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 (IS_ERR(inode)) { 71 if (PTR_ERR(inode) == -ESTALE) { 72 ext2_error(dir->i_sb, __func__, 73 "deleted inode referenced: %lu", 74 (unsigned long) ino); 75 return ERR_PTR(-EIO); 76 } else { 77 return ERR_CAST(inode); 78 } 79 } 80 } 81 return d_splice_alias(inode, dentry); 82 } 83 84 struct dentry *ext2_get_parent(struct dentry *child) 85 { 86 struct qstr dotdot = {.name = "..", .len = 2}; 87 unsigned long ino = ext2_inode_by_name(child->d_inode, &dotdot); 88 if (!ino) 89 return ERR_PTR(-ENOENT); 90 return d_obtain_alias(ext2_iget(child->d_inode->i_sb, ino)); 91 } 92 93 /* 94 * By the time this is called, we already have created 95 * the directory cache entry for the new file, but it 96 * is so far negative - it has no inode. 97 * 98 * If the create succeeds, we fill in the inode information 99 * with d_instantiate(). 100 */ 101 static int ext2_create (struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd) 102 { 103 struct inode *inode; 104 105 dquot_initialize(dir); 106 107 inode = ext2_new_inode(dir, mode, &dentry->d_name); 108 if (IS_ERR(inode)) 109 return PTR_ERR(inode); 110 111 inode->i_op = &ext2_file_inode_operations; 112 if (ext2_use_xip(inode->i_sb)) { 113 inode->i_mapping->a_ops = &ext2_aops_xip; 114 inode->i_fop = &ext2_xip_file_operations; 115 } else if (test_opt(inode->i_sb, NOBH)) { 116 inode->i_mapping->a_ops = &ext2_nobh_aops; 117 inode->i_fop = &ext2_file_operations; 118 } else { 119 inode->i_mapping->a_ops = &ext2_aops; 120 inode->i_fop = &ext2_file_operations; 121 } 122 mark_inode_dirty(inode); 123 return ext2_add_nondir(dentry, inode); 124 } 125 126 static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev) 127 { 128 struct inode * inode; 129 int err; 130 131 if (!new_valid_dev(rdev)) 132 return -EINVAL; 133 134 dquot_initialize(dir); 135 136 inode = ext2_new_inode (dir, mode, &dentry->d_name); 137 err = PTR_ERR(inode); 138 if (!IS_ERR(inode)) { 139 init_special_inode(inode, inode->i_mode, rdev); 140 #ifdef CONFIG_EXT2_FS_XATTR 141 inode->i_op = &ext2_special_inode_operations; 142 #endif 143 mark_inode_dirty(inode); 144 err = ext2_add_nondir(dentry, inode); 145 } 146 return err; 147 } 148 149 static int ext2_symlink (struct inode * dir, struct dentry * dentry, 150 const char * symname) 151 { 152 struct super_block * sb = dir->i_sb; 153 int err = -ENAMETOOLONG; 154 unsigned l = strlen(symname)+1; 155 struct inode * inode; 156 157 if (l > sb->s_blocksize) 158 goto out; 159 160 dquot_initialize(dir); 161 162 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name); 163 err = PTR_ERR(inode); 164 if (IS_ERR(inode)) 165 goto out; 166 167 if (l > sizeof (EXT2_I(inode)->i_data)) { 168 /* slow symlink */ 169 inode->i_op = &ext2_symlink_inode_operations; 170 if (test_opt(inode->i_sb, NOBH)) 171 inode->i_mapping->a_ops = &ext2_nobh_aops; 172 else 173 inode->i_mapping->a_ops = &ext2_aops; 174 err = page_symlink(inode, symname, l); 175 if (err) 176 goto out_fail; 177 } else { 178 /* fast symlink */ 179 inode->i_op = &ext2_fast_symlink_inode_operations; 180 memcpy((char*)(EXT2_I(inode)->i_data),symname,l); 181 inode->i_size = l-1; 182 } 183 mark_inode_dirty(inode); 184 185 err = ext2_add_nondir(dentry, inode); 186 out: 187 return err; 188 189 out_fail: 190 inode_dec_link_count(inode); 191 unlock_new_inode(inode); 192 iput (inode); 193 goto out; 194 } 195 196 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 197 struct dentry *dentry) 198 { 199 struct inode *inode = old_dentry->d_inode; 200 int err; 201 202 if (inode->i_nlink >= EXT2_LINK_MAX) 203 return -EMLINK; 204 205 dquot_initialize(dir); 206 207 inode->i_ctime = CURRENT_TIME_SEC; 208 inode_inc_link_count(inode); 209 ihold(inode); 210 211 err = ext2_add_link(dentry, inode); 212 if (!err) { 213 d_instantiate(dentry, inode); 214 return 0; 215 } 216 inode_dec_link_count(inode); 217 iput(inode); 218 return err; 219 } 220 221 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode) 222 { 223 struct inode * inode; 224 int err = -EMLINK; 225 226 if (dir->i_nlink >= EXT2_LINK_MAX) 227 goto out; 228 229 dquot_initialize(dir); 230 231 inode_inc_link_count(dir); 232 233 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 234 err = PTR_ERR(inode); 235 if (IS_ERR(inode)) 236 goto out_dir; 237 238 inode->i_op = &ext2_dir_inode_operations; 239 inode->i_fop = &ext2_dir_operations; 240 if (test_opt(inode->i_sb, NOBH)) 241 inode->i_mapping->a_ops = &ext2_nobh_aops; 242 else 243 inode->i_mapping->a_ops = &ext2_aops; 244 245 inode_inc_link_count(inode); 246 247 err = ext2_make_empty(inode, dir); 248 if (err) 249 goto out_fail; 250 251 err = ext2_add_link(dentry, inode); 252 if (err) 253 goto out_fail; 254 255 d_instantiate(dentry, inode); 256 unlock_new_inode(inode); 257 out: 258 return err; 259 260 out_fail: 261 inode_dec_link_count(inode); 262 inode_dec_link_count(inode); 263 unlock_new_inode(inode); 264 iput(inode); 265 out_dir: 266 inode_dec_link_count(dir); 267 goto out; 268 } 269 270 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 271 { 272 struct inode * inode = dentry->d_inode; 273 struct ext2_dir_entry_2 * de; 274 struct page * page; 275 int err = -ENOENT; 276 277 dquot_initialize(dir); 278 279 de = ext2_find_entry (dir, &dentry->d_name, &page); 280 if (!de) 281 goto out; 282 283 err = ext2_delete_entry (de, page); 284 if (err) 285 goto out; 286 287 inode->i_ctime = dir->i_ctime; 288 inode_dec_link_count(inode); 289 err = 0; 290 out: 291 return err; 292 } 293 294 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 295 { 296 struct inode * inode = dentry->d_inode; 297 int err = -ENOTEMPTY; 298 299 if (ext2_empty_dir(inode)) { 300 err = ext2_unlink(dir, dentry); 301 if (!err) { 302 inode->i_size = 0; 303 inode_dec_link_count(inode); 304 inode_dec_link_count(dir); 305 } 306 } 307 return err; 308 } 309 310 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 311 struct inode * new_dir, struct dentry * new_dentry ) 312 { 313 struct inode * old_inode = old_dentry->d_inode; 314 struct inode * new_inode = new_dentry->d_inode; 315 struct page * dir_page = NULL; 316 struct ext2_dir_entry_2 * dir_de = NULL; 317 struct page * old_page; 318 struct ext2_dir_entry_2 * old_de; 319 int err = -ENOENT; 320 321 dquot_initialize(old_dir); 322 dquot_initialize(new_dir); 323 324 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page); 325 if (!old_de) 326 goto out; 327 328 if (S_ISDIR(old_inode->i_mode)) { 329 err = -EIO; 330 dir_de = ext2_dotdot(old_inode, &dir_page); 331 if (!dir_de) 332 goto out_old; 333 } 334 335 if (new_inode) { 336 struct page *new_page; 337 struct ext2_dir_entry_2 *new_de; 338 339 err = -ENOTEMPTY; 340 if (dir_de && !ext2_empty_dir (new_inode)) 341 goto out_dir; 342 343 err = -ENOENT; 344 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page); 345 if (!new_de) 346 goto out_dir; 347 ext2_set_link(new_dir, new_de, new_page, old_inode, 1); 348 new_inode->i_ctime = CURRENT_TIME_SEC; 349 if (dir_de) 350 drop_nlink(new_inode); 351 inode_dec_link_count(new_inode); 352 } else { 353 if (dir_de) { 354 err = -EMLINK; 355 if (new_dir->i_nlink >= EXT2_LINK_MAX) 356 goto out_dir; 357 } 358 err = ext2_add_link(new_dentry, old_inode); 359 if (err) 360 goto out_dir; 361 if (dir_de) 362 inode_inc_link_count(new_dir); 363 } 364 365 /* 366 * Like most other Unix systems, set the ctime for inodes on a 367 * rename. 368 */ 369 old_inode->i_ctime = CURRENT_TIME_SEC; 370 mark_inode_dirty(old_inode); 371 372 ext2_delete_entry (old_de, old_page); 373 374 if (dir_de) { 375 if (old_dir != new_dir) 376 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0); 377 else { 378 kunmap(dir_page); 379 page_cache_release(dir_page); 380 } 381 inode_dec_link_count(old_dir); 382 } 383 return 0; 384 385 386 out_dir: 387 if (dir_de) { 388 kunmap(dir_page); 389 page_cache_release(dir_page); 390 } 391 out_old: 392 kunmap(old_page); 393 page_cache_release(old_page); 394 out: 395 return err; 396 } 397 398 const struct inode_operations ext2_dir_inode_operations = { 399 .create = ext2_create, 400 .lookup = ext2_lookup, 401 .link = ext2_link, 402 .unlink = ext2_unlink, 403 .symlink = ext2_symlink, 404 .mkdir = ext2_mkdir, 405 .rmdir = ext2_rmdir, 406 .mknod = ext2_mknod, 407 .rename = ext2_rename, 408 #ifdef CONFIG_EXT2_FS_XATTR 409 .setxattr = generic_setxattr, 410 .getxattr = generic_getxattr, 411 .listxattr = ext2_listxattr, 412 .removexattr = generic_removexattr, 413 #endif 414 .setattr = ext2_setattr, 415 .check_acl = ext2_check_acl, 416 }; 417 418 const struct inode_operations ext2_special_inode_operations = { 419 #ifdef CONFIG_EXT2_FS_XATTR 420 .setxattr = generic_setxattr, 421 .getxattr = generic_getxattr, 422 .listxattr = ext2_listxattr, 423 .removexattr = generic_removexattr, 424 #endif 425 .setattr = ext2_setattr, 426 .check_acl = ext2_check_acl, 427 }; 428