1 /* 2 * linux/fs/ext4/xattr.c 3 * 4 * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de> 5 * 6 * Fix by Harrison Xing <harrison@mountainviewdata.com>. 7 * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>. 8 * Extended attributes for symlinks and special files added per 9 * suggestion of Luka Renko <luka.renko@hermes.si>. 10 * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>, 11 * Red Hat Inc. 12 * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz 13 * and Andreas Gruenbacher <agruen@suse.de>. 14 */ 15 16 /* 17 * Extended attributes are stored directly in inodes (on file systems with 18 * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl 19 * field contains the block number if an inode uses an additional block. All 20 * attributes must fit in the inode and one additional block. Blocks that 21 * contain the identical set of attributes may be shared among several inodes. 22 * Identical blocks are detected by keeping a cache of blocks that have 23 * recently been accessed. 24 * 25 * The attributes in inodes and on blocks have a different header; the entries 26 * are stored in the same format: 27 * 28 * +------------------+ 29 * | header | 30 * | entry 1 | | 31 * | entry 2 | | growing downwards 32 * | entry 3 | v 33 * | four null bytes | 34 * | . . . | 35 * | value 1 | ^ 36 * | value 3 | | growing upwards 37 * | value 2 | | 38 * +------------------+ 39 * 40 * The header is followed by multiple entry descriptors. In disk blocks, the 41 * entry descriptors are kept sorted. In inodes, they are unsorted. The 42 * attribute values are aligned to the end of the block in no specific order. 43 * 44 * Locking strategy 45 * ---------------- 46 * EXT4_I(inode)->i_file_acl is protected by EXT4_I(inode)->xattr_sem. 47 * EA blocks are only changed if they are exclusive to an inode, so 48 * holding xattr_sem also means that nothing but the EA block's reference 49 * count can change. Multiple writers to the same block are synchronized 50 * by the buffer lock. 51 */ 52 53 #include <linux/init.h> 54 #include <linux/fs.h> 55 #include <linux/slab.h> 56 #include <linux/mbcache.h> 57 #include <linux/quotaops.h> 58 #include <linux/rwsem.h> 59 #include "ext4_jbd2.h" 60 #include "ext4.h" 61 #include "xattr.h" 62 #include "acl.h" 63 64 #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data)) 65 #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr)) 66 #define BFIRST(bh) ENTRY(BHDR(bh)+1) 67 #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0) 68 69 #ifdef EXT4_XATTR_DEBUG 70 # define ea_idebug(inode, f...) do { \ 71 printk(KERN_DEBUG "inode %s:%lu: ", \ 72 inode->i_sb->s_id, inode->i_ino); \ 73 printk(f); \ 74 printk("\n"); \ 75 } while (0) 76 # define ea_bdebug(bh, f...) do { \ 77 char b[BDEVNAME_SIZE]; \ 78 printk(KERN_DEBUG "block %s:%lu: ", \ 79 bdevname(bh->b_bdev, b), \ 80 (unsigned long) bh->b_blocknr); \ 81 printk(f); \ 82 printk("\n"); \ 83 } while (0) 84 #else 85 # define ea_idebug(f...) 86 # define ea_bdebug(f...) 87 #endif 88 89 static void ext4_xattr_cache_insert(struct buffer_head *); 90 static struct buffer_head *ext4_xattr_cache_find(struct inode *, 91 struct ext4_xattr_header *, 92 struct mb_cache_entry **); 93 static void ext4_xattr_rehash(struct ext4_xattr_header *, 94 struct ext4_xattr_entry *); 95 static int ext4_xattr_list(struct dentry *dentry, char *buffer, 96 size_t buffer_size); 97 98 static struct mb_cache *ext4_xattr_cache; 99 100 static struct xattr_handler *ext4_xattr_handler_map[] = { 101 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler, 102 #ifdef CONFIG_EXT4_FS_POSIX_ACL 103 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler, 104 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler, 105 #endif 106 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler, 107 #ifdef CONFIG_EXT4_FS_SECURITY 108 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler, 109 #endif 110 }; 111 112 struct xattr_handler *ext4_xattr_handlers[] = { 113 &ext4_xattr_user_handler, 114 &ext4_xattr_trusted_handler, 115 #ifdef CONFIG_EXT4_FS_POSIX_ACL 116 &ext4_xattr_acl_access_handler, 117 &ext4_xattr_acl_default_handler, 118 #endif 119 #ifdef CONFIG_EXT4_FS_SECURITY 120 &ext4_xattr_security_handler, 121 #endif 122 NULL 123 }; 124 125 static inline struct xattr_handler * 126 ext4_xattr_handler(int name_index) 127 { 128 struct xattr_handler *handler = NULL; 129 130 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map)) 131 handler = ext4_xattr_handler_map[name_index]; 132 return handler; 133 } 134 135 /* 136 * Inode operation listxattr() 137 * 138 * dentry->d_inode->i_mutex: don't care 139 */ 140 ssize_t 141 ext4_listxattr(struct dentry *dentry, char *buffer, size_t size) 142 { 143 return ext4_xattr_list(dentry, buffer, size); 144 } 145 146 static int 147 ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end) 148 { 149 while (!IS_LAST_ENTRY(entry)) { 150 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry); 151 if ((void *)next >= end) 152 return -EIO; 153 entry = next; 154 } 155 return 0; 156 } 157 158 static inline int 159 ext4_xattr_check_block(struct buffer_head *bh) 160 { 161 int error; 162 163 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 164 BHDR(bh)->h_blocks != cpu_to_le32(1)) 165 return -EIO; 166 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size); 167 return error; 168 } 169 170 static inline int 171 ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size) 172 { 173 size_t value_size = le32_to_cpu(entry->e_value_size); 174 175 if (entry->e_value_block != 0 || value_size > size || 176 le16_to_cpu(entry->e_value_offs) + value_size > size) 177 return -EIO; 178 return 0; 179 } 180 181 static int 182 ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index, 183 const char *name, size_t size, int sorted) 184 { 185 struct ext4_xattr_entry *entry; 186 size_t name_len; 187 int cmp = 1; 188 189 if (name == NULL) 190 return -EINVAL; 191 name_len = strlen(name); 192 entry = *pentry; 193 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 194 cmp = name_index - entry->e_name_index; 195 if (!cmp) 196 cmp = name_len - entry->e_name_len; 197 if (!cmp) 198 cmp = memcmp(name, entry->e_name, name_len); 199 if (cmp <= 0 && (sorted || cmp == 0)) 200 break; 201 } 202 *pentry = entry; 203 if (!cmp && ext4_xattr_check_entry(entry, size)) 204 return -EIO; 205 return cmp ? -ENODATA : 0; 206 } 207 208 static int 209 ext4_xattr_block_get(struct inode *inode, int name_index, const char *name, 210 void *buffer, size_t buffer_size) 211 { 212 struct buffer_head *bh = NULL; 213 struct ext4_xattr_entry *entry; 214 size_t size; 215 int error; 216 217 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", 218 name_index, name, buffer, (long)buffer_size); 219 220 error = -ENODATA; 221 if (!EXT4_I(inode)->i_file_acl) 222 goto cleanup; 223 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl); 224 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 225 if (!bh) 226 goto cleanup; 227 ea_bdebug(bh, "b_count=%d, refcount=%d", 228 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 229 if (ext4_xattr_check_block(bh)) { 230 bad_block: ext4_error(inode->i_sb, __func__, 231 "inode %lu: bad block %llu", inode->i_ino, 232 EXT4_I(inode)->i_file_acl); 233 error = -EIO; 234 goto cleanup; 235 } 236 ext4_xattr_cache_insert(bh); 237 entry = BFIRST(bh); 238 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1); 239 if (error == -EIO) 240 goto bad_block; 241 if (error) 242 goto cleanup; 243 size = le32_to_cpu(entry->e_value_size); 244 if (buffer) { 245 error = -ERANGE; 246 if (size > buffer_size) 247 goto cleanup; 248 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), 249 size); 250 } 251 error = size; 252 253 cleanup: 254 brelse(bh); 255 return error; 256 } 257 258 static int 259 ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name, 260 void *buffer, size_t buffer_size) 261 { 262 struct ext4_xattr_ibody_header *header; 263 struct ext4_xattr_entry *entry; 264 struct ext4_inode *raw_inode; 265 struct ext4_iloc iloc; 266 size_t size; 267 void *end; 268 int error; 269 270 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR)) 271 return -ENODATA; 272 error = ext4_get_inode_loc(inode, &iloc); 273 if (error) 274 return error; 275 raw_inode = ext4_raw_inode(&iloc); 276 header = IHDR(inode, raw_inode); 277 entry = IFIRST(header); 278 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 279 error = ext4_xattr_check_names(entry, end); 280 if (error) 281 goto cleanup; 282 error = ext4_xattr_find_entry(&entry, name_index, name, 283 end - (void *)entry, 0); 284 if (error) 285 goto cleanup; 286 size = le32_to_cpu(entry->e_value_size); 287 if (buffer) { 288 error = -ERANGE; 289 if (size > buffer_size) 290 goto cleanup; 291 memcpy(buffer, (void *)IFIRST(header) + 292 le16_to_cpu(entry->e_value_offs), size); 293 } 294 error = size; 295 296 cleanup: 297 brelse(iloc.bh); 298 return error; 299 } 300 301 /* 302 * ext4_xattr_get() 303 * 304 * Copy an extended attribute into the buffer 305 * provided, or compute the buffer size required. 306 * Buffer is NULL to compute the size of the buffer required. 307 * 308 * Returns a negative error number on failure, or the number of bytes 309 * used / required on success. 310 */ 311 int 312 ext4_xattr_get(struct inode *inode, int name_index, const char *name, 313 void *buffer, size_t buffer_size) 314 { 315 int error; 316 317 down_read(&EXT4_I(inode)->xattr_sem); 318 error = ext4_xattr_ibody_get(inode, name_index, name, buffer, 319 buffer_size); 320 if (error == -ENODATA) 321 error = ext4_xattr_block_get(inode, name_index, name, buffer, 322 buffer_size); 323 up_read(&EXT4_I(inode)->xattr_sem); 324 return error; 325 } 326 327 static int 328 ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry, 329 char *buffer, size_t buffer_size) 330 { 331 size_t rest = buffer_size; 332 333 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 334 struct xattr_handler *handler = 335 ext4_xattr_handler(entry->e_name_index); 336 337 if (handler) { 338 size_t size = handler->list(dentry, buffer, rest, 339 entry->e_name, 340 entry->e_name_len, 341 handler->flags); 342 if (buffer) { 343 if (size > rest) 344 return -ERANGE; 345 buffer += size; 346 } 347 rest -= size; 348 } 349 } 350 return buffer_size - rest; 351 } 352 353 static int 354 ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size) 355 { 356 struct inode *inode = dentry->d_inode; 357 struct buffer_head *bh = NULL; 358 int error; 359 360 ea_idebug(inode, "buffer=%p, buffer_size=%ld", 361 buffer, (long)buffer_size); 362 363 error = 0; 364 if (!EXT4_I(inode)->i_file_acl) 365 goto cleanup; 366 ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl); 367 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 368 error = -EIO; 369 if (!bh) 370 goto cleanup; 371 ea_bdebug(bh, "b_count=%d, refcount=%d", 372 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 373 if (ext4_xattr_check_block(bh)) { 374 ext4_error(inode->i_sb, __func__, 375 "inode %lu: bad block %llu", inode->i_ino, 376 EXT4_I(inode)->i_file_acl); 377 error = -EIO; 378 goto cleanup; 379 } 380 ext4_xattr_cache_insert(bh); 381 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size); 382 383 cleanup: 384 brelse(bh); 385 386 return error; 387 } 388 389 static int 390 ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size) 391 { 392 struct inode *inode = dentry->d_inode; 393 struct ext4_xattr_ibody_header *header; 394 struct ext4_inode *raw_inode; 395 struct ext4_iloc iloc; 396 void *end; 397 int error; 398 399 if (!(EXT4_I(inode)->i_state & EXT4_STATE_XATTR)) 400 return 0; 401 error = ext4_get_inode_loc(inode, &iloc); 402 if (error) 403 return error; 404 raw_inode = ext4_raw_inode(&iloc); 405 header = IHDR(inode, raw_inode); 406 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 407 error = ext4_xattr_check_names(IFIRST(header), end); 408 if (error) 409 goto cleanup; 410 error = ext4_xattr_list_entries(dentry, IFIRST(header), 411 buffer, buffer_size); 412 413 cleanup: 414 brelse(iloc.bh); 415 return error; 416 } 417 418 /* 419 * ext4_xattr_list() 420 * 421 * Copy a list of attribute names into the buffer 422 * provided, or compute the buffer size required. 423 * Buffer is NULL to compute the size of the buffer required. 424 * 425 * Returns a negative error number on failure, or the number of bytes 426 * used / required on success. 427 */ 428 static int 429 ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size) 430 { 431 int i_error, b_error; 432 433 down_read(&EXT4_I(dentry->d_inode)->xattr_sem); 434 i_error = ext4_xattr_ibody_list(dentry, buffer, buffer_size); 435 if (i_error < 0) { 436 b_error = 0; 437 } else { 438 if (buffer) { 439 buffer += i_error; 440 buffer_size -= i_error; 441 } 442 b_error = ext4_xattr_block_list(dentry, buffer, buffer_size); 443 if (b_error < 0) 444 i_error = 0; 445 } 446 up_read(&EXT4_I(dentry->d_inode)->xattr_sem); 447 return i_error + b_error; 448 } 449 450 /* 451 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is 452 * not set, set it. 453 */ 454 static void ext4_xattr_update_super_block(handle_t *handle, 455 struct super_block *sb) 456 { 457 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR)) 458 return; 459 460 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) { 461 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR); 462 sb->s_dirt = 1; 463 ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh); 464 } 465 } 466 467 /* 468 * Release the xattr block BH: If the reference count is > 1, decrement 469 * it; otherwise free the block. 470 */ 471 static void 472 ext4_xattr_release_block(handle_t *handle, struct inode *inode, 473 struct buffer_head *bh) 474 { 475 struct mb_cache_entry *ce = NULL; 476 int error = 0; 477 478 ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr); 479 error = ext4_journal_get_write_access(handle, bh); 480 if (error) 481 goto out; 482 483 lock_buffer(bh); 484 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) { 485 ea_bdebug(bh, "refcount now=0; freeing"); 486 if (ce) 487 mb_cache_entry_free(ce); 488 get_bh(bh); 489 ext4_free_blocks(handle, inode, bh, 0, 1, 490 EXT4_FREE_BLOCKS_METADATA | 491 EXT4_FREE_BLOCKS_FORGET); 492 } else { 493 le32_add_cpu(&BHDR(bh)->h_refcount, -1); 494 error = ext4_handle_dirty_metadata(handle, inode, bh); 495 if (IS_SYNC(inode)) 496 ext4_handle_sync(handle); 497 vfs_dq_free_block(inode, 1); 498 ea_bdebug(bh, "refcount now=%d; releasing", 499 le32_to_cpu(BHDR(bh)->h_refcount)); 500 if (ce) 501 mb_cache_entry_release(ce); 502 } 503 unlock_buffer(bh); 504 out: 505 ext4_std_error(inode->i_sb, error); 506 return; 507 } 508 509 /* 510 * Find the available free space for EAs. This also returns the total number of 511 * bytes used by EA entries. 512 */ 513 static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last, 514 size_t *min_offs, void *base, int *total) 515 { 516 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 517 *total += EXT4_XATTR_LEN(last->e_name_len); 518 if (!last->e_value_block && last->e_value_size) { 519 size_t offs = le16_to_cpu(last->e_value_offs); 520 if (offs < *min_offs) 521 *min_offs = offs; 522 } 523 } 524 return (*min_offs - ((void *)last - base) - sizeof(__u32)); 525 } 526 527 struct ext4_xattr_info { 528 int name_index; 529 const char *name; 530 const void *value; 531 size_t value_len; 532 }; 533 534 struct ext4_xattr_search { 535 struct ext4_xattr_entry *first; 536 void *base; 537 void *end; 538 struct ext4_xattr_entry *here; 539 int not_found; 540 }; 541 542 static int 543 ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s) 544 { 545 struct ext4_xattr_entry *last; 546 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name); 547 548 /* Compute min_offs and last. */ 549 last = s->first; 550 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 551 if (!last->e_value_block && last->e_value_size) { 552 size_t offs = le16_to_cpu(last->e_value_offs); 553 if (offs < min_offs) 554 min_offs = offs; 555 } 556 } 557 free = min_offs - ((void *)last - s->base) - sizeof(__u32); 558 if (!s->not_found) { 559 if (!s->here->e_value_block && s->here->e_value_size) { 560 size_t size = le32_to_cpu(s->here->e_value_size); 561 free += EXT4_XATTR_SIZE(size); 562 } 563 free += EXT4_XATTR_LEN(name_len); 564 } 565 if (i->value) { 566 if (free < EXT4_XATTR_SIZE(i->value_len) || 567 free < EXT4_XATTR_LEN(name_len) + 568 EXT4_XATTR_SIZE(i->value_len)) 569 return -ENOSPC; 570 } 571 572 if (i->value && s->not_found) { 573 /* Insert the new name. */ 574 size_t size = EXT4_XATTR_LEN(name_len); 575 size_t rest = (void *)last - (void *)s->here + sizeof(__u32); 576 memmove((void *)s->here + size, s->here, rest); 577 memset(s->here, 0, size); 578 s->here->e_name_index = i->name_index; 579 s->here->e_name_len = name_len; 580 memcpy(s->here->e_name, i->name, name_len); 581 } else { 582 if (!s->here->e_value_block && s->here->e_value_size) { 583 void *first_val = s->base + min_offs; 584 size_t offs = le16_to_cpu(s->here->e_value_offs); 585 void *val = s->base + offs; 586 size_t size = EXT4_XATTR_SIZE( 587 le32_to_cpu(s->here->e_value_size)); 588 589 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) { 590 /* The old and the new value have the same 591 size. Just replace. */ 592 s->here->e_value_size = 593 cpu_to_le32(i->value_len); 594 memset(val + size - EXT4_XATTR_PAD, 0, 595 EXT4_XATTR_PAD); /* Clear pad bytes. */ 596 memcpy(val, i->value, i->value_len); 597 return 0; 598 } 599 600 /* Remove the old value. */ 601 memmove(first_val + size, first_val, val - first_val); 602 memset(first_val, 0, size); 603 s->here->e_value_size = 0; 604 s->here->e_value_offs = 0; 605 min_offs += size; 606 607 /* Adjust all value offsets. */ 608 last = s->first; 609 while (!IS_LAST_ENTRY(last)) { 610 size_t o = le16_to_cpu(last->e_value_offs); 611 if (!last->e_value_block && 612 last->e_value_size && o < offs) 613 last->e_value_offs = 614 cpu_to_le16(o + size); 615 last = EXT4_XATTR_NEXT(last); 616 } 617 } 618 if (!i->value) { 619 /* Remove the old name. */ 620 size_t size = EXT4_XATTR_LEN(name_len); 621 last = ENTRY((void *)last - size); 622 memmove(s->here, (void *)s->here + size, 623 (void *)last - (void *)s->here + sizeof(__u32)); 624 memset(last, 0, size); 625 } 626 } 627 628 if (i->value) { 629 /* Insert the new value. */ 630 s->here->e_value_size = cpu_to_le32(i->value_len); 631 if (i->value_len) { 632 size_t size = EXT4_XATTR_SIZE(i->value_len); 633 void *val = s->base + min_offs - size; 634 s->here->e_value_offs = cpu_to_le16(min_offs - size); 635 memset(val + size - EXT4_XATTR_PAD, 0, 636 EXT4_XATTR_PAD); /* Clear the pad bytes. */ 637 memcpy(val, i->value, i->value_len); 638 } 639 } 640 return 0; 641 } 642 643 struct ext4_xattr_block_find { 644 struct ext4_xattr_search s; 645 struct buffer_head *bh; 646 }; 647 648 static int 649 ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i, 650 struct ext4_xattr_block_find *bs) 651 { 652 struct super_block *sb = inode->i_sb; 653 int error; 654 655 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", 656 i->name_index, i->name, i->value, (long)i->value_len); 657 658 if (EXT4_I(inode)->i_file_acl) { 659 /* The inode already has an extended attribute block. */ 660 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl); 661 error = -EIO; 662 if (!bs->bh) 663 goto cleanup; 664 ea_bdebug(bs->bh, "b_count=%d, refcount=%d", 665 atomic_read(&(bs->bh->b_count)), 666 le32_to_cpu(BHDR(bs->bh)->h_refcount)); 667 if (ext4_xattr_check_block(bs->bh)) { 668 ext4_error(sb, __func__, 669 "inode %lu: bad block %llu", inode->i_ino, 670 EXT4_I(inode)->i_file_acl); 671 error = -EIO; 672 goto cleanup; 673 } 674 /* Find the named attribute. */ 675 bs->s.base = BHDR(bs->bh); 676 bs->s.first = BFIRST(bs->bh); 677 bs->s.end = bs->bh->b_data + bs->bh->b_size; 678 bs->s.here = bs->s.first; 679 error = ext4_xattr_find_entry(&bs->s.here, i->name_index, 680 i->name, bs->bh->b_size, 1); 681 if (error && error != -ENODATA) 682 goto cleanup; 683 bs->s.not_found = error; 684 } 685 error = 0; 686 687 cleanup: 688 return error; 689 } 690 691 static int 692 ext4_xattr_block_set(handle_t *handle, struct inode *inode, 693 struct ext4_xattr_info *i, 694 struct ext4_xattr_block_find *bs) 695 { 696 struct super_block *sb = inode->i_sb; 697 struct buffer_head *new_bh = NULL; 698 struct ext4_xattr_search *s = &bs->s; 699 struct mb_cache_entry *ce = NULL; 700 int error = 0; 701 702 #define header(x) ((struct ext4_xattr_header *)(x)) 703 704 if (i->value && i->value_len > sb->s_blocksize) 705 return -ENOSPC; 706 if (s->base) { 707 ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev, 708 bs->bh->b_blocknr); 709 error = ext4_journal_get_write_access(handle, bs->bh); 710 if (error) 711 goto cleanup; 712 lock_buffer(bs->bh); 713 714 if (header(s->base)->h_refcount == cpu_to_le32(1)) { 715 if (ce) { 716 mb_cache_entry_free(ce); 717 ce = NULL; 718 } 719 ea_bdebug(bs->bh, "modifying in-place"); 720 error = ext4_xattr_set_entry(i, s); 721 if (!error) { 722 if (!IS_LAST_ENTRY(s->first)) 723 ext4_xattr_rehash(header(s->base), 724 s->here); 725 ext4_xattr_cache_insert(bs->bh); 726 } 727 unlock_buffer(bs->bh); 728 if (error == -EIO) 729 goto bad_block; 730 if (!error) 731 error = ext4_handle_dirty_metadata(handle, 732 inode, 733 bs->bh); 734 if (error) 735 goto cleanup; 736 goto inserted; 737 } else { 738 int offset = (char *)s->here - bs->bh->b_data; 739 740 unlock_buffer(bs->bh); 741 jbd2_journal_release_buffer(handle, bs->bh); 742 if (ce) { 743 mb_cache_entry_release(ce); 744 ce = NULL; 745 } 746 ea_bdebug(bs->bh, "cloning"); 747 s->base = kmalloc(bs->bh->b_size, GFP_NOFS); 748 error = -ENOMEM; 749 if (s->base == NULL) 750 goto cleanup; 751 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size); 752 s->first = ENTRY(header(s->base)+1); 753 header(s->base)->h_refcount = cpu_to_le32(1); 754 s->here = ENTRY(s->base + offset); 755 s->end = s->base + bs->bh->b_size; 756 } 757 } else { 758 /* Allocate a buffer where we construct the new block. */ 759 s->base = kzalloc(sb->s_blocksize, GFP_NOFS); 760 /* assert(header == s->base) */ 761 error = -ENOMEM; 762 if (s->base == NULL) 763 goto cleanup; 764 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 765 header(s->base)->h_blocks = cpu_to_le32(1); 766 header(s->base)->h_refcount = cpu_to_le32(1); 767 s->first = ENTRY(header(s->base)+1); 768 s->here = ENTRY(header(s->base)+1); 769 s->end = s->base + sb->s_blocksize; 770 } 771 772 error = ext4_xattr_set_entry(i, s); 773 if (error == -EIO) 774 goto bad_block; 775 if (error) 776 goto cleanup; 777 if (!IS_LAST_ENTRY(s->first)) 778 ext4_xattr_rehash(header(s->base), s->here); 779 780 inserted: 781 if (!IS_LAST_ENTRY(s->first)) { 782 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce); 783 if (new_bh) { 784 /* We found an identical block in the cache. */ 785 if (new_bh == bs->bh) 786 ea_bdebug(new_bh, "keeping"); 787 else { 788 /* The old block is released after updating 789 the inode. */ 790 error = -EDQUOT; 791 if (vfs_dq_alloc_block(inode, 1)) 792 goto cleanup; 793 error = ext4_journal_get_write_access(handle, 794 new_bh); 795 if (error) 796 goto cleanup_dquot; 797 lock_buffer(new_bh); 798 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1); 799 ea_bdebug(new_bh, "reusing; refcount now=%d", 800 le32_to_cpu(BHDR(new_bh)->h_refcount)); 801 unlock_buffer(new_bh); 802 error = ext4_handle_dirty_metadata(handle, 803 inode, 804 new_bh); 805 if (error) 806 goto cleanup_dquot; 807 } 808 mb_cache_entry_release(ce); 809 ce = NULL; 810 } else if (bs->bh && s->base == bs->bh->b_data) { 811 /* We were modifying this block in-place. */ 812 ea_bdebug(bs->bh, "keeping this block"); 813 new_bh = bs->bh; 814 get_bh(new_bh); 815 } else { 816 /* We need to allocate a new block */ 817 ext4_fsblk_t goal, block; 818 819 goal = ext4_group_first_block_no(sb, 820 EXT4_I(inode)->i_block_group); 821 822 /* non-extent files can't have physical blocks past 2^32 */ 823 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 824 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS; 825 826 block = ext4_new_meta_blocks(handle, inode, 827 goal, NULL, &error); 828 if (error) 829 goto cleanup; 830 831 if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) 832 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS); 833 834 ea_idebug(inode, "creating block %d", block); 835 836 new_bh = sb_getblk(sb, block); 837 if (!new_bh) { 838 getblk_failed: 839 ext4_free_blocks(handle, inode, 0, block, 1, 840 EXT4_FREE_BLOCKS_METADATA); 841 error = -EIO; 842 goto cleanup; 843 } 844 lock_buffer(new_bh); 845 error = ext4_journal_get_create_access(handle, new_bh); 846 if (error) { 847 unlock_buffer(new_bh); 848 goto getblk_failed; 849 } 850 memcpy(new_bh->b_data, s->base, new_bh->b_size); 851 set_buffer_uptodate(new_bh); 852 unlock_buffer(new_bh); 853 ext4_xattr_cache_insert(new_bh); 854 error = ext4_handle_dirty_metadata(handle, 855 inode, new_bh); 856 if (error) 857 goto cleanup; 858 } 859 } 860 861 /* Update the inode. */ 862 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; 863 864 /* Drop the previous xattr block. */ 865 if (bs->bh && bs->bh != new_bh) 866 ext4_xattr_release_block(handle, inode, bs->bh); 867 error = 0; 868 869 cleanup: 870 if (ce) 871 mb_cache_entry_release(ce); 872 brelse(new_bh); 873 if (!(bs->bh && s->base == bs->bh->b_data)) 874 kfree(s->base); 875 876 return error; 877 878 cleanup_dquot: 879 vfs_dq_free_block(inode, 1); 880 goto cleanup; 881 882 bad_block: 883 ext4_error(inode->i_sb, __func__, 884 "inode %lu: bad block %llu", inode->i_ino, 885 EXT4_I(inode)->i_file_acl); 886 goto cleanup; 887 888 #undef header 889 } 890 891 struct ext4_xattr_ibody_find { 892 struct ext4_xattr_search s; 893 struct ext4_iloc iloc; 894 }; 895 896 static int 897 ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, 898 struct ext4_xattr_ibody_find *is) 899 { 900 struct ext4_xattr_ibody_header *header; 901 struct ext4_inode *raw_inode; 902 int error; 903 904 if (EXT4_I(inode)->i_extra_isize == 0) 905 return 0; 906 raw_inode = ext4_raw_inode(&is->iloc); 907 header = IHDR(inode, raw_inode); 908 is->s.base = is->s.first = IFIRST(header); 909 is->s.here = is->s.first; 910 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 911 if (EXT4_I(inode)->i_state & EXT4_STATE_XATTR) { 912 error = ext4_xattr_check_names(IFIRST(header), is->s.end); 913 if (error) 914 return error; 915 /* Find the named attribute. */ 916 error = ext4_xattr_find_entry(&is->s.here, i->name_index, 917 i->name, is->s.end - 918 (void *)is->s.base, 0); 919 if (error && error != -ENODATA) 920 return error; 921 is->s.not_found = error; 922 } 923 return 0; 924 } 925 926 static int 927 ext4_xattr_ibody_set(handle_t *handle, struct inode *inode, 928 struct ext4_xattr_info *i, 929 struct ext4_xattr_ibody_find *is) 930 { 931 struct ext4_xattr_ibody_header *header; 932 struct ext4_xattr_search *s = &is->s; 933 int error; 934 935 if (EXT4_I(inode)->i_extra_isize == 0) 936 return -ENOSPC; 937 error = ext4_xattr_set_entry(i, s); 938 if (error) 939 return error; 940 header = IHDR(inode, ext4_raw_inode(&is->iloc)); 941 if (!IS_LAST_ENTRY(s->first)) { 942 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 943 EXT4_I(inode)->i_state |= EXT4_STATE_XATTR; 944 } else { 945 header->h_magic = cpu_to_le32(0); 946 EXT4_I(inode)->i_state &= ~EXT4_STATE_XATTR; 947 } 948 return 0; 949 } 950 951 /* 952 * ext4_xattr_set_handle() 953 * 954 * Create, replace or remove an extended attribute for this inode. Buffer 955 * is NULL to remove an existing extended attribute, and non-NULL to 956 * either replace an existing extended attribute, or create a new extended 957 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 958 * specify that an extended attribute must exist and must not exist 959 * previous to the call, respectively. 960 * 961 * Returns 0, or a negative error number on failure. 962 */ 963 int 964 ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, 965 const char *name, const void *value, size_t value_len, 966 int flags) 967 { 968 struct ext4_xattr_info i = { 969 .name_index = name_index, 970 .name = name, 971 .value = value, 972 .value_len = value_len, 973 974 }; 975 struct ext4_xattr_ibody_find is = { 976 .s = { .not_found = -ENODATA, }, 977 }; 978 struct ext4_xattr_block_find bs = { 979 .s = { .not_found = -ENODATA, }, 980 }; 981 unsigned long no_expand; 982 int error; 983 984 if (!name) 985 return -EINVAL; 986 if (strlen(name) > 255) 987 return -ERANGE; 988 down_write(&EXT4_I(inode)->xattr_sem); 989 no_expand = EXT4_I(inode)->i_state & EXT4_STATE_NO_EXPAND; 990 EXT4_I(inode)->i_state |= EXT4_STATE_NO_EXPAND; 991 992 error = ext4_get_inode_loc(inode, &is.iloc); 993 if (error) 994 goto cleanup; 995 996 error = ext4_journal_get_write_access(handle, is.iloc.bh); 997 if (error) 998 goto cleanup; 999 1000 if (EXT4_I(inode)->i_state & EXT4_STATE_NEW) { 1001 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc); 1002 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); 1003 EXT4_I(inode)->i_state &= ~EXT4_STATE_NEW; 1004 } 1005 1006 error = ext4_xattr_ibody_find(inode, &i, &is); 1007 if (error) 1008 goto cleanup; 1009 if (is.s.not_found) 1010 error = ext4_xattr_block_find(inode, &i, &bs); 1011 if (error) 1012 goto cleanup; 1013 if (is.s.not_found && bs.s.not_found) { 1014 error = -ENODATA; 1015 if (flags & XATTR_REPLACE) 1016 goto cleanup; 1017 error = 0; 1018 if (!value) 1019 goto cleanup; 1020 } else { 1021 error = -EEXIST; 1022 if (flags & XATTR_CREATE) 1023 goto cleanup; 1024 } 1025 if (!value) { 1026 if (!is.s.not_found) 1027 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1028 else if (!bs.s.not_found) 1029 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1030 } else { 1031 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1032 if (!error && !bs.s.not_found) { 1033 i.value = NULL; 1034 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1035 } else if (error == -ENOSPC) { 1036 if (EXT4_I(inode)->i_file_acl && !bs.s.base) { 1037 error = ext4_xattr_block_find(inode, &i, &bs); 1038 if (error) 1039 goto cleanup; 1040 } 1041 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1042 if (error) 1043 goto cleanup; 1044 if (!is.s.not_found) { 1045 i.value = NULL; 1046 error = ext4_xattr_ibody_set(handle, inode, &i, 1047 &is); 1048 } 1049 } 1050 } 1051 if (!error) { 1052 ext4_xattr_update_super_block(handle, inode->i_sb); 1053 inode->i_ctime = ext4_current_time(inode); 1054 if (!value) 1055 EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND; 1056 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc); 1057 /* 1058 * The bh is consumed by ext4_mark_iloc_dirty, even with 1059 * error != 0. 1060 */ 1061 is.iloc.bh = NULL; 1062 if (IS_SYNC(inode)) 1063 ext4_handle_sync(handle); 1064 } 1065 1066 cleanup: 1067 brelse(is.iloc.bh); 1068 brelse(bs.bh); 1069 if (no_expand == 0) 1070 EXT4_I(inode)->i_state &= ~EXT4_STATE_NO_EXPAND; 1071 up_write(&EXT4_I(inode)->xattr_sem); 1072 return error; 1073 } 1074 1075 /* 1076 * ext4_xattr_set() 1077 * 1078 * Like ext4_xattr_set_handle, but start from an inode. This extended 1079 * attribute modification is a filesystem transaction by itself. 1080 * 1081 * Returns 0, or a negative error number on failure. 1082 */ 1083 int 1084 ext4_xattr_set(struct inode *inode, int name_index, const char *name, 1085 const void *value, size_t value_len, int flags) 1086 { 1087 handle_t *handle; 1088 int error, retries = 0; 1089 1090 retry: 1091 handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb)); 1092 if (IS_ERR(handle)) { 1093 error = PTR_ERR(handle); 1094 } else { 1095 int error2; 1096 1097 error = ext4_xattr_set_handle(handle, inode, name_index, name, 1098 value, value_len, flags); 1099 error2 = ext4_journal_stop(handle); 1100 if (error == -ENOSPC && 1101 ext4_should_retry_alloc(inode->i_sb, &retries)) 1102 goto retry; 1103 if (error == 0) 1104 error = error2; 1105 } 1106 1107 return error; 1108 } 1109 1110 /* 1111 * Shift the EA entries in the inode to create space for the increased 1112 * i_extra_isize. 1113 */ 1114 static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry, 1115 int value_offs_shift, void *to, 1116 void *from, size_t n, int blocksize) 1117 { 1118 struct ext4_xattr_entry *last = entry; 1119 int new_offs; 1120 1121 /* Adjust the value offsets of the entries */ 1122 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1123 if (!last->e_value_block && last->e_value_size) { 1124 new_offs = le16_to_cpu(last->e_value_offs) + 1125 value_offs_shift; 1126 BUG_ON(new_offs + le32_to_cpu(last->e_value_size) 1127 > blocksize); 1128 last->e_value_offs = cpu_to_le16(new_offs); 1129 } 1130 } 1131 /* Shift the entries by n bytes */ 1132 memmove(to, from, n); 1133 } 1134 1135 /* 1136 * Expand an inode by new_extra_isize bytes when EAs are present. 1137 * Returns 0 on success or negative error number on failure. 1138 */ 1139 int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, 1140 struct ext4_inode *raw_inode, handle_t *handle) 1141 { 1142 struct ext4_xattr_ibody_header *header; 1143 struct ext4_xattr_entry *entry, *last, *first; 1144 struct buffer_head *bh = NULL; 1145 struct ext4_xattr_ibody_find *is = NULL; 1146 struct ext4_xattr_block_find *bs = NULL; 1147 char *buffer = NULL, *b_entry_name = NULL; 1148 size_t min_offs, free; 1149 int total_ino, total_blk; 1150 void *base, *start, *end; 1151 int extra_isize = 0, error = 0, tried_min_extra_isize = 0; 1152 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize); 1153 1154 down_write(&EXT4_I(inode)->xattr_sem); 1155 retry: 1156 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) { 1157 up_write(&EXT4_I(inode)->xattr_sem); 1158 return 0; 1159 } 1160 1161 header = IHDR(inode, raw_inode); 1162 entry = IFIRST(header); 1163 1164 /* 1165 * Check if enough free space is available in the inode to shift the 1166 * entries ahead by new_extra_isize. 1167 */ 1168 1169 base = start = entry; 1170 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 1171 min_offs = end - base; 1172 last = entry; 1173 total_ino = sizeof(struct ext4_xattr_ibody_header); 1174 1175 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino); 1176 if (free >= new_extra_isize) { 1177 entry = IFIRST(header); 1178 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize 1179 - new_extra_isize, (void *)raw_inode + 1180 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize, 1181 (void *)header, total_ino, 1182 inode->i_sb->s_blocksize); 1183 EXT4_I(inode)->i_extra_isize = new_extra_isize; 1184 error = 0; 1185 goto cleanup; 1186 } 1187 1188 /* 1189 * Enough free space isn't available in the inode, check if 1190 * EA block can hold new_extra_isize bytes. 1191 */ 1192 if (EXT4_I(inode)->i_file_acl) { 1193 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1194 error = -EIO; 1195 if (!bh) 1196 goto cleanup; 1197 if (ext4_xattr_check_block(bh)) { 1198 ext4_error(inode->i_sb, __func__, 1199 "inode %lu: bad block %llu", inode->i_ino, 1200 EXT4_I(inode)->i_file_acl); 1201 error = -EIO; 1202 goto cleanup; 1203 } 1204 base = BHDR(bh); 1205 first = BFIRST(bh); 1206 end = bh->b_data + bh->b_size; 1207 min_offs = end - base; 1208 free = ext4_xattr_free_space(first, &min_offs, base, 1209 &total_blk); 1210 if (free < new_extra_isize) { 1211 if (!tried_min_extra_isize && s_min_extra_isize) { 1212 tried_min_extra_isize++; 1213 new_extra_isize = s_min_extra_isize; 1214 brelse(bh); 1215 goto retry; 1216 } 1217 error = -1; 1218 goto cleanup; 1219 } 1220 } else { 1221 free = inode->i_sb->s_blocksize; 1222 } 1223 1224 while (new_extra_isize > 0) { 1225 size_t offs, size, entry_size; 1226 struct ext4_xattr_entry *small_entry = NULL; 1227 struct ext4_xattr_info i = { 1228 .value = NULL, 1229 .value_len = 0, 1230 }; 1231 unsigned int total_size; /* EA entry size + value size */ 1232 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */ 1233 unsigned int min_total_size = ~0U; 1234 1235 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS); 1236 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS); 1237 if (!is || !bs) { 1238 error = -ENOMEM; 1239 goto cleanup; 1240 } 1241 1242 is->s.not_found = -ENODATA; 1243 bs->s.not_found = -ENODATA; 1244 is->iloc.bh = NULL; 1245 bs->bh = NULL; 1246 1247 last = IFIRST(header); 1248 /* Find the entry best suited to be pushed into EA block */ 1249 entry = NULL; 1250 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1251 total_size = 1252 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) + 1253 EXT4_XATTR_LEN(last->e_name_len); 1254 if (total_size <= free && total_size < min_total_size) { 1255 if (total_size < new_extra_isize) { 1256 small_entry = last; 1257 } else { 1258 entry = last; 1259 min_total_size = total_size; 1260 } 1261 } 1262 } 1263 1264 if (entry == NULL) { 1265 if (small_entry) { 1266 entry = small_entry; 1267 } else { 1268 if (!tried_min_extra_isize && 1269 s_min_extra_isize) { 1270 tried_min_extra_isize++; 1271 new_extra_isize = s_min_extra_isize; 1272 goto retry; 1273 } 1274 error = -1; 1275 goto cleanup; 1276 } 1277 } 1278 offs = le16_to_cpu(entry->e_value_offs); 1279 size = le32_to_cpu(entry->e_value_size); 1280 entry_size = EXT4_XATTR_LEN(entry->e_name_len); 1281 i.name_index = entry->e_name_index, 1282 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS); 1283 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS); 1284 if (!buffer || !b_entry_name) { 1285 error = -ENOMEM; 1286 goto cleanup; 1287 } 1288 /* Save the entry name and the entry value */ 1289 memcpy(buffer, (void *)IFIRST(header) + offs, 1290 EXT4_XATTR_SIZE(size)); 1291 memcpy(b_entry_name, entry->e_name, entry->e_name_len); 1292 b_entry_name[entry->e_name_len] = '\0'; 1293 i.name = b_entry_name; 1294 1295 error = ext4_get_inode_loc(inode, &is->iloc); 1296 if (error) 1297 goto cleanup; 1298 1299 error = ext4_xattr_ibody_find(inode, &i, is); 1300 if (error) 1301 goto cleanup; 1302 1303 /* Remove the chosen entry from the inode */ 1304 error = ext4_xattr_ibody_set(handle, inode, &i, is); 1305 1306 entry = IFIRST(header); 1307 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize) 1308 shift_bytes = new_extra_isize; 1309 else 1310 shift_bytes = entry_size + size; 1311 /* Adjust the offsets and shift the remaining entries ahead */ 1312 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize - 1313 shift_bytes, (void *)raw_inode + 1314 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes, 1315 (void *)header, total_ino - entry_size, 1316 inode->i_sb->s_blocksize); 1317 1318 extra_isize += shift_bytes; 1319 new_extra_isize -= shift_bytes; 1320 EXT4_I(inode)->i_extra_isize = extra_isize; 1321 1322 i.name = b_entry_name; 1323 i.value = buffer; 1324 i.value_len = size; 1325 error = ext4_xattr_block_find(inode, &i, bs); 1326 if (error) 1327 goto cleanup; 1328 1329 /* Add entry which was removed from the inode into the block */ 1330 error = ext4_xattr_block_set(handle, inode, &i, bs); 1331 if (error) 1332 goto cleanup; 1333 kfree(b_entry_name); 1334 kfree(buffer); 1335 b_entry_name = NULL; 1336 buffer = NULL; 1337 brelse(is->iloc.bh); 1338 kfree(is); 1339 kfree(bs); 1340 } 1341 brelse(bh); 1342 up_write(&EXT4_I(inode)->xattr_sem); 1343 return 0; 1344 1345 cleanup: 1346 kfree(b_entry_name); 1347 kfree(buffer); 1348 if (is) 1349 brelse(is->iloc.bh); 1350 kfree(is); 1351 kfree(bs); 1352 brelse(bh); 1353 up_write(&EXT4_I(inode)->xattr_sem); 1354 return error; 1355 } 1356 1357 1358 1359 /* 1360 * ext4_xattr_delete_inode() 1361 * 1362 * Free extended attribute resources associated with this inode. This 1363 * is called immediately before an inode is freed. We have exclusive 1364 * access to the inode. 1365 */ 1366 void 1367 ext4_xattr_delete_inode(handle_t *handle, struct inode *inode) 1368 { 1369 struct buffer_head *bh = NULL; 1370 1371 if (!EXT4_I(inode)->i_file_acl) 1372 goto cleanup; 1373 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1374 if (!bh) { 1375 ext4_error(inode->i_sb, __func__, 1376 "inode %lu: block %llu read error", inode->i_ino, 1377 EXT4_I(inode)->i_file_acl); 1378 goto cleanup; 1379 } 1380 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 1381 BHDR(bh)->h_blocks != cpu_to_le32(1)) { 1382 ext4_error(inode->i_sb, __func__, 1383 "inode %lu: bad block %llu", inode->i_ino, 1384 EXT4_I(inode)->i_file_acl); 1385 goto cleanup; 1386 } 1387 ext4_xattr_release_block(handle, inode, bh); 1388 EXT4_I(inode)->i_file_acl = 0; 1389 1390 cleanup: 1391 brelse(bh); 1392 } 1393 1394 /* 1395 * ext4_xattr_put_super() 1396 * 1397 * This is called when a file system is unmounted. 1398 */ 1399 void 1400 ext4_xattr_put_super(struct super_block *sb) 1401 { 1402 mb_cache_shrink(sb->s_bdev); 1403 } 1404 1405 /* 1406 * ext4_xattr_cache_insert() 1407 * 1408 * Create a new entry in the extended attribute cache, and insert 1409 * it unless such an entry is already in the cache. 1410 * 1411 * Returns 0, or a negative error number on failure. 1412 */ 1413 static void 1414 ext4_xattr_cache_insert(struct buffer_head *bh) 1415 { 1416 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash); 1417 struct mb_cache_entry *ce; 1418 int error; 1419 1420 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS); 1421 if (!ce) { 1422 ea_bdebug(bh, "out of memory"); 1423 return; 1424 } 1425 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash); 1426 if (error) { 1427 mb_cache_entry_free(ce); 1428 if (error == -EBUSY) { 1429 ea_bdebug(bh, "already in cache"); 1430 error = 0; 1431 } 1432 } else { 1433 ea_bdebug(bh, "inserting [%x]", (int)hash); 1434 mb_cache_entry_release(ce); 1435 } 1436 } 1437 1438 /* 1439 * ext4_xattr_cmp() 1440 * 1441 * Compare two extended attribute blocks for equality. 1442 * 1443 * Returns 0 if the blocks are equal, 1 if they differ, and 1444 * a negative error number on errors. 1445 */ 1446 static int 1447 ext4_xattr_cmp(struct ext4_xattr_header *header1, 1448 struct ext4_xattr_header *header2) 1449 { 1450 struct ext4_xattr_entry *entry1, *entry2; 1451 1452 entry1 = ENTRY(header1+1); 1453 entry2 = ENTRY(header2+1); 1454 while (!IS_LAST_ENTRY(entry1)) { 1455 if (IS_LAST_ENTRY(entry2)) 1456 return 1; 1457 if (entry1->e_hash != entry2->e_hash || 1458 entry1->e_name_index != entry2->e_name_index || 1459 entry1->e_name_len != entry2->e_name_len || 1460 entry1->e_value_size != entry2->e_value_size || 1461 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) 1462 return 1; 1463 if (entry1->e_value_block != 0 || entry2->e_value_block != 0) 1464 return -EIO; 1465 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), 1466 (char *)header2 + le16_to_cpu(entry2->e_value_offs), 1467 le32_to_cpu(entry1->e_value_size))) 1468 return 1; 1469 1470 entry1 = EXT4_XATTR_NEXT(entry1); 1471 entry2 = EXT4_XATTR_NEXT(entry2); 1472 } 1473 if (!IS_LAST_ENTRY(entry2)) 1474 return 1; 1475 return 0; 1476 } 1477 1478 /* 1479 * ext4_xattr_cache_find() 1480 * 1481 * Find an identical extended attribute block. 1482 * 1483 * Returns a pointer to the block found, or NULL if such a block was 1484 * not found or an error occurred. 1485 */ 1486 static struct buffer_head * 1487 ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header, 1488 struct mb_cache_entry **pce) 1489 { 1490 __u32 hash = le32_to_cpu(header->h_hash); 1491 struct mb_cache_entry *ce; 1492 1493 if (!header->h_hash) 1494 return NULL; /* never share */ 1495 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); 1496 again: 1497 ce = mb_cache_entry_find_first(ext4_xattr_cache, 0, 1498 inode->i_sb->s_bdev, hash); 1499 while (ce) { 1500 struct buffer_head *bh; 1501 1502 if (IS_ERR(ce)) { 1503 if (PTR_ERR(ce) == -EAGAIN) 1504 goto again; 1505 break; 1506 } 1507 bh = sb_bread(inode->i_sb, ce->e_block); 1508 if (!bh) { 1509 ext4_error(inode->i_sb, __func__, 1510 "inode %lu: block %lu read error", 1511 inode->i_ino, (unsigned long) ce->e_block); 1512 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >= 1513 EXT4_XATTR_REFCOUNT_MAX) { 1514 ea_idebug(inode, "block %lu refcount %d>=%d", 1515 (unsigned long) ce->e_block, 1516 le32_to_cpu(BHDR(bh)->h_refcount), 1517 EXT4_XATTR_REFCOUNT_MAX); 1518 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) { 1519 *pce = ce; 1520 return bh; 1521 } 1522 brelse(bh); 1523 ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash); 1524 } 1525 return NULL; 1526 } 1527 1528 #define NAME_HASH_SHIFT 5 1529 #define VALUE_HASH_SHIFT 16 1530 1531 /* 1532 * ext4_xattr_hash_entry() 1533 * 1534 * Compute the hash of an extended attribute. 1535 */ 1536 static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header, 1537 struct ext4_xattr_entry *entry) 1538 { 1539 __u32 hash = 0; 1540 char *name = entry->e_name; 1541 int n; 1542 1543 for (n = 0; n < entry->e_name_len; n++) { 1544 hash = (hash << NAME_HASH_SHIFT) ^ 1545 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ 1546 *name++; 1547 } 1548 1549 if (entry->e_value_block == 0 && entry->e_value_size != 0) { 1550 __le32 *value = (__le32 *)((char *)header + 1551 le16_to_cpu(entry->e_value_offs)); 1552 for (n = (le32_to_cpu(entry->e_value_size) + 1553 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) { 1554 hash = (hash << VALUE_HASH_SHIFT) ^ 1555 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ 1556 le32_to_cpu(*value++); 1557 } 1558 } 1559 entry->e_hash = cpu_to_le32(hash); 1560 } 1561 1562 #undef NAME_HASH_SHIFT 1563 #undef VALUE_HASH_SHIFT 1564 1565 #define BLOCK_HASH_SHIFT 16 1566 1567 /* 1568 * ext4_xattr_rehash() 1569 * 1570 * Re-compute the extended attribute hash value after an entry has changed. 1571 */ 1572 static void ext4_xattr_rehash(struct ext4_xattr_header *header, 1573 struct ext4_xattr_entry *entry) 1574 { 1575 struct ext4_xattr_entry *here; 1576 __u32 hash = 0; 1577 1578 ext4_xattr_hash_entry(header, entry); 1579 here = ENTRY(header+1); 1580 while (!IS_LAST_ENTRY(here)) { 1581 if (!here->e_hash) { 1582 /* Block is not shared if an entry's hash value == 0 */ 1583 hash = 0; 1584 break; 1585 } 1586 hash = (hash << BLOCK_HASH_SHIFT) ^ 1587 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ 1588 le32_to_cpu(here->e_hash); 1589 here = EXT4_XATTR_NEXT(here); 1590 } 1591 header->h_hash = cpu_to_le32(hash); 1592 } 1593 1594 #undef BLOCK_HASH_SHIFT 1595 1596 int __init 1597 init_ext4_xattr(void) 1598 { 1599 ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL, 1600 sizeof(struct mb_cache_entry) + 1601 sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6); 1602 if (!ext4_xattr_cache) 1603 return -ENOMEM; 1604 return 0; 1605 } 1606 1607 void 1608 exit_ext4_xattr(void) 1609 { 1610 if (ext4_xattr_cache) 1611 mb_cache_destroy(ext4_xattr_cache); 1612 ext4_xattr_cache = NULL; 1613 } 1614