diff --git a/headers/private/userlandfs/private/Port.h b/headers/private/userlandfs/private/Port.h
index e4498564b4..0ba6a8edf0 100644
--- a/headers/private/userlandfs/private/Port.h
+++ b/headers/private/userlandfs/private/Port.h
@@ -33,10 +33,14 @@ public:
 
 			const Info*			GetInfo() const;
 
-			void*				GetBuffer() const;
-			int32				GetCapacity() const;
+			void*				GetBuffer() const	{ return fBuffer; }
+			int32				GetCapacity() const	{ return fCapacity; }
 
-			status_t			Send(int32 size);
+			void				Reserve(int32 endOffset);
+			void				Unreserve(int32 endOffset);
+			int32				ReservedSize() const { return fReservedSize; }
+
+			status_t			Send(const void* message, int32 size);
 			status_t			Receive(void** _message, size_t* _size,
 									bigtime_t timeout = -1);
 
@@ -46,6 +50,7 @@ private:
 			Info				fInfo;
 			uint8*				fBuffer;
 			int32				fCapacity;
+			int32				fReservedSize;
 			status_t			fInitStatus;
 			bool				fOwner;
 };
diff --git a/headers/private/userlandfs/private/RequestAllocator.h b/headers/private/userlandfs/private/RequestAllocator.h
index 6084c95fa0..1c7b961fe5 100644
--- a/headers/private/userlandfs/private/RequestAllocator.h
+++ b/headers/private/userlandfs/private/RequestAllocator.h
@@ -61,6 +61,8 @@ private:
 			Port*				fPort;
 			Request*			fRequest;
 			int32				fRequestSize;
+			int32				fPortReservedOffset;
+			int32				fRequestOffset;
 			area_id				fAllocatedAreas[MAX_REQUEST_ADDRESS_COUNT];
 			int32				fAllocatedAreaCount;
 			DeferredInitInfo	fDeferredInitInfos[MAX_REQUEST_ADDRESS_COUNT];
diff --git a/src/add-ons/kernel/file_systems/userlandfs/private/Port.cpp b/src/add-ons/kernel/file_systems/userlandfs/private/Port.cpp
index 49cd005c0c..366356abff 100644
--- a/src/add-ons/kernel/file_systems/userlandfs/private/Port.cpp
+++ b/src/add-ons/kernel/file_systems/userlandfs/private/Port.cpp
@@ -21,10 +21,12 @@ static const int32 kMaxPortSize = 64 * 1024;	// 64 kB
 
 // constructor
 Port::Port(int32 size)
-	: fBuffer(NULL),
-	  fCapacity(0),
-	  fInitStatus(B_NO_INIT),
-	  fOwner(true)
+	:
+	fBuffer(NULL),
+	fCapacity(0),
+	fReservedSize(0),
+	fInitStatus(B_NO_INIT),
+	fOwner(true)
 {
 	// adjust size to be within the sane bounds
 	if (size < kMinPortSize)
@@ -57,10 +59,12 @@ Port::Port(int32 size)
 
 // constructor
 Port::Port(const Info* info)
-	: fBuffer(NULL),
-	  fCapacity(0),
-	  fInitStatus(B_NO_INIT),
-	  fOwner(false)
+	:
+	fBuffer(NULL),
+	fCapacity(0),
+	fReservedSize(0),
+	fInitStatus(B_NO_INIT),
+	fOwner(false)
 {
 	// check parameters
 	if (!info || info->owner_port < 0 || info->client_port < 0
@@ -126,35 +130,39 @@ Port::GetInfo() const
 }
 
 
-// GetBuffer
-void*
-Port::GetBuffer() const
+// Reserve
+void
+Port::Reserve(int32 endOffset)
 {
-	return fBuffer;
+	if (endOffset > fReservedSize)
+		fReservedSize = endOffset;
 }
 
 
-// GetCapacity
-int32
-Port::GetCapacity() const
+// Unreserve
+void
+Port::Unreserve(int32 endOffset)
 {
-	return fCapacity;
+	if (endOffset < fReservedSize)
+		fReservedSize = endOffset;
 }
 
 
 // Send
 status_t
-Port::Send(int32 size)
+Port::Send(const void* message, int32 size)
 {
 	if (fInitStatus != B_OK)
 		return fInitStatus;
-	if (size <= 0 || size > fCapacity)
+	if (size <= 0)
 		return B_BAD_VALUE;
+
 	port_id port = (fOwner ? fInfo.client_port : fInfo.owner_port);
 	status_t error;
 	do {
-		error = write_port(port, 0, fBuffer, size);
+		error = write_port(port, 0, message, size);
 	} while (error == B_INTERRUPTED);
+
 	return (fInitStatus = error);
 }
 
diff --git a/src/add-ons/kernel/file_systems/userlandfs/private/RequestAllocator.cpp b/src/add-ons/kernel/file_systems/userlandfs/private/RequestAllocator.cpp
index ce164afb6e..0316b56bd9 100644
--- a/src/add-ons/kernel/file_systems/userlandfs/private/RequestAllocator.cpp
+++ b/src/add-ons/kernel/file_systems/userlandfs/private/RequestAllocator.cpp
@@ -14,13 +14,15 @@
 
 // constructor
 RequestAllocator::RequestAllocator(Port* port)
-	: fError(B_NO_INIT),
-	  fPort(NULL),
-	  fRequest(NULL),
-	  fRequestSize(0),
-	  fAllocatedAreaCount(0),
-	  fDeferredInitInfoCount(0),
-	  fRequestInPortBuffer(false)
+	:
+	fError(B_NO_INIT),
+	fPort(NULL),
+	fRequest(NULL),
+	fRequestSize(0),
+	fPortReservedOffset(0),
+	fAllocatedAreaCount(0),
+	fDeferredInitInfoCount(0),
+	fRequestInPortBuffer(false)
 {
 	Init(port);
 }
@@ -39,6 +41,7 @@ RequestAllocator::Init(Port* port)
 	if (port) {
 		fPort = port;
 		fError = fPort->InitCheck();
+		fPortReservedOffset = fPort->ReservedSize();
 	}
 	return fError;
 }
@@ -47,20 +50,26 @@ RequestAllocator::Init(Port* port)
 void
 RequestAllocator::Uninit()
 {
-	if (!fRequestInPortBuffer)
+	if (fRequestInPortBuffer)
+		fPort->Unreserve(fPortReservedOffset);
+	else
 		free(fRequest);
+
 	for (int32 i = 0; i < fAllocatedAreaCount; i++)
 		delete_area(fAllocatedAreas[i]);
 	fAllocatedAreaCount = 0;
+
 	for (int32 i = 0; i < fDeferredInitInfoCount; i++) {
 		if (fDeferredInitInfos[i].inPortBuffer)
 			free(fDeferredInitInfos[i].data);
 	}
+
 	fDeferredInitInfoCount = 0;
 	fError = B_NO_INIT;
 	fPort = NULL;
 	fRequest = NULL;
 	fRequestSize = 0;
+	fPortReservedOffset = 0;
 }
 
 // Error
@@ -96,11 +105,18 @@ RequestAllocator::AllocateRequest(int32 size)
 {
 	if (fError != B_OK)
 		RETURN_ERROR(fError);
-	if (size < (int32)sizeof(Request) || size > fPort->GetCapacity())
+
+	fRequestOffset = (fPortReservedOffset + 7) / 8 * 8;
+
+	if (size < (int32)sizeof(Request)
+		|| fRequestOffset + size > fPort->GetCapacity()) {
 		RETURN_ERROR(fError = B_BAD_VALUE);
-	fRequest = (Request*)fPort->GetBuffer();
+	}
+
+	fRequest = (Request*)((uint8*)fPort->GetBuffer() + fRequestOffset);
 	fRequestSize = size;
 	fRequestInPortBuffer = true;
+	fPort->Reserve(fRequestOffset + fRequestSize);
 	return B_OK;
 }
 
@@ -129,6 +145,7 @@ RequestAllocator::ReadRequest(bigtime_t timeout)
 
 	// init the request
 	fRequest = (Request*)message;
+	fRequestOffset = 0;
 	fRequestSize = messageSize;
 	fRequestInPortBuffer = false;
 
@@ -185,9 +202,10 @@ RequestAllocator::AllocateAddress(Address& address, int32 size, int32 align,
 	// get the next free aligned offset in the port buffer
 	int32 offset = (fRequestSize + align - 1) / align * align;
 	// allocate the data
-	if (offset + size <= fPort->GetCapacity()) {
+	if (fRequestOffset + offset + size <= fPort->GetCapacity()) {
 		// there's enough free space in the port buffer
 		fRequestSize = offset + size;
+		fPort->Reserve(fRequestOffset + fRequestSize);
 		if (deferredInit) {
 			DeferredInitInfo& info
 				= fDeferredInitInfos[fDeferredInitInfoCount];
diff --git a/src/add-ons/kernel/file_systems/userlandfs/private/RequestPort.cpp b/src/add-ons/kernel/file_systems/userlandfs/private/RequestPort.cpp
index 38af9dfcc5..14b9f1a78b 100644
--- a/src/add-ons/kernel/file_systems/userlandfs/private/RequestPort.cpp
+++ b/src/add-ons/kernel/file_systems/userlandfs/private/RequestPort.cpp
@@ -77,9 +77,8 @@ RequestPort::SendRequest(RequestAllocator* allocator)
 	// check initialization and parameters
 	if (InitCheck() != B_OK)
 		RETURN_ERROR(InitCheck());
-	if (!allocator || allocator->GetRequest() != fPort.GetBuffer()
-		|| allocator->GetRequestSize() < (int32)sizeof(Request)
-		|| allocator->GetRequestSize() > fPort.GetCapacity()) {
+	if (!allocator || allocator->GetRequest() == NULL
+		|| allocator->GetRequestSize() < (int32)sizeof(Request)) {
 		RETURN_ERROR(B_BAD_VALUE);
 	}
 	allocator->FinishDeferredInit();
@@ -97,7 +96,8 @@ RequestPort::SendRequest(RequestAllocator* allocator)
 		debugger("Request is not a kernel request.");
 	}
 #endif
-	RETURN_ERROR(fPort.Send(allocator->GetRequestSize()));
+	RETURN_ERROR(fPort.Send(allocator->GetRequest(),
+		allocator->GetRequestSize()));
 }
 
 // SendRequest