1 | /* |
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2 | * COPYRIGHT (c) 2010 Chris Johns <chrisj@rtems.org> |
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3 | * |
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4 | * The license and distribution terms for this file may be |
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5 | * found in the file LICENSE in this distribution or at |
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6 | * http://www.rtems.com/license/LICENSE. |
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7 | * |
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8 | * $Id$ |
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9 | */ |
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10 | /** |
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11 | * @file |
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12 | * |
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13 | * @ingroup rtems-rfs |
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14 | * |
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15 | * RTEMS File Systems Buffer Management. |
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16 | * |
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17 | * These functions map blocks to the media interface layers. |
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18 | */ |
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19 | |
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20 | #if !defined (_RTEMS_RFS_BUFFER_H_) |
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21 | #define _RTEMS_RFS_BUFFER_H_ |
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22 | |
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23 | #include <errno.h> |
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24 | |
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25 | #include <rtems/rfs/rtems-rfs-file-system-fwd.h> |
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26 | #include <rtems/rfs/rtems-rfs-trace.h> |
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27 | |
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28 | /** |
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29 | * Define the method used to interface to the buffers. It can be libblock or |
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30 | * device I/O. The libblock interface is to the RTEMS cache and block devices |
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31 | * and device I/O accesses the media via a device file handle. |
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32 | */ |
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33 | #if defined (__rtems__) |
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34 | #define RTEMS_RFS_USE_LIBBLOCK 1 |
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35 | #endif |
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36 | |
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37 | /** |
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38 | * The RTEMS RFS I/O Layering. |
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39 | */ |
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40 | #if RTEMS_RFS_USE_LIBBLOCK |
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41 | #include <rtems/bdbuf.h> |
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42 | #include <rtems/error.h> |
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43 | |
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44 | typedef rtems_blkdev_bnum rtems_rfs_buffer_block; |
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45 | typedef rtems_bdbuf_buffer rtems_rfs_buffer; |
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46 | #define rtems_rfs_buffer_io_request rtems_rfs_buffer_bdbuf_request |
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47 | #define rtems_rfs_buffer_io_release rtems_rfs_buffer_bdbuf_release |
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48 | |
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49 | /** |
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50 | * Request a buffer from the RTEMS libblock BD buffer cache. |
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51 | */ |
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52 | int rtems_rfs_buffer_bdbuf_request (rtems_rfs_file_system* fs, |
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53 | rtems_rfs_buffer_block block, |
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54 | bool read, |
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55 | rtems_rfs_buffer** buffer); |
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56 | /** |
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57 | * Release a buffer to the RTEMS libblock BD buffer cache. |
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58 | */ |
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59 | int rtems_rfs_buffer_bdbuf_release (rtems_rfs_buffer* handle, |
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60 | bool modified); |
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61 | #else /* Device I/O */ |
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62 | typedef uint32_t rtems_rfs_buffer_block; |
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63 | typedef struct _rtems_rfs_buffer |
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64 | { |
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65 | rtems_chain_node link; |
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66 | rtems_rfs_buffer_block user; |
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67 | void* buffer; |
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68 | size_t size; |
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69 | uint32_t references; |
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70 | } rtems_rfs_buffer; |
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71 | #define rtems_rfs_buffer_io_request rtems_rfs_buffer_devceio_request |
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72 | #define rtems_rfs_buffer_io_release rtems_rfs_uffer_deviceio_release |
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73 | |
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74 | /** |
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75 | * Request a buffer from the device I/O. |
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76 | */ |
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77 | int rtems_rfs_buffer_deviceio_request (rtems_rfs_file_system* fs, |
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78 | rtems_rfs_buffer_block block, |
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79 | bool read, |
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80 | rtems_rfs_buffer* buffer); |
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81 | /** |
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82 | * Release a buffer to the RTEMS libblock BD buffer cache. |
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83 | */ |
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84 | int rtems_rfs_buffer_deviceio_release (rtems_rfs_buffer* handle, |
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85 | bool modified); |
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86 | #endif |
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87 | |
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88 | /** |
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89 | * RFS Buffer handle. |
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90 | */ |
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91 | typedef struct rtems_rfs_buffer_handle_t |
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92 | { |
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93 | /** |
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94 | * Has the buffer been modifed? |
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95 | */ |
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96 | bool dirty; |
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97 | |
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98 | /** |
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99 | * Block number. The lower layer block number may be absolute and we maybe |
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100 | * relative to an offset in the disk so hold locally. |
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101 | */ |
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102 | rtems_rfs_buffer_block bnum; |
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103 | |
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104 | /** |
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105 | * Reference the buffer descriptor. |
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106 | */ |
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107 | rtems_rfs_buffer* buffer; |
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108 | |
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109 | } rtems_rfs_buffer_handle; |
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110 | |
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111 | /** |
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112 | * The buffer linkage. |
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113 | */ |
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114 | #define rtems_rfs_buffer_link(_h) (&(_h)->buffer->link) |
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115 | |
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116 | /** |
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117 | * Return the start of the data area of the buffer given a handle. |
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118 | */ |
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119 | #define rtems_rfs_buffer_data(_h) ((void*)((_h)->buffer->buffer)) |
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120 | |
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121 | /** |
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122 | * Return the size of the buffer given a handle. |
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123 | */ |
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124 | #define rtems_rfs_buffer_size(_h) ((_h)->buffer->size) |
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125 | |
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126 | /** |
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127 | * Return the block number. |
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128 | */ |
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129 | #define rtems_rfs_buffer_bnum(_h) ((_h)->bnum) |
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130 | |
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131 | /** |
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132 | * Return the buffer dirty status. |
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133 | */ |
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134 | #define rtems_rfs_buffer_dirty(_h) ((_h)->dirty) |
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135 | |
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136 | /** |
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137 | * Does the handle have a valid block attached ? |
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138 | */ |
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139 | #define rtems_rfs_buffer_handle_has_block(_h) ((_h)->buffer ? true : false) |
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140 | |
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141 | /** |
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142 | * Mark the buffer as dirty. |
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143 | */ |
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144 | #define rtems_rfs_buffer_mark_dirty(_h) ((_h)->dirty = true) |
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145 | |
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146 | /** |
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147 | * Return the reference count. |
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148 | */ |
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149 | #define rtems_rfs_buffer_refs(_h) ((_h)->buffer->references) |
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150 | |
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151 | /** |
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152 | * Increment the reference count. |
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153 | */ |
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154 | #define rtems_rfs_buffer_refs_up(_h) ((_h)->buffer->references += 1) |
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155 | |
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156 | /** |
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157 | * Decrement the reference count. |
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158 | */ |
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159 | #define rtems_rfs_buffer_refs_down(_h) ((_h)->buffer->references -= 1) |
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160 | |
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161 | /** |
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162 | * Request a buffer. The buffer can be filled with data from the media (read == |
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163 | * true) or you can request a buffer to fill with data. |
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164 | * |
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165 | * @param fs The file system data. |
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166 | * @param handle The handle the requested buffer is attached to. |
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167 | * @param block The block number. |
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168 | * @param read Read the data from the disk. |
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169 | * @return int The error number (errno). No error if 0. |
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170 | */ |
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171 | int rtems_rfs_buffer_handle_request (rtems_rfs_file_system* fs, |
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172 | rtems_rfs_buffer_handle* handle, |
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173 | rtems_rfs_buffer_block block, |
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174 | bool read); |
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175 | |
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176 | /** |
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177 | * Release a buffer. If the buffer is dirty the buffer is written to disk. The |
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178 | * result does not indicate if the data was successfully written to the disk as |
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179 | * this operation may be performed in asynchronously to this release. |
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180 | * |
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181 | * @param fs The file system data. |
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182 | * @param handle The handle the requested buffer is attached to. |
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183 | * @return int The error number (errno). No error if 0. |
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184 | */ |
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185 | int rtems_rfs_buffer_handle_release (rtems_rfs_file_system* fs, |
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186 | rtems_rfs_buffer_handle* handle); |
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187 | |
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188 | /** |
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189 | * Reset a handle. |
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190 | * |
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191 | * @param fs The file system data. |
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192 | * @param handle The buffer handle to reset. |
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193 | * @return int The error number (errno). No error if 0. |
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194 | */ |
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195 | static inline int |
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196 | rtems_rfs_buffer_handle_reset (rtems_rfs_buffer_handle* handle) |
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197 | { |
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198 | handle->dirty = false; |
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199 | handle->bnum = 0; |
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200 | handle->buffer = NULL; |
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201 | return 0; |
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202 | } |
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203 | |
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204 | /** |
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205 | * Open a handle. |
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206 | * |
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207 | * @param fs The file system data. |
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208 | * @param handle The buffer handle to open. |
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209 | * @return int The error number (errno). No error if 0. |
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210 | */ |
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211 | static inline int |
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212 | rtems_rfs_buffer_handle_open (rtems_rfs_file_system* fs, |
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213 | rtems_rfs_buffer_handle* handle) |
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214 | { |
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215 | rtems_rfs_buffer_handle_reset (handle); |
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216 | return 0; |
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217 | } |
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218 | |
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219 | /** |
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220 | * Close a handle. |
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221 | * |
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222 | * @param fs The file system data. |
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223 | * @param handle The buffer handle to close. |
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224 | * @return int The error number (errno). No error if 0. |
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225 | */ |
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226 | static inline int |
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227 | rtems_rfs_buffer_handle_close (rtems_rfs_file_system* fs, |
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228 | rtems_rfs_buffer_handle* handle) |
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229 | { |
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230 | rtems_rfs_buffer_handle_release (fs, handle); |
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231 | return 0; |
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232 | } |
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233 | |
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234 | /** |
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235 | * Open the buffer interface. |
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236 | * |
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237 | * @param name The device name to the media. |
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238 | * @param fs Pointer to the file system data. |
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239 | * @return int The error number (errno). No error if 0. |
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240 | */ |
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241 | int rtems_rfs_buffer_open (const char* name, rtems_rfs_file_system* fs); |
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242 | |
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243 | /** |
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244 | * Close the buffer interface. |
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245 | * |
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246 | * @param fs Pointer to the file system data. |
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247 | * @return int The error number (errno). No error if 0. |
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248 | */ |
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249 | int rtems_rfs_buffer_close (rtems_rfs_file_system* fs); |
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250 | |
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251 | /** |
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252 | * Sync all buffers to the media. |
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253 | * |
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254 | * @param fs Pointer to the file system data. |
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255 | * @return int The error number (errno). No error if 0. |
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256 | */ |
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257 | int rtems_rfs_buffer_sync (rtems_rfs_file_system* fs); |
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258 | |
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259 | /** |
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260 | * Set the block size of the device. |
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261 | * |
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262 | * @param fs Pointer to the file system data. |
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263 | * @param size The new block size. |
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264 | * @return int The error number (errno). No error if 0. |
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265 | */ |
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266 | int rtems_rfs_buffer_setblksize (rtems_rfs_file_system* fs, size_t size); |
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267 | |
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268 | /** |
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269 | * Release any chained buffers. |
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270 | * |
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271 | * @param fs The file system data. |
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272 | * @return int The error number (errno). No error if 0. |
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273 | */ |
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274 | int rtems_rfs_buffers_release (rtems_rfs_file_system* fs); |
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275 | |
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276 | #endif |
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