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, f...) do { \ 65 printk(KERN_DEBUG "inode %s:%lu: ", \ 66 inode->i_sb->s_id, inode->i_ino); \ 67 printk(f); \ 68 printk("\n"); \ 69 } while (0) 70# define ea_bdebug(bh, f...) do { \ 71 char b[BDEVNAME_SIZE]; \ 72 printk(KERN_DEBUG "block %s:%lu: ", \ 73 bdevname(bh->b_bdev, b), \ 74 (unsigned long) bh->b_blocknr); \ 75 printk(f); \ 76 printk("\n"); \ 77 } while (0) 78#else 79# define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__) 80# define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__) 81#endif 82 83static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *); 84static struct buffer_head *ext4_xattr_cache_find(struct inode *, 85 struct ext4_xattr_header *, 86 struct mb_cache_entry **); 87static void ext4_xattr_rehash(struct ext4_xattr_header *, 88 struct ext4_xattr_entry *); 89static int ext4_xattr_list(struct dentry *dentry, char *buffer, 90 size_t buffer_size); 91 92static const struct xattr_handler *ext4_xattr_handler_map[] = { 93 [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler, 94#ifdef CONFIG_EXT4_FS_POSIX_ACL 95 [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler, 96 [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler, 97#endif 98 [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler, 99#ifdef CONFIG_EXT4_FS_SECURITY 100 [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler, 101#endif 102}; 103 104const struct xattr_handler *ext4_xattr_handlers[] = { 105 &ext4_xattr_user_handler, 106 &ext4_xattr_trusted_handler, 107#ifdef CONFIG_EXT4_FS_POSIX_ACL 108 &posix_acl_access_xattr_handler, 109 &posix_acl_default_xattr_handler, 110#endif 111#ifdef CONFIG_EXT4_FS_SECURITY 112 &ext4_xattr_security_handler, 113#endif 114 NULL 115}; 116 117#define EXT4_GET_MB_CACHE(inode) (((struct ext4_sb_info *) \ 118 inode->i_sb->s_fs_info)->s_mb_cache) 119 120static __le32 ext4_xattr_block_csum(struct inode *inode, 121 sector_t block_nr, 122 struct ext4_xattr_header *hdr) 123{ 124 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); 125 __u32 csum; 126 __le32 save_csum; 127 __le64 dsk_block_nr = cpu_to_le64(block_nr); 128 129 save_csum = hdr->h_checksum; 130 hdr->h_checksum = 0; 131 csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr, 132 sizeof(dsk_block_nr)); 133 csum = ext4_chksum(sbi, csum, (__u8 *)hdr, 134 EXT4_BLOCK_SIZE(inode->i_sb)); 135 136 hdr->h_checksum = save_csum; 137 return cpu_to_le32(csum); 138} 139 140static int ext4_xattr_block_csum_verify(struct inode *inode, 141 sector_t block_nr, 142 struct ext4_xattr_header *hdr) 143{ 144 if (ext4_has_metadata_csum(inode->i_sb) && 145 (hdr->h_checksum != ext4_xattr_block_csum(inode, block_nr, hdr))) 146 return 0; 147 return 1; 148} 149 150static void ext4_xattr_block_csum_set(struct inode *inode, 151 sector_t block_nr, 152 struct ext4_xattr_header *hdr) 153{ 154 if (!ext4_has_metadata_csum(inode->i_sb)) 155 return; 156 157 hdr->h_checksum = ext4_xattr_block_csum(inode, block_nr, hdr); 158} 159 160static inline int ext4_handle_dirty_xattr_block(handle_t *handle, 161 struct inode *inode, 162 struct buffer_head *bh) 163{ 164 ext4_xattr_block_csum_set(inode, bh->b_blocknr, BHDR(bh)); 165 return ext4_handle_dirty_metadata(handle, inode, bh); 166} 167 168static inline const struct xattr_handler * 169ext4_xattr_handler(int name_index) 170{ 171 const struct xattr_handler *handler = NULL; 172 173 if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map)) 174 handler = ext4_xattr_handler_map[name_index]; 175 return handler; 176} 177 178/* 179 * Inode operation listxattr() 180 * 181 * d_inode(dentry)->i_mutex: don't care 182 */ 183ssize_t 184ext4_listxattr(struct dentry *dentry, char *buffer, size_t size) 185{ 186 return ext4_xattr_list(dentry, buffer, size); 187} 188 189static int 190ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end, 191 void *value_start) 192{ 193 struct ext4_xattr_entry *e = entry; 194 195 while (!IS_LAST_ENTRY(e)) { 196 struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e); 197 if ((void *)next >= end) 198 return -EIO; 199 e = next; 200 } 201 202 while (!IS_LAST_ENTRY(entry)) { 203 if (entry->e_value_size != 0 && 204 (value_start + le16_to_cpu(entry->e_value_offs) < 205 (void *)e + sizeof(__u32) || 206 value_start + le16_to_cpu(entry->e_value_offs) + 207 le32_to_cpu(entry->e_value_size) > end)) 208 return -EIO; 209 entry = EXT4_XATTR_NEXT(entry); 210 } 211 212 return 0; 213} 214 215static inline int 216ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh) 217{ 218 int error; 219 220 if (buffer_verified(bh)) 221 return 0; 222 223 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 224 BHDR(bh)->h_blocks != cpu_to_le32(1)) 225 return -EIO; 226 if (!ext4_xattr_block_csum_verify(inode, bh->b_blocknr, BHDR(bh))) 227 return -EIO; 228 error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size, 229 bh->b_data); 230 if (!error) 231 set_buffer_verified(bh); 232 return error; 233} 234 235static inline int 236ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size) 237{ 238 size_t value_size = le32_to_cpu(entry->e_value_size); 239 240 if (entry->e_value_block != 0 || value_size > size || 241 le16_to_cpu(entry->e_value_offs) + value_size > size) 242 return -EIO; 243 return 0; 244} 245 246static int 247ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index, 248 const char *name, size_t size, int sorted) 249{ 250 struct ext4_xattr_entry *entry; 251 size_t name_len; 252 int cmp = 1; 253 254 if (name == NULL) 255 return -EINVAL; 256 name_len = strlen(name); 257 entry = *pentry; 258 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 259 cmp = name_index - entry->e_name_index; 260 if (!cmp) 261 cmp = name_len - entry->e_name_len; 262 if (!cmp) 263 cmp = memcmp(name, entry->e_name, name_len); 264 if (cmp <= 0 && (sorted || cmp == 0)) 265 break; 266 } 267 *pentry = entry; 268 if (!cmp && ext4_xattr_check_entry(entry, size)) 269 return -EIO; 270 return cmp ? -ENODATA : 0; 271} 272 273static int 274ext4_xattr_block_get(struct inode *inode, int name_index, const char *name, 275 void *buffer, size_t buffer_size) 276{ 277 struct buffer_head *bh = NULL; 278 struct ext4_xattr_entry *entry; 279 size_t size; 280 int error; 281 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 282 283 ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", 284 name_index, name, buffer, (long)buffer_size); 285 286 error = -ENODATA; 287 if (!EXT4_I(inode)->i_file_acl) 288 goto cleanup; 289 ea_idebug(inode, "reading block %llu", 290 (unsigned long long)EXT4_I(inode)->i_file_acl); 291 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 292 if (!bh) 293 goto cleanup; 294 ea_bdebug(bh, "b_count=%d, refcount=%d", 295 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 296 if (ext4_xattr_check_block(inode, bh)) { 297bad_block: 298 EXT4_ERROR_INODE(inode, "bad block %llu", 299 EXT4_I(inode)->i_file_acl); 300 error = -EIO; 301 goto cleanup; 302 } 303 ext4_xattr_cache_insert(ext4_mb_cache, bh); 304 entry = BFIRST(bh); 305 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1); 306 if (error == -EIO) 307 goto bad_block; 308 if (error) 309 goto cleanup; 310 size = le32_to_cpu(entry->e_value_size); 311 if (buffer) { 312 error = -ERANGE; 313 if (size > buffer_size) 314 goto cleanup; 315 memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), 316 size); 317 } 318 error = size; 319 320cleanup: 321 brelse(bh); 322 return error; 323} 324 325int 326ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name, 327 void *buffer, size_t buffer_size) 328{ 329 struct ext4_xattr_ibody_header *header; 330 struct ext4_xattr_entry *entry; 331 struct ext4_inode *raw_inode; 332 struct ext4_iloc iloc; 333 size_t size; 334 void *end; 335 int error; 336 337 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR)) 338 return -ENODATA; 339 error = ext4_get_inode_loc(inode, &iloc); 340 if (error) 341 return error; 342 raw_inode = ext4_raw_inode(&iloc); 343 header = IHDR(inode, raw_inode); 344 entry = IFIRST(header); 345 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 346 error = ext4_xattr_check_names(entry, end, entry); 347 if (error) 348 goto cleanup; 349 error = ext4_xattr_find_entry(&entry, name_index, name, 350 end - (void *)entry, 0); 351 if (error) 352 goto cleanup; 353 size = le32_to_cpu(entry->e_value_size); 354 if (buffer) { 355 error = -ERANGE; 356 if (size > buffer_size) 357 goto cleanup; 358 memcpy(buffer, (void *)IFIRST(header) + 359 le16_to_cpu(entry->e_value_offs), size); 360 } 361 error = size; 362 363cleanup: 364 brelse(iloc.bh); 365 return error; 366} 367 368/* 369 * ext4_xattr_get() 370 * 371 * Copy an extended attribute into the buffer 372 * provided, or compute the buffer size required. 373 * Buffer is NULL to compute the size of the buffer required. 374 * 375 * Returns a negative error number on failure, or the number of bytes 376 * used / required on success. 377 */ 378int 379ext4_xattr_get(struct inode *inode, int name_index, const char *name, 380 void *buffer, size_t buffer_size) 381{ 382 int error; 383 384 if (strlen(name) > 255) 385 return -ERANGE; 386 387 down_read(&EXT4_I(inode)->xattr_sem); 388 error = ext4_xattr_ibody_get(inode, name_index, name, buffer, 389 buffer_size); 390 if (error == -ENODATA) 391 error = ext4_xattr_block_get(inode, name_index, name, buffer, 392 buffer_size); 393 up_read(&EXT4_I(inode)->xattr_sem); 394 return error; 395} 396 397static int 398ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry, 399 char *buffer, size_t buffer_size) 400{ 401 size_t rest = buffer_size; 402 403 for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { 404 const struct xattr_handler *handler = 405 ext4_xattr_handler(entry->e_name_index); 406 407 if (handler) { 408 size_t size = handler->list(dentry, buffer, rest, 409 entry->e_name, 410 entry->e_name_len, 411 handler->flags); 412 if (buffer) { 413 if (size > rest) 414 return -ERANGE; 415 buffer += size; 416 } 417 rest -= size; 418 } 419 } 420 return buffer_size - rest; 421} 422 423static int 424ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size) 425{ 426 struct inode *inode = d_inode(dentry); 427 struct buffer_head *bh = NULL; 428 int error; 429 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 430 431 ea_idebug(inode, "buffer=%p, buffer_size=%ld", 432 buffer, (long)buffer_size); 433 434 error = 0; 435 if (!EXT4_I(inode)->i_file_acl) 436 goto cleanup; 437 ea_idebug(inode, "reading block %llu", 438 (unsigned long long)EXT4_I(inode)->i_file_acl); 439 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 440 error = -EIO; 441 if (!bh) 442 goto cleanup; 443 ea_bdebug(bh, "b_count=%d, refcount=%d", 444 atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); 445 if (ext4_xattr_check_block(inode, bh)) { 446 EXT4_ERROR_INODE(inode, "bad block %llu", 447 EXT4_I(inode)->i_file_acl); 448 error = -EIO; 449 goto cleanup; 450 } 451 ext4_xattr_cache_insert(ext4_mb_cache, bh); 452 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size); 453 454cleanup: 455 brelse(bh); 456 457 return error; 458} 459 460static int 461ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size) 462{ 463 struct inode *inode = d_inode(dentry); 464 struct ext4_xattr_ibody_header *header; 465 struct ext4_inode *raw_inode; 466 struct ext4_iloc iloc; 467 void *end; 468 int error; 469 470 if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR)) 471 return 0; 472 error = ext4_get_inode_loc(inode, &iloc); 473 if (error) 474 return error; 475 raw_inode = ext4_raw_inode(&iloc); 476 header = IHDR(inode, raw_inode); 477 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 478 error = ext4_xattr_check_names(IFIRST(header), end, IFIRST(header)); 479 if (error) 480 goto cleanup; 481 error = ext4_xattr_list_entries(dentry, IFIRST(header), 482 buffer, buffer_size); 483 484cleanup: 485 brelse(iloc.bh); 486 return error; 487} 488 489/* 490 * ext4_xattr_list() 491 * 492 * Copy a list of attribute names into the buffer 493 * provided, or compute the buffer size required. 494 * Buffer is NULL to compute the size of the buffer required. 495 * 496 * Returns a negative error number on failure, or the number of bytes 497 * used / required on success. 498 */ 499static int 500ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size) 501{ 502 int ret, ret2; 503 504 down_read(&EXT4_I(d_inode(dentry))->xattr_sem); 505 ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size); 506 if (ret < 0) 507 goto errout; 508 if (buffer) { 509 buffer += ret; 510 buffer_size -= ret; 511 } 512 ret = ext4_xattr_block_list(dentry, buffer, buffer_size); 513 if (ret < 0) 514 goto errout; 515 ret += ret2; 516errout: 517 up_read(&EXT4_I(d_inode(dentry))->xattr_sem); 518 return ret; 519} 520 521/* 522 * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is 523 * not set, set it. 524 */ 525static void ext4_xattr_update_super_block(handle_t *handle, 526 struct super_block *sb) 527{ 528 if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR)) 529 return; 530 531 BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access"); 532 if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) { 533 EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR); 534 ext4_handle_dirty_super(handle, sb); 535 } 536} 537 538/* 539 * Release the xattr block BH: If the reference count is > 1, decrement it; 540 * otherwise free the block. 541 */ 542static void 543ext4_xattr_release_block(handle_t *handle, struct inode *inode, 544 struct buffer_head *bh) 545{ 546 struct mb_cache_entry *ce = NULL; 547 int error = 0; 548 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 549 550 ce = mb_cache_entry_get(ext4_mb_cache, bh->b_bdev, bh->b_blocknr); 551 BUFFER_TRACE(bh, "get_write_access"); 552 error = ext4_journal_get_write_access(handle, bh); 553 if (error) 554 goto out; 555 556 lock_buffer(bh); 557 if (BHDR(bh)->h_refcount == cpu_to_le32(1)) { 558 ea_bdebug(bh, "refcount now=0; freeing"); 559 if (ce) 560 mb_cache_entry_free(ce); 561 get_bh(bh); 562 unlock_buffer(bh); 563 ext4_free_blocks(handle, inode, bh, 0, 1, 564 EXT4_FREE_BLOCKS_METADATA | 565 EXT4_FREE_BLOCKS_FORGET); 566 } else { 567 le32_add_cpu(&BHDR(bh)->h_refcount, -1); 568 if (ce) 569 mb_cache_entry_release(ce); 570 /* 571 * Beware of this ugliness: Releasing of xattr block references 572 * from different inodes can race and so we have to protect 573 * from a race where someone else frees the block (and releases 574 * its journal_head) before we are done dirtying the buffer. In 575 * nojournal mode this race is harmless and we actually cannot 576 * call ext4_handle_dirty_xattr_block() with locked buffer as 577 * that function can call sync_dirty_buffer() so for that case 578 * we handle the dirtying after unlocking the buffer. 579 */ 580 if (ext4_handle_valid(handle)) 581 error = ext4_handle_dirty_xattr_block(handle, inode, 582 bh); 583 unlock_buffer(bh); 584 if (!ext4_handle_valid(handle)) 585 error = ext4_handle_dirty_xattr_block(handle, inode, 586 bh); 587 if (IS_SYNC(inode)) 588 ext4_handle_sync(handle); 589 dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1)); 590 ea_bdebug(bh, "refcount now=%d; releasing", 591 le32_to_cpu(BHDR(bh)->h_refcount)); 592 } 593out: 594 ext4_std_error(inode->i_sb, error); 595 return; 596} 597 598/* 599 * Find the available free space for EAs. This also returns the total number of 600 * bytes used by EA entries. 601 */ 602static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last, 603 size_t *min_offs, void *base, int *total) 604{ 605 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 606 if (!last->e_value_block && last->e_value_size) { 607 size_t offs = le16_to_cpu(last->e_value_offs); 608 if (offs < *min_offs) 609 *min_offs = offs; 610 } 611 if (total) 612 *total += EXT4_XATTR_LEN(last->e_name_len); 613 } 614 return (*min_offs - ((void *)last - base) - sizeof(__u32)); 615} 616 617static int 618ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s) 619{ 620 struct ext4_xattr_entry *last; 621 size_t free, min_offs = s->end - s->base, name_len = strlen(i->name); 622 623 /* Compute min_offs and last. */ 624 last = s->first; 625 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 626 if (!last->e_value_block && last->e_value_size) { 627 size_t offs = le16_to_cpu(last->e_value_offs); 628 if (offs < min_offs) 629 min_offs = offs; 630 } 631 } 632 free = min_offs - ((void *)last - s->base) - sizeof(__u32); 633 if (!s->not_found) { 634 if (!s->here->e_value_block && s->here->e_value_size) { 635 size_t size = le32_to_cpu(s->here->e_value_size); 636 free += EXT4_XATTR_SIZE(size); 637 } 638 free += EXT4_XATTR_LEN(name_len); 639 } 640 if (i->value) { 641 if (free < EXT4_XATTR_LEN(name_len) + 642 EXT4_XATTR_SIZE(i->value_len)) 643 return -ENOSPC; 644 } 645 646 if (i->value && s->not_found) { 647 /* Insert the new name. */ 648 size_t size = EXT4_XATTR_LEN(name_len); 649 size_t rest = (void *)last - (void *)s->here + sizeof(__u32); 650 memmove((void *)s->here + size, s->here, rest); 651 memset(s->here, 0, size); 652 s->here->e_name_index = i->name_index; 653 s->here->e_name_len = name_len; 654 memcpy(s->here->e_name, i->name, name_len); 655 } else { 656 if (!s->here->e_value_block && s->here->e_value_size) { 657 void *first_val = s->base + min_offs; 658 size_t offs = le16_to_cpu(s->here->e_value_offs); 659 void *val = s->base + offs; 660 size_t size = EXT4_XATTR_SIZE( 661 le32_to_cpu(s->here->e_value_size)); 662 663 if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) { 664 /* The old and the new value have the same 665 size. Just replace. */ 666 s->here->e_value_size = 667 cpu_to_le32(i->value_len); 668 if (i->value == EXT4_ZERO_XATTR_VALUE) { 669 memset(val, 0, size); 670 } else { 671 /* Clear pad bytes first. */ 672 memset(val + size - EXT4_XATTR_PAD, 0, 673 EXT4_XATTR_PAD); 674 memcpy(val, i->value, i->value_len); 675 } 676 return 0; 677 } 678 679 /* Remove the old value. */ 680 memmove(first_val + size, first_val, val - first_val); 681 memset(first_val, 0, size); 682 s->here->e_value_size = 0; 683 s->here->e_value_offs = 0; 684 min_offs += size; 685 686 /* Adjust all value offsets. */ 687 last = s->first; 688 while (!IS_LAST_ENTRY(last)) { 689 size_t o = le16_to_cpu(last->e_value_offs); 690 if (!last->e_value_block && 691 last->e_value_size && o < offs) 692 last->e_value_offs = 693 cpu_to_le16(o + size); 694 last = EXT4_XATTR_NEXT(last); 695 } 696 } 697 if (!i->value) { 698 /* Remove the old name. */ 699 size_t size = EXT4_XATTR_LEN(name_len); 700 last = ENTRY((void *)last - size); 701 memmove(s->here, (void *)s->here + size, 702 (void *)last - (void *)s->here + sizeof(__u32)); 703 memset(last, 0, size); 704 } 705 } 706 707 if (i->value) { 708 /* Insert the new value. */ 709 s->here->e_value_size = cpu_to_le32(i->value_len); 710 if (i->value_len) { 711 size_t size = EXT4_XATTR_SIZE(i->value_len); 712 void *val = s->base + min_offs - size; 713 s->here->e_value_offs = cpu_to_le16(min_offs - size); 714 if (i->value == EXT4_ZERO_XATTR_VALUE) { 715 memset(val, 0, size); 716 } else { 717 /* Clear the pad bytes first. */ 718 memset(val + size - EXT4_XATTR_PAD, 0, 719 EXT4_XATTR_PAD); 720 memcpy(val, i->value, i->value_len); 721 } 722 } 723 } 724 return 0; 725} 726 727struct ext4_xattr_block_find { 728 struct ext4_xattr_search s; 729 struct buffer_head *bh; 730}; 731 732static int 733ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i, 734 struct ext4_xattr_block_find *bs) 735{ 736 struct super_block *sb = inode->i_sb; 737 int error; 738 739 ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", 740 i->name_index, i->name, i->value, (long)i->value_len); 741 742 if (EXT4_I(inode)->i_file_acl) { 743 /* The inode already has an extended attribute block. */ 744 bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl); 745 error = -EIO; 746 if (!bs->bh) 747 goto cleanup; 748 ea_bdebug(bs->bh, "b_count=%d, refcount=%d", 749 atomic_read(&(bs->bh->b_count)), 750 le32_to_cpu(BHDR(bs->bh)->h_refcount)); 751 if (ext4_xattr_check_block(inode, bs->bh)) { 752 EXT4_ERROR_INODE(inode, "bad block %llu", 753 EXT4_I(inode)->i_file_acl); 754 error = -EIO; 755 goto cleanup; 756 } 757 /* Find the named attribute. */ 758 bs->s.base = BHDR(bs->bh); 759 bs->s.first = BFIRST(bs->bh); 760 bs->s.end = bs->bh->b_data + bs->bh->b_size; 761 bs->s.here = bs->s.first; 762 error = ext4_xattr_find_entry(&bs->s.here, i->name_index, 763 i->name, bs->bh->b_size, 1); 764 if (error && error != -ENODATA) 765 goto cleanup; 766 bs->s.not_found = error; 767 } 768 error = 0; 769 770cleanup: 771 return error; 772} 773 774static int 775ext4_xattr_block_set(handle_t *handle, struct inode *inode, 776 struct ext4_xattr_info *i, 777 struct ext4_xattr_block_find *bs) 778{ 779 struct super_block *sb = inode->i_sb; 780 struct buffer_head *new_bh = NULL; 781 struct ext4_xattr_search *s = &bs->s; 782 struct mb_cache_entry *ce = NULL; 783 int error = 0; 784 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 785 786#define header(x) ((struct ext4_xattr_header *)(x)) 787 788 if (i->value && i->value_len > sb->s_blocksize) 789 return -ENOSPC; 790 if (s->base) { 791 ce = mb_cache_entry_get(ext4_mb_cache, bs->bh->b_bdev, 792 bs->bh->b_blocknr); 793 BUFFER_TRACE(bs->bh, "get_write_access"); 794 error = ext4_journal_get_write_access(handle, bs->bh); 795 if (error) 796 goto cleanup; 797 lock_buffer(bs->bh); 798 799 if (header(s->base)->h_refcount == cpu_to_le32(1)) { 800 if (ce) { 801 mb_cache_entry_free(ce); 802 ce = NULL; 803 } 804 ea_bdebug(bs->bh, "modifying in-place"); 805 error = ext4_xattr_set_entry(i, s); 806 if (!error) { 807 if (!IS_LAST_ENTRY(s->first)) 808 ext4_xattr_rehash(header(s->base), 809 s->here); 810 ext4_xattr_cache_insert(ext4_mb_cache, 811 bs->bh); 812 } 813 unlock_buffer(bs->bh); 814 if (error == -EIO) 815 goto bad_block; 816 if (!error) 817 error = ext4_handle_dirty_xattr_block(handle, 818 inode, 819 bs->bh); 820 if (error) 821 goto cleanup; 822 goto inserted; 823 } else { 824 int offset = (char *)s->here - bs->bh->b_data; 825 826 unlock_buffer(bs->bh); 827 if (ce) { 828 mb_cache_entry_release(ce); 829 ce = NULL; 830 } 831 ea_bdebug(bs->bh, "cloning"); 832 s->base = kmalloc(bs->bh->b_size, GFP_NOFS); 833 error = -ENOMEM; 834 if (s->base == NULL) 835 goto cleanup; 836 memcpy(s->base, BHDR(bs->bh), bs->bh->b_size); 837 s->first = ENTRY(header(s->base)+1); 838 header(s->base)->h_refcount = cpu_to_le32(1); 839 s->here = ENTRY(s->base + offset); 840 s->end = s->base + bs->bh->b_size; 841 } 842 } else { 843 /* Allocate a buffer where we construct the new block. */ 844 s->base = kzalloc(sb->s_blocksize, GFP_NOFS); 845 /* assert(header == s->base) */ 846 error = -ENOMEM; 847 if (s->base == NULL) 848 goto cleanup; 849 header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 850 header(s->base)->h_blocks = cpu_to_le32(1); 851 header(s->base)->h_refcount = cpu_to_le32(1); 852 s->first = ENTRY(header(s->base)+1); 853 s->here = ENTRY(header(s->base)+1); 854 s->end = s->base + sb->s_blocksize; 855 } 856 857 error = ext4_xattr_set_entry(i, s); 858 if (error == -EIO) 859 goto bad_block; 860 if (error) 861 goto cleanup; 862 if (!IS_LAST_ENTRY(s->first)) 863 ext4_xattr_rehash(header(s->base), s->here); 864 865inserted: 866 if (!IS_LAST_ENTRY(s->first)) { 867 new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce); 868 if (new_bh) { 869 /* We found an identical block in the cache. */ 870 if (new_bh == bs->bh) 871 ea_bdebug(new_bh, "keeping"); 872 else { 873 /* The old block is released after updating 874 the inode. */ 875 error = dquot_alloc_block(inode, 876 EXT4_C2B(EXT4_SB(sb), 1)); 877 if (error) 878 goto cleanup; 879 BUFFER_TRACE(new_bh, "get_write_access"); 880 error = ext4_journal_get_write_access(handle, 881 new_bh); 882 if (error) 883 goto cleanup_dquot; 884 lock_buffer(new_bh); 885 le32_add_cpu(&BHDR(new_bh)->h_refcount, 1); 886 ea_bdebug(new_bh, "reusing; refcount now=%d", 887 le32_to_cpu(BHDR(new_bh)->h_refcount)); 888 unlock_buffer(new_bh); 889 error = ext4_handle_dirty_xattr_block(handle, 890 inode, 891 new_bh); 892 if (error) 893 goto cleanup_dquot; 894 } 895 mb_cache_entry_release(ce); 896 ce = NULL; 897 } else if (bs->bh && s->base == bs->bh->b_data) { 898 /* We were modifying this block in-place. */ 899 ea_bdebug(bs->bh, "keeping this block"); 900 new_bh = bs->bh; 901 get_bh(new_bh); 902 } else { 903 /* We need to allocate a new block */ 904 ext4_fsblk_t goal, block; 905 906 goal = ext4_group_first_block_no(sb, 907 EXT4_I(inode)->i_block_group); 908 909 /* non-extent files can't have physical blocks past 2^32 */ 910 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 911 goal = goal & EXT4_MAX_BLOCK_FILE_PHYS; 912 913 block = ext4_new_meta_blocks(handle, inode, goal, 0, 914 NULL, &error); 915 if (error) 916 goto cleanup; 917 918 if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) 919 BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS); 920 921 ea_idebug(inode, "creating block %llu", 922 (unsigned long long)block); 923 924 new_bh = sb_getblk(sb, block); 925 if (unlikely(!new_bh)) { 926 error = -ENOMEM; 927getblk_failed: 928 ext4_free_blocks(handle, inode, NULL, block, 1, 929 EXT4_FREE_BLOCKS_METADATA); 930 goto cleanup; 931 } 932 lock_buffer(new_bh); 933 error = ext4_journal_get_create_access(handle, new_bh); 934 if (error) { 935 unlock_buffer(new_bh); 936 error = -EIO; 937 goto getblk_failed; 938 } 939 memcpy(new_bh->b_data, s->base, new_bh->b_size); 940 set_buffer_uptodate(new_bh); 941 unlock_buffer(new_bh); 942 ext4_xattr_cache_insert(ext4_mb_cache, new_bh); 943 error = ext4_handle_dirty_xattr_block(handle, 944 inode, new_bh); 945 if (error) 946 goto cleanup; 947 } 948 } 949 950 /* Update the inode. */ 951 EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; 952 953 /* Drop the previous xattr block. */ 954 if (bs->bh && bs->bh != new_bh) 955 ext4_xattr_release_block(handle, inode, bs->bh); 956 error = 0; 957 958cleanup: 959 if (ce) 960 mb_cache_entry_release(ce); 961 brelse(new_bh); 962 if (!(bs->bh && s->base == bs->bh->b_data)) 963 kfree(s->base); 964 965 return error; 966 967cleanup_dquot: 968 dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1)); 969 goto cleanup; 970 971bad_block: 972 EXT4_ERROR_INODE(inode, "bad block %llu", 973 EXT4_I(inode)->i_file_acl); 974 goto cleanup; 975 976#undef header 977} 978 979int ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, 980 struct ext4_xattr_ibody_find *is) 981{ 982 struct ext4_xattr_ibody_header *header; 983 struct ext4_inode *raw_inode; 984 int error; 985 986 if (EXT4_I(inode)->i_extra_isize == 0) 987 return 0; 988 raw_inode = ext4_raw_inode(&is->iloc); 989 header = IHDR(inode, raw_inode); 990 is->s.base = is->s.first = IFIRST(header); 991 is->s.here = is->s.first; 992 is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 993 if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { 994 error = ext4_xattr_check_names(IFIRST(header), is->s.end, 995 IFIRST(header)); 996 if (error) 997 return error; 998 /* Find the named attribute. */ 999 error = ext4_xattr_find_entry(&is->s.here, i->name_index, 1000 i->name, is->s.end - 1001 (void *)is->s.base, 0); 1002 if (error && error != -ENODATA) 1003 return error; 1004 is->s.not_found = error; 1005 } 1006 return 0; 1007} 1008 1009int ext4_xattr_ibody_inline_set(handle_t *handle, struct inode *inode, 1010 struct ext4_xattr_info *i, 1011 struct ext4_xattr_ibody_find *is) 1012{ 1013 struct ext4_xattr_ibody_header *header; 1014 struct ext4_xattr_search *s = &is->s; 1015 int error; 1016 1017 if (EXT4_I(inode)->i_extra_isize == 0) 1018 return -ENOSPC; 1019 error = ext4_xattr_set_entry(i, s); 1020 if (error) { 1021 if (error == -ENOSPC && 1022 ext4_has_inline_data(inode)) { 1023 error = ext4_try_to_evict_inline_data(handle, inode, 1024 EXT4_XATTR_LEN(strlen(i->name) + 1025 EXT4_XATTR_SIZE(i->value_len))); 1026 if (error) 1027 return error; 1028 error = ext4_xattr_ibody_find(inode, i, is); 1029 if (error) 1030 return error; 1031 error = ext4_xattr_set_entry(i, s); 1032 } 1033 if (error) 1034 return error; 1035 } 1036 header = IHDR(inode, ext4_raw_inode(&is->iloc)); 1037 if (!IS_LAST_ENTRY(s->first)) { 1038 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 1039 ext4_set_inode_state(inode, EXT4_STATE_XATTR); 1040 } else { 1041 header->h_magic = cpu_to_le32(0); 1042 ext4_clear_inode_state(inode, EXT4_STATE_XATTR); 1043 } 1044 return 0; 1045} 1046 1047static int ext4_xattr_ibody_set(handle_t *handle, struct inode *inode, 1048 struct ext4_xattr_info *i, 1049 struct ext4_xattr_ibody_find *is) 1050{ 1051 struct ext4_xattr_ibody_header *header; 1052 struct ext4_xattr_search *s = &is->s; 1053 int error; 1054 1055 if (EXT4_I(inode)->i_extra_isize == 0) 1056 return -ENOSPC; 1057 error = ext4_xattr_set_entry(i, s); 1058 if (error) 1059 return error; 1060 header = IHDR(inode, ext4_raw_inode(&is->iloc)); 1061 if (!IS_LAST_ENTRY(s->first)) { 1062 header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); 1063 ext4_set_inode_state(inode, EXT4_STATE_XATTR); 1064 } else { 1065 header->h_magic = cpu_to_le32(0); 1066 ext4_clear_inode_state(inode, EXT4_STATE_XATTR); 1067 } 1068 return 0; 1069} 1070 1071/* 1072 * ext4_xattr_set_handle() 1073 * 1074 * Create, replace or remove an extended attribute for this inode. Value 1075 * is NULL to remove an existing extended attribute, and non-NULL to 1076 * either replace an existing extended attribute, or create a new extended 1077 * attribute. The flags XATTR_REPLACE and XATTR_CREATE 1078 * specify that an extended attribute must exist and must not exist 1079 * previous to the call, respectively. 1080 * 1081 * Returns 0, or a negative error number on failure. 1082 */ 1083int 1084ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, 1085 const char *name, const void *value, size_t value_len, 1086 int flags) 1087{ 1088 struct ext4_xattr_info i = { 1089 .name_index = name_index, 1090 .name = name, 1091 .value = value, 1092 .value_len = value_len, 1093 1094 }; 1095 struct ext4_xattr_ibody_find is = { 1096 .s = { .not_found = -ENODATA, }, 1097 }; 1098 struct ext4_xattr_block_find bs = { 1099 .s = { .not_found = -ENODATA, }, 1100 }; 1101 unsigned long no_expand; 1102 int error; 1103 1104 if (!name) 1105 return -EINVAL; 1106 if (strlen(name) > 255) 1107 return -ERANGE; 1108 down_write(&EXT4_I(inode)->xattr_sem); 1109 no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND); 1110 ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); 1111 1112 error = ext4_reserve_inode_write(handle, inode, &is.iloc); 1113 if (error) 1114 goto cleanup; 1115 1116 if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) { 1117 struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc); 1118 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); 1119 ext4_clear_inode_state(inode, EXT4_STATE_NEW); 1120 } 1121 1122 error = ext4_xattr_ibody_find(inode, &i, &is); 1123 if (error) 1124 goto cleanup; 1125 if (is.s.not_found) 1126 error = ext4_xattr_block_find(inode, &i, &bs); 1127 if (error) 1128 goto cleanup; 1129 if (is.s.not_found && bs.s.not_found) { 1130 error = -ENODATA; 1131 if (flags & XATTR_REPLACE) 1132 goto cleanup; 1133 error = 0; 1134 if (!value) 1135 goto cleanup; 1136 } else { 1137 error = -EEXIST; 1138 if (flags & XATTR_CREATE) 1139 goto cleanup; 1140 } 1141 if (!value) { 1142 if (!is.s.not_found) 1143 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1144 else if (!bs.s.not_found) 1145 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1146 } else { 1147 error = ext4_xattr_ibody_set(handle, inode, &i, &is); 1148 if (!error && !bs.s.not_found) { 1149 i.value = NULL; 1150 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1151 } else if (error == -ENOSPC) { 1152 if (EXT4_I(inode)->i_file_acl && !bs.s.base) { 1153 error = ext4_xattr_block_find(inode, &i, &bs); 1154 if (error) 1155 goto cleanup; 1156 } 1157 error = ext4_xattr_block_set(handle, inode, &i, &bs); 1158 if (error) 1159 goto cleanup; 1160 if (!is.s.not_found) { 1161 i.value = NULL; 1162 error = ext4_xattr_ibody_set(handle, inode, &i, 1163 &is); 1164 } 1165 } 1166 } 1167 if (!error) { 1168 ext4_xattr_update_super_block(handle, inode->i_sb); 1169 inode->i_ctime = ext4_current_time(inode); 1170 if (!value) 1171 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); 1172 error = ext4_mark_iloc_dirty(handle, inode, &is.iloc); 1173 /* 1174 * The bh is consumed by ext4_mark_iloc_dirty, even with 1175 * error != 0. 1176 */ 1177 is.iloc.bh = NULL; 1178 if (IS_SYNC(inode)) 1179 ext4_handle_sync(handle); 1180 } 1181 1182cleanup: 1183 brelse(is.iloc.bh); 1184 brelse(bs.bh); 1185 if (no_expand == 0) 1186 ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); 1187 up_write(&EXT4_I(inode)->xattr_sem); 1188 return error; 1189} 1190 1191/* 1192 * ext4_xattr_set() 1193 * 1194 * Like ext4_xattr_set_handle, but start from an inode. This extended 1195 * attribute modification is a filesystem transaction by itself. 1196 * 1197 * Returns 0, or a negative error number on failure. 1198 */ 1199int 1200ext4_xattr_set(struct inode *inode, int name_index, const char *name, 1201 const void *value, size_t value_len, int flags) 1202{ 1203 handle_t *handle; 1204 int error, retries = 0; 1205 int credits = ext4_jbd2_credits_xattr(inode); 1206 1207retry: 1208 handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits); 1209 if (IS_ERR(handle)) { 1210 error = PTR_ERR(handle); 1211 } else { 1212 int error2; 1213 1214 error = ext4_xattr_set_handle(handle, inode, name_index, name, 1215 value, value_len, flags); 1216 error2 = ext4_journal_stop(handle); 1217 if (error == -ENOSPC && 1218 ext4_should_retry_alloc(inode->i_sb, &retries)) 1219 goto retry; 1220 if (error == 0) 1221 error = error2; 1222 } 1223 1224 return error; 1225} 1226 1227/* 1228 * Shift the EA entries in the inode to create space for the increased 1229 * i_extra_isize. 1230 */ 1231static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry, 1232 int value_offs_shift, void *to, 1233 void *from, size_t n, int blocksize) 1234{ 1235 struct ext4_xattr_entry *last = entry; 1236 int new_offs; 1237 1238 /* Adjust the value offsets of the entries */ 1239 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1240 if (!last->e_value_block && last->e_value_size) { 1241 new_offs = le16_to_cpu(last->e_value_offs) + 1242 value_offs_shift; 1243 BUG_ON(new_offs + le32_to_cpu(last->e_value_size) 1244 > blocksize); 1245 last->e_value_offs = cpu_to_le16(new_offs); 1246 } 1247 } 1248 /* Shift the entries by n bytes */ 1249 memmove(to, from, n); 1250} 1251 1252/* 1253 * Expand an inode by new_extra_isize bytes when EAs are present. 1254 * Returns 0 on success or negative error number on failure. 1255 */ 1256int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, 1257 struct ext4_inode *raw_inode, handle_t *handle) 1258{ 1259 struct ext4_xattr_ibody_header *header; 1260 struct ext4_xattr_entry *entry, *last, *first; 1261 struct buffer_head *bh = NULL; 1262 struct ext4_xattr_ibody_find *is = NULL; 1263 struct ext4_xattr_block_find *bs = NULL; 1264 char *buffer = NULL, *b_entry_name = NULL; 1265 size_t min_offs, free; 1266 int total_ino; 1267 void *base, *start, *end; 1268 int extra_isize = 0, error = 0, tried_min_extra_isize = 0; 1269 int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize); 1270 1271 down_write(&EXT4_I(inode)->xattr_sem); 1272retry: 1273 if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) { 1274 up_write(&EXT4_I(inode)->xattr_sem); 1275 return 0; 1276 } 1277 1278 header = IHDR(inode, raw_inode); 1279 entry = IFIRST(header); 1280 1281 /* 1282 * Check if enough free space is available in the inode to shift the 1283 * entries ahead by new_extra_isize. 1284 */ 1285 1286 base = start = entry; 1287 end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; 1288 min_offs = end - base; 1289 last = entry; 1290 total_ino = sizeof(struct ext4_xattr_ibody_header); 1291 1292 free = ext4_xattr_free_space(last, &min_offs, base, &total_ino); 1293 if (free >= new_extra_isize) { 1294 entry = IFIRST(header); 1295 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize 1296 - new_extra_isize, (void *)raw_inode + 1297 EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize, 1298 (void *)header, total_ino, 1299 inode->i_sb->s_blocksize); 1300 EXT4_I(inode)->i_extra_isize = new_extra_isize; 1301 error = 0; 1302 goto cleanup; 1303 } 1304 1305 /* 1306 * Enough free space isn't available in the inode, check if 1307 * EA block can hold new_extra_isize bytes. 1308 */ 1309 if (EXT4_I(inode)->i_file_acl) { 1310 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1311 error = -EIO; 1312 if (!bh) 1313 goto cleanup; 1314 if (ext4_xattr_check_block(inode, bh)) { 1315 EXT4_ERROR_INODE(inode, "bad block %llu", 1316 EXT4_I(inode)->i_file_acl); 1317 error = -EIO; 1318 goto cleanup; 1319 } 1320 base = BHDR(bh); 1321 first = BFIRST(bh); 1322 end = bh->b_data + bh->b_size; 1323 min_offs = end - base; 1324 free = ext4_xattr_free_space(first, &min_offs, base, NULL); 1325 if (free < new_extra_isize) { 1326 if (!tried_min_extra_isize && s_min_extra_isize) { 1327 tried_min_extra_isize++; 1328 new_extra_isize = s_min_extra_isize; 1329 brelse(bh); 1330 goto retry; 1331 } 1332 error = -1; 1333 goto cleanup; 1334 } 1335 } else { 1336 free = inode->i_sb->s_blocksize; 1337 } 1338 1339 while (new_extra_isize > 0) { 1340 size_t offs, size, entry_size; 1341 struct ext4_xattr_entry *small_entry = NULL; 1342 struct ext4_xattr_info i = { 1343 .value = NULL, 1344 .value_len = 0, 1345 }; 1346 unsigned int total_size; /* EA entry size + value size */ 1347 unsigned int shift_bytes; /* No. of bytes to shift EAs by? */ 1348 unsigned int min_total_size = ~0U; 1349 1350 is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS); 1351 bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS); 1352 if (!is || !bs) { 1353 error = -ENOMEM; 1354 goto cleanup; 1355 } 1356 1357 is->s.not_found = -ENODATA; 1358 bs->s.not_found = -ENODATA; 1359 is->iloc.bh = NULL; 1360 bs->bh = NULL; 1361 1362 last = IFIRST(header); 1363 /* Find the entry best suited to be pushed into EA block */ 1364 entry = NULL; 1365 for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { 1366 total_size = 1367 EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) + 1368 EXT4_XATTR_LEN(last->e_name_len); 1369 if (total_size <= free && total_size < min_total_size) { 1370 if (total_size < new_extra_isize) { 1371 small_entry = last; 1372 } else { 1373 entry = last; 1374 min_total_size = total_size; 1375 } 1376 } 1377 } 1378 1379 if (entry == NULL) { 1380 if (small_entry) { 1381 entry = small_entry; 1382 } else { 1383 if (!tried_min_extra_isize && 1384 s_min_extra_isize) { 1385 tried_min_extra_isize++; 1386 new_extra_isize = s_min_extra_isize; 1387 kfree(is); is = NULL; 1388 kfree(bs); bs = NULL; 1389 brelse(bh); 1390 goto retry; 1391 } 1392 error = -1; 1393 goto cleanup; 1394 } 1395 } 1396 offs = le16_to_cpu(entry->e_value_offs); 1397 size = le32_to_cpu(entry->e_value_size); 1398 entry_size = EXT4_XATTR_LEN(entry->e_name_len); 1399 i.name_index = entry->e_name_index, 1400 buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS); 1401 b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS); 1402 if (!buffer || !b_entry_name) { 1403 error = -ENOMEM; 1404 goto cleanup; 1405 } 1406 /* Save the entry name and the entry value */ 1407 memcpy(buffer, (void *)IFIRST(header) + offs, 1408 EXT4_XATTR_SIZE(size)); 1409 memcpy(b_entry_name, entry->e_name, entry->e_name_len); 1410 b_entry_name[entry->e_name_len] = '\0'; 1411 i.name = b_entry_name; 1412 1413 error = ext4_get_inode_loc(inode, &is->iloc); 1414 if (error) 1415 goto cleanup; 1416 1417 error = ext4_xattr_ibody_find(inode, &i, is); 1418 if (error) 1419 goto cleanup; 1420 1421 /* Remove the chosen entry from the inode */ 1422 error = ext4_xattr_ibody_set(handle, inode, &i, is); 1423 if (error) 1424 goto cleanup; 1425 1426 entry = IFIRST(header); 1427 if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize) 1428 shift_bytes = new_extra_isize; 1429 else 1430 shift_bytes = entry_size + size; 1431 /* Adjust the offsets and shift the remaining entries ahead */ 1432 ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize - 1433 shift_bytes, (void *)raw_inode + 1434 EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes, 1435 (void *)header, total_ino - entry_size, 1436 inode->i_sb->s_blocksize); 1437 1438 extra_isize += shift_bytes; 1439 new_extra_isize -= shift_bytes; 1440 EXT4_I(inode)->i_extra_isize = extra_isize; 1441 1442 i.name = b_entry_name; 1443 i.value = buffer; 1444 i.value_len = size; 1445 error = ext4_xattr_block_find(inode, &i, bs); 1446 if (error) 1447 goto cleanup; 1448 1449 /* Add entry which was removed from the inode into the block */ 1450 error = ext4_xattr_block_set(handle, inode, &i, bs); 1451 if (error) 1452 goto cleanup; 1453 kfree(b_entry_name); 1454 kfree(buffer); 1455 b_entry_name = NULL; 1456 buffer = NULL; 1457 brelse(is->iloc.bh); 1458 kfree(is); 1459 kfree(bs); 1460 } 1461 brelse(bh); 1462 up_write(&EXT4_I(inode)->xattr_sem); 1463 return 0; 1464 1465cleanup: 1466 kfree(b_entry_name); 1467 kfree(buffer); 1468 if (is) 1469 brelse(is->iloc.bh); 1470 kfree(is); 1471 kfree(bs); 1472 brelse(bh); 1473 up_write(&EXT4_I(inode)->xattr_sem); 1474 return error; 1475} 1476 1477 1478 1479/* 1480 * ext4_xattr_delete_inode() 1481 * 1482 * Free extended attribute resources associated with this inode. This 1483 * is called immediately before an inode is freed. We have exclusive 1484 * access to the inode. 1485 */ 1486void 1487ext4_xattr_delete_inode(handle_t *handle, struct inode *inode) 1488{ 1489 struct buffer_head *bh = NULL; 1490 1491 if (!EXT4_I(inode)->i_file_acl) 1492 goto cleanup; 1493 bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); 1494 if (!bh) { 1495 EXT4_ERROR_INODE(inode, "block %llu read error", 1496 EXT4_I(inode)->i_file_acl); 1497 goto cleanup; 1498 } 1499 if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || 1500 BHDR(bh)->h_blocks != cpu_to_le32(1)) { 1501 EXT4_ERROR_INODE(inode, "bad block %llu", 1502 EXT4_I(inode)->i_file_acl); 1503 goto cleanup; 1504 } 1505 ext4_xattr_release_block(handle, inode, bh); 1506 EXT4_I(inode)->i_file_acl = 0; 1507 1508cleanup: 1509 brelse(bh); 1510} 1511 1512/* 1513 * ext4_xattr_put_super() 1514 * 1515 * This is called when a file system is unmounted. 1516 */ 1517void 1518ext4_xattr_put_super(struct super_block *sb) 1519{ 1520 mb_cache_shrink(sb->s_bdev); 1521} 1522 1523/* 1524 * ext4_xattr_cache_insert() 1525 * 1526 * Create a new entry in the extended attribute cache, and insert 1527 * it unless such an entry is already in the cache. 1528 * 1529 * Returns 0, or a negative error number on failure. 1530 */ 1531static void 1532ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh) 1533{ 1534 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash); 1535 struct mb_cache_entry *ce; 1536 int error; 1537 1538 ce = mb_cache_entry_alloc(ext4_mb_cache, GFP_NOFS); 1539 if (!ce) { 1540 ea_bdebug(bh, "out of memory"); 1541 return; 1542 } 1543 error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash); 1544 if (error) { 1545 mb_cache_entry_free(ce); 1546 if (error == -EBUSY) { 1547 ea_bdebug(bh, "already in cache"); 1548 error = 0; 1549 } 1550 } else { 1551 ea_bdebug(bh, "inserting [%x]", (int)hash); 1552 mb_cache_entry_release(ce); 1553 } 1554} 1555 1556/* 1557 * ext4_xattr_cmp() 1558 * 1559 * Compare two extended attribute blocks for equality. 1560 * 1561 * Returns 0 if the blocks are equal, 1 if they differ, and 1562 * a negative error number on errors. 1563 */ 1564static int 1565ext4_xattr_cmp(struct ext4_xattr_header *header1, 1566 struct ext4_xattr_header *header2) 1567{ 1568 struct ext4_xattr_entry *entry1, *entry2; 1569 1570 entry1 = ENTRY(header1+1); 1571 entry2 = ENTRY(header2+1); 1572 while (!IS_LAST_ENTRY(entry1)) { 1573 if (IS_LAST_ENTRY(entry2)) 1574 return 1; 1575 if (entry1->e_hash != entry2->e_hash || 1576 entry1->e_name_index != entry2->e_name_index || 1577 entry1->e_name_len != entry2->e_name_len || 1578 entry1->e_value_size != entry2->e_value_size || 1579 memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) 1580 return 1; 1581 if (entry1->e_value_block != 0 || entry2->e_value_block != 0) 1582 return -EIO; 1583 if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), 1584 (char *)header2 + le16_to_cpu(entry2->e_value_offs), 1585 le32_to_cpu(entry1->e_value_size))) 1586 return 1; 1587 1588 entry1 = EXT4_XATTR_NEXT(entry1); 1589 entry2 = EXT4_XATTR_NEXT(entry2); 1590 } 1591 if (!IS_LAST_ENTRY(entry2)) 1592 return 1; 1593 return 0; 1594} 1595 1596/* 1597 * ext4_xattr_cache_find() 1598 * 1599 * Find an identical extended attribute block. 1600 * 1601 * Returns a pointer to the block found, or NULL if such a block was 1602 * not found or an error occurred. 1603 */ 1604static struct buffer_head * 1605ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header, 1606 struct mb_cache_entry **pce) 1607{ 1608 __u32 hash = le32_to_cpu(header->h_hash); 1609 struct mb_cache_entry *ce; 1610 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode); 1611 1612 if (!header->h_hash) 1613 return NULL; /* never share */ 1614 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); 1615again: 1616 ce = mb_cache_entry_find_first(ext4_mb_cache, inode->i_sb->s_bdev, 1617 hash); 1618 while (ce) { 1619 struct buffer_head *bh; 1620 1621 if (IS_ERR(ce)) { 1622 if (PTR_ERR(ce) == -EAGAIN) 1623 goto again; 1624 break; 1625 } 1626 bh = sb_bread(inode->i_sb, ce->e_block); 1627 if (!bh) { 1628 EXT4_ERROR_INODE(inode, "block %lu read error", 1629 (unsigned long) ce->e_block); 1630 } else if (le32_to_cpu(BHDR(bh)->h_refcount) >= 1631 EXT4_XATTR_REFCOUNT_MAX) { 1632 ea_idebug(inode, "block %lu refcount %d>=%d", 1633 (unsigned long) ce->e_block, 1634 le32_to_cpu(BHDR(bh)->h_refcount), 1635 EXT4_XATTR_REFCOUNT_MAX); 1636 } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) { 1637 *pce = ce; 1638 return bh; 1639 } 1640 brelse(bh); 1641 ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash); 1642 } 1643 return NULL; 1644} 1645 1646#define NAME_HASH_SHIFT 5 1647#define VALUE_HASH_SHIFT 16 1648 1649/* 1650 * ext4_xattr_hash_entry() 1651 * 1652 * Compute the hash of an extended attribute. 1653 */ 1654static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header, 1655 struct ext4_xattr_entry *entry) 1656{ 1657 __u32 hash = 0; 1658 char *name = entry->e_name; 1659 int n; 1660 1661 for (n = 0; n < entry->e_name_len; n++) { 1662 hash = (hash << NAME_HASH_SHIFT) ^ 1663 (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ 1664 *name++; 1665 } 1666 1667 if (entry->e_value_block == 0 && entry->e_value_size != 0) { 1668 __le32 *value = (__le32 *)((char *)header + 1669 le16_to_cpu(entry->e_value_offs)); 1670 for (n = (le32_to_cpu(entry->e_value_size) + 1671 EXT4_XATTR_ROUND) >> EXT4_XATTR_PAD_BITS; n; n--) { 1672 hash = (hash << VALUE_HASH_SHIFT) ^ 1673 (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ 1674 le32_to_cpu(*value++); 1675 } 1676 } 1677 entry->e_hash = cpu_to_le32(hash); 1678} 1679 1680#undef NAME_HASH_SHIFT 1681#undef VALUE_HASH_SHIFT 1682 1683#define BLOCK_HASH_SHIFT 16 1684 1685/* 1686 * ext4_xattr_rehash() 1687 * 1688 * Re-compute the extended attribute hash value after an entry has changed. 1689 */ 1690static void ext4_xattr_rehash(struct ext4_xattr_header *header, 1691 struct ext4_xattr_entry *entry) 1692{ 1693 struct ext4_xattr_entry *here; 1694 __u32 hash = 0; 1695 1696 ext4_xattr_hash_entry(header, entry); 1697 here = ENTRY(header+1); 1698 while (!IS_LAST_ENTRY(here)) { 1699 if (!here->e_hash) { 1700 /* Block is not shared if an entry's hash value == 0 */ 1701 hash = 0; 1702 break; 1703 } 1704 hash = (hash << BLOCK_HASH_SHIFT) ^ 1705 (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ 1706 le32_to_cpu(here->e_hash); 1707 here = EXT4_XATTR_NEXT(here); 1708 } 1709 header->h_hash = cpu_to_le32(hash); 1710} 1711 1712#undef BLOCK_HASH_SHIFT 1713 1714#define HASH_BUCKET_BITS 10 1715 1716struct mb_cache * 1717ext4_xattr_create_cache(char *name) 1718{ 1719 return mb_cache_create(name, HASH_BUCKET_BITS); 1720} 1721 1722void ext4_xattr_destroy_cache(struct mb_cache *cache) 1723{ 1724 if (cache) 1725 mb_cache_destroy(cache); 1726} 1727 1728