2 * io.h --- the I/O manager abstraction
4 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
7 * This file may be redistributed under the terms of the GNU Library
8 * General Public License, version 2.
12 #ifndef _EXT2FS_EXT2_IO_H
13 #define _EXT2FS_EXT2_IO_H
16 * ext2_loff_t is defined here since unix_io.c needs it.
18 #if defined(__GNUC__) || defined(HAS_LONG_LONG)
19 typedef long long ext2_loff_t;
21 typedef long ext2_loff_t;
25 ext2_loff_t ext2fs_llseek (int, ext2_loff_t, int);
27 typedef struct struct_io_manager *io_manager;
28 typedef struct struct_io_channel *io_channel;
29 typedef struct struct_io_stats *io_stats;
31 #define CHANNEL_FLAGS_WRITETHROUGH 0x01
32 #define CHANNEL_FLAGS_DISCARD_ZEROES 0x02
34 #define io_channel_discard_zeroes_data(i) (i->flags & CHANNEL_FLAGS_DISCARD_ZEROES)
36 struct struct_io_channel {
41 errcode_t (*read_error)(io_channel channel,
46 int actual_bytes_read,
48 errcode_t (*write_error)(io_channel channel,
53 int actual_bytes_written,
62 struct struct_io_stats {
65 unsigned long long bytes_read;
66 unsigned long long bytes_written;
69 struct struct_io_manager {
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,
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);
94 #define IO_FLAG_RW 0x0001
95 #define IO_FLAG_EXCLUSIVE 0x0002
96 #define IO_FLAG_DIRECT_IO 0x0004
99 * Convenience functions....
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++)
109 extern errcode_t io_channel_set_options(io_channel channel,
110 const char *options);
111 extern errcode_t io_channel_write_byte(io_channel channel,
112 unsigned long offset,
113 int count, const void *data);
114 extern errcode_t io_channel_read_blk64(io_channel channel,
115 unsigned long long block,
116 int count, void *data);
117 extern errcode_t io_channel_write_blk64(io_channel channel,
118 unsigned long long block,
119 int count, const void *data);
120 extern errcode_t io_channel_discard(io_channel channel,
121 unsigned long long block,
122 unsigned long long count);
125 extern io_manager unix_io_manager;
128 extern io_manager undo_io_manager;
129 extern errcode_t set_undo_io_backing_manager(io_manager manager);
130 extern errcode_t set_undo_io_backup_file(char *file_name);
133 extern io_manager test_io_manager, test_io_backing_manager;
134 extern void (*test_io_cb_read_blk)
135 (unsigned long block, int count, errcode_t err);
136 extern void (*test_io_cb_write_blk)
137 (unsigned long block, int count, errcode_t err);
138 extern void (*test_io_cb_read_blk64)
139 (unsigned long long block, int count, errcode_t err);
140 extern void (*test_io_cb_write_blk64)
141 (unsigned long long block, int count, errcode_t err);
142 extern void (*test_io_cb_set_blksize)
143 (int blksize, errcode_t err);
145 #endif /* _EXT2FS_EXT2_IO_H */