From: Adam Borowski <kilobyte@angband.pl>
To: Neal Gompa <ngompa13@gmail.com>
Cc: Jan Kara <jack@suse.cz>, linux-nvdimm <linux-nvdimm@lists.01.org>,
"Darrick J. Wong" <darrick.wong@oracle.com>,
david <david@fromorbit.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Shiyang Ruan <ruansy.fnst@fujitsu.com>,
linux-xfs <linux-xfs@vger.kernel.org>,
ocfs2-devel@oss.oracle.com, Al Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Btrfs BTRFS <linux-btrfs@vger.kernel.org>
Subject: Re: [Ocfs2-devel] [PATCH v2 00/10] fsdax, xfs: Add reflink&dedupe support for fsdax
Date: Sat, 13 Mar 2021 23:00:56 +0100 [thread overview]
Message-ID: <YE02GArtVnwEeJML@angband.pl> (raw)
In-Reply-To: <CAEg-Je-JCW5xa6w5Z9n7+UNnLju251SmqnXiReA2v41fFaXAtw@mail.gmail.com>
On Sat, Mar 13, 2021 at 11:24:00AM -0500, Neal Gompa wrote:
> On Sat, Mar 13, 2021 at 8:09 AM Adam Borowski <kilobyte@angband.pl> wrote:
> >
> > On Wed, Mar 10, 2021 at 02:26:43PM +0000, Matthew Wilcox wrote:
> > > On Wed, Mar 10, 2021 at 08:21:59AM -0600, Goldwyn Rodrigues wrote:
> > > > DAX on btrfs has been attempted[1]. Of course, we could not
> > >
> > > But why? A completeness fetish? I don't understand why you decided
> > > to do this work.
> >
> > * xfs can shapshot only single files, btrfs entire subvolumes
> > * btrfs-send|receive
> > * enumeration of changed parts of a file
>
> XFS cannot do snapshots since it lacks metadata COW. XFS reflinking is
> primarily for space efficiency.
A reflink is a single-file snapshot.
My work team really wants this very patchset -- reflinks on DAX allow
backups and/or checkpointing, without stopping the world (there's a single
file, "pool", here).
Besides, you can still get poor-man's whole-subvolume(/directory)
snapshots by manually walking the tree and reflinking everything.
That's not atomic -- but rsync isn't atomic either. That's enough for
eg. dnf/dpkg purposes.
Meow!
--
⢀⣴⠾⠻⢶⣦⠀
⣾⠁⢰⠒⠀⣿⡁
⢿⡄⠘⠷⠚⠋⠀ NADIE anticipa la inquisición de españa!
⠈⠳⣄⠀⠀⠀⠀
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prev parent reply other threads:[~2021-03-23 15:46 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-26 0:20 [Ocfs2-devel] [PATCH v2 00/10] fsdax, xfs: Add reflink&dedupe support for fsdax Shiyang Ruan
2021-02-26 0:20 ` [Ocfs2-devel] [PATCH v2 01/10] fsdax: Factor helpers to simplify dax fault code Shiyang Ruan
2021-03-03 9:13 ` Christoph Hellwig
2021-02-26 0:20 ` [Ocfs2-devel] [PATCH v2 02/10] fsdax: Factor helper: dax_fault_actor() Shiyang Ruan
2021-03-03 9:28 ` Christoph Hellwig
2021-03-12 9:01 ` ruansy.fnst
2021-02-26 0:20 ` [Ocfs2-devel] [PATCH v2 03/10] fsdax: Output address in dax_iomap_pfn() and rename it Shiyang Ruan
2021-02-26 0:20 ` [Ocfs2-devel] [PATCH v2 05/10] fsdax: Replace mmap entry in case of CoW Shiyang Ruan
2021-03-03 9:30 ` Christoph Hellwig
2021-03-03 9:41 ` ruansy.fnst
2021-03-03 9:44 ` Christoph Hellwig
2021-03-03 9:48 ` Christoph Hellwig
2021-02-26 0:20 ` [Ocfs2-devel] [PATCH v2 08/10] fsdax: Dedup file range to use a compare function Shiyang Ruan
2021-02-26 8:28 ` Shiyang Ruan
2021-03-03 8:20 ` Joe Perches
2021-03-03 8:45 ` ruansy.fnst
2021-03-03 9:04 ` Joe Perches
2021-03-03 9:39 ` hch
2021-03-03 9:46 ` ruansy.fnst
2021-03-04 5:42 ` [Ocfs2-devel] [RESEND PATCH v2.1 " Shiyang Ruan
2021-02-26 0:20 ` [Ocfs2-devel] [PATCH v2 09/10] fs/xfs: Handle CoW for fsdax write() path Shiyang Ruan
2021-03-03 9:43 ` Christoph Hellwig
2021-03-03 9:57 ` ruansy.fnst
2021-03-03 10:43 ` Christoph Hellwig
2021-03-04 1:35 ` ruansy.fnst
2021-02-26 0:20 ` [Ocfs2-devel] [PATCH v2 10/10] fs/xfs: Add dedupe support for fsdax Shiyang Ruan
2021-02-26 9:45 ` [Ocfs2-devel] Question about the "EXPERIMENTAL" tag for dax in XFS ruansy.fnst
2021-02-26 19:04 ` Darrick J. Wong
2021-02-26 19:24 ` Dan Williams
2021-02-26 20:51 ` Dave Chinner
2021-02-26 20:59 ` Dan Williams
2021-02-26 21:27 ` Dave Chinner
2021-02-26 22:41 ` Dan Williams
2021-02-27 22:36 ` Dave Chinner
2021-02-27 23:40 ` Dan Williams
2021-02-28 22:38 ` Dave Chinner
2021-03-01 20:55 ` Dan Williams
2021-03-01 22:46 ` Dave Chinner
2021-03-02 0:32 ` Dan Williams
2021-03-02 2:42 ` Dave Chinner
2021-03-02 3:33 ` Dan Williams
2021-03-02 5:38 ` Dave Chinner
2021-03-02 5:50 ` Dan Williams
2021-03-02 3:28 ` Darrick J. Wong
2021-03-02 5:41 ` Dan Williams
2021-03-02 7:57 ` Dave Chinner
2021-03-02 17:49 ` Dan Williams
2021-03-04 23:40 ` Darrick J. Wong
2021-03-01 7:26 ` Yasunori Goto
2021-03-01 21:34 ` Dan Williams
[not found] ` <20210226002030.653855-5-ruansy.fnst@fujitsu.com>
2021-03-03 9:29 ` [Ocfs2-devel] [PATCH v2 04/10] fsdax: Introduce dax_iomap_cow_copy() Christoph Hellwig
[not found] ` <20210226002030.653855-7-ruansy.fnst@fujitsu.com>
2021-03-03 9:31 ` [Ocfs2-devel] [PATCH v2 06/10] fsdax: Add dax_iomap_cow_copy() for dax_iomap_zero Christoph Hellwig
[not found] ` <20210226002030.653855-8-ruansy.fnst@fujitsu.com>
2021-02-26 4:14 ` [Ocfs2-devel] [PATCH v2 07/10] iomap: Introduce iomap_apply2() for operations on two files Darrick J. Wong
2021-02-26 8:11 ` ruansy.fnst
2021-02-26 8:25 ` Shiyang Ruan
2021-03-04 5:41 ` [Ocfs2-devel] [RESEND PATCH v2.1 " Shiyang Ruan
2021-03-11 12:30 ` Christoph Hellwig
2021-03-09 6:36 ` [Ocfs2-devel] [PATCH v2 00/10] fsdax, xfs: Add reflink&dedupe support for fsdax Xiaoguang Wang
2021-03-10 1:32 ` ruansy.fnst
2021-03-09 16:19 ` Goldwyn Rodrigues
2021-03-10 1:26 ` ruansy.fnst
2021-03-10 12:30 ` Neal Gompa
2021-03-10 13:02 ` Matthew Wilcox
2021-03-10 13:36 ` Neal Gompa
2021-03-10 13:55 ` Matthew Wilcox
2021-03-10 14:21 ` Goldwyn Rodrigues
2021-03-10 14:26 ` Matthew Wilcox
2021-03-10 17:04 ` Goldwyn Rodrigues
2021-03-11 0:53 ` Dan Williams
2021-03-11 8:26 ` Neal Gompa
2021-03-13 13:07 ` Adam Borowski
2021-03-13 16:24 ` Neal Gompa
2021-03-13 22:00 ` Adam Borowski [this message]
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