Add missing default value for some Kconfig's entries.
[yaffs2.git] / yaffs_packedtags2.c
index 97668dc..f4de18d 100644 (file)
@@ -1,5 +1,45 @@
+/*
+ * YAFFS: Yet another FFS. A NAND-flash specific file system. 
+ *
+ * yaffs_packedtags2.c: Tags packing for YAFFS2
+ *
+ * Copyright (C) 2002 Aleph One Ltd.
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ *
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
+ */
 #include "yaffs_packedtags2.h"
 #include "yportenv.h"
+#include "yaffs_tagsvalidity.h"
+
+
+
+// This code packs a set of extended tags into a binary structure for NAND storage
+
+// Some of the information is "extra" struff which can be packed in to speed scanning
+// This is defined by having the EXTRA_HEADER_INFO_FLAG set.
+
+
+// Extra flags applied to chunkId
+
+#define EXTRA_HEADER_INFO_FLAG 0x80000000
+#define EXTRA_SHRINK_FLAG      0x40000000
+#define EXTRA_SHADOWS_FLAG     0x20000000
+#define EXTRA_SPARE_FLAGS      0x10000000
+
+#define ALL_EXTRA_FLAGS                0xF0000000
+
+
+
+// Also, the top 4 bits of the object Id are set to the object type.
+#define EXTRA_OBJECT_TYPE_SHIFT (28)
+#define EXTRA_OBJECT_TYPE_MASK  ((0x0F) << EXTRA_OBJECT_TYPE_SHIFT)
+
 
 
 static void yaffs_DumpPackedTags2(const yaffs_PackedTags2 *pt)
@@ -21,28 +61,68 @@ void yaffs_PackTags2(yaffs_PackedTags2 *pt, const yaffs_ExtendedTags *t)
        pt->t.byteCount = t->byteCount;
        pt->t.objectId = t->objectId;
        
+       if(t->chunkId == 0 && t->extraHeaderInfoAvailable)
+       {
+               // Store the extra header info instead
+               pt->t.chunkId = EXTRA_HEADER_INFO_FLAG | t->extraParentObjectId; // We save the parent object in the chunkId
+               if(t->extraIsShrinkHeader) 
+               {
+                   pt->t.chunkId |= EXTRA_SHRINK_FLAG;
+               }
+               if(t->extraShadows) 
+               {
+                   pt->t.chunkId |= EXTRA_SHADOWS_FLAG;
+               }
+               
+               pt->t.objectId &= ~EXTRA_OBJECT_TYPE_MASK;
+               pt->t.objectId |= (t->extraObjectType << EXTRA_OBJECT_TYPE_SHIFT);
+                
+               if(t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK)
+               {
+                  pt->t.byteCount = t->extraEquivalentObjectId;
+               }
+               else if(t->extraObjectType == YAFFS_OBJECT_TYPE_FILE)
+               {
+                  pt->t.byteCount = t->extraFileLength;
+               }
+               else
+               {
+                  pt->t.byteCount = 0;
+               }
+       }
+       
        yaffs_DumpPackedTags2(pt);
        yaffs_DumpTags2(t);
        
-       yaffs_ECCCalculateOther((unsigned char *)&pt->t,sizeof(yaffs_PackedTags2TagsPart),&pt->ecc);
-       
+#ifndef YAFFS_IGNORE_TAGS_ECC
+       { 
+         yaffs_ECCCalculateOther((unsigned char *)&pt->t,sizeof(yaffs_PackedTags2TagsPart),&pt->ecc);
+       }
+#endif
 }
 
-void yaffs_UnpackTags2(yaffs_ExtendedTags *t, const yaffs_PackedTags2 *pt)
+void yaffs_UnpackTags2(yaffs_ExtendedTags *t, yaffs_PackedTags2 *pt)
 {
 
        
-       if(pt->t.sequenceNumber == 0xFFFFFFFF)
-       {
-               memset(t,0,sizeof(yaffs_ExtendedTags));
-               
-       }
-       else
+       memset(t,0,sizeof(yaffs_ExtendedTags));
+       
+       yaffs_InitialiseTags(t);
+       
+       if(pt->t.sequenceNumber != 0xFFFFFFFF)
        {
                // Page is in use
-               yaffs_ECCOther ecc;
-               yaffs_ECCCalculateOther((unsigned char *)&pt->t,sizeof(yaffs_PackedTags2TagsPart),&ecc);
-               t->eccResult = yaffs_ECCCorrectOther((unsigned char *)&pt->t,sizeof(yaffs_PackedTags2TagsPart),&pt->ecc,&ecc);
+#ifdef YAFFS_IGNORE_TAGS_ECC
+               {
+                       t->eccResult = 0;
+               }
+#else
+               {
+                       yaffs_ECCOther ecc;
+                       yaffs_ECCCalculateOther((unsigned char *)&pt->t,sizeof(yaffs_PackedTags2TagsPart),&ecc);
+                       t->eccResult = yaffs_ECCCorrectOther((unsigned char *)&pt->t,sizeof(yaffs_PackedTags2TagsPart),&pt->ecc,&ecc);
+               }
+#endif
                t->blockBad = 0;
                t->chunkUsed = 1;
                t->objectId = pt->t.objectId;
@@ -51,6 +131,30 @@ void yaffs_UnpackTags2(yaffs_ExtendedTags *t, const yaffs_PackedTags2 *pt)
                t->chunkDeleted = 0;
                t->serialNumber = 0;
                t->sequenceNumber = pt->t.sequenceNumber;
+               
+               // Do extra header info stuff
+               
+               if(pt->t.chunkId & EXTRA_HEADER_INFO_FLAG)
+               {
+                       t->chunkId = 0;
+                       t->byteCount = 0;
+                       
+                       t->extraHeaderInfoAvailable = 1;
+                       t->extraParentObjectId = pt->t.chunkId & (~(ALL_EXTRA_FLAGS));
+                       t->extraIsShrinkHeader =  (pt->t.chunkId & EXTRA_SHRINK_FLAG) ? 1 : 0;
+                       t->extraShadows =  (pt->t.chunkId & EXTRA_SHADOWS_FLAG) ? 1 : 0;
+                       t->extraObjectType = pt->t.objectId >> EXTRA_OBJECT_TYPE_SHIFT;
+                       t->objectId &= ~EXTRA_OBJECT_TYPE_MASK;
+                       
+                       if(t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK)
+                       {
+                           t->extraEquivalentObjectId = pt->t.byteCount;
+                       }
+                       else 
+                       {
+                           t->extraFileLength = pt->t.byteCount;
+                       }
+               }
        }
 
        yaffs_DumpPackedTags2(pt);