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 /* 40 * Couple of helper functions - make the code slightly cleaner. 41 */ 42 43 static inline void ext2_inc_count(struct inode *inode) 44 { 45 inode->i_nlink++; 46 mark_inode_dirty(inode); 47 } 48 49 static inline void ext2_dec_count(struct inode *inode) 50 { 51 inode->i_nlink--; 52 mark_inode_dirty(inode); 53 } 54 55 static inline int ext2_add_nondir(struct dentry *dentry, struct inode *inode) 56 { 57 int err = ext2_add_link(dentry, inode); 58 if (!err) { 59 d_instantiate(dentry, inode); 60 return 0; 61 } 62 ext2_dec_count(inode); 63 iput(inode); 64 return err; 65 } 66 67 /* 68 * Methods themselves. 69 */ 70 71 static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd) 72 { 73 struct inode * inode; 74 ino_t ino; 75 76 if (dentry->d_name.len > EXT2_NAME_LEN) 77 return ERR_PTR(-ENAMETOOLONG); 78 79 ino = ext2_inode_by_name(dir, dentry); 80 inode = NULL; 81 if (ino) { 82 inode = iget(dir->i_sb, ino); 83 if (!inode) 84 return ERR_PTR(-EACCES); 85 } 86 if (inode) 87 return d_splice_alias(inode, dentry); 88 d_add(dentry, inode); 89 return NULL; 90 } 91 92 struct dentry *ext2_get_parent(struct dentry *child) 93 { 94 unsigned long ino; 95 struct dentry *parent; 96 struct inode *inode; 97 struct dentry dotdot; 98 99 dotdot.d_name.name = ".."; 100 dotdot.d_name.len = 2; 101 102 ino = ext2_inode_by_name(child->d_inode, &dotdot); 103 if (!ino) 104 return ERR_PTR(-ENOENT); 105 inode = iget(child->d_inode->i_sb, ino); 106 107 if (!inode) 108 return ERR_PTR(-EACCES); 109 parent = d_alloc_anon(inode); 110 if (!parent) { 111 iput(inode); 112 parent = ERR_PTR(-ENOMEM); 113 } 114 return parent; 115 } 116 117 /* 118 * By the time this is called, we already have created 119 * the directory cache entry for the new file, but it 120 * is so far negative - it has no inode. 121 * 122 * If the create succeeds, we fill in the inode information 123 * with d_instantiate(). 124 */ 125 static int ext2_create (struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd) 126 { 127 struct inode * inode = ext2_new_inode (dir, mode); 128 int err = PTR_ERR(inode); 129 if (!IS_ERR(inode)) { 130 inode->i_op = &ext2_file_inode_operations; 131 if (ext2_use_xip(inode->i_sb)) { 132 inode->i_mapping->a_ops = &ext2_aops_xip; 133 inode->i_fop = &ext2_xip_file_operations; 134 } else if (test_opt(inode->i_sb, NOBH)) { 135 inode->i_mapping->a_ops = &ext2_nobh_aops; 136 inode->i_fop = &ext2_file_operations; 137 } else { 138 inode->i_mapping->a_ops = &ext2_aops; 139 inode->i_fop = &ext2_file_operations; 140 } 141 mark_inode_dirty(inode); 142 err = ext2_add_nondir(dentry, inode); 143 } 144 return err; 145 } 146 147 static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev) 148 { 149 struct inode * inode; 150 int err; 151 152 if (!new_valid_dev(rdev)) 153 return -EINVAL; 154 155 inode = ext2_new_inode (dir, mode); 156 err = PTR_ERR(inode); 157 if (!IS_ERR(inode)) { 158 init_special_inode(inode, inode->i_mode, rdev); 159 #ifdef CONFIG_EXT2_FS_XATTR 160 inode->i_op = &ext2_special_inode_operations; 161 #endif 162 mark_inode_dirty(inode); 163 err = ext2_add_nondir(dentry, inode); 164 } 165 return err; 166 } 167 168 static int ext2_symlink (struct inode * dir, struct dentry * dentry, 169 const char * symname) 170 { 171 struct super_block * sb = dir->i_sb; 172 int err = -ENAMETOOLONG; 173 unsigned l = strlen(symname)+1; 174 struct inode * inode; 175 176 if (l > sb->s_blocksize) 177 goto out; 178 179 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO); 180 err = PTR_ERR(inode); 181 if (IS_ERR(inode)) 182 goto out; 183 184 if (l > sizeof (EXT2_I(inode)->i_data)) { 185 /* slow symlink */ 186 inode->i_op = &ext2_symlink_inode_operations; 187 if (test_opt(inode->i_sb, NOBH)) 188 inode->i_mapping->a_ops = &ext2_nobh_aops; 189 else 190 inode->i_mapping->a_ops = &ext2_aops; 191 err = page_symlink(inode, symname, l); 192 if (err) 193 goto out_fail; 194 } else { 195 /* fast symlink */ 196 inode->i_op = &ext2_fast_symlink_inode_operations; 197 memcpy((char*)(EXT2_I(inode)->i_data),symname,l); 198 inode->i_size = l-1; 199 } 200 mark_inode_dirty(inode); 201 202 err = ext2_add_nondir(dentry, inode); 203 out: 204 return err; 205 206 out_fail: 207 ext2_dec_count(inode); 208 iput (inode); 209 goto out; 210 } 211 212 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 213 struct dentry *dentry) 214 { 215 struct inode *inode = old_dentry->d_inode; 216 217 if (inode->i_nlink >= EXT2_LINK_MAX) 218 return -EMLINK; 219 220 inode->i_ctime = CURRENT_TIME_SEC; 221 ext2_inc_count(inode); 222 atomic_inc(&inode->i_count); 223 224 return ext2_add_nondir(dentry, inode); 225 } 226 227 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode) 228 { 229 struct inode * inode; 230 int err = -EMLINK; 231 232 if (dir->i_nlink >= EXT2_LINK_MAX) 233 goto out; 234 235 ext2_inc_count(dir); 236 237 inode = ext2_new_inode (dir, S_IFDIR | mode); 238 err = PTR_ERR(inode); 239 if (IS_ERR(inode)) 240 goto out_dir; 241 242 inode->i_op = &ext2_dir_inode_operations; 243 inode->i_fop = &ext2_dir_operations; 244 if (test_opt(inode->i_sb, NOBH)) 245 inode->i_mapping->a_ops = &ext2_nobh_aops; 246 else 247 inode->i_mapping->a_ops = &ext2_aops; 248 249 ext2_inc_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(dentry, inode); 260 out: 261 return err; 262 263 out_fail: 264 ext2_dec_count(inode); 265 ext2_dec_count(inode); 266 iput(inode); 267 out_dir: 268 ext2_dec_count(dir); 269 goto out; 270 } 271 272 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 273 { 274 struct inode * inode = dentry->d_inode; 275 struct ext2_dir_entry_2 * de; 276 struct page * page; 277 int err = -ENOENT; 278 279 de = ext2_find_entry (dir, dentry, &page); 280 if (!de) 281 goto out; 282 283 err = ext2_delete_entry (de, page); 284 if (err) 285 goto out; 286 287 inode->i_ctime = dir->i_ctime; 288 ext2_dec_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 = dentry->d_inode; 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 ext2_dec_count(inode); 304 ext2_dec_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 { 313 struct inode * old_inode = old_dentry->d_inode; 314 struct inode * new_inode = new_dentry->d_inode; 315 struct page * dir_page = NULL; 316 struct ext2_dir_entry_2 * dir_de = NULL; 317 struct page * old_page; 318 struct ext2_dir_entry_2 * old_de; 319 int err = -ENOENT; 320 321 old_de = ext2_find_entry (old_dir, old_dentry, &old_page); 322 if (!old_de) 323 goto out; 324 325 if (S_ISDIR(old_inode->i_mode)) { 326 err = -EIO; 327 dir_de = ext2_dotdot(old_inode, &dir_page); 328 if (!dir_de) 329 goto out_old; 330 } 331 332 if (new_inode) { 333 struct page *new_page; 334 struct ext2_dir_entry_2 *new_de; 335 336 err = -ENOTEMPTY; 337 if (dir_de && !ext2_empty_dir (new_inode)) 338 goto out_dir; 339 340 err = -ENOENT; 341 new_de = ext2_find_entry (new_dir, new_dentry, &new_page); 342 if (!new_de) 343 goto out_dir; 344 ext2_inc_count(old_inode); 345 ext2_set_link(new_dir, new_de, new_page, old_inode); 346 new_inode->i_ctime = CURRENT_TIME_SEC; 347 if (dir_de) 348 new_inode->i_nlink--; 349 ext2_dec_count(new_inode); 350 } else { 351 if (dir_de) { 352 err = -EMLINK; 353 if (new_dir->i_nlink >= EXT2_LINK_MAX) 354 goto out_dir; 355 } 356 ext2_inc_count(old_inode); 357 err = ext2_add_link(new_dentry, old_inode); 358 if (err) { 359 ext2_dec_count(old_inode); 360 goto out_dir; 361 } 362 if (dir_de) 363 ext2_inc_count(new_dir); 364 } 365 366 /* 367 * Like most other Unix systems, set the ctime for inodes on a 368 * rename. 369 * ext2_dec_count() will mark the inode dirty. 370 */ 371 old_inode->i_ctime = CURRENT_TIME_SEC; 372 373 ext2_delete_entry (old_de, old_page); 374 ext2_dec_count(old_inode); 375 376 if (dir_de) { 377 ext2_set_link(old_inode, dir_de, dir_page, new_dir); 378 ext2_dec_count(old_dir); 379 } 380 return 0; 381 382 383 out_dir: 384 if (dir_de) { 385 kunmap(dir_page); 386 page_cache_release(dir_page); 387 } 388 out_old: 389 kunmap(old_page); 390 page_cache_release(old_page); 391 out: 392 return err; 393 } 394 395 struct inode_operations ext2_dir_inode_operations = { 396 .create = ext2_create, 397 .lookup = ext2_lookup, 398 .link = ext2_link, 399 .unlink = ext2_unlink, 400 .symlink = ext2_symlink, 401 .mkdir = ext2_mkdir, 402 .rmdir = ext2_rmdir, 403 .mknod = ext2_mknod, 404 .rename = ext2_rename, 405 #ifdef CONFIG_EXT2_FS_XATTR 406 .setxattr = generic_setxattr, 407 .getxattr = generic_getxattr, 408 .listxattr = ext2_listxattr, 409 .removexattr = generic_removexattr, 410 #endif 411 .setattr = ext2_setattr, 412 .permission = ext2_permission, 413 }; 414 415 struct inode_operations ext2_special_inode_operations = { 416 #ifdef CONFIG_EXT2_FS_XATTR 417 .setxattr = generic_setxattr, 418 .getxattr = generic_getxattr, 419 .listxattr = ext2_listxattr, 420 .removexattr = generic_removexattr, 421 #endif 422 .setattr = ext2_setattr, 423 .permission = ext2_permission, 424 }; 425