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 user_namespace * mnt_userns, 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 user_namespace *mnt_userns, struct inode *dir, 123 struct dentry *dentry, 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(dentry, inode); 132 unlock_new_inode(inode); 133 return 0; 134 } 135 136 static int ext2_mknod (struct user_namespace * mnt_userns, 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 user_namespace * mnt_userns, 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 if (test_opt(inode->i_sb, NOBH)) 182 inode->i_mapping->a_ops = &ext2_nobh_aops; 183 else 184 inode->i_mapping->a_ops = &ext2_aops; 185 err = page_symlink(inode, symname, l); 186 if (err) 187 goto out_fail; 188 } else { 189 /* fast symlink */ 190 inode->i_op = &ext2_fast_symlink_inode_operations; 191 inode->i_link = (char*)EXT2_I(inode)->i_data; 192 memcpy(inode->i_link, symname, l); 193 inode->i_size = l-1; 194 } 195 mark_inode_dirty(inode); 196 197 err = ext2_add_nondir(dentry, inode); 198 out: 199 return err; 200 201 out_fail: 202 inode_dec_link_count(inode); 203 discard_new_inode(inode); 204 goto out; 205 } 206 207 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 208 struct dentry *dentry) 209 { 210 struct inode *inode = d_inode(old_dentry); 211 int err; 212 213 err = dquot_initialize(dir); 214 if (err) 215 return err; 216 217 inode->i_ctime = current_time(inode); 218 inode_inc_link_count(inode); 219 ihold(inode); 220 221 err = ext2_add_link(dentry, inode); 222 if (!err) { 223 d_instantiate(dentry, inode); 224 return 0; 225 } 226 inode_dec_link_count(inode); 227 iput(inode); 228 return err; 229 } 230 231 static int ext2_mkdir(struct user_namespace * mnt_userns, 232 struct inode * dir, struct dentry * dentry, umode_t mode) 233 { 234 struct inode * inode; 235 int err; 236 237 err = dquot_initialize(dir); 238 if (err) 239 return err; 240 241 inode_inc_link_count(dir); 242 243 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 244 err = PTR_ERR(inode); 245 if (IS_ERR(inode)) 246 goto out_dir; 247 248 inode->i_op = &ext2_dir_inode_operations; 249 inode->i_fop = &ext2_dir_operations; 250 if (test_opt(inode->i_sb, NOBH)) 251 inode->i_mapping->a_ops = &ext2_nobh_aops; 252 else 253 inode->i_mapping->a_ops = &ext2_aops; 254 255 inode_inc_link_count(inode); 256 257 err = ext2_make_empty(inode, dir); 258 if (err) 259 goto out_fail; 260 261 err = ext2_add_link(dentry, inode); 262 if (err) 263 goto out_fail; 264 265 d_instantiate_new(dentry, inode); 266 out: 267 return err; 268 269 out_fail: 270 inode_dec_link_count(inode); 271 inode_dec_link_count(inode); 272 discard_new_inode(inode); 273 out_dir: 274 inode_dec_link_count(dir); 275 goto out; 276 } 277 278 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 279 { 280 struct inode * inode = d_inode(dentry); 281 struct ext2_dir_entry_2 * de; 282 struct page * page; 283 void *page_addr; 284 int err; 285 286 err = dquot_initialize(dir); 287 if (err) 288 goto out; 289 290 de = ext2_find_entry(dir, &dentry->d_name, &page, &page_addr); 291 if (IS_ERR(de)) { 292 err = PTR_ERR(de); 293 goto out; 294 } 295 296 err = ext2_delete_entry (de, page, page_addr); 297 ext2_put_page(page, page_addr); 298 if (err) 299 goto out; 300 301 inode->i_ctime = dir->i_ctime; 302 inode_dec_link_count(inode); 303 err = 0; 304 out: 305 return err; 306 } 307 308 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 309 { 310 struct inode * inode = d_inode(dentry); 311 int err = -ENOTEMPTY; 312 313 if (ext2_empty_dir(inode)) { 314 err = ext2_unlink(dir, dentry); 315 if (!err) { 316 inode->i_size = 0; 317 inode_dec_link_count(inode); 318 inode_dec_link_count(dir); 319 } 320 } 321 return err; 322 } 323 324 static int ext2_rename (struct user_namespace * mnt_userns, 325 struct inode * old_dir, struct dentry * old_dentry, 326 struct inode * new_dir, struct dentry * new_dentry, 327 unsigned int flags) 328 { 329 struct inode * old_inode = d_inode(old_dentry); 330 struct inode * new_inode = d_inode(new_dentry); 331 struct page * dir_page = NULL; 332 void *dir_page_addr; 333 struct ext2_dir_entry_2 * dir_de = NULL; 334 struct page * old_page; 335 void *old_page_addr; 336 struct ext2_dir_entry_2 * old_de; 337 int err; 338 339 if (flags & ~RENAME_NOREPLACE) 340 return -EINVAL; 341 342 err = dquot_initialize(old_dir); 343 if (err) 344 goto out; 345 346 err = dquot_initialize(new_dir); 347 if (err) 348 goto out; 349 350 old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_page, 351 &old_page_addr); 352 if (IS_ERR(old_de)) { 353 err = PTR_ERR(old_de); 354 goto out; 355 } 356 357 if (S_ISDIR(old_inode->i_mode)) { 358 err = -EIO; 359 dir_de = ext2_dotdot(old_inode, &dir_page, &dir_page_addr); 360 if (!dir_de) 361 goto out_old; 362 } 363 364 if (new_inode) { 365 void *page_addr; 366 struct page *new_page; 367 struct ext2_dir_entry_2 *new_de; 368 369 err = -ENOTEMPTY; 370 if (dir_de && !ext2_empty_dir (new_inode)) 371 goto out_dir; 372 373 new_de = ext2_find_entry(new_dir, &new_dentry->d_name, 374 &new_page, &page_addr); 375 if (IS_ERR(new_de)) { 376 err = PTR_ERR(new_de); 377 goto out_dir; 378 } 379 ext2_set_link(new_dir, new_de, new_page, page_addr, old_inode, 1); 380 ext2_put_page(new_page, page_addr); 381 new_inode->i_ctime = current_time(new_inode); 382 if (dir_de) 383 drop_nlink(new_inode); 384 inode_dec_link_count(new_inode); 385 } else { 386 err = ext2_add_link(new_dentry, old_inode); 387 if (err) 388 goto out_dir; 389 if (dir_de) 390 inode_inc_link_count(new_dir); 391 } 392 393 /* 394 * Like most other Unix systems, set the ctime for inodes on a 395 * rename. 396 */ 397 old_inode->i_ctime = current_time(old_inode); 398 mark_inode_dirty(old_inode); 399 400 ext2_delete_entry(old_de, old_page, old_page_addr); 401 402 if (dir_de) { 403 if (old_dir != new_dir) 404 ext2_set_link(old_inode, dir_de, dir_page, 405 dir_page_addr, new_dir, 0); 406 407 ext2_put_page(dir_page, dir_page_addr); 408 inode_dec_link_count(old_dir); 409 } 410 411 ext2_put_page(old_page, old_page_addr); 412 return 0; 413 414 out_dir: 415 if (dir_de) 416 ext2_put_page(dir_page, dir_page_addr); 417 out_old: 418 ext2_put_page(old_page, old_page_addr); 419 out: 420 return err; 421 } 422 423 const struct inode_operations ext2_dir_inode_operations = { 424 .create = ext2_create, 425 .lookup = ext2_lookup, 426 .link = ext2_link, 427 .unlink = ext2_unlink, 428 .symlink = ext2_symlink, 429 .mkdir = ext2_mkdir, 430 .rmdir = ext2_rmdir, 431 .mknod = ext2_mknod, 432 .rename = ext2_rename, 433 .listxattr = ext2_listxattr, 434 .getattr = ext2_getattr, 435 .setattr = ext2_setattr, 436 .get_acl = ext2_get_acl, 437 .set_acl = ext2_set_acl, 438 .tmpfile = ext2_tmpfile, 439 .fileattr_get = ext2_fileattr_get, 440 .fileattr_set = ext2_fileattr_set, 441 }; 442 443 const struct inode_operations ext2_special_inode_operations = { 444 .listxattr = ext2_listxattr, 445 .getattr = ext2_getattr, 446 .setattr = ext2_setattr, 447 .get_acl = ext2_get_acl, 448 .set_acl = ext2_set_acl, 449 }; 450