ext2_io.h revision d866599ab4955858b1541f0891b1b165ba66493a 
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 Library
8 * General Public License, version 2.
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#define CHANNEL_FLAGS_DISCARD_ZEROES	0x02
33
34#define io_channel_discard_zeroes_data(i) (i->flags & CHANNEL_FLAGS_DISCARD_ZEROES)
35
36struct struct_io_channel {
37	errcode_t	magic;
38	io_manager	manager;
39	char		*name;
40	int		block_size;
41	errcode_t	(*read_error)(io_channel channel,
42				      unsigned long block,
43				      int count,
44				      void *data,
45				      size_t size,
46				      int actual_bytes_read,
47				      errcode_t	error);
48	errcode_t	(*write_error)(io_channel channel,
49				       unsigned long block,
50				       int count,
51				       const void *data,
52				       size_t size,
53				       int actual_bytes_written,
54				       errcode_t error);
55	int		refcount;
56	int		flags;
57	long		reserved[14];
58	void		*private_data;
59	void		*app_data;
60};
61
62struct struct_io_stats {
63	int			num_fields;
64	int			reserved;
65	unsigned long long	bytes_read;
66	unsigned long long	bytes_written;
67};
68
69struct struct_io_manager {
70	errcode_t magic;
71	const char *name;
72	errcode_t (*open)(const char *name, int flags, io_channel *channel);
73	errcode_t (*close)(io_channel channel);
74	errcode_t (*set_blksize)(io_channel channel, int blksize);
75	errcode_t (*read_blk)(io_channel channel, unsigned long block,
76			      int count, void *data);
77	errcode_t (*write_blk)(io_channel channel, unsigned long block,
78			       int count, const void *data);
79	errcode_t (*flush)(io_channel channel);
80	errcode_t (*write_byte)(io_channel channel, unsigned long offset,
81				int count, const void *data);
82	errcode_t (*set_option)(io_channel channel, const char *option,
83				const char *arg);
84	errcode_t (*get_stats)(io_channel channel, io_stats *io_stats);
85	errcode_t (*read_blk64)(io_channel channel, unsigned long long block,
86					int count, void *data);
87	errcode_t (*write_blk64)(io_channel channel, unsigned long long block,
88					int count, const void *data);
89	errcode_t (*discard)(io_channel channel, unsigned long long block,
90			     unsigned long long count);
91	long	reserved[16];
92};
93
94#define IO_FLAG_RW		0x0001
95#define IO_FLAG_EXCLUSIVE	0x0002
96#define IO_FLAG_DIRECT_IO	0x0004
97
98/*
99 * Convenience functions....
100 */
101#define io_channel_close(c) 		((c)->manager->close((c)))
102#define io_channel_set_blksize(c,s)	((c)->manager->set_blksize((c),s))
103#define io_channel_read_blk(c,b,n,d)	((c)->manager->read_blk((c),b,n,d))
104#define io_channel_write_blk(c,b,n,d)	((c)->manager->write_blk((c),b,n,d))
105#define io_channel_flush(c) 		((c)->manager->flush((c)))
106#define io_channel_bumpcount(c)		((c)->refcount++)
107
108/* io_manager.c */
109extern errcode_t io_channel_set_options(io_channel channel,
110					const char *options);
111extern errcode_t io_channel_write_byte(io_channel channel,
112				       unsigned long offset,
113				       int count, const void *data);
114extern errcode_t io_channel_read_blk64(io_channel channel,
115				       unsigned long long block,
116				       int count, void *data);
117extern errcode_t io_channel_write_blk64(io_channel channel,
118					unsigned long long block,
119					int count, const void *data);
120
121/* unix_io.c */
122extern io_manager unix_io_manager;
123
124/* undo_io.c */
125extern io_manager undo_io_manager;
126extern errcode_t set_undo_io_backing_manager(io_manager manager);
127extern errcode_t set_undo_io_backup_file(char *file_name);
128
129/* test_io.c */
130extern io_manager test_io_manager, test_io_backing_manager;
131extern void (*test_io_cb_read_blk)
132	(unsigned long block, int count, errcode_t err);
133extern void (*test_io_cb_write_blk)
134	(unsigned long block, int count, errcode_t err);
135extern void (*test_io_cb_read_blk64)
136	(unsigned long long block, int count, errcode_t err);
137extern void (*test_io_cb_write_blk64)
138	(unsigned long long block, int count, errcode_t err);
139extern void (*test_io_cb_set_blksize)
140	(int blksize, errcode_t err);
141
142#endif /* _EXT2FS_EXT2_IO_H */
143
144