fs/yaffs2/yaffs_packedtags2.c

   1 /*
   2  * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
   3  *
   4  * Copyright (C) 2002-2007 Aleph One Ltd.
   5  *   for Toby Churchill Ltd and Brightstar Engineering
   6  *
   7  * Created by Charles Manning <charles@aleph1.co.uk>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #include "yaffs_packedtags2.h"
  15 #include "yportenv.h"
  16 #include "yaffs_tagsvalidity.h"
  17
  18 /* This code packs a set of extended tags into a binary structure for
  19  * NAND storage
  20  */
  21
  22 /* Some of the information is "extra" struff which can be packed in to
  23  * speed scanning
  24  * This is defined by having the EXTRA_HEADER_INFO_FLAG set.
  25  */
  26
  27 /* Extra flags applied to chunkId */
  28
  29 #define EXTRA_HEADER_INFO_FLAG  0x80000000
  30 #define EXTRA_SHRINK_FLAG       0x40000000
  31 #define EXTRA_SHADOWS_FLAG      0x20000000
  32 #define EXTRA_SPARE_FLAGS       0x10000000
  33
  34 #define ALL_EXTRA_FLAGS         0xF0000000
  35
  36 /* Also, the top 4 bits of the object Id are set to the object type. */
  37 #define EXTRA_OBJECT_TYPE_SHIFT (28)
  38 #define EXTRA_OBJECT_TYPE_MASK  ((0x0F) << EXTRA_OBJECT_TYPE_SHIFT)
  39
  40 #ifndef CONFIG_YAFFS_DOES_ECC
  41 #define YAFFS_IGNORE_TAGS_ECC 1
  42 #endif
  43
  44 static void yaffs_DumpPackedTags2TagsPart(const yaffs_PackedTags2TagsPart *ptt)
  45 {
  46         T(YAFFS_TRACE_MTD,
  47           (TSTR("packed tags obj %d chunk %d byte %d seq %d" TENDSTR),
  48            ptt->objectId, ptt->chunkId, ptt->byteCount,
  49            ptt->sequenceNumber));
  50 }
  51 static void yaffs_DumpPackedTags2(const yaffs_PackedTags2 *pt)
  52 {
  53         yaffs_DumpPackedTags2TagsPart(&pt->t);
  54 }
  55
  56 static void yaffs_DumpTags2(const yaffs_ExtendedTags *t)
  57 {
  58         T(YAFFS_TRACE_MTD,
  59           (TSTR
  60            ("ext.tags eccres %d blkbad %d chused %d obj %d chunk%d byte %d del %d ser %d seq %d"
  61             TENDSTR), t->eccResult, t->blockBad, t->chunkUsed, t->objectId,
  62            t->chunkId, t->byteCount, t->chunkDeleted, t->serialNumber,
  63            t->sequenceNumber));
  64
  65 }
  66
  67 void yaffs_PackTags2TagsPart(yaffs_PackedTags2TagsPart *ptt,
  68                 const yaffs_ExtendedTags *t)
  69 {
  70         ptt->chunkId = t->chunkId;
  71         ptt->sequenceNumber = t->sequenceNumber;
  72         ptt->byteCount = t->byteCount;
  73         ptt->objectId = t->objectId;
  74
  75         if (t->chunkId == 0 && t->extraHeaderInfoAvailable) {
  76                 /* Store the extra header info instead */
  77                 /* We save the parent object in the chunkId */
  78                 ptt->chunkId = EXTRA_HEADER_INFO_FLAG
  79                         | t->extraParentObjectId;
  80                 if (t->extraIsShrinkHeader)
  81                         ptt->chunkId |= EXTRA_SHRINK_FLAG;
  82                 if (t->extraShadows)
  83                         ptt->chunkId |= EXTRA_SHADOWS_FLAG;
  84
  85                 ptt->objectId &= ~EXTRA_OBJECT_TYPE_MASK;
  86                 ptt->objectId |=
  87                     (t->extraObjectType << EXTRA_OBJECT_TYPE_SHIFT);
  88
  89                 if (t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK)
  90                         ptt->byteCount = t->extraEquivalentObjectId;
  91                 else if (t->extraObjectType == YAFFS_OBJECT_TYPE_FILE)
  92                         ptt->byteCount = t->extraFileLength;
  93                 else
  94                         ptt->byteCount = 0;
  95         }
  96
  97         yaffs_DumpPackedTags2TagsPart(ptt);
  98         yaffs_DumpTags2(t);
  99 }
 100
 101
 102 void yaffs_PackTags2(yaffs_PackedTags2 *pt, const yaffs_ExtendedTags *t)
 103 {
 104         yaffs_PackTags2TagsPart(&pt->t, t);
 105
 106 #ifndef YAFFS_IGNORE_TAGS_ECC
 107         {
 108                 yaffs_ECCCalculateOther((unsigned char *)&pt->t,
 109                                         sizeof(yaffs_PackedTags2TagsPart),
 110                                         &pt->ecc);
 111         }
 112 #endif
 113 }
 114
 115
 116 void yaffs_UnpackTags2TagsPart(yaffs_ExtendedTags *t,
 117                 yaffs_PackedTags2TagsPart *ptt)
 118 {
 119
 120         memset(t, 0, sizeof(yaffs_ExtendedTags));
 121
 122         yaffs_InitialiseTags(t);
 123
 124         if (ptt->sequenceNumber != 0xFFFFFFFF) {
 125                 t->blockBad = 0;
 126                 t->chunkUsed = 1;
 127                 t->objectId = ptt->objectId;
 128                 t->chunkId = ptt->chunkId;
 129                 t->byteCount = ptt->byteCount;
 130                 t->chunkDeleted = 0;
 131                 t->serialNumber = 0;
 132                 t->sequenceNumber = ptt->sequenceNumber;
 133
 134                 /* Do extra header info stuff */
 135
 136                 if (ptt->chunkId & EXTRA_HEADER_INFO_FLAG) {
 137                         t->chunkId = 0;
 138                         t->byteCount = 0;
 139
 140                         t->extraHeaderInfoAvailable = 1;
 141                         t->extraParentObjectId =
 142                             ptt->chunkId & (~(ALL_EXTRA_FLAGS));
 143                         t->extraIsShrinkHeader =
 144                             (ptt->chunkId & EXTRA_SHRINK_FLAG) ? 1 : 0;
 145                         t->extraShadows =
 146                             (ptt->chunkId & EXTRA_SHADOWS_FLAG) ? 1 : 0;
 147                         t->extraObjectType =
 148                             ptt->objectId >> EXTRA_OBJECT_TYPE_SHIFT;
 149                         t->objectId &= ~EXTRA_OBJECT_TYPE_MASK;
 150
 151                         if (t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK)
 152                                 t->extraEquivalentObjectId = ptt->byteCount;
 153                         else
 154                                 t->extraFileLength = ptt->byteCount;
 155                 }
 156         }
 157
 158         yaffs_DumpPackedTags2TagsPart(ptt);
 159         yaffs_DumpTags2(t);
 160
 161 }
 162
 163
 164 void yaffs_UnpackTags2(yaffs_ExtendedTags *t, yaffs_PackedTags2 *pt)
 165 {
 166
 167         yaffs_ECCResult eccResult = YAFFS_ECC_RESULT_NO_ERROR;
 168
 169         if (pt->t.sequenceNumber != 0xFFFFFFFF) {
 170                 /* Page is in use */
 171 #ifndef YAFFS_IGNORE_TAGS_ECC
 172                 {
 173                         yaffs_ECCOther ecc;
 174                         int result;
 175                         yaffs_ECCCalculateOther((unsigned char *)&pt->t,
 176                                                 sizeof
 177                                                 (yaffs_PackedTags2TagsPart),
 178                                                 &ecc);
 179                         result =
 180                             yaffs_ECCCorrectOther((unsigned char *)&pt->t,
 181                                                   sizeof
 182                                                   (yaffs_PackedTags2TagsPart),
 183                                                   &pt->ecc, &ecc);
 184                         switch (result) {
 185                         case 0:
 186                                 eccResult = YAFFS_ECC_RESULT_NO_ERROR;
 187                                 break;
 188                         case 1:
 189                                 eccResult = YAFFS_ECC_RESULT_FIXED;
 190                                 break;
 191                         case -1:
 192                                 eccResult = YAFFS_ECC_RESULT_UNFIXED;
 193                                 break;
 194                         default:
 195                                 eccResult = YAFFS_ECC_RESULT_UNKNOWN;
 196                         }
 197                 }
 198 #endif
 199         }
 200
 201         yaffs_UnpackTags2TagsPart(t, &pt->t);
 202
 203         t->eccResult = eccResult;
 204
 205         yaffs_DumpPackedTags2(pt);
 206         yaffs_DumpTags2(t);
 207
 208 }
 209