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 * Locking works like so: 32 * The xattr root (/.reiserfs_priv/xattrs) is protected by its i_mutex. 33 * The xattr dir (/.reiserfs_priv/xattrs/<oid>.<gen>) is protected by 34 * inode->xattr_sem. 35 * The xattrs themselves are likewise protected by the xattr_sem. 36 */ 37 38 #include <linux/reiserfs_fs.h> 39 #include <linux/capability.h> 40 #include <linux/dcache.h> 41 #include <linux/namei.h> 42 #include <linux/errno.h> 43 #include <linux/fs.h> 44 #include <linux/file.h> 45 #include <linux/pagemap.h> 46 #include <linux/xattr.h> 47 #include <linux/reiserfs_xattr.h> 48 #include <linux/reiserfs_acl.h> 49 #include <asm/uaccess.h> 50 #include <net/checksum.h> 51 #include <linux/smp_lock.h> 52 #include <linux/stat.h> 53 #include <linux/quotaops.h> 54 55 #define PRIVROOT_NAME ".reiserfs_priv" 56 #define XAROOT_NAME "xattrs" 57 58 /* Helpers for inode ops. We do this so that we don't have all the VFS 59 * overhead and also for proper i_mutex annotation. 60 * dir->i_mutex must be held for all of them. */ 61 static int xattr_create(struct inode *dir, struct dentry *dentry, int mode) 62 { 63 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 64 DQUOT_INIT(dir); 65 return dir->i_op->create(dir, dentry, mode, NULL); 66 } 67 68 static int xattr_mkdir(struct inode *dir, struct dentry *dentry, int mode) 69 { 70 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 71 DQUOT_INIT(dir); 72 return dir->i_op->mkdir(dir, dentry, mode); 73 } 74 75 /* We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr 76 * mutation ops aren't called during rename or splace, which are the 77 * only other users of I_MUTEX_CHILD. It violates the ordering, but that's 78 * better than allocating another subclass just for this code. */ 79 static int xattr_unlink(struct inode *dir, struct dentry *dentry) 80 { 81 int error; 82 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 83 DQUOT_INIT(dir); 84 85 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); 86 error = dir->i_op->unlink(dir, dentry); 87 mutex_unlock(&dentry->d_inode->i_mutex); 88 89 if (!error) 90 d_delete(dentry); 91 return error; 92 } 93 94 static int xattr_rmdir(struct inode *dir, struct dentry *dentry) 95 { 96 int error; 97 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 98 DQUOT_INIT(dir); 99 100 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); 101 dentry_unhash(dentry); 102 error = dir->i_op->rmdir(dir, dentry); 103 if (!error) 104 dentry->d_inode->i_flags |= S_DEAD; 105 mutex_unlock(&dentry->d_inode->i_mutex); 106 if (!error) 107 d_delete(dentry); 108 dput(dentry); 109 110 return error; 111 } 112 113 114 #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE) 115 116 /* Returns and possibly creates the xattr dir. */ 117 static struct dentry *lookup_or_create_dir(struct dentry *parent, 118 const char *name, int flags) 119 { 120 struct dentry *dentry; 121 BUG_ON(!parent); 122 123 dentry = lookup_one_len(name, parent, strlen(name)); 124 if (IS_ERR(dentry)) 125 return dentry; 126 else if (!dentry->d_inode) { 127 int err = -ENODATA; 128 129 if (xattr_may_create(flags)) { 130 mutex_lock_nested(&parent->d_inode->i_mutex, 131 I_MUTEX_XATTR); 132 err = xattr_mkdir(parent->d_inode, dentry, 0700); 133 mutex_unlock(&parent->d_inode->i_mutex); 134 } 135 136 if (err) { 137 dput(dentry); 138 dentry = ERR_PTR(err); 139 } 140 } 141 142 return dentry; 143 } 144 145 static struct dentry *open_xa_root(struct super_block *sb, int flags) 146 { 147 struct dentry *privroot = REISERFS_SB(sb)->priv_root; 148 if (!privroot) 149 return ERR_PTR(-ENODATA); 150 return lookup_or_create_dir(privroot, XAROOT_NAME, flags); 151 } 152 153 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 154 { 155 struct dentry *xaroot, *xadir; 156 char namebuf[17]; 157 158 xaroot = open_xa_root(inode->i_sb, flags); 159 if (IS_ERR(xaroot)) 160 return xaroot; 161 162 snprintf(namebuf, sizeof(namebuf), "%X.%X", 163 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 164 inode->i_generation); 165 166 xadir = lookup_or_create_dir(xaroot, namebuf, flags); 167 dput(xaroot); 168 return xadir; 169 170 } 171 172 /* 173 * this is very similar to fs/reiserfs/dir.c:reiserfs_readdir, but 174 * we need to drop the path before calling the filldir struct. That 175 * would be a big performance hit to the non-xattr case, so I've copied 176 * the whole thing for now. --clm 177 * 178 * the big difference is that I go backwards through the directory, 179 * and don't mess with f->f_pos, but the idea is the same. Do some 180 * action on each and every entry in the directory. 181 * 182 * we're called with i_mutex held, so there are no worries about the directory 183 * changing underneath us. 184 */ 185 static int __xattr_readdir(struct inode *inode, void *dirent, filldir_t filldir) 186 { 187 struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */ 188 INITIALIZE_PATH(path_to_entry); 189 struct buffer_head *bh; 190 int entry_num; 191 struct item_head *ih, tmp_ih; 192 int search_res; 193 char *local_buf; 194 loff_t next_pos; 195 char small_buf[32]; /* avoid kmalloc if we can */ 196 struct reiserfs_de_head *deh; 197 int d_reclen; 198 char *d_name; 199 off_t d_off; 200 ino_t d_ino; 201 struct reiserfs_dir_entry de; 202 203 /* form key for search the next directory entry using f_pos field of 204 file structure */ 205 next_pos = max_reiserfs_offset(inode); 206 207 while (1) { 208 research: 209 if (next_pos <= DOT_DOT_OFFSET) 210 break; 211 make_cpu_key(&pos_key, inode, next_pos, TYPE_DIRENTRY, 3); 212 213 search_res = 214 search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry, 215 &de); 216 if (search_res == IO_ERROR) { 217 // FIXME: we could just skip part of directory which could 218 // not be read 219 pathrelse(&path_to_entry); 220 return -EIO; 221 } 222 223 if (search_res == NAME_NOT_FOUND) 224 de.de_entry_num--; 225 226 set_de_name_and_namelen(&de); 227 entry_num = de.de_entry_num; 228 deh = &(de.de_deh[entry_num]); 229 230 bh = de.de_bh; 231 ih = de.de_ih; 232 233 if (!is_direntry_le_ih(ih)) { 234 reiserfs_error(inode->i_sb, "jdm-20000", 235 "not direntry %h", ih); 236 break; 237 } 238 copy_item_head(&tmp_ih, ih); 239 240 /* we must have found item, that is item of this directory, */ 241 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key), 242 "vs-9000: found item %h does not match to dir we readdir %K", 243 ih, &pos_key); 244 245 if (deh_offset(deh) <= DOT_DOT_OFFSET) { 246 break; 247 } 248 249 /* look for the previous entry in the directory */ 250 next_pos = deh_offset(deh) - 1; 251 252 if (!de_visible(deh)) 253 /* it is hidden entry */ 254 continue; 255 256 d_reclen = entry_length(bh, ih, entry_num); 257 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh); 258 d_off = deh_offset(deh); 259 d_ino = deh_objectid(deh); 260 261 if (!d_name[d_reclen - 1]) 262 d_reclen = strlen(d_name); 263 264 if (d_reclen > REISERFS_MAX_NAME(inode->i_sb->s_blocksize)) { 265 /* too big to send back to VFS */ 266 continue; 267 } 268 269 /* Ignore the .reiserfs_priv entry */ 270 if (reiserfs_xattrs(inode->i_sb) && 271 !old_format_only(inode->i_sb) && 272 deh_objectid(deh) == 273 le32_to_cpu(INODE_PKEY 274 (REISERFS_SB(inode->i_sb)->priv_root->d_inode)-> 275 k_objectid)) 276 continue; 277 278 if (d_reclen <= 32) { 279 local_buf = small_buf; 280 } else { 281 local_buf = kmalloc(d_reclen, GFP_NOFS); 282 if (!local_buf) { 283 pathrelse(&path_to_entry); 284 return -ENOMEM; 285 } 286 if (item_moved(&tmp_ih, &path_to_entry)) { 287 kfree(local_buf); 288 289 /* sigh, must retry. Do this same offset again */ 290 next_pos = d_off; 291 goto research; 292 } 293 } 294 295 // Note, that we copy name to user space via temporary 296 // buffer (local_buf) because filldir will block if 297 // user space buffer is swapped out. At that time 298 // entry can move to somewhere else 299 memcpy(local_buf, d_name, d_reclen); 300 301 /* the filldir function might need to start transactions, 302 * or do who knows what. Release the path now that we've 303 * copied all the important stuff out of the deh 304 */ 305 pathrelse(&path_to_entry); 306 307 if (filldir(dirent, local_buf, d_reclen, d_off, d_ino, 308 DT_UNKNOWN) < 0) { 309 if (local_buf != small_buf) { 310 kfree(local_buf); 311 } 312 goto end; 313 } 314 if (local_buf != small_buf) { 315 kfree(local_buf); 316 } 317 } /* while */ 318 319 end: 320 pathrelse(&path_to_entry); 321 return 0; 322 } 323 324 /* 325 * this could be done with dedicated readdir ops for the xattr files, 326 * but I want to get something working asap 327 * this is stolen from vfs_readdir 328 * 329 */ 330 static 331 int xattr_readdir(struct inode *inode, filldir_t filler, void *buf) 332 { 333 int res = -ENOENT; 334 if (!IS_DEADDIR(inode)) { 335 lock_kernel(); 336 res = __xattr_readdir(inode, buf, filler); 337 unlock_kernel(); 338 } 339 return res; 340 } 341 342 static int 343 __reiserfs_xattr_del(struct dentry *xadir, const char *name, int namelen) 344 { 345 struct dentry *dentry; 346 struct inode *dir = xadir->d_inode; 347 int err = 0; 348 349 dentry = lookup_one_len(name, xadir, namelen); 350 if (IS_ERR(dentry)) { 351 err = PTR_ERR(dentry); 352 goto out; 353 } else if (!dentry->d_inode) { 354 err = -ENODATA; 355 goto out_file; 356 } 357 358 /* Skip directories.. */ 359 if (S_ISDIR(dentry->d_inode->i_mode)) 360 goto out_file; 361 362 if (!IS_PRIVATE(dentry->d_inode)) { 363 reiserfs_error(dir->i_sb, "jdm-20003", 364 "OID %08x [%.*s/%.*s] doesn't have " 365 "priv flag set [parent is %sset].", 366 le32_to_cpu(INODE_PKEY(dentry->d_inode)-> 367 k_objectid), xadir->d_name.len, 368 xadir->d_name.name, namelen, name, 369 IS_PRIVATE(xadir->d_inode) ? "" : 370 "not "); 371 dput(dentry); 372 return -EIO; 373 } 374 375 err = xattr_unlink(dir, dentry); 376 377 out_file: 378 dput(dentry); 379 380 out: 381 return err; 382 } 383 384 /* The following are side effects of other operations that aren't explicitly 385 * modifying extended attributes. This includes operations such as permissions 386 * or ownership changes, object deletions, etc. */ 387 388 static int 389 reiserfs_delete_xattrs_filler(void *buf, const char *name, int namelen, 390 loff_t offset, u64 ino, unsigned int d_type) 391 { 392 struct dentry *xadir = (struct dentry *)buf; 393 394 return __reiserfs_xattr_del(xadir, name, namelen); 395 396 } 397 398 /* This is called w/ inode->i_mutex downed */ 399 int reiserfs_delete_xattrs(struct inode *inode) 400 { 401 int err = 0; 402 struct dentry *dir, *root; 403 struct reiserfs_transaction_handle th; 404 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 405 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); 406 407 /* Skip out, an xattr has no xattrs associated with it */ 408 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 409 return 0; 410 411 dir = open_xa_dir(inode, XATTR_REPLACE); 412 if (IS_ERR(dir)) { 413 err = PTR_ERR(dir); 414 goto out; 415 } else if (!dir->d_inode) { 416 dput(dir); 417 return 0; 418 } 419 420 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 421 err = xattr_readdir(dir->d_inode, reiserfs_delete_xattrs_filler, dir); 422 mutex_unlock(&dir->d_inode->i_mutex); 423 if (err) 424 goto out_dir; 425 426 /* We start a transaction here to avoid a ABBA situation 427 * between the xattr root's i_mutex and the journal lock. 428 * Inode creation will inherit an ACL, which requires a 429 * lookup. The lookup locks the xattr root i_mutex with a 430 * transaction open. Inode deletion takes teh xattr root 431 * i_mutex to delete the directory and then starts a 432 * transaction inside it. Boom. This doesn't incur much 433 * additional overhead since the reiserfs_rmdir transaction 434 * will just nest inside the outer transaction. */ 435 err = journal_begin(&th, inode->i_sb, blocks); 436 if (!err) { 437 int jerror; 438 root = dget(dir->d_parent); 439 mutex_lock_nested(&root->d_inode->i_mutex, I_MUTEX_XATTR); 440 err = xattr_rmdir(root->d_inode, dir); 441 jerror = journal_end(&th, inode->i_sb, blocks); 442 mutex_unlock(&root->d_inode->i_mutex); 443 dput(root); 444 445 err = jerror ?: err; 446 } 447 448 out_dir: 449 dput(dir); 450 451 out: 452 if (!err) 453 REISERFS_I(inode)->i_flags = 454 REISERFS_I(inode)->i_flags & ~i_has_xattr_dir; 455 else 456 reiserfs_warning(inode->i_sb, "jdm-20004", 457 "Couldn't remove all xattrs (%d)\n", err); 458 return err; 459 } 460 461 struct reiserfs_chown_buf { 462 struct inode *inode; 463 struct dentry *xadir; 464 struct iattr *attrs; 465 }; 466 467 /* XXX: If there is a better way to do this, I'd love to hear about it */ 468 static int 469 reiserfs_chown_xattrs_filler(void *buf, const char *name, int namelen, 470 loff_t offset, u64 ino, unsigned int d_type) 471 { 472 struct reiserfs_chown_buf *chown_buf = (struct reiserfs_chown_buf *)buf; 473 struct dentry *xafile, *xadir = chown_buf->xadir; 474 struct iattr *attrs = chown_buf->attrs; 475 int err = 0; 476 477 xafile = lookup_one_len(name, xadir, namelen); 478 if (IS_ERR(xafile)) 479 return PTR_ERR(xafile); 480 else if (!xafile->d_inode) { 481 dput(xafile); 482 return -ENODATA; 483 } 484 485 if (!S_ISDIR(xafile->d_inode->i_mode)) { 486 mutex_lock_nested(&xafile->d_inode->i_mutex, I_MUTEX_CHILD); 487 err = notify_change(xafile, attrs); 488 mutex_unlock(&xafile->d_inode->i_mutex); 489 } 490 dput(xafile); 491 492 return err; 493 } 494 495 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 496 { 497 struct dentry *dir; 498 int err = 0; 499 struct reiserfs_chown_buf buf; 500 unsigned int ia_valid = attrs->ia_valid; 501 502 /* Skip out, an xattr has no xattrs associated with it */ 503 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 504 return 0; 505 506 dir = open_xa_dir(inode, XATTR_REPLACE); 507 if (IS_ERR(dir)) { 508 if (PTR_ERR(dir) != -ENODATA) 509 err = PTR_ERR(dir); 510 goto out; 511 } else if (!dir->d_inode) 512 goto out_dir; 513 514 attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME); 515 buf.xadir = dir; 516 buf.attrs = attrs; 517 buf.inode = inode; 518 519 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 520 err = xattr_readdir(dir->d_inode, reiserfs_chown_xattrs_filler, &buf); 521 522 if (!err) 523 err = notify_change(dir, attrs); 524 mutex_unlock(&dir->d_inode->i_mutex); 525 526 attrs->ia_valid = ia_valid; 527 out_dir: 528 dput(dir); 529 out: 530 return err; 531 } 532 533 #ifdef CONFIG_REISERFS_FS_XATTR 534 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char 535 *prefix); 536 537 /* Returns a dentry corresponding to a specific extended attribute file 538 * for the inode. If flags allow, the file is created. Otherwise, a 539 * valid or negative dentry, or an error is returned. */ 540 static struct dentry *get_xa_file_dentry(const struct inode *inode, 541 const char *name, int flags) 542 { 543 struct dentry *xadir, *xafile; 544 int err = 0; 545 546 xadir = open_xa_dir(inode, flags); 547 if (IS_ERR(xadir)) 548 return ERR_CAST(xadir); 549 550 xafile = lookup_one_len(name, xadir, strlen(name)); 551 if (IS_ERR(xafile)) { 552 err = PTR_ERR(xafile); 553 goto out; 554 } 555 556 if (xafile->d_inode && (flags & XATTR_CREATE)) 557 err = -EEXIST; 558 559 if (!xafile->d_inode) { 560 err = -ENODATA; 561 if (xattr_may_create(flags)) { 562 mutex_lock_nested(&xadir->d_inode->i_mutex, 563 I_MUTEX_XATTR); 564 err = xattr_create(xadir->d_inode, xafile, 565 0700|S_IFREG); 566 mutex_unlock(&xadir->d_inode->i_mutex); 567 } 568 } 569 570 if (err) 571 dput(xafile); 572 out: 573 dput(xadir); 574 if (err) 575 return ERR_PTR(err); 576 return xafile; 577 } 578 579 /* Internal operations on file data */ 580 static inline void reiserfs_put_page(struct page *page) 581 { 582 kunmap(page); 583 page_cache_release(page); 584 } 585 586 static struct page *reiserfs_get_page(struct inode *dir, size_t n) 587 { 588 struct address_space *mapping = dir->i_mapping; 589 struct page *page; 590 /* We can deadlock if we try to free dentries, 591 and an unlink/rmdir has just occured - GFP_NOFS avoids this */ 592 mapping_set_gfp_mask(mapping, GFP_NOFS); 593 page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); 594 if (!IS_ERR(page)) { 595 kmap(page); 596 if (PageError(page)) 597 goto fail; 598 } 599 return page; 600 601 fail: 602 reiserfs_put_page(page); 603 return ERR_PTR(-EIO); 604 } 605 606 static inline __u32 xattr_hash(const char *msg, int len) 607 { 608 return csum_partial(msg, len, 0); 609 } 610 611 int reiserfs_commit_write(struct file *f, struct page *page, 612 unsigned from, unsigned to); 613 int reiserfs_prepare_write(struct file *f, struct page *page, 614 unsigned from, unsigned to); 615 616 617 /* Generic extended attribute operations that can be used by xa plugins */ 618 619 /* 620 * inode->i_mutex: down 621 */ 622 int 623 reiserfs_xattr_set(struct inode *inode, const char *name, const void *buffer, 624 size_t buffer_size, int flags) 625 { 626 int err = 0; 627 struct dentry *dentry; 628 struct page *page; 629 char *data; 630 size_t file_pos = 0; 631 size_t buffer_pos = 0; 632 struct iattr newattrs; 633 __u32 xahash = 0; 634 635 if (get_inode_sd_version(inode) == STAT_DATA_V1) 636 return -EOPNOTSUPP; 637 638 /* Empty xattrs are ok, they're just empty files, no hash */ 639 if (buffer && buffer_size) 640 xahash = xattr_hash(buffer, buffer_size); 641 642 dentry = get_xa_file_dentry(inode, name, flags); 643 if (IS_ERR(dentry)) { 644 err = PTR_ERR(dentry); 645 goto out; 646 } 647 648 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 649 650 /* Resize it so we're ok to write there */ 651 newattrs.ia_size = buffer_size; 652 newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; 653 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 654 err = notify_change(dentry, &newattrs); 655 mutex_unlock(&dentry->d_inode->i_mutex); 656 if (err) 657 goto out_filp; 658 659 while (buffer_pos < buffer_size || buffer_pos == 0) { 660 size_t chunk; 661 size_t skip = 0; 662 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 663 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 664 chunk = PAGE_CACHE_SIZE; 665 else 666 chunk = buffer_size - buffer_pos; 667 668 page = reiserfs_get_page(dentry->d_inode, file_pos); 669 if (IS_ERR(page)) { 670 err = PTR_ERR(page); 671 goto out_filp; 672 } 673 674 lock_page(page); 675 data = page_address(page); 676 677 if (file_pos == 0) { 678 struct reiserfs_xattr_header *rxh; 679 skip = file_pos = sizeof(struct reiserfs_xattr_header); 680 if (chunk + skip > PAGE_CACHE_SIZE) 681 chunk = PAGE_CACHE_SIZE - skip; 682 rxh = (struct reiserfs_xattr_header *)data; 683 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 684 rxh->h_hash = cpu_to_le32(xahash); 685 } 686 687 err = reiserfs_prepare_write(NULL, page, page_offset, 688 page_offset + chunk + skip); 689 if (!err) { 690 if (buffer) 691 memcpy(data + skip, buffer + buffer_pos, chunk); 692 err = reiserfs_commit_write(NULL, page, page_offset, 693 page_offset + chunk + 694 skip); 695 } 696 unlock_page(page); 697 reiserfs_put_page(page); 698 buffer_pos += chunk; 699 file_pos += chunk; 700 skip = 0; 701 if (err || buffer_size == 0 || !buffer) 702 break; 703 } 704 705 /* We can't mark the inode dirty if it's not hashed. This is the case 706 * when we're inheriting the default ACL. If we dirty it, the inode 707 * gets marked dirty, but won't (ever) make it onto the dirty list until 708 * it's synced explicitly to clear I_DIRTY. This is bad. */ 709 if (!hlist_unhashed(&inode->i_hash)) { 710 inode->i_ctime = CURRENT_TIME_SEC; 711 mark_inode_dirty(inode); 712 } 713 714 out_filp: 715 dput(dentry); 716 717 out: 718 return err; 719 } 720 721 /* 722 * inode->i_mutex: down 723 */ 724 int 725 reiserfs_xattr_get(const struct inode *inode, const char *name, void *buffer, 726 size_t buffer_size) 727 { 728 ssize_t err = 0; 729 struct dentry *dentry; 730 size_t isize; 731 size_t file_pos = 0; 732 size_t buffer_pos = 0; 733 struct page *page; 734 __u32 hash = 0; 735 736 if (name == NULL) 737 return -EINVAL; 738 739 /* We can't have xattrs attached to v1 items since they don't have 740 * generation numbers */ 741 if (get_inode_sd_version(inode) == STAT_DATA_V1) 742 return -EOPNOTSUPP; 743 744 dentry = get_xa_file_dentry(inode, name, XATTR_REPLACE); 745 if (IS_ERR(dentry)) { 746 err = PTR_ERR(dentry); 747 goto out; 748 } 749 750 /* protect against concurrent access. xattrs are backed by 751 * regular files, but they're not regular files. The updates 752 * must be atomic from the perspective of the user. */ 753 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 754 755 isize = i_size_read(dentry->d_inode); 756 REISERFS_I(inode)->i_flags |= i_has_xattr_dir; 757 758 /* Just return the size needed */ 759 if (buffer == NULL) { 760 err = isize - sizeof(struct reiserfs_xattr_header); 761 goto out_dput; 762 } 763 764 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 765 err = -ERANGE; 766 goto out_dput; 767 } 768 769 while (file_pos < isize) { 770 size_t chunk; 771 char *data; 772 size_t skip = 0; 773 if (isize - file_pos > PAGE_CACHE_SIZE) 774 chunk = PAGE_CACHE_SIZE; 775 else 776 chunk = isize - file_pos; 777 778 page = reiserfs_get_page(dentry->d_inode, file_pos); 779 if (IS_ERR(page)) { 780 err = PTR_ERR(page); 781 goto out_dput; 782 } 783 784 lock_page(page); 785 data = page_address(page); 786 if (file_pos == 0) { 787 struct reiserfs_xattr_header *rxh = 788 (struct reiserfs_xattr_header *)data; 789 skip = file_pos = sizeof(struct reiserfs_xattr_header); 790 chunk -= skip; 791 /* Magic doesn't match up.. */ 792 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 793 unlock_page(page); 794 reiserfs_put_page(page); 795 reiserfs_warning(inode->i_sb, "jdm-20001", 796 "Invalid magic for xattr (%s) " 797 "associated with %k", name, 798 INODE_PKEY(inode)); 799 err = -EIO; 800 goto out_dput; 801 } 802 hash = le32_to_cpu(rxh->h_hash); 803 } 804 memcpy(buffer + buffer_pos, data + skip, chunk); 805 unlock_page(page); 806 reiserfs_put_page(page); 807 file_pos += chunk; 808 buffer_pos += chunk; 809 skip = 0; 810 } 811 err = isize - sizeof(struct reiserfs_xattr_header); 812 813 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 814 hash) { 815 reiserfs_warning(inode->i_sb, "jdm-20002", 816 "Invalid hash for xattr (%s) associated " 817 "with %k", name, INODE_PKEY(inode)); 818 err = -EIO; 819 } 820 821 out_dput: 822 mutex_unlock(&dentry->d_inode->i_mutex); 823 dput(dentry); 824 825 out: 826 return err; 827 } 828 829 int reiserfs_xattr_del(struct inode *inode, const char *name) 830 { 831 struct dentry *dir; 832 int err; 833 834 dir = open_xa_dir(inode, XATTR_REPLACE); 835 if (IS_ERR(dir)) { 836 err = PTR_ERR(dir); 837 goto out; 838 } 839 840 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 841 err = __reiserfs_xattr_del(dir, name, strlen(name)); 842 mutex_unlock(&dir->d_inode->i_mutex); 843 dput(dir); 844 845 if (!err) { 846 inode->i_ctime = CURRENT_TIME_SEC; 847 mark_inode_dirty(inode); 848 } 849 850 out: 851 return err; 852 } 853 854 /* Actual operations that are exported to VFS-land */ 855 856 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char *); 857 /* 858 * Inode operation getxattr() 859 */ 860 ssize_t 861 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 862 size_t size) 863 { 864 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 865 int err; 866 867 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 868 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 869 return -EOPNOTSUPP; 870 871 reiserfs_read_lock_xattr_i(dentry->d_inode); 872 err = xah->get(dentry->d_inode, name, buffer, size); 873 reiserfs_read_unlock_xattr_i(dentry->d_inode); 874 return err; 875 } 876 877 /* 878 * Inode operation setxattr() 879 * 880 * dentry->d_inode->i_mutex down 881 */ 882 int 883 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 884 size_t size, int flags) 885 { 886 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 887 int err; 888 889 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 890 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 891 return -EOPNOTSUPP; 892 893 reiserfs_write_lock_xattr_i(dentry->d_inode); 894 err = xah->set(dentry->d_inode, name, value, size, flags); 895 reiserfs_write_unlock_xattr_i(dentry->d_inode); 896 return err; 897 } 898 899 /* 900 * Inode operation removexattr() 901 * 902 * dentry->d_inode->i_mutex down 903 */ 904 int reiserfs_removexattr(struct dentry *dentry, const char *name) 905 { 906 int err; 907 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 908 909 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 910 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 911 return -EOPNOTSUPP; 912 913 reiserfs_write_lock_xattr_i(dentry->d_inode); 914 /* Deletion pre-operation */ 915 if (xah->del) { 916 err = xah->del(dentry->d_inode, name); 917 if (err) 918 goto out; 919 } 920 921 err = reiserfs_xattr_del(dentry->d_inode, name); 922 923 dentry->d_inode->i_ctime = CURRENT_TIME_SEC; 924 mark_inode_dirty(dentry->d_inode); 925 926 out: 927 reiserfs_write_unlock_xattr_i(dentry->d_inode); 928 return err; 929 } 930 931 /* This is what filldir will use: 932 * r_pos will always contain the amount of space required for the entire 933 * list. If r_pos becomes larger than r_size, we need more space and we 934 * return an error indicating this. If r_pos is less than r_size, then we've 935 * filled the buffer successfully and we return success */ 936 struct reiserfs_listxattr_buf { 937 int r_pos; 938 int r_size; 939 char *r_buf; 940 struct inode *r_inode; 941 }; 942 943 static int 944 reiserfs_listxattr_filler(void *buf, const char *name, int namelen, 945 loff_t offset, u64 ino, unsigned int d_type) 946 { 947 struct reiserfs_listxattr_buf *b = (struct reiserfs_listxattr_buf *)buf; 948 int len = 0; 949 if (name[0] != '.' 950 || (namelen != 1 && (name[1] != '.' || namelen != 2))) { 951 struct reiserfs_xattr_handler *xah = 952 find_xattr_handler_prefix(name); 953 if (!xah) 954 return 0; /* Unsupported xattr name, skip it */ 955 956 /* We call ->list() twice because the operation isn't required to just 957 * return the name back - we want to make sure we have enough space */ 958 len += xah->list(b->r_inode, name, namelen, NULL); 959 960 if (len) { 961 if (b->r_pos + len + 1 <= b->r_size) { 962 char *p = b->r_buf + b->r_pos; 963 p += xah->list(b->r_inode, name, namelen, p); 964 *p++ = '\0'; 965 } 966 b->r_pos += len + 1; 967 } 968 } 969 970 return 0; 971 } 972 973 /* 974 * Inode operation listxattr() 975 */ 976 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 977 { 978 struct dentry *dir; 979 int err = 0; 980 struct reiserfs_listxattr_buf buf; 981 982 if (!dentry->d_inode) 983 return -EINVAL; 984 985 if (!reiserfs_xattrs(dentry->d_sb) || 986 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 987 return -EOPNOTSUPP; 988 989 reiserfs_read_lock_xattr_i(dentry->d_inode); 990 dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); 991 if (IS_ERR(dir)) { 992 err = PTR_ERR(dir); 993 if (err == -ENODATA) 994 err = 0; /* Not an error if there aren't any xattrs */ 995 goto out; 996 } 997 998 buf.r_buf = buffer; 999 buf.r_size = buffer ? size : 0; 1000 buf.r_pos = 0; 1001 buf.r_inode = dentry->d_inode; 1002 1003 REISERFS_I(dentry->d_inode)->i_flags |= i_has_xattr_dir; 1004 1005 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 1006 err = xattr_readdir(dir->d_inode, reiserfs_listxattr_filler, &buf); 1007 mutex_unlock(&dir->d_inode->i_mutex); 1008 if (err) 1009 goto out_dir; 1010 1011 if (buf.r_pos > buf.r_size && buffer != NULL) 1012 err = -ERANGE; 1013 else 1014 err = buf.r_pos; 1015 1016 out_dir: 1017 dput(dir); 1018 1019 out: 1020 reiserfs_read_unlock_xattr_i(dentry->d_inode); 1021 return err; 1022 } 1023 1024 /* This is the implementation for the xattr plugin infrastructure */ 1025 static LIST_HEAD(xattr_handlers); 1026 static DEFINE_RWLOCK(handler_lock); 1027 1028 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char 1029 *prefix) 1030 { 1031 struct reiserfs_xattr_handler *xah = NULL; 1032 struct list_head *p; 1033 1034 read_lock(&handler_lock); 1035 list_for_each(p, &xattr_handlers) { 1036 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1037 if (strncmp(xah->prefix, prefix, strlen(xah->prefix)) == 0) 1038 break; 1039 xah = NULL; 1040 } 1041 1042 read_unlock(&handler_lock); 1043 return xah; 1044 } 1045 1046 static void __unregister_handlers(void) 1047 { 1048 struct reiserfs_xattr_handler *xah; 1049 struct list_head *p, *tmp; 1050 1051 list_for_each_safe(p, tmp, &xattr_handlers) { 1052 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1053 if (xah->exit) 1054 xah->exit(); 1055 1056 list_del_init(p); 1057 } 1058 INIT_LIST_HEAD(&xattr_handlers); 1059 } 1060 1061 int __init reiserfs_xattr_register_handlers(void) 1062 { 1063 int err = 0; 1064 struct reiserfs_xattr_handler *xah; 1065 struct list_head *p; 1066 1067 write_lock(&handler_lock); 1068 1069 /* If we're already initialized, nothing to do */ 1070 if (!list_empty(&xattr_handlers)) { 1071 write_unlock(&handler_lock); 1072 return 0; 1073 } 1074 1075 /* Add the handlers */ 1076 list_add_tail(&user_handler.handlers, &xattr_handlers); 1077 list_add_tail(&trusted_handler.handlers, &xattr_handlers); 1078 #ifdef CONFIG_REISERFS_FS_SECURITY 1079 list_add_tail(&security_handler.handlers, &xattr_handlers); 1080 #endif 1081 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 1082 list_add_tail(&posix_acl_access_handler.handlers, &xattr_handlers); 1083 list_add_tail(&posix_acl_default_handler.handlers, &xattr_handlers); 1084 #endif 1085 1086 /* Run initializers, if available */ 1087 list_for_each(p, &xattr_handlers) { 1088 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1089 if (xah->init) { 1090 err = xah->init(); 1091 if (err) { 1092 list_del_init(p); 1093 break; 1094 } 1095 } 1096 } 1097 1098 /* Clean up other handlers, if any failed */ 1099 if (err) 1100 __unregister_handlers(); 1101 1102 write_unlock(&handler_lock); 1103 return err; 1104 } 1105 1106 void reiserfs_xattr_unregister_handlers(void) 1107 { 1108 write_lock(&handler_lock); 1109 __unregister_handlers(); 1110 write_unlock(&handler_lock); 1111 } 1112 1113 static int reiserfs_check_acl(struct inode *inode, int mask) 1114 { 1115 struct posix_acl *acl; 1116 int error = -EAGAIN; /* do regular unix permission checks by default */ 1117 1118 reiserfs_read_lock_xattr_i(inode); 1119 1120 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 1121 1122 reiserfs_read_unlock_xattr_i(inode); 1123 1124 if (acl) { 1125 if (!IS_ERR(acl)) { 1126 error = posix_acl_permission(inode, acl, mask); 1127 posix_acl_release(acl); 1128 } else if (PTR_ERR(acl) != -ENODATA) 1129 error = PTR_ERR(acl); 1130 } 1131 1132 return error; 1133 } 1134 1135 int reiserfs_permission(struct inode *inode, int mask) 1136 { 1137 /* 1138 * We don't do permission checks on the internal objects. 1139 * Permissions are determined by the "owning" object. 1140 */ 1141 if (IS_PRIVATE(inode)) 1142 return 0; 1143 /* 1144 * Stat data v1 doesn't support ACLs. 1145 */ 1146 if (get_inode_sd_version(inode) == STAT_DATA_V1) 1147 return generic_permission(inode, mask, NULL); 1148 else 1149 return generic_permission(inode, mask, reiserfs_check_acl); 1150 } 1151 1152 static int create_privroot(struct dentry *dentry) 1153 { 1154 int err; 1155 struct inode *inode = dentry->d_parent->d_inode; 1156 mutex_lock_nested(&inode->i_mutex, I_MUTEX_XATTR); 1157 err = xattr_mkdir(inode, dentry, 0700); 1158 mutex_unlock(&inode->i_mutex); 1159 if (err) { 1160 dput(dentry); 1161 dentry = NULL; 1162 } 1163 1164 if (dentry && dentry->d_inode) 1165 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 1166 "storage.\n", PRIVROOT_NAME); 1167 1168 return err; 1169 } 1170 1171 static int xattr_mount_check(struct super_block *s) 1172 { 1173 /* We need generation numbers to ensure that the oid mapping is correct 1174 * v3.5 filesystems don't have them. */ 1175 if (!old_format_only(s)) { 1176 set_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1177 } else if (reiserfs_xattrs_optional(s)) { 1178 /* Old format filesystem, but optional xattrs have been enabled 1179 * at mount time. Error out. */ 1180 reiserfs_warning(s, "jdm-20005", 1181 "xattrs/ACLs not supported on pre v3.6 " 1182 "format filesystem. Failing mount."); 1183 return -EOPNOTSUPP; 1184 } else { 1185 /* Old format filesystem, but no optional xattrs have 1186 * been enabled. This means we silently disable xattrs 1187 * on the filesystem. */ 1188 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1189 } 1190 1191 return 0; 1192 } 1193 1194 #else 1195 int __init reiserfs_xattr_register_handlers(void) { return 0; } 1196 void reiserfs_xattr_unregister_handlers(void) {} 1197 #endif 1198 1199 /* This will catch lookups from the fs root to .reiserfs_priv */ 1200 static int 1201 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 1202 { 1203 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 1204 if (name->len == priv_root->d_name.len && 1205 name->hash == priv_root->d_name.hash && 1206 !memcmp(name->name, priv_root->d_name.name, name->len)) { 1207 return -ENOENT; 1208 } else if (q1->len == name->len && 1209 !memcmp(q1->name, name->name, name->len)) 1210 return 0; 1211 return 1; 1212 } 1213 1214 static struct dentry_operations xattr_lookup_poison_ops = { 1215 .d_compare = xattr_lookup_poison, 1216 }; 1217 1218 /* We need to take a copy of the mount flags since things like 1219 * MS_RDONLY don't get set until *after* we're called. 1220 * mount_flags != mount_options */ 1221 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1222 { 1223 int err = 0; 1224 1225 #ifdef CONFIG_REISERFS_FS_XATTR 1226 err = xattr_mount_check(s); 1227 if (err) 1228 goto error; 1229 #endif 1230 1231 /* If we don't have the privroot located yet - go find it */ 1232 if (!REISERFS_SB(s)->priv_root) { 1233 struct dentry *dentry; 1234 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 1235 strlen(PRIVROOT_NAME)); 1236 if (!IS_ERR(dentry)) { 1237 #ifdef CONFIG_REISERFS_FS_XATTR 1238 if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) 1239 err = create_privroot(dentry); 1240 #endif 1241 if (!dentry->d_inode) { 1242 dput(dentry); 1243 dentry = NULL; 1244 } 1245 } else 1246 err = PTR_ERR(dentry); 1247 1248 if (!err && dentry) { 1249 s->s_root->d_op = &xattr_lookup_poison_ops; 1250 dentry->d_inode->i_flags |= S_PRIVATE; 1251 REISERFS_SB(s)->priv_root = dentry; 1252 #ifdef CONFIG_REISERFS_FS_XATTR 1253 /* xattrs are unavailable */ 1254 } else if (!(mount_flags & MS_RDONLY)) { 1255 /* If we're read-only it just means that the dir 1256 * hasn't been created. Not an error -- just no 1257 * xattrs on the fs. We'll check again if we 1258 * go read-write */ 1259 reiserfs_warning(s, "jdm-20006", 1260 "xattrs/ACLs enabled and couldn't " 1261 "find/create .reiserfs_priv. " 1262 "Failing mount."); 1263 err = -EOPNOTSUPP; 1264 #endif 1265 } 1266 } 1267 1268 #ifdef CONFIG_REISERFS_FS_XATTR 1269 error: 1270 if (err) { 1271 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1272 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1273 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1274 } 1275 #endif 1276 1277 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1278 s->s_flags = s->s_flags & ~MS_POSIXACL; 1279 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 1280 if (reiserfs_posixacl(s)) 1281 s->s_flags |= MS_POSIXACL; 1282 #endif 1283 1284 return err; 1285 } 1286