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 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 struct mb_cache *ext4_xattr_cache; 94 95 static const struct xattr_handler *ext4_xattr_handler_map[] = { 96 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler, 97 #ifdef CONFIG_EXT4_FS_POSIX_ACL 98 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler, 99 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler, 100 #endif 101 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler, 102 #ifdef CONFIG_EXT4_FS_SECURITY 103 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler, 104 #endif 105 }; 106 107 const struct xattr_handler *ext4_xattr_handlers[] = { 108 &ext4_xattr_user_handler, 109 &ext4_xattr_trusted_handler, 110 #ifdef CONFIG_EXT4_FS_POSIX_ACL 111 &ext4_xattr_acl_access_handler, 112 &ext4_xattr_acl_default_handler, 113 #endif 114 #ifdef CONFIG_EXT4_FS_SECURITY 115 &ext4_xattr_security_handler, 116 #endif 117 NULL 118 }; 119 120 static __le32 ext4_xattr_block_csum(struct inode *inode, 121 sector_t block_nr, 122 struct ext4_xattr_header *hdr) 123 { 124 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 125 __u32 csum; 126 __le32 save_csum; 127 __le64 dsk_block_nr = cpu_to_le64(block_nr); 128 129 save_csum = hdr->h_checksum; 130 hdr->h_checksum = 0; 131 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr, 132 sizeof(dsk_block_nr)); 133 csum = ext4_chksum(sbi, csum, (__u8 *)hdr, 134 EXT4_BLOCK_SIZE(inode->i_sb)); 135 136 hdr->h_checksum = save_csum; 137 return cpu_to_le32(csum); 138 } 139 140 static int ext4_xattr_block_csum_verify(struct inode *inode, 141 sector_t block_nr, 142 struct ext4_xattr_header *hdr) 143 { 144 if (EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, 145 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM) && 146 (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr))) 147 return 0; 148 return 1; 149 } 150 151 static void ext4_xattr_block_csum_set(struct inode *inode, 152 sector_t block_nr, 153 struct ext4_xattr_header *hdr) 154 { 155 if (!EXT4_HAS_RO_COMPAT_FEATURE(inode->i_sb, 156 EXT4_FEATURE_RO_COMPAT_METADATA_CSUM)) 157 return; 158 159 hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr); 160 } 161 162 static inline int ext4_handle_dirty_xattr_block(handle_t *handle, 163 struct inode *inode, 164 struct buffer_head *bh) 165 { 166 ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh)); 167 return ext4_handle_dirty_metadata(handle, inode, bh); 168 } 169 170 static inline const struct xattr_handler * 171 ext4_xattr_handler(int name_index) 172 { 173 const struct xattr_handler *handler = NULL; 174 175 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map)) 176 handler = ext4_xattr_handler_map[name_index]; 177 return handler; 178 } 179 180 /* 181 * Inode operation listxattr() 182 * 183 * dentry->d_inode->i_mutex: don't care 184 */ 185 ssize_t 186 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size) 187 { 188 return ext4_xattr_list(dentry, buffer, size); 189 } 190 191 static int 192 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end) 193 { 194 while (!IS_LAST_ENTRY(entry)) { 195 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry); 196 if ((void *)next >= end) 197 return -EIO; 198 entry = next; 199 } 200 return 0; 201 } 202 203 static inline int 204 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh) 205 { 206 int error; 207 208 if (buffer_verified(bh)) 209 return 0; 210 211 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 212 BHDR(bh)->h_blocks != cpu_to_le32(1)) 213 return -EIO; 214 if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh))) 215 return -EIO; 216 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size); 217 if (!error) 218 set_buffer_verified(bh); 219 return error; 220 } 221 222 static inline int 223 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size) 224 { 225 size_t value_size = le32_to_cpu(entry->e_value_size); 226 227 if (entry->e_value_block != 0 || value_size > size || 228 le16_to_cpu(entry->e_value_offs) + value_size > size) 229 return -EIO; 230 return 0; 231 } 232 233 static int 234 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index, 235 const char *name, size_t size, int sorted) 236 { 237 struct ext4_xattr_entry *entry; 238 size_t name_len; 239 int cmp = 1; 240 241 if (name == NULL) 242 return -EINVAL; 243 name_len = strlen(name); 244 entry = *pentry; 245 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 246 cmp = name_index - entry->e_name_index; 247 if (!cmp) 248 cmp = name_len - entry->e_name_len; 249 if (!cmp) 250 cmp = memcmp(name, entry->e_name, name_len); 251 if (cmp <= 0 && (sorted || cmp == 0)) 252 break; 253 } 254 *pentry = entry; 255 if (!cmp && ext4_xattr_check_entry(entry, size)) 256 return -EIO; 257 return cmp ? -ENODATA : 0; 258 } 259 260 static int 261 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name, 262 void *buffer, size_t buffer_size) 263 { 264 struct buffer_head *bh = NULL; 265 struct ext4_xattr_entry *entry; 266 size_t size; 267 int error; 268 269 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", 270 name_index, name, buffer, (long)buffer_size); 271 272 error = -ENODATA; 273 if (!EXT4_I(inode)->i_file_acl) 274 goto cleanup; 275 ea_idebug(inode, "reading block %llu", 276 (unsigned long long)EXT4_I(inode)->i_file_acl); 277 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 278 if (!bh) 279 goto cleanup; 280 ea_bdebug(bh, "b_count=%d, refcount=%d", 281 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 282 if (ext4_xattr_check_block(inode, bh)) { 283 bad_block: 284 EXT4_ERROR_INODE(inode, "bad block %llu", 285 EXT4_I(inode)->i_file_acl); 286 error = -EIO; 287 goto cleanup; 288 } 289 ext4_xattr_cache_insert(bh); 290 entry = BFIRST(bh); 291 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1); 292 if (error == -EIO) 293 goto bad_block; 294 if (error) 295 goto cleanup; 296 size = le32_to_cpu(entry->e_value_size); 297 if (buffer) { 298 error = -ERANGE; 299 if (size > buffer_size) 300 goto cleanup; 301 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), 302 size); 303 } 304 error = size; 305 306 cleanup: 307 brelse(bh); 308 return error; 309 } 310 311 int 312 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name, 313 void *buffer, size_t buffer_size) 314 { 315 struct ext4_xattr_ibody_header *header; 316 struct ext4_xattr_entry *entry; 317 struct ext4_inode *raw_inode; 318 struct ext4_iloc iloc; 319 size_t size; 320 void *end; 321 int error; 322 323 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR)) 324 return -ENODATA; 325 error = ext4_get_inode_loc(inode, &iloc); 326 if (error) 327 return error; 328 raw_inode = ext4_raw_inode(&iloc); 329 header = IHDR(inode, raw_inode); 330 entry = IFIRST(header); 331 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 332 error = ext4_xattr_check_names(entry, end); 333 if (error) 334 goto cleanup; 335 error = ext4_xattr_find_entry(&entry, name_index, name, 336 end - (void *)entry, 0); 337 if (error) 338 goto cleanup; 339 size = le32_to_cpu(entry->e_value_size); 340 if (buffer) { 341 error = -ERANGE; 342 if (size > buffer_size) 343 goto cleanup; 344 memcpy(buffer, (void *)IFIRST(header) + 345 le16_to_cpu(entry->e_value_offs), size); 346 } 347 error = size; 348 349 cleanup: 350 brelse(iloc.bh); 351 return error; 352 } 353 354 /* 355 * ext4_xattr_get() 356 * 357 * Copy an extended attribute into the buffer 358 * provided, or compute the buffer size required. 359 * Buffer is NULL to compute the size of the buffer required. 360 * 361 * Returns a negative error number on failure, or the number of bytes 362 * used / required on success. 363 */ 364 int 365 ext4_xattr_get(struct inode *inode, int name_index, const char *name, 366 void *buffer, size_t buffer_size) 367 { 368 int error; 369 370 down_read(&EXT4_I(inode)->xattr_sem); 371 error = ext4_xattr_ibody_get(inode, name_index, name, buffer, 372 buffer_size); 373 if (error == -ENODATA) 374 error = ext4_xattr_block_get(inode, name_index, name, buffer, 375 buffer_size); 376 up_read(&EXT4_I(inode)->xattr_sem); 377 return error; 378 } 379 380 static int 381 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry, 382 char *buffer, size_t buffer_size) 383 { 384 size_t rest = buffer_size; 385 386 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 387 const struct xattr_handler *handler = 388 ext4_xattr_handler(entry->e_name_index); 389 390 if (handler) { 391 size_t size = handler->list(dentry, buffer, rest, 392 entry->e_name, 393 entry->e_name_len, 394 handler->flags); 395 if (buffer) { 396 if (size > rest) 397 return -ERANGE; 398 buffer += size; 399 } 400 rest -= size; 401 } 402 } 403 return buffer_size - rest; 404 } 405 406 static int 407 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size) 408 { 409 struct inode *inode = dentry->d_inode; 410 struct buffer_head *bh = NULL; 411 int error; 412 413 ea_idebug(inode, "buffer=%p, buffer_size=%ld", 414 buffer, (long)buffer_size); 415 416 error = 0; 417 if (!EXT4_I(inode)->i_file_acl) 418 goto cleanup; 419 ea_idebug(inode, "reading block %llu", 420 (unsigned long long)EXT4_I(inode)->i_file_acl); 421 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 422 error = -EIO; 423 if (!bh) 424 goto cleanup; 425 ea_bdebug(bh, "b_count=%d, refcount=%d", 426 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 427 if (ext4_xattr_check_block(inode, bh)) { 428 EXT4_ERROR_INODE(inode, "bad block %llu", 429 EXT4_I(inode)->i_file_acl); 430 error = -EIO; 431 goto cleanup; 432 } 433 ext4_xattr_cache_insert(bh); 434 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size); 435 436 cleanup: 437 brelse(bh); 438 439 return error; 440 } 441 442 static int 443 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size) 444 { 445 struct inode *inode = dentry->d_inode; 446 struct ext4_xattr_ibody_header *header; 447 struct ext4_inode *raw_inode; 448 struct ext4_iloc iloc; 449 void *end; 450 int error; 451 452 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR)) 453 return 0; 454 error = ext4_get_inode_loc(inode, &iloc); 455 if (error) 456 return error; 457 raw_inode = ext4_raw_inode(&iloc); 458 header = IHDR(inode, raw_inode); 459 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 460 error = ext4_xattr_check_names(IFIRST(header), end); 461 if (error) 462 goto cleanup; 463 error = ext4_xattr_list_entries(dentry, IFIRST(header), 464 buffer, buffer_size); 465 466 cleanup: 467 brelse(iloc.bh); 468 return error; 469 } 470 471 /* 472 * ext4_xattr_list() 473 * 474 * Copy a list of attribute names into the buffer 475 * provided, or compute the buffer size required. 476 * Buffer is NULL to compute the size of the buffer required. 477 * 478 * Returns a negative error number on failure, or the number of bytes 479 * used / required on success. 480 */ 481 static int 482 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size) 483 { 484 int ret, ret2; 485 486 down_read(&EXT4_I(dentry->d_inode)->xattr_sem); 487 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size); 488 if (ret < 0) 489 goto errout; 490 if (buffer) { 491 buffer += ret; 492 buffer_size -= ret; 493 } 494 ret = ext4_xattr_block_list(dentry, buffer, buffer_size); 495 if (ret < 0) 496 goto errout; 497 ret += ret2; 498 errout: 499 up_read(&EXT4_I(dentry->d_inode)->xattr_sem); 500 return ret; 501 } 502 503 /* 504 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is 505 * not set, set it. 506 */ 507 static void ext4_xattr_update_super_block(handle_t *handle, 508 struct super_block *sb) 509 { 510 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR)) 511 return; 512 513 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) { 514 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR); 515 ext4_handle_dirty_super(handle, sb); 516 } 517 } 518 519 /* 520 * Release the xattr block BH: If the reference count is > 1, decrement 521 * it; otherwise free the block. 522 */ 523 static void 524 ext4_xattr_release_block(handle_t *handle, struct inode *inode, 525 struct buffer_head *bh) 526 { 527 struct mb_cache_entry *ce = NULL; 528 int error = 0; 529 530 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr); 531 error = ext4_journal_get_write_access(handle, bh); 532 if (error) 533 goto out; 534 535 lock_buffer(bh); 536 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) { 537 ea_bdebug(bh, "refcount now=0; freeing"); 538 if (ce) 539 mb_cache_entry_free(ce); 540 get_bh(bh); 541 ext4_free_blocks(handle, inode, bh, 0, 1, 542 EXT4_FREE_BLOCKS_METADATA | 543 EXT4_FREE_BLOCKS_FORGET); 544 unlock_buffer(bh); 545 } else { 546 le32_add_cpu(&BHDR(bh)->h_refcount, -1); 547 if (ce) 548 mb_cache_entry_release(ce); 549 unlock_buffer(bh); 550 error = ext4_handle_dirty_xattr_block(handle, inode, bh); 551 if (IS_SYNC(inode)) 552 ext4_handle_sync(handle); 553 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1)); 554 ea_bdebug(bh, "refcount now=%d; releasing", 555 le32_to_cpu(BHDR(bh)->h_refcount)); 556 } 557 out: 558 ext4_std_error(inode->i_sb, error); 559 return; 560 } 561 562 /* 563 * Find the available free space for EAs. This also returns the total number of 564 * bytes used by EA entries. 565 */ 566 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last, 567 size_t *min_offs, void *base, int *total) 568 { 569 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 570 *total += EXT4_XATTR_LEN(last->e_name_len); 571 if (!last->e_value_block && last->e_value_size) { 572 size_t offs = le16_to_cpu(last->e_value_offs); 573 if (offs < *min_offs) 574 *min_offs = offs; 575 } 576 } 577 return (*min_offs - ((void *)last - base) - sizeof(__u32)); 578 } 579 580 static int 581 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s) 582 { 583 struct ext4_xattr_entry *last; 584 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name); 585 586 /* Compute min_offs and last. */ 587 last = s->first; 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 } 595 free = min_offs - ((void *)last - s->base) - sizeof(__u32); 596 if (!s->not_found) { 597 if (!s->here->e_value_block && s->here->e_value_size) { 598 size_t size = le32_to_cpu(s->here->e_value_size); 599 free += EXT4_XATTR_SIZE(size); 600 } 601 free += EXT4_XATTR_LEN(name_len); 602 } 603 if (i->value) { 604 if (free < EXT4_XATTR_SIZE(i->value_len) || 605 free < EXT4_XATTR_LEN(name_len) + 606 EXT4_XATTR_SIZE(i->value_len)) 607 return -ENOSPC; 608 } 609 610 if (i->value && s->not_found) { 611 /* Insert the new name. */ 612 size_t size = EXT4_XATTR_LEN(name_len); 613 size_t rest = (void *)last - (void *)s->here + sizeof(__u32); 614 memmove((void *)s->here + size, s->here, rest); 615 memset(s->here, 0, size); 616 s->here->e_name_index = i->name_index; 617 s->here->e_name_len = name_len; 618 memcpy(s->here->e_name, i->name, name_len); 619 } else { 620 if (!s->here->e_value_block && s->here->e_value_size) { 621 void *first_val = s->base + min_offs; 622 size_t offs = le16_to_cpu(s->here->e_value_offs); 623 void *val = s->base + offs; 624 size_t size = EXT4_XATTR_SIZE( 625 le32_to_cpu(s->here->e_value_size)); 626 627 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) { 628 /* The old and the new value have the same 629 size. Just replace. */ 630 s->here->e_value_size = 631 cpu_to_le32(i->value_len); 632 if (i->value == EXT4_ZERO_XATTR_VALUE) { 633 memset(val, 0, size); 634 } else { 635 /* Clear pad bytes first. */ 636 memset(val + size - EXT4_XATTR_PAD, 0, 637 EXT4_XATTR_PAD); 638 memcpy(val, i->value, i->value_len); 639 } 640 return 0; 641 } 642 643 /* Remove the old value. */ 644 memmove(first_val + size, first_val, val - first_val); 645 memset(first_val, 0, size); 646 s->here->e_value_size = 0; 647 s->here->e_value_offs = 0; 648 min_offs += size; 649 650 /* Adjust all value offsets. */ 651 last = s->first; 652 while (!IS_LAST_ENTRY(last)) { 653 size_t o = le16_to_cpu(last->e_value_offs); 654 if (!last->e_value_block && 655 last->e_value_size && o < offs) 656 last->e_value_offs = 657 cpu_to_le16(o + size); 658 last = EXT4_XATTR_NEXT(last); 659 } 660 } 661 if (!i->value) { 662 /* Remove the old name. */ 663 size_t size = EXT4_XATTR_LEN(name_len); 664 last = ENTRY((void *)last - size); 665 memmove(s->here, (void *)s->here + size, 666 (void *)last - (void *)s->here + sizeof(__u32)); 667 memset(last, 0, size); 668 } 669 } 670 671 if (i->value) { 672 /* Insert the new value. */ 673 s->here->e_value_size = cpu_to_le32(i->value_len); 674 if (i->value_len) { 675 size_t size = EXT4_XATTR_SIZE(i->value_len); 676 void *val = s->base + min_offs - size; 677 s->here->e_value_offs = cpu_to_le16(min_offs - size); 678 if (i->value == EXT4_ZERO_XATTR_VALUE) { 679 memset(val, 0, size); 680 } else { 681 /* Clear the pad bytes first. */ 682 memset(val + size - EXT4_XATTR_PAD, 0, 683 EXT4_XATTR_PAD); 684 memcpy(val, i->value, i->value_len); 685 } 686 } 687 } 688 return 0; 689 } 690 691 struct ext4_xattr_block_find { 692 struct ext4_xattr_search s; 693 struct buffer_head *bh; 694 }; 695 696 static int 697 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i, 698 struct ext4_xattr_block_find *bs) 699 { 700 struct super_block *sb = inode->i_sb; 701 int error; 702 703 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", 704 i->name_index, i->name, i->value, (long)i->value_len); 705 706 if (EXT4_I(inode)->i_file_acl) { 707 /* The inode already has an extended attribute block. */ 708 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl); 709 error = -EIO; 710 if (!bs->bh) 711 goto cleanup; 712 ea_bdebug(bs->bh, "b_count=%d, refcount=%d", 713 atomic_read(&(bs->bh->b_count)), 714 le32_to_cpu(BHDR(bs->bh)->h_refcount)); 715 if (ext4_xattr_check_block(inode, bs->bh)) { 716 EXT4_ERROR_INODE(inode, "bad block %llu", 717 EXT4_I(inode)->i_file_acl); 718 error = -EIO; 719 goto cleanup; 720 } 721 /* Find the named attribute. */ 722 bs->s.base = BHDR(bs->bh); 723 bs->s.first = BFIRST(bs->bh); 724 bs->s.end = bs->bh->b_data + bs->bh->b_size; 725 bs->s.here = bs->s.first; 726 error = ext4_xattr_find_entry(&bs->s.here, i->name_index, 727 i->name, bs->bh->b_size, 1); 728 if (error && error != -ENODATA) 729 goto cleanup; 730 bs->s.not_found = error; 731 } 732 error = 0; 733 734 cleanup: 735 return error; 736 } 737 738 static int 739 ext4_xattr_block_set(handle_t *handle, struct inode *inode, 740 struct ext4_xattr_info *i, 741 struct ext4_xattr_block_find *bs) 742 { 743 struct super_block *sb = inode->i_sb; 744 struct buffer_head *new_bh = NULL; 745 struct ext4_xattr_search *s = &bs->s; 746 struct mb_cache_entry *ce = NULL; 747 int error = 0; 748 749 #define header(x) ((struct ext4_xattr_header *)(x)) 750 751 if (i->value && i->value_len > sb->s_blocksize) 752 return -ENOSPC; 753 if (s->base) { 754 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev, 755 bs->bh->b_blocknr); 756 error = ext4_journal_get_write_access(handle, bs->bh); 757 if (error) 758 goto cleanup; 759 lock_buffer(bs->bh); 760 761 if (header(s->base)->h_refcount == cpu_to_le32(1)) { 762 if (ce) { 763 mb_cache_entry_free(ce); 764 ce = NULL; 765 } 766 ea_bdebug(bs->bh, "modifying in-place"); 767 error = ext4_xattr_set_entry(i, s); 768 if (!error) { 769 if (!IS_LAST_ENTRY(s->first)) 770 ext4_xattr_rehash(header(s->base), 771 s->here); 772 ext4_xattr_cache_insert(bs->bh); 773 } 774 unlock_buffer(bs->bh); 775 if (error == -EIO) 776 goto bad_block; 777 if (!error) 778 error = ext4_handle_dirty_xattr_block(handle, 779 inode, 780 bs->bh); 781 if (error) 782 goto cleanup; 783 goto inserted; 784 } else { 785 int offset = (char *)s->here - bs->bh->b_data; 786 787 unlock_buffer(bs->bh); 788 if (ce) { 789 mb_cache_entry_release(ce); 790 ce = NULL; 791 } 792 ea_bdebug(bs->bh, "cloning"); 793 s->base = kmalloc(bs->bh->b_size, GFP_NOFS); 794 error = -ENOMEM; 795 if (s->base == NULL) 796 goto cleanup; 797 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size); 798 s->first = ENTRY(header(s->base)+1); 799 header(s->base)->h_refcount = cpu_to_le32(1); 800 s->here = ENTRY(s->base + offset); 801 s->end = s->base + bs->bh->b_size; 802 } 803 } else { 804 /* Allocate a buffer where we construct the new block. */ 805 s->base = kzalloc(sb->s_blocksize, GFP_NOFS); 806 /* assert(header == s->base) */ 807 error = -ENOMEM; 808 if (s->base == NULL) 809 goto cleanup; 810 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 811 header(s->base)->h_blocks = cpu_to_le32(1); 812 header(s->base)->h_refcount = cpu_to_le32(1); 813 s->first = ENTRY(header(s->base)+1); 814 s->here = ENTRY(header(s->base)+1); 815 s->end = s->base + sb->s_blocksize; 816 } 817 818 error = ext4_xattr_set_entry(i, s); 819 if (error == -EIO) 820 goto bad_block; 821 if (error) 822 goto cleanup; 823 if (!IS_LAST_ENTRY(s->first)) 824 ext4_xattr_rehash(header(s->base), s->here); 825 826 inserted: 827 if (!IS_LAST_ENTRY(s->first)) { 828 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce); 829 if (new_bh) { 830 /* We found an identical block in the cache. */ 831 if (new_bh == bs->bh) 832 ea_bdebug(new_bh, "keeping"); 833 else { 834 /* The old block is released after updating 835 the inode. */ 836 error = dquot_alloc_block(inode, 837 EXT4_C2B(EXT4_SB(sb), 1)); 838 if (error) 839 goto cleanup; 840 error = ext4_journal_get_write_access(handle, 841 new_bh); 842 if (error) 843 goto cleanup_dquot; 844 lock_buffer(new_bh); 845 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1); 846 ea_bdebug(new_bh, "reusing; refcount now=%d", 847 le32_to_cpu(BHDR(new_bh)->h_refcount)); 848 unlock_buffer(new_bh); 849 error = ext4_handle_dirty_xattr_block(handle, 850 inode, 851 new_bh); 852 if (error) 853 goto cleanup_dquot; 854 } 855 mb_cache_entry_release(ce); 856 ce = NULL; 857 } else if (bs->bh && s->base == bs->bh->b_data) { 858 /* We were modifying this block in-place. */ 859 ea_bdebug(bs->bh, "keeping this block"); 860 new_bh = bs->bh; 861 get_bh(new_bh); 862 } else { 863 /* We need to allocate a new block */ 864 ext4_fsblk_t goal, block; 865 866 goal = ext4_group_first_block_no(sb, 867 EXT4_I(inode)->i_block_group); 868 869 /* non-extent files can't have physical blocks past 2^32 */ 870 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 871 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS; 872 873 /* 874 * take i_data_sem because we will test 875 * i_delalloc_reserved_flag in ext4_mb_new_blocks 876 */ 877 down_read((&EXT4_I(inode)->i_data_sem)); 878 block = ext4_new_meta_blocks(handle, inode, goal, 0, 879 NULL, &error); 880 up_read((&EXT4_I(inode)->i_data_sem)); 881 if (error) 882 goto cleanup; 883 884 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 885 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS); 886 887 ea_idebug(inode, "creating block %llu", 888 (unsigned long long)block); 889 890 new_bh = sb_getblk(sb, block); 891 if (unlikely(!new_bh)) { 892 error = -ENOMEM; 893 getblk_failed: 894 ext4_free_blocks(handle, inode, NULL, block, 1, 895 EXT4_FREE_BLOCKS_METADATA); 896 goto cleanup; 897 } 898 lock_buffer(new_bh); 899 error = ext4_journal_get_create_access(handle, new_bh); 900 if (error) { 901 unlock_buffer(new_bh); 902 error = -EIO; 903 goto getblk_failed; 904 } 905 memcpy(new_bh->b_data, s->base, new_bh->b_size); 906 set_buffer_uptodate(new_bh); 907 unlock_buffer(new_bh); 908 ext4_xattr_cache_insert(new_bh); 909 error = ext4_handle_dirty_xattr_block(handle, 910 inode, new_bh); 911 if (error) 912 goto cleanup; 913 } 914 } 915 916 /* Update the inode. */ 917 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; 918 919 /* Drop the previous xattr block. */ 920 if (bs->bh && bs->bh != new_bh) 921 ext4_xattr_release_block(handle, inode, bs->bh); 922 error = 0; 923 924 cleanup: 925 if (ce) 926 mb_cache_entry_release(ce); 927 brelse(new_bh); 928 if (!(bs->bh && s->base == bs->bh->b_data)) 929 kfree(s->base); 930 931 return error; 932 933 cleanup_dquot: 934 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1)); 935 goto cleanup; 936 937 bad_block: 938 EXT4_ERROR_INODE(inode, "bad block %llu", 939 EXT4_I(inode)->i_file_acl); 940 goto cleanup; 941 942 #undef header 943 } 944 945 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, 946 struct ext4_xattr_ibody_find *is) 947 { 948 struct ext4_xattr_ibody_header *header; 949 struct ext4_inode *raw_inode; 950 int error; 951 952 if (EXT4_I(inode)->i_extra_isize == 0) 953 return 0; 954 raw_inode = ext4_raw_inode(&is->iloc); 955 header = IHDR(inode, raw_inode); 956 is->s.base = is->s.first = IFIRST(header); 957 is->s.here = is->s.first; 958 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 959 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { 960 error = ext4_xattr_check_names(IFIRST(header), is->s.end); 961 if (error) 962 return error; 963 /* Find the named attribute. */ 964 error = ext4_xattr_find_entry(&is->s.here, i->name_index, 965 i->name, is->s.end - 966 (void *)is->s.base, 0); 967 if (error && error != -ENODATA) 968 return error; 969 is->s.not_found = error; 970 } 971 return 0; 972 } 973 974 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode, 975 struct ext4_xattr_info *i, 976 struct ext4_xattr_ibody_find *is) 977 { 978 struct ext4_xattr_ibody_header *header; 979 struct ext4_xattr_search *s = &is->s; 980 int error; 981 982 if (EXT4_I(inode)->i_extra_isize == 0) 983 return -ENOSPC; 984 error = ext4_xattr_set_entry(i, s); 985 if (error) { 986 if (error == -ENOSPC && 987 ext4_has_inline_data(inode)) { 988 error = ext4_try_to_evict_inline_data(handle, inode, 989 EXT4_XATTR_LEN(strlen(i->name) + 990 EXT4_XATTR_SIZE(i->value_len))); 991 if (error) 992 return error; 993 error = ext4_xattr_ibody_find(inode, i, is); 994 if (error) 995 return error; 996 error = ext4_xattr_set_entry(i, s); 997 } 998 if (error) 999 return error; 1000 } 1001 header = IHDR(inode, ext4_raw_inode(&is->iloc)); 1002 if (!IS_LAST_ENTRY(s->first)) { 1003 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 1004 ext4_set_inode_state(inode, EXT4_STATE_XATTR); 1005 } else { 1006 header->h_magic = cpu_to_le32(0); 1007 ext4_clear_inode_state(inode, EXT4_STATE_XATTR); 1008 } 1009 return 0; 1010 } 1011 1012 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode, 1013 struct ext4_xattr_info *i, 1014 struct ext4_xattr_ibody_find *is) 1015 { 1016 struct ext4_xattr_ibody_header *header; 1017 struct ext4_xattr_search *s = &is->s; 1018 int error; 1019 1020 if (EXT4_I(inode)->i_extra_isize == 0) 1021 return -ENOSPC; 1022 error = ext4_xattr_set_entry(i, s); 1023 if (error) 1024 return error; 1025 header = IHDR(inode, ext4_raw_inode(&is->iloc)); 1026 if (!IS_LAST_ENTRY(s->first)) { 1027 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 1028 ext4_set_inode_state(inode, EXT4_STATE_XATTR); 1029 } else { 1030 header->h_magic = cpu_to_le32(0); 1031 ext4_clear_inode_state(inode, EXT4_STATE_XATTR); 1032 } 1033 return 0; 1034 } 1035 1036 /* 1037 * ext4_xattr_set_handle() 1038 * 1039 * Create, replace or remove an extended attribute for this inode. Value 1040 * is NULL to remove an existing extended attribute, and non-NULL to 1041 * either replace an existing extended attribute, or create a new extended 1042 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 1043 * specify that an extended attribute must exist and must not exist 1044 * previous to the call, respectively. 1045 * 1046 * Returns 0, or a negative error number on failure. 1047 */ 1048 int 1049 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, 1050 const char *name, const void *value, size_t value_len, 1051 int flags) 1052 { 1053 struct ext4_xattr_info i = { 1054 .name_index = name_index, 1055 .name = name, 1056 .value = value, 1057 .value_len = value_len, 1058 1059 }; 1060 struct ext4_xattr_ibody_find is = { 1061 .s = { .not_found = -ENODATA, }, 1062 }; 1063 struct ext4_xattr_block_find bs = { 1064 .s = { .not_found = -ENODATA, }, 1065 }; 1066 unsigned long no_expand; 1067 int error; 1068 1069 if (!name) 1070 return -EINVAL; 1071 if (strlen(name) > 255) 1072 return -ERANGE; 1073 down_write(&EXT4_I(inode)->xattr_sem); 1074 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND); 1075 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); 1076 1077 error = ext4_reserve_inode_write(handle, inode, &is.iloc); 1078 if (error) 1079 goto cleanup; 1080 1081 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) { 1082 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc); 1083 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); 1084 ext4_clear_inode_state(inode, EXT4_STATE_NEW); 1085 } 1086 1087 error = ext4_xattr_ibody_find(inode, &i, &is); 1088 if (error) 1089 goto cleanup; 1090 if (is.s.not_found) 1091 error = ext4_xattr_block_find(inode, &i, &bs); 1092 if (error) 1093 goto cleanup; 1094 if (is.s.not_found && bs.s.not_found) { 1095 error = -ENODATA; 1096 if (flags & XATTR_REPLACE) 1097 goto cleanup; 1098 error = 0; 1099 if (!value) 1100 goto cleanup; 1101 } else { 1102 error = -EEXIST; 1103 if (flags & XATTR_CREATE) 1104 goto cleanup; 1105 } 1106 if (!value) { 1107 if (!is.s.not_found) 1108 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1109 else if (!bs.s.not_found) 1110 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1111 } else { 1112 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1113 if (!error && !bs.s.not_found) { 1114 i.value = NULL; 1115 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1116 } else if (error == -ENOSPC) { 1117 if (EXT4_I(inode)->i_file_acl && !bs.s.base) { 1118 error = ext4_xattr_block_find(inode, &i, &bs); 1119 if (error) 1120 goto cleanup; 1121 } 1122 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1123 if (error) 1124 goto cleanup; 1125 if (!is.s.not_found) { 1126 i.value = NULL; 1127 error = ext4_xattr_ibody_set(handle, inode, &i, 1128 &is); 1129 } 1130 } 1131 } 1132 if (!error) { 1133 ext4_xattr_update_super_block(handle, inode->i_sb); 1134 inode->i_ctime = ext4_current_time(inode); 1135 if (!value) 1136 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); 1137 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc); 1138 /* 1139 * The bh is consumed by ext4_mark_iloc_dirty, even with 1140 * error != 0. 1141 */ 1142 is.iloc.bh = NULL; 1143 if (IS_SYNC(inode)) 1144 ext4_handle_sync(handle); 1145 } 1146 1147 cleanup: 1148 brelse(is.iloc.bh); 1149 brelse(bs.bh); 1150 if (no_expand == 0) 1151 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); 1152 up_write(&EXT4_I(inode)->xattr_sem); 1153 return error; 1154 } 1155 1156 /* 1157 * ext4_xattr_set() 1158 * 1159 * Like ext4_xattr_set_handle, but start from an inode. This extended 1160 * attribute modification is a filesystem transaction by itself. 1161 * 1162 * Returns 0, or a negative error number on failure. 1163 */ 1164 int 1165 ext4_xattr_set(struct inode *inode, int name_index, const char *name, 1166 const void *value, size_t value_len, int flags) 1167 { 1168 handle_t *handle; 1169 int error, retries = 0; 1170 int credits = ext4_jbd2_credits_xattr(inode); 1171 1172 retry: 1173 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits); 1174 if (IS_ERR(handle)) { 1175 error = PTR_ERR(handle); 1176 } else { 1177 int error2; 1178 1179 error = ext4_xattr_set_handle(handle, inode, name_index, name, 1180 value, value_len, flags); 1181 error2 = ext4_journal_stop(handle); 1182 if (error == -ENOSPC && 1183 ext4_should_retry_alloc(inode->i_sb, &retries)) 1184 goto retry; 1185 if (error == 0) 1186 error = error2; 1187 } 1188 1189 return error; 1190 } 1191 1192 /* 1193 * Shift the EA entries in the inode to create space for the increased 1194 * i_extra_isize. 1195 */ 1196 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry, 1197 int value_offs_shift, void *to, 1198 void *from, size_t n, int blocksize) 1199 { 1200 struct ext4_xattr_entry *last = entry; 1201 int new_offs; 1202 1203 /* Adjust the value offsets of the entries */ 1204 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1205 if (!last->e_value_block && last->e_value_size) { 1206 new_offs = le16_to_cpu(last->e_value_offs) + 1207 value_offs_shift; 1208 BUG_ON(new_offs + le32_to_cpu(last->e_value_size) 1209 > blocksize); 1210 last->e_value_offs = cpu_to_le16(new_offs); 1211 } 1212 } 1213 /* Shift the entries by n bytes */ 1214 memmove(to, from, n); 1215 } 1216 1217 /* 1218 * Expand an inode by new_extra_isize bytes when EAs are present. 1219 * Returns 0 on success or negative error number on failure. 1220 */ 1221 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, 1222 struct ext4_inode *raw_inode, handle_t *handle) 1223 { 1224 struct ext4_xattr_ibody_header *header; 1225 struct ext4_xattr_entry *entry, *last, *first; 1226 struct buffer_head *bh = NULL; 1227 struct ext4_xattr_ibody_find *is = NULL; 1228 struct ext4_xattr_block_find *bs = NULL; 1229 char *buffer = NULL, *b_entry_name = NULL; 1230 size_t min_offs, free; 1231 int total_ino, total_blk; 1232 void *base, *start, *end; 1233 int extra_isize = 0, error = 0, tried_min_extra_isize = 0; 1234 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize); 1235 1236 down_write(&EXT4_I(inode)->xattr_sem); 1237 retry: 1238 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) { 1239 up_write(&EXT4_I(inode)->xattr_sem); 1240 return 0; 1241 } 1242 1243 header = IHDR(inode, raw_inode); 1244 entry = IFIRST(header); 1245 1246 /* 1247 * Check if enough free space is available in the inode to shift the 1248 * entries ahead by new_extra_isize. 1249 */ 1250 1251 base = start = entry; 1252 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 1253 min_offs = end - base; 1254 last = entry; 1255 total_ino = sizeof(struct ext4_xattr_ibody_header); 1256 1257 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino); 1258 if (free >= new_extra_isize) { 1259 entry = IFIRST(header); 1260 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize 1261 - new_extra_isize, (void *)raw_inode + 1262 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize, 1263 (void *)header, total_ino, 1264 inode->i_sb->s_blocksize); 1265 EXT4_I(inode)->i_extra_isize = new_extra_isize; 1266 error = 0; 1267 goto cleanup; 1268 } 1269 1270 /* 1271 * Enough free space isn't available in the inode, check if 1272 * EA block can hold new_extra_isize bytes. 1273 */ 1274 if (EXT4_I(inode)->i_file_acl) { 1275 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1276 error = -EIO; 1277 if (!bh) 1278 goto cleanup; 1279 if (ext4_xattr_check_block(inode, bh)) { 1280 EXT4_ERROR_INODE(inode, "bad block %llu", 1281 EXT4_I(inode)->i_file_acl); 1282 error = -EIO; 1283 goto cleanup; 1284 } 1285 base = BHDR(bh); 1286 first = BFIRST(bh); 1287 end = bh->b_data + bh->b_size; 1288 min_offs = end - base; 1289 free = ext4_xattr_free_space(first, &min_offs, base, 1290 &total_blk); 1291 if (free < new_extra_isize) { 1292 if (!tried_min_extra_isize && s_min_extra_isize) { 1293 tried_min_extra_isize++; 1294 new_extra_isize = s_min_extra_isize; 1295 brelse(bh); 1296 goto retry; 1297 } 1298 error = -1; 1299 goto cleanup; 1300 } 1301 } else { 1302 free = inode->i_sb->s_blocksize; 1303 } 1304 1305 while (new_extra_isize > 0) { 1306 size_t offs, size, entry_size; 1307 struct ext4_xattr_entry *small_entry = NULL; 1308 struct ext4_xattr_info i = { 1309 .value = NULL, 1310 .value_len = 0, 1311 }; 1312 unsigned int total_size; /* EA entry size + value size */ 1313 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */ 1314 unsigned int min_total_size = ~0U; 1315 1316 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS); 1317 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS); 1318 if (!is || !bs) { 1319 error = -ENOMEM; 1320 goto cleanup; 1321 } 1322 1323 is->s.not_found = -ENODATA; 1324 bs->s.not_found = -ENODATA; 1325 is->iloc.bh = NULL; 1326 bs->bh = NULL; 1327 1328 last = IFIRST(header); 1329 /* Find the entry best suited to be pushed into EA block */ 1330 entry = NULL; 1331 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1332 total_size = 1333 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) + 1334 EXT4_XATTR_LEN(last->e_name_len); 1335 if (total_size <= free && total_size < min_total_size) { 1336 if (total_size < new_extra_isize) { 1337 small_entry = last; 1338 } else { 1339 entry = last; 1340 min_total_size = total_size; 1341 } 1342 } 1343 } 1344 1345 if (entry == NULL) { 1346 if (small_entry) { 1347 entry = small_entry; 1348 } else { 1349 if (!tried_min_extra_isize && 1350 s_min_extra_isize) { 1351 tried_min_extra_isize++; 1352 new_extra_isize = s_min_extra_isize; 1353 kfree(is); is = NULL; 1354 kfree(bs); bs = NULL; 1355 goto retry; 1356 } 1357 error = -1; 1358 goto cleanup; 1359 } 1360 } 1361 offs = le16_to_cpu(entry->e_value_offs); 1362 size = le32_to_cpu(entry->e_value_size); 1363 entry_size = EXT4_XATTR_LEN(entry->e_name_len); 1364 i.name_index = entry->e_name_index, 1365 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS); 1366 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS); 1367 if (!buffer || !b_entry_name) { 1368 error = -ENOMEM; 1369 goto cleanup; 1370 } 1371 /* Save the entry name and the entry value */ 1372 memcpy(buffer, (void *)IFIRST(header) + offs, 1373 EXT4_XATTR_SIZE(size)); 1374 memcpy(b_entry_name, entry->e_name, entry->e_name_len); 1375 b_entry_name[entry->e_name_len] = '\0'; 1376 i.name = b_entry_name; 1377 1378 error = ext4_get_inode_loc(inode, &is->iloc); 1379 if (error) 1380 goto cleanup; 1381 1382 error = ext4_xattr_ibody_find(inode, &i, is); 1383 if (error) 1384 goto cleanup; 1385 1386 /* Remove the chosen entry from the inode */ 1387 error = ext4_xattr_ibody_set(handle, inode, &i, is); 1388 if (error) 1389 goto cleanup; 1390 1391 entry = IFIRST(header); 1392 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize) 1393 shift_bytes = new_extra_isize; 1394 else 1395 shift_bytes = entry_size + size; 1396 /* Adjust the offsets and shift the remaining entries ahead */ 1397 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize - 1398 shift_bytes, (void *)raw_inode + 1399 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes, 1400 (void *)header, total_ino - entry_size, 1401 inode->i_sb->s_blocksize); 1402 1403 extra_isize += shift_bytes; 1404 new_extra_isize -= shift_bytes; 1405 EXT4_I(inode)->i_extra_isize = extra_isize; 1406 1407 i.name = b_entry_name; 1408 i.value = buffer; 1409 i.value_len = size; 1410 error = ext4_xattr_block_find(inode, &i, bs); 1411 if (error) 1412 goto cleanup; 1413 1414 /* Add entry which was removed from the inode into the block */ 1415 error = ext4_xattr_block_set(handle, inode, &i, bs); 1416 if (error) 1417 goto cleanup; 1418 kfree(b_entry_name); 1419 kfree(buffer); 1420 b_entry_name = NULL; 1421 buffer = NULL; 1422 brelse(is->iloc.bh); 1423 kfree(is); 1424 kfree(bs); 1425 } 1426 brelse(bh); 1427 up_write(&EXT4_I(inode)->xattr_sem); 1428 return 0; 1429 1430 cleanup: 1431 kfree(b_entry_name); 1432 kfree(buffer); 1433 if (is) 1434 brelse(is->iloc.bh); 1435 kfree(is); 1436 kfree(bs); 1437 brelse(bh); 1438 up_write(&EXT4_I(inode)->xattr_sem); 1439 return error; 1440 } 1441 1442 1443 1444 /* 1445 * ext4_xattr_delete_inode() 1446 * 1447 * Free extended attribute resources associated with this inode. This 1448 * is called immediately before an inode is freed. We have exclusive 1449 * access to the inode. 1450 */ 1451 void 1452 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode) 1453 { 1454 struct buffer_head *bh = NULL; 1455 1456 if (!EXT4_I(inode)->i_file_acl) 1457 goto cleanup; 1458 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1459 if (!bh) { 1460 EXT4_ERROR_INODE(inode, "block %llu read error", 1461 EXT4_I(inode)->i_file_acl); 1462 goto cleanup; 1463 } 1464 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 1465 BHDR(bh)->h_blocks != cpu_to_le32(1)) { 1466 EXT4_ERROR_INODE(inode, "bad block %llu", 1467 EXT4_I(inode)->i_file_acl); 1468 goto cleanup; 1469 } 1470 ext4_xattr_release_block(handle, inode, bh); 1471 EXT4_I(inode)->i_file_acl = 0; 1472 1473 cleanup: 1474 brelse(bh); 1475 } 1476 1477 /* 1478 * ext4_xattr_put_super() 1479 * 1480 * This is called when a file system is unmounted. 1481 */ 1482 void 1483 ext4_xattr_put_super(struct super_block *sb) 1484 { 1485 mb_cache_shrink(sb->s_bdev); 1486 } 1487 1488 /* 1489 * ext4_xattr_cache_insert() 1490 * 1491 * Create a new entry in the extended attribute cache, and insert 1492 * it unless such an entry is already in the cache. 1493 * 1494 * Returns 0, or a negative error number on failure. 1495 */ 1496 static void 1497 ext4_xattr_cache_insert(struct buffer_head *bh) 1498 { 1499 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash); 1500 struct mb_cache_entry *ce; 1501 int error; 1502 1503 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS); 1504 if (!ce) { 1505 ea_bdebug(bh, "out of memory"); 1506 return; 1507 } 1508 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash); 1509 if (error) { 1510 mb_cache_entry_free(ce); 1511 if (error == -EBUSY) { 1512 ea_bdebug(bh, "already in cache"); 1513 error = 0; 1514 } 1515 } else { 1516 ea_bdebug(bh, "inserting [%x]", (int)hash); 1517 mb_cache_entry_release(ce); 1518 } 1519 } 1520 1521 /* 1522 * ext4_xattr_cmp() 1523 * 1524 * Compare two extended attribute blocks for equality. 1525 * 1526 * Returns 0 if the blocks are equal, 1 if they differ, and 1527 * a negative error number on errors. 1528 */ 1529 static int 1530 ext4_xattr_cmp(struct ext4_xattr_header *header1, 1531 struct ext4_xattr_header *header2) 1532 { 1533 struct ext4_xattr_entry *entry1, *entry2; 1534 1535 entry1 = ENTRY(header1+1); 1536 entry2 = ENTRY(header2+1); 1537 while (!IS_LAST_ENTRY(entry1)) { 1538 if (IS_LAST_ENTRY(entry2)) 1539 return 1; 1540 if (entry1->e_hash != entry2->e_hash || 1541 entry1->e_name_index != entry2->e_name_index || 1542 entry1->e_name_len != entry2->e_name_len || 1543 entry1->e_value_size != entry2->e_value_size || 1544 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) 1545 return 1; 1546 if (entry1->e_value_block != 0 || entry2->e_value_block != 0) 1547 return -EIO; 1548 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), 1549 (char *)header2 + le16_to_cpu(entry2->e_value_offs), 1550 le32_to_cpu(entry1->e_value_size))) 1551 return 1; 1552 1553 entry1 = EXT4_XATTR_NEXT(entry1); 1554 entry2 = EXT4_XATTR_NEXT(entry2); 1555 } 1556 if (!IS_LAST_ENTRY(entry2)) 1557 return 1; 1558 return 0; 1559 } 1560 1561 /* 1562 * ext4_xattr_cache_find() 1563 * 1564 * Find an identical extended attribute block. 1565 * 1566 * Returns a pointer to the block found, or NULL if such a block was 1567 * not found or an error occurred. 1568 */ 1569 static struct buffer_head * 1570 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header, 1571 struct mb_cache_entry **pce) 1572 { 1573 __u32 hash = le32_to_cpu(header->h_hash); 1574 struct mb_cache_entry *ce; 1575 1576 if (!header->h_hash) 1577 return NULL; /* never share */ 1578 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); 1579 again: 1580 ce = mb_cache_entry_find_first(ext4_xattr_cache, inode->i_sb->s_bdev, 1581 hash); 1582 while (ce) { 1583 struct buffer_head *bh; 1584 1585 if (IS_ERR(ce)) { 1586 if (PTR_ERR(ce) == -EAGAIN) 1587 goto again; 1588 break; 1589 } 1590 bh = sb_bread(inode->i_sb, ce->e_block); 1591 if (!bh) { 1592 EXT4_ERROR_INODE(inode, "block %lu read error", 1593 (unsigned long) ce->e_block); 1594 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >= 1595 EXT4_XATTR_REFCOUNT_MAX) { 1596 ea_idebug(inode, "block %lu refcount %d>=%d", 1597 (unsigned long) ce->e_block, 1598 le32_to_cpu(BHDR(bh)->h_refcount), 1599 EXT4_XATTR_REFCOUNT_MAX); 1600 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) { 1601 *pce = ce; 1602 return bh; 1603 } 1604 brelse(bh); 1605 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash); 1606 } 1607 return NULL; 1608 } 1609 1610 #define NAME_HASH_SHIFT 5 1611 #define VALUE_HASH_SHIFT 16 1612 1613 /* 1614 * ext4_xattr_hash_entry() 1615 * 1616 * Compute the hash of an extended attribute. 1617 */ 1618 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header, 1619 struct ext4_xattr_entry *entry) 1620 { 1621 __u32 hash = 0; 1622 char *name = entry->e_name; 1623 int n; 1624 1625 for (n = 0; n < entry->e_name_len; n++) { 1626 hash = (hash << NAME_HASH_SHIFT) ^ 1627 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ 1628 *name++; 1629 } 1630 1631 if (entry->e_value_block == 0 && entry->e_value_size != 0) { 1632 __le32 *value = (__le32 *)((char *)header + 1633 le16_to_cpu(entry->e_value_offs)); 1634 for (n = (le32_to_cpu(entry->e_value_size) + 1635 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) { 1636 hash = (hash << VALUE_HASH_SHIFT) ^ 1637 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ 1638 le32_to_cpu(*value++); 1639 } 1640 } 1641 entry->e_hash = cpu_to_le32(hash); 1642 } 1643 1644 #undef NAME_HASH_SHIFT 1645 #undef VALUE_HASH_SHIFT 1646 1647 #define BLOCK_HASH_SHIFT 16 1648 1649 /* 1650 * ext4_xattr_rehash() 1651 * 1652 * Re-compute the extended attribute hash value after an entry has changed. 1653 */ 1654 static void ext4_xattr_rehash(struct ext4_xattr_header *header, 1655 struct ext4_xattr_entry *entry) 1656 { 1657 struct ext4_xattr_entry *here; 1658 __u32 hash = 0; 1659 1660 ext4_xattr_hash_entry(header, entry); 1661 here = ENTRY(header+1); 1662 while (!IS_LAST_ENTRY(here)) { 1663 if (!here->e_hash) { 1664 /* Block is not shared if an entry's hash value == 0 */ 1665 hash = 0; 1666 break; 1667 } 1668 hash = (hash << BLOCK_HASH_SHIFT) ^ 1669 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ 1670 le32_to_cpu(here->e_hash); 1671 here = EXT4_XATTR_NEXT(here); 1672 } 1673 header->h_hash = cpu_to_le32(hash); 1674 } 1675 1676 #undef BLOCK_HASH_SHIFT 1677 1678 int __init 1679 ext4_init_xattr(void) 1680 { 1681 ext4_xattr_cache = mb_cache_create("ext4_xattr", 6); 1682 if (!ext4_xattr_cache) 1683 return -ENOMEM; 1684 return 0; 1685 } 1686 1687 void 1688 ext4_exit_xattr(void) 1689 { 1690 if (ext4_xattr_cache) 1691 mb_cache_destroy(ext4_xattr_cache); 1692 ext4_xattr_cache = NULL; 1693 } 1694