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 #define CHANNEL_FLAGS_THREADS           0x08
  37 #define CHANNEL_FLAGS_NODISCARD         0x10
  38 #define CHANNEL_FLAGS_NOZEROOUT         0x20
  39
  40 #define io_channel_discard_zeroes_data(i) (i->flags & CHANNEL_FLAGS_DISCARD_ZEROES)
  41
  42 struct struct_io_channel {
  43         errcode_t       magic;
  44         io_manager      manager;
  45         char            *name;
  46         int             block_size;
  47         errcode_t       (*read_error)(io_channel channel,
  48                                       unsigned long block,
  49                                       int count,
  50                                       void *data,
  51                                       size_t size,
  52                                       int actual_bytes_read,
  53                                       errcode_t error);
  54         errcode_t       (*write_error)(io_channel channel,
  55                                        unsigned long block,
  56                                        int count,
  57                                        const void *data,
  58                                        size_t size,
  59                                        int actual_bytes_written,
  60                                        errcode_t error);
  61         int             refcount;
  62         unsigned int    flags;
  63         long            reserved[14];
  64         void            *private_data;
  65         void            *app_data;
  66         int             align;
  67 };
  68
  69 struct struct_io_stats {
  70         int                     num_fields;
  71         int                     reserved;
  72         unsigned long long      bytes_read;
  73         unsigned long long      bytes_written;
  74 };
  75
  76 struct struct_io_manager {
  77         errcode_t magic;
  78         const char *name;
  79         errcode_t (*open)(const char *name, int flags, io_channel *channel);
  80         errcode_t (*close)(io_channel channel);
  81         errcode_t (*set_blksize)(io_channel channel, int blksize);
  82         errcode_t (*read_blk)(io_channel channel, unsigned long block,
  83                               int count, void *data);
  84         errcode_t (*write_blk)(io_channel channel, unsigned long block,
  85                                int count, const void *data);
  86         errcode_t (*flush)(io_channel channel);
  87         errcode_t (*write_byte)(io_channel channel, unsigned long offset,
  88                                 int count, const void *data);
  89         errcode_t (*set_option)(io_channel channel, const char *option,
  90                                 const char *arg);
  91         errcode_t (*get_stats)(io_channel channel, io_stats *io_stats);
  92         errcode_t (*read_blk64)(io_channel channel, unsigned long long block,
  93                                         int count, void *data);
  94         errcode_t (*write_blk64)(io_channel channel, unsigned long long block,
  95                                         int count, const void *data);
  96         errcode_t (*discard)(io_channel channel, unsigned long long block,
  97                              unsigned long long count);
  98         errcode_t (*cache_readahead)(io_channel channel,
  99                                      unsigned long long block,
 100                                      unsigned long long count);
 101         errcode_t (*zeroout)(io_channel channel, unsigned long long block,
 102                              unsigned long long count);
 103         long    reserved[14];
 104 };
 105
 106 #define IO_FLAG_RW              0x0001
 107 #define IO_FLAG_EXCLUSIVE       0x0002
 108 #define IO_FLAG_DIRECT_IO       0x0004
 109 #define IO_FLAG_FORCE_BOUNCE    0x0008
 110 #define IO_FLAG_THREADS         0x0010
 111 #define IO_FLAG_NOCACHE         0x0020
 112
 113 /*
 114  * Convenience functions....
 115  */
 116 #define io_channel_close(c)             ((c)->manager->close((c)))
 117 #define io_channel_set_blksize(c,s)     ((c)->manager->set_blksize((c),s))
 118 #define io_channel_read_blk(c,b,n,d)    ((c)->manager->read_blk((c),b,n,d))
 119 #define io_channel_write_blk(c,b,n,d)   ((c)->manager->write_blk((c),b,n,d))
 120 #define io_channel_flush(c)             ((c)->manager->flush((c)))
 121 #define io_channel_bumpcount(c)         ((c)->refcount++)
 122
 123 /* io_manager.c */
 124 extern errcode_t io_channel_set_options(io_channel channel,
 125                                         const char *options);
 126 extern errcode_t io_channel_write_byte(io_channel channel,
 127                                        unsigned long offset,
 128                                        int count, const void *data);
 129 extern errcode_t io_channel_read_blk64(io_channel channel,
 130                                        unsigned long long block,
 131                                        int count, void *data);
 132 extern errcode_t io_channel_write_blk64(io_channel channel,
 133                                         unsigned long long block,
 134                                         int count, const void *data);
 135 extern errcode_t io_channel_discard(io_channel channel,
 136                                     unsigned long long block,
 137                                     unsigned long long count);
 138 extern errcode_t io_channel_zeroout(io_channel channel,
 139                                     unsigned long long block,
 140                                     unsigned long long count);
 141 extern errcode_t io_channel_alloc_buf(io_channel channel,
 142                                       int count, void *ptr);
 143 extern errcode_t io_channel_cache_readahead(io_channel io,
 144                                             unsigned long long block,
 145                                             unsigned long long count);
 146
 147 #ifdef _WIN32
 148 /* windows_io.c */
 149 extern io_manager windows_io_manager;
 150 #define default_io_manager windows_io_manager
 151 #else
 152 /* unix_io.c */
 153 extern io_manager unix_io_manager;
 154 extern io_manager unixfd_io_manager;
 155 #define default_io_manager unix_io_manager
 156 #endif
 157
 158 /* sparse_io.c */
 159 extern io_manager sparse_io_manager;
 160 extern io_manager sparsefd_io_manager;
 161
 162 /* undo_io.c */
 163 extern io_manager undo_io_manager;
 164 extern errcode_t set_undo_io_backing_manager(io_manager manager);
 165 extern errcode_t set_undo_io_backup_file(char *file_name);
 166
 167 /* test_io.c */
 168 extern io_manager test_io_manager, test_io_backing_manager;
 169 extern void (*test_io_cb_read_blk)
 170         (unsigned long block, int count, errcode_t err);
 171 extern void (*test_io_cb_write_blk)
 172         (unsigned long block, int count, errcode_t err);
 173 extern void (*test_io_cb_read_blk64)
 174         (unsigned long long block, int count, errcode_t err);
 175 extern void (*test_io_cb_write_blk64)
 176         (unsigned long long block, int count, errcode_t err);
 177 extern void (*test_io_cb_set_blksize)
 178         (int blksize, errcode_t err);
 179
 180 #endif /* _EXT2FS_EXT2_IO_H */
 181