summaryrefslogtreecommitdiff
path: root/e2fsprogs/ext2fs/kernel-jbd.h
blob: 56914ea47bc1b4c2c353c24e5c35aad57d63c57c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
/*
 * linux/include/linux/jbd.h
 *
 * Written by Stephen C. Tweedie <sct@redhat.com>
 *
 * Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
 *
 * This file is part of the Linux kernel and is made available under
 * the terms of the GNU General Public License, version 2, or at your
 * option, any later version, incorporated herein by reference.
 *
 * Definitions for transaction data structures for the buffer cache
 * filesystem journaling support.
 */

#ifndef _LINUX_JBD_H
#define _LINUX_JBD_H

#include <sys/types.h>
#include <linux/types.h>
#include "ext2fs/ext2fs.h"

/*
 * Standard header for all descriptor blocks:
 */

typedef struct journal_header_s
{
	__u32		h_magic;
	__u32		h_blocktype;
	__u32		h_sequence;
} journal_header_t;

/*
 * This is the global e2fsck structure.
 */
typedef struct e2fsck_struct *e2fsck_t;


struct inode {
	e2fsck_t        i_ctx;
	ext2_ino_t      i_ino;
	struct ext2_inode i_ext2;
};


/*
 * The journal superblock.  All fields are in big-endian byte order.
 */
typedef struct journal_superblock_s
{
/* 0x0000 */
	journal_header_t s_header;

/* 0x000C */
	/* Static information describing the journal */
	__u32	s_blocksize;		/* journal device blocksize */
	__u32	s_maxlen;		/* total blocks in journal file */
	__u32	s_first;		/* first block of log information */

/* 0x0018 */
	/* Dynamic information describing the current state of the log */
	__u32	s_sequence;		/* first commit ID expected in log */
	__u32	s_start;		/* blocknr of start of log */

/* 0x0020 */
	/* Error value, as set by journal_abort(). */
	__s32	s_errno;

/* 0x0024 */
	/* Remaining fields are only valid in a version-2 superblock */
	__u32	s_feature_compat;	/* compatible feature set */
	__u32	s_feature_incompat;	/* incompatible feature set */
	__u32	s_feature_ro_compat;	/* readonly-compatible feature set */
/* 0x0030 */
	__u8	s_uuid[16];		/* 128-bit uuid for journal */

/* 0x0040 */
	__u32	s_nr_users;		/* Nr of filesystems sharing log */

	__u32	s_dynsuper;		/* Blocknr of dynamic superblock copy*/

/* 0x0048 */
	__u32	s_max_transaction;	/* Limit of journal blocks per trans.*/
	__u32	s_max_trans_data;	/* Limit of data blocks per trans. */

/* 0x0050 */
	__u32	s_padding[44];

/* 0x0100 */
	__u8	s_users[16*48];		/* ids of all fs'es sharing the log */
/* 0x0400 */
} journal_superblock_t;


extern int journal_blocks_per_page(struct inode *inode);
extern int jbd_blocks_per_page(struct inode *inode);

#define JFS_MIN_JOURNAL_BLOCKS 1024


/*
 * Internal structures used by the logging mechanism:
 */

#define JFS_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */

/*
 * Descriptor block types:
 */

#define JFS_DESCRIPTOR_BLOCK	1
#define JFS_COMMIT_BLOCK	2
#define JFS_SUPERBLOCK_V1	3
#define JFS_SUPERBLOCK_V2	4
#define JFS_REVOKE_BLOCK	5

/*
 * The block tag: used to describe a single buffer in the journal
 */
typedef struct journal_block_tag_s
{
	__u32		t_blocknr;	/* The on-disk block number */
	__u32		t_flags;	/* See below */
} journal_block_tag_t;

/*
 * The revoke descriptor: used on disk to describe a series of blocks to
 * be revoked from the log
 */
typedef struct journal_revoke_header_s
{
	journal_header_t r_header;
	int		 r_count;	/* Count of bytes used in the block */
} journal_revoke_header_t;


/* Definitions for the journal tag flags word: */
#define JFS_FLAG_ESCAPE		1	/* on-disk block is escaped */
#define JFS_FLAG_SAME_UUID	2	/* block has same uuid as previous */
#define JFS_FLAG_DELETED	4	/* block deleted by this transaction */
#define JFS_FLAG_LAST_TAG	8	/* last tag in this descriptor block */




#define JFS_HAS_COMPAT_FEATURE(j,mask)					\
	((j)->j_format_version >= 2 &&					\
	 ((j)->j_superblock->s_feature_compat & cpu_to_be32((mask))))
#define JFS_HAS_RO_COMPAT_FEATURE(j,mask)				\
	((j)->j_format_version >= 2 &&					\
	 ((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask))))
#define JFS_HAS_INCOMPAT_FEATURE(j,mask)				\
	((j)->j_format_version >= 2 &&					\
	 ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))

#define JFS_FEATURE_INCOMPAT_REVOKE	0x00000001

/* Features known to this kernel version: */
#define JFS_KNOWN_COMPAT_FEATURES	0
#define JFS_KNOWN_ROCOMPAT_FEATURES	0
#define JFS_KNOWN_INCOMPAT_FEATURES	JFS_FEATURE_INCOMPAT_REVOKE

/* Comparison functions for transaction IDs: perform comparisons using
 * modulo arithmetic so that they work over sequence number wraps. */


/*
 * Definitions which augment the buffer_head layer
 */

/* journaling buffer types */
#define BJ_None		0	/* Not journaled */
#define BJ_SyncData	1	/* Normal data: flush before commit */
#define BJ_AsyncData	2	/* writepage data: wait on it before commit */
#define BJ_Metadata	3	/* Normal journaled metadata */
#define BJ_Forget	4	/* Buffer superceded by this transaction */
#define BJ_IO		5	/* Buffer is for temporary IO use */
#define BJ_Shadow	6	/* Buffer contents being shadowed to the log */
#define BJ_LogCtl	7	/* Buffer contains log descriptors */
#define BJ_Reserved	8	/* Buffer is reserved for access by journal */
#define BJ_Types	9


struct kdev_s {
	e2fsck_t        k_ctx;
	int             k_dev;
};

typedef struct kdev_s *kdev_t;
typedef unsigned int tid_t;

struct journal_s
{
	unsigned long		j_flags;
	int			j_errno;
	struct buffer_head *	j_sb_buffer;
	struct journal_superblock_s *j_superblock;
	int			j_format_version;
	unsigned long		j_head;
	unsigned long		j_tail;
	unsigned long		j_free;
	unsigned long		j_first, j_last;
	kdev_t			j_dev;
	kdev_t			j_fs_dev;
	int			j_blocksize;
	unsigned int		j_blk_offset;
	unsigned int		j_maxlen;
	struct inode *		j_inode;
	tid_t			j_tail_sequence;
	tid_t			j_transaction_sequence;
	__u8			j_uuid[16];
	struct jbd_revoke_table_s *j_revoke;
};

typedef struct journal_s journal_t;

extern int	   journal_recover    (journal_t *journal);
extern int	   journal_skip_recovery (journal_t *);

/* Primary revoke support */
extern int	   journal_init_revoke(journal_t *, int);
extern void	   journal_destroy_revoke_caches(void);
extern int	   journal_init_revoke_caches(void);

/* Recovery revoke support */
extern int	   journal_set_revoke(journal_t *, unsigned long, tid_t);
extern int	   journal_test_revoke(journal_t *, unsigned long, tid_t);
extern void	   journal_clear_revoke(journal_t *);
extern void	   journal_brelse_array(struct buffer_head *b[], int n);

extern void	   journal_destroy_revoke(journal_t *);


#endif	/* _LINUX_JBD_H */