ocfs2-devel.oss.oracle.com archive mirror
 help / color / mirror / Atom feed
From: "Darrick J. Wong" <djwong@kernel.org>
To: Ruan Shiyang <ruansy.fnst@cn.fujitsu.com>
Cc: jack@suse.cz, linux-nvdimm@lists.01.org, darrick.wong@oracle.com,
	david@fromorbit.com, linux-kernel@vger.kernel.org,
	linux-xfs@vger.kernel.org, ocfs2-devel@oss.oracle.com,
	viro@zeniv.linux.org.uk, Goldwyn Rodrigues <rgoldwyn@suse.com>,
	linux-fsdevel@vger.kernel.org, dan.j.williams@intel.com,
	linux-btrfs@vger.kernel.org
Subject: Re: [Ocfs2-devel] [PATCH 5/7] fsdax: Dedup file range to use a compare function
Date: Thu, 18 Feb 2021 08:20:18 -0800	[thread overview]
Message-ID: <20210218162018.GT7193@magnolia> (raw)
In-Reply-To: <b00cfda5-464c-6161-77c6-6a25b1cc7a77@cn.fujitsu.com>

On Wed, Feb 17, 2021 at 11:24:18AM +0800, Ruan Shiyang wrote:
> 
> 
> On 2021/2/10 下午9:19, Christoph Hellwig wrote:
> > On Tue, Feb 09, 2021 at 05:46:13PM +0800, Ruan Shiyang wrote:
> > > 
> > > 
> > > On 2021/2/9 下午5:34, Christoph Hellwig wrote:
> > > > On Tue, Feb 09, 2021 at 05:15:13PM +0800, Ruan Shiyang wrote:
> > > > > The dax dedupe comparison need the iomap_ops pointer as argument, so my
> > > > > understanding is that we don't modify the argument list of
> > > > > generic_remap_file_range_prep(), but move its code into
> > > > > __generic_remap_file_range_prep() whose argument list can be modified to
> > > > > accepts the iomap_ops pointer.  Then it looks like this:
> > > > 
> > > > I'd say just add the iomap_ops pointer to
> > > > generic_remap_file_range_prep and do away with the extra wrappers.  We
> > > > only have three callers anyway.
> > > 
> > > OK.
> > 
> > So looking at this again I think your proposal actaully is better,
> > given that the iomap variant is still DAX specific.  Sorry for
> > the noise.
> > 
> > Also I think dax_file_range_compare should use iomap_apply instead
> > of open coding it.
> > 
> 
> There are two files, which are not reflinked, need to be direct_access()
> here.  The iomap_apply() can handle one file each time.  So, it seems that
> iomap_apply() is not suitable for this case...
> 
> 
> The pseudo code of this process is as follows:
> 
>   srclen = ops->begin(&srcmap)
>   destlen = ops->begin(&destmap)
> 
>   direct_access(&srcmap, &saddr)
>   direct_access(&destmap, &daddr)
> 
>   same = memcpy(saddr, daddr, min(srclen,destlen))
> 
>   ops->end(&destmap)
>   ops->end(&srcmap)
> 
> I think a nested call like this is necessary.  That's why I use the open
> code way.

This might be a good place to implement an iomap_apply2() loop that
actually /does/ walk all the extents of file1 and file2.  There's now
two users of this idiom.

(Possibly structured as a "get next mappings from both" generator
function like Matthew Wilcox keeps asking for. :))

--D

> 
> --
> Thanks,
> Ruan Shiyang.
> > 
> 
> 

_______________________________________________
Ocfs2-devel mailing list
Ocfs2-devel@oss.oracle.com
https://oss.oracle.com/mailman/listinfo/ocfs2-devel

  reply	other threads:[~2021-02-26 16:55 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-07 17:09 [Ocfs2-devel] [PATCH 0/7] fsdax, xfs: Add reflink&dedupe support for fsdax Shiyang Ruan
2021-02-07 17:09 ` [Ocfs2-devel] [PATCH 1/7] fsdax: Output address in dax_iomap_pfn() and rename it Shiyang Ruan
2021-02-08 15:11   ` Christoph Hellwig
2021-02-22  7:44   ` Xiaoguang Wang
2021-02-23  1:32     ` [Ocfs2-devel] 回复: " ruansy.fnst
2021-02-07 17:09 ` [Ocfs2-devel] [PATCH 2/7] fsdax: Introduce dax_copy_edges() for CoW Shiyang Ruan
2021-02-08 15:11   ` Christoph Hellwig
2021-02-07 17:09 ` [Ocfs2-devel] [PATCH 3/7] fsdax: Copy data before write Shiyang Ruan
2021-02-08 15:14   ` Christoph Hellwig
2021-02-09  1:53     ` Ruan Shiyang
2021-02-07 17:09 ` [Ocfs2-devel] [PATCH 4/7] fsdax: Replace mmap entry in case of CoW Shiyang Ruan
2021-02-08 15:16   ` Christoph Hellwig
2021-02-16 13:11   ` David Sterba
2021-02-17  3:06     ` Ruan Shiyang
2021-02-07 17:09 ` [Ocfs2-devel] [PATCH 5/7] fsdax: Dedup file range to use a compare function Shiyang Ruan
2021-02-08 15:19   ` Christoph Hellwig
2021-02-09  9:15     ` Ruan Shiyang
2021-02-09  9:34       ` Christoph Hellwig
2021-02-09  9:46         ` Ruan Shiyang
2021-02-10 13:19           ` Christoph Hellwig
2021-02-17  3:24             ` Ruan Shiyang
2021-02-18 16:20               ` Darrick J. Wong [this message]
2021-02-25  7:35                 ` Christoph Hellwig
2021-02-07 17:09 ` [Ocfs2-devel] [PATCH 6/7] fs/xfs: Handle CoW for fsdax write() path Shiyang Ruan
2021-02-08 15:24   ` Christoph Hellwig
2021-02-07 17:09 ` [Ocfs2-devel] [PATCH 7/7] fs/xfs: Add dedupe support for fsdax Shiyang Ruan
2021-02-08 15:39 ` [Ocfs2-devel] [PATCH 0/7] fsdax, xfs: Add reflink&dedupe " Jan Kara
2021-02-09  1:50   ` Ruan Shiyang

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210218162018.GT7193@magnolia \
    --to=djwong@kernel.org \
    --cc=dan.j.williams@intel.com \
    --cc=darrick.wong@oracle.com \
    --cc=david@fromorbit.com \
    --cc=jack@suse.cz \
    --cc=linux-btrfs@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-nvdimm@lists.01.org \
    --cc=linux-xfs@vger.kernel.org \
    --cc=ocfs2-devel@oss.oracle.com \
    --cc=rgoldwyn@suse.com \
    --cc=ruansy.fnst@cn.fujitsu.com \
    --cc=viro@zeniv.linux.org.uk \
    --subject='Re: [Ocfs2-devel] [PATCH 5/7] fsdax: Dedup file range to use a compare function' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).