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 inode->i_op = &ext2_special_inode_operations; 140 mark_inode_dirty(inode); 141 err = ext2_add_nondir(dentry, inode); 142 } 143 return err; 144 } 145 146 static int ext2_symlink (struct inode * dir, struct dentry * dentry, 147 const char * symname) 148 { 149 struct super_block * sb = dir->i_sb; 150 int err = -ENAMETOOLONG; 151 unsigned l = strlen(symname)+1; 152 struct inode * inode; 153 154 if (l > sb->s_blocksize) 155 goto out; 156 157 err = dquot_initialize(dir); 158 if (err) 159 goto out; 160 161 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name); 162 err = PTR_ERR(inode); 163 if (IS_ERR(inode)) 164 goto out; 165 166 if (l > sizeof (EXT2_I(inode)->i_data)) { 167 /* slow symlink */ 168 inode->i_op = &ext2_symlink_inode_operations; 169 inode_nohighmem(inode); 170 if (test_opt(inode->i_sb, NOBH)) 171 inode->i_mapping->a_ops = &ext2_nobh_aops; 172 else 173 inode->i_mapping->a_ops = &ext2_aops; 174 err = page_symlink(inode, symname, l); 175 if (err) 176 goto out_fail; 177 } else { 178 /* fast symlink */ 179 inode->i_op = &ext2_fast_symlink_inode_operations; 180 inode->i_link = (char*)EXT2_I(inode)->i_data; 181 memcpy(inode->i_link, symname, l); 182 inode->i_size = l-1; 183 } 184 mark_inode_dirty(inode); 185 186 err = ext2_add_nondir(dentry, inode); 187 out: 188 return err; 189 190 out_fail: 191 inode_dec_link_count(inode); 192 discard_new_inode(inode); 193 goto out; 194 } 195 196 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 197 struct dentry *dentry) 198 { 199 struct inode *inode = d_inode(old_dentry); 200 int err; 201 202 err = dquot_initialize(dir); 203 if (err) 204 return err; 205 206 inode->i_ctime = current_time(inode); 207 inode_inc_link_count(inode); 208 ihold(inode); 209 210 err = ext2_add_link(dentry, inode); 211 if (!err) { 212 d_instantiate(dentry, inode); 213 return 0; 214 } 215 inode_dec_link_count(inode); 216 iput(inode); 217 return err; 218 } 219 220 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode) 221 { 222 struct inode * inode; 223 int err; 224 225 err = dquot_initialize(dir); 226 if (err) 227 return err; 228 229 inode_inc_link_count(dir); 230 231 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 232 err = PTR_ERR(inode); 233 if (IS_ERR(inode)) 234 goto out_dir; 235 236 inode->i_op = &ext2_dir_inode_operations; 237 inode->i_fop = &ext2_dir_operations; 238 if (test_opt(inode->i_sb, NOBH)) 239 inode->i_mapping->a_ops = &ext2_nobh_aops; 240 else 241 inode->i_mapping->a_ops = &ext2_aops; 242 243 inode_inc_link_count(inode); 244 245 err = ext2_make_empty(inode, dir); 246 if (err) 247 goto out_fail; 248 249 err = ext2_add_link(dentry, inode); 250 if (err) 251 goto out_fail; 252 253 d_instantiate_new(dentry, inode); 254 out: 255 return err; 256 257 out_fail: 258 inode_dec_link_count(inode); 259 inode_dec_link_count(inode); 260 discard_new_inode(inode); 261 out_dir: 262 inode_dec_link_count(dir); 263 goto out; 264 } 265 266 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 267 { 268 struct inode * inode = d_inode(dentry); 269 struct ext2_dir_entry_2 * de; 270 struct page * page; 271 int err; 272 273 err = dquot_initialize(dir); 274 if (err) 275 goto out; 276 277 de = ext2_find_entry (dir, &dentry->d_name, &page); 278 if (!de) { 279 err = -ENOENT; 280 goto out; 281 } 282 283 err = ext2_delete_entry (de, page); 284 if (err) 285 goto out; 286 287 inode->i_ctime = dir->i_ctime; 288 inode_dec_link_count(inode); 289 err = 0; 290 out: 291 return err; 292 } 293 294 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 295 { 296 struct inode * inode = d_inode(dentry); 297 int err = -ENOTEMPTY; 298 299 if (ext2_empty_dir(inode)) { 300 err = ext2_unlink(dir, dentry); 301 if (!err) { 302 inode->i_size = 0; 303 inode_dec_link_count(inode); 304 inode_dec_link_count(dir); 305 } 306 } 307 return err; 308 } 309 310 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 311 struct inode * new_dir, struct dentry * new_dentry, 312 unsigned int flags) 313 { 314 struct inode * old_inode = d_inode(old_dentry); 315 struct inode * new_inode = d_inode(new_dentry); 316 struct page * dir_page = NULL; 317 struct ext2_dir_entry_2 * dir_de = NULL; 318 struct page * old_page; 319 struct ext2_dir_entry_2 * old_de; 320 int err; 321 322 if (flags & ~RENAME_NOREPLACE) 323 return -EINVAL; 324 325 err = dquot_initialize(old_dir); 326 if (err) 327 goto out; 328 329 err = dquot_initialize(new_dir); 330 if (err) 331 goto out; 332 333 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page); 334 if (!old_de) { 335 err = -ENOENT; 336 goto out; 337 } 338 339 if (S_ISDIR(old_inode->i_mode)) { 340 err = -EIO; 341 dir_de = ext2_dotdot(old_inode, &dir_page); 342 if (!dir_de) 343 goto out_old; 344 } 345 346 if (new_inode) { 347 struct page *new_page; 348 struct ext2_dir_entry_2 *new_de; 349 350 err = -ENOTEMPTY; 351 if (dir_de && !ext2_empty_dir (new_inode)) 352 goto out_dir; 353 354 err = -ENOENT; 355 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page); 356 if (!new_de) 357 goto out_dir; 358 ext2_set_link(new_dir, new_de, new_page, old_inode, 1); 359 new_inode->i_ctime = current_time(new_inode); 360 if (dir_de) 361 drop_nlink(new_inode); 362 inode_dec_link_count(new_inode); 363 } else { 364 err = ext2_add_link(new_dentry, old_inode); 365 if (err) 366 goto out_dir; 367 if (dir_de) 368 inode_inc_link_count(new_dir); 369 } 370 371 /* 372 * Like most other Unix systems, set the ctime for inodes on a 373 * rename. 374 */ 375 old_inode->i_ctime = current_time(old_inode); 376 mark_inode_dirty(old_inode); 377 378 ext2_delete_entry (old_de, old_page); 379 380 if (dir_de) { 381 if (old_dir != new_dir) 382 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0); 383 else { 384 kunmap(dir_page); 385 put_page(dir_page); 386 } 387 inode_dec_link_count(old_dir); 388 } 389 return 0; 390 391 392 out_dir: 393 if (dir_de) { 394 kunmap(dir_page); 395 put_page(dir_page); 396 } 397 out_old: 398 kunmap(old_page); 399 put_page(old_page); 400 out: 401 return err; 402 } 403 404 const struct inode_operations ext2_dir_inode_operations = { 405 .create = ext2_create, 406 .lookup = ext2_lookup, 407 .link = ext2_link, 408 .unlink = ext2_unlink, 409 .symlink = ext2_symlink, 410 .mkdir = ext2_mkdir, 411 .rmdir = ext2_rmdir, 412 .mknod = ext2_mknod, 413 .rename = ext2_rename, 414 .listxattr = ext2_listxattr, 415 .getattr = ext2_getattr, 416 .setattr = ext2_setattr, 417 .get_acl = ext2_get_acl, 418 .set_acl = ext2_set_acl, 419 .tmpfile = ext2_tmpfile, 420 }; 421 422 const struct inode_operations ext2_special_inode_operations = { 423 .listxattr = ext2_listxattr, 424 .getattr = ext2_getattr, 425 .setattr = ext2_setattr, 426 .get_acl = ext2_get_acl, 427 .set_acl = ext2_set_acl, 428 }; 429