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_DIR2_DATA_H__
19#define	__XFS_DIR2_DATA_H__
20
21/*
22 * Directory format 2, data block structures.
23 */
24
25struct xfs_dabuf;
26struct xfs_da_args;
27struct xfs_inode;
28struct 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,
41 * spaces separated by 32gb.
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)	\
47	XFS_DIR2_BYTE_TO_DB(mp, XFS_DIR2_DATA_OFFSET)
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	\
55	(XFS_DIR2_DATA_DOT_OFFSET + XFS_DIR2_DATA_ENTSIZE(1))
56#define	XFS_DIR2_DATA_FIRST_OFFSET		\
57	(XFS_DIR2_DATA_DOTDOT_OFFSET + XFS_DIR2_DATA_ENTSIZE(2))
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 */
67typedef struct xfs_dir2_data_free {
68	__be16			offset;		/* start of freespace */
69	__be16			length;		/* length of freespace */
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 */
77typedef struct xfs_dir2_data_hdr {
78	__be32			magic;		/* XFS_DIR2_DATA_MAGIC */
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 */
87typedef struct xfs_dir2_data_entry {
88	__be64			inumber;	/* inode number */
89	__u8			namelen;	/* name length */
90	__u8			name[1];	/* name bytes, no null */
91						/* variable offset */
92	__be16			tag;		/* starting offset of us */
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 */
99typedef struct xfs_dir2_data_unused {
100	__be16			freetag;	/* XFS_DIR2_DATA_FREE_TAG */
101	__be16			length;		/* total free length */
102						/* variable offset */
103	__be16			tag;		/* starting offset of us */
104} xfs_dir2_data_unused_t;
105
106typedef 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 */
114typedef 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 */
126#define XFS_DIR2_DATA_ENTSIZE(n)	xfs_dir2_data_entsize(n)
127static inline int xfs_dir2_data_entsize(int n)
128{
129	return (int)roundup(offsetof(xfs_dir2_data_entry_t, name[0]) + (n) + \
130		 (uint)sizeof(xfs_dir2_data_off_t), XFS_DIR2_DATA_ALIGN);
131}
132
133/*
134 * Pointer to an entry's tag word.
135 */
136#define	XFS_DIR2_DATA_ENTRY_TAG_P(dep)	xfs_dir2_data_entry_tag_p(dep)
137static inline __be16 *
138xfs_dir2_data_entry_tag_p(xfs_dir2_data_entry_t *dep)
139{
140	return (__be16 *)((char *)dep +
141		XFS_DIR2_DATA_ENTSIZE(dep->namelen) - sizeof(__be16));
142}
143
144/*
145 * Pointer to a freespace's tag word.
146 */
147#define	XFS_DIR2_DATA_UNUSED_TAG_P(dup) \
148	xfs_dir2_data_unused_tag_p(dup)
149static inline __be16 *
150xfs_dir2_data_unused_tag_p(xfs_dir2_data_unused_t *dup)
151{
152	return (__be16 *)((char *)dup +
153			be16_to_cpu(dup->length) - sizeof(__be16));
154}
155
156/*
157 * Function declarations.
158 */
159#ifdef DEBUG
160extern void xfs_dir2_data_check(struct xfs_inode *dp, struct xfs_dabuf *bp);
161#else
162#define	xfs_dir2_data_check(dp,bp)
163#endif
164extern xfs_dir2_data_free_t *xfs_dir2_data_freefind(xfs_dir2_data_t *d,
165				xfs_dir2_data_unused_t *dup);
166extern xfs_dir2_data_free_t *xfs_dir2_data_freeinsert(xfs_dir2_data_t *d,
167				xfs_dir2_data_unused_t *dup, int *loghead);
168extern void xfs_dir2_data_freescan(struct xfs_mount *mp, xfs_dir2_data_t *d,
169				int *loghead);
170extern int xfs_dir2_data_init(struct xfs_da_args *args, xfs_dir2_db_t blkno,
171				struct xfs_dabuf **bpp);
172extern void xfs_dir2_data_log_entry(struct xfs_trans *tp, struct xfs_dabuf *bp,
173				xfs_dir2_data_entry_t *dep);
174extern void xfs_dir2_data_log_header(struct xfs_trans *tp,
175				struct xfs_dabuf *bp);
176extern void xfs_dir2_data_log_unused(struct xfs_trans *tp, struct xfs_dabuf *bp,
177				xfs_dir2_data_unused_t *dup);
178extern void xfs_dir2_data_make_free(struct xfs_trans *tp, struct xfs_dabuf *bp,
179				xfs_dir2_data_aoff_t offset,
180				xfs_dir2_data_aoff_t len, int *needlogp,
181				int *needscanp);
182extern void xfs_dir2_data_use_free(struct xfs_trans *tp, struct xfs_dabuf *bp,
183			       xfs_dir2_data_unused_t *dup,
184			       xfs_dir2_data_aoff_t offset,
185			       xfs_dir2_data_aoff_t len, int *needlogp,
186			       int *needscanp);
187
188#endif	/* __XFS_DIR2_DATA_H__ */
189