1 | /* vi: set sw=4 ts=4: */
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2 | /*
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3 | * unix_io.c --- This is the Unix (well, really POSIX) implementation
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4 | * of the I/O manager.
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5 | *
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6 | * Implements a one-block write-through cache.
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7 | *
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8 | * Includes support for Windows NT support under Cygwin.
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9 | *
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10 | * Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001,
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11 | * 2002 by Theodore Ts'o.
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12 | *
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13 | * %Begin-Header%
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14 | * This file may be redistributed under the terms of the GNU Public
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15 | * License.
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16 | * %End-Header%
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17 | */
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18 |
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19 | #include <stdio.h>
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20 | #include <string.h>
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21 | #if HAVE_UNISTD_H
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22 | #include <unistd.h>
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23 | #endif
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24 | #if HAVE_ERRNO_H
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25 | #include <errno.h>
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26 | #endif
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27 | #include <fcntl.h>
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28 | #include <time.h>
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29 | #ifdef __linux__
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30 | #include <sys/utsname.h>
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31 | #endif
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32 | #if HAVE_SYS_STAT_H
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33 | #include <sys/stat.h>
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34 | #endif
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35 | #if HAVE_SYS_TYPES_H
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36 | #include <sys/types.h>
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37 | #endif
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38 | #include <sys/resource.h>
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39 |
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40 | #include "ext2_fs.h"
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41 | #include "ext2fs.h"
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42 |
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43 | /*
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44 | * For checking structure magic numbers...
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45 | */
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46 |
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47 | #define EXT2_CHECK_MAGIC(struct, code) \
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48 | if ((struct)->magic != (code)) return (code)
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49 |
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50 | struct unix_cache {
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51 | char *buf;
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52 | unsigned long block;
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53 | int access_time;
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54 | unsigned dirty:1;
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55 | unsigned in_use:1;
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56 | };
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57 |
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58 | #define CACHE_SIZE 8
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59 | #define WRITE_DIRECT_SIZE 4 /* Must be smaller than CACHE_SIZE */
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60 | #define READ_DIRECT_SIZE 4 /* Should be smaller than CACHE_SIZE */
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61 |
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62 | struct unix_private_data {
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63 | int magic;
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64 | int dev;
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65 | int flags;
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66 | int access_time;
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67 | ext2_loff_t offset;
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68 | struct unix_cache cache[CACHE_SIZE];
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69 | };
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70 |
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71 | static errcode_t unix_open(const char *name, int flags, io_channel *channel);
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72 | static errcode_t unix_close(io_channel channel);
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73 | static errcode_t unix_set_blksize(io_channel channel, int blksize);
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74 | static errcode_t unix_read_blk(io_channel channel, unsigned long block,
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75 | int count, void *data);
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76 | static errcode_t unix_write_blk(io_channel channel, unsigned long block,
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77 | int count, const void *data);
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78 | static errcode_t unix_flush(io_channel channel);
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79 | static errcode_t unix_write_byte(io_channel channel, unsigned long offset,
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80 | int size, const void *data);
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81 | static errcode_t unix_set_option(io_channel channel, const char *option,
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82 | const char *arg);
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83 |
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84 | static void reuse_cache(io_channel channel, struct unix_private_data *data,
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85 | struct unix_cache *cache, unsigned long block);
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86 |
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87 | /* __FreeBSD_kernel__ is defined by GNU/kFreeBSD - the FreeBSD kernel
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88 | * does not know buffered block devices - everything is raw. */
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89 | #if defined(__CYGWIN__) || defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
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90 | #define NEED_BOUNCE_BUFFER
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91 | #else
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92 | #undef NEED_BOUNCE_BUFFER
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93 | #endif
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94 |
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95 | static struct struct_io_manager struct_unix_manager = {
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96 | EXT2_ET_MAGIC_IO_MANAGER,
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97 | "Unix I/O Manager",
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98 | unix_open,
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99 | unix_close,
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100 | unix_set_blksize,
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101 | unix_read_blk,
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102 | unix_write_blk,
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103 | unix_flush,
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104 | #ifdef NEED_BOUNCE_BUFFER
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105 | 0,
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106 | #else
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107 | unix_write_byte,
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108 | #endif
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109 | unix_set_option
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110 | };
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111 |
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112 | io_manager unix_io_manager = &struct_unix_manager;
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113 |
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114 | /*
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115 | * Here are the raw I/O functions
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116 | */
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117 | #ifndef NEED_BOUNCE_BUFFER
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118 | static errcode_t raw_read_blk(io_channel channel,
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119 | struct unix_private_data *data,
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120 | unsigned long block,
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121 | int count, void *buf)
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122 | {
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123 | errcode_t retval;
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124 | ssize_t size;
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125 | ext2_loff_t location;
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126 | int actual = 0;
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127 |
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128 | size = (count < 0) ? -count : count * channel->block_size;
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129 | location = ((ext2_loff_t) block * channel->block_size) + data->offset;
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130 | if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
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131 | retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
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132 | goto error_out;
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133 | }
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134 | actual = read(data->dev, buf, size);
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135 | if (actual != size) {
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136 | if (actual < 0)
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137 | actual = 0;
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138 | retval = EXT2_ET_SHORT_READ;
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139 | goto error_out;
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140 | }
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141 | return 0;
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142 |
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143 | error_out:
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144 | memset((char *) buf+actual, 0, size-actual);
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145 | if (channel->read_error)
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146 | retval = (channel->read_error)(channel, block, count, buf,
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147 | size, actual, retval);
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148 | return retval;
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149 | }
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150 | #else /* NEED_BOUNCE_BUFFER */
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151 | /*
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152 | * Windows and FreeBSD block devices only allow sector alignment IO in offset and size
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153 | */
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154 | static errcode_t raw_read_blk(io_channel channel,
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155 | struct unix_private_data *data,
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156 | unsigned long block,
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157 | int count, void *buf)
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158 | {
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159 | errcode_t retval;
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160 | size_t size, alignsize, fragment;
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161 | ext2_loff_t location;
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162 | int total = 0, actual;
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163 | #define BLOCKALIGN 512
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164 | char sector[BLOCKALIGN];
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165 |
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166 | size = (count < 0) ? -count : count * channel->block_size;
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167 | location = ((ext2_loff_t) block * channel->block_size) + data->offset;
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168 | #ifdef DEBUG
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169 | printf("count=%d, size=%d, block=%d, blk_size=%d, location=%lx\n",
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170 | count, size, block, channel->block_size, location);
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171 | #endif
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172 | if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
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173 | retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
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174 | goto error_out;
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175 | }
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176 | fragment = size % BLOCKALIGN;
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177 | alignsize = size - fragment;
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178 | if (alignsize) {
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179 | actual = read(data->dev, buf, alignsize);
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180 | if (actual != alignsize)
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181 | goto short_read;
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182 | }
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183 | if (fragment) {
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184 | actual = read(data->dev, sector, BLOCKALIGN);
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185 | if (actual != BLOCKALIGN)
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186 | goto short_read;
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187 | memcpy(buf+alignsize, sector, fragment);
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188 | }
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189 | return 0;
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190 |
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191 | short_read:
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192 | if (actual>0)
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193 | total += actual;
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194 | retval = EXT2_ET_SHORT_READ;
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195 |
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196 | error_out:
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197 | memset((char *) buf+total, 0, size-actual);
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198 | if (channel->read_error)
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199 | retval = (channel->read_error)(channel, block, count, buf,
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200 | size, actual, retval);
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201 | return retval;
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202 | }
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203 | #endif
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204 |
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205 | static errcode_t raw_write_blk(io_channel channel,
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206 | struct unix_private_data *data,
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207 | unsigned long block,
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208 | int count, const void *buf)
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209 | {
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210 | ssize_t size;
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211 | ext2_loff_t location;
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212 | int actual = 0;
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213 | errcode_t retval;
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214 |
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215 | if (count == 1)
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216 | size = channel->block_size;
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217 | else {
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218 | if (count < 0)
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219 | size = -count;
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220 | else
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221 | size = count * channel->block_size;
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222 | }
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223 |
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224 | location = ((ext2_loff_t) block * channel->block_size) + data->offset;
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225 | if (ext2fs_llseek(data->dev, location, SEEK_SET) != location) {
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226 | retval = errno ? errno : EXT2_ET_LLSEEK_FAILED;
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227 | goto error_out;
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228 | }
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229 |
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230 | actual = write(data->dev, buf, size);
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231 | if (actual != size) {
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232 | retval = EXT2_ET_SHORT_WRITE;
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233 | goto error_out;
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234 | }
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235 | return 0;
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236 |
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237 | error_out:
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238 | if (channel->write_error)
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239 | retval = (channel->write_error)(channel, block, count, buf,
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240 | size, actual, retval);
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241 | return retval;
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242 | }
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243 |
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244 |
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245 | /*
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246 | * Here we implement the cache functions
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247 | */
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248 |
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249 | /* Allocate the cache buffers */
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250 | static errcode_t alloc_cache(io_channel channel,
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251 | struct unix_private_data *data)
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252 | {
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253 | errcode_t retval;
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254 | struct unix_cache *cache;
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255 | int i;
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256 |
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257 | data->access_time = 0;
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258 | for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
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259 | cache->block = 0;
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260 | cache->access_time = 0;
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261 | cache->dirty = 0;
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262 | cache->in_use = 0;
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263 | if ((retval = ext2fs_get_mem(channel->block_size,
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264 | &cache->buf)))
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265 | return retval;
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266 | }
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267 | return 0;
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268 | }
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269 |
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270 | /* Free the cache buffers */
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271 | static void free_cache(struct unix_private_data *data)
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272 | {
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273 | struct unix_cache *cache;
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274 | int i;
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275 |
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276 | data->access_time = 0;
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277 | for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
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278 | cache->block = 0;
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279 | cache->access_time = 0;
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280 | cache->dirty = 0;
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281 | cache->in_use = 0;
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282 | ext2fs_free_mem(&cache->buf);
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283 | cache->buf = 0;
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284 | }
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285 | }
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286 |
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287 | #ifndef NO_IO_CACHE
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288 | /*
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289 | * Try to find a block in the cache. If the block is not found, and
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290 | * eldest is a non-zero pointer, then fill in eldest with the cache
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291 | * entry to that should be reused.
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292 | */
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293 | static struct unix_cache *find_cached_block(struct unix_private_data *data,
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294 | unsigned long block,
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295 | struct unix_cache **eldest)
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296 | {
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297 | struct unix_cache *cache, *unused_cache, *oldest_cache;
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298 | int i;
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299 |
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300 | unused_cache = oldest_cache = 0;
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301 | for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
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302 | if (!cache->in_use) {
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303 | if (!unused_cache)
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304 | unused_cache = cache;
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305 | continue;
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306 | }
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307 | if (cache->block == block) {
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308 | cache->access_time = ++data->access_time;
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309 | return cache;
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310 | }
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311 | if (!oldest_cache ||
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312 | (cache->access_time < oldest_cache->access_time))
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313 | oldest_cache = cache;
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314 | }
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315 | if (eldest)
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316 | *eldest = (unused_cache) ? unused_cache : oldest_cache;
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317 | return 0;
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318 | }
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319 |
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320 | /*
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321 | * Reuse a particular cache entry for another block.
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322 | */
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323 | static void reuse_cache(io_channel channel, struct unix_private_data *data,
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324 | struct unix_cache *cache, unsigned long block)
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325 | {
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326 | if (cache->dirty && cache->in_use)
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327 | raw_write_blk(channel, data, cache->block, 1, cache->buf);
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328 |
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329 | cache->in_use = 1;
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330 | cache->dirty = 0;
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331 | cache->block = block;
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332 | cache->access_time = ++data->access_time;
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333 | }
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334 |
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335 | /*
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336 | * Flush all of the blocks in the cache
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337 | */
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338 | static errcode_t flush_cached_blocks(io_channel channel,
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339 | struct unix_private_data *data,
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340 | int invalidate)
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341 |
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342 | {
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343 | struct unix_cache *cache;
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344 | errcode_t retval, retval2;
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345 | int i;
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346 |
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347 | retval2 = 0;
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348 | for (i=0, cache = data->cache; i < CACHE_SIZE; i++, cache++) {
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349 | if (!cache->in_use)
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350 | continue;
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351 |
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352 | if (invalidate)
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353 | cache->in_use = 0;
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354 |
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355 | if (!cache->dirty)
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356 | continue;
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357 |
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358 | retval = raw_write_blk(channel, data,
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359 | cache->block, 1, cache->buf);
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360 | if (retval)
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361 | retval2 = retval;
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362 | else
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363 | cache->dirty = 0;
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364 | }
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365 | return retval2;
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366 | }
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367 | #endif /* NO_IO_CACHE */
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368 |
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369 | static errcode_t unix_open(const char *name, int flags, io_channel *channel)
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370 | {
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371 | io_channel io = NULL;
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372 | struct unix_private_data *data = NULL;
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373 | errcode_t retval;
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374 | int open_flags;
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375 | struct stat st;
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376 | #ifdef __linux__
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377 | struct utsname ut;
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378 | #endif
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379 |
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380 | if (name == 0)
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381 | return EXT2_ET_BAD_DEVICE_NAME;
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382 | retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
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383 | if (retval)
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384 | return retval;
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385 | memset(io, 0, sizeof(struct struct_io_channel));
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386 | io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
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387 | retval = ext2fs_get_mem(sizeof(struct unix_private_data), &data);
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388 | if (retval)
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389 | goto cleanup;
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390 |
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391 | io->manager = unix_io_manager;
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392 | retval = ext2fs_get_mem(strlen(name)+1, &io->name);
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393 | if (retval)
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394 | goto cleanup;
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395 |
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396 | strcpy(io->name, name);
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397 | io->private_data = data;
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398 | io->block_size = 1024;
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399 | io->read_error = 0;
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400 | io->write_error = 0;
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401 | io->refcount = 1;
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402 |
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403 | memset(data, 0, sizeof(struct unix_private_data));
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404 | data->magic = EXT2_ET_MAGIC_UNIX_IO_CHANNEL;
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405 |
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406 | if ((retval = alloc_cache(io, data)))
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407 | goto cleanup;
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408 |
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409 | open_flags = (flags & IO_FLAG_RW) ? O_RDWR : O_RDONLY;
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410 | #ifdef CONFIG_LFS
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411 | data->dev = open64(io->name, open_flags);
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412 | #else
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413 | data->dev = open(io->name, open_flags);
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414 | #endif
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415 | if (data->dev < 0) {
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416 | retval = errno;
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417 | goto cleanup;
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418 | }
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419 |
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420 | #ifdef __linux__
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421 | #undef RLIM_INFINITY
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422 | #if (defined(__alpha__) || ((defined(__sparc__) || defined(__mips__)) && (SIZEOF_LONG == 4)))
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423 | #define RLIM_INFINITY ((unsigned long)(~0UL>>1))
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424 | #else
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425 | #define RLIM_INFINITY (~0UL)
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426 | #endif
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427 | /*
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428 | * Work around a bug in 2.4.10-2.4.18 kernels where writes to
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429 | * block devices are wrongly getting hit by the filesize
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430 | * limit. This workaround isn't perfect, since it won't work
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431 | * if glibc wasn't built against 2.2 header files. (Sigh.)
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432 | *
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433 | */
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434 | if ((flags & IO_FLAG_RW) &&
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435 | (uname(&ut) == 0) &&
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436 | ((ut.release[0] == '2') && (ut.release[1] == '.') &&
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437 | (ut.release[2] == '4') && (ut.release[3] == '.') &&
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438 | (ut.release[4] == '1') && (ut.release[5] >= '0') &&
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439 | (ut.release[5] < '8')) &&
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440 | (fstat(data->dev, &st) == 0) &&
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441 | (S_ISBLK(st.st_mode))) {
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442 | struct rlimit rlim;
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443 |
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444 | rlim.rlim_cur = rlim.rlim_max = (unsigned long) RLIM_INFINITY;
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445 | setrlimit(RLIMIT_FSIZE, &rlim);
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446 | getrlimit(RLIMIT_FSIZE, &rlim);
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447 | if (((unsigned long) rlim.rlim_cur) <
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448 | ((unsigned long) rlim.rlim_max)) {
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449 | rlim.rlim_cur = rlim.rlim_max;
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450 | setrlimit(RLIMIT_FSIZE, &rlim);
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451 | }
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452 | }
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453 | #endif
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454 | *channel = io;
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455 | return 0;
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456 |
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457 | cleanup:
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458 | if (data) {
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459 | free_cache(data);
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460 | ext2fs_free_mem(&data);
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461 | }
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462 | ext2fs_free_mem(&io);
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463 | return retval;
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464 | }
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465 |
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466 | static errcode_t unix_close(io_channel channel)
|
---|
467 | {
|
---|
468 | struct unix_private_data *data;
|
---|
469 | errcode_t retval = 0;
|
---|
470 |
|
---|
471 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
|
---|
472 | data = (struct unix_private_data *) channel->private_data;
|
---|
473 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
|
---|
474 |
|
---|
475 | if (--channel->refcount > 0)
|
---|
476 | return 0;
|
---|
477 |
|
---|
478 | #ifndef NO_IO_CACHE
|
---|
479 | retval = flush_cached_blocks(channel, data, 0);
|
---|
480 | #endif
|
---|
481 |
|
---|
482 | if (close(data->dev) < 0)
|
---|
483 | retval = errno;
|
---|
484 | free_cache(data);
|
---|
485 |
|
---|
486 | ext2fs_free_mem(&channel->private_data);
|
---|
487 | ext2fs_free_mem(&channel->name);
|
---|
488 | ext2fs_free_mem(&channel);
|
---|
489 | return retval;
|
---|
490 | }
|
---|
491 |
|
---|
492 | static errcode_t unix_set_blksize(io_channel channel, int blksize)
|
---|
493 | {
|
---|
494 | struct unix_private_data *data;
|
---|
495 | errcode_t retval;
|
---|
496 |
|
---|
497 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
|
---|
498 | data = (struct unix_private_data *) channel->private_data;
|
---|
499 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
|
---|
500 |
|
---|
501 | if (channel->block_size != blksize) {
|
---|
502 | #ifndef NO_IO_CACHE
|
---|
503 | if ((retval = flush_cached_blocks(channel, data, 0)))
|
---|
504 | return retval;
|
---|
505 | #endif
|
---|
506 |
|
---|
507 | channel->block_size = blksize;
|
---|
508 | free_cache(data);
|
---|
509 | if ((retval = alloc_cache(channel, data)))
|
---|
510 | return retval;
|
---|
511 | }
|
---|
512 | return 0;
|
---|
513 | }
|
---|
514 |
|
---|
515 |
|
---|
516 | static errcode_t unix_read_blk(io_channel channel, unsigned long block,
|
---|
517 | int count, void *buf)
|
---|
518 | {
|
---|
519 | struct unix_private_data *data;
|
---|
520 | struct unix_cache *cache, *reuse[READ_DIRECT_SIZE];
|
---|
521 | errcode_t retval;
|
---|
522 | char *cp;
|
---|
523 | int i, j;
|
---|
524 |
|
---|
525 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
|
---|
526 | data = (struct unix_private_data *) channel->private_data;
|
---|
527 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
|
---|
528 |
|
---|
529 | #ifdef NO_IO_CACHE
|
---|
530 | return raw_read_blk(channel, data, block, count, buf);
|
---|
531 | #else
|
---|
532 | /*
|
---|
533 | * If we're doing an odd-sized read or a very large read,
|
---|
534 | * flush out the cache and then do a direct read.
|
---|
535 | */
|
---|
536 | if (count < 0 || count > WRITE_DIRECT_SIZE) {
|
---|
537 | if ((retval = flush_cached_blocks(channel, data, 0)))
|
---|
538 | return retval;
|
---|
539 | return raw_read_blk(channel, data, block, count, buf);
|
---|
540 | }
|
---|
541 |
|
---|
542 | cp = buf;
|
---|
543 | while (count > 0) {
|
---|
544 | /* If it's in the cache, use it! */
|
---|
545 | if ((cache = find_cached_block(data, block, &reuse[0]))) {
|
---|
546 | #ifdef DEBUG
|
---|
547 | printf("Using cached block %d\n", block);
|
---|
548 | #endif
|
---|
549 | memcpy(cp, cache->buf, channel->block_size);
|
---|
550 | count--;
|
---|
551 | block++;
|
---|
552 | cp += channel->block_size;
|
---|
553 | continue;
|
---|
554 | }
|
---|
555 | /*
|
---|
556 | * Find the number of uncached blocks so we can do a
|
---|
557 | * single read request
|
---|
558 | */
|
---|
559 | for (i=1; i < count; i++)
|
---|
560 | if (find_cached_block(data, block+i, &reuse[i]))
|
---|
561 | break;
|
---|
562 | #ifdef DEBUG
|
---|
563 | printf("Reading %d blocks starting at %d\n", i, block);
|
---|
564 | #endif
|
---|
565 | if ((retval = raw_read_blk(channel, data, block, i, cp)))
|
---|
566 | return retval;
|
---|
567 |
|
---|
568 | /* Save the results in the cache */
|
---|
569 | for (j=0; j < i; j++) {
|
---|
570 | count--;
|
---|
571 | cache = reuse[j];
|
---|
572 | reuse_cache(channel, data, cache, block++);
|
---|
573 | memcpy(cache->buf, cp, channel->block_size);
|
---|
574 | cp += channel->block_size;
|
---|
575 | }
|
---|
576 | }
|
---|
577 | return 0;
|
---|
578 | #endif /* NO_IO_CACHE */
|
---|
579 | }
|
---|
580 |
|
---|
581 | static errcode_t unix_write_blk(io_channel channel, unsigned long block,
|
---|
582 | int count, const void *buf)
|
---|
583 | {
|
---|
584 | struct unix_private_data *data;
|
---|
585 | struct unix_cache *cache, *reuse;
|
---|
586 | errcode_t retval = 0;
|
---|
587 | const char *cp;
|
---|
588 | int writethrough;
|
---|
589 |
|
---|
590 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
|
---|
591 | data = (struct unix_private_data *) channel->private_data;
|
---|
592 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
|
---|
593 |
|
---|
594 | #ifdef NO_IO_CACHE
|
---|
595 | return raw_write_blk(channel, data, block, count, buf);
|
---|
596 | #else
|
---|
597 | /*
|
---|
598 | * If we're doing an odd-sized write or a very large write,
|
---|
599 | * flush out the cache completely and then do a direct write.
|
---|
600 | */
|
---|
601 | if (count < 0 || count > WRITE_DIRECT_SIZE) {
|
---|
602 | if ((retval = flush_cached_blocks(channel, data, 1)))
|
---|
603 | return retval;
|
---|
604 | return raw_write_blk(channel, data, block, count, buf);
|
---|
605 | }
|
---|
606 |
|
---|
607 | /*
|
---|
608 | * For a moderate-sized multi-block write, first force a write
|
---|
609 | * if we're in write-through cache mode, and then fill the
|
---|
610 | * cache with the blocks.
|
---|
611 | */
|
---|
612 | writethrough = channel->flags & CHANNEL_FLAGS_WRITETHROUGH;
|
---|
613 | if (writethrough)
|
---|
614 | retval = raw_write_blk(channel, data, block, count, buf);
|
---|
615 |
|
---|
616 | cp = buf;
|
---|
617 | while (count > 0) {
|
---|
618 | cache = find_cached_block(data, block, &reuse);
|
---|
619 | if (!cache) {
|
---|
620 | cache = reuse;
|
---|
621 | reuse_cache(channel, data, cache, block);
|
---|
622 | }
|
---|
623 | memcpy(cache->buf, cp, channel->block_size);
|
---|
624 | cache->dirty = !writethrough;
|
---|
625 | count--;
|
---|
626 | block++;
|
---|
627 | cp += channel->block_size;
|
---|
628 | }
|
---|
629 | return retval;
|
---|
630 | #endif /* NO_IO_CACHE */
|
---|
631 | }
|
---|
632 |
|
---|
633 | static errcode_t unix_write_byte(io_channel channel, unsigned long offset,
|
---|
634 | int size, const void *buf)
|
---|
635 | {
|
---|
636 | struct unix_private_data *data;
|
---|
637 | errcode_t retval = 0;
|
---|
638 | ssize_t actual;
|
---|
639 |
|
---|
640 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
|
---|
641 | data = (struct unix_private_data *) channel->private_data;
|
---|
642 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
|
---|
643 |
|
---|
644 | #ifndef NO_IO_CACHE
|
---|
645 | /*
|
---|
646 | * Flush out the cache completely
|
---|
647 | */
|
---|
648 | if ((retval = flush_cached_blocks(channel, data, 1)))
|
---|
649 | return retval;
|
---|
650 | #endif
|
---|
651 |
|
---|
652 | if (lseek(data->dev, offset + data->offset, SEEK_SET) < 0)
|
---|
653 | return errno;
|
---|
654 |
|
---|
655 | actual = write(data->dev, buf, size);
|
---|
656 | if (actual != size)
|
---|
657 | return EXT2_ET_SHORT_WRITE;
|
---|
658 |
|
---|
659 | return 0;
|
---|
660 | }
|
---|
661 |
|
---|
662 | /*
|
---|
663 | * Flush data buffers to disk.
|
---|
664 | */
|
---|
665 | static errcode_t unix_flush(io_channel channel)
|
---|
666 | {
|
---|
667 | struct unix_private_data *data;
|
---|
668 | errcode_t retval = 0;
|
---|
669 |
|
---|
670 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
|
---|
671 | data = (struct unix_private_data *) channel->private_data;
|
---|
672 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
|
---|
673 |
|
---|
674 | #ifndef NO_IO_CACHE
|
---|
675 | retval = flush_cached_blocks(channel, data, 0);
|
---|
676 | #endif
|
---|
677 | fsync(data->dev);
|
---|
678 | return retval;
|
---|
679 | }
|
---|
680 |
|
---|
681 | static errcode_t unix_set_option(io_channel channel, const char *option,
|
---|
682 | const char *arg)
|
---|
683 | {
|
---|
684 | struct unix_private_data *data;
|
---|
685 | unsigned long tmp;
|
---|
686 | char *end;
|
---|
687 |
|
---|
688 | EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
|
---|
689 | data = (struct unix_private_data *) channel->private_data;
|
---|
690 | EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_UNIX_IO_CHANNEL);
|
---|
691 |
|
---|
692 | if (!strcmp(option, "offset")) {
|
---|
693 | if (!arg)
|
---|
694 | return EXT2_ET_INVALID_ARGUMENT;
|
---|
695 |
|
---|
696 | tmp = strtoul(arg, &end, 0);
|
---|
697 | if (*end)
|
---|
698 | return EXT2_ET_INVALID_ARGUMENT;
|
---|
699 | data->offset = tmp;
|
---|
700 | return 0;
|
---|
701 | }
|
---|
702 | return EXT2_ET_INVALID_ARGUMENT;
|
---|
703 | }
|
---|