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xfs_dir2_data.h
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xfs_dir2_data.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_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__ */