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 return 0; 45 } 46 inode_dec_link_count(inode); 47 iput(inode); 48 return err; 49 } 50 51 /* 52 * Methods themselves. 53 */ 54 55 static struct dentry *ext2_lookup(struct inode * dir, struct dentry *dentry, struct nameidata *nd) 56 { 57 struct inode * inode; 58 ino_t ino; 59 60 if (dentry->d_name.len > EXT2_NAME_LEN) 61 return ERR_PTR(-ENAMETOOLONG); 62 63 ino = ext2_inode_by_name(dir, dentry); 64 inode = NULL; 65 if (ino) { 66 inode = iget(dir->i_sb, ino); 67 if (!inode) 68 return ERR_PTR(-EACCES); 69 } 70 return d_splice_alias(inode, dentry); 71 } 72 73 struct dentry *ext2_get_parent(struct dentry *child) 74 { 75 unsigned long ino; 76 struct dentry *parent; 77 struct inode *inode; 78 struct dentry dotdot; 79 80 dotdot.d_name.name = ".."; 81 dotdot.d_name.len = 2; 82 83 ino = ext2_inode_by_name(child->d_inode, &dotdot); 84 if (!ino) 85 return ERR_PTR(-ENOENT); 86 inode = iget(child->d_inode->i_sb, ino); 87 88 if (!inode) 89 return ERR_PTR(-EACCES); 90 parent = d_alloc_anon(inode); 91 if (!parent) { 92 iput(inode); 93 parent = ERR_PTR(-ENOMEM); 94 } 95 return parent; 96 } 97 98 /* 99 * By the time this is called, we already have created 100 * the directory cache entry for the new file, but it 101 * is so far negative - it has no inode. 102 * 103 * If the create succeeds, we fill in the inode information 104 * with d_instantiate(). 105 */ 106 static int ext2_create (struct inode * dir, struct dentry * dentry, int mode, struct nameidata *nd) 107 { 108 struct inode * inode = ext2_new_inode (dir, mode); 109 int err = PTR_ERR(inode); 110 if (!IS_ERR(inode)) { 111 inode->i_op = &ext2_file_inode_operations; 112 if (ext2_use_xip(inode->i_sb)) { 113 inode->i_mapping->a_ops = &ext2_aops_xip; 114 inode->i_fop = &ext2_xip_file_operations; 115 } else if (test_opt(inode->i_sb, NOBH)) { 116 inode->i_mapping->a_ops = &ext2_nobh_aops; 117 inode->i_fop = &ext2_file_operations; 118 } else { 119 inode->i_mapping->a_ops = &ext2_aops; 120 inode->i_fop = &ext2_file_operations; 121 } 122 mark_inode_dirty(inode); 123 err = ext2_add_nondir(dentry, inode); 124 } 125 return err; 126 } 127 128 static int ext2_mknod (struct inode * dir, struct dentry *dentry, int mode, dev_t rdev) 129 { 130 struct inode * inode; 131 int err; 132 133 if (!new_valid_dev(rdev)) 134 return -EINVAL; 135 136 inode = ext2_new_inode (dir, mode); 137 err = PTR_ERR(inode); 138 if (!IS_ERR(inode)) { 139 init_special_inode(inode, inode->i_mode, rdev); 140 #ifdef CONFIG_EXT2_FS_XATTR 141 inode->i_op = &ext2_special_inode_operations; 142 #endif 143 mark_inode_dirty(inode); 144 err = ext2_add_nondir(dentry, inode); 145 } 146 return err; 147 } 148 149 static int ext2_symlink (struct inode * dir, struct dentry * dentry, 150 const char * symname) 151 { 152 struct super_block * sb = dir->i_sb; 153 int err = -ENAMETOOLONG; 154 unsigned l = strlen(symname)+1; 155 struct inode * inode; 156 157 if (l > sb->s_blocksize) 158 goto out; 159 160 inode = ext2_new_inode (dir, S_IFLNK | S_IRWXUGO); 161 err = PTR_ERR(inode); 162 if (IS_ERR(inode)) 163 goto out; 164 165 if (l > sizeof (EXT2_I(inode)->i_data)) { 166 /* slow symlink */ 167 inode->i_op = &ext2_symlink_inode_operations; 168 if (test_opt(inode->i_sb, NOBH)) 169 inode->i_mapping->a_ops = &ext2_nobh_aops; 170 else 171 inode->i_mapping->a_ops = &ext2_aops; 172 err = page_symlink(inode, symname, l); 173 if (err) 174 goto out_fail; 175 } else { 176 /* fast symlink */ 177 inode->i_op = &ext2_fast_symlink_inode_operations; 178 memcpy((char*)(EXT2_I(inode)->i_data),symname,l); 179 inode->i_size = l-1; 180 } 181 mark_inode_dirty(inode); 182 183 err = ext2_add_nondir(dentry, inode); 184 out: 185 return err; 186 187 out_fail: 188 inode_dec_link_count(inode); 189 iput (inode); 190 goto out; 191 } 192 193 static int ext2_link (struct dentry * old_dentry, struct inode * dir, 194 struct dentry *dentry) 195 { 196 struct inode *inode = old_dentry->d_inode; 197 198 if (inode->i_nlink >= EXT2_LINK_MAX) 199 return -EMLINK; 200 201 inode->i_ctime = CURRENT_TIME_SEC; 202 inode_inc_link_count(inode); 203 atomic_inc(&inode->i_count); 204 205 return ext2_add_nondir(dentry, inode); 206 } 207 208 static int ext2_mkdir(struct inode * dir, struct dentry * dentry, int mode) 209 { 210 struct inode * inode; 211 int err = -EMLINK; 212 213 if (dir->i_nlink >= EXT2_LINK_MAX) 214 goto out; 215 216 inode_inc_link_count(dir); 217 218 inode = ext2_new_inode (dir, S_IFDIR | mode); 219 err = PTR_ERR(inode); 220 if (IS_ERR(inode)) 221 goto out_dir; 222 223 inode->i_op = &ext2_dir_inode_operations; 224 inode->i_fop = &ext2_dir_operations; 225 if (test_opt(inode->i_sb, NOBH)) 226 inode->i_mapping->a_ops = &ext2_nobh_aops; 227 else 228 inode->i_mapping->a_ops = &ext2_aops; 229 230 inode_inc_link_count(inode); 231 232 err = ext2_make_empty(inode, dir); 233 if (err) 234 goto out_fail; 235 236 err = ext2_add_link(dentry, inode); 237 if (err) 238 goto out_fail; 239 240 d_instantiate(dentry, inode); 241 out: 242 return err; 243 244 out_fail: 245 inode_dec_link_count(inode); 246 inode_dec_link_count(inode); 247 iput(inode); 248 out_dir: 249 inode_dec_link_count(dir); 250 goto out; 251 } 252 253 static int ext2_unlink(struct inode * dir, struct dentry *dentry) 254 { 255 struct inode * inode = dentry->d_inode; 256 struct ext2_dir_entry_2 * de; 257 struct page * page; 258 int err = -ENOENT; 259 260 de = ext2_find_entry (dir, dentry, &page); 261 if (!de) 262 goto out; 263 264 err = ext2_delete_entry (de, page); 265 if (err) 266 goto out; 267 268 inode->i_ctime = dir->i_ctime; 269 inode_dec_link_count(inode); 270 err = 0; 271 out: 272 return err; 273 } 274 275 static int ext2_rmdir (struct inode * dir, struct dentry *dentry) 276 { 277 struct inode * inode = dentry->d_inode; 278 int err = -ENOTEMPTY; 279 280 if (ext2_empty_dir(inode)) { 281 err = ext2_unlink(dir, dentry); 282 if (!err) { 283 inode->i_size = 0; 284 inode_dec_link_count(inode); 285 inode_dec_link_count(dir); 286 } 287 } 288 return err; 289 } 290 291 static int ext2_rename (struct inode * old_dir, struct dentry * old_dentry, 292 struct inode * new_dir, struct dentry * new_dentry ) 293 { 294 struct inode * old_inode = old_dentry->d_inode; 295 struct inode * new_inode = new_dentry->d_inode; 296 struct page * dir_page = NULL; 297 struct ext2_dir_entry_2 * dir_de = NULL; 298 struct page * old_page; 299 struct ext2_dir_entry_2 * old_de; 300 int err = -ENOENT; 301 302 old_de = ext2_find_entry (old_dir, old_dentry, &old_page); 303 if (!old_de) 304 goto out; 305 306 if (S_ISDIR(old_inode->i_mode)) { 307 err = -EIO; 308 dir_de = ext2_dotdot(old_inode, &dir_page); 309 if (!dir_de) 310 goto out_old; 311 } 312 313 if (new_inode) { 314 struct page *new_page; 315 struct ext2_dir_entry_2 *new_de; 316 317 err = -ENOTEMPTY; 318 if (dir_de && !ext2_empty_dir (new_inode)) 319 goto out_dir; 320 321 err = -ENOENT; 322 new_de = ext2_find_entry (new_dir, new_dentry, &new_page); 323 if (!new_de) 324 goto out_dir; 325 inode_inc_link_count(old_inode); 326 ext2_set_link(new_dir, new_de, new_page, old_inode); 327 new_inode->i_ctime = CURRENT_TIME_SEC; 328 if (dir_de) 329 new_inode->i_nlink--; 330 inode_dec_link_count(new_inode); 331 } else { 332 if (dir_de) { 333 err = -EMLINK; 334 if (new_dir->i_nlink >= EXT2_LINK_MAX) 335 goto out_dir; 336 } 337 inode_inc_link_count(old_inode); 338 err = ext2_add_link(new_dentry, old_inode); 339 if (err) { 340 inode_dec_link_count(old_inode); 341 goto out_dir; 342 } 343 if (dir_de) 344 inode_inc_link_count(new_dir); 345 } 346 347 /* 348 * Like most other Unix systems, set the ctime for inodes on a 349 * rename. 350 * inode_dec_link_count() will mark the inode dirty. 351 */ 352 old_inode->i_ctime = CURRENT_TIME_SEC; 353 354 ext2_delete_entry (old_de, old_page); 355 inode_dec_link_count(old_inode); 356 357 if (dir_de) { 358 ext2_set_link(old_inode, dir_de, dir_page, new_dir); 359 inode_dec_link_count(old_dir); 360 } 361 return 0; 362 363 364 out_dir: 365 if (dir_de) { 366 kunmap(dir_page); 367 page_cache_release(dir_page); 368 } 369 out_old: 370 kunmap(old_page); 371 page_cache_release(old_page); 372 out: 373 return err; 374 } 375 376 struct inode_operations ext2_dir_inode_operations = { 377 .create = ext2_create, 378 .lookup = ext2_lookup, 379 .link = ext2_link, 380 .unlink = ext2_unlink, 381 .symlink = ext2_symlink, 382 .mkdir = ext2_mkdir, 383 .rmdir = ext2_rmdir, 384 .mknod = ext2_mknod, 385 .rename = ext2_rename, 386 #ifdef CONFIG_EXT2_FS_XATTR 387 .setxattr = generic_setxattr, 388 .getxattr = generic_getxattr, 389 .listxattr = ext2_listxattr, 390 .removexattr = generic_removexattr, 391 #endif 392 .setattr = ext2_setattr, 393 .permission = ext2_permission, 394 }; 395 396 struct inode_operations ext2_special_inode_operations = { 397 #ifdef CONFIG_EXT2_FS_XATTR 398 .setxattr = generic_setxattr, 399 .getxattr = generic_getxattr, 400 .listxattr = ext2_listxattr, 401 .removexattr = generic_removexattr, 402 #endif 403 .setattr = ext2_setattr, 404 .permission = ext2_permission, 405 }; 406