1/* vi: set sw=4 ts=4: */ 2/* 3 * io.h --- the I/O manager abstraction 4 * 5 * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o. 6 * 7 * %Begin-Header% 8 * This file may be redistributed under the terms of the GNU Public 9 * License. 10 * %End-Header% 11 */ 12#ifndef EXT2FS_EXT2_IO_H 13#define EXT2FS_EXT2_IO_H 1 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 */ 25/* ext2_loff_t ext2fs_llseek (int, ext2_loff_t, int); */ 26#ifdef CONFIG_LFS 27# define ext2fs_llseek lseek64 28#else 29# define ext2fs_llseek lseek 30#endif 31 32typedef struct struct_io_manager *io_manager; 33typedef struct struct_io_channel *io_channel; 34 35#define CHANNEL_FLAGS_WRITETHROUGH 0x01 36 37struct 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 int reserved[14]; 59 void *private_data; 60 void *app_data; 61}; 62 63struct struct_io_manager { 64 errcode_t magic; 65 const char *name; 66 errcode_t (*open)(const char *name, int flags, io_channel *channel); 67 errcode_t (*close)(io_channel channel); 68 errcode_t (*set_blksize)(io_channel channel, int blksize); 69 errcode_t (*read_blk)(io_channel channel, unsigned long block, 70 int count, void *data); 71 errcode_t (*write_blk)(io_channel channel, unsigned long block, 72 int count, const void *data); 73 errcode_t (*flush)(io_channel channel); 74 errcode_t (*write_byte)(io_channel channel, unsigned long offset, 75 int count, const void *data); 76 errcode_t (*set_option)(io_channel channel, const char *option, 77 const char *arg); 78 int reserved[14]; 79}; 80 81#define IO_FLAG_RW 1 82 83/* 84 * Convenience functions.... 85 */ 86#define io_channel_close(c) ((c)->manager->close((c))) 87#define io_channel_set_blksize(c,s) ((c)->manager->set_blksize((c),s)) 88#define io_channel_read_blk(c,b,n,d) ((c)->manager->read_blk((c),b,n,d)) 89#define io_channel_write_blk(c,b,n,d) ((c)->manager->write_blk((c),b,n,d)) 90#define io_channel_flush(c) ((c)->manager->flush((c))) 91#define io_channel_bumpcount(c) ((c)->refcount++) 92 93/* io_manager.c */ 94extern errcode_t io_channel_set_options(io_channel channel, 95 const char *options); 96extern errcode_t io_channel_write_byte(io_channel channel, 97 unsigned long offset, 98 int count, const void *data); 99 100/* unix_io.c */ 101extern io_manager unix_io_manager; 102 103/* test_io.c */ 104extern io_manager test_io_manager, test_io_backing_manager; 105extern void (*test_io_cb_read_blk) 106 (unsigned long block, int count, errcode_t err); 107extern void (*test_io_cb_write_blk) 108 (unsigned long block, int count, errcode_t err); 109extern void (*test_io_cb_set_blksize) 110 (int blksize, errcode_t err); 111 112#endif 113