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 (IS_ERR(inode)) 70 return ERR_CAST(inode); 71 } 72 return d_splice_alias(inode, dentry); 73 } 74 75 struct dentry *ext2_get_parent(struct dentry *child) 76 { 77 struct qstr dotdot = {.name = "..", .len = 2}; 78 unsigned long ino = ext2_inode_by_name(child->d_inode, &dotdot); 79 if (!ino) 80 return ERR_PTR(-ENOENT); 81 return d_obtain_alias(ext2_iget(child->d_inode->i_sb, ino)); 82 } 83 84 /* 85 * By the time this is called, we already have created 86 * the directory cache entry for the new file, but it 87 * is so far negative - it has no inode. 88 * 89 * If the create succeeds, we fill in the inode information 90 * with d_instantiate(). 91 */ 92 static int ext2_create (struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd) 93 { 94 struct inode * inode = ext2_new_inode (dir, mode); 95 int err = PTR_ERR(inode); 96 if (!IS_ERR(inode)) { 97 inode->i_op = &ext2_file_inode_operations; 98 if (ext2_use_xip(inode->i_sb)) { 99 inode->i_mapping->a_ops = &ext2_aops_xip; 100 inode->i_fop = &ext2_xip_file_operations; 101 } else if (test_opt(inode->i_sb, NOBH)) { 102 inode->i_mapping->a_ops = &ext2_nobh_aops; 103 inode->i_fop = &ext2_file_operations; 104 } else { 105 inode->i_mapping->a_ops = &ext2_aops; 106 inode->i_fop = &ext2_file_operations; 107 } 108 mark_inode_dirty(inode); 109 err = ext2_add_nondir(dentry, inode); 110 } 111 return err; 112 } 113 114 static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev) 115 { 116 struct inode * inode; 117 int err; 118 119 if (!new_valid_dev(rdev)) 120 return -EINVAL; 121 122 inode = ext2_new_inode (dir, mode); 123 err = PTR_ERR(inode); 124 if (!IS_ERR(inode)) { 125 init_special_inode(inode, inode->i_mode, rdev); 126 #ifdef CONFIG_EXT2_FS_XATTR 127 inode->i_op = &ext2_special_inode_operations; 128 #endif 129 mark_inode_dirty(inode); 130 err = ext2_add_nondir(dentry, inode); 131 } 132 return err; 133 } 134 135 static int ext2_symlink (struct inode * dir, struct dentry * dentry, 136 const char * symname) 137 { 138 struct super_block * sb = dir->i_sb; 139 int err = -ENAMETOOLONG; 140 unsigned l = strlen(symname)+1; 141 struct inode * inode; 142 143 if (l > sb->s_blocksize) 144 goto out; 145 146 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO); 147 err = PTR_ERR(inode); 148 if (IS_ERR(inode)) 149 goto out; 150 151 if (l > sizeof (EXT2_I(inode)->i_data)) { 152 /* slow symlink */ 153 inode->i_op = &ext2_symlink_inode_operations; 154 if (test_opt(inode->i_sb, NOBH)) 155 inode->i_mapping->a_ops = &ext2_nobh_aops; 156 else 157 inode->i_mapping->a_ops = &ext2_aops; 158 err = page_symlink(inode, symname, l); 159 if (err) 160 goto out_fail; 161 } else { 162 /* fast symlink */ 163 inode->i_op = &ext2_fast_symlink_inode_operations; 164 memcpy((char*)(EXT2_I(inode)->i_data),symname,l); 165 inode->i_size = l-1; 166 } 167 mark_inode_dirty(inode); 168 169 err = ext2_add_nondir(dentry, inode); 170 out: 171 return err; 172 173 out_fail: 174 inode_dec_link_count(inode); 175 unlock_new_inode(inode); 176 iput (inode); 177 goto out; 178 } 179 180 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 181 struct dentry *dentry) 182 { 183 struct inode *inode = old_dentry->d_inode; 184 int err; 185 186 if (inode->i_nlink >= EXT2_LINK_MAX) 187 return -EMLINK; 188 189 inode->i_ctime = CURRENT_TIME_SEC; 190 inode_inc_link_count(inode); 191 atomic_inc(&inode->i_count); 192 193 err = ext2_add_link(dentry, inode); 194 if (!err) { 195 d_instantiate(dentry, inode); 196 return 0; 197 } 198 inode_dec_link_count(inode); 199 iput(inode); 200 return err; 201 } 202 203 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode) 204 { 205 struct inode * inode; 206 int err = -EMLINK; 207 208 if (dir->i_nlink >= EXT2_LINK_MAX) 209 goto out; 210 211 inode_inc_link_count(dir); 212 213 inode = ext2_new_inode (dir, S_IFDIR | mode); 214 err = PTR_ERR(inode); 215 if (IS_ERR(inode)) 216 goto out_dir; 217 218 inode->i_op = &ext2_dir_inode_operations; 219 inode->i_fop = &ext2_dir_operations; 220 if (test_opt(inode->i_sb, NOBH)) 221 inode->i_mapping->a_ops = &ext2_nobh_aops; 222 else 223 inode->i_mapping->a_ops = &ext2_aops; 224 225 inode_inc_link_count(inode); 226 227 err = ext2_make_empty(inode, dir); 228 if (err) 229 goto out_fail; 230 231 err = ext2_add_link(dentry, inode); 232 if (err) 233 goto out_fail; 234 235 d_instantiate(dentry, inode); 236 unlock_new_inode(inode); 237 out: 238 return err; 239 240 out_fail: 241 inode_dec_link_count(inode); 242 inode_dec_link_count(inode); 243 unlock_new_inode(inode); 244 iput(inode); 245 out_dir: 246 inode_dec_link_count(dir); 247 goto out; 248 } 249 250 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 251 { 252 struct inode * inode = dentry->d_inode; 253 struct ext2_dir_entry_2 * de; 254 struct page * page; 255 int err = -ENOENT; 256 257 de = ext2_find_entry (dir, &dentry->d_name, &page); 258 if (!de) 259 goto out; 260 261 err = ext2_delete_entry (de, page); 262 if (err) 263 goto out; 264 265 inode->i_ctime = dir->i_ctime; 266 inode_dec_link_count(inode); 267 err = 0; 268 out: 269 return err; 270 } 271 272 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 273 { 274 struct inode * inode = dentry->d_inode; 275 int err = -ENOTEMPTY; 276 277 if (ext2_empty_dir(inode)) { 278 err = ext2_unlink(dir, dentry); 279 if (!err) { 280 inode->i_size = 0; 281 inode_dec_link_count(inode); 282 inode_dec_link_count(dir); 283 } 284 } 285 return err; 286 } 287 288 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 289 struct inode * new_dir, struct dentry * new_dentry ) 290 { 291 struct inode * old_inode = old_dentry->d_inode; 292 struct inode * new_inode = new_dentry->d_inode; 293 struct page * dir_page = NULL; 294 struct ext2_dir_entry_2 * dir_de = NULL; 295 struct page * old_page; 296 struct ext2_dir_entry_2 * old_de; 297 int err = -ENOENT; 298 299 old_de = ext2_find_entry (old_dir, &old_dentry->d_name, &old_page); 300 if (!old_de) 301 goto out; 302 303 if (S_ISDIR(old_inode->i_mode)) { 304 err = -EIO; 305 dir_de = ext2_dotdot(old_inode, &dir_page); 306 if (!dir_de) 307 goto out_old; 308 } 309 310 if (new_inode) { 311 struct page *new_page; 312 struct ext2_dir_entry_2 *new_de; 313 314 err = -ENOTEMPTY; 315 if (dir_de && !ext2_empty_dir (new_inode)) 316 goto out_dir; 317 318 err = -ENOENT; 319 new_de = ext2_find_entry (new_dir, &new_dentry->d_name, &new_page); 320 if (!new_de) 321 goto out_dir; 322 inode_inc_link_count(old_inode); 323 ext2_set_link(new_dir, new_de, new_page, old_inode); 324 new_inode->i_ctime = CURRENT_TIME_SEC; 325 if (dir_de) 326 drop_nlink(new_inode); 327 inode_dec_link_count(new_inode); 328 } else { 329 if (dir_de) { 330 err = -EMLINK; 331 if (new_dir->i_nlink >= EXT2_LINK_MAX) 332 goto out_dir; 333 } 334 inode_inc_link_count(old_inode); 335 err = ext2_add_link(new_dentry, old_inode); 336 if (err) { 337 inode_dec_link_count(old_inode); 338 goto out_dir; 339 } 340 if (dir_de) 341 inode_inc_link_count(new_dir); 342 } 343 344 /* 345 * Like most other Unix systems, set the ctime for inodes on a 346 * rename. 347 * inode_dec_link_count() will mark the inode dirty. 348 */ 349 old_inode->i_ctime = CURRENT_TIME_SEC; 350 351 ext2_delete_entry (old_de, old_page); 352 inode_dec_link_count(old_inode); 353 354 if (dir_de) { 355 ext2_set_link(old_inode, dir_de, dir_page, new_dir); 356 inode_dec_link_count(old_dir); 357 } 358 return 0; 359 360 361 out_dir: 362 if (dir_de) { 363 kunmap(dir_page); 364 page_cache_release(dir_page); 365 } 366 out_old: 367 kunmap(old_page); 368 page_cache_release(old_page); 369 out: 370 return err; 371 } 372 373 const struct inode_operations ext2_dir_inode_operations = { 374 .create = ext2_create, 375 .lookup = ext2_lookup, 376 .link = ext2_link, 377 .unlink = ext2_unlink, 378 .symlink = ext2_symlink, 379 .mkdir = ext2_mkdir, 380 .rmdir = ext2_rmdir, 381 .mknod = ext2_mknod, 382 .rename = ext2_rename, 383 #ifdef CONFIG_EXT2_FS_XATTR 384 .setxattr = generic_setxattr, 385 .getxattr = generic_getxattr, 386 .listxattr = ext2_listxattr, 387 .removexattr = generic_removexattr, 388 #endif 389 .setattr = ext2_setattr, 390 .permission = ext2_permission, 391 }; 392 393 const struct inode_operations ext2_special_inode_operations = { 394 #ifdef CONFIG_EXT2_FS_XATTR 395 .setxattr = generic_setxattr, 396 .getxattr = generic_getxattr, 397 .listxattr = ext2_listxattr, 398 .removexattr = generic_removexattr, 399 #endif 400 .setattr = ext2_setattr, 401 .permission = ext2_permission, 402 }; 403