diff --git a/src/add-ons/kernel/file_systems/udf/MetadataPartition.cpp b/src/add-ons/kernel/file_systems/udf/MetadataPartition.cpp
index bd4dec22b7..b7fc00eb4f 100644
--- a/src/add-ons/kernel/file_systems/udf/MetadataPartition.cpp
+++ b/src/add-ons/kernel/file_systems/udf/MetadataPartition.cpp
@@ -30,7 +30,7 @@ MetadataPartition::~MetadataPartition()
 /*! \brief Maps the given logical block to a physical block on disc.
 */
 status_t
-MetadataPartition::MapBlock(uint32 logicalBlock, uint32 &physicalBlock)
+MetadataPartition::MapBlock(uint32 logicalBlock, off_t &physicalBlock)
 {
 	return B_NOT_IMPLEMENTED;
 }
diff --git a/src/add-ons/kernel/file_systems/udf/MetadataPartition.h b/src/add-ons/kernel/file_systems/udf/MetadataPartition.h
index 35cde8546e..4c0dd10377 100644
--- a/src/add-ons/kernel/file_systems/udf/MetadataPartition.h
+++ b/src/add-ons/kernel/file_systems/udf/MetadataPartition.h
@@ -31,7 +31,7 @@ public:
 	                  uint32 allocationUnitSize, uint16 alignmentUnitSize,
 	                  bool metadataIsDuplicated);
 	virtual ~MetadataPartition();
-	virtual status_t MapBlock(uint32 logicalBlock, uint32 &physicalBlock);
+	virtual status_t MapBlock(uint32 logicalBlock, off_t &physicalBlock);
 	
 	status_t InitCheck();
 
diff --git a/src/add-ons/kernel/file_systems/udf/Partition.h b/src/add-ons/kernel/file_systems/udf/Partition.h
index db4566a7c0..33cc94f5ca 100644
--- a/src/add-ons/kernel/file_systems/udf/Partition.h
+++ b/src/add-ons/kernel/file_systems/udf/Partition.h
@@ -19,7 +19,9 @@ namespace Udf {
 class Partition {
 public:
 	virtual ~Partition() {}
-	virtual status_t MapBlock(uint32 logicalBlock, uint32 &physicalBlock) = 0;
+	virtual status_t MapBlock(uint32 logicalBlock, off_t &physicalBlock) = 0;
+//	virtual status_t MapExtent(uint32 logicalBlock, uint32 logicalLength,
+//	                           uint32 &physicalBlock, uint32 &physicalLength) = 0;
 };
 
 };	// namespace Udf
diff --git a/src/add-ons/kernel/file_systems/udf/PhysicalPartition.cpp b/src/add-ons/kernel/file_systems/udf/PhysicalPartition.cpp
index 3179b0e8b1..605e54f8cb 100644
--- a/src/add-ons/kernel/file_systems/udf/PhysicalPartition.cpp
+++ b/src/add-ons/kernel/file_systems/udf/PhysicalPartition.cpp
@@ -25,12 +25,14 @@ PhysicalPartition::~PhysicalPartition()
 	start of the physical partition.
 */
 status_t
-PhysicalPartition::MapBlock(uint32 logicalBlock, uint32 &physicalBlock)
+PhysicalPartition::MapBlock(uint32 logicalBlock, off_t &physicalBlock)
 {
+	DEBUG_INIT_ETC(CF_PUBLIC, "PhysicalPartition", ("%ld", logicalBlock));
 	if (logicalBlock >= fLength)
 		return B_BAD_ADDRESS;
 	else {
 		physicalBlock = fStart + logicalBlock;
+		PRINT(("mapped %ld to %Ld\n", logicalBlock, physicalBlock));
 		return B_OK;
 	}
 }
diff --git a/src/add-ons/kernel/file_systems/udf/PhysicalPartition.h b/src/add-ons/kernel/file_systems/udf/PhysicalPartition.h
index 5a9d161530..baff3bdb75 100644
--- a/src/add-ons/kernel/file_systems/udf/PhysicalPartition.h
+++ b/src/add-ons/kernel/file_systems/udf/PhysicalPartition.h
@@ -28,7 +28,7 @@ class PhysicalPartition : public Partition {
 public:
 	PhysicalPartition(uint16 number, uint32 start, uint32 length);
 	virtual ~PhysicalPartition();
-	virtual status_t MapBlock(uint32 logicalBlock, uint32 &physicalBlock);
+	virtual status_t MapBlock(uint32 logicalBlock, off_t &physicalBlock);
 
 	uint16 Number() const { return fNumber; }
 	uint32 Start() const { return fStart; }
diff --git a/src/add-ons/kernel/file_systems/udf/SparablePartition.cpp b/src/add-ons/kernel/file_systems/udf/SparablePartition.cpp
index 3ac2393b22..dd71f2f35c 100644
--- a/src/add-ons/kernel/file_systems/udf/SparablePartition.cpp
+++ b/src/add-ons/kernel/file_systems/udf/SparablePartition.cpp
@@ -40,7 +40,7 @@ SparablePartition::~SparablePartition()
 	the	start of the physical partition.
 */
 status_t
-SparablePartition::MapBlock(uint32 logicalBlock, uint32 &physicalBlock)
+SparablePartition::MapBlock(uint32 logicalBlock, off_t &physicalBlock)
 {
 	status_t error = InitCheck();
 	if (!error) {
@@ -49,10 +49,10 @@ SparablePartition::MapBlock(uint32 logicalBlock, uint32 &physicalBlock)
 		else {
 			// Check for the logical block in the sparing tables. If not
 			// found, map directly to physical space.
-			
+
 			//physicalBlock = fStart + logicalBlock;
 			//return B_OK;
-			error = B_NOT_IMPLEMENTED;
+			error = B_ERROR;
 		}
 	}
 	return error;
diff --git a/src/add-ons/kernel/file_systems/udf/SparablePartition.h b/src/add-ons/kernel/file_systems/udf/SparablePartition.h
index db0e38088e..ce8f0a8768 100644
--- a/src/add-ons/kernel/file_systems/udf/SparablePartition.h
+++ b/src/add-ons/kernel/file_systems/udf/SparablePartition.h
@@ -12,6 +12,7 @@
 
 #include <kernel_cpp.h>
 
+#include "DiskStructures.h"
 #include "Partition.h"
 #include "UdfDebug.h"
 
@@ -35,7 +36,7 @@ public:
 	SparablePartition(uint16 number, uint32 start, uint32 length, uint16 packetLength,
 	                  uint8 tableCount, uint32 *tableLocations);
 	virtual ~SparablePartition();
-	virtual status_t MapBlock(uint32 logicalBlock, uint32 &physicalBlock);
+	virtual status_t MapBlock(uint32 logicalBlock, off_t &physicalBlock);
 	
 	status_t InitCheck();
 
@@ -46,7 +47,7 @@ public:
 	uint8 TableCount() const { return fTableCount; }
 	
 	//! Maximum number of redundant sparing tables per SparablePartition
-	static const uint8 kMaxSparingTableCount = 4;
+	static const uint8 kMaxSparingTableCount = UDF_MAX_SPARING_TABLE_COUNT;
 private:
 	uint16 fNumber;
 	uint32 fStart;
diff --git a/src/add-ons/kernel/file_systems/udf/VirtualPartition.cpp b/src/add-ons/kernel/file_systems/udf/VirtualPartition.cpp
index 64375d74ea..d5216060ec 100644
--- a/src/add-ons/kernel/file_systems/udf/VirtualPartition.cpp
+++ b/src/add-ons/kernel/file_systems/udf/VirtualPartition.cpp
@@ -30,7 +30,7 @@ VirtualPartition::~VirtualPartition()
 	VirtualPartition object's physical partition.
 */
 status_t
-VirtualPartition::MapBlock(uint32 logicalBlock, uint32 &physicalBlock)
+VirtualPartition::MapBlock(uint32 logicalBlock, off_t &physicalBlock)
 {
 	return B_NOT_IMPLEMENTED;
 }
diff --git a/src/add-ons/kernel/file_systems/udf/VirtualPartition.h b/src/add-ons/kernel/file_systems/udf/VirtualPartition.h
index 1b8db091db..5870f412ca 100644
--- a/src/add-ons/kernel/file_systems/udf/VirtualPartition.h
+++ b/src/add-ons/kernel/file_systems/udf/VirtualPartition.h
@@ -34,7 +34,7 @@ class VirtualPartition : public Partition {
 public:
 	VirtualPartition(PhysicalPartition &physicalPartition);
 	virtual ~VirtualPartition();
-	virtual status_t MapBlock(uint32 logicalBlock, uint32 &physicalBlock);
+	virtual status_t MapBlock(uint32 logicalBlock, off_t &physicalBlock);
 	
 	status_t InitCheck();
 private: