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authorYuval Adam <_@yuv.al>2017-08-30 08:25:59 +0000
committerYuval Adam <_@yuv.al>2017-08-30 08:25:59 +0000
commit8e4bff4cab0ddac6060645b0715210484d02ff40 (patch)
tree3a5c3024371a04692a3a6d9974d001cdff8ebf84 /fs/xfs/xfs_alloc_btree.h
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+/*
+ * Copyright (c) 2000,2005 Silicon Graphics, Inc.
+ * All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#ifndef __XFS_ALLOC_BTREE_H__
+#define __XFS_ALLOC_BTREE_H__
+
+/*
+ * Freespace on-disk structures
+ */
+
+struct xfs_buf;
+struct xfs_btree_cur;
+struct xfs_mount;
+
+/*
+ * There are two on-disk btrees, one sorted by blockno and one sorted
+ * by blockcount and blockno. All blocks look the same to make the code
+ * simpler; if we have time later, we'll make the optimizations.
+ */
+#define XFS_ABTB_MAGIC 0x41425442 /* 'ABTB' for bno tree */
+#define XFS_ABTB_CRC_MAGIC 0x41423342 /* 'AB3B' */
+#define XFS_ABTC_MAGIC 0x41425443 /* 'ABTC' for cnt tree */
+#define XFS_ABTC_CRC_MAGIC 0x41423343 /* 'AB3C' */
+
+/*
+ * Data record/key structure
+ */
+typedef struct xfs_alloc_rec {
+ __be32 ar_startblock; /* starting block number */
+ __be32 ar_blockcount; /* count of free blocks */
+} xfs_alloc_rec_t, xfs_alloc_key_t;
+
+typedef struct xfs_alloc_rec_incore {
+ xfs_agblock_t ar_startblock; /* starting block number */
+ xfs_extlen_t ar_blockcount; /* count of free blocks */
+} xfs_alloc_rec_incore_t;
+
+/* btree pointer type */
+typedef __be32 xfs_alloc_ptr_t;
+
+/*
+ * Block numbers in the AG:
+ * SB is sector 0, AGF is sector 1, AGI is sector 2, AGFL is sector 3.
+ */
+#define XFS_BNO_BLOCK(mp) ((xfs_agblock_t)(XFS_AGFL_BLOCK(mp) + 1))
+#define XFS_CNT_BLOCK(mp) ((xfs_agblock_t)(XFS_BNO_BLOCK(mp) + 1))
+
+/*
+ * Btree block header size depends on a superblock flag.
+ */
+#define XFS_ALLOC_BLOCK_LEN(mp) \
+ (xfs_sb_version_hascrc(&((mp)->m_sb)) ? \
+ XFS_BTREE_SBLOCK_CRC_LEN : XFS_BTREE_SBLOCK_LEN)
+
+/*
+ * Record, key, and pointer address macros for btree blocks.
+ *
+ * (note that some of these may appear unused, but they are used in userspace)
+ */
+#define XFS_ALLOC_REC_ADDR(mp, block, index) \
+ ((xfs_alloc_rec_t *) \
+ ((char *)(block) + \
+ XFS_ALLOC_BLOCK_LEN(mp) + \
+ (((index) - 1) * sizeof(xfs_alloc_rec_t))))
+
+#define XFS_ALLOC_KEY_ADDR(mp, block, index) \
+ ((xfs_alloc_key_t *) \
+ ((char *)(block) + \
+ XFS_ALLOC_BLOCK_LEN(mp) + \
+ ((index) - 1) * sizeof(xfs_alloc_key_t)))
+
+#define XFS_ALLOC_PTR_ADDR(mp, block, index, maxrecs) \
+ ((xfs_alloc_ptr_t *) \
+ ((char *)(block) + \
+ XFS_ALLOC_BLOCK_LEN(mp) + \
+ (maxrecs) * sizeof(xfs_alloc_key_t) + \
+ ((index) - 1) * sizeof(xfs_alloc_ptr_t)))
+
+extern struct xfs_btree_cur *xfs_allocbt_init_cursor(struct xfs_mount *,
+ struct xfs_trans *, struct xfs_buf *,
+ xfs_agnumber_t, xfs_btnum_t);
+extern int xfs_allocbt_maxrecs(struct xfs_mount *, int, int);
+
+extern const struct xfs_buf_ops xfs_allocbt_buf_ops;
+
+#endif /* __XFS_ALLOC_BTREE_H__ */