commit 687275cd532f8f8ad710acd222a0c76625da53c6
Author: Jeremy Allison <jra@samba.org>
Date:   Thu May 8 22:07:35 2008 -0700

    Fix bug #5452 - smbclient put always creates zero length
    files. Thanks to Kai Engert <kengert@redhat.com> for
    reporting.
    Jeremy.

diff --git a/source/lib/xfile.c b/source/lib/xfile.c
index d20a95b..e44a92d 100644
--- a/source/lib/xfile.c
+++ b/source/lib/xfile.c
@@ -263,13 +263,13 @@ int x_fflush(XFILE *f)
 
 	if (f->flags & X_FLAG_ERROR) return -1;
 
+	if (f->bufused == 0 || !f->buf) return 0;
+
 	if ((f->open_flags & O_ACCMODE) != O_WRONLY) {
 		errno = EINVAL;
 		return -1;
 	}
 
-	if (f->bufused == 0 || !f->buf) return 0;
-
 	ret = write(f->fd, f->buf, f->bufused);
 	if (ret == -1) return -1;