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/mbcache.h> 57 #include <linux/quotaops.h> 58 #include <linux/rwsem.h> 59 #include "ext4_jbd2.h" 60 #include "ext4.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 static int ext4_xattr_list(struct inode *inode, char *buffer, 96 size_t buffer_size); 97 98 static struct mb_cache *ext4_xattr_cache; 99 100 static struct xattr_handler *ext4_xattr_handler_map[] = { 101 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler, 102 #ifdef CONFIG_EXT4_FS_POSIX_ACL 103 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler, 104 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler, 105 #endif 106 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler, 107 #ifdef CONFIG_EXT4_FS_SECURITY 108 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler, 109 #endif 110 }; 111 112 struct xattr_handler *ext4_xattr_handlers[] = { 113 &ext4_xattr_user_handler, 114 &ext4_xattr_trusted_handler, 115 #ifdef CONFIG_EXT4_FS_POSIX_ACL 116 &ext4_xattr_acl_access_handler, 117 &ext4_xattr_acl_default_handler, 118 #endif 119 #ifdef CONFIG_EXT4_FS_SECURITY 120 &ext4_xattr_security_handler, 121 #endif 122 NULL 123 }; 124 125 static inline struct xattr_handler * 126 ext4_xattr_handler(int name_index) 127 { 128 struct xattr_handler *handler = NULL; 129 130 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map)) 131 handler = ext4_xattr_handler_map[name_index]; 132 return handler; 133 } 134 135 /* 136 * Inode operation listxattr() 137 * 138 * dentry->d_inode->i_mutex: don't care 139 */ 140 ssize_t 141 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size) 142 { 143 return ext4_xattr_list(dentry->d_inode, buffer, size); 144 } 145 146 static int 147 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end) 148 { 149 while (!IS_LAST_ENTRY(entry)) { 150 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry); 151 if ((void *)next >= end) 152 return -EIO; 153 entry = next; 154 } 155 return 0; 156 } 157 158 static inline int 159 ext4_xattr_check_block(struct buffer_head *bh) 160 { 161 int error; 162 163 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 164 BHDR(bh)->h_blocks != cpu_to_le32(1)) 165 return -EIO; 166 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size); 167 return error; 168 } 169 170 static inline int 171 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size) 172 { 173 size_t value_size = le32_to_cpu(entry->e_value_size); 174 175 if (entry->e_value_block != 0 || value_size > size || 176 le16_to_cpu(entry->e_value_offs) + value_size > size) 177 return -EIO; 178 return 0; 179 } 180 181 static int 182 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index, 183 const char *name, size_t size, int sorted) 184 { 185 struct ext4_xattr_entry *entry; 186 size_t name_len; 187 int cmp = 1; 188 189 if (name == NULL) 190 return -EINVAL; 191 name_len = strlen(name); 192 entry = *pentry; 193 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 194 cmp = name_index - entry->e_name_index; 195 if (!cmp) 196 cmp = name_len - entry->e_name_len; 197 if (!cmp) 198 cmp = memcmp(name, entry->e_name, name_len); 199 if (cmp <= 0 && (sorted || cmp == 0)) 200 break; 201 } 202 *pentry = entry; 203 if (!cmp && ext4_xattr_check_entry(entry, size)) 204 return -EIO; 205 return cmp ? -ENODATA : 0; 206 } 207 208 static int 209 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name, 210 void *buffer, size_t buffer_size) 211 { 212 struct buffer_head *bh = NULL; 213 struct ext4_xattr_entry *entry; 214 size_t size; 215 int error; 216 217 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", 218 name_index, name, buffer, (long)buffer_size); 219 220 error = -ENODATA; 221 if (!EXT4_I(inode)->i_file_acl) 222 goto cleanup; 223 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl); 224 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 225 if (!bh) 226 goto cleanup; 227 ea_bdebug(bh, "b_count=%d, refcount=%d", 228 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 229 if (ext4_xattr_check_block(bh)) { 230 bad_block: ext4_error(inode->i_sb, __func__, 231 "inode %lu: bad block %llu", inode->i_ino, 232 EXT4_I(inode)->i_file_acl); 233 error = -EIO; 234 goto cleanup; 235 } 236 ext4_xattr_cache_insert(bh); 237 entry = BFIRST(bh); 238 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1); 239 if (error == -EIO) 240 goto bad_block; 241 if (error) 242 goto cleanup; 243 size = le32_to_cpu(entry->e_value_size); 244 if (buffer) { 245 error = -ERANGE; 246 if (size > buffer_size) 247 goto cleanup; 248 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), 249 size); 250 } 251 error = size; 252 253 cleanup: 254 brelse(bh); 255 return error; 256 } 257 258 static int 259 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name, 260 void *buffer, size_t buffer_size) 261 { 262 struct ext4_xattr_ibody_header *header; 263 struct ext4_xattr_entry *entry; 264 struct ext4_inode *raw_inode; 265 struct ext4_iloc iloc; 266 size_t size; 267 void *end; 268 int error; 269 270 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR)) 271 return -ENODATA; 272 error = ext4_get_inode_loc(inode, &iloc); 273 if (error) 274 return error; 275 raw_inode = ext4_raw_inode(&iloc); 276 header = IHDR(inode, raw_inode); 277 entry = IFIRST(header); 278 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 279 error = ext4_xattr_check_names(entry, end); 280 if (error) 281 goto cleanup; 282 error = ext4_xattr_find_entry(&entry, name_index, name, 283 end - (void *)entry, 0); 284 if (error) 285 goto cleanup; 286 size = le32_to_cpu(entry->e_value_size); 287 if (buffer) { 288 error = -ERANGE; 289 if (size > buffer_size) 290 goto cleanup; 291 memcpy(buffer, (void *)IFIRST(header) + 292 le16_to_cpu(entry->e_value_offs), size); 293 } 294 error = size; 295 296 cleanup: 297 brelse(iloc.bh); 298 return error; 299 } 300 301 /* 302 * ext4_xattr_get() 303 * 304 * Copy an extended attribute into the buffer 305 * provided, or compute the buffer size required. 306 * Buffer is NULL to compute the size of the buffer required. 307 * 308 * Returns a negative error number on failure, or the number of bytes 309 * used / required on success. 310 */ 311 int 312 ext4_xattr_get(struct inode *inode, int name_index, const char *name, 313 void *buffer, size_t buffer_size) 314 { 315 int error; 316 317 down_read(&EXT4_I(inode)->xattr_sem); 318 error = ext4_xattr_ibody_get(inode, name_index, name, buffer, 319 buffer_size); 320 if (error == -ENODATA) 321 error = ext4_xattr_block_get(inode, name_index, name, buffer, 322 buffer_size); 323 up_read(&EXT4_I(inode)->xattr_sem); 324 return error; 325 } 326 327 static int 328 ext4_xattr_list_entries(struct inode *inode, struct ext4_xattr_entry *entry, 329 char *buffer, size_t buffer_size) 330 { 331 size_t rest = buffer_size; 332 333 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 334 struct xattr_handler *handler = 335 ext4_xattr_handler(entry->e_name_index); 336 337 if (handler) { 338 size_t size = handler->list(inode, buffer, rest, 339 entry->e_name, 340 entry->e_name_len); 341 if (buffer) { 342 if (size > rest) 343 return -ERANGE; 344 buffer += size; 345 } 346 rest -= size; 347 } 348 } 349 return buffer_size - rest; 350 } 351 352 static int 353 ext4_xattr_block_list(struct inode *inode, char *buffer, size_t buffer_size) 354 { 355 struct buffer_head *bh = NULL; 356 int error; 357 358 ea_idebug(inode, "buffer=%p, buffer_size=%ld", 359 buffer, (long)buffer_size); 360 361 error = 0; 362 if (!EXT4_I(inode)->i_file_acl) 363 goto cleanup; 364 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl); 365 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 366 error = -EIO; 367 if (!bh) 368 goto cleanup; 369 ea_bdebug(bh, "b_count=%d, refcount=%d", 370 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 371 if (ext4_xattr_check_block(bh)) { 372 ext4_error(inode->i_sb, __func__, 373 "inode %lu: bad block %llu", inode->i_ino, 374 EXT4_I(inode)->i_file_acl); 375 error = -EIO; 376 goto cleanup; 377 } 378 ext4_xattr_cache_insert(bh); 379 error = ext4_xattr_list_entries(inode, BFIRST(bh), buffer, buffer_size); 380 381 cleanup: 382 brelse(bh); 383 384 return error; 385 } 386 387 static int 388 ext4_xattr_ibody_list(struct inode *inode, char *buffer, size_t buffer_size) 389 { 390 struct ext4_xattr_ibody_header *header; 391 struct ext4_inode *raw_inode; 392 struct ext4_iloc iloc; 393 void *end; 394 int error; 395 396 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR)) 397 return 0; 398 error = ext4_get_inode_loc(inode, &iloc); 399 if (error) 400 return error; 401 raw_inode = ext4_raw_inode(&iloc); 402 header = IHDR(inode, raw_inode); 403 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 404 error = ext4_xattr_check_names(IFIRST(header), end); 405 if (error) 406 goto cleanup; 407 error = ext4_xattr_list_entries(inode, IFIRST(header), 408 buffer, buffer_size); 409 410 cleanup: 411 brelse(iloc.bh); 412 return error; 413 } 414 415 /* 416 * ext4_xattr_list() 417 * 418 * Copy a list of attribute names into the buffer 419 * provided, or compute the buffer size required. 420 * Buffer is NULL to compute the size of the buffer required. 421 * 422 * Returns a negative error number on failure, or the number of bytes 423 * used / required on success. 424 */ 425 static int 426 ext4_xattr_list(struct inode *inode, char *buffer, size_t buffer_size) 427 { 428 int i_error, b_error; 429 430 down_read(&EXT4_I(inode)->xattr_sem); 431 i_error = ext4_xattr_ibody_list(inode, buffer, buffer_size); 432 if (i_error < 0) { 433 b_error = 0; 434 } else { 435 if (buffer) { 436 buffer += i_error; 437 buffer_size -= i_error; 438 } 439 b_error = ext4_xattr_block_list(inode, buffer, buffer_size); 440 if (b_error < 0) 441 i_error = 0; 442 } 443 up_read(&EXT4_I(inode)->xattr_sem); 444 return i_error + b_error; 445 } 446 447 /* 448 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is 449 * not set, set it. 450 */ 451 static void ext4_xattr_update_super_block(handle_t *handle, 452 struct super_block *sb) 453 { 454 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR)) 455 return; 456 457 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) { 458 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR); 459 sb->s_dirt = 1; 460 ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh); 461 } 462 } 463 464 /* 465 * Release the xattr block BH: If the reference count is > 1, decrement 466 * it; otherwise free the block. 467 */ 468 static void 469 ext4_xattr_release_block(handle_t *handle, struct inode *inode, 470 struct buffer_head *bh) 471 { 472 struct mb_cache_entry *ce = NULL; 473 int error = 0; 474 475 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr); 476 error = ext4_journal_get_write_access(handle, bh); 477 if (error) 478 goto out; 479 480 lock_buffer(bh); 481 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) { 482 ea_bdebug(bh, "refcount now=0; freeing"); 483 if (ce) 484 mb_cache_entry_free(ce); 485 get_bh(bh); 486 ext4_free_blocks(handle, inode, bh, 0, 1, 487 EXT4_FREE_BLOCKS_METADATA | 488 EXT4_FREE_BLOCKS_FORGET); 489 } else { 490 le32_add_cpu(&BHDR(bh)->h_refcount, -1); 491 error = ext4_handle_dirty_metadata(handle, inode, bh); 492 if (IS_SYNC(inode)) 493 ext4_handle_sync(handle); 494 vfs_dq_free_block(inode, 1); 495 ea_bdebug(bh, "refcount now=%d; releasing", 496 le32_to_cpu(BHDR(bh)->h_refcount)); 497 if (ce) 498 mb_cache_entry_release(ce); 499 } 500 unlock_buffer(bh); 501 out: 502 ext4_std_error(inode->i_sb, error); 503 return; 504 } 505 506 /* 507 * Find the available free space for EAs. This also returns the total number of 508 * bytes used by EA entries. 509 */ 510 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last, 511 size_t *min_offs, void *base, int *total) 512 { 513 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 514 *total += EXT4_XATTR_LEN(last->e_name_len); 515 if (!last->e_value_block && last->e_value_size) { 516 size_t offs = le16_to_cpu(last->e_value_offs); 517 if (offs < *min_offs) 518 *min_offs = offs; 519 } 520 } 521 return (*min_offs - ((void *)last - base) - sizeof(__u32)); 522 } 523 524 struct ext4_xattr_info { 525 int name_index; 526 const char *name; 527 const void *value; 528 size_t value_len; 529 }; 530 531 struct ext4_xattr_search { 532 struct ext4_xattr_entry *first; 533 void *base; 534 void *end; 535 struct ext4_xattr_entry *here; 536 int not_found; 537 }; 538 539 static int 540 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s) 541 { 542 struct ext4_xattr_entry *last; 543 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name); 544 545 /* Compute min_offs and last. */ 546 last = s->first; 547 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 548 if (!last->e_value_block && last->e_value_size) { 549 size_t offs = le16_to_cpu(last->e_value_offs); 550 if (offs < min_offs) 551 min_offs = offs; 552 } 553 } 554 free = min_offs - ((void *)last - s->base) - sizeof(__u32); 555 if (!s->not_found) { 556 if (!s->here->e_value_block && s->here->e_value_size) { 557 size_t size = le32_to_cpu(s->here->e_value_size); 558 free += EXT4_XATTR_SIZE(size); 559 } 560 free += EXT4_XATTR_LEN(name_len); 561 } 562 if (i->value) { 563 if (free < EXT4_XATTR_SIZE(i->value_len) || 564 free < EXT4_XATTR_LEN(name_len) + 565 EXT4_XATTR_SIZE(i->value_len)) 566 return -ENOSPC; 567 } 568 569 if (i->value && s->not_found) { 570 /* Insert the new name. */ 571 size_t size = EXT4_XATTR_LEN(name_len); 572 size_t rest = (void *)last - (void *)s->here + sizeof(__u32); 573 memmove((void *)s->here + size, s->here, rest); 574 memset(s->here, 0, size); 575 s->here->e_name_index = i->name_index; 576 s->here->e_name_len = name_len; 577 memcpy(s->here->e_name, i->name, name_len); 578 } else { 579 if (!s->here->e_value_block && s->here->e_value_size) { 580 void *first_val = s->base + min_offs; 581 size_t offs = le16_to_cpu(s->here->e_value_offs); 582 void *val = s->base + offs; 583 size_t size = EXT4_XATTR_SIZE( 584 le32_to_cpu(s->here->e_value_size)); 585 586 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) { 587 /* The old and the new value have the same 588 size. Just replace. */ 589 s->here->e_value_size = 590 cpu_to_le32(i->value_len); 591 memset(val + size - EXT4_XATTR_PAD, 0, 592 EXT4_XATTR_PAD); /* Clear pad bytes. */ 593 memcpy(val, i->value, i->value_len); 594 return 0; 595 } 596 597 /* Remove the old value. */ 598 memmove(first_val + size, first_val, val - first_val); 599 memset(first_val, 0, size); 600 s->here->e_value_size = 0; 601 s->here->e_value_offs = 0; 602 min_offs += size; 603 604 /* Adjust all value offsets. */ 605 last = s->first; 606 while (!IS_LAST_ENTRY(last)) { 607 size_t o = le16_to_cpu(last->e_value_offs); 608 if (!last->e_value_block && 609 last->e_value_size && o < offs) 610 last->e_value_offs = 611 cpu_to_le16(o + size); 612 last = EXT4_XATTR_NEXT(last); 613 } 614 } 615 if (!i->value) { 616 /* Remove the old name. */ 617 size_t size = EXT4_XATTR_LEN(name_len); 618 last = ENTRY((void *)last - size); 619 memmove(s->here, (void *)s->here + size, 620 (void *)last - (void *)s->here + sizeof(__u32)); 621 memset(last, 0, size); 622 } 623 } 624 625 if (i->value) { 626 /* Insert the new value. */ 627 s->here->e_value_size = cpu_to_le32(i->value_len); 628 if (i->value_len) { 629 size_t size = EXT4_XATTR_SIZE(i->value_len); 630 void *val = s->base + min_offs - size; 631 s->here->e_value_offs = cpu_to_le16(min_offs - size); 632 memset(val + size - EXT4_XATTR_PAD, 0, 633 EXT4_XATTR_PAD); /* Clear the pad bytes. */ 634 memcpy(val, i->value, i->value_len); 635 } 636 } 637 return 0; 638 } 639 640 struct ext4_xattr_block_find { 641 struct ext4_xattr_search s; 642 struct buffer_head *bh; 643 }; 644 645 static int 646 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i, 647 struct ext4_xattr_block_find *bs) 648 { 649 struct super_block *sb = inode->i_sb; 650 int error; 651 652 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", 653 i->name_index, i->name, i->value, (long)i->value_len); 654 655 if (EXT4_I(inode)->i_file_acl) { 656 /* The inode already has an extended attribute block. */ 657 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl); 658 error = -EIO; 659 if (!bs->bh) 660 goto cleanup; 661 ea_bdebug(bs->bh, "b_count=%d, refcount=%d", 662 atomic_read(&(bs->bh->b_count)), 663 le32_to_cpu(BHDR(bs->bh)->h_refcount)); 664 if (ext4_xattr_check_block(bs->bh)) { 665 ext4_error(sb, __func__, 666 "inode %lu: bad block %llu", inode->i_ino, 667 EXT4_I(inode)->i_file_acl); 668 error = -EIO; 669 goto cleanup; 670 } 671 /* Find the named attribute. */ 672 bs->s.base = BHDR(bs->bh); 673 bs->s.first = BFIRST(bs->bh); 674 bs->s.end = bs->bh->b_data + bs->bh->b_size; 675 bs->s.here = bs->s.first; 676 error = ext4_xattr_find_entry(&bs->s.here, i->name_index, 677 i->name, bs->bh->b_size, 1); 678 if (error && error != -ENODATA) 679 goto cleanup; 680 bs->s.not_found = error; 681 } 682 error = 0; 683 684 cleanup: 685 return error; 686 } 687 688 static int 689 ext4_xattr_block_set(handle_t *handle, struct inode *inode, 690 struct ext4_xattr_info *i, 691 struct ext4_xattr_block_find *bs) 692 { 693 struct super_block *sb = inode->i_sb; 694 struct buffer_head *new_bh = NULL; 695 struct ext4_xattr_search *s = &bs->s; 696 struct mb_cache_entry *ce = NULL; 697 int error = 0; 698 699 #define header(x) ((struct ext4_xattr_header *)(x)) 700 701 if (i->value && i->value_len > sb->s_blocksize) 702 return -ENOSPC; 703 if (s->base) { 704 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev, 705 bs->bh->b_blocknr); 706 error = ext4_journal_get_write_access(handle, bs->bh); 707 if (error) 708 goto cleanup; 709 lock_buffer(bs->bh); 710 711 if (header(s->base)->h_refcount == cpu_to_le32(1)) { 712 if (ce) { 713 mb_cache_entry_free(ce); 714 ce = NULL; 715 } 716 ea_bdebug(bs->bh, "modifying in-place"); 717 error = ext4_xattr_set_entry(i, s); 718 if (!error) { 719 if (!IS_LAST_ENTRY(s->first)) 720 ext4_xattr_rehash(header(s->base), 721 s->here); 722 ext4_xattr_cache_insert(bs->bh); 723 } 724 unlock_buffer(bs->bh); 725 if (error == -EIO) 726 goto bad_block; 727 if (!error) 728 error = ext4_handle_dirty_metadata(handle, 729 inode, 730 bs->bh); 731 if (error) 732 goto cleanup; 733 goto inserted; 734 } else { 735 int offset = (char *)s->here - bs->bh->b_data; 736 737 unlock_buffer(bs->bh); 738 jbd2_journal_release_buffer(handle, bs->bh); 739 if (ce) { 740 mb_cache_entry_release(ce); 741 ce = NULL; 742 } 743 ea_bdebug(bs->bh, "cloning"); 744 s->base = kmalloc(bs->bh->b_size, GFP_NOFS); 745 error = -ENOMEM; 746 if (s->base == NULL) 747 goto cleanup; 748 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size); 749 s->first = ENTRY(header(s->base)+1); 750 header(s->base)->h_refcount = cpu_to_le32(1); 751 s->here = ENTRY(s->base + offset); 752 s->end = s->base + bs->bh->b_size; 753 } 754 } else { 755 /* Allocate a buffer where we construct the new block. */ 756 s->base = kzalloc(sb->s_blocksize, GFP_NOFS); 757 /* assert(header == s->base) */ 758 error = -ENOMEM; 759 if (s->base == NULL) 760 goto cleanup; 761 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 762 header(s->base)->h_blocks = cpu_to_le32(1); 763 header(s->base)->h_refcount = cpu_to_le32(1); 764 s->first = ENTRY(header(s->base)+1); 765 s->here = ENTRY(header(s->base)+1); 766 s->end = s->base + sb->s_blocksize; 767 } 768 769 error = ext4_xattr_set_entry(i, s); 770 if (error == -EIO) 771 goto bad_block; 772 if (error) 773 goto cleanup; 774 if (!IS_LAST_ENTRY(s->first)) 775 ext4_xattr_rehash(header(s->base), s->here); 776 777 inserted: 778 if (!IS_LAST_ENTRY(s->first)) { 779 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce); 780 if (new_bh) { 781 /* We found an identical block in the cache. */ 782 if (new_bh == bs->bh) 783 ea_bdebug(new_bh, "keeping"); 784 else { 785 /* The old block is released after updating 786 the inode. */ 787 error = -EDQUOT; 788 if (vfs_dq_alloc_block(inode, 1)) 789 goto cleanup; 790 error = ext4_journal_get_write_access(handle, 791 new_bh); 792 if (error) 793 goto cleanup_dquot; 794 lock_buffer(new_bh); 795 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1); 796 ea_bdebug(new_bh, "reusing; refcount now=%d", 797 le32_to_cpu(BHDR(new_bh)->h_refcount)); 798 unlock_buffer(new_bh); 799 error = ext4_handle_dirty_metadata(handle, 800 inode, 801 new_bh); 802 if (error) 803 goto cleanup_dquot; 804 } 805 mb_cache_entry_release(ce); 806 ce = NULL; 807 } else if (bs->bh && s->base == bs->bh->b_data) { 808 /* We were modifying this block in-place. */ 809 ea_bdebug(bs->bh, "keeping this block"); 810 new_bh = bs->bh; 811 get_bh(new_bh); 812 } else { 813 /* We need to allocate a new block */ 814 ext4_fsblk_t goal, block; 815 816 goal = ext4_group_first_block_no(sb, 817 EXT4_I(inode)->i_block_group); 818 819 /* non-extent files can't have physical blocks past 2^32 */ 820 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 821 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS; 822 823 block = ext4_new_meta_blocks(handle, inode, 824 goal, NULL, &error); 825 if (error) 826 goto cleanup; 827 828 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 829 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS); 830 831 ea_idebug(inode, "creating block %d", block); 832 833 new_bh = sb_getblk(sb, block); 834 if (!new_bh) { 835 getblk_failed: 836 ext4_free_blocks(handle, inode, 0, block, 1, 837 EXT4_FREE_BLOCKS_METADATA); 838 error = -EIO; 839 goto cleanup; 840 } 841 lock_buffer(new_bh); 842 error = ext4_journal_get_create_access(handle, new_bh); 843 if (error) { 844 unlock_buffer(new_bh); 845 goto getblk_failed; 846 } 847 memcpy(new_bh->b_data, s->base, new_bh->b_size); 848 set_buffer_uptodate(new_bh); 849 unlock_buffer(new_bh); 850 ext4_xattr_cache_insert(new_bh); 851 error = ext4_handle_dirty_metadata(handle, 852 inode, new_bh); 853 if (error) 854 goto cleanup; 855 } 856 } 857 858 /* Update the inode. */ 859 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; 860 861 /* Drop the previous xattr block. */ 862 if (bs->bh && bs->bh != new_bh) 863 ext4_xattr_release_block(handle, inode, bs->bh); 864 error = 0; 865 866 cleanup: 867 if (ce) 868 mb_cache_entry_release(ce); 869 brelse(new_bh); 870 if (!(bs->bh && s->base == bs->bh->b_data)) 871 kfree(s->base); 872 873 return error; 874 875 cleanup_dquot: 876 vfs_dq_free_block(inode, 1); 877 goto cleanup; 878 879 bad_block: 880 ext4_error(inode->i_sb, __func__, 881 "inode %lu: bad block %llu", inode->i_ino, 882 EXT4_I(inode)->i_file_acl); 883 goto cleanup; 884 885 #undef header 886 } 887 888 struct ext4_xattr_ibody_find { 889 struct ext4_xattr_search s; 890 struct ext4_iloc iloc; 891 }; 892 893 static int 894 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, 895 struct ext4_xattr_ibody_find *is) 896 { 897 struct ext4_xattr_ibody_header *header; 898 struct ext4_inode *raw_inode; 899 int error; 900 901 if (EXT4_I(inode)->i_extra_isize == 0) 902 return 0; 903 raw_inode = ext4_raw_inode(&is->iloc); 904 header = IHDR(inode, raw_inode); 905 is->s.base = is->s.first = IFIRST(header); 906 is->s.here = is->s.first; 907 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 908 if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) { 909 error = ext4_xattr_check_names(IFIRST(header), is->s.end); 910 if (error) 911 return error; 912 /* Find the named attribute. */ 913 error = ext4_xattr_find_entry(&is->s.here, i->name_index, 914 i->name, is->s.end - 915 (void *)is->s.base, 0); 916 if (error && error != -ENODATA) 917 return error; 918 is->s.not_found = error; 919 } 920 return 0; 921 } 922 923 static int 924 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode, 925 struct ext4_xattr_info *i, 926 struct ext4_xattr_ibody_find *is) 927 { 928 struct ext4_xattr_ibody_header *header; 929 struct ext4_xattr_search *s = &is->s; 930 int error; 931 932 if (EXT4_I(inode)->i_extra_isize == 0) 933 return -ENOSPC; 934 error = ext4_xattr_set_entry(i, s); 935 if (error) 936 return error; 937 header = IHDR(inode, ext4_raw_inode(&is->iloc)); 938 if (!IS_LAST_ENTRY(s->first)) { 939 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 940 EXT4_I(inode)->i_state |= EXT4_STATE_XATTR; 941 } else { 942 header->h_magic = cpu_to_le32(0); 943 EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR; 944 } 945 return 0; 946 } 947 948 /* 949 * ext4_xattr_set_handle() 950 * 951 * Create, replace or remove an extended attribute for this inode. Buffer 952 * is NULL to remove an existing extended attribute, and non-NULL to 953 * either replace an existing extended attribute, or create a new extended 954 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 955 * specify that an extended attribute must exist and must not exist 956 * previous to the call, respectively. 957 * 958 * Returns 0, or a negative error number on failure. 959 */ 960 int 961 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, 962 const char *name, const void *value, size_t value_len, 963 int flags) 964 { 965 struct ext4_xattr_info i = { 966 .name_index = name_index, 967 .name = name, 968 .value = value, 969 .value_len = value_len, 970 971 }; 972 struct ext4_xattr_ibody_find is = { 973 .s = { .not_found = -ENODATA, }, 974 }; 975 struct ext4_xattr_block_find bs = { 976 .s = { .not_found = -ENODATA, }, 977 }; 978 unsigned long no_expand; 979 int error; 980 981 if (!name) 982 return -EINVAL; 983 if (strlen(name) > 255) 984 return -ERANGE; 985 down_write(&EXT4_I(inode)->xattr_sem); 986 no_expand = EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND; 987 EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND; 988 989 error = ext4_get_inode_loc(inode, &is.iloc); 990 if (error) 991 goto cleanup; 992 993 error = ext4_journal_get_write_access(handle, is.iloc.bh); 994 if (error) 995 goto cleanup; 996 997 if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) { 998 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc); 999 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); 1000 EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW; 1001 } 1002 1003 error = ext4_xattr_ibody_find(inode, &i, &is); 1004 if (error) 1005 goto cleanup; 1006 if (is.s.not_found) 1007 error = ext4_xattr_block_find(inode, &i, &bs); 1008 if (error) 1009 goto cleanup; 1010 if (is.s.not_found && bs.s.not_found) { 1011 error = -ENODATA; 1012 if (flags & XATTR_REPLACE) 1013 goto cleanup; 1014 error = 0; 1015 if (!value) 1016 goto cleanup; 1017 } else { 1018 error = -EEXIST; 1019 if (flags & XATTR_CREATE) 1020 goto cleanup; 1021 } 1022 if (!value) { 1023 if (!is.s.not_found) 1024 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1025 else if (!bs.s.not_found) 1026 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1027 } else { 1028 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1029 if (!error && !bs.s.not_found) { 1030 i.value = NULL; 1031 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1032 } else if (error == -ENOSPC) { 1033 if (EXT4_I(inode)->i_file_acl && !bs.s.base) { 1034 error = ext4_xattr_block_find(inode, &i, &bs); 1035 if (error) 1036 goto cleanup; 1037 } 1038 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1039 if (error) 1040 goto cleanup; 1041 if (!is.s.not_found) { 1042 i.value = NULL; 1043 error = ext4_xattr_ibody_set(handle, inode, &i, 1044 &is); 1045 } 1046 } 1047 } 1048 if (!error) { 1049 ext4_xattr_update_super_block(handle, inode->i_sb); 1050 inode->i_ctime = ext4_current_time(inode); 1051 if (!value) 1052 EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND; 1053 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc); 1054 /* 1055 * The bh is consumed by ext4_mark_iloc_dirty, even with 1056 * error != 0. 1057 */ 1058 is.iloc.bh = NULL; 1059 if (IS_SYNC(inode)) 1060 ext4_handle_sync(handle); 1061 } 1062 1063 cleanup: 1064 brelse(is.iloc.bh); 1065 brelse(bs.bh); 1066 if (no_expand == 0) 1067 EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND; 1068 up_write(&EXT4_I(inode)->xattr_sem); 1069 return error; 1070 } 1071 1072 /* 1073 * ext4_xattr_set() 1074 * 1075 * Like ext4_xattr_set_handle, but start from an inode. This extended 1076 * attribute modification is a filesystem transaction by itself. 1077 * 1078 * Returns 0, or a negative error number on failure. 1079 */ 1080 int 1081 ext4_xattr_set(struct inode *inode, int name_index, const char *name, 1082 const void *value, size_t value_len, int flags) 1083 { 1084 handle_t *handle; 1085 int error, retries = 0; 1086 1087 retry: 1088 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb)); 1089 if (IS_ERR(handle)) { 1090 error = PTR_ERR(handle); 1091 } else { 1092 int error2; 1093 1094 error = ext4_xattr_set_handle(handle, inode, name_index, name, 1095 value, value_len, flags); 1096 error2 = ext4_journal_stop(handle); 1097 if (error == -ENOSPC && 1098 ext4_should_retry_alloc(inode->i_sb, &retries)) 1099 goto retry; 1100 if (error == 0) 1101 error = error2; 1102 } 1103 1104 return error; 1105 } 1106 1107 /* 1108 * Shift the EA entries in the inode to create space for the increased 1109 * i_extra_isize. 1110 */ 1111 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry, 1112 int value_offs_shift, void *to, 1113 void *from, size_t n, int blocksize) 1114 { 1115 struct ext4_xattr_entry *last = entry; 1116 int new_offs; 1117 1118 /* Adjust the value offsets of the entries */ 1119 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1120 if (!last->e_value_block && last->e_value_size) { 1121 new_offs = le16_to_cpu(last->e_value_offs) + 1122 value_offs_shift; 1123 BUG_ON(new_offs + le32_to_cpu(last->e_value_size) 1124 > blocksize); 1125 last->e_value_offs = cpu_to_le16(new_offs); 1126 } 1127 } 1128 /* Shift the entries by n bytes */ 1129 memmove(to, from, n); 1130 } 1131 1132 /* 1133 * Expand an inode by new_extra_isize bytes when EAs are present. 1134 * Returns 0 on success or negative error number on failure. 1135 */ 1136 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, 1137 struct ext4_inode *raw_inode, handle_t *handle) 1138 { 1139 struct ext4_xattr_ibody_header *header; 1140 struct ext4_xattr_entry *entry, *last, *first; 1141 struct buffer_head *bh = NULL; 1142 struct ext4_xattr_ibody_find *is = NULL; 1143 struct ext4_xattr_block_find *bs = NULL; 1144 char *buffer = NULL, *b_entry_name = NULL; 1145 size_t min_offs, free; 1146 int total_ino, total_blk; 1147 void *base, *start, *end; 1148 int extra_isize = 0, error = 0, tried_min_extra_isize = 0; 1149 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize); 1150 1151 down_write(&EXT4_I(inode)->xattr_sem); 1152 retry: 1153 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) { 1154 up_write(&EXT4_I(inode)->xattr_sem); 1155 return 0; 1156 } 1157 1158 header = IHDR(inode, raw_inode); 1159 entry = IFIRST(header); 1160 1161 /* 1162 * Check if enough free space is available in the inode to shift the 1163 * entries ahead by new_extra_isize. 1164 */ 1165 1166 base = start = entry; 1167 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 1168 min_offs = end - base; 1169 last = entry; 1170 total_ino = sizeof(struct ext4_xattr_ibody_header); 1171 1172 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino); 1173 if (free >= new_extra_isize) { 1174 entry = IFIRST(header); 1175 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize 1176 - new_extra_isize, (void *)raw_inode + 1177 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize, 1178 (void *)header, total_ino, 1179 inode->i_sb->s_blocksize); 1180 EXT4_I(inode)->i_extra_isize = new_extra_isize; 1181 error = 0; 1182 goto cleanup; 1183 } 1184 1185 /* 1186 * Enough free space isn't available in the inode, check if 1187 * EA block can hold new_extra_isize bytes. 1188 */ 1189 if (EXT4_I(inode)->i_file_acl) { 1190 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1191 error = -EIO; 1192 if (!bh) 1193 goto cleanup; 1194 if (ext4_xattr_check_block(bh)) { 1195 ext4_error(inode->i_sb, __func__, 1196 "inode %lu: bad block %llu", inode->i_ino, 1197 EXT4_I(inode)->i_file_acl); 1198 error = -EIO; 1199 goto cleanup; 1200 } 1201 base = BHDR(bh); 1202 first = BFIRST(bh); 1203 end = bh->b_data + bh->b_size; 1204 min_offs = end - base; 1205 free = ext4_xattr_free_space(first, &min_offs, base, 1206 &total_blk); 1207 if (free < new_extra_isize) { 1208 if (!tried_min_extra_isize && s_min_extra_isize) { 1209 tried_min_extra_isize++; 1210 new_extra_isize = s_min_extra_isize; 1211 brelse(bh); 1212 goto retry; 1213 } 1214 error = -1; 1215 goto cleanup; 1216 } 1217 } else { 1218 free = inode->i_sb->s_blocksize; 1219 } 1220 1221 while (new_extra_isize > 0) { 1222 size_t offs, size, entry_size; 1223 struct ext4_xattr_entry *small_entry = NULL; 1224 struct ext4_xattr_info i = { 1225 .value = NULL, 1226 .value_len = 0, 1227 }; 1228 unsigned int total_size; /* EA entry size + value size */ 1229 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */ 1230 unsigned int min_total_size = ~0U; 1231 1232 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS); 1233 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS); 1234 if (!is || !bs) { 1235 error = -ENOMEM; 1236 goto cleanup; 1237 } 1238 1239 is->s.not_found = -ENODATA; 1240 bs->s.not_found = -ENODATA; 1241 is->iloc.bh = NULL; 1242 bs->bh = NULL; 1243 1244 last = IFIRST(header); 1245 /* Find the entry best suited to be pushed into EA block */ 1246 entry = NULL; 1247 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1248 total_size = 1249 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) + 1250 EXT4_XATTR_LEN(last->e_name_len); 1251 if (total_size <= free && total_size < min_total_size) { 1252 if (total_size < new_extra_isize) { 1253 small_entry = last; 1254 } else { 1255 entry = last; 1256 min_total_size = total_size; 1257 } 1258 } 1259 } 1260 1261 if (entry == NULL) { 1262 if (small_entry) { 1263 entry = small_entry; 1264 } else { 1265 if (!tried_min_extra_isize && 1266 s_min_extra_isize) { 1267 tried_min_extra_isize++; 1268 new_extra_isize = s_min_extra_isize; 1269 goto retry; 1270 } 1271 error = -1; 1272 goto cleanup; 1273 } 1274 } 1275 offs = le16_to_cpu(entry->e_value_offs); 1276 size = le32_to_cpu(entry->e_value_size); 1277 entry_size = EXT4_XATTR_LEN(entry->e_name_len); 1278 i.name_index = entry->e_name_index, 1279 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS); 1280 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS); 1281 if (!buffer || !b_entry_name) { 1282 error = -ENOMEM; 1283 goto cleanup; 1284 } 1285 /* Save the entry name and the entry value */ 1286 memcpy(buffer, (void *)IFIRST(header) + offs, 1287 EXT4_XATTR_SIZE(size)); 1288 memcpy(b_entry_name, entry->e_name, entry->e_name_len); 1289 b_entry_name[entry->e_name_len] = '\0'; 1290 i.name = b_entry_name; 1291 1292 error = ext4_get_inode_loc(inode, &is->iloc); 1293 if (error) 1294 goto cleanup; 1295 1296 error = ext4_xattr_ibody_find(inode, &i, is); 1297 if (error) 1298 goto cleanup; 1299 1300 /* Remove the chosen entry from the inode */ 1301 error = ext4_xattr_ibody_set(handle, inode, &i, is); 1302 1303 entry = IFIRST(header); 1304 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize) 1305 shift_bytes = new_extra_isize; 1306 else 1307 shift_bytes = entry_size + size; 1308 /* Adjust the offsets and shift the remaining entries ahead */ 1309 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize - 1310 shift_bytes, (void *)raw_inode + 1311 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes, 1312 (void *)header, total_ino - entry_size, 1313 inode->i_sb->s_blocksize); 1314 1315 extra_isize += shift_bytes; 1316 new_extra_isize -= shift_bytes; 1317 EXT4_I(inode)->i_extra_isize = extra_isize; 1318 1319 i.name = b_entry_name; 1320 i.value = buffer; 1321 i.value_len = size; 1322 error = ext4_xattr_block_find(inode, &i, bs); 1323 if (error) 1324 goto cleanup; 1325 1326 /* Add entry which was removed from the inode into the block */ 1327 error = ext4_xattr_block_set(handle, inode, &i, bs); 1328 if (error) 1329 goto cleanup; 1330 kfree(b_entry_name); 1331 kfree(buffer); 1332 brelse(is->iloc.bh); 1333 kfree(is); 1334 kfree(bs); 1335 } 1336 brelse(bh); 1337 up_write(&EXT4_I(inode)->xattr_sem); 1338 return 0; 1339 1340 cleanup: 1341 kfree(b_entry_name); 1342 kfree(buffer); 1343 if (is) 1344 brelse(is->iloc.bh); 1345 kfree(is); 1346 kfree(bs); 1347 brelse(bh); 1348 up_write(&EXT4_I(inode)->xattr_sem); 1349 return error; 1350 } 1351 1352 1353 1354 /* 1355 * ext4_xattr_delete_inode() 1356 * 1357 * Free extended attribute resources associated with this inode. This 1358 * is called immediately before an inode is freed. We have exclusive 1359 * access to the inode. 1360 */ 1361 void 1362 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode) 1363 { 1364 struct buffer_head *bh = NULL; 1365 1366 if (!EXT4_I(inode)->i_file_acl) 1367 goto cleanup; 1368 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1369 if (!bh) { 1370 ext4_error(inode->i_sb, __func__, 1371 "inode %lu: block %llu read error", inode->i_ino, 1372 EXT4_I(inode)->i_file_acl); 1373 goto cleanup; 1374 } 1375 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 1376 BHDR(bh)->h_blocks != cpu_to_le32(1)) { 1377 ext4_error(inode->i_sb, __func__, 1378 "inode %lu: bad block %llu", inode->i_ino, 1379 EXT4_I(inode)->i_file_acl); 1380 goto cleanup; 1381 } 1382 ext4_xattr_release_block(handle, inode, bh); 1383 EXT4_I(inode)->i_file_acl = 0; 1384 1385 cleanup: 1386 brelse(bh); 1387 } 1388 1389 /* 1390 * ext4_xattr_put_super() 1391 * 1392 * This is called when a file system is unmounted. 1393 */ 1394 void 1395 ext4_xattr_put_super(struct super_block *sb) 1396 { 1397 mb_cache_shrink(sb->s_bdev); 1398 } 1399 1400 /* 1401 * ext4_xattr_cache_insert() 1402 * 1403 * Create a new entry in the extended attribute cache, and insert 1404 * it unless such an entry is already in the cache. 1405 * 1406 * Returns 0, or a negative error number on failure. 1407 */ 1408 static void 1409 ext4_xattr_cache_insert(struct buffer_head *bh) 1410 { 1411 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash); 1412 struct mb_cache_entry *ce; 1413 int error; 1414 1415 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS); 1416 if (!ce) { 1417 ea_bdebug(bh, "out of memory"); 1418 return; 1419 } 1420 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash); 1421 if (error) { 1422 mb_cache_entry_free(ce); 1423 if (error == -EBUSY) { 1424 ea_bdebug(bh, "already in cache"); 1425 error = 0; 1426 } 1427 } else { 1428 ea_bdebug(bh, "inserting [%x]", (int)hash); 1429 mb_cache_entry_release(ce); 1430 } 1431 } 1432 1433 /* 1434 * ext4_xattr_cmp() 1435 * 1436 * Compare two extended attribute blocks for equality. 1437 * 1438 * Returns 0 if the blocks are equal, 1 if they differ, and 1439 * a negative error number on errors. 1440 */ 1441 static int 1442 ext4_xattr_cmp(struct ext4_xattr_header *header1, 1443 struct ext4_xattr_header *header2) 1444 { 1445 struct ext4_xattr_entry *entry1, *entry2; 1446 1447 entry1 = ENTRY(header1+1); 1448 entry2 = ENTRY(header2+1); 1449 while (!IS_LAST_ENTRY(entry1)) { 1450 if (IS_LAST_ENTRY(entry2)) 1451 return 1; 1452 if (entry1->e_hash != entry2->e_hash || 1453 entry1->e_name_index != entry2->e_name_index || 1454 entry1->e_name_len != entry2->e_name_len || 1455 entry1->e_value_size != entry2->e_value_size || 1456 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) 1457 return 1; 1458 if (entry1->e_value_block != 0 || entry2->e_value_block != 0) 1459 return -EIO; 1460 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), 1461 (char *)header2 + le16_to_cpu(entry2->e_value_offs), 1462 le32_to_cpu(entry1->e_value_size))) 1463 return 1; 1464 1465 entry1 = EXT4_XATTR_NEXT(entry1); 1466 entry2 = EXT4_XATTR_NEXT(entry2); 1467 } 1468 if (!IS_LAST_ENTRY(entry2)) 1469 return 1; 1470 return 0; 1471 } 1472 1473 /* 1474 * ext4_xattr_cache_find() 1475 * 1476 * Find an identical extended attribute block. 1477 * 1478 * Returns a pointer to the block found, or NULL if such a block was 1479 * not found or an error occurred. 1480 */ 1481 static struct buffer_head * 1482 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header, 1483 struct mb_cache_entry **pce) 1484 { 1485 __u32 hash = le32_to_cpu(header->h_hash); 1486 struct mb_cache_entry *ce; 1487 1488 if (!header->h_hash) 1489 return NULL; /* never share */ 1490 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); 1491 again: 1492 ce = mb_cache_entry_find_first(ext4_xattr_cache, 0, 1493 inode->i_sb->s_bdev, hash); 1494 while (ce) { 1495 struct buffer_head *bh; 1496 1497 if (IS_ERR(ce)) { 1498 if (PTR_ERR(ce) == -EAGAIN) 1499 goto again; 1500 break; 1501 } 1502 bh = sb_bread(inode->i_sb, ce->e_block); 1503 if (!bh) { 1504 ext4_error(inode->i_sb, __func__, 1505 "inode %lu: block %lu read error", 1506 inode->i_ino, (unsigned long) ce->e_block); 1507 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >= 1508 EXT4_XATTR_REFCOUNT_MAX) { 1509 ea_idebug(inode, "block %lu refcount %d>=%d", 1510 (unsigned long) ce->e_block, 1511 le32_to_cpu(BHDR(bh)->h_refcount), 1512 EXT4_XATTR_REFCOUNT_MAX); 1513 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) { 1514 *pce = ce; 1515 return bh; 1516 } 1517 brelse(bh); 1518 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash); 1519 } 1520 return NULL; 1521 } 1522 1523 #define NAME_HASH_SHIFT 5 1524 #define VALUE_HASH_SHIFT 16 1525 1526 /* 1527 * ext4_xattr_hash_entry() 1528 * 1529 * Compute the hash of an extended attribute. 1530 */ 1531 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header, 1532 struct ext4_xattr_entry *entry) 1533 { 1534 __u32 hash = 0; 1535 char *name = entry->e_name; 1536 int n; 1537 1538 for (n = 0; n < entry->e_name_len; n++) { 1539 hash = (hash << NAME_HASH_SHIFT) ^ 1540 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ 1541 *name++; 1542 } 1543 1544 if (entry->e_value_block == 0 && entry->e_value_size != 0) { 1545 __le32 *value = (__le32 *)((char *)header + 1546 le16_to_cpu(entry->e_value_offs)); 1547 for (n = (le32_to_cpu(entry->e_value_size) + 1548 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) { 1549 hash = (hash << VALUE_HASH_SHIFT) ^ 1550 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ 1551 le32_to_cpu(*value++); 1552 } 1553 } 1554 entry->e_hash = cpu_to_le32(hash); 1555 } 1556 1557 #undef NAME_HASH_SHIFT 1558 #undef VALUE_HASH_SHIFT 1559 1560 #define BLOCK_HASH_SHIFT 16 1561 1562 /* 1563 * ext4_xattr_rehash() 1564 * 1565 * Re-compute the extended attribute hash value after an entry has changed. 1566 */ 1567 static void ext4_xattr_rehash(struct ext4_xattr_header *header, 1568 struct ext4_xattr_entry *entry) 1569 { 1570 struct ext4_xattr_entry *here; 1571 __u32 hash = 0; 1572 1573 ext4_xattr_hash_entry(header, entry); 1574 here = ENTRY(header+1); 1575 while (!IS_LAST_ENTRY(here)) { 1576 if (!here->e_hash) { 1577 /* Block is not shared if an entry's hash value == 0 */ 1578 hash = 0; 1579 break; 1580 } 1581 hash = (hash << BLOCK_HASH_SHIFT) ^ 1582 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ 1583 le32_to_cpu(here->e_hash); 1584 here = EXT4_XATTR_NEXT(here); 1585 } 1586 header->h_hash = cpu_to_le32(hash); 1587 } 1588 1589 #undef BLOCK_HASH_SHIFT 1590 1591 int __init 1592 init_ext4_xattr(void) 1593 { 1594 ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL, 1595 sizeof(struct mb_cache_entry) + 1596 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6); 1597 if (!ext4_xattr_cache) 1598 return -ENOMEM; 1599 return 0; 1600 } 1601 1602 void 1603 exit_ext4_xattr(void) 1604 { 1605 if (ext4_xattr_cache) 1606 mb_cache_destroy(ext4_xattr_cache); 1607 ext4_xattr_cache = NULL; 1608 } 1609