1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * linux/fs/ext2/namei.c 4 * 5 * Rewrite to pagecache. Almost all code had been changed, so blame me 6 * if the things go wrong. Please, send bug reports to 7 * viro@parcelfarce.linux.theplanet.co.uk 8 * 9 * Stuff here is basically a glue between the VFS and generic UNIXish 10 * filesystem that keeps everything in pagecache. All knowledge of the 11 * directory layout is in fs/ext2/dir.c - it turned out to be easily separatable 12 * and it's easier to debug that way. In principle we might want to 13 * generalize that a bit and turn it into a library. Or not. 14 * 15 * The only non-static object here is ext2_dir_inode_operations. 16 * 17 * TODO: get rid of kmap() use, add readahead. 18 * 19 * Copyright (C) 1992, 1993, 1994, 1995 20 * Remy Card (card@masi.ibp.fr) 21 * Laboratoire MASI - Institut Blaise Pascal 22 * Universite Pierre et Marie Curie (Paris VI) 23 * 24 * from 25 * 26 * linux/fs/minix/namei.c 27 * 28 * Copyright (C) 1991, 1992 Linus Torvalds 29 * 30 * Big-endian to little-endian byte-swapping/bitmaps by 31 * David S. Miller (davem@caip.rutgers.edu), 1995 32 */ 33 34 #include <linux/pagemap.h> 35 #include <linux/quotaops.h> 36 #include "ext2.h" 37 #include "xattr.h" 38 #include "acl.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_new(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(child->d_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 int err; 100 101 err = dquot_initialize(dir); 102 if (err) 103 return err; 104 105 inode = ext2_new_inode(dir, mode, &dentry->d_name); 106 if (IS_ERR(inode)) 107 return PTR_ERR(inode); 108 109 ext2_set_file_ops(inode); 110 mark_inode_dirty(inode); 111 return ext2_add_nondir(dentry, inode); 112 } 113 114 static int ext2_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) 115 { 116 struct inode *inode = ext2_new_inode(dir, mode, NULL); 117 if (IS_ERR(inode)) 118 return PTR_ERR(inode); 119 120 ext2_set_file_ops(inode); 121 mark_inode_dirty(inode); 122 d_tmpfile(dentry, inode); 123 unlock_new_inode(inode); 124 return 0; 125 } 126 127 static int ext2_mknod (struct inode * dir, struct dentry *dentry, umode_t mode, dev_t rdev) 128 { 129 struct inode * inode; 130 int err; 131 132 err = dquot_initialize(dir); 133 if (err) 134 return err; 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 err = dquot_initialize(dir); 161 if (err) 162 goto out; 163 164 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name); 165 err = PTR_ERR(inode); 166 if (IS_ERR(inode)) 167 goto out; 168 169 if (l > sizeof (EXT2_I(inode)->i_data)) { 170 /* slow symlink */ 171 inode->i_op = &ext2_symlink_inode_operations; 172 inode_nohighmem(inode); 173 if (test_opt(inode->i_sb, NOBH)) 174 inode->i_mapping->a_ops = &ext2_nobh_aops; 175 else 176 inode->i_mapping->a_ops = &ext2_aops; 177 err = page_symlink(inode, symname, l); 178 if (err) 179 goto out_fail; 180 } else { 181 /* fast symlink */ 182 inode->i_op = &ext2_fast_symlink_inode_operations; 183 inode->i_link = (char*)EXT2_I(inode)->i_data; 184 memcpy(inode->i_link, symname, l); 185 inode->i_size = l-1; 186 } 187 mark_inode_dirty(inode); 188 189 err = ext2_add_nondir(dentry, inode); 190 out: 191 return err; 192 193 out_fail: 194 inode_dec_link_count(inode); 195 unlock_new_inode(inode); 196 iput (inode); 197 goto out; 198 } 199 200 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 201 struct dentry *dentry) 202 { 203 struct inode *inode = d_inode(old_dentry); 204 int err; 205 206 err = dquot_initialize(dir); 207 if (err) 208 return err; 209 210 inode->i_ctime = current_time(inode); 211 inode_inc_link_count(inode); 212 ihold(inode); 213 214 err = ext2_add_link(dentry, inode); 215 if (!err) { 216 d_instantiate(dentry, inode); 217 return 0; 218 } 219 inode_dec_link_count(inode); 220 iput(inode); 221 return err; 222 } 223 224 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode) 225 { 226 struct inode * inode; 227 int err; 228 229 err = dquot_initialize(dir); 230 if (err) 231 return err; 232 233 inode_inc_link_count(dir); 234 235 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 236 err = PTR_ERR(inode); 237 if (IS_ERR(inode)) 238 goto out_dir; 239 240 inode->i_op = &ext2_dir_inode_operations; 241 inode->i_fop = &ext2_dir_operations; 242 if (test_opt(inode->i_sb, NOBH)) 243 inode->i_mapping->a_ops = &ext2_nobh_aops; 244 else 245 inode->i_mapping->a_ops = &ext2_aops; 246 247 inode_inc_link_count(inode); 248 249 err = ext2_make_empty(inode, dir); 250 if (err) 251 goto out_fail; 252 253 err = ext2_add_link(dentry, inode); 254 if (err) 255 goto out_fail; 256 257 d_instantiate_new(dentry, inode); 258 out: 259 return err; 260 261 out_fail: 262 inode_dec_link_count(inode); 263 inode_dec_link_count(inode); 264 unlock_new_inode(inode); 265 iput(inode); 266 out_dir: 267 inode_dec_link_count(dir); 268 goto out; 269 } 270 271 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 272 { 273 struct inode * inode = d_inode(dentry); 274 struct ext2_dir_entry_2 * de; 275 struct page * page; 276 int err; 277 278 err = dquot_initialize(dir); 279 if (err) 280 goto out; 281 282 de = ext2_find_entry (dir, &dentry->d_name, &page); 283 if (!de) { 284 err = -ENOENT; 285 goto out; 286 } 287 288 err = ext2_delete_entry (de, page); 289 if (err) 290 goto out; 291 292 inode->i_ctime = dir->i_ctime; 293 inode_dec_link_count(inode); 294 err = 0; 295 out: 296 return err; 297 } 298 299 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 300 { 301 struct inode * inode = d_inode(dentry); 302 int err = -ENOTEMPTY; 303 304 if (ext2_empty_dir(inode)) { 305 err = ext2_unlink(dir, dentry); 306 if (!err) { 307 inode->i_size = 0; 308 inode_dec_link_count(inode); 309 inode_dec_link_count(dir); 310 } 311 } 312 return err; 313 } 314 315 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 316 struct inode * new_dir, struct dentry * new_dentry, 317 unsigned int flags) 318 { 319 struct inode * old_inode = d_inode(old_dentry); 320 struct inode * new_inode = d_inode(new_dentry); 321 struct page * dir_page = NULL; 322 struct ext2_dir_entry_2 * dir_de = NULL; 323 struct page * old_page; 324 struct ext2_dir_entry_2 * old_de; 325 int err; 326 327 if (flags & ~RENAME_NOREPLACE) 328 return -EINVAL; 329 330 err = dquot_initialize(old_dir); 331 if (err) 332 goto out; 333 334 err = dquot_initialize(new_dir); 335 if (err) 336 goto out; 337 338 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page); 339 if (!old_de) { 340 err = -ENOENT; 341 goto out; 342 } 343 344 if (S_ISDIR(old_inode->i_mode)) { 345 err = -EIO; 346 dir_de = ext2_dotdot(old_inode, &dir_page); 347 if (!dir_de) 348 goto out_old; 349 } 350 351 if (new_inode) { 352 struct page *new_page; 353 struct ext2_dir_entry_2 *new_de; 354 355 err = -ENOTEMPTY; 356 if (dir_de && !ext2_empty_dir (new_inode)) 357 goto out_dir; 358 359 err = -ENOENT; 360 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page); 361 if (!new_de) 362 goto out_dir; 363 ext2_set_link(new_dir, new_de, new_page, old_inode, 1); 364 new_inode->i_ctime = current_time(new_inode); 365 if (dir_de) 366 drop_nlink(new_inode); 367 inode_dec_link_count(new_inode); 368 } else { 369 err = ext2_add_link(new_dentry, old_inode); 370 if (err) 371 goto out_dir; 372 if (dir_de) 373 inode_inc_link_count(new_dir); 374 } 375 376 /* 377 * Like most other Unix systems, set the ctime for inodes on a 378 * rename. 379 */ 380 old_inode->i_ctime = current_time(old_inode); 381 mark_inode_dirty(old_inode); 382 383 ext2_delete_entry (old_de, old_page); 384 385 if (dir_de) { 386 if (old_dir != new_dir) 387 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0); 388 else { 389 kunmap(dir_page); 390 put_page(dir_page); 391 } 392 inode_dec_link_count(old_dir); 393 } 394 return 0; 395 396 397 out_dir: 398 if (dir_de) { 399 kunmap(dir_page); 400 put_page(dir_page); 401 } 402 out_old: 403 kunmap(old_page); 404 put_page(old_page); 405 out: 406 return err; 407 } 408 409 const struct inode_operations ext2_dir_inode_operations = { 410 .create = ext2_create, 411 .lookup = ext2_lookup, 412 .link = ext2_link, 413 .unlink = ext2_unlink, 414 .symlink = ext2_symlink, 415 .mkdir = ext2_mkdir, 416 .rmdir = ext2_rmdir, 417 .mknod = ext2_mknod, 418 .rename = ext2_rename, 419 #ifdef CONFIG_EXT2_FS_XATTR 420 .listxattr = ext2_listxattr, 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 .listxattr = ext2_listxattr, 431 #endif 432 .setattr = ext2_setattr, 433 .get_acl = ext2_get_acl, 434 .set_acl = ext2_set_acl, 435 }; 436