1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * inode_io.c --- This is allows an inode in an ext2 filesystem image
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4 | * to be accessed via the I/O manager interface.
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5 | *
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6 | * Copyright (C) 2002 Theodore Ts'o.
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7 | *
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8 | * %Begin-Header%
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9 | * This file may be redistributed under the terms of the GNU Public
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10 | * License.
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11 | * %End-Header%
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12 | */
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13 |
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14 | #include <stdio.h>
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15 | #include <string.h>
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16 | #if HAVE_UNISTD_H
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17 | #include <unistd.h>
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18 | #endif
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19 | #if HAVE_ERRNO_H
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20 | #include <errno.h>
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21 | #endif
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22 | #include <time.h>
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23 |
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24 | #include "ext2_fs.h"
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25 | #include "ext2fs.h"
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26 |
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27 | /*
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28 | * For checking structure magic numbers...
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29 | */
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30 |
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31 | #define EXT2_CHECK_MAGIC(struct, code) \
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32 | if ((struct)->magic != (code)) return (code)
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33 |
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34 | struct inode_private_data {
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35 | int magic;
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36 | char name[32];
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37 | ext2_file_t file;
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38 | ext2_filsys fs;
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39 | ext2_ino_t ino;
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40 | struct ext2_inode inode;
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41 | int flags;
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42 | struct inode_private_data *next;
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43 | };
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44 |
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45 | #define CHANNEL_HAS_INODE 0x8000
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46 |
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47 | static struct inode_private_data *top_intern;
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48 | static int ino_unique = 0;
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49 |
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50 | static errcode_t inode_open(const char *name, int flags, io_channel *channel);
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51 | static errcode_t inode_close(io_channel channel);
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52 | static errcode_t inode_set_blksize(io_channel channel, int blksize);
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53 | static errcode_t inode_read_blk(io_channel channel, unsigned long block,
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54 | int count, void *data);
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55 | static errcode_t inode_write_blk(io_channel channel, unsigned long block,
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56 | int count, const void *data);
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57 | static errcode_t inode_flush(io_channel channel);
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58 | static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
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59 | int size, const void *data);
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60 |
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61 | static struct struct_io_manager struct_inode_manager = {
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62 | EXT2_ET_MAGIC_IO_MANAGER,
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63 | "Inode I/O Manager",
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64 | inode_open,
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65 | inode_close,
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66 | inode_set_blksize,
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67 | inode_read_blk,
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68 | inode_write_blk,
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69 | inode_flush,
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70 | inode_write_byte
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71 | };
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72 |
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73 | io_manager inode_io_manager = &struct_inode_manager;
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74 |
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75 | errcode_t ext2fs_inode_io_intern2(ext2_filsys fs, ext2_ino_t ino,
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76 | struct ext2_inode *inode,
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77 | char **name)
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78 | {
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79 | struct inode_private_data *data;
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80 | errcode_t retval;
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81 |
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82 | if ((retval = ext2fs_get_mem(sizeof(struct inode_private_data),
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83 | &data)))
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84 | return retval;
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85 | data->magic = EXT2_ET_MAGIC_INODE_IO_CHANNEL;
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86 | sprintf(data->name, "%u:%d", ino, ino_unique++);
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87 | data->file = 0;
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88 | data->fs = fs;
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89 | data->ino = ino;
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90 | data->flags = 0;
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91 | if (inode) {
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92 | memcpy(&data->inode, inode, sizeof(struct ext2_inode));
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93 | data->flags |= CHANNEL_HAS_INODE;
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94 | }
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95 | data->next = top_intern;
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96 | top_intern = data;
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97 | *name = data->name;
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98 | return 0;
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99 | }
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100 |
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101 | errcode_t ext2fs_inode_io_intern(ext2_filsys fs, ext2_ino_t ino,
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102 | char **name)
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103 | {
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104 | return ext2fs_inode_io_intern2(fs, ino, NULL, name);
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105 | }
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106 |
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107 |
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108 | static errcode_t inode_open(const char *name, int flags, io_channel *channel)
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109 | {
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110 | io_channel io = NULL;
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111 | struct inode_private_data *prev, *data = NULL;
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112 | errcode_t retval;
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113 | int open_flags;
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114 |
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115 | if (name == 0)
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116 | return EXT2_ET_BAD_DEVICE_NAME;
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117 |
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118 | for (data = top_intern, prev = NULL; data;
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119 | prev = data, data = data->next)
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120 | if (strcmp(name, data->name) == 0)
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121 | break;
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122 | if (!data)
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123 | return ENOENT;
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124 | if (prev)
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125 | prev->next = data->next;
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126 | else
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127 | top_intern = data->next;
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128 |
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129 | retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
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130 | if (retval)
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131 | goto cleanup;
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132 | memset(io, 0, sizeof(struct struct_io_channel));
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133 |
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134 | io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
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135 | io->manager = inode_io_manager;
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136 | retval = ext2fs_get_mem(strlen(name)+1, &io->name);
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137 | if (retval)
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138 | goto cleanup;
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139 |
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140 | strcpy(io->name, name);
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141 | io->private_data = data;
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142 | io->block_size = 1024;
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143 | io->read_error = 0;
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144 | io->write_error = 0;
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145 | io->refcount = 1;
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146 |
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147 | open_flags = (flags & IO_FLAG_RW) ? EXT2_FILE_WRITE : 0;
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148 | retval = ext2fs_file_open2(data->fs, data->ino,
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149 | (data->flags & CHANNEL_HAS_INODE) ?
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150 | &data->inode : 0, open_flags,
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151 | &data->file);
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152 | if (retval)
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153 | goto cleanup;
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154 |
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155 | *channel = io;
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156 | return 0;
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157 |
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158 | cleanup:
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159 | if (data) {
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160 | ext2fs_free_mem(&data);
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161 | }
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162 | if (io)
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163 | ext2fs_free_mem(&io);
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164 | return retval;
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165 | }
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166 |
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167 | static errcode_t inode_close(io_channel channel)
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168 | {
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169 | struct inode_private_data *data;
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170 | errcode_t retval = 0;
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171 |
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172 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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173 | data = (struct inode_private_data *) channel->private_data;
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174 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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175 |
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176 | if (--channel->refcount > 0)
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177 | return 0;
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178 |
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179 | retval = ext2fs_file_close(data->file);
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180 |
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181 | ext2fs_free_mem(&channel->private_data);
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182 | if (channel->name)
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183 | ext2fs_free_mem(&channel->name);
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184 | ext2fs_free_mem(&channel);
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185 | return retval;
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186 | }
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187 |
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188 | static errcode_t inode_set_blksize(io_channel channel, int blksize)
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189 | {
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190 | struct inode_private_data *data;
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191 |
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192 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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193 | data = (struct inode_private_data *) channel->private_data;
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194 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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195 |
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196 | channel->block_size = blksize;
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197 | return 0;
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198 | }
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199 |
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200 |
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201 | static errcode_t inode_read_blk(io_channel channel, unsigned long block,
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202 | int count, void *buf)
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203 | {
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204 | struct inode_private_data *data;
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205 | errcode_t retval;
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206 |
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207 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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208 | data = (struct inode_private_data *) channel->private_data;
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209 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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210 |
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211 | if ((retval = ext2fs_file_lseek(data->file,
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212 | block * channel->block_size,
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213 | EXT2_SEEK_SET, 0)))
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214 | return retval;
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215 |
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216 | count = (count < 0) ? -count : (count * channel->block_size);
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217 |
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218 | return ext2fs_file_read(data->file, buf, count, 0);
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219 | }
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220 |
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221 | static errcode_t inode_write_blk(io_channel channel, unsigned long block,
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222 | int count, const void *buf)
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223 | {
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224 | struct inode_private_data *data;
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225 | errcode_t retval;
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226 |
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227 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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228 | data = (struct inode_private_data *) channel->private_data;
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229 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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230 |
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231 | if ((retval = ext2fs_file_lseek(data->file,
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232 | block * channel->block_size,
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233 | EXT2_SEEK_SET, 0)))
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234 | return retval;
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235 |
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236 | count = (count < 0) ? -count : (count * channel->block_size);
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237 |
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238 | return ext2fs_file_write(data->file, buf, count, 0);
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239 | }
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240 |
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241 | static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
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242 | int size, const void *buf)
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243 | {
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244 | struct inode_private_data *data;
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245 | errcode_t retval = 0;
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246 |
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247 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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248 | data = (struct inode_private_data *) channel->private_data;
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249 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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250 |
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251 | if ((retval = ext2fs_file_lseek(data->file, offset,
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252 | EXT2_SEEK_SET, 0)))
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253 | return retval;
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254 |
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255 | return ext2fs_file_write(data->file, buf, size, 0);
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256 | }
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257 |
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258 | /*
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259 | * Flush data buffers to disk.
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260 | */
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261 | static errcode_t inode_flush(io_channel channel)
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262 | {
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263 | struct inode_private_data *data;
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264 |
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265 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
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266 | data = (struct inode_private_data *) channel->private_data;
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267 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
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268 |
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269 | return ext2fs_file_flush(data->file);
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270 | }
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271 |
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