Return-Path: Received: from zeniv.linux.org.uk ([195.92.253.2]:35012 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751101AbbKJA4x (ORCPT ); Mon, 9 Nov 2015 19:56:53 -0500 Date: Tue, 10 Nov 2015 00:56:45 +0000 From: Al Viro To: Anna Schumaker Cc: linux-nfs@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org, zab@zabbo.net, clm@fb.com, darrick.wong@oracle.com, mtk.manpages@gmail.com, andros@netapp.com, hch@infradead.org Subject: Re: [PATCH v8 4/4] vfs: Add vfs_copy_file_range() support for pagecache copies Message-ID: <20151110005645.GX22011@ZenIV.linux.org.uk> References: <1446844701-848-1-git-send-email-Anna.Schumaker@Netapp.com> <1446844701-848-5-git-send-email-Anna.Schumaker@Netapp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <1446844701-848-5-git-send-email-Anna.Schumaker@Netapp.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Fri, Nov 06, 2015 at 04:18:20PM -0500, Anna Schumaker wrote: > I moved the rw_verify_area() calls into the fallback code since some > filesystems can handle reflinking a large range. Take a look at rw_verify_area() - it does a lot more than "trim down to 2Gb" - starting with "deal with mandatory locks". LSM checks as well... So that one is bogus, IMO. I've no problem with fallback per se, but rw_verify_area() should be unconditional here. If anything, we might add a variant that would skip the "trim down to 2Gb" and use it there, but skipping it entirely is wrong.