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 <asm/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(&inode->i_mutex); 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_cache_page(mapping, n, 456 (filler_t *) mapping->a_ops->readpage, NULL); 457 if (!IS_ERR(page)) { 458 wait_on_page_locked(page); 459 kmap(page); 460 if (!PageUptodate(page)) 461 goto fail; 462 463 if (PageError(page)) 464 goto fail; 465 } 466 return page; 467 468 fail: 469 reiserfs_put_page(page); 470 return ERR_PTR(-EIO); 471 } 472 473 static inline __u32 xattr_hash(const char *msg, int len) 474 { 475 return csum_partial(msg, len, 0); 476 } 477 478 /* Generic extended attribute operations that can be used by xa plugins */ 479 480 /* 481 * inode->i_mutex: down 482 */ 483 int 484 reiserfs_xattr_set(struct inode *inode, const char *name, const void *buffer, 485 size_t buffer_size, int flags) 486 { 487 int err = 0; 488 struct file *fp; 489 struct page *page; 490 char *data; 491 struct address_space *mapping; 492 size_t file_pos = 0; 493 size_t buffer_pos = 0; 494 struct inode *xinode; 495 struct iattr newattrs; 496 __u32 xahash = 0; 497 498 if (get_inode_sd_version(inode) == STAT_DATA_V1) 499 return -EOPNOTSUPP; 500 501 /* Empty xattrs are ok, they're just empty files, no hash */ 502 if (buffer && buffer_size) 503 xahash = xattr_hash(buffer, buffer_size); 504 505 open_file: 506 fp = open_xa_file(inode, name, flags); 507 if (IS_ERR(fp)) { 508 err = PTR_ERR(fp); 509 goto out; 510 } 511 512 xinode = fp->f_dentry->d_inode; 513 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 514 515 /* we need to copy it off.. */ 516 if (xinode->i_nlink > 1) { 517 fput(fp); 518 err = reiserfs_xattr_del(inode, name); 519 if (err < 0) 520 goto out; 521 /* We just killed the old one, we're not replacing anymore */ 522 if (flags & XATTR_REPLACE) 523 flags &= ~XATTR_REPLACE; 524 goto open_file; 525 } 526 527 /* Resize it so we're ok to write there */ 528 newattrs.ia_size = buffer_size; 529 newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; 530 mutex_lock(&xinode->i_mutex); 531 err = notify_change(fp->f_dentry, &newattrs); 532 if (err) 533 goto out_filp; 534 535 mapping = xinode->i_mapping; 536 while (buffer_pos < buffer_size || buffer_pos == 0) { 537 size_t chunk; 538 size_t skip = 0; 539 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 540 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 541 chunk = PAGE_CACHE_SIZE; 542 else 543 chunk = buffer_size - buffer_pos; 544 545 page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT); 546 if (IS_ERR(page)) { 547 err = PTR_ERR(page); 548 goto out_filp; 549 } 550 551 lock_page(page); 552 data = page_address(page); 553 554 if (file_pos == 0) { 555 struct reiserfs_xattr_header *rxh; 556 skip = file_pos = sizeof(struct reiserfs_xattr_header); 557 if (chunk + skip > PAGE_CACHE_SIZE) 558 chunk = PAGE_CACHE_SIZE - skip; 559 rxh = (struct reiserfs_xattr_header *)data; 560 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 561 rxh->h_hash = cpu_to_le32(xahash); 562 } 563 564 err = mapping->a_ops->prepare_write(fp, page, page_offset, 565 page_offset + chunk + skip); 566 if (!err) { 567 if (buffer) 568 memcpy(data + skip, buffer + buffer_pos, chunk); 569 err = 570 mapping->a_ops->commit_write(fp, page, page_offset, 571 page_offset + chunk + 572 skip); 573 } 574 unlock_page(page); 575 reiserfs_put_page(page); 576 buffer_pos += chunk; 577 file_pos += chunk; 578 skip = 0; 579 if (err || buffer_size == 0 || !buffer) 580 break; 581 } 582 583 /* We can't mark the inode dirty if it's not hashed. This is the case 584 * when we're inheriting the default ACL. If we dirty it, the inode 585 * gets marked dirty, but won't (ever) make it onto the dirty list until 586 * it's synced explicitly to clear I_DIRTY. This is bad. */ 587 if (!hlist_unhashed(&inode->i_hash)) { 588 inode->i_ctime = CURRENT_TIME_SEC; 589 mark_inode_dirty(inode); 590 } 591 592 out_filp: 593 mutex_unlock(&xinode->i_mutex); 594 fput(fp); 595 596 out: 597 return err; 598 } 599 600 /* 601 * inode->i_mutex: down 602 */ 603 int 604 reiserfs_xattr_get(const struct inode *inode, const char *name, void *buffer, 605 size_t buffer_size) 606 { 607 ssize_t err = 0; 608 struct file *fp; 609 size_t isize; 610 size_t file_pos = 0; 611 size_t buffer_pos = 0; 612 struct page *page; 613 struct inode *xinode; 614 __u32 hash = 0; 615 616 if (name == NULL) 617 return -EINVAL; 618 619 /* We can't have xattrs attached to v1 items since they don't have 620 * generation numbers */ 621 if (get_inode_sd_version(inode) == STAT_DATA_V1) 622 return -EOPNOTSUPP; 623 624 fp = open_xa_file(inode, name, FL_READONLY); 625 if (IS_ERR(fp)) { 626 err = PTR_ERR(fp); 627 goto out; 628 } 629 630 xinode = fp->f_dentry->d_inode; 631 isize = xinode->i_size; 632 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 633 634 /* Just return the size needed */ 635 if (buffer == NULL) { 636 err = isize - sizeof(struct reiserfs_xattr_header); 637 goto out_dput; 638 } 639 640 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 641 err = -ERANGE; 642 goto out_dput; 643 } 644 645 while (file_pos < isize) { 646 size_t chunk; 647 char *data; 648 size_t skip = 0; 649 if (isize - file_pos > PAGE_CACHE_SIZE) 650 chunk = PAGE_CACHE_SIZE; 651 else 652 chunk = isize - file_pos; 653 654 page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT); 655 if (IS_ERR(page)) { 656 err = PTR_ERR(page); 657 goto out_dput; 658 } 659 660 lock_page(page); 661 data = page_address(page); 662 if (file_pos == 0) { 663 struct reiserfs_xattr_header *rxh = 664 (struct reiserfs_xattr_header *)data; 665 skip = file_pos = sizeof(struct reiserfs_xattr_header); 666 chunk -= skip; 667 /* Magic doesn't match up.. */ 668 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 669 unlock_page(page); 670 reiserfs_put_page(page); 671 reiserfs_warning(inode->i_sb, 672 "Invalid magic for xattr (%s) " 673 "associated with %k", name, 674 INODE_PKEY(inode)); 675 err = -EIO; 676 goto out_dput; 677 } 678 hash = le32_to_cpu(rxh->h_hash); 679 } 680 memcpy(buffer + buffer_pos, data + skip, chunk); 681 unlock_page(page); 682 reiserfs_put_page(page); 683 file_pos += chunk; 684 buffer_pos += chunk; 685 skip = 0; 686 } 687 err = isize - sizeof(struct reiserfs_xattr_header); 688 689 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 690 hash) { 691 reiserfs_warning(inode->i_sb, 692 "Invalid hash for xattr (%s) associated " 693 "with %k", name, INODE_PKEY(inode)); 694 err = -EIO; 695 } 696 697 out_dput: 698 fput(fp); 699 700 out: 701 return err; 702 } 703 704 static int 705 __reiserfs_xattr_del(struct dentry *xadir, const char *name, int namelen) 706 { 707 struct dentry *dentry; 708 struct inode *dir = xadir->d_inode; 709 int err = 0; 710 711 dentry = lookup_one_len(name, xadir, namelen); 712 if (IS_ERR(dentry)) { 713 err = PTR_ERR(dentry); 714 goto out; 715 } else if (!dentry->d_inode) { 716 err = -ENODATA; 717 goto out_file; 718 } 719 720 /* Skip directories.. */ 721 if (S_ISDIR(dentry->d_inode->i_mode)) 722 goto out_file; 723 724 if (!is_reiserfs_priv_object(dentry->d_inode)) { 725 reiserfs_warning(dir->i_sb, "OID %08x [%.*s/%.*s] doesn't have " 726 "priv flag set [parent is %sset].", 727 le32_to_cpu(INODE_PKEY(dentry->d_inode)-> 728 k_objectid), xadir->d_name.len, 729 xadir->d_name.name, namelen, name, 730 is_reiserfs_priv_object(xadir-> 731 d_inode) ? "" : 732 "not "); 733 dput(dentry); 734 return -EIO; 735 } 736 737 err = dir->i_op->unlink(dir, dentry); 738 if (!err) 739 d_delete(dentry); 740 741 out_file: 742 dput(dentry); 743 744 out: 745 return err; 746 } 747 748 int reiserfs_xattr_del(struct inode *inode, const char *name) 749 { 750 struct dentry *dir; 751 int err; 752 753 dir = open_xa_dir(inode, FL_READONLY); 754 if (IS_ERR(dir)) { 755 err = PTR_ERR(dir); 756 goto out; 757 } 758 759 err = __reiserfs_xattr_del(dir, name, strlen(name)); 760 dput(dir); 761 762 if (!err) { 763 inode->i_ctime = CURRENT_TIME_SEC; 764 mark_inode_dirty(inode); 765 } 766 767 out: 768 return err; 769 } 770 771 /* The following are side effects of other operations that aren't explicitly 772 * modifying extended attributes. This includes operations such as permissions 773 * or ownership changes, object deletions, etc. */ 774 775 static int 776 reiserfs_delete_xattrs_filler(void *buf, const char *name, int namelen, 777 loff_t offset, ino_t ino, unsigned int d_type) 778 { 779 struct dentry *xadir = (struct dentry *)buf; 780 781 return __reiserfs_xattr_del(xadir, name, namelen); 782 783 } 784 785 /* This is called w/ inode->i_mutex downed */ 786 int reiserfs_delete_xattrs(struct inode *inode) 787 { 788 struct file *fp; 789 struct dentry *dir, *root; 790 int err = 0; 791 792 /* Skip out, an xattr has no xattrs associated with it */ 793 if (is_reiserfs_priv_object(inode) || 794 get_inode_sd_version(inode) == STAT_DATA_V1 || 795 !reiserfs_xattrs(inode->i_sb)) { 796 return 0; 797 } 798 reiserfs_read_lock_xattrs(inode->i_sb); 799 dir = open_xa_dir(inode, FL_READONLY); 800 reiserfs_read_unlock_xattrs(inode->i_sb); 801 if (IS_ERR(dir)) { 802 err = PTR_ERR(dir); 803 goto out; 804 } else if (!dir->d_inode) { 805 dput(dir); 806 return 0; 807 } 808 809 fp = dentry_open(dir, NULL, O_RDWR); 810 if (IS_ERR(fp)) { 811 err = PTR_ERR(fp); 812 /* dentry_open dputs the dentry if it fails */ 813 goto out; 814 } 815 816 lock_kernel(); 817 err = xattr_readdir(fp, reiserfs_delete_xattrs_filler, dir); 818 if (err) { 819 unlock_kernel(); 820 goto out_dir; 821 } 822 823 /* Leftovers besides . and .. -- that's not good. */ 824 if (dir->d_inode->i_nlink <= 2) { 825 root = get_xa_root(inode->i_sb); 826 reiserfs_write_lock_xattrs(inode->i_sb); 827 err = vfs_rmdir(root->d_inode, dir); 828 reiserfs_write_unlock_xattrs(inode->i_sb); 829 dput(root); 830 } else { 831 reiserfs_warning(inode->i_sb, 832 "Couldn't remove all entries in directory"); 833 } 834 unlock_kernel(); 835 836 out_dir: 837 fput(fp); 838 839 out: 840 if (!err) 841 REISERFS_I(inode)->i_flags = 842 REISERFS_I(inode)->i_flags & ~i_has_xattr_dir; 843 return err; 844 } 845 846 struct reiserfs_chown_buf { 847 struct inode *inode; 848 struct dentry *xadir; 849 struct iattr *attrs; 850 }; 851 852 /* XXX: If there is a better way to do this, I'd love to hear about it */ 853 static int 854 reiserfs_chown_xattrs_filler(void *buf, const char *name, int namelen, 855 loff_t offset, ino_t ino, unsigned int d_type) 856 { 857 struct reiserfs_chown_buf *chown_buf = (struct reiserfs_chown_buf *)buf; 858 struct dentry *xafile, *xadir = chown_buf->xadir; 859 struct iattr *attrs = chown_buf->attrs; 860 int err = 0; 861 862 xafile = lookup_one_len(name, xadir, namelen); 863 if (IS_ERR(xafile)) 864 return PTR_ERR(xafile); 865 else if (!xafile->d_inode) { 866 dput(xafile); 867 return -ENODATA; 868 } 869 870 if (!S_ISDIR(xafile->d_inode->i_mode)) 871 err = notify_change(xafile, attrs); 872 dput(xafile); 873 874 return err; 875 } 876 877 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 878 { 879 struct file *fp; 880 struct dentry *dir; 881 int err = 0; 882 struct reiserfs_chown_buf buf; 883 unsigned int ia_valid = attrs->ia_valid; 884 885 /* Skip out, an xattr has no xattrs associated with it */ 886 if (is_reiserfs_priv_object(inode) || 887 get_inode_sd_version(inode) == STAT_DATA_V1 || 888 !reiserfs_xattrs(inode->i_sb)) { 889 return 0; 890 } 891 reiserfs_read_lock_xattrs(inode->i_sb); 892 dir = open_xa_dir(inode, FL_READONLY); 893 reiserfs_read_unlock_xattrs(inode->i_sb); 894 if (IS_ERR(dir)) { 895 if (PTR_ERR(dir) != -ENODATA) 896 err = PTR_ERR(dir); 897 goto out; 898 } else if (!dir->d_inode) { 899 dput(dir); 900 goto out; 901 } 902 903 fp = dentry_open(dir, NULL, O_RDWR); 904 if (IS_ERR(fp)) { 905 err = PTR_ERR(fp); 906 /* dentry_open dputs the dentry if it fails */ 907 goto out; 908 } 909 910 lock_kernel(); 911 912 attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME); 913 buf.xadir = dir; 914 buf.attrs = attrs; 915 buf.inode = inode; 916 917 err = xattr_readdir(fp, reiserfs_chown_xattrs_filler, &buf); 918 if (err) { 919 unlock_kernel(); 920 goto out_dir; 921 } 922 923 err = notify_change(dir, attrs); 924 unlock_kernel(); 925 926 out_dir: 927 fput(fp); 928 929 out: 930 attrs->ia_valid = ia_valid; 931 return err; 932 } 933 934 /* Actual operations that are exported to VFS-land */ 935 936 /* 937 * Inode operation getxattr() 938 * Preliminary locking: we down dentry->d_inode->i_mutex 939 */ 940 ssize_t 941 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 942 size_t size) 943 { 944 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 945 int err; 946 947 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 948 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 949 return -EOPNOTSUPP; 950 951 reiserfs_read_lock_xattr_i(dentry->d_inode); 952 reiserfs_read_lock_xattrs(dentry->d_sb); 953 err = xah->get(dentry->d_inode, name, buffer, size); 954 reiserfs_read_unlock_xattrs(dentry->d_sb); 955 reiserfs_read_unlock_xattr_i(dentry->d_inode); 956 return err; 957 } 958 959 /* 960 * Inode operation setxattr() 961 * 962 * dentry->d_inode->i_mutex down 963 */ 964 int 965 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 966 size_t size, int flags) 967 { 968 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 969 int err; 970 int lock; 971 972 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 973 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 974 return -EOPNOTSUPP; 975 976 reiserfs_write_lock_xattr_i(dentry->d_inode); 977 lock = !has_xattr_dir(dentry->d_inode); 978 if (lock) 979 reiserfs_write_lock_xattrs(dentry->d_sb); 980 else 981 reiserfs_read_lock_xattrs(dentry->d_sb); 982 err = xah->set(dentry->d_inode, name, value, size, flags); 983 if (lock) 984 reiserfs_write_unlock_xattrs(dentry->d_sb); 985 else 986 reiserfs_read_unlock_xattrs(dentry->d_sb); 987 reiserfs_write_unlock_xattr_i(dentry->d_inode); 988 return err; 989 } 990 991 /* 992 * Inode operation removexattr() 993 * 994 * dentry->d_inode->i_mutex down 995 */ 996 int reiserfs_removexattr(struct dentry *dentry, const char *name) 997 { 998 int err; 999 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 1000 1001 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 1002 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 1003 return -EOPNOTSUPP; 1004 1005 reiserfs_write_lock_xattr_i(dentry->d_inode); 1006 reiserfs_read_lock_xattrs(dentry->d_sb); 1007 1008 /* Deletion pre-operation */ 1009 if (xah->del) { 1010 err = xah->del(dentry->d_inode, name); 1011 if (err) 1012 goto out; 1013 } 1014 1015 err = reiserfs_xattr_del(dentry->d_inode, name); 1016 1017 dentry->d_inode->i_ctime = CURRENT_TIME_SEC; 1018 mark_inode_dirty(dentry->d_inode); 1019 1020 out: 1021 reiserfs_read_unlock_xattrs(dentry->d_sb); 1022 reiserfs_write_unlock_xattr_i(dentry->d_inode); 1023 return err; 1024 } 1025 1026 /* This is what filldir will use: 1027 * r_pos will always contain the amount of space required for the entire 1028 * list. If r_pos becomes larger than r_size, we need more space and we 1029 * return an error indicating this. If r_pos is less than r_size, then we've 1030 * filled the buffer successfully and we return success */ 1031 struct reiserfs_listxattr_buf { 1032 int r_pos; 1033 int r_size; 1034 char *r_buf; 1035 struct inode *r_inode; 1036 }; 1037 1038 static int 1039 reiserfs_listxattr_filler(void *buf, const char *name, int namelen, 1040 loff_t offset, ino_t ino, unsigned int d_type) 1041 { 1042 struct reiserfs_listxattr_buf *b = (struct reiserfs_listxattr_buf *)buf; 1043 int len = 0; 1044 if (name[0] != '.' 1045 || (namelen != 1 && (name[1] != '.' || namelen != 2))) { 1046 struct reiserfs_xattr_handler *xah = 1047 find_xattr_handler_prefix(name); 1048 if (!xah) 1049 return 0; /* Unsupported xattr name, skip it */ 1050 1051 /* We call ->list() twice because the operation isn't required to just 1052 * return the name back - we want to make sure we have enough space */ 1053 len += xah->list(b->r_inode, name, namelen, NULL); 1054 1055 if (len) { 1056 if (b->r_pos + len + 1 <= b->r_size) { 1057 char *p = b->r_buf + b->r_pos; 1058 p += xah->list(b->r_inode, name, namelen, p); 1059 *p++ = '\0'; 1060 } 1061 b->r_pos += len + 1; 1062 } 1063 } 1064 1065 return 0; 1066 } 1067 1068 /* 1069 * Inode operation listxattr() 1070 * 1071 * Preliminary locking: we down dentry->d_inode->i_mutex 1072 */ 1073 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 1074 { 1075 struct file *fp; 1076 struct dentry *dir; 1077 int err = 0; 1078 struct reiserfs_listxattr_buf buf; 1079 1080 if (!dentry->d_inode) 1081 return -EINVAL; 1082 1083 if (!reiserfs_xattrs(dentry->d_sb) || 1084 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 1085 return -EOPNOTSUPP; 1086 1087 reiserfs_read_lock_xattr_i(dentry->d_inode); 1088 reiserfs_read_lock_xattrs(dentry->d_sb); 1089 dir = open_xa_dir(dentry->d_inode, FL_READONLY); 1090 reiserfs_read_unlock_xattrs(dentry->d_sb); 1091 if (IS_ERR(dir)) { 1092 err = PTR_ERR(dir); 1093 if (err == -ENODATA) 1094 err = 0; /* Not an error if there aren't any xattrs */ 1095 goto out; 1096 } 1097 1098 fp = dentry_open(dir, NULL, O_RDWR); 1099 if (IS_ERR(fp)) { 1100 err = PTR_ERR(fp); 1101 /* dentry_open dputs the dentry if it fails */ 1102 goto out; 1103 } 1104 1105 buf.r_buf = buffer; 1106 buf.r_size = buffer ? size : 0; 1107 buf.r_pos = 0; 1108 buf.r_inode = dentry->d_inode; 1109 1110 REISERFS_I(dentry->d_inode)->i_flags |= i_has_xattr_dir; 1111 1112 err = xattr_readdir(fp, reiserfs_listxattr_filler, &buf); 1113 if (err) 1114 goto out_dir; 1115 1116 if (buf.r_pos > buf.r_size && buffer != NULL) 1117 err = -ERANGE; 1118 else 1119 err = buf.r_pos; 1120 1121 out_dir: 1122 fput(fp); 1123 1124 out: 1125 reiserfs_read_unlock_xattr_i(dentry->d_inode); 1126 return err; 1127 } 1128 1129 /* This is the implementation for the xattr plugin infrastructure */ 1130 static struct list_head xattr_handlers = LIST_HEAD_INIT(xattr_handlers); 1131 static DEFINE_RWLOCK(handler_lock); 1132 1133 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char 1134 *prefix) 1135 { 1136 struct reiserfs_xattr_handler *xah = NULL; 1137 struct list_head *p; 1138 1139 read_lock(&handler_lock); 1140 list_for_each(p, &xattr_handlers) { 1141 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1142 if (strncmp(xah->prefix, prefix, strlen(xah->prefix)) == 0) 1143 break; 1144 xah = NULL; 1145 } 1146 1147 read_unlock(&handler_lock); 1148 return xah; 1149 } 1150 1151 static void __unregister_handlers(void) 1152 { 1153 struct reiserfs_xattr_handler *xah; 1154 struct list_head *p, *tmp; 1155 1156 list_for_each_safe(p, tmp, &xattr_handlers) { 1157 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1158 if (xah->exit) 1159 xah->exit(); 1160 1161 list_del_init(p); 1162 } 1163 INIT_LIST_HEAD(&xattr_handlers); 1164 } 1165 1166 int __init reiserfs_xattr_register_handlers(void) 1167 { 1168 int err = 0; 1169 struct reiserfs_xattr_handler *xah; 1170 struct list_head *p; 1171 1172 write_lock(&handler_lock); 1173 1174 /* If we're already initialized, nothing to do */ 1175 if (!list_empty(&xattr_handlers)) { 1176 write_unlock(&handler_lock); 1177 return 0; 1178 } 1179 1180 /* Add the handlers */ 1181 list_add_tail(&user_handler.handlers, &xattr_handlers); 1182 list_add_tail(&trusted_handler.handlers, &xattr_handlers); 1183 #ifdef CONFIG_REISERFS_FS_SECURITY 1184 list_add_tail(&security_handler.handlers, &xattr_handlers); 1185 #endif 1186 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 1187 list_add_tail(&posix_acl_access_handler.handlers, &xattr_handlers); 1188 list_add_tail(&posix_acl_default_handler.handlers, &xattr_handlers); 1189 #endif 1190 1191 /* Run initializers, if available */ 1192 list_for_each(p, &xattr_handlers) { 1193 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1194 if (xah->init) { 1195 err = xah->init(); 1196 if (err) { 1197 list_del_init(p); 1198 break; 1199 } 1200 } 1201 } 1202 1203 /* Clean up other handlers, if any failed */ 1204 if (err) 1205 __unregister_handlers(); 1206 1207 write_unlock(&handler_lock); 1208 return err; 1209 } 1210 1211 void reiserfs_xattr_unregister_handlers(void) 1212 { 1213 write_lock(&handler_lock); 1214 __unregister_handlers(); 1215 write_unlock(&handler_lock); 1216 } 1217 1218 /* This will catch lookups from the fs root to .reiserfs_priv */ 1219 static int 1220 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 1221 { 1222 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 1223 if (name->len == priv_root->d_name.len && 1224 name->hash == priv_root->d_name.hash && 1225 !memcmp(name->name, priv_root->d_name.name, name->len)) { 1226 return -ENOENT; 1227 } else if (q1->len == name->len && 1228 !memcmp(q1->name, name->name, name->len)) 1229 return 0; 1230 return 1; 1231 } 1232 1233 static struct dentry_operations xattr_lookup_poison_ops = { 1234 .d_compare = xattr_lookup_poison, 1235 }; 1236 1237 /* We need to take a copy of the mount flags since things like 1238 * MS_RDONLY don't get set until *after* we're called. 1239 * mount_flags != mount_options */ 1240 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1241 { 1242 int err = 0; 1243 1244 /* We need generation numbers to ensure that the oid mapping is correct 1245 * v3.5 filesystems don't have them. */ 1246 if (!old_format_only(s)) { 1247 set_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1248 } else if (reiserfs_xattrs_optional(s)) { 1249 /* Old format filesystem, but optional xattrs have been enabled 1250 * at mount time. Error out. */ 1251 reiserfs_warning(s, "xattrs/ACLs not supported on pre v3.6 " 1252 "format filesystem. Failing mount."); 1253 err = -EOPNOTSUPP; 1254 goto error; 1255 } else { 1256 /* Old format filesystem, but no optional xattrs have been enabled. This 1257 * means we silently disable xattrs on the filesystem. */ 1258 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1259 } 1260 1261 /* If we don't have the privroot located yet - go find it */ 1262 if (reiserfs_xattrs(s) && !REISERFS_SB(s)->priv_root) { 1263 struct dentry *dentry; 1264 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 1265 strlen(PRIVROOT_NAME)); 1266 if (!IS_ERR(dentry)) { 1267 if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) { 1268 struct inode *inode = dentry->d_parent->d_inode; 1269 mutex_lock(&inode->i_mutex); 1270 err = inode->i_op->mkdir(inode, dentry, 0700); 1271 mutex_unlock(&inode->i_mutex); 1272 if (err) { 1273 dput(dentry); 1274 dentry = NULL; 1275 } 1276 1277 if (dentry && dentry->d_inode) 1278 reiserfs_warning(s, 1279 "Created %s on %s - reserved for " 1280 "xattr storage.", 1281 PRIVROOT_NAME, 1282 reiserfs_bdevname 1283 (inode->i_sb)); 1284 } else if (!dentry->d_inode) { 1285 dput(dentry); 1286 dentry = NULL; 1287 } 1288 } else 1289 err = PTR_ERR(dentry); 1290 1291 if (!err && dentry) { 1292 s->s_root->d_op = &xattr_lookup_poison_ops; 1293 reiserfs_mark_inode_private(dentry->d_inode); 1294 REISERFS_SB(s)->priv_root = dentry; 1295 } else if (!(mount_flags & MS_RDONLY)) { /* xattrs are unavailable */ 1296 /* If we're read-only it just means that the dir hasn't been 1297 * created. Not an error -- just no xattrs on the fs. We'll 1298 * check again if we go read-write */ 1299 reiserfs_warning(s, "xattrs/ACLs enabled and couldn't " 1300 "find/create .reiserfs_priv. Failing mount."); 1301 err = -EOPNOTSUPP; 1302 } 1303 } 1304 1305 error: 1306 /* This is only nonzero if there was an error initializing the xattr 1307 * directory or if there is a condition where we don't support them. */ 1308 if (err) { 1309 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1310 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1311 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1312 } 1313 1314 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1315 s->s_flags = s->s_flags & ~MS_POSIXACL; 1316 if (reiserfs_posixacl(s)) 1317 s->s_flags |= MS_POSIXACL; 1318 1319 return err; 1320 } 1321 1322 int reiserfs_permission(struct inode *inode, int mask, struct nameidata *nd) 1323 { 1324 umode_t mode = inode->i_mode; 1325 1326 if (mask & MAY_WRITE) { 1327 /* 1328 * Nobody gets write access to a read-only fs. 1329 */ 1330 if (IS_RDONLY(inode) && 1331 (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) 1332 return -EROFS; 1333 1334 /* 1335 * Nobody gets write access to an immutable file. 1336 */ 1337 if (IS_IMMUTABLE(inode)) 1338 return -EACCES; 1339 } 1340 1341 /* We don't do permission checks on the internal objects. 1342 * Permissions are determined by the "owning" object. */ 1343 if (is_reiserfs_priv_object(inode)) 1344 return 0; 1345 1346 if (current->fsuid == inode->i_uid) { 1347 mode >>= 6; 1348 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 1349 } else if (reiserfs_posixacl(inode->i_sb) && 1350 get_inode_sd_version(inode) != STAT_DATA_V1) { 1351 struct posix_acl *acl; 1352 1353 /* ACL can't contain additional permissions if 1354 the ACL_MASK entry is 0 */ 1355 if (!(mode & S_IRWXG)) 1356 goto check_groups; 1357 1358 reiserfs_read_lock_xattr_i(inode); 1359 reiserfs_read_lock_xattrs(inode->i_sb); 1360 1361 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 1362 1363 reiserfs_read_unlock_xattrs(inode->i_sb); 1364 reiserfs_read_unlock_xattr_i(inode); 1365 1366 if (IS_ERR(acl)) { 1367 if (PTR_ERR(acl) == -ENODATA) 1368 goto check_groups; 1369 return PTR_ERR(acl); 1370 } 1371 1372 if (acl) { 1373 int err = posix_acl_permission(inode, acl, mask); 1374 posix_acl_release(acl); 1375 if (err == -EACCES) { 1376 goto check_capabilities; 1377 } 1378 return err; 1379 } else { 1380 goto check_groups; 1381 } 1382 #endif 1383 } else { 1384 check_groups: 1385 if (in_group_p(inode->i_gid)) 1386 mode >>= 3; 1387 } 1388 1389 /* 1390 * If the DACs are ok we don't need any capability check. 1391 */ 1392 if (((mode & mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) == mask)) 1393 return 0; 1394 1395 check_capabilities: 1396 /* 1397 * Read/write DACs are always overridable. 1398 * Executable DACs are overridable if at least one exec bit is set. 1399 */ 1400 if (!(mask & MAY_EXEC) || 1401 (inode->i_mode & S_IXUGO) || S_ISDIR(inode->i_mode)) 1402 if (capable(CAP_DAC_OVERRIDE)) 1403 return 0; 1404 1405 /* 1406 * Searching includes executable on directories, else just read. 1407 */ 1408 if (mask == MAY_READ || (S_ISDIR(inode->i_mode) && !(mask & MAY_WRITE))) 1409 if (capable(CAP_DAC_READ_SEARCH)) 1410 return 0; 1411 1412 return -EACCES; 1413 } 1414