diff --git a/src/vs/workbench/api/electron-browser/mainThreadFileSystem.ts b/src/vs/workbench/api/electron-browser/mainThreadFileSystem.ts
index 3ad9bff063c..0a948e1cfbb 100644
--- a/src/vs/workbench/api/electron-browser/mainThreadFileSystem.ts
+++ b/src/vs/workbench/api/electron-browser/mainThreadFileSystem.ts
@@ -139,10 +139,13 @@ class RemoteFileSystemProvider implements IFileSystemProvider {
 	}
 
 	read(fd: number, pos: number, data: Uint8Array, offset: number, length: number): Promise<number> {
-		return this._proxy.$read(this._handle, fd, pos, RemoteFileSystemProvider._asBuffer(data), offset, length);
+		return this._proxy.$read(this._handle, fd, pos, length).then(readData => {
+			data.set(readData, offset);
+			return readData.byteLength;
+		});
 	}
 
 	write(fd: number, pos: number, data: Uint8Array, offset: number, length: number): Promise<number> {
-		return this._proxy.$write(this._handle, fd, pos, RemoteFileSystemProvider._asBuffer(data), offset, length);
+		return this._proxy.$write(this._handle, fd, pos, Buffer.from(data, offset, length));
 	}
 }
diff --git a/src/vs/workbench/api/node/extHost.protocol.ts b/src/vs/workbench/api/node/extHost.protocol.ts
index 04635c90791..d8e363a64a2 100644
--- a/src/vs/workbench/api/node/extHost.protocol.ts
+++ b/src/vs/workbench/api/node/extHost.protocol.ts
@@ -726,8 +726,8 @@ export interface ExtHostFileSystemShape {
 	$unwatch(handle: number, session: number): void;
 	$open(handle: number, resource: UriComponents): Promise<number>;
 	$close(handle: number, fd: number): Promise<void>;
-	$read(handle: number, fd: number, pos: number, data: Buffer, offset: number, length: number): Promise<number>;
-	$write(handle: number, fd: number, pos: number, data: Buffer, offset: number, length: number): Promise<number>;
+	$read(handle: number, fd: number, pos: number, length: number): Promise<Buffer>;
+	$write(handle: number, fd: number, pos: number, data: Buffer): Promise<number>;
 }
 
 export interface ExtHostSearchShape {
diff --git a/src/vs/workbench/api/node/extHostFileSystem.ts b/src/vs/workbench/api/node/extHostFileSystem.ts
index 9753a6ed749..f1fe101d1c1 100644
--- a/src/vs/workbench/api/node/extHostFileSystem.ts
+++ b/src/vs/workbench/api/node/extHostFileSystem.ts
@@ -290,14 +290,17 @@ export class ExtHostFileSystem implements ExtHostFileSystemShape {
 		return Promise.resolve(this._fsProvider.get(handle).close(fd));
 	}
 
-	$read(handle: number, fd: number, pos: number, data: Buffer, offset: number, length: number): Promise<number> {
+	$read(handle: number, fd: number, pos: number, length: number): Promise<Buffer> {
 		this._checkProviderExists(handle);
-		return Promise.resolve(this._fsProvider.get(handle).read(fd, pos, data, offset, length));
+		const data = Buffer.allocUnsafe(length);
+		return Promise.resolve(this._fsProvider.get(handle).read(fd, pos, data, 0, length)).then(read => {
+			return data.slice(0, read); // don't send zeros
+		});
 	}
 
-	$write(handle: number, fd: number, pos: number, data: Buffer, offset: number, length: number): Promise<number> {
+	$write(handle: number, fd: number, pos: number, data: Buffer): Promise<number> {
 		this._checkProviderExists(handle);
-		return Promise.resolve(this._fsProvider.get(handle).write(fd, pos, data, offset, length));
+		return Promise.resolve(this._fsProvider.get(handle).write(fd, pos, data, 0, data.length));
 	}
 
 }