1 /* 2 * linux/fs/reiserfs/xattr.c 3 * 4 * Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com> 5 * 6 */ 7 8 /* 9 * In order to implement EA/ACLs in a clean, backwards compatible manner, 10 * they are implemented as files in a "private" directory. 11 * Each EA is in it's own file, with the directory layout like so (/ is assumed 12 * to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory, 13 * directories named using the capital-hex form of the objectid and 14 * generation number are used. Inside each directory are individual files 15 * named with the name of the extended attribute. 16 * 17 * So, for objectid 12648430, we could have: 18 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access 19 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default 20 * /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type 21 * .. or similar. 22 * 23 * The file contents are the text of the EA. The size is known based on the 24 * stat data describing the file. 25 * 26 * In the case of system.posix_acl_access and system.posix_acl_default, since 27 * these are special cases for filesystem ACLs, they are interpreted by the 28 * kernel, in addition, they are negatively and positively cached and attached 29 * to the inode so that unnecessary lookups are avoided. 30 * 31 * Locking works like so: 32 * Directory components (xattr root, xattr dir) are protectd by their i_mutex. 33 * The xattrs themselves are protected by the xattr_sem. 34 */ 35 36 #include <linux/reiserfs_fs.h> 37 #include <linux/capability.h> 38 #include <linux/dcache.h> 39 #include <linux/namei.h> 40 #include <linux/errno.h> 41 #include <linux/gfp.h> 42 #include <linux/fs.h> 43 #include <linux/file.h> 44 #include <linux/pagemap.h> 45 #include <linux/xattr.h> 46 #include <linux/reiserfs_xattr.h> 47 #include <linux/reiserfs_acl.h> 48 #include <asm/uaccess.h> 49 #include <net/checksum.h> 50 #include <linux/stat.h> 51 #include <linux/quotaops.h> 52 #include <linux/security.h> 53 54 #define PRIVROOT_NAME ".reiserfs_priv" 55 #define XAROOT_NAME "xattrs" 56 57 58 /* Helpers for inode ops. We do this so that we don't have all the VFS 59 * overhead and also for proper i_mutex annotation. 60 * dir->i_mutex must be held for all of them. */ 61 #ifdef CONFIG_REISERFS_FS_XATTR 62 static int xattr_create(struct inode *dir, struct dentry *dentry, int mode) 63 { 64 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 65 return dir->i_op->create(dir, dentry, mode, NULL); 66 } 67 #endif 68 69 static int xattr_mkdir(struct inode *dir, struct dentry *dentry, int mode) 70 { 71 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 72 return dir->i_op->mkdir(dir, dentry, mode); 73 } 74 75 /* We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr 76 * mutation ops aren't called during rename or splace, which are the 77 * only other users of I_MUTEX_CHILD. It violates the ordering, but that's 78 * better than allocating another subclass just for this code. */ 79 static int xattr_unlink(struct inode *dir, struct dentry *dentry) 80 { 81 int error; 82 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 83 84 reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex, 85 I_MUTEX_CHILD, dir->i_sb); 86 error = dir->i_op->unlink(dir, dentry); 87 mutex_unlock(&dentry->d_inode->i_mutex); 88 89 if (!error) 90 d_delete(dentry); 91 return error; 92 } 93 94 static int xattr_rmdir(struct inode *dir, struct dentry *dentry) 95 { 96 int error; 97 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 98 99 reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex, 100 I_MUTEX_CHILD, dir->i_sb); 101 dentry_unhash(dentry); 102 error = dir->i_op->rmdir(dir, dentry); 103 if (!error) 104 dentry->d_inode->i_flags |= S_DEAD; 105 mutex_unlock(&dentry->d_inode->i_mutex); 106 if (!error) 107 d_delete(dentry); 108 109 return error; 110 } 111 112 #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE) 113 114 static struct dentry *open_xa_root(struct super_block *sb, int flags) 115 { 116 struct dentry *privroot = REISERFS_SB(sb)->priv_root; 117 struct dentry *xaroot; 118 if (!privroot->d_inode) 119 return ERR_PTR(-ENODATA); 120 121 mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR); 122 123 xaroot = dget(REISERFS_SB(sb)->xattr_root); 124 if (!xaroot) 125 xaroot = ERR_PTR(-ENODATA); 126 else if (!xaroot->d_inode) { 127 int err = -ENODATA; 128 if (xattr_may_create(flags)) 129 err = xattr_mkdir(privroot->d_inode, xaroot, 0700); 130 if (err) { 131 dput(xaroot); 132 xaroot = ERR_PTR(err); 133 } 134 } 135 136 mutex_unlock(&privroot->d_inode->i_mutex); 137 return xaroot; 138 } 139 140 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 141 { 142 struct dentry *xaroot, *xadir; 143 char namebuf[17]; 144 145 xaroot = open_xa_root(inode->i_sb, flags); 146 if (IS_ERR(xaroot)) 147 return xaroot; 148 149 snprintf(namebuf, sizeof(namebuf), "%X.%X", 150 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 151 inode->i_generation); 152 153 mutex_lock_nested(&xaroot->d_inode->i_mutex, I_MUTEX_XATTR); 154 155 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); 156 if (!IS_ERR(xadir) && !xadir->d_inode) { 157 int err = -ENODATA; 158 if (xattr_may_create(flags)) 159 err = xattr_mkdir(xaroot->d_inode, xadir, 0700); 160 if (err) { 161 dput(xadir); 162 xadir = ERR_PTR(err); 163 } 164 } 165 166 mutex_unlock(&xaroot->d_inode->i_mutex); 167 dput(xaroot); 168 return xadir; 169 } 170 171 /* The following are side effects of other operations that aren't explicitly 172 * modifying extended attributes. This includes operations such as permissions 173 * or ownership changes, object deletions, etc. */ 174 struct reiserfs_dentry_buf { 175 struct dentry *xadir; 176 int count; 177 struct dentry *dentries[8]; 178 }; 179 180 static int 181 fill_with_dentries(void *buf, const char *name, int namelen, loff_t offset, 182 u64 ino, unsigned int d_type) 183 { 184 struct reiserfs_dentry_buf *dbuf = buf; 185 struct dentry *dentry; 186 WARN_ON_ONCE(!mutex_is_locked(&dbuf->xadir->d_inode->i_mutex)); 187 188 if (dbuf->count == ARRAY_SIZE(dbuf->dentries)) 189 return -ENOSPC; 190 191 if (name[0] == '.' && (name[1] == '\0' || 192 (name[1] == '.' && name[2] == '\0'))) 193 return 0; 194 195 dentry = lookup_one_len(name, dbuf->xadir, namelen); 196 if (IS_ERR(dentry)) { 197 return PTR_ERR(dentry); 198 } else if (!dentry->d_inode) { 199 /* A directory entry exists, but no file? */ 200 reiserfs_error(dentry->d_sb, "xattr-20003", 201 "Corrupted directory: xattr %s listed but " 202 "not found for file %s.\n", 203 dentry->d_name.name, dbuf->xadir->d_name.name); 204 dput(dentry); 205 return -EIO; 206 } 207 208 dbuf->dentries[dbuf->count++] = dentry; 209 return 0; 210 } 211 212 static void 213 cleanup_dentry_buf(struct reiserfs_dentry_buf *buf) 214 { 215 int i; 216 for (i = 0; i < buf->count; i++) 217 if (buf->dentries[i]) 218 dput(buf->dentries[i]); 219 } 220 221 static int reiserfs_for_each_xattr(struct inode *inode, 222 int (*action)(struct dentry *, void *), 223 void *data) 224 { 225 struct dentry *dir; 226 int i, err = 0; 227 loff_t pos = 0; 228 struct reiserfs_dentry_buf buf = { 229 .count = 0, 230 }; 231 232 /* Skip out, an xattr has no xattrs associated with it */ 233 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 234 return 0; 235 236 reiserfs_write_unlock(inode->i_sb); 237 dir = open_xa_dir(inode, XATTR_REPLACE); 238 if (IS_ERR(dir)) { 239 err = PTR_ERR(dir); 240 reiserfs_write_lock(inode->i_sb); 241 goto out; 242 } else if (!dir->d_inode) { 243 err = 0; 244 reiserfs_write_lock(inode->i_sb); 245 goto out_dir; 246 } 247 248 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 249 250 reiserfs_write_lock(inode->i_sb); 251 252 buf.xadir = dir; 253 err = reiserfs_readdir_dentry(dir, &buf, fill_with_dentries, &pos); 254 while ((err == 0 || err == -ENOSPC) && buf.count) { 255 err = 0; 256 257 for (i = 0; i < buf.count && buf.dentries[i]; i++) { 258 int lerr = 0; 259 struct dentry *dentry = buf.dentries[i]; 260 261 if (err == 0 && !S_ISDIR(dentry->d_inode->i_mode)) 262 lerr = action(dentry, data); 263 264 dput(dentry); 265 buf.dentries[i] = NULL; 266 err = lerr ?: err; 267 } 268 buf.count = 0; 269 if (!err) 270 err = reiserfs_readdir_dentry(dir, &buf, 271 fill_with_dentries, &pos); 272 } 273 mutex_unlock(&dir->d_inode->i_mutex); 274 275 /* Clean up after a failed readdir */ 276 cleanup_dentry_buf(&buf); 277 278 if (!err) { 279 /* We start a transaction here to avoid a ABBA situation 280 * between the xattr root's i_mutex and the journal lock. 281 * This doesn't incur much additional overhead since the 282 * new transaction will just nest inside the 283 * outer transaction. */ 284 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 285 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); 286 struct reiserfs_transaction_handle th; 287 err = journal_begin(&th, inode->i_sb, blocks); 288 if (!err) { 289 int jerror; 290 reiserfs_mutex_lock_nested_safe( 291 &dir->d_parent->d_inode->i_mutex, 292 I_MUTEX_XATTR, inode->i_sb); 293 err = action(dir, data); 294 jerror = journal_end(&th, inode->i_sb, blocks); 295 mutex_unlock(&dir->d_parent->d_inode->i_mutex); 296 err = jerror ?: err; 297 } 298 } 299 out_dir: 300 dput(dir); 301 out: 302 /* -ENODATA isn't an error */ 303 if (err == -ENODATA) 304 err = 0; 305 return err; 306 } 307 308 static int delete_one_xattr(struct dentry *dentry, void *data) 309 { 310 struct inode *dir = dentry->d_parent->d_inode; 311 312 /* This is the xattr dir, handle specially. */ 313 if (S_ISDIR(dentry->d_inode->i_mode)) 314 return xattr_rmdir(dir, dentry); 315 316 return xattr_unlink(dir, dentry); 317 } 318 319 static int chown_one_xattr(struct dentry *dentry, void *data) 320 { 321 struct iattr *attrs = data; 322 return reiserfs_setattr(dentry, attrs); 323 } 324 325 /* No i_mutex, but the inode is unconnected. */ 326 int reiserfs_delete_xattrs(struct inode *inode) 327 { 328 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL); 329 if (err) 330 reiserfs_warning(inode->i_sb, "jdm-20004", 331 "Couldn't delete all xattrs (%d)\n", err); 332 return err; 333 } 334 335 /* inode->i_mutex: down */ 336 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 337 { 338 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs); 339 if (err) 340 reiserfs_warning(inode->i_sb, "jdm-20007", 341 "Couldn't chown all xattrs (%d)\n", err); 342 return err; 343 } 344 345 #ifdef CONFIG_REISERFS_FS_XATTR 346 /* Returns a dentry corresponding to a specific extended attribute file 347 * for the inode. If flags allow, the file is created. Otherwise, a 348 * valid or negative dentry, or an error is returned. */ 349 static struct dentry *xattr_lookup(struct inode *inode, const char *name, 350 int flags) 351 { 352 struct dentry *xadir, *xafile; 353 int err = 0; 354 355 xadir = open_xa_dir(inode, flags); 356 if (IS_ERR(xadir)) 357 return ERR_CAST(xadir); 358 359 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 360 xafile = lookup_one_len(name, xadir, strlen(name)); 361 if (IS_ERR(xafile)) { 362 err = PTR_ERR(xafile); 363 goto out; 364 } 365 366 if (xafile->d_inode && (flags & XATTR_CREATE)) 367 err = -EEXIST; 368 369 if (!xafile->d_inode) { 370 err = -ENODATA; 371 if (xattr_may_create(flags)) 372 err = xattr_create(xadir->d_inode, xafile, 373 0700|S_IFREG); 374 } 375 376 if (err) 377 dput(xafile); 378 out: 379 mutex_unlock(&xadir->d_inode->i_mutex); 380 dput(xadir); 381 if (err) 382 return ERR_PTR(err); 383 return xafile; 384 } 385 386 /* Internal operations on file data */ 387 static inline void reiserfs_put_page(struct page *page) 388 { 389 kunmap(page); 390 page_cache_release(page); 391 } 392 393 static struct page *reiserfs_get_page(struct inode *dir, size_t n) 394 { 395 struct address_space *mapping = dir->i_mapping; 396 struct page *page; 397 /* We can deadlock if we try to free dentries, 398 and an unlink/rmdir has just occurred - GFP_NOFS avoids this */ 399 mapping_set_gfp_mask(mapping, GFP_NOFS); 400 page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); 401 if (!IS_ERR(page)) { 402 kmap(page); 403 if (PageError(page)) 404 goto fail; 405 } 406 return page; 407 408 fail: 409 reiserfs_put_page(page); 410 return ERR_PTR(-EIO); 411 } 412 413 static inline __u32 xattr_hash(const char *msg, int len) 414 { 415 return csum_partial(msg, len, 0); 416 } 417 418 int reiserfs_commit_write(struct file *f, struct page *page, 419 unsigned from, unsigned to); 420 421 static void update_ctime(struct inode *inode) 422 { 423 struct timespec now = current_fs_time(inode->i_sb); 424 if (inode_unhashed(inode) || !inode->i_nlink || 425 timespec_equal(&inode->i_ctime, &now)) 426 return; 427 428 inode->i_ctime = CURRENT_TIME_SEC; 429 mark_inode_dirty(inode); 430 } 431 432 static int lookup_and_delete_xattr(struct inode *inode, const char *name) 433 { 434 int err = 0; 435 struct dentry *dentry, *xadir; 436 437 xadir = open_xa_dir(inode, XATTR_REPLACE); 438 if (IS_ERR(xadir)) 439 return PTR_ERR(xadir); 440 441 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 442 dentry = lookup_one_len(name, xadir, strlen(name)); 443 if (IS_ERR(dentry)) { 444 err = PTR_ERR(dentry); 445 goto out_dput; 446 } 447 448 if (dentry->d_inode) { 449 reiserfs_write_lock(inode->i_sb); 450 err = xattr_unlink(xadir->d_inode, dentry); 451 reiserfs_write_unlock(inode->i_sb); 452 update_ctime(inode); 453 } 454 455 dput(dentry); 456 out_dput: 457 mutex_unlock(&xadir->d_inode->i_mutex); 458 dput(xadir); 459 return err; 460 } 461 462 463 /* Generic extended attribute operations that can be used by xa plugins */ 464 465 /* 466 * inode->i_mutex: down 467 */ 468 int 469 reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th, 470 struct inode *inode, const char *name, 471 const void *buffer, size_t buffer_size, int flags) 472 { 473 int err = 0; 474 struct dentry *dentry; 475 struct page *page; 476 char *data; 477 size_t file_pos = 0; 478 size_t buffer_pos = 0; 479 size_t new_size; 480 __u32 xahash = 0; 481 482 if (get_inode_sd_version(inode) == STAT_DATA_V1) 483 return -EOPNOTSUPP; 484 485 reiserfs_write_unlock(inode->i_sb); 486 487 if (!buffer) { 488 err = lookup_and_delete_xattr(inode, name); 489 reiserfs_write_lock(inode->i_sb); 490 return err; 491 } 492 493 dentry = xattr_lookup(inode, name, flags); 494 if (IS_ERR(dentry)) { 495 reiserfs_write_lock(inode->i_sb); 496 return PTR_ERR(dentry); 497 } 498 499 down_write(&REISERFS_I(inode)->i_xattr_sem); 500 501 reiserfs_write_lock(inode->i_sb); 502 503 xahash = xattr_hash(buffer, buffer_size); 504 while (buffer_pos < buffer_size || buffer_pos == 0) { 505 size_t chunk; 506 size_t skip = 0; 507 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 508 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 509 chunk = PAGE_CACHE_SIZE; 510 else 511 chunk = buffer_size - buffer_pos; 512 513 page = reiserfs_get_page(dentry->d_inode, file_pos); 514 if (IS_ERR(page)) { 515 err = PTR_ERR(page); 516 goto out_unlock; 517 } 518 519 lock_page(page); 520 data = page_address(page); 521 522 if (file_pos == 0) { 523 struct reiserfs_xattr_header *rxh; 524 skip = file_pos = sizeof(struct reiserfs_xattr_header); 525 if (chunk + skip > PAGE_CACHE_SIZE) 526 chunk = PAGE_CACHE_SIZE - skip; 527 rxh = (struct reiserfs_xattr_header *)data; 528 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 529 rxh->h_hash = cpu_to_le32(xahash); 530 } 531 532 err = __reiserfs_write_begin(page, page_offset, chunk + skip); 533 if (!err) { 534 if (buffer) 535 memcpy(data + skip, buffer + buffer_pos, chunk); 536 err = reiserfs_commit_write(NULL, page, page_offset, 537 page_offset + chunk + 538 skip); 539 } 540 unlock_page(page); 541 reiserfs_put_page(page); 542 buffer_pos += chunk; 543 file_pos += chunk; 544 skip = 0; 545 if (err || buffer_size == 0 || !buffer) 546 break; 547 } 548 549 new_size = buffer_size + sizeof(struct reiserfs_xattr_header); 550 if (!err && new_size < i_size_read(dentry->d_inode)) { 551 struct iattr newattrs = { 552 .ia_ctime = current_fs_time(inode->i_sb), 553 .ia_size = new_size, 554 .ia_valid = ATTR_SIZE | ATTR_CTIME, 555 }; 556 557 reiserfs_write_unlock(inode->i_sb); 558 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 559 down_write(&dentry->d_inode->i_alloc_sem); 560 reiserfs_write_lock(inode->i_sb); 561 562 err = reiserfs_setattr(dentry, &newattrs); 563 up_write(&dentry->d_inode->i_alloc_sem); 564 mutex_unlock(&dentry->d_inode->i_mutex); 565 } else 566 update_ctime(inode); 567 out_unlock: 568 up_write(&REISERFS_I(inode)->i_xattr_sem); 569 dput(dentry); 570 return err; 571 } 572 573 /* We need to start a transaction to maintain lock ordering */ 574 int reiserfs_xattr_set(struct inode *inode, const char *name, 575 const void *buffer, size_t buffer_size, int flags) 576 { 577 578 struct reiserfs_transaction_handle th; 579 int error, error2; 580 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); 581 582 if (!(flags & XATTR_REPLACE)) 583 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); 584 585 reiserfs_write_lock(inode->i_sb); 586 error = journal_begin(&th, inode->i_sb, jbegin_count); 587 if (error) { 588 reiserfs_write_unlock(inode->i_sb); 589 return error; 590 } 591 592 error = reiserfs_xattr_set_handle(&th, inode, name, 593 buffer, buffer_size, flags); 594 595 error2 = journal_end(&th, inode->i_sb, jbegin_count); 596 if (error == 0) 597 error = error2; 598 reiserfs_write_unlock(inode->i_sb); 599 600 return error; 601 } 602 603 /* 604 * inode->i_mutex: down 605 */ 606 int 607 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, 608 size_t buffer_size) 609 { 610 ssize_t err = 0; 611 struct dentry *dentry; 612 size_t isize; 613 size_t file_pos = 0; 614 size_t buffer_pos = 0; 615 struct page *page; 616 __u32 hash = 0; 617 618 if (name == NULL) 619 return -EINVAL; 620 621 /* We can't have xattrs attached to v1 items since they don't have 622 * generation numbers */ 623 if (get_inode_sd_version(inode) == STAT_DATA_V1) 624 return -EOPNOTSUPP; 625 626 dentry = xattr_lookup(inode, name, XATTR_REPLACE); 627 if (IS_ERR(dentry)) { 628 err = PTR_ERR(dentry); 629 goto out; 630 } 631 632 down_read(&REISERFS_I(inode)->i_xattr_sem); 633 634 isize = i_size_read(dentry->d_inode); 635 636 /* Just return the size needed */ 637 if (buffer == NULL) { 638 err = isize - sizeof(struct reiserfs_xattr_header); 639 goto out_unlock; 640 } 641 642 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 643 err = -ERANGE; 644 goto out_unlock; 645 } 646 647 while (file_pos < isize) { 648 size_t chunk; 649 char *data; 650 size_t skip = 0; 651 if (isize - file_pos > PAGE_CACHE_SIZE) 652 chunk = PAGE_CACHE_SIZE; 653 else 654 chunk = isize - file_pos; 655 656 page = reiserfs_get_page(dentry->d_inode, file_pos); 657 if (IS_ERR(page)) { 658 err = PTR_ERR(page); 659 goto out_unlock; 660 } 661 662 lock_page(page); 663 data = page_address(page); 664 if (file_pos == 0) { 665 struct reiserfs_xattr_header *rxh = 666 (struct reiserfs_xattr_header *)data; 667 skip = file_pos = sizeof(struct reiserfs_xattr_header); 668 chunk -= skip; 669 /* Magic doesn't match up.. */ 670 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 671 unlock_page(page); 672 reiserfs_put_page(page); 673 reiserfs_warning(inode->i_sb, "jdm-20001", 674 "Invalid magic for xattr (%s) " 675 "associated with %k", name, 676 INODE_PKEY(inode)); 677 err = -EIO; 678 goto out_unlock; 679 } 680 hash = le32_to_cpu(rxh->h_hash); 681 } 682 memcpy(buffer + buffer_pos, data + skip, chunk); 683 unlock_page(page); 684 reiserfs_put_page(page); 685 file_pos += chunk; 686 buffer_pos += chunk; 687 skip = 0; 688 } 689 err = isize - sizeof(struct reiserfs_xattr_header); 690 691 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 692 hash) { 693 reiserfs_warning(inode->i_sb, "jdm-20002", 694 "Invalid hash for xattr (%s) associated " 695 "with %k", name, INODE_PKEY(inode)); 696 err = -EIO; 697 } 698 699 out_unlock: 700 up_read(&REISERFS_I(inode)->i_xattr_sem); 701 dput(dentry); 702 703 out: 704 return err; 705 } 706 707 /* 708 * In order to implement different sets of xattr operations for each xattr 709 * prefix with the generic xattr API, a filesystem should create a 710 * null-terminated array of struct xattr_handler (one for each prefix) and 711 * hang a pointer to it off of the s_xattr field of the superblock. 712 * 713 * The generic_fooxattr() functions will use this list to dispatch xattr 714 * operations to the correct xattr_handler. 715 */ 716 #define for_each_xattr_handler(handlers, handler) \ 717 for ((handler) = *(handlers)++; \ 718 (handler) != NULL; \ 719 (handler) = *(handlers)++) 720 721 /* This is the implementation for the xattr plugin infrastructure */ 722 static inline const struct xattr_handler * 723 find_xattr_handler_prefix(const struct xattr_handler **handlers, 724 const char *name) 725 { 726 const struct xattr_handler *xah; 727 728 if (!handlers) 729 return NULL; 730 731 for_each_xattr_handler(handlers, xah) { 732 if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0) 733 break; 734 } 735 736 return xah; 737 } 738 739 740 /* 741 * Inode operation getxattr() 742 */ 743 ssize_t 744 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 745 size_t size) 746 { 747 const struct xattr_handler *handler; 748 749 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 750 751 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 752 return -EOPNOTSUPP; 753 754 return handler->get(dentry, name, buffer, size, handler->flags); 755 } 756 757 /* 758 * Inode operation setxattr() 759 * 760 * dentry->d_inode->i_mutex down 761 */ 762 int 763 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 764 size_t size, int flags) 765 { 766 const struct xattr_handler *handler; 767 768 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 769 770 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 771 return -EOPNOTSUPP; 772 773 return handler->set(dentry, name, value, size, flags, handler->flags); 774 } 775 776 /* 777 * Inode operation removexattr() 778 * 779 * dentry->d_inode->i_mutex down 780 */ 781 int reiserfs_removexattr(struct dentry *dentry, const char *name) 782 { 783 const struct xattr_handler *handler; 784 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 785 786 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 787 return -EOPNOTSUPP; 788 789 return handler->set(dentry, name, NULL, 0, XATTR_REPLACE, handler->flags); 790 } 791 792 struct listxattr_buf { 793 size_t size; 794 size_t pos; 795 char *buf; 796 struct dentry *dentry; 797 }; 798 799 static int listxattr_filler(void *buf, const char *name, int namelen, 800 loff_t offset, u64 ino, unsigned int d_type) 801 { 802 struct listxattr_buf *b = (struct listxattr_buf *)buf; 803 size_t size; 804 if (name[0] != '.' || 805 (namelen != 1 && (name[1] != '.' || namelen != 2))) { 806 const struct xattr_handler *handler; 807 handler = find_xattr_handler_prefix(b->dentry->d_sb->s_xattr, 808 name); 809 if (!handler) /* Unsupported xattr name */ 810 return 0; 811 if (b->buf) { 812 size = handler->list(b->dentry, b->buf + b->pos, 813 b->size, name, namelen, 814 handler->flags); 815 if (size > b->size) 816 return -ERANGE; 817 } else { 818 size = handler->list(b->dentry, NULL, 0, name, 819 namelen, handler->flags); 820 } 821 822 b->pos += size; 823 } 824 return 0; 825 } 826 827 /* 828 * Inode operation listxattr() 829 * 830 * We totally ignore the generic listxattr here because it would be stupid 831 * not to. Since the xattrs are organized in a directory, we can just 832 * readdir to find them. 833 */ 834 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 835 { 836 struct dentry *dir; 837 int err = 0; 838 loff_t pos = 0; 839 struct listxattr_buf buf = { 840 .dentry = dentry, 841 .buf = buffer, 842 .size = buffer ? size : 0, 843 }; 844 845 if (!dentry->d_inode) 846 return -EINVAL; 847 848 if (!dentry->d_sb->s_xattr || 849 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 850 return -EOPNOTSUPP; 851 852 dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); 853 if (IS_ERR(dir)) { 854 err = PTR_ERR(dir); 855 if (err == -ENODATA) 856 err = 0; /* Not an error if there aren't any xattrs */ 857 goto out; 858 } 859 860 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 861 err = reiserfs_readdir_dentry(dir, &buf, listxattr_filler, &pos); 862 mutex_unlock(&dir->d_inode->i_mutex); 863 864 if (!err) 865 err = buf.pos; 866 867 dput(dir); 868 out: 869 return err; 870 } 871 872 static int reiserfs_check_acl(struct inode *inode, int mask, unsigned int flags) 873 { 874 struct posix_acl *acl; 875 int error = -EAGAIN; /* do regular unix permission checks by default */ 876 877 if (flags & IPERM_FLAG_RCU) 878 return -ECHILD; 879 880 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 881 882 if (acl) { 883 if (!IS_ERR(acl)) { 884 error = posix_acl_permission(inode, acl, mask); 885 posix_acl_release(acl); 886 } else if (PTR_ERR(acl) != -ENODATA) 887 error = PTR_ERR(acl); 888 } 889 890 return error; 891 } 892 893 static int create_privroot(struct dentry *dentry) 894 { 895 int err; 896 struct inode *inode = dentry->d_parent->d_inode; 897 WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex)); 898 899 err = xattr_mkdir(inode, dentry, 0700); 900 if (err || !dentry->d_inode) { 901 reiserfs_warning(dentry->d_sb, "jdm-20006", 902 "xattrs/ACLs enabled and couldn't " 903 "find/create .reiserfs_priv. " 904 "Failing mount."); 905 return -EOPNOTSUPP; 906 } 907 908 dentry->d_inode->i_flags |= S_PRIVATE; 909 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 910 "storage.\n", PRIVROOT_NAME); 911 912 return 0; 913 } 914 915 #else 916 int __init reiserfs_xattr_register_handlers(void) { return 0; } 917 void reiserfs_xattr_unregister_handlers(void) {} 918 static int create_privroot(struct dentry *dentry) { return 0; } 919 #endif 920 921 /* Actual operations that are exported to VFS-land */ 922 const struct xattr_handler *reiserfs_xattr_handlers[] = { 923 #ifdef CONFIG_REISERFS_FS_XATTR 924 &reiserfs_xattr_user_handler, 925 &reiserfs_xattr_trusted_handler, 926 #endif 927 #ifdef CONFIG_REISERFS_FS_SECURITY 928 &reiserfs_xattr_security_handler, 929 #endif 930 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 931 &reiserfs_posix_acl_access_handler, 932 &reiserfs_posix_acl_default_handler, 933 #endif 934 NULL 935 }; 936 937 static int xattr_mount_check(struct super_block *s) 938 { 939 /* We need generation numbers to ensure that the oid mapping is correct 940 * v3.5 filesystems don't have them. */ 941 if (old_format_only(s)) { 942 if (reiserfs_xattrs_optional(s)) { 943 /* Old format filesystem, but optional xattrs have 944 * been enabled. Error out. */ 945 reiserfs_warning(s, "jdm-2005", 946 "xattrs/ACLs not supported " 947 "on pre-v3.6 format filesystems. " 948 "Failing mount."); 949 return -EOPNOTSUPP; 950 } 951 } 952 953 return 0; 954 } 955 956 int reiserfs_permission(struct inode *inode, int mask, unsigned int flags) 957 { 958 if (flags & IPERM_FLAG_RCU) 959 return -ECHILD; 960 /* 961 * We don't do permission checks on the internal objects. 962 * Permissions are determined by the "owning" object. 963 */ 964 if (IS_PRIVATE(inode)) 965 return 0; 966 967 #ifdef CONFIG_REISERFS_FS_XATTR 968 /* 969 * Stat data v1 doesn't support ACLs. 970 */ 971 if (get_inode_sd_version(inode) != STAT_DATA_V1) 972 return generic_permission(inode, mask, flags, 973 reiserfs_check_acl); 974 #endif 975 return generic_permission(inode, mask, flags, NULL); 976 } 977 978 static int xattr_hide_revalidate(struct dentry *dentry, struct nameidata *nd) 979 { 980 return -EPERM; 981 } 982 983 static const struct dentry_operations xattr_lookup_poison_ops = { 984 .d_revalidate = xattr_hide_revalidate, 985 }; 986 987 int reiserfs_lookup_privroot(struct super_block *s) 988 { 989 struct dentry *dentry; 990 int err = 0; 991 992 /* If we don't have the privroot located yet - go find it */ 993 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 994 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 995 strlen(PRIVROOT_NAME)); 996 if (!IS_ERR(dentry)) { 997 REISERFS_SB(s)->priv_root = dentry; 998 d_set_d_op(dentry, &xattr_lookup_poison_ops); 999 if (dentry->d_inode) 1000 dentry->d_inode->i_flags |= S_PRIVATE; 1001 } else 1002 err = PTR_ERR(dentry); 1003 mutex_unlock(&s->s_root->d_inode->i_mutex); 1004 1005 return err; 1006 } 1007 1008 /* We need to take a copy of the mount flags since things like 1009 * MS_RDONLY don't get set until *after* we're called. 1010 * mount_flags != mount_options */ 1011 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1012 { 1013 int err = 0; 1014 struct dentry *privroot = REISERFS_SB(s)->priv_root; 1015 1016 err = xattr_mount_check(s); 1017 if (err) 1018 goto error; 1019 1020 if (!privroot->d_inode && !(mount_flags & MS_RDONLY)) { 1021 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 1022 err = create_privroot(REISERFS_SB(s)->priv_root); 1023 mutex_unlock(&s->s_root->d_inode->i_mutex); 1024 } 1025 1026 if (privroot->d_inode) { 1027 s->s_xattr = reiserfs_xattr_handlers; 1028 reiserfs_mutex_lock_safe(&privroot->d_inode->i_mutex, s); 1029 if (!REISERFS_SB(s)->xattr_root) { 1030 struct dentry *dentry; 1031 dentry = lookup_one_len(XAROOT_NAME, privroot, 1032 strlen(XAROOT_NAME)); 1033 if (!IS_ERR(dentry)) 1034 REISERFS_SB(s)->xattr_root = dentry; 1035 else 1036 err = PTR_ERR(dentry); 1037 } 1038 mutex_unlock(&privroot->d_inode->i_mutex); 1039 } 1040 1041 error: 1042 if (err) { 1043 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1044 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1045 } 1046 1047 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1048 if (reiserfs_posixacl(s)) 1049 s->s_flags |= MS_POSIXACL; 1050 else 1051 s->s_flags &= ~MS_POSIXACL; 1052 1053 return err; 1054 } 1055