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 "reiserfs.h" 37 #include <linux/capability.h> 38 #include <linux/dcache.h> 39 #include <linux/namei.h> 40 #include <linux/errno.h> 41 #include <linux/gfp.h> 42 #include <linux/fs.h> 43 #include <linux/file.h> 44 #include <linux/pagemap.h> 45 #include <linux/xattr.h> 46 #include "xattr.h" 47 #include "acl.h" 48 #include <asm/uaccess.h> 49 #include <net/checksum.h> 50 #include <linux/stat.h> 51 #include <linux/quotaops.h> 52 #include <linux/security.h> 53 54 #define PRIVROOT_NAME ".reiserfs_priv" 55 #define XAROOT_NAME "xattrs" 56 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 #ifdef CONFIG_REISERFS_FS_XATTR 62 static int xattr_create(struct inode *dir, struct dentry *dentry, int mode) 63 { 64 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 65 return dir->i_op->create(dir, dentry, mode, true); 66 } 67 #endif 68 69 static int xattr_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 70 { 71 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 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 84 reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex, 85 I_MUTEX_CHILD, dir->i_sb); 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 99 reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex, 100 I_MUTEX_CHILD, dir->i_sb); 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); 107 108 return error; 109 } 110 111 #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE) 112 113 static struct dentry *open_xa_root(struct super_block *sb, int flags) 114 { 115 struct dentry *privroot = REISERFS_SB(sb)->priv_root; 116 struct dentry *xaroot; 117 if (!privroot->d_inode) 118 return ERR_PTR(-ENODATA); 119 120 mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR); 121 122 xaroot = dget(REISERFS_SB(sb)->xattr_root); 123 if (!xaroot) 124 xaroot = ERR_PTR(-ENODATA); 125 else if (!xaroot->d_inode) { 126 int err = -ENODATA; 127 if (xattr_may_create(flags)) 128 err = xattr_mkdir(privroot->d_inode, xaroot, 0700); 129 if (err) { 130 dput(xaroot); 131 xaroot = ERR_PTR(err); 132 } 133 } 134 135 mutex_unlock(&privroot->d_inode->i_mutex); 136 return xaroot; 137 } 138 139 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 140 { 141 struct dentry *xaroot, *xadir; 142 char namebuf[17]; 143 144 xaroot = open_xa_root(inode->i_sb, flags); 145 if (IS_ERR(xaroot)) 146 return xaroot; 147 148 snprintf(namebuf, sizeof(namebuf), "%X.%X", 149 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 150 inode->i_generation); 151 152 mutex_lock_nested(&xaroot->d_inode->i_mutex, I_MUTEX_XATTR); 153 154 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); 155 if (!IS_ERR(xadir) && !xadir->d_inode) { 156 int err = -ENODATA; 157 if (xattr_may_create(flags)) 158 err = xattr_mkdir(xaroot->d_inode, xadir, 0700); 159 if (err) { 160 dput(xadir); 161 xadir = ERR_PTR(err); 162 } 163 } 164 165 mutex_unlock(&xaroot->d_inode->i_mutex); 166 dput(xaroot); 167 return xadir; 168 } 169 170 /* The following are side effects of other operations that aren't explicitly 171 * modifying extended attributes. This includes operations such as permissions 172 * or ownership changes, object deletions, etc. */ 173 struct reiserfs_dentry_buf { 174 struct dentry *xadir; 175 int count; 176 struct dentry *dentries[8]; 177 }; 178 179 static int 180 fill_with_dentries(void *buf, const char *name, int namelen, loff_t offset, 181 u64 ino, unsigned int d_type) 182 { 183 struct reiserfs_dentry_buf *dbuf = buf; 184 struct dentry *dentry; 185 WARN_ON_ONCE(!mutex_is_locked(&dbuf->xadir->d_inode->i_mutex)); 186 187 if (dbuf->count == ARRAY_SIZE(dbuf->dentries)) 188 return -ENOSPC; 189 190 if (name[0] == '.' && (namelen < 2 || 191 (namelen == 2 && name[1] == '.'))) 192 return 0; 193 194 dentry = lookup_one_len(name, dbuf->xadir, namelen); 195 if (IS_ERR(dentry)) { 196 return PTR_ERR(dentry); 197 } else if (!dentry->d_inode) { 198 /* A directory entry exists, but no file? */ 199 reiserfs_error(dentry->d_sb, "xattr-20003", 200 "Corrupted directory: xattr %s listed but " 201 "not found for file %s.\n", 202 dentry->d_name.name, dbuf->xadir->d_name.name); 203 dput(dentry); 204 return -EIO; 205 } 206 207 dbuf->dentries[dbuf->count++] = dentry; 208 return 0; 209 } 210 211 static void 212 cleanup_dentry_buf(struct reiserfs_dentry_buf *buf) 213 { 214 int i; 215 for (i = 0; i < buf->count; i++) 216 if (buf->dentries[i]) 217 dput(buf->dentries[i]); 218 } 219 220 static int reiserfs_for_each_xattr(struct inode *inode, 221 int (*action)(struct dentry *, void *), 222 void *data) 223 { 224 struct dentry *dir; 225 int i, err = 0; 226 loff_t pos = 0; 227 struct reiserfs_dentry_buf buf = { 228 .count = 0, 229 }; 230 231 /* Skip out, an xattr has no xattrs associated with it */ 232 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 233 return 0; 234 235 reiserfs_write_unlock(inode->i_sb); 236 dir = open_xa_dir(inode, XATTR_REPLACE); 237 if (IS_ERR(dir)) { 238 err = PTR_ERR(dir); 239 reiserfs_write_lock(inode->i_sb); 240 goto out; 241 } else if (!dir->d_inode) { 242 err = 0; 243 reiserfs_write_lock(inode->i_sb); 244 goto out_dir; 245 } 246 247 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 248 249 reiserfs_write_lock(inode->i_sb); 250 251 buf.xadir = dir; 252 err = reiserfs_readdir_dentry(dir, &buf, fill_with_dentries, &pos); 253 while ((err == 0 || err == -ENOSPC) && buf.count) { 254 err = 0; 255 256 for (i = 0; i < buf.count && buf.dentries[i]; i++) { 257 int lerr = 0; 258 struct dentry *dentry = buf.dentries[i]; 259 260 if (err == 0 && !S_ISDIR(dentry->d_inode->i_mode)) 261 lerr = action(dentry, data); 262 263 dput(dentry); 264 buf.dentries[i] = NULL; 265 err = lerr ?: err; 266 } 267 buf.count = 0; 268 if (!err) 269 err = reiserfs_readdir_dentry(dir, &buf, 270 fill_with_dentries, &pos); 271 } 272 mutex_unlock(&dir->d_inode->i_mutex); 273 274 /* Clean up after a failed readdir */ 275 cleanup_dentry_buf(&buf); 276 277 if (!err) { 278 /* We start a transaction here to avoid a ABBA situation 279 * between the xattr root's i_mutex and the journal lock. 280 * This doesn't incur much additional overhead since the 281 * new transaction will just nest inside the 282 * outer transaction. */ 283 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 284 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); 285 struct reiserfs_transaction_handle th; 286 err = journal_begin(&th, inode->i_sb, blocks); 287 if (!err) { 288 int jerror; 289 reiserfs_mutex_lock_nested_safe( 290 &dir->d_parent->d_inode->i_mutex, 291 I_MUTEX_XATTR, inode->i_sb); 292 err = action(dir, data); 293 jerror = journal_end(&th, inode->i_sb, blocks); 294 mutex_unlock(&dir->d_parent->d_inode->i_mutex); 295 err = jerror ?: err; 296 } 297 } 298 out_dir: 299 dput(dir); 300 out: 301 /* -ENODATA isn't an error */ 302 if (err == -ENODATA) 303 err = 0; 304 return err; 305 } 306 307 static int delete_one_xattr(struct dentry *dentry, void *data) 308 { 309 struct inode *dir = dentry->d_parent->d_inode; 310 311 /* This is the xattr dir, handle specially. */ 312 if (S_ISDIR(dentry->d_inode->i_mode)) 313 return xattr_rmdir(dir, dentry); 314 315 return xattr_unlink(dir, dentry); 316 } 317 318 static int chown_one_xattr(struct dentry *dentry, void *data) 319 { 320 struct iattr *attrs = data; 321 int ia_valid = attrs->ia_valid; 322 int err; 323 324 /* 325 * We only want the ownership bits. Otherwise, we'll do 326 * things like change a directory to a regular file if 327 * ATTR_MODE is set. 328 */ 329 attrs->ia_valid &= (ATTR_UID|ATTR_GID); 330 err = reiserfs_setattr(dentry, attrs); 331 attrs->ia_valid = ia_valid; 332 333 return err; 334 } 335 336 /* No i_mutex, but the inode is unconnected. */ 337 int reiserfs_delete_xattrs(struct inode *inode) 338 { 339 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL); 340 if (err) 341 reiserfs_warning(inode->i_sb, "jdm-20004", 342 "Couldn't delete all xattrs (%d)\n", err); 343 return err; 344 } 345 346 /* inode->i_mutex: down */ 347 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 348 { 349 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs); 350 if (err) 351 reiserfs_warning(inode->i_sb, "jdm-20007", 352 "Couldn't chown all xattrs (%d)\n", err); 353 return err; 354 } 355 356 #ifdef CONFIG_REISERFS_FS_XATTR 357 /* Returns a dentry corresponding to a specific extended attribute file 358 * for the inode. If flags allow, the file is created. Otherwise, a 359 * valid or negative dentry, or an error is returned. */ 360 static struct dentry *xattr_lookup(struct inode *inode, const char *name, 361 int flags) 362 { 363 struct dentry *xadir, *xafile; 364 int err = 0; 365 366 xadir = open_xa_dir(inode, flags); 367 if (IS_ERR(xadir)) 368 return ERR_CAST(xadir); 369 370 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 371 xafile = lookup_one_len(name, xadir, strlen(name)); 372 if (IS_ERR(xafile)) { 373 err = PTR_ERR(xafile); 374 goto out; 375 } 376 377 if (xafile->d_inode && (flags & XATTR_CREATE)) 378 err = -EEXIST; 379 380 if (!xafile->d_inode) { 381 err = -ENODATA; 382 if (xattr_may_create(flags)) 383 err = xattr_create(xadir->d_inode, xafile, 384 0700|S_IFREG); 385 } 386 387 if (err) 388 dput(xafile); 389 out: 390 mutex_unlock(&xadir->d_inode->i_mutex); 391 dput(xadir); 392 if (err) 393 return ERR_PTR(err); 394 return xafile; 395 } 396 397 /* Internal operations on file data */ 398 static inline void reiserfs_put_page(struct page *page) 399 { 400 kunmap(page); 401 page_cache_release(page); 402 } 403 404 static struct page *reiserfs_get_page(struct inode *dir, size_t n) 405 { 406 struct address_space *mapping = dir->i_mapping; 407 struct page *page; 408 /* We can deadlock if we try to free dentries, 409 and an unlink/rmdir has just occurred - GFP_NOFS avoids this */ 410 mapping_set_gfp_mask(mapping, GFP_NOFS); 411 page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); 412 if (!IS_ERR(page)) { 413 kmap(page); 414 if (PageError(page)) 415 goto fail; 416 } 417 return page; 418 419 fail: 420 reiserfs_put_page(page); 421 return ERR_PTR(-EIO); 422 } 423 424 static inline __u32 xattr_hash(const char *msg, int len) 425 { 426 return csum_partial(msg, len, 0); 427 } 428 429 int reiserfs_commit_write(struct file *f, struct page *page, 430 unsigned from, unsigned to); 431 432 static void update_ctime(struct inode *inode) 433 { 434 struct timespec now = current_fs_time(inode->i_sb); 435 if (inode_unhashed(inode) || !inode->i_nlink || 436 timespec_equal(&inode->i_ctime, &now)) 437 return; 438 439 inode->i_ctime = CURRENT_TIME_SEC; 440 mark_inode_dirty(inode); 441 } 442 443 static int lookup_and_delete_xattr(struct inode *inode, const char *name) 444 { 445 int err = 0; 446 struct dentry *dentry, *xadir; 447 448 xadir = open_xa_dir(inode, XATTR_REPLACE); 449 if (IS_ERR(xadir)) 450 return PTR_ERR(xadir); 451 452 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 453 dentry = lookup_one_len(name, xadir, strlen(name)); 454 if (IS_ERR(dentry)) { 455 err = PTR_ERR(dentry); 456 goto out_dput; 457 } 458 459 if (dentry->d_inode) { 460 reiserfs_write_lock(inode->i_sb); 461 err = xattr_unlink(xadir->d_inode, dentry); 462 reiserfs_write_unlock(inode->i_sb); 463 update_ctime(inode); 464 } 465 466 dput(dentry); 467 out_dput: 468 mutex_unlock(&xadir->d_inode->i_mutex); 469 dput(xadir); 470 return err; 471 } 472 473 474 /* Generic extended attribute operations that can be used by xa plugins */ 475 476 /* 477 * inode->i_mutex: down 478 */ 479 int 480 reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th, 481 struct inode *inode, const char *name, 482 const void *buffer, size_t buffer_size, int flags) 483 { 484 int err = 0; 485 struct dentry *dentry; 486 struct page *page; 487 char *data; 488 size_t file_pos = 0; 489 size_t buffer_pos = 0; 490 size_t new_size; 491 __u32 xahash = 0; 492 493 if (get_inode_sd_version(inode) == STAT_DATA_V1) 494 return -EOPNOTSUPP; 495 496 reiserfs_write_unlock(inode->i_sb); 497 498 if (!buffer) { 499 err = lookup_and_delete_xattr(inode, name); 500 reiserfs_write_lock(inode->i_sb); 501 return err; 502 } 503 504 dentry = xattr_lookup(inode, name, flags); 505 if (IS_ERR(dentry)) { 506 reiserfs_write_lock(inode->i_sb); 507 return PTR_ERR(dentry); 508 } 509 510 down_write(&REISERFS_I(inode)->i_xattr_sem); 511 512 reiserfs_write_lock(inode->i_sb); 513 514 xahash = xattr_hash(buffer, buffer_size); 515 while (buffer_pos < buffer_size || buffer_pos == 0) { 516 size_t chunk; 517 size_t skip = 0; 518 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 519 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 520 chunk = PAGE_CACHE_SIZE; 521 else 522 chunk = buffer_size - buffer_pos; 523 524 page = reiserfs_get_page(dentry->d_inode, file_pos); 525 if (IS_ERR(page)) { 526 err = PTR_ERR(page); 527 goto out_unlock; 528 } 529 530 lock_page(page); 531 data = page_address(page); 532 533 if (file_pos == 0) { 534 struct reiserfs_xattr_header *rxh; 535 skip = file_pos = sizeof(struct reiserfs_xattr_header); 536 if (chunk + skip > PAGE_CACHE_SIZE) 537 chunk = PAGE_CACHE_SIZE - skip; 538 rxh = (struct reiserfs_xattr_header *)data; 539 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 540 rxh->h_hash = cpu_to_le32(xahash); 541 } 542 543 err = __reiserfs_write_begin(page, page_offset, chunk + skip); 544 if (!err) { 545 if (buffer) 546 memcpy(data + skip, buffer + buffer_pos, chunk); 547 err = reiserfs_commit_write(NULL, page, page_offset, 548 page_offset + chunk + 549 skip); 550 } 551 unlock_page(page); 552 reiserfs_put_page(page); 553 buffer_pos += chunk; 554 file_pos += chunk; 555 skip = 0; 556 if (err || buffer_size == 0 || !buffer) 557 break; 558 } 559 560 new_size = buffer_size + sizeof(struct reiserfs_xattr_header); 561 if (!err && new_size < i_size_read(dentry->d_inode)) { 562 struct iattr newattrs = { 563 .ia_ctime = current_fs_time(inode->i_sb), 564 .ia_size = new_size, 565 .ia_valid = ATTR_SIZE | ATTR_CTIME, 566 }; 567 568 reiserfs_write_unlock(inode->i_sb); 569 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 570 inode_dio_wait(dentry->d_inode); 571 reiserfs_write_lock(inode->i_sb); 572 573 err = reiserfs_setattr(dentry, &newattrs); 574 mutex_unlock(&dentry->d_inode->i_mutex); 575 } else 576 update_ctime(inode); 577 out_unlock: 578 up_write(&REISERFS_I(inode)->i_xattr_sem); 579 dput(dentry); 580 return err; 581 } 582 583 /* We need to start a transaction to maintain lock ordering */ 584 int reiserfs_xattr_set(struct inode *inode, const char *name, 585 const void *buffer, size_t buffer_size, int flags) 586 { 587 588 struct reiserfs_transaction_handle th; 589 int error, error2; 590 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); 591 592 if (!(flags & XATTR_REPLACE)) 593 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); 594 595 reiserfs_write_lock(inode->i_sb); 596 error = journal_begin(&th, inode->i_sb, jbegin_count); 597 if (error) { 598 reiserfs_write_unlock(inode->i_sb); 599 return error; 600 } 601 602 error = reiserfs_xattr_set_handle(&th, inode, name, 603 buffer, buffer_size, flags); 604 605 error2 = journal_end(&th, inode->i_sb, jbegin_count); 606 if (error == 0) 607 error = error2; 608 reiserfs_write_unlock(inode->i_sb); 609 610 return error; 611 } 612 613 /* 614 * inode->i_mutex: down 615 */ 616 int 617 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, 618 size_t buffer_size) 619 { 620 ssize_t err = 0; 621 struct dentry *dentry; 622 size_t isize; 623 size_t file_pos = 0; 624 size_t buffer_pos = 0; 625 struct page *page; 626 __u32 hash = 0; 627 628 if (name == NULL) 629 return -EINVAL; 630 631 /* We can't have xattrs attached to v1 items since they don't have 632 * generation numbers */ 633 if (get_inode_sd_version(inode) == STAT_DATA_V1) 634 return -EOPNOTSUPP; 635 636 dentry = xattr_lookup(inode, name, XATTR_REPLACE); 637 if (IS_ERR(dentry)) { 638 err = PTR_ERR(dentry); 639 goto out; 640 } 641 642 down_read(&REISERFS_I(inode)->i_xattr_sem); 643 644 isize = i_size_read(dentry->d_inode); 645 646 /* Just return the size needed */ 647 if (buffer == NULL) { 648 err = isize - sizeof(struct reiserfs_xattr_header); 649 goto out_unlock; 650 } 651 652 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 653 err = -ERANGE; 654 goto out_unlock; 655 } 656 657 while (file_pos < isize) { 658 size_t chunk; 659 char *data; 660 size_t skip = 0; 661 if (isize - file_pos > PAGE_CACHE_SIZE) 662 chunk = PAGE_CACHE_SIZE; 663 else 664 chunk = isize - file_pos; 665 666 page = reiserfs_get_page(dentry->d_inode, file_pos); 667 if (IS_ERR(page)) { 668 err = PTR_ERR(page); 669 goto out_unlock; 670 } 671 672 lock_page(page); 673 data = page_address(page); 674 if (file_pos == 0) { 675 struct reiserfs_xattr_header *rxh = 676 (struct reiserfs_xattr_header *)data; 677 skip = file_pos = sizeof(struct reiserfs_xattr_header); 678 chunk -= skip; 679 /* Magic doesn't match up.. */ 680 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 681 unlock_page(page); 682 reiserfs_put_page(page); 683 reiserfs_warning(inode->i_sb, "jdm-20001", 684 "Invalid magic for xattr (%s) " 685 "associated with %k", name, 686 INODE_PKEY(inode)); 687 err = -EIO; 688 goto out_unlock; 689 } 690 hash = le32_to_cpu(rxh->h_hash); 691 } 692 memcpy(buffer + buffer_pos, data + skip, chunk); 693 unlock_page(page); 694 reiserfs_put_page(page); 695 file_pos += chunk; 696 buffer_pos += chunk; 697 skip = 0; 698 } 699 err = isize - sizeof(struct reiserfs_xattr_header); 700 701 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 702 hash) { 703 reiserfs_warning(inode->i_sb, "jdm-20002", 704 "Invalid hash for xattr (%s) associated " 705 "with %k", name, INODE_PKEY(inode)); 706 err = -EIO; 707 } 708 709 out_unlock: 710 up_read(&REISERFS_I(inode)->i_xattr_sem); 711 dput(dentry); 712 713 out: 714 return err; 715 } 716 717 /* 718 * In order to implement different sets of xattr operations for each xattr 719 * prefix with the generic xattr API, a filesystem should create a 720 * null-terminated array of struct xattr_handler (one for each prefix) and 721 * hang a pointer to it off of the s_xattr field of the superblock. 722 * 723 * The generic_fooxattr() functions will use this list to dispatch xattr 724 * operations to the correct xattr_handler. 725 */ 726 #define for_each_xattr_handler(handlers, handler) \ 727 for ((handler) = *(handlers)++; \ 728 (handler) != NULL; \ 729 (handler) = *(handlers)++) 730 731 /* This is the implementation for the xattr plugin infrastructure */ 732 static inline const struct xattr_handler * 733 find_xattr_handler_prefix(const struct xattr_handler **handlers, 734 const char *name) 735 { 736 const struct xattr_handler *xah; 737 738 if (!handlers) 739 return NULL; 740 741 for_each_xattr_handler(handlers, xah) { 742 if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0) 743 break; 744 } 745 746 return xah; 747 } 748 749 750 /* 751 * Inode operation getxattr() 752 */ 753 ssize_t 754 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 755 size_t size) 756 { 757 const struct xattr_handler *handler; 758 759 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 760 761 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 762 return -EOPNOTSUPP; 763 764 return handler->get(dentry, name, buffer, size, handler->flags); 765 } 766 767 /* 768 * Inode operation setxattr() 769 * 770 * dentry->d_inode->i_mutex down 771 */ 772 int 773 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 774 size_t size, int flags) 775 { 776 const struct xattr_handler *handler; 777 778 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 779 780 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 781 return -EOPNOTSUPP; 782 783 return handler->set(dentry, name, value, size, flags, handler->flags); 784 } 785 786 /* 787 * Inode operation removexattr() 788 * 789 * dentry->d_inode->i_mutex down 790 */ 791 int reiserfs_removexattr(struct dentry *dentry, const char *name) 792 { 793 const struct xattr_handler *handler; 794 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 795 796 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 797 return -EOPNOTSUPP; 798 799 return handler->set(dentry, name, NULL, 0, XATTR_REPLACE, handler->flags); 800 } 801 802 struct listxattr_buf { 803 size_t size; 804 size_t pos; 805 char *buf; 806 struct dentry *dentry; 807 }; 808 809 static int listxattr_filler(void *buf, const char *name, int namelen, 810 loff_t offset, u64 ino, unsigned int d_type) 811 { 812 struct listxattr_buf *b = (struct listxattr_buf *)buf; 813 size_t size; 814 if (name[0] != '.' || 815 (namelen != 1 && (name[1] != '.' || namelen != 2))) { 816 const struct xattr_handler *handler; 817 handler = find_xattr_handler_prefix(b->dentry->d_sb->s_xattr, 818 name); 819 if (!handler) /* Unsupported xattr name */ 820 return 0; 821 if (b->buf) { 822 size = handler->list(b->dentry, b->buf + b->pos, 823 b->size, name, namelen, 824 handler->flags); 825 if (size > b->size) 826 return -ERANGE; 827 } else { 828 size = handler->list(b->dentry, NULL, 0, name, 829 namelen, handler->flags); 830 } 831 832 b->pos += size; 833 } 834 return 0; 835 } 836 837 /* 838 * Inode operation listxattr() 839 * 840 * We totally ignore the generic listxattr here because it would be stupid 841 * not to. Since the xattrs are organized in a directory, we can just 842 * readdir to find them. 843 */ 844 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 845 { 846 struct dentry *dir; 847 int err = 0; 848 loff_t pos = 0; 849 struct listxattr_buf buf = { 850 .dentry = dentry, 851 .buf = buffer, 852 .size = buffer ? size : 0, 853 }; 854 855 if (!dentry->d_inode) 856 return -EINVAL; 857 858 if (!dentry->d_sb->s_xattr || 859 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 860 return -EOPNOTSUPP; 861 862 dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); 863 if (IS_ERR(dir)) { 864 err = PTR_ERR(dir); 865 if (err == -ENODATA) 866 err = 0; /* Not an error if there aren't any xattrs */ 867 goto out; 868 } 869 870 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 871 err = reiserfs_readdir_dentry(dir, &buf, listxattr_filler, &pos); 872 mutex_unlock(&dir->d_inode->i_mutex); 873 874 if (!err) 875 err = buf.pos; 876 877 dput(dir); 878 out: 879 return err; 880 } 881 882 static int create_privroot(struct dentry *dentry) 883 { 884 int err; 885 struct inode *inode = dentry->d_parent->d_inode; 886 WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex)); 887 888 err = xattr_mkdir(inode, dentry, 0700); 889 if (err || !dentry->d_inode) { 890 reiserfs_warning(dentry->d_sb, "jdm-20006", 891 "xattrs/ACLs enabled and couldn't " 892 "find/create .reiserfs_priv. " 893 "Failing mount."); 894 return -EOPNOTSUPP; 895 } 896 897 dentry->d_inode->i_flags |= S_PRIVATE; 898 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 899 "storage.\n", PRIVROOT_NAME); 900 901 return 0; 902 } 903 904 #else 905 int __init reiserfs_xattr_register_handlers(void) { return 0; } 906 void reiserfs_xattr_unregister_handlers(void) {} 907 static int create_privroot(struct dentry *dentry) { return 0; } 908 #endif 909 910 /* Actual operations that are exported to VFS-land */ 911 static const struct xattr_handler *reiserfs_xattr_handlers[] = { 912 #ifdef CONFIG_REISERFS_FS_XATTR 913 &reiserfs_xattr_user_handler, 914 &reiserfs_xattr_trusted_handler, 915 #endif 916 #ifdef CONFIG_REISERFS_FS_SECURITY 917 &reiserfs_xattr_security_handler, 918 #endif 919 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 920 &reiserfs_posix_acl_access_handler, 921 &reiserfs_posix_acl_default_handler, 922 #endif 923 NULL 924 }; 925 926 static int xattr_mount_check(struct super_block *s) 927 { 928 /* We need generation numbers to ensure that the oid mapping is correct 929 * v3.5 filesystems don't have them. */ 930 if (old_format_only(s)) { 931 if (reiserfs_xattrs_optional(s)) { 932 /* Old format filesystem, but optional xattrs have 933 * been enabled. Error out. */ 934 reiserfs_warning(s, "jdm-2005", 935 "xattrs/ACLs not supported " 936 "on pre-v3.6 format filesystems. " 937 "Failing mount."); 938 return -EOPNOTSUPP; 939 } 940 } 941 942 return 0; 943 } 944 945 int reiserfs_permission(struct inode *inode, int mask) 946 { 947 /* 948 * We don't do permission checks on the internal objects. 949 * Permissions are determined by the "owning" object. 950 */ 951 if (IS_PRIVATE(inode)) 952 return 0; 953 954 return generic_permission(inode, mask); 955 } 956 957 static int xattr_hide_revalidate(struct dentry *dentry, unsigned int flags) 958 { 959 return -EPERM; 960 } 961 962 static const struct dentry_operations xattr_lookup_poison_ops = { 963 .d_revalidate = xattr_hide_revalidate, 964 }; 965 966 int reiserfs_lookup_privroot(struct super_block *s) 967 { 968 struct dentry *dentry; 969 int err = 0; 970 971 /* If we don't have the privroot located yet - go find it */ 972 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 973 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 974 strlen(PRIVROOT_NAME)); 975 if (!IS_ERR(dentry)) { 976 REISERFS_SB(s)->priv_root = dentry; 977 d_set_d_op(dentry, &xattr_lookup_poison_ops); 978 if (dentry->d_inode) 979 dentry->d_inode->i_flags |= S_PRIVATE; 980 } else 981 err = PTR_ERR(dentry); 982 mutex_unlock(&s->s_root->d_inode->i_mutex); 983 984 return err; 985 } 986 987 /* We need to take a copy of the mount flags since things like 988 * MS_RDONLY don't get set until *after* we're called. 989 * mount_flags != mount_options */ 990 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 991 { 992 int err = 0; 993 struct dentry *privroot = REISERFS_SB(s)->priv_root; 994 995 err = xattr_mount_check(s); 996 if (err) 997 goto error; 998 999 if (!privroot->d_inode && !(mount_flags & MS_RDONLY)) { 1000 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 1001 err = create_privroot(REISERFS_SB(s)->priv_root); 1002 mutex_unlock(&s->s_root->d_inode->i_mutex); 1003 } 1004 1005 if (privroot->d_inode) { 1006 s->s_xattr = reiserfs_xattr_handlers; 1007 reiserfs_mutex_lock_safe(&privroot->d_inode->i_mutex, s); 1008 if (!REISERFS_SB(s)->xattr_root) { 1009 struct dentry *dentry; 1010 dentry = lookup_one_len(XAROOT_NAME, privroot, 1011 strlen(XAROOT_NAME)); 1012 if (!IS_ERR(dentry)) 1013 REISERFS_SB(s)->xattr_root = dentry; 1014 else 1015 err = PTR_ERR(dentry); 1016 } 1017 mutex_unlock(&privroot->d_inode->i_mutex); 1018 } 1019 1020 error: 1021 if (err) { 1022 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1023 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1024 } 1025 1026 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1027 if (reiserfs_posixacl(s)) 1028 s->s_flags |= MS_POSIXACL; 1029 else 1030 s->s_flags &= ~MS_POSIXACL; 1031 1032 return err; 1033 } 1034