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/gfp.h> 42 #include <linux/fs.h> 43 #include <linux/file.h> 44 #include <linux/pagemap.h> 45 #include <linux/xattr.h> 46 #include <linux/reiserfs_xattr.h> 47 #include <linux/reiserfs_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, 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 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 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 #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE) 114 115 static struct dentry *open_xa_root(struct super_block *sb, int flags) 116 { 117 struct dentry *privroot = REISERFS_SB(sb)->priv_root; 118 struct dentry *xaroot; 119 if (!privroot->d_inode) 120 return ERR_PTR(-ENODATA); 121 122 mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR); 123 124 xaroot = dget(REISERFS_SB(sb)->xattr_root); 125 if (!xaroot) 126 xaroot = ERR_PTR(-ENODATA); 127 else if (!xaroot->d_inode) { 128 int err = -ENODATA; 129 if (xattr_may_create(flags)) 130 err = xattr_mkdir(privroot->d_inode, xaroot, 0700); 131 if (err) { 132 dput(xaroot); 133 xaroot = ERR_PTR(err); 134 } 135 } 136 137 mutex_unlock(&privroot->d_inode->i_mutex); 138 return xaroot; 139 } 140 141 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 142 { 143 struct dentry *xaroot, *xadir; 144 char namebuf[17]; 145 146 xaroot = open_xa_root(inode->i_sb, flags); 147 if (IS_ERR(xaroot)) 148 return xaroot; 149 150 snprintf(namebuf, sizeof(namebuf), "%X.%X", 151 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 152 inode->i_generation); 153 154 mutex_lock_nested(&xaroot->d_inode->i_mutex, I_MUTEX_XATTR); 155 156 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); 157 if (!IS_ERR(xadir) && !xadir->d_inode) { 158 int err = -ENODATA; 159 if (xattr_may_create(flags)) 160 err = xattr_mkdir(xaroot->d_inode, xadir, 0700); 161 if (err) { 162 dput(xadir); 163 xadir = ERR_PTR(err); 164 } 165 } 166 167 mutex_unlock(&xaroot->d_inode->i_mutex); 168 dput(xaroot); 169 return xadir; 170 } 171 172 /* The following are side effects of other operations that aren't explicitly 173 * modifying extended attributes. This includes operations such as permissions 174 * or ownership changes, object deletions, etc. */ 175 struct reiserfs_dentry_buf { 176 struct dentry *xadir; 177 int count; 178 struct dentry *dentries[8]; 179 }; 180 181 static int 182 fill_with_dentries(void *buf, const char *name, int namelen, loff_t offset, 183 u64 ino, unsigned int d_type) 184 { 185 struct reiserfs_dentry_buf *dbuf = buf; 186 struct dentry *dentry; 187 WARN_ON_ONCE(!mutex_is_locked(&dbuf->xadir->d_inode->i_mutex)); 188 189 if (dbuf->count == ARRAY_SIZE(dbuf->dentries)) 190 return -ENOSPC; 191 192 if (name[0] == '.' && (name[1] == '\0' || 193 (name[1] == '.' && name[2] == '\0'))) 194 return 0; 195 196 dentry = lookup_one_len(name, dbuf->xadir, namelen); 197 if (IS_ERR(dentry)) { 198 return PTR_ERR(dentry); 199 } else if (!dentry->d_inode) { 200 /* A directory entry exists, but no file? */ 201 reiserfs_error(dentry->d_sb, "xattr-20003", 202 "Corrupted directory: xattr %s listed but " 203 "not found for file %s.\n", 204 dentry->d_name.name, dbuf->xadir->d_name.name); 205 dput(dentry); 206 return -EIO; 207 } 208 209 dbuf->dentries[dbuf->count++] = dentry; 210 return 0; 211 } 212 213 static void 214 cleanup_dentry_buf(struct reiserfs_dentry_buf *buf) 215 { 216 int i; 217 for (i = 0; i < buf->count; i++) 218 if (buf->dentries[i]) 219 dput(buf->dentries[i]); 220 } 221 222 static int reiserfs_for_each_xattr(struct inode *inode, 223 int (*action)(struct dentry *, void *), 224 void *data) 225 { 226 struct dentry *dir; 227 int i, err = 0; 228 loff_t pos = 0; 229 struct reiserfs_dentry_buf buf = { 230 .count = 0, 231 }; 232 233 /* Skip out, an xattr has no xattrs associated with it */ 234 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 235 return 0; 236 237 reiserfs_write_unlock(inode->i_sb); 238 dir = open_xa_dir(inode, XATTR_REPLACE); 239 if (IS_ERR(dir)) { 240 err = PTR_ERR(dir); 241 reiserfs_write_lock(inode->i_sb); 242 goto out; 243 } else if (!dir->d_inode) { 244 err = 0; 245 reiserfs_write_lock(inode->i_sb); 246 goto out_dir; 247 } 248 249 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 250 251 reiserfs_write_lock(inode->i_sb); 252 253 buf.xadir = dir; 254 err = reiserfs_readdir_dentry(dir, &buf, fill_with_dentries, &pos); 255 while ((err == 0 || err == -ENOSPC) && buf.count) { 256 err = 0; 257 258 for (i = 0; i < buf.count && buf.dentries[i]; i++) { 259 int lerr = 0; 260 struct dentry *dentry = buf.dentries[i]; 261 262 if (err == 0 && !S_ISDIR(dentry->d_inode->i_mode)) 263 lerr = action(dentry, data); 264 265 dput(dentry); 266 buf.dentries[i] = NULL; 267 err = lerr ?: err; 268 } 269 buf.count = 0; 270 if (!err) 271 err = reiserfs_readdir_dentry(dir, &buf, 272 fill_with_dentries, &pos); 273 } 274 mutex_unlock(&dir->d_inode->i_mutex); 275 276 /* Clean up after a failed readdir */ 277 cleanup_dentry_buf(&buf); 278 279 if (!err) { 280 /* We start a transaction here to avoid a ABBA situation 281 * between the xattr root's i_mutex and the journal lock. 282 * This doesn't incur much additional overhead since the 283 * new transaction will just nest inside the 284 * outer transaction. */ 285 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 286 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); 287 struct reiserfs_transaction_handle th; 288 err = journal_begin(&th, inode->i_sb, blocks); 289 if (!err) { 290 int jerror; 291 reiserfs_mutex_lock_nested_safe( 292 &dir->d_parent->d_inode->i_mutex, 293 I_MUTEX_XATTR, inode->i_sb); 294 err = action(dir, data); 295 jerror = journal_end(&th, inode->i_sb, blocks); 296 mutex_unlock(&dir->d_parent->d_inode->i_mutex); 297 err = jerror ?: err; 298 } 299 } 300 out_dir: 301 dput(dir); 302 out: 303 /* -ENODATA isn't an error */ 304 if (err == -ENODATA) 305 err = 0; 306 return err; 307 } 308 309 static int delete_one_xattr(struct dentry *dentry, void *data) 310 { 311 struct inode *dir = dentry->d_parent->d_inode; 312 313 /* This is the xattr dir, handle specially. */ 314 if (S_ISDIR(dentry->d_inode->i_mode)) 315 return xattr_rmdir(dir, dentry); 316 317 return xattr_unlink(dir, dentry); 318 } 319 320 static int chown_one_xattr(struct dentry *dentry, void *data) 321 { 322 struct iattr *attrs = data; 323 return reiserfs_setattr(dentry, attrs); 324 } 325 326 /* No i_mutex, but the inode is unconnected. */ 327 int reiserfs_delete_xattrs(struct inode *inode) 328 { 329 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL); 330 if (err) 331 reiserfs_warning(inode->i_sb, "jdm-20004", 332 "Couldn't delete all xattrs (%d)\n", err); 333 return err; 334 } 335 336 /* inode->i_mutex: down */ 337 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 338 { 339 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs); 340 if (err) 341 reiserfs_warning(inode->i_sb, "jdm-20007", 342 "Couldn't chown all xattrs (%d)\n", err); 343 return err; 344 } 345 346 #ifdef CONFIG_REISERFS_FS_XATTR 347 /* Returns a dentry corresponding to a specific extended attribute file 348 * for the inode. If flags allow, the file is created. Otherwise, a 349 * valid or negative dentry, or an error is returned. */ 350 static struct dentry *xattr_lookup(struct inode *inode, const char *name, 351 int flags) 352 { 353 struct dentry *xadir, *xafile; 354 int err = 0; 355 356 xadir = open_xa_dir(inode, flags); 357 if (IS_ERR(xadir)) 358 return ERR_CAST(xadir); 359 360 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 361 xafile = lookup_one_len(name, xadir, strlen(name)); 362 if (IS_ERR(xafile)) { 363 err = PTR_ERR(xafile); 364 goto out; 365 } 366 367 if (xafile->d_inode && (flags & XATTR_CREATE)) 368 err = -EEXIST; 369 370 if (!xafile->d_inode) { 371 err = -ENODATA; 372 if (xattr_may_create(flags)) 373 err = xattr_create(xadir->d_inode, xafile, 374 0700|S_IFREG); 375 } 376 377 if (err) 378 dput(xafile); 379 out: 380 mutex_unlock(&xadir->d_inode->i_mutex); 381 dput(xadir); 382 if (err) 383 return ERR_PTR(err); 384 return xafile; 385 } 386 387 /* Internal operations on file data */ 388 static inline void reiserfs_put_page(struct page *page) 389 { 390 kunmap(page); 391 page_cache_release(page); 392 } 393 394 static struct page *reiserfs_get_page(struct inode *dir, size_t n) 395 { 396 struct address_space *mapping = dir->i_mapping; 397 struct page *page; 398 /* We can deadlock if we try to free dentries, 399 and an unlink/rmdir has just occured - GFP_NOFS avoids this */ 400 mapping_set_gfp_mask(mapping, GFP_NOFS); 401 page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); 402 if (!IS_ERR(page)) { 403 kmap(page); 404 if (PageError(page)) 405 goto fail; 406 } 407 return page; 408 409 fail: 410 reiserfs_put_page(page); 411 return ERR_PTR(-EIO); 412 } 413 414 static inline __u32 xattr_hash(const char *msg, int len) 415 { 416 return csum_partial(msg, len, 0); 417 } 418 419 int reiserfs_commit_write(struct file *f, struct page *page, 420 unsigned from, unsigned to); 421 int reiserfs_prepare_write(struct file *f, struct page *page, 422 unsigned from, unsigned to); 423 424 static void update_ctime(struct inode *inode) 425 { 426 struct timespec now = current_fs_time(inode->i_sb); 427 if (hlist_unhashed(&inode->i_hash) || !inode->i_nlink || 428 timespec_equal(&inode->i_ctime, &now)) 429 return; 430 431 inode->i_ctime = CURRENT_TIME_SEC; 432 mark_inode_dirty(inode); 433 } 434 435 static int lookup_and_delete_xattr(struct inode *inode, const char *name) 436 { 437 int err = 0; 438 struct dentry *dentry, *xadir; 439 440 xadir = open_xa_dir(inode, XATTR_REPLACE); 441 if (IS_ERR(xadir)) 442 return PTR_ERR(xadir); 443 444 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 445 dentry = lookup_one_len(name, xadir, strlen(name)); 446 if (IS_ERR(dentry)) { 447 err = PTR_ERR(dentry); 448 goto out_dput; 449 } 450 451 if (dentry->d_inode) { 452 reiserfs_write_lock(inode->i_sb); 453 err = xattr_unlink(xadir->d_inode, dentry); 454 reiserfs_write_unlock(inode->i_sb); 455 update_ctime(inode); 456 } 457 458 dput(dentry); 459 out_dput: 460 mutex_unlock(&xadir->d_inode->i_mutex); 461 dput(xadir); 462 return err; 463 } 464 465 466 /* Generic extended attribute operations that can be used by xa plugins */ 467 468 /* 469 * inode->i_mutex: down 470 */ 471 int 472 reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th, 473 struct inode *inode, const char *name, 474 const void *buffer, size_t buffer_size, int flags) 475 { 476 int err = 0; 477 struct dentry *dentry; 478 struct page *page; 479 char *data; 480 size_t file_pos = 0; 481 size_t buffer_pos = 0; 482 size_t new_size; 483 __u32 xahash = 0; 484 485 if (get_inode_sd_version(inode) == STAT_DATA_V1) 486 return -EOPNOTSUPP; 487 488 reiserfs_write_unlock(inode->i_sb); 489 490 if (!buffer) { 491 err = lookup_and_delete_xattr(inode, name); 492 reiserfs_write_lock(inode->i_sb); 493 return err; 494 } 495 496 dentry = xattr_lookup(inode, name, flags); 497 if (IS_ERR(dentry)) { 498 reiserfs_write_lock(inode->i_sb); 499 return PTR_ERR(dentry); 500 } 501 502 down_write(&REISERFS_I(inode)->i_xattr_sem); 503 504 reiserfs_write_lock(inode->i_sb); 505 506 xahash = xattr_hash(buffer, buffer_size); 507 while (buffer_pos < buffer_size || buffer_pos == 0) { 508 size_t chunk; 509 size_t skip = 0; 510 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 511 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 512 chunk = PAGE_CACHE_SIZE; 513 else 514 chunk = buffer_size - buffer_pos; 515 516 page = reiserfs_get_page(dentry->d_inode, file_pos); 517 if (IS_ERR(page)) { 518 err = PTR_ERR(page); 519 goto out_unlock; 520 } 521 522 lock_page(page); 523 data = page_address(page); 524 525 if (file_pos == 0) { 526 struct reiserfs_xattr_header *rxh; 527 skip = file_pos = sizeof(struct reiserfs_xattr_header); 528 if (chunk + skip > PAGE_CACHE_SIZE) 529 chunk = PAGE_CACHE_SIZE - skip; 530 rxh = (struct reiserfs_xattr_header *)data; 531 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 532 rxh->h_hash = cpu_to_le32(xahash); 533 } 534 535 err = reiserfs_prepare_write(NULL, page, page_offset, 536 page_offset + chunk + skip); 537 if (!err) { 538 if (buffer) 539 memcpy(data + skip, buffer + buffer_pos, chunk); 540 err = reiserfs_commit_write(NULL, page, page_offset, 541 page_offset + chunk + 542 skip); 543 } 544 unlock_page(page); 545 reiserfs_put_page(page); 546 buffer_pos += chunk; 547 file_pos += chunk; 548 skip = 0; 549 if (err || buffer_size == 0 || !buffer) 550 break; 551 } 552 553 new_size = buffer_size + sizeof(struct reiserfs_xattr_header); 554 if (!err && new_size < i_size_read(dentry->d_inode)) { 555 struct iattr newattrs = { 556 .ia_ctime = current_fs_time(inode->i_sb), 557 .ia_size = new_size, 558 .ia_valid = ATTR_SIZE | ATTR_CTIME, 559 }; 560 561 reiserfs_write_unlock(inode->i_sb); 562 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 563 down_write(&dentry->d_inode->i_alloc_sem); 564 reiserfs_write_lock(inode->i_sb); 565 566 err = reiserfs_setattr(dentry, &newattrs); 567 up_write(&dentry->d_inode->i_alloc_sem); 568 mutex_unlock(&dentry->d_inode->i_mutex); 569 } else 570 update_ctime(inode); 571 out_unlock: 572 up_write(&REISERFS_I(inode)->i_xattr_sem); 573 dput(dentry); 574 return err; 575 } 576 577 /* We need to start a transaction to maintain lock ordering */ 578 int reiserfs_xattr_set(struct inode *inode, const char *name, 579 const void *buffer, size_t buffer_size, int flags) 580 { 581 582 struct reiserfs_transaction_handle th; 583 int error, error2; 584 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); 585 586 if (!(flags & XATTR_REPLACE)) 587 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); 588 589 reiserfs_write_lock(inode->i_sb); 590 error = journal_begin(&th, inode->i_sb, jbegin_count); 591 if (error) { 592 reiserfs_write_unlock(inode->i_sb); 593 return error; 594 } 595 596 error = reiserfs_xattr_set_handle(&th, inode, name, 597 buffer, buffer_size, flags); 598 599 error2 = journal_end(&th, inode->i_sb, jbegin_count); 600 if (error == 0) 601 error = error2; 602 reiserfs_write_unlock(inode->i_sb); 603 604 return error; 605 } 606 607 /* 608 * inode->i_mutex: down 609 */ 610 int 611 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, 612 size_t buffer_size) 613 { 614 ssize_t err = 0; 615 struct dentry *dentry; 616 size_t isize; 617 size_t file_pos = 0; 618 size_t buffer_pos = 0; 619 struct page *page; 620 __u32 hash = 0; 621 622 if (name == NULL) 623 return -EINVAL; 624 625 /* We can't have xattrs attached to v1 items since they don't have 626 * generation numbers */ 627 if (get_inode_sd_version(inode) == STAT_DATA_V1) 628 return -EOPNOTSUPP; 629 630 dentry = xattr_lookup(inode, name, XATTR_REPLACE); 631 if (IS_ERR(dentry)) { 632 err = PTR_ERR(dentry); 633 goto out; 634 } 635 636 down_read(&REISERFS_I(inode)->i_xattr_sem); 637 638 isize = i_size_read(dentry->d_inode); 639 640 /* Just return the size needed */ 641 if (buffer == NULL) { 642 err = isize - sizeof(struct reiserfs_xattr_header); 643 goto out_unlock; 644 } 645 646 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 647 err = -ERANGE; 648 goto out_unlock; 649 } 650 651 while (file_pos < isize) { 652 size_t chunk; 653 char *data; 654 size_t skip = 0; 655 if (isize - file_pos > PAGE_CACHE_SIZE) 656 chunk = PAGE_CACHE_SIZE; 657 else 658 chunk = isize - file_pos; 659 660 page = reiserfs_get_page(dentry->d_inode, file_pos); 661 if (IS_ERR(page)) { 662 err = PTR_ERR(page); 663 goto out_unlock; 664 } 665 666 lock_page(page); 667 data = page_address(page); 668 if (file_pos == 0) { 669 struct reiserfs_xattr_header *rxh = 670 (struct reiserfs_xattr_header *)data; 671 skip = file_pos = sizeof(struct reiserfs_xattr_header); 672 chunk -= skip; 673 /* Magic doesn't match up.. */ 674 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 675 unlock_page(page); 676 reiserfs_put_page(page); 677 reiserfs_warning(inode->i_sb, "jdm-20001", 678 "Invalid magic for xattr (%s) " 679 "associated with %k", name, 680 INODE_PKEY(inode)); 681 err = -EIO; 682 goto out_unlock; 683 } 684 hash = le32_to_cpu(rxh->h_hash); 685 } 686 memcpy(buffer + buffer_pos, data + skip, chunk); 687 unlock_page(page); 688 reiserfs_put_page(page); 689 file_pos += chunk; 690 buffer_pos += chunk; 691 skip = 0; 692 } 693 err = isize - sizeof(struct reiserfs_xattr_header); 694 695 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 696 hash) { 697 reiserfs_warning(inode->i_sb, "jdm-20002", 698 "Invalid hash for xattr (%s) associated " 699 "with %k", name, INODE_PKEY(inode)); 700 err = -EIO; 701 } 702 703 out_unlock: 704 up_read(&REISERFS_I(inode)->i_xattr_sem); 705 dput(dentry); 706 707 out: 708 return err; 709 } 710 711 /* 712 * In order to implement different sets of xattr operations for each xattr 713 * prefix with the generic xattr API, a filesystem should create a 714 * null-terminated array of struct xattr_handler (one for each prefix) and 715 * hang a pointer to it off of the s_xattr field of the superblock. 716 * 717 * The generic_fooxattr() functions will use this list to dispatch xattr 718 * operations to the correct xattr_handler. 719 */ 720 #define for_each_xattr_handler(handlers, handler) \ 721 for ((handler) = *(handlers)++; \ 722 (handler) != NULL; \ 723 (handler) = *(handlers)++) 724 725 /* This is the implementation for the xattr plugin infrastructure */ 726 static inline const struct xattr_handler * 727 find_xattr_handler_prefix(const struct xattr_handler **handlers, 728 const char *name) 729 { 730 const struct xattr_handler *xah; 731 732 if (!handlers) 733 return NULL; 734 735 for_each_xattr_handler(handlers, xah) { 736 if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0) 737 break; 738 } 739 740 return xah; 741 } 742 743 744 /* 745 * Inode operation getxattr() 746 */ 747 ssize_t 748 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 749 size_t size) 750 { 751 const struct xattr_handler *handler; 752 753 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 754 755 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 756 return -EOPNOTSUPP; 757 758 return handler->get(dentry, name, buffer, size, handler->flags); 759 } 760 761 /* 762 * Inode operation setxattr() 763 * 764 * dentry->d_inode->i_mutex down 765 */ 766 int 767 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 768 size_t size, int flags) 769 { 770 const struct xattr_handler *handler; 771 772 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 773 774 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 775 return -EOPNOTSUPP; 776 777 return handler->set(dentry, name, value, size, flags, handler->flags); 778 } 779 780 /* 781 * Inode operation removexattr() 782 * 783 * dentry->d_inode->i_mutex down 784 */ 785 int reiserfs_removexattr(struct dentry *dentry, const char *name) 786 { 787 const struct xattr_handler *handler; 788 handler = find_xattr_handler_prefix(dentry->d_sb->s_xattr, name); 789 790 if (!handler || get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 791 return -EOPNOTSUPP; 792 793 return handler->set(dentry, name, NULL, 0, XATTR_REPLACE, handler->flags); 794 } 795 796 struct listxattr_buf { 797 size_t size; 798 size_t pos; 799 char *buf; 800 struct dentry *dentry; 801 }; 802 803 static int listxattr_filler(void *buf, const char *name, int namelen, 804 loff_t offset, u64 ino, unsigned int d_type) 805 { 806 struct listxattr_buf *b = (struct listxattr_buf *)buf; 807 size_t size; 808 if (name[0] != '.' || 809 (namelen != 1 && (name[1] != '.' || namelen != 2))) { 810 const struct xattr_handler *handler; 811 handler = find_xattr_handler_prefix(b->dentry->d_sb->s_xattr, 812 name); 813 if (!handler) /* Unsupported xattr name */ 814 return 0; 815 if (b->buf) { 816 size = handler->list(b->dentry, b->buf + b->pos, 817 b->size, name, namelen, 818 handler->flags); 819 if (size > b->size) 820 return -ERANGE; 821 } else { 822 size = handler->list(b->dentry, NULL, 0, name, 823 namelen, handler->flags); 824 } 825 826 b->pos += size; 827 } 828 return 0; 829 } 830 831 /* 832 * Inode operation listxattr() 833 * 834 * We totally ignore the generic listxattr here because it would be stupid 835 * not to. Since the xattrs are organized in a directory, we can just 836 * readdir to find them. 837 */ 838 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 839 { 840 struct dentry *dir; 841 int err = 0; 842 loff_t pos = 0; 843 struct listxattr_buf buf = { 844 .dentry = dentry, 845 .buf = buffer, 846 .size = buffer ? size : 0, 847 }; 848 849 if (!dentry->d_inode) 850 return -EINVAL; 851 852 if (!dentry->d_sb->s_xattr || 853 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 854 return -EOPNOTSUPP; 855 856 dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); 857 if (IS_ERR(dir)) { 858 err = PTR_ERR(dir); 859 if (err == -ENODATA) 860 err = 0; /* Not an error if there aren't any xattrs */ 861 goto out; 862 } 863 864 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 865 err = reiserfs_readdir_dentry(dir, &buf, listxattr_filler, &pos); 866 mutex_unlock(&dir->d_inode->i_mutex); 867 868 if (!err) 869 err = buf.pos; 870 871 dput(dir); 872 out: 873 return err; 874 } 875 876 static int reiserfs_check_acl(struct inode *inode, int mask) 877 { 878 struct posix_acl *acl; 879 int error = -EAGAIN; /* do regular unix permission checks by default */ 880 881 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 882 883 if (acl) { 884 if (!IS_ERR(acl)) { 885 error = posix_acl_permission(inode, acl, mask); 886 posix_acl_release(acl); 887 } else if (PTR_ERR(acl) != -ENODATA) 888 error = PTR_ERR(acl); 889 } 890 891 return error; 892 } 893 894 static int create_privroot(struct dentry *dentry) 895 { 896 int err; 897 struct inode *inode = dentry->d_parent->d_inode; 898 WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex)); 899 900 err = xattr_mkdir(inode, dentry, 0700); 901 if (err || !dentry->d_inode) { 902 reiserfs_warning(dentry->d_sb, "jdm-20006", 903 "xattrs/ACLs enabled and couldn't " 904 "find/create .reiserfs_priv. " 905 "Failing mount."); 906 return -EOPNOTSUPP; 907 } 908 909 dentry->d_inode->i_flags |= S_PRIVATE; 910 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 911 "storage.\n", PRIVROOT_NAME); 912 913 return 0; 914 } 915 916 #else 917 int __init reiserfs_xattr_register_handlers(void) { return 0; } 918 void reiserfs_xattr_unregister_handlers(void) {} 919 static int create_privroot(struct dentry *dentry) { return 0; } 920 #endif 921 922 /* Actual operations that are exported to VFS-land */ 923 const struct xattr_handler *reiserfs_xattr_handlers[] = { 924 #ifdef CONFIG_REISERFS_FS_XATTR 925 &reiserfs_xattr_user_handler, 926 &reiserfs_xattr_trusted_handler, 927 #endif 928 #ifdef CONFIG_REISERFS_FS_SECURITY 929 &reiserfs_xattr_security_handler, 930 #endif 931 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 932 &reiserfs_posix_acl_access_handler, 933 &reiserfs_posix_acl_default_handler, 934 #endif 935 NULL 936 }; 937 938 static int xattr_mount_check(struct super_block *s) 939 { 940 /* We need generation numbers to ensure that the oid mapping is correct 941 * v3.5 filesystems don't have them. */ 942 if (old_format_only(s)) { 943 if (reiserfs_xattrs_optional(s)) { 944 /* Old format filesystem, but optional xattrs have 945 * been enabled. Error out. */ 946 reiserfs_warning(s, "jdm-2005", 947 "xattrs/ACLs not supported " 948 "on pre-v3.6 format filesystems. " 949 "Failing mount."); 950 return -EOPNOTSUPP; 951 } 952 } 953 954 return 0; 955 } 956 957 int reiserfs_permission(struct inode *inode, int mask) 958 { 959 /* 960 * We don't do permission checks on the internal objects. 961 * Permissions are determined by the "owning" object. 962 */ 963 if (IS_PRIVATE(inode)) 964 return 0; 965 966 #ifdef CONFIG_REISERFS_FS_XATTR 967 /* 968 * Stat data v1 doesn't support ACLs. 969 */ 970 if (get_inode_sd_version(inode) != STAT_DATA_V1) 971 return generic_permission(inode, mask, reiserfs_check_acl); 972 #endif 973 return generic_permission(inode, mask, NULL); 974 } 975 976 static int xattr_hide_revalidate(struct dentry *dentry, struct nameidata *nd) 977 { 978 return -EPERM; 979 } 980 981 static const struct dentry_operations xattr_lookup_poison_ops = { 982 .d_revalidate = xattr_hide_revalidate, 983 }; 984 985 int reiserfs_lookup_privroot(struct super_block *s) 986 { 987 struct dentry *dentry; 988 int err = 0; 989 990 /* If we don't have the privroot located yet - go find it */ 991 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 992 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 993 strlen(PRIVROOT_NAME)); 994 if (!IS_ERR(dentry)) { 995 REISERFS_SB(s)->priv_root = dentry; 996 dentry->d_op = &xattr_lookup_poison_ops; 997 if (dentry->d_inode) 998 dentry->d_inode->i_flags |= S_PRIVATE; 999 } else 1000 err = PTR_ERR(dentry); 1001 mutex_unlock(&s->s_root->d_inode->i_mutex); 1002 1003 return err; 1004 } 1005 1006 /* We need to take a copy of the mount flags since things like 1007 * MS_RDONLY don't get set until *after* we're called. 1008 * mount_flags != mount_options */ 1009 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1010 { 1011 int err = 0; 1012 struct dentry *privroot = REISERFS_SB(s)->priv_root; 1013 1014 err = xattr_mount_check(s); 1015 if (err) 1016 goto error; 1017 1018 if (!privroot->d_inode && !(mount_flags & MS_RDONLY)) { 1019 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 1020 err = create_privroot(REISERFS_SB(s)->priv_root); 1021 mutex_unlock(&s->s_root->d_inode->i_mutex); 1022 } 1023 1024 if (privroot->d_inode) { 1025 s->s_xattr = reiserfs_xattr_handlers; 1026 reiserfs_mutex_lock_safe(&privroot->d_inode->i_mutex, s); 1027 if (!REISERFS_SB(s)->xattr_root) { 1028 struct dentry *dentry; 1029 dentry = lookup_one_len(XAROOT_NAME, privroot, 1030 strlen(XAROOT_NAME)); 1031 if (!IS_ERR(dentry)) 1032 REISERFS_SB(s)->xattr_root = dentry; 1033 else 1034 err = PTR_ERR(dentry); 1035 } 1036 mutex_unlock(&privroot->d_inode->i_mutex); 1037 } 1038 1039 error: 1040 if (err) { 1041 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1042 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1043 } 1044 1045 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1046 if (reiserfs_posixacl(s)) 1047 s->s_flags |= MS_POSIXACL; 1048 else 1049 s->s_flags &= ~MS_POSIXACL; 1050 1051 return err; 1052 } 1053