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 52 #define PRIVROOT_NAME ".reiserfs_priv" 53 #define XAROOT_NAME "xattrs" 54 55 56 /* Helpers for inode ops. We do this so that we don't have all the VFS 57 * overhead and also for proper i_mutex annotation. 58 * dir->i_mutex must be held for all of them. */ 59 #ifdef CONFIG_REISERFS_FS_XATTR 60 static int xattr_create(struct inode *dir, struct dentry *dentry, int mode) 61 { 62 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 63 vfs_dq_init(dir); 64 return dir->i_op->create(dir, dentry, mode, NULL); 65 } 66 #endif 67 68 static int xattr_mkdir(struct inode *dir, struct dentry *dentry, int mode) 69 { 70 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 71 vfs_dq_init(dir); 72 return dir->i_op->mkdir(dir, dentry, mode); 73 } 74 75 /* We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr 76 * mutation ops aren't called during rename or splace, which are the 77 * only other users of I_MUTEX_CHILD. It violates the ordering, but that's 78 * better than allocating another subclass just for this code. */ 79 static int xattr_unlink(struct inode *dir, struct dentry *dentry) 80 { 81 int error; 82 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 83 vfs_dq_init(dir); 84 85 reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex, 86 I_MUTEX_CHILD, dir->i_sb); 87 error = dir->i_op->unlink(dir, dentry); 88 mutex_unlock(&dentry->d_inode->i_mutex); 89 90 if (!error) 91 d_delete(dentry); 92 return error; 93 } 94 95 static int xattr_rmdir(struct inode *dir, struct dentry *dentry) 96 { 97 int error; 98 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 99 vfs_dq_init(dir); 100 101 reiserfs_mutex_lock_nested_safe(&dentry->d_inode->i_mutex, 102 I_MUTEX_CHILD, dir->i_sb); 103 dentry_unhash(dentry); 104 error = dir->i_op->rmdir(dir, dentry); 105 if (!error) 106 dentry->d_inode->i_flags |= S_DEAD; 107 mutex_unlock(&dentry->d_inode->i_mutex); 108 if (!error) 109 d_delete(dentry); 110 dput(dentry); 111 112 return error; 113 } 114 115 #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE) 116 117 static struct dentry *open_xa_root(struct super_block *sb, int flags) 118 { 119 struct dentry *privroot = REISERFS_SB(sb)->priv_root; 120 struct dentry *xaroot; 121 if (!privroot->d_inode) 122 return ERR_PTR(-ENODATA); 123 124 mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR); 125 126 xaroot = dget(REISERFS_SB(sb)->xattr_root); 127 if (!xaroot) 128 xaroot = ERR_PTR(-ENODATA); 129 else if (!xaroot->d_inode) { 130 int err = -ENODATA; 131 if (xattr_may_create(flags)) 132 err = xattr_mkdir(privroot->d_inode, xaroot, 0700); 133 if (err) { 134 dput(xaroot); 135 xaroot = ERR_PTR(err); 136 } 137 } 138 139 mutex_unlock(&privroot->d_inode->i_mutex); 140 return xaroot; 141 } 142 143 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 144 { 145 struct dentry *xaroot, *xadir; 146 char namebuf[17]; 147 148 xaroot = open_xa_root(inode->i_sb, flags); 149 if (IS_ERR(xaroot)) 150 return xaroot; 151 152 snprintf(namebuf, sizeof(namebuf), "%X.%X", 153 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 154 inode->i_generation); 155 156 mutex_lock_nested(&xaroot->d_inode->i_mutex, I_MUTEX_XATTR); 157 158 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); 159 if (!IS_ERR(xadir) && !xadir->d_inode) { 160 int err = -ENODATA; 161 if (xattr_may_create(flags)) 162 err = xattr_mkdir(xaroot->d_inode, xadir, 0700); 163 if (err) { 164 dput(xadir); 165 xadir = ERR_PTR(err); 166 } 167 } 168 169 mutex_unlock(&xaroot->d_inode->i_mutex); 170 dput(xaroot); 171 return xadir; 172 } 173 174 /* The following are side effects of other operations that aren't explicitly 175 * modifying extended attributes. This includes operations such as permissions 176 * or ownership changes, object deletions, etc. */ 177 struct reiserfs_dentry_buf { 178 struct dentry *xadir; 179 int count; 180 struct dentry *dentries[8]; 181 }; 182 183 static int 184 fill_with_dentries(void *buf, const char *name, int namelen, loff_t offset, 185 u64 ino, unsigned int d_type) 186 { 187 struct reiserfs_dentry_buf *dbuf = buf; 188 struct dentry *dentry; 189 WARN_ON_ONCE(!mutex_is_locked(&dbuf->xadir->d_inode->i_mutex)); 190 191 if (dbuf->count == ARRAY_SIZE(dbuf->dentries)) 192 return -ENOSPC; 193 194 if (name[0] == '.' && (name[1] == '\0' || 195 (name[1] == '.' && name[2] == '\0'))) 196 return 0; 197 198 dentry = lookup_one_len(name, dbuf->xadir, namelen); 199 if (IS_ERR(dentry)) { 200 return PTR_ERR(dentry); 201 } else if (!dentry->d_inode) { 202 /* A directory entry exists, but no file? */ 203 reiserfs_error(dentry->d_sb, "xattr-20003", 204 "Corrupted directory: xattr %s listed but " 205 "not found for file %s.\n", 206 dentry->d_name.name, dbuf->xadir->d_name.name); 207 dput(dentry); 208 return -EIO; 209 } 210 211 dbuf->dentries[dbuf->count++] = dentry; 212 return 0; 213 } 214 215 static void 216 cleanup_dentry_buf(struct reiserfs_dentry_buf *buf) 217 { 218 int i; 219 for (i = 0; i < buf->count; i++) 220 if (buf->dentries[i]) 221 dput(buf->dentries[i]); 222 } 223 224 static int reiserfs_for_each_xattr(struct inode *inode, 225 int (*action)(struct dentry *, void *), 226 void *data) 227 { 228 struct dentry *dir; 229 int i, err = 0; 230 loff_t pos = 0; 231 struct reiserfs_dentry_buf buf = { 232 .count = 0, 233 }; 234 235 /* Skip out, an xattr has no xattrs associated with it */ 236 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 237 return 0; 238 239 reiserfs_write_unlock(inode->i_sb); 240 dir = open_xa_dir(inode, XATTR_REPLACE); 241 if (IS_ERR(dir)) { 242 err = PTR_ERR(dir); 243 reiserfs_write_lock(inode->i_sb); 244 goto out; 245 } else if (!dir->d_inode) { 246 err = 0; 247 reiserfs_write_lock(inode->i_sb); 248 goto out_dir; 249 } 250 251 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 252 253 reiserfs_write_lock(inode->i_sb); 254 255 buf.xadir = dir; 256 err = reiserfs_readdir_dentry(dir, &buf, fill_with_dentries, &pos); 257 while ((err == 0 || err == -ENOSPC) && buf.count) { 258 err = 0; 259 260 for (i = 0; i < buf.count && buf.dentries[i]; i++) { 261 int lerr = 0; 262 struct dentry *dentry = buf.dentries[i]; 263 264 if (err == 0 && !S_ISDIR(dentry->d_inode->i_mode)) 265 lerr = action(dentry, data); 266 267 dput(dentry); 268 buf.dentries[i] = NULL; 269 err = lerr ?: err; 270 } 271 buf.count = 0; 272 if (!err) 273 err = reiserfs_readdir_dentry(dir, &buf, 274 fill_with_dentries, &pos); 275 } 276 mutex_unlock(&dir->d_inode->i_mutex); 277 278 /* Clean up after a failed readdir */ 279 cleanup_dentry_buf(&buf); 280 281 if (!err) { 282 /* We start a transaction here to avoid a ABBA situation 283 * between the xattr root's i_mutex and the journal lock. 284 * This doesn't incur much additional overhead since the 285 * new transaction will just nest inside the 286 * outer transaction. */ 287 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 288 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); 289 struct reiserfs_transaction_handle th; 290 err = journal_begin(&th, inode->i_sb, blocks); 291 if (!err) { 292 int jerror; 293 reiserfs_mutex_lock_nested_safe( 294 &dir->d_parent->d_inode->i_mutex, 295 I_MUTEX_XATTR, inode->i_sb); 296 err = action(dir, data); 297 jerror = journal_end(&th, inode->i_sb, blocks); 298 mutex_unlock(&dir->d_parent->d_inode->i_mutex); 299 err = jerror ?: err; 300 } 301 } 302 out_dir: 303 dput(dir); 304 out: 305 /* -ENODATA isn't an error */ 306 if (err == -ENODATA) 307 err = 0; 308 return err; 309 } 310 311 static int delete_one_xattr(struct dentry *dentry, void *data) 312 { 313 struct inode *dir = dentry->d_parent->d_inode; 314 315 /* This is the xattr dir, handle specially. */ 316 if (S_ISDIR(dentry->d_inode->i_mode)) 317 return xattr_rmdir(dir, dentry); 318 319 return xattr_unlink(dir, dentry); 320 } 321 322 static int chown_one_xattr(struct dentry *dentry, void *data) 323 { 324 struct iattr *attrs = data; 325 return reiserfs_setattr(dentry, attrs); 326 } 327 328 /* No i_mutex, but the inode is unconnected. */ 329 int reiserfs_delete_xattrs(struct inode *inode) 330 { 331 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL); 332 if (err) 333 reiserfs_warning(inode->i_sb, "jdm-20004", 334 "Couldn't delete all xattrs (%d)\n", err); 335 return err; 336 } 337 338 /* inode->i_mutex: down */ 339 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 340 { 341 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs); 342 if (err) 343 reiserfs_warning(inode->i_sb, "jdm-20007", 344 "Couldn't chown all xattrs (%d)\n", err); 345 return err; 346 } 347 348 #ifdef CONFIG_REISERFS_FS_XATTR 349 /* Returns a dentry corresponding to a specific extended attribute file 350 * for the inode. If flags allow, the file is created. Otherwise, a 351 * valid or negative dentry, or an error is returned. */ 352 static struct dentry *xattr_lookup(struct inode *inode, const char *name, 353 int flags) 354 { 355 struct dentry *xadir, *xafile; 356 int err = 0; 357 358 xadir = open_xa_dir(inode, flags); 359 if (IS_ERR(xadir)) 360 return ERR_CAST(xadir); 361 362 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 363 xafile = lookup_one_len(name, xadir, strlen(name)); 364 if (IS_ERR(xafile)) { 365 err = PTR_ERR(xafile); 366 goto out; 367 } 368 369 if (xafile->d_inode && (flags & XATTR_CREATE)) 370 err = -EEXIST; 371 372 if (!xafile->d_inode) { 373 err = -ENODATA; 374 if (xattr_may_create(flags)) 375 err = xattr_create(xadir->d_inode, xafile, 376 0700|S_IFREG); 377 } 378 379 if (err) 380 dput(xafile); 381 out: 382 mutex_unlock(&xadir->d_inode->i_mutex); 383 dput(xadir); 384 if (err) 385 return ERR_PTR(err); 386 return xafile; 387 } 388 389 /* Internal operations on file data */ 390 static inline void reiserfs_put_page(struct page *page) 391 { 392 kunmap(page); 393 page_cache_release(page); 394 } 395 396 static struct page *reiserfs_get_page(struct inode *dir, size_t n) 397 { 398 struct address_space *mapping = dir->i_mapping; 399 struct page *page; 400 /* We can deadlock if we try to free dentries, 401 and an unlink/rmdir has just occured - GFP_NOFS avoids this */ 402 mapping_set_gfp_mask(mapping, GFP_NOFS); 403 page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); 404 if (!IS_ERR(page)) { 405 kmap(page); 406 if (PageError(page)) 407 goto fail; 408 } 409 return page; 410 411 fail: 412 reiserfs_put_page(page); 413 return ERR_PTR(-EIO); 414 } 415 416 static inline __u32 xattr_hash(const char *msg, int len) 417 { 418 return csum_partial(msg, len, 0); 419 } 420 421 int reiserfs_commit_write(struct file *f, struct page *page, 422 unsigned from, unsigned to); 423 int reiserfs_prepare_write(struct file *f, struct page *page, 424 unsigned from, unsigned to); 425 426 static void update_ctime(struct inode *inode) 427 { 428 struct timespec now = current_fs_time(inode->i_sb); 429 if (hlist_unhashed(&inode->i_hash) || !inode->i_nlink || 430 timespec_equal(&inode->i_ctime, &now)) 431 return; 432 433 inode->i_ctime = CURRENT_TIME_SEC; 434 mark_inode_dirty(inode); 435 } 436 437 static int lookup_and_delete_xattr(struct inode *inode, const char *name) 438 { 439 int err = 0; 440 struct dentry *dentry, *xadir; 441 442 xadir = open_xa_dir(inode, XATTR_REPLACE); 443 if (IS_ERR(xadir)) 444 return PTR_ERR(xadir); 445 446 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 447 dentry = lookup_one_len(name, xadir, strlen(name)); 448 if (IS_ERR(dentry)) { 449 err = PTR_ERR(dentry); 450 goto out_dput; 451 } 452 453 if (dentry->d_inode) { 454 reiserfs_write_lock(inode->i_sb); 455 err = xattr_unlink(xadir->d_inode, dentry); 456 reiserfs_write_unlock(inode->i_sb); 457 update_ctime(inode); 458 } 459 460 dput(dentry); 461 out_dput: 462 mutex_unlock(&xadir->d_inode->i_mutex); 463 dput(xadir); 464 return err; 465 } 466 467 468 /* Generic extended attribute operations that can be used by xa plugins */ 469 470 /* 471 * inode->i_mutex: down 472 */ 473 int 474 reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th, 475 struct inode *inode, const char *name, 476 const void *buffer, size_t buffer_size, int flags) 477 { 478 int err = 0; 479 struct dentry *dentry; 480 struct page *page; 481 char *data; 482 size_t file_pos = 0; 483 size_t buffer_pos = 0; 484 size_t new_size; 485 __u32 xahash = 0; 486 487 if (get_inode_sd_version(inode) == STAT_DATA_V1) 488 return -EOPNOTSUPP; 489 490 reiserfs_write_unlock(inode->i_sb); 491 492 if (!buffer) { 493 err = lookup_and_delete_xattr(inode, name); 494 reiserfs_write_lock(inode->i_sb); 495 return err; 496 } 497 498 dentry = xattr_lookup(inode, name, flags); 499 if (IS_ERR(dentry)) { 500 reiserfs_write_lock(inode->i_sb); 501 return PTR_ERR(dentry); 502 } 503 504 down_write(&REISERFS_I(inode)->i_xattr_sem); 505 506 reiserfs_write_lock(inode->i_sb); 507 508 xahash = xattr_hash(buffer, buffer_size); 509 while (buffer_pos < buffer_size || buffer_pos == 0) { 510 size_t chunk; 511 size_t skip = 0; 512 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 513 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 514 chunk = PAGE_CACHE_SIZE; 515 else 516 chunk = buffer_size - buffer_pos; 517 518 page = reiserfs_get_page(dentry->d_inode, file_pos); 519 if (IS_ERR(page)) { 520 err = PTR_ERR(page); 521 goto out_unlock; 522 } 523 524 lock_page(page); 525 data = page_address(page); 526 527 if (file_pos == 0) { 528 struct reiserfs_xattr_header *rxh; 529 skip = file_pos = sizeof(struct reiserfs_xattr_header); 530 if (chunk + skip > PAGE_CACHE_SIZE) 531 chunk = PAGE_CACHE_SIZE - skip; 532 rxh = (struct reiserfs_xattr_header *)data; 533 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 534 rxh->h_hash = cpu_to_le32(xahash); 535 } 536 537 err = reiserfs_prepare_write(NULL, page, page_offset, 538 page_offset + chunk + skip); 539 if (!err) { 540 if (buffer) 541 memcpy(data + skip, buffer + buffer_pos, chunk); 542 err = reiserfs_commit_write(NULL, page, page_offset, 543 page_offset + chunk + 544 skip); 545 } 546 unlock_page(page); 547 reiserfs_put_page(page); 548 buffer_pos += chunk; 549 file_pos += chunk; 550 skip = 0; 551 if (err || buffer_size == 0 || !buffer) 552 break; 553 } 554 555 new_size = buffer_size + sizeof(struct reiserfs_xattr_header); 556 if (!err && new_size < i_size_read(dentry->d_inode)) { 557 struct iattr newattrs = { 558 .ia_ctime = current_fs_time(inode->i_sb), 559 .ia_size = buffer_size, 560 .ia_valid = ATTR_SIZE | ATTR_CTIME, 561 }; 562 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 563 down_write(&dentry->d_inode->i_alloc_sem); 564 err = reiserfs_setattr(dentry, &newattrs); 565 up_write(&dentry->d_inode->i_alloc_sem); 566 mutex_unlock(&dentry->d_inode->i_mutex); 567 } else 568 update_ctime(inode); 569 out_unlock: 570 up_write(&REISERFS_I(inode)->i_xattr_sem); 571 dput(dentry); 572 return err; 573 } 574 575 /* We need to start a transaction to maintain lock ordering */ 576 int reiserfs_xattr_set(struct inode *inode, const char *name, 577 const void *buffer, size_t buffer_size, int flags) 578 { 579 580 struct reiserfs_transaction_handle th; 581 int error, error2; 582 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); 583 584 if (!(flags & XATTR_REPLACE)) 585 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); 586 587 reiserfs_write_lock(inode->i_sb); 588 error = journal_begin(&th, inode->i_sb, jbegin_count); 589 if (error) { 590 reiserfs_write_unlock(inode->i_sb); 591 return error; 592 } 593 594 error = reiserfs_xattr_set_handle(&th, inode, name, 595 buffer, buffer_size, flags); 596 597 error2 = journal_end(&th, inode->i_sb, jbegin_count); 598 if (error == 0) 599 error = error2; 600 reiserfs_write_unlock(inode->i_sb); 601 602 return error; 603 } 604 605 /* 606 * inode->i_mutex: down 607 */ 608 int 609 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, 610 size_t buffer_size) 611 { 612 ssize_t err = 0; 613 struct dentry *dentry; 614 size_t isize; 615 size_t file_pos = 0; 616 size_t buffer_pos = 0; 617 struct page *page; 618 __u32 hash = 0; 619 620 if (name == NULL) 621 return -EINVAL; 622 623 /* We can't have xattrs attached to v1 items since they don't have 624 * generation numbers */ 625 if (get_inode_sd_version(inode) == STAT_DATA_V1) 626 return -EOPNOTSUPP; 627 628 dentry = xattr_lookup(inode, name, XATTR_REPLACE); 629 if (IS_ERR(dentry)) { 630 err = PTR_ERR(dentry); 631 goto out; 632 } 633 634 down_read(&REISERFS_I(inode)->i_xattr_sem); 635 636 isize = i_size_read(dentry->d_inode); 637 638 /* Just return the size needed */ 639 if (buffer == NULL) { 640 err = isize - sizeof(struct reiserfs_xattr_header); 641 goto out_unlock; 642 } 643 644 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 645 err = -ERANGE; 646 goto out_unlock; 647 } 648 649 while (file_pos < isize) { 650 size_t chunk; 651 char *data; 652 size_t skip = 0; 653 if (isize - file_pos > PAGE_CACHE_SIZE) 654 chunk = PAGE_CACHE_SIZE; 655 else 656 chunk = isize - file_pos; 657 658 page = reiserfs_get_page(dentry->d_inode, file_pos); 659 if (IS_ERR(page)) { 660 err = PTR_ERR(page); 661 goto out_unlock; 662 } 663 664 lock_page(page); 665 data = page_address(page); 666 if (file_pos == 0) { 667 struct reiserfs_xattr_header *rxh = 668 (struct reiserfs_xattr_header *)data; 669 skip = file_pos = sizeof(struct reiserfs_xattr_header); 670 chunk -= skip; 671 /* Magic doesn't match up.. */ 672 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 673 unlock_page(page); 674 reiserfs_put_page(page); 675 reiserfs_warning(inode->i_sb, "jdm-20001", 676 "Invalid magic for xattr (%s) " 677 "associated with %k", name, 678 INODE_PKEY(inode)); 679 err = -EIO; 680 goto out_unlock; 681 } 682 hash = le32_to_cpu(rxh->h_hash); 683 } 684 memcpy(buffer + buffer_pos, data + skip, chunk); 685 unlock_page(page); 686 reiserfs_put_page(page); 687 file_pos += chunk; 688 buffer_pos += chunk; 689 skip = 0; 690 } 691 err = isize - sizeof(struct reiserfs_xattr_header); 692 693 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 694 hash) { 695 reiserfs_warning(inode->i_sb, "jdm-20002", 696 "Invalid hash for xattr (%s) associated " 697 "with %k", name, INODE_PKEY(inode)); 698 err = -EIO; 699 } 700 701 out_unlock: 702 up_read(&REISERFS_I(inode)->i_xattr_sem); 703 dput(dentry); 704 705 out: 706 return err; 707 } 708 709 /* 710 * In order to implement different sets of xattr operations for each xattr 711 * prefix with the generic xattr API, a filesystem should create a 712 * null-terminated array of struct xattr_handler (one for each prefix) and 713 * hang a pointer to it off of the s_xattr field of the superblock. 714 * 715 * The generic_fooxattr() functions will use this list to dispatch xattr 716 * operations to the correct xattr_handler. 717 */ 718 #define for_each_xattr_handler(handlers, handler) \ 719 for ((handler) = *(handlers)++; \ 720 (handler) != NULL; \ 721 (handler) = *(handlers)++) 722 723 /* This is the implementation for the xattr plugin infrastructure */ 724 static inline struct xattr_handler * 725 find_xattr_handler_prefix(struct xattr_handler **handlers, 726 const char *name) 727 { 728 struct xattr_handler *xah; 729 730 if (!handlers) 731 return NULL; 732 733 for_each_xattr_handler(handlers, xah) { 734 if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0) 735 break; 736 } 737 738 return xah; 739 } 740 741 742 /* 743 * Inode operation getxattr() 744 */ 745 ssize_t 746 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 747 size_t size) 748 { 749 struct inode *inode = dentry->d_inode; 750 struct xattr_handler *handler; 751 752 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 753 754 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 755 return -EOPNOTSUPP; 756 757 return handler->get(inode, name, buffer, size); 758 } 759 760 /* 761 * Inode operation setxattr() 762 * 763 * dentry->d_inode->i_mutex down 764 */ 765 int 766 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 767 size_t size, int flags) 768 { 769 struct inode *inode = dentry->d_inode; 770 struct xattr_handler *handler; 771 772 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 773 774 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 775 return -EOPNOTSUPP; 776 777 return handler->set(inode, name, value, size, 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 struct inode *inode = dentry->d_inode; 788 struct xattr_handler *handler; 789 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 790 791 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 792 return -EOPNOTSUPP; 793 794 return handler->set(inode, name, NULL, 0, XATTR_REPLACE); 795 } 796 797 struct listxattr_buf { 798 size_t size; 799 size_t pos; 800 char *buf; 801 struct inode *inode; 802 }; 803 804 static int listxattr_filler(void *buf, const char *name, int namelen, 805 loff_t offset, u64 ino, unsigned int d_type) 806 { 807 struct listxattr_buf *b = (struct listxattr_buf *)buf; 808 size_t size; 809 if (name[0] != '.' || 810 (namelen != 1 && (name[1] != '.' || namelen != 2))) { 811 struct xattr_handler *handler; 812 handler = find_xattr_handler_prefix(b->inode->i_sb->s_xattr, 813 name); 814 if (!handler) /* Unsupported xattr name */ 815 return 0; 816 if (b->buf) { 817 size = handler->list(b->inode, b->buf + b->pos, 818 b->size, name, namelen); 819 if (size > b->size) 820 return -ERANGE; 821 } else { 822 size = handler->list(b->inode, NULL, 0, name, namelen); 823 } 824 825 b->pos += size; 826 } 827 return 0; 828 } 829 830 /* 831 * Inode operation listxattr() 832 * 833 * We totally ignore the generic listxattr here because it would be stupid 834 * not to. Since the xattrs are organized in a directory, we can just 835 * readdir to find them. 836 */ 837 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 838 { 839 struct dentry *dir; 840 int err = 0; 841 loff_t pos = 0; 842 struct listxattr_buf buf = { 843 .inode = dentry->d_inode, 844 .buf = buffer, 845 .size = buffer ? size : 0, 846 }; 847 848 if (!dentry->d_inode) 849 return -EINVAL; 850 851 if (!dentry->d_sb->s_xattr || 852 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 853 return -EOPNOTSUPP; 854 855 dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); 856 if (IS_ERR(dir)) { 857 err = PTR_ERR(dir); 858 if (err == -ENODATA) 859 err = 0; /* Not an error if there aren't any xattrs */ 860 goto out; 861 } 862 863 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 864 err = reiserfs_readdir_dentry(dir, &buf, listxattr_filler, &pos); 865 mutex_unlock(&dir->d_inode->i_mutex); 866 867 if (!err) 868 err = buf.pos; 869 870 dput(dir); 871 out: 872 return err; 873 } 874 875 static int reiserfs_check_acl(struct inode *inode, int mask) 876 { 877 struct posix_acl *acl; 878 int error = -EAGAIN; /* do regular unix permission checks by default */ 879 880 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 881 882 if (acl) { 883 if (!IS_ERR(acl)) { 884 error = posix_acl_permission(inode, acl, mask); 885 posix_acl_release(acl); 886 } else if (PTR_ERR(acl) != -ENODATA) 887 error = PTR_ERR(acl); 888 } 889 890 return error; 891 } 892 893 static int create_privroot(struct dentry *dentry) 894 { 895 int err; 896 struct inode *inode = dentry->d_parent->d_inode; 897 WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex)); 898 899 err = xattr_mkdir(inode, dentry, 0700); 900 if (err || !dentry->d_inode) { 901 reiserfs_warning(dentry->d_sb, "jdm-20006", 902 "xattrs/ACLs enabled and couldn't " 903 "find/create .reiserfs_priv. " 904 "Failing mount."); 905 return -EOPNOTSUPP; 906 } 907 908 dentry->d_inode->i_flags |= S_PRIVATE; 909 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 910 "storage.\n", PRIVROOT_NAME); 911 912 return 0; 913 } 914 915 #else 916 int __init reiserfs_xattr_register_handlers(void) { return 0; } 917 void reiserfs_xattr_unregister_handlers(void) {} 918 static int create_privroot(struct dentry *dentry) { return 0; } 919 #endif 920 921 /* Actual operations that are exported to VFS-land */ 922 struct xattr_handler *reiserfs_xattr_handlers[] = { 923 #ifdef CONFIG_REISERFS_FS_XATTR 924 &reiserfs_xattr_user_handler, 925 &reiserfs_xattr_trusted_handler, 926 #endif 927 #ifdef CONFIG_REISERFS_FS_SECURITY 928 &reiserfs_xattr_security_handler, 929 #endif 930 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 931 &reiserfs_posix_acl_access_handler, 932 &reiserfs_posix_acl_default_handler, 933 #endif 934 NULL 935 }; 936 937 static int xattr_mount_check(struct super_block *s) 938 { 939 /* We need generation numbers to ensure that the oid mapping is correct 940 * v3.5 filesystems don't have them. */ 941 if (old_format_only(s)) { 942 if (reiserfs_xattrs_optional(s)) { 943 /* Old format filesystem, but optional xattrs have 944 * been enabled. Error out. */ 945 reiserfs_warning(s, "jdm-2005", 946 "xattrs/ACLs not supported " 947 "on pre-v3.6 format filesystems. " 948 "Failing mount."); 949 return -EOPNOTSUPP; 950 } 951 } 952 953 return 0; 954 } 955 956 int reiserfs_permission(struct inode *inode, int mask) 957 { 958 /* 959 * We don't do permission checks on the internal objects. 960 * Permissions are determined by the "owning" object. 961 */ 962 if (IS_PRIVATE(inode)) 963 return 0; 964 965 #ifdef CONFIG_REISERFS_FS_XATTR 966 /* 967 * Stat data v1 doesn't support ACLs. 968 */ 969 if (get_inode_sd_version(inode) != STAT_DATA_V1) 970 return generic_permission(inode, mask, reiserfs_check_acl); 971 #endif 972 return generic_permission(inode, mask, NULL); 973 } 974 975 /* This will catch lookups from the fs root to .reiserfs_priv */ 976 static int 977 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 978 { 979 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 980 if (container_of(q1, struct dentry, d_name) == priv_root) 981 return -ENOENT; 982 if (q1->len == name->len && 983 !memcmp(q1->name, name->name, name->len)) 984 return 0; 985 return 1; 986 } 987 988 static const struct dentry_operations xattr_lookup_poison_ops = { 989 .d_compare = xattr_lookup_poison, 990 }; 991 992 int reiserfs_lookup_privroot(struct super_block *s) 993 { 994 struct dentry *dentry; 995 int err = 0; 996 997 /* If we don't have the privroot located yet - go find it */ 998 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 999 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 1000 strlen(PRIVROOT_NAME)); 1001 if (!IS_ERR(dentry)) { 1002 REISERFS_SB(s)->priv_root = dentry; 1003 if (!reiserfs_expose_privroot(s)) 1004 s->s_root->d_op = &xattr_lookup_poison_ops; 1005 if (dentry->d_inode) 1006 dentry->d_inode->i_flags |= S_PRIVATE; 1007 } else 1008 err = PTR_ERR(dentry); 1009 mutex_unlock(&s->s_root->d_inode->i_mutex); 1010 1011 return err; 1012 } 1013 1014 /* We need to take a copy of the mount flags since things like 1015 * MS_RDONLY don't get set until *after* we're called. 1016 * mount_flags != mount_options */ 1017 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1018 { 1019 int err = 0; 1020 struct dentry *privroot = REISERFS_SB(s)->priv_root; 1021 1022 err = xattr_mount_check(s); 1023 if (err) 1024 goto error; 1025 1026 if (!privroot->d_inode && !(mount_flags & MS_RDONLY)) { 1027 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 1028 err = create_privroot(REISERFS_SB(s)->priv_root); 1029 mutex_unlock(&s->s_root->d_inode->i_mutex); 1030 } 1031 1032 if (privroot->d_inode) { 1033 s->s_xattr = reiserfs_xattr_handlers; 1034 reiserfs_mutex_lock_safe(&privroot->d_inode->i_mutex, s); 1035 if (!REISERFS_SB(s)->xattr_root) { 1036 struct dentry *dentry; 1037 dentry = lookup_one_len(XAROOT_NAME, privroot, 1038 strlen(XAROOT_NAME)); 1039 if (!IS_ERR(dentry)) 1040 REISERFS_SB(s)->xattr_root = dentry; 1041 else 1042 err = PTR_ERR(dentry); 1043 } 1044 mutex_unlock(&privroot->d_inode->i_mutex); 1045 } 1046 1047 error: 1048 if (err) { 1049 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1050 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1051 } 1052 1053 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1054 if (reiserfs_posixacl(s)) 1055 s->s_flags |= MS_POSIXACL; 1056 else 1057 s->s_flags &= ~MS_POSIXACL; 1058 1059 return err; 1060 } 1061