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 Routines. |
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16 | * |
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17 | */ |
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18 | |
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19 | #if HAVE_CONFIG_H |
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20 | #include "config.h" |
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21 | #endif |
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22 | |
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23 | #include <sys/stat.h> |
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24 | #include <inttypes.h> |
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25 | #include <errno.h> |
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26 | #include <fcntl.h> |
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27 | |
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28 | #include <rtems/rfs/rtems-rfs-buffer.h> |
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29 | #include <rtems/rfs/rtems-rfs-file-system.h> |
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30 | |
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31 | /** |
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32 | * Scan the chain for a buffer that matches the block number. |
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33 | * |
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34 | * @param chain The chain to scan. |
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35 | * @param count The number of items on the chain. |
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36 | * @param block The block number to find. |
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37 | * @return rtems_rfs_buffer* The buffer if found else NULL. |
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38 | */ |
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39 | static rtems_rfs_buffer* |
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40 | rtems_rfs_scan_chain (rtems_chain_control* chain, |
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41 | uint32_t* count, |
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42 | rtems_rfs_buffer_block block) |
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43 | { |
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44 | rtems_rfs_buffer* buffer; |
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45 | rtems_chain_node* node; |
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46 | |
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47 | node = rtems_chain_last (chain); |
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48 | |
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49 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CHAINS)) |
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50 | printf ("rtems-rfs: buffer-scan: count=%" PRIu32 ", block=%" PRIu32 ": ", *count, block); |
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51 | |
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52 | while (!rtems_chain_is_head (chain, node)) |
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53 | { |
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54 | buffer = (rtems_rfs_buffer*) node; |
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55 | |
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56 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CHAINS)) |
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57 | printf ("%" PRIuPTR " ", ((intptr_t) buffer->user)); |
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58 | |
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59 | if (((rtems_rfs_buffer_block) ((intptr_t)(buffer->user))) == block) |
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60 | { |
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61 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CHAINS)) |
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62 | printf (": found block=%" PRIuPTR "\n", |
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63 | ((intptr_t)(buffer->user))); |
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64 | |
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65 | (*count)--; |
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66 | rtems_chain_extract (node); |
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67 | rtems_chain_set_off_chain (node); |
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68 | return buffer; |
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69 | } |
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70 | node = rtems_chain_previous (node); |
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71 | } |
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72 | |
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73 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CHAINS)) |
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74 | printf (": not found\n"); |
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75 | |
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76 | return NULL; |
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77 | } |
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78 | |
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79 | int |
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80 | rtems_rfs_buffer_handle_request (rtems_rfs_file_system* fs, |
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81 | rtems_rfs_buffer_handle* handle, |
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82 | rtems_rfs_buffer_block block, |
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83 | bool read) |
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84 | { |
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85 | int rc; |
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86 | |
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87 | /* |
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88 | * If the handle has a buffer release it. This allows a handle to be reused |
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89 | * without needing to close then open it again. |
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90 | */ |
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91 | if (rtems_rfs_buffer_handle_has_block (handle)) |
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92 | { |
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93 | /* |
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94 | * Treat block 0 as special to handle the loading of the super block. |
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95 | */ |
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96 | if (block && (rtems_rfs_buffer_bnum (handle) == block)) |
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97 | return 0; |
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98 | |
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99 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_HANDLE_REQUEST)) |
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100 | printf ("rtems-rfs: buffer-request: handle has buffer: %" PRIu32 "\n", |
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101 | rtems_rfs_buffer_bnum (handle)); |
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102 | |
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103 | rc = rtems_rfs_buffer_handle_release (fs, handle); |
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104 | if (rc > 0) |
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105 | return rc; |
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106 | handle->dirty = false; |
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107 | handle->bnum = 0; |
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108 | } |
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109 | |
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110 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_HANDLE_REQUEST)) |
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111 | printf ("rtems-rfs: buffer-request: block=%" PRIu32 "\n", block); |
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112 | |
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113 | /* |
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114 | * First check to see if the buffer has already been requested and is |
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115 | * currently attached to a handle. If it is share the access. A buffer could |
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116 | * be shared where different parts of the block have separate functions. An |
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117 | * example is an inode block and the file system needs to handle 2 inodes in |
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118 | * the same block at the same time. |
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119 | */ |
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120 | if (fs->buffers_count) |
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121 | { |
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122 | /* |
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123 | * Check the active buffer list for shared buffers. |
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124 | */ |
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125 | handle->buffer = rtems_rfs_scan_chain (&fs->buffers, |
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126 | &fs->buffers_count, |
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127 | block); |
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128 | if (rtems_rfs_buffer_handle_has_block (handle) && |
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129 | rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_HANDLE_REQUEST)) |
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130 | printf ("rtems-rfs: buffer-request: buffer shared: refs: %d\n", |
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131 | rtems_rfs_buffer_refs (handle) + 1); |
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132 | } |
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133 | |
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134 | /* |
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135 | * If the buffer has not been found check the local cache of released |
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136 | * buffers. There are release and released modified lists to preserve the |
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137 | * state. |
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138 | */ |
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139 | if (!rtems_rfs_fs_no_local_cache (fs) && |
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140 | !rtems_rfs_buffer_handle_has_block (handle)) |
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141 | { |
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142 | /* |
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143 | * Check the local cache of released buffers. |
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144 | */ |
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145 | if (fs->release_count) |
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146 | handle->buffer = rtems_rfs_scan_chain (&fs->release, |
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147 | &fs->release_count, |
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148 | block); |
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149 | |
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150 | if (!rtems_rfs_buffer_handle_has_block (handle) && |
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151 | fs->release_modified_count) |
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152 | { |
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153 | handle->buffer = rtems_rfs_scan_chain (&fs->release_modified, |
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154 | &fs->release_modified_count, |
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155 | block); |
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156 | /* |
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157 | * If we found a buffer retain the dirty buffer state. |
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158 | */ |
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159 | if (rtems_rfs_buffer_handle_has_block (handle)) |
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160 | rtems_rfs_buffer_mark_dirty (handle); |
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161 | } |
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162 | } |
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163 | |
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164 | /* |
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165 | * If not located we request the buffer from the I/O layer. |
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166 | */ |
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167 | if (!rtems_rfs_buffer_handle_has_block (handle)) |
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168 | { |
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169 | rc = rtems_rfs_buffer_io_request (fs, block, read, &handle->buffer); |
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170 | |
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171 | rtems_chain_set_off_chain (rtems_rfs_buffer_link(handle)); |
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172 | |
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173 | if (rc > 0) |
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174 | { |
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175 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_HANDLE_REQUEST)) |
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176 | printf ("rtems-rfs: buffer-request: block=%" PRIu32 ": bdbuf-%s: %d: %s\n", |
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177 | block, read ? "read" : "get", rc, strerror (rc)); |
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178 | return rc; |
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179 | } |
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180 | } |
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181 | |
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182 | /* |
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183 | * Increase the reference count of the buffer. |
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184 | */ |
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185 | rtems_rfs_buffer_refs_up (handle); |
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186 | rtems_chain_append (&fs->buffers, rtems_rfs_buffer_link (handle)); |
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187 | fs->buffers_count++; |
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188 | |
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189 | handle->buffer->user = (void*) ((intptr_t) block); |
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190 | handle->bnum = block; |
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191 | |
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192 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_HANDLE_REQUEST)) |
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193 | printf ("rtems-rfs: buffer-request: block=%" PRIu32 " bdbuf-%s=%" PRIu32 " refs=%d\n", |
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194 | block, read ? "read" : "get", handle->buffer->block, |
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195 | handle->buffer->references); |
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196 | |
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197 | return 0; |
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198 | } |
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199 | |
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200 | int |
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201 | rtems_rfs_buffer_handle_release (rtems_rfs_file_system* fs, |
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202 | rtems_rfs_buffer_handle* handle) |
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203 | { |
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204 | int rc = 0; |
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205 | |
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206 | if (rtems_rfs_buffer_handle_has_block (handle)) |
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207 | { |
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208 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_HANDLE_RELEASE)) |
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209 | printf ("rtems-rfs: buffer-release: block=%" PRIu32 " %s refs=%d %s\n", |
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210 | rtems_rfs_buffer_bnum (handle), |
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211 | rtems_rfs_buffer_dirty (handle) ? "(dirty)" : "", |
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212 | rtems_rfs_buffer_refs (handle), |
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213 | rtems_rfs_buffer_refs (handle) == 0 ? "BAD REF COUNT" : ""); |
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214 | |
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215 | if (rtems_rfs_buffer_refs (handle) > 0) |
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216 | rtems_rfs_buffer_refs_down (handle); |
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217 | |
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218 | if (rtems_rfs_buffer_refs (handle) == 0) |
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219 | { |
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220 | rtems_chain_extract (rtems_rfs_buffer_link (handle)); |
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221 | fs->buffers_count--; |
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222 | |
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223 | if (rtems_rfs_fs_no_local_cache (fs)) |
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224 | { |
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225 | handle->buffer->user = (void*) 0; |
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226 | rc = rtems_rfs_buffer_io_release (handle->buffer, |
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227 | rtems_rfs_buffer_dirty (handle)); |
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228 | } |
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229 | else |
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230 | { |
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231 | /* |
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232 | * If the total number of held buffers is higher than the configured |
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233 | * value remove a buffer from the queue with the most buffers and |
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234 | * release. The buffers are held on the queues with the newest at the |
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235 | * head. |
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236 | * |
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237 | * This code stops a large series of transactions causing all the |
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238 | * buffers in the cache being held in queues of this file system. |
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239 | */ |
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240 | if ((fs->release_count + |
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241 | fs->release_modified_count) >= fs->max_held_buffers) |
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242 | { |
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243 | rtems_rfs_buffer* buffer; |
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244 | bool modified; |
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245 | |
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246 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_HANDLE_RELEASE)) |
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247 | printf ("rtems-rfs: buffer-release: local cache overflow:" |
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248 | " %" PRIu32 "\n", fs->release_count + fs->release_modified_count); |
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249 | |
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250 | if (fs->release_count > fs->release_modified_count) |
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251 | { |
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252 | buffer = (rtems_rfs_buffer*) rtems_chain_get (&fs->release); |
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253 | fs->release_count--; |
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254 | modified = false; |
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255 | } |
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256 | else |
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257 | { |
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258 | buffer = |
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259 | (rtems_rfs_buffer*) rtems_chain_get (&fs->release_modified); |
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260 | fs->release_modified_count--; |
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261 | modified = true; |
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262 | } |
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263 | buffer->user = (void*) 0; |
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264 | rc = rtems_rfs_buffer_io_release (buffer, modified); |
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265 | } |
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266 | |
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267 | if (rtems_rfs_buffer_dirty (handle)) |
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268 | { |
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269 | rtems_chain_append (&fs->release_modified, |
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270 | rtems_rfs_buffer_link (handle)); |
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271 | fs->release_modified_count++; |
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272 | } |
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273 | else |
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274 | { |
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275 | rtems_chain_append (&fs->release, rtems_rfs_buffer_link (handle)); |
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276 | fs->release_count++; |
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277 | } |
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278 | } |
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279 | } |
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280 | handle->buffer = NULL; |
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281 | } |
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282 | |
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283 | return rc; |
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284 | } |
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285 | |
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286 | int |
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287 | rtems_rfs_buffer_open (const char* name, rtems_rfs_file_system* fs) |
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288 | { |
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289 | struct stat st; |
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290 | #if RTEMS_RFS_USE_LIBBLOCK |
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291 | int rv; |
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292 | #endif |
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293 | |
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294 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_SYNC)) |
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295 | printf ("rtems-rfs: buffer-open: opening: %s\n", name); |
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296 | |
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297 | fs->device = open (name, O_RDWR); |
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298 | if (fs->device < 0) |
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299 | { |
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300 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_OPEN)) |
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301 | printf ("rtems-rfs: buffer-open: cannot open file\n"); |
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302 | return ENXIO; |
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303 | } |
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304 | |
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305 | if (fstat (fs->device, &st) < 0) |
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306 | { |
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307 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_OPEN)) |
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308 | printf ("rtems-rfs: buffer-open: stat '%s' failed: %s\n", |
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309 | name, strerror (errno)); |
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310 | return ENXIO; |
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311 | } |
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312 | |
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313 | #if RTEMS_RFS_USE_LIBBLOCK |
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314 | /* |
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315 | * Is the device a block device ? |
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316 | */ |
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317 | if (!S_ISBLK (st.st_mode)) |
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318 | { |
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319 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_OPEN)) |
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320 | printf ("rtems-rfs: buffer-open: '%s' is not a block device\n", name); |
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321 | return ENXIO; |
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322 | } |
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323 | |
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324 | /* |
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325 | * Check that device is registred as a block device and lock it. |
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326 | */ |
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327 | rv = rtems_disk_fd_get_disk_device (fs->device, &fs->disk); |
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328 | if (rv != 0) |
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329 | { |
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330 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_OPEN)) |
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331 | printf ("rtems-rfs: buffer-open: cannot obtain the disk\n"); |
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332 | return ENXIO; |
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333 | } |
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334 | #else |
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335 | fs->media_size = st.st_size; |
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336 | strcat (fs->name, name); |
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337 | #endif |
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338 | |
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339 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_SYNC)) |
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340 | printf ("rtems-rfs: buffer-open: blks=%" PRId32 ", blk-size=%" PRId32 "\n", |
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341 | rtems_rfs_fs_media_blocks (fs), |
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342 | rtems_rfs_fs_media_block_size (fs)); |
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343 | |
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344 | return 0; |
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345 | } |
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346 | |
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347 | int |
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348 | rtems_rfs_buffer_close (rtems_rfs_file_system* fs) |
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349 | { |
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350 | int rc = 0; |
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351 | |
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352 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CLOSE)) |
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353 | printf ("rtems-rfs: buffer-close: closing\n"); |
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354 | |
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355 | /* |
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356 | * Change the block size to the media device size. It will release and sync |
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357 | * all buffers. |
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358 | */ |
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359 | rc = rtems_rfs_buffer_setblksize (fs, rtems_rfs_fs_media_block_size (fs)); |
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360 | |
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361 | if ((rc > 0) && rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CLOSE)) |
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362 | printf ("rtems-rfs: buffer-close: set media block size failed: %d: %s\n", |
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363 | rc, strerror (rc)); |
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364 | |
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365 | if (close (fs->device) < 0) |
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366 | { |
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367 | rc = errno; |
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368 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CLOSE)) |
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369 | printf ("rtems-rfs: buffer-close: file close failed: %d: %s\n", |
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370 | rc, strerror (rc)); |
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371 | } |
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372 | |
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373 | return rc; |
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374 | } |
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375 | |
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376 | int |
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377 | rtems_rfs_buffer_sync (rtems_rfs_file_system* fs) |
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378 | { |
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379 | int result = 0; |
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380 | #if RTEMS_RFS_USE_LIBBLOCK |
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381 | rtems_status_code sc; |
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382 | #endif |
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383 | |
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384 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_SYNC)) |
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385 | printf ("rtems-rfs: buffer-sync: syncing\n"); |
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386 | |
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387 | /* |
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388 | * @todo Split in the separate files for each type. |
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389 | */ |
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390 | #if RTEMS_RFS_USE_LIBBLOCK |
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391 | sc = rtems_bdbuf_syncdev (rtems_rfs_fs_device (fs)); |
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392 | if (sc != RTEMS_SUCCESSFUL) |
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393 | { |
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394 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_SYNC)) |
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395 | printf ("rtems-rfs: buffer-sync: device sync failed: %s\n", |
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396 | rtems_status_text (sc)); |
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397 | result = EIO; |
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398 | } |
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399 | rtems_disk_release (fs->disk); |
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400 | #else |
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401 | if (fsync (fs->device) < 0) |
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402 | { |
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403 | result = errno; |
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404 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CLOSE)) |
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405 | printf ("rtems-rfs: buffer-sync: file sync failed: %d: %s\n", |
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406 | result, strerror (result)); |
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407 | } |
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408 | #endif |
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409 | return result; |
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410 | } |
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411 | |
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412 | int |
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413 | rtems_rfs_buffer_setblksize (rtems_rfs_file_system* fs, size_t size) |
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414 | { |
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415 | int rc; |
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416 | |
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417 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_SETBLKSIZE)) |
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418 | printf ("rtems-rfs: buffer-setblksize: block size: %zu\n", size); |
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419 | |
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420 | rc = rtems_rfs_buffers_release (fs); |
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421 | if ((rc > 0) && rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_SETBLKSIZE)) |
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422 | printf ("rtems-rfs: buffer-setblksize: buffer release failed: %d: %s\n", |
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423 | rc, strerror (rc)); |
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424 | |
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425 | rc = rtems_rfs_buffer_sync (fs); |
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426 | if ((rc > 0) && rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_SETBLKSIZE)) |
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427 | printf ("rtems-rfs: buffer-setblksize: device sync failed: %d: %s\n", |
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428 | rc, strerror (rc)); |
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429 | |
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430 | #if RTEMS_RFS_USE_LIBBLOCK |
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431 | rc = fs->disk->ioctl (fs->disk, RTEMS_BLKIO_SETBLKSIZE, &size); |
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432 | if (rc < 0) |
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433 | rc = errno; |
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434 | #endif |
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435 | return rc; |
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436 | } |
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437 | |
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438 | static int |
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439 | rtems_rfs_release_chain (rtems_chain_control* chain, |
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440 | uint32_t* count, |
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441 | bool modified) |
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442 | { |
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443 | rtems_rfs_buffer* buffer; |
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444 | int rrc = 0; |
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445 | int rc; |
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446 | |
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447 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_CHAINS)) |
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448 | printf ("rtems-rfs: release-chain: count=%" PRIu32 "\n", *count); |
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449 | |
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450 | while (!rtems_chain_is_empty (chain)) |
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451 | { |
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452 | buffer = (rtems_rfs_buffer*) rtems_chain_get (chain); |
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453 | (*count)--; |
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454 | |
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455 | buffer->user = (void*) 0; |
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456 | |
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457 | rc = rtems_rfs_buffer_io_release (buffer, modified); |
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458 | if ((rc > 0) && (rrc == 0)) |
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459 | rrc = rc; |
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460 | } |
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461 | return rrc; |
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462 | } |
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463 | |
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464 | int |
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465 | rtems_rfs_buffers_release (rtems_rfs_file_system* fs) |
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466 | { |
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467 | int rrc = 0; |
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468 | int rc; |
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469 | |
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470 | if (rtems_rfs_trace (RTEMS_RFS_TRACE_BUFFER_RELEASE)) |
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471 | printf ("rtems-rfs: buffers-release: active:%" PRIu32 " " |
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472 | "release:%" PRIu32 " release-modified:%" PRIu32 "\n", |
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473 | fs->buffers_count, fs->release_count, fs->release_modified_count); |
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474 | |
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475 | rc = rtems_rfs_release_chain (&fs->release, |
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476 | &fs->release_count, |
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477 | false); |
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478 | if ((rc > 0) && (rrc == 0)) |
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479 | rrc = rc; |
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480 | rc = rtems_rfs_release_chain (&fs->release_modified, |
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481 | &fs->release_modified_count, |
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482 | true); |
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483 | if ((rc > 0) && (rrc == 0)) |
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484 | rrc = rc; |
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485 | |
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486 | return rrc; |
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487 | } |
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