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
  70 /*
  71  * Byte offset in data block and shortform entry.
  72  */
  73 typedef __uint16_t      xfs_dir2_data_off_t;
  74 #define NULLDATAOFF     0xffffU
  75 typedef uint            xfs_dir2_data_aoff_t;   /* argument form */
  76
  77 /*
  78  * Normalized offset (in a data block) of the entry, really xfs_dir2_data_off_t.
  79  * Only need 16 bits, this is the byte offset into the single block form.
  80  */
  81 typedef struct { __uint8_t i[2]; } __arch_pack xfs_dir2_sf_off_t;
  82
  83 /*
  84  * Offset in data space of a data entry.
  85  */
  86 typedef __uint32_t      xfs_dir2_dataptr_t;
  87 #define XFS_DIR2_MAX_DATAPTR    ((xfs_dir2_dataptr_t)0xffffffff)
  88 #define XFS_DIR2_NULL_DATAPTR   ((xfs_dir2_dataptr_t)0)
  89
  90 /*
  91  * Byte offset in a directory.
  92  */
  93 typedef xfs_off_t       xfs_dir2_off_t;
  94
  95 /*
  96  * Directory block number (logical dirblk in file)
  97  */
  98 typedef __uint32_t      xfs_dir2_db_t;
  99
 100 /*
 101  * Inode number stored as 8 8-bit values.
 102  */
 103 typedef struct { __uint8_t i[8]; } xfs_dir2_ino8_t;
 104
 105 /*
 106  * Inode number stored as 4 8-bit values.
 107  * Works a lot of the time, when all the inode numbers in a directory
 108  * fit in 32 bits.
 109  */
 110 typedef struct { __uint8_t i[4]; } xfs_dir2_ino4_t;
 111
 112 typedef union {
 113         xfs_dir2_ino8_t i8;
 114         xfs_dir2_ino4_t i4;
 115 } xfs_dir2_inou_t;
 116 #define XFS_DIR2_MAX_SHORT_INUM ((xfs_ino_t)0xffffffffULL)
 117
 118 /*
 119  * Directory layout when stored internal to an inode.
 120  *
 121  * Small directories are packed as tightly as possible so as to fit into the
 122  * literal area of the inode.  These "shortform" directories consist of a
 123  * single xfs_dir2_sf_hdr header followed by zero or more xfs_dir2_sf_entry
 124  * structures.  Due the different inode number storage size and the variable
 125  * length name field in the xfs_dir2_sf_entry all these structure are
 126  * variable length, and the accessors in this file should be used to iterate
 127  * over them.
 128  */
 129 typedef struct xfs_dir2_sf_hdr {
 130         __uint8_t               count;          /* count of entries */
 131         __uint8_t               i8count;        /* count of 8-byte inode #s */
 132         xfs_dir2_inou_t         parent;         /* parent dir inode number */
 133 } __arch_pack xfs_dir2_sf_hdr_t;
 134
 135 typedef struct xfs_dir2_sf_entry {
 136         __u8                    namelen;        /* actual name length */
 137         xfs_dir2_sf_off_t       offset;         /* saved offset */
 138         __u8                    name[];         /* name, variable size */
 139         /*
 140          * A xfs_dir2_ino8_t or xfs_dir2_ino4_t follows here, at a
 141          * variable offset after the name.
 142          */
 143 } __arch_pack xfs_dir2_sf_entry_t;
 144
 145 static inline int xfs_dir2_sf_hdr_size(int i8count)
 146 {
 147         return sizeof(struct xfs_dir2_sf_hdr) -
 148                 (i8count == 0) *
 149                 (sizeof(xfs_dir2_ino8_t) - sizeof(xfs_dir2_ino4_t));
 150 }
 151
 152 static inline xfs_dir2_data_aoff_t
 153 xfs_dir2_sf_get_offset(xfs_dir2_sf_entry_t *sfep)
 154 {
 155         return get_unaligned_be16(&sfep->offset.i);
 156 }
 157
 158 static inline void
 159 xfs_dir2_sf_put_offset(xfs_dir2_sf_entry_t *sfep, xfs_dir2_data_aoff_t off)
 160 {
 161         put_unaligned_be16(off, &sfep->offset.i);
 162 }
 163
 164 static inline int
 165 xfs_dir2_sf_entsize(struct xfs_dir2_sf_hdr *hdr, int len)
 166 {
 167         return sizeof(struct xfs_dir2_sf_entry) +       /* namelen + offset */
 168                 len +                                   /* name */
 169                 (hdr->i8count ?                         /* ino */
 170                  sizeof(xfs_dir2_ino8_t) :
 171                  sizeof(xfs_dir2_ino4_t));
 172 }
 173
 174 static inline struct xfs_dir2_sf_entry *
 175 xfs_dir2_sf_firstentry(struct xfs_dir2_sf_hdr *hdr)
 176 {
 177         return (struct xfs_dir2_sf_entry *)
 178                 ((char *)hdr + xfs_dir2_sf_hdr_size(hdr->i8count));
 179 }
 180
 181 static inline struct xfs_dir2_sf_entry *
 182 xfs_dir2_sf_nextentry(struct xfs_dir2_sf_hdr *hdr,
 183                 struct xfs_dir2_sf_entry *sfep)
 184 {
 185         return (struct xfs_dir2_sf_entry *)
 186                 ((char *)sfep + xfs_dir2_sf_entsize(hdr, sfep->namelen));
 187 }
 188
 189
 190 /*
 191  * Data block structures.
 192  *
 193  * A pure data block looks like the following drawing on disk:
 194  *
 195  *    +-------------------------------------------------+
 196  *    | xfs_dir2_data_hdr_t                             |
 197  *    +-------------------------------------------------+
 198  *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 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  *    | ...                                             |
 202  *    +-------------------------------------------------+
 203  *    | unused space                                    |
 204  *    +-------------------------------------------------+
 205  *
 206  * As all the entries are variable size structures the accessors below should
 207  * be used to iterate over them.
 208  *
 209  * In addition to the pure data blocks for the data and node formats,
 210  * most structures are also used for the combined data/freespace "block"
 211  * format below.
 212  */
 213
 214 #define XFS_DIR2_DATA_ALIGN_LOG 3               /* i.e., 8 bytes */
 215 #define XFS_DIR2_DATA_ALIGN     (1 << XFS_DIR2_DATA_ALIGN_LOG)
 216 #define XFS_DIR2_DATA_FREE_TAG  0xffff
 217 #define XFS_DIR2_DATA_FD_COUNT  3
 218
 219 /*
 220  * Directory address space divided into sections,
 221  * spaces separated by 32GB.
 222  */
 223 #define XFS_DIR2_SPACE_SIZE     (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
 224 #define XFS_DIR2_DATA_SPACE     0
 225 #define XFS_DIR2_DATA_OFFSET    (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE)
 226 #define XFS_DIR2_DATA_FIRSTDB(mp)       \
 227         xfs_dir2_byte_to_db(mp, XFS_DIR2_DATA_OFFSET)
 228
 229 /*
 230  * Offsets of . and .. in data space (always block 0)
 231  */
 232 #define XFS_DIR2_DATA_DOT_OFFSET        \
 233         ((xfs_dir2_data_aoff_t)sizeof(struct xfs_dir2_data_hdr))
 234 #define XFS_DIR2_DATA_DOTDOT_OFFSET     \
 235         (XFS_DIR2_DATA_DOT_OFFSET + xfs_dir2_data_entsize(1))
 236 #define XFS_DIR2_DATA_FIRST_OFFSET              \
 237         (XFS_DIR2_DATA_DOTDOT_OFFSET + xfs_dir2_data_entsize(2))
 238
 239 /*
 240  * Describe a free area in the data block.
 241  *
 242  * The freespace will be formatted as a xfs_dir2_data_unused_t.
 243  */
 244 typedef struct xfs_dir2_data_free {
 245         __be16                  offset;         /* start of freespace */
 246         __be16                  length;         /* length of freespace */
 247 } xfs_dir2_data_free_t;
 248
 249 /*
 250  * Header for the data blocks.
 251  *
 252  * The code knows that XFS_DIR2_DATA_FD_COUNT is 3.
 253  */
 254 typedef struct xfs_dir2_data_hdr {
 255         __be32                  magic;          /* XFS_DIR2_DATA_MAGIC or */
 256                                                 /* XFS_DIR2_BLOCK_MAGIC */
 257         xfs_dir2_data_free_t    bestfree[XFS_DIR2_DATA_FD_COUNT];
 258 } xfs_dir2_data_hdr_t;
 259
 260 /*
 261  * define a structure for all the verification fields we are adding to the
 262  * directory block structures. This will be used in several structures.
 263  * The magic number must be the first entry to align with all the dir2
 264  * structures so we determine how to decode them just by the magic number.
 265  */
 266 struct xfs_dir3_blk_hdr {
 267         __be32                  magic;  /* magic number */
 268         __be32                  crc;    /* CRC of block */
 269         __be64                  blkno;  /* first block of the buffer */
 270         __be64                  lsn;    /* sequence number of last write */
 271         uuid_t                  uuid;   /* filesystem we belong to */
 272         __be64                  owner;  /* inode that owns the block */
 273 };
 274
 275 struct xfs_dir3_data_hdr {
 276         struct xfs_dir3_blk_hdr hdr;
 277         xfs_dir2_data_free_t    best_free[XFS_DIR2_DATA_FD_COUNT];
 278 };
 279
 280 #define XFS_DIR3_DATA_CRC_OFF  offsetof(struct xfs_dir3_data_hdr, hdr.crc)
 281
 282 static inline struct xfs_dir2_data_free *
 283 xfs_dir3_data_bestfree_p(struct xfs_dir2_data_hdr *hdr)
 284 {
 285         if (hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
 286                 struct xfs_dir3_data_hdr *hdr3 = (struct xfs_dir3_data_hdr *)hdr;
 287                 return hdr3->best_free;
 288         }
 289         return hdr->bestfree;
 290 }
 291
 292 /*
 293  * Active entry in a data block.
 294  *
 295  * Aligned to 8 bytes.  After the variable length name field there is a
 296  * 2 byte tag field, which can be accessed using xfs_dir2_data_entry_tag_p.
 297  */
 298 typedef struct xfs_dir2_data_entry {
 299         __be64                  inumber;        /* inode number */
 300         __u8                    namelen;        /* name length */
 301         __u8                    name[];         /* name bytes, no null */
 302      /* __be16                  tag; */         /* starting offset of us */
 303 } xfs_dir2_data_entry_t;
 304
 305 /*
 306  * Unused entry in a data block.
 307  *
 308  * Aligned to 8 bytes.  Tag appears as the last 2 bytes and must be accessed
 309  * using xfs_dir2_data_unused_tag_p.
 310  */
 311 typedef struct xfs_dir2_data_unused {
 312         __be16                  freetag;        /* XFS_DIR2_DATA_FREE_TAG */
 313         __be16                  length;         /* total free length */
 314                                                 /* variable offset */
 315         __be16                  tag;            /* starting offset of us */
 316 } xfs_dir2_data_unused_t;
 317
 318 /*
 319  * Size of a data entry.
 320  */
 321 static inline int xfs_dir2_data_entsize(int n)
 322 {
 323         return (int)roundup(offsetof(struct xfs_dir2_data_entry, name[0]) + n +
 324                  (uint)sizeof(xfs_dir2_data_off_t), XFS_DIR2_DATA_ALIGN);
 325 }
 326
 327 /*
 328  * Pointer to an entry's tag word.
 329  */
 330 static inline __be16 *
 331 xfs_dir2_data_entry_tag_p(struct xfs_dir2_data_entry *dep)
 332 {
 333         return (__be16 *)((char *)dep +
 334                 xfs_dir2_data_entsize(dep->namelen) - sizeof(__be16));
 335 }
 336
 337 /*
 338  * Pointer to a freespace's tag word.
 339  */
 340 static inline __be16 *
 341 xfs_dir2_data_unused_tag_p(struct xfs_dir2_data_unused *dup)
 342 {
 343         return (__be16 *)((char *)dup +
 344                         be16_to_cpu(dup->length) - sizeof(__be16));
 345 }
 346
 347 static inline struct xfs_dir2_data_unused *
 348 xfs_dir3_data_unused_p(struct xfs_dir2_data_hdr *hdr)
 349 {
 350         if (hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC)) {
 351                 return (struct xfs_dir2_data_unused *)
 352                         ((char *)hdr + sizeof(struct xfs_dir3_data_hdr));
 353         }
 354         return (struct xfs_dir2_data_unused *)
 355                 ((char *)hdr + sizeof(struct xfs_dir2_data_hdr));
 356 }
 357
 358 static inline size_t
 359 xfs_dir3_data_hdr_size(bool dir3)
 360 {
 361         if (dir3)
 362                 return sizeof(struct xfs_dir3_data_hdr);
 363         return sizeof(struct xfs_dir2_data_hdr);
 364 }
 365
 366 static inline size_t
 367 xfs_dir3_data_entry_offset(struct xfs_dir2_data_hdr *hdr)
 368 {
 369         bool dir3 = hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC) ||
 370                     hdr->magic == cpu_to_be32(XFS_DIR3_BLOCK_MAGIC);
 371         return xfs_dir3_data_hdr_size(dir3);
 372 }
 373
 374 static inline struct xfs_dir2_data_entry *
 375 xfs_dir3_data_entry_p(struct xfs_dir2_data_hdr *hdr)
 376 {
 377         return (struct xfs_dir2_data_entry *)
 378                 ((char *)hdr + xfs_dir3_data_entry_offset(hdr));
 379 }
 380
 381 /*
 382  * Offsets of . and .. in data space (always block 0)
 383  */
 384 static inline xfs_dir2_data_aoff_t
 385 xfs_dir3_data_dot_offset(struct xfs_dir2_data_hdr *hdr)
 386 {
 387         return xfs_dir3_data_entry_offset(hdr);
 388 }
 389
 390 static inline xfs_dir2_data_aoff_t
 391 xfs_dir3_data_dotdot_offset(struct xfs_dir2_data_hdr *hdr)
 392 {
 393         return xfs_dir3_data_dot_offset(hdr) + xfs_dir2_data_entsize(1);
 394 }
 395
 396 static inline xfs_dir2_data_aoff_t
 397 xfs_dir3_data_first_offset(struct xfs_dir2_data_hdr *hdr)
 398 {
 399         return xfs_dir3_data_dotdot_offset(hdr) + xfs_dir2_data_entsize(2);
 400 }
 401
 402 /*
 403  * location of . and .. in data space (always block 0)
 404  */
 405 static inline struct xfs_dir2_data_entry *
 406 xfs_dir3_data_dot_entry_p(struct xfs_dir2_data_hdr *hdr)
 407 {
 408         return (struct xfs_dir2_data_entry *)
 409                 ((char *)hdr + xfs_dir3_data_dot_offset(hdr));
 410 }
 411
 412 static inline struct xfs_dir2_data_entry *
 413 xfs_dir3_data_dotdot_entry_p(struct xfs_dir2_data_hdr *hdr)
 414 {
 415         return (struct xfs_dir2_data_entry *)
 416                 ((char *)hdr + xfs_dir3_data_dotdot_offset(hdr));
 417 }
 418
 419 static inline struct xfs_dir2_data_entry *
 420 xfs_dir3_data_first_entry_p(struct xfs_dir2_data_hdr *hdr)
 421 {
 422         return (struct xfs_dir2_data_entry *)
 423                 ((char *)hdr + xfs_dir3_data_first_offset(hdr));
 424 }
 425
 426 /*
 427  * Leaf block structures.
 428  *
 429  * A pure leaf block looks like the following drawing on disk:
 430  *
 431  *    +---------------------------+
 432  *    | xfs_dir2_leaf_hdr_t       |
 433  *    +---------------------------+
 434  *    | xfs_dir2_leaf_entry_t     |
 435  *    | xfs_dir2_leaf_entry_t     |
 436  *    | xfs_dir2_leaf_entry_t     |
 437  *    | xfs_dir2_leaf_entry_t     |
 438  *    | ...                       |
 439  *    +---------------------------+
 440  *    | xfs_dir2_data_off_t       |
 441  *    | xfs_dir2_data_off_t       |
 442  *    | xfs_dir2_data_off_t       |
 443  *    | ...                       |
 444  *    +---------------------------+
 445  *    | xfs_dir2_leaf_tail_t      |
 446  *    +---------------------------+
 447  *
 448  * The xfs_dir2_data_off_t members (bests) and tail are at the end of the block
 449  * for single-leaf (magic = XFS_DIR2_LEAF1_MAGIC) blocks only, but not present
 450  * for directories with separate leaf nodes and free space blocks
 451  * (magic = XFS_DIR2_LEAFN_MAGIC).
 452  *
 453  * As all the entries are variable size structures the accessors below should
 454  * be used to iterate over them.
 455  */
 456
 457 /*
 458  * Offset of the leaf/node space.  First block in this space
 459  * is the btree root.
 460  */
 461 #define XFS_DIR2_LEAF_SPACE     1
 462 #define XFS_DIR2_LEAF_OFFSET    (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE)
 463 #define XFS_DIR2_LEAF_FIRSTDB(mp)       \
 464         xfs_dir2_byte_to_db(mp, XFS_DIR2_LEAF_OFFSET)
 465
 466 /*
 467  * Leaf block header.
 468  */
 469 typedef struct xfs_dir2_leaf_hdr {
 470         xfs_da_blkinfo_t        info;           /* header for da routines */
 471         __be16                  count;          /* count of entries */
 472         __be16                  stale;          /* count of stale entries */
 473 } xfs_dir2_leaf_hdr_t;
 474
 475 /*
 476  * Leaf block entry.
 477  */
 478 typedef struct xfs_dir2_leaf_entry {
 479         __be32                  hashval;        /* hash value of name */
 480         __be32                  address;        /* address of data entry */
 481 } xfs_dir2_leaf_entry_t;
 482
 483 /*
 484  * Leaf block tail.
 485  */
 486 typedef struct xfs_dir2_leaf_tail {
 487         __be32                  bestcount;
 488 } xfs_dir2_leaf_tail_t;
 489
 490 /*
 491  * Leaf block.
 492  */
 493 typedef struct xfs_dir2_leaf {
 494         xfs_dir2_leaf_hdr_t     hdr;            /* leaf header */
 495         xfs_dir2_leaf_entry_t   ents[];         /* entries */
 496 } xfs_dir2_leaf_t;
 497
 498 /*
 499  * DB blocks here are logical directory block numbers, not filesystem blocks.
 500  */
 501
 502 static inline int xfs_dir2_max_leaf_ents(struct xfs_mount *mp)
 503 {
 504         return (mp->m_dirblksize - (uint)sizeof(struct xfs_dir2_leaf_hdr)) /
 505                 (uint)sizeof(struct xfs_dir2_leaf_entry);
 506 }
 507
 508 /*
 509  * Get address of the bestcount field in the single-leaf block.
 510  */
 511 static inline struct xfs_dir2_leaf_tail *
 512 xfs_dir2_leaf_tail_p(struct xfs_mount *mp, struct xfs_dir2_leaf *lp)
 513 {
 514         return (struct xfs_dir2_leaf_tail *)
 515                 ((char *)lp + mp->m_dirblksize -
 516                   sizeof(struct xfs_dir2_leaf_tail));
 517 }
 518
 519 /*
 520  * Get address of the bests array in the single-leaf block.
 521  */
 522 static inline __be16 *
 523 xfs_dir2_leaf_bests_p(struct xfs_dir2_leaf_tail *ltp)
 524 {
 525         return (__be16 *)ltp - be32_to_cpu(ltp->bestcount);
 526 }
 527
 528 /*
 529  * Convert dataptr to byte in file space
 530  */
 531 static inline xfs_dir2_off_t
 532 xfs_dir2_dataptr_to_byte(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
 533 {
 534         return (xfs_dir2_off_t)dp << XFS_DIR2_DATA_ALIGN_LOG;
 535 }
 536
 537 /*
 538  * Convert byte in file space to dataptr.  It had better be aligned.
 539  */
 540 static inline xfs_dir2_dataptr_t
 541 xfs_dir2_byte_to_dataptr(struct xfs_mount *mp, xfs_dir2_off_t by)
 542 {
 543         return (xfs_dir2_dataptr_t)(by >> XFS_DIR2_DATA_ALIGN_LOG);
 544 }
 545
 546 /*
 547  * Convert byte in space to (DB) block
 548  */
 549 static inline xfs_dir2_db_t
 550 xfs_dir2_byte_to_db(struct xfs_mount *mp, xfs_dir2_off_t by)
 551 {
 552         return (xfs_dir2_db_t)
 553                 (by >> (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog));
 554 }
 555
 556 /*
 557  * Convert dataptr to a block number
 558  */
 559 static inline xfs_dir2_db_t
 560 xfs_dir2_dataptr_to_db(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
 561 {
 562         return xfs_dir2_byte_to_db(mp, xfs_dir2_dataptr_to_byte(mp, dp));
 563 }
 564
 565 /*
 566  * Convert byte in space to offset in a block
 567  */
 568 static inline xfs_dir2_data_aoff_t
 569 xfs_dir2_byte_to_off(struct xfs_mount *mp, xfs_dir2_off_t by)
 570 {
 571         return (xfs_dir2_data_aoff_t)(by &
 572                 ((1 << (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) - 1));
 573 }
 574
 575 /*
 576  * Convert dataptr to a byte offset in a block
 577  */
 578 static inline xfs_dir2_data_aoff_t
 579 xfs_dir2_dataptr_to_off(struct xfs_mount *mp, xfs_dir2_dataptr_t dp)
 580 {
 581         return xfs_dir2_byte_to_off(mp, xfs_dir2_dataptr_to_byte(mp, dp));
 582 }
 583
 584 /*
 585  * Convert block and offset to byte in space
 586  */
 587 static inline xfs_dir2_off_t
 588 xfs_dir2_db_off_to_byte(struct xfs_mount *mp, xfs_dir2_db_t db,
 589                         xfs_dir2_data_aoff_t o)
 590 {
 591         return ((xfs_dir2_off_t)db <<
 592                 (mp->m_sb.sb_blocklog + mp->m_sb.sb_dirblklog)) + o;
 593 }
 594
 595 /*
 596  * Convert block (DB) to block (dablk)
 597  */
 598 static inline xfs_dablk_t
 599 xfs_dir2_db_to_da(struct xfs_mount *mp, xfs_dir2_db_t db)
 600 {
 601         return (xfs_dablk_t)(db << mp->m_sb.sb_dirblklog);
 602 }
 603
 604 /*
 605  * Convert byte in space to (DA) block
 606  */
 607 static inline xfs_dablk_t
 608 xfs_dir2_byte_to_da(struct xfs_mount *mp, xfs_dir2_off_t by)
 609 {
 610         return xfs_dir2_db_to_da(mp, xfs_dir2_byte_to_db(mp, by));
 611 }
 612
 613 /*
 614  * Convert block and offset to dataptr
 615  */
 616 static inline xfs_dir2_dataptr_t
 617 xfs_dir2_db_off_to_dataptr(struct xfs_mount *mp, xfs_dir2_db_t db,
 618                            xfs_dir2_data_aoff_t o)
 619 {
 620         return xfs_dir2_byte_to_dataptr(mp, xfs_dir2_db_off_to_byte(mp, db, o));
 621 }
 622
 623 /*
 624  * Convert block (dablk) to block (DB)
 625  */
 626 static inline xfs_dir2_db_t
 627 xfs_dir2_da_to_db(struct xfs_mount *mp, xfs_dablk_t da)
 628 {
 629         return (xfs_dir2_db_t)(da >> mp->m_sb.sb_dirblklog);
 630 }
 631
 632 /*
 633  * Convert block (dablk) to byte offset in space
 634  */
 635 static inline xfs_dir2_off_t
 636 xfs_dir2_da_to_byte(struct xfs_mount *mp, xfs_dablk_t da)
 637 {
 638         return xfs_dir2_db_off_to_byte(mp, xfs_dir2_da_to_db(mp, da), 0);
 639 }
 640
 641 /*
 642  * Free space block defintions for the node format.
 643  */
 644
 645 /*
 646  * Offset of the freespace index.
 647  */
 648 #define XFS_DIR2_FREE_SPACE     2
 649 #define XFS_DIR2_FREE_OFFSET    (XFS_DIR2_FREE_SPACE * XFS_DIR2_SPACE_SIZE)
 650 #define XFS_DIR2_FREE_FIRSTDB(mp)       \
 651         xfs_dir2_byte_to_db(mp, XFS_DIR2_FREE_OFFSET)
 652
 653 typedef struct xfs_dir2_free_hdr {
 654         __be32                  magic;          /* XFS_DIR2_FREE_MAGIC */
 655         __be32                  firstdb;        /* db of first entry */
 656         __be32                  nvalid;         /* count of valid entries */
 657         __be32                  nused;          /* count of used entries */
 658 } xfs_dir2_free_hdr_t;
 659
 660 typedef struct xfs_dir2_free {
 661         xfs_dir2_free_hdr_t     hdr;            /* block header */
 662         __be16                  bests[];        /* best free counts */
 663                                                 /* unused entries are -1 */
 664 } xfs_dir2_free_t;
 665
 666 static inline int xfs_dir2_free_max_bests(struct xfs_mount *mp)
 667 {
 668         return (mp->m_dirblksize - sizeof(struct xfs_dir2_free_hdr)) /
 669                 sizeof(xfs_dir2_data_off_t);
 670 }
 671
 672 /*
 673  * Convert data space db to the corresponding free db.
 674  */
 675 static inline xfs_dir2_db_t
 676 xfs_dir2_db_to_fdb(struct xfs_mount *mp, xfs_dir2_db_t db)
 677 {
 678         return XFS_DIR2_FREE_FIRSTDB(mp) + db / xfs_dir2_free_max_bests(mp);
 679 }
 680
 681 /*
 682  * Convert data space db to the corresponding index in a free db.
 683  */
 684 static inline int
 685 xfs_dir2_db_to_fdindex(struct xfs_mount *mp, xfs_dir2_db_t db)
 686 {
 687         return db % xfs_dir2_free_max_bests(mp);
 688 }
 689
 690 /*
 691  * Single block format.
 692  *
 693  * The single block format looks like the following drawing on disk:
 694  *
 695  *    +-------------------------------------------------+
 696  *    | xfs_dir2_data_hdr_t                             |
 697  *    +-------------------------------------------------+
 698  *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 699  *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t |
 700  *    | xfs_dir2_data_entry_t OR xfs_dir2_data_unused_t :
 701  *    | ...                                             |
 702  *    +-------------------------------------------------+
 703  *    | unused space                                    |
 704  *    +-------------------------------------------------+
 705  *    | ...                                             |
 706  *    | xfs_dir2_leaf_entry_t                           |
 707  *    | xfs_dir2_leaf_entry_t                           |
 708  *    +-------------------------------------------------+
 709  *    | xfs_dir2_block_tail_t                           |
 710  *    +-------------------------------------------------+
 711  *
 712  * As all the entries are variable size structures the accessors below should
 713  * be used to iterate over them.
 714  */
 715
 716 typedef struct xfs_dir2_block_tail {
 717         __be32          count;                  /* count of leaf entries */
 718         __be32          stale;                  /* count of stale lf entries */
 719 } xfs_dir2_block_tail_t;
 720
 721 /*
 722  * Pointer to the leaf header embedded in a data block (1-block format)
 723  */
 724 static inline struct xfs_dir2_block_tail *
 725 xfs_dir2_block_tail_p(struct xfs_mount *mp, struct xfs_dir2_data_hdr *hdr)
 726 {
 727         return ((struct xfs_dir2_block_tail *)
 728                 ((char *)hdr + mp->m_dirblksize)) - 1;
 729 }
 730
 731 /*
 732  * Pointer to the leaf entries embedded in a data block (1-block format)
 733  */
 734 static inline struct xfs_dir2_leaf_entry *
 735 xfs_dir2_block_leaf_p(struct xfs_dir2_block_tail *btp)
 736 {
 737         return ((struct xfs_dir2_leaf_entry *)btp) - be32_to_cpu(btp->count);
 738 }
 739
 740 #endif /* __XFS_DIR2_FORMAT_H__ */