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 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 */ 102static int ext2_create (struct mnt_idmap * idmap, 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 122static int ext2_tmpfile(struct mnt_idmap *idmap, struct inode *dir, 123 struct file *file, 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(file, inode); 132 unlock_new_inode(inode); 133 return finish_open_simple(file, 0); 134} 135 136static int ext2_mknod (struct mnt_idmap * idmap, 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 157static int ext2_symlink (struct mnt_idmap * idmap, 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); 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_set_ctime_current(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 mnt_idmap * idmap, 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); 260out: 261 return err; 262 263out_fail: 264 inode_dec_link_count(inode); 265 inode_dec_link_count(inode); 266 discard_new_inode(inode); 267out_dir: 268 inode_dec_link_count(dir); 269 goto out; 270} 271 272static 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 int err; 278 279 err = dquot_initialize(dir); 280 if (err) 281 goto out; 282 283 de = ext2_find_entry(dir, &dentry->d_name, &page); 284 if (IS_ERR(de)) { 285 err = PTR_ERR(de); 286 goto out; 287 } 288 289 err = ext2_delete_entry(de, page); 290 ext2_put_page(page, de); 291 if (err) 292 goto out; 293 294 inode_set_ctime_to_ts(inode, inode_get_ctime(dir)); 295 inode_dec_link_count(inode); 296 err = 0; 297out: 298 return err; 299} 300 301static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 302{ 303 struct inode * inode = d_inode(dentry); 304 int err = -ENOTEMPTY; 305 306 if (ext2_empty_dir(inode)) { 307 err = ext2_unlink(dir, dentry); 308 if (!err) { 309 inode->i_size = 0; 310 inode_dec_link_count(inode); 311 inode_dec_link_count(dir); 312 } 313 } 314 return err; 315} 316 317static int ext2_rename (struct mnt_idmap * idmap, 318 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 return err; 336 337 err = dquot_initialize(new_dir); 338 if (err) 339 return err; 340 341 old_de = ext2_find_entry(old_dir, &old_dentry->d_name, &old_page); 342 if (IS_ERR(old_de)) 343 return PTR_ERR(old_de); 344 345 if (S_ISDIR(old_inode->i_mode)) { 346 err = -EIO; 347 dir_de = ext2_dotdot(old_inode, &dir_page); 348 if (!dir_de) 349 goto out_old; 350 } 351 352 if (new_inode) { 353 struct page *new_page; 354 struct ext2_dir_entry_2 *new_de; 355 356 err = -ENOTEMPTY; 357 if (dir_de && !ext2_empty_dir (new_inode)) 358 goto out_dir; 359 360 new_de = ext2_find_entry(new_dir, &new_dentry->d_name, 361 &new_page); 362 if (IS_ERR(new_de)) { 363 err = PTR_ERR(new_de); 364 goto out_dir; 365 } 366 err = ext2_set_link(new_dir, new_de, new_page, old_inode, true); 367 ext2_put_page(new_page, new_de); 368 if (err) 369 goto out_dir; 370 inode_set_ctime_current(new_inode); 371 if (dir_de) 372 drop_nlink(new_inode); 373 inode_dec_link_count(new_inode); 374 } else { 375 err = ext2_add_link(new_dentry, old_inode); 376 if (err) 377 goto out_dir; 378 if (dir_de) 379 inode_inc_link_count(new_dir); 380 } 381 382 /* 383 * Like most other Unix systems, set the ctime for inodes on a 384 * rename. 385 */ 386 inode_set_ctime_current(old_inode); 387 mark_inode_dirty(old_inode); 388 389 err = ext2_delete_entry(old_de, old_page); 390 if (!err && dir_de) { 391 if (old_dir != new_dir) 392 err = ext2_set_link(old_inode, dir_de, dir_page, 393 new_dir, false); 394 395 inode_dec_link_count(old_dir); 396 } 397out_dir: 398 if (dir_de) 399 ext2_put_page(dir_page, dir_de); 400out_old: 401 ext2_put_page(old_page, old_de); 402 return err; 403} 404 405const struct inode_operations ext2_dir_inode_operations = { 406 .create = ext2_create, 407 .lookup = ext2_lookup, 408 .link = ext2_link, 409 .unlink = ext2_unlink, 410 .symlink = ext2_symlink, 411 .mkdir = ext2_mkdir, 412 .rmdir = ext2_rmdir, 413 .mknod = ext2_mknod, 414 .rename = ext2_rename, 415 .listxattr = ext2_listxattr, 416 .getattr = ext2_getattr, 417 .setattr = ext2_setattr, 418 .get_inode_acl = ext2_get_acl, 419 .set_acl = ext2_set_acl, 420 .tmpfile = ext2_tmpfile, 421 .fileattr_get = ext2_fileattr_get, 422 .fileattr_set = ext2_fileattr_set, 423}; 424 425const struct inode_operations ext2_special_inode_operations = { 426 .listxattr = ext2_listxattr, 427 .getattr = ext2_getattr, 428 .setattr = ext2_setattr, 429 .get_inode_acl = ext2_get_acl, 430 .set_acl = ext2_set_acl, 431}; 432