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 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char *); 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 /* expects xadir->d_inode->i_mutex to be locked */ 343 static int 344 __reiserfs_xattr_del(struct dentry *xadir, const char *name, int namelen) 345 { 346 struct dentry *dentry; 347 struct inode *dir = xadir->d_inode; 348 int err = 0; 349 struct reiserfs_xattr_handler *xah; 350 351 dentry = lookup_one_len(name, xadir, namelen); 352 if (IS_ERR(dentry)) { 353 err = PTR_ERR(dentry); 354 goto out; 355 } else if (!dentry->d_inode) { 356 err = -ENODATA; 357 goto out_file; 358 } 359 360 /* Skip directories.. */ 361 if (S_ISDIR(dentry->d_inode->i_mode)) 362 goto out_file; 363 364 if (!IS_PRIVATE(dentry->d_inode)) { 365 reiserfs_error(dir->i_sb, "jdm-20003", 366 "OID %08x [%.*s/%.*s] doesn't have " 367 "priv flag set [parent is %sset].", 368 le32_to_cpu(INODE_PKEY(dentry->d_inode)-> 369 k_objectid), xadir->d_name.len, 370 xadir->d_name.name, namelen, name, 371 IS_PRIVATE(xadir->d_inode) ? "" : 372 "not "); 373 dput(dentry); 374 return -EIO; 375 } 376 377 /* Deletion pre-operation */ 378 xah = find_xattr_handler_prefix(name); 379 if (xah && xah->del) { 380 err = xah->del(dentry->d_inode, name); 381 if (err) 382 goto out; 383 } 384 385 err = xattr_unlink(dir, dentry); 386 387 out_file: 388 dput(dentry); 389 390 out: 391 return err; 392 } 393 394 /* The following are side effects of other operations that aren't explicitly 395 * modifying extended attributes. This includes operations such as permissions 396 * or ownership changes, object deletions, etc. */ 397 398 static int 399 reiserfs_delete_xattrs_filler(void *buf, const char *name, int namelen, 400 loff_t offset, u64 ino, unsigned int d_type) 401 { 402 struct dentry *xadir = (struct dentry *)buf; 403 404 return __reiserfs_xattr_del(xadir, name, namelen); 405 406 } 407 408 /* This is called w/ inode->i_mutex downed */ 409 int reiserfs_delete_xattrs(struct inode *inode) 410 { 411 int err = -ENODATA; 412 struct dentry *dir, *root; 413 struct reiserfs_transaction_handle th; 414 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 415 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); 416 417 /* Skip out, an xattr has no xattrs associated with it */ 418 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 419 return 0; 420 421 dir = open_xa_dir(inode, XATTR_REPLACE); 422 if (IS_ERR(dir)) { 423 err = PTR_ERR(dir); 424 goto out; 425 } else if (!dir->d_inode) { 426 dput(dir); 427 goto out; 428 } 429 430 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 431 err = xattr_readdir(dir->d_inode, reiserfs_delete_xattrs_filler, dir); 432 mutex_unlock(&dir->d_inode->i_mutex); 433 if (err) { 434 dput(dir); 435 goto out; 436 } 437 438 root = dget(dir->d_parent); 439 dput(dir); 440 441 /* We start a transaction here to avoid a ABBA situation 442 * between the xattr root's i_mutex and the journal lock. 443 * Inode creation will inherit an ACL, which requires a 444 * lookup. The lookup locks the xattr root i_mutex with a 445 * transaction open. Inode deletion takes teh xattr root 446 * i_mutex to delete the directory and then starts a 447 * transaction inside it. Boom. This doesn't incur much 448 * additional overhead since the reiserfs_rmdir transaction 449 * will just nest inside the outer transaction. */ 450 err = journal_begin(&th, inode->i_sb, blocks); 451 if (!err) { 452 int jerror; 453 mutex_lock_nested(&root->d_inode->i_mutex, I_MUTEX_XATTR); 454 err = xattr_rmdir(root->d_inode, dir); 455 jerror = journal_end(&th, inode->i_sb, blocks); 456 mutex_unlock(&root->d_inode->i_mutex); 457 err = jerror ?: err; 458 } 459 460 dput(root); 461 out: 462 if (err) 463 reiserfs_warning(inode->i_sb, "jdm-20004", 464 "Couldn't remove all xattrs (%d)\n", err); 465 return err; 466 } 467 468 struct reiserfs_chown_buf { 469 struct inode *inode; 470 struct dentry *xadir; 471 struct iattr *attrs; 472 }; 473 474 /* XXX: If there is a better way to do this, I'd love to hear about it */ 475 static int 476 reiserfs_chown_xattrs_filler(void *buf, const char *name, int namelen, 477 loff_t offset, u64 ino, unsigned int d_type) 478 { 479 struct reiserfs_chown_buf *chown_buf = (struct reiserfs_chown_buf *)buf; 480 struct dentry *xafile, *xadir = chown_buf->xadir; 481 struct iattr *attrs = chown_buf->attrs; 482 int err = 0; 483 484 xafile = lookup_one_len(name, xadir, namelen); 485 if (IS_ERR(xafile)) 486 return PTR_ERR(xafile); 487 else if (!xafile->d_inode) { 488 dput(xafile); 489 return -ENODATA; 490 } 491 492 if (!S_ISDIR(xafile->d_inode->i_mode)) { 493 mutex_lock_nested(&xafile->d_inode->i_mutex, I_MUTEX_CHILD); 494 err = reiserfs_setattr(xafile, attrs); 495 mutex_unlock(&xafile->d_inode->i_mutex); 496 } 497 dput(xafile); 498 499 return err; 500 } 501 502 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 503 { 504 struct dentry *dir; 505 int err = 0; 506 struct reiserfs_chown_buf buf; 507 unsigned int ia_valid = attrs->ia_valid; 508 509 /* Skip out, an xattr has no xattrs associated with it */ 510 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 511 return 0; 512 513 dir = open_xa_dir(inode, XATTR_REPLACE); 514 if (IS_ERR(dir)) { 515 if (PTR_ERR(dir) != -ENODATA) 516 err = PTR_ERR(dir); 517 goto out; 518 } else if (!dir->d_inode) 519 goto out_dir; 520 521 attrs->ia_valid &= (ATTR_UID | ATTR_GID | ATTR_CTIME); 522 buf.xadir = dir; 523 buf.attrs = attrs; 524 buf.inode = inode; 525 526 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 527 err = xattr_readdir(dir->d_inode, reiserfs_chown_xattrs_filler, &buf); 528 529 if (!err) 530 err = reiserfs_setattr(dir, attrs); 531 mutex_unlock(&dir->d_inode->i_mutex); 532 533 attrs->ia_valid = ia_valid; 534 out_dir: 535 dput(dir); 536 out: 537 if (err) 538 reiserfs_warning(inode->i_sb, "jdm-20007", 539 "Couldn't chown all xattrs (%d)\n", err); 540 return err; 541 } 542 543 #ifdef CONFIG_REISERFS_FS_XATTR 544 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char 545 *prefix); 546 547 /* Returns a dentry corresponding to a specific extended attribute file 548 * for the inode. If flags allow, the file is created. Otherwise, a 549 * valid or negative dentry, or an error is returned. */ 550 static struct dentry *get_xa_file_dentry(const struct inode *inode, 551 const char *name, int flags) 552 { 553 struct dentry *xadir, *xafile; 554 int err = 0; 555 556 xadir = open_xa_dir(inode, flags); 557 if (IS_ERR(xadir)) 558 return ERR_CAST(xadir); 559 560 xafile = lookup_one_len(name, xadir, strlen(name)); 561 if (IS_ERR(xafile)) { 562 err = PTR_ERR(xafile); 563 goto out; 564 } 565 566 if (xafile->d_inode && (flags & XATTR_CREATE)) 567 err = -EEXIST; 568 569 if (!xafile->d_inode) { 570 err = -ENODATA; 571 if (xattr_may_create(flags)) { 572 mutex_lock_nested(&xadir->d_inode->i_mutex, 573 I_MUTEX_XATTR); 574 err = xattr_create(xadir->d_inode, xafile, 575 0700|S_IFREG); 576 mutex_unlock(&xadir->d_inode->i_mutex); 577 } 578 } 579 580 if (err) 581 dput(xafile); 582 out: 583 dput(xadir); 584 if (err) 585 return ERR_PTR(err); 586 return xafile; 587 } 588 589 /* Internal operations on file data */ 590 static inline void reiserfs_put_page(struct page *page) 591 { 592 kunmap(page); 593 page_cache_release(page); 594 } 595 596 static struct page *reiserfs_get_page(struct inode *dir, size_t n) 597 { 598 struct address_space *mapping = dir->i_mapping; 599 struct page *page; 600 /* We can deadlock if we try to free dentries, 601 and an unlink/rmdir has just occured - GFP_NOFS avoids this */ 602 mapping_set_gfp_mask(mapping, GFP_NOFS); 603 page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); 604 if (!IS_ERR(page)) { 605 kmap(page); 606 if (PageError(page)) 607 goto fail; 608 } 609 return page; 610 611 fail: 612 reiserfs_put_page(page); 613 return ERR_PTR(-EIO); 614 } 615 616 static inline __u32 xattr_hash(const char *msg, int len) 617 { 618 return csum_partial(msg, len, 0); 619 } 620 621 int reiserfs_commit_write(struct file *f, struct page *page, 622 unsigned from, unsigned to); 623 int reiserfs_prepare_write(struct file *f, struct page *page, 624 unsigned from, unsigned to); 625 626 627 /* Generic extended attribute operations that can be used by xa plugins */ 628 629 /* 630 * inode->i_mutex: down 631 */ 632 int 633 reiserfs_xattr_set(struct inode *inode, const char *name, const void *buffer, 634 size_t buffer_size, int flags) 635 { 636 int err = 0; 637 struct dentry *dentry; 638 struct page *page; 639 char *data; 640 size_t file_pos = 0; 641 size_t buffer_pos = 0; 642 struct iattr newattrs; 643 __u32 xahash = 0; 644 645 if (get_inode_sd_version(inode) == STAT_DATA_V1) 646 return -EOPNOTSUPP; 647 648 if (!buffer) 649 return reiserfs_xattr_del(inode, name); 650 651 dentry = get_xa_file_dentry(inode, name, flags); 652 if (IS_ERR(dentry)) { 653 err = PTR_ERR(dentry); 654 goto out; 655 } 656 657 down_write(&REISERFS_I(inode)->i_xattr_sem); 658 659 xahash = xattr_hash(buffer, buffer_size); 660 661 /* Resize it so we're ok to write there */ 662 newattrs.ia_size = buffer_size; 663 newattrs.ia_ctime = current_fs_time(inode->i_sb); 664 newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; 665 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 666 down_write(&dentry->d_inode->i_alloc_sem); 667 err = reiserfs_setattr(dentry, &newattrs); 668 up_write(&dentry->d_inode->i_alloc_sem); 669 mutex_unlock(&dentry->d_inode->i_mutex); 670 if (err) 671 goto out_filp; 672 673 while (buffer_pos < buffer_size || buffer_pos == 0) { 674 size_t chunk; 675 size_t skip = 0; 676 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 677 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 678 chunk = PAGE_CACHE_SIZE; 679 else 680 chunk = buffer_size - buffer_pos; 681 682 page = reiserfs_get_page(dentry->d_inode, file_pos); 683 if (IS_ERR(page)) { 684 err = PTR_ERR(page); 685 goto out_filp; 686 } 687 688 lock_page(page); 689 data = page_address(page); 690 691 if (file_pos == 0) { 692 struct reiserfs_xattr_header *rxh; 693 skip = file_pos = sizeof(struct reiserfs_xattr_header); 694 if (chunk + skip > PAGE_CACHE_SIZE) 695 chunk = PAGE_CACHE_SIZE - skip; 696 rxh = (struct reiserfs_xattr_header *)data; 697 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 698 rxh->h_hash = cpu_to_le32(xahash); 699 } 700 701 err = reiserfs_prepare_write(NULL, page, page_offset, 702 page_offset + chunk + skip); 703 if (!err) { 704 if (buffer) 705 memcpy(data + skip, buffer + buffer_pos, chunk); 706 err = reiserfs_commit_write(NULL, page, page_offset, 707 page_offset + chunk + 708 skip); 709 } 710 unlock_page(page); 711 reiserfs_put_page(page); 712 buffer_pos += chunk; 713 file_pos += chunk; 714 skip = 0; 715 if (err || buffer_size == 0 || !buffer) 716 break; 717 } 718 719 /* We can't mark the inode dirty if it's not hashed. This is the case 720 * when we're inheriting the default ACL. If we dirty it, the inode 721 * gets marked dirty, but won't (ever) make it onto the dirty list until 722 * it's synced explicitly to clear I_DIRTY. This is bad. */ 723 if (!hlist_unhashed(&inode->i_hash)) { 724 inode->i_ctime = CURRENT_TIME_SEC; 725 mark_inode_dirty(inode); 726 } 727 728 out_filp: 729 up_write(&REISERFS_I(inode)->i_xattr_sem); 730 dput(dentry); 731 732 out: 733 return err; 734 } 735 736 /* 737 * inode->i_mutex: down 738 */ 739 int 740 reiserfs_xattr_get(const 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 = get_xa_file_dentry(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 int reiserfs_xattr_del(struct inode *inode, const char *name) 841 { 842 struct dentry *dir; 843 int err; 844 845 dir = open_xa_dir(inode, XATTR_REPLACE); 846 if (IS_ERR(dir)) { 847 err = PTR_ERR(dir); 848 goto out; 849 } 850 851 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 852 err = __reiserfs_xattr_del(dir, name, strlen(name)); 853 mutex_unlock(&dir->d_inode->i_mutex); 854 dput(dir); 855 856 if (!err) { 857 inode->i_ctime = CURRENT_TIME_SEC; 858 mark_inode_dirty(inode); 859 } 860 861 out: 862 return err; 863 } 864 865 /* Actual operations that are exported to VFS-land */ 866 /* 867 * Inode operation getxattr() 868 */ 869 ssize_t 870 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 871 size_t size) 872 { 873 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 874 int err; 875 876 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 877 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 878 return -EOPNOTSUPP; 879 880 err = xah->get(dentry->d_inode, name, buffer, size); 881 return err; 882 } 883 884 /* 885 * Inode operation setxattr() 886 * 887 * dentry->d_inode->i_mutex down 888 */ 889 int 890 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 891 size_t size, int flags) 892 { 893 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 894 int err; 895 896 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 897 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 898 return -EOPNOTSUPP; 899 900 err = xah->set(dentry->d_inode, name, value, size, flags); 901 return err; 902 } 903 904 /* 905 * Inode operation removexattr() 906 * 907 * dentry->d_inode->i_mutex down 908 */ 909 int reiserfs_removexattr(struct dentry *dentry, const char *name) 910 { 911 int err; 912 struct reiserfs_xattr_handler *xah = find_xattr_handler_prefix(name); 913 914 if (!xah || !reiserfs_xattrs(dentry->d_sb) || 915 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 916 return -EOPNOTSUPP; 917 918 err = reiserfs_xattr_del(dentry->d_inode, name); 919 920 dentry->d_inode->i_ctime = CURRENT_TIME_SEC; 921 mark_inode_dirty(dentry->d_inode); 922 923 return err; 924 } 925 926 /* This is what filldir will use: 927 * r_pos will always contain the amount of space required for the entire 928 * list. If r_pos becomes larger than r_size, we need more space and we 929 * return an error indicating this. If r_pos is less than r_size, then we've 930 * filled the buffer successfully and we return success */ 931 struct reiserfs_listxattr_buf { 932 int r_pos; 933 int r_size; 934 char *r_buf; 935 struct inode *r_inode; 936 }; 937 938 static int 939 reiserfs_listxattr_filler(void *buf, const char *name, int namelen, 940 loff_t offset, u64 ino, unsigned int d_type) 941 { 942 struct reiserfs_listxattr_buf *b = (struct reiserfs_listxattr_buf *)buf; 943 int len = 0; 944 if (name[0] != '.' 945 || (namelen != 1 && (name[1] != '.' || namelen != 2))) { 946 struct reiserfs_xattr_handler *xah = 947 find_xattr_handler_prefix(name); 948 if (!xah) 949 return 0; /* Unsupported xattr name, skip it */ 950 951 /* We call ->list() twice because the operation isn't required to just 952 * return the name back - we want to make sure we have enough space */ 953 len += xah->list(b->r_inode, name, namelen, NULL); 954 955 if (len) { 956 if (b->r_pos + len + 1 <= b->r_size) { 957 char *p = b->r_buf + b->r_pos; 958 p += xah->list(b->r_inode, name, namelen, p); 959 *p++ = '\0'; 960 } 961 b->r_pos += len + 1; 962 } 963 } 964 965 return 0; 966 } 967 968 /* 969 * Inode operation listxattr() 970 */ 971 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 972 { 973 struct dentry *dir; 974 int err = 0; 975 struct reiserfs_listxattr_buf buf; 976 977 if (!dentry->d_inode) 978 return -EINVAL; 979 980 if (!reiserfs_xattrs(dentry->d_sb) || 981 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 982 return -EOPNOTSUPP; 983 984 dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); 985 if (IS_ERR(dir)) { 986 err = PTR_ERR(dir); 987 if (err == -ENODATA) 988 err = 0; /* Not an error if there aren't any xattrs */ 989 goto out; 990 } 991 992 buf.r_buf = buffer; 993 buf.r_size = buffer ? size : 0; 994 buf.r_pos = 0; 995 buf.r_inode = dentry->d_inode; 996 997 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 998 err = xattr_readdir(dir->d_inode, reiserfs_listxattr_filler, &buf); 999 mutex_unlock(&dir->d_inode->i_mutex); 1000 1001 if (!err) { 1002 if (buf.r_pos > buf.r_size && buffer != NULL) 1003 err = -ERANGE; 1004 else 1005 err = buf.r_pos; 1006 } 1007 1008 dput(dir); 1009 out: 1010 return err; 1011 } 1012 1013 /* This is the implementation for the xattr plugin infrastructure */ 1014 static LIST_HEAD(xattr_handlers); 1015 static DEFINE_RWLOCK(handler_lock); 1016 1017 static struct reiserfs_xattr_handler *find_xattr_handler_prefix(const char 1018 *prefix) 1019 { 1020 struct reiserfs_xattr_handler *xah = NULL; 1021 struct list_head *p; 1022 1023 read_lock(&handler_lock); 1024 list_for_each(p, &xattr_handlers) { 1025 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1026 if (strncmp(xah->prefix, prefix, strlen(xah->prefix)) == 0) 1027 break; 1028 xah = NULL; 1029 } 1030 1031 read_unlock(&handler_lock); 1032 return xah; 1033 } 1034 1035 static void __unregister_handlers(void) 1036 { 1037 struct reiserfs_xattr_handler *xah; 1038 struct list_head *p, *tmp; 1039 1040 list_for_each_safe(p, tmp, &xattr_handlers) { 1041 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1042 if (xah->exit) 1043 xah->exit(); 1044 1045 list_del_init(p); 1046 } 1047 INIT_LIST_HEAD(&xattr_handlers); 1048 } 1049 1050 int __init reiserfs_xattr_register_handlers(void) 1051 { 1052 int err = 0; 1053 struct reiserfs_xattr_handler *xah; 1054 struct list_head *p; 1055 1056 write_lock(&handler_lock); 1057 1058 /* If we're already initialized, nothing to do */ 1059 if (!list_empty(&xattr_handlers)) { 1060 write_unlock(&handler_lock); 1061 return 0; 1062 } 1063 1064 /* Add the handlers */ 1065 list_add_tail(&user_handler.handlers, &xattr_handlers); 1066 list_add_tail(&trusted_handler.handlers, &xattr_handlers); 1067 #ifdef CONFIG_REISERFS_FS_SECURITY 1068 list_add_tail(&security_handler.handlers, &xattr_handlers); 1069 #endif 1070 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 1071 list_add_tail(&posix_acl_access_handler.handlers, &xattr_handlers); 1072 list_add_tail(&posix_acl_default_handler.handlers, &xattr_handlers); 1073 #endif 1074 1075 /* Run initializers, if available */ 1076 list_for_each(p, &xattr_handlers) { 1077 xah = list_entry(p, struct reiserfs_xattr_handler, handlers); 1078 if (xah->init) { 1079 err = xah->init(); 1080 if (err) { 1081 list_del_init(p); 1082 break; 1083 } 1084 } 1085 } 1086 1087 /* Clean up other handlers, if any failed */ 1088 if (err) 1089 __unregister_handlers(); 1090 1091 write_unlock(&handler_lock); 1092 return err; 1093 } 1094 1095 void reiserfs_xattr_unregister_handlers(void) 1096 { 1097 write_lock(&handler_lock); 1098 __unregister_handlers(); 1099 write_unlock(&handler_lock); 1100 } 1101 1102 static int reiserfs_check_acl(struct inode *inode, int mask) 1103 { 1104 struct posix_acl *acl; 1105 int error = -EAGAIN; /* do regular unix permission checks by default */ 1106 1107 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 1108 1109 if (acl) { 1110 if (!IS_ERR(acl)) { 1111 error = posix_acl_permission(inode, acl, mask); 1112 posix_acl_release(acl); 1113 } else if (PTR_ERR(acl) != -ENODATA) 1114 error = PTR_ERR(acl); 1115 } 1116 1117 return error; 1118 } 1119 1120 int reiserfs_permission(struct inode *inode, int mask) 1121 { 1122 /* 1123 * We don't do permission checks on the internal objects. 1124 * Permissions are determined by the "owning" object. 1125 */ 1126 if (IS_PRIVATE(inode)) 1127 return 0; 1128 /* 1129 * Stat data v1 doesn't support ACLs. 1130 */ 1131 if (get_inode_sd_version(inode) == STAT_DATA_V1) 1132 return generic_permission(inode, mask, NULL); 1133 else 1134 return generic_permission(inode, mask, reiserfs_check_acl); 1135 } 1136 1137 static int create_privroot(struct dentry *dentry) 1138 { 1139 int err; 1140 struct inode *inode = dentry->d_parent->d_inode; 1141 mutex_lock_nested(&inode->i_mutex, I_MUTEX_XATTR); 1142 err = xattr_mkdir(inode, dentry, 0700); 1143 mutex_unlock(&inode->i_mutex); 1144 if (err) { 1145 dput(dentry); 1146 dentry = NULL; 1147 } 1148 1149 if (dentry && dentry->d_inode) 1150 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 1151 "storage.\n", PRIVROOT_NAME); 1152 1153 return err; 1154 } 1155 1156 static int xattr_mount_check(struct super_block *s) 1157 { 1158 /* We need generation numbers to ensure that the oid mapping is correct 1159 * v3.5 filesystems don't have them. */ 1160 if (!old_format_only(s)) { 1161 set_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1162 } else if (reiserfs_xattrs_optional(s)) { 1163 /* Old format filesystem, but optional xattrs have been enabled 1164 * at mount time. Error out. */ 1165 reiserfs_warning(s, "jdm-20005", 1166 "xattrs/ACLs not supported on pre v3.6 " 1167 "format filesystem. Failing mount."); 1168 return -EOPNOTSUPP; 1169 } else { 1170 /* Old format filesystem, but no optional xattrs have 1171 * been enabled. This means we silently disable xattrs 1172 * on the filesystem. */ 1173 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1174 } 1175 1176 return 0; 1177 } 1178 1179 #else 1180 int __init reiserfs_xattr_register_handlers(void) { return 0; } 1181 void reiserfs_xattr_unregister_handlers(void) {} 1182 #endif 1183 1184 /* This will catch lookups from the fs root to .reiserfs_priv */ 1185 static int 1186 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 1187 { 1188 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 1189 if (name->len == priv_root->d_name.len && 1190 name->hash == priv_root->d_name.hash && 1191 !memcmp(name->name, priv_root->d_name.name, name->len)) { 1192 return -ENOENT; 1193 } else if (q1->len == name->len && 1194 !memcmp(q1->name, name->name, name->len)) 1195 return 0; 1196 return 1; 1197 } 1198 1199 static struct dentry_operations xattr_lookup_poison_ops = { 1200 .d_compare = xattr_lookup_poison, 1201 }; 1202 1203 /* We need to take a copy of the mount flags since things like 1204 * MS_RDONLY don't get set until *after* we're called. 1205 * mount_flags != mount_options */ 1206 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1207 { 1208 int err = 0; 1209 1210 #ifdef CONFIG_REISERFS_FS_XATTR 1211 err = xattr_mount_check(s); 1212 if (err) 1213 goto error; 1214 #endif 1215 1216 /* If we don't have the privroot located yet - go find it */ 1217 if (!REISERFS_SB(s)->priv_root) { 1218 struct dentry *dentry; 1219 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 1220 strlen(PRIVROOT_NAME)); 1221 if (!IS_ERR(dentry)) { 1222 #ifdef CONFIG_REISERFS_FS_XATTR 1223 if (!(mount_flags & MS_RDONLY) && !dentry->d_inode) 1224 err = create_privroot(dentry); 1225 #endif 1226 if (!dentry->d_inode) { 1227 dput(dentry); 1228 dentry = NULL; 1229 } 1230 } else 1231 err = PTR_ERR(dentry); 1232 1233 if (!err && dentry) { 1234 s->s_root->d_op = &xattr_lookup_poison_ops; 1235 dentry->d_inode->i_flags |= S_PRIVATE; 1236 REISERFS_SB(s)->priv_root = dentry; 1237 #ifdef CONFIG_REISERFS_FS_XATTR 1238 /* xattrs are unavailable */ 1239 } else if (!(mount_flags & MS_RDONLY)) { 1240 /* If we're read-only it just means that the dir 1241 * hasn't been created. Not an error -- just no 1242 * xattrs on the fs. We'll check again if we 1243 * go read-write */ 1244 reiserfs_warning(s, "jdm-20006", 1245 "xattrs/ACLs enabled and couldn't " 1246 "find/create .reiserfs_priv. " 1247 "Failing mount."); 1248 err = -EOPNOTSUPP; 1249 #endif 1250 } 1251 } 1252 1253 #ifdef CONFIG_REISERFS_FS_XATTR 1254 error: 1255 if (err) { 1256 clear_bit(REISERFS_XATTRS, &(REISERFS_SB(s)->s_mount_opt)); 1257 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1258 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1259 } 1260 #endif 1261 1262 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1263 s->s_flags = s->s_flags & ~MS_POSIXACL; 1264 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 1265 if (reiserfs_posixacl(s)) 1266 s->s_flags |= MS_POSIXACL; 1267 #endif 1268 1269 return err; 1270 } 1271