root/fs/xfs/libxfs/xfs_da_format.h

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INCLUDED FROM


DEFINITIONS

This source file includes following definitions.
  1. xfs_dir2_sf_hdr_size
  2. xfs_dir2_sf_get_offset
  3. xfs_dir2_sf_put_offset
  4. xfs_dir2_sf_firstentry
  5. xfs_dir2_data_unused_tag_p
  6. xfs_dir2_leaf_bests_p
  7. xfs_dir2_block_leaf_p
  8. xfs_attr3_leaf_hdr_size
  9. xfs_attr3_leaf_entryp
  10. xfs_attr3_leaf_name
  11. xfs_attr3_leaf_name_remote
  12. xfs_attr3_leaf_name_local
  13. xfs_attr_leaf_entsize_remote
  14. xfs_attr_leaf_entsize_local
  15. xfs_attr_leaf_entsize_local_max

   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: v2 dirlf single blks */
  39 #define XFS_DIR3_LEAFN_MAGIC    0x3dff  /* magic number: v2 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  * In-core version of the node header to abstract the differences in the v2 and
  98  * v3 disk format of the headers. Callers need to convert to/from disk format as
  99  * appropriate.
 100  */
 101 struct xfs_da3_icnode_hdr {
 102         uint32_t        forw;
 103         uint32_t        back;
 104         uint16_t        magic;
 105         uint16_t        count;
 106         uint16_t        level;
 107 };
 108 
 109 /*
 110  * Directory version 2.
 111  *
 112  * There are 4 possible formats:
 113  *  - shortform - embedded into the inode
 114  *  - single block - data with embedded leaf at the end
 115  *  - multiple data blocks, single leaf+freeindex block
 116  *  - data blocks, node and leaf blocks (btree), freeindex blocks
 117  *
 118  * Note: many node blocks structures and constants are shared with the attr
 119  * code and defined in xfs_da_btree.h.
 120  */
 121 
 122 #define XFS_DIR2_BLOCK_MAGIC    0x58443242      /* XD2B: single block dirs */
 123 #define XFS_DIR2_DATA_MAGIC     0x58443244      /* XD2D: multiblock dirs */
 124 #define XFS_DIR2_FREE_MAGIC     0x58443246      /* XD2F: free index blocks */
 125 
 126 /*
 127  * Directory Version 3 With CRCs.
 128  *
 129  * The tree formats are the same as for version 2 directories.  The difference
 130  * is in the block header and dirent formats. In many cases the v3 structures
 131  * use v2 definitions as they are no different and this makes code sharing much
 132  * easier.
 133  *
 134  * Also, the xfs_dir3_*() functions handle both v2 and v3 formats - if the
 135  * format is v2 then they switch to the existing v2 code, or the format is v3
 136  * they implement the v3 functionality. This means the existing dir2 is a mix of
 137  * xfs_dir2/xfs_dir3 calls and functions. The xfs_dir3 functions are called
 138  * where there is a difference in the formats, otherwise the code is unchanged.
 139  *
 140  * Where it is possible, the code decides what to do based on the magic numbers
 141  * in the blocks rather than feature bits in the superblock. This means the code
 142  * is as independent of the external XFS code as possible as doesn't require
 143  * passing struct xfs_mount pointers into places where it isn't really
 144  * necessary.
 145  *
 146  * Version 3 includes:
 147  *
 148  *      - a larger block header for CRC and identification purposes and so the
 149  *      offsets of all the structures inside the blocks are different.
 150  *
 151  *      - new magic numbers to be able to detect the v2/v3 types on the fly.
 152  */
 153 
 154 #define XFS_DIR3_BLOCK_MAGIC    0x58444233      /* XDB3: single block dirs */
 155 #define XFS_DIR3_DATA_MAGIC     0x58444433      /* XDD3: multiblock dirs */
 156 #define XFS_DIR3_FREE_MAGIC     0x58444633      /* XDF3: free index blocks */
 157 
 158 /*
 159  * Dirents in version 3 directories have a file type field. Additions to this
 160  * list are an on-disk format change, requiring feature bits. Valid values
 161  * are as follows:
 162  */
 163 #define XFS_DIR3_FT_UNKNOWN             0
 164 #define XFS_DIR3_FT_REG_FILE            1
 165 #define XFS_DIR3_FT_DIR                 2
 166 #define XFS_DIR3_FT_CHRDEV              3
 167 #define XFS_DIR3_FT_BLKDEV              4
 168 #define XFS_DIR3_FT_FIFO                5
 169 #define XFS_DIR3_FT_SOCK                6
 170 #define XFS_DIR3_FT_SYMLINK             7
 171 #define XFS_DIR3_FT_WHT                 8
 172 
 173 #define XFS_DIR3_FT_MAX                 9
 174 
 175 /*
 176  * Byte offset in data block and shortform entry.
 177  */
 178 typedef uint16_t        xfs_dir2_data_off_t;
 179 #define NULLDATAOFF     0xffffU
 180 typedef uint            xfs_dir2_data_aoff_t;   /* argument form */
 181 
 182 /*
 183  * Offset in data space of a data entry.
 184  */
 185 typedef uint32_t        xfs_dir2_dataptr_t;
 186 #define XFS_DIR2_MAX_DATAPTR    ((xfs_dir2_dataptr_t)0xffffffff)
 187 #define XFS_DIR2_NULL_DATAPTR   ((xfs_dir2_dataptr_t)0)
 188 
 189 /*
 190  * Byte offset in a directory.
 191  */
 192 typedef xfs_off_t       xfs_dir2_off_t;
 193 
 194 /*
 195  * Directory block number (logical dirblk in file)
 196  */
 197 typedef uint32_t        xfs_dir2_db_t;
 198 
 199 #define XFS_INO32_SIZE  4
 200 #define XFS_INO64_SIZE  8
 201 #define XFS_INO64_DIFF  (XFS_INO64_SIZE - XFS_INO32_SIZE)
 202 
 203 #define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL)
 204 
 205 /*
 206  * Directory layout when stored internal to an inode.
 207  *
 208  * Small directories are packed as tightly as possible so as to fit into the
 209  * literal area of the inode.  These "shortform" directories consist of a
 210  * single xfs_dir2_sf_hdr header followed by zero or more xfs_dir2_sf_entry
 211  * structures.  Due the different inode number storage size and the variable
 212  * length name field in the xfs_dir2_sf_entry all these structure are
 213  * variable length, and the accessors in this file should be used to iterate
 214  * over them.
 215  */
 216 typedef struct xfs_dir2_sf_hdr {
 217         uint8_t                 count;          /* count of entries */
 218         uint8_t                 i8count;        /* count of 8-byte inode #s */
 219         uint8_t                 parent[8];      /* parent dir inode number */
 220 } __packed xfs_dir2_sf_hdr_t;
 221 
 222 typedef struct xfs_dir2_sf_entry {
 223         __u8                    namelen;        /* actual name length */
 224         __u8                    offset[2];      /* saved offset */
 225         __u8                    name[];         /* name, variable size */
 226         /*
 227          * A single byte containing the file type field follows the inode
 228          * number for version 3 directory entries.
 229          *
 230          * A 64-bit or 32-bit inode number follows here, at a variable offset
 231          * after the name.
 232          */
 233 } xfs_dir2_sf_entry_t;
 234 
 235 static inline int xfs_dir2_sf_hdr_size(int i8count)
 236 {
 237         return sizeof(struct xfs_dir2_sf_hdr) -
 238                 (i8count == 0) * XFS_INO64_DIFF;
 239 }
 240 
 241 static inline xfs_dir2_data_aoff_t
 242 xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep)
 243 {
 244         return get_unaligned_be16(sfep->offset);
 245 }
 246 
 247 static inline void
 248 xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off)
 249 {
 250         put_unaligned_be16(off, sfep->offset);
 251 }
 252 
 253 static inline struct xfs_dir2_sf_entry *
 254 xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr)
 255 {
 256         return (struct xfs_dir2_sf_entry *)
 257                 ((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count));
 258 }
 259 
 260 /*
 261  * Data block structures.
 262  *
 263  * A pure data block looks like the following drawing on disk:
 264  *
 265  *    +-------------------------------------------------+
 266  *    | xfs_dir2_data_hdr_t                             |
 267  *    +-------------------------------------------------+
 268  *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 269  *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 270  *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 271  *    | ...                                             |
 272  *    +-------------------------------------------------+
 273  *    | unused space                                    |
 274  *    +-------------------------------------------------+
 275  *
 276  * As all the entries are variable size structures the accessors below should
 277  * be used to iterate over them.
 278  *
 279  * In addition to the pure data blocks for the data and node formats,
 280  * most structures are also used for the combined data/freespace "block"
 281  * format below.
 282  */
 283 
 284 #define XFS_DIR2_DATA_ALIGN_LOG 3               /* i.e., 8 bytes */
 285 #define XFS_DIR2_DATA_ALIGN     (1 << XFS_DIR2_DATA_ALIGN_LOG)
 286 #define XFS_DIR2_DATA_FREE_TAG  0xffff
 287 #define XFS_DIR2_DATA_FD_COUNT  3
 288 
 289 /*
 290  * Directory address space divided into sections,
 291  * spaces separated by 32GB.
 292  */
 293 #define XFS_DIR2_SPACE_SIZE     (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
 294 #define XFS_DIR2_DATA_SPACE     0
 295 #define XFS_DIR2_DATA_OFFSET    (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE)
 296 
 297 /*
 298  * Describe a free area in the data block.
 299  *
 300  * The freespace will be formatted as a xfs_dir2_data_unused_t.
 301  */
 302 typedef struct xfs_dir2_data_free {
 303         __be16                  offset;         /* start of freespace */
 304         __be16                  length;         /* length of freespace */
 305 } xfs_dir2_data_free_t;
 306 
 307 /*
 308  * Header for the data blocks.
 309  *
 310  * The code knows that XFS_DIR2_DATA_FD_COUNT is 3.
 311  */
 312 typedef struct xfs_dir2_data_hdr {
 313         __be32                  magic;          /* XFS_DIR2_DATA_MAGIC or */
 314                                                 /* XFS_DIR2_BLOCK_MAGIC */
 315         xfs_dir2_data_free_t    bestfree[XFS_DIR2_DATA_FD_COUNT];
 316 } xfs_dir2_data_hdr_t;
 317 
 318 /*
 319  * define a structure for all the verification fields we are adding to the
 320  * directory block structures. This will be used in several structures.
 321  * The magic number must be the first entry to align with all the dir2
 322  * structures so we determine how to decode them just by the magic number.
 323  */
 324 struct xfs_dir3_blk_hdr {
 325         __be32                  magic;  /* magic number */
 326         __be32                  crc;    /* CRC of block */
 327         __be64                  blkno;  /* first block of the buffer */
 328         __be64                  lsn;    /* sequence number of last write */
 329         uuid_t                  uuid;   /* filesystem we belong to */
 330         __be64                  owner;  /* inode that owns the block */
 331 };
 332 
 333 struct xfs_dir3_data_hdr {
 334         struct xfs_dir3_blk_hdr hdr;
 335         xfs_dir2_data_free_t    best_free[XFS_DIR2_DATA_FD_COUNT];
 336         __be32                  pad;    /* 64 bit alignment */
 337 };
 338 
 339 #define XFS_DIR3_DATA_CRC_OFF  offsetof(struct xfs_dir3_data_hdr, hdr.crc)
 340 
 341 /*
 342  * Active entry in a data block.
 343  *
 344  * Aligned to 8 bytes.  After the variable length name field there is a
 345  * 2 byte tag field, which can be accessed using xfs_dir3_data_entry_tag_p.
 346  *
 347  * For dir3 structures, there is file type field between the name and the tag.
 348  * This can only be manipulated by helper functions. It is packed hard against
 349  * the end of the name so any padding for rounding is between the file type and
 350  * the tag.
 351  */
 352 typedef struct xfs_dir2_data_entry {
 353         __be64                  inumber;        /* inode number */
 354         __u8                    namelen;        /* name length */
 355         __u8                    name[];         /* name bytes, no null */
 356      /* __u8                    filetype; */    /* type of inode we point to */
 357      /* __be16                  tag; */         /* starting offset of us */
 358 } xfs_dir2_data_entry_t;
 359 
 360 /*
 361  * Unused entry in a data block.
 362  *
 363  * Aligned to 8 bytes.  Tag appears as the last 2 bytes and must be accessed
 364  * using xfs_dir2_data_unused_tag_p.
 365  */
 366 typedef struct xfs_dir2_data_unused {
 367         __be16                  freetag;        /* XFS_DIR2_DATA_FREE_TAG */
 368         __be16                  length;         /* total free length */
 369                                                 /* variable offset */
 370         __be16                  tag;            /* starting offset of us */
 371 } xfs_dir2_data_unused_t;
 372 
 373 /*
 374  * Pointer to a freespace's tag word.
 375  */
 376 static inline __be16 *
 377 xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup)
 378 {
 379         return (__be16 *)((char *)dup +
 380                         be16_to_cpu(dup->length) - sizeof(__be16));
 381 }
 382 
 383 /*
 384  * Leaf block structures.
 385  *
 386  * A pure leaf block looks like the following drawing on disk:
 387  *
 388  *    +---------------------------+
 389  *    | xfs_dir2_leaf_hdr_t       |
 390  *    +---------------------------+
 391  *    | xfs_dir2_leaf_entry_t     |
 392  *    | xfs_dir2_leaf_entry_t     |
 393  *    | xfs_dir2_leaf_entry_t     |
 394  *    | xfs_dir2_leaf_entry_t     |
 395  *    | ...                       |
 396  *    +---------------------------+
 397  *    | xfs_dir2_data_off_t       |
 398  *    | xfs_dir2_data_off_t       |
 399  *    | xfs_dir2_data_off_t       |
 400  *    | ...                       |
 401  *    +---------------------------+
 402  *    | xfs_dir2_leaf_tail_t      |
 403  *    +---------------------------+
 404  *
 405  * The xfs_dir2_data_off_t members (bests) and tail are at the end of the block
 406  * for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present
 407  * for directories with separate leaf nodes and free space blocks
 408  * (magic = XFS_DIR2_LEAFN_MAGIC).
 409  *
 410  * As all the entries are variable size structures the accessors below should
 411  * be used to iterate over them.
 412  */
 413 
 414 /*
 415  * Offset of the leaf/node space.  First block in this space
 416  * is the btree root.
 417  */
 418 #define XFS_DIR2_LEAF_SPACE     1
 419 #define XFS_DIR2_LEAF_OFFSET    (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE)
 420 
 421 /*
 422  * Leaf block header.
 423  */
 424 typedef struct xfs_dir2_leaf_hdr {
 425         xfs_da_blkinfo_t        info;           /* header for da routines */
 426         __be16                  count;          /* count of entries */
 427         __be16                  stale;          /* count of stale entries */
 428 } xfs_dir2_leaf_hdr_t;
 429 
 430 struct xfs_dir3_leaf_hdr {
 431         struct xfs_da3_blkinfo  info;           /* header for da routines */
 432         __be16                  count;          /* count of entries */
 433         __be16                  stale;          /* count of stale entries */
 434         __be32                  pad;            /* 64 bit alignment */
 435 };
 436 
 437 struct xfs_dir3_icleaf_hdr {
 438         uint32_t                forw;
 439         uint32_t                back;
 440         uint16_t                magic;
 441         uint16_t                count;
 442         uint16_t                stale;
 443 };
 444 
 445 /*
 446  * Leaf block entry.
 447  */
 448 typedef struct xfs_dir2_leaf_entry {
 449         __be32                  hashval;        /* hash value of name */
 450         __be32                  address;        /* address of data entry */
 451 } xfs_dir2_leaf_entry_t;
 452 
 453 /*
 454  * Leaf block tail.
 455  */
 456 typedef struct xfs_dir2_leaf_tail {
 457         __be32                  bestcount;
 458 } xfs_dir2_leaf_tail_t;
 459 
 460 /*
 461  * Leaf block.
 462  */
 463 typedef struct xfs_dir2_leaf {
 464         xfs_dir2_leaf_hdr_t     hdr;                    /* leaf header */
 465         xfs_dir2_leaf_entry_t   __ents[];               /* entries */
 466 } xfs_dir2_leaf_t;
 467 
 468 struct xfs_dir3_leaf {
 469         struct xfs_dir3_leaf_hdr        hdr;            /* leaf header */
 470         struct xfs_dir2_leaf_entry      __ents[];       /* entries */
 471 };
 472 
 473 #define XFS_DIR3_LEAF_CRC_OFF  offsetof(struct xfs_dir3_leaf_hdr, info.crc)
 474 
 475 /*
 476  * Get address of the bests array in the single-leaf block.
 477  */
 478 static inline __be16 *
 479 xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp)
 480 {
 481         return (__be16 *)ltp - be32_to_cpu(ltp->bestcount);
 482 }
 483 
 484 /*
 485  * Free space block defintions for the node format.
 486  */
 487 
 488 /*
 489  * Offset of the freespace index.
 490  */
 491 #define XFS_DIR2_FREE_SPACE     2
 492 #define XFS_DIR2_FREE_OFFSET    (XFS_DIR2_FREE_SPACE * XFS_DIR2_SPACE_SIZE)
 493 
 494 typedef struct xfs_dir2_free_hdr {
 495         __be32                  magic;          /* XFS_DIR2_FREE_MAGIC */
 496         __be32                  firstdb;        /* db of first entry */
 497         __be32                  nvalid;         /* count of valid entries */
 498         __be32                  nused;          /* count of used entries */
 499 } xfs_dir2_free_hdr_t;
 500 
 501 typedef struct xfs_dir2_free {
 502         xfs_dir2_free_hdr_t     hdr;            /* block header */
 503         __be16                  bests[];        /* best free counts */
 504                                                 /* unused entries are -1 */
 505 } xfs_dir2_free_t;
 506 
 507 struct xfs_dir3_free_hdr {
 508         struct xfs_dir3_blk_hdr hdr;
 509         __be32                  firstdb;        /* db of first entry */
 510         __be32                  nvalid;         /* count of valid entries */
 511         __be32                  nused;          /* count of used entries */
 512         __be32                  pad;            /* 64 bit alignment */
 513 };
 514 
 515 struct xfs_dir3_free {
 516         struct xfs_dir3_free_hdr hdr;
 517         __be16                  bests[];        /* best free counts */
 518                                                 /* unused entries are -1 */
 519 };
 520 
 521 #define XFS_DIR3_FREE_CRC_OFF  offsetof(struct xfs_dir3_free, hdr.hdr.crc)
 522 
 523 /*
 524  * In core version of the free block header, abstracted away from on-disk format
 525  * differences. Use this in the code, and convert to/from the disk version using
 526  * xfs_dir3_free_hdr_from_disk/xfs_dir3_free_hdr_to_disk.
 527  */
 528 struct xfs_dir3_icfree_hdr {
 529         uint32_t        magic;
 530         uint32_t        firstdb;
 531         uint32_t        nvalid;
 532         uint32_t        nused;
 533 
 534 };
 535 
 536 /*
 537  * Single block format.
 538  *
 539  * The single block format looks like the following drawing on disk:
 540  *
 541  *    +-------------------------------------------------+
 542  *    | xfs_dir2_data_hdr_t                             |
 543  *    +-------------------------------------------------+
 544  *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 545  *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 546  *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t :
 547  *    | ...                                             |
 548  *    +-------------------------------------------------+
 549  *    | unused space                                    |
 550  *    +-------------------------------------------------+
 551  *    | ...                                             |
 552  *    | xfs_dir2_leaf_entry_t                           |
 553  *    | xfs_dir2_leaf_entry_t                           |
 554  *    +-------------------------------------------------+
 555  *    | xfs_dir2_block_tail_t                           |
 556  *    +-------------------------------------------------+
 557  *
 558  * As all the entries are variable size structures the accessors below should
 559  * be used to iterate over them.
 560  */
 561 
 562 typedef struct xfs_dir2_block_tail {
 563         __be32          count;                  /* count of leaf entries */
 564         __be32          stale;                  /* count of stale lf entries */
 565 } xfs_dir2_block_tail_t;
 566 
 567 /*
 568  * Pointer to the leaf entries embedded in a data block (1-block format)
 569  */
 570 static inline struct xfs_dir2_leaf_entry *
 571 xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp)
 572 {
 573         return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count);
 574 }
 575 
 576 
 577 /*
 578  * Attribute storage layout
 579  *
 580  * Attribute lists are structured around Btrees where all the data
 581  * elements are in the leaf nodes.  Attribute names are hashed into an int,
 582  * then that int is used as the index into the Btree.  Since the hashval
 583  * of an attribute name may not be unique, we may have duplicate keys.  The
 584  * internal links in the Btree are logical block offsets into the file.
 585  *
 586  * Struct leaf_entry's are packed from the top.  Name/values grow from the
 587  * bottom but are not packed.  The freemap contains run-length-encoded entries
 588  * for the free bytes after the leaf_entry's, but only the N largest such,
 589  * smaller runs are dropped.  When the freemap doesn't show enough space
 590  * for an allocation, we compact the name/value area and try again.  If we
 591  * still don't have enough space, then we have to split the block.  The
 592  * name/value structs (both local and remote versions) must be 32bit aligned.
 593  *
 594  * Since we have duplicate hash keys, for each key that matches, compare
 595  * the actual name string.  The root and intermediate node search always
 596  * takes the first-in-the-block key match found, so we should only have
 597  * to work "forw"ard.  If none matches, continue with the "forw"ard leaf
 598  * nodes until the hash key changes or the attribute name is found.
 599  *
 600  * We store the fact that an attribute is a ROOT/USER/SECURE attribute in
 601  * the leaf_entry.  The namespaces are independent only because we also look
 602  * at the namespace bit when we are looking for a matching attribute name.
 603  *
 604  * We also store an "incomplete" bit in the leaf_entry.  It shows that an
 605  * attribute is in the middle of being created and should not be shown to
 606  * the user if we crash during the time that the bit is set.  We clear the
 607  * bit when we have finished setting up the attribute.  We do this because
 608  * we cannot create some large attributes inside a single transaction, and we
 609  * need some indication that we weren't finished if we crash in the middle.
 610  */
 611 #define XFS_ATTR_LEAF_MAPSIZE   3       /* how many freespace slots */
 612 
 613 /*
 614  * Entries are packed toward the top as tight as possible.
 615  */
 616 typedef struct xfs_attr_shortform {
 617         struct xfs_attr_sf_hdr {        /* constant-structure header block */
 618                 __be16  totsize;        /* total bytes in shortform list */
 619                 __u8    count;  /* count of active entries */
 620                 __u8    padding;
 621         } hdr;
 622         struct xfs_attr_sf_entry {
 623                 uint8_t namelen;        /* actual length of name (no NULL) */
 624                 uint8_t valuelen;       /* actual length of value (no NULL) */
 625                 uint8_t flags;  /* flags bits (see xfs_attr_leaf.h) */
 626                 uint8_t nameval[1];     /* name & value bytes concatenated */
 627         } list[1];                      /* variable sized array */
 628 } xfs_attr_shortform_t;
 629 
 630 typedef struct xfs_attr_leaf_map {      /* RLE map of free bytes */
 631         __be16  base;                     /* base of free region */
 632         __be16  size;                     /* length of free region */
 633 } xfs_attr_leaf_map_t;
 634 
 635 typedef struct xfs_attr_leaf_hdr {      /* constant-structure header block */
 636         xfs_da_blkinfo_t info;          /* block type, links, etc. */
 637         __be16  count;                  /* count of active leaf_entry's */
 638         __be16  usedbytes;              /* num bytes of names/values stored */
 639         __be16  firstused;              /* first used byte in name area */
 640         __u8    holes;                  /* != 0 if blk needs compaction */
 641         __u8    pad1;
 642         xfs_attr_leaf_map_t freemap[XFS_ATTR_LEAF_MAPSIZE];
 643                                         /* N largest free regions */
 644 } xfs_attr_leaf_hdr_t;
 645 
 646 typedef struct xfs_attr_leaf_entry {    /* sorted on key, not name */
 647         __be32  hashval;                /* hash value of name */
 648         __be16  nameidx;                /* index into buffer of name/value */
 649         __u8    flags;                  /* LOCAL/ROOT/SECURE/INCOMPLETE flag */
 650         __u8    pad2;                   /* unused pad byte */
 651 } xfs_attr_leaf_entry_t;
 652 
 653 typedef struct xfs_attr_leaf_name_local {
 654         __be16  valuelen;               /* number of bytes in value */
 655         __u8    namelen;                /* length of name bytes */
 656         __u8    nameval[1];             /* name/value bytes */
 657 } xfs_attr_leaf_name_local_t;
 658 
 659 typedef struct xfs_attr_leaf_name_remote {
 660         __be32  valueblk;               /* block number of value bytes */
 661         __be32  valuelen;               /* number of bytes in value */
 662         __u8    namelen;                /* length of name bytes */
 663         __u8    name[1];                /* name bytes */
 664 } xfs_attr_leaf_name_remote_t;
 665 
 666 typedef struct xfs_attr_leafblock {
 667         xfs_attr_leaf_hdr_t     hdr;    /* constant-structure header block */
 668         xfs_attr_leaf_entry_t   entries[1];     /* sorted on key, not name */
 669         /*
 670          * The rest of the block contains the following structures after the
 671          * leaf entries, growing from the bottom up. The variables are never
 672          * referenced and definining them can actually make gcc optimize away
 673          * accesses to the 'entries' array above index 0 so don't do that.
 674          *
 675          * xfs_attr_leaf_name_local_t namelist;
 676          * xfs_attr_leaf_name_remote_t valuelist;
 677          */
 678 } xfs_attr_leafblock_t;
 679 
 680 /*
 681  * CRC enabled leaf structures. Called "version 3" structures to match the
 682  * version number of the directory and dablk structures for this feature, and
 683  * attr2 is already taken by the variable inode attribute fork size feature.
 684  */
 685 struct xfs_attr3_leaf_hdr {
 686         struct xfs_da3_blkinfo  info;
 687         __be16                  count;
 688         __be16                  usedbytes;
 689         __be16                  firstused;
 690         __u8                    holes;
 691         __u8                    pad1;
 692         struct xfs_attr_leaf_map freemap[XFS_ATTR_LEAF_MAPSIZE];
 693         __be32                  pad2;           /* 64 bit alignment */
 694 };
 695 
 696 #define XFS_ATTR3_LEAF_CRC_OFF  (offsetof(struct xfs_attr3_leaf_hdr, info.crc))
 697 
 698 struct xfs_attr3_leafblock {
 699         struct xfs_attr3_leaf_hdr       hdr;
 700         struct xfs_attr_leaf_entry      entries[1];
 701 
 702         /*
 703          * The rest of the block contains the following structures after the
 704          * leaf entries, growing from the bottom up. The variables are never
 705          * referenced, the locations accessed purely from helper functions.
 706          *
 707          * struct xfs_attr_leaf_name_local
 708          * struct xfs_attr_leaf_name_remote
 709          */
 710 };
 711 
 712 /*
 713  * incore, neutral version of the attribute leaf header
 714  */
 715 struct xfs_attr3_icleaf_hdr {
 716         uint32_t        forw;
 717         uint32_t        back;
 718         uint16_t        magic;
 719         uint16_t        count;
 720         uint16_t        usedbytes;
 721         /*
 722          * firstused is 32-bit here instead of 16-bit like the on-disk variant
 723          * to support maximum fsb size of 64k without overflow issues throughout
 724          * the attr code. Instead, the overflow condition is handled on
 725          * conversion to/from disk.
 726          */
 727         uint32_t        firstused;
 728         __u8            holes;
 729         struct {
 730                 uint16_t        base;
 731                 uint16_t        size;
 732         } freemap[XFS_ATTR_LEAF_MAPSIZE];
 733 };
 734 
 735 /*
 736  * Special value to represent fs block size in the leaf header firstused field.
 737  * Only used when block size overflows the 2-bytes available on disk.
 738  */
 739 #define XFS_ATTR3_LEAF_NULLOFF  0
 740 
 741 /*
 742  * Flags used in the leaf_entry[i].flags field.
 743  * NOTE: the INCOMPLETE bit must not collide with the flags bits specified
 744  * on the system call, they are "or"ed together for various operations.
 745  */
 746 #define XFS_ATTR_LOCAL_BIT      0       /* attr is stored locally */
 747 #define XFS_ATTR_ROOT_BIT       1       /* limit access to trusted attrs */
 748 #define XFS_ATTR_SECURE_BIT     2       /* limit access to secure attrs */
 749 #define XFS_ATTR_INCOMPLETE_BIT 7       /* attr in middle of create/delete */
 750 #define XFS_ATTR_LOCAL          (1 << XFS_ATTR_LOCAL_BIT)
 751 #define XFS_ATTR_ROOT           (1 << XFS_ATTR_ROOT_BIT)
 752 #define XFS_ATTR_SECURE         (1 << XFS_ATTR_SECURE_BIT)
 753 #define XFS_ATTR_INCOMPLETE     (1 << XFS_ATTR_INCOMPLETE_BIT)
 754 
 755 /*
 756  * Conversion macros for converting namespace bits from argument flags
 757  * to ondisk flags.
 758  */
 759 #define XFS_ATTR_NSP_ARGS_MASK          (ATTR_ROOT | ATTR_SECURE)
 760 #define XFS_ATTR_NSP_ONDISK_MASK        (XFS_ATTR_ROOT | XFS_ATTR_SECURE)
 761 #define XFS_ATTR_NSP_ONDISK(flags)      ((flags) & XFS_ATTR_NSP_ONDISK_MASK)
 762 #define XFS_ATTR_NSP_ARGS(flags)        ((flags) & XFS_ATTR_NSP_ARGS_MASK)
 763 #define XFS_ATTR_NSP_ARGS_TO_ONDISK(x)  (((x) & ATTR_ROOT ? XFS_ATTR_ROOT : 0) |\
 764                                          ((x) & ATTR_SECURE ? XFS_ATTR_SECURE : 0))
 765 #define XFS_ATTR_NSP_ONDISK_TO_ARGS(x)  (((x) & XFS_ATTR_ROOT ? ATTR_ROOT : 0) |\
 766                                          ((x) & XFS_ATTR_SECURE ? ATTR_SECURE : 0))
 767 
 768 /*
 769  * Alignment for namelist and valuelist entries (since they are mixed
 770  * there can be only one alignment value)
 771  */
 772 #define XFS_ATTR_LEAF_NAME_ALIGN        ((uint)sizeof(xfs_dablk_t))
 773 
 774 static inline int
 775 xfs_attr3_leaf_hdr_size(struct xfs_attr_leafblock *leafp)
 776 {
 777         if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC))
 778                 return sizeof(struct xfs_attr3_leaf_hdr);
 779         return sizeof(struct xfs_attr_leaf_hdr);
 780 }
 781 
 782 static inline struct xfs_attr_leaf_entry *
 783 xfs_attr3_leaf_entryp(xfs_attr_leafblock_t *leafp)
 784 {
 785         if (leafp->hdr.info.magic == cpu_to_be16(XFS_ATTR3_LEAF_MAGIC))
 786                 return &((struct xfs_attr3_leafblock *)leafp)->entries[0];
 787         return &leafp->entries[0];
 788 }
 789 
 790 /*
 791  * Cast typed pointers for "local" and "remote" name/value structs.
 792  */
 793 static inline char *
 794 xfs_attr3_leaf_name(xfs_attr_leafblock_t *leafp, int idx)
 795 {
 796         struct xfs_attr_leaf_entry *entries = xfs_attr3_leaf_entryp(leafp);
 797 
 798         return &((char *)leafp)[be16_to_cpu(entries[idx].nameidx)];
 799 }
 800 
 801 static inline xfs_attr_leaf_name_remote_t *
 802 xfs_attr3_leaf_name_remote(xfs_attr_leafblock_t *leafp, int idx)
 803 {
 804         return (xfs_attr_leaf_name_remote_t *)xfs_attr3_leaf_name(leafp, idx);
 805 }
 806 
 807 static inline xfs_attr_leaf_name_local_t *
 808 xfs_attr3_leaf_name_local(xfs_attr_leafblock_t *leafp, int idx)
 809 {
 810         return (xfs_attr_leaf_name_local_t *)xfs_attr3_leaf_name(leafp, idx);
 811 }
 812 
 813 /*
 814  * Calculate total bytes used (including trailing pad for alignment) for
 815  * a "local" name/value structure, a "remote" name/value structure, and
 816  * a pointer which might be either.
 817  */
 818 static inline int xfs_attr_leaf_entsize_remote(int nlen)
 819 {
 820         return ((uint)sizeof(xfs_attr_leaf_name_remote_t) - 1 + (nlen) + \
 821                 XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1);
 822 }
 823 
 824 static inline int xfs_attr_leaf_entsize_local(int nlen, int vlen)
 825 {
 826         return ((uint)sizeof(xfs_attr_leaf_name_local_t) - 1 + (nlen) + (vlen) +
 827                 XFS_ATTR_LEAF_NAME_ALIGN - 1) & ~(XFS_ATTR_LEAF_NAME_ALIGN - 1);
 828 }
 829 
 830 static inline int xfs_attr_leaf_entsize_local_max(int bsize)
 831 {
 832         return (((bsize) >> 1) + ((bsize) >> 2));
 833 }
 834 
 835 
 836 
 837 /*
 838  * Remote attribute block format definition
 839  *
 840  * There is one of these headers per filesystem block in a remote attribute.
 841  * This is done to ensure there is a 1:1 mapping between the attribute value
 842  * length and the number of blocks needed to store the attribute. This makes the
 843  * verification of a buffer a little more complex, but greatly simplifies the
 844  * allocation, reading and writing of these attributes as we don't have to guess
 845  * the number of blocks needed to store the attribute data.
 846  */
 847 #define XFS_ATTR3_RMT_MAGIC     0x5841524d      /* XARM */
 848 
 849 struct xfs_attr3_rmt_hdr {
 850         __be32  rm_magic;
 851         __be32  rm_offset;
 852         __be32  rm_bytes;
 853         __be32  rm_crc;
 854         uuid_t  rm_uuid;
 855         __be64  rm_owner;
 856         __be64  rm_blkno;
 857         __be64  rm_lsn;
 858 };
 859 
 860 #define XFS_ATTR3_RMT_CRC_OFF   offsetof(struct xfs_attr3_rmt_hdr, rm_crc)
 861 
 862 #define XFS_ATTR3_RMT_BUF_SPACE(mp, bufsize)    \
 863         ((bufsize) - (xfs_sb_version_hascrc(&(mp)->m_sb) ? \
 864                         sizeof(struct xfs_attr3_rmt_hdr) : 0))
 865 
 866 /* Number of bytes in a directory block. */
 867 static inline unsigned int xfs_dir2_dirblock_bytes(struct xfs_sb *sbp)
 868 {
 869         return 1 << (sbp->sb_blocklog + sbp->sb_dirblklog);
 870 }
 871 
 872 xfs_failaddr_t xfs_da3_blkinfo_verify(struct xfs_buf *bp,
 873                                       struct xfs_da3_blkinfo *hdr3);
 874 
 875 #endif /* __XFS_DA_FORMAT_H__ */

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