linux/fs/xfs/xfs_dir2_format.h
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   1/*
   2 * Copyright (c) 2000-2001,2005 Silicon Graphics, Inc.
   3 * Copyright (c) 2013 Red Hat, Inc.
   4 * All Rights Reserved.
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License as
   8 * published by the Free Software Foundation.
   9 *
  10 * This program is distributed in the hope that it would be useful,
  11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 * GNU General Public License for more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program; if not, write the Free Software Foundation,
  17 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  18 */
  19#ifndef __XFS_DIR2_FORMAT_H__
  20#define __XFS_DIR2_FORMAT_H__
  21
  22/*
  23 * Directory version 2.
  24 *
  25 * There are 4 possible formats:
  26 *  - shortform - embedded into the inode
  27 *  - single block - data with embedded leaf at the end
  28 *  - multiple data blocks, single leaf+freeindex block
  29 *  - data blocks, node and leaf blocks (btree), freeindex blocks
  30 *
  31 * Note: many node blocks structures and constants are shared with the attr
  32 * code and defined in xfs_da_btree.h.
  33 */
  34
  35#define XFS_DIR2_BLOCK_MAGIC    0x58443242      /* XD2B: single block dirs */
  36#define XFS_DIR2_DATA_MAGIC     0x58443244      /* XD2D: multiblock dirs */
  37#define XFS_DIR2_FREE_MAGIC     0x58443246      /* XD2F: free index blocks */
  38
  39/*
  40 * Directory Version 3 With CRCs.
  41 *
  42 * The tree formats are the same as for version 2 directories.  The difference
  43 * is in the block header and dirent formats. In many cases the v3 structures
  44 * use v2 definitions as they are no different and this makes code sharing much
  45 * easier.
  46 *
  47 * Also, the xfs_dir3_*() functions handle both v2 and v3 formats - if the
  48 * format is v2 then they switch to the existing v2 code, or the format is v3
  49 * they implement the v3 functionality. This means the existing dir2 is a mix of
  50 * xfs_dir2/xfs_dir3 calls and functions. The xfs_dir3 functions are called
  51 * where there is a difference in the formats, otherwise the code is unchanged.
  52 *
  53 * Where it is possible, the code decides what to do based on the magic numbers
  54 * in the blocks rather than feature bits in the superblock. This means the code
  55 * is as independent of the external XFS code as possible as doesn't require
  56 * passing struct xfs_mount pointers into places where it isn't really
  57 * necessary.
  58 *
  59 * Version 3 includes:
  60 *
  61 *      - a larger block header for CRC and identification purposes and so the
  62 *      offsets of all the structures inside the blocks are different.
  63 *
  64 *      - new magic numbers to be able to detect the v2/v3 types on the fly.
  65 */
  66
  67#define XFS_DIR3_BLOCK_MAGIC    0x58444233      /* XDB3: single block dirs */
  68#define XFS_DIR3_DATA_MAGIC     0x58444433      /* XDD3: multiblock dirs */
  69#define XFS_DIR3_FREE_MAGIC     0x58444633      /* XDF3: free index blocks */
  70
  71/*
  72 * Byte offset in data block and shortform entry.
  73 */
  74typedef __uint16_t      xfs_dir2_data_off_t;
  75#define NULLDATAOFF     0xffffU
  76typedef uint            xfs_dir2_data_aoff_t;   /* argument form */
  77
  78/*
  79 * Normalized offset (in a data block) of the entry, really xfs_dir2_data_off_t.
  80 * Only need 16 bits, this is the byte offset into the single block form.
  81 */
  82typedef struct { __uint8_t i[2]; } __arch_pack xfs_dir2_sf_off_t;
  83
  84/*
  85 * Offset in data space of a data entry.
  86 */
  87typedef __uint32_t      xfs_dir2_dataptr_t;
  88#define XFS_DIR2_MAX_DATAPTR    ((xfs_dir2_dataptr_t)0xffffffff)
  89#define XFS_DIR2_NULL_DATAPTR   ((xfs_dir2_dataptr_t)0)
  90
  91/*
  92 * Byte offset in a directory.
  93 */
  94typedef xfs_off_t       xfs_dir2_off_t;
  95
  96/*
  97 * Directory block number (logical dirblk in file)
  98 */
  99typedef __uint32_t      xfs_dir2_db_t;
 100
 101/*
 102 * Inode number stored as 8 8-bit values.
 103 */
 104typedef struct { __uint8_t i[8]; } xfs_dir2_ino8_t;
 105
 106/*
 107 * Inode number stored as 4 8-bit values.
 108 * Works a lot of the time, when all the inode numbers in a directory
 109 * fit in 32 bits.
 110 */
 111typedef struct { __uint8_t i[4]; } xfs_dir2_ino4_t;
 112
 113typedef union {
 114        xfs_dir2_ino8_t i8;
 115        xfs_dir2_ino4_t i4;
 116} xfs_dir2_inou_t;
 117#define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL)
 118
 119/*
 120 * Directory layout when stored internal to an inode.
 121 *
 122 * Small directories are packed as tightly as possible so as to fit into the
 123 * literal area of the inode.  These "shortform" directories consist of a
 124 * single xfs_dir2_sf_hdr header followed by zero or more xfs_dir2_sf_entry
 125 * structures.  Due the different inode number storage size and the variable
 126 * length name field in the xfs_dir2_sf_entry all these structure are
 127 * variable length, and the accessors in this file should be used to iterate
 128 * over them.
 129 */
 130typedef struct xfs_dir2_sf_hdr {
 131        __uint8_t               count;          /* count of entries */
 132        __uint8_t               i8count;        /* count of 8-byte inode #s */
 133        xfs_dir2_inou_t         parent;         /* parent dir inode number */
 134} __arch_pack xfs_dir2_sf_hdr_t;
 135
 136typedef struct xfs_dir2_sf_entry {
 137        __u8                    namelen;        /* actual name length */
 138        xfs_dir2_sf_off_t       offset;         /* saved offset */
 139        __u8                    name[];         /* name, variable size */
 140        /*
 141         * A xfs_dir2_ino8_t or xfs_dir2_ino4_t follows here, at a
 142         * variable offset after the name.
 143         */
 144} __arch_pack xfs_dir2_sf_entry_t;
 145
 146static inline int xfs_dir2_sf_hdr_size(int i8count)
 147{
 148        return sizeof(struct xfs_dir2_sf_hdr) -
 149                (i8count == 0) *
 150                (sizeof(xfs_dir2_ino8_t) - sizeof(xfs_dir2_ino4_t));
 151}
 152
 153static inline xfs_dir2_data_aoff_t
 154xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep)
 155{
 156        return get_unaligned_be16(&sfep->offset.i);
 157}
 158
 159static inline void
 160xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off)
 161{
 162        put_unaligned_be16(off, &sfep->offset.i);
 163}
 164
 165static inline int
 166xfs_dir2_sf_entsize(struct xfs_dir2_sf_hdr *hdr, int len)
 167{
 168        return sizeof(struct xfs_dir2_sf_entry) +       /* namelen + offset */
 169                len +                                   /* name */
 170                (hdr->i8count ?                         /* ino */
 171                 sizeof(xfs_dir2_ino8_t) :
 172                 sizeof(xfs_dir2_ino4_t));
 173}
 174
 175static inline struct xfs_dir2_sf_entry *
 176xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr)
 177{
 178        return (struct xfs_dir2_sf_entry *)
 179                ((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count));
 180}
 181
 182static inline struct xfs_dir2_sf_entry *
 183xfs_dir2_sf_nextentry(struct xfs_dir2_sf_hdr *hdr,
 184                struct xfs_dir2_sf_entry *sfep)
 185{
 186        return (struct xfs_dir2_sf_entry *)
 187                ((char *)sfep + xfs_dir2_sf_entsize(hdr, sfep->namelen));
 188}
 189
 190
 191/*
 192 * Data block structures.
 193 *
 194 * A pure data block looks like the following drawing on disk:
 195 *
 196 *    +-------------------------------------------------+
 197 *    | xfs_dir2_data_hdr_t                             |
 198 *    +-------------------------------------------------+
 199 *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 200 *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 201 *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 202 *    | ...                                             |
 203 *    +-------------------------------------------------+
 204 *    | unused space                                    |
 205 *    +-------------------------------------------------+
 206 *
 207 * As all the entries are variable size structures the accessors below should
 208 * be used to iterate over them.
 209 *
 210 * In addition to the pure data blocks for the data and node formats,
 211 * most structures are also used for the combined data/freespace "block"
 212 * format below.
 213 */
 214
 215#define XFS_DIR2_DATA_ALIGN_LOG 3               /* i.e., 8 bytes */
 216#define XFS_DIR2_DATA_ALIGN     (1 << XFS_DIR2_DATA_ALIGN_LOG)
 217#define XFS_DIR2_DATA_FREE_TAG  0xffff
 218#define XFS_DIR2_DATA_FD_COUNT  3
 219
 220/*
 221 * Directory address space divided into sections,
 222 * spaces separated by 32GB.
 223 */
 224#define XFS_DIR2_SPACE_SIZE     (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
 225#define XFS_DIR2_DATA_SPACE     0
 226#define XFS_DIR2_DATA_OFFSET    (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE)
 227#define XFS_DIR2_DATA_FIRSTDB(mp)       \
 228        xfs_dir2_byte_to_db(mp, XFS_DIR2_DATA_OFFSET)
 229
 230/*
 231 * Describe a free area in the data block.
 232 *
 233 * The freespace will be formatted as a xfs_dir2_data_unused_t.
 234 */
 235typedef struct xfs_dir2_data_free {
 236        __be16                  offset;         /* start of freespace */
 237        __be16                  length;         /* length of freespace */
 238} xfs_dir2_data_free_t;
 239
 240/*
 241 * Header for the data blocks.
 242 *
 243 * The code knows that XFS_DIR2_DATA_FD_COUNT is 3.
 244 */
 245typedef struct xfs_dir2_data_hdr {
 246        __be32                  magic;          /* XFS_DIR2_DATA_MAGIC or */
 247                                                /* XFS_DIR2_BLOCK_MAGIC */
 248        xfs_dir2_data_free_t    bestfree[XFS_DIR2_DATA_FD_COUNT];
 249} xfs_dir2_data_hdr_t;
 250
 251/*
 252 * define a structure for all the verification fields we are adding to the
 253 * directory block structures. This will be used in several structures.
 254 * The magic number must be the first entry to align with all the dir2
 255 * structures so we determine how to decode them just by the magic number.
 256 */
 257struct xfs_dir3_blk_hdr {
 258        __be32                  magic;  /* magic number */
 259        __be32                  crc;    /* CRC of block */
 260        __be64                  blkno;  /* first block of the buffer */
 261        __be64                  lsn;    /* sequence number of last write */
 262        uuid_t                  uuid;   /* filesystem we belong to */
 263        __be64                  owner;  /* inode that owns the block */
 264};
 265
 266struct xfs_dir3_data_hdr {
 267        struct xfs_dir3_blk_hdr hdr;
 268        xfs_dir2_data_free_t    best_free[XFS_DIR2_DATA_FD_COUNT];
 269        __be32                  pad;    /* 64 bit alignment */
 270};
 271
 272#define XFS_DIR3_DATA_CRC_OFF  offsetof(struct xfs_dir3_data_hdr, hdr.crc)
 273
 274static inline struct xfs_dir2_data_free *
 275xfs_dir3_data_bestfree_p(struct xfs_dir2_data_hdr *hdr)
 276{
 277        if (hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 278            hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
 279                struct xfs_dir3_data_hdr *hdr3 = (struct xfs_dir3_data_hdr *)hdr;
 280                return hdr3->best_free;
 281        }
 282        return hdr->bestfree;
 283}
 284
 285/*
 286 * Active entry in a data block.
 287 *
 288 * Aligned to 8 bytes.  After the variable length name field there is a
 289 * 2 byte tag field, which can be accessed using xfs_dir2_data_entry_tag_p.
 290 */
 291typedef struct xfs_dir2_data_entry {
 292        __be64                  inumber;        /* inode number */
 293        __u8                    namelen;        /* name length */
 294        __u8                    name[];         /* name bytes, no null */
 295     /* __be16                  tag; */         /* starting offset of us */
 296} xfs_dir2_data_entry_t;
 297
 298/*
 299 * Unused entry in a data block.
 300 *
 301 * Aligned to 8 bytes.  Tag appears as the last 2 bytes and must be accessed
 302 * using xfs_dir2_data_unused_tag_p.
 303 */
 304typedef struct xfs_dir2_data_unused {
 305        __be16                  freetag;        /* XFS_DIR2_DATA_FREE_TAG */
 306        __be16                  length;         /* total free length */
 307                                                /* variable offset */
 308        __be16                  tag;            /* starting offset of us */
 309} xfs_dir2_data_unused_t;
 310
 311/*
 312 * Size of a data entry.
 313 */
 314static inline int xfs_dir2_data_entsize(int n)
 315{
 316        return (int)roundup(offsetof(struct xfs_dir2_data_entry, name[0]) + n +
 317                 (uint)sizeof(xfs_dir2_data_off_t), XFS_DIR2_DATA_ALIGN);
 318}
 319
 320/*
 321 * Pointer to an entry's tag word.
 322 */
 323static inline __be16 *
 324xfs_dir2_data_entry_tag_p(struct xfs_dir2_data_entry *dep)
 325{
 326        return (__be16 *)((char *)dep +
 327                xfs_dir2_data_entsize(dep->namelen) - sizeof(__be16));
 328}
 329
 330/*
 331 * Pointer to a freespace's tag word.
 332 */
 333static inline __be16 *
 334xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup)
 335{
 336        return (__be16 *)((char *)dup +
 337                        be16_to_cpu(dup->length) - sizeof(__be16));
 338}
 339
 340static inline size_t
 341xfs_dir3_data_hdr_size(bool dir3)
 342{
 343        if (dir3)
 344                return sizeof(struct xfs_dir3_data_hdr);
 345        return sizeof(struct xfs_dir2_data_hdr);
 346}
 347
 348static inline size_t
 349xfs_dir3_data_entry_offset(struct xfs_dir2_data_hdr *hdr)
 350{
 351        bool dir3 = hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 352                    hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC);
 353        return xfs_dir3_data_hdr_size(dir3);
 354}
 355
 356static inline struct xfs_dir2_data_entry *
 357xfs_dir3_data_entry_p(struct xfs_dir2_data_hdr *hdr)
 358{
 359        return (struct xfs_dir2_data_entry *)
 360                ((char *)hdr + xfs_dir3_data_entry_offset(hdr));
 361}
 362
 363static inline struct xfs_dir2_data_unused *
 364xfs_dir3_data_unused_p(struct xfs_dir2_data_hdr *hdr)
 365{
 366        return (struct xfs_dir2_data_unused *)
 367                ((char *)hdr + xfs_dir3_data_entry_offset(hdr));
 368}
 369
 370/*
 371 * Offsets of . and .. in data space (always block 0)
 372 *
 373 * The macros are used for shortform directories as they have no headers to read
 374 * the magic number out of. Shortform directories need to know the size of the
 375 * data block header because the sfe embeds the block offset of the entry into
 376 * it so that it doesn't change when format conversion occurs. Bad Things Happen
 377 * if we don't follow this rule.
 378 */
 379#define XFS_DIR3_DATA_DOT_OFFSET(mp)    \
 380        xfs_dir3_data_hdr_size(xfs_sb_version_hascrc(&(mp)->m_sb))
 381#define XFS_DIR3_DATA_DOTDOT_OFFSET(mp) \
 382        (XFS_DIR3_DATA_DOT_OFFSET(mp) + xfs_dir2_data_entsize(1))
 383#define XFS_DIR3_DATA_FIRST_OFFSET(mp)          \
 384        (XFS_DIR3_DATA_DOTDOT_OFFSET(mp) + xfs_dir2_data_entsize(2))
 385
 386static inline xfs_dir2_data_aoff_t
 387xfs_dir3_data_dot_offset(struct xfs_dir2_data_hdr *hdr)
 388{
 389        return xfs_dir3_data_entry_offset(hdr);
 390}
 391
 392static inline xfs_dir2_data_aoff_t
 393xfs_dir3_data_dotdot_offset(struct xfs_dir2_data_hdr *hdr)
 394{
 395        return xfs_dir3_data_dot_offset(hdr) + xfs_dir2_data_entsize(1);
 396}
 397
 398static inline xfs_dir2_data_aoff_t
 399xfs_dir3_data_first_offset(struct xfs_dir2_data_hdr *hdr)
 400{
 401        return xfs_dir3_data_dotdot_offset(hdr) + xfs_dir2_data_entsize(2);
 402}
 403
 404/*
 405 * location of . and .. in data space (always block 0)
 406 */
 407static inline struct xfs_dir2_data_entry *
 408xfs_dir3_data_dot_entry_p(struct xfs_dir2_data_hdr *hdr)
 409{
 410        return (struct xfs_dir2_data_entry *)
 411                ((char *)hdr + xfs_dir3_data_dot_offset(hdr));
 412}
 413
 414static inline struct xfs_dir2_data_entry *
 415xfs_dir3_data_dotdot_entry_p(struct xfs_dir2_data_hdr *hdr)
 416{
 417        return (struct xfs_dir2_data_entry *)
 418                ((char *)hdr + xfs_dir3_data_dotdot_offset(hdr));
 419}
 420
 421static inline struct xfs_dir2_data_entry *
 422xfs_dir3_data_first_entry_p(struct xfs_dir2_data_hdr *hdr)
 423{
 424        return (struct xfs_dir2_data_entry *)
 425                ((char *)hdr + xfs_dir3_data_first_offset(hdr));
 426}
 427
 428/*
 429 * Leaf block structures.
 430 *
 431 * A pure leaf block looks like the following drawing on disk:
 432 *
 433 *    +---------------------------+
 434 *    | xfs_dir2_leaf_hdr_t       |
 435 *    +---------------------------+
 436 *    | xfs_dir2_leaf_entry_t     |
 437 *    | xfs_dir2_leaf_entry_t     |
 438 *    | xfs_dir2_leaf_entry_t     |
 439 *    | xfs_dir2_leaf_entry_t     |
 440 *    | ...                       |
 441 *    +---------------------------+
 442 *    | xfs_dir2_data_off_t       |
 443 *    | xfs_dir2_data_off_t       |
 444 *    | xfs_dir2_data_off_t       |
 445 *    | ...                       |
 446 *    +---------------------------+
 447 *    | xfs_dir2_leaf_tail_t      |
 448 *    +---------------------------+
 449 *
 450 * The xfs_dir2_data_off_t members (bests) and tail are at the end of the block
 451 * for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present
 452 * for directories with separate leaf nodes and free space blocks
 453 * (magic = XFS_DIR2_LEAFN_MAGIC).
 454 *
 455 * As all the entries are variable size structures the accessors below should
 456 * be used to iterate over them.
 457 */
 458
 459/*
 460 * Offset of the leaf/node space.  First block in this space
 461 * is the btree root.
 462 */
 463#define XFS_DIR2_LEAF_SPACE     1
 464#define XFS_DIR2_LEAF_OFFSET    (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE)
 465#define XFS_DIR2_LEAF_FIRSTDB(mp)       \
 466        xfs_dir2_byte_to_db(mp, XFS_DIR2_LEAF_OFFSET)
 467
 468/*
 469 * Leaf block header.
 470 */
 471typedef struct xfs_dir2_leaf_hdr {
 472        xfs_da_blkinfo_t        info;           /* header for da routines */
 473        __be16                  count;          /* count of entries */
 474        __be16                  stale;          /* count of stale entries */
 475} xfs_dir2_leaf_hdr_t;
 476
 477struct xfs_dir3_leaf_hdr {
 478        struct xfs_da3_blkinfo  info;           /* header for da routines */
 479        __be16                  count;          /* count of entries */
 480        __be16                  stale;          /* count of stale entries */
 481        __be32                  pad;            /* 64 bit alignment */
 482};
 483
 484struct xfs_dir3_icleaf_hdr {
 485        __uint32_t              forw;
 486        __uint32_t              back;
 487        __uint16_t              magic;
 488        __uint16_t              count;
 489        __uint16_t              stale;
 490};
 491
 492/*
 493 * Leaf block entry.
 494 */
 495typedef struct xfs_dir2_leaf_entry {
 496        __be32                  hashval;        /* hash value of name */
 497        __be32                  address;        /* address of data entry */
 498} xfs_dir2_leaf_entry_t;
 499
 500/*
 501 * Leaf block tail.
 502 */
 503typedef struct xfs_dir2_leaf_tail {
 504        __be32                  bestcount;
 505} xfs_dir2_leaf_tail_t;
 506
 507/*
 508 * Leaf block.
 509 */
 510typedef struct xfs_dir2_leaf {
 511        xfs_dir2_leaf_hdr_t     hdr;                    /* leaf header */
 512        xfs_dir2_leaf_entry_t   __ents[];               /* entries */
 513} xfs_dir2_leaf_t;
 514
 515struct xfs_dir3_leaf {
 516        struct xfs_dir3_leaf_hdr        hdr;            /* leaf header */
 517        struct xfs_dir2_leaf_entry      __ents[];       /* entries */
 518};
 519
 520#define XFS_DIR3_LEAF_CRC_OFF  offsetof(struct xfs_dir3_leaf_hdr, info.crc)
 521
 522static inline int
 523xfs_dir3_leaf_hdr_size(struct xfs_dir2_leaf *lp)
 524{
 525        if (lp->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAF1_MAGIC) ||
 526            lp->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC))
 527                return sizeof(struct xfs_dir3_leaf_hdr);
 528        return sizeof(struct xfs_dir2_leaf_hdr);
 529}
 530
 531static inline int
 532xfs_dir3_max_leaf_ents(struct xfs_mount *mp, struct xfs_dir2_leaf *lp)
 533{
 534        return (mp->m_dirblksize - xfs_dir3_leaf_hdr_size(lp)) /
 535                (uint)sizeof(struct xfs_dir2_leaf_entry);
 536}
 537
 538/*
 539 * Get address of the bestcount field in the single-leaf block.
 540 */
 541static inline struct xfs_dir2_leaf_entry *
 542xfs_dir3_leaf_ents_p(struct xfs_dir2_leaf *lp)
 543{
 544        if (lp->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAF1_MAGIC) ||
 545            lp->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC)) {
 546                struct xfs_dir3_leaf *lp3 = (struct xfs_dir3_leaf *)lp;
 547                return lp3->__ents;
 548        }
 549        return lp->__ents;
 550}
 551
 552/*
 553 * Get address of the bestcount field in the single-leaf block.
 554 */
 555static inline struct xfs_dir2_leaf_tail *
 556xfs_dir2_leaf_tail_p(struct xfs_mount *mp, struct xfs_dir2_leaf *lp)
 557{
 558        return (struct xfs_dir2_leaf_tail *)
 559                ((char *)lp + mp->m_dirblksize -
 560                  sizeof(struct xfs_dir2_leaf_tail));
 561}
 562
 563/*
 564 * Get address of the bests array in the single-leaf block.
 565 */
 566static inline __be16 *
 567xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp)
 568{
 569        return (__be16 *)ltp - be32_to_cpu(ltp->bestcount);
 570}
 571
 572/*
 573 * DB blocks here are logical directory block numbers, not filesystem blocks.
 574 */
 575
 576/*
 577 * Convert dataptr to byte in file space
 578 */
 579static inline xfs_dir2_off_t
 580xfs_dir2_dataptr_to_byte(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
 581{
 582        return (xfs_dir2_off_t)dp << XFS_DIR2_DATA_ALIGN_LOG;
 583}
 584
 585/*
 586 * Convert byte in file space to dataptr.  It had better be aligned.
 587 */
 588static inline xfs_dir2_dataptr_t
 589xfs_dir2_byte_to_dataptr(struct xfs_mount *mp, xfs_dir2_off_t by)
 590{
 591        return (xfs_dir2_dataptr_t)(by >> XFS_DIR2_DATA_ALIGN_LOG);
 592}
 593
 594/*
 595 * Convert byte in space to (DB) block
 596 */
 597static inline xfs_dir2_db_t
 598xfs_dir2_byte_to_db(struct xfs_mount *mp, xfs_dir2_off_t by)
 599{
 600        return (xfs_dir2_db_t)
 601                (by >> (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog));
 602}
 603
 604/*
 605 * Convert dataptr to a block number
 606 */
 607static inline xfs_dir2_db_t
 608xfs_dir2_dataptr_to_db(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
 609{
 610        return xfs_dir2_byte_to_db(mp, xfs_dir2_dataptr_to_byte(mp, dp));
 611}
 612
 613/*
 614 * Convert byte in space to offset in a block
 615 */
 616static inline xfs_dir2_data_aoff_t
 617xfs_dir2_byte_to_off(struct xfs_mount *mp, xfs_dir2_off_t by)
 618{
 619        return (xfs_dir2_data_aoff_t)(by &
 620                ((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) - 1));
 621}
 622
 623/*
 624 * Convert dataptr to a byte offset in a block
 625 */
 626static inline xfs_dir2_data_aoff_t
 627xfs_dir2_dataptr_to_off(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
 628{
 629        return xfs_dir2_byte_to_off(mp, xfs_dir2_dataptr_to_byte(mp, dp));
 630}
 631
 632/*
 633 * Convert block and offset to byte in space
 634 */
 635static inline xfs_dir2_off_t
 636xfs_dir2_db_off_to_byte(struct xfs_mount *mp, xfs_dir2_db_t db,
 637                        xfs_dir2_data_aoff_t o)
 638{
 639        return ((xfs_dir2_off_t)db <<
 640                (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) + o;
 641}
 642
 643/*
 644 * Convert block (DB) to block (dablk)
 645 */
 646static inline xfs_dablk_t
 647xfs_dir2_db_to_da(struct xfs_mount *mp, xfs_dir2_db_t db)
 648{
 649        return (xfs_dablk_t)(db << mp->m_sb.sb_dirblklog);
 650}
 651
 652/*
 653 * Convert byte in space to (DA) block
 654 */
 655static inline xfs_dablk_t
 656xfs_dir2_byte_to_da(struct xfs_mount *mp, xfs_dir2_off_t by)
 657{
 658        return xfs_dir2_db_to_da(mp, xfs_dir2_byte_to_db(mp, by));
 659}
 660
 661/*
 662 * Convert block and offset to dataptr
 663 */
 664static inline xfs_dir2_dataptr_t
 665xfs_dir2_db_off_to_dataptr(struct xfs_mount *mp, xfs_dir2_db_t db,
 666                           xfs_dir2_data_aoff_t o)
 667{
 668        return xfs_dir2_byte_to_dataptr(mp, xfs_dir2_db_off_to_byte(mp, db, o));
 669}
 670
 671/*
 672 * Convert block (dablk) to block (DB)
 673 */
 674static inline xfs_dir2_db_t
 675xfs_dir2_da_to_db(struct xfs_mount *mp, xfs_dablk_t da)
 676{
 677        return (xfs_dir2_db_t)(da >> mp->m_sb.sb_dirblklog);
 678}
 679
 680/*
 681 * Convert block (dablk) to byte offset in space
 682 */
 683static inline xfs_dir2_off_t
 684xfs_dir2_da_to_byte(struct xfs_mount *mp, xfs_dablk_t da)
 685{
 686        return xfs_dir2_db_off_to_byte(mp, xfs_dir2_da_to_db(mp, da), 0);
 687}
 688
 689/*
 690 * Free space block defintions for the node format.
 691 */
 692
 693/*
 694 * Offset of the freespace index.
 695 */
 696#define XFS_DIR2_FREE_SPACE     2
 697#define XFS_DIR2_FREE_OFFSET    (XFS_DIR2_FREE_SPACE * XFS_DIR2_SPACE_SIZE)
 698#define XFS_DIR2_FREE_FIRSTDB(mp)       \
 699        xfs_dir2_byte_to_db(mp, XFS_DIR2_FREE_OFFSET)
 700
 701typedef struct xfs_dir2_free_hdr {
 702        __be32                  magic;          /* XFS_DIR2_FREE_MAGIC */
 703        __be32                  firstdb;        /* db of first entry */
 704        __be32                  nvalid;         /* count of valid entries */
 705        __be32                  nused;          /* count of used entries */
 706} xfs_dir2_free_hdr_t;
 707
 708typedef struct xfs_dir2_free {
 709        xfs_dir2_free_hdr_t     hdr;            /* block header */
 710        __be16                  bests[];        /* best free counts */
 711                                                /* unused entries are -1 */
 712} xfs_dir2_free_t;
 713
 714struct xfs_dir3_free_hdr {
 715        struct xfs_dir3_blk_hdr hdr;
 716        __be32                  firstdb;        /* db of first entry */
 717        __be32                  nvalid;         /* count of valid entries */
 718        __be32                  nused;          /* count of used entries */
 719        __be32                  pad;            /* 64 bit alignment */
 720};
 721
 722struct xfs_dir3_free {
 723        struct xfs_dir3_free_hdr hdr;
 724        __be16                  bests[];        /* best free counts */
 725                                                /* unused entries are -1 */
 726};
 727
 728#define XFS_DIR3_FREE_CRC_OFF  offsetof(struct xfs_dir3_free, hdr.hdr.crc)
 729
 730/*
 731 * In core version of the free block header, abstracted away from on-disk format
 732 * differences. Use this in the code, and convert to/from the disk version using
 733 * xfs_dir3_free_hdr_from_disk/xfs_dir3_free_hdr_to_disk.
 734 */
 735struct xfs_dir3_icfree_hdr {
 736        __uint32_t      magic;
 737        __uint32_t      firstdb;
 738        __uint32_t      nvalid;
 739        __uint32_t      nused;
 740
 741};
 742
 743void xfs_dir3_free_hdr_from_disk(struct xfs_dir3_icfree_hdr *to,
 744                                 struct xfs_dir2_free *from);
 745
 746static inline int
 747xfs_dir3_free_hdr_size(struct xfs_mount *mp)
 748{
 749        if (xfs_sb_version_hascrc(&mp->m_sb))
 750                return sizeof(struct xfs_dir3_free_hdr);
 751        return sizeof(struct xfs_dir2_free_hdr);
 752}
 753
 754static inline int
 755xfs_dir3_free_max_bests(struct xfs_mount *mp)
 756{
 757        return (mp->m_dirblksize - xfs_dir3_free_hdr_size(mp)) /
 758                sizeof(xfs_dir2_data_off_t);
 759}
 760
 761static inline __be16 *
 762xfs_dir3_free_bests_p(struct xfs_mount *mp, struct xfs_dir2_free *free)
 763{
 764        return (__be16 *)((char *)free + xfs_dir3_free_hdr_size(mp));
 765}
 766
 767/*
 768 * Convert data space db to the corresponding free db.
 769 */
 770static inline xfs_dir2_db_t
 771xfs_dir2_db_to_fdb(struct xfs_mount *mp, xfs_dir2_db_t db)
 772{
 773        return XFS_DIR2_FREE_FIRSTDB(mp) + db / xfs_dir3_free_max_bests(mp);
 774}
 775
 776/*
 777 * Convert data space db to the corresponding index in a free db.
 778 */
 779static inline int
 780xfs_dir2_db_to_fdindex(struct xfs_mount *mp, xfs_dir2_db_t db)
 781{
 782        return db % xfs_dir3_free_max_bests(mp);
 783}
 784
 785/*
 786 * Single block format.
 787 *
 788 * The single block format looks like the following drawing on disk:
 789 *
 790 *    +-------------------------------------------------+
 791 *    | xfs_dir2_data_hdr_t                             |
 792 *    +-------------------------------------------------+
 793 *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 794 *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 795 *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t :
 796 *    | ...                                             |
 797 *    +-------------------------------------------------+
 798 *    | unused space                                    |
 799 *    +-------------------------------------------------+
 800 *    | ...                                             |
 801 *    | xfs_dir2_leaf_entry_t                           |
 802 *    | xfs_dir2_leaf_entry_t                           |
 803 *    +-------------------------------------------------+
 804 *    | xfs_dir2_block_tail_t                           |
 805 *    +-------------------------------------------------+
 806 *
 807 * As all the entries are variable size structures the accessors below should
 808 * be used to iterate over them.
 809 */
 810
 811typedef struct xfs_dir2_block_tail {
 812        __be32          count;                  /* count of leaf entries */
 813        __be32          stale;                  /* count of stale lf entries */
 814} xfs_dir2_block_tail_t;
 815
 816/*
 817 * Pointer to the leaf header embedded in a data block (1-block format)
 818 */
 819static inline struct xfs_dir2_block_tail *
 820xfs_dir2_block_tail_p(struct xfs_mount *mp, struct xfs_dir2_data_hdr *hdr)
 821{
 822        return ((struct xfs_dir2_block_tail *)
 823                ((char *)hdr + mp->m_dirblksize)) - 1;
 824}
 825
 826/*
 827 * Pointer to the leaf entries embedded in a data block (1-block format)
 828 */
 829static inline struct xfs_dir2_leaf_entry *
 830xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp)
 831{
 832        return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count);
 833}
 834
 835#endif /* __XFS_DIR2_FORMAT_H__ */
 836
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