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 "ext4_jbd2.h" 59 #include "ext4.h" 60 #include "xattr.h" 61 #include "acl.h" 62 63 #ifdef EXT4_XATTR_DEBUG 64 # define ea_idebug(inode, fmt, ...) \ 65 printk(KERN_DEBUG "inode %s:%lu: " fmt "\n", \ 66 inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__) 67 # define ea_bdebug(bh, fmt, ...) \ 68 printk(KERN_DEBUG "block %pg:%lu: " fmt "\n", \ 69 bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__) 70 #else 71 # define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__) 72 # define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__) 73 #endif 74 75 static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *); 76 static struct buffer_head *ext4_xattr_cache_find(struct inode *, 77 struct ext4_xattr_header *, 78 struct mb_cache_entry **); 79 static void ext4_xattr_rehash(struct ext4_xattr_header *, 80 struct ext4_xattr_entry *); 81 static int ext4_xattr_list(struct dentry *dentry, char *buffer, 82 size_t buffer_size); 83 84 static const struct xattr_handler *ext4_xattr_handler_map[] = { 85 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler, 86 #ifdef CONFIG_EXT4_FS_POSIX_ACL 87 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler, 88 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler, 89 #endif 90 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler, 91 #ifdef CONFIG_EXT4_FS_SECURITY 92 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler, 93 #endif 94 }; 95 96 const struct xattr_handler *ext4_xattr_handlers[] = { 97 &ext4_xattr_user_handler, 98 &ext4_xattr_trusted_handler, 99 #ifdef CONFIG_EXT4_FS_POSIX_ACL 100 &posix_acl_access_xattr_handler, 101 &posix_acl_default_xattr_handler, 102 #endif 103 #ifdef CONFIG_EXT4_FS_SECURITY 104 &ext4_xattr_security_handler, 105 #endif 106 NULL 107 }; 108 109 #define EXT4_GET_MB_CACHE(inode) (((struct ext4_sb_info *) \ 110 inode->i_sb->s_fs_info)->s_mb_cache) 111 112 static __le32 ext4_xattr_block_csum(struct inode *inode, 113 sector_t block_nr, 114 struct ext4_xattr_header *hdr) 115 { 116 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 117 __u32 csum; 118 __le64 dsk_block_nr = cpu_to_le64(block_nr); 119 __u32 dummy_csum = 0; 120 int offset = offsetof(struct ext4_xattr_header, h_checksum); 121 122 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr, 123 sizeof(dsk_block_nr)); 124 csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset); 125 csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum)); 126 offset += sizeof(dummy_csum); 127 csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset, 128 EXT4_BLOCK_SIZE(inode->i_sb) - offset); 129 130 return cpu_to_le32(csum); 131 } 132 133 static int ext4_xattr_block_csum_verify(struct inode *inode, 134 sector_t block_nr, 135 struct ext4_xattr_header *hdr) 136 { 137 if (ext4_has_metadata_csum(inode->i_sb) && 138 (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr))) 139 return 0; 140 return 1; 141 } 142 143 static void ext4_xattr_block_csum_set(struct inode *inode, 144 sector_t block_nr, 145 struct ext4_xattr_header *hdr) 146 { 147 if (!ext4_has_metadata_csum(inode->i_sb)) 148 return; 149 150 hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr); 151 } 152 153 static inline int ext4_handle_dirty_xattr_block(handle_t *handle, 154 struct inode *inode, 155 struct buffer_head *bh) 156 { 157 ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh)); 158 return ext4_handle_dirty_metadata(handle, inode, bh); 159 } 160 161 static inline const struct xattr_handler * 162 ext4_xattr_handler(int name_index) 163 { 164 const struct xattr_handler *handler = NULL; 165 166 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map)) 167 handler = ext4_xattr_handler_map[name_index]; 168 return handler; 169 } 170 171 /* 172 * Inode operation listxattr() 173 * 174 * d_inode(dentry)->i_mutex: don't care 175 */ 176 ssize_t 177 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size) 178 { 179 return ext4_xattr_list(dentry, buffer, size); 180 } 181 182 static int 183 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end, 184 void *value_start) 185 { 186 struct ext4_xattr_entry *e = entry; 187 188 while (!IS_LAST_ENTRY(e)) { 189 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e); 190 if ((void *)next >= end) 191 return -EFSCORRUPTED; 192 e = next; 193 } 194 195 while (!IS_LAST_ENTRY(entry)) { 196 if (entry->e_value_block != 0) 197 return -EFSCORRUPTED; 198 if (entry->e_value_size != 0 && 199 (value_start + le16_to_cpu(entry->e_value_offs) < 200 (void *)e + sizeof(__u32) || 201 value_start + le16_to_cpu(entry->e_value_offs) + 202 le32_to_cpu(entry->e_value_size) > end)) 203 return -EFSCORRUPTED; 204 entry = EXT4_XATTR_NEXT(entry); 205 } 206 207 return 0; 208 } 209 210 static inline int 211 ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh) 212 { 213 int error; 214 215 if (buffer_verified(bh)) 216 return 0; 217 218 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 219 BHDR(bh)->h_blocks != cpu_to_le32(1)) 220 return -EFSCORRUPTED; 221 if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh))) 222 return -EFSBADCRC; 223 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size, 224 bh->b_data); 225 if (!error) 226 set_buffer_verified(bh); 227 return error; 228 } 229 230 static int 231 __xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header, 232 void *end, const char *function, unsigned int line) 233 { 234 struct ext4_xattr_entry *entry = IFIRST(header); 235 int error = -EFSCORRUPTED; 236 237 if (((void *) header >= end) || 238 (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC))) 239 goto errout; 240 error = ext4_xattr_check_names(entry, end, entry); 241 errout: 242 if (error) 243 __ext4_error_inode(inode, function, line, 0, 244 "corrupted in-inode xattr"); 245 return error; 246 } 247 248 #define xattr_check_inode(inode, header, end) \ 249 __xattr_check_inode((inode), (header), (end), __func__, __LINE__) 250 251 static inline int 252 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size) 253 { 254 size_t value_size = le32_to_cpu(entry->e_value_size); 255 256 if (entry->e_value_block != 0 || value_size > size || 257 le16_to_cpu(entry->e_value_offs) + value_size > size) 258 return -EFSCORRUPTED; 259 return 0; 260 } 261 262 static int 263 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index, 264 const char *name, size_t size, int sorted) 265 { 266 struct ext4_xattr_entry *entry; 267 size_t name_len; 268 int cmp = 1; 269 270 if (name == NULL) 271 return -EINVAL; 272 name_len = strlen(name); 273 entry = *pentry; 274 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 275 cmp = name_index - entry->e_name_index; 276 if (!cmp) 277 cmp = name_len - entry->e_name_len; 278 if (!cmp) 279 cmp = memcmp(name, entry->e_name, name_len); 280 if (cmp <= 0 && (sorted || cmp == 0)) 281 break; 282 } 283 *pentry = entry; 284 if (!cmp && ext4_xattr_check_entry(entry, size)) 285 return -EFSCORRUPTED; 286 return cmp ? -ENODATA : 0; 287 } 288 289 static int 290 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name, 291 void *buffer, size_t buffer_size) 292 { 293 struct buffer_head *bh = NULL; 294 struct ext4_xattr_entry *entry; 295 size_t size; 296 int error; 297 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 298 299 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", 300 name_index, name, buffer, (long)buffer_size); 301 302 error = -ENODATA; 303 if (!EXT4_I(inode)->i_file_acl) 304 goto cleanup; 305 ea_idebug(inode, "reading block %llu", 306 (unsigned long long)EXT4_I(inode)->i_file_acl); 307 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 308 if (!bh) 309 goto cleanup; 310 ea_bdebug(bh, "b_count=%d, refcount=%d", 311 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 312 if (ext4_xattr_check_block(inode, bh)) { 313 bad_block: 314 EXT4_ERROR_INODE(inode, "bad block %llu", 315 EXT4_I(inode)->i_file_acl); 316 error = -EFSCORRUPTED; 317 goto cleanup; 318 } 319 ext4_xattr_cache_insert(ext4_mb_cache, bh); 320 entry = BFIRST(bh); 321 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1); 322 if (error == -EFSCORRUPTED) 323 goto bad_block; 324 if (error) 325 goto cleanup; 326 size = le32_to_cpu(entry->e_value_size); 327 if (buffer) { 328 error = -ERANGE; 329 if (size > buffer_size) 330 goto cleanup; 331 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), 332 size); 333 } 334 error = size; 335 336 cleanup: 337 brelse(bh); 338 return error; 339 } 340 341 int 342 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name, 343 void *buffer, size_t buffer_size) 344 { 345 struct ext4_xattr_ibody_header *header; 346 struct ext4_xattr_entry *entry; 347 struct ext4_inode *raw_inode; 348 struct ext4_iloc iloc; 349 size_t size; 350 void *end; 351 int error; 352 353 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR)) 354 return -ENODATA; 355 error = ext4_get_inode_loc(inode, &iloc); 356 if (error) 357 return error; 358 raw_inode = ext4_raw_inode(&iloc); 359 header = IHDR(inode, raw_inode); 360 entry = IFIRST(header); 361 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 362 error = xattr_check_inode(inode, header, end); 363 if (error) 364 goto cleanup; 365 error = ext4_xattr_find_entry(&entry, name_index, name, 366 end - (void *)entry, 0); 367 if (error) 368 goto cleanup; 369 size = le32_to_cpu(entry->e_value_size); 370 if (buffer) { 371 error = -ERANGE; 372 if (size > buffer_size) 373 goto cleanup; 374 memcpy(buffer, (void *)IFIRST(header) + 375 le16_to_cpu(entry->e_value_offs), size); 376 } 377 error = size; 378 379 cleanup: 380 brelse(iloc.bh); 381 return error; 382 } 383 384 /* 385 * ext4_xattr_get() 386 * 387 * Copy an extended attribute into the buffer 388 * provided, or compute the buffer size required. 389 * Buffer is NULL to compute the size of the buffer required. 390 * 391 * Returns a negative error number on failure, or the number of bytes 392 * used / required on success. 393 */ 394 int 395 ext4_xattr_get(struct inode *inode, int name_index, const char *name, 396 void *buffer, size_t buffer_size) 397 { 398 int error; 399 400 if (strlen(name) > 255) 401 return -ERANGE; 402 403 down_read(&EXT4_I(inode)->xattr_sem); 404 error = ext4_xattr_ibody_get(inode, name_index, name, buffer, 405 buffer_size); 406 if (error == -ENODATA) 407 error = ext4_xattr_block_get(inode, name_index, name, buffer, 408 buffer_size); 409 up_read(&EXT4_I(inode)->xattr_sem); 410 return error; 411 } 412 413 static int 414 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry, 415 char *buffer, size_t buffer_size) 416 { 417 size_t rest = buffer_size; 418 419 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 420 const struct xattr_handler *handler = 421 ext4_xattr_handler(entry->e_name_index); 422 423 if (handler && (!handler->list || handler->list(dentry))) { 424 const char *prefix = handler->prefix ?: handler->name; 425 size_t prefix_len = strlen(prefix); 426 size_t size = prefix_len + entry->e_name_len + 1; 427 428 if (buffer) { 429 if (size > rest) 430 return -ERANGE; 431 memcpy(buffer, prefix, prefix_len); 432 buffer += prefix_len; 433 memcpy(buffer, entry->e_name, entry->e_name_len); 434 buffer += entry->e_name_len; 435 *buffer++ = 0; 436 } 437 rest -= size; 438 } 439 } 440 return buffer_size - rest; /* total size */ 441 } 442 443 static int 444 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size) 445 { 446 struct inode *inode = d_inode(dentry); 447 struct buffer_head *bh = NULL; 448 int error; 449 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 450 451 ea_idebug(inode, "buffer=%p, buffer_size=%ld", 452 buffer, (long)buffer_size); 453 454 error = 0; 455 if (!EXT4_I(inode)->i_file_acl) 456 goto cleanup; 457 ea_idebug(inode, "reading block %llu", 458 (unsigned long long)EXT4_I(inode)->i_file_acl); 459 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 460 error = -EIO; 461 if (!bh) 462 goto cleanup; 463 ea_bdebug(bh, "b_count=%d, refcount=%d", 464 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 465 if (ext4_xattr_check_block(inode, bh)) { 466 EXT4_ERROR_INODE(inode, "bad block %llu", 467 EXT4_I(inode)->i_file_acl); 468 error = -EFSCORRUPTED; 469 goto cleanup; 470 } 471 ext4_xattr_cache_insert(ext4_mb_cache, bh); 472 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size); 473 474 cleanup: 475 brelse(bh); 476 477 return error; 478 } 479 480 static int 481 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size) 482 { 483 struct inode *inode = d_inode(dentry); 484 struct ext4_xattr_ibody_header *header; 485 struct ext4_inode *raw_inode; 486 struct ext4_iloc iloc; 487 void *end; 488 int error; 489 490 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR)) 491 return 0; 492 error = ext4_get_inode_loc(inode, &iloc); 493 if (error) 494 return error; 495 raw_inode = ext4_raw_inode(&iloc); 496 header = IHDR(inode, raw_inode); 497 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 498 error = xattr_check_inode(inode, header, end); 499 if (error) 500 goto cleanup; 501 error = ext4_xattr_list_entries(dentry, IFIRST(header), 502 buffer, buffer_size); 503 504 cleanup: 505 brelse(iloc.bh); 506 return error; 507 } 508 509 /* 510 * ext4_xattr_list() 511 * 512 * Copy a list of attribute names into the buffer 513 * provided, or compute the buffer size required. 514 * Buffer is NULL to compute the size of the buffer required. 515 * 516 * Returns a negative error number on failure, or the number of bytes 517 * used / required on success. 518 */ 519 static int 520 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size) 521 { 522 int ret, ret2; 523 524 down_read(&EXT4_I(d_inode(dentry))->xattr_sem); 525 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size); 526 if (ret < 0) 527 goto errout; 528 if (buffer) { 529 buffer += ret; 530 buffer_size -= ret; 531 } 532 ret = ext4_xattr_block_list(dentry, buffer, buffer_size); 533 if (ret < 0) 534 goto errout; 535 ret += ret2; 536 errout: 537 up_read(&EXT4_I(d_inode(dentry))->xattr_sem); 538 return ret; 539 } 540 541 /* 542 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is 543 * not set, set it. 544 */ 545 static void ext4_xattr_update_super_block(handle_t *handle, 546 struct super_block *sb) 547 { 548 if (ext4_has_feature_xattr(sb)) 549 return; 550 551 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access"); 552 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) { 553 ext4_set_feature_xattr(sb); 554 ext4_handle_dirty_super(handle, sb); 555 } 556 } 557 558 /* 559 * Release the xattr block BH: If the reference count is > 1, decrement it; 560 * otherwise free the block. 561 */ 562 static void 563 ext4_xattr_release_block(handle_t *handle, struct inode *inode, 564 struct buffer_head *bh) 565 { 566 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 567 u32 hash, ref; 568 int error = 0; 569 570 BUFFER_TRACE(bh, "get_write_access"); 571 error = ext4_journal_get_write_access(handle, bh); 572 if (error) 573 goto out; 574 575 lock_buffer(bh); 576 hash = le32_to_cpu(BHDR(bh)->h_hash); 577 ref = le32_to_cpu(BHDR(bh)->h_refcount); 578 if (ref == 1) { 579 ea_bdebug(bh, "refcount now=0; freeing"); 580 /* 581 * This must happen under buffer lock for 582 * ext4_xattr_block_set() to reliably detect freed block 583 */ 584 mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr); 585 get_bh(bh); 586 unlock_buffer(bh); 587 ext4_free_blocks(handle, inode, bh, 0, 1, 588 EXT4_FREE_BLOCKS_METADATA | 589 EXT4_FREE_BLOCKS_FORGET); 590 } else { 591 ref--; 592 BHDR(bh)->h_refcount = cpu_to_le32(ref); 593 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) { 594 struct mb_cache_entry *ce; 595 596 ce = mb_cache_entry_get(ext4_mb_cache, hash, 597 bh->b_blocknr); 598 if (ce) { 599 ce->e_reusable = 1; 600 mb_cache_entry_put(ext4_mb_cache, ce); 601 } 602 } 603 604 /* 605 * Beware of this ugliness: Releasing of xattr block references 606 * from different inodes can race and so we have to protect 607 * from a race where someone else frees the block (and releases 608 * its journal_head) before we are done dirtying the buffer. In 609 * nojournal mode this race is harmless and we actually cannot 610 * call ext4_handle_dirty_xattr_block() with locked buffer as 611 * that function can call sync_dirty_buffer() so for that case 612 * we handle the dirtying after unlocking the buffer. 613 */ 614 if (ext4_handle_valid(handle)) 615 error = ext4_handle_dirty_xattr_block(handle, inode, 616 bh); 617 unlock_buffer(bh); 618 if (!ext4_handle_valid(handle)) 619 error = ext4_handle_dirty_xattr_block(handle, inode, 620 bh); 621 if (IS_SYNC(inode)) 622 ext4_handle_sync(handle); 623 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1)); 624 ea_bdebug(bh, "refcount now=%d; releasing", 625 le32_to_cpu(BHDR(bh)->h_refcount)); 626 } 627 out: 628 ext4_std_error(inode->i_sb, error); 629 return; 630 } 631 632 /* 633 * Find the available free space for EAs. This also returns the total number of 634 * bytes used by EA entries. 635 */ 636 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last, 637 size_t *min_offs, void *base, int *total) 638 { 639 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 640 if (last->e_value_size) { 641 size_t offs = le16_to_cpu(last->e_value_offs); 642 if (offs < *min_offs) 643 *min_offs = offs; 644 } 645 if (total) 646 *total += EXT4_XATTR_LEN(last->e_name_len); 647 } 648 return (*min_offs - ((void *)last - base) - sizeof(__u32)); 649 } 650 651 static int 652 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s) 653 { 654 struct ext4_xattr_entry *last; 655 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name); 656 657 /* Compute min_offs and last. */ 658 last = s->first; 659 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 660 if (last->e_value_size) { 661 size_t offs = le16_to_cpu(last->e_value_offs); 662 if (offs < min_offs) 663 min_offs = offs; 664 } 665 } 666 free = min_offs - ((void *)last - s->base) - sizeof(__u32); 667 if (!s->not_found) { 668 if (s->here->e_value_size) { 669 size_t size = le32_to_cpu(s->here->e_value_size); 670 free += EXT4_XATTR_SIZE(size); 671 } 672 free += EXT4_XATTR_LEN(name_len); 673 } 674 if (i->value) { 675 if (free < EXT4_XATTR_LEN(name_len) + 676 EXT4_XATTR_SIZE(i->value_len)) 677 return -ENOSPC; 678 } 679 680 if (i->value && s->not_found) { 681 /* Insert the new name. */ 682 size_t size = EXT4_XATTR_LEN(name_len); 683 size_t rest = (void *)last - (void *)s->here + sizeof(__u32); 684 memmove((void *)s->here + size, s->here, rest); 685 memset(s->here, 0, size); 686 s->here->e_name_index = i->name_index; 687 s->here->e_name_len = name_len; 688 memcpy(s->here->e_name, i->name, name_len); 689 } else { 690 if (s->here->e_value_size) { 691 void *first_val = s->base + min_offs; 692 size_t offs = le16_to_cpu(s->here->e_value_offs); 693 void *val = s->base + offs; 694 size_t size = EXT4_XATTR_SIZE( 695 le32_to_cpu(s->here->e_value_size)); 696 697 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) { 698 /* The old and the new value have the same 699 size. Just replace. */ 700 s->here->e_value_size = 701 cpu_to_le32(i->value_len); 702 if (i->value == EXT4_ZERO_XATTR_VALUE) { 703 memset(val, 0, size); 704 } else { 705 /* Clear pad bytes first. */ 706 memset(val + size - EXT4_XATTR_PAD, 0, 707 EXT4_XATTR_PAD); 708 memcpy(val, i->value, i->value_len); 709 } 710 return 0; 711 } 712 713 /* Remove the old value. */ 714 memmove(first_val + size, first_val, val - first_val); 715 memset(first_val, 0, size); 716 s->here->e_value_size = 0; 717 s->here->e_value_offs = 0; 718 min_offs += size; 719 720 /* Adjust all value offsets. */ 721 last = s->first; 722 while (!IS_LAST_ENTRY(last)) { 723 size_t o = le16_to_cpu(last->e_value_offs); 724 if (last->e_value_size && o < offs) 725 last->e_value_offs = 726 cpu_to_le16(o + size); 727 last = EXT4_XATTR_NEXT(last); 728 } 729 } 730 if (!i->value) { 731 /* Remove the old name. */ 732 size_t size = EXT4_XATTR_LEN(name_len); 733 last = ENTRY((void *)last - size); 734 memmove(s->here, (void *)s->here + size, 735 (void *)last - (void *)s->here + sizeof(__u32)); 736 memset(last, 0, size); 737 } 738 } 739 740 if (i->value) { 741 /* Insert the new value. */ 742 s->here->e_value_size = cpu_to_le32(i->value_len); 743 if (i->value_len) { 744 size_t size = EXT4_XATTR_SIZE(i->value_len); 745 void *val = s->base + min_offs - size; 746 s->here->e_value_offs = cpu_to_le16(min_offs - size); 747 if (i->value == EXT4_ZERO_XATTR_VALUE) { 748 memset(val, 0, size); 749 } else { 750 /* Clear the pad bytes first. */ 751 memset(val + size - EXT4_XATTR_PAD, 0, 752 EXT4_XATTR_PAD); 753 memcpy(val, i->value, i->value_len); 754 } 755 } 756 } 757 return 0; 758 } 759 760 struct ext4_xattr_block_find { 761 struct ext4_xattr_search s; 762 struct buffer_head *bh; 763 }; 764 765 static int 766 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i, 767 struct ext4_xattr_block_find *bs) 768 { 769 struct super_block *sb = inode->i_sb; 770 int error; 771 772 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", 773 i->name_index, i->name, i->value, (long)i->value_len); 774 775 if (EXT4_I(inode)->i_file_acl) { 776 /* The inode already has an extended attribute block. */ 777 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl); 778 error = -EIO; 779 if (!bs->bh) 780 goto cleanup; 781 ea_bdebug(bs->bh, "b_count=%d, refcount=%d", 782 atomic_read(&(bs->bh->b_count)), 783 le32_to_cpu(BHDR(bs->bh)->h_refcount)); 784 if (ext4_xattr_check_block(inode, bs->bh)) { 785 EXT4_ERROR_INODE(inode, "bad block %llu", 786 EXT4_I(inode)->i_file_acl); 787 error = -EFSCORRUPTED; 788 goto cleanup; 789 } 790 /* Find the named attribute. */ 791 bs->s.base = BHDR(bs->bh); 792 bs->s.first = BFIRST(bs->bh); 793 bs->s.end = bs->bh->b_data + bs->bh->b_size; 794 bs->s.here = bs->s.first; 795 error = ext4_xattr_find_entry(&bs->s.here, i->name_index, 796 i->name, bs->bh->b_size, 1); 797 if (error && error != -ENODATA) 798 goto cleanup; 799 bs->s.not_found = error; 800 } 801 error = 0; 802 803 cleanup: 804 return error; 805 } 806 807 static int 808 ext4_xattr_block_set(handle_t *handle, struct inode *inode, 809 struct ext4_xattr_info *i, 810 struct ext4_xattr_block_find *bs) 811 { 812 struct super_block *sb = inode->i_sb; 813 struct buffer_head *new_bh = NULL; 814 struct ext4_xattr_search *s = &bs->s; 815 struct mb_cache_entry *ce = NULL; 816 int error = 0; 817 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 818 819 #define header(x) ((struct ext4_xattr_header *)(x)) 820 821 if (i->value && i->value_len > sb->s_blocksize) 822 return -ENOSPC; 823 if (s->base) { 824 BUFFER_TRACE(bs->bh, "get_write_access"); 825 error = ext4_journal_get_write_access(handle, bs->bh); 826 if (error) 827 goto cleanup; 828 lock_buffer(bs->bh); 829 830 if (header(s->base)->h_refcount == cpu_to_le32(1)) { 831 __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash); 832 833 /* 834 * This must happen under buffer lock for 835 * ext4_xattr_block_set() to reliably detect modified 836 * block 837 */ 838 mb_cache_entry_delete_block(ext4_mb_cache, hash, 839 bs->bh->b_blocknr); 840 ea_bdebug(bs->bh, "modifying in-place"); 841 error = ext4_xattr_set_entry(i, s); 842 if (!error) { 843 if (!IS_LAST_ENTRY(s->first)) 844 ext4_xattr_rehash(header(s->base), 845 s->here); 846 ext4_xattr_cache_insert(ext4_mb_cache, 847 bs->bh); 848 } 849 unlock_buffer(bs->bh); 850 if (error == -EFSCORRUPTED) 851 goto bad_block; 852 if (!error) 853 error = ext4_handle_dirty_xattr_block(handle, 854 inode, 855 bs->bh); 856 if (error) 857 goto cleanup; 858 goto inserted; 859 } else { 860 int offset = (char *)s->here - bs->bh->b_data; 861 862 unlock_buffer(bs->bh); 863 ea_bdebug(bs->bh, "cloning"); 864 s->base = kmalloc(bs->bh->b_size, GFP_NOFS); 865 error = -ENOMEM; 866 if (s->base == NULL) 867 goto cleanup; 868 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size); 869 s->first = ENTRY(header(s->base)+1); 870 header(s->base)->h_refcount = cpu_to_le32(1); 871 s->here = ENTRY(s->base + offset); 872 s->end = s->base + bs->bh->b_size; 873 } 874 } else { 875 /* Allocate a buffer where we construct the new block. */ 876 s->base = kzalloc(sb->s_blocksize, GFP_NOFS); 877 /* assert(header == s->base) */ 878 error = -ENOMEM; 879 if (s->base == NULL) 880 goto cleanup; 881 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 882 header(s->base)->h_blocks = cpu_to_le32(1); 883 header(s->base)->h_refcount = cpu_to_le32(1); 884 s->first = ENTRY(header(s->base)+1); 885 s->here = ENTRY(header(s->base)+1); 886 s->end = s->base + sb->s_blocksize; 887 } 888 889 error = ext4_xattr_set_entry(i, s); 890 if (error == -EFSCORRUPTED) 891 goto bad_block; 892 if (error) 893 goto cleanup; 894 if (!IS_LAST_ENTRY(s->first)) 895 ext4_xattr_rehash(header(s->base), s->here); 896 897 inserted: 898 if (!IS_LAST_ENTRY(s->first)) { 899 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce); 900 if (new_bh) { 901 /* We found an identical block in the cache. */ 902 if (new_bh == bs->bh) 903 ea_bdebug(new_bh, "keeping"); 904 else { 905 u32 ref; 906 907 /* The old block is released after updating 908 the inode. */ 909 error = dquot_alloc_block(inode, 910 EXT4_C2B(EXT4_SB(sb), 1)); 911 if (error) 912 goto cleanup; 913 BUFFER_TRACE(new_bh, "get_write_access"); 914 error = ext4_journal_get_write_access(handle, 915 new_bh); 916 if (error) 917 goto cleanup_dquot; 918 lock_buffer(new_bh); 919 /* 920 * We have to be careful about races with 921 * freeing, rehashing or adding references to 922 * xattr block. Once we hold buffer lock xattr 923 * block's state is stable so we can check 924 * whether the block got freed / rehashed or 925 * not. Since we unhash mbcache entry under 926 * buffer lock when freeing / rehashing xattr 927 * block, checking whether entry is still 928 * hashed is reliable. Same rules hold for 929 * e_reusable handling. 930 */ 931 if (hlist_bl_unhashed(&ce->e_hash_list) || 932 !ce->e_reusable) { 933 /* 934 * Undo everything and check mbcache 935 * again. 936 */ 937 unlock_buffer(new_bh); 938 dquot_free_block(inode, 939 EXT4_C2B(EXT4_SB(sb), 940 1)); 941 brelse(new_bh); 942 mb_cache_entry_put(ext4_mb_cache, ce); 943 ce = NULL; 944 new_bh = NULL; 945 goto inserted; 946 } 947 ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1; 948 BHDR(new_bh)->h_refcount = cpu_to_le32(ref); 949 if (ref >= EXT4_XATTR_REFCOUNT_MAX) 950 ce->e_reusable = 0; 951 ea_bdebug(new_bh, "reusing; refcount now=%d", 952 ref); 953 unlock_buffer(new_bh); 954 error = ext4_handle_dirty_xattr_block(handle, 955 inode, 956 new_bh); 957 if (error) 958 goto cleanup_dquot; 959 } 960 mb_cache_entry_touch(ext4_mb_cache, ce); 961 mb_cache_entry_put(ext4_mb_cache, ce); 962 ce = NULL; 963 } else if (bs->bh && s->base == bs->bh->b_data) { 964 /* We were modifying this block in-place. */ 965 ea_bdebug(bs->bh, "keeping this block"); 966 new_bh = bs->bh; 967 get_bh(new_bh); 968 } else { 969 /* We need to allocate a new block */ 970 ext4_fsblk_t goal, block; 971 972 goal = ext4_group_first_block_no(sb, 973 EXT4_I(inode)->i_block_group); 974 975 /* non-extent files can't have physical blocks past 2^32 */ 976 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 977 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS; 978 979 block = ext4_new_meta_blocks(handle, inode, goal, 0, 980 NULL, &error); 981 if (error) 982 goto cleanup; 983 984 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 985 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS); 986 987 ea_idebug(inode, "creating block %llu", 988 (unsigned long long)block); 989 990 new_bh = sb_getblk(sb, block); 991 if (unlikely(!new_bh)) { 992 error = -ENOMEM; 993 getblk_failed: 994 ext4_free_blocks(handle, inode, NULL, block, 1, 995 EXT4_FREE_BLOCKS_METADATA); 996 goto cleanup; 997 } 998 lock_buffer(new_bh); 999 error = ext4_journal_get_create_access(handle, new_bh); 1000 if (error) { 1001 unlock_buffer(new_bh); 1002 error = -EIO; 1003 goto getblk_failed; 1004 } 1005 memcpy(new_bh->b_data, s->base, new_bh->b_size); 1006 set_buffer_uptodate(new_bh); 1007 unlock_buffer(new_bh); 1008 ext4_xattr_cache_insert(ext4_mb_cache, new_bh); 1009 error = ext4_handle_dirty_xattr_block(handle, 1010 inode, new_bh); 1011 if (error) 1012 goto cleanup; 1013 } 1014 } 1015 1016 /* Update the inode. */ 1017 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; 1018 1019 /* Drop the previous xattr block. */ 1020 if (bs->bh && bs->bh != new_bh) 1021 ext4_xattr_release_block(handle, inode, bs->bh); 1022 error = 0; 1023 1024 cleanup: 1025 if (ce) 1026 mb_cache_entry_put(ext4_mb_cache, ce); 1027 brelse(new_bh); 1028 if (!(bs->bh && s->base == bs->bh->b_data)) 1029 kfree(s->base); 1030 1031 return error; 1032 1033 cleanup_dquot: 1034 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1)); 1035 goto cleanup; 1036 1037 bad_block: 1038 EXT4_ERROR_INODE(inode, "bad block %llu", 1039 EXT4_I(inode)->i_file_acl); 1040 goto cleanup; 1041 1042 #undef header 1043 } 1044 1045 int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, 1046 struct ext4_xattr_ibody_find *is) 1047 { 1048 struct ext4_xattr_ibody_header *header; 1049 struct ext4_inode *raw_inode; 1050 int error; 1051 1052 if (EXT4_I(inode)->i_extra_isize == 0) 1053 return 0; 1054 raw_inode = ext4_raw_inode(&is->iloc); 1055 header = IHDR(inode, raw_inode); 1056 is->s.base = is->s.first = IFIRST(header); 1057 is->s.here = is->s.first; 1058 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 1059 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { 1060 error = xattr_check_inode(inode, header, is->s.end); 1061 if (error) 1062 return error; 1063 /* Find the named attribute. */ 1064 error = ext4_xattr_find_entry(&is->s.here, i->name_index, 1065 i->name, is->s.end - 1066 (void *)is->s.base, 0); 1067 if (error && error != -ENODATA) 1068 return error; 1069 is->s.not_found = error; 1070 } 1071 return 0; 1072 } 1073 1074 int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode, 1075 struct ext4_xattr_info *i, 1076 struct ext4_xattr_ibody_find *is) 1077 { 1078 struct ext4_xattr_ibody_header *header; 1079 struct ext4_xattr_search *s = &is->s; 1080 int error; 1081 1082 if (EXT4_I(inode)->i_extra_isize == 0) 1083 return -ENOSPC; 1084 error = ext4_xattr_set_entry(i, s); 1085 if (error) { 1086 if (error == -ENOSPC && 1087 ext4_has_inline_data(inode)) { 1088 error = ext4_try_to_evict_inline_data(handle, inode, 1089 EXT4_XATTR_LEN(strlen(i->name) + 1090 EXT4_XATTR_SIZE(i->value_len))); 1091 if (error) 1092 return error; 1093 error = ext4_xattr_ibody_find(inode, i, is); 1094 if (error) 1095 return error; 1096 error = ext4_xattr_set_entry(i, s); 1097 } 1098 if (error) 1099 return error; 1100 } 1101 header = IHDR(inode, ext4_raw_inode(&is->iloc)); 1102 if (!IS_LAST_ENTRY(s->first)) { 1103 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 1104 ext4_set_inode_state(inode, EXT4_STATE_XATTR); 1105 } else { 1106 header->h_magic = cpu_to_le32(0); 1107 ext4_clear_inode_state(inode, EXT4_STATE_XATTR); 1108 } 1109 return 0; 1110 } 1111 1112 static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode, 1113 struct ext4_xattr_info *i, 1114 struct ext4_xattr_ibody_find *is) 1115 { 1116 struct ext4_xattr_ibody_header *header; 1117 struct ext4_xattr_search *s = &is->s; 1118 int error; 1119 1120 if (EXT4_I(inode)->i_extra_isize == 0) 1121 return -ENOSPC; 1122 error = ext4_xattr_set_entry(i, s); 1123 if (error) 1124 return error; 1125 header = IHDR(inode, ext4_raw_inode(&is->iloc)); 1126 if (!IS_LAST_ENTRY(s->first)) { 1127 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 1128 ext4_set_inode_state(inode, EXT4_STATE_XATTR); 1129 } else { 1130 header->h_magic = cpu_to_le32(0); 1131 ext4_clear_inode_state(inode, EXT4_STATE_XATTR); 1132 } 1133 return 0; 1134 } 1135 1136 static int ext4_xattr_value_same(struct ext4_xattr_search *s, 1137 struct ext4_xattr_info *i) 1138 { 1139 void *value; 1140 1141 if (le32_to_cpu(s->here->e_value_size) != i->value_len) 1142 return 0; 1143 value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs); 1144 return !memcmp(value, i->value, i->value_len); 1145 } 1146 1147 /* 1148 * ext4_xattr_set_handle() 1149 * 1150 * Create, replace or remove an extended attribute for this inode. Value 1151 * is NULL to remove an existing extended attribute, and non-NULL to 1152 * either replace an existing extended attribute, or create a new extended 1153 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 1154 * specify that an extended attribute must exist and must not exist 1155 * previous to the call, respectively. 1156 * 1157 * Returns 0, or a negative error number on failure. 1158 */ 1159 int 1160 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, 1161 const char *name, const void *value, size_t value_len, 1162 int flags) 1163 { 1164 struct ext4_xattr_info i = { 1165 .name_index = name_index, 1166 .name = name, 1167 .value = value, 1168 .value_len = value_len, 1169 1170 }; 1171 struct ext4_xattr_ibody_find is = { 1172 .s = { .not_found = -ENODATA, }, 1173 }; 1174 struct ext4_xattr_block_find bs = { 1175 .s = { .not_found = -ENODATA, }, 1176 }; 1177 unsigned long no_expand; 1178 int error; 1179 1180 if (!name) 1181 return -EINVAL; 1182 if (strlen(name) > 255) 1183 return -ERANGE; 1184 down_write(&EXT4_I(inode)->xattr_sem); 1185 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND); 1186 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); 1187 1188 error = ext4_reserve_inode_write(handle, inode, &is.iloc); 1189 if (error) 1190 goto cleanup; 1191 1192 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) { 1193 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc); 1194 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); 1195 ext4_clear_inode_state(inode, EXT4_STATE_NEW); 1196 } 1197 1198 error = ext4_xattr_ibody_find(inode, &i, &is); 1199 if (error) 1200 goto cleanup; 1201 if (is.s.not_found) 1202 error = ext4_xattr_block_find(inode, &i, &bs); 1203 if (error) 1204 goto cleanup; 1205 if (is.s.not_found && bs.s.not_found) { 1206 error = -ENODATA; 1207 if (flags & XATTR_REPLACE) 1208 goto cleanup; 1209 error = 0; 1210 if (!value) 1211 goto cleanup; 1212 } else { 1213 error = -EEXIST; 1214 if (flags & XATTR_CREATE) 1215 goto cleanup; 1216 } 1217 if (!value) { 1218 if (!is.s.not_found) 1219 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1220 else if (!bs.s.not_found) 1221 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1222 } else { 1223 error = 0; 1224 /* Xattr value did not change? Save us some work and bail out */ 1225 if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i)) 1226 goto cleanup; 1227 if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i)) 1228 goto cleanup; 1229 1230 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1231 if (!error && !bs.s.not_found) { 1232 i.value = NULL; 1233 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1234 } else if (error == -ENOSPC) { 1235 if (EXT4_I(inode)->i_file_acl && !bs.s.base) { 1236 error = ext4_xattr_block_find(inode, &i, &bs); 1237 if (error) 1238 goto cleanup; 1239 } 1240 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1241 if (error) 1242 goto cleanup; 1243 if (!is.s.not_found) { 1244 i.value = NULL; 1245 error = ext4_xattr_ibody_set(handle, inode, &i, 1246 &is); 1247 } 1248 } 1249 } 1250 if (!error) { 1251 ext4_xattr_update_super_block(handle, inode->i_sb); 1252 inode->i_ctime = ext4_current_time(inode); 1253 if (!value) 1254 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); 1255 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc); 1256 /* 1257 * The bh is consumed by ext4_mark_iloc_dirty, even with 1258 * error != 0. 1259 */ 1260 is.iloc.bh = NULL; 1261 if (IS_SYNC(inode)) 1262 ext4_handle_sync(handle); 1263 } 1264 1265 cleanup: 1266 brelse(is.iloc.bh); 1267 brelse(bs.bh); 1268 if (no_expand == 0) 1269 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); 1270 up_write(&EXT4_I(inode)->xattr_sem); 1271 return error; 1272 } 1273 1274 /* 1275 * ext4_xattr_set() 1276 * 1277 * Like ext4_xattr_set_handle, but start from an inode. This extended 1278 * attribute modification is a filesystem transaction by itself. 1279 * 1280 * Returns 0, or a negative error number on failure. 1281 */ 1282 int 1283 ext4_xattr_set(struct inode *inode, int name_index, const char *name, 1284 const void *value, size_t value_len, int flags) 1285 { 1286 handle_t *handle; 1287 int error, retries = 0; 1288 int credits = ext4_jbd2_credits_xattr(inode); 1289 1290 retry: 1291 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits); 1292 if (IS_ERR(handle)) { 1293 error = PTR_ERR(handle); 1294 } else { 1295 int error2; 1296 1297 error = ext4_xattr_set_handle(handle, inode, name_index, name, 1298 value, value_len, flags); 1299 error2 = ext4_journal_stop(handle); 1300 if (error == -ENOSPC && 1301 ext4_should_retry_alloc(inode->i_sb, &retries)) 1302 goto retry; 1303 if (error == 0) 1304 error = error2; 1305 } 1306 1307 return error; 1308 } 1309 1310 /* 1311 * Shift the EA entries in the inode to create space for the increased 1312 * i_extra_isize. 1313 */ 1314 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry, 1315 int value_offs_shift, void *to, 1316 void *from, size_t n) 1317 { 1318 struct ext4_xattr_entry *last = entry; 1319 int new_offs; 1320 1321 /* We always shift xattr headers further thus offsets get lower */ 1322 BUG_ON(value_offs_shift > 0); 1323 1324 /* Adjust the value offsets of the entries */ 1325 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1326 if (last->e_value_size) { 1327 new_offs = le16_to_cpu(last->e_value_offs) + 1328 value_offs_shift; 1329 last->e_value_offs = cpu_to_le16(new_offs); 1330 } 1331 } 1332 /* Shift the entries by n bytes */ 1333 memmove(to, from, n); 1334 } 1335 1336 /* 1337 * Move xattr pointed to by 'entry' from inode into external xattr block 1338 */ 1339 static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode, 1340 struct ext4_inode *raw_inode, 1341 struct ext4_xattr_entry *entry) 1342 { 1343 struct ext4_xattr_ibody_find *is = NULL; 1344 struct ext4_xattr_block_find *bs = NULL; 1345 char *buffer = NULL, *b_entry_name = NULL; 1346 size_t value_offs, value_size; 1347 struct ext4_xattr_info i = { 1348 .value = NULL, 1349 .value_len = 0, 1350 .name_index = entry->e_name_index, 1351 }; 1352 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode); 1353 int error; 1354 1355 value_offs = le16_to_cpu(entry->e_value_offs); 1356 value_size = le32_to_cpu(entry->e_value_size); 1357 1358 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS); 1359 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS); 1360 buffer = kmalloc(value_size, GFP_NOFS); 1361 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS); 1362 if (!is || !bs || !buffer || !b_entry_name) { 1363 error = -ENOMEM; 1364 goto out; 1365 } 1366 1367 is->s.not_found = -ENODATA; 1368 bs->s.not_found = -ENODATA; 1369 is->iloc.bh = NULL; 1370 bs->bh = NULL; 1371 1372 /* Save the entry name and the entry value */ 1373 memcpy(buffer, (void *)IFIRST(header) + value_offs, value_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 out; 1381 1382 error = ext4_xattr_ibody_find(inode, &i, is); 1383 if (error) 1384 goto out; 1385 1386 /* Remove the chosen entry from the inode */ 1387 error = ext4_xattr_ibody_set(handle, inode, &i, is); 1388 if (error) 1389 goto out; 1390 1391 i.name = b_entry_name; 1392 i.value = buffer; 1393 i.value_len = value_size; 1394 error = ext4_xattr_block_find(inode, &i, bs); 1395 if (error) 1396 goto out; 1397 1398 /* Add entry which was removed from the inode into the block */ 1399 error = ext4_xattr_block_set(handle, inode, &i, bs); 1400 if (error) 1401 goto out; 1402 error = 0; 1403 out: 1404 kfree(b_entry_name); 1405 kfree(buffer); 1406 if (is) 1407 brelse(is->iloc.bh); 1408 kfree(is); 1409 kfree(bs); 1410 1411 return error; 1412 } 1413 1414 static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode, 1415 struct ext4_inode *raw_inode, 1416 int isize_diff, size_t ifree, 1417 size_t bfree, int *total_ino) 1418 { 1419 struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode); 1420 struct ext4_xattr_entry *small_entry; 1421 struct ext4_xattr_entry *entry; 1422 struct ext4_xattr_entry *last; 1423 unsigned int entry_size; /* EA entry size */ 1424 unsigned int total_size; /* EA entry size + value size */ 1425 unsigned int min_total_size; 1426 int error; 1427 1428 while (isize_diff > ifree) { 1429 entry = NULL; 1430 small_entry = NULL; 1431 min_total_size = ~0U; 1432 last = IFIRST(header); 1433 /* Find the entry best suited to be pushed into EA block */ 1434 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1435 total_size = 1436 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) + 1437 EXT4_XATTR_LEN(last->e_name_len); 1438 if (total_size <= bfree && 1439 total_size < min_total_size) { 1440 if (total_size + ifree < isize_diff) { 1441 small_entry = last; 1442 } else { 1443 entry = last; 1444 min_total_size = total_size; 1445 } 1446 } 1447 } 1448 1449 if (entry == NULL) { 1450 if (small_entry == NULL) 1451 return -ENOSPC; 1452 entry = small_entry; 1453 } 1454 1455 entry_size = EXT4_XATTR_LEN(entry->e_name_len); 1456 total_size = entry_size + 1457 EXT4_XATTR_SIZE(le32_to_cpu(entry->e_value_size)); 1458 error = ext4_xattr_move_to_block(handle, inode, raw_inode, 1459 entry); 1460 if (error) 1461 return error; 1462 1463 *total_ino -= entry_size; 1464 ifree += total_size; 1465 bfree -= total_size; 1466 } 1467 1468 return 0; 1469 } 1470 1471 /* 1472 * Expand an inode by new_extra_isize bytes when EAs are present. 1473 * Returns 0 on success or negative error number on failure. 1474 */ 1475 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, 1476 struct ext4_inode *raw_inode, handle_t *handle) 1477 { 1478 struct ext4_xattr_ibody_header *header; 1479 struct buffer_head *bh = NULL; 1480 size_t min_offs; 1481 size_t ifree, bfree; 1482 int total_ino; 1483 void *base, *end; 1484 int error = 0, tried_min_extra_isize = 0; 1485 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize); 1486 int isize_diff; /* How much do we need to grow i_extra_isize */ 1487 1488 down_write(&EXT4_I(inode)->xattr_sem); 1489 /* 1490 * Set EXT4_STATE_NO_EXPAND to avoid recursion when marking inode dirty 1491 */ 1492 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); 1493 retry: 1494 isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize; 1495 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) 1496 goto out; 1497 1498 header = IHDR(inode, raw_inode); 1499 1500 /* 1501 * Check if enough free space is available in the inode to shift the 1502 * entries ahead by new_extra_isize. 1503 */ 1504 1505 base = IFIRST(header); 1506 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 1507 min_offs = end - base; 1508 total_ino = sizeof(struct ext4_xattr_ibody_header); 1509 1510 error = xattr_check_inode(inode, header, end); 1511 if (error) 1512 goto cleanup; 1513 1514 ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino); 1515 if (ifree >= isize_diff) 1516 goto shift; 1517 1518 /* 1519 * Enough free space isn't available in the inode, check if 1520 * EA block can hold new_extra_isize bytes. 1521 */ 1522 if (EXT4_I(inode)->i_file_acl) { 1523 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1524 error = -EIO; 1525 if (!bh) 1526 goto cleanup; 1527 if (ext4_xattr_check_block(inode, bh)) { 1528 EXT4_ERROR_INODE(inode, "bad block %llu", 1529 EXT4_I(inode)->i_file_acl); 1530 error = -EFSCORRUPTED; 1531 goto cleanup; 1532 } 1533 base = BHDR(bh); 1534 end = bh->b_data + bh->b_size; 1535 min_offs = end - base; 1536 bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base, 1537 NULL); 1538 if (bfree + ifree < isize_diff) { 1539 if (!tried_min_extra_isize && s_min_extra_isize) { 1540 tried_min_extra_isize++; 1541 new_extra_isize = s_min_extra_isize; 1542 brelse(bh); 1543 goto retry; 1544 } 1545 error = -ENOSPC; 1546 goto cleanup; 1547 } 1548 } else { 1549 bfree = inode->i_sb->s_blocksize; 1550 } 1551 1552 error = ext4_xattr_make_inode_space(handle, inode, raw_inode, 1553 isize_diff, ifree, bfree, 1554 &total_ino); 1555 if (error) { 1556 if (error == -ENOSPC && !tried_min_extra_isize && 1557 s_min_extra_isize) { 1558 tried_min_extra_isize++; 1559 new_extra_isize = s_min_extra_isize; 1560 brelse(bh); 1561 goto retry; 1562 } 1563 goto cleanup; 1564 } 1565 shift: 1566 /* Adjust the offsets and shift the remaining entries ahead */ 1567 ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize 1568 - new_extra_isize, (void *)raw_inode + 1569 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize, 1570 (void *)header, total_ino); 1571 EXT4_I(inode)->i_extra_isize = new_extra_isize; 1572 brelse(bh); 1573 out: 1574 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); 1575 up_write(&EXT4_I(inode)->xattr_sem); 1576 return 0; 1577 1578 cleanup: 1579 brelse(bh); 1580 /* 1581 * We deliberately leave EXT4_STATE_NO_EXPAND set here since inode 1582 * size expansion failed. 1583 */ 1584 up_write(&EXT4_I(inode)->xattr_sem); 1585 return error; 1586 } 1587 1588 1589 1590 /* 1591 * ext4_xattr_delete_inode() 1592 * 1593 * Free extended attribute resources associated with this inode. This 1594 * is called immediately before an inode is freed. We have exclusive 1595 * access to the inode. 1596 */ 1597 void 1598 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode) 1599 { 1600 struct buffer_head *bh = NULL; 1601 1602 if (!EXT4_I(inode)->i_file_acl) 1603 goto cleanup; 1604 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1605 if (!bh) { 1606 EXT4_ERROR_INODE(inode, "block %llu read error", 1607 EXT4_I(inode)->i_file_acl); 1608 goto cleanup; 1609 } 1610 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 1611 BHDR(bh)->h_blocks != cpu_to_le32(1)) { 1612 EXT4_ERROR_INODE(inode, "bad block %llu", 1613 EXT4_I(inode)->i_file_acl); 1614 goto cleanup; 1615 } 1616 ext4_xattr_release_block(handle, inode, bh); 1617 EXT4_I(inode)->i_file_acl = 0; 1618 1619 cleanup: 1620 brelse(bh); 1621 } 1622 1623 /* 1624 * ext4_xattr_cache_insert() 1625 * 1626 * Create a new entry in the extended attribute cache, and insert 1627 * it unless such an entry is already in the cache. 1628 * 1629 * Returns 0, or a negative error number on failure. 1630 */ 1631 static void 1632 ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh) 1633 { 1634 struct ext4_xattr_header *header = BHDR(bh); 1635 __u32 hash = le32_to_cpu(header->h_hash); 1636 int reusable = le32_to_cpu(header->h_refcount) < 1637 EXT4_XATTR_REFCOUNT_MAX; 1638 int error; 1639 1640 error = mb_cache_entry_create(ext4_mb_cache, GFP_NOFS, hash, 1641 bh->b_blocknr, reusable); 1642 if (error) { 1643 if (error == -EBUSY) 1644 ea_bdebug(bh, "already in cache"); 1645 } else 1646 ea_bdebug(bh, "inserting [%x]", (int)hash); 1647 } 1648 1649 /* 1650 * ext4_xattr_cmp() 1651 * 1652 * Compare two extended attribute blocks for equality. 1653 * 1654 * Returns 0 if the blocks are equal, 1 if they differ, and 1655 * a negative error number on errors. 1656 */ 1657 static int 1658 ext4_xattr_cmp(struct ext4_xattr_header *header1, 1659 struct ext4_xattr_header *header2) 1660 { 1661 struct ext4_xattr_entry *entry1, *entry2; 1662 1663 entry1 = ENTRY(header1+1); 1664 entry2 = ENTRY(header2+1); 1665 while (!IS_LAST_ENTRY(entry1)) { 1666 if (IS_LAST_ENTRY(entry2)) 1667 return 1; 1668 if (entry1->e_hash != entry2->e_hash || 1669 entry1->e_name_index != entry2->e_name_index || 1670 entry1->e_name_len != entry2->e_name_len || 1671 entry1->e_value_size != entry2->e_value_size || 1672 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) 1673 return 1; 1674 if (entry1->e_value_block != 0 || entry2->e_value_block != 0) 1675 return -EFSCORRUPTED; 1676 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), 1677 (char *)header2 + le16_to_cpu(entry2->e_value_offs), 1678 le32_to_cpu(entry1->e_value_size))) 1679 return 1; 1680 1681 entry1 = EXT4_XATTR_NEXT(entry1); 1682 entry2 = EXT4_XATTR_NEXT(entry2); 1683 } 1684 if (!IS_LAST_ENTRY(entry2)) 1685 return 1; 1686 return 0; 1687 } 1688 1689 /* 1690 * ext4_xattr_cache_find() 1691 * 1692 * Find an identical extended attribute block. 1693 * 1694 * Returns a pointer to the block found, or NULL if such a block was 1695 * not found or an error occurred. 1696 */ 1697 static struct buffer_head * 1698 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header, 1699 struct mb_cache_entry **pce) 1700 { 1701 __u32 hash = le32_to_cpu(header->h_hash); 1702 struct mb_cache_entry *ce; 1703 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 1704 1705 if (!header->h_hash) 1706 return NULL; /* never share */ 1707 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); 1708 ce = mb_cache_entry_find_first(ext4_mb_cache, hash); 1709 while (ce) { 1710 struct buffer_head *bh; 1711 1712 bh = sb_bread(inode->i_sb, ce->e_block); 1713 if (!bh) { 1714 EXT4_ERROR_INODE(inode, "block %lu read error", 1715 (unsigned long) ce->e_block); 1716 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) { 1717 *pce = ce; 1718 return bh; 1719 } 1720 brelse(bh); 1721 ce = mb_cache_entry_find_next(ext4_mb_cache, ce); 1722 } 1723 return NULL; 1724 } 1725 1726 #define NAME_HASH_SHIFT 5 1727 #define VALUE_HASH_SHIFT 16 1728 1729 /* 1730 * ext4_xattr_hash_entry() 1731 * 1732 * Compute the hash of an extended attribute. 1733 */ 1734 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header, 1735 struct ext4_xattr_entry *entry) 1736 { 1737 __u32 hash = 0; 1738 char *name = entry->e_name; 1739 int n; 1740 1741 for (n = 0; n < entry->e_name_len; n++) { 1742 hash = (hash << NAME_HASH_SHIFT) ^ 1743 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ 1744 *name++; 1745 } 1746 1747 if (entry->e_value_size != 0) { 1748 __le32 *value = (__le32 *)((char *)header + 1749 le16_to_cpu(entry->e_value_offs)); 1750 for (n = (le32_to_cpu(entry->e_value_size) + 1751 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) { 1752 hash = (hash << VALUE_HASH_SHIFT) ^ 1753 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ 1754 le32_to_cpu(*value++); 1755 } 1756 } 1757 entry->e_hash = cpu_to_le32(hash); 1758 } 1759 1760 #undef NAME_HASH_SHIFT 1761 #undef VALUE_HASH_SHIFT 1762 1763 #define BLOCK_HASH_SHIFT 16 1764 1765 /* 1766 * ext4_xattr_rehash() 1767 * 1768 * Re-compute the extended attribute hash value after an entry has changed. 1769 */ 1770 static void ext4_xattr_rehash(struct ext4_xattr_header *header, 1771 struct ext4_xattr_entry *entry) 1772 { 1773 struct ext4_xattr_entry *here; 1774 __u32 hash = 0; 1775 1776 ext4_xattr_hash_entry(header, entry); 1777 here = ENTRY(header+1); 1778 while (!IS_LAST_ENTRY(here)) { 1779 if (!here->e_hash) { 1780 /* Block is not shared if an entry's hash value == 0 */ 1781 hash = 0; 1782 break; 1783 } 1784 hash = (hash << BLOCK_HASH_SHIFT) ^ 1785 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ 1786 le32_to_cpu(here->e_hash); 1787 here = EXT4_XATTR_NEXT(here); 1788 } 1789 header->h_hash = cpu_to_le32(hash); 1790 } 1791 1792 #undef BLOCK_HASH_SHIFT 1793 1794 #define HASH_BUCKET_BITS 10 1795 1796 struct mb_cache * 1797 ext4_xattr_create_cache(void) 1798 { 1799 return mb_cache_create(HASH_BUCKET_BITS); 1800 } 1801 1802 void ext4_xattr_destroy_cache(struct mb_cache *cache) 1803 { 1804 if (cache) 1805 mb_cache_destroy(cache); 1806 } 1807 1808