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 dir_context ctx; 175 struct dentry *xadir; 176 int count; 177 struct dentry *dentries[8]; 178 }; 179 180 static int 181 fill_with_dentries(void *buf, const char *name, int namelen, loff_t offset, 182 u64 ino, unsigned int d_type) 183 { 184 struct reiserfs_dentry_buf *dbuf = buf; 185 struct dentry *dentry; 186 WARN_ON_ONCE(!mutex_is_locked(&dbuf->xadir->d_inode->i_mutex)); 187 188 if (dbuf->count == ARRAY_SIZE(dbuf->dentries)) 189 return -ENOSPC; 190 191 if (name[0] == '.' && (namelen < 2 || 192 (namelen == 2 && name[1] == '.'))) 193 return 0; 194 195 dentry = lookup_one_len(name, dbuf->xadir, namelen); 196 if (IS_ERR(dentry)) { 197 return PTR_ERR(dentry); 198 } else if (!dentry->d_inode) { 199 /* A directory entry exists, but no file? */ 200 reiserfs_error(dentry->d_sb, "xattr-20003", 201 "Corrupted directory: xattr %s listed but " 202 "not found for file %s.\n", 203 dentry->d_name.name, dbuf->xadir->d_name.name); 204 dput(dentry); 205 return -EIO; 206 } 207 208 dbuf->dentries[dbuf->count++] = dentry; 209 return 0; 210 } 211 212 static void 213 cleanup_dentry_buf(struct reiserfs_dentry_buf *buf) 214 { 215 int i; 216 for (i = 0; i < buf->count; i++) 217 if (buf->dentries[i]) 218 dput(buf->dentries[i]); 219 } 220 221 static int reiserfs_for_each_xattr(struct inode *inode, 222 int (*action)(struct dentry *, void *), 223 void *data) 224 { 225 struct dentry *dir; 226 int i, err = 0; 227 struct reiserfs_dentry_buf buf = { 228 .ctx.actor = fill_with_dentries, 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.ctx); 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.ctx); 270 } 271 mutex_unlock(&dir->d_inode->i_mutex); 272 273 /* Clean up after a failed readdir */ 274 cleanup_dentry_buf(&buf); 275 276 if (!err) { 277 /* We start a transaction here to avoid a ABBA situation 278 * between the xattr root's i_mutex and the journal lock. 279 * This doesn't incur much additional overhead since the 280 * new transaction will just nest inside the 281 * outer transaction. */ 282 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 283 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); 284 struct reiserfs_transaction_handle th; 285 err = journal_begin(&th, inode->i_sb, blocks); 286 if (!err) { 287 int jerror; 288 reiserfs_mutex_lock_nested_safe( 289 &dir->d_parent->d_inode->i_mutex, 290 I_MUTEX_XATTR, inode->i_sb); 291 err = action(dir, data); 292 jerror = journal_end(&th, inode->i_sb, blocks); 293 mutex_unlock(&dir->d_parent->d_inode->i_mutex); 294 err = jerror ?: err; 295 } 296 } 297 out_dir: 298 dput(dir); 299 out: 300 /* -ENODATA isn't an error */ 301 if (err == -ENODATA) 302 err = 0; 303 return err; 304 } 305 306 static int delete_one_xattr(struct dentry *dentry, void *data) 307 { 308 struct inode *dir = dentry->d_parent->d_inode; 309 310 /* This is the xattr dir, handle specially. */ 311 if (S_ISDIR(dentry->d_inode->i_mode)) 312 return xattr_rmdir(dir, dentry); 313 314 return xattr_unlink(dir, dentry); 315 } 316 317 static int chown_one_xattr(struct dentry *dentry, void *data) 318 { 319 struct iattr *attrs = data; 320 int ia_valid = attrs->ia_valid; 321 int err; 322 323 /* 324 * We only want the ownership bits. Otherwise, we'll do 325 * things like change a directory to a regular file if 326 * ATTR_MODE is set. 327 */ 328 attrs->ia_valid &= (ATTR_UID|ATTR_GID); 329 err = reiserfs_setattr(dentry, attrs); 330 attrs->ia_valid = ia_valid; 331 332 return err; 333 } 334 335 /* No i_mutex, but the inode is unconnected. */ 336 int reiserfs_delete_xattrs(struct inode *inode) 337 { 338 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL); 339 if (err) 340 reiserfs_warning(inode->i_sb, "jdm-20004", 341 "Couldn't delete all xattrs (%d)\n", err); 342 return err; 343 } 344 345 /* inode->i_mutex: down */ 346 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 347 { 348 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs); 349 if (err) 350 reiserfs_warning(inode->i_sb, "jdm-20007", 351 "Couldn't chown all xattrs (%d)\n", err); 352 return err; 353 } 354 355 #ifdef CONFIG_REISERFS_FS_XATTR 356 /* Returns a dentry corresponding to a specific extended attribute file 357 * for the inode. If flags allow, the file is created. Otherwise, a 358 * valid or negative dentry, or an error is returned. */ 359 static struct dentry *xattr_lookup(struct inode *inode, const char *name, 360 int flags) 361 { 362 struct dentry *xadir, *xafile; 363 int err = 0; 364 365 xadir = open_xa_dir(inode, flags); 366 if (IS_ERR(xadir)) 367 return ERR_CAST(xadir); 368 369 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 370 xafile = lookup_one_len(name, xadir, strlen(name)); 371 if (IS_ERR(xafile)) { 372 err = PTR_ERR(xafile); 373 goto out; 374 } 375 376 if (xafile->d_inode && (flags & XATTR_CREATE)) 377 err = -EEXIST; 378 379 if (!xafile->d_inode) { 380 err = -ENODATA; 381 if (xattr_may_create(flags)) 382 err = xattr_create(xadir->d_inode, xafile, 383 0700|S_IFREG); 384 } 385 386 if (err) 387 dput(xafile); 388 out: 389 mutex_unlock(&xadir->d_inode->i_mutex); 390 dput(xadir); 391 if (err) 392 return ERR_PTR(err); 393 return xafile; 394 } 395 396 /* Internal operations on file data */ 397 static inline void reiserfs_put_page(struct page *page) 398 { 399 kunmap(page); 400 page_cache_release(page); 401 } 402 403 static struct page *reiserfs_get_page(struct inode *dir, size_t n) 404 { 405 struct address_space *mapping = dir->i_mapping; 406 struct page *page; 407 /* We can deadlock if we try to free dentries, 408 and an unlink/rmdir has just occurred - GFP_NOFS avoids this */ 409 mapping_set_gfp_mask(mapping, GFP_NOFS); 410 page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); 411 if (!IS_ERR(page)) { 412 kmap(page); 413 if (PageError(page)) 414 goto fail; 415 } 416 return page; 417 418 fail: 419 reiserfs_put_page(page); 420 return ERR_PTR(-EIO); 421 } 422 423 static inline __u32 xattr_hash(const char *msg, int len) 424 { 425 return csum_partial(msg, len, 0); 426 } 427 428 int reiserfs_commit_write(struct file *f, struct page *page, 429 unsigned from, unsigned to); 430 431 static void update_ctime(struct inode *inode) 432 { 433 struct timespec now = current_fs_time(inode->i_sb); 434 if (inode_unhashed(inode) || !inode->i_nlink || 435 timespec_equal(&inode->i_ctime, &now)) 436 return; 437 438 inode->i_ctime = CURRENT_TIME_SEC; 439 mark_inode_dirty(inode); 440 } 441 442 static int lookup_and_delete_xattr(struct inode *inode, const char *name) 443 { 444 int err = 0; 445 struct dentry *dentry, *xadir; 446 447 xadir = open_xa_dir(inode, XATTR_REPLACE); 448 if (IS_ERR(xadir)) 449 return PTR_ERR(xadir); 450 451 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 452 dentry = lookup_one_len(name, xadir, strlen(name)); 453 if (IS_ERR(dentry)) { 454 err = PTR_ERR(dentry); 455 goto out_dput; 456 } 457 458 if (dentry->d_inode) { 459 reiserfs_write_lock(inode->i_sb); 460 err = xattr_unlink(xadir->d_inode, dentry); 461 reiserfs_write_unlock(inode->i_sb); 462 update_ctime(inode); 463 } 464 465 dput(dentry); 466 out_dput: 467 mutex_unlock(&xadir->d_inode->i_mutex); 468 dput(xadir); 469 return err; 470 } 471 472 473 /* Generic extended attribute operations that can be used by xa plugins */ 474 475 /* 476 * inode->i_mutex: down 477 */ 478 int 479 reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th, 480 struct inode *inode, const char *name, 481 const void *buffer, size_t buffer_size, int flags) 482 { 483 int err = 0; 484 struct dentry *dentry; 485 struct page *page; 486 char *data; 487 size_t file_pos = 0; 488 size_t buffer_pos = 0; 489 size_t new_size; 490 __u32 xahash = 0; 491 492 if (get_inode_sd_version(inode) == STAT_DATA_V1) 493 return -EOPNOTSUPP; 494 495 reiserfs_write_unlock(inode->i_sb); 496 497 if (!buffer) { 498 err = lookup_and_delete_xattr(inode, name); 499 reiserfs_write_lock(inode->i_sb); 500 return err; 501 } 502 503 dentry = xattr_lookup(inode, name, flags); 504 if (IS_ERR(dentry)) { 505 reiserfs_write_lock(inode->i_sb); 506 return PTR_ERR(dentry); 507 } 508 509 down_write(&REISERFS_I(inode)->i_xattr_sem); 510 511 reiserfs_write_lock(inode->i_sb); 512 513 xahash = xattr_hash(buffer, buffer_size); 514 while (buffer_pos < buffer_size || buffer_pos == 0) { 515 size_t chunk; 516 size_t skip = 0; 517 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 518 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 519 chunk = PAGE_CACHE_SIZE; 520 else 521 chunk = buffer_size - buffer_pos; 522 523 page = reiserfs_get_page(dentry->d_inode, file_pos); 524 if (IS_ERR(page)) { 525 err = PTR_ERR(page); 526 goto out_unlock; 527 } 528 529 lock_page(page); 530 data = page_address(page); 531 532 if (file_pos == 0) { 533 struct reiserfs_xattr_header *rxh; 534 skip = file_pos = sizeof(struct reiserfs_xattr_header); 535 if (chunk + skip > PAGE_CACHE_SIZE) 536 chunk = PAGE_CACHE_SIZE - skip; 537 rxh = (struct reiserfs_xattr_header *)data; 538 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 539 rxh->h_hash = cpu_to_le32(xahash); 540 } 541 542 err = __reiserfs_write_begin(page, page_offset, chunk + skip); 543 if (!err) { 544 if (buffer) 545 memcpy(data + skip, buffer + buffer_pos, chunk); 546 err = reiserfs_commit_write(NULL, page, page_offset, 547 page_offset + chunk + 548 skip); 549 } 550 unlock_page(page); 551 reiserfs_put_page(page); 552 buffer_pos += chunk; 553 file_pos += chunk; 554 skip = 0; 555 if (err || buffer_size == 0 || !buffer) 556 break; 557 } 558 559 new_size = buffer_size + sizeof(struct reiserfs_xattr_header); 560 if (!err && new_size < i_size_read(dentry->d_inode)) { 561 struct iattr newattrs = { 562 .ia_ctime = current_fs_time(inode->i_sb), 563 .ia_size = new_size, 564 .ia_valid = ATTR_SIZE | ATTR_CTIME, 565 }; 566 567 reiserfs_write_unlock(inode->i_sb); 568 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 569 inode_dio_wait(dentry->d_inode); 570 reiserfs_write_lock(inode->i_sb); 571 572 err = reiserfs_setattr(dentry, &newattrs); 573 mutex_unlock(&dentry->d_inode->i_mutex); 574 } else 575 update_ctime(inode); 576 out_unlock: 577 up_write(&REISERFS_I(inode)->i_xattr_sem); 578 dput(dentry); 579 return err; 580 } 581 582 /* We need to start a transaction to maintain lock ordering */ 583 int reiserfs_xattr_set(struct inode *inode, const char *name, 584 const void *buffer, size_t buffer_size, int flags) 585 { 586 587 struct reiserfs_transaction_handle th; 588 int error, error2; 589 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); 590 591 if (!(flags & XATTR_REPLACE)) 592 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); 593 594 reiserfs_write_lock(inode->i_sb); 595 error = journal_begin(&th, inode->i_sb, jbegin_count); 596 if (error) { 597 reiserfs_write_unlock(inode->i_sb); 598 return error; 599 } 600 601 error = reiserfs_xattr_set_handle(&th, inode, name, 602 buffer, buffer_size, flags); 603 604 error2 = journal_end(&th, inode->i_sb, jbegin_count); 605 if (error == 0) 606 error = error2; 607 reiserfs_write_unlock(inode->i_sb); 608 609 return error; 610 } 611 612 /* 613 * inode->i_mutex: down 614 */ 615 int 616 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, 617 size_t buffer_size) 618 { 619 ssize_t err = 0; 620 struct dentry *dentry; 621 size_t isize; 622 size_t file_pos = 0; 623 size_t buffer_pos = 0; 624 struct page *page; 625 __u32 hash = 0; 626 627 if (name == NULL) 628 return -EINVAL; 629 630 /* We can't have xattrs attached to v1 items since they don't have 631 * generation numbers */ 632 if (get_inode_sd_version(inode) == STAT_DATA_V1) 633 return -EOPNOTSUPP; 634 635 dentry = xattr_lookup(inode, name, XATTR_REPLACE); 636 if (IS_ERR(dentry)) { 637 err = PTR_ERR(dentry); 638 goto out; 639 } 640 641 down_read(&REISERFS_I(inode)->i_xattr_sem); 642 643 isize = i_size_read(dentry->d_inode); 644 645 /* Just return the size needed */ 646 if (buffer == NULL) { 647 err = isize - sizeof(struct reiserfs_xattr_header); 648 goto out_unlock; 649 } 650 651 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 652 err = -ERANGE; 653 goto out_unlock; 654 } 655 656 while (file_pos < isize) { 657 size_t chunk; 658 char *data; 659 size_t skip = 0; 660 if (isize - file_pos > PAGE_CACHE_SIZE) 661 chunk = PAGE_CACHE_SIZE; 662 else 663 chunk = isize - file_pos; 664 665 page = reiserfs_get_page(dentry->d_inode, file_pos); 666 if (IS_ERR(page)) { 667 err = PTR_ERR(page); 668 goto out_unlock; 669 } 670 671 lock_page(page); 672 data = page_address(page); 673 if (file_pos == 0) { 674 struct reiserfs_xattr_header *rxh = 675 (struct reiserfs_xattr_header *)data; 676 skip = file_pos = sizeof(struct reiserfs_xattr_header); 677 chunk -= skip; 678 /* Magic doesn't match up.. */ 679 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 680 unlock_page(page); 681 reiserfs_put_page(page); 682 reiserfs_warning(inode->i_sb, "jdm-20001", 683 "Invalid magic for xattr (%s) " 684 "associated with %k", name, 685 INODE_PKEY(inode)); 686 err = -EIO; 687 goto out_unlock; 688 } 689 hash = le32_to_cpu(rxh->h_hash); 690 } 691 memcpy(buffer + buffer_pos, data + skip, chunk); 692 unlock_page(page); 693 reiserfs_put_page(page); 694 file_pos += chunk; 695 buffer_pos += chunk; 696 skip = 0; 697 } 698 err = isize - sizeof(struct reiserfs_xattr_header); 699 700 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 701 hash) { 702 reiserfs_warning(inode->i_sb, "jdm-20002", 703 "Invalid hash for xattr (%s) associated " 704 "with %k", name, INODE_PKEY(inode)); 705 err = -EIO; 706 } 707 708 out_unlock: 709 up_read(&REISERFS_I(inode)->i_xattr_sem); 710 dput(dentry); 711 712 out: 713 return err; 714 } 715 716 /* 717 * In order to implement different sets of xattr operations for each xattr 718 * prefix with the generic xattr API, a filesystem should create a 719 * null-terminated array of struct xattr_handler (one for each prefix) and 720 * hang a pointer to it off of the s_xattr field of the superblock. 721 * 722 * The generic_fooxattr() functions will use this list to dispatch xattr 723 * operations to the correct xattr_handler. 724 */ 725 #define for_each_xattr_handler(handlers, handler) \ 726 for ((handler) = *(handlers)++; \ 727 (handler) != NULL; \ 728 (handler) = *(handlers)++) 729 730 /* This is the implementation for the xattr plugin infrastructure */ 731 static inline const struct xattr_handler * 732 find_xattr_handler_prefix(const struct xattr_handler **handlers, 733 const char *name) 734 { 735 const struct xattr_handler *xah; 736 737 if (!handlers) 738 return NULL; 739 740 for_each_xattr_handler(handlers, xah) { 741 if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0) 742 break; 743 } 744 745 return xah; 746 } 747 748 749 /* 750 * Inode operation getxattr() 751 */ 752 ssize_t 753 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 754 size_t size) 755 { 756 const struct xattr_handler *handler; 757 758 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 759 760 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 761 return -EOPNOTSUPP; 762 763 return handler->get(dentry, name, buffer, size, handler->flags); 764 } 765 766 /* 767 * Inode operation setxattr() 768 * 769 * dentry->d_inode->i_mutex down 770 */ 771 int 772 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 773 size_t size, int flags) 774 { 775 const struct xattr_handler *handler; 776 777 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 778 779 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 780 return -EOPNOTSUPP; 781 782 return handler->set(dentry, name, value, size, flags, handler->flags); 783 } 784 785 /* 786 * Inode operation removexattr() 787 * 788 * dentry->d_inode->i_mutex down 789 */ 790 int reiserfs_removexattr(struct dentry *dentry, const char *name) 791 { 792 const struct xattr_handler *handler; 793 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 794 795 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 796 return -EOPNOTSUPP; 797 798 return handler->set(dentry, name, NULL, 0, XATTR_REPLACE, handler->flags); 799 } 800 801 struct listxattr_buf { 802 struct dir_context ctx; 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 struct listxattr_buf buf = { 849 .ctx.actor = listxattr_filler, 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.ctx); 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