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 #ifdef EXT4_XATTR_DEBUG 65 # define ea_idebug(inode, f...) do { \ 66 printk(KERN_DEBUG "inode %s:%lu: ", \ 67 inode->i_sb->s_id, inode->i_ino); \ 68 printk(f); \ 69 printk("\n"); \ 70 } while (0) 71 # define ea_bdebug(bh, f...) do { \ 72 char b[BDEVNAME_SIZE]; \ 73 printk(KERN_DEBUG "block %s:%lu: ", \ 74 bdevname(bh->b_bdev, b), \ 75 (unsigned long) bh->b_blocknr); \ 76 printk(f); \ 77 printk("\n"); \ 78 } while (0) 79 #else 80 # define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__) 81 # define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__) 82 #endif 83 84 static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *); 85 static struct buffer_head *ext4_xattr_cache_find(struct inode *, 86 struct ext4_xattr_header *, 87 struct mb_cache_entry **); 88 static void ext4_xattr_rehash(struct ext4_xattr_header *, 89 struct ext4_xattr_entry *); 90 static int ext4_xattr_list(struct dentry *dentry, char *buffer, 91 size_t buffer_size); 92 93 static const struct xattr_handler *ext4_xattr_handler_map[] = { 94 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler, 95 #ifdef CONFIG_EXT4_FS_POSIX_ACL 96 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler, 97 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler, 98 #endif 99 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler, 100 #ifdef CONFIG_EXT4_FS_SECURITY 101 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler, 102 #endif 103 }; 104 105 const struct xattr_handler *ext4_xattr_handlers[] = { 106 &ext4_xattr_user_handler, 107 &ext4_xattr_trusted_handler, 108 #ifdef CONFIG_EXT4_FS_POSIX_ACL 109 &posix_acl_access_xattr_handler, 110 &posix_acl_default_xattr_handler, 111 #endif 112 #ifdef CONFIG_EXT4_FS_SECURITY 113 &ext4_xattr_security_handler, 114 #endif 115 NULL 116 }; 117 118 #define EXT4_GET_MB_CACHE(inode) (((struct ext4_sb_info *) \ 119 inode->i_sb->s_fs_info)->s_mb_cache) 120 121 static __le32 ext4_xattr_block_csum(struct inode *inode, 122 sector_t block_nr, 123 struct ext4_xattr_header *hdr) 124 { 125 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 126 __u32 csum; 127 __le32 save_csum; 128 __le64 dsk_block_nr = cpu_to_le64(block_nr); 129 130 save_csum = hdr->h_checksum; 131 hdr->h_checksum = 0; 132 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr, 133 sizeof(dsk_block_nr)); 134 csum = ext4_chksum(sbi, csum, (__u8 *)hdr, 135 EXT4_BLOCK_SIZE(inode->i_sb)); 136 137 hdr->h_checksum = save_csum; 138 return cpu_to_le32(csum); 139 } 140 141 static int ext4_xattr_block_csum_verify(struct inode *inode, 142 sector_t block_nr, 143 struct ext4_xattr_header *hdr) 144 { 145 if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, 146 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) && 147 (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr))) 148 return 0; 149 return 1; 150 } 151 152 static void ext4_xattr_block_csum_set(struct inode *inode, 153 sector_t block_nr, 154 struct ext4_xattr_header *hdr) 155 { 156 if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, 157 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) 158 return; 159 160 hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr); 161 } 162 163 static inline int ext4_handle_dirty_xattr_block(handle_t *handle, 164 struct inode *inode, 165 struct buffer_head *bh) 166 { 167 ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh)); 168 return ext4_handle_dirty_metadata(handle, inode, bh); 169 } 170 171 static inline const struct xattr_handler * 172 ext4_xattr_handler(int name_index) 173 { 174 const struct xattr_handler *handler = NULL; 175 176 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map)) 177 handler = ext4_xattr_handler_map[name_index]; 178 return handler; 179 } 180 181 /* 182 * Inode operation listxattr() 183 * 184 * dentry->d_inode->i_mutex: don't care 185 */ 186 ssize_t 187 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size) 188 { 189 return ext4_xattr_list(dentry, buffer, size); 190 } 191 192 static int 193 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end) 194 { 195 while (!IS_LAST_ENTRY(entry)) { 196 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry); 197 if ((void *)next >= end) 198 return -EIO; 199 entry = next; 200 } 201 return 0; 202 } 203 204 static inline int 205 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh) 206 { 207 int error; 208 209 if (buffer_verified(bh)) 210 return 0; 211 212 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 213 BHDR(bh)->h_blocks != cpu_to_le32(1)) 214 return -EIO; 215 if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh))) 216 return -EIO; 217 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size); 218 if (!error) 219 set_buffer_verified(bh); 220 return error; 221 } 222 223 static inline int 224 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size) 225 { 226 size_t value_size = le32_to_cpu(entry->e_value_size); 227 228 if (entry->e_value_block != 0 || value_size > size || 229 le16_to_cpu(entry->e_value_offs) + value_size > size) 230 return -EIO; 231 return 0; 232 } 233 234 static int 235 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index, 236 const char *name, size_t size, int sorted) 237 { 238 struct ext4_xattr_entry *entry; 239 size_t name_len; 240 int cmp = 1; 241 242 if (name == NULL) 243 return -EINVAL; 244 name_len = strlen(name); 245 entry = *pentry; 246 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 247 cmp = name_index - entry->e_name_index; 248 if (!cmp) 249 cmp = name_len - entry->e_name_len; 250 if (!cmp) 251 cmp = memcmp(name, entry->e_name, name_len); 252 if (cmp <= 0 && (sorted || cmp == 0)) 253 break; 254 } 255 *pentry = entry; 256 if (!cmp && ext4_xattr_check_entry(entry, size)) 257 return -EIO; 258 return cmp ? -ENODATA : 0; 259 } 260 261 static int 262 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name, 263 void *buffer, size_t buffer_size) 264 { 265 struct buffer_head *bh = NULL; 266 struct ext4_xattr_entry *entry; 267 size_t size; 268 int error; 269 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 270 271 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", 272 name_index, name, buffer, (long)buffer_size); 273 274 error = -ENODATA; 275 if (!EXT4_I(inode)->i_file_acl) 276 goto cleanup; 277 ea_idebug(inode, "reading block %llu", 278 (unsigned long long)EXT4_I(inode)->i_file_acl); 279 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 280 if (!bh) 281 goto cleanup; 282 ea_bdebug(bh, "b_count=%d, refcount=%d", 283 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 284 if (ext4_xattr_check_block(inode, bh)) { 285 bad_block: 286 EXT4_ERROR_INODE(inode, "bad block %llu", 287 EXT4_I(inode)->i_file_acl); 288 error = -EIO; 289 goto cleanup; 290 } 291 ext4_xattr_cache_insert(ext4_mb_cache, bh); 292 entry = BFIRST(bh); 293 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1); 294 if (error == -EIO) 295 goto bad_block; 296 if (error) 297 goto cleanup; 298 size = le32_to_cpu(entry->e_value_size); 299 if (buffer) { 300 error = -ERANGE; 301 if (size > buffer_size) 302 goto cleanup; 303 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), 304 size); 305 } 306 error = size; 307 308 cleanup: 309 brelse(bh); 310 return error; 311 } 312 313 int 314 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name, 315 void *buffer, size_t buffer_size) 316 { 317 struct ext4_xattr_ibody_header *header; 318 struct ext4_xattr_entry *entry; 319 struct ext4_inode *raw_inode; 320 struct ext4_iloc iloc; 321 size_t size; 322 void *end; 323 int error; 324 325 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR)) 326 return -ENODATA; 327 error = ext4_get_inode_loc(inode, &iloc); 328 if (error) 329 return error; 330 raw_inode = ext4_raw_inode(&iloc); 331 header = IHDR(inode, raw_inode); 332 entry = IFIRST(header); 333 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 334 error = ext4_xattr_check_names(entry, end); 335 if (error) 336 goto cleanup; 337 error = ext4_xattr_find_entry(&entry, name_index, name, 338 end - (void *)entry, 0); 339 if (error) 340 goto cleanup; 341 size = le32_to_cpu(entry->e_value_size); 342 if (buffer) { 343 error = -ERANGE; 344 if (size > buffer_size) 345 goto cleanup; 346 memcpy(buffer, (void *)IFIRST(header) + 347 le16_to_cpu(entry->e_value_offs), size); 348 } 349 error = size; 350 351 cleanup: 352 brelse(iloc.bh); 353 return error; 354 } 355 356 /* 357 * ext4_xattr_get() 358 * 359 * Copy an extended attribute into the buffer 360 * provided, or compute the buffer size required. 361 * Buffer is NULL to compute the size of the buffer required. 362 * 363 * Returns a negative error number on failure, or the number of bytes 364 * used / required on success. 365 */ 366 int 367 ext4_xattr_get(struct inode *inode, int name_index, const char *name, 368 void *buffer, size_t buffer_size) 369 { 370 int error; 371 372 down_read(&EXT4_I(inode)->xattr_sem); 373 error = ext4_xattr_ibody_get(inode, name_index, name, buffer, 374 buffer_size); 375 if (error == -ENODATA) 376 error = ext4_xattr_block_get(inode, name_index, name, buffer, 377 buffer_size); 378 up_read(&EXT4_I(inode)->xattr_sem); 379 return error; 380 } 381 382 static int 383 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry, 384 char *buffer, size_t buffer_size) 385 { 386 size_t rest = buffer_size; 387 388 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 389 const struct xattr_handler *handler = 390 ext4_xattr_handler(entry->e_name_index); 391 392 if (handler) { 393 size_t size = handler->list(dentry, buffer, rest, 394 entry->e_name, 395 entry->e_name_len, 396 handler->flags); 397 if (buffer) { 398 if (size > rest) 399 return -ERANGE; 400 buffer += size; 401 } 402 rest -= size; 403 } 404 } 405 return buffer_size - rest; 406 } 407 408 static int 409 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size) 410 { 411 struct inode *inode = dentry->d_inode; 412 struct buffer_head *bh = NULL; 413 int error; 414 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 415 416 ea_idebug(inode, "buffer=%p, buffer_size=%ld", 417 buffer, (long)buffer_size); 418 419 error = 0; 420 if (!EXT4_I(inode)->i_file_acl) 421 goto cleanup; 422 ea_idebug(inode, "reading block %llu", 423 (unsigned long long)EXT4_I(inode)->i_file_acl); 424 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 425 error = -EIO; 426 if (!bh) 427 goto cleanup; 428 ea_bdebug(bh, "b_count=%d, refcount=%d", 429 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 430 if (ext4_xattr_check_block(inode, bh)) { 431 EXT4_ERROR_INODE(inode, "bad block %llu", 432 EXT4_I(inode)->i_file_acl); 433 error = -EIO; 434 goto cleanup; 435 } 436 ext4_xattr_cache_insert(ext4_mb_cache, bh); 437 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size); 438 439 cleanup: 440 brelse(bh); 441 442 return error; 443 } 444 445 static int 446 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size) 447 { 448 struct inode *inode = dentry->d_inode; 449 struct ext4_xattr_ibody_header *header; 450 struct ext4_inode *raw_inode; 451 struct ext4_iloc iloc; 452 void *end; 453 int error; 454 455 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR)) 456 return 0; 457 error = ext4_get_inode_loc(inode, &iloc); 458 if (error) 459 return error; 460 raw_inode = ext4_raw_inode(&iloc); 461 header = IHDR(inode, raw_inode); 462 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 463 error = ext4_xattr_check_names(IFIRST(header), end); 464 if (error) 465 goto cleanup; 466 error = ext4_xattr_list_entries(dentry, IFIRST(header), 467 buffer, buffer_size); 468 469 cleanup: 470 brelse(iloc.bh); 471 return error; 472 } 473 474 /* 475 * ext4_xattr_list() 476 * 477 * Copy a list of attribute names into the buffer 478 * provided, or compute the buffer size required. 479 * Buffer is NULL to compute the size of the buffer required. 480 * 481 * Returns a negative error number on failure, or the number of bytes 482 * used / required on success. 483 */ 484 static int 485 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size) 486 { 487 int ret, ret2; 488 489 down_read(&EXT4_I(dentry->d_inode)->xattr_sem); 490 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size); 491 if (ret < 0) 492 goto errout; 493 if (buffer) { 494 buffer += ret; 495 buffer_size -= ret; 496 } 497 ret = ext4_xattr_block_list(dentry, buffer, buffer_size); 498 if (ret < 0) 499 goto errout; 500 ret += ret2; 501 errout: 502 up_read(&EXT4_I(dentry->d_inode)->xattr_sem); 503 return ret; 504 } 505 506 /* 507 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is 508 * not set, set it. 509 */ 510 static void ext4_xattr_update_super_block(handle_t *handle, 511 struct super_block *sb) 512 { 513 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR)) 514 return; 515 516 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) { 517 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR); 518 ext4_handle_dirty_super(handle, sb); 519 } 520 } 521 522 /* 523 * Release the xattr block BH: If the reference count is > 1, decrement it; 524 * otherwise free the block. 525 */ 526 static void 527 ext4_xattr_release_block(handle_t *handle, struct inode *inode, 528 struct buffer_head *bh) 529 { 530 struct mb_cache_entry *ce = NULL; 531 int error = 0; 532 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 533 534 ce = mb_cache_entry_get(ext4_mb_cache, bh->b_bdev, bh->b_blocknr); 535 error = ext4_journal_get_write_access(handle, bh); 536 if (error) 537 goto out; 538 539 lock_buffer(bh); 540 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) { 541 ea_bdebug(bh, "refcount now=0; freeing"); 542 if (ce) 543 mb_cache_entry_free(ce); 544 get_bh(bh); 545 unlock_buffer(bh); 546 ext4_free_blocks(handle, inode, bh, 0, 1, 547 EXT4_FREE_BLOCKS_METADATA | 548 EXT4_FREE_BLOCKS_FORGET); 549 } else { 550 le32_add_cpu(&BHDR(bh)->h_refcount, -1); 551 if (ce) 552 mb_cache_entry_release(ce); 553 /* 554 * Beware of this ugliness: Releasing of xattr block references 555 * from different inodes can race and so we have to protect 556 * from a race where someone else frees the block (and releases 557 * its journal_head) before we are done dirtying the buffer. In 558 * nojournal mode this race is harmless and we actually cannot 559 * call ext4_handle_dirty_xattr_block() with locked buffer as 560 * that function can call sync_dirty_buffer() so for that case 561 * we handle the dirtying after unlocking the buffer. 562 */ 563 if (ext4_handle_valid(handle)) 564 error = ext4_handle_dirty_xattr_block(handle, inode, 565 bh); 566 unlock_buffer(bh); 567 if (!ext4_handle_valid(handle)) 568 error = ext4_handle_dirty_xattr_block(handle, inode, 569 bh); 570 if (IS_SYNC(inode)) 571 ext4_handle_sync(handle); 572 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1)); 573 ea_bdebug(bh, "refcount now=%d; releasing", 574 le32_to_cpu(BHDR(bh)->h_refcount)); 575 } 576 out: 577 ext4_std_error(inode->i_sb, error); 578 return; 579 } 580 581 /* 582 * Find the available free space for EAs. This also returns the total number of 583 * bytes used by EA entries. 584 */ 585 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last, 586 size_t *min_offs, void *base, int *total) 587 { 588 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 589 if (!last->e_value_block && last->e_value_size) { 590 size_t offs = le16_to_cpu(last->e_value_offs); 591 if (offs < *min_offs) 592 *min_offs = offs; 593 } 594 if (total) 595 *total += EXT4_XATTR_LEN(last->e_name_len); 596 } 597 return (*min_offs - ((void *)last - base) - sizeof(__u32)); 598 } 599 600 static int 601 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s) 602 { 603 struct ext4_xattr_entry *last; 604 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name); 605 606 /* Compute min_offs and last. */ 607 last = s->first; 608 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 609 if (!last->e_value_block && last->e_value_size) { 610 size_t offs = le16_to_cpu(last->e_value_offs); 611 if (offs < min_offs) 612 min_offs = offs; 613 } 614 } 615 free = min_offs - ((void *)last - s->base) - sizeof(__u32); 616 if (!s->not_found) { 617 if (!s->here->e_value_block && s->here->e_value_size) { 618 size_t size = le32_to_cpu(s->here->e_value_size); 619 free += EXT4_XATTR_SIZE(size); 620 } 621 free += EXT4_XATTR_LEN(name_len); 622 } 623 if (i->value) { 624 if (free < EXT4_XATTR_SIZE(i->value_len) || 625 free < EXT4_XATTR_LEN(name_len) + 626 EXT4_XATTR_SIZE(i->value_len)) 627 return -ENOSPC; 628 } 629 630 if (i->value && s->not_found) { 631 /* Insert the new name. */ 632 size_t size = EXT4_XATTR_LEN(name_len); 633 size_t rest = (void *)last - (void *)s->here + sizeof(__u32); 634 memmove((void *)s->here + size, s->here, rest); 635 memset(s->here, 0, size); 636 s->here->e_name_index = i->name_index; 637 s->here->e_name_len = name_len; 638 memcpy(s->here->e_name, i->name, name_len); 639 } else { 640 if (!s->here->e_value_block && s->here->e_value_size) { 641 void *first_val = s->base + min_offs; 642 size_t offs = le16_to_cpu(s->here->e_value_offs); 643 void *val = s->base + offs; 644 size_t size = EXT4_XATTR_SIZE( 645 le32_to_cpu(s->here->e_value_size)); 646 647 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) { 648 /* The old and the new value have the same 649 size. Just replace. */ 650 s->here->e_value_size = 651 cpu_to_le32(i->value_len); 652 if (i->value == EXT4_ZERO_XATTR_VALUE) { 653 memset(val, 0, size); 654 } else { 655 /* Clear pad bytes first. */ 656 memset(val + size - EXT4_XATTR_PAD, 0, 657 EXT4_XATTR_PAD); 658 memcpy(val, i->value, i->value_len); 659 } 660 return 0; 661 } 662 663 /* Remove the old value. */ 664 memmove(first_val + size, first_val, val - first_val); 665 memset(first_val, 0, size); 666 s->here->e_value_size = 0; 667 s->here->e_value_offs = 0; 668 min_offs += size; 669 670 /* Adjust all value offsets. */ 671 last = s->first; 672 while (!IS_LAST_ENTRY(last)) { 673 size_t o = le16_to_cpu(last->e_value_offs); 674 if (!last->e_value_block && 675 last->e_value_size && o < offs) 676 last->e_value_offs = 677 cpu_to_le16(o + size); 678 last = EXT4_XATTR_NEXT(last); 679 } 680 } 681 if (!i->value) { 682 /* Remove the old name. */ 683 size_t size = EXT4_XATTR_LEN(name_len); 684 last = ENTRY((void *)last - size); 685 memmove(s->here, (void *)s->here + size, 686 (void *)last - (void *)s->here + sizeof(__u32)); 687 memset(last, 0, size); 688 } 689 } 690 691 if (i->value) { 692 /* Insert the new value. */ 693 s->here->e_value_size = cpu_to_le32(i->value_len); 694 if (i->value_len) { 695 size_t size = EXT4_XATTR_SIZE(i->value_len); 696 void *val = s->base + min_offs - size; 697 s->here->e_value_offs = cpu_to_le16(min_offs - size); 698 if (i->value == EXT4_ZERO_XATTR_VALUE) { 699 memset(val, 0, size); 700 } else { 701 /* Clear the pad bytes first. */ 702 memset(val + size - EXT4_XATTR_PAD, 0, 703 EXT4_XATTR_PAD); 704 memcpy(val, i->value, i->value_len); 705 } 706 } 707 } 708 return 0; 709 } 710 711 struct ext4_xattr_block_find { 712 struct ext4_xattr_search s; 713 struct buffer_head *bh; 714 }; 715 716 static int 717 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i, 718 struct ext4_xattr_block_find *bs) 719 { 720 struct super_block *sb = inode->i_sb; 721 int error; 722 723 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", 724 i->name_index, i->name, i->value, (long)i->value_len); 725 726 if (EXT4_I(inode)->i_file_acl) { 727 /* The inode already has an extended attribute block. */ 728 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl); 729 error = -EIO; 730 if (!bs->bh) 731 goto cleanup; 732 ea_bdebug(bs->bh, "b_count=%d, refcount=%d", 733 atomic_read(&(bs->bh->b_count)), 734 le32_to_cpu(BHDR(bs->bh)->h_refcount)); 735 if (ext4_xattr_check_block(inode, bs->bh)) { 736 EXT4_ERROR_INODE(inode, "bad block %llu", 737 EXT4_I(inode)->i_file_acl); 738 error = -EIO; 739 goto cleanup; 740 } 741 /* Find the named attribute. */ 742 bs->s.base = BHDR(bs->bh); 743 bs->s.first = BFIRST(bs->bh); 744 bs->s.end = bs->bh->b_data + bs->bh->b_size; 745 bs->s.here = bs->s.first; 746 error = ext4_xattr_find_entry(&bs->s.here, i->name_index, 747 i->name, bs->bh->b_size, 1); 748 if (error && error != -ENODATA) 749 goto cleanup; 750 bs->s.not_found = error; 751 } 752 error = 0; 753 754 cleanup: 755 return error; 756 } 757 758 static int 759 ext4_xattr_block_set(handle_t *handle, struct inode *inode, 760 struct ext4_xattr_info *i, 761 struct ext4_xattr_block_find *bs) 762 { 763 struct super_block *sb = inode->i_sb; 764 struct buffer_head *new_bh = NULL; 765 struct ext4_xattr_search *s = &bs->s; 766 struct mb_cache_entry *ce = NULL; 767 int error = 0; 768 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 769 770 #define header(x) ((struct ext4_xattr_header *)(x)) 771 772 if (i->value && i->value_len > sb->s_blocksize) 773 return -ENOSPC; 774 if (s->base) { 775 ce = mb_cache_entry_get(ext4_mb_cache, bs->bh->b_bdev, 776 bs->bh->b_blocknr); 777 error = ext4_journal_get_write_access(handle, bs->bh); 778 if (error) 779 goto cleanup; 780 lock_buffer(bs->bh); 781 782 if (header(s->base)->h_refcount == cpu_to_le32(1)) { 783 if (ce) { 784 mb_cache_entry_free(ce); 785 ce = NULL; 786 } 787 ea_bdebug(bs->bh, "modifying in-place"); 788 error = ext4_xattr_set_entry(i, s); 789 if (!error) { 790 if (!IS_LAST_ENTRY(s->first)) 791 ext4_xattr_rehash(header(s->base), 792 s->here); 793 ext4_xattr_cache_insert(ext4_mb_cache, 794 bs->bh); 795 } 796 unlock_buffer(bs->bh); 797 if (error == -EIO) 798 goto bad_block; 799 if (!error) 800 error = ext4_handle_dirty_xattr_block(handle, 801 inode, 802 bs->bh); 803 if (error) 804 goto cleanup; 805 goto inserted; 806 } else { 807 int offset = (char *)s->here - bs->bh->b_data; 808 809 unlock_buffer(bs->bh); 810 if (ce) { 811 mb_cache_entry_release(ce); 812 ce = NULL; 813 } 814 ea_bdebug(bs->bh, "cloning"); 815 s->base = kmalloc(bs->bh->b_size, GFP_NOFS); 816 error = -ENOMEM; 817 if (s->base == NULL) 818 goto cleanup; 819 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size); 820 s->first = ENTRY(header(s->base)+1); 821 header(s->base)->h_refcount = cpu_to_le32(1); 822 s->here = ENTRY(s->base + offset); 823 s->end = s->base + bs->bh->b_size; 824 } 825 } else { 826 /* Allocate a buffer where we construct the new block. */ 827 s->base = kzalloc(sb->s_blocksize, GFP_NOFS); 828 /* assert(header == s->base) */ 829 error = -ENOMEM; 830 if (s->base == NULL) 831 goto cleanup; 832 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 833 header(s->base)->h_blocks = cpu_to_le32(1); 834 header(s->base)->h_refcount = cpu_to_le32(1); 835 s->first = ENTRY(header(s->base)+1); 836 s->here = ENTRY(header(s->base)+1); 837 s->end = s->base + sb->s_blocksize; 838 } 839 840 error = ext4_xattr_set_entry(i, s); 841 if (error == -EIO) 842 goto bad_block; 843 if (error) 844 goto cleanup; 845 if (!IS_LAST_ENTRY(s->first)) 846 ext4_xattr_rehash(header(s->base), s->here); 847 848 inserted: 849 if (!IS_LAST_ENTRY(s->first)) { 850 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce); 851 if (new_bh) { 852 /* We found an identical block in the cache. */ 853 if (new_bh == bs->bh) 854 ea_bdebug(new_bh, "keeping"); 855 else { 856 /* The old block is released after updating 857 the inode. */ 858 error = dquot_alloc_block(inode, 859 EXT4_C2B(EXT4_SB(sb), 1)); 860 if (error) 861 goto cleanup; 862 error = ext4_journal_get_write_access(handle, 863 new_bh); 864 if (error) 865 goto cleanup_dquot; 866 lock_buffer(new_bh); 867 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1); 868 ea_bdebug(new_bh, "reusing; refcount now=%d", 869 le32_to_cpu(BHDR(new_bh)->h_refcount)); 870 unlock_buffer(new_bh); 871 error = ext4_handle_dirty_xattr_block(handle, 872 inode, 873 new_bh); 874 if (error) 875 goto cleanup_dquot; 876 } 877 mb_cache_entry_release(ce); 878 ce = NULL; 879 } else if (bs->bh && s->base == bs->bh->b_data) { 880 /* We were modifying this block in-place. */ 881 ea_bdebug(bs->bh, "keeping this block"); 882 new_bh = bs->bh; 883 get_bh(new_bh); 884 } else { 885 /* We need to allocate a new block */ 886 ext4_fsblk_t goal, block; 887 888 goal = ext4_group_first_block_no(sb, 889 EXT4_I(inode)->i_block_group); 890 891 /* non-extent files can't have physical blocks past 2^32 */ 892 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 893 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS; 894 895 /* 896 * take i_data_sem because we will test 897 * i_delalloc_reserved_flag in ext4_mb_new_blocks 898 */ 899 down_read((&EXT4_I(inode)->i_data_sem)); 900 block = ext4_new_meta_blocks(handle, inode, goal, 0, 901 NULL, &error); 902 up_read((&EXT4_I(inode)->i_data_sem)); 903 if (error) 904 goto cleanup; 905 906 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 907 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS); 908 909 ea_idebug(inode, "creating block %llu", 910 (unsigned long long)block); 911 912 new_bh = sb_getblk(sb, block); 913 if (unlikely(!new_bh)) { 914 error = -ENOMEM; 915 getblk_failed: 916 ext4_free_blocks(handle, inode, NULL, block, 1, 917 EXT4_FREE_BLOCKS_METADATA); 918 goto cleanup; 919 } 920 lock_buffer(new_bh); 921 error = ext4_journal_get_create_access(handle, new_bh); 922 if (error) { 923 unlock_buffer(new_bh); 924 error = -EIO; 925 goto getblk_failed; 926 } 927 memcpy(new_bh->b_data, s->base, new_bh->b_size); 928 set_buffer_uptodate(new_bh); 929 unlock_buffer(new_bh); 930 ext4_xattr_cache_insert(ext4_mb_cache, new_bh); 931 error = ext4_handle_dirty_xattr_block(handle, 932 inode, new_bh); 933 if (error) 934 goto cleanup; 935 } 936 } 937 938 /* Update the inode. */ 939 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; 940 941 /* Drop the previous xattr block. */ 942 if (bs->bh && bs->bh != new_bh) 943 ext4_xattr_release_block(handle, inode, bs->bh); 944 error = 0; 945 946 cleanup: 947 if (ce) 948 mb_cache_entry_release(ce); 949 brelse(new_bh); 950 if (!(bs->bh && s->base == bs->bh->b_data)) 951 kfree(s->base); 952 953 return error; 954 955 cleanup_dquot: 956 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1)); 957 goto cleanup; 958 959 bad_block: 960 EXT4_ERROR_INODE(inode, "bad block %llu", 961 EXT4_I(inode)->i_file_acl); 962 goto cleanup; 963 964 #undef header 965 } 966 967 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, 968 struct ext4_xattr_ibody_find *is) 969 { 970 struct ext4_xattr_ibody_header *header; 971 struct ext4_inode *raw_inode; 972 int error; 973 974 if (EXT4_I(inode)->i_extra_isize == 0) 975 return 0; 976 raw_inode = ext4_raw_inode(&is->iloc); 977 header = IHDR(inode, raw_inode); 978 is->s.base = is->s.first = IFIRST(header); 979 is->s.here = is->s.first; 980 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 981 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { 982 error = ext4_xattr_check_names(IFIRST(header), is->s.end); 983 if (error) 984 return error; 985 /* Find the named attribute. */ 986 error = ext4_xattr_find_entry(&is->s.here, i->name_index, 987 i->name, is->s.end - 988 (void *)is->s.base, 0); 989 if (error && error != -ENODATA) 990 return error; 991 is->s.not_found = error; 992 } 993 return 0; 994 } 995 996 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode, 997 struct ext4_xattr_info *i, 998 struct ext4_xattr_ibody_find *is) 999 { 1000 struct ext4_xattr_ibody_header *header; 1001 struct ext4_xattr_search *s = &is->s; 1002 int error; 1003 1004 if (EXT4_I(inode)->i_extra_isize == 0) 1005 return -ENOSPC; 1006 error = ext4_xattr_set_entry(i, s); 1007 if (error) { 1008 if (error == -ENOSPC && 1009 ext4_has_inline_data(inode)) { 1010 error = ext4_try_to_evict_inline_data(handle, inode, 1011 EXT4_XATTR_LEN(strlen(i->name) + 1012 EXT4_XATTR_SIZE(i->value_len))); 1013 if (error) 1014 return error; 1015 error = ext4_xattr_ibody_find(inode, i, is); 1016 if (error) 1017 return error; 1018 error = ext4_xattr_set_entry(i, s); 1019 } 1020 if (error) 1021 return error; 1022 } 1023 header = IHDR(inode, ext4_raw_inode(&is->iloc)); 1024 if (!IS_LAST_ENTRY(s->first)) { 1025 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 1026 ext4_set_inode_state(inode, EXT4_STATE_XATTR); 1027 } else { 1028 header->h_magic = cpu_to_le32(0); 1029 ext4_clear_inode_state(inode, EXT4_STATE_XATTR); 1030 } 1031 return 0; 1032 } 1033 1034 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode, 1035 struct ext4_xattr_info *i, 1036 struct ext4_xattr_ibody_find *is) 1037 { 1038 struct ext4_xattr_ibody_header *header; 1039 struct ext4_xattr_search *s = &is->s; 1040 int error; 1041 1042 if (EXT4_I(inode)->i_extra_isize == 0) 1043 return -ENOSPC; 1044 error = ext4_xattr_set_entry(i, s); 1045 if (error) 1046 return error; 1047 header = IHDR(inode, ext4_raw_inode(&is->iloc)); 1048 if (!IS_LAST_ENTRY(s->first)) { 1049 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 1050 ext4_set_inode_state(inode, EXT4_STATE_XATTR); 1051 } else { 1052 header->h_magic = cpu_to_le32(0); 1053 ext4_clear_inode_state(inode, EXT4_STATE_XATTR); 1054 } 1055 return 0; 1056 } 1057 1058 /* 1059 * ext4_xattr_set_handle() 1060 * 1061 * Create, replace or remove an extended attribute for this inode. Value 1062 * is NULL to remove an existing extended attribute, and non-NULL to 1063 * either replace an existing extended attribute, or create a new extended 1064 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 1065 * specify that an extended attribute must exist and must not exist 1066 * previous to the call, respectively. 1067 * 1068 * Returns 0, or a negative error number on failure. 1069 */ 1070 int 1071 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, 1072 const char *name, const void *value, size_t value_len, 1073 int flags) 1074 { 1075 struct ext4_xattr_info i = { 1076 .name_index = name_index, 1077 .name = name, 1078 .value = value, 1079 .value_len = value_len, 1080 1081 }; 1082 struct ext4_xattr_ibody_find is = { 1083 .s = { .not_found = -ENODATA, }, 1084 }; 1085 struct ext4_xattr_block_find bs = { 1086 .s = { .not_found = -ENODATA, }, 1087 }; 1088 unsigned long no_expand; 1089 int error; 1090 1091 if (!name) 1092 return -EINVAL; 1093 if (strlen(name) > 255) 1094 return -ERANGE; 1095 down_write(&EXT4_I(inode)->xattr_sem); 1096 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND); 1097 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); 1098 1099 error = ext4_reserve_inode_write(handle, inode, &is.iloc); 1100 if (error) 1101 goto cleanup; 1102 1103 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) { 1104 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc); 1105 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); 1106 ext4_clear_inode_state(inode, EXT4_STATE_NEW); 1107 } 1108 1109 error = ext4_xattr_ibody_find(inode, &i, &is); 1110 if (error) 1111 goto cleanup; 1112 if (is.s.not_found) 1113 error = ext4_xattr_block_find(inode, &i, &bs); 1114 if (error) 1115 goto cleanup; 1116 if (is.s.not_found && bs.s.not_found) { 1117 error = -ENODATA; 1118 if (flags & XATTR_REPLACE) 1119 goto cleanup; 1120 error = 0; 1121 if (!value) 1122 goto cleanup; 1123 } else { 1124 error = -EEXIST; 1125 if (flags & XATTR_CREATE) 1126 goto cleanup; 1127 } 1128 if (!value) { 1129 if (!is.s.not_found) 1130 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1131 else if (!bs.s.not_found) 1132 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1133 } else { 1134 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1135 if (!error && !bs.s.not_found) { 1136 i.value = NULL; 1137 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1138 } else if (error == -ENOSPC) { 1139 if (EXT4_I(inode)->i_file_acl && !bs.s.base) { 1140 error = ext4_xattr_block_find(inode, &i, &bs); 1141 if (error) 1142 goto cleanup; 1143 } 1144 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1145 if (error) 1146 goto cleanup; 1147 if (!is.s.not_found) { 1148 i.value = NULL; 1149 error = ext4_xattr_ibody_set(handle, inode, &i, 1150 &is); 1151 } 1152 } 1153 } 1154 if (!error) { 1155 ext4_xattr_update_super_block(handle, inode->i_sb); 1156 inode->i_ctime = ext4_current_time(inode); 1157 if (!value) 1158 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); 1159 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc); 1160 /* 1161 * The bh is consumed by ext4_mark_iloc_dirty, even with 1162 * error != 0. 1163 */ 1164 is.iloc.bh = NULL; 1165 if (IS_SYNC(inode)) 1166 ext4_handle_sync(handle); 1167 } 1168 1169 cleanup: 1170 brelse(is.iloc.bh); 1171 brelse(bs.bh); 1172 if (no_expand == 0) 1173 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); 1174 up_write(&EXT4_I(inode)->xattr_sem); 1175 return error; 1176 } 1177 1178 /* 1179 * ext4_xattr_set() 1180 * 1181 * Like ext4_xattr_set_handle, but start from an inode. This extended 1182 * attribute modification is a filesystem transaction by itself. 1183 * 1184 * Returns 0, or a negative error number on failure. 1185 */ 1186 int 1187 ext4_xattr_set(struct inode *inode, int name_index, const char *name, 1188 const void *value, size_t value_len, int flags) 1189 { 1190 handle_t *handle; 1191 int error, retries = 0; 1192 int credits = ext4_jbd2_credits_xattr(inode); 1193 1194 retry: 1195 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits); 1196 if (IS_ERR(handle)) { 1197 error = PTR_ERR(handle); 1198 } else { 1199 int error2; 1200 1201 error = ext4_xattr_set_handle(handle, inode, name_index, name, 1202 value, value_len, flags); 1203 error2 = ext4_journal_stop(handle); 1204 if (error == -ENOSPC && 1205 ext4_should_retry_alloc(inode->i_sb, &retries)) 1206 goto retry; 1207 if (error == 0) 1208 error = error2; 1209 } 1210 1211 return error; 1212 } 1213 1214 /* 1215 * Shift the EA entries in the inode to create space for the increased 1216 * i_extra_isize. 1217 */ 1218 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry, 1219 int value_offs_shift, void *to, 1220 void *from, size_t n, int blocksize) 1221 { 1222 struct ext4_xattr_entry *last = entry; 1223 int new_offs; 1224 1225 /* Adjust the value offsets of the entries */ 1226 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1227 if (!last->e_value_block && last->e_value_size) { 1228 new_offs = le16_to_cpu(last->e_value_offs) + 1229 value_offs_shift; 1230 BUG_ON(new_offs + le32_to_cpu(last->e_value_size) 1231 > blocksize); 1232 last->e_value_offs = cpu_to_le16(new_offs); 1233 } 1234 } 1235 /* Shift the entries by n bytes */ 1236 memmove(to, from, n); 1237 } 1238 1239 /* 1240 * Expand an inode by new_extra_isize bytes when EAs are present. 1241 * Returns 0 on success or negative error number on failure. 1242 */ 1243 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, 1244 struct ext4_inode *raw_inode, handle_t *handle) 1245 { 1246 struct ext4_xattr_ibody_header *header; 1247 struct ext4_xattr_entry *entry, *last, *first; 1248 struct buffer_head *bh = NULL; 1249 struct ext4_xattr_ibody_find *is = NULL; 1250 struct ext4_xattr_block_find *bs = NULL; 1251 char *buffer = NULL, *b_entry_name = NULL; 1252 size_t min_offs, free; 1253 int total_ino; 1254 void *base, *start, *end; 1255 int extra_isize = 0, error = 0, tried_min_extra_isize = 0; 1256 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize); 1257 1258 down_write(&EXT4_I(inode)->xattr_sem); 1259 retry: 1260 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) { 1261 up_write(&EXT4_I(inode)->xattr_sem); 1262 return 0; 1263 } 1264 1265 header = IHDR(inode, raw_inode); 1266 entry = IFIRST(header); 1267 1268 /* 1269 * Check if enough free space is available in the inode to shift the 1270 * entries ahead by new_extra_isize. 1271 */ 1272 1273 base = start = entry; 1274 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 1275 min_offs = end - base; 1276 last = entry; 1277 total_ino = sizeof(struct ext4_xattr_ibody_header); 1278 1279 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino); 1280 if (free >= new_extra_isize) { 1281 entry = IFIRST(header); 1282 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize 1283 - new_extra_isize, (void *)raw_inode + 1284 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize, 1285 (void *)header, total_ino, 1286 inode->i_sb->s_blocksize); 1287 EXT4_I(inode)->i_extra_isize = new_extra_isize; 1288 error = 0; 1289 goto cleanup; 1290 } 1291 1292 /* 1293 * Enough free space isn't available in the inode, check if 1294 * EA block can hold new_extra_isize bytes. 1295 */ 1296 if (EXT4_I(inode)->i_file_acl) { 1297 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1298 error = -EIO; 1299 if (!bh) 1300 goto cleanup; 1301 if (ext4_xattr_check_block(inode, bh)) { 1302 EXT4_ERROR_INODE(inode, "bad block %llu", 1303 EXT4_I(inode)->i_file_acl); 1304 error = -EIO; 1305 goto cleanup; 1306 } 1307 base = BHDR(bh); 1308 first = BFIRST(bh); 1309 end = bh->b_data + bh->b_size; 1310 min_offs = end - base; 1311 free = ext4_xattr_free_space(first, &min_offs, base, NULL); 1312 if (free < new_extra_isize) { 1313 if (!tried_min_extra_isize && s_min_extra_isize) { 1314 tried_min_extra_isize++; 1315 new_extra_isize = s_min_extra_isize; 1316 brelse(bh); 1317 goto retry; 1318 } 1319 error = -1; 1320 goto cleanup; 1321 } 1322 } else { 1323 free = inode->i_sb->s_blocksize; 1324 } 1325 1326 while (new_extra_isize > 0) { 1327 size_t offs, size, entry_size; 1328 struct ext4_xattr_entry *small_entry = NULL; 1329 struct ext4_xattr_info i = { 1330 .value = NULL, 1331 .value_len = 0, 1332 }; 1333 unsigned int total_size; /* EA entry size + value size */ 1334 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */ 1335 unsigned int min_total_size = ~0U; 1336 1337 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS); 1338 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS); 1339 if (!is || !bs) { 1340 error = -ENOMEM; 1341 goto cleanup; 1342 } 1343 1344 is->s.not_found = -ENODATA; 1345 bs->s.not_found = -ENODATA; 1346 is->iloc.bh = NULL; 1347 bs->bh = NULL; 1348 1349 last = IFIRST(header); 1350 /* Find the entry best suited to be pushed into EA block */ 1351 entry = NULL; 1352 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1353 total_size = 1354 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) + 1355 EXT4_XATTR_LEN(last->e_name_len); 1356 if (total_size <= free && total_size < min_total_size) { 1357 if (total_size < new_extra_isize) { 1358 small_entry = last; 1359 } else { 1360 entry = last; 1361 min_total_size = total_size; 1362 } 1363 } 1364 } 1365 1366 if (entry == NULL) { 1367 if (small_entry) { 1368 entry = small_entry; 1369 } else { 1370 if (!tried_min_extra_isize && 1371 s_min_extra_isize) { 1372 tried_min_extra_isize++; 1373 new_extra_isize = s_min_extra_isize; 1374 kfree(is); is = NULL; 1375 kfree(bs); bs = NULL; 1376 brelse(bh); 1377 goto retry; 1378 } 1379 error = -1; 1380 goto cleanup; 1381 } 1382 } 1383 offs = le16_to_cpu(entry->e_value_offs); 1384 size = le32_to_cpu(entry->e_value_size); 1385 entry_size = EXT4_XATTR_LEN(entry->e_name_len); 1386 i.name_index = entry->e_name_index, 1387 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS); 1388 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS); 1389 if (!buffer || !b_entry_name) { 1390 error = -ENOMEM; 1391 goto cleanup; 1392 } 1393 /* Save the entry name and the entry value */ 1394 memcpy(buffer, (void *)IFIRST(header) + offs, 1395 EXT4_XATTR_SIZE(size)); 1396 memcpy(b_entry_name, entry->e_name, entry->e_name_len); 1397 b_entry_name[entry->e_name_len] = '\0'; 1398 i.name = b_entry_name; 1399 1400 error = ext4_get_inode_loc(inode, &is->iloc); 1401 if (error) 1402 goto cleanup; 1403 1404 error = ext4_xattr_ibody_find(inode, &i, is); 1405 if (error) 1406 goto cleanup; 1407 1408 /* Remove the chosen entry from the inode */ 1409 error = ext4_xattr_ibody_set(handle, inode, &i, is); 1410 if (error) 1411 goto cleanup; 1412 1413 entry = IFIRST(header); 1414 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize) 1415 shift_bytes = new_extra_isize; 1416 else 1417 shift_bytes = entry_size + size; 1418 /* Adjust the offsets and shift the remaining entries ahead */ 1419 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize - 1420 shift_bytes, (void *)raw_inode + 1421 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes, 1422 (void *)header, total_ino - entry_size, 1423 inode->i_sb->s_blocksize); 1424 1425 extra_isize += shift_bytes; 1426 new_extra_isize -= shift_bytes; 1427 EXT4_I(inode)->i_extra_isize = extra_isize; 1428 1429 i.name = b_entry_name; 1430 i.value = buffer; 1431 i.value_len = size; 1432 error = ext4_xattr_block_find(inode, &i, bs); 1433 if (error) 1434 goto cleanup; 1435 1436 /* Add entry which was removed from the inode into the block */ 1437 error = ext4_xattr_block_set(handle, inode, &i, bs); 1438 if (error) 1439 goto cleanup; 1440 kfree(b_entry_name); 1441 kfree(buffer); 1442 b_entry_name = NULL; 1443 buffer = NULL; 1444 brelse(is->iloc.bh); 1445 kfree(is); 1446 kfree(bs); 1447 } 1448 brelse(bh); 1449 up_write(&EXT4_I(inode)->xattr_sem); 1450 return 0; 1451 1452 cleanup: 1453 kfree(b_entry_name); 1454 kfree(buffer); 1455 if (is) 1456 brelse(is->iloc.bh); 1457 kfree(is); 1458 kfree(bs); 1459 brelse(bh); 1460 up_write(&EXT4_I(inode)->xattr_sem); 1461 return error; 1462 } 1463 1464 1465 1466 /* 1467 * ext4_xattr_delete_inode() 1468 * 1469 * Free extended attribute resources associated with this inode. This 1470 * is called immediately before an inode is freed. We have exclusive 1471 * access to the inode. 1472 */ 1473 void 1474 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode) 1475 { 1476 struct buffer_head *bh = NULL; 1477 1478 if (!EXT4_I(inode)->i_file_acl) 1479 goto cleanup; 1480 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1481 if (!bh) { 1482 EXT4_ERROR_INODE(inode, "block %llu read error", 1483 EXT4_I(inode)->i_file_acl); 1484 goto cleanup; 1485 } 1486 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 1487 BHDR(bh)->h_blocks != cpu_to_le32(1)) { 1488 EXT4_ERROR_INODE(inode, "bad block %llu", 1489 EXT4_I(inode)->i_file_acl); 1490 goto cleanup; 1491 } 1492 ext4_xattr_release_block(handle, inode, bh); 1493 EXT4_I(inode)->i_file_acl = 0; 1494 1495 cleanup: 1496 brelse(bh); 1497 } 1498 1499 /* 1500 * ext4_xattr_put_super() 1501 * 1502 * This is called when a file system is unmounted. 1503 */ 1504 void 1505 ext4_xattr_put_super(struct super_block *sb) 1506 { 1507 mb_cache_shrink(sb->s_bdev); 1508 } 1509 1510 /* 1511 * ext4_xattr_cache_insert() 1512 * 1513 * Create a new entry in the extended attribute cache, and insert 1514 * it unless such an entry is already in the cache. 1515 * 1516 * Returns 0, or a negative error number on failure. 1517 */ 1518 static void 1519 ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh) 1520 { 1521 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash); 1522 struct mb_cache_entry *ce; 1523 int error; 1524 1525 ce = mb_cache_entry_alloc(ext4_mb_cache, GFP_NOFS); 1526 if (!ce) { 1527 ea_bdebug(bh, "out of memory"); 1528 return; 1529 } 1530 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash); 1531 if (error) { 1532 mb_cache_entry_free(ce); 1533 if (error == -EBUSY) { 1534 ea_bdebug(bh, "already in cache"); 1535 error = 0; 1536 } 1537 } else { 1538 ea_bdebug(bh, "inserting [%x]", (int)hash); 1539 mb_cache_entry_release(ce); 1540 } 1541 } 1542 1543 /* 1544 * ext4_xattr_cmp() 1545 * 1546 * Compare two extended attribute blocks for equality. 1547 * 1548 * Returns 0 if the blocks are equal, 1 if they differ, and 1549 * a negative error number on errors. 1550 */ 1551 static int 1552 ext4_xattr_cmp(struct ext4_xattr_header *header1, 1553 struct ext4_xattr_header *header2) 1554 { 1555 struct ext4_xattr_entry *entry1, *entry2; 1556 1557 entry1 = ENTRY(header1+1); 1558 entry2 = ENTRY(header2+1); 1559 while (!IS_LAST_ENTRY(entry1)) { 1560 if (IS_LAST_ENTRY(entry2)) 1561 return 1; 1562 if (entry1->e_hash != entry2->e_hash || 1563 entry1->e_name_index != entry2->e_name_index || 1564 entry1->e_name_len != entry2->e_name_len || 1565 entry1->e_value_size != entry2->e_value_size || 1566 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) 1567 return 1; 1568 if (entry1->e_value_block != 0 || entry2->e_value_block != 0) 1569 return -EIO; 1570 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), 1571 (char *)header2 + le16_to_cpu(entry2->e_value_offs), 1572 le32_to_cpu(entry1->e_value_size))) 1573 return 1; 1574 1575 entry1 = EXT4_XATTR_NEXT(entry1); 1576 entry2 = EXT4_XATTR_NEXT(entry2); 1577 } 1578 if (!IS_LAST_ENTRY(entry2)) 1579 return 1; 1580 return 0; 1581 } 1582 1583 /* 1584 * ext4_xattr_cache_find() 1585 * 1586 * Find an identical extended attribute block. 1587 * 1588 * Returns a pointer to the block found, or NULL if such a block was 1589 * not found or an error occurred. 1590 */ 1591 static struct buffer_head * 1592 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header, 1593 struct mb_cache_entry **pce) 1594 { 1595 __u32 hash = le32_to_cpu(header->h_hash); 1596 struct mb_cache_entry *ce; 1597 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 1598 1599 if (!header->h_hash) 1600 return NULL; /* never share */ 1601 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); 1602 again: 1603 ce = mb_cache_entry_find_first(ext4_mb_cache, inode->i_sb->s_bdev, 1604 hash); 1605 while (ce) { 1606 struct buffer_head *bh; 1607 1608 if (IS_ERR(ce)) { 1609 if (PTR_ERR(ce) == -EAGAIN) 1610 goto again; 1611 break; 1612 } 1613 bh = sb_bread(inode->i_sb, ce->e_block); 1614 if (!bh) { 1615 EXT4_ERROR_INODE(inode, "block %lu read error", 1616 (unsigned long) ce->e_block); 1617 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >= 1618 EXT4_XATTR_REFCOUNT_MAX) { 1619 ea_idebug(inode, "block %lu refcount %d>=%d", 1620 (unsigned long) ce->e_block, 1621 le32_to_cpu(BHDR(bh)->h_refcount), 1622 EXT4_XATTR_REFCOUNT_MAX); 1623 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) { 1624 *pce = ce; 1625 return bh; 1626 } 1627 brelse(bh); 1628 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash); 1629 } 1630 return NULL; 1631 } 1632 1633 #define NAME_HASH_SHIFT 5 1634 #define VALUE_HASH_SHIFT 16 1635 1636 /* 1637 * ext4_xattr_hash_entry() 1638 * 1639 * Compute the hash of an extended attribute. 1640 */ 1641 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header, 1642 struct ext4_xattr_entry *entry) 1643 { 1644 __u32 hash = 0; 1645 char *name = entry->e_name; 1646 int n; 1647 1648 for (n = 0; n < entry->e_name_len; n++) { 1649 hash = (hash << NAME_HASH_SHIFT) ^ 1650 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ 1651 *name++; 1652 } 1653 1654 if (entry->e_value_block == 0 && entry->e_value_size != 0) { 1655 __le32 *value = (__le32 *)((char *)header + 1656 le16_to_cpu(entry->e_value_offs)); 1657 for (n = (le32_to_cpu(entry->e_value_size) + 1658 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) { 1659 hash = (hash << VALUE_HASH_SHIFT) ^ 1660 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ 1661 le32_to_cpu(*value++); 1662 } 1663 } 1664 entry->e_hash = cpu_to_le32(hash); 1665 } 1666 1667 #undef NAME_HASH_SHIFT 1668 #undef VALUE_HASH_SHIFT 1669 1670 #define BLOCK_HASH_SHIFT 16 1671 1672 /* 1673 * ext4_xattr_rehash() 1674 * 1675 * Re-compute the extended attribute hash value after an entry has changed. 1676 */ 1677 static void ext4_xattr_rehash(struct ext4_xattr_header *header, 1678 struct ext4_xattr_entry *entry) 1679 { 1680 struct ext4_xattr_entry *here; 1681 __u32 hash = 0; 1682 1683 ext4_xattr_hash_entry(header, entry); 1684 here = ENTRY(header+1); 1685 while (!IS_LAST_ENTRY(here)) { 1686 if (!here->e_hash) { 1687 /* Block is not shared if an entry's hash value == 0 */ 1688 hash = 0; 1689 break; 1690 } 1691 hash = (hash << BLOCK_HASH_SHIFT) ^ 1692 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ 1693 le32_to_cpu(here->e_hash); 1694 here = EXT4_XATTR_NEXT(here); 1695 } 1696 header->h_hash = cpu_to_le32(hash); 1697 } 1698 1699 #undef BLOCK_HASH_SHIFT 1700 1701 #define HASH_BUCKET_BITS 10 1702 1703 struct mb_cache * 1704 ext4_xattr_create_cache(char *name) 1705 { 1706 return mb_cache_create(name, HASH_BUCKET_BITS); 1707 } 1708 1709 void ext4_xattr_destroy_cache(struct mb_cache *cache) 1710 { 1711 if (cache) 1712 mb_cache_destroy(cache); 1713 } 1714 1715