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