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 static int xattr_create(struct inode *dir, struct dentry *dentry, int mode) 61 { 62 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 63 DQUOT_INIT(dir); 64 return dir->i_op->create(dir, dentry, mode, NULL); 65 } 66 67 static int xattr_mkdir(struct inode *dir, struct dentry *dentry, int mode) 68 { 69 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 70 DQUOT_INIT(dir); 71 return dir->i_op->mkdir(dir, dentry, mode); 72 } 73 74 /* We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr 75 * mutation ops aren't called during rename or splace, which are the 76 * only other users of I_MUTEX_CHILD. It violates the ordering, but that's 77 * better than allocating another subclass just for this code. */ 78 static int xattr_unlink(struct inode *dir, struct dentry *dentry) 79 { 80 int error; 81 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 82 DQUOT_INIT(dir); 83 84 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); 85 error = dir->i_op->unlink(dir, dentry); 86 mutex_unlock(&dentry->d_inode->i_mutex); 87 88 if (!error) 89 d_delete(dentry); 90 return error; 91 } 92 93 static int xattr_rmdir(struct inode *dir, struct dentry *dentry) 94 { 95 int error; 96 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 97 DQUOT_INIT(dir); 98 99 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); 100 dentry_unhash(dentry); 101 error = dir->i_op->rmdir(dir, dentry); 102 if (!error) 103 dentry->d_inode->i_flags |= S_DEAD; 104 mutex_unlock(&dentry->d_inode->i_mutex); 105 if (!error) 106 d_delete(dentry); 107 dput(dentry); 108 109 return error; 110 } 111 112 #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE) 113 114 /* Returns and possibly creates the xattr dir. */ 115 static struct dentry *lookup_or_create_dir(struct dentry *parent, 116 const char *name, int flags) 117 { 118 struct dentry *dentry; 119 BUG_ON(!parent); 120 121 dentry = lookup_one_len(name, parent, strlen(name)); 122 if (IS_ERR(dentry)) 123 return dentry; 124 else if (!dentry->d_inode) { 125 int err = -ENODATA; 126 127 if (xattr_may_create(flags)) { 128 mutex_lock_nested(&parent->d_inode->i_mutex, 129 I_MUTEX_XATTR); 130 err = xattr_mkdir(parent->d_inode, dentry, 0700); 131 mutex_unlock(&parent->d_inode->i_mutex); 132 } 133 134 if (err) { 135 dput(dentry); 136 dentry = ERR_PTR(err); 137 } 138 } 139 140 return dentry; 141 } 142 143 static struct dentry *open_xa_root(struct super_block *sb, int flags) 144 { 145 struct dentry *privroot = REISERFS_SB(sb)->priv_root; 146 if (!privroot) 147 return ERR_PTR(-ENODATA); 148 return lookup_or_create_dir(privroot, XAROOT_NAME, flags); 149 } 150 151 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 152 { 153 struct dentry *xaroot, *xadir; 154 char namebuf[17]; 155 156 xaroot = open_xa_root(inode->i_sb, flags); 157 if (IS_ERR(xaroot)) 158 return xaroot; 159 160 snprintf(namebuf, sizeof(namebuf), "%X.%X", 161 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 162 inode->i_generation); 163 164 xadir = lookup_or_create_dir(xaroot, namebuf, flags); 165 dput(xaroot); 166 return xadir; 167 168 } 169 170 /* The following are side effects of other operations that aren't explicitly 171 * modifying extended attributes. This includes operations such as permissions 172 * or ownership changes, object deletions, etc. */ 173 struct reiserfs_dentry_buf { 174 struct dentry *xadir; 175 int count; 176 struct dentry *dentries[8]; 177 }; 178 179 static int 180 fill_with_dentries(void *buf, const char *name, int namelen, loff_t offset, 181 u64 ino, unsigned int d_type) 182 { 183 struct reiserfs_dentry_buf *dbuf = buf; 184 struct dentry *dentry; 185 186 if (dbuf->count == ARRAY_SIZE(dbuf->dentries)) 187 return -ENOSPC; 188 189 if (name[0] == '.' && (name[1] == '\0' || 190 (name[1] == '.' && name[2] == '\0'))) 191 return 0; 192 193 dentry = lookup_one_len(name, dbuf->xadir, namelen); 194 if (IS_ERR(dentry)) { 195 return PTR_ERR(dentry); 196 } else if (!dentry->d_inode) { 197 /* A directory entry exists, but no file? */ 198 reiserfs_error(dentry->d_sb, "xattr-20003", 199 "Corrupted directory: xattr %s listed but " 200 "not found for file %s.\n", 201 dentry->d_name.name, dbuf->xadir->d_name.name); 202 dput(dentry); 203 return -EIO; 204 } 205 206 dbuf->dentries[dbuf->count++] = dentry; 207 return 0; 208 } 209 210 static void 211 cleanup_dentry_buf(struct reiserfs_dentry_buf *buf) 212 { 213 int i; 214 for (i = 0; i < buf->count; i++) 215 if (buf->dentries[i]) 216 dput(buf->dentries[i]); 217 } 218 219 static int reiserfs_for_each_xattr(struct inode *inode, 220 int (*action)(struct dentry *, void *), 221 void *data) 222 { 223 struct dentry *dir; 224 int i, err = 0; 225 loff_t pos = 0; 226 struct reiserfs_dentry_buf buf = { 227 .count = 0, 228 }; 229 230 /* Skip out, an xattr has no xattrs associated with it */ 231 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 232 return 0; 233 234 dir = open_xa_dir(inode, XATTR_REPLACE); 235 if (IS_ERR(dir)) { 236 err = PTR_ERR(dir); 237 goto out; 238 } else if (!dir->d_inode) { 239 err = 0; 240 goto out_dir; 241 } 242 243 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 244 buf.xadir = dir; 245 err = reiserfs_readdir_dentry(dir, &buf, fill_with_dentries, &pos); 246 while ((err == 0 || err == -ENOSPC) && buf.count) { 247 err = 0; 248 249 for (i = 0; i < buf.count && buf.dentries[i]; i++) { 250 int lerr = 0; 251 struct dentry *dentry = buf.dentries[i]; 252 253 if (err == 0 && !S_ISDIR(dentry->d_inode->i_mode)) 254 lerr = action(dentry, data); 255 256 dput(dentry); 257 buf.dentries[i] = NULL; 258 err = lerr ?: err; 259 } 260 buf.count = 0; 261 if (!err) 262 err = reiserfs_readdir_dentry(dir, &buf, 263 fill_with_dentries, &pos); 264 } 265 mutex_unlock(&dir->d_inode->i_mutex); 266 267 /* Clean up after a failed readdir */ 268 cleanup_dentry_buf(&buf); 269 270 if (!err) { 271 /* We start a transaction here to avoid a ABBA situation 272 * between the xattr root's i_mutex and the journal lock. 273 * This doesn't incur much additional overhead since the 274 * new transaction will just nest inside the 275 * outer transaction. */ 276 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 277 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); 278 struct reiserfs_transaction_handle th; 279 err = journal_begin(&th, inode->i_sb, blocks); 280 if (!err) { 281 int jerror; 282 mutex_lock_nested(&dir->d_parent->d_inode->i_mutex, 283 I_MUTEX_XATTR); 284 err = action(dir, data); 285 jerror = journal_end(&th, inode->i_sb, blocks); 286 mutex_unlock(&dir->d_parent->d_inode->i_mutex); 287 err = jerror ?: err; 288 } 289 } 290 out_dir: 291 dput(dir); 292 out: 293 /* -ENODATA isn't an error */ 294 if (err == -ENODATA) 295 err = 0; 296 return err; 297 } 298 299 static int delete_one_xattr(struct dentry *dentry, void *data) 300 { 301 struct inode *dir = dentry->d_parent->d_inode; 302 303 /* This is the xattr dir, handle specially. */ 304 if (S_ISDIR(dentry->d_inode->i_mode)) 305 return xattr_rmdir(dir, dentry); 306 307 return xattr_unlink(dir, dentry); 308 } 309 310 static int chown_one_xattr(struct dentry *dentry, void *data) 311 { 312 struct iattr *attrs = data; 313 return reiserfs_setattr(dentry, attrs); 314 } 315 316 /* No i_mutex, but the inode is unconnected. */ 317 int reiserfs_delete_xattrs(struct inode *inode) 318 { 319 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL); 320 if (err) 321 reiserfs_warning(inode->i_sb, "jdm-20004", 322 "Couldn't delete all xattrs (%d)\n", err); 323 return err; 324 } 325 326 /* inode->i_mutex: down */ 327 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 328 { 329 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs); 330 if (err) 331 reiserfs_warning(inode->i_sb, "jdm-20007", 332 "Couldn't chown all xattrs (%d)\n", err); 333 return err; 334 } 335 336 #ifdef CONFIG_REISERFS_FS_XATTR 337 /* Returns a dentry corresponding to a specific extended attribute file 338 * for the inode. If flags allow, the file is created. Otherwise, a 339 * valid or negative dentry, or an error is returned. */ 340 static struct dentry *xattr_lookup(struct inode *inode, const char *name, 341 int flags) 342 { 343 struct dentry *xadir, *xafile; 344 int err = 0; 345 346 xadir = open_xa_dir(inode, flags); 347 if (IS_ERR(xadir)) 348 return ERR_CAST(xadir); 349 350 xafile = lookup_one_len(name, xadir, strlen(name)); 351 if (IS_ERR(xafile)) { 352 err = PTR_ERR(xafile); 353 goto out; 354 } 355 356 if (xafile->d_inode && (flags & XATTR_CREATE)) 357 err = -EEXIST; 358 359 if (!xafile->d_inode) { 360 err = -ENODATA; 361 if (xattr_may_create(flags)) { 362 mutex_lock_nested(&xadir->d_inode->i_mutex, 363 I_MUTEX_XATTR); 364 err = xattr_create(xadir->d_inode, xafile, 365 0700|S_IFREG); 366 mutex_unlock(&xadir->d_inode->i_mutex); 367 } 368 } 369 370 if (err) 371 dput(xafile); 372 out: 373 dput(xadir); 374 if (err) 375 return ERR_PTR(err); 376 return xafile; 377 } 378 379 /* Internal operations on file data */ 380 static inline void reiserfs_put_page(struct page *page) 381 { 382 kunmap(page); 383 page_cache_release(page); 384 } 385 386 static struct page *reiserfs_get_page(struct inode *dir, size_t n) 387 { 388 struct address_space *mapping = dir->i_mapping; 389 struct page *page; 390 /* We can deadlock if we try to free dentries, 391 and an unlink/rmdir has just occured - GFP_NOFS avoids this */ 392 mapping_set_gfp_mask(mapping, GFP_NOFS); 393 page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); 394 if (!IS_ERR(page)) { 395 kmap(page); 396 if (PageError(page)) 397 goto fail; 398 } 399 return page; 400 401 fail: 402 reiserfs_put_page(page); 403 return ERR_PTR(-EIO); 404 } 405 406 static inline __u32 xattr_hash(const char *msg, int len) 407 { 408 return csum_partial(msg, len, 0); 409 } 410 411 int reiserfs_commit_write(struct file *f, struct page *page, 412 unsigned from, unsigned to); 413 int reiserfs_prepare_write(struct file *f, struct page *page, 414 unsigned from, unsigned to); 415 416 static void update_ctime(struct inode *inode) 417 { 418 struct timespec now = current_fs_time(inode->i_sb); 419 if (hlist_unhashed(&inode->i_hash) || !inode->i_nlink || 420 timespec_equal(&inode->i_ctime, &now)) 421 return; 422 423 inode->i_ctime = CURRENT_TIME_SEC; 424 mark_inode_dirty(inode); 425 } 426 427 static int lookup_and_delete_xattr(struct inode *inode, const char *name) 428 { 429 int err = 0; 430 struct dentry *dentry, *xadir; 431 432 xadir = open_xa_dir(inode, XATTR_REPLACE); 433 if (IS_ERR(xadir)) 434 return PTR_ERR(xadir); 435 436 dentry = lookup_one_len(name, xadir, strlen(name)); 437 if (IS_ERR(dentry)) { 438 err = PTR_ERR(dentry); 439 goto out_dput; 440 } 441 442 if (dentry->d_inode) { 443 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 444 err = xattr_unlink(xadir->d_inode, dentry); 445 mutex_unlock(&xadir->d_inode->i_mutex); 446 update_ctime(inode); 447 } 448 449 dput(dentry); 450 out_dput: 451 dput(xadir); 452 return err; 453 } 454 455 456 /* Generic extended attribute operations that can be used by xa plugins */ 457 458 /* 459 * inode->i_mutex: down 460 */ 461 int 462 reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th, 463 struct inode *inode, const char *name, 464 const void *buffer, size_t buffer_size, int flags) 465 { 466 int err = 0; 467 struct dentry *dentry; 468 struct page *page; 469 char *data; 470 size_t file_pos = 0; 471 size_t buffer_pos = 0; 472 size_t new_size; 473 __u32 xahash = 0; 474 475 if (get_inode_sd_version(inode) == STAT_DATA_V1) 476 return -EOPNOTSUPP; 477 478 if (!buffer) 479 return lookup_and_delete_xattr(inode, name); 480 481 dentry = xattr_lookup(inode, name, flags); 482 if (IS_ERR(dentry)) 483 return PTR_ERR(dentry); 484 485 down_write(&REISERFS_I(inode)->i_xattr_sem); 486 487 xahash = xattr_hash(buffer, buffer_size); 488 while (buffer_pos < buffer_size || buffer_pos == 0) { 489 size_t chunk; 490 size_t skip = 0; 491 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 492 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 493 chunk = PAGE_CACHE_SIZE; 494 else 495 chunk = buffer_size - buffer_pos; 496 497 page = reiserfs_get_page(dentry->d_inode, file_pos); 498 if (IS_ERR(page)) { 499 err = PTR_ERR(page); 500 goto out_unlock; 501 } 502 503 lock_page(page); 504 data = page_address(page); 505 506 if (file_pos == 0) { 507 struct reiserfs_xattr_header *rxh; 508 skip = file_pos = sizeof(struct reiserfs_xattr_header); 509 if (chunk + skip > PAGE_CACHE_SIZE) 510 chunk = PAGE_CACHE_SIZE - skip; 511 rxh = (struct reiserfs_xattr_header *)data; 512 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 513 rxh->h_hash = cpu_to_le32(xahash); 514 } 515 516 err = reiserfs_prepare_write(NULL, page, page_offset, 517 page_offset + chunk + skip); 518 if (!err) { 519 if (buffer) 520 memcpy(data + skip, buffer + buffer_pos, chunk); 521 err = reiserfs_commit_write(NULL, page, page_offset, 522 page_offset + chunk + 523 skip); 524 } 525 unlock_page(page); 526 reiserfs_put_page(page); 527 buffer_pos += chunk; 528 file_pos += chunk; 529 skip = 0; 530 if (err || buffer_size == 0 || !buffer) 531 break; 532 } 533 534 new_size = buffer_size + sizeof(struct reiserfs_xattr_header); 535 if (!err && new_size < i_size_read(dentry->d_inode)) { 536 struct iattr newattrs = { 537 .ia_ctime = current_fs_time(inode->i_sb), 538 .ia_size = buffer_size, 539 .ia_valid = ATTR_SIZE | ATTR_CTIME, 540 }; 541 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 542 down_write(&dentry->d_inode->i_alloc_sem); 543 err = reiserfs_setattr(dentry, &newattrs); 544 up_write(&dentry->d_inode->i_alloc_sem); 545 mutex_unlock(&dentry->d_inode->i_mutex); 546 } else 547 update_ctime(inode); 548 out_unlock: 549 up_write(&REISERFS_I(inode)->i_xattr_sem); 550 dput(dentry); 551 return err; 552 } 553 554 /* We need to start a transaction to maintain lock ordering */ 555 int reiserfs_xattr_set(struct inode *inode, const char *name, 556 const void *buffer, size_t buffer_size, int flags) 557 { 558 559 struct reiserfs_transaction_handle th; 560 int error, error2; 561 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); 562 563 if (!(flags & XATTR_REPLACE)) 564 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); 565 566 reiserfs_write_lock(inode->i_sb); 567 error = journal_begin(&th, inode->i_sb, jbegin_count); 568 if (error) { 569 reiserfs_write_unlock(inode->i_sb); 570 return error; 571 } 572 573 error = reiserfs_xattr_set_handle(&th, inode, name, 574 buffer, buffer_size, flags); 575 576 error2 = journal_end(&th, inode->i_sb, jbegin_count); 577 if (error == 0) 578 error = error2; 579 reiserfs_write_unlock(inode->i_sb); 580 581 return error; 582 } 583 584 /* 585 * inode->i_mutex: down 586 */ 587 int 588 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, 589 size_t buffer_size) 590 { 591 ssize_t err = 0; 592 struct dentry *dentry; 593 size_t isize; 594 size_t file_pos = 0; 595 size_t buffer_pos = 0; 596 struct page *page; 597 __u32 hash = 0; 598 599 if (name == NULL) 600 return -EINVAL; 601 602 /* We can't have xattrs attached to v1 items since they don't have 603 * generation numbers */ 604 if (get_inode_sd_version(inode) == STAT_DATA_V1) 605 return -EOPNOTSUPP; 606 607 dentry = xattr_lookup(inode, name, XATTR_REPLACE); 608 if (IS_ERR(dentry)) { 609 err = PTR_ERR(dentry); 610 goto out; 611 } 612 613 down_read(&REISERFS_I(inode)->i_xattr_sem); 614 615 isize = i_size_read(dentry->d_inode); 616 617 /* Just return the size needed */ 618 if (buffer == NULL) { 619 err = isize - sizeof(struct reiserfs_xattr_header); 620 goto out_unlock; 621 } 622 623 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 624 err = -ERANGE; 625 goto out_unlock; 626 } 627 628 while (file_pos < isize) { 629 size_t chunk; 630 char *data; 631 size_t skip = 0; 632 if (isize - file_pos > PAGE_CACHE_SIZE) 633 chunk = PAGE_CACHE_SIZE; 634 else 635 chunk = isize - file_pos; 636 637 page = reiserfs_get_page(dentry->d_inode, file_pos); 638 if (IS_ERR(page)) { 639 err = PTR_ERR(page); 640 goto out_unlock; 641 } 642 643 lock_page(page); 644 data = page_address(page); 645 if (file_pos == 0) { 646 struct reiserfs_xattr_header *rxh = 647 (struct reiserfs_xattr_header *)data; 648 skip = file_pos = sizeof(struct reiserfs_xattr_header); 649 chunk -= skip; 650 /* Magic doesn't match up.. */ 651 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 652 unlock_page(page); 653 reiserfs_put_page(page); 654 reiserfs_warning(inode->i_sb, "jdm-20001", 655 "Invalid magic for xattr (%s) " 656 "associated with %k", name, 657 INODE_PKEY(inode)); 658 err = -EIO; 659 goto out_unlock; 660 } 661 hash = le32_to_cpu(rxh->h_hash); 662 } 663 memcpy(buffer + buffer_pos, data + skip, chunk); 664 unlock_page(page); 665 reiserfs_put_page(page); 666 file_pos += chunk; 667 buffer_pos += chunk; 668 skip = 0; 669 } 670 err = isize - sizeof(struct reiserfs_xattr_header); 671 672 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 673 hash) { 674 reiserfs_warning(inode->i_sb, "jdm-20002", 675 "Invalid hash for xattr (%s) associated " 676 "with %k", name, INODE_PKEY(inode)); 677 err = -EIO; 678 } 679 680 out_unlock: 681 up_read(&REISERFS_I(inode)->i_xattr_sem); 682 dput(dentry); 683 684 out: 685 return err; 686 } 687 688 /* Actual operations that are exported to VFS-land */ 689 struct xattr_handler *reiserfs_xattr_handlers[] = { 690 &reiserfs_xattr_user_handler, 691 &reiserfs_xattr_trusted_handler, 692 #ifdef CONFIG_REISERFS_FS_SECURITY 693 &reiserfs_xattr_security_handler, 694 #endif 695 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 696 &reiserfs_posix_acl_access_handler, 697 &reiserfs_posix_acl_default_handler, 698 #endif 699 NULL 700 }; 701 702 /* 703 * In order to implement different sets of xattr operations for each xattr 704 * prefix with the generic xattr API, a filesystem should create a 705 * null-terminated array of struct xattr_handler (one for each prefix) and 706 * hang a pointer to it off of the s_xattr field of the superblock. 707 * 708 * The generic_fooxattr() functions will use this list to dispatch xattr 709 * operations to the correct xattr_handler. 710 */ 711 #define for_each_xattr_handler(handlers, handler) \ 712 for ((handler) = *(handlers)++; \ 713 (handler) != NULL; \ 714 (handler) = *(handlers)++) 715 716 /* This is the implementation for the xattr plugin infrastructure */ 717 static inline struct xattr_handler * 718 find_xattr_handler_prefix(struct xattr_handler **handlers, 719 const char *name) 720 { 721 struct xattr_handler *xah; 722 723 if (!handlers) 724 return NULL; 725 726 for_each_xattr_handler(handlers, xah) { 727 if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0) 728 break; 729 } 730 731 return xah; 732 } 733 734 735 /* 736 * Inode operation getxattr() 737 */ 738 ssize_t 739 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 740 size_t size) 741 { 742 struct inode *inode = dentry->d_inode; 743 struct xattr_handler *handler; 744 745 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 746 747 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 748 return -EOPNOTSUPP; 749 750 return handler->get(inode, name, buffer, size); 751 } 752 753 /* 754 * Inode operation setxattr() 755 * 756 * dentry->d_inode->i_mutex down 757 */ 758 int 759 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 760 size_t size, int flags) 761 { 762 struct inode *inode = dentry->d_inode; 763 struct xattr_handler *handler; 764 765 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 766 767 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 768 return -EOPNOTSUPP; 769 770 return handler->set(inode, name, value, size, flags); 771 } 772 773 /* 774 * Inode operation removexattr() 775 * 776 * dentry->d_inode->i_mutex down 777 */ 778 int reiserfs_removexattr(struct dentry *dentry, const char *name) 779 { 780 struct inode *inode = dentry->d_inode; 781 struct xattr_handler *handler; 782 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 783 784 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 785 return -EOPNOTSUPP; 786 787 return handler->set(inode, name, NULL, 0, XATTR_REPLACE); 788 } 789 790 struct listxattr_buf { 791 size_t size; 792 size_t pos; 793 char *buf; 794 struct inode *inode; 795 }; 796 797 static int listxattr_filler(void *buf, const char *name, int namelen, 798 loff_t offset, u64 ino, unsigned int d_type) 799 { 800 struct listxattr_buf *b = (struct listxattr_buf *)buf; 801 size_t size; 802 if (name[0] != '.' || 803 (namelen != 1 && (name[1] != '.' || namelen != 2))) { 804 struct xattr_handler *handler; 805 handler = find_xattr_handler_prefix(b->inode->i_sb->s_xattr, 806 name); 807 if (!handler) /* Unsupported xattr name */ 808 return 0; 809 if (b->buf) { 810 size = handler->list(b->inode, b->buf + b->pos, 811 b->size, name, namelen); 812 if (size > b->size) 813 return -ERANGE; 814 } else { 815 size = handler->list(b->inode, NULL, 0, name, namelen); 816 } 817 818 b->pos += size; 819 } 820 return 0; 821 } 822 823 /* 824 * Inode operation listxattr() 825 * 826 * We totally ignore the generic listxattr here because it would be stupid 827 * not to. Since the xattrs are organized in a directory, we can just 828 * readdir to find them. 829 */ 830 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 831 { 832 struct dentry *dir; 833 int err = 0; 834 loff_t pos = 0; 835 struct listxattr_buf buf = { 836 .inode = dentry->d_inode, 837 .buf = buffer, 838 .size = buffer ? size : 0, 839 }; 840 841 if (!dentry->d_inode) 842 return -EINVAL; 843 844 if (!reiserfs_xattrs(dentry->d_sb) || 845 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 846 return -EOPNOTSUPP; 847 848 dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); 849 if (IS_ERR(dir)) { 850 err = PTR_ERR(dir); 851 if (err == -ENODATA) 852 err = 0; /* Not an error if there aren't any xattrs */ 853 goto out; 854 } 855 856 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 857 err = reiserfs_readdir_dentry(dir, &buf, listxattr_filler, &pos); 858 mutex_unlock(&dir->d_inode->i_mutex); 859 860 if (!err) 861 err = buf.pos; 862 863 dput(dir); 864 out: 865 return err; 866 } 867 868 static int reiserfs_check_acl(struct inode *inode, int mask) 869 { 870 struct posix_acl *acl; 871 int error = -EAGAIN; /* do regular unix permission checks by default */ 872 873 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 874 875 if (acl) { 876 if (!IS_ERR(acl)) { 877 error = posix_acl_permission(inode, acl, mask); 878 posix_acl_release(acl); 879 } else if (PTR_ERR(acl) != -ENODATA) 880 error = PTR_ERR(acl); 881 } 882 883 return error; 884 } 885 886 int reiserfs_permission(struct inode *inode, int mask) 887 { 888 /* 889 * We don't do permission checks on the internal objects. 890 * Permissions are determined by the "owning" object. 891 */ 892 if (IS_PRIVATE(inode)) 893 return 0; 894 /* 895 * Stat data v1 doesn't support ACLs. 896 */ 897 if (get_inode_sd_version(inode) == STAT_DATA_V1) 898 return generic_permission(inode, mask, NULL); 899 else 900 return generic_permission(inode, mask, reiserfs_check_acl); 901 } 902 903 static int create_privroot(struct dentry *dentry) 904 { 905 int err; 906 struct inode *inode = dentry->d_parent->d_inode; 907 mutex_lock_nested(&inode->i_mutex, I_MUTEX_XATTR); 908 err = xattr_mkdir(inode, dentry, 0700); 909 mutex_unlock(&inode->i_mutex); 910 if (err) { 911 dput(dentry); 912 dentry = NULL; 913 } 914 915 if (dentry && dentry->d_inode) 916 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 917 "storage.\n", PRIVROOT_NAME); 918 919 return err; 920 } 921 922 static int xattr_mount_check(struct super_block *s) 923 { 924 /* We need generation numbers to ensure that the oid mapping is correct 925 * v3.5 filesystems don't have them. */ 926 if (old_format_only(s)) { 927 if (reiserfs_xattrs_optional(s)) { 928 /* Old format filesystem, but optional xattrs have 929 * been enabled. Error out. */ 930 reiserfs_warning(s, "jdm-2005", 931 "xattrs/ACLs not supported " 932 "on pre-v3.6 format filesystems. " 933 "Failing mount."); 934 return -EOPNOTSUPP; 935 } 936 } 937 938 return 0; 939 } 940 941 #else 942 int __init reiserfs_xattr_register_handlers(void) { return 0; } 943 void reiserfs_xattr_unregister_handlers(void) {} 944 #endif 945 946 /* This will catch lookups from the fs root to .reiserfs_priv */ 947 static int 948 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 949 { 950 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 951 if (name->len == priv_root->d_name.len && 952 name->hash == priv_root->d_name.hash && 953 !memcmp(name->name, priv_root->d_name.name, name->len)) { 954 return -ENOENT; 955 } else if (q1->len == name->len && 956 !memcmp(q1->name, name->name, name->len)) 957 return 0; 958 return 1; 959 } 960 961 static struct dentry_operations xattr_lookup_poison_ops = { 962 .d_compare = xattr_lookup_poison, 963 }; 964 965 /* We need to take a copy of the mount flags since things like 966 * MS_RDONLY don't get set until *after* we're called. 967 * mount_flags != mount_options */ 968 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 969 { 970 int err = 0; 971 972 #ifdef CONFIG_REISERFS_FS_XATTR 973 err = xattr_mount_check(s); 974 if (err) 975 goto error; 976 #endif 977 978 /* If we don't have the privroot located yet - go find it */ 979 if (!REISERFS_SB(s)->priv_root) { 980 struct dentry *dentry; 981 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 982 strlen(PRIVROOT_NAME)); 983 if (!IS_ERR(dentry)) { 984 #ifdef CONFIG_REISERFS_FS_XATTR 985 if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) 986 err = create_privroot(dentry); 987 #endif 988 if (!dentry->d_inode) { 989 dput(dentry); 990 dentry = NULL; 991 } 992 } else 993 err = PTR_ERR(dentry); 994 995 if (!err && dentry) { 996 s->s_root->d_op = &xattr_lookup_poison_ops; 997 dentry->d_inode->i_flags |= S_PRIVATE; 998 REISERFS_SB(s)->priv_root = dentry; 999 #ifdef CONFIG_REISERFS_FS_XATTR 1000 /* xattrs are unavailable */ 1001 } else if (!(mount_flags & MS_RDONLY)) { 1002 /* If we're read-only it just means that the dir 1003 * hasn't been created. Not an error -- just no 1004 * xattrs on the fs. We'll check again if we 1005 * go read-write */ 1006 reiserfs_warning(s, "jdm-20006", 1007 "xattrs/ACLs enabled and couldn't " 1008 "find/create .reiserfs_priv. " 1009 "Failing mount."); 1010 err = -EOPNOTSUPP; 1011 #endif 1012 } 1013 } 1014 1015 #ifdef CONFIG_REISERFS_FS_XATTR 1016 if (!err) 1017 s->s_xattr = reiserfs_xattr_handlers; 1018 1019 error: 1020 if (err) { 1021 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1022 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1023 } 1024 #endif 1025 1026 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1027 s->s_flags = s->s_flags & ~MS_POSIXACL; 1028 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 1029 if (reiserfs_posixacl(s)) 1030 s->s_flags |= MS_POSIXACL; 1031 #endif 1032 1033 return err; 1034 } 1035