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 48 #define FL_READONLY 128 49 #define FL_DIR_SEM_HELD 256 50 #define PRIVROOT_NAME ".reiserfs_priv" 51 #define XAROOT_NAME "xattrs" 52 53 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char 54 *prefix); 55 56 /* Returns the dentry referring to the root of the extended attribute 57 * directory tree. If it has already been retrieved, it is used. If it 58 * hasn't been created and the flags indicate creation is allowed, we 59 * attempt to create it. On error, we return a pointer-encoded error. 60 */ 61 static struct dentry *get_xa_root(struct super_block *sb, int flags) 62 { 63 struct dentry *privroot = dget(REISERFS_SB(sb)->priv_root); 64 struct dentry *xaroot; 65 66 /* This needs to be created at mount-time */ 67 if (!privroot) 68 return ERR_PTR(-ENODATA); 69 70 mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR); 71 if (REISERFS_SB(sb)->xattr_root) { 72 xaroot = dget(REISERFS_SB(sb)->xattr_root); 73 goto out; 74 } 75 76 xaroot = lookup_one_len(XAROOT_NAME, privroot, strlen(XAROOT_NAME)); 77 if (IS_ERR(xaroot)) { 78 goto out; 79 } else if (!xaroot->d_inode) { 80 int err = -ENODATA; 81 if (flags == 0 || flags & XATTR_CREATE) 82 err = privroot->d_inode->i_op->mkdir(privroot->d_inode, 83 xaroot, 0700); 84 if (err) { 85 dput(xaroot); 86 xaroot = ERR_PTR(err); 87 goto out; 88 } 89 } 90 REISERFS_SB(sb)->xattr_root = dget(xaroot); 91 92 out: 93 mutex_unlock(&privroot->d_inode->i_mutex); 94 dput(privroot); 95 return xaroot; 96 } 97 98 /* Opens the directory corresponding to the inode's extended attribute store. 99 * If flags allow, the tree to the directory may be created. If creation is 100 * prohibited, -ENODATA is returned. */ 101 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 102 { 103 struct dentry *xaroot, *xadir; 104 char namebuf[17]; 105 106 xaroot = get_xa_root(inode->i_sb, flags); 107 if (IS_ERR(xaroot)) 108 return xaroot; 109 110 /* ok, we have xaroot open */ 111 snprintf(namebuf, sizeof(namebuf), "%X.%X", 112 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 113 inode->i_generation); 114 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); 115 if (IS_ERR(xadir)) { 116 dput(xaroot); 117 return xadir; 118 } 119 120 if (!xadir->d_inode) { 121 int err; 122 if (flags == 0 || flags & XATTR_CREATE) { 123 /* Although there is nothing else trying to create this directory, 124 * another directory with the same hash may be created, so we need 125 * to protect against that */ 126 err = 127 xaroot->d_inode->i_op->mkdir(xaroot->d_inode, xadir, 128 0700); 129 if (err) { 130 dput(xaroot); 131 dput(xadir); 132 return ERR_PTR(err); 133 } 134 } 135 if (!xadir->d_inode) { 136 dput(xaroot); 137 dput(xadir); 138 return ERR_PTR(-ENODATA); 139 } 140 } 141 142 dput(xaroot); 143 return xadir; 144 } 145 146 /* Returns a dentry corresponding to a specific extended attribute file 147 * for the inode. If flags allow, the file is created. Otherwise, a 148 * valid or negative dentry, or an error is returned. */ 149 static struct dentry *get_xa_file_dentry(const struct inode *inode, 150 const char *name, int flags) 151 { 152 struct dentry *xadir, *xafile; 153 int err = 0; 154 155 xadir = open_xa_dir(inode, flags); 156 if (IS_ERR(xadir)) { 157 return ERR_CAST(xadir); 158 } else if (!xadir->d_inode) { 159 dput(xadir); 160 return ERR_PTR(-ENODATA); 161 } 162 163 xafile = lookup_one_len(name, xadir, strlen(name)); 164 if (IS_ERR(xafile)) { 165 dput(xadir); 166 return ERR_CAST(xafile); 167 } 168 169 if (xafile->d_inode) { /* file exists */ 170 if (flags & XATTR_CREATE) { 171 err = -EEXIST; 172 dput(xafile); 173 goto out; 174 } 175 } else if (flags & XATTR_REPLACE || flags & FL_READONLY) { 176 goto out; 177 } else { 178 /* inode->i_mutex is down, so nothing else can try to create 179 * the same xattr */ 180 err = xadir->d_inode->i_op->create(xadir->d_inode, xafile, 181 0700 | S_IFREG, NULL); 182 183 if (err) { 184 dput(xafile); 185 goto out; 186 } 187 } 188 189 out: 190 dput(xadir); 191 if (err) 192 xafile = ERR_PTR(err); 193 else if (!xafile->d_inode) { 194 dput(xafile); 195 xafile = ERR_PTR(-ENODATA); 196 } 197 return xafile; 198 } 199 200 /* 201 * this is very similar to fs/reiserfs/dir.c:reiserfs_readdir, but 202 * we need to drop the path before calling the filldir struct. That 203 * would be a big performance hit to the non-xattr case, so I've copied 204 * the whole thing for now. --clm 205 * 206 * the big difference is that I go backwards through the directory, 207 * and don't mess with f->f_pos, but the idea is the same. Do some 208 * action on each and every entry in the directory. 209 * 210 * we're called with i_mutex held, so there are no worries about the directory 211 * changing underneath us. 212 */ 213 static int __xattr_readdir(struct inode *inode, void *dirent, filldir_t filldir) 214 { 215 struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */ 216 INITIALIZE_PATH(path_to_entry); 217 struct buffer_head *bh; 218 int entry_num; 219 struct item_head *ih, tmp_ih; 220 int search_res; 221 char *local_buf; 222 loff_t next_pos; 223 char small_buf[32]; /* avoid kmalloc if we can */ 224 struct reiserfs_de_head *deh; 225 int d_reclen; 226 char *d_name; 227 off_t d_off; 228 ino_t d_ino; 229 struct reiserfs_dir_entry de; 230 231 /* form key for search the next directory entry using f_pos field of 232 file structure */ 233 next_pos = max_reiserfs_offset(inode); 234 235 while (1) { 236 research: 237 if (next_pos <= DOT_DOT_OFFSET) 238 break; 239 make_cpu_key(&pos_key, inode, next_pos, TYPE_DIRENTRY, 3); 240 241 search_res = 242 search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry, 243 &de); 244 if (search_res == IO_ERROR) { 245 // FIXME: we could just skip part of directory which could 246 // not be read 247 pathrelse(&path_to_entry); 248 return -EIO; 249 } 250 251 if (search_res == NAME_NOT_FOUND) 252 de.de_entry_num--; 253 254 set_de_name_and_namelen(&de); 255 entry_num = de.de_entry_num; 256 deh = &(de.de_deh[entry_num]); 257 258 bh = de.de_bh; 259 ih = de.de_ih; 260 261 if (!is_direntry_le_ih(ih)) { 262 reiserfs_warning(inode->i_sb, "jdm-20000", 263 "not direntry %h", ih); 264 break; 265 } 266 copy_item_head(&tmp_ih, ih); 267 268 /* we must have found item, that is item of this directory, */ 269 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key), 270 "vs-9000: found item %h does not match to dir we readdir %K", 271 ih, &pos_key); 272 273 if (deh_offset(deh) <= DOT_DOT_OFFSET) { 274 break; 275 } 276 277 /* look for the previous entry in the directory */ 278 next_pos = deh_offset(deh) - 1; 279 280 if (!de_visible(deh)) 281 /* it is hidden entry */ 282 continue; 283 284 d_reclen = entry_length(bh, ih, entry_num); 285 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh); 286 d_off = deh_offset(deh); 287 d_ino = deh_objectid(deh); 288 289 if (!d_name[d_reclen - 1]) 290 d_reclen = strlen(d_name); 291 292 if (d_reclen > REISERFS_MAX_NAME(inode->i_sb->s_blocksize)) { 293 /* too big to send back to VFS */ 294 continue; 295 } 296 297 /* Ignore the .reiserfs_priv entry */ 298 if (reiserfs_xattrs(inode->i_sb) && 299 !old_format_only(inode->i_sb) && 300 deh_objectid(deh) == 301 le32_to_cpu(INODE_PKEY 302 (REISERFS_SB(inode->i_sb)->priv_root->d_inode)-> 303 k_objectid)) 304 continue; 305 306 if (d_reclen <= 32) { 307 local_buf = small_buf; 308 } else { 309 local_buf = kmalloc(d_reclen, GFP_NOFS); 310 if (!local_buf) { 311 pathrelse(&path_to_entry); 312 return -ENOMEM; 313 } 314 if (item_moved(&tmp_ih, &path_to_entry)) { 315 kfree(local_buf); 316 317 /* sigh, must retry. Do this same offset again */ 318 next_pos = d_off; 319 goto research; 320 } 321 } 322 323 // Note, that we copy name to user space via temporary 324 // buffer (local_buf) because filldir will block if 325 // user space buffer is swapped out. At that time 326 // entry can move to somewhere else 327 memcpy(local_buf, d_name, d_reclen); 328 329 /* the filldir function might need to start transactions, 330 * or do who knows what. Release the path now that we've 331 * copied all the important stuff out of the deh 332 */ 333 pathrelse(&path_to_entry); 334 335 if (filldir(dirent, local_buf, d_reclen, d_off, d_ino, 336 DT_UNKNOWN) < 0) { 337 if (local_buf != small_buf) { 338 kfree(local_buf); 339 } 340 goto end; 341 } 342 if (local_buf != small_buf) { 343 kfree(local_buf); 344 } 345 } /* while */ 346 347 end: 348 pathrelse(&path_to_entry); 349 return 0; 350 } 351 352 /* 353 * this could be done with dedicated readdir ops for the xattr files, 354 * but I want to get something working asap 355 * this is stolen from vfs_readdir 356 * 357 */ 358 static 359 int xattr_readdir(struct inode *inode, filldir_t filler, void *buf) 360 { 361 int res = -ENOENT; 362 mutex_lock_nested(&inode->i_mutex, I_MUTEX_XATTR); 363 if (!IS_DEADDIR(inode)) { 364 lock_kernel(); 365 res = __xattr_readdir(inode, buf, filler); 366 unlock_kernel(); 367 } 368 mutex_unlock(&inode->i_mutex); 369 return res; 370 } 371 372 /* Internal operations on file data */ 373 static inline void reiserfs_put_page(struct page *page) 374 { 375 kunmap(page); 376 page_cache_release(page); 377 } 378 379 static struct page *reiserfs_get_page(struct inode *dir, unsigned long n) 380 { 381 struct address_space *mapping = dir->i_mapping; 382 struct page *page; 383 /* We can deadlock if we try to free dentries, 384 and an unlink/rmdir has just occured - GFP_NOFS avoids this */ 385 mapping_set_gfp_mask(mapping, GFP_NOFS); 386 page = read_mapping_page(mapping, n, NULL); 387 if (!IS_ERR(page)) { 388 kmap(page); 389 if (PageError(page)) 390 goto fail; 391 } 392 return page; 393 394 fail: 395 reiserfs_put_page(page); 396 return ERR_PTR(-EIO); 397 } 398 399 static inline __u32 xattr_hash(const char *msg, int len) 400 { 401 return csum_partial(msg, len, 0); 402 } 403 404 int reiserfs_commit_write(struct file *f, struct page *page, 405 unsigned from, unsigned to); 406 int reiserfs_prepare_write(struct file *f, struct page *page, 407 unsigned from, unsigned to); 408 409 410 /* Generic extended attribute operations that can be used by xa plugins */ 411 412 /* 413 * inode->i_mutex: down 414 */ 415 int 416 reiserfs_xattr_set(struct inode *inode, const char *name, const void *buffer, 417 size_t buffer_size, int flags) 418 { 419 int err = 0; 420 struct dentry *dentry; 421 struct page *page; 422 char *data; 423 struct address_space *mapping; 424 size_t file_pos = 0; 425 size_t buffer_pos = 0; 426 struct inode *xinode; 427 struct iattr newattrs; 428 __u32 xahash = 0; 429 430 if (get_inode_sd_version(inode) == STAT_DATA_V1) 431 return -EOPNOTSUPP; 432 433 /* Empty xattrs are ok, they're just empty files, no hash */ 434 if (buffer && buffer_size) 435 xahash = xattr_hash(buffer, buffer_size); 436 437 open_file: 438 dentry = get_xa_file_dentry(inode, name, flags); 439 if (IS_ERR(dentry)) { 440 err = PTR_ERR(dentry); 441 goto out; 442 } 443 444 xinode = dentry->d_inode; 445 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 446 447 /* we need to copy it off.. */ 448 if (xinode->i_nlink > 1) { 449 dput(dentry); 450 err = reiserfs_xattr_del(inode, name); 451 if (err < 0) 452 goto out; 453 /* We just killed the old one, we're not replacing anymore */ 454 if (flags & XATTR_REPLACE) 455 flags &= ~XATTR_REPLACE; 456 goto open_file; 457 } 458 459 /* Resize it so we're ok to write there */ 460 newattrs.ia_size = buffer_size; 461 newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; 462 mutex_lock_nested(&xinode->i_mutex, I_MUTEX_XATTR); 463 err = notify_change(dentry, &newattrs); 464 if (err) 465 goto out_filp; 466 467 mapping = xinode->i_mapping; 468 while (buffer_pos < buffer_size || buffer_pos == 0) { 469 size_t chunk; 470 size_t skip = 0; 471 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 472 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 473 chunk = PAGE_CACHE_SIZE; 474 else 475 chunk = buffer_size - buffer_pos; 476 477 page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT); 478 if (IS_ERR(page)) { 479 err = PTR_ERR(page); 480 goto out_filp; 481 } 482 483 lock_page(page); 484 data = page_address(page); 485 486 if (file_pos == 0) { 487 struct reiserfs_xattr_header *rxh; 488 skip = file_pos = sizeof(struct reiserfs_xattr_header); 489 if (chunk + skip > PAGE_CACHE_SIZE) 490 chunk = PAGE_CACHE_SIZE - skip; 491 rxh = (struct reiserfs_xattr_header *)data; 492 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 493 rxh->h_hash = cpu_to_le32(xahash); 494 } 495 496 err = reiserfs_prepare_write(NULL, page, page_offset, 497 page_offset + chunk + skip); 498 if (!err) { 499 if (buffer) 500 memcpy(data + skip, buffer + buffer_pos, chunk); 501 err = reiserfs_commit_write(NULL, page, page_offset, 502 page_offset + chunk + 503 skip); 504 } 505 unlock_page(page); 506 reiserfs_put_page(page); 507 buffer_pos += chunk; 508 file_pos += chunk; 509 skip = 0; 510 if (err || buffer_size == 0 || !buffer) 511 break; 512 } 513 514 /* We can't mark the inode dirty if it's not hashed. This is the case 515 * when we're inheriting the default ACL. If we dirty it, the inode 516 * gets marked dirty, but won't (ever) make it onto the dirty list until 517 * it's synced explicitly to clear I_DIRTY. This is bad. */ 518 if (!hlist_unhashed(&inode->i_hash)) { 519 inode->i_ctime = CURRENT_TIME_SEC; 520 mark_inode_dirty(inode); 521 } 522 523 out_filp: 524 mutex_unlock(&xinode->i_mutex); 525 dput(dentry); 526 527 out: 528 return err; 529 } 530 531 /* 532 * inode->i_mutex: down 533 */ 534 int 535 reiserfs_xattr_get(const struct inode *inode, const char *name, void *buffer, 536 size_t buffer_size) 537 { 538 ssize_t err = 0; 539 struct dentry *dentry; 540 size_t isize; 541 size_t file_pos = 0; 542 size_t buffer_pos = 0; 543 struct page *page; 544 struct inode *xinode; 545 __u32 hash = 0; 546 547 if (name == NULL) 548 return -EINVAL; 549 550 /* We can't have xattrs attached to v1 items since they don't have 551 * generation numbers */ 552 if (get_inode_sd_version(inode) == STAT_DATA_V1) 553 return -EOPNOTSUPP; 554 555 dentry = get_xa_file_dentry(inode, name, FL_READONLY); 556 if (IS_ERR(dentry)) { 557 err = PTR_ERR(dentry); 558 goto out; 559 } 560 561 xinode = dentry->d_inode; 562 isize = xinode->i_size; 563 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 564 565 /* Just return the size needed */ 566 if (buffer == NULL) { 567 err = isize - sizeof(struct reiserfs_xattr_header); 568 goto out_dput; 569 } 570 571 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 572 err = -ERANGE; 573 goto out_dput; 574 } 575 576 while (file_pos < isize) { 577 size_t chunk; 578 char *data; 579 size_t skip = 0; 580 if (isize - file_pos > PAGE_CACHE_SIZE) 581 chunk = PAGE_CACHE_SIZE; 582 else 583 chunk = isize - file_pos; 584 585 page = reiserfs_get_page(xinode, file_pos >> PAGE_CACHE_SHIFT); 586 if (IS_ERR(page)) { 587 err = PTR_ERR(page); 588 goto out_dput; 589 } 590 591 lock_page(page); 592 data = page_address(page); 593 if (file_pos == 0) { 594 struct reiserfs_xattr_header *rxh = 595 (struct reiserfs_xattr_header *)data; 596 skip = file_pos = sizeof(struct reiserfs_xattr_header); 597 chunk -= skip; 598 /* Magic doesn't match up.. */ 599 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 600 unlock_page(page); 601 reiserfs_put_page(page); 602 reiserfs_warning(inode->i_sb, "jdm-20001", 603 "Invalid magic for xattr (%s) " 604 "associated with %k", name, 605 INODE_PKEY(inode)); 606 err = -EIO; 607 goto out_dput; 608 } 609 hash = le32_to_cpu(rxh->h_hash); 610 } 611 memcpy(buffer + buffer_pos, data + skip, chunk); 612 unlock_page(page); 613 reiserfs_put_page(page); 614 file_pos += chunk; 615 buffer_pos += chunk; 616 skip = 0; 617 } 618 err = isize - sizeof(struct reiserfs_xattr_header); 619 620 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 621 hash) { 622 reiserfs_warning(inode->i_sb, "jdm-20002", 623 "Invalid hash for xattr (%s) associated " 624 "with %k", name, INODE_PKEY(inode)); 625 err = -EIO; 626 } 627 628 out_dput: 629 dput(dentry); 630 631 out: 632 return err; 633 } 634 635 static int 636 __reiserfs_xattr_del(struct dentry *xadir, const char *name, int namelen) 637 { 638 struct dentry *dentry; 639 struct inode *dir = xadir->d_inode; 640 int err = 0; 641 642 dentry = lookup_one_len(name, xadir, namelen); 643 if (IS_ERR(dentry)) { 644 err = PTR_ERR(dentry); 645 goto out; 646 } else if (!dentry->d_inode) { 647 err = -ENODATA; 648 goto out_file; 649 } 650 651 /* Skip directories.. */ 652 if (S_ISDIR(dentry->d_inode->i_mode)) 653 goto out_file; 654 655 if (!is_reiserfs_priv_object(dentry->d_inode)) { 656 reiserfs_warning(dir->i_sb, "jdm-20003", 657 "OID %08x [%.*s/%.*s] doesn't have " 658 "priv flag set [parent is %sset].", 659 le32_to_cpu(INODE_PKEY(dentry->d_inode)-> 660 k_objectid), xadir->d_name.len, 661 xadir->d_name.name, namelen, name, 662 is_reiserfs_priv_object(xadir-> 663 d_inode) ? "" : 664 "not "); 665 dput(dentry); 666 return -EIO; 667 } 668 669 err = dir->i_op->unlink(dir, dentry); 670 if (!err) 671 d_delete(dentry); 672 673 out_file: 674 dput(dentry); 675 676 out: 677 return err; 678 } 679 680 int reiserfs_xattr_del(struct inode *inode, const char *name) 681 { 682 struct dentry *dir; 683 int err; 684 685 dir = open_xa_dir(inode, FL_READONLY); 686 if (IS_ERR(dir)) { 687 err = PTR_ERR(dir); 688 goto out; 689 } 690 691 err = __reiserfs_xattr_del(dir, name, strlen(name)); 692 dput(dir); 693 694 if (!err) { 695 inode->i_ctime = CURRENT_TIME_SEC; 696 mark_inode_dirty(inode); 697 } 698 699 out: 700 return err; 701 } 702 703 /* The following are side effects of other operations that aren't explicitly 704 * modifying extended attributes. This includes operations such as permissions 705 * or ownership changes, object deletions, etc. */ 706 707 static int 708 reiserfs_delete_xattrs_filler(void *buf, const char *name, int namelen, 709 loff_t offset, u64 ino, unsigned int d_type) 710 { 711 struct dentry *xadir = (struct dentry *)buf; 712 713 return __reiserfs_xattr_del(xadir, name, namelen); 714 715 } 716 717 /* This is called w/ inode->i_mutex downed */ 718 int reiserfs_delete_xattrs(struct inode *inode) 719 { 720 struct dentry *dir, *root; 721 int err = 0; 722 723 /* Skip out, an xattr has no xattrs associated with it */ 724 if (is_reiserfs_priv_object(inode) || 725 get_inode_sd_version(inode) == STAT_DATA_V1 || 726 !reiserfs_xattrs(inode->i_sb)) { 727 return 0; 728 } 729 reiserfs_read_lock_xattrs(inode->i_sb); 730 dir = open_xa_dir(inode, FL_READONLY); 731 reiserfs_read_unlock_xattrs(inode->i_sb); 732 if (IS_ERR(dir)) { 733 err = PTR_ERR(dir); 734 goto out; 735 } else if (!dir->d_inode) { 736 dput(dir); 737 return 0; 738 } 739 740 lock_kernel(); 741 err = xattr_readdir(dir->d_inode, reiserfs_delete_xattrs_filler, dir); 742 if (err) { 743 unlock_kernel(); 744 goto out_dir; 745 } 746 747 /* Leftovers besides . and .. -- that's not good. */ 748 if (dir->d_inode->i_nlink <= 2) { 749 root = get_xa_root(inode->i_sb, XATTR_REPLACE); 750 reiserfs_write_lock_xattrs(inode->i_sb); 751 err = vfs_rmdir(root->d_inode, dir); 752 reiserfs_write_unlock_xattrs(inode->i_sb); 753 dput(root); 754 } else { 755 reiserfs_warning(inode->i_sb, "jdm-20006", 756 "Couldn't remove all entries in directory"); 757 } 758 unlock_kernel(); 759 760 out_dir: 761 dput(dir); 762 763 out: 764 if (!err) 765 REISERFS_I(inode)->i_flags = 766 REISERFS_I(inode)->i_flags & ~i_has_xattr_dir; 767 return err; 768 } 769 770 struct reiserfs_chown_buf { 771 struct inode *inode; 772 struct dentry *xadir; 773 struct iattr *attrs; 774 }; 775 776 /* XXX: If there is a better way to do this, I'd love to hear about it */ 777 static int 778 reiserfs_chown_xattrs_filler(void *buf, const char *name, int namelen, 779 loff_t offset, u64 ino, unsigned int d_type) 780 { 781 struct reiserfs_chown_buf *chown_buf = (struct reiserfs_chown_buf *)buf; 782 struct dentry *xafile, *xadir = chown_buf->xadir; 783 struct iattr *attrs = chown_buf->attrs; 784 int err = 0; 785 786 xafile = lookup_one_len(name, xadir, namelen); 787 if (IS_ERR(xafile)) 788 return PTR_ERR(xafile); 789 else if (!xafile->d_inode) { 790 dput(xafile); 791 return -ENODATA; 792 } 793 794 if (!S_ISDIR(xafile->d_inode->i_mode)) 795 err = notify_change(xafile, attrs); 796 dput(xafile); 797 798 return err; 799 } 800 801 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 802 { 803 struct dentry *dir; 804 int err = 0; 805 struct reiserfs_chown_buf buf; 806 unsigned int ia_valid = attrs->ia_valid; 807 808 /* Skip out, an xattr has no xattrs associated with it */ 809 if (is_reiserfs_priv_object(inode) || 810 get_inode_sd_version(inode) == STAT_DATA_V1 || 811 !reiserfs_xattrs(inode->i_sb)) { 812 return 0; 813 } 814 reiserfs_read_lock_xattrs(inode->i_sb); 815 dir = open_xa_dir(inode, FL_READONLY); 816 reiserfs_read_unlock_xattrs(inode->i_sb); 817 if (IS_ERR(dir)) { 818 if (PTR_ERR(dir) != -ENODATA) 819 err = PTR_ERR(dir); 820 goto out; 821 } else if (!dir->d_inode) { 822 dput(dir); 823 goto out; 824 } 825 826 lock_kernel(); 827 828 attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME); 829 buf.xadir = dir; 830 buf.attrs = attrs; 831 buf.inode = inode; 832 833 err = xattr_readdir(dir->d_inode, reiserfs_chown_xattrs_filler, &buf); 834 if (err) { 835 unlock_kernel(); 836 goto out_dir; 837 } 838 839 err = notify_change(dir, attrs); 840 unlock_kernel(); 841 842 out_dir: 843 dput(dir); 844 845 out: 846 attrs->ia_valid = ia_valid; 847 return err; 848 } 849 850 /* Actual operations that are exported to VFS-land */ 851 852 /* 853 * Inode operation getxattr() 854 * Preliminary locking: we down dentry->d_inode->i_mutex 855 */ 856 ssize_t 857 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 858 size_t size) 859 { 860 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 861 int err; 862 863 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 864 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 865 return -EOPNOTSUPP; 866 867 reiserfs_read_lock_xattr_i(dentry->d_inode); 868 reiserfs_read_lock_xattrs(dentry->d_sb); 869 err = xah->get(dentry->d_inode, name, buffer, size); 870 reiserfs_read_unlock_xattrs(dentry->d_sb); 871 reiserfs_read_unlock_xattr_i(dentry->d_inode); 872 return err; 873 } 874 875 /* 876 * Inode operation setxattr() 877 * 878 * dentry->d_inode->i_mutex down 879 */ 880 int 881 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 882 size_t size, int flags) 883 { 884 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 885 int err; 886 int lock; 887 888 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 889 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 890 return -EOPNOTSUPP; 891 892 reiserfs_write_lock_xattr_i(dentry->d_inode); 893 lock = !has_xattr_dir(dentry->d_inode); 894 if (lock) 895 reiserfs_write_lock_xattrs(dentry->d_sb); 896 else 897 reiserfs_read_lock_xattrs(dentry->d_sb); 898 err = xah->set(dentry->d_inode, name, value, size, flags); 899 if (lock) 900 reiserfs_write_unlock_xattrs(dentry->d_sb); 901 else 902 reiserfs_read_unlock_xattrs(dentry->d_sb); 903 reiserfs_write_unlock_xattr_i(dentry->d_inode); 904 return err; 905 } 906 907 /* 908 * Inode operation removexattr() 909 * 910 * dentry->d_inode->i_mutex down 911 */ 912 int reiserfs_removexattr(struct dentry *dentry, const char *name) 913 { 914 int err; 915 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 916 917 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 918 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 919 return -EOPNOTSUPP; 920 921 reiserfs_write_lock_xattr_i(dentry->d_inode); 922 reiserfs_read_lock_xattrs(dentry->d_sb); 923 924 /* Deletion pre-operation */ 925 if (xah->del) { 926 err = xah->del(dentry->d_inode, name); 927 if (err) 928 goto out; 929 } 930 931 err = reiserfs_xattr_del(dentry->d_inode, name); 932 933 dentry->d_inode->i_ctime = CURRENT_TIME_SEC; 934 mark_inode_dirty(dentry->d_inode); 935 936 out: 937 reiserfs_read_unlock_xattrs(dentry->d_sb); 938 reiserfs_write_unlock_xattr_i(dentry->d_inode); 939 return err; 940 } 941 942 /* This is what filldir will use: 943 * r_pos will always contain the amount of space required for the entire 944 * list. If r_pos becomes larger than r_size, we need more space and we 945 * return an error indicating this. If r_pos is less than r_size, then we've 946 * filled the buffer successfully and we return success */ 947 struct reiserfs_listxattr_buf { 948 int r_pos; 949 int r_size; 950 char *r_buf; 951 struct inode *r_inode; 952 }; 953 954 static int 955 reiserfs_listxattr_filler(void *buf, const char *name, int namelen, 956 loff_t offset, u64 ino, unsigned int d_type) 957 { 958 struct reiserfs_listxattr_buf *b = (struct reiserfs_listxattr_buf *)buf; 959 int len = 0; 960 if (name[0] != '.' 961 || (namelen != 1 && (name[1] != '.' || namelen != 2))) { 962 struct reiserfs_xattr_handler *xah = 963 find_xattr_handler_prefix(name); 964 if (!xah) 965 return 0; /* Unsupported xattr name, skip it */ 966 967 /* We call ->list() twice because the operation isn't required to just 968 * return the name back - we want to make sure we have enough space */ 969 len += xah->list(b->r_inode, name, namelen, NULL); 970 971 if (len) { 972 if (b->r_pos + len + 1 <= b->r_size) { 973 char *p = b->r_buf + b->r_pos; 974 p += xah->list(b->r_inode, name, namelen, p); 975 *p++ = '\0'; 976 } 977 b->r_pos += len + 1; 978 } 979 } 980 981 return 0; 982 } 983 984 /* 985 * Inode operation listxattr() 986 * 987 * Preliminary locking: we down dentry->d_inode->i_mutex 988 */ 989 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 990 { 991 struct dentry *dir; 992 int err = 0; 993 struct reiserfs_listxattr_buf buf; 994 995 if (!dentry->d_inode) 996 return -EINVAL; 997 998 if (!reiserfs_xattrs(dentry->d_sb) || 999 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 1000 return -EOPNOTSUPP; 1001 1002 reiserfs_read_lock_xattr_i(dentry->d_inode); 1003 reiserfs_read_lock_xattrs(dentry->d_sb); 1004 dir = open_xa_dir(dentry->d_inode, FL_READONLY); 1005 reiserfs_read_unlock_xattrs(dentry->d_sb); 1006 if (IS_ERR(dir)) { 1007 err = PTR_ERR(dir); 1008 if (err == -ENODATA) 1009 err = 0; /* Not an error if there aren't any xattrs */ 1010 goto out; 1011 } 1012 1013 buf.r_buf = buffer; 1014 buf.r_size = buffer ? size : 0; 1015 buf.r_pos = 0; 1016 buf.r_inode = dentry->d_inode; 1017 1018 REISERFS_I(dentry->d_inode)->i_flags |= i_has_xattr_dir; 1019 1020 err = xattr_readdir(dir->d_inode, reiserfs_listxattr_filler, &buf); 1021 if (err) 1022 goto out_dir; 1023 1024 if (buf.r_pos > buf.r_size && buffer != NULL) 1025 err = -ERANGE; 1026 else 1027 err = buf.r_pos; 1028 1029 out_dir: 1030 dput(dir); 1031 1032 out: 1033 reiserfs_read_unlock_xattr_i(dentry->d_inode); 1034 return err; 1035 } 1036 1037 /* This is the implementation for the xattr plugin infrastructure */ 1038 static LIST_HEAD(xattr_handlers); 1039 static DEFINE_RWLOCK(handler_lock); 1040 1041 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char 1042 *prefix) 1043 { 1044 struct reiserfs_xattr_handler *xah = NULL; 1045 struct list_head *p; 1046 1047 read_lock(&handler_lock); 1048 list_for_each(p, &xattr_handlers) { 1049 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1050 if (strncmp(xah->prefix, prefix, strlen(xah->prefix)) == 0) 1051 break; 1052 xah = NULL; 1053 } 1054 1055 read_unlock(&handler_lock); 1056 return xah; 1057 } 1058 1059 static void __unregister_handlers(void) 1060 { 1061 struct reiserfs_xattr_handler *xah; 1062 struct list_head *p, *tmp; 1063 1064 list_for_each_safe(p, tmp, &xattr_handlers) { 1065 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1066 if (xah->exit) 1067 xah->exit(); 1068 1069 list_del_init(p); 1070 } 1071 INIT_LIST_HEAD(&xattr_handlers); 1072 } 1073 1074 int __init reiserfs_xattr_register_handlers(void) 1075 { 1076 int err = 0; 1077 struct reiserfs_xattr_handler *xah; 1078 struct list_head *p; 1079 1080 write_lock(&handler_lock); 1081 1082 /* If we're already initialized, nothing to do */ 1083 if (!list_empty(&xattr_handlers)) { 1084 write_unlock(&handler_lock); 1085 return 0; 1086 } 1087 1088 /* Add the handlers */ 1089 list_add_tail(&user_handler.handlers, &xattr_handlers); 1090 list_add_tail(&trusted_handler.handlers, &xattr_handlers); 1091 #ifdef CONFIG_REISERFS_FS_SECURITY 1092 list_add_tail(&security_handler.handlers, &xattr_handlers); 1093 #endif 1094 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 1095 list_add_tail(&posix_acl_access_handler.handlers, &xattr_handlers); 1096 list_add_tail(&posix_acl_default_handler.handlers, &xattr_handlers); 1097 #endif 1098 1099 /* Run initializers, if available */ 1100 list_for_each(p, &xattr_handlers) { 1101 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1102 if (xah->init) { 1103 err = xah->init(); 1104 if (err) { 1105 list_del_init(p); 1106 break; 1107 } 1108 } 1109 } 1110 1111 /* Clean up other handlers, if any failed */ 1112 if (err) 1113 __unregister_handlers(); 1114 1115 write_unlock(&handler_lock); 1116 return err; 1117 } 1118 1119 void reiserfs_xattr_unregister_handlers(void) 1120 { 1121 write_lock(&handler_lock); 1122 __unregister_handlers(); 1123 write_unlock(&handler_lock); 1124 } 1125 1126 /* This will catch lookups from the fs root to .reiserfs_priv */ 1127 static int 1128 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 1129 { 1130 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 1131 if (name->len == priv_root->d_name.len && 1132 name->hash == priv_root->d_name.hash && 1133 !memcmp(name->name, priv_root->d_name.name, name->len)) { 1134 return -ENOENT; 1135 } else if (q1->len == name->len && 1136 !memcmp(q1->name, name->name, name->len)) 1137 return 0; 1138 return 1; 1139 } 1140 1141 static struct dentry_operations xattr_lookup_poison_ops = { 1142 .d_compare = xattr_lookup_poison, 1143 }; 1144 1145 /* We need to take a copy of the mount flags since things like 1146 * MS_RDONLY don't get set until *after* we're called. 1147 * mount_flags != mount_options */ 1148 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1149 { 1150 int err = 0; 1151 1152 /* We need generation numbers to ensure that the oid mapping is correct 1153 * v3.5 filesystems don't have them. */ 1154 if (!old_format_only(s)) { 1155 set_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1156 } else if (reiserfs_xattrs_optional(s)) { 1157 /* Old format filesystem, but optional xattrs have been enabled 1158 * at mount time. Error out. */ 1159 reiserfs_warning(s, "jdm-20005", 1160 "xattrs/ACLs not supported on pre v3.6 " 1161 "format filesystem. Failing mount."); 1162 err = -EOPNOTSUPP; 1163 goto error; 1164 } else { 1165 /* Old format filesystem, but no optional xattrs have been enabled. This 1166 * means we silently disable xattrs on the filesystem. */ 1167 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1168 } 1169 1170 /* If we don't have the privroot located yet - go find it */ 1171 if (reiserfs_xattrs(s) && !REISERFS_SB(s)->priv_root) { 1172 struct dentry *dentry; 1173 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 1174 strlen(PRIVROOT_NAME)); 1175 if (!IS_ERR(dentry)) { 1176 if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) { 1177 struct inode *inode = dentry->d_parent->d_inode; 1178 mutex_lock_nested(&inode->i_mutex, 1179 I_MUTEX_XATTR); 1180 err = inode->i_op->mkdir(inode, dentry, 0700); 1181 mutex_unlock(&inode->i_mutex); 1182 if (err) { 1183 dput(dentry); 1184 dentry = NULL; 1185 } 1186 1187 if (dentry && dentry->d_inode) 1188 reiserfs_info(s, "Created %s - " 1189 "reserved for xattr " 1190 "storage.\n", 1191 PRIVROOT_NAME); 1192 } else if (!dentry->d_inode) { 1193 dput(dentry); 1194 dentry = NULL; 1195 } 1196 } else 1197 err = PTR_ERR(dentry); 1198 1199 if (!err && dentry) { 1200 s->s_root->d_op = &xattr_lookup_poison_ops; 1201 reiserfs_mark_inode_private(dentry->d_inode); 1202 REISERFS_SB(s)->priv_root = dentry; 1203 } else if (!(mount_flags & MS_RDONLY)) { /* xattrs are unavailable */ 1204 /* If we're read-only it just means that the dir hasn't been 1205 * created. Not an error -- just no xattrs on the fs. We'll 1206 * check again if we go read-write */ 1207 reiserfs_warning(s, "jdm-20006", 1208 "xattrs/ACLs enabled and couldn't " 1209 "find/create .reiserfs_priv. " 1210 "Failing mount."); 1211 err = -EOPNOTSUPP; 1212 } 1213 } 1214 1215 error: 1216 /* This is only nonzero if there was an error initializing the xattr 1217 * directory or if there is a condition where we don't support them. */ 1218 if (err) { 1219 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1220 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1221 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1222 } 1223 1224 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1225 s->s_flags = s->s_flags & ~MS_POSIXACL; 1226 if (reiserfs_posixacl(s)) 1227 s->s_flags |= MS_POSIXACL; 1228 1229 return err; 1230 } 1231 1232 static int reiserfs_check_acl(struct inode *inode, int mask) 1233 { 1234 struct posix_acl *acl; 1235 int error = -EAGAIN; /* do regular unix permission checks by default */ 1236 1237 reiserfs_read_lock_xattr_i(inode); 1238 reiserfs_read_lock_xattrs(inode->i_sb); 1239 1240 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 1241 1242 reiserfs_read_unlock_xattrs(inode->i_sb); 1243 reiserfs_read_unlock_xattr_i(inode); 1244 1245 if (acl) { 1246 if (!IS_ERR(acl)) { 1247 error = posix_acl_permission(inode, acl, mask); 1248 posix_acl_release(acl); 1249 } else if (PTR_ERR(acl) != -ENODATA) 1250 error = PTR_ERR(acl); 1251 } 1252 1253 return error; 1254 } 1255 1256 int reiserfs_permission(struct inode *inode, int mask) 1257 { 1258 /* 1259 * We don't do permission checks on the internal objects. 1260 * Permissions are determined by the "owning" object. 1261 */ 1262 if (is_reiserfs_priv_object(inode)) 1263 return 0; 1264 1265 /* 1266 * Stat data v1 doesn't support ACLs. 1267 */ 1268 if (get_inode_sd_version(inode) == STAT_DATA_V1) 1269 return generic_permission(inode, mask, NULL); 1270 else 1271 return generic_permission(inode, mask, reiserfs_check_acl); 1272 } 1273