[linux-2.6-block.git] / fs / xfs / xfs_dir2_data.h

/*
 * 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__ */
Commit	Line	Data
1da177e4	1	/*
7b718769 NS	2	* Copyright (c) 2000,2005 Silicon Graphics, Inc.
7b718769 NS	3	* All Rights Reserved.
1da177e4	4	*
7b718769 NS	5	* This program is free software; you can redistribute it and/or
7b718769 NS	6	* modify it under the terms of the GNU General Public License as
1da177e4 LT	7	* published by the Free Software Foundation.
1da177e4 LT	8	*
7b718769 NS	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.
1da177e4	13	*
7b718769 NS	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
1da177e4 LT	17	*/
	18	#ifndef __XFS_DIR2_DATA_H__
	19	#define __XFS_DIR2_DATA_H__
	20
	21	/*
	22	* Directory format 2, data block structures.
	23	*/
	24
	25	struct xfs_dabuf;
	26	struct xfs_da_args;
	27	struct xfs_inode;
	28	struct xfs_trans;
	29
	30	/*
	31	* Constants.
	32	*/
	33	#define XFS_DIR2_DATA_MAGIC 0x58443244 /* XD2D: for multiblock dirs */
	34	#define XFS_DIR2_DATA_ALIGN_LOG 3 /* i.e., 8 bytes */
	35	#define XFS_DIR2_DATA_ALIGN (1 << XFS_DIR2_DATA_ALIGN_LOG)
	36	#define XFS_DIR2_DATA_FREE_TAG 0xffff
	37	#define XFS_DIR2_DATA_FD_COUNT 3
	38
	39	/*
	40	* Directory address space divided into sections,
9da096fd	41	* spaces separated by 32GB.
1da177e4 LT	42	*/
	43	#define XFS_DIR2_SPACE_SIZE (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
	44	#define XFS_DIR2_DATA_SPACE 0
	45	#define XFS_DIR2_DATA_OFFSET (XFS_DIR2_DATA_SPACE * XFS_DIR2_SPACE_SIZE)
	46	#define XFS_DIR2_DATA_FIRSTDB(mp) \
bbaaf538	47	xfs_dir2_byte_to_db(mp, XFS_DIR2_DATA_OFFSET)
1da177e4 LT	48
	49	/*
	50	* Offsets of . and .. in data space (always block 0)
	51	*/
	52	#define XFS_DIR2_DATA_DOT_OFFSET \
	53	((xfs_dir2_data_aoff_t)sizeof(xfs_dir2_data_hdr_t))
	54	#define XFS_DIR2_DATA_DOTDOT_OFFSET \
bbaaf538	55	(XFS_DIR2_DATA_DOT_OFFSET + xfs_dir2_data_entsize(1))
1da177e4	56	#define XFS_DIR2_DATA_FIRST_OFFSET \
bbaaf538	57	(XFS_DIR2_DATA_DOTDOT_OFFSET + xfs_dir2_data_entsize(2))
1da177e4 LT	58
	59	/*
	60	* Structures.
	61	*/
	62
	63	/*
	64	* Describe a free area in the data block.
	65	* The freespace will be formatted as a xfs_dir2_data_unused_t.
	66	*/
	67	typedef struct xfs_dir2_data_free {
70e73f59 NS	68	__be16 offset; /* start of freespace */
70e73f59 NS	69	__be16 length; /* length of freespace */
1da177e4 LT	70	} xfs_dir2_data_free_t;
	71
	72	/*
	73	* Header for the data blocks.
	74	* Always at the beginning of a directory-sized block.
	75	* The code knows that XFS_DIR2_DATA_FD_COUNT is 3.
	76	*/
	77	typedef struct xfs_dir2_data_hdr {
70e73f59	78	__be32 magic; /* XFS_DIR2_DATA_MAGIC */
1da177e4 LT	79	/* or XFS_DIR2_BLOCK_MAGIC */
	80	xfs_dir2_data_free_t bestfree[XFS_DIR2_DATA_FD_COUNT];
	81	} xfs_dir2_data_hdr_t;
	82
	83	/*
	84	* Active entry in a data block. Aligned to 8 bytes.
	85	* Tag appears as the last 2 bytes.
	86	*/
	87	typedef struct xfs_dir2_data_entry {
ff9901c1 CH	88	__be64 inumber; /* inode number */
	89	__u8 namelen; /* name length */
	90	__u8 name[1]; /* name bytes, no null */
1da177e4	91	/* variable offset */
ff9901c1	92	__be16 tag; /* starting offset of us */
1da177e4 LT	93	} xfs_dir2_data_entry_t;
	94
	95	/*
	96	* Unused entry in a data block. Aligned to 8 bytes.
	97	* Tag appears as the last 2 bytes.
	98	*/
	99	typedef struct xfs_dir2_data_unused {
ad354eb3 NS	100	__be16 freetag; /* XFS_DIR2_DATA_FREE_TAG */
ad354eb3 NS	101	__be16 length; /* total free length */
1da177e4	102	/* variable offset */
ad354eb3	103	__be16 tag; /* starting offset of us */
1da177e4 LT	104	} xfs_dir2_data_unused_t;
	105
	106	typedef union {
	107	xfs_dir2_data_entry_t entry;
	108	xfs_dir2_data_unused_t unused;
	109	} xfs_dir2_data_union_t;
	110
	111	/*
	112	* Generic data block structure, for xfs_db.
	113	*/
	114	typedef struct xfs_dir2_data {
	115	xfs_dir2_data_hdr_t hdr; /* magic XFS_DIR2_DATA_MAGIC */
	116	xfs_dir2_data_union_t u[1];
	117	} xfs_dir2_data_t;
	118
	119	/*
	120	* Macros.
	121	*/
	122
	123	/*
	124	* Size of a data entry.
	125	*/
a844f451 NS	126	static inline int xfs_dir2_data_entsize(int n)
	127	{
	128	return (int)roundup(offsetof(xfs_dir2_data_entry_t, name[0]) + (n) + \
	129	(uint)sizeof(xfs_dir2_data_off_t), XFS_DIR2_DATA_ALIGN);
	130	}
1da177e4 LT	131
	132	/*
	133	* Pointer to an entry's tag word.
	134	*/
3d693c6e	135	static inline __be16 *
a844f451 NS	136	xfs_dir2_data_entry_tag_p(xfs_dir2_data_entry_t *dep)
a844f451 NS	137	{
3d693c6e	138	return (__be16 )((char )dep +
bbaaf538	139	xfs_dir2_data_entsize(dep->namelen) - sizeof(__be16));
a844f451	140	}
1da177e4 LT	141
	142	/*
	143	* Pointer to a freespace's tag word.
	144	*/
1fba9f7f	145	static inline __be16 *
a844f451 NS	146	xfs_dir2_data_unused_tag_p(xfs_dir2_data_unused_t *dup)
a844f451 NS	147	{
1fba9f7f NS	148	return (__be16 )((char )dup +
1fba9f7f NS	149	be16_to_cpu(dup->length) - sizeof(__be16));
a844f451	150	}
1da177e4 LT	151
	152	/*
	153	* Function declarations.
	154	*/
1da177e4	155	#ifdef DEBUG
a844f451	156	extern void xfs_dir2_data_check(struct xfs_inode dp, struct xfs_dabuf bp);
1da177e4 LT	157	#else
	158	#define xfs_dir2_data_check(dp,bp)
	159	#endif
a844f451 NS	160	extern xfs_dir2_data_free_t xfs_dir2_data_freefind(xfs_dir2_data_t d,
	161	xfs_dir2_data_unused_t *dup);
	162	extern xfs_dir2_data_free_t xfs_dir2_data_freeinsert(xfs_dir2_data_t d,
	163	xfs_dir2_data_unused_t dup, int loghead);
	164	extern void xfs_dir2_data_freescan(struct xfs_mount mp, xfs_dir2_data_t d,
ef497f8a	165	int *loghead);
a844f451 NS	166	extern int xfs_dir2_data_init(struct xfs_da_args *args, xfs_dir2_db_t blkno,
	167	struct xfs_dabuf **bpp);
	168	extern void xfs_dir2_data_log_entry(struct xfs_trans tp, struct xfs_dabuf bp,
1da177e4	169	xfs_dir2_data_entry_t *dep);
a844f451 NS	170	extern void xfs_dir2_data_log_header(struct xfs_trans *tp,
	171	struct xfs_dabuf *bp);
	172	extern void xfs_dir2_data_log_unused(struct xfs_trans tp, struct xfs_dabuf bp,
	173	xfs_dir2_data_unused_t *dup);
	174	extern void xfs_dir2_data_make_free(struct xfs_trans tp, struct xfs_dabuf bp,
1da177e4 LT	175	xfs_dir2_data_aoff_t offset,
	176	xfs_dir2_data_aoff_t len, int *needlogp,
	177	int *needscanp);
a844f451	178	extern void xfs_dir2_data_use_free(struct xfs_trans tp, struct xfs_dabuf bp,
1da177e4 LT	179	xfs_dir2_data_unused_t *dup,
	180	xfs_dir2_data_aoff_t offset,
	181	xfs_dir2_data_aoff_t len, int *needlogp,
	182	int *needscanp);
	183
	184	#endif /* __XFS_DIR2_DATA_H__ */