1 /* 2 * linux/fs/ext2/namei.c 3 * 4 * Rewrite to pagecache. Almost all code had been changed, so blame me 5 * if the things go wrong. Please, send bug reports to 6 * viro@parcelfarce.linux.theplanet.co.uk 7 * 8 * Stuff here is basically a glue between the VFS and generic UNIXish 9 * filesystem that keeps everything in pagecache. All knowledge of the 10 * directory layout is in fs/ext2/dir.c - it turned out to be easily separatable 11 * and it's easier to debug that way. In principle we might want to 12 * generalize that a bit and turn it into a library. Or not. 13 * 14 * The only non-static object here is ext2_dir_inode_operations. 15 * 16 * TODO: get rid of kmap() use, add readahead. 17 * 18 * Copyright (C) 1992, 1993, 1994, 1995 19 * Remy Card (card@masi.ibp.fr) 20 * Laboratoire MASI - Institut Blaise Pascal 21 * Universite Pierre et Marie Curie (Paris VI) 22 * 23 * from 24 * 25 * linux/fs/minix/namei.c 26 * 27 * Copyright (C) 1991, 1992 Linus Torvalds 28 * 29 * Big-endian to little-endian byte-swapping/bitmaps by 30 * David S. Miller (davem@caip.rutgers.edu), 1995 31 */ 32 33 #include <linux/pagemap.h> 34 #include "ext2.h" 35 #include "xattr.h" 36 #include "acl.h" 37 #include "xip.h" 38 39 static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode) 40 { 41 int err = ext2_add_link(dentry, inode); 42 if (!err) { 43 d_instantiate(dentry, inode); 44 unlock_new_inode(inode); 45 return 0; 46 } 47 inode_dec_link_count(inode); 48 unlock_new_inode(inode); 49 iput(inode); 50 return err; 51 } 52 53 /* 54 * Methods themselves. 55 */ 56 57 static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd) 58 { 59 struct inode * inode; 60 ino_t ino; 61 62 if (dentry->d_name.len > EXT2_NAME_LEN) 63 return ERR_PTR(-ENAMETOOLONG); 64 65 ino = ext2_inode_by_name(dir, &dentry->d_name); 66 inode = NULL; 67 if (ino) { 68 inode = ext2_iget(dir->i_sb, ino); 69 if (unlikely(IS_ERR(inode))) { 70 if (PTR_ERR(inode) == -ESTALE) { 71 ext2_error(dir->i_sb, __func__, 72 "deleted inode referenced: %lu", 73 (unsigned long) ino); 74 return ERR_PTR(-EIO); 75 } else { 76 return ERR_CAST(inode); 77 } 78 } 79 } 80 return d_splice_alias(inode, dentry); 81 } 82 83 struct dentry *ext2_get_parent(struct dentry *child) 84 { 85 struct qstr dotdot = {.name = "..", .len = 2}; 86 unsigned long ino = ext2_inode_by_name(child->d_inode, &dotdot); 87 if (!ino) 88 return ERR_PTR(-ENOENT); 89 return d_obtain_alias(ext2_iget(child->d_inode->i_sb, ino)); 90 } 91 92 /* 93 * By the time this is called, we already have created 94 * the directory cache entry for the new file, but it 95 * is so far negative - it has no inode. 96 * 97 * If the create succeeds, we fill in the inode information 98 * with d_instantiate(). 99 */ 100 static int ext2_create (struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd) 101 { 102 struct inode * inode = ext2_new_inode (dir, mode); 103 int err = PTR_ERR(inode); 104 if (!IS_ERR(inode)) { 105 inode->i_op = &ext2_file_inode_operations; 106 if (ext2_use_xip(inode->i_sb)) { 107 inode->i_mapping->a_ops = &ext2_aops_xip; 108 inode->i_fop = &ext2_xip_file_operations; 109 } else if (test_opt(inode->i_sb, NOBH)) { 110 inode->i_mapping->a_ops = &ext2_nobh_aops; 111 inode->i_fop = &ext2_file_operations; 112 } else { 113 inode->i_mapping->a_ops = &ext2_aops; 114 inode->i_fop = &ext2_file_operations; 115 } 116 mark_inode_dirty(inode); 117 err = ext2_add_nondir(dentry, inode); 118 } 119 return err; 120 } 121 122 static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev) 123 { 124 struct inode * inode; 125 int err; 126 127 if (!new_valid_dev(rdev)) 128 return -EINVAL; 129 130 inode = ext2_new_inode (dir, mode); 131 err = PTR_ERR(inode); 132 if (!IS_ERR(inode)) { 133 init_special_inode(inode, inode->i_mode, rdev); 134 #ifdef CONFIG_EXT2_FS_XATTR 135 inode->i_op = &ext2_special_inode_operations; 136 #endif 137 mark_inode_dirty(inode); 138 err = ext2_add_nondir(dentry, inode); 139 } 140 return err; 141 } 142 143 static int ext2_symlink (struct inode * dir, struct dentry * dentry, 144 const char * symname) 145 { 146 struct super_block * sb = dir->i_sb; 147 int err = -ENAMETOOLONG; 148 unsigned l = strlen(symname)+1; 149 struct inode * inode; 150 151 if (l > sb->s_blocksize) 152 goto out; 153 154 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO); 155 err = PTR_ERR(inode); 156 if (IS_ERR(inode)) 157 goto out; 158 159 if (l > sizeof (EXT2_I(inode)->i_data)) { 160 /* slow symlink */ 161 inode->i_op = &ext2_symlink_inode_operations; 162 if (test_opt(inode->i_sb, NOBH)) 163 inode->i_mapping->a_ops = &ext2_nobh_aops; 164 else 165 inode->i_mapping->a_ops = &ext2_aops; 166 err = page_symlink(inode, symname, l); 167 if (err) 168 goto out_fail; 169 } else { 170 /* fast symlink */ 171 inode->i_op = &ext2_fast_symlink_inode_operations; 172 memcpy((char*)(EXT2_I(inode)->i_data),symname,l); 173 inode->i_size = l-1; 174 } 175 mark_inode_dirty(inode); 176 177 err = ext2_add_nondir(dentry, inode); 178 out: 179 return err; 180 181 out_fail: 182 inode_dec_link_count(inode); 183 unlock_new_inode(inode); 184 iput (inode); 185 goto out; 186 } 187 188 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 189 struct dentry *dentry) 190 { 191 struct inode *inode = old_dentry->d_inode; 192 int err; 193 194 if (inode->i_nlink >= EXT2_LINK_MAX) 195 return -EMLINK; 196 197 inode->i_ctime = CURRENT_TIME_SEC; 198 inode_inc_link_count(inode); 199 atomic_inc(&inode->i_count); 200 201 err = ext2_add_link(dentry, inode); 202 if (!err) { 203 d_instantiate(dentry, inode); 204 return 0; 205 } 206 inode_dec_link_count(inode); 207 iput(inode); 208 return err; 209 } 210 211 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode) 212 { 213 struct inode * inode; 214 int err = -EMLINK; 215 216 if (dir->i_nlink >= EXT2_LINK_MAX) 217 goto out; 218 219 inode_inc_link_count(dir); 220 221 inode = ext2_new_inode (dir, S_IFDIR | mode); 222 err = PTR_ERR(inode); 223 if (IS_ERR(inode)) 224 goto out_dir; 225 226 inode->i_op = &ext2_dir_inode_operations; 227 inode->i_fop = &ext2_dir_operations; 228 if (test_opt(inode->i_sb, NOBH)) 229 inode->i_mapping->a_ops = &ext2_nobh_aops; 230 else 231 inode->i_mapping->a_ops = &ext2_aops; 232 233 inode_inc_link_count(inode); 234 235 err = ext2_make_empty(inode, dir); 236 if (err) 237 goto out_fail; 238 239 err = ext2_add_link(dentry, inode); 240 if (err) 241 goto out_fail; 242 243 d_instantiate(dentry, inode); 244 unlock_new_inode(inode); 245 out: 246 return err; 247 248 out_fail: 249 inode_dec_link_count(inode); 250 inode_dec_link_count(inode); 251 unlock_new_inode(inode); 252 iput(inode); 253 out_dir: 254 inode_dec_link_count(dir); 255 goto out; 256 } 257 258 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 259 { 260 struct inode * inode = dentry->d_inode; 261 struct ext2_dir_entry_2 * de; 262 struct page * page; 263 int err = -ENOENT; 264 265 de = ext2_find_entry (dir, &dentry->d_name, &page); 266 if (!de) 267 goto out; 268 269 err = ext2_delete_entry (de, page); 270 if (err) 271 goto out; 272 273 inode->i_ctime = dir->i_ctime; 274 inode_dec_link_count(inode); 275 err = 0; 276 out: 277 return err; 278 } 279 280 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 281 { 282 struct inode * inode = dentry->d_inode; 283 int err = -ENOTEMPTY; 284 285 if (ext2_empty_dir(inode)) { 286 err = ext2_unlink(dir, dentry); 287 if (!err) { 288 inode->i_size = 0; 289 inode_dec_link_count(inode); 290 inode_dec_link_count(dir); 291 } 292 } 293 return err; 294 } 295 296 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 297 struct inode * new_dir, struct dentry * new_dentry ) 298 { 299 struct inode * old_inode = old_dentry->d_inode; 300 struct inode * new_inode = new_dentry->d_inode; 301 struct page * dir_page = NULL; 302 struct ext2_dir_entry_2 * dir_de = NULL; 303 struct page * old_page; 304 struct ext2_dir_entry_2 * old_de; 305 int err = -ENOENT; 306 307 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page); 308 if (!old_de) 309 goto out; 310 311 if (S_ISDIR(old_inode->i_mode)) { 312 err = -EIO; 313 dir_de = ext2_dotdot(old_inode, &dir_page); 314 if (!dir_de) 315 goto out_old; 316 } 317 318 if (new_inode) { 319 struct page *new_page; 320 struct ext2_dir_entry_2 *new_de; 321 322 err = -ENOTEMPTY; 323 if (dir_de && !ext2_empty_dir (new_inode)) 324 goto out_dir; 325 326 err = -ENOENT; 327 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page); 328 if (!new_de) 329 goto out_dir; 330 inode_inc_link_count(old_inode); 331 ext2_set_link(new_dir, new_de, new_page, old_inode, 1); 332 new_inode->i_ctime = CURRENT_TIME_SEC; 333 if (dir_de) 334 drop_nlink(new_inode); 335 inode_dec_link_count(new_inode); 336 } else { 337 if (dir_de) { 338 err = -EMLINK; 339 if (new_dir->i_nlink >= EXT2_LINK_MAX) 340 goto out_dir; 341 } 342 inode_inc_link_count(old_inode); 343 err = ext2_add_link(new_dentry, old_inode); 344 if (err) { 345 inode_dec_link_count(old_inode); 346 goto out_dir; 347 } 348 if (dir_de) 349 inode_inc_link_count(new_dir); 350 } 351 352 /* 353 * Like most other Unix systems, set the ctime for inodes on a 354 * rename. 355 * inode_dec_link_count() will mark the inode dirty. 356 */ 357 old_inode->i_ctime = CURRENT_TIME_SEC; 358 359 ext2_delete_entry (old_de, old_page); 360 inode_dec_link_count(old_inode); 361 362 if (dir_de) { 363 if (old_dir != new_dir) 364 ext2_set_link(old_inode, dir_de, dir_page, new_dir, 0); 365 else { 366 kunmap(dir_page); 367 page_cache_release(dir_page); 368 } 369 inode_dec_link_count(old_dir); 370 } 371 return 0; 372 373 374 out_dir: 375 if (dir_de) { 376 kunmap(dir_page); 377 page_cache_release(dir_page); 378 } 379 out_old: 380 kunmap(old_page); 381 page_cache_release(old_page); 382 out: 383 return err; 384 } 385 386 const struct inode_operations ext2_dir_inode_operations = { 387 .create = ext2_create, 388 .lookup = ext2_lookup, 389 .link = ext2_link, 390 .unlink = ext2_unlink, 391 .symlink = ext2_symlink, 392 .mkdir = ext2_mkdir, 393 .rmdir = ext2_rmdir, 394 .mknod = ext2_mknod, 395 .rename = ext2_rename, 396 #ifdef CONFIG_EXT2_FS_XATTR 397 .setxattr = generic_setxattr, 398 .getxattr = generic_getxattr, 399 .listxattr = ext2_listxattr, 400 .removexattr = generic_removexattr, 401 #endif 402 .setattr = ext2_setattr, 403 .check_acl = ext2_check_acl, 404 }; 405 406 const struct inode_operations ext2_special_inode_operations = { 407 #ifdef CONFIG_EXT2_FS_XATTR 408 .setxattr = generic_setxattr, 409 .getxattr = generic_getxattr, 410 .listxattr = ext2_listxattr, 411 .removexattr = generic_removexattr, 412 #endif 413 .setattr = ext2_setattr, 414 .check_acl = ext2_check_acl, 415 }; 416