diff --git a/gio/gbufferedinputstream.c b/gio/gbufferedinputstream.c
index f5090d064..b0e609c0d 100644
--- a/gio/gbufferedinputstream.c
+++ b/gio/gbufferedinputstream.c
@@ -661,10 +661,10 @@ g_buffered_input_stream_real_fill (GBufferedInputStream  *stream,
   in_buffer = priv->end - priv->pos;
 
   /* Never fill more than can fit in the buffer */
-  count = MIN (count, priv->len - in_buffer);
+  count = MIN ((gsize) count, priv->len - in_buffer);
 
   /* If requested length does not fit at end, compact */
-  if (priv->len - priv->end < count)
+  if (priv->len - priv->end < (gsize) count)
     compact_buffer (stream);
 
   base_stream = G_FILTER_INPUT_STREAM (stream)->base_stream;
@@ -1072,10 +1072,10 @@ g_buffered_input_stream_real_fill_async (GBufferedInputStream *stream,
   in_buffer = priv->end - priv->pos;
 
   /* Never fill more than can fit in the buffer */
-  count = MIN (count, priv->len - in_buffer);
+  count = MIN ((gsize) count, priv->len - in_buffer);
 
   /* If requested length does not fit at end, compact */
-  if (priv->len - priv->end < count)
+  if (priv->len - priv->end < (gsize) count)
     compact_buffer (stream);
 
   task = g_task_new (stream, cancellable, callback, user_data);
diff --git a/gio/gbufferedoutputstream.c b/gio/gbufferedoutputstream.c
index 98bda501d..969bbae0b 100644
--- a/gio/gbufferedoutputstream.c
+++ b/gio/gbufferedoutputstream.c
@@ -208,7 +208,7 @@ g_buffered_output_stream_set_buffer_size (GBufferedOutputStream *stream,
 
   if (priv->buffer)
     {
-      size = MAX (size, priv->pos);
+      size = (priv->pos > 0) ? MAX (size, (gsize) priv->pos) : size;
 
       buffer = g_malloc (size);
       memcpy (buffer, priv->buffer, priv->pos);