fs/xfs/xfs_dir2_format.h

   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  */
  74 typedef __uint16_t      xfs_dir2_data_off_t;
  75 #define NULLDATAOFF     0xffffU
  76 typedef 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  */
  82 typedef struct { __uint8_t i[2]; } __arch_pack xfs_dir2_sf_off_t;
  83
  84 /*
  85  * Offset in data space of a data entry.
  86  */
  87 typedef __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  */
  94 typedef xfs_off_t       xfs_dir2_off_t;
  95
  96 /*
  97  * Directory block number (logical dirblk in file)
  98  */
  99 typedef __uint32_t      xfs_dir2_db_t;
 100
 101 /*
 102  * Inode number stored as 8 8-bit values.
 103  */
 104 typedef 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  */
 111 typedef struct { __uint8_t i[4]; } xfs_dir2_ino4_t;
 112
 113 typedef 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  */
 130 typedef 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
 136 typedef 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
 146 static 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
 153 static inline xfs_dir2_data_aoff_t
 154 xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep)
 155 {
 156         return get_unaligned_be16(&sfep->offset.i);
 157 }
 158
 159 static inline void
 160 xfs_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
 165 static inline int
 166 xfs_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
 175 static inline struct xfs_dir2_sf_entry *
 176 xfs_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
 182 static inline struct xfs_dir2_sf_entry *
 183 xfs_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  */
 235 typedef 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  */
 245 typedef 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  */
 257 struct 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
 266 struct 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 };
 270
 271 #define XFS_DIR3_DATA_CRC_OFF  offsetof(struct xfs_dir3_data_hdr, hdr.crc)
 272
 273 static inline struct xfs_dir2_data_free *
 274 xfs_dir3_data_bestfree_p(struct xfs_dir2_data_hdr *hdr)
 275 {
 276         if (hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 277             hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
 278                 struct xfs_dir3_data_hdr *hdr3 = (struct xfs_dir3_data_hdr *)hdr;
 279                 return hdr3->best_free;
 280         }
 281         return hdr->bestfree;
 282 }
 283
 284 /*
 285  * Active entry in a data block.
 286  *
 287  * Aligned to 8 bytes.  After the variable length name field there is a
 288  * 2 byte tag field, which can be accessed using xfs_dir2_data_entry_tag_p.
 289  */
 290 typedef struct xfs_dir2_data_entry {
 291         __be64                  inumber;        /* inode number */
 292         __u8                    namelen;        /* name length */
 293         __u8                    name[];         /* name bytes, no null */
 294      /* __be16                  tag; */         /* starting offset of us */
 295 } xfs_dir2_data_entry_t;
 296
 297 /*
 298  * Unused entry in a data block.
 299  *
 300  * Aligned to 8 bytes.  Tag appears as the last 2 bytes and must be accessed
 301  * using xfs_dir2_data_unused_tag_p.
 302  */
 303 typedef struct xfs_dir2_data_unused {
 304         __be16                  freetag;        /* XFS_DIR2_DATA_FREE_TAG */
 305         __be16                  length;         /* total free length */
 306                                                 /* variable offset */
 307         __be16                  tag;            /* starting offset of us */
 308 } xfs_dir2_data_unused_t;
 309
 310 /*
 311  * Size of a data entry.
 312  */
 313 static inline int xfs_dir2_data_entsize(int n)
 314 {
 315         return (int)roundup(offsetof(struct xfs_dir2_data_entry, name[0]) + n +
 316                  (uint)sizeof(xfs_dir2_data_off_t), XFS_DIR2_DATA_ALIGN);
 317 }
 318
 319 /*
 320  * Pointer to an entry's tag word.
 321  */
 322 static inline __be16 *
 323 xfs_dir2_data_entry_tag_p(struct xfs_dir2_data_entry *dep)
 324 {
 325         return (__be16 *)((char *)dep +
 326                 xfs_dir2_data_entsize(dep->namelen) - sizeof(__be16));
 327 }
 328
 329 /*
 330  * Pointer to a freespace's tag word.
 331  */
 332 static inline __be16 *
 333 xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup)
 334 {
 335         return (__be16 *)((char *)dup +
 336                         be16_to_cpu(dup->length) - sizeof(__be16));
 337 }
 338
 339 static inline size_t
 340 xfs_dir3_data_hdr_size(bool dir3)
 341 {
 342         if (dir3)
 343                 return sizeof(struct xfs_dir3_data_hdr);
 344         return sizeof(struct xfs_dir2_data_hdr);
 345 }
 346
 347 static inline size_t
 348 xfs_dir3_data_entry_offset(struct xfs_dir2_data_hdr *hdr)
 349 {
 350         bool dir3 = hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 351                     hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC);
 352         return xfs_dir3_data_hdr_size(dir3);
 353 }
 354
 355 static inline struct xfs_dir2_data_entry *
 356 xfs_dir3_data_entry_p(struct xfs_dir2_data_hdr *hdr)
 357 {
 358         return (struct xfs_dir2_data_entry *)
 359                 ((char *)hdr + xfs_dir3_data_entry_offset(hdr));
 360 }
 361
 362 static inline struct xfs_dir2_data_unused *
 363 xfs_dir3_data_unused_p(struct xfs_dir2_data_hdr *hdr)
 364 {
 365         return (struct xfs_dir2_data_unused *)
 366                 ((char *)hdr + xfs_dir3_data_entry_offset(hdr));
 367 }
 368
 369 /*
 370  * Offsets of . and .. in data space (always block 0)
 371  *
 372  * The macros are used for shortform directories as they have no headers to read
 373  * the magic number out of. Shortform directories need to know the size of the
 374  * data block header because the sfe embeds the block offset of the entry into
 375  * it so that it doesn't change when format conversion occurs. Bad Things Happen
 376  * if we don't follow this rule.
 377  */
 378 #define XFS_DIR3_DATA_DOT_OFFSET(mp)    \
 379         xfs_dir3_data_hdr_size(xfs_sb_version_hascrc(&(mp)->m_sb))
 380 #define XFS_DIR3_DATA_DOTDOT_OFFSET(mp) \
 381         (XFS_DIR3_DATA_DOT_OFFSET(mp) + xfs_dir2_data_entsize(1))
 382 #define XFS_DIR3_DATA_FIRST_OFFSET(mp)          \
 383         (XFS_DIR3_DATA_DOTDOT_OFFSET(mp) + xfs_dir2_data_entsize(2))
 384
 385 static inline xfs_dir2_data_aoff_t
 386 xfs_dir3_data_dot_offset(struct xfs_dir2_data_hdr *hdr)
 387 {
 388         return xfs_dir3_data_entry_offset(hdr);
 389 }
 390
 391 static inline xfs_dir2_data_aoff_t
 392 xfs_dir3_data_dotdot_offset(struct xfs_dir2_data_hdr *hdr)
 393 {
 394         return xfs_dir3_data_dot_offset(hdr) + xfs_dir2_data_entsize(1);
 395 }
 396
 397 static inline xfs_dir2_data_aoff_t
 398 xfs_dir3_data_first_offset(struct xfs_dir2_data_hdr *hdr)
 399 {
 400         return xfs_dir3_data_dotdot_offset(hdr) + xfs_dir2_data_entsize(2);
 401 }
 402
 403 /*
 404  * location of . and .. in data space (always block 0)
 405  */
 406 static inline struct xfs_dir2_data_entry *
 407 xfs_dir3_data_dot_entry_p(struct xfs_dir2_data_hdr *hdr)
 408 {
 409         return (struct xfs_dir2_data_entry *)
 410                 ((char *)hdr + xfs_dir3_data_dot_offset(hdr));
 411 }
 412
 413 static inline struct xfs_dir2_data_entry *
 414 xfs_dir3_data_dotdot_entry_p(struct xfs_dir2_data_hdr *hdr)
 415 {
 416         return (struct xfs_dir2_data_entry *)
 417                 ((char *)hdr + xfs_dir3_data_dotdot_offset(hdr));
 418 }
 419
 420 static inline struct xfs_dir2_data_entry *
 421 xfs_dir3_data_first_entry_p(struct xfs_dir2_data_hdr *hdr)
 422 {
 423         return (struct xfs_dir2_data_entry *)
 424                 ((char *)hdr + xfs_dir3_data_first_offset(hdr));
 425 }
 426
 427 /*
 428  * Leaf block structures.
 429  *
 430  * A pure leaf block looks like the following drawing on disk:
 431  *
 432  *    +---------------------------+
 433  *    | xfs_dir2_leaf_hdr_t       |
 434  *    +---------------------------+
 435  *    | xfs_dir2_leaf_entry_t     |
 436  *    | xfs_dir2_leaf_entry_t     |
 437  *    | xfs_dir2_leaf_entry_t     |
 438  *    | xfs_dir2_leaf_entry_t     |
 439  *    | ...                       |
 440  *    +---------------------------+
 441  *    | xfs_dir2_data_off_t       |
 442  *    | xfs_dir2_data_off_t       |
 443  *    | xfs_dir2_data_off_t       |
 444  *    | ...                       |
 445  *    +---------------------------+
 446  *    | xfs_dir2_leaf_tail_t      |
 447  *    +---------------------------+
 448  *
 449  * The xfs_dir2_data_off_t members (bests) and tail are at the end of the block
 450  * for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present
 451  * for directories with separate leaf nodes and free space blocks
 452  * (magic = XFS_DIR2_LEAFN_MAGIC).
 453  *
 454  * As all the entries are variable size structures the accessors below should
 455  * be used to iterate over them.
 456  */
 457
 458 /*
 459  * Offset of the leaf/node space.  First block in this space
 460  * is the btree root.
 461  */
 462 #define XFS_DIR2_LEAF_SPACE     1
 463 #define XFS_DIR2_LEAF_OFFSET    (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE)
 464 #define XFS_DIR2_LEAF_FIRSTDB(mp)       \
 465         xfs_dir2_byte_to_db(mp, XFS_DIR2_LEAF_OFFSET)
 466
 467 /*
 468  * Leaf block header.
 469  */
 470 typedef struct xfs_dir2_leaf_hdr {
 471         xfs_da_blkinfo_t        info;           /* header for da routines */
 472         __be16                  count;          /* count of entries */
 473         __be16                  stale;          /* count of stale entries */
 474 } xfs_dir2_leaf_hdr_t;
 475
 476 struct xfs_dir3_leaf_hdr {
 477         struct xfs_da3_blkinfo  info;           /* header for da routines */
 478         __be16                  count;          /* count of entries */
 479         __be16                  stale;          /* count of stale entries */
 480         __be32                  pad;
 481 };
 482
 483 struct xfs_dir3_icleaf_hdr {
 484         __uint32_t              forw;
 485         __uint32_t              back;
 486         __uint16_t              magic;
 487         __uint16_t              count;
 488         __uint16_t              stale;
 489 };
 490
 491 /*
 492  * Leaf block entry.
 493  */
 494 typedef struct xfs_dir2_leaf_entry {
 495         __be32                  hashval;        /* hash value of name */
 496         __be32                  address;        /* address of data entry */
 497 } xfs_dir2_leaf_entry_t;
 498
 499 /*
 500  * Leaf block tail.
 501  */
 502 typedef struct xfs_dir2_leaf_tail {
 503         __be32                  bestcount;
 504 } xfs_dir2_leaf_tail_t;
 505
 506 /*
 507  * Leaf block.
 508  */
 509 typedef struct xfs_dir2_leaf {
 510         xfs_dir2_leaf_hdr_t     hdr;                    /* leaf header */
 511         xfs_dir2_leaf_entry_t   __ents[];               /* entries */
 512 } xfs_dir2_leaf_t;
 513
 514 struct xfs_dir3_leaf {
 515         struct xfs_dir3_leaf_hdr        hdr;            /* leaf header */
 516         struct xfs_dir2_leaf_entry      __ents[];       /* entries */
 517 };
 518
 519 #define XFS_DIR3_LEAF_CRC_OFF  offsetof(struct xfs_dir3_leaf_hdr, info.crc)
 520
 521 static inline int
 522 xfs_dir3_leaf_hdr_size(struct xfs_dir2_leaf *lp)
 523 {
 524         if (lp->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAF1_MAGIC) ||
 525             lp->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC))
 526                 return sizeof(struct xfs_dir3_leaf_hdr);
 527         return sizeof(struct xfs_dir2_leaf_hdr);
 528 }
 529
 530 static inline int
 531 xfs_dir3_max_leaf_ents(struct xfs_mount *mp, struct xfs_dir2_leaf *lp)
 532 {
 533         return (mp->m_dirblksize - xfs_dir3_leaf_hdr_size(lp)) /
 534                 (uint)sizeof(struct xfs_dir2_leaf_entry);
 535 }
 536
 537 /*
 538  * Get address of the bestcount field in the single-leaf block.
 539  */
 540 static inline struct xfs_dir2_leaf_entry *
 541 xfs_dir3_leaf_ents_p(struct xfs_dir2_leaf *lp)
 542 {
 543         if (lp->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAF1_MAGIC) ||
 544             lp->hdr.info.magic == cpu_to_be16(XFS_DIR3_LEAFN_MAGIC)) {
 545                 struct xfs_dir3_leaf *lp3 = (struct xfs_dir3_leaf *)lp;
 546                 return lp3->__ents;
 547         }
 548         return lp->__ents;
 549 }
 550
 551 /*
 552  * Get address of the bestcount field in the single-leaf block.
 553  */
 554 static inline struct xfs_dir2_leaf_tail *
 555 xfs_dir2_leaf_tail_p(struct xfs_mount *mp, struct xfs_dir2_leaf *lp)
 556 {
 557         return (struct xfs_dir2_leaf_tail *)
 558                 ((char *)lp + mp->m_dirblksize -
 559                   sizeof(struct xfs_dir2_leaf_tail));
 560 }
 561
 562 /*
 563  * Get address of the bests array in the single-leaf block.
 564  */
 565 static inline __be16 *
 566 xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp)
 567 {
 568         return (__be16 *)ltp - be32_to_cpu(ltp->bestcount);
 569 }
 570
 571 /*
 572  * DB blocks here are logical directory block numbers, not filesystem blocks.
 573  */
 574
 575 /*
 576  * Convert dataptr to byte in file space
 577  */
 578 static inline xfs_dir2_off_t
 579 xfs_dir2_dataptr_to_byte(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
 580 {
 581         return (xfs_dir2_off_t)dp << XFS_DIR2_DATA_ALIGN_LOG;
 582 }
 583
 584 /*
 585  * Convert byte in file space to dataptr.  It had better be aligned.
 586  */
 587 static inline xfs_dir2_dataptr_t
 588 xfs_dir2_byte_to_dataptr(struct xfs_mount *mp, xfs_dir2_off_t by)
 589 {
 590         return (xfs_dir2_dataptr_t)(by >> XFS_DIR2_DATA_ALIGN_LOG);
 591 }
 592
 593 /*
 594  * Convert byte in space to (DB) block
 595  */
 596 static inline xfs_dir2_db_t
 597 xfs_dir2_byte_to_db(struct xfs_mount *mp, xfs_dir2_off_t by)
 598 {
 599         return (xfs_dir2_db_t)
 600                 (by >> (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog));
 601 }
 602
 603 /*
 604  * Convert dataptr to a block number
 605  */
 606 static inline xfs_dir2_db_t
 607 xfs_dir2_dataptr_to_db(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
 608 {
 609         return xfs_dir2_byte_to_db(mp, xfs_dir2_dataptr_to_byte(mp, dp));
 610 }
 611
 612 /*
 613  * Convert byte in space to offset in a block
 614  */
 615 static inline xfs_dir2_data_aoff_t
 616 xfs_dir2_byte_to_off(struct xfs_mount *mp, xfs_dir2_off_t by)
 617 {
 618         return (xfs_dir2_data_aoff_t)(by &
 619                 ((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) - 1));
 620 }
 621
 622 /*
 623  * Convert dataptr to a byte offset in a block
 624  */
 625 static inline xfs_dir2_data_aoff_t
 626 xfs_dir2_dataptr_to_off(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
 627 {
 628         return xfs_dir2_byte_to_off(mp, xfs_dir2_dataptr_to_byte(mp, dp));
 629 }
 630
 631 /*
 632  * Convert block and offset to byte in space
 633  */
 634 static inline xfs_dir2_off_t
 635 xfs_dir2_db_off_to_byte(struct xfs_mount *mp, xfs_dir2_db_t db,
 636                         xfs_dir2_data_aoff_t o)
 637 {
 638         return ((xfs_dir2_off_t)db <<
 639                 (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) + o;
 640 }
 641
 642 /*
 643  * Convert block (DB) to block (dablk)
 644  */
 645 static inline xfs_dablk_t
 646 xfs_dir2_db_to_da(struct xfs_mount *mp, xfs_dir2_db_t db)
 647 {
 648         return (xfs_dablk_t)(db << mp->m_sb.sb_dirblklog);
 649 }
 650
 651 /*
 652  * Convert byte in space to (DA) block
 653  */
 654 static inline xfs_dablk_t
 655 xfs_dir2_byte_to_da(struct xfs_mount *mp, xfs_dir2_off_t by)
 656 {
 657         return xfs_dir2_db_to_da(mp, xfs_dir2_byte_to_db(mp, by));
 658 }
 659
 660 /*
 661  * Convert block and offset to dataptr
 662  */
 663 static inline xfs_dir2_dataptr_t
 664 xfs_dir2_db_off_to_dataptr(struct xfs_mount *mp, xfs_dir2_db_t db,
 665                            xfs_dir2_data_aoff_t o)
 666 {
 667         return xfs_dir2_byte_to_dataptr(mp, xfs_dir2_db_off_to_byte(mp, db, o));
 668 }
 669
 670 /*
 671  * Convert block (dablk) to block (DB)
 672  */
 673 static inline xfs_dir2_db_t
 674 xfs_dir2_da_to_db(struct xfs_mount *mp, xfs_dablk_t da)
 675 {
 676         return (xfs_dir2_db_t)(da >> mp->m_sb.sb_dirblklog);
 677 }
 678
 679 /*
 680  * Convert block (dablk) to byte offset in space
 681  */
 682 static inline xfs_dir2_off_t
 683 xfs_dir2_da_to_byte(struct xfs_mount *mp, xfs_dablk_t da)
 684 {
 685         return xfs_dir2_db_off_to_byte(mp, xfs_dir2_da_to_db(mp, da), 0);
 686 }
 687
 688 /*
 689  * Free space block defintions for the node format.
 690  */
 691
 692 /*
 693  * Offset of the freespace index.
 694  */
 695 #define XFS_DIR2_FREE_SPACE     2
 696 #define XFS_DIR2_FREE_OFFSET    (XFS_DIR2_FREE_SPACE * XFS_DIR2_SPACE_SIZE)
 697 #define XFS_DIR2_FREE_FIRSTDB(mp)       \
 698         xfs_dir2_byte_to_db(mp, XFS_DIR2_FREE_OFFSET)
 699
 700 typedef struct xfs_dir2_free_hdr {
 701         __be32                  magic;          /* XFS_DIR2_FREE_MAGIC */
 702         __be32                  firstdb;        /* db of first entry */
 703         __be32                  nvalid;         /* count of valid entries */
 704         __be32                  nused;          /* count of used entries */
 705 } xfs_dir2_free_hdr_t;
 706
 707 typedef struct xfs_dir2_free {
 708         xfs_dir2_free_hdr_t     hdr;            /* block header */
 709         __be16                  bests[];        /* best free counts */
 710                                                 /* unused entries are -1 */
 711 } xfs_dir2_free_t;
 712
 713 struct xfs_dir3_free_hdr {
 714         struct xfs_dir3_blk_hdr hdr;
 715         __be32                  firstdb;        /* db of first entry */
 716         __be32                  nvalid;         /* count of valid entries */
 717         __be32                  nused;          /* count of used entries */
 718         __be32                  pad;            /* 64 bit alignment. */
 719 };
 720
 721 struct xfs_dir3_free {
 722         struct xfs_dir3_free_hdr hdr;
 723         __be16                  bests[];        /* best free counts */
 724                                                 /* unused entries are -1 */
 725 };
 726
 727 #define XFS_DIR3_FREE_CRC_OFF  offsetof(struct xfs_dir3_free, hdr.hdr.crc)
 728
 729 /*
 730  * In core version of the free block header, abstracted away from on-disk format
 731  * differences. Use this in the code, and convert to/from the disk version using
 732  * xfs_dir3_free_hdr_from_disk/xfs_dir3_free_hdr_to_disk.
 733  */
 734 struct xfs_dir3_icfree_hdr {
 735         __uint32_t      magic;
 736         __uint32_t      firstdb;
 737         __uint32_t      nvalid;
 738         __uint32_t      nused;
 739
 740 };
 741
 742 void xfs_dir3_free_hdr_from_disk(struct xfs_dir3_icfree_hdr *to,
 743                                  struct xfs_dir2_free *from);
 744
 745 static inline int
 746 xfs_dir3_free_hdr_size(struct xfs_mount *mp)
 747 {
 748         if (xfs_sb_version_hascrc(&mp->m_sb))
 749                 return sizeof(struct xfs_dir3_free_hdr);
 750         return sizeof(struct xfs_dir2_free_hdr);
 751 }
 752
 753 static inline int
 754 xfs_dir3_free_max_bests(struct xfs_mount *mp)
 755 {
 756         return (mp->m_dirblksize - xfs_dir3_free_hdr_size(mp)) /
 757                 sizeof(xfs_dir2_data_off_t);
 758 }
 759
 760 static inline __be16 *
 761 xfs_dir3_free_bests_p(struct xfs_mount *mp, struct xfs_dir2_free *free)
 762 {
 763         return (__be16 *)((char *)free + xfs_dir3_free_hdr_size(mp));
 764 }
 765
 766 /*
 767  * Convert data space db to the corresponding free db.
 768  */
 769 static inline xfs_dir2_db_t
 770 xfs_dir2_db_to_fdb(struct xfs_mount *mp, xfs_dir2_db_t db)
 771 {
 772         return XFS_DIR2_FREE_FIRSTDB(mp) + db / xfs_dir3_free_max_bests(mp);
 773 }
 774
 775 /*
 776  * Convert data space db to the corresponding index in a free db.
 777  */
 778 static inline int
 779 xfs_dir2_db_to_fdindex(struct xfs_mount *mp, xfs_dir2_db_t db)
 780 {
 781         return db % xfs_dir3_free_max_bests(mp);
 782 }
 783
 784 /*
 785  * Single block format.
 786  *
 787  * The single block format looks like the following drawing on disk:
 788  *
 789  *    +-------------------------------------------------+
 790  *    | xfs_dir2_data_hdr_t                             |
 791  *    +-------------------------------------------------+
 792  *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 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  *    | ...                                             |
 796  *    +-------------------------------------------------+
 797  *    | unused space                                    |
 798  *    +-------------------------------------------------+
 799  *    | ...                                             |
 800  *    | xfs_dir2_leaf_entry_t                           |
 801  *    | xfs_dir2_leaf_entry_t                           |
 802  *    +-------------------------------------------------+
 803  *    | xfs_dir2_block_tail_t                           |
 804  *    +-------------------------------------------------+
 805  *
 806  * As all the entries are variable size structures the accessors below should
 807  * be used to iterate over them.
 808  */
 809
 810 typedef struct xfs_dir2_block_tail {
 811         __be32          count;                  /* count of leaf entries */
 812         __be32          stale;                  /* count of stale lf entries */
 813 } xfs_dir2_block_tail_t;
 814
 815 /*
 816  * Pointer to the leaf header embedded in a data block (1-block format)
 817  */
 818 static inline struct xfs_dir2_block_tail *
 819 xfs_dir2_block_tail_p(struct xfs_mount *mp, struct xfs_dir2_data_hdr *hdr)
 820 {
 821         return ((struct xfs_dir2_block_tail *)
 822                 ((char *)hdr + mp->m_dirblksize)) - 1;
 823 }
 824
 825 /*
 826  * Pointer to the leaf entries embedded in a data block (1-block format)
 827  */
 828 static inline struct xfs_dir2_leaf_entry *
 829 xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp)
 830 {
 831         return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count);
 832 }
 833
 834 #endif /* __XFS_DIR2_FORMAT_H__ */