@@ -1,7 +1,7 @@
 /*
- * Copyright (c) 2008-2021 Jonathan Schleifer <js@nil.im>
+ * Copyright (c) 2008-2022 Jonathan Schleifer <js@nil.im>
  *
  * All rights reserved.
  *
  * This file is part of ObjFW. It may be distributed under the terms of the
  * Q Public License 1.0, which can be found in the file LICENSE.QPL included in
@@ -12,10 +12,12 @@
  * LICENSE.GPLv2 or LICENSE.GPLv3 respectively included in the packaging of this
  * file.
  */
 
 #include "config.h"
+
+#include <errno.h>
 
 #import "OFTarArchive.h"
 #import "OFTarArchiveEntry.h"
 #import "OFTarArchiveEntry+Private.h"
 #import "OFDate.h"
@@ -427,29 +429,32 @@
 	[super dealloc];
 }
 
 - (size_t)lowlevelWriteBuffer: (const void *)buffer length: (size_t)length
 {
-	size_t bytesWritten;
-
 	if (_stream == nil)
 		@throw [OFNotOpenException exceptionWithObject: self];
 
 	if ((uint64_t)length > _toWrite)
 		@throw [OFOutOfRangeException exception];
 
 	@try {
-		bytesWritten = [_stream writeBuffer: buffer
-					     length: length];
+		[_stream writeBuffer: buffer length: length];
 	} @catch (OFWriteFailedException *e) {
+		OFEnsure(e.bytesWritten <= length);
+
 		_toWrite -= e.bytesWritten;
+
+		if (e.errNo == EWOULDBLOCK || e.errNo == EAGAIN)
+			return e.bytesWritten;
+
 		@throw e;
 	}
 
-	_toWrite -= bytesWritten;
+	_toWrite -= length;
 
-	return bytesWritten;
+	return length;
 }
 
 - (bool)lowlevelIsAtEndOfStream
 {
 	if (_stream == nil)