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 reiserfs_write_unlock(inode->i_sb); 489 dentry = xattr_lookup(inode, name, flags); 490 if (IS_ERR(dentry)) { 491 reiserfs_write_lock(inode->i_sb); 492 return PTR_ERR(dentry); 493 } 494 495 down_read(&REISERFS_I(inode)->i_xattr_sem); 496 497 reiserfs_write_lock(inode->i_sb); 498 499 xahash = xattr_hash(buffer, buffer_size); 500 while (buffer_pos < buffer_size || buffer_pos == 0) { 501 size_t chunk; 502 size_t skip = 0; 503 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 504 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 505 chunk = PAGE_CACHE_SIZE; 506 else 507 chunk = buffer_size - buffer_pos; 508 509 page = reiserfs_get_page(dentry->d_inode, file_pos); 510 if (IS_ERR(page)) { 511 err = PTR_ERR(page); 512 goto out_unlock; 513 } 514 515 lock_page(page); 516 data = page_address(page); 517 518 if (file_pos == 0) { 519 struct reiserfs_xattr_header *rxh; 520 skip = file_pos = sizeof(struct reiserfs_xattr_header); 521 if (chunk + skip > PAGE_CACHE_SIZE) 522 chunk = PAGE_CACHE_SIZE - skip; 523 rxh = (struct reiserfs_xattr_header *)data; 524 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 525 rxh->h_hash = cpu_to_le32(xahash); 526 } 527 528 err = reiserfs_prepare_write(NULL, page, page_offset, 529 page_offset + chunk + skip); 530 if (!err) { 531 if (buffer) 532 memcpy(data + skip, buffer + buffer_pos, chunk); 533 err = reiserfs_commit_write(NULL, page, page_offset, 534 page_offset + chunk + 535 skip); 536 } 537 unlock_page(page); 538 reiserfs_put_page(page); 539 buffer_pos += chunk; 540 file_pos += chunk; 541 skip = 0; 542 if (err || buffer_size == 0 || !buffer) 543 break; 544 } 545 546 new_size = buffer_size + sizeof(struct reiserfs_xattr_header); 547 if (!err && new_size < i_size_read(dentry->d_inode)) { 548 struct iattr newattrs = { 549 .ia_ctime = current_fs_time(inode->i_sb), 550 .ia_size = buffer_size, 551 .ia_valid = ATTR_SIZE | ATTR_CTIME, 552 }; 553 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 554 down_write(&dentry->d_inode->i_alloc_sem); 555 err = reiserfs_setattr(dentry, &newattrs); 556 up_write(&dentry->d_inode->i_alloc_sem); 557 mutex_unlock(&dentry->d_inode->i_mutex); 558 } else 559 update_ctime(inode); 560 out_unlock: 561 up_write(&REISERFS_I(inode)->i_xattr_sem); 562 dput(dentry); 563 return err; 564 } 565 566 /* We need to start a transaction to maintain lock ordering */ 567 int reiserfs_xattr_set(struct inode *inode, const char *name, 568 const void *buffer, size_t buffer_size, int flags) 569 { 570 571 struct reiserfs_transaction_handle th; 572 int error, error2; 573 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); 574 575 if (!(flags & XATTR_REPLACE)) 576 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); 577 578 reiserfs_write_lock(inode->i_sb); 579 error = journal_begin(&th, inode->i_sb, jbegin_count); 580 if (error) { 581 reiserfs_write_unlock(inode->i_sb); 582 return error; 583 } 584 585 error = reiserfs_xattr_set_handle(&th, inode, name, 586 buffer, buffer_size, flags); 587 588 error2 = journal_end(&th, inode->i_sb, jbegin_count); 589 if (error == 0) 590 error = error2; 591 reiserfs_write_unlock(inode->i_sb); 592 593 return error; 594 } 595 596 /* 597 * inode->i_mutex: down 598 */ 599 int 600 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, 601 size_t buffer_size) 602 { 603 ssize_t err = 0; 604 struct dentry *dentry; 605 size_t isize; 606 size_t file_pos = 0; 607 size_t buffer_pos = 0; 608 struct page *page; 609 __u32 hash = 0; 610 611 if (name == NULL) 612 return -EINVAL; 613 614 /* We can't have xattrs attached to v1 items since they don't have 615 * generation numbers */ 616 if (get_inode_sd_version(inode) == STAT_DATA_V1) 617 return -EOPNOTSUPP; 618 619 dentry = xattr_lookup(inode, name, XATTR_REPLACE); 620 if (IS_ERR(dentry)) { 621 err = PTR_ERR(dentry); 622 goto out; 623 } 624 625 down_read(&REISERFS_I(inode)->i_xattr_sem); 626 627 isize = i_size_read(dentry->d_inode); 628 629 /* Just return the size needed */ 630 if (buffer == NULL) { 631 err = isize - sizeof(struct reiserfs_xattr_header); 632 goto out_unlock; 633 } 634 635 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 636 err = -ERANGE; 637 goto out_unlock; 638 } 639 640 while (file_pos < isize) { 641 size_t chunk; 642 char *data; 643 size_t skip = 0; 644 if (isize - file_pos > PAGE_CACHE_SIZE) 645 chunk = PAGE_CACHE_SIZE; 646 else 647 chunk = isize - file_pos; 648 649 page = reiserfs_get_page(dentry->d_inode, file_pos); 650 if (IS_ERR(page)) { 651 err = PTR_ERR(page); 652 goto out_unlock; 653 } 654 655 lock_page(page); 656 data = page_address(page); 657 if (file_pos == 0) { 658 struct reiserfs_xattr_header *rxh = 659 (struct reiserfs_xattr_header *)data; 660 skip = file_pos = sizeof(struct reiserfs_xattr_header); 661 chunk -= skip; 662 /* Magic doesn't match up.. */ 663 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 664 unlock_page(page); 665 reiserfs_put_page(page); 666 reiserfs_warning(inode->i_sb, "jdm-20001", 667 "Invalid magic for xattr (%s) " 668 "associated with %k", name, 669 INODE_PKEY(inode)); 670 err = -EIO; 671 goto out_unlock; 672 } 673 hash = le32_to_cpu(rxh->h_hash); 674 } 675 memcpy(buffer + buffer_pos, data + skip, chunk); 676 unlock_page(page); 677 reiserfs_put_page(page); 678 file_pos += chunk; 679 buffer_pos += chunk; 680 skip = 0; 681 } 682 err = isize - sizeof(struct reiserfs_xattr_header); 683 684 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 685 hash) { 686 reiserfs_warning(inode->i_sb, "jdm-20002", 687 "Invalid hash for xattr (%s) associated " 688 "with %k", name, INODE_PKEY(inode)); 689 err = -EIO; 690 } 691 692 out_unlock: 693 up_read(&REISERFS_I(inode)->i_xattr_sem); 694 dput(dentry); 695 696 out: 697 return err; 698 } 699 700 /* 701 * In order to implement different sets of xattr operations for each xattr 702 * prefix with the generic xattr API, a filesystem should create a 703 * null-terminated array of struct xattr_handler (one for each prefix) and 704 * hang a pointer to it off of the s_xattr field of the superblock. 705 * 706 * The generic_fooxattr() functions will use this list to dispatch xattr 707 * operations to the correct xattr_handler. 708 */ 709 #define for_each_xattr_handler(handlers, handler) \ 710 for ((handler) = *(handlers)++; \ 711 (handler) != NULL; \ 712 (handler) = *(handlers)++) 713 714 /* This is the implementation for the xattr plugin infrastructure */ 715 static inline struct xattr_handler * 716 find_xattr_handler_prefix(struct xattr_handler **handlers, 717 const char *name) 718 { 719 struct xattr_handler *xah; 720 721 if (!handlers) 722 return NULL; 723 724 for_each_xattr_handler(handlers, xah) { 725 if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0) 726 break; 727 } 728 729 return xah; 730 } 731 732 733 /* 734 * Inode operation getxattr() 735 */ 736 ssize_t 737 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 738 size_t size) 739 { 740 struct inode *inode = dentry->d_inode; 741 struct xattr_handler *handler; 742 743 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 744 745 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 746 return -EOPNOTSUPP; 747 748 return handler->get(inode, name, buffer, size); 749 } 750 751 /* 752 * Inode operation setxattr() 753 * 754 * dentry->d_inode->i_mutex down 755 */ 756 int 757 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 758 size_t size, int flags) 759 { 760 struct inode *inode = dentry->d_inode; 761 struct xattr_handler *handler; 762 763 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 764 765 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 766 return -EOPNOTSUPP; 767 768 return handler->set(inode, name, value, size, flags); 769 } 770 771 /* 772 * Inode operation removexattr() 773 * 774 * dentry->d_inode->i_mutex down 775 */ 776 int reiserfs_removexattr(struct dentry *dentry, const char *name) 777 { 778 struct inode *inode = dentry->d_inode; 779 struct xattr_handler *handler; 780 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 781 782 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 783 return -EOPNOTSUPP; 784 785 return handler->set(inode, name, NULL, 0, XATTR_REPLACE); 786 } 787 788 struct listxattr_buf { 789 size_t size; 790 size_t pos; 791 char *buf; 792 struct inode *inode; 793 }; 794 795 static int listxattr_filler(void *buf, const char *name, int namelen, 796 loff_t offset, u64 ino, unsigned int d_type) 797 { 798 struct listxattr_buf *b = (struct listxattr_buf *)buf; 799 size_t size; 800 if (name[0] != '.' || 801 (namelen != 1 && (name[1] != '.' || namelen != 2))) { 802 struct xattr_handler *handler; 803 handler = find_xattr_handler_prefix(b->inode->i_sb->s_xattr, 804 name); 805 if (!handler) /* Unsupported xattr name */ 806 return 0; 807 if (b->buf) { 808 size = handler->list(b->inode, b->buf + b->pos, 809 b->size, name, namelen); 810 if (size > b->size) 811 return -ERANGE; 812 } else { 813 size = handler->list(b->inode, NULL, 0, name, namelen); 814 } 815 816 b->pos += size; 817 } 818 return 0; 819 } 820 821 /* 822 * Inode operation listxattr() 823 * 824 * We totally ignore the generic listxattr here because it would be stupid 825 * not to. Since the xattrs are organized in a directory, we can just 826 * readdir to find them. 827 */ 828 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 829 { 830 struct dentry *dir; 831 int err = 0; 832 loff_t pos = 0; 833 struct listxattr_buf buf = { 834 .inode = dentry->d_inode, 835 .buf = buffer, 836 .size = buffer ? size : 0, 837 }; 838 839 if (!dentry->d_inode) 840 return -EINVAL; 841 842 if (!dentry->d_sb->s_xattr || 843 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 844 return -EOPNOTSUPP; 845 846 dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); 847 if (IS_ERR(dir)) { 848 err = PTR_ERR(dir); 849 if (err == -ENODATA) 850 err = 0; /* Not an error if there aren't any xattrs */ 851 goto out; 852 } 853 854 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 855 err = reiserfs_readdir_dentry(dir, &buf, listxattr_filler, &pos); 856 mutex_unlock(&dir->d_inode->i_mutex); 857 858 if (!err) 859 err = buf.pos; 860 861 dput(dir); 862 out: 863 return err; 864 } 865 866 static int reiserfs_check_acl(struct inode *inode, int mask) 867 { 868 struct posix_acl *acl; 869 int error = -EAGAIN; /* do regular unix permission checks by default */ 870 871 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 872 873 if (acl) { 874 if (!IS_ERR(acl)) { 875 error = posix_acl_permission(inode, acl, mask); 876 posix_acl_release(acl); 877 } else if (PTR_ERR(acl) != -ENODATA) 878 error = PTR_ERR(acl); 879 } 880 881 return error; 882 } 883 884 static int create_privroot(struct dentry *dentry) 885 { 886 int err; 887 struct inode *inode = dentry->d_parent->d_inode; 888 WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex)); 889 890 err = xattr_mkdir(inode, dentry, 0700); 891 if (err || !dentry->d_inode) { 892 reiserfs_warning(dentry->d_sb, "jdm-20006", 893 "xattrs/ACLs enabled and couldn't " 894 "find/create .reiserfs_priv. " 895 "Failing mount."); 896 return -EOPNOTSUPP; 897 } 898 899 dentry->d_inode->i_flags |= S_PRIVATE; 900 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 901 "storage.\n", PRIVROOT_NAME); 902 903 return 0; 904 } 905 906 #else 907 int __init reiserfs_xattr_register_handlers(void) { return 0; } 908 void reiserfs_xattr_unregister_handlers(void) {} 909 static int create_privroot(struct dentry *dentry) { return 0; } 910 #endif 911 912 /* Actual operations that are exported to VFS-land */ 913 struct xattr_handler *reiserfs_xattr_handlers[] = { 914 #ifdef CONFIG_REISERFS_FS_XATTR 915 &reiserfs_xattr_user_handler, 916 &reiserfs_xattr_trusted_handler, 917 #endif 918 #ifdef CONFIG_REISERFS_FS_SECURITY 919 &reiserfs_xattr_security_handler, 920 #endif 921 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 922 &reiserfs_posix_acl_access_handler, 923 &reiserfs_posix_acl_default_handler, 924 #endif 925 NULL 926 }; 927 928 static int xattr_mount_check(struct super_block *s) 929 { 930 /* We need generation numbers to ensure that the oid mapping is correct 931 * v3.5 filesystems don't have them. */ 932 if (old_format_only(s)) { 933 if (reiserfs_xattrs_optional(s)) { 934 /* Old format filesystem, but optional xattrs have 935 * been enabled. Error out. */ 936 reiserfs_warning(s, "jdm-2005", 937 "xattrs/ACLs not supported " 938 "on pre-v3.6 format filesystems. " 939 "Failing mount."); 940 return -EOPNOTSUPP; 941 } 942 } 943 944 return 0; 945 } 946 947 int reiserfs_permission(struct inode *inode, int mask) 948 { 949 /* 950 * We don't do permission checks on the internal objects. 951 * Permissions are determined by the "owning" object. 952 */ 953 if (IS_PRIVATE(inode)) 954 return 0; 955 956 #ifdef CONFIG_REISERFS_FS_XATTR 957 /* 958 * Stat data v1 doesn't support ACLs. 959 */ 960 if (get_inode_sd_version(inode) != STAT_DATA_V1) 961 return generic_permission(inode, mask, reiserfs_check_acl); 962 #endif 963 return generic_permission(inode, mask, NULL); 964 } 965 966 /* This will catch lookups from the fs root to .reiserfs_priv */ 967 static int 968 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 969 { 970 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 971 if (container_of(q1, struct dentry, d_name) == priv_root) 972 return -ENOENT; 973 if (q1->len == name->len && 974 !memcmp(q1->name, name->name, name->len)) 975 return 0; 976 return 1; 977 } 978 979 static const struct dentry_operations xattr_lookup_poison_ops = { 980 .d_compare = xattr_lookup_poison, 981 }; 982 983 int reiserfs_lookup_privroot(struct super_block *s) 984 { 985 struct dentry *dentry; 986 int err = 0; 987 988 /* If we don't have the privroot located yet - go find it */ 989 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 990 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 991 strlen(PRIVROOT_NAME)); 992 if (!IS_ERR(dentry)) { 993 REISERFS_SB(s)->priv_root = dentry; 994 if (!reiserfs_expose_privroot(s)) 995 s->s_root->d_op = &xattr_lookup_poison_ops; 996 if (dentry->d_inode) 997 dentry->d_inode->i_flags |= S_PRIVATE; 998 } else 999 err = PTR_ERR(dentry); 1000 mutex_unlock(&s->s_root->d_inode->i_mutex); 1001 1002 return err; 1003 } 1004 1005 /* We need to take a copy of the mount flags since things like 1006 * MS_RDONLY don't get set until *after* we're called. 1007 * mount_flags != mount_options */ 1008 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 1009 { 1010 int err = 0; 1011 struct dentry *privroot = REISERFS_SB(s)->priv_root; 1012 1013 err = xattr_mount_check(s); 1014 if (err) 1015 goto error; 1016 1017 if (!privroot->d_inode && !(mount_flags & MS_RDONLY)) { 1018 reiserfs_mutex_lock_safe(&s->s_root->d_inode->i_mutex, s); 1019 err = create_privroot(REISERFS_SB(s)->priv_root); 1020 mutex_unlock(&s->s_root->d_inode->i_mutex); 1021 } 1022 1023 if (privroot->d_inode) { 1024 s->s_xattr = reiserfs_xattr_handlers; 1025 reiserfs_mutex_lock_safe(&privroot->d_inode->i_mutex, s); 1026 if (!REISERFS_SB(s)->xattr_root) { 1027 struct dentry *dentry; 1028 dentry = lookup_one_len(XAROOT_NAME, privroot, 1029 strlen(XAROOT_NAME)); 1030 if (!IS_ERR(dentry)) 1031 REISERFS_SB(s)->xattr_root = dentry; 1032 else 1033 err = PTR_ERR(dentry); 1034 } 1035 mutex_unlock(&privroot->d_inode->i_mutex); 1036 } 1037 1038 error: 1039 if (err) { 1040 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1041 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1042 } 1043 1044 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1045 if (reiserfs_posixacl(s)) 1046 s->s_flags |= MS_POSIXACL; 1047 else 1048 s->s_flags &= ~MS_POSIXACL; 1049 1050 return err; 1051 } 1052