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/fs.h> 42 #include <linux/file.h> 43 #include <linux/pagemap.h> 44 #include <linux/xattr.h> 45 #include <linux/reiserfs_xattr.h> 46 #include <linux/reiserfs_acl.h> 47 #include <asm/uaccess.h> 48 #include <net/checksum.h> 49 #include <linux/smp_lock.h> 50 #include <linux/stat.h> 51 #include <linux/quotaops.h> 52 53 #define PRIVROOT_NAME ".reiserfs_priv" 54 #define XAROOT_NAME "xattrs" 55 56 57 /* Helpers for inode ops. We do this so that we don't have all the VFS 58 * overhead and also for proper i_mutex annotation. 59 * dir->i_mutex must be held for all of them. */ 60 #ifdef CONFIG_REISERFS_FS_XATTR 61 static int xattr_create(struct inode *dir, struct dentry *dentry, int mode) 62 { 63 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 64 vfs_dq_init(dir); 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 vfs_dq_init(dir); 73 return dir->i_op->mkdir(dir, dentry, mode); 74 } 75 76 /* We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr 77 * mutation ops aren't called during rename or splace, which are the 78 * only other users of I_MUTEX_CHILD. It violates the ordering, but that's 79 * better than allocating another subclass just for this code. */ 80 static int xattr_unlink(struct inode *dir, struct dentry *dentry) 81 { 82 int error; 83 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 84 vfs_dq_init(dir); 85 86 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); 87 error = dir->i_op->unlink(dir, dentry); 88 mutex_unlock(&dentry->d_inode->i_mutex); 89 90 if (!error) 91 d_delete(dentry); 92 return error; 93 } 94 95 static int xattr_rmdir(struct inode *dir, struct dentry *dentry) 96 { 97 int error; 98 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 99 vfs_dq_init(dir); 100 101 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); 102 dentry_unhash(dentry); 103 error = dir->i_op->rmdir(dir, dentry); 104 if (!error) 105 dentry->d_inode->i_flags |= S_DEAD; 106 mutex_unlock(&dentry->d_inode->i_mutex); 107 if (!error) 108 d_delete(dentry); 109 dput(dentry); 110 111 return error; 112 } 113 114 #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE) 115 116 /* Returns and possibly creates the xattr dir. */ 117 static struct dentry *lookup_or_create_dir(struct dentry *parent, 118 const char *name, int flags) 119 { 120 struct dentry *dentry; 121 BUG_ON(!parent); 122 123 dentry = lookup_one_len(name, parent, strlen(name)); 124 if (IS_ERR(dentry)) 125 return dentry; 126 else if (!dentry->d_inode) { 127 int err = -ENODATA; 128 129 if (xattr_may_create(flags)) { 130 mutex_lock_nested(&parent->d_inode->i_mutex, 131 I_MUTEX_XATTR); 132 err = xattr_mkdir(parent->d_inode, dentry, 0700); 133 mutex_unlock(&parent->d_inode->i_mutex); 134 } 135 136 if (err) { 137 dput(dentry); 138 dentry = ERR_PTR(err); 139 } 140 } 141 142 return dentry; 143 } 144 145 static struct dentry *open_xa_root(struct super_block *sb, int flags) 146 { 147 struct dentry *privroot = REISERFS_SB(sb)->priv_root; 148 if (!privroot) 149 return ERR_PTR(-ENODATA); 150 return lookup_or_create_dir(privroot, XAROOT_NAME, flags); 151 } 152 153 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 154 { 155 struct dentry *xaroot, *xadir; 156 char namebuf[17]; 157 158 xaroot = open_xa_root(inode->i_sb, flags); 159 if (IS_ERR(xaroot)) 160 return xaroot; 161 162 snprintf(namebuf, sizeof(namebuf), "%X.%X", 163 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 164 inode->i_generation); 165 166 xadir = lookup_or_create_dir(xaroot, namebuf, flags); 167 dput(xaroot); 168 return xadir; 169 170 } 171 172 /* The following are side effects of other operations that aren't explicitly 173 * modifying extended attributes. This includes operations such as permissions 174 * or ownership changes, object deletions, etc. */ 175 struct reiserfs_dentry_buf { 176 struct dentry *xadir; 177 int count; 178 struct dentry *dentries[8]; 179 }; 180 181 static int 182 fill_with_dentries(void *buf, const char *name, int namelen, loff_t offset, 183 u64 ino, unsigned int d_type) 184 { 185 struct reiserfs_dentry_buf *dbuf = buf; 186 struct dentry *dentry; 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 dir = open_xa_dir(inode, XATTR_REPLACE); 237 if (IS_ERR(dir)) { 238 err = PTR_ERR(dir); 239 goto out; 240 } else if (!dir->d_inode) { 241 err = 0; 242 goto out_dir; 243 } 244 245 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 246 buf.xadir = dir; 247 err = reiserfs_readdir_dentry(dir, &buf, fill_with_dentries, &pos); 248 while ((err == 0 || err == -ENOSPC) && buf.count) { 249 err = 0; 250 251 for (i = 0; i < buf.count && buf.dentries[i]; i++) { 252 int lerr = 0; 253 struct dentry *dentry = buf.dentries[i]; 254 255 if (err == 0 && !S_ISDIR(dentry->d_inode->i_mode)) 256 lerr = action(dentry, data); 257 258 dput(dentry); 259 buf.dentries[i] = NULL; 260 err = lerr ?: err; 261 } 262 buf.count = 0; 263 if (!err) 264 err = reiserfs_readdir_dentry(dir, &buf, 265 fill_with_dentries, &pos); 266 } 267 mutex_unlock(&dir->d_inode->i_mutex); 268 269 /* Clean up after a failed readdir */ 270 cleanup_dentry_buf(&buf); 271 272 if (!err) { 273 /* We start a transaction here to avoid a ABBA situation 274 * between the xattr root's i_mutex and the journal lock. 275 * This doesn't incur much additional overhead since the 276 * new transaction will just nest inside the 277 * outer transaction. */ 278 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 279 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); 280 struct reiserfs_transaction_handle th; 281 err = journal_begin(&th, inode->i_sb, blocks); 282 if (!err) { 283 int jerror; 284 mutex_lock_nested(&dir->d_parent->d_inode->i_mutex, 285 I_MUTEX_XATTR); 286 err = action(dir, data); 287 jerror = journal_end(&th, inode->i_sb, blocks); 288 mutex_unlock(&dir->d_parent->d_inode->i_mutex); 289 err = jerror ?: err; 290 } 291 } 292 out_dir: 293 dput(dir); 294 out: 295 /* -ENODATA isn't an error */ 296 if (err == -ENODATA) 297 err = 0; 298 return err; 299 } 300 301 static int delete_one_xattr(struct dentry *dentry, void *data) 302 { 303 struct inode *dir = dentry->d_parent->d_inode; 304 305 /* This is the xattr dir, handle specially. */ 306 if (S_ISDIR(dentry->d_inode->i_mode)) 307 return xattr_rmdir(dir, dentry); 308 309 return xattr_unlink(dir, dentry); 310 } 311 312 static int chown_one_xattr(struct dentry *dentry, void *data) 313 { 314 struct iattr *attrs = data; 315 return reiserfs_setattr(dentry, attrs); 316 } 317 318 /* No i_mutex, but the inode is unconnected. */ 319 int reiserfs_delete_xattrs(struct inode *inode) 320 { 321 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL); 322 if (err) 323 reiserfs_warning(inode->i_sb, "jdm-20004", 324 "Couldn't delete all xattrs (%d)\n", err); 325 return err; 326 } 327 328 /* inode->i_mutex: down */ 329 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 330 { 331 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs); 332 if (err) 333 reiserfs_warning(inode->i_sb, "jdm-20007", 334 "Couldn't chown all xattrs (%d)\n", err); 335 return err; 336 } 337 338 #ifdef CONFIG_REISERFS_FS_XATTR 339 /* Returns a dentry corresponding to a specific extended attribute file 340 * for the inode. If flags allow, the file is created. Otherwise, a 341 * valid or negative dentry, or an error is returned. */ 342 static struct dentry *xattr_lookup(struct inode *inode, const char *name, 343 int flags) 344 { 345 struct dentry *xadir, *xafile; 346 int err = 0; 347 348 xadir = open_xa_dir(inode, flags); 349 if (IS_ERR(xadir)) 350 return ERR_CAST(xadir); 351 352 xafile = lookup_one_len(name, xadir, strlen(name)); 353 if (IS_ERR(xafile)) { 354 err = PTR_ERR(xafile); 355 goto out; 356 } 357 358 if (xafile->d_inode && (flags & XATTR_CREATE)) 359 err = -EEXIST; 360 361 if (!xafile->d_inode) { 362 err = -ENODATA; 363 if (xattr_may_create(flags)) { 364 mutex_lock_nested(&xadir->d_inode->i_mutex, 365 I_MUTEX_XATTR); 366 err = xattr_create(xadir->d_inode, xafile, 367 0700|S_IFREG); 368 mutex_unlock(&xadir->d_inode->i_mutex); 369 } 370 } 371 372 if (err) 373 dput(xafile); 374 out: 375 dput(xadir); 376 if (err) 377 return ERR_PTR(err); 378 return xafile; 379 } 380 381 /* Internal operations on file data */ 382 static inline void reiserfs_put_page(struct page *page) 383 { 384 kunmap(page); 385 page_cache_release(page); 386 } 387 388 static struct page *reiserfs_get_page(struct inode *dir, size_t n) 389 { 390 struct address_space *mapping = dir->i_mapping; 391 struct page *page; 392 /* We can deadlock if we try to free dentries, 393 and an unlink/rmdir has just occured - GFP_NOFS avoids this */ 394 mapping_set_gfp_mask(mapping, GFP_NOFS); 395 page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); 396 if (!IS_ERR(page)) { 397 kmap(page); 398 if (PageError(page)) 399 goto fail; 400 } 401 return page; 402 403 fail: 404 reiserfs_put_page(page); 405 return ERR_PTR(-EIO); 406 } 407 408 static inline __u32 xattr_hash(const char *msg, int len) 409 { 410 return csum_partial(msg, len, 0); 411 } 412 413 int reiserfs_commit_write(struct file *f, struct page *page, 414 unsigned from, unsigned to); 415 int reiserfs_prepare_write(struct file *f, struct page *page, 416 unsigned from, unsigned to); 417 418 static void update_ctime(struct inode *inode) 419 { 420 struct timespec now = current_fs_time(inode->i_sb); 421 if (hlist_unhashed(&inode->i_hash) || !inode->i_nlink || 422 timespec_equal(&inode->i_ctime, &now)) 423 return; 424 425 inode->i_ctime = CURRENT_TIME_SEC; 426 mark_inode_dirty(inode); 427 } 428 429 static int lookup_and_delete_xattr(struct inode *inode, const char *name) 430 { 431 int err = 0; 432 struct dentry *dentry, *xadir; 433 434 xadir = open_xa_dir(inode, XATTR_REPLACE); 435 if (IS_ERR(xadir)) 436 return PTR_ERR(xadir); 437 438 dentry = lookup_one_len(name, xadir, strlen(name)); 439 if (IS_ERR(dentry)) { 440 err = PTR_ERR(dentry); 441 goto out_dput; 442 } 443 444 if (dentry->d_inode) { 445 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 446 err = xattr_unlink(xadir->d_inode, dentry); 447 mutex_unlock(&xadir->d_inode->i_mutex); 448 update_ctime(inode); 449 } 450 451 dput(dentry); 452 out_dput: 453 dput(xadir); 454 return err; 455 } 456 457 458 /* Generic extended attribute operations that can be used by xa plugins */ 459 460 /* 461 * inode->i_mutex: down 462 */ 463 int 464 reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th, 465 struct inode *inode, const char *name, 466 const void *buffer, size_t buffer_size, int flags) 467 { 468 int err = 0; 469 struct dentry *dentry; 470 struct page *page; 471 char *data; 472 size_t file_pos = 0; 473 size_t buffer_pos = 0; 474 size_t new_size; 475 __u32 xahash = 0; 476 477 if (get_inode_sd_version(inode) == STAT_DATA_V1) 478 return -EOPNOTSUPP; 479 480 if (!buffer) 481 return lookup_and_delete_xattr(inode, name); 482 483 dentry = xattr_lookup(inode, name, flags); 484 if (IS_ERR(dentry)) 485 return PTR_ERR(dentry); 486 487 down_write(&REISERFS_I(inode)->i_xattr_sem); 488 489 xahash = xattr_hash(buffer, buffer_size); 490 while (buffer_pos < buffer_size || buffer_pos == 0) { 491 size_t chunk; 492 size_t skip = 0; 493 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 494 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 495 chunk = PAGE_CACHE_SIZE; 496 else 497 chunk = buffer_size - buffer_pos; 498 499 page = reiserfs_get_page(dentry->d_inode, file_pos); 500 if (IS_ERR(page)) { 501 err = PTR_ERR(page); 502 goto out_unlock; 503 } 504 505 lock_page(page); 506 data = page_address(page); 507 508 if (file_pos == 0) { 509 struct reiserfs_xattr_header *rxh; 510 skip = file_pos = sizeof(struct reiserfs_xattr_header); 511 if (chunk + skip > PAGE_CACHE_SIZE) 512 chunk = PAGE_CACHE_SIZE - skip; 513 rxh = (struct reiserfs_xattr_header *)data; 514 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 515 rxh->h_hash = cpu_to_le32(xahash); 516 } 517 518 err = reiserfs_prepare_write(NULL, page, page_offset, 519 page_offset + chunk + skip); 520 if (!err) { 521 if (buffer) 522 memcpy(data + skip, buffer + buffer_pos, chunk); 523 err = reiserfs_commit_write(NULL, page, page_offset, 524 page_offset + chunk + 525 skip); 526 } 527 unlock_page(page); 528 reiserfs_put_page(page); 529 buffer_pos += chunk; 530 file_pos += chunk; 531 skip = 0; 532 if (err || buffer_size == 0 || !buffer) 533 break; 534 } 535 536 new_size = buffer_size + sizeof(struct reiserfs_xattr_header); 537 if (!err && new_size < i_size_read(dentry->d_inode)) { 538 struct iattr newattrs = { 539 .ia_ctime = current_fs_time(inode->i_sb), 540 .ia_size = buffer_size, 541 .ia_valid = ATTR_SIZE | ATTR_CTIME, 542 }; 543 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 544 down_write(&dentry->d_inode->i_alloc_sem); 545 err = reiserfs_setattr(dentry, &newattrs); 546 up_write(&dentry->d_inode->i_alloc_sem); 547 mutex_unlock(&dentry->d_inode->i_mutex); 548 } else 549 update_ctime(inode); 550 out_unlock: 551 up_write(&REISERFS_I(inode)->i_xattr_sem); 552 dput(dentry); 553 return err; 554 } 555 556 /* We need to start a transaction to maintain lock ordering */ 557 int reiserfs_xattr_set(struct inode *inode, const char *name, 558 const void *buffer, size_t buffer_size, int flags) 559 { 560 561 struct reiserfs_transaction_handle th; 562 int error, error2; 563 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); 564 565 if (!(flags & XATTR_REPLACE)) 566 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); 567 568 reiserfs_write_lock(inode->i_sb); 569 error = journal_begin(&th, inode->i_sb, jbegin_count); 570 if (error) { 571 reiserfs_write_unlock(inode->i_sb); 572 return error; 573 } 574 575 error = reiserfs_xattr_set_handle(&th, inode, name, 576 buffer, buffer_size, flags); 577 578 error2 = journal_end(&th, inode->i_sb, jbegin_count); 579 if (error == 0) 580 error = error2; 581 reiserfs_write_unlock(inode->i_sb); 582 583 return error; 584 } 585 586 /* 587 * inode->i_mutex: down 588 */ 589 int 590 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, 591 size_t buffer_size) 592 { 593 ssize_t err = 0; 594 struct dentry *dentry; 595 size_t isize; 596 size_t file_pos = 0; 597 size_t buffer_pos = 0; 598 struct page *page; 599 __u32 hash = 0; 600 601 if (name == NULL) 602 return -EINVAL; 603 604 /* We can't have xattrs attached to v1 items since they don't have 605 * generation numbers */ 606 if (get_inode_sd_version(inode) == STAT_DATA_V1) 607 return -EOPNOTSUPP; 608 609 dentry = xattr_lookup(inode, name, XATTR_REPLACE); 610 if (IS_ERR(dentry)) { 611 err = PTR_ERR(dentry); 612 goto out; 613 } 614 615 down_read(&REISERFS_I(inode)->i_xattr_sem); 616 617 isize = i_size_read(dentry->d_inode); 618 619 /* Just return the size needed */ 620 if (buffer == NULL) { 621 err = isize - sizeof(struct reiserfs_xattr_header); 622 goto out_unlock; 623 } 624 625 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 626 err = -ERANGE; 627 goto out_unlock; 628 } 629 630 while (file_pos < isize) { 631 size_t chunk; 632 char *data; 633 size_t skip = 0; 634 if (isize - file_pos > PAGE_CACHE_SIZE) 635 chunk = PAGE_CACHE_SIZE; 636 else 637 chunk = isize - file_pos; 638 639 page = reiserfs_get_page(dentry->d_inode, file_pos); 640 if (IS_ERR(page)) { 641 err = PTR_ERR(page); 642 goto out_unlock; 643 } 644 645 lock_page(page); 646 data = page_address(page); 647 if (file_pos == 0) { 648 struct reiserfs_xattr_header *rxh = 649 (struct reiserfs_xattr_header *)data; 650 skip = file_pos = sizeof(struct reiserfs_xattr_header); 651 chunk -= skip; 652 /* Magic doesn't match up.. */ 653 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 654 unlock_page(page); 655 reiserfs_put_page(page); 656 reiserfs_warning(inode->i_sb, "jdm-20001", 657 "Invalid magic for xattr (%s) " 658 "associated with %k", name, 659 INODE_PKEY(inode)); 660 err = -EIO; 661 goto out_unlock; 662 } 663 hash = le32_to_cpu(rxh->h_hash); 664 } 665 memcpy(buffer + buffer_pos, data + skip, chunk); 666 unlock_page(page); 667 reiserfs_put_page(page); 668 file_pos += chunk; 669 buffer_pos += chunk; 670 skip = 0; 671 } 672 err = isize - sizeof(struct reiserfs_xattr_header); 673 674 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 675 hash) { 676 reiserfs_warning(inode->i_sb, "jdm-20002", 677 "Invalid hash for xattr (%s) associated " 678 "with %k", name, INODE_PKEY(inode)); 679 err = -EIO; 680 } 681 682 out_unlock: 683 up_read(&REISERFS_I(inode)->i_xattr_sem); 684 dput(dentry); 685 686 out: 687 return err; 688 } 689 690 /* Actual operations that are exported to VFS-land */ 691 struct xattr_handler *reiserfs_xattr_handlers[] = { 692 &reiserfs_xattr_user_handler, 693 &reiserfs_xattr_trusted_handler, 694 #ifdef CONFIG_REISERFS_FS_SECURITY 695 &reiserfs_xattr_security_handler, 696 #endif 697 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 698 &reiserfs_posix_acl_access_handler, 699 &reiserfs_posix_acl_default_handler, 700 #endif 701 NULL 702 }; 703 704 /* 705 * In order to implement different sets of xattr operations for each xattr 706 * prefix with the generic xattr API, a filesystem should create a 707 * null-terminated array of struct xattr_handler (one for each prefix) and 708 * hang a pointer to it off of the s_xattr field of the superblock. 709 * 710 * The generic_fooxattr() functions will use this list to dispatch xattr 711 * operations to the correct xattr_handler. 712 */ 713 #define for_each_xattr_handler(handlers, handler) \ 714 for ((handler) = *(handlers)++; \ 715 (handler) != NULL; \ 716 (handler) = *(handlers)++) 717 718 /* This is the implementation for the xattr plugin infrastructure */ 719 static inline struct xattr_handler * 720 find_xattr_handler_prefix(struct xattr_handler **handlers, 721 const char *name) 722 { 723 struct xattr_handler *xah; 724 725 if (!handlers) 726 return NULL; 727 728 for_each_xattr_handler(handlers, xah) { 729 if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0) 730 break; 731 } 732 733 return xah; 734 } 735 736 737 /* 738 * Inode operation getxattr() 739 */ 740 ssize_t 741 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 742 size_t size) 743 { 744 struct inode *inode = dentry->d_inode; 745 struct xattr_handler *handler; 746 747 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 748 749 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 750 return -EOPNOTSUPP; 751 752 return handler->get(inode, name, buffer, size); 753 } 754 755 /* 756 * Inode operation setxattr() 757 * 758 * dentry->d_inode->i_mutex down 759 */ 760 int 761 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 762 size_t size, int flags) 763 { 764 struct inode *inode = dentry->d_inode; 765 struct xattr_handler *handler; 766 767 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 768 769 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 770 return -EOPNOTSUPP; 771 772 return handler->set(inode, name, value, size, flags); 773 } 774 775 /* 776 * Inode operation removexattr() 777 * 778 * dentry->d_inode->i_mutex down 779 */ 780 int reiserfs_removexattr(struct dentry *dentry, const char *name) 781 { 782 struct inode *inode = dentry->d_inode; 783 struct xattr_handler *handler; 784 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 785 786 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 787 return -EOPNOTSUPP; 788 789 return handler->set(inode, name, NULL, 0, XATTR_REPLACE); 790 } 791 792 struct listxattr_buf { 793 size_t size; 794 size_t pos; 795 char *buf; 796 struct inode *inode; 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 struct xattr_handler *handler; 807 handler = find_xattr_handler_prefix(b->inode->i_sb->s_xattr, 808 name); 809 if (!handler) /* Unsupported xattr name */ 810 return 0; 811 if (b->buf) { 812 size = handler->list(b->inode, b->buf + b->pos, 813 b->size, name, namelen); 814 if (size > b->size) 815 return -ERANGE; 816 } else { 817 size = handler->list(b->inode, NULL, 0, name, namelen); 818 } 819 820 b->pos += size; 821 } 822 return 0; 823 } 824 825 /* 826 * Inode operation listxattr() 827 * 828 * We totally ignore the generic listxattr here because it would be stupid 829 * not to. Since the xattrs are organized in a directory, we can just 830 * readdir to find them. 831 */ 832 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 833 { 834 struct dentry *dir; 835 int err = 0; 836 loff_t pos = 0; 837 struct listxattr_buf buf = { 838 .inode = dentry->d_inode, 839 .buf = buffer, 840 .size = buffer ? size : 0, 841 }; 842 843 if (!dentry->d_inode) 844 return -EINVAL; 845 846 if (!reiserfs_xattrs(dentry->d_sb) || 847 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 848 return -EOPNOTSUPP; 849 850 dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); 851 if (IS_ERR(dir)) { 852 err = PTR_ERR(dir); 853 if (err == -ENODATA) 854 err = 0; /* Not an error if there aren't any xattrs */ 855 goto out; 856 } 857 858 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 859 err = reiserfs_readdir_dentry(dir, &buf, listxattr_filler, &pos); 860 mutex_unlock(&dir->d_inode->i_mutex); 861 862 if (!err) 863 err = buf.pos; 864 865 dput(dir); 866 out: 867 return err; 868 } 869 870 static int reiserfs_check_acl(struct inode *inode, int mask) 871 { 872 struct posix_acl *acl; 873 int error = -EAGAIN; /* do regular unix permission checks by default */ 874 875 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 876 877 if (acl) { 878 if (!IS_ERR(acl)) { 879 error = posix_acl_permission(inode, acl, mask); 880 posix_acl_release(acl); 881 } else if (PTR_ERR(acl) != -ENODATA) 882 error = PTR_ERR(acl); 883 } 884 885 return error; 886 } 887 888 int reiserfs_permission(struct inode *inode, int mask) 889 { 890 /* 891 * We don't do permission checks on the internal objects. 892 * Permissions are determined by the "owning" object. 893 */ 894 if (IS_PRIVATE(inode)) 895 return 0; 896 /* 897 * Stat data v1 doesn't support ACLs. 898 */ 899 if (get_inode_sd_version(inode) == STAT_DATA_V1) 900 return generic_permission(inode, mask, NULL); 901 else 902 return generic_permission(inode, mask, reiserfs_check_acl); 903 } 904 905 static int create_privroot(struct dentry *dentry) 906 { 907 int err; 908 struct inode *inode = dentry->d_parent->d_inode; 909 mutex_lock_nested(&inode->i_mutex, I_MUTEX_XATTR); 910 err = xattr_mkdir(inode, dentry, 0700); 911 mutex_unlock(&inode->i_mutex); 912 if (err) { 913 dput(dentry); 914 dentry = NULL; 915 } 916 917 if (dentry && dentry->d_inode) 918 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 919 "storage.\n", PRIVROOT_NAME); 920 921 return err; 922 } 923 924 static int xattr_mount_check(struct super_block *s) 925 { 926 /* We need generation numbers to ensure that the oid mapping is correct 927 * v3.5 filesystems don't have them. */ 928 if (old_format_only(s)) { 929 if (reiserfs_xattrs_optional(s)) { 930 /* Old format filesystem, but optional xattrs have 931 * been enabled. Error out. */ 932 reiserfs_warning(s, "jdm-2005", 933 "xattrs/ACLs not supported " 934 "on pre-v3.6 format filesystems. " 935 "Failing mount."); 936 return -EOPNOTSUPP; 937 } 938 } 939 940 return 0; 941 } 942 943 #else 944 int __init reiserfs_xattr_register_handlers(void) { return 0; } 945 void reiserfs_xattr_unregister_handlers(void) {} 946 #endif 947 948 /* This will catch lookups from the fs root to .reiserfs_priv */ 949 static int 950 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 951 { 952 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 953 if (name->len == priv_root->d_name.len && 954 name->hash == priv_root->d_name.hash && 955 !memcmp(name->name, priv_root->d_name.name, name->len)) { 956 return -ENOENT; 957 } else if (q1->len == name->len && 958 !memcmp(q1->name, name->name, name->len)) 959 return 0; 960 return 1; 961 } 962 963 static const struct dentry_operations xattr_lookup_poison_ops = { 964 .d_compare = xattr_lookup_poison, 965 }; 966 967 /* We need to take a copy of the mount flags since things like 968 * MS_RDONLY don't get set until *after* we're called. 969 * mount_flags != mount_options */ 970 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 971 { 972 int err = 0; 973 974 #ifdef CONFIG_REISERFS_FS_XATTR 975 err = xattr_mount_check(s); 976 if (err) 977 goto error; 978 #endif 979 980 /* If we don't have the privroot located yet - go find it */ 981 if (!REISERFS_SB(s)->priv_root) { 982 struct dentry *dentry; 983 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 984 strlen(PRIVROOT_NAME)); 985 if (!IS_ERR(dentry)) { 986 #ifdef CONFIG_REISERFS_FS_XATTR 987 if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) 988 err = create_privroot(dentry); 989 #endif 990 if (!dentry->d_inode) { 991 dput(dentry); 992 dentry = NULL; 993 } 994 } else 995 err = PTR_ERR(dentry); 996 997 if (!err && dentry) { 998 s->s_root->d_op = &xattr_lookup_poison_ops; 999 dentry->d_inode->i_flags |= S_PRIVATE; 1000 REISERFS_SB(s)->priv_root = dentry; 1001 #ifdef CONFIG_REISERFS_FS_XATTR 1002 /* xattrs are unavailable */ 1003 } else if (!(mount_flags & MS_RDONLY)) { 1004 /* If we're read-only it just means that the dir 1005 * hasn't been created. Not an error -- just no 1006 * xattrs on the fs. We'll check again if we 1007 * go read-write */ 1008 reiserfs_warning(s, "jdm-20006", 1009 "xattrs/ACLs enabled and couldn't " 1010 "find/create .reiserfs_priv. " 1011 "Failing mount."); 1012 err = -EOPNOTSUPP; 1013 #endif 1014 } 1015 } 1016 1017 #ifdef CONFIG_REISERFS_FS_XATTR 1018 if (!err) 1019 s->s_xattr = reiserfs_xattr_handlers; 1020 1021 error: 1022 if (err) { 1023 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1024 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1025 } 1026 #endif 1027 1028 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1029 s->s_flags = s->s_flags & ~MS_POSIXACL; 1030 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 1031 if (reiserfs_posixacl(s)) 1032 s->s_flags |= MS_POSIXACL; 1033 #endif 1034 1035 return err; 1036 } 1037