1 | /* |
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2 | * Copyright (c) 2012 embedded brains GmbH. All rights reserved. |
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3 | * |
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4 | * embedded brains GmbH |
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5 | * Obere Lagerstr. 30 |
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6 | * 82178 Puchheim |
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7 | * Germany |
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8 | * <rtems@embedded-brains.de> |
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9 | * |
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10 | * The license and distribution terms for this file may be |
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11 | * found in the file LICENSE in this distribution or at |
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12 | * http://www.rtems.com/license/LICENSE. |
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13 | */ |
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14 | |
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15 | #if HAVE_CONFIG_H |
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16 | #include "config.h" |
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17 | #endif |
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18 | |
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19 | #define __RTEMS_VIOLATE_KERNEL_VISIBILITY__ |
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20 | |
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21 | #include <stdlib.h> |
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22 | |
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23 | #include <rtems/libio_.h> |
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24 | #include <rtems/score/thread.h> |
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25 | |
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26 | static rtems_filesystem_global_location_t *deferred_released_global_locations; |
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27 | |
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28 | rtems_filesystem_location_info_t *rtems_filesystem_location_copy( |
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29 | rtems_filesystem_location_info_t *dst, |
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30 | const rtems_filesystem_location_info_t *src |
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31 | ) |
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32 | { |
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33 | dst->node_access = src->node_access; |
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34 | dst->node_access_2 = src->node_access_2; |
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35 | dst->handlers = src->handlers; |
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36 | dst->mt_entry = src->mt_entry; |
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37 | rtems_filesystem_location_add_to_mt_entry(dst); |
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38 | |
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39 | return dst; |
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40 | } |
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41 | |
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42 | void rtems_filesystem_location_detach( |
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43 | rtems_filesystem_location_info_t *detach |
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44 | ) |
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45 | { |
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46 | rtems_filesystem_location_free(detach); |
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47 | rtems_filesystem_location_initialize_to_null(detach); |
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48 | } |
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49 | |
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50 | void rtems_filesystem_location_copy_and_detach( |
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51 | rtems_filesystem_location_info_t *copy, |
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52 | rtems_filesystem_location_info_t *detach |
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53 | ) |
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54 | { |
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55 | rtems_filesystem_location_copy(copy, detach); |
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56 | rtems_filesystem_location_remove_from_mt_entry(detach); |
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57 | rtems_filesystem_location_initialize_to_null(detach); |
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58 | } |
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59 | |
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60 | rtems_filesystem_global_location_t *rtems_filesystem_location_transform_to_global( |
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61 | rtems_filesystem_location_info_t *loc |
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62 | ) |
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63 | { |
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64 | rtems_filesystem_global_location_t *global_loc = malloc(sizeof(*global_loc)); |
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65 | |
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66 | if (global_loc != NULL) { |
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67 | global_loc->reference_count = 1; |
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68 | global_loc->deferred_released_next = NULL; |
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69 | global_loc->deferred_released_count = 0; |
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70 | rtems_filesystem_location_copy(&global_loc->location, loc); |
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71 | rtems_filesystem_location_remove_from_mt_entry(loc); |
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72 | } else { |
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73 | rtems_filesystem_location_free(loc); |
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74 | global_loc = rtems_filesystem_global_location_obtain_null(); |
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75 | errno = ENOMEM; |
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76 | } |
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77 | |
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78 | return global_loc; |
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79 | } |
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80 | |
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81 | void rtems_filesystem_global_location_assign( |
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82 | rtems_filesystem_global_location_t **lhs_global_loc_ptr, |
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83 | rtems_filesystem_global_location_t *rhs_global_loc |
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84 | ) |
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85 | { |
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86 | rtems_filesystem_mt_entry_declare_lock_context(lock_context); |
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87 | rtems_filesystem_global_location_t *lhs_global_loc; |
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88 | |
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89 | rtems_filesystem_mt_entry_lock(lock_context); |
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90 | lhs_global_loc = *lhs_global_loc_ptr; |
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91 | *lhs_global_loc_ptr = rhs_global_loc; |
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92 | rtems_filesystem_mt_entry_unlock(lock_context); |
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93 | |
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94 | rtems_filesystem_global_location_release(lhs_global_loc); |
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95 | } |
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96 | |
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97 | static void release_with_count( |
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98 | rtems_filesystem_global_location_t *global_loc, |
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99 | int count |
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100 | ) |
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101 | { |
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102 | rtems_filesystem_mount_table_entry_t *mt_entry = |
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103 | global_loc->location.mt_entry; |
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104 | rtems_filesystem_mt_entry_declare_lock_context(lock_context); |
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105 | bool do_free; |
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106 | bool do_unmount; |
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107 | |
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108 | rtems_filesystem_mt_entry_lock(lock_context); |
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109 | global_loc->reference_count -= count; |
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110 | do_free = global_loc->reference_count == 0; |
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111 | do_unmount = rtems_filesystem_is_ready_for_unmount(mt_entry); |
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112 | rtems_filesystem_mt_entry_unlock(lock_context); |
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113 | |
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114 | if (do_free) { |
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115 | rtems_filesystem_location_free(&global_loc->location); |
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116 | free(global_loc); |
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117 | } |
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118 | |
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119 | if (do_unmount) { |
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120 | rtems_filesystem_do_unmount(mt_entry); |
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121 | } |
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122 | } |
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123 | |
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124 | static void deferred_release(void) |
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125 | { |
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126 | rtems_filesystem_global_location_t *current = NULL; |
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127 | |
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128 | do { |
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129 | int count = 0; |
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130 | |
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131 | _Thread_Disable_dispatch(); |
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132 | current = deferred_released_global_locations; |
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133 | if (current != NULL) { |
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134 | deferred_released_global_locations = current->deferred_released_next; |
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135 | count = current->deferred_released_count; |
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136 | current->deferred_released_next = NULL; |
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137 | current->deferred_released_count = 0; |
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138 | } |
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139 | _Thread_Enable_dispatch(); |
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140 | |
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141 | if (current != NULL) { |
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142 | release_with_count(current, count); |
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143 | } |
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144 | } while (current != NULL); |
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145 | } |
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146 | |
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147 | rtems_filesystem_global_location_t *rtems_filesystem_global_location_obtain( |
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148 | rtems_filesystem_global_location_t *const *global_loc_ptr |
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149 | ) |
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150 | { |
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151 | rtems_filesystem_mt_entry_declare_lock_context(lock_context); |
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152 | rtems_filesystem_global_location_t *global_loc; |
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153 | |
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154 | if (deferred_released_global_locations != NULL) { |
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155 | deferred_release(); |
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156 | } |
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157 | |
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158 | rtems_filesystem_mt_entry_lock(lock_context); |
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159 | global_loc = *global_loc_ptr; |
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160 | if (global_loc == NULL || !global_loc->location.mt_entry->mounted) { |
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161 | global_loc = &rtems_filesystem_global_location_null; |
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162 | errno = ENXIO; |
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163 | } |
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164 | ++global_loc->reference_count; |
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165 | rtems_filesystem_mt_entry_unlock(lock_context); |
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166 | |
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167 | return global_loc; |
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168 | } |
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169 | |
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170 | void rtems_filesystem_global_location_release( |
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171 | rtems_filesystem_global_location_t *global_loc |
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172 | ) |
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173 | { |
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174 | if (!_Thread_Dispatch_in_critical_section()) { |
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175 | release_with_count(global_loc, 1); |
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176 | } else { |
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177 | if (global_loc->deferred_released_count == 0) { |
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178 | rtems_filesystem_global_location_t *head = |
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179 | deferred_released_global_locations; |
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180 | |
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181 | global_loc->deferred_released_count = 1; |
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182 | global_loc->deferred_released_next = head; |
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183 | deferred_released_global_locations = global_loc; |
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184 | } else { |
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185 | ++global_loc->deferred_released_count; |
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186 | } |
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187 | } |
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188 | } |
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189 | |
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190 | void rtems_filesystem_location_remove_from_mt_entry( |
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191 | rtems_filesystem_location_info_t *loc |
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192 | ) |
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193 | { |
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194 | rtems_filesystem_mt_entry_declare_lock_context(lock_context); |
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195 | bool do_unmount; |
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196 | |
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197 | rtems_filesystem_mt_entry_lock(lock_context); |
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198 | rtems_chain_extract_unprotected(&loc->mt_entry_node); |
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199 | do_unmount = rtems_filesystem_is_ready_for_unmount(loc->mt_entry); |
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200 | rtems_filesystem_mt_entry_unlock(lock_context); |
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201 | |
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202 | if (do_unmount) { |
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203 | rtems_filesystem_do_unmount(loc->mt_entry); |
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204 | } |
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205 | } |
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206 | |
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207 | void rtems_filesystem_do_unmount( |
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208 | rtems_filesystem_mount_table_entry_t *mt_entry |
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209 | ) |
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210 | { |
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211 | rtems_filesystem_mt_lock(); |
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212 | rtems_chain_extract_unprotected(&mt_entry->mt_node); |
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213 | rtems_filesystem_mt_unlock(); |
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214 | rtems_filesystem_global_location_release(mt_entry->mt_point_node); |
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215 | (*mt_entry->ops->fsunmount_me_h)(mt_entry); |
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216 | free(mt_entry); |
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217 | } |
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