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 40static 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 56static 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 82struct 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 */ 103static int ext2_create (struct inode * dir, struct dentry * dentry, umode_t mode, bool excl) 104{ 105 struct inode *inode; 106 int err; 107 108 err = dquot_initialize(dir); 109 if (err) 110 return err; 111 112 inode = ext2_new_inode(dir, mode, &dentry->d_name); 113 if (IS_ERR(inode)) 114 return PTR_ERR(inode); 115 116 ext2_set_file_ops(inode); 117 mark_inode_dirty(inode); 118 return ext2_add_nondir(dentry, inode); 119} 120 121static int ext2_tmpfile(struct inode *dir, struct dentry *dentry, umode_t mode) 122{ 123 struct inode *inode = ext2_new_inode(dir, mode, NULL); 124 if (IS_ERR(inode)) 125 return PTR_ERR(inode); 126 127 ext2_set_file_ops(inode); 128 mark_inode_dirty(inode); 129 d_tmpfile(dentry, inode); 130 unlock_new_inode(inode); 131 return 0; 132} 133 134static int ext2_mknod (struct inode * dir, struct dentry *dentry, umode_t mode, dev_t rdev) 135{ 136 struct inode * inode; 137 int err; 138 139 err = dquot_initialize(dir); 140 if (err) 141 return err; 142 143 inode = ext2_new_inode (dir, mode, &dentry->d_name); 144 err = PTR_ERR(inode); 145 if (!IS_ERR(inode)) { 146 init_special_inode(inode, inode->i_mode, rdev); 147 inode->i_op = &ext2_special_inode_operations; 148 mark_inode_dirty(inode); 149 err = ext2_add_nondir(dentry, inode); 150 } 151 return err; 152} 153 154static int ext2_symlink (struct inode * dir, struct dentry * dentry, 155 const char * symname) 156{ 157 struct super_block * sb = dir->i_sb; 158 int err = -ENAMETOOLONG; 159 unsigned l = strlen(symname)+1; 160 struct inode * inode; 161 162 if (l > sb->s_blocksize) 163 goto out; 164 165 err = dquot_initialize(dir); 166 if (err) 167 goto out; 168 169 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO, &dentry->d_name); 170 err = PTR_ERR(inode); 171 if (IS_ERR(inode)) 172 goto out; 173 174 if (l > sizeof (EXT2_I(inode)->i_data)) { 175 /* slow symlink */ 176 inode->i_op = &ext2_symlink_inode_operations; 177 inode_nohighmem(inode); 178 if (test_opt(inode->i_sb, NOBH)) 179 inode->i_mapping->a_ops = &ext2_nobh_aops; 180 else 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); 195out: 196 return err; 197 198out_fail: 199 inode_dec_link_count(inode); 200 discard_new_inode(inode); 201 goto out; 202} 203 204static 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 228static int ext2_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode) 229{ 230 struct inode * inode; 231 int err; 232 233 err = dquot_initialize(dir); 234 if (err) 235 return err; 236 237 inode_inc_link_count(dir); 238 239 inode = ext2_new_inode(dir, S_IFDIR | mode, &dentry->d_name); 240 err = PTR_ERR(inode); 241 if (IS_ERR(inode)) 242 goto out_dir; 243 244 inode->i_op = &ext2_dir_inode_operations; 245 inode->i_fop = &ext2_dir_operations; 246 if (test_opt(inode->i_sb, NOBH)) 247 inode->i_mapping->a_ops = &ext2_nobh_aops; 248 else 249 inode->i_mapping->a_ops = &ext2_aops; 250 251 inode_inc_link_count(inode); 252 253 err = ext2_make_empty(inode, dir); 254 if (err) 255 goto out_fail; 256 257 err = ext2_add_link(dentry, inode); 258 if (err) 259 goto out_fail; 260 261 d_instantiate_new(dentry, inode); 262out: 263 return err; 264 265out_fail: 266 inode_dec_link_count(inode); 267 inode_dec_link_count(inode); 268 discard_new_inode(inode); 269out_dir: 270 inode_dec_link_count(dir); 271 goto out; 272} 273 274static int ext2_unlink(struct inode * dir, struct dentry *dentry) 275{ 276 struct inode * inode = d_inode(dentry); 277 struct ext2_dir_entry_2 * de; 278 struct page * page; 279 int err; 280 281 err = dquot_initialize(dir); 282 if (err) 283 goto out; 284 285 de = ext2_find_entry(dir, &dentry->d_name, &page); 286 if (IS_ERR(de)) { 287 err = PTR_ERR(de); 288 goto out; 289 } 290 291 err = ext2_delete_entry (de, page); 292 if (err) 293 goto out; 294 295 inode->i_ctime = dir->i_ctime; 296 inode_dec_link_count(inode); 297 err = 0; 298out: 299 return err; 300} 301 302static 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 318static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 319 struct inode * new_dir, struct dentry * new_dentry, 320 unsigned int flags) 321{ 322 struct inode * old_inode = d_inode(old_dentry); 323 struct inode * new_inode = d_inode(new_dentry); 324 struct page * dir_page = NULL; 325 struct ext2_dir_entry_2 * dir_de = NULL; 326 struct page * old_page; 327 struct ext2_dir_entry_2 * old_de; 328 int err; 329 330 if (flags & ~RENAME_NOREPLACE) 331 return -EINVAL; 332 333 err = dquot_initialize(old_dir); 334 if (err) 335 goto out; 336 337 err = dquot_initialize(new_dir); 338 if (err) 339 goto out; 340 341 old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_page); 342 if (IS_ERR(old_de)) { 343 err = PTR_ERR(old_de); 344 goto out; 345 } 346 347 if (S_ISDIR(old_inode->i_mode)) { 348 err = -EIO; 349 dir_de = ext2_dotdot(old_inode, &dir_page); 350 if (!dir_de) 351 goto out_old; 352 } 353 354 if (new_inode) { 355 struct page *new_page; 356 struct ext2_dir_entry_2 *new_de; 357 358 err = -ENOTEMPTY; 359 if (dir_de && !ext2_empty_dir (new_inode)) 360 goto out_dir; 361 362 new_de = ext2_find_entry(new_dir, &new_dentry->d_name, &new_page); 363 if (IS_ERR(new_de)) { 364 err = PTR_ERR(new_de); 365 goto out_dir; 366 } 367 ext2_set_link(new_dir, new_de, new_page, old_inode, 1); 368 new_inode->i_ctime = current_time(new_inode); 369 if (dir_de) 370 drop_nlink(new_inode); 371 inode_dec_link_count(new_inode); 372 } else { 373 err = ext2_add_link(new_dentry, old_inode); 374 if (err) 375 goto out_dir; 376 if (dir_de) 377 inode_inc_link_count(new_dir); 378 } 379 380 /* 381 * Like most other Unix systems, set the ctime for inodes on a 382 * rename. 383 */ 384 old_inode->i_ctime = current_time(old_inode); 385 mark_inode_dirty(old_inode); 386 387 ext2_delete_entry (old_de, old_page); 388 389 if (dir_de) { 390 if (old_dir != new_dir) 391 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0); 392 else { 393 kunmap(dir_page); 394 put_page(dir_page); 395 } 396 inode_dec_link_count(old_dir); 397 } 398 return 0; 399 400 401out_dir: 402 if (dir_de) { 403 kunmap(dir_page); 404 put_page(dir_page); 405 } 406out_old: 407 kunmap(old_page); 408 put_page(old_page); 409out: 410 return err; 411} 412 413const struct inode_operations ext2_dir_inode_operations = { 414 .create = ext2_create, 415 .lookup = ext2_lookup, 416 .link = ext2_link, 417 .unlink = ext2_unlink, 418 .symlink = ext2_symlink, 419 .mkdir = ext2_mkdir, 420 .rmdir = ext2_rmdir, 421 .mknod = ext2_mknod, 422 .rename = ext2_rename, 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 .tmpfile = ext2_tmpfile, 429}; 430 431const struct inode_operations ext2_special_inode_operations = { 432 .listxattr = ext2_listxattr, 433 .getattr = ext2_getattr, 434 .setattr = ext2_setattr, 435 .get_acl = ext2_get_acl, 436 .set_acl = ext2_set_acl, 437}; 438