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) 19 typedef long long ext2_loff_t; 20 #else 21 typedef long ext2_loff_t; 22 #endif 23 24 /* llseek.c */ 25 ext2_loff_t ext2fs_llseek (int, ext2_loff_t, int); 26 27 typedef struct struct_io_manager *io_manager; 28 typedef struct struct_io_channel *io_channel; 29 typedef struct struct_io_stats *io_stats; 30 31 #define CHANNEL_FLAGS_WRITETHROUGH 0x01 32 33 struct 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 59 struct struct_io_stats { 60 int num_fields; 61 int reserved; 62 unsigned long long bytes_read; 63 unsigned long long bytes_written; 64 }; 65 66 struct 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 */ 103 extern errcode_t io_channel_set_options(io_channel channel, 104 const char *options); 105 extern errcode_t io_channel_write_byte(io_channel channel, 106 unsigned long offset, 107 int count, const void *data); 108 extern errcode_t io_channel_read_blk64(io_channel channel, 109 unsigned long long block, 110 int count, void *data); 111 extern 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 */ 116 extern io_manager unix_io_manager; 117 118 /* undo_io.c */ 119 extern io_manager undo_io_manager; 120 extern errcode_t set_undo_io_backing_manager(io_manager manager); 121 extern errcode_t set_undo_io_backup_file(char *file_name); 122 123 /* test_io.c */ 124 extern io_manager test_io_manager, test_io_backing_manager; 125 extern void (*test_io_cb_read_blk) 126 (unsigned long block, int count, errcode_t err); 127 extern void (*test_io_cb_write_blk) 128 (unsigned long block, int count, errcode_t err); 129 extern void (*test_io_cb_set_blksize) 130 (int blksize, errcode_t err); 131 132 #endif /* _EXT2FS_EXT2_IO_H */ 133 134