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 dentry *dentry, 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, 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: 231 ext4_error(inode->i_sb, 232 "inode %lu: bad block %llu", inode->i_ino, 233 EXT4_I(inode)->i_file_acl); 234 error = -EIO; 235 goto cleanup; 236 } 237 ext4_xattr_cache_insert(bh); 238 entry = BFIRST(bh); 239 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1); 240 if (error == -EIO) 241 goto bad_block; 242 if (error) 243 goto cleanup; 244 size = le32_to_cpu(entry->e_value_size); 245 if (buffer) { 246 error = -ERANGE; 247 if (size > buffer_size) 248 goto cleanup; 249 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), 250 size); 251 } 252 error = size; 253 254 cleanup: 255 brelse(bh); 256 return error; 257 } 258 259 static int 260 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name, 261 void *buffer, size_t buffer_size) 262 { 263 struct ext4_xattr_ibody_header *header; 264 struct ext4_xattr_entry *entry; 265 struct ext4_inode *raw_inode; 266 struct ext4_iloc iloc; 267 size_t size; 268 void *end; 269 int error; 270 271 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR)) 272 return -ENODATA; 273 error = ext4_get_inode_loc(inode, &iloc); 274 if (error) 275 return error; 276 raw_inode = ext4_raw_inode(&iloc); 277 header = IHDR(inode, raw_inode); 278 entry = IFIRST(header); 279 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 280 error = ext4_xattr_check_names(entry, end); 281 if (error) 282 goto cleanup; 283 error = ext4_xattr_find_entry(&entry, name_index, name, 284 end - (void *)entry, 0); 285 if (error) 286 goto cleanup; 287 size = le32_to_cpu(entry->e_value_size); 288 if (buffer) { 289 error = -ERANGE; 290 if (size > buffer_size) 291 goto cleanup; 292 memcpy(buffer, (void *)IFIRST(header) + 293 le16_to_cpu(entry->e_value_offs), size); 294 } 295 error = size; 296 297 cleanup: 298 brelse(iloc.bh); 299 return error; 300 } 301 302 /* 303 * ext4_xattr_get() 304 * 305 * Copy an extended attribute into the buffer 306 * provided, or compute the buffer size required. 307 * Buffer is NULL to compute the size of the buffer required. 308 * 309 * Returns a negative error number on failure, or the number of bytes 310 * used / required on success. 311 */ 312 int 313 ext4_xattr_get(struct inode *inode, int name_index, const char *name, 314 void *buffer, size_t buffer_size) 315 { 316 int error; 317 318 down_read(&EXT4_I(inode)->xattr_sem); 319 error = ext4_xattr_ibody_get(inode, name_index, name, buffer, 320 buffer_size); 321 if (error == -ENODATA) 322 error = ext4_xattr_block_get(inode, name_index, name, buffer, 323 buffer_size); 324 up_read(&EXT4_I(inode)->xattr_sem); 325 return error; 326 } 327 328 static int 329 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry, 330 char *buffer, size_t buffer_size) 331 { 332 size_t rest = buffer_size; 333 334 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 335 struct xattr_handler *handler = 336 ext4_xattr_handler(entry->e_name_index); 337 338 if (handler) { 339 size_t size = handler->list(dentry, buffer, rest, 340 entry->e_name, 341 entry->e_name_len, 342 handler->flags); 343 if (buffer) { 344 if (size > rest) 345 return -ERANGE; 346 buffer += size; 347 } 348 rest -= size; 349 } 350 } 351 return buffer_size - rest; 352 } 353 354 static int 355 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size) 356 { 357 struct inode *inode = dentry->d_inode; 358 struct buffer_head *bh = NULL; 359 int error; 360 361 ea_idebug(inode, "buffer=%p, buffer_size=%ld", 362 buffer, (long)buffer_size); 363 364 error = 0; 365 if (!EXT4_I(inode)->i_file_acl) 366 goto cleanup; 367 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl); 368 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 369 error = -EIO; 370 if (!bh) 371 goto cleanup; 372 ea_bdebug(bh, "b_count=%d, refcount=%d", 373 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 374 if (ext4_xattr_check_block(bh)) { 375 ext4_error(inode->i_sb, 376 "inode %lu: bad block %llu", inode->i_ino, 377 EXT4_I(inode)->i_file_acl); 378 error = -EIO; 379 goto cleanup; 380 } 381 ext4_xattr_cache_insert(bh); 382 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size); 383 384 cleanup: 385 brelse(bh); 386 387 return error; 388 } 389 390 static int 391 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size) 392 { 393 struct inode *inode = dentry->d_inode; 394 struct ext4_xattr_ibody_header *header; 395 struct ext4_inode *raw_inode; 396 struct ext4_iloc iloc; 397 void *end; 398 int error; 399 400 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR)) 401 return 0; 402 error = ext4_get_inode_loc(inode, &iloc); 403 if (error) 404 return error; 405 raw_inode = ext4_raw_inode(&iloc); 406 header = IHDR(inode, raw_inode); 407 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 408 error = ext4_xattr_check_names(IFIRST(header), end); 409 if (error) 410 goto cleanup; 411 error = ext4_xattr_list_entries(dentry, IFIRST(header), 412 buffer, buffer_size); 413 414 cleanup: 415 brelse(iloc.bh); 416 return error; 417 } 418 419 /* 420 * ext4_xattr_list() 421 * 422 * Copy a list of attribute names into the buffer 423 * provided, or compute the buffer size required. 424 * Buffer is NULL to compute the size of the buffer required. 425 * 426 * Returns a negative error number on failure, or the number of bytes 427 * used / required on success. 428 */ 429 static int 430 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size) 431 { 432 int i_error, b_error; 433 434 down_read(&EXT4_I(dentry->d_inode)->xattr_sem); 435 i_error = ext4_xattr_ibody_list(dentry, buffer, buffer_size); 436 if (i_error < 0) { 437 b_error = 0; 438 } else { 439 if (buffer) { 440 buffer += i_error; 441 buffer_size -= i_error; 442 } 443 b_error = ext4_xattr_block_list(dentry, buffer, buffer_size); 444 if (b_error < 0) 445 i_error = 0; 446 } 447 up_read(&EXT4_I(dentry->d_inode)->xattr_sem); 448 return i_error + b_error; 449 } 450 451 /* 452 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is 453 * not set, set it. 454 */ 455 static void ext4_xattr_update_super_block(handle_t *handle, 456 struct super_block *sb) 457 { 458 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR)) 459 return; 460 461 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) { 462 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR); 463 sb->s_dirt = 1; 464 ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh); 465 } 466 } 467 468 /* 469 * Release the xattr block BH: If the reference count is > 1, decrement 470 * it; otherwise free the block. 471 */ 472 static void 473 ext4_xattr_release_block(handle_t *handle, struct inode *inode, 474 struct buffer_head *bh) 475 { 476 struct mb_cache_entry *ce = NULL; 477 int error = 0; 478 479 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr); 480 error = ext4_journal_get_write_access(handle, bh); 481 if (error) 482 goto out; 483 484 lock_buffer(bh); 485 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) { 486 ea_bdebug(bh, "refcount now=0; freeing"); 487 if (ce) 488 mb_cache_entry_free(ce); 489 get_bh(bh); 490 ext4_free_blocks(handle, inode, bh, 0, 1, 491 EXT4_FREE_BLOCKS_METADATA | 492 EXT4_FREE_BLOCKS_FORGET); 493 } else { 494 le32_add_cpu(&BHDR(bh)->h_refcount, -1); 495 error = ext4_handle_dirty_metadata(handle, inode, bh); 496 if (IS_SYNC(inode)) 497 ext4_handle_sync(handle); 498 dquot_free_block(inode, 1); 499 ea_bdebug(bh, "refcount now=%d; releasing", 500 le32_to_cpu(BHDR(bh)->h_refcount)); 501 if (ce) 502 mb_cache_entry_release(ce); 503 } 504 unlock_buffer(bh); 505 out: 506 ext4_std_error(inode->i_sb, error); 507 return; 508 } 509 510 /* 511 * Find the available free space for EAs. This also returns the total number of 512 * bytes used by EA entries. 513 */ 514 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last, 515 size_t *min_offs, void *base, int *total) 516 { 517 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 518 *total += EXT4_XATTR_LEN(last->e_name_len); 519 if (!last->e_value_block && last->e_value_size) { 520 size_t offs = le16_to_cpu(last->e_value_offs); 521 if (offs < *min_offs) 522 *min_offs = offs; 523 } 524 } 525 return (*min_offs - ((void *)last - base) - sizeof(__u32)); 526 } 527 528 struct ext4_xattr_info { 529 int name_index; 530 const char *name; 531 const void *value; 532 size_t value_len; 533 }; 534 535 struct ext4_xattr_search { 536 struct ext4_xattr_entry *first; 537 void *base; 538 void *end; 539 struct ext4_xattr_entry *here; 540 int not_found; 541 }; 542 543 static int 544 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s) 545 { 546 struct ext4_xattr_entry *last; 547 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name); 548 549 /* Compute min_offs and last. */ 550 last = s->first; 551 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 552 if (!last->e_value_block && last->e_value_size) { 553 size_t offs = le16_to_cpu(last->e_value_offs); 554 if (offs < min_offs) 555 min_offs = offs; 556 } 557 } 558 free = min_offs - ((void *)last - s->base) - sizeof(__u32); 559 if (!s->not_found) { 560 if (!s->here->e_value_block && s->here->e_value_size) { 561 size_t size = le32_to_cpu(s->here->e_value_size); 562 free += EXT4_XATTR_SIZE(size); 563 } 564 free += EXT4_XATTR_LEN(name_len); 565 } 566 if (i->value) { 567 if (free < EXT4_XATTR_SIZE(i->value_len) || 568 free < EXT4_XATTR_LEN(name_len) + 569 EXT4_XATTR_SIZE(i->value_len)) 570 return -ENOSPC; 571 } 572 573 if (i->value && s->not_found) { 574 /* Insert the new name. */ 575 size_t size = EXT4_XATTR_LEN(name_len); 576 size_t rest = (void *)last - (void *)s->here + sizeof(__u32); 577 memmove((void *)s->here + size, s->here, rest); 578 memset(s->here, 0, size); 579 s->here->e_name_index = i->name_index; 580 s->here->e_name_len = name_len; 581 memcpy(s->here->e_name, i->name, name_len); 582 } else { 583 if (!s->here->e_value_block && s->here->e_value_size) { 584 void *first_val = s->base + min_offs; 585 size_t offs = le16_to_cpu(s->here->e_value_offs); 586 void *val = s->base + offs; 587 size_t size = EXT4_XATTR_SIZE( 588 le32_to_cpu(s->here->e_value_size)); 589 590 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) { 591 /* The old and the new value have the same 592 size. Just replace. */ 593 s->here->e_value_size = 594 cpu_to_le32(i->value_len); 595 memset(val + size - EXT4_XATTR_PAD, 0, 596 EXT4_XATTR_PAD); /* Clear pad bytes. */ 597 memcpy(val, i->value, i->value_len); 598 return 0; 599 } 600 601 /* Remove the old value. */ 602 memmove(first_val + size, first_val, val - first_val); 603 memset(first_val, 0, size); 604 s->here->e_value_size = 0; 605 s->here->e_value_offs = 0; 606 min_offs += size; 607 608 /* Adjust all value offsets. */ 609 last = s->first; 610 while (!IS_LAST_ENTRY(last)) { 611 size_t o = le16_to_cpu(last->e_value_offs); 612 if (!last->e_value_block && 613 last->e_value_size && o < offs) 614 last->e_value_offs = 615 cpu_to_le16(o + size); 616 last = EXT4_XATTR_NEXT(last); 617 } 618 } 619 if (!i->value) { 620 /* Remove the old name. */ 621 size_t size = EXT4_XATTR_LEN(name_len); 622 last = ENTRY((void *)last - size); 623 memmove(s->here, (void *)s->here + size, 624 (void *)last - (void *)s->here + sizeof(__u32)); 625 memset(last, 0, size); 626 } 627 } 628 629 if (i->value) { 630 /* Insert the new value. */ 631 s->here->e_value_size = cpu_to_le32(i->value_len); 632 if (i->value_len) { 633 size_t size = EXT4_XATTR_SIZE(i->value_len); 634 void *val = s->base + min_offs - size; 635 s->here->e_value_offs = cpu_to_le16(min_offs - size); 636 memset(val + size - EXT4_XATTR_PAD, 0, 637 EXT4_XATTR_PAD); /* Clear the pad bytes. */ 638 memcpy(val, i->value, i->value_len); 639 } 640 } 641 return 0; 642 } 643 644 struct ext4_xattr_block_find { 645 struct ext4_xattr_search s; 646 struct buffer_head *bh; 647 }; 648 649 static int 650 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i, 651 struct ext4_xattr_block_find *bs) 652 { 653 struct super_block *sb = inode->i_sb; 654 int error; 655 656 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", 657 i->name_index, i->name, i->value, (long)i->value_len); 658 659 if (EXT4_I(inode)->i_file_acl) { 660 /* The inode already has an extended attribute block. */ 661 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl); 662 error = -EIO; 663 if (!bs->bh) 664 goto cleanup; 665 ea_bdebug(bs->bh, "b_count=%d, refcount=%d", 666 atomic_read(&(bs->bh->b_count)), 667 le32_to_cpu(BHDR(bs->bh)->h_refcount)); 668 if (ext4_xattr_check_block(bs->bh)) { 669 ext4_error(sb, "inode %lu: bad block %llu", 670 inode->i_ino, EXT4_I(inode)->i_file_acl); 671 error = -EIO; 672 goto cleanup; 673 } 674 /* Find the named attribute. */ 675 bs->s.base = BHDR(bs->bh); 676 bs->s.first = BFIRST(bs->bh); 677 bs->s.end = bs->bh->b_data + bs->bh->b_size; 678 bs->s.here = bs->s.first; 679 error = ext4_xattr_find_entry(&bs->s.here, i->name_index, 680 i->name, bs->bh->b_size, 1); 681 if (error && error != -ENODATA) 682 goto cleanup; 683 bs->s.not_found = error; 684 } 685 error = 0; 686 687 cleanup: 688 return error; 689 } 690 691 static int 692 ext4_xattr_block_set(handle_t *handle, struct inode *inode, 693 struct ext4_xattr_info *i, 694 struct ext4_xattr_block_find *bs) 695 { 696 struct super_block *sb = inode->i_sb; 697 struct buffer_head *new_bh = NULL; 698 struct ext4_xattr_search *s = &bs->s; 699 struct mb_cache_entry *ce = NULL; 700 int error = 0; 701 702 #define header(x) ((struct ext4_xattr_header *)(x)) 703 704 if (i->value && i->value_len > sb->s_blocksize) 705 return -ENOSPC; 706 if (s->base) { 707 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev, 708 bs->bh->b_blocknr); 709 error = ext4_journal_get_write_access(handle, bs->bh); 710 if (error) 711 goto cleanup; 712 lock_buffer(bs->bh); 713 714 if (header(s->base)->h_refcount == cpu_to_le32(1)) { 715 if (ce) { 716 mb_cache_entry_free(ce); 717 ce = NULL; 718 } 719 ea_bdebug(bs->bh, "modifying in-place"); 720 error = ext4_xattr_set_entry(i, s); 721 if (!error) { 722 if (!IS_LAST_ENTRY(s->first)) 723 ext4_xattr_rehash(header(s->base), 724 s->here); 725 ext4_xattr_cache_insert(bs->bh); 726 } 727 unlock_buffer(bs->bh); 728 if (error == -EIO) 729 goto bad_block; 730 if (!error) 731 error = ext4_handle_dirty_metadata(handle, 732 inode, 733 bs->bh); 734 if (error) 735 goto cleanup; 736 goto inserted; 737 } else { 738 int offset = (char *)s->here - bs->bh->b_data; 739 740 unlock_buffer(bs->bh); 741 jbd2_journal_release_buffer(handle, bs->bh); 742 if (ce) { 743 mb_cache_entry_release(ce); 744 ce = NULL; 745 } 746 ea_bdebug(bs->bh, "cloning"); 747 s->base = kmalloc(bs->bh->b_size, GFP_NOFS); 748 error = -ENOMEM; 749 if (s->base == NULL) 750 goto cleanup; 751 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size); 752 s->first = ENTRY(header(s->base)+1); 753 header(s->base)->h_refcount = cpu_to_le32(1); 754 s->here = ENTRY(s->base + offset); 755 s->end = s->base + bs->bh->b_size; 756 } 757 } else { 758 /* Allocate a buffer where we construct the new block. */ 759 s->base = kzalloc(sb->s_blocksize, GFP_NOFS); 760 /* assert(header == s->base) */ 761 error = -ENOMEM; 762 if (s->base == NULL) 763 goto cleanup; 764 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 765 header(s->base)->h_blocks = cpu_to_le32(1); 766 header(s->base)->h_refcount = cpu_to_le32(1); 767 s->first = ENTRY(header(s->base)+1); 768 s->here = ENTRY(header(s->base)+1); 769 s->end = s->base + sb->s_blocksize; 770 } 771 772 error = ext4_xattr_set_entry(i, s); 773 if (error == -EIO) 774 goto bad_block; 775 if (error) 776 goto cleanup; 777 if (!IS_LAST_ENTRY(s->first)) 778 ext4_xattr_rehash(header(s->base), s->here); 779 780 inserted: 781 if (!IS_LAST_ENTRY(s->first)) { 782 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce); 783 if (new_bh) { 784 /* We found an identical block in the cache. */ 785 if (new_bh == bs->bh) 786 ea_bdebug(new_bh, "keeping"); 787 else { 788 /* The old block is released after updating 789 the inode. */ 790 error = dquot_alloc_block(inode, 1); 791 if (error) 792 goto cleanup; 793 error = ext4_journal_get_write_access(handle, 794 new_bh); 795 if (error) 796 goto cleanup_dquot; 797 lock_buffer(new_bh); 798 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1); 799 ea_bdebug(new_bh, "reusing; refcount now=%d", 800 le32_to_cpu(BHDR(new_bh)->h_refcount)); 801 unlock_buffer(new_bh); 802 error = ext4_handle_dirty_metadata(handle, 803 inode, 804 new_bh); 805 if (error) 806 goto cleanup_dquot; 807 } 808 mb_cache_entry_release(ce); 809 ce = NULL; 810 } else if (bs->bh && s->base == bs->bh->b_data) { 811 /* We were modifying this block in-place. */ 812 ea_bdebug(bs->bh, "keeping this block"); 813 new_bh = bs->bh; 814 get_bh(new_bh); 815 } else { 816 /* We need to allocate a new block */ 817 ext4_fsblk_t goal, block; 818 819 goal = ext4_group_first_block_no(sb, 820 EXT4_I(inode)->i_block_group); 821 822 /* non-extent files can't have physical blocks past 2^32 */ 823 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 824 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS; 825 826 block = ext4_new_meta_blocks(handle, inode, 827 goal, NULL, &error); 828 if (error) 829 goto cleanup; 830 831 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 832 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS); 833 834 ea_idebug(inode, "creating block %d", block); 835 836 new_bh = sb_getblk(sb, block); 837 if (!new_bh) { 838 getblk_failed: 839 ext4_free_blocks(handle, inode, 0, block, 1, 840 EXT4_FREE_BLOCKS_METADATA); 841 error = -EIO; 842 goto cleanup; 843 } 844 lock_buffer(new_bh); 845 error = ext4_journal_get_create_access(handle, new_bh); 846 if (error) { 847 unlock_buffer(new_bh); 848 goto getblk_failed; 849 } 850 memcpy(new_bh->b_data, s->base, new_bh->b_size); 851 set_buffer_uptodate(new_bh); 852 unlock_buffer(new_bh); 853 ext4_xattr_cache_insert(new_bh); 854 error = ext4_handle_dirty_metadata(handle, 855 inode, new_bh); 856 if (error) 857 goto cleanup; 858 } 859 } 860 861 /* Update the inode. */ 862 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; 863 864 /* Drop the previous xattr block. */ 865 if (bs->bh && bs->bh != new_bh) 866 ext4_xattr_release_block(handle, inode, bs->bh); 867 error = 0; 868 869 cleanup: 870 if (ce) 871 mb_cache_entry_release(ce); 872 brelse(new_bh); 873 if (!(bs->bh && s->base == bs->bh->b_data)) 874 kfree(s->base); 875 876 return error; 877 878 cleanup_dquot: 879 dquot_free_block(inode, 1); 880 goto cleanup; 881 882 bad_block: 883 ext4_error(inode->i_sb, "inode %lu: bad block %llu", 884 inode->i_ino, EXT4_I(inode)->i_file_acl); 885 goto cleanup; 886 887 #undef header 888 } 889 890 struct ext4_xattr_ibody_find { 891 struct ext4_xattr_search s; 892 struct ext4_iloc iloc; 893 }; 894 895 static int 896 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, 897 struct ext4_xattr_ibody_find *is) 898 { 899 struct ext4_xattr_ibody_header *header; 900 struct ext4_inode *raw_inode; 901 int error; 902 903 if (EXT4_I(inode)->i_extra_isize == 0) 904 return 0; 905 raw_inode = ext4_raw_inode(&is->iloc); 906 header = IHDR(inode, raw_inode); 907 is->s.base = is->s.first = IFIRST(header); 908 is->s.here = is->s.first; 909 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 910 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { 911 error = ext4_xattr_check_names(IFIRST(header), is->s.end); 912 if (error) 913 return error; 914 /* Find the named attribute. */ 915 error = ext4_xattr_find_entry(&is->s.here, i->name_index, 916 i->name, is->s.end - 917 (void *)is->s.base, 0); 918 if (error && error != -ENODATA) 919 return error; 920 is->s.not_found = error; 921 } 922 return 0; 923 } 924 925 static int 926 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode, 927 struct ext4_xattr_info *i, 928 struct ext4_xattr_ibody_find *is) 929 { 930 struct ext4_xattr_ibody_header *header; 931 struct ext4_xattr_search *s = &is->s; 932 int error; 933 934 if (EXT4_I(inode)->i_extra_isize == 0) 935 return -ENOSPC; 936 error = ext4_xattr_set_entry(i, s); 937 if (error) 938 return error; 939 header = IHDR(inode, ext4_raw_inode(&is->iloc)); 940 if (!IS_LAST_ENTRY(s->first)) { 941 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 942 ext4_set_inode_state(inode, EXT4_STATE_XATTR); 943 } else { 944 header->h_magic = cpu_to_le32(0); 945 ext4_clear_inode_state(inode, EXT4_STATE_XATTR); 946 } 947 return 0; 948 } 949 950 /* 951 * ext4_xattr_set_handle() 952 * 953 * Create, replace or remove an extended attribute for this inode. Buffer 954 * is NULL to remove an existing extended attribute, and non-NULL to 955 * either replace an existing extended attribute, or create a new extended 956 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 957 * specify that an extended attribute must exist and must not exist 958 * previous to the call, respectively. 959 * 960 * Returns 0, or a negative error number on failure. 961 */ 962 int 963 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, 964 const char *name, const void *value, size_t value_len, 965 int flags) 966 { 967 struct ext4_xattr_info i = { 968 .name_index = name_index, 969 .name = name, 970 .value = value, 971 .value_len = value_len, 972 973 }; 974 struct ext4_xattr_ibody_find is = { 975 .s = { .not_found = -ENODATA, }, 976 }; 977 struct ext4_xattr_block_find bs = { 978 .s = { .not_found = -ENODATA, }, 979 }; 980 unsigned long no_expand; 981 int error; 982 983 if (!name) 984 return -EINVAL; 985 if (strlen(name) > 255) 986 return -ERANGE; 987 down_write(&EXT4_I(inode)->xattr_sem); 988 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND); 989 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); 990 991 error = ext4_get_inode_loc(inode, &is.iloc); 992 if (error) 993 goto cleanup; 994 995 error = ext4_journal_get_write_access(handle, is.iloc.bh); 996 if (error) 997 goto cleanup; 998 999 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) { 1000 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc); 1001 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); 1002 ext4_clear_inode_state(inode, EXT4_STATE_NEW); 1003 } 1004 1005 error = ext4_xattr_ibody_find(inode, &i, &is); 1006 if (error) 1007 goto cleanup; 1008 if (is.s.not_found) 1009 error = ext4_xattr_block_find(inode, &i, &bs); 1010 if (error) 1011 goto cleanup; 1012 if (is.s.not_found && bs.s.not_found) { 1013 error = -ENODATA; 1014 if (flags & XATTR_REPLACE) 1015 goto cleanup; 1016 error = 0; 1017 if (!value) 1018 goto cleanup; 1019 } else { 1020 error = -EEXIST; 1021 if (flags & XATTR_CREATE) 1022 goto cleanup; 1023 } 1024 if (!value) { 1025 if (!is.s.not_found) 1026 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1027 else if (!bs.s.not_found) 1028 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1029 } else { 1030 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1031 if (!error && !bs.s.not_found) { 1032 i.value = NULL; 1033 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1034 } else if (error == -ENOSPC) { 1035 if (EXT4_I(inode)->i_file_acl && !bs.s.base) { 1036 error = ext4_xattr_block_find(inode, &i, &bs); 1037 if (error) 1038 goto cleanup; 1039 } 1040 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1041 if (error) 1042 goto cleanup; 1043 if (!is.s.not_found) { 1044 i.value = NULL; 1045 error = ext4_xattr_ibody_set(handle, inode, &i, 1046 &is); 1047 } 1048 } 1049 } 1050 if (!error) { 1051 ext4_xattr_update_super_block(handle, inode->i_sb); 1052 inode->i_ctime = ext4_current_time(inode); 1053 if (!value) 1054 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); 1055 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc); 1056 /* 1057 * The bh is consumed by ext4_mark_iloc_dirty, even with 1058 * error != 0. 1059 */ 1060 is.iloc.bh = NULL; 1061 if (IS_SYNC(inode)) 1062 ext4_handle_sync(handle); 1063 } 1064 1065 cleanup: 1066 brelse(is.iloc.bh); 1067 brelse(bs.bh); 1068 if (no_expand == 0) 1069 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); 1070 up_write(&EXT4_I(inode)->xattr_sem); 1071 return error; 1072 } 1073 1074 /* 1075 * ext4_xattr_set() 1076 * 1077 * Like ext4_xattr_set_handle, but start from an inode. This extended 1078 * attribute modification is a filesystem transaction by itself. 1079 * 1080 * Returns 0, or a negative error number on failure. 1081 */ 1082 int 1083 ext4_xattr_set(struct inode *inode, int name_index, const char *name, 1084 const void *value, size_t value_len, int flags) 1085 { 1086 handle_t *handle; 1087 int error, retries = 0; 1088 1089 retry: 1090 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb)); 1091 if (IS_ERR(handle)) { 1092 error = PTR_ERR(handle); 1093 } else { 1094 int error2; 1095 1096 error = ext4_xattr_set_handle(handle, inode, name_index, name, 1097 value, value_len, flags); 1098 error2 = ext4_journal_stop(handle); 1099 if (error == -ENOSPC && 1100 ext4_should_retry_alloc(inode->i_sb, &retries)) 1101 goto retry; 1102 if (error == 0) 1103 error = error2; 1104 } 1105 1106 return error; 1107 } 1108 1109 /* 1110 * Shift the EA entries in the inode to create space for the increased 1111 * i_extra_isize. 1112 */ 1113 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry, 1114 int value_offs_shift, void *to, 1115 void *from, size_t n, int blocksize) 1116 { 1117 struct ext4_xattr_entry *last = entry; 1118 int new_offs; 1119 1120 /* Adjust the value offsets of the entries */ 1121 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1122 if (!last->e_value_block && last->e_value_size) { 1123 new_offs = le16_to_cpu(last->e_value_offs) + 1124 value_offs_shift; 1125 BUG_ON(new_offs + le32_to_cpu(last->e_value_size) 1126 > blocksize); 1127 last->e_value_offs = cpu_to_le16(new_offs); 1128 } 1129 } 1130 /* Shift the entries by n bytes */ 1131 memmove(to, from, n); 1132 } 1133 1134 /* 1135 * Expand an inode by new_extra_isize bytes when EAs are present. 1136 * Returns 0 on success or negative error number on failure. 1137 */ 1138 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, 1139 struct ext4_inode *raw_inode, handle_t *handle) 1140 { 1141 struct ext4_xattr_ibody_header *header; 1142 struct ext4_xattr_entry *entry, *last, *first; 1143 struct buffer_head *bh = NULL; 1144 struct ext4_xattr_ibody_find *is = NULL; 1145 struct ext4_xattr_block_find *bs = NULL; 1146 char *buffer = NULL, *b_entry_name = NULL; 1147 size_t min_offs, free; 1148 int total_ino, total_blk; 1149 void *base, *start, *end; 1150 int extra_isize = 0, error = 0, tried_min_extra_isize = 0; 1151 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize); 1152 1153 down_write(&EXT4_I(inode)->xattr_sem); 1154 retry: 1155 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) { 1156 up_write(&EXT4_I(inode)->xattr_sem); 1157 return 0; 1158 } 1159 1160 header = IHDR(inode, raw_inode); 1161 entry = IFIRST(header); 1162 1163 /* 1164 * Check if enough free space is available in the inode to shift the 1165 * entries ahead by new_extra_isize. 1166 */ 1167 1168 base = start = entry; 1169 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 1170 min_offs = end - base; 1171 last = entry; 1172 total_ino = sizeof(struct ext4_xattr_ibody_header); 1173 1174 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino); 1175 if (free >= new_extra_isize) { 1176 entry = IFIRST(header); 1177 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize 1178 - new_extra_isize, (void *)raw_inode + 1179 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize, 1180 (void *)header, total_ino, 1181 inode->i_sb->s_blocksize); 1182 EXT4_I(inode)->i_extra_isize = new_extra_isize; 1183 error = 0; 1184 goto cleanup; 1185 } 1186 1187 /* 1188 * Enough free space isn't available in the inode, check if 1189 * EA block can hold new_extra_isize bytes. 1190 */ 1191 if (EXT4_I(inode)->i_file_acl) { 1192 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1193 error = -EIO; 1194 if (!bh) 1195 goto cleanup; 1196 if (ext4_xattr_check_block(bh)) { 1197 ext4_error(inode->i_sb, "inode %lu: bad block %llu", 1198 inode->i_ino, EXT4_I(inode)->i_file_acl); 1199 error = -EIO; 1200 goto cleanup; 1201 } 1202 base = BHDR(bh); 1203 first = BFIRST(bh); 1204 end = bh->b_data + bh->b_size; 1205 min_offs = end - base; 1206 free = ext4_xattr_free_space(first, &min_offs, base, 1207 &total_blk); 1208 if (free < new_extra_isize) { 1209 if (!tried_min_extra_isize && s_min_extra_isize) { 1210 tried_min_extra_isize++; 1211 new_extra_isize = s_min_extra_isize; 1212 brelse(bh); 1213 goto retry; 1214 } 1215 error = -1; 1216 goto cleanup; 1217 } 1218 } else { 1219 free = inode->i_sb->s_blocksize; 1220 } 1221 1222 while (new_extra_isize > 0) { 1223 size_t offs, size, entry_size; 1224 struct ext4_xattr_entry *small_entry = NULL; 1225 struct ext4_xattr_info i = { 1226 .value = NULL, 1227 .value_len = 0, 1228 }; 1229 unsigned int total_size; /* EA entry size + value size */ 1230 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */ 1231 unsigned int min_total_size = ~0U; 1232 1233 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS); 1234 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS); 1235 if (!is || !bs) { 1236 error = -ENOMEM; 1237 goto cleanup; 1238 } 1239 1240 is->s.not_found = -ENODATA; 1241 bs->s.not_found = -ENODATA; 1242 is->iloc.bh = NULL; 1243 bs->bh = NULL; 1244 1245 last = IFIRST(header); 1246 /* Find the entry best suited to be pushed into EA block */ 1247 entry = NULL; 1248 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1249 total_size = 1250 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) + 1251 EXT4_XATTR_LEN(last->e_name_len); 1252 if (total_size <= free && total_size < min_total_size) { 1253 if (total_size < new_extra_isize) { 1254 small_entry = last; 1255 } else { 1256 entry = last; 1257 min_total_size = total_size; 1258 } 1259 } 1260 } 1261 1262 if (entry == NULL) { 1263 if (small_entry) { 1264 entry = small_entry; 1265 } else { 1266 if (!tried_min_extra_isize && 1267 s_min_extra_isize) { 1268 tried_min_extra_isize++; 1269 new_extra_isize = s_min_extra_isize; 1270 goto retry; 1271 } 1272 error = -1; 1273 goto cleanup; 1274 } 1275 } 1276 offs = le16_to_cpu(entry->e_value_offs); 1277 size = le32_to_cpu(entry->e_value_size); 1278 entry_size = EXT4_XATTR_LEN(entry->e_name_len); 1279 i.name_index = entry->e_name_index, 1280 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS); 1281 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS); 1282 if (!buffer || !b_entry_name) { 1283 error = -ENOMEM; 1284 goto cleanup; 1285 } 1286 /* Save the entry name and the entry value */ 1287 memcpy(buffer, (void *)IFIRST(header) + offs, 1288 EXT4_XATTR_SIZE(size)); 1289 memcpy(b_entry_name, entry->e_name, entry->e_name_len); 1290 b_entry_name[entry->e_name_len] = '\0'; 1291 i.name = b_entry_name; 1292 1293 error = ext4_get_inode_loc(inode, &is->iloc); 1294 if (error) 1295 goto cleanup; 1296 1297 error = ext4_xattr_ibody_find(inode, &i, is); 1298 if (error) 1299 goto cleanup; 1300 1301 /* Remove the chosen entry from the inode */ 1302 error = ext4_xattr_ibody_set(handle, inode, &i, is); 1303 if (error) 1304 goto cleanup; 1305 1306 entry = IFIRST(header); 1307 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize) 1308 shift_bytes = new_extra_isize; 1309 else 1310 shift_bytes = entry_size + size; 1311 /* Adjust the offsets and shift the remaining entries ahead */ 1312 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize - 1313 shift_bytes, (void *)raw_inode + 1314 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes, 1315 (void *)header, total_ino - entry_size, 1316 inode->i_sb->s_blocksize); 1317 1318 extra_isize += shift_bytes; 1319 new_extra_isize -= shift_bytes; 1320 EXT4_I(inode)->i_extra_isize = extra_isize; 1321 1322 i.name = b_entry_name; 1323 i.value = buffer; 1324 i.value_len = size; 1325 error = ext4_xattr_block_find(inode, &i, bs); 1326 if (error) 1327 goto cleanup; 1328 1329 /* Add entry which was removed from the inode into the block */ 1330 error = ext4_xattr_block_set(handle, inode, &i, bs); 1331 if (error) 1332 goto cleanup; 1333 kfree(b_entry_name); 1334 kfree(buffer); 1335 b_entry_name = NULL; 1336 buffer = NULL; 1337 brelse(is->iloc.bh); 1338 kfree(is); 1339 kfree(bs); 1340 } 1341 brelse(bh); 1342 up_write(&EXT4_I(inode)->xattr_sem); 1343 return 0; 1344 1345 cleanup: 1346 kfree(b_entry_name); 1347 kfree(buffer); 1348 if (is) 1349 brelse(is->iloc.bh); 1350 kfree(is); 1351 kfree(bs); 1352 brelse(bh); 1353 up_write(&EXT4_I(inode)->xattr_sem); 1354 return error; 1355 } 1356 1357 1358 1359 /* 1360 * ext4_xattr_delete_inode() 1361 * 1362 * Free extended attribute resources associated with this inode. This 1363 * is called immediately before an inode is freed. We have exclusive 1364 * access to the inode. 1365 */ 1366 void 1367 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode) 1368 { 1369 struct buffer_head *bh = NULL; 1370 1371 if (!EXT4_I(inode)->i_file_acl) 1372 goto cleanup; 1373 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1374 if (!bh) { 1375 ext4_error(inode->i_sb, "inode %lu: block %llu read error", 1376 inode->i_ino, EXT4_I(inode)->i_file_acl); 1377 goto cleanup; 1378 } 1379 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 1380 BHDR(bh)->h_blocks != cpu_to_le32(1)) { 1381 ext4_error(inode->i_sb, "inode %lu: bad block %llu", 1382 inode->i_ino, EXT4_I(inode)->i_file_acl); 1383 goto cleanup; 1384 } 1385 ext4_xattr_release_block(handle, inode, bh); 1386 EXT4_I(inode)->i_file_acl = 0; 1387 1388 cleanup: 1389 brelse(bh); 1390 } 1391 1392 /* 1393 * ext4_xattr_put_super() 1394 * 1395 * This is called when a file system is unmounted. 1396 */ 1397 void 1398 ext4_xattr_put_super(struct super_block *sb) 1399 { 1400 mb_cache_shrink(sb->s_bdev); 1401 } 1402 1403 /* 1404 * ext4_xattr_cache_insert() 1405 * 1406 * Create a new entry in the extended attribute cache, and insert 1407 * it unless such an entry is already in the cache. 1408 * 1409 * Returns 0, or a negative error number on failure. 1410 */ 1411 static void 1412 ext4_xattr_cache_insert(struct buffer_head *bh) 1413 { 1414 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash); 1415 struct mb_cache_entry *ce; 1416 int error; 1417 1418 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS); 1419 if (!ce) { 1420 ea_bdebug(bh, "out of memory"); 1421 return; 1422 } 1423 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash); 1424 if (error) { 1425 mb_cache_entry_free(ce); 1426 if (error == -EBUSY) { 1427 ea_bdebug(bh, "already in cache"); 1428 error = 0; 1429 } 1430 } else { 1431 ea_bdebug(bh, "inserting [%x]", (int)hash); 1432 mb_cache_entry_release(ce); 1433 } 1434 } 1435 1436 /* 1437 * ext4_xattr_cmp() 1438 * 1439 * Compare two extended attribute blocks for equality. 1440 * 1441 * Returns 0 if the blocks are equal, 1 if they differ, and 1442 * a negative error number on errors. 1443 */ 1444 static int 1445 ext4_xattr_cmp(struct ext4_xattr_header *header1, 1446 struct ext4_xattr_header *header2) 1447 { 1448 struct ext4_xattr_entry *entry1, *entry2; 1449 1450 entry1 = ENTRY(header1+1); 1451 entry2 = ENTRY(header2+1); 1452 while (!IS_LAST_ENTRY(entry1)) { 1453 if (IS_LAST_ENTRY(entry2)) 1454 return 1; 1455 if (entry1->e_hash != entry2->e_hash || 1456 entry1->e_name_index != entry2->e_name_index || 1457 entry1->e_name_len != entry2->e_name_len || 1458 entry1->e_value_size != entry2->e_value_size || 1459 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) 1460 return 1; 1461 if (entry1->e_value_block != 0 || entry2->e_value_block != 0) 1462 return -EIO; 1463 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), 1464 (char *)header2 + le16_to_cpu(entry2->e_value_offs), 1465 le32_to_cpu(entry1->e_value_size))) 1466 return 1; 1467 1468 entry1 = EXT4_XATTR_NEXT(entry1); 1469 entry2 = EXT4_XATTR_NEXT(entry2); 1470 } 1471 if (!IS_LAST_ENTRY(entry2)) 1472 return 1; 1473 return 0; 1474 } 1475 1476 /* 1477 * ext4_xattr_cache_find() 1478 * 1479 * Find an identical extended attribute block. 1480 * 1481 * Returns a pointer to the block found, or NULL if such a block was 1482 * not found or an error occurred. 1483 */ 1484 static struct buffer_head * 1485 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header, 1486 struct mb_cache_entry **pce) 1487 { 1488 __u32 hash = le32_to_cpu(header->h_hash); 1489 struct mb_cache_entry *ce; 1490 1491 if (!header->h_hash) 1492 return NULL; /* never share */ 1493 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); 1494 again: 1495 ce = mb_cache_entry_find_first(ext4_xattr_cache, 0, 1496 inode->i_sb->s_bdev, hash); 1497 while (ce) { 1498 struct buffer_head *bh; 1499 1500 if (IS_ERR(ce)) { 1501 if (PTR_ERR(ce) == -EAGAIN) 1502 goto again; 1503 break; 1504 } 1505 bh = sb_bread(inode->i_sb, ce->e_block); 1506 if (!bh) { 1507 ext4_error(inode->i_sb, 1508 "inode %lu: block %lu read error", 1509 inode->i_ino, (unsigned long) ce->e_block); 1510 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >= 1511 EXT4_XATTR_REFCOUNT_MAX) { 1512 ea_idebug(inode, "block %lu refcount %d>=%d", 1513 (unsigned long) ce->e_block, 1514 le32_to_cpu(BHDR(bh)->h_refcount), 1515 EXT4_XATTR_REFCOUNT_MAX); 1516 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) { 1517 *pce = ce; 1518 return bh; 1519 } 1520 brelse(bh); 1521 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash); 1522 } 1523 return NULL; 1524 } 1525 1526 #define NAME_HASH_SHIFT 5 1527 #define VALUE_HASH_SHIFT 16 1528 1529 /* 1530 * ext4_xattr_hash_entry() 1531 * 1532 * Compute the hash of an extended attribute. 1533 */ 1534 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header, 1535 struct ext4_xattr_entry *entry) 1536 { 1537 __u32 hash = 0; 1538 char *name = entry->e_name; 1539 int n; 1540 1541 for (n = 0; n < entry->e_name_len; n++) { 1542 hash = (hash << NAME_HASH_SHIFT) ^ 1543 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ 1544 *name++; 1545 } 1546 1547 if (entry->e_value_block == 0 && entry->e_value_size != 0) { 1548 __le32 *value = (__le32 *)((char *)header + 1549 le16_to_cpu(entry->e_value_offs)); 1550 for (n = (le32_to_cpu(entry->e_value_size) + 1551 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) { 1552 hash = (hash << VALUE_HASH_SHIFT) ^ 1553 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ 1554 le32_to_cpu(*value++); 1555 } 1556 } 1557 entry->e_hash = cpu_to_le32(hash); 1558 } 1559 1560 #undef NAME_HASH_SHIFT 1561 #undef VALUE_HASH_SHIFT 1562 1563 #define BLOCK_HASH_SHIFT 16 1564 1565 /* 1566 * ext4_xattr_rehash() 1567 * 1568 * Re-compute the extended attribute hash value after an entry has changed. 1569 */ 1570 static void ext4_xattr_rehash(struct ext4_xattr_header *header, 1571 struct ext4_xattr_entry *entry) 1572 { 1573 struct ext4_xattr_entry *here; 1574 __u32 hash = 0; 1575 1576 ext4_xattr_hash_entry(header, entry); 1577 here = ENTRY(header+1); 1578 while (!IS_LAST_ENTRY(here)) { 1579 if (!here->e_hash) { 1580 /* Block is not shared if an entry's hash value == 0 */ 1581 hash = 0; 1582 break; 1583 } 1584 hash = (hash << BLOCK_HASH_SHIFT) ^ 1585 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ 1586 le32_to_cpu(here->e_hash); 1587 here = EXT4_XATTR_NEXT(here); 1588 } 1589 header->h_hash = cpu_to_le32(hash); 1590 } 1591 1592 #undef BLOCK_HASH_SHIFT 1593 1594 int __init 1595 init_ext4_xattr(void) 1596 { 1597 ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL, 1598 sizeof(struct mb_cache_entry) + 1599 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6); 1600 if (!ext4_xattr_cache) 1601 return -ENOMEM; 1602 return 0; 1603 } 1604 1605 void 1606 exit_ext4_xattr(void) 1607 { 1608 if (ext4_xattr_cache) 1609 mb_cache_destroy(ext4_xattr_cache); 1610 ext4_xattr_cache = NULL; 1611 } 1612