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 #define XFS_DIR3_FTYPE_STR \ 163 { XFS_DIR3_FT_UNKNOWN, "unknown" }, \ 164 { XFS_DIR3_FT_REG_FILE, "file" }, \ 165 { XFS_DIR3_FT_DIR, "directory" }, \ 166 { XFS_DIR3_FT_CHRDEV, "char" }, \ 167 { XFS_DIR3_FT_BLKDEV, "block" }, \ 168 { XFS_DIR3_FT_FIFO, "fifo" }, \ 169 { XFS_DIR3_FT_SOCK, "sock" }, \ 170 { XFS_DIR3_FT_SYMLINK, "symlink" }, \ 171 { XFS_DIR3_FT_WHT, "whiteout" } 172 173 /* 174 * Byte offset in data block and shortform entry. 175 */ 176 typedef uint16_t xfs_dir2_data_off_t; 177 #define NULLDATAOFF 0xffffU 178 typedef uint xfs_dir2_data_aoff_t; /* argument form */ 179 180 /* 181 * Offset in data space of a data entry. 182 */ 183 typedef uint32_t xfs_dir2_dataptr_t; 184 #define XFS_DIR2_MAX_DATAPTR ((xfs_dir2_dataptr_t)0xffffffff) 185 #define XFS_DIR2_NULL_DATAPTR ((xfs_dir2_dataptr_t)0) 186 187 /* 188 * Byte offset in a directory. 189 */ 190 typedef xfs_off_t xfs_dir2_off_t; 191 192 /* 193 * Directory block number (logical dirblk in file) 194 */ 195 typedef uint32_t xfs_dir2_db_t; 196 197 #define XFS_INO32_SIZE 4 198 #define XFS_INO64_SIZE 8 199 #define XFS_INO64_DIFF (XFS_INO64_SIZE - XFS_INO32_SIZE) 200 201 #define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL) 202 203 /* 204 * Directory layout when stored internal to an inode. 205 * 206 * Small directories are packed as tightly as possible so as to fit into the 207 * literal area of the inode. These "shortform" directories consist of a 208 * single xfs_dir2_sf_hdr header followed by zero or more xfs_dir2_sf_entry 209 * structures. Due the different inode number storage size and the variable 210 * length name field in the xfs_dir2_sf_entry all these structure are 211 * variable length, and the accessors in this file should be used to iterate 212 * over them. 213 */ 214 typedef struct xfs_dir2_sf_hdr { 215 uint8_t count; /* count of entries */ 216 uint8_t i8count; /* count of 8-byte inode #s */ 217 uint8_t parent[8]; /* parent dir inode number */ 218 } __packed xfs_dir2_sf_hdr_t; 219 220 typedef struct xfs_dir2_sf_entry { 221 __u8 namelen; /* actual name length */ 222 __u8 offset[2]; /* saved offset */ 223 __u8 name[]; /* name, variable size */ 224 /* 225 * A single byte containing the file type field follows the inode 226 * number for version 3 directory entries. 227 * 228 * A 64-bit or 32-bit inode number follows here, at a variable offset 229 * after the name. 230 */ 231 } __packed xfs_dir2_sf_entry_t; 232 233 static inline int xfs_dir2_sf_hdr_size(int i8count) 234 { 235 return sizeof(struct xfs_dir2_sf_hdr) - 236 (i8count == 0) * XFS_INO64_DIFF; 237 } 238 239 static inline xfs_dir2_data_aoff_t 240 xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep) 241 { 242 return get_unaligned_be16(sfep->offset); 243 } 244 245 static inline void 246 xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off) 247 { 248 put_unaligned_be16(off, sfep->offset); 249 } 250 251 static inline struct xfs_dir2_sf_entry * 252 xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr) 253 { 254 return (struct xfs_dir2_sf_entry *) 255 ((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count)); 256 } 257 258 /* 259 * Data block structures. 260 * 261 * A pure data block looks like the following drawing on disk: 262 * 263 * +-------------------------------------------------+ 264 * | xfs_dir2_data_hdr_t | 265 * +-------------------------------------------------+ 266 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | 267 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | 268 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | 269 * | ... | 270 * +-------------------------------------------------+ 271 * | unused space | 272 * +-------------------------------------------------+ 273 * 274 * As all the entries are variable size structures the accessors below should 275 * be used to iterate over them. 276 * 277 * In addition to the pure data blocks for the data and node formats, 278 * most structures are also used for the combined data/freespace "block" 279 * format below. 280 */ 281 282 #define XFS_DIR2_DATA_ALIGN_LOG 3 /* i.e., 8 bytes */ 283 #define XFS_DIR2_DATA_ALIGN (1 << XFS_DIR2_DATA_ALIGN_LOG) 284 #define XFS_DIR2_DATA_FREE_TAG 0xffff 285 #define XFS_DIR2_DATA_FD_COUNT 3 286 287 /* 288 * Directory address space divided into sections, 289 * spaces separated by 32GB. 290 */ 291 #define XFS_DIR2_MAX_SPACES 3 292 #define XFS_DIR2_SPACE_SIZE (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG)) 293 #define XFS_DIR2_DATA_SPACE 0 294 #define XFS_DIR2_DATA_OFFSET (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE) 295 296 /* 297 * Describe a free area in the data block. 298 * 299 * The freespace will be formatted as a xfs_dir2_data_unused_t. 300 */ 301 typedef struct xfs_dir2_data_free { 302 __be16 offset; /* start of freespace */ 303 __be16 length; /* length of freespace */ 304 } xfs_dir2_data_free_t; 305 306 /* 307 * Header for the data blocks. 308 * 309 * The code knows that XFS_DIR2_DATA_FD_COUNT is 3. 310 */ 311 typedef struct xfs_dir2_data_hdr { 312 __be32 magic; /* XFS_DIR2_DATA_MAGIC or */ 313 /* XFS_DIR2_BLOCK_MAGIC */ 314 xfs_dir2_data_free_t bestfree[XFS_DIR2_DATA_FD_COUNT]; 315 } xfs_dir2_data_hdr_t; 316 317 /* 318 * define a structure for all the verification fields we are adding to the 319 * directory block structures. This will be used in several structures. 320 * The magic number must be the first entry to align with all the dir2 321 * structures so we determine how to decode them just by the magic number. 322 */ 323 struct xfs_dir3_blk_hdr { 324 __be32 magic; /* magic number */ 325 __be32 crc; /* CRC of block */ 326 __be64 blkno; /* first block of the buffer */ 327 __be64 lsn; /* sequence number of last write */ 328 uuid_t uuid; /* filesystem we belong to */ 329 __be64 owner; /* inode that owns the block */ 330 }; 331 332 struct xfs_dir3_data_hdr { 333 struct xfs_dir3_blk_hdr hdr; 334 xfs_dir2_data_free_t best_free[XFS_DIR2_DATA_FD_COUNT]; 335 __be32 pad; /* 64 bit alignment */ 336 }; 337 338 #define XFS_DIR3_DATA_CRC_OFF offsetof(struct xfs_dir3_data_hdr, hdr.crc) 339 340 /* 341 * Active entry in a data block. 342 * 343 * Aligned to 8 bytes. After the variable length name field there is a 344 * 2 byte tag field, which can be accessed using xfs_dir3_data_entry_tag_p. 345 * 346 * For dir3 structures, there is file type field between the name and the tag. 347 * This can only be manipulated by helper functions. It is packed hard against 348 * the end of the name so any padding for rounding is between the file type and 349 * the tag. 350 */ 351 typedef struct xfs_dir2_data_entry { 352 __be64 inumber; /* inode number */ 353 __u8 namelen; /* name length */ 354 __u8 name[]; /* name bytes, no null */ 355 /* __u8 filetype; */ /* type of inode we point to */ 356 /* __be16 tag; */ /* starting offset of us */ 357 } xfs_dir2_data_entry_t; 358 359 /* 360 * Unused entry in a data block. 361 * 362 * Aligned to 8 bytes. Tag appears as the last 2 bytes and must be accessed 363 * using xfs_dir2_data_unused_tag_p. 364 */ 365 typedef struct xfs_dir2_data_unused { 366 __be16 freetag; /* XFS_DIR2_DATA_FREE_TAG */ 367 __be16 length; /* total free length */ 368 /* variable offset */ 369 __be16 tag; /* starting offset of us */ 370 } xfs_dir2_data_unused_t; 371 372 /* 373 * Pointer to a freespace's tag word. 374 */ 375 static inline __be16 * 376 xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup) 377 { 378 return (__be16 *)((char *)dup + 379 be16_to_cpu(dup->length) - sizeof(__be16)); 380 } 381 382 /* 383 * Leaf block structures. 384 * 385 * A pure leaf block looks like the following drawing on disk: 386 * 387 * +---------------------------+ 388 * | xfs_dir2_leaf_hdr_t | 389 * +---------------------------+ 390 * | xfs_dir2_leaf_entry_t | 391 * | xfs_dir2_leaf_entry_t | 392 * | xfs_dir2_leaf_entry_t | 393 * | xfs_dir2_leaf_entry_t | 394 * | ... | 395 * +---------------------------+ 396 * | xfs_dir2_data_off_t | 397 * | xfs_dir2_data_off_t | 398 * | xfs_dir2_data_off_t | 399 * | ... | 400 * +---------------------------+ 401 * | xfs_dir2_leaf_tail_t | 402 * +---------------------------+ 403 * 404 * The xfs_dir2_data_off_t members (bests) and tail are at the end of the block 405 * for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present 406 * for directories with separate leaf nodes and free space blocks 407 * (magic = XFS_DIR2_LEAFN_MAGIC). 408 * 409 * As all the entries are variable size structures the accessors below should 410 * be used to iterate over them. 411 */ 412 413 /* 414 * Offset of the leaf/node space. First block in this space 415 * is the btree root. 416 */ 417 #define XFS_DIR2_LEAF_SPACE 1 418 #define XFS_DIR2_LEAF_OFFSET (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE) 419 420 /* 421 * Leaf block header. 422 */ 423 typedef struct xfs_dir2_leaf_hdr { 424 xfs_da_blkinfo_t info; /* header for da routines */ 425 __be16 count; /* count of entries */ 426 __be16 stale; /* count of stale entries */ 427 } xfs_dir2_leaf_hdr_t; 428 429 struct xfs_dir3_leaf_hdr { 430 struct xfs_da3_blkinfo info; /* header for da routines */ 431 __be16 count; /* count of entries */ 432 __be16 stale; /* count of stale entries */ 433 __be32 pad; /* 64 bit alignment */ 434 }; 435 436 /* 437 * Leaf block entry. 438 */ 439 typedef struct xfs_dir2_leaf_entry { 440 __be32 hashval; /* hash value of name */ 441 __be32 address; /* address of data entry */ 442 } xfs_dir2_leaf_entry_t; 443 444 /* 445 * Leaf block tail. 446 */ 447 typedef struct xfs_dir2_leaf_tail { 448 __be32 bestcount; 449 } xfs_dir2_leaf_tail_t; 450 451 /* 452 * Leaf block. 453 */ 454 typedef struct xfs_dir2_leaf { 455 xfs_dir2_leaf_hdr_t hdr; /* leaf header */ 456 xfs_dir2_leaf_entry_t __ents[]; /* entries */ 457 } xfs_dir2_leaf_t; 458 459 struct xfs_dir3_leaf { 460 struct xfs_dir3_leaf_hdr hdr; /* leaf header */ 461 struct xfs_dir2_leaf_entry __ents[]; /* entries */ 462 }; 463 464 #define XFS_DIR3_LEAF_CRC_OFF offsetof(struct xfs_dir3_leaf_hdr, info.crc) 465 466 /* 467 * Get address of the bests array in the single-leaf block. 468 */ 469 static inline __be16 * 470 xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp) 471 { 472 return (__be16 *)ltp - be32_to_cpu(ltp->bestcount); 473 } 474 475 /* 476 * Free space block definitions for the node format. 477 */ 478 479 /* 480 * Offset of the freespace index. 481 */ 482 #define XFS_DIR2_FREE_SPACE 2 483 #define XFS_DIR2_FREE_OFFSET (XFS_DIR2_FREE_SPACE * XFS_DIR2_SPACE_SIZE) 484 485 typedef struct xfs_dir2_free_hdr { 486 __be32 magic; /* XFS_DIR2_FREE_MAGIC */ 487 __be32 firstdb; /* db of first entry */ 488 __be32 nvalid; /* count of valid entries */ 489 __be32 nused; /* count of used entries */ 490 } xfs_dir2_free_hdr_t; 491 492 typedef struct xfs_dir2_free { 493 xfs_dir2_free_hdr_t hdr; /* block header */ 494 __be16 bests[]; /* best free counts */ 495 /* unused entries are -1 */ 496 } xfs_dir2_free_t; 497 498 struct xfs_dir3_free_hdr { 499 struct xfs_dir3_blk_hdr hdr; 500 __be32 firstdb; /* db of first entry */ 501 __be32 nvalid; /* count of valid entries */ 502 __be32 nused; /* count of used entries */ 503 __be32 pad; /* 64 bit alignment */ 504 }; 505 506 struct xfs_dir3_free { 507 struct xfs_dir3_free_hdr hdr; 508 __be16 bests[]; /* best free counts */ 509 /* unused entries are -1 */ 510 }; 511 512 #define XFS_DIR3_FREE_CRC_OFF offsetof(struct xfs_dir3_free, hdr.hdr.crc) 513 514 /* 515 * Single block format. 516 * 517 * The single block format looks like the following drawing on disk: 518 * 519 * +-------------------------------------------------+ 520 * | xfs_dir2_data_hdr_t | 521 * +-------------------------------------------------+ 522 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | 523 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t | 524 * | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t : 525 * | ... | 526 * +-------------------------------------------------+ 527 * | unused space | 528 * +-------------------------------------------------+ 529 * | ... | 530 * | xfs_dir2_leaf_entry_t | 531 * | xfs_dir2_leaf_entry_t | 532 * +-------------------------------------------------+ 533 * | xfs_dir2_block_tail_t | 534 * +-------------------------------------------------+ 535 * 536 * As all the entries are variable size structures the accessors below should 537 * be used to iterate over them. 538 */ 539 540 typedef struct xfs_dir2_block_tail { 541 __be32 count; /* count of leaf entries */ 542 __be32 stale; /* count of stale lf entries */ 543 } xfs_dir2_block_tail_t; 544 545 /* 546 * Pointer to the leaf entries embedded in a data block (1-block format) 547 */ 548 static inline struct xfs_dir2_leaf_entry * 549 xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp) 550 { 551 return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count); 552 } 553 554 555 /* 556 * Attribute storage layout 557 * 558 * Attribute lists are structured around Btrees where all the data 559 * elements are in the leaf nodes. Attribute names are hashed into an int, 560 * then that int is used as the index into the Btree. Since the hashval 561 * of an attribute name may not be unique, we may have duplicate keys. The 562 * internal links in the Btree are logical block offsets into the file. 563 * 564 * Struct leaf_entry's are packed from the top. Name/values grow from the 565 * bottom but are not packed. The freemap contains run-length-encoded entries 566 * for the free bytes after the leaf_entry's, but only the N largest such, 567 * smaller runs are dropped. When the freemap doesn't show enough space 568 * for an allocation, we compact the name/value area and try again. If we 569 * still don't have enough space, then we have to split the block. The 570 * name/value structs (both local and remote versions) must be 32bit aligned. 571 * 572 * Since we have duplicate hash keys, for each key that matches, compare 573 * the actual name string. The root and intermediate node search always 574 * takes the first-in-the-block key match found, so we should only have 575 * to work "forw"ard. If none matches, continue with the "forw"ard leaf 576 * nodes until the hash key changes or the attribute name is found. 577 * 578 * We store the fact that an attribute is a ROOT/USER/SECURE attribute in 579 * the leaf_entry. The namespaces are independent only because we also look 580 * at the namespace bit when we are looking for a matching attribute name. 581 * 582 * We also store an "incomplete" bit in the leaf_entry. It shows that an 583 * attribute is in the middle of being created and should not be shown to 584 * the user if we crash during the time that the bit is set. We clear the 585 * bit when we have finished setting up the attribute. We do this because 586 * we cannot create some large attributes inside a single transaction, and we 587 * need some indication that we weren't finished if we crash in the middle. 588 */ 589 #define XFS_ATTR_LEAF_MAPSIZE 3 /* how many freespace slots */ 590 591 /* 592 * Attribute storage when stored inside the inode. 593 * 594 * Small attribute lists are packed as tightly as possible so as to fit into the 595 * literal area of the inode. 596 * 597 * These "shortform" attribute forks consist of a single xfs_attr_sf_hdr header 598 * followed by zero or more xfs_attr_sf_entry structures. 599 */ 600 struct xfs_attr_sf_hdr { /* constant-structure header block */ 601 __be16 totsize; /* total bytes in shortform list */ 602 __u8 count; /* count of active entries */ 603 __u8 padding; 604 }; 605 606 struct xfs_attr_sf_entry { 607 __u8 namelen; /* actual length of name (no NULL) */ 608 __u8 valuelen; /* actual length of value (no NULL) */ 609 __u8 flags; /* flags bits (XFS_ATTR_*) */ 610 __u8 nameval[]; /* name & value bytes concatenated */ 611 }; 612 613 typedef struct xfs_attr_leaf_map { /* RLE map of free bytes */ 614 __be16 base; /* base of free region */ 615 __be16 size; /* length of free region */ 616 } xfs_attr_leaf_map_t; 617 618 typedef struct xfs_attr_leaf_hdr { /* constant-structure header block */ 619 xfs_da_blkinfo_t info; /* block type, links, etc. */ 620 __be16 count; /* count of active leaf_entry's */ 621 __be16 usedbytes; /* num bytes of names/values stored */ 622 __be16 firstused; /* first used byte in name area */ 623 __u8 holes; /* != 0 if blk needs compaction */ 624 __u8 pad1; 625 xfs_attr_leaf_map_t freemap[XFS_ATTR_LEAF_MAPSIZE]; 626 /* N largest free regions */ 627 } xfs_attr_leaf_hdr_t; 628 629 typedef struct xfs_attr_leaf_entry { /* sorted on key, not name */ 630 __be32 hashval; /* hash value of name */ 631 __be16 nameidx; /* index into buffer of name/value */ 632 __u8 flags; /* LOCAL/ROOT/SECURE/INCOMPLETE flag */ 633 __u8 pad2; /* unused pad byte */ 634 } xfs_attr_leaf_entry_t; 635 636 typedef struct xfs_attr_leaf_name_local { 637 __be16 valuelen; /* number of bytes in value */ 638 __u8 namelen; /* length of name bytes */ 639 /* 640 * In Linux 6.5 this flex array was converted from nameval[1] to 641 * nameval[]. Be very careful here about extra padding at the end; 642 * see xfs_attr_leaf_entsize_local() for details. 643 */ 644 __u8 nameval[]; /* name/value bytes */ 645 } xfs_attr_leaf_name_local_t; 646 647 typedef struct xfs_attr_leaf_name_remote { 648 __be32 valueblk; /* block number of value bytes */ 649 __be32 valuelen; /* number of bytes in value */ 650 __u8 namelen; /* length of name bytes */ 651 /* 652 * In Linux 6.5 this flex array was converted from name[1] to name[]. 653 * Be very careful here about extra padding at the end; see 654 * xfs_attr_leaf_entsize_remote() for details. 655 */ 656 __u8 name[]; /* name bytes */ 657 } xfs_attr_leaf_name_remote_t; 658 659 typedef struct xfs_attr_leafblock { 660 xfs_attr_leaf_hdr_t hdr; /* constant-structure header block */ 661 xfs_attr_leaf_entry_t entries[]; /* sorted on key, not name */ 662 /* 663 * The rest of the block contains the following structures after the 664 * leaf entries, growing from the bottom up. The variables are never 665 * referenced and definining them can actually make gcc optimize away 666 * accesses to the 'entries' array above index 0 so don't do that. 667 * 668 * xfs_attr_leaf_name_local_t namelist; 669 * xfs_attr_leaf_name_remote_t valuelist; 670 */ 671 } xfs_attr_leafblock_t; 672 673 /* 674 * CRC enabled leaf structures. Called "version 3" structures to match the 675 * version number of the directory and dablk structures for this feature, and 676 * attr2 is already taken by the variable inode attribute fork size feature. 677 */ 678 struct xfs_attr3_leaf_hdr { 679 struct xfs_da3_blkinfo info; 680 __be16 count; 681 __be16 usedbytes; 682 __be16 firstused; 683 __u8 holes; 684 __u8 pad1; 685 struct xfs_attr_leaf_map freemap[XFS_ATTR_LEAF_MAPSIZE]; 686 __be32 pad2; /* 64 bit alignment */ 687 }; 688 689 #define XFS_ATTR3_LEAF_CRC_OFF (offsetof(struct xfs_attr3_leaf_hdr, info.crc)) 690 691 struct xfs_attr3_leafblock { 692 struct xfs_attr3_leaf_hdr hdr; 693 struct xfs_attr_leaf_entry entries[]; 694 695 /* 696 * The rest of the block contains the following structures after the 697 * leaf entries, growing from the bottom up. The variables are never 698 * referenced, the locations accessed purely from helper functions. 699 * 700 * struct xfs_attr_leaf_name_local 701 * struct xfs_attr_leaf_name_remote 702 */ 703 }; 704 705 /* 706 * Special value to represent fs block size in the leaf header firstused field. 707 * Only used when block size overflows the 2-bytes available on disk. 708 */ 709 #define XFS_ATTR3_LEAF_NULLOFF 0 710 711 /* 712 * Flags used in the leaf_entry[i].flags field. 713 */ 714 #define XFS_ATTR_LOCAL_BIT 0 /* attr is stored locally */ 715 #define XFS_ATTR_ROOT_BIT 1 /* limit access to trusted attrs */ 716 #define XFS_ATTR_SECURE_BIT 2 /* limit access to secure attrs */ 717 #define XFS_ATTR_INCOMPLETE_BIT 7 /* attr in middle of create/delete */ 718 #define XFS_ATTR_LOCAL (1u << XFS_ATTR_LOCAL_BIT) 719 #define XFS_ATTR_ROOT (1u << XFS_ATTR_ROOT_BIT) 720 #define XFS_ATTR_SECURE (1u << XFS_ATTR_SECURE_BIT) 721 #define XFS_ATTR_INCOMPLETE (1u << XFS_ATTR_INCOMPLETE_BIT) 722 #define XFS_ATTR_NSP_ONDISK_MASK (XFS_ATTR_ROOT | XFS_ATTR_SECURE) 723 724 /* 725 * Alignment for namelist and valuelist entries (since they are mixed 726 * there can be only one alignment value) 727 */ 728 #define XFS_ATTR_LEAF_NAME_ALIGN ((uint)sizeof(xfs_dablk_t)) 729 730 static inline int 731 xfs_attr3_leaf_hdr_size(struct xfs_attr_leafblock *leafp) 732 { 733 if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC)) 734 return sizeof(struct xfs_attr3_leaf_hdr); 735 return sizeof(struct xfs_attr_leaf_hdr); 736 } 737 738 static inline struct xfs_attr_leaf_entry * 739 xfs_attr3_leaf_entryp(xfs_attr_leafblock_t *leafp) 740 { 741 if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC)) 742 return &((struct xfs_attr3_leafblock *)leafp)->entries[0]; 743 return &leafp->entries[0]; 744 } 745 746 /* 747 * Cast typed pointers for "local" and "remote" name/value structs. 748 */ 749 static inline char * 750 xfs_attr3_leaf_name(xfs_attr_leafblock_t *leafp, int idx) 751 { 752 struct xfs_attr_leaf_entry *entries = xfs_attr3_leaf_entryp(leafp); 753 754 return &((char *)leafp)[be16_to_cpu(entries[idx].nameidx)]; 755 } 756 757 static inline xfs_attr_leaf_name_remote_t * 758 xfs_attr3_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx) 759 { 760 return (xfs_attr_leaf_name_remote_t *)xfs_attr3_leaf_name(leafp, idx); 761 } 762 763 static inline xfs_attr_leaf_name_local_t * 764 xfs_attr3_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx) 765 { 766 return (xfs_attr_leaf_name_local_t *)xfs_attr3_leaf_name(leafp, idx); 767 } 768 769 /* 770 * Calculate total bytes used (including trailing pad for alignment) for 771 * a "local" name/value structure, a "remote" name/value structure, and 772 * a pointer which might be either. 773 */ 774 static inline int xfs_attr_leaf_entsize_remote(int nlen) 775 { 776 /* 777 * Prior to Linux 6.5, struct xfs_attr_leaf_name_remote ended with 778 * name[1], which was used as a flexarray. The layout of this struct 779 * is 9 bytes of fixed-length fields followed by a __u8 flex array at 780 * offset 9. 781 * 782 * On most architectures, struct xfs_attr_leaf_name_remote had two 783 * bytes of implicit padding at the end of the struct to make the 784 * struct length 12. After converting name[1] to name[], there are 785 * three implicit padding bytes and the struct size remains 12. 786 * However, there are compiler configurations that do not add implicit 787 * padding at all (m68k) and have been broken for years. 788 * 789 * This entsize computation historically added (the xattr name length) 790 * to (the padded struct length - 1) and rounded that sum up to the 791 * nearest multiple of 4 (NAME_ALIGN). IOWs, round_up(11 + nlen, 4). 792 * This is encoded in the ondisk format, so we cannot change this. 793 * 794 * Compute the entsize from offsetof of the flexarray and manually 795 * adding bytes for the implicit padding. 796 */ 797 const size_t remotesize = 798 offsetof(struct xfs_attr_leaf_name_remote, name) + 2; 799 800 return round_up(remotesize + nlen, XFS_ATTR_LEAF_NAME_ALIGN); 801 } 802 803 static inline int xfs_attr_leaf_entsize_local(int nlen, int vlen) 804 { 805 /* 806 * Prior to Linux 6.5, struct xfs_attr_leaf_name_local ended with 807 * nameval[1], which was used as a flexarray. The layout of this 808 * struct is 3 bytes of fixed-length fields followed by a __u8 flex 809 * array at offset 3. 810 * 811 * struct xfs_attr_leaf_name_local had zero bytes of implicit padding 812 * at the end of the struct to make the struct length 4. On most 813 * architectures, after converting nameval[1] to nameval[], there is 814 * one implicit padding byte and the struct size remains 4. However, 815 * there are compiler configurations that do not add implicit padding 816 * at all (m68k) and would break. 817 * 818 * This entsize computation historically added (the xattr name and 819 * value length) to (the padded struct length - 1) and rounded that sum 820 * up to the nearest multiple of 4 (NAME_ALIGN). IOWs, the formula is 821 * round_up(3 + nlen + vlen, 4). This is encoded in the ondisk format, 822 * so we cannot change this. 823 * 824 * Compute the entsize from offsetof of the flexarray and manually 825 * adding bytes for the implicit padding. 826 */ 827 const size_t localsize = 828 offsetof(struct xfs_attr_leaf_name_local, nameval); 829 830 return round_up(localsize + nlen + vlen, XFS_ATTR_LEAF_NAME_ALIGN); 831 } 832 833 static inline int xfs_attr_leaf_entsize_local_max(int bsize) 834 { 835 return (((bsize) >> 1) + ((bsize) >> 2)); 836 } 837 838 839 840 /* 841 * Remote attribute block format definition 842 * 843 * There is one of these headers per filesystem block in a remote attribute. 844 * This is done to ensure there is a 1:1 mapping between the attribute value 845 * length and the number of blocks needed to store the attribute. This makes the 846 * verification of a buffer a little more complex, but greatly simplifies the 847 * allocation, reading and writing of these attributes as we don't have to guess 848 * the number of blocks needed to store the attribute data. 849 */ 850 #define XFS_ATTR3_RMT_MAGIC 0x5841524d /* XARM */ 851 852 struct xfs_attr3_rmt_hdr { 853 __be32 rm_magic; 854 __be32 rm_offset; 855 __be32 rm_bytes; 856 __be32 rm_crc; 857 uuid_t rm_uuid; 858 __be64 rm_owner; 859 __be64 rm_blkno; 860 __be64 rm_lsn; 861 }; 862 863 #define XFS_ATTR3_RMT_CRC_OFF offsetof(struct xfs_attr3_rmt_hdr, rm_crc) 864 865 #define XFS_ATTR3_RMT_BUF_SPACE(mp, bufsize) \ 866 ((bufsize) - (xfs_has_crc((mp)) ? \ 867 sizeof(struct xfs_attr3_rmt_hdr) : 0)) 868 869 /* Number of bytes in a directory block. */ 870 static inline unsigned int xfs_dir2_dirblock_bytes(struct xfs_sb *sbp) 871 { 872 return 1 << (sbp->sb_blocklog + sbp->sb_dirblklog); 873 } 874 875 xfs_failaddr_t xfs_da3_blkinfo_verify(struct xfs_buf *bp, 876 struct xfs_da3_blkinfo *hdr3); 877 878 #endif /* __XFS_DA_FORMAT_H__ */ 879