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
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,
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 */
67 typedef 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 */
77 typedef 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 */
87 typedef 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 */
99 typedef 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
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 */
xfs_dir2_data_entsize(int n)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 }
131
132 /*
133 * Pointer to an entry's tag word.
134 */
135 static inline __be16 *
xfs_dir2_data_entry_tag_p(xfs_dir2_data_entry_t * dep)136 xfs_dir2_data_entry_tag_p(xfs_dir2_data_entry_t *dep)
137 {
138 return (__be16 *)((char *)dep +
139 xfs_dir2_data_entsize(dep->namelen) - sizeof(__be16));
140 }
141
142 /*
143 * Pointer to a freespace's tag word.
144 */
145 static inline __be16 *
xfs_dir2_data_unused_tag_p(xfs_dir2_data_unused_t * dup)146 xfs_dir2_data_unused_tag_p(xfs_dir2_data_unused_t *dup)
147 {
148 return (__be16 *)((char *)dup +
149 be16_to_cpu(dup->length) - sizeof(__be16));
150 }
151
152 /*
153 * Function declarations.
154 */
155 #ifdef DEBUG
156 extern void xfs_dir2_data_check(struct xfs_inode *dp, struct xfs_dabuf *bp);
157 #else
158 #define xfs_dir2_data_check(dp,bp)
159 #endif
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,
165 int *loghead);
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,
169 xfs_dir2_data_entry_t *dep);
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,
175 xfs_dir2_data_aoff_t offset,
176 xfs_dir2_data_aoff_t len, int *needlogp,
177 int *needscanp);
178 extern void xfs_dir2_data_use_free(struct xfs_trans *tp, struct xfs_dabuf *bp,
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__ */
185