1 /* 2 * linux/fs/reiserfs/xattr.c 3 * 4 * Copyright (c) 2002 by Jeff Mahoney, <jeffm@suse.com> 5 * 6 */ 7 8 /* 9 * In order to implement EA/ACLs in a clean, backwards compatible manner, 10 * they are implemented as files in a "private" directory. 11 * Each EA is in it's own file, with the directory layout like so (/ is assumed 12 * to be relative to fs root). Inside the /.reiserfs_priv/xattrs directory, 13 * directories named using the capital-hex form of the objectid and 14 * generation number are used. Inside each directory are individual files 15 * named with the name of the extended attribute. 16 * 17 * So, for objectid 12648430, we could have: 18 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_access 19 * /.reiserfs_priv/xattrs/C0FFEE.0/system.posix_acl_default 20 * /.reiserfs_priv/xattrs/C0FFEE.0/user.Content-Type 21 * .. or similar. 22 * 23 * The file contents are the text of the EA. The size is known based on the 24 * stat data describing the file. 25 * 26 * In the case of system.posix_acl_access and system.posix_acl_default, since 27 * these are special cases for filesystem ACLs, they are interpreted by the 28 * kernel, in addition, they are negatively and positively cached and attached 29 * to the inode so that unnecessary lookups are avoided. 30 */ 31 32 #include <linux/reiserfs_fs.h> 33 #include <linux/capability.h> 34 #include <linux/dcache.h> 35 #include <linux/namei.h> 36 #include <linux/errno.h> 37 #include <linux/fs.h> 38 #include <linux/file.h> 39 #include <linux/pagemap.h> 40 #include <linux/xattr.h> 41 #include <linux/reiserfs_xattr.h> 42 #include <linux/reiserfs_acl.h> 43 #include <asm/uaccess.h> 44 #include <net/checksum.h> 45 #include <linux/smp_lock.h> 46 #include <linux/stat.h> 47 #include <asm/semaphore.h> 48 49 #define FL_READONLY 128 50 #define FL_DIR_SEM_HELD 256 51 #define PRIVROOT_NAME ".reiserfs_priv" 52 #define XAROOT_NAME "xattrs" 53 54 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char 55 *prefix); 56 57 /* Returns the dentry referring to the root of the extended attribute 58 * directory tree. If it has already been retrieved, it is used. If it 59 * hasn't been created and the flags indicate creation is allowed, we 60 * attempt to create it. On error, we return a pointer-encoded error. 61 */ 62 static struct dentry *get_xa_root(struct super_block *sb, int flags) 63 { 64 struct dentry *privroot = dget(REISERFS_SB(sb)->priv_root); 65 struct dentry *xaroot; 66 67 /* This needs to be created at mount-time */ 68 if (!privroot) 69 return ERR_PTR(-ENODATA); 70 71 mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR); 72 if (REISERFS_SB(sb)->xattr_root) { 73 xaroot = dget(REISERFS_SB(sb)->xattr_root); 74 goto out; 75 } 76 77 xaroot = lookup_one_len(XAROOT_NAME, privroot, strlen(XAROOT_NAME)); 78 if (IS_ERR(xaroot)) { 79 goto out; 80 } else if (!xaroot->d_inode) { 81 int err = -ENODATA; 82 if (flags == 0 || flags & XATTR_CREATE) 83 err = privroot->d_inode->i_op->mkdir(privroot->d_inode, 84 xaroot, 0700); 85 if (err) { 86 dput(xaroot); 87 xaroot = ERR_PTR(err); 88 goto out; 89 } 90 } 91 REISERFS_SB(sb)->xattr_root = dget(xaroot); 92 93 out: 94 mutex_unlock(&privroot->d_inode->i_mutex); 95 dput(privroot); 96 return xaroot; 97 } 98 99 /* Opens the directory corresponding to the inode's extended attribute store. 100 * If flags allow, the tree to the directory may be created. If creation is 101 * prohibited, -ENODATA is returned. */ 102 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 103 { 104 struct dentry *xaroot, *xadir; 105 char namebuf[17]; 106 107 xaroot = get_xa_root(inode->i_sb, flags); 108 if (IS_ERR(xaroot)) 109 return xaroot; 110 111 /* ok, we have xaroot open */ 112 snprintf(namebuf, sizeof(namebuf), "%X.%X", 113 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 114 inode->i_generation); 115 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); 116 if (IS_ERR(xadir)) { 117 dput(xaroot); 118 return xadir; 119 } 120 121 if (!xadir->d_inode) { 122 int err; 123 if (flags == 0 || flags & XATTR_CREATE) { 124 /* Although there is nothing else trying to create this directory, 125 * another directory with the same hash may be created, so we need 126 * to protect against that */ 127 err = 128 xaroot->d_inode->i_op->mkdir(xaroot->d_inode, xadir, 129 0700); 130 if (err) { 131 dput(xaroot); 132 dput(xadir); 133 return ERR_PTR(err); 134 } 135 } 136 if (!xadir->d_inode) { 137 dput(xaroot); 138 dput(xadir); 139 return ERR_PTR(-ENODATA); 140 } 141 } 142 143 dput(xaroot); 144 return xadir; 145 } 146 147 /* Returns a dentry corresponding to a specific extended attribute file 148 * for the inode. If flags allow, the file is created. Otherwise, a 149 * valid or negative dentry, or an error is returned. */ 150 static struct dentry *get_xa_file_dentry(const struct inode *inode, 151 const char *name, int flags) 152 { 153 struct dentry *xadir, *xafile; 154 int err = 0; 155 156 xadir = open_xa_dir(inode, flags); 157 if (IS_ERR(xadir)) { 158 return ERR_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 kmap(page); 414 if (PageError(page)) 415 goto fail; 416 } 417 return page; 418 419 fail: 420 reiserfs_put_page(page); 421 return ERR_PTR(-EIO); 422 } 423 424 static inline __u32 xattr_hash(const char *msg, int len) 425 { 426 return csum_partial(msg, len, 0); 427 } 428 429 /* Generic extended attribute operations that can be used by xa plugins */ 430 431 /* 432 * inode->i_mutex: down 433 */ 434 int 435 reiserfs_xattr_set(struct inode *inode, const char *name, const void *buffer, 436 size_t buffer_size, int flags) 437 { 438 int err = 0; 439 struct file *fp; 440 struct page *page; 441 char *data; 442 struct address_space *mapping; 443 size_t file_pos = 0; 444 size_t buffer_pos = 0; 445 struct inode *xinode; 446 struct iattr newattrs; 447 __u32 xahash = 0; 448 449 if (get_inode_sd_version(inode) == STAT_DATA_V1) 450 return -EOPNOTSUPP; 451 452 /* Empty xattrs are ok, they're just empty files, no hash */ 453 if (buffer && buffer_size) 454 xahash = xattr_hash(buffer, buffer_size); 455 456 open_file: 457 fp = open_xa_file(inode, name, flags); 458 if (IS_ERR(fp)) { 459 err = PTR_ERR(fp); 460 goto out; 461 } 462 463 xinode = fp->f_path.dentry->d_inode; 464 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 465 466 /* we need to copy it off.. */ 467 if (xinode->i_nlink > 1) { 468 fput(fp); 469 err = reiserfs_xattr_del(inode, name); 470 if (err < 0) 471 goto out; 472 /* We just killed the old one, we're not replacing anymore */ 473 if (flags & XATTR_REPLACE) 474 flags &= ~XATTR_REPLACE; 475 goto open_file; 476 } 477 478 /* Resize it so we're ok to write there */ 479 newattrs.ia_size = buffer_size; 480 newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; 481 mutex_lock(&xinode->i_mutex); 482 err = notify_change(fp->f_path.dentry, &newattrs); 483 if (err) 484 goto out_filp; 485 486 mapping = xinode->i_mapping; 487 while (buffer_pos < buffer_size || buffer_pos == 0) { 488 size_t chunk; 489 size_t skip = 0; 490 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 491 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 492 chunk = PAGE_CACHE_SIZE; 493 else 494 chunk = buffer_size - buffer_pos; 495 496 page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT); 497 if (IS_ERR(page)) { 498 err = PTR_ERR(page); 499 goto out_filp; 500 } 501 502 lock_page(page); 503 data = page_address(page); 504 505 if (file_pos == 0) { 506 struct reiserfs_xattr_header *rxh; 507 skip = file_pos = sizeof(struct reiserfs_xattr_header); 508 if (chunk + skip > PAGE_CACHE_SIZE) 509 chunk = PAGE_CACHE_SIZE - skip; 510 rxh = (struct reiserfs_xattr_header *)data; 511 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 512 rxh->h_hash = cpu_to_le32(xahash); 513 } 514 515 err = mapping->a_ops->prepare_write(fp, page, page_offset, 516 page_offset + chunk + skip); 517 if (!err) { 518 if (buffer) 519 memcpy(data + skip, buffer + buffer_pos, chunk); 520 err = 521 mapping->a_ops->commit_write(fp, page, page_offset, 522 page_offset + chunk + 523 skip); 524 } 525 unlock_page(page); 526 reiserfs_put_page(page); 527 buffer_pos += chunk; 528 file_pos += chunk; 529 skip = 0; 530 if (err || buffer_size == 0 || !buffer) 531 break; 532 } 533 534 /* We can't mark the inode dirty if it's not hashed. This is the case 535 * when we're inheriting the default ACL. If we dirty it, the inode 536 * gets marked dirty, but won't (ever) make it onto the dirty list until 537 * it's synced explicitly to clear I_DIRTY. This is bad. */ 538 if (!hlist_unhashed(&inode->i_hash)) { 539 inode->i_ctime = CURRENT_TIME_SEC; 540 mark_inode_dirty(inode); 541 } 542 543 out_filp: 544 mutex_unlock(&xinode->i_mutex); 545 fput(fp); 546 547 out: 548 return err; 549 } 550 551 /* 552 * inode->i_mutex: down 553 */ 554 int 555 reiserfs_xattr_get(const struct inode *inode, const char *name, void *buffer, 556 size_t buffer_size) 557 { 558 ssize_t err = 0; 559 struct file *fp; 560 size_t isize; 561 size_t file_pos = 0; 562 size_t buffer_pos = 0; 563 struct page *page; 564 struct inode *xinode; 565 __u32 hash = 0; 566 567 if (name == NULL) 568 return -EINVAL; 569 570 /* We can't have xattrs attached to v1 items since they don't have 571 * generation numbers */ 572 if (get_inode_sd_version(inode) == STAT_DATA_V1) 573 return -EOPNOTSUPP; 574 575 fp = open_xa_file(inode, name, FL_READONLY); 576 if (IS_ERR(fp)) { 577 err = PTR_ERR(fp); 578 goto out; 579 } 580 581 xinode = fp->f_path.dentry->d_inode; 582 isize = xinode->i_size; 583 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 584 585 /* Just return the size needed */ 586 if (buffer == NULL) { 587 err = isize - sizeof(struct reiserfs_xattr_header); 588 goto out_dput; 589 } 590 591 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 592 err = -ERANGE; 593 goto out_dput; 594 } 595 596 while (file_pos < isize) { 597 size_t chunk; 598 char *data; 599 size_t skip = 0; 600 if (isize - file_pos > PAGE_CACHE_SIZE) 601 chunk = PAGE_CACHE_SIZE; 602 else 603 chunk = isize - file_pos; 604 605 page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT); 606 if (IS_ERR(page)) { 607 err = PTR_ERR(page); 608 goto out_dput; 609 } 610 611 lock_page(page); 612 data = page_address(page); 613 if (file_pos == 0) { 614 struct reiserfs_xattr_header *rxh = 615 (struct reiserfs_xattr_header *)data; 616 skip = file_pos = sizeof(struct reiserfs_xattr_header); 617 chunk -= skip; 618 /* Magic doesn't match up.. */ 619 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 620 unlock_page(page); 621 reiserfs_put_page(page); 622 reiserfs_warning(inode->i_sb, 623 "Invalid magic for xattr (%s) " 624 "associated with %k", name, 625 INODE_PKEY(inode)); 626 err = -EIO; 627 goto out_dput; 628 } 629 hash = le32_to_cpu(rxh->h_hash); 630 } 631 memcpy(buffer + buffer_pos, data + skip, chunk); 632 unlock_page(page); 633 reiserfs_put_page(page); 634 file_pos += chunk; 635 buffer_pos += chunk; 636 skip = 0; 637 } 638 err = isize - sizeof(struct reiserfs_xattr_header); 639 640 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 641 hash) { 642 reiserfs_warning(inode->i_sb, 643 "Invalid hash for xattr (%s) associated " 644 "with %k", name, INODE_PKEY(inode)); 645 err = -EIO; 646 } 647 648 out_dput: 649 fput(fp); 650 651 out: 652 return err; 653 } 654 655 static int 656 __reiserfs_xattr_del(struct dentry *xadir, const char *name, int namelen) 657 { 658 struct dentry *dentry; 659 struct inode *dir = xadir->d_inode; 660 int err = 0; 661 662 dentry = lookup_one_len(name, xadir, namelen); 663 if (IS_ERR(dentry)) { 664 err = PTR_ERR(dentry); 665 goto out; 666 } else if (!dentry->d_inode) { 667 err = -ENODATA; 668 goto out_file; 669 } 670 671 /* Skip directories.. */ 672 if (S_ISDIR(dentry->d_inode->i_mode)) 673 goto out_file; 674 675 if (!is_reiserfs_priv_object(dentry->d_inode)) { 676 reiserfs_warning(dir->i_sb, "OID %08x [%.*s/%.*s] doesn't have " 677 "priv flag set [parent is %sset].", 678 le32_to_cpu(INODE_PKEY(dentry->d_inode)-> 679 k_objectid), xadir->d_name.len, 680 xadir->d_name.name, namelen, name, 681 is_reiserfs_priv_object(xadir-> 682 d_inode) ? "" : 683 "not "); 684 dput(dentry); 685 return -EIO; 686 } 687 688 err = dir->i_op->unlink(dir, dentry); 689 if (!err) 690 d_delete(dentry); 691 692 out_file: 693 dput(dentry); 694 695 out: 696 return err; 697 } 698 699 int reiserfs_xattr_del(struct inode *inode, const char *name) 700 { 701 struct dentry *dir; 702 int err; 703 704 dir = open_xa_dir(inode, FL_READONLY); 705 if (IS_ERR(dir)) { 706 err = PTR_ERR(dir); 707 goto out; 708 } 709 710 err = __reiserfs_xattr_del(dir, name, strlen(name)); 711 dput(dir); 712 713 if (!err) { 714 inode->i_ctime = CURRENT_TIME_SEC; 715 mark_inode_dirty(inode); 716 } 717 718 out: 719 return err; 720 } 721 722 /* The following are side effects of other operations that aren't explicitly 723 * modifying extended attributes. This includes operations such as permissions 724 * or ownership changes, object deletions, etc. */ 725 726 static int 727 reiserfs_delete_xattrs_filler(void *buf, const char *name, int namelen, 728 loff_t offset, u64 ino, unsigned int d_type) 729 { 730 struct dentry *xadir = (struct dentry *)buf; 731 732 return __reiserfs_xattr_del(xadir, name, namelen); 733 734 } 735 736 /* This is called w/ inode->i_mutex downed */ 737 int reiserfs_delete_xattrs(struct inode *inode) 738 { 739 struct file *fp; 740 struct dentry *dir, *root; 741 int err = 0; 742 743 /* Skip out, an xattr has no xattrs associated with it */ 744 if (is_reiserfs_priv_object(inode) || 745 get_inode_sd_version(inode) == STAT_DATA_V1 || 746 !reiserfs_xattrs(inode->i_sb)) { 747 return 0; 748 } 749 reiserfs_read_lock_xattrs(inode->i_sb); 750 dir = open_xa_dir(inode, FL_READONLY); 751 reiserfs_read_unlock_xattrs(inode->i_sb); 752 if (IS_ERR(dir)) { 753 err = PTR_ERR(dir); 754 goto out; 755 } else if (!dir->d_inode) { 756 dput(dir); 757 return 0; 758 } 759 760 fp = dentry_open(dir, NULL, O_RDWR); 761 if (IS_ERR(fp)) { 762 err = PTR_ERR(fp); 763 /* dentry_open dputs the dentry if it fails */ 764 goto out; 765 } 766 767 lock_kernel(); 768 err = xattr_readdir(fp, reiserfs_delete_xattrs_filler, dir); 769 if (err) { 770 unlock_kernel(); 771 goto out_dir; 772 } 773 774 /* Leftovers besides . and .. -- that's not good. */ 775 if (dir->d_inode->i_nlink <= 2) { 776 root = get_xa_root(inode->i_sb, XATTR_REPLACE); 777 reiserfs_write_lock_xattrs(inode->i_sb); 778 err = vfs_rmdir(root->d_inode, dir); 779 reiserfs_write_unlock_xattrs(inode->i_sb); 780 dput(root); 781 } else { 782 reiserfs_warning(inode->i_sb, 783 "Couldn't remove all entries in directory"); 784 } 785 unlock_kernel(); 786 787 out_dir: 788 fput(fp); 789 790 out: 791 if (!err) 792 REISERFS_I(inode)->i_flags = 793 REISERFS_I(inode)->i_flags & ~i_has_xattr_dir; 794 return err; 795 } 796 797 struct reiserfs_chown_buf { 798 struct inode *inode; 799 struct dentry *xadir; 800 struct iattr *attrs; 801 }; 802 803 /* XXX: If there is a better way to do this, I'd love to hear about it */ 804 static int 805 reiserfs_chown_xattrs_filler(void *buf, const char *name, int namelen, 806 loff_t offset, u64 ino, unsigned int d_type) 807 { 808 struct reiserfs_chown_buf *chown_buf = (struct reiserfs_chown_buf *)buf; 809 struct dentry *xafile, *xadir = chown_buf->xadir; 810 struct iattr *attrs = chown_buf->attrs; 811 int err = 0; 812 813 xafile = lookup_one_len(name, xadir, namelen); 814 if (IS_ERR(xafile)) 815 return PTR_ERR(xafile); 816 else if (!xafile->d_inode) { 817 dput(xafile); 818 return -ENODATA; 819 } 820 821 if (!S_ISDIR(xafile->d_inode->i_mode)) 822 err = notify_change(xafile, attrs); 823 dput(xafile); 824 825 return err; 826 } 827 828 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 829 { 830 struct file *fp; 831 struct dentry *dir; 832 int err = 0; 833 struct reiserfs_chown_buf buf; 834 unsigned int ia_valid = attrs->ia_valid; 835 836 /* Skip out, an xattr has no xattrs associated with it */ 837 if (is_reiserfs_priv_object(inode) || 838 get_inode_sd_version(inode) == STAT_DATA_V1 || 839 !reiserfs_xattrs(inode->i_sb)) { 840 return 0; 841 } 842 reiserfs_read_lock_xattrs(inode->i_sb); 843 dir = open_xa_dir(inode, FL_READONLY); 844 reiserfs_read_unlock_xattrs(inode->i_sb); 845 if (IS_ERR(dir)) { 846 if (PTR_ERR(dir) != -ENODATA) 847 err = PTR_ERR(dir); 848 goto out; 849 } else if (!dir->d_inode) { 850 dput(dir); 851 goto out; 852 } 853 854 fp = dentry_open(dir, NULL, O_RDWR); 855 if (IS_ERR(fp)) { 856 err = PTR_ERR(fp); 857 /* dentry_open dputs the dentry if it fails */ 858 goto out; 859 } 860 861 lock_kernel(); 862 863 attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME); 864 buf.xadir = dir; 865 buf.attrs = attrs; 866 buf.inode = inode; 867 868 err = xattr_readdir(fp, reiserfs_chown_xattrs_filler, &buf); 869 if (err) { 870 unlock_kernel(); 871 goto out_dir; 872 } 873 874 err = notify_change(dir, attrs); 875 unlock_kernel(); 876 877 out_dir: 878 fput(fp); 879 880 out: 881 attrs->ia_valid = ia_valid; 882 return err; 883 } 884 885 /* Actual operations that are exported to VFS-land */ 886 887 /* 888 * Inode operation getxattr() 889 * Preliminary locking: we down dentry->d_inode->i_mutex 890 */ 891 ssize_t 892 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 893 size_t size) 894 { 895 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 896 int err; 897 898 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 899 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 900 return -EOPNOTSUPP; 901 902 reiserfs_read_lock_xattr_i(dentry->d_inode); 903 reiserfs_read_lock_xattrs(dentry->d_sb); 904 err = xah->get(dentry->d_inode, name, buffer, size); 905 reiserfs_read_unlock_xattrs(dentry->d_sb); 906 reiserfs_read_unlock_xattr_i(dentry->d_inode); 907 return err; 908 } 909 910 /* 911 * Inode operation setxattr() 912 * 913 * dentry->d_inode->i_mutex down 914 */ 915 int 916 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 917 size_t size, int flags) 918 { 919 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 920 int err; 921 int lock; 922 923 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 924 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 925 return -EOPNOTSUPP; 926 927 reiserfs_write_lock_xattr_i(dentry->d_inode); 928 lock = !has_xattr_dir(dentry->d_inode); 929 if (lock) 930 reiserfs_write_lock_xattrs(dentry->d_sb); 931 else 932 reiserfs_read_lock_xattrs(dentry->d_sb); 933 err = xah->set(dentry->d_inode, name, value, size, flags); 934 if (lock) 935 reiserfs_write_unlock_xattrs(dentry->d_sb); 936 else 937 reiserfs_read_unlock_xattrs(dentry->d_sb); 938 reiserfs_write_unlock_xattr_i(dentry->d_inode); 939 return err; 940 } 941 942 /* 943 * Inode operation removexattr() 944 * 945 * dentry->d_inode->i_mutex down 946 */ 947 int reiserfs_removexattr(struct dentry *dentry, const char *name) 948 { 949 int err; 950 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 951 952 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 953 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 954 return -EOPNOTSUPP; 955 956 reiserfs_write_lock_xattr_i(dentry->d_inode); 957 reiserfs_read_lock_xattrs(dentry->d_sb); 958 959 /* Deletion pre-operation */ 960 if (xah->del) { 961 err = xah->del(dentry->d_inode, name); 962 if (err) 963 goto out; 964 } 965 966 err = reiserfs_xattr_del(dentry->d_inode, name); 967 968 dentry->d_inode->i_ctime = CURRENT_TIME_SEC; 969 mark_inode_dirty(dentry->d_inode); 970 971 out: 972 reiserfs_read_unlock_xattrs(dentry->d_sb); 973 reiserfs_write_unlock_xattr_i(dentry->d_inode); 974 return err; 975 } 976 977 /* This is what filldir will use: 978 * r_pos will always contain the amount of space required for the entire 979 * list. If r_pos becomes larger than r_size, we need more space and we 980 * return an error indicating this. If r_pos is less than r_size, then we've 981 * filled the buffer successfully and we return success */ 982 struct reiserfs_listxattr_buf { 983 int r_pos; 984 int r_size; 985 char *r_buf; 986 struct inode *r_inode; 987 }; 988 989 static int 990 reiserfs_listxattr_filler(void *buf, const char *name, int namelen, 991 loff_t offset, u64 ino, unsigned int d_type) 992 { 993 struct reiserfs_listxattr_buf *b = (struct reiserfs_listxattr_buf *)buf; 994 int len = 0; 995 if (name[0] != '.' 996 || (namelen != 1 && (name[1] != '.' || namelen != 2))) { 997 struct reiserfs_xattr_handler *xah = 998 find_xattr_handler_prefix(name); 999 if (!xah) 1000 return 0; /* Unsupported xattr name, skip it */ 1001 1002 /* We call ->list() twice because the operation isn't required to just 1003 * return the name back - we want to make sure we have enough space */ 1004 len += xah->list(b->r_inode, name, namelen, NULL); 1005 1006 if (len) { 1007 if (b->r_pos + len + 1 <= b->r_size) { 1008 char *p = b->r_buf + b->r_pos; 1009 p += xah->list(b->r_inode, name, namelen, p); 1010 *p++ = '\0'; 1011 } 1012 b->r_pos += len + 1; 1013 } 1014 } 1015 1016 return 0; 1017 } 1018 1019 /* 1020 * Inode operation listxattr() 1021 * 1022 * Preliminary locking: we down dentry->d_inode->i_mutex 1023 */ 1024 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 1025 { 1026 struct file *fp; 1027 struct dentry *dir; 1028 int err = 0; 1029 struct reiserfs_listxattr_buf buf; 1030 1031 if (!dentry->d_inode) 1032 return -EINVAL; 1033 1034 if (!reiserfs_xattrs(dentry->d_sb) || 1035 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 1036 return -EOPNOTSUPP; 1037 1038 reiserfs_read_lock_xattr_i(dentry->d_inode); 1039 reiserfs_read_lock_xattrs(dentry->d_sb); 1040 dir = open_xa_dir(dentry->d_inode, FL_READONLY); 1041 reiserfs_read_unlock_xattrs(dentry->d_sb); 1042 if (IS_ERR(dir)) { 1043 err = PTR_ERR(dir); 1044 if (err == -ENODATA) 1045 err = 0; /* Not an error if there aren't any xattrs */ 1046 goto out; 1047 } 1048 1049 fp = dentry_open(dir, NULL, O_RDWR); 1050 if (IS_ERR(fp)) { 1051 err = PTR_ERR(fp); 1052 /* dentry_open dputs the dentry if it fails */ 1053 goto out; 1054 } 1055 1056 buf.r_buf = buffer; 1057 buf.r_size = buffer ? size : 0; 1058 buf.r_pos = 0; 1059 buf.r_inode = dentry->d_inode; 1060 1061 REISERFS_I(dentry->d_inode)->i_flags |= i_has_xattr_dir; 1062 1063 err = xattr_readdir(fp, reiserfs_listxattr_filler, &buf); 1064 if (err) 1065 goto out_dir; 1066 1067 if (buf.r_pos > buf.r_size && buffer != NULL) 1068 err = -ERANGE; 1069 else 1070 err = buf.r_pos; 1071 1072 out_dir: 1073 fput(fp); 1074 1075 out: 1076 reiserfs_read_unlock_xattr_i(dentry->d_inode); 1077 return err; 1078 } 1079 1080 /* This is the implementation for the xattr plugin infrastructure */ 1081 static struct list_head xattr_handlers = LIST_HEAD_INIT(xattr_handlers); 1082 static DEFINE_RWLOCK(handler_lock); 1083 1084 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char 1085 *prefix) 1086 { 1087 struct reiserfs_xattr_handler *xah = NULL; 1088 struct list_head *p; 1089 1090 read_lock(&handler_lock); 1091 list_for_each(p, &xattr_handlers) { 1092 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1093 if (strncmp(xah->prefix, prefix, strlen(xah->prefix)) == 0) 1094 break; 1095 xah = NULL; 1096 } 1097 1098 read_unlock(&handler_lock); 1099 return xah; 1100 } 1101 1102 static void __unregister_handlers(void) 1103 { 1104 struct reiserfs_xattr_handler *xah; 1105 struct list_head *p, *tmp; 1106 1107 list_for_each_safe(p, tmp, &xattr_handlers) { 1108 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1109 if (xah->exit) 1110 xah->exit(); 1111 1112 list_del_init(p); 1113 } 1114 INIT_LIST_HEAD(&xattr_handlers); 1115 } 1116 1117 int __init reiserfs_xattr_register_handlers(void) 1118 { 1119 int err = 0; 1120 struct reiserfs_xattr_handler *xah; 1121 struct list_head *p; 1122 1123 write_lock(&handler_lock); 1124 1125 /* If we're already initialized, nothing to do */ 1126 if (!list_empty(&xattr_handlers)) { 1127 write_unlock(&handler_lock); 1128 return 0; 1129 } 1130 1131 /* Add the handlers */ 1132 list_add_tail(&user_handler.handlers, &xattr_handlers); 1133 list_add_tail(&trusted_handler.handlers, &xattr_handlers); 1134 #ifdef CONFIG_REISERFS_FS_SECURITY 1135 list_add_tail(&security_handler.handlers, &xattr_handlers); 1136 #endif 1137 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 1138 list_add_tail(&posix_acl_access_handler.handlers, &xattr_handlers); 1139 list_add_tail(&posix_acl_default_handler.handlers, &xattr_handlers); 1140 #endif 1141 1142 /* Run initializers, if available */ 1143 list_for_each(p, &xattr_handlers) { 1144 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1145 if (xah->init) { 1146 err = xah->init(); 1147 if (err) { 1148 list_del_init(p); 1149 break; 1150 } 1151 } 1152 } 1153 1154 /* Clean up other handlers, if any failed */ 1155 if (err) 1156 __unregister_handlers(); 1157 1158 write_unlock(&handler_lock); 1159 return err; 1160 } 1161 1162 void reiserfs_xattr_unregister_handlers(void) 1163 { 1164 write_lock(&handler_lock); 1165 __unregister_handlers(); 1166 write_unlock(&handler_lock); 1167 } 1168 1169 /* This will catch lookups from the fs root to .reiserfs_priv */ 1170 static int 1171 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 1172 { 1173 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 1174 if (name->len == priv_root->d_name.len && 1175 name->hash == priv_root->d_name.hash && 1176 !memcmp(name->name, priv_root->d_name.name, name->len)) { 1177 return -ENOENT; 1178 } else if (q1->len == name->len && 1179 !memcmp(q1->name, name->name, name->len)) 1180 return 0; 1181 return 1; 1182 } 1183 1184 static struct dentry_operations xattr_lookup_poison_ops = { 1185 .d_compare = xattr_lookup_poison, 1186 }; 1187 1188 /* We need to take a copy of the mount flags since things like 1189 * MS_RDONLY don't get set until *after* we're called. 1190 * mount_flags != mount_options */ 1191 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1192 { 1193 int err = 0; 1194 1195 /* We need generation numbers to ensure that the oid mapping is correct 1196 * v3.5 filesystems don't have them. */ 1197 if (!old_format_only(s)) { 1198 set_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1199 } else if (reiserfs_xattrs_optional(s)) { 1200 /* Old format filesystem, but optional xattrs have been enabled 1201 * at mount time. Error out. */ 1202 reiserfs_warning(s, "xattrs/ACLs not supported on pre v3.6 " 1203 "format filesystem. Failing mount."); 1204 err = -EOPNOTSUPP; 1205 goto error; 1206 } else { 1207 /* Old format filesystem, but no optional xattrs have been enabled. This 1208 * means we silently disable xattrs on the filesystem. */ 1209 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1210 } 1211 1212 /* If we don't have the privroot located yet - go find it */ 1213 if (reiserfs_xattrs(s) && !REISERFS_SB(s)->priv_root) { 1214 struct dentry *dentry; 1215 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 1216 strlen(PRIVROOT_NAME)); 1217 if (!IS_ERR(dentry)) { 1218 if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) { 1219 struct inode *inode = dentry->d_parent->d_inode; 1220 mutex_lock(&inode->i_mutex); 1221 err = inode->i_op->mkdir(inode, dentry, 0700); 1222 mutex_unlock(&inode->i_mutex); 1223 if (err) { 1224 dput(dentry); 1225 dentry = NULL; 1226 } 1227 1228 if (dentry && dentry->d_inode) 1229 reiserfs_warning(s, 1230 "Created %s on %s - reserved for " 1231 "xattr storage.", 1232 PRIVROOT_NAME, 1233 reiserfs_bdevname 1234 (inode->i_sb)); 1235 } else if (!dentry->d_inode) { 1236 dput(dentry); 1237 dentry = NULL; 1238 } 1239 } else 1240 err = PTR_ERR(dentry); 1241 1242 if (!err && dentry) { 1243 s->s_root->d_op = &xattr_lookup_poison_ops; 1244 reiserfs_mark_inode_private(dentry->d_inode); 1245 REISERFS_SB(s)->priv_root = dentry; 1246 } else if (!(mount_flags & MS_RDONLY)) { /* xattrs are unavailable */ 1247 /* If we're read-only it just means that the dir hasn't been 1248 * created. Not an error -- just no xattrs on the fs. We'll 1249 * check again if we go read-write */ 1250 reiserfs_warning(s, "xattrs/ACLs enabled and couldn't " 1251 "find/create .reiserfs_priv. Failing mount."); 1252 err = -EOPNOTSUPP; 1253 } 1254 } 1255 1256 error: 1257 /* This is only nonzero if there was an error initializing the xattr 1258 * directory or if there is a condition where we don't support them. */ 1259 if (err) { 1260 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1261 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1262 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1263 } 1264 1265 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1266 s->s_flags = s->s_flags & ~MS_POSIXACL; 1267 if (reiserfs_posixacl(s)) 1268 s->s_flags |= MS_POSIXACL; 1269 1270 return err; 1271 } 1272 1273 static int reiserfs_check_acl(struct inode *inode, int mask) 1274 { 1275 struct posix_acl *acl; 1276 int error = -EAGAIN; /* do regular unix permission checks by default */ 1277 1278 reiserfs_read_lock_xattr_i(inode); 1279 reiserfs_read_lock_xattrs(inode->i_sb); 1280 1281 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 1282 1283 reiserfs_read_unlock_xattrs(inode->i_sb); 1284 reiserfs_read_unlock_xattr_i(inode); 1285 1286 if (acl) { 1287 if (!IS_ERR(acl)) { 1288 error = posix_acl_permission(inode, acl, mask); 1289 posix_acl_release(acl); 1290 } else if (PTR_ERR(acl) != -ENODATA) 1291 error = PTR_ERR(acl); 1292 } 1293 1294 return error; 1295 } 1296 1297 int reiserfs_permission(struct inode *inode, int mask, struct nameidata *nd) 1298 { 1299 /* 1300 * We don't do permission checks on the internal objects. 1301 * Permissions are determined by the "owning" object. 1302 */ 1303 if (is_reiserfs_priv_object(inode)) 1304 return 0; 1305 1306 /* 1307 * Stat data v1 doesn't support ACLs. 1308 */ 1309 if (get_inode_sd_version(inode) == STAT_DATA_V1) 1310 return generic_permission(inode, mask, NULL); 1311 else 1312 return generic_permission(inode, mask, reiserfs_check_acl); 1313 } 1314