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 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->i_ctime = current_time(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 user_namespace * mnt_userns, 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 page * page; 277 void *page_addr; 278 int err; 279 280 err = dquot_initialize(dir); 281 if (err) 282 goto out; 283 284 de = ext2_find_entry(dir, &dentry->d_name, &page, &page_addr); 285 if (IS_ERR(de)) { 286 err = PTR_ERR(de); 287 goto out; 288 } 289 290 err = ext2_delete_entry (de, page, page_addr); 291 ext2_put_page(page, page_addr); 292 if (err) 293 goto out; 294 295 inode->i_ctime = dir->i_ctime; 296 inode_dec_link_count(inode); 297 err = 0; 298 out: 299 return err; 300 } 301 302 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 303 { 304 struct inode * inode = d_inode(dentry); 305 int err = -ENOTEMPTY; 306 307 if (ext2_empty_dir(inode)) { 308 err = ext2_unlink(dir, dentry); 309 if (!err) { 310 inode->i_size = 0; 311 inode_dec_link_count(inode); 312 inode_dec_link_count(dir); 313 } 314 } 315 return err; 316 } 317 318 static int ext2_rename (struct user_namespace * mnt_userns, 319 struct inode * old_dir, struct dentry * old_dentry, 320 struct inode * new_dir, struct dentry * new_dentry, 321 unsigned int flags) 322 { 323 struct inode * old_inode = d_inode(old_dentry); 324 struct inode * new_inode = d_inode(new_dentry); 325 struct page * dir_page = NULL; 326 void *dir_page_addr; 327 struct ext2_dir_entry_2 * dir_de = NULL; 328 struct page * old_page; 329 void *old_page_addr; 330 struct ext2_dir_entry_2 * old_de; 331 int err; 332 333 if (flags & ~RENAME_NOREPLACE) 334 return -EINVAL; 335 336 err = dquot_initialize(old_dir); 337 if (err) 338 goto out; 339 340 err = dquot_initialize(new_dir); 341 if (err) 342 goto out; 343 344 old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_page, 345 &old_page_addr); 346 if (IS_ERR(old_de)) { 347 err = PTR_ERR(old_de); 348 goto out; 349 } 350 351 if (S_ISDIR(old_inode->i_mode)) { 352 err = -EIO; 353 dir_de = ext2_dotdot(old_inode, &dir_page, &dir_page_addr); 354 if (!dir_de) 355 goto out_old; 356 } 357 358 if (new_inode) { 359 void *page_addr; 360 struct page *new_page; 361 struct ext2_dir_entry_2 *new_de; 362 363 err = -ENOTEMPTY; 364 if (dir_de && !ext2_empty_dir (new_inode)) 365 goto out_dir; 366 367 new_de = ext2_find_entry(new_dir, &new_dentry->d_name, 368 &new_page, &page_addr); 369 if (IS_ERR(new_de)) { 370 err = PTR_ERR(new_de); 371 goto out_dir; 372 } 373 ext2_set_link(new_dir, new_de, new_page, page_addr, old_inode, 1); 374 ext2_put_page(new_page, page_addr); 375 new_inode->i_ctime = current_time(new_inode); 376 if (dir_de) 377 drop_nlink(new_inode); 378 inode_dec_link_count(new_inode); 379 } else { 380 err = ext2_add_link(new_dentry, old_inode); 381 if (err) 382 goto out_dir; 383 if (dir_de) 384 inode_inc_link_count(new_dir); 385 } 386 387 /* 388 * Like most other Unix systems, set the ctime for inodes on a 389 * rename. 390 */ 391 old_inode->i_ctime = current_time(old_inode); 392 mark_inode_dirty(old_inode); 393 394 ext2_delete_entry(old_de, old_page, old_page_addr); 395 396 if (dir_de) { 397 if (old_dir != new_dir) 398 ext2_set_link(old_inode, dir_de, dir_page, 399 dir_page_addr, new_dir, 0); 400 401 ext2_put_page(dir_page, dir_page_addr); 402 inode_dec_link_count(old_dir); 403 } 404 405 ext2_put_page(old_page, old_page_addr); 406 return 0; 407 408 out_dir: 409 if (dir_de) 410 ext2_put_page(dir_page, dir_page_addr); 411 out_old: 412 ext2_put_page(old_page, old_page_addr); 413 out: 414 return err; 415 } 416 417 const struct inode_operations ext2_dir_inode_operations = { 418 .create = ext2_create, 419 .lookup = ext2_lookup, 420 .link = ext2_link, 421 .unlink = ext2_unlink, 422 .symlink = ext2_symlink, 423 .mkdir = ext2_mkdir, 424 .rmdir = ext2_rmdir, 425 .mknod = ext2_mknod, 426 .rename = ext2_rename, 427 .listxattr = ext2_listxattr, 428 .getattr = ext2_getattr, 429 .setattr = ext2_setattr, 430 .get_acl = ext2_get_acl, 431 .set_acl = ext2_set_acl, 432 .tmpfile = ext2_tmpfile, 433 .fileattr_get = ext2_fileattr_get, 434 .fileattr_set = ext2_fileattr_set, 435 }; 436 437 const struct inode_operations ext2_special_inode_operations = { 438 .listxattr = ext2_listxattr, 439 .getattr = ext2_getattr, 440 .setattr = ext2_setattr, 441 .get_acl = ext2_get_acl, 442 .set_acl = ext2_set_acl, 443 }; 444