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 struct qstr dotdot = QSTR_INIT("..", 2); 85 ino_t ino; 86 int res; 87 88 res = ext2_inode_by_name(d_inode(child), &dotdot, &ino); 89 if (res) 90 return ERR_PTR(res); 91 92 return d_obtain_alias(ext2_iget(child->d_sb, ino)); 93 } 94 95 /* 96 * By the time this is called, we already have created 97 * the directory cache entry for the new file, but it 98 * is so far negative - it has no inode. 99 * 100 * If the create succeeds, we fill in the inode information 101 * with d_instantiate(). 102 */ 103 static int ext2_create (struct user_namespace * mnt_userns, 104 struct inode * dir, struct dentry * dentry, 105 umode_t mode, bool excl) 106 { 107 struct inode *inode; 108 int err; 109 110 err = dquot_initialize(dir); 111 if (err) 112 return err; 113 114 inode = ext2_new_inode(dir, mode, &dentry->d_name); 115 if (IS_ERR(inode)) 116 return PTR_ERR(inode); 117 118 ext2_set_file_ops(inode); 119 mark_inode_dirty(inode); 120 return ext2_add_nondir(dentry, inode); 121 } 122 123 static int ext2_tmpfile(struct user_namespace *mnt_userns, struct inode *dir, 124 struct dentry *dentry, umode_t mode) 125 { 126 struct inode *inode = ext2_new_inode(dir, mode, NULL); 127 if (IS_ERR(inode)) 128 return PTR_ERR(inode); 129 130 ext2_set_file_ops(inode); 131 mark_inode_dirty(inode); 132 d_tmpfile(dentry, inode); 133 unlock_new_inode(inode); 134 return 0; 135 } 136 137 static int ext2_mknod (struct user_namespace * mnt_userns, struct inode * dir, 138 struct dentry *dentry, umode_t mode, dev_t rdev) 139 { 140 struct inode * inode; 141 int err; 142 143 err = dquot_initialize(dir); 144 if (err) 145 return err; 146 147 inode = ext2_new_inode (dir, mode, &dentry->d_name); 148 err = PTR_ERR(inode); 149 if (!IS_ERR(inode)) { 150 init_special_inode(inode, inode->i_mode, rdev); 151 inode->i_op = &ext2_special_inode_operations; 152 mark_inode_dirty(inode); 153 err = ext2_add_nondir(dentry, inode); 154 } 155 return err; 156 } 157 158 static int ext2_symlink (struct user_namespace * mnt_userns, struct inode * dir, 159 struct dentry * dentry, const char * symname) 160 { 161 struct super_block * sb = dir->i_sb; 162 int err = -ENAMETOOLONG; 163 unsigned l = strlen(symname)+1; 164 struct inode * inode; 165 166 if (l > sb->s_blocksize) 167 goto out; 168 169 err = dquot_initialize(dir); 170 if (err) 171 goto out; 172 173 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name); 174 err = PTR_ERR(inode); 175 if (IS_ERR(inode)) 176 goto out; 177 178 if (l > sizeof (EXT2_I(inode)->i_data)) { 179 /* slow symlink */ 180 inode->i_op = &ext2_symlink_inode_operations; 181 inode_nohighmem(inode); 182 if (test_opt(inode->i_sb, NOBH)) 183 inode->i_mapping->a_ops = &ext2_nobh_aops; 184 else 185 inode->i_mapping->a_ops = &ext2_aops; 186 err = page_symlink(inode, symname, l); 187 if (err) 188 goto out_fail; 189 } else { 190 /* fast symlink */ 191 inode->i_op = &ext2_fast_symlink_inode_operations; 192 inode->i_link = (char*)EXT2_I(inode)->i_data; 193 memcpy(inode->i_link, symname, l); 194 inode->i_size = l-1; 195 } 196 mark_inode_dirty(inode); 197 198 err = ext2_add_nondir(dentry, inode); 199 out: 200 return err; 201 202 out_fail: 203 inode_dec_link_count(inode); 204 discard_new_inode(inode); 205 goto out; 206 } 207 208 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 209 struct dentry *dentry) 210 { 211 struct inode *inode = d_inode(old_dentry); 212 int err; 213 214 err = dquot_initialize(dir); 215 if (err) 216 return err; 217 218 inode->i_ctime = current_time(inode); 219 inode_inc_link_count(inode); 220 ihold(inode); 221 222 err = ext2_add_link(dentry, inode); 223 if (!err) { 224 d_instantiate(dentry, inode); 225 return 0; 226 } 227 inode_dec_link_count(inode); 228 iput(inode); 229 return err; 230 } 231 232 static int ext2_mkdir(struct user_namespace * mnt_userns, 233 struct inode * dir, struct dentry * dentry, umode_t mode) 234 { 235 struct inode * inode; 236 int err; 237 238 err = dquot_initialize(dir); 239 if (err) 240 return err; 241 242 inode_inc_link_count(dir); 243 244 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 245 err = PTR_ERR(inode); 246 if (IS_ERR(inode)) 247 goto out_dir; 248 249 inode->i_op = &ext2_dir_inode_operations; 250 inode->i_fop = &ext2_dir_operations; 251 if (test_opt(inode->i_sb, NOBH)) 252 inode->i_mapping->a_ops = &ext2_nobh_aops; 253 else 254 inode->i_mapping->a_ops = &ext2_aops; 255 256 inode_inc_link_count(inode); 257 258 err = ext2_make_empty(inode, dir); 259 if (err) 260 goto out_fail; 261 262 err = ext2_add_link(dentry, inode); 263 if (err) 264 goto out_fail; 265 266 d_instantiate_new(dentry, inode); 267 out: 268 return err; 269 270 out_fail: 271 inode_dec_link_count(inode); 272 inode_dec_link_count(inode); 273 discard_new_inode(inode); 274 out_dir: 275 inode_dec_link_count(dir); 276 goto out; 277 } 278 279 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 280 { 281 struct inode * inode = d_inode(dentry); 282 struct ext2_dir_entry_2 * de; 283 struct page * page; 284 void *page_addr; 285 int err; 286 287 err = dquot_initialize(dir); 288 if (err) 289 goto out; 290 291 de = ext2_find_entry(dir, &dentry->d_name, &page, &page_addr); 292 if (IS_ERR(de)) { 293 err = PTR_ERR(de); 294 goto out; 295 } 296 297 err = ext2_delete_entry (de, page); 298 ext2_put_page(page, page_addr); 299 if (err) 300 goto out; 301 302 inode->i_ctime = dir->i_ctime; 303 inode_dec_link_count(inode); 304 err = 0; 305 out: 306 return err; 307 } 308 309 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 310 { 311 struct inode * inode = d_inode(dentry); 312 int err = -ENOTEMPTY; 313 314 if (ext2_empty_dir(inode)) { 315 err = ext2_unlink(dir, dentry); 316 if (!err) { 317 inode->i_size = 0; 318 inode_dec_link_count(inode); 319 inode_dec_link_count(dir); 320 } 321 } 322 return err; 323 } 324 325 static int ext2_rename (struct user_namespace * mnt_userns, 326 struct inode * old_dir, struct dentry * old_dentry, 327 struct inode * new_dir, struct dentry * new_dentry, 328 unsigned int flags) 329 { 330 struct inode * old_inode = d_inode(old_dentry); 331 struct inode * new_inode = d_inode(new_dentry); 332 struct page * dir_page = NULL; 333 void *dir_page_addr; 334 struct ext2_dir_entry_2 * dir_de = NULL; 335 struct page * old_page; 336 void *old_page_addr; 337 struct ext2_dir_entry_2 * old_de; 338 int err; 339 340 if (flags & ~RENAME_NOREPLACE) 341 return -EINVAL; 342 343 err = dquot_initialize(old_dir); 344 if (err) 345 goto out; 346 347 err = dquot_initialize(new_dir); 348 if (err) 349 goto out; 350 351 old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_page, 352 &old_page_addr); 353 if (IS_ERR(old_de)) { 354 err = PTR_ERR(old_de); 355 goto out; 356 } 357 358 if (S_ISDIR(old_inode->i_mode)) { 359 err = -EIO; 360 dir_de = ext2_dotdot(old_inode, &dir_page, &dir_page_addr); 361 if (!dir_de) 362 goto out_old; 363 } 364 365 if (new_inode) { 366 void *page_addr; 367 struct page *new_page; 368 struct ext2_dir_entry_2 *new_de; 369 370 err = -ENOTEMPTY; 371 if (dir_de && !ext2_empty_dir (new_inode)) 372 goto out_dir; 373 374 new_de = ext2_find_entry(new_dir, &new_dentry->d_name, 375 &new_page, &page_addr); 376 if (IS_ERR(new_de)) { 377 err = PTR_ERR(new_de); 378 goto out_dir; 379 } 380 ext2_set_link(new_dir, new_de, new_page, page_addr, old_inode, 1); 381 ext2_put_page(new_page, page_addr); 382 new_inode->i_ctime = current_time(new_inode); 383 if (dir_de) 384 drop_nlink(new_inode); 385 inode_dec_link_count(new_inode); 386 } else { 387 err = ext2_add_link(new_dentry, old_inode); 388 if (err) 389 goto out_dir; 390 if (dir_de) 391 inode_inc_link_count(new_dir); 392 } 393 394 /* 395 * Like most other Unix systems, set the ctime for inodes on a 396 * rename. 397 */ 398 old_inode->i_ctime = current_time(old_inode); 399 mark_inode_dirty(old_inode); 400 401 ext2_delete_entry(old_de, old_page); 402 403 if (dir_de) { 404 if (old_dir != new_dir) 405 ext2_set_link(old_inode, dir_de, dir_page, 406 dir_page_addr, new_dir, 0); 407 408 ext2_put_page(dir_page, dir_page_addr); 409 inode_dec_link_count(old_dir); 410 } 411 412 ext2_put_page(old_page, old_page_addr); 413 return 0; 414 415 out_dir: 416 if (dir_de) 417 ext2_put_page(dir_page, dir_page_addr); 418 out_old: 419 ext2_put_page(old_page, old_page_addr); 420 out: 421 return err; 422 } 423 424 const struct inode_operations ext2_dir_inode_operations = { 425 .create = ext2_create, 426 .lookup = ext2_lookup, 427 .link = ext2_link, 428 .unlink = ext2_unlink, 429 .symlink = ext2_symlink, 430 .mkdir = ext2_mkdir, 431 .rmdir = ext2_rmdir, 432 .mknod = ext2_mknod, 433 .rename = ext2_rename, 434 .listxattr = ext2_listxattr, 435 .getattr = ext2_getattr, 436 .setattr = ext2_setattr, 437 .get_acl = ext2_get_acl, 438 .set_acl = ext2_set_acl, 439 .tmpfile = ext2_tmpfile, 440 .fileattr_get = ext2_fileattr_get, 441 .fileattr_set = ext2_fileattr_set, 442 }; 443 444 const struct inode_operations ext2_special_inode_operations = { 445 .listxattr = ext2_listxattr, 446 .getattr = ext2_getattr, 447 .setattr = ext2_setattr, 448 .get_acl = ext2_get_acl, 449 .set_acl = ext2_set_acl, 450 }; 451