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 * Directory components (xattr root, xattr dir) are protectd by their i_mutex. 33 * The xattrs themselves are protected by the xattr_sem. 34 */ 35 36 #include <linux/reiserfs_fs.h> 37 #include <linux/capability.h> 38 #include <linux/dcache.h> 39 #include <linux/namei.h> 40 #include <linux/errno.h> 41 #include <linux/fs.h> 42 #include <linux/file.h> 43 #include <linux/pagemap.h> 44 #include <linux/xattr.h> 45 #include <linux/reiserfs_xattr.h> 46 #include <linux/reiserfs_acl.h> 47 #include <asm/uaccess.h> 48 #include <net/checksum.h> 49 #include <linux/smp_lock.h> 50 #include <linux/stat.h> 51 #include <linux/quotaops.h> 52 53 #define PRIVROOT_NAME ".reiserfs_priv" 54 #define XAROOT_NAME "xattrs" 55 56 57 /* Helpers for inode ops. We do this so that we don't have all the VFS 58 * overhead and also for proper i_mutex annotation. 59 * dir->i_mutex must be held for all of them. */ 60 static int xattr_create(struct inode *dir, struct dentry *dentry, int mode) 61 { 62 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 63 DQUOT_INIT(dir); 64 return dir->i_op->create(dir, dentry, mode, NULL); 65 } 66 67 static int xattr_mkdir(struct inode *dir, struct dentry *dentry, int mode) 68 { 69 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 70 DQUOT_INIT(dir); 71 return dir->i_op->mkdir(dir, dentry, mode); 72 } 73 74 /* We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr 75 * mutation ops aren't called during rename or splace, which are the 76 * only other users of I_MUTEX_CHILD. It violates the ordering, but that's 77 * better than allocating another subclass just for this code. */ 78 static int xattr_unlink(struct inode *dir, struct dentry *dentry) 79 { 80 int error; 81 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 82 DQUOT_INIT(dir); 83 84 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); 85 error = dir->i_op->unlink(dir, dentry); 86 mutex_unlock(&dentry->d_inode->i_mutex); 87 88 if (!error) 89 d_delete(dentry); 90 return error; 91 } 92 93 static int xattr_rmdir(struct inode *dir, struct dentry *dentry) 94 { 95 int error; 96 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 97 DQUOT_INIT(dir); 98 99 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); 100 dentry_unhash(dentry); 101 error = dir->i_op->rmdir(dir, dentry); 102 if (!error) 103 dentry->d_inode->i_flags |= S_DEAD; 104 mutex_unlock(&dentry->d_inode->i_mutex); 105 if (!error) 106 d_delete(dentry); 107 dput(dentry); 108 109 return error; 110 } 111 112 #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE) 113 114 /* Returns and possibly creates the xattr dir. */ 115 static struct dentry *lookup_or_create_dir(struct dentry *parent, 116 const char *name, int flags) 117 { 118 struct dentry *dentry; 119 BUG_ON(!parent); 120 121 dentry = lookup_one_len(name, parent, strlen(name)); 122 if (IS_ERR(dentry)) 123 return dentry; 124 else if (!dentry->d_inode) { 125 int err = -ENODATA; 126 127 if (xattr_may_create(flags)) { 128 mutex_lock_nested(&parent->d_inode->i_mutex, 129 I_MUTEX_XATTR); 130 err = xattr_mkdir(parent->d_inode, dentry, 0700); 131 mutex_unlock(&parent->d_inode->i_mutex); 132 } 133 134 if (err) { 135 dput(dentry); 136 dentry = ERR_PTR(err); 137 } 138 } 139 140 return dentry; 141 } 142 143 static struct dentry *open_xa_root(struct super_block *sb, int flags) 144 { 145 struct dentry *privroot = REISERFS_SB(sb)->priv_root; 146 if (!privroot) 147 return ERR_PTR(-ENODATA); 148 return lookup_or_create_dir(privroot, XAROOT_NAME, flags); 149 } 150 151 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 152 { 153 struct dentry *xaroot, *xadir; 154 char namebuf[17]; 155 156 xaroot = open_xa_root(inode->i_sb, flags); 157 if (IS_ERR(xaroot)) 158 return xaroot; 159 160 snprintf(namebuf, sizeof(namebuf), "%X.%X", 161 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 162 inode->i_generation); 163 164 xadir = lookup_or_create_dir(xaroot, namebuf, flags); 165 dput(xaroot); 166 return xadir; 167 168 } 169 170 /* 171 * this is very similar to fs/reiserfs/dir.c:reiserfs_readdir, but 172 * we need to drop the path before calling the filldir struct. That 173 * would be a big performance hit to the non-xattr case, so I've copied 174 * the whole thing for now. --clm 175 * 176 * the big difference is that I go backwards through the directory, 177 * and don't mess with f->f_pos, but the idea is the same. Do some 178 * action on each and every entry in the directory. 179 * 180 * we're called with i_mutex held, so there are no worries about the directory 181 * changing underneath us. 182 */ 183 static int __xattr_readdir(struct inode *inode, void *dirent, filldir_t filldir) 184 { 185 struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */ 186 INITIALIZE_PATH(path_to_entry); 187 struct buffer_head *bh; 188 int entry_num; 189 struct item_head *ih, tmp_ih; 190 int search_res; 191 char *local_buf; 192 loff_t next_pos; 193 char small_buf[32]; /* avoid kmalloc if we can */ 194 struct reiserfs_de_head *deh; 195 int d_reclen; 196 char *d_name; 197 off_t d_off; 198 ino_t d_ino; 199 struct reiserfs_dir_entry de; 200 201 /* form key for search the next directory entry using f_pos field of 202 file structure */ 203 next_pos = max_reiserfs_offset(inode); 204 205 while (1) { 206 research: 207 if (next_pos <= DOT_DOT_OFFSET) 208 break; 209 make_cpu_key(&pos_key, inode, next_pos, TYPE_DIRENTRY, 3); 210 211 search_res = 212 search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry, 213 &de); 214 if (search_res == IO_ERROR) { 215 // FIXME: we could just skip part of directory which could 216 // not be read 217 pathrelse(&path_to_entry); 218 return -EIO; 219 } 220 221 if (search_res == NAME_NOT_FOUND) 222 de.de_entry_num--; 223 224 set_de_name_and_namelen(&de); 225 entry_num = de.de_entry_num; 226 deh = &(de.de_deh[entry_num]); 227 228 bh = de.de_bh; 229 ih = de.de_ih; 230 231 if (!is_direntry_le_ih(ih)) { 232 reiserfs_error(inode->i_sb, "jdm-20000", 233 "not direntry %h", ih); 234 break; 235 } 236 copy_item_head(&tmp_ih, ih); 237 238 /* we must have found item, that is item of this directory, */ 239 RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key), 240 "vs-9000: found item %h does not match to dir we readdir %K", 241 ih, &pos_key); 242 243 if (deh_offset(deh) <= DOT_DOT_OFFSET) { 244 break; 245 } 246 247 /* look for the previous entry in the directory */ 248 next_pos = deh_offset(deh) - 1; 249 250 if (!de_visible(deh)) 251 /* it is hidden entry */ 252 continue; 253 254 d_reclen = entry_length(bh, ih, entry_num); 255 d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh); 256 d_off = deh_offset(deh); 257 d_ino = deh_objectid(deh); 258 259 if (!d_name[d_reclen - 1]) 260 d_reclen = strlen(d_name); 261 262 if (d_reclen > REISERFS_MAX_NAME(inode->i_sb->s_blocksize)) { 263 /* too big to send back to VFS */ 264 continue; 265 } 266 267 /* Ignore the .reiserfs_priv entry */ 268 if (reiserfs_xattrs(inode->i_sb) && 269 !old_format_only(inode->i_sb) && 270 deh_objectid(deh) == 271 le32_to_cpu(INODE_PKEY 272 (REISERFS_SB(inode->i_sb)->priv_root->d_inode)-> 273 k_objectid)) 274 continue; 275 276 if (d_reclen <= 32) { 277 local_buf = small_buf; 278 } else { 279 local_buf = kmalloc(d_reclen, GFP_NOFS); 280 if (!local_buf) { 281 pathrelse(&path_to_entry); 282 return -ENOMEM; 283 } 284 if (item_moved(&tmp_ih, &path_to_entry)) { 285 kfree(local_buf); 286 287 /* sigh, must retry. Do this same offset again */ 288 next_pos = d_off; 289 goto research; 290 } 291 } 292 293 // Note, that we copy name to user space via temporary 294 // buffer (local_buf) because filldir will block if 295 // user space buffer is swapped out. At that time 296 // entry can move to somewhere else 297 memcpy(local_buf, d_name, d_reclen); 298 299 /* the filldir function might need to start transactions, 300 * or do who knows what. Release the path now that we've 301 * copied all the important stuff out of the deh 302 */ 303 pathrelse(&path_to_entry); 304 305 if (filldir(dirent, local_buf, d_reclen, d_off, d_ino, 306 DT_UNKNOWN) < 0) { 307 if (local_buf != small_buf) { 308 kfree(local_buf); 309 } 310 goto end; 311 } 312 if (local_buf != small_buf) { 313 kfree(local_buf); 314 } 315 } /* while */ 316 317 end: 318 pathrelse(&path_to_entry); 319 return 0; 320 } 321 322 /* 323 * this could be done with dedicated readdir ops for the xattr files, 324 * but I want to get something working asap 325 * this is stolen from vfs_readdir 326 * 327 */ 328 static 329 int xattr_readdir(struct inode *inode, filldir_t filler, void *buf) 330 { 331 int res = -ENOENT; 332 if (!IS_DEADDIR(inode)) { 333 lock_kernel(); 334 res = __xattr_readdir(inode, buf, filler); 335 unlock_kernel(); 336 } 337 return res; 338 } 339 340 /* The following are side effects of other operations that aren't explicitly 341 * modifying extended attributes. This includes operations such as permissions 342 * or ownership changes, object deletions, etc. */ 343 344 static int 345 reiserfs_delete_xattrs_filler(void *buf, const char *name, int namelen, 346 loff_t offset, u64 ino, unsigned int d_type) 347 { 348 struct dentry *xadir = (struct dentry *)buf; 349 struct dentry *dentry; 350 int err = 0; 351 352 dentry = lookup_one_len(name, xadir, namelen); 353 if (IS_ERR(dentry)) { 354 err = PTR_ERR(dentry); 355 goto out; 356 } else if (!dentry->d_inode) { 357 err = -ENODATA; 358 goto out_file; 359 } 360 361 /* Skip directories.. */ 362 if (S_ISDIR(dentry->d_inode->i_mode)) 363 goto out_file; 364 365 err = xattr_unlink(xadir->d_inode, dentry); 366 367 out_file: 368 dput(dentry); 369 370 out: 371 return err; 372 } 373 374 /* This is called w/ inode->i_mutex downed */ 375 int reiserfs_delete_xattrs(struct inode *inode) 376 { 377 int err = -ENODATA; 378 struct dentry *dir, *root; 379 struct reiserfs_transaction_handle th; 380 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 381 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); 382 383 /* Skip out, an xattr has no xattrs associated with it */ 384 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 385 return 0; 386 387 dir = open_xa_dir(inode, XATTR_REPLACE); 388 if (IS_ERR(dir)) { 389 err = PTR_ERR(dir); 390 goto out; 391 } else if (!dir->d_inode) { 392 dput(dir); 393 goto out; 394 } 395 396 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 397 err = xattr_readdir(dir->d_inode, reiserfs_delete_xattrs_filler, dir); 398 mutex_unlock(&dir->d_inode->i_mutex); 399 if (err) { 400 dput(dir); 401 goto out; 402 } 403 404 root = dget(dir->d_parent); 405 dput(dir); 406 407 /* We start a transaction here to avoid a ABBA situation 408 * between the xattr root's i_mutex and the journal lock. 409 * Inode creation will inherit an ACL, which requires a 410 * lookup. The lookup locks the xattr root i_mutex with a 411 * transaction open. Inode deletion takes teh xattr root 412 * i_mutex to delete the directory and then starts a 413 * transaction inside it. Boom. This doesn't incur much 414 * additional overhead since the reiserfs_rmdir transaction 415 * will just nest inside the outer transaction. */ 416 err = journal_begin(&th, inode->i_sb, blocks); 417 if (!err) { 418 int jerror; 419 mutex_lock_nested(&root->d_inode->i_mutex, I_MUTEX_XATTR); 420 err = xattr_rmdir(root->d_inode, dir); 421 jerror = journal_end(&th, inode->i_sb, blocks); 422 mutex_unlock(&root->d_inode->i_mutex); 423 err = jerror ?: err; 424 } 425 426 dput(root); 427 out: 428 if (err) 429 reiserfs_warning(inode->i_sb, "jdm-20004", 430 "Couldn't remove all xattrs (%d)\n", err); 431 return err; 432 } 433 434 struct reiserfs_chown_buf { 435 struct inode *inode; 436 struct dentry *xadir; 437 struct iattr *attrs; 438 }; 439 440 /* XXX: If there is a better way to do this, I'd love to hear about it */ 441 static int 442 reiserfs_chown_xattrs_filler(void *buf, const char *name, int namelen, 443 loff_t offset, u64 ino, unsigned int d_type) 444 { 445 struct reiserfs_chown_buf *chown_buf = (struct reiserfs_chown_buf *)buf; 446 struct dentry *xafile, *xadir = chown_buf->xadir; 447 struct iattr *attrs = chown_buf->attrs; 448 int err = 0; 449 450 xafile = lookup_one_len(name, xadir, namelen); 451 if (IS_ERR(xafile)) 452 return PTR_ERR(xafile); 453 else if (!xafile->d_inode) { 454 dput(xafile); 455 return -ENODATA; 456 } 457 458 if (!S_ISDIR(xafile->d_inode->i_mode)) { 459 mutex_lock_nested(&xafile->d_inode->i_mutex, I_MUTEX_CHILD); 460 err = reiserfs_setattr(xafile, attrs); 461 mutex_unlock(&xafile->d_inode->i_mutex); 462 } 463 dput(xafile); 464 465 return err; 466 } 467 468 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 469 { 470 struct dentry *dir; 471 int err = 0; 472 struct reiserfs_chown_buf buf; 473 unsigned int ia_valid = attrs->ia_valid; 474 475 /* Skip out, an xattr has no xattrs associated with it */ 476 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 477 return 0; 478 479 dir = open_xa_dir(inode, XATTR_REPLACE); 480 if (IS_ERR(dir)) { 481 if (PTR_ERR(dir) != -ENODATA) 482 err = PTR_ERR(dir); 483 goto out; 484 } else if (!dir->d_inode) 485 goto out_dir; 486 487 attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME); 488 buf.xadir = dir; 489 buf.attrs = attrs; 490 buf.inode = inode; 491 492 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 493 err = xattr_readdir(dir->d_inode, reiserfs_chown_xattrs_filler, &buf); 494 495 if (!err) 496 err = reiserfs_setattr(dir, attrs); 497 mutex_unlock(&dir->d_inode->i_mutex); 498 499 attrs->ia_valid = ia_valid; 500 out_dir: 501 dput(dir); 502 out: 503 if (err) 504 reiserfs_warning(inode->i_sb, "jdm-20007", 505 "Couldn't chown all xattrs (%d)\n", err); 506 return err; 507 } 508 509 #ifdef CONFIG_REISERFS_FS_XATTR 510 /* Returns a dentry corresponding to a specific extended attribute file 511 * for the inode. If flags allow, the file is created. Otherwise, a 512 * valid or negative dentry, or an error is returned. */ 513 static struct dentry *xattr_lookup(struct inode *inode, const char *name, 514 int flags) 515 { 516 struct dentry *xadir, *xafile; 517 int err = 0; 518 519 xadir = open_xa_dir(inode, flags); 520 if (IS_ERR(xadir)) 521 return ERR_CAST(xadir); 522 523 xafile = lookup_one_len(name, xadir, strlen(name)); 524 if (IS_ERR(xafile)) { 525 err = PTR_ERR(xafile); 526 goto out; 527 } 528 529 if (xafile->d_inode && (flags & XATTR_CREATE)) 530 err = -EEXIST; 531 532 if (!xafile->d_inode) { 533 err = -ENODATA; 534 if (xattr_may_create(flags)) { 535 mutex_lock_nested(&xadir->d_inode->i_mutex, 536 I_MUTEX_XATTR); 537 err = xattr_create(xadir->d_inode, xafile, 538 0700|S_IFREG); 539 mutex_unlock(&xadir->d_inode->i_mutex); 540 } 541 } 542 543 if (err) 544 dput(xafile); 545 out: 546 dput(xadir); 547 if (err) 548 return ERR_PTR(err); 549 return xafile; 550 } 551 552 /* Internal operations on file data */ 553 static inline void reiserfs_put_page(struct page *page) 554 { 555 kunmap(page); 556 page_cache_release(page); 557 } 558 559 static struct page *reiserfs_get_page(struct inode *dir, size_t n) 560 { 561 struct address_space *mapping = dir->i_mapping; 562 struct page *page; 563 /* We can deadlock if we try to free dentries, 564 and an unlink/rmdir has just occured - GFP_NOFS avoids this */ 565 mapping_set_gfp_mask(mapping, GFP_NOFS); 566 page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); 567 if (!IS_ERR(page)) { 568 kmap(page); 569 if (PageError(page)) 570 goto fail; 571 } 572 return page; 573 574 fail: 575 reiserfs_put_page(page); 576 return ERR_PTR(-EIO); 577 } 578 579 static inline __u32 xattr_hash(const char *msg, int len) 580 { 581 return csum_partial(msg, len, 0); 582 } 583 584 int reiserfs_commit_write(struct file *f, struct page *page, 585 unsigned from, unsigned to); 586 int reiserfs_prepare_write(struct file *f, struct page *page, 587 unsigned from, unsigned to); 588 589 static void update_ctime(struct inode *inode) 590 { 591 struct timespec now = current_fs_time(inode->i_sb); 592 if (hlist_unhashed(&inode->i_hash) || !inode->i_nlink || 593 timespec_equal(&inode->i_ctime, &now)) 594 return; 595 596 inode->i_ctime = CURRENT_TIME_SEC; 597 mark_inode_dirty(inode); 598 } 599 600 static int lookup_and_delete_xattr(struct inode *inode, const char *name) 601 { 602 int err = 0; 603 struct dentry *dentry, *xadir; 604 605 xadir = open_xa_dir(inode, XATTR_REPLACE); 606 if (IS_ERR(xadir)) 607 return PTR_ERR(xadir); 608 609 dentry = lookup_one_len(name, xadir, strlen(name)); 610 if (IS_ERR(dentry)) { 611 err = PTR_ERR(dentry); 612 goto out_dput; 613 } 614 615 if (dentry->d_inode) { 616 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 617 err = xattr_unlink(xadir->d_inode, dentry); 618 mutex_unlock(&xadir->d_inode->i_mutex); 619 update_ctime(inode); 620 } 621 622 dput(dentry); 623 out_dput: 624 dput(xadir); 625 return err; 626 } 627 628 629 /* Generic extended attribute operations that can be used by xa plugins */ 630 631 /* 632 * inode->i_mutex: down 633 */ 634 int 635 __reiserfs_xattr_set(struct inode *inode, const char *name, const void *buffer, 636 size_t buffer_size, int flags) 637 { 638 int err = 0; 639 struct dentry *dentry; 640 struct page *page; 641 char *data; 642 size_t file_pos = 0; 643 size_t buffer_pos = 0; 644 size_t new_size; 645 __u32 xahash = 0; 646 647 if (get_inode_sd_version(inode) == STAT_DATA_V1) 648 return -EOPNOTSUPP; 649 650 if (!buffer) 651 return lookup_and_delete_xattr(inode, name); 652 653 dentry = xattr_lookup(inode, name, flags); 654 if (IS_ERR(dentry)) 655 return PTR_ERR(dentry); 656 657 down_write(&REISERFS_I(inode)->i_xattr_sem); 658 659 xahash = xattr_hash(buffer, buffer_size); 660 while (buffer_pos < buffer_size || buffer_pos == 0) { 661 size_t chunk; 662 size_t skip = 0; 663 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 664 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 665 chunk = PAGE_CACHE_SIZE; 666 else 667 chunk = buffer_size - buffer_pos; 668 669 page = reiserfs_get_page(dentry->d_inode, file_pos); 670 if (IS_ERR(page)) { 671 err = PTR_ERR(page); 672 goto out_unlock; 673 } 674 675 lock_page(page); 676 data = page_address(page); 677 678 if (file_pos == 0) { 679 struct reiserfs_xattr_header *rxh; 680 skip = file_pos = sizeof(struct reiserfs_xattr_header); 681 if (chunk + skip > PAGE_CACHE_SIZE) 682 chunk = PAGE_CACHE_SIZE - skip; 683 rxh = (struct reiserfs_xattr_header *)data; 684 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 685 rxh->h_hash = cpu_to_le32(xahash); 686 } 687 688 err = reiserfs_prepare_write(NULL, page, page_offset, 689 page_offset + chunk + skip); 690 if (!err) { 691 if (buffer) 692 memcpy(data + skip, buffer + buffer_pos, chunk); 693 err = reiserfs_commit_write(NULL, page, page_offset, 694 page_offset + chunk + 695 skip); 696 } 697 unlock_page(page); 698 reiserfs_put_page(page); 699 buffer_pos += chunk; 700 file_pos += chunk; 701 skip = 0; 702 if (err || buffer_size == 0 || !buffer) 703 break; 704 } 705 706 new_size = buffer_size + sizeof(struct reiserfs_xattr_header); 707 if (!err && new_size < i_size_read(dentry->d_inode)) { 708 struct iattr newattrs = { 709 .ia_ctime = current_fs_time(inode->i_sb), 710 .ia_size = buffer_size, 711 .ia_valid = ATTR_SIZE | ATTR_CTIME, 712 }; 713 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 714 down_write(&dentry->d_inode->i_alloc_sem); 715 err = reiserfs_setattr(dentry, &newattrs); 716 up_write(&dentry->d_inode->i_alloc_sem); 717 mutex_unlock(&dentry->d_inode->i_mutex); 718 } else 719 update_ctime(inode); 720 out_unlock: 721 up_write(&REISERFS_I(inode)->i_xattr_sem); 722 dput(dentry); 723 return err; 724 } 725 726 int 727 reiserfs_xattr_set(struct inode *inode, const char *name, const void *buffer, 728 size_t buffer_size, int flags) 729 { 730 int err = __reiserfs_xattr_set(inode, name, buffer, buffer_size, flags); 731 if (err == -ENODATA) 732 err = 0; 733 return err; 734 } 735 736 /* 737 * inode->i_mutex: down 738 */ 739 int 740 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, 741 size_t buffer_size) 742 { 743 ssize_t err = 0; 744 struct dentry *dentry; 745 size_t isize; 746 size_t file_pos = 0; 747 size_t buffer_pos = 0; 748 struct page *page; 749 __u32 hash = 0; 750 751 if (name == NULL) 752 return -EINVAL; 753 754 /* We can't have xattrs attached to v1 items since they don't have 755 * generation numbers */ 756 if (get_inode_sd_version(inode) == STAT_DATA_V1) 757 return -EOPNOTSUPP; 758 759 dentry = xattr_lookup(inode, name, XATTR_REPLACE); 760 if (IS_ERR(dentry)) { 761 err = PTR_ERR(dentry); 762 goto out; 763 } 764 765 down_read(&REISERFS_I(inode)->i_xattr_sem); 766 767 isize = i_size_read(dentry->d_inode); 768 769 /* Just return the size needed */ 770 if (buffer == NULL) { 771 err = isize - sizeof(struct reiserfs_xattr_header); 772 goto out_unlock; 773 } 774 775 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 776 err = -ERANGE; 777 goto out_unlock; 778 } 779 780 while (file_pos < isize) { 781 size_t chunk; 782 char *data; 783 size_t skip = 0; 784 if (isize - file_pos > PAGE_CACHE_SIZE) 785 chunk = PAGE_CACHE_SIZE; 786 else 787 chunk = isize - file_pos; 788 789 page = reiserfs_get_page(dentry->d_inode, file_pos); 790 if (IS_ERR(page)) { 791 err = PTR_ERR(page); 792 goto out_unlock; 793 } 794 795 lock_page(page); 796 data = page_address(page); 797 if (file_pos == 0) { 798 struct reiserfs_xattr_header *rxh = 799 (struct reiserfs_xattr_header *)data; 800 skip = file_pos = sizeof(struct reiserfs_xattr_header); 801 chunk -= skip; 802 /* Magic doesn't match up.. */ 803 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 804 unlock_page(page); 805 reiserfs_put_page(page); 806 reiserfs_warning(inode->i_sb, "jdm-20001", 807 "Invalid magic for xattr (%s) " 808 "associated with %k", name, 809 INODE_PKEY(inode)); 810 err = -EIO; 811 goto out_unlock; 812 } 813 hash = le32_to_cpu(rxh->h_hash); 814 } 815 memcpy(buffer + buffer_pos, data + skip, chunk); 816 unlock_page(page); 817 reiserfs_put_page(page); 818 file_pos += chunk; 819 buffer_pos += chunk; 820 skip = 0; 821 } 822 err = isize - sizeof(struct reiserfs_xattr_header); 823 824 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 825 hash) { 826 reiserfs_warning(inode->i_sb, "jdm-20002", 827 "Invalid hash for xattr (%s) associated " 828 "with %k", name, INODE_PKEY(inode)); 829 err = -EIO; 830 } 831 832 out_unlock: 833 up_read(&REISERFS_I(inode)->i_xattr_sem); 834 dput(dentry); 835 836 out: 837 return err; 838 } 839 840 /* Actual operations that are exported to VFS-land */ 841 struct xattr_handler *reiserfs_xattr_handlers[] = { 842 &reiserfs_xattr_user_handler, 843 &reiserfs_xattr_trusted_handler, 844 #ifdef CONFIG_REISERFS_FS_SECURITY 845 &reiserfs_xattr_security_handler, 846 #endif 847 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 848 &reiserfs_posix_acl_access_handler, 849 &reiserfs_posix_acl_default_handler, 850 #endif 851 NULL 852 }; 853 854 /* 855 * In order to implement different sets of xattr operations for each xattr 856 * prefix with the generic xattr API, a filesystem should create a 857 * null-terminated array of struct xattr_handler (one for each prefix) and 858 * hang a pointer to it off of the s_xattr field of the superblock. 859 * 860 * The generic_fooxattr() functions will use this list to dispatch xattr 861 * operations to the correct xattr_handler. 862 */ 863 #define for_each_xattr_handler(handlers, handler) \ 864 for ((handler) = *(handlers)++; \ 865 (handler) != NULL; \ 866 (handler) = *(handlers)++) 867 868 /* This is the implementation for the xattr plugin infrastructure */ 869 static inline struct xattr_handler * 870 find_xattr_handler_prefix(struct xattr_handler **handlers, 871 const char *name) 872 { 873 struct xattr_handler *xah; 874 875 if (!handlers) 876 return NULL; 877 878 for_each_xattr_handler(handlers, xah) { 879 if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0) 880 break; 881 } 882 883 return xah; 884 } 885 886 887 /* 888 * Inode operation getxattr() 889 */ 890 ssize_t 891 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 892 size_t size) 893 { 894 struct inode *inode = dentry->d_inode; 895 struct xattr_handler *handler; 896 897 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 898 899 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 900 return -EOPNOTSUPP; 901 902 return handler->get(inode, name, buffer, size); 903 } 904 905 /* 906 * Inode operation setxattr() 907 * 908 * dentry->d_inode->i_mutex down 909 */ 910 int 911 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 912 size_t size, int flags) 913 { 914 struct inode *inode = dentry->d_inode; 915 struct xattr_handler *handler; 916 917 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 918 919 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 920 return -EOPNOTSUPP; 921 922 return handler->set(inode, name, value, size, flags); 923 } 924 925 /* 926 * Inode operation removexattr() 927 * 928 * dentry->d_inode->i_mutex down 929 */ 930 int reiserfs_removexattr(struct dentry *dentry, const char *name) 931 { 932 struct inode *inode = dentry->d_inode; 933 struct xattr_handler *handler; 934 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 935 936 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 937 return -EOPNOTSUPP; 938 939 return handler->set(inode, name, NULL, 0, XATTR_REPLACE); 940 } 941 942 struct listxattr_buf { 943 size_t size; 944 size_t pos; 945 char *buf; 946 struct inode *inode; 947 }; 948 949 static int listxattr_filler(void *buf, const char *name, int namelen, 950 loff_t offset, u64 ino, unsigned int d_type) 951 { 952 struct listxattr_buf *b = (struct listxattr_buf *)buf; 953 size_t size; 954 if (name[0] != '.' || 955 (namelen != 1 && (name[1] != '.' || namelen != 2))) { 956 struct xattr_handler *handler; 957 handler = find_xattr_handler_prefix(b->inode->i_sb->s_xattr, 958 name); 959 if (!handler) /* Unsupported xattr name */ 960 return 0; 961 if (b->buf) { 962 size = handler->list(b->inode, b->buf + b->pos, 963 b->size, name, namelen); 964 if (size > b->size) 965 return -ERANGE; 966 } else { 967 size = handler->list(b->inode, NULL, 0, name, namelen); 968 } 969 970 b->pos += size; 971 } 972 return 0; 973 } 974 975 /* 976 * Inode operation listxattr() 977 * 978 * We totally ignore the generic listxattr here because it would be stupid 979 * not to. Since the xattrs are organized in a directory, we can just 980 * readdir to find them. 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 listxattr_buf buf = { 987 .inode = dentry->d_inode, 988 .buf = buffer, 989 .size = buffer ? size : 0, 990 }; 991 992 if (!dentry->d_inode) 993 return -EINVAL; 994 995 if (!reiserfs_xattrs(dentry->d_sb) || 996 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 997 return -EOPNOTSUPP; 998 999 dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); 1000 if (IS_ERR(dir)) { 1001 err = PTR_ERR(dir); 1002 if (err == -ENODATA) 1003 err = 0; /* Not an error if there aren't any xattrs */ 1004 goto out; 1005 } 1006 1007 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 1008 err = xattr_readdir(dir->d_inode, listxattr_filler, &buf); 1009 mutex_unlock(&dir->d_inode->i_mutex); 1010 1011 if (!err) 1012 err = buf.pos; 1013 1014 dput(dir); 1015 out: 1016 return err; 1017 } 1018 1019 static int reiserfs_check_acl(struct inode *inode, int mask) 1020 { 1021 struct posix_acl *acl; 1022 int error = -EAGAIN; /* do regular unix permission checks by default */ 1023 1024 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 1025 1026 if (acl) { 1027 if (!IS_ERR(acl)) { 1028 error = posix_acl_permission(inode, acl, mask); 1029 posix_acl_release(acl); 1030 } else if (PTR_ERR(acl) != -ENODATA) 1031 error = PTR_ERR(acl); 1032 } 1033 1034 return error; 1035 } 1036 1037 int reiserfs_permission(struct inode *inode, int mask) 1038 { 1039 /* 1040 * We don't do permission checks on the internal objects. 1041 * Permissions are determined by the "owning" object. 1042 */ 1043 if (IS_PRIVATE(inode)) 1044 return 0; 1045 /* 1046 * Stat data v1 doesn't support ACLs. 1047 */ 1048 if (get_inode_sd_version(inode) == STAT_DATA_V1) 1049 return generic_permission(inode, mask, NULL); 1050 else 1051 return generic_permission(inode, mask, reiserfs_check_acl); 1052 } 1053 1054 static int create_privroot(struct dentry *dentry) 1055 { 1056 int err; 1057 struct inode *inode = dentry->d_parent->d_inode; 1058 mutex_lock_nested(&inode->i_mutex, I_MUTEX_XATTR); 1059 err = xattr_mkdir(inode, dentry, 0700); 1060 mutex_unlock(&inode->i_mutex); 1061 if (err) { 1062 dput(dentry); 1063 dentry = NULL; 1064 } 1065 1066 if (dentry && dentry->d_inode) 1067 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 1068 "storage.\n", PRIVROOT_NAME); 1069 1070 return err; 1071 } 1072 1073 static int xattr_mount_check(struct super_block *s) 1074 { 1075 /* We need generation numbers to ensure that the oid mapping is correct 1076 * v3.5 filesystems don't have them. */ 1077 if (old_format_only(s)) { 1078 if (reiserfs_xattrs_optional(s)) { 1079 /* Old format filesystem, but optional xattrs have 1080 * been enabled. Error out. */ 1081 reiserfs_warning(s, "jdm-2005", 1082 "xattrs/ACLs not supported " 1083 "on pre-v3.6 format filesystems. " 1084 "Failing mount."); 1085 return -EOPNOTSUPP; 1086 } 1087 } 1088 1089 return 0; 1090 } 1091 1092 #else 1093 int __init reiserfs_xattr_register_handlers(void) { return 0; } 1094 void reiserfs_xattr_unregister_handlers(void) {} 1095 #endif 1096 1097 /* This will catch lookups from the fs root to .reiserfs_priv */ 1098 static int 1099 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 1100 { 1101 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 1102 if (name->len == priv_root->d_name.len && 1103 name->hash == priv_root->d_name.hash && 1104 !memcmp(name->name, priv_root->d_name.name, name->len)) { 1105 return -ENOENT; 1106 } else if (q1->len == name->len && 1107 !memcmp(q1->name, name->name, name->len)) 1108 return 0; 1109 return 1; 1110 } 1111 1112 static struct dentry_operations xattr_lookup_poison_ops = { 1113 .d_compare = xattr_lookup_poison, 1114 }; 1115 1116 /* We need to take a copy of the mount flags since things like 1117 * MS_RDONLY don't get set until *after* we're called. 1118 * mount_flags != mount_options */ 1119 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1120 { 1121 int err = 0; 1122 1123 #ifdef CONFIG_REISERFS_FS_XATTR 1124 err = xattr_mount_check(s); 1125 if (err) 1126 goto error; 1127 #endif 1128 1129 /* If we don't have the privroot located yet - go find it */ 1130 if (!REISERFS_SB(s)->priv_root) { 1131 struct dentry *dentry; 1132 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 1133 strlen(PRIVROOT_NAME)); 1134 if (!IS_ERR(dentry)) { 1135 #ifdef CONFIG_REISERFS_FS_XATTR 1136 if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) 1137 err = create_privroot(dentry); 1138 #endif 1139 if (!dentry->d_inode) { 1140 dput(dentry); 1141 dentry = NULL; 1142 } 1143 } else 1144 err = PTR_ERR(dentry); 1145 1146 if (!err && dentry) { 1147 s->s_root->d_op = &xattr_lookup_poison_ops; 1148 dentry->d_inode->i_flags |= S_PRIVATE; 1149 REISERFS_SB(s)->priv_root = dentry; 1150 #ifdef CONFIG_REISERFS_FS_XATTR 1151 /* xattrs are unavailable */ 1152 } else if (!(mount_flags & MS_RDONLY)) { 1153 /* If we're read-only it just means that the dir 1154 * hasn't been created. Not an error -- just no 1155 * xattrs on the fs. We'll check again if we 1156 * go read-write */ 1157 reiserfs_warning(s, "jdm-20006", 1158 "xattrs/ACLs enabled and couldn't " 1159 "find/create .reiserfs_priv. " 1160 "Failing mount."); 1161 err = -EOPNOTSUPP; 1162 #endif 1163 } 1164 } 1165 1166 #ifdef CONFIG_REISERFS_FS_XATTR 1167 if (!err) 1168 s->s_xattr = reiserfs_xattr_handlers; 1169 1170 error: 1171 if (err) { 1172 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1173 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1174 } 1175 #endif 1176 1177 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1178 s->s_flags = s->s_flags & ~MS_POSIXACL; 1179 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 1180 if (reiserfs_posixacl(s)) 1181 s->s_flags |= MS_POSIXACL; 1182 #endif 1183 1184 return err; 1185 } 1186