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/stat.h> 50 #include <linux/quotaops.h> 51 #include <linux/security.h> 52 53 #define PRIVROOT_NAME ".reiserfs_priv" 54 #define XAROOT_NAME "xattrs" 55 56 57 /* Helpers for inode ops. We do this so that we don't have all the VFS 58 * overhead and also for proper i_mutex annotation. 59 * dir->i_mutex must be held for all of them. */ 60 #ifdef CONFIG_REISERFS_FS_XATTR 61 static int xattr_create(struct inode *dir, struct dentry *dentry, int mode) 62 { 63 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 64 vfs_dq_init(dir); 65 return dir->i_op->create(dir, dentry, mode, NULL); 66 } 67 #endif 68 69 static int xattr_mkdir(struct inode *dir, struct dentry *dentry, int mode) 70 { 71 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 72 vfs_dq_init(dir); 73 return dir->i_op->mkdir(dir, dentry, mode); 74 } 75 76 /* We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr 77 * mutation ops aren't called during rename or splace, which are the 78 * only other users of I_MUTEX_CHILD. It violates the ordering, but that's 79 * better than allocating another subclass just for this code. */ 80 static int xattr_unlink(struct inode *dir, struct dentry *dentry) 81 { 82 int error; 83 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 84 vfs_dq_init(dir); 85 86 reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex, 87 I_MUTEX_CHILD, dir->i_sb); 88 error = dir->i_op->unlink(dir, dentry); 89 mutex_unlock(&dentry->d_inode->i_mutex); 90 91 if (!error) 92 d_delete(dentry); 93 return error; 94 } 95 96 static int xattr_rmdir(struct inode *dir, struct dentry *dentry) 97 { 98 int error; 99 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 100 vfs_dq_init(dir); 101 102 reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex, 103 I_MUTEX_CHILD, dir->i_sb); 104 dentry_unhash(dentry); 105 error = dir->i_op->rmdir(dir, dentry); 106 if (!error) 107 dentry->d_inode->i_flags |= S_DEAD; 108 mutex_unlock(&dentry->d_inode->i_mutex); 109 if (!error) 110 d_delete(dentry); 111 dput(dentry); 112 113 return error; 114 } 115 116 #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE) 117 118 static struct dentry *open_xa_root(struct super_block *sb, int flags) 119 { 120 struct dentry *privroot = REISERFS_SB(sb)->priv_root; 121 struct dentry *xaroot; 122 if (!privroot->d_inode) 123 return ERR_PTR(-ENODATA); 124 125 mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR); 126 127 xaroot = dget(REISERFS_SB(sb)->xattr_root); 128 if (!xaroot) 129 xaroot = ERR_PTR(-ENODATA); 130 else if (!xaroot->d_inode) { 131 int err = -ENODATA; 132 if (xattr_may_create(flags)) 133 err = xattr_mkdir(privroot->d_inode, xaroot, 0700); 134 if (err) { 135 dput(xaroot); 136 xaroot = ERR_PTR(err); 137 } 138 } 139 140 mutex_unlock(&privroot->d_inode->i_mutex); 141 return xaroot; 142 } 143 144 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 145 { 146 struct dentry *xaroot, *xadir; 147 char namebuf[17]; 148 149 xaroot = open_xa_root(inode->i_sb, flags); 150 if (IS_ERR(xaroot)) 151 return xaroot; 152 153 snprintf(namebuf, sizeof(namebuf), "%X.%X", 154 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 155 inode->i_generation); 156 157 mutex_lock_nested(&xaroot->d_inode->i_mutex, I_MUTEX_XATTR); 158 159 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); 160 if (!IS_ERR(xadir) && !xadir->d_inode) { 161 int err = -ENODATA; 162 if (xattr_may_create(flags)) 163 err = xattr_mkdir(xaroot->d_inode, xadir, 0700); 164 if (err) { 165 dput(xadir); 166 xadir = ERR_PTR(err); 167 } 168 } 169 170 mutex_unlock(&xaroot->d_inode->i_mutex); 171 dput(xaroot); 172 return xadir; 173 } 174 175 /* The following are side effects of other operations that aren't explicitly 176 * modifying extended attributes. This includes operations such as permissions 177 * or ownership changes, object deletions, etc. */ 178 struct reiserfs_dentry_buf { 179 struct dentry *xadir; 180 int count; 181 struct dentry *dentries[8]; 182 }; 183 184 static int 185 fill_with_dentries(void *buf, const char *name, int namelen, loff_t offset, 186 u64 ino, unsigned int d_type) 187 { 188 struct reiserfs_dentry_buf *dbuf = buf; 189 struct dentry *dentry; 190 WARN_ON_ONCE(!mutex_is_locked(&dbuf->xadir->d_inode->i_mutex)); 191 192 if (dbuf->count == ARRAY_SIZE(dbuf->dentries)) 193 return -ENOSPC; 194 195 if (name[0] == '.' && (name[1] == '\0' || 196 (name[1] == '.' && name[2] == '\0'))) 197 return 0; 198 199 dentry = lookup_one_len(name, dbuf->xadir, namelen); 200 if (IS_ERR(dentry)) { 201 return PTR_ERR(dentry); 202 } else if (!dentry->d_inode) { 203 /* A directory entry exists, but no file? */ 204 reiserfs_error(dentry->d_sb, "xattr-20003", 205 "Corrupted directory: xattr %s listed but " 206 "not found for file %s.\n", 207 dentry->d_name.name, dbuf->xadir->d_name.name); 208 dput(dentry); 209 return -EIO; 210 } 211 212 dbuf->dentries[dbuf->count++] = dentry; 213 return 0; 214 } 215 216 static void 217 cleanup_dentry_buf(struct reiserfs_dentry_buf *buf) 218 { 219 int i; 220 for (i = 0; i < buf->count; i++) 221 if (buf->dentries[i]) 222 dput(buf->dentries[i]); 223 } 224 225 static int reiserfs_for_each_xattr(struct inode *inode, 226 int (*action)(struct dentry *, void *), 227 void *data) 228 { 229 struct dentry *dir; 230 int i, err = 0; 231 loff_t pos = 0; 232 struct reiserfs_dentry_buf buf = { 233 .count = 0, 234 }; 235 236 /* Skip out, an xattr has no xattrs associated with it */ 237 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 238 return 0; 239 240 reiserfs_write_unlock(inode->i_sb); 241 dir = open_xa_dir(inode, XATTR_REPLACE); 242 if (IS_ERR(dir)) { 243 err = PTR_ERR(dir); 244 reiserfs_write_lock(inode->i_sb); 245 goto out; 246 } else if (!dir->d_inode) { 247 err = 0; 248 reiserfs_write_lock(inode->i_sb); 249 goto out_dir; 250 } 251 252 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 253 254 reiserfs_write_lock(inode->i_sb); 255 256 buf.xadir = dir; 257 err = reiserfs_readdir_dentry(dir, &buf, fill_with_dentries, &pos); 258 while ((err == 0 || err == -ENOSPC) && buf.count) { 259 err = 0; 260 261 for (i = 0; i < buf.count && buf.dentries[i]; i++) { 262 int lerr = 0; 263 struct dentry *dentry = buf.dentries[i]; 264 265 if (err == 0 && !S_ISDIR(dentry->d_inode->i_mode)) 266 lerr = action(dentry, data); 267 268 dput(dentry); 269 buf.dentries[i] = NULL; 270 err = lerr ?: err; 271 } 272 buf.count = 0; 273 if (!err) 274 err = reiserfs_readdir_dentry(dir, &buf, 275 fill_with_dentries, &pos); 276 } 277 mutex_unlock(&dir->d_inode->i_mutex); 278 279 /* Clean up after a failed readdir */ 280 cleanup_dentry_buf(&buf); 281 282 if (!err) { 283 /* We start a transaction here to avoid a ABBA situation 284 * between the xattr root's i_mutex and the journal lock. 285 * This doesn't incur much additional overhead since the 286 * new transaction will just nest inside the 287 * outer transaction. */ 288 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 289 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); 290 struct reiserfs_transaction_handle th; 291 err = journal_begin(&th, inode->i_sb, blocks); 292 if (!err) { 293 int jerror; 294 reiserfs_mutex_lock_nested_safe( 295 &dir->d_parent->d_inode->i_mutex, 296 I_MUTEX_XATTR, inode->i_sb); 297 err = action(dir, data); 298 jerror = journal_end(&th, inode->i_sb, blocks); 299 mutex_unlock(&dir->d_parent->d_inode->i_mutex); 300 err = jerror ?: err; 301 } 302 } 303 out_dir: 304 dput(dir); 305 out: 306 /* -ENODATA isn't an error */ 307 if (err == -ENODATA) 308 err = 0; 309 return err; 310 } 311 312 static int delete_one_xattr(struct dentry *dentry, void *data) 313 { 314 struct inode *dir = dentry->d_parent->d_inode; 315 316 /* This is the xattr dir, handle specially. */ 317 if (S_ISDIR(dentry->d_inode->i_mode)) 318 return xattr_rmdir(dir, dentry); 319 320 return xattr_unlink(dir, dentry); 321 } 322 323 static int chown_one_xattr(struct dentry *dentry, void *data) 324 { 325 struct iattr *attrs = data; 326 return reiserfs_setattr(dentry, attrs); 327 } 328 329 /* No i_mutex, but the inode is unconnected. */ 330 int reiserfs_delete_xattrs(struct inode *inode) 331 { 332 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL); 333 if (err) 334 reiserfs_warning(inode->i_sb, "jdm-20004", 335 "Couldn't delete all xattrs (%d)\n", err); 336 return err; 337 } 338 339 /* inode->i_mutex: down */ 340 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 341 { 342 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs); 343 if (err) 344 reiserfs_warning(inode->i_sb, "jdm-20007", 345 "Couldn't chown all xattrs (%d)\n", err); 346 return err; 347 } 348 349 #ifdef CONFIG_REISERFS_FS_XATTR 350 /* Returns a dentry corresponding to a specific extended attribute file 351 * for the inode. If flags allow, the file is created. Otherwise, a 352 * valid or negative dentry, or an error is returned. */ 353 static struct dentry *xattr_lookup(struct inode *inode, const char *name, 354 int flags) 355 { 356 struct dentry *xadir, *xafile; 357 int err = 0; 358 359 xadir = open_xa_dir(inode, flags); 360 if (IS_ERR(xadir)) 361 return ERR_CAST(xadir); 362 363 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 364 xafile = lookup_one_len(name, xadir, strlen(name)); 365 if (IS_ERR(xafile)) { 366 err = PTR_ERR(xafile); 367 goto out; 368 } 369 370 if (xafile->d_inode && (flags & XATTR_CREATE)) 371 err = -EEXIST; 372 373 if (!xafile->d_inode) { 374 err = -ENODATA; 375 if (xattr_may_create(flags)) 376 err = xattr_create(xadir->d_inode, xafile, 377 0700|S_IFREG); 378 } 379 380 if (err) 381 dput(xafile); 382 out: 383 mutex_unlock(&xadir->d_inode->i_mutex); 384 dput(xadir); 385 if (err) 386 return ERR_PTR(err); 387 return xafile; 388 } 389 390 /* Internal operations on file data */ 391 static inline void reiserfs_put_page(struct page *page) 392 { 393 kunmap(page); 394 page_cache_release(page); 395 } 396 397 static struct page *reiserfs_get_page(struct inode *dir, size_t n) 398 { 399 struct address_space *mapping = dir->i_mapping; 400 struct page *page; 401 /* We can deadlock if we try to free dentries, 402 and an unlink/rmdir has just occured - GFP_NOFS avoids this */ 403 mapping_set_gfp_mask(mapping, GFP_NOFS); 404 page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); 405 if (!IS_ERR(page)) { 406 kmap(page); 407 if (PageError(page)) 408 goto fail; 409 } 410 return page; 411 412 fail: 413 reiserfs_put_page(page); 414 return ERR_PTR(-EIO); 415 } 416 417 static inline __u32 xattr_hash(const char *msg, int len) 418 { 419 return csum_partial(msg, len, 0); 420 } 421 422 int reiserfs_commit_write(struct file *f, struct page *page, 423 unsigned from, unsigned to); 424 int reiserfs_prepare_write(struct file *f, struct page *page, 425 unsigned from, unsigned to); 426 427 static void update_ctime(struct inode *inode) 428 { 429 struct timespec now = current_fs_time(inode->i_sb); 430 if (hlist_unhashed(&inode->i_hash) || !inode->i_nlink || 431 timespec_equal(&inode->i_ctime, &now)) 432 return; 433 434 inode->i_ctime = CURRENT_TIME_SEC; 435 mark_inode_dirty(inode); 436 } 437 438 static int lookup_and_delete_xattr(struct inode *inode, const char *name) 439 { 440 int err = 0; 441 struct dentry *dentry, *xadir; 442 443 xadir = open_xa_dir(inode, XATTR_REPLACE); 444 if (IS_ERR(xadir)) 445 return PTR_ERR(xadir); 446 447 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 448 dentry = lookup_one_len(name, xadir, strlen(name)); 449 if (IS_ERR(dentry)) { 450 err = PTR_ERR(dentry); 451 goto out_dput; 452 } 453 454 if (dentry->d_inode) { 455 err = xattr_unlink(xadir->d_inode, dentry); 456 update_ctime(inode); 457 } 458 459 dput(dentry); 460 out_dput: 461 mutex_unlock(&xadir->d_inode->i_mutex); 462 dput(xadir); 463 return err; 464 } 465 466 467 /* Generic extended attribute operations that can be used by xa plugins */ 468 469 /* 470 * inode->i_mutex: down 471 */ 472 int 473 reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th, 474 struct inode *inode, const char *name, 475 const void *buffer, size_t buffer_size, int flags) 476 { 477 int err = 0; 478 struct dentry *dentry; 479 struct page *page; 480 char *data; 481 size_t file_pos = 0; 482 size_t buffer_pos = 0; 483 size_t new_size; 484 __u32 xahash = 0; 485 486 if (get_inode_sd_version(inode) == STAT_DATA_V1) 487 return -EOPNOTSUPP; 488 489 if (!buffer) 490 return lookup_and_delete_xattr(inode, name); 491 492 reiserfs_write_unlock(inode->i_sb); 493 dentry = xattr_lookup(inode, name, flags); 494 if (IS_ERR(dentry)) { 495 reiserfs_write_lock(inode->i_sb); 496 return PTR_ERR(dentry); 497 } 498 499 down_read(&REISERFS_I(inode)->i_xattr_sem); 500 501 reiserfs_write_lock(inode->i_sb); 502 503 xahash = xattr_hash(buffer, buffer_size); 504 while (buffer_pos < buffer_size || buffer_pos == 0) { 505 size_t chunk; 506 size_t skip = 0; 507 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 508 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 509 chunk = PAGE_CACHE_SIZE; 510 else 511 chunk = buffer_size - buffer_pos; 512 513 page = reiserfs_get_page(dentry->d_inode, file_pos); 514 if (IS_ERR(page)) { 515 err = PTR_ERR(page); 516 goto out_unlock; 517 } 518 519 lock_page(page); 520 data = page_address(page); 521 522 if (file_pos == 0) { 523 struct reiserfs_xattr_header *rxh; 524 skip = file_pos = sizeof(struct reiserfs_xattr_header); 525 if (chunk + skip > PAGE_CACHE_SIZE) 526 chunk = PAGE_CACHE_SIZE - skip; 527 rxh = (struct reiserfs_xattr_header *)data; 528 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 529 rxh->h_hash = cpu_to_le32(xahash); 530 } 531 532 err = reiserfs_prepare_write(NULL, page, page_offset, 533 page_offset + chunk + skip); 534 if (!err) { 535 if (buffer) 536 memcpy(data + skip, buffer + buffer_pos, chunk); 537 err = reiserfs_commit_write(NULL, page, page_offset, 538 page_offset + chunk + 539 skip); 540 } 541 unlock_page(page); 542 reiserfs_put_page(page); 543 buffer_pos += chunk; 544 file_pos += chunk; 545 skip = 0; 546 if (err || buffer_size == 0 || !buffer) 547 break; 548 } 549 550 new_size = buffer_size + sizeof(struct reiserfs_xattr_header); 551 if (!err && new_size < i_size_read(dentry->d_inode)) { 552 struct iattr newattrs = { 553 .ia_ctime = current_fs_time(inode->i_sb), 554 .ia_size = buffer_size, 555 .ia_valid = ATTR_SIZE | ATTR_CTIME, 556 }; 557 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 558 down_write(&dentry->d_inode->i_alloc_sem); 559 err = reiserfs_setattr(dentry, &newattrs); 560 up_write(&dentry->d_inode->i_alloc_sem); 561 mutex_unlock(&dentry->d_inode->i_mutex); 562 } else 563 update_ctime(inode); 564 out_unlock: 565 up_write(&REISERFS_I(inode)->i_xattr_sem); 566 dput(dentry); 567 return err; 568 } 569 570 /* We need to start a transaction to maintain lock ordering */ 571 int reiserfs_xattr_set(struct inode *inode, const char *name, 572 const void *buffer, size_t buffer_size, int flags) 573 { 574 575 struct reiserfs_transaction_handle th; 576 int error, error2; 577 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); 578 579 if (!(flags & XATTR_REPLACE)) 580 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); 581 582 reiserfs_write_lock(inode->i_sb); 583 error = journal_begin(&th, inode->i_sb, jbegin_count); 584 if (error) { 585 reiserfs_write_unlock(inode->i_sb); 586 return error; 587 } 588 589 error = reiserfs_xattr_set_handle(&th, inode, name, 590 buffer, buffer_size, flags); 591 592 error2 = journal_end(&th, inode->i_sb, jbegin_count); 593 if (error == 0) 594 error = error2; 595 reiserfs_write_unlock(inode->i_sb); 596 597 return error; 598 } 599 600 /* 601 * inode->i_mutex: down 602 */ 603 int 604 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, 605 size_t buffer_size) 606 { 607 ssize_t err = 0; 608 struct dentry *dentry; 609 size_t isize; 610 size_t file_pos = 0; 611 size_t buffer_pos = 0; 612 struct page *page; 613 __u32 hash = 0; 614 615 if (name == NULL) 616 return -EINVAL; 617 618 /* We can't have xattrs attached to v1 items since they don't have 619 * generation numbers */ 620 if (get_inode_sd_version(inode) == STAT_DATA_V1) 621 return -EOPNOTSUPP; 622 623 dentry = xattr_lookup(inode, name, XATTR_REPLACE); 624 if (IS_ERR(dentry)) { 625 err = PTR_ERR(dentry); 626 goto out; 627 } 628 629 down_read(&REISERFS_I(inode)->i_xattr_sem); 630 631 isize = i_size_read(dentry->d_inode); 632 633 /* Just return the size needed */ 634 if (buffer == NULL) { 635 err = isize - sizeof(struct reiserfs_xattr_header); 636 goto out_unlock; 637 } 638 639 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 640 err = -ERANGE; 641 goto out_unlock; 642 } 643 644 while (file_pos < isize) { 645 size_t chunk; 646 char *data; 647 size_t skip = 0; 648 if (isize - file_pos > PAGE_CACHE_SIZE) 649 chunk = PAGE_CACHE_SIZE; 650 else 651 chunk = isize - file_pos; 652 653 page = reiserfs_get_page(dentry->d_inode, file_pos); 654 if (IS_ERR(page)) { 655 err = PTR_ERR(page); 656 goto out_unlock; 657 } 658 659 lock_page(page); 660 data = page_address(page); 661 if (file_pos == 0) { 662 struct reiserfs_xattr_header *rxh = 663 (struct reiserfs_xattr_header *)data; 664 skip = file_pos = sizeof(struct reiserfs_xattr_header); 665 chunk -= skip; 666 /* Magic doesn't match up.. */ 667 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 668 unlock_page(page); 669 reiserfs_put_page(page); 670 reiserfs_warning(inode->i_sb, "jdm-20001", 671 "Invalid magic for xattr (%s) " 672 "associated with %k", name, 673 INODE_PKEY(inode)); 674 err = -EIO; 675 goto out_unlock; 676 } 677 hash = le32_to_cpu(rxh->h_hash); 678 } 679 memcpy(buffer + buffer_pos, data + skip, chunk); 680 unlock_page(page); 681 reiserfs_put_page(page); 682 file_pos += chunk; 683 buffer_pos += chunk; 684 skip = 0; 685 } 686 err = isize - sizeof(struct reiserfs_xattr_header); 687 688 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 689 hash) { 690 reiserfs_warning(inode->i_sb, "jdm-20002", 691 "Invalid hash for xattr (%s) associated " 692 "with %k", name, INODE_PKEY(inode)); 693 err = -EIO; 694 } 695 696 out_unlock: 697 up_read(&REISERFS_I(inode)->i_xattr_sem); 698 dput(dentry); 699 700 out: 701 return err; 702 } 703 704 /* 705 * In order to implement different sets of xattr operations for each xattr 706 * prefix with the generic xattr API, a filesystem should create a 707 * null-terminated array of struct xattr_handler (one for each prefix) and 708 * hang a pointer to it off of the s_xattr field of the superblock. 709 * 710 * The generic_fooxattr() functions will use this list to dispatch xattr 711 * operations to the correct xattr_handler. 712 */ 713 #define for_each_xattr_handler(handlers, handler) \ 714 for ((handler) = *(handlers)++; \ 715 (handler) != NULL; \ 716 (handler) = *(handlers)++) 717 718 /* This is the implementation for the xattr plugin infrastructure */ 719 static inline struct xattr_handler * 720 find_xattr_handler_prefix(struct xattr_handler **handlers, 721 const char *name) 722 { 723 struct xattr_handler *xah; 724 725 if (!handlers) 726 return NULL; 727 728 for_each_xattr_handler(handlers, xah) { 729 if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0) 730 break; 731 } 732 733 return xah; 734 } 735 736 737 /* 738 * Inode operation getxattr() 739 */ 740 ssize_t 741 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 742 size_t size) 743 { 744 struct xattr_handler *handler; 745 746 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 747 748 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 749 return -EOPNOTSUPP; 750 751 return handler->get(dentry, name, buffer, size, handler->flags); 752 } 753 754 /* 755 * Inode operation setxattr() 756 * 757 * dentry->d_inode->i_mutex down 758 */ 759 int 760 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 761 size_t size, int flags) 762 { 763 struct xattr_handler *handler; 764 765 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 766 767 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 768 return -EOPNOTSUPP; 769 770 return handler->set(dentry, name, value, size, flags, handler->flags); 771 } 772 773 /* 774 * Inode operation removexattr() 775 * 776 * dentry->d_inode->i_mutex down 777 */ 778 int reiserfs_removexattr(struct dentry *dentry, const char *name) 779 { 780 struct xattr_handler *handler; 781 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 782 783 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 784 return -EOPNOTSUPP; 785 786 return handler->set(dentry, name, NULL, 0, XATTR_REPLACE, handler->flags); 787 } 788 789 struct listxattr_buf { 790 size_t size; 791 size_t pos; 792 char *buf; 793 struct dentry *dentry; 794 }; 795 796 static int listxattr_filler(void *buf, const char *name, int namelen, 797 loff_t offset, u64 ino, unsigned int d_type) 798 { 799 struct listxattr_buf *b = (struct listxattr_buf *)buf; 800 size_t size; 801 if (name[0] != '.' || 802 (namelen != 1 && (name[1] != '.' || namelen != 2))) { 803 struct xattr_handler *handler; 804 handler = find_xattr_handler_prefix(b->dentry->d_sb->s_xattr, 805 name); 806 if (!handler) /* Unsupported xattr name */ 807 return 0; 808 if (b->buf) { 809 size = handler->list(b->dentry, b->buf + b->pos, 810 b->size, name, namelen, 811 handler->flags); 812 if (size > b->size) 813 return -ERANGE; 814 } else { 815 size = handler->list(b->dentry, NULL, 0, name, 816 namelen, handler->flags); 817 } 818 819 b->pos += size; 820 } 821 return 0; 822 } 823 824 /* 825 * Inode operation listxattr() 826 * 827 * We totally ignore the generic listxattr here because it would be stupid 828 * not to. Since the xattrs are organized in a directory, we can just 829 * readdir to find them. 830 */ 831 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 832 { 833 struct dentry *dir; 834 int err = 0; 835 loff_t pos = 0; 836 struct listxattr_buf buf = { 837 .dentry = dentry, 838 .buf = buffer, 839 .size = buffer ? size : 0, 840 }; 841 842 if (!dentry->d_inode) 843 return -EINVAL; 844 845 if (!dentry->d_sb->s_xattr || 846 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 847 return -EOPNOTSUPP; 848 849 dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); 850 if (IS_ERR(dir)) { 851 err = PTR_ERR(dir); 852 if (err == -ENODATA) 853 err = 0; /* Not an error if there aren't any xattrs */ 854 goto out; 855 } 856 857 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 858 err = reiserfs_readdir_dentry(dir, &buf, listxattr_filler, &pos); 859 mutex_unlock(&dir->d_inode->i_mutex); 860 861 if (!err) 862 err = buf.pos; 863 864 dput(dir); 865 out: 866 return err; 867 } 868 869 static int reiserfs_check_acl(struct inode *inode, int mask) 870 { 871 struct posix_acl *acl; 872 int error = -EAGAIN; /* do regular unix permission checks by default */ 873 874 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 875 876 if (acl) { 877 if (!IS_ERR(acl)) { 878 error = posix_acl_permission(inode, acl, mask); 879 posix_acl_release(acl); 880 } else if (PTR_ERR(acl) != -ENODATA) 881 error = PTR_ERR(acl); 882 } 883 884 return error; 885 } 886 887 static int create_privroot(struct dentry *dentry) 888 { 889 int err; 890 struct inode *inode = dentry->d_parent->d_inode; 891 WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex)); 892 893 err = xattr_mkdir(inode, dentry, 0700); 894 if (err || !dentry->d_inode) { 895 reiserfs_warning(dentry->d_sb, "jdm-20006", 896 "xattrs/ACLs enabled and couldn't " 897 "find/create .reiserfs_priv. " 898 "Failing mount."); 899 return -EOPNOTSUPP; 900 } 901 902 dentry->d_inode->i_flags |= S_PRIVATE; 903 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 904 "storage.\n", PRIVROOT_NAME); 905 906 return 0; 907 } 908 909 #else 910 int __init reiserfs_xattr_register_handlers(void) { return 0; } 911 void reiserfs_xattr_unregister_handlers(void) {} 912 static int create_privroot(struct dentry *dentry) { return 0; } 913 #endif 914 915 /* Actual operations that are exported to VFS-land */ 916 struct xattr_handler *reiserfs_xattr_handlers[] = { 917 #ifdef CONFIG_REISERFS_FS_XATTR 918 &reiserfs_xattr_user_handler, 919 &reiserfs_xattr_trusted_handler, 920 #endif 921 #ifdef CONFIG_REISERFS_FS_SECURITY 922 &reiserfs_xattr_security_handler, 923 #endif 924 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 925 &reiserfs_posix_acl_access_handler, 926 &reiserfs_posix_acl_default_handler, 927 #endif 928 NULL 929 }; 930 931 static int xattr_mount_check(struct super_block *s) 932 { 933 /* We need generation numbers to ensure that the oid mapping is correct 934 * v3.5 filesystems don't have them. */ 935 if (old_format_only(s)) { 936 if (reiserfs_xattrs_optional(s)) { 937 /* Old format filesystem, but optional xattrs have 938 * been enabled. Error out. */ 939 reiserfs_warning(s, "jdm-2005", 940 "xattrs/ACLs not supported " 941 "on pre-v3.6 format filesystems. " 942 "Failing mount."); 943 return -EOPNOTSUPP; 944 } 945 } 946 947 return 0; 948 } 949 950 int reiserfs_permission(struct inode *inode, int mask) 951 { 952 /* 953 * We don't do permission checks on the internal objects. 954 * Permissions are determined by the "owning" object. 955 */ 956 if (IS_PRIVATE(inode)) 957 return 0; 958 959 #ifdef CONFIG_REISERFS_FS_XATTR 960 /* 961 * Stat data v1 doesn't support ACLs. 962 */ 963 if (get_inode_sd_version(inode) != STAT_DATA_V1) 964 return generic_permission(inode, mask, reiserfs_check_acl); 965 #endif 966 return generic_permission(inode, mask, NULL); 967 } 968 969 /* This will catch lookups from the fs root to .reiserfs_priv */ 970 static int 971 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 972 { 973 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 974 if (container_of(q1, struct dentry, d_name) == priv_root) 975 return -ENOENT; 976 if (q1->len == name->len && 977 !memcmp(q1->name, name->name, name->len)) 978 return 0; 979 return 1; 980 } 981 982 static const struct dentry_operations xattr_lookup_poison_ops = { 983 .d_compare = xattr_lookup_poison, 984 }; 985 986 int reiserfs_lookup_privroot(struct super_block *s) 987 { 988 struct dentry *dentry; 989 int err = 0; 990 991 /* If we don't have the privroot located yet - go find it */ 992 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 993 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 994 strlen(PRIVROOT_NAME)); 995 if (!IS_ERR(dentry)) { 996 REISERFS_SB(s)->priv_root = dentry; 997 if (!reiserfs_expose_privroot(s)) 998 s->s_root->d_op = &xattr_lookup_poison_ops; 999 if (dentry->d_inode) 1000 dentry->d_inode->i_flags |= S_PRIVATE; 1001 } else 1002 err = PTR_ERR(dentry); 1003 mutex_unlock(&s->s_root->d_inode->i_mutex); 1004 1005 return err; 1006 } 1007 1008 /* We need to take a copy of the mount flags since things like 1009 * MS_RDONLY don't get set until *after* we're called. 1010 * mount_flags != mount_options */ 1011 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1012 { 1013 int err = 0; 1014 struct dentry *privroot = REISERFS_SB(s)->priv_root; 1015 1016 err = xattr_mount_check(s); 1017 if (err) 1018 goto error; 1019 1020 if (!privroot->d_inode && !(mount_flags & MS_RDONLY)) { 1021 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 1022 err = create_privroot(REISERFS_SB(s)->priv_root); 1023 mutex_unlock(&s->s_root->d_inode->i_mutex); 1024 } 1025 1026 if (privroot->d_inode) { 1027 s->s_xattr = reiserfs_xattr_handlers; 1028 reiserfs_mutex_lock_safe(&privroot->d_inode->i_mutex, s); 1029 if (!REISERFS_SB(s)->xattr_root) { 1030 struct dentry *dentry; 1031 dentry = lookup_one_len(XAROOT_NAME, privroot, 1032 strlen(XAROOT_NAME)); 1033 if (!IS_ERR(dentry)) 1034 REISERFS_SB(s)->xattr_root = dentry; 1035 else 1036 err = PTR_ERR(dentry); 1037 } 1038 mutex_unlock(&privroot->d_inode->i_mutex); 1039 } 1040 1041 error: 1042 if (err) { 1043 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1044 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1045 } 1046 1047 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1048 if (reiserfs_posixacl(s)) 1049 s->s_flags |= MS_POSIXACL; 1050 else 1051 s->s_flags &= ~MS_POSIXACL; 1052 1053 return err; 1054 } 1055