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 61 if (dentry->d_name.len > EXT2_NAME_LEN) 62 return ERR_PTR(-ENAMETOOLONG); 63 64 ino = ext2_inode_by_name(dir, &dentry->d_name); 65 inode = NULL; 66 if (ino) { 67 inode = ext2_iget(dir->i_sb, ino); 68 if (inode == ERR_PTR(-ESTALE)) { 69 ext2_error(dir->i_sb, __func__, 70 "deleted inode referenced: %lu", 71 (unsigned long) ino); 72 return ERR_PTR(-EIO); 73 } 74 } 75 return d_splice_alias(inode, dentry); 76 } 77 78 struct dentry *ext2_get_parent(struct dentry *child) 79 { 80 struct qstr dotdot = QSTR_INIT("..", 2); 81 unsigned long ino = ext2_inode_by_name(d_inode(child), &dotdot); 82 if (!ino) 83 return ERR_PTR(-ENOENT); 84 return d_obtain_alias(ext2_iget(child->d_sb, ino)); 85 } 86 87 /* 88 * By the time this is called, we already have created 89 * the directory cache entry for the new file, but it 90 * is so far negative - it has no inode. 91 * 92 * If the create succeeds, we fill in the inode information 93 * with d_instantiate(). 94 */ 95 static int ext2_create (struct inode * dir, struct dentry * dentry, umode_t mode, bool excl) 96 { 97 struct inode *inode; 98 int err; 99 100 err = dquot_initialize(dir); 101 if (err) 102 return err; 103 104 inode = ext2_new_inode(dir, mode, &dentry->d_name); 105 if (IS_ERR(inode)) 106 return PTR_ERR(inode); 107 108 ext2_set_file_ops(inode); 109 mark_inode_dirty(inode); 110 return ext2_add_nondir(dentry, inode); 111 } 112 113 static int ext2_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) 114 { 115 struct inode *inode = ext2_new_inode(dir, mode, NULL); 116 if (IS_ERR(inode)) 117 return PTR_ERR(inode); 118 119 ext2_set_file_ops(inode); 120 mark_inode_dirty(inode); 121 d_tmpfile(dentry, inode); 122 unlock_new_inode(inode); 123 return 0; 124 } 125 126 static int ext2_mknod (struct inode * dir, struct dentry *dentry, umode_t mode, dev_t rdev) 127 { 128 struct inode * inode; 129 int err; 130 131 err = dquot_initialize(dir); 132 if (err) 133 return err; 134 135 inode = ext2_new_inode (dir, mode, &dentry->d_name); 136 err = PTR_ERR(inode); 137 if (!IS_ERR(inode)) { 138 init_special_inode(inode, inode->i_mode, rdev); 139 #ifdef CONFIG_EXT2_FS_XATTR 140 inode->i_op = &ext2_special_inode_operations; 141 #endif 142 mark_inode_dirty(inode); 143 err = ext2_add_nondir(dentry, inode); 144 } 145 return err; 146 } 147 148 static int ext2_symlink (struct inode * dir, struct dentry * dentry, 149 const char * symname) 150 { 151 struct super_block * sb = dir->i_sb; 152 int err = -ENAMETOOLONG; 153 unsigned l = strlen(symname)+1; 154 struct inode * inode; 155 156 if (l > sb->s_blocksize) 157 goto out; 158 159 err = dquot_initialize(dir); 160 if (err) 161 goto out; 162 163 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name); 164 err = PTR_ERR(inode); 165 if (IS_ERR(inode)) 166 goto out; 167 168 if (l > sizeof (EXT2_I(inode)->i_data)) { 169 /* slow symlink */ 170 inode->i_op = &ext2_symlink_inode_operations; 171 inode_nohighmem(inode); 172 if (test_opt(inode->i_sb, NOBH)) 173 inode->i_mapping->a_ops = &ext2_nobh_aops; 174 else 175 inode->i_mapping->a_ops = &ext2_aops; 176 err = page_symlink(inode, symname, l); 177 if (err) 178 goto out_fail; 179 } else { 180 /* fast symlink */ 181 inode->i_op = &ext2_fast_symlink_inode_operations; 182 inode->i_link = (char*)EXT2_I(inode)->i_data; 183 memcpy(inode->i_link, symname, l); 184 inode->i_size = l-1; 185 } 186 mark_inode_dirty(inode); 187 188 err = ext2_add_nondir(dentry, inode); 189 out: 190 return err; 191 192 out_fail: 193 inode_dec_link_count(inode); 194 discard_new_inode(inode); 195 goto out; 196 } 197 198 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 199 struct dentry *dentry) 200 { 201 struct inode *inode = d_inode(old_dentry); 202 int err; 203 204 err = dquot_initialize(dir); 205 if (err) 206 return err; 207 208 inode->i_ctime = current_time(inode); 209 inode_inc_link_count(inode); 210 ihold(inode); 211 212 err = ext2_add_link(dentry, inode); 213 if (!err) { 214 d_instantiate(dentry, inode); 215 return 0; 216 } 217 inode_dec_link_count(inode); 218 iput(inode); 219 return err; 220 } 221 222 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode) 223 { 224 struct inode * inode; 225 int err; 226 227 err = dquot_initialize(dir); 228 if (err) 229 return err; 230 231 inode_inc_link_count(dir); 232 233 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 234 err = PTR_ERR(inode); 235 if (IS_ERR(inode)) 236 goto out_dir; 237 238 inode->i_op = &ext2_dir_inode_operations; 239 inode->i_fop = &ext2_dir_operations; 240 if (test_opt(inode->i_sb, NOBH)) 241 inode->i_mapping->a_ops = &ext2_nobh_aops; 242 else 243 inode->i_mapping->a_ops = &ext2_aops; 244 245 inode_inc_link_count(inode); 246 247 err = ext2_make_empty(inode, dir); 248 if (err) 249 goto out_fail; 250 251 err = ext2_add_link(dentry, inode); 252 if (err) 253 goto out_fail; 254 255 d_instantiate_new(dentry, inode); 256 out: 257 return err; 258 259 out_fail: 260 inode_dec_link_count(inode); 261 inode_dec_link_count(inode); 262 discard_new_inode(inode); 263 out_dir: 264 inode_dec_link_count(dir); 265 goto out; 266 } 267 268 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 269 { 270 struct inode * inode = d_inode(dentry); 271 struct ext2_dir_entry_2 * de; 272 struct page * page; 273 int err; 274 275 err = dquot_initialize(dir); 276 if (err) 277 goto out; 278 279 de = ext2_find_entry (dir, &dentry->d_name, &page); 280 if (!de) { 281 err = -ENOENT; 282 goto out; 283 } 284 285 err = ext2_delete_entry (de, page); 286 if (err) 287 goto out; 288 289 inode->i_ctime = dir->i_ctime; 290 inode_dec_link_count(inode); 291 err = 0; 292 out: 293 return err; 294 } 295 296 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 297 { 298 struct inode * inode = d_inode(dentry); 299 int err = -ENOTEMPTY; 300 301 if (ext2_empty_dir(inode)) { 302 err = ext2_unlink(dir, dentry); 303 if (!err) { 304 inode->i_size = 0; 305 inode_dec_link_count(inode); 306 inode_dec_link_count(dir); 307 } 308 } 309 return err; 310 } 311 312 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 313 struct inode * new_dir, struct dentry * new_dentry, 314 unsigned int flags) 315 { 316 struct inode * old_inode = d_inode(old_dentry); 317 struct inode * new_inode = d_inode(new_dentry); 318 struct page * dir_page = NULL; 319 struct ext2_dir_entry_2 * dir_de = NULL; 320 struct page * old_page; 321 struct ext2_dir_entry_2 * old_de; 322 int err; 323 324 if (flags & ~RENAME_NOREPLACE) 325 return -EINVAL; 326 327 err = dquot_initialize(old_dir); 328 if (err) 329 goto out; 330 331 err = dquot_initialize(new_dir); 332 if (err) 333 goto out; 334 335 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page); 336 if (!old_de) { 337 err = -ENOENT; 338 goto out; 339 } 340 341 if (S_ISDIR(old_inode->i_mode)) { 342 err = -EIO; 343 dir_de = ext2_dotdot(old_inode, &dir_page); 344 if (!dir_de) 345 goto out_old; 346 } 347 348 if (new_inode) { 349 struct page *new_page; 350 struct ext2_dir_entry_2 *new_de; 351 352 err = -ENOTEMPTY; 353 if (dir_de && !ext2_empty_dir (new_inode)) 354 goto out_dir; 355 356 err = -ENOENT; 357 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page); 358 if (!new_de) 359 goto out_dir; 360 ext2_set_link(new_dir, new_de, new_page, old_inode, 1); 361 new_inode->i_ctime = current_time(new_inode); 362 if (dir_de) 363 drop_nlink(new_inode); 364 inode_dec_link_count(new_inode); 365 } else { 366 err = ext2_add_link(new_dentry, old_inode); 367 if (err) 368 goto out_dir; 369 if (dir_de) 370 inode_inc_link_count(new_dir); 371 } 372 373 /* 374 * Like most other Unix systems, set the ctime for inodes on a 375 * rename. 376 */ 377 old_inode->i_ctime = current_time(old_inode); 378 mark_inode_dirty(old_inode); 379 380 ext2_delete_entry (old_de, old_page); 381 382 if (dir_de) { 383 if (old_dir != new_dir) 384 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0); 385 else { 386 kunmap(dir_page); 387 put_page(dir_page); 388 } 389 inode_dec_link_count(old_dir); 390 } 391 return 0; 392 393 394 out_dir: 395 if (dir_de) { 396 kunmap(dir_page); 397 put_page(dir_page); 398 } 399 out_old: 400 kunmap(old_page); 401 put_page(old_page); 402 out: 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 #ifdef CONFIG_EXT2_FS_XATTR 417 .listxattr = ext2_listxattr, 418 #endif 419 .setattr = ext2_setattr, 420 .get_acl = ext2_get_acl, 421 .set_acl = ext2_set_acl, 422 .tmpfile = ext2_tmpfile, 423 }; 424 425 const struct inode_operations ext2_special_inode_operations = { 426 #ifdef CONFIG_EXT2_FS_XATTR 427 .listxattr = ext2_listxattr, 428 #endif 429 .setattr = ext2_setattr, 430 .get_acl = ext2_get_acl, 431 .set_acl = ext2_set_acl, 432 }; 433