--- linux-2.6.27.6/fs/yaffs2/yaffs_packedtags2.c	1970-01-01 08:00:00.000000000 +0800
+++ linux-2.6.27.6.yaffs/fs/yaffs2/yaffs_packedtags2.c	2011-05-08 18:01:07.000000000 +0800
@@ -0,0 +1,198 @@
+/*
+ * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
+ *
+ * Copyright (C) 2002-2007 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * 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 General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include "yaffs_packedtags2.h"
+#include "yportenv.h"
+#include "yaffs_trace.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_DumpPackedTags2TagsPart(const yaffs_PackedTags2TagsPart *ptt)
+{
+	T(YAFFS_TRACE_MTD,
+	  (TSTR("packed tags obj %d chunk %d byte %d seq %d" TENDSTR),
+	   ptt->objectId, ptt->chunkId, ptt->byteCount,
+	   ptt->sequenceNumber));
+}
+static void yaffs_DumpPackedTags2(const yaffs_PackedTags2 *pt)
+{
+	yaffs_DumpPackedTags2TagsPart(&pt->t);
+}
+
+static void yaffs_DumpTags2(const yaffs_ExtendedTags *t)
+{
+	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), t->eccResult, t->blockBad, t->chunkUsed, t->objectId,
+	   t->chunkId, t->byteCount, t->chunkDeleted, t->serialNumber,
+	   t->sequenceNumber));
+
+}
+
+void yaffs_PackTags2TagsPart(yaffs_PackedTags2TagsPart *ptt,
+		const yaffs_ExtendedTags *t)
+{
+	ptt->chunkId = t->chunkId;
+	ptt->sequenceNumber = t->sequenceNumber;
+	ptt->byteCount = t->byteCount;
+	ptt->objectId = t->objectId;
+
+	if (t->chunkId == 0 && t->extraHeaderInfoAvailable) {
+		/* Store the extra header info instead */
+		/* We save the parent object in the chunkId */
+		ptt->chunkId = EXTRA_HEADER_INFO_FLAG
+			| t->extraParentObjectId;
+		if (t->extraIsShrinkHeader)
+			ptt->chunkId |= EXTRA_SHRINK_FLAG;
+		if (t->extraShadows)
+			ptt->chunkId |= EXTRA_SHADOWS_FLAG;
+
+		ptt->objectId &= ~EXTRA_OBJECT_TYPE_MASK;
+		ptt->objectId |=
+		    (t->extraObjectType << EXTRA_OBJECT_TYPE_SHIFT);
+
+		if (t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK)
+			ptt->byteCount = t->extraEquivalentObjectId;
+		else if (t->extraObjectType == YAFFS_OBJECT_TYPE_FILE)
+			ptt->byteCount = t->extraFileLength;
+		else
+			ptt->byteCount = 0;
+	}
+
+	yaffs_DumpPackedTags2TagsPart(ptt);
+	yaffs_DumpTags2(t);
+}
+
+
+void yaffs_PackTags2(yaffs_PackedTags2 *pt, const yaffs_ExtendedTags *t, int tagsECC)
+{
+	yaffs_PackTags2TagsPart(&pt->t, t);
+
+	if(tagsECC)
+		yaffs_ECCCalculateOther((unsigned char *)&pt->t,
+					sizeof(yaffs_PackedTags2TagsPart),
+					&pt->ecc);
+}
+
+
+void yaffs_UnpackTags2TagsPart(yaffs_ExtendedTags *t,
+		yaffs_PackedTags2TagsPart *ptt)
+{
+
+	memset(t, 0, sizeof(yaffs_ExtendedTags));
+
+	yaffs_InitialiseTags(t);
+
+	if (ptt->sequenceNumber != 0xFFFFFFFF) {
+		t->blockBad = 0;
+		t->chunkUsed = 1;
+		t->objectId = ptt->objectId;
+		t->chunkId = ptt->chunkId;
+		t->byteCount = ptt->byteCount;
+		t->chunkDeleted = 0;
+		t->serialNumber = 0;
+		t->sequenceNumber = ptt->sequenceNumber;
+
+		/* Do extra header info stuff */
+
+		if (ptt->chunkId & EXTRA_HEADER_INFO_FLAG) {
+			t->chunkId = 0;
+			t->byteCount = 0;
+
+			t->extraHeaderInfoAvailable = 1;
+			t->extraParentObjectId =
+			    ptt->chunkId & (~(ALL_EXTRA_FLAGS));
+			t->extraIsShrinkHeader =
+			    (ptt->chunkId & EXTRA_SHRINK_FLAG) ? 1 : 0;
+			t->extraShadows =
+			    (ptt->chunkId & EXTRA_SHADOWS_FLAG) ? 1 : 0;
+			t->extraObjectType =
+			    ptt->objectId >> EXTRA_OBJECT_TYPE_SHIFT;
+			t->objectId &= ~EXTRA_OBJECT_TYPE_MASK;
+
+			if (t->extraObjectType == YAFFS_OBJECT_TYPE_HARDLINK)
+				t->extraEquivalentObjectId = ptt->byteCount;
+			else
+				t->extraFileLength = ptt->byteCount;
+		}
+	}
+
+	yaffs_DumpPackedTags2TagsPart(ptt);
+	yaffs_DumpTags2(t);
+
+}
+
+
+void yaffs_UnpackTags2(yaffs_ExtendedTags *t, yaffs_PackedTags2 *pt, int tagsECC)
+{
+
+	yaffs_ECCResult eccResult = YAFFS_ECC_RESULT_NO_ERROR;
+
+	if (pt->t.sequenceNumber != 0xFFFFFFFF &&
+	    tagsECC){
+		/* Chunk is in use and we need to do ECC */
+		
+		yaffs_ECCOther ecc;
+		int result;
+		yaffs_ECCCalculateOther((unsigned char *)&pt->t,
+					sizeof(yaffs_PackedTags2TagsPart),
+					&ecc);
+		result = yaffs_ECCCorrectOther((unsigned char *)&pt->t,
+						sizeof(yaffs_PackedTags2TagsPart),
+						&pt->ecc, &ecc);
+		switch (result) {
+			case 0:
+				eccResult = YAFFS_ECC_RESULT_NO_ERROR;
+				break;
+			case 1:
+				eccResult = YAFFS_ECC_RESULT_FIXED;
+				break;
+			case -1:
+				eccResult = YAFFS_ECC_RESULT_UNFIXED;
+				break;
+			default:
+				eccResult = YAFFS_ECC_RESULT_UNKNOWN;
+		}
+	}
+
+	yaffs_UnpackTags2TagsPart(t, &pt->t);
+
+	t->eccResult = eccResult;
+
+	yaffs_DumpPackedTags2(pt);
+	yaffs_DumpTags2(t);
+}
+
