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