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 * Copyright (C) 1992, 1993, 1994, 1995 18 * Remy Card (card@masi.ibp.fr) 19 * Laboratoire MASI - Institut Blaise Pascal 20 * Universite Pierre et Marie Curie (Paris VI) 21 * 22 * from 23 * 24 * linux/fs/minix/namei.c 25 * 26 * Copyright (C) 1991, 1992 Linus Torvalds 27 * 28 * Big-endian to little-endian byte-swapping/bitmaps by 29 * David S. Miller (davem@caip.rutgers.edu), 1995 30 */ 31 32 #include <linux/pagemap.h> 33 #include <linux/quotaops.h> 34 #include "ext2.h" 35 #include "xattr.h" 36 #include "acl.h" 37 38 static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode) 39 { 40 int err = ext2_add_link(dentry, inode); 41 if (!err) { 42 d_instantiate_new(dentry, inode); 43 return 0; 44 } 45 inode_dec_link_count(inode); 46 discard_new_inode(inode); 47 return err; 48 } 49 50 /* 51 * Methods themselves. 52 */ 53 54 static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags) 55 { 56 struct inode * inode; 57 ino_t ino; 58 int res; 59 60 if (dentry->d_name.len > EXT2_NAME_LEN) 61 return ERR_PTR(-ENAMETOOLONG); 62 63 res = ext2_inode_by_name(dir, &dentry->d_name, &ino); 64 if (res) { 65 if (res != -ENOENT) 66 return ERR_PTR(res); 67 inode = NULL; 68 } else { 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 ino_t ino; 83 int res; 84 85 res = ext2_inode_by_name(d_inode(child), &dotdot_name, &ino); 86 if (res) 87 return ERR_PTR(res); 88 89 return d_obtain_alias(ext2_iget(child->d_sb, ino)); 90 } 91 92 /* 93 * By the time this is called, we already have created 94 * the directory cache entry for the new file, but it 95 * is so far negative - it has no inode. 96 * 97 * If the create succeeds, we fill in the inode information 98 * with d_instantiate(). 99 */ 100 static int ext2_create (struct mnt_idmap * idmap, 101 struct inode * dir, struct dentry * dentry, 102 umode_t mode, bool excl) 103 { 104 struct inode *inode; 105 int err; 106 107 err = dquot_initialize(dir); 108 if (err) 109 return err; 110 111 inode = ext2_new_inode(dir, mode, &dentry->d_name); 112 if (IS_ERR(inode)) 113 return PTR_ERR(inode); 114 115 ext2_set_file_ops(inode); 116 mark_inode_dirty(inode); 117 return ext2_add_nondir(dentry, inode); 118 } 119 120 static int ext2_tmpfile(struct mnt_idmap *idmap, struct inode *dir, 121 struct file *file, umode_t mode) 122 { 123 struct inode *inode = ext2_new_inode(dir, mode, NULL); 124 if (IS_ERR(inode)) 125 return PTR_ERR(inode); 126 127 ext2_set_file_ops(inode); 128 mark_inode_dirty(inode); 129 d_tmpfile(file, inode); 130 unlock_new_inode(inode); 131 return finish_open_simple(file, 0); 132 } 133 134 static int ext2_mknod (struct mnt_idmap * idmap, struct inode * dir, 135 struct dentry *dentry, umode_t mode, dev_t rdev) 136 { 137 struct inode * inode; 138 int err; 139 140 err = dquot_initialize(dir); 141 if (err) 142 return err; 143 144 inode = ext2_new_inode (dir, mode, &dentry->d_name); 145 err = PTR_ERR(inode); 146 if (!IS_ERR(inode)) { 147 init_special_inode(inode, inode->i_mode, rdev); 148 inode->i_op = &ext2_special_inode_operations; 149 mark_inode_dirty(inode); 150 err = ext2_add_nondir(dentry, inode); 151 } 152 return err; 153 } 154 155 static int ext2_symlink (struct mnt_idmap * idmap, struct inode * dir, 156 struct dentry * dentry, const char * symname) 157 { 158 struct super_block * sb = dir->i_sb; 159 int err = -ENAMETOOLONG; 160 unsigned l = strlen(symname)+1; 161 struct inode * inode; 162 163 if (l > sb->s_blocksize) 164 goto out; 165 166 err = dquot_initialize(dir); 167 if (err) 168 goto out; 169 170 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name); 171 err = PTR_ERR(inode); 172 if (IS_ERR(inode)) 173 goto out; 174 175 if (l > sizeof (EXT2_I(inode)->i_data)) { 176 /* slow symlink */ 177 inode->i_op = &ext2_symlink_inode_operations; 178 inode_nohighmem(inode); 179 inode->i_mapping->a_ops = &ext2_aops; 180 err = page_symlink(inode, symname, l); 181 if (err) 182 goto out_fail; 183 } else { 184 /* fast symlink */ 185 inode->i_op = &ext2_fast_symlink_inode_operations; 186 inode->i_link = (char*)EXT2_I(inode)->i_data; 187 memcpy(inode->i_link, symname, l); 188 inode->i_size = l-1; 189 } 190 mark_inode_dirty(inode); 191 192 err = ext2_add_nondir(dentry, inode); 193 out: 194 return err; 195 196 out_fail: 197 inode_dec_link_count(inode); 198 discard_new_inode(inode); 199 goto out; 200 } 201 202 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 203 struct dentry *dentry) 204 { 205 struct inode *inode = d_inode(old_dentry); 206 int err; 207 208 err = dquot_initialize(dir); 209 if (err) 210 return err; 211 212 inode_set_ctime_current(inode); 213 inode_inc_link_count(inode); 214 ihold(inode); 215 216 err = ext2_add_link(dentry, inode); 217 if (!err) { 218 d_instantiate(dentry, inode); 219 return 0; 220 } 221 inode_dec_link_count(inode); 222 iput(inode); 223 return err; 224 } 225 226 static struct dentry *ext2_mkdir(struct mnt_idmap * idmap, 227 struct inode * dir, struct dentry * dentry, 228 umode_t mode) 229 { 230 struct inode * inode; 231 int err; 232 233 err = dquot_initialize(dir); 234 if (err) 235 return ERR_PTR(err); 236 237 inode_inc_link_count(dir); 238 239 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 240 err = PTR_ERR(inode); 241 if (IS_ERR(inode)) 242 goto out_dir; 243 244 inode->i_op = &ext2_dir_inode_operations; 245 inode->i_fop = &ext2_dir_operations; 246 inode->i_mapping->a_ops = &ext2_aops; 247 248 inode_inc_link_count(inode); 249 250 err = ext2_make_empty(inode, dir); 251 if (err) 252 goto out_fail; 253 254 err = ext2_add_link(dentry, inode); 255 if (err) 256 goto out_fail; 257 258 d_instantiate_new(dentry, inode); 259 out: 260 return ERR_PTR(err); 261 262 out_fail: 263 inode_dec_link_count(inode); 264 inode_dec_link_count(inode); 265 discard_new_inode(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 folio *folio; 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, &folio); 283 if (IS_ERR(de)) { 284 err = PTR_ERR(de); 285 goto out; 286 } 287 288 err = ext2_delete_entry(de, folio); 289 folio_release_kmap(folio, de); 290 if (err) 291 goto out; 292 293 inode_set_ctime_to_ts(inode, inode_get_ctime(dir)); 294 295 if (inode->i_nlink) 296 inode_dec_link_count(inode); 297 298 err = 0; 299 out: 300 return err; 301 } 302 303 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 304 { 305 struct inode * inode = d_inode(dentry); 306 int err = -ENOTEMPTY; 307 308 if (ext2_empty_dir(inode)) { 309 err = ext2_unlink(dir, dentry); 310 if (!err) { 311 inode->i_size = 0; 312 inode_dec_link_count(inode); 313 inode_dec_link_count(dir); 314 } 315 } 316 return err; 317 } 318 319 static int ext2_rename (struct mnt_idmap * idmap, 320 struct inode * old_dir, struct dentry * old_dentry, 321 struct inode * new_dir, struct dentry * new_dentry, 322 unsigned int flags) 323 { 324 struct inode * old_inode = d_inode(old_dentry); 325 struct inode * new_inode = d_inode(new_dentry); 326 struct folio *dir_folio = NULL; 327 struct ext2_dir_entry_2 * dir_de = NULL; 328 struct folio * old_folio; 329 struct ext2_dir_entry_2 * old_de; 330 bool old_is_dir = S_ISDIR(old_inode->i_mode); 331 int err; 332 333 if (flags & ~RENAME_NOREPLACE) 334 return -EINVAL; 335 336 err = dquot_initialize(old_dir); 337 if (err) 338 return err; 339 340 err = dquot_initialize(new_dir); 341 if (err) 342 return err; 343 344 old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_folio); 345 if (IS_ERR(old_de)) 346 return PTR_ERR(old_de); 347 348 if (old_is_dir && old_dir != new_dir) { 349 err = -EIO; 350 dir_de = ext2_dotdot(old_inode, &dir_folio); 351 if (!dir_de) 352 goto out_old; 353 } 354 355 if (new_inode) { 356 struct folio *new_folio; 357 struct ext2_dir_entry_2 *new_de; 358 359 err = -ENOTEMPTY; 360 if (old_is_dir && !ext2_empty_dir(new_inode)) 361 goto out_dir; 362 363 new_de = ext2_find_entry(new_dir, &new_dentry->d_name, 364 &new_folio); 365 if (IS_ERR(new_de)) { 366 err = PTR_ERR(new_de); 367 goto out_dir; 368 } 369 err = ext2_set_link(new_dir, new_de, new_folio, old_inode, true); 370 folio_release_kmap(new_folio, new_de); 371 if (err) 372 goto out_dir; 373 inode_set_ctime_current(new_inode); 374 if (old_is_dir) 375 drop_nlink(new_inode); 376 inode_dec_link_count(new_inode); 377 } else { 378 err = ext2_add_link(new_dentry, old_inode); 379 if (err) 380 goto out_dir; 381 if (old_is_dir) 382 inode_inc_link_count(new_dir); 383 } 384 385 /* 386 * Like most other Unix systems, set the ctime for inodes on a 387 * rename. 388 */ 389 inode_set_ctime_current(old_inode); 390 mark_inode_dirty(old_inode); 391 392 err = ext2_delete_entry(old_de, old_folio); 393 if (!err && old_is_dir) { 394 if (old_dir != new_dir) 395 err = ext2_set_link(old_inode, dir_de, dir_folio, 396 new_dir, false); 397 398 inode_dec_link_count(old_dir); 399 } 400 out_dir: 401 if (dir_de) 402 folio_release_kmap(dir_folio, dir_de); 403 out_old: 404 folio_release_kmap(old_folio, old_de); 405 return err; 406 } 407 408 const struct inode_operations ext2_dir_inode_operations = { 409 .create = ext2_create, 410 .lookup = ext2_lookup, 411 .link = ext2_link, 412 .unlink = ext2_unlink, 413 .symlink = ext2_symlink, 414 .mkdir = ext2_mkdir, 415 .rmdir = ext2_rmdir, 416 .mknod = ext2_mknod, 417 .rename = ext2_rename, 418 .listxattr = ext2_listxattr, 419 .getattr = ext2_getattr, 420 .setattr = ext2_setattr, 421 .get_inode_acl = ext2_get_acl, 422 .set_acl = ext2_set_acl, 423 .tmpfile = ext2_tmpfile, 424 .fileattr_get = ext2_fileattr_get, 425 .fileattr_set = ext2_fileattr_set, 426 }; 427 428 const struct inode_operations ext2_special_inode_operations = { 429 .listxattr = ext2_listxattr, 430 .getattr = ext2_getattr, 431 .setattr = ext2_setattr, 432 .get_inode_acl = ext2_get_acl, 433 .set_acl = ext2_set_acl, 434 }; 435