From: "Darrick J. Wong" <darrick.wong@oracle.com>
To: Dave Chinner <david@fromorbit.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
Subject: Re: [PATCH 05/25] vfs: avoid problematic remapping requests into partial EOF block
Date: Fri, 12 Oct 2018 09:07:59 -0700 [thread overview]
Message-ID: <20181012160759.GF28243@magnolia> (raw)
In-Reply-To: <20181012001615.GR6311@dastard>
On Fri, Oct 12, 2018 at 11:16:16AM +1100, Dave Chinner wrote:
> On Wed, Oct 10, 2018 at 09:12:54PM -0700, Darrick J. Wong wrote:
> > From: Darrick J. Wong <darrick.wong@oracle.com>
> >
> > A deduplication data corruption is exposed by fstests generic/505 on
> > XFS. It is caused by extending the block match range to include the
> > partial EOF block, but then allowing unknown data beyond EOF to be
> > considered a "match" to data in the destination file because the
> > comparison is only made to the end of the source file. This corrupts the
> > destination file when the source extent is shared with it.
> >
> > The VFS remapping prep functions only support whole block dedupe, but
> > we still need to appear to support whole file dedupe correctly. Hence
> > if the dedupe request includes the last block of the souce file, don't
> > include it in the actual dedupe operation. If the rest of the range
> > dedupes successfully, then reject the entire request. A subsequent
> > patch will enable us to shorten dedupe requests correctly.
>
> Ok, so this patch rejects whole file dedupe requests, and then a
> later patch adds support back in for it?
>
> Doesn't that leave a bisect landmine behind? Why separate the
> functionality like this?
Heh, it's a leftover from when I was trying to undo the behavior that
bytes_deduped == len even if we rounded down. I gave up on that, so
this can match the xfs patch.
--D
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@fromorbit.com
next prev parent reply other threads:[~2018-10-12 16:08 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-11 4:12 [PATCH v3 00/25] fs: fixes for serious clone/dedupe problems Darrick J. Wong
2018-10-11 4:12 ` [PATCH 01/25] xfs: add a per-xfs trace_printk macro Darrick J. Wong
2018-10-11 13:39 ` Christoph Hellwig
2018-10-11 23:34 ` Darrick J. Wong
2018-10-11 4:12 ` [PATCH 02/25] vfs: vfs_clone_file_prep_inodes should return EINVAL for a clone from beyond EOF Darrick J. Wong
2018-10-11 13:40 ` Christoph Hellwig
2018-10-11 4:12 ` [PATCH 03/25] vfs: check file ranges before cloning files Darrick J. Wong
2018-10-11 13:42 ` Christoph Hellwig
2018-10-11 14:13 ` Amir Goldstein
2018-10-11 4:12 ` [PATCH 04/25] vfs: strengthen checking of file range inputs to generic_remap_checks Darrick J. Wong
2018-10-11 13:43 ` Christoph Hellwig
2018-10-11 4:12 ` [PATCH 05/25] vfs: avoid problematic remapping requests into partial EOF block Darrick J. Wong
2018-10-12 0:16 ` Dave Chinner
2018-10-12 16:07 ` Darrick J. Wong [this message]
2018-10-12 20:22 ` Filipe Manana
2018-10-15 0:31 ` Dave Chinner
2018-11-02 12:04 ` Filipe Manana
2018-11-02 17:42 ` Darrick J. Wong
2018-11-02 18:18 ` Filipe Manana
2018-11-02 19:05 ` Filipe Manana
2018-10-11 4:13 ` [PATCH 06/25] vfs: skip zero-length dedupe requests Darrick J. Wong
2018-10-11 4:13 ` [PATCH 07/25] vfs: combine the clone and dedupe into a single remap_file_range Darrick J. Wong
2018-10-11 4:13 ` [PATCH 08/25] vfs: rename vfs_clone_file_prep to be more descriptive Darrick J. Wong
2018-10-11 4:13 ` [PATCH 09/25] vfs: rename clone_verify_area to remap_verify_area Darrick J. Wong
2018-10-11 4:13 ` [PATCH 10/25] vfs: create generic_remap_file_range_touch to update inode metadata Darrick J. Wong
2018-10-11 4:13 ` [PATCH 11/25] vfs: pass remap flags to generic_remap_file_range_prep Darrick J. Wong
2018-10-11 4:13 ` [PATCH 12/25] vfs: pass remap flags to generic_remap_checks Darrick J. Wong
2018-10-11 4:13 ` [PATCH 13/25] vfs: make remap_file_range functions take and return bytes completed Darrick J. Wong
2018-10-11 4:14 ` [PATCH 14/25] vfs: plumb RFR_* remap flags through the vfs clone functions Darrick J. Wong
2018-10-11 4:14 ` [PATCH 15/25] vfs: plumb RFR_* remap flags through the vfs dedupe functions Darrick J. Wong
2018-10-11 4:14 ` [PATCH 16/25] vfs: make remapping to source file eof more explicit Darrick J. Wong
2018-10-11 4:14 ` [PATCH 17/25] vfs: enable remap callers that can handle short operations Darrick J. Wong
2018-10-11 5:15 ` Amir Goldstein
2018-10-11 16:04 ` Darrick J. Wong
2018-10-11 16:05 ` [PATCH v2 " Darrick J. Wong
2018-10-11 4:14 ` [PATCH 18/25] vfs: hide file range comparison function Darrick J. Wong
2018-10-11 4:14 ` [PATCH 19/25] vfs: implement opportunistic short dedupe Darrick J. Wong
2018-10-11 4:14 ` [PATCH 20/25] ocfs2: truncate page cache for clone destination file before remapping Darrick J. Wong
2018-10-11 4:14 ` [PATCH 21/25] ocfs2: fix pagecache truncation prior to reflink Darrick J. Wong
2018-10-11 4:15 ` [PATCH 22/25] ocfs2: support partial clone range and dedupe range Darrick J. Wong
2018-10-11 4:15 ` [PATCH 23/25] xfs: fix pagecache truncation prior to reflink Darrick J. Wong
2018-10-12 1:15 ` Dave Chinner
2018-10-11 4:15 ` [PATCH 24/25] xfs: support returning partial reflink results Darrick J. Wong
2018-10-12 1:22 ` Dave Chinner
2018-10-12 16:06 ` Darrick J. Wong
2018-10-11 4:15 ` [PATCH 25/25] xfs: remove redundant remap partial EOF block checks Darrick J. Wong
2018-10-12 1:22 ` Dave Chinner
2018-10-11 8:33 ` [PATCH v3 00/25] fs: fixes for serious clone/dedupe problems Amir Goldstein
2018-10-11 15:55 ` Darrick J. Wong
2018-10-13 0:05 [PATCH v4 " Darrick J. Wong
2018-10-13 0:06 ` [PATCH 05/25] vfs: avoid problematic remapping requests into partial EOF block Darrick J. Wong
2018-10-14 17:11 ` Christoph Hellwig
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