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_btree_sblock;
  28 struct xfs_mount;
  29
  30 /*
  31  * There are two on-disk btrees, one sorted by blockno and one sorted
  32  * by blockcount and blockno.  All blocks look the same to make the code
  33  * simpler; if we have time later, we'll make the optimizations.
  34  */
  35 #define XFS_ABTB_MAGIC  0x41425442      /* 'ABTB' for bno tree */
  36 #define XFS_ABTC_MAGIC  0x41425443      /* 'ABTC' for cnt tree */
  37
  38 /*
  39  * Data record/key structure
  40  */
  41 typedef struct xfs_alloc_rec {
  42         __be32          ar_startblock;  /* starting block number */
  43         __be32          ar_blockcount;  /* count of free blocks */
  44 } xfs_alloc_rec_t, xfs_alloc_key_t;
  45
  46 typedef struct xfs_alloc_rec_incore {
  47         xfs_agblock_t   ar_startblock;  /* starting block number */
  48         xfs_extlen_t    ar_blockcount;  /* count of free blocks */
  49 } xfs_alloc_rec_incore_t;
  50
  51 /* btree pointer type */
  52 typedef __be32 xfs_alloc_ptr_t;
  53 /* btree block header type */
  54 typedef struct xfs_btree_sblock xfs_alloc_block_t;
  55
  56 #define XFS_BUF_TO_ALLOC_BLOCK(bp)      ((xfs_alloc_block_t *)XFS_BUF_PTR(bp))
  57
  58 /*
  59  * Minimum and maximum blocksize and sectorsize.
  60  * The blocksize upper limit is pretty much arbitrary.
  61  * The sectorsize upper limit is due to sizeof(sb_sectsize).
  62  */
  63 #define XFS_MIN_BLOCKSIZE_LOG   9       /* i.e. 512 bytes */
  64 #define XFS_MAX_BLOCKSIZE_LOG   16      /* i.e. 65536 bytes */
  65 #define XFS_MIN_BLOCKSIZE       (1 << XFS_MIN_BLOCKSIZE_LOG)
  66 #define XFS_MAX_BLOCKSIZE       (1 << XFS_MAX_BLOCKSIZE_LOG)
  67 #define XFS_MIN_SECTORSIZE_LOG  9       /* i.e. 512 bytes */
  68 #define XFS_MAX_SECTORSIZE_LOG  15      /* i.e. 32768 bytes */
  69 #define XFS_MIN_SECTORSIZE      (1 << XFS_MIN_SECTORSIZE_LOG)
  70 #define XFS_MAX_SECTORSIZE      (1 << XFS_MAX_SECTORSIZE_LOG)
  71
  72 /*
  73  * Block numbers in the AG:
  74  * SB is sector 0, AGF is sector 1, AGI is sector 2, AGFL is sector 3.
  75  */
  76 #define XFS_BNO_BLOCK(mp)       ((xfs_agblock_t)(XFS_AGFL_BLOCK(mp) + 1))
  77 #define XFS_CNT_BLOCK(mp)       ((xfs_agblock_t)(XFS_BNO_BLOCK(mp) + 1))
  78
  79 /*
  80  * Record, key, and pointer address macros for btree blocks.
  81  */
  82 #define XFS_ALLOC_REC_ADDR(bb,i,cur)    \
  83         XFS_BTREE_REC_ADDR(xfs_alloc, bb, i)
  84
  85 #define XFS_ALLOC_KEY_ADDR(bb,i,cur)    \
  86         XFS_BTREE_KEY_ADDR(xfs_alloc, bb, i)
  87
  88 #define XFS_ALLOC_PTR_ADDR(bb,i,cur)    \
  89         XFS_BTREE_PTR_ADDR(xfs_alloc, bb, i, XFS_ALLOC_BLOCK_MAXRECS(1, cur))
  90
  91
  92 extern struct xfs_btree_cur *xfs_allocbt_init_cursor(struct xfs_mount *,
  93                 struct xfs_trans *, struct xfs_buf *,
  94                 xfs_agnumber_t, xfs_btnum_t);
  95 extern int xfs_allocbt_maxrecs(struct xfs_mount *, int, int);
  96
  97 #endif  /* __XFS_ALLOC_BTREE_H__ */