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14
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1 /* |
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2 * YAFFS: Yet another FFS. A NAND-flash specific file system. |
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3 * |
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4 * yaffs_packedtags2.c: Tags packing for YAFFS2 |
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5 * |
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6 * Copyright (C) 2002 Aleph One Ltd. |
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7 * |
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8 * Created by Charles Manning <charles@aleph1.co.uk> |
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9 * |
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10 * |
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11 * This program is free software; you can redistribute it and/or |
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12 * modify it under the terms of the GNU Lesser General Public License |
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13 * version 2.1 as published by the Free Software Foundation. |
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14 */ |
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15 |
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6
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16 #include "yaffs_packedtags2.h" |
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17 #include "yportenv.h" |
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14
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18 #include "yaffs_tagsvalidity.h" |
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19 |
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20 |
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21 |
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22 // This code packs a set of extended tags into a binary structure for NAND storage |
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23 |
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24 // Some of the information is "extra" struff which can be packed in to speed scanning |
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25 // This is defined by having the EXTRA_HEADER_INFO_FLAG set. |
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26 |
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27 |
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28 // Extra flags applied to chunkId |
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29 |
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30 #define EXTRA_HEADER_INFO_FLAG 0x80000000 |
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31 #define EXTRA_SHRINK_FLAG 0x40000000 |
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32 #define EXTRA_SPARE_FLAGS 0x30000000 |
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33 |
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34 #define ALL_EXTRA_FLAGS 0xF0000000 |
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35 |
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36 |
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37 |
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38 // Also, the top 4 bits of the object Id are set to the object type. |
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39 #define EXTRA_OBJECT_TYPE_SHIFT (28) |
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40 #define EXTRA_OBJECT_TYPE_MASK ((0x0F) << EXTRA_OBJECT_TYPE_SHIFT) |
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41 |
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6
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42 |
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43 |
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7
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44 static void yaffs_DumpPackedTags2(const yaffs_PackedTags2 *pt) |
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45 { |
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46 T(YAFFS_TRACE_MTD,(TSTR("packed tags obj %d chunk %d byte %d seq %d"TENDSTR),pt->t.objectId,pt->t.chunkId,pt->t.byteCount,pt->t.sequenceNumber)); |
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47 } |
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6
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48 |
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7
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49 static void yaffs_DumpTags2(const yaffs_ExtendedTags *t) |
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50 { |
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51 T(YAFFS_TRACE_MTD,(TSTR("ext.tags eccres %d blkbad %d chused %d obj %d chunk%d byte %d del %d ser %d seq %d"TENDSTR), |
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52 t->eccResult, t->blockBad, t->chunkUsed, t->objectId, t->chunkId, t->byteCount, t->chunkDeleted, t->serialNumber, t->sequenceNumber)); |
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53 |
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54 } |
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55 |
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56 void yaffs_PackTags2(yaffs_PackedTags2 *pt, const yaffs_ExtendedTags *t) |
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6
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57 { |
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58 pt->t.chunkId = t->chunkId; |
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59 pt->t.sequenceNumber = t->sequenceNumber; |
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60 pt->t.byteCount = t->byteCount; |
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61 pt->t.objectId = t->objectId; |
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62 |
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63 if(t->chunkId == 0 && t->extraHeaderInfoAvailable) |
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64 { |
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65 // Store the extra header info instead |
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66 pt->t.chunkId = EXTRA_HEADER_INFO_FLAG | t->extraParentObjectId; // We save the parent object in the chunkId |
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67 if(t->extraIsShrinkHeader) |
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68 { |
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69 pt->t.chunkId |= EXTRA_SHRINK_FLAG; |
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70 } |
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71 |
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72 pt->t.objectId &= ~EXTRA_OBJECT_TYPE_MASK; |
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73 pt->t.objectId |= (t->extraObjectType << EXTRA_OBJECT_TYPE_SHIFT); |
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74 |
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75 if(t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK) |
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76 { |
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77 pt->t.byteCount = t->extraEquivalentObjectId; |
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78 } |
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79 else if(t->extraObjectType == YAFFS_OBJECT_TYPE_FILE) |
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80 { |
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81 pt->t.byteCount = t->extraFileLength; |
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82 } |
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83 else |
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84 { |
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85 pt->t.byteCount = 0; |
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86 } |
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87 } |
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88 |
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7
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89 yaffs_DumpPackedTags2(pt); |
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90 yaffs_DumpTags2(t); |
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91 |
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92 yaffs_ECCCalculateOther((unsigned char *)&pt->t,sizeof(yaffs_PackedTags2TagsPart),&pt->ecc); |
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93 |
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94 } |
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95 |
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14
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96 void yaffs_UnpackTags2(yaffs_ExtendedTags *t, yaffs_PackedTags2 *pt) |
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6
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97 { |
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98 |
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99 |
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100 memset(t,0,sizeof(yaffs_ExtendedTags)); |
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101 |
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102 yaffs_InitialiseTags(t); |
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103 |
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104 if(pt->t.sequenceNumber != 0xFFFFFFFF) |
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6
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105 { |
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106 // Page is in use |
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107 yaffs_ECCOther ecc; |
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108 yaffs_ECCCalculateOther((unsigned char *)&pt->t,sizeof(yaffs_PackedTags2TagsPart),&ecc); |
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109 t->eccResult = yaffs_ECCCorrectOther((unsigned char *)&pt->t,sizeof(yaffs_PackedTags2TagsPart),&pt->ecc,&ecc); |
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110 t->blockBad = 0; |
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111 t->chunkUsed = 1; |
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112 t->objectId = pt->t.objectId; |
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113 t->chunkId = pt->t.chunkId; |
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114 t->byteCount = pt->t.byteCount; |
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115 t->chunkDeleted = 0; |
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116 t->serialNumber = 0; |
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117 t->sequenceNumber = pt->t.sequenceNumber; |
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118 |
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119 // Do extra header info stuff |
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120 |
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121 if(pt->t.chunkId & EXTRA_HEADER_INFO_FLAG) |
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122 { |
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123 t->chunkId = 0; |
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124 t->byteCount = 0; |
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125 |
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126 t->extraHeaderInfoAvailable = 1; |
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127 t->extraParentObjectId = pt->t.chunkId & (~(ALL_EXTRA_FLAGS)); |
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128 t->extraIsShrinkHeader = (pt->t.chunkId & EXTRA_SHRINK_FLAG) ? 1 : 0; |
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129 t->extraObjectType = pt->t.objectId >> EXTRA_OBJECT_TYPE_SHIFT; |
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130 t->objectId &= ~EXTRA_OBJECT_TYPE_MASK; |
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131 |
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132 if(t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK) |
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133 { |
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134 t->extraEquivalentObjectId = pt->t.byteCount; |
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135 } |
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136 else |
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137 { |
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138 t->extraFileLength = pt->t.byteCount; |
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139 } |
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140 } |
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6
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141 } |
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7
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142 |
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143 yaffs_DumpPackedTags2(pt); |
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144 yaffs_DumpTags2(t); |
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145 |
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6
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146 } |
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147 |
