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 #include <ext2fs/ext2_types.h>
  16
  17 /*
  18  * ext2_loff_t is defined here since unix_io.c needs it.
  19  */
  20 #if defined(__GNUC__) || defined(HAS_LONG_LONG)
  21 typedef long long       ext2_loff_t;
  22 #else
  23 typedef long            ext2_loff_t;
  24 #endif
  25
  26 /* llseek.c */
  27 ext2_loff_t ext2fs_llseek (int, ext2_loff_t, int);
  28
  29 typedef struct struct_io_manager *io_manager;
  30 typedef struct struct_io_channel *io_channel;
  31 typedef struct struct_io_stats *io_stats;
  32
  33 #define CHANNEL_FLAGS_WRITETHROUGH      0x01
  34 #define CHANNEL_FLAGS_DISCARD_ZEROES    0x02
  35 #define CHANNEL_FLAGS_BLOCK_DEVICE      0x04
  36
  37 #define io_channel_discard_zeroes_data(i) (i->flags & CHANNEL_FLAGS_DISCARD_ZEROES)
  38
  39 struct struct_io_channel {
  40         errcode_t       magic;
  41         io_manager      manager;
  42         char            *name;
  43         int             block_size;
  44         errcode_t       (*read_error)(io_channel channel,
  45                                       unsigned long block,
  46                                       int count,
  47                                       void *data,
  48                                       size_t size,
  49                                       int actual_bytes_read,
  50                                       errcode_t error);
  51         errcode_t       (*write_error)(io_channel channel,
  52                                        unsigned long block,
  53                                        int count,
  54                                        const void *data,
  55                                        size_t size,
  56                                        int actual_bytes_written,
  57                                        errcode_t error);
  58         int             refcount;
  59         int             flags;
  60         long            reserved[14];
  61         void            *private_data;
  62         void            *app_data;
  63         int             align;
  64 };
  65
  66 struct struct_io_stats {
  67         int                     num_fields;
  68         int                     reserved;
  69         unsigned long long      bytes_read;
  70         unsigned long long      bytes_written;
  71 };
  72
  73 struct struct_io_manager {
  74         errcode_t magic;
  75         const char *name;
  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,
  87                                 const char *arg);
  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);
 100         long    reserved[14];
 101 };
 102
 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
 107
 108 /*
 109  * Convenience functions....
 110  */
 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++)
 117
 118 /* io_manager.c */
 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);
 141
 142 /* unix_io.c */
 143 extern io_manager unix_io_manager;
 144 extern io_manager unixfd_io_manager;
 145
 146 /* sparse_io.c */
 147 extern io_manager sparse_io_manager;
 148 extern io_manager sparsefd_io_manager;
 149
 150 /* undo_io.c */
 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);
 154
 155 /* test_io.c */
 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);
 167
 168 #endif /* _EXT2FS_EXT2_IO_H */
 169