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_EXT4DEV_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_EXT4DEV_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_EXT4DEV_FS_POSIX_ACL 116 &ext4_xattr_acl_access_handler, 117 &ext4_xattr_acl_default_handler, 118 #endif 119 #ifdef CONFIG_EXT4DEV_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_journal_dirty_metadata(handle, 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 ext4_free_blocks(handle, inode, bh->b_blocknr, 1, 1); 486 get_bh(bh); 487 ext4_forget(handle, 1, inode, bh, bh->b_blocknr); 488 } else { 489 le32_add_cpu(&BHDR(bh)->h_refcount, -1); 490 error = ext4_journal_dirty_metadata(handle, bh); 491 if (IS_SYNC(inode)) 492 handle->h_sync = 1; 493 DQUOT_FREE_BLOCK(inode, 1); 494 ea_bdebug(bh, "refcount now=%d; releasing", 495 le32_to_cpu(BHDR(bh)->h_refcount)); 496 if (ce) 497 mb_cache_entry_release(ce); 498 } 499 unlock_buffer(bh); 500 out: 501 ext4_std_error(inode->i_sb, error); 502 return; 503 } 504 505 /* 506 * Find the available free space for EAs. This also returns the total number of 507 * bytes used by EA entries. 508 */ 509 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last, 510 size_t *min_offs, void *base, int *total) 511 { 512 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 513 *total += EXT4_XATTR_LEN(last->e_name_len); 514 if (!last->e_value_block && last->e_value_size) { 515 size_t offs = le16_to_cpu(last->e_value_offs); 516 if (offs < *min_offs) 517 *min_offs = offs; 518 } 519 } 520 return (*min_offs - ((void *)last - base) - sizeof(__u32)); 521 } 522 523 struct ext4_xattr_info { 524 int name_index; 525 const char *name; 526 const void *value; 527 size_t value_len; 528 }; 529 530 struct ext4_xattr_search { 531 struct ext4_xattr_entry *first; 532 void *base; 533 void *end; 534 struct ext4_xattr_entry *here; 535 int not_found; 536 }; 537 538 static int 539 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s) 540 { 541 struct ext4_xattr_entry *last; 542 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name); 543 544 /* Compute min_offs and last. */ 545 last = s->first; 546 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 547 if (!last->e_value_block && last->e_value_size) { 548 size_t offs = le16_to_cpu(last->e_value_offs); 549 if (offs < min_offs) 550 min_offs = offs; 551 } 552 } 553 free = min_offs - ((void *)last - s->base) - sizeof(__u32); 554 if (!s->not_found) { 555 if (!s->here->e_value_block && s->here->e_value_size) { 556 size_t size = le32_to_cpu(s->here->e_value_size); 557 free += EXT4_XATTR_SIZE(size); 558 } 559 free += EXT4_XATTR_LEN(name_len); 560 } 561 if (i->value) { 562 if (free < EXT4_XATTR_SIZE(i->value_len) || 563 free < EXT4_XATTR_LEN(name_len) + 564 EXT4_XATTR_SIZE(i->value_len)) 565 return -ENOSPC; 566 } 567 568 if (i->value && s->not_found) { 569 /* Insert the new name. */ 570 size_t size = EXT4_XATTR_LEN(name_len); 571 size_t rest = (void *)last - (void *)s->here + sizeof(__u32); 572 memmove((void *)s->here + size, s->here, rest); 573 memset(s->here, 0, size); 574 s->here->e_name_index = i->name_index; 575 s->here->e_name_len = name_len; 576 memcpy(s->here->e_name, i->name, name_len); 577 } else { 578 if (!s->here->e_value_block && s->here->e_value_size) { 579 void *first_val = s->base + min_offs; 580 size_t offs = le16_to_cpu(s->here->e_value_offs); 581 void *val = s->base + offs; 582 size_t size = EXT4_XATTR_SIZE( 583 le32_to_cpu(s->here->e_value_size)); 584 585 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) { 586 /* The old and the new value have the same 587 size. Just replace. */ 588 s->here->e_value_size = 589 cpu_to_le32(i->value_len); 590 memset(val + size - EXT4_XATTR_PAD, 0, 591 EXT4_XATTR_PAD); /* Clear pad bytes. */ 592 memcpy(val, i->value, i->value_len); 593 return 0; 594 } 595 596 /* Remove the old value. */ 597 memmove(first_val + size, first_val, val - first_val); 598 memset(first_val, 0, size); 599 s->here->e_value_size = 0; 600 s->here->e_value_offs = 0; 601 min_offs += size; 602 603 /* Adjust all value offsets. */ 604 last = s->first; 605 while (!IS_LAST_ENTRY(last)) { 606 size_t o = le16_to_cpu(last->e_value_offs); 607 if (!last->e_value_block && 608 last->e_value_size && o < offs) 609 last->e_value_offs = 610 cpu_to_le16(o + size); 611 last = EXT4_XATTR_NEXT(last); 612 } 613 } 614 if (!i->value) { 615 /* Remove the old name. */ 616 size_t size = EXT4_XATTR_LEN(name_len); 617 last = ENTRY((void *)last - size); 618 memmove(s->here, (void *)s->here + size, 619 (void *)last - (void *)s->here + sizeof(__u32)); 620 memset(last, 0, size); 621 } 622 } 623 624 if (i->value) { 625 /* Insert the new value. */ 626 s->here->e_value_size = cpu_to_le32(i->value_len); 627 if (i->value_len) { 628 size_t size = EXT4_XATTR_SIZE(i->value_len); 629 void *val = s->base + min_offs - size; 630 s->here->e_value_offs = cpu_to_le16(min_offs - size); 631 memset(val + size - EXT4_XATTR_PAD, 0, 632 EXT4_XATTR_PAD); /* Clear the pad bytes. */ 633 memcpy(val, i->value, i->value_len); 634 } 635 } 636 return 0; 637 } 638 639 struct ext4_xattr_block_find { 640 struct ext4_xattr_search s; 641 struct buffer_head *bh; 642 }; 643 644 static int 645 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i, 646 struct ext4_xattr_block_find *bs) 647 { 648 struct super_block *sb = inode->i_sb; 649 int error; 650 651 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", 652 i->name_index, i->name, i->value, (long)i->value_len); 653 654 if (EXT4_I(inode)->i_file_acl) { 655 /* The inode already has an extended attribute block. */ 656 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl); 657 error = -EIO; 658 if (!bs->bh) 659 goto cleanup; 660 ea_bdebug(bs->bh, "b_count=%d, refcount=%d", 661 atomic_read(&(bs->bh->b_count)), 662 le32_to_cpu(BHDR(bs->bh)->h_refcount)); 663 if (ext4_xattr_check_block(bs->bh)) { 664 ext4_error(sb, __func__, 665 "inode %lu: bad block %llu", inode->i_ino, 666 EXT4_I(inode)->i_file_acl); 667 error = -EIO; 668 goto cleanup; 669 } 670 /* Find the named attribute. */ 671 bs->s.base = BHDR(bs->bh); 672 bs->s.first = BFIRST(bs->bh); 673 bs->s.end = bs->bh->b_data + bs->bh->b_size; 674 bs->s.here = bs->s.first; 675 error = ext4_xattr_find_entry(&bs->s.here, i->name_index, 676 i->name, bs->bh->b_size, 1); 677 if (error && error != -ENODATA) 678 goto cleanup; 679 bs->s.not_found = error; 680 } 681 error = 0; 682 683 cleanup: 684 return error; 685 } 686 687 static int 688 ext4_xattr_block_set(handle_t *handle, struct inode *inode, 689 struct ext4_xattr_info *i, 690 struct ext4_xattr_block_find *bs) 691 { 692 struct super_block *sb = inode->i_sb; 693 struct buffer_head *new_bh = NULL; 694 struct ext4_xattr_search *s = &bs->s; 695 struct mb_cache_entry *ce = NULL; 696 int error = 0; 697 698 #define header(x) ((struct ext4_xattr_header *)(x)) 699 700 if (i->value && i->value_len > sb->s_blocksize) 701 return -ENOSPC; 702 if (s->base) { 703 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev, 704 bs->bh->b_blocknr); 705 error = ext4_journal_get_write_access(handle, bs->bh); 706 if (error) 707 goto cleanup; 708 lock_buffer(bs->bh); 709 710 if (header(s->base)->h_refcount == cpu_to_le32(1)) { 711 if (ce) { 712 mb_cache_entry_free(ce); 713 ce = NULL; 714 } 715 ea_bdebug(bs->bh, "modifying in-place"); 716 error = ext4_xattr_set_entry(i, s); 717 if (!error) { 718 if (!IS_LAST_ENTRY(s->first)) 719 ext4_xattr_rehash(header(s->base), 720 s->here); 721 ext4_xattr_cache_insert(bs->bh); 722 } 723 unlock_buffer(bs->bh); 724 if (error == -EIO) 725 goto bad_block; 726 if (!error) 727 error = ext4_journal_dirty_metadata(handle, 728 bs->bh); 729 if (error) 730 goto cleanup; 731 goto inserted; 732 } else { 733 int offset = (char *)s->here - bs->bh->b_data; 734 735 unlock_buffer(bs->bh); 736 jbd2_journal_release_buffer(handle, bs->bh); 737 if (ce) { 738 mb_cache_entry_release(ce); 739 ce = NULL; 740 } 741 ea_bdebug(bs->bh, "cloning"); 742 s->base = kmalloc(bs->bh->b_size, GFP_NOFS); 743 error = -ENOMEM; 744 if (s->base == NULL) 745 goto cleanup; 746 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size); 747 s->first = ENTRY(header(s->base)+1); 748 header(s->base)->h_refcount = cpu_to_le32(1); 749 s->here = ENTRY(s->base + offset); 750 s->end = s->base + bs->bh->b_size; 751 } 752 } else { 753 /* Allocate a buffer where we construct the new block. */ 754 s->base = kzalloc(sb->s_blocksize, GFP_NOFS); 755 /* assert(header == s->base) */ 756 error = -ENOMEM; 757 if (s->base == NULL) 758 goto cleanup; 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 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1); 794 ea_bdebug(new_bh, "reusing; refcount now=%d", 795 le32_to_cpu(BHDR(new_bh)->h_refcount)); 796 unlock_buffer(new_bh); 797 error = ext4_journal_dirty_metadata(handle, 798 new_bh); 799 if (error) 800 goto cleanup_dquot; 801 } 802 mb_cache_entry_release(ce); 803 ce = NULL; 804 } else if (bs->bh && s->base == bs->bh->b_data) { 805 /* We were modifying this block in-place. */ 806 ea_bdebug(bs->bh, "keeping this block"); 807 new_bh = bs->bh; 808 get_bh(new_bh); 809 } else { 810 /* We need to allocate a new block */ 811 ext4_fsblk_t goal = ext4_group_first_block_no(sb, 812 EXT4_I(inode)->i_block_group); 813 ext4_fsblk_t block = ext4_new_meta_block(handle, inode, 814 goal, &error); 815 if (error) 816 goto cleanup; 817 ea_idebug(inode, "creating block %d", block); 818 819 new_bh = sb_getblk(sb, block); 820 if (!new_bh) { 821 getblk_failed: 822 ext4_free_blocks(handle, inode, block, 1, 1); 823 error = -EIO; 824 goto cleanup; 825 } 826 lock_buffer(new_bh); 827 error = ext4_journal_get_create_access(handle, new_bh); 828 if (error) { 829 unlock_buffer(new_bh); 830 goto getblk_failed; 831 } 832 memcpy(new_bh->b_data, s->base, new_bh->b_size); 833 set_buffer_uptodate(new_bh); 834 unlock_buffer(new_bh); 835 ext4_xattr_cache_insert(new_bh); 836 error = ext4_journal_dirty_metadata(handle, new_bh); 837 if (error) 838 goto cleanup; 839 } 840 } 841 842 /* Update the inode. */ 843 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; 844 845 /* Drop the previous xattr block. */ 846 if (bs->bh && bs->bh != new_bh) 847 ext4_xattr_release_block(handle, inode, bs->bh); 848 error = 0; 849 850 cleanup: 851 if (ce) 852 mb_cache_entry_release(ce); 853 brelse(new_bh); 854 if (!(bs->bh && s->base == bs->bh->b_data)) 855 kfree(s->base); 856 857 return error; 858 859 cleanup_dquot: 860 DQUOT_FREE_BLOCK(inode, 1); 861 goto cleanup; 862 863 bad_block: 864 ext4_error(inode->i_sb, __func__, 865 "inode %lu: bad block %llu", inode->i_ino, 866 EXT4_I(inode)->i_file_acl); 867 goto cleanup; 868 869 #undef header 870 } 871 872 struct ext4_xattr_ibody_find { 873 struct ext4_xattr_search s; 874 struct ext4_iloc iloc; 875 }; 876 877 static int 878 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, 879 struct ext4_xattr_ibody_find *is) 880 { 881 struct ext4_xattr_ibody_header *header; 882 struct ext4_inode *raw_inode; 883 int error; 884 885 if (EXT4_I(inode)->i_extra_isize == 0) 886 return 0; 887 raw_inode = ext4_raw_inode(&is->iloc); 888 header = IHDR(inode, raw_inode); 889 is->s.base = is->s.first = IFIRST(header); 890 is->s.here = is->s.first; 891 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 892 if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) { 893 error = ext4_xattr_check_names(IFIRST(header), is->s.end); 894 if (error) 895 return error; 896 /* Find the named attribute. */ 897 error = ext4_xattr_find_entry(&is->s.here, i->name_index, 898 i->name, is->s.end - 899 (void *)is->s.base, 0); 900 if (error && error != -ENODATA) 901 return error; 902 is->s.not_found = error; 903 } 904 return 0; 905 } 906 907 static int 908 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode, 909 struct ext4_xattr_info *i, 910 struct ext4_xattr_ibody_find *is) 911 { 912 struct ext4_xattr_ibody_header *header; 913 struct ext4_xattr_search *s = &is->s; 914 int error; 915 916 if (EXT4_I(inode)->i_extra_isize == 0) 917 return -ENOSPC; 918 error = ext4_xattr_set_entry(i, s); 919 if (error) 920 return error; 921 header = IHDR(inode, ext4_raw_inode(&is->iloc)); 922 if (!IS_LAST_ENTRY(s->first)) { 923 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 924 EXT4_I(inode)->i_state |= EXT4_STATE_XATTR; 925 } else { 926 header->h_magic = cpu_to_le32(0); 927 EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR; 928 } 929 return 0; 930 } 931 932 /* 933 * ext4_xattr_set_handle() 934 * 935 * Create, replace or remove an extended attribute for this inode. Buffer 936 * is NULL to remove an existing extended attribute, and non-NULL to 937 * either replace an existing extended attribute, or create a new extended 938 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 939 * specify that an extended attribute must exist and must not exist 940 * previous to the call, respectively. 941 * 942 * Returns 0, or a negative error number on failure. 943 */ 944 int 945 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, 946 const char *name, const void *value, size_t value_len, 947 int flags) 948 { 949 struct ext4_xattr_info i = { 950 .name_index = name_index, 951 .name = name, 952 .value = value, 953 .value_len = value_len, 954 955 }; 956 struct ext4_xattr_ibody_find is = { 957 .s = { .not_found = -ENODATA, }, 958 }; 959 struct ext4_xattr_block_find bs = { 960 .s = { .not_found = -ENODATA, }, 961 }; 962 int error; 963 964 if (!name) 965 return -EINVAL; 966 if (strlen(name) > 255) 967 return -ERANGE; 968 down_write(&EXT4_I(inode)->xattr_sem); 969 error = ext4_get_inode_loc(inode, &is.iloc); 970 if (error) 971 goto cleanup; 972 973 if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) { 974 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc); 975 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); 976 EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW; 977 } 978 979 error = ext4_xattr_ibody_find(inode, &i, &is); 980 if (error) 981 goto cleanup; 982 if (is.s.not_found) 983 error = ext4_xattr_block_find(inode, &i, &bs); 984 if (error) 985 goto cleanup; 986 if (is.s.not_found && bs.s.not_found) { 987 error = -ENODATA; 988 if (flags & XATTR_REPLACE) 989 goto cleanup; 990 error = 0; 991 if (!value) 992 goto cleanup; 993 } else { 994 error = -EEXIST; 995 if (flags & XATTR_CREATE) 996 goto cleanup; 997 } 998 error = ext4_journal_get_write_access(handle, is.iloc.bh); 999 if (error) 1000 goto cleanup; 1001 if (!value) { 1002 if (!is.s.not_found) 1003 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1004 else if (!bs.s.not_found) 1005 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1006 } else { 1007 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1008 if (!error && !bs.s.not_found) { 1009 i.value = NULL; 1010 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1011 } else if (error == -ENOSPC) { 1012 if (EXT4_I(inode)->i_file_acl && !bs.s.base) { 1013 error = ext4_xattr_block_find(inode, &i, &bs); 1014 if (error) 1015 goto cleanup; 1016 } 1017 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1018 if (error) 1019 goto cleanup; 1020 if (!is.s.not_found) { 1021 i.value = NULL; 1022 error = ext4_xattr_ibody_set(handle, inode, &i, 1023 &is); 1024 } 1025 } 1026 } 1027 if (!error) { 1028 ext4_xattr_update_super_block(handle, inode->i_sb); 1029 inode->i_ctime = ext4_current_time(inode); 1030 if (!value) 1031 EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND; 1032 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc); 1033 /* 1034 * The bh is consumed by ext4_mark_iloc_dirty, even with 1035 * error != 0. 1036 */ 1037 is.iloc.bh = NULL; 1038 if (IS_SYNC(inode)) 1039 handle->h_sync = 1; 1040 } 1041 1042 cleanup: 1043 brelse(is.iloc.bh); 1044 brelse(bs.bh); 1045 up_write(&EXT4_I(inode)->xattr_sem); 1046 return error; 1047 } 1048 1049 /* 1050 * ext4_xattr_set() 1051 * 1052 * Like ext4_xattr_set_handle, but start from an inode. This extended 1053 * attribute modification is a filesystem transaction by itself. 1054 * 1055 * Returns 0, or a negative error number on failure. 1056 */ 1057 int 1058 ext4_xattr_set(struct inode *inode, int name_index, const char *name, 1059 const void *value, size_t value_len, int flags) 1060 { 1061 handle_t *handle; 1062 int error, retries = 0; 1063 1064 retry: 1065 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb)); 1066 if (IS_ERR(handle)) { 1067 error = PTR_ERR(handle); 1068 } else { 1069 int error2; 1070 1071 error = ext4_xattr_set_handle(handle, inode, name_index, name, 1072 value, value_len, flags); 1073 error2 = ext4_journal_stop(handle); 1074 if (error == -ENOSPC && 1075 ext4_should_retry_alloc(inode->i_sb, &retries)) 1076 goto retry; 1077 if (error == 0) 1078 error = error2; 1079 } 1080 1081 return error; 1082 } 1083 1084 /* 1085 * Shift the EA entries in the inode to create space for the increased 1086 * i_extra_isize. 1087 */ 1088 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry, 1089 int value_offs_shift, void *to, 1090 void *from, size_t n, int blocksize) 1091 { 1092 struct ext4_xattr_entry *last = entry; 1093 int new_offs; 1094 1095 /* Adjust the value offsets of the entries */ 1096 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1097 if (!last->e_value_block && last->e_value_size) { 1098 new_offs = le16_to_cpu(last->e_value_offs) + 1099 value_offs_shift; 1100 BUG_ON(new_offs + le32_to_cpu(last->e_value_size) 1101 > blocksize); 1102 last->e_value_offs = cpu_to_le16(new_offs); 1103 } 1104 } 1105 /* Shift the entries by n bytes */ 1106 memmove(to, from, n); 1107 } 1108 1109 /* 1110 * Expand an inode by new_extra_isize bytes when EAs are present. 1111 * Returns 0 on success or negative error number on failure. 1112 */ 1113 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, 1114 struct ext4_inode *raw_inode, handle_t *handle) 1115 { 1116 struct ext4_xattr_ibody_header *header; 1117 struct ext4_xattr_entry *entry, *last, *first; 1118 struct buffer_head *bh = NULL; 1119 struct ext4_xattr_ibody_find *is = NULL; 1120 struct ext4_xattr_block_find *bs = NULL; 1121 char *buffer = NULL, *b_entry_name = NULL; 1122 size_t min_offs, free; 1123 int total_ino, total_blk; 1124 void *base, *start, *end; 1125 int extra_isize = 0, error = 0, tried_min_extra_isize = 0; 1126 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize); 1127 1128 down_write(&EXT4_I(inode)->xattr_sem); 1129 retry: 1130 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) { 1131 up_write(&EXT4_I(inode)->xattr_sem); 1132 return 0; 1133 } 1134 1135 header = IHDR(inode, raw_inode); 1136 entry = IFIRST(header); 1137 1138 /* 1139 * Check if enough free space is available in the inode to shift the 1140 * entries ahead by new_extra_isize. 1141 */ 1142 1143 base = start = entry; 1144 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 1145 min_offs = end - base; 1146 last = entry; 1147 total_ino = sizeof(struct ext4_xattr_ibody_header); 1148 1149 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino); 1150 if (free >= new_extra_isize) { 1151 entry = IFIRST(header); 1152 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize 1153 - new_extra_isize, (void *)raw_inode + 1154 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize, 1155 (void *)header, total_ino, 1156 inode->i_sb->s_blocksize); 1157 EXT4_I(inode)->i_extra_isize = new_extra_isize; 1158 error = 0; 1159 goto cleanup; 1160 } 1161 1162 /* 1163 * Enough free space isn't available in the inode, check if 1164 * EA block can hold new_extra_isize bytes. 1165 */ 1166 if (EXT4_I(inode)->i_file_acl) { 1167 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1168 error = -EIO; 1169 if (!bh) 1170 goto cleanup; 1171 if (ext4_xattr_check_block(bh)) { 1172 ext4_error(inode->i_sb, __func__, 1173 "inode %lu: bad block %llu", inode->i_ino, 1174 EXT4_I(inode)->i_file_acl); 1175 error = -EIO; 1176 goto cleanup; 1177 } 1178 base = BHDR(bh); 1179 first = BFIRST(bh); 1180 end = bh->b_data + bh->b_size; 1181 min_offs = end - base; 1182 free = ext4_xattr_free_space(first, &min_offs, base, 1183 &total_blk); 1184 if (free < new_extra_isize) { 1185 if (!tried_min_extra_isize && s_min_extra_isize) { 1186 tried_min_extra_isize++; 1187 new_extra_isize = s_min_extra_isize; 1188 brelse(bh); 1189 goto retry; 1190 } 1191 error = -1; 1192 goto cleanup; 1193 } 1194 } else { 1195 free = inode->i_sb->s_blocksize; 1196 } 1197 1198 while (new_extra_isize > 0) { 1199 size_t offs, size, entry_size; 1200 struct ext4_xattr_entry *small_entry = NULL; 1201 struct ext4_xattr_info i = { 1202 .value = NULL, 1203 .value_len = 0, 1204 }; 1205 unsigned int total_size; /* EA entry size + value size */ 1206 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */ 1207 unsigned int min_total_size = ~0U; 1208 1209 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS); 1210 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS); 1211 if (!is || !bs) { 1212 error = -ENOMEM; 1213 goto cleanup; 1214 } 1215 1216 is->s.not_found = -ENODATA; 1217 bs->s.not_found = -ENODATA; 1218 is->iloc.bh = NULL; 1219 bs->bh = NULL; 1220 1221 last = IFIRST(header); 1222 /* Find the entry best suited to be pushed into EA block */ 1223 entry = NULL; 1224 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1225 total_size = 1226 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) + 1227 EXT4_XATTR_LEN(last->e_name_len); 1228 if (total_size <= free && total_size < min_total_size) { 1229 if (total_size < new_extra_isize) { 1230 small_entry = last; 1231 } else { 1232 entry = last; 1233 min_total_size = total_size; 1234 } 1235 } 1236 } 1237 1238 if (entry == NULL) { 1239 if (small_entry) { 1240 entry = small_entry; 1241 } else { 1242 if (!tried_min_extra_isize && 1243 s_min_extra_isize) { 1244 tried_min_extra_isize++; 1245 new_extra_isize = s_min_extra_isize; 1246 goto retry; 1247 } 1248 error = -1; 1249 goto cleanup; 1250 } 1251 } 1252 offs = le16_to_cpu(entry->e_value_offs); 1253 size = le32_to_cpu(entry->e_value_size); 1254 entry_size = EXT4_XATTR_LEN(entry->e_name_len); 1255 i.name_index = entry->e_name_index, 1256 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS); 1257 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS); 1258 if (!buffer || !b_entry_name) { 1259 error = -ENOMEM; 1260 goto cleanup; 1261 } 1262 /* Save the entry name and the entry value */ 1263 memcpy(buffer, (void *)IFIRST(header) + offs, 1264 EXT4_XATTR_SIZE(size)); 1265 memcpy(b_entry_name, entry->e_name, entry->e_name_len); 1266 b_entry_name[entry->e_name_len] = '\0'; 1267 i.name = b_entry_name; 1268 1269 error = ext4_get_inode_loc(inode, &is->iloc); 1270 if (error) 1271 goto cleanup; 1272 1273 error = ext4_xattr_ibody_find(inode, &i, is); 1274 if (error) 1275 goto cleanup; 1276 1277 /* Remove the chosen entry from the inode */ 1278 error = ext4_xattr_ibody_set(handle, inode, &i, is); 1279 1280 entry = IFIRST(header); 1281 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize) 1282 shift_bytes = new_extra_isize; 1283 else 1284 shift_bytes = entry_size + size; 1285 /* Adjust the offsets and shift the remaining entries ahead */ 1286 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize - 1287 shift_bytes, (void *)raw_inode + 1288 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes, 1289 (void *)header, total_ino - entry_size, 1290 inode->i_sb->s_blocksize); 1291 1292 extra_isize += shift_bytes; 1293 new_extra_isize -= shift_bytes; 1294 EXT4_I(inode)->i_extra_isize = extra_isize; 1295 1296 i.name = b_entry_name; 1297 i.value = buffer; 1298 i.value_len = size; 1299 error = ext4_xattr_block_find(inode, &i, bs); 1300 if (error) 1301 goto cleanup; 1302 1303 /* Add entry which was removed from the inode into the block */ 1304 error = ext4_xattr_block_set(handle, inode, &i, bs); 1305 if (error) 1306 goto cleanup; 1307 kfree(b_entry_name); 1308 kfree(buffer); 1309 brelse(is->iloc.bh); 1310 kfree(is); 1311 kfree(bs); 1312 } 1313 brelse(bh); 1314 up_write(&EXT4_I(inode)->xattr_sem); 1315 return 0; 1316 1317 cleanup: 1318 kfree(b_entry_name); 1319 kfree(buffer); 1320 if (is) 1321 brelse(is->iloc.bh); 1322 kfree(is); 1323 kfree(bs); 1324 brelse(bh); 1325 up_write(&EXT4_I(inode)->xattr_sem); 1326 return error; 1327 } 1328 1329 1330 1331 /* 1332 * ext4_xattr_delete_inode() 1333 * 1334 * Free extended attribute resources associated with this inode. This 1335 * is called immediately before an inode is freed. We have exclusive 1336 * access to the inode. 1337 */ 1338 void 1339 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode) 1340 { 1341 struct buffer_head *bh = NULL; 1342 1343 if (!EXT4_I(inode)->i_file_acl) 1344 goto cleanup; 1345 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1346 if (!bh) { 1347 ext4_error(inode->i_sb, __func__, 1348 "inode %lu: block %llu read error", inode->i_ino, 1349 EXT4_I(inode)->i_file_acl); 1350 goto cleanup; 1351 } 1352 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 1353 BHDR(bh)->h_blocks != cpu_to_le32(1)) { 1354 ext4_error(inode->i_sb, __func__, 1355 "inode %lu: bad block %llu", inode->i_ino, 1356 EXT4_I(inode)->i_file_acl); 1357 goto cleanup; 1358 } 1359 ext4_xattr_release_block(handle, inode, bh); 1360 EXT4_I(inode)->i_file_acl = 0; 1361 1362 cleanup: 1363 brelse(bh); 1364 } 1365 1366 /* 1367 * ext4_xattr_put_super() 1368 * 1369 * This is called when a file system is unmounted. 1370 */ 1371 void 1372 ext4_xattr_put_super(struct super_block *sb) 1373 { 1374 mb_cache_shrink(sb->s_bdev); 1375 } 1376 1377 /* 1378 * ext4_xattr_cache_insert() 1379 * 1380 * Create a new entry in the extended attribute cache, and insert 1381 * it unless such an entry is already in the cache. 1382 * 1383 * Returns 0, or a negative error number on failure. 1384 */ 1385 static void 1386 ext4_xattr_cache_insert(struct buffer_head *bh) 1387 { 1388 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash); 1389 struct mb_cache_entry *ce; 1390 int error; 1391 1392 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS); 1393 if (!ce) { 1394 ea_bdebug(bh, "out of memory"); 1395 return; 1396 } 1397 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash); 1398 if (error) { 1399 mb_cache_entry_free(ce); 1400 if (error == -EBUSY) { 1401 ea_bdebug(bh, "already in cache"); 1402 error = 0; 1403 } 1404 } else { 1405 ea_bdebug(bh, "inserting [%x]", (int)hash); 1406 mb_cache_entry_release(ce); 1407 } 1408 } 1409 1410 /* 1411 * ext4_xattr_cmp() 1412 * 1413 * Compare two extended attribute blocks for equality. 1414 * 1415 * Returns 0 if the blocks are equal, 1 if they differ, and 1416 * a negative error number on errors. 1417 */ 1418 static int 1419 ext4_xattr_cmp(struct ext4_xattr_header *header1, 1420 struct ext4_xattr_header *header2) 1421 { 1422 struct ext4_xattr_entry *entry1, *entry2; 1423 1424 entry1 = ENTRY(header1+1); 1425 entry2 = ENTRY(header2+1); 1426 while (!IS_LAST_ENTRY(entry1)) { 1427 if (IS_LAST_ENTRY(entry2)) 1428 return 1; 1429 if (entry1->e_hash != entry2->e_hash || 1430 entry1->e_name_index != entry2->e_name_index || 1431 entry1->e_name_len != entry2->e_name_len || 1432 entry1->e_value_size != entry2->e_value_size || 1433 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) 1434 return 1; 1435 if (entry1->e_value_block != 0 || entry2->e_value_block != 0) 1436 return -EIO; 1437 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), 1438 (char *)header2 + le16_to_cpu(entry2->e_value_offs), 1439 le32_to_cpu(entry1->e_value_size))) 1440 return 1; 1441 1442 entry1 = EXT4_XATTR_NEXT(entry1); 1443 entry2 = EXT4_XATTR_NEXT(entry2); 1444 } 1445 if (!IS_LAST_ENTRY(entry2)) 1446 return 1; 1447 return 0; 1448 } 1449 1450 /* 1451 * ext4_xattr_cache_find() 1452 * 1453 * Find an identical extended attribute block. 1454 * 1455 * Returns a pointer to the block found, or NULL if such a block was 1456 * not found or an error occurred. 1457 */ 1458 static struct buffer_head * 1459 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header, 1460 struct mb_cache_entry **pce) 1461 { 1462 __u32 hash = le32_to_cpu(header->h_hash); 1463 struct mb_cache_entry *ce; 1464 1465 if (!header->h_hash) 1466 return NULL; /* never share */ 1467 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); 1468 again: 1469 ce = mb_cache_entry_find_first(ext4_xattr_cache, 0, 1470 inode->i_sb->s_bdev, hash); 1471 while (ce) { 1472 struct buffer_head *bh; 1473 1474 if (IS_ERR(ce)) { 1475 if (PTR_ERR(ce) == -EAGAIN) 1476 goto again; 1477 break; 1478 } 1479 bh = sb_bread(inode->i_sb, ce->e_block); 1480 if (!bh) { 1481 ext4_error(inode->i_sb, __func__, 1482 "inode %lu: block %lu read error", 1483 inode->i_ino, (unsigned long) ce->e_block); 1484 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >= 1485 EXT4_XATTR_REFCOUNT_MAX) { 1486 ea_idebug(inode, "block %lu refcount %d>=%d", 1487 (unsigned long) ce->e_block, 1488 le32_to_cpu(BHDR(bh)->h_refcount), 1489 EXT4_XATTR_REFCOUNT_MAX); 1490 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) { 1491 *pce = ce; 1492 return bh; 1493 } 1494 brelse(bh); 1495 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash); 1496 } 1497 return NULL; 1498 } 1499 1500 #define NAME_HASH_SHIFT 5 1501 #define VALUE_HASH_SHIFT 16 1502 1503 /* 1504 * ext4_xattr_hash_entry() 1505 * 1506 * Compute the hash of an extended attribute. 1507 */ 1508 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header, 1509 struct ext4_xattr_entry *entry) 1510 { 1511 __u32 hash = 0; 1512 char *name = entry->e_name; 1513 int n; 1514 1515 for (n=0; n < entry->e_name_len; n++) { 1516 hash = (hash << NAME_HASH_SHIFT) ^ 1517 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ 1518 *name++; 1519 } 1520 1521 if (entry->e_value_block == 0 && entry->e_value_size != 0) { 1522 __le32 *value = (__le32 *)((char *)header + 1523 le16_to_cpu(entry->e_value_offs)); 1524 for (n = (le32_to_cpu(entry->e_value_size) + 1525 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) { 1526 hash = (hash << VALUE_HASH_SHIFT) ^ 1527 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ 1528 le32_to_cpu(*value++); 1529 } 1530 } 1531 entry->e_hash = cpu_to_le32(hash); 1532 } 1533 1534 #undef NAME_HASH_SHIFT 1535 #undef VALUE_HASH_SHIFT 1536 1537 #define BLOCK_HASH_SHIFT 16 1538 1539 /* 1540 * ext4_xattr_rehash() 1541 * 1542 * Re-compute the extended attribute hash value after an entry has changed. 1543 */ 1544 static void ext4_xattr_rehash(struct ext4_xattr_header *header, 1545 struct ext4_xattr_entry *entry) 1546 { 1547 struct ext4_xattr_entry *here; 1548 __u32 hash = 0; 1549 1550 ext4_xattr_hash_entry(header, entry); 1551 here = ENTRY(header+1); 1552 while (!IS_LAST_ENTRY(here)) { 1553 if (!here->e_hash) { 1554 /* Block is not shared if an entry's hash value == 0 */ 1555 hash = 0; 1556 break; 1557 } 1558 hash = (hash << BLOCK_HASH_SHIFT) ^ 1559 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ 1560 le32_to_cpu(here->e_hash); 1561 here = EXT4_XATTR_NEXT(here); 1562 } 1563 header->h_hash = cpu_to_le32(hash); 1564 } 1565 1566 #undef BLOCK_HASH_SHIFT 1567 1568 int __init 1569 init_ext4_xattr(void) 1570 { 1571 ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL, 1572 sizeof(struct mb_cache_entry) + 1573 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6); 1574 if (!ext4_xattr_cache) 1575 return -ENOMEM; 1576 return 0; 1577 } 1578 1579 void 1580 exit_ext4_xattr(void) 1581 { 1582 if (ext4_xattr_cache) 1583 mb_cache_destroy(ext4_xattr_cache); 1584 ext4_xattr_cache = NULL; 1585 } 1586