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_error(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, size_t 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 >> PAGE_CACHE_SHIFT, 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 size_t file_pos = 0; 424 size_t buffer_pos = 0; 425 struct iattr newattrs; 426 __u32 xahash = 0; 427 428 if (get_inode_sd_version(inode) == STAT_DATA_V1) 429 return -EOPNOTSUPP; 430 431 /* Empty xattrs are ok, they're just empty files, no hash */ 432 if (buffer && buffer_size) 433 xahash = xattr_hash(buffer, buffer_size); 434 435 open_file: 436 dentry = get_xa_file_dentry(inode, name, flags); 437 if (IS_ERR(dentry)) { 438 err = PTR_ERR(dentry); 439 goto out; 440 } 441 442 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 443 444 /* we need to copy it off.. */ 445 if (dentry->d_inode->i_nlink > 1) { 446 dput(dentry); 447 err = reiserfs_xattr_del(inode, name); 448 if (err < 0) 449 goto out; 450 /* We just killed the old one, we're not replacing anymore */ 451 if (flags & XATTR_REPLACE) 452 flags &= ~XATTR_REPLACE; 453 goto open_file; 454 } 455 456 /* Resize it so we're ok to write there */ 457 newattrs.ia_size = buffer_size; 458 newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; 459 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 460 err = notify_change(dentry, &newattrs); 461 if (err) 462 goto out_filp; 463 464 while (buffer_pos < buffer_size || buffer_pos == 0) { 465 size_t chunk; 466 size_t skip = 0; 467 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 468 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 469 chunk = PAGE_CACHE_SIZE; 470 else 471 chunk = buffer_size - buffer_pos; 472 473 page = reiserfs_get_page(dentry->d_inode, file_pos); 474 if (IS_ERR(page)) { 475 err = PTR_ERR(page); 476 goto out_filp; 477 } 478 479 lock_page(page); 480 data = page_address(page); 481 482 if (file_pos == 0) { 483 struct reiserfs_xattr_header *rxh; 484 skip = file_pos = sizeof(struct reiserfs_xattr_header); 485 if (chunk + skip > PAGE_CACHE_SIZE) 486 chunk = PAGE_CACHE_SIZE - skip; 487 rxh = (struct reiserfs_xattr_header *)data; 488 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 489 rxh->h_hash = cpu_to_le32(xahash); 490 } 491 492 err = reiserfs_prepare_write(NULL, page, page_offset, 493 page_offset + chunk + skip); 494 if (!err) { 495 if (buffer) 496 memcpy(data + skip, buffer + buffer_pos, chunk); 497 err = reiserfs_commit_write(NULL, page, page_offset, 498 page_offset + chunk + 499 skip); 500 } 501 unlock_page(page); 502 reiserfs_put_page(page); 503 buffer_pos += chunk; 504 file_pos += chunk; 505 skip = 0; 506 if (err || buffer_size == 0 || !buffer) 507 break; 508 } 509 510 /* We can't mark the inode dirty if it's not hashed. This is the case 511 * when we're inheriting the default ACL. If we dirty it, the inode 512 * gets marked dirty, but won't (ever) make it onto the dirty list until 513 * it's synced explicitly to clear I_DIRTY. This is bad. */ 514 if (!hlist_unhashed(&inode->i_hash)) { 515 inode->i_ctime = CURRENT_TIME_SEC; 516 mark_inode_dirty(inode); 517 } 518 519 out_filp: 520 mutex_unlock(&dentry->d_inode->i_mutex); 521 dput(dentry); 522 523 out: 524 return err; 525 } 526 527 /* 528 * inode->i_mutex: down 529 */ 530 int 531 reiserfs_xattr_get(const struct inode *inode, const char *name, void *buffer, 532 size_t buffer_size) 533 { 534 ssize_t err = 0; 535 struct dentry *dentry; 536 size_t isize; 537 size_t file_pos = 0; 538 size_t buffer_pos = 0; 539 struct page *page; 540 __u32 hash = 0; 541 542 if (name == NULL) 543 return -EINVAL; 544 545 /* We can't have xattrs attached to v1 items since they don't have 546 * generation numbers */ 547 if (get_inode_sd_version(inode) == STAT_DATA_V1) 548 return -EOPNOTSUPP; 549 550 dentry = get_xa_file_dentry(inode, name, FL_READONLY); 551 if (IS_ERR(dentry)) { 552 err = PTR_ERR(dentry); 553 goto out; 554 } 555 556 isize = i_size_read(dentry->d_inode); 557 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 558 559 /* Just return the size needed */ 560 if (buffer == NULL) { 561 err = isize - sizeof(struct reiserfs_xattr_header); 562 goto out_dput; 563 } 564 565 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 566 err = -ERANGE; 567 goto out_dput; 568 } 569 570 while (file_pos < isize) { 571 size_t chunk; 572 char *data; 573 size_t skip = 0; 574 if (isize - file_pos > PAGE_CACHE_SIZE) 575 chunk = PAGE_CACHE_SIZE; 576 else 577 chunk = isize - file_pos; 578 579 page = reiserfs_get_page(dentry->d_inode, file_pos); 580 if (IS_ERR(page)) { 581 err = PTR_ERR(page); 582 goto out_dput; 583 } 584 585 lock_page(page); 586 data = page_address(page); 587 if (file_pos == 0) { 588 struct reiserfs_xattr_header *rxh = 589 (struct reiserfs_xattr_header *)data; 590 skip = file_pos = sizeof(struct reiserfs_xattr_header); 591 chunk -= skip; 592 /* Magic doesn't match up.. */ 593 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 594 unlock_page(page); 595 reiserfs_put_page(page); 596 reiserfs_warning(inode->i_sb, "jdm-20001", 597 "Invalid magic for xattr (%s) " 598 "associated with %k", name, 599 INODE_PKEY(inode)); 600 err = -EIO; 601 goto out_dput; 602 } 603 hash = le32_to_cpu(rxh->h_hash); 604 } 605 memcpy(buffer + buffer_pos, data + skip, chunk); 606 unlock_page(page); 607 reiserfs_put_page(page); 608 file_pos += chunk; 609 buffer_pos += chunk; 610 skip = 0; 611 } 612 err = isize - sizeof(struct reiserfs_xattr_header); 613 614 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 615 hash) { 616 reiserfs_warning(inode->i_sb, "jdm-20002", 617 "Invalid hash for xattr (%s) associated " 618 "with %k", name, INODE_PKEY(inode)); 619 err = -EIO; 620 } 621 622 out_dput: 623 dput(dentry); 624 625 out: 626 return err; 627 } 628 629 static int 630 __reiserfs_xattr_del(struct dentry *xadir, const char *name, int namelen) 631 { 632 struct dentry *dentry; 633 struct inode *dir = xadir->d_inode; 634 int err = 0; 635 636 dentry = lookup_one_len(name, xadir, namelen); 637 if (IS_ERR(dentry)) { 638 err = PTR_ERR(dentry); 639 goto out; 640 } else if (!dentry->d_inode) { 641 err = -ENODATA; 642 goto out_file; 643 } 644 645 /* Skip directories.. */ 646 if (S_ISDIR(dentry->d_inode->i_mode)) 647 goto out_file; 648 649 if (!is_reiserfs_priv_object(dentry->d_inode)) { 650 reiserfs_error(dir->i_sb, "jdm-20003", 651 "OID %08x [%.*s/%.*s] doesn't have " 652 "priv flag set [parent is %sset].", 653 le32_to_cpu(INODE_PKEY(dentry->d_inode)-> 654 k_objectid), xadir->d_name.len, 655 xadir->d_name.name, namelen, name, 656 is_reiserfs_priv_object(xadir->d_inode) ? "" : 657 "not "); 658 dput(dentry); 659 return -EIO; 660 } 661 662 err = dir->i_op->unlink(dir, dentry); 663 if (!err) 664 d_delete(dentry); 665 666 out_file: 667 dput(dentry); 668 669 out: 670 return err; 671 } 672 673 int reiserfs_xattr_del(struct inode *inode, const char *name) 674 { 675 struct dentry *dir; 676 int err; 677 678 dir = open_xa_dir(inode, FL_READONLY); 679 if (IS_ERR(dir)) { 680 err = PTR_ERR(dir); 681 goto out; 682 } 683 684 err = __reiserfs_xattr_del(dir, name, strlen(name)); 685 dput(dir); 686 687 if (!err) { 688 inode->i_ctime = CURRENT_TIME_SEC; 689 mark_inode_dirty(inode); 690 } 691 692 out: 693 return err; 694 } 695 696 /* The following are side effects of other operations that aren't explicitly 697 * modifying extended attributes. This includes operations such as permissions 698 * or ownership changes, object deletions, etc. */ 699 700 static int 701 reiserfs_delete_xattrs_filler(void *buf, const char *name, int namelen, 702 loff_t offset, u64 ino, unsigned int d_type) 703 { 704 struct dentry *xadir = (struct dentry *)buf; 705 706 return __reiserfs_xattr_del(xadir, name, namelen); 707 708 } 709 710 /* This is called w/ inode->i_mutex downed */ 711 int reiserfs_delete_xattrs(struct inode *inode) 712 { 713 struct dentry *dir, *root; 714 int err = 0; 715 716 /* Skip out, an xattr has no xattrs associated with it */ 717 if (is_reiserfs_priv_object(inode) || 718 get_inode_sd_version(inode) == STAT_DATA_V1 || 719 !reiserfs_xattrs(inode->i_sb)) { 720 return 0; 721 } 722 reiserfs_read_lock_xattrs(inode->i_sb); 723 dir = open_xa_dir(inode, FL_READONLY); 724 reiserfs_read_unlock_xattrs(inode->i_sb); 725 if (IS_ERR(dir)) { 726 err = PTR_ERR(dir); 727 goto out; 728 } else if (!dir->d_inode) { 729 dput(dir); 730 return 0; 731 } 732 733 lock_kernel(); 734 err = xattr_readdir(dir->d_inode, reiserfs_delete_xattrs_filler, dir); 735 if (err) { 736 unlock_kernel(); 737 goto out_dir; 738 } 739 740 /* Leftovers besides . and .. -- that's not good. */ 741 if (dir->d_inode->i_nlink <= 2) { 742 root = get_xa_root(inode->i_sb, XATTR_REPLACE); 743 reiserfs_write_lock_xattrs(inode->i_sb); 744 err = vfs_rmdir(root->d_inode, dir); 745 reiserfs_write_unlock_xattrs(inode->i_sb); 746 dput(root); 747 } else { 748 reiserfs_warning(inode->i_sb, "jdm-20006", 749 "Couldn't remove all entries in directory"); 750 } 751 unlock_kernel(); 752 753 out_dir: 754 dput(dir); 755 756 out: 757 if (!err) 758 REISERFS_I(inode)->i_flags = 759 REISERFS_I(inode)->i_flags & ~i_has_xattr_dir; 760 return err; 761 } 762 763 struct reiserfs_chown_buf { 764 struct inode *inode; 765 struct dentry *xadir; 766 struct iattr *attrs; 767 }; 768 769 /* XXX: If there is a better way to do this, I'd love to hear about it */ 770 static int 771 reiserfs_chown_xattrs_filler(void *buf, const char *name, int namelen, 772 loff_t offset, u64 ino, unsigned int d_type) 773 { 774 struct reiserfs_chown_buf *chown_buf = (struct reiserfs_chown_buf *)buf; 775 struct dentry *xafile, *xadir = chown_buf->xadir; 776 struct iattr *attrs = chown_buf->attrs; 777 int err = 0; 778 779 xafile = lookup_one_len(name, xadir, namelen); 780 if (IS_ERR(xafile)) 781 return PTR_ERR(xafile); 782 else if (!xafile->d_inode) { 783 dput(xafile); 784 return -ENODATA; 785 } 786 787 if (!S_ISDIR(xafile->d_inode->i_mode)) 788 err = notify_change(xafile, attrs); 789 dput(xafile); 790 791 return err; 792 } 793 794 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 795 { 796 struct dentry *dir; 797 int err = 0; 798 struct reiserfs_chown_buf buf; 799 unsigned int ia_valid = attrs->ia_valid; 800 801 /* Skip out, an xattr has no xattrs associated with it */ 802 if (is_reiserfs_priv_object(inode) || 803 get_inode_sd_version(inode) == STAT_DATA_V1 || 804 !reiserfs_xattrs(inode->i_sb)) { 805 return 0; 806 } 807 reiserfs_read_lock_xattrs(inode->i_sb); 808 dir = open_xa_dir(inode, FL_READONLY); 809 reiserfs_read_unlock_xattrs(inode->i_sb); 810 if (IS_ERR(dir)) { 811 if (PTR_ERR(dir) != -ENODATA) 812 err = PTR_ERR(dir); 813 goto out; 814 } else if (!dir->d_inode) { 815 dput(dir); 816 goto out; 817 } 818 819 lock_kernel(); 820 821 attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME); 822 buf.xadir = dir; 823 buf.attrs = attrs; 824 buf.inode = inode; 825 826 err = xattr_readdir(dir->d_inode, reiserfs_chown_xattrs_filler, &buf); 827 if (err) { 828 unlock_kernel(); 829 goto out_dir; 830 } 831 832 err = notify_change(dir, attrs); 833 unlock_kernel(); 834 835 out_dir: 836 dput(dir); 837 838 out: 839 attrs->ia_valid = ia_valid; 840 return err; 841 } 842 843 /* Actual operations that are exported to VFS-land */ 844 845 /* 846 * Inode operation getxattr() 847 * Preliminary locking: we down dentry->d_inode->i_mutex 848 */ 849 ssize_t 850 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 851 size_t size) 852 { 853 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 854 int err; 855 856 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 857 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 858 return -EOPNOTSUPP; 859 860 reiserfs_read_lock_xattr_i(dentry->d_inode); 861 reiserfs_read_lock_xattrs(dentry->d_sb); 862 err = xah->get(dentry->d_inode, name, buffer, size); 863 reiserfs_read_unlock_xattrs(dentry->d_sb); 864 reiserfs_read_unlock_xattr_i(dentry->d_inode); 865 return err; 866 } 867 868 /* 869 * Inode operation setxattr() 870 * 871 * dentry->d_inode->i_mutex down 872 */ 873 int 874 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 875 size_t size, int flags) 876 { 877 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 878 int err; 879 int lock; 880 881 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 882 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 883 return -EOPNOTSUPP; 884 885 reiserfs_write_lock_xattr_i(dentry->d_inode); 886 lock = !has_xattr_dir(dentry->d_inode); 887 if (lock) 888 reiserfs_write_lock_xattrs(dentry->d_sb); 889 else 890 reiserfs_read_lock_xattrs(dentry->d_sb); 891 err = xah->set(dentry->d_inode, name, value, size, flags); 892 if (lock) 893 reiserfs_write_unlock_xattrs(dentry->d_sb); 894 else 895 reiserfs_read_unlock_xattrs(dentry->d_sb); 896 reiserfs_write_unlock_xattr_i(dentry->d_inode); 897 return err; 898 } 899 900 /* 901 * Inode operation removexattr() 902 * 903 * dentry->d_inode->i_mutex down 904 */ 905 int reiserfs_removexattr(struct dentry *dentry, const char *name) 906 { 907 int err; 908 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 909 910 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 911 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 912 return -EOPNOTSUPP; 913 914 reiserfs_write_lock_xattr_i(dentry->d_inode); 915 reiserfs_read_lock_xattrs(dentry->d_sb); 916 917 /* Deletion pre-operation */ 918 if (xah->del) { 919 err = xah->del(dentry->d_inode, name); 920 if (err) 921 goto out; 922 } 923 924 err = reiserfs_xattr_del(dentry->d_inode, name); 925 926 dentry->d_inode->i_ctime = CURRENT_TIME_SEC; 927 mark_inode_dirty(dentry->d_inode); 928 929 out: 930 reiserfs_read_unlock_xattrs(dentry->d_sb); 931 reiserfs_write_unlock_xattr_i(dentry->d_inode); 932 return err; 933 } 934 935 /* This is what filldir will use: 936 * r_pos will always contain the amount of space required for the entire 937 * list. If r_pos becomes larger than r_size, we need more space and we 938 * return an error indicating this. If r_pos is less than r_size, then we've 939 * filled the buffer successfully and we return success */ 940 struct reiserfs_listxattr_buf { 941 int r_pos; 942 int r_size; 943 char *r_buf; 944 struct inode *r_inode; 945 }; 946 947 static int 948 reiserfs_listxattr_filler(void *buf, const char *name, int namelen, 949 loff_t offset, u64 ino, unsigned int d_type) 950 { 951 struct reiserfs_listxattr_buf *b = (struct reiserfs_listxattr_buf *)buf; 952 int len = 0; 953 if (name[0] != '.' 954 || (namelen != 1 && (name[1] != '.' || namelen != 2))) { 955 struct reiserfs_xattr_handler *xah = 956 find_xattr_handler_prefix(name); 957 if (!xah) 958 return 0; /* Unsupported xattr name, skip it */ 959 960 /* We call ->list() twice because the operation isn't required to just 961 * return the name back - we want to make sure we have enough space */ 962 len += xah->list(b->r_inode, name, namelen, NULL); 963 964 if (len) { 965 if (b->r_pos + len + 1 <= b->r_size) { 966 char *p = b->r_buf + b->r_pos; 967 p += xah->list(b->r_inode, name, namelen, p); 968 *p++ = '\0'; 969 } 970 b->r_pos += len + 1; 971 } 972 } 973 974 return 0; 975 } 976 977 /* 978 * Inode operation listxattr() 979 * 980 * Preliminary locking: we down dentry->d_inode->i_mutex 981 */ 982 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 983 { 984 struct dentry *dir; 985 int err = 0; 986 struct reiserfs_listxattr_buf buf; 987 988 if (!dentry->d_inode) 989 return -EINVAL; 990 991 if (!reiserfs_xattrs(dentry->d_sb) || 992 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 993 return -EOPNOTSUPP; 994 995 reiserfs_read_lock_xattr_i(dentry->d_inode); 996 reiserfs_read_lock_xattrs(dentry->d_sb); 997 dir = open_xa_dir(dentry->d_inode, FL_READONLY); 998 reiserfs_read_unlock_xattrs(dentry->d_sb); 999 if (IS_ERR(dir)) { 1000 err = PTR_ERR(dir); 1001 if (err == -ENODATA) 1002 err = 0; /* Not an error if there aren't any xattrs */ 1003 goto out; 1004 } 1005 1006 buf.r_buf = buffer; 1007 buf.r_size = buffer ? size : 0; 1008 buf.r_pos = 0; 1009 buf.r_inode = dentry->d_inode; 1010 1011 REISERFS_I(dentry->d_inode)->i_flags |= i_has_xattr_dir; 1012 1013 err = xattr_readdir(dir->d_inode, reiserfs_listxattr_filler, &buf); 1014 if (err) 1015 goto out_dir; 1016 1017 if (buf.r_pos > buf.r_size && buffer != NULL) 1018 err = -ERANGE; 1019 else 1020 err = buf.r_pos; 1021 1022 out_dir: 1023 dput(dir); 1024 1025 out: 1026 reiserfs_read_unlock_xattr_i(dentry->d_inode); 1027 return err; 1028 } 1029 1030 /* This is the implementation for the xattr plugin infrastructure */ 1031 static LIST_HEAD(xattr_handlers); 1032 static DEFINE_RWLOCK(handler_lock); 1033 1034 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char 1035 *prefix) 1036 { 1037 struct reiserfs_xattr_handler *xah = NULL; 1038 struct list_head *p; 1039 1040 read_lock(&handler_lock); 1041 list_for_each(p, &xattr_handlers) { 1042 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1043 if (strncmp(xah->prefix, prefix, strlen(xah->prefix)) == 0) 1044 break; 1045 xah = NULL; 1046 } 1047 1048 read_unlock(&handler_lock); 1049 return xah; 1050 } 1051 1052 static void __unregister_handlers(void) 1053 { 1054 struct reiserfs_xattr_handler *xah; 1055 struct list_head *p, *tmp; 1056 1057 list_for_each_safe(p, tmp, &xattr_handlers) { 1058 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1059 if (xah->exit) 1060 xah->exit(); 1061 1062 list_del_init(p); 1063 } 1064 INIT_LIST_HEAD(&xattr_handlers); 1065 } 1066 1067 int __init reiserfs_xattr_register_handlers(void) 1068 { 1069 int err = 0; 1070 struct reiserfs_xattr_handler *xah; 1071 struct list_head *p; 1072 1073 write_lock(&handler_lock); 1074 1075 /* If we're already initialized, nothing to do */ 1076 if (!list_empty(&xattr_handlers)) { 1077 write_unlock(&handler_lock); 1078 return 0; 1079 } 1080 1081 /* Add the handlers */ 1082 list_add_tail(&user_handler.handlers, &xattr_handlers); 1083 list_add_tail(&trusted_handler.handlers, &xattr_handlers); 1084 #ifdef CONFIG_REISERFS_FS_SECURITY 1085 list_add_tail(&security_handler.handlers, &xattr_handlers); 1086 #endif 1087 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 1088 list_add_tail(&posix_acl_access_handler.handlers, &xattr_handlers); 1089 list_add_tail(&posix_acl_default_handler.handlers, &xattr_handlers); 1090 #endif 1091 1092 /* Run initializers, if available */ 1093 list_for_each(p, &xattr_handlers) { 1094 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1095 if (xah->init) { 1096 err = xah->init(); 1097 if (err) { 1098 list_del_init(p); 1099 break; 1100 } 1101 } 1102 } 1103 1104 /* Clean up other handlers, if any failed */ 1105 if (err) 1106 __unregister_handlers(); 1107 1108 write_unlock(&handler_lock); 1109 return err; 1110 } 1111 1112 void reiserfs_xattr_unregister_handlers(void) 1113 { 1114 write_lock(&handler_lock); 1115 __unregister_handlers(); 1116 write_unlock(&handler_lock); 1117 } 1118 1119 /* This will catch lookups from the fs root to .reiserfs_priv */ 1120 static int 1121 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 1122 { 1123 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 1124 if (name->len == priv_root->d_name.len && 1125 name->hash == priv_root->d_name.hash && 1126 !memcmp(name->name, priv_root->d_name.name, name->len)) { 1127 return -ENOENT; 1128 } else if (q1->len == name->len && 1129 !memcmp(q1->name, name->name, name->len)) 1130 return 0; 1131 return 1; 1132 } 1133 1134 static struct dentry_operations xattr_lookup_poison_ops = { 1135 .d_compare = xattr_lookup_poison, 1136 }; 1137 1138 /* We need to take a copy of the mount flags since things like 1139 * MS_RDONLY don't get set until *after* we're called. 1140 * mount_flags != mount_options */ 1141 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1142 { 1143 int err = 0; 1144 1145 /* We need generation numbers to ensure that the oid mapping is correct 1146 * v3.5 filesystems don't have them. */ 1147 if (!old_format_only(s)) { 1148 set_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1149 } else if (reiserfs_xattrs_optional(s)) { 1150 /* Old format filesystem, but optional xattrs have been enabled 1151 * at mount time. Error out. */ 1152 reiserfs_warning(s, "jdm-20005", 1153 "xattrs/ACLs not supported on pre v3.6 " 1154 "format filesystem. Failing mount."); 1155 err = -EOPNOTSUPP; 1156 goto error; 1157 } else { 1158 /* Old format filesystem, but no optional xattrs have been enabled. This 1159 * means we silently disable xattrs on the filesystem. */ 1160 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1161 } 1162 1163 /* If we don't have the privroot located yet - go find it */ 1164 if (reiserfs_xattrs(s) && !REISERFS_SB(s)->priv_root) { 1165 struct dentry *dentry; 1166 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 1167 strlen(PRIVROOT_NAME)); 1168 if (!IS_ERR(dentry)) { 1169 if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) { 1170 struct inode *inode = dentry->d_parent->d_inode; 1171 mutex_lock_nested(&inode->i_mutex, 1172 I_MUTEX_XATTR); 1173 err = inode->i_op->mkdir(inode, dentry, 0700); 1174 mutex_unlock(&inode->i_mutex); 1175 if (err) { 1176 dput(dentry); 1177 dentry = NULL; 1178 } 1179 1180 if (dentry && dentry->d_inode) 1181 reiserfs_info(s, "Created %s - " 1182 "reserved for xattr " 1183 "storage.\n", 1184 PRIVROOT_NAME); 1185 } else if (!dentry->d_inode) { 1186 dput(dentry); 1187 dentry = NULL; 1188 } 1189 } else 1190 err = PTR_ERR(dentry); 1191 1192 if (!err && dentry) { 1193 s->s_root->d_op = &xattr_lookup_poison_ops; 1194 reiserfs_mark_inode_private(dentry->d_inode); 1195 REISERFS_SB(s)->priv_root = dentry; 1196 } else if (!(mount_flags & MS_RDONLY)) { /* xattrs are unavailable */ 1197 /* If we're read-only it just means that the dir hasn't been 1198 * created. Not an error -- just no xattrs on the fs. We'll 1199 * check again if we go read-write */ 1200 reiserfs_warning(s, "jdm-20006", 1201 "xattrs/ACLs enabled and couldn't " 1202 "find/create .reiserfs_priv. " 1203 "Failing mount."); 1204 err = -EOPNOTSUPP; 1205 } 1206 } 1207 1208 error: 1209 /* This is only nonzero if there was an error initializing the xattr 1210 * directory or if there is a condition where we don't support them. */ 1211 if (err) { 1212 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1213 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1214 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1215 } 1216 1217 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1218 s->s_flags = s->s_flags & ~MS_POSIXACL; 1219 if (reiserfs_posixacl(s)) 1220 s->s_flags |= MS_POSIXACL; 1221 1222 return err; 1223 } 1224 1225 static int reiserfs_check_acl(struct inode *inode, int mask) 1226 { 1227 struct posix_acl *acl; 1228 int error = -EAGAIN; /* do regular unix permission checks by default */ 1229 1230 reiserfs_read_lock_xattr_i(inode); 1231 reiserfs_read_lock_xattrs(inode->i_sb); 1232 1233 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 1234 1235 reiserfs_read_unlock_xattrs(inode->i_sb); 1236 reiserfs_read_unlock_xattr_i(inode); 1237 1238 if (acl) { 1239 if (!IS_ERR(acl)) { 1240 error = posix_acl_permission(inode, acl, mask); 1241 posix_acl_release(acl); 1242 } else if (PTR_ERR(acl) != -ENODATA) 1243 error = PTR_ERR(acl); 1244 } 1245 1246 return error; 1247 } 1248 1249 int reiserfs_permission(struct inode *inode, int mask) 1250 { 1251 /* 1252 * We don't do permission checks on the internal objects. 1253 * Permissions are determined by the "owning" object. 1254 */ 1255 if (is_reiserfs_priv_object(inode)) 1256 return 0; 1257 1258 /* 1259 * Stat data v1 doesn't support ACLs. 1260 */ 1261 if (get_inode_sd_version(inode) == STAT_DATA_V1) 1262 return generic_permission(inode, mask, NULL); 1263 else 1264 return generic_permission(inode, mask, reiserfs_check_acl); 1265 } 1266