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__ */
111
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