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root/fs/xfs/xfs_dir2_data.h

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INCLUDED FROM


DEFINITIONS

This source file includes following definitions.
  1. xfs_dir2_data_entsize
  2. xfs_dir2_data_entry_tag_p
  3. xfs_dir2_data_unused_tag_p

/*
 * 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_DIR2_DATA_H__
#define __XFS_DIR2_DATA_H__

/*
 * Directory format 2, data block structures.
 */

struct xfs_dabuf;
struct xfs_da_args;
struct xfs_inode;
struct xfs_trans;

/*
 * Constants.
 */
#define XFS_DIR2_DATA_MAGIC     0x58443244      /* XD2D: for multiblock dirs */
#define XFS_DIR2_DATA_ALIGN_LOG 3               /* i.e., 8 bytes */
#define XFS_DIR2_DATA_ALIGN     (1 << XFS_DIR2_DATA_ALIGN_LOG)
#define XFS_DIR2_DATA_FREE_TAG  0xffff
#define XFS_DIR2_DATA_FD_COUNT  3

/*
 * Directory address space divided into sections,
 * spaces separated by 32gb.
 */
#define XFS_DIR2_SPACE_SIZE     (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
#define XFS_DIR2_DATA_SPACE     0
#define XFS_DIR2_DATA_OFFSET    (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE)
#define XFS_DIR2_DATA_FIRSTDB(mp)       \
        xfs_dir2_byte_to_db(mp, XFS_DIR2_DATA_OFFSET)

/*
 * Offsets of . and .. in data space (always block 0)
 */
#define XFS_DIR2_DATA_DOT_OFFSET        \
        ((xfs_dir2_data_aoff_t)sizeof(xfs_dir2_data_hdr_t))
#define XFS_DIR2_DATA_DOTDOT_OFFSET     \
        (XFS_DIR2_DATA_DOT_OFFSET + xfs_dir2_data_entsize(1))
#define XFS_DIR2_DATA_FIRST_OFFSET              \
        (XFS_DIR2_DATA_DOTDOT_OFFSET + xfs_dir2_data_entsize(2))

/*
 * Structures.
 */

/*
 * Describe a free area in the data block.
 * The freespace will be formatted as a xfs_dir2_data_unused_t.
 */
typedef struct xfs_dir2_data_free {
        __be16                  offset;         /* start of freespace */
        __be16                  length;         /* length of freespace */
} xfs_dir2_data_free_t;

/*
 * Header for the data blocks.
 * Always at the beginning of a directory-sized block.
 * The code knows that XFS_DIR2_DATA_FD_COUNT is 3.
 */
typedef struct xfs_dir2_data_hdr {
        __be32                  magic;          /* XFS_DIR2_DATA_MAGIC */
                                                /* or XFS_DIR2_BLOCK_MAGIC */
        xfs_dir2_data_free_t    bestfree[XFS_DIR2_DATA_FD_COUNT];
} xfs_dir2_data_hdr_t;

/*
 * Active entry in a data block.  Aligned to 8 bytes.
 * Tag appears as the last 2 bytes.
 */
typedef struct xfs_dir2_data_entry {
        __be64                  inumber;        /* inode number */
        __u8                    namelen;        /* name length */
        __u8                    name[1];        /* name bytes, no null */
                                                /* variable offset */
        __be16                  tag;            /* starting offset of us */
} xfs_dir2_data_entry_t;

/*
 * Unused entry in a data block.  Aligned to 8 bytes.
 * Tag appears as the last 2 bytes.
 */
typedef struct xfs_dir2_data_unused {
        __be16                  freetag;        /* XFS_DIR2_DATA_FREE_TAG */
        __be16                  length;         /* total free length */
                                                /* variable offset */
        __be16                  tag;            /* starting offset of us */
} xfs_dir2_data_unused_t;

typedef union {
        xfs_dir2_data_entry_t   entry;
        xfs_dir2_data_unused_t  unused;
} xfs_dir2_data_union_t;

/*
 * Generic data block structure, for xfs_db.
 */
typedef struct xfs_dir2_data {
        xfs_dir2_data_hdr_t     hdr;            /* magic XFS_DIR2_DATA_MAGIC */
        xfs_dir2_data_union_t   u[1];
} xfs_dir2_data_t;

/*
 * Macros.
 */

/*
 * Size of a data entry.
 */
static inline int xfs_dir2_data_entsize(int n)
{
        return (int)roundup(offsetof(xfs_dir2_data_entry_t, name[0]) + (n) + \
                 (uint)sizeof(xfs_dir2_data_off_t), XFS_DIR2_DATA_ALIGN);
}

/*
 * Pointer to an entry's tag word.
 */
static inline __be16 *
xfs_dir2_data_entry_tag_p(xfs_dir2_data_entry_t *dep)
{
        return (__be16 *)((char *)dep +
                xfs_dir2_data_entsize(dep->namelen) - sizeof(__be16));
}

/*
 * Pointer to a freespace's tag word.
 */
static inline __be16 *
xfs_dir2_data_unused_tag_p(xfs_dir2_data_unused_t *dup)
{
        return (__be16 *)((char *)dup +
                        be16_to_cpu(dup->length) - sizeof(__be16));
}

/*
 * Function declarations.
 */
#ifdef DEBUG
extern void xfs_dir2_data_check(struct xfs_inode *dp, struct xfs_dabuf *bp);
#else
#define xfs_dir2_data_check(dp,bp)
#endif
extern xfs_dir2_data_free_t *xfs_dir2_data_freefind(xfs_dir2_data_t *d,
                                xfs_dir2_data_unused_t *dup);
extern xfs_dir2_data_free_t *xfs_dir2_data_freeinsert(xfs_dir2_data_t *d,
                                xfs_dir2_data_unused_t *dup, int *loghead);
extern void xfs_dir2_data_freescan(struct xfs_mount *mp, xfs_dir2_data_t *d,
                                int *loghead);
extern int xfs_dir2_data_init(struct xfs_da_args *args, xfs_dir2_db_t blkno,
                                struct xfs_dabuf **bpp);
extern void xfs_dir2_data_log_entry(struct xfs_trans *tp, struct xfs_dabuf *bp,
                                xfs_dir2_data_entry_t *dep);
extern void xfs_dir2_data_log_header(struct xfs_trans *tp,
                                struct xfs_dabuf *bp);
extern void xfs_dir2_data_log_unused(struct xfs_trans *tp, struct xfs_dabuf *bp,
                                xfs_dir2_data_unused_t *dup);
extern void xfs_dir2_data_make_free(struct xfs_trans *tp, struct xfs_dabuf *bp,
                                xfs_dir2_data_aoff_t offset,
                                xfs_dir2_data_aoff_t len, int *needlogp,
                                int *needscanp);
extern void xfs_dir2_data_use_free(struct xfs_trans *tp, struct xfs_dabuf *bp,
                               xfs_dir2_data_unused_t *dup,
                               xfs_dir2_data_aoff_t offset,
                               xfs_dir2_data_aoff_t len, int *needlogp,
                               int *needscanp);

#endif  /* __XFS_DIR2_DATA_H__ */

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