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 {
  43         xfs_agblock_t   ar_startblock;  /* starting block number */
  44         xfs_extlen_t    ar_blockcount;  /* count of free blocks */
  45 } xfs_alloc_rec_t, xfs_alloc_key_t;
  46
  47 typedef xfs_agblock_t xfs_alloc_ptr_t;  /* btree pointer type */
  48                                         /* btree block header type */
  49 typedef struct xfs_btree_sblock xfs_alloc_block_t;
  50
  51 #define XFS_BUF_TO_ALLOC_BLOCK(bp)      ((xfs_alloc_block_t *)XFS_BUF_PTR(bp))
  52
  53 /*
  54  * Real block structures have a size equal to the disk block size.
  55  */
  56 #define XFS_ALLOC_BLOCK_SIZE(lev,cur)   (1 << (cur)->bc_blocklog)
  57 #define XFS_ALLOC_BLOCK_MAXRECS(lev,cur) ((cur)->bc_mp->m_alloc_mxr[lev != 0])
  58 #define XFS_ALLOC_BLOCK_MINRECS(lev,cur) ((cur)->bc_mp->m_alloc_mnr[lev != 0])
  59
  60 /*
  61  * Minimum and maximum blocksize and sectorsize.
  62  * The blocksize upper limit is pretty much arbitrary.
  63  * The sectorsize upper limit is due to sizeof(sb_sectsize).
  64  */
  65 #define XFS_MIN_BLOCKSIZE_LOG   9       /* i.e. 512 bytes */
  66 #define XFS_MAX_BLOCKSIZE_LOG   16      /* i.e. 65536 bytes */
  67 #define XFS_MIN_BLOCKSIZE       (1 << XFS_MIN_BLOCKSIZE_LOG)
  68 #define XFS_MAX_BLOCKSIZE       (1 << XFS_MAX_BLOCKSIZE_LOG)
  69 #define XFS_MIN_SECTORSIZE_LOG  9       /* i.e. 512 bytes */
  70 #define XFS_MAX_SECTORSIZE_LOG  15      /* i.e. 32768 bytes */
  71 #define XFS_MIN_SECTORSIZE      (1 << XFS_MIN_SECTORSIZE_LOG)
  72 #define XFS_MAX_SECTORSIZE      (1 << XFS_MAX_SECTORSIZE_LOG)
  73
  74 /*
  75  * Block numbers in the AG:
  76  * SB is sector 0, AGF is sector 1, AGI is sector 2, AGFL is sector 3.
  77  */
  78 #define XFS_BNO_BLOCK(mp)       ((xfs_agblock_t)(XFS_AGFL_BLOCK(mp) + 1))
  79 #define XFS_CNT_BLOCK(mp)       ((xfs_agblock_t)(XFS_BNO_BLOCK(mp) + 1))
  80
  81 /*
  82  * Record, key, and pointer address macros for btree blocks.
  83  */
  84 #define XFS_ALLOC_REC_ADDR(bb,i,cur)    \
  85         XFS_BTREE_REC_ADDR(XFS_ALLOC_BLOCK_SIZE(0,cur), xfs_alloc, \
  86                                 bb, i, XFS_ALLOC_BLOCK_MAXRECS(0, cur))
  87
  88 #define XFS_ALLOC_KEY_ADDR(bb,i,cur)    \
  89         XFS_BTREE_KEY_ADDR(XFS_ALLOC_BLOCK_SIZE(1,cur), xfs_alloc, \
  90                                 bb, i, XFS_ALLOC_BLOCK_MAXRECS(1, cur))
  91
  92 #define XFS_ALLOC_PTR_ADDR(bb,i,cur)    \
  93         XFS_BTREE_PTR_ADDR(XFS_ALLOC_BLOCK_SIZE(1,cur), xfs_alloc, \
  94                                 bb, i, XFS_ALLOC_BLOCK_MAXRECS(1, cur))
  95
  96 /*
  97  * Decrement cursor by one record at the level.
  98  * For nonzero levels the leaf-ward information is untouched.
  99  */
 100 extern int xfs_alloc_decrement(struct xfs_btree_cur *cur, int level, int *stat);
 101
 102 /*
 103  * Delete the record pointed to by cur.
 104  * The cursor refers to the place where the record was (could be inserted)
 105  * when the operation returns.
 106  */
 107 extern int xfs_alloc_delete(struct xfs_btree_cur *cur, int *stat);
 108
 109 /*
 110  * Get the data from the pointed-to record.
 111  */
 112 extern int xfs_alloc_get_rec(struct xfs_btree_cur *cur, xfs_agblock_t *bno,
 113                                 xfs_extlen_t *len, int *stat);
 114
 115 /*
 116  * Increment cursor by one record at the level.
 117  * For nonzero levels the leaf-ward information is untouched.
 118  */
 119 extern int xfs_alloc_increment(struct xfs_btree_cur *cur, int level, int *stat);
 120
 121 /*
 122  * Insert the current record at the point referenced by cur.
 123  * The cursor may be inconsistent on return if splits have been done.
 124  */
 125 extern int xfs_alloc_insert(struct xfs_btree_cur *cur, int *stat);
 126
 127 /*
 128  * Lookup the record equal to [bno, len] in the btree given by cur.
 129  */
 130 extern int xfs_alloc_lookup_eq(struct xfs_btree_cur *cur, xfs_agblock_t bno,
 131                                 xfs_extlen_t len, int *stat);
 132
 133 /*
 134  * Lookup the first record greater than or equal to [bno, len]
 135  * in the btree given by cur.
 136  */
 137 extern int xfs_alloc_lookup_ge(struct xfs_btree_cur *cur, xfs_agblock_t bno,
 138                                 xfs_extlen_t len, int *stat);
 139
 140 /*
 141  * Lookup the first record less than or equal to [bno, len]
 142  * in the btree given by cur.
 143  */
 144 extern int xfs_alloc_lookup_le(struct xfs_btree_cur *cur, xfs_agblock_t bno,
 145                                 xfs_extlen_t len, int *stat);
 146
 147 /*
 148  * Update the record referred to by cur, to the value given by [bno, len].
 149  * This either works (return 0) or gets an EFSCORRUPTED error.
 150  */
 151 extern int xfs_alloc_update(struct xfs_btree_cur *cur, xfs_agblock_t bno,
 152                                 xfs_extlen_t len);
 153
 154 #endif  /* __XFS_ALLOC_BTREE_H__ */