lib/ext2fs/ext2_io.h

   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
  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         errcode_t (*discard)(io_channel channel, unsigned long long block,
  87                              unsigned long long count);
  88         long    reserved[16];
  89 };
  90
  91 #define IO_FLAG_RW              0x0001
  92 #define IO_FLAG_EXCLUSIVE       0x0002
  93 #define IO_FLAG_DIRECT_IO       0x0004
  94
  95 /*
  96  * Convenience functions....
  97  */
  98 #define io_channel_close(c)             ((c)->manager->close((c)))
  99 #define io_channel_set_blksize(c,s)     ((c)->manager->set_blksize((c),s))
 100 #define io_channel_read_blk(c,b,n,d)    ((c)->manager->read_blk((c),b,n,d))
 101 #define io_channel_write_blk(c,b,n,d)   ((c)->manager->write_blk((c),b,n,d))
 102 #define io_channel_flush(c)             ((c)->manager->flush((c)))
 103 #define io_channel_bumpcount(c)         ((c)->refcount++)
 104
 105 /* io_manager.c */
 106 extern errcode_t io_channel_set_options(io_channel channel,
 107                                         const char *options);
 108 extern errcode_t io_channel_write_byte(io_channel channel,
 109                                        unsigned long offset,
 110                                        int count, const void *data);
 111 extern errcode_t io_channel_read_blk64(io_channel channel,
 112                                        unsigned long long block,
 113                                        int count, void *data);
 114 extern errcode_t io_channel_write_blk64(io_channel channel,
 115                                         unsigned long long block,
 116                                         int count, const void *data);
 117
 118 /* unix_io.c */
 119 extern io_manager unix_io_manager;
 120
 121 /* undo_io.c */
 122 extern io_manager undo_io_manager;
 123 extern errcode_t set_undo_io_backing_manager(io_manager manager);
 124 extern errcode_t set_undo_io_backup_file(char *file_name);
 125
 126 /* test_io.c */
 127 extern io_manager test_io_manager, test_io_backing_manager;
 128 extern void (*test_io_cb_read_blk)
 129         (unsigned long block, int count, errcode_t err);
 130 extern void (*test_io_cb_write_blk)
 131         (unsigned long block, int count, errcode_t err);
 132 extern void (*test_io_cb_read_blk64)
 133         (unsigned long long block, int count, errcode_t err);
 134 extern void (*test_io_cb_write_blk64)
 135         (unsigned long long block, int count, errcode_t err);
 136 extern void (*test_io_cb_set_blksize)
 137         (int blksize, errcode_t err);
 138
 139 #endif /* _EXT2FS_EXT2_IO_H */
 140