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/smp_lock.h> 50 #include <linux/stat.h> 51 #include <linux/quotaops.h> 52 53 #define PRIVROOT_NAME ".reiserfs_priv" 54 #define XAROOT_NAME "xattrs" 55 56 57 /* Helpers for inode ops. We do this so that we don't have all the VFS 58 * overhead and also for proper i_mutex annotation. 59 * dir->i_mutex must be held for all of them. */ 60 #ifdef CONFIG_REISERFS_FS_XATTR 61 static int xattr_create(struct inode *dir, struct dentry *dentry, int mode) 62 { 63 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 64 vfs_dq_init(dir); 65 return dir->i_op->create(dir, dentry, mode, NULL); 66 } 67 #endif 68 69 static int xattr_mkdir(struct inode *dir, struct dentry *dentry, int mode) 70 { 71 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 72 vfs_dq_init(dir); 73 return dir->i_op->mkdir(dir, dentry, mode); 74 } 75 76 /* We use I_MUTEX_CHILD here to silence lockdep. It's safe because xattr 77 * mutation ops aren't called during rename or splace, which are the 78 * only other users of I_MUTEX_CHILD. It violates the ordering, but that's 79 * better than allocating another subclass just for this code. */ 80 static int xattr_unlink(struct inode *dir, struct dentry *dentry) 81 { 82 int error; 83 BUG_ON(!mutex_is_locked(&dir->i_mutex)); 84 vfs_dq_init(dir); 85 86 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); 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 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_CHILD); 102 dentry_unhash(dentry); 103 error = dir->i_op->rmdir(dir, dentry); 104 if (!error) 105 dentry->d_inode->i_flags |= S_DEAD; 106 mutex_unlock(&dentry->d_inode->i_mutex); 107 if (!error) 108 d_delete(dentry); 109 dput(dentry); 110 111 return error; 112 } 113 114 #define xattr_may_create(flags) (!flags || flags & XATTR_CREATE) 115 116 static struct dentry *open_xa_root(struct super_block *sb, int flags) 117 { 118 struct dentry *privroot = REISERFS_SB(sb)->priv_root; 119 struct dentry *xaroot; 120 if (!privroot->d_inode) 121 return ERR_PTR(-ENODATA); 122 123 mutex_lock_nested(&privroot->d_inode->i_mutex, I_MUTEX_XATTR); 124 125 xaroot = dget(REISERFS_SB(sb)->xattr_root); 126 if (!xaroot->d_inode) { 127 int err = -ENODATA; 128 if (xattr_may_create(flags)) 129 err = xattr_mkdir(privroot->d_inode, xaroot, 0700); 130 if (err) { 131 dput(xaroot); 132 xaroot = ERR_PTR(err); 133 } 134 } 135 136 mutex_unlock(&privroot->d_inode->i_mutex); 137 return xaroot; 138 } 139 140 static struct dentry *open_xa_dir(const struct inode *inode, int flags) 141 { 142 struct dentry *xaroot, *xadir; 143 char namebuf[17]; 144 145 xaroot = open_xa_root(inode->i_sb, flags); 146 if (IS_ERR(xaroot)) 147 return xaroot; 148 149 snprintf(namebuf, sizeof(namebuf), "%X.%X", 150 le32_to_cpu(INODE_PKEY(inode)->k_objectid), 151 inode->i_generation); 152 153 mutex_lock_nested(&xaroot->d_inode->i_mutex, I_MUTEX_XATTR); 154 155 xadir = lookup_one_len(namebuf, xaroot, strlen(namebuf)); 156 if (!IS_ERR(xadir) && !xadir->d_inode) { 157 int err = -ENODATA; 158 if (xattr_may_create(flags)) 159 err = xattr_mkdir(xaroot->d_inode, xadir, 0700); 160 if (err) { 161 dput(xadir); 162 xadir = ERR_PTR(err); 163 } 164 } 165 166 mutex_unlock(&xaroot->d_inode->i_mutex); 167 dput(xaroot); 168 return xadir; 169 } 170 171 /* The following are side effects of other operations that aren't explicitly 172 * modifying extended attributes. This includes operations such as permissions 173 * or ownership changes, object deletions, etc. */ 174 struct reiserfs_dentry_buf { 175 struct dentry *xadir; 176 int count; 177 struct dentry *dentries[8]; 178 }; 179 180 static int 181 fill_with_dentries(void *buf, const char *name, int namelen, loff_t offset, 182 u64 ino, unsigned int d_type) 183 { 184 struct reiserfs_dentry_buf *dbuf = buf; 185 struct dentry *dentry; 186 WARN_ON_ONCE(!mutex_is_locked(&dbuf->xadir->d_inode->i_mutex)); 187 188 if (dbuf->count == ARRAY_SIZE(dbuf->dentries)) 189 return -ENOSPC; 190 191 if (name[0] == '.' && (name[1] == '\0' || 192 (name[1] == '.' && name[2] == '\0'))) 193 return 0; 194 195 dentry = lookup_one_len(name, dbuf->xadir, namelen); 196 if (IS_ERR(dentry)) { 197 return PTR_ERR(dentry); 198 } else if (!dentry->d_inode) { 199 /* A directory entry exists, but no file? */ 200 reiserfs_error(dentry->d_sb, "xattr-20003", 201 "Corrupted directory: xattr %s listed but " 202 "not found for file %s.\n", 203 dentry->d_name.name, dbuf->xadir->d_name.name); 204 dput(dentry); 205 return -EIO; 206 } 207 208 dbuf->dentries[dbuf->count++] = dentry; 209 return 0; 210 } 211 212 static void 213 cleanup_dentry_buf(struct reiserfs_dentry_buf *buf) 214 { 215 int i; 216 for (i = 0; i < buf->count; i++) 217 if (buf->dentries[i]) 218 dput(buf->dentries[i]); 219 } 220 221 static int reiserfs_for_each_xattr(struct inode *inode, 222 int (*action)(struct dentry *, void *), 223 void *data) 224 { 225 struct dentry *dir; 226 int i, err = 0; 227 loff_t pos = 0; 228 struct reiserfs_dentry_buf buf = { 229 .count = 0, 230 }; 231 232 /* Skip out, an xattr has no xattrs associated with it */ 233 if (IS_PRIVATE(inode) || get_inode_sd_version(inode) == STAT_DATA_V1) 234 return 0; 235 236 dir = open_xa_dir(inode, XATTR_REPLACE); 237 if (IS_ERR(dir)) { 238 err = PTR_ERR(dir); 239 goto out; 240 } else if (!dir->d_inode) { 241 err = 0; 242 goto out_dir; 243 } 244 245 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 246 buf.xadir = dir; 247 err = reiserfs_readdir_dentry(dir, &buf, fill_with_dentries, &pos); 248 while ((err == 0 || err == -ENOSPC) && buf.count) { 249 err = 0; 250 251 for (i = 0; i < buf.count && buf.dentries[i]; i++) { 252 int lerr = 0; 253 struct dentry *dentry = buf.dentries[i]; 254 255 if (err == 0 && !S_ISDIR(dentry->d_inode->i_mode)) 256 lerr = action(dentry, data); 257 258 dput(dentry); 259 buf.dentries[i] = NULL; 260 err = lerr ?: err; 261 } 262 buf.count = 0; 263 if (!err) 264 err = reiserfs_readdir_dentry(dir, &buf, 265 fill_with_dentries, &pos); 266 } 267 mutex_unlock(&dir->d_inode->i_mutex); 268 269 /* Clean up after a failed readdir */ 270 cleanup_dentry_buf(&buf); 271 272 if (!err) { 273 /* We start a transaction here to avoid a ABBA situation 274 * between the xattr root's i_mutex and the journal lock. 275 * This doesn't incur much additional overhead since the 276 * new transaction will just nest inside the 277 * outer transaction. */ 278 int blocks = JOURNAL_PER_BALANCE_CNT * 2 + 2 + 279 4 * REISERFS_QUOTA_TRANS_BLOCKS(inode->i_sb); 280 struct reiserfs_transaction_handle th; 281 err = journal_begin(&th, inode->i_sb, blocks); 282 if (!err) { 283 int jerror; 284 mutex_lock_nested(&dir->d_parent->d_inode->i_mutex, 285 I_MUTEX_XATTR); 286 err = action(dir, data); 287 jerror = journal_end(&th, inode->i_sb, blocks); 288 mutex_unlock(&dir->d_parent->d_inode->i_mutex); 289 err = jerror ?: err; 290 } 291 } 292 out_dir: 293 dput(dir); 294 out: 295 /* -ENODATA isn't an error */ 296 if (err == -ENODATA) 297 err = 0; 298 return err; 299 } 300 301 static int delete_one_xattr(struct dentry *dentry, void *data) 302 { 303 struct inode *dir = dentry->d_parent->d_inode; 304 305 /* This is the xattr dir, handle specially. */ 306 if (S_ISDIR(dentry->d_inode->i_mode)) 307 return xattr_rmdir(dir, dentry); 308 309 return xattr_unlink(dir, dentry); 310 } 311 312 static int chown_one_xattr(struct dentry *dentry, void *data) 313 { 314 struct iattr *attrs = data; 315 return reiserfs_setattr(dentry, attrs); 316 } 317 318 /* No i_mutex, but the inode is unconnected. */ 319 int reiserfs_delete_xattrs(struct inode *inode) 320 { 321 int err = reiserfs_for_each_xattr(inode, delete_one_xattr, NULL); 322 if (err) 323 reiserfs_warning(inode->i_sb, "jdm-20004", 324 "Couldn't delete all xattrs (%d)\n", err); 325 return err; 326 } 327 328 /* inode->i_mutex: down */ 329 int reiserfs_chown_xattrs(struct inode *inode, struct iattr *attrs) 330 { 331 int err = reiserfs_for_each_xattr(inode, chown_one_xattr, attrs); 332 if (err) 333 reiserfs_warning(inode->i_sb, "jdm-20007", 334 "Couldn't chown all xattrs (%d)\n", err); 335 return err; 336 } 337 338 #ifdef CONFIG_REISERFS_FS_XATTR 339 /* Returns a dentry corresponding to a specific extended attribute file 340 * for the inode. If flags allow, the file is created. Otherwise, a 341 * valid or negative dentry, or an error is returned. */ 342 static struct dentry *xattr_lookup(struct inode *inode, const char *name, 343 int flags) 344 { 345 struct dentry *xadir, *xafile; 346 int err = 0; 347 348 xadir = open_xa_dir(inode, flags); 349 if (IS_ERR(xadir)) 350 return ERR_CAST(xadir); 351 352 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 353 xafile = lookup_one_len(name, xadir, strlen(name)); 354 if (IS_ERR(xafile)) { 355 err = PTR_ERR(xafile); 356 goto out; 357 } 358 359 if (xafile->d_inode && (flags & XATTR_CREATE)) 360 err = -EEXIST; 361 362 if (!xafile->d_inode) { 363 err = -ENODATA; 364 if (xattr_may_create(flags)) 365 err = xattr_create(xadir->d_inode, xafile, 366 0700|S_IFREG); 367 } 368 369 if (err) 370 dput(xafile); 371 out: 372 mutex_unlock(&xadir->d_inode->i_mutex); 373 dput(xadir); 374 if (err) 375 return ERR_PTR(err); 376 return xafile; 377 } 378 379 /* Internal operations on file data */ 380 static inline void reiserfs_put_page(struct page *page) 381 { 382 kunmap(page); 383 page_cache_release(page); 384 } 385 386 static struct page *reiserfs_get_page(struct inode *dir, size_t n) 387 { 388 struct address_space *mapping = dir->i_mapping; 389 struct page *page; 390 /* We can deadlock if we try to free dentries, 391 and an unlink/rmdir has just occured - GFP_NOFS avoids this */ 392 mapping_set_gfp_mask(mapping, GFP_NOFS); 393 page = read_mapping_page(mapping, n >> PAGE_CACHE_SHIFT, NULL); 394 if (!IS_ERR(page)) { 395 kmap(page); 396 if (PageError(page)) 397 goto fail; 398 } 399 return page; 400 401 fail: 402 reiserfs_put_page(page); 403 return ERR_PTR(-EIO); 404 } 405 406 static inline __u32 xattr_hash(const char *msg, int len) 407 { 408 return csum_partial(msg, len, 0); 409 } 410 411 int reiserfs_commit_write(struct file *f, struct page *page, 412 unsigned from, unsigned to); 413 int reiserfs_prepare_write(struct file *f, struct page *page, 414 unsigned from, unsigned to); 415 416 static void update_ctime(struct inode *inode) 417 { 418 struct timespec now = current_fs_time(inode->i_sb); 419 if (hlist_unhashed(&inode->i_hash) || !inode->i_nlink || 420 timespec_equal(&inode->i_ctime, &now)) 421 return; 422 423 inode->i_ctime = CURRENT_TIME_SEC; 424 mark_inode_dirty(inode); 425 } 426 427 static int lookup_and_delete_xattr(struct inode *inode, const char *name) 428 { 429 int err = 0; 430 struct dentry *dentry, *xadir; 431 432 xadir = open_xa_dir(inode, XATTR_REPLACE); 433 if (IS_ERR(xadir)) 434 return PTR_ERR(xadir); 435 436 mutex_lock_nested(&xadir->d_inode->i_mutex, I_MUTEX_XATTR); 437 dentry = lookup_one_len(name, xadir, strlen(name)); 438 if (IS_ERR(dentry)) { 439 err = PTR_ERR(dentry); 440 goto out_dput; 441 } 442 443 if (dentry->d_inode) { 444 err = xattr_unlink(xadir->d_inode, dentry); 445 update_ctime(inode); 446 } 447 448 dput(dentry); 449 out_dput: 450 mutex_unlock(&xadir->d_inode->i_mutex); 451 dput(xadir); 452 return err; 453 } 454 455 456 /* Generic extended attribute operations that can be used by xa plugins */ 457 458 /* 459 * inode->i_mutex: down 460 */ 461 int 462 reiserfs_xattr_set_handle(struct reiserfs_transaction_handle *th, 463 struct inode *inode, const char *name, 464 const void *buffer, size_t buffer_size, int flags) 465 { 466 int err = 0; 467 struct dentry *dentry; 468 struct page *page; 469 char *data; 470 size_t file_pos = 0; 471 size_t buffer_pos = 0; 472 size_t new_size; 473 __u32 xahash = 0; 474 475 if (get_inode_sd_version(inode) == STAT_DATA_V1) 476 return -EOPNOTSUPP; 477 478 if (!buffer) 479 return lookup_and_delete_xattr(inode, name); 480 481 dentry = xattr_lookup(inode, name, flags); 482 if (IS_ERR(dentry)) 483 return PTR_ERR(dentry); 484 485 down_write(&REISERFS_I(inode)->i_xattr_sem); 486 487 xahash = xattr_hash(buffer, buffer_size); 488 while (buffer_pos < buffer_size || buffer_pos == 0) { 489 size_t chunk; 490 size_t skip = 0; 491 size_t page_offset = (file_pos & (PAGE_CACHE_SIZE - 1)); 492 if (buffer_size - buffer_pos > PAGE_CACHE_SIZE) 493 chunk = PAGE_CACHE_SIZE; 494 else 495 chunk = buffer_size - buffer_pos; 496 497 page = reiserfs_get_page(dentry->d_inode, file_pos); 498 if (IS_ERR(page)) { 499 err = PTR_ERR(page); 500 goto out_unlock; 501 } 502 503 lock_page(page); 504 data = page_address(page); 505 506 if (file_pos == 0) { 507 struct reiserfs_xattr_header *rxh; 508 skip = file_pos = sizeof(struct reiserfs_xattr_header); 509 if (chunk + skip > PAGE_CACHE_SIZE) 510 chunk = PAGE_CACHE_SIZE - skip; 511 rxh = (struct reiserfs_xattr_header *)data; 512 rxh->h_magic = cpu_to_le32(REISERFS_XATTR_MAGIC); 513 rxh->h_hash = cpu_to_le32(xahash); 514 } 515 516 err = reiserfs_prepare_write(NULL, page, page_offset, 517 page_offset + chunk + skip); 518 if (!err) { 519 if (buffer) 520 memcpy(data + skip, buffer + buffer_pos, chunk); 521 err = reiserfs_commit_write(NULL, page, page_offset, 522 page_offset + chunk + 523 skip); 524 } 525 unlock_page(page); 526 reiserfs_put_page(page); 527 buffer_pos += chunk; 528 file_pos += chunk; 529 skip = 0; 530 if (err || buffer_size == 0 || !buffer) 531 break; 532 } 533 534 new_size = buffer_size + sizeof(struct reiserfs_xattr_header); 535 if (!err && new_size < i_size_read(dentry->d_inode)) { 536 struct iattr newattrs = { 537 .ia_ctime = current_fs_time(inode->i_sb), 538 .ia_size = buffer_size, 539 .ia_valid = ATTR_SIZE | ATTR_CTIME, 540 }; 541 mutex_lock_nested(&dentry->d_inode->i_mutex, I_MUTEX_XATTR); 542 down_write(&dentry->d_inode->i_alloc_sem); 543 err = reiserfs_setattr(dentry, &newattrs); 544 up_write(&dentry->d_inode->i_alloc_sem); 545 mutex_unlock(&dentry->d_inode->i_mutex); 546 } else 547 update_ctime(inode); 548 out_unlock: 549 up_write(&REISERFS_I(inode)->i_xattr_sem); 550 dput(dentry); 551 return err; 552 } 553 554 /* We need to start a transaction to maintain lock ordering */ 555 int reiserfs_xattr_set(struct inode *inode, const char *name, 556 const void *buffer, size_t buffer_size, int flags) 557 { 558 559 struct reiserfs_transaction_handle th; 560 int error, error2; 561 size_t jbegin_count = reiserfs_xattr_nblocks(inode, buffer_size); 562 563 if (!(flags & XATTR_REPLACE)) 564 jbegin_count += reiserfs_xattr_jcreate_nblocks(inode); 565 566 reiserfs_write_lock(inode->i_sb); 567 error = journal_begin(&th, inode->i_sb, jbegin_count); 568 if (error) { 569 reiserfs_write_unlock(inode->i_sb); 570 return error; 571 } 572 573 error = reiserfs_xattr_set_handle(&th, inode, name, 574 buffer, buffer_size, flags); 575 576 error2 = journal_end(&th, inode->i_sb, jbegin_count); 577 if (error == 0) 578 error = error2; 579 reiserfs_write_unlock(inode->i_sb); 580 581 return error; 582 } 583 584 /* 585 * inode->i_mutex: down 586 */ 587 int 588 reiserfs_xattr_get(struct inode *inode, const char *name, void *buffer, 589 size_t buffer_size) 590 { 591 ssize_t err = 0; 592 struct dentry *dentry; 593 size_t isize; 594 size_t file_pos = 0; 595 size_t buffer_pos = 0; 596 struct page *page; 597 __u32 hash = 0; 598 599 if (name == NULL) 600 return -EINVAL; 601 602 /* We can't have xattrs attached to v1 items since they don't have 603 * generation numbers */ 604 if (get_inode_sd_version(inode) == STAT_DATA_V1) 605 return -EOPNOTSUPP; 606 607 dentry = xattr_lookup(inode, name, XATTR_REPLACE); 608 if (IS_ERR(dentry)) { 609 err = PTR_ERR(dentry); 610 goto out; 611 } 612 613 down_read(&REISERFS_I(inode)->i_xattr_sem); 614 615 isize = i_size_read(dentry->d_inode); 616 617 /* Just return the size needed */ 618 if (buffer == NULL) { 619 err = isize - sizeof(struct reiserfs_xattr_header); 620 goto out_unlock; 621 } 622 623 if (buffer_size < isize - sizeof(struct reiserfs_xattr_header)) { 624 err = -ERANGE; 625 goto out_unlock; 626 } 627 628 while (file_pos < isize) { 629 size_t chunk; 630 char *data; 631 size_t skip = 0; 632 if (isize - file_pos > PAGE_CACHE_SIZE) 633 chunk = PAGE_CACHE_SIZE; 634 else 635 chunk = isize - file_pos; 636 637 page = reiserfs_get_page(dentry->d_inode, file_pos); 638 if (IS_ERR(page)) { 639 err = PTR_ERR(page); 640 goto out_unlock; 641 } 642 643 lock_page(page); 644 data = page_address(page); 645 if (file_pos == 0) { 646 struct reiserfs_xattr_header *rxh = 647 (struct reiserfs_xattr_header *)data; 648 skip = file_pos = sizeof(struct reiserfs_xattr_header); 649 chunk -= skip; 650 /* Magic doesn't match up.. */ 651 if (rxh->h_magic != cpu_to_le32(REISERFS_XATTR_MAGIC)) { 652 unlock_page(page); 653 reiserfs_put_page(page); 654 reiserfs_warning(inode->i_sb, "jdm-20001", 655 "Invalid magic for xattr (%s) " 656 "associated with %k", name, 657 INODE_PKEY(inode)); 658 err = -EIO; 659 goto out_unlock; 660 } 661 hash = le32_to_cpu(rxh->h_hash); 662 } 663 memcpy(buffer + buffer_pos, data + skip, chunk); 664 unlock_page(page); 665 reiserfs_put_page(page); 666 file_pos += chunk; 667 buffer_pos += chunk; 668 skip = 0; 669 } 670 err = isize - sizeof(struct reiserfs_xattr_header); 671 672 if (xattr_hash(buffer, isize - sizeof(struct reiserfs_xattr_header)) != 673 hash) { 674 reiserfs_warning(inode->i_sb, "jdm-20002", 675 "Invalid hash for xattr (%s) associated " 676 "with %k", name, INODE_PKEY(inode)); 677 err = -EIO; 678 } 679 680 out_unlock: 681 up_read(&REISERFS_I(inode)->i_xattr_sem); 682 dput(dentry); 683 684 out: 685 return err; 686 } 687 688 /* 689 * In order to implement different sets of xattr operations for each xattr 690 * prefix with the generic xattr API, a filesystem should create a 691 * null-terminated array of struct xattr_handler (one for each prefix) and 692 * hang a pointer to it off of the s_xattr field of the superblock. 693 * 694 * The generic_fooxattr() functions will use this list to dispatch xattr 695 * operations to the correct xattr_handler. 696 */ 697 #define for_each_xattr_handler(handlers, handler) \ 698 for ((handler) = *(handlers)++; \ 699 (handler) != NULL; \ 700 (handler) = *(handlers)++) 701 702 /* This is the implementation for the xattr plugin infrastructure */ 703 static inline struct xattr_handler * 704 find_xattr_handler_prefix(struct xattr_handler **handlers, 705 const char *name) 706 { 707 struct xattr_handler *xah; 708 709 if (!handlers) 710 return NULL; 711 712 for_each_xattr_handler(handlers, xah) { 713 if (strncmp(xah->prefix, name, strlen(xah->prefix)) == 0) 714 break; 715 } 716 717 return xah; 718 } 719 720 721 /* 722 * Inode operation getxattr() 723 */ 724 ssize_t 725 reiserfs_getxattr(struct dentry * dentry, const char *name, void *buffer, 726 size_t size) 727 { 728 struct inode *inode = dentry->d_inode; 729 struct xattr_handler *handler; 730 731 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 732 733 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 734 return -EOPNOTSUPP; 735 736 return handler->get(inode, name, buffer, size); 737 } 738 739 /* 740 * Inode operation setxattr() 741 * 742 * dentry->d_inode->i_mutex down 743 */ 744 int 745 reiserfs_setxattr(struct dentry *dentry, const char *name, const void *value, 746 size_t size, int flags) 747 { 748 struct inode *inode = dentry->d_inode; 749 struct xattr_handler *handler; 750 751 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 752 753 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 754 return -EOPNOTSUPP; 755 756 return handler->set(inode, name, value, size, flags); 757 } 758 759 /* 760 * Inode operation removexattr() 761 * 762 * dentry->d_inode->i_mutex down 763 */ 764 int reiserfs_removexattr(struct dentry *dentry, const char *name) 765 { 766 struct inode *inode = dentry->d_inode; 767 struct xattr_handler *handler; 768 handler = find_xattr_handler_prefix(inode->i_sb->s_xattr, name); 769 770 if (!handler || get_inode_sd_version(inode) == STAT_DATA_V1) 771 return -EOPNOTSUPP; 772 773 return handler->set(inode, name, NULL, 0, XATTR_REPLACE); 774 } 775 776 struct listxattr_buf { 777 size_t size; 778 size_t pos; 779 char *buf; 780 struct inode *inode; 781 }; 782 783 static int listxattr_filler(void *buf, const char *name, int namelen, 784 loff_t offset, u64 ino, unsigned int d_type) 785 { 786 struct listxattr_buf *b = (struct listxattr_buf *)buf; 787 size_t size; 788 if (name[0] != '.' || 789 (namelen != 1 && (name[1] != '.' || namelen != 2))) { 790 struct xattr_handler *handler; 791 handler = find_xattr_handler_prefix(b->inode->i_sb->s_xattr, 792 name); 793 if (!handler) /* Unsupported xattr name */ 794 return 0; 795 if (b->buf) { 796 size = handler->list(b->inode, b->buf + b->pos, 797 b->size, name, namelen); 798 if (size > b->size) 799 return -ERANGE; 800 } else { 801 size = handler->list(b->inode, NULL, 0, name, namelen); 802 } 803 804 b->pos += size; 805 } 806 return 0; 807 } 808 809 /* 810 * Inode operation listxattr() 811 * 812 * We totally ignore the generic listxattr here because it would be stupid 813 * not to. Since the xattrs are organized in a directory, we can just 814 * readdir to find them. 815 */ 816 ssize_t reiserfs_listxattr(struct dentry * dentry, char *buffer, size_t size) 817 { 818 struct dentry *dir; 819 int err = 0; 820 loff_t pos = 0; 821 struct listxattr_buf buf = { 822 .inode = dentry->d_inode, 823 .buf = buffer, 824 .size = buffer ? size : 0, 825 }; 826 827 if (!dentry->d_inode) 828 return -EINVAL; 829 830 if (!dentry->d_sb->s_xattr || 831 get_inode_sd_version(dentry->d_inode) == STAT_DATA_V1) 832 return -EOPNOTSUPP; 833 834 dir = open_xa_dir(dentry->d_inode, XATTR_REPLACE); 835 if (IS_ERR(dir)) { 836 err = PTR_ERR(dir); 837 if (err == -ENODATA) 838 err = 0; /* Not an error if there aren't any xattrs */ 839 goto out; 840 } 841 842 mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_XATTR); 843 err = reiserfs_readdir_dentry(dir, &buf, listxattr_filler, &pos); 844 mutex_unlock(&dir->d_inode->i_mutex); 845 846 if (!err) 847 err = buf.pos; 848 849 dput(dir); 850 out: 851 return err; 852 } 853 854 static int reiserfs_check_acl(struct inode *inode, int mask) 855 { 856 struct posix_acl *acl; 857 int error = -EAGAIN; /* do regular unix permission checks by default */ 858 859 acl = reiserfs_get_acl(inode, ACL_TYPE_ACCESS); 860 861 if (acl) { 862 if (!IS_ERR(acl)) { 863 error = posix_acl_permission(inode, acl, mask); 864 posix_acl_release(acl); 865 } else if (PTR_ERR(acl) != -ENODATA) 866 error = PTR_ERR(acl); 867 } 868 869 return error; 870 } 871 872 int reiserfs_permission(struct inode *inode, int mask) 873 { 874 /* 875 * We don't do permission checks on the internal objects. 876 * Permissions are determined by the "owning" object. 877 */ 878 if (IS_PRIVATE(inode)) 879 return 0; 880 /* 881 * Stat data v1 doesn't support ACLs. 882 */ 883 if (get_inode_sd_version(inode) == STAT_DATA_V1) 884 return generic_permission(inode, mask, NULL); 885 else 886 return generic_permission(inode, mask, reiserfs_check_acl); 887 } 888 889 static int create_privroot(struct dentry *dentry) 890 { 891 int err; 892 struct inode *inode = dentry->d_parent->d_inode; 893 WARN_ON_ONCE(!mutex_is_locked(&inode->i_mutex)); 894 895 err = xattr_mkdir(inode, dentry, 0700); 896 if (err || !dentry->d_inode) { 897 reiserfs_warning(dentry->d_sb, "jdm-20006", 898 "xattrs/ACLs enabled and couldn't " 899 "find/create .reiserfs_priv. " 900 "Failing mount."); 901 return -EOPNOTSUPP; 902 } 903 904 dentry->d_inode->i_flags |= S_PRIVATE; 905 reiserfs_info(dentry->d_sb, "Created %s - reserved for xattr " 906 "storage.\n", PRIVROOT_NAME); 907 908 return 0; 909 } 910 911 #else 912 int __init reiserfs_xattr_register_handlers(void) { return 0; } 913 void reiserfs_xattr_unregister_handlers(void) {} 914 static int create_privroot(struct dentry *dentry) { return 0; } 915 #endif 916 917 /* Actual operations that are exported to VFS-land */ 918 struct xattr_handler *reiserfs_xattr_handlers[] = { 919 #ifdef CONFIG_REISERFS_FS_XATTR 920 &reiserfs_xattr_user_handler, 921 &reiserfs_xattr_trusted_handler, 922 #endif 923 #ifdef CONFIG_REISERFS_FS_SECURITY 924 &reiserfs_xattr_security_handler, 925 #endif 926 #ifdef CONFIG_REISERFS_FS_POSIX_ACL 927 &reiserfs_posix_acl_access_handler, 928 &reiserfs_posix_acl_default_handler, 929 #endif 930 NULL 931 }; 932 933 static int xattr_mount_check(struct super_block *s) 934 { 935 /* We need generation numbers to ensure that the oid mapping is correct 936 * v3.5 filesystems don't have them. */ 937 if (old_format_only(s)) { 938 if (reiserfs_xattrs_optional(s)) { 939 /* Old format filesystem, but optional xattrs have 940 * been enabled. Error out. */ 941 reiserfs_warning(s, "jdm-2005", 942 "xattrs/ACLs not supported " 943 "on pre-v3.6 format filesystems. " 944 "Failing mount."); 945 return -EOPNOTSUPP; 946 } 947 } 948 949 return 0; 950 } 951 952 /* This will catch lookups from the fs root to .reiserfs_priv */ 953 static int 954 xattr_lookup_poison(struct dentry *dentry, struct qstr *q1, struct qstr *name) 955 { 956 struct dentry *priv_root = REISERFS_SB(dentry->d_sb)->priv_root; 957 if (container_of(q1, struct dentry, d_name) == priv_root) 958 return -ENOENT; 959 if (q1->len == name->len && 960 !memcmp(q1->name, name->name, name->len)) 961 return 0; 962 return 1; 963 } 964 965 static const struct dentry_operations xattr_lookup_poison_ops = { 966 .d_compare = xattr_lookup_poison, 967 }; 968 969 int reiserfs_lookup_privroot(struct super_block *s) 970 { 971 struct dentry *dentry; 972 int err = 0; 973 974 /* If we don't have the privroot located yet - go find it */ 975 mutex_lock(&s->s_root->d_inode->i_mutex); 976 dentry = lookup_one_len(PRIVROOT_NAME, s->s_root, 977 strlen(PRIVROOT_NAME)); 978 if (!IS_ERR(dentry)) { 979 REISERFS_SB(s)->priv_root = dentry; 980 s->s_root->d_op = &xattr_lookup_poison_ops; 981 if (dentry->d_inode) 982 dentry->d_inode->i_flags |= S_PRIVATE; 983 } else 984 err = PTR_ERR(dentry); 985 mutex_unlock(&s->s_root->d_inode->i_mutex); 986 987 return err; 988 } 989 990 /* We need to take a copy of the mount flags since things like 991 * MS_RDONLY don't get set until *after* we're called. 992 * mount_flags != mount_options */ 993 int reiserfs_xattr_init(struct super_block *s, int mount_flags) 994 { 995 int err = 0; 996 struct dentry *privroot = REISERFS_SB(s)->priv_root; 997 998 err = xattr_mount_check(s); 999 if (err) 1000 goto error; 1001 1002 if (!privroot->d_inode && !(mount_flags & MS_RDONLY)) { 1003 mutex_lock(&s->s_root->d_inode->i_mutex); 1004 err = create_privroot(REISERFS_SB(s)->priv_root); 1005 mutex_unlock(&s->s_root->d_inode->i_mutex); 1006 } 1007 1008 if (privroot->d_inode) { 1009 s->s_xattr = reiserfs_xattr_handlers; 1010 mutex_lock(&privroot->d_inode->i_mutex); 1011 if (!REISERFS_SB(s)->xattr_root) { 1012 struct dentry *dentry; 1013 dentry = lookup_one_len(XAROOT_NAME, privroot, 1014 strlen(XAROOT_NAME)); 1015 if (!IS_ERR(dentry)) 1016 REISERFS_SB(s)->xattr_root = dentry; 1017 else 1018 err = PTR_ERR(dentry); 1019 } 1020 mutex_unlock(&privroot->d_inode->i_mutex); 1021 } 1022 1023 error: 1024 if (err) { 1025 clear_bit(REISERFS_XATTRS_USER, &(REISERFS_SB(s)->s_mount_opt)); 1026 clear_bit(REISERFS_POSIXACL, &(REISERFS_SB(s)->s_mount_opt)); 1027 } 1028 1029 /* The super_block MS_POSIXACL must mirror the (no)acl mount option. */ 1030 if (reiserfs_posixacl(s)) 1031 s->s_flags |= MS_POSIXACL; 1032 else 1033 s->s_flags &= ~MS_POSIXACL; 1034 1035 return err; 1036 } 1037