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 static struct dentry *create_xa_root(struct super_block *sb) 58 { 59 struct dentry *privroot = dget(REISERFS_SB(sb)->priv_root); 60 struct dentry *xaroot; 61 62 /* This needs to be created at mount-time */ 63 if (!privroot) 64 return ERR_PTR(-EOPNOTSUPP); 65 66 xaroot = lookup_one_len(XAROOT_NAME, privroot, strlen(XAROOT_NAME)); 67 if (IS_ERR(xaroot)) { 68 goto out; 69 } else if (!xaroot->d_inode) { 70 int err; 71 mutex_lock(&privroot->d_inode->i_mutex); 72 err = 73 privroot->d_inode->i_op->mkdir(privroot->d_inode, xaroot, 74 0700); 75 mutex_unlock(&privroot->d_inode->i_mutex); 76 77 if (err) { 78 dput(xaroot); 79 dput(privroot); 80 return ERR_PTR(err); 81 } 82 REISERFS_SB(sb)->xattr_root = dget(xaroot); 83 } 84 85 out: 86 dput(privroot); 87 return xaroot; 88 } 89 90 /* This will return a dentry, or error, refering to the xa root directory. 91 * If the xa root doesn't exist yet, the dentry will be returned without 92 * an associated inode. This dentry can be used with ->mkdir to create 93 * the xa directory. */ 94 static struct dentry *__get_xa_root(struct super_block *s) 95 { 96 struct dentry *privroot = dget(REISERFS_SB(s)->priv_root); 97 struct dentry *xaroot = NULL; 98 99 if (IS_ERR(privroot) || !privroot) 100 return privroot; 101 102 xaroot = lookup_one_len(XAROOT_NAME, privroot, strlen(XAROOT_NAME)); 103 if (IS_ERR(xaroot)) { 104 goto out; 105 } else if (!xaroot->d_inode) { 106 dput(xaroot); 107 xaroot = NULL; 108 goto out; 109 } 110 111 REISERFS_SB(s)->xattr_root = dget(xaroot); 112 113 out: 114 dput(privroot); 115 return xaroot; 116 } 117 118 /* Returns the dentry (or NULL) referring to the root of the extended 119 * attribute directory tree. If it has already been retrieved, it is used. 120 * Otherwise, we attempt to retrieve it from disk. It may also return 121 * a pointer-encoded error. 122 */ 123 static inline struct dentry *get_xa_root(struct super_block *s) 124 { 125 struct dentry *dentry = dget(REISERFS_SB(s)->xattr_root); 126 127 if (!dentry) 128 dentry = __get_xa_root(s); 129 130 return dentry; 131 } 132 133 /* Opens the directory corresponding to the inode's extended attribute store. 134 * If flags allow, the tree to the directory may be created. If creation is 135 * prohibited, -ENODATA is returned. */ 136 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 137 { 138 struct dentry *xaroot, *xadir; 139 char namebuf[17]; 140 141 xaroot = get_xa_root(inode->i_sb); 142 if (IS_ERR(xaroot)) { 143 return xaroot; 144 } else if (!xaroot) { 145 if (flags == 0 || flags & XATTR_CREATE) { 146 xaroot = create_xa_root(inode->i_sb); 147 if (IS_ERR(xaroot)) 148 return xaroot; 149 } 150 if (!xaroot) 151 return ERR_PTR(-ENODATA); 152 } 153 154 /* ok, we have xaroot open */ 155 156 snprintf(namebuf, sizeof(namebuf), "%X.%X", 157 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 158 inode->i_generation); 159 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); 160 if (IS_ERR(xadir)) { 161 dput(xaroot); 162 return xadir; 163 } 164 165 if (!xadir->d_inode) { 166 int err; 167 if (flags == 0 || flags & XATTR_CREATE) { 168 /* Although there is nothing else trying to create this directory, 169 * another directory with the same hash may be created, so we need 170 * to protect against that */ 171 err = 172 xaroot->d_inode->i_op->mkdir(xaroot->d_inode, xadir, 173 0700); 174 if (err) { 175 dput(xaroot); 176 dput(xadir); 177 return ERR_PTR(err); 178 } 179 } 180 if (!xadir->d_inode) { 181 dput(xaroot); 182 dput(xadir); 183 return ERR_PTR(-ENODATA); 184 } 185 } 186 187 dput(xaroot); 188 return xadir; 189 } 190 191 /* Returns a dentry corresponding to a specific extended attribute file 192 * for the inode. If flags allow, the file is created. Otherwise, a 193 * valid or negative dentry, or an error is returned. */ 194 static struct dentry *get_xa_file_dentry(const struct inode *inode, 195 const char *name, int flags) 196 { 197 struct dentry *xadir, *xafile; 198 int err = 0; 199 200 xadir = open_xa_dir(inode, flags); 201 if (IS_ERR(xadir)) { 202 return ERR_PTR(PTR_ERR(xadir)); 203 } else if (xadir && !xadir->d_inode) { 204 dput(xadir); 205 return ERR_PTR(-ENODATA); 206 } 207 208 xafile = lookup_one_len(name, xadir, strlen(name)); 209 if (IS_ERR(xafile)) { 210 dput(xadir); 211 return ERR_PTR(PTR_ERR(xafile)); 212 } 213 214 if (xafile->d_inode) { /* file exists */ 215 if (flags & XATTR_CREATE) { 216 err = -EEXIST; 217 dput(xafile); 218 goto out; 219 } 220 } else if (flags & XATTR_REPLACE || flags & FL_READONLY) { 221 goto out; 222 } else { 223 /* inode->i_mutex is down, so nothing else can try to create 224 * the same xattr */ 225 err = xadir->d_inode->i_op->create(xadir->d_inode, xafile, 226 0700 | S_IFREG, NULL); 227 228 if (err) { 229 dput(xafile); 230 goto out; 231 } 232 } 233 234 out: 235 dput(xadir); 236 if (err) 237 xafile = ERR_PTR(err); 238 return xafile; 239 } 240 241 /* Opens a file pointer to the attribute associated with inode */ 242 static struct file *open_xa_file(const struct inode *inode, const char *name, 243 int flags) 244 { 245 struct dentry *xafile; 246 struct file *fp; 247 248 xafile = get_xa_file_dentry(inode, name, flags); 249 if (IS_ERR(xafile)) 250 return ERR_PTR(PTR_ERR(xafile)); 251 else if (!xafile->d_inode) { 252 dput(xafile); 253 return ERR_PTR(-ENODATA); 254 } 255 256 fp = dentry_open(xafile, NULL, O_RDWR); 257 /* dentry_open dputs the dentry if it fails */ 258 259 return fp; 260 } 261 262 /* 263 * this is very similar to fs/reiserfs/dir.c:reiserfs_readdir, but 264 * we need to drop the path before calling the filldir struct. That 265 * would be a big performance hit to the non-xattr case, so I've copied 266 * the whole thing for now. --clm 267 * 268 * the big difference is that I go backwards through the directory, 269 * and don't mess with f->f_pos, but the idea is the same. Do some 270 * action on each and every entry in the directory. 271 * 272 * we're called with i_mutex held, so there are no worries about the directory 273 * changing underneath us. 274 */ 275 static int __xattr_readdir(struct file *filp, void *dirent, filldir_t filldir) 276 { 277 struct inode *inode = filp->f_dentry->d_inode; 278 struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */ 279 INITIALIZE_PATH(path_to_entry); 280 struct buffer_head *bh; 281 int entry_num; 282 struct item_head *ih, tmp_ih; 283 int search_res; 284 char *local_buf; 285 loff_t next_pos; 286 char small_buf[32]; /* avoid kmalloc if we can */ 287 struct reiserfs_de_head *deh; 288 int d_reclen; 289 char *d_name; 290 off_t d_off; 291 ino_t d_ino; 292 struct reiserfs_dir_entry de; 293 294 /* form key for search the next directory entry using f_pos field of 295 file structure */ 296 next_pos = max_reiserfs_offset(inode); 297 298 while (1) { 299 research: 300 if (next_pos <= DOT_DOT_OFFSET) 301 break; 302 make_cpu_key(&pos_key, inode, next_pos, TYPE_DIRENTRY, 3); 303 304 search_res = 305 search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry, 306 &de); 307 if (search_res == IO_ERROR) { 308 // FIXME: we could just skip part of directory which could 309 // not be read 310 pathrelse(&path_to_entry); 311 return -EIO; 312 } 313 314 if (search_res == NAME_NOT_FOUND) 315 de.de_entry_num--; 316 317 set_de_name_and_namelen(&de); 318 entry_num = de.de_entry_num; 319 deh = &(de.de_deh[entry_num]); 320 321 bh = de.de_bh; 322 ih = de.de_ih; 323 324 if (!is_direntry_le_ih(ih)) { 325 reiserfs_warning(inode->i_sb, "not direntry %h", ih); 326 break; 327 } 328 copy_item_head(&tmp_ih, ih); 329 330 /* we must have found item, that is item of this directory, */ 331 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key), 332 "vs-9000: found item %h does not match to dir we readdir %K", 333 ih, &pos_key); 334 335 if (deh_offset(deh) <= DOT_DOT_OFFSET) { 336 break; 337 } 338 339 /* look for the previous entry in the directory */ 340 next_pos = deh_offset(deh) - 1; 341 342 if (!de_visible(deh)) 343 /* it is hidden entry */ 344 continue; 345 346 d_reclen = entry_length(bh, ih, entry_num); 347 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh); 348 d_off = deh_offset(deh); 349 d_ino = deh_objectid(deh); 350 351 if (!d_name[d_reclen - 1]) 352 d_reclen = strlen(d_name); 353 354 if (d_reclen > REISERFS_MAX_NAME(inode->i_sb->s_blocksize)) { 355 /* too big to send back to VFS */ 356 continue; 357 } 358 359 /* Ignore the .reiserfs_priv entry */ 360 if (reiserfs_xattrs(inode->i_sb) && 361 !old_format_only(inode->i_sb) && 362 deh_objectid(deh) == 363 le32_to_cpu(INODE_PKEY 364 (REISERFS_SB(inode->i_sb)->priv_root->d_inode)-> 365 k_objectid)) 366 continue; 367 368 if (d_reclen <= 32) { 369 local_buf = small_buf; 370 } else { 371 local_buf = kmalloc(d_reclen, GFP_NOFS); 372 if (!local_buf) { 373 pathrelse(&path_to_entry); 374 return -ENOMEM; 375 } 376 if (item_moved(&tmp_ih, &path_to_entry)) { 377 kfree(local_buf); 378 379 /* sigh, must retry. Do this same offset again */ 380 next_pos = d_off; 381 goto research; 382 } 383 } 384 385 // Note, that we copy name to user space via temporary 386 // buffer (local_buf) because filldir will block if 387 // user space buffer is swapped out. At that time 388 // entry can move to somewhere else 389 memcpy(local_buf, d_name, d_reclen); 390 391 /* the filldir function might need to start transactions, 392 * or do who knows what. Release the path now that we've 393 * copied all the important stuff out of the deh 394 */ 395 pathrelse(&path_to_entry); 396 397 if (filldir(dirent, local_buf, d_reclen, d_off, d_ino, 398 DT_UNKNOWN) < 0) { 399 if (local_buf != small_buf) { 400 kfree(local_buf); 401 } 402 goto end; 403 } 404 if (local_buf != small_buf) { 405 kfree(local_buf); 406 } 407 } /* while */ 408 409 end: 410 pathrelse(&path_to_entry); 411 return 0; 412 } 413 414 /* 415 * this could be done with dedicated readdir ops for the xattr files, 416 * but I want to get something working asap 417 * this is stolen from vfs_readdir 418 * 419 */ 420 static 421 int xattr_readdir(struct file *file, filldir_t filler, void *buf) 422 { 423 struct inode *inode = file->f_dentry->d_inode; 424 int res = -ENOTDIR; 425 if (!file->f_op || !file->f_op->readdir) 426 goto out; 427 mutex_lock_nested(&inode->i_mutex, I_MUTEX_XATTR); 428 // down(&inode->i_zombie); 429 res = -ENOENT; 430 if (!IS_DEADDIR(inode)) { 431 lock_kernel(); 432 res = __xattr_readdir(file, buf, filler); 433 unlock_kernel(); 434 } 435 // up(&inode->i_zombie); 436 mutex_unlock(&inode->i_mutex); 437 out: 438 return res; 439 } 440 441 /* Internal operations on file data */ 442 static inline void reiserfs_put_page(struct page *page) 443 { 444 kunmap(page); 445 page_cache_release(page); 446 } 447 448 static struct page *reiserfs_get_page(struct inode *dir, unsigned long n) 449 { 450 struct address_space *mapping = dir->i_mapping; 451 struct page *page; 452 /* We can deadlock if we try to free dentries, 453 and an unlink/rmdir has just occured - GFP_NOFS avoids this */ 454 mapping_set_gfp_mask(mapping, GFP_NOFS); 455 page = read_mapping_page(mapping, n, NULL); 456 if (!IS_ERR(page)) { 457 wait_on_page_locked(page); 458 kmap(page); 459 if (!PageUptodate(page)) 460 goto fail; 461 462 if (PageError(page)) 463 goto fail; 464 } 465 return page; 466 467 fail: 468 reiserfs_put_page(page); 469 return ERR_PTR(-EIO); 470 } 471 472 static inline __u32 xattr_hash(const char *msg, int len) 473 { 474 return csum_partial(msg, len, 0); 475 } 476 477 /* Generic extended attribute operations that can be used by xa plugins */ 478 479 /* 480 * inode->i_mutex: down 481 */ 482 int 483 reiserfs_xattr_set(struct inode *inode, const char *name, const void *buffer, 484 size_t buffer_size, int flags) 485 { 486 int err = 0; 487 struct file *fp; 488 struct page *page; 489 char *data; 490 struct address_space *mapping; 491 size_t file_pos = 0; 492 size_t buffer_pos = 0; 493 struct inode *xinode; 494 struct iattr newattrs; 495 __u32 xahash = 0; 496 497 if (get_inode_sd_version(inode) == STAT_DATA_V1) 498 return -EOPNOTSUPP; 499 500 /* Empty xattrs are ok, they're just empty files, no hash */ 501 if (buffer && buffer_size) 502 xahash = xattr_hash(buffer, buffer_size); 503 504 open_file: 505 fp = open_xa_file(inode, name, flags); 506 if (IS_ERR(fp)) { 507 err = PTR_ERR(fp); 508 goto out; 509 } 510 511 xinode = fp->f_dentry->d_inode; 512 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 513 514 /* we need to copy it off.. */ 515 if (xinode->i_nlink > 1) { 516 fput(fp); 517 err = reiserfs_xattr_del(inode, name); 518 if (err < 0) 519 goto out; 520 /* We just killed the old one, we're not replacing anymore */ 521 if (flags & XATTR_REPLACE) 522 flags &= ~XATTR_REPLACE; 523 goto open_file; 524 } 525 526 /* Resize it so we're ok to write there */ 527 newattrs.ia_size = buffer_size; 528 newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; 529 mutex_lock(&xinode->i_mutex); 530 err = notify_change(fp->f_dentry, &newattrs); 531 if (err) 532 goto out_filp; 533 534 mapping = xinode->i_mapping; 535 while (buffer_pos < buffer_size || buffer_pos == 0) { 536 size_t chunk; 537 size_t skip = 0; 538 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 539 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 540 chunk = PAGE_CACHE_SIZE; 541 else 542 chunk = buffer_size - buffer_pos; 543 544 page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT); 545 if (IS_ERR(page)) { 546 err = PTR_ERR(page); 547 goto out_filp; 548 } 549 550 lock_page(page); 551 data = page_address(page); 552 553 if (file_pos == 0) { 554 struct reiserfs_xattr_header *rxh; 555 skip = file_pos = sizeof(struct reiserfs_xattr_header); 556 if (chunk + skip > PAGE_CACHE_SIZE) 557 chunk = PAGE_CACHE_SIZE - skip; 558 rxh = (struct reiserfs_xattr_header *)data; 559 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 560 rxh->h_hash = cpu_to_le32(xahash); 561 } 562 563 err = mapping->a_ops->prepare_write(fp, page, page_offset, 564 page_offset + chunk + skip); 565 if (!err) { 566 if (buffer) 567 memcpy(data + skip, buffer + buffer_pos, chunk); 568 err = 569 mapping->a_ops->commit_write(fp, page, page_offset, 570 page_offset + chunk + 571 skip); 572 } 573 unlock_page(page); 574 reiserfs_put_page(page); 575 buffer_pos += chunk; 576 file_pos += chunk; 577 skip = 0; 578 if (err || buffer_size == 0 || !buffer) 579 break; 580 } 581 582 /* We can't mark the inode dirty if it's not hashed. This is the case 583 * when we're inheriting the default ACL. If we dirty it, the inode 584 * gets marked dirty, but won't (ever) make it onto the dirty list until 585 * it's synced explicitly to clear I_DIRTY. This is bad. */ 586 if (!hlist_unhashed(&inode->i_hash)) { 587 inode->i_ctime = CURRENT_TIME_SEC; 588 mark_inode_dirty(inode); 589 } 590 591 out_filp: 592 mutex_unlock(&xinode->i_mutex); 593 fput(fp); 594 595 out: 596 return err; 597 } 598 599 /* 600 * inode->i_mutex: down 601 */ 602 int 603 reiserfs_xattr_get(const struct inode *inode, const char *name, void *buffer, 604 size_t buffer_size) 605 { 606 ssize_t err = 0; 607 struct file *fp; 608 size_t isize; 609 size_t file_pos = 0; 610 size_t buffer_pos = 0; 611 struct page *page; 612 struct inode *xinode; 613 __u32 hash = 0; 614 615 if (name == NULL) 616 return -EINVAL; 617 618 /* We can't have xattrs attached to v1 items since they don't have 619 * generation numbers */ 620 if (get_inode_sd_version(inode) == STAT_DATA_V1) 621 return -EOPNOTSUPP; 622 623 fp = open_xa_file(inode, name, FL_READONLY); 624 if (IS_ERR(fp)) { 625 err = PTR_ERR(fp); 626 goto out; 627 } 628 629 xinode = fp->f_dentry->d_inode; 630 isize = xinode->i_size; 631 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 632 633 /* Just return the size needed */ 634 if (buffer == NULL) { 635 err = isize - sizeof(struct reiserfs_xattr_header); 636 goto out_dput; 637 } 638 639 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 640 err = -ERANGE; 641 goto out_dput; 642 } 643 644 while (file_pos < isize) { 645 size_t chunk; 646 char *data; 647 size_t skip = 0; 648 if (isize - file_pos > PAGE_CACHE_SIZE) 649 chunk = PAGE_CACHE_SIZE; 650 else 651 chunk = isize - file_pos; 652 653 page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT); 654 if (IS_ERR(page)) { 655 err = PTR_ERR(page); 656 goto out_dput; 657 } 658 659 lock_page(page); 660 data = page_address(page); 661 if (file_pos == 0) { 662 struct reiserfs_xattr_header *rxh = 663 (struct reiserfs_xattr_header *)data; 664 skip = file_pos = sizeof(struct reiserfs_xattr_header); 665 chunk -= skip; 666 /* Magic doesn't match up.. */ 667 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 668 unlock_page(page); 669 reiserfs_put_page(page); 670 reiserfs_warning(inode->i_sb, 671 "Invalid magic for xattr (%s) " 672 "associated with %k", name, 673 INODE_PKEY(inode)); 674 err = -EIO; 675 goto out_dput; 676 } 677 hash = le32_to_cpu(rxh->h_hash); 678 } 679 memcpy(buffer + buffer_pos, data + skip, chunk); 680 unlock_page(page); 681 reiserfs_put_page(page); 682 file_pos += chunk; 683 buffer_pos += chunk; 684 skip = 0; 685 } 686 err = isize - sizeof(struct reiserfs_xattr_header); 687 688 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 689 hash) { 690 reiserfs_warning(inode->i_sb, 691 "Invalid hash for xattr (%s) associated " 692 "with %k", name, INODE_PKEY(inode)); 693 err = -EIO; 694 } 695 696 out_dput: 697 fput(fp); 698 699 out: 700 return err; 701 } 702 703 static int 704 __reiserfs_xattr_del(struct dentry *xadir, const char *name, int namelen) 705 { 706 struct dentry *dentry; 707 struct inode *dir = xadir->d_inode; 708 int err = 0; 709 710 dentry = lookup_one_len(name, xadir, namelen); 711 if (IS_ERR(dentry)) { 712 err = PTR_ERR(dentry); 713 goto out; 714 } else if (!dentry->d_inode) { 715 err = -ENODATA; 716 goto out_file; 717 } 718 719 /* Skip directories.. */ 720 if (S_ISDIR(dentry->d_inode->i_mode)) 721 goto out_file; 722 723 if (!is_reiserfs_priv_object(dentry->d_inode)) { 724 reiserfs_warning(dir->i_sb, "OID %08x [%.*s/%.*s] doesn't have " 725 "priv flag set [parent is %sset].", 726 le32_to_cpu(INODE_PKEY(dentry->d_inode)-> 727 k_objectid), xadir->d_name.len, 728 xadir->d_name.name, namelen, name, 729 is_reiserfs_priv_object(xadir-> 730 d_inode) ? "" : 731 "not "); 732 dput(dentry); 733 return -EIO; 734 } 735 736 err = dir->i_op->unlink(dir, dentry); 737 if (!err) 738 d_delete(dentry); 739 740 out_file: 741 dput(dentry); 742 743 out: 744 return err; 745 } 746 747 int reiserfs_xattr_del(struct inode *inode, const char *name) 748 { 749 struct dentry *dir; 750 int err; 751 752 dir = open_xa_dir(inode, FL_READONLY); 753 if (IS_ERR(dir)) { 754 err = PTR_ERR(dir); 755 goto out; 756 } 757 758 err = __reiserfs_xattr_del(dir, name, strlen(name)); 759 dput(dir); 760 761 if (!err) { 762 inode->i_ctime = CURRENT_TIME_SEC; 763 mark_inode_dirty(inode); 764 } 765 766 out: 767 return err; 768 } 769 770 /* The following are side effects of other operations that aren't explicitly 771 * modifying extended attributes. This includes operations such as permissions 772 * or ownership changes, object deletions, etc. */ 773 774 static int 775 reiserfs_delete_xattrs_filler(void *buf, const char *name, int namelen, 776 loff_t offset, u64 ino, unsigned int d_type) 777 { 778 struct dentry *xadir = (struct dentry *)buf; 779 780 return __reiserfs_xattr_del(xadir, name, namelen); 781 782 } 783 784 /* This is called w/ inode->i_mutex downed */ 785 int reiserfs_delete_xattrs(struct inode *inode) 786 { 787 struct file *fp; 788 struct dentry *dir, *root; 789 int err = 0; 790 791 /* Skip out, an xattr has no xattrs associated with it */ 792 if (is_reiserfs_priv_object(inode) || 793 get_inode_sd_version(inode) == STAT_DATA_V1 || 794 !reiserfs_xattrs(inode->i_sb)) { 795 return 0; 796 } 797 reiserfs_read_lock_xattrs(inode->i_sb); 798 dir = open_xa_dir(inode, FL_READONLY); 799 reiserfs_read_unlock_xattrs(inode->i_sb); 800 if (IS_ERR(dir)) { 801 err = PTR_ERR(dir); 802 goto out; 803 } else if (!dir->d_inode) { 804 dput(dir); 805 return 0; 806 } 807 808 fp = dentry_open(dir, NULL, O_RDWR); 809 if (IS_ERR(fp)) { 810 err = PTR_ERR(fp); 811 /* dentry_open dputs the dentry if it fails */ 812 goto out; 813 } 814 815 lock_kernel(); 816 err = xattr_readdir(fp, reiserfs_delete_xattrs_filler, dir); 817 if (err) { 818 unlock_kernel(); 819 goto out_dir; 820 } 821 822 /* Leftovers besides . and .. -- that's not good. */ 823 if (dir->d_inode->i_nlink <= 2) { 824 root = get_xa_root(inode->i_sb); 825 reiserfs_write_lock_xattrs(inode->i_sb); 826 err = vfs_rmdir(root->d_inode, dir); 827 reiserfs_write_unlock_xattrs(inode->i_sb); 828 dput(root); 829 } else { 830 reiserfs_warning(inode->i_sb, 831 "Couldn't remove all entries in directory"); 832 } 833 unlock_kernel(); 834 835 out_dir: 836 fput(fp); 837 838 out: 839 if (!err) 840 REISERFS_I(inode)->i_flags = 841 REISERFS_I(inode)->i_flags & ~i_has_xattr_dir; 842 return err; 843 } 844 845 struct reiserfs_chown_buf { 846 struct inode *inode; 847 struct dentry *xadir; 848 struct iattr *attrs; 849 }; 850 851 /* XXX: If there is a better way to do this, I'd love to hear about it */ 852 static int 853 reiserfs_chown_xattrs_filler(void *buf, const char *name, int namelen, 854 loff_t offset, u64 ino, unsigned int d_type) 855 { 856 struct reiserfs_chown_buf *chown_buf = (struct reiserfs_chown_buf *)buf; 857 struct dentry *xafile, *xadir = chown_buf->xadir; 858 struct iattr *attrs = chown_buf->attrs; 859 int err = 0; 860 861 xafile = lookup_one_len(name, xadir, namelen); 862 if (IS_ERR(xafile)) 863 return PTR_ERR(xafile); 864 else if (!xafile->d_inode) { 865 dput(xafile); 866 return -ENODATA; 867 } 868 869 if (!S_ISDIR(xafile->d_inode->i_mode)) 870 err = notify_change(xafile, attrs); 871 dput(xafile); 872 873 return err; 874 } 875 876 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 877 { 878 struct file *fp; 879 struct dentry *dir; 880 int err = 0; 881 struct reiserfs_chown_buf buf; 882 unsigned int ia_valid = attrs->ia_valid; 883 884 /* Skip out, an xattr has no xattrs associated with it */ 885 if (is_reiserfs_priv_object(inode) || 886 get_inode_sd_version(inode) == STAT_DATA_V1 || 887 !reiserfs_xattrs(inode->i_sb)) { 888 return 0; 889 } 890 reiserfs_read_lock_xattrs(inode->i_sb); 891 dir = open_xa_dir(inode, FL_READONLY); 892 reiserfs_read_unlock_xattrs(inode->i_sb); 893 if (IS_ERR(dir)) { 894 if (PTR_ERR(dir) != -ENODATA) 895 err = PTR_ERR(dir); 896 goto out; 897 } else if (!dir->d_inode) { 898 dput(dir); 899 goto out; 900 } 901 902 fp = dentry_open(dir, NULL, O_RDWR); 903 if (IS_ERR(fp)) { 904 err = PTR_ERR(fp); 905 /* dentry_open dputs the dentry if it fails */ 906 goto out; 907 } 908 909 lock_kernel(); 910 911 attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME); 912 buf.xadir = dir; 913 buf.attrs = attrs; 914 buf.inode = inode; 915 916 err = xattr_readdir(fp, reiserfs_chown_xattrs_filler, &buf); 917 if (err) { 918 unlock_kernel(); 919 goto out_dir; 920 } 921 922 err = notify_change(dir, attrs); 923 unlock_kernel(); 924 925 out_dir: 926 fput(fp); 927 928 out: 929 attrs->ia_valid = ia_valid; 930 return err; 931 } 932 933 /* Actual operations that are exported to VFS-land */ 934 935 /* 936 * Inode operation getxattr() 937 * Preliminary locking: we down dentry->d_inode->i_mutex 938 */ 939 ssize_t 940 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 941 size_t size) 942 { 943 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 944 int err; 945 946 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 947 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 948 return -EOPNOTSUPP; 949 950 reiserfs_read_lock_xattr_i(dentry->d_inode); 951 reiserfs_read_lock_xattrs(dentry->d_sb); 952 err = xah->get(dentry->d_inode, name, buffer, size); 953 reiserfs_read_unlock_xattrs(dentry->d_sb); 954 reiserfs_read_unlock_xattr_i(dentry->d_inode); 955 return err; 956 } 957 958 /* 959 * Inode operation setxattr() 960 * 961 * dentry->d_inode->i_mutex down 962 */ 963 int 964 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 965 size_t size, int flags) 966 { 967 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 968 int err; 969 int lock; 970 971 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 972 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 973 return -EOPNOTSUPP; 974 975 reiserfs_write_lock_xattr_i(dentry->d_inode); 976 lock = !has_xattr_dir(dentry->d_inode); 977 if (lock) 978 reiserfs_write_lock_xattrs(dentry->d_sb); 979 else 980 reiserfs_read_lock_xattrs(dentry->d_sb); 981 err = xah->set(dentry->d_inode, name, value, size, flags); 982 if (lock) 983 reiserfs_write_unlock_xattrs(dentry->d_sb); 984 else 985 reiserfs_read_unlock_xattrs(dentry->d_sb); 986 reiserfs_write_unlock_xattr_i(dentry->d_inode); 987 return err; 988 } 989 990 /* 991 * Inode operation removexattr() 992 * 993 * dentry->d_inode->i_mutex down 994 */ 995 int reiserfs_removexattr(struct dentry *dentry, const char *name) 996 { 997 int err; 998 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 999 1000 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 1001 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 1002 return -EOPNOTSUPP; 1003 1004 reiserfs_write_lock_xattr_i(dentry->d_inode); 1005 reiserfs_read_lock_xattrs(dentry->d_sb); 1006 1007 /* Deletion pre-operation */ 1008 if (xah->del) { 1009 err = xah->del(dentry->d_inode, name); 1010 if (err) 1011 goto out; 1012 } 1013 1014 err = reiserfs_xattr_del(dentry->d_inode, name); 1015 1016 dentry->d_inode->i_ctime = CURRENT_TIME_SEC; 1017 mark_inode_dirty(dentry->d_inode); 1018 1019 out: 1020 reiserfs_read_unlock_xattrs(dentry->d_sb); 1021 reiserfs_write_unlock_xattr_i(dentry->d_inode); 1022 return err; 1023 } 1024 1025 /* This is what filldir will use: 1026 * r_pos will always contain the amount of space required for the entire 1027 * list. If r_pos becomes larger than r_size, we need more space and we 1028 * return an error indicating this. If r_pos is less than r_size, then we've 1029 * filled the buffer successfully and we return success */ 1030 struct reiserfs_listxattr_buf { 1031 int r_pos; 1032 int r_size; 1033 char *r_buf; 1034 struct inode *r_inode; 1035 }; 1036 1037 static int 1038 reiserfs_listxattr_filler(void *buf, const char *name, int namelen, 1039 loff_t offset, u64 ino, unsigned int d_type) 1040 { 1041 struct reiserfs_listxattr_buf *b = (struct reiserfs_listxattr_buf *)buf; 1042 int len = 0; 1043 if (name[0] != '.' 1044 || (namelen != 1 && (name[1] != '.' || namelen != 2))) { 1045 struct reiserfs_xattr_handler *xah = 1046 find_xattr_handler_prefix(name); 1047 if (!xah) 1048 return 0; /* Unsupported xattr name, skip it */ 1049 1050 /* We call ->list() twice because the operation isn't required to just 1051 * return the name back - we want to make sure we have enough space */ 1052 len += xah->list(b->r_inode, name, namelen, NULL); 1053 1054 if (len) { 1055 if (b->r_pos + len + 1 <= b->r_size) { 1056 char *p = b->r_buf + b->r_pos; 1057 p += xah->list(b->r_inode, name, namelen, p); 1058 *p++ = '\0'; 1059 } 1060 b->r_pos += len + 1; 1061 } 1062 } 1063 1064 return 0; 1065 } 1066 1067 /* 1068 * Inode operation listxattr() 1069 * 1070 * Preliminary locking: we down dentry->d_inode->i_mutex 1071 */ 1072 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 1073 { 1074 struct file *fp; 1075 struct dentry *dir; 1076 int err = 0; 1077 struct reiserfs_listxattr_buf buf; 1078 1079 if (!dentry->d_inode) 1080 return -EINVAL; 1081 1082 if (!reiserfs_xattrs(dentry->d_sb) || 1083 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 1084 return -EOPNOTSUPP; 1085 1086 reiserfs_read_lock_xattr_i(dentry->d_inode); 1087 reiserfs_read_lock_xattrs(dentry->d_sb); 1088 dir = open_xa_dir(dentry->d_inode, FL_READONLY); 1089 reiserfs_read_unlock_xattrs(dentry->d_sb); 1090 if (IS_ERR(dir)) { 1091 err = PTR_ERR(dir); 1092 if (err == -ENODATA) 1093 err = 0; /* Not an error if there aren't any xattrs */ 1094 goto out; 1095 } 1096 1097 fp = dentry_open(dir, NULL, O_RDWR); 1098 if (IS_ERR(fp)) { 1099 err = PTR_ERR(fp); 1100 /* dentry_open dputs the dentry if it fails */ 1101 goto out; 1102 } 1103 1104 buf.r_buf = buffer; 1105 buf.r_size = buffer ? size : 0; 1106 buf.r_pos = 0; 1107 buf.r_inode = dentry->d_inode; 1108 1109 REISERFS_I(dentry->d_inode)->i_flags |= i_has_xattr_dir; 1110 1111 err = xattr_readdir(fp, reiserfs_listxattr_filler, &buf); 1112 if (err) 1113 goto out_dir; 1114 1115 if (buf.r_pos > buf.r_size && buffer != NULL) 1116 err = -ERANGE; 1117 else 1118 err = buf.r_pos; 1119 1120 out_dir: 1121 fput(fp); 1122 1123 out: 1124 reiserfs_read_unlock_xattr_i(dentry->d_inode); 1125 return err; 1126 } 1127 1128 /* This is the implementation for the xattr plugin infrastructure */ 1129 static struct list_head xattr_handlers = LIST_HEAD_INIT(xattr_handlers); 1130 static DEFINE_RWLOCK(handler_lock); 1131 1132 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char 1133 *prefix) 1134 { 1135 struct reiserfs_xattr_handler *xah = NULL; 1136 struct list_head *p; 1137 1138 read_lock(&handler_lock); 1139 list_for_each(p, &xattr_handlers) { 1140 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1141 if (strncmp(xah->prefix, prefix, strlen(xah->prefix)) == 0) 1142 break; 1143 xah = NULL; 1144 } 1145 1146 read_unlock(&handler_lock); 1147 return xah; 1148 } 1149 1150 static void __unregister_handlers(void) 1151 { 1152 struct reiserfs_xattr_handler *xah; 1153 struct list_head *p, *tmp; 1154 1155 list_for_each_safe(p, tmp, &xattr_handlers) { 1156 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1157 if (xah->exit) 1158 xah->exit(); 1159 1160 list_del_init(p); 1161 } 1162 INIT_LIST_HEAD(&xattr_handlers); 1163 } 1164 1165 int __init reiserfs_xattr_register_handlers(void) 1166 { 1167 int err = 0; 1168 struct reiserfs_xattr_handler *xah; 1169 struct list_head *p; 1170 1171 write_lock(&handler_lock); 1172 1173 /* If we're already initialized, nothing to do */ 1174 if (!list_empty(&xattr_handlers)) { 1175 write_unlock(&handler_lock); 1176 return 0; 1177 } 1178 1179 /* Add the handlers */ 1180 list_add_tail(&user_handler.handlers, &xattr_handlers); 1181 list_add_tail(&trusted_handler.handlers, &xattr_handlers); 1182 #ifdef CONFIG_REISERFS_FS_SECURITY 1183 list_add_tail(&security_handler.handlers, &xattr_handlers); 1184 #endif 1185 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 1186 list_add_tail(&posix_acl_access_handler.handlers, &xattr_handlers); 1187 list_add_tail(&posix_acl_default_handler.handlers, &xattr_handlers); 1188 #endif 1189 1190 /* Run initializers, if available */ 1191 list_for_each(p, &xattr_handlers) { 1192 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1193 if (xah->init) { 1194 err = xah->init(); 1195 if (err) { 1196 list_del_init(p); 1197 break; 1198 } 1199 } 1200 } 1201 1202 /* Clean up other handlers, if any failed */ 1203 if (err) 1204 __unregister_handlers(); 1205 1206 write_unlock(&handler_lock); 1207 return err; 1208 } 1209 1210 void reiserfs_xattr_unregister_handlers(void) 1211 { 1212 write_lock(&handler_lock); 1213 __unregister_handlers(); 1214 write_unlock(&handler_lock); 1215 } 1216 1217 /* This will catch lookups from the fs root to .reiserfs_priv */ 1218 static int 1219 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 1220 { 1221 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 1222 if (name->len == priv_root->d_name.len && 1223 name->hash == priv_root->d_name.hash && 1224 !memcmp(name->name, priv_root->d_name.name, name->len)) { 1225 return -ENOENT; 1226 } else if (q1->len == name->len && 1227 !memcmp(q1->name, name->name, name->len)) 1228 return 0; 1229 return 1; 1230 } 1231 1232 static struct dentry_operations xattr_lookup_poison_ops = { 1233 .d_compare = xattr_lookup_poison, 1234 }; 1235 1236 /* We need to take a copy of the mount flags since things like 1237 * MS_RDONLY don't get set until *after* we're called. 1238 * mount_flags != mount_options */ 1239 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1240 { 1241 int err = 0; 1242 1243 /* We need generation numbers to ensure that the oid mapping is correct 1244 * v3.5 filesystems don't have them. */ 1245 if (!old_format_only(s)) { 1246 set_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1247 } else if (reiserfs_xattrs_optional(s)) { 1248 /* Old format filesystem, but optional xattrs have been enabled 1249 * at mount time. Error out. */ 1250 reiserfs_warning(s, "xattrs/ACLs not supported on pre v3.6 " 1251 "format filesystem. Failing mount."); 1252 err = -EOPNOTSUPP; 1253 goto error; 1254 } else { 1255 /* Old format filesystem, but no optional xattrs have been enabled. This 1256 * means we silently disable xattrs on the filesystem. */ 1257 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1258 } 1259 1260 /* If we don't have the privroot located yet - go find it */ 1261 if (reiserfs_xattrs(s) && !REISERFS_SB(s)->priv_root) { 1262 struct dentry *dentry; 1263 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 1264 strlen(PRIVROOT_NAME)); 1265 if (!IS_ERR(dentry)) { 1266 if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) { 1267 struct inode *inode = dentry->d_parent->d_inode; 1268 mutex_lock(&inode->i_mutex); 1269 err = inode->i_op->mkdir(inode, dentry, 0700); 1270 mutex_unlock(&inode->i_mutex); 1271 if (err) { 1272 dput(dentry); 1273 dentry = NULL; 1274 } 1275 1276 if (dentry && dentry->d_inode) 1277 reiserfs_warning(s, 1278 "Created %s on %s - reserved for " 1279 "xattr storage.", 1280 PRIVROOT_NAME, 1281 reiserfs_bdevname 1282 (inode->i_sb)); 1283 } else if (!dentry->d_inode) { 1284 dput(dentry); 1285 dentry = NULL; 1286 } 1287 } else 1288 err = PTR_ERR(dentry); 1289 1290 if (!err && dentry) { 1291 s->s_root->d_op = &xattr_lookup_poison_ops; 1292 reiserfs_mark_inode_private(dentry->d_inode); 1293 REISERFS_SB(s)->priv_root = dentry; 1294 } else if (!(mount_flags & MS_RDONLY)) { /* xattrs are unavailable */ 1295 /* If we're read-only it just means that the dir hasn't been 1296 * created. Not an error -- just no xattrs on the fs. We'll 1297 * check again if we go read-write */ 1298 reiserfs_warning(s, "xattrs/ACLs enabled and couldn't " 1299 "find/create .reiserfs_priv. Failing mount."); 1300 err = -EOPNOTSUPP; 1301 } 1302 } 1303 1304 error: 1305 /* This is only nonzero if there was an error initializing the xattr 1306 * directory or if there is a condition where we don't support them. */ 1307 if (err) { 1308 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1309 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1310 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1311 } 1312 1313 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1314 s->s_flags = s->s_flags & ~MS_POSIXACL; 1315 if (reiserfs_posixacl(s)) 1316 s->s_flags |= MS_POSIXACL; 1317 1318 return err; 1319 } 1320 1321 static int reiserfs_check_acl(struct inode *inode, int mask) 1322 { 1323 struct posix_acl *acl; 1324 int error = -EAGAIN; /* do regular unix permission checks by default */ 1325 1326 reiserfs_read_lock_xattr_i(inode); 1327 reiserfs_read_lock_xattrs(inode->i_sb); 1328 1329 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 1330 1331 reiserfs_read_unlock_xattrs(inode->i_sb); 1332 reiserfs_read_unlock_xattr_i(inode); 1333 1334 if (acl) { 1335 if (!IS_ERR(acl)) { 1336 error = posix_acl_permission(inode, acl, mask); 1337 posix_acl_release(acl); 1338 } else if (PTR_ERR(acl) != -ENODATA) 1339 error = PTR_ERR(acl); 1340 } 1341 1342 return error; 1343 } 1344 1345 int reiserfs_permission(struct inode *inode, int mask, struct nameidata *nd) 1346 { 1347 /* 1348 * We don't do permission checks on the internal objects. 1349 * Permissions are determined by the "owning" object. 1350 */ 1351 if (is_reiserfs_priv_object(inode)) 1352 return 0; 1353 1354 /* 1355 * Stat data v1 doesn't support ACLs. 1356 */ 1357 if (get_inode_sd_version(inode) == STAT_DATA_V1) 1358 return generic_permission(inode, mask, NULL); 1359 else 1360 return generic_permission(inode, mask, reiserfs_check_acl); 1361 } 1362