From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from userp2130.oracle.com ([156.151.31.86]:40630 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725789AbeJJI0l (ORCPT ); Wed, 10 Oct 2018 04:26:41 -0400 Date: Tue, 9 Oct 2018 18:06:52 -0700 From: "Darrick J. Wong" To: Dave Chinner 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 Subject: Re: [PATCH v2 00/25] fs: fixes for serious clone/dedupe problems Message-ID: <20181010010652.GK28243@magnolia> References: <153913023835.32295.13962696655740190941.stgit@magnolia> <20181010010208.GI6311@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20181010010208.GI6311@dastard> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, Oct 10, 2018 at 12:02:08PM +1100, Dave Chinner wrote: > On Tue, Oct 09, 2018 at 05:10:38PM -0700, Darrick J. Wong wrote: > > Hi all, > > > > Dave, Eric, and I have been chasing a stale data exposure bug in the XFS > > reflink implementation, and tracked it down to reflink forgetting to do > > some of the file-extending activities that must happen for regular > > writes. > > > > We then started auditing the clone, dedupe, and copyfile code and > > realized that from a file contents perspective, clonerange isn't any > > different from a regular file write. Unfortunately, we also noticed > > that *unlike* a regular write, clonerange skips a ton of overflow > > checks, such as validating the ranges against s_maxbytes, MAX_NON_LFS, > > and RLIMIT_FSIZE. We also observed that cloning into a file did not > > strip security privileges (suid, capabilities) like a regular write > > would. I also noticed that xfs and ocfs2 need to dump the page cache > > before remapping blocks, not after. > > > > In fixing the range checking problems I also realized that both dedupe > > and copyfile tell userspace how much of the requested operation was > > acted upon. Since the range validation can shorten a clone request (or > > we can ENOSPC midway through), we might as well plumb the short > > operation reporting back through the VFS indirection code to userspace. > > > > So, here's the whole giant pile of patches[1] that fix all the problems. > > The patch "generic: test reflink side effects" recently sent to fstests > > exercises the fixes in this series. Tests are in [2]. > > Can you rebase this on the for-next branch on the xfs tree which > already contains some of the initial fixes in the series and a > couple of other reflink/dedupe data corruption fixes? I'm planning > on pushing them to Greg tomorrow, so you'll have to do this soon > anyway.... I was planning to do that tomorrow, but figured I might as well scrape for review comments in the mean time. --D > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com