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 32 #include <linux/reiserfs_fs.h> 33 #include <linux/capability.h> 34 #include <linux/dcache.h> 35 #include <linux/namei.h> 36 #include <linux/errno.h> 37 #include <linux/fs.h> 38 #include <linux/file.h> 39 #include <linux/pagemap.h> 40 #include <linux/xattr.h> 41 #include <linux/reiserfs_xattr.h> 42 #include <linux/reiserfs_acl.h> 43 #include <asm/uaccess.h> 44 #include <net/checksum.h> 45 #include <linux/smp_lock.h> 46 #include <linux/stat.h> 47 #include <asm/semaphore.h> 48 49 #define FL_READONLY 128 50 #define FL_DIR_SEM_HELD 256 51 #define PRIVROOT_NAME ".reiserfs_priv" 52 #define XAROOT_NAME "xattrs" 53 54 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char 55 *prefix); 56 57 /* Returns the dentry referring to the root of the extended attribute 58 * directory tree. If it has already been retrieved, it is used. If it 59 * hasn't been created and the flags indicate creation is allowed, we 60 * attempt to create it. On error, we return a pointer-encoded error. 61 */ 62 static struct dentry *get_xa_root(struct super_block *sb, int flags) 63 { 64 struct dentry *privroot = dget(REISERFS_SB(sb)->priv_root); 65 struct dentry *xaroot; 66 67 /* This needs to be created at mount-time */ 68 if (!privroot) 69 return ERR_PTR(-ENODATA); 70 71 mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR); 72 if (REISERFS_SB(sb)->xattr_root) { 73 xaroot = dget(REISERFS_SB(sb)->xattr_root); 74 goto out; 75 } 76 77 xaroot = lookup_one_len(XAROOT_NAME, privroot, strlen(XAROOT_NAME)); 78 if (IS_ERR(xaroot)) { 79 goto out; 80 } else if (!xaroot->d_inode) { 81 int err = -ENODATA; 82 if (flags == 0 || flags & XATTR_CREATE) 83 err = privroot->d_inode->i_op->mkdir(privroot->d_inode, 84 xaroot, 0700); 85 if (err) { 86 dput(xaroot); 87 xaroot = ERR_PTR(err); 88 goto out; 89 } 90 } 91 REISERFS_SB(sb)->xattr_root = dget(xaroot); 92 93 out: 94 mutex_unlock(&privroot->d_inode->i_mutex); 95 dput(privroot); 96 return xaroot; 97 } 98 99 /* Opens the directory corresponding to the inode's extended attribute store. 100 * If flags allow, the tree to the directory may be created. If creation is 101 * prohibited, -ENODATA is returned. */ 102 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 103 { 104 struct dentry *xaroot, *xadir; 105 char namebuf[17]; 106 107 xaroot = get_xa_root(inode->i_sb, flags); 108 if (IS_ERR(xaroot)) 109 return xaroot; 110 111 /* ok, we have xaroot open */ 112 snprintf(namebuf, sizeof(namebuf), "%X.%X", 113 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 114 inode->i_generation); 115 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); 116 if (IS_ERR(xadir)) { 117 dput(xaroot); 118 return xadir; 119 } 120 121 if (!xadir->d_inode) { 122 int err; 123 if (flags == 0 || flags & XATTR_CREATE) { 124 /* Although there is nothing else trying to create this directory, 125 * another directory with the same hash may be created, so we need 126 * to protect against that */ 127 err = 128 xaroot->d_inode->i_op->mkdir(xaroot->d_inode, xadir, 129 0700); 130 if (err) { 131 dput(xaroot); 132 dput(xadir); 133 return ERR_PTR(err); 134 } 135 } 136 if (!xadir->d_inode) { 137 dput(xaroot); 138 dput(xadir); 139 return ERR_PTR(-ENODATA); 140 } 141 } 142 143 dput(xaroot); 144 return xadir; 145 } 146 147 /* Returns a dentry corresponding to a specific extended attribute file 148 * for the inode. If flags allow, the file is created. Otherwise, a 149 * valid or negative dentry, or an error is returned. */ 150 static struct dentry *get_xa_file_dentry(const struct inode *inode, 151 const char *name, int flags) 152 { 153 struct dentry *xadir, *xafile; 154 int err = 0; 155 156 xadir = open_xa_dir(inode, flags); 157 if (IS_ERR(xadir)) { 158 return ERR_CAST(xadir); 159 } else if (xadir && !xadir->d_inode) { 160 dput(xadir); 161 return ERR_PTR(-ENODATA); 162 } 163 164 xafile = lookup_one_len(name, xadir, strlen(name)); 165 if (IS_ERR(xafile)) { 166 dput(xadir); 167 return ERR_CAST(xafile); 168 } 169 170 if (xafile->d_inode) { /* file exists */ 171 if (flags & XATTR_CREATE) { 172 err = -EEXIST; 173 dput(xafile); 174 goto out; 175 } 176 } else if (flags & XATTR_REPLACE || flags & FL_READONLY) { 177 goto out; 178 } else { 179 /* inode->i_mutex is down, so nothing else can try to create 180 * the same xattr */ 181 err = xadir->d_inode->i_op->create(xadir->d_inode, xafile, 182 0700 | S_IFREG, NULL); 183 184 if (err) { 185 dput(xafile); 186 goto out; 187 } 188 } 189 190 out: 191 dput(xadir); 192 if (err) 193 xafile = ERR_PTR(err); 194 else if (!xafile->d_inode) { 195 dput(xafile); 196 xafile = ERR_PTR(-ENODATA); 197 } 198 return xafile; 199 } 200 201 /* 202 * this is very similar to fs/reiserfs/dir.c:reiserfs_readdir, but 203 * we need to drop the path before calling the filldir struct. That 204 * would be a big performance hit to the non-xattr case, so I've copied 205 * the whole thing for now. --clm 206 * 207 * the big difference is that I go backwards through the directory, 208 * and don't mess with f->f_pos, but the idea is the same. Do some 209 * action on each and every entry in the directory. 210 * 211 * we're called with i_mutex held, so there are no worries about the directory 212 * changing underneath us. 213 */ 214 static int __xattr_readdir(struct inode *inode, void *dirent, filldir_t filldir) 215 { 216 struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */ 217 INITIALIZE_PATH(path_to_entry); 218 struct buffer_head *bh; 219 int entry_num; 220 struct item_head *ih, tmp_ih; 221 int search_res; 222 char *local_buf; 223 loff_t next_pos; 224 char small_buf[32]; /* avoid kmalloc if we can */ 225 struct reiserfs_de_head *deh; 226 int d_reclen; 227 char *d_name; 228 off_t d_off; 229 ino_t d_ino; 230 struct reiserfs_dir_entry de; 231 232 /* form key for search the next directory entry using f_pos field of 233 file structure */ 234 next_pos = max_reiserfs_offset(inode); 235 236 while (1) { 237 research: 238 if (next_pos <= DOT_DOT_OFFSET) 239 break; 240 make_cpu_key(&pos_key, inode, next_pos, TYPE_DIRENTRY, 3); 241 242 search_res = 243 search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry, 244 &de); 245 if (search_res == IO_ERROR) { 246 // FIXME: we could just skip part of directory which could 247 // not be read 248 pathrelse(&path_to_entry); 249 return -EIO; 250 } 251 252 if (search_res == NAME_NOT_FOUND) 253 de.de_entry_num--; 254 255 set_de_name_and_namelen(&de); 256 entry_num = de.de_entry_num; 257 deh = &(de.de_deh[entry_num]); 258 259 bh = de.de_bh; 260 ih = de.de_ih; 261 262 if (!is_direntry_le_ih(ih)) { 263 reiserfs_warning(inode->i_sb, "not direntry %h", ih); 264 break; 265 } 266 copy_item_head(&tmp_ih, ih); 267 268 /* we must have found item, that is item of this directory, */ 269 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key), 270 "vs-9000: found item %h does not match to dir we readdir %K", 271 ih, &pos_key); 272 273 if (deh_offset(deh) <= DOT_DOT_OFFSET) { 274 break; 275 } 276 277 /* look for the previous entry in the directory */ 278 next_pos = deh_offset(deh) - 1; 279 280 if (!de_visible(deh)) 281 /* it is hidden entry */ 282 continue; 283 284 d_reclen = entry_length(bh, ih, entry_num); 285 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh); 286 d_off = deh_offset(deh); 287 d_ino = deh_objectid(deh); 288 289 if (!d_name[d_reclen - 1]) 290 d_reclen = strlen(d_name); 291 292 if (d_reclen > REISERFS_MAX_NAME(inode->i_sb->s_blocksize)) { 293 /* too big to send back to VFS */ 294 continue; 295 } 296 297 /* Ignore the .reiserfs_priv entry */ 298 if (reiserfs_xattrs(inode->i_sb) && 299 !old_format_only(inode->i_sb) && 300 deh_objectid(deh) == 301 le32_to_cpu(INODE_PKEY 302 (REISERFS_SB(inode->i_sb)->priv_root->d_inode)-> 303 k_objectid)) 304 continue; 305 306 if (d_reclen <= 32) { 307 local_buf = small_buf; 308 } else { 309 local_buf = kmalloc(d_reclen, GFP_NOFS); 310 if (!local_buf) { 311 pathrelse(&path_to_entry); 312 return -ENOMEM; 313 } 314 if (item_moved(&tmp_ih, &path_to_entry)) { 315 kfree(local_buf); 316 317 /* sigh, must retry. Do this same offset again */ 318 next_pos = d_off; 319 goto research; 320 } 321 } 322 323 // Note, that we copy name to user space via temporary 324 // buffer (local_buf) because filldir will block if 325 // user space buffer is swapped out. At that time 326 // entry can move to somewhere else 327 memcpy(local_buf, d_name, d_reclen); 328 329 /* the filldir function might need to start transactions, 330 * or do who knows what. Release the path now that we've 331 * copied all the important stuff out of the deh 332 */ 333 pathrelse(&path_to_entry); 334 335 if (filldir(dirent, local_buf, d_reclen, d_off, d_ino, 336 DT_UNKNOWN) < 0) { 337 if (local_buf != small_buf) { 338 kfree(local_buf); 339 } 340 goto end; 341 } 342 if (local_buf != small_buf) { 343 kfree(local_buf); 344 } 345 } /* while */ 346 347 end: 348 pathrelse(&path_to_entry); 349 return 0; 350 } 351 352 /* 353 * this could be done with dedicated readdir ops for the xattr files, 354 * but I want to get something working asap 355 * this is stolen from vfs_readdir 356 * 357 */ 358 static 359 int xattr_readdir(struct inode *inode, filldir_t filler, void *buf) 360 { 361 int res = -ENOENT; 362 mutex_lock_nested(&inode->i_mutex, I_MUTEX_XATTR); 363 if (!IS_DEADDIR(inode)) { 364 lock_kernel(); 365 res = __xattr_readdir(inode, buf, filler); 366 unlock_kernel(); 367 } 368 mutex_unlock(&inode->i_mutex); 369 return res; 370 } 371 372 /* Internal operations on file data */ 373 static inline void reiserfs_put_page(struct page *page) 374 { 375 kunmap(page); 376 page_cache_release(page); 377 } 378 379 static struct page *reiserfs_get_page(struct inode *dir, unsigned long n) 380 { 381 struct address_space *mapping = dir->i_mapping; 382 struct page *page; 383 /* We can deadlock if we try to free dentries, 384 and an unlink/rmdir has just occured - GFP_NOFS avoids this */ 385 mapping_set_gfp_mask(mapping, GFP_NOFS); 386 page = read_mapping_page(mapping, n, NULL); 387 if (!IS_ERR(page)) { 388 kmap(page); 389 if (PageError(page)) 390 goto fail; 391 } 392 return page; 393 394 fail: 395 reiserfs_put_page(page); 396 return ERR_PTR(-EIO); 397 } 398 399 static inline __u32 xattr_hash(const char *msg, int len) 400 { 401 return csum_partial(msg, len, 0); 402 } 403 404 int reiserfs_commit_write(struct file *f, struct page *page, 405 unsigned from, unsigned to); 406 int reiserfs_prepare_write(struct file *f, struct page *page, 407 unsigned from, unsigned to); 408 409 410 /* Generic extended attribute operations that can be used by xa plugins */ 411 412 /* 413 * inode->i_mutex: down 414 */ 415 int 416 reiserfs_xattr_set(struct inode *inode, const char *name, const void *buffer, 417 size_t buffer_size, int flags) 418 { 419 int err = 0; 420 struct dentry *dentry; 421 struct page *page; 422 char *data; 423 struct address_space *mapping; 424 size_t file_pos = 0; 425 size_t buffer_pos = 0; 426 struct inode *xinode; 427 struct iattr newattrs; 428 __u32 xahash = 0; 429 430 if (get_inode_sd_version(inode) == STAT_DATA_V1) 431 return -EOPNOTSUPP; 432 433 /* Empty xattrs are ok, they're just empty files, no hash */ 434 if (buffer && buffer_size) 435 xahash = xattr_hash(buffer, buffer_size); 436 437 open_file: 438 dentry = get_xa_file_dentry(inode, name, flags); 439 if (IS_ERR(dentry)) { 440 err = PTR_ERR(dentry); 441 goto out; 442 } 443 444 xinode = dentry->d_inode; 445 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 446 447 /* we need to copy it off.. */ 448 if (xinode->i_nlink > 1) { 449 dput(dentry); 450 err = reiserfs_xattr_del(inode, name); 451 if (err < 0) 452 goto out; 453 /* We just killed the old one, we're not replacing anymore */ 454 if (flags & XATTR_REPLACE) 455 flags &= ~XATTR_REPLACE; 456 goto open_file; 457 } 458 459 /* Resize it so we're ok to write there */ 460 newattrs.ia_size = buffer_size; 461 newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; 462 mutex_lock_nested(&xinode->i_mutex, I_MUTEX_XATTR); 463 err = notify_change(dentry, &newattrs); 464 if (err) 465 goto out_filp; 466 467 mapping = xinode->i_mapping; 468 while (buffer_pos < buffer_size || buffer_pos == 0) { 469 size_t chunk; 470 size_t skip = 0; 471 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 472 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 473 chunk = PAGE_CACHE_SIZE; 474 else 475 chunk = buffer_size - buffer_pos; 476 477 page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT); 478 if (IS_ERR(page)) { 479 err = PTR_ERR(page); 480 goto out_filp; 481 } 482 483 lock_page(page); 484 data = page_address(page); 485 486 if (file_pos == 0) { 487 struct reiserfs_xattr_header *rxh; 488 skip = file_pos = sizeof(struct reiserfs_xattr_header); 489 if (chunk + skip > PAGE_CACHE_SIZE) 490 chunk = PAGE_CACHE_SIZE - skip; 491 rxh = (struct reiserfs_xattr_header *)data; 492 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 493 rxh->h_hash = cpu_to_le32(xahash); 494 } 495 496 err = reiserfs_prepare_write(NULL, page, page_offset, 497 page_offset + chunk + skip); 498 if (!err) { 499 if (buffer) 500 memcpy(data + skip, buffer + buffer_pos, chunk); 501 err = reiserfs_commit_write(NULL, page, page_offset, 502 page_offset + chunk + 503 skip); 504 } 505 unlock_page(page); 506 reiserfs_put_page(page); 507 buffer_pos += chunk; 508 file_pos += chunk; 509 skip = 0; 510 if (err || buffer_size == 0 || !buffer) 511 break; 512 } 513 514 /* We can't mark the inode dirty if it's not hashed. This is the case 515 * when we're inheriting the default ACL. If we dirty it, the inode 516 * gets marked dirty, but won't (ever) make it onto the dirty list until 517 * it's synced explicitly to clear I_DIRTY. This is bad. */ 518 if (!hlist_unhashed(&inode->i_hash)) { 519 inode->i_ctime = CURRENT_TIME_SEC; 520 mark_inode_dirty(inode); 521 } 522 523 out_filp: 524 mutex_unlock(&xinode->i_mutex); 525 dput(dentry); 526 527 out: 528 return err; 529 } 530 531 /* 532 * inode->i_mutex: down 533 */ 534 int 535 reiserfs_xattr_get(const struct inode *inode, const char *name, void *buffer, 536 size_t buffer_size) 537 { 538 ssize_t err = 0; 539 struct dentry *dentry; 540 size_t isize; 541 size_t file_pos = 0; 542 size_t buffer_pos = 0; 543 struct page *page; 544 struct inode *xinode; 545 __u32 hash = 0; 546 547 if (name == NULL) 548 return -EINVAL; 549 550 /* We can't have xattrs attached to v1 items since they don't have 551 * generation numbers */ 552 if (get_inode_sd_version(inode) == STAT_DATA_V1) 553 return -EOPNOTSUPP; 554 555 dentry = get_xa_file_dentry(inode, name, FL_READONLY); 556 if (IS_ERR(dentry)) { 557 err = PTR_ERR(dentry); 558 goto out; 559 } 560 561 xinode = dentry->d_inode; 562 isize = xinode->i_size; 563 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 564 565 /* Just return the size needed */ 566 if (buffer == NULL) { 567 err = isize - sizeof(struct reiserfs_xattr_header); 568 goto out_dput; 569 } 570 571 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 572 err = -ERANGE; 573 goto out_dput; 574 } 575 576 while (file_pos < isize) { 577 size_t chunk; 578 char *data; 579 size_t skip = 0; 580 if (isize - file_pos > PAGE_CACHE_SIZE) 581 chunk = PAGE_CACHE_SIZE; 582 else 583 chunk = isize - file_pos; 584 585 page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT); 586 if (IS_ERR(page)) { 587 err = PTR_ERR(page); 588 goto out_dput; 589 } 590 591 lock_page(page); 592 data = page_address(page); 593 if (file_pos == 0) { 594 struct reiserfs_xattr_header *rxh = 595 (struct reiserfs_xattr_header *)data; 596 skip = file_pos = sizeof(struct reiserfs_xattr_header); 597 chunk -= skip; 598 /* Magic doesn't match up.. */ 599 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 600 unlock_page(page); 601 reiserfs_put_page(page); 602 reiserfs_warning(inode->i_sb, 603 "Invalid magic for xattr (%s) " 604 "associated with %k", name, 605 INODE_PKEY(inode)); 606 err = -EIO; 607 goto out_dput; 608 } 609 hash = le32_to_cpu(rxh->h_hash); 610 } 611 memcpy(buffer + buffer_pos, data + skip, chunk); 612 unlock_page(page); 613 reiserfs_put_page(page); 614 file_pos += chunk; 615 buffer_pos += chunk; 616 skip = 0; 617 } 618 err = isize - sizeof(struct reiserfs_xattr_header); 619 620 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 621 hash) { 622 reiserfs_warning(inode->i_sb, 623 "Invalid hash for xattr (%s) associated " 624 "with %k", name, INODE_PKEY(inode)); 625 err = -EIO; 626 } 627 628 out_dput: 629 dput(dentry); 630 631 out: 632 return err; 633 } 634 635 static int 636 __reiserfs_xattr_del(struct dentry *xadir, const char *name, int namelen) 637 { 638 struct dentry *dentry; 639 struct inode *dir = xadir->d_inode; 640 int err = 0; 641 642 dentry = lookup_one_len(name, xadir, namelen); 643 if (IS_ERR(dentry)) { 644 err = PTR_ERR(dentry); 645 goto out; 646 } else if (!dentry->d_inode) { 647 err = -ENODATA; 648 goto out_file; 649 } 650 651 /* Skip directories.. */ 652 if (S_ISDIR(dentry->d_inode->i_mode)) 653 goto out_file; 654 655 if (!is_reiserfs_priv_object(dentry->d_inode)) { 656 reiserfs_warning(dir->i_sb, "OID %08x [%.*s/%.*s] doesn't have " 657 "priv flag set [parent is %sset].", 658 le32_to_cpu(INODE_PKEY(dentry->d_inode)-> 659 k_objectid), xadir->d_name.len, 660 xadir->d_name.name, namelen, name, 661 is_reiserfs_priv_object(xadir-> 662 d_inode) ? "" : 663 "not "); 664 dput(dentry); 665 return -EIO; 666 } 667 668 err = dir->i_op->unlink(dir, dentry); 669 if (!err) 670 d_delete(dentry); 671 672 out_file: 673 dput(dentry); 674 675 out: 676 return err; 677 } 678 679 int reiserfs_xattr_del(struct inode *inode, const char *name) 680 { 681 struct dentry *dir; 682 int err; 683 684 dir = open_xa_dir(inode, FL_READONLY); 685 if (IS_ERR(dir)) { 686 err = PTR_ERR(dir); 687 goto out; 688 } 689 690 err = __reiserfs_xattr_del(dir, name, strlen(name)); 691 dput(dir); 692 693 if (!err) { 694 inode->i_ctime = CURRENT_TIME_SEC; 695 mark_inode_dirty(inode); 696 } 697 698 out: 699 return err; 700 } 701 702 /* The following are side effects of other operations that aren't explicitly 703 * modifying extended attributes. This includes operations such as permissions 704 * or ownership changes, object deletions, etc. */ 705 706 static int 707 reiserfs_delete_xattrs_filler(void *buf, const char *name, int namelen, 708 loff_t offset, u64 ino, unsigned int d_type) 709 { 710 struct dentry *xadir = (struct dentry *)buf; 711 712 return __reiserfs_xattr_del(xadir, name, namelen); 713 714 } 715 716 /* This is called w/ inode->i_mutex downed */ 717 int reiserfs_delete_xattrs(struct inode *inode) 718 { 719 struct dentry *dir, *root; 720 int err = 0; 721 722 /* Skip out, an xattr has no xattrs associated with it */ 723 if (is_reiserfs_priv_object(inode) || 724 get_inode_sd_version(inode) == STAT_DATA_V1 || 725 !reiserfs_xattrs(inode->i_sb)) { 726 return 0; 727 } 728 reiserfs_read_lock_xattrs(inode->i_sb); 729 dir = open_xa_dir(inode, FL_READONLY); 730 reiserfs_read_unlock_xattrs(inode->i_sb); 731 if (IS_ERR(dir)) { 732 err = PTR_ERR(dir); 733 goto out; 734 } else if (!dir->d_inode) { 735 dput(dir); 736 return 0; 737 } 738 739 lock_kernel(); 740 err = xattr_readdir(dir->d_inode, reiserfs_delete_xattrs_filler, dir); 741 if (err) { 742 unlock_kernel(); 743 goto out_dir; 744 } 745 746 /* Leftovers besides . and .. -- that's not good. */ 747 if (dir->d_inode->i_nlink <= 2) { 748 root = get_xa_root(inode->i_sb, XATTR_REPLACE); 749 reiserfs_write_lock_xattrs(inode->i_sb); 750 err = vfs_rmdir(root->d_inode, dir); 751 reiserfs_write_unlock_xattrs(inode->i_sb); 752 dput(root); 753 } else { 754 reiserfs_warning(inode->i_sb, 755 "Couldn't remove all entries in directory"); 756 } 757 unlock_kernel(); 758 759 out_dir: 760 dput(dir); 761 762 out: 763 if (!err) 764 REISERFS_I(inode)->i_flags = 765 REISERFS_I(inode)->i_flags & ~i_has_xattr_dir; 766 return err; 767 } 768 769 struct reiserfs_chown_buf { 770 struct inode *inode; 771 struct dentry *xadir; 772 struct iattr *attrs; 773 }; 774 775 /* XXX: If there is a better way to do this, I'd love to hear about it */ 776 static int 777 reiserfs_chown_xattrs_filler(void *buf, const char *name, int namelen, 778 loff_t offset, u64 ino, unsigned int d_type) 779 { 780 struct reiserfs_chown_buf *chown_buf = (struct reiserfs_chown_buf *)buf; 781 struct dentry *xafile, *xadir = chown_buf->xadir; 782 struct iattr *attrs = chown_buf->attrs; 783 int err = 0; 784 785 xafile = lookup_one_len(name, xadir, namelen); 786 if (IS_ERR(xafile)) 787 return PTR_ERR(xafile); 788 else if (!xafile->d_inode) { 789 dput(xafile); 790 return -ENODATA; 791 } 792 793 if (!S_ISDIR(xafile->d_inode->i_mode)) 794 err = notify_change(xafile, attrs); 795 dput(xafile); 796 797 return err; 798 } 799 800 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 801 { 802 struct dentry *dir; 803 int err = 0; 804 struct reiserfs_chown_buf buf; 805 unsigned int ia_valid = attrs->ia_valid; 806 807 /* Skip out, an xattr has no xattrs associated with it */ 808 if (is_reiserfs_priv_object(inode) || 809 get_inode_sd_version(inode) == STAT_DATA_V1 || 810 !reiserfs_xattrs(inode->i_sb)) { 811 return 0; 812 } 813 reiserfs_read_lock_xattrs(inode->i_sb); 814 dir = open_xa_dir(inode, FL_READONLY); 815 reiserfs_read_unlock_xattrs(inode->i_sb); 816 if (IS_ERR(dir)) { 817 if (PTR_ERR(dir) != -ENODATA) 818 err = PTR_ERR(dir); 819 goto out; 820 } else if (!dir->d_inode) { 821 dput(dir); 822 goto out; 823 } 824 825 lock_kernel(); 826 827 attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME); 828 buf.xadir = dir; 829 buf.attrs = attrs; 830 buf.inode = inode; 831 832 err = xattr_readdir(dir->d_inode, reiserfs_chown_xattrs_filler, &buf); 833 if (err) { 834 unlock_kernel(); 835 goto out_dir; 836 } 837 838 err = notify_change(dir, attrs); 839 unlock_kernel(); 840 841 out_dir: 842 dput(dir); 843 844 out: 845 attrs->ia_valid = ia_valid; 846 return err; 847 } 848 849 /* Actual operations that are exported to VFS-land */ 850 851 /* 852 * Inode operation getxattr() 853 * Preliminary locking: we down dentry->d_inode->i_mutex 854 */ 855 ssize_t 856 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 857 size_t size) 858 { 859 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 860 int err; 861 862 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 863 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 864 return -EOPNOTSUPP; 865 866 reiserfs_read_lock_xattr_i(dentry->d_inode); 867 reiserfs_read_lock_xattrs(dentry->d_sb); 868 err = xah->get(dentry->d_inode, name, buffer, size); 869 reiserfs_read_unlock_xattrs(dentry->d_sb); 870 reiserfs_read_unlock_xattr_i(dentry->d_inode); 871 return err; 872 } 873 874 /* 875 * Inode operation setxattr() 876 * 877 * dentry->d_inode->i_mutex down 878 */ 879 int 880 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 881 size_t size, int flags) 882 { 883 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 884 int err; 885 int lock; 886 887 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 888 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 889 return -EOPNOTSUPP; 890 891 reiserfs_write_lock_xattr_i(dentry->d_inode); 892 lock = !has_xattr_dir(dentry->d_inode); 893 if (lock) 894 reiserfs_write_lock_xattrs(dentry->d_sb); 895 else 896 reiserfs_read_lock_xattrs(dentry->d_sb); 897 err = xah->set(dentry->d_inode, name, value, size, flags); 898 if (lock) 899 reiserfs_write_unlock_xattrs(dentry->d_sb); 900 else 901 reiserfs_read_unlock_xattrs(dentry->d_sb); 902 reiserfs_write_unlock_xattr_i(dentry->d_inode); 903 return err; 904 } 905 906 /* 907 * Inode operation removexattr() 908 * 909 * dentry->d_inode->i_mutex down 910 */ 911 int reiserfs_removexattr(struct dentry *dentry, const char *name) 912 { 913 int err; 914 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 915 916 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 917 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 918 return -EOPNOTSUPP; 919 920 reiserfs_write_lock_xattr_i(dentry->d_inode); 921 reiserfs_read_lock_xattrs(dentry->d_sb); 922 923 /* Deletion pre-operation */ 924 if (xah->del) { 925 err = xah->del(dentry->d_inode, name); 926 if (err) 927 goto out; 928 } 929 930 err = reiserfs_xattr_del(dentry->d_inode, name); 931 932 dentry->d_inode->i_ctime = CURRENT_TIME_SEC; 933 mark_inode_dirty(dentry->d_inode); 934 935 out: 936 reiserfs_read_unlock_xattrs(dentry->d_sb); 937 reiserfs_write_unlock_xattr_i(dentry->d_inode); 938 return err; 939 } 940 941 /* This is what filldir will use: 942 * r_pos will always contain the amount of space required for the entire 943 * list. If r_pos becomes larger than r_size, we need more space and we 944 * return an error indicating this. If r_pos is less than r_size, then we've 945 * filled the buffer successfully and we return success */ 946 struct reiserfs_listxattr_buf { 947 int r_pos; 948 int r_size; 949 char *r_buf; 950 struct inode *r_inode; 951 }; 952 953 static int 954 reiserfs_listxattr_filler(void *buf, const char *name, int namelen, 955 loff_t offset, u64 ino, unsigned int d_type) 956 { 957 struct reiserfs_listxattr_buf *b = (struct reiserfs_listxattr_buf *)buf; 958 int len = 0; 959 if (name[0] != '.' 960 || (namelen != 1 && (name[1] != '.' || namelen != 2))) { 961 struct reiserfs_xattr_handler *xah = 962 find_xattr_handler_prefix(name); 963 if (!xah) 964 return 0; /* Unsupported xattr name, skip it */ 965 966 /* We call ->list() twice because the operation isn't required to just 967 * return the name back - we want to make sure we have enough space */ 968 len += xah->list(b->r_inode, name, namelen, NULL); 969 970 if (len) { 971 if (b->r_pos + len + 1 <= b->r_size) { 972 char *p = b->r_buf + b->r_pos; 973 p += xah->list(b->r_inode, name, namelen, p); 974 *p++ = '\0'; 975 } 976 b->r_pos += len + 1; 977 } 978 } 979 980 return 0; 981 } 982 983 /* 984 * Inode operation listxattr() 985 * 986 * Preliminary locking: we down dentry->d_inode->i_mutex 987 */ 988 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 989 { 990 struct dentry *dir; 991 int err = 0; 992 struct reiserfs_listxattr_buf buf; 993 994 if (!dentry->d_inode) 995 return -EINVAL; 996 997 if (!reiserfs_xattrs(dentry->d_sb) || 998 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 999 return -EOPNOTSUPP; 1000 1001 reiserfs_read_lock_xattr_i(dentry->d_inode); 1002 reiserfs_read_lock_xattrs(dentry->d_sb); 1003 dir = open_xa_dir(dentry->d_inode, FL_READONLY); 1004 reiserfs_read_unlock_xattrs(dentry->d_sb); 1005 if (IS_ERR(dir)) { 1006 err = PTR_ERR(dir); 1007 if (err == -ENODATA) 1008 err = 0; /* Not an error if there aren't any xattrs */ 1009 goto out; 1010 } 1011 1012 buf.r_buf = buffer; 1013 buf.r_size = buffer ? size : 0; 1014 buf.r_pos = 0; 1015 buf.r_inode = dentry->d_inode; 1016 1017 REISERFS_I(dentry->d_inode)->i_flags |= i_has_xattr_dir; 1018 1019 err = xattr_readdir(dir->d_inode, reiserfs_listxattr_filler, &buf); 1020 if (err) 1021 goto out_dir; 1022 1023 if (buf.r_pos > buf.r_size && buffer != NULL) 1024 err = -ERANGE; 1025 else 1026 err = buf.r_pos; 1027 1028 out_dir: 1029 dput(dir); 1030 1031 out: 1032 reiserfs_read_unlock_xattr_i(dentry->d_inode); 1033 return err; 1034 } 1035 1036 /* This is the implementation for the xattr plugin infrastructure */ 1037 static LIST_HEAD(xattr_handlers); 1038 static DEFINE_RWLOCK(handler_lock); 1039 1040 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char 1041 *prefix) 1042 { 1043 struct reiserfs_xattr_handler *xah = NULL; 1044 struct list_head *p; 1045 1046 read_lock(&handler_lock); 1047 list_for_each(p, &xattr_handlers) { 1048 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1049 if (strncmp(xah->prefix, prefix, strlen(xah->prefix)) == 0) 1050 break; 1051 xah = NULL; 1052 } 1053 1054 read_unlock(&handler_lock); 1055 return xah; 1056 } 1057 1058 static void __unregister_handlers(void) 1059 { 1060 struct reiserfs_xattr_handler *xah; 1061 struct list_head *p, *tmp; 1062 1063 list_for_each_safe(p, tmp, &xattr_handlers) { 1064 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1065 if (xah->exit) 1066 xah->exit(); 1067 1068 list_del_init(p); 1069 } 1070 INIT_LIST_HEAD(&xattr_handlers); 1071 } 1072 1073 int __init reiserfs_xattr_register_handlers(void) 1074 { 1075 int err = 0; 1076 struct reiserfs_xattr_handler *xah; 1077 struct list_head *p; 1078 1079 write_lock(&handler_lock); 1080 1081 /* If we're already initialized, nothing to do */ 1082 if (!list_empty(&xattr_handlers)) { 1083 write_unlock(&handler_lock); 1084 return 0; 1085 } 1086 1087 /* Add the handlers */ 1088 list_add_tail(&user_handler.handlers, &xattr_handlers); 1089 list_add_tail(&trusted_handler.handlers, &xattr_handlers); 1090 #ifdef CONFIG_REISERFS_FS_SECURITY 1091 list_add_tail(&security_handler.handlers, &xattr_handlers); 1092 #endif 1093 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 1094 list_add_tail(&posix_acl_access_handler.handlers, &xattr_handlers); 1095 list_add_tail(&posix_acl_default_handler.handlers, &xattr_handlers); 1096 #endif 1097 1098 /* Run initializers, if available */ 1099 list_for_each(p, &xattr_handlers) { 1100 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1101 if (xah->init) { 1102 err = xah->init(); 1103 if (err) { 1104 list_del_init(p); 1105 break; 1106 } 1107 } 1108 } 1109 1110 /* Clean up other handlers, if any failed */ 1111 if (err) 1112 __unregister_handlers(); 1113 1114 write_unlock(&handler_lock); 1115 return err; 1116 } 1117 1118 void reiserfs_xattr_unregister_handlers(void) 1119 { 1120 write_lock(&handler_lock); 1121 __unregister_handlers(); 1122 write_unlock(&handler_lock); 1123 } 1124 1125 /* This will catch lookups from the fs root to .reiserfs_priv */ 1126 static int 1127 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 1128 { 1129 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 1130 if (name->len == priv_root->d_name.len && 1131 name->hash == priv_root->d_name.hash && 1132 !memcmp(name->name, priv_root->d_name.name, name->len)) { 1133 return -ENOENT; 1134 } else if (q1->len == name->len && 1135 !memcmp(q1->name, name->name, name->len)) 1136 return 0; 1137 return 1; 1138 } 1139 1140 static struct dentry_operations xattr_lookup_poison_ops = { 1141 .d_compare = xattr_lookup_poison, 1142 }; 1143 1144 /* We need to take a copy of the mount flags since things like 1145 * MS_RDONLY don't get set until *after* we're called. 1146 * mount_flags != mount_options */ 1147 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1148 { 1149 int err = 0; 1150 1151 /* We need generation numbers to ensure that the oid mapping is correct 1152 * v3.5 filesystems don't have them. */ 1153 if (!old_format_only(s)) { 1154 set_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1155 } else if (reiserfs_xattrs_optional(s)) { 1156 /* Old format filesystem, but optional xattrs have been enabled 1157 * at mount time. Error out. */ 1158 reiserfs_warning(s, "xattrs/ACLs not supported on pre v3.6 " 1159 "format filesystem. Failing mount."); 1160 err = -EOPNOTSUPP; 1161 goto error; 1162 } else { 1163 /* Old format filesystem, but no optional xattrs have been enabled. This 1164 * means we silently disable xattrs on the filesystem. */ 1165 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1166 } 1167 1168 /* If we don't have the privroot located yet - go find it */ 1169 if (reiserfs_xattrs(s) && !REISERFS_SB(s)->priv_root) { 1170 struct dentry *dentry; 1171 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 1172 strlen(PRIVROOT_NAME)); 1173 if (!IS_ERR(dentry)) { 1174 if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) { 1175 struct inode *inode = dentry->d_parent->d_inode; 1176 mutex_lock_nested(&inode->i_mutex, 1177 I_MUTEX_XATTR); 1178 err = inode->i_op->mkdir(inode, dentry, 0700); 1179 mutex_unlock(&inode->i_mutex); 1180 if (err) { 1181 dput(dentry); 1182 dentry = NULL; 1183 } 1184 1185 if (dentry && dentry->d_inode) 1186 reiserfs_warning(s, 1187 "Created %s on %s - reserved for " 1188 "xattr storage.", 1189 PRIVROOT_NAME, 1190 reiserfs_bdevname 1191 (inode->i_sb)); 1192 } else if (!dentry->d_inode) { 1193 dput(dentry); 1194 dentry = NULL; 1195 } 1196 } else 1197 err = PTR_ERR(dentry); 1198 1199 if (!err && dentry) { 1200 s->s_root->d_op = &xattr_lookup_poison_ops; 1201 reiserfs_mark_inode_private(dentry->d_inode); 1202 REISERFS_SB(s)->priv_root = dentry; 1203 } else if (!(mount_flags & MS_RDONLY)) { /* xattrs are unavailable */ 1204 /* If we're read-only it just means that the dir hasn't been 1205 * created. Not an error -- just no xattrs on the fs. We'll 1206 * check again if we go read-write */ 1207 reiserfs_warning(s, "xattrs/ACLs enabled and couldn't " 1208 "find/create .reiserfs_priv. Failing mount."); 1209 err = -EOPNOTSUPP; 1210 } 1211 } 1212 1213 error: 1214 /* This is only nonzero if there was an error initializing the xattr 1215 * directory or if there is a condition where we don't support them. */ 1216 if (err) { 1217 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1218 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1219 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1220 } 1221 1222 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1223 s->s_flags = s->s_flags & ~MS_POSIXACL; 1224 if (reiserfs_posixacl(s)) 1225 s->s_flags |= MS_POSIXACL; 1226 1227 return err; 1228 } 1229 1230 static int reiserfs_check_acl(struct inode *inode, int mask) 1231 { 1232 struct posix_acl *acl; 1233 int error = -EAGAIN; /* do regular unix permission checks by default */ 1234 1235 reiserfs_read_lock_xattr_i(inode); 1236 reiserfs_read_lock_xattrs(inode->i_sb); 1237 1238 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 1239 1240 reiserfs_read_unlock_xattrs(inode->i_sb); 1241 reiserfs_read_unlock_xattr_i(inode); 1242 1243 if (acl) { 1244 if (!IS_ERR(acl)) { 1245 error = posix_acl_permission(inode, acl, mask); 1246 posix_acl_release(acl); 1247 } else if (PTR_ERR(acl) != -ENODATA) 1248 error = PTR_ERR(acl); 1249 } 1250 1251 return error; 1252 } 1253 1254 int reiserfs_permission(struct inode *inode, int mask, struct nameidata *nd) 1255 { 1256 /* 1257 * We don't do permission checks on the internal objects. 1258 * Permissions are determined by the "owning" object. 1259 */ 1260 if (is_reiserfs_priv_object(inode)) 1261 return 0; 1262 1263 /* 1264 * Stat data v1 doesn't support ACLs. 1265 */ 1266 if (get_inode_sd_version(inode) == STAT_DATA_V1) 1267 return generic_permission(inode, mask, NULL); 1268 else 1269 return generic_permission(inode, mask, reiserfs_check_acl); 1270 } 1271