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) 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 #define CHANNEL_FLAGS_DISCARD_ZEROES 0x02 33 #define CHANNEL_FLAGS_BLOCK_DEVICE 0x04 34 35 #define io_channel_discard_zeroes_data(i) (i->flags & CHANNEL_FLAGS_DISCARD_ZEROES) 36 37 struct struct_io_channel { 38 errcode_t magic; 39 io_manager manager; 40 char *name; 41 int block_size; 42 errcode_t (*read_error)(io_channel channel, 43 unsigned long block, 44 int count, 45 void *data, 46 size_t size, 47 int actual_bytes_read, 48 errcode_t error); 49 errcode_t (*write_error)(io_channel channel, 50 unsigned long block, 51 int count, 52 const void *data, 53 size_t size, 54 int actual_bytes_written, 55 errcode_t error); 56 int refcount; 57 int flags; 58 long reserved[14]; 59 void *private_data; 60 void *app_data; 61 int align; 62 }; 63 64 struct struct_io_stats { 65 int num_fields; 66 int reserved; 67 unsigned long long bytes_read; 68 unsigned long long bytes_written; 69 }; 70 71 struct struct_io_manager { 72 errcode_t magic; 73 const char *name; 74 errcode_t (*open)(const char *name, int flags, io_channel *channel); 75 errcode_t (*close)(io_channel channel); 76 errcode_t (*set_blksize)(io_channel channel, int blksize); 77 errcode_t (*read_blk)(io_channel channel, unsigned long block, 78 int count, void *data); 79 errcode_t (*write_blk)(io_channel channel, unsigned long block, 80 int count, const void *data); 81 errcode_t (*flush)(io_channel channel); 82 errcode_t (*write_byte)(io_channel channel, unsigned long offset, 83 int count, const void *data); 84 errcode_t (*set_option)(io_channel channel, const char *option, 85 const char *arg); 86 errcode_t (*get_stats)(io_channel channel, io_stats *io_stats); 87 errcode_t (*read_blk64)(io_channel channel, unsigned long long block, 88 int count, void *data); 89 errcode_t (*write_blk64)(io_channel channel, unsigned long long block, 90 int count, const void *data); 91 errcode_t (*discard)(io_channel channel, unsigned long long block, 92 unsigned long long count); 93 long reserved[16]; 94 }; 95 96 #define IO_FLAG_RW 0x0001 97 #define IO_FLAG_EXCLUSIVE 0x0002 98 #define IO_FLAG_DIRECT_IO 0x0004 99 100 /* 101 * Convenience functions.... 102 */ 103 #define io_channel_close(c) ((c)->manager->close((c))) 104 #define io_channel_set_blksize(c,s) ((c)->manager->set_blksize((c),s)) 105 #define io_channel_read_blk(c,b,n,d) ((c)->manager->read_blk((c),b,n,d)) 106 #define io_channel_write_blk(c,b,n,d) ((c)->manager->write_blk((c),b,n,d)) 107 #define io_channel_flush(c) ((c)->manager->flush((c))) 108 #define io_channel_bumpcount(c) ((c)->refcount++) 109 110 /* io_manager.c */ 111 extern errcode_t io_channel_set_options(io_channel channel, 112 const char *options); 113 extern errcode_t io_channel_write_byte(io_channel channel, 114 unsigned long offset, 115 int count, const void *data); 116 extern errcode_t io_channel_read_blk64(io_channel channel, 117 unsigned long long block, 118 int count, void *data); 119 extern errcode_t io_channel_write_blk64(io_channel channel, 120 unsigned long long block, 121 int count, const void *data); 122 extern errcode_t io_channel_discard(io_channel channel, 123 unsigned long long block, 124 unsigned long long count); 125 extern errcode_t io_channel_alloc_buf(io_channel channel, 126 int count, void *ptr); 127 128 /* unix_io.c */ 129 extern io_manager unix_io_manager; 130 131 /* undo_io.c */ 132 extern io_manager undo_io_manager; 133 extern errcode_t set_undo_io_backing_manager(io_manager manager); 134 extern errcode_t set_undo_io_backup_file(char *file_name); 135 136 /* test_io.c */ 137 extern io_manager test_io_manager, test_io_backing_manager; 138 extern void (*test_io_cb_read_blk) 139 (unsigned long block, int count, errcode_t err); 140 extern void (*test_io_cb_write_blk) 141 (unsigned long block, int count, errcode_t err); 142 extern void (*test_io_cb_read_blk64) 143 (unsigned long long block, int count, errcode_t err); 144 extern void (*test_io_cb_write_blk64) 145 (unsigned long long block, int count, errcode_t err); 146 extern void (*test_io_cb_set_blksize) 147 (int blksize, errcode_t err); 148 149 #endif /* _EXT2FS_EXT2_IO_H */ 150 151
