fs/xfs/xfs_alloc_btree.h

   1 /*
   2  * Copyright (c) 2000,2005 Silicon Graphics, Inc.
   3  * All Rights Reserved.
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write the Free Software Foundation,
  16  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  17  */
  18 #ifndef __XFS_ALLOC_BTREE_H__
  19 #define __XFS_ALLOC_BTREE_H__
  20
  21 /*
  22  * Freespace on-disk structures
  23  */
  24
  25 struct xfs_buf;
  26 struct xfs_btree_cur;
  27 struct xfs_mount;
  28
  29 /*
  30  * There are two on-disk btrees, one sorted by blockno and one sorted
  31  * by blockcount and blockno.  All blocks look the same to make the code
  32  * simpler; if we have time later, we'll make the optimizations.
  33  */
  34 #define XFS_ABTB_MAGIC  0x41425442      /* 'ABTB' for bno tree */
  35 #define XFS_ABTC_MAGIC  0x41425443      /* 'ABTC' for cnt tree */
  36
  37 /*
  38  * Data record/key structure
  39  */
  40 typedef struct xfs_alloc_rec {
  41         __be32          ar_startblock;  /* starting block number */
  42         __be32          ar_blockcount;  /* count of free blocks */
  43 } xfs_alloc_rec_t, xfs_alloc_key_t;
  44
  45 typedef struct xfs_alloc_rec_incore {
  46         xfs_agblock_t   ar_startblock;  /* starting block number */
  47         xfs_extlen_t    ar_blockcount;  /* count of free blocks */
  48 } xfs_alloc_rec_incore_t;
  49
  50 /* btree pointer type */
  51 typedef __be32 xfs_alloc_ptr_t;
  52
  53 /*
  54  * Minimum and maximum blocksize and sectorsize.
  55  * The blocksize upper limit is pretty much arbitrary.
  56  * The sectorsize upper limit is due to sizeof(sb_sectsize).
  57  */
  58 #define XFS_MIN_BLOCKSIZE_LOG   9       /* i.e. 512 bytes */
  59 #define XFS_MAX_BLOCKSIZE_LOG   16      /* i.e. 65536 bytes */
  60 #define XFS_MIN_BLOCKSIZE       (1 << XFS_MIN_BLOCKSIZE_LOG)
  61 #define XFS_MAX_BLOCKSIZE       (1 << XFS_MAX_BLOCKSIZE_LOG)
  62 #define XFS_MIN_SECTORSIZE_LOG  9       /* i.e. 512 bytes */
  63 #define XFS_MAX_SECTORSIZE_LOG  15      /* i.e. 32768 bytes */
  64 #define XFS_MIN_SECTORSIZE      (1 << XFS_MIN_SECTORSIZE_LOG)
  65 #define XFS_MAX_SECTORSIZE      (1 << XFS_MAX_SECTORSIZE_LOG)
  66
  67 /*
  68  * Block numbers in the AG:
  69  * SB is sector 0, AGF is sector 1, AGI is sector 2, AGFL is sector 3.
  70  */
  71 #define XFS_BNO_BLOCK(mp)       ((xfs_agblock_t)(XFS_AGFL_BLOCK(mp) + 1))
  72 #define XFS_CNT_BLOCK(mp)       ((xfs_agblock_t)(XFS_BNO_BLOCK(mp) + 1))
  73
  74 /*
  75  * Btree block header size depends on a superblock flag.
  76  *
  77  * (not quite yet, but soon)
  78  */
  79 #define XFS_ALLOC_BLOCK_LEN(mp) XFS_BTREE_SBLOCK_LEN
  80
  81 /*
  82  * Record, key, and pointer address macros for btree blocks.
  83  *
  84  * (note that some of these may appear unused, but they are used in userspace)
  85  */
  86 #define XFS_ALLOC_REC_ADDR(mp, block, index) \
  87         ((xfs_alloc_rec_t *) \
  88                 ((char *)(block) + \
  89                  XFS_ALLOC_BLOCK_LEN(mp) + \
  90                  (((index) - 1) * sizeof(xfs_alloc_rec_t))))
  91
  92 #define XFS_ALLOC_KEY_ADDR(mp, block, index) \
  93         ((xfs_alloc_key_t *) \
  94                 ((char *)(block) + \
  95                  XFS_ALLOC_BLOCK_LEN(mp) + \
  96                  ((index) - 1) * sizeof(xfs_alloc_key_t)))
  97
  98 #define XFS_ALLOC_PTR_ADDR(mp, block, index, maxrecs) \
  99         ((xfs_alloc_ptr_t *) \
 100                 ((char *)(block) + \
 101                  XFS_ALLOC_BLOCK_LEN(mp) + \
 102                  (maxrecs) * sizeof(xfs_alloc_key_t) + \
 103                  ((index) - 1) * sizeof(xfs_alloc_ptr_t)))
 104
 105 extern struct xfs_btree_cur *xfs_allocbt_init_cursor(struct xfs_mount *,
 106                 struct xfs_trans *, struct xfs_buf *,
 107                 xfs_agnumber_t, xfs_btnum_t);
 108 extern int xfs_allocbt_maxrecs(struct xfs_mount *, int, int);
 109
 110 #endif  /* __XFS_ALLOC_BTREE_H__ */