1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc. 4 * Copyright (c) 2013 Red Hat, Inc. 5 * All Rights Reserved. 6 */ 7 #ifndef __XFS_DA_FORMAT_H__ 8 #define __XFS_DA_FORMAT_H__ 9 10 /* 11 * This structure is common to both leaf nodes and non-leaf nodes in the Btree. 12 * 13 * It is used to manage a doubly linked list of all blocks at the same 14 * level in the Btree, and to identify which type of block this is. 15 */ 16 #define XFS_DA_NODE_MAGIC 0xfebe /* magic number: non-leaf blocks */ 17 #define XFS_ATTR_LEAF_MAGIC 0xfbee /* magic number: attribute leaf blks */ 18 #define XFS_DIR2_LEAF1_MAGIC 0xd2f1 /* magic number: v2 dirlf single blks */ 19 #define XFS_DIR2_LEAFN_MAGIC 0xd2ff /* magic number: v2 dirlf multi blks */ 20 21 typedef struct xfs_da_blkinfo { 22 __be32 forw; /* previous block in list */ 23 __be32 back; /* following block in list */ 24 __be16 magic; /* validity check on block */ 25 __be16 pad; /* unused */ 26 } xfs_da_blkinfo_t; 27 28 /* 29 * CRC enabled directory structure types 30 * 31 * The headers change size for the additional verification information, but 32 * otherwise the tree layouts and contents are unchanged. Hence the da btree 33 * code can use the struct xfs_da_blkinfo for manipulating the tree links and 34 * magic numbers without modification for both v2 and v3 nodes. 35 */ 36 #define XFS_DA3_NODE_MAGIC 0x3ebe /* magic number: non-leaf blocks */ 37 #define XFS_ATTR3_LEAF_MAGIC 0x3bee /* magic number: attribute leaf blks */ 38 #define XFS_DIR3_LEAF1_MAGIC 0x3df1 /* magic number: v3 dirlf single blks */ 39 #define XFS_DIR3_LEAFN_MAGIC 0x3dff /* magic number: v3 dirlf multi blks */ 40 41 struct xfs_da3_blkinfo { 42 /* 43 * the node link manipulation code relies on the fact that the first 44 * element of this structure is the struct xfs_da_blkinfo so it can 45 * ignore the differences in the rest of the structures. 46 */ 47 struct xfs_da_blkinfo hdr; 48 __be32 crc; /* CRC of block */ 49 __be64 blkno; /* first block of the buffer */ 50 __be64 lsn; /* sequence number of last write */ 51 uuid_t uuid; /* filesystem we belong to */ 52 __be64 owner; /* inode that owns the block */ 53 }; 54 55 /* 56 * This is the structure of the root and intermediate nodes in the Btree. 57 * The leaf nodes are defined above. 58 * 59 * Entries are not packed. 60 * 61 * Since we have duplicate keys, use a binary search but always follow 62 * all match in the block, not just the first match found. 63 */ 64 #define XFS_DA_NODE_MAXDEPTH 5 /* max depth of Btree */ 65 66 typedef struct xfs_da_node_hdr { 67 struct xfs_da_blkinfo info; /* block type, links, etc. */ 68 __be16 __count; /* count of active entries */ 69 __be16 __level; /* level above leaves (leaf == 0) */ 70 } xfs_da_node_hdr_t; 71 72 struct xfs_da3_node_hdr { 73 struct xfs_da3_blkinfo info; /* block type, links, etc. */ 74 __be16 __count; /* count of active entries */ 75 __be16 __level; /* level above leaves (leaf == 0) */ 76 __be32 __pad32; 77 }; 78 79 #define XFS_DA3_NODE_CRC_OFF (offsetof(struct xfs_da3_node_hdr, info.crc)) 80 81 typedef struct xfs_da_node_entry { 82 __be32 hashval; /* hash value for this descendant */ 83 __be32 before; /* Btree block before this key */ 84 } xfs_da_node_entry_t; 85 86 typedef struct xfs_da_intnode { 87 struct xfs_da_node_hdr hdr; 88 struct xfs_da_node_entry __btree[]; 89 } xfs_da_intnode_t; 90 91 struct xfs_da3_intnode { 92 struct xfs_da3_node_hdr hdr; 93 struct xfs_da_node_entry __btree[]; 94 }; 95 96 /* 97 * Directory version 2. 98 * 99 * There are 4 possible formats: 100 * - shortform - embedded into the inode 101 * - single block - data with embedded leaf at the end 102 * - multiple data blocks, single leaf+freeindex block 103 * - data blocks, node and leaf blocks (btree), freeindex blocks 104 * 105 * Note: many node blocks structures and constants are shared with the attr 106 * code and defined in xfs_da_btree.h. 107 */ 108 109 #define XFS_DIR2_BLOCK_MAGIC 0x58443242 /* XD2B: single block dirs */ 110 #define XFS_DIR2_DATA_MAGIC 0x58443244 /* XD2D: multiblock dirs */ 111 #define XFS_DIR2_FREE_MAGIC 0x58443246 /* XD2F: free index blocks */ 112 113 /* 114 * Directory Version 3 With CRCs. 115 * 116 * The tree formats are the same as for version 2 directories. The difference 117 * is in the block header and dirent formats. In many cases the v3 structures 118 * use v2 definitions as they are no different and this makes code sharing much 119 * easier. 120 * 121 * Also, the xfs_dir3_*() functions handle both v2 and v3 formats - if the 122 * format is v2 then they switch to the existing v2 code, or the format is v3 123 * they implement the v3 functionality. This means the existing dir2 is a mix of 124 * xfs_dir2/xfs_dir3 calls and functions. The xfs_dir3 functions are called 125 * where there is a difference in the formats, otherwise the code is unchanged. 126 * 127 * Where it is possible, the code decides what to do based on the magic numbers 128 * in the blocks rather than feature bits in the superblock. This means the code 129 * is as independent of the external XFS code as possible as doesn't require 130 * passing struct xfs_mount pointers into places where it isn't really 131 * necessary. 132 * 133 * Version 3 includes: 134 * 135 * - a larger block header for CRC and identification purposes and so the 136 * offsets of all the structures inside the blocks are different. 137 * 138 * - new magic numbers to be able to detect the v2/v3 types on the fly. 139 */ 140 141 #define XFS_DIR3_BLOCK_MAGIC 0x58444233 /* XDB3: single block dirs */ 142 #define XFS_DIR3_DATA_MAGIC 0x58444433 /* XDD3: multiblock dirs */ 143 #define XFS_DIR3_FREE_MAGIC 0x58444633 /* XDF3: free index blocks */ 144 145 /* 146 * Dirents in version 3 directories have a file type field. Additions to this 147 * list are an on-disk format change, requiring feature bits. Valid values 148 * are as follows: 149 */ 150 #define XFS_DIR3_FT_UNKNOWN 0 151 #define XFS_DIR3_FT_REG_FILE 1 152 #define XFS_DIR3_FT_DIR 2 153 #define XFS_DIR3_FT_CHRDEV 3 154 #define XFS_DIR3_FT_BLKDEV 4 155 #define XFS_DIR3_FT_FIFO 5 156 #define XFS_DIR3_FT_SOCK 6 157 #define XFS_DIR3_FT_SYMLINK 7 158 #define XFS_DIR3_FT_WHT 8 159 160 #define XFS_DIR3_FT_MAX 9 161 162 /* 163 * Byte offset in data block and shortform entry. 164 */ 165 typedef uint16_t xfs_dir2_data_off_t; 166 #define NULLDATAOFF 0xffffU 167 typedef uint xfs_dir2_data_aoff_t; /* argument form */ 168 169 /* 170 * Offset in data space of a data entry. 171 */ 172 typedef uint32_t xfs_dir2_dataptr_t; 173 #define XFS_DIR2_MAX_DATAPTR ((xfs_dir2_dataptr_t)0xffffffff) 174 #define XFS_DIR2_NULL_DATAPTR ((xfs_dir2_dataptr_t)0) 175 176 /* 177 * Byte offset in a directory. 178 */ 179 typedef xfs_off_t xfs_dir2_off_t; 180 181 /* 182 * Directory block number (logical dirblk in file) 183 */ 184 typedef uint32_t xfs_dir2_db_t; 185 186 #define XFS_INO32_SIZE 4 187 #define XFS_INO64_SIZE 8 188 #define XFS_INO64_DIFF (XFS_INO64_SIZE - XFS_INO32_SIZE) 189 190 #define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL) 191 192 /* 193 * Directory layout when stored internal to an inode. 194 * 195 * Small directories are packed as tightly as possible so as to fit into the 196 * literal area of the inode. These "shortform" directories consist of a 197 * single xfs_dir2_sf_hdr header followed by zero or more xfs_dir2_sf_entry 198 * structures. Due the different inode number storage size and the variable 199 * length name field in the xfs_dir2_sf_entry all these structure are 200 * variable length, and the accessors in this file should be used to iterate 201 * over them. 202 */ 203 typedef struct xfs_dir2_sf_hdr { 204 uint8_t count; /* count of entries */ 205 uint8_t i8count; /* count of 8-byte inode #s */ 206 uint8_t parent[8]; /* parent dir inode number */ 207 } __packed xfs_dir2_sf_hdr_t; 208 209 typedef struct xfs_dir2_sf_entry { 210 __u8 namelen; /* actual name length */ 211 __u8 offset[2]; /* saved offset */ 212 __u8 name[]; /* name, variable size */ 213 /* 214 * A single byte containing the file type field follows the inode 215 * number for version 3 directory entries. 216 * 217 * A 64-bit or 32-bit inode number follows here, at a variable offset 218 * after the name. 219 */ 220 } __packed xfs_dir2_sf_entry_t; 221 222 static inline int xfs_dir2_sf_hdr_size(int i8count) 223 { 224 return sizeof(struct xfs_dir2_sf_hdr) - 225 (i8count == 0) * XFS_INO64_DIFF; 226 } 227 228 static inline xfs_dir2_data_aoff_t 229 xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep) 230 { 231 return get_unaligned_be16(sfep->offset); 232 } 233 234 static inline void 235 xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off) 236 { 237 put_unaligned_be16(off, sfep->offset); 238 } 239 240 static inline struct xfs_dir2_sf_entry * 241 xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr) 242 { 243 return (struct xfs_dir2_sf_entry *) 244 ((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count)); 245 } 246 247 /* 248 * Data block structures. 249 * 250 * A pure data block looks like the following drawing on disk: 251 * 252 * +-------------------------------------------------+ 253 * | xfs_dir2_data_hdr_t | 254 * +-------------------------------------------------+ 255 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | 256 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | 257 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | 258 * | ... | 259 * +-------------------------------------------------+ 260 * | unused space | 261 * +-------------------------------------------------+ 262 * 263 * As all the entries are variable size structures the accessors below should 264 * be used to iterate over them. 265 * 266 * In addition to the pure data blocks for the data and node formats, 267 * most structures are also used for the combined data/freespace "block" 268 * format below. 269 */ 270 271 #define XFS_DIR2_DATA_ALIGN_LOG 3 /* i.e., 8 bytes */ 272 #define XFS_DIR2_DATA_ALIGN (1 << XFS_DIR2_DATA_ALIGN_LOG) 273 #define XFS_DIR2_DATA_FREE_TAG 0xffff 274 #define XFS_DIR2_DATA_FD_COUNT 3 275 276 /* 277 * Directory address space divided into sections, 278 * spaces separated by 32GB. 279 */ 280 #define XFS_DIR2_MAX_SPACES 3 281 #define XFS_DIR2_SPACE_SIZE (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG)) 282 #define XFS_DIR2_DATA_SPACE 0 283 #define XFS_DIR2_DATA_OFFSET (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE) 284 285 /* 286 * Describe a free area in the data block. 287 * 288 * The freespace will be formatted as a xfs_dir2_data_unused_t. 289 */ 290 typedef struct xfs_dir2_data_free { 291 __be16 offset; /* start of freespace */ 292 __be16 length; /* length of freespace */ 293 } xfs_dir2_data_free_t; 294 295 /* 296 * Header for the data blocks. 297 * 298 * The code knows that XFS_DIR2_DATA_FD_COUNT is 3. 299 */ 300 typedef struct xfs_dir2_data_hdr { 301 __be32 magic; /* XFS_DIR2_DATA_MAGIC or */ 302 /* XFS_DIR2_BLOCK_MAGIC */ 303 xfs_dir2_data_free_t bestfree[XFS_DIR2_DATA_FD_COUNT]; 304 } xfs_dir2_data_hdr_t; 305 306 /* 307 * define a structure for all the verification fields we are adding to the 308 * directory block structures. This will be used in several structures. 309 * The magic number must be the first entry to align with all the dir2 310 * structures so we determine how to decode them just by the magic number. 311 */ 312 struct xfs_dir3_blk_hdr { 313 __be32 magic; /* magic number */ 314 __be32 crc; /* CRC of block */ 315 __be64 blkno; /* first block of the buffer */ 316 __be64 lsn; /* sequence number of last write */ 317 uuid_t uuid; /* filesystem we belong to */ 318 __be64 owner; /* inode that owns the block */ 319 }; 320 321 struct xfs_dir3_data_hdr { 322 struct xfs_dir3_blk_hdr hdr; 323 xfs_dir2_data_free_t best_free[XFS_DIR2_DATA_FD_COUNT]; 324 __be32 pad; /* 64 bit alignment */ 325 }; 326 327 #define XFS_DIR3_DATA_CRC_OFF offsetof(struct xfs_dir3_data_hdr, hdr.crc) 328 329 /* 330 * Active entry in a data block. 331 * 332 * Aligned to 8 bytes. After the variable length name field there is a 333 * 2 byte tag field, which can be accessed using xfs_dir3_data_entry_tag_p. 334 * 335 * For dir3 structures, there is file type field between the name and the tag. 336 * This can only be manipulated by helper functions. It is packed hard against 337 * the end of the name so any padding for rounding is between the file type and 338 * the tag. 339 */ 340 typedef struct xfs_dir2_data_entry { 341 __be64 inumber; /* inode number */ 342 __u8 namelen; /* name length */ 343 __u8 name[]; /* name bytes, no null */ 344 /* __u8 filetype; */ /* type of inode we point to */ 345 /* __be16 tag; */ /* starting offset of us */ 346 } xfs_dir2_data_entry_t; 347 348 /* 349 * Unused entry in a data block. 350 * 351 * Aligned to 8 bytes. Tag appears as the last 2 bytes and must be accessed 352 * using xfs_dir2_data_unused_tag_p. 353 */ 354 typedef struct xfs_dir2_data_unused { 355 __be16 freetag; /* XFS_DIR2_DATA_FREE_TAG */ 356 __be16 length; /* total free length */ 357 /* variable offset */ 358 __be16 tag; /* starting offset of us */ 359 } xfs_dir2_data_unused_t; 360 361 /* 362 * Pointer to a freespace's tag word. 363 */ 364 static inline __be16 * 365 xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup) 366 { 367 return (__be16 *)((char *)dup + 368 be16_to_cpu(dup->length) - sizeof(__be16)); 369 } 370 371 /* 372 * Leaf block structures. 373 * 374 * A pure leaf block looks like the following drawing on disk: 375 * 376 * +---------------------------+ 377 * | xfs_dir2_leaf_hdr_t | 378 * +---------------------------+ 379 * | xfs_dir2_leaf_entry_t | 380 * | xfs_dir2_leaf_entry_t | 381 * | xfs_dir2_leaf_entry_t | 382 * | xfs_dir2_leaf_entry_t | 383 * | ... | 384 * +---------------------------+ 385 * | xfs_dir2_data_off_t | 386 * | xfs_dir2_data_off_t | 387 * | xfs_dir2_data_off_t | 388 * | ... | 389 * +---------------------------+ 390 * | xfs_dir2_leaf_tail_t | 391 * +---------------------------+ 392 * 393 * The xfs_dir2_data_off_t members (bests) and tail are at the end of the block 394 * for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present 395 * for directories with separate leaf nodes and free space blocks 396 * (magic = XFS_DIR2_LEAFN_MAGIC). 397 * 398 * As all the entries are variable size structures the accessors below should 399 * be used to iterate over them. 400 */ 401 402 /* 403 * Offset of the leaf/node space. First block in this space 404 * is the btree root. 405 */ 406 #define XFS_DIR2_LEAF_SPACE 1 407 #define XFS_DIR2_LEAF_OFFSET (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE) 408 409 /* 410 * Leaf block header. 411 */ 412 typedef struct xfs_dir2_leaf_hdr { 413 xfs_da_blkinfo_t info; /* header for da routines */ 414 __be16 count; /* count of entries */ 415 __be16 stale; /* count of stale entries */ 416 } xfs_dir2_leaf_hdr_t; 417 418 struct xfs_dir3_leaf_hdr { 419 struct xfs_da3_blkinfo info; /* header for da routines */ 420 __be16 count; /* count of entries */ 421 __be16 stale; /* count of stale entries */ 422 __be32 pad; /* 64 bit alignment */ 423 }; 424 425 /* 426 * Leaf block entry. 427 */ 428 typedef struct xfs_dir2_leaf_entry { 429 __be32 hashval; /* hash value of name */ 430 __be32 address; /* address of data entry */ 431 } xfs_dir2_leaf_entry_t; 432 433 /* 434 * Leaf block tail. 435 */ 436 typedef struct xfs_dir2_leaf_tail { 437 __be32 bestcount; 438 } xfs_dir2_leaf_tail_t; 439 440 /* 441 * Leaf block. 442 */ 443 typedef struct xfs_dir2_leaf { 444 xfs_dir2_leaf_hdr_t hdr; /* leaf header */ 445 xfs_dir2_leaf_entry_t __ents[]; /* entries */ 446 } xfs_dir2_leaf_t; 447 448 struct xfs_dir3_leaf { 449 struct xfs_dir3_leaf_hdr hdr; /* leaf header */ 450 struct xfs_dir2_leaf_entry __ents[]; /* entries */ 451 }; 452 453 #define XFS_DIR3_LEAF_CRC_OFF offsetof(struct xfs_dir3_leaf_hdr, info.crc) 454 455 /* 456 * Get address of the bests array in the single-leaf block. 457 */ 458 static inline __be16 * 459 xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp) 460 { 461 return (__be16 *)ltp - be32_to_cpu(ltp->bestcount); 462 } 463 464 /* 465 * Free space block definitions for the node format. 466 */ 467 468 /* 469 * Offset of the freespace index. 470 */ 471 #define XFS_DIR2_FREE_SPACE 2 472 #define XFS_DIR2_FREE_OFFSET (XFS_DIR2_FREE_SPACE * XFS_DIR2_SPACE_SIZE) 473 474 typedef struct xfs_dir2_free_hdr { 475 __be32 magic; /* XFS_DIR2_FREE_MAGIC */ 476 __be32 firstdb; /* db of first entry */ 477 __be32 nvalid; /* count of valid entries */ 478 __be32 nused; /* count of used entries */ 479 } xfs_dir2_free_hdr_t; 480 481 typedef struct xfs_dir2_free { 482 xfs_dir2_free_hdr_t hdr; /* block header */ 483 __be16 bests[]; /* best free counts */ 484 /* unused entries are -1 */ 485 } xfs_dir2_free_t; 486 487 struct xfs_dir3_free_hdr { 488 struct xfs_dir3_blk_hdr hdr; 489 __be32 firstdb; /* db of first entry */ 490 __be32 nvalid; /* count of valid entries */ 491 __be32 nused; /* count of used entries */ 492 __be32 pad; /* 64 bit alignment */ 493 }; 494 495 struct xfs_dir3_free { 496 struct xfs_dir3_free_hdr hdr; 497 __be16 bests[]; /* best free counts */ 498 /* unused entries are -1 */ 499 }; 500 501 #define XFS_DIR3_FREE_CRC_OFF offsetof(struct xfs_dir3_free, hdr.hdr.crc) 502 503 /* 504 * Single block format. 505 * 506 * The single block format looks like the following drawing on disk: 507 * 508 * +-------------------------------------------------+ 509 * | xfs_dir2_data_hdr_t | 510 * +-------------------------------------------------+ 511 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | 512 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | 513 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t : 514 * | ... | 515 * +-------------------------------------------------+ 516 * | unused space | 517 * +-------------------------------------------------+ 518 * | ... | 519 * | xfs_dir2_leaf_entry_t | 520 * | xfs_dir2_leaf_entry_t | 521 * +-------------------------------------------------+ 522 * | xfs_dir2_block_tail_t | 523 * +-------------------------------------------------+ 524 * 525 * As all the entries are variable size structures the accessors below should 526 * be used to iterate over them. 527 */ 528 529 typedef struct xfs_dir2_block_tail { 530 __be32 count; /* count of leaf entries */ 531 __be32 stale; /* count of stale lf entries */ 532 } xfs_dir2_block_tail_t; 533 534 /* 535 * Pointer to the leaf entries embedded in a data block (1-block format) 536 */ 537 static inline struct xfs_dir2_leaf_entry * 538 xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp) 539 { 540 return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count); 541 } 542 543 544 /* 545 * Attribute storage layout 546 * 547 * Attribute lists are structured around Btrees where all the data 548 * elements are in the leaf nodes. Attribute names are hashed into an int, 549 * then that int is used as the index into the Btree. Since the hashval 550 * of an attribute name may not be unique, we may have duplicate keys. The 551 * internal links in the Btree are logical block offsets into the file. 552 * 553 * Struct leaf_entry's are packed from the top. Name/values grow from the 554 * bottom but are not packed. The freemap contains run-length-encoded entries 555 * for the free bytes after the leaf_entry's, but only the N largest such, 556 * smaller runs are dropped. When the freemap doesn't show enough space 557 * for an allocation, we compact the name/value area and try again. If we 558 * still don't have enough space, then we have to split the block. The 559 * name/value structs (both local and remote versions) must be 32bit aligned. 560 * 561 * Since we have duplicate hash keys, for each key that matches, compare 562 * the actual name string. The root and intermediate node search always 563 * takes the first-in-the-block key match found, so we should only have 564 * to work "forw"ard. If none matches, continue with the "forw"ard leaf 565 * nodes until the hash key changes or the attribute name is found. 566 * 567 * We store the fact that an attribute is a ROOT/USER/SECURE attribute in 568 * the leaf_entry. The namespaces are independent only because we also look 569 * at the namespace bit when we are looking for a matching attribute name. 570 * 571 * We also store an "incomplete" bit in the leaf_entry. It shows that an 572 * attribute is in the middle of being created and should not be shown to 573 * the user if we crash during the time that the bit is set. We clear the 574 * bit when we have finished setting up the attribute. We do this because 575 * we cannot create some large attributes inside a single transaction, and we 576 * need some indication that we weren't finished if we crash in the middle. 577 */ 578 #define XFS_ATTR_LEAF_MAPSIZE 3 /* how many freespace slots */ 579 580 /* 581 * Entries are packed toward the top as tight as possible. 582 */ 583 struct xfs_attr_shortform { 584 struct xfs_attr_sf_hdr { /* constant-structure header block */ 585 __be16 totsize; /* total bytes in shortform list */ 586 __u8 count; /* count of active entries */ 587 __u8 padding; 588 } hdr; 589 struct xfs_attr_sf_entry { 590 uint8_t namelen; /* actual length of name (no NULL) */ 591 uint8_t valuelen; /* actual length of value (no NULL) */ 592 uint8_t flags; /* flags bits (see xfs_attr_leaf.h) */ 593 uint8_t nameval[]; /* name & value bytes concatenated */ 594 } list[]; /* variable sized array */ 595 }; 596 597 typedef struct xfs_attr_leaf_map { /* RLE map of free bytes */ 598 __be16 base; /* base of free region */ 599 __be16 size; /* length of free region */ 600 } xfs_attr_leaf_map_t; 601 602 typedef struct xfs_attr_leaf_hdr { /* constant-structure header block */ 603 xfs_da_blkinfo_t info; /* block type, links, etc. */ 604 __be16 count; /* count of active leaf_entry's */ 605 __be16 usedbytes; /* num bytes of names/values stored */ 606 __be16 firstused; /* first used byte in name area */ 607 __u8 holes; /* != 0 if blk needs compaction */ 608 __u8 pad1; 609 xfs_attr_leaf_map_t freemap[XFS_ATTR_LEAF_MAPSIZE]; 610 /* N largest free regions */ 611 } xfs_attr_leaf_hdr_t; 612 613 typedef struct xfs_attr_leaf_entry { /* sorted on key, not name */ 614 __be32 hashval; /* hash value of name */ 615 __be16 nameidx; /* index into buffer of name/value */ 616 __u8 flags; /* LOCAL/ROOT/SECURE/INCOMPLETE flag */ 617 __u8 pad2; /* unused pad byte */ 618 } xfs_attr_leaf_entry_t; 619 620 typedef struct xfs_attr_leaf_name_local { 621 __be16 valuelen; /* number of bytes in value */ 622 __u8 namelen; /* length of name bytes */ 623 /* 624 * In Linux 6.5 this flex array was converted from nameval[1] to 625 * nameval[]. Be very careful here about extra padding at the end; 626 * see xfs_attr_leaf_entsize_local() for details. 627 */ 628 __u8 nameval[]; /* name/value bytes */ 629 } xfs_attr_leaf_name_local_t; 630 631 typedef struct xfs_attr_leaf_name_remote { 632 __be32 valueblk; /* block number of value bytes */ 633 __be32 valuelen; /* number of bytes in value */ 634 __u8 namelen; /* length of name bytes */ 635 /* 636 * In Linux 6.5 this flex array was converted from name[1] to name[]. 637 * Be very careful here about extra padding at the end; see 638 * xfs_attr_leaf_entsize_remote() for details. 639 */ 640 __u8 name[]; /* name bytes */ 641 } xfs_attr_leaf_name_remote_t; 642 643 typedef struct xfs_attr_leafblock { 644 xfs_attr_leaf_hdr_t hdr; /* constant-structure header block */ 645 xfs_attr_leaf_entry_t entries[]; /* sorted on key, not name */ 646 /* 647 * The rest of the block contains the following structures after the 648 * leaf entries, growing from the bottom up. The variables are never 649 * referenced and definining them can actually make gcc optimize away 650 * accesses to the 'entries' array above index 0 so don't do that. 651 * 652 * xfs_attr_leaf_name_local_t namelist; 653 * xfs_attr_leaf_name_remote_t valuelist; 654 */ 655 } xfs_attr_leafblock_t; 656 657 /* 658 * CRC enabled leaf structures. Called "version 3" structures to match the 659 * version number of the directory and dablk structures for this feature, and 660 * attr2 is already taken by the variable inode attribute fork size feature. 661 */ 662 struct xfs_attr3_leaf_hdr { 663 struct xfs_da3_blkinfo info; 664 __be16 count; 665 __be16 usedbytes; 666 __be16 firstused; 667 __u8 holes; 668 __u8 pad1; 669 struct xfs_attr_leaf_map freemap[XFS_ATTR_LEAF_MAPSIZE]; 670 __be32 pad2; /* 64 bit alignment */ 671 }; 672 673 #define XFS_ATTR3_LEAF_CRC_OFF (offsetof(struct xfs_attr3_leaf_hdr, info.crc)) 674 675 struct xfs_attr3_leafblock { 676 struct xfs_attr3_leaf_hdr hdr; 677 struct xfs_attr_leaf_entry entries[]; 678 679 /* 680 * The rest of the block contains the following structures after the 681 * leaf entries, growing from the bottom up. The variables are never 682 * referenced, the locations accessed purely from helper functions. 683 * 684 * struct xfs_attr_leaf_name_local 685 * struct xfs_attr_leaf_name_remote 686 */ 687 }; 688 689 /* 690 * Special value to represent fs block size in the leaf header firstused field. 691 * Only used when block size overflows the 2-bytes available on disk. 692 */ 693 #define XFS_ATTR3_LEAF_NULLOFF 0 694 695 /* 696 * Flags used in the leaf_entry[i].flags field. 697 */ 698 #define XFS_ATTR_LOCAL_BIT 0 /* attr is stored locally */ 699 #define XFS_ATTR_ROOT_BIT 1 /* limit access to trusted attrs */ 700 #define XFS_ATTR_SECURE_BIT 2 /* limit access to secure attrs */ 701 #define XFS_ATTR_INCOMPLETE_BIT 7 /* attr in middle of create/delete */ 702 #define XFS_ATTR_LOCAL (1u << XFS_ATTR_LOCAL_BIT) 703 #define XFS_ATTR_ROOT (1u << XFS_ATTR_ROOT_BIT) 704 #define XFS_ATTR_SECURE (1u << XFS_ATTR_SECURE_BIT) 705 #define XFS_ATTR_INCOMPLETE (1u << XFS_ATTR_INCOMPLETE_BIT) 706 #define XFS_ATTR_NSP_ONDISK_MASK (XFS_ATTR_ROOT | XFS_ATTR_SECURE) 707 708 /* 709 * Alignment for namelist and valuelist entries (since they are mixed 710 * there can be only one alignment value) 711 */ 712 #define XFS_ATTR_LEAF_NAME_ALIGN ((uint)sizeof(xfs_dablk_t)) 713 714 static inline int 715 xfs_attr3_leaf_hdr_size(struct xfs_attr_leafblock *leafp) 716 { 717 if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC)) 718 return sizeof(struct xfs_attr3_leaf_hdr); 719 return sizeof(struct xfs_attr_leaf_hdr); 720 } 721 722 static inline struct xfs_attr_leaf_entry * 723 xfs_attr3_leaf_entryp(xfs_attr_leafblock_t *leafp) 724 { 725 if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC)) 726 return &((struct xfs_attr3_leafblock *)leafp)->entries[0]; 727 return &leafp->entries[0]; 728 } 729 730 /* 731 * Cast typed pointers for "local" and "remote" name/value structs. 732 */ 733 static inline char * 734 xfs_attr3_leaf_name(xfs_attr_leafblock_t *leafp, int idx) 735 { 736 struct xfs_attr_leaf_entry *entries = xfs_attr3_leaf_entryp(leafp); 737 738 return &((char *)leafp)[be16_to_cpu(entries[idx].nameidx)]; 739 } 740 741 static inline xfs_attr_leaf_name_remote_t * 742 xfs_attr3_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx) 743 { 744 return (xfs_attr_leaf_name_remote_t *)xfs_attr3_leaf_name(leafp, idx); 745 } 746 747 static inline xfs_attr_leaf_name_local_t * 748 xfs_attr3_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx) 749 { 750 return (xfs_attr_leaf_name_local_t *)xfs_attr3_leaf_name(leafp, idx); 751 } 752 753 /* 754 * Calculate total bytes used (including trailing pad for alignment) for 755 * a "local" name/value structure, a "remote" name/value structure, and 756 * a pointer which might be either. 757 */ 758 static inline int xfs_attr_leaf_entsize_remote(int nlen) 759 { 760 /* 761 * Prior to Linux 6.5, struct xfs_attr_leaf_name_remote ended with 762 * name[1], which was used as a flexarray. The layout of this struct 763 * is 9 bytes of fixed-length fields followed by a __u8 flex array at 764 * offset 9. 765 * 766 * On most architectures, struct xfs_attr_leaf_name_remote had two 767 * bytes of implicit padding at the end of the struct to make the 768 * struct length 12. After converting name[1] to name[], there are 769 * three implicit padding bytes and the struct size remains 12. 770 * However, there are compiler configurations that do not add implicit 771 * padding at all (m68k) and have been broken for years. 772 * 773 * This entsize computation historically added (the xattr name length) 774 * to (the padded struct length - 1) and rounded that sum up to the 775 * nearest multiple of 4 (NAME_ALIGN). IOWs, round_up(11 + nlen, 4). 776 * This is encoded in the ondisk format, so we cannot change this. 777 * 778 * Compute the entsize from offsetof of the flexarray and manually 779 * adding bytes for the implicit padding. 780 */ 781 const size_t remotesize = 782 offsetof(struct xfs_attr_leaf_name_remote, name) + 2; 783 784 return round_up(remotesize + nlen, XFS_ATTR_LEAF_NAME_ALIGN); 785 } 786 787 static inline int xfs_attr_leaf_entsize_local(int nlen, int vlen) 788 { 789 /* 790 * Prior to Linux 6.5, struct xfs_attr_leaf_name_local ended with 791 * nameval[1], which was used as a flexarray. The layout of this 792 * struct is 3 bytes of fixed-length fields followed by a __u8 flex 793 * array at offset 3. 794 * 795 * struct xfs_attr_leaf_name_local had zero bytes of implicit padding 796 * at the end of the struct to make the struct length 4. On most 797 * architectures, after converting nameval[1] to nameval[], there is 798 * one implicit padding byte and the struct size remains 4. However, 799 * there are compiler configurations that do not add implicit padding 800 * at all (m68k) and would break. 801 * 802 * This entsize computation historically added (the xattr name and 803 * value length) to (the padded struct length - 1) and rounded that sum 804 * up to the nearest multiple of 4 (NAME_ALIGN). IOWs, the formula is 805 * round_up(3 + nlen + vlen, 4). This is encoded in the ondisk format, 806 * so we cannot change this. 807 * 808 * Compute the entsize from offsetof of the flexarray and manually 809 * adding bytes for the implicit padding. 810 */ 811 const size_t localsize = 812 offsetof(struct xfs_attr_leaf_name_local, nameval); 813 814 return round_up(localsize + nlen + vlen, XFS_ATTR_LEAF_NAME_ALIGN); 815 } 816 817 static inline int xfs_attr_leaf_entsize_local_max(int bsize) 818 { 819 return (((bsize) >> 1) + ((bsize) >> 2)); 820 } 821 822 823 824 /* 825 * Remote attribute block format definition 826 * 827 * There is one of these headers per filesystem block in a remote attribute. 828 * This is done to ensure there is a 1:1 mapping between the attribute value 829 * length and the number of blocks needed to store the attribute. This makes the 830 * verification of a buffer a little more complex, but greatly simplifies the 831 * allocation, reading and writing of these attributes as we don't have to guess 832 * the number of blocks needed to store the attribute data. 833 */ 834 #define XFS_ATTR3_RMT_MAGIC 0x5841524d /* XARM */ 835 836 struct xfs_attr3_rmt_hdr { 837 __be32 rm_magic; 838 __be32 rm_offset; 839 __be32 rm_bytes; 840 __be32 rm_crc; 841 uuid_t rm_uuid; 842 __be64 rm_owner; 843 __be64 rm_blkno; 844 __be64 rm_lsn; 845 }; 846 847 #define XFS_ATTR3_RMT_CRC_OFF offsetof(struct xfs_attr3_rmt_hdr, rm_crc) 848 849 #define XFS_ATTR3_RMT_BUF_SPACE(mp, bufsize) \ 850 ((bufsize) - (xfs_has_crc((mp)) ? \ 851 sizeof(struct xfs_attr3_rmt_hdr) : 0)) 852 853 /* Number of bytes in a directory block. */ 854 static inline unsigned int xfs_dir2_dirblock_bytes(struct xfs_sb *sbp) 855 { 856 return 1 << (sbp->sb_blocklog + sbp->sb_dirblklog); 857 } 858 859 xfs_failaddr_t xfs_da3_blkinfo_verify(struct xfs_buf *bp, 860 struct xfs_da3_blkinfo *hdr3); 861 862 #endif /* __XFS_DA_FORMAT_H__ */ 863