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 discard_new_inode(inode); 49 return err; 50 } 51 52 /* 53 * Methods themselves. 54 */ 55 56 static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, unsigned int flags) 57 { 58 struct inode * inode; 59 ino_t ino; 60 int res; 61 62 if (dentry->d_name.len > EXT2_NAME_LEN) 63 return ERR_PTR(-ENAMETOOLONG); 64 65 res = ext2_inode_by_name(dir, &dentry->d_name, &ino); 66 if (res) { 67 if (res != -ENOENT) 68 return ERR_PTR(res); 69 inode = NULL; 70 } else { 71 inode = ext2_iget(dir->i_sb, ino); 72 if (inode == ERR_PTR(-ESTALE)) { 73 ext2_error(dir->i_sb, __func__, 74 "deleted inode referenced: %lu", 75 (unsigned long) ino); 76 return ERR_PTR(-EIO); 77 } 78 } 79 return d_splice_alias(inode, dentry); 80 } 81 82 struct dentry *ext2_get_parent(struct dentry *child) 83 { 84 ino_t ino; 85 int res; 86 87 res = ext2_inode_by_name(d_inode(child), &dotdot_name, &ino); 88 if (res) 89 return ERR_PTR(res); 90 91 return d_obtain_alias(ext2_iget(child->d_sb, ino)); 92 } 93 94 /* 95 * By the time this is called, we already have created 96 * the directory cache entry for the new file, but it 97 * is so far negative - it has no inode. 98 * 99 * If the create succeeds, we fill in the inode information 100 * with d_instantiate(). 101 */ 102 static int ext2_create (struct mnt_idmap * idmap, 103 struct inode * dir, struct dentry * dentry, 104 umode_t mode, bool excl) 105 { 106 struct inode *inode; 107 int err; 108 109 err = dquot_initialize(dir); 110 if (err) 111 return err; 112 113 inode = ext2_new_inode(dir, mode, &dentry->d_name); 114 if (IS_ERR(inode)) 115 return PTR_ERR(inode); 116 117 ext2_set_file_ops(inode); 118 mark_inode_dirty(inode); 119 return ext2_add_nondir(dentry, inode); 120 } 121 122 static int ext2_tmpfile(struct mnt_idmap *idmap, struct inode *dir, 123 struct file *file, umode_t mode) 124 { 125 struct inode *inode = ext2_new_inode(dir, mode, NULL); 126 if (IS_ERR(inode)) 127 return PTR_ERR(inode); 128 129 ext2_set_file_ops(inode); 130 mark_inode_dirty(inode); 131 d_tmpfile(file, inode); 132 unlock_new_inode(inode); 133 return finish_open_simple(file, 0); 134 } 135 136 static int ext2_mknod (struct mnt_idmap * idmap, struct inode * dir, 137 struct dentry *dentry, umode_t mode, dev_t rdev) 138 { 139 struct inode * inode; 140 int err; 141 142 err = dquot_initialize(dir); 143 if (err) 144 return err; 145 146 inode = ext2_new_inode (dir, mode, &dentry->d_name); 147 err = PTR_ERR(inode); 148 if (!IS_ERR(inode)) { 149 init_special_inode(inode, inode->i_mode, rdev); 150 inode->i_op = &ext2_special_inode_operations; 151 mark_inode_dirty(inode); 152 err = ext2_add_nondir(dentry, inode); 153 } 154 return err; 155 } 156 157 static int ext2_symlink (struct mnt_idmap * idmap, struct inode * dir, 158 struct dentry * dentry, const char * symname) 159 { 160 struct super_block * sb = dir->i_sb; 161 int err = -ENAMETOOLONG; 162 unsigned l = strlen(symname)+1; 163 struct inode * inode; 164 165 if (l > sb->s_blocksize) 166 goto out; 167 168 err = dquot_initialize(dir); 169 if (err) 170 goto out; 171 172 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name); 173 err = PTR_ERR(inode); 174 if (IS_ERR(inode)) 175 goto out; 176 177 if (l > sizeof (EXT2_I(inode)->i_data)) { 178 /* slow symlink */ 179 inode->i_op = &ext2_symlink_inode_operations; 180 inode_nohighmem(inode); 181 inode->i_mapping->a_ops = &ext2_aops; 182 err = page_symlink(inode, symname, l); 183 if (err) 184 goto out_fail; 185 } else { 186 /* fast symlink */ 187 inode->i_op = &ext2_fast_symlink_inode_operations; 188 inode->i_link = (char*)EXT2_I(inode)->i_data; 189 memcpy(inode->i_link, symname, l); 190 inode->i_size = l-1; 191 } 192 mark_inode_dirty(inode); 193 194 err = ext2_add_nondir(dentry, inode); 195 out: 196 return err; 197 198 out_fail: 199 inode_dec_link_count(inode); 200 discard_new_inode(inode); 201 goto out; 202 } 203 204 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 205 struct dentry *dentry) 206 { 207 struct inode *inode = d_inode(old_dentry); 208 int err; 209 210 err = dquot_initialize(dir); 211 if (err) 212 return err; 213 214 inode_set_ctime_current(inode); 215 inode_inc_link_count(inode); 216 ihold(inode); 217 218 err = ext2_add_link(dentry, inode); 219 if (!err) { 220 d_instantiate(dentry, inode); 221 return 0; 222 } 223 inode_dec_link_count(inode); 224 iput(inode); 225 return err; 226 } 227 228 static int ext2_mkdir(struct mnt_idmap * idmap, 229 struct inode * dir, struct dentry * dentry, umode_t mode) 230 { 231 struct inode * inode; 232 int err; 233 234 err = dquot_initialize(dir); 235 if (err) 236 return err; 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 inode->i_mapping->a_ops = &ext2_aops; 248 249 inode_inc_link_count(inode); 250 251 err = ext2_make_empty(inode, dir); 252 if (err) 253 goto out_fail; 254 255 err = ext2_add_link(dentry, inode); 256 if (err) 257 goto out_fail; 258 259 d_instantiate_new(dentry, inode); 260 out: 261 return err; 262 263 out_fail: 264 inode_dec_link_count(inode); 265 inode_dec_link_count(inode); 266 discard_new_inode(inode); 267 out_dir: 268 inode_dec_link_count(dir); 269 goto out; 270 } 271 272 static int ext2_unlink(struct inode *dir, struct dentry *dentry) 273 { 274 struct inode *inode = d_inode(dentry); 275 struct ext2_dir_entry_2 *de; 276 struct folio *folio; 277 int err; 278 279 err = dquot_initialize(dir); 280 if (err) 281 goto out; 282 283 de = ext2_find_entry(dir, &dentry->d_name, &folio); 284 if (IS_ERR(de)) { 285 err = PTR_ERR(de); 286 goto out; 287 } 288 289 err = ext2_delete_entry(de, folio); 290 folio_release_kmap(folio, de); 291 if (err) 292 goto out; 293 294 inode_set_ctime_to_ts(inode, inode_get_ctime(dir)); 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 mnt_idmap * idmap, 318 struct inode * old_dir, struct dentry * old_dentry, 319 struct inode * new_dir, struct dentry * new_dentry, 320 unsigned int flags) 321 { 322 struct inode * old_inode = d_inode(old_dentry); 323 struct inode * new_inode = d_inode(new_dentry); 324 struct folio *dir_folio = NULL; 325 struct ext2_dir_entry_2 * dir_de = NULL; 326 struct folio * old_folio; 327 struct ext2_dir_entry_2 * old_de; 328 bool old_is_dir = S_ISDIR(old_inode->i_mode); 329 int err; 330 331 if (flags & ~RENAME_NOREPLACE) 332 return -EINVAL; 333 334 err = dquot_initialize(old_dir); 335 if (err) 336 return err; 337 338 err = dquot_initialize(new_dir); 339 if (err) 340 return err; 341 342 old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_folio); 343 if (IS_ERR(old_de)) 344 return PTR_ERR(old_de); 345 346 if (old_is_dir && old_dir != new_dir) { 347 err = -EIO; 348 dir_de = ext2_dotdot(old_inode, &dir_folio); 349 if (!dir_de) 350 goto out_old; 351 } 352 353 if (new_inode) { 354 struct folio *new_folio; 355 struct ext2_dir_entry_2 *new_de; 356 357 err = -ENOTEMPTY; 358 if (old_is_dir && !ext2_empty_dir(new_inode)) 359 goto out_dir; 360 361 new_de = ext2_find_entry(new_dir, &new_dentry->d_name, 362 &new_folio); 363 if (IS_ERR(new_de)) { 364 err = PTR_ERR(new_de); 365 goto out_dir; 366 } 367 err = ext2_set_link(new_dir, new_de, new_folio, old_inode, true); 368 folio_release_kmap(new_folio, new_de); 369 if (err) 370 goto out_dir; 371 inode_set_ctime_current(new_inode); 372 if (old_is_dir) 373 drop_nlink(new_inode); 374 inode_dec_link_count(new_inode); 375 } else { 376 err = ext2_add_link(new_dentry, old_inode); 377 if (err) 378 goto out_dir; 379 if (old_is_dir) 380 inode_inc_link_count(new_dir); 381 } 382 383 /* 384 * Like most other Unix systems, set the ctime for inodes on a 385 * rename. 386 */ 387 inode_set_ctime_current(old_inode); 388 mark_inode_dirty(old_inode); 389 390 err = ext2_delete_entry(old_de, old_folio); 391 if (!err && old_is_dir) { 392 if (old_dir != new_dir) 393 err = ext2_set_link(old_inode, dir_de, dir_folio, 394 new_dir, false); 395 396 inode_dec_link_count(old_dir); 397 } 398 out_dir: 399 if (dir_de) 400 folio_release_kmap(dir_folio, dir_de); 401 out_old: 402 folio_release_kmap(old_folio, old_de); 403 return err; 404 } 405 406 const struct inode_operations ext2_dir_inode_operations = { 407 .create = ext2_create, 408 .lookup = ext2_lookup, 409 .link = ext2_link, 410 .unlink = ext2_unlink, 411 .symlink = ext2_symlink, 412 .mkdir = ext2_mkdir, 413 .rmdir = ext2_rmdir, 414 .mknod = ext2_mknod, 415 .rename = ext2_rename, 416 .listxattr = ext2_listxattr, 417 .getattr = ext2_getattr, 418 .setattr = ext2_setattr, 419 .get_inode_acl = ext2_get_acl, 420 .set_acl = ext2_set_acl, 421 .tmpfile = ext2_tmpfile, 422 .fileattr_get = ext2_fileattr_get, 423 .fileattr_set = ext2_fileattr_set, 424 }; 425 426 const struct inode_operations ext2_special_inode_operations = { 427 .listxattr = ext2_listxattr, 428 .getattr = ext2_getattr, 429 .setattr = ext2_setattr, 430 .get_inode_acl = ext2_get_acl, 431 .set_acl = ext2_set_acl, 432 }; 433