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 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); 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 vfs_dq_init(dir); 99 100 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); 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 mutex_lock_nested(&dir->d_parent->d_inode->i_mutex, 292 I_MUTEX_XATTR); 293 err = action(dir, data); 294 jerror = journal_end(&th, inode->i_sb, blocks); 295 mutex_unlock(&dir->d_parent->d_inode->i_mutex); 296 err = jerror ?: err; 297 } 298 } 299 out_dir: 300 dput(dir); 301 out: 302 /* -ENODATA isn't an error */ 303 if (err == -ENODATA) 304 err = 0; 305 return err; 306 } 307 308 static int delete_one_xattr(struct dentry *dentry, void *data) 309 { 310 struct inode *dir = dentry->d_parent->d_inode; 311 312 /* This is the xattr dir, handle specially. */ 313 if (S_ISDIR(dentry->d_inode->i_mode)) 314 return xattr_rmdir(dir, dentry); 315 316 return xattr_unlink(dir, dentry); 317 } 318 319 static int chown_one_xattr(struct dentry *dentry, void *data) 320 { 321 struct iattr *attrs = data; 322 return reiserfs_setattr(dentry, attrs); 323 } 324 325 /* No i_mutex, but the inode is unconnected. */ 326 int reiserfs_delete_xattrs(struct inode *inode) 327 { 328 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL); 329 if (err) 330 reiserfs_warning(inode->i_sb, "jdm-20004", 331 "Couldn't delete all xattrs (%d)\n", err); 332 return err; 333 } 334 335 /* inode->i_mutex: down */ 336 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 337 { 338 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs); 339 if (err) 340 reiserfs_warning(inode->i_sb, "jdm-20007", 341 "Couldn't chown all xattrs (%d)\n", err); 342 return err; 343 } 344 345 #ifdef CONFIG_REISERFS_FS_XATTR 346 /* Returns a dentry corresponding to a specific extended attribute file 347 * for the inode. If flags allow, the file is created. Otherwise, a 348 * valid or negative dentry, or an error is returned. */ 349 static struct dentry *xattr_lookup(struct inode *inode, const char *name, 350 int flags) 351 { 352 struct dentry *xadir, *xafile; 353 int err = 0; 354 355 xadir = open_xa_dir(inode, flags); 356 if (IS_ERR(xadir)) 357 return ERR_CAST(xadir); 358 359 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 360 xafile = lookup_one_len(name, xadir, strlen(name)); 361 if (IS_ERR(xafile)) { 362 err = PTR_ERR(xafile); 363 goto out; 364 } 365 366 if (xafile->d_inode && (flags & XATTR_CREATE)) 367 err = -EEXIST; 368 369 if (!xafile->d_inode) { 370 err = -ENODATA; 371 if (xattr_may_create(flags)) 372 err = xattr_create(xadir->d_inode, xafile, 373 0700|S_IFREG); 374 } 375 376 if (err) 377 dput(xafile); 378 out: 379 mutex_unlock(&xadir->d_inode->i_mutex); 380 dput(xadir); 381 if (err) 382 return ERR_PTR(err); 383 return xafile; 384 } 385 386 /* Internal operations on file data */ 387 static inline void reiserfs_put_page(struct page *page) 388 { 389 kunmap(page); 390 page_cache_release(page); 391 } 392 393 static struct page *reiserfs_get_page(struct inode *dir, size_t n) 394 { 395 struct address_space *mapping = dir->i_mapping; 396 struct page *page; 397 /* We can deadlock if we try to free dentries, 398 and an unlink/rmdir has just occured - GFP_NOFS avoids this */ 399 mapping_set_gfp_mask(mapping, GFP_NOFS); 400 page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); 401 if (!IS_ERR(page)) { 402 kmap(page); 403 if (PageError(page)) 404 goto fail; 405 } 406 return page; 407 408 fail: 409 reiserfs_put_page(page); 410 return ERR_PTR(-EIO); 411 } 412 413 static inline __u32 xattr_hash(const char *msg, int len) 414 { 415 return csum_partial(msg, len, 0); 416 } 417 418 int reiserfs_commit_write(struct file *f, struct page *page, 419 unsigned from, unsigned to); 420 int reiserfs_prepare_write(struct file *f, struct page *page, 421 unsigned from, unsigned to); 422 423 static void update_ctime(struct inode *inode) 424 { 425 struct timespec now = current_fs_time(inode->i_sb); 426 if (hlist_unhashed(&inode->i_hash) || !inode->i_nlink || 427 timespec_equal(&inode->i_ctime, &now)) 428 return; 429 430 inode->i_ctime = CURRENT_TIME_SEC; 431 mark_inode_dirty(inode); 432 } 433 434 static int lookup_and_delete_xattr(struct inode *inode, const char *name) 435 { 436 int err = 0; 437 struct dentry *dentry, *xadir; 438 439 xadir = open_xa_dir(inode, XATTR_REPLACE); 440 if (IS_ERR(xadir)) 441 return PTR_ERR(xadir); 442 443 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 444 dentry = lookup_one_len(name, xadir, strlen(name)); 445 if (IS_ERR(dentry)) { 446 err = PTR_ERR(dentry); 447 goto out_dput; 448 } 449 450 if (dentry->d_inode) { 451 err = xattr_unlink(xadir->d_inode, dentry); 452 update_ctime(inode); 453 } 454 455 dput(dentry); 456 out_dput: 457 mutex_unlock(&xadir->d_inode->i_mutex); 458 dput(xadir); 459 return err; 460 } 461 462 463 /* Generic extended attribute operations that can be used by xa plugins */ 464 465 /* 466 * inode->i_mutex: down 467 */ 468 int 469 reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th, 470 struct inode *inode, const char *name, 471 const void *buffer, size_t buffer_size, int flags) 472 { 473 int err = 0; 474 struct dentry *dentry; 475 struct page *page; 476 char *data; 477 size_t file_pos = 0; 478 size_t buffer_pos = 0; 479 size_t new_size; 480 __u32 xahash = 0; 481 482 if (get_inode_sd_version(inode) == STAT_DATA_V1) 483 return -EOPNOTSUPP; 484 485 if (!buffer) 486 return lookup_and_delete_xattr(inode, name); 487 488 dentry = xattr_lookup(inode, name, flags); 489 if (IS_ERR(dentry)) 490 return PTR_ERR(dentry); 491 492 reiserfs_down_read_safe(&REISERFS_I(inode)->i_xattr_sem, inode->i_sb); 493 494 xahash = xattr_hash(buffer, buffer_size); 495 while (buffer_pos < buffer_size || buffer_pos == 0) { 496 size_t chunk; 497 size_t skip = 0; 498 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 499 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 500 chunk = PAGE_CACHE_SIZE; 501 else 502 chunk = buffer_size - buffer_pos; 503 504 page = reiserfs_get_page(dentry->d_inode, file_pos); 505 if (IS_ERR(page)) { 506 err = PTR_ERR(page); 507 goto out_unlock; 508 } 509 510 lock_page(page); 511 data = page_address(page); 512 513 if (file_pos == 0) { 514 struct reiserfs_xattr_header *rxh; 515 skip = file_pos = sizeof(struct reiserfs_xattr_header); 516 if (chunk + skip > PAGE_CACHE_SIZE) 517 chunk = PAGE_CACHE_SIZE - skip; 518 rxh = (struct reiserfs_xattr_header *)data; 519 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 520 rxh->h_hash = cpu_to_le32(xahash); 521 } 522 523 err = reiserfs_prepare_write(NULL, page, page_offset, 524 page_offset + chunk + skip); 525 if (!err) { 526 if (buffer) 527 memcpy(data + skip, buffer + buffer_pos, chunk); 528 err = reiserfs_commit_write(NULL, page, page_offset, 529 page_offset + chunk + 530 skip); 531 } 532 unlock_page(page); 533 reiserfs_put_page(page); 534 buffer_pos += chunk; 535 file_pos += chunk; 536 skip = 0; 537 if (err || buffer_size == 0 || !buffer) 538 break; 539 } 540 541 new_size = buffer_size + sizeof(struct reiserfs_xattr_header); 542 if (!err && new_size < i_size_read(dentry->d_inode)) { 543 struct iattr newattrs = { 544 .ia_ctime = current_fs_time(inode->i_sb), 545 .ia_size = buffer_size, 546 .ia_valid = ATTR_SIZE | ATTR_CTIME, 547 }; 548 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 549 down_write(&dentry->d_inode->i_alloc_sem); 550 err = reiserfs_setattr(dentry, &newattrs); 551 up_write(&dentry->d_inode->i_alloc_sem); 552 mutex_unlock(&dentry->d_inode->i_mutex); 553 } else 554 update_ctime(inode); 555 out_unlock: 556 up_write(&REISERFS_I(inode)->i_xattr_sem); 557 dput(dentry); 558 return err; 559 } 560 561 /* We need to start a transaction to maintain lock ordering */ 562 int reiserfs_xattr_set(struct inode *inode, const char *name, 563 const void *buffer, size_t buffer_size, int flags) 564 { 565 566 struct reiserfs_transaction_handle th; 567 int error, error2; 568 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); 569 570 if (!(flags & XATTR_REPLACE)) 571 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); 572 573 reiserfs_write_lock(inode->i_sb); 574 error = journal_begin(&th, inode->i_sb, jbegin_count); 575 if (error) { 576 reiserfs_write_unlock(inode->i_sb); 577 return error; 578 } 579 580 error = reiserfs_xattr_set_handle(&th, inode, name, 581 buffer, buffer_size, flags); 582 583 error2 = journal_end(&th, inode->i_sb, jbegin_count); 584 if (error == 0) 585 error = error2; 586 reiserfs_write_unlock(inode->i_sb); 587 588 return error; 589 } 590 591 /* 592 * inode->i_mutex: down 593 */ 594 int 595 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, 596 size_t buffer_size) 597 { 598 ssize_t err = 0; 599 struct dentry *dentry; 600 size_t isize; 601 size_t file_pos = 0; 602 size_t buffer_pos = 0; 603 struct page *page; 604 __u32 hash = 0; 605 606 if (name == NULL) 607 return -EINVAL; 608 609 /* We can't have xattrs attached to v1 items since they don't have 610 * generation numbers */ 611 if (get_inode_sd_version(inode) == STAT_DATA_V1) 612 return -EOPNOTSUPP; 613 614 dentry = xattr_lookup(inode, name, XATTR_REPLACE); 615 if (IS_ERR(dentry)) { 616 err = PTR_ERR(dentry); 617 goto out; 618 } 619 620 down_read(&REISERFS_I(inode)->i_xattr_sem); 621 622 isize = i_size_read(dentry->d_inode); 623 624 /* Just return the size needed */ 625 if (buffer == NULL) { 626 err = isize - sizeof(struct reiserfs_xattr_header); 627 goto out_unlock; 628 } 629 630 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 631 err = -ERANGE; 632 goto out_unlock; 633 } 634 635 while (file_pos < isize) { 636 size_t chunk; 637 char *data; 638 size_t skip = 0; 639 if (isize - file_pos > PAGE_CACHE_SIZE) 640 chunk = PAGE_CACHE_SIZE; 641 else 642 chunk = isize - file_pos; 643 644 page = reiserfs_get_page(dentry->d_inode, file_pos); 645 if (IS_ERR(page)) { 646 err = PTR_ERR(page); 647 goto out_unlock; 648 } 649 650 lock_page(page); 651 data = page_address(page); 652 if (file_pos == 0) { 653 struct reiserfs_xattr_header *rxh = 654 (struct reiserfs_xattr_header *)data; 655 skip = file_pos = sizeof(struct reiserfs_xattr_header); 656 chunk -= skip; 657 /* Magic doesn't match up.. */ 658 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 659 unlock_page(page); 660 reiserfs_put_page(page); 661 reiserfs_warning(inode->i_sb, "jdm-20001", 662 "Invalid magic for xattr (%s) " 663 "associated with %k", name, 664 INODE_PKEY(inode)); 665 err = -EIO; 666 goto out_unlock; 667 } 668 hash = le32_to_cpu(rxh->h_hash); 669 } 670 memcpy(buffer + buffer_pos, data + skip, chunk); 671 unlock_page(page); 672 reiserfs_put_page(page); 673 file_pos += chunk; 674 buffer_pos += chunk; 675 skip = 0; 676 } 677 err = isize - sizeof(struct reiserfs_xattr_header); 678 679 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 680 hash) { 681 reiserfs_warning(inode->i_sb, "jdm-20002", 682 "Invalid hash for xattr (%s) associated " 683 "with %k", name, INODE_PKEY(inode)); 684 err = -EIO; 685 } 686 687 out_unlock: 688 up_read(&REISERFS_I(inode)->i_xattr_sem); 689 dput(dentry); 690 691 out: 692 return err; 693 } 694 695 /* 696 * In order to implement different sets of xattr operations for each xattr 697 * prefix with the generic xattr API, a filesystem should create a 698 * null-terminated array of struct xattr_handler (one for each prefix) and 699 * hang a pointer to it off of the s_xattr field of the superblock. 700 * 701 * The generic_fooxattr() functions will use this list to dispatch xattr 702 * operations to the correct xattr_handler. 703 */ 704 #define for_each_xattr_handler(handlers, handler) \ 705 for ((handler) = *(handlers)++; \ 706 (handler) != NULL; \ 707 (handler) = *(handlers)++) 708 709 /* This is the implementation for the xattr plugin infrastructure */ 710 static inline struct xattr_handler * 711 find_xattr_handler_prefix(struct xattr_handler **handlers, 712 const char *name) 713 { 714 struct xattr_handler *xah; 715 716 if (!handlers) 717 return NULL; 718 719 for_each_xattr_handler(handlers, xah) { 720 if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0) 721 break; 722 } 723 724 return xah; 725 } 726 727 728 /* 729 * Inode operation getxattr() 730 */ 731 ssize_t 732 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 733 size_t size) 734 { 735 struct inode *inode = dentry->d_inode; 736 struct xattr_handler *handler; 737 738 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 739 740 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 741 return -EOPNOTSUPP; 742 743 return handler->get(inode, name, buffer, size); 744 } 745 746 /* 747 * Inode operation setxattr() 748 * 749 * dentry->d_inode->i_mutex down 750 */ 751 int 752 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 753 size_t size, int flags) 754 { 755 struct inode *inode = dentry->d_inode; 756 struct xattr_handler *handler; 757 758 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 759 760 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 761 return -EOPNOTSUPP; 762 763 return handler->set(inode, name, value, size, flags); 764 } 765 766 /* 767 * Inode operation removexattr() 768 * 769 * dentry->d_inode->i_mutex down 770 */ 771 int reiserfs_removexattr(struct dentry *dentry, const char *name) 772 { 773 struct inode *inode = dentry->d_inode; 774 struct xattr_handler *handler; 775 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 776 777 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 778 return -EOPNOTSUPP; 779 780 return handler->set(inode, name, NULL, 0, XATTR_REPLACE); 781 } 782 783 struct listxattr_buf { 784 size_t size; 785 size_t pos; 786 char *buf; 787 struct inode *inode; 788 }; 789 790 static int listxattr_filler(void *buf, const char *name, int namelen, 791 loff_t offset, u64 ino, unsigned int d_type) 792 { 793 struct listxattr_buf *b = (struct listxattr_buf *)buf; 794 size_t size; 795 if (name[0] != '.' || 796 (namelen != 1 && (name[1] != '.' || namelen != 2))) { 797 struct xattr_handler *handler; 798 handler = find_xattr_handler_prefix(b->inode->i_sb->s_xattr, 799 name); 800 if (!handler) /* Unsupported xattr name */ 801 return 0; 802 if (b->buf) { 803 size = handler->list(b->inode, b->buf + b->pos, 804 b->size, name, namelen); 805 if (size > b->size) 806 return -ERANGE; 807 } else { 808 size = handler->list(b->inode, NULL, 0, name, namelen); 809 } 810 811 b->pos += size; 812 } 813 return 0; 814 } 815 816 /* 817 * Inode operation listxattr() 818 * 819 * We totally ignore the generic listxattr here because it would be stupid 820 * not to. Since the xattrs are organized in a directory, we can just 821 * readdir to find them. 822 */ 823 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 824 { 825 struct dentry *dir; 826 int err = 0; 827 loff_t pos = 0; 828 struct listxattr_buf buf = { 829 .inode = dentry->d_inode, 830 .buf = buffer, 831 .size = buffer ? size : 0, 832 }; 833 834 if (!dentry->d_inode) 835 return -EINVAL; 836 837 if (!dentry->d_sb->s_xattr || 838 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 839 return -EOPNOTSUPP; 840 841 dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); 842 if (IS_ERR(dir)) { 843 err = PTR_ERR(dir); 844 if (err == -ENODATA) 845 err = 0; /* Not an error if there aren't any xattrs */ 846 goto out; 847 } 848 849 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 850 err = reiserfs_readdir_dentry(dir, &buf, listxattr_filler, &pos); 851 mutex_unlock(&dir->d_inode->i_mutex); 852 853 if (!err) 854 err = buf.pos; 855 856 dput(dir); 857 out: 858 return err; 859 } 860 861 static int reiserfs_check_acl(struct inode *inode, int mask) 862 { 863 struct posix_acl *acl; 864 int error = -EAGAIN; /* do regular unix permission checks by default */ 865 866 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 867 868 if (acl) { 869 if (!IS_ERR(acl)) { 870 error = posix_acl_permission(inode, acl, mask); 871 posix_acl_release(acl); 872 } else if (PTR_ERR(acl) != -ENODATA) 873 error = PTR_ERR(acl); 874 } 875 876 return error; 877 } 878 879 static int create_privroot(struct dentry *dentry) 880 { 881 int err; 882 struct inode *inode = dentry->d_parent->d_inode; 883 WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex)); 884 885 err = xattr_mkdir(inode, dentry, 0700); 886 if (err || !dentry->d_inode) { 887 reiserfs_warning(dentry->d_sb, "jdm-20006", 888 "xattrs/ACLs enabled and couldn't " 889 "find/create .reiserfs_priv. " 890 "Failing mount."); 891 return -EOPNOTSUPP; 892 } 893 894 dentry->d_inode->i_flags |= S_PRIVATE; 895 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 896 "storage.\n", PRIVROOT_NAME); 897 898 return 0; 899 } 900 901 #else 902 int __init reiserfs_xattr_register_handlers(void) { return 0; } 903 void reiserfs_xattr_unregister_handlers(void) {} 904 static int create_privroot(struct dentry *dentry) { return 0; } 905 #endif 906 907 /* Actual operations that are exported to VFS-land */ 908 struct xattr_handler *reiserfs_xattr_handlers[] = { 909 #ifdef CONFIG_REISERFS_FS_XATTR 910 &reiserfs_xattr_user_handler, 911 &reiserfs_xattr_trusted_handler, 912 #endif 913 #ifdef CONFIG_REISERFS_FS_SECURITY 914 &reiserfs_xattr_security_handler, 915 #endif 916 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 917 &reiserfs_posix_acl_access_handler, 918 &reiserfs_posix_acl_default_handler, 919 #endif 920 NULL 921 }; 922 923 static int xattr_mount_check(struct super_block *s) 924 { 925 /* We need generation numbers to ensure that the oid mapping is correct 926 * v3.5 filesystems don't have them. */ 927 if (old_format_only(s)) { 928 if (reiserfs_xattrs_optional(s)) { 929 /* Old format filesystem, but optional xattrs have 930 * been enabled. Error out. */ 931 reiserfs_warning(s, "jdm-2005", 932 "xattrs/ACLs not supported " 933 "on pre-v3.6 format filesystems. " 934 "Failing mount."); 935 return -EOPNOTSUPP; 936 } 937 } 938 939 return 0; 940 } 941 942 int reiserfs_permission(struct inode *inode, int mask) 943 { 944 /* 945 * We don't do permission checks on the internal objects. 946 * Permissions are determined by the "owning" object. 947 */ 948 if (IS_PRIVATE(inode)) 949 return 0; 950 951 #ifdef CONFIG_REISERFS_FS_XATTR 952 /* 953 * Stat data v1 doesn't support ACLs. 954 */ 955 if (get_inode_sd_version(inode) != STAT_DATA_V1) 956 return generic_permission(inode, mask, reiserfs_check_acl); 957 #endif 958 return generic_permission(inode, mask, NULL); 959 } 960 961 /* This will catch lookups from the fs root to .reiserfs_priv */ 962 static int 963 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 964 { 965 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 966 if (container_of(q1, struct dentry, d_name) == priv_root) 967 return -ENOENT; 968 if (q1->len == name->len && 969 !memcmp(q1->name, name->name, name->len)) 970 return 0; 971 return 1; 972 } 973 974 static const struct dentry_operations xattr_lookup_poison_ops = { 975 .d_compare = xattr_lookup_poison, 976 }; 977 978 int reiserfs_lookup_privroot(struct super_block *s) 979 { 980 struct dentry *dentry; 981 int err = 0; 982 983 /* If we don't have the privroot located yet - go find it */ 984 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 985 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 986 strlen(PRIVROOT_NAME)); 987 if (!IS_ERR(dentry)) { 988 REISERFS_SB(s)->priv_root = dentry; 989 if (!reiserfs_expose_privroot(s)) 990 s->s_root->d_op = &xattr_lookup_poison_ops; 991 if (dentry->d_inode) 992 dentry->d_inode->i_flags |= S_PRIVATE; 993 } else 994 err = PTR_ERR(dentry); 995 mutex_unlock(&s->s_root->d_inode->i_mutex); 996 997 return err; 998 } 999 1000 /* We need to take a copy of the mount flags since things like 1001 * MS_RDONLY don't get set until *after* we're called. 1002 * mount_flags != mount_options */ 1003 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1004 { 1005 int err = 0; 1006 struct dentry *privroot = REISERFS_SB(s)->priv_root; 1007 1008 err = xattr_mount_check(s); 1009 if (err) 1010 goto error; 1011 1012 if (!privroot->d_inode && !(mount_flags & MS_RDONLY)) { 1013 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 1014 err = create_privroot(REISERFS_SB(s)->priv_root); 1015 mutex_unlock(&s->s_root->d_inode->i_mutex); 1016 } 1017 1018 if (privroot->d_inode) { 1019 s->s_xattr = reiserfs_xattr_handlers; 1020 reiserfs_mutex_lock_safe(&privroot->d_inode->i_mutex, s); 1021 if (!REISERFS_SB(s)->xattr_root) { 1022 struct dentry *dentry; 1023 dentry = lookup_one_len(XAROOT_NAME, privroot, 1024 strlen(XAROOT_NAME)); 1025 if (!IS_ERR(dentry)) 1026 REISERFS_SB(s)->xattr_root = dentry; 1027 else 1028 err = PTR_ERR(dentry); 1029 } 1030 mutex_unlock(&privroot->d_inode->i_mutex); 1031 } 1032 1033 error: 1034 if (err) { 1035 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1036 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1037 } 1038 1039 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1040 if (reiserfs_posixacl(s)) 1041 s->s_flags |= MS_POSIXACL; 1042 else 1043 s->s_flags &= ~MS_POSIXACL; 1044 1045 return err; 1046 } 1047