ext2_io.h revision 4690e621acd4579dae60b6f55f58284ee805e86d 
1/*
2 * io.h --- the I/O manager abstraction
3 *
4 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
5 *
6 * %Begin-Header%
7 * This file may be redistributed under the terms of the GNU Public
8 * License.
9 * %End-Header%
10 */
11
12#ifndef _EXT2FS_EXT2_IO_H
13#define _EXT2FS_EXT2_IO_H
14
15/*
16 * ext2_loff_t is defined here since unix_io.c needs it.
17 */
18#if defined(__GNUC__) || defined(HAS_LONG_LONG)
19typedef long long	ext2_loff_t;
20#else
21typedef long		ext2_loff_t;
22#endif
23
24/* llseek.c */
25ext2_loff_t ext2fs_llseek (int, ext2_loff_t, int);
26
27typedef struct struct_io_manager *io_manager;
28typedef struct struct_io_channel *io_channel;
29typedef struct struct_io_stats *io_stats;
30
31#define CHANNEL_FLAGS_WRITETHROUGH	0x01
32
33struct struct_io_channel {
34	errcode_t	magic;
35	io_manager	manager;
36	char		*name;
37	int		block_size;
38	errcode_t	(*read_error)(io_channel channel,
39				      unsigned long block,
40				      int count,
41				      void *data,
42				      size_t size,
43				      int actual_bytes_read,
44				      errcode_t	error);
45	errcode_t	(*write_error)(io_channel channel,
46				       unsigned long block,
47				       int count,
48				       const void *data,
49				       size_t size,
50				       int actual_bytes_written,
51				       errcode_t error);
52	int		refcount;
53	int		flags;
54	long		reserved[14];
55	void		*private_data;
56	void		*app_data;
57};
58
59struct struct_io_stats {
60	int			num_fields;
61	int			reserved;
62	unsigned long long	bytes_read;
63	unsigned long long	bytes_written;
64};
65
66struct struct_io_manager {
67	errcode_t magic;
68	const char *name;
69	errcode_t (*open)(const char *name, int flags, io_channel *channel);
70	errcode_t (*close)(io_channel channel);
71	errcode_t (*set_blksize)(io_channel channel, int blksize);
72	errcode_t (*read_blk)(io_channel channel, unsigned long block,
73			      int count, void *data);
74	errcode_t (*write_blk)(io_channel channel, unsigned long block,
75			       int count, const void *data);
76	errcode_t (*flush)(io_channel channel);
77	errcode_t (*write_byte)(io_channel channel, unsigned long offset,
78				int count, const void *data);
79	errcode_t (*set_option)(io_channel channel, const char *option,
80				const char *arg);
81	errcode_t (*get_stats)(io_channel channel, io_stats *io_stats);
82	errcode_t (*read_blk64)(io_channel channel, unsigned long long block,
83					int count, void *data);
84	errcode_t (*write_blk64)(io_channel channel, unsigned long long block,
85					int count, const void *data);
86	long	reserved[16];
87};
88
89#define IO_FLAG_RW		0x0001
90#define IO_FLAG_EXCLUSIVE	0x0002
91
92/*
93 * Convenience functions....
94 */
95#define io_channel_close(c) 		((c)->manager->close((c)))
96#define io_channel_set_blksize(c,s)	((c)->manager->set_blksize((c),s))
97#define io_channel_read_blk(c,b,n,d)	((c)->manager->read_blk((c),b,n,d))
98#define io_channel_write_blk(c,b,n,d)	((c)->manager->write_blk((c),b,n,d))
99#define io_channel_flush(c) 		((c)->manager->flush((c)))
100#define io_channel_bumpcount(c)		((c)->refcount++)
101
102/* io_manager.c */
103extern errcode_t io_channel_set_options(io_channel channel,
104					const char *options);
105extern errcode_t io_channel_write_byte(io_channel channel,
106				       unsigned long offset,
107				       int count, const void *data);
108extern errcode_t io_channel_read_blk64(io_channel channel,
109				       unsigned long long block,
110				       int count, void *data);
111extern errcode_t io_channel_write_blk64(io_channel channel,
112					unsigned long long block,
113					int count, const void *data);
114
115/* unix_io.c */
116extern io_manager unix_io_manager;
117
118/* undo_io.c */
119extern io_manager undo_io_manager;
120extern errcode_t set_undo_io_backing_manager(io_manager manager);
121extern errcode_t set_undo_io_backup_file(char *file_name);
122
123/* test_io.c */
124extern io_manager test_io_manager, test_io_backing_manager;
125extern void (*test_io_cb_read_blk)
126	(unsigned long block, int count, errcode_t err);
127extern void (*test_io_cb_write_blk)
128	(unsigned long block, int count, errcode_t err);
129extern void (*test_io_cb_set_blksize)
130	(int blksize, errcode_t err);
131
132#endif /* _EXT2FS_EXT2_IO_H */
133
134