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  * Real block structures have a size equal to the disk block size.
  60  */
  61 #define XFS_ALLOC_BLOCK_SIZE(lev,cur)   (1 << (cur)->bc_blocklog)
  62 #define XFS_ALLOC_BLOCK_MAXRECS(lev,cur) ((cur)->bc_mp->m_alloc_mxr[lev != 0])
  63 #define XFS_ALLOC_BLOCK_MINRECS(lev,cur) ((cur)->bc_mp->m_alloc_mnr[lev != 0])
  64
  65 /*
  66  * Minimum and maximum blocksize and sectorsize.
  67  * The blocksize upper limit is pretty much arbitrary.
  68  * The sectorsize upper limit is due to sizeof(sb_sectsize).
  69  */
  70 #define XFS_MIN_BLOCKSIZE_LOG   9       /* i.e. 512 bytes */
  71 #define XFS_MAX_BLOCKSIZE_LOG   16      /* i.e. 65536 bytes */
  72 #define XFS_MIN_BLOCKSIZE       (1 << XFS_MIN_BLOCKSIZE_LOG)
  73 #define XFS_MAX_BLOCKSIZE       (1 << XFS_MAX_BLOCKSIZE_LOG)
  74 #define XFS_MIN_SECTORSIZE_LOG  9       /* i.e. 512 bytes */
  75 #define XFS_MAX_SECTORSIZE_LOG  15      /* i.e. 32768 bytes */
  76 #define XFS_MIN_SECTORSIZE      (1 << XFS_MIN_SECTORSIZE_LOG)
  77 #define XFS_MAX_SECTORSIZE      (1 << XFS_MAX_SECTORSIZE_LOG)
  78
  79 /*
  80  * Block numbers in the AG:
  81  * SB is sector 0, AGF is sector 1, AGI is sector 2, AGFL is sector 3.
  82  */
  83 #define XFS_BNO_BLOCK(mp)       ((xfs_agblock_t)(XFS_AGFL_BLOCK(mp) + 1))
  84 #define XFS_CNT_BLOCK(mp)       ((xfs_agblock_t)(XFS_BNO_BLOCK(mp) + 1))
  85
  86 /*
  87  * Record, key, and pointer address macros for btree blocks.
  88  */
  89 #define XFS_ALLOC_REC_ADDR(bb,i,cur)    \
  90         XFS_BTREE_REC_ADDR(XFS_ALLOC_BLOCK_SIZE(0,cur), xfs_alloc, \
  91                                 bb, i, XFS_ALLOC_BLOCK_MAXRECS(0, cur))
  92
  93 #define XFS_ALLOC_KEY_ADDR(bb,i,cur)    \
  94         XFS_BTREE_KEY_ADDR(XFS_ALLOC_BLOCK_SIZE(1,cur), xfs_alloc, \
  95                                 bb, i, XFS_ALLOC_BLOCK_MAXRECS(1, cur))
  96
  97 #define XFS_ALLOC_PTR_ADDR(bb,i,cur)    \
  98         XFS_BTREE_PTR_ADDR(XFS_ALLOC_BLOCK_SIZE(1,cur), xfs_alloc, \
  99                                 bb, i, XFS_ALLOC_BLOCK_MAXRECS(1, cur))
 100
 101 /*
 102  * Decrement cursor by one record at the level.
 103  * For nonzero levels the leaf-ward information is untouched.
 104  */
 105 extern int xfs_alloc_decrement(struct xfs_btree_cur *cur, int level, int *stat);
 106
 107 /*
 108  * Delete the record pointed to by cur.
 109  * The cursor refers to the place where the record was (could be inserted)
 110  * when the operation returns.
 111  */
 112 extern int xfs_alloc_delete(struct xfs_btree_cur *cur, int *stat);
 113
 114 /*
 115  * Get the data from the pointed-to record.
 116  */
 117 extern int xfs_alloc_get_rec(struct xfs_btree_cur *cur, xfs_agblock_t *bno,
 118                                 xfs_extlen_t *len, int *stat);
 119
 120 /*
 121  * Increment cursor by one record at the level.
 122  * For nonzero levels the leaf-ward information is untouched.
 123  */
 124 extern int xfs_alloc_increment(struct xfs_btree_cur *cur, int level, int *stat);
 125
 126 /*
 127  * Insert the current record at the point referenced by cur.
 128  * The cursor may be inconsistent on return if splits have been done.
 129  */
 130 extern int xfs_alloc_insert(struct xfs_btree_cur *cur, int *stat);
 131
 132 /*
 133  * Lookup the record equal to [bno, len] in the btree given by cur.
 134  */
 135 extern int xfs_alloc_lookup_eq(struct xfs_btree_cur *cur, xfs_agblock_t bno,
 136                                 xfs_extlen_t len, int *stat);
 137
 138 /*
 139  * Lookup the first record greater than or equal to [bno, len]
 140  * in the btree given by cur.
 141  */
 142 extern int xfs_alloc_lookup_ge(struct xfs_btree_cur *cur, xfs_agblock_t bno,
 143                                 xfs_extlen_t len, int *stat);
 144
 145 /*
 146  * Lookup the first record less than or equal to [bno, len]
 147  * in the btree given by cur.
 148  */
 149 extern int xfs_alloc_lookup_le(struct xfs_btree_cur *cur, xfs_agblock_t bno,
 150                                 xfs_extlen_t len, int *stat);
 151
 152 /*
 153  * Update the record referred to by cur, to the value given by [bno, len].
 154  * This either works (return 0) or gets an EFSCORRUPTED error.
 155  */
 156 extern int xfs_alloc_update(struct xfs_btree_cur *cur, xfs_agblock_t bno,
 157                                 xfs_extlen_t len);
 158
 159 #endif  /* __XFS_ALLOC_BTREE_H__ */