1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ 2 #ifndef _BTRFS_CTREE_H_ 3 #define _BTRFS_CTREE_H_ 4 5 #include <linux/btrfs.h> 6 #include <linux/types.h> 7 #ifdef __KERNEL__ 8 #include <linux/stddef.h> 9 #else 10 #include <stddef.h> 11 #endif 12 13 /* ASCII for _BHRfS_M, no terminating nul */ 14 #define BTRFS_MAGIC 0x4D5F53665248425FULL 15 16 #define BTRFS_MAX_LEVEL 8 17 18 /* 19 * We can actually store much bigger names, but lets not confuse the rest of 20 * linux. 21 */ 22 #define BTRFS_NAME_LEN 255 23 24 /* 25 * Theoretical limit is larger, but we keep this down to a sane value. That 26 * should limit greatly the possibility of collisions on inode ref items. 27 */ 28 #define BTRFS_LINK_MAX 65535U 29 30 /* 31 * This header contains the structure definitions and constants used 32 * by file system objects that can be retrieved using 33 * the BTRFS_IOC_SEARCH_TREE ioctl. That means basically anything that 34 * is needed to describe a leaf node's key or item contents. 35 */ 36 37 /* holds pointers to all of the tree roots */ 38 #define BTRFS_ROOT_TREE_OBJECTID 1ULL 39 40 /* stores information about which extents are in use, and reference counts */ 41 #define BTRFS_EXTENT_TREE_OBJECTID 2ULL 42 43 /* 44 * chunk tree stores translations from logical -> physical block numbering 45 * the super block points to the chunk tree 46 */ 47 #define BTRFS_CHUNK_TREE_OBJECTID 3ULL 48 49 /* 50 * stores information about which areas of a given device are in use. 51 * one per device. The tree of tree roots points to the device tree 52 */ 53 #define BTRFS_DEV_TREE_OBJECTID 4ULL 54 55 /* one per subvolume, storing files and directories */ 56 #define BTRFS_FS_TREE_OBJECTID 5ULL 57 58 /* directory objectid inside the root tree */ 59 #define BTRFS_ROOT_TREE_DIR_OBJECTID 6ULL 60 61 /* holds checksums of all the data extents */ 62 #define BTRFS_CSUM_TREE_OBJECTID 7ULL 63 64 /* holds quota configuration and tracking */ 65 #define BTRFS_QUOTA_TREE_OBJECTID 8ULL 66 67 /* for storing items that use the BTRFS_UUID_KEY* types */ 68 #define BTRFS_UUID_TREE_OBJECTID 9ULL 69 70 /* tracks free space in block groups. */ 71 #define BTRFS_FREE_SPACE_TREE_OBJECTID 10ULL 72 73 /* Holds the block group items for extent tree v2. */ 74 #define BTRFS_BLOCK_GROUP_TREE_OBJECTID 11ULL 75 76 /* Tracks RAID stripes in block groups. */ 77 #define BTRFS_RAID_STRIPE_TREE_OBJECTID 12ULL 78 79 /* device stats in the device tree */ 80 #define BTRFS_DEV_STATS_OBJECTID 0ULL 81 82 /* for storing balance parameters in the root tree */ 83 #define BTRFS_BALANCE_OBJECTID -4ULL 84 85 /* orphan objectid for tracking unlinked/truncated files */ 86 #define BTRFS_ORPHAN_OBJECTID -5ULL 87 88 /* does write ahead logging to speed up fsyncs */ 89 #define BTRFS_TREE_LOG_OBJECTID -6ULL 90 #define BTRFS_TREE_LOG_FIXUP_OBJECTID -7ULL 91 92 /* for space balancing */ 93 #define BTRFS_TREE_RELOC_OBJECTID -8ULL 94 #define BTRFS_DATA_RELOC_TREE_OBJECTID -9ULL 95 96 /* 97 * extent checksums all have this objectid 98 * this allows them to share the logging tree 99 * for fsyncs 100 */ 101 #define BTRFS_EXTENT_CSUM_OBJECTID -10ULL 102 103 /* For storing free space cache */ 104 #define BTRFS_FREE_SPACE_OBJECTID -11ULL 105 106 /* 107 * The inode number assigned to the special inode for storing 108 * free ino cache 109 */ 110 #define BTRFS_FREE_INO_OBJECTID -12ULL 111 112 /* dummy objectid represents multiple objectids */ 113 #define BTRFS_MULTIPLE_OBJECTIDS -255ULL 114 115 /* 116 * All files have objectids in this range. 117 */ 118 #define BTRFS_FIRST_FREE_OBJECTID 256ULL 119 #define BTRFS_LAST_FREE_OBJECTID -256ULL 120 #define BTRFS_FIRST_CHUNK_TREE_OBJECTID 256ULL 121 122 123 /* 124 * the device items go into the chunk tree. The key is in the form 125 * [ 1 BTRFS_DEV_ITEM_KEY device_id ] 126 */ 127 #define BTRFS_DEV_ITEMS_OBJECTID 1ULL 128 129 #define BTRFS_BTREE_INODE_OBJECTID 1 130 131 #define BTRFS_EMPTY_SUBVOL_DIR_OBJECTID 2 132 133 #define BTRFS_DEV_REPLACE_DEVID 0ULL 134 135 /* 136 * inode items have the data typically returned from stat and store other 137 * info about object characteristics. There is one for every file and dir in 138 * the FS 139 */ 140 #define BTRFS_INODE_ITEM_KEY 1 141 #define BTRFS_INODE_REF_KEY 12 142 #define BTRFS_INODE_EXTREF_KEY 13 143 #define BTRFS_XATTR_ITEM_KEY 24 144 145 /* 146 * fs verity items are stored under two different key types on disk. 147 * The descriptor items: 148 * [ inode objectid, BTRFS_VERITY_DESC_ITEM_KEY, offset ] 149 * 150 * At offset 0, we store a btrfs_verity_descriptor_item which tracks the size 151 * of the descriptor item and some extra data for encryption. 152 * Starting at offset 1, these hold the generic fs verity descriptor. The 153 * latter are opaque to btrfs, we just read and write them as a blob for the 154 * higher level verity code. The most common descriptor size is 256 bytes. 155 * 156 * The merkle tree items: 157 * [ inode objectid, BTRFS_VERITY_MERKLE_ITEM_KEY, offset ] 158 * 159 * These also start at offset 0, and correspond to the merkle tree bytes. When 160 * fsverity asks for page 0 of the merkle tree, we pull up one page starting at 161 * offset 0 for this key type. These are also opaque to btrfs, we're blindly 162 * storing whatever fsverity sends down. 163 */ 164 #define BTRFS_VERITY_DESC_ITEM_KEY 36 165 #define BTRFS_VERITY_MERKLE_ITEM_KEY 37 166 167 #define BTRFS_ORPHAN_ITEM_KEY 48 168 /* reserve 2-15 close to the inode for later flexibility */ 169 170 /* 171 * dir items are the name -> inode pointers in a directory. There is one 172 * for every name in a directory. BTRFS_DIR_LOG_ITEM_KEY is no longer used 173 * but it's still defined here for documentation purposes and to help avoid 174 * having its numerical value reused in the future. 175 */ 176 #define BTRFS_DIR_LOG_ITEM_KEY 60 177 #define BTRFS_DIR_LOG_INDEX_KEY 72 178 #define BTRFS_DIR_ITEM_KEY 84 179 #define BTRFS_DIR_INDEX_KEY 96 180 /* 181 * extent data is for file data 182 */ 183 #define BTRFS_EXTENT_DATA_KEY 108 184 185 /* 186 * extent csums are stored in a separate tree and hold csums for 187 * an entire extent on disk. 188 */ 189 #define BTRFS_EXTENT_CSUM_KEY 128 190 191 /* 192 * root items point to tree roots. They are typically in the root 193 * tree used by the super block to find all the other trees 194 */ 195 #define BTRFS_ROOT_ITEM_KEY 132 196 197 /* 198 * root backrefs tie subvols and snapshots to the directory entries that 199 * reference them 200 */ 201 #define BTRFS_ROOT_BACKREF_KEY 144 202 203 /* 204 * root refs make a fast index for listing all of the snapshots and 205 * subvolumes referenced by a given root. They point directly to the 206 * directory item in the root that references the subvol 207 */ 208 #define BTRFS_ROOT_REF_KEY 156 209 210 /* 211 * extent items are in the extent map tree. These record which blocks 212 * are used, and how many references there are to each block 213 */ 214 #define BTRFS_EXTENT_ITEM_KEY 168 215 216 /* 217 * The same as the BTRFS_EXTENT_ITEM_KEY, except it's metadata we already know 218 * the length, so we save the level in key->offset instead of the length. 219 */ 220 #define BTRFS_METADATA_ITEM_KEY 169 221 222 #define BTRFS_TREE_BLOCK_REF_KEY 176 223 224 #define BTRFS_EXTENT_DATA_REF_KEY 178 225 226 /* 227 * Obsolete key. Defintion removed in 6.6, value may be reused in the future. 228 * 229 * #define BTRFS_EXTENT_REF_V0_KEY 180 230 */ 231 232 #define BTRFS_SHARED_BLOCK_REF_KEY 182 233 234 #define BTRFS_SHARED_DATA_REF_KEY 184 235 236 /* 237 * Special inline ref key which stores the id of the subvolume which originally 238 * created the extent. This subvolume owns the extent permanently from the 239 * perspective of simple quotas. Needed to know which subvolume to free quota 240 * usage from when the extent is deleted. 241 */ 242 #define BTRFS_EXTENT_OWNER_REF_KEY 188 243 244 /* 245 * block groups give us hints into the extent allocation trees. Which 246 * blocks are free etc etc 247 */ 248 #define BTRFS_BLOCK_GROUP_ITEM_KEY 192 249 250 /* 251 * Every block group is represented in the free space tree by a free space info 252 * item, which stores some accounting information. It is keyed on 253 * (block_group_start, FREE_SPACE_INFO, block_group_length). 254 */ 255 #define BTRFS_FREE_SPACE_INFO_KEY 198 256 257 /* 258 * A free space extent tracks an extent of space that is free in a block group. 259 * It is keyed on (start, FREE_SPACE_EXTENT, length). 260 */ 261 #define BTRFS_FREE_SPACE_EXTENT_KEY 199 262 263 /* 264 * When a block group becomes very fragmented, we convert it to use bitmaps 265 * instead of extents. A free space bitmap is keyed on 266 * (start, FREE_SPACE_BITMAP, length); the corresponding item is a bitmap with 267 * (length / sectorsize) bits. 268 */ 269 #define BTRFS_FREE_SPACE_BITMAP_KEY 200 270 271 #define BTRFS_DEV_EXTENT_KEY 204 272 #define BTRFS_DEV_ITEM_KEY 216 273 #define BTRFS_CHUNK_ITEM_KEY 228 274 275 #define BTRFS_RAID_STRIPE_KEY 230 276 277 /* 278 * Records the overall state of the qgroups. 279 * There's only one instance of this key present, 280 * (0, BTRFS_QGROUP_STATUS_KEY, 0) 281 */ 282 #define BTRFS_QGROUP_STATUS_KEY 240 283 /* 284 * Records the currently used space of the qgroup. 285 * One key per qgroup, (0, BTRFS_QGROUP_INFO_KEY, qgroupid). 286 */ 287 #define BTRFS_QGROUP_INFO_KEY 242 288 /* 289 * Contains the user configured limits for the qgroup. 290 * One key per qgroup, (0, BTRFS_QGROUP_LIMIT_KEY, qgroupid). 291 */ 292 #define BTRFS_QGROUP_LIMIT_KEY 244 293 /* 294 * Records the child-parent relationship of qgroups. For 295 * each relation, 2 keys are present: 296 * (childid, BTRFS_QGROUP_RELATION_KEY, parentid) 297 * (parentid, BTRFS_QGROUP_RELATION_KEY, childid) 298 */ 299 #define BTRFS_QGROUP_RELATION_KEY 246 300 301 /* 302 * Obsolete name, see BTRFS_TEMPORARY_ITEM_KEY. 303 */ 304 #define BTRFS_BALANCE_ITEM_KEY 248 305 306 /* 307 * The key type for tree items that are stored persistently, but do not need to 308 * exist for extended period of time. The items can exist in any tree. 309 * 310 * [subtype, BTRFS_TEMPORARY_ITEM_KEY, data] 311 * 312 * Existing items: 313 * 314 * - balance status item 315 * (BTRFS_BALANCE_OBJECTID, BTRFS_TEMPORARY_ITEM_KEY, 0) 316 */ 317 #define BTRFS_TEMPORARY_ITEM_KEY 248 318 319 /* 320 * Obsolete name, see BTRFS_PERSISTENT_ITEM_KEY 321 */ 322 #define BTRFS_DEV_STATS_KEY 249 323 324 /* 325 * The key type for tree items that are stored persistently and usually exist 326 * for a long period, eg. filesystem lifetime. The item kinds can be status 327 * information, stats or preference values. The item can exist in any tree. 328 * 329 * [subtype, BTRFS_PERSISTENT_ITEM_KEY, data] 330 * 331 * Existing items: 332 * 333 * - device statistics, store IO stats in the device tree, one key for all 334 * stats 335 * (BTRFS_DEV_STATS_OBJECTID, BTRFS_DEV_STATS_KEY, 0) 336 */ 337 #define BTRFS_PERSISTENT_ITEM_KEY 249 338 339 /* 340 * Persistently stores the device replace state in the device tree. 341 * The key is built like this: (0, BTRFS_DEV_REPLACE_KEY, 0). 342 */ 343 #define BTRFS_DEV_REPLACE_KEY 250 344 345 /* 346 * Stores items that allow to quickly map UUIDs to something else. 347 * These items are part of the filesystem UUID tree. 348 * The key is built like this: 349 * (UUID_upper_64_bits, BTRFS_UUID_KEY*, UUID_lower_64_bits). 350 */ 351 #if BTRFS_UUID_SIZE != 16 352 #error "UUID items require BTRFS_UUID_SIZE == 16!" 353 #endif 354 #define BTRFS_UUID_KEY_SUBVOL 251 /* for UUIDs assigned to subvols */ 355 #define BTRFS_UUID_KEY_RECEIVED_SUBVOL 252 /* for UUIDs assigned to 356 * received subvols */ 357 358 /* 359 * string items are for debugging. They just store a short string of 360 * data in the FS 361 */ 362 #define BTRFS_STRING_ITEM_KEY 253 363 364 /* Maximum metadata block size (nodesize) */ 365 #define BTRFS_MAX_METADATA_BLOCKSIZE 65536 366 367 /* 32 bytes in various csum fields */ 368 #define BTRFS_CSUM_SIZE 32 369 370 /* csum types */ 371 enum btrfs_csum_type { 372 BTRFS_CSUM_TYPE_CRC32 = 0, 373 BTRFS_CSUM_TYPE_XXHASH = 1, 374 BTRFS_CSUM_TYPE_SHA256 = 2, 375 BTRFS_CSUM_TYPE_BLAKE2 = 3, 376 }; 377 378 /* 379 * flags definitions for directory entry item type 380 * 381 * Used by: 382 * struct btrfs_dir_item.type 383 * 384 * Values 0..7 must match common file type values in fs_types.h. 385 */ 386 #define BTRFS_FT_UNKNOWN 0 387 #define BTRFS_FT_REG_FILE 1 388 #define BTRFS_FT_DIR 2 389 #define BTRFS_FT_CHRDEV 3 390 #define BTRFS_FT_BLKDEV 4 391 #define BTRFS_FT_FIFO 5 392 #define BTRFS_FT_SOCK 6 393 #define BTRFS_FT_SYMLINK 7 394 #define BTRFS_FT_XATTR 8 395 #define BTRFS_FT_MAX 9 396 /* Directory contains encrypted data */ 397 #define BTRFS_FT_ENCRYPTED 0x80 398 399 static inline __u8 btrfs_dir_flags_to_ftype(__u8 flags) 400 { 401 return flags & ~BTRFS_FT_ENCRYPTED; 402 } 403 404 /* 405 * Inode flags 406 */ 407 #define BTRFS_INODE_NODATASUM (1U << 0) 408 #define BTRFS_INODE_NODATACOW (1U << 1) 409 #define BTRFS_INODE_READONLY (1U << 2) 410 #define BTRFS_INODE_NOCOMPRESS (1U << 3) 411 #define BTRFS_INODE_PREALLOC (1U << 4) 412 #define BTRFS_INODE_SYNC (1U << 5) 413 #define BTRFS_INODE_IMMUTABLE (1U << 6) 414 #define BTRFS_INODE_APPEND (1U << 7) 415 #define BTRFS_INODE_NODUMP (1U << 8) 416 #define BTRFS_INODE_NOATIME (1U << 9) 417 #define BTRFS_INODE_DIRSYNC (1U << 10) 418 #define BTRFS_INODE_COMPRESS (1U << 11) 419 420 #define BTRFS_INODE_ROOT_ITEM_INIT (1U << 31) 421 422 #define BTRFS_INODE_FLAG_MASK \ 423 (BTRFS_INODE_NODATASUM | \ 424 BTRFS_INODE_NODATACOW | \ 425 BTRFS_INODE_READONLY | \ 426 BTRFS_INODE_NOCOMPRESS | \ 427 BTRFS_INODE_PREALLOC | \ 428 BTRFS_INODE_SYNC | \ 429 BTRFS_INODE_IMMUTABLE | \ 430 BTRFS_INODE_APPEND | \ 431 BTRFS_INODE_NODUMP | \ 432 BTRFS_INODE_NOATIME | \ 433 BTRFS_INODE_DIRSYNC | \ 434 BTRFS_INODE_COMPRESS | \ 435 BTRFS_INODE_ROOT_ITEM_INIT) 436 437 #define BTRFS_INODE_RO_VERITY (1U << 0) 438 439 #define BTRFS_INODE_RO_FLAG_MASK (BTRFS_INODE_RO_VERITY) 440 441 /* 442 * The key defines the order in the tree, and so it also defines (optimal) 443 * block layout. 444 * 445 * objectid corresponds to the inode number. 446 * 447 * type tells us things about the object, and is a kind of stream selector. 448 * so for a given inode, keys with type of 1 might refer to the inode data, 449 * type of 2 may point to file data in the btree and type == 3 may point to 450 * extents. 451 * 452 * offset is the starting byte offset for this key in the stream. 453 * 454 * btrfs_disk_key is in disk byte order. struct btrfs_key is always 455 * in cpu native order. Otherwise they are identical and their sizes 456 * should be the same (ie both packed) 457 */ 458 struct btrfs_disk_key { 459 __le64 objectid; 460 __u8 type; 461 __le64 offset; 462 } __attribute__ ((__packed__)); 463 464 struct btrfs_key { 465 __u64 objectid; 466 __u8 type; 467 __u64 offset; 468 } __attribute__ ((__packed__)); 469 470 /* 471 * Every tree block (leaf or node) starts with this header. 472 */ 473 struct btrfs_header { 474 /* These first four must match the super block */ 475 __u8 csum[BTRFS_CSUM_SIZE]; 476 /* FS specific uuid */ 477 __u8 fsid[BTRFS_FSID_SIZE]; 478 /* Which block this node is supposed to live in */ 479 __le64 bytenr; 480 __le64 flags; 481 482 /* Allowed to be different from the super from here on down */ 483 __u8 chunk_tree_uuid[BTRFS_UUID_SIZE]; 484 __le64 generation; 485 __le64 owner; 486 __le32 nritems; 487 __u8 level; 488 } __attribute__ ((__packed__)); 489 490 /* 491 * This is a very generous portion of the super block, giving us room to 492 * translate 14 chunks with 3 stripes each. 493 */ 494 #define BTRFS_SYSTEM_CHUNK_ARRAY_SIZE 2048 495 496 /* 497 * Just in case we somehow lose the roots and are not able to mount, we store 498 * an array of the roots from previous transactions in the super. 499 */ 500 #define BTRFS_NUM_BACKUP_ROOTS 4 501 struct btrfs_root_backup { 502 __le64 tree_root; 503 __le64 tree_root_gen; 504 505 __le64 chunk_root; 506 __le64 chunk_root_gen; 507 508 __le64 extent_root; 509 __le64 extent_root_gen; 510 511 __le64 fs_root; 512 __le64 fs_root_gen; 513 514 __le64 dev_root; 515 __le64 dev_root_gen; 516 517 __le64 csum_root; 518 __le64 csum_root_gen; 519 520 __le64 total_bytes; 521 __le64 bytes_used; 522 __le64 num_devices; 523 /* future */ 524 __le64 unused_64[4]; 525 526 __u8 tree_root_level; 527 __u8 chunk_root_level; 528 __u8 extent_root_level; 529 __u8 fs_root_level; 530 __u8 dev_root_level; 531 __u8 csum_root_level; 532 /* future and to align */ 533 __u8 unused_8[10]; 534 } __attribute__ ((__packed__)); 535 536 /* 537 * A leaf is full of items. offset and size tell us where to find the item in 538 * the leaf (relative to the start of the data area) 539 */ 540 struct btrfs_item { 541 struct btrfs_disk_key key; 542 __le32 offset; 543 __le32 size; 544 } __attribute__ ((__packed__)); 545 546 /* 547 * Leaves have an item area and a data area: 548 * [item0, item1....itemN] [free space] [dataN...data1, data0] 549 * 550 * The data is separate from the items to get the keys closer together during 551 * searches. 552 */ 553 struct btrfs_leaf { 554 struct btrfs_header header; 555 struct btrfs_item items[]; 556 } __attribute__ ((__packed__)); 557 558 /* 559 * All non-leaf blocks are nodes, they hold only keys and pointers to other 560 * blocks. 561 */ 562 struct btrfs_key_ptr { 563 struct btrfs_disk_key key; 564 __le64 blockptr; 565 __le64 generation; 566 } __attribute__ ((__packed__)); 567 568 struct btrfs_node { 569 struct btrfs_header header; 570 struct btrfs_key_ptr ptrs[]; 571 } __attribute__ ((__packed__)); 572 573 struct btrfs_dev_item { 574 /* the internal btrfs device id */ 575 __le64 devid; 576 577 /* size of the device */ 578 __le64 total_bytes; 579 580 /* bytes used */ 581 __le64 bytes_used; 582 583 /* optimal io alignment for this device */ 584 __le32 io_align; 585 586 /* optimal io width for this device */ 587 __le32 io_width; 588 589 /* minimal io size for this device */ 590 __le32 sector_size; 591 592 /* type and info about this device */ 593 __le64 type; 594 595 /* expected generation for this device */ 596 __le64 generation; 597 598 /* 599 * starting byte of this partition on the device, 600 * to allow for stripe alignment in the future 601 */ 602 __le64 start_offset; 603 604 /* grouping information for allocation decisions */ 605 __le32 dev_group; 606 607 /* seek speed 0-100 where 100 is fastest */ 608 __u8 seek_speed; 609 610 /* bandwidth 0-100 where 100 is fastest */ 611 __u8 bandwidth; 612 613 /* btrfs generated uuid for this device */ 614 __u8 uuid[BTRFS_UUID_SIZE]; 615 616 /* uuid of FS who owns this device */ 617 __u8 fsid[BTRFS_UUID_SIZE]; 618 } __attribute__ ((__packed__)); 619 620 struct btrfs_stripe { 621 __le64 devid; 622 __le64 offset; 623 __u8 dev_uuid[BTRFS_UUID_SIZE]; 624 } __attribute__ ((__packed__)); 625 626 struct btrfs_chunk { 627 /* size of this chunk in bytes */ 628 __le64 length; 629 630 /* objectid of the root referencing this chunk */ 631 __le64 owner; 632 633 __le64 stripe_len; 634 __le64 type; 635 636 /* optimal io alignment for this chunk */ 637 __le32 io_align; 638 639 /* optimal io width for this chunk */ 640 __le32 io_width; 641 642 /* minimal io size for this chunk */ 643 __le32 sector_size; 644 645 /* 2^16 stripes is quite a lot, a second limit is the size of a single 646 * item in the btree 647 */ 648 __le16 num_stripes; 649 650 /* sub stripes only matter for raid10 */ 651 __le16 sub_stripes; 652 struct btrfs_stripe stripe; 653 /* additional stripes go here */ 654 } __attribute__ ((__packed__)); 655 656 /* 657 * The super block basically lists the main trees of the FS. 658 */ 659 struct btrfs_super_block { 660 /* The first 4 fields must match struct btrfs_header */ 661 __u8 csum[BTRFS_CSUM_SIZE]; 662 /* FS specific UUID, visible to user */ 663 __u8 fsid[BTRFS_FSID_SIZE]; 664 /* This block number */ 665 __le64 bytenr; 666 __le64 flags; 667 668 /* Allowed to be different from the btrfs_header from here own down */ 669 __le64 magic; 670 __le64 generation; 671 __le64 root; 672 __le64 chunk_root; 673 __le64 log_root; 674 675 /* 676 * This member has never been utilized since the very beginning, thus 677 * it's always 0 regardless of kernel version. We always use 678 * generation + 1 to read log tree root. So here we mark it deprecated. 679 */ 680 __le64 __unused_log_root_transid; 681 __le64 total_bytes; 682 __le64 bytes_used; 683 __le64 root_dir_objectid; 684 __le64 num_devices; 685 __le32 sectorsize; 686 __le32 nodesize; 687 __le32 __unused_leafsize; 688 __le32 stripesize; 689 __le32 sys_chunk_array_size; 690 __le64 chunk_root_generation; 691 __le64 compat_flags; 692 __le64 compat_ro_flags; 693 __le64 incompat_flags; 694 __le16 csum_type; 695 __u8 root_level; 696 __u8 chunk_root_level; 697 __u8 log_root_level; 698 struct btrfs_dev_item dev_item; 699 700 char label[BTRFS_LABEL_SIZE]; 701 702 __le64 cache_generation; 703 __le64 uuid_tree_generation; 704 705 /* The UUID written into btree blocks */ 706 __u8 metadata_uuid[BTRFS_FSID_SIZE]; 707 708 __u64 nr_global_roots; 709 710 /* Future expansion */ 711 __le64 reserved[27]; 712 __u8 sys_chunk_array[BTRFS_SYSTEM_CHUNK_ARRAY_SIZE]; 713 struct btrfs_root_backup super_roots[BTRFS_NUM_BACKUP_ROOTS]; 714 715 /* Padded to 4096 bytes */ 716 __u8 padding[565]; 717 } __attribute__ ((__packed__)); 718 719 #define BTRFS_FREE_SPACE_EXTENT 1 720 #define BTRFS_FREE_SPACE_BITMAP 2 721 722 struct btrfs_free_space_entry { 723 __le64 offset; 724 __le64 bytes; 725 __u8 type; 726 } __attribute__ ((__packed__)); 727 728 struct btrfs_free_space_header { 729 struct btrfs_disk_key location; 730 __le64 generation; 731 __le64 num_entries; 732 __le64 num_bitmaps; 733 } __attribute__ ((__packed__)); 734 735 struct btrfs_raid_stride { 736 /* The id of device this raid extent lives on. */ 737 __le64 devid; 738 /* The physical location on disk. */ 739 __le64 physical; 740 } __attribute__ ((__packed__)); 741 742 /* The stripe_extent::encoding, 1:1 mapping of enum btrfs_raid_types. */ 743 #define BTRFS_STRIPE_RAID0 1 744 #define BTRFS_STRIPE_RAID1 2 745 #define BTRFS_STRIPE_DUP 3 746 #define BTRFS_STRIPE_RAID10 4 747 #define BTRFS_STRIPE_RAID5 5 748 #define BTRFS_STRIPE_RAID6 6 749 #define BTRFS_STRIPE_RAID1C3 7 750 #define BTRFS_STRIPE_RAID1C4 8 751 752 struct btrfs_stripe_extent { 753 __u8 encoding; 754 __u8 reserved[7]; 755 /* An array of raid strides this stripe is composed of. */ 756 struct btrfs_raid_stride strides[]; 757 } __attribute__ ((__packed__)); 758 759 #define BTRFS_HEADER_FLAG_WRITTEN (1ULL << 0) 760 #define BTRFS_HEADER_FLAG_RELOC (1ULL << 1) 761 762 /* Super block flags */ 763 /* Errors detected */ 764 #define BTRFS_SUPER_FLAG_ERROR (1ULL << 2) 765 766 #define BTRFS_SUPER_FLAG_SEEDING (1ULL << 32) 767 #define BTRFS_SUPER_FLAG_METADUMP (1ULL << 33) 768 #define BTRFS_SUPER_FLAG_METADUMP_V2 (1ULL << 34) 769 #define BTRFS_SUPER_FLAG_CHANGING_FSID (1ULL << 35) 770 #define BTRFS_SUPER_FLAG_CHANGING_FSID_V2 (1ULL << 36) 771 772 773 /* 774 * items in the extent btree are used to record the objectid of the 775 * owner of the block and the number of references 776 */ 777 778 struct btrfs_extent_item { 779 __le64 refs; 780 __le64 generation; 781 __le64 flags; 782 } __attribute__ ((__packed__)); 783 784 struct btrfs_extent_item_v0 { 785 __le32 refs; 786 } __attribute__ ((__packed__)); 787 788 789 #define BTRFS_EXTENT_FLAG_DATA (1ULL << 0) 790 #define BTRFS_EXTENT_FLAG_TREE_BLOCK (1ULL << 1) 791 792 /* following flags only apply to tree blocks */ 793 794 /* use full backrefs for extent pointers in the block */ 795 #define BTRFS_BLOCK_FLAG_FULL_BACKREF (1ULL << 8) 796 797 #define BTRFS_BACKREF_REV_MAX 256 798 #define BTRFS_BACKREF_REV_SHIFT 56 799 #define BTRFS_BACKREF_REV_MASK (((u64)BTRFS_BACKREF_REV_MAX - 1) << \ 800 BTRFS_BACKREF_REV_SHIFT) 801 802 #define BTRFS_OLD_BACKREF_REV 0 803 #define BTRFS_MIXED_BACKREF_REV 1 804 805 /* 806 * this flag is only used internally by scrub and may be changed at any time 807 * it is only declared here to avoid collisions 808 */ 809 #define BTRFS_EXTENT_FLAG_SUPER (1ULL << 48) 810 811 struct btrfs_tree_block_info { 812 struct btrfs_disk_key key; 813 __u8 level; 814 } __attribute__ ((__packed__)); 815 816 struct btrfs_extent_data_ref { 817 __le64 root; 818 __le64 objectid; 819 __le64 offset; 820 __le32 count; 821 } __attribute__ ((__packed__)); 822 823 struct btrfs_shared_data_ref { 824 __le32 count; 825 } __attribute__ ((__packed__)); 826 827 struct btrfs_extent_owner_ref { 828 __le64 root_id; 829 } __attribute__ ((__packed__)); 830 831 struct btrfs_extent_inline_ref { 832 __u8 type; 833 __le64 offset; 834 } __attribute__ ((__packed__)); 835 836 /* dev extents record free space on individual devices. The owner 837 * field points back to the chunk allocation mapping tree that allocated 838 * the extent. The chunk tree uuid field is a way to double check the owner 839 */ 840 struct btrfs_dev_extent { 841 __le64 chunk_tree; 842 __le64 chunk_objectid; 843 __le64 chunk_offset; 844 __le64 length; 845 __u8 chunk_tree_uuid[BTRFS_UUID_SIZE]; 846 } __attribute__ ((__packed__)); 847 848 struct btrfs_inode_ref { 849 __le64 index; 850 __le16 name_len; 851 /* name goes here */ 852 } __attribute__ ((__packed__)); 853 854 struct btrfs_inode_extref { 855 __le64 parent_objectid; 856 __le64 index; 857 __le16 name_len; 858 __u8 name[]; 859 /* name goes here */ 860 } __attribute__ ((__packed__)); 861 862 struct btrfs_timespec { 863 __le64 sec; 864 __le32 nsec; 865 } __attribute__ ((__packed__)); 866 867 struct btrfs_inode_item { 868 /* nfs style generation number */ 869 __le64 generation; 870 /* transid that last touched this inode */ 871 __le64 transid; 872 __le64 size; 873 __le64 nbytes; 874 __le64 block_group; 875 __le32 nlink; 876 __le32 uid; 877 __le32 gid; 878 __le32 mode; 879 __le64 rdev; 880 __le64 flags; 881 882 /* modification sequence number for NFS */ 883 __le64 sequence; 884 885 /* 886 * a little future expansion, for more than this we can 887 * just grow the inode item and version it 888 */ 889 __le64 reserved[4]; 890 struct btrfs_timespec atime; 891 struct btrfs_timespec ctime; 892 struct btrfs_timespec mtime; 893 struct btrfs_timespec otime; 894 } __attribute__ ((__packed__)); 895 896 struct btrfs_dir_log_item { 897 __le64 end; 898 } __attribute__ ((__packed__)); 899 900 struct btrfs_dir_item { 901 struct btrfs_disk_key location; 902 __le64 transid; 903 __le16 data_len; 904 __le16 name_len; 905 __u8 type; 906 } __attribute__ ((__packed__)); 907 908 #define BTRFS_ROOT_SUBVOL_RDONLY (1ULL << 0) 909 910 /* 911 * Internal in-memory flag that a subvolume has been marked for deletion but 912 * still visible as a directory 913 */ 914 #define BTRFS_ROOT_SUBVOL_DEAD (1ULL << 48) 915 916 struct btrfs_root_item { 917 struct btrfs_inode_item inode; 918 __le64 generation; 919 __le64 root_dirid; 920 __le64 bytenr; 921 __le64 byte_limit; 922 __le64 bytes_used; 923 __le64 last_snapshot; 924 __le64 flags; 925 __le32 refs; 926 struct btrfs_disk_key drop_progress; 927 __u8 drop_level; 928 __u8 level; 929 930 /* 931 * The following fields appear after subvol_uuids+subvol_times 932 * were introduced. 933 */ 934 935 /* 936 * This generation number is used to test if the new fields are valid 937 * and up to date while reading the root item. Every time the root item 938 * is written out, the "generation" field is copied into this field. If 939 * anyone ever mounted the fs with an older kernel, we will have 940 * mismatching generation values here and thus must invalidate the 941 * new fields. See btrfs_update_root and btrfs_find_last_root for 942 * details. 943 * the offset of generation_v2 is also used as the start for the memset 944 * when invalidating the fields. 945 */ 946 __le64 generation_v2; 947 __u8 uuid[BTRFS_UUID_SIZE]; 948 __u8 parent_uuid[BTRFS_UUID_SIZE]; 949 __u8 received_uuid[BTRFS_UUID_SIZE]; 950 __le64 ctransid; /* updated when an inode changes */ 951 __le64 otransid; /* trans when created */ 952 __le64 stransid; /* trans when sent. non-zero for received subvol */ 953 __le64 rtransid; /* trans when received. non-zero for received subvol */ 954 struct btrfs_timespec ctime; 955 struct btrfs_timespec otime; 956 struct btrfs_timespec stime; 957 struct btrfs_timespec rtime; 958 __le64 reserved[8]; /* for future */ 959 } __attribute__ ((__packed__)); 960 961 /* 962 * Btrfs root item used to be smaller than current size. The old format ends 963 * at where member generation_v2 is. 964 */ 965 static inline __u32 btrfs_legacy_root_item_size(void) 966 { 967 return offsetof(struct btrfs_root_item, generation_v2); 968 } 969 970 /* 971 * this is used for both forward and backward root refs 972 */ 973 struct btrfs_root_ref { 974 __le64 dirid; 975 __le64 sequence; 976 __le16 name_len; 977 } __attribute__ ((__packed__)); 978 979 struct btrfs_disk_balance_args { 980 /* 981 * profiles to operate on, single is denoted by 982 * BTRFS_AVAIL_ALLOC_BIT_SINGLE 983 */ 984 __le64 profiles; 985 986 /* 987 * usage filter 988 * BTRFS_BALANCE_ARGS_USAGE with a single value means '0..N' 989 * BTRFS_BALANCE_ARGS_USAGE_RANGE - range syntax, min..max 990 */ 991 union { 992 __le64 usage; 993 struct { 994 __le32 usage_min; 995 __le32 usage_max; 996 }; 997 }; 998 999 /* devid filter */ 1000 __le64 devid; 1001 1002 /* devid subset filter [pstart..pend) */ 1003 __le64 pstart; 1004 __le64 pend; 1005 1006 /* btrfs virtual address space subset filter [vstart..vend) */ 1007 __le64 vstart; 1008 __le64 vend; 1009 1010 /* 1011 * profile to convert to, single is denoted by 1012 * BTRFS_AVAIL_ALLOC_BIT_SINGLE 1013 */ 1014 __le64 target; 1015 1016 /* BTRFS_BALANCE_ARGS_* */ 1017 __le64 flags; 1018 1019 /* 1020 * BTRFS_BALANCE_ARGS_LIMIT with value 'limit' 1021 * BTRFS_BALANCE_ARGS_LIMIT_RANGE - the extend version can use minimum 1022 * and maximum 1023 */ 1024 union { 1025 __le64 limit; 1026 struct { 1027 __le32 limit_min; 1028 __le32 limit_max; 1029 }; 1030 }; 1031 1032 /* 1033 * Process chunks that cross stripes_min..stripes_max devices, 1034 * BTRFS_BALANCE_ARGS_STRIPES_RANGE 1035 */ 1036 __le32 stripes_min; 1037 __le32 stripes_max; 1038 1039 __le64 unused[6]; 1040 } __attribute__ ((__packed__)); 1041 1042 /* 1043 * store balance parameters to disk so that balance can be properly 1044 * resumed after crash or unmount 1045 */ 1046 struct btrfs_balance_item { 1047 /* BTRFS_BALANCE_* */ 1048 __le64 flags; 1049 1050 struct btrfs_disk_balance_args data; 1051 struct btrfs_disk_balance_args meta; 1052 struct btrfs_disk_balance_args sys; 1053 1054 __le64 unused[4]; 1055 } __attribute__ ((__packed__)); 1056 1057 enum { 1058 BTRFS_FILE_EXTENT_INLINE = 0, 1059 BTRFS_FILE_EXTENT_REG = 1, 1060 BTRFS_FILE_EXTENT_PREALLOC = 2, 1061 BTRFS_NR_FILE_EXTENT_TYPES = 3, 1062 }; 1063 1064 struct btrfs_file_extent_item { 1065 /* 1066 * transaction id that created this extent 1067 */ 1068 __le64 generation; 1069 /* 1070 * max number of bytes to hold this extent in ram 1071 * when we split a compressed extent we can't know how big 1072 * each of the resulting pieces will be. So, this is 1073 * an upper limit on the size of the extent in ram instead of 1074 * an exact limit. 1075 */ 1076 __le64 ram_bytes; 1077 1078 /* 1079 * 32 bits for the various ways we might encode the data, 1080 * including compression and encryption. If any of these 1081 * are set to something a given disk format doesn't understand 1082 * it is treated like an incompat flag for reading and writing, 1083 * but not for stat. 1084 */ 1085 __u8 compression; 1086 __u8 encryption; 1087 __le16 other_encoding; /* spare for later use */ 1088 1089 /* are we inline data or a real extent? */ 1090 __u8 type; 1091 1092 /* 1093 * disk space consumed by the extent, checksum blocks are included 1094 * in these numbers 1095 * 1096 * At this offset in the structure, the inline extent data start. 1097 */ 1098 __le64 disk_bytenr; 1099 __le64 disk_num_bytes; 1100 /* 1101 * the logical offset in file blocks (no csums) 1102 * this extent record is for. This allows a file extent to point 1103 * into the middle of an existing extent on disk, sharing it 1104 * between two snapshots (useful if some bytes in the middle of the 1105 * extent have changed 1106 */ 1107 __le64 offset; 1108 /* 1109 * the logical number of file blocks (no csums included). This 1110 * always reflects the size uncompressed and without encoding. 1111 */ 1112 __le64 num_bytes; 1113 1114 } __attribute__ ((__packed__)); 1115 1116 struct btrfs_csum_item { 1117 __u8 csum; 1118 } __attribute__ ((__packed__)); 1119 1120 struct btrfs_dev_stats_item { 1121 /* 1122 * grow this item struct at the end for future enhancements and keep 1123 * the existing values unchanged 1124 */ 1125 __le64 values[BTRFS_DEV_STAT_VALUES_MAX]; 1126 } __attribute__ ((__packed__)); 1127 1128 #define BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_ALWAYS 0 1129 #define BTRFS_DEV_REPLACE_ITEM_CONT_READING_FROM_SRCDEV_MODE_AVOID 1 1130 1131 struct btrfs_dev_replace_item { 1132 /* 1133 * grow this item struct at the end for future enhancements and keep 1134 * the existing values unchanged 1135 */ 1136 __le64 src_devid; 1137 __le64 cursor_left; 1138 __le64 cursor_right; 1139 __le64 cont_reading_from_srcdev_mode; 1140 1141 __le64 replace_state; 1142 __le64 time_started; 1143 __le64 time_stopped; 1144 __le64 num_write_errors; 1145 __le64 num_uncorrectable_read_errors; 1146 } __attribute__ ((__packed__)); 1147 1148 /* different types of block groups (and chunks) */ 1149 #define BTRFS_BLOCK_GROUP_DATA (1ULL << 0) 1150 #define BTRFS_BLOCK_GROUP_SYSTEM (1ULL << 1) 1151 #define BTRFS_BLOCK_GROUP_METADATA (1ULL << 2) 1152 #define BTRFS_BLOCK_GROUP_RAID0 (1ULL << 3) 1153 #define BTRFS_BLOCK_GROUP_RAID1 (1ULL << 4) 1154 #define BTRFS_BLOCK_GROUP_DUP (1ULL << 5) 1155 #define BTRFS_BLOCK_GROUP_RAID10 (1ULL << 6) 1156 #define BTRFS_BLOCK_GROUP_RAID5 (1ULL << 7) 1157 #define BTRFS_BLOCK_GROUP_RAID6 (1ULL << 8) 1158 #define BTRFS_BLOCK_GROUP_RAID1C3 (1ULL << 9) 1159 #define BTRFS_BLOCK_GROUP_RAID1C4 (1ULL << 10) 1160 #define BTRFS_BLOCK_GROUP_RESERVED (BTRFS_AVAIL_ALLOC_BIT_SINGLE | \ 1161 BTRFS_SPACE_INFO_GLOBAL_RSV) 1162 1163 #define BTRFS_BLOCK_GROUP_TYPE_MASK (BTRFS_BLOCK_GROUP_DATA | \ 1164 BTRFS_BLOCK_GROUP_SYSTEM | \ 1165 BTRFS_BLOCK_GROUP_METADATA) 1166 1167 #define BTRFS_BLOCK_GROUP_PROFILE_MASK (BTRFS_BLOCK_GROUP_RAID0 | \ 1168 BTRFS_BLOCK_GROUP_RAID1 | \ 1169 BTRFS_BLOCK_GROUP_RAID1C3 | \ 1170 BTRFS_BLOCK_GROUP_RAID1C4 | \ 1171 BTRFS_BLOCK_GROUP_RAID5 | \ 1172 BTRFS_BLOCK_GROUP_RAID6 | \ 1173 BTRFS_BLOCK_GROUP_DUP | \ 1174 BTRFS_BLOCK_GROUP_RAID10) 1175 #define BTRFS_BLOCK_GROUP_RAID56_MASK (BTRFS_BLOCK_GROUP_RAID5 | \ 1176 BTRFS_BLOCK_GROUP_RAID6) 1177 1178 #define BTRFS_BLOCK_GROUP_RAID1_MASK (BTRFS_BLOCK_GROUP_RAID1 | \ 1179 BTRFS_BLOCK_GROUP_RAID1C3 | \ 1180 BTRFS_BLOCK_GROUP_RAID1C4) 1181 1182 /* 1183 * We need a bit for restriper to be able to tell when chunks of type 1184 * SINGLE are available. This "extended" profile format is used in 1185 * fs_info->avail_*_alloc_bits (in-memory) and balance item fields 1186 * (on-disk). The corresponding on-disk bit in chunk.type is reserved 1187 * to avoid remappings between two formats in future. 1188 */ 1189 #define BTRFS_AVAIL_ALLOC_BIT_SINGLE (1ULL << 48) 1190 1191 /* 1192 * A fake block group type that is used to communicate global block reserve 1193 * size to userspace via the SPACE_INFO ioctl. 1194 */ 1195 #define BTRFS_SPACE_INFO_GLOBAL_RSV (1ULL << 49) 1196 1197 #define BTRFS_EXTENDED_PROFILE_MASK (BTRFS_BLOCK_GROUP_PROFILE_MASK | \ 1198 BTRFS_AVAIL_ALLOC_BIT_SINGLE) 1199 1200 static inline __u64 chunk_to_extended(__u64 flags) 1201 { 1202 if ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0) 1203 flags |= BTRFS_AVAIL_ALLOC_BIT_SINGLE; 1204 1205 return flags; 1206 } 1207 static inline __u64 extended_to_chunk(__u64 flags) 1208 { 1209 return flags & ~BTRFS_AVAIL_ALLOC_BIT_SINGLE; 1210 } 1211 1212 struct btrfs_block_group_item { 1213 __le64 used; 1214 __le64 chunk_objectid; 1215 __le64 flags; 1216 } __attribute__ ((__packed__)); 1217 1218 struct btrfs_free_space_info { 1219 __le32 extent_count; 1220 __le32 flags; 1221 } __attribute__ ((__packed__)); 1222 1223 #define BTRFS_FREE_SPACE_USING_BITMAPS (1ULL << 0) 1224 1225 #define BTRFS_QGROUP_LEVEL_SHIFT 48 1226 static inline __u16 btrfs_qgroup_level(__u64 qgroupid) 1227 { 1228 return (__u16)(qgroupid >> BTRFS_QGROUP_LEVEL_SHIFT); 1229 } 1230 1231 /* 1232 * is subvolume quota turned on? 1233 */ 1234 #define BTRFS_QGROUP_STATUS_FLAG_ON (1ULL << 0) 1235 /* 1236 * RESCAN is set during the initialization phase 1237 */ 1238 #define BTRFS_QGROUP_STATUS_FLAG_RESCAN (1ULL << 1) 1239 /* 1240 * Some qgroup entries are known to be out of date, 1241 * either because the configuration has changed in a way that 1242 * makes a rescan necessary, or because the fs has been mounted 1243 * with a non-qgroup-aware version. 1244 * Turning qouta off and on again makes it inconsistent, too. 1245 */ 1246 #define BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT (1ULL << 2) 1247 1248 /* 1249 * Whether or not this filesystem is using simple quotas. Not exactly the 1250 * incompat bit, because we support using simple quotas, disabling it, then 1251 * going back to full qgroup quotas. 1252 */ 1253 #define BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE (1ULL << 3) 1254 1255 #define BTRFS_QGROUP_STATUS_FLAGS_MASK (BTRFS_QGROUP_STATUS_FLAG_ON | \ 1256 BTRFS_QGROUP_STATUS_FLAG_RESCAN | \ 1257 BTRFS_QGROUP_STATUS_FLAG_INCONSISTENT | \ 1258 BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE) 1259 1260 #define BTRFS_QGROUP_STATUS_VERSION 1 1261 1262 struct btrfs_qgroup_status_item { 1263 __le64 version; 1264 /* 1265 * the generation is updated during every commit. As older 1266 * versions of btrfs are not aware of qgroups, it will be 1267 * possible to detect inconsistencies by checking the 1268 * generation on mount time 1269 */ 1270 __le64 generation; 1271 1272 /* flag definitions see above */ 1273 __le64 flags; 1274 1275 /* 1276 * only used during scanning to record the progress 1277 * of the scan. It contains a logical address 1278 */ 1279 __le64 rescan; 1280 1281 /* 1282 * The generation when quotas were last enabled. Used by simple quotas to 1283 * avoid decrementing when freeing an extent that was written before 1284 * enable. 1285 * 1286 * Set only if flags contain BTRFS_QGROUP_STATUS_FLAG_SIMPLE_MODE. 1287 */ 1288 __le64 enable_gen; 1289 } __attribute__ ((__packed__)); 1290 1291 struct btrfs_qgroup_info_item { 1292 __le64 generation; 1293 __le64 rfer; 1294 __le64 rfer_cmpr; 1295 __le64 excl; 1296 __le64 excl_cmpr; 1297 } __attribute__ ((__packed__)); 1298 1299 struct btrfs_qgroup_limit_item { 1300 /* 1301 * only updated when any of the other values change 1302 */ 1303 __le64 flags; 1304 __le64 max_rfer; 1305 __le64 max_excl; 1306 __le64 rsv_rfer; 1307 __le64 rsv_excl; 1308 } __attribute__ ((__packed__)); 1309 1310 struct btrfs_verity_descriptor_item { 1311 /* Size of the verity descriptor in bytes */ 1312 __le64 size; 1313 /* 1314 * When we implement support for fscrypt, we will need to encrypt the 1315 * Merkle tree for encrypted verity files. These 128 bits are for the 1316 * eventual storage of an fscrypt initialization vector. 1317 */ 1318 __le64 reserved[2]; 1319 __u8 encryption; 1320 } __attribute__ ((__packed__)); 1321 1322 #endif /* _BTRFS_CTREE_H_ */ 1323