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
15 #include <ext2fs/ext2_types.h>
18 * ext2_loff_t is defined here since unix_io.c needs it.
20 #if defined(__GNUC__) || defined(HAS_LONG_LONG)
21 typedef long long ext2_loff_t;
23 typedef long ext2_loff_t;
27 ext2_loff_t ext2fs_llseek (int, ext2_loff_t, int);
29 typedef struct struct_io_manager *io_manager;
30 typedef struct struct_io_channel *io_channel;
31 typedef struct struct_io_stats *io_stats;
33 #define CHANNEL_FLAGS_WRITETHROUGH 0x01
34 #define CHANNEL_FLAGS_DISCARD_ZEROES 0x02
35 #define CHANNEL_FLAGS_BLOCK_DEVICE 0x04
37 #define io_channel_discard_zeroes_data(i) (i->flags & CHANNEL_FLAGS_DISCARD_ZEROES)
39 struct struct_io_channel {
44 errcode_t (*read_error)(io_channel channel,
49 int actual_bytes_read,
51 errcode_t (*write_error)(io_channel channel,
56 int actual_bytes_written,
66 struct struct_io_stats {
69 unsigned long long bytes_read;
70 unsigned long long bytes_written;
73 struct struct_io_manager {
76 errcode_t (*open)(const char *name, int flags, io_channel *channel);
77 errcode_t (*close)(io_channel channel);
78 errcode_t (*set_blksize)(io_channel channel, int blksize);
79 errcode_t (*read_blk)(io_channel channel, unsigned long block,
80 int count, void *data);
81 errcode_t (*write_blk)(io_channel channel, unsigned long block,
82 int count, const void *data);
83 errcode_t (*flush)(io_channel channel);
84 errcode_t (*write_byte)(io_channel channel, unsigned long offset,
85 int count, const void *data);
86 errcode_t (*set_option)(io_channel channel, const char *option,
88 errcode_t (*get_stats)(io_channel channel, io_stats *io_stats);
89 errcode_t (*read_blk64)(io_channel channel, unsigned long long block,
90 int count, void *data);
91 errcode_t (*write_blk64)(io_channel channel, unsigned long long block,
92 int count, const void *data);
93 errcode_t (*discard)(io_channel channel, unsigned long long block,
94 unsigned long long count);
95 errcode_t (*cache_readahead)(io_channel channel,
96 unsigned long long block,
97 unsigned long long count);
98 errcode_t (*zeroout)(io_channel channel, unsigned long long block,
99 unsigned long long count);
103 #define IO_FLAG_RW 0x0001
104 #define IO_FLAG_EXCLUSIVE 0x0002
105 #define IO_FLAG_DIRECT_IO 0x0004
106 #define IO_FLAG_FORCE_BOUNCE 0x0008
109 * Convenience functions....
111 #define io_channel_close(c) ((c)->manager->close((c)))
112 #define io_channel_set_blksize(c,s) ((c)->manager->set_blksize((c),s))
113 #define io_channel_read_blk(c,b,n,d) ((c)->manager->read_blk((c),b,n,d))
114 #define io_channel_write_blk(c,b,n,d) ((c)->manager->write_blk((c),b,n,d))
115 #define io_channel_flush(c) ((c)->manager->flush((c)))
116 #define io_channel_bumpcount(c) ((c)->refcount++)
119 extern errcode_t io_channel_set_options(io_channel channel,
120 const char *options);
121 extern errcode_t io_channel_write_byte(io_channel channel,
122 unsigned long offset,
123 int count, const void *data);
124 extern errcode_t io_channel_read_blk64(io_channel channel,
125 unsigned long long block,
126 int count, void *data);
127 extern errcode_t io_channel_write_blk64(io_channel channel,
128 unsigned long long block,
129 int count, const void *data);
130 extern errcode_t io_channel_discard(io_channel channel,
131 unsigned long long block,
132 unsigned long long count);
133 extern errcode_t io_channel_zeroout(io_channel channel,
134 unsigned long long block,
135 unsigned long long count);
136 extern errcode_t io_channel_alloc_buf(io_channel channel,
137 int count, void *ptr);
138 extern errcode_t io_channel_cache_readahead(io_channel io,
139 unsigned long long block,
140 unsigned long long count);
143 extern io_manager unix_io_manager;
144 extern io_manager unixfd_io_manager;
147 extern io_manager sparse_io_manager;
148 extern io_manager sparsefd_io_manager;
151 extern io_manager undo_io_manager;
152 extern errcode_t set_undo_io_backing_manager(io_manager manager);
153 extern errcode_t set_undo_io_backup_file(char *file_name);
156 extern io_manager test_io_manager, test_io_backing_manager;
157 extern void (*test_io_cb_read_blk)
158 (unsigned long block, int count, errcode_t err);
159 extern void (*test_io_cb_write_blk)
160 (unsigned long block, int count, errcode_t err);
161 extern void (*test_io_cb_read_blk64)
162 (unsigned long long block, int count, errcode_t err);
163 extern void (*test_io_cb_write_blk64)
164 (unsigned long long block, int count, errcode_t err);
165 extern void (*test_io_cb_set_blksize)
166 (int blksize, errcode_t err);
168 #endif /* _EXT2FS_EXT2_IO_H */