old_inode, 1); 344 new_inode->i_ctime = CURRENT_TIME_SEC; 345 if (dir_de) 346 drop_nlink(new_inode); 347 inode_dec_link_count(new_inode); 348 } else { 349 if (dir_de) { 350 err = -EMLINK; 351 if (new_dir->i_nlink >= EXT2_LINK_MAX) 352 goto out_dir; 353 } 354 err = ext2_add_link(new_dentry, old_inode); 355 if (err) 356 goto out_dir; 357 if (dir_de) 358 inode_inc_link_count(new_dir); 359 } 360 361 /* 362 * Like most other Unix systems, set the ctime for inodes on a 363 * rename. 364 */ 365 old_inode->i_ctime = CURRENT_TIME_SEC; 366 mark_inode_dirty(old_inode); 367 368 ext2_delete_entry (old_de, old_page); 369 370 if (dir_de) { 371 if (old_dir != new_dir) 372 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0); 373 else { 374 kunmap(dir_page); 375 page_cache_release(dir_page); 376 } 377 inode_dec_link_count(old_dir); 378 } 379 return 0; 380 381 382 out_dir: 383 if (dir_de) { 384 kunmap(dir_page); 385 page_cache_release(dir_page); 386 } 387 out_old: 388 kunmap(old_page); 389 page_cache_release(old_page); 390 out: 391 return err; 392 } 393 394 const struct inode_operations ext2_dir_inode_operations = { 395 .create = ext2_create, 396 .lookup = ext2_lookup, 397 .link = ext2_link, 398 .unlink = ext2_unlink, 399 .symlink = ext2_symlink, 400 .mkdir = ext2_mkdir, 401 .rmdir = ext2_rmdir, 402 .mknod = ext2_mknod, 403 .rename = ext2_rename, 404 #ifdef CONFIG_EXT2_FS_XATTR 405 .setxattr = generic_setxattr, 406 .getxattr = generic_getxattr, 407 .listxattr = ext2_listxattr, 408 .removexattr = generic_removexattr, 409 #endif 410 .setattr = ext2_setattr, 411 .get_acl = ext2_get_acl, 412 }; 413 414 const struct inode_operations ext2_special_inode_operations = { 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 }; 424