1 /* 2 * linux/fs/ext4/xattr.c 3 * 4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de> 5 * 6 * Fix by Harrison Xing <harrison@mountainviewdata.com>. 7 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>. 8 * Extended attributes for symlinks and special files added per 9 * suggestion of Luka Renko <luka.renko@hermes.si>. 10 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>, 11 * Red Hat Inc. 12 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz 13 * and Andreas Gruenbacher <agruen@suse.de>. 14 */ 15 16 /* 17 * Extended attributes are stored directly in inodes (on file systems with 18 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl 19 * field contains the block number if an inode uses an additional block. All 20 * attributes must fit in the inode and one additional block. Blocks that 21 * contain the identical set of attributes may be shared among several inodes. 22 * Identical blocks are detected by keeping a cache of blocks that have 23 * recently been accessed. 24 * 25 * The attributes in inodes and on blocks have a different header; the entries 26 * are stored in the same format: 27 * 28 * +------------------+ 29 * | header | 30 * | entry 1 | | 31 * | entry 2 | | growing downwards 32 * | entry 3 | v 33 * | four null bytes | 34 * | . . . | 35 * | value 1 | ^ 36 * | value 3 | | growing upwards 37 * | value 2 | | 38 * +------------------+ 39 * 40 * The header is followed by multiple entry descriptors. In disk blocks, the 41 * entry descriptors are kept sorted. In inodes, they are unsorted. The 42 * attribute values are aligned to the end of the block in no specific order. 43 * 44 * Locking strategy 45 * ---------------- 46 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem. 47 * EA blocks are only changed if they are exclusive to an inode, so 48 * holding xattr_sem also means that nothing but the EA block's reference 49 * count can change. Multiple writers to the same block are synchronized 50 * by the buffer lock. 51 */ 52 53 #include <linux/init.h> 54 #include <linux/fs.h> 55 #include <linux/slab.h> 56 #include <linux/ext4_jbd2.h> 57 #include <linux/ext4_fs.h> 58 #include <linux/mbcache.h> 59 #include <linux/quotaops.h> 60 #include <linux/rwsem.h> 61 #include "xattr.h" 62 #include "acl.h" 63 64 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data)) 65 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr)) 66 #define BFIRST(bh) ENTRY(BHDR(bh)+1) 67 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0) 68 69 #ifdef EXT4_XATTR_DEBUG 70 # define ea_idebug(inode, f...) do { \ 71 printk(KERN_DEBUG "inode %s:%lu: ", \ 72 inode->i_sb->s_id, inode->i_ino); \ 73 printk(f); \ 74 printk("\n"); \ 75 } while (0) 76 # define ea_bdebug(bh, f...) do { \ 77 char b[BDEVNAME_SIZE]; \ 78 printk(KERN_DEBUG "block %s:%lu: ", \ 79 bdevname(bh->b_bdev, b), \ 80 (unsigned long) bh->b_blocknr); \ 81 printk(f); \ 82 printk("\n"); \ 83 } while (0) 84 #else 85 # define ea_idebug(f...) 86 # define ea_bdebug(f...) 87 #endif 88 89 static void ext4_xattr_cache_insert(struct buffer_head *); 90 static struct buffer_head *ext4_xattr_cache_find(struct inode *, 91 struct ext4_xattr_header *, 92 struct mb_cache_entry **); 93 static void ext4_xattr_rehash(struct ext4_xattr_header *, 94 struct ext4_xattr_entry *); 95 96 static struct mb_cache *ext4_xattr_cache; 97 98 static struct xattr_handler *ext4_xattr_handler_map[] = { 99 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler, 100 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL 101 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler, 102 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler, 103 #endif 104 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler, 105 #ifdef CONFIG_EXT4DEV_FS_SECURITY 106 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler, 107 #endif 108 }; 109 110 struct xattr_handler *ext4_xattr_handlers[] = { 111 &ext4_xattr_user_handler, 112 &ext4_xattr_trusted_handler, 113 #ifdef CONFIG_EXT4DEV_FS_POSIX_ACL 114 &ext4_xattr_acl_access_handler, 115 &ext4_xattr_acl_default_handler, 116 #endif 117 #ifdef CONFIG_EXT4DEV_FS_SECURITY 118 &ext4_xattr_security_handler, 119 #endif 120 NULL 121 }; 122 123 static inline struct xattr_handler * 124 ext4_xattr_handler(int name_index) 125 { 126 struct xattr_handler *handler = NULL; 127 128 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map)) 129 handler = ext4_xattr_handler_map[name_index]; 130 return handler; 131 } 132 133 /* 134 * Inode operation listxattr() 135 * 136 * dentry->d_inode->i_mutex: don't care 137 */ 138 ssize_t 139 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size) 140 { 141 return ext4_xattr_list(dentry->d_inode, buffer, size); 142 } 143 144 static int 145 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end) 146 { 147 while (!IS_LAST_ENTRY(entry)) { 148 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry); 149 if ((void *)next >= end) 150 return -EIO; 151 entry = next; 152 } 153 return 0; 154 } 155 156 static inline int 157 ext4_xattr_check_block(struct buffer_head *bh) 158 { 159 int error; 160 161 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 162 BHDR(bh)->h_blocks != cpu_to_le32(1)) 163 return -EIO; 164 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size); 165 return error; 166 } 167 168 static inline int 169 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size) 170 { 171 size_t value_size = le32_to_cpu(entry->e_value_size); 172 173 if (entry->e_value_block != 0 || value_size > size || 174 le16_to_cpu(entry->e_value_offs) + value_size > size) 175 return -EIO; 176 return 0; 177 } 178 179 static int 180 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index, 181 const char *name, size_t size, int sorted) 182 { 183 struct ext4_xattr_entry *entry; 184 size_t name_len; 185 int cmp = 1; 186 187 if (name == NULL) 188 return -EINVAL; 189 name_len = strlen(name); 190 entry = *pentry; 191 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 192 cmp = name_index - entry->e_name_index; 193 if (!cmp) 194 cmp = name_len - entry->e_name_len; 195 if (!cmp) 196 cmp = memcmp(name, entry->e_name, name_len); 197 if (cmp <= 0 && (sorted || cmp == 0)) 198 break; 199 } 200 *pentry = entry; 201 if (!cmp && ext4_xattr_check_entry(entry, size)) 202 return -EIO; 203 return cmp ? -ENODATA : 0; 204 } 205 206 static int 207 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name, 208 void *buffer, size_t buffer_size) 209 { 210 struct buffer_head *bh = NULL; 211 struct ext4_xattr_entry *entry; 212 size_t size; 213 int error; 214 215 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", 216 name_index, name, buffer, (long)buffer_size); 217 218 error = -ENODATA; 219 if (!EXT4_I(inode)->i_file_acl) 220 goto cleanup; 221 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl); 222 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 223 if (!bh) 224 goto cleanup; 225 ea_bdebug(bh, "b_count=%d, refcount=%d", 226 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 227 if (ext4_xattr_check_block(bh)) { 228 bad_block: ext4_error(inode->i_sb, __FUNCTION__, 229 "inode %lu: bad block %llu", inode->i_ino, 230 EXT4_I(inode)->i_file_acl); 231 error = -EIO; 232 goto cleanup; 233 } 234 ext4_xattr_cache_insert(bh); 235 entry = BFIRST(bh); 236 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1); 237 if (error == -EIO) 238 goto bad_block; 239 if (error) 240 goto cleanup; 241 size = le32_to_cpu(entry->e_value_size); 242 if (buffer) { 243 error = -ERANGE; 244 if (size > buffer_size) 245 goto cleanup; 246 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), 247 size); 248 } 249 error = size; 250 251 cleanup: 252 brelse(bh); 253 return error; 254 } 255 256 static int 257 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name, 258 void *buffer, size_t buffer_size) 259 { 260 struct ext4_xattr_ibody_header *header; 261 struct ext4_xattr_entry *entry; 262 struct ext4_inode *raw_inode; 263 struct ext4_iloc iloc; 264 size_t size; 265 void *end; 266 int error; 267 268 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR)) 269 return -ENODATA; 270 error = ext4_get_inode_loc(inode, &iloc); 271 if (error) 272 return error; 273 raw_inode = ext4_raw_inode(&iloc); 274 header = IHDR(inode, raw_inode); 275 entry = IFIRST(header); 276 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 277 error = ext4_xattr_check_names(entry, end); 278 if (error) 279 goto cleanup; 280 error = ext4_xattr_find_entry(&entry, name_index, name, 281 end - (void *)entry, 0); 282 if (error) 283 goto cleanup; 284 size = le32_to_cpu(entry->e_value_size); 285 if (buffer) { 286 error = -ERANGE; 287 if (size > buffer_size) 288 goto cleanup; 289 memcpy(buffer, (void *)IFIRST(header) + 290 le16_to_cpu(entry->e_value_offs), size); 291 } 292 error = size; 293 294 cleanup: 295 brelse(iloc.bh); 296 return error; 297 } 298 299 /* 300 * ext4_xattr_get() 301 * 302 * Copy an extended attribute into the buffer 303 * provided, or compute the buffer size required. 304 * Buffer is NULL to compute the size of the buffer required. 305 * 306 * Returns a negative error number on failure, or the number of bytes 307 * used / required on success. 308 */ 309 int 310 ext4_xattr_get(struct inode *inode, int name_index, const char *name, 311 void *buffer, size_t buffer_size) 312 { 313 int error; 314 315 down_read(&EXT4_I(inode)->xattr_sem); 316 error = ext4_xattr_ibody_get(inode, name_index, name, buffer, 317 buffer_size); 318 if (error == -ENODATA) 319 error = ext4_xattr_block_get(inode, name_index, name, buffer, 320 buffer_size); 321 up_read(&EXT4_I(inode)->xattr_sem); 322 return error; 323 } 324 325 static int 326 ext4_xattr_list_entries(struct inode *inode, struct ext4_xattr_entry *entry, 327 char *buffer, size_t buffer_size) 328 { 329 size_t rest = buffer_size; 330 331 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 332 struct xattr_handler *handler = 333 ext4_xattr_handler(entry->e_name_index); 334 335 if (handler) { 336 size_t size = handler->list(inode, buffer, rest, 337 entry->e_name, 338 entry->e_name_len); 339 if (buffer) { 340 if (size > rest) 341 return -ERANGE; 342 buffer += size; 343 } 344 rest -= size; 345 } 346 } 347 return buffer_size - rest; 348 } 349 350 static int 351 ext4_xattr_block_list(struct inode *inode, char *buffer, size_t buffer_size) 352 { 353 struct buffer_head *bh = NULL; 354 int error; 355 356 ea_idebug(inode, "buffer=%p, buffer_size=%ld", 357 buffer, (long)buffer_size); 358 359 error = 0; 360 if (!EXT4_I(inode)->i_file_acl) 361 goto cleanup; 362 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl); 363 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 364 error = -EIO; 365 if (!bh) 366 goto cleanup; 367 ea_bdebug(bh, "b_count=%d, refcount=%d", 368 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 369 if (ext4_xattr_check_block(bh)) { 370 ext4_error(inode->i_sb, __FUNCTION__, 371 "inode %lu: bad block %llu", inode->i_ino, 372 EXT4_I(inode)->i_file_acl); 373 error = -EIO; 374 goto cleanup; 375 } 376 ext4_xattr_cache_insert(bh); 377 error = ext4_xattr_list_entries(inode, BFIRST(bh), buffer, buffer_size); 378 379 cleanup: 380 brelse(bh); 381 382 return error; 383 } 384 385 static int 386 ext4_xattr_ibody_list(struct inode *inode, char *buffer, size_t buffer_size) 387 { 388 struct ext4_xattr_ibody_header *header; 389 struct ext4_inode *raw_inode; 390 struct ext4_iloc iloc; 391 void *end; 392 int error; 393 394 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR)) 395 return 0; 396 error = ext4_get_inode_loc(inode, &iloc); 397 if (error) 398 return error; 399 raw_inode = ext4_raw_inode(&iloc); 400 header = IHDR(inode, raw_inode); 401 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 402 error = ext4_xattr_check_names(IFIRST(header), end); 403 if (error) 404 goto cleanup; 405 error = ext4_xattr_list_entries(inode, IFIRST(header), 406 buffer, buffer_size); 407 408 cleanup: 409 brelse(iloc.bh); 410 return error; 411 } 412 413 /* 414 * ext4_xattr_list() 415 * 416 * Copy a list of attribute names into the buffer 417 * provided, or compute the buffer size required. 418 * Buffer is NULL to compute the size of the buffer required. 419 * 420 * Returns a negative error number on failure, or the number of bytes 421 * used / required on success. 422 */ 423 int 424 ext4_xattr_list(struct inode *inode, char *buffer, size_t buffer_size) 425 { 426 int i_error, b_error; 427 428 down_read(&EXT4_I(inode)->xattr_sem); 429 i_error = ext4_xattr_ibody_list(inode, buffer, buffer_size); 430 if (i_error < 0) { 431 b_error = 0; 432 } else { 433 if (buffer) { 434 buffer += i_error; 435 buffer_size -= i_error; 436 } 437 b_error = ext4_xattr_block_list(inode, buffer, buffer_size); 438 if (b_error < 0) 439 i_error = 0; 440 } 441 up_read(&EXT4_I(inode)->xattr_sem); 442 return i_error + b_error; 443 } 444 445 /* 446 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is 447 * not set, set it. 448 */ 449 static void ext4_xattr_update_super_block(handle_t *handle, 450 struct super_block *sb) 451 { 452 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR)) 453 return; 454 455 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) { 456 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR); 457 sb->s_dirt = 1; 458 ext4_journal_dirty_metadata(handle, EXT4_SB(sb)->s_sbh); 459 } 460 } 461 462 /* 463 * Release the xattr block BH: If the reference count is > 1, decrement 464 * it; otherwise free the block. 465 */ 466 static void 467 ext4_xattr_release_block(handle_t *handle, struct inode *inode, 468 struct buffer_head *bh) 469 { 470 struct mb_cache_entry *ce = NULL; 471 int error = 0; 472 473 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr); 474 error = ext4_journal_get_write_access(handle, bh); 475 if (error) 476 goto out; 477 478 lock_buffer(bh); 479 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) { 480 ea_bdebug(bh, "refcount now=0; freeing"); 481 if (ce) 482 mb_cache_entry_free(ce); 483 ext4_free_blocks(handle, inode, bh->b_blocknr, 1); 484 get_bh(bh); 485 ext4_forget(handle, 1, inode, bh, bh->b_blocknr); 486 } else { 487 BHDR(bh)->h_refcount = cpu_to_le32( 488 le32_to_cpu(BHDR(bh)->h_refcount) - 1); 489 error = ext4_journal_dirty_metadata(handle, bh); 490 if (IS_SYNC(inode)) 491 handle->h_sync = 1; 492 DQUOT_FREE_BLOCK(inode, 1); 493 ea_bdebug(bh, "refcount now=%d; releasing", 494 le32_to_cpu(BHDR(bh)->h_refcount)); 495 if (ce) 496 mb_cache_entry_release(ce); 497 } 498 unlock_buffer(bh); 499 out: 500 ext4_std_error(inode->i_sb, error); 501 return; 502 } 503 504 /* 505 * Find the available free space for EAs. This also returns the total number of 506 * bytes used by EA entries. 507 */ 508 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last, 509 size_t *min_offs, void *base, int *total) 510 { 511 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 512 *total += EXT4_XATTR_LEN(last->e_name_len); 513 if (!last->e_value_block && last->e_value_size) { 514 size_t offs = le16_to_cpu(last->e_value_offs); 515 if (offs < *min_offs) 516 *min_offs = offs; 517 } 518 } 519 return (*min_offs - ((void *)last - base) - sizeof(__u32)); 520 } 521 522 struct ext4_xattr_info { 523 int name_index; 524 const char *name; 525 const void *value; 526 size_t value_len; 527 }; 528 529 struct ext4_xattr_search { 530 struct ext4_xattr_entry *first; 531 void *base; 532 void *end; 533 struct ext4_xattr_entry *here; 534 int not_found; 535 }; 536 537 static int 538 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s) 539 { 540 struct ext4_xattr_entry *last; 541 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name); 542 543 /* Compute min_offs and last. */ 544 last = s->first; 545 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 546 if (!last->e_value_block && last->e_value_size) { 547 size_t offs = le16_to_cpu(last->e_value_offs); 548 if (offs < min_offs) 549 min_offs = offs; 550 } 551 } 552 free = min_offs - ((void *)last - s->base) - sizeof(__u32); 553 if (!s->not_found) { 554 if (!s->here->e_value_block && s->here->e_value_size) { 555 size_t size = le32_to_cpu(s->here->e_value_size); 556 free += EXT4_XATTR_SIZE(size); 557 } 558 free += EXT4_XATTR_LEN(name_len); 559 } 560 if (i->value) { 561 if (free < EXT4_XATTR_SIZE(i->value_len) || 562 free < EXT4_XATTR_LEN(name_len) + 563 EXT4_XATTR_SIZE(i->value_len)) 564 return -ENOSPC; 565 } 566 567 if (i->value && s->not_found) { 568 /* Insert the new name. */ 569 size_t size = EXT4_XATTR_LEN(name_len); 570 size_t rest = (void *)last - (void *)s->here + sizeof(__u32); 571 memmove((void *)s->here + size, s->here, rest); 572 memset(s->here, 0, size); 573 s->here->e_name_index = i->name_index; 574 s->here->e_name_len = name_len; 575 memcpy(s->here->e_name, i->name, name_len); 576 } else { 577 if (!s->here->e_value_block && s->here->e_value_size) { 578 void *first_val = s->base + min_offs; 579 size_t offs = le16_to_cpu(s->here->e_value_offs); 580 void *val = s->base + offs; 581 size_t size = EXT4_XATTR_SIZE( 582 le32_to_cpu(s->here->e_value_size)); 583 584 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) { 585 /* The old and the new value have the same 586 size. Just replace. */ 587 s->here->e_value_size = 588 cpu_to_le32(i->value_len); 589 memset(val + size - EXT4_XATTR_PAD, 0, 590 EXT4_XATTR_PAD); /* Clear pad bytes. */ 591 memcpy(val, i->value, i->value_len); 592 return 0; 593 } 594 595 /* Remove the old value. */ 596 memmove(first_val + size, first_val, val - first_val); 597 memset(first_val, 0, size); 598 s->here->e_value_size = 0; 599 s->here->e_value_offs = 0; 600 min_offs += size; 601 602 /* Adjust all value offsets. */ 603 last = s->first; 604 while (!IS_LAST_ENTRY(last)) { 605 size_t o = le16_to_cpu(last->e_value_offs); 606 if (!last->e_value_block && 607 last->e_value_size && o < offs) 608 last->e_value_offs = 609 cpu_to_le16(o + size); 610 last = EXT4_XATTR_NEXT(last); 611 } 612 } 613 if (!i->value) { 614 /* Remove the old name. */ 615 size_t size = EXT4_XATTR_LEN(name_len); 616 last = ENTRY((void *)last - size); 617 memmove(s->here, (void *)s->here + size, 618 (void *)last - (void *)s->here + sizeof(__u32)); 619 memset(last, 0, size); 620 } 621 } 622 623 if (i->value) { 624 /* Insert the new value. */ 625 s->here->e_value_size = cpu_to_le32(i->value_len); 626 if (i->value_len) { 627 size_t size = EXT4_XATTR_SIZE(i->value_len); 628 void *val = s->base + min_offs - size; 629 s->here->e_value_offs = cpu_to_le16(min_offs - size); 630 memset(val + size - EXT4_XATTR_PAD, 0, 631 EXT4_XATTR_PAD); /* Clear the pad bytes. */ 632 memcpy(val, i->value, i->value_len); 633 } 634 } 635 return 0; 636 } 637 638 struct ext4_xattr_block_find { 639 struct ext4_xattr_search s; 640 struct buffer_head *bh; 641 }; 642 643 static int 644 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i, 645 struct ext4_xattr_block_find *bs) 646 { 647 struct super_block *sb = inode->i_sb; 648 int error; 649 650 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", 651 i->name_index, i->name, i->value, (long)i->value_len); 652 653 if (EXT4_I(inode)->i_file_acl) { 654 /* The inode already has an extended attribute block. */ 655 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl); 656 error = -EIO; 657 if (!bs->bh) 658 goto cleanup; 659 ea_bdebug(bs->bh, "b_count=%d, refcount=%d", 660 atomic_read(&(bs->bh->b_count)), 661 le32_to_cpu(BHDR(bs->bh)->h_refcount)); 662 if (ext4_xattr_check_block(bs->bh)) { 663 ext4_error(sb, __FUNCTION__, 664 "inode %lu: bad block %llu", inode->i_ino, 665 EXT4_I(inode)->i_file_acl); 666 error = -EIO; 667 goto cleanup; 668 } 669 /* Find the named attribute. */ 670 bs->s.base = BHDR(bs->bh); 671 bs->s.first = BFIRST(bs->bh); 672 bs->s.end = bs->bh->b_data + bs->bh->b_size; 673 bs->s.here = bs->s.first; 674 error = ext4_xattr_find_entry(&bs->s.here, i->name_index, 675 i->name, bs->bh->b_size, 1); 676 if (error && error != -ENODATA) 677 goto cleanup; 678 bs->s.not_found = error; 679 } 680 error = 0; 681 682 cleanup: 683 return error; 684 } 685 686 static int 687 ext4_xattr_block_set(handle_t *handle, struct inode *inode, 688 struct ext4_xattr_info *i, 689 struct ext4_xattr_block_find *bs) 690 { 691 struct super_block *sb = inode->i_sb; 692 struct buffer_head *new_bh = NULL; 693 struct ext4_xattr_search *s = &bs->s; 694 struct mb_cache_entry *ce = NULL; 695 int error = 0; 696 697 #define header(x) ((struct ext4_xattr_header *)(x)) 698 699 if (i->value && i->value_len > sb->s_blocksize) 700 return -ENOSPC; 701 if (s->base) { 702 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev, 703 bs->bh->b_blocknr); 704 error = ext4_journal_get_write_access(handle, bs->bh); 705 if (error) 706 goto cleanup; 707 lock_buffer(bs->bh); 708 709 if (header(s->base)->h_refcount == cpu_to_le32(1)) { 710 if (ce) { 711 mb_cache_entry_free(ce); 712 ce = NULL; 713 } 714 ea_bdebug(bs->bh, "modifying in-place"); 715 error = ext4_xattr_set_entry(i, s); 716 if (!error) { 717 if (!IS_LAST_ENTRY(s->first)) 718 ext4_xattr_rehash(header(s->base), 719 s->here); 720 ext4_xattr_cache_insert(bs->bh); 721 } 722 unlock_buffer(bs->bh); 723 if (error == -EIO) 724 goto bad_block; 725 if (!error) 726 error = ext4_journal_dirty_metadata(handle, 727 bs->bh); 728 if (error) 729 goto cleanup; 730 goto inserted; 731 } else { 732 int offset = (char *)s->here - bs->bh->b_data; 733 734 unlock_buffer(bs->bh); 735 jbd2_journal_release_buffer(handle, bs->bh); 736 if (ce) { 737 mb_cache_entry_release(ce); 738 ce = NULL; 739 } 740 ea_bdebug(bs->bh, "cloning"); 741 s->base = kmalloc(bs->bh->b_size, GFP_KERNEL); 742 error = -ENOMEM; 743 if (s->base == NULL) 744 goto cleanup; 745 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size); 746 s->first = ENTRY(header(s->base)+1); 747 header(s->base)->h_refcount = cpu_to_le32(1); 748 s->here = ENTRY(s->base + offset); 749 s->end = s->base + bs->bh->b_size; 750 } 751 } else { 752 /* Allocate a buffer where we construct the new block. */ 753 s->base = kmalloc(sb->s_blocksize, GFP_KERNEL); 754 /* assert(header == s->base) */ 755 error = -ENOMEM; 756 if (s->base == NULL) 757 goto cleanup; 758 memset(s->base, 0, sb->s_blocksize); 759 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 760 header(s->base)->h_blocks = cpu_to_le32(1); 761 header(s->base)->h_refcount = cpu_to_le32(1); 762 s->first = ENTRY(header(s->base)+1); 763 s->here = ENTRY(header(s->base)+1); 764 s->end = s->base + sb->s_blocksize; 765 } 766 767 error = ext4_xattr_set_entry(i, s); 768 if (error == -EIO) 769 goto bad_block; 770 if (error) 771 goto cleanup; 772 if (!IS_LAST_ENTRY(s->first)) 773 ext4_xattr_rehash(header(s->base), s->here); 774 775 inserted: 776 if (!IS_LAST_ENTRY(s->first)) { 777 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce); 778 if (new_bh) { 779 /* We found an identical block in the cache. */ 780 if (new_bh == bs->bh) 781 ea_bdebug(new_bh, "keeping"); 782 else { 783 /* The old block is released after updating 784 the inode. */ 785 error = -EDQUOT; 786 if (DQUOT_ALLOC_BLOCK(inode, 1)) 787 goto cleanup; 788 error = ext4_journal_get_write_access(handle, 789 new_bh); 790 if (error) 791 goto cleanup_dquot; 792 lock_buffer(new_bh); 793 BHDR(new_bh)->h_refcount = cpu_to_le32(1 + 794 le32_to_cpu(BHDR(new_bh)->h_refcount)); 795 ea_bdebug(new_bh, "reusing; refcount now=%d", 796 le32_to_cpu(BHDR(new_bh)->h_refcount)); 797 unlock_buffer(new_bh); 798 error = ext4_journal_dirty_metadata(handle, 799 new_bh); 800 if (error) 801 goto cleanup_dquot; 802 } 803 mb_cache_entry_release(ce); 804 ce = NULL; 805 } else if (bs->bh && s->base == bs->bh->b_data) { 806 /* We were modifying this block in-place. */ 807 ea_bdebug(bs->bh, "keeping this block"); 808 new_bh = bs->bh; 809 get_bh(new_bh); 810 } else { 811 /* We need to allocate a new block */ 812 ext4_fsblk_t goal = le32_to_cpu( 813 EXT4_SB(sb)->s_es->s_first_data_block) + 814 (ext4_fsblk_t)EXT4_I(inode)->i_block_group * 815 EXT4_BLOCKS_PER_GROUP(sb); 816 ext4_fsblk_t block = ext4_new_block(handle, inode, 817 goal, &error); 818 if (error) 819 goto cleanup; 820 ea_idebug(inode, "creating block %d", block); 821 822 new_bh = sb_getblk(sb, block); 823 if (!new_bh) { 824 getblk_failed: 825 ext4_free_blocks(handle, inode, block, 1); 826 error = -EIO; 827 goto cleanup; 828 } 829 lock_buffer(new_bh); 830 error = ext4_journal_get_create_access(handle, new_bh); 831 if (error) { 832 unlock_buffer(new_bh); 833 goto getblk_failed; 834 } 835 memcpy(new_bh->b_data, s->base, new_bh->b_size); 836 set_buffer_uptodate(new_bh); 837 unlock_buffer(new_bh); 838 ext4_xattr_cache_insert(new_bh); 839 error = ext4_journal_dirty_metadata(handle, new_bh); 840 if (error) 841 goto cleanup; 842 } 843 } 844 845 /* Update the inode. */ 846 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; 847 848 /* Drop the previous xattr block. */ 849 if (bs->bh && bs->bh != new_bh) 850 ext4_xattr_release_block(handle, inode, bs->bh); 851 error = 0; 852 853 cleanup: 854 if (ce) 855 mb_cache_entry_release(ce); 856 brelse(new_bh); 857 if (!(bs->bh && s->base == bs->bh->b_data)) 858 kfree(s->base); 859 860 return error; 861 862 cleanup_dquot: 863 DQUOT_FREE_BLOCK(inode, 1); 864 goto cleanup; 865 866 bad_block: 867 ext4_error(inode->i_sb, __FUNCTION__, 868 "inode %lu: bad block %llu", inode->i_ino, 869 EXT4_I(inode)->i_file_acl); 870 goto cleanup; 871 872 #undef header 873 } 874 875 struct ext4_xattr_ibody_find { 876 struct ext4_xattr_search s; 877 struct ext4_iloc iloc; 878 }; 879 880 static int 881 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, 882 struct ext4_xattr_ibody_find *is) 883 { 884 struct ext4_xattr_ibody_header *header; 885 struct ext4_inode *raw_inode; 886 int error; 887 888 if (EXT4_I(inode)->i_extra_isize == 0) 889 return 0; 890 raw_inode = ext4_raw_inode(&is->iloc); 891 header = IHDR(inode, raw_inode); 892 is->s.base = is->s.first = IFIRST(header); 893 is->s.here = is->s.first; 894 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 895 if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) { 896 error = ext4_xattr_check_names(IFIRST(header), is->s.end); 897 if (error) 898 return error; 899 /* Find the named attribute. */ 900 error = ext4_xattr_find_entry(&is->s.here, i->name_index, 901 i->name, is->s.end - 902 (void *)is->s.base, 0); 903 if (error && error != -ENODATA) 904 return error; 905 is->s.not_found = error; 906 } 907 return 0; 908 } 909 910 static int 911 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode, 912 struct ext4_xattr_info *i, 913 struct ext4_xattr_ibody_find *is) 914 { 915 struct ext4_xattr_ibody_header *header; 916 struct ext4_xattr_search *s = &is->s; 917 int error; 918 919 if (EXT4_I(inode)->i_extra_isize == 0) 920 return -ENOSPC; 921 error = ext4_xattr_set_entry(i, s); 922 if (error) 923 return error; 924 header = IHDR(inode, ext4_raw_inode(&is->iloc)); 925 if (!IS_LAST_ENTRY(s->first)) { 926 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 927 EXT4_I(inode)->i_state |= EXT4_STATE_XATTR; 928 } else { 929 header->h_magic = cpu_to_le32(0); 930 EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR; 931 } 932 return 0; 933 } 934 935 /* 936 * ext4_xattr_set_handle() 937 * 938 * Create, replace or remove an extended attribute for this inode. Buffer 939 * is NULL to remove an existing extended attribute, and non-NULL to 940 * either replace an existing extended attribute, or create a new extended 941 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 942 * specify that an extended attribute must exist and must not exist 943 * previous to the call, respectively. 944 * 945 * Returns 0, or a negative error number on failure. 946 */ 947 int 948 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, 949 const char *name, const void *value, size_t value_len, 950 int flags) 951 { 952 struct ext4_xattr_info i = { 953 .name_index = name_index, 954 .name = name, 955 .value = value, 956 .value_len = value_len, 957 958 }; 959 struct ext4_xattr_ibody_find is = { 960 .s = { .not_found = -ENODATA, }, 961 }; 962 struct ext4_xattr_block_find bs = { 963 .s = { .not_found = -ENODATA, }, 964 }; 965 int error; 966 967 if (!name) 968 return -EINVAL; 969 if (strlen(name) > 255) 970 return -ERANGE; 971 down_write(&EXT4_I(inode)->xattr_sem); 972 error = ext4_get_inode_loc(inode, &is.iloc); 973 if (error) 974 goto cleanup; 975 976 if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) { 977 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc); 978 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); 979 EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW; 980 } 981 982 error = ext4_xattr_ibody_find(inode, &i, &is); 983 if (error) 984 goto cleanup; 985 if (is.s.not_found) 986 error = ext4_xattr_block_find(inode, &i, &bs); 987 if (error) 988 goto cleanup; 989 if (is.s.not_found && bs.s.not_found) { 990 error = -ENODATA; 991 if (flags & XATTR_REPLACE) 992 goto cleanup; 993 error = 0; 994 if (!value) 995 goto cleanup; 996 } else { 997 error = -EEXIST; 998 if (flags & XATTR_CREATE) 999 goto cleanup; 1000 } 1001 error = ext4_journal_get_write_access(handle, is.iloc.bh); 1002 if (error) 1003 goto cleanup; 1004 if (!value) { 1005 if (!is.s.not_found) 1006 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1007 else if (!bs.s.not_found) 1008 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1009 } else { 1010 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1011 if (!error && !bs.s.not_found) { 1012 i.value = NULL; 1013 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1014 } else if (error == -ENOSPC) { 1015 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1016 if (error) 1017 goto cleanup; 1018 if (!is.s.not_found) { 1019 i.value = NULL; 1020 error = ext4_xattr_ibody_set(handle, inode, &i, 1021 &is); 1022 } 1023 } 1024 } 1025 if (!error) { 1026 ext4_xattr_update_super_block(handle, inode->i_sb); 1027 inode->i_ctime = ext4_current_time(inode); 1028 if (!value) 1029 EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND; 1030 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc); 1031 /* 1032 * The bh is consumed by ext4_mark_iloc_dirty, even with 1033 * error != 0. 1034 */ 1035 is.iloc.bh = NULL; 1036 if (IS_SYNC(inode)) 1037 handle->h_sync = 1; 1038 } 1039 1040 cleanup: 1041 brelse(is.iloc.bh); 1042 brelse(bs.bh); 1043 up_write(&EXT4_I(inode)->xattr_sem); 1044 return error; 1045 } 1046 1047 /* 1048 * ext4_xattr_set() 1049 * 1050 * Like ext4_xattr_set_handle, but start from an inode. This extended 1051 * attribute modification is a filesystem transaction by itself. 1052 * 1053 * Returns 0, or a negative error number on failure. 1054 */ 1055 int 1056 ext4_xattr_set(struct inode *inode, int name_index, const char *name, 1057 const void *value, size_t value_len, int flags) 1058 { 1059 handle_t *handle; 1060 int error, retries = 0; 1061 1062 retry: 1063 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb)); 1064 if (IS_ERR(handle)) { 1065 error = PTR_ERR(handle); 1066 } else { 1067 int error2; 1068 1069 error = ext4_xattr_set_handle(handle, inode, name_index, name, 1070 value, value_len, flags); 1071 error2 = ext4_journal_stop(handle); 1072 if (error == -ENOSPC && 1073 ext4_should_retry_alloc(inode->i_sb, &retries)) 1074 goto retry; 1075 if (error == 0) 1076 error = error2; 1077 } 1078 1079 return error; 1080 } 1081 1082 /* 1083 * Shift the EA entries in the inode to create space for the increased 1084 * i_extra_isize. 1085 */ 1086 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry, 1087 int value_offs_shift, void *to, 1088 void *from, size_t n, int blocksize) 1089 { 1090 struct ext4_xattr_entry *last = entry; 1091 int new_offs; 1092 1093 /* Adjust the value offsets of the entries */ 1094 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1095 if (!last->e_value_block && last->e_value_size) { 1096 new_offs = le16_to_cpu(last->e_value_offs) + 1097 value_offs_shift; 1098 BUG_ON(new_offs + le32_to_cpu(last->e_value_size) 1099 > blocksize); 1100 last->e_value_offs = cpu_to_le16(new_offs); 1101 } 1102 } 1103 /* Shift the entries by n bytes */ 1104 memmove(to, from, n); 1105 } 1106 1107 /* 1108 * Expand an inode by new_extra_isize bytes when EAs are present. 1109 * Returns 0 on success or negative error number on failure. 1110 */ 1111 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, 1112 struct ext4_inode *raw_inode, handle_t *handle) 1113 { 1114 struct ext4_xattr_ibody_header *header; 1115 struct ext4_xattr_entry *entry, *last, *first; 1116 struct buffer_head *bh = NULL; 1117 struct ext4_xattr_ibody_find *is = NULL; 1118 struct ext4_xattr_block_find *bs = NULL; 1119 char *buffer = NULL, *b_entry_name = NULL; 1120 size_t min_offs, free; 1121 int total_ino, total_blk; 1122 void *base, *start, *end; 1123 int extra_isize = 0, error = 0, tried_min_extra_isize = 0; 1124 int s_min_extra_isize = EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize; 1125 1126 down_write(&EXT4_I(inode)->xattr_sem); 1127 retry: 1128 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) { 1129 up_write(&EXT4_I(inode)->xattr_sem); 1130 return 0; 1131 } 1132 1133 header = IHDR(inode, raw_inode); 1134 entry = IFIRST(header); 1135 1136 /* 1137 * Check if enough free space is available in the inode to shift the 1138 * entries ahead by new_extra_isize. 1139 */ 1140 1141 base = start = entry; 1142 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 1143 min_offs = end - base; 1144 last = entry; 1145 total_ino = sizeof(struct ext4_xattr_ibody_header); 1146 1147 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino); 1148 if (free >= new_extra_isize) { 1149 entry = IFIRST(header); 1150 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize 1151 - new_extra_isize, (void *)raw_inode + 1152 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize, 1153 (void *)header, total_ino, 1154 inode->i_sb->s_blocksize); 1155 EXT4_I(inode)->i_extra_isize = new_extra_isize; 1156 error = 0; 1157 goto cleanup; 1158 } 1159 1160 /* 1161 * Enough free space isn't available in the inode, check if 1162 * EA block can hold new_extra_isize bytes. 1163 */ 1164 if (EXT4_I(inode)->i_file_acl) { 1165 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1166 error = -EIO; 1167 if (!bh) 1168 goto cleanup; 1169 if (ext4_xattr_check_block(bh)) { 1170 ext4_error(inode->i_sb, __FUNCTION__, 1171 "inode %lu: bad block %llu", inode->i_ino, 1172 EXT4_I(inode)->i_file_acl); 1173 error = -EIO; 1174 goto cleanup; 1175 } 1176 base = BHDR(bh); 1177 first = BFIRST(bh); 1178 end = bh->b_data + bh->b_size; 1179 min_offs = end - base; 1180 free = ext4_xattr_free_space(first, &min_offs, base, 1181 &total_blk); 1182 if (free < new_extra_isize) { 1183 if (!tried_min_extra_isize && s_min_extra_isize) { 1184 tried_min_extra_isize++; 1185 new_extra_isize = s_min_extra_isize; 1186 brelse(bh); 1187 goto retry; 1188 } 1189 error = -1; 1190 goto cleanup; 1191 } 1192 } else { 1193 free = inode->i_sb->s_blocksize; 1194 } 1195 1196 while (new_extra_isize > 0) { 1197 size_t offs, size, entry_size; 1198 struct ext4_xattr_entry *small_entry = NULL; 1199 struct ext4_xattr_info i = { 1200 .value = NULL, 1201 .value_len = 0, 1202 }; 1203 unsigned int total_size; /* EA entry size + value size */ 1204 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */ 1205 unsigned int min_total_size = ~0U; 1206 1207 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS); 1208 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS); 1209 if (!is || !bs) { 1210 error = -ENOMEM; 1211 goto cleanup; 1212 } 1213 1214 is->s.not_found = -ENODATA; 1215 bs->s.not_found = -ENODATA; 1216 is->iloc.bh = NULL; 1217 bs->bh = NULL; 1218 1219 last = IFIRST(header); 1220 /* Find the entry best suited to be pushed into EA block */ 1221 entry = NULL; 1222 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1223 total_size = 1224 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) + 1225 EXT4_XATTR_LEN(last->e_name_len); 1226 if (total_size <= free && total_size < min_total_size) { 1227 if (total_size < new_extra_isize) { 1228 small_entry = last; 1229 } else { 1230 entry = last; 1231 min_total_size = total_size; 1232 } 1233 } 1234 } 1235 1236 if (entry == NULL) { 1237 if (small_entry) { 1238 entry = small_entry; 1239 } else { 1240 if (!tried_min_extra_isize && 1241 s_min_extra_isize) { 1242 tried_min_extra_isize++; 1243 new_extra_isize = s_min_extra_isize; 1244 goto retry; 1245 } 1246 error = -1; 1247 goto cleanup; 1248 } 1249 } 1250 offs = le16_to_cpu(entry->e_value_offs); 1251 size = le32_to_cpu(entry->e_value_size); 1252 entry_size = EXT4_XATTR_LEN(entry->e_name_len); 1253 i.name_index = entry->e_name_index, 1254 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS); 1255 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS); 1256 if (!buffer || !b_entry_name) { 1257 error = -ENOMEM; 1258 goto cleanup; 1259 } 1260 /* Save the entry name and the entry value */ 1261 memcpy(buffer, (void *)IFIRST(header) + offs, 1262 EXT4_XATTR_SIZE(size)); 1263 memcpy(b_entry_name, entry->e_name, entry->e_name_len); 1264 b_entry_name[entry->e_name_len] = '\0'; 1265 i.name = b_entry_name; 1266 1267 error = ext4_get_inode_loc(inode, &is->iloc); 1268 if (error) 1269 goto cleanup; 1270 1271 error = ext4_xattr_ibody_find(inode, &i, is); 1272 if (error) 1273 goto cleanup; 1274 1275 /* Remove the chosen entry from the inode */ 1276 error = ext4_xattr_ibody_set(handle, inode, &i, is); 1277 1278 entry = IFIRST(header); 1279 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize) 1280 shift_bytes = new_extra_isize; 1281 else 1282 shift_bytes = entry_size + size; 1283 /* Adjust the offsets and shift the remaining entries ahead */ 1284 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize - 1285 shift_bytes, (void *)raw_inode + 1286 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes, 1287 (void *)header, total_ino - entry_size, 1288 inode->i_sb->s_blocksize); 1289 1290 extra_isize += shift_bytes; 1291 new_extra_isize -= shift_bytes; 1292 EXT4_I(inode)->i_extra_isize = extra_isize; 1293 1294 i.name = b_entry_name; 1295 i.value = buffer; 1296 i.value_len = cpu_to_le32(size); 1297 error = ext4_xattr_block_find(inode, &i, bs); 1298 if (error) 1299 goto cleanup; 1300 1301 /* Add entry which was removed from the inode into the block */ 1302 error = ext4_xattr_block_set(handle, inode, &i, bs); 1303 if (error) 1304 goto cleanup; 1305 kfree(b_entry_name); 1306 kfree(buffer); 1307 brelse(is->iloc.bh); 1308 kfree(is); 1309 kfree(bs); 1310 } 1311 brelse(bh); 1312 up_write(&EXT4_I(inode)->xattr_sem); 1313 return 0; 1314 1315 cleanup: 1316 kfree(b_entry_name); 1317 kfree(buffer); 1318 if (is) 1319 brelse(is->iloc.bh); 1320 kfree(is); 1321 kfree(bs); 1322 brelse(bh); 1323 up_write(&EXT4_I(inode)->xattr_sem); 1324 return error; 1325 } 1326 1327 1328 1329 /* 1330 * ext4_xattr_delete_inode() 1331 * 1332 * Free extended attribute resources associated with this inode. This 1333 * is called immediately before an inode is freed. We have exclusive 1334 * access to the inode. 1335 */ 1336 void 1337 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode) 1338 { 1339 struct buffer_head *bh = NULL; 1340 1341 if (!EXT4_I(inode)->i_file_acl) 1342 goto cleanup; 1343 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1344 if (!bh) { 1345 ext4_error(inode->i_sb, __FUNCTION__, 1346 "inode %lu: block %llu read error", inode->i_ino, 1347 EXT4_I(inode)->i_file_acl); 1348 goto cleanup; 1349 } 1350 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 1351 BHDR(bh)->h_blocks != cpu_to_le32(1)) { 1352 ext4_error(inode->i_sb, __FUNCTION__, 1353 "inode %lu: bad block %llu", inode->i_ino, 1354 EXT4_I(inode)->i_file_acl); 1355 goto cleanup; 1356 } 1357 ext4_xattr_release_block(handle, inode, bh); 1358 EXT4_I(inode)->i_file_acl = 0; 1359 1360 cleanup: 1361 brelse(bh); 1362 } 1363 1364 /* 1365 * ext4_xattr_put_super() 1366 * 1367 * This is called when a file system is unmounted. 1368 */ 1369 void 1370 ext4_xattr_put_super(struct super_block *sb) 1371 { 1372 mb_cache_shrink(sb->s_bdev); 1373 } 1374 1375 /* 1376 * ext4_xattr_cache_insert() 1377 * 1378 * Create a new entry in the extended attribute cache, and insert 1379 * it unless such an entry is already in the cache. 1380 * 1381 * Returns 0, or a negative error number on failure. 1382 */ 1383 static void 1384 ext4_xattr_cache_insert(struct buffer_head *bh) 1385 { 1386 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash); 1387 struct mb_cache_entry *ce; 1388 int error; 1389 1390 ce = mb_cache_entry_alloc(ext4_xattr_cache); 1391 if (!ce) { 1392 ea_bdebug(bh, "out of memory"); 1393 return; 1394 } 1395 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash); 1396 if (error) { 1397 mb_cache_entry_free(ce); 1398 if (error == -EBUSY) { 1399 ea_bdebug(bh, "already in cache"); 1400 error = 0; 1401 } 1402 } else { 1403 ea_bdebug(bh, "inserting [%x]", (int)hash); 1404 mb_cache_entry_release(ce); 1405 } 1406 } 1407 1408 /* 1409 * ext4_xattr_cmp() 1410 * 1411 * Compare two extended attribute blocks for equality. 1412 * 1413 * Returns 0 if the blocks are equal, 1 if they differ, and 1414 * a negative error number on errors. 1415 */ 1416 static int 1417 ext4_xattr_cmp(struct ext4_xattr_header *header1, 1418 struct ext4_xattr_header *header2) 1419 { 1420 struct ext4_xattr_entry *entry1, *entry2; 1421 1422 entry1 = ENTRY(header1+1); 1423 entry2 = ENTRY(header2+1); 1424 while (!IS_LAST_ENTRY(entry1)) { 1425 if (IS_LAST_ENTRY(entry2)) 1426 return 1; 1427 if (entry1->e_hash != entry2->e_hash || 1428 entry1->e_name_index != entry2->e_name_index || 1429 entry1->e_name_len != entry2->e_name_len || 1430 entry1->e_value_size != entry2->e_value_size || 1431 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) 1432 return 1; 1433 if (entry1->e_value_block != 0 || entry2->e_value_block != 0) 1434 return -EIO; 1435 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), 1436 (char *)header2 + le16_to_cpu(entry2->e_value_offs), 1437 le32_to_cpu(entry1->e_value_size))) 1438 return 1; 1439 1440 entry1 = EXT4_XATTR_NEXT(entry1); 1441 entry2 = EXT4_XATTR_NEXT(entry2); 1442 } 1443 if (!IS_LAST_ENTRY(entry2)) 1444 return 1; 1445 return 0; 1446 } 1447 1448 /* 1449 * ext4_xattr_cache_find() 1450 * 1451 * Find an identical extended attribute block. 1452 * 1453 * Returns a pointer to the block found, or NULL if such a block was 1454 * not found or an error occurred. 1455 */ 1456 static struct buffer_head * 1457 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header, 1458 struct mb_cache_entry **pce) 1459 { 1460 __u32 hash = le32_to_cpu(header->h_hash); 1461 struct mb_cache_entry *ce; 1462 1463 if (!header->h_hash) 1464 return NULL; /* never share */ 1465 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); 1466 again: 1467 ce = mb_cache_entry_find_first(ext4_xattr_cache, 0, 1468 inode->i_sb->s_bdev, hash); 1469 while (ce) { 1470 struct buffer_head *bh; 1471 1472 if (IS_ERR(ce)) { 1473 if (PTR_ERR(ce) == -EAGAIN) 1474 goto again; 1475 break; 1476 } 1477 bh = sb_bread(inode->i_sb, ce->e_block); 1478 if (!bh) { 1479 ext4_error(inode->i_sb, __FUNCTION__, 1480 "inode %lu: block %lu read error", 1481 inode->i_ino, (unsigned long) ce->e_block); 1482 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >= 1483 EXT4_XATTR_REFCOUNT_MAX) { 1484 ea_idebug(inode, "block %lu refcount %d>=%d", 1485 (unsigned long) ce->e_block, 1486 le32_to_cpu(BHDR(bh)->h_refcount), 1487 EXT4_XATTR_REFCOUNT_MAX); 1488 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) { 1489 *pce = ce; 1490 return bh; 1491 } 1492 brelse(bh); 1493 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash); 1494 } 1495 return NULL; 1496 } 1497 1498 #define NAME_HASH_SHIFT 5 1499 #define VALUE_HASH_SHIFT 16 1500 1501 /* 1502 * ext4_xattr_hash_entry() 1503 * 1504 * Compute the hash of an extended attribute. 1505 */ 1506 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header, 1507 struct ext4_xattr_entry *entry) 1508 { 1509 __u32 hash = 0; 1510 char *name = entry->e_name; 1511 int n; 1512 1513 for (n=0; n < entry->e_name_len; n++) { 1514 hash = (hash << NAME_HASH_SHIFT) ^ 1515 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ 1516 *name++; 1517 } 1518 1519 if (entry->e_value_block == 0 && entry->e_value_size != 0) { 1520 __le32 *value = (__le32 *)((char *)header + 1521 le16_to_cpu(entry->e_value_offs)); 1522 for (n = (le32_to_cpu(entry->e_value_size) + 1523 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) { 1524 hash = (hash << VALUE_HASH_SHIFT) ^ 1525 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ 1526 le32_to_cpu(*value++); 1527 } 1528 } 1529 entry->e_hash = cpu_to_le32(hash); 1530 } 1531 1532 #undef NAME_HASH_SHIFT 1533 #undef VALUE_HASH_SHIFT 1534 1535 #define BLOCK_HASH_SHIFT 16 1536 1537 /* 1538 * ext4_xattr_rehash() 1539 * 1540 * Re-compute the extended attribute hash value after an entry has changed. 1541 */ 1542 static void ext4_xattr_rehash(struct ext4_xattr_header *header, 1543 struct ext4_xattr_entry *entry) 1544 { 1545 struct ext4_xattr_entry *here; 1546 __u32 hash = 0; 1547 1548 ext4_xattr_hash_entry(header, entry); 1549 here = ENTRY(header+1); 1550 while (!IS_LAST_ENTRY(here)) { 1551 if (!here->e_hash) { 1552 /* Block is not shared if an entry's hash value == 0 */ 1553 hash = 0; 1554 break; 1555 } 1556 hash = (hash << BLOCK_HASH_SHIFT) ^ 1557 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ 1558 le32_to_cpu(here->e_hash); 1559 here = EXT4_XATTR_NEXT(here); 1560 } 1561 header->h_hash = cpu_to_le32(hash); 1562 } 1563 1564 #undef BLOCK_HASH_SHIFT 1565 1566 int __init 1567 init_ext4_xattr(void) 1568 { 1569 ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL, 1570 sizeof(struct mb_cache_entry) + 1571 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6); 1572 if (!ext4_xattr_cache) 1573 return -ENOMEM; 1574 return 0; 1575 } 1576 1577 void 1578 exit_ext4_xattr(void) 1579 { 1580 if (ext4_xattr_cache) 1581 mb_cache_destroy(ext4_xattr_cache); 1582 ext4_xattr_cache = NULL; 1583 } 1584