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