From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f198.google.com (mail-pg1-f198.google.com [209.85.215.198]) by kanga.kvack.org (Postfix) with ESMTP id 375E76B000E for ; Mon, 15 Oct 2018 23:10:28 -0400 (EDT) Received: by mail-pg1-f198.google.com with SMTP id s141-v6so15982400pgs.23 for ; Mon, 15 Oct 2018 20:10:28 -0700 (PDT) Received: from aserp2120.oracle.com (aserp2120.oracle.com. [141.146.126.78]) by mx.google.com with ESMTPS id k20-v6si12820625pgh.168.2018.10.15.20.10.26 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 15 Oct 2018 20:10:27 -0700 (PDT) Subject: [PATCH 04/26] vfs: exit early from zero length remap operations From: "Darrick J. Wong" Date: Mon, 15 Oct 2018 20:10:23 -0700 Message-ID: <153965942391.1256.1491987046439132016.stgit@magnolia> In-Reply-To: <153965939489.1256.7400115244528045860.stgit@magnolia> References: <153965939489.1256.7400115244528045860.stgit@magnolia> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: david@fromorbit.com, darrick.wong@oracle.com Cc: sandeen@redhat.com, linux-nfs@vger.kernel.org, linux-cifs@vger.kernel.org, linux-unionfs@vger.kernel.org, linux-xfs@vger.kernel.org, linux-mm@kvack.org, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, ocfs2-devel@oss.oracle.com From: Darrick J. Wong If a remap caller asks us to remap to the source file's EOF and the source file has zero bytes, exit early. Signed-off-by: Darrick J. Wong --- fs/read_write.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/read_write.c b/fs/read_write.c index d6e8e242a15f..2456da3f8a41 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1748,6 +1748,8 @@ int vfs_clone_file_prep(struct file *file_in, loff_t pos_in, if (pos_in > isize) return -EINVAL; *len = isize - pos_in; + if (*len == 0) + return 0; } /* Check that we don't violate system file offset limits. */